Merge branch 'master' into bbuf

BUILD

@@ -161,7 +161,6 @@ cc_library(
     "src/core/channel/context.h",
     "src/core/channel/http_client_filter.h",
     "src/core/channel/http_server_filter.h",
-    "src/core/channel/noop_filter.h",
     "src/core/channel/subchannel_call_holder.h",
     "src/core/client_config/client_config.h",
     "src/core/client_config/connector.h",
@@ -178,9 +177,8 @@ cc_library(
     "src/core/client_config/resolvers/sockaddr_resolver.h",
     "src/core/client_config/subchannel.h",
     "src/core/client_config/subchannel_factory.h",
-    "src/core/client_config/subchannel_factory_decorators/add_channel_arg.h",
-    "src/core/client_config/subchannel_factory_decorators/merge_channel_args.h",
     "src/core/client_config/uri_parser.h",
+    "src/core/compression/algorithm_metadata.h",
     "src/core/compression/message_compress.h",
     "src/core/debug/trace.h",
     "src/core/httpcli/format_request.h",
@@ -263,6 +261,7 @@ cc_library(
     "src/core/transport/connectivity_state.h",
     "src/core/transport/metadata.h",
     "src/core/transport/metadata_batch.h",
+    "src/core/transport/static_metadata.h",
     "src/core/transport/transport.h",
     "src/core/transport/transport_impl.h",
     "src/core/census/aggregation.h",
@@ -299,7 +298,6 @@ cc_library(
     "src/core/channel/connected_channel.c",
     "src/core/channel/http_client_filter.c",
     "src/core/channel/http_server_filter.c",
-    "src/core/channel/noop_filter.c",
     "src/core/channel/subchannel_call_holder.c",
     "src/core/client_config/client_config.c",
     "src/core/client_config/connector.c",
@@ -317,8 +315,6 @@ cc_library(
     "src/core/client_config/resolvers/sockaddr_resolver.c",
     "src/core/client_config/subchannel.c",
     "src/core/client_config/subchannel_factory.c",
-    "src/core/client_config/subchannel_factory_decorators/add_channel_arg.c",
-    "src/core/client_config/subchannel_factory_decorators/merge_channel_args.c",
     "src/core/client_config/uri_parser.c",
     "src/core/compression/algorithm.c",
     "src/core/compression/message_compress.c",
@@ -379,6 +375,7 @@ cc_library(
     "src/core/surface/channel.c",
     "src/core/surface/channel_connectivity.c",
     "src/core/surface/channel_create.c",
+    "src/core/surface/channel_ping.c",
     "src/core/surface/completion_queue.c",
     "src/core/surface/event_string.c",
     "src/core/surface/init.c",
@@ -413,6 +410,7 @@ cc_library(
     "src/core/transport/connectivity_state.c",
     "src/core/transport/metadata.c",
     "src/core/transport/metadata_batch.c",
+    "src/core/transport/static_metadata.c",
     "src/core/transport/transport.c",
     "src/core/transport/transport_op_string.c",
     "src/core/census/context.c",
@@ -454,7 +452,6 @@ cc_library(
     "src/core/channel/context.h",
     "src/core/channel/http_client_filter.h",
     "src/core/channel/http_server_filter.h",
-    "src/core/channel/noop_filter.h",
     "src/core/channel/subchannel_call_holder.h",
     "src/core/client_config/client_config.h",
     "src/core/client_config/connector.h",
@@ -471,9 +468,8 @@ cc_library(
     "src/core/client_config/resolvers/sockaddr_resolver.h",
     "src/core/client_config/subchannel.h",
     "src/core/client_config/subchannel_factory.h",
-    "src/core/client_config/subchannel_factory_decorators/add_channel_arg.h",
-    "src/core/client_config/subchannel_factory_decorators/merge_channel_args.h",
     "src/core/client_config/uri_parser.h",
+    "src/core/compression/algorithm_metadata.h",
     "src/core/compression/message_compress.h",
     "src/core/debug/trace.h",
     "src/core/httpcli/format_request.h",
@@ -556,6 +552,7 @@ cc_library(
     "src/core/transport/connectivity_state.h",
     "src/core/transport/metadata.h",
     "src/core/transport/metadata_batch.h",
+    "src/core/transport/static_metadata.h",
     "src/core/transport/transport.h",
     "src/core/transport/transport_impl.h",
     "src/core/census/aggregation.h",
@@ -572,7 +569,6 @@ cc_library(
     "src/core/channel/connected_channel.c",
     "src/core/channel/http_client_filter.c",
     "src/core/channel/http_server_filter.c",
-    "src/core/channel/noop_filter.c",
     "src/core/channel/subchannel_call_holder.c",
     "src/core/client_config/client_config.c",
     "src/core/client_config/connector.c",
@@ -590,8 +586,6 @@ cc_library(
     "src/core/client_config/resolvers/sockaddr_resolver.c",
     "src/core/client_config/subchannel.c",
     "src/core/client_config/subchannel_factory.c",
-    "src/core/client_config/subchannel_factory_decorators/add_channel_arg.c",
-    "src/core/client_config/subchannel_factory_decorators/merge_channel_args.c",
     "src/core/client_config/uri_parser.c",
     "src/core/compression/algorithm.c",
     "src/core/compression/message_compress.c",
@@ -652,6 +646,7 @@ cc_library(
     "src/core/surface/channel.c",
     "src/core/surface/channel_connectivity.c",
     "src/core/surface/channel_create.c",
+    "src/core/surface/channel_ping.c",
     "src/core/surface/completion_queue.c",
     "src/core/surface/event_string.c",
     "src/core/surface/init.c",
@@ -686,6 +681,7 @@ cc_library(
     "src/core/transport/connectivity_state.c",
     "src/core/transport/metadata.c",
     "src/core/transport/metadata_batch.c",
+    "src/core/transport/static_metadata.c",
     "src/core/transport/transport.c",
     "src/core/transport/transport_op_string.c",
     "src/core/census/context.c",
@@ -742,14 +738,13 @@ cc_library(
     "src/cpp/server/dynamic_thread_pool.h",
     "src/cpp/server/fixed_size_thread_pool.h",
     "src/cpp/server/thread_pool_interface.h",
-    "src/cpp/client/secure_channel_arguments.cc",
     "src/cpp/client/secure_credentials.cc",
     "src/cpp/common/auth_property_iterator.cc",
     "src/cpp/common/secure_auth_context.cc",
+    "src/cpp/common/secure_channel_arguments.cc",
     "src/cpp/common/secure_create_auth_context.cc",
     "src/cpp/server/secure_server_credentials.cc",
     "src/cpp/client/channel.cc",
-    "src/cpp/client/channel_arguments.cc",
     "src/cpp/client/client_context.cc",
     "src/cpp/client/create_channel.cc",
     "src/cpp/client/create_channel_internal.cc",
@@ -757,6 +752,7 @@ cc_library(
     "src/cpp/client/generic_stub.cc",
     "src/cpp/client/insecure_credentials.cc",
     "src/cpp/common/call.cc",
+    "src/cpp/common/channel_arguments.cc",
     "src/cpp/common/completion_queue.cc",
     "src/cpp/common/rpc_method.cc",
     "src/cpp/proto/proto_utils.cc",
@@ -790,6 +786,7 @@ cc_library(
     "include/grpc++/impl/rpc_method.h",
     "include/grpc++/impl/rpc_service_method.h",
     "include/grpc++/impl/serialization_traits.h",
+    "include/grpc++/impl/server_builder_option.h",
     "include/grpc++/impl/service_type.h",
     "include/grpc++/impl/sync.h",
     "include/grpc++/impl/sync_cxx11.h",
@@ -841,7 +838,6 @@ cc_library(
     "src/cpp/server/thread_pool_interface.h",
     "src/cpp/common/insecure_create_auth_context.cc",
     "src/cpp/client/channel.cc",
-    "src/cpp/client/channel_arguments.cc",
     "src/cpp/client/client_context.cc",
     "src/cpp/client/create_channel.cc",
     "src/cpp/client/create_channel_internal.cc",
@@ -849,6 +845,7 @@ cc_library(
     "src/cpp/client/generic_stub.cc",
     "src/cpp/client/insecure_credentials.cc",
     "src/cpp/common/call.cc",
+    "src/cpp/common/channel_arguments.cc",
     "src/cpp/common/completion_queue.cc",
     "src/cpp/common/rpc_method.cc",
     "src/cpp/proto/proto_utils.cc",
@@ -882,6 +879,7 @@ cc_library(
     "include/grpc++/impl/rpc_method.h",
     "include/grpc++/impl/rpc_service_method.h",
     "include/grpc++/impl/serialization_traits.h",
+    "include/grpc++/impl/server_builder_option.h",
     "include/grpc++/impl/service_type.h",
     "include/grpc++/impl/sync.h",
     "include/grpc++/impl/sync_cxx11.h",
@@ -1105,7 +1103,6 @@ objc_library(
     "src/core/channel/connected_channel.c",
     "src/core/channel/http_client_filter.c",
     "src/core/channel/http_server_filter.c",
-    "src/core/channel/noop_filter.c",
     "src/core/channel/subchannel_call_holder.c",
     "src/core/client_config/client_config.c",
     "src/core/client_config/connector.c",
@@ -1123,8 +1120,6 @@ objc_library(
     "src/core/client_config/resolvers/sockaddr_resolver.c",
     "src/core/client_config/subchannel.c",
     "src/core/client_config/subchannel_factory.c",
-    "src/core/client_config/subchannel_factory_decorators/add_channel_arg.c",
-    "src/core/client_config/subchannel_factory_decorators/merge_channel_args.c",
     "src/core/client_config/uri_parser.c",
     "src/core/compression/algorithm.c",
     "src/core/compression/message_compress.c",
@@ -1185,6 +1180,7 @@ objc_library(
     "src/core/surface/channel.c",
     "src/core/surface/channel_connectivity.c",
     "src/core/surface/channel_create.c",
+    "src/core/surface/channel_ping.c",
     "src/core/surface/completion_queue.c",
     "src/core/surface/event_string.c",
     "src/core/surface/init.c",
@@ -1219,6 +1215,7 @@ objc_library(
     "src/core/transport/connectivity_state.c",
     "src/core/transport/metadata.c",
     "src/core/transport/metadata_batch.c",
+    "src/core/transport/static_metadata.c",
     "src/core/transport/transport.c",
     "src/core/transport/transport_op_string.c",
     "src/core/census/context.c",
@@ -1257,7 +1254,6 @@ objc_library(
     "src/core/channel/context.h",
     "src/core/channel/http_client_filter.h",
     "src/core/channel/http_server_filter.h",
-    "src/core/channel/noop_filter.h",
     "src/core/channel/subchannel_call_holder.h",
     "src/core/client_config/client_config.h",
     "src/core/client_config/connector.h",
@@ -1274,9 +1270,8 @@ objc_library(
     "src/core/client_config/resolvers/sockaddr_resolver.h",
     "src/core/client_config/subchannel.h",
     "src/core/client_config/subchannel_factory.h",
-    "src/core/client_config/subchannel_factory_decorators/add_channel_arg.h",
-    "src/core/client_config/subchannel_factory_decorators/merge_channel_args.h",
     "src/core/client_config/uri_parser.h",
+    "src/core/compression/algorithm_metadata.h",
     "src/core/compression/message_compress.h",
     "src/core/debug/trace.h",
     "src/core/httpcli/format_request.h",
@@ -1359,6 +1354,7 @@ objc_library(
     "src/core/transport/connectivity_state.h",
     "src/core/transport/metadata.h",
     "src/core/transport/metadata_batch.h",
+    "src/core/transport/static_metadata.h",
     "src/core/transport/transport.h",
     "src/core/transport/transport_impl.h",
     "src/core/census/aggregation.h",

README.md

@@ -13,34 +13,28 @@ You can find more detailed documentation and examples in the [doc](doc) and [exa
 
 See grpc/INSTALL for installation instructions for various platforms.
 
-#Repository Structure
+#Repository Structure & Status
 
-This repository contains source code for gRPC libraries for multiple languages written on top
-of shared C core library [src/core] (src/core).
+This repository contains source code for gRPC libraries for multiple languages written on top of shared C core library [src/core] (src/core).
 
-   * C++ source code: [src/cpp] (src/cpp)
-   * Ruby source code: [src/ruby] (src/ruby)
-   * NodeJS source code: [src/node] (src/node)
-   * Python source code: [src/python] (src/python)
-   * PHP source code: [src/php] (src/php)
-   * C# source code: [src/csharp] (src/csharp)
-   * Objective-C source code: [src/objective-c] (src/objective-c)
+Libraries in different languages are in different state of development. We are seeking contributions for all of these libraries.
 
+| Language                | Source                              | Status                          |
+|-------------------------|-------------------------------------|---------------------------------|
+| Shared C [core library] | [src/core] (src/core)               | Beta - the surface API is stable |
+| C++                     | [src/cpp] (src/cpp)                 | Beta - the surface API is stable |
+| Ruby                    | [src/ruby] (src/ruby)               | Beta - the surface API is stable |
+| NodeJS                  | [src/node] (src/node)               | Beta - the surface API is stable |
+| Python                  | [src/python] (src/python)           | Beta - the surface API is stable |
+| PHP                     | [src/php] (src/php)                 | Beta - the surface API is stable |
+| C#                      | [src/csharp] (src/csharp)           | Beta - the surface API is stable |
+| Objective-C             | [src/objective-c] (src/objective-c) | Beta - the surface API is stable |
+
+<small>
 Java source code is in [grpc-java] (http://github.com/grpc/grpc-java) repository.
 Go source code is in [grpc-go] (http://github.com/grpc/grpc-go) repository.
+</small>
 
-#Current Status of libraries
-
-Libraries in different languages are in different state of development. We are seeking contributions for all of these libraries.
-
-   * shared C core library [src/core] (src/core) : Beta - the surface API is stable
-   * C++ Library: [src/cpp] (src/cpp) : Beta - the surface API is stable
-   * Ruby Library: [src/ruby] (src/ruby) : Beta - the surface API is stable
-   * NodeJS Library: [src/node] (src/node) : Beta - the surface API is stable
-   * Python Library: [src/python] (src/python) : Beta - the surface API is stable
-   * C# Library: [src/csharp] (src/csharp) : Beta - the surface API is stable
-   * Objective-C Library: [src/objective-c] (src/objective-c): Beta - the surface API is stable
-   * PHP Library: [src/php] (src/php) : Beta - the surface API is stable
 
 #Overview
 

binding.gyp

@@ -183,7 +183,6 @@
         'src/core/channel/connected_channel.c',
         'src/core/channel/http_client_filter.c',
         'src/core/channel/http_server_filter.c',
-        'src/core/channel/noop_filter.c',
         'src/core/channel/subchannel_call_holder.c',
         'src/core/client_config/client_config.c',
         'src/core/client_config/connector.c',
@@ -201,8 +200,6 @@
         'src/core/client_config/resolvers/sockaddr_resolver.c',
         'src/core/client_config/subchannel.c',
         'src/core/client_config/subchannel_factory.c',
-        'src/core/client_config/subchannel_factory_decorators/add_channel_arg.c',
-        'src/core/client_config/subchannel_factory_decorators/merge_channel_args.c',
         'src/core/client_config/uri_parser.c',
         'src/core/compression/algorithm.c',
         'src/core/compression/message_compress.c',
@@ -263,6 +260,7 @@
         'src/core/surface/channel.c',
         'src/core/surface/channel_connectivity.c',
         'src/core/surface/channel_create.c',
+        'src/core/surface/channel_ping.c',
         'src/core/surface/completion_queue.c',
         'src/core/surface/event_string.c',
         'src/core/surface/init.c',
@@ -297,6 +295,7 @@
         'src/core/transport/connectivity_state.c',
         'src/core/transport/metadata.c',
         'src/core/transport/metadata_batch.c',
+        'src/core/transport/static_metadata.c',
         'src/core/transport/transport.c',
         'src/core/transport/transport_op_string.c',
         'src/core/census/context.c',

build.yaml

@@ -37,6 +37,7 @@ filegroups:
   - include/grpc++/impl/rpc_method.h
   - include/grpc++/impl/rpc_service_method.h
   - include/grpc++/impl/serialization_traits.h
+  - include/grpc++/impl/server_builder_option.h
   - include/grpc++/impl/service_type.h
   - include/grpc++/impl/sync.h
   - include/grpc++/impl/sync_cxx11.h
@@ -72,7 +73,6 @@ filegroups:
   - src/cpp/server/thread_pool_interface.h
   src:
   - src/cpp/client/channel.cc
-  - src/cpp/client/channel_arguments.cc
   - src/cpp/client/client_context.cc
   - src/cpp/client/create_channel.cc
   - src/cpp/client/create_channel_internal.cc
@@ -80,6 +80,7 @@ filegroups:
   - src/cpp/client/generic_stub.cc
   - src/cpp/client/insecure_credentials.cc
   - src/cpp/common/call.cc
+  - src/cpp/common/channel_arguments.cc
   - src/cpp/common/completion_queue.cc
   - src/cpp/common/rpc_method.cc
   - src/cpp/proto/proto_utils.cc
@@ -115,7 +116,6 @@ filegroups:
   - src/core/channel/context.h
   - src/core/channel/http_client_filter.h
   - src/core/channel/http_server_filter.h
-  - src/core/channel/noop_filter.h
   - src/core/channel/subchannel_call_holder.h
   - src/core/client_config/client_config.h
   - src/core/client_config/connector.h
@@ -132,9 +132,8 @@ filegroups:
   - src/core/client_config/resolvers/sockaddr_resolver.h
   - src/core/client_config/subchannel.h
   - src/core/client_config/subchannel_factory.h
-  - src/core/client_config/subchannel_factory_decorators/add_channel_arg.h
-  - src/core/client_config/subchannel_factory_decorators/merge_channel_args.h
   - src/core/client_config/uri_parser.h
+  - src/core/compression/algorithm_metadata.h
   - src/core/compression/message_compress.h
   - src/core/debug/trace.h
   - src/core/httpcli/format_request.h
@@ -217,6 +216,7 @@ filegroups:
   - src/core/transport/connectivity_state.h
   - src/core/transport/metadata.h
   - src/core/transport/metadata_batch.h
+  - src/core/transport/static_metadata.h
   - src/core/transport/transport.h
   - src/core/transport/transport_impl.h
   src:
@@ -230,7 +230,6 @@ filegroups:
   - src/core/channel/connected_channel.c
   - src/core/channel/http_client_filter.c
   - src/core/channel/http_server_filter.c
-  - src/core/channel/noop_filter.c
   - src/core/channel/subchannel_call_holder.c
   - src/core/client_config/client_config.c
   - src/core/client_config/connector.c
@@ -248,8 +247,6 @@ filegroups:
   - src/core/client_config/resolvers/sockaddr_resolver.c
   - src/core/client_config/subchannel.c
   - src/core/client_config/subchannel_factory.c
-  - src/core/client_config/subchannel_factory_decorators/add_channel_arg.c
-  - src/core/client_config/subchannel_factory_decorators/merge_channel_args.c
   - src/core/client_config/uri_parser.c
   - src/core/compression/algorithm.c
   - src/core/compression/message_compress.c
@@ -310,6 +307,7 @@ filegroups:
   - src/core/surface/channel.c
   - src/core/surface/channel_connectivity.c
   - src/core/surface/channel_create.c
+  - src/core/surface/channel_ping.c
   - src/core/surface/completion_queue.c
   - src/core/surface/event_string.c
   - src/core/surface/init.c
@@ -344,6 +342,7 @@ filegroups:
   - src/core/transport/connectivity_state.c
   - src/core/transport/metadata.c
   - src/core/transport/metadata_batch.c
+  - src/core/transport/static_metadata.c
   - src/core/transport/transport.c
   - src/core/transport/transport_op_string.c
 - name: grpc_test_util_base
@@ -351,7 +350,6 @@ filegroups:
   - test/core/end2end/cq_verifier.h
   - test/core/end2end/fixtures/proxy.h
   - test/core/iomgr/endpoint_tests.h
-  - test/core/security/oauth2_utils.h
   - test/core/util/grpc_profiler.h
   - test/core/util/parse_hexstring.h
   - test/core/util/port.h
@@ -360,7 +358,6 @@ filegroups:
   - test/core/end2end/cq_verifier.c
   - test/core/end2end/fixtures/proxy.c
   - test/core/iomgr/endpoint_tests.c
-  - test/core/security/oauth2_utils.c
   - test/core/util/grpc_profiler.c
   - test/core/util/parse_hexstring.c
   - test/core/util/port_posix.c
@@ -523,10 +520,12 @@ libs:
   language: c
   headers:
   - test/core/end2end/data/ssl_test_data.h
+  - test/core/security/oauth2_utils.h
   src:
   - test/core/end2end/data/server1_cert.c
   - test/core/end2end/data/server1_key.c
   - test/core/end2end/data/test_root_cert.c
+  - test/core/security/oauth2_utils.c
   deps:
   - gpr
   - gpr_test_util
@@ -540,7 +539,7 @@ libs:
   deps:
   - gpr
   - gpr_test_util
-  - grpc
+  - grpc_unsecure
   filegroups:
   - grpc_test_util_base
   secure: false
@@ -609,10 +608,10 @@ libs:
   - src/cpp/common/secure_auth_context.h
   - src/cpp/server/secure_server_credentials.h
   src:
-  - src/cpp/client/secure_channel_arguments.cc
   - src/cpp/client/secure_credentials.cc
   - src/cpp/common/auth_property_iterator.cc
   - src/cpp/common/secure_auth_context.cc
+  - src/cpp/common/secure_channel_arguments.cc
   - src/cpp/common/secure_create_auth_context.cc
   - src/cpp/server/secure_server_credentials.cc
   deps:
@@ -811,6 +810,24 @@ libs:
   - winsock
   - global
 targets:
+- name: algorithm_test
+  build: test
+  language: c
+  src:
+  - test/core/compression/algorithm_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+- name: alloc_test
+  build: test
+  language: c
+  src:
+  - test/core/support/alloc_test.c
+  deps:
+  - gpr_test_util
+  - gpr
 - name: alpn_test
   build: test
   language: c
@@ -831,6 +848,16 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: channel_create_test
+  build: test
+  language: c
+  src:
+  - test/core/surface/channel_create_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: chttp2_hpack_encoder_test
   build: test
   language: c
@@ -861,6 +888,16 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: chttp2_varint_test
+  build: test
+  language: c
+  src:
+  - test/core/transport/chttp2/varint_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: compression_test
   build: test
   language: c
@@ -871,6 +908,16 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: dns_resolver_test
+  build: test
+  language: c
+  src:
+  - test/core/client_config/resolvers/dns_resolver_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: dualstack_socket_test
   build: test
   language: c
@@ -1213,6 +1260,16 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: grpc_invalid_channel_args_test
+  build: test
+  language: c
+  src:
+  - test/core/surface/invalid_channel_args_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: grpc_json_token_test
   build: test
   language: c
@@ -1321,6 +1378,38 @@ targets:
   - mac
   - linux
   - posix
+- name: httpscli_test
+  build: test
+  language: c
+  src:
+  - test/core/httpcli/httpscli_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+  platforms:
+  - linux
+- name: init_test
+  build: test
+  language: c
+  src:
+  - test/core/surface/init_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+- name: invalid_call_argument_test
+  build: test
+  language: c
+  src:
+  - test/core/end2end/invalid_call_argument_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: json_rewrite
   build: test
   run: false
@@ -1340,6 +1429,16 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: json_stream_error_test
+  build: test
+  language: c
+  src:
+  - test/core/json/json_stream_error_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: json_test
   build: test
   language: c
@@ -1394,16 +1493,6 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
-- name: multi_init_test
-  build: test
-  language: c
-  src:
-  - test/core/surface/multi_init_test.c
-  deps:
-  - grpc_test_util
-  - grpc
-  - gpr_test_util
-  - gpr
 - name: multiple_server_queues_test
   build: test
   language: c
@@ -1442,6 +1531,16 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: secure_channel_create_test
+  build: test
+  language: c
+  src:
+  - test/core/surface/secure_channel_create_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: secure_endpoint_test
   build: test
   language: c
@@ -1452,6 +1551,26 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: server_chttp2_test
+  build: test
+  language: c
+  src:
+  - test/core/surface/server_chttp2_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+- name: server_test
+  build: test
+  language: c
+  src:
+  - test/core/surface/server_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: set_initial_connect_string_test
   build: test
   language: c
@@ -1463,6 +1582,16 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: sockaddr_resolver_test
+  build: test
+  language: c
+  src:
+  - test/core/client_config/resolvers/sockaddr_resolver_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: sockaddr_utils_test
   build: test
   language: c
@@ -1473,6 +1602,20 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: socket_utils_test
+  build: test
+  language: c
+  src:
+  - test/core/iomgr/socket_utils_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+  platforms:
+  - mac
+  - linux
+  - posix
 - name: tcp_client_posix_test
   build: test
   language: c
@@ -1565,6 +1708,16 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: transport_connectivity_state_test
+  build: test
+  language: c
+  src:
+  - test/core/transport/connectivity_state_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: transport_metadata_test
   build: test
   language: c
@@ -1689,7 +1842,7 @@ targets:
   build: test
   language: c++
   src:
-  - test/cpp/client/channel_arguments_test.cc
+  - test/cpp/common/channel_arguments_test.cc
   deps:
   - grpc++
   - grpc
@@ -2266,11 +2419,11 @@ vspackages:
   name: grpc.dependencies.zlib
   props: false
   redist: true
-  version: 1.2.8.9
+  version: 1.2.8.10
 - name: grpc.dependencies.openssl
   props: true
   redist: true
-  version: 1.0.2.3
+  version: 1.0.204.1
 - name: gflags
   props: false
   redist: false

doc/PROTOCOL-HTTP2.md

@@ -45,7 +45,7 @@ Request-Headers are delivered as HTTP2 headers in HEADERS + CONTINUATION frames.
 * **Custom-Metadata** → Binary-Header / ASCII-Header
 * **Binary-Header** → {Header-Name "-bin" } {_base64 encoded value_}
 * **ASCII-Header** → Header-Name ASCII-Value
-* **Header-Name** → 1\*( %x30-39 / %x61-7A / "\_" / "-") ; 0-9 a-z \_ -
+* **Header-Name** → 1\*( %x30-39 / %x61-7A / "\_" / "-" / ".") ; 0-9 a-z \_ - .
 * **ASCII-Value** → 1\*( %x20-%x7E ) ; space and printable ASCII
 
 

doc/grpc-auth-support.md

@@ -1,289 +0,0 @@
-#gRPC Authentication support
-
-gRPC is designed to plug-in a number of authentication mechanisms. This document
-provides a quick overview of the various auth mechanisms supported, discusses
-the API with some examples, and concludes with a discussion of extensibility.
-More documentation and examples are coming soon!
-
-## Supported auth mechanisms
-
-###SSL/TLS
-gRPC has SSL/TLS integration and promotes the use of SSL/TLS to authenticate the
-server, and encrypt all the data exchanged between the client and the server.
-Optional mechanisms are available for clients to provide certificates to
-accomplish mutual authentication.
-
-###OAuth 2.0
-gRPC provides a generic mechanism (described below) to attach metadata to
-requests and responses. This mechanism can be used to attach OAuth 2.0 Access
-Tokens to RPCs being made at a client. Additional support for acquiring Access
-Tokens while accessing Google APIs through gRPC is provided for certain auth
-flows, demonstrated through code examples below.
-
-## API
-To reduce complexity and minimize API clutter, gRPC works with a unified concept
-of a Credentials object. Users construct gRPC credentials using corresponding
-bootstrap credentials (e.g., SSL client certs or Service Account Keys), and use
-the credentials while creating a gRPC channel to any server. Depending on the
-type of credential supplied, the channel uses the credentials during the initial
-SSL/TLS handshake with the server, or uses  the credential to generate and
-attach Access Tokens to each request being made on the channel.
-
-###SSL/TLS for server authentication and encryption
-This is the simplest authentication scenario, where a client just wants to
-authenticate the server and encrypt all data.
-
-```cpp
-SslCredentialsOptions ssl_opts;  // Options to override SSL params, empty by default
-// Create the credentials object by providing service account key in constructor
-std::shared_ptr<ChannelCredentials> creds = SslCredentials(ssl_opts);
-// Create a channel using the credentials created in the previous step
-std::shared_ptr<Channel> channel = CreateChannel(server_name, creds);
-// Create a stub on the channel
-std::unique_ptr<Greeter::Stub> stub(Greeter::NewStub(channel));
-// Make actual RPC calls on the stub.
-grpc::Status s = stub->sayHello(&context, *request, response);
-```
-
-For advanced use cases such as modifying the root CA or using client certs,
-the corresponding options can be set in the SslCredentialsOptions parameter
-passed to the factory method.
-
-
-###Authenticating with Google
-
-gRPC applications can use a simple API to create a credential that works in various deployment scenarios.
-
-```cpp
-std::shared_ptr<ChannelCredentials> creds = GoogleDefaultCredentials();
-// Create a channel, stub and make RPC calls (same as in the previous example)
-std::shared_ptr<Channel> channel = CreateChannel(server_name, creds);
-std::unique_ptr<Greeter::Stub> stub(Greeter::NewStub(channel));
-grpc::Status s = stub->sayHello(&context, *request, response);
-```
-
-This credential works for applications using Service Accounts as well as for
-applications running in [Google Compute Engine (GCE)](https://cloud.google.com/compute/). In the former case, the
-service account’s private keys are loaded from the file named in the environment
-variable `GOOGLE_APPLICATION_CREDENTIALS`. The
-keys are used to generate bearer tokens that are attached to each outgoing RPC
-on the corresponding channel.
-
-For applications running in GCE, a default service account and corresponding
-OAuth scopes can be configured during VM setup. At run-time, this credential
-handles communication with the authentication systems to obtain OAuth2 access
-tokens and attaches them to each outgoing RPC on the corresponding channel.
-Extending gRPC to support other authentication mechanisms
-The gRPC protocol is designed with a general mechanism for sending metadata
-associated with RPC. Clients can send metadata at the beginning of an RPC and
-servers can send back metadata at the beginning and end of the RPC. This
-provides a natural mechanism to support OAuth2 and other authentication
-mechanisms that need attach bearer tokens to individual request.
-
-In the simplest case, there is a single line of code required on the client
-to add a specific token as metadata to an RPC and a corresponding access on
-the server to retrieve this piece of metadata. The generation of the token
-on the client side and its verification at the server can be done separately.
-
-A deeper integration can be achieved by plugging in a gRPC credentials implementation for any custom authentication mechanism that needs to attach per-request tokens. gRPC internals also allow switching out SSL/TLS with other encryption mechanisms.
-
-## Examples
-
-These authentication mechanisms will be available in all gRPC's supported languages.
-The following sections demonstrate how authentication and authorization features described above appear in each language: more languages are coming soon.
-
-###SSL/TLS for server authentication and encryption (Ruby)
-```ruby
-# Base case - No encryption
-stub = Helloworld::Greeter::Stub.new('localhost:50051')
-...
-
-# With server authentication SSL/TLS
-creds = GRPC::Core::Credentials.new(load_certs)  # load_certs typically loads a CA roots file
-stub = Helloworld::Greeter::Stub.new('localhost:50051', creds: creds)
-```
-
-###SSL/TLS for server authentication and encryption (C#)
-```csharp
-// Base case - No encryption
-var channel = new Channel("localhost:50051");
-var client = new Greeter.GreeterClient(channel);
-...
-
-// With server authentication SSL/TLS
-var credentials = new SslCredentials(File.ReadAllText("ca.pem"));  // Load a CA file
-var channel = new Channel("localhost:50051", credentials);
-var client = new Greeter.GreeterClient(channel);
-```
-
-###SSL/TLS for server authentication and encryption (Objective-C)
-
-The default for Objective-C is to use SSL/TLS, as that's the most common use case when accessing
-remote APIs.
-
-```objective-c
-// Base case - With server authentication SSL/TLS
-HLWGreeter *client = [[HLWGreeter alloc] initWithHost:@"localhost:50051"];
-// Same as using @"https://localhost:50051".
-...
-
-// No encryption
-HLWGreeter *client = [[HLWGreeter alloc] initWithHost:@"http://localhost:50051"];
-// Specifying the HTTP scheme explicitly forces no encryption.
-```
-
-###SSL/TLS for server authentication and encryption (Python)
-```python
-# Base case - No encryption
-stub = early_adopter_create_GreeterService_stub('localhost', 50051)
-...
-
-# With server authentication SSL/TLS
-stub = early_adopter_create_GreeterService_stub(
-  'localhost', 50051, secure=True, root_certificates=open('ca.pem').read())
-...
-```
-n.b.: the beta API will look different
-
-###Authenticating with Google (Ruby)
-```ruby
-# Base case - No encryption/authorization
-stub = Helloworld::Greeter::Stub.new('localhost:50051')
-...
-
-# Authenticating with Google
-require 'googleauth'  # from http://www.rubydoc.info/gems/googleauth/0.1.0
-...
-creds = GRPC::Core::Credentials.new(load_certs)  # load_certs typically loads a CA roots file
-scope = 'https://www.googleapis.com/auth/grpc-testing'
-authorization = Google::Auth.get_application_default(scope)
-stub = Helloworld::Greeter::Stub.new('localhost:50051',
-                                     creds: creds,
-                                     update_metadata: authorization.updater_proc)
-```
-
-###Authenticating with Google (Node.js)
-
-```node
-// Base case - No encryption/authorization
-var stub = new helloworld.Greeter('localhost:50051');
-...
-// Authenticating with Google
-var GoogleAuth = require('google-auth-library'); // from https://www.npmjs.com/package/google-auth-library
-...
-var creds = grpc.Credentials.createSsl(load_certs); // load_certs typically loads a CA roots file
-var scope = 'https://www.googleapis.com/auth/grpc-testing';
-(new GoogleAuth()).getApplicationDefault(function(err, auth) {
-  if (auth.createScopeRequired()) {
-    auth = auth.createScoped(scope);
-  }
-  var stub = new helloworld.Greeter('localhost:50051',
-                                    {credentials: creds},
-                                    grpc.getGoogleAuthDelegate(auth));
-});
-```
-
-###Authenticating with Google (C#)
-```csharp
-// Base case - No encryption/authorization
-var channel = new Channel("localhost:50051");
-var client = new Greeter.GreeterClient(channel);
-...
-
-// Authenticating with Google
-using Grpc.Auth;  // from Grpc.Auth NuGet package
-...
-var credentials = new SslCredentials(File.ReadAllText("ca.pem"));  // Load a CA file
-var channel = new Channel("localhost:50051", credentials);
-
-string scope = "https://www.googleapis.com/auth/grpc-testing";
-var authorization = GoogleCredential.GetApplicationDefault();
-if (authorization.IsCreateScopedRequired)
-{
-    authorization = credential.CreateScoped(new[] { scope });
-}
-var client = new Greeter.GreeterClient(channel,
-        new StubConfiguration(OAuth2InterceptorFactory.Create(credential)));
-```
-
-###Authenticating with Google (PHP)
-```php
-// Base case - No encryption/authorization
-$client = new helloworld\GreeterClient(
-  new Grpc\BaseStub('localhost:50051', []));
-...
-
-// Authenticating with Google
-// the environment variable "GOOGLE_APPLICATION_CREDENTIALS" needs to be set
-$scope = "https://www.googleapis.com/auth/grpc-testing";
-$auth = Google\Auth\ApplicationDefaultCredentials::getCredentials($scope);
-$opts = [
-  'credentials' => Grpc\Credentials::createSsl(file_get_contents('ca.pem'));
-  'update_metadata' => $auth->getUpdateMetadataFunc(),
-];
-
-$client = new helloworld\GreeterClient(
-  new Grpc\BaseStub('localhost:50051', $opts));
-
-```
-
-###Authenticating with Google (Objective-C)
-
-This example uses the [Google iOS Sign-In library](https://developers.google.com/identity/sign-in/ios/),
-but it's easily extrapolated to any other OAuth2 library.
-
-```objective-c
-// Base case - No authentication
-[client sayHelloWithRequest:request handler:^(HLWHelloReply *response, NSError *error) {
-  ...
-}];
-
-...
-
-// Authenticating with Google
-
-// When signing the user in, ask her for the relevant scopes.
-GIDSignIn.sharedInstance.scopes = @[@"https://www.googleapis.com/auth/grpc-testing"];
-
-...
-
-#import <ProtoRPC/ProtoRPC.h>
-
-// Create a not-yet-started RPC. We want to set the request headers on this object before starting
-// it.
-ProtoRPC *call =
-    [client RPCToSayHelloWithRequest:request handler:^(HLWHelloReply *response, NSError *error) {
-      ...
-    }];
-
-// Set the access token to be used.
-NSString *accessToken = GIDSignIn.sharedInstance.currentUser.authentication.accessToken;
-call.requestMetadata[@"Authorization"] = [@"Bearer " stringByAppendingString:accessToken]}];
-
-// Start the RPC.
-[call start];
-```
-
-You can see a working example app, with a more detailed explanation, [here](examples/objective-c/auth_sample).
-
-### Authenticating with Google (Python)
-```python
-# Base case - No encryption
-stub = early_adopter_create_GreeterService_stub('localhost', 50051)
-...
-
-# With server authentication SSL/TLS
-import oauth2client.client
-credentials = oauth2client.GoogleCredentials.get_application_default()
-scope = 'https://www.googleapis.com/auth/grpc-testing'
-scoped_credentials = credentials.create_scoped([scope])
-access_token = scoped_credentials.get_access_token().access_token
-metadata_transformer = (
-    lambda x: [('Authorization', 'Bearer {}'.format(access_token))])
-
-stub = early_adopter_create_GreeterService_stub(
-  'localhost', 50051, secure=True, root_certificates=open('ca.pem').read(),
-  metadata_transformer=metadata_transformer)
-...
-```
-n.b.: the beta API will look different

examples/cpp/helloworld/README.md

@@ -41,7 +41,7 @@ message from the remote client containing the user's name, then send back
 a greeting in a single `HelloReply`. This is the simplest type of RPC you
 can specify in gRPC - we'll look at some other types later in this document.
 
-```
+```protobuf
 syntax = "proto3";
 
 option java_package = "ex.grpc";
@@ -93,20 +93,20 @@ $ protoc -I ../../protos/ --cpp_out=. ../../protos/helloworld.proto
   channel can be created with the target address, credentials to use and
   arguments as follows
 
-    ```
+    ```cpp
     auto channel = CreateChannel("localhost:50051", InsecureChannelCredentials());
     ```
 
 - Create a stub. A stub implements the rpc methods of a service and in the
   generated code, a method is provided to created a stub with a channel:
 
-    ```
+    ```cpp
     auto stub = helloworld::Greeter::NewStub(channel);
     ```
 
 - Make a unary rpc, with `ClientContext` and request/response proto messages.
 
-    ```
+    ```cpp
     ClientContext context;
     HelloRequest request;
     request.set_name("hello");
@@ -116,7 +116,7 @@ $ protoc -I ../../protos/ --cpp_out=. ../../protos/helloworld.proto
 
 - Check returned status and response.
 
-    ```
+    ```cpp
     if (status.ok()) {
       // check reply.message()
     } else {
@@ -130,7 +130,7 @@ For a working example, refer to [greeter_client.cc](greeter_client.cc).
 
 - Implement the service interface
 
-    ```
+    ```cpp
     class GreeterServiceImpl final : public Greeter::Service {
       Status SayHello(ServerContext* context, const HelloRequest* request,
           HelloReply* reply) override {
@@ -144,7 +144,7 @@ For a working example, refer to [greeter_client.cc](greeter_client.cc).
 
 - Build a server exporting the service
 
-    ```
+    ```cpp
     GreeterServiceImpl service;
     ServerBuilder builder;
     builder.AddListeningPort("0.0.0.0:50051", grpc::InsecureServerCredentials());
@@ -170,14 +170,14 @@ The channel and stub creation code is the same as the sync client.
 - Initiate the rpc and create a handle for the rpc. Bind the rpc to a
   `CompletionQueue`.
 
-    ```
+    ```cpp
     CompletionQueue cq;
     auto rpc = stub->AsyncSayHello(&context, request, &cq);
     ```
 
 - Ask for reply and final status, with a unique tag
 
-    ```
+    ```cpp
     Status status;
     rpc->Finish(&reply, &status, (void*)1);
     ```
@@ -185,7 +185,7 @@ The channel and stub creation code is the same as the sync client.
 - Wait for the completion queue to return the next tag. The reply and status are
   ready once the tag passed into the corresponding `Finish()` call is returned.
 
-    ```
+    ```cpp
     void* got_tag;
     bool ok = false;
     cq.Next(&got_tag, &ok);
@@ -203,7 +203,7 @@ completion queue to return the tag. The basic flow is
 
 - Build a server exporting the async service
 
-    ```
+    ```cpp
     helloworld::Greeter::AsyncService service;
     ServerBuilder builder;
     builder.AddListeningPort("0.0.0.0:50051", InsecureServerCredentials());
@@ -214,7 +214,7 @@ completion queue to return the tag. The basic flow is
 
 - Request one rpc
 
-    ```
+    ```cpp
     ServerContext context;
     HelloRequest request;
     ServerAsyncResponseWriter<HelloReply> responder;
@@ -224,7 +224,7 @@ completion queue to return the tag. The basic flow is
 - Wait for the completion queue to return the tag. The context, request and
   responder are ready once the tag is retrieved.
 
-    ```
+    ```cpp
     HelloReply reply;
     Status status;
     void* got_tag;
@@ -239,7 +239,7 @@ completion queue to return the tag. The basic flow is
 - Wait for the completion queue to return the tag. The rpc is finished when the
   tag is back.
 
-    ```
+    ```cpp
     void* got_tag;
     bool ok = false;
     cq.Next(&got_tag, &ok);

examples/objective-c/auth_sample/AuthTestService.podspec

@@ -29,7 +29,7 @@ Pod::Spec.new do |s|
     ss.source_files = "#{dir}/*.pbrpc.{h,m}", "#{dir}/**/*.pbrpc.{h,m}"
     ss.header_mappings_dir = dir
     ss.requires_arc = true
-    ss.dependency "gRPC", "~> 0.11"
+    ss.dependency "gRPC", "~> 0.12"
     ss.dependency "#{s.name}/Messages"
   end
 end

examples/objective-c/auth_sample/Podfile

@@ -2,6 +2,7 @@ source 'https://github.com/CocoaPods/Specs.git'
 platform :ios, '8.0'
 
 pod 'Protobuf', :path => "../../../third_party/protobuf"
+pod 'BoringSSL', :podspec => "../../../src/objective-c"
 pod 'gRPC', :path => "../../.."
 
 target 'AuthSample' do

examples/objective-c/helloworld/HelloWorld.podspec

@@ -29,7 +29,7 @@ Pod::Spec.new do |s|
     ss.source_files = "#{dir}/*.pbrpc.{h,m}", "#{dir}/**/*.pbrpc.{h,m}"
     ss.header_mappings_dir = dir
     ss.requires_arc = true
-    ss.dependency "gRPC", "~> 0.11"
+    ss.dependency "gRPC", "~> 0.12"
     ss.dependency "#{s.name}/Messages"
   end
 end

examples/objective-c/helloworld/Podfile

@@ -2,6 +2,7 @@ source 'https://github.com/CocoaPods/Specs.git'
 platform :ios, '8.0'
 
 pod 'Protobuf', :path => "../../../third_party/protobuf"
+pod 'BoringSSL', :podspec => "../../../src/objective-c"
 pod 'gRPC', :path => "../../.."
 
 target 'HelloWorld' do

examples/objective-c/route_guide/Podfile

@@ -3,6 +3,7 @@ platform :ios, '8.0'
 
 target 'RouteGuideClient' do
   pod 'Protobuf', :path => "../../../third_party/protobuf"
+  pod 'BoringSSL', :podspec => "../../../src/objective-c"
   pod 'gRPC', :path => "../../.."
   # Depend on the generated RouteGuide library.
   pod 'RouteGuide', :path => '.'

examples/objective-c/route_guide/RouteGuide.podspec

@@ -29,7 +29,7 @@ Pod::Spec.new do |s|
     ss.source_files = "#{dir}/*.pbrpc.{h,m}", "#{dir}/**/*.pbrpc.{h,m}"
     ss.header_mappings_dir = dir
     ss.requires_arc = true
-    ss.dependency "gRPC", "~> 0.11"
+    ss.dependency "gRPC", "~> 0.12"
     ss.dependency "#{s.name}/Messages"
   end
 end

gRPC.podspec

@@ -36,7 +36,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC'
-  version = '0.11.2'
+  version = '0.12.0'
   s.version  = version
   s.summary  = 'gRPC client library for iOS/OSX'
   s.homepage = 'http://www.grpc.io'
@@ -165,7 +165,6 @@ Pod::Spec.new do |s|
                       'src/core/channel/context.h',
                       'src/core/channel/http_client_filter.h',
                       'src/core/channel/http_server_filter.h',
-                      'src/core/channel/noop_filter.h',
                       'src/core/channel/subchannel_call_holder.h',
                       'src/core/client_config/client_config.h',
                       'src/core/client_config/connector.h',
@@ -182,9 +181,8 @@ Pod::Spec.new do |s|
                       'src/core/client_config/resolvers/sockaddr_resolver.h',
                       'src/core/client_config/subchannel.h',
                       'src/core/client_config/subchannel_factory.h',
-                      'src/core/client_config/subchannel_factory_decorators/add_channel_arg.h',
-                      'src/core/client_config/subchannel_factory_decorators/merge_channel_args.h',
                       'src/core/client_config/uri_parser.h',
+                      'src/core/compression/algorithm_metadata.h',
                       'src/core/compression/message_compress.h',
                       'src/core/debug/trace.h',
                       'src/core/httpcli/format_request.h',
@@ -267,6 +265,7 @@ Pod::Spec.new do |s|
                       'src/core/transport/connectivity_state.h',
                       'src/core/transport/metadata.h',
                       'src/core/transport/metadata_batch.h',
+                      'src/core/transport/static_metadata.h',
                       'src/core/transport/transport.h',
                       'src/core/transport/transport_impl.h',
                       'src/core/census/aggregation.h',
@@ -310,7 +309,6 @@ Pod::Spec.new do |s|
                       'src/core/channel/connected_channel.c',
                       'src/core/channel/http_client_filter.c',
                       'src/core/channel/http_server_filter.c',
-                      'src/core/channel/noop_filter.c',
                       'src/core/channel/subchannel_call_holder.c',
                       'src/core/client_config/client_config.c',
                       'src/core/client_config/connector.c',
@@ -328,8 +326,6 @@ Pod::Spec.new do |s|
                       'src/core/client_config/resolvers/sockaddr_resolver.c',
                       'src/core/client_config/subchannel.c',
                       'src/core/client_config/subchannel_factory.c',
-                      'src/core/client_config/subchannel_factory_decorators/add_channel_arg.c',
-                      'src/core/client_config/subchannel_factory_decorators/merge_channel_args.c',
                       'src/core/client_config/uri_parser.c',
                       'src/core/compression/algorithm.c',
                       'src/core/compression/message_compress.c',
@@ -390,6 +386,7 @@ Pod::Spec.new do |s|
                       'src/core/surface/channel.c',
                       'src/core/surface/channel_connectivity.c',
                       'src/core/surface/channel_create.c',
+                      'src/core/surface/channel_ping.c',
                       'src/core/surface/completion_queue.c',
                       'src/core/surface/event_string.c',
                       'src/core/surface/init.c',
@@ -424,6 +421,7 @@ Pod::Spec.new do |s|
                       'src/core/transport/connectivity_state.c',
                       'src/core/transport/metadata.c',
                       'src/core/transport/metadata_batch.c',
+                      'src/core/transport/static_metadata.c',
                       'src/core/transport/transport.c',
                       'src/core/transport/transport_op_string.c',
                       'src/core/census/context.c',
@@ -464,7 +462,6 @@ Pod::Spec.new do |s|
                               'src/core/channel/context.h',
                               'src/core/channel/http_client_filter.h',
                               'src/core/channel/http_server_filter.h',
-                              'src/core/channel/noop_filter.h',
                               'src/core/channel/subchannel_call_holder.h',
                               'src/core/client_config/client_config.h',
                               'src/core/client_config/connector.h',
@@ -481,9 +478,8 @@ Pod::Spec.new do |s|
                               'src/core/client_config/resolvers/sockaddr_resolver.h',
                               'src/core/client_config/subchannel.h',
                               'src/core/client_config/subchannel_factory.h',
-                              'src/core/client_config/subchannel_factory_decorators/add_channel_arg.h',
-                              'src/core/client_config/subchannel_factory_decorators/merge_channel_args.h',
                               'src/core/client_config/uri_parser.h',
+                              'src/core/compression/algorithm_metadata.h',
                               'src/core/compression/message_compress.h',
                               'src/core/debug/trace.h',
                               'src/core/httpcli/format_request.h',
@@ -566,6 +562,7 @@ Pod::Spec.new do |s|
                               'src/core/transport/connectivity_state.h',
                               'src/core/transport/metadata.h',
                               'src/core/transport/metadata_batch.h',
+                              'src/core/transport/static_metadata.h',
                               'src/core/transport/transport.h',
                               'src/core/transport/transport_impl.h',
                               'src/core/census/aggregation.h',
@@ -584,7 +581,7 @@ Pod::Spec.new do |s|
 
     ss.requires_arc = false
     ss.libraries = 'z'
-    ss.dependency 'OpenSSL', '~> 1.0.200'
+    ss.dependency 'BoringSSL', '~> 1.0'
 
     # ss.compiler_flags = '-GCC_WARN_INHIBIT_ALL_WARNINGS', '-w'
   end

include/grpc++/client_context.h

@@ -268,7 +268,7 @@ class ClientContext {
   /// \return The call's peer URI.
   grpc::string peer() const;
 
-  /// Get and set census context
+  /// Get and set census context.
   void set_census_context(struct census_context* ccp) { census_context_ = ccp; }
   struct census_context* census_context() const {
     return census_context_;
@@ -280,6 +280,17 @@ class ClientContext {
   /// There is no guarantee the call will be cancelled.
   void TryCancel();
 
+  /// Global Callbacks
+  ///
+  /// Can be set exactly once per application to install hooks whenever
+  /// a client context is constructed and destructed.
+  class GlobalCallbacks {
+   public:
+    virtual void DefaultConstructor(ClientContext* context) = 0;
+    virtual void Destructor(ClientContext* context) = 0;
+  };
+  static void SetGlobalCallbacks(GlobalCallbacks* callbacks);
+
  private:
   // Disallow copy and assign.
   ClientContext(const ClientContext&);

include/grpc++/impl/rpc_service_method.h

@@ -34,6 +34,7 @@
 #ifndef GRPCXX_IMPL_RPC_SERVICE_METHOD_H
 #define GRPCXX_IMPL_RPC_SERVICE_METHOD_H
 
+#include <climits>
 #include <functional>
 #include <map>
 #include <memory>
@@ -251,7 +252,11 @@ class RpcService {
   void AddMethod(RpcServiceMethod* method) { methods_.emplace_back(method); }
 
   RpcServiceMethod* GetMethod(int i) { return methods_[i].get(); }
-  int GetMethodCount() const { return methods_.size(); }
+  int GetMethodCount() const {
+    // On win x64, int is only 32bit
+    GPR_ASSERT(methods_.size() <= INT_MAX);
+    return (int)methods_.size();
+  }
 
  private:
   std::vector<std::unique_ptr<RpcServiceMethod>> methods_;

src/core/client_config/subchannel_factory_decorators/add_channel_arg.h → include/grpc++/impl/server_builder_option.h

@@ -31,16 +31,21 @@
  *
  */
 
-#ifndef GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_ADD_CHANNEL_ARG_H
-#define GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_ADD_CHANNEL_ARG_H
+#ifndef GRPCXX_IMPL_SERVER_BUILDER_OPTION_H
+#define GRPCXX_IMPL_SERVER_BUILDER_OPTION_H
 
-#include "src/core/client_config/subchannel_factory.h"
+#include <grpc++/support/channel_arguments.h>
 
-/** Takes a subchannel factory, returns a new one that mutates incoming
-    channel_args by adding a new argument; ownership of input, arg is retained
-    by the caller. */
-grpc_subchannel_factory *grpc_subchannel_factory_add_channel_arg(
-    grpc_subchannel_factory *input, const grpc_arg *arg);
+namespace grpc {
 
-#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_ADD_CHANNEL_ARG_H \
-        */
+/// Interface to pass an option to a \a ServerBuilder.
+class ServerBuilderOption {
+ public:
+  virtual ~ServerBuilderOption() {}
+  /// Alter the \a ChannelArguments used to create the gRPC server.
+  virtual void UpdateArguments(ChannelArguments* args) = 0;
+};
+
+}  // namespace grpc
+
+#endif  // GRPCXX_IMPL_SERVER_BUILDER_OPTION_H

include/grpc++/security/credentials.h

@@ -38,6 +38,7 @@
 #include <memory>
 
 #include <grpc++/impl/grpc_library.h>
+#include <grpc++/security/auth_context.h>
 #include <grpc++/support/config.h>
 #include <grpc++/support/status.h>
 #include <grpc++/support/string_ref.h>
@@ -206,9 +207,17 @@ class MetadataCredentialsPlugin {
   // a different thread from the one processing the call.
   virtual bool IsBlocking() const { return true; }
 
+  // Type of credentials this plugin is implementing.
+  virtual const char* GetType() const { return ""; }
+
   // Gets the auth metatada produced by this plugin.
+  // The fully qualified method name is:
+  // service_url + "/" + method_name.
+  // The channel_auth_context contains (among other things), the identity of
+  // the server.
   virtual Status GetMetadata(
-      grpc::string_ref service_url,
+      grpc::string_ref service_url, grpc::string_ref method_name,
+      const AuthContext& channel_auth_context,
       std::multimap<grpc::string, grpc::string>* metadata) = 0;
 };
 

include/grpc++/server.h

@@ -37,14 +37,15 @@
 #include <list>
 #include <memory>
 
-#include <grpc/compression.h>
 #include <grpc++/completion_queue.h>
 #include <grpc++/impl/call.h>
 #include <grpc++/impl/grpc_library.h>
 #include <grpc++/impl/sync.h>
 #include <grpc++/security/server_credentials.h>
+#include <grpc++/support/channel_arguments.h>
 #include <grpc++/support/config.h>
 #include <grpc++/support/status.h>
+#include <grpc/compression.h>
 
 struct grpc_server;
 
@@ -56,6 +57,7 @@ class AsyncGenericService;
 class RpcService;
 class RpcServiceMethod;
 class ServerAsyncStreamingInterface;
+class ServerContext;
 class ThreadPoolInterface;
 
 /// Models a gRPC server.
@@ -84,6 +86,23 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
   /// call \a Shutdown for this function to ever return.
   void Wait();
 
+  /// Global Callbacks
+  ///
+  /// Can be set exactly once per application to install hooks whenever
+  /// a server event occurs
+  class GlobalCallbacks {
+   public:
+    virtual ~GlobalCallbacks() {}
+    /// Called before application callback for each synchronous server request
+    virtual void PreSynchronousRequest(ServerContext* context) = 0;
+    /// Called after application callback for each synchronous server request
+    virtual void PostSynchronousRequest(ServerContext* context) = 0;
+  };
+  /// Set the global callback object. Can only be called once. Does not take
+  /// ownership of callbacks, and expects the pointed to object to be alive
+  /// until all server objects in the process have been destroyed.
+  static void SetGlobalCallbacks(GlobalCallbacks* callbacks);
+
  private:
   friend class AsyncGenericService;
   friend class AsynchronousService;
@@ -100,7 +119,7 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
   /// \param max_message_size Maximum message length that the channel can
   /// receive.
   Server(ThreadPoolInterface* thread_pool, bool thread_pool_owned,
-         int max_message_size, grpc_compression_options compression_options);
+         int max_message_size, const ChannelArguments& args);
 
   /// Register a service. This call does not take ownership of the service.
   /// The service must exist for the lifetime of the Server instance.

include/grpc++/server_builder.h

@@ -37,8 +37,9 @@
 #include <memory>
 #include <vector>
 
-#include <grpc/compression.h>
+#include <grpc++/impl/server_builder_option.h>
 #include <grpc++/support/config.h>
+#include <grpc/compression.h>
 
 namespace grpc {
 
@@ -98,6 +99,8 @@ class ServerBuilder {
     compression_options_ = options;
   }
 
+  void SetOption(std::unique_ptr<ServerBuilderOption> option);
+
   /// Tries to bind \a server to the given \a addr.
   ///
   /// It can be invoked multiple times.
@@ -140,6 +143,7 @@ class ServerBuilder {
 
   int max_message_size_;
   grpc_compression_options compression_options_;
+  std::vector<std::unique_ptr<ServerBuilderOption>> options_;
   std::vector<std::unique_ptr<NamedService<RpcService>>> services_;
   std::vector<std::unique_ptr<NamedService<AsynchronousService>>>
       async_services_;

include/grpc++/support/channel_arguments.h

@@ -80,6 +80,11 @@ class ChannelArguments {
   // Generic channel argument setters. Only for advanced use cases.
   /// Set an integer argument \a value under \a key.
   void SetInt(const grpc::string& key, int value);
+
+  // Generic channel argument setter. Only for advanced use cases.
+  /// Set a pointer argument \a value under \a key. Owership is not transferred.
+  void SetPointer(const grpc::string& key, void* value);
+
   /// Set a textual argument \a value under \a key.
   void SetString(const grpc::string& key, const grpc::string& value);
 

include/grpc/compression.h

@@ -79,12 +79,6 @@ int grpc_compression_algorithm_parse(const char *name, size_t name_length,
 int grpc_compression_algorithm_name(grpc_compression_algorithm algorithm,
                                     char **name);
 
-/** Returns the compression level corresponding to \a algorithm.
- *
- * It abort()s for unknown algorithms. */
-grpc_compression_level grpc_compression_level_for_algorithm(
-    grpc_compression_algorithm algorithm);
-
 /** Returns the compression algorithm corresponding to \a level.
  *
  * It abort()s for unknown levels . */

include/grpc/grpc.h

@@ -531,6 +531,11 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
                                     const char *method, const char *host,
                                     gpr_timespec deadline, void *reserved);
 
+/** Ping the channels peer (load balanced channels will select one sub-channel
+    to ping); if the channel is not connected, posts a failed. */
+void grpc_channel_ping(grpc_channel *channel, grpc_completion_queue *cq,
+                       void *tag, void *reserved);
+
 /** Pre-register a method/host pair on a channel. */
 void *grpc_channel_register_call(grpc_channel *channel, const char *method,
                                  const char *host, void *reserved);

include/grpc/grpc_security.h

@@ -41,6 +41,81 @@
 extern "C" {
 #endif
 
+/* --- Authentication Context. --- */
+
+#define GRPC_TRANSPORT_SECURITY_TYPE_PROPERTY_NAME "transport_security_type"
+#define GRPC_SSL_TRANSPORT_SECURITY_TYPE "ssl"
+
+#define GRPC_X509_CN_PROPERTY_NAME "x509_common_name"
+#define GRPC_X509_SAN_PROPERTY_NAME "x509_subject_alternative_name"
+
+typedef struct grpc_auth_context grpc_auth_context;
+
+typedef struct grpc_auth_property_iterator {
+  const grpc_auth_context *ctx;
+  size_t index;
+  const char *name;
+} grpc_auth_property_iterator;
+
+/* value, if not NULL, is guaranteed to be NULL terminated. */
+typedef struct grpc_auth_property {
+  char *name;
+  char *value;
+  size_t value_length;
+} grpc_auth_property;
+
+/* Returns NULL when the iterator is at the end. */
+const grpc_auth_property *grpc_auth_property_iterator_next(
+    grpc_auth_property_iterator *it);
+
+/* Iterates over the auth context. */
+grpc_auth_property_iterator grpc_auth_context_property_iterator(
+    const grpc_auth_context *ctx);
+
+/* Gets the peer identity. Returns an empty iterator (first _next will return
+   NULL) if the peer is not authenticated. */
+grpc_auth_property_iterator grpc_auth_context_peer_identity(
+    const grpc_auth_context *ctx);
+
+/* Finds a property in the context. May return an empty iterator (first _next
+   will return NULL) if no property with this name was found in the context. */
+grpc_auth_property_iterator grpc_auth_context_find_properties_by_name(
+    const grpc_auth_context *ctx, const char *name);
+
+/* Gets the name of the property that indicates the peer identity. Will return
+   NULL if the peer is not authenticated. */
+const char *grpc_auth_context_peer_identity_property_name(
+    const grpc_auth_context *ctx);
+
+/* Returns 1 if the peer is authenticated, 0 otherwise. */
+int grpc_auth_context_peer_is_authenticated(const grpc_auth_context *ctx);
+
+/* Gets the auth context from the call. Caller needs to call
+   grpc_auth_context_release on the returned context. */
+grpc_auth_context *grpc_call_auth_context(grpc_call *call);
+
+/* Releases the auth context returned from grpc_call_auth_context. */
+void grpc_auth_context_release(grpc_auth_context *context);
+
+/* --
+   The following auth context methods should only be called by a server metadata
+   processor to set properties extracted from auth metadata.
+   -- */
+
+/* Add a property. */
+void grpc_auth_context_add_property(grpc_auth_context *ctx, const char *name,
+                                    const char *value, size_t value_length);
+
+/* Add a C string property. */
+void grpc_auth_context_add_cstring_property(grpc_auth_context *ctx,
+                                            const char *name,
+                                            const char *value);
+
+/* Sets the property name. Returns 1 if successful or 0 in case of failure
+   (which means that no property with this name exists). */
+int grpc_auth_context_set_peer_identity_property_name(grpc_auth_context *ctx,
+                                                      const char *name);
+
 /* --- grpc_channel_credentials object. ---
 
    A channel credentials object represents a way to authenticate a client on a
@@ -165,6 +240,24 @@ typedef void (*grpc_credentials_plugin_metadata_cb)(
     void *user_data, const grpc_metadata *creds_md, size_t num_creds_md,
     grpc_status_code status, const char *error_details);
 
+/* Context that can be used by metadata credentials plugin in order to create
+   auth related metadata. */
+typedef struct {
+  /* The fully qualifed service url. */
+  const char *service_url;
+
+  /* The method name of the RPC being called (not fully qualified).
+     The fully qualified method name can be built from the service_url:
+     full_qualified_method_name = ctx->service_url + '/' + ctx->method_name. */
+  const char *method_name;
+
+  /* The auth_context of the channel which gives the server's identity. */
+  const grpc_auth_context *channel_auth_context;
+
+  /* Reserved for future use. */
+  void *reserved;
+} grpc_auth_metadata_context;
+
 /* grpc_metadata_credentials plugin is an API user provided structure used to
    create grpc_credentials objects that can be set on a channel (composed) or
    a call. See grpc_credentials_metadata_create_from_plugin below.
@@ -172,11 +265,11 @@ typedef void (*grpc_credentials_plugin_metadata_cb)(
    every call in scope for the credentials created from it. */
 typedef struct {
   /* The implementation of this method has to be non-blocking.
-     - service_url is the fully qualified URL that the client stack is
-       connecting to.
+     - context is the information that can be used by the plugin to create auth
+       metadata.
      - cb is the callback that needs to be called when the metadata is ready.
      - user_data needs to be passed as the first parameter of the callback. */
-  void (*get_metadata)(void *state, const char *service_url,
+  void (*get_metadata)(void *state, grpc_auth_metadata_context context,
                        grpc_credentials_plugin_metadata_cb cb, void *user_data);
 
   /* Destroys the plugin state. */
@@ -184,6 +277,9 @@ typedef struct {
 
   /* State that will be set as the first parameter of the methods above. */
   void *state;
+
+  /* Type of credentials that this plugin is implementing. */
+  const char *type;
 } grpc_metadata_credentials_plugin;
 
 /* Creates a credentials object from a plugin. */
@@ -239,81 +335,6 @@ int grpc_server_add_secure_http2_port(grpc_server *server, const char *addr,
 grpc_call_error grpc_call_set_credentials(grpc_call *call,
                                           grpc_call_credentials *creds);
 
-/* --- Authentication Context. --- */
-
-#define GRPC_TRANSPORT_SECURITY_TYPE_PROPERTY_NAME "transport_security_type"
-#define GRPC_SSL_TRANSPORT_SECURITY_TYPE "ssl"
-
-#define GRPC_X509_CN_PROPERTY_NAME "x509_common_name"
-#define GRPC_X509_SAN_PROPERTY_NAME "x509_subject_alternative_name"
-
-typedef struct grpc_auth_context grpc_auth_context;
-
-typedef struct grpc_auth_property_iterator {
-  const grpc_auth_context *ctx;
-  size_t index;
-  const char *name;
-} grpc_auth_property_iterator;
-
-/* value, if not NULL, is guaranteed to be NULL terminated. */
-typedef struct grpc_auth_property {
-  char *name;
-  char *value;
-  size_t value_length;
-} grpc_auth_property;
-
-/* Returns NULL when the iterator is at the end. */
-const grpc_auth_property *grpc_auth_property_iterator_next(
-    grpc_auth_property_iterator *it);
-
-/* Iterates over the auth context. */
-grpc_auth_property_iterator grpc_auth_context_property_iterator(
-    const grpc_auth_context *ctx);
-
-/* Gets the peer identity. Returns an empty iterator (first _next will return
-   NULL) if the peer is not authenticated. */
-grpc_auth_property_iterator grpc_auth_context_peer_identity(
-    const grpc_auth_context *ctx);
-
-/* Finds a property in the context. May return an empty iterator (first _next
-   will return NULL) if no property with this name was found in the context. */
-grpc_auth_property_iterator grpc_auth_context_find_properties_by_name(
-    const grpc_auth_context *ctx, const char *name);
-
-/* Gets the name of the property that indicates the peer identity. Will return
-   NULL if the peer is not authenticated. */
-const char *grpc_auth_context_peer_identity_property_name(
-    const grpc_auth_context *ctx);
-
-/* Returns 1 if the peer is authenticated, 0 otherwise. */
-int grpc_auth_context_peer_is_authenticated(const grpc_auth_context *ctx);
-
-/* Gets the auth context from the call. Caller needs to call
-   grpc_auth_context_release on the returned context. */
-grpc_auth_context *grpc_call_auth_context(grpc_call *call);
-
-/* Releases the auth context returned from grpc_call_auth_context. */
-void grpc_auth_context_release(grpc_auth_context *context);
-
-/* --
-   The following auth context methods should only be called by a server metadata
-   processor to set properties extracted from auth metadata.
-   -- */
-
-/* Add a property. */
-void grpc_auth_context_add_property(grpc_auth_context *ctx, const char *name,
-                                    const char *value, size_t value_length);
-
-/* Add a C string property. */
-void grpc_auth_context_add_cstring_property(grpc_auth_context *ctx,
-                                            const char *name,
-                                            const char *value);
-
-/* Sets the property name. Returns 1 if successful or 0 in case of failure
-   (which means that no property with this name exists). */
-int grpc_auth_context_set_peer_identity_property_name(grpc_auth_context *ctx,
-                                                      const char *name);
-
 /* --- Auth Metadata Processing --- */
 
 /* Callback function that is called when the metadata processing is done.

include/grpc/support/alloc.h

@@ -40,6 +40,12 @@
 extern "C" {
 #endif
 
+typedef struct gpr_allocation_functions {
+  void *(*malloc_fn)(size_t size);
+  void *(*realloc_fn)(void *ptr, size_t size);
+  void (*free_fn)(void *ptr);
+} gpr_allocation_functions;
+
 /* malloc, never returns NULL */
 void *gpr_malloc(size_t size);
 /* free */
@@ -51,6 +57,14 @@ void *gpr_malloc_aligned(size_t size, size_t alignment_log);
 /* free memory allocated by gpr_malloc_aligned */
 void gpr_free_aligned(void *ptr);
 
+/** Request the family of allocation functions in \a functions be used. NOTE
+ * that this request will be honored in a *best effort* basis and that no
+ * guarantees are made about the default functions (eg, malloc) being called. */
+void gpr_set_allocation_functions(gpr_allocation_functions functions);
+
+/** Return the family of allocation functions currently in effect. */
+gpr_allocation_functions gpr_get_allocation_functions();
+
 #ifdef __cplusplus
 }
 #endif

include/grpc/support/cmdline.h

@@ -83,8 +83,12 @@ void gpr_cmdline_add_string(gpr_cmdline *cl, const char *name, const char *help,
 void gpr_cmdline_on_extra_arg(
     gpr_cmdline *cl, const char *name, const char *help,
     void (*on_extra_arg)(void *user_data, const char *arg), void *user_data);
-/* Parse the command line */
-void gpr_cmdline_parse(gpr_cmdline *cl, int argc, char **argv);
+/* Enable surviving failure: default behavior is to exit the process */
+void gpr_cmdline_set_survive_failure(gpr_cmdline *cl);
+/* Parse the command line; returns 1 on success, on failure either dies
+   (by default) or returns 0 if gpr_cmdline_set_survive_failure() has been
+   called */
+int gpr_cmdline_parse(gpr_cmdline *cl, int argc, char **argv);
 /* Destroy the parser */
 void gpr_cmdline_destroy(gpr_cmdline *cl);
 /* Get a string describing usage */

include/grpc/support/port_platform.h

@@ -183,7 +183,7 @@
 #endif
 #define GPR_MSG_IOVLEN_TYPE int
 #if TARGET_OS_IPHONE
-#define GPR_FORBID_UNREACHABLE_CODE
+#define GPR_FORBID_UNREACHABLE_CODE 1
 #define GPR_PLATFORM_STRING "ios"
 #define GPR_CPU_IPHONE 1
 #define GPR_PTHREAD_TLS 1
@@ -252,6 +252,11 @@
 #define GPR_PLATFORM_STRING "unknown"
 #endif
 
+#ifdef GPR_GCOV
+#undef GPR_FORBID_UNREACHABLE_CODE
+#define GPR_FORBID_UNREACHABLE_CODE 1
+#endif
+
 /* For a common case, assume that the platform has a C99-like stdint.h */
 
 #include <stdint.h>
@@ -337,7 +342,7 @@ typedef uintptr_t gpr_uintptr;
 #endif
 #endif
 
-#ifdef GPR_FORBID_UNREACHABLE_CODE
+#if GPR_FORBID_UNREACHABLE_CODE
 #define GPR_UNREACHABLE_CODE(STATEMENT)
 #else
 #define GPR_UNREACHABLE_CODE(STATEMENT)             \

include/grpc/support/slice.h

@@ -144,6 +144,9 @@ gpr_slice gpr_slice_from_copied_string(const char *source);
      memcpy(slice->data, source, len); */
 gpr_slice gpr_slice_from_copied_buffer(const char *source, size_t len);
 
+/* Create a slice pointing to constant memory */
+gpr_slice gpr_slice_from_static_string(const char *source);
+
 /* Return a result slice derived from s, which shares a ref count with s, where
    result.data==s.data+begin, and result.length==end-begin.
    The ref count of s is increased by one.

include/grpc/support/time.h

@@ -61,8 +61,8 @@ typedef enum {
 } gpr_clock_type;
 
 typedef struct gpr_timespec {
-  time_t tv_sec;
-  int tv_nsec;
+  gpr_int64 tv_sec;
+  gpr_int32 tv_nsec;
   /** Against which clock was this time measured? (or GPR_TIMESPAN if
       this is a relative time meaure) */
   gpr_clock_type clock_type;

package.json

@@ -1,6 +1,6 @@
 {
   "name": "grpc",
-  "version": "0.11.1",
+  "version": "0.12.0",
   "author": "Google Inc.",
   "description": "gRPC Library for Node",
   "homepage": "http://www.grpc.io/",
@@ -39,7 +39,8 @@
     "minimist": "^1.1.0",
     "mocha": "~1.21.0",
     "mocha-jenkins-reporter": "^0.1.9",
-    "mustache": "^2.0.0"
+    "mustache": "^2.0.0",
+    "poisson-process": "^0.2.1"
   },
   "engines": {
     "node": ">=0.10.13"

src/core/census/context.h

@@ -36,14 +36,12 @@
 
 #include <grpc/census.h>
 
+#define GRPC_CENSUS_MAX_ON_THE_WIRE_TAG_BYTES 2048
+
 /* census_context is the in-memory representation of information needed to
  * maintain tracing, RPC statistics and resource usage information. */
 struct census_context {
-  gpr_uint64 op_id;    /* Operation identifier - unique per-context */
-  gpr_uint64 trace_id; /* Globally unique trace identifier */
-                       /* TODO(aveitch) Add census tags:
-                          const census_tag_set *tags;
-                        */
+  census_tag_set *tags; /* Opaque data structure for census tags. */
 };
 
 #endif /* GRPC_INTERNAL_CORE_CENSUS_CONTEXT_H */

src/core/census/grpc_filter.c

@@ -36,16 +36,17 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "src/core/channel/channel_stack.h"
-#include "src/core/channel/noop_filter.h"
-#include "src/core/statistics/census_interface.h"
-#include "src/core/statistics/census_rpc_stats.h"
 #include <grpc/census.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/slice.h>
 #include <grpc/support/time.h>
 
+#include "src/core/channel/channel_stack.h"
+#include "src/core/statistics/census_interface.h"
+#include "src/core/statistics/census_rpc_stats.h"
+#include "src/core/transport/static_metadata.h"
+
 typedef struct call_data {
   census_op_id op_id;
   census_context *ctxt;
@@ -58,16 +59,14 @@ typedef struct call_data {
   grpc_closure finish_recv;
 } call_data;
 
-typedef struct channel_data {
-  grpc_mdstr *path_str; /* pointer to meta data str with key == ":path" */
-} channel_data;
+typedef struct channel_data { gpr_uint8 unused; } channel_data;
 
 static void extract_and_annotate_method_tag(grpc_metadata_batch *md,
                                             call_data *calld,
                                             channel_data *chand) {
   grpc_linked_mdelem *m;
   for (m = md->list.head; m != NULL; m = m->next) {
-    if (m->md->key == chand->path_str) {
+    if (m->md->key == GRPC_MDSTR_PATH) {
       gpr_log(GPR_DEBUG, "%s",
               (const char *)GPR_SLICE_START_PTR(m->md->value->slice));
       /* Add method tag here */
@@ -116,8 +115,11 @@ static void server_mutate_op(grpc_call_element *elem,
 static void server_start_transport_op(grpc_exec_ctx *exec_ctx,
                                       grpc_call_element *elem,
                                       grpc_transport_stream_op *op) {
+  /* TODO(ctiller): this code fails. I don't know why. I expect it's
+                    incomplete, and someone should look at it soon.
+
   call_data *calld = elem->call_data;
-  GPR_ASSERT((calld->op_id.upper != 0) || (calld->op_id.lower != 0));
+  GPR_ASSERT((calld->op_id.upper != 0) || (calld->op_id.lower != 0)); */
   server_mutate_op(elem, op);
   grpc_call_next_op(exec_ctx, elem, op);
 }
@@ -161,16 +163,12 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
                               grpc_channel_element_args *args) {
   channel_data *chand = elem->channel_data;
   GPR_ASSERT(chand != NULL);
-  chand->path_str = grpc_mdstr_from_string(args->metadata_context, ":path");
 }
 
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                  grpc_channel_element *elem) {
   channel_data *chand = elem->channel_data;
   GPR_ASSERT(chand != NULL);
-  if (chand->path_str != NULL) {
-    GRPC_MDSTR_UNREF(chand->path_str);
-  }
 }
 
 const grpc_channel_filter grpc_client_census_filter = {

src/core/channel/channel_stack.c

@@ -101,12 +101,12 @@ grpc_call_element *grpc_call_stack_element(grpc_call_stack *call_stack,
   return CALL_ELEMS_FROM_STACK(call_stack) + index;
 }
 
-void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx,
+void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx, int initial_refs,
+                             grpc_iomgr_cb_func destroy, void *destroy_arg,
                              const grpc_channel_filter **filters,
-                             size_t filter_count, grpc_channel *master,
+                             size_t filter_count,
                              const grpc_channel_args *channel_args,
-                             grpc_mdctx *metadata_context,
-                             grpc_channel_stack *stack) {
+                             const char *name, grpc_channel_stack *stack) {
   size_t call_size =
       ROUND_UP_TO_ALIGNMENT_SIZE(sizeof(grpc_call_stack)) +
       ROUND_UP_TO_ALIGNMENT_SIZE(filter_count * sizeof(grpc_call_element));
@@ -116,6 +116,8 @@ void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx,
   size_t i;
 
   stack->count = filter_count;
+  GRPC_STREAM_REF_INIT(&stack->refcount, initial_refs, destroy, destroy_arg,
+                       name);
   elems = CHANNEL_ELEMS_FROM_STACK(stack);
   user_data =
       ((char *)elems) +
@@ -123,9 +125,8 @@ void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx,
 
   /* init per-filter data */
   for (i = 0; i < filter_count; i++) {
-    args.master = master;
+    args.channel_stack = stack;
     args.channel_args = channel_args;
-    args.metadata_context = metadata_context;
     args.is_first = i == 0;
     args.is_last = i == (filter_count - 1);
     elems[i].filter = filters[i];
@@ -168,15 +169,15 @@ void grpc_call_stack_init(grpc_exec_ctx *exec_ctx,
   size_t i;
 
   call_stack->count = count;
-  gpr_ref_init(&call_stack->refcount.refs, initial_refs);
-  grpc_closure_init(&call_stack->refcount.destroy, destroy, destroy_arg);
+  GRPC_STREAM_REF_INIT(&call_stack->refcount, initial_refs, destroy,
+                       destroy_arg, "CALL_STACK");
   call_elems = CALL_ELEMS_FROM_STACK(call_stack);
   user_data = ((char *)call_elems) +
               ROUND_UP_TO_ALIGNMENT_SIZE(count * sizeof(grpc_call_element));
 
   /* init per-filter data */
   for (i = 0; i < count; i++) {
-    args.refcount = &call_stack->refcount;
+    args.call_stack = call_stack;
     args.server_transport_data = transport_server_data;
     args.context = context;
     call_elems[i].filter = channel_elems[i].filter;

src/core/channel/channel_stack.h

@@ -51,16 +51,18 @@
 typedef struct grpc_channel_element grpc_channel_element;
 typedef struct grpc_call_element grpc_call_element;
 
+typedef struct grpc_channel_stack grpc_channel_stack;
+typedef struct grpc_call_stack grpc_call_stack;
+
 typedef struct {
-  grpc_channel *master;
+  grpc_channel_stack *channel_stack;
   const grpc_channel_args *channel_args;
-  grpc_mdctx *metadata_context;
   int is_first;
   int is_last;
 } grpc_channel_element_args;
 
 typedef struct {
-  grpc_stream_refcount *refcount;
+  grpc_call_stack *call_stack;
   const void *server_transport_data;
   grpc_call_context_element *context;
 } grpc_call_element_args;
@@ -145,23 +147,24 @@ struct grpc_call_element {
 
 /* A channel stack tracks a set of related filters for one channel, and
    guarantees they live within a single malloc() allocation */
-typedef struct {
+struct grpc_channel_stack {
+  grpc_stream_refcount refcount;
   size_t count;
   /* Memory required for a call stack (computed at channel stack
      initialization) */
   size_t call_stack_size;
-} grpc_channel_stack;
+};
 
 /* A call stack tracks a set of related filters for one call, and guarantees
    they live within a single malloc() allocation */
-typedef struct {
+struct grpc_call_stack {
   /* shared refcount for this channel stack.
      MUST be the first element: the underlying code calls destroy
      with the address of the refcount, but higher layers prefer to think
      about the address of the call stack itself. */
   grpc_stream_refcount refcount;
   size_t count;
-} grpc_call_stack;
+};
 
 /* Get a channel element given a channel stack and its index */
 grpc_channel_element *grpc_channel_stack_element(grpc_channel_stack *stack,
@@ -176,12 +179,11 @@ grpc_call_element *grpc_call_stack_element(grpc_call_stack *stack, size_t i);
 size_t grpc_channel_stack_size(const grpc_channel_filter **filters,
                                size_t filter_count);
 /* Initialize a channel stack given some filters */
-void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx,
+void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx, int initial_refs,
+                             grpc_iomgr_cb_func destroy, void *destroy_arg,
                              const grpc_channel_filter **filters,
-                             size_t filter_count, grpc_channel *master,
-                             const grpc_channel_args *args,
-                             grpc_mdctx *metadata_context,
-                             grpc_channel_stack *stack);
+                             size_t filter_count, const grpc_channel_args *args,
+                             const char *name, grpc_channel_stack *stack);
 /* Destroy a channel stack */
 void grpc_channel_stack_destroy(grpc_exec_ctx *exec_ctx,
                                 grpc_channel_stack *stack);
@@ -201,14 +203,23 @@ void grpc_call_stack_set_pollset(grpc_exec_ctx *exec_ctx,
                                  grpc_pollset *pollset);
 
 #ifdef GRPC_STREAM_REFCOUNT_DEBUG
-#define grpc_call_stack_ref(call_stack, reason) \
+#define GRPC_CALL_STACK_REF(call_stack, reason) \
   grpc_stream_ref(&(call_stack)->refcount, reason)
-#define grpc_call_stack_unref(exec_ctx, call_stack, reason) \
+#define GRPC_CALL_STACK_UNREF(exec_ctx, call_stack, reason) \
   grpc_stream_unref(exec_ctx, &(call_stack)->refcount, reason)
+#define GRPC_CHANNEL_STACK_REF(channel_stack, reason) \
+  grpc_stream_ref(&(channel_stack)->refcount, reason)
+#define GRPC_CHANNEL_STACK_UNREF(exec_ctx, channel_stack, reason) \
+  grpc_stream_unref(exec_ctx, &(channel_stack)->refcount, reason)
 #else
-#define grpc_call_stack_ref(call_stack) grpc_stream_ref(&(call_stack)->refcount)
-#define grpc_call_stack_unref(exec_ctx, call_stack) \
+#define GRPC_CALL_STACK_REF(call_stack, reason) \
+  grpc_stream_ref(&(call_stack)->refcount)
+#define GRPC_CALL_STACK_UNREF(exec_ctx, call_stack, reason) \
   grpc_stream_unref(exec_ctx, &(call_stack)->refcount)
+#define GRPC_CHANNEL_STACK_REF(channel_stack, reason) \
+  grpc_stream_ref(&(channel_stack)->refcount)
+#define GRPC_CHANNEL_STACK_UNREF(exec_ctx, channel_stack, reason) \
+  grpc_stream_unref(exec_ctx, &(channel_stack)->refcount)
 #endif
 
 /* Destroy a call stack */

src/core/channel/client_channel.c

@@ -55,17 +55,10 @@
 typedef grpc_subchannel_call_holder call_data;
 
 typedef struct client_channel_channel_data {
-  /** metadata context for this channel */
-  grpc_mdctx *mdctx;
   /** resolver for this channel */
   grpc_resolver *resolver;
   /** have we started resolving this channel */
   int started_resolving;
-  /** master channel - the grpc_channel instance that ultimately owns
-      this channel_data via its channel stack.
-      We occasionally use this to bump the refcount on the master channel
-      to keep ourselves alive through an asynchronous operation. */
-  grpc_channel *master;
 
   /** mutex protecting client configuration, including all
       variables below in this data structure */
@@ -83,8 +76,10 @@ typedef struct client_channel_channel_data {
   grpc_connectivity_state_tracker state_tracker;
   /** when an lb_policy arrives, should we try to exit idle */
   int exit_idle_when_lb_policy_arrives;
-  /** pollset_set of interested parties in a new connection */
-  grpc_pollset_set pollset_set;
+  /** owning stack */
+  grpc_channel_stack *owning_stack;
+  /** interested parties */
+  grpc_pollset_set interested_parties;
 } channel_data;
 
 /** We create one watcher for each new lb_policy that is returned from a
@@ -105,9 +100,7 @@ typedef struct {
 } waiting_call;
 
 static char *cc_get_peer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
-  channel_data *chand = elem->channel_data;
-  return grpc_subchannel_call_holder_get_peer(exec_ctx, elem->call_data,
-                                              chand->master);
+  return grpc_subchannel_call_holder_get_peer(exec_ctx, elem->call_data);
 }
 
 static void cc_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
@@ -123,10 +116,18 @@ static void watch_lb_policy(grpc_exec_ctx *exec_ctx, channel_data *chand,
 
 static void on_lb_policy_state_changed_locked(
     grpc_exec_ctx *exec_ctx, lb_policy_connectivity_watcher *w) {
+  grpc_connectivity_state publish_state = w->state;
   /* check if the notification is for a stale policy */
   if (w->lb_policy != w->chand->lb_policy) return;
 
-  grpc_connectivity_state_set(exec_ctx, &w->chand->state_tracker, w->state,
+  if (publish_state == GRPC_CHANNEL_FATAL_FAILURE &&
+      w->chand->resolver != NULL) {
+    publish_state = GRPC_CHANNEL_TRANSIENT_FAILURE;
+    grpc_resolver_channel_saw_error(exec_ctx, w->chand->resolver);
+    GRPC_LB_POLICY_UNREF(exec_ctx, w->chand->lb_policy, "channel");
+    w->chand->lb_policy = NULL;
+  }
+  grpc_connectivity_state_set(exec_ctx, &w->chand->state_tracker, publish_state,
                               "lb_changed");
   if (w->state != GRPC_CHANNEL_FATAL_FAILURE) {
     watch_lb_policy(exec_ctx, w->chand, w->lb_policy, w->state);
@@ -141,7 +142,7 @@ static void on_lb_policy_state_changed(grpc_exec_ctx *exec_ctx, void *arg,
   on_lb_policy_state_changed_locked(exec_ctx, w);
   gpr_mu_unlock(&w->chand->mu_config);
 
-  GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, w->chand->master, "watch_lb_policy");
+  GRPC_CHANNEL_STACK_UNREF(exec_ctx, w->chand->owning_stack, "watch_lb_policy");
   gpr_free(w);
 }
 
@@ -149,7 +150,7 @@ static void watch_lb_policy(grpc_exec_ctx *exec_ctx, channel_data *chand,
                             grpc_lb_policy *lb_policy,
                             grpc_connectivity_state current_state) {
   lb_policy_connectivity_watcher *w = gpr_malloc(sizeof(*w));
-  GRPC_CHANNEL_INTERNAL_REF(chand->master, "watch_lb_policy");
+  GRPC_CHANNEL_STACK_REF(chand->owning_stack, "watch_lb_policy");
 
   w->chand = chand;
   grpc_closure_init(&w->on_changed, on_lb_policy_state_changed, w);
@@ -181,6 +182,11 @@ static void cc_on_config_changed(grpc_exec_ctx *exec_ctx, void *arg,
 
   chand->incoming_configuration = NULL;
 
+  if (lb_policy != NULL) {
+    grpc_pollset_set_add_pollset_set(exec_ctx, &lb_policy->interested_parties,
+                                     &chand->interested_parties);
+  }
+
   gpr_mu_lock(&chand->mu_config);
   old_lb_policy = chand->lb_policy;
   chand->lb_policy = lb_policy;
@@ -202,7 +208,7 @@ static void cc_on_config_changed(grpc_exec_ctx *exec_ctx, void *arg,
       watch_lb_policy(exec_ctx, chand, lb_policy, state);
     }
     gpr_mu_unlock(&chand->mu_config);
-    GRPC_CHANNEL_INTERNAL_REF(chand->master, "resolver");
+    GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
     grpc_resolver_next(exec_ctx, resolver, &chand->incoming_configuration,
                        &chand->on_config_changed);
     GRPC_RESOLVER_UNREF(exec_ctx, resolver, "channel-next");
@@ -224,7 +230,9 @@ static void cc_on_config_changed(grpc_exec_ctx *exec_ctx, void *arg,
   }
 
   if (old_lb_policy != NULL) {
-    grpc_lb_policy_shutdown(exec_ctx, old_lb_policy);
+    grpc_pollset_set_del_pollset_set(exec_ctx,
+                                     &old_lb_policy->interested_parties,
+                                     &chand->interested_parties);
     GRPC_LB_POLICY_UNREF(exec_ctx, old_lb_policy, "channel");
   }
 
@@ -232,20 +240,22 @@ static void cc_on_config_changed(grpc_exec_ctx *exec_ctx, void *arg,
     GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "config_change");
   }
 
-  GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, chand->master, "resolver");
+  GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "resolver");
 }
 
 static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
                                   grpc_channel_element *elem,
                                   grpc_transport_op *op) {
-  grpc_lb_policy *lb_policy = NULL;
   channel_data *chand = elem->channel_data;
   grpc_resolver *destroy_resolver = NULL;
 
   grpc_exec_ctx_enqueue(exec_ctx, op->on_consumed, 1);
 
   GPR_ASSERT(op->set_accept_stream == NULL);
-  GPR_ASSERT(op->bind_pollset == NULL);
+  if (op->bind_pollset != NULL) {
+    grpc_pollset_set_add_pollset(exec_ctx, &chand->interested_parties,
+                                 op->bind_pollset);
+  }
 
   gpr_mu_lock(&chand->mu_config);
   if (op->on_connectivity_state_change != NULL) {
@@ -256,9 +266,14 @@ static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
     op->connectivity_state = NULL;
   }
 
-  lb_policy = chand->lb_policy;
-  if (lb_policy) {
-    GRPC_LB_POLICY_REF(lb_policy, "broadcast");
+  if (op->send_ping != NULL) {
+    if (chand->lb_policy == NULL) {
+      grpc_exec_ctx_enqueue(exec_ctx, op->send_ping, 0);
+    } else {
+      grpc_lb_policy_ping_one(exec_ctx, chand->lb_policy, op->send_ping);
+      op->bind_pollset = NULL;
+    }
+    op->send_ping = NULL;
   }
 
   if (op->disconnect && chand->resolver != NULL) {
@@ -267,7 +282,9 @@ static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
     destroy_resolver = chand->resolver;
     chand->resolver = NULL;
     if (chand->lb_policy != NULL) {
-      grpc_lb_policy_shutdown(exec_ctx, chand->lb_policy);
+      grpc_pollset_set_del_pollset_set(exec_ctx,
+                                       &chand->lb_policy->interested_parties,
+                                       &chand->interested_parties);
       GRPC_LB_POLICY_UNREF(exec_ctx, chand->lb_policy, "channel");
       chand->lb_policy = NULL;
     }
@@ -278,16 +295,11 @@ static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
     grpc_resolver_shutdown(exec_ctx, destroy_resolver);
     GRPC_RESOLVER_UNREF(exec_ctx, destroy_resolver, "channel");
   }
-
-  if (lb_policy) {
-    grpc_lb_policy_broadcast(exec_ctx, lb_policy, op);
-    GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "broadcast");
-  }
 }
 
 typedef struct {
   grpc_metadata_batch *initial_metadata;
-  grpc_subchannel **subchannel;
+  grpc_connected_subchannel **connected_subchannel;
   grpc_closure *on_ready;
   grpc_call_element *elem;
   grpc_closure closure;
@@ -295,17 +307,17 @@ typedef struct {
 
 static int cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *arg,
                               grpc_metadata_batch *initial_metadata,
-                              grpc_subchannel **subchannel,
+                              grpc_connected_subchannel **connected_subchannel,
                               grpc_closure *on_ready);
 
 static void continue_picking(grpc_exec_ctx *exec_ctx, void *arg, int success) {
   continue_picking_args *cpa = arg;
   if (!success) {
     grpc_exec_ctx_enqueue(exec_ctx, cpa->on_ready, 0);
-  } else if (cpa->subchannel == NULL) {
+  } else if (cpa->connected_subchannel == NULL) {
     /* cancelled, do nothing */
   } else if (cc_pick_subchannel(exec_ctx, cpa->elem, cpa->initial_metadata,
-                                cpa->subchannel, cpa->on_ready)) {
+                                cpa->connected_subchannel, cpa->on_ready)) {
     grpc_exec_ctx_enqueue(exec_ctx, cpa->on_ready, 1);
   }
   gpr_free(cpa);
@@ -313,7 +325,7 @@ static void continue_picking(grpc_exec_ctx *exec_ctx, void *arg, int success) {
 
 static int cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *elemp,
                               grpc_metadata_batch *initial_metadata,
-                              grpc_subchannel **subchannel,
+                              grpc_connected_subchannel **connected_subchannel,
                               grpc_closure *on_ready) {
   grpc_call_element *elem = elemp;
   channel_data *chand = elem->channel_data;
@@ -321,18 +333,19 @@ static int cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *elemp,
   continue_picking_args *cpa;
   grpc_closure *closure;
 
-  GPR_ASSERT(subchannel);
+  GPR_ASSERT(connected_subchannel);
 
   gpr_mu_lock(&chand->mu_config);
   if (initial_metadata == NULL) {
     if (chand->lb_policy != NULL) {
-      grpc_lb_policy_cancel_pick(exec_ctx, chand->lb_policy, subchannel);
+      grpc_lb_policy_cancel_pick(exec_ctx, chand->lb_policy,
+                                 connected_subchannel);
     }
     for (closure = chand->waiting_for_config_closures.head; closure != NULL;
          closure = grpc_closure_next(closure)) {
       cpa = closure->cb_arg;
-      if (cpa->subchannel == subchannel) {
-        cpa->subchannel = NULL;
+      if (cpa->connected_subchannel == connected_subchannel) {
+        cpa->connected_subchannel = NULL;
         grpc_exec_ctx_enqueue(exec_ctx, cpa->on_ready, 0);
       }
     }
@@ -340,21 +353,22 @@ static int cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *elemp,
     return 1;
   }
   if (chand->lb_policy != NULL) {
-    int r = grpc_lb_policy_pick(exec_ctx, chand->lb_policy, calld->pollset,
-                                initial_metadata, subchannel, on_ready);
+    int r =
+        grpc_lb_policy_pick(exec_ctx, chand->lb_policy, calld->pollset,
+                            initial_metadata, connected_subchannel, on_ready);
     gpr_mu_unlock(&chand->mu_config);
     return r;
   }
   if (chand->resolver != NULL && !chand->started_resolving) {
     chand->started_resolving = 1;
-    GRPC_CHANNEL_INTERNAL_REF(chand->master, "resolver");
+    GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
     grpc_resolver_next(exec_ctx, chand->resolver,
                        &chand->incoming_configuration,
                        &chand->on_config_changed);
   }
   cpa = gpr_malloc(sizeof(*cpa));
   cpa->initial_metadata = initial_metadata;
-  cpa->subchannel = subchannel;
+  cpa->connected_subchannel = connected_subchannel;
   cpa->on_ready = on_ready;
   cpa->elem = elem;
   grpc_closure_init(&cpa->closure, continue_picking, cpa);
@@ -366,7 +380,8 @@ static int cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *elemp,
 /* Constructor for call_data */
 static void init_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                            grpc_call_element_args *args) {
-  grpc_subchannel_call_holder_init(elem->call_data, cc_pick_subchannel, elem);
+  grpc_subchannel_call_holder_init(elem->call_data, cc_pick_subchannel, elem,
+                                   args->call_stack);
 }
 
 /* Destructor for call_data */
@@ -387,13 +402,12 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(elem->filter == &grpc_client_channel_filter);
 
   gpr_mu_init(&chand->mu_config);
-  chand->mdctx = args->metadata_context;
-  chand->master = args->master;
-  grpc_pollset_set_init(&chand->pollset_set);
   grpc_closure_init(&chand->on_config_changed, cc_on_config_changed, chand);
+  chand->owning_stack = args->channel_stack;
 
   grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE,
                                "client_channel");
+  grpc_pollset_set_init(&chand->interested_parties);
 }
 
 /* Destructor for channel_data */
@@ -406,10 +420,13 @@ static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
     GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel");
   }
   if (chand->lb_policy != NULL) {
+    grpc_pollset_set_del_pollset_set(exec_ctx,
+                                     &chand->lb_policy->interested_parties,
+                                     &chand->interested_parties);
     GRPC_LB_POLICY_UNREF(exec_ctx, chand->lb_policy, "channel");
   }
   grpc_connectivity_state_destroy(exec_ctx, &chand->state_tracker);
-  grpc_pollset_set_destroy(&chand->pollset_set);
+  grpc_pollset_set_destroy(&chand->interested_parties);
   gpr_mu_destroy(&chand->mu_config);
 }
 
@@ -438,7 +455,7 @@ void grpc_client_channel_set_resolver(grpc_exec_ctx *exec_ctx,
   if (!grpc_closure_list_empty(chand->waiting_for_config_closures) ||
       chand->exit_idle_when_lb_policy_arrives) {
     chand->started_resolving = 1;
-    GRPC_CHANNEL_INTERNAL_REF(chand->master, "resolver");
+    GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
     grpc_resolver_next(exec_ctx, resolver, &chand->incoming_configuration,
                        &chand->on_config_changed);
   }
@@ -457,7 +474,7 @@ grpc_connectivity_state grpc_client_channel_check_connectivity_state(
     } else {
       chand->exit_idle_when_lb_policy_arrives = 1;
       if (!chand->started_resolving && chand->resolver != NULL) {
-        GRPC_CHANNEL_INTERNAL_REF(chand->master, "resolver");
+        GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
         chand->started_resolving = 1;
         grpc_resolver_next(exec_ctx, chand->resolver,
                            &chand->incoming_configuration,
@@ -469,32 +486,39 @@ grpc_connectivity_state grpc_client_channel_check_connectivity_state(
   return out;
 }
 
+typedef struct {
+  channel_data *chand;
+  grpc_pollset *pollset;
+  grpc_closure *on_complete;
+  grpc_closure my_closure;
+} external_connectivity_watcher;
+
+static void on_external_watch_complete(grpc_exec_ctx *exec_ctx, void *arg,
+                                       int iomgr_success) {
+  external_connectivity_watcher *w = arg;
+  grpc_closure *follow_up = w->on_complete;
+  grpc_pollset_set_del_pollset(exec_ctx, &w->chand->interested_parties,
+                               w->pollset);
+  GRPC_CHANNEL_STACK_UNREF(exec_ctx, w->chand->owning_stack,
+                           "external_connectivity_watcher");
+  gpr_free(w);
+  follow_up->cb(exec_ctx, follow_up->cb_arg, iomgr_success);
+}
+
 void grpc_client_channel_watch_connectivity_state(
-    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
+    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
     grpc_connectivity_state *state, grpc_closure *on_complete) {
   channel_data *chand = elem->channel_data;
+  external_connectivity_watcher *w = gpr_malloc(sizeof(*w));
+  w->chand = chand;
+  w->pollset = pollset;
+  w->on_complete = on_complete;
+  grpc_pollset_set_add_pollset(exec_ctx, &chand->interested_parties, pollset);
+  grpc_closure_init(&w->my_closure, on_external_watch_complete, w);
+  GRPC_CHANNEL_STACK_REF(w->chand->owning_stack,
+                         "external_connectivity_watcher");
   gpr_mu_lock(&chand->mu_config);
   grpc_connectivity_state_notify_on_state_change(
-      exec_ctx, &chand->state_tracker, state, on_complete);
+      exec_ctx, &chand->state_tracker, state, &w->my_closure);
   gpr_mu_unlock(&chand->mu_config);
 }
-
-grpc_pollset_set *grpc_client_channel_get_connecting_pollset_set(
-    grpc_channel_element *elem) {
-  channel_data *chand = elem->channel_data;
-  return &chand->pollset_set;
-}
-
-void grpc_client_channel_add_interested_party(grpc_exec_ctx *exec_ctx,
-                                              grpc_channel_element *elem,
-                                              grpc_pollset *pollset) {
-  channel_data *chand = elem->channel_data;
-  grpc_pollset_set_add_pollset(exec_ctx, &chand->pollset_set, pollset);
-}
-
-void grpc_client_channel_del_interested_party(grpc_exec_ctx *exec_ctx,
-                                              grpc_channel_element *elem,
-                                              grpc_pollset *pollset) {
-  channel_data *chand = elem->channel_data;
-  grpc_pollset_set_del_pollset(exec_ctx, &chand->pollset_set, pollset);
-}

src/core/channel/client_channel.h

@@ -57,17 +57,7 @@ grpc_connectivity_state grpc_client_channel_check_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, int try_to_connect);
 
 void grpc_client_channel_watch_connectivity_state(
-    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
+    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
     grpc_connectivity_state *state, grpc_closure *on_complete);
 
-grpc_pollset_set *grpc_client_channel_get_connecting_pollset_set(
-    grpc_channel_element *elem);
-
-void grpc_client_channel_add_interested_party(grpc_exec_ctx *exec_ctx,
-                                              grpc_channel_element *channel,
-                                              grpc_pollset *pollset);
-void grpc_client_channel_del_interested_party(grpc_exec_ctx *exec_ctx,
-                                              grpc_channel_element *channel,
-                                              grpc_pollset *pollset);
-
 #endif /* GRPC_INTERNAL_CORE_CHANNEL_CLIENT_CHANNEL_H */

src/core/channel/client_uchannel.c

@@ -54,20 +54,17 @@
  * load-balancing mechanisms meant for communication from within the core. */
 
 typedef struct client_uchannel_channel_data {
-  /** metadata context for this channel */
-  grpc_mdctx *mdctx;
-
   /** master channel - the grpc_channel instance that ultimately owns
       this channel_data via its channel stack.
       We occasionally use this to bump the refcount on the master channel
       to keep ourselves alive through an asynchronous operation. */
-  grpc_channel *master;
+  grpc_channel_stack *owning_stack;
 
   /** connectivity state being tracked */
   grpc_connectivity_state_tracker state_tracker;
 
   /** the subchannel wrapped by the microchannel */
-  grpc_subchannel *subchannel;
+  grpc_connected_subchannel *connected_subchannel;
 
   /** the callback used to stay subscribed to subchannel connectivity
    * notifications */
@@ -87,15 +84,13 @@ static void monitor_subchannel(grpc_exec_ctx *exec_ctx, void *arg,
   grpc_connectivity_state_set(exec_ctx, &chand->state_tracker,
                               chand->subchannel_connectivity,
                               "uchannel_monitor_subchannel");
-  grpc_subchannel_notify_on_state_change(exec_ctx, chand->subchannel,
-                                         &chand->subchannel_connectivity,
-                                         &chand->connectivity_cb);
+  grpc_connected_subchannel_notify_on_state_change(
+      exec_ctx, chand->connected_subchannel, NULL,
+      &chand->subchannel_connectivity, &chand->connectivity_cb);
 }
 
 static char *cuc_get_peer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
-  channel_data *chand = elem->channel_data;
-  return grpc_subchannel_call_holder_get_peer(exec_ctx, elem->call_data,
-                                              chand->master);
+  return grpc_subchannel_call_holder_get_peer(exec_ctx, elem->call_data);
 }
 
 static void cuc_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
@@ -131,11 +126,11 @@ static void cuc_start_transport_op(grpc_exec_ctx *exec_ctx,
 
 static int cuc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *arg,
                                grpc_metadata_batch *initial_metadata,
-                               grpc_subchannel **subchannel,
+                               grpc_connected_subchannel **connected_subchannel,
                                grpc_closure *on_ready) {
   channel_data *chand = arg;
   GPR_ASSERT(initial_metadata != NULL);
-  *subchannel = chand->subchannel;
+  *connected_subchannel = chand->connected_subchannel;
   return 1;
 }
 
@@ -143,7 +138,7 @@ static int cuc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *arg,
 static void cuc_init_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                                grpc_call_element_args *args) {
   grpc_subchannel_call_holder_init(elem->call_data, cuc_pick_subchannel,
-                                   elem->channel_data);
+                                   elem->channel_data, args->call_stack);
 }
 
 /* Destructor for call_data */
@@ -161,8 +156,7 @@ static void cuc_init_channel_elem(grpc_exec_ctx *exec_ctx,
   grpc_closure_init(&chand->connectivity_cb, monitor_subchannel, chand);
   GPR_ASSERT(args->is_last);
   GPR_ASSERT(elem->filter == &grpc_client_uchannel_filter);
-  chand->mdctx = args->metadata_context;
-  chand->master = args->master;
+  chand->owning_stack = args->channel_stack;
   grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE,
                                "client_uchannel");
   gpr_mu_init(&chand->mu_state);
@@ -172,10 +166,14 @@ static void cuc_init_channel_elem(grpc_exec_ctx *exec_ctx,
 static void cuc_destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                      grpc_channel_element *elem) {
   channel_data *chand = elem->channel_data;
-  grpc_subchannel_state_change_unsubscribe(exec_ctx, chand->subchannel,
-                                           &chand->connectivity_cb);
+  /* cancel subscription */
+  grpc_connected_subchannel_notify_on_state_change(
+      exec_ctx, chand->connected_subchannel, NULL, NULL,
+      &chand->connectivity_cb);
   grpc_connectivity_state_destroy(exec_ctx, &chand->state_tracker);
   gpr_mu_destroy(&chand->mu_state);
+  GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, chand->connected_subchannel,
+                                  "uchannel");
 }
 
 static void cuc_set_pollset(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
@@ -195,23 +193,14 @@ grpc_connectivity_state grpc_client_uchannel_check_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, int try_to_connect) {
   channel_data *chand = elem->channel_data;
   grpc_connectivity_state out;
-  out = grpc_connectivity_state_check(&chand->state_tracker);
   gpr_mu_lock(&chand->mu_state);
-  if (out == GRPC_CHANNEL_IDLE && try_to_connect) {
-    grpc_connectivity_state_set(exec_ctx, &chand->state_tracker,
-                                GRPC_CHANNEL_CONNECTING,
-                                "uchannel_connecting_changed");
-    chand->subchannel_connectivity = out;
-    grpc_subchannel_notify_on_state_change(exec_ctx, chand->subchannel,
-                                           &chand->subchannel_connectivity,
-                                           &chand->connectivity_cb);
-  }
+  out = grpc_connectivity_state_check(&chand->state_tracker);
   gpr_mu_unlock(&chand->mu_state);
   return out;
 }
 
 void grpc_client_uchannel_watch_connectivity_state(
-    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
+    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
     grpc_connectivity_state *state, grpc_closure *on_complete) {
   channel_data *chand = elem->channel_data;
   gpr_mu_lock(&chand->mu_state);
@@ -220,45 +209,14 @@ void grpc_client_uchannel_watch_connectivity_state(
   gpr_mu_unlock(&chand->mu_state);
 }
 
-grpc_pollset_set *grpc_client_uchannel_get_connecting_pollset_set(
-    grpc_channel_element *elem) {
-  channel_data *chand = elem->channel_data;
-  grpc_channel_element *parent_elem;
-  gpr_mu_lock(&chand->mu_state);
-  parent_elem = grpc_channel_stack_last_element(grpc_channel_get_channel_stack(
-      grpc_subchannel_get_master(chand->subchannel)));
-  gpr_mu_unlock(&chand->mu_state);
-  return grpc_client_channel_get_connecting_pollset_set(parent_elem);
-}
-
-void grpc_client_uchannel_add_interested_party(grpc_exec_ctx *exec_ctx,
-                                               grpc_channel_element *elem,
-                                               grpc_pollset *pollset) {
-  grpc_pollset_set *master_pollset_set =
-      grpc_client_uchannel_get_connecting_pollset_set(elem);
-  grpc_pollset_set_add_pollset(exec_ctx, master_pollset_set, pollset);
-}
-
-void grpc_client_uchannel_del_interested_party(grpc_exec_ctx *exec_ctx,
-                                               grpc_channel_element *elem,
-                                               grpc_pollset *pollset) {
-  grpc_pollset_set *master_pollset_set =
-      grpc_client_uchannel_get_connecting_pollset_set(elem);
-  grpc_pollset_set_del_pollset(exec_ctx, master_pollset_set, pollset);
-}
-
 grpc_channel *grpc_client_uchannel_create(grpc_subchannel *subchannel,
                                           grpc_channel_args *args) {
   grpc_channel *channel = NULL;
 #define MAX_FILTERS 3
   const grpc_channel_filter *filters[MAX_FILTERS];
-  grpc_mdctx *mdctx = grpc_subchannel_get_mdctx(subchannel);
-  grpc_channel *master = grpc_subchannel_get_master(subchannel);
-  char *target = grpc_channel_get_target(master);
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   size_t n = 0;
 
-  grpc_mdctx_ref(mdctx);
   if (grpc_channel_args_is_census_enabled(args)) {
     filters[n++] = &grpc_client_census_filter;
   }
@@ -266,20 +224,20 @@ grpc_channel *grpc_client_uchannel_create(grpc_subchannel *subchannel,
   filters[n++] = &grpc_client_uchannel_filter;
   GPR_ASSERT(n <= MAX_FILTERS);
 
-  channel = grpc_channel_create_from_filters(&exec_ctx, target, filters, n,
-                                             args, mdctx, 1);
+  channel =
+      grpc_channel_create_from_filters(&exec_ctx, NULL, filters, n, args, 1);
 
-  gpr_free(target);
   return channel;
 }
 
-void grpc_client_uchannel_set_subchannel(grpc_channel *uchannel,
-                                         grpc_subchannel *subchannel) {
+void grpc_client_uchannel_set_connected_subchannel(
+    grpc_channel *uchannel, grpc_connected_subchannel *connected_subchannel) {
   grpc_channel_element *elem =
       grpc_channel_stack_last_element(grpc_channel_get_channel_stack(uchannel));
   channel_data *chand = elem->channel_data;
   GPR_ASSERT(elem->filter == &grpc_client_uchannel_filter);
   gpr_mu_lock(&chand->mu_state);
-  chand->subchannel = subchannel;
+  chand->connected_subchannel = connected_subchannel;
+  GRPC_CONNECTED_SUBCHANNEL_REF(connected_subchannel, "uchannel");
   gpr_mu_unlock(&chand->mu_state);
 }

src/core/channel/client_uchannel.h

@@ -48,23 +48,13 @@ grpc_connectivity_state grpc_client_uchannel_check_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, int try_to_connect);
 
 void grpc_client_uchannel_watch_connectivity_state(
-    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
+    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
     grpc_connectivity_state *state, grpc_closure *on_complete);
 
-grpc_pollset_set *grpc_client_uchannel_get_connecting_pollset_set(
-    grpc_channel_element *elem);
-
-void grpc_client_uchannel_add_interested_party(grpc_exec_ctx *exec_ctx,
-                                               grpc_channel_element *channel,
-                                               grpc_pollset *pollset);
-void grpc_client_uchannel_del_interested_party(grpc_exec_ctx *exec_ctx,
-                                               grpc_channel_element *channel,
-                                               grpc_pollset *pollset);
-
 grpc_channel *grpc_client_uchannel_create(grpc_subchannel *subchannel,
                                           grpc_channel_args *args);
 
-void grpc_client_uchannel_set_subchannel(grpc_channel *uchannel,
-                                         grpc_subchannel *subchannel);
+void grpc_client_uchannel_set_connected_subchannel(
+    grpc_channel *uchannel, grpc_connected_subchannel *connected_subchannel);
 
 #endif /* GRPC_INTERNAL_CORE_CHANNEL_CLIENT_MICROCHANNEL_H */

src/core/channel/compress_filter.c

@@ -39,11 +39,13 @@
 #include <grpc/support/log.h>
 #include <grpc/support/slice_buffer.h>
 
-#include "src/core/channel/compress_filter.h"
 #include "src/core/channel/channel_args.h"
-#include "src/core/profiling/timers.h"
+#include "src/core/channel/compress_filter.h"
+#include "src/core/compression/algorithm_metadata.h"
 #include "src/core/compression/message_compress.h"
+#include "src/core/profiling/timers.h"
 #include "src/core/support/string.h"
+#include "src/core/transport/static_metadata.h"
 
 typedef struct call_data {
   gpr_slice_buffer slices; /**< Buffers up input slices to be compressed */
@@ -67,20 +69,12 @@ typedef struct call_data {
 } call_data;
 
 typedef struct channel_data {
-  /** Metadata key for the incoming (requested) compression algorithm */
-  grpc_mdstr *mdstr_request_compression_algorithm_key;
-  /** Metadata key for the outgoing (used) compression algorithm */
-  grpc_mdstr *mdstr_outgoing_compression_algorithm_key;
-  /** Metadata key for the accepted encodings */
-  grpc_mdstr *mdstr_compression_capabilities_key;
-  /** Precomputed metadata elements for all available compression algorithms */
-  grpc_mdelem *mdelem_compression_algorithms[GRPC_COMPRESS_ALGORITHMS_COUNT];
-  /** Precomputed metadata elements for the accepted encodings */
-  grpc_mdelem *mdelem_accept_encoding;
   /** The default, channel-level, compression algorithm */
   grpc_compression_algorithm default_compression_algorithm;
   /** Compression options for the channel */
   grpc_compression_options compression_options;
+  /** Supported compression algorithms */
+  gpr_uint32 supported_compression_algorithms;
 } channel_data;
 
 /** For each \a md element from the incoming metadata, filter out the entry for
@@ -91,7 +85,7 @@ static grpc_mdelem *compression_md_filter(void *user_data, grpc_mdelem *md) {
   call_data *calld = elem->call_data;
   channel_data *channeld = elem->channel_data;
 
-  if (md->key == channeld->mdstr_request_compression_algorithm_key) {
+  if (md->key == GRPC_MDSTR_GRPC_INTERNAL_ENCODING_REQUEST) {
     const char *md_c_str = grpc_mdstr_as_c_string(md->value);
     if (!grpc_compression_algorithm_parse(md_c_str, strlen(md_c_str),
                                           &calld->compression_algorithm)) {
@@ -147,14 +141,13 @@ static void process_send_initial_metadata(
   /* hint compression algorithm */
   grpc_metadata_batch_add_tail(
       initial_metadata, &calld->compression_algorithm_storage,
-      GRPC_MDELEM_REF(
-          channeld
-              ->mdelem_compression_algorithms[calld->compression_algorithm]));
+      grpc_compression_encoding_mdelem(calld->compression_algorithm));
 
   /* convey supported compression algorithms */
-  grpc_metadata_batch_add_tail(
-      initial_metadata, &calld->accept_encoding_storage,
-      GRPC_MDELEM_REF(channeld->mdelem_accept_encoding));
+  grpc_metadata_batch_add_tail(initial_metadata,
+                               &calld->accept_encoding_storage,
+                               GRPC_MDELEM_ACCEPT_ENCODING_FOR_ALGORITHMS(
+                                   channeld->supported_compression_algorithms));
 }
 
 static void continue_send_message(grpc_exec_ctx *exec_ctx,
@@ -266,10 +259,6 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
                               grpc_channel_element_args *args) {
   channel_data *channeld = elem->channel_data;
   grpc_compression_algorithm algo_idx;
-  const char *supported_algorithms_names[GRPC_COMPRESS_ALGORITHMS_COUNT - 1];
-  size_t supported_algorithms_idx = 0;
-  char *accept_encoding_str;
-  size_t accept_encoding_str_len;
 
   grpc_compression_options_init(&channeld->compression_options);
   channeld->compression_options.enabled_algorithms_bitset =
@@ -284,62 +273,22 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
   channeld->compression_options.default_compression_algorithm =
       channeld->default_compression_algorithm;
 
-  channeld->mdstr_request_compression_algorithm_key = grpc_mdstr_from_string(
-      args->metadata_context, GRPC_COMPRESS_REQUEST_ALGORITHM_KEY);
-
-  channeld->mdstr_outgoing_compression_algorithm_key =
-      grpc_mdstr_from_string(args->metadata_context, "grpc-encoding");
-
-  channeld->mdstr_compression_capabilities_key =
-      grpc_mdstr_from_string(args->metadata_context, "grpc-accept-encoding");
-
+  channeld->supported_compression_algorithms = 0;
   for (algo_idx = 0; algo_idx < GRPC_COMPRESS_ALGORITHMS_COUNT; ++algo_idx) {
-    char *algorithm_name;
     /* skip disabled algorithms */
     if (grpc_compression_options_is_algorithm_enabled(
             &channeld->compression_options, algo_idx) == 0) {
       continue;
     }
-    GPR_ASSERT(grpc_compression_algorithm_name(algo_idx, &algorithm_name) != 0);
-    channeld->mdelem_compression_algorithms[algo_idx] =
-        grpc_mdelem_from_metadata_strings(
-            args->metadata_context,
-            GRPC_MDSTR_REF(channeld->mdstr_outgoing_compression_algorithm_key),
-            grpc_mdstr_from_string(args->metadata_context, algorithm_name));
-    if (algo_idx > 0) {
-      supported_algorithms_names[supported_algorithms_idx++] = algorithm_name;
-    }
+    channeld->supported_compression_algorithms |= 1u << algo_idx;
   }
 
-  /* TODO(dgq): gpr_strjoin_sep could be made to work with statically allocated
-   * arrays, as to avoid the heap allocs */
-  accept_encoding_str =
-      gpr_strjoin_sep(supported_algorithms_names, supported_algorithms_idx, ",",
-                      &accept_encoding_str_len);
-
-  channeld->mdelem_accept_encoding = grpc_mdelem_from_metadata_strings(
-      args->metadata_context,
-      GRPC_MDSTR_REF(channeld->mdstr_compression_capabilities_key),
-      grpc_mdstr_from_string(args->metadata_context, accept_encoding_str));
-  gpr_free(accept_encoding_str);
-
   GPR_ASSERT(!args->is_last);
 }
 
 /* Destructor for channel data */
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
-                                 grpc_channel_element *elem) {
-  channel_data *channeld = elem->channel_data;
-  grpc_compression_algorithm algo_idx;
-
-  GRPC_MDSTR_UNREF(channeld->mdstr_request_compression_algorithm_key);
-  GRPC_MDSTR_UNREF(channeld->mdstr_outgoing_compression_algorithm_key);
-  GRPC_MDSTR_UNREF(channeld->mdstr_compression_capabilities_key);
-  for (algo_idx = 0; algo_idx < GRPC_COMPRESS_ALGORITHMS_COUNT; ++algo_idx) {
-    GRPC_MDELEM_UNREF(channeld->mdelem_compression_algorithms[algo_idx]);
-  }
-  GRPC_MDELEM_UNREF(channeld->mdelem_accept_encoding);
-}
+                                 grpc_channel_element *elem) {}
 
 const grpc_channel_filter grpc_compress_filter = {
     compress_start_transport_stream_op, grpc_channel_next_op, sizeof(call_data),

src/core/channel/connected_channel.c

@@ -89,9 +89,9 @@ static void init_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   int r;
 
   GPR_ASSERT(elem->filter == &grpc_connected_channel_filter);
-  r = grpc_transport_init_stream(exec_ctx, chand->transport,
-                                 TRANSPORT_STREAM_FROM_CALL_DATA(calld),
-                                 args->refcount, args->server_transport_data);
+  r = grpc_transport_init_stream(
+      exec_ctx, chand->transport, TRANSPORT_STREAM_FROM_CALL_DATA(calld),
+      &args->call_stack->refcount, args->server_transport_data);
   GPR_ASSERT(r == 0);
 }
 

src/core/channel/http_client_filter.c

@@ -31,12 +31,13 @@
  */
 
 #include "src/core/channel/http_client_filter.h"
-#include <string.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
-#include "src/core/support/string.h"
+#include <string.h>
 #include "src/core/profiling/timers.h"
+#include "src/core/support/string.h"
+#include "src/core/transport/static_metadata.h"
 
 typedef struct call_data {
   grpc_linked_mdelem method;
@@ -57,12 +58,7 @@ typedef struct call_data {
 } call_data;
 
 typedef struct channel_data {
-  grpc_mdelem *te_trailers;
-  grpc_mdelem *method;
-  grpc_mdelem *scheme;
-  grpc_mdelem *content_type;
-  grpc_mdelem *status;
-  /** complete user agent mdelem */
+  grpc_mdelem *static_scheme;
   grpc_mdelem *user_agent;
 } channel_data;
 
@@ -73,14 +69,12 @@ typedef struct {
 
 static grpc_mdelem *client_recv_filter(void *user_data, grpc_mdelem *md) {
   client_recv_filter_args *a = user_data;
-  grpc_call_element *elem = a->elem;
-  channel_data *channeld = elem->channel_data;
-  if (md == channeld->status) {
+  if (md == GRPC_MDELEM_STATUS_200) {
     return NULL;
-  } else if (md->key == channeld->status->key) {
-    grpc_call_element_send_cancel(a->exec_ctx, elem);
+  } else if (md->key == GRPC_MDSTR_STATUS) {
+    grpc_call_element_send_cancel(a->exec_ctx, a->elem);
     return NULL;
-  } else if (md->key == channeld->content_type->key) {
+  } else if (md->key == GRPC_MDSTR_CONTENT_TYPE) {
     return NULL;
   }
   return md;
@@ -98,14 +92,12 @@ static void hc_on_recv(grpc_exec_ctx *exec_ctx, void *user_data, int success) {
 }
 
 static grpc_mdelem *client_strip_filter(void *user_data, grpc_mdelem *md) {
-  grpc_call_element *elem = user_data;
-  channel_data *channeld = elem->channel_data;
   /* eat the things we'd like to set ourselves */
-  if (md->key == channeld->method->key) return NULL;
-  if (md->key == channeld->scheme->key) return NULL;
-  if (md->key == channeld->te_trailers->key) return NULL;
-  if (md->key == channeld->content_type->key) return NULL;
-  if (md->key == channeld->user_agent->key) return NULL;
+  if (md->key == GRPC_MDSTR_METHOD) return NULL;
+  if (md->key == GRPC_MDSTR_SCHEME) return NULL;
+  if (md->key == GRPC_MDSTR_TE) return NULL;
+  if (md->key == GRPC_MDSTR_CONTENT_TYPE) return NULL;
+  if (md->key == GRPC_MDSTR_USER_AGENT) return NULL;
   return md;
 }
 
@@ -120,14 +112,14 @@ static void hc_mutate_op(grpc_call_element *elem,
     /* Send : prefixed headers, which have to be before any application
        layer headers. */
     grpc_metadata_batch_add_head(op->send_initial_metadata, &calld->method,
-                                 GRPC_MDELEM_REF(channeld->method));
+                                 GRPC_MDELEM_METHOD_POST);
     grpc_metadata_batch_add_head(op->send_initial_metadata, &calld->scheme,
-                                 GRPC_MDELEM_REF(channeld->scheme));
+                                 channeld->static_scheme);
     grpc_metadata_batch_add_tail(op->send_initial_metadata, &calld->te_trailers,
-                                 GRPC_MDELEM_REF(channeld->te_trailers));
-    grpc_metadata_batch_add_tail(op->send_initial_metadata,
-                                 &calld->content_type,
-                                 GRPC_MDELEM_REF(channeld->content_type));
+                                 GRPC_MDELEM_TE_TRAILERS);
+    grpc_metadata_batch_add_tail(
+        op->send_initial_metadata, &calld->content_type,
+        GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC);
     grpc_metadata_batch_add_tail(op->send_initial_metadata, &calld->user_agent,
                                  GRPC_MDELEM_REF(channeld->user_agent));
   }
@@ -162,21 +154,28 @@ static void init_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
 static void destroy_call_elem(grpc_exec_ctx *exec_ctx,
                               grpc_call_element *elem) {}
 
-static const char *scheme_from_args(const grpc_channel_args *args) {
+static grpc_mdelem *scheme_from_args(const grpc_channel_args *args) {
   unsigned i;
+  size_t j;
+  grpc_mdelem *valid_schemes[] = {GRPC_MDELEM_SCHEME_HTTP,
+                                  GRPC_MDELEM_SCHEME_HTTPS};
   if (args != NULL) {
     for (i = 0; i < args->num_args; ++i) {
       if (args->args[i].type == GRPC_ARG_STRING &&
           strcmp(args->args[i].key, GRPC_ARG_HTTP2_SCHEME) == 0) {
-        return args->args[i].value.string;
+        for (j = 0; j < GPR_ARRAY_SIZE(valid_schemes); j++) {
+          if (0 == strcmp(grpc_mdstr_as_c_string(valid_schemes[j]->value),
+                          args->args[i].value.string)) {
+            return valid_schemes[j];
+          }
+        }
       }
     }
   }
-  return "http";
+  return GRPC_MDELEM_SCHEME_HTTP;
 }
 
-static grpc_mdstr *user_agent_from_args(grpc_mdctx *mdctx,
-                                        const grpc_channel_args *args) {
+static grpc_mdstr *user_agent_from_args(const grpc_channel_args *args) {
   gpr_strvec v;
   size_t i;
   int is_first = 1;
@@ -218,7 +217,7 @@ static grpc_mdstr *user_agent_from_args(grpc_mdctx *mdctx,
 
   tmp = gpr_strvec_flatten(&v, NULL);
   gpr_strvec_destroy(&v);
-  result = grpc_mdstr_from_string(mdctx, tmp);
+  result = grpc_mdstr_from_string(tmp);
   gpr_free(tmp);
 
   return result;
@@ -228,43 +227,18 @@ static grpc_mdstr *user_agent_from_args(grpc_mdctx *mdctx,
 static void init_channel_elem(grpc_exec_ctx *exec_ctx,
                               grpc_channel_element *elem,
                               grpc_channel_element_args *args) {
-  /* grab pointers to our data from the channel element */
-  channel_data *channeld = elem->channel_data;
-
-  /* The first and the last filters tend to be implemented differently to
-     handle the case that there's no 'next' filter to call on the up or down
-     path */
+  channel_data *chand = elem->channel_data;
   GPR_ASSERT(!args->is_last);
-
-  /* initialize members */
-  channeld->te_trailers =
-      grpc_mdelem_from_strings(args->metadata_context, "te", "trailers");
-  channeld->method =
-      grpc_mdelem_from_strings(args->metadata_context, ":method", "POST");
-  channeld->scheme = grpc_mdelem_from_strings(
-      args->metadata_context, ":scheme", scheme_from_args(args->channel_args));
-  channeld->content_type = grpc_mdelem_from_strings(
-      args->metadata_context, "content-type", "application/grpc");
-  channeld->status =
-      grpc_mdelem_from_strings(args->metadata_context, ":status", "200");
-  channeld->user_agent = grpc_mdelem_from_metadata_strings(
-      args->metadata_context,
-      grpc_mdstr_from_string(args->metadata_context, "user-agent"),
-      user_agent_from_args(args->metadata_context, args->channel_args));
+  chand->static_scheme = scheme_from_args(args->channel_args);
+  chand->user_agent = grpc_mdelem_from_metadata_strings(
+      GRPC_MDSTR_USER_AGENT, user_agent_from_args(args->channel_args));
 }
 
 /* Destructor for channel data */
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                  grpc_channel_element *elem) {
-  /* grab pointers to our data from the channel element */
-  channel_data *channeld = elem->channel_data;
-
-  GRPC_MDELEM_UNREF(channeld->te_trailers);
-  GRPC_MDELEM_UNREF(channeld->method);
-  GRPC_MDELEM_UNREF(channeld->scheme);
-  GRPC_MDELEM_UNREF(channeld->content_type);
-  GRPC_MDELEM_UNREF(channeld->status);
-  GRPC_MDELEM_UNREF(channeld->user_agent);
+  channel_data *chand = elem->channel_data;
+  GRPC_MDELEM_UNREF(chand->user_agent);
 }
 
 const grpc_channel_filter grpc_http_client_filter = {

src/core/channel/http_server_filter.c

@@ -33,10 +33,11 @@
 
 #include "src/core/channel/http_server_filter.h"
 
-#include <string.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <string.h>
 #include "src/core/profiling/timers.h"
+#include "src/core/transport/static_metadata.h"
 
 typedef struct call_data {
   gpr_uint8 seen_path;
@@ -57,22 +58,7 @@ typedef struct call_data {
   grpc_closure hs_on_recv;
 } call_data;
 
-typedef struct channel_data {
-  grpc_mdelem *te_trailers;
-  grpc_mdelem *method_post;
-  grpc_mdelem *http_scheme;
-  grpc_mdelem *https_scheme;
-  /* TODO(klempner): Remove this once we stop using it */
-  grpc_mdelem *grpc_scheme;
-  grpc_mdelem *content_type;
-  grpc_mdelem *status_ok;
-  grpc_mdelem *status_not_found;
-  grpc_mdstr *path_key;
-  grpc_mdstr *authority_key;
-  grpc_mdstr *host_key;
-
-  grpc_mdctx *mdctx;
-} channel_data;
+typedef struct channel_data { gpr_uint8 unused; } channel_data;
 
 typedef struct {
   grpc_call_element *elem;
@@ -82,25 +68,24 @@ typedef struct {
 static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
   server_filter_args *a = user_data;
   grpc_call_element *elem = a->elem;
-  channel_data *channeld = elem->channel_data;
   call_data *calld = elem->call_data;
 
   /* Check if it is one of the headers we care about. */
-  if (md == channeld->te_trailers || md == channeld->method_post ||
-      md == channeld->http_scheme || md == channeld->https_scheme ||
-      md == channeld->grpc_scheme || md == channeld->content_type) {
+  if (md == GRPC_MDELEM_TE_TRAILERS || md == GRPC_MDELEM_METHOD_POST ||
+      md == GRPC_MDELEM_SCHEME_HTTP || md == GRPC_MDELEM_SCHEME_HTTPS ||
+      md == GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC) {
     /* swallow it */
-    if (md == channeld->method_post) {
+    if (md == GRPC_MDELEM_METHOD_POST) {
       calld->seen_post = 1;
-    } else if (md->key == channeld->http_scheme->key) {
+    } else if (md->key == GRPC_MDSTR_SCHEME) {
       calld->seen_scheme = 1;
-    } else if (md == channeld->te_trailers) {
+    } else if (md == GRPC_MDELEM_TE_TRAILERS) {
       calld->seen_te_trailers = 1;
     }
     /* TODO(klempner): Track that we've seen all the headers we should
        require */
     return NULL;
-  } else if (md->key == channeld->content_type->key) {
+  } else if (md->key == GRPC_MDSTR_CONTENT_TYPE) {
     if (strncmp(grpc_mdstr_as_c_string(md->value), "application/grpc+", 17) ==
         0) {
       /* Although the C implementation doesn't (currently) generate them,
@@ -112,12 +97,11 @@ static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
       /* TODO(klempner): We're currently allowing this, but we shouldn't
          see it without a proxy so log for now. */
       gpr_log(GPR_INFO, "Unexpected content-type %s",
-              channeld->content_type->key);
+              grpc_mdstr_as_c_string(md->value));
     }
     return NULL;
-  } else if (md->key == channeld->te_trailers->key ||
-             md->key == channeld->method_post->key ||
-             md->key == channeld->http_scheme->key) {
+  } else if (md->key == GRPC_MDSTR_TE || md->key == GRPC_MDSTR_METHOD ||
+             md->key == GRPC_MDSTR_SCHEME) {
     gpr_log(GPR_ERROR, "Invalid %s: header: '%s'",
             grpc_mdstr_as_c_string(md->key), grpc_mdstr_as_c_string(md->value));
     /* swallow it and error everything out. */
@@ -125,23 +109,21 @@ static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
        on the wire here. */
     grpc_call_element_send_cancel(a->exec_ctx, elem);
     return NULL;
-  } else if (md->key == channeld->path_key) {
+  } else if (md->key == GRPC_MDSTR_PATH) {
     if (calld->seen_path) {
       gpr_log(GPR_ERROR, "Received :path twice");
       return NULL;
     }
     calld->seen_path = 1;
     return md;
-  } else if (md->key == channeld->authority_key) {
+  } else if (md->key == GRPC_MDSTR_AUTHORITY) {
     calld->seen_authority = 1;
     return md;
-  } else if (md->key == channeld->host_key) {
+  } else if (md->key == GRPC_MDSTR_HOST) {
     /* translate host to :authority since :authority may be
        omitted */
     grpc_mdelem *authority = grpc_mdelem_from_metadata_strings(
-        channeld->mdctx, GRPC_MDSTR_REF(channeld->authority_key),
-        GRPC_MDSTR_REF(md->value));
-    GRPC_MDELEM_UNREF(md);
+        GRPC_MDSTR_AUTHORITY, GRPC_MDSTR_REF(md->value));
     calld->seen_authority = 1;
     return authority;
   } else {
@@ -191,15 +173,14 @@ static void hs_mutate_op(grpc_call_element *elem,
                          grpc_transport_stream_op *op) {
   /* grab pointers to our data from the call element */
   call_data *calld = elem->call_data;
-  channel_data *channeld = elem->channel_data;
 
   if (op->send_initial_metadata != NULL && !calld->sent_status) {
     calld->sent_status = 1;
     grpc_metadata_batch_add_head(op->send_initial_metadata, &calld->status,
-                                 GRPC_MDELEM_REF(channeld->status_ok));
-    grpc_metadata_batch_add_tail(op->send_initial_metadata,
-                                 &calld->content_type,
-                                 GRPC_MDELEM_REF(channeld->content_type));
+                                 GRPC_MDELEM_STATUS_200);
+    grpc_metadata_batch_add_tail(
+        op->send_initial_metadata, &calld->content_type,
+        GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC);
   }
 
   if (op->recv_initial_metadata) {
@@ -238,57 +219,12 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx,
 static void init_channel_elem(grpc_exec_ctx *exec_ctx,
                               grpc_channel_element *elem,
                               grpc_channel_element_args *args) {
-  /* grab pointers to our data from the channel element */
-  channel_data *channeld = elem->channel_data;
-
-  /* The first and the last filters tend to be implemented differently to
-     handle the case that there's no 'next' filter to call on the up or down
-     path */
   GPR_ASSERT(!args->is_last);
-
-  /* initialize members */
-  channeld->te_trailers =
-      grpc_mdelem_from_strings(args->metadata_context, "te", "trailers");
-  channeld->status_ok =
-      grpc_mdelem_from_strings(args->metadata_context, ":status", "200");
-  channeld->status_not_found =
-      grpc_mdelem_from_strings(args->metadata_context, ":status", "404");
-  channeld->method_post =
-      grpc_mdelem_from_strings(args->metadata_context, ":method", "POST");
-  channeld->http_scheme =
-      grpc_mdelem_from_strings(args->metadata_context, ":scheme", "http");
-  channeld->https_scheme =
-      grpc_mdelem_from_strings(args->metadata_context, ":scheme", "https");
-  channeld->grpc_scheme =
-      grpc_mdelem_from_strings(args->metadata_context, ":scheme", "grpc");
-  channeld->path_key = grpc_mdstr_from_string(args->metadata_context, ":path");
-  channeld->authority_key =
-      grpc_mdstr_from_string(args->metadata_context, ":authority");
-  channeld->host_key = grpc_mdstr_from_string(args->metadata_context, "host");
-  channeld->content_type = grpc_mdelem_from_strings(
-      args->metadata_context, "content-type", "application/grpc");
-
-  channeld->mdctx = args->metadata_context;
 }
 
 /* Destructor for channel data */
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
-                                 grpc_channel_element *elem) {
-  /* grab pointers to our data from the channel element */
-  channel_data *channeld = elem->channel_data;
-
-  GRPC_MDELEM_UNREF(channeld->te_trailers);
-  GRPC_MDELEM_UNREF(channeld->status_ok);
-  GRPC_MDELEM_UNREF(channeld->status_not_found);
-  GRPC_MDELEM_UNREF(channeld->method_post);
-  GRPC_MDELEM_UNREF(channeld->http_scheme);
-  GRPC_MDELEM_UNREF(channeld->https_scheme);
-  GRPC_MDELEM_UNREF(channeld->grpc_scheme);
-  GRPC_MDELEM_UNREF(channeld->content_type);
-  GRPC_MDSTR_UNREF(channeld->path_key);
-  GRPC_MDSTR_UNREF(channeld->authority_key);
-  GRPC_MDSTR_UNREF(channeld->host_key);
-}
+                                 grpc_channel_element *elem) {}
 
 const grpc_channel_filter grpc_http_server_filter = {
     hs_start_transport_op, grpc_channel_next_op, sizeof(call_data),

src/core/channel/noop_filter.c

@@ -1,118 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "src/core/channel/noop_filter.h"
-#include <grpc/support/log.h>
-
-typedef struct call_data {
-  int unused; /* C89 requires at least one struct element */
-} call_data;
-
-typedef struct channel_data {
-  int unused; /* C89 requires at least one struct element */
-} channel_data;
-
-/* used to silence 'variable not used' warnings */
-static void ignore_unused(void *ignored) {}
-
-static void noop_mutate_op(grpc_call_element *elem,
-                           grpc_transport_stream_op *op) {
-  /* grab pointers to our data from the call element */
-  call_data *calld = elem->call_data;
-  channel_data *channeld = elem->channel_data;
-
-  ignore_unused(calld);
-  ignore_unused(channeld);
-
-  /* do nothing */
-}
-
-/* Called either:
-     - in response to an API call (or similar) from above, to send something
-     - a network event (or similar) from below, to receive something
-   op contains type and call direction information, in addition to the data
-   that is being sent or received. */
-static void noop_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
-                                           grpc_call_element *elem,
-                                           grpc_transport_stream_op *op) {
-  noop_mutate_op(elem, op);
-
-  /* pass control down the stack */
-  grpc_call_next_op(exec_ctx, elem, op);
-}
-
-/* Constructor for call_data */
-static void init_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
-                           grpc_call_element_args *args) {
-  /* grab pointers to our data from the call element */
-  call_data *calld = elem->call_data;
-  channel_data *channeld = elem->channel_data;
-
-  /* initialize members */
-  calld->unused = channeld->unused;
-}
-
-/* Destructor for call_data */
-static void destroy_call_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_call_element *elem) {}
-
-/* Constructor for channel_data */
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
-  /* grab pointers to our data from the channel element */
-  channel_data *channeld = elem->channel_data;
-
-  /* The last filter tends to be implemented differently to
-     handle the case that there's no 'next' filter to call on the down
-     path */
-  GPR_ASSERT(!args->is_last);
-
-  /* initialize members */
-  channeld->unused = 0;
-}
-
-/* Destructor for channel data */
-static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
-                                 grpc_channel_element *elem) {
-  /* grab pointers to our data from the channel element */
-  channel_data *channeld = elem->channel_data;
-
-  ignore_unused(channeld);
-}
-
-const grpc_channel_filter grpc_no_op_filter = {
-    noop_start_transport_stream_op, grpc_channel_next_op, sizeof(call_data),
-    init_call_elem, grpc_call_stack_ignore_set_pollset, destroy_call_elem,
-    sizeof(channel_data), init_channel_elem, destroy_channel_elem,
-    grpc_call_next_get_peer, "no-op"};

src/core/channel/subchannel_call_holder.c

@@ -44,7 +44,6 @@
 
 static void subchannel_ready(grpc_exec_ctx *exec_ctx, void *holder,
                              int success);
-static void call_ready(grpc_exec_ctx *exec_ctx, void *holder, int success);
 static void retry_ops(grpc_exec_ctx *exec_ctx, void *retry_ops_args,
                       int success);
 
@@ -58,16 +57,17 @@ static void retry_waiting_locked(grpc_exec_ctx *exec_ctx,
 void grpc_subchannel_call_holder_init(
     grpc_subchannel_call_holder *holder,
     grpc_subchannel_call_holder_pick_subchannel pick_subchannel,
-    void *pick_subchannel_arg) {
+    void *pick_subchannel_arg, grpc_call_stack *owning_call) {
   gpr_atm_rel_store(&holder->subchannel_call, 0);
   holder->pick_subchannel = pick_subchannel;
   holder->pick_subchannel_arg = pick_subchannel_arg;
   gpr_mu_init(&holder->mu);
-  holder->subchannel = NULL;
+  holder->connected_subchannel = NULL;
   holder->waiting_ops = NULL;
   holder->waiting_ops_count = 0;
   holder->waiting_ops_capacity = 0;
   holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
+  holder->owning_call = owning_call;
 }
 
 void grpc_subchannel_call_holder_destroy(grpc_exec_ctx *exec_ctx,
@@ -125,13 +125,9 @@ retry:
         case GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING:
           fail_locked(exec_ctx, holder);
           break;
-        case GRPC_SUBCHANNEL_CALL_HOLDER_CREATING_CALL:
-          grpc_subchannel_cancel_create_call(exec_ctx, holder->subchannel,
-                                             &holder->subchannel_call);
-          break;
         case GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL:
           holder->pick_subchannel(exec_ctx, holder->pick_subchannel_arg, NULL,
-                                  &holder->subchannel, NULL);
+                                  &holder->connected_subchannel, NULL);
           break;
       }
       gpr_mu_unlock(&holder->mu);
@@ -142,28 +138,27 @@ retry:
   }
   /* if we don't have a subchannel, try to get one */
   if (holder->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
-      holder->subchannel == NULL && op->send_initial_metadata != NULL) {
+      holder->connected_subchannel == NULL &&
+      op->send_initial_metadata != NULL) {
     holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL;
     grpc_closure_init(&holder->next_step, subchannel_ready, holder);
-    if (holder->pick_subchannel(exec_ctx, holder->pick_subchannel_arg,
-                                op->send_initial_metadata, &holder->subchannel,
-                                &holder->next_step)) {
+    GRPC_CALL_STACK_REF(holder->owning_call, "pick_subchannel");
+    if (holder->pick_subchannel(
+            exec_ctx, holder->pick_subchannel_arg, op->send_initial_metadata,
+            &holder->connected_subchannel, &holder->next_step)) {
       holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
+      GRPC_CALL_STACK_UNREF(exec_ctx, holder->owning_call, "pick_subchannel");
     }
   }
   /* if we've got a subchannel, then let's ask it to create a call */
   if (holder->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
-      holder->subchannel != NULL) {
-    holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_CREATING_CALL;
-    grpc_closure_init(&holder->next_step, call_ready, holder);
-    if (grpc_subchannel_create_call(exec_ctx, holder->subchannel,
-                                    holder->pollset, &holder->subchannel_call,
-                                    &holder->next_step)) {
-      /* got one immediately - continue the op (and any waiting ops) */
-      holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
-      retry_waiting_locked(exec_ctx, holder);
-      goto retry;
-    }
+      holder->connected_subchannel != NULL) {
+    gpr_atm_rel_store(
+        &holder->subchannel_call,
+        (gpr_atm)(gpr_uintptr)grpc_connected_subchannel_create_call(
+            exec_ctx, holder->connected_subchannel, holder->pollset));
+    retry_waiting_locked(exec_ctx, holder);
+    goto retry;
   }
   /* nothing to be done but wait */
   add_waiting_locked(holder, op);
@@ -179,36 +174,18 @@ static void subchannel_ready(grpc_exec_ctx *exec_ctx, void *arg, int success) {
              GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL);
   call = GET_CALL(holder);
   GPR_ASSERT(call == NULL || call == CANCELLED_CALL);
-  if (holder->subchannel == NULL) {
-    holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
+  holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
+  if (holder->connected_subchannel == NULL) {
     fail_locked(exec_ctx, holder);
   } else {
-    grpc_closure_init(&holder->next_step, call_ready, holder);
-    if (grpc_subchannel_create_call(exec_ctx, holder->subchannel,
-                                    holder->pollset, &holder->subchannel_call,
-                                    &holder->next_step)) {
-      holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
-      /* got one immediately - continue the op (and any waiting ops) */
-      retry_waiting_locked(exec_ctx, holder);
-    }
-  }
-  gpr_mu_unlock(&holder->mu);
-}
-
-static void call_ready(grpc_exec_ctx *exec_ctx, void *arg, int success) {
-  grpc_subchannel_call_holder *holder = arg;
-  GPR_TIMER_BEGIN("call_ready", 0);
-  gpr_mu_lock(&holder->mu);
-  GPR_ASSERT(holder->creation_phase ==
-             GRPC_SUBCHANNEL_CALL_HOLDER_CREATING_CALL);
-  holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
-  if (GET_CALL(holder) != NULL) {
+    gpr_atm_rel_store(
+        &holder->subchannel_call,
+        (gpr_atm)(gpr_uintptr)grpc_connected_subchannel_create_call(
+            exec_ctx, holder->connected_subchannel, holder->pollset));
     retry_waiting_locked(exec_ctx, holder);
-  } else {
-    fail_locked(exec_ctx, holder);
   }
   gpr_mu_unlock(&holder->mu);
-  GPR_TIMER_END("call_ready", 0);
+  GRPC_CALL_STACK_UNREF(exec_ctx, holder->owning_call, "pick_subchannel");
 }
 
 typedef struct {
@@ -270,14 +247,13 @@ static void fail_locked(grpc_exec_ctx *exec_ctx,
   holder->waiting_ops_count = 0;
 }
 
-char *grpc_subchannel_call_holder_get_peer(grpc_exec_ctx *exec_ctx,
-                                           grpc_subchannel_call_holder *holder,
-                                           grpc_channel *master) {
+char *grpc_subchannel_call_holder_get_peer(
+    grpc_exec_ctx *exec_ctx, grpc_subchannel_call_holder *holder) {
   grpc_subchannel_call *subchannel_call = GET_CALL(holder);
 
   if (subchannel_call) {
     return grpc_subchannel_call_get_peer(exec_ctx, subchannel_call);
   } else {
-    return grpc_channel_get_target(master);
+    return NULL;
   }
 }

src/core/channel/subchannel_call_holder.h

@@ -42,12 +42,11 @@
     called when the subchannel is available) */
 typedef int (*grpc_subchannel_call_holder_pick_subchannel)(
     grpc_exec_ctx *exec_ctx, void *arg, grpc_metadata_batch *initial_metadata,
-    grpc_subchannel **subchannel, grpc_closure *on_ready);
+    grpc_connected_subchannel **connected_subchannel, grpc_closure *on_ready);
 
 typedef enum {
   GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING,
-  GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL,
-  GRPC_SUBCHANNEL_CALL_HOLDER_CREATING_CALL
+  GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL
 } grpc_subchannel_call_holder_creation_phase;
 
 /** Wrapper for holding a pointer to grpc_subchannel_call, and the
@@ -71,7 +70,7 @@ typedef struct grpc_subchannel_call_holder {
   gpr_mu mu;
 
   grpc_subchannel_call_holder_creation_phase creation_phase;
-  grpc_subchannel *subchannel;
+  grpc_connected_subchannel *connected_subchannel;
   grpc_pollset *pollset;
 
   grpc_transport_stream_op *waiting_ops;
@@ -79,12 +78,14 @@ typedef struct grpc_subchannel_call_holder {
   size_t waiting_ops_capacity;
 
   grpc_closure next_step;
+
+  grpc_call_stack *owning_call;
 } grpc_subchannel_call_holder;
 
 void grpc_subchannel_call_holder_init(
     grpc_subchannel_call_holder *holder,
     grpc_subchannel_call_holder_pick_subchannel pick_subchannel,
-    void *pick_subchannel_arg);
+    void *pick_subchannel_arg, grpc_call_stack *owning_call);
 void grpc_subchannel_call_holder_destroy(grpc_exec_ctx *exec_ctx,
                                          grpc_subchannel_call_holder *holder);
 
@@ -92,7 +93,6 @@ void grpc_subchannel_call_holder_perform_op(grpc_exec_ctx *exec_ctx,
                                             grpc_subchannel_call_holder *holder,
                                             grpc_transport_stream_op *op);
 char *grpc_subchannel_call_holder_get_peer(grpc_exec_ctx *exec_ctx,
-                                           grpc_subchannel_call_holder *holder,
-                                           grpc_channel *master);
+                                           grpc_subchannel_call_holder *holder);
 
 #endif

src/core/client_config/connector.h

@@ -65,6 +65,9 @@ typedef struct {
   /** any additional filters (owned by the caller of connect) */
   const grpc_channel_filter **filters;
   size_t num_filters;
+
+  /** channel arguments (to be passed to the filters) */
+  const grpc_channel_args *channel_args;
 } grpc_connect_out_args;
 
 struct grpc_connector_vtable {

src/core/client_config/lb_policies/pick_first.c

@@ -42,7 +42,7 @@
 typedef struct pending_pick {
   struct pending_pick *next;
   grpc_pollset *pollset;
-  grpc_subchannel **target;
+  grpc_connected_subchannel **target;
   grpc_closure *on_complete;
 } pending_pick;
 
@@ -60,7 +60,7 @@ typedef struct {
   /** the selected channel
       TODO(ctiller): this should be atomically set so we don't
                      need to take a mutex in the common case */
-  grpc_subchannel *selected;
+  grpc_connected_subchannel *selected;
   /** have we started picking? */
   int started_picking;
   /** are we shut down? */
@@ -76,24 +76,6 @@ typedef struct {
   grpc_connectivity_state_tracker state_tracker;
 } pick_first_lb_policy;
 
-static void del_interested_parties_locked(grpc_exec_ctx *exec_ctx,
-                                          pick_first_lb_policy *p) {
-  pending_pick *pp;
-  for (pp = p->pending_picks; pp; pp = pp->next) {
-    grpc_subchannel_del_interested_party(
-        exec_ctx, p->subchannels[p->checking_subchannel], pp->pollset);
-  }
-}
-
-static void add_interested_parties_locked(grpc_exec_ctx *exec_ctx,
-                                          pick_first_lb_policy *p) {
-  pending_pick *pp;
-  for (pp = p->pending_picks; pp; pp = pp->next) {
-    grpc_subchannel_add_interested_party(
-        exec_ctx, p->subchannels[p->checking_subchannel], pp->pollset);
-  }
-}
-
 void pf_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
   size_t i;
@@ -102,7 +84,7 @@ void pf_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
     GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[i], "pick_first");
   }
   if (p->selected) {
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, p->selected, "picked_first");
+    GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, p->selected, "picked_first");
   }
   grpc_connectivity_state_destroy(exec_ctx, &p->state_tracker);
   gpr_free(p->subchannels);
@@ -114,16 +96,26 @@ void pf_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
   pending_pick *pp;
   gpr_mu_lock(&p->mu);
-  del_interested_parties_locked(exec_ctx, p);
   p->shutdown = 1;
   pp = p->pending_picks;
   p->pending_picks = NULL;
   grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                               GRPC_CHANNEL_FATAL_FAILURE, "shutdown");
+  /* cancel subscription */
+  if (p->selected != NULL) {
+    grpc_connected_subchannel_notify_on_state_change(
+        exec_ctx, p->selected, NULL, NULL, &p->connectivity_changed);
+  } else {
+    grpc_subchannel_notify_on_state_change(
+        exec_ctx, p->subchannels[p->checking_subchannel], NULL, NULL,
+        &p->connectivity_changed);
+  }
   gpr_mu_unlock(&p->mu);
   while (pp != NULL) {
     pending_pick *next = pp->next;
     *pp->target = NULL;
+    grpc_pollset_set_del_pollset(exec_ctx, &p->base.interested_parties,
+                                 pp->pollset);
     grpc_exec_ctx_enqueue(exec_ctx, pp->on_complete, 1);
     gpr_free(pp);
     pp = next;
@@ -131,7 +123,7 @@ void pf_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
 }
 
 static void pf_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
-                           grpc_subchannel **target) {
+                           grpc_connected_subchannel **target) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
   pending_pick *pp;
   gpr_mu_lock(&p->mu);
@@ -140,8 +132,8 @@ static void pf_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
   while (pp != NULL) {
     pending_pick *next = pp->next;
     if (pp->target == target) {
-      grpc_subchannel_del_interested_party(
-          exec_ctx, p->subchannels[p->checking_subchannel], pp->pollset);
+      grpc_pollset_set_del_pollset(exec_ctx, &p->base.interested_parties,
+                                   pp->pollset);
       *target = NULL;
       grpc_exec_ctx_enqueue(exec_ctx, pp->on_complete, 0);
       gpr_free(pp);
@@ -158,10 +150,11 @@ static void start_picking(grpc_exec_ctx *exec_ctx, pick_first_lb_policy *p) {
   p->started_picking = 1;
   p->checking_subchannel = 0;
   p->checking_connectivity = GRPC_CHANNEL_IDLE;
-  GRPC_LB_POLICY_REF(&p->base, "pick_first_connectivity");
+  GRPC_LB_POLICY_WEAK_REF(&p->base, "pick_first_connectivity");
   grpc_subchannel_notify_on_state_change(
       exec_ctx, p->subchannels[p->checking_subchannel],
-      &p->checking_connectivity, &p->connectivity_changed);
+      &p->base.interested_parties, &p->checking_connectivity,
+      &p->connectivity_changed);
 }
 
 void pf_exit_idle(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
@@ -174,8 +167,8 @@ void pf_exit_idle(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
 }
 
 int pf_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, grpc_pollset *pollset,
-            grpc_metadata_batch *initial_metadata, grpc_subchannel **target,
-            grpc_closure *on_complete) {
+            grpc_metadata_batch *initial_metadata,
+            grpc_connected_subchannel **target, grpc_closure *on_complete) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
   pending_pick *pp;
   gpr_mu_lock(&p->mu);
@@ -187,8 +180,8 @@ int pf_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, grpc_pollset *pollset,
     if (!p->started_picking) {
       start_picking(exec_ctx, p);
     }
-    grpc_subchannel_add_interested_party(
-        exec_ctx, p->subchannels[p->checking_subchannel], pollset);
+    grpc_pollset_set_add_pollset(exec_ctx, &p->base.interested_parties,
+                                 pollset);
     pp = gpr_malloc(sizeof(*pp));
     pp->next = p->pending_picks;
     pp->pollset = pollset;
@@ -204,25 +197,17 @@ static void destroy_subchannels(grpc_exec_ctx *exec_ctx, void *arg,
                                 int iomgr_success) {
   pick_first_lb_policy *p = arg;
   size_t i;
-  grpc_transport_op op;
   size_t num_subchannels = p->num_subchannels;
   grpc_subchannel **subchannels;
-  grpc_subchannel *exclude_subchannel;
 
   gpr_mu_lock(&p->mu);
   subchannels = p->subchannels;
   p->num_subchannels = 0;
   p->subchannels = NULL;
-  exclude_subchannel = p->selected;
   gpr_mu_unlock(&p->mu);
-  GRPC_LB_POLICY_UNREF(exec_ctx, &p->base, "destroy_subchannels");
+  GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "destroy_subchannels");
 
   for (i = 0; i < num_subchannels; i++) {
-    if (subchannels[i] != exclude_subchannel) {
-      memset(&op, 0, sizeof(op));
-      op.disconnect = 1;
-      grpc_subchannel_process_transport_op(exec_ctx, subchannels[i], &op);
-    }
     GRPC_SUBCHANNEL_UNREF(exec_ctx, subchannels[i], "pick_first");
   }
 
@@ -232,23 +217,28 @@ static void destroy_subchannels(grpc_exec_ctx *exec_ctx, void *arg,
 static void pf_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
                                     int iomgr_success) {
   pick_first_lb_policy *p = arg;
+  grpc_subchannel *selected_subchannel;
   pending_pick *pp;
 
   gpr_mu_lock(&p->mu);
 
   if (p->shutdown) {
     gpr_mu_unlock(&p->mu);
-    GRPC_LB_POLICY_UNREF(exec_ctx, &p->base, "pick_first_connectivity");
+    GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "pick_first_connectivity");
     return;
   } else if (p->selected != NULL) {
+    if (p->checking_connectivity == GRPC_CHANNEL_TRANSIENT_FAILURE) {
+      /* if the selected channel goes bad, we're done */
+      p->checking_connectivity = GRPC_CHANNEL_FATAL_FAILURE;
+    }
     grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                 p->checking_connectivity, "selected_changed");
     if (p->checking_connectivity != GRPC_CHANNEL_FATAL_FAILURE) {
-      grpc_subchannel_notify_on_state_change(exec_ctx, p->selected,
-                                             &p->checking_connectivity,
-                                             &p->connectivity_changed);
+      grpc_connected_subchannel_notify_on_state_change(
+          exec_ctx, p->selected, &p->base.interested_parties,
+          &p->checking_connectivity, &p->connectivity_changed);
     } else {
-      GRPC_LB_POLICY_UNREF(exec_ctx, &p->base, "pick_first_connectivity");
+      GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "pick_first_connectivity");
     }
   } else {
   loop:
@@ -256,39 +246,41 @@ static void pf_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
       case GRPC_CHANNEL_READY:
         grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                     GRPC_CHANNEL_READY, "connecting_ready");
-        p->selected = p->subchannels[p->checking_subchannel];
-        GRPC_SUBCHANNEL_REF(p->selected, "picked_first");
+        selected_subchannel = p->subchannels[p->checking_subchannel];
+        p->selected =
+            grpc_subchannel_get_connected_subchannel(selected_subchannel);
+        GPR_ASSERT(p->selected);
+        GRPC_CONNECTED_SUBCHANNEL_REF(p->selected, "picked_first");
         /* drop the pick list: we are connected now */
-        GRPC_LB_POLICY_REF(&p->base, "destroy_subchannels");
+        GRPC_LB_POLICY_WEAK_REF(&p->base, "destroy_subchannels");
         grpc_exec_ctx_enqueue(exec_ctx,
                               grpc_closure_create(destroy_subchannels, p), 1);
         /* update any calls that were waiting for a pick */
         while ((pp = p->pending_picks)) {
           p->pending_picks = pp->next;
           *pp->target = p->selected;
-          grpc_subchannel_del_interested_party(exec_ctx, p->selected,
-                                               pp->pollset);
+          grpc_pollset_set_del_pollset(exec_ctx, &p->base.interested_parties,
+                                       pp->pollset);
           grpc_exec_ctx_enqueue(exec_ctx, pp->on_complete, 1);
           gpr_free(pp);
         }
-        grpc_subchannel_notify_on_state_change(exec_ctx, p->selected,
-                                               &p->checking_connectivity,
-                                               &p->connectivity_changed);
+        grpc_connected_subchannel_notify_on_state_change(
+            exec_ctx, p->selected, &p->base.interested_parties,
+            &p->checking_connectivity, &p->connectivity_changed);
         break;
       case GRPC_CHANNEL_TRANSIENT_FAILURE:
         grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                     GRPC_CHANNEL_TRANSIENT_FAILURE,
                                     "connecting_transient_failure");
-        del_interested_parties_locked(exec_ctx, p);
         p->checking_subchannel =
             (p->checking_subchannel + 1) % p->num_subchannels;
         p->checking_connectivity = grpc_subchannel_check_connectivity(
             p->subchannels[p->checking_subchannel]);
-        add_interested_parties_locked(exec_ctx, p);
         if (p->checking_connectivity == GRPC_CHANNEL_TRANSIENT_FAILURE) {
           grpc_subchannel_notify_on_state_change(
               exec_ctx, p->subchannels[p->checking_subchannel],
-              &p->checking_connectivity, &p->connectivity_changed);
+              &p->base.interested_parties, &p->checking_connectivity,
+              &p->connectivity_changed);
         } else {
           goto loop;
         }
@@ -300,13 +292,13 @@ static void pf_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
                                     "connecting_changed");
         grpc_subchannel_notify_on_state_change(
             exec_ctx, p->subchannels[p->checking_subchannel],
-            &p->checking_connectivity, &p->connectivity_changed);
+            &p->base.interested_parties, &p->checking_connectivity,
+            &p->connectivity_changed);
         break;
       case GRPC_CHANNEL_FATAL_FAILURE:
-        del_interested_parties_locked(exec_ctx, p);
-        GPR_SWAP(grpc_subchannel *, p->subchannels[p->checking_subchannel],
-                 p->subchannels[p->num_subchannels - 1]);
         p->num_subchannels--;
+        GPR_SWAP(grpc_subchannel *, p->subchannels[p->checking_subchannel],
+                 p->subchannels[p->num_subchannels]);
         GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[p->num_subchannels],
                               "pick_first");
         if (p->num_subchannels == 0) {
@@ -319,7 +311,8 @@ static void pf_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
             grpc_exec_ctx_enqueue(exec_ctx, pp->on_complete, 1);
             gpr_free(pp);
           }
-          GRPC_LB_POLICY_UNREF(exec_ctx, &p->base, "pick_first_connectivity");
+          GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base,
+                                    "pick_first_connectivity");
         } else {
           grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                       GRPC_CHANNEL_TRANSIENT_FAILURE,
@@ -327,7 +320,6 @@ static void pf_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
           p->checking_subchannel %= p->num_subchannels;
           p->checking_connectivity = grpc_subchannel_check_connectivity(
               p->subchannels[p->checking_subchannel]);
-          add_interested_parties_locked(exec_ctx, p);
           goto loop;
         }
     }
@@ -336,39 +328,6 @@ static void pf_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
   gpr_mu_unlock(&p->mu);
 }
 
-static void pf_broadcast(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
-                         grpc_transport_op *op) {
-  pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
-  size_t i;
-  size_t n;
-  grpc_subchannel **subchannels;
-  grpc_subchannel *selected;
-
-  gpr_mu_lock(&p->mu);
-  n = p->num_subchannels;
-  subchannels = gpr_malloc(n * sizeof(*subchannels));
-  selected = p->selected;
-  if (selected) {
-    GRPC_SUBCHANNEL_REF(selected, "pf_broadcast_to_selected");
-  }
-  for (i = 0; i < n; i++) {
-    subchannels[i] = p->subchannels[i];
-    GRPC_SUBCHANNEL_REF(subchannels[i], "pf_broadcast");
-  }
-  gpr_mu_unlock(&p->mu);
-
-  for (i = 0; i < n; i++) {
-    if (selected == subchannels[i]) continue;
-    grpc_subchannel_process_transport_op(exec_ctx, subchannels[i], op);
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, subchannels[i], "pf_broadcast");
-  }
-  if (p->selected) {
-    grpc_subchannel_process_transport_op(exec_ctx, selected, op);
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, selected, "pf_broadcast_to_selected");
-  }
-  gpr_free(subchannels);
-}
-
 static grpc_connectivity_state pf_check_connectivity(grpc_exec_ctx *exec_ctx,
                                                      grpc_lb_policy *pol) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
@@ -389,9 +348,21 @@ void pf_notify_on_state_change(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
   gpr_mu_unlock(&p->mu);
 }
 
+void pf_ping_one(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
+                 grpc_closure *closure) {
+  pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
+  gpr_mu_lock(&p->mu);
+  if (p->selected) {
+    grpc_connected_subchannel_ping(exec_ctx, p->selected, closure);
+  } else {
+    grpc_exec_ctx_enqueue(exec_ctx, closure, 0);
+  }
+  gpr_mu_unlock(&p->mu);
+}
+
 static const grpc_lb_policy_vtable pick_first_lb_policy_vtable = {
-    pf_destroy, pf_shutdown, pf_pick, pf_cancel_pick, pf_exit_idle,
-    pf_broadcast, pf_check_connectivity, pf_notify_on_state_change};
+    pf_destroy, pf_shutdown, pf_pick, pf_cancel_pick, pf_ping_one, pf_exit_idle,
+    pf_check_connectivity, pf_notify_on_state_change};
 
 static void pick_first_factory_ref(grpc_lb_policy_factory *factory) {}
 

src/core/client_config/lb_policies/round_robin.c

@@ -38,6 +38,8 @@
 #include <grpc/support/alloc.h>
 #include "src/core/transport/connectivity_state.h"
 
+typedef struct round_robin_lb_policy round_robin_lb_policy;
+
 int grpc_lb_round_robin_trace = 0;
 
 /** List of entities waiting for a pick.
@@ -46,7 +48,7 @@ int grpc_lb_round_robin_trace = 0;
 typedef struct pending_pick {
   struct pending_pick *next;
   grpc_pollset *pollset;
-  grpc_subchannel **target;
+  grpc_connected_subchannel **target;
   grpc_closure *on_complete;
 } pending_pick;
 
@@ -58,22 +60,27 @@ typedef struct ready_list {
 } ready_list;
 
 typedef struct {
-  size_t subchannel_idx; /**< Index over p->subchannels */
-  void *p;               /**< round_robin_lb_policy instance */
-} connectivity_changed_cb_arg;
-
-typedef struct {
+  /** index within policy->subchannels */
+  size_t index;
+  /** backpointer to owning policy */
+  round_robin_lb_policy *policy;
+  /** subchannel itself */
+  grpc_subchannel *subchannel;
+  /** notification that connectivity has changed on subchannel */
+  grpc_closure connectivity_changed_closure;
+  /** this subchannels current position in subchannel->ready_list */
+  ready_list *ready_list_node;
+  /** last observed connectivity */
+  grpc_connectivity_state connectivity_state;
+} subchannel_data;
+
+struct round_robin_lb_policy {
   /** base policy: must be first */
   grpc_lb_policy base;
 
   /** all our subchannels */
-  grpc_subchannel **subchannels;
   size_t num_subchannels;
-
-  /** Callbacks, one per subchannel being watched, to be called when their
-   * respective connectivity changes */
-  grpc_closure *connectivity_changed_cbs;
-  connectivity_changed_cb_arg *cb_args;
+  subchannel_data **subchannels;
 
   /** mutex protecting remaining members */
   gpr_mu mu;
@@ -81,8 +88,6 @@ typedef struct {
   int started_picking;
   /** are we shutting down? */
   int shutdown;
-  /** Connectivity state of the subchannels being watched */
-  grpc_connectivity_state *subchannel_connectivity;
   /** List of picks that are waiting on connectivity */
   pending_pick *pending_picks;
 
@@ -93,13 +98,7 @@ typedef struct {
   ready_list ready_list;
   /** Last pick from the ready list. */
   ready_list *ready_list_last_pick;
-
-  /** Subchannel index to ready_list node.
-   *
-   * Kept in order to remove nodes from the ready list associated with a
-   * subchannel */
-  ready_list **subchannel_index_to_readylist_node;
-} round_robin_lb_policy;
+};
 
 /** Returns the next subchannel from the connected list or NULL if the list is
  * empty.
@@ -144,9 +143,9 @@ static void advance_last_picked_locked(round_robin_lb_policy *p) {
 /** Prepends (relative to the root at p->ready_list) the connected subchannel \a
  * csc to the list of ready subchannels. */
 static ready_list *add_connected_sc_locked(round_robin_lb_policy *p,
-                                           grpc_subchannel *csc) {
+                                           grpc_subchannel *sc) {
   ready_list *new_elem = gpr_malloc(sizeof(ready_list));
-  new_elem->subchannel = csc;
+  new_elem->subchannel = sc;
   if (p->ready_list.prev == NULL) {
     /* first element */
     new_elem->next = &p->ready_list;
@@ -160,7 +159,7 @@ static ready_list *add_connected_sc_locked(round_robin_lb_policy *p,
     p->ready_list.prev = new_elem;
   }
   if (grpc_lb_round_robin_trace) {
-    gpr_log(GPR_DEBUG, "[READYLIST] ADDING NODE %p (SC %p)", new_elem, csc);
+    gpr_log(GPR_DEBUG, "[READYLIST] ADDING NODE %p (SC %p)", new_elem, sc);
   }
   return new_elem;
 }
@@ -200,28 +199,15 @@ static void remove_disconnected_sc_locked(round_robin_lb_policy *p,
   gpr_free(node);
 }
 
-static void del_interested_parties_locked(grpc_exec_ctx *exec_ctx,
-                                          round_robin_lb_policy *p,
-                                          const size_t subchannel_idx) {
-  pending_pick *pp;
-  for (pp = p->pending_picks; pp; pp = pp->next) {
-    grpc_subchannel_del_interested_party(
-        exec_ctx, p->subchannels[subchannel_idx], pp->pollset);
-  }
-}
-
 void rr_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
   size_t i;
   ready_list *elem;
   for (i = 0; i < p->num_subchannels; i++) {
-    del_interested_parties_locked(exec_ctx, p, i);
-  }
-  for (i = 0; i < p->num_subchannels; i++) {
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[i], "round_robin");
+    subchannel_data *sd = p->subchannels[i];
+    GRPC_SUBCHANNEL_UNREF(exec_ctx, sd->subchannel, "round_robin");
+    gpr_free(sd);
   }
-  gpr_free(p->connectivity_changed_cbs);
-  gpr_free(p->subchannel_connectivity);
 
   grpc_connectivity_state_destroy(exec_ctx, &p->state_tracker);
   gpr_free(p->subchannels);
@@ -237,20 +223,15 @@ void rr_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
     gpr_free(elem);
     elem = tmp;
   }
-  gpr_free(p->subchannel_index_to_readylist_node);
-  gpr_free(p->cb_args);
   gpr_free(p);
 }
 
 void rr_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
-  size_t i;
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
   pending_pick *pp;
-  gpr_mu_lock(&p->mu);
+  size_t i;
 
-  for (i = 0; i < p->num_subchannels; i++) {
-    del_interested_parties_locked(exec_ctx, p, i);
-  }
+  gpr_mu_lock(&p->mu);
 
   p->shutdown = 1;
   while ((pp = p->pending_picks)) {
@@ -261,24 +242,26 @@ void rr_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   }
   grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                               GRPC_CHANNEL_FATAL_FAILURE, "shutdown");
+  for (i = 0; i < p->num_subchannels; i++) {
+    subchannel_data *sd = p->subchannels[i];
+    grpc_subchannel_notify_on_state_change(exec_ctx, sd->subchannel, NULL, NULL,
+                                           &sd->connectivity_changed_closure);
+  }
   gpr_mu_unlock(&p->mu);
 }
 
 static void rr_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
-                           grpc_subchannel **target) {
+                           grpc_connected_subchannel **target) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
   pending_pick *pp;
-  size_t i;
   gpr_mu_lock(&p->mu);
   pp = p->pending_picks;
   p->pending_picks = NULL;
   while (pp != NULL) {
     pending_pick *next = pp->next;
     if (pp->target == target) {
-      for (i = 0; i < p->num_subchannels; i++) {
-        grpc_subchannel_add_interested_party(exec_ctx, p->subchannels[i],
-                                             pp->pollset);
-      }
+      grpc_pollset_set_del_pollset(exec_ctx, &p->base.interested_parties,
+                                   pp->pollset);
       *target = NULL;
       grpc_exec_ctx_enqueue(exec_ctx, pp->on_complete, 0);
       gpr_free(pp);
@@ -295,12 +278,16 @@ static void start_picking(grpc_exec_ctx *exec_ctx, round_robin_lb_policy *p) {
   size_t i;
   p->started_picking = 1;
 
+  gpr_log(GPR_DEBUG, "LB_POLICY: p=%p num_subchannels=%d", p,
+          p->num_subchannels);
+
   for (i = 0; i < p->num_subchannels; i++) {
-    p->subchannel_connectivity[i] = GRPC_CHANNEL_IDLE;
-    grpc_subchannel_notify_on_state_change(exec_ctx, p->subchannels[i],
-                                           &p->subchannel_connectivity[i],
-                                           &p->connectivity_changed_cbs[i]);
-    GRPC_LB_POLICY_REF(&p->base, "round_robin_connectivity");
+    subchannel_data *sd = p->subchannels[i];
+    sd->connectivity_state = GRPC_CHANNEL_IDLE;
+    grpc_subchannel_notify_on_state_change(
+        exec_ctx, sd->subchannel, &p->base.interested_parties,
+        &sd->connectivity_state, &sd->connectivity_changed_closure);
+    GRPC_LB_POLICY_WEAK_REF(&p->base, "round_robin_connectivity");
   }
 }
 
@@ -314,18 +301,18 @@ void rr_exit_idle(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
 }
 
 int rr_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, grpc_pollset *pollset,
-            grpc_metadata_batch *initial_metadata, grpc_subchannel **target,
-            grpc_closure *on_complete) {
-  size_t i;
+            grpc_metadata_batch *initial_metadata,
+            grpc_connected_subchannel **target, grpc_closure *on_complete) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
   pending_pick *pp;
   ready_list *selected;
   gpr_mu_lock(&p->mu);
   if ((selected = peek_next_connected_locked(p))) {
     gpr_mu_unlock(&p->mu);
-    *target = selected->subchannel;
+    *target = grpc_subchannel_get_connected_subchannel(selected->subchannel);
     if (grpc_lb_round_robin_trace) {
-      gpr_log(GPR_DEBUG, "[RR PICK] TARGET <-- SUBCHANNEL %p (NODE %p)",
+      gpr_log(GPR_DEBUG,
+              "[RR PICK] TARGET <-- CONNECTED SUBCHANNEL %p (NODE %p)",
               selected->subchannel, selected);
     }
     /* only advance the last picked pointer if the selection was used */
@@ -335,10 +322,8 @@ int rr_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, grpc_pollset *pollset,
     if (!p->started_picking) {
       start_picking(exec_ctx, p);
     }
-    for (i = 0; i < p->num_subchannels; i++) {
-      grpc_subchannel_add_interested_party(exec_ctx, p->subchannels[i],
-                                           pollset);
-    }
+    grpc_pollset_set_add_pollset(exec_ctx, &p->base.interested_parties,
+                                 pollset);
     pp = gpr_malloc(sizeof(*pp));
     pp->next = p->pending_picks;
     pp->pollset = pollset;
@@ -352,33 +337,25 @@ int rr_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, grpc_pollset *pollset,
 
 static void rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
                                     int iomgr_success) {
-  connectivity_changed_cb_arg *cb_arg = arg;
-  round_robin_lb_policy *p = cb_arg->p;
-  /* index over p->subchannels of this cb's subchannel */
-  const size_t this_idx = cb_arg->subchannel_idx;
+  subchannel_data *sd = arg;
+  round_robin_lb_policy *p = sd->policy;
   pending_pick *pp;
   ready_list *selected;
 
   int unref = 0;
 
-  /* connectivity state of this cb's subchannel */
-  grpc_connectivity_state *this_connectivity;
-
   gpr_mu_lock(&p->mu);
 
-  this_connectivity = &p->subchannel_connectivity[this_idx];
-
   if (p->shutdown) {
     unref = 1;
   } else {
-    switch (*this_connectivity) {
+    switch (sd->connectivity_state) {
       case GRPC_CHANNEL_READY:
         grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                     GRPC_CHANNEL_READY, "connecting_ready");
         /* add the newly connected subchannel to the list of connected ones.
          * Note that it goes to the "end of the line". */
-        p->subchannel_index_to_readylist_node[this_idx] =
-            add_connected_sc_locked(p, p->subchannels[this_idx]);
+        sd->ready_list_node = add_connected_sc_locked(p, sd->subchannel);
         /* at this point we know there's at least one suitable subchannel. Go
          * ahead and pick one and notify the pending suitors in
          * p->pending_picks. This preemtively replicates rr_pick()'s actions. */
@@ -390,60 +367,60 @@ static void rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
         }
         while ((pp = p->pending_picks)) {
           p->pending_picks = pp->next;
-          *pp->target = selected->subchannel;
+          *pp->target =
+              grpc_subchannel_get_connected_subchannel(selected->subchannel);
           if (grpc_lb_round_robin_trace) {
             gpr_log(GPR_DEBUG,
                     "[RR CONN CHANGED] TARGET <-- SUBCHANNEL %p (NODE %p)",
                     selected->subchannel, selected);
           }
-          grpc_subchannel_del_interested_party(exec_ctx, selected->subchannel,
-                                               pp->pollset);
+          grpc_pollset_set_del_pollset(exec_ctx, &p->base.interested_parties,
+                                       pp->pollset);
           grpc_exec_ctx_enqueue(exec_ctx, pp->on_complete, 1);
           gpr_free(pp);
         }
         grpc_subchannel_notify_on_state_change(
-            exec_ctx, p->subchannels[this_idx], this_connectivity,
-            &p->connectivity_changed_cbs[this_idx]);
+            exec_ctx, sd->subchannel, &p->base.interested_parties,
+            &sd->connectivity_state, &sd->connectivity_changed_closure);
         break;
       case GRPC_CHANNEL_CONNECTING:
       case GRPC_CHANNEL_IDLE:
         grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
-                                    *this_connectivity, "connecting_changed");
+                                    sd->connectivity_state,
+                                    "connecting_changed");
         grpc_subchannel_notify_on_state_change(
-            exec_ctx, p->subchannels[this_idx], this_connectivity,
-            &p->connectivity_changed_cbs[this_idx]);
+            exec_ctx, sd->subchannel, &p->base.interested_parties,
+            &sd->connectivity_state, &sd->connectivity_changed_closure);
         break;
       case GRPC_CHANNEL_TRANSIENT_FAILURE:
-        del_interested_parties_locked(exec_ctx, p, this_idx);
         /* renew state notification */
         grpc_subchannel_notify_on_state_change(
-            exec_ctx, p->subchannels[this_idx], this_connectivity,
-            &p->connectivity_changed_cbs[this_idx]);
+            exec_ctx, sd->subchannel, &p->base.interested_parties,
+            &sd->connectivity_state, &sd->connectivity_changed_closure);
 
         /* remove from ready list if still present */
-        if (p->subchannel_index_to_readylist_node[this_idx] != NULL) {
-          remove_disconnected_sc_locked(
-              p, p->subchannel_index_to_readylist_node[this_idx]);
-          p->subchannel_index_to_readylist_node[this_idx] = NULL;
+        if (sd->ready_list_node != NULL) {
+          remove_disconnected_sc_locked(p, sd->ready_list_node);
+          sd->ready_list_node = NULL;
         }
         grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                     GRPC_CHANNEL_TRANSIENT_FAILURE,
                                     "connecting_transient_failure");
         break;
       case GRPC_CHANNEL_FATAL_FAILURE:
-        del_interested_parties_locked(exec_ctx, p, this_idx);
-        if (p->subchannel_index_to_readylist_node[this_idx] != NULL) {
-          remove_disconnected_sc_locked(
-              p, p->subchannel_index_to_readylist_node[this_idx]);
-          p->subchannel_index_to_readylist_node[this_idx] = NULL;
+        if (sd->ready_list_node != NULL) {
+          remove_disconnected_sc_locked(p, sd->ready_list_node);
+          sd->ready_list_node = NULL;
         }
 
-        GPR_SWAP(grpc_subchannel *, p->subchannels[this_idx],
-                 p->subchannels[p->num_subchannels - 1]);
         p->num_subchannels--;
-        GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[p->num_subchannels],
-                              "round_robin");
+        GPR_SWAP(subchannel_data *, p->subchannels[sd->index],
+                 p->subchannels[p->num_subchannels]);
+        GRPC_SUBCHANNEL_UNREF(exec_ctx, sd->subchannel, "round_robin");
+        p->subchannels[sd->index]->index = sd->index;
+        gpr_free(sd);
 
+        unref = 1;
         if (p->num_subchannels == 0) {
           grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                       GRPC_CHANNEL_FATAL_FAILURE,
@@ -454,7 +431,6 @@ static void rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
             grpc_exec_ctx_enqueue(exec_ctx, pp->on_complete, 1);
             gpr_free(pp);
           }
-          unref = 1;
         } else {
           grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                       GRPC_CHANNEL_TRANSIENT_FAILURE,
@@ -466,31 +442,8 @@ static void rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
   gpr_mu_unlock(&p->mu);
 
   if (unref) {
-    GRPC_LB_POLICY_UNREF(exec_ctx, &p->base, "round_robin_connectivity");
-  }
-}
-
-static void rr_broadcast(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
-                         grpc_transport_op *op) {
-  round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
-  size_t i;
-  size_t n;
-  grpc_subchannel **subchannels;
-
-  gpr_mu_lock(&p->mu);
-  n = p->num_subchannels;
-  subchannels = gpr_malloc(n * sizeof(*subchannels));
-  for (i = 0; i < n; i++) {
-    subchannels[i] = p->subchannels[i];
-    GRPC_SUBCHANNEL_REF(subchannels[i], "rr_broadcast");
-  }
-  gpr_mu_unlock(&p->mu);
-
-  for (i = 0; i < n; i++) {
-    grpc_subchannel_process_transport_op(exec_ctx, subchannels[i], op);
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, subchannels[i], "rr_broadcast");
+    GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "round_robin_connectivity");
   }
-  gpr_free(subchannels);
 }
 
 static grpc_connectivity_state rr_check_connectivity(grpc_exec_ctx *exec_ctx,
@@ -514,9 +467,25 @@ static void rr_notify_on_state_change(grpc_exec_ctx *exec_ctx,
   gpr_mu_unlock(&p->mu);
 }
 
+static void rr_ping_one(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
+                        grpc_closure *closure) {
+  round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
+  ready_list *selected;
+  grpc_connected_subchannel *target;
+  gpr_mu_lock(&p->mu);
+  if ((selected = peek_next_connected_locked(p))) {
+    gpr_mu_unlock(&p->mu);
+    target = grpc_subchannel_get_connected_subchannel(selected->subchannel);
+    grpc_connected_subchannel_ping(exec_ctx, target, closure);
+  } else {
+    gpr_mu_unlock(&p->mu);
+    grpc_exec_ctx_enqueue(exec_ctx, closure, 0);
+  }
+}
+
 static const grpc_lb_policy_vtable round_robin_lb_policy_vtable = {
-    rr_destroy, rr_shutdown, rr_pick, rr_cancel_pick, rr_exit_idle,
-    rr_broadcast, rr_check_connectivity, rr_notify_on_state_change};
+    rr_destroy, rr_shutdown, rr_pick, rr_cancel_pick, rr_ping_one, rr_exit_idle,
+    rr_check_connectivity, rr_notify_on_state_change};
 
 static void round_robin_factory_ref(grpc_lb_policy_factory *factory) {}
 
@@ -529,27 +498,22 @@ static grpc_lb_policy *create_round_robin(grpc_lb_policy_factory *factory,
   GPR_ASSERT(args->num_subchannels > 0);
   memset(p, 0, sizeof(*p));
   grpc_lb_policy_init(&p->base, &round_robin_lb_policy_vtable);
-  p->subchannels =
-      gpr_malloc(sizeof(grpc_subchannel *) * args->num_subchannels);
   p->num_subchannels = args->num_subchannels;
+  p->subchannels = gpr_malloc(sizeof(*p->subchannels) * p->num_subchannels);
+  memset(p->subchannels, 0, sizeof(*p->subchannels) * p->num_subchannels);
   grpc_connectivity_state_init(&p->state_tracker, GRPC_CHANNEL_IDLE,
                                "round_robin");
-  memcpy(p->subchannels, args->subchannels,
-         sizeof(grpc_subchannel *) * args->num_subchannels);
 
   gpr_mu_init(&p->mu);
-  p->connectivity_changed_cbs =
-      gpr_malloc(sizeof(grpc_closure) * args->num_subchannels);
-  p->subchannel_connectivity =
-      gpr_malloc(sizeof(grpc_connectivity_state) * args->num_subchannels);
-
-  p->cb_args =
-      gpr_malloc(sizeof(connectivity_changed_cb_arg) * args->num_subchannels);
   for (i = 0; i < args->num_subchannels; i++) {
-    p->cb_args[i].subchannel_idx = i;
-    p->cb_args[i].p = p;
-    grpc_closure_init(&p->connectivity_changed_cbs[i], rr_connectivity_changed,
-                      &p->cb_args[i]);
+    subchannel_data *sd = gpr_malloc(sizeof(*sd));
+    memset(sd, 0, sizeof(*sd));
+    p->subchannels[i] = sd;
+    sd->policy = p;
+    sd->index = i;
+    sd->subchannel = args->subchannels[i];
+    grpc_closure_init(&sd->connectivity_changed_closure,
+                      rr_connectivity_changed, sd);
   }
 
   /* The (dummy node) root of the ready list */
@@ -558,10 +522,6 @@ static grpc_lb_policy *create_round_robin(grpc_lb_policy_factory *factory,
   p->ready_list.next = NULL;
   p->ready_list_last_pick = &p->ready_list;
 
-  p->subchannel_index_to_readylist_node =
-      gpr_malloc(sizeof(grpc_subchannel *) * args->num_subchannels);
-  memset(p->subchannel_index_to_readylist_node, 0,
-         sizeof(grpc_subchannel *) * args->num_subchannels);
   return &p->base;
 }
 

src/core/client_config/lb_policy.c

@@ -33,63 +33,94 @@
 
 #include "src/core/client_config/lb_policy.h"
 
+#define WEAK_REF_BITS 16
+
 void grpc_lb_policy_init(grpc_lb_policy *policy,
                          const grpc_lb_policy_vtable *vtable) {
   policy->vtable = vtable;
-  gpr_ref_init(&policy->refs, 1);
+  gpr_atm_no_barrier_store(&policy->ref_pair, 1 << WEAK_REF_BITS);
+  grpc_pollset_set_init(&policy->interested_parties);
 }
 
 #ifdef GRPC_LB_POLICY_REFCOUNT_DEBUG
-void grpc_lb_policy_ref(grpc_lb_policy *policy, const char *file, int line,
-                        const char *reason) {
-  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "LB_POLICY:%p   ref %d -> %d %s",
-          policy, (int)policy->refs.count, (int)policy->refs.count + 1, reason);
+#define REF_FUNC_EXTRA_ARGS , const char *file, int line, const char *reason
+#define REF_MUTATE_EXTRA_ARGS REF_FUNC_EXTRA_ARGS, const char *purpose
+#define REF_FUNC_PASS_ARGS(new_reason) , file, line, new_reason
+#define REF_MUTATE_PASS_ARGS(purpose) , file, line, reason, purpose
 #else
-void grpc_lb_policy_ref(grpc_lb_policy *policy) {
+#define REF_FUNC_EXTRA_ARGS
+#define REF_MUTATE_EXTRA_ARGS
+#define REF_FUNC_PASS_ARGS(new_reason)
+#define REF_MUTATE_PASS_ARGS(x)
 #endif
-  gpr_ref(&policy->refs);
-}
 
+static gpr_atm ref_mutate(grpc_lb_policy *c, gpr_atm delta,
+                          int barrier REF_MUTATE_EXTRA_ARGS) {
+  gpr_atm old_val = barrier ? gpr_atm_full_fetch_add(&c->ref_pair, delta)
+                            : gpr_atm_no_barrier_fetch_add(&c->ref_pair, delta);
 #ifdef GRPC_LB_POLICY_REFCOUNT_DEBUG
-void grpc_lb_policy_unref(grpc_lb_policy *policy,
-                          grpc_closure_list *closure_list, const char *file,
-                          int line, const char *reason) {
-  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "LB_POLICY:%p unref %d -> %d %s",
-          policy, (int)policy->refs.count, (int)policy->refs.count - 1, reason);
-#else
-void grpc_lb_policy_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy) {
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+          "LB_POLICY: %p % 12s 0x%08x -> 0x%08x [%s]", c, purpose, old_val,
+          old_val + delta, reason);
 #endif
-  if (gpr_unref(&policy->refs)) {
-    policy->vtable->destroy(exec_ctx, policy);
+  return old_val;
+}
+
+void grpc_lb_policy_ref(grpc_lb_policy *policy REF_FUNC_EXTRA_ARGS) {
+  ref_mutate(policy, 1 << WEAK_REF_BITS, 0 REF_MUTATE_PASS_ARGS("STRONG_REF"));
+}
+
+void grpc_lb_policy_unref(grpc_exec_ctx *exec_ctx,
+                          grpc_lb_policy *policy REF_FUNC_EXTRA_ARGS) {
+  gpr_atm old_val =
+      ref_mutate(policy, (gpr_atm)1 - (gpr_atm)(1 << WEAK_REF_BITS),
+                 1 REF_MUTATE_PASS_ARGS("STRONG_UNREF"));
+  gpr_atm mask = ~(gpr_atm)((1 << WEAK_REF_BITS) - 1);
+  gpr_atm check = 1 << WEAK_REF_BITS;
+  if ((old_val & mask) == check) {
+    policy->vtable->shutdown(exec_ctx, policy);
   }
+  grpc_lb_policy_weak_unref(exec_ctx,
+                            policy REF_FUNC_PASS_ARGS("strong-unref"));
 }
 
-void grpc_lb_policy_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy) {
-  policy->vtable->shutdown(exec_ctx, policy);
+void grpc_lb_policy_weak_ref(grpc_lb_policy *policy REF_FUNC_EXTRA_ARGS) {
+  ref_mutate(policy, 1, 0 REF_MUTATE_PASS_ARGS("WEAK_REF"));
+}
+
+void grpc_lb_policy_weak_unref(grpc_exec_ctx *exec_ctx,
+                               grpc_lb_policy *policy REF_FUNC_EXTRA_ARGS) {
+  gpr_atm old_val =
+      ref_mutate(policy, -(gpr_atm)1, 1 REF_MUTATE_PASS_ARGS("WEAK_UNREF"));
+  if (old_val == 1) {
+    grpc_pollset_set_destroy(&policy->interested_parties);
+    policy->vtable->destroy(exec_ctx, policy);
+  }
 }
 
 int grpc_lb_policy_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
                         grpc_pollset *pollset,
                         grpc_metadata_batch *initial_metadata,
-                        grpc_subchannel **target, grpc_closure *on_complete) {
+                        grpc_connected_subchannel **target,
+                        grpc_closure *on_complete) {
   return policy->vtable->pick(exec_ctx, policy, pollset, initial_metadata,
                               target, on_complete);
 }
 
 void grpc_lb_policy_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
-                                grpc_subchannel **target) {
+                                grpc_connected_subchannel **target) {
   policy->vtable->cancel_pick(exec_ctx, policy, target);
 }
 
-void grpc_lb_policy_broadcast(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
-                              grpc_transport_op *op) {
-  policy->vtable->broadcast(exec_ctx, policy, op);
-}
-
 void grpc_lb_policy_exit_idle(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy) {
   policy->vtable->exit_idle(exec_ctx, policy);
 }
 
+void grpc_lb_policy_ping_one(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+                             grpc_closure *closure) {
+  policy->vtable->ping_one(exec_ctx, policy, closure);
+}
+
 void grpc_lb_policy_notify_on_state_change(grpc_exec_ctx *exec_ctx,
                                            grpc_lb_policy *policy,
                                            grpc_connectivity_state *state,

src/core/client_config/lb_policy.h

@@ -47,7 +47,8 @@ typedef void (*grpc_lb_completion)(void *cb_arg, grpc_subchannel *subchannel,
 
 struct grpc_lb_policy {
   const grpc_lb_policy_vtable *vtable;
-  gpr_refcount refs;
+  gpr_atm ref_pair;
+  grpc_pollset_set interested_parties;
 };
 
 struct grpc_lb_policy_vtable {
@@ -58,17 +59,16 @@ struct grpc_lb_policy_vtable {
   /** implement grpc_lb_policy_pick */
   int (*pick)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
               grpc_pollset *pollset, grpc_metadata_batch *initial_metadata,
-              grpc_subchannel **target, grpc_closure *on_complete);
+              grpc_connected_subchannel **target, grpc_closure *on_complete);
   void (*cancel_pick)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
-                      grpc_subchannel **target);
+                      grpc_connected_subchannel **target);
+
+  void (*ping_one)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+                   grpc_closure *closure);
 
   /** try to enter a READY connectivity state */
   void (*exit_idle)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy);
 
-  /** broadcast a transport op to all subchannels */
-  void (*broadcast)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
-                    grpc_transport_op *op);
-
   /** check the current connectivity of the lb_policy */
   grpc_connectivity_state (*check_connectivity)(grpc_exec_ctx *exec_ctx,
                                                 grpc_lb_policy *policy);
@@ -81,29 +81,39 @@ struct grpc_lb_policy_vtable {
                                  grpc_closure *closure);
 };
 
+/*#define GRPC_LB_POLICY_REFCOUNT_DEBUG*/
 #ifdef GRPC_LB_POLICY_REFCOUNT_DEBUG
 #define GRPC_LB_POLICY_REF(p, r) \
   grpc_lb_policy_ref((p), __FILE__, __LINE__, (r))
 #define GRPC_LB_POLICY_UNREF(exec_ctx, p, r) \
   grpc_lb_policy_unref((exec_ctx), (p), __FILE__, __LINE__, (r))
+#define GRPC_LB_POLICY_WEAK_REF(p, r) \
+  grpc_lb_policy_weak_ref((p), __FILE__, __LINE__, (r))
+#define GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, p, r) \
+  grpc_lb_policy_weak_unref((exec_ctx), (p), __FILE__, __LINE__, (r))
 void grpc_lb_policy_ref(grpc_lb_policy *policy, const char *file, int line,
                         const char *reason);
 void grpc_lb_policy_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
                           const char *file, int line, const char *reason);
+void grpc_lb_policy_weak_ref(grpc_lb_policy *policy, const char *file, int line,
+                             const char *reason);
+void grpc_lb_policy_weak_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+                               const char *file, int line, const char *reason);
 #else
 #define GRPC_LB_POLICY_REF(p, r) grpc_lb_policy_ref((p))
 #define GRPC_LB_POLICY_UNREF(cl, p, r) grpc_lb_policy_unref((cl), (p))
+#define GRPC_LB_POLICY_WEAK_REF(p, r) grpc_lb_policy_weak_ref((p))
+#define GRPC_LB_POLICY_WEAK_UNREF(cl, p, r) grpc_lb_policy_weak_unref((cl), (p))
 void grpc_lb_policy_ref(grpc_lb_policy *policy);
 void grpc_lb_policy_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy);
+void grpc_lb_policy_weak_ref(grpc_lb_policy *policy);
+void grpc_lb_policy_weak_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy);
 #endif
 
 /** called by concrete implementations to initialize the base struct */
 void grpc_lb_policy_init(grpc_lb_policy *policy,
                          const grpc_lb_policy_vtable *vtable);
 
-/** Start shutting down (fail any pending picks) */
-void grpc_lb_policy_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy);
-
 /** Given initial metadata in \a initial_metadata, find an appropriate
     target for this rpc, and 'return' it by calling \a on_complete after setting
     \a target.
@@ -111,13 +121,14 @@ void grpc_lb_policy_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy);
 int grpc_lb_policy_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
                         grpc_pollset *pollset,
                         grpc_metadata_batch *initial_metadata,
-                        grpc_subchannel **target, grpc_closure *on_complete);
+                        grpc_connected_subchannel **target,
+                        grpc_closure *on_complete);
 
-void grpc_lb_policy_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
-                                grpc_subchannel **target);
+void grpc_lb_policy_ping_one(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+                             grpc_closure *closure);
 
-void grpc_lb_policy_broadcast(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
-                              grpc_transport_op *op);
+void grpc_lb_policy_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+                                grpc_connected_subchannel **target);
 
 void grpc_lb_policy_exit_idle(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy);
 

src/core/client_config/resolver.c

@@ -71,11 +71,8 @@ void grpc_resolver_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver) {
 }
 
 void grpc_resolver_channel_saw_error(grpc_exec_ctx *exec_ctx,
-                                     grpc_resolver *resolver,
-                                     struct sockaddr *failing_address,
-                                     int failing_address_len) {
-  resolver->vtable->channel_saw_error(exec_ctx, resolver, failing_address,
-                                      failing_address_len);
+                                     grpc_resolver *resolver) {
+  resolver->vtable->channel_saw_error(exec_ctx, resolver);
 }
 
 void grpc_resolver_next(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,

src/core/client_config/resolver.h

@@ -35,8 +35,8 @@
 #define GRPC_INTERNAL_CORE_CLIENT_CONFIG_RESOLVER_H
 
 #include "src/core/client_config/client_config.h"
+#include "src/core/client_config/subchannel.h"
 #include "src/core/iomgr/iomgr.h"
-#include "src/core/iomgr/sockaddr.h"
 
 typedef struct grpc_resolver grpc_resolver;
 typedef struct grpc_resolver_vtable grpc_resolver_vtable;
@@ -51,9 +51,7 @@ struct grpc_resolver {
 struct grpc_resolver_vtable {
   void (*destroy)(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver);
   void (*shutdown)(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver);
-  void (*channel_saw_error)(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,
-                            struct sockaddr *failing_address,
-                            int failing_address_len);
+  void (*channel_saw_error)(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver);
   void (*next)(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,
                grpc_client_config **target_config, grpc_closure *on_complete);
 };
@@ -81,9 +79,7 @@ void grpc_resolver_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver);
 /** Notification that the channel has seen an error on some address.
     Can be used as a hint that re-resolution is desirable soon. */
 void grpc_resolver_channel_saw_error(grpc_exec_ctx *exec_ctx,
-                                     grpc_resolver *resolver,
-                                     struct sockaddr *failing_address,
-                                     int failing_address_len);
+                                     grpc_resolver *resolver);
 
 /** Get the next client config. Called by the channel to fetch a new
     configuration. Expected to set *target_config with a new configuration,

src/core/client_config/resolvers/dns_resolver.c

@@ -40,7 +40,6 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/client_config/lb_policy_registry.h"
-#include "src/core/client_config/subchannel_factory_decorators/add_channel_arg.h"
 #include "src/core/iomgr/resolve_address.h"
 #include "src/core/support/string.h"
 
@@ -81,9 +80,7 @@ static void dns_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
                                          dns_resolver *r);
 
 static void dns_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *r);
-static void dns_channel_saw_error(grpc_exec_ctx *exec_ctx, grpc_resolver *r,
-                                  struct sockaddr *failing_address,
-                                  int failing_address_len);
+static void dns_channel_saw_error(grpc_exec_ctx *exec_ctx, grpc_resolver *r);
 static void dns_next(grpc_exec_ctx *exec_ctx, grpc_resolver *r,
                      grpc_client_config **target_config,
                      grpc_closure *on_complete);
@@ -103,8 +100,7 @@ static void dns_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver) {
 }
 
 static void dns_channel_saw_error(grpc_exec_ctx *exec_ctx,
-                                  grpc_resolver *resolver, struct sockaddr *sa,
-                                  int len) {
+                                  grpc_resolver *resolver) {
   dns_resolver *r = (dns_resolver *)resolver;
   gpr_mu_lock(&r->mu);
   if (!r->resolving) {

src/core/client_config/resolvers/sockaddr_resolver.c

@@ -83,9 +83,7 @@ static void sockaddr_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
 
 static void sockaddr_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *r);
 static void sockaddr_channel_saw_error(grpc_exec_ctx *exec_ctx,
-                                       grpc_resolver *r,
-                                       struct sockaddr *failing_address,
-                                       int failing_address_len);
+                                       grpc_resolver *r);
 static void sockaddr_next(grpc_exec_ctx *exec_ctx, grpc_resolver *r,
                           grpc_client_config **target_config,
                           grpc_closure *on_complete);
@@ -107,8 +105,13 @@ static void sockaddr_shutdown(grpc_exec_ctx *exec_ctx,
 }
 
 static void sockaddr_channel_saw_error(grpc_exec_ctx *exec_ctx,
-                                       grpc_resolver *resolver,
-                                       struct sockaddr *sa, int len) {}
+                                       grpc_resolver *resolver) {
+  sockaddr_resolver *r = (sockaddr_resolver *)resolver;
+  gpr_mu_lock(&r->mu);
+  r->published = 0;
+  sockaddr_maybe_finish_next_locked(exec_ctx, r);
+  gpr_mu_unlock(&r->mu);
+}
 
 static void sockaddr_next(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,
                           grpc_client_config **target_config,
@@ -344,6 +347,9 @@ static grpc_resolver *sockaddr_create(
   gpr_slice_buffer_destroy(&path_parts);
   gpr_slice_unref(path_slice);
   if (errors_found) {
+    gpr_free(r->lb_policy_name);
+    gpr_free(r->addrs);
+    gpr_free(r->addrs_len);
     gpr_free(r);
     return NULL;
   }

src/core/client_config/resolvers/zookeeper_resolver.c

@@ -96,9 +96,7 @@ static void zookeeper_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
 
 static void zookeeper_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *r);
 static void zookeeper_channel_saw_error(grpc_exec_ctx *exec_ctx,
-                                        grpc_resolver *r,
-                                        struct sockaddr *failing_address,
-                                        int failing_address_len);
+                                        grpc_resolver *r);
 static void zookeeper_next(grpc_exec_ctx *exec_ctx, grpc_resolver *r,
                            grpc_client_config **target_config,
                            grpc_closure *on_complete);
@@ -125,8 +123,7 @@ static void zookeeper_shutdown(grpc_exec_ctx *exec_ctx,
 }
 
 static void zookeeper_channel_saw_error(grpc_exec_ctx *exec_ctx,
-                                        grpc_resolver *resolver,
-                                        struct sockaddr *sa, int len) {
+                                        grpc_resolver *resolver) {
   zookeeper_resolver *r = (zookeeper_resolver *)resolver;
   gpr_mu_lock(&r->mu);
   if (r->resolving == 0) {

src/core/client_config/subchannel.c

@@ -47,39 +47,44 @@
 #include "src/core/transport/connectivity_state.h"
 #include "src/core/transport/connectivity_state.h"
 
+#define INTERNAL_REF_BITS 16
+#define STRONG_REF_MASK (~(gpr_atm)((1 << INTERNAL_REF_BITS) - 1))
+
 #define GRPC_SUBCHANNEL_MIN_CONNECT_TIMEOUT_SECONDS 20
 #define GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS 1
 #define GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER 1.6
 #define GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS 120
 #define GRPC_SUBCHANNEL_RECONNECT_JITTER 0.2
 
-typedef struct {
-  /* all fields protected by subchannel->mu */
-  /** refcount */
-  int refs;
-  /** parent subchannel */
-  grpc_subchannel *subchannel;
-} connection;
+#define GET_CONNECTED_SUBCHANNEL(subchannel, barrier)      \
+  ((grpc_connected_subchannel *)(gpr_atm_##barrier##_load( \
+      &(subchannel)->connected_subchannel)))
 
 typedef struct {
   grpc_closure closure;
-  size_t version;
   grpc_subchannel *subchannel;
   grpc_connectivity_state connectivity_state;
 } state_watcher;
 
-typedef struct waiting_for_connect {
-  struct waiting_for_connect *next;
-  grpc_closure *notify;
-  grpc_pollset *pollset;
-  gpr_atm *target;
+typedef struct external_state_watcher {
   grpc_subchannel *subchannel;
-  grpc_closure continuation;
-} waiting_for_connect;
+  grpc_pollset_set *pollset_set;
+  grpc_closure *notify;
+  grpc_closure closure;
+  struct external_state_watcher *next;
+  struct external_state_watcher *prev;
+} external_state_watcher;
 
 struct grpc_subchannel {
   grpc_connector *connector;
 
+  /** refcount
+      - lower INTERNAL_REF_BITS bits are for internal references:
+        these do not keep the subchannel open.
+      - upper remaining bits are for public references: these do
+        keep the subchannel open */
+  gpr_atm ref_pair;
+
   /** non-transport related channel filters */
   const grpc_channel_filter **filters;
   size_t num_filters;
@@ -88,17 +93,9 @@ struct grpc_subchannel {
   /** address to connect to */
   struct sockaddr *addr;
   size_t addr_len;
+
   /** initial string to send to peer */
   gpr_slice initial_connect_string;
-  /** metadata context */
-  grpc_mdctx *mdctx;
-  /** master channel - the grpc_channel instance that ultimately owns
-      this channel_data via its channel stack.
-      We occasionally use this to bump the refcount on the master channel
-      to keep ourselves alive through an asynchronous operation. */
-  grpc_channel *master;
-  /** have we seen a disconnection? */
-  int disconnected;
 
   /** set during connection */
   grpc_connect_out_args connecting_result;
@@ -107,27 +104,24 @@ struct grpc_subchannel {
   grpc_closure connected;
 
   /** pollset_set tracking who's interested in a connection
-      being setup - owned by the master channel (in particular the
-     client_channel
-      filter there-in) */
-  grpc_pollset_set *pollset_set;
+      being setup */
+  grpc_pollset_set pollset_set;
+
+  /** active connection, or null; of type grpc_connected_subchannel */
+  gpr_atm connected_subchannel;
 
   /** mutex protecting remaining elements */
   gpr_mu mu;
 
-  /** active connection */
-  connection *active;
-  /** version number for the active connection */
-  size_t active_version;
-  /** refcount */
-  int refs;
+  /** have we seen a disconnection? */
+  int disconnected;
   /** are we connecting */
   int connecting;
-  /** things waiting for a connection */
-  waiting_for_connect *waiting;
   /** connectivity state tracking */
   grpc_connectivity_state_tracker state_tracker;
 
+  external_state_watcher root_external_state_watcher;
+
   /** next connect attempt time */
   gpr_timespec next_attempt;
   /** amount to backoff each failure */
@@ -141,152 +135,141 @@ struct grpc_subchannel {
 };
 
 struct grpc_subchannel_call {
-  connection *connection;
+  grpc_connected_subchannel *connection;
 };
 
 #define SUBCHANNEL_CALL_TO_CALL_STACK(call) ((grpc_call_stack *)((call) + 1))
-#define CHANNEL_STACK_FROM_CONNECTION(con) ((grpc_channel_stack *)((con) + 1))
+#define CHANNEL_STACK_FROM_CONNECTION(con) ((grpc_channel_stack *)(con))
 #define CALLSTACK_TO_SUBCHANNEL_CALL(callstack) \
   (((grpc_subchannel_call *)(callstack)) - 1)
 
-static grpc_subchannel_call *create_call(grpc_exec_ctx *exec_ctx,
-                                         connection *con,
-                                         grpc_pollset *pollset);
-static void connectivity_state_changed_locked(grpc_exec_ctx *exec_ctx,
-                                              grpc_subchannel *c,
-                                              const char *reason);
-static grpc_connectivity_state compute_connectivity_locked(grpc_subchannel *c);
 static gpr_timespec compute_connect_deadline(grpc_subchannel *c);
 static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *subchannel,
                                  int iomgr_success);
 
-static void subchannel_ref_locked(grpc_subchannel *c
-                                      GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
-static int subchannel_unref_locked(
-    grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) GRPC_MUST_USE_RESULT;
-static void connection_ref_locked(connection *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
-static grpc_subchannel *connection_unref_locked(
-    grpc_exec_ctx *exec_ctx,
-    connection *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) GRPC_MUST_USE_RESULT;
-static void subchannel_destroy(grpc_exec_ctx *exec_ctx, grpc_subchannel *c);
-
 #ifdef GRPC_STREAM_REFCOUNT_DEBUG
-#define SUBCHANNEL_REF_LOCKED(p, r) \
-  subchannel_ref_locked((p), __FILE__, __LINE__, (r))
-#define SUBCHANNEL_UNREF_LOCKED(p, r) \
-  subchannel_unref_locked((p), __FILE__, __LINE__, (r))
-#define CONNECTION_REF_LOCKED(p, r) \
-  connection_ref_locked((p), __FILE__, __LINE__, (r))
-#define CONNECTION_UNREF_LOCKED(cl, p, r) \
-  connection_unref_locked((cl), (p), __FILE__, __LINE__, (r))
-#define REF_PASS_ARGS , file, line, reason
-#define REF_PASS_REASON , reason
+#define REF_REASON reason
 #define REF_LOG(name, p)                                                  \
   gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "%s: %p   ref %d -> %d %s", \
-          (name), (p), (p)->refs, (p)->refs + 1, reason)
+          (name), (p), (p)->refs.count, (p)->refs.count + 1, reason)
 #define UNREF_LOG(name, p)                                                \
   gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "%s: %p unref %d -> %d %s", \
-          (name), (p), (p)->refs, (p)->refs - 1, reason)
+          (name), (p), (p)->refs.count, (p)->refs.count - 1, reason)
+#define REF_MUTATE_EXTRA_ARGS \
+  GRPC_SUBCHANNEL_REF_EXTRA_ARGS, const char *purpose
+#define REF_MUTATE_PURPOSE(x) , file, line, reason, x
 #else
-#define SUBCHANNEL_REF_LOCKED(p, r) subchannel_ref_locked((p))
-#define SUBCHANNEL_UNREF_LOCKED(p, r) subchannel_unref_locked((p))
-#define CONNECTION_REF_LOCKED(p, r) connection_ref_locked((p))
-#define CONNECTION_UNREF_LOCKED(cl, p, r) connection_unref_locked((cl), (p))
-#define REF_PASS_ARGS
-#define REF_PASS_REASON
+#define REF_REASON ""
 #define REF_LOG(name, p) \
   do {                   \
   } while (0)
 #define UNREF_LOG(name, p) \
   do {                     \
   } while (0)
+#define REF_MUTATE_EXTRA_ARGS
+#define REF_MUTATE_PURPOSE(x)
 #endif
 
 /*
  * connection implementation
  */
 
-static void connection_destroy(grpc_exec_ctx *exec_ctx, connection *c) {
-  GPR_ASSERT(c->refs == 0);
+static void connection_destroy(grpc_exec_ctx *exec_ctx, void *arg,
+                               int success) {
+  grpc_connected_subchannel *c = arg;
   grpc_channel_stack_destroy(exec_ctx, CHANNEL_STACK_FROM_CONNECTION(c));
   gpr_free(c);
 }
 
-static void connection_ref_locked(connection *c
-                                      GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-  REF_LOG("CONNECTION", c);
-  subchannel_ref_locked(c->subchannel REF_PASS_ARGS);
-  ++c->refs;
+void grpc_connected_subchannel_ref(grpc_connected_subchannel *c
+                                       GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
+  GRPC_CHANNEL_STACK_REF(CHANNEL_STACK_FROM_CONNECTION(c), REF_REASON);
 }
 
-static grpc_subchannel *connection_unref_locked(
-    grpc_exec_ctx *exec_ctx, connection *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-  grpc_subchannel *destroy = NULL;
-  UNREF_LOG("CONNECTION", c);
-  if (subchannel_unref_locked(c->subchannel REF_PASS_ARGS)) {
-    destroy = c->subchannel;
-  }
-  if (--c->refs == 0 && c->subchannel->active != c) {
-    connection_destroy(exec_ctx, c);
-  }
-  return destroy;
+void grpc_connected_subchannel_unref(grpc_exec_ctx *exec_ctx,
+                                     grpc_connected_subchannel *c
+                                         GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
+  GRPC_CHANNEL_STACK_UNREF(exec_ctx, CHANNEL_STACK_FROM_CONNECTION(c),
+                           REF_REASON);
 }
 
 /*
  * grpc_subchannel implementation
  */
 
-static void subchannel_ref_locked(grpc_subchannel *c
-                                      GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-  REF_LOG("SUBCHANNEL", c);
-  ++c->refs;
+static void subchannel_destroy(grpc_exec_ctx *exec_ctx, void *arg,
+                               int success) {
+  grpc_subchannel *c = arg;
+  gpr_free((void *)c->filters);
+  grpc_channel_args_destroy(c->args);
+  gpr_free(c->addr);
+  gpr_slice_unref(c->initial_connect_string);
+  grpc_connectivity_state_destroy(exec_ctx, &c->state_tracker);
+  grpc_connector_unref(exec_ctx, c->connector);
+  grpc_pollset_set_destroy(&c->pollset_set);
+  gpr_free(c);
 }
 
-static int subchannel_unref_locked(grpc_subchannel *c
-                                       GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-  UNREF_LOG("SUBCHANNEL", c);
-  return --c->refs == 0;
+static gpr_atm ref_mutate(grpc_subchannel *c, gpr_atm delta,
+                          int barrier REF_MUTATE_EXTRA_ARGS) {
+  gpr_atm old_val = barrier ? gpr_atm_full_fetch_add(&c->ref_pair, delta)
+                            : gpr_atm_no_barrier_fetch_add(&c->ref_pair, delta);
+#ifdef GRPC_STREAM_REFCOUNT_DEBUG
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+          "SUBCHANNEL: %p % 12s 0x%08x -> 0x%08x [%s]", c, purpose, old_val,
+          old_val + delta, reason);
+#endif
+  return old_val;
 }
 
 void grpc_subchannel_ref(grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-  gpr_mu_lock(&c->mu);
-  subchannel_ref_locked(c REF_PASS_ARGS);
-  gpr_mu_unlock(&c->mu);
+  gpr_atm old_refs;
+  old_refs = ref_mutate(c, (1 << INTERNAL_REF_BITS),
+                        0 REF_MUTATE_PURPOSE("STRONG_REF"));
+  GPR_ASSERT((old_refs & STRONG_REF_MASK) != 0);
 }
 
-void grpc_subchannel_unref(grpc_exec_ctx *exec_ctx,
-                           grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-  int destroy;
-  gpr_mu_lock(&c->mu);
-  destroy = subchannel_unref_locked(c REF_PASS_ARGS);
-  gpr_mu_unlock(&c->mu);
-  if (destroy) subchannel_destroy(exec_ctx, c);
+void grpc_subchannel_weak_ref(grpc_subchannel *c
+                                  GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
+  gpr_atm old_refs;
+  old_refs = ref_mutate(c, 1, 0 REF_MUTATE_PURPOSE("WEAK_REF"));
+  GPR_ASSERT(old_refs != 0);
 }
 
-static void subchannel_destroy(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
-  if (c->active != NULL) {
-    connection_destroy(exec_ctx, c->active);
+static void disconnect(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
+  grpc_connected_subchannel *con;
+  gpr_mu_lock(&c->mu);
+  GPR_ASSERT(!c->disconnected);
+  c->disconnected = 1;
+  grpc_connector_shutdown(exec_ctx, c->connector);
+  con = GET_CONNECTED_SUBCHANNEL(c, no_barrier);
+  if (con != NULL) {
+    GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, con, "connection");
+    gpr_atm_no_barrier_store(&c->connected_subchannel, 0xdeadbeef);
   }
-  gpr_free((void *)c->filters);
-  grpc_channel_args_destroy(c->args);
-  gpr_free(c->addr);
-  gpr_slice_unref(c->initial_connect_string);
-  grpc_mdctx_unref(c->mdctx);
-  grpc_connectivity_state_destroy(exec_ctx, &c->state_tracker);
-  grpc_connector_unref(exec_ctx, c->connector);
-  gpr_free(c);
+  gpr_mu_unlock(&c->mu);
 }
 
-void grpc_subchannel_add_interested_party(grpc_exec_ctx *exec_ctx,
-                                          grpc_subchannel *c,
-                                          grpc_pollset *pollset) {
-  grpc_pollset_set_add_pollset(exec_ctx, c->pollset_set, pollset);
+void grpc_subchannel_unref(grpc_exec_ctx *exec_ctx,
+                           grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
+  gpr_atm old_refs;
+  old_refs = ref_mutate(c, (gpr_atm)1 - (gpr_atm)(1 << INTERNAL_REF_BITS),
+                        1 REF_MUTATE_PURPOSE("STRONG_UNREF"));
+  if ((old_refs & STRONG_REF_MASK) == (1 << INTERNAL_REF_BITS)) {
+    disconnect(exec_ctx, c);
+  }
+  GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "strong-unref");
 }
 
-void grpc_subchannel_del_interested_party(grpc_exec_ctx *exec_ctx,
-                                          grpc_subchannel *c,
-                                          grpc_pollset *pollset) {
-  grpc_pollset_set_del_pollset(exec_ctx, c->pollset_set, pollset);
+void grpc_subchannel_weak_unref(grpc_exec_ctx *exec_ctx,
+                                grpc_subchannel *c
+                                    GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
+  gpr_atm old_refs;
+  old_refs = ref_mutate(c, -(gpr_atm)1, 1 REF_MUTATE_PURPOSE("WEAK_UNREF"));
+  if (old_refs == 1) {
+    grpc_exec_ctx_enqueue(exec_ctx, grpc_closure_create(subchannel_destroy, c),
+                          1);
+  }
 }
 
 static gpr_uint32 random_seed() {
@@ -296,10 +279,8 @@ static gpr_uint32 random_seed() {
 grpc_subchannel *grpc_subchannel_create(grpc_connector *connector,
                                         grpc_subchannel_args *args) {
   grpc_subchannel *c = gpr_malloc(sizeof(*c));
-  grpc_channel_element *parent_elem = grpc_channel_stack_last_element(
-      grpc_channel_get_channel_stack(args->master));
   memset(c, 0, sizeof(*c));
-  c->refs = 1;
+  gpr_atm_no_barrier_store(&c->ref_pair, 1 << INTERNAL_REF_BITS);
   c->connector = connector;
   grpc_connector_ref(c->connector);
   c->num_filters = args->filter_count;
@@ -308,15 +289,14 @@ grpc_subchannel *grpc_subchannel_create(grpc_connector *connector,
          sizeof(grpc_channel_filter *) * c->num_filters);
   c->addr = gpr_malloc(args->addr_len);
   memcpy(c->addr, args->addr, args->addr_len);
+  grpc_pollset_set_init(&c->pollset_set);
   c->addr_len = args->addr_len;
   grpc_set_initial_connect_string(&c->addr, &c->addr_len,
                                   &c->initial_connect_string);
   c->args = grpc_channel_args_copy(args->args);
-  c->mdctx = args->mdctx;
-  c->master = args->master;
-  c->pollset_set = grpc_client_channel_get_connecting_pollset_set(parent_elem);
   c->random = random_seed();
-  grpc_mdctx_ref(c->mdctx);
+  c->root_external_state_watcher.next = c->root_external_state_watcher.prev =
+      &c->root_external_state_watcher;
   grpc_closure_init(&c->connected, subchannel_connected, c);
   grpc_connectivity_state_init(&c->state_tracker, GRPC_CHANNEL_IDLE,
                                "subchannel");
@@ -324,70 +304,18 @@ grpc_subchannel *grpc_subchannel_create(grpc_connector *connector,
   return c;
 }
 
-static void cancel_waiting_calls(grpc_exec_ctx *exec_ctx,
-                                 grpc_subchannel *subchannel,
-                                 int iomgr_success) {
-  waiting_for_connect *w4c;
-  gpr_mu_lock(&subchannel->mu);
-  w4c = subchannel->waiting;
-  subchannel->waiting = NULL;
-  gpr_mu_unlock(&subchannel->mu);
-  while (w4c != NULL) {
-    waiting_for_connect *next = w4c->next;
-    grpc_subchannel_del_interested_party(exec_ctx, w4c->subchannel,
-                                         w4c->pollset);
-    if (w4c->notify) {
-      w4c->notify->cb(exec_ctx, w4c->notify->cb_arg, iomgr_success);
-    }
-
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, w4c->subchannel, "waiting_for_connect");
-    gpr_free(w4c);
-
-    w4c = next;
-  }
-}
-
-void grpc_subchannel_cancel_create_call(grpc_exec_ctx *exec_ctx,
-                                        grpc_subchannel *subchannel,
-                                        gpr_atm *target) {
-  waiting_for_connect *w4c;
-  int unref_count = 0;
-  gpr_mu_lock(&subchannel->mu);
-  w4c = subchannel->waiting;
-  subchannel->waiting = NULL;
-  while (w4c != NULL) {
-    waiting_for_connect *next = w4c->next;
-    if (w4c->target == target) {
-      grpc_subchannel_del_interested_party(exec_ctx, w4c->subchannel,
-                                           w4c->pollset);
-      grpc_exec_ctx_enqueue(exec_ctx, w4c->notify, 0);
-
-      unref_count++;
-      gpr_free(w4c);
-    } else {
-      w4c->next = subchannel->waiting;
-      subchannel->waiting = w4c;
-    }
-
-    w4c = next;
-  }
-  gpr_mu_unlock(&subchannel->mu);
-
-  while (unref_count-- > 0) {
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, subchannel, "waiting_for_connect");
-  }
-}
-
 static void continue_connect(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
   grpc_connect_in_args args;
 
-  args.interested_parties = c->pollset_set;
+  args.interested_parties = &c->pollset_set;
   args.addr = c->addr;
   args.addr_len = c->addr_len;
   args.deadline = compute_connect_deadline(c);
   args.channel_args = c->args;
   args.initial_connect_string = c->initial_connect_string;
 
+  grpc_connectivity_state_set(exec_ctx, &c->state_tracker,
+                              GRPC_CHANNEL_CONNECTING, "state_change");
   grpc_connector_connect(exec_ctx, c->connector, &args, &c->connecting_result,
                          &c->connected);
 }
@@ -400,66 +328,6 @@ static void start_connect(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
   continue_connect(exec_ctx, c);
 }
 
-static void continue_creating_call(grpc_exec_ctx *exec_ctx, void *arg,
-                                   int iomgr_success) {
-  int call_creation_finished_ok;
-  waiting_for_connect *w4c = arg;
-  grpc_subchannel_del_interested_party(exec_ctx, w4c->subchannel, w4c->pollset);
-  call_creation_finished_ok = grpc_subchannel_create_call(
-      exec_ctx, w4c->subchannel, w4c->pollset, w4c->target, w4c->notify);
-  GPR_ASSERT(call_creation_finished_ok == 1);
-  w4c->notify->cb(exec_ctx, w4c->notify->cb_arg, iomgr_success);
-  GRPC_SUBCHANNEL_UNREF(exec_ctx, w4c->subchannel, "waiting_for_connect");
-  gpr_free(w4c);
-}
-
-int grpc_subchannel_create_call(grpc_exec_ctx *exec_ctx, grpc_subchannel *c,
-                                grpc_pollset *pollset, gpr_atm *target,
-                                grpc_closure *notify) {
-  connection *con;
-  grpc_subchannel_call *call;
-  GPR_TIMER_BEGIN("grpc_subchannel_create_call", 0);
-  gpr_mu_lock(&c->mu);
-  if (c->active != NULL) {
-    con = c->active;
-    CONNECTION_REF_LOCKED(con, "call");
-    gpr_mu_unlock(&c->mu);
-
-    call = create_call(exec_ctx, con, pollset);
-    if (!gpr_atm_rel_cas(target, 0, (gpr_atm)(gpr_uintptr)call)) {
-      GRPC_SUBCHANNEL_CALL_UNREF(exec_ctx, call, "failed to set");
-    }
-    GPR_TIMER_END("grpc_subchannel_create_call", 0);
-    return 1;
-  } else {
-    waiting_for_connect *w4c = gpr_malloc(sizeof(*w4c));
-    w4c->next = c->waiting;
-    w4c->notify = notify;
-    w4c->pollset = pollset;
-    w4c->target = target;
-    w4c->subchannel = c;
-    /* released when clearing w4c */
-    SUBCHANNEL_REF_LOCKED(c, "waiting_for_connect");
-    grpc_closure_init(&w4c->continuation, continue_creating_call, w4c);
-    c->waiting = w4c;
-    grpc_subchannel_add_interested_party(exec_ctx, c, pollset);
-    if (!c->connecting) {
-      c->connecting = 1;
-      connectivity_state_changed_locked(exec_ctx, c, "create_call");
-      /* released by connection */
-      SUBCHANNEL_REF_LOCKED(c, "connecting");
-      GRPC_CHANNEL_INTERNAL_REF(c->master, "connecting");
-      gpr_mu_unlock(&c->mu);
-
-      start_connect(exec_ctx, c);
-    } else {
-      gpr_mu_unlock(&c->mu);
-    }
-    GPR_TIMER_END("grpc_subchannel_create_call", 0);
-    return 0;
-  }
-}
-
 grpc_connectivity_state grpc_subchannel_check_connectivity(grpc_subchannel *c) {
   grpc_connectivity_state state;
   gpr_mu_lock(&c->mu);
@@ -468,153 +336,149 @@ grpc_connectivity_state grpc_subchannel_check_connectivity(grpc_subchannel *c) {
   return state;
 }
 
-void grpc_subchannel_notify_on_state_change(grpc_exec_ctx *exec_ctx,
-                                            grpc_subchannel *c,
-                                            grpc_connectivity_state *state,
-                                            grpc_closure *notify) {
+static void on_external_state_watcher_done(grpc_exec_ctx *exec_ctx, void *arg,
+                                           int success) {
+  external_state_watcher *w = arg;
+  grpc_closure *follow_up = w->notify;
+  if (w->pollset_set != NULL) {
+    grpc_pollset_set_del_pollset_set(exec_ctx, &w->subchannel->pollset_set,
+                                     w->pollset_set);
+  }
+  gpr_mu_lock(&w->subchannel->mu);
+  w->next->prev = w->prev;
+  w->prev->next = w->next;
+  gpr_mu_unlock(&w->subchannel->mu);
+  GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, w->subchannel, "external_state_watcher");
+  gpr_free(w);
+  follow_up->cb(exec_ctx, follow_up->cb_arg, success);
+}
+
+void grpc_subchannel_notify_on_state_change(
+    grpc_exec_ctx *exec_ctx, grpc_subchannel *c,
+    grpc_pollset_set *interested_parties, grpc_connectivity_state *state,
+    grpc_closure *notify) {
   int do_connect = 0;
-  gpr_mu_lock(&c->mu);
-  if (grpc_connectivity_state_notify_on_state_change(
-          exec_ctx, &c->state_tracker, state, notify)) {
-    do_connect = 1;
-    c->connecting = 1;
-    /* released by connection */
-    SUBCHANNEL_REF_LOCKED(c, "connecting");
-    GRPC_CHANNEL_INTERNAL_REF(c->master, "connecting");
-    connectivity_state_changed_locked(exec_ctx, c, "state_change");
+  external_state_watcher *w;
+
+  if (state == NULL) {
+    gpr_mu_lock(&c->mu);
+    for (w = c->root_external_state_watcher.next;
+         w != &c->root_external_state_watcher; w = w->next) {
+      if (w->notify == notify) {
+        grpc_connectivity_state_notify_on_state_change(
+            exec_ctx, &c->state_tracker, NULL, &w->closure);
+      }
+    }
+    gpr_mu_unlock(&c->mu);
+  } else {
+    w = gpr_malloc(sizeof(*w));
+    w->subchannel = c;
+    w->pollset_set = interested_parties;
+    w->notify = notify;
+    grpc_closure_init(&w->closure, on_external_state_watcher_done, w);
+    if (interested_parties != NULL) {
+      grpc_pollset_set_add_pollset_set(exec_ctx, &c->pollset_set,
+                                       interested_parties);
+    }
+    GRPC_SUBCHANNEL_WEAK_REF(c, "external_state_watcher");
+    gpr_mu_lock(&c->mu);
+    w->next = &c->root_external_state_watcher;
+    w->prev = w->next->prev;
+    w->next->prev = w->prev->next = w;
+    if (grpc_connectivity_state_notify_on_state_change(
+            exec_ctx, &c->state_tracker, state, &w->closure)) {
+      do_connect = 1;
+      c->connecting = 1;
+      /* released by connection */
+      GRPC_SUBCHANNEL_WEAK_REF(c, "connecting");
+    }
+    gpr_mu_unlock(&c->mu);
   }
-  gpr_mu_unlock(&c->mu);
 
   if (do_connect) {
     start_connect(exec_ctx, c);
   }
 }
 
-int grpc_subchannel_state_change_unsubscribe(grpc_exec_ctx *exec_ctx,
-                                             grpc_subchannel *c,
-                                             grpc_closure *subscribed_notify) {
-  int success;
-  gpr_mu_lock(&c->mu);
-  success = grpc_connectivity_state_change_unsubscribe(
-      exec_ctx, &c->state_tracker, subscribed_notify);
-  gpr_mu_unlock(&c->mu);
-  return success;
+void grpc_connected_subchannel_process_transport_op(
+    grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con,
+    grpc_transport_op *op) {
+  grpc_channel_stack *channel_stack = CHANNEL_STACK_FROM_CONNECTION(con);
+  grpc_channel_element *top_elem = grpc_channel_stack_element(channel_stack, 0);
+  top_elem->filter->start_transport_op(exec_ctx, top_elem, op);
 }
 
-void grpc_subchannel_process_transport_op(grpc_exec_ctx *exec_ctx,
-                                          grpc_subchannel *c,
-                                          grpc_transport_op *op) {
-  connection *con = NULL;
-  grpc_subchannel *destroy;
-  int cancel_alarm = 0;
-  gpr_mu_lock(&c->mu);
-  if (c->active != NULL) {
-    con = c->active;
-    CONNECTION_REF_LOCKED(con, "transport-op");
-  }
-  if (op->disconnect) {
-    c->disconnected = 1;
-    connectivity_state_changed_locked(exec_ctx, c, "disconnect");
-    if (c->have_alarm) {
-      cancel_alarm = 1;
-    }
-  }
-  gpr_mu_unlock(&c->mu);
+static void subchannel_on_child_state_changed(grpc_exec_ctx *exec_ctx, void *p,
+                                              int iomgr_success) {
+  state_watcher *sw = p;
+  grpc_subchannel *c = sw->subchannel;
+  gpr_mu *mu = &c->mu;
 
-  if (con != NULL) {
-    grpc_channel_stack *channel_stack = CHANNEL_STACK_FROM_CONNECTION(con);
-    grpc_channel_element *top_elem =
-        grpc_channel_stack_element(channel_stack, 0);
-    top_elem->filter->start_transport_op(exec_ctx, top_elem, op);
+  gpr_mu_lock(mu);
 
-    gpr_mu_lock(&c->mu);
-    destroy = CONNECTION_UNREF_LOCKED(exec_ctx, con, "transport-op");
-    gpr_mu_unlock(&c->mu);
-    if (destroy) {
-      subchannel_destroy(exec_ctx, destroy);
+  /* if we failed just leave this closure */
+  if (iomgr_success) {
+    if (sw->connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
+      /* any errors on a subchannel ==> we're done, create a new one */
+      sw->connectivity_state = GRPC_CHANNEL_FATAL_FAILURE;
+    }
+    grpc_connectivity_state_set(exec_ctx, &c->state_tracker,
+                                sw->connectivity_state, "reflect_child");
+    if (sw->connectivity_state != GRPC_CHANNEL_FATAL_FAILURE) {
+      grpc_connected_subchannel_notify_on_state_change(
+          exec_ctx, GET_CONNECTED_SUBCHANNEL(c, no_barrier), NULL,
+          &sw->connectivity_state, &sw->closure);
+      GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
+      sw = NULL;
     }
   }
 
-  if (cancel_alarm) {
-    grpc_timer_cancel(exec_ctx, &c->alarm);
-  }
-
-  if (op->disconnect) {
-    grpc_connector_shutdown(exec_ctx, c->connector);
-  }
+  gpr_mu_unlock(mu);
+  GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "state_watcher");
+  gpr_free(sw);
 }
 
-static void on_state_changed(grpc_exec_ctx *exec_ctx, void *p,
-                             int iomgr_success) {
-  state_watcher *sw = p;
-  grpc_subchannel *c = sw->subchannel;
-  gpr_mu *mu = &c->mu;
-  int destroy;
+static void connected_subchannel_state_op(grpc_exec_ctx *exec_ctx,
+                                          grpc_connected_subchannel *con,
+                                          grpc_pollset_set *interested_parties,
+                                          grpc_connectivity_state *state,
+                                          grpc_closure *closure) {
   grpc_transport_op op;
   grpc_channel_element *elem;
-  connection *destroy_connection = NULL;
-
-  gpr_mu_lock(mu);
-
-  /* if we failed or there is a version number mismatch, just leave
-     this closure */
-  if (!iomgr_success || sw->subchannel->active_version != sw->version) {
-    goto done;
-  }
+  memset(&op, 0, sizeof(op));
+  op.connectivity_state = state;
+  op.on_connectivity_state_change = closure;
+  op.bind_pollset_set = interested_parties;
+  elem = grpc_channel_stack_element(CHANNEL_STACK_FROM_CONNECTION(con), 0);
+  elem->filter->start_transport_op(exec_ctx, elem, &op);
+}
 
-  switch (sw->connectivity_state) {
-    case GRPC_CHANNEL_CONNECTING:
-    case GRPC_CHANNEL_READY:
-    case GRPC_CHANNEL_IDLE:
-      /* all is still good: keep watching */
-      memset(&op, 0, sizeof(op));
-      op.connectivity_state = &sw->connectivity_state;
-      op.on_connectivity_state_change = &sw->closure;
-      elem = grpc_channel_stack_element(
-          CHANNEL_STACK_FROM_CONNECTION(c->active), 0);
-      elem->filter->start_transport_op(exec_ctx, elem, &op);
-      /* early out */
-      gpr_mu_unlock(mu);
-      return;
-    case GRPC_CHANNEL_FATAL_FAILURE:
-    case GRPC_CHANNEL_TRANSIENT_FAILURE:
-      /* things have gone wrong, deactivate and enter idle */
-      if (sw->subchannel->active->refs == 0) {
-        destroy_connection = sw->subchannel->active;
-      }
-      sw->subchannel->active = NULL;
-      grpc_connectivity_state_set(exec_ctx, &c->state_tracker,
-                                  c->disconnected
-                                      ? GRPC_CHANNEL_FATAL_FAILURE
-                                      : GRPC_CHANNEL_TRANSIENT_FAILURE,
-                                  "connection_failed");
-      break;
-  }
+void grpc_connected_subchannel_notify_on_state_change(
+    grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con,
+    grpc_pollset_set *interested_parties, grpc_connectivity_state *state,
+    grpc_closure *closure) {
+  connected_subchannel_state_op(exec_ctx, con, interested_parties, state,
+                                closure);
+}
 
-done:
-  connectivity_state_changed_locked(exec_ctx, c, "transport_state_changed");
-  destroy = SUBCHANNEL_UNREF_LOCKED(c, "state_watcher");
-  gpr_free(sw);
-  gpr_mu_unlock(mu);
-  if (destroy) {
-    subchannel_destroy(exec_ctx, c);
-  }
-  if (destroy_connection != NULL) {
-    connection_destroy(exec_ctx, destroy_connection);
-  }
+void grpc_connected_subchannel_ping(grpc_exec_ctx *exec_ctx,
+                                    grpc_connected_subchannel *con,
+                                    grpc_closure *closure) {
+  grpc_transport_op op;
+  grpc_channel_element *elem;
+  memset(&op, 0, sizeof(op));
+  op.send_ping = closure;
+  elem = grpc_channel_stack_element(CHANNEL_STACK_FROM_CONNECTION(con), 0);
+  elem->filter->start_transport_op(exec_ctx, elem, &op);
 }
 
 static void publish_transport(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
   size_t channel_stack_size;
-  connection *con;
+  grpc_connected_subchannel *con;
   grpc_channel_stack *stk;
   size_t num_filters;
   const grpc_channel_filter **filters;
-  waiting_for_connect *w4c;
-  grpc_transport_op op;
-  state_watcher *sw;
-  connection *destroy_connection = NULL;
-  grpc_channel_element *elem;
+  state_watcher *sw_subchannel;
 
   /* build final filter list */
   num_filters = c->num_filters + c->connecting_result.num_filters + 1;
@@ -626,74 +490,53 @@ static void publish_transport(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
 
   /* construct channel stack */
   channel_stack_size = grpc_channel_stack_size(filters, num_filters);
-  con = gpr_malloc(sizeof(connection) + channel_stack_size);
-  stk = (grpc_channel_stack *)(con + 1);
-  con->refs = 0;
-  con->subchannel = c;
-  grpc_channel_stack_init(exec_ctx, filters, num_filters, c->master, c->args,
-                          c->mdctx, stk);
+  con = gpr_malloc(channel_stack_size);
+  stk = CHANNEL_STACK_FROM_CONNECTION(con);
+  grpc_channel_stack_init(exec_ctx, 1, connection_destroy, con, filters,
+                          num_filters, c->connecting_result.channel_args,
+                          "CONNECTED_SUBCHANNEL", stk);
   grpc_connected_channel_bind_transport(stk, c->connecting_result.transport);
   gpr_free((void *)c->connecting_result.filters);
   memset(&c->connecting_result, 0, sizeof(c->connecting_result));
 
   /* initialize state watcher */
-  sw = gpr_malloc(sizeof(*sw));
-  grpc_closure_init(&sw->closure, on_state_changed, sw);
-  sw->subchannel = c;
-  sw->connectivity_state = GRPC_CHANNEL_READY;
+  sw_subchannel = gpr_malloc(sizeof(*sw_subchannel));
+  sw_subchannel->subchannel = c;
+  sw_subchannel->connectivity_state = GRPC_CHANNEL_READY;
+  grpc_closure_init(&sw_subchannel->closure, subchannel_on_child_state_changed,
+                    sw_subchannel);
 
   gpr_mu_lock(&c->mu);
 
   if (c->disconnected) {
     gpr_mu_unlock(&c->mu);
-    gpr_free(sw);
+    gpr_free(sw_subchannel);
     gpr_free((void *)filters);
     grpc_channel_stack_destroy(exec_ctx, stk);
-    GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, c->master, "connecting");
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, c, "connecting");
+    gpr_free(con);
+    GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
     return;
   }
 
   /* publish */
-  if (c->active != NULL && c->active->refs == 0) {
-    destroy_connection = c->active;
-  }
-  c->active = con;
-  c->active_version++;
-  sw->version = c->active_version;
+  GPR_ASSERT(gpr_atm_no_barrier_cas(&c->connected_subchannel, 0, (gpr_atm)con));
   c->connecting = 0;
 
-  /* watch for changes; subchannel ref for connecting is donated
+  /* setup subchannel watching connected subchannel for changes; subchannel ref
+     for connecting is donated
      to the state watcher */
-  memset(&op, 0, sizeof(op));
-  op.connectivity_state = &sw->connectivity_state;
-  op.on_connectivity_state_change = &sw->closure;
-  op.bind_pollset_set = c->pollset_set;
-  SUBCHANNEL_REF_LOCKED(c, "state_watcher");
-  GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, c->master, "connecting");
-  GPR_ASSERT(!SUBCHANNEL_UNREF_LOCKED(c, "connecting"));
-  elem =
-      grpc_channel_stack_element(CHANNEL_STACK_FROM_CONNECTION(c->active), 0);
-  elem->filter->start_transport_op(exec_ctx, elem, &op);
+  GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
+  GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
+  grpc_connected_subchannel_notify_on_state_change(
+      exec_ctx, con, &c->pollset_set, &sw_subchannel->connectivity_state,
+      &sw_subchannel->closure);
 
   /* signal completion */
-  connectivity_state_changed_locked(exec_ctx, c, "connected");
-  w4c = c->waiting;
-  c->waiting = NULL;
+  grpc_connectivity_state_set(exec_ctx, &c->state_tracker, GRPC_CHANNEL_READY,
+                              "connected");
 
   gpr_mu_unlock(&c->mu);
-
-  while (w4c != NULL) {
-    waiting_for_connect *next = w4c->next;
-    grpc_exec_ctx_enqueue(exec_ctx, &w4c->continuation, 1);
-    w4c = next;
-  }
-
   gpr_free((void *)filters);
-
-  if (destroy_connection != NULL) {
-    connection_destroy(exec_ctx, destroy_connection);
-  }
 }
 
 /* Generate a random number between 0 and 1. */
@@ -747,29 +590,31 @@ static void on_alarm(grpc_exec_ctx *exec_ctx, void *arg, int iomgr_success) {
   if (c->disconnected) {
     iomgr_success = 0;
   }
-  connectivity_state_changed_locked(exec_ctx, c, "alarm");
   gpr_mu_unlock(&c->mu);
   if (iomgr_success) {
     update_reconnect_parameters(c);
     continue_connect(exec_ctx, c);
   } else {
-    cancel_waiting_calls(exec_ctx, c, iomgr_success);
-    GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, c->master, "connecting");
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, c, "connecting");
+    GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
   }
 }
 
 static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *arg,
                                  int iomgr_success) {
   grpc_subchannel *c = arg;
+
   if (c->connecting_result.transport != NULL) {
     publish_transport(exec_ctx, c);
+  } else if (c->disconnected) {
+    GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
   } else {
     gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
     gpr_mu_lock(&c->mu);
     GPR_ASSERT(!c->have_alarm);
     c->have_alarm = 1;
-    connectivity_state_changed_locked(exec_ctx, c, "connect_failed");
+    grpc_connectivity_state_set(exec_ctx, &c->state_tracker,
+                                GRPC_CHANNEL_TRANSIENT_FAILURE,
+                                "connect_failed");
     grpc_timer_init(exec_ctx, &c->alarm, c->next_attempt, on_alarm, c, now);
     gpr_mu_unlock(&c->mu);
   }
@@ -786,29 +631,6 @@ static gpr_timespec compute_connect_deadline(grpc_subchannel *c) {
                                                           : min_deadline;
 }
 
-static grpc_connectivity_state compute_connectivity_locked(grpc_subchannel *c) {
-  if (c->disconnected) {
-    return GRPC_CHANNEL_FATAL_FAILURE;
-  }
-  if (c->connecting) {
-    if (c->have_alarm) {
-      return GRPC_CHANNEL_TRANSIENT_FAILURE;
-    }
-    return GRPC_CHANNEL_CONNECTING;
-  }
-  if (c->active) {
-    return GRPC_CHANNEL_READY;
-  }
-  return GRPC_CHANNEL_IDLE;
-}
-
-static void connectivity_state_changed_locked(grpc_exec_ctx *exec_ctx,
-                                              grpc_subchannel *c,
-                                              const char *reason) {
-  grpc_connectivity_state current = compute_connectivity_locked(c);
-  grpc_connectivity_state_set(exec_ctx, &c->state_tracker, current, reason);
-}
-
 /*
  * grpc_subchannel_call implementation
  */
@@ -816,37 +638,22 @@ static void connectivity_state_changed_locked(grpc_exec_ctx *exec_ctx,
 static void subchannel_call_destroy(grpc_exec_ctx *exec_ctx, void *call,
                                     int success) {
   grpc_subchannel_call *c = call;
-  gpr_mu *mu = &c->connection->subchannel->mu;
-  grpc_subchannel *destroy;
   GPR_TIMER_BEGIN("grpc_subchannel_call_unref.destroy", 0);
   grpc_call_stack_destroy(exec_ctx, SUBCHANNEL_CALL_TO_CALL_STACK(c));
-  gpr_mu_lock(mu);
-  destroy = CONNECTION_UNREF_LOCKED(exec_ctx, c->connection, "call");
-  gpr_mu_unlock(mu);
+  GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, c->connection, "subchannel_call");
   gpr_free(c);
-  if (destroy != NULL) {
-    subchannel_destroy(exec_ctx, destroy);
-  }
   GPR_TIMER_END("grpc_subchannel_call_unref.destroy", 0);
 }
 
 void grpc_subchannel_call_ref(grpc_subchannel_call *c
                                   GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-#ifdef GRPC_STREAM_REFCOUNT_DEBUG
-  grpc_call_stack_ref(SUBCHANNEL_CALL_TO_CALL_STACK(c), reason);
-#else
-  grpc_call_stack_ref(SUBCHANNEL_CALL_TO_CALL_STACK(c));
-#endif
+  GRPC_CALL_STACK_REF(SUBCHANNEL_CALL_TO_CALL_STACK(c), REF_REASON);
 }
 
 void grpc_subchannel_call_unref(grpc_exec_ctx *exec_ctx,
                                 grpc_subchannel_call *c
                                     GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-#ifdef GRPC_STREAM_REFCOUNT_DEBUG
-  grpc_call_stack_unref(exec_ctx, SUBCHANNEL_CALL_TO_CALL_STACK(c), reason);
-#else
-  grpc_call_stack_unref(exec_ctx, SUBCHANNEL_CALL_TO_CALL_STACK(c));
-#endif
+  GRPC_CALL_STACK_UNREF(exec_ctx, SUBCHANNEL_CALL_TO_CALL_STACK(c), REF_REASON);
 }
 
 char *grpc_subchannel_call_get_peer(grpc_exec_ctx *exec_ctx,
@@ -864,28 +671,26 @@ void grpc_subchannel_call_process_op(grpc_exec_ctx *exec_ctx,
   top_elem->filter->start_transport_stream_op(exec_ctx, top_elem, op);
 }
 
-static grpc_subchannel_call *create_call(grpc_exec_ctx *exec_ctx,
-                                         connection *con,
-                                         grpc_pollset *pollset) {
+grpc_connected_subchannel *grpc_subchannel_get_connected_subchannel(
+    grpc_subchannel *c) {
+  return GET_CONNECTED_SUBCHANNEL(c, acq);
+}
+
+grpc_subchannel_call *grpc_connected_subchannel_create_call(
+    grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con,
+    grpc_pollset *pollset) {
   grpc_channel_stack *chanstk = CHANNEL_STACK_FROM_CONNECTION(con);
   grpc_subchannel_call *call =
       gpr_malloc(sizeof(grpc_subchannel_call) + chanstk->call_stack_size);
   grpc_call_stack *callstk = SUBCHANNEL_CALL_TO_CALL_STACK(call);
   call->connection = con;
+  GRPC_CONNECTED_SUBCHANNEL_REF(con, "subchannel_call");
   grpc_call_stack_init(exec_ctx, chanstk, 1, subchannel_call_destroy, call,
                        NULL, NULL, callstk);
   grpc_call_stack_set_pollset(exec_ctx, callstk, pollset);
   return call;
 }
 
-grpc_mdctx *grpc_subchannel_get_mdctx(grpc_subchannel *subchannel) {
-  return subchannel->mdctx;
-}
-
-grpc_channel *grpc_subchannel_get_master(grpc_subchannel *subchannel) {
-  return subchannel->master;
-}
-
 grpc_call_stack *grpc_subchannel_call_get_call_stack(
     grpc_subchannel_call *subchannel_call) {
   return SUBCHANNEL_CALL_TO_CALL_STACK(subchannel_call);

src/core/client_config/subchannel.h

@@ -41,6 +41,7 @@
 /** A (sub-)channel that knows how to connect to exactly one target
     address. Provides a target for load balancing. */
 typedef struct grpc_subchannel grpc_subchannel;
+typedef struct grpc_connected_subchannel grpc_connected_subchannel;
 typedef struct grpc_subchannel_call grpc_subchannel_call;
 typedef struct grpc_subchannel_args grpc_subchannel_args;
 
@@ -49,6 +50,14 @@ typedef struct grpc_subchannel_args grpc_subchannel_args;
   grpc_subchannel_ref((p), __FILE__, __LINE__, (r))
 #define GRPC_SUBCHANNEL_UNREF(cl, p, r) \
   grpc_subchannel_unref((cl), (p), __FILE__, __LINE__, (r))
+#define GRPC_SUBCHANNEL_WEAK_REF(p, r) \
+  grpc_subchannel_weak_ref((p), __FILE__, __LINE__, (r))
+#define GRPC_SUBCHANNEL_WEAK_UNREF(cl, p, r) \
+  grpc_subchannel_weak_unref((cl), (p), __FILE__, __LINE__, (r))
+#define GRPC_CONNECTED_SUBCHANNEL_REF(p, r) \
+  grpc_connected_subchannel_ref((p), __FILE__, __LINE__, (r))
+#define GRPC_CONNECTED_SUBCHANNEL_UNREF(cl, p, r) \
+  grpc_connected_subchannel_unref((cl), (p), __FILE__, __LINE__, (r))
 #define GRPC_SUBCHANNEL_CALL_REF(p, r) \
   grpc_subchannel_call_ref((p), __FILE__, __LINE__, (r))
 #define GRPC_SUBCHANNEL_CALL_UNREF(cl, p, r) \
@@ -58,6 +67,12 @@ typedef struct grpc_subchannel_args grpc_subchannel_args;
 #else
 #define GRPC_SUBCHANNEL_REF(p, r) grpc_subchannel_ref((p))
 #define GRPC_SUBCHANNEL_UNREF(cl, p, r) grpc_subchannel_unref((cl), (p))
+#define GRPC_SUBCHANNEL_WEAK_REF(p, r) grpc_subchannel_weak_ref((p))
+#define GRPC_SUBCHANNEL_WEAK_UNREF(cl, p, r) \
+  grpc_subchannel_weak_unref((cl), (p))
+#define GRPC_CONNECTED_SUBCHANNEL_REF(p, r) grpc_connected_subchannel_ref((p))
+#define GRPC_CONNECTED_SUBCHANNEL_UNREF(cl, p, r) \
+  grpc_connected_subchannel_unref((cl), (p))
 #define GRPC_SUBCHANNEL_CALL_REF(p, r) grpc_subchannel_call_ref((p))
 #define GRPC_SUBCHANNEL_CALL_UNREF(cl, p, r) \
   grpc_subchannel_call_unref((cl), (p))
@@ -69,33 +84,31 @@ void grpc_subchannel_ref(grpc_subchannel *channel
 void grpc_subchannel_unref(grpc_exec_ctx *exec_ctx,
                            grpc_subchannel *channel
                                GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
+void grpc_subchannel_weak_ref(grpc_subchannel *channel
+                                  GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
+void grpc_subchannel_weak_unref(grpc_exec_ctx *exec_ctx,
+                                grpc_subchannel *channel
+                                    GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
+void grpc_connected_subchannel_ref(grpc_connected_subchannel *channel
+                                       GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
+void grpc_connected_subchannel_unref(grpc_exec_ctx *exec_ctx,
+                                     grpc_connected_subchannel *channel
+                                         GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
 void grpc_subchannel_call_ref(grpc_subchannel_call *call
                                   GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
 void grpc_subchannel_call_unref(grpc_exec_ctx *exec_ctx,
                                 grpc_subchannel_call *call
                                     GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
 
-/** construct a subchannel call (possibly asynchronously).
- *
- * If the returned status is 1, the call will return immediately and \a target
- * will point to a connected \a subchannel_call instance. Note that \a notify
- * will \em not be invoked in this case.
- * Otherwise, if the returned status is 0, the subchannel call will be created
- * asynchronously, invoking the \a notify callback upon completion. */
-int grpc_subchannel_create_call(grpc_exec_ctx *exec_ctx,
-                                grpc_subchannel *subchannel,
-                                grpc_pollset *pollset, gpr_atm *target,
-                                grpc_closure *notify);
-
-/** cancel \a call in the waiting state. */
-void grpc_subchannel_cancel_create_call(grpc_exec_ctx *exec_ctx,
-                                        grpc_subchannel *subchannel,
-                                        gpr_atm *target);
+/** construct a subchannel call */
+grpc_subchannel_call *grpc_connected_subchannel_create_call(
+    grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *connected_subchannel,
+    grpc_pollset *pollset);
 
 /** process a transport level op */
-void grpc_subchannel_process_transport_op(grpc_exec_ctx *exec_ctx,
-                                          grpc_subchannel *subchannel,
-                                          grpc_transport_op *op);
+void grpc_connected_subchannel_process_transport_op(
+    grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *subchannel,
+    grpc_transport_op *op);
 
 /** poll the current connectivity state of a channel */
 grpc_connectivity_state grpc_subchannel_check_connectivity(
@@ -103,26 +116,22 @@ grpc_connectivity_state grpc_subchannel_check_connectivity(
 
 /** call notify when the connectivity state of a channel changes from *state.
     Updates *state with the new state of the channel */
-void grpc_subchannel_notify_on_state_change(grpc_exec_ctx *exec_ctx,
-                                            grpc_subchannel *channel,
-                                            grpc_connectivity_state *state,
-                                            grpc_closure *notify);
-
-/** Remove \a subscribed_notify from the list of closures to be called on a
- * state change if present, returning 1. Otherwise, nothing is done and return
- * 0. */
-int grpc_subchannel_state_change_unsubscribe(grpc_exec_ctx *exec_ctx,
-                                             grpc_subchannel *channel,
-                                             grpc_closure *subscribed_notify);
-
-/** express interest in \a channel's activities through \a pollset. */
-void grpc_subchannel_add_interested_party(grpc_exec_ctx *exec_ctx,
-                                          grpc_subchannel *channel,
-                                          grpc_pollset *pollset);
-/** stop following \a channel's activity through \a pollset. */
-void grpc_subchannel_del_interested_party(grpc_exec_ctx *exec_ctx,
-                                          grpc_subchannel *channel,
-                                          grpc_pollset *pollset);
+void grpc_subchannel_notify_on_state_change(
+    grpc_exec_ctx *exec_ctx, grpc_subchannel *channel,
+    grpc_pollset_set *interested_parties, grpc_connectivity_state *state,
+    grpc_closure *notify);
+void grpc_connected_subchannel_notify_on_state_change(
+    grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *channel,
+    grpc_pollset_set *interested_parties, grpc_connectivity_state *state,
+    grpc_closure *notify);
+void grpc_connected_subchannel_ping(grpc_exec_ctx *exec_ctx,
+                                    grpc_connected_subchannel *channel,
+                                    grpc_closure *notify);
+
+/** retrieve the grpc_connected_subchannel - or NULL if called before
+    the subchannel becomes connected */
+grpc_connected_subchannel *grpc_subchannel_get_connected_subchannel(
+    grpc_subchannel *subchannel);
 
 /** continue processing a transport op */
 void grpc_subchannel_call_process_op(grpc_exec_ctx *exec_ctx,
@@ -147,20 +156,10 @@ struct grpc_subchannel_args {
   /** Address to connect to */
   struct sockaddr *addr;
   size_t addr_len;
-  /** metadata context to use */
-  grpc_mdctx *mdctx;
-  /** master channel */
-  grpc_channel *master;
 };
 
 /** create a subchannel given a connector */
 grpc_subchannel *grpc_subchannel_create(grpc_connector *connector,
                                         grpc_subchannel_args *args);
 
-/** Return the metadata context associated with the subchannel */
-grpc_mdctx *grpc_subchannel_get_mdctx(grpc_subchannel *subchannel);
-
-/** Return the master channel associated with the subchannel */
-grpc_channel *grpc_subchannel_get_master(grpc_subchannel *subchannel);
-
 #endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_H */

src/core/client_config/subchannel_factory_decorators/merge_channel_args.c

@@ -1,86 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "src/core/client_config/subchannel_factory_decorators/merge_channel_args.h"
-#include <grpc/support/alloc.h>
-#include "src/core/channel/channel_args.h"
-
-typedef struct {
-  grpc_subchannel_factory base;
-  gpr_refcount refs;
-  grpc_subchannel_factory *wrapped;
-  grpc_channel_args *merge_args;
-} merge_args_factory;
-
-static void merge_args_factory_ref(grpc_subchannel_factory *scf) {
-  merge_args_factory *f = (merge_args_factory *)scf;
-  gpr_ref(&f->refs);
-}
-
-static void merge_args_factory_unref(grpc_exec_ctx *exec_ctx,
-                                     grpc_subchannel_factory *scf) {
-  merge_args_factory *f = (merge_args_factory *)scf;
-  if (gpr_unref(&f->refs)) {
-    grpc_subchannel_factory_unref(exec_ctx, f->wrapped);
-    grpc_channel_args_destroy(f->merge_args);
-    gpr_free(f);
-  }
-}
-
-static grpc_subchannel *merge_args_factory_create_subchannel(
-    grpc_exec_ctx *exec_ctx, grpc_subchannel_factory *scf,
-    grpc_subchannel_args *args) {
-  merge_args_factory *f = (merge_args_factory *)scf;
-  grpc_channel_args *final_args =
-      grpc_channel_args_merge(args->args, f->merge_args);
-  grpc_subchannel *s;
-  args->args = final_args;
-  s = grpc_subchannel_factory_create_subchannel(exec_ctx, f->wrapped, args);
-  grpc_channel_args_destroy(final_args);
-  return s;
-}
-
-static const grpc_subchannel_factory_vtable merge_args_factory_vtable = {
-    merge_args_factory_ref, merge_args_factory_unref,
-    merge_args_factory_create_subchannel};
-
-grpc_subchannel_factory *grpc_subchannel_factory_merge_channel_args(
-    grpc_subchannel_factory *input, const grpc_channel_args *args) {
-  merge_args_factory *f = gpr_malloc(sizeof(*f));
-  f->base.vtable = &merge_args_factory_vtable;
-  gpr_ref_init(&f->refs, 1);
-  grpc_subchannel_factory_ref(input);
-  f->wrapped = input;
-  f->merge_args = grpc_channel_args_copy(args);
-  return &f->base;
-}

src/core/client_config/subchannel_factory_decorators/merge_channel_args.h

@@ -1,46 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#ifndef GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_MERGE_CHANNEL_ARGS_H
-#define GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_MERGE_CHANNEL_ARGS_H
-
-#include "src/core/client_config/subchannel_factory.h"
-
-/** Takes a subchannel factory, returns a new one that mutates incoming
-    channel_args by adding a new argument; ownership of input, args is retained
-    by the caller. */
-grpc_subchannel_factory *grpc_subchannel_factory_merge_channel_args(
-    grpc_subchannel_factory *input, const grpc_channel_args *args);
-
-#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_MERGE_CHANNEL_ARGS_H \
-        */

src/core/compression/algorithm.c

@@ -37,7 +37,9 @@
 #include <grpc/compression.h>
 #include <grpc/support/useful.h>
 
+#include "src/core/compression/algorithm_metadata.h"
 #include "src/core/surface/api_trace.h"
+#include "src/core/transport/static_metadata.h"
 
 int grpc_compression_algorithm_parse(const char *name, size_t name_length,
                                      grpc_compression_algorithm *algorithm) {
@@ -72,17 +74,55 @@ int grpc_compression_algorithm_name(grpc_compression_algorithm algorithm,
   switch (algorithm) {
     case GRPC_COMPRESS_NONE:
       *name = "identity";
-      break;
+      return 1;
     case GRPC_COMPRESS_DEFLATE:
       *name = "deflate";
-      break;
+      return 1;
     case GRPC_COMPRESS_GZIP:
       *name = "gzip";
-      break;
-    default:
+      return 1;
+    case GRPC_COMPRESS_ALGORITHMS_COUNT:
       return 0;
   }
-  return 1;
+  return 0;
+}
+
+grpc_compression_algorithm grpc_compression_algorithm_from_mdstr(
+    grpc_mdstr *str) {
+  if (str == GRPC_MDSTR_IDENTITY) return GRPC_COMPRESS_NONE;
+  if (str == GRPC_MDSTR_DEFLATE) return GRPC_COMPRESS_DEFLATE;
+  if (str == GRPC_MDSTR_GZIP) return GRPC_COMPRESS_GZIP;
+  return GRPC_COMPRESS_ALGORITHMS_COUNT;
+}
+
+grpc_mdstr *grpc_compression_algorithm_mdstr(
+    grpc_compression_algorithm algorithm) {
+  switch (algorithm) {
+    case GRPC_COMPRESS_NONE:
+      return GRPC_MDSTR_IDENTITY;
+    case GRPC_COMPRESS_DEFLATE:
+      return GRPC_MDSTR_DEFLATE;
+    case GRPC_COMPRESS_GZIP:
+      return GRPC_MDSTR_GZIP;
+    case GRPC_COMPRESS_ALGORITHMS_COUNT:
+      return NULL;
+  }
+  return NULL;
+}
+
+grpc_mdelem *grpc_compression_encoding_mdelem(
+    grpc_compression_algorithm algorithm) {
+  switch (algorithm) {
+    case GRPC_COMPRESS_NONE:
+      return GRPC_MDELEM_GRPC_ENCODING_IDENTITY;
+    case GRPC_COMPRESS_DEFLATE:
+      return GRPC_MDELEM_GRPC_ENCODING_DEFLATE;
+    case GRPC_COMPRESS_GZIP:
+      return GRPC_MDELEM_GRPC_ENCODING_GZIP;
+    default:
+      break;
+  }
+  return NULL;
 }
 
 /* TODO(dgq): Add the ability to specify parameters to the individual
@@ -99,25 +139,9 @@ grpc_compression_algorithm grpc_compression_algorithm_for_level(
     case GRPC_COMPRESS_LEVEL_HIGH:
       return GRPC_COMPRESS_DEFLATE;
     default:
-      /* we shouldn't be making it here */
-      abort();
-      return GRPC_COMPRESS_NONE;
-  }
-}
-
-grpc_compression_level grpc_compression_level_for_algorithm(
-    grpc_compression_algorithm algorithm) {
-  grpc_compression_level clevel;
-  GRPC_API_TRACE("grpc_compression_level_for_algorithm(algorithm=%d)", 1,
-                 ((int)algorithm));
-  for (clevel = GRPC_COMPRESS_LEVEL_NONE; clevel < GRPC_COMPRESS_LEVEL_COUNT;
-       ++clevel) {
-    if (grpc_compression_algorithm_for_level(clevel) == algorithm) {
-      return clevel;
-    }
+      break;
   }
-  abort();
-  return GRPC_COMPRESS_LEVEL_NONE;
+  GPR_UNREACHABLE_CODE(return GRPC_COMPRESS_NONE);
 }
 
 void grpc_compression_options_init(grpc_compression_options *opts) {

src/core/compression/algorithm_metadata.h

@@ -0,0 +1,53 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CORE_COMPRESSION_ALGORITHM_METADATA_H
+#define GRPC_INTERNAL_CORE_COMPRESSION_ALGORITHM_METADATA_H
+
+#include <grpc/compression.h>
+#include "src/core/transport/metadata.h"
+
+/** Return compression algorithm based metadata value */
+grpc_mdstr *grpc_compression_algorithm_mdstr(
+    grpc_compression_algorithm algorithm);
+
+/** Return compression algorithm based metadata element (grpc-encoding: xxx) */
+grpc_mdelem *grpc_compression_encoding_mdelem(
+    grpc_compression_algorithm algorithm);
+
+/** Find compression algorithm based on passed in mdstr - returns
+ * GRPC_COMPRESS_ALGORITHM_COUNT on failure */
+grpc_compression_algorithm grpc_compression_algorithm_from_mdstr(
+    grpc_mdstr *str);
+
+#endif /* GRPC_INTERNAL_CORE_COMPRESSION_ALGORITHM_METADATA_H */

src/core/compression/message_compress.c

@@ -69,8 +69,8 @@ static int zlib_body(z_stream* zs, gpr_slice_buffer* input,
         zs->next_out = GPR_SLICE_START_PTR(outbuf);
       }
       r = flate(zs, flush);
-      if (r == Z_STREAM_ERROR) {
-        gpr_log(GPR_INFO, "zlib: stream error");
+      if (r < 0 && r != Z_BUF_ERROR /* not fatal */) {
+        gpr_log(GPR_INFO, "zlib error (%d)", r);
         goto error;
       }
     } while (zs->avail_out == 0);
@@ -91,6 +91,12 @@ error:
   return 0;
 }
 
+static void* zalloc_gpr(void* opaque, unsigned int items, unsigned int size) {
+  return gpr_malloc(items * size);
+}
+
+static void zfree_gpr(void* opaque, void* address) { gpr_free(address); }
+
 static int zlib_compress(gpr_slice_buffer* input, gpr_slice_buffer* output,
                          int gzip) {
   z_stream zs;
@@ -99,12 +105,11 @@ static int zlib_compress(gpr_slice_buffer* input, gpr_slice_buffer* output,
   size_t count_before = output->count;
   size_t length_before = output->length;
   memset(&zs, 0, sizeof(zs));
+  zs.zalloc = zalloc_gpr;
+  zs.zfree = zfree_gpr;
   r = deflateInit2(&zs, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 15 | (gzip ? 16 : 0),
                    8, Z_DEFAULT_STRATEGY);
-  if (r != Z_OK) {
-    gpr_log(GPR_ERROR, "deflateInit2 returns %d", r);
-    return 0;
-  }
+  GPR_ASSERT(r == Z_OK);
   r = zlib_body(&zs, input, output, deflate) && output->length < input->length;
   if (!r) {
     for (i = count_before; i < output->count; i++) {
@@ -125,11 +130,10 @@ static int zlib_decompress(gpr_slice_buffer* input, gpr_slice_buffer* output,
   size_t count_before = output->count;
   size_t length_before = output->length;
   memset(&zs, 0, sizeof(zs));
+  zs.zalloc = zalloc_gpr;
+  zs.zfree = zfree_gpr;
   r = inflateInit2(&zs, 15 | (gzip ? 16 : 0));
-  if (r != Z_OK) {
-    gpr_log(GPR_ERROR, "inflateInit2 returns %d", r);
-    return 0;
-  }
+  GPR_ASSERT(r == Z_OK);
   r = zlib_body(&zs, input, output, inflate);
   if (!r) {
     for (i = count_before; i < output->count; i++) {
@@ -150,8 +154,8 @@ static int copy(gpr_slice_buffer* input, gpr_slice_buffer* output) {
   return 1;
 }
 
-int compress_inner(grpc_compression_algorithm algorithm,
-                   gpr_slice_buffer* input, gpr_slice_buffer* output) {
+static int compress_inner(grpc_compression_algorithm algorithm,
+                          gpr_slice_buffer* input, gpr_slice_buffer* output) {
   switch (algorithm) {
     case GRPC_COMPRESS_NONE:
       /* the fallback path always needs to be send uncompressed: we simply

src/core/httpcli/httpcli.c

@@ -53,6 +53,7 @@ typedef struct {
   size_t next_address;
   grpc_endpoint *ep;
   char *host;
+  char *ssl_host_override;
   gpr_timespec deadline;
   int have_read_byte;
   const grpc_httpcli_handshaker *handshaker;
@@ -106,6 +107,7 @@ static void finish(grpc_exec_ctx *exec_ctx, internal_request *req,
   }
   gpr_slice_unref(req->request_text);
   gpr_free(req->host);
+  gpr_free(req->ssl_host_override);
   grpc_iomgr_unregister_object(&req->iomgr_obj);
   gpr_slice_buffer_destroy(&req->incoming);
   gpr_slice_buffer_destroy(&req->outgoing);
@@ -180,8 +182,10 @@ static void on_connected(grpc_exec_ctx *exec_ctx, void *arg, int success) {
     next_address(exec_ctx, req);
     return;
   }
-  req->handshaker->handshake(exec_ctx, req, req->ep, req->host,
-                             on_handshake_done);
+  req->handshaker->handshake(
+      exec_ctx, req, req->ep,
+      req->ssl_host_override ? req->ssl_host_override : req->host,
+      on_handshake_done);
 }
 
 static void next_address(grpc_exec_ctx *exec_ctx, internal_request *req) {
@@ -231,6 +235,7 @@ static void internal_request_begin(
   gpr_slice_buffer_init(&req->outgoing);
   grpc_iomgr_register_object(&req->iomgr_obj, name);
   req->host = gpr_strdup(request->host);
+  req->ssl_host_override = gpr_strdup(request->ssl_host_override);
 
   grpc_pollset_set_add_pollset(exec_ctx, &req->context->pollset_set,
                                req->pollset);

src/core/httpcli/httpcli.h

@@ -74,6 +74,8 @@ extern const grpc_httpcli_handshaker grpc_httpcli_ssl;
 typedef struct grpc_httpcli_request {
   /* The host name to connect to */
   char *host;
+  /* The host to verify in the SSL handshake (or NULL) */
+  char *ssl_host_override;
   /* The path of the resource to fetch */
   char *path;
   /* Additional headers: count and key/values; the following are supplied

src/core/httpcli/httpcli_security_connector.c

@@ -68,7 +68,7 @@ static void httpcli_ssl_do_handshake(grpc_exec_ctx *exec_ctx,
   tsi_result result = TSI_OK;
   tsi_handshaker *handshaker;
   if (c->handshaker_factory == NULL) {
-    cb(exec_ctx, user_data, GRPC_SECURITY_ERROR, nonsecure_endpoint, NULL);
+    cb(exec_ctx, user_data, GRPC_SECURITY_ERROR, NULL, NULL);
     return;
   }
   result = tsi_ssl_handshaker_factory_create_handshaker(
@@ -76,17 +76,18 @@ static void httpcli_ssl_do_handshake(grpc_exec_ctx *exec_ctx,
   if (result != TSI_OK) {
     gpr_log(GPR_ERROR, "Handshaker creation failed with error %s.",
             tsi_result_to_string(result));
-    cb(exec_ctx, user_data, GRPC_SECURITY_ERROR, nonsecure_endpoint, NULL);
+    cb(exec_ctx, user_data, GRPC_SECURITY_ERROR, NULL, NULL);
   } else {
     grpc_do_security_handshake(exec_ctx, handshaker, sc, nonsecure_endpoint, cb,
                                user_data);
   }
 }
 
-static grpc_security_status httpcli_ssl_check_peer(grpc_security_connector *sc,
-                                                   tsi_peer peer,
-                                                   grpc_security_check_cb cb,
-                                                   void *user_data) {
+static void httpcli_ssl_check_peer(grpc_exec_ctx *exec_ctx,
+                                   grpc_security_connector *sc,
+                                   tsi_peer peer,
+                                   grpc_security_peer_check_cb cb,
+                                   void *user_data) {
   grpc_httpcli_ssl_channel_security_connector *c =
       (grpc_httpcli_ssl_channel_security_connector *)sc;
   grpc_security_status status = GRPC_SECURITY_OK;
@@ -98,8 +99,8 @@ static grpc_security_status httpcli_ssl_check_peer(grpc_security_connector *sc,
             c->secure_peer_name);
     status = GRPC_SECURITY_ERROR;
   }
+  cb(exec_ctx, user_data, status, NULL);
   tsi_peer_destruct(&peer);
-  return status;
 }
 
 static grpc_security_connector_vtable httpcli_ssl_vtable = {
@@ -149,8 +150,8 @@ typedef struct {
 
 static void on_secure_transport_setup_done(grpc_exec_ctx *exec_ctx, void *rp,
                                            grpc_security_status status,
-                                           grpc_endpoint *wrapped_endpoint,
-                                           grpc_endpoint *secure_endpoint) {
+                                           grpc_endpoint *secure_endpoint,
+                                           grpc_auth_context *auth_context) {
   on_done_closure *c = rp;
   if (status != GRPC_SECURITY_OK) {
     gpr_log(GPR_ERROR, "Secure transport setup failed with error %d.", status);

src/core/iomgr/endpoint_pair_posix.c

@@ -36,6 +36,7 @@
 #ifdef GPR_POSIX_SOCKET
 
 #include "src/core/iomgr/endpoint_pair.h"
+#include "src/core/iomgr/socket_utils_posix.h"
 
 #include <errno.h>
 #include <fcntl.h>
@@ -56,6 +57,8 @@ static void create_sockets(int sv[2]) {
   GPR_ASSERT(fcntl(sv[0], F_SETFL, flags | O_NONBLOCK) == 0);
   flags = fcntl(sv[1], F_GETFL, 0);
   GPR_ASSERT(fcntl(sv[1], F_SETFL, flags | O_NONBLOCK) == 0);
+  GPR_ASSERT(grpc_set_socket_no_sigpipe_if_possible(sv[0]));
+  GPR_ASSERT(grpc_set_socket_no_sigpipe_if_possible(sv[1]));
 }
 
 grpc_endpoint_pair grpc_iomgr_create_endpoint_pair(const char *name,

src/core/iomgr/fd_posix.c

@@ -43,6 +43,7 @@
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>
 
 #define CLOSURE_NOT_READY ((grpc_closure *)0)
@@ -158,7 +159,10 @@ void grpc_fd_global_shutdown(void) {
 
 grpc_fd *grpc_fd_create(int fd, const char *name) {
   grpc_fd *r = alloc_fd(fd);
-  grpc_iomgr_register_object(&r->iomgr_object, name);
+  char *name2;
+  gpr_asprintf(&name2, "%s fd=%d", name, fd);
+  grpc_iomgr_register_object(&r->iomgr_object, name2);
+  gpr_free(name2);
 #ifdef GRPC_FD_REF_COUNT_DEBUG
   gpr_log(GPR_DEBUG, "FD %d %p create %s", fd, r, name);
 #endif
@@ -207,14 +211,21 @@ static int has_watchers(grpc_fd *fd) {
 }
 
 void grpc_fd_orphan(grpc_exec_ctx *exec_ctx, grpc_fd *fd, grpc_closure *on_done,
-                    const char *reason) {
+                    int *release_fd, const char *reason) {
   fd->on_done_closure = on_done;
-  shutdown(fd->fd, SHUT_RDWR);
+  fd->released = release_fd != NULL;
+  if (!fd->released) {
+    shutdown(fd->fd, SHUT_RDWR);
+  } else {
+    *release_fd = fd->fd;
+  }
   gpr_mu_lock(&fd->mu);
   REF_BY(fd, 1, reason); /* remove active status, but keep referenced */
   if (!has_watchers(fd)) {
     fd->closed = 1;
-    close(fd->fd);
+    if (!fd->released) {
+      close(fd->fd);
+    }
     grpc_exec_ctx_enqueue(exec_ctx, fd->on_done_closure, 1);
   } else {
     wake_all_watchers_locked(fd);
@@ -406,7 +417,9 @@ void grpc_fd_end_poll(grpc_exec_ctx *exec_ctx, grpc_fd_watcher *watcher,
   }
   if (grpc_fd_is_orphaned(fd) && !has_watchers(fd) && !fd->closed) {
     fd->closed = 1;
-    close(fd->fd);
+    if (!fd->released) {
+      close(fd->fd);
+    }
     grpc_exec_ctx_enqueue(exec_ctx, fd->on_done_closure, 1);
   }
   gpr_mu_unlock(&fd->mu);

src/core/iomgr/fd_posix.h

@@ -62,6 +62,7 @@ struct grpc_fd {
   gpr_mu mu;
   int shutdown;
   int closed;
+  int released;
 
   /* The watcher list.
 
@@ -107,11 +108,12 @@ grpc_fd *grpc_fd_create(int fd, const char *name);
 /* Releases fd to be asynchronously destroyed.
    on_done is called when the underlying file descriptor is definitely close()d.
    If on_done is NULL, no callback will be made.
+   If release_fd is not NULL, it's set to fd and fd will not be closed.
    Requires: *fd initialized; no outstanding notify_on_read or
    notify_on_write.
    MUST NOT be called with a pollset lock taken */
 void grpc_fd_orphan(grpc_exec_ctx *exec_ctx, grpc_fd *fd, grpc_closure *on_done,
-                    const char *reason);
+                    int *release_fd, const char *reason);
 
 /* Begin polling on an fd.
    Registers that the given pollset is interested in this fd - so that if read
@@ -168,6 +170,7 @@ void grpc_fd_become_readable(grpc_exec_ctx *exec_ctx, grpc_fd *fd);
 void grpc_fd_become_writable(grpc_exec_ctx *exec_ctx, grpc_fd *fd);
 
 /* Reference counting for fds */
+/*#define GRPC_FD_REF_COUNT_DEBUG*/
 #ifdef GRPC_FD_REF_COUNT_DEBUG
 void grpc_fd_ref(grpc_fd *fd, const char *reason, const char *file, int line);
 void grpc_fd_unref(grpc_fd *fd, const char *reason, const char *file, int line);

src/core/iomgr/pollset_multipoller_with_epoll.c

@@ -123,26 +123,6 @@ static void multipoll_with_epoll_pollset_add_fd(grpc_exec_ctx *exec_ctx,
   }
 }
 
-static void multipoll_with_epoll_pollset_del_fd(grpc_exec_ctx *exec_ctx,
-                                                grpc_pollset *pollset,
-                                                grpc_fd *fd,
-                                                int and_unlock_pollset) {
-  pollset_hdr *h = pollset->data.ptr;
-  int err;
-
-  if (and_unlock_pollset) {
-    gpr_mu_unlock(&pollset->mu);
-  }
-
-  /* Note that this can race with concurrent poll, but that should be fine since
-   * at worst it creates a spurious read event on a reused grpc_fd object. */
-  err = epoll_ctl(h->epoll_fd, EPOLL_CTL_DEL, fd->fd, NULL);
-  if (err < 0) {
-    gpr_log(GPR_ERROR, "epoll_ctl del for %d failed: %s", fd->fd,
-            strerror(errno));
-  }
-}
-
 /* TODO(klempner): We probably want to turn this down a bit */
 #define GRPC_EPOLL_MAX_EVENTS 1000
 
@@ -235,7 +215,7 @@ static void multipoll_with_epoll_pollset_destroy(grpc_pollset *pollset) {
 }
 
 static const grpc_pollset_vtable multipoll_with_epoll_pollset = {
-    multipoll_with_epoll_pollset_add_fd, multipoll_with_epoll_pollset_del_fd,
+    multipoll_with_epoll_pollset_add_fd,
     multipoll_with_epoll_pollset_maybe_work_and_unlock,
     multipoll_with_epoll_pollset_finish_shutdown,
     multipoll_with_epoll_pollset_destroy};

src/core/iomgr/pollset_multipoller_with_poll_posix.c

@@ -82,23 +82,6 @@ exit:
   }
 }
 
-static void multipoll_with_poll_pollset_del_fd(grpc_exec_ctx *exec_ctx,
-                                               grpc_pollset *pollset,
-                                               grpc_fd *fd,
-                                               int and_unlock_pollset) {
-  /* will get removed next poll cycle */
-  pollset_hdr *h = pollset->data.ptr;
-  if (h->del_count == h->del_capacity) {
-    h->del_capacity = GPR_MAX(h->del_capacity + 8, h->del_count * 3 / 2);
-    h->dels = gpr_realloc(h->dels, sizeof(grpc_fd *) * h->del_capacity);
-  }
-  h->dels[h->del_count++] = fd;
-  GRPC_FD_REF(fd, "multipoller_del");
-  if (and_unlock_pollset) {
-    gpr_mu_unlock(&pollset->mu);
-  }
-}
-
 static void multipoll_with_poll_pollset_maybe_work_and_unlock(
     grpc_exec_ctx *exec_ctx, grpc_pollset *pollset, grpc_pollset_worker *worker,
     gpr_timespec deadline, gpr_timespec now) {
@@ -212,7 +195,7 @@ static void multipoll_with_poll_pollset_destroy(grpc_pollset *pollset) {
 }
 
 static const grpc_pollset_vtable multipoll_with_poll_pollset = {
-    multipoll_with_poll_pollset_add_fd, multipoll_with_poll_pollset_del_fd,
+    multipoll_with_poll_pollset_add_fd,
     multipoll_with_poll_pollset_maybe_work_and_unlock,
     multipoll_with_poll_pollset_finish_shutdown,
     multipoll_with_poll_pollset_destroy};

src/core/iomgr/pollset_posix.c

@@ -232,21 +232,7 @@ void grpc_pollset_add_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
   gpr_mu_lock(&pollset->mu);
   pollset->vtable->add_fd(exec_ctx, pollset, fd, 1);
 /* the following (enabled only in debug) will reacquire and then release
-   our lock - meaning that if the unlocking flag passed to del_fd above is
-   not respected, the code will deadlock (in a way that we have a chance of
-   debugging) */
-#ifndef NDEBUG
-  gpr_mu_lock(&pollset->mu);
-  gpr_mu_unlock(&pollset->mu);
-#endif
-}
-
-void grpc_pollset_del_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                         grpc_fd *fd) {
-  gpr_mu_lock(&pollset->mu);
-  pollset->vtable->del_fd(exec_ctx, pollset, fd, 1);
-/* the following (enabled only in debug) will reacquire and then release
-   our lock - meaning that if the unlocking flag passed to del_fd above is
+   our lock - meaning that if the unlocking flag passed to add_fd above is
    not respected, the code will deadlock (in a way that we have a chance of
    debugging) */
 #ifndef NDEBUG
@@ -547,19 +533,6 @@ exit:
   }
 }
 
-static void basic_pollset_del_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                                 grpc_fd *fd, int and_unlock_pollset) {
-  GPR_ASSERT(fd);
-  if (fd == pollset->data.ptr) {
-    GRPC_FD_UNREF(pollset->data.ptr, "basicpoll");
-    pollset->data.ptr = NULL;
-  }
-
-  if (and_unlock_pollset) {
-    gpr_mu_unlock(&pollset->mu);
-  }
-}
-
 static void basic_pollset_maybe_work_and_unlock(grpc_exec_ctx *exec_ctx,
                                                 grpc_pollset *pollset,
                                                 grpc_pollset_worker *worker,
@@ -613,7 +586,9 @@ static void basic_pollset_maybe_work_and_unlock(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_END("poll", 0);
 
   if (r < 0) {
-    gpr_log(GPR_ERROR, "poll() failed: %s", strerror(errno));
+    if (errno != EINTR) {
+      gpr_log(GPR_ERROR, "poll() failed: %s", strerror(errno));
+    }
     if (fd) {
       grpc_fd_end_poll(exec_ctx, &fd_watcher, 0, 0);
     }
@@ -649,9 +624,8 @@ static void basic_pollset_destroy(grpc_pollset *pollset) {
 }
 
 static const grpc_pollset_vtable basic_pollset = {
-    basic_pollset_add_fd, basic_pollset_del_fd,
-    basic_pollset_maybe_work_and_unlock, basic_pollset_destroy,
-    basic_pollset_destroy};
+    basic_pollset_add_fd, basic_pollset_maybe_work_and_unlock,
+    basic_pollset_destroy, basic_pollset_destroy};
 
 static void become_basic_pollset(grpc_pollset *pollset, grpc_fd *fd_or_null) {
   pollset->vtable = &basic_pollset;

src/core/iomgr/pollset_posix.h

@@ -86,8 +86,6 @@ typedef struct grpc_pollset {
 struct grpc_pollset_vtable {
   void (*add_fd)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                  struct grpc_fd *fd, int and_unlock_pollset);
-  void (*del_fd)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                 struct grpc_fd *fd, int and_unlock_pollset);
   void (*maybe_work_and_unlock)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                                 grpc_pollset_worker *worker,
                                 gpr_timespec deadline, gpr_timespec now);
@@ -100,10 +98,6 @@ struct grpc_pollset_vtable {
 /* Add an fd to a pollset */
 void grpc_pollset_add_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                          struct grpc_fd *fd);
-/* Force remove an fd from a pollset (normally they are removed on the next
-   poll after an fd is orphaned) */
-void grpc_pollset_del_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                         struct grpc_fd *fd);
 
 /* Returns the fd to listen on for kicks */
 int grpc_kick_read_fd(grpc_pollset *p);

src/core/iomgr/pollset_set.h

@@ -49,13 +49,19 @@
 #include "src/core/iomgr/pollset_set_windows.h"
 #endif
 
-void grpc_pollset_set_init(grpc_pollset_set* pollset_set);
-void grpc_pollset_set_destroy(grpc_pollset_set* pollset_set);
-void grpc_pollset_set_add_pollset(grpc_exec_ctx* exec_ctx,
-                                  grpc_pollset_set* pollset_set,
-                                  grpc_pollset* pollset);
-void grpc_pollset_set_del_pollset(grpc_exec_ctx* exec_ctx,
-                                  grpc_pollset_set* pollset_set,
-                                  grpc_pollset* pollset);
+void grpc_pollset_set_init(grpc_pollset_set *pollset_set);
+void grpc_pollset_set_destroy(grpc_pollset_set *pollset_set);
+void grpc_pollset_set_add_pollset(grpc_exec_ctx *exec_ctx,
+                                  grpc_pollset_set *pollset_set,
+                                  grpc_pollset *pollset);
+void grpc_pollset_set_del_pollset(grpc_exec_ctx *exec_ctx,
+                                  grpc_pollset_set *pollset_set,
+                                  grpc_pollset *pollset);
+void grpc_pollset_set_add_pollset_set(grpc_exec_ctx *exec_ctx,
+                                      grpc_pollset_set *bag,
+                                      grpc_pollset_set *item);
+void grpc_pollset_set_del_pollset_set(grpc_exec_ctx *exec_ctx,
+                                      grpc_pollset_set *bag,
+                                      grpc_pollset_set *item);
 
 #endif /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_H */

src/core/iomgr/pollset_set_posix.c

@@ -52,9 +52,10 @@ void grpc_pollset_set_destroy(grpc_pollset_set *pollset_set) {
   size_t i;
   gpr_mu_destroy(&pollset_set->mu);
   for (i = 0; i < pollset_set->fd_count; i++) {
-    GRPC_FD_UNREF(pollset_set->fds[i], "pollset");
+    GRPC_FD_UNREF(pollset_set->fds[i], "pollset_set");
   }
   gpr_free(pollset_set->pollsets);
+  gpr_free(pollset_set->pollset_sets);
   gpr_free(pollset_set->fds);
 }
 
@@ -73,7 +74,7 @@ void grpc_pollset_set_add_pollset(grpc_exec_ctx *exec_ctx,
   pollset_set->pollsets[pollset_set->pollset_count++] = pollset;
   for (i = 0, j = 0; i < pollset_set->fd_count; i++) {
     if (grpc_fd_is_orphaned(pollset_set->fds[i])) {
-      GRPC_FD_UNREF(pollset_set->fds[i], "pollset");
+      GRPC_FD_UNREF(pollset_set->fds[i], "pollset_set");
     } else {
       grpc_pollset_add_fd(exec_ctx, pollset, pollset_set->fds[i]);
       pollset_set->fds[j++] = pollset_set->fds[i];
@@ -99,6 +100,46 @@ void grpc_pollset_set_del_pollset(grpc_exec_ctx *exec_ctx,
   gpr_mu_unlock(&pollset_set->mu);
 }
 
+void grpc_pollset_set_add_pollset_set(grpc_exec_ctx *exec_ctx,
+                                      grpc_pollset_set *bag,
+                                      grpc_pollset_set *item) {
+  size_t i, j;
+  gpr_mu_lock(&bag->mu);
+  if (bag->pollset_set_count == bag->pollset_set_capacity) {
+    bag->pollset_set_capacity = GPR_MAX(8, 2 * bag->pollset_set_capacity);
+    bag->pollset_sets =
+        gpr_realloc(bag->pollset_sets,
+                    bag->pollset_set_capacity * sizeof(*bag->pollset_sets));
+  }
+  bag->pollset_sets[bag->pollset_set_count++] = item;
+  for (i = 0, j = 0; i < bag->fd_count; i++) {
+    if (grpc_fd_is_orphaned(bag->fds[i])) {
+      GRPC_FD_UNREF(bag->fds[i], "pollset_set");
+    } else {
+      grpc_pollset_set_add_fd(exec_ctx, item, bag->fds[i]);
+      bag->fds[j++] = bag->fds[i];
+    }
+  }
+  bag->fd_count = j;
+  gpr_mu_unlock(&bag->mu);
+}
+
+void grpc_pollset_set_del_pollset_set(grpc_exec_ctx *exec_ctx,
+                                      grpc_pollset_set *bag,
+                                      grpc_pollset_set *item) {
+  size_t i;
+  gpr_mu_lock(&bag->mu);
+  for (i = 0; i < bag->pollset_set_count; i++) {
+    if (bag->pollset_sets[i] == item) {
+      bag->pollset_set_count--;
+      GPR_SWAP(grpc_pollset_set *, bag->pollset_sets[i],
+               bag->pollset_sets[bag->pollset_set_count]);
+      break;
+    }
+  }
+  gpr_mu_unlock(&bag->mu);
+}
+
 void grpc_pollset_set_add_fd(grpc_exec_ctx *exec_ctx,
                              grpc_pollset_set *pollset_set, grpc_fd *fd) {
   size_t i;
@@ -113,6 +154,9 @@ void grpc_pollset_set_add_fd(grpc_exec_ctx *exec_ctx,
   for (i = 0; i < pollset_set->pollset_count; i++) {
     grpc_pollset_add_fd(exec_ctx, pollset_set->pollsets[i], fd);
   }
+  for (i = 0; i < pollset_set->pollset_set_count; i++) {
+    grpc_pollset_set_add_fd(exec_ctx, pollset_set->pollset_sets[i], fd);
+  }
   gpr_mu_unlock(&pollset_set->mu);
 }
 
@@ -129,6 +173,9 @@ void grpc_pollset_set_del_fd(grpc_exec_ctx *exec_ctx,
       break;
     }
   }
+  for (i = 0; i < pollset_set->pollset_set_count; i++) {
+    grpc_pollset_set_del_fd(exec_ctx, pollset_set->pollset_sets[i], fd);
+  }
   gpr_mu_unlock(&pollset_set->mu);
 }
 

src/core/iomgr/pollset_set_posix.h

@@ -44,6 +44,10 @@ typedef struct grpc_pollset_set {
   size_t pollset_capacity;
   grpc_pollset **pollsets;
 
+  size_t pollset_set_count;
+  size_t pollset_set_capacity;
+  struct grpc_pollset_set **pollset_sets;
+
   size_t fd_count;
   size_t fd_capacity;
   grpc_fd **fds;

src/core/iomgr/pollset_set_windows.c

@@ -49,4 +49,12 @@ void grpc_pollset_set_del_pollset(grpc_exec_ctx* exec_ctx,
                                   grpc_pollset_set* pollset_set,
                                   grpc_pollset* pollset) {}
 
+void grpc_pollset_set_add_pollset_set(grpc_exec_ctx* exec_ctx,
+                                      grpc_pollset_set* bag,
+                                      grpc_pollset_set* item) {}
+
+void grpc_pollset_set_del_pollset_set(grpc_exec_ctx* exec_ctx,
+                                      grpc_pollset_set* bag,
+                                      grpc_pollset_set* item) {}
+
 #endif /* GPR_WINSOCK_SOCKET */

src/core/iomgr/tcp_client_posix.c

@@ -196,7 +196,7 @@ static void on_writable(grpc_exec_ctx *exec_ctx, void *acp, int success) {
 finish:
   if (fd != NULL) {
     grpc_pollset_set_del_fd(exec_ctx, ac->interested_parties, fd);
-    grpc_fd_orphan(exec_ctx, fd, NULL, "tcp_client_orphan");
+    grpc_fd_orphan(exec_ctx, fd, NULL, NULL, "tcp_client_orphan");
     fd = NULL;
   }
   done = (--ac->refs == 0);
@@ -265,7 +265,7 @@ void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
 
   if (errno != EWOULDBLOCK && errno != EINPROGRESS) {
     gpr_log(GPR_ERROR, "connect error to '%s': %s", addr_str, strerror(errno));
-    grpc_fd_orphan(exec_ctx, fdobj, NULL, "tcp_client_connect_error");
+    grpc_fd_orphan(exec_ctx, fdobj, NULL, NULL, "tcp_client_connect_error");
     grpc_exec_ctx_enqueue(exec_ctx, closure, 0);
     goto done;
   }

src/core/iomgr/tcp_posix.c

@@ -90,6 +90,8 @@ typedef struct {
 
   grpc_closure *read_cb;
   grpc_closure *write_cb;
+  grpc_closure *release_fd_cb;
+  int *release_fd;
 
   grpc_closure read_closure;
   grpc_closure write_closure;
@@ -108,7 +110,8 @@ static void tcp_shutdown(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep) {
 }
 
 static void tcp_free(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
-  grpc_fd_orphan(exec_ctx, tcp->em_fd, NULL, "tcp_unref_orphan");
+  grpc_fd_orphan(exec_ctx, tcp->em_fd, tcp->release_fd_cb, tcp->release_fd,
+                 "tcp_unref_orphan");
   gpr_slice_buffer_destroy(&tcp->last_read_buffer);
   gpr_free(tcp->peer_string);
   gpr_free(tcp);
@@ -452,6 +455,8 @@ grpc_endpoint *grpc_tcp_create(grpc_fd *em_fd, size_t slice_size,
   tcp->fd = em_fd->fd;
   tcp->read_cb = NULL;
   tcp->write_cb = NULL;
+  tcp->release_fd_cb = NULL;
+  tcp->release_fd = NULL;
   tcp->incoming_buffer = NULL;
   tcp->slice_size = slice_size;
   tcp->iov_size = 1;
@@ -468,4 +473,13 @@ grpc_endpoint *grpc_tcp_create(grpc_fd *em_fd, size_t slice_size,
   return &tcp->base;
 }
 
+void grpc_tcp_destroy_and_release_fd(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
+                                     int *fd, grpc_closure *done) {
+  grpc_tcp *tcp = (grpc_tcp *)ep;
+  GPR_ASSERT(ep->vtable == &vtable);
+  tcp->release_fd = fd;
+  tcp->release_fd_cb = done;
+  TCP_UNREF(exec_ctx, tcp, "destroy");
+}
+
 #endif

src/core/iomgr/tcp_posix.h

@@ -56,4 +56,10 @@ extern int grpc_tcp_trace;
 grpc_endpoint *grpc_tcp_create(grpc_fd *fd, size_t read_slice_size,
                                const char *peer_string);
 
+/* Destroy the tcp endpoint without closing its fd. *fd will be set and done
+ * will be called when the endpoint is destroyed.
+ * Requires: ep must be a tcp endpoint and fd must not be NULL. */
+void grpc_tcp_destroy_and_release_fd(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
+                                     int *fd, grpc_closure *done);
+
 #endif /* GRPC_INTERNAL_CORE_IOMGR_TCP_POSIX_H */

src/core/iomgr/tcp_server_posix.c

@@ -193,7 +193,7 @@ static void deactivated_all_ports(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
       }
       sp->destroyed_closure.cb = destroyed_port;
       sp->destroyed_closure.cb_arg = s;
-      grpc_fd_orphan(exec_ctx, sp->emfd, &sp->destroyed_closure,
+      grpc_fd_orphan(exec_ctx, sp->emfd, &sp->destroyed_closure, NULL,
                      "tcp_listener_shutdown");
     }
     gpr_mu_unlock(&s->mu);
@@ -411,7 +411,6 @@ static grpc_tcp_listener *add_socket_to_server(grpc_tcp_server *s, int fd,
 
 grpc_tcp_listener *grpc_tcp_server_add_port(grpc_tcp_server *s,
                                             const void *addr, size_t addr_len) {
-  int allocated_port = -1;
   grpc_tcp_listener *sp;
   grpc_tcp_listener *sp2 = NULL;
   int fd;
@@ -464,14 +463,13 @@ grpc_tcp_listener *grpc_tcp_server_add_port(grpc_tcp_server *s,
     addr_len = sizeof(wild6);
     fd = grpc_create_dualstack_socket(addr, SOCK_STREAM, 0, &dsmode);
     sp = add_socket_to_server(s, fd, addr, addr_len);
-    allocated_port = sp->port;
     if (fd >= 0 && dsmode == GRPC_DSMODE_DUALSTACK) {
       goto done;
     }
 
     /* If we didn't get a dualstack socket, also listen on 0.0.0.0. */
-    if (port == 0 && allocated_port > 0) {
-      grpc_sockaddr_set_port((struct sockaddr *)&wild4, allocated_port);
+    if (port == 0 && sp != NULL) {
+      grpc_sockaddr_set_port((struct sockaddr *)&wild4, sp->port);
       sp2 = sp;
     }
     addr = (struct sockaddr *)&wild4;
@@ -488,8 +486,8 @@ grpc_tcp_listener *grpc_tcp_server_add_port(grpc_tcp_server *s,
     addr_len = sizeof(addr4_copy);
   }
   sp = add_socket_to_server(s, fd, addr, addr_len);
-  sp->sibling = sp2;
-  if (sp2) sp2->is_sibling = 1;
+  if (sp != NULL) sp->sibling = sp2;
+  if (sp2 != NULL) sp2->is_sibling = 1;
 
 done:
   gpr_free(allocated_addr);
@@ -534,8 +532,12 @@ void grpc_tcp_server_start(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s,
 }
 
 int grpc_tcp_listener_get_port(grpc_tcp_listener *listener) {
-  grpc_tcp_listener *sp = listener;
-  return sp->port;
+  if (listener != NULL) {
+    grpc_tcp_listener *sp = listener;
+    return sp->port;
+  } else {
+    return 0;
+  }
 }
 
 void grpc_tcp_listener_ref(grpc_tcp_listener *listener) {

src/core/iomgr/tcp_server_windows.c

@@ -486,8 +486,12 @@ void grpc_tcp_server_start(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s,
 }
 
 int grpc_tcp_listener_get_port(grpc_tcp_listener *listener) {
-  grpc_tcp_listener *sp = listener;
-  return sp->port;
+  if (listener != NULL) {
+    grpc_tcp_listener *sp = listener;
+    return sp->port;
+  } else {
+    return 0;
+  }
 }
 
 void grpc_tcp_listener_ref(grpc_tcp_listener *listener) {

src/core/iomgr/tcp_windows.c

@@ -197,7 +197,8 @@ static void win_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
 
   tcp->read_slice = gpr_slice_malloc(8192);
 
-  buffer.len = GPR_SLICE_LENGTH(tcp->read_slice);
+  buffer.len = (ULONG)GPR_SLICE_LENGTH(
+      tcp->read_slice);  // we know slice size fits in 32bit.
   buffer.buf = (char *)GPR_SLICE_START_PTR(tcp->read_slice);
 
   TCP_REF(tcp, "read");
@@ -273,6 +274,7 @@ static void win_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   WSABUF local_buffers[16];
   WSABUF *allocated = NULL;
   WSABUF *buffers = local_buffers;
+  size_t len;
 
   if (tcp->shutting_down) {
     grpc_exec_ctx_enqueue(exec_ctx, cb, 0);
@@ -281,19 +283,21 @@ static void win_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
 
   tcp->write_cb = cb;
   tcp->write_slices = slices;
-
+  GPR_ASSERT(tcp->write_slices->count <= UINT_MAX);
   if (tcp->write_slices->count > GPR_ARRAY_SIZE(local_buffers)) {
     buffers = (WSABUF *)gpr_malloc(sizeof(WSABUF) * tcp->write_slices->count);
     allocated = buffers;
   }
 
   for (i = 0; i < tcp->write_slices->count; i++) {
-    buffers[i].len = GPR_SLICE_LENGTH(tcp->write_slices->slices[i]);
+    len = GPR_SLICE_LENGTH(tcp->write_slices->slices[i]);
+    GPR_ASSERT(len <= ULONG_MAX);
+    buffers[i].len = (ULONG)len;
     buffers[i].buf = (char *)GPR_SLICE_START_PTR(tcp->write_slices->slices[i]);
   }
 
   /* First, let's try a synchronous, non-blocking write. */
-  status = WSASend(socket->socket, buffers, tcp->write_slices->count,
+  status = WSASend(socket->socket, buffers, (DWORD)tcp->write_slices->count,
                    &bytes_sent, 0, NULL, NULL);
   info->wsa_error = status == 0 ? 0 : WSAGetLastError();
 
@@ -322,7 +326,7 @@ static void win_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   /* If we got a WSAEWOULDBLOCK earlier, then we need to re-do the same
      operation, this time asynchronously. */
   memset(&socket->write_info.overlapped, 0, sizeof(OVERLAPPED));
-  status = WSASend(socket->socket, buffers, tcp->write_slices->count,
+  status = WSASend(socket->socket, buffers, (DWORD)tcp->write_slices->count,
                    &bytes_sent, 0, &socket->write_info.overlapped, NULL);
   if (allocated) gpr_free(allocated);
 

src/core/iomgr/timer.c

@@ -126,8 +126,8 @@ static double ts_to_dbl(gpr_timespec ts) {
 
 static gpr_timespec dbl_to_ts(double d) {
   gpr_timespec ts;
-  ts.tv_sec = (time_t)d;
-  ts.tv_nsec = (int)(1e9 * (d - (double)ts.tv_sec));
+  ts.tv_sec = (gpr_int64)d;
+  ts.tv_nsec = (gpr_int32)(1e9 * (d - (double)ts.tv_sec));
   ts.clock_type = GPR_TIMESPAN;
   return ts;
 }
@@ -343,11 +343,3 @@ int grpc_timer_check(grpc_exec_ctx *exec_ctx, gpr_timespec now,
       exec_ctx, now, next,
       gpr_time_cmp(now, gpr_inf_future(now.clock_type)) != 0);
 }
-
-gpr_timespec grpc_timer_list_next_timeout(void) {
-  gpr_timespec out;
-  gpr_mu_lock(&g_mu);
-  out = g_shard_queue[0]->min_deadline;
-  gpr_mu_unlock(&g_mu);
-  return out;
-}

src/core/iomgr/timer_internal.h

@@ -54,8 +54,6 @@ int grpc_timer_check(grpc_exec_ctx* exec_ctx, gpr_timespec now,
 void grpc_timer_list_init(gpr_timespec now);
 void grpc_timer_list_shutdown(grpc_exec_ctx* exec_ctx);
 
-gpr_timespec grpc_timer_list_next_timeout(void);
-
 /* the following must be implemented by each iomgr implementation */
 
 void grpc_kick_poller(void);

src/core/iomgr/udp_server.c

@@ -38,6 +38,7 @@
 
 #include <grpc/support/port_platform.h>
 
+#ifdef GRPC_NEED_UDP
 #ifdef GPR_POSIX_SOCKET
 
 #include "src/core/iomgr/udp_server.h"
@@ -179,7 +180,7 @@ static void deactivated_all_ports(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
       }
       sp->destroyed_closure.cb = destroyed_port;
       sp->destroyed_closure.cb_arg = s;
-      grpc_fd_orphan(exec_ctx, sp->emfd, &sp->destroyed_closure,
+      grpc_fd_orphan(exec_ctx, sp->emfd, &sp->destroyed_closure, NULL,
                      "udp_listener_shutdown");
     }
     gpr_mu_unlock(&s->mu);
@@ -435,3 +436,4 @@ void grpc_udp_server_write(server_port *sp, const char *buffer, size_t buf_len,
 }
 
 #endif
+#endif

src/core/iomgr/wakeup_fd_posix.c

@@ -40,19 +40,17 @@
 #include <stddef.h>
 
 static const grpc_wakeup_fd_vtable *wakeup_fd_vtable = NULL;
+int grpc_allow_specialized_wakeup_fd = 1;
 
 void grpc_wakeup_fd_global_init(void) {
-  if (grpc_specialized_wakeup_fd_vtable.check_availability()) {
+  if (grpc_allow_specialized_wakeup_fd &&
+      grpc_specialized_wakeup_fd_vtable.check_availability()) {
     wakeup_fd_vtable = &grpc_specialized_wakeup_fd_vtable;
   } else {
     wakeup_fd_vtable = &grpc_pipe_wakeup_fd_vtable;
   }
 }
 
-void grpc_wakeup_fd_global_init_force_fallback(void) {
-  wakeup_fd_vtable = &grpc_pipe_wakeup_fd_vtable;
-}
-
 void grpc_wakeup_fd_global_destroy(void) { wakeup_fd_vtable = NULL; }
 
 void grpc_wakeup_fd_init(grpc_wakeup_fd *fd_info) {

src/core/iomgr/wakeup_fd_posix.h

@@ -85,6 +85,8 @@ struct grpc_wakeup_fd {
   int write_fd;
 };
 
+extern int grpc_allow_specialized_wakeup_fd;
+
 #define GRPC_WAKEUP_FD_GET_READ_FD(fd_info) ((fd_info)->read_fd)
 
 void grpc_wakeup_fd_init(grpc_wakeup_fd* fd_info);

src/core/iomgr/workqueue_posix.c

@@ -103,6 +103,9 @@ void grpc_workqueue_add_to_pollset(grpc_exec_ctx *exec_ctx,
 
 void grpc_workqueue_flush(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue) {
   gpr_mu_lock(&workqueue->mu);
+  if (grpc_closure_list_empty(workqueue->closure_list)) {
+    grpc_wakeup_fd_wakeup(&workqueue->wakeup_fd);
+  }
   grpc_closure_list_move(&exec_ctx->closure_list, &workqueue->closure_list);
   gpr_mu_unlock(&workqueue->mu);
 }
@@ -115,7 +118,7 @@ static void on_readable(grpc_exec_ctx *exec_ctx, void *arg, int success) {
     /* HACK: let wakeup_fd code know that we stole the fd */
     workqueue->wakeup_fd.read_fd = 0;
     grpc_wakeup_fd_destroy(&workqueue->wakeup_fd);
-    grpc_fd_orphan(exec_ctx, workqueue->wakeup_read_fd, NULL, "destroy");
+    grpc_fd_orphan(exec_ctx, workqueue->wakeup_read_fd, NULL, NULL, "destroy");
     gpr_free(workqueue);
   } else {
     gpr_mu_lock(&workqueue->mu);

src/core/json/json_reader.c

@@ -35,6 +35,8 @@
 
 #include <grpc/support/port_platform.h>
 
+#include <grpc/support/log.h>
+
 #include "src/core/json/json_reader.h"
 
 static void json_reader_string_clear(grpc_json_reader *reader) {
@@ -224,13 +226,13 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader *reader) {
                   reader->in_array = 1;
                   break;
                 case GRPC_JSON_TOP_LEVEL:
-                  if (reader->depth != 0) return GRPC_JSON_INTERNAL_ERROR;
+                  GPR_ASSERT(reader->depth == 0);
                   reader->in_object = 0;
                   reader->in_array = 0;
                   reader->state = GRPC_JSON_STATE_END;
                   break;
                 default:
-                  return GRPC_JSON_INTERNAL_ERROR;
+                  GPR_UNREACHABLE_CODE(return GRPC_JSON_INTERNAL_ERROR);
               }
             }
             break;
@@ -279,8 +281,7 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader *reader) {
             break;
 
           case GRPC_JSON_STATE_OBJECT_KEY_STRING:
-            if (reader->unicode_high_surrogate != 0)
-              return GRPC_JSON_PARSE_ERROR;
+            GPR_ASSERT(reader->unicode_high_surrogate == 0);
             if (c == '"') {
               reader->state = GRPC_JSON_STATE_OBJECT_KEY_END;
               json_reader_set_key(reader);
@@ -461,7 +462,7 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader *reader) {
                 }
                 break;
               default:
-                return GRPC_JSON_INTERNAL_ERROR;
+                GPR_UNREACHABLE_CODE(return GRPC_JSON_INTERNAL_ERROR);
             }
             break;
 
@@ -641,7 +642,7 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader *reader) {
               case ',':
               case '}':
               case ']':
-                return GRPC_JSON_INTERNAL_ERROR;
+                GPR_UNREACHABLE_CODE(return GRPC_JSON_INTERNAL_ERROR);
                 break;
 
               default:
@@ -655,5 +656,5 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader *reader) {
     }
   }
 
-  return GRPC_JSON_INTERNAL_ERROR;
+  GPR_UNREACHABLE_CODE(return GRPC_JSON_INTERNAL_ERROR);
 }

src/core/json/json_string.c

@@ -353,7 +353,7 @@ static void json_dump_recursive(grpc_json_writer *writer, grpc_json *json,
         grpc_json_writer_value_raw_with_len(writer, "null", 4);
         break;
       default:
-        abort();
+        GPR_UNREACHABLE_CODE(abort());
     }
     json = json->next;
   }

src/core/profiling/basic_timers.c

@@ -141,10 +141,11 @@ static void write_log(gpr_timer_log *log) {
       entry->tm = gpr_time_0(entry->tm.clock_type);
     }
     fprintf(output_file,
-            "{\"t\": %ld.%09d, \"thd\": \"%d\", \"type\": \"%c\", \"tag\": "
+            "{\"t\": %lld.%09d, \"thd\": \"%d\", \"type\": \"%c\", \"tag\": "
             "\"%s\", \"file\": \"%s\", \"line\": %d, \"imp\": %d}\n",
-            entry->tm.tv_sec, entry->tm.tv_nsec, entry->thd, entry->type,
-            entry->tagstr, entry->file, entry->line, entry->important);
+            (long long)entry->tm.tv_sec, (int)entry->tm.tv_nsec, entry->thd,
+            entry->type, entry->tagstr, entry->file, entry->line,
+            entry->important);
   }
 }
 

src/core/security/client_auth_filter.c

@@ -39,12 +39,13 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
-#include "src/core/support/string.h"
 #include "src/core/channel/channel_stack.h"
-#include "src/core/security/security_context.h"
-#include "src/core/security/security_connector.h"
 #include "src/core/security/credentials.h"
+#include "src/core/security/security_connector.h"
+#include "src/core/security/security_context.h"
+#include "src/core/support/string.h"
 #include "src/core/surface/call.h"
+#include "src/core/transport/static_metadata.h"
 
 #define MAX_CREDENTIALS_METADATA_COUNT 4
 
@@ -61,24 +62,29 @@ typedef struct {
   grpc_transport_stream_op op;
   gpr_uint8 security_context_set;
   grpc_linked_mdelem md_links[MAX_CREDENTIALS_METADATA_COUNT];
-  char *service_url;
+  grpc_auth_metadata_context auth_md_context;
 } call_data;
 
 /* We can have a per-channel credentials. */
 typedef struct {
   grpc_channel_security_connector *security_connector;
-  grpc_mdctx *md_ctx;
-  grpc_mdstr *authority_string;
-  grpc_mdstr *path_string;
-  grpc_mdstr *error_msg_key;
-  grpc_mdstr *status_key;
+  grpc_auth_context *auth_context;
 } channel_data;
 
-static void reset_service_url(call_data *calld) {
-  if (calld->service_url != NULL) {
-    gpr_free(calld->service_url);
-    calld->service_url = NULL;
+static void reset_auth_metadata_context(
+    grpc_auth_metadata_context *auth_md_context) {
+  if (auth_md_context->service_url != NULL) {
+    gpr_free((char *)auth_md_context->service_url);
+    auth_md_context->service_url = NULL;
+  }
+  if (auth_md_context->method_name != NULL) {
+    gpr_free((char *)auth_md_context->method_name);
+    auth_md_context->method_name = NULL;
   }
+  GRPC_AUTH_CONTEXT_UNREF(
+      (grpc_auth_context *)auth_md_context->channel_auth_context,
+      "grpc_auth_metadata_context");
+  auth_md_context->channel_auth_context = NULL;
 }
 
 static void bubble_up_error(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
@@ -95,11 +101,10 @@ static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *user_data,
                                     grpc_credentials_status status) {
   grpc_call_element *elem = (grpc_call_element *)user_data;
   call_data *calld = elem->call_data;
-  channel_data *chand = elem->channel_data;
   grpc_transport_stream_op *op = &calld->op;
   grpc_metadata_batch *mdb;
   size_t i;
-  reset_service_url(calld);
+  reset_auth_metadata_context(&calld->auth_md_context);
   if (status != GRPC_CREDENTIALS_OK) {
     bubble_up_error(exec_ctx, elem, GRPC_STATUS_UNAUTHENTICATED,
                     "Credentials failed to get metadata.");
@@ -111,15 +116,20 @@ static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *user_data,
   for (i = 0; i < num_md; i++) {
     grpc_metadata_batch_add_tail(
         mdb, &calld->md_links[i],
-        grpc_mdelem_from_slices(chand->md_ctx, gpr_slice_ref(md_elems[i].key),
+        grpc_mdelem_from_slices(gpr_slice_ref(md_elems[i].key),
                                 gpr_slice_ref(md_elems[i].value)));
   }
   grpc_call_next_op(exec_ctx, elem, op);
 }
 
-void build_service_url(const char *url_scheme, call_data *calld) {
+void build_auth_metadata_context(grpc_security_connector *sc,
+                                 grpc_auth_context *auth_context,
+                                 call_data *calld) {
   char *service = gpr_strdup(grpc_mdstr_as_c_string(calld->method));
   char *last_slash = strrchr(service, '/');
+  char *method_name = NULL;
+  char *service_url = NULL;
+  reset_auth_metadata_context(&calld->auth_md_context);
   if (last_slash == NULL) {
     gpr_log(GPR_ERROR, "No '/' found in fully qualified method name");
     service[0] = '\0';
@@ -128,11 +138,16 @@ void build_service_url(const char *url_scheme, call_data *calld) {
     service[1] = '\0';
   } else {
     *last_slash = '\0';
+    method_name = gpr_strdup(last_slash + 1);
   }
-  if (url_scheme == NULL) url_scheme = "";
-  reset_service_url(calld);
-  gpr_asprintf(&calld->service_url, "%s://%s%s", url_scheme,
+  if (method_name == NULL) method_name = gpr_strdup("");
+  gpr_asprintf(&service_url, "%s://%s%s",
+               sc->url_scheme == NULL ? "" : sc->url_scheme,
                grpc_mdstr_as_c_string(calld->host), service);
+  calld->auth_md_context.service_url = service_url;
+  calld->auth_md_context.method_name = method_name;
+  calld->auth_md_context.channel_auth_context =
+      GRPC_AUTH_CONTEXT_REF(auth_context, "grpc_auth_metadata_context");
   gpr_free(service);
 }
 
@@ -166,12 +181,13 @@ static void send_security_metadata(grpc_exec_ctx *exec_ctx,
         call_creds_has_md ? ctx->creds : channel_call_creds);
   }
 
-  build_service_url(chand->security_connector->base.url_scheme, calld);
+  build_auth_metadata_context(&chand->security_connector->base,
+                              chand->auth_context, calld);
   calld->op = *op; /* Copy op (originates from the caller's stack). */
   GPR_ASSERT(calld->pollset);
-  grpc_call_credentials_get_request_metadata(exec_ctx, calld->creds,
-                                             calld->pollset, calld->service_url,
-                                             on_credentials_metadata, elem);
+  grpc_call_credentials_get_request_metadata(
+      exec_ctx, calld->creds, calld->pollset, calld->auth_md_context,
+      on_credentials_metadata, elem);
 }
 
 static void on_host_checked(grpc_exec_ctx *exec_ctx, void *user_data,
@@ -217,7 +233,7 @@ static void auth_start_transport_op(grpc_exec_ctx *exec_ctx,
     sec_ctx = op->context[GRPC_CONTEXT_SECURITY].value;
     GRPC_AUTH_CONTEXT_UNREF(sec_ctx->auth_context, "client auth filter");
     sec_ctx->auth_context = GRPC_AUTH_CONTEXT_REF(
-        chand->security_connector->base.auth_context, "client_auth_filter");
+        chand->auth_context, "client_auth_filter");
   }
 
   if (op->send_initial_metadata != NULL) {
@@ -225,36 +241,22 @@ static void auth_start_transport_op(grpc_exec_ctx *exec_ctx,
       grpc_mdelem *md = l->md;
       /* Pointer comparison is OK for md_elems created from the same context.
        */
-      if (md->key == chand->authority_string) {
+      if (md->key == GRPC_MDSTR_AUTHORITY) {
         if (calld->host != NULL) GRPC_MDSTR_UNREF(calld->host);
         calld->host = GRPC_MDSTR_REF(md->value);
-      } else if (md->key == chand->path_string) {
+      } else if (md->key == GRPC_MDSTR_PATH) {
         if (calld->method != NULL) GRPC_MDSTR_UNREF(calld->method);
         calld->method = GRPC_MDSTR_REF(md->value);
       }
     }
     if (calld->host != NULL) {
-      grpc_security_status status;
       const char *call_host = grpc_mdstr_as_c_string(calld->host);
       calld->op = *op; /* Copy op (originates from the caller's stack). */
-      status = grpc_channel_security_connector_check_call_host(
-          exec_ctx, chand->security_connector, call_host, on_host_checked,
-          elem);
-      if (status != GRPC_SECURITY_OK) {
-        if (status == GRPC_SECURITY_ERROR) {
-          char *error_msg;
-          gpr_asprintf(&error_msg,
-                       "Invalid host %s set in :authority metadata.",
-                       call_host);
-          bubble_up_error(exec_ctx, elem, GRPC_STATUS_INVALID_ARGUMENT,
-                          error_msg);
-          gpr_free(error_msg);
-        }
-        return; /* early exit */
-      }
+      grpc_channel_security_connector_check_call_host(
+          exec_ctx, chand->security_connector, call_host, chand->auth_context,
+          on_host_checked, elem);
+      return; /* early exit */
     }
-    send_security_metadata(exec_ctx, elem, op);
-    return; /* early exit */
   }
 
   /* pass control down the stack */
@@ -285,7 +287,7 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx,
   if (calld->method != NULL) {
     GRPC_MDSTR_UNREF(calld->method);
   }
-  reset_service_url(calld);
+  reset_auth_metadata_context(&calld->auth_md_context);
 }
 
 /* Constructor for channel_data */
@@ -294,6 +296,9 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
                               grpc_channel_element_args *args) {
   grpc_security_connector *sc =
       grpc_find_security_connector_in_args(args->channel_args);
+  grpc_auth_context *auth_context =
+      grpc_find_auth_context_in_args(args->channel_args);
+
   /* grab pointers to our data from the channel element */
   channel_data *chand = elem->channel_data;
 
@@ -302,17 +307,15 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
      path */
   GPR_ASSERT(!args->is_last);
   GPR_ASSERT(sc != NULL);
+  GPR_ASSERT(auth_context != NULL);
 
   /* initialize members */
   GPR_ASSERT(sc->is_client_side);
   chand->security_connector =
       (grpc_channel_security_connector *)GRPC_SECURITY_CONNECTOR_REF(
           sc, "client_auth_filter");
-  chand->md_ctx = args->metadata_context;
-  chand->authority_string = grpc_mdstr_from_string(chand->md_ctx, ":authority");
-  chand->path_string = grpc_mdstr_from_string(chand->md_ctx, ":path");
-  chand->error_msg_key = grpc_mdstr_from_string(chand->md_ctx, "grpc-message");
-  chand->status_key = grpc_mdstr_from_string(chand->md_ctx, "grpc-status");
+  chand->auth_context =
+      GRPC_AUTH_CONTEXT_REF(auth_context, "client_auth_filter");
 }
 
 /* Destructor for channel data */
@@ -320,21 +323,11 @@ static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                  grpc_channel_element *elem) {
   /* grab pointers to our data from the channel element */
   channel_data *chand = elem->channel_data;
-  grpc_channel_security_connector *ctx = chand->security_connector;
-  if (ctx != NULL)
-    GRPC_SECURITY_CONNECTOR_UNREF(&ctx->base, "client_auth_filter");
-  if (chand->authority_string != NULL) {
-    GRPC_MDSTR_UNREF(chand->authority_string);
-  }
-  if (chand->error_msg_key != NULL) {
-    GRPC_MDSTR_UNREF(chand->error_msg_key);
-  }
-  if (chand->status_key != NULL) {
-    GRPC_MDSTR_UNREF(chand->status_key);
-  }
-  if (chand->path_string != NULL) {
-    GRPC_MDSTR_UNREF(chand->path_string);
+  grpc_channel_security_connector *sc = chand->security_connector;
+  if (sc != NULL) {
+    GRPC_SECURITY_CONNECTOR_UNREF(&sc->base, "client_auth_filter");
   }
+  GRPC_AUTH_CONTEXT_UNREF(chand->auth_context, "client_auth_filter");
 }
 
 const grpc_channel_filter grpc_client_auth_filter = {

src/core/security/credentials.c

@@ -33,22 +33,21 @@
 
 #include "src/core/security/credentials.h"
 
-#include <string.h>
 #include <stdio.h>
+#include <string.h>
 
 #include "src/core/channel/channel_args.h"
 #include "src/core/channel/http_client_filter.h"
-#include "src/core/json/json.h"
 #include "src/core/httpcli/httpcli.h"
-#include "src/core/iomgr/iomgr.h"
-#include "src/core/surface/api_trace.h"
+#include "src/core/iomgr/executor.h"
+#include "src/core/json/json.h"
 #include "src/core/support/string.h"
+#include "src/core/surface/api_trace.h"
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 #include <grpc/support/sync.h>
-#include <grpc/support/thd.h>
 #include <grpc/support/time.h>
 
 /* -- Common. -- */
@@ -116,19 +115,17 @@ void grpc_call_credentials_release(grpc_call_credentials *creds) {
   grpc_call_credentials_unref(creds);
 }
 
-void grpc_call_credentials_get_request_metadata(grpc_exec_ctx *exec_ctx,
-                                                grpc_call_credentials *creds,
-                                                grpc_pollset *pollset,
-                                                const char *service_url,
-                                                grpc_credentials_metadata_cb cb,
-                                                void *user_data) {
+void grpc_call_credentials_get_request_metadata(
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
+    grpc_pollset *pollset, grpc_auth_metadata_context context,
+    grpc_credentials_metadata_cb cb, void *user_data) {
   if (creds == NULL || creds->vtable->get_request_metadata == NULL) {
     if (cb != NULL) {
       cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_OK);
     }
     return;
   }
-  creds->vtable->get_request_metadata(exec_ctx, creds, pollset, service_url, cb,
+  creds->vtable->get_request_metadata(exec_ctx, creds, pollset, context, cb,
                                       user_data);
 }
 
@@ -182,8 +179,8 @@ void grpc_server_credentials_set_auth_metadata_processor(
   GRPC_API_TRACE(
       "grpc_server_credentials_set_auth_metadata_processor("
       "creds=%p, "
-      "processor=grpc_auth_metadata_processor { process: %lx, state: %p })",
-      3, (creds, (unsigned long)processor.process, processor.state));
+      "processor=grpc_auth_metadata_processor { process: %p, state: %p })",
+      3, (creds, (void*)(gpr_intptr)processor.process, processor.state));
   if (creds == NULL) return;
   if (creds->processor.destroy != NULL && creds->processor.state != NULL) {
     creds->processor.destroy(creds->processor.state);
@@ -429,7 +426,7 @@ static void jwt_destruct(grpc_call_credentials *creds) {
 static void jwt_get_request_metadata(grpc_exec_ctx *exec_ctx,
                                      grpc_call_credentials *creds,
                                      grpc_pollset *pollset,
-                                     const char *service_url,
+                                     grpc_auth_metadata_context context,
                                      grpc_credentials_metadata_cb cb,
                                      void *user_data) {
   grpc_service_account_jwt_access_credentials *c =
@@ -442,7 +439,7 @@ static void jwt_get_request_metadata(grpc_exec_ctx *exec_ctx,
   {
     gpr_mu_lock(&c->cache_mu);
     if (c->cached.service_url != NULL &&
-        strcmp(c->cached.service_url, service_url) == 0 &&
+        strcmp(c->cached.service_url, context.service_url) == 0 &&
         c->cached.jwt_md != NULL &&
         (gpr_time_cmp(gpr_time_sub(c->cached.jwt_expiration,
                                    gpr_now(GPR_CLOCK_REALTIME)),
@@ -457,14 +454,15 @@ static void jwt_get_request_metadata(grpc_exec_ctx *exec_ctx,
     /* Generate a new jwt. */
     gpr_mu_lock(&c->cache_mu);
     jwt_reset_cache(c);
-    jwt = grpc_jwt_encode_and_sign(&c->key, service_url, c->jwt_lifetime, NULL);
+    jwt = grpc_jwt_encode_and_sign(&c->key, context.service_url,
+                                   c->jwt_lifetime, NULL);
     if (jwt != NULL) {
       char *md_value;
       gpr_asprintf(&md_value, "Bearer %s", jwt);
       gpr_free(jwt);
       c->cached.jwt_expiration =
           gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), c->jwt_lifetime);
-      c->cached.service_url = gpr_strdup(service_url);
+      c->cached.service_url = gpr_strdup(context.service_url);
       c->cached.jwt_md = grpc_credentials_md_store_create(1);
       grpc_credentials_md_store_add_cstrings(
           c->cached.jwt_md, GRPC_AUTHORIZATION_METADATA_KEY, md_value);
@@ -512,10 +510,11 @@ grpc_call_credentials *grpc_service_account_jwt_access_credentials_create(
       "grpc_service_account_jwt_access_credentials_create("
       "json_key=%s, "
       "token_lifetime="
-      "gpr_timespec { tv_sec: %ld, tv_nsec: %d, clock_type: %d }, "
+      "gpr_timespec { tv_sec: %lld, tv_nsec: %d, clock_type: %d }, "
       "reserved=%p)",
-      5, (json_key, (long)token_lifetime.tv_sec, token_lifetime.tv_nsec,
-          (int)token_lifetime.clock_type, reserved));
+      5,
+      (json_key, (long long)token_lifetime.tv_sec, (int)token_lifetime.tv_nsec,
+       (int)token_lifetime.clock_type, reserved));
   GPR_ASSERT(reserved == NULL);
   return grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
       grpc_auth_json_key_create_from_string(json_key), token_lifetime);
@@ -649,7 +648,7 @@ static void on_oauth2_token_fetcher_http_response(
 
 static void oauth2_token_fetcher_get_request_metadata(
     grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
-    grpc_pollset *pollset, const char *service_url,
+    grpc_pollset *pollset, grpc_auth_metadata_context context,
     grpc_credentials_metadata_cb cb, void *user_data) {
   grpc_oauth2_token_fetcher_credentials *c =
       (grpc_oauth2_token_fetcher_credentials *)creds;
@@ -793,30 +792,27 @@ static void md_only_test_destruct(grpc_call_credentials *creds) {
   grpc_credentials_md_store_unref(c->md_store);
 }
 
-static void on_simulated_token_fetch_done(void *user_data) {
+static void on_simulated_token_fetch_done(grpc_exec_ctx *exec_ctx,
+                                          void *user_data, int success) {
   grpc_credentials_metadata_request *r =
       (grpc_credentials_metadata_request *)user_data;
   grpc_md_only_test_credentials *c = (grpc_md_only_test_credentials *)r->creds;
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  r->cb(&exec_ctx, r->user_data, c->md_store->entries, c->md_store->num_entries,
+  r->cb(exec_ctx, r->user_data, c->md_store->entries, c->md_store->num_entries,
         GRPC_CREDENTIALS_OK);
   grpc_credentials_metadata_request_destroy(r);
-  grpc_exec_ctx_finish(&exec_ctx);
 }
 
-static void md_only_test_get_request_metadata(grpc_exec_ctx *exec_ctx,
-                                              grpc_call_credentials *creds,
-                                              grpc_pollset *pollset,
-                                              const char *service_url,
-                                              grpc_credentials_metadata_cb cb,
-                                              void *user_data) {
+static void md_only_test_get_request_metadata(
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
+    grpc_pollset *pollset, grpc_auth_metadata_context context,
+    grpc_credentials_metadata_cb cb, void *user_data) {
   grpc_md_only_test_credentials *c = (grpc_md_only_test_credentials *)creds;
 
   if (c->is_async) {
-    gpr_thd_id thd_id;
     grpc_credentials_metadata_request *cb_arg =
         grpc_credentials_metadata_request_create(creds, cb, user_data);
-    gpr_thd_new(&thd_id, on_simulated_token_fetch_done, cb_arg, NULL);
+    grpc_executor_enqueue(
+        grpc_closure_create(on_simulated_token_fetch_done, cb_arg), 1);
   } else {
     cb(exec_ctx, user_data, c->md_store->entries, 1, GRPC_CREDENTIALS_OK);
   }
@@ -846,12 +842,10 @@ static void access_token_destruct(grpc_call_credentials *creds) {
   grpc_credentials_md_store_unref(c->access_token_md);
 }
 
-static void access_token_get_request_metadata(grpc_exec_ctx *exec_ctx,
-                                              grpc_call_credentials *creds,
-                                              grpc_pollset *pollset,
-                                              const char *service_url,
-                                              grpc_credentials_metadata_cb cb,
-                                              void *user_data) {
+static void access_token_get_request_metadata(
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
+    grpc_pollset *pollset, grpc_auth_metadata_context context,
+    grpc_credentials_metadata_cb cb, void *user_data) {
   grpc_access_token_credentials *c = (grpc_access_token_credentials *)creds;
   cb(exec_ctx, user_data, c->access_token_md->entries, 1, GRPC_CREDENTIALS_OK);
 }
@@ -887,7 +881,7 @@ static grpc_security_status fake_transport_security_create_security_connector(
     grpc_channel_credentials *c, grpc_call_credentials *call_creds,
     const char *target, const grpc_channel_args *args,
     grpc_channel_security_connector **sc, grpc_channel_args **new_args) {
-  *sc = grpc_fake_channel_security_connector_create(call_creds, 1);
+  *sc = grpc_fake_channel_security_connector_create(call_creds);
   return GRPC_SECURITY_OK;
 }
 
@@ -932,7 +926,7 @@ typedef struct {
   grpc_composite_call_credentials *composite_creds;
   size_t creds_index;
   grpc_credentials_md_store *md_elems;
-  char *service_url;
+  grpc_auth_metadata_context auth_md_context;
   void *user_data;
   grpc_pollset *pollset;
   grpc_credentials_metadata_cb cb;
@@ -950,7 +944,6 @@ static void composite_call_destruct(grpc_call_credentials *creds) {
 static void composite_call_md_context_destroy(
     grpc_composite_call_credentials_metadata_context *ctx) {
   grpc_credentials_md_store_unref(ctx->md_elems);
-  if (ctx->service_url != NULL) gpr_free(ctx->service_url);
   gpr_free(ctx);
 }
 
@@ -978,9 +971,9 @@ static void composite_call_metadata_cb(grpc_exec_ctx *exec_ctx, void *user_data,
   if (ctx->creds_index < ctx->composite_creds->inner.num_creds) {
     grpc_call_credentials *inner_creds =
         ctx->composite_creds->inner.creds_array[ctx->creds_index++];
-    grpc_call_credentials_get_request_metadata(exec_ctx, inner_creds,
-                                               ctx->pollset, ctx->service_url,
-                                               composite_call_metadata_cb, ctx);
+    grpc_call_credentials_get_request_metadata(
+        exec_ctx, inner_creds, ctx->pollset, ctx->auth_md_context,
+        composite_call_metadata_cb, ctx);
     return;
   }
 
@@ -990,26 +983,24 @@ static void composite_call_metadata_cb(grpc_exec_ctx *exec_ctx, void *user_data,
   composite_call_md_context_destroy(ctx);
 }
 
-static void composite_call_get_request_metadata(grpc_exec_ctx *exec_ctx,
-                                                grpc_call_credentials *creds,
-                                                grpc_pollset *pollset,
-                                                const char *service_url,
-                                                grpc_credentials_metadata_cb cb,
-                                                void *user_data) {
+static void composite_call_get_request_metadata(
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
+    grpc_pollset *pollset, grpc_auth_metadata_context auth_md_context,
+    grpc_credentials_metadata_cb cb, void *user_data) {
   grpc_composite_call_credentials *c = (grpc_composite_call_credentials *)creds;
   grpc_composite_call_credentials_metadata_context *ctx;
 
   ctx = gpr_malloc(sizeof(grpc_composite_call_credentials_metadata_context));
   memset(ctx, 0, sizeof(grpc_composite_call_credentials_metadata_context));
-  ctx->service_url = gpr_strdup(service_url);
+  ctx->auth_md_context = auth_md_context;
   ctx->user_data = user_data;
   ctx->cb = cb;
   ctx->composite_creds = c;
   ctx->pollset = pollset;
   ctx->md_elems = grpc_credentials_md_store_create(c->inner.num_creds);
   grpc_call_credentials_get_request_metadata(
-      exec_ctx, c->inner.creds_array[ctx->creds_index++], pollset, service_url,
-      composite_call_metadata_cb, ctx);
+      exec_ctx, c->inner.creds_array[ctx->creds_index++], pollset,
+      auth_md_context, composite_call_metadata_cb, ctx);
 }
 
 static grpc_call_credentials_vtable composite_call_credentials_vtable = {
@@ -1103,7 +1094,7 @@ static void iam_destruct(grpc_call_credentials *creds) {
 static void iam_get_request_metadata(grpc_exec_ctx *exec_ctx,
                                      grpc_call_credentials *creds,
                                      grpc_pollset *pollset,
-                                     const char *service_url,
+                                     grpc_auth_metadata_context context,
                                      grpc_credentials_metadata_cb cb,
                                      void *user_data) {
   grpc_google_iam_credentials *c = (grpc_google_iam_credentials *)creds;
@@ -1192,7 +1183,7 @@ static void plugin_md_request_metadata_ready(void *request,
 static void plugin_get_request_metadata(grpc_exec_ctx *exec_ctx,
                                         grpc_call_credentials *creds,
                                         grpc_pollset *pollset,
-                                        const char *service_url,
+                                        grpc_auth_metadata_context context,
                                         grpc_credentials_metadata_cb cb,
                                         void *user_data) {
   grpc_plugin_credentials *c = (grpc_plugin_credentials *)creds;
@@ -1201,7 +1192,7 @@ static void plugin_get_request_metadata(grpc_exec_ctx *exec_ctx,
     memset(request, 0, sizeof(*request));
     request->user_data = user_data;
     request->cb = cb;
-    c->plugin.get_metadata(c->plugin.state, service_url,
+    c->plugin.get_metadata(c->plugin.state, context,
                            plugin_md_request_metadata_ready, request);
   } else {
     cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_OK);
@@ -1218,7 +1209,7 @@ grpc_call_credentials *grpc_metadata_credentials_create_from_plugin(
                  (reserved));
   GPR_ASSERT(reserved == NULL);
   memset(c, 0, sizeof(*c));
-  c->base.type = GRPC_CALL_CREDENTIALS_TYPE_METADATA_PLUGIN;
+  c->base.type = plugin.type;
   c->base.vtable = &plugin_vtable;
   gpr_ref_init(&c->base.refcount, 1);
   c->plugin = plugin;

src/core/security/credentials.h

@@ -59,7 +59,6 @@ typedef enum {
   "FakeTransportSecurity"
 
 #define GRPC_CALL_CREDENTIALS_TYPE_OAUTH2 "Oauth2"
-#define GRPC_CALL_CREDENTIALS_TYPE_METADATA_PLUGIN "Plugin"
 #define GRPC_CALL_CREDENTIALS_TYPE_JWT "Jwt"
 #define GRPC_CALL_CREDENTIALS_TYPE_IAM "Iam"
 #define GRPC_CALL_CREDENTIALS_TYPE_COMPOSITE "Composite"
@@ -94,6 +93,14 @@ typedef enum {
 /* It is the caller's responsibility to gpr_free the result if not NULL. */
 char *grpc_get_well_known_google_credentials_file_path(void);
 
+/* Implementation function for the different platforms. */
+char *grpc_get_well_known_google_credentials_file_path_impl(void);
+
+/* Override for testing only. Not thread-safe */
+typedef char *(*grpc_well_known_credentials_path_getter)(void);
+void grpc_override_well_known_credentials_path_getter(
+    grpc_well_known_credentials_path_getter getter);
+
 /* --- grpc_channel_credentials. --- */
 
 typedef struct {
@@ -162,7 +169,7 @@ typedef struct {
   void (*destruct)(grpc_call_credentials *c);
   void (*get_request_metadata)(grpc_exec_ctx *exec_ctx,
                                grpc_call_credentials *c, grpc_pollset *pollset,
-                               const char *service_url,
+                               grpc_auth_metadata_context context,
                                grpc_credentials_metadata_cb cb,
                                void *user_data);
 } grpc_call_credentials_vtable;
@@ -175,12 +182,10 @@ struct grpc_call_credentials {
 
 grpc_call_credentials *grpc_call_credentials_ref(grpc_call_credentials *creds);
 void grpc_call_credentials_unref(grpc_call_credentials *creds);
-void grpc_call_credentials_get_request_metadata(grpc_exec_ctx *exec_ctx,
-                                                grpc_call_credentials *creds,
-                                                grpc_pollset *pollset,
-                                                const char *service_url,
-                                                grpc_credentials_metadata_cb cb,
-                                                void *user_data);
+void grpc_call_credentials_get_request_metadata(
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
+    grpc_pollset *pollset, grpc_auth_metadata_context context,
+    grpc_credentials_metadata_cb cb, void *user_data);
 
 typedef struct {
   grpc_call_credentials **creds_array;
@@ -204,6 +209,7 @@ grpc_credentials_status
 grpc_oauth2_token_fetcher_credentials_parse_server_response(
     const struct grpc_httpcli_response *response,
     grpc_credentials_md_store **token_md, gpr_timespec *token_lifetime);
+
 void grpc_flush_cached_google_default_credentials(void);
 
 /* Metadata-only credentials with the specified key and value where

src/core/security/credentials_posix.c

@@ -44,7 +44,7 @@
 #include "src/core/support/env.h"
 #include "src/core/support/string.h"
 
-char *grpc_get_well_known_google_credentials_file_path(void) {
+char *grpc_get_well_known_google_credentials_file_path_impl(void) {
   char *result = NULL;
   char *home = gpr_getenv("HOME");
   if (home == NULL) {

src/core/security/credentials_win32.c

@@ -44,7 +44,7 @@
 #include "src/core/support/env.h"
 #include "src/core/support/string.h"
 
-char *grpc_get_well_known_google_credentials_file_path(void) {
+char *grpc_get_well_known_google_credentials_file_path_impl(void) {
   char *result = NULL;
   char *appdata_path = gpr_getenv("APPDATA");
   if (appdata_path == NULL) {

src/core/security/google_default_credentials.c

@@ -241,5 +241,20 @@ void grpc_flush_cached_google_default_credentials(void) {
     grpc_channel_credentials_unref(default_credentials);
     default_credentials = NULL;
   }
+  compute_engine_detection_done = 0;
   gpr_mu_unlock(&g_mu);
 }
+
+/* -- Well known credentials path. -- */
+
+static grpc_well_known_credentials_path_getter creds_path_getter = NULL;
+
+char *grpc_get_well_known_google_credentials_file_path(void) {
+  if (creds_path_getter != NULL) return creds_path_getter();
+  return grpc_get_well_known_google_credentials_file_path_impl();
+}
+
+void grpc_override_well_known_credentials_path_getter(
+    grpc_well_known_credentials_path_getter getter) {
+  creds_path_getter = getter;
+}

src/core/security/handshake.c

@@ -35,6 +35,7 @@
 
 #include <string.h>
 
+#include "src/core/security/security_context.h"
 #include "src/core/security/secure_endpoint.h"
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
@@ -56,6 +57,7 @@ typedef struct {
   void *user_data;
   grpc_closure on_handshake_data_sent_to_peer;
   grpc_closure on_handshake_data_received_from_peer;
+  grpc_auth_context *auth_context;
 } grpc_security_handshake;
 
 static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
@@ -64,12 +66,40 @@ static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
 static void on_handshake_data_sent_to_peer(grpc_exec_ctx *exec_ctx, void *setup,
                                            int success);
 
+static void security_connector_remove_handshake(grpc_security_handshake *h) {
+  grpc_security_connector_handshake_list *node;
+  grpc_security_connector_handshake_list *tmp;
+  grpc_security_connector *sc = h->connector;
+  gpr_mu_lock(&sc->mu);
+  node = sc->handshaking_handshakes;
+  if (node && node->handshake == h) {
+    sc->handshaking_handshakes = node->next;
+    gpr_free(node);
+    gpr_mu_unlock(&sc->mu);
+    return;
+  }
+  while (node) {
+    if (node->next->handshake == h) {
+      tmp = node->next;
+      node->next = node->next->next;
+      gpr_free(tmp);
+      gpr_mu_unlock(&sc->mu);
+      return;
+    }
+    node = node->next;
+  }
+  gpr_mu_unlock(&sc->mu);
+}
+
 static void security_handshake_done(grpc_exec_ctx *exec_ctx,
                                     grpc_security_handshake *h,
                                     int is_success) {
+  if (!h->connector->is_client_side) {
+    security_connector_remove_handshake(h);
+  }
   if (is_success) {
-    h->cb(exec_ctx, h->user_data, GRPC_SECURITY_OK, h->wrapped_endpoint,
-          h->secure_endpoint);
+    h->cb(exec_ctx, h->user_data, GRPC_SECURITY_OK, h->secure_endpoint,
+          h->auth_context);
   } else {
     if (h->secure_endpoint != NULL) {
       grpc_endpoint_shutdown(exec_ctx, h->secure_endpoint);
@@ -77,20 +107,21 @@ static void security_handshake_done(grpc_exec_ctx *exec_ctx,
     } else {
       grpc_endpoint_destroy(exec_ctx, h->wrapped_endpoint);
     }
-    h->cb(exec_ctx, h->user_data, GRPC_SECURITY_ERROR, h->wrapped_endpoint,
-          NULL);
+    h->cb(exec_ctx, h->user_data, GRPC_SECURITY_ERROR, NULL, NULL);
   }
   if (h->handshaker != NULL) tsi_handshaker_destroy(h->handshaker);
   if (h->handshake_buffer != NULL) gpr_free(h->handshake_buffer);
   gpr_slice_buffer_destroy(&h->left_overs);
   gpr_slice_buffer_destroy(&h->outgoing);
   gpr_slice_buffer_destroy(&h->incoming);
+  GRPC_AUTH_CONTEXT_UNREF(h->auth_context, "handshake");
   GRPC_SECURITY_CONNECTOR_UNREF(h->connector, "handshake");
   gpr_free(h);
 }
 
 static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *user_data,
-                            grpc_security_status status) {
+                            grpc_security_status status,
+                            grpc_auth_context *auth_context) {
   grpc_security_handshake *h = user_data;
   tsi_frame_protector *protector;
   tsi_result result;
@@ -99,6 +130,7 @@ static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *user_data,
     security_handshake_done(exec_ctx, h, 0);
     return;
   }
+  h->auth_context = GRPC_AUTH_CONTEXT_REF(auth_context, "handshake");
   result =
       tsi_handshaker_create_frame_protector(h->handshaker, NULL, &protector);
   if (result != TSI_OK) {
@@ -117,7 +149,6 @@ static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *user_data,
 }
 
 static void check_peer(grpc_exec_ctx *exec_ctx, grpc_security_handshake *h) {
-  grpc_security_status peer_status;
   tsi_peer peer;
   tsi_result result = tsi_handshaker_extract_peer(h->handshaker, &peer);
 
@@ -127,15 +158,8 @@ static void check_peer(grpc_exec_ctx *exec_ctx, grpc_security_handshake *h) {
     security_handshake_done(exec_ctx, h, 0);
     return;
   }
-  peer_status = grpc_security_connector_check_peer(h->connector, peer,
-                                                   on_peer_checked, h);
-  if (peer_status == GRPC_SECURITY_ERROR) {
-    gpr_log(GPR_ERROR, "Peer check failed.");
-    security_handshake_done(exec_ctx, h, 0);
-    return;
-  } else if (peer_status == GRPC_SECURITY_OK) {
-    on_peer_checked(exec_ctx, h, peer_status);
-  }
+  grpc_security_connector_check_peer(exec_ctx, h->connector, peer,
+                                     on_peer_checked, h);
 }
 
 static void send_handshake_bytes_to_peer(grpc_exec_ctx *exec_ctx,
@@ -268,6 +292,7 @@ void grpc_do_security_handshake(grpc_exec_ctx *exec_ctx,
                                 grpc_endpoint *nonsecure_endpoint,
                                 grpc_security_handshake_done_cb cb,
                                 void *user_data) {
+  grpc_security_connector_handshake_list *handshake_node;
   grpc_security_handshake *h = gpr_malloc(sizeof(grpc_security_handshake));
   memset(h, 0, sizeof(grpc_security_handshake));
   h->handshaker = handshaker;
@@ -284,5 +309,19 @@ void grpc_do_security_handshake(grpc_exec_ctx *exec_ctx,
   gpr_slice_buffer_init(&h->left_overs);
   gpr_slice_buffer_init(&h->outgoing);
   gpr_slice_buffer_init(&h->incoming);
+  if (!connector->is_client_side) {
+    handshake_node = gpr_malloc(sizeof(grpc_security_connector_handshake_list));
+    handshake_node->handshake = h;
+    gpr_mu_lock(&connector->mu);
+    handshake_node->next = connector->handshaking_handshakes;
+    connector->handshaking_handshakes = handshake_node;
+    gpr_mu_unlock(&connector->mu);
+  }
   send_handshake_bytes_to_peer(exec_ctx, h);
 }
+
+void grpc_security_handshake_shutdown(grpc_exec_ctx *exec_ctx,
+                                      void *handshake) {
+  grpc_security_handshake *h = handshake;
+  grpc_endpoint_shutdown(exec_ctx, h->wrapped_endpoint);
+}

src/core/security/handshake.h

@@ -45,4 +45,6 @@ void grpc_do_security_handshake(grpc_exec_ctx *exec_ctx,
                                 grpc_security_handshake_done_cb cb,
                                 void *user_data);
 
+void grpc_security_handshake_shutdown(grpc_exec_ctx *exec_ctx, void *handshake);
+
 #endif /* GRPC_INTERNAL_CORE_SECURITY_HANDSHAKE_H */