Merge pull request #17459 from grpc/revert-17450-revert-17343-server_address_list

Revert "Revert "Allow encoding arbitrary channel args on a per-address basis.""

BUILD

@@ -1048,7 +1048,6 @@ grpc_cc_library(
         "src/core/ext/filters/client_channel/http_connect_handshaker.cc",
         "src/core/ext/filters/client_channel/http_proxy.cc",
         "src/core/ext/filters/client_channel/lb_policy.cc",
-        "src/core/ext/filters/client_channel/lb_policy_factory.cc",
         "src/core/ext/filters/client_channel/lb_policy_registry.cc",
         "src/core/ext/filters/client_channel/parse_address.cc",
         "src/core/ext/filters/client_channel/proxy_mapper.cc",
@@ -1057,6 +1056,7 @@ grpc_cc_library(
         "src/core/ext/filters/client_channel/resolver_registry.cc",
         "src/core/ext/filters/client_channel/resolver_result_parsing.cc",
         "src/core/ext/filters/client_channel/retry_throttle.cc",
+        "src/core/ext/filters/client_channel/server_address.cc",
         "src/core/ext/filters/client_channel/subchannel.cc",
         "src/core/ext/filters/client_channel/subchannel_index.cc",
     ],
@@ -1080,6 +1080,7 @@ grpc_cc_library(
         "src/core/ext/filters/client_channel/resolver_registry.h",
         "src/core/ext/filters/client_channel/resolver_result_parsing.h",
         "src/core/ext/filters/client_channel/retry_throttle.h",
+        "src/core/ext/filters/client_channel/server_address.h",
         "src/core/ext/filters/client_channel/subchannel.h",
         "src/core/ext/filters/client_channel/subchannel_index.h",
     ],

CMakeLists.txt

@@ -1240,7 +1240,6 @@ add_library(grpc
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
-  src/core/ext/filters/client_channel/lb_policy_factory.cc
   src/core/ext/filters/client_channel/lb_policy_registry.cc
   src/core/ext/filters/client_channel/parse_address.cc
   src/core/ext/filters/client_channel/proxy_mapper.cc
@@ -1249,6 +1248,7 @@ add_library(grpc
   src/core/ext/filters/client_channel/resolver_registry.cc
   src/core/ext/filters/client_channel/resolver_result_parsing.cc
   src/core/ext/filters/client_channel/retry_throttle.cc
+  src/core/ext/filters/client_channel/server_address.cc
   src/core/ext/filters/client_channel/subchannel.cc
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/deadline/deadline_filter.cc
@@ -1592,7 +1592,6 @@ add_library(grpc_cronet
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
-  src/core/ext/filters/client_channel/lb_policy_factory.cc
   src/core/ext/filters/client_channel/lb_policy_registry.cc
   src/core/ext/filters/client_channel/parse_address.cc
   src/core/ext/filters/client_channel/proxy_mapper.cc
@@ -1601,6 +1600,7 @@ add_library(grpc_cronet
   src/core/ext/filters/client_channel/resolver_registry.cc
   src/core/ext/filters/client_channel/resolver_result_parsing.cc
   src/core/ext/filters/client_channel/retry_throttle.cc
+  src/core/ext/filters/client_channel/server_address.cc
   src/core/ext/filters/client_channel/subchannel.cc
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/deadline/deadline_filter.cc
@@ -1963,7 +1963,6 @@ add_library(grpc_test_util
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
-  src/core/ext/filters/client_channel/lb_policy_factory.cc
   src/core/ext/filters/client_channel/lb_policy_registry.cc
   src/core/ext/filters/client_channel/parse_address.cc
   src/core/ext/filters/client_channel/proxy_mapper.cc
@@ -1972,6 +1971,7 @@ add_library(grpc_test_util
   src/core/ext/filters/client_channel/resolver_registry.cc
   src/core/ext/filters/client_channel/resolver_result_parsing.cc
   src/core/ext/filters/client_channel/retry_throttle.cc
+  src/core/ext/filters/client_channel/server_address.cc
   src/core/ext/filters/client_channel/subchannel.cc
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/deadline/deadline_filter.cc
@@ -2283,7 +2283,6 @@ add_library(grpc_test_util_unsecure
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
-  src/core/ext/filters/client_channel/lb_policy_factory.cc
   src/core/ext/filters/client_channel/lb_policy_registry.cc
   src/core/ext/filters/client_channel/parse_address.cc
   src/core/ext/filters/client_channel/proxy_mapper.cc
@@ -2292,6 +2291,7 @@ add_library(grpc_test_util_unsecure
   src/core/ext/filters/client_channel/resolver_registry.cc
   src/core/ext/filters/client_channel/resolver_result_parsing.cc
   src/core/ext/filters/client_channel/retry_throttle.cc
+  src/core/ext/filters/client_channel/server_address.cc
   src/core/ext/filters/client_channel/subchannel.cc
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/deadline/deadline_filter.cc
@@ -2617,7 +2617,6 @@ add_library(grpc_unsecure
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
-  src/core/ext/filters/client_channel/lb_policy_factory.cc
   src/core/ext/filters/client_channel/lb_policy_registry.cc
   src/core/ext/filters/client_channel/parse_address.cc
   src/core/ext/filters/client_channel/proxy_mapper.cc
@@ -2626,6 +2625,7 @@ add_library(grpc_unsecure
   src/core/ext/filters/client_channel/resolver_registry.cc
   src/core/ext/filters/client_channel/resolver_result_parsing.cc
   src/core/ext/filters/client_channel/retry_throttle.cc
+  src/core/ext/filters/client_channel/server_address.cc
   src/core/ext/filters/client_channel/subchannel.cc
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/deadline/deadline_filter.cc
@@ -3469,7 +3469,6 @@ add_library(grpc++_cronet
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
-  src/core/ext/filters/client_channel/lb_policy_factory.cc
   src/core/ext/filters/client_channel/lb_policy_registry.cc
   src/core/ext/filters/client_channel/parse_address.cc
   src/core/ext/filters/client_channel/proxy_mapper.cc
@@ -3478,6 +3477,7 @@ add_library(grpc++_cronet
   src/core/ext/filters/client_channel/resolver_registry.cc
   src/core/ext/filters/client_channel/resolver_result_parsing.cc
   src/core/ext/filters/client_channel/retry_throttle.cc
+  src/core/ext/filters/client_channel/server_address.cc
   src/core/ext/filters/client_channel/subchannel.cc
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/deadline/deadline_filter.cc

Makefile

@@ -3735,7 +3735,6 @@ LIBGRPC_SRC = \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
-    src/core/ext/filters/client_channel/lb_policy_factory.cc \
     src/core/ext/filters/client_channel/lb_policy_registry.cc \
     src/core/ext/filters/client_channel/parse_address.cc \
     src/core/ext/filters/client_channel/proxy_mapper.cc \
@@ -3744,6 +3743,7 @@ LIBGRPC_SRC = \
     src/core/ext/filters/client_channel/resolver_registry.cc \
     src/core/ext/filters/client_channel/resolver_result_parsing.cc \
     src/core/ext/filters/client_channel/retry_throttle.cc \
+    src/core/ext/filters/client_channel/server_address.cc \
     src/core/ext/filters/client_channel/subchannel.cc \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
@@ -4081,7 +4081,6 @@ LIBGRPC_CRONET_SRC = \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
-    src/core/ext/filters/client_channel/lb_policy_factory.cc \
     src/core/ext/filters/client_channel/lb_policy_registry.cc \
     src/core/ext/filters/client_channel/parse_address.cc \
     src/core/ext/filters/client_channel/proxy_mapper.cc \
@@ -4090,6 +4089,7 @@ LIBGRPC_CRONET_SRC = \
     src/core/ext/filters/client_channel/resolver_registry.cc \
     src/core/ext/filters/client_channel/resolver_result_parsing.cc \
     src/core/ext/filters/client_channel/retry_throttle.cc \
+    src/core/ext/filters/client_channel/server_address.cc \
     src/core/ext/filters/client_channel/subchannel.cc \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
@@ -4445,7 +4445,6 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
-    src/core/ext/filters/client_channel/lb_policy_factory.cc \
     src/core/ext/filters/client_channel/lb_policy_registry.cc \
     src/core/ext/filters/client_channel/parse_address.cc \
     src/core/ext/filters/client_channel/proxy_mapper.cc \
@@ -4454,6 +4453,7 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/ext/filters/client_channel/resolver_registry.cc \
     src/core/ext/filters/client_channel/resolver_result_parsing.cc \
     src/core/ext/filters/client_channel/retry_throttle.cc \
+    src/core/ext/filters/client_channel/server_address.cc \
     src/core/ext/filters/client_channel/subchannel.cc \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
@@ -4751,7 +4751,6 @@ LIBGRPC_TEST_UTIL_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
-    src/core/ext/filters/client_channel/lb_policy_factory.cc \
     src/core/ext/filters/client_channel/lb_policy_registry.cc \
     src/core/ext/filters/client_channel/parse_address.cc \
     src/core/ext/filters/client_channel/proxy_mapper.cc \
@@ -4760,6 +4759,7 @@ LIBGRPC_TEST_UTIL_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/resolver_registry.cc \
     src/core/ext/filters/client_channel/resolver_result_parsing.cc \
     src/core/ext/filters/client_channel/retry_throttle.cc \
+    src/core/ext/filters/client_channel/server_address.cc \
     src/core/ext/filters/client_channel/subchannel.cc \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
@@ -5058,7 +5058,6 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
-    src/core/ext/filters/client_channel/lb_policy_factory.cc \
     src/core/ext/filters/client_channel/lb_policy_registry.cc \
     src/core/ext/filters/client_channel/parse_address.cc \
     src/core/ext/filters/client_channel/proxy_mapper.cc \
@@ -5067,6 +5066,7 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/resolver_registry.cc \
     src/core/ext/filters/client_channel/resolver_result_parsing.cc \
     src/core/ext/filters/client_channel/retry_throttle.cc \
+    src/core/ext/filters/client_channel/server_address.cc \
     src/core/ext/filters/client_channel/subchannel.cc \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
@@ -5885,7 +5885,6 @@ LIBGRPC++_CRONET_SRC = \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
-    src/core/ext/filters/client_channel/lb_policy_factory.cc \
     src/core/ext/filters/client_channel/lb_policy_registry.cc \
     src/core/ext/filters/client_channel/parse_address.cc \
     src/core/ext/filters/client_channel/proxy_mapper.cc \
@@ -5894,6 +5893,7 @@ LIBGRPC++_CRONET_SRC = \
     src/core/ext/filters/client_channel/resolver_registry.cc \
     src/core/ext/filters/client_channel/resolver_result_parsing.cc \
     src/core/ext/filters/client_channel/retry_throttle.cc \
+    src/core/ext/filters/client_channel/server_address.cc \
     src/core/ext/filters/client_channel/subchannel.cc \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \

build.yaml

@@ -589,6 +589,7 @@ filegroups:
   - src/core/ext/filters/client_channel/resolver_registry.h
   - src/core/ext/filters/client_channel/resolver_result_parsing.h
   - src/core/ext/filters/client_channel/retry_throttle.h
+  - src/core/ext/filters/client_channel/server_address.h
   - src/core/ext/filters/client_channel/subchannel.h
   - src/core/ext/filters/client_channel/subchannel_index.h
   src:
@@ -603,7 +604,6 @@ filegroups:
   - src/core/ext/filters/client_channel/http_connect_handshaker.cc
   - src/core/ext/filters/client_channel/http_proxy.cc
   - src/core/ext/filters/client_channel/lb_policy.cc
-  - src/core/ext/filters/client_channel/lb_policy_factory.cc
   - src/core/ext/filters/client_channel/lb_policy_registry.cc
   - src/core/ext/filters/client_channel/parse_address.cc
   - src/core/ext/filters/client_channel/proxy_mapper.cc
@@ -612,6 +612,7 @@ filegroups:
   - src/core/ext/filters/client_channel/resolver_registry.cc
   - src/core/ext/filters/client_channel/resolver_result_parsing.cc
   - src/core/ext/filters/client_channel/retry_throttle.cc
+  - src/core/ext/filters/client_channel/server_address.cc
   - src/core/ext/filters/client_channel/subchannel.cc
   - src/core/ext/filters/client_channel/subchannel_index.cc
   plugin: grpc_client_channel

config.m4

@@ -348,7 +348,6 @@ if test "$PHP_GRPC" != "no"; then
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
-    src/core/ext/filters/client_channel/lb_policy_factory.cc \
     src/core/ext/filters/client_channel/lb_policy_registry.cc \
     src/core/ext/filters/client_channel/parse_address.cc \
     src/core/ext/filters/client_channel/proxy_mapper.cc \
@@ -357,6 +356,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/ext/filters/client_channel/resolver_registry.cc \
     src/core/ext/filters/client_channel/resolver_result_parsing.cc \
     src/core/ext/filters/client_channel/retry_throttle.cc \
+    src/core/ext/filters/client_channel/server_address.cc \
     src/core/ext/filters/client_channel/subchannel.cc \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \

config.w32

@@ -323,7 +323,6 @@ if (PHP_GRPC != "no") {
     "src\\core\\ext\\filters\\client_channel\\http_connect_handshaker.cc " +
     "src\\core\\ext\\filters\\client_channel\\http_proxy.cc " +
     "src\\core\\ext\\filters\\client_channel\\lb_policy.cc " +
-    "src\\core\\ext\\filters\\client_channel\\lb_policy_factory.cc " +
     "src\\core\\ext\\filters\\client_channel\\lb_policy_registry.cc " +
     "src\\core\\ext\\filters\\client_channel\\parse_address.cc " +
     "src\\core\\ext\\filters\\client_channel\\proxy_mapper.cc " +
@@ -332,6 +331,7 @@ if (PHP_GRPC != "no") {
     "src\\core\\ext\\filters\\client_channel\\resolver_registry.cc " +
     "src\\core\\ext\\filters\\client_channel\\resolver_result_parsing.cc " +
     "src\\core\\ext\\filters\\client_channel\\retry_throttle.cc " +
+    "src\\core\\ext\\filters\\client_channel\\server_address.cc " +
     "src\\core\\ext\\filters\\client_channel\\subchannel.cc " +
     "src\\core\\ext\\filters\\client_channel\\subchannel_index.cc " +
     "src\\core\\ext\\filters\\deadline\\deadline_filter.cc " +

gRPC-C++.podspec

@@ -356,6 +356,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/resolver_registry.h',
                       'src/core/ext/filters/client_channel/resolver_result_parsing.h',
                       'src/core/ext/filters/client_channel/retry_throttle.h',
+                      'src/core/ext/filters/client_channel/server_address.h',
                       'src/core/ext/filters/client_channel/subchannel.h',
                       'src/core/ext/filters/client_channel/subchannel_index.h',
                       'src/core/ext/filters/deadline/deadline_filter.h',

gRPC-Core.podspec

@@ -354,6 +354,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/resolver_registry.h',
                       'src/core/ext/filters/client_channel/resolver_result_parsing.h',
                       'src/core/ext/filters/client_channel/retry_throttle.h',
+                      'src/core/ext/filters/client_channel/server_address.h',
                       'src/core/ext/filters/client_channel/subchannel.h',
                       'src/core/ext/filters/client_channel/subchannel_index.h',
                       'src/core/ext/filters/deadline/deadline_filter.h',
@@ -786,7 +787,6 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
                       'src/core/ext/filters/client_channel/http_proxy.cc',
                       'src/core/ext/filters/client_channel/lb_policy.cc',
-                      'src/core/ext/filters/client_channel/lb_policy_factory.cc',
                       'src/core/ext/filters/client_channel/lb_policy_registry.cc',
                       'src/core/ext/filters/client_channel/parse_address.cc',
                       'src/core/ext/filters/client_channel/proxy_mapper.cc',
@@ -795,6 +795,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/resolver_registry.cc',
                       'src/core/ext/filters/client_channel/resolver_result_parsing.cc',
                       'src/core/ext/filters/client_channel/retry_throttle.cc',
+                      'src/core/ext/filters/client_channel/server_address.cc',
                       'src/core/ext/filters/client_channel/subchannel.cc',
                       'src/core/ext/filters/client_channel/subchannel_index.cc',
                       'src/core/ext/filters/deadline/deadline_filter.cc',
@@ -974,6 +975,7 @@ Pod::Spec.new do |s|
                               'src/core/ext/filters/client_channel/resolver_registry.h',
                               'src/core/ext/filters/client_channel/resolver_result_parsing.h',
                               'src/core/ext/filters/client_channel/retry_throttle.h',
+                              'src/core/ext/filters/client_channel/server_address.h',
                               'src/core/ext/filters/client_channel/subchannel.h',
                               'src/core/ext/filters/client_channel/subchannel_index.h',
                               'src/core/ext/filters/deadline/deadline_filter.h',

grpc.gemspec

@@ -290,6 +290,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/filters/client_channel/resolver_registry.h )
   s.files += %w( src/core/ext/filters/client_channel/resolver_result_parsing.h )
   s.files += %w( src/core/ext/filters/client_channel/retry_throttle.h )
+  s.files += %w( src/core/ext/filters/client_channel/server_address.h )
   s.files += %w( src/core/ext/filters/client_channel/subchannel.h )
   s.files += %w( src/core/ext/filters/client_channel/subchannel_index.h )
   s.files += %w( src/core/ext/filters/deadline/deadline_filter.h )
@@ -725,7 +726,6 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/filters/client_channel/http_connect_handshaker.cc )
   s.files += %w( src/core/ext/filters/client_channel/http_proxy.cc )
   s.files += %w( src/core/ext/filters/client_channel/lb_policy.cc )
-  s.files += %w( src/core/ext/filters/client_channel/lb_policy_factory.cc )
   s.files += %w( src/core/ext/filters/client_channel/lb_policy_registry.cc )
   s.files += %w( src/core/ext/filters/client_channel/parse_address.cc )
   s.files += %w( src/core/ext/filters/client_channel/proxy_mapper.cc )
@@ -734,6 +734,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/filters/client_channel/resolver_registry.cc )
   s.files += %w( src/core/ext/filters/client_channel/resolver_result_parsing.cc )
   s.files += %w( src/core/ext/filters/client_channel/retry_throttle.cc )
+  s.files += %w( src/core/ext/filters/client_channel/server_address.cc )
   s.files += %w( src/core/ext/filters/client_channel/subchannel.cc )
   s.files += %w( src/core/ext/filters/client_channel/subchannel_index.cc )
   s.files += %w( src/core/ext/filters/deadline/deadline_filter.cc )

grpc.gyp

@@ -540,7 +540,6 @@
         'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
         'src/core/ext/filters/client_channel/http_proxy.cc',
         'src/core/ext/filters/client_channel/lb_policy.cc',
-        'src/core/ext/filters/client_channel/lb_policy_factory.cc',
         'src/core/ext/filters/client_channel/lb_policy_registry.cc',
         'src/core/ext/filters/client_channel/parse_address.cc',
         'src/core/ext/filters/client_channel/proxy_mapper.cc',
@@ -549,6 +548,7 @@
         'src/core/ext/filters/client_channel/resolver_registry.cc',
         'src/core/ext/filters/client_channel/resolver_result_parsing.cc',
         'src/core/ext/filters/client_channel/retry_throttle.cc',
+        'src/core/ext/filters/client_channel/server_address.cc',
         'src/core/ext/filters/client_channel/subchannel.cc',
         'src/core/ext/filters/client_channel/subchannel_index.cc',
         'src/core/ext/filters/deadline/deadline_filter.cc',
@@ -799,7 +799,6 @@
         'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
         'src/core/ext/filters/client_channel/http_proxy.cc',
         'src/core/ext/filters/client_channel/lb_policy.cc',
-        'src/core/ext/filters/client_channel/lb_policy_factory.cc',
         'src/core/ext/filters/client_channel/lb_policy_registry.cc',
         'src/core/ext/filters/client_channel/parse_address.cc',
         'src/core/ext/filters/client_channel/proxy_mapper.cc',
@@ -808,6 +807,7 @@
         'src/core/ext/filters/client_channel/resolver_registry.cc',
         'src/core/ext/filters/client_channel/resolver_result_parsing.cc',
         'src/core/ext/filters/client_channel/retry_throttle.cc',
+        'src/core/ext/filters/client_channel/server_address.cc',
         'src/core/ext/filters/client_channel/subchannel.cc',
         'src/core/ext/filters/client_channel/subchannel_index.cc',
         'src/core/ext/filters/deadline/deadline_filter.cc',
@@ -1039,7 +1039,6 @@
         'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
         'src/core/ext/filters/client_channel/http_proxy.cc',
         'src/core/ext/filters/client_channel/lb_policy.cc',
-        'src/core/ext/filters/client_channel/lb_policy_factory.cc',
         'src/core/ext/filters/client_channel/lb_policy_registry.cc',
         'src/core/ext/filters/client_channel/parse_address.cc',
         'src/core/ext/filters/client_channel/proxy_mapper.cc',
@@ -1048,6 +1047,7 @@
         'src/core/ext/filters/client_channel/resolver_registry.cc',
         'src/core/ext/filters/client_channel/resolver_result_parsing.cc',
         'src/core/ext/filters/client_channel/retry_throttle.cc',
+        'src/core/ext/filters/client_channel/server_address.cc',
         'src/core/ext/filters/client_channel/subchannel.cc',
         'src/core/ext/filters/client_channel/subchannel_index.cc',
         'src/core/ext/filters/deadline/deadline_filter.cc',
@@ -1292,7 +1292,6 @@
         'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
         'src/core/ext/filters/client_channel/http_proxy.cc',
         'src/core/ext/filters/client_channel/lb_policy.cc',
-        'src/core/ext/filters/client_channel/lb_policy_factory.cc',
         'src/core/ext/filters/client_channel/lb_policy_registry.cc',
         'src/core/ext/filters/client_channel/parse_address.cc',
         'src/core/ext/filters/client_channel/proxy_mapper.cc',
@@ -1301,6 +1300,7 @@
         'src/core/ext/filters/client_channel/resolver_registry.cc',
         'src/core/ext/filters/client_channel/resolver_result_parsing.cc',
         'src/core/ext/filters/client_channel/retry_throttle.cc',
+        'src/core/ext/filters/client_channel/server_address.cc',
         'src/core/ext/filters/client_channel/subchannel.cc',
         'src/core/ext/filters/client_channel/subchannel_index.cc',
         'src/core/ext/filters/deadline/deadline_filter.cc',

package.xml

@@ -295,6 +295,7 @@
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver_registry.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver_result_parsing.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/retry_throttle.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/server_address.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/subchannel.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/subchannel_index.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/deadline/deadline_filter.h" role="src" />
@@ -730,7 +731,6 @@
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/http_connect_handshaker.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/http_proxy.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/lb_policy.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/lb_policy_factory.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/lb_policy_registry.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/parse_address.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/proxy_mapper.cc" role="src" />
@@ -739,6 +739,7 @@
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver_registry.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver_result_parsing.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/retry_throttle.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/server_address.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/subchannel.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/subchannel_index.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/deadline/deadline_filter.cc" role="src" />

src/core/ext/filters/client_channel/client_channel.cc

@@ -38,6 +38,7 @@
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/ext/filters/client_channel/resolver_result_parsing.h"
 #include "src/core/ext/filters/client_channel/retry_throttle.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/ext/filters/client_channel/subchannel.h"
 #include "src/core/ext/filters/deadline/deadline_filter.h"
 #include "src/core/lib/backoff/backoff.h"
@@ -62,6 +63,7 @@
 #include "src/core/lib/transport/static_metadata.h"
 #include "src/core/lib/transport/status_metadata.h"
 
+using grpc_core::ServerAddressList;
 using grpc_core::internal::ClientChannelMethodParams;
 using grpc_core::internal::ClientChannelMethodParamsTable;
 using grpc_core::internal::ProcessedResolverResult;
@@ -383,16 +385,10 @@ static void create_new_lb_policy_locked(
 
 static void maybe_add_trace_message_for_address_changes_locked(
     channel_data* chand, TraceStringVector* trace_strings) {
-  int resolution_contains_addresses = false;
-  const grpc_arg* channel_arg =
-      grpc_channel_args_find(chand->resolver_result, GRPC_ARG_LB_ADDRESSES);
-  if (channel_arg != nullptr && channel_arg->type == GRPC_ARG_POINTER) {
-    grpc_lb_addresses* addresses =
-        static_cast<grpc_lb_addresses*>(channel_arg->value.pointer.p);
-    if (addresses->num_addresses > 0) {
-      resolution_contains_addresses = true;
-    }
-  }
+  const ServerAddressList* addresses =
+      grpc_core::FindServerAddressListChannelArg(chand->resolver_result);
+  const bool resolution_contains_addresses =
+      addresses != nullptr && addresses->size() > 0;
   if (!resolution_contains_addresses &&
       chand->previous_resolution_contained_addresses) {
     trace_strings->push_back(gpr_strdup("Address list became empty"));

src/core/ext/filters/client_channel/lb_policy.h

@@ -55,7 +55,7 @@ class LoadBalancingPolicy : public InternallyRefCounted<LoadBalancingPolicy> {
     grpc_client_channel_factory* client_channel_factory = nullptr;
     /// Channel args from the resolver.
     /// Note that the LB policy gets the set of addresses from the
-    /// GRPC_ARG_LB_ADDRESSES channel arg.
+    /// GRPC_ARG_SERVER_ADDRESS_LIST channel arg.
     grpc_channel_args* args = nullptr;
     /// Load balancing config from the resolver.
     grpc_json* lb_config = nullptr;
@@ -80,11 +80,6 @@ class LoadBalancingPolicy : public InternallyRefCounted<LoadBalancingPolicy> {
     /// Will be populated with context to pass to the subchannel call, if
     /// needed.
     grpc_call_context_element subchannel_call_context[GRPC_CONTEXT_COUNT] = {};
-    /// Upon success, \a *user_data will be set to whatever opaque information
-    /// may need to be propagated from the LB policy, or nullptr if not needed.
-    // TODO(roth): As part of revamping our metadata APIs, try to find a
-    // way to clean this up and C++-ify it.
-    void** user_data = nullptr;
     /// Next pointer.  For internal use by LB policy.
     PickState* next = nullptr;
   };
@@ -95,7 +90,7 @@ class LoadBalancingPolicy : public InternallyRefCounted<LoadBalancingPolicy> {
 
   /// Updates the policy with a new set of \a args and a new \a lb_config from
   /// the resolver. Note that the LB policy gets the set of addresses from the
-  /// GRPC_ARG_LB_ADDRESSES channel arg.
+  /// GRPC_ARG_SERVER_ADDRESS_LIST channel arg.
   virtual void UpdateLocked(const grpc_channel_args& args,
                             grpc_json* lb_config) GRPC_ABSTRACT;
 

src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc

@@ -84,6 +84,7 @@
 #include "src/core/ext/filters/client_channel/lb_policy_registry.h"
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/ext/filters/client_channel/subchannel_index.h"
 #include "src/core/lib/backoff/backoff.h"
 #include "src/core/lib/channel/channel_args.h"
@@ -113,6 +114,8 @@
 #define GRPC_GRPCLB_RECONNECT_JITTER 0.2
 #define GRPC_GRPCLB_DEFAULT_FALLBACK_TIMEOUT_MS 10000
 
+#define GRPC_ARG_GRPCLB_ADDRESS_LB_TOKEN "grpc.grpclb_address_lb_token"
+
 namespace grpc_core {
 
 TraceFlag grpc_lb_glb_trace(false, "glb");
@@ -121,7 +124,7 @@ namespace {
 
 class GrpcLb : public LoadBalancingPolicy {
  public:
-  GrpcLb(const grpc_lb_addresses* addresses, const Args& args);
+  explicit GrpcLb(const Args& args);
 
   void UpdateLocked(const grpc_channel_args& args,
                     grpc_json* lb_config) override;
@@ -161,9 +164,6 @@ class GrpcLb : public LoadBalancingPolicy {
     // Our on_complete closure and the original one.
     grpc_closure on_complete;
     grpc_closure* original_on_complete;
-    // The LB token associated with the pick.  This is set via user_data in
-    // the pick.
-    grpc_mdelem lb_token;
     // Stats for client-side load reporting.
     RefCountedPtr<GrpcLbClientStats> client_stats;
     // Next pending pick.
@@ -329,7 +329,7 @@ class GrpcLb : public LoadBalancingPolicy {
   // 0 means not using fallback.
   int lb_fallback_timeout_ms_ = 0;
   // The backend addresses from the resolver.
-  grpc_lb_addresses* fallback_backend_addresses_ = nullptr;
+  UniquePtr<ServerAddressList> fallback_backend_addresses_;
   // Fallback timer.
   bool fallback_timer_callback_pending_ = false;
   grpc_timer lb_fallback_timer_;
@@ -349,7 +349,7 @@ class GrpcLb : public LoadBalancingPolicy {
 // serverlist parsing code
 //
 
-// vtable for LB tokens in grpc_lb_addresses
+// vtable for LB token channel arg.
 void* lb_token_copy(void* token) {
   return token == nullptr
              ? nullptr
@@ -361,38 +361,11 @@ void lb_token_destroy(void* token) {
   }
 }
 int lb_token_cmp(void* token1, void* token2) {
-  if (token1 > token2) return 1;
-  if (token1 < token2) return -1;
-  return 0;
+  return GPR_ICMP(token1, token2);
 }
-const grpc_lb_user_data_vtable lb_token_vtable = {
+const grpc_arg_pointer_vtable lb_token_arg_vtable = {
     lb_token_copy, lb_token_destroy, lb_token_cmp};
 
-// Returns the backend addresses extracted from the given addresses.
-grpc_lb_addresses* ExtractBackendAddresses(const grpc_lb_addresses* addresses) {
-  // First pass: count the number of backend addresses.
-  size_t num_backends = 0;
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    if (!addresses->addresses[i].is_balancer) {
-      ++num_backends;
-    }
-  }
-  // Second pass: actually populate the addresses and (empty) LB tokens.
-  grpc_lb_addresses* backend_addresses =
-      grpc_lb_addresses_create(num_backends, &lb_token_vtable);
-  size_t num_copied = 0;
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    if (addresses->addresses[i].is_balancer) continue;
-    const grpc_resolved_address* addr = &addresses->addresses[i].address;
-    grpc_lb_addresses_set_address(backend_addresses, num_copied, &addr->addr,
-                                  addr->len, false /* is_balancer */,
-                                  nullptr /* balancer_name */,
-                                  (void*)GRPC_MDELEM_LB_TOKEN_EMPTY.payload);
-    ++num_copied;
-  }
-  return backend_addresses;
-}
-
 bool IsServerValid(const grpc_grpclb_server* server, size_t idx, bool log) {
   if (server->drop) return false;
   const grpc_grpclb_ip_address* ip = &server->ip_address;
@@ -440,30 +413,16 @@ void ParseServer(const grpc_grpclb_server* server,
 }
 
 // Returns addresses extracted from \a serverlist.
-grpc_lb_addresses* ProcessServerlist(const grpc_grpclb_serverlist* serverlist) {
-  size_t num_valid = 0;
-  /* first pass: count how many are valid in order to allocate the necessary
-   * memory in a single block */
+ServerAddressList ProcessServerlist(const grpc_grpclb_serverlist* serverlist) {
+  ServerAddressList addresses;
   for (size_t i = 0; i < serverlist->num_servers; ++i) {
-    if (IsServerValid(serverlist->servers[i], i, true)) ++num_valid;
-  }
-  grpc_lb_addresses* lb_addresses =
-      grpc_lb_addresses_create(num_valid, &lb_token_vtable);
-  /* second pass: actually populate the addresses and LB tokens (aka user data
-   * to the outside world) to be read by the RR policy during its creation.
-   * Given that the validity tests are very cheap, they are performed again
-   * instead of marking the valid ones during the first pass, as this would
-   * incurr in an allocation due to the arbitrary number of server */
-  size_t addr_idx = 0;
-  for (size_t sl_idx = 0; sl_idx < serverlist->num_servers; ++sl_idx) {
-    const grpc_grpclb_server* server = serverlist->servers[sl_idx];
-    if (!IsServerValid(serverlist->servers[sl_idx], sl_idx, false)) continue;
-    GPR_ASSERT(addr_idx < num_valid);
-    /* address processing */
+    const grpc_grpclb_server* server = serverlist->servers[i];
+    if (!IsServerValid(serverlist->servers[i], i, false)) continue;
+    // Address processing.
     grpc_resolved_address addr;
     ParseServer(server, &addr);
-    /* lb token processing */
-    void* user_data;
+    // LB token processing.
+    void* lb_token;
     if (server->has_load_balance_token) {
       const size_t lb_token_max_length =
           GPR_ARRAY_SIZE(server->load_balance_token);
@@ -471,7 +430,7 @@ grpc_lb_addresses* ProcessServerlist(const grpc_grpclb_serverlist* serverlist) {
           strnlen(server->load_balance_token, lb_token_max_length);
       grpc_slice lb_token_mdstr = grpc_slice_from_copied_buffer(
           server->load_balance_token, lb_token_length);
-      user_data =
+      lb_token =
           (void*)grpc_mdelem_from_slices(GRPC_MDSTR_LB_TOKEN, lb_token_mdstr)
               .payload;
     } else {
@@ -481,15 +440,16 @@ grpc_lb_addresses* ProcessServerlist(const grpc_grpclb_serverlist* serverlist) {
               "be used instead",
               uri);
       gpr_free(uri);
-      user_data = (void*)GRPC_MDELEM_LB_TOKEN_EMPTY.payload;
+      lb_token = (void*)GRPC_MDELEM_LB_TOKEN_EMPTY.payload;
     }
-    grpc_lb_addresses_set_address(lb_addresses, addr_idx, &addr.addr, addr.len,
-                                  false /* is_balancer */,
-                                  nullptr /* balancer_name */, user_data);
-    ++addr_idx;
-  }
-  GPR_ASSERT(addr_idx == num_valid);
-  return lb_addresses;
+    // Add address.
+    grpc_arg arg = grpc_channel_arg_pointer_create(
+        const_cast<char*>(GRPC_ARG_GRPCLB_ADDRESS_LB_TOKEN), lb_token,
+        &lb_token_arg_vtable);
+    grpc_channel_args* args = grpc_channel_args_copy_and_add(nullptr, &arg, 1);
+    addresses.emplace_back(addr, args);
+  }
+  return addresses;
 }
 
 //
@@ -829,8 +789,7 @@ void GrpcLb::BalancerCallState::OnBalancerMessageReceivedLocked(
         grpc_grpclb_destroy_serverlist(grpclb_policy->serverlist_);
       } else {
         // Dispose of the fallback.
-        grpc_lb_addresses_destroy(grpclb_policy->fallback_backend_addresses_);
-        grpclb_policy->fallback_backend_addresses_ = nullptr;
+        grpclb_policy->fallback_backend_addresses_.reset();
         if (grpclb_policy->fallback_timer_callback_pending_) {
           grpc_timer_cancel(&grpclb_policy->lb_fallback_timer_);
         }
@@ -910,31 +869,25 @@ void GrpcLb::BalancerCallState::OnBalancerStatusReceivedLocked(
 // helper code for creating balancer channel
 //
 
-grpc_lb_addresses* ExtractBalancerAddresses(
-    const grpc_lb_addresses* addresses) {
-  size_t num_grpclb_addrs = 0;
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    if (addresses->addresses[i].is_balancer) ++num_grpclb_addrs;
-  }
-  // There must be at least one balancer address, or else the
-  // client_channel would not have chosen this LB policy.
-  GPR_ASSERT(num_grpclb_addrs > 0);
-  grpc_lb_addresses* lb_addresses =
-      grpc_lb_addresses_create(num_grpclb_addrs, nullptr);
-  size_t lb_addresses_idx = 0;
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    if (!addresses->addresses[i].is_balancer) continue;
-    if (GPR_UNLIKELY(addresses->addresses[i].user_data != nullptr)) {
-      gpr_log(GPR_ERROR,
-              "This LB policy doesn't support user data. It will be ignored");
+ServerAddressList ExtractBalancerAddresses(const ServerAddressList& addresses) {
+  ServerAddressList balancer_addresses;
+  for (size_t i = 0; i < addresses.size(); ++i) {
+    if (addresses[i].IsBalancer()) {
+      // Strip out the is_balancer channel arg, since we don't want to
+      // recursively use the grpclb policy in the channel used to talk to
+      // the balancers.  Note that we do NOT strip out the balancer_name
+      // channel arg, since we need that to set the authority correctly
+      // to talk to the balancers.
+      static const char* args_to_remove[] = {
+          GRPC_ARG_ADDRESS_IS_BALANCER,
+      };
+      balancer_addresses.emplace_back(
+          addresses[i].address(),
+          grpc_channel_args_copy_and_remove(addresses[i].args(), args_to_remove,
+                                            GPR_ARRAY_SIZE(args_to_remove)));
     }
-    grpc_lb_addresses_set_address(
-        lb_addresses, lb_addresses_idx++, addresses->addresses[i].address.addr,
-        addresses->addresses[i].address.len, false /* is balancer */,
-        addresses->addresses[i].balancer_name, nullptr /* user data */);
   }
-  GPR_ASSERT(num_grpclb_addrs == lb_addresses_idx);
-  return lb_addresses;
+  return balancer_addresses;
 }
 
 /* Returns the channel args for the LB channel, used to create a bidirectional
@@ -946,10 +899,10 @@ grpc_lb_addresses* ExtractBalancerAddresses(
  *   above the grpclb policy.
  *   - \a args: other args inherited from the grpclb policy. */
 grpc_channel_args* BuildBalancerChannelArgs(
-    const grpc_lb_addresses* addresses,
+    const ServerAddressList& addresses,
     FakeResolverResponseGenerator* response_generator,
     const grpc_channel_args* args) {
-  grpc_lb_addresses* lb_addresses = ExtractBalancerAddresses(addresses);
+  ServerAddressList balancer_addresses = ExtractBalancerAddresses(addresses);
   // Channel args to remove.
   static const char* args_to_remove[] = {
       // LB policy name, since we want to use the default (pick_first) in
@@ -967,7 +920,7 @@ grpc_channel_args* BuildBalancerChannelArgs(
       // is_balancer=true.  We need the LB channel to return addresses with
       // is_balancer=false so that it does not wind up recursively using the
       // grpclb LB policy, as per the special case logic in client_channel.c.
-      GRPC_ARG_LB_ADDRESSES,
+      GRPC_ARG_SERVER_ADDRESS_LIST,
       // The fake resolver response generator, because we are replacing it
       // with the one from the grpclb policy, used to propagate updates to
       // the LB channel.
@@ -983,10 +936,10 @@ grpc_channel_args* BuildBalancerChannelArgs(
   };
   // Channel args to add.
   const grpc_arg args_to_add[] = {
-      // New LB addresses.
+      // New address list.
       // Note that we pass these in both when creating the LB channel
       // and via the fake resolver.  The latter is what actually gets used.
-      grpc_lb_addresses_create_channel_arg(lb_addresses),
+      CreateServerAddressListChannelArg(&balancer_addresses),
       // The fake resolver response generator, which we use to inject
       // address updates into the LB channel.
       grpc_core::FakeResolverResponseGenerator::MakeChannelArg(
@@ -1004,18 +957,14 @@ grpc_channel_args* BuildBalancerChannelArgs(
       args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), args_to_add,
       GPR_ARRAY_SIZE(args_to_add));
   // Make any necessary modifications for security.
-  new_args = grpc_lb_policy_grpclb_modify_lb_channel_args(new_args);
-  // Clean up.
-  grpc_lb_addresses_destroy(lb_addresses);
-  return new_args;
+  return grpc_lb_policy_grpclb_modify_lb_channel_args(new_args);
 }
 
 //
 // ctor and dtor
 //
 
-GrpcLb::GrpcLb(const grpc_lb_addresses* addresses,
-               const LoadBalancingPolicy::Args& args)
+GrpcLb::GrpcLb(const LoadBalancingPolicy::Args& args)
     : LoadBalancingPolicy(args),
       response_generator_(MakeRefCounted<FakeResolverResponseGenerator>()),
       lb_call_backoff_(
@@ -1072,9 +1021,6 @@ GrpcLb::~GrpcLb() {
   if (serverlist_ != nullptr) {
     grpc_grpclb_destroy_serverlist(serverlist_);
   }
-  if (fallback_backend_addresses_ != nullptr) {
-    grpc_lb_addresses_destroy(fallback_backend_addresses_);
-  }
   grpc_subchannel_index_unref();
 }
 
@@ -1122,7 +1068,6 @@ void GrpcLb::HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) {
   while ((pp = pending_picks_) != nullptr) {
     pending_picks_ = pp->next;
     pp->pick->on_complete = pp->original_on_complete;
-    pp->pick->user_data = nullptr;
     grpc_error* error = GRPC_ERROR_NONE;
     if (new_policy->PickLocked(pp->pick, &error)) {
       // Synchronous return; schedule closure.
@@ -1276,9 +1221,27 @@ void GrpcLb::NotifyOnStateChangeLocked(grpc_connectivity_state* current,
                                                  notify);
 }
 
+// Returns the backend addresses extracted from the given addresses.
+UniquePtr<ServerAddressList> ExtractBackendAddresses(
+    const ServerAddressList& addresses) {
+  void* lb_token = (void*)GRPC_MDELEM_LB_TOKEN_EMPTY.payload;
+  grpc_arg arg = grpc_channel_arg_pointer_create(
+      const_cast<char*>(GRPC_ARG_GRPCLB_ADDRESS_LB_TOKEN), lb_token,
+      &lb_token_arg_vtable);
+  auto backend_addresses = MakeUnique<ServerAddressList>();
+  for (size_t i = 0; i < addresses.size(); ++i) {
+    if (!addresses[i].IsBalancer()) {
+      backend_addresses->emplace_back(
+          addresses[i].address(),
+          grpc_channel_args_copy_and_add(addresses[i].args(), &arg, 1));
+    }
+  }
+  return backend_addresses;
+}
+
 void GrpcLb::ProcessChannelArgsLocked(const grpc_channel_args& args) {
-  const grpc_arg* arg = grpc_channel_args_find(&args, GRPC_ARG_LB_ADDRESSES);
-  if (GPR_UNLIKELY(arg == nullptr || arg->type != GRPC_ARG_POINTER)) {
+  const ServerAddressList* addresses = FindServerAddressListChannelArg(&args);
+  if (addresses == nullptr) {
     // Ignore this update.
     gpr_log(
         GPR_ERROR,
@@ -1286,13 +1249,8 @@ void GrpcLb::ProcessChannelArgsLocked(const grpc_channel_args& args) {
         this);
     return;
   }
-  const grpc_lb_addresses* addresses =
-      static_cast<const grpc_lb_addresses*>(arg->value.pointer.p);
   // Update fallback address list.
-  if (fallback_backend_addresses_ != nullptr) {
-    grpc_lb_addresses_destroy(fallback_backend_addresses_);
-  }
-  fallback_backend_addresses_ = ExtractBackendAddresses(addresses);
+  fallback_backend_addresses_ = ExtractBackendAddresses(*addresses);
   // Make sure that GRPC_ARG_LB_POLICY_NAME is set in channel args,
   // since we use this to trigger the client_load_reporting filter.
   static const char* args_to_remove[] = {GRPC_ARG_LB_POLICY_NAME};
@@ -1303,7 +1261,7 @@ void GrpcLb::ProcessChannelArgsLocked(const grpc_channel_args& args) {
       &args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), &new_arg, 1);
   // Construct args for balancer channel.
   grpc_channel_args* lb_channel_args =
-      BuildBalancerChannelArgs(addresses, response_generator_.get(), &args);
+      BuildBalancerChannelArgs(*addresses, response_generator_.get(), &args);
   // Create balancer channel if needed.
   if (lb_channel_ == nullptr) {
     char* uri_str;
@@ -1509,12 +1467,17 @@ void DestroyClientStats(void* arg) {
 }
 
 void GrpcLb::PendingPickSetMetadataAndContext(PendingPick* pp) {
-  /* if connected_subchannel is nullptr, no pick has been made by the RR
-   * policy (e.g., all addresses failed to connect). There won't be any
-   * user_data/token available */
+  // If connected_subchannel is nullptr, no pick has been made by the RR
+  // policy (e.g., all addresses failed to connect). There won't be any
+  // LB token available.
   if (pp->pick->connected_subchannel != nullptr) {
-    if (GPR_LIKELY(!GRPC_MDISNULL(pp->lb_token))) {
-      AddLbTokenToInitialMetadata(GRPC_MDELEM_REF(pp->lb_token),
+    const grpc_arg* arg =
+        grpc_channel_args_find(pp->pick->connected_subchannel->args(),
+                               GRPC_ARG_GRPCLB_ADDRESS_LB_TOKEN);
+    if (arg != nullptr) {
+      grpc_mdelem lb_token = {
+          reinterpret_cast<uintptr_t>(arg->value.pointer.p)};
+      AddLbTokenToInitialMetadata(GRPC_MDELEM_REF(lb_token),
                                   &pp->pick->lb_token_mdelem_storage,
                                   pp->pick->initial_metadata);
     } else {
@@ -1598,12 +1561,10 @@ bool GrpcLb::PickFromRoundRobinPolicyLocked(bool force_async, PendingPick* pp,
       return true;
     }
   }
-  // Set client_stats and user_data.
+  // Set client_stats.
   if (lb_calld_ != nullptr && lb_calld_->client_stats() != nullptr) {
     pp->client_stats = lb_calld_->client_stats()->Ref();
   }
-  GPR_ASSERT(pp->pick->user_data == nullptr);
-  pp->pick->user_data = (void**)&pp->lb_token;
   // Pick via the RR policy.
   bool pick_done = rr_policy_->PickLocked(pp->pick, error);
   if (pick_done) {
@@ -1668,10 +1629,11 @@ void GrpcLb::CreateRoundRobinPolicyLocked(const Args& args) {
 }
 
 grpc_channel_args* GrpcLb::CreateRoundRobinPolicyArgsLocked() {
-  grpc_lb_addresses* addresses;
+  ServerAddressList tmp_addresses;
+  ServerAddressList* addresses = &tmp_addresses;
   bool is_backend_from_grpclb_load_balancer = false;
   if (serverlist_ != nullptr) {
-    addresses = ProcessServerlist(serverlist_);
+    tmp_addresses = ProcessServerlist(serverlist_);
     is_backend_from_grpclb_load_balancer = true;
   } else {
     // If CreateOrUpdateRoundRobinPolicyLocked() is invoked when we haven't
@@ -1680,14 +1642,14 @@ grpc_channel_args* GrpcLb::CreateRoundRobinPolicyArgsLocked() {
     // empty, in which case the new round_robin policy will keep the requested
     // picks pending.
     GPR_ASSERT(fallback_backend_addresses_ != nullptr);
-    addresses = grpc_lb_addresses_copy(fallback_backend_addresses_);
+    addresses = fallback_backend_addresses_.get();
   }
   GPR_ASSERT(addresses != nullptr);
-  // Replace the LB addresses in the channel args that we pass down to
+  // Replace the server address list in the channel args that we pass down to
   // the subchannel.
-  static const char* keys_to_remove[] = {GRPC_ARG_LB_ADDRESSES};
+  static const char* keys_to_remove[] = {GRPC_ARG_SERVER_ADDRESS_LIST};
   grpc_arg args_to_add[3] = {
-      grpc_lb_addresses_create_channel_arg(addresses),
+      CreateServerAddressListChannelArg(addresses),
       // A channel arg indicating if the target is a backend inferred from a
       // grpclb load balancer.
       grpc_channel_arg_integer_create(
@@ -1704,7 +1666,6 @@ grpc_channel_args* GrpcLb::CreateRoundRobinPolicyArgsLocked() {
   grpc_channel_args* args = grpc_channel_args_copy_and_add_and_remove(
       args_, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), args_to_add,
       num_args_to_add);
-  grpc_lb_addresses_destroy(addresses);
   return args;
 }
 
@@ -1837,19 +1798,18 @@ class GrpcLbFactory : public LoadBalancingPolicyFactory {
   OrphanablePtr<LoadBalancingPolicy> CreateLoadBalancingPolicy(
       const LoadBalancingPolicy::Args& args) const override {
     /* Count the number of gRPC-LB addresses. There must be at least one. */
-    const grpc_arg* arg =
-        grpc_channel_args_find(args.args, GRPC_ARG_LB_ADDRESSES);
-    if (arg == nullptr || arg->type != GRPC_ARG_POINTER) {
-      return nullptr;
-    }
-    grpc_lb_addresses* addresses =
-        static_cast<grpc_lb_addresses*>(arg->value.pointer.p);
-    size_t num_grpclb_addrs = 0;
-    for (size_t i = 0; i < addresses->num_addresses; ++i) {
-      if (addresses->addresses[i].is_balancer) ++num_grpclb_addrs;
+    const ServerAddressList* addresses =
+        FindServerAddressListChannelArg(args.args);
+    if (addresses == nullptr) return nullptr;
+    bool found_balancer = false;
+    for (size_t i = 0; i < addresses->size(); ++i) {
+      if ((*addresses)[i].IsBalancer()) {
+        found_balancer = true;
+        break;
+      }
     }
-    if (num_grpclb_addrs == 0) return nullptr;
-    return OrphanablePtr<LoadBalancingPolicy>(New<GrpcLb>(addresses, args));
+    if (!found_balancer) return nullptr;
+    return OrphanablePtr<LoadBalancingPolicy>(New<GrpcLb>(args));
   }
 
   const char* name() const override { return "grpclb"; }

src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h

@@ -21,7 +21,7 @@
 
 #include <grpc/support/port_platform.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include <grpc/impl/codegen/grpc_types.h>
 
 /// Makes any necessary modifications to \a args for use in the grpclb
 /// balancer channel.

src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel_secure.cc

@@ -26,6 +26,7 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/filters/client_channel/client_channel.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
@@ -42,22 +43,23 @@ int BalancerNameCmp(const grpc_core::UniquePtr<char>& a,
 }
 
 RefCountedPtr<TargetAuthorityTable> CreateTargetAuthorityTable(
-    grpc_lb_addresses* addresses) {
+    const ServerAddressList& addresses) {
   TargetAuthorityTable::Entry* target_authority_entries =
-      static_cast<TargetAuthorityTable::Entry*>(gpr_zalloc(
-          sizeof(*target_authority_entries) * addresses->num_addresses));
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
+      static_cast<TargetAuthorityTable::Entry*>(
+          gpr_zalloc(sizeof(*target_authority_entries) * addresses.size()));
+  for (size_t i = 0; i < addresses.size(); ++i) {
     char* addr_str;
-    GPR_ASSERT(grpc_sockaddr_to_string(
-                   &addr_str, &addresses->addresses[i].address, true) > 0);
+    GPR_ASSERT(
+        grpc_sockaddr_to_string(&addr_str, &addresses[i].address(), true) > 0);
     target_authority_entries[i].key = grpc_slice_from_copied_string(addr_str);
-    target_authority_entries[i].value.reset(
-        gpr_strdup(addresses->addresses[i].balancer_name));
     gpr_free(addr_str);
+    char* balancer_name = grpc_channel_arg_get_string(grpc_channel_args_find(
+        addresses[i].args(), GRPC_ARG_ADDRESS_BALANCER_NAME));
+    target_authority_entries[i].value.reset(gpr_strdup(balancer_name));
   }
   RefCountedPtr<TargetAuthorityTable> target_authority_table =
-      TargetAuthorityTable::Create(addresses->num_addresses,
-                                   target_authority_entries, BalancerNameCmp);
+      TargetAuthorityTable::Create(addresses.size(), target_authority_entries,
+                                   BalancerNameCmp);
   gpr_free(target_authority_entries);
   return target_authority_table;
 }
@@ -72,13 +74,12 @@ grpc_channel_args* grpc_lb_policy_grpclb_modify_lb_channel_args(
   grpc_arg args_to_add[2];
   size_t num_args_to_add = 0;
   // Add arg for targets info table.
-  const grpc_arg* arg = grpc_channel_args_find(args, GRPC_ARG_LB_ADDRESSES);
-  GPR_ASSERT(arg != nullptr);
-  GPR_ASSERT(arg->type == GRPC_ARG_POINTER);
-  grpc_lb_addresses* addresses =
-      static_cast<grpc_lb_addresses*>(arg->value.pointer.p);
+  grpc_core::ServerAddressList* addresses =
+      grpc_core::FindServerAddressListChannelArg(args);
+  GPR_ASSERT(addresses != nullptr);
   grpc_core::RefCountedPtr<grpc_core::TargetAuthorityTable>
-      target_authority_table = grpc_core::CreateTargetAuthorityTable(addresses);
+      target_authority_table =
+          grpc_core::CreateTargetAuthorityTable(*addresses);
   args_to_add[num_args_to_add++] =
       grpc_core::CreateTargetAuthorityTableChannelArg(
           target_authority_table.get());

src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h

@@ -25,7 +25,7 @@
 
 #include "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h"
 #include "src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h"
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
 
 #define GRPC_GRPCLB_SERVICE_NAME_MAX_LENGTH 128
 

src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc

@@ -24,6 +24,7 @@
 
 #include "src/core/ext/filters/client_channel/lb_policy/subchannel_list.h"
 #include "src/core/ext/filters/client_channel/lb_policy_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/ext/filters/client_channel/subchannel.h"
 #include "src/core/ext/filters/client_channel/subchannel_index.h"
 #include "src/core/lib/channel/channel_args.h"
@@ -75,11 +76,9 @@ class PickFirst : public LoadBalancingPolicy {
     PickFirstSubchannelData(
         SubchannelList<PickFirstSubchannelList, PickFirstSubchannelData>*
             subchannel_list,
-        const grpc_lb_user_data_vtable* user_data_vtable,
-        const grpc_lb_address& address, grpc_subchannel* subchannel,
+        const ServerAddress& address, grpc_subchannel* subchannel,
         grpc_combiner* combiner)
-        : SubchannelData(subchannel_list, user_data_vtable, address, subchannel,
-                         combiner) {}
+        : SubchannelData(subchannel_list, address, subchannel, combiner) {}
 
     void ProcessConnectivityChangeLocked(
         grpc_connectivity_state connectivity_state, grpc_error* error) override;
@@ -95,7 +94,7 @@ class PickFirst : public LoadBalancingPolicy {
                               PickFirstSubchannelData> {
    public:
     PickFirstSubchannelList(PickFirst* policy, TraceFlag* tracer,
-                            const grpc_lb_addresses* addresses,
+                            const ServerAddressList& addresses,
                             grpc_combiner* combiner,
                             grpc_client_channel_factory* client_channel_factory,
                             const grpc_channel_args& args)
@@ -337,8 +336,8 @@ void PickFirst::UpdateChildRefsLocked() {
 void PickFirst::UpdateLocked(const grpc_channel_args& args,
                              grpc_json* lb_config) {
   AutoChildRefsUpdater guard(this);
-  const grpc_arg* arg = grpc_channel_args_find(&args, GRPC_ARG_LB_ADDRESSES);
-  if (arg == nullptr || arg->type != GRPC_ARG_POINTER) {
+  const ServerAddressList* addresses = FindServerAddressListChannelArg(&args);
+  if (addresses == nullptr) {
     if (subchannel_list_ == nullptr) {
       // If we don't have a current subchannel list, go into TRANSIENT FAILURE.
       grpc_connectivity_state_set(
@@ -354,19 +353,17 @@ void PickFirst::UpdateLocked(const grpc_channel_args& args,
     }
     return;
   }
-  const grpc_lb_addresses* addresses =
-      static_cast<const grpc_lb_addresses*>(arg->value.pointer.p);
   if (grpc_lb_pick_first_trace.enabled()) {
     gpr_log(GPR_INFO,
             "Pick First %p received update with %" PRIuPTR " addresses", this,
-            addresses->num_addresses);
+            addresses->size());
   }
   grpc_arg new_arg = grpc_channel_arg_integer_create(
       const_cast<char*>(GRPC_ARG_INHIBIT_HEALTH_CHECKING), 1);
   grpc_channel_args* new_args =
       grpc_channel_args_copy_and_add(&args, &new_arg, 1);
   auto subchannel_list = MakeOrphanable<PickFirstSubchannelList>(
-      this, &grpc_lb_pick_first_trace, addresses, combiner(),
+      this, &grpc_lb_pick_first_trace, *addresses, combiner(),
       client_channel_factory(), *new_args);
   grpc_channel_args_destroy(new_args);
   if (subchannel_list->num_subchannels() == 0) {

src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc

@@ -82,8 +82,6 @@ class RoundRobin : public LoadBalancingPolicy {
 
   // Data for a particular subchannel in a subchannel list.
   // This subclass adds the following functionality:
-  // - Tracks user_data associated with each address, which will be
-  //   returned along with picks that select the subchannel.
   // - Tracks the previous connectivity state of the subchannel, so that
   //   we know how many subchannels are in each state.
   class RoundRobinSubchannelData
@@ -93,26 +91,9 @@ class RoundRobin : public LoadBalancingPolicy {
     RoundRobinSubchannelData(
         SubchannelList<RoundRobinSubchannelList, RoundRobinSubchannelData>*
             subchannel_list,
-        const grpc_lb_user_data_vtable* user_data_vtable,
-        const grpc_lb_address& address, grpc_subchannel* subchannel,
+        const ServerAddress& address, grpc_subchannel* subchannel,
         grpc_combiner* combiner)
-        : SubchannelData(subchannel_list, user_data_vtable, address, subchannel,
-                         combiner),
-          user_data_vtable_(user_data_vtable),
-          user_data_(user_data_vtable_ != nullptr
-                         ? user_data_vtable_->copy(address.user_data)
-                         : nullptr) {}
-
-    void UnrefSubchannelLocked(const char* reason) override {
-      SubchannelData::UnrefSubchannelLocked(reason);
-      if (user_data_ != nullptr) {
-        GPR_ASSERT(user_data_vtable_ != nullptr);
-        user_data_vtable_->destroy(user_data_);
-        user_data_ = nullptr;
-      }
-    }
-
-    void* user_data() const { return user_data_; }
+        : SubchannelData(subchannel_list, address, subchannel, combiner) {}
 
     grpc_connectivity_state connectivity_state() const {
       return last_connectivity_state_;
@@ -125,8 +106,6 @@ class RoundRobin : public LoadBalancingPolicy {
     void ProcessConnectivityChangeLocked(
         grpc_connectivity_state connectivity_state, grpc_error* error) override;
 
-    const grpc_lb_user_data_vtable* user_data_vtable_;
-    void* user_data_ = nullptr;
     grpc_connectivity_state last_connectivity_state_ = GRPC_CHANNEL_IDLE;
   };
 
@@ -137,7 +116,7 @@ class RoundRobin : public LoadBalancingPolicy {
    public:
     RoundRobinSubchannelList(
         RoundRobin* policy, TraceFlag* tracer,
-        const grpc_lb_addresses* addresses, grpc_combiner* combiner,
+        const ServerAddressList& addresses, grpc_combiner* combiner,
         grpc_client_channel_factory* client_channel_factory,
         const grpc_channel_args& args)
         : SubchannelList(policy, tracer, addresses, combiner,
@@ -354,9 +333,6 @@ bool RoundRobin::DoPickLocked(PickState* pick) {
         subchannel_list_->subchannel(next_ready_index);
     GPR_ASSERT(sd->connected_subchannel() != nullptr);
     pick->connected_subchannel = sd->connected_subchannel()->Ref();
-    if (pick->user_data != nullptr) {
-      *pick->user_data = sd->user_data();
-    }
     if (grpc_lb_round_robin_trace.enabled()) {
       gpr_log(GPR_INFO,
               "[RR %p] Picked target <-- Subchannel %p (connected %p) (sl %p, "
@@ -667,9 +643,9 @@ void RoundRobin::NotifyOnStateChangeLocked(grpc_connectivity_state* current,
 
 void RoundRobin::UpdateLocked(const grpc_channel_args& args,
                               grpc_json* lb_config) {
-  const grpc_arg* arg = grpc_channel_args_find(&args, GRPC_ARG_LB_ADDRESSES);
   AutoChildRefsUpdater guard(this);
-  if (GPR_UNLIKELY(arg == nullptr || arg->type != GRPC_ARG_POINTER)) {
+  const ServerAddressList* addresses = FindServerAddressListChannelArg(&args);
+  if (addresses == nullptr) {
     gpr_log(GPR_ERROR, "[RR %p] update provided no addresses; ignoring", this);
     // If we don't have a current subchannel list, go into TRANSIENT_FAILURE.
     // Otherwise, keep using the current subchannel list (ignore this update).
@@ -681,11 +657,9 @@ void RoundRobin::UpdateLocked(const grpc_channel_args& args,
     }
     return;
   }
-  grpc_lb_addresses* addresses =
-      static_cast<grpc_lb_addresses*>(arg->value.pointer.p);
   if (grpc_lb_round_robin_trace.enabled()) {
     gpr_log(GPR_INFO, "[RR %p] received update with %" PRIuPTR " addresses",
-            this, addresses->num_addresses);
+            this, addresses->size());
   }
   // Replace latest_pending_subchannel_list_.
   if (latest_pending_subchannel_list_ != nullptr) {
@@ -696,7 +670,7 @@ void RoundRobin::UpdateLocked(const grpc_channel_args& args,
     }
   }
   latest_pending_subchannel_list_ = MakeOrphanable<RoundRobinSubchannelList>(
-      this, &grpc_lb_round_robin_trace, addresses, combiner(),
+      this, &grpc_lb_round_robin_trace, *addresses, combiner(),
       client_channel_factory(), args);
   // If we haven't started picking yet or the new list is empty,
   // immediately promote the new list to the current list.

src/core/ext/filters/client_channel/lb_policy/subchannel_list.h

@@ -26,6 +26,7 @@
 #include <grpc/support/alloc.h>
 
 #include "src/core/ext/filters/client_channel/lb_policy_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/ext/filters/client_channel/subchannel.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/debug/trace.h"
@@ -141,8 +142,7 @@ class SubchannelData {
  protected:
   SubchannelData(
       SubchannelList<SubchannelListType, SubchannelDataType>* subchannel_list,
-      const grpc_lb_user_data_vtable* user_data_vtable,
-      const grpc_lb_address& address, grpc_subchannel* subchannel,
+      const ServerAddress& address, grpc_subchannel* subchannel,
       grpc_combiner* combiner);
 
   virtual ~SubchannelData();
@@ -156,9 +156,8 @@ class SubchannelData {
       grpc_connectivity_state connectivity_state,
       grpc_error* error) GRPC_ABSTRACT;
 
-  // Unrefs the subchannel.  May be overridden by subclasses that need
-  // to perform extra cleanup when unreffing the subchannel.
-  virtual void UnrefSubchannelLocked(const char* reason);
+  // Unrefs the subchannel.
+  void UnrefSubchannelLocked(const char* reason);
 
  private:
   // Updates connected_subchannel_ based on pending_connectivity_state_unsafe_.
@@ -232,7 +231,7 @@ class SubchannelList : public InternallyRefCounted<SubchannelListType> {
 
  protected:
   SubchannelList(LoadBalancingPolicy* policy, TraceFlag* tracer,
-                 const grpc_lb_addresses* addresses, grpc_combiner* combiner,
+                 const ServerAddressList& addresses, grpc_combiner* combiner,
                  grpc_client_channel_factory* client_channel_factory,
                  const grpc_channel_args& args);
 
@@ -277,8 +276,7 @@ class SubchannelList : public InternallyRefCounted<SubchannelListType> {
 template <typename SubchannelListType, typename SubchannelDataType>
 SubchannelData<SubchannelListType, SubchannelDataType>::SubchannelData(
     SubchannelList<SubchannelListType, SubchannelDataType>* subchannel_list,
-    const grpc_lb_user_data_vtable* user_data_vtable,
-    const grpc_lb_address& address, grpc_subchannel* subchannel,
+    const ServerAddress& address, grpc_subchannel* subchannel,
     grpc_combiner* combiner)
     : subchannel_list_(subchannel_list),
       subchannel_(subchannel),
@@ -488,7 +486,7 @@ void SubchannelData<SubchannelListType, SubchannelDataType>::ShutdownLocked() {
 template <typename SubchannelListType, typename SubchannelDataType>
 SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
     LoadBalancingPolicy* policy, TraceFlag* tracer,
-    const grpc_lb_addresses* addresses, grpc_combiner* combiner,
+    const ServerAddressList& addresses, grpc_combiner* combiner,
     grpc_client_channel_factory* client_channel_factory,
     const grpc_channel_args& args)
     : InternallyRefCounted<SubchannelListType>(tracer),
@@ -498,9 +496,9 @@ SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
   if (tracer_->enabled()) {
     gpr_log(GPR_INFO,
             "[%s %p] Creating subchannel list %p for %" PRIuPTR " subchannels",
-            tracer_->name(), policy, this, addresses->num_addresses);
+            tracer_->name(), policy, this, addresses.size());
   }
-  subchannels_.reserve(addresses->num_addresses);
+  subchannels_.reserve(addresses.size());
   // We need to remove the LB addresses in order to be able to compare the
   // subchannel keys of subchannels from a different batch of addresses.
   // We also remove the inhibit-health-checking arg, since we are
@@ -508,19 +506,27 @@ SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
   inhibit_health_checking_ = grpc_channel_arg_get_bool(
       grpc_channel_args_find(&args, GRPC_ARG_INHIBIT_HEALTH_CHECKING), false);
   static const char* keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS,
-                                         GRPC_ARG_LB_ADDRESSES,
+                                         GRPC_ARG_SERVER_ADDRESS_LIST,
                                          GRPC_ARG_INHIBIT_HEALTH_CHECKING};
   // Create a subchannel for each address.
   grpc_subchannel_args sc_args;
-  for (size_t i = 0; i < addresses->num_addresses; i++) {
-    // If there were any balancer, we would have chosen grpclb policy instead.
-    GPR_ASSERT(!addresses->addresses[i].is_balancer);
+  for (size_t i = 0; i < addresses.size(); i++) {
+    // If there were any balancer addresses, we would have chosen grpclb
+    // policy, which does not use a SubchannelList.
+    GPR_ASSERT(!addresses[i].IsBalancer());
     memset(&sc_args, 0, sizeof(grpc_subchannel_args));
-    grpc_arg addr_arg =
-        grpc_create_subchannel_address_arg(&addresses->addresses[i].address);
+    InlinedVector<grpc_arg, 4> args_to_add;
+    args_to_add.emplace_back(
+        grpc_create_subchannel_address_arg(&addresses[i].address()));
+    if (addresses[i].args() != nullptr) {
+      for (size_t j = 0; j < addresses[i].args()->num_args; ++j) {
+        args_to_add.emplace_back(addresses[i].args()->args[j]);
+      }
+    }
     grpc_channel_args* new_args = grpc_channel_args_copy_and_add_and_remove(
-        &args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &addr_arg, 1);
-    gpr_free(addr_arg.value.string);
+        &args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove),
+        args_to_add.data(), args_to_add.size());
+    gpr_free(args_to_add[0].value.string);
     sc_args.args = new_args;
     grpc_subchannel* subchannel = grpc_client_channel_factory_create_subchannel(
         client_channel_factory, &sc_args);
@@ -528,8 +534,7 @@ SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
     if (subchannel == nullptr) {
       // Subchannel could not be created.
       if (tracer_->enabled()) {
-        char* address_uri =
-            grpc_sockaddr_to_uri(&addresses->addresses[i].address);
+        char* address_uri = grpc_sockaddr_to_uri(&addresses[i].address());
         gpr_log(GPR_INFO,
                 "[%s %p] could not create subchannel for address uri %s, "
                 "ignoring",
@@ -539,8 +544,7 @@ SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
       continue;
     }
     if (tracer_->enabled()) {
-      char* address_uri =
-          grpc_sockaddr_to_uri(&addresses->addresses[i].address);
+      char* address_uri = grpc_sockaddr_to_uri(&addresses[i].address());
       gpr_log(GPR_INFO,
               "[%s %p] subchannel list %p index %" PRIuPTR
               ": Created subchannel %p for address uri %s",
@@ -548,8 +552,7 @@ SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
               address_uri);
       gpr_free(address_uri);
     }
-    subchannels_.emplace_back(this, addresses->user_data_vtable,
-                              addresses->addresses[i], subchannel, combiner);
+    subchannels_.emplace_back(this, addresses[i], subchannel, combiner);
   }
 }
 

src/core/ext/filters/client_channel/lb_policy/xds/xds.cc

@@ -79,6 +79,7 @@
 #include "src/core/ext/filters/client_channel/lb_policy_registry.h"
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/ext/filters/client_channel/subchannel_index.h"
 #include "src/core/lib/backoff/backoff.h"
 #include "src/core/lib/channel/channel_args.h"
@@ -116,7 +117,7 @@ namespace {
 
 class XdsLb : public LoadBalancingPolicy {
  public:
-  XdsLb(const grpc_lb_addresses* addresses, const Args& args);
+  explicit XdsLb(const Args& args);
 
   void UpdateLocked(const grpc_channel_args& args,
                     grpc_json* lb_config) override;
@@ -156,9 +157,6 @@ class XdsLb : public LoadBalancingPolicy {
     // Our on_complete closure and the original one.
     grpc_closure on_complete;
     grpc_closure* original_on_complete;
-    // The LB token associated with the pick.  This is set via user_data in
-    // the pick.
-    grpc_mdelem lb_token;
     // Stats for client-side load reporting.
     RefCountedPtr<XdsLbClientStats> client_stats;
     // Next pending pick.
@@ -256,7 +254,7 @@ class XdsLb : public LoadBalancingPolicy {
                                                          grpc_error* error);
 
   // Pending pick methods.
-  static void PendingPickSetMetadataAndContext(PendingPick* pp);
+  static void PendingPickCleanup(PendingPick* pp);
   PendingPick* PendingPickCreate(PickState* pick);
   void AddPendingPick(PendingPick* pp);
   static void OnPendingPickComplete(void* arg, grpc_error* error);
@@ -319,7 +317,7 @@ class XdsLb : public LoadBalancingPolicy {
   // 0 means not using fallback.
   int lb_fallback_timeout_ms_ = 0;
   // The backend addresses from the resolver.
-  grpc_lb_addresses* fallback_backend_addresses_ = nullptr;
+  UniquePtr<ServerAddressList> fallback_backend_addresses_;
   // Fallback timer.
   bool fallback_timer_callback_pending_ = false;
   grpc_timer lb_fallback_timer_;
@@ -339,47 +337,15 @@ class XdsLb : public LoadBalancingPolicy {
 // serverlist parsing code
 //
 
-// vtable for LB tokens in grpc_lb_addresses
-void* lb_token_copy(void* token) {
-  return token == nullptr
-             ? nullptr
-             : (void*)GRPC_MDELEM_REF(grpc_mdelem{(uintptr_t)token}).payload;
-}
-void lb_token_destroy(void* token) {
-  if (token != nullptr) {
-    GRPC_MDELEM_UNREF(grpc_mdelem{(uintptr_t)token});
-  }
-}
-int lb_token_cmp(void* token1, void* token2) {
-  if (token1 > token2) return 1;
-  if (token1 < token2) return -1;
-  return 0;
-}
-const grpc_lb_user_data_vtable lb_token_vtable = {
-    lb_token_copy, lb_token_destroy, lb_token_cmp};
-
 // Returns the backend addresses extracted from the given addresses.
-grpc_lb_addresses* ExtractBackendAddresses(const grpc_lb_addresses* addresses) {
-  // First pass: count the number of backend addresses.
-  size_t num_backends = 0;
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    if (!addresses->addresses[i].is_balancer) {
-      ++num_backends;
+UniquePtr<ServerAddressList> ExtractBackendAddresses(
+    const ServerAddressList& addresses) {
+  auto backend_addresses = MakeUnique<ServerAddressList>();
+  for (size_t i = 0; i < addresses.size(); ++i) {
+    if (!addresses[i].IsBalancer()) {
+      backend_addresses->emplace_back(addresses[i]);
     }
   }
-  // Second pass: actually populate the addresses and (empty) LB tokens.
-  grpc_lb_addresses* backend_addresses =
-      grpc_lb_addresses_create(num_backends, &lb_token_vtable);
-  size_t num_copied = 0;
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    if (addresses->addresses[i].is_balancer) continue;
-    const grpc_resolved_address* addr = &addresses->addresses[i].address;
-    grpc_lb_addresses_set_address(backend_addresses, num_copied, &addr->addr,
-                                  addr->len, false /* is_balancer */,
-                                  nullptr /* balancer_name */,
-                                  (void*)GRPC_MDELEM_LB_TOKEN_EMPTY.payload);
-    ++num_copied;
-  }
   return backend_addresses;
 }
 
@@ -429,56 +395,17 @@ void ParseServer(const xds_grpclb_server* server, grpc_resolved_address* addr) {
 }
 
 // Returns addresses extracted from \a serverlist.
-grpc_lb_addresses* ProcessServerlist(const xds_grpclb_serverlist* serverlist) {
-  size_t num_valid = 0;
-  /* first pass: count how many are valid in order to allocate the necessary
-   * memory in a single block */
+UniquePtr<ServerAddressList> ProcessServerlist(
+    const xds_grpclb_serverlist* serverlist) {
+  auto addresses = MakeUnique<ServerAddressList>();
   for (size_t i = 0; i < serverlist->num_servers; ++i) {
-    if (IsServerValid(serverlist->servers[i], i, true)) ++num_valid;
-  }
-  grpc_lb_addresses* lb_addresses =
-      grpc_lb_addresses_create(num_valid, &lb_token_vtable);
-  /* second pass: actually populate the addresses and LB tokens (aka user data
-   * to the outside world) to be read by the child policy during its creation.
-   * Given that the validity tests are very cheap, they are performed again
-   * instead of marking the valid ones during the first pass, as this would
-   * incurr in an allocation due to the arbitrary number of server */
-  size_t addr_idx = 0;
-  for (size_t sl_idx = 0; sl_idx < serverlist->num_servers; ++sl_idx) {
-    const xds_grpclb_server* server = serverlist->servers[sl_idx];
-    if (!IsServerValid(serverlist->servers[sl_idx], sl_idx, false)) continue;
-    GPR_ASSERT(addr_idx < num_valid);
-    /* address processing */
+    const xds_grpclb_server* server = serverlist->servers[i];
+    if (!IsServerValid(serverlist->servers[i], i, false)) continue;
     grpc_resolved_address addr;
     ParseServer(server, &addr);
-    /* lb token processing */
-    void* user_data;
-    if (server->has_load_balance_token) {
-      const size_t lb_token_max_length =
-          GPR_ARRAY_SIZE(server->load_balance_token);
-      const size_t lb_token_length =
-          strnlen(server->load_balance_token, lb_token_max_length);
-      grpc_slice lb_token_mdstr = grpc_slice_from_copied_buffer(
-          server->load_balance_token, lb_token_length);
-      user_data =
-          (void*)grpc_mdelem_from_slices(GRPC_MDSTR_LB_TOKEN, lb_token_mdstr)
-              .payload;
-    } else {
-      char* uri = grpc_sockaddr_to_uri(&addr);
-      gpr_log(GPR_INFO,
-              "Missing LB token for backend address '%s'. The empty token will "
-              "be used instead",
-              uri);
-      gpr_free(uri);
-      user_data = (void*)GRPC_MDELEM_LB_TOKEN_EMPTY.payload;
-    }
-    grpc_lb_addresses_set_address(lb_addresses, addr_idx, &addr.addr, addr.len,
-                                  false /* is_balancer */,
-                                  nullptr /* balancer_name */, user_data);
-    ++addr_idx;
+    addresses->emplace_back(addr, nullptr);
   }
-  GPR_ASSERT(addr_idx == num_valid);
-  return lb_addresses;
+  return addresses;
 }
 
 //
@@ -789,8 +716,7 @@ void XdsLb::BalancerCallState::OnBalancerMessageReceivedLocked(
           xds_grpclb_destroy_serverlist(xdslb_policy->serverlist_);
         } else {
           /* or dispose of the fallback */
-          grpc_lb_addresses_destroy(xdslb_policy->fallback_backend_addresses_);
-          xdslb_policy->fallback_backend_addresses_ = nullptr;
+          xdslb_policy->fallback_backend_addresses_.reset();
           if (xdslb_policy->fallback_timer_callback_pending_) {
             grpc_timer_cancel(&xdslb_policy->lb_fallback_timer_);
           }
@@ -876,31 +802,15 @@ void XdsLb::BalancerCallState::OnBalancerStatusReceivedLocked(
 // helper code for creating balancer channel
 //
 
-grpc_lb_addresses* ExtractBalancerAddresses(
-    const grpc_lb_addresses* addresses) {
-  size_t num_grpclb_addrs = 0;
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    if (addresses->addresses[i].is_balancer) ++num_grpclb_addrs;
-  }
-  // There must be at least one balancer address, or else the
-  // client_channel would not have chosen this LB policy.
-  GPR_ASSERT(num_grpclb_addrs > 0);
-  grpc_lb_addresses* lb_addresses =
-      grpc_lb_addresses_create(num_grpclb_addrs, nullptr);
-  size_t lb_addresses_idx = 0;
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    if (!addresses->addresses[i].is_balancer) continue;
-    if (GPR_UNLIKELY(addresses->addresses[i].user_data != nullptr)) {
-      gpr_log(GPR_ERROR,
-              "This LB policy doesn't support user data. It will be ignored");
+UniquePtr<ServerAddressList> ExtractBalancerAddresses(
+    const ServerAddressList& addresses) {
+  auto balancer_addresses = MakeUnique<ServerAddressList>();
+  for (size_t i = 0; i < addresses.size(); ++i) {
+    if (addresses[i].IsBalancer()) {
+      balancer_addresses->emplace_back(addresses[i]);
     }
-    grpc_lb_addresses_set_address(
-        lb_addresses, lb_addresses_idx++, addresses->addresses[i].address.addr,
-        addresses->addresses[i].address.len, false /* is balancer */,
-        addresses->addresses[i].balancer_name, nullptr /* user data */);
   }
-  GPR_ASSERT(num_grpclb_addrs == lb_addresses_idx);
-  return lb_addresses;
+  return balancer_addresses;
 }
 
 /* Returns the channel args for the LB channel, used to create a bidirectional
@@ -912,10 +822,11 @@ grpc_lb_addresses* ExtractBalancerAddresses(
  *   above the grpclb policy.
  *   - \a args: other args inherited from the xds policy. */
 grpc_channel_args* BuildBalancerChannelArgs(
-    const grpc_lb_addresses* addresses,
+    const ServerAddressList& addresses,
     FakeResolverResponseGenerator* response_generator,
     const grpc_channel_args* args) {
-  grpc_lb_addresses* lb_addresses = ExtractBalancerAddresses(addresses);
+  UniquePtr<ServerAddressList> balancer_addresses =
+      ExtractBalancerAddresses(addresses);
   // Channel args to remove.
   static const char* args_to_remove[] = {
       // LB policy name, since we want to use the default (pick_first) in
@@ -933,7 +844,7 @@ grpc_channel_args* BuildBalancerChannelArgs(
       // is_balancer=true.  We need the LB channel to return addresses with
       // is_balancer=false so that it does not wind up recursively using the
       // xds LB policy, as per the special case logic in client_channel.c.
-      GRPC_ARG_LB_ADDRESSES,
+      GRPC_ARG_SERVER_ADDRESS_LIST,
       // The fake resolver response generator, because we are replacing it
       // with the one from the xds policy, used to propagate updates to
       // the LB channel.
@@ -949,10 +860,10 @@ grpc_channel_args* BuildBalancerChannelArgs(
   };
   // Channel args to add.
   const grpc_arg args_to_add[] = {
-      // New LB addresses.
+      // New server address list.
       // Note that we pass these in both when creating the LB channel
       // and via the fake resolver.  The latter is what actually gets used.
-      grpc_lb_addresses_create_channel_arg(lb_addresses),
+      CreateServerAddressListChannelArg(balancer_addresses.get()),
       // The fake resolver response generator, which we use to inject
       // address updates into the LB channel.
       grpc_core::FakeResolverResponseGenerator::MakeChannelArg(
@@ -970,10 +881,7 @@ grpc_channel_args* BuildBalancerChannelArgs(
       args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), args_to_add,
       GPR_ARRAY_SIZE(args_to_add));
   // Make any necessary modifications for security.
-  new_args = grpc_lb_policy_xds_modify_lb_channel_args(new_args);
-  // Clean up.
-  grpc_lb_addresses_destroy(lb_addresses);
-  return new_args;
+  return grpc_lb_policy_xds_modify_lb_channel_args(new_args);
 }
 
 //
@@ -981,8 +889,7 @@ grpc_channel_args* BuildBalancerChannelArgs(
 //
 
 // TODO(vishalpowar): Use lb_config in args to configure LB policy.
-XdsLb::XdsLb(const grpc_lb_addresses* addresses,
-             const LoadBalancingPolicy::Args& args)
+XdsLb::XdsLb(const LoadBalancingPolicy::Args& args)
     : LoadBalancingPolicy(args),
       response_generator_(MakeRefCounted<FakeResolverResponseGenerator>()),
       lb_call_backoff_(
@@ -1038,9 +945,6 @@ XdsLb::~XdsLb() {
   if (serverlist_ != nullptr) {
     xds_grpclb_destroy_serverlist(serverlist_);
   }
-  if (fallback_backend_addresses_ != nullptr) {
-    grpc_lb_addresses_destroy(fallback_backend_addresses_);
-  }
   grpc_subchannel_index_unref();
 }
 
@@ -1088,7 +992,6 @@ void XdsLb::HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) {
   while ((pp = pending_picks_) != nullptr) {
     pending_picks_ = pp->next;
     pp->pick->on_complete = pp->original_on_complete;
-    pp->pick->user_data = nullptr;
     grpc_error* error = GRPC_ERROR_NONE;
     if (new_policy->PickLocked(pp->pick, &error)) {
       // Synchronous return; schedule closure.
@@ -1241,21 +1144,16 @@ void XdsLb::NotifyOnStateChangeLocked(grpc_connectivity_state* current,
 }
 
 void XdsLb::ProcessChannelArgsLocked(const grpc_channel_args& args) {
-  const grpc_arg* arg = grpc_channel_args_find(&args, GRPC_ARG_LB_ADDRESSES);
-  if (GPR_UNLIKELY(arg == nullptr || arg->type != GRPC_ARG_POINTER)) {
+  const ServerAddressList* addresses = FindServerAddressListChannelArg(&args);
+  if (addresses == nullptr) {
     // Ignore this update.
     gpr_log(GPR_ERROR,
             "[xdslb %p] No valid LB addresses channel arg in update, ignoring.",
             this);
     return;
   }
-  const grpc_lb_addresses* addresses =
-      static_cast<const grpc_lb_addresses*>(arg->value.pointer.p);
   // Update fallback address list.
-  if (fallback_backend_addresses_ != nullptr) {
-    grpc_lb_addresses_destroy(fallback_backend_addresses_);
-  }
-  fallback_backend_addresses_ = ExtractBackendAddresses(addresses);
+  fallback_backend_addresses_ = ExtractBackendAddresses(*addresses);
   // Make sure that GRPC_ARG_LB_POLICY_NAME is set in channel args,
   // since we use this to trigger the client_load_reporting filter.
   static const char* args_to_remove[] = {GRPC_ARG_LB_POLICY_NAME};
@@ -1266,7 +1164,7 @@ void XdsLb::ProcessChannelArgsLocked(const grpc_channel_args& args) {
       &args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), &new_arg, 1);
   // Construct args for balancer channel.
   grpc_channel_args* lb_channel_args =
-      BuildBalancerChannelArgs(addresses, response_generator_.get(), &args);
+      BuildBalancerChannelArgs(*addresses, response_generator_.get(), &args);
   // Create balancer channel if needed.
   if (lb_channel_ == nullptr) {
     char* uri_str;
@@ -1457,37 +1355,15 @@ void XdsLb::OnBalancerChannelConnectivityChangedLocked(void* arg,
 // PendingPick
 //
 
-// Adds lb_token of selected subchannel (address) to the call's initial
-// metadata.
-grpc_error* AddLbTokenToInitialMetadata(
-    grpc_mdelem lb_token, grpc_linked_mdelem* lb_token_mdelem_storage,
-    grpc_metadata_batch* initial_metadata) {
-  GPR_ASSERT(lb_token_mdelem_storage != nullptr);
-  GPR_ASSERT(!GRPC_MDISNULL(lb_token));
-  return grpc_metadata_batch_add_tail(initial_metadata, lb_token_mdelem_storage,
-                                      lb_token);
-}
-
 // Destroy function used when embedding client stats in call context.
 void DestroyClientStats(void* arg) {
   static_cast<XdsLbClientStats*>(arg)->Unref();
 }
 
-void XdsLb::PendingPickSetMetadataAndContext(PendingPick* pp) {
-  /* if connected_subchannel is nullptr, no pick has been made by the
-   * child policy (e.g., all addresses failed to connect). There won't be any
-   * user_data/token available */
+void XdsLb::PendingPickCleanup(PendingPick* pp) {
+  // If connected_subchannel is nullptr, no pick has been made by the
+  // child policy (e.g., all addresses failed to connect).
   if (pp->pick->connected_subchannel != nullptr) {
-    if (GPR_LIKELY(!GRPC_MDISNULL(pp->lb_token))) {
-      AddLbTokenToInitialMetadata(GRPC_MDELEM_REF(pp->lb_token),
-                                  &pp->pick->lb_token_mdelem_storage,
-                                  pp->pick->initial_metadata);
-    } else {
-      gpr_log(GPR_ERROR,
-              "[xdslb %p] No LB token for connected subchannel pick %p",
-              pp->xdslb_policy, pp->pick);
-      abort();
-    }
     // Pass on client stats via context. Passes ownership of the reference.
     if (pp->client_stats != nullptr) {
       pp->pick->subchannel_call_context[GRPC_GRPCLB_CLIENT_STATS].value =
@@ -1505,7 +1381,7 @@ void XdsLb::PendingPickSetMetadataAndContext(PendingPick* pp) {
  * order to unref the child policy instance upon its invocation */
 void XdsLb::OnPendingPickComplete(void* arg, grpc_error* error) {
   PendingPick* pp = static_cast<PendingPick*>(arg);
-  PendingPickSetMetadataAndContext(pp);
+  PendingPickCleanup(pp);
   GRPC_CLOSURE_SCHED(pp->original_on_complete, GRPC_ERROR_REF(error));
   Delete(pp);
 }
@@ -1537,16 +1413,14 @@ void XdsLb::AddPendingPick(PendingPick* pp) {
 // completion callback even if the pick is available immediately.
 bool XdsLb::PickFromChildPolicyLocked(bool force_async, PendingPick* pp,
                                       grpc_error** error) {
-  // Set client_stats and user_data.
+  // Set client_stats.
   if (lb_calld_ != nullptr && lb_calld_->client_stats() != nullptr) {
     pp->client_stats = lb_calld_->client_stats()->Ref();
   }
-  GPR_ASSERT(pp->pick->user_data == nullptr);
-  pp->pick->user_data = (void**)&pp->lb_token;
   // Pick via the child policy.
   bool pick_done = child_policy_->PickLocked(pp->pick, error);
   if (pick_done) {
-    PendingPickSetMetadataAndContext(pp);
+    PendingPickCleanup(pp);
     if (force_async) {
       GRPC_CLOSURE_SCHED(pp->original_on_complete, *error);
       *error = GRPC_ERROR_NONE;
@@ -1608,20 +1482,19 @@ void XdsLb::CreateChildPolicyLocked(const Args& args) {
 }
 
 grpc_channel_args* XdsLb::CreateChildPolicyArgsLocked() {
-  grpc_lb_addresses* addresses;
   bool is_backend_from_grpclb_load_balancer = false;
   // This should never be invoked if we do not have serverlist_, as fallback
   // mode is disabled for xDS plugin.
   GPR_ASSERT(serverlist_ != nullptr);
   GPR_ASSERT(serverlist_->num_servers > 0);
-  addresses = ProcessServerlist(serverlist_);
-  is_backend_from_grpclb_load_balancer = true;
+  UniquePtr<ServerAddressList> addresses = ProcessServerlist(serverlist_);
   GPR_ASSERT(addresses != nullptr);
-  // Replace the LB addresses in the channel args that we pass down to
+  is_backend_from_grpclb_load_balancer = true;
+  // Replace the server address list in the channel args that we pass down to
   // the subchannel.
-  static const char* keys_to_remove[] = {GRPC_ARG_LB_ADDRESSES};
+  static const char* keys_to_remove[] = {GRPC_ARG_SERVER_ADDRESS_LIST};
   const grpc_arg args_to_add[] = {
-      grpc_lb_addresses_create_channel_arg(addresses),
+      CreateServerAddressListChannelArg(addresses.get()),
       // A channel arg indicating if the target is a backend inferred from a
       // grpclb load balancer.
       grpc_channel_arg_integer_create(
@@ -1631,7 +1504,6 @@ grpc_channel_args* XdsLb::CreateChildPolicyArgsLocked() {
   grpc_channel_args* args = grpc_channel_args_copy_and_add_and_remove(
       args_, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), args_to_add,
       GPR_ARRAY_SIZE(args_to_add));
-  grpc_lb_addresses_destroy(addresses);
   return args;
 }
 
@@ -1765,19 +1637,18 @@ class XdsFactory : public LoadBalancingPolicyFactory {
   OrphanablePtr<LoadBalancingPolicy> CreateLoadBalancingPolicy(
       const LoadBalancingPolicy::Args& args) const override {
     /* Count the number of gRPC-LB addresses. There must be at least one. */
-    const grpc_arg* arg =
-        grpc_channel_args_find(args.args, GRPC_ARG_LB_ADDRESSES);
-    if (arg == nullptr || arg->type != GRPC_ARG_POINTER) {
-      return nullptr;
-    }
-    grpc_lb_addresses* addresses =
-        static_cast<grpc_lb_addresses*>(arg->value.pointer.p);
-    size_t num_grpclb_addrs = 0;
-    for (size_t i = 0; i < addresses->num_addresses; ++i) {
-      if (addresses->addresses[i].is_balancer) ++num_grpclb_addrs;
+    const ServerAddressList* addresses =
+        FindServerAddressListChannelArg(args.args);
+    if (addresses == nullptr) return nullptr;
+    bool found_balancer_address = false;
+    for (size_t i = 0; i < addresses->size(); ++i) {
+      if ((*addresses)[i].IsBalancer()) {
+        found_balancer_address = true;
+        break;
+      }
     }
-    if (num_grpclb_addrs == 0) return nullptr;
-    return OrphanablePtr<LoadBalancingPolicy>(New<XdsLb>(addresses, args));
+    if (!found_balancer_address) return nullptr;
+    return OrphanablePtr<LoadBalancingPolicy>(New<XdsLb>(args));
   }
 
   const char* name() const override { return "xds_experimental"; }

src/core/ext/filters/client_channel/lb_policy/xds/xds_channel.h

@@ -21,7 +21,7 @@
 
 #include <grpc/support/port_platform.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include <grpc/impl/codegen/grpc_types.h>
 
 /// Makes any necessary modifications to \a args for use in the xds
 /// balancer channel.

src/core/ext/filters/client_channel/lb_policy/xds/xds_channel_secure.cc

@@ -25,6 +25,7 @@
 #include <string.h>
 
 #include "src/core/ext/filters/client_channel/client_channel.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
@@ -41,22 +42,23 @@ int BalancerNameCmp(const grpc_core::UniquePtr<char>& a,
 }
 
 RefCountedPtr<TargetAuthorityTable> CreateTargetAuthorityTable(
-    grpc_lb_addresses* addresses) {
+    const ServerAddressList& addresses) {
   TargetAuthorityTable::Entry* target_authority_entries =
-      static_cast<TargetAuthorityTable::Entry*>(gpr_zalloc(
-          sizeof(*target_authority_entries) * addresses->num_addresses));
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
+      static_cast<TargetAuthorityTable::Entry*>(
+          gpr_zalloc(sizeof(*target_authority_entries) * addresses.size()));
+  for (size_t i = 0; i < addresses.size(); ++i) {
     char* addr_str;
-    GPR_ASSERT(grpc_sockaddr_to_string(
-                   &addr_str, &addresses->addresses[i].address, true) > 0);
+    GPR_ASSERT(
+        grpc_sockaddr_to_string(&addr_str, &addresses[i].address(), true) > 0);
     target_authority_entries[i].key = grpc_slice_from_copied_string(addr_str);
-    target_authority_entries[i].value.reset(
-        gpr_strdup(addresses->addresses[i].balancer_name));
     gpr_free(addr_str);
+    char* balancer_name = grpc_channel_arg_get_string(grpc_channel_args_find(
+        addresses[i].args(), GRPC_ARG_ADDRESS_BALANCER_NAME));
+    target_authority_entries[i].value.reset(gpr_strdup(balancer_name));
   }
   RefCountedPtr<TargetAuthorityTable> target_authority_table =
-      TargetAuthorityTable::Create(addresses->num_addresses,
-                                   target_authority_entries, BalancerNameCmp);
+      TargetAuthorityTable::Create(addresses.size(), target_authority_entries,
+                                   BalancerNameCmp);
   gpr_free(target_authority_entries);
   return target_authority_table;
 }
@@ -71,13 +73,12 @@ grpc_channel_args* grpc_lb_policy_xds_modify_lb_channel_args(
   grpc_arg args_to_add[2];
   size_t num_args_to_add = 0;
   // Add arg for targets info table.
-  const grpc_arg* arg = grpc_channel_args_find(args, GRPC_ARG_LB_ADDRESSES);
-  GPR_ASSERT(arg != nullptr);
-  GPR_ASSERT(arg->type == GRPC_ARG_POINTER);
-  grpc_lb_addresses* addresses =
-      static_cast<grpc_lb_addresses*>(arg->value.pointer.p);
+  grpc_core::ServerAddressList* addresses =
+      grpc_core::FindServerAddressListChannelArg(args);
+  GPR_ASSERT(addresses != nullptr);
   grpc_core::RefCountedPtr<grpc_core::TargetAuthorityTable>
-      target_authority_table = grpc_core::CreateTargetAuthorityTable(addresses);
+      target_authority_table =
+          grpc_core::CreateTargetAuthorityTable(*addresses);
   args_to_add[num_args_to_add++] =
       grpc_core::CreateTargetAuthorityTableChannelArg(
           target_authority_table.get());

src/core/ext/filters/client_channel/lb_policy/xds/xds_load_balancer_api.h

@@ -25,7 +25,7 @@
 
 #include "src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h"
 #include "src/core/ext/filters/client_channel/lb_policy/xds/xds_client_stats.h"
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
 
 #define XDS_SERVICE_NAME_MAX_LENGTH 128
 

src/core/ext/filters/client_channel/lb_policy_factory.cc

@@ -1,163 +0,0 @@
-/*
- *
- * Copyright 2015 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-#include <grpc/support/port_platform.h>
-
-#include <string.h>
-
-#include <grpc/support/alloc.h>
-#include <grpc/support/string_util.h>
-
-#include "src/core/lib/channel/channel_args.h"
-
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
-#include "src/core/ext/filters/client_channel/parse_address.h"
-
-grpc_lb_addresses* grpc_lb_addresses_create(
-    size_t num_addresses, const grpc_lb_user_data_vtable* user_data_vtable) {
-  grpc_lb_addresses* addresses =
-      static_cast<grpc_lb_addresses*>(gpr_zalloc(sizeof(grpc_lb_addresses)));
-  addresses->num_addresses = num_addresses;
-  addresses->user_data_vtable = user_data_vtable;
-  const size_t addresses_size = sizeof(grpc_lb_address) * num_addresses;
-  addresses->addresses =
-      static_cast<grpc_lb_address*>(gpr_zalloc(addresses_size));
-  return addresses;
-}
-
-grpc_lb_addresses* grpc_lb_addresses_copy(const grpc_lb_addresses* addresses) {
-  grpc_lb_addresses* new_addresses = grpc_lb_addresses_create(
-      addresses->num_addresses, addresses->user_data_vtable);
-  memcpy(new_addresses->addresses, addresses->addresses,
-         sizeof(grpc_lb_address) * addresses->num_addresses);
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    if (new_addresses->addresses[i].balancer_name != nullptr) {
-      new_addresses->addresses[i].balancer_name =
-          gpr_strdup(new_addresses->addresses[i].balancer_name);
-    }
-    if (new_addresses->addresses[i].user_data != nullptr) {
-      new_addresses->addresses[i].user_data = addresses->user_data_vtable->copy(
-          new_addresses->addresses[i].user_data);
-    }
-  }
-  return new_addresses;
-}
-
-void grpc_lb_addresses_set_address(grpc_lb_addresses* addresses, size_t index,
-                                   const void* address, size_t address_len,
-                                   bool is_balancer, const char* balancer_name,
-                                   void* user_data) {
-  GPR_ASSERT(index < addresses->num_addresses);
-  if (user_data != nullptr) GPR_ASSERT(addresses->user_data_vtable != nullptr);
-  grpc_lb_address* target = &addresses->addresses[index];
-  memcpy(target->address.addr, address, address_len);
-  target->address.len = static_cast<socklen_t>(address_len);
-  target->is_balancer = is_balancer;
-  target->balancer_name = gpr_strdup(balancer_name);
-  target->user_data = user_data;
-}
-
-bool grpc_lb_addresses_set_address_from_uri(grpc_lb_addresses* addresses,
-                                            size_t index, const grpc_uri* uri,
-                                            bool is_balancer,
-                                            const char* balancer_name,
-                                            void* user_data) {
-  grpc_resolved_address address;
-  if (!grpc_parse_uri(uri, &address)) return false;
-  grpc_lb_addresses_set_address(addresses, index, address.addr, address.len,
-                                is_balancer, balancer_name, user_data);
-  return true;
-}
-
-int grpc_lb_addresses_cmp(const grpc_lb_addresses* addresses1,
-                          const grpc_lb_addresses* addresses2) {
-  if (addresses1->num_addresses > addresses2->num_addresses) return 1;
-  if (addresses1->num_addresses < addresses2->num_addresses) return -1;
-  if (addresses1->user_data_vtable > addresses2->user_data_vtable) return 1;
-  if (addresses1->user_data_vtable < addresses2->user_data_vtable) return -1;
-  for (size_t i = 0; i < addresses1->num_addresses; ++i) {
-    const grpc_lb_address* target1 = &addresses1->addresses[i];
-    const grpc_lb_address* target2 = &addresses2->addresses[i];
-    if (target1->address.len > target2->address.len) return 1;
-    if (target1->address.len < target2->address.len) return -1;
-    int retval = memcmp(target1->address.addr, target2->address.addr,
-                        target1->address.len);
-    if (retval != 0) return retval;
-    if (target1->is_balancer > target2->is_balancer) return 1;
-    if (target1->is_balancer < target2->is_balancer) return -1;
-    const char* balancer_name1 =
-        target1->balancer_name != nullptr ? target1->balancer_name : "";
-    const char* balancer_name2 =
-        target2->balancer_name != nullptr ? target2->balancer_name : "";
-    retval = strcmp(balancer_name1, balancer_name2);
-    if (retval != 0) return retval;
-    if (addresses1->user_data_vtable != nullptr) {
-      retval = addresses1->user_data_vtable->cmp(target1->user_data,
-                                                 target2->user_data);
-      if (retval != 0) return retval;
-    }
-  }
-  return 0;
-}
-
-void grpc_lb_addresses_destroy(grpc_lb_addresses* addresses) {
-  for (size_t i = 0; i < addresses->num_addresses; ++i) {
-    gpr_free(addresses->addresses[i].balancer_name);
-    if (addresses->addresses[i].user_data != nullptr) {
-      addresses->user_data_vtable->destroy(addresses->addresses[i].user_data);
-    }
-  }
-  gpr_free(addresses->addresses);
-  gpr_free(addresses);
-}
-
-static void* lb_addresses_copy(void* addresses) {
-  return grpc_lb_addresses_copy(static_cast<grpc_lb_addresses*>(addresses));
-}
-static void lb_addresses_destroy(void* addresses) {
-  grpc_lb_addresses_destroy(static_cast<grpc_lb_addresses*>(addresses));
-}
-static int lb_addresses_cmp(void* addresses1, void* addresses2) {
-  return grpc_lb_addresses_cmp(static_cast<grpc_lb_addresses*>(addresses1),
-                               static_cast<grpc_lb_addresses*>(addresses2));
-}
-static const grpc_arg_pointer_vtable lb_addresses_arg_vtable = {
-    lb_addresses_copy, lb_addresses_destroy, lb_addresses_cmp};
-
-grpc_arg grpc_lb_addresses_create_channel_arg(
-    const grpc_lb_addresses* addresses) {
-  return grpc_channel_arg_pointer_create(
-      (char*)GRPC_ARG_LB_ADDRESSES, (void*)addresses, &lb_addresses_arg_vtable);
-}
-
-grpc_lb_addresses* grpc_lb_addresses_find_channel_arg(
-    const grpc_channel_args* channel_args) {
-  const grpc_arg* lb_addresses_arg =
-      grpc_channel_args_find(channel_args, GRPC_ARG_LB_ADDRESSES);
-  if (lb_addresses_arg == nullptr || lb_addresses_arg->type != GRPC_ARG_POINTER)
-    return nullptr;
-  return static_cast<grpc_lb_addresses*>(lb_addresses_arg->value.pointer.p);
-}
-
-bool grpc_lb_addresses_contains_balancer_address(
-    const grpc_lb_addresses& addresses) {
-  for (size_t i = 0; i < addresses.num_addresses; ++i) {
-    if (addresses.addresses[i].is_balancer) return true;
-  }
-  return false;
-}

src/core/ext/filters/client_channel/lb_policy_factory.h

@@ -21,91 +21,9 @@
 
 #include <grpc/support/port_platform.h>
 
-#include "src/core/lib/iomgr/resolve_address.h"
-
-#include "src/core/ext/filters/client_channel/client_channel_factory.h"
 #include "src/core/ext/filters/client_channel/lb_policy.h"
-#include "src/core/lib/uri/uri_parser.h"
-
-//
-// representation of an LB address
-//
-
-// Channel arg key for grpc_lb_addresses.
-#define GRPC_ARG_LB_ADDRESSES "grpc.lb_addresses"
-
-/** A resolved address alongside any LB related information associated with it.
- * \a user_data, if not NULL, contains opaque data meant to be consumed by the
- * gRPC LB policy. Note that no all LB policies support \a user_data as input.
- * Those who don't will simply ignore it and will correspondingly return NULL in
- * their namesake pick() output argument. */
-// TODO(roth): Once we figure out a better way of handling user_data in
-// LB policies, convert these structs to C++ classes.
-typedef struct grpc_lb_address {
-  grpc_resolved_address address;
-  bool is_balancer;
-  char* balancer_name; /* For secure naming. */
-  void* user_data;
-} grpc_lb_address;
-
-typedef struct grpc_lb_user_data_vtable {
-  void* (*copy)(void*);
-  void (*destroy)(void*);
-  int (*cmp)(void*, void*);
-} grpc_lb_user_data_vtable;
-
-typedef struct grpc_lb_addresses {
-  size_t num_addresses;
-  grpc_lb_address* addresses;
-  const grpc_lb_user_data_vtable* user_data_vtable;
-} grpc_lb_addresses;
-
-/** Returns a grpc_addresses struct with enough space for
-    \a num_addresses addresses.  The \a user_data_vtable argument may be
-    NULL if no user data will be added. */
-grpc_lb_addresses* grpc_lb_addresses_create(
-    size_t num_addresses, const grpc_lb_user_data_vtable* user_data_vtable);
-
-/** Creates a copy of \a addresses. */
-grpc_lb_addresses* grpc_lb_addresses_copy(const grpc_lb_addresses* addresses);
-
-/** Sets the value of the address at index \a index of \a addresses.
- * \a address is a socket address of length \a address_len. */
-void grpc_lb_addresses_set_address(grpc_lb_addresses* addresses, size_t index,
-                                   const void* address, size_t address_len,
-                                   bool is_balancer, const char* balancer_name,
-                                   void* user_data);
-
-/** Sets the value of the address at index \a index of \a addresses from \a uri.
- * Returns true upon success, false otherwise. */
-bool grpc_lb_addresses_set_address_from_uri(grpc_lb_addresses* addresses,
-                                            size_t index, const grpc_uri* uri,
-                                            bool is_balancer,
-                                            const char* balancer_name,
-                                            void* user_data);
-
-/** Compares \a addresses1 and \a addresses2. */
-int grpc_lb_addresses_cmp(const grpc_lb_addresses* addresses1,
-                          const grpc_lb_addresses* addresses2);
-
-/** Destroys \a addresses. */
-void grpc_lb_addresses_destroy(grpc_lb_addresses* addresses);
-
-/** Returns a channel arg containing \a addresses. */
-grpc_arg grpc_lb_addresses_create_channel_arg(
-    const grpc_lb_addresses* addresses);
-
-/** Returns the \a grpc_lb_addresses instance in \a channel_args or NULL */
-grpc_lb_addresses* grpc_lb_addresses_find_channel_arg(
-    const grpc_channel_args* channel_args);
-
-// Returns true if addresses contains at least one balancer address.
-bool grpc_lb_addresses_contains_balancer_address(
-    const grpc_lb_addresses& addresses);
-
-//
-// LB policy factory
-//
+#include "src/core/lib/gprpp/abstract.h"
+#include "src/core/lib/gprpp/orphanable.h"
 
 namespace grpc_core {
 

src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc

@@ -33,6 +33,7 @@
 #include "src/core/ext/filters/client_channel/lb_policy_registry.h"
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/backoff/backoff.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/env.h"
@@ -117,7 +118,7 @@ class AresDnsResolver : public Resolver {
   /// retry backoff state
   BackOff backoff_;
   /// currently resolving addresses
-  grpc_lb_addresses* lb_addresses_ = nullptr;
+  UniquePtr<ServerAddressList> addresses_;
   /// currently resolving service config
   char* service_config_json_ = nullptr;
   // has shutdown been initiated
@@ -314,13 +315,13 @@ void AresDnsResolver::OnResolvedLocked(void* arg, grpc_error* error) {
   r->resolving_ = false;
   gpr_free(r->pending_request_);
   r->pending_request_ = nullptr;
-  if (r->lb_addresses_ != nullptr) {
+  if (r->addresses_ != nullptr) {
     static const char* args_to_remove[1];
     size_t num_args_to_remove = 0;
     grpc_arg args_to_add[2];
     size_t num_args_to_add = 0;
     args_to_add[num_args_to_add++] =
-        grpc_lb_addresses_create_channel_arg(r->lb_addresses_);
+        CreateServerAddressListChannelArg(r->addresses_.get());
     char* service_config_string = nullptr;
     if (r->service_config_json_ != nullptr) {
       service_config_string = ChooseServiceConfig(r->service_config_json_);
@@ -337,7 +338,7 @@ void AresDnsResolver::OnResolvedLocked(void* arg, grpc_error* error) {
         r->channel_args_, args_to_remove, num_args_to_remove, args_to_add,
         num_args_to_add);
     gpr_free(service_config_string);
-    grpc_lb_addresses_destroy(r->lb_addresses_);
+    r->addresses_.reset();
     // Reset backoff state so that we start from the beginning when the
     // next request gets triggered.
     r->backoff_.Reset();
@@ -412,11 +413,10 @@ void AresDnsResolver::StartResolvingLocked() {
   self.release();
   GPR_ASSERT(!resolving_);
   resolving_ = true;
-  lb_addresses_ = nullptr;
   service_config_json_ = nullptr;
   pending_request_ = grpc_dns_lookup_ares_locked(
       dns_server_, name_to_resolve_, kDefaultPort, interested_parties_,
-      &on_resolved_, &lb_addresses_, true /* check_grpclb */,
+      &on_resolved_, &addresses_, true /* check_grpclb */,
       request_service_config_ ? &service_config_json_ : nullptr,
       query_timeout_ms_, combiner());
   last_resolution_timestamp_ = grpc_core::ExecCtx::Get()->Now();

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc

@@ -31,6 +31,7 @@
 #include <grpc/support/time.h>
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
 #include "src/core/lib/gpr/string.h"
+#include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/iomgr/timer.h"

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc

@@ -37,12 +37,16 @@
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h"
 #include "src/core/lib/gpr/host_port.h"
 #include "src/core/lib/gpr/string.h"
+#include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/error.h"
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/nameser.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 
+using grpc_core::ServerAddress;
+using grpc_core::ServerAddressList;
+
 static gpr_once g_basic_init = GPR_ONCE_INIT;
 static gpr_mu g_init_mu;
 
@@ -58,7 +62,7 @@ struct grpc_ares_request {
   /** closure to call when the request completes */
   grpc_closure* on_done;
   /** the pointer to receive the resolved addresses */
-  grpc_lb_addresses** lb_addrs_out;
+  grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses_out;
   /** the pointer to receive the service config in JSON */
   char** service_config_json_out;
   /** the evernt driver used by this request */
@@ -87,12 +91,11 @@ typedef struct grpc_ares_hostbyname_request {
 
 static void do_basic_init(void) { gpr_mu_init(&g_init_mu); }
 
-static void log_address_sorting_list(grpc_lb_addresses* lb_addrs,
+static void log_address_sorting_list(const ServerAddressList& addresses,
                                      const char* input_output_str) {
-  for (size_t i = 0; i < lb_addrs->num_addresses; i++) {
+  for (size_t i = 0; i < addresses.size(); i++) {
     char* addr_str;
-    if (grpc_sockaddr_to_string(&addr_str, &lb_addrs->addresses[i].address,
-                                true)) {
+    if (grpc_sockaddr_to_string(&addr_str, &addresses[i].address(), true)) {
       gpr_log(GPR_DEBUG, "c-ares address sorting: %s[%" PRIuPTR "]=%s",
               input_output_str, i, addr_str);
       gpr_free(addr_str);
@@ -104,29 +107,28 @@ static void log_address_sorting_list(grpc_lb_addresses* lb_addrs,
   }
 }
 
-void grpc_cares_wrapper_address_sorting_sort(grpc_lb_addresses* lb_addrs) {
+void grpc_cares_wrapper_address_sorting_sort(ServerAddressList* addresses) {
   if (grpc_trace_cares_address_sorting.enabled()) {
-    log_address_sorting_list(lb_addrs, "input");
+    log_address_sorting_list(*addresses, "input");
   }
   address_sorting_sortable* sortables = (address_sorting_sortable*)gpr_zalloc(
-      sizeof(address_sorting_sortable) * lb_addrs->num_addresses);
-  for (size_t i = 0; i < lb_addrs->num_addresses; i++) {
-    sortables[i].user_data = &lb_addrs->addresses[i];
-    memcpy(&sortables[i].dest_addr.addr, &lb_addrs->addresses[i].address.addr,
-           lb_addrs->addresses[i].address.len);
-    sortables[i].dest_addr.len = lb_addrs->addresses[i].address.len;
+      sizeof(address_sorting_sortable) * addresses->size());
+  for (size_t i = 0; i < addresses->size(); ++i) {
+    sortables[i].user_data = &(*addresses)[i];
+    memcpy(&sortables[i].dest_addr.addr, &(*addresses)[i].address().addr,
+           (*addresses)[i].address().len);
+    sortables[i].dest_addr.len = (*addresses)[i].address().len;
   }
-  address_sorting_rfc_6724_sort(sortables, lb_addrs->num_addresses);
-  grpc_lb_address* sorted_lb_addrs = (grpc_lb_address*)gpr_zalloc(
-      sizeof(grpc_lb_address) * lb_addrs->num_addresses);
-  for (size_t i = 0; i < lb_addrs->num_addresses; i++) {
-    sorted_lb_addrs[i] = *(grpc_lb_address*)sortables[i].user_data;
+  address_sorting_rfc_6724_sort(sortables, addresses->size());
+  ServerAddressList sorted;
+  sorted.reserve(addresses->size());
+  for (size_t i = 0; i < addresses->size(); ++i) {
+    sorted.emplace_back(*static_cast<ServerAddress*>(sortables[i].user_data));
   }
   gpr_free(sortables);
-  gpr_free(lb_addrs->addresses);
-  lb_addrs->addresses = sorted_lb_addrs;
+  *addresses = std::move(sorted);
   if (grpc_trace_cares_address_sorting.enabled()) {
-    log_address_sorting_list(lb_addrs, "output");
+    log_address_sorting_list(*addresses, "output");
   }
 }
 
@@ -145,9 +147,9 @@ void grpc_ares_complete_request_locked(grpc_ares_request* r) {
   /* Invoke on_done callback and destroy the
      request */
   r->ev_driver = nullptr;
-  grpc_lb_addresses* lb_addrs = *(r->lb_addrs_out);
-  if (lb_addrs != nullptr) {
-    grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  ServerAddressList* addresses = r->addresses_out->get();
+  if (addresses != nullptr) {
+    grpc_cares_wrapper_address_sorting_sort(addresses);
   }
   GRPC_CLOSURE_SCHED(r->on_done, r->error);
 }
@@ -181,33 +183,30 @@ static void on_hostbyname_done_locked(void* arg, int status, int timeouts,
     GRPC_ERROR_UNREF(r->error);
     r->error = GRPC_ERROR_NONE;
     r->success = true;
-    grpc_lb_addresses** lb_addresses = r->lb_addrs_out;
-    if (*lb_addresses == nullptr) {
-      *lb_addresses = grpc_lb_addresses_create(0, nullptr);
-    }
-    size_t prev_naddr = (*lb_addresses)->num_addresses;
-    size_t i;
-    for (i = 0; hostent->h_addr_list[i] != nullptr; i++) {
+    if (*r->addresses_out == nullptr) {
+      *r->addresses_out = grpc_core::MakeUnique<ServerAddressList>();
     }
-    (*lb_addresses)->num_addresses += i;
-    (*lb_addresses)->addresses = static_cast<grpc_lb_address*>(
-        gpr_realloc((*lb_addresses)->addresses,
-                    sizeof(grpc_lb_address) * (*lb_addresses)->num_addresses));
-    for (i = prev_naddr; i < (*lb_addresses)->num_addresses; i++) {
+    ServerAddressList& addresses = **r->addresses_out;
+    for (size_t i = 0; hostent->h_addr_list[i] != nullptr; ++i) {
+      grpc_core::InlinedVector<grpc_arg, 2> args_to_add;
+      if (hr->is_balancer) {
+        args_to_add.emplace_back(grpc_channel_arg_integer_create(
+            const_cast<char*>(GRPC_ARG_ADDRESS_IS_BALANCER), 1));
+        args_to_add.emplace_back(grpc_channel_arg_string_create(
+            const_cast<char*>(GRPC_ARG_ADDRESS_BALANCER_NAME), hr->host));
+      }
+      grpc_channel_args* args = grpc_channel_args_copy_and_add(
+          nullptr, args_to_add.data(), args_to_add.size());
       switch (hostent->h_addrtype) {
         case AF_INET6: {
           size_t addr_len = sizeof(struct sockaddr_in6);
           struct sockaddr_in6 addr;
           memset(&addr, 0, addr_len);
-          memcpy(&addr.sin6_addr, hostent->h_addr_list[i - prev_naddr],
+          memcpy(&addr.sin6_addr, hostent->h_addr_list[i],
                  sizeof(struct in6_addr));
           addr.sin6_family = static_cast<unsigned char>(hostent->h_addrtype);
           addr.sin6_port = hr->port;
-          grpc_lb_addresses_set_address(
-              *lb_addresses, i, &addr, addr_len,
-              hr->is_balancer /* is_balancer */,
-              hr->is_balancer ? hr->host : nullptr /* balancer_name */,
-              nullptr /* user_data */);
+          addresses.emplace_back(&addr, addr_len, args);
           char output[INET6_ADDRSTRLEN];
           ares_inet_ntop(AF_INET6, &addr.sin6_addr, output, INET6_ADDRSTRLEN);
           gpr_log(GPR_DEBUG,
@@ -220,15 +219,11 @@ static void on_hostbyname_done_locked(void* arg, int status, int timeouts,
           size_t addr_len = sizeof(struct sockaddr_in);
           struct sockaddr_in addr;
           memset(&addr, 0, addr_len);
-          memcpy(&addr.sin_addr, hostent->h_addr_list[i - prev_naddr],
+          memcpy(&addr.sin_addr, hostent->h_addr_list[i],
                  sizeof(struct in_addr));
           addr.sin_family = static_cast<unsigned char>(hostent->h_addrtype);
           addr.sin_port = hr->port;
-          grpc_lb_addresses_set_address(
-              *lb_addresses, i, &addr, addr_len,
-              hr->is_balancer /* is_balancer */,
-              hr->is_balancer ? hr->host : nullptr /* balancer_name */,
-              nullptr /* user_data */);
+          addresses.emplace_back(&addr, addr_len, args);
           char output[INET_ADDRSTRLEN];
           ares_inet_ntop(AF_INET, &addr.sin_addr, output, INET_ADDRSTRLEN);
           gpr_log(GPR_DEBUG,
@@ -467,11 +462,10 @@ error_cleanup:
   gpr_free(port);
 }
 
-static bool inner_resolve_as_ip_literal_locked(const char* name,
-                                               const char* default_port,
-                                               grpc_lb_addresses** addrs,
-                                               char** host, char** port,
-                                               char** hostport) {
+static bool inner_resolve_as_ip_literal_locked(
+    const char* name, const char* default_port,
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs, char** host,
+    char** port, char** hostport) {
   gpr_split_host_port(name, host, port);
   if (*host == nullptr) {
     gpr_log(GPR_ERROR,
@@ -495,18 +489,16 @@ static bool inner_resolve_as_ip_literal_locked(const char* name,
   if (grpc_parse_ipv4_hostport(*hostport, &addr, false /* log errors */) ||
       grpc_parse_ipv6_hostport(*hostport, &addr, false /* log errors */)) {
     GPR_ASSERT(*addrs == nullptr);
-    *addrs = grpc_lb_addresses_create(1, nullptr);
-    grpc_lb_addresses_set_address(
-        *addrs, 0, addr.addr, addr.len, false /* is_balancer */,
-        nullptr /* balancer_name */, nullptr /* user_data */);
+    *addrs = grpc_core::MakeUnique<ServerAddressList>();
+    (*addrs)->emplace_back(addr.addr, addr.len, nullptr /* args */);
     return true;
   }
   return false;
 }
 
-static bool resolve_as_ip_literal_locked(const char* name,
-                                         const char* default_port,
-                                         grpc_lb_addresses** addrs) {
+static bool resolve_as_ip_literal_locked(
+    const char* name, const char* default_port,
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs) {
   char* host = nullptr;
   char* port = nullptr;
   char* hostport = nullptr;
@@ -521,13 +513,14 @@ static bool resolve_as_ip_literal_locked(const char* name,
 static grpc_ares_request* grpc_dns_lookup_ares_locked_impl(
     const char* dns_server, const char* name, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** addrs, bool check_grpclb, char** service_config_json,
-    int query_timeout_ms, grpc_combiner* combiner) {
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
+    grpc_combiner* combiner) {
   grpc_ares_request* r =
       static_cast<grpc_ares_request*>(gpr_zalloc(sizeof(grpc_ares_request)));
   r->ev_driver = nullptr;
   r->on_done = on_done;
-  r->lb_addrs_out = addrs;
+  r->addresses_out = addrs;
   r->service_config_json_out = service_config_json;
   r->success = false;
   r->error = GRPC_ERROR_NONE;
@@ -553,8 +546,8 @@ static grpc_ares_request* grpc_dns_lookup_ares_locked_impl(
 grpc_ares_request* (*grpc_dns_lookup_ares_locked)(
     const char* dns_server, const char* name, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** addrs, bool check_grpclb, char** service_config_json,
-    int query_timeout_ms,
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
     grpc_combiner* combiner) = grpc_dns_lookup_ares_locked_impl;
 
 static void grpc_cancel_ares_request_locked_impl(grpc_ares_request* r) {
@@ -599,8 +592,8 @@ typedef struct grpc_resolve_address_ares_request {
   grpc_combiner* combiner;
   /** the pointer to receive the resolved addresses */
   grpc_resolved_addresses** addrs_out;
-  /** currently resolving lb addresses */
-  grpc_lb_addresses* lb_addrs;
+  /** currently resolving addresses */
+  grpc_core::UniquePtr<ServerAddressList> addresses;
   /** closure to call when the resolve_address_ares request completes */
   grpc_closure* on_resolve_address_done;
   /** a closure wrapping on_resolve_address_done, which should be invoked when
@@ -613,7 +606,7 @@ typedef struct grpc_resolve_address_ares_request {
   /* pollset_set to be driven by */
   grpc_pollset_set* interested_parties;
   /* underlying ares_request that the query is performed on */
-  grpc_ares_request* ares_request;
+  grpc_ares_request* ares_request = nullptr;
 } grpc_resolve_address_ares_request;
 
 static void on_dns_lookup_done_locked(void* arg, grpc_error* error) {
@@ -621,25 +614,24 @@ static void on_dns_lookup_done_locked(void* arg, grpc_error* error) {
       static_cast<grpc_resolve_address_ares_request*>(arg);
   gpr_free(r->ares_request);
   grpc_resolved_addresses** resolved_addresses = r->addrs_out;
-  if (r->lb_addrs == nullptr || r->lb_addrs->num_addresses == 0) {
+  if (r->addresses == nullptr || r->addresses->empty()) {
     *resolved_addresses = nullptr;
   } else {
     *resolved_addresses = static_cast<grpc_resolved_addresses*>(
         gpr_zalloc(sizeof(grpc_resolved_addresses)));
-    (*resolved_addresses)->naddrs = r->lb_addrs->num_addresses;
+    (*resolved_addresses)->naddrs = r->addresses->size();
     (*resolved_addresses)->addrs =
         static_cast<grpc_resolved_address*>(gpr_zalloc(
             sizeof(grpc_resolved_address) * (*resolved_addresses)->naddrs));
-    for (size_t i = 0; i < (*resolved_addresses)->naddrs; i++) {
-      GPR_ASSERT(!r->lb_addrs->addresses[i].is_balancer);
-      memcpy(&(*resolved_addresses)->addrs[i],
-             &r->lb_addrs->addresses[i].address, sizeof(grpc_resolved_address));
+    for (size_t i = 0; i < (*resolved_addresses)->naddrs; ++i) {
+      GPR_ASSERT(!(*r->addresses)[i].IsBalancer());
+      memcpy(&(*resolved_addresses)->addrs[i], &(*r->addresses)[i].address(),
+             sizeof(grpc_resolved_address));
     }
   }
   GRPC_CLOSURE_SCHED(r->on_resolve_address_done, GRPC_ERROR_REF(error));
-  if (r->lb_addrs != nullptr) grpc_lb_addresses_destroy(r->lb_addrs);
   GRPC_COMBINER_UNREF(r->combiner, "on_dns_lookup_done_cb");
-  gpr_free(r);
+  grpc_core::Delete(r);
 }
 
 static void grpc_resolve_address_invoke_dns_lookup_ares_locked(
@@ -648,7 +640,7 @@ static void grpc_resolve_address_invoke_dns_lookup_ares_locked(
       static_cast<grpc_resolve_address_ares_request*>(arg);
   r->ares_request = grpc_dns_lookup_ares_locked(
       nullptr /* dns_server */, r->name, r->default_port, r->interested_parties,
-      &r->on_dns_lookup_done_locked, &r->lb_addrs, false /* check_grpclb */,
+      &r->on_dns_lookup_done_locked, &r->addresses, false /* check_grpclb */,
       nullptr /* service_config_json */, GRPC_DNS_ARES_DEFAULT_QUERY_TIMEOUT_MS,
       r->combiner);
 }
@@ -659,8 +651,7 @@ static void grpc_resolve_address_ares_impl(const char* name,
                                            grpc_closure* on_done,
                                            grpc_resolved_addresses** addrs) {
   grpc_resolve_address_ares_request* r =
-      static_cast<grpc_resolve_address_ares_request*>(
-          gpr_zalloc(sizeof(grpc_resolve_address_ares_request)));
+      grpc_core::New<grpc_resolve_address_ares_request>();
   r->combiner = grpc_combiner_create();
   r->addrs_out = addrs;
   r->on_resolve_address_done = on_done;

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h

@@ -21,7 +21,7 @@
 
 #include <grpc/support/port_platform.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/iomgr/iomgr.h"
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/iomgr/resolve_address.h"
@@ -61,8 +61,9 @@ extern void (*grpc_resolve_address_ares)(const char* name,
 extern grpc_ares_request* (*grpc_dns_lookup_ares_locked)(
     const char* dns_server, const char* name, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** addresses, bool check_grpclb,
-    char** service_config_json, int query_timeout_ms, grpc_combiner* combiner);
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
+    grpc_combiner* combiner);
 
 /* Cancel the pending grpc_ares_request \a request */
 extern void (*grpc_cancel_ares_request_locked)(grpc_ares_request* request);
@@ -89,10 +90,12 @@ bool grpc_ares_query_ipv6();
  * Returns a bool indicating whether or not such an action was performed.
  * See https://github.com/grpc/grpc/issues/15158. */
 bool grpc_ares_maybe_resolve_localhost_manually_locked(
-    const char* name, const char* default_port, grpc_lb_addresses** addrs);
+    const char* name, const char* default_port,
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs);
 
 /* Sorts destinations in lb_addrs according to RFC 6724. */
-void grpc_cares_wrapper_address_sorting_sort(grpc_lb_addresses* lb_addrs);
+void grpc_cares_wrapper_address_sorting_sort(
+    grpc_core::ServerAddressList* addresses);
 
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_WRAPPER_H \
         */

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc

@@ -29,16 +29,17 @@ struct grpc_ares_request {
 static grpc_ares_request* grpc_dns_lookup_ares_locked_impl(
     const char* dns_server, const char* name, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** addrs, bool check_grpclb, char** service_config_json,
-    int query_timeout_ms, grpc_combiner* combiner) {
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
+    grpc_combiner* combiner) {
   return NULL;
 }
 
 grpc_ares_request* (*grpc_dns_lookup_ares_locked)(
     const char* dns_server, const char* name, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** addrs, bool check_grpclb, char** service_config_json,
-    int query_timeout_ms,
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
     grpc_combiner* combiner) = grpc_dns_lookup_ares_locked_impl;
 
 static void grpc_cancel_ares_request_locked_impl(grpc_ares_request* r) {}

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc

@@ -27,7 +27,8 @@
 bool grpc_ares_query_ipv6() { return grpc_ipv6_loopback_available(); }
 
 bool grpc_ares_maybe_resolve_localhost_manually_locked(
-    const char* name, const char* default_port, grpc_lb_addresses** addrs) {
+    const char* name, const char* default_port,
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs) {
   return false;
 }
 

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc

@@ -23,9 +23,9 @@
 
 #include <grpc/support/string_util.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/gpr/host_port.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/socket_windows.h"
@@ -33,8 +33,9 @@
 bool grpc_ares_query_ipv6() { return grpc_ipv6_loopback_available(); }
 
 static bool inner_maybe_resolve_localhost_manually_locked(
-    const char* name, const char* default_port, grpc_lb_addresses** addrs,
-    char** host, char** port) {
+    const char* name, const char* default_port,
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs, char** host,
+    char** port) {
   gpr_split_host_port(name, host, port);
   if (*host == nullptr) {
     gpr_log(GPR_ERROR,
@@ -55,7 +56,7 @@ static bool inner_maybe_resolve_localhost_manually_locked(
   }
   if (gpr_stricmp(*host, "localhost") == 0) {
     GPR_ASSERT(*addrs == nullptr);
-    *addrs = grpc_lb_addresses_create(2, nullptr);
+    *addrs = grpc_core::MakeUnique<grpc_core::ServerAddressList>();
     uint16_t numeric_port = grpc_strhtons(*port);
     // Append the ipv6 loopback address.
     struct sockaddr_in6 ipv6_loopback_addr;
@@ -63,10 +64,8 @@ static bool inner_maybe_resolve_localhost_manually_locked(
     ((char*)&ipv6_loopback_addr.sin6_addr)[15] = 1;
     ipv6_loopback_addr.sin6_family = AF_INET6;
     ipv6_loopback_addr.sin6_port = numeric_port;
-    grpc_lb_addresses_set_address(
-        *addrs, 0, &ipv6_loopback_addr, sizeof(ipv6_loopback_addr),
-        false /* is_balancer */, nullptr /* balancer_name */,
-        nullptr /* user_data */);
+    (*addrs)->emplace_back(&ipv6_loopback_addr, sizeof(ipv6_loopback_addr),
+                           nullptr /* args */);
     // Append the ipv4 loopback address.
     struct sockaddr_in ipv4_loopback_addr;
     memset(&ipv4_loopback_addr, 0, sizeof(ipv4_loopback_addr));
@@ -74,19 +73,18 @@ static bool inner_maybe_resolve_localhost_manually_locked(
     ((char*)&ipv4_loopback_addr.sin_addr)[3] = 0x01;
     ipv4_loopback_addr.sin_family = AF_INET;
     ipv4_loopback_addr.sin_port = numeric_port;
-    grpc_lb_addresses_set_address(
-        *addrs, 1, &ipv4_loopback_addr, sizeof(ipv4_loopback_addr),
-        false /* is_balancer */, nullptr /* balancer_name */,
-        nullptr /* user_data */);
+    (*addrs)->emplace_back(&ipv4_loopback_addr, sizeof(ipv4_loopback_addr),
+                           nullptr /* args */);
     // Let the address sorter figure out which one should be tried first.
-    grpc_cares_wrapper_address_sorting_sort(*addrs);
+    grpc_cares_wrapper_address_sorting_sort(addrs->get());
     return true;
   }
   return false;
 }
 
 bool grpc_ares_maybe_resolve_localhost_manually_locked(
-    const char* name, const char* default_port, grpc_lb_addresses** addrs) {
+    const char* name, const char* default_port,
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs) {
   char* host = nullptr;
   char* port = nullptr;
   bool out = inner_maybe_resolve_localhost_manually_locked(name, default_port,

src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc

@@ -26,8 +26,8 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/time.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_registry.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/backoff/backoff.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/env.h"
@@ -198,18 +198,14 @@ void NativeDnsResolver::OnResolvedLocked(void* arg, grpc_error* error) {
       grpc_error_set_str(error, GRPC_ERROR_STR_TARGET_ADDRESS,
                          grpc_slice_from_copied_string(r->name_to_resolve_));
   if (r->addresses_ != nullptr) {
-    grpc_lb_addresses* addresses = grpc_lb_addresses_create(
-        r->addresses_->naddrs, nullptr /* user_data_vtable */);
+    ServerAddressList addresses;
     for (size_t i = 0; i < r->addresses_->naddrs; ++i) {
-      grpc_lb_addresses_set_address(
-          addresses, i, &r->addresses_->addrs[i].addr,
-          r->addresses_->addrs[i].len, false /* is_balancer */,
-          nullptr /* balancer_name */, nullptr /* user_data */);
+      addresses.emplace_back(&r->addresses_->addrs[i].addr,
+                             r->addresses_->addrs[i].len, nullptr /* args */);
     }
-    grpc_arg new_arg = grpc_lb_addresses_create_channel_arg(addresses);
+    grpc_arg new_arg = CreateServerAddressListChannelArg(&addresses);
     result = grpc_channel_args_copy_and_add(r->channel_args_, &new_arg, 1);
     grpc_resolved_addresses_destroy(r->addresses_);
-    grpc_lb_addresses_destroy(addresses);
     // Reset backoff state so that we start from the beginning when the
     // next request gets triggered.
     r->backoff_.Reset();

src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc

@@ -28,12 +28,13 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/host_port.h"
 #include "src/core/lib/gpr/string.h"
+#include "src/core/lib/gpr/useful.h"
 #include "src/core/lib/iomgr/closure.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/resolve_address.h"

src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h

@@ -19,10 +19,9 @@
 
 #include <grpc/support/port_platform.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gprpp/ref_counted.h"
-#include "src/core/lib/uri/uri_parser.h"
+#include "src/core/lib/iomgr/error.h"
 
 #define GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR \
   "grpc.fake_resolver.response_generator"

src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc

@@ -26,9 +26,9 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/host_port.h"
 #include "src/core/lib/gpr/string.h"
@@ -45,7 +45,8 @@ namespace {
 class SockaddrResolver : public Resolver {
  public:
   /// Takes ownership of \a addresses.
-  SockaddrResolver(const ResolverArgs& args, grpc_lb_addresses* addresses);
+  SockaddrResolver(const ResolverArgs& args,
+                   UniquePtr<ServerAddressList> addresses);
 
   void NextLocked(grpc_channel_args** result,
                   grpc_closure* on_complete) override;
@@ -58,7 +59,7 @@ class SockaddrResolver : public Resolver {
   void MaybeFinishNextLocked();
 
   /// the addresses that we've "resolved"
-  grpc_lb_addresses* addresses_ = nullptr;
+  UniquePtr<ServerAddressList> addresses_;
   /// channel args
   grpc_channel_args* channel_args_ = nullptr;
   /// have we published?
@@ -70,13 +71,12 @@ class SockaddrResolver : public Resolver {
 };
 
 SockaddrResolver::SockaddrResolver(const ResolverArgs& args,
-                                   grpc_lb_addresses* addresses)
+                                   UniquePtr<ServerAddressList> addresses)
     : Resolver(args.combiner),
-      addresses_(addresses),
+      addresses_(std::move(addresses)),
       channel_args_(grpc_channel_args_copy(args.args)) {}
 
 SockaddrResolver::~SockaddrResolver() {
-  grpc_lb_addresses_destroy(addresses_);
   grpc_channel_args_destroy(channel_args_);
 }
 
@@ -100,7 +100,7 @@ void SockaddrResolver::ShutdownLocked() {
 void SockaddrResolver::MaybeFinishNextLocked() {
   if (next_completion_ != nullptr && !published_) {
     published_ = true;
-    grpc_arg arg = grpc_lb_addresses_create_channel_arg(addresses_);
+    grpc_arg arg = CreateServerAddressListChannelArg(addresses_.get());
     *target_result_ = grpc_channel_args_copy_and_add(channel_args_, &arg, 1);
     GRPC_CLOSURE_SCHED(next_completion_, GRPC_ERROR_NONE);
     next_completion_ = nullptr;
@@ -127,27 +127,27 @@ OrphanablePtr<Resolver> CreateSockaddrResolver(
   grpc_slice_buffer path_parts;
   grpc_slice_buffer_init(&path_parts);
   grpc_slice_split(path_slice, ",", &path_parts);
-  grpc_lb_addresses* addresses = grpc_lb_addresses_create(
-      path_parts.count, nullptr /* user_data_vtable */);
+  auto addresses = MakeUnique<ServerAddressList>();
   bool errors_found = false;
-  for (size_t i = 0; i < addresses->num_addresses; i++) {
+  for (size_t i = 0; i < path_parts.count; i++) {
     grpc_uri ith_uri = *args.uri;
-    char* part_str = grpc_slice_to_c_string(path_parts.slices[i]);
-    ith_uri.path = part_str;
-    if (!parse(&ith_uri, &addresses->addresses[i].address)) {
+    UniquePtr<char> part_str(grpc_slice_to_c_string(path_parts.slices[i]));
+    ith_uri.path = part_str.get();
+    grpc_resolved_address addr;
+    if (!parse(&ith_uri, &addr)) {
       errors_found = true; /* GPR_TRUE */
+      break;
     }
-    gpr_free(part_str);
-    if (errors_found) break;
+    addresses->emplace_back(addr, nullptr /* args */);
   }
   grpc_slice_buffer_destroy_internal(&path_parts);
   grpc_slice_unref_internal(path_slice);
   if (errors_found) {
-    grpc_lb_addresses_destroy(addresses);
     return OrphanablePtr<Resolver>(nullptr);
   }
   // Instantiate resolver.
-  return OrphanablePtr<Resolver>(New<SockaddrResolver>(args, addresses));
+  return OrphanablePtr<Resolver>(
+      New<SockaddrResolver>(args, std::move(addresses)));
 }
 
 class IPv4ResolverFactory : public ResolverFactory {

src/core/ext/filters/client_channel/resolver_result_parsing.cc

@@ -30,9 +30,11 @@
 
 #include "src/core/ext/filters/client_channel/client_channel.h"
 #include "src/core/ext/filters/client_channel/lb_policy_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/status_util.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/gprpp/memory.h"
+#include "src/core/lib/uri/uri_parser.h"
 
 // As per the retry design, we do not allow more than 5 retry attempts.
 #define MAX_MAX_RETRY_ATTEMPTS 5
@@ -99,12 +101,18 @@ void ProcessedResolverResult::ProcessLbPolicyName(
   }
   // Special case: If at least one balancer address is present, we use
   // the grpclb policy, regardless of what the resolver has returned.
-  const grpc_arg* channel_arg =
-      grpc_channel_args_find(resolver_result, GRPC_ARG_LB_ADDRESSES);
-  if (channel_arg != nullptr && channel_arg->type == GRPC_ARG_POINTER) {
-    grpc_lb_addresses* addresses =
-        static_cast<grpc_lb_addresses*>(channel_arg->value.pointer.p);
-    if (grpc_lb_addresses_contains_balancer_address(*addresses)) {
+  const ServerAddressList* addresses =
+      FindServerAddressListChannelArg(resolver_result);
+  if (addresses != nullptr) {
+    bool found_balancer_address = false;
+    for (size_t i = 0; i < addresses->size(); ++i) {
+      const ServerAddress& address = (*addresses)[i];
+      if (address.IsBalancer()) {
+        found_balancer_address = true;
+        break;
+      }
+    }
+    if (found_balancer_address) {
       if (lb_policy_name_ != nullptr &&
           strcmp(lb_policy_name_.get(), "grpclb") != 0) {
         gpr_log(GPR_INFO,

src/core/ext/filters/client_channel/server_address.cc

@@ -0,0 +1,103 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/ext/filters/client_channel/server_address.h"
+
+#include <string.h>
+
+namespace grpc_core {
+
+//
+// ServerAddress
+//
+
+ServerAddress::ServerAddress(const grpc_resolved_address& address,
+                             grpc_channel_args* args)
+    : address_(address), args_(args) {}
+
+ServerAddress::ServerAddress(const void* address, size_t address_len,
+                             grpc_channel_args* args)
+    : args_(args) {
+  memcpy(address_.addr, address, address_len);
+  address_.len = static_cast<socklen_t>(address_len);
+}
+
+int ServerAddress::Cmp(const ServerAddress& other) const {
+  if (address_.len > other.address_.len) return 1;
+  if (address_.len < other.address_.len) return -1;
+  int retval = memcmp(address_.addr, other.address_.addr, address_.len);
+  if (retval != 0) return retval;
+  return grpc_channel_args_compare(args_, other.args_);
+}
+
+bool ServerAddress::IsBalancer() const {
+  return grpc_channel_arg_get_bool(
+      grpc_channel_args_find(args_, GRPC_ARG_ADDRESS_IS_BALANCER), false);
+}
+
+//
+// ServerAddressList
+//
+
+namespace {
+
+void* ServerAddressListCopy(void* addresses) {
+  ServerAddressList* a = static_cast<ServerAddressList*>(addresses);
+  return New<ServerAddressList>(*a);
+}
+
+void ServerAddressListDestroy(void* addresses) {
+  ServerAddressList* a = static_cast<ServerAddressList*>(addresses);
+  Delete(a);
+}
+
+int ServerAddressListCompare(void* addresses1, void* addresses2) {
+  ServerAddressList* a1 = static_cast<ServerAddressList*>(addresses1);
+  ServerAddressList* a2 = static_cast<ServerAddressList*>(addresses2);
+  if (a1->size() > a2->size()) return 1;
+  if (a1->size() < a2->size()) return -1;
+  for (size_t i = 0; i < a1->size(); ++i) {
+    int retval = (*a1)[i].Cmp((*a2)[i]);
+    if (retval != 0) return retval;
+  }
+  return 0;
+}
+
+const grpc_arg_pointer_vtable server_addresses_arg_vtable = {
+    ServerAddressListCopy, ServerAddressListDestroy, ServerAddressListCompare};
+
+}  // namespace
+
+grpc_arg CreateServerAddressListChannelArg(const ServerAddressList* addresses) {
+  return grpc_channel_arg_pointer_create(
+      const_cast<char*>(GRPC_ARG_SERVER_ADDRESS_LIST),
+      const_cast<ServerAddressList*>(addresses), &server_addresses_arg_vtable);
+}
+
+ServerAddressList* FindServerAddressListChannelArg(
+    const grpc_channel_args* channel_args) {
+  const grpc_arg* lb_addresses_arg =
+      grpc_channel_args_find(channel_args, GRPC_ARG_SERVER_ADDRESS_LIST);
+  if (lb_addresses_arg == nullptr || lb_addresses_arg->type != GRPC_ARG_POINTER)
+    return nullptr;
+  return static_cast<ServerAddressList*>(lb_addresses_arg->value.pointer.p);
+}
+
+}  // namespace grpc_core

src/core/ext/filters/client_channel/server_address.h

@@ -0,0 +1,108 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SERVER_ADDRESS_H
+#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SERVER_ADDRESS_H
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/gprpp/inlined_vector.h"
+#include "src/core/lib/iomgr/resolve_address.h"
+#include "src/core/lib/uri/uri_parser.h"
+
+// Channel arg key for ServerAddressList.
+#define GRPC_ARG_SERVER_ADDRESS_LIST "grpc.server_address_list"
+
+// Channel arg key for a bool indicating whether an address is a grpclb
+// load balancer (as opposed to a backend).
+#define GRPC_ARG_ADDRESS_IS_BALANCER "grpc.address_is_balancer"
+
+// Channel arg key for a string indicating an address's balancer name.
+#define GRPC_ARG_ADDRESS_BALANCER_NAME "grpc.address_balancer_name"
+
+namespace grpc_core {
+
+//
+// ServerAddress
+//
+
+// A server address is a grpc_resolved_address with an associated set of
+// channel args.  Any args present here will be merged into the channel
+// args when a subchannel is created for this address.
+class ServerAddress {
+ public:
+  // Takes ownership of args.
+  ServerAddress(const grpc_resolved_address& address, grpc_channel_args* args);
+  ServerAddress(const void* address, size_t address_len,
+                grpc_channel_args* args);
+
+  ~ServerAddress() { grpc_channel_args_destroy(args_); }
+
+  // Copyable.
+  ServerAddress(const ServerAddress& other)
+      : address_(other.address_), args_(grpc_channel_args_copy(other.args_)) {}
+  ServerAddress& operator=(const ServerAddress& other) {
+    address_ = other.address_;
+    grpc_channel_args_destroy(args_);
+    args_ = grpc_channel_args_copy(other.args_);
+    return *this;
+  }
+
+  // Movable.
+  ServerAddress(ServerAddress&& other)
+      : address_(other.address_), args_(other.args_) {
+    other.args_ = nullptr;
+  }
+  ServerAddress& operator=(ServerAddress&& other) {
+    address_ = other.address_;
+    args_ = other.args_;
+    other.args_ = nullptr;
+    return *this;
+  }
+
+  bool operator==(const ServerAddress& other) const { return Cmp(other) == 0; }
+
+  int Cmp(const ServerAddress& other) const;
+
+  const grpc_resolved_address& address() const { return address_; }
+  const grpc_channel_args* args() const { return args_; }
+
+  bool IsBalancer() const;
+
+ private:
+  grpc_resolved_address address_;
+  grpc_channel_args* args_;
+};
+
+//
+// ServerAddressList
+//
+
+typedef InlinedVector<ServerAddress, 1> ServerAddressList;
+
+// Returns a channel arg containing \a addresses.
+grpc_arg CreateServerAddressListChannelArg(const ServerAddressList* addresses);
+
+// Returns the ServerListAddress instance in channel_args or NULL.
+ServerAddressList* FindServerAddressListChannelArg(
+    const grpc_channel_args* channel_args);
+
+}  // namespace grpc_core
+
+#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SERVER_ADDRESS_H */

src/core/ext/filters/client_channel/subchannel.cc

@@ -837,7 +837,7 @@ static bool publish_transport_locked(grpc_subchannel* c) {
 
   /* publish */
   c->connected_subchannel.reset(grpc_core::New<grpc_core::ConnectedSubchannel>(
-      stk, c->channelz_subchannel, socket_uuid));
+      stk, c->args, c->channelz_subchannel, socket_uuid));
   gpr_log(GPR_INFO, "New connected subchannel at %p for subchannel %p",
           c->connected_subchannel.get(), c);
 
@@ -1068,16 +1068,18 @@ grpc_arg grpc_create_subchannel_address_arg(const grpc_resolved_address* addr) {
 namespace grpc_core {
 
 ConnectedSubchannel::ConnectedSubchannel(
-    grpc_channel_stack* channel_stack,
+    grpc_channel_stack* channel_stack, const grpc_channel_args* args,
     grpc_core::RefCountedPtr<grpc_core::channelz::SubchannelNode>
         channelz_subchannel,
     intptr_t socket_uuid)
     : RefCounted<ConnectedSubchannel>(&grpc_trace_stream_refcount),
       channel_stack_(channel_stack),
+      args_(grpc_channel_args_copy(args)),
       channelz_subchannel_(std::move(channelz_subchannel)),
       socket_uuid_(socket_uuid) {}
 
 ConnectedSubchannel::~ConnectedSubchannel() {
+  grpc_channel_args_destroy(args_);
   GRPC_CHANNEL_STACK_UNREF(channel_stack_, "connected_subchannel_dtor");
 }
 

src/core/ext/filters/client_channel/subchannel.h

@@ -85,28 +85,31 @@ class ConnectedSubchannel : public RefCounted<ConnectedSubchannel> {
     size_t parent_data_size;
   };
 
-  explicit ConnectedSubchannel(
-      grpc_channel_stack* channel_stack,
+  ConnectedSubchannel(
+      grpc_channel_stack* channel_stack, const grpc_channel_args* args,
       grpc_core::RefCountedPtr<grpc_core::channelz::SubchannelNode>
           channelz_subchannel,
       intptr_t socket_uuid);
   ~ConnectedSubchannel();
 
-  grpc_channel_stack* channel_stack() { return channel_stack_; }
   void NotifyOnStateChange(grpc_pollset_set* interested_parties,
                            grpc_connectivity_state* state,
                            grpc_closure* closure);
   void Ping(grpc_closure* on_initiate, grpc_closure* on_ack);
   grpc_error* CreateCall(const CallArgs& args, grpc_subchannel_call** call);
-  channelz::SubchannelNode* channelz_subchannel() {
+
+  grpc_channel_stack* channel_stack() const { return channel_stack_; }
+  const grpc_channel_args* args() const { return args_; }
+  channelz::SubchannelNode* channelz_subchannel() const {
     return channelz_subchannel_.get();
   }
-  intptr_t socket_uuid() { return socket_uuid_; }
+  intptr_t socket_uuid() const { return socket_uuid_; }
 
   size_t GetInitialCallSizeEstimate(size_t parent_data_size) const;
 
  private:
   grpc_channel_stack* channel_stack_;
+  grpc_channel_args* args_;
   // ref counted pointer to the channelz node in this connected subchannel's
   // owning subchannel.
   grpc_core::RefCountedPtr<grpc_core::channelz::SubchannelNode>

src/core/lib/iomgr/sockaddr_utils.cc

@@ -217,6 +217,7 @@ void grpc_string_to_sockaddr(grpc_resolved_address* out, char* addr, int port) {
 }
 
 char* grpc_sockaddr_to_uri(const grpc_resolved_address* resolved_addr) {
+  if (resolved_addr->len == 0) return nullptr;
   grpc_resolved_address addr_normalized;
   if (grpc_sockaddr_is_v4mapped(resolved_addr, &addr_normalized)) {
     resolved_addr = &addr_normalized;

src/python/grpcio/grpc_core_dependencies.py

@@ -322,7 +322,6 @@ CORE_SOURCE_FILES = [
     'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
     'src/core/ext/filters/client_channel/http_proxy.cc',
     'src/core/ext/filters/client_channel/lb_policy.cc',
-    'src/core/ext/filters/client_channel/lb_policy_factory.cc',
     'src/core/ext/filters/client_channel/lb_policy_registry.cc',
     'src/core/ext/filters/client_channel/parse_address.cc',
     'src/core/ext/filters/client_channel/proxy_mapper.cc',
@@ -331,6 +330,7 @@ CORE_SOURCE_FILES = [
     'src/core/ext/filters/client_channel/resolver_registry.cc',
     'src/core/ext/filters/client_channel/resolver_result_parsing.cc',
     'src/core/ext/filters/client_channel/retry_throttle.cc',
+    'src/core/ext/filters/client_channel/server_address.cc',
     'src/core/ext/filters/client_channel/subchannel.cc',
     'src/core/ext/filters/client_channel/subchannel_index.cc',
     'src/core/ext/filters/deadline/deadline_filter.cc',

test/core/client_channel/resolvers/dns_resolver_connectivity_test.cc

@@ -21,10 +21,10 @@
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/ext/filters/client_channel/resolver.h"
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/resolve_address.h"
@@ -63,8 +63,9 @@ static grpc_address_resolver_vtable test_resolver = {my_resolve_address,
 static grpc_ares_request* my_dns_lookup_ares_locked(
     const char* dns_server, const char* addr, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** lb_addrs, bool check_grpclb, char** service_config_json,
-    int query_timeout_ms, grpc_combiner* combiner) {
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
+    grpc_combiner* combiner) {
   gpr_mu_lock(&g_mu);
   GPR_ASSERT(0 == strcmp("test", addr));
   grpc_error* error = GRPC_ERROR_NONE;
@@ -74,9 +75,8 @@ static grpc_ares_request* my_dns_lookup_ares_locked(
     error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Forced Failure");
   } else {
     gpr_mu_unlock(&g_mu);
-    *lb_addrs = grpc_lb_addresses_create(1, nullptr);
-    grpc_lb_addresses_set_address(*lb_addrs, 0, nullptr, 0, false, nullptr,
-                                  nullptr);
+    *addresses = grpc_core::MakeUnique<grpc_core::ServerAddressList>();
+    (*addresses)->emplace_back(nullptr, 0, nullptr);
   }
   GRPC_CLOSURE_SCHED(on_done, error);
   return nullptr;

test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc

@@ -22,6 +22,7 @@
 
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gprpp/memory.h"
 #include "src/core/lib/iomgr/combiner.h"
@@ -40,8 +41,9 @@ static grpc_combiner* g_combiner;
 static grpc_ares_request* (*g_default_dns_lookup_ares_locked)(
     const char* dns_server, const char* name, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** addrs, bool check_grpclb, char** service_config_json,
-    int query_timeout_ms, grpc_combiner* combiner);
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
+    grpc_combiner* combiner);
 
 // Counter incremented by test_resolve_address_impl indicating the number of
 // times a system-level resolution has happened.
@@ -90,11 +92,12 @@ static grpc_address_resolver_vtable test_resolver = {
 static grpc_ares_request* test_dns_lookup_ares_locked(
     const char* dns_server, const char* name, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** addrs, bool check_grpclb, char** service_config_json,
-    int query_timeout_ms, grpc_combiner* combiner) {
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
+    grpc_combiner* combiner) {
   grpc_ares_request* result = g_default_dns_lookup_ares_locked(
-      dns_server, name, default_port, g_iomgr_args.pollset_set, on_done, addrs,
-      check_grpclb, service_config_json, query_timeout_ms, combiner);
+      dns_server, name, default_port, g_iomgr_args.pollset_set, on_done,
+      addresses, check_grpclb, service_config_json, query_timeout_ms, combiner);
   ++g_resolution_count;
   static grpc_millis last_resolution_time = 0;
   if (last_resolution_time == 0) {

test/core/client_channel/resolvers/fake_resolver_test.cc

@@ -22,10 +22,10 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gprpp/ref_counted_ptr.h"
 #include "src/core/lib/iomgr/combiner.h"
@@ -63,12 +63,14 @@ void on_resolution_cb(void* arg, grpc_error* error) {
   // We only check the addresses channel arg because that's the only one
   // explicitly set by the test via
   // FakeResolverResponseGenerator::SetResponse().
-  const grpc_lb_addresses* actual_lb_addresses =
-      grpc_lb_addresses_find_channel_arg(res->resolver_result);
-  const grpc_lb_addresses* expected_lb_addresses =
-      grpc_lb_addresses_find_channel_arg(res->expected_resolver_result);
-  GPR_ASSERT(
-      grpc_lb_addresses_cmp(actual_lb_addresses, expected_lb_addresses) == 0);
+  const grpc_core::ServerAddressList* actual_addresses =
+      grpc_core::FindServerAddressListChannelArg(res->resolver_result);
+  const grpc_core::ServerAddressList* expected_addresses =
+      grpc_core::FindServerAddressListChannelArg(res->expected_resolver_result);
+  GPR_ASSERT(actual_addresses->size() == expected_addresses->size());
+  for (size_t i = 0; i < expected_addresses->size(); ++i) {
+    GPR_ASSERT((*actual_addresses)[i] == (*expected_addresses)[i]);
+  }
   grpc_channel_args_destroy(res->resolver_result);
   grpc_channel_args_destroy(res->expected_resolver_result);
   gpr_event_set(&res->ev, (void*)1);
@@ -80,27 +82,35 @@ static grpc_channel_args* create_new_resolver_result() {
   const size_t num_addresses = 2;
   char* uri_string;
   char* balancer_name;
-  // Create grpc_lb_addresses.
-  grpc_lb_addresses* addresses =
-      grpc_lb_addresses_create(num_addresses, nullptr);
+  // Create address list.
+  grpc_core::ServerAddressList addresses;
   for (size_t i = 0; i < num_addresses; ++i) {
     gpr_asprintf(&uri_string, "ipv4:127.0.0.1:100%" PRIuPTR,
                  test_counter * num_addresses + i);
     grpc_uri* uri = grpc_uri_parse(uri_string, true);
     gpr_asprintf(&balancer_name, "balancer%" PRIuPTR,
                  test_counter * num_addresses + i);
-    grpc_lb_addresses_set_address_from_uri(
-        addresses, i, uri, bool(num_addresses % 2), balancer_name, nullptr);
+    grpc_resolved_address address;
+    GPR_ASSERT(grpc_parse_uri(uri, &address));
+    grpc_core::InlinedVector<grpc_arg, 2> args_to_add;
+    const bool is_balancer = num_addresses % 2;
+    if (is_balancer) {
+      args_to_add.emplace_back(grpc_channel_arg_integer_create(
+          const_cast<char*>(GRPC_ARG_ADDRESS_IS_BALANCER), 1));
+      args_to_add.emplace_back(grpc_channel_arg_string_create(
+          const_cast<char*>(GRPC_ARG_ADDRESS_BALANCER_NAME), balancer_name));
+    }
+    grpc_channel_args* args = grpc_channel_args_copy_and_add(
+        nullptr, args_to_add.data(), args_to_add.size());
+    addresses.emplace_back(address.addr, address.len, args);
     gpr_free(balancer_name);
     grpc_uri_destroy(uri);
     gpr_free(uri_string);
   }
-  // Convert grpc_lb_addresses to grpc_channel_args.
-  const grpc_arg addresses_arg =
-      grpc_lb_addresses_create_channel_arg(addresses);
+  // Embed the address list in channel args.
+  const grpc_arg addresses_arg = CreateServerAddressListChannelArg(&addresses);
   grpc_channel_args* results =
       grpc_channel_args_copy_and_add(nullptr, &addresses_arg, 1);
-  grpc_lb_addresses_destroy(addresses);
   ++test_counter;
   return results;
 }

test/core/end2end/fuzzers/api_fuzzer.cc

@@ -24,8 +24,8 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/env.h"
@@ -325,7 +325,7 @@ typedef struct addr_req {
   char* addr;
   grpc_closure* on_done;
   grpc_resolved_addresses** addrs;
-  grpc_lb_addresses** lb_addrs;
+  grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses;
 } addr_req;
 
 static void finish_resolve(void* arg, grpc_error* error) {
@@ -340,11 +340,9 @@ static void finish_resolve(void* arg, grpc_error* error) {
           gpr_malloc(sizeof(*addrs->addrs)));
       addrs->addrs[0].len = 0;
       *r->addrs = addrs;
-    } else if (r->lb_addrs != nullptr) {
-      grpc_lb_addresses* lb_addrs = grpc_lb_addresses_create(1, nullptr);
-      grpc_lb_addresses_set_address(lb_addrs, 0, nullptr, 0, false, nullptr,
-                                    nullptr);
-      *r->lb_addrs = lb_addrs;
+    } else if (r->addresses != nullptr) {
+      *r->addresses = grpc_core::MakeUnique<grpc_core::ServerAddressList>();
+      (*r->addresses)->emplace_back(nullptr, 0, nullptr);
     }
     GRPC_CLOSURE_SCHED(r->on_done, GRPC_ERROR_NONE);
   } else {
@@ -354,18 +352,17 @@ static void finish_resolve(void* arg, grpc_error* error) {
   }
 
   gpr_free(r->addr);
-  gpr_free(r);
+  grpc_core::Delete(r);
 }
 
 void my_resolve_address(const char* addr, const char* default_port,
                         grpc_pollset_set* interested_parties,
                         grpc_closure* on_done,
-                        grpc_resolved_addresses** addresses) {
-  addr_req* r = static_cast<addr_req*>(gpr_malloc(sizeof(*r)));
+                        grpc_resolved_addresses** addrs) {
+  addr_req* r = grpc_core::New<addr_req>();
   r->addr = gpr_strdup(addr);
   r->on_done = on_done;
-  r->addrs = addresses;
-  r->lb_addrs = nullptr;
+  r->addrs = addrs;
   grpc_timer_init(
       &r->timer, GPR_MS_PER_SEC + grpc_core::ExecCtx::Get()->Now(),
       GRPC_CLOSURE_CREATE(finish_resolve, r, grpc_schedule_on_exec_ctx));
@@ -377,13 +374,14 @@ static grpc_address_resolver_vtable fuzzer_resolver = {my_resolve_address,
 grpc_ares_request* my_dns_lookup_ares_locked(
     const char* dns_server, const char* addr, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** lb_addrs, bool check_grpclb, char** service_config_json,
-    int query_timeout, grpc_combiner* combiner) {
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses,
+    bool check_grpclb, char** service_config_json, int query_timeout,
+    grpc_combiner* combiner) {
   addr_req* r = static_cast<addr_req*>(gpr_malloc(sizeof(*r)));
   r->addr = gpr_strdup(addr);
   r->on_done = on_done;
   r->addrs = nullptr;
-  r->lb_addrs = lb_addrs;
+  r->addresses = addresses;
   grpc_timer_init(
       &r->timer, GPR_MS_PER_SEC + grpc_core::ExecCtx::Get()->Now(),
       GRPC_CLOSURE_CREATE(finish_resolve, r, grpc_schedule_on_exec_ctx));

test/core/end2end/goaway_server_test.cc

@@ -28,8 +28,8 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 #include <string.h>
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/sockaddr.h"
 #include "test/core/end2end/cq_verifier.h"
@@ -47,8 +47,9 @@ static int g_resolve_port = -1;
 static grpc_ares_request* (*iomgr_dns_lookup_ares_locked)(
     const char* dns_server, const char* addr, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** addresses, bool check_grpclb,
-    char** service_config_json, int query_timeout_ms, grpc_combiner* combiner);
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
+    grpc_combiner* combiner);
 
 static void (*iomgr_cancel_ares_request_locked)(grpc_ares_request* request);
 
@@ -103,11 +104,12 @@ static grpc_address_resolver_vtable test_resolver = {
 static grpc_ares_request* my_dns_lookup_ares_locked(
     const char* dns_server, const char* addr, const char* default_port,
     grpc_pollset_set* interested_parties, grpc_closure* on_done,
-    grpc_lb_addresses** lb_addrs, bool check_grpclb, char** service_config_json,
-    int query_timeout_ms, grpc_combiner* combiner) {
+    grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses,
+    bool check_grpclb, char** service_config_json, int query_timeout_ms,
+    grpc_combiner* combiner) {
   if (0 != strcmp(addr, "test")) {
     return iomgr_dns_lookup_ares_locked(
-        dns_server, addr, default_port, interested_parties, on_done, lb_addrs,
+        dns_server, addr, default_port, interested_parties, on_done, addresses,
         check_grpclb, service_config_json, query_timeout_ms, combiner);
   }
 
@@ -117,15 +119,12 @@ static grpc_ares_request* my_dns_lookup_ares_locked(
     gpr_mu_unlock(&g_mu);
     error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Forced Failure");
   } else {
-    *lb_addrs = grpc_lb_addresses_create(1, nullptr);
-    grpc_sockaddr_in* sa =
-        static_cast<grpc_sockaddr_in*>(gpr_zalloc(sizeof(grpc_sockaddr_in)));
-    sa->sin_family = GRPC_AF_INET;
-    sa->sin_addr.s_addr = 0x100007f;
-    sa->sin_port = grpc_htons(static_cast<uint16_t>(g_resolve_port));
-    grpc_lb_addresses_set_address(*lb_addrs, 0, sa, sizeof(*sa), false, nullptr,
-                                  nullptr);
-    gpr_free(sa);
+    *addresses = grpc_core::MakeUnique<grpc_core::ServerAddressList>();
+    grpc_sockaddr_in sa;
+    sa.sin_family = GRPC_AF_INET;
+    sa.sin_addr.s_addr = 0x100007f;
+    sa.sin_port = grpc_htons(static_cast<uint16_t>(g_resolve_port));
+    (*addresses)->emplace_back(&sa, sizeof(sa), nullptr);
     gpr_mu_unlock(&g_mu);
   }
   GRPC_CLOSURE_SCHED(on_done, error);

test/core/end2end/no_server_test.cc

@@ -23,6 +23,7 @@
 #include <grpc/support/log.h>
 
 #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
 #include "test/core/end2end/cq_verifier.h"
 #include "test/core/util/test_config.h"
 

test/core/util/ubsan_suppressions.txt

@@ -25,7 +25,6 @@ alignment:absl::little_endian::Store64
 alignment:absl::little_endian::Load64
 float-divide-by-zero:grpc::testing::postprocess_scenario_result
 enum:grpc_op_string
-nonnull-attribute:grpc_lb_addresses_copy
 signed-integer-overflow:chrono
 enum:grpc_http2_error_to_grpc_status
-enum:grpc_chttp2_cancel_stream
+enum:grpc_chttp2_cancel_stream

test/cpp/client/client_channel_stress_test.cc

@@ -34,7 +34,9 @@
 #include <grpcpp/server.h>
 #include <grpcpp/server_builder.h>
 
+#include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/gprpp/ref_counted_ptr.h"
 #include "src/core/lib/gprpp/thd.h"
 #include "src/core/lib/iomgr/sockaddr.h"
@@ -216,23 +218,31 @@ class ClientChannelStressTest {
 
   void SetNextResolution(const std::vector<AddressData>& address_data) {
     grpc_core::ExecCtx exec_ctx;
-    grpc_lb_addresses* addresses =
-        grpc_lb_addresses_create(address_data.size(), nullptr);
-    for (size_t i = 0; i < address_data.size(); ++i) {
+    grpc_core::ServerAddressList addresses;
+    for (const auto& addr : address_data) {
       char* lb_uri_str;
-      gpr_asprintf(&lb_uri_str, "ipv4:127.0.0.1:%d", address_data[i].port);
+      gpr_asprintf(&lb_uri_str, "ipv4:127.0.0.1:%d", addr.port);
       grpc_uri* lb_uri = grpc_uri_parse(lb_uri_str, true);
       GPR_ASSERT(lb_uri != nullptr);
-      grpc_lb_addresses_set_address_from_uri(
-          addresses, i, lb_uri, address_data[i].is_balancer,
-          address_data[i].balancer_name.c_str(), nullptr);
+      grpc_resolved_address address;
+      GPR_ASSERT(grpc_parse_uri(lb_uri, &address));
+      std::vector<grpc_arg> args_to_add;
+      if (addr.is_balancer) {
+        args_to_add.emplace_back(grpc_channel_arg_integer_create(
+            const_cast<char*>(GRPC_ARG_ADDRESS_IS_BALANCER), 1));
+        args_to_add.emplace_back(grpc_channel_arg_string_create(
+            const_cast<char*>(GRPC_ARG_ADDRESS_BALANCER_NAME),
+            const_cast<char*>(addr.balancer_name.c_str())));
+      }
+      grpc_channel_args* args = grpc_channel_args_copy_and_add(
+          nullptr, args_to_add.data(), args_to_add.size());
+      addresses.emplace_back(address.addr, address.len, args);
       grpc_uri_destroy(lb_uri);
       gpr_free(lb_uri_str);
     }
-    grpc_arg fake_addresses = grpc_lb_addresses_create_channel_arg(addresses);
+    grpc_arg fake_addresses = CreateServerAddressListChannelArg(&addresses);
     grpc_channel_args fake_result = {1, &fake_addresses};
     response_generator_->SetResponse(&fake_result);
-    grpc_lb_addresses_destroy(addresses);
   }
 
   void KeepSendingRequests() {

test/cpp/end2end/client_lb_end2end_test.cc

@@ -35,7 +35,9 @@
 #include <grpcpp/server.h>
 #include <grpcpp/server_builder.h>
 
+#include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/ext/filters/client_channel/subchannel_index.h"
 #include "src/core/lib/backoff/backoff.h"
 #include "src/core/lib/gpr/env.h"
@@ -159,24 +161,22 @@ class ClientLbEnd2endTest : public ::testing::Test {
   }
 
   grpc_channel_args* BuildFakeResults(const std::vector<int>& ports) {
-    grpc_lb_addresses* addresses =
-        grpc_lb_addresses_create(ports.size(), nullptr);
-    for (size_t i = 0; i < ports.size(); ++i) {
+    grpc_core::ServerAddressList addresses;
+    for (const int& port : ports) {
       char* lb_uri_str;
-      gpr_asprintf(&lb_uri_str, "ipv4:127.0.0.1:%d", ports[i]);
+      gpr_asprintf(&lb_uri_str, "ipv4:127.0.0.1:%d", port);
       grpc_uri* lb_uri = grpc_uri_parse(lb_uri_str, true);
       GPR_ASSERT(lb_uri != nullptr);
-      grpc_lb_addresses_set_address_from_uri(addresses, i, lb_uri,
-                                             false /* is balancer */,
-                                             "" /* balancer name */, nullptr);
+      grpc_resolved_address address;
+      GPR_ASSERT(grpc_parse_uri(lb_uri, &address));
+      addresses.emplace_back(address.addr, address.len, nullptr /* args */);
       grpc_uri_destroy(lb_uri);
       gpr_free(lb_uri_str);
     }
     const grpc_arg fake_addresses =
-        grpc_lb_addresses_create_channel_arg(addresses);
+        CreateServerAddressListChannelArg(&addresses);
     grpc_channel_args* fake_results =
         grpc_channel_args_copy_and_add(nullptr, &fake_addresses, 1);
-    grpc_lb_addresses_destroy(addresses);
     return fake_results;
   }
 

test/cpp/end2end/grpclb_end2end_test.cc

@@ -32,7 +32,9 @@
 #include <grpcpp/server.h>
 #include <grpcpp/server_builder.h>
 
+#include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/gpr/env.h"
 #include "src/core/lib/gprpp/ref_counted_ptr.h"
 #include "src/core/lib/iomgr/sockaddr.h"
@@ -486,18 +488,27 @@ class GrpclbEnd2endTest : public ::testing::Test {
     grpc::string balancer_name;
   };
 
-  grpc_lb_addresses* CreateLbAddressesFromAddressDataList(
+  grpc_core::ServerAddressList CreateLbAddressesFromAddressDataList(
       const std::vector<AddressData>& address_data) {
-    grpc_lb_addresses* addresses =
-        grpc_lb_addresses_create(address_data.size(), nullptr);
-    for (size_t i = 0; i < address_data.size(); ++i) {
+    grpc_core::ServerAddressList addresses;
+    for (const auto& addr : address_data) {
       char* lb_uri_str;
-      gpr_asprintf(&lb_uri_str, "ipv4:127.0.0.1:%d", address_data[i].port);
+      gpr_asprintf(&lb_uri_str, "ipv4:127.0.0.1:%d", addr.port);
       grpc_uri* lb_uri = grpc_uri_parse(lb_uri_str, true);
       GPR_ASSERT(lb_uri != nullptr);
-      grpc_lb_addresses_set_address_from_uri(
-          addresses, i, lb_uri, address_data[i].is_balancer,
-          address_data[i].balancer_name.c_str(), nullptr);
+      grpc_resolved_address address;
+      GPR_ASSERT(grpc_parse_uri(lb_uri, &address));
+      std::vector<grpc_arg> args_to_add;
+      if (addr.is_balancer) {
+        args_to_add.emplace_back(grpc_channel_arg_integer_create(
+            const_cast<char*>(GRPC_ARG_ADDRESS_IS_BALANCER), 1));
+        args_to_add.emplace_back(grpc_channel_arg_string_create(
+            const_cast<char*>(GRPC_ARG_ADDRESS_BALANCER_NAME),
+            const_cast<char*>(addr.balancer_name.c_str())));
+      }
+      grpc_channel_args* args = grpc_channel_args_copy_and_add(
+          nullptr, args_to_add.data(), args_to_add.size());
+      addresses.emplace_back(address.addr, address.len, args);
       grpc_uri_destroy(lb_uri);
       gpr_free(lb_uri_str);
     }
@@ -506,23 +517,21 @@ class GrpclbEnd2endTest : public ::testing::Test {
 
   void SetNextResolution(const std::vector<AddressData>& address_data) {
     grpc_core::ExecCtx exec_ctx;
-    grpc_lb_addresses* addresses =
+    grpc_core::ServerAddressList addresses =
         CreateLbAddressesFromAddressDataList(address_data);
-    grpc_arg fake_addresses = grpc_lb_addresses_create_channel_arg(addresses);
+    grpc_arg fake_addresses = CreateServerAddressListChannelArg(&addresses);
     grpc_channel_args fake_result = {1, &fake_addresses};
     response_generator_->SetResponse(&fake_result);
-    grpc_lb_addresses_destroy(addresses);
   }
 
   void SetNextReresolutionResponse(
       const std::vector<AddressData>& address_data) {
     grpc_core::ExecCtx exec_ctx;
-    grpc_lb_addresses* addresses =
+    grpc_core::ServerAddressList addresses =
         CreateLbAddressesFromAddressDataList(address_data);
-    grpc_arg fake_addresses = grpc_lb_addresses_create_channel_arg(addresses);
+    grpc_arg fake_addresses = CreateServerAddressListChannelArg(&addresses);
     grpc_channel_args fake_result = {1, &fake_addresses};
     response_generator_->SetReresolutionResponse(&fake_result);
-    grpc_lb_addresses_destroy(addresses);
   }
 
   const std::vector<int> GetBackendPorts(const size_t start_index = 0) const {

test/cpp/naming/address_sorting_test.cc

@@ -37,6 +37,7 @@
 #include "src/core/ext/filters/client_channel/resolver.h"
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/env.h"
 #include "src/core/lib/gpr/host_port.h"
@@ -167,30 +168,26 @@ void OverrideAddressSortingSourceAddrFactory(
   address_sorting_override_source_addr_factory_for_testing(factory);
 }
 
-grpc_lb_addresses* BuildLbAddrInputs(std::vector<TestAddress> test_addrs) {
-  grpc_lb_addresses* lb_addrs = grpc_lb_addresses_create(0, nullptr);
-  lb_addrs->addresses =
-      (grpc_lb_address*)gpr_zalloc(sizeof(grpc_lb_address) * test_addrs.size());
-  lb_addrs->num_addresses = test_addrs.size();
-  for (size_t i = 0; i < test_addrs.size(); i++) {
-    lb_addrs->addresses[i].address =
-        TestAddressToGrpcResolvedAddress(test_addrs[i]);
+grpc_core::ServerAddressList BuildLbAddrInputs(
+    const std::vector<TestAddress>& test_addrs) {
+  grpc_core::ServerAddressList addresses;
+  for (const auto& addr : test_addrs) {
+    addresses.emplace_back(TestAddressToGrpcResolvedAddress(addr), nullptr);
   }
-  return lb_addrs;
+  return addresses;
 }
 
-void VerifyLbAddrOutputs(grpc_lb_addresses* lb_addrs,
+void VerifyLbAddrOutputs(const grpc_core::ServerAddressList addresses,
                          std::vector<std::string> expected_addrs) {
-  EXPECT_EQ(lb_addrs->num_addresses, expected_addrs.size());
-  for (size_t i = 0; i < lb_addrs->num_addresses; i++) {
+  EXPECT_EQ(addresses.size(), expected_addrs.size());
+  for (size_t i = 0; i < addresses.size(); ++i) {
     char* ip_addr_str;
-    grpc_sockaddr_to_string(&ip_addr_str, &lb_addrs->addresses[i].address,
+    grpc_sockaddr_to_string(&ip_addr_str, &addresses[i].address(),
                             false /* normalize */);
     EXPECT_EQ(expected_addrs[i], ip_addr_str);
     gpr_free(ip_addr_str);
   }
   grpc_core::ExecCtx exec_ctx;
-  grpc_lb_addresses_destroy(lb_addrs);
 }
 
 /* We need to run each test case inside of its own
@@ -212,11 +209,11 @@ TEST_F(AddressSortingTest, TestDepriotizesUnreachableAddresses) {
       {
           {"1.2.3.4:443", {"4.3.2.1:443", AF_INET}},
       });
-  auto* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"1.2.3.4:443", AF_INET},
       {"5.6.7.8:443", AF_INET},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "1.2.3.4:443",
                                     "5.6.7.8:443",
@@ -235,7 +232,7 @@ TEST_F(AddressSortingTest, TestDepriotizesUnsupportedDomainIpv6) {
       {"[2607:f8b0:400a:801::1002]:443", AF_INET6},
       {"1.2.3.4:443", AF_INET},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "1.2.3.4:443",
                                     "[2607:f8b0:400a:801::1002]:443",
@@ -251,11 +248,11 @@ TEST_F(AddressSortingTest, TestDepriotizesUnsupportedDomainIpv4) {
           {"1.2.3.4:443", {"4.3.2.1:0", AF_INET}},
           {"[2607:f8b0:400a:801::1002]:443", {"[fec0::1234]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[2607:f8b0:400a:801::1002]:443", AF_INET6},
       {"1.2.3.4:443", AF_INET},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[2607:f8b0:400a:801::1002]:443",
                                     "1.2.3.4:443",
@@ -275,11 +272,11 @@ TEST_F(AddressSortingTest, TestDepriotizesNonMatchingScope) {
           {"[fec0::5000]:443",
            {"[fec0::5001]:0", AF_INET6}},  // site-local and site-local scope
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[2000:f8b0:400a:801::1002]:443", AF_INET6},
       {"[fec0::5000]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[fec0::5000]:443",
                                     "[2000:f8b0:400a:801::1002]:443",
@@ -298,11 +295,11 @@ TEST_F(AddressSortingTest, TestUsesLabelFromDefaultTable) {
           {"[2001::5001]:443",
            {"[2001::5002]:0", AF_INET6}},  // matching labels
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[2002::5001]:443", AF_INET6},
       {"[2001::5001]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[2001::5001]:443",
                                     "[2002::5001]:443",
@@ -321,11 +318,11 @@ TEST_F(AddressSortingTest, TestUsesLabelFromDefaultTableInputFlipped) {
           {"[2001::5001]:443",
            {"[2001::5002]:0", AF_INET6}},  // matching labels
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[2001::5001]:443", AF_INET6},
       {"[2002::5001]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[2001::5001]:443",
                                     "[2002::5001]:443",
@@ -344,11 +341,11 @@ TEST_F(AddressSortingTest,
           {"[3ffe::5001]:443", {"[3ffe::5002]:0", AF_INET6}},
           {"1.2.3.4:443", {"5.6.7.8:0", AF_INET}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe::5001]:443", AF_INET6},
       {"1.2.3.4:443", AF_INET},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(
       lb_addrs, {
                     // The AF_INET address should be IPv4-mapped by the sort,
@@ -377,11 +374,11 @@ TEST_F(AddressSortingTest,
           {"[::1]:443", {"[::1]:0", AF_INET6}},
           {v4_compat_dest, {v4_compat_src, AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {v4_compat_dest, AF_INET6},
       {"[::1]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[::1]:443",
                                     v4_compat_dest,
@@ -400,11 +397,11 @@ TEST_F(AddressSortingTest,
           {"[1234::2]:443", {"[1234::2]:0", AF_INET6}},
           {"[::1]:443", {"[::1]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[1234::2]:443", AF_INET6},
       {"[::1]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(
       lb_addrs,
       {
@@ -424,11 +421,11 @@ TEST_F(AddressSortingTest,
           {"[2001::1234]:443", {"[2001::5678]:0", AF_INET6}},
           {"[2000::5001]:443", {"[2000::5002]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[2001::1234]:443", AF_INET6},
       {"[2000::5001]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(
       lb_addrs, {
                     // The 2000::/16 address should match the ::/0 prefix rule
@@ -448,11 +445,11 @@ TEST_F(
           {"[2001::1231]:443", {"[2001::1232]:0", AF_INET6}},
           {"[2000::5001]:443", {"[2000::5002]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[2001::1231]:443", AF_INET6},
       {"[2000::5001]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[2000::5001]:443",
                                     "[2001::1231]:443",
@@ -469,11 +466,11 @@ TEST_F(AddressSortingTest,
           {"[fec0::1234]:443", {"[fec0::5678]:0", AF_INET6}},
           {"[fc00::5001]:443", {"[fc00::5002]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[fec0::1234]:443", AF_INET6},
       {"[fc00::5001]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[fc00::5001]:443",
                                     "[fec0::1234]:443",
@@ -494,11 +491,11 @@ TEST_F(
           {"[::ffff:1.1.1.2]:443", {"[::ffff:1.1.1.3]:0", AF_INET6}},
           {"[1234::2]:443", {"[1234::3]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[::ffff:1.1.1.2]:443", AF_INET6},
       {"[1234::2]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     // ::ffff:0:2 should match the v4-mapped
                                     // precedence entry and be deprioritized.
@@ -521,11 +518,11 @@ TEST_F(AddressSortingTest, TestPrefersSmallerScope) {
           {"[fec0::1234]:443", {"[fec0::5678]:0", AF_INET6}},
           {"[3ffe::5001]:443", {"[3ffe::5002]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe::5001]:443", AF_INET6},
       {"[fec0::1234]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[fec0::1234]:443",
                                     "[3ffe::5001]:443",
@@ -546,11 +543,11 @@ TEST_F(AddressSortingTest, TestPrefersLongestMatchingSrcDstPrefix) {
           {"[3ffe:1234::]:443", {"[3ffe:1235::]:0", AF_INET6}},
           {"[3ffe:5001::]:443", {"[3ffe:4321::]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe:5001::]:443", AF_INET6},
       {"[3ffe:1234::]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[3ffe:1234::]:443",
                                     "[3ffe:5001::]:443",
@@ -567,11 +564,11 @@ TEST_F(AddressSortingTest,
           {"[3ffe::1234]:443", {"[3ffe::1235]:0", AF_INET6}},
           {"[3ffe::5001]:443", {"[3ffe::4321]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe::5001]:443", AF_INET6},
       {"[3ffe::1234]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[3ffe::1234]:443",
                                     "[3ffe::5001]:443",
@@ -587,11 +584,11 @@ TEST_F(AddressSortingTest, TestPrefersLongestPrefixStressInnerBytePrefix) {
           {"[3ffe:8000::]:443", {"[3ffe:C000::]:0", AF_INET6}},
           {"[3ffe:2000::]:443", {"[3ffe:3000::]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe:8000::]:443", AF_INET6},
       {"[3ffe:2000::]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[3ffe:2000::]:443",
                                     "[3ffe:8000::]:443",
@@ -607,11 +604,11 @@ TEST_F(AddressSortingTest, TestPrefersLongestPrefixDiffersOnHighestBitOfByte) {
           {"[3ffe:6::]:443", {"[3ffe:8::]:0", AF_INET6}},
           {"[3ffe:c::]:443", {"[3ffe:8::]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe:6::]:443", AF_INET6},
       {"[3ffe:c::]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[3ffe:c::]:443",
                                     "[3ffe:6::]:443",
@@ -629,11 +626,11 @@ TEST_F(AddressSortingTest, TestPrefersLongestPrefixDiffersByLastBit) {
           {"[3ffe:1111:1111:1110::]:443",
            {"[3ffe:1111:1111:1111::]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe:1111:1111:1110::]:443", AF_INET6},
       {"[3ffe:1111:1111:1111::]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[3ffe:1111:1111:1111::]:443",
                                     "[3ffe:1111:1111:1110::]:443",
@@ -651,11 +648,11 @@ TEST_F(AddressSortingTest, TestStableSort) {
           {"[3ffe::1234]:443", {"[3ffe::1236]:0", AF_INET6}},
           {"[3ffe::1235]:443", {"[3ffe::1237]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe::1234]:443", AF_INET6},
       {"[3ffe::1235]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[3ffe::1234]:443",
                                     "[3ffe::1235]:443",
@@ -674,14 +671,14 @@ TEST_F(AddressSortingTest, TestStableSortFiveElements) {
           {"[3ffe::1234]:443", {"[3ffe::1204]:0", AF_INET6}},
           {"[3ffe::1235]:443", {"[3ffe::1205]:0", AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe::1231]:443", AF_INET6},
       {"[3ffe::1232]:443", AF_INET6},
       {"[3ffe::1233]:443", AF_INET6},
       {"[3ffe::1234]:443", AF_INET6},
       {"[3ffe::1235]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[3ffe::1231]:443",
                                     "[3ffe::1232]:443",
@@ -695,14 +692,14 @@ TEST_F(AddressSortingTest, TestStableSortNoSrcAddrsExist) {
   bool ipv4_supported = true;
   bool ipv6_supported = true;
   OverrideAddressSortingSourceAddrFactory(ipv4_supported, ipv6_supported, {});
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[3ffe::1231]:443", AF_INET6},
       {"[3ffe::1232]:443", AF_INET6},
       {"[3ffe::1233]:443", AF_INET6},
       {"[3ffe::1234]:443", AF_INET6},
       {"[3ffe::1235]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[3ffe::1231]:443",
                                     "[3ffe::1232]:443",
@@ -716,11 +713,11 @@ TEST_F(AddressSortingTest, TestStableSortNoSrcAddrsExistWithIpv4) {
   bool ipv4_supported = true;
   bool ipv6_supported = true;
   OverrideAddressSortingSourceAddrFactory(ipv4_supported, ipv6_supported, {});
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[::ffff:5.6.7.8]:443", AF_INET6},
       {"1.2.3.4:443", AF_INET},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[::ffff:5.6.7.8]:443",
                                     "1.2.3.4:443",
@@ -744,11 +741,11 @@ TEST_F(AddressSortingTest, TestStableSortV4CompatAndSiteLocalAddresses) {
           {"[fec0::2000]:443", {"[fec0::2001]:0", AF_INET6}},
           {v4_compat_dest, {v4_compat_src, AF_INET6}},
       });
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[fec0::2000]:443", AF_INET6},
       {v4_compat_dest, AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs,
                       {
                           // The sort should be stable since
@@ -765,11 +762,11 @@ TEST_F(AddressSortingTest, TestStableSortV4CompatAndSiteLocalAddresses) {
  * (whether ipv4 loopback is available or not, an available ipv6
  * loopback should be preferred). */
 TEST_F(AddressSortingTest, TestPrefersIpv6Loopback) {
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"[::1]:443", AF_INET6},
       {"127.0.0.1:443", AF_INET},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[::1]:443",
                                     "127.0.0.1:443",
@@ -779,11 +776,11 @@ TEST_F(AddressSortingTest, TestPrefersIpv6Loopback) {
 /* Flip the order of the inputs above and expect the same output order
  * (try to rule out influence of arbitrary qsort ordering) */
 TEST_F(AddressSortingTest, TestPrefersIpv6LoopbackInputsFlipped) {
-  grpc_lb_addresses* lb_addrs = BuildLbAddrInputs({
+  auto lb_addrs = BuildLbAddrInputs({
       {"127.0.0.1:443", AF_INET},
       {"[::1]:443", AF_INET6},
   });
-  grpc_cares_wrapper_address_sorting_sort(lb_addrs);
+  grpc_cares_wrapper_address_sorting_sort(&lb_addrs);
   VerifyLbAddrOutputs(lb_addrs, {
                                     "[::1]:443",
                                     "127.0.0.1:443",

test/cpp/naming/resolver_component_test.cc

@@ -41,6 +41,7 @@
 #include "src/core/ext/filters/client_channel/resolver.h"
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/ext/filters/client_channel/server_address.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/env.h"
 #include "src/core/lib/gpr/host_port.h"
@@ -382,23 +383,19 @@ void CheckResolverResultLocked(void* argsp, grpc_error* err) {
   EXPECT_EQ(err, GRPC_ERROR_NONE);
   ArgsStruct* args = (ArgsStruct*)argsp;
   grpc_channel_args* channel_args = args->channel_args;
-  const grpc_arg* channel_arg =
-      grpc_channel_args_find(channel_args, GRPC_ARG_LB_ADDRESSES);
-  GPR_ASSERT(channel_arg != nullptr);
-  GPR_ASSERT(channel_arg->type == GRPC_ARG_POINTER);
-  grpc_lb_addresses* addresses =
-      (grpc_lb_addresses*)channel_arg->value.pointer.p;
+  grpc_core::ServerAddressList* addresses =
+      grpc_core::FindServerAddressListChannelArg(channel_args);
   gpr_log(GPR_INFO, "num addrs found: %" PRIdPTR ". expected %" PRIdPTR,
-          addresses->num_addresses, args->expected_addrs.size());
-  GPR_ASSERT(addresses->num_addresses == args->expected_addrs.size());
+          addresses->size(), args->expected_addrs.size());
+  GPR_ASSERT(addresses->size() == args->expected_addrs.size());
   std::vector<GrpcLBAddress> found_lb_addrs;
-  for (size_t i = 0; i < addresses->num_addresses; i++) {
-    grpc_lb_address addr = addresses->addresses[i];
+  for (size_t i = 0; i < addresses->size(); i++) {
+    grpc_core::ServerAddress& addr = (*addresses)[i];
     char* str;
-    grpc_sockaddr_to_string(&str, &addr.address, 1 /* normalize */);
+    grpc_sockaddr_to_string(&str, &addr.address(), 1 /* normalize */);
     gpr_log(GPR_INFO, "%s", str);
     found_lb_addrs.emplace_back(
-        GrpcLBAddress(std::string(str), addr.is_balancer));
+        GrpcLBAddress(std::string(str), addr.IsBalancer()));
     gpr_free(str);
   }
   if (args->expected_addrs.size() != found_lb_addrs.size()) {

tools/doxygen/Doxyfile.core.internal

@@ -923,7 +923,6 @@ src/core/ext/filters/client_channel/lb_policy/xds/xds_client_stats.cc \
 src/core/ext/filters/client_channel/lb_policy/xds/xds_client_stats.h \
 src/core/ext/filters/client_channel/lb_policy/xds/xds_load_balancer_api.cc \
 src/core/ext/filters/client_channel/lb_policy/xds/xds_load_balancer_api.h \
-src/core/ext/filters/client_channel/lb_policy_factory.cc \
 src/core/ext/filters/client_channel/lb_policy_factory.h \
 src/core/ext/filters/client_channel/lb_policy_registry.cc \
 src/core/ext/filters/client_channel/lb_policy_registry.h \
@@ -959,6 +958,8 @@ src/core/ext/filters/client_channel/resolver_result_parsing.cc \
 src/core/ext/filters/client_channel/resolver_result_parsing.h \
 src/core/ext/filters/client_channel/retry_throttle.cc \
 src/core/ext/filters/client_channel/retry_throttle.h \
+src/core/ext/filters/client_channel/server_address.cc \
+src/core/ext/filters/client_channel/server_address.h \
 src/core/ext/filters/client_channel/subchannel.cc \
 src/core/ext/filters/client_channel/subchannel.h \
 src/core/ext/filters/client_channel/subchannel_index.cc \

tools/run_tests/generated/sources_and_headers.json

@@ -10074,6 +10074,7 @@
       "src/core/ext/filters/client_channel/resolver_registry.h", 
       "src/core/ext/filters/client_channel/resolver_result_parsing.h", 
       "src/core/ext/filters/client_channel/retry_throttle.h", 
+      "src/core/ext/filters/client_channel/server_address.h", 
       "src/core/ext/filters/client_channel/subchannel.h", 
       "src/core/ext/filters/client_channel/subchannel_index.h"
     ], 
@@ -10101,7 +10102,6 @@
       "src/core/ext/filters/client_channel/http_proxy.h", 
       "src/core/ext/filters/client_channel/lb_policy.cc", 
       "src/core/ext/filters/client_channel/lb_policy.h", 
-      "src/core/ext/filters/client_channel/lb_policy_factory.cc", 
       "src/core/ext/filters/client_channel/lb_policy_factory.h", 
       "src/core/ext/filters/client_channel/lb_policy_registry.cc", 
       "src/core/ext/filters/client_channel/lb_policy_registry.h", 
@@ -10120,6 +10120,8 @@
       "src/core/ext/filters/client_channel/resolver_result_parsing.h", 
       "src/core/ext/filters/client_channel/retry_throttle.cc", 
       "src/core/ext/filters/client_channel/retry_throttle.h", 
+      "src/core/ext/filters/client_channel/server_address.cc", 
+      "src/core/ext/filters/client_channel/server_address.h", 
       "src/core/ext/filters/client_channel/subchannel.cc", 
       "src/core/ext/filters/client_channel/subchannel.h", 
       "src/core/ext/filters/client_channel/subchannel_index.cc",