[EventEngine] PosixEventEngine DNS Resolver (#32701)

This PR implements a c-ares based DNS resolver for EventEngine with the reference from the original [grpc_ares_wrapper.h](../blob/master/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h). The PosixEventEngine DNSResolver is implemented on top of that. Tests which use the client channel resolver API ([resolver.h](../blob/master/src/core/lib/resolver/resolver.h#L54)) are ported, namely the [resolver_component_test.cc](../blob/master/test/cpp/naming/resolver_component_test.cc) and the [cancel_ares_query_test.cc](../blob/master/test/cpp/naming/cancel_ares_query_test.cc). The WindowsEventEngine DNSResolver will use the same EventEngine's grpc_ares_wrapper and will be worked on next. The [resolve_address_test.cc](https://github.com/grpc/grpc/blob/master/test/core/iomgr/resolve_address_test.cc) which uses the iomgr [DNSResolver](../blob/master/src/core/lib/iomgr/resolve_address.h#L44) API has been ported to EventEngine's dns_test.cc. That leaves only 2 tests which use iomgr's API, notably the [dns_resolver_cooldown_test.cc](../blob/master/test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc) and the [goaway_server_test.cc](../blob/master/test/core/end2end/goaway_server_test.cc) which probably need to be restructured to use EventEngine DNSResolver (for one thing they override the original grpc_ares_wrapper's free functions). I will try to tackle these in the next step.
2023-07-21 13:24:16 -07:00 · 2023-07-21 13:24:16 -07:00 · a7bf07e86a
parent 04a7b80e98
commit a7bf07e86a
50 changed files with 2097 additions and 56 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -2150,6 +2150,7 @@ add_library(grpc
  src/core/lib/debug/stats.cc
  src/core/lib/debug/stats_data.cc
  src/core/lib/debug/trace.cc
+  src/core/lib/event_engine/ares_resolver.cc
  src/core/lib/event_engine/cf_engine/cf_engine.cc
  src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc
  src/core/lib/event_engine/channel_args_endpoint_config.cc
@ -2855,6 +2856,7 @@ add_library(grpc_unsecure
  src/core/lib/debug/stats.cc
  src/core/lib/debug/stats_data.cc
  src/core/lib/debug/trace.cc
+  src/core/lib/event_engine/ares_resolver.cc
  src/core/lib/event_engine/cf_engine/cf_engine.cc
  src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc
  src/core/lib/event_engine/channel_args_endpoint_config.cc
@ -4391,6 +4393,7 @@ add_library(grpc_authorization_provider
  src/core/lib/debug/stats.cc
  src/core/lib/debug/stats_data.cc
  src/core/lib/debug/trace.cc
+  src/core/lib/event_engine/ares_resolver.cc
  src/core/lib/event_engine/cf_engine/cf_engine.cc
  src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc
  src/core/lib/event_engine/channel_args_endpoint_config.cc
@ -4654,6 +4657,7 @@ target_link_libraries(grpc_authorization_provider
  ${_gRPC_BASELIB_LIBRARIES}
  ${_gRPC_PROTOBUF_LIBRARIES}
  ${_gRPC_ZLIB_LIBRARIES}
+  ${_gRPC_CARES_LIBRARIES}
  ${_gRPC_RE2_LIBRARIES}
  ${_gRPC_ALLTARGETS_LIBRARIES}
  absl::cleanup
@ -12385,6 +12389,7 @@ add_executable(frame_test
  src/core/lib/debug/stats.cc
  src/core/lib/debug/stats_data.cc
  src/core/lib/debug/trace.cc
+  src/core/lib/event_engine/ares_resolver.cc
  src/core/lib/event_engine/cf_engine/cf_engine.cc
  src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc
  src/core/lib/event_engine/channel_args_endpoint_config.cc
@ -12608,6 +12613,7 @@ target_link_libraries(frame_test
  ${_gRPC_BASELIB_LIBRARIES}
  ${_gRPC_PROTOBUF_LIBRARIES}
  ${_gRPC_ZLIB_LIBRARIES}
+  ${_gRPC_CARES_LIBRARIES}
  ${_gRPC_ALLTARGETS_LIBRARIES}
  absl::cleanup
  absl::flat_hash_map
@ -18583,8 +18589,11 @@ if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_POSIX)
    test/core/event_engine/test_suite/posix/oracle_event_engine_posix.cc
    test/core/event_engine/test_suite/posix_event_engine_test.cc
    test/core/event_engine/test_suite/tests/client_test.cc
+    test/core/event_engine/test_suite/tests/dns_test.cc
    test/core/event_engine/test_suite/tests/server_test.cc
    test/core/event_engine/test_suite/tests/timer_test.cc
+    test/core/util/fake_udp_and_tcp_server.cc
+    test/cpp/util/get_grpc_test_runfile_dir.cc
    third_party/googletest/googletest/src/gtest-all.cc
    third_party/googletest/googlemock/src/gmock-all.cc
  )
@ -18614,7 +18623,7 @@ if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_POSIX)
    ${_gRPC_ZLIB_LIBRARIES}
    ${_gRPC_ALLTARGETS_LIBRARIES}
    grpc_unsecure
-    grpc_test_util
+    grpc++_test_util
  )


--- a/2
+++ b/2
@ -1435,6 +1435,7 @@ LIBGRPC_SRC = \
    src/core/lib/debug/stats.cc \
    src/core/lib/debug/stats_data.cc \
    src/core/lib/debug/trace.cc \
+    src/core/lib/event_engine/ares_resolver.cc \
    src/core/lib/event_engine/cf_engine/cf_engine.cc \
    src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc \
    src/core/lib/event_engine/channel_args_endpoint_config.cc \
@ -1993,6 +1994,7 @@ LIBGRPC_UNSECURE_SRC = \
    src/core/lib/debug/stats.cc \
    src/core/lib/debug/stats_data.cc \
    src/core/lib/debug/trace.cc \
+    src/core/lib/event_engine/ares_resolver.cc \
    src/core/lib/event_engine/cf_engine/cf_engine.cc \
    src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc \
    src/core/lib/event_engine/channel_args_endpoint_config.cc \
--- a/Package.swift
+++ b/Package.swift
@ -1057,6 +1057,8 @@ let package = Package(
        "src/core/lib/debug/stats_data.h",
        "src/core/lib/debug/trace.cc",
        "src/core/lib/debug/trace.h",
+        "src/core/lib/event_engine/ares_resolver.cc",
+        "src/core/lib/event_engine/ares_resolver.h",
        "src/core/lib/event_engine/cf_engine/cf_engine.cc",
        "src/core/lib/event_engine/cf_engine/cf_engine.h",
        "src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc",
@ -1072,6 +1074,7 @@ let package = Package(
        "src/core/lib/event_engine/event_engine.cc",
        "src/core/lib/event_engine/forkable.cc",
        "src/core/lib/event_engine/forkable.h",
+        "src/core/lib/event_engine/grpc_polled_fd.h",
        "src/core/lib/event_engine/handle_containers.h",
        "src/core/lib/event_engine/memory_allocator.cc",
        "src/core/lib/event_engine/memory_allocator_factory.h",
@ -1084,6 +1087,7 @@ let package = Package(
        "src/core/lib/event_engine/posix_engine/event_poller.h",
        "src/core/lib/event_engine/posix_engine/event_poller_posix_default.cc",
        "src/core/lib/event_engine/posix_engine/event_poller_posix_default.h",
+        "src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h",
        "src/core/lib/event_engine/posix_engine/internal_errqueue.cc",
        "src/core/lib/event_engine/posix_engine/internal_errqueue.h",
        "src/core/lib/event_engine/posix_engine/lockfree_event.cc",
--- a/bazel/experiments.bzl
+++ b/bazel/experiments.bzl
@ -20,6 +20,9 @@ EXPERIMENTS = {
    "dbg": {
    },
    "off": {
+        "cancel_ares_query_test": [
+            "event_engine_dns",
+        ],
        "census_test": [
            "transport_supplies_client_latency",
        ],
@ -55,6 +58,9 @@ EXPERIMENTS = {
        "logging_test": [
            "promise_based_server_call",
        ],
+        "resolver_component_tests_runner_invoker": [
+            "event_engine_dns",
+        ],
        "resource_quota_test": [
            "free_large_allocator",
            "memory_pressure_controller",
--- a/build_autogenerated.yaml
+++ b/build_autogenerated.yaml
@ -680,6 +680,7 @@ libs:
  - src/core/lib/debug/stats.h
  - src/core/lib/debug/stats_data.h
  - src/core/lib/debug/trace.h
+  - src/core/lib/event_engine/ares_resolver.h
  - src/core/lib/event_engine/cf_engine/cf_engine.h
  - src/core/lib/event_engine/cf_engine/cfstream_endpoint.h
  - src/core/lib/event_engine/cf_engine/cftype_unique_ref.h
@ -688,6 +689,7 @@ libs:
  - src/core/lib/event_engine/default_event_engine.h
  - src/core/lib/event_engine/default_event_engine_factory.h
  - src/core/lib/event_engine/forkable.h
+  - src/core/lib/event_engine/grpc_polled_fd.h
  - src/core/lib/event_engine/handle_containers.h
  - src/core/lib/event_engine/memory_allocator_factory.h
  - src/core/lib/event_engine/poller.h
@ -696,6 +698,7 @@ libs:
  - src/core/lib/event_engine/posix_engine/ev_poll_posix.h
  - src/core/lib/event_engine/posix_engine/event_poller.h
  - src/core/lib/event_engine/posix_engine/event_poller_posix_default.h
+  - src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h
  - src/core/lib/event_engine/posix_engine/internal_errqueue.h
  - src/core/lib/event_engine/posix_engine/lockfree_event.h
  - src/core/lib/event_engine/posix_engine/posix_endpoint.h
@ -1492,6 +1495,7 @@ libs:
  - src/core/lib/debug/stats.cc
  - src/core/lib/debug/stats_data.cc
  - src/core/lib/debug/trace.cc
+  - src/core/lib/event_engine/ares_resolver.cc
  - src/core/lib/event_engine/cf_engine/cf_engine.cc
  - src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc
  - src/core/lib/event_engine/channel_args_endpoint_config.cc
@ -2070,6 +2074,7 @@ libs:
  - src/core/lib/debug/stats.h
  - src/core/lib/debug/stats_data.h
  - src/core/lib/debug/trace.h
+  - src/core/lib/event_engine/ares_resolver.h
  - src/core/lib/event_engine/cf_engine/cf_engine.h
  - src/core/lib/event_engine/cf_engine/cfstream_endpoint.h
  - src/core/lib/event_engine/cf_engine/cftype_unique_ref.h
@ -2078,6 +2083,7 @@ libs:
  - src/core/lib/event_engine/default_event_engine.h
  - src/core/lib/event_engine/default_event_engine_factory.h
  - src/core/lib/event_engine/forkable.h
+  - src/core/lib/event_engine/grpc_polled_fd.h
  - src/core/lib/event_engine/handle_containers.h
  - src/core/lib/event_engine/memory_allocator_factory.h
  - src/core/lib/event_engine/poller.h
@ -2086,6 +2092,7 @@ libs:
  - src/core/lib/event_engine/posix_engine/ev_poll_posix.h
  - src/core/lib/event_engine/posix_engine/event_poller.h
  - src/core/lib/event_engine/posix_engine/event_poller_posix_default.h
+  - src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h
  - src/core/lib/event_engine/posix_engine/internal_errqueue.h
  - src/core/lib/event_engine/posix_engine/lockfree_event.h
  - src/core/lib/event_engine/posix_engine/posix_endpoint.h
@ -2489,6 +2496,7 @@ libs:
  - src/core/lib/debug/stats.cc
  - src/core/lib/debug/stats_data.cc
  - src/core/lib/debug/trace.cc
+  - src/core/lib/event_engine/ares_resolver.cc
  - src/core/lib/event_engine/cf_engine/cf_engine.cc
  - src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc
  - src/core/lib/event_engine/channel_args_endpoint_config.cc
@ -3573,6 +3581,7 @@ libs:
  - src/core/lib/debug/stats.h
  - src/core/lib/debug/stats_data.h
  - src/core/lib/debug/trace.h
+  - src/core/lib/event_engine/ares_resolver.h
  - src/core/lib/event_engine/cf_engine/cf_engine.h
  - src/core/lib/event_engine/cf_engine/cfstream_endpoint.h
  - src/core/lib/event_engine/cf_engine/cftype_unique_ref.h
@ -3581,6 +3590,7 @@ libs:
  - src/core/lib/event_engine/default_event_engine.h
  - src/core/lib/event_engine/default_event_engine_factory.h
  - src/core/lib/event_engine/forkable.h
+  - src/core/lib/event_engine/grpc_polled_fd.h
  - src/core/lib/event_engine/handle_containers.h
  - src/core/lib/event_engine/memory_allocator_factory.h
  - src/core/lib/event_engine/poller.h
@ -3589,6 +3599,7 @@ libs:
  - src/core/lib/event_engine/posix_engine/ev_poll_posix.h
  - src/core/lib/event_engine/posix_engine/event_poller.h
  - src/core/lib/event_engine/posix_engine/event_poller_posix_default.h
+  - src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h
  - src/core/lib/event_engine/posix_engine/internal_errqueue.h
  - src/core/lib/event_engine/posix_engine/lockfree_event.h
  - src/core/lib/event_engine/posix_engine/posix_endpoint.h
@ -3873,6 +3884,7 @@ libs:
  - src/core/lib/debug/stats.cc
  - src/core/lib/debug/stats_data.cc
  - src/core/lib/debug/trace.cc
+  - src/core/lib/event_engine/ares_resolver.cc
  - src/core/lib/event_engine/cf_engine/cf_engine.cc
  - src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc
  - src/core/lib/event_engine/channel_args_endpoint_config.cc
@ -8071,6 +8083,7 @@ targets:
  - src/core/lib/debug/stats.h
  - src/core/lib/debug/stats_data.h
  - src/core/lib/debug/trace.h
+  - src/core/lib/event_engine/ares_resolver.h
  - src/core/lib/event_engine/cf_engine/cf_engine.h
  - src/core/lib/event_engine/cf_engine/cfstream_endpoint.h
  - src/core/lib/event_engine/cf_engine/cftype_unique_ref.h
@ -8079,6 +8092,7 @@ targets:
  - src/core/lib/event_engine/default_event_engine.h
  - src/core/lib/event_engine/default_event_engine_factory.h
  - src/core/lib/event_engine/forkable.h
+  - src/core/lib/event_engine/grpc_polled_fd.h
  - src/core/lib/event_engine/handle_containers.h
  - src/core/lib/event_engine/memory_allocator_factory.h
  - src/core/lib/event_engine/poller.h
@ -8087,6 +8101,7 @@ targets:
  - src/core/lib/event_engine/posix_engine/ev_poll_posix.h
  - src/core/lib/event_engine/posix_engine/event_poller.h
  - src/core/lib/event_engine/posix_engine/event_poller_posix_default.h
+  - src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h
  - src/core/lib/event_engine/posix_engine/internal_errqueue.h
  - src/core/lib/event_engine/posix_engine/lockfree_event.h
  - src/core/lib/event_engine/posix_engine/posix_endpoint.h
@ -8353,6 +8368,7 @@ targets:
  - src/core/lib/debug/stats.cc
  - src/core/lib/debug/stats_data.cc
  - src/core/lib/debug/trace.cc
+  - src/core/lib/event_engine/ares_resolver.cc
  - src/core/lib/event_engine/cf_engine/cf_engine.cc
  - src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc
  - src/core/lib/event_engine/channel_args_endpoint_config.cc
@ -11427,19 +11443,25 @@ targets:
  - test/core/event_engine/test_suite/event_engine_test_framework.h
  - test/core/event_engine/test_suite/posix/oracle_event_engine_posix.h
  - test/core/event_engine/test_suite/tests/client_test.h
+  - test/core/event_engine/test_suite/tests/dns_test.h
  - test/core/event_engine/test_suite/tests/server_test.h
  - test/core/event_engine/test_suite/tests/timer_test.h
+  - test/core/util/fake_udp_and_tcp_server.h
+  - test/cpp/util/get_grpc_test_runfile_dir.h
  src:
  - test/core/event_engine/event_engine_test_utils.cc
  - test/core/event_engine/test_suite/event_engine_test_framework.cc
  - test/core/event_engine/test_suite/posix/oracle_event_engine_posix.cc
  - test/core/event_engine/test_suite/posix_event_engine_test.cc
  - test/core/event_engine/test_suite/tests/client_test.cc
+  - test/core/event_engine/test_suite/tests/dns_test.cc
  - test/core/event_engine/test_suite/tests/server_test.cc
  - test/core/event_engine/test_suite/tests/timer_test.cc
+  - test/core/util/fake_udp_and_tcp_server.cc
+  - test/cpp/util/get_grpc_test_runfile_dir.cc
  deps:
  - grpc_unsecure
-  - grpc_test_util
+  - grpc++_test_util
  platforms:
  - linux
  - posix
--- a/config.m4
+++ b/config.m4
@ -517,6 +517,7 @@ if test "$PHP_GRPC" != "no"; then
    src/core/lib/debug/stats.cc \
    src/core/lib/debug/stats_data.cc \
    src/core/lib/debug/trace.cc \
+    src/core/lib/event_engine/ares_resolver.cc \
    src/core/lib/event_engine/cf_engine/cf_engine.cc \
    src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc \
    src/core/lib/event_engine/channel_args_endpoint_config.cc \
--- a/config.w32
+++ b/config.w32
@ -482,6 +482,7 @@ if (PHP_GRPC != "no") {
    "src\\core\\lib\\debug\\stats.cc " +
    "src\\core\\lib\\debug\\stats_data.cc " +
    "src\\core\\lib\\debug\\trace.cc " +
+    "src\\core\\lib\\event_engine\\ares_resolver.cc " +
    "src\\core\\lib\\event_engine\\cf_engine\\cf_engine.cc " +
    "src\\core\\lib\\event_engine\\cf_engine\\cfstream_endpoint.cc " +
    "src\\core\\lib\\event_engine\\channel_args_endpoint_config.cc " +
--- a/gRPC-C++.podspec
+++ b/gRPC-C++.podspec
@ -752,6 +752,7 @@ Pod::Spec.new do |s|
                      'src/core/lib/debug/stats.h',
                      'src/core/lib/debug/stats_data.h',
                      'src/core/lib/debug/trace.h',
+                      'src/core/lib/event_engine/ares_resolver.h',
                      'src/core/lib/event_engine/cf_engine/cf_engine.h',
                      'src/core/lib/event_engine/cf_engine/cfstream_endpoint.h',
                      'src/core/lib/event_engine/cf_engine/cftype_unique_ref.h',
@ -760,6 +761,7 @@ Pod::Spec.new do |s|
                      'src/core/lib/event_engine/default_event_engine.h',
                      'src/core/lib/event_engine/default_event_engine_factory.h',
                      'src/core/lib/event_engine/forkable.h',
+                      'src/core/lib/event_engine/grpc_polled_fd.h',
                      'src/core/lib/event_engine/handle_containers.h',
                      'src/core/lib/event_engine/memory_allocator_factory.h',
                      'src/core/lib/event_engine/poller.h',
@ -768,6 +770,7 @@ Pod::Spec.new do |s|
                      'src/core/lib/event_engine/posix_engine/ev_poll_posix.h',
                      'src/core/lib/event_engine/posix_engine/event_poller.h',
                      'src/core/lib/event_engine/posix_engine/event_poller_posix_default.h',
+                      'src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h',
                      'src/core/lib/event_engine/posix_engine/internal_errqueue.h',
                      'src/core/lib/event_engine/posix_engine/lockfree_event.h',
                      'src/core/lib/event_engine/posix_engine/posix_endpoint.h',
@ -1798,6 +1801,7 @@ Pod::Spec.new do |s|
                              'src/core/lib/debug/stats.h',
                              'src/core/lib/debug/stats_data.h',
                              'src/core/lib/debug/trace.h',
+                              'src/core/lib/event_engine/ares_resolver.h',
                              'src/core/lib/event_engine/cf_engine/cf_engine.h',
                              'src/core/lib/event_engine/cf_engine/cfstream_endpoint.h',
                              'src/core/lib/event_engine/cf_engine/cftype_unique_ref.h',
@ -1806,6 +1810,7 @@ Pod::Spec.new do |s|
                              'src/core/lib/event_engine/default_event_engine.h',
                              'src/core/lib/event_engine/default_event_engine_factory.h',
                              'src/core/lib/event_engine/forkable.h',
+                              'src/core/lib/event_engine/grpc_polled_fd.h',
                              'src/core/lib/event_engine/handle_containers.h',
                              'src/core/lib/event_engine/memory_allocator_factory.h',
                              'src/core/lib/event_engine/poller.h',
@ -1814,6 +1819,7 @@ Pod::Spec.new do |s|
                              'src/core/lib/event_engine/posix_engine/ev_poll_posix.h',
                              'src/core/lib/event_engine/posix_engine/event_poller.h',
                              'src/core/lib/event_engine/posix_engine/event_poller_posix_default.h',
+                              'src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h',
                              'src/core/lib/event_engine/posix_engine/internal_errqueue.h',
                              'src/core/lib/event_engine/posix_engine/lockfree_event.h',
                              'src/core/lib/event_engine/posix_engine/posix_endpoint.h',
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@ -1158,6 +1158,8 @@ Pod::Spec.new do |s|
                      'src/core/lib/debug/stats_data.h',
                      'src/core/lib/debug/trace.cc',
                      'src/core/lib/debug/trace.h',
+                      'src/core/lib/event_engine/ares_resolver.cc',
+                      'src/core/lib/event_engine/ares_resolver.h',
                      'src/core/lib/event_engine/cf_engine/cf_engine.cc',
                      'src/core/lib/event_engine/cf_engine/cf_engine.h',
                      'src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc',
@ -1173,6 +1175,7 @@ Pod::Spec.new do |s|
                      'src/core/lib/event_engine/event_engine.cc',
                      'src/core/lib/event_engine/forkable.cc',
                      'src/core/lib/event_engine/forkable.h',
+                      'src/core/lib/event_engine/grpc_polled_fd.h',
                      'src/core/lib/event_engine/handle_containers.h',
                      'src/core/lib/event_engine/memory_allocator.cc',
                      'src/core/lib/event_engine/memory_allocator_factory.h',
@ -1185,6 +1188,7 @@ Pod::Spec.new do |s|
                      'src/core/lib/event_engine/posix_engine/event_poller.h',
                      'src/core/lib/event_engine/posix_engine/event_poller_posix_default.cc',
                      'src/core/lib/event_engine/posix_engine/event_poller_posix_default.h',
+                      'src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h',
                      'src/core/lib/event_engine/posix_engine/internal_errqueue.cc',
                      'src/core/lib/event_engine/posix_engine/internal_errqueue.h',
                      'src/core/lib/event_engine/posix_engine/lockfree_event.cc',
@ -2529,6 +2533,7 @@ Pod::Spec.new do |s|
                              'src/core/lib/debug/stats.h',
                              'src/core/lib/debug/stats_data.h',
                              'src/core/lib/debug/trace.h',
+                              'src/core/lib/event_engine/ares_resolver.h',
                              'src/core/lib/event_engine/cf_engine/cf_engine.h',
                              'src/core/lib/event_engine/cf_engine/cfstream_endpoint.h',
                              'src/core/lib/event_engine/cf_engine/cftype_unique_ref.h',
@ -2537,6 +2542,7 @@ Pod::Spec.new do |s|
                              'src/core/lib/event_engine/default_event_engine.h',
                              'src/core/lib/event_engine/default_event_engine_factory.h',
                              'src/core/lib/event_engine/forkable.h',
+                              'src/core/lib/event_engine/grpc_polled_fd.h',
                              'src/core/lib/event_engine/handle_containers.h',
                              'src/core/lib/event_engine/memory_allocator_factory.h',
                              'src/core/lib/event_engine/poller.h',
@ -2545,6 +2551,7 @@ Pod::Spec.new do |s|
                              'src/core/lib/event_engine/posix_engine/ev_poll_posix.h',
                              'src/core/lib/event_engine/posix_engine/event_poller.h',
                              'src/core/lib/event_engine/posix_engine/event_poller_posix_default.h',
+                              'src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h',
                              'src/core/lib/event_engine/posix_engine/internal_errqueue.h',
                              'src/core/lib/event_engine/posix_engine/lockfree_event.h',
                              'src/core/lib/event_engine/posix_engine/posix_endpoint.h',
--- a/grpc.gemspec
+++ b/grpc.gemspec
@ -1063,6 +1063,8 @@ Gem::Specification.new do |s|
  s.files += %w( src/core/lib/debug/stats_data.h )
  s.files += %w( src/core/lib/debug/trace.cc )
  s.files += %w( src/core/lib/debug/trace.h )
+  s.files += %w( src/core/lib/event_engine/ares_resolver.cc )
+  s.files += %w( src/core/lib/event_engine/ares_resolver.h )
  s.files += %w( src/core/lib/event_engine/cf_engine/cf_engine.cc )
  s.files += %w( src/core/lib/event_engine/cf_engine/cf_engine.h )
  s.files += %w( src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc )
@ -1078,6 +1080,7 @@ Gem::Specification.new do |s|
  s.files += %w( src/core/lib/event_engine/event_engine.cc )
  s.files += %w( src/core/lib/event_engine/forkable.cc )
  s.files += %w( src/core/lib/event_engine/forkable.h )
+  s.files += %w( src/core/lib/event_engine/grpc_polled_fd.h )
  s.files += %w( src/core/lib/event_engine/handle_containers.h )
  s.files += %w( src/core/lib/event_engine/memory_allocator.cc )
  s.files += %w( src/core/lib/event_engine/memory_allocator_factory.h )
@ -1090,6 +1093,7 @@ Gem::Specification.new do |s|
  s.files += %w( src/core/lib/event_engine/posix_engine/event_poller.h )
  s.files += %w( src/core/lib/event_engine/posix_engine/event_poller_posix_default.cc )
  s.files += %w( src/core/lib/event_engine/posix_engine/event_poller_posix_default.h )
+  s.files += %w( src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h )
  s.files += %w( src/core/lib/event_engine/posix_engine/internal_errqueue.cc )
  s.files += %w( src/core/lib/event_engine/posix_engine/internal_errqueue.h )
  s.files += %w( src/core/lib/event_engine/posix_engine/lockfree_event.cc )
--- a/grpc.gyp
+++ b/grpc.gyp
@ -739,6 +739,7 @@
        'src/core/lib/debug/stats.cc',
        'src/core/lib/debug/stats_data.cc',
        'src/core/lib/debug/trace.cc',
+        'src/core/lib/event_engine/ares_resolver.cc',
        'src/core/lib/event_engine/cf_engine/cf_engine.cc',
        'src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc',
        'src/core/lib/event_engine/channel_args_endpoint_config.cc',
@ -1237,6 +1238,7 @@
        'src/core/lib/debug/stats.cc',
        'src/core/lib/debug/stats_data.cc',
        'src/core/lib/debug/trace.cc',
+        'src/core/lib/event_engine/ares_resolver.cc',
        'src/core/lib/event_engine/cf_engine/cf_engine.cc',
        'src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc',
        'src/core/lib/event_engine/channel_args_endpoint_config.cc',
@ -1757,6 +1759,7 @@
        'src/core/lib/debug/stats.cc',
        'src/core/lib/debug/stats_data.cc',
        'src/core/lib/debug/trace.cc',
+        'src/core/lib/event_engine/ares_resolver.cc',
        'src/core/lib/event_engine/cf_engine/cf_engine.cc',
        'src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc',
        'src/core/lib/event_engine/channel_args_endpoint_config.cc',
--- a/include/grpc/event_engine/event_engine.h
+++ b/include/grpc/event_engine/event_engine.h
@ -365,7 +365,6 @@ class EventEngine : public std::enable_shared_from_this<EventEngine> {
    /// lookup. Implementations should pass the appropriate statuses to the
    /// callback. For example, callbacks might expect to receive CANCELLED or
    /// NOT_FOUND.
-    ///
    virtual void LookupHostname(LookupHostnameCallback on_resolve,
                                absl::string_view name,
                                absl::string_view default_port) = 0;
--- a/package.xml
+++ b/package.xml
@ -1045,6 +1045,8 @@
    <file baseinstalldir="/" name="src/core/lib/debug/stats_data.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/debug/trace.cc" role="src" />
    <file baseinstalldir="/" name="src/core/lib/debug/trace.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/event_engine/ares_resolver.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/event_engine/ares_resolver.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/cf_engine/cf_engine.cc" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/cf_engine/cf_engine.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc" role="src" />
@ -1060,6 +1062,7 @@
    <file baseinstalldir="/" name="src/core/lib/event_engine/event_engine.cc" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/forkable.cc" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/forkable.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/event_engine/grpc_polled_fd.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/handle_containers.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/memory_allocator.cc" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/memory_allocator_factory.h" role="src" />
@ -1072,6 +1075,7 @@
    <file baseinstalldir="/" name="src/core/lib/event_engine/posix_engine/event_poller.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/posix_engine/event_poller_posix_default.cc" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/posix_engine/event_poller_posix_default.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/posix_engine/internal_errqueue.cc" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/posix_engine/internal_errqueue.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/event_engine/posix_engine/lockfree_event.cc" role="src" />
--- a/src/core/BUILD
+++ b/src/core/BUILD
@ -1975,6 +1975,7 @@ grpc_cc_library(
        "absl/strings",
    ],
    deps = [
+        "ares_resolver",
        "event_engine_common",
        "event_engine_poller",
        "event_engine_tcp_socket_utils",
@ -1996,6 +1997,7 @@ grpc_cc_library(
        "//:event_engine_base_hdrs",
        "//:gpr",
        "//:grpc_trace",
+        "//:orphanable",
    ],
 )

@ -2298,6 +2300,49 @@ grpc_cc_library(
    ],
 )

+grpc_cc_library(
+    name = "ares_resolver",
+    srcs = [
+        "lib/event_engine/ares_resolver.cc",
+    ],
+    hdrs = [
+        "lib/event_engine/ares_resolver.h",
+        "lib/event_engine/grpc_polled_fd.h",
+        "lib/event_engine/posix_engine/grpc_polled_fd_posix.h",
+    ],
+    external_deps = [
+        "absl/base:core_headers",
+        "absl/container:flat_hash_map",
+        "absl/functional:any_invocable",
+        "absl/hash",
+        "absl/status",
+        "absl/status:statusor",
+        "absl/strings",
+        "absl/strings:str_format",
+        "absl/types:optional",
+        "absl/types:variant",
+        "cares",
+    ],
+    deps = [
+        "error",
+        "event_engine_time_util",
+        "grpc_sockaddr",
+        "iomgr_port",
+        "posix_event_engine_closure",
+        "posix_event_engine_event_poller",
+        "posix_event_engine_tcp_socket_utils",
+        "resolved_address",
+        "//:debug_location",
+        "//:event_engine_base_hdrs",
+        "//:gpr",
+        "//:grpc_trace",
+        "//:orphanable",
+        "//:parse_address",
+        "//:ref_counted_ptr",
+        "//:sockaddr_utils",
+    ],
+)
+
 grpc_cc_library(
    name = "channel_args_preconditioning",
    srcs = [
@ -5153,6 +5198,7 @@ grpc_cc_library(
        "validation_errors",
        "//:backoff",
        "//:debug_location",
+        "//:exec_ctx",
        "//:gpr",
        "//:gpr_platform",
        "//:grpc_base",
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
@ -510,9 +510,9 @@ void grpc_ares_ev_driver_start_locked(grpc_ares_ev_driver* ev_driver)
                  &ev_driver->on_ares_backup_poll_alarm_locked);
 }

-static void noop_inject_channel_config(ares_channel /*channel*/) {}
+static void noop_inject_channel_config(ares_channel* /*channel*/) {}

-void (*grpc_ares_test_only_inject_config)(ares_channel channel) =
+void (*grpc_ares_test_only_inject_config)(ares_channel* channel) =
    noop_inject_channel_config;

 grpc_error_handle grpc_ares_ev_driver_create_locked(
@ -524,7 +524,7 @@ grpc_error_handle grpc_ares_ev_driver_create_locked(
  memset(&opts, 0, sizeof(opts));
  opts.flags |= ARES_FLAG_STAYOPEN;
  int status = ares_init_options(&(*ev_driver)->channel, &opts, ARES_OPT_FLAGS);
-  grpc_ares_test_only_inject_config((*ev_driver)->channel);
+  grpc_ares_test_only_inject_config(&(*ev_driver)->channel);
  GRPC_CARES_TRACE_LOG("request:%p grpc_ares_ev_driver_create_locked", request);
  if (status != ARES_SUCCESS) {
    grpc_error_handle err = GRPC_ERROR_CREATE(absl::StrCat(
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h
@ -131,6 +131,6 @@ void grpc_cares_wrapper_address_sorting_sort(
    const grpc_ares_request* request, grpc_core::ServerAddressList* addresses);

 // Exposed in this header for C-core tests only
-extern void (*grpc_ares_test_only_inject_config)(ares_channel channel);
+extern void (*grpc_ares_test_only_inject_config)(ares_channel* channel);

 #endif  // GRPC_SRC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_WRAPPER_H
--- a/src/core/ext/filters/client_channel/resolver/dns/event_engine/event_engine_client_channel_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/event_engine/event_engine_client_channel_resolver.cc
@ -22,7 +22,6 @@
 #include <chrono>
 #include <memory>
 #include <string>
-#include <type_traits>
 #include <utility>
 #include <vector>

@ -51,6 +50,7 @@
 #include "src/core/lib/gprpp/sync.h"
 #include "src/core/lib/gprpp/time.h"
 #include "src/core/lib/gprpp/validation_errors.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/resolver/resolver.h"
 #include "src/core/lib/resolver/resolver_factory.h"
@ -231,8 +231,12 @@ EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
  is_hostname_inflight_ = true;
  event_engine_resolver_->LookupHostname(
      [self = Ref(DEBUG_LOCATION, "OnHostnameResolved")](
-          absl::StatusOr<std::vector<EventEngine::ResolvedAddress>> addresses) {
+          absl::StatusOr<std::vector<EventEngine::ResolvedAddress>>
+              addresses) mutable {
+        ApplicationCallbackExecCtx callback_exec_ctx;
+        ExecCtx exec_ctx;
        self->OnHostnameResolved(std::move(addresses));
+        self.reset();
      },
      resolver_->name_to_resolve(), kDefaultSecurePort);
  if (resolver_->enable_srv_queries_) {
@ -243,8 +247,13 @@ EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
    event_engine_resolver_->LookupSRV(
        [self = Ref(DEBUG_LOCATION, "OnSRVResolved")](
            absl::StatusOr<std::vector<EventEngine::DNSResolver::SRVRecord>>
-                srv_records) { self->OnSRVResolved(std::move(srv_records)); },
-        resolver_->name_to_resolve());
+                srv_records) mutable {
+          ApplicationCallbackExecCtx callback_exec_ctx;
+          ExecCtx exec_ctx;
+          self->OnSRVResolved(std::move(srv_records));
+          self.reset();
+        },
+        absl::StrCat("_grpclb._tcp.", resolver_->name_to_resolve()));
  }
  if (resolver_->request_service_config_) {
    GRPC_EVENT_ENGINE_RESOLVER_TRACE(
@ -253,8 +262,11 @@ EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
    is_txt_inflight_ = true;
    event_engine_resolver_->LookupTXT(
        [self = Ref(DEBUG_LOCATION, "OnTXTResolved")](
-            absl::StatusOr<std::vector<std::string>> service_config) {
+            absl::StatusOr<std::vector<std::string>> service_config) mutable {
+          ApplicationCallbackExecCtx callback_exec_ctx;
+          ExecCtx exec_ctx;
          self->OnTXTResolved(std::move(service_config));
+          self.reset();
        },
        absl::StrCat("_grpc_config.", resolver_->name_to_resolve()));
  }
@ -263,8 +275,12 @@ EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
                     ? EventEngine::Duration::max()
                     : resolver_->query_timeout_ms_;
  timeout_handle_ = resolver_->event_engine_->RunAfter(
-      timeout,
-      [self = Ref(DEBUG_LOCATION, "OnTimeout")]() { self->OnTimeout(); });
+      timeout, [self = Ref(DEBUG_LOCATION, "OnTimeout")]() mutable {
+        ApplicationCallbackExecCtx callback_exec_ctx;
+        ExecCtx exec_ctx;
+        self->OnTimeout();
+        self.reset();
+      });
 }

 EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
@ -300,10 +316,11 @@ void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
 void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
    OnHostnameResolved(absl::StatusOr<std::vector<EventEngine::ResolvedAddress>>
                           new_addresses) {
-  ValidationErrors::ScopedField field(&errors_, "hostname lookup");
  absl::optional<Resolver::Result> result;
  {
    MutexLock lock(&on_resolved_mu_);
+    // Make sure field destroys before cleanup.
+    ValidationErrors::ScopedField field(&errors_, "hostname lookup");
    if (orphaned_) return;
    is_hostname_inflight_ = false;
    if (!new_addresses.ok()) {
@ -325,7 +342,6 @@ void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
    OnSRVResolved(
        absl::StatusOr<std::vector<EventEngine::DNSResolver::SRVRecord>>
            srv_records) {
-  ValidationErrors::ScopedField field(&errors_, "srv lookup");
  absl::optional<Resolver::Result> result;
  auto cleanup = absl::MakeCleanup([&]() {
    if (result.has_value()) {
@ -333,6 +349,8 @@ void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
    }
  });
  MutexLock lock(&on_resolved_mu_);
+  // Make sure field destroys before cleanup.
+  ValidationErrors::ScopedField field(&errors_, "srv lookup");
  if (orphaned_) return;
  is_srv_inflight_ = false;
  if (!srv_records.ok()) {
@ -359,12 +377,15 @@ void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
        resolver_.get(), srv_record.host.c_str(), srv_record.port);
    ++number_of_balancer_hostnames_initiated_;
    event_engine_resolver_->LookupHostname(
-        [host = std::move(srv_record.host),
+        [host = srv_record.host,
         self = Ref(DEBUG_LOCATION, "OnBalancerHostnamesResolved")](
            absl::StatusOr<std::vector<EventEngine::ResolvedAddress>>
                new_balancer_addresses) mutable {
+          ApplicationCallbackExecCtx callback_exec_ctx;
+          ExecCtx exec_ctx;
          self->OnBalancerHostnamesResolved(std::move(host),
                                            std::move(new_balancer_addresses));
+          self.reset();
        },
        srv_record.host, std::to_string(srv_record.port));
  }
@ -375,8 +396,6 @@ void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
        std::string authority,
        absl::StatusOr<std::vector<EventEngine::ResolvedAddress>>
            new_balancer_addresses) {
-  ValidationErrors::ScopedField field(
-      &errors_, absl::StrCat("balancer lookup for ", authority));
  absl::optional<Resolver::Result> result;
  auto cleanup = absl::MakeCleanup([&]() {
    if (result.has_value()) {
@ -384,6 +403,9 @@ void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
    }
  });
  MutexLock lock(&on_resolved_mu_);
+  // Make sure field destroys before cleanup.
+  ValidationErrors::ScopedField field(
+      &errors_, absl::StrCat("balancer lookup for ", authority));
  if (orphaned_) return;
  ++number_of_balancer_hostnames_resolved_;
  if (!new_balancer_addresses.ok()) {
@ -405,10 +427,11 @@ void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::

 void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
    OnTXTResolved(absl::StatusOr<std::vector<std::string>> service_config) {
-  ValidationErrors::ScopedField field(&errors_, "txt lookup");
  absl::optional<Resolver::Result> result;
  {
    MutexLock lock(&on_resolved_mu_);
+    // Make sure field destroys before cleanup.
+    ValidationErrors::ScopedField field(&errors_, "txt lookup");
    if (orphaned_) return;
    GPR_ASSERT(is_txt_inflight_);
    is_txt_inflight_ = false;
@ -424,8 +447,12 @@ void EventEngineClientChannelDNSResolver::EventEngineDNSRequestWrapper::
                                       s, kServiceConfigAttributePrefix);
                                 });
      if (result != service_config->end()) {
+        // Found a service config record.
        service_config_json_ =
            result->substr(kServiceConfigAttributePrefix.size());
+        GRPC_EVENT_ENGINE_RESOLVER_TRACE(
+            "DNSResolver::%p found service config: %s",
+            event_engine_resolver_.get(), service_config_json_->c_str());
      } else {
        service_config_json_ = absl::UnavailableError(absl::StrCat(
            "failed to find attribute prefix: ", kServiceConfigAttributePrefix,
--- a/src/core/ext/filters/client_channel/resolver/polling_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/polling_resolver.cc
@ -159,7 +159,7 @@ void PollingResolver::OnRequestCompleteLocked(Result result) {
    if (GPR_UNLIKELY(tracer_ != nullptr && tracer_->enabled())) {
      gpr_log(GPR_INFO,
              "[polling resolver %p] returning result: "
-              "addresses=%s, service_config=%s",
+              "addresses=%s, service_config=%s, resolution_note=%s",
              this,
              result.addresses.ok()
                  ? absl::StrCat("<", result.addresses->size(), " addresses>")
@ -170,7 +170,8 @@ void PollingResolver::OnRequestCompleteLocked(Result result) {
                         ? "<null>"
                         : std::string((*result.service_config)->json_string())
                               .c_str())
-                  : result.service_config.status().ToString().c_str());
+                  : result.service_config.status().ToString().c_str(),
+              result.resolution_note.c_str());
    }
    GPR_ASSERT(result.result_health_callback == nullptr);
    RefCountedPtr<PollingResolver> self =
--- a/src/core/lib/event_engine/ares_resolver.cc
+++ b/src/core/lib/event_engine/ares_resolver.cc
@ -0,0 +1,705 @@
+// Copyright 2023 The 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/lib/event_engine/ares_resolver.h"
+
+#include <stdint.h>
+
+#include <string>
+#include <vector>
+
+#include "src/core/lib/iomgr/port.h"
+
+// IWYU pragma: no_include <arpa/inet.h>
+// IWYU pragma: no_include <arpa/nameser.h>
+// IWYU pragma: no_include <inttypes.h>
+// IWYU pragma: no_include <netdb.h>
+// IWYU pragma: no_include <netinet/in.h>
+// IWYU pragma: no_include <stdlib.h>
+// IWYU pragma: no_include <sys/socket.h>
+// IWYU pragma: no_include <ratio>
+
+#if GRPC_ARES == 1
+
+#include <ares_nameser.h>
+#include <string.h>
+
+#include <algorithm>
+#include <chrono>
+#include <initializer_list>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#include "absl/functional/any_invocable.h"
+#include "absl/hash/hash.h"
+#include "absl/strings/match.h"
+#include "absl/strings/numbers.h"
+#include "absl/strings/str_cat.h"
+#include "absl/strings/str_format.h"
+#include "absl/types/optional.h"
+
+#include <grpc/event_engine/event_engine.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/address_utils/parse_address.h"
+#include "src/core/lib/address_utils/sockaddr_utils.h"
+#include "src/core/lib/event_engine/grpc_polled_fd.h"
+#include "src/core/lib/event_engine/time_util.h"
+#include "src/core/lib/gprpp/debug_location.h"
+#include "src/core/lib/gprpp/host_port.h"
+#include "src/core/lib/gprpp/ref_counted_ptr.h"
+#include "src/core/lib/iomgr/resolved_address.h"
+#include "src/core/lib/iomgr/sockaddr.h"
+#ifdef GRPC_POSIX_SOCKET_ARES_EV_DRIVER
+#include "src/core/lib/event_engine/posix_engine/tcp_socket_utils.h"
+#endif
+
+namespace grpc_event_engine {
+namespace experimental {
+
+grpc_core::TraceFlag grpc_trace_ares_resolver(false, "cares_resolver");
+
+namespace {
+
+absl::Status AresStatusToAbslStatus(int status, absl::string_view error_msg) {
+  switch (status) {
+    case ARES_ECANCELLED:
+      return absl::CancelledError(error_msg);
+    case ARES_ENOTIMP:
+      return absl::UnimplementedError(error_msg);
+    case ARES_ENOTFOUND:
+      return absl::NotFoundError(error_msg);
+    default:
+      return absl::UnknownError(error_msg);
+  }
+}
+
+// An alternative here could be to use ares_timeout to try to be more
+// accurate, but that would require using "struct timeval"'s, which just
+// makes things a bit more complicated. So just poll every second, as
+// suggested by the c-ares code comments.
+constexpr EventEngine::Duration kAresBackupPollAlarmDuration =
+    std::chrono::seconds(1);
+
+bool IsIpv6LoopbackAvailable() {
+#ifdef GRPC_POSIX_SOCKET_ARES_EV_DRIVER
+  return PosixSocketWrapper::IsIpv6LoopbackAvailable();
+#elif defined(GRPC_WINDOWS_SOCKET_ARES_EV_DRIVER)
+  // TODO(yijiem): implement this for Windows
+  return true;
+#else
+#error "Unsupported platform"
+#endif
+}
+
+absl::Status SetRequestDNSServer(absl::string_view dns_server,
+                                 ares_channel* channel) {
+  GRPC_ARES_RESOLVER_TRACE_LOG("Using DNS server %s", dns_server.data());
+  grpc_resolved_address addr;
+  struct ares_addr_port_node dns_server_addr = {};
+  if (grpc_parse_ipv4_hostport(dns_server, &addr, /*log_errors=*/false)) {
+    dns_server_addr.family = AF_INET;
+    struct sockaddr_in* in = reinterpret_cast<struct sockaddr_in*>(addr.addr);
+    memcpy(&dns_server_addr.addr.addr4, &in->sin_addr, sizeof(struct in_addr));
+    dns_server_addr.tcp_port = grpc_sockaddr_get_port(&addr);
+    dns_server_addr.udp_port = grpc_sockaddr_get_port(&addr);
+  } else if (grpc_parse_ipv6_hostport(dns_server, &addr,
+                                      /*log_errors=*/false)) {
+    dns_server_addr.family = AF_INET6;
+    struct sockaddr_in6* in6 =
+        reinterpret_cast<struct sockaddr_in6*>(addr.addr);
+    memcpy(&dns_server_addr.addr.addr6, &in6->sin6_addr,
+           sizeof(struct in6_addr));
+    dns_server_addr.tcp_port = grpc_sockaddr_get_port(&addr);
+    dns_server_addr.udp_port = grpc_sockaddr_get_port(&addr);
+  } else {
+    return absl::InvalidArgumentError(
+        absl::StrCat("Cannot parse authority: ", dns_server));
+  }
+  int status = ares_set_servers_ports(*channel, &dns_server_addr);
+  if (status != ARES_SUCCESS) {
+    return AresStatusToAbslStatus(status, ares_strerror(status));
+  }
+  return absl::OkStatus();
+}
+
+struct QueryArg {
+  QueryArg(AresResolver* ar, int id, absl::string_view name)
+      : ares_resolver(ar), callback_map_id(id), query_name(name) {}
+  AresResolver* ares_resolver;
+  int callback_map_id;
+  std::string query_name;
+};
+
+struct HostnameQueryArg : public QueryArg {
+  HostnameQueryArg(AresResolver* ar, int id, absl::string_view name, int p)
+      : QueryArg(ar, id, name), port(p) {}
+  int port;
+};
+
+}  // namespace
+
+absl::StatusOr<grpc_core::OrphanablePtr<AresResolver>>
+AresResolver::CreateAresResolver(
+    absl::string_view dns_server,
+    std::unique_ptr<GrpcPolledFdFactory> polled_fd_factory,
+    std::shared_ptr<EventEngine> event_engine) {
+  ares_options opts = {};
+  opts.flags |= ARES_FLAG_STAYOPEN;
+  ares_channel channel;
+  int status = ares_init_options(&channel, &opts, ARES_OPT_FLAGS);
+  if (status != ARES_SUCCESS) {
+    gpr_log(GPR_ERROR, "ares_init_options failed, status: %d", status);
+    return AresStatusToAbslStatus(
+        status,
+        absl::StrCat("Failed to init c-ares channel: ", ares_strerror(status)));
+  }
+  event_engine_grpc_ares_test_only_inject_config(&channel);
+  if (!dns_server.empty()) {
+    absl::Status status = SetRequestDNSServer(dns_server, &channel);
+    if (!status.ok()) {
+      return status;
+    }
+  }
+  return grpc_core::MakeOrphanable<AresResolver>(
+      std::move(polled_fd_factory), std::move(event_engine), channel);
+}
+
+AresResolver::~AresResolver() {
+  GPR_ASSERT(fd_node_list_.empty());
+  GPR_ASSERT(callback_map_.empty());
+  ares_destroy(channel_);
+}
+
+void AresResolver::Orphan() {
+  {
+    grpc_core::MutexLock lock(&mutex_);
+    shutting_down_ = true;
+    if (ares_backup_poll_alarm_handle_.has_value()) {
+      event_engine_->Cancel(*ares_backup_poll_alarm_handle_);
+      ares_backup_poll_alarm_handle_.reset();
+    }
+    for (const auto& fd_node : fd_node_list_) {
+      if (!fd_node->already_shutdown) {
+        GRPC_ARES_RESOLVER_TRACE_LOG("request: %p shutdown fd: %s", this,
+                                     fd_node->polled_fd->GetName());
+        fd_node->polled_fd->ShutdownLocked(
+            absl::CancelledError("AresResolver::Orphan"));
+        fd_node->already_shutdown = true;
+      }
+    }
+  }
+  Unref(DEBUG_LOCATION, "Orphan");
+}
+
+void AresResolver::LookupHostname(
+    absl::string_view name, absl::string_view default_port,
+    EventEngine::DNSResolver::LookupHostnameCallback callback) {
+  absl::string_view host;
+  absl::string_view port_string;
+  if (!grpc_core::SplitHostPort(name, &host, &port_string)) {
+    event_engine_->Run(
+        [callback = std::move(callback),
+         status = absl::InvalidArgumentError(absl::StrCat(
+             "Unparseable name: ", name))]() mutable { callback(status); });
+    return;
+  }
+  GPR_ASSERT(!host.empty());
+  if (port_string.empty()) {
+    if (default_port.empty()) {
+      event_engine_->Run([callback = std::move(callback),
+                          status = absl::InvalidArgumentError(absl::StrFormat(
+                              "No port in name %s or default_port argument",
+                              name))]() mutable { callback(status); });
+      return;
+    }
+    port_string = default_port;
+  }
+  int port = 0;
+  if (port_string == "http") {
+    port = 80;
+  } else if (port_string == "https") {
+    port = 443;
+  } else if (!absl::SimpleAtoi(port_string, &port)) {
+    event_engine_->Run([callback = std::move(callback),
+                        status = absl::InvalidArgumentError(absl::StrCat(
+                            "Failed to parse port in name: ",
+                            name))]() mutable { callback(status); });
+    return;
+  }
+  // TODO(yijiem): Change this when refactoring code in
+  // src/core/lib/address_utils to use EventEngine::ResolvedAddress.
+  grpc_resolved_address addr;
+  const std::string hostport = grpc_core::JoinHostPort(host, port);
+  if (grpc_parse_ipv4_hostport(hostport.c_str(), &addr,
+                               false /* log errors */) ||
+      grpc_parse_ipv6_hostport(hostport.c_str(), &addr,
+                               false /* log errors */)) {
+    // Early out if the target is an ipv4 or ipv6 literal.
+    std::vector<EventEngine::ResolvedAddress> result;
+    result.emplace_back(reinterpret_cast<sockaddr*>(addr.addr), addr.len);
+    event_engine_->Run(
+        [callback = std::move(callback), result = std::move(result)]() mutable {
+          callback(std::move(result));
+        });
+    return;
+  }
+  grpc_core::MutexLock lock(&mutex_);
+  callback_map_.emplace(++id_, std::move(callback));
+  auto* resolver_arg = new HostnameQueryArg(this, id_, name, port);
+  if (IsIpv6LoopbackAvailable()) {
+    ares_gethostbyname(channel_, std::string(host).c_str(), AF_UNSPEC,
+                       &AresResolver::OnHostbynameDoneLocked, resolver_arg);
+  } else {
+    ares_gethostbyname(channel_, std::string(host).c_str(), AF_INET,
+                       &AresResolver::OnHostbynameDoneLocked, resolver_arg);
+  }
+  CheckSocketsLocked();
+  MaybeStartTimerLocked();
+}
+
+void AresResolver::LookupSRV(
+    absl::string_view name,
+    EventEngine::DNSResolver::LookupSRVCallback callback) {
+  absl::string_view host;
+  absl::string_view port;
+  if (!grpc_core::SplitHostPort(name, &host, &port)) {
+    event_engine_->Run(
+        [callback = std::move(callback),
+         status = absl::InvalidArgumentError(absl::StrCat(
+             "Unparseable name: ", name))]() mutable { callback(status); });
+    return;
+  }
+  GPR_ASSERT(!host.empty());
+  // Don't query for SRV records if the target is "localhost"
+  if (absl::EqualsIgnoreCase(host, "localhost")) {
+    event_engine_->Run([callback = std::move(callback)]() mutable {
+      callback(std::vector<EventEngine::DNSResolver::SRVRecord>());
+    });
+    return;
+  }
+  grpc_core::MutexLock lock(&mutex_);
+  callback_map_.emplace(++id_, std::move(callback));
+  auto* resolver_arg = new QueryArg(this, id_, host);
+  ares_query(channel_, std::string(host).c_str(), ns_c_in, ns_t_srv,
+             &AresResolver::OnSRVQueryDoneLocked, resolver_arg);
+  CheckSocketsLocked();
+  MaybeStartTimerLocked();
+}
+
+void AresResolver::LookupTXT(
+    absl::string_view name,
+    EventEngine::DNSResolver::LookupTXTCallback callback) {
+  absl::string_view host;
+  absl::string_view port;
+  if (!grpc_core::SplitHostPort(name, &host, &port)) {
+    event_engine_->Run(
+        [callback = std::move(callback),
+         status = absl::InvalidArgumentError(absl::StrCat(
+             "Unparseable name: ", name))]() mutable { callback(status); });
+    return;
+  }
+  GPR_ASSERT(!host.empty());
+  // Don't query for TXT records if the target is "localhost"
+  if (absl::EqualsIgnoreCase(host, "localhost")) {
+    event_engine_->Run([callback = std::move(callback)]() mutable {
+      callback(std::vector<std::string>());
+    });
+    return;
+  }
+  grpc_core::MutexLock lock(&mutex_);
+  callback_map_.emplace(++id_, std::move(callback));
+  auto* resolver_arg = new QueryArg(this, id_, host);
+  ares_search(channel_, std::string(host).c_str(), ns_c_in, ns_t_txt,
+              &AresResolver::OnTXTDoneLocked, resolver_arg);
+  CheckSocketsLocked();
+  MaybeStartTimerLocked();
+}
+
+AresResolver::AresResolver(
+    std::unique_ptr<GrpcPolledFdFactory> polled_fd_factory,
+    std::shared_ptr<EventEngine> event_engine, ares_channel channel)
+    : grpc_core::InternallyRefCounted<AresResolver>(
+          GRPC_TRACE_FLAG_ENABLED(grpc_trace_ares_resolver) ? "AresResolver"
+                                                            : nullptr),
+      channel_(channel),
+      polled_fd_factory_(std::move(polled_fd_factory)),
+      event_engine_(std::move(event_engine)) {}
+
+void AresResolver::CheckSocketsLocked() {
+  FdNodeList new_list;
+  if (!shutting_down_) {
+    ares_socket_t socks[ARES_GETSOCK_MAXNUM];
+    int socks_bitmask = ares_getsock(channel_, socks, ARES_GETSOCK_MAXNUM);
+    for (size_t i = 0; i < ARES_GETSOCK_MAXNUM; i++) {
+      if (ARES_GETSOCK_READABLE(socks_bitmask, i) ||
+          ARES_GETSOCK_WRITABLE(socks_bitmask, i)) {
+        auto iter = std::find_if(
+            fd_node_list_.begin(), fd_node_list_.end(),
+            [sock = socks[i]](const auto& node) { return node->as == sock; });
+        if (iter == fd_node_list_.end()) {
+          new_list.push_back(std::make_unique<FdNode>(
+              socks[i], polled_fd_factory_->NewGrpcPolledFdLocked(socks[i])));
+          GRPC_ARES_RESOLVER_TRACE_LOG("request:%p new fd: %d", this, socks[i]);
+        } else {
+          new_list.splice(new_list.end(), fd_node_list_, iter);
+        }
+        FdNode* fd_node = new_list.back().get();
+        if (ARES_GETSOCK_READABLE(socks_bitmask, i) &&
+            !fd_node->readable_registered) {
+          fd_node->readable_registered = true;
+          if (fd_node->polled_fd->IsFdStillReadableLocked()) {
+            // If c-ares is interested to read and the socket already has data
+            // available for read, schedules OnReadable directly here. This is
+            // to cope with the edge-triggered poller not getting an event if no
+            // new data arrives and c-ares hasn't read all the data in the
+            // previous ares_process_fd.
+            GRPC_ARES_RESOLVER_TRACE_LOG(
+                "request:%p schedule read directly on: %d", this, fd_node->as);
+            event_engine_->Run(
+                [self = Ref(DEBUG_LOCATION, "CheckSocketsLocked"),
+                 fd_node]() mutable {
+                  self->OnReadable(fd_node, absl::OkStatus());
+                });
+          } else {
+            // Otherwise register with the poller for readable event.
+            GRPC_ARES_RESOLVER_TRACE_LOG("request:%p notify read on: %d", this,
+                                         fd_node->as);
+            fd_node->polled_fd->RegisterForOnReadableLocked(
+                [self = Ref(DEBUG_LOCATION, "CheckSocketsLocked"),
+                 fd_node](absl::Status status) mutable {
+                  self->OnReadable(fd_node, status);
+                });
+          }
+        }
+        // Register write_closure if the socket is writable and write_closure
+        // has not been registered with this socket.
+        if (ARES_GETSOCK_WRITABLE(socks_bitmask, i) &&
+            !fd_node->writable_registered) {
+          GRPC_ARES_RESOLVER_TRACE_LOG("request:%p notify write on: %d", this,
+                                       fd_node->as);
+          fd_node->writable_registered = true;
+          fd_node->polled_fd->RegisterForOnWriteableLocked(
+              [self = Ref(DEBUG_LOCATION, "CheckSocketsLocked"),
+               fd_node](absl::Status status) mutable {
+                self->OnWritable(fd_node, status);
+              });
+        }
+      }
+    }
+  }
+  // Any remaining fds in fd_node_list_ were not returned by ares_getsock()
+  // and are therefore no longer in use, so they can be shut down and removed
+  // from the list.
+  while (!fd_node_list_.empty()) {
+    FdNode* fd_node = fd_node_list_.front().get();
+    if (!fd_node->already_shutdown) {
+      GRPC_ARES_RESOLVER_TRACE_LOG("request: %p shutdown fd: %s", this,
+                                   fd_node->polled_fd->GetName());
+      fd_node->polled_fd->ShutdownLocked(absl::OkStatus());
+      fd_node->already_shutdown = true;
+    }
+    if (!fd_node->readable_registered && !fd_node->writable_registered) {
+      GRPC_ARES_RESOLVER_TRACE_LOG("request: %p delete fd: %s", this,
+                                   fd_node->polled_fd->GetName());
+      fd_node_list_.pop_front();
+    } else {
+      new_list.splice(new_list.end(), fd_node_list_, fd_node_list_.begin());
+    }
+  }
+  fd_node_list_ = std::move(new_list);
+}
+
+void AresResolver::MaybeStartTimerLocked() {
+  if (ares_backup_poll_alarm_handle_.has_value()) {
+    return;
+  }
+  // Initialize the backup poll alarm
+  GRPC_ARES_RESOLVER_TRACE_LOG(
+      "request:%p MaybeStartTimerLocked next ares process poll time in %zu ms",
+      this, Milliseconds(kAresBackupPollAlarmDuration));
+  ares_backup_poll_alarm_handle_ = event_engine_->RunAfter(
+      kAresBackupPollAlarmDuration,
+      [self = Ref(DEBUG_LOCATION, "MaybeStartTimerLocked")]() {
+        self->OnAresBackupPollAlarm();
+      });
+}
+
+void AresResolver::OnReadable(FdNode* fd_node, absl::Status status) {
+  grpc_core::MutexLock lock(&mutex_);
+  GPR_ASSERT(fd_node->readable_registered);
+  fd_node->readable_registered = false;
+  GRPC_ARES_RESOLVER_TRACE_LOG("OnReadable: fd: %d; request: %p; status: %s",
+                               fd_node->as, this, status.ToString().c_str());
+  if (status.ok() && !shutting_down_) {
+    ares_process_fd(channel_, fd_node->as, ARES_SOCKET_BAD);
+  } else {
+    // If error is not absl::OkStatus() or the resolution was cancelled, it
+    // means the fd has been shutdown or timed out. The pending lookups made
+    // on this request will be cancelled by the following ares_cancel(). The
+    // remaining file descriptors in this request will be cleaned up in the
+    // following Work() method.
+    ares_cancel(channel_);
+  }
+  CheckSocketsLocked();
+}
+
+void AresResolver::OnWritable(FdNode* fd_node, absl::Status status) {
+  grpc_core::MutexLock lock(&mutex_);
+  GPR_ASSERT(fd_node->writable_registered);
+  fd_node->writable_registered = false;
+  GRPC_ARES_RESOLVER_TRACE_LOG("OnWritable: fd: %d; request:%p; status: %s",
+                               fd_node->as, this, status.ToString().c_str());
+  if (status.ok() && !shutting_down_) {
+    ares_process_fd(channel_, ARES_SOCKET_BAD, fd_node->as);
+  } else {
+    // If error is not absl::OkStatus() or the resolution was cancelled, it
+    // means the fd has been shutdown or timed out. The pending lookups made
+    // on this request will be cancelled by the following ares_cancel(). The
+    // remaining file descriptors in this request will be cleaned up in the
+    // following Work() method.
+    ares_cancel(channel_);
+  }
+  CheckSocketsLocked();
+}
+
+// In case of non-responsive DNS servers, dropped packets, etc., c-ares has
+// intelligent timeout and retry logic, which we can take advantage of by
+// polling ares_process_fd on time intervals. Overall, the c-ares library is
+// meant to be called into and given a chance to proceed name resolution:
+//   a) when fd events happen
+//   b) when some time has passed without fd events having happened
+// For the latter, we use this backup poller. Also see
+// https://github.com/grpc/grpc/pull/17688 description for more details.
+void AresResolver::OnAresBackupPollAlarm() {
+  grpc_core::MutexLock lock(&mutex_);
+  ares_backup_poll_alarm_handle_.reset();
+  GRPC_ARES_RESOLVER_TRACE_LOG(
+      "request:%p OnAresBackupPollAlarm shutting_down=%d.", this,
+      shutting_down_);
+  if (!shutting_down_) {
+    for (const auto& fd_node : fd_node_list_) {
+      if (!fd_node->already_shutdown) {
+        GRPC_ARES_RESOLVER_TRACE_LOG(
+            "request:%p OnAresBackupPollAlarm; ares_process_fd. fd=%s", this,
+            fd_node->polled_fd->GetName());
+        ares_socket_t as = fd_node->polled_fd->GetWrappedAresSocketLocked();
+        ares_process_fd(channel_, as, as);
+      }
+    }
+    MaybeStartTimerLocked();
+    CheckSocketsLocked();
+  }
+}
+
+void AresResolver::OnHostbynameDoneLocked(void* arg, int status,
+                                          int /*timeouts*/,
+                                          struct hostent* hostent) {
+  std::unique_ptr<HostnameQueryArg> hostname_qa(
+      static_cast<HostnameQueryArg*>(arg));
+  auto* ares_resolver = hostname_qa->ares_resolver;
+  auto nh = ares_resolver->callback_map_.extract(hostname_qa->callback_map_id);
+  GPR_ASSERT(!nh.empty());
+  GPR_ASSERT(
+      absl::holds_alternative<EventEngine::DNSResolver::LookupHostnameCallback>(
+          nh.mapped()));
+  auto callback = absl::get<EventEngine::DNSResolver::LookupHostnameCallback>(
+      std::move(nh.mapped()));
+  if (status != ARES_SUCCESS) {
+    std::string error_msg =
+        absl::StrFormat("address lookup failed for %s: %s",
+                        hostname_qa->query_name, ares_strerror(status));
+    GRPC_ARES_RESOLVER_TRACE_LOG("resolver:%p OnHostbynameDoneLocked: %s",
+                                 ares_resolver, error_msg.c_str());
+    ares_resolver->event_engine_->Run(
+        [callback = std::move(callback),
+         status = AresStatusToAbslStatus(status, error_msg)]() mutable {
+          callback(status);
+        });
+    return;
+  }
+  GRPC_ARES_RESOLVER_TRACE_LOG(
+      "resolver:%p OnHostbynameDoneLocked name=%s ARES_SUCCESS", ares_resolver,
+      hostname_qa->query_name.c_str());
+  std::vector<EventEngine::ResolvedAddress> result;
+  for (size_t i = 0; hostent->h_addr_list[i] != nullptr; i++) {
+    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],
+               sizeof(struct in6_addr));
+        addr.sin6_family = static_cast<unsigned char>(hostent->h_addrtype);
+        addr.sin6_port = htons(hostname_qa->port);
+        result.emplace_back(reinterpret_cast<const sockaddr*>(&addr), addr_len);
+        char output[INET6_ADDRSTRLEN];
+        ares_inet_ntop(AF_INET6, &addr.sin6_addr, output, INET6_ADDRSTRLEN);
+        GRPC_ARES_RESOLVER_TRACE_LOG(
+            "resolver:%p c-ares resolver gets a AF_INET6 result: \n"
+            "  addr: %s\n  port: %d\n  sin6_scope_id: %d\n",
+            ares_resolver, output, hostname_qa->port, addr.sin6_scope_id);
+        break;
+      }
+      case AF_INET: {
+        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], sizeof(struct in_addr));
+        addr.sin_family = static_cast<unsigned char>(hostent->h_addrtype);
+        addr.sin_port = htons(hostname_qa->port);
+        result.emplace_back(reinterpret_cast<const sockaddr*>(&addr), addr_len);
+        char output[INET_ADDRSTRLEN];
+        ares_inet_ntop(AF_INET, &addr.sin_addr, output, INET_ADDRSTRLEN);
+        GRPC_ARES_RESOLVER_TRACE_LOG(
+            "resolver:%p c-ares resolver gets a AF_INET result: \n"
+            "  addr: %s\n  port: %d\n",
+            ares_resolver, output, hostname_qa->port);
+        break;
+      }
+    }
+  }
+  ares_resolver->event_engine_->Run(
+      [callback = std::move(callback), result = std::move(result)]() mutable {
+        callback(std::move(result));
+      });
+}
+
+void AresResolver::OnSRVQueryDoneLocked(void* arg, int status, int /*timeouts*/,
+                                        unsigned char* abuf, int alen) {
+  std::unique_ptr<QueryArg> qa(static_cast<QueryArg*>(arg));
+  auto* ares_resolver = qa->ares_resolver;
+  auto nh = ares_resolver->callback_map_.extract(qa->callback_map_id);
+  GPR_ASSERT(!nh.empty());
+  GPR_ASSERT(
+      absl::holds_alternative<EventEngine::DNSResolver::LookupSRVCallback>(
+          nh.mapped()));
+  auto callback = absl::get<EventEngine::DNSResolver::LookupSRVCallback>(
+      std::move(nh.mapped()));
+  auto fail = [&](absl::string_view prefix) {
+    std::string error_message = absl::StrFormat(
+        "%s for %s: %s", prefix, qa->query_name, ares_strerror(status));
+    GRPC_ARES_RESOLVER_TRACE_LOG("OnSRVQueryDoneLocked: %s",
+                                 error_message.c_str());
+    ares_resolver->event_engine_->Run(
+        [callback = std::move(callback),
+         status = AresStatusToAbslStatus(status, error_message)]() mutable {
+          callback(status);
+        });
+  };
+  if (status != ARES_SUCCESS) {
+    fail("SRV lookup failed");
+    return;
+  }
+  GRPC_ARES_RESOLVER_TRACE_LOG(
+      "resolver:%p OnSRVQueryDoneLocked name=%s ARES_SUCCESS", ares_resolver,
+      qa->query_name.c_str());
+  struct ares_srv_reply* reply = nullptr;
+  status = ares_parse_srv_reply(abuf, alen, &reply);
+  GRPC_ARES_RESOLVER_TRACE_LOG("resolver:%p ares_parse_srv_reply: %d",
+                               ares_resolver, status);
+  if (status != ARES_SUCCESS) {
+    fail("Failed to parse SRV reply");
+    return;
+  }
+  std::vector<EventEngine::DNSResolver::SRVRecord> result;
+  for (struct ares_srv_reply* srv_it = reply; srv_it != nullptr;
+       srv_it = srv_it->next) {
+    EventEngine::DNSResolver::SRVRecord record;
+    record.host = srv_it->host;
+    record.port = srv_it->port;
+    record.priority = srv_it->priority;
+    record.weight = srv_it->weight;
+    result.push_back(std::move(record));
+  }
+  if (reply != nullptr) {
+    ares_free_data(reply);
+  }
+  ares_resolver->event_engine_->Run(
+      [callback = std::move(callback), result = std::move(result)]() mutable {
+        callback(std::move(result));
+      });
+}
+
+void AresResolver::OnTXTDoneLocked(void* arg, int status, int /*timeouts*/,
+                                   unsigned char* buf, int len) {
+  std::unique_ptr<QueryArg> qa(static_cast<QueryArg*>(arg));
+  auto* ares_resolver = qa->ares_resolver;
+  auto nh = ares_resolver->callback_map_.extract(qa->callback_map_id);
+  GPR_ASSERT(!nh.empty());
+  GPR_ASSERT(
+      absl::holds_alternative<EventEngine::DNSResolver::LookupTXTCallback>(
+          nh.mapped()));
+  auto callback = absl::get<EventEngine::DNSResolver::LookupTXTCallback>(
+      std::move(nh.mapped()));
+  auto fail = [&](absl::string_view prefix) {
+    std::string error_message = absl::StrFormat(
+        "%s for %s: %s", prefix, qa->query_name, ares_strerror(status));
+    GRPC_ARES_RESOLVER_TRACE_LOG("resolver:%p OnTXTDoneLocked: %s",
+                                 ares_resolver, error_message.c_str());
+    ares_resolver->event_engine_->Run(
+        [callback = std::move(callback),
+         status = AresStatusToAbslStatus(status, error_message)]() mutable {
+          callback(status);
+        });
+  };
+  if (status != ARES_SUCCESS) {
+    fail("TXT lookup failed");
+    return;
+  }
+  GRPC_ARES_RESOLVER_TRACE_LOG(
+      "resolver:%p OnTXTDoneLocked name=%s ARES_SUCCESS", ares_resolver,
+      qa->query_name.c_str());
+  struct ares_txt_ext* reply = nullptr;
+  status = ares_parse_txt_reply_ext(buf, len, &reply);
+  if (status != ARES_SUCCESS) {
+    fail("Failed to parse TXT result");
+    return;
+  }
+  std::vector<std::string> result;
+  for (struct ares_txt_ext* part = reply; part != nullptr; part = part->next) {
+    if (part->record_start) {
+      result.emplace_back(reinterpret_cast<char*>(part->txt), part->length);
+    } else {
+      absl::StrAppend(
+          &result.back(),
+          std::string(reinterpret_cast<char*>(part->txt), part->length));
+    }
+  }
+  GRPC_ARES_RESOLVER_TRACE_LOG("resolver:%p Got %zu TXT records", ares_resolver,
+                               result.size());
+  if (GRPC_TRACE_FLAG_ENABLED(grpc_trace_ares_resolver)) {
+    for (const auto& record : result) {
+      gpr_log(GPR_INFO, "%s", record.c_str());
+    }
+  }
+  // Clean up.
+  ares_free_data(reply);
+  ares_resolver->event_engine_->Run(
+      [callback = std::move(callback), result = std::move(result)]() mutable {
+        callback(std::move(result));
+      });
+}
+
+}  // namespace experimental
+}  // namespace grpc_event_engine
+
+void noop_inject_channel_config(ares_channel* /*channel*/) {}
+
+void (*event_engine_grpc_ares_test_only_inject_config)(ares_channel* channel) =
+    noop_inject_channel_config;
+
+#endif  // GRPC_ARES == 1
--- a/src/core/lib/event_engine/ares_resolver.h
+++ b/src/core/lib/event_engine/ares_resolver.h
@ -0,0 +1,147 @@
+// Copyright 2023 The 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_SRC_CORE_LIB_EVENT_ENGINE_ARES_RESOLVER_H
+#define GRPC_SRC_CORE_LIB_EVENT_ENGINE_ARES_RESOLVER_H
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/debug/trace.h"
+
+#if GRPC_ARES == 1
+
+#include <list>
+#include <memory>
+
+#include <ares.h>
+
+#include "absl/base/thread_annotations.h"
+#include "absl/container/flat_hash_map.h"
+#include "absl/status/status.h"
+#include "absl/status/statusor.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "absl/types/variant.h"
+
+#include <grpc/event_engine/event_engine.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/event_engine/grpc_polled_fd.h"
+#include "src/core/lib/gprpp/orphanable.h"
+#include "src/core/lib/gprpp/sync.h"
+
+namespace grpc_event_engine {
+namespace experimental {
+
+extern grpc_core::TraceFlag grpc_trace_ares_resolver;
+
+#define GRPC_ARES_RESOLVER_TRACE_LOG(format, ...)                              \
+  do {                                                                         \
+    if (GRPC_TRACE_FLAG_ENABLED(grpc_trace_ares_resolver)) {                   \
+      gpr_log(GPR_INFO, "(EventEngine c-ares resolver) " format, __VA_ARGS__); \
+    }                                                                          \
+  } while (0)
+
+class AresResolver : public grpc_core::InternallyRefCounted<AresResolver> {
+ public:
+  static absl::StatusOr<grpc_core::OrphanablePtr<AresResolver>>
+  CreateAresResolver(absl::string_view dns_server,
+                     std::unique_ptr<GrpcPolledFdFactory> polled_fd_factory,
+                     std::shared_ptr<EventEngine> event_engine);
+
+  // Do not instantiate directly -- use CreateAresResolver() instead.
+  AresResolver(std::unique_ptr<GrpcPolledFdFactory> polled_fd_factory,
+               std::shared_ptr<EventEngine> event_engine, ares_channel channel);
+  ~AresResolver() override;
+  void Orphan() override ABSL_LOCKS_EXCLUDED(mutex_);
+
+  void LookupHostname(absl::string_view name, absl::string_view default_port,
+                      EventEngine::DNSResolver::LookupHostnameCallback callback)
+      ABSL_LOCKS_EXCLUDED(mutex_);
+  void LookupSRV(absl::string_view name,
+                 EventEngine::DNSResolver::LookupSRVCallback callback)
+      ABSL_LOCKS_EXCLUDED(mutex_);
+  void LookupTXT(absl::string_view name,
+                 EventEngine::DNSResolver::LookupTXTCallback callback)
+      ABSL_LOCKS_EXCLUDED(mutex_);
+
+ private:
+  // A FdNode saves (not owns) a live socket/fd which c-ares creates, and owns a
+  // GrpcPolledFd object which has a platform-agnostic interface to interact
+  // with the poller. The liveness of the socket means that c-ares needs us to
+  // monitor r/w events on this socket and notifies c-ares when such events have
+  // happened which we achieve through the GrpcPolledFd object. FdNode also
+  // handles the shutdown (maybe due to socket no longer used, finished request,
+  // cancel or timeout) and the destruction of the poller handle. Note that
+  // FdNode does not own the socket and it's the c-ares' responsibility to
+  // close the socket (possibly through ares_destroy).
+  struct FdNode {
+    FdNode() = default;
+    FdNode(ares_socket_t as, GrpcPolledFd* polled_fd)
+        : as(as), polled_fd(polled_fd) {}
+    ares_socket_t as;
+    std::unique_ptr<GrpcPolledFd> polled_fd;
+    // true if the readable closure has been registered
+    bool readable_registered = false;
+    // true if the writable closure has been registered
+    bool writable_registered = false;
+    bool already_shutdown = false;
+  };
+  using FdNodeList = std::list<std::unique_ptr<FdNode>>;
+
+  using CallbackType =
+      absl::variant<EventEngine::DNSResolver::LookupHostnameCallback,
+                    EventEngine::DNSResolver::LookupSRVCallback,
+                    EventEngine::DNSResolver::LookupTXTCallback>;
+
+  void CheckSocketsLocked() ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  void MaybeStartTimerLocked() ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+  void OnReadable(FdNode* fd_node, absl::Status status)
+      ABSL_LOCKS_EXCLUDED(mutex_);
+  void OnWritable(FdNode* fd_node, absl::Status status)
+      ABSL_LOCKS_EXCLUDED(mutex_);
+  void OnAresBackupPollAlarm() ABSL_LOCKS_EXCLUDED(mutex_);
+
+  // These callbacks are invoked from the c-ares library, so disable thread
+  // safety analysis. We are guaranteed to be holding mutex_.
+  static void OnHostbynameDoneLocked(void* arg, int status, int /*timeouts*/,
+                                     struct hostent* hostent)
+      ABSL_NO_THREAD_SAFETY_ANALYSIS;
+  static void OnSRVQueryDoneLocked(void* arg, int status, int /*timeouts*/,
+                                   unsigned char* abuf,
+                                   int alen) ABSL_NO_THREAD_SAFETY_ANALYSIS;
+  static void OnTXTDoneLocked(void* arg, int status, int /*timeouts*/,
+                              unsigned char* buf,
+                              int len) ABSL_NO_THREAD_SAFETY_ANALYSIS;
+
+  grpc_core::Mutex mutex_;
+  bool shutting_down_ ABSL_GUARDED_BY(mutex_) = false;
+  ares_channel channel_ ABSL_GUARDED_BY(mutex_);
+  FdNodeList fd_node_list_ ABSL_GUARDED_BY(mutex_);
+  int id_ ABSL_GUARDED_BY(mutex_) = 0;
+  absl::flat_hash_map<int, CallbackType> callback_map_ ABSL_GUARDED_BY(mutex_);
+  absl::optional<EventEngine::TaskHandle> ares_backup_poll_alarm_handle_
+      ABSL_GUARDED_BY(mutex_);
+  std::unique_ptr<GrpcPolledFdFactory> polled_fd_factory_;
+  std::shared_ptr<EventEngine> event_engine_;
+};
+
+}  // namespace experimental
+}  // namespace grpc_event_engine
+
+// Exposed in this header for C-core tests only
+extern void (*event_engine_grpc_ares_test_only_inject_config)(
+    ares_channel* channel);
+
+#endif  // GRPC_ARES == 1
+#endif  // GRPC_SRC_CORE_LIB_EVENT_ENGINE_ARES_RESOLVER_H
--- a/src/core/lib/event_engine/grpc_polled_fd.h
+++ b/src/core/lib/event_engine/grpc_polled_fd.h
@ -0,0 +1,73 @@
+// Copyright 2023 The 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_SRC_CORE_LIB_EVENT_ENGINE_GRPC_POLLED_FD_H
+#define GRPC_SRC_CORE_LIB_EVENT_ENGINE_GRPC_POLLED_FD_H
+
+#include <grpc/support/port_platform.h>
+
+#if GRPC_ARES == 1
+
+#include <ares.h>
+
+#include "absl/functional/any_invocable.h"
+#include "absl/status/status.h"
+
+#include "src/core/lib/iomgr/error.h"
+
+namespace grpc_event_engine {
+namespace experimental {
+
+// A wrapped fd that integrates with the EventEngine poller of the current
+// platform. A GrpcPolledFd knows how to create grpc platform-specific poller
+// handle from "ares_socket_t" sockets, and then sign up for
+// readability/writeability with that poller handle, and do shutdown and
+// destruction.
+class GrpcPolledFd {
+ public:
+  virtual ~GrpcPolledFd() {}
+  // Called when c-ares library is interested and there's no pending callback
+  virtual void RegisterForOnReadableLocked(
+      absl::AnyInvocable<void(absl::Status)> read_closure) = 0;
+  // Called when c-ares library is interested and there's no pending callback
+  virtual void RegisterForOnWriteableLocked(
+      absl::AnyInvocable<void(absl::Status)> write_closure) = 0;
+  // Indicates if there is data left even after just being read from
+  virtual bool IsFdStillReadableLocked() = 0;
+  // Called once and only once. Must cause cancellation of any pending
+  // read/write callbacks.
+  virtual void ShutdownLocked(grpc_error_handle error) = 0;
+  // Get the underlying ares_socket_t that this was created from
+  virtual ares_socket_t GetWrappedAresSocketLocked() = 0;
+  // A unique name, for logging
+  virtual const char* GetName() const = 0;
+};
+
+// A GrpcPolledFdFactory is 1-to-1 with and owned by a GrpcAresRequest. It knows
+// how to create GrpcPolledFd's for the current platform, and the
+// GrpcAresRequest uses it for all of its fd's.
+class GrpcPolledFdFactory {
+ public:
+  virtual ~GrpcPolledFdFactory() {}
+  // Creates a new wrapped fd for the current platform
+  virtual GrpcPolledFd* NewGrpcPolledFdLocked(ares_socket_t as) = 0;
+  // Optionally configures the ares channel after creation
+  virtual void ConfigureAresChannelLocked(ares_channel channel) = 0;
+};
+
+}  // namespace experimental
+}  // namespace grpc_event_engine
+
+#endif  // GRPC_ARES == 1
+#endif  // GRPC_SRC_CORE_LIB_EVENT_ENGINE_GRPC_POLLED_FD_H
--- a/src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h
+++ b/src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h
@ -0,0 +1,112 @@
+// Copyright 2023 The 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_SRC_CORE_LIB_EVENT_ENGINE_POSIX_ENGINE_GRPC_POLLED_FD_POSIX_H
+#define GRPC_SRC_CORE_LIB_EVENT_ENGINE_POSIX_ENGINE_GRPC_POLLED_FD_POSIX_H
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/iomgr/port.h"
+
+#if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER)
+
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include <string>
+#include <utility>
+
+#include <ares.h>
+
+#include "absl/functional/any_invocable.h"
+#include "absl/status/status.h"
+#include "absl/strings/str_cat.h"
+
+#include "src/core/lib/event_engine/grpc_polled_fd.h"
+#include "src/core/lib/event_engine/posix_engine/event_poller.h"
+#include "src/core/lib/event_engine/posix_engine/posix_engine_closure.h"
+#include "src/core/lib/iomgr/error.h"
+
+namespace grpc_event_engine {
+namespace experimental {
+
+class GrpcPolledFdPosix : public GrpcPolledFd {
+ public:
+  GrpcPolledFdPosix(ares_socket_t as, EventHandle* handle)
+      : name_(absl::StrCat("c-ares fd: ", static_cast<int>(as))),
+        as_(as),
+        handle_(handle) {}
+
+  ~GrpcPolledFdPosix() override {
+    // c-ares library will close the fd. This fd may be picked up immediately by
+    // another thread and should not be closed by the following OrphanHandle.
+    int phony_release_fd;
+    handle_->OrphanHandle(/*on_done=*/nullptr, &phony_release_fd,
+                          "c-ares query finished");
+  }
+
+  void RegisterForOnReadableLocked(
+      absl::AnyInvocable<void(absl::Status)> read_closure) override {
+    handle_->NotifyOnRead(new PosixEngineClosure(std::move(read_closure),
+                                                 /*is_permanent=*/false));
+  }
+
+  void RegisterForOnWriteableLocked(
+      absl::AnyInvocable<void(absl::Status)> write_closure) override {
+    handle_->NotifyOnWrite(new PosixEngineClosure(std::move(write_closure),
+                                                  /*is_permanent=*/false));
+  }
+
+  bool IsFdStillReadableLocked() override {
+    size_t bytes_available = 0;
+    return ioctl(handle_->WrappedFd(), FIONREAD, &bytes_available) == 0 &&
+           bytes_available > 0;
+  }
+
+  void ShutdownLocked(grpc_error_handle error) override {
+    handle_->ShutdownHandle(error);
+  }
+
+  ares_socket_t GetWrappedAresSocketLocked() override { return as_; }
+
+  const char* GetName() const override { return name_.c_str(); }
+
+ private:
+  const std::string name_;
+  const ares_socket_t as_;
+  EventHandle* handle_;
+};
+
+class GrpcPolledFdFactoryPosix : public GrpcPolledFdFactory {
+ public:
+  explicit GrpcPolledFdFactoryPosix(PosixEventPoller* poller)
+      : poller_(poller) {}
+
+  GrpcPolledFd* NewGrpcPolledFdLocked(ares_socket_t as) override {
+    return new GrpcPolledFdPosix(
+        as,
+        poller_->CreateHandle(as, "c-ares socket", poller_->CanTrackErrors()));
+  }
+
+  void ConfigureAresChannelLocked(ares_channel /*channel*/) override {}
+
+ private:
+  PosixEventPoller* poller_;
+};
+
+}  // namespace experimental
+}  // namespace grpc_event_engine
+
+#endif  // GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER)
+#endif  // GRPC_SRC_CORE_LIB_EVENT_ENGINE_POSIX_ENGINE_GRPC_POLLED_FD_POSIX_H
--- a/src/core/lib/event_engine/posix_engine/posix_engine.cc
+++ b/src/core/lib/event_engine/posix_engine/posix_engine.cc
@ -18,6 +18,7 @@
 #include <algorithm>
 #include <atomic>
 #include <chrono>
+#include <cstdint>
 #include <cstring>
 #include <memory>
 #include <string>
@ -37,8 +38,10 @@
 #include <grpc/support/log.h>

 #include "src/core/lib/debug/trace.h"
+#include "src/core/lib/event_engine/grpc_polled_fd.h"
 #include "src/core/lib/event_engine/poller.h"
 #include "src/core/lib/event_engine/posix.h"
+#include "src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h"
 #include "src/core/lib/event_engine/posix_engine/tcp_socket_utils.h"
 #include "src/core/lib/event_engine/posix_engine/timer.h"
 #include "src/core/lib/event_engine/tcp_socket_utils.h"
@ -487,10 +490,49 @@ EventEngine::TaskHandle PosixEventEngine::RunAfterInternal(
  return handle;
 }

+#if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_TCP)
+
+PosixEventEngine::PosixDNSResolver::PosixDNSResolver(
+    grpc_core::OrphanablePtr<AresResolver> ares_resolver)
+    : ares_resolver_(std::move(ares_resolver)) {}
+
+void PosixEventEngine::PosixDNSResolver::LookupHostname(
+    LookupHostnameCallback on_resolve, absl::string_view name,
+    absl::string_view default_port) {
+  ares_resolver_->LookupHostname(name, default_port, std::move(on_resolve));
+}
+
+void PosixEventEngine::PosixDNSResolver::LookupSRV(LookupSRVCallback on_resolve,
+                                                   absl::string_view name) {
+  ares_resolver_->LookupSRV(name, std::move(on_resolve));
+}
+
+void PosixEventEngine::PosixDNSResolver::LookupTXT(LookupTXTCallback on_resolve,
+                                                   absl::string_view name) {
+  ares_resolver_->LookupTXT(name, std::move(on_resolve));
+}
+
+#endif  // GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_TCP)
+
 absl::StatusOr<std::unique_ptr<EventEngine::DNSResolver>>
 PosixEventEngine::GetDNSResolver(
-    EventEngine::DNSResolver::ResolverOptions const& /*options*/) {
+    const EventEngine::DNSResolver::ResolverOptions& options) {
+#if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_TCP)
+  auto ares_resolver = AresResolver::CreateAresResolver(
+      options.dns_server,
+      std::make_unique<GrpcPolledFdFactoryPosix>(poller_manager_->Poller()),
+      shared_from_this());
+  if (!ares_resolver.ok()) {
+    return ares_resolver.status();
+  }
+  return std::make_unique<PosixEventEngine::PosixDNSResolver>(
+      std::move(*ares_resolver));
+#else   // GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_TCP)
+  // TODO(yijiem): Implement a basic A/AAAA-only native resolver in
+  // PosixEventEngine.
+  (void)options;
  grpc_core::Crash("unimplemented");
+#endif  // GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_TCP)
 }

 bool PosixEventEngine::IsWorkerThread() { grpc_core::Crash("unimplemented"); }
--- a/src/core/lib/event_engine/posix_engine/posix_engine.h
+++ b/src/core/lib/event_engine/posix_engine/posix_engine.h
@ -34,11 +34,13 @@
 #include <grpc/event_engine/event_engine.h>
 #include <grpc/event_engine/memory_allocator.h>

+#include "src/core/lib/event_engine/ares_resolver.h"
 #include "src/core/lib/event_engine/handle_containers.h"
 #include "src/core/lib/event_engine/posix.h"
 #include "src/core/lib/event_engine/posix_engine/event_poller.h"
 #include "src/core/lib/event_engine/posix_engine/timer_manager.h"
 #include "src/core/lib/event_engine/thread_pool/thread_pool.h"
+#include "src/core/lib/gprpp/orphanable.h"
 #include "src/core/lib/gprpp/sync.h"
 #include "src/core/lib/iomgr/port.h"
 #include "src/core/lib/surface/init_internally.h"
@ -138,7 +140,11 @@ class PosixEventEngine final : public PosixEventEngineWithFdSupport,
 public:
  class PosixDNSResolver : public EventEngine::DNSResolver {
   public:
-    ~PosixDNSResolver() override;
+    PosixDNSResolver() = delete;
+#if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_TCP)
+    explicit PosixDNSResolver(
+        grpc_core::OrphanablePtr<AresResolver> ares_resolver);
+#endif  // GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_TCP)
    void LookupHostname(LookupHostnameCallback on_resolve,
                        absl::string_view name,
                        absl::string_view default_port) override;
@ -146,6 +152,11 @@ class PosixEventEngine final : public PosixEventEngineWithFdSupport,
                   absl::string_view name) override;
    void LookupTXT(LookupTXTCallback on_resolve,
                   absl::string_view name) override;
+
+#if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_TCP)
+   private:
+    grpc_core::OrphanablePtr<AresResolver> ares_resolver_;
+#endif  // GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_TCP)
  };

 #ifdef GRPC_POSIX_SOCKET_TCP
--- a/src/core/lib/experiments/experiments.yaml
+++ b/src/core/lib/experiments/experiments.yaml
@ -119,7 +119,7 @@
    If set, use EventEngine DNSResolver for client channel resolution
  expiry: 2023/10/01
  owner: yijiem@google.com
-  test_tags: []
+  test_tags: ["cancel_ares_query_test", "resolver_component_tests_runner_invoker"]
  allow_in_fuzzing_config: false
 - name: work_stealing
  description:
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@ -491,6 +491,7 @@ CORE_SOURCE_FILES = [
    'src/core/lib/debug/stats.cc',
    'src/core/lib/debug/stats_data.cc',
    'src/core/lib/debug/trace.cc',
+    'src/core/lib/event_engine/ares_resolver.cc',
    'src/core/lib/event_engine/cf_engine/cf_engine.cc',
    'src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc',
    'src/core/lib/event_engine/channel_args_endpoint_config.cc',
--- a/templates/CMakeLists.txt.template
+++ b/templates/CMakeLists.txt.template
@ -82,7 +82,11 @@
      deps.append("${_gRPC_ADDRESS_SORTING_LIBRARIES}")
      deps.append("${_gRPC_RE2_LIBRARIES}")
      deps.append("${_gRPC_UPB_LIBRARIES}")
+    # TODO(yijiem): These targets depend on grpc_base instead of grpc. Since we don't populate grpc_base as a cmake target, the sources all get collapsed into these targets. This workaround adds c-ares and/or re2 dependencies to these targets. We should clean this up.
+    if target_dict['name'] in ['frame_test']:
+      deps.append("${_gRPC_CARES_LIBRARIES}")
    if target_dict['name'] in ['grpc_authorization_provider']:
+      deps.append("${_gRPC_CARES_LIBRARIES}")
      deps.append("${_gRPC_RE2_LIBRARIES}")
    deps.append("${_gRPC_ALLTARGETS_LIBRARIES}")
    for d in target_dict.get('deps', []):
--- a/templates/test/cpp/naming/resolver_component_tests_defs.include
+++ b/templates/test/cpp/naming/resolver_component_tests_defs.include
@ -1,4 +1,4 @@
-<%def name="resolver_component_tests(tests)">#!/usr/bin/env python
+<%def name="resolver_component_tests(tests)">#!/usr/bin/env python3
 # Copyright 2015 gRPC authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@ -58,6 +58,9 @@ if cur_resolver and cur_resolver != 'ares':
  test_runner_log('Exit 1 without running tests.')
  sys.exit(1)
 os.environ.update({'GRPC_TRACE': 'cares_resolver,cares_address_sorting'})
+experiments = os.environ.get('GRPC_EXPERIMENTS')
+if experiments is not None and 'event_engine_dns' in experiments:
+  os.environ.update({'GRPC_TRACE': 'event_engine_client_channel_resolver,cares_resolver'})

 def wait_until_dns_server_is_up(args,
                                dns_server_subprocess,
--- a/test/core/event_engine/test_suite/BUILD
+++ b/test/core/event_engine/test_suite/BUILD
@ -50,6 +50,7 @@ grpc_cc_test(
        "//test/core/event_engine:event_engine_test_utils",
        "//test/core/event_engine/test_suite/posix:oracle_event_engine_posix",
        "//test/core/event_engine/test_suite/tests:client",
+        "//test/core/event_engine/test_suite/tests:dns",
        "//test/core/event_engine/test_suite/tests:server",
        "//test/core/event_engine/test_suite/tests:timer",
    ],
--- a/test/core/event_engine/test_suite/tests/BUILD
+++ b/test/core/event_engine/test_suite/tests/BUILD
@ -54,9 +54,27 @@ grpc_cc_library(
    testonly = True,
    srcs = ["dns_test.cc"],
    hdrs = ["dns_test.h"],
+    data = [
+        "dns_test_record_groups.yaml",
+        "//test/cpp/naming/utils:dns_resolver",
+        "//test/cpp/naming/utils:dns_server",
+        "//test/cpp/naming/utils:health_check",
+        "//test/cpp/naming/utils:tcp_connect",
+    ],
+    external_deps = [
+        "absl/status:statusor",
+        "absl/strings",
+        "absl/strings:str_format",
+        "address_sorting",
+    ],
    deps = [
+        "//src/core:env",
        "//test/core/event_engine:event_engine_test_utils",
        "//test/core/event_engine/test_suite:event_engine_test_framework",
+        "//test/core/util:fake_udp_and_tcp_server",
+        "//test/core/util:grpc_test_util_base",
+        "//test/cpp/util:get_grpc_test_runfile_dir",
+        "//test/cpp/util:test_util",
    ],
    alwayslink = 1,
 )
--- a/test/core/event_engine/test_suite/tests/dns_test.cc
+++ b/test/core/event_engine/test_suite/tests/dns_test.cc
@ -12,10 +12,36 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

-#include <gtest/gtest.h>
+// IWYU pragma: no_include <ratio>
+// IWYU pragma: no_include <arpa/inet.h>

-#include "src/core/lib/iomgr/exec_ctx.h"
+#include <cstdlib>
+#include <cstring>
+#include <initializer_list>
+#include <memory>
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include "absl/status/status.h"
+#include "absl/status/statusor.h"
+#include "absl/strings/str_format.h"
+#include "absl/strings/str_join.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+#include <grpc/event_engine/event_engine.h>
+
+#include "src/core/lib/event_engine/tcp_socket_utils.h"
+#include "src/core/lib/gprpp/notification.h"
+#include "src/core/lib/iomgr/sockaddr.h"
 #include "test/core/event_engine/test_suite/event_engine_test_framework.h"
+#include "test/core/util/fake_udp_and_tcp_server.h"
+#include "test/core/util/port.h"
+#include "test/cpp/util/get_grpc_test_runfile_dir.h"
+#include "test/cpp/util/subprocess.h"

 namespace grpc_event_engine {
 namespace experimental {
@ -25,7 +51,493 @@ void InitDNSTests() {}
 }  // namespace experimental
 }  // namespace grpc_event_engine

+#ifdef GPR_WINDOWS
 class EventEngineDNSTest : public EventEngineTest {};

-// TODO(hork): establish meaningful tests
-TEST_F(EventEngineDNSTest, TODO) { grpc_core::ExecCtx exec_ctx; }
+// TODO(yijiem): make the test run on Windows
+TEST_F(EventEngineDNSTest, TODO) {}
+#else
+
+namespace {
+
+using grpc_event_engine::experimental::EventEngine;
+using grpc_event_engine::experimental::URIToResolvedAddress;
+using SRVRecord = EventEngine::DNSResolver::SRVRecord;
+using testing::ElementsAre;
+using testing::Pointwise;
+using testing::SizeIs;
+using testing::UnorderedPointwise;
+
+// TODO(yijiem): make this portable for Windows
+constexpr char kDNSTestRecordGroupsYamlPath[] =
+    "test/core/event_engine/test_suite/tests/dns_test_record_groups.yaml";
+// Invoke bazel's executable links to the .sh and .py scripts (don't use
+// the .sh and .py suffixes) to make sure that we're using bazel's test
+// environment.
+constexpr char kDNSServerRelPath[] = "test/cpp/naming/utils/dns_server";
+constexpr char kDNSResolverRelPath[] = "test/cpp/naming/utils/dns_resolver";
+constexpr char kTCPConnectRelPath[] = "test/cpp/naming/utils/tcp_connect";
+constexpr char kHealthCheckRelPath[] = "test/cpp/naming/utils/health_check";
+
+MATCHER(ResolvedAddressEq, "") {
+  const auto& addr0 = std::get<0>(arg);
+  const auto& addr1 = std::get<1>(arg);
+  return addr0.size() == addr1.size() &&
+         memcmp(addr0.address(), addr1.address(), addr0.size()) == 0;
+}
+
+MATCHER(SRVRecordEq, "") {
+  const auto& arg0 = std::get<0>(arg);
+  const auto& arg1 = std::get<1>(arg);
+  return arg0.host == arg1.host && arg0.port == arg1.port &&
+         arg0.priority == arg1.priority && arg0.weight == arg1.weight;
+}
+
+MATCHER(StatusCodeEq, "") {
+  return std::get<0>(arg).code() == std::get<1>(arg);
+}
+
+}  // namespace
+
+class EventEngineDNSTest : public EventEngineTest {
+ protected:
+  static void SetUpTestSuite() {
+    std::string test_records_path = kDNSTestRecordGroupsYamlPath;
+    std::string dns_server_path = kDNSServerRelPath;
+    std::string dns_resolver_path = kDNSResolverRelPath;
+    std::string tcp_connect_path = kTCPConnectRelPath;
+    std::string health_check_path = kHealthCheckRelPath;
+    absl::optional<std::string> runfile_dir = grpc::GetGrpcTestRunFileDir();
+    if (runfile_dir.has_value()) {
+      // We sure need a portable filesystem lib for this to work on Windows.
+      test_records_path = absl::StrJoin({*runfile_dir, test_records_path}, "/");
+      dns_server_path = absl::StrJoin({*runfile_dir, dns_server_path}, "/");
+      dns_resolver_path = absl::StrJoin({*runfile_dir, dns_resolver_path}, "/");
+      tcp_connect_path = absl::StrJoin({*runfile_dir, tcp_connect_path}, "/");
+      health_check_path = absl::StrJoin({*runfile_dir, health_check_path}, "/");
+    } else {
+      // Invoke the .py scripts directly where they are in source code if we are
+      // not running with bazel.
+      dns_server_path += ".py";
+      dns_resolver_path += ".py";
+      tcp_connect_path += ".py";
+      health_check_path += ".py";
+    }
+    // 1. launch dns_server
+    int port = grpc_pick_unused_port_or_die();
+    // <path to dns_server.py> -p <port> -r <path to records config>
+    dns_server_.server_process = new grpc::SubProcess(
+        {dns_server_path, "-p", std::to_string(port), "-r", test_records_path});
+    dns_server_.port = port;
+
+    // 2. wait until dns_server is up (health check)
+    grpc::SubProcess health_check({
+        health_check_path,
+        "-p",
+        std::to_string(port),
+        "--dns_resolver_bin_path",
+        dns_resolver_path,
+        "--tcp_connect_bin_path",
+        tcp_connect_path,
+    });
+    int status = health_check.Join();
+    // TODO(yijiem): make this portable for Windows
+    ASSERT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+
+  static void TearDownTestSuite() {
+    dns_server_.server_process->Interrupt();
+    dns_server_.server_process->Join();
+    delete dns_server_.server_process;
+  }
+
+  std::unique_ptr<EventEngine::DNSResolver> CreateDefaultDNSResolver() {
+    std::shared_ptr<EventEngine> test_ee(this->NewEventEngine());
+    EventEngine::DNSResolver::ResolverOptions options;
+    options.dns_server = dns_server_.address();
+    return *test_ee->GetDNSResolver(options);
+  }
+
+  std::unique_ptr<EventEngine::DNSResolver>
+  CreateDNSResolverWithNonResponsiveServer() {
+    using FakeUdpAndTcpServer = grpc_core::testing::FakeUdpAndTcpServer;
+    // Start up fake non responsive DNS server
+    fake_dns_server_ = std::make_unique<FakeUdpAndTcpServer>(
+        FakeUdpAndTcpServer::AcceptMode::kWaitForClientToSendFirstBytes,
+        FakeUdpAndTcpServer::CloseSocketUponCloseFromPeer);
+    const std::string dns_server =
+        absl::StrFormat("[::1]:%d", fake_dns_server_->port());
+    std::shared_ptr<EventEngine> test_ee(this->NewEventEngine());
+    EventEngine::DNSResolver::ResolverOptions options;
+    options.dns_server = dns_server;
+    return *test_ee->GetDNSResolver(options);
+  }
+
+  std::unique_ptr<EventEngine::DNSResolver>
+  CreateDNSResolverWithoutSpecifyingServer() {
+    std::shared_ptr<EventEngine> test_ee(this->NewEventEngine());
+    EventEngine::DNSResolver::ResolverOptions options;
+    return *test_ee->GetDNSResolver(options);
+  }
+
+  struct DNSServer {
+    std::string address() { return "127.0.0.1:" + std::to_string(port); }
+    int port;
+    grpc::SubProcess* server_process;
+  };
+  grpc_core::Notification dns_resolver_signal_;
+
+ private:
+  static DNSServer dns_server_;
+  std::unique_ptr<grpc_core::testing::FakeUdpAndTcpServer> fake_dns_server_;
+};
+
+EventEngineDNSTest::DNSServer EventEngineDNSTest::dns_server_;
+
+TEST_F(EventEngineDNSTest, QueryNXHostname) {
+  auto dns_resolver = CreateDefaultDNSResolver();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        ASSERT_FALSE(result.ok());
+        EXPECT_EQ(result.status(),
+                  absl::NotFoundError("address lookup failed for "
+                                      "nonexisting-target.dns-test.event-"
+                                      "engine.: Domain name not found"));
+        dns_resolver_signal_.Notify();
+      },
+      "nonexisting-target.dns-test.event-engine.", /*default_port=*/"443");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, QueryWithIPLiteral) {
+  auto dns_resolver = CreateDefaultDNSResolver();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        ASSERT_TRUE(result.ok());
+        EXPECT_THAT(*result,
+                    Pointwise(ResolvedAddressEq(),
+                              {*URIToResolvedAddress("ipv4:4.3.2.1:1234")}));
+        dns_resolver_signal_.Notify();
+      },
+      "4.3.2.1:1234",
+      /*default_port=*/"");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, QueryARecord) {
+  auto dns_resolver = CreateDefaultDNSResolver();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        ASSERT_TRUE(result.ok());
+        EXPECT_THAT(*result, UnorderedPointwise(
+                                 ResolvedAddressEq(),
+                                 {*URIToResolvedAddress("ipv4:1.2.3.4:443"),
+                                  *URIToResolvedAddress("ipv4:1.2.3.5:443"),
+                                  *URIToResolvedAddress("ipv4:1.2.3.6:443")}));
+        dns_resolver_signal_.Notify();
+      },
+      "ipv4-only-multi-target.dns-test.event-engine.",
+      /*default_port=*/"443");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, QueryAAAARecord) {
+  auto dns_resolver = CreateDefaultDNSResolver();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        ASSERT_TRUE(result.ok());
+        EXPECT_THAT(
+            *result,
+            UnorderedPointwise(
+                ResolvedAddressEq(),
+                {*URIToResolvedAddress("ipv6:[2607:f8b0:400a:801::1002]:443"),
+                 *URIToResolvedAddress("ipv6:[2607:f8b0:400a:801::1003]:443"),
+                 *URIToResolvedAddress(
+                     "ipv6:[2607:f8b0:400a:801::1004]:443")}));
+        dns_resolver_signal_.Notify();
+      },
+      "ipv6-only-multi-target.dns-test.event-engine.:443",
+      /*default_port=*/"");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, TestAddressSorting) {
+  auto dns_resolver = CreateDefaultDNSResolver();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        ASSERT_TRUE(result.ok());
+        EXPECT_THAT(
+            *result,
+            Pointwise(ResolvedAddressEq(),
+                      {*URIToResolvedAddress("ipv6:[::1]:1234"),
+                       *URIToResolvedAddress("ipv6:[2002::1111]:1234")}));
+        dns_resolver_signal_.Notify();
+      },
+      "ipv6-loopback-preferred-target.dns-test.event-engine.:1234",
+      /*default_port=*/"");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, QuerySRVRecord) {
+  const SRVRecord kExpectedRecords[] = {
+      {/*host=*/"ipv4-only-multi-target.dns-test.event-engine", /*port=*/1234,
+       /*priority=*/0, /*weight=*/0},
+      {"ipv6-only-multi-target.dns-test.event-engine", 1234, 0, 0},
+  };
+
+  auto dns_resolver = CreateDefaultDNSResolver();
+  dns_resolver->LookupSRV(
+      [&kExpectedRecords, this](auto result) {
+        ASSERT_TRUE(result.ok());
+        EXPECT_THAT(*result, Pointwise(SRVRecordEq(), kExpectedRecords));
+        dns_resolver_signal_.Notify();
+      },
+      "_grpclb._tcp.srv-multi-target.dns-test.event-engine.");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, QuerySRVRecordWithLocalhost) {
+  auto dns_resolver = CreateDefaultDNSResolver();
+  dns_resolver->LookupSRV(
+      [this](auto result) {
+        ASSERT_TRUE(result.ok());
+        EXPECT_THAT(*result, SizeIs(0));
+        dns_resolver_signal_.Notify();
+      },
+      "localhost:1000");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, QueryTXTRecord) {
+  // clang-format off
+  const std::string kExpectedRecord =
+      "grpc_config=[{"
+        "\"serviceConfig\":{"
+          "\"loadBalancingPolicy\":\"round_robin\","
+          "\"methodConfig\":[{"
+            "\"name\":[{"
+              "\"method\":\"Foo\","
+              "\"service\":\"SimpleService\""
+            "}],"
+            "\"waitForReady\":true"
+          "}]"
+        "}"
+      "}]";
+  // clang-format on
+
+  auto dns_resolver = CreateDefaultDNSResolver();
+  dns_resolver->LookupTXT(
+      [&kExpectedRecord, this](auto result) {
+        ASSERT_TRUE(result.ok());
+        EXPECT_THAT(*result,
+                    ElementsAre(kExpectedRecord, "other_config=other config"));
+        dns_resolver_signal_.Notify();
+      },
+      "_grpc_config.simple-service.dns-test.event-engine.");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, QueryTXTRecordWithLocalhost) {
+  auto dns_resolver = CreateDefaultDNSResolver();
+  dns_resolver->LookupTXT(
+      [this](auto result) {
+        ASSERT_TRUE(result.ok());
+        EXPECT_THAT(*result, SizeIs(0));
+        dns_resolver_signal_.Notify();
+      },
+      "localhost:1000");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, TestCancelActiveDNSQuery) {
+  const std::string name = "dont-care-since-wont-be-resolved.test.com:1234";
+  auto dns_resolver = CreateDNSResolverWithNonResponsiveServer();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        ASSERT_FALSE(result.ok());
+        EXPECT_EQ(result.status(),
+                  absl::CancelledError("address lookup failed for "
+                                       "dont-care-since-wont-be-resolved.test."
+                                       "com:1234: DNS query cancelled"));
+        dns_resolver_signal_.Notify();
+      },
+      name, "1234");
+  dns_resolver.reset();
+  dns_resolver_signal_.WaitForNotification();
+}
+
+#define EXPECT_SUCCESS()           \
+  do {                             \
+    EXPECT_TRUE(result.ok());      \
+    EXPECT_FALSE(result->empty()); \
+  } while (0)
+
+// The following tests are almost 1-to-1 ported from
+// test/core/iomgr/resolve_address_test.cc (except tests for the native DNS
+// resolver and tests that would not make sense using the
+// EventEngine::DNSResolver API).
+
+// START
+TEST_F(EventEngineDNSTest, LocalHost) {
+  auto dns_resolver = CreateDNSResolverWithoutSpecifyingServer();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        EXPECT_SUCCESS();
+        dns_resolver_signal_.Notify();
+      },
+      "localhost:1", "");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, DefaultPort) {
+  auto dns_resolver = CreateDNSResolverWithoutSpecifyingServer();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        EXPECT_SUCCESS();
+        dns_resolver_signal_.Notify();
+      },
+      "localhost", "1");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+// This test assumes the environment has an ipv6 loopback
+TEST_F(EventEngineDNSTest, LocalhostResultHasIPv6First) {
+  auto dns_resolver = CreateDNSResolverWithoutSpecifyingServer();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        EXPECT_TRUE(result.ok());
+        EXPECT_TRUE(!result->empty() &&
+                    (*result)[0].address()->sa_family == AF_INET6);
+        dns_resolver_signal_.Notify();
+      },
+      "localhost:1", "");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, NonNumericDefaultPort) {
+  auto dns_resolver = CreateDNSResolverWithoutSpecifyingServer();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        EXPECT_SUCCESS();
+        dns_resolver_signal_.Notify();
+      },
+      "localhost", "http");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, MissingDefaultPort) {
+  auto dns_resolver = CreateDNSResolverWithoutSpecifyingServer();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        EXPECT_FALSE(result.ok());
+        dns_resolver_signal_.Notify();
+      },
+      "localhost", "");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, IPv6WithPort) {
+  auto dns_resolver = CreateDNSResolverWithoutSpecifyingServer();
+  dns_resolver->LookupHostname(
+      [this](auto result) {
+        EXPECT_SUCCESS();
+        dns_resolver_signal_.Notify();
+      },
+      "[2001:db8::1]:1", "");
+  dns_resolver_signal_.WaitForNotification();
+}
+
+void TestIPv6WithoutPort(std::unique_ptr<EventEngine::DNSResolver> dns_resolver,
+                         grpc_core::Notification* barrier,
+                         absl::string_view target) {
+  dns_resolver->LookupHostname(
+      [barrier](auto result) {
+        EXPECT_TRUE(result.ok());
+        EXPECT_FALSE(result->empty());
+        barrier->Notify();
+      },
+      target, "80");
+  barrier->WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, IPv6WithoutPortNoBrackets) {
+  TestIPv6WithoutPort(CreateDNSResolverWithoutSpecifyingServer(),
+                      &dns_resolver_signal_, "2001:db8::1");
+}
+
+TEST_F(EventEngineDNSTest, IPv6WithoutPortWithBrackets) {
+  TestIPv6WithoutPort(CreateDNSResolverWithoutSpecifyingServer(),
+                      &dns_resolver_signal_, "[2001:db8::1]");
+}
+
+TEST_F(EventEngineDNSTest, IPv6WithoutPortV4MappedV6) {
+  TestIPv6WithoutPort(CreateDNSResolverWithoutSpecifyingServer(),
+                      &dns_resolver_signal_, "2001:db8::1.2.3.4");
+}
+
+void TestInvalidIPAddress(
+    std::unique_ptr<EventEngine::DNSResolver> dns_resolver,
+    grpc_core::Notification* barrier, absl::string_view target) {
+  dns_resolver->LookupHostname(
+      [barrier](auto result) {
+        EXPECT_FALSE(result.ok());
+        barrier->Notify();
+      },
+      target, "");
+  barrier->WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, InvalidIPv4Addresses) {
+  TestInvalidIPAddress(CreateDNSResolverWithoutSpecifyingServer(),
+                       &dns_resolver_signal_, "293.283.1238.3:1");
+}
+
+TEST_F(EventEngineDNSTest, InvalidIPv6Addresses) {
+  TestInvalidIPAddress(CreateDNSResolverWithoutSpecifyingServer(),
+                       &dns_resolver_signal_, "[2001:db8::11111]:1");
+}
+
+void TestUnparseableHostPort(
+    std::unique_ptr<EventEngine::DNSResolver> dns_resolver,
+    grpc_core::Notification* barrier, absl::string_view target) {
+  dns_resolver->LookupHostname(
+      [barrier](auto result) {
+        EXPECT_FALSE(result.ok());
+        barrier->Notify();
+      },
+      target, "1");
+  barrier->WaitForNotification();
+}
+
+TEST_F(EventEngineDNSTest, UnparseableHostPortsOnlyBracket) {
+  TestUnparseableHostPort(CreateDNSResolverWithoutSpecifyingServer(),
+                          &dns_resolver_signal_, "[");
+}
+
+TEST_F(EventEngineDNSTest, UnparseableHostPortsMissingRightBracket) {
+  TestUnparseableHostPort(CreateDNSResolverWithoutSpecifyingServer(),
+                          &dns_resolver_signal_, "[::1");
+}
+
+TEST_F(EventEngineDNSTest, UnparseableHostPortsBadPort) {
+  TestUnparseableHostPort(CreateDNSResolverWithoutSpecifyingServer(),
+                          &dns_resolver_signal_, "[::1]bad");
+}
+
+TEST_F(EventEngineDNSTest, UnparseableHostPortsBadIPv6) {
+  TestUnparseableHostPort(CreateDNSResolverWithoutSpecifyingServer(),
+                          &dns_resolver_signal_, "[1.2.3.4]");
+}
+
+TEST_F(EventEngineDNSTest, UnparseableHostPortsBadLocalhost) {
+  TestUnparseableHostPort(CreateDNSResolverWithoutSpecifyingServer(),
+                          &dns_resolver_signal_, "[localhost]");
+}
+
+TEST_F(EventEngineDNSTest, UnparseableHostPortsBadLocalhostWithPort) {
+  TestUnparseableHostPort(CreateDNSResolverWithoutSpecifyingServer(),
+                          &dns_resolver_signal_, "[localhost]:1");
+}
+// END
+
+#endif  // GPR_WINDOWS
--- a/test/core/event_engine/test_suite/tests/dns_test_record_groups.yaml
+++ b/test/core/event_engine/test_suite/tests/dns_test_record_groups.yaml
@ -0,0 +1,21 @@
+resolver_tests_common_zone_name: dns-test.event-engine.
+resolver_component_tests:
+- records:
+    ipv4-only-multi-target:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+    - {TTL: '2100', data: 1.2.3.5, type: A}
+    - {TTL: '2100', data: 1.2.3.6, type: A}
+    ipv6-only-multi-target:
+    - {TTL: '2100', data: '2607:f8b0:400a:801::1002', type: AAAA}
+    - {TTL: '2100', data: '2607:f8b0:400a:801::1003', type: AAAA}
+    - {TTL: '2100', data: '2607:f8b0:400a:801::1004', type: AAAA}
+    ipv6-loopback-preferred-target:
+    - {TTL: '2100', data: '2002::1111', type: AAAA}
+    - {TTL: '2100', data: '::1', type: AAAA}
+    _grpclb._tcp.srv-multi-target:
+    - {TTL: '2100', data: 0 0 1234 ipv4-only-multi-target, type: SRV}
+    - {TTL: '2100', data: 0 0 1234 ipv6-only-multi-target, type: SRV}
+    _grpc_config.simple-service:
+    - {TTL: '2100', data: 'grpc_config=[{"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"SimpleService"}],"waitForReady":true}]}}]',
+      type: TXT}
+    - {TTL: '2100', data: 'other_config=other config', type: TXT}
--- a/test/core/http/httpcli_test.cc
+++ b/test/core/http/httpcli_test.cc
@ -241,7 +241,7 @@ TEST_F(HttpRequestTest, Post) {

 int g_fake_non_responsive_dns_server_port;

-void InjectNonResponsiveDNSServer(ares_channel channel) {
+void InjectNonResponsiveDNSServer(ares_channel* channel) {
  gpr_log(GPR_DEBUG,
          "Injecting broken nameserver list. Bad server address:|[::1]:%d|.",
          g_fake_non_responsive_dns_server_port);
@ -253,7 +253,8 @@ void InjectNonResponsiveDNSServer(ares_channel channel) {
  dns_server_addrs[0].tcp_port = g_fake_non_responsive_dns_server_port;
  dns_server_addrs[0].udp_port = g_fake_non_responsive_dns_server_port;
  dns_server_addrs[0].next = nullptr;
-  GPR_ASSERT(ares_set_servers_ports(channel, dns_server_addrs) == ARES_SUCCESS);
+  GPR_ASSERT(ares_set_servers_ports(*channel, dns_server_addrs) ==
+             ARES_SUCCESS);
 }

 TEST_F(HttpRequestTest, CancelGetDuringDNSResolution) {
@ -263,7 +264,7 @@ TEST_F(HttpRequestTest, CancelGetDuringDNSResolution) {
          kWaitForClientToSendFirstBytes,
      grpc_core::testing::FakeUdpAndTcpServer::CloseSocketUponCloseFromPeer);
  g_fake_non_responsive_dns_server_port = fake_dns_server.port();
-  void (*prev_test_only_inject_config)(ares_channel channel) =
+  void (*prev_test_only_inject_config)(ares_channel * channel) =
      grpc_ares_test_only_inject_config;
  grpc_ares_test_only_inject_config = InjectNonResponsiveDNSServer;
  // Run the same test on several threads in parallel to try to trigger races
--- a/test/core/iomgr/resolve_address_test.cc
+++ b/test/core/iomgr/resolve_address_test.cc
@ -176,7 +176,7 @@ class ResolveAddressTest : public ::testing::Test {
  grpc_pollset_set* pollset_set_;
  // the default value of grpc_ares_test_only_inject_config, which might
  // be modified during a test
-  void (*default_inject_config_)(ares_channel channel) = nullptr;
+  void (*default_inject_config_)(ares_channel* channel) = nullptr;
 };

 }  // namespace
@ -390,7 +390,7 @@ namespace {

 int g_fake_non_responsive_dns_server_port;

-void InjectNonResponsiveDNSServer(ares_channel channel) {
+void InjectNonResponsiveDNSServer(ares_channel* channel) {
  gpr_log(GPR_DEBUG,
          "Injecting broken nameserver list. Bad server address:|[::1]:%d|.",
          g_fake_non_responsive_dns_server_port);
@ -403,7 +403,7 @@ void InjectNonResponsiveDNSServer(ares_channel channel) {
  dns_server_addrs[0].tcp_port = g_fake_non_responsive_dns_server_port;
  dns_server_addrs[0].udp_port = g_fake_non_responsive_dns_server_port;
  dns_server_addrs[0].next = nullptr;
-  ASSERT_EQ(ares_set_servers_ports(channel, dns_server_addrs), ARES_SUCCESS);
+  ASSERT_EQ(ares_set_servers_ports(*channel, dns_server_addrs), ARES_SUCCESS);
 }

 }  // namespace
--- a/test/cpp/naming/BUILD
+++ b/test/cpp/naming/BUILD
@ -38,6 +38,7 @@ grpc_cc_test(
    name = "cancel_ares_query_test",
    srcs = ["cancel_ares_query_test.cc"],
    external_deps = ["gtest"],
+    tags = ["cancel_ares_query_test"],
    deps = [
        "//:gpr",
        "//:grpc",
--- a/test/cpp/naming/cancel_ares_query_test.cc
+++ b/test/cpp/naming/cancel_ares_query_test.cc
@ -39,6 +39,7 @@
 #include "src/core/lib/debug/stats.h"
 #include "src/core/lib/debug/stats_data.h"
 #include "src/core/lib/event_engine/default_event_engine.h"
+#include "src/core/lib/experiments/experiments.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/gprpp/crash.h"
 #include "src/core/lib/gprpp/orphanable.h"
@ -54,6 +55,7 @@
 #include "test/core/util/fake_udp_and_tcp_server.h"
 #include "test/core/util/port.h"
 #include "test/core/util/test_config.h"
+#include "test/cpp/util/test_config.h"

 #ifdef GPR_WINDOWS
 #include "src/core/lib/iomgr/sockaddr_windows.h"
@ -310,8 +312,13 @@ void TestCancelDuringActiveQuery(
    // The DNS resolution timeout should fire well before the
    // RPC's deadline expires.
    expected_status_code = GRPC_STATUS_UNAVAILABLE;
-    expected_error_message_substring =
-        absl::StrCat("DNS resolution failed for ", name);
+    if (grpc_core::IsEventEngineDnsEnabled()) {
+      expected_error_message_substring =
+          absl::StrCat("errors resolving ", name);
+    } else {
+      expected_error_message_substring =
+          absl::StrCat("DNS resolution failed for ", name);
+    }
    grpc_arg arg;
    arg.type = GRPC_ARG_INTEGER;
    arg.key = const_cast<char*>(GRPC_ARG_DNS_ARES_QUERY_TIMEOUT_MS);
@ -424,8 +431,9 @@ TEST_F(
 }  // namespace

 int main(int argc, char** argv) {
-  grpc::testing::TestEnvironment env(&argc, argv);
  ::testing::InitGoogleTest(&argc, argv);
+  grpc::testing::InitTest(&argc, &argv, true);
+  grpc::testing::TestEnvironment env(&argc, argv);
  auto result = RUN_ALL_TESTS();
  return result;
 }
--- a/test/cpp/naming/generate_resolver_component_tests.bzl
+++ b/test/cpp/naming/generate_resolver_component_tests.bzl
@ -21,6 +21,10 @@ load("//bazel:grpc_build_system.bzl", "grpc_cc_binary", "grpc_cc_test")

 # buildifier: disable=unnamed-macro
 def generate_resolver_component_tests():
+    """Generate address_sorting_test and resolver_component_test suite with different configurations.
+
+    Note that the resolver_component_test suite's configuration is 2 dimensional: security and whether to enable the event_engine_dns experiment.
+    """
    for unsecure_build_config_suffix in ["_unsecure", ""]:
        grpc_cc_test(
            name = "address_sorting_test%s" % unsecure_build_config_suffix,
@ -58,6 +62,7 @@ def generate_resolver_component_tests():
                "//:grpc++%s" % unsecure_build_config_suffix,
                "//:grpc%s" % unsecure_build_config_suffix,
                "//:gpr",
+                "//src/core:ares_resolver",
                "//test/cpp/util:test_config",
            ],
            tags = ["no_windows"],
@ -84,7 +89,7 @@ def generate_resolver_component_tests():
                "//test/cpp/naming/utils:dns_server",
                "//test/cpp/naming/utils:dns_resolver",
                "//test/cpp/naming/utils:tcp_connect",
-                "resolver_test_record_groups.yaml",  # include the transitive dependency so that the dns sever py binary can locate this
+                "resolver_test_record_groups.yaml",  # include the transitive dependency so that the dns server py binary can locate this
            ],
            args = [
                "--test_bin_name=resolver_component_test%s" % unsecure_build_config_suffix,
@ -93,5 +98,5 @@ def generate_resolver_component_tests():
            # The test is highly flaky on AWS workers that we use for running ARM64 tests.
            # The "no_arm64" tag can be used to skip it.
            # (see https://github.com/grpc/grpc/issues/25289).
-            tags = ["no_windows", "no_mac", "no_arm64"],
+            tags = ["no_windows", "no_mac", "no_arm64", "resolver_component_tests_runner_invoker"],
        )
--- a/test/cpp/naming/resolver_component_test.cc
+++ b/test/cpp/naming/resolver_component_test.cc
@ -47,7 +47,9 @@
 #include "src/core/lib/address_utils/sockaddr_utils.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/config/core_configuration.h"
+#include "src/core/lib/event_engine/ares_resolver.h"
 #include "src/core/lib/event_engine/default_event_engine.h"
+#include "src/core/lib/experiments/experiments.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/gprpp/crash.h"
 #include "src/core/lib/gprpp/host_port.h"
@ -255,11 +257,20 @@ void PollPollsetUntilRequestDone(ArgsStruct* args) {
    GPR_ASSERT(gpr_time_cmp(time_left, gpr_time_0(GPR_TIMESPAN)) >= 0);
    grpc_pollset_worker* worker = nullptr;
    grpc_core::ExecCtx exec_ctx;
-    GRPC_LOG_IF_ERROR(
-        "pollset_work",
-        grpc_pollset_work(
-            args->pollset, &worker,
-            grpc_core::Timestamp::FromTimespecRoundUp(NSecondDeadline(1))));
+    if (grpc_core::IsEventEngineDnsEnabled()) {
+      // This essentially becomes a condition variable.
+      GRPC_LOG_IF_ERROR(
+          "pollset_work",
+          grpc_pollset_work(
+              args->pollset, &worker,
+              grpc_core::Timestamp::FromTimespecRoundUp(deadline)));
+    } else {
+      GRPC_LOG_IF_ERROR(
+          "pollset_work",
+          grpc_pollset_work(
+              args->pollset, &worker,
+              grpc_core::Timestamp::FromTimespecRoundUp(NSecondDeadline(1))));
+    }
  }
  gpr_event_set(&args->ev, reinterpret_cast<void*>(1));
 }
@ -529,7 +540,7 @@ int g_fake_non_responsive_dns_server_port = -1;
 // resolver. This is useful to effectively mock /etc/resolv.conf settings
 // (and equivalent on Windows), which unit tests don't have write permissions.
 //
-void InjectBrokenNameServerList(ares_channel channel) {
+void InjectBrokenNameServerList(ares_channel* channel) {
  struct ares_addr_port_node dns_server_addrs[2];
  memset(dns_server_addrs, 0, sizeof(dns_server_addrs));
  std::string unused_host;
@ -558,7 +569,8 @@ void InjectBrokenNameServerList(ares_channel channel) {
  dns_server_addrs[1].tcp_port = atoi(local_dns_server_port.c_str());
  dns_server_addrs[1].udp_port = atoi(local_dns_server_port.c_str());
  dns_server_addrs[1].next = nullptr;
-  GPR_ASSERT(ares_set_servers_ports(channel, dns_server_addrs) == ARES_SUCCESS);
+  GPR_ASSERT(ares_set_servers_ports(*channel, dns_server_addrs) ==
+             ARES_SUCCESS);
 }

 void StartResolvingLocked(grpc_core::Resolver* r) { r->StartLocked(); }
@ -591,7 +603,12 @@ void RunResolvesRelevantRecordsTest(
        grpc_core::testing::FakeUdpAndTcpServer::CloseSocketUponCloseFromPeer);
    g_fake_non_responsive_dns_server_port =
        fake_non_responsive_dns_server->port();
-    grpc_ares_test_only_inject_config = InjectBrokenNameServerList;
+    if (grpc_core::IsEventEngineDnsEnabled()) {
+      event_engine_grpc_ares_test_only_inject_config =
+          InjectBrokenNameServerList;
+    } else {
+      grpc_ares_test_only_inject_config = InjectBrokenNameServerList;
+    }
    whole_uri = absl::StrCat("dns:///", absl::GetFlag(FLAGS_target_name));
  } else if (absl::GetFlag(FLAGS_inject_broken_nameserver_list) == "False") {
    gpr_log(GPR_INFO, "Specifying authority in uris to: %s",
@ -673,13 +690,15 @@ TEST(ResolverComponentTest, TestDoesntCrashOrHangWith1MsTimeout) {
 }  // namespace

 int main(int argc, char** argv) {
-  grpc_init();
-  grpc::testing::TestEnvironment env(&argc, argv);
  ::testing::InitGoogleTest(&argc, argv);
+  // Need before TestEnvironment construct for --grpc_experiments flag at
+  // least.
  grpc::testing::InitTest(&argc, &argv, true);
+  grpc::testing::TestEnvironment env(&argc, argv);
  if (absl::GetFlag(FLAGS_target_name).empty()) {
    grpc_core::Crash("Missing target_name param.");
  }
+  grpc_init();
  auto result = RUN_ALL_TESTS();
  grpc_shutdown();
  return result;
--- a/test/cpp/naming/resolver_component_tests_runner.py
+++ b/test/cpp/naming/resolver_component_tests_runner.py
@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Copyright 2015 gRPC authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@ -58,6 +58,9 @@ if cur_resolver and cur_resolver != 'ares':
  test_runner_log('Exit 1 without running tests.')
  sys.exit(1)
 os.environ.update({'GRPC_TRACE': 'cares_resolver,cares_address_sorting'})
+experiments = os.environ.get('GRPC_EXPERIMENTS')
+if experiments is not None and 'event_engine_dns' in experiments:
+  os.environ.update({'GRPC_TRACE': 'event_engine_client_channel_resolver,cares_resolver'})

 def wait_until_dns_server_is_up(args,
                                dns_server_subprocess,
--- a/test/cpp/naming/utils/BUILD
+++ b/test/cpp/naming/utils/BUILD
@ -48,3 +48,9 @@ grpc_py_binary(
    testonly = True,
    srcs = ["tcp_connect.py"],
 )
+
+grpc_py_binary(
+    name = "health_check",
+    testonly = True,
+    srcs = ["health_check.py"],
+)
--- a/test/cpp/naming/utils/dns_resolver.py
+++ b/test/cpp/naming/utils/dns_resolver.py
@ -1,4 +1,4 @@
-#!/usr/bin/env python2.7
+#!/usr/bin/env python3
 # Copyright 2015 gRPC authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
--- a/test/cpp/naming/utils/dns_server.py
+++ b/test/cpp/naming/utils/dns_server.py
@ -1,4 +1,4 @@
-#!/usr/bin/env python2.7
+#!/usr/bin/env python3
 # Copyright 2015 gRPC authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
--- a/test/cpp/naming/utils/health_check.py
+++ b/test/cpp/naming/utils/health_check.py
@ -0,0 +1,121 @@
+#!/usr/bin/env python3
+# Copyright 2023 The 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.
+
+import argparse
+import platform
+import subprocess
+import sys
+import time
+
+
+def test_runner_log(msg):
+    sys.stderr.write("\n%s: %s\n" % (__file__, msg))
+
+
+def python_args(arg_list):
+    if platform.system() == "Windows":
+        return [sys.executable] + arg_list
+    return arg_list
+
+
+def wait_until_dns_server_is_up(args):
+    for i in range(0, 30):
+        test_runner_log(
+            "Health check: attempt to connect to DNS server over TCP."
+        )
+        tcp_connect_subprocess = subprocess.Popen(
+            python_args(
+                [
+                    args.tcp_connect_bin_path,
+                    "--server_host",
+                    "127.0.0.1",
+                    "--server_port",
+                    str(args.dns_server_port),
+                    "--timeout",
+                    str(1),
+                ]
+            )
+        )
+        tcp_connect_subprocess.communicate()
+        if tcp_connect_subprocess.returncode == 0:
+            test_runner_log(
+                (
+                    "Health check: attempt to make an A-record "
+                    "query to DNS server."
+                )
+            )
+            dns_resolver_subprocess = subprocess.Popen(
+                python_args(
+                    [
+                        args.dns_resolver_bin_path,
+                        "--qname",
+                        "health-check-local-dns-server-is-alive.resolver-tests.grpctestingexp",
+                        "--server_host",
+                        "127.0.0.1",
+                        "--server_port",
+                        str(args.dns_server_port),
+                    ]
+                ),
+                stdout=subprocess.PIPE,
+            )
+            dns_resolver_stdout, _ = dns_resolver_subprocess.communicate(
+                str.encode("ascii")
+            )
+            if dns_resolver_subprocess.returncode == 0:
+                if "123.123.123.123".encode("ascii") in dns_resolver_stdout:
+                    test_runner_log(
+                        (
+                            "DNS server is up! "
+                            "Successfully reached it over UDP and TCP."
+                        )
+                    )
+                return
+        time.sleep(1)
+    test_runner_log(
+        (
+            "Failed to reach DNS server over TCP and/or UDP. "
+            "Exitting without running tests."
+        )
+    )
+    sys.exit(1)
+
+
+def main():
+    argp = argparse.ArgumentParser(description="Make DNS queries for A records")
+    argp.add_argument(
+        "-p",
+        "--dns_server_port",
+        default=None,
+        type=int,
+        help=("Port that local DNS server is listening on."),
+    )
+    argp.add_argument(
+        "--dns_resolver_bin_path",
+        default=None,
+        type=str,
+        help=("Path to the DNS health check utility."),
+    )
+    argp.add_argument(
+        "--tcp_connect_bin_path",
+        default=None,
+        type=str,
+        help=("Path to the TCP health check utility."),
+    )
+    args = argp.parse_args()
+    wait_until_dns_server_is_up(args)
+
+
+if __name__ == "__main__":
+    main()
--- a/test/cpp/naming/utils/run_dns_server_for_lb_interop_tests.py
+++ b/test/cpp/naming/utils/run_dns_server_for_lb_interop_tests.py
@ -1,4 +1,4 @@
-#!/usr/bin/env python2.7
+#!/usr/bin/env python3
 # Copyright 2015 gRPC authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
--- a/test/cpp/naming/utils/tcp_connect.py
+++ b/test/cpp/naming/utils/tcp_connect.py
@ -1,4 +1,4 @@
-#!/usr/bin/env python2.7
+#!/usr/bin/env python3
 # Copyright 2015 gRPC authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
--- a/test/cpp/util/BUILD
+++ b/test/cpp/util/BUILD
@ -423,3 +423,19 @@ grpc_cc_test(
        ":test_util",
    ],
 )
+
+grpc_cc_library(
+    name = "get_grpc_test_runfile_dir",
+    srcs = [
+        "get_grpc_test_runfile_dir.cc",
+    ],
+    hdrs = [
+        "get_grpc_test_runfile_dir.h",
+    ],
+    external_deps = [
+        "absl/types:optional",
+    ],
+    deps = [
+        "//src/core:env",
+    ],
+)
--- a/test/cpp/util/get_grpc_test_runfile_dir.cc
+++ b/test/cpp/util/get_grpc_test_runfile_dir.cc
@ -0,0 +1,29 @@
+// Copyright 2023 The 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 "test/cpp/util/get_grpc_test_runfile_dir.h"
+
+#include "src/core/lib/gprpp/env.h"
+
+namespace grpc {
+
+absl::optional<std::string> GetGrpcTestRunFileDir() {
+  absl::optional<std::string> test_srcdir = grpc_core::GetEnv("TEST_SRCDIR");
+  if (!test_srcdir.has_value()) {
+    return absl::nullopt;
+  }
+  return *test_srcdir + "/com_github_grpc_grpc";
+}
+
+}  // namespace grpc
--- a/test/cpp/util/get_grpc_test_runfile_dir.h
+++ b/test/cpp/util/get_grpc_test_runfile_dir.h
@ -0,0 +1,32 @@
+// Copyright 2023 The 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_TEST_CPP_UTIL_GET_GRPC_TEST_RUNFILE_DIR_H
+#define GRPC_TEST_CPP_UTIL_GET_GRPC_TEST_RUNFILE_DIR_H
+
+#include <string>
+
+#include "absl/types/optional.h"
+
+namespace grpc {
+
+// Gets the absolute path of the runfile directory (a bazel/blaze concept) for a
+// gRPC test. The path to the data files can be referred by joining the runfile
+// directory with the workspace-relative path (e.g.
+// "test/cpp/util/get_grpc_test_runfile_dir.h").
+absl::optional<std::string> GetGrpcTestRunFileDir();
+
+}  // namespace grpc
+
+#endif  // GRPC_TEST_CPP_UTIL_GET_GRPC_TEST_RUNFILE_DIR_H
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@ -2060,6 +2060,8 @@ src/core/lib/debug/stats_data.cc \
 src/core/lib/debug/stats_data.h \
 src/core/lib/debug/trace.cc \
 src/core/lib/debug/trace.h \
+src/core/lib/event_engine/ares_resolver.cc \
+src/core/lib/event_engine/ares_resolver.h \
 src/core/lib/event_engine/cf_engine/cf_engine.cc \
 src/core/lib/event_engine/cf_engine/cf_engine.h \
 src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc \
@ -2075,6 +2077,7 @@ src/core/lib/event_engine/default_event_engine_factory.h \
 src/core/lib/event_engine/event_engine.cc \
 src/core/lib/event_engine/forkable.cc \
 src/core/lib/event_engine/forkable.h \
+src/core/lib/event_engine/grpc_polled_fd.h \
 src/core/lib/event_engine/handle_containers.h \
 src/core/lib/event_engine/memory_allocator.cc \
 src/core/lib/event_engine/memory_allocator_factory.h \
@ -2087,6 +2090,7 @@ src/core/lib/event_engine/posix_engine/ev_poll_posix.h \
 src/core/lib/event_engine/posix_engine/event_poller.h \
 src/core/lib/event_engine/posix_engine/event_poller_posix_default.cc \
 src/core/lib/event_engine/posix_engine/event_poller_posix_default.h \
+src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h \
 src/core/lib/event_engine/posix_engine/internal_errqueue.cc \
 src/core/lib/event_engine/posix_engine/internal_errqueue.h \
 src/core/lib/event_engine/posix_engine/lockfree_event.cc \
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@ -1838,6 +1838,8 @@ src/core/lib/debug/stats_data.cc \
 src/core/lib/debug/stats_data.h \
 src/core/lib/debug/trace.cc \
 src/core/lib/debug/trace.h \
+src/core/lib/event_engine/ares_resolver.cc \
+src/core/lib/event_engine/ares_resolver.h \
 src/core/lib/event_engine/cf_engine/cf_engine.cc \
 src/core/lib/event_engine/cf_engine/cf_engine.h \
 src/core/lib/event_engine/cf_engine/cfstream_endpoint.cc \
@ -1853,6 +1855,7 @@ src/core/lib/event_engine/default_event_engine_factory.h \
 src/core/lib/event_engine/event_engine.cc \
 src/core/lib/event_engine/forkable.cc \
 src/core/lib/event_engine/forkable.h \
+src/core/lib/event_engine/grpc_polled_fd.h \
 src/core/lib/event_engine/handle_containers.h \
 src/core/lib/event_engine/memory_allocator.cc \
 src/core/lib/event_engine/memory_allocator_factory.h \
@ -1865,6 +1868,7 @@ src/core/lib/event_engine/posix_engine/ev_poll_posix.h \
 src/core/lib/event_engine/posix_engine/event_poller.h \
 src/core/lib/event_engine/posix_engine/event_poller_posix_default.cc \
 src/core/lib/event_engine/posix_engine/event_poller_posix_default.h \
+src/core/lib/event_engine/posix_engine/grpc_polled_fd_posix.h \
 src/core/lib/event_engine/posix_engine/internal_errqueue.cc \
 src/core/lib/event_engine/posix_engine/internal_errqueue.h \
 src/core/lib/event_engine/posix_engine/lockfree_event.cc \