Merge github.com:grpc/grpc into hybrid

11 files changed, 453 insertions, 165 deletions

diff --git a/test/core/client_channel/parse_address_test.c b/test/core/client_channel/parse_address_test.c
index 629cdb001f..802e41e5de 100644
--- a/test/core/client_channel/parse_address_test.c
+++ b/test/core/client_channel/parse_address_test.c
@@ -47,12 +47,12 @@
 
 #ifdef GRPC_HAVE_UNIX_SOCKET
 
-static void test_parse_unix(const char *uri_text, const char *pathname) {
+static void test_grpc_parse_unix(const char *uri_text, const char *pathname) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_uri *uri = grpc_uri_parse(&exec_ctx, uri_text, 0);
   grpc_resolved_address addr;
 
-  GPR_ASSERT(1 == parse_unix(uri, &addr));
+  GPR_ASSERT(1 == grpc_parse_unix(uri, &addr));
   struct sockaddr_un *addr_un = (struct sockaddr_un *)addr.addr;
   GPR_ASSERT(AF_UNIX == addr_un->sun_family);
   GPR_ASSERT(0 == strcmp(addr_un->sun_path, pathname));
@@ -63,18 +63,18 @@ static void test_parse_unix(const char *uri_text, const char *pathname) {
 
 #else /* GRPC_HAVE_UNIX_SOCKET */
 
-static void test_parse_unix(const char *uri_text, const char *pathname) {}
+static void test_grpc_parse_unix(const char *uri_text, const char *pathname) {}
 
 #endif /* GRPC_HAVE_UNIX_SOCKET */
 
-static void test_parse_ipv4(const char *uri_text, const char *host,
-                            unsigned short port) {
+static void test_grpc_parse_ipv4(const char *uri_text, const char *host,
+                                 unsigned short port) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_uri *uri = grpc_uri_parse(&exec_ctx, uri_text, 0);
   grpc_resolved_address addr;
   char ntop_buf[INET_ADDRSTRLEN];
 
-  GPR_ASSERT(1 == parse_ipv4(uri, &addr));
+  GPR_ASSERT(1 == grpc_parse_ipv4(uri, &addr));
   struct sockaddr_in *addr_in = (struct sockaddr_in *)addr.addr;
   GPR_ASSERT(AF_INET == addr_in->sin_family);
   GPR_ASSERT(NULL != grpc_inet_ntop(AF_INET, &addr_in->sin_addr, ntop_buf,
@@ -86,14 +86,14 @@ static void test_parse_ipv4(const char *uri_text, const char *host,
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
-static void test_parse_ipv6(const char *uri_text, const char *host,
-                            unsigned short port, uint32_t scope_id) {
+static void test_grpc_parse_ipv6(const char *uri_text, const char *host,
+                                 unsigned short port, uint32_t scope_id) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_uri *uri = grpc_uri_parse(&exec_ctx, uri_text, 0);
   grpc_resolved_address addr;
   char ntop_buf[INET6_ADDRSTRLEN];
 
-  GPR_ASSERT(1 == parse_ipv6(uri, &addr));
+  GPR_ASSERT(1 == grpc_parse_ipv6(uri, &addr));
   struct sockaddr_in6 *addr_in6 = (struct sockaddr_in6 *)addr.addr;
   GPR_ASSERT(AF_INET6 == addr_in6->sin6_family);
   GPR_ASSERT(NULL != grpc_inet_ntop(AF_INET6, &addr_in6->sin6_addr, ntop_buf,
@@ -109,8 +109,8 @@ static void test_parse_ipv6(const char *uri_text, const char *host,
 int main(int argc, char **argv) {
   grpc_test_init(argc, argv);
 
-  test_parse_unix("unix:/path/name", "/path/name");
-  test_parse_ipv4("ipv4:192.0.2.1:12345", "192.0.2.1", 12345);
-  test_parse_ipv6("ipv6:[2001:db8::1]:12345", "2001:db8::1", 12345, 0);
-  test_parse_ipv6("ipv6:[2001:db8::1%252]:12345", "2001:db8::1", 12345, 2);
+  test_grpc_parse_unix("unix:/path/name", "/path/name");
+  test_grpc_parse_ipv4("ipv4:192.0.2.1:12345", "192.0.2.1", 12345);
+  test_grpc_parse_ipv6("ipv6:[2001:db8::1]:12345", "2001:db8::1", 12345, 0);
+  test_grpc_parse_ipv6("ipv6:[2001:db8::1%252]:12345", "2001:db8::1", 12345, 2);
 }
diff --git a/test/core/client_channel/resolvers/BUILD b/test/core/client_channel/resolvers/BUILD
index af37072e3a..e8361cdef6 100644
--- a/test/core/client_channel/resolvers/BUILD
+++ b/test/core/client_channel/resolvers/BUILD
@@ -32,20 +32,48 @@ licenses(["notice"])  # 3-clause BSD
 cc_test(
     name = "dns_resolver_connectivity_test",
     srcs = ["dns_resolver_connectivity_test.c"],
-    deps = ["//:grpc", "//test/core/util:grpc_test_util", "//:gpr", "//test/core/util:gpr_test_util"],
-    copts = ['-std=c99']
+    copts = ["-std=c99"],
+    deps = [
+        "//:gpr",
+        "//:grpc",
+        "//test/core/util:gpr_test_util",
+        "//test/core/util:grpc_test_util",
+    ],
 )
 
 cc_test(
     name = "dns_resolver_test",
     srcs = ["dns_resolver_test.c"],
-    deps = ["//:grpc", "//test/core/util:grpc_test_util", "//:gpr", "//test/core/util:gpr_test_util"],
-    copts = ['-std=c99']
+    copts = ["-std=c99"],
+    deps = [
+        "//:gpr",
+        "//:grpc",
+        "//test/core/util:gpr_test_util",
+        "//test/core/util:grpc_test_util",
+    ],
 )
 
 cc_test(
     name = "sockaddr_resolver_test",
     srcs = ["sockaddr_resolver_test.c"],
-    deps = ["//:grpc", "//test/core/util:grpc_test_util", "//:gpr", "//test/core/util:gpr_test_util"],
-    copts = ['-std=c99']
+    copts = ["-std=c99"],
+    deps = [
+        "//:gpr",
+        "//:grpc",
+        "//test/core/util:gpr_test_util",
+        "//test/core/util:grpc_test_util",
+    ],
+)
+
+cc_test(
+    name = "fake_resolver_test",
+    srcs = ["fake_resolver_test.c"],
+    copts = ["-std=c99"],
+    deps = [
+        "//:gpr",
+        "//:grpc",
+        "//test/core/end2end:fake_resolver",
+        "//test/core/util:gpr_test_util",
+        "//test/core/util:grpc_test_util",
+    ],
 )
diff --git a/test/core/client_channel/resolvers/fake_resolver_test.c b/test/core/client_channel/resolvers/fake_resolver_test.c
new file mode 100644
index 0000000000..861918fbd6
--- /dev/null
+++ b/test/core/client_channel/resolvers/fake_resolver_test.c
@@ -0,0 +1,187 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include "src/core/ext/filters/client_channel/parse_address.h"
+#include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/combiner.h"
+#include "src/core/lib/security/credentials/fake/fake_credentials.h"
+
+#include "test/core/end2end/fake_resolver.h"
+#include "test/core/util/test_config.h"
+
+static grpc_resolver *build_fake_resolver(
+    grpc_exec_ctx *exec_ctx, grpc_combiner *combiner,
+    grpc_fake_resolver_response_generator *response_generator) {
+  grpc_resolver_factory *factory = grpc_resolver_factory_lookup("test");
+  grpc_arg generator_arg =
+      grpc_fake_resolver_response_generator_arg(response_generator);
+  grpc_resolver_args args;
+  memset(&args, 0, sizeof(args));
+  grpc_channel_args channel_args = {1, &generator_arg};
+  args.args = &channel_args;
+  args.combiner = combiner;
+  grpc_resolver *resolver =
+      grpc_resolver_factory_create_resolver(exec_ctx, factory, &args);
+  grpc_resolver_factory_unref(factory);
+  return resolver;
+}
+
+typedef struct on_resolution_arg {
+  grpc_channel_args *resolver_result;
+  grpc_channel_args *expected_resolver_result;
+  bool was_called;
+} on_resolution_arg;
+
+void on_resolution_cb(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
+  on_resolution_arg *res = arg;
+  res->was_called = true;
+  // We only check the addresses channel arg because that's the only one
+  // explicitly set by the test via
+  // grpc_fake_resolver_response_generator_set_response.
+  const grpc_lb_addresses *actual_lb_addresses =
+      grpc_lb_addresses_find_channel_arg(res->resolver_result);
+  const grpc_lb_addresses *expected_lb_addresses =
+      grpc_lb_addresses_find_channel_arg(res->expected_resolver_result);
+  GPR_ASSERT(
+      grpc_lb_addresses_cmp(actual_lb_addresses, expected_lb_addresses) == 0);
+  grpc_channel_args_destroy(exec_ctx, res->resolver_result);
+  grpc_channel_args_destroy(exec_ctx, res->expected_resolver_result);
+}
+
+static void test_fake_resolver() {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_combiner *combiner = grpc_combiner_create(NULL);
+  // Create resolver.
+  grpc_fake_resolver_response_generator *response_generator =
+      grpc_fake_resolver_response_generator_create();
+  grpc_resolver *resolver =
+      build_fake_resolver(&exec_ctx, combiner, response_generator);
+  GPR_ASSERT(resolver != NULL);
+
+  // Setup expectations.
+  grpc_uri *uris[] = {grpc_uri_parse(&exec_ctx, "ipv4:10.2.1.1:1234", true),
+                      grpc_uri_parse(&exec_ctx, "ipv4:127.0.0.1:4321", true)};
+  char *balancer_names[] = {"name1", "name2"};
+  const bool is_balancer[] = {true, false};
+  grpc_lb_addresses *addresses = grpc_lb_addresses_create(3, NULL);
+  for (size_t i = 0; i < GPR_ARRAY_SIZE(uris); ++i) {
+    grpc_lb_addresses_set_address_from_uri(
+        addresses, i, uris[i], is_balancer[i], balancer_names[i], NULL);
+    grpc_uri_destroy(uris[i]);
+  }
+  const grpc_arg addresses_arg =
+      grpc_lb_addresses_create_channel_arg(addresses);
+  grpc_channel_args *results =
+      grpc_channel_args_copy_and_add(NULL, &addresses_arg, 1);
+  grpc_lb_addresses_destroy(&exec_ctx, addresses);
+  on_resolution_arg on_res_arg;
+  memset(&on_res_arg, 0, sizeof(on_res_arg));
+  on_res_arg.expected_resolver_result = results;
+  grpc_closure *on_resolution = grpc_closure_create(
+      on_resolution_cb, &on_res_arg, grpc_combiner_scheduler(combiner, false));
+
+  // Set resolver results and trigger first resolution. on_resolution_cb
+  // performs the checks.
+  grpc_fake_resolver_response_generator_set_response(
+      &exec_ctx, response_generator, results);
+  grpc_resolver_next_locked(&exec_ctx, resolver, &on_res_arg.resolver_result,
+                            on_resolution);
+  grpc_exec_ctx_flush(&exec_ctx);
+  GPR_ASSERT(on_res_arg.was_called);
+
+  // Setup update.
+  grpc_uri *uris_update[] = {
+      grpc_uri_parse(&exec_ctx, "ipv4:192.168.1.0:31416", true)};
+  char *balancer_names_update[] = {"name3"};
+  const bool is_balancer_update[] = {false};
+  grpc_lb_addresses *addresses_update = grpc_lb_addresses_create(1, NULL);
+  for (size_t i = 0; i < GPR_ARRAY_SIZE(uris_update); ++i) {
+    grpc_lb_addresses_set_address_from_uri(addresses_update, i, uris_update[i],
+                                           is_balancer_update[i],
+                                           balancer_names_update[i], NULL);
+    grpc_uri_destroy(uris_update[i]);
+  }
+
+  grpc_arg addresses_update_arg =
+      grpc_lb_addresses_create_channel_arg(addresses_update);
+  grpc_channel_args *results_update =
+      grpc_channel_args_copy_and_add(NULL, &addresses_update_arg, 1);
+  grpc_lb_addresses_destroy(&exec_ctx, addresses_update);
+
+  // Setup expectations for the update.
+  on_resolution_arg on_res_arg_update;
+  memset(&on_res_arg_update, 0, sizeof(on_res_arg_update));
+  on_res_arg_update.expected_resolver_result = results_update;
+  on_resolution = grpc_closure_create(on_resolution_cb, &on_res_arg_update,
+                                      grpc_combiner_scheduler(combiner, false));
+
+  // Set updated resolver results and trigger a second resolution.
+  grpc_fake_resolver_response_generator_set_response(
+      &exec_ctx, response_generator, results_update);
+  grpc_resolver_next_locked(&exec_ctx, resolver,
+                            &on_res_arg_update.resolver_result, on_resolution);
+  grpc_exec_ctx_flush(&exec_ctx);
+  GPR_ASSERT(on_res_arg.was_called);
+
+  // Requesting a new resolution without re-senting the response shouldn't
+  // trigger the resolution callback.
+  memset(&on_res_arg, 0, sizeof(on_res_arg));
+  grpc_resolver_next_locked(&exec_ctx, resolver, &on_res_arg.resolver_result,
+                            on_resolution);
+  grpc_exec_ctx_flush(&exec_ctx);
+  GPR_ASSERT(!on_res_arg.was_called);
+
+  GRPC_COMBINER_UNREF(&exec_ctx, combiner, "test_fake_resolver");
+  GRPC_RESOLVER_UNREF(&exec_ctx, resolver, "test_fake_resolver");
+  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_fake_resolver_response_generator_unref(response_generator);
+}
+
+int main(int argc, char **argv) {
+  grpc_test_init(argc, argv);
+  grpc_fake_resolver_init();  // Registers the "test" scheme.
+  grpc_init();
+
+  test_fake_resolver();
+
+  grpc_shutdown();
+  return 0;
+}
diff --git a/test/core/end2end/BUILD b/test/core/end2end/BUILD
index 0cef7aa01d..ffea1cc4e8 100644
--- a/test/core/end2end/BUILD
+++ b/test/core/end2end/BUILD
@@ -32,49 +32,66 @@ licenses(["notice"])  # 3-clause BSD
 load(":generate_tests.bzl", "grpc_end2end_tests")
 
 cc_library(
-  name = 'cq_verifier',
-  srcs = ['cq_verifier.c'],
-  hdrs = ['cq_verifier.h'],
-  deps = ['//:gpr', '//:grpc', '//test/core/util:grpc_test_util'],
-  copts = ['-std=c99'],
-  visibility = ["//test:__subpackages__"],
+    name = "cq_verifier",
+    srcs = ["cq_verifier.c"],
+    hdrs = ["cq_verifier.h"],
+    copts = ["-std=c99"],
+    visibility = ["//test:__subpackages__"],
+    deps = [
+        "//:gpr",
+        "//:grpc",
+        "//test/core/util:grpc_test_util",
+    ],
 )
 
 cc_library(
-  name = 'ssl_test_data',
-  visibility = ["//test:__subpackages__"],
-  hdrs = ['data/ssl_test_data.h'],
-  copts = ['-std=c99'],
-  srcs = [
-    "data/client_certs.c",
-    "data/server1_cert.c",
-    "data/server1_key.c",
-    "data/test_root_cert.c",
-  ]
+    name = "ssl_test_data",
+    srcs = [
+        "data/client_certs.c",
+        "data/server1_cert.c",
+        "data/server1_key.c",
+        "data/test_root_cert.c",
+    ],
+    hdrs = ["data/ssl_test_data.h"],
+    copts = ["-std=c99"],
+    visibility = ["//test:__subpackages__"],
 )
 
 cc_library(
-  name = 'fake_resolver',
-  hdrs = ['fake_resolver.h'],
-  srcs = ['fake_resolver.c'],
-  copts = ['-std=c99'],
-  deps = ['//:gpr', '//:grpc', '//test/core/util:grpc_test_util']
+    name = "fake_resolver",
+    srcs = ["fake_resolver.c"],
+    hdrs = ["fake_resolver.h"],
+    copts = ["-std=c99"],
+    visibility = ["//test:__subpackages__"],
+    deps = [
+        "//:gpr",
+        "//:grpc",
+        "//test/core/util:grpc_test_util",
+    ],
 )
 
 cc_library(
-  name = 'http_proxy',
-  hdrs = ['fixtures/http_proxy_fixture.h'],
-  srcs = ['fixtures/http_proxy_fixture.c'],
-  copts = ['-std=c99'],
-  deps = ['//:gpr', '//:grpc', '//test/core/util:grpc_test_util']
+    name = "http_proxy",
+    srcs = ["fixtures/http_proxy_fixture.c"],
+    hdrs = ["fixtures/http_proxy_fixture.h"],
+    copts = ["-std=c99"],
+    deps = [
+        "//:gpr",
+        "//:grpc",
+        "//test/core/util:grpc_test_util",
+    ],
 )
 
 cc_library(
-  name = 'proxy',
-  hdrs = ['fixtures/proxy.h'],
-  srcs = ['fixtures/proxy.c'],
-  copts = ['-std=c99'],
-  deps = ['//:gpr', '//:grpc', '//test/core/util:grpc_test_util']
+    name = "proxy",
+    srcs = ["fixtures/proxy.c"],
+    hdrs = ["fixtures/proxy.h"],
+    copts = ["-std=c99"],
+    deps = [
+        "//:gpr",
+        "//:grpc",
+        "//test/core/util:grpc_test_util",
+    ],
 )
 
 grpc_end2end_tests()
diff --git a/test/core/end2end/fake_resolver.c b/test/core/end2end/fake_resolver.c
index 1c7dd1339c..6a71c20b80 100644
--- a/test/core/end2end/fake_resolver.c
+++ b/test/core/end2end/fake_resolver.c
@@ -32,6 +32,7 @@
 // This is similar to the sockaddr resolver, except that it supports a
 // bunch of query args that are useful for dependency injection in tests.
 
+#include <limits.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -46,12 +47,18 @@
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 
+#include "test/core/end2end/fake_resolver.h"
+
+#define GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR \
+  "grpc.fake_resolver.response_generator"
+
 //
 // fake_resolver
 //
@@ -62,12 +69,11 @@ typedef struct {
 
   // passed-in parameters
   grpc_channel_args* channel_args;
-  grpc_lb_addresses* addresses;
 
-  // mutex guarding the rest of the state
-  gpr_mu mu;
-  // have we published?
-  bool published;
+  // If not NULL, the next set of resolution results to be returned to
+  // grpc_resolver_next_locked()'s closure.
+  grpc_channel_args* next_results;
+
   // pending next completion, or NULL
   grpc_closure* next_completion;
   // target result address for next completion
@@ -76,60 +82,137 @@ typedef struct {
 
 static void fake_resolver_destroy(grpc_exec_ctx* exec_ctx, grpc_resolver* gr) {
   fake_resolver* r = (fake_resolver*)gr;
-  gpr_mu_destroy(&r->mu);
+  grpc_channel_args_destroy(exec_ctx, r->next_results);
   grpc_channel_args_destroy(exec_ctx, r->channel_args);
-  grpc_lb_addresses_destroy(exec_ctx, r->addresses);
   gpr_free(r);
 }
 
-static void fake_resolver_shutdown(grpc_exec_ctx* exec_ctx,
-                                   grpc_resolver* resolver) {
+static void fake_resolver_shutdown_locked(grpc_exec_ctx* exec_ctx,
+                                          grpc_resolver* resolver) {
   fake_resolver* r = (fake_resolver*)resolver;
-  gpr_mu_lock(&r->mu);
   if (r->next_completion != NULL) {
     *r->target_result = NULL;
     grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
     r->next_completion = NULL;
   }
-  gpr_mu_unlock(&r->mu);
 }
 
 static void fake_resolver_maybe_finish_next_locked(grpc_exec_ctx* exec_ctx,
                                                    fake_resolver* r) {
-  if (r->next_completion != NULL && !r->published) {
-    r->published = true;
-    grpc_arg arg = grpc_lb_addresses_create_channel_arg(r->addresses);
+  if (r->next_completion != NULL && r->next_results != NULL) {
     *r->target_result =
-        grpc_channel_args_copy_and_add(r->channel_args, &arg, 1);
+        grpc_channel_args_merge(r->channel_args, r->next_results);
+    grpc_channel_args_destroy(exec_ctx, r->next_results);
     grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
     r->next_completion = NULL;
+    r->next_results = NULL;
   }
 }
 
-static void fake_resolver_channel_saw_error(grpc_exec_ctx* exec_ctx,
-                                            grpc_resolver* resolver) {
+static void fake_resolver_channel_saw_error_locked(grpc_exec_ctx* exec_ctx,
+                                                   grpc_resolver* resolver) {
   fake_resolver* r = (fake_resolver*)resolver;
-  gpr_mu_lock(&r->mu);
-  r->published = false;
   fake_resolver_maybe_finish_next_locked(exec_ctx, r);
-  gpr_mu_unlock(&r->mu);
 }
 
-static void fake_resolver_next(grpc_exec_ctx* exec_ctx, grpc_resolver* resolver,
-                               grpc_channel_args** target_result,
-                               grpc_closure* on_complete) {
+static void fake_resolver_next_locked(grpc_exec_ctx* exec_ctx,
+                                      grpc_resolver* resolver,
+                                      grpc_channel_args** target_result,
+                                      grpc_closure* on_complete) {
   fake_resolver* r = (fake_resolver*)resolver;
-  gpr_mu_lock(&r->mu);
   GPR_ASSERT(!r->next_completion);
   r->next_completion = on_complete;
   r->target_result = target_result;
   fake_resolver_maybe_finish_next_locked(exec_ctx, r);
-  gpr_mu_unlock(&r->mu);
 }
 
 static const grpc_resolver_vtable fake_resolver_vtable = {
-    fake_resolver_destroy, fake_resolver_shutdown,
-    fake_resolver_channel_saw_error, fake_resolver_next};
+    fake_resolver_destroy, fake_resolver_shutdown_locked,
+    fake_resolver_channel_saw_error_locked, fake_resolver_next_locked};
+
+struct grpc_fake_resolver_response_generator {
+  fake_resolver* resolver;  // Set by the fake_resolver constructor to itself.
+  grpc_channel_args* next_response;
+  gpr_refcount refcount;
+};
+
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_response_generator_create() {
+  grpc_fake_resolver_response_generator* generator =
+      gpr_zalloc(sizeof(*generator));
+  gpr_ref_init(&generator->refcount, 1);
+  return generator;
+}
+
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_response_generator_ref(
+    grpc_fake_resolver_response_generator* generator) {
+  gpr_ref(&generator->refcount);
+  return generator;
+}
+
+void grpc_fake_resolver_response_generator_unref(
+    grpc_fake_resolver_response_generator* generator) {
+  if (gpr_unref(&generator->refcount)) {
+    gpr_free(generator);
+  }
+}
+
+static void set_response_cb(grpc_exec_ctx* exec_ctx, void* arg,
+                            grpc_error* error) {
+  grpc_fake_resolver_response_generator* generator = arg;
+  fake_resolver* r = generator->resolver;
+  if (r->next_results != NULL) {
+    grpc_channel_args_destroy(exec_ctx, r->next_results);
+  }
+  r->next_results = generator->next_response;
+  fake_resolver_maybe_finish_next_locked(exec_ctx, r);
+}
+
+void grpc_fake_resolver_response_generator_set_response(
+    grpc_exec_ctx* exec_ctx, grpc_fake_resolver_response_generator* generator,
+    grpc_channel_args* next_response) {
+  GPR_ASSERT(generator->resolver != NULL);
+  generator->next_response = grpc_channel_args_copy(next_response);
+  grpc_closure_sched(
+      exec_ctx,
+      grpc_closure_create(
+          set_response_cb, generator,
+          grpc_combiner_scheduler(generator->resolver->base.combiner, false)),
+      GRPC_ERROR_NONE);
+}
+
+static void* response_generator_arg_copy(void* p) {
+  return grpc_fake_resolver_response_generator_ref(p);
+}
+
+static void response_generator_arg_destroy(grpc_exec_ctx* exec_ctx, void* p) {
+  grpc_fake_resolver_response_generator_unref(p);
+}
+
+static int response_generator_cmp(void* a, void* b) { return GPR_ICMP(a, b); }
+
+static const grpc_arg_pointer_vtable response_generator_arg_vtable = {
+    response_generator_arg_copy, response_generator_arg_destroy,
+    response_generator_cmp};
+
+grpc_arg grpc_fake_resolver_response_generator_arg(
+    grpc_fake_resolver_response_generator* generator) {
+  grpc_arg arg;
+  arg.type = GRPC_ARG_POINTER;
+  arg.key = GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR;
+  arg.value.pointer.p = generator;
+  arg.value.pointer.vtable = &response_generator_arg_vtable;
+  return arg;
+}
+
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_get_response_generator(const grpc_channel_args* args) {
+  const grpc_arg* arg =
+      grpc_channel_args_find(args, GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR);
+  if (arg == NULL || arg->type != GRPC_ARG_POINTER) return NULL;
+  return arg->value.pointer.p;
+}
 
 //
 // fake_resolver_factory
@@ -139,81 +222,15 @@ static void fake_resolver_factory_ref(grpc_resolver_factory* factory) {}
 
 static void fake_resolver_factory_unref(grpc_resolver_factory* factory) {}
 
-static void do_nothing(void* ignored) {}
-
 static grpc_resolver* fake_resolver_create(grpc_exec_ctx* exec_ctx,
                                            grpc_resolver_factory* factory,
                                            grpc_resolver_args* args) {
-  if (0 != strcmp(args->uri->authority, "")) {
-    gpr_log(GPR_ERROR, "authority based uri's not supported by the %s scheme",
-            args->uri->scheme);
-    return NULL;
-  }
-  // Get lb_enabled arg.  Anything other than "0" is interpreted as true.
-  const char* lb_enabled_qpart =
-      grpc_uri_get_query_arg(args->uri, "lb_enabled");
-  const bool lb_enabled =
-      lb_enabled_qpart != NULL && strcmp("0", lb_enabled_qpart) != 0;
-
-  // Get the balancer's names.
-  const char* balancer_names =
-      grpc_uri_get_query_arg(args->uri, "balancer_names");
-  grpc_slice_buffer balancer_names_parts;
-  grpc_slice_buffer_init(&balancer_names_parts);
-  if (balancer_names != NULL) {
-    const grpc_slice balancer_names_slice =
-        grpc_slice_from_copied_string(balancer_names);
-    grpc_slice_split(balancer_names_slice, ",", &balancer_names_parts);
-    grpc_slice_unref(balancer_names_slice);
-  }
-
-  // Construct addresses.
-  grpc_slice path_slice =
-      grpc_slice_new(args->uri->path, strlen(args->uri->path), do_nothing);
-  grpc_slice_buffer path_parts;
-  grpc_slice_buffer_init(&path_parts);
-  grpc_slice_split(path_slice, ",", &path_parts);
-  if (balancer_names_parts.count > 0 &&
-      path_parts.count != balancer_names_parts.count) {
-    gpr_log(GPR_ERROR,
-            "Balancer names present but mismatched with number of addresses: "
-            "%lu balancer names != %lu addresses",
-            (unsigned long)balancer_names_parts.count,
-            (unsigned long)path_parts.count);
-    return NULL;
-  }
-  grpc_lb_addresses* addresses =
-      grpc_lb_addresses_create(path_parts.count, NULL /* user_data_vtable */);
-  bool errors_found = false;
-  for (size_t i = 0; i < addresses->num_addresses; i++) {
-    grpc_uri ith_uri = *args->uri;
-    char* part_str = grpc_slice_to_c_string(path_parts.slices[i]);
-    ith_uri.path = part_str;
-    if (!parse_ipv4(&ith_uri, &addresses->addresses[i].address)) {
-      errors_found = true;
-    }
-    gpr_free(part_str);
-    if (errors_found) break;
-    addresses->addresses[i].is_balancer = lb_enabled;
-    addresses->addresses[i].balancer_name =
-        balancer_names_parts.count > 0
-            ? grpc_dump_slice(balancer_names_parts.slices[i], GPR_DUMP_ASCII)
-            : NULL;
-  }
-  grpc_slice_buffer_destroy_internal(exec_ctx, &path_parts);
-  grpc_slice_buffer_destroy_internal(exec_ctx, &balancer_names_parts);
-  grpc_slice_unref(path_slice);
-  if (errors_found) {
-    grpc_lb_addresses_destroy(exec_ctx, addresses);
-    return NULL;
-  }
-  // Instantiate resolver.
-  fake_resolver* r = gpr_malloc(sizeof(fake_resolver));
-  memset(r, 0, sizeof(*r));
+  fake_resolver* r = gpr_zalloc(sizeof(*r));
   r->channel_args = grpc_channel_args_copy(args->args);
-  r->addresses = addresses;
-  gpr_mu_init(&r->mu);
   grpc_resolver_init(&r->base, &fake_resolver_vtable, args->combiner);
+  grpc_fake_resolver_response_generator* response_generator =
+      grpc_fake_resolver_get_response_generator(args->args);
+  if (response_generator != NULL) response_generator->resolver = r;
   return &r->base;
 }
 
diff --git a/test/core/end2end/fake_resolver.h b/test/core/end2end/fake_resolver.h
index 7a30347f30..447289adef 100644
--- a/test/core/end2end/fake_resolver.h
+++ b/test/core/end2end/fake_resolver.h
@@ -32,8 +32,42 @@
 #ifndef GRPC_TEST_CORE_END2END_FAKE_RESOLVER_H
 #define GRPC_TEST_CORE_END2END_FAKE_RESOLVER_H
 
+#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include "src/core/ext/filters/client_channel/uri_parser.h"
+#include "src/core/lib/channel/channel_args.h"
+
 #include "test/core/util/test_config.h"
 
 void grpc_fake_resolver_init();
 
+// Instances of \a grpc_fake_resolver_response_generator are passed to the
+// fake resolver in a channel argument (see \a
+// grpc_fake_resolver_response_generator_arg) in order to inject and trigger
+// custom resolutions. See also \a
+// grpc_fake_resolver_response_generator_set_response.
+typedef struct grpc_fake_resolver_response_generator
+    grpc_fake_resolver_response_generator;
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_response_generator_create();
+
+// Instruct the fake resolver associated with the \a response_generator instance
+// to trigger a new resolution for \a uri and \a args.
+void grpc_fake_resolver_response_generator_set_response(
+    grpc_exec_ctx* exec_ctx, grpc_fake_resolver_response_generator* generator,
+    grpc_channel_args* next_response);
+
+// Return a \a grpc_arg for a \a grpc_fake_resolver_response_generator instance.
+grpc_arg grpc_fake_resolver_response_generator_arg(
+    grpc_fake_resolver_response_generator* generator);
+// Return the \a grpc_fake_resolver_response_generator instance in \a args or
+// NULL.
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_get_response_generator(const grpc_channel_args* args);
+
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_response_generator_ref(
+    grpc_fake_resolver_response_generator* generator);
+void grpc_fake_resolver_response_generator_unref(
+    grpc_fake_resolver_response_generator* generator);
+
 #endif /* GRPC_TEST_CORE_END2END_FAKE_RESOLVER_H */
diff --git a/test/core/end2end/fuzzers/api_fuzzer.c b/test/core/end2end/fuzzers/api_fuzzer.c
index 8b8983ee17..83c82ba5c0 100644
--- a/test/core/end2end/fuzzers/api_fuzzer.c
+++ b/test/core/end2end/fuzzers/api_fuzzer.c
@@ -932,6 +932,9 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         }
         uint32_t propagation_mask = read_uint32(&inp);
         grpc_slice method = read_string_like_slice(&inp);
+        if (GRPC_SLICE_LENGTH(method) == 0) {
+          ok = false;
+        }
         grpc_slice host = read_string_like_slice(&inp);
         gpr_timespec deadline =
             gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
diff --git a/test/core/end2end/fuzzers/api_fuzzer_corpus/clusterfuzz-testcase-5867145026076672 b/test/core/end2end/fuzzers/api_fuzzer_corpus/clusterfuzz-testcase-5867145026076672
new file mode 100644
index 0000000000..3fd5427b46
--- /dev/null
+++ b/test/core/end2end/fuzzers/api_fuzzer_corpus/clusterfuzz-testcase-5867145026076672
diff --git a/test/core/end2end/fuzzers/hpack.dictionary b/test/core/end2end/fuzzers/hpack.dictionary
index 4282c61214..2bb9de34c5 100644
--- a/test/core/end2end/fuzzers/hpack.dictionary
+++ b/test/core/end2end/fuzzers/hpack.dictionary
@@ -77,6 +77,7 @@
 "\x08if-range"
 "\x13if-unmodified-since"
 "\x0Dlast-modified"
+"\x0Blb-cost-bin"
 "\x04link"
 "\x08location"
 "\x0Cmax-forwards"
@@ -153,6 +154,7 @@
 "\x00\x13if-unmodified-since\x00"
 "\x00\x0Dlast-modified\x00"
 "\x00\x08lb-token\x00"
+"\x00\x0Blb-cost-bin\x00"
 "\x00\x04link\x00"
 "\x00\x08location\x00"
 "\x00\x0Cmax-forwards\x00"
diff --git a/test/core/end2end/tests/load_reporting_hook.c b/test/core/end2end/tests/load_reporting_hook.c
index 72e9db6e21..c021bc07ff 100644
--- a/test/core/end2end/tests/load_reporting_hook.c
+++ b/test/core/end2end/tests/load_reporting_hook.c
@@ -129,8 +129,7 @@ static void end_test(grpc_end2end_test_fixture *f) {
 static void request_response_with_payload(
     grpc_end2end_test_config config, grpc_end2end_test_fixture f,
     const char *method_name, const char *request_msg, const char *response_msg,
-    grpc_metadata *initial_lr_metadata,
-    grpc_load_reporting_cost_context *cost_ctx) {
+    grpc_metadata *initial_lr_metadata, grpc_metadata *trailing_lr_metadata) {
   grpc_slice request_payload_slice = grpc_slice_from_static_string(request_msg);
   grpc_slice response_payload_slice =
       grpc_slice_from_static_string(response_msg);
@@ -243,8 +242,9 @@ static void request_response_with_payload(
   op->reserved = NULL;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
-  GPR_ASSERT(cost_ctx != NULL);
-  grpc_call_set_load_reporting_cost_context(s, cost_ctx);
+  GPR_ASSERT(trailing_lr_metadata != NULL);
+  op->data.send_status_from_server.trailing_metadata_count = 1;
+  op->data.send_status_from_server.trailing_metadata = trailing_lr_metadata;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
@@ -298,21 +298,21 @@ static void test_load_reporting_hook(grpc_end2end_test_config config) {
   const char *response_msg = "... and the response from the server";
 
   grpc_metadata initial_lr_metadata;
+  grpc_metadata trailing_lr_metadata;
 
   initial_lr_metadata.key = GRPC_MDSTR_LB_TOKEN;
   initial_lr_metadata.value = grpc_slice_from_static_string("client-token");
   memset(&initial_lr_metadata.internal_data, 0,
          sizeof(initial_lr_metadata.internal_data));
 
-  grpc_load_reporting_cost_context *cost_ctx = gpr_malloc(sizeof(*cost_ctx));
-  memset(cost_ctx, 0, sizeof(*cost_ctx));
-  cost_ctx->values_count = 1;
-  cost_ctx->values =
-      gpr_malloc(sizeof(*cost_ctx->values) * cost_ctx->values_count);
-  cost_ctx->values[0] = grpc_slice_from_static_string("cost-token");
+  trailing_lr_metadata.key = GRPC_MDSTR_LB_COST_BIN;
+  trailing_lr_metadata.value = grpc_slice_from_static_string("server-token");
+  memset(&trailing_lr_metadata.internal_data, 0,
+         sizeof(trailing_lr_metadata.internal_data));
 
   request_response_with_payload(config, f, method_name, request_msg,
-                                response_msg, &initial_lr_metadata, cost_ctx);
+                                response_msg, &initial_lr_metadata,
+                                &trailing_lr_metadata);
   end_test(&f);
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
diff --git a/test/core/iomgr/udp_server_test.c b/test/core/iomgr/udp_server_test.c
index 12d8406323..1f1696a7a7 100644
--- a/test/core/iomgr/udp_server_test.c
+++ b/test/core/iomgr/udp_server_test.c
@@ -91,7 +91,7 @@ static void on_write(grpc_exec_ctx *exec_ctx, grpc_fd *emfd, void *user_data) {
 }
 
 static void on_fd_orphaned(grpc_exec_ctx *exec_ctx, grpc_fd *emfd,
-                           void *user_data) {
+                           grpc_closure *closure, void *user_data) {
   gpr_log(GPR_INFO, "gRPC FD about to be orphaned: %d",
           grpc_fd_wrapped_fd(emfd));
   g_number_of_orphan_calls++;
@@ -228,9 +228,9 @@ static void test_no_op_with_port_and_start(void) {
   grpc_udp_server_destroy(&exec_ctx, s, NULL);
   grpc_exec_ctx_finish(&exec_ctx);
 
-  /* The server had a single FD, which is orphaned once in *
-   * deactivated_all_ports, and once in grpc_udp_server_destroy. */
-  GPR_ASSERT(g_number_of_orphan_calls == 2);
+  /* The server had a single FD, which is orphaned exactly once in *
+   * grpc_udp_server_destroy. */
+  GPR_ASSERT(g_number_of_orphan_calls == 1);
 }
 
 static void test_receive(int number_of_clients) {
@@ -297,9 +297,9 @@ static void test_receive(int number_of_clients) {
   grpc_udp_server_destroy(&exec_ctx, s, NULL);
   grpc_exec_ctx_finish(&exec_ctx);
 
-  /* The server had a single FD, which is orphaned once in *
-   * deactivated_all_ports, and once in grpc_udp_server_destroy. */
-  GPR_ASSERT(g_number_of_orphan_calls == 2);
+  /* The server had a single FD, which is orphaned exactly once in *
+   * grpc_udp_server_destroy. */
+  GPR_ASSERT(g_number_of_orphan_calls == 1);
 
   /* The write callback should have fired a few times. */
   GPR_ASSERT(g_number_of_writes > 0);