| /* |
| * |
| * Copyright 2016 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> |
| #if GRPC_ARES == 1 && !defined(GRPC_UV) |
| |
| #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h" |
| #include "src/core/lib/iomgr/sockaddr.h" |
| #include "src/core/lib/iomgr/socket_utils_posix.h" |
| |
| #include <string.h> |
| #include <sys/types.h> |
| |
| #include <ares.h> |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/log.h> |
| #include <grpc/support/string_util.h> |
| #include <grpc/support/time.h> |
| |
| #include "src/core/ext/filters/client_channel/parse_address.h" |
| #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h" |
| #include "src/core/lib/gpr/host_port.h" |
| #include "src/core/lib/gpr/string.h" |
| #include "src/core/lib/iomgr/error.h" |
| #include "src/core/lib/iomgr/executor.h" |
| #include "src/core/lib/iomgr/iomgr_internal.h" |
| #include "src/core/lib/iomgr/nameser.h" |
| #include "src/core/lib/iomgr/sockaddr_utils.h" |
| |
| static gpr_once g_basic_init = GPR_ONCE_INIT; |
| static gpr_mu g_init_mu; |
| |
| struct grpc_ares_request { |
| /** indicates the DNS server to use, if specified */ |
| struct ares_addr_port_node dns_server_addr; |
| /** following members are set in grpc_resolve_address_ares_impl */ |
| /** closure to call when the request completes */ |
| grpc_closure* on_done; |
| /** the pointer to receive the resolved addresses */ |
| grpc_lb_addresses** lb_addrs_out; |
| /** the pointer to receive the service config in JSON */ |
| char** service_config_json_out; |
| /** the evernt driver used by this request */ |
| grpc_ares_ev_driver* ev_driver; |
| /** number of ongoing queries */ |
| gpr_refcount pending_queries; |
| |
| /** mutex guarding the rest of the state */ |
| gpr_mu mu; |
| /** is there at least one successful query, set in on_done_cb */ |
| bool success; |
| /** the errors explaining the request failure, set in on_done_cb */ |
| grpc_error* error; |
| }; |
| |
| typedef struct grpc_ares_hostbyname_request { |
| /** following members are set in create_hostbyname_request */ |
| /** the top-level request instance */ |
| grpc_ares_request* parent_request; |
| /** host to resolve, parsed from the name to resolve */ |
| char* host; |
| /** port to fill in sockaddr_in, parsed from the name to resolve */ |
| uint16_t port; |
| /** is it a grpclb address */ |
| bool is_balancer; |
| } grpc_ares_hostbyname_request; |
| |
| static void do_basic_init(void) { gpr_mu_init(&g_init_mu); } |
| |
| static uint16_t strhtons(const char* port) { |
| if (strcmp(port, "http") == 0) { |
| return htons(80); |
| } else if (strcmp(port, "https") == 0) { |
| return htons(443); |
| } |
| return htons(static_cast<unsigned short>(atoi(port))); |
| } |
| |
| static void grpc_ares_request_ref(grpc_ares_request* r) { |
| gpr_ref(&r->pending_queries); |
| } |
| |
| static void grpc_ares_request_unref(grpc_ares_request* r) { |
| /* If there are no pending queries, invoke on_done callback and destroy the |
| request */ |
| if (gpr_unref(&r->pending_queries)) { |
| /* TODO(zyc): Sort results with RFC6724 before invoking on_done. */ |
| GRPC_CLOSURE_SCHED(r->on_done, r->error); |
| gpr_mu_destroy(&r->mu); |
| grpc_ares_ev_driver_destroy(r->ev_driver); |
| gpr_free(r); |
| } |
| } |
| |
| static grpc_ares_hostbyname_request* create_hostbyname_request( |
| grpc_ares_request* parent_request, char* host, uint16_t port, |
| bool is_balancer) { |
| grpc_ares_hostbyname_request* hr = static_cast<grpc_ares_hostbyname_request*>(gpr_zalloc( |
| sizeof(grpc_ares_hostbyname_request))); |
| hr->parent_request = parent_request; |
| hr->host = gpr_strdup(host); |
| hr->port = port; |
| hr->is_balancer = is_balancer; |
| grpc_ares_request_ref(parent_request); |
| return hr; |
| } |
| |
| static void destroy_hostbyname_request(grpc_ares_hostbyname_request* hr) { |
| grpc_ares_request_unref(hr->parent_request); |
| gpr_free(hr->host); |
| gpr_free(hr); |
| } |
| |
| static void on_hostbyname_done_cb(void* arg, int status, int timeouts, |
| struct hostent* hostent) { |
| grpc_ares_hostbyname_request* hr = static_cast<grpc_ares_hostbyname_request*>(arg); |
| grpc_ares_request* r = hr->parent_request; |
| gpr_mu_lock(&r->mu); |
| if (status == ARES_SUCCESS) { |
| GRPC_ERROR_UNREF(r->error); |
| r->error = GRPC_ERROR_NONE; |
| r->success = true; |
| grpc_lb_addresses** lb_addresses = r->lb_addrs_out; |
| if (*lb_addresses == nullptr) { |
| *lb_addresses = grpc_lb_addresses_create(0, nullptr); |
| } |
| size_t prev_naddr = (*lb_addresses)->num_addresses; |
| size_t i; |
| for (i = 0; hostent->h_addr_list[i] != nullptr; i++) { |
| } |
| (*lb_addresses)->num_addresses += i; |
| (*lb_addresses)->addresses = static_cast<grpc_lb_address*>(gpr_realloc( |
| (*lb_addresses)->addresses, |
| sizeof(grpc_lb_address) * (*lb_addresses)->num_addresses)); |
| for (i = prev_naddr; i < (*lb_addresses)->num_addresses; i++) { |
| switch (hostent->h_addrtype) { |
| case AF_INET6: { |
| size_t addr_len = sizeof(struct sockaddr_in6); |
| struct sockaddr_in6 addr; |
| memset(&addr, 0, addr_len); |
| memcpy(&addr.sin6_addr, hostent->h_addr_list[i - prev_naddr], |
| sizeof(struct in6_addr)); |
| addr.sin6_family = static_cast<sa_family_t>(hostent->h_addrtype); |
| addr.sin6_port = hr->port; |
| grpc_lb_addresses_set_address( |
| *lb_addresses, i, &addr, addr_len, |
| hr->is_balancer /* is_balancer */, |
| hr->is_balancer ? hr->host : nullptr /* balancer_name */, |
| nullptr /* user_data */); |
| char output[INET6_ADDRSTRLEN]; |
| ares_inet_ntop(AF_INET6, &addr.sin6_addr, output, INET6_ADDRSTRLEN); |
| gpr_log(GPR_DEBUG, |
| "c-ares resolver gets a AF_INET6 result: \n" |
| " addr: %s\n port: %d\n sin6_scope_id: %d\n", |
| output, ntohs(hr->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 - prev_naddr], |
| sizeof(struct in_addr)); |
| addr.sin_family = static_cast<sa_family_t>(hostent->h_addrtype); |
| addr.sin_port = hr->port; |
| grpc_lb_addresses_set_address( |
| *lb_addresses, i, &addr, addr_len, |
| hr->is_balancer /* is_balancer */, |
| hr->is_balancer ? hr->host : nullptr /* balancer_name */, |
| nullptr /* user_data */); |
| char output[INET_ADDRSTRLEN]; |
| ares_inet_ntop(AF_INET, &addr.sin_addr, output, INET_ADDRSTRLEN); |
| gpr_log(GPR_DEBUG, |
| "c-ares resolver gets a AF_INET result: \n" |
| " addr: %s\n port: %d\n", |
| output, ntohs(hr->port)); |
| break; |
| } |
| } |
| } |
| } else if (!r->success) { |
| char* error_msg; |
| gpr_asprintf(&error_msg, "C-ares status is not ARES_SUCCESS: %s", |
| ares_strerror(status)); |
| grpc_error* error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_msg); |
| gpr_free(error_msg); |
| if (r->error == GRPC_ERROR_NONE) { |
| r->error = error; |
| } else { |
| r->error = grpc_error_add_child(error, r->error); |
| } |
| } |
| gpr_mu_unlock(&r->mu); |
| destroy_hostbyname_request(hr); |
| } |
| |
| static void on_srv_query_done_cb(void* arg, int status, int timeouts, |
| unsigned char* abuf, int alen) { |
| grpc_ares_request* r = static_cast<grpc_ares_request*>(arg); |
| grpc_core::ExecCtx exec_ctx; |
| gpr_log(GPR_DEBUG, "on_query_srv_done_cb"); |
| if (status == ARES_SUCCESS) { |
| gpr_log(GPR_DEBUG, "on_query_srv_done_cb ARES_SUCCESS"); |
| struct ares_srv_reply* reply; |
| const int parse_status = ares_parse_srv_reply(abuf, alen, &reply); |
| if (parse_status == ARES_SUCCESS) { |
| ares_channel* channel = grpc_ares_ev_driver_get_channel(r->ev_driver); |
| for (struct ares_srv_reply* srv_it = reply; srv_it != nullptr; |
| srv_it = srv_it->next) { |
| if (grpc_ipv6_loopback_available()) { |
| grpc_ares_hostbyname_request* hr = create_hostbyname_request( |
| r, srv_it->host, htons(srv_it->port), true /* is_balancer */); |
| ares_gethostbyname(*channel, hr->host, AF_INET6, |
| on_hostbyname_done_cb, hr); |
| } |
| grpc_ares_hostbyname_request* hr = create_hostbyname_request( |
| r, srv_it->host, htons(srv_it->port), true /* is_balancer */); |
| ares_gethostbyname(*channel, hr->host, AF_INET, on_hostbyname_done_cb, |
| hr); |
| grpc_ares_ev_driver_start(r->ev_driver); |
| } |
| } |
| if (reply != nullptr) { |
| ares_free_data(reply); |
| } |
| } else if (!r->success) { |
| char* error_msg; |
| gpr_asprintf(&error_msg, "C-ares status is not ARES_SUCCESS: %s", |
| ares_strerror(status)); |
| grpc_error* error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_msg); |
| gpr_free(error_msg); |
| if (r->error == GRPC_ERROR_NONE) { |
| r->error = error; |
| } else { |
| r->error = grpc_error_add_child(error, r->error); |
| } |
| } |
| grpc_ares_request_unref(r); |
| } |
| |
| static const char g_service_config_attribute_prefix[] = "grpc_config="; |
| |
| static void on_txt_done_cb(void* arg, int status, int timeouts, |
| unsigned char* buf, int len) { |
| gpr_log(GPR_DEBUG, "on_txt_done_cb"); |
| char* error_msg; |
| grpc_ares_request* r = static_cast<grpc_ares_request*>(arg); |
| const size_t prefix_len = sizeof(g_service_config_attribute_prefix) - 1; |
| struct ares_txt_ext* result = nullptr; |
| struct ares_txt_ext* reply = nullptr; |
| grpc_error* error = GRPC_ERROR_NONE; |
| gpr_mu_lock(&r->mu); |
| if (status != ARES_SUCCESS) goto fail; |
| status = ares_parse_txt_reply_ext(buf, len, &reply); |
| if (status != ARES_SUCCESS) goto fail; |
| // Find service config in TXT record. |
| for (result = reply; result != nullptr; result = result->next) { |
| if (result->record_start && |
| memcmp(result->txt, g_service_config_attribute_prefix, prefix_len) == |
| 0) { |
| break; |
| } |
| } |
| // Found a service config record. |
| if (result != nullptr) { |
| size_t service_config_len = result->length - prefix_len; |
| *r->service_config_json_out = static_cast<char*>(gpr_malloc(service_config_len + 1)); |
| memcpy(*r->service_config_json_out, result->txt + prefix_len, |
| service_config_len); |
| for (result = result->next; result != nullptr && !result->record_start; |
| result = result->next) { |
| *r->service_config_json_out = static_cast<char*>(gpr_realloc( |
| *r->service_config_json_out, service_config_len + result->length + 1)); |
| memcpy(*r->service_config_json_out + service_config_len, result->txt, |
| result->length); |
| service_config_len += result->length; |
| } |
| (*r->service_config_json_out)[service_config_len] = '\0'; |
| gpr_log(GPR_INFO, "found service config: %s", *r->service_config_json_out); |
| } |
| // Clean up. |
| ares_free_data(reply); |
| goto done; |
| fail: |
| gpr_asprintf(&error_msg, "C-ares TXT lookup status is not ARES_SUCCESS: %s", |
| ares_strerror(status)); |
| error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_msg); |
| gpr_free(error_msg); |
| if (r->error == GRPC_ERROR_NONE) { |
| r->error = error; |
| } else { |
| r->error = grpc_error_add_child(error, r->error); |
| } |
| done: |
| gpr_mu_unlock(&r->mu); |
| grpc_ares_request_unref(r); |
| } |
| |
| static grpc_ares_request* grpc_dns_lookup_ares_impl( |
| const char* dns_server, const char* name, const char* default_port, |
| grpc_pollset_set* interested_parties, grpc_closure* on_done, |
| grpc_lb_addresses** addrs, bool check_grpclb, char** service_config_json) { |
| grpc_error* error = GRPC_ERROR_NONE; |
| grpc_ares_hostbyname_request* hr = nullptr; |
| grpc_ares_request* r = nullptr; |
| ares_channel* channel = nullptr; |
| /* TODO(zyc): Enable tracing after #9603 is checked in */ |
| /* if (grpc_dns_trace) { |
| gpr_log(GPR_DEBUG, "resolve_address (blocking): name=%s, default_port=%s", |
| name, default_port); |
| } */ |
| |
| /* parse name, splitting it into host and port parts */ |
| char* host; |
| char* port; |
| gpr_split_host_port(name, &host, &port); |
| if (host == nullptr) { |
| error = grpc_error_set_str( |
| GRPC_ERROR_CREATE_FROM_STATIC_STRING("unparseable host:port"), |
| GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name)); |
| goto error_cleanup; |
| } else if (port == nullptr) { |
| if (default_port == nullptr) { |
| error = grpc_error_set_str( |
| GRPC_ERROR_CREATE_FROM_STATIC_STRING("no port in name"), |
| GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name)); |
| goto error_cleanup; |
| } |
| port = gpr_strdup(default_port); |
| } |
| |
| grpc_ares_ev_driver* ev_driver; |
| error = grpc_ares_ev_driver_create(&ev_driver, interested_parties); |
| if (error != GRPC_ERROR_NONE) goto error_cleanup; |
| |
| r = static_cast<grpc_ares_request*>(gpr_zalloc(sizeof(grpc_ares_request))); |
| gpr_mu_init(&r->mu); |
| r->ev_driver = ev_driver; |
| r->on_done = on_done; |
| r->lb_addrs_out = addrs; |
| r->service_config_json_out = service_config_json; |
| r->success = false; |
| r->error = GRPC_ERROR_NONE; |
| channel = grpc_ares_ev_driver_get_channel(r->ev_driver); |
| |
| // If dns_server is specified, use it. |
| if (dns_server != nullptr) { |
| gpr_log(GPR_INFO, "Using DNS server %s", dns_server); |
| grpc_resolved_address addr; |
| if (grpc_parse_ipv4_hostport(dns_server, &addr, false /* log_errors */)) { |
| r->dns_server_addr.family = AF_INET; |
| struct sockaddr_in* in = reinterpret_cast<struct sockaddr_in*>(addr.addr); |
| memcpy(&r->dns_server_addr.addr.addr4, &in->sin_addr, |
| sizeof(struct in_addr)); |
| r->dns_server_addr.tcp_port = grpc_sockaddr_get_port(&addr); |
| r->dns_server_addr.udp_port = grpc_sockaddr_get_port(&addr); |
| } else if (grpc_parse_ipv6_hostport(dns_server, &addr, |
| false /* log_errors */)) { |
| r->dns_server_addr.family = AF_INET6; |
| struct sockaddr_in6* in6 = reinterpret_cast<struct sockaddr_in6*>(addr.addr); |
| memcpy(&r->dns_server_addr.addr.addr6, &in6->sin6_addr, |
| sizeof(struct in6_addr)); |
| r->dns_server_addr.tcp_port = grpc_sockaddr_get_port(&addr); |
| r->dns_server_addr.udp_port = grpc_sockaddr_get_port(&addr); |
| } else { |
| error = grpc_error_set_str( |
| GRPC_ERROR_CREATE_FROM_STATIC_STRING("cannot parse authority"), |
| GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name)); |
| gpr_free(r); |
| goto error_cleanup; |
| } |
| int status = ares_set_servers_ports(*channel, &r->dns_server_addr); |
| if (status != ARES_SUCCESS) { |
| char* error_msg; |
| gpr_asprintf(&error_msg, "C-ares status is not ARES_SUCCESS: %s", |
| ares_strerror(status)); |
| error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_msg); |
| gpr_free(error_msg); |
| gpr_free(r); |
| goto error_cleanup; |
| } |
| } |
| gpr_ref_init(&r->pending_queries, 1); |
| if (grpc_ipv6_loopback_available()) { |
| hr = create_hostbyname_request(r, host, strhtons(port), |
| false /* is_balancer */); |
| ares_gethostbyname(*channel, hr->host, AF_INET6, on_hostbyname_done_cb, hr); |
| } |
| hr = create_hostbyname_request(r, host, strhtons(port), |
| false /* is_balancer */); |
| ares_gethostbyname(*channel, hr->host, AF_INET, on_hostbyname_done_cb, hr); |
| if (check_grpclb) { |
| /* Query the SRV record */ |
| grpc_ares_request_ref(r); |
| char* service_name; |
| gpr_asprintf(&service_name, "_grpclb._tcp.%s", host); |
| ares_query(*channel, service_name, ns_c_in, ns_t_srv, on_srv_query_done_cb, |
| r); |
| gpr_free(service_name); |
| } |
| if (service_config_json != nullptr) { |
| grpc_ares_request_ref(r); |
| char* config_name; |
| gpr_asprintf(&config_name, "_grpc_config.%s", host); |
| ares_search(*channel, config_name, ns_c_in, ns_t_txt, on_txt_done_cb, r); |
| gpr_free(config_name); |
| } |
| /* TODO(zyc): Handle CNAME records here. */ |
| grpc_ares_ev_driver_start(r->ev_driver); |
| grpc_ares_request_unref(r); |
| gpr_free(host); |
| gpr_free(port); |
| return r; |
| |
| error_cleanup: |
| GRPC_CLOSURE_SCHED(on_done, error); |
| gpr_free(host); |
| gpr_free(port); |
| return nullptr; |
| } |
| |
| grpc_ares_request* (*grpc_dns_lookup_ares)( |
| const char* dns_server, const char* name, const char* default_port, |
| grpc_pollset_set* interested_parties, grpc_closure* on_done, |
| grpc_lb_addresses** addrs, bool check_grpclb, |
| char** service_config_json) = grpc_dns_lookup_ares_impl; |
| |
| void grpc_cancel_ares_request(grpc_ares_request* r) { |
| if (grpc_dns_lookup_ares == grpc_dns_lookup_ares_impl) { |
| grpc_ares_ev_driver_shutdown(r->ev_driver); |
| } |
| } |
| |
| grpc_error* grpc_ares_init(void) { |
| gpr_once_init(&g_basic_init, do_basic_init); |
| gpr_mu_lock(&g_init_mu); |
| int status = ares_library_init(ARES_LIB_INIT_ALL); |
| gpr_mu_unlock(&g_init_mu); |
| |
| if (status != ARES_SUCCESS) { |
| char* error_msg; |
| gpr_asprintf(&error_msg, "ares_library_init failed: %s", |
| ares_strerror(status)); |
| grpc_error* error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_msg); |
| gpr_free(error_msg); |
| return error; |
| } |
| return GRPC_ERROR_NONE; |
| } |
| |
| void grpc_ares_cleanup(void) { |
| gpr_mu_lock(&g_init_mu); |
| ares_library_cleanup(); |
| gpr_mu_unlock(&g_init_mu); |
| } |
| |
| /* |
| * grpc_resolve_address_ares related structs and functions |
| */ |
| |
| typedef struct grpc_resolve_address_ares_request { |
| /** the pointer to receive the resolved addresses */ |
| grpc_resolved_addresses** addrs_out; |
| /** currently resolving lb addresses */ |
| grpc_lb_addresses* lb_addrs; |
| /** closure to call when the resolve_address_ares request completes */ |
| grpc_closure* on_resolve_address_done; |
| /** a closure wrapping on_dns_lookup_done_cb, which should be invoked when the |
| grpc_dns_lookup_ares operation is done. */ |
| grpc_closure on_dns_lookup_done; |
| } grpc_resolve_address_ares_request; |
| |
| static void on_dns_lookup_done_cb(void* arg, grpc_error* error) { |
| grpc_resolve_address_ares_request* r = |
| static_cast<grpc_resolve_address_ares_request*>(arg); |
| grpc_resolved_addresses** resolved_addresses = r->addrs_out; |
| if (r->lb_addrs == nullptr || r->lb_addrs->num_addresses == 0) { |
| *resolved_addresses = nullptr; |
| } else { |
| *resolved_addresses = |
| static_cast<grpc_resolved_addresses*>(gpr_zalloc(sizeof(grpc_resolved_addresses))); |
| (*resolved_addresses)->naddrs = r->lb_addrs->num_addresses; |
| (*resolved_addresses)->addrs = static_cast<grpc_resolved_address*>(gpr_zalloc( |
| sizeof(grpc_resolved_address) * (*resolved_addresses)->naddrs)); |
| for (size_t i = 0; i < (*resolved_addresses)->naddrs; i++) { |
| GPR_ASSERT(!r->lb_addrs->addresses[i].is_balancer); |
| memcpy(&(*resolved_addresses)->addrs[i], |
| &r->lb_addrs->addresses[i].address, sizeof(grpc_resolved_address)); |
| } |
| } |
| GRPC_CLOSURE_SCHED(r->on_resolve_address_done, GRPC_ERROR_REF(error)); |
| if (r->lb_addrs != nullptr) grpc_lb_addresses_destroy(r->lb_addrs); |
| gpr_free(r); |
| } |
| |
| static void grpc_resolve_address_ares_impl(const char* name, |
| const char* default_port, |
| grpc_pollset_set* interested_parties, |
| grpc_closure* on_done, |
| grpc_resolved_addresses** addrs) { |
| grpc_resolve_address_ares_request* r = |
| static_cast<grpc_resolve_address_ares_request*>(gpr_zalloc( |
| sizeof(grpc_resolve_address_ares_request))); |
| r->addrs_out = addrs; |
| r->on_resolve_address_done = on_done; |
| GRPC_CLOSURE_INIT(&r->on_dns_lookup_done, on_dns_lookup_done_cb, r, |
| grpc_schedule_on_exec_ctx); |
| grpc_dns_lookup_ares(nullptr /* dns_server */, name, default_port, |
| interested_parties, &r->on_dns_lookup_done, &r->lb_addrs, |
| false /* check_grpclb */, |
| nullptr /* service_config_json */); |
| } |
| |
| void (*grpc_resolve_address_ares)( |
| const char* name, const char* default_port, |
| grpc_pollset_set* interested_parties, grpc_closure* on_done, |
| grpc_resolved_addresses** addrs) = grpc_resolve_address_ares_impl; |
| |
| #endif /* GRPC_ARES == 1 && !defined(GRPC_UV) */ |