diff options
Diffstat (limited to 'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c')
| -rw-r--r-- | src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c | 88 |
1 files changed, 78 insertions, 10 deletions
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c index 9065e33613..e65723a63b 100644 --- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c +++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c @@ -33,13 +33,13 @@ #include <grpc/support/string_util.h> #include <grpc/support/time.h> #include <grpc/support/useful.h> -#include <nameser.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/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" #include "src/core/lib/support/string.h" @@ -54,6 +54,8 @@ struct grpc_ares_request { 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 */ @@ -266,10 +268,68 @@ static void on_srv_query_done_cb(void *arg, int status, int timeouts, grpc_exec_ctx_finish(&exec_ctx); } +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 = (grpc_ares_request *)arg; + gpr_mu_lock(&r->mu); + if (status != ARES_SUCCESS) goto fail; + struct ares_txt_ext *reply = NULL; + status = ares_parse_txt_reply_ext(buf, len, &reply); + if (status != ARES_SUCCESS) goto fail; + // Find service config in TXT record. + const size_t prefix_len = sizeof(g_service_config_attribute_prefix) - 1; + struct ares_txt_ext *result; + for (result = reply; result != NULL; 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 != NULL) { + size_t service_config_len = result->length - prefix_len; + *r->service_config_json_out = gpr_malloc(service_config_len + 1); + memcpy(*r->service_config_json_out, result->txt + prefix_len, + service_config_len); + for (result = result->next; result != NULL && !result->record_start; + result = result->next) { + *r->service_config_json_out = 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)); + 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); + } +done: + gpr_mu_unlock(&r->mu); + grpc_ares_request_unref(NULL, r); +} + static grpc_ares_request *grpc_dns_lookup_ares_impl( grpc_exec_ctx *exec_ctx, 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) { + grpc_closure *on_done, grpc_lb_addresses **addrs, bool check_grpclb, + char **service_config_json) { grpc_error *error = GRPC_ERROR_NONE; /* TODO(zyc): Enable tracing after #9603 is checked in */ /* if (grpc_dns_trace) { @@ -300,11 +360,12 @@ static grpc_ares_request *grpc_dns_lookup_ares_impl( error = grpc_ares_ev_driver_create(&ev_driver, interested_parties); if (error != GRPC_ERROR_NONE) goto error_cleanup; - grpc_ares_request *r = gpr_malloc(sizeof(grpc_ares_request)); + grpc_ares_request *r = 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; ares_channel *channel = grpc_ares_ev_driver_get_channel(r->ev_driver); @@ -315,13 +376,17 @@ static grpc_ares_request *grpc_dns_lookup_ares_impl( grpc_resolved_address addr; if (grpc_parse_ipv4_hostport(dns_server, &addr, false /* log_errors */)) { r->dns_server_addr.family = AF_INET; - memcpy(&r->dns_server_addr.addr.addr4, addr.addr, addr.len); + struct sockaddr_in *in = (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; - memcpy(&r->dns_server_addr.addr.addr6, addr.addr, addr.len); + struct sockaddr_in6 *in6 = (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 { @@ -342,8 +407,6 @@ static grpc_ares_request *grpc_dns_lookup_ares_impl( goto error_cleanup; } } - // An extra reference is put here to avoid destroying the request in - // on_done_cb before calling grpc_ares_ev_driver_start. gpr_ref_init(&r->pending_queries, 1); if (grpc_ipv6_loopback_available()) { grpc_ares_hostbyname_request *hr = create_hostbyname_request( @@ -362,6 +425,10 @@ static grpc_ares_request *grpc_dns_lookup_ares_impl( r); gpr_free(service_name); } + if (service_config_json != NULL) { + grpc_ares_request_ref(r); + ares_search(*channel, hr->host, ns_c_in, ns_t_txt, on_txt_done_cb, r); + } /* TODO(zyc): Handle CNAME records here. */ grpc_ares_ev_driver_start(exec_ctx, r->ev_driver); grpc_ares_request_unref(exec_ctx, r); @@ -379,8 +446,8 @@ error_cleanup: grpc_ares_request *(*grpc_dns_lookup_ares)( grpc_exec_ctx *exec_ctx, 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) = grpc_dns_lookup_ares_impl; + 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_exec_ctx *exec_ctx, grpc_ares_request *r) { if (grpc_dns_lookup_ares == grpc_dns_lookup_ares_impl) { @@ -465,7 +532,8 @@ static void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx, grpc_schedule_on_exec_ctx); grpc_dns_lookup_ares(exec_ctx, NULL /* dns_server */, name, default_port, interested_parties, &r->on_dns_lookup_done, &r->lb_addrs, - false /* check_grpclb */); + false /* check_grpclb */, + NULL /* service_config_json */); } void (*grpc_resolve_address_ares)( |