Merge github.com:grpc/grpc into thread_pool

3 files changed, 76 insertions, 21 deletions

diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c
index 656c3a5860..861b809b19 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c
@@ -61,6 +61,8 @@
 typedef struct {
   /** base class: must be first */
   grpc_resolver base;
+  /** DNS server to use (if not system default) */
+  char *dns_server;
   /** name to resolve (usually the same as target_name) */
   char *name_to_resolve;
   /** default port to use */
@@ -172,6 +174,8 @@ static void dns_ares_on_resolved_locked(grpc_exec_ctx *exec_ctx, void *arg,
     grpc_resolved_addresses_destroy(r->addresses);
     grpc_lb_addresses_destroy(exec_ctx, addresses);
   } else {
+    const char *msg = grpc_error_string(error);
+    gpr_log(GPR_DEBUG, "dns resolution failed: %s", msg);
     gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
     gpr_timespec next_try = gpr_backoff_step(&r->backoff_state, now);
     gpr_timespec timeout = gpr_time_sub(next_try, now);
@@ -221,9 +225,9 @@ static void dns_ares_start_resolving_locked(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(!r->resolving);
   r->resolving = true;
   r->addresses = NULL;
-  grpc_resolve_address(exec_ctx, r->name_to_resolve, r->default_port,
-                       r->interested_parties, &r->dns_ares_on_resolved_locked,
-                       &r->addresses);
+  grpc_dns_lookup_ares(exec_ctx, r->dns_server, r->name_to_resolve,
+                       r->default_port, r->interested_parties,
+                       &r->dns_ares_on_resolved_locked, &r->addresses);
 }
 
 static void dns_ares_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
@@ -246,6 +250,7 @@ static void dns_ares_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *gr) {
     grpc_channel_args_destroy(exec_ctx, r->resolved_result);
   }
   grpc_pollset_set_destroy(exec_ctx, r->interested_parties);
+  gpr_free(r->dns_server);
   gpr_free(r->name_to_resolve);
   gpr_free(r->default_port);
   grpc_channel_args_destroy(exec_ctx, r->channel_args);
@@ -257,14 +262,13 @@ static grpc_resolver *dns_ares_create(grpc_exec_ctx *exec_ctx,
                                       const char *default_port) {
   // Get name from args.
   const char *path = args->uri->path;
-  if (0 != strcmp(args->uri->authority, "")) {
-    gpr_log(GPR_ERROR, "authority based dns uri's not supported");
-    return NULL;
-  }
   if (path[0] == '/') ++path;
   // Create resolver.
   ares_dns_resolver *r = gpr_zalloc(sizeof(ares_dns_resolver));
   grpc_resolver_init(&r->base, &dns_ares_resolver_vtable, args->combiner);
+  if (0 != strcmp(args->uri->authority, "")) {
+    r->dns_server = gpr_strdup(args->uri->authority);
+  }
   r->name_to_resolve = gpr_strdup(path);
   r->default_port = gpr_strdup(default_port);
   r->channel_args = grpc_channel_args_copy(args->args);
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 09c46a66e0..e0cfd8b629 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
@@ -48,7 +48,10 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/time.h>
 #include <grpc/support/useful.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/sockaddr_utils.h"
@@ -58,6 +61,8 @@ static gpr_once g_basic_init = GPR_ONCE_INIT;
 static gpr_mu g_init_mu;
 
 typedef 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 */
   /** host to resolve, parsed from the name to resolve */
   char *host;
@@ -192,11 +197,12 @@ static void on_done_cb(void *arg, int status, int timeouts,
   grpc_ares_request_unref(NULL, r);
 }
 
-void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx, const char *name,
-                                    const char *default_port,
-                                    grpc_pollset_set *interested_parties,
-                                    grpc_closure *on_done,
-                                    grpc_resolved_addresses **addrs) {
+void 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_resolved_addresses **addrs) {
+  grpc_error *error = GRPC_ERROR_NONE;
   /* 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",
@@ -208,28 +214,23 @@ void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx, const char *name,
   char *port;
   gpr_split_host_port(name, &host, &port);
   if (host == NULL) {
-    grpc_error *err = grpc_error_set_str(
+    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));
-    grpc_closure_sched(exec_ctx, on_done, err);
     goto error_cleanup;
   } else if (port == NULL) {
     if (default_port == NULL) {
-      grpc_error *err = grpc_error_set_str(
+      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));
-      grpc_closure_sched(exec_ctx, on_done, err);
       goto error_cleanup;
     }
     port = gpr_strdup(default_port);
   }
 
   grpc_ares_ev_driver *ev_driver;
-  grpc_error *err = grpc_ares_ev_driver_create(&ev_driver, interested_parties);
-  if (err != GRPC_ERROR_NONE) {
-    GRPC_LOG_IF_ERROR("grpc_ares_ev_driver_create() failed", err);
-    goto error_cleanup;
-  }
+  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));
   gpr_mu_init(&r->mu);
@@ -242,6 +243,40 @@ void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx, const char *name,
   r->success = false;
   r->error = GRPC_ERROR_NONE;
   ares_channel *channel = grpc_ares_ev_driver_get_channel(r->ev_driver);
+
+  // If dns_server is specified, use it.
+  if (dns_server != NULL) {
+    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;
+      memcpy(&r->dns_server_addr.addr.addr4, addr.addr, addr.len);
+      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);
+      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));
+      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);
+      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, 2);
   if (grpc_ipv6_loopback_available()) {
     gpr_ref(&r->pending_queries);
@@ -254,10 +289,20 @@ void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx, const char *name,
   return;
 
 error_cleanup:
+  grpc_closure_sched(exec_ctx, on_done, error);
   gpr_free(host);
   gpr_free(port);
 }
 
+void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx, const char *name,
+                                    const char *default_port,
+                                    grpc_pollset_set *interested_parties,
+                                    grpc_closure *on_done,
+                                    grpc_resolved_addresses **addrs) {
+  grpc_dns_lookup_ares(exec_ctx, NULL /* dns_server */, name, default_port,
+                       interested_parties, on_done, addrs);
+}
+
 void (*grpc_resolve_address_ares)(
     grpc_exec_ctx *exec_ctx, const char *name, const char *default_port,
     grpc_pollset_set *interested_parties, grpc_closure *on_done,
diff --git 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
index 3dd40ea268..84fd7fcbd6 100644
--- 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
@@ -51,6 +51,12 @@ extern void (*grpc_resolve_address_ares)(grpc_exec_ctx *exec_ctx,
                                          grpc_closure *on_done,
                                          grpc_resolved_addresses **addresses);
 
+void grpc_dns_lookup_ares(grpc_exec_ctx *exec_ctx, const char *dns_server,
+                          const char *addr, const char *default_port,
+                          grpc_pollset_set *interested_parties,
+                          grpc_closure *on_done,
+                          grpc_resolved_addresses **addresses);
+
 /* Initialize gRPC ares wrapper. Must be called at least once before
    grpc_resolve_address_ares(). */
 grpc_error *grpc_ares_init(void);