Allow specifying DNS server to query for c-ares via URI authority.
diff --git a/src/core/ext/filters/client_channel/parse_address.c b/src/core/ext/filters/client_channel/parse_address.c
index edc6ce6..18381ee 100644
--- a/src/core/ext/filters/client_channel/parse_address.c
+++ b/src/core/ext/filters/client_channel/parse_address.c
@@ -57,11 +57,11 @@
struct sockaddr_un *un = (struct sockaddr_un *)resolved_addr->addr;
const size_t maxlen = sizeof(un->sun_path);
const size_t path_len = strnlen(uri->path, maxlen);
- if (path_len == maxlen) return 0;
+ if (path_len == maxlen) return false;
un->sun_family = AF_UNIX;
strcpy(un->sun_path, uri->path);
resolved_addr->len = sizeof(*un);
- return 1;
+ return true;
}
#else /* GRPC_HAVE_UNIX_SOCKET */
@@ -73,6 +73,40 @@
#endif /* GRPC_HAVE_UNIX_SOCKET */
+bool grpc_parse_ipv4_hostport(const char *hostport, grpc_resolved_address *addr,
+ bool log_errors) {
+ bool success = false;
+ // Split host and port.
+ char *host;
+ char *port;
+ if (!gpr_split_host_port(hostport, &host, &port)) return false;
+ // Parse IP address.
+ memset(addr, 0, sizeof(*addr));
+ addr->len = sizeof(struct sockaddr_in);
+ struct sockaddr_in *in = (struct sockaddr_in *)addr->addr;
+ in->sin_family = AF_INET;
+ if (inet_pton(AF_INET, host, &in->sin_addr) == 0) {
+ if (log_errors) gpr_log(GPR_ERROR, "invalid ipv4 address: '%s'", host);
+ goto done;
+ }
+ // Parse port.
+ if (port == NULL) {
+ if (log_errors) gpr_log(GPR_ERROR, "no port given for ipv4 scheme");
+ goto done;
+ }
+ int port_num;
+ if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 || port_num > 65535) {
+ if (log_errors) gpr_log(GPR_ERROR, "invalid ipv4 port: '%s'", port);
+ goto done;
+ }
+ in->sin_port = htons((uint16_t)port_num);
+ success = true;
+done:
+ gpr_free(host);
+ gpr_free(port);
+ return success;
+}
+
bool grpc_parse_ipv4(const grpc_uri *uri,
grpc_resolved_address *resolved_addr) {
if (strcmp("ipv4", uri->scheme) != 0) {
@@ -80,67 +114,24 @@
return false;
}
const char *host_port = uri->path;
- char *host;
- char *port;
- int port_num;
- bool result = false;
- struct sockaddr_in *in = (struct sockaddr_in *)resolved_addr->addr;
-
if (*host_port == '/') ++host_port;
- if (!gpr_split_host_port(host_port, &host, &port)) {
- return false;
- }
-
- memset(resolved_addr, 0, sizeof(grpc_resolved_address));
- resolved_addr->len = sizeof(struct sockaddr_in);
- in->sin_family = AF_INET;
- if (inet_pton(AF_INET, host, &in->sin_addr) == 0) {
- gpr_log(GPR_ERROR, "invalid ipv4 address: '%s'", host);
- goto done;
- }
-
- if (port != NULL) {
- if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 ||
- port_num > 65535) {
- gpr_log(GPR_ERROR, "invalid ipv4 port: '%s'", port);
- goto done;
- }
- in->sin_port = htons((uint16_t)port_num);
- } else {
- gpr_log(GPR_ERROR, "no port given for ipv4 scheme");
- goto done;
- }
-
- result = true;
-done:
- gpr_free(host);
- gpr_free(port);
- return result;
+ return grpc_parse_ipv4_hostport(host_port, resolved_addr,
+ true /* log_errors */);
}
-bool grpc_parse_ipv6(const grpc_uri *uri,
- grpc_resolved_address *resolved_addr) {
- if (strcmp("ipv6", uri->scheme) != 0) {
- gpr_log(GPR_ERROR, "Expected 'ipv6' scheme, got '%s'", uri->scheme);
- return false;
- }
- const char *host_port = uri->path;
+bool grpc_parse_ipv6_hostport(const char *hostport, grpc_resolved_address *addr,
+ bool log_errors) {
+ bool success = false;
+ // Split host and port.
char *host;
char *port;
- int port_num;
- int result = 0;
- struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)resolved_addr->addr;
-
- if (*host_port == '/') ++host_port;
- if (!gpr_split_host_port(host_port, &host, &port)) {
- return 0;
- }
-
- memset(in6, 0, sizeof(*in6));
- resolved_addr->len = sizeof(*in6);
+ if (!gpr_split_host_port(hostport, &host, &port)) return false;
+ // Parse IP address.
+ memset(addr, 0, sizeof(*addr));
+ addr->len = sizeof(struct sockaddr_in6);
+ struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)addr->addr;
in6->sin6_family = AF_INET6;
-
- /* Handle the RFC6874 syntax for IPv6 zone identifiers. */
+ // Handle the RFC6874 syntax for IPv6 zone identifiers.
char *host_end = (char *)gpr_memrchr(host, '%', strlen(host));
if (host_end != NULL) {
GPR_ASSERT(host_end >= host);
@@ -159,7 +150,7 @@
gpr_log(GPR_ERROR, "invalid ipv6 scope id: '%s'", host_end + 1);
goto done;
}
- // Handle "sin6_scope_id" being type "u_long". See grpc issue ##10027.
+ // Handle "sin6_scope_id" being type "u_long". See grpc issue #10027.
in6->sin6_scope_id = sin6_scope_id;
} else {
if (inet_pton(AF_INET6, host, &in6->sin6_addr) == 0) {
@@ -167,24 +158,34 @@
goto done;
}
}
-
- if (port != NULL) {
- if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 ||
- port_num > 65535) {
- gpr_log(GPR_ERROR, "invalid ipv6 port: '%s'", port);
- goto done;
- }
- in6->sin6_port = htons((uint16_t)port_num);
- } else {
- gpr_log(GPR_ERROR, "no port given for ipv6 scheme");
+ // Parse port.
+ if (port == NULL) {
+ if (log_errors) gpr_log(GPR_ERROR, "no port given for ipv6 scheme");
goto done;
}
-
- result = 1;
+ int port_num;
+ if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 || port_num > 65535) {
+ if (log_errors) gpr_log(GPR_ERROR, "invalid ipv6 port: '%s'", port);
+ goto done;
+ }
+ in6->sin6_port = htons((uint16_t)port_num);
+ success = true;
done:
gpr_free(host);
gpr_free(port);
- return result;
+ return success;
+}
+
+bool grpc_parse_ipv6(const grpc_uri *uri,
+ grpc_resolved_address *resolved_addr) {
+ if (strcmp("ipv6", uri->scheme) != 0) {
+ gpr_log(GPR_ERROR, "Expected 'ipv6' scheme, got '%s'", uri->scheme);
+ return false;
+ }
+ const char *host_port = uri->path;
+ if (*host_port == '/') ++host_port;
+ return grpc_parse_ipv6_hostport(host_port, resolved_addr,
+ true /* log_errors */);
}
bool grpc_parse_uri(const grpc_uri *uri, grpc_resolved_address *resolved_addr) {
diff --git a/src/core/ext/filters/client_channel/parse_address.h b/src/core/ext/filters/client_channel/parse_address.h
index fa7ea33..1a203a3 100644
--- a/src/core/ext/filters/client_channel/parse_address.h
+++ b/src/core/ext/filters/client_channel/parse_address.h
@@ -54,4 +54,10 @@
/** Populate \a resolved_addr from \a uri. Returns true upon success. */
bool grpc_parse_uri(const grpc_uri *uri, grpc_resolved_address *resolved_addr);
+/** Parse bare IPv4 or IPv6 "IP:port" strings. */
+bool grpc_parse_ipv4_hostport(const char *hostport, grpc_resolved_address *addr,
+ bool log_errors);
+bool grpc_parse_ipv6_hostport(const char *hostport, grpc_resolved_address *addr,
+ bool log_errors);
+
#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_PARSE_ADDRESS_H */
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 ffaeeed..578e8d6 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 @@
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 @@
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 @@
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 @@
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 09c46a6..e0cfd8b 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_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 @@
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 @@
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 @@
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 @@
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 3dd40ea..84fd7fc 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 @@
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);