3 * Copyright 2016 gRPC authors.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
19 #ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_WRAPPER_H
20 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_WRAPPER_H
22 #include <grpc/support/port_platform.h>
24 #include "src/core/ext/filters/client_channel/server_address.h"
25 #include "src/core/lib/iomgr/iomgr.h"
26 #include "src/core/lib/iomgr/polling_entity.h"
27 #include "src/core/lib/iomgr/resolve_address.h"
29 #define GRPC_DNS_ARES_DEFAULT_QUERY_TIMEOUT_MS 10000
31 extern grpc_core::TraceFlag grpc_trace_cares_address_sorting;
33 extern grpc_core::TraceFlag grpc_trace_cares_resolver;
35 #define GRPC_CARES_TRACE_LOG(format, ...) \
36 if (grpc_trace_cares_resolver.enabled()) { \
37 gpr_log(GPR_DEBUG, "(c-ares resolver) " format, __VA_ARGS__); \
40 typedef struct grpc_ares_request grpc_ares_request;
42 /* Asynchronously resolve \a name. Use \a default_port if a port isn't
43 designated in \a name, otherwise use the port in \a name. grpc_ares_init()
44 must be called at least once before this function. \a on_done may be
45 called directly in this function without being scheduled with \a exec_ctx,
46 so it must not try to acquire locks that are being held by the caller. */
47 extern void (*grpc_resolve_address_ares)(const char* name,
48 const char* default_port,
49 grpc_pollset_set* interested_parties,
50 grpc_closure* on_done,
51 grpc_resolved_addresses** addresses);
53 /* Asynchronously resolve \a name. It will try to resolve grpclb SRV records in
54 addition to the normal address records. For normal address records, it uses
55 \a default_port if a port isn't designated in \a name, otherwise it uses the
56 port in \a name. grpc_ares_init() must be called at least once before this
57 function. \a on_done may be called directly in this function without being
58 scheduled with \a exec_ctx, so it must not try to acquire locks that are
59 being held by the caller. The returned grpc_ares_request object is owned
60 by the caller and it is safe to free after on_done is called back. */
61 extern grpc_ares_request* (*grpc_dns_lookup_ares_locked)(
62 const char* dns_server, const char* name, const char* default_port,
63 grpc_pollset_set* interested_parties, grpc_closure* on_done,
64 grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses,
65 bool check_grpclb, char** service_config_json, int query_timeout_ms,
66 grpc_combiner* combiner);
68 /* Cancel the pending grpc_ares_request \a request */
69 extern void (*grpc_cancel_ares_request_locked)(grpc_ares_request* request);
71 /* Initialize gRPC ares wrapper. Must be called at least once before
72 grpc_resolve_address_ares(). */
73 grpc_error* grpc_ares_init(void);
75 /* Uninitialized gRPC ares wrapper. If there was more than one previous call to
76 grpc_ares_init(), this function uninitializes the gRPC ares wrapper only if
77 it has been called the same number of times as grpc_ares_init(). */
78 void grpc_ares_cleanup(void);
80 /** Schedules the desired callback for request completion
81 * and destroys the grpc_ares_request */
82 void grpc_ares_complete_request_locked(grpc_ares_request* request);
84 /* Indicates whether or not AAAA queries should be attempted. */
85 /* E.g., return false if ipv6 is known to not be available. */
86 bool grpc_ares_query_ipv6();
88 /* Maybe (depending on the current platform) checks if "name" matches
89 * "localhost" and if so fills in addrs with the correct sockaddr structures.
90 * Returns a bool indicating whether or not such an action was performed.
91 * See https://github.com/grpc/grpc/issues/15158. */
92 bool grpc_ares_maybe_resolve_localhost_manually_locked(
93 const char* name, const char* default_port,
94 grpc_core::UniquePtr<grpc_core::ServerAddressList>* addrs);
96 /* Sorts destinations in lb_addrs according to RFC 6724. */
97 void grpc_cares_wrapper_address_sorting_sort(
98 grpc_core::ServerAddressList* addresses);
100 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_WRAPPER_H \