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 120000
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, ...) \
37 if (GRPC_TRACE_FLAG_ENABLED(grpc_trace_cares_resolver)) { \
38 gpr_log(GPR_DEBUG, "(c-ares resolver) " format, __VA_ARGS__); \
42 typedef struct grpc_ares_request grpc_ares_request;
44 /* Asynchronously resolve \a name. Use \a default_port if a port isn't
45 designated in \a name, otherwise use the port in \a name. grpc_ares_init()
46 must be called at least once before this function. \a on_done may be
47 called directly in this function without being scheduled with \a exec_ctx,
48 so it must not try to acquire locks that are being held by the caller. */
49 extern void (*grpc_resolve_address_ares)(const char* name,
50 const char* default_port,
51 grpc_pollset_set* interested_parties,
52 grpc_closure* on_done,
53 grpc_resolved_addresses** addresses);
55 /* Asynchronously resolve \a name. It will try to resolve grpclb SRV records in
56 addition to the normal address records. For normal address records, it uses
57 \a default_port if a port isn't designated in \a name, otherwise it uses the
58 port in \a name. grpc_ares_init() must be called at least once before this
59 function. \a on_done may be called directly in this function without being
60 scheduled with \a exec_ctx, so it must not try to acquire locks that are
61 being held by the caller. The returned grpc_ares_request object is owned
62 by the caller and it is safe to free after on_done is called back. */
63 extern grpc_ares_request* (*grpc_dns_lookup_ares_locked)(
64 const char* dns_server, const char* name, const char* default_port,
65 grpc_pollset_set* interested_parties, grpc_closure* on_done,
66 grpc_core::UniquePtr<grpc_core::ServerAddressList>* addresses,
67 bool check_grpclb, char** service_config_json, int query_timeout_ms,
68 grpc_combiner* combiner);
70 /* Cancel the pending grpc_ares_request \a request */
71 extern void (*grpc_cancel_ares_request_locked)(grpc_ares_request* request);
73 /* Initialize gRPC ares wrapper. Must be called at least once before
74 grpc_resolve_address_ares(). */
75 grpc_error* grpc_ares_init(void);
77 /* Uninitialized gRPC ares wrapper. If there was more than one previous call to
78 grpc_ares_init(), this function uninitializes the gRPC ares wrapper only if
79 it has been called the same number of times as grpc_ares_init(). */
80 void grpc_ares_cleanup(void);
82 /** Schedules the desired callback for request completion
83 * and destroys the grpc_ares_request */
84 void grpc_ares_complete_request_locked(grpc_ares_request* request);
86 /* Indicates whether or not AAAA queries should be attempted. */
87 /* E.g., return false if ipv6 is known to not be available. */
88 bool grpc_ares_query_ipv6();
90 /* Sorts destinations in lb_addrs according to RFC 6724. */
91 void grpc_cares_wrapper_address_sorting_sort(
92 grpc_core::ServerAddressList* addresses);
94 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_WRAPPER_H \