1 /* 2 * 3 * Copyright 2016 gRPC authors. 4 * 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 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 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. 16 * 17 */ 18 19 #ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H 20 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H 21 22 #include <grpc/support/port_platform.h> 23 24 #include <ares.h> 25 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h" 26 #include "src/core/lib/gprpp/abstract.h" 27 #include "src/core/lib/iomgr/pollset_set.h" 28 29 typedef struct grpc_ares_ev_driver grpc_ares_ev_driver; 30 31 /* Start \a ev_driver. It will keep working until all IO on its ares_channel is 32 done, or grpc_ares_ev_driver_destroy() is called. It may notify the callbacks 33 bound to its ares_channel when necessary. */ 34 void grpc_ares_ev_driver_start_locked(grpc_ares_ev_driver* ev_driver); 35 36 /* Returns the ares_channel owned by \a ev_driver. To bind a c-ares query to 37 \a ev_driver, use the ares_channel owned by \a ev_driver as the arg of the 38 query. */ 39 ares_channel* grpc_ares_ev_driver_get_channel_locked( 40 grpc_ares_ev_driver* ev_driver); 41 42 /* Creates a new grpc_ares_ev_driver. Returns GRPC_ERROR_NONE if \a ev_driver is 43 created successfully. */ 44 grpc_error* grpc_ares_ev_driver_create_locked(grpc_ares_ev_driver** ev_driver, 45 grpc_pollset_set* pollset_set, 46 grpc_combiner* combiner, 47 grpc_ares_request* request); 48 49 /* Called back when all DNS lookups have completed. */ 50 void grpc_ares_ev_driver_on_queries_complete_locked( 51 grpc_ares_ev_driver* ev_driver); 52 53 /* Shutdown all the grpc_fds used by \a ev_driver */ 54 void grpc_ares_ev_driver_shutdown_locked(grpc_ares_ev_driver* ev_driver); 55 56 namespace grpc_core { 57 58 /* A wrapped fd that integrates with the grpc iomgr of the current platform. 59 * A GrpcPolledFd knows how to create grpc platform-specific iomgr endpoints 60 * from "ares_socket_t" sockets, and then sign up for readability/writeability 61 * with that poller, and do shutdown and destruction. */ 62 class GrpcPolledFd { 63 public: 64 virtual ~GrpcPolledFd() {} 65 /* Called when c-ares library is interested and there's no pending callback */ 66 virtual void RegisterForOnReadableLocked(grpc_closure* read_closure) 67 GRPC_ABSTRACT; 68 /* Called when c-ares library is interested and there's no pending callback */ 69 virtual void RegisterForOnWriteableLocked(grpc_closure* write_closure) 70 GRPC_ABSTRACT; 71 /* Indicates if there is data left even after just being read from */ 72 virtual bool IsFdStillReadableLocked() GRPC_ABSTRACT; 73 /* Called once and only once. Must cause cancellation of any pending 74 * read/write callbacks. */ 75 virtual void ShutdownLocked(grpc_error* error) GRPC_ABSTRACT; 76 /* Get the underlying ares_socket_t that this was created from */ 77 virtual ares_socket_t GetWrappedAresSocketLocked() GRPC_ABSTRACT; 78 /* A unique name, for logging */ 79 virtual const char* GetName() GRPC_ABSTRACT; 80 81 GRPC_ABSTRACT_BASE_CLASS 82 }; 83 84 /* A GrpcPolledFdFactory is 1-to-1 with and owned by the 85 * ares event driver. It knows how to create GrpcPolledFd's 86 * for the current platform, and the ares driver uses it for all of 87 * its fd's. */ 88 class GrpcPolledFdFactory { 89 public: 90 virtual ~GrpcPolledFdFactory() {} 91 /* Creates a new wrapped fd for the current platform */ 92 virtual GrpcPolledFd* NewGrpcPolledFdLocked( 93 ares_socket_t as, grpc_pollset_set* driver_pollset_set, 94 grpc_combiner* combiner) GRPC_ABSTRACT; 95 /* Optionally configures the ares channel after creation */ 96 virtual void ConfigureAresChannelLocked(ares_channel channel) GRPC_ABSTRACT; 97 98 GRPC_ABSTRACT_BASE_CLASS 99 }; 100 101 UniquePtr<GrpcPolledFdFactory> NewGrpcPolledFdFactory(grpc_combiner* combiner); 102 103 } // namespace grpc_core 104 105 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H \ 106 */ 107
