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 #include <grpc/support/port_platform.h>
19
20 #include "src/core/lib/iomgr/port.h"
21 #if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER)
22
23 #include <ares.h>
24 #include <string.h>
25 #include <sys/ioctl.h>
26
27 #include "absl/strings/str_cat.h"
28
29 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h"
30
31 #include <grpc/support/alloc.h>
32 #include <grpc/support/log.h>
33 #include <grpc/support/string_util.h>
34 #include <grpc/support/time.h>
35 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
36 #include "src/core/lib/gpr/string.h"
37 #include "src/core/lib/iomgr/ev_posix.h"
38 #include "src/core/lib/iomgr/iomgr_internal.h"
39 #include "src/core/lib/iomgr/sockaddr_utils.h"
40
41 namespace grpc_core {
42
43 class GrpcPolledFdPosix : public GrpcPolledFd {
44 public:
GrpcPolledFdPosix(ares_socket_t as,grpc_pollset_set * driver_pollset_set)45 GrpcPolledFdPosix(ares_socket_t as, grpc_pollset_set* driver_pollset_set)
46 : name_(absl::StrCat("c-ares fd: ", static_cast<int>(as))), as_(as) {
47 fd_ = grpc_fd_create(static_cast<int>(as), name_.c_str(), false);
48 driver_pollset_set_ = driver_pollset_set;
49 grpc_pollset_set_add_fd(driver_pollset_set_, fd_);
50 }
51
~GrpcPolledFdPosix()52 ~GrpcPolledFdPosix() override {
53 grpc_pollset_set_del_fd(driver_pollset_set_, fd_);
54 /* c-ares library will close the fd inside grpc_fd. This fd may be picked up
55 immediately by another thread, and should not be closed by the following
56 grpc_fd_orphan. */
57 int dummy_release_fd;
58 grpc_fd_orphan(fd_, nullptr, &dummy_release_fd, "c-ares query finished");
59 }
60
RegisterForOnReadableLocked(grpc_closure * read_closure)61 void RegisterForOnReadableLocked(grpc_closure* read_closure) override {
62 grpc_fd_notify_on_read(fd_, read_closure);
63 }
64
RegisterForOnWriteableLocked(grpc_closure * write_closure)65 void RegisterForOnWriteableLocked(grpc_closure* write_closure) override {
66 grpc_fd_notify_on_write(fd_, write_closure);
67 }
68
IsFdStillReadableLocked()69 bool IsFdStillReadableLocked() override {
70 size_t bytes_available = 0;
71 return ioctl(grpc_fd_wrapped_fd(fd_), FIONREAD, &bytes_available) == 0 &&
72 bytes_available > 0;
73 }
74
ShutdownLocked(grpc_error * error)75 void ShutdownLocked(grpc_error* error) override {
76 grpc_fd_shutdown(fd_, error);
77 }
78
GetWrappedAresSocketLocked()79 ares_socket_t GetWrappedAresSocketLocked() override { return as_; }
80
GetName()81 const char* GetName() override { return name_.c_str(); }
82
83 private:
84 std::string name_;
85 ares_socket_t as_;
86 grpc_fd* fd_;
87 grpc_pollset_set* driver_pollset_set_;
88 };
89
90 class GrpcPolledFdFactoryPosix : public GrpcPolledFdFactory {
91 public:
NewGrpcPolledFdLocked(ares_socket_t as,grpc_pollset_set * driver_pollset_set,std::shared_ptr<WorkSerializer>)92 GrpcPolledFd* NewGrpcPolledFdLocked(
93 ares_socket_t as, grpc_pollset_set* driver_pollset_set,
94 std::shared_ptr<WorkSerializer> /*work_serializer*/) override {
95 return new GrpcPolledFdPosix(as, driver_pollset_set);
96 }
97
ConfigureAresChannelLocked(ares_channel)98 void ConfigureAresChannelLocked(ares_channel /*channel*/) override {}
99 };
100
NewGrpcPolledFdFactory(std::shared_ptr<WorkSerializer> work_serializer)101 std::unique_ptr<GrpcPolledFdFactory> NewGrpcPolledFdFactory(
102 std::shared_ptr<WorkSerializer> work_serializer) {
103 (void)work_serializer;
104 return absl::make_unique<GrpcPolledFdFactoryPosix>();
105 }
106
107 } // namespace grpc_core
108
109 #endif /* GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER) */
110