1 //
2 //
3 // Copyright 2015 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 #include <grpc/support/port_platform.h>
20
21 #include "src/core/lib/iomgr/port.h"
22 #ifdef GRPC_POSIX_SOCKET_RESOLVE_ADDRESS
23
24 #include <grpc/support/alloc.h>
25 #include <grpc/support/string_util.h>
26 #include <grpc/support/time.h>
27 #include <string.h>
28 #include <sys/types.h>
29
30 #include "src/core/lib/event_engine/default_event_engine.h"
31 #include "src/core/lib/iomgr/block_annotate.h"
32 #include "src/core/lib/iomgr/exec_ctx.h"
33 #include "src/core/lib/iomgr/executor.h"
34 #include "src/core/lib/iomgr/iomgr_internal.h"
35 #include "src/core/lib/iomgr/resolve_address.h"
36 #include "src/core/lib/iomgr/resolve_address_posix.h"
37 #include "src/core/lib/iomgr/sockaddr.h"
38 #include "src/core/lib/iomgr/unix_sockets_posix.h"
39 #include "src/core/lib/transport/error_utils.h"
40 #include "src/core/util/crash.h"
41 #include "src/core/util/host_port.h"
42 #include "src/core/util/string.h"
43 #include "src/core/util/thd.h"
44 #include "src/core/util/useful.h"
45
46 namespace grpc_core {
47 namespace {
48
49 class NativeDNSRequest {
50 public:
NativeDNSRequest(absl::string_view name,absl::string_view default_port,std::function<void (absl::StatusOr<std::vector<grpc_resolved_address>>)> on_done)51 NativeDNSRequest(
52 absl::string_view name, absl::string_view default_port,
53 std::function<void(absl::StatusOr<std::vector<grpc_resolved_address>>)>
54 on_done)
55 : name_(name), default_port_(default_port), on_done_(std::move(on_done)) {
56 GRPC_CLOSURE_INIT(&request_closure_, DoRequestThread, this, nullptr);
57 Executor::Run(&request_closure_, absl::OkStatus(), ExecutorType::RESOLVER);
58 }
59
60 private:
61 // Callback to be passed to grpc Executor to asynch-ify
62 // LookupHostnameBlocking
DoRequestThread(void * rp,grpc_error_handle)63 static void DoRequestThread(void* rp, grpc_error_handle /*error*/) {
64 NativeDNSRequest* r = static_cast<NativeDNSRequest*>(rp);
65 auto result =
66 GetDNSResolver()->LookupHostnameBlocking(r->name_, r->default_port_);
67 // running inline is safe since we've already been scheduled on the executor
68 r->on_done_(std::move(result));
69 delete r;
70 }
71
72 const std::string name_;
73 const std::string default_port_;
74 const std::function<void(absl::StatusOr<std::vector<grpc_resolved_address>>)>
75 on_done_;
76 grpc_closure request_closure_;
77 };
78
79 } // namespace
80
LookupHostname(std::function<void (absl::StatusOr<std::vector<grpc_resolved_address>>)> on_done,absl::string_view name,absl::string_view default_port,Duration,grpc_pollset_set *,absl::string_view)81 DNSResolver::TaskHandle NativeDNSResolver::LookupHostname(
82 std::function<void(absl::StatusOr<std::vector<grpc_resolved_address>>)>
83 on_done,
84 absl::string_view name, absl::string_view default_port,
85 Duration /* timeout */, grpc_pollset_set* /* interested_parties */,
86 absl::string_view /* name_server */) {
87 // self-deleting class
88 new NativeDNSRequest(name, default_port, std::move(on_done));
89 return kNullHandle;
90 }
91
92 absl::StatusOr<std::vector<grpc_resolved_address>>
LookupHostnameBlocking(absl::string_view name,absl::string_view default_port)93 NativeDNSResolver::LookupHostnameBlocking(absl::string_view name,
94 absl::string_view default_port) {
95 ExecCtx exec_ctx;
96 struct addrinfo hints;
97 struct addrinfo *result = nullptr, *resp;
98 int s;
99 size_t i;
100 grpc_error_handle err;
101 std::vector<grpc_resolved_address> addresses;
102 std::string host;
103 std::string port;
104 // parse name, splitting it into host and port parts
105 SplitHostPort(name, &host, &port);
106 if (host.empty()) {
107 err =
108 GRPC_ERROR_CREATE(absl::StrCat("unparsable host:port \"", name, "\""));
109 goto done;
110 }
111 if (port.empty()) {
112 if (default_port.empty()) {
113 err = GRPC_ERROR_CREATE(absl::StrCat("no port in name \"", name, "\""));
114 goto done;
115 }
116 port = std::string(default_port);
117 }
118 // Call getaddrinfo
119 memset(&hints, 0, sizeof(hints));
120 hints.ai_family = AF_UNSPEC; // ipv4 or ipv6
121 hints.ai_socktype = SOCK_STREAM; // stream socket
122 hints.ai_flags = AI_PASSIVE; // for wildcard IP address
123 GRPC_SCHEDULING_START_BLOCKING_REGION;
124 s = getaddrinfo(host.c_str(), port.c_str(), &hints, &result);
125 GRPC_SCHEDULING_END_BLOCKING_REGION;
126 if (s != 0) {
127 // Retry if well-known service name is recognized
128 const char* svc[][2] = {{"http", "80"}, {"https", "443"}};
129 for (i = 0; i < GPR_ARRAY_SIZE(svc); i++) {
130 if (port == svc[i][0]) {
131 GRPC_SCHEDULING_START_BLOCKING_REGION;
132 s = getaddrinfo(host.c_str(), svc[i][1], &hints, &result);
133 GRPC_SCHEDULING_END_BLOCKING_REGION;
134 break;
135 }
136 }
137 }
138 if (s != 0) {
139 err = absl::UnknownError(absl::StrCat(
140 "getaddrinfo(\"", name, "\"): ", gai_strerror(s), " (", s, ")"));
141 goto done;
142 }
143 // Success path: fill in addrs
144 for (resp = result; resp != nullptr; resp = resp->ai_next) {
145 grpc_resolved_address addr;
146 memcpy(&addr.addr, resp->ai_addr, resp->ai_addrlen);
147 addr.len = resp->ai_addrlen;
148 addresses.push_back(addr);
149 }
150 err = absl::OkStatus();
151 done:
152 if (result) {
153 freeaddrinfo(result);
154 }
155 if (err.ok()) {
156 return addresses;
157 }
158 auto error_result = grpc_error_to_absl_status(err);
159 return error_result;
160 }
161
LookupSRV(std::function<void (absl::StatusOr<std::vector<grpc_resolved_address>>)> on_resolved,absl::string_view,Duration,grpc_pollset_set *,absl::string_view)162 DNSResolver::TaskHandle NativeDNSResolver::LookupSRV(
163 std::function<void(absl::StatusOr<std::vector<grpc_resolved_address>>)>
164 on_resolved,
165 absl::string_view /* name */, Duration /* timeout */,
166 grpc_pollset_set* /* interested_parties */,
167 absl::string_view /* name_server */) {
168 grpc_event_engine::experimental::GetDefaultEventEngine()->Run([on_resolved] {
169 ApplicationCallbackExecCtx app_exec_ctx;
170 ExecCtx exec_ctx;
171 on_resolved(absl::UnimplementedError(
172 "The Native resolver does not support looking up SRV records"));
173 });
174 return {-1, -1};
175 };
176
LookupTXT(std::function<void (absl::StatusOr<std::string>)> on_resolved,absl::string_view,Duration,grpc_pollset_set *,absl::string_view)177 DNSResolver::TaskHandle NativeDNSResolver::LookupTXT(
178 std::function<void(absl::StatusOr<std::string>)> on_resolved,
179 absl::string_view /* name */, Duration /* timeout */,
180 grpc_pollset_set* /* interested_parties */,
181 absl::string_view /* name_server */) {
182 // Not supported
183 grpc_event_engine::experimental::GetDefaultEventEngine()->Run([on_resolved] {
184 ApplicationCallbackExecCtx app_exec_ctx;
185 ExecCtx exec_ctx;
186 on_resolved(absl::UnimplementedError(
187 "The Native resolver does not support looking up TXT records"));
188 });
189 return {-1, -1};
190 };
191
Cancel(TaskHandle)192 bool NativeDNSResolver::Cancel(TaskHandle /*handle*/) { return false; }
193
194 } // namespace grpc_core
195
196 #endif
197