1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
/*
* Copyright 2023 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/async_dns_resolver.h"
#include <string>
#include <utility>
#include <vector>
#include "absl/functional/any_invocable.h"
#include "absl/strings/string_view.h"
#include "api/async_dns_resolver.h"
#include "api/make_ref_counted.h"
#include "api/ref_counted_base.h"
#include "api/scoped_refptr.h"
#include "api/sequence_checker.h"
#include "api/task_queue/pending_task_safety_flag.h"
#include "api/task_queue/task_queue_base.h"
#include "rtc_base/checks.h"
#include "rtc_base/ip_address.h"
#include "rtc_base/net_helpers.h"
#include "rtc_base/platform_thread.h"
#include "rtc_base/socket_address.h"
#include "rtc_base/synchronization/mutex.h"
#include "rtc_base/thread_annotations.h"
#if defined(WEBRTC_MAC) || defined(WEBRTC_IOS)
#include <dispatch/dispatch.h>
#endif
namespace webrtc {
namespace {
#ifdef __native_client__
int ResolveHostname(absl::string_view hostname,
int family,
std::vector<IPAddress>* addresses) {
RTC_DCHECK_NOTREACHED();
RTC_LOG(LS_WARNING) << "ResolveHostname() is not implemented for NaCl";
return -1;
}
#else // notdef(__native_client__)
int ResolveHostname(absl::string_view hostname,
int family,
std::vector<IPAddress>& addresses) {
addresses.clear();
struct addrinfo* result = nullptr;
struct addrinfo hints = {0};
hints.ai_family = family;
// `family` here will almost always be AF_UNSPEC, because `family` comes from
// AsyncResolver::addr_.family(), which comes from a SocketAddress constructed
// with a hostname. When a SocketAddress is constructed with a hostname, its
// family is AF_UNSPEC. However, if someday in the future we construct
// a SocketAddress with both a hostname and a family other than AF_UNSPEC,
// then it would be possible to get a specific family value here.
// The behavior of AF_UNSPEC is roughly "get both ipv4 and ipv6", as
// documented by the various operating systems:
// Linux: http://man7.org/linux/man-pages/man3/getaddrinfo.3.html
// Windows: https://msdn.microsoft.com/en-us/library/windows/desktop/
// ms738520(v=vs.85).aspx
// Mac: https://developer.apple.com/legacy/library/documentation/Darwin/
// Reference/ManPages/man3/getaddrinfo.3.html
// Android (source code, not documentation):
// https://android.googlesource.com/platform/bionic/+/
// 7e0bfb511e85834d7c6cb9631206b62f82701d60/libc/netbsd/net/getaddrinfo.c#1657
hints.ai_flags = AI_ADDRCONFIG;
int ret =
getaddrinfo(std::string(hostname).c_str(), nullptr, &hints, &result);
if (ret != 0) {
return ret;
}
struct addrinfo* cursor = result;
for (; cursor; cursor = cursor->ai_next) {
if (family == AF_UNSPEC || cursor->ai_family == family) {
IPAddress ip;
if (IPFromAddrInfo(cursor, &ip)) {
addresses.push_back(ip);
}
}
}
freeaddrinfo(result);
return 0;
}
#endif // !__native_client__
// Special task posting for Mac/iOS
#if defined(WEBRTC_MAC) || defined(WEBRTC_IOS)
void GlobalGcdRunTask(void* context) {
std::unique_ptr<absl::AnyInvocable<void() &&>> task(
static_cast<absl::AnyInvocable<void() &&>*>(context));
std::move (*task)();
}
// Post a task into the system-defined global concurrent queue.
void PostTaskToGlobalQueue(
std::unique_ptr<absl::AnyInvocable<void() &&>> task) {
dispatch_async_f(
dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
task.release(), &GlobalGcdRunTask);
}
#endif // defined(WEBRTC_MAC) || defined(WEBRTC_IOS)
} // namespace
class AsyncDnsResolver::State : public RefCountedBase {
public:
enum class Status {
kActive, // Running request, or able to be passed one
kFinished, // Request has finished processing
kDead // The owning AsyncDnsResolver has been deleted
};
static scoped_refptr<AsyncDnsResolver::State> Create() {
return make_ref_counted<AsyncDnsResolver::State>();
}
// Execute the passed function if the state is Active.
void Finish(absl::AnyInvocable<void()> function) {
MutexLock lock(&mutex_);
if (status_ != Status::kActive) {
return;
}
status_ = Status::kFinished;
function();
}
void Kill() {
MutexLock lock(&mutex_);
status_ = Status::kDead;
}
private:
Mutex mutex_;
Status status_ RTC_GUARDED_BY(mutex_) = Status::kActive;
};
AsyncDnsResolver::AsyncDnsResolver() : state_(State::Create()) {}
AsyncDnsResolver::~AsyncDnsResolver() {
state_->Kill();
}
void AsyncDnsResolver::Start(const SocketAddress& addr,
absl::AnyInvocable<void()> callback) {
Start(addr, addr.family(), std::move(callback));
}
// Start address resolution of the hostname in `addr` matching `family`.
void AsyncDnsResolver::Start(const SocketAddress& addr,
int family,
absl::AnyInvocable<void()> callback) {
RTC_DCHECK_RUN_ON(&result_.sequence_checker_);
result_.addr_ = addr;
callback_ = std::move(callback);
auto thread_function = [this, addr, family, flag = safety_.flag(),
caller_task_queue = TaskQueueBase::Current(),
state = state_] {
std::vector<IPAddress> addresses;
int error = ResolveHostname(addr.hostname(), family, addresses);
// We assume that the caller task queue is still around if the
// AsyncDnsResolver has not been destroyed.
state->Finish([this, error, flag, caller_task_queue,
addresses = std::move(addresses)]() mutable {
caller_task_queue->PostTask(
SafeTask(flag, [this, error, addresses = std::move(addresses)]() {
RTC_DCHECK_RUN_ON(&result_.sequence_checker_);
result_.addresses_ = addresses;
result_.error_ = error;
callback_();
}));
});
};
#if defined(WEBRTC_MAC) || defined(WEBRTC_IOS)
PostTaskToGlobalQueue(
std::make_unique<absl::AnyInvocable<void() &&>>(thread_function));
#else
PlatformThread::SpawnDetached(std::move(thread_function), "AsyncResolver");
#endif
}
const AsyncDnsResolverResult& AsyncDnsResolver::result() const {
return result_;
}
bool AsyncDnsResolverResultImpl::GetResolvedAddress(int family,
SocketAddress* addr) const {
RTC_DCHECK_RUN_ON(&sequence_checker_);
RTC_DCHECK(addr);
if (error_ != 0 || addresses_.empty())
return false;
*addr = addr_;
for (const auto& address : addresses_) {
if (family == address.family()) {
addr->SetResolvedIP(address);
return true;
}
}
return false;
}
int AsyncDnsResolverResultImpl::GetError() const {
RTC_DCHECK_RUN_ON(&sequence_checker_);
return error_;
}
} // namespace webrtc
|
