Repo created

TMessagesProj/jni/voip/webrtc/rtc_base/async_dns_resolver.cc

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+/*
+ *  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 <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "api/make_ref_counted.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/platform_thread.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<rtc::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<rtc::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) {
+      rtc::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 rtc::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 rtc::scoped_refptr<AsyncDnsResolver::State> Create() {
+    return rtc::make_ref_counted<AsyncDnsResolver::State>();
+  }
+
+  // Execute the passed function if the state is Active.
+  void Finish(absl::AnyInvocable<void()> function) {
+    webrtc::MutexLock lock(&mutex_);
+    if (status_ != Status::kActive) {
+      return;
+    }
+    status_ = Status::kFinished;
+    function();
+  }
+  void Kill() {
+    webrtc::MutexLock lock(&mutex_);
+    status_ = Status::kDead;
+  }
+
+ private:
+  webrtc::Mutex mutex_;
+  Status status_ RTC_GUARDED_BY(mutex_) = Status::kActive;
+};
+
+AsyncDnsResolver::AsyncDnsResolver() : state_(State::Create()) {}
+
+AsyncDnsResolver::~AsyncDnsResolver() {
+  state_->Kill();
+}
+
+void AsyncDnsResolver::Start(const rtc::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 rtc::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 = webrtc::TaskQueueBase::Current(),
+                          state = state_] {
+    std::vector<rtc::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)]() {
+      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
+  rtc::PlatformThread::SpawnDetached(std::move(thread_function),
+                                     "AsyncResolver");
+#endif
+}
+
+const AsyncDnsResolverResult& AsyncDnsResolver::result() const {
+  return result_;
+}
+
+bool AsyncDnsResolverResultImpl::GetResolvedAddress(
+    int family,
+    rtc::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