First step in providing a UdpTransportChannel.

webrtc/p2p/base/udptransportchannel.cc

+/*
+ *  Copyright 2016 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 "webrtc/p2p/base/udptransportchannel.h"
+
+#include <string>
+
+#include "webrtc/base/asyncudpsocket.h"
+#include "webrtc/base/asyncpacketsocket.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/base/physicalsocketserver.h"
+#include "webrtc/base/socketaddress.h"
+#include "webrtc/base/thread.h"
+#include "webrtc/base/thread_checker.h"
+#include "webrtc/p2p/base/basicpacketsocketfactory.h"
+#include "webrtc/p2p/base/packettransportinterface.h"
+
+namespace cricket {
+
+UdpTransportChannel::UdpTransportChannel(const std::string& transport_name)
+    : UdpTransportChannel(transport_name,
+                          rtc::Thread::Current()->socketserver()) {}
+
+UdpTransportChannel::UdpTransportChannel(const std::string& transport_name,
+                                         rtc::SocketServer* socket_server)
+    : transport_name_(transport_name), socket_server_(socket_server) {}
+
+UdpTransportChannel::~UdpTransportChannel() {
+  RTC_DCHECK_RUN_ON(&network_thread_checker_);
+}
+
+void UdpTransportChannel::OnSocketReadPacket(
+    rtc::AsyncPacketSocket* socket,
+    const char* data,
+    size_t len,
+    const rtc::SocketAddress& remote_addr,
+    const rtc::PacketTime& packet_time) {
+  // No thread_checker in high frequency network function.
+  SignalReadPacket(this, data, len, packet_time, 0);
+}
+
+void UdpTransportChannel::OnSocketSentPacket(rtc::AsyncPacketSocket* socket,
+                                             const rtc::SentPacket& packet) {
+  RTC_DCHECK_EQ(socket_.get(), socket);
+  SignalSentPacket(this, packet);
+}
+
+bool UdpTransportChannel::writable() const {
+  return state_ == State::CONNECTED;
+}
+
+int UdpTransportChannel::SendPacket(const char* data,
+                                    size_t len,
+                                    const rtc::PacketOptions& options,
+                                    int flags) {
+  // No thread_checker in high frequency network function.
+  if (!remote_parameters_) {
+    LOG(LS_WARNING) << "Remote parameters not set.";
+    send_error_ = ENOTCONN;
+    return -1;
+  }
+  const rtc::SocketAddress& remote_addr_ = *remote_parameters_;
+  int result = socket_->SendTo((const void*)data, len, remote_addr_, options);
+  if (result <= 0) {
+    LOG(LS_VERBOSE) << "SendPacket() " << result;
+  }
+  return result;
+}
+
+void UdpTransportChannel::Start() {
+  RTC_DCHECK_RUN_ON(&network_thread_checker_);
+  if (socket_) {
+    LOG(LS_WARNING) << "Local socket already allocated.";
+    return;
+  }
+  static constexpr uint16_t kMaxTries = 100;
+  static constexpr uint16_t kMinPortNumber = 2000;
+  // TODO(johan) provide configuration option for kMinPortNumber.
+  rtc::SocketAddress socket_addr("0.0.0.0", 0);
+  // TODO(johan): Replace BasicPacketSocketFactory by something that honors RFC
+  // 3550 Section 11 port number requirements like
+  // {port_{RTP} is even, port_{RTCP} := port{RTP} + 1}.
+  rtc::BasicPacketSocketFactory socket_factory(socket_server_);
+  socket_.reset(socket_factory.CreateUdpSocket(socket_addr, kMinPortNumber,
+                                               kMinPortNumber + kMaxTries));
+  if (socket_) {
+    local_parameters_ =
+        rtc::Optional<rtc::SocketAddress>(socket_->GetLocalAddress());
+    LOG(INFO) << "Created UDP socket with addr " << local_parameters_->ipaddr()
+              << " port " << local_parameters_->port() << ".";
+    socket_->SignalReadPacket.connect(this,
+                                      &UdpTransportChannel::OnSocketReadPacket);
+    socket_->SignalSentPacket.connect(this,
+                                      &UdpTransportChannel::OnSocketSentPacket);
+  } else {
+    LOG(INFO) << "Local socket allocation failure";
+  }
+  UpdateState();
+  return;
+}
+
+void UdpTransportChannel::UpdateState() {
+  RTC_DCHECK_RUN_ON(&network_thread_checker_);
+  RTC_DCHECK(!(local_parameters_ && !socket_));
+  RTC_DCHECK(!(!local_parameters_ && socket_));
+  if (!local_parameters_) {
+    SetState(State::INIT);
+  } else if (!remote_parameters_) {
+    SetState(State::CONNECTING);
+  } else {
+    SetState(State::CONNECTED);
+  }
+}
+
+void UdpTransportChannel::SetRemoteParameters(const rtc::SocketAddress& addr) {
+  RTC_DCHECK_RUN_ON(&network_thread_checker_);
+  if (!addr.IsComplete()) {
+    LOG(INFO) << "remote address not complete";
+    return;
+  }
+  // TODO(johan) check for ipv4, other settings.
+  remote_parameters_ = rtc::Optional<rtc::SocketAddress>(addr);
+  UpdateState();
+}
+
+void UdpTransportChannel::SetState(State state) {
+  RTC_DCHECK_RUN_ON(&network_thread_checker_);
+  if (state_ == state) {
+    return;
+  }
+  state_ = state;
+  if (state == State::CONNECTED) {
+    SignalWritableState(this);
+    SignalReadyToSend(this);
+  }
+}
+}  // namespace cricket