content/browser/renderer_host/p2p/socket_host_tcp.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/renderer_host/p2p/socket_host_tcp.h"
   6
   7 #include "base/location.h"
   8 #include "base/single_thread_task_runner.h"
   9 #include "base/sys_byteorder.h"
  10 #include "content/common/p2p_messages.h"
  11 #include "ipc/ipc_sender.h"
  12 #include "jingle/glue/fake_ssl_client_socket.h"
  13 #include "jingle/glue/proxy_resolving_client_socket.h"
  14 #include "net/base/io_buffer.h"
  15 #include "net/base/net_errors.h"
  16 #include "net/base/net_util.h"
  17 #include "net/socket/client_socket_factory.h"
  18 #include "net/socket/client_socket_handle.h"
  19 #include "net/socket/ssl_client_socket.h"
  20 #include "net/socket/tcp_client_socket.h"
  21 #include "net/url_request/url_request_context.h"
  22 #include "net/url_request/url_request_context_getter.h"
  23 #include "third_party/webrtc/base/asyncpacketsocket.h"
  24
  25 namespace {
  26
  27 typedef uint16 PacketLength;
  28 const int kPacketHeaderSize = sizeof(PacketLength);
  29 const int kReadBufferSize = 4096;
  30 const int kPacketLengthOffset = 2;
  31 const int kTurnChannelDataHeaderSize = 4;
  32 const int kRecvSocketBufferSize = 128 * 1024;
  33 const int kSendSocketBufferSize = 128 * 1024;
  34
  35 bool IsTlsClientSocket(content::P2PSocketType type) {
  36   return (type == content::P2P_SOCKET_STUN_TLS_CLIENT ||
  37           type == content::P2P_SOCKET_TLS_CLIENT);
  38 }
  39
  40 bool IsPseudoTlsClientSocket(content::P2PSocketType type) {
  41   return (type == content::P2P_SOCKET_SSLTCP_CLIENT ||
  42           type == content::P2P_SOCKET_STUN_SSLTCP_CLIENT);
  43 }
  44
  45 }  // namespace
  46
  47 namespace content {
  48
  49 P2PSocketHostTcpBase::P2PSocketHostTcpBase(
  50     IPC::Sender* message_sender,
  51     int socket_id,
  52     P2PSocketType type,
  53     net::URLRequestContextGetter* url_context)
  54     : P2PSocketHost(message_sender, socket_id, P2PSocketHost::TCP),
  55       write_pending_(false),
  56       connected_(false),
  57       type_(type),
  58       url_context_(url_context) {
  59 }
  60
  61 P2PSocketHostTcpBase::~P2PSocketHostTcpBase() {
  62   if (state_ == STATE_OPEN) {
  63     DCHECK(socket_.get());
  64     socket_.reset();
  65   }
  66 }
  67
  68 bool P2PSocketHostTcpBase::InitAccepted(const net::IPEndPoint& remote_address,
  69                                         net::StreamSocket* socket) {
  70   DCHECK(socket);
  71   DCHECK_EQ(state_, STATE_UNINITIALIZED);
  72
  73   remote_address_.ip_address = remote_address;
  74   // TODO(ronghuawu): Add FakeSSLServerSocket.
  75   socket_.reset(socket);
  76   state_ = STATE_OPEN;
  77   DoRead();
  78   return state_ != STATE_ERROR;
  79 }
  80
  81 bool P2PSocketHostTcpBase::Init(const net::IPEndPoint& local_address,
  82                                 const P2PHostAndIPEndPoint& remote_address) {
  83   DCHECK_EQ(state_, STATE_UNINITIALIZED);
  84
  85   remote_address_ = remote_address;
  86   state_ = STATE_CONNECTING;
  87
  88   net::HostPortPair dest_host_port_pair;
  89   // If there is no resolved address, let's try with domain name, assuming
  90   // socket layer will do the DNS resolve.
  91   if (remote_address.ip_address.address().empty()) {
  92     DCHECK(!remote_address.hostname.empty());
  93     dest_host_port_pair = net::HostPortPair(remote_address.hostname,
  94                                             remote_address.ip_address.port());
  95   } else {
  96     dest_host_port_pair = net::HostPortPair::FromIPEndPoint(
  97         remote_address.ip_address);
  98   }
  99
 100   // TODO(mallinath) - We are ignoring local_address altogether. We should
 101   // find a way to inject this into ProxyResolvingClientSocket. This could be
 102   // a problem on multi-homed host.
 103
 104   // The default SSLConfig is good enough for us for now.
 105   const net::SSLConfig ssl_config;
 106   socket_.reset(new jingle_glue::ProxyResolvingClientSocket(
 107                     NULL,     // Default socket pool provided by the net::Proxy.
 108                     url_context_,
 109                     ssl_config,
 110                     dest_host_port_pair));
 111
 112   int status = socket_->Connect(
 113       base::Bind(&P2PSocketHostTcpBase::OnConnected,
 114                  base::Unretained(this)));
 115   if (status != net::ERR_IO_PENDING) {
 116     // We defer execution of ProcessConnectDone instead of calling it
 117     // directly here as the caller may not expect an error/close to
 118     // happen here.  This is okay, as from the caller's point of view,
 119     // the connect always happens asynchronously.
 120     base::MessageLoop* message_loop = base::MessageLoop::current();
 121     CHECK(message_loop);
 122     message_loop->task_runner()->PostTask(
 123         FROM_HERE, base::Bind(&P2PSocketHostTcpBase::OnConnected,
 124                               base::Unretained(this), status));
 125   }
 126
 127   return state_ != STATE_ERROR;
 128 }
 129
 130 void P2PSocketHostTcpBase::OnError() {
 131   socket_.reset();
 132
 133   if (state_ == STATE_UNINITIALIZED || state_ == STATE_CONNECTING ||
 134       state_ == STATE_TLS_CONNECTING || state_ == STATE_OPEN) {
 135     message_sender_->Send(new P2PMsg_OnError(id_));
 136   }
 137
 138   state_ = STATE_ERROR;
 139 }
 140
 141 void P2PSocketHostTcpBase::OnConnected(int result) {
 142   DCHECK_EQ(state_, STATE_CONNECTING);
 143   DCHECK_NE(result, net::ERR_IO_PENDING);
 144
 145   if (result != net::OK) {
 146     LOG(WARNING) << "Error from connecting socket, result=" << result;
 147     OnError();
 148     return;
 149   }
 150
 151   if (IsTlsClientSocket(type_)) {
 152     state_ = STATE_TLS_CONNECTING;
 153     StartTls();
 154   } else if (IsPseudoTlsClientSocket(type_)) {
 155     scoped_ptr<net::StreamSocket> transport_socket = socket_.Pass();
 156     socket_.reset(
 157         new jingle_glue::FakeSSLClientSocket(transport_socket.Pass()));
 158     state_ = STATE_TLS_CONNECTING;
 159     int status = socket_->Connect(
 160         base::Bind(&P2PSocketHostTcpBase::ProcessTlsSslConnectDone,
 161                    base::Unretained(this)));
 162     if (status != net::ERR_IO_PENDING) {
 163       ProcessTlsSslConnectDone(status);
 164     }
 165   } else {
 166     // If we are not doing TLS, we are ready to send data now.
 167     // In case of TLS, SignalConnect will be sent only after TLS handshake is
 168     // successfull. So no buffering will be done at socket handlers if any
 169     // packets sent before that by the application.
 170     OnOpen();
 171   }
 172 }
 173
 174 void P2PSocketHostTcpBase::StartTls() {
 175   DCHECK_EQ(state_, STATE_TLS_CONNECTING);
 176   DCHECK(socket_.get());
 177
 178   scoped_ptr<net::ClientSocketHandle> socket_handle(
 179       new net::ClientSocketHandle());
 180   socket_handle->SetSocket(socket_.Pass());
 181
 182   net::SSLClientSocketContext context;
 183   context.cert_verifier = url_context_->GetURLRequestContext()->cert_verifier();
 184   context.transport_security_state =
 185       url_context_->GetURLRequestContext()->transport_security_state();
 186   DCHECK(context.transport_security_state);
 187
 188   // Default ssl config.
 189   const net::SSLConfig ssl_config;
 190   net::HostPortPair dest_host_port_pair;
 191
 192   // Calling net::HostPortPair::FromIPEndPoint will crash if the IP address is
 193   // empty.
 194   if (!remote_address_.ip_address.address().empty()) {
 195       net::HostPortPair::FromIPEndPoint(remote_address_.ip_address);
 196   } else {
 197     dest_host_port_pair.set_port(remote_address_.ip_address.port());
 198   }
 199   if (!remote_address_.hostname.empty())
 200     dest_host_port_pair.set_host(remote_address_.hostname);
 201
 202   net::ClientSocketFactory* socket_factory =
 203       net::ClientSocketFactory::GetDefaultFactory();
 204   DCHECK(socket_factory);
 205
 206   socket_ = socket_factory->CreateSSLClientSocket(
 207       socket_handle.Pass(), dest_host_port_pair, ssl_config, context);
 208   int status = socket_->Connect(
 209       base::Bind(&P2PSocketHostTcpBase::ProcessTlsSslConnectDone,
 210                  base::Unretained(this)));
 211
 212   if (status != net::ERR_IO_PENDING) {
 213     ProcessTlsSslConnectDone(status);
 214   }
 215 }
 216
 217 void P2PSocketHostTcpBase::ProcessTlsSslConnectDone(int status) {
 218   DCHECK_NE(status, net::ERR_IO_PENDING);
 219   DCHECK_EQ(state_, STATE_TLS_CONNECTING);
 220   if (status != net::OK) {
 221     LOG(WARNING) << "Error from connecting TLS socket, status=" << status;
 222     OnError();
 223     return;
 224   }
 225   OnOpen();
 226 }
 227
 228 void P2PSocketHostTcpBase::OnOpen() {
 229   state_ = STATE_OPEN;
 230   // Setting socket send and receive buffer size.
 231   if (net::OK != socket_->SetReceiveBufferSize(kRecvSocketBufferSize)) {
 232     LOG(WARNING) << "Failed to set socket receive buffer size to "
 233                  << kRecvSocketBufferSize;
 234   }
 235
 236   if (net::OK != socket_->SetSendBufferSize(kSendSocketBufferSize)) {
 237     LOG(WARNING) << "Failed to set socket send buffer size to "
 238                  << kSendSocketBufferSize;
 239   }
 240
 241   if (!DoSendSocketCreateMsg())
 242     return;
 243
 244   DCHECK_EQ(state_, STATE_OPEN);
 245   DoRead();
 246 }
 247
 248 bool P2PSocketHostTcpBase::DoSendSocketCreateMsg() {
 249   DCHECK(socket_.get());
 250
 251   net::IPEndPoint local_address;
 252   int result = socket_->GetLocalAddress(&local_address);
 253   if (result < 0) {
 254     LOG(ERROR) << "P2PSocketHostTcpBase::OnConnected: unable to get local"
 255                << " address: " << result;
 256     OnError();
 257     return false;
 258   }
 259
 260   VLOG(1) << "Local address: " << local_address.ToString();
 261
 262   net::IPEndPoint remote_address;
 263
 264   // GetPeerAddress returns ERR_NAME_NOT_RESOLVED if the socket is connected
 265   // through a proxy.
 266   result = socket_->GetPeerAddress(&remote_address);
 267   if (result < 0 && result != net::ERR_NAME_NOT_RESOLVED) {
 268     LOG(ERROR) << "P2PSocketHostTcpBase::OnConnected: unable to get peer"
 269                << " address: " << result;
 270     OnError();
 271     return false;
 272   }
 273
 274   if (!remote_address.address().empty()) {
 275     VLOG(1) << "Remote address: " << remote_address.ToString();
 276     if (remote_address_.ip_address.address().empty()) {
 277       // Save |remote_address| if address is empty.
 278       remote_address_.ip_address = remote_address;
 279     }
 280   } else {
 281     VLOG(1) << "Remote address is unknown since connection is proxied";
 282   }
 283
 284   // If we are not doing TLS, we are ready to send data now.
 285   // In case of TLS SignalConnect will be sent only after TLS handshake is
 286   // successful. So no buffering will be done at socket handlers if any
 287   // packets sent before that by the application.
 288   message_sender_->Send(new P2PMsg_OnSocketCreated(
 289       id_, local_address, remote_address));
 290   return true;
 291 }
 292
 293 void P2PSocketHostTcpBase::DoRead() {
 294   int result;
 295   do {
 296     if (!read_buffer_.get()) {
 297       read_buffer_ = new net::GrowableIOBuffer();
 298       read_buffer_->SetCapacity(kReadBufferSize);
 299     } else if (read_buffer_->RemainingCapacity() < kReadBufferSize) {
 300       // Make sure that we always have at least kReadBufferSize of
 301       // remaining capacity in the read buffer. Normally all packets
 302       // are smaller than kReadBufferSize, so this is not really
 303       // required.
 304       read_buffer_->SetCapacity(read_buffer_->capacity() + kReadBufferSize -
 305                                 read_buffer_->RemainingCapacity());
 306     }
 307     result = socket_->Read(
 308         read_buffer_.get(),
 309         read_buffer_->RemainingCapacity(),
 310         base::Bind(&P2PSocketHostTcp::OnRead, base::Unretained(this)));
 311     DidCompleteRead(result);
 312   } while (result > 0);
 313 }
 314
 315 void P2PSocketHostTcpBase::OnRead(int result) {
 316   DidCompleteRead(result);
 317   if (state_ == STATE_OPEN) {
 318     DoRead();
 319   }
 320 }
 321
 322 void P2PSocketHostTcpBase::OnPacket(const std::vector<char>& data) {
 323   if (!connected_) {
 324     P2PSocketHost::StunMessageType type;
 325     bool stun = GetStunPacketType(&*data.begin(), data.size(), &type);
 326     if (stun && IsRequestOrResponse(type)) {
 327       connected_ = true;
 328     } else if (!stun || type == STUN_DATA_INDICATION) {
 329       LOG(ERROR) << "Received unexpected data packet from "
 330                  << remote_address_.ip_address.ToString()
 331                  << " before STUN binding is finished. "
 332                  << "Terminating connection.";
 333       OnError();
 334       return;
 335     }
 336   }
 337
 338   message_sender_->Send(new P2PMsg_OnDataReceived(
 339       id_, remote_address_.ip_address, data, base::TimeTicks::Now()));
 340
 341   if (dump_incoming_rtp_packet_)
 342     DumpRtpPacket(&data[0], data.size(), true);
 343 }
 344
 345 // Note: dscp is not actually used on TCP sockets as this point,
 346 // but may be honored in the future.
 347 void P2PSocketHostTcpBase::Send(const net::IPEndPoint& to,
 348                                 const std::vector<char>& data,
 349                                 const rtc::PacketOptions& options,
 350                                 uint64 packet_id) {
 351   if (!socket_) {
 352     // The Send message may be sent after the an OnError message was
 353     // sent by hasn't been processed the renderer.
 354     return;
 355   }
 356
 357   if (!(to == remote_address_.ip_address)) {
 358     // Renderer should use this socket only to send data to |remote_address_|.
 359     NOTREACHED();
 360     OnError();
 361     return;
 362   }
 363
 364   if (!connected_) {
 365     P2PSocketHost::StunMessageType type = P2PSocketHost::StunMessageType();
 366     bool stun = GetStunPacketType(&*data.begin(), data.size(), &type);
 367     if (!stun || type == STUN_DATA_INDICATION) {
 368       LOG(ERROR) << "Page tried to send a data packet to " << to.ToString()
 369                  << " before STUN binding is finished.";
 370       OnError();
 371       return;
 372     }
 373   }
 374
 375   DoSend(to, data, options);
 376 }
 377
 378 void P2PSocketHostTcpBase::WriteOrQueue(
 379     scoped_refptr<net::DrainableIOBuffer>& buffer) {
 380   IncrementTotalSentPackets();
 381   if (write_buffer_.get()) {
 382     write_queue_.push(buffer);
 383     IncrementDelayedPackets();
 384     IncrementDelayedBytes(buffer->size());
 385     return;
 386   }
 387
 388   write_buffer_ = buffer;
 389   DoWrite();
 390 }
 391
 392 void P2PSocketHostTcpBase::DoWrite() {
 393   while (write_buffer_.get() && state_ == STATE_OPEN && !write_pending_) {
 394     int result = socket_->Write(
 395         write_buffer_.get(),
 396         write_buffer_->BytesRemaining(),
 397         base::Bind(&P2PSocketHostTcp::OnWritten, base::Unretained(this)));
 398     HandleWriteResult(result);
 399   }
 400 }
 401
 402 void P2PSocketHostTcpBase::OnWritten(int result) {
 403   DCHECK(write_pending_);
 404   DCHECK_NE(result, net::ERR_IO_PENDING);
 405
 406   write_pending_ = false;
 407   HandleWriteResult(result);
 408   DoWrite();
 409 }
 410
 411 void P2PSocketHostTcpBase::HandleWriteResult(int result) {
 412   DCHECK(write_buffer_.get());
 413   if (result >= 0) {
 414     write_buffer_->DidConsume(result);
 415     if (write_buffer_->BytesRemaining() == 0) {
 416       message_sender_->Send(
 417           new P2PMsg_OnSendComplete(id_, P2PSendPacketMetrics()));
 418       if (write_queue_.empty()) {
 419         write_buffer_ = NULL;
 420       } else {
 421         write_buffer_ = write_queue_.front();
 422         write_queue_.pop();
 423         // Update how many bytes are still waiting to be sent.
 424         DecrementDelayedBytes(write_buffer_->size());
 425       }
 426     }
 427   } else if (result == net::ERR_IO_PENDING) {
 428     write_pending_ = true;
 429   } else {
 430     LOG(ERROR) << "Error when sending data in TCP socket: " << result;
 431     OnError();
 432   }
 433 }
 434
 435 P2PSocketHost* P2PSocketHostTcpBase::AcceptIncomingTcpConnection(
 436     const net::IPEndPoint& remote_address, int id) {
 437   NOTREACHED();
 438   OnError();
 439   return NULL;
 440 }
 441
 442 void P2PSocketHostTcpBase::DidCompleteRead(int result) {
 443   DCHECK_EQ(state_, STATE_OPEN);
 444
 445   if (result == net::ERR_IO_PENDING) {
 446     return;
 447   } else if (result < 0) {
 448     LOG(ERROR) << "Error when reading from TCP socket: " << result;
 449     OnError();
 450     return;
 451   } else if (result == 0) {
 452     LOG(WARNING) << "Remote peer has shutdown TCP socket.";
 453     OnError();
 454     return;
 455   }
 456
 457   read_buffer_->set_offset(read_buffer_->offset() + result);
 458   char* head = read_buffer_->StartOfBuffer();  // Purely a convenience.
 459   int pos = 0;
 460   while (pos <= read_buffer_->offset() && state_ == STATE_OPEN) {
 461     int consumed = ProcessInput(head + pos, read_buffer_->offset() - pos);
 462     if (!consumed)
 463       break;
 464     pos += consumed;
 465   }
 466   // We've consumed all complete packets from the buffer; now move any remaining
 467   // bytes to the head of the buffer and set offset to reflect this.
 468   if (pos && pos <= read_buffer_->offset()) {
 469     memmove(head, head + pos, read_buffer_->offset() - pos);
 470     read_buffer_->set_offset(read_buffer_->offset() - pos);
 471   }
 472 }
 473
 474 bool P2PSocketHostTcpBase::SetOption(P2PSocketOption option, int value) {
 475   DCHECK_EQ(STATE_OPEN, state_);
 476   switch (option) {
 477     case P2P_SOCKET_OPT_RCVBUF:
 478       return socket_->SetReceiveBufferSize(value) == net::OK;
 479     case P2P_SOCKET_OPT_SNDBUF:
 480       return socket_->SetSendBufferSize(value) == net::OK;
 481     case P2P_SOCKET_OPT_DSCP:
 482       return false;  // For TCP sockets DSCP setting is not available.
 483     default:
 484       NOTREACHED();
 485       return false;
 486   }
 487 }
 488
 489 P2PSocketHostTcp::P2PSocketHostTcp(IPC::Sender* message_sender,
 490                                    int socket_id,
 491                                    P2PSocketType type,
 492                                    net::URLRequestContextGetter* url_context)
 493     : P2PSocketHostTcpBase(message_sender, socket_id, type, url_context) {
 494   DCHECK(type == P2P_SOCKET_TCP_CLIENT ||
 495          type == P2P_SOCKET_SSLTCP_CLIENT ||
 496          type == P2P_SOCKET_TLS_CLIENT);
 497 }
 498
 499 P2PSocketHostTcp::~P2PSocketHostTcp() {
 500 }
 501
 502 int P2PSocketHostTcp::ProcessInput(char* input, int input_len) {
 503   if (input_len < kPacketHeaderSize)
 504     return 0;
 505   int packet_size = base::NetToHost16(*reinterpret_cast<uint16*>(input));
 506   if (input_len < packet_size + kPacketHeaderSize)
 507     return 0;
 508
 509   int consumed = kPacketHeaderSize;
 510   char* cur = input + consumed;
 511   std::vector<char> data(cur, cur + packet_size);
 512   OnPacket(data);
 513   consumed += packet_size;
 514   return consumed;
 515 }
 516
 517 void P2PSocketHostTcp::DoSend(const net::IPEndPoint& to,
 518                               const std::vector<char>& data,
 519                               const rtc::PacketOptions& options) {
 520   int size = kPacketHeaderSize + data.size();
 521   scoped_refptr<net::DrainableIOBuffer> buffer =
 522       new net::DrainableIOBuffer(new net::IOBuffer(size), size);
 523   *reinterpret_cast<uint16*>(buffer->data()) = base::HostToNet16(data.size());
 524   memcpy(buffer->data() + kPacketHeaderSize, &data[0], data.size());
 525
 526   packet_processing_helpers::ApplyPacketOptions(
 527       buffer->data() + kPacketHeaderSize,
 528       buffer->BytesRemaining() - kPacketHeaderSize,
 529       options, 0);
 530
 531   WriteOrQueue(buffer);
 532 }
 533
 534 // P2PSocketHostStunTcp
 535 P2PSocketHostStunTcp::P2PSocketHostStunTcp(
 536     IPC::Sender* message_sender,
 537     int socket_id,
 538     P2PSocketType type,
 539     net::URLRequestContextGetter* url_context)
 540     : P2PSocketHostTcpBase(message_sender, socket_id, type, url_context) {
 541   DCHECK(type == P2P_SOCKET_STUN_TCP_CLIENT ||
 542          type == P2P_SOCKET_STUN_SSLTCP_CLIENT ||
 543          type == P2P_SOCKET_STUN_TLS_CLIENT);
 544 }
 545
 546 P2PSocketHostStunTcp::~P2PSocketHostStunTcp() {
 547 }
 548
 549 int P2PSocketHostStunTcp::ProcessInput(char* input, int input_len) {
 550   if (input_len < kPacketHeaderSize + kPacketLengthOffset)
 551     return 0;
 552
 553   int pad_bytes;
 554   int packet_size = GetExpectedPacketSize(
 555       input, input_len, &pad_bytes);
 556
 557   if (input_len < packet_size + pad_bytes)
 558     return 0;
 559
 560   // We have a complete packet. Read through it.
 561   int consumed = 0;
 562   char* cur = input;
 563   std::vector<char> data(cur, cur + packet_size);
 564   OnPacket(data);
 565   consumed += packet_size;
 566   consumed += pad_bytes;
 567   return consumed;
 568 }
 569
 570 void P2PSocketHostStunTcp::DoSend(const net::IPEndPoint& to,
 571                                   const std::vector<char>& data,
 572                                   const rtc::PacketOptions& options) {
 573   // Each packet is expected to have header (STUN/TURN ChannelData), where
 574   // header contains message type and and length of message.
 575   if (data.size() < kPacketHeaderSize + kPacketLengthOffset) {
 576     NOTREACHED();
 577     OnError();
 578     return;
 579   }
 580
 581   int pad_bytes;
 582   size_t expected_len = GetExpectedPacketSize(
 583       &data[0], data.size(), &pad_bytes);
 584
 585   // Accepts only complete STUN/TURN packets.
 586   if (data.size() != expected_len) {
 587     NOTREACHED();
 588     OnError();
 589     return;
 590   }
 591
 592   // Add any pad bytes to the total size.
 593   int size = data.size() + pad_bytes;
 594
 595   scoped_refptr<net::DrainableIOBuffer> buffer =
 596       new net::DrainableIOBuffer(new net::IOBuffer(size), size);
 597   memcpy(buffer->data(), &data[0], data.size());
 598
 599   packet_processing_helpers::ApplyPacketOptions(
 600       buffer->data(), data.size(), options, 0);
 601
 602   if (pad_bytes) {
 603     char padding[4] = {0};
 604     DCHECK_LE(pad_bytes, 4);
 605     memcpy(buffer->data() + data.size(), padding, pad_bytes);
 606   }
 607   WriteOrQueue(buffer);
 608
 609   if (dump_outgoing_rtp_packet_)
 610     DumpRtpPacket(buffer->data(), data.size(), false);
 611 }
 612
 613 int P2PSocketHostStunTcp::GetExpectedPacketSize(
 614     const char* data, int len, int* pad_bytes) {
 615   DCHECK_LE(kTurnChannelDataHeaderSize, len);
 616   // Both stun and turn had length at offset 2.
 617   int packet_size = base::NetToHost16(*reinterpret_cast<const uint16*>(
 618       data + kPacketLengthOffset));
 619
 620   // Get packet type (STUN or TURN).
 621   uint16 msg_type = base::NetToHost16(*reinterpret_cast<const uint16*>(data));
 622
 623   *pad_bytes = 0;
 624   // Add heder length to packet length.
 625   if ((msg_type & 0xC000) == 0) {
 626     packet_size += kStunHeaderSize;
 627   } else {
 628     packet_size += kTurnChannelDataHeaderSize;
 629     // Calculate any padding if present.
 630     if (packet_size % 4)
 631       *pad_bytes = 4 - packet_size % 4;
 632   }
 633   return packet_size;
 634 }
 635
 636 }  // namespace content