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