src/media/cast/transport/transport/udp_transport.cc

   1 // Copyright 2014 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 "media/cast/transport/transport/udp_transport.h"
   6
   7 #include <algorithm>
   8 #include <string>
   9
  10 #include "base/bind.h"
  11 #include "base/logging.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/message_loop/message_loop.h"
  15 #include "base/rand_util.h"
  16 #include "net/base/io_buffer.h"
  17 #include "net/base/net_errors.h"
  18 #include "net/base/rand_callback.h"
  19
  20 namespace media {
  21 namespace cast {
  22 namespace transport {
  23
  24 namespace {
  25 const int kMaxPacketSize = 1500;
  26
  27 bool IsEmpty(const net::IPEndPoint& addr) {
  28   net::IPAddressNumber empty_addr(addr.address().size());
  29   return std::equal(
  30              empty_addr.begin(), empty_addr.end(), addr.address().begin()) &&
  31          !addr.port();
  32 }
  33
  34 bool IsEqual(const net::IPEndPoint& addr1, const net::IPEndPoint& addr2) {
  35   return addr1.port() == addr2.port() && std::equal(addr1.address().begin(),
  36                                                     addr1.address().end(),
  37                                                     addr2.address().begin());
  38 }
  39 }  // namespace
  40
  41 UdpTransport::UdpTransport(
  42     net::NetLog* net_log,
  43     const scoped_refptr<base::SingleThreadTaskRunner>& io_thread_proxy,
  44     const net::IPEndPoint& local_end_point,
  45     const net::IPEndPoint& remote_end_point,
  46     const CastTransportStatusCallback& status_callback)
  47     : io_thread_proxy_(io_thread_proxy),
  48       local_addr_(local_end_point),
  49       remote_addr_(remote_end_point),
  50       udp_socket_(new net::UDPSocket(net::DatagramSocket::DEFAULT_BIND,
  51                                      net::RandIntCallback(),
  52                                      net_log,
  53                                      net::NetLog::Source())),
  54       send_pending_(false),
  55       receive_pending_(false),
  56       client_connected_(false),
  57       next_dscp_value_(net::DSCP_NO_CHANGE),
  58       status_callback_(status_callback),
  59       weak_factory_(this) {
  60   DCHECK(!IsEmpty(local_end_point) || !IsEmpty(remote_end_point));
  61 }
  62
  63 UdpTransport::~UdpTransport() {}
  64
  65 void UdpTransport::StartReceiving(
  66     const PacketReceiverCallback& packet_receiver) {
  67   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
  68
  69   packet_receiver_ = packet_receiver;
  70   udp_socket_->AllowAddressReuse();
  71   udp_socket_->SetMulticastLoopbackMode(true);
  72   if (!IsEmpty(local_addr_)) {
  73     if (udp_socket_->Bind(local_addr_) < 0) {
  74       status_callback_.Run(TRANSPORT_SOCKET_ERROR);
  75       LOG(ERROR) << "Failed to bind local address.";
  76       return;
  77     }
  78   } else if (!IsEmpty(remote_addr_)) {
  79     if (udp_socket_->Connect(remote_addr_) < 0) {
  80       status_callback_.Run(TRANSPORT_SOCKET_ERROR);
  81       LOG(ERROR) << "Failed to connect to remote address.";
  82       return;
  83     }
  84     client_connected_ = true;
  85   } else {
  86     NOTREACHED() << "Either local or remote address has to be defined.";
  87   }
  88
  89   ScheduleReceiveNextPacket();
  90 }
  91
  92 void UdpTransport::SetDscp(net::DiffServCodePoint dscp) {
  93   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
  94   next_dscp_value_ = dscp;
  95 }
  96
  97 void UdpTransport::ScheduleReceiveNextPacket() {
  98   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
  99   if (!packet_receiver_.is_null() && !receive_pending_) {
 100     receive_pending_ = true;
 101     io_thread_proxy_->PostTask(FROM_HERE,
 102                                base::Bind(&UdpTransport::ReceiveNextPacket,
 103                                           weak_factory_.GetWeakPtr(),
 104                                           net::ERR_IO_PENDING));
 105   }
 106 }
 107
 108 void UdpTransport::ReceiveNextPacket(int length_or_status) {
 109   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
 110
 111   // Loop while UdpSocket is delivering data synchronously.  When it responds
 112   // with a "pending" status, break and expect this method to be called back in
 113   // the future when a packet is ready.
 114   while (true) {
 115     if (length_or_status == net::ERR_IO_PENDING) {
 116       next_packet_.reset(new Packet(kMaxPacketSize));
 117       recv_buf_ = new net::WrappedIOBuffer(
 118           reinterpret_cast<char*>(&next_packet_->front()));
 119       length_or_status = udp_socket_->RecvFrom(
 120           recv_buf_,
 121           kMaxPacketSize,
 122           &recv_addr_,
 123           base::Bind(&UdpTransport::ReceiveNextPacket,
 124                      weak_factory_.GetWeakPtr()));
 125       if (length_or_status == net::ERR_IO_PENDING) {
 126         receive_pending_ = true;
 127         return;
 128       }
 129     }
 130
 131     // Note: At this point, either a packet is ready or an error has occurred.
 132     if (length_or_status < 0) {
 133       VLOG(1) << "Failed to receive packet: Status code is "
 134               << length_or_status;
 135       status_callback_.Run(TRANSPORT_SOCKET_ERROR);
 136       receive_pending_ = false;
 137       return;
 138     }
 139
 140     // Confirm the packet has come from the expected remote address; otherwise,
 141     // ignore it.  If this is the first packet being received and no remote
 142     // address has been set, set the remote address and expect all future
 143     // packets to come from the same one.
 144     // TODO(hubbe): We should only do this if the caller used a valid ssrc.
 145     if (IsEmpty(remote_addr_)) {
 146       remote_addr_ = recv_addr_;
 147       VLOG(1) << "Setting remote address from first received packet: "
 148               << remote_addr_.ToString();
 149     } else if (!IsEqual(remote_addr_, recv_addr_)) {
 150       VLOG(1) << "Ignoring packet received from an unrecognized address: "
 151               << recv_addr_.ToString() << ".";
 152       length_or_status = net::ERR_IO_PENDING;
 153       continue;
 154     }
 155
 156     next_packet_->resize(length_or_status);
 157     packet_receiver_.Run(next_packet_.Pass());
 158     length_or_status = net::ERR_IO_PENDING;
 159   }
 160 }
 161
 162 bool UdpTransport::SendPacket(PacketRef packet, const base::Closure& cb) {
 163   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
 164
 165   DCHECK(!send_pending_);
 166   if (send_pending_) {
 167     VLOG(1) << "Cannot send because of pending IO.";
 168     return true;
 169   }
 170
 171   if (next_dscp_value_ != net::DSCP_NO_CHANGE) {
 172     int result = udp_socket_->SetDiffServCodePoint(next_dscp_value_);
 173     if (result != net::OK) {
 174       LOG(ERROR) << "Unable to set DSCP: " << next_dscp_value_
 175                  << " to socket; Error: " << result;
 176     }
 177     // Don't change DSCP in next send.
 178     next_dscp_value_ = net::DSCP_NO_CHANGE;
 179   }
 180
 181   scoped_refptr<net::IOBuffer> buf =
 182       new net::WrappedIOBuffer(reinterpret_cast<char*>(&packet->data.front()));
 183
 184   int result;
 185   base::Callback<void(int)> callback = base::Bind(&UdpTransport::OnSent,
 186                                                   weak_factory_.GetWeakPtr(),
 187                                                   buf,
 188                                                   packet,
 189                                                   cb);
 190   if (client_connected_) {
 191     // If we called Connect() before we must call Write() instead of
 192     // SendTo(). Otherwise on some platforms we might get
 193     // ERR_SOCKET_IS_CONNECTED.
 194     result = udp_socket_->Write(buf,
 195                                 static_cast<int>(packet->data.size()),
 196                                 callback);
 197   } else if (!IsEmpty(remote_addr_)) {
 198     result = udp_socket_->SendTo(buf,
 199                                  static_cast<int>(packet->data.size()),
 200                                  remote_addr_,
 201                                  callback);
 202   } else {
 203     return true;
 204   }
 205
 206   if (result == net::ERR_IO_PENDING) {
 207     send_pending_ = true;
 208     return false;
 209   } else if (result < 0) {
 210     LOG(ERROR) << "Failed to send packet: " << result << ".";
 211     status_callback_.Run(TRANSPORT_SOCKET_ERROR);
 212     return true;
 213   } else {
 214     // Successful send, re-start reading if needed.
 215     ScheduleReceiveNextPacket();
 216     return true;
 217   }
 218 }
 219
 220 void UdpTransport::OnSent(const scoped_refptr<net::IOBuffer>& buf,
 221                           PacketRef packet,
 222                           const base::Closure& cb,
 223                           int result) {
 224   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
 225
 226   send_pending_ = false;
 227   if (result < 0) {
 228     LOG(ERROR) << "Failed to send packet: " << result << ".";
 229     status_callback_.Run(TRANSPORT_SOCKET_ERROR);
 230   } else {
 231     // Successful send, re-start reading if needed.
 232     ScheduleReceiveNextPacket();
 233   }
 234
 235   if (!cb.is_null()) {
 236     cb.Run();
 237   }
 238 }
 239
 240 }  // namespace transport
 241 }  // namespace cast
 242 }  // namespace media