src/media/cast/net/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/net/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
  23 namespace {
  24 const int kMaxPacketSize = 1500;
  25
  26 bool IsEmpty(const net::IPEndPoint& addr) {
  27   net::IPAddressNumber empty_addr(addr.address().size());
  28   return std::equal(
  29              empty_addr.begin(), empty_addr.end(), addr.address().begin()) &&
  30          !addr.port();
  31 }
  32
  33 bool IsEqual(const net::IPEndPoint& addr1, const net::IPEndPoint& addr2) {
  34   return addr1.port() == addr2.port() && std::equal(addr1.address().begin(),
  35                                                     addr1.address().end(),
  36                                                     addr2.address().begin());
  37 }
  38 }  // namespace
  39
  40 UdpTransport::UdpTransport(
  41     net::NetLog* net_log,
  42     const scoped_refptr<base::SingleThreadTaskRunner>& io_thread_proxy,
  43     const net::IPEndPoint& local_end_point,
  44     const net::IPEndPoint& remote_end_point,
  45     const CastTransportStatusCallback& status_callback)
  46     : io_thread_proxy_(io_thread_proxy),
  47       local_addr_(local_end_point),
  48       remote_addr_(remote_end_point),
  49       udp_socket_(new net::UDPSocket(net::DatagramSocket::DEFAULT_BIND,
  50                                      net::RandIntCallback(),
  51                                      net_log,
  52                                      net::NetLog::Source())),
  53       send_pending_(false),
  54       receive_pending_(false),
  55       client_connected_(false),
  56       next_dscp_value_(net::DSCP_NO_CHANGE),
  57       status_callback_(status_callback),
  58       bytes_sent_(0),
  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 =
 120           udp_socket_->RecvFrom(recv_buf_.get(),
 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       receive_pending_ = false;
 136       return;
 137     }
 138
 139     // Confirm the packet has come from the expected remote address; otherwise,
 140     // ignore it.  If this is the first packet being received and no remote
 141     // address has been set, set the remote address and expect all future
 142     // packets to come from the same one.
 143     // TODO(hubbe): We should only do this if the caller used a valid ssrc.
 144     if (IsEmpty(remote_addr_)) {
 145       remote_addr_ = recv_addr_;
 146       VLOG(1) << "Setting remote address from first received packet: "
 147               << remote_addr_.ToString();
 148     } else if (!IsEqual(remote_addr_, recv_addr_)) {
 149       VLOG(1) << "Ignoring packet received from an unrecognized address: "
 150               << recv_addr_.ToString() << ".";
 151       length_or_status = net::ERR_IO_PENDING;
 152       continue;
 153     }
 154
 155     next_packet_->resize(length_or_status);
 156     packet_receiver_.Run(next_packet_.Pass());
 157     length_or_status = net::ERR_IO_PENDING;
 158   }
 159 }
 160
 161 bool UdpTransport::SendPacket(PacketRef packet, const base::Closure& cb) {
 162   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
 163
 164   // Increase byte count no matter the packet was sent or dropped.
 165   bytes_sent_ += packet->data.size();
 166
 167   DCHECK(!send_pending_);
 168   if (send_pending_) {
 169     VLOG(1) << "Cannot send because of pending IO.";
 170     return true;
 171   }
 172
 173   if (next_dscp_value_ != net::DSCP_NO_CHANGE) {
 174     int result = udp_socket_->SetDiffServCodePoint(next_dscp_value_);
 175     if (result != net::OK) {
 176       VLOG(1) << "Unable to set DSCP: " << next_dscp_value_
 177               << " to socket; Error: " << result;
 178     }
 179
 180     if (result != net::ERR_SOCKET_NOT_CONNECTED) {
 181       // Don't change DSCP in next send.
 182       next_dscp_value_ = net::DSCP_NO_CHANGE;
 183     }
 184   }
 185
 186   scoped_refptr<net::IOBuffer> buf =
 187       new net::WrappedIOBuffer(reinterpret_cast<char*>(&packet->data.front()));
 188
 189   int result;
 190   base::Callback<void(int)> callback = base::Bind(&UdpTransport::OnSent,
 191                                                   weak_factory_.GetWeakPtr(),
 192                                                   buf,
 193                                                   packet,
 194                                                   cb);
 195   if (client_connected_) {
 196     // If we called Connect() before we must call Write() instead of
 197     // SendTo(). Otherwise on some platforms we might get
 198     // ERR_SOCKET_IS_CONNECTED.
 199     result = udp_socket_->Write(
 200         buf.get(), static_cast<int>(packet->data.size()), callback);
 201   } else if (!IsEmpty(remote_addr_)) {
 202     result = udp_socket_->SendTo(buf.get(),
 203                                  static_cast<int>(packet->data.size()),
 204                                  remote_addr_,
 205                                  callback);
 206   } else {
 207     VLOG(1) << "Failed to send packet; socket is neither bound nor "
 208             << "connected.";
 209     return true;
 210   }
 211
 212   if (result == net::ERR_IO_PENDING) {
 213     send_pending_ = true;
 214     return false;
 215   }
 216   OnSent(buf, packet, base::Closure(), result);
 217   return true;
 218 }
 219
 220 int64 UdpTransport::GetBytesSent() {
 221   return bytes_sent_;
 222 }
 223
 224 void UdpTransport::OnSent(const scoped_refptr<net::IOBuffer>& buf,
 225                           PacketRef packet,
 226                           const base::Closure& cb,
 227                           int result) {
 228   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
 229
 230   send_pending_ = false;
 231   if (result < 0) {
 232     VLOG(1) << "Failed to send packet: " << result << ".";
 233   }
 234   ScheduleReceiveNextPacket();
 235
 236   if (!cb.is_null()) {
 237     cb.Run();
 238   }
 239 }
 240
 241 }  // namespace cast
 242 }  // namespace media