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      1 /*
      2  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include "webrtc/p2p/base/stunserver.h"
     12 
     13 #include "webrtc/base/bytebuffer.h"
     14 #include "webrtc/base/logging.h"
     15 
     16 namespace cricket {
     17 
     18 StunServer::StunServer(rtc::AsyncUDPSocket* socket) : socket_(socket) {
     19   socket_->SignalReadPacket.connect(this, &StunServer::OnPacket);
     20 }
     21 
     22 StunServer::~StunServer() {
     23   socket_->SignalReadPacket.disconnect(this);
     24 }
     25 
     26 void StunServer::OnPacket(
     27     rtc::AsyncPacketSocket* socket, const char* buf, size_t size,
     28     const rtc::SocketAddress& remote_addr,
     29     const rtc::PacketTime& packet_time) {
     30   // Parse the STUN message; eat any messages that fail to parse.
     31   rtc::ByteBuffer bbuf(buf, size);
     32   StunMessage msg;
     33   if (!msg.Read(&bbuf)) {
     34     return;
     35   }
     36 
     37   // TODO: If unknown non-optional (<= 0x7fff) attributes are found, send a
     38   //       420 "Unknown Attribute" response.
     39 
     40   // Send the message to the appropriate handler function.
     41   switch (msg.type()) {
     42     case STUN_BINDING_REQUEST:
     43       OnBindingRequest(&msg, remote_addr);
     44       break;
     45 
     46     default:
     47       SendErrorResponse(msg, remote_addr, 600, "Operation Not Supported");
     48   }
     49 }
     50 
     51 void StunServer::OnBindingRequest(
     52     StunMessage* msg, const rtc::SocketAddress& remote_addr) {
     53   StunMessage response;
     54   GetStunBindReqponse(msg, remote_addr, &response);
     55   SendResponse(response, remote_addr);
     56 }
     57 
     58 void StunServer::SendErrorResponse(
     59     const StunMessage& msg, const rtc::SocketAddress& addr,
     60     int error_code, const char* error_desc) {
     61   StunMessage err_msg;
     62   err_msg.SetType(GetStunErrorResponseType(msg.type()));
     63   err_msg.SetTransactionID(msg.transaction_id());
     64 
     65   StunErrorCodeAttribute* err_code = StunAttribute::CreateErrorCode();
     66   err_code->SetCode(error_code);
     67   err_code->SetReason(error_desc);
     68   err_msg.AddAttribute(err_code);
     69 
     70   SendResponse(err_msg, addr);
     71 }
     72 
     73 void StunServer::SendResponse(
     74     const StunMessage& msg, const rtc::SocketAddress& addr) {
     75   rtc::ByteBuffer buf;
     76   msg.Write(&buf);
     77   rtc::PacketOptions options;
     78   if (socket_->SendTo(buf.Data(), buf.Length(), addr, options) < 0)
     79     LOG_ERR(LS_ERROR) << "sendto";
     80 }
     81 
     82 void StunServer::GetStunBindReqponse(StunMessage* request,
     83                                      const rtc::SocketAddress& remote_addr,
     84                                      StunMessage* response) const {
     85   response->SetType(STUN_BINDING_RESPONSE);
     86   response->SetTransactionID(request->transaction_id());
     87 
     88   // Tell the user the address that we received their request from.
     89   StunAddressAttribute* mapped_addr;
     90   if (!request->IsLegacy()) {
     91     mapped_addr = StunAttribute::CreateAddress(STUN_ATTR_MAPPED_ADDRESS);
     92   } else {
     93     mapped_addr = StunAttribute::CreateXorAddress(STUN_ATTR_XOR_MAPPED_ADDRESS);
     94   }
     95   mapped_addr->SetAddress(remote_addr);
     96   response->AddAttribute(mapped_addr);
     97 }
     98 
     99 }  // namespace cricket
    100