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      1 /*
      2  * libjingle
      3  * Copyright 2004--2005, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include "talk/p2p/base/stunserver.h"
     29 
     30 #include "webrtc/base/bytebuffer.h"
     31 #include "webrtc/base/logging.h"
     32 
     33 namespace cricket {
     34 
     35 StunServer::StunServer(rtc::AsyncUDPSocket* socket) : socket_(socket) {
     36   socket_->SignalReadPacket.connect(this, &StunServer::OnPacket);
     37 }
     38 
     39 StunServer::~StunServer() {
     40   socket_->SignalReadPacket.disconnect(this);
     41 }
     42 
     43 void StunServer::OnPacket(
     44     rtc::AsyncPacketSocket* socket, const char* buf, size_t size,
     45     const rtc::SocketAddress& remote_addr,
     46     const rtc::PacketTime& packet_time) {
     47   // Parse the STUN message; eat any messages that fail to parse.
     48   rtc::ByteBuffer bbuf(buf, size);
     49   StunMessage msg;
     50   if (!msg.Read(&bbuf)) {
     51     return;
     52   }
     53 
     54   // TODO: If unknown non-optional (<= 0x7fff) attributes are found, send a
     55   //       420 "Unknown Attribute" response.
     56 
     57   // Send the message to the appropriate handler function.
     58   switch (msg.type()) {
     59     case STUN_BINDING_REQUEST:
     60       OnBindingRequest(&msg, remote_addr);
     61       break;
     62 
     63     default:
     64       SendErrorResponse(msg, remote_addr, 600, "Operation Not Supported");
     65   }
     66 }
     67 
     68 void StunServer::OnBindingRequest(
     69     StunMessage* msg, const rtc::SocketAddress& remote_addr) {
     70   StunMessage response;
     71   response.SetType(STUN_BINDING_RESPONSE);
     72   response.SetTransactionID(msg->transaction_id());
     73 
     74   // Tell the user the address that we received their request from.
     75   StunAddressAttribute* mapped_addr;
     76   if (!msg->IsLegacy()) {
     77     mapped_addr = StunAttribute::CreateAddress(STUN_ATTR_MAPPED_ADDRESS);
     78   } else {
     79     mapped_addr = StunAttribute::CreateXorAddress(STUN_ATTR_XOR_MAPPED_ADDRESS);
     80   }
     81   mapped_addr->SetAddress(remote_addr);
     82   response.AddAttribute(mapped_addr);
     83 
     84   SendResponse(response, remote_addr);
     85 }
     86 
     87 void StunServer::SendErrorResponse(
     88     const StunMessage& msg, const rtc::SocketAddress& addr,
     89     int error_code, const char* error_desc) {
     90   StunMessage err_msg;
     91   err_msg.SetType(GetStunErrorResponseType(msg.type()));
     92   err_msg.SetTransactionID(msg.transaction_id());
     93 
     94   StunErrorCodeAttribute* err_code = StunAttribute::CreateErrorCode();
     95   err_code->SetCode(error_code);
     96   err_code->SetReason(error_desc);
     97   err_msg.AddAttribute(err_code);
     98 
     99   SendResponse(err_msg, addr);
    100 }
    101 
    102 void StunServer::SendResponse(
    103     const StunMessage& msg, const rtc::SocketAddress& addr) {
    104   rtc::ByteBuffer buf;
    105   msg.Write(&buf);
    106   rtc::PacketOptions options;
    107   if (socket_->SendTo(buf.Data(), buf.Length(), addr, options) < 0)
    108     LOG_ERR(LS_ERROR) << "sendto";
    109 }
    110 
    111 }  // namespace cricket
    112