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/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "p2p/base/stun_server.h"
#include <string>
#include <utility>
#include "absl/strings/string_view.h"
#include "rtc_base/byte_buffer.h"
#include "rtc_base/logging.h"
namespace cricket {
StunServer::StunServer(rtc::AsyncUDPSocket* socket) : socket_(socket) {
socket_->SignalReadPacket.connect(this, &StunServer::OnPacket);
}
StunServer::~StunServer() {
socket_->SignalReadPacket.disconnect(this);
}
void StunServer::OnPacket(rtc::AsyncPacketSocket* socket,
const char* buf,
size_t size,
const rtc::SocketAddress& remote_addr,
const int64_t& /* packet_time_us */) {
// Parse the STUN message; eat any messages that fail to parse.
rtc::ByteBufferReader bbuf(buf, size);
StunMessage msg;
if (!msg.Read(&bbuf)) {
return;
}
// TODO(?): If unknown non-optional (<= 0x7fff) attributes are found, send a
// 420 "Unknown Attribute" response.
// Send the message to the appropriate handler function.
switch (msg.type()) {
case STUN_BINDING_REQUEST:
OnBindingRequest(&msg, remote_addr);
break;
default:
SendErrorResponse(msg, remote_addr, 600, "Operation Not Supported");
}
}
void StunServer::OnBindingRequest(StunMessage* msg,
const rtc::SocketAddress& remote_addr) {
StunMessage response(STUN_BINDING_RESPONSE, msg->transaction_id());
GetStunBindResponse(msg, remote_addr, &response);
SendResponse(response, remote_addr);
}
void StunServer::SendErrorResponse(const StunMessage& msg,
const rtc::SocketAddress& addr,
int error_code,
absl::string_view error_desc) {
StunMessage err_msg(GetStunErrorResponseType(msg.type()),
msg.transaction_id());
auto err_code = StunAttribute::CreateErrorCode();
err_code->SetCode(error_code);
err_code->SetReason(std::string(error_desc));
err_msg.AddAttribute(std::move(err_code));
SendResponse(err_msg, addr);
}
void StunServer::SendResponse(const StunMessage& msg,
const rtc::SocketAddress& addr) {
rtc::ByteBufferWriter buf;
msg.Write(&buf);
rtc::PacketOptions options;
if (socket_->SendTo(buf.Data(), buf.Length(), addr, options) < 0)
RTC_LOG_ERR(LS_ERROR) << "sendto";
}
void StunServer::GetStunBindResponse(StunMessage* message,
const rtc::SocketAddress& remote_addr,
StunMessage* response) const {
RTC_DCHECK_EQ(response->type(), STUN_BINDING_RESPONSE);
RTC_DCHECK_EQ(response->transaction_id(), message->transaction_id());
// Tell the user the address that we received their message from.
std::unique_ptr<StunAddressAttribute> mapped_addr;
if (message->IsLegacy()) {
mapped_addr = StunAttribute::CreateAddress(STUN_ATTR_MAPPED_ADDRESS);
} else {
mapped_addr = StunAttribute::CreateXorAddress(STUN_ATTR_XOR_MAPPED_ADDRESS);
}
mapped_addr->SetAddress(remote_addr);
response->AddAttribute(std::move(mapped_addr));
}
} // namespace cricket
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