1 files changed, 104 insertions, 0 deletions
diff --git a/third_party/libwebrtc/p2p/base/stun_server.cc b/third_party/libwebrtc/p2p/base/stun_server.cc
new file mode 100644
index 0000000000..7827a0bb81
--- /dev/null
+++ b/third_party/libwebrtc/p2p/base/stun_server.cc
@@ -0,0 +1,104 @@
+/*
+ *  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