1 files changed, 657 insertions, 0 deletions
diff --git a/kopete/protocols/jabber/jingle/libjingle/talk/p2p/base/relayserver.cpp b/kopete/protocols/jabber/jingle/libjingle/talk/p2p/base/relayserver.cpp
new file mode 100644
index 00000000..bb52a1d5
--- /dev/null
+++ b/kopete/protocols/jabber/jingle/libjingle/talk/p2p/base/relayserver.cpp
@@ -0,0 +1,657 @@
+/*
+ * libjingle
+ * Copyright 2004--2005, Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice, 
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products 
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "talk/p2p/base/relayserver.h"
+#include "talk/p2p/base/helpers.h"
+#include <algorithm>
+#include <cassert>
+#include <cstring>
+#include <iostream>
+
+#ifdef POSIX
+extern "C" {
+#include <errno.h>
+}
+#endif // POSIX
+
+namespace cricket {
+
+// By default, we require a ping every 90 seconds.
+const int MAX_LIFETIME = 15 * 60 * 1000;
+
+// The number of bytes in each of the usernames we use.
+const uint32 USERNAME_LENGTH = 16;
+
+// Calls SendTo on the given socket and logs any bad results.
+void Send(AsyncPacketSocket* socket, const char* bytes, size_t size,
+          const SocketAddress& addr) {
+  int result = socket->SendTo(bytes, size, addr);
+  if (result < int(size)) {
+    std::cerr << "SendTo wrote only " << result << " of " << int(size)
+              << " bytes" << std::endl;
+  } else if (result < 0) {
+    std::cerr << "SendTo: " << std::strerror(errno) << std::endl;
+  }
+}
+
+// Sends the given STUN message on the given socket.
+void SendStun(const StunMessage& msg,
+              AsyncPacketSocket* socket,
+              const SocketAddress& addr) {
+  ByteBuffer buf;
+  msg.Write(&buf);
+  Send(socket, buf.Data(), buf.Length(), addr);
+}
+
+// Constructs a STUN error response and sends it on the given socket.
+void SendStunError(const StunMessage& msg, AsyncPacketSocket* socket,
+                   const SocketAddress& remote_addr, int error_code,
+                   const char* error_desc, const std::string& magic_cookie) {
+
+  StunMessage err_msg;
+  err_msg.SetType(GetStunErrorResponseType(msg.type()));
+  err_msg.SetTransactionID(msg.transaction_id());
+
+  StunByteStringAttribute* magic_cookie_attr =
+      StunAttribute::CreateByteString(cricket::STUN_ATTR_MAGIC_COOKIE);
+  if (magic_cookie.size() == 0)
+    magic_cookie_attr->CopyBytes(cricket::STUN_MAGIC_COOKIE_VALUE, 4);
+  else
+    magic_cookie_attr->CopyBytes(magic_cookie.c_str(), magic_cookie.size());
+  err_msg.AddAttribute(magic_cookie_attr);
+
+  StunErrorCodeAttribute* err_code = StunAttribute::CreateErrorCode();
+  err_code->SetErrorClass(error_code / 100);
+  err_code->SetNumber(error_code % 100);
+  err_code->SetReason(error_desc);
+  err_msg.AddAttribute(err_code);
+
+  SendStun(err_msg, socket, remote_addr);
+}
+
+RelayServer::RelayServer(Thread* thread) : thread_(thread) {
+}
+
+RelayServer::~RelayServer() {
+  for (unsigned i = 0; i < internal_sockets_.size(); i++)
+    delete internal_sockets_[i];
+  for (unsigned i = 0; i < external_sockets_.size(); i++)
+    delete external_sockets_[i];
+}
+
+void RelayServer::AddInternalSocket(AsyncPacketSocket* socket) {
+  assert(internal_sockets_.end() ==
+      std::find(internal_sockets_.begin(), internal_sockets_.end(), socket));
+  internal_sockets_.push_back(socket);
+  socket->SignalReadPacket.connect(this, &RelayServer::OnInternalPacket);
+}
+
+void RelayServer::RemoveInternalSocket(AsyncPacketSocket* socket) {
+  SocketList::iterator iter =
+      std::find(internal_sockets_.begin(), internal_sockets_.end(), socket);
+  assert(iter != internal_sockets_.end());
+  internal_sockets_.erase(iter);
+  socket->SignalReadPacket.disconnect(this);
+}
+
+void RelayServer::AddExternalSocket(AsyncPacketSocket* socket) {
+  assert(external_sockets_.end() ==
+      std::find(external_sockets_.begin(), external_sockets_.end(), socket));
+  external_sockets_.push_back(socket);
+  socket->SignalReadPacket.connect(this, &RelayServer::OnExternalPacket);
+}
+
+void RelayServer::RemoveExternalSocket(AsyncPacketSocket* socket) {
+  SocketList::iterator iter =
+      std::find(external_sockets_.begin(), external_sockets_.end(), socket);
+  assert(iter != external_sockets_.end());
+  external_sockets_.erase(iter);
+  socket->SignalReadPacket.disconnect(this);
+}
+
+void RelayServer::OnInternalPacket(
+    const char* bytes, size_t size, const SocketAddress& remote_addr,
+    AsyncPacketSocket* socket) {
+
+  // Get the address of the connection we just received on.
+  SocketAddressPair ap(remote_addr, socket->GetLocalAddress());
+  assert(!ap.destination().IsAny());
+
+  // If this did not come from an existing connection, it should be a STUN
+  // allocate request.
+  ConnectionMap::iterator piter = connections_.find(ap);
+  if (piter == connections_.end()) {
+    HandleStunAllocate(bytes, size, ap, socket);
+    return;
+  }
+
+  RelayServerConnection* int_conn = piter->second;
+
+  // Handle STUN requests to the server itself.
+  if (int_conn->binding()->HasMagicCookie(bytes, size)) {
+    HandleStun(int_conn, bytes, size);
+    return;
+  }
+
+  // Otherwise, this is a non-wrapped packet that we are to forward.  Make sure
+  // that this connection has been locked.  (Otherwise, we would not know what
+  // address to forward to.)
+  if (!int_conn->locked()) {
+    std::cerr << "Dropping packet: connection not locked" << std::endl;
+    return;
+  }
+
+  // Forward this to the destination address into the connection.
+  RelayServerConnection* ext_conn = int_conn->binding()->GetExternalConnection(
+      int_conn->default_destination());
+  if (ext_conn) {
+    // TODO: Check the HMAC.
+    ext_conn->Send(bytes, size);
+  } else {
+    // This happens very often and is not an error.
+    //std::cerr << "Dropping packet: no external connection" << std::endl;
+  }
+}
+
+void RelayServer::OnExternalPacket(
+    const char* bytes, size_t size, const SocketAddress& remote_addr,
+    AsyncPacketSocket* socket) {
+
+  // Get the address of the connection we just received on.
+  SocketAddressPair ap(remote_addr, socket->GetLocalAddress());
+  assert(!ap.destination().IsAny());
+
+  // If this connection already exists, then forward the traffic.
+  ConnectionMap::iterator piter = connections_.find(ap);
+  if (piter != connections_.end()) {
+    // TODO: Check the HMAC.
+    RelayServerConnection* ext_conn = piter->second;
+    RelayServerConnection* int_conn =
+        ext_conn->binding()->GetInternalConnection(
+            ext_conn->addr_pair().source());
+    assert(int_conn);
+    int_conn->Send(bytes, size, ext_conn->addr_pair().source());
+    return;
+  }
+
+  // The first packet should always be a STUN / TURN packet.  If it isn't, then
+  // we should just ignore this packet.
+  StunMessage msg;
+  ByteBuffer buf = ByteBuffer(bytes, size);
+  if (!msg.Read(&buf)) {
+    std::cerr << "Dropping packet: first packet not STUN" << std::endl;
+    return;
+  }
+
+  // The initial packet should have a username (which identifies the binding).
+  const StunByteStringAttribute* username_attr =
+      msg.GetByteString(STUN_ATTR_USERNAME);
+  if (!username_attr) {
+    std::cerr << "Dropping packet: no username" << std::endl;
+    return;
+  }
+
+  uint32 length = _min(uint32(username_attr->length()), USERNAME_LENGTH);
+  std::string username(username_attr->bytes(), length);
+  // TODO: Check the HMAC.
+
+  // The binding should already be present.
+  BindingMap::iterator biter = bindings_.find(username);
+  if (biter == bindings_.end()) {
+    // TODO: Turn this back on.  This is the sign of a client bug.
+    //std::cerr << "Dropping packet: no binding with username" << std::endl;
+    return;
+  }
+
+  // Add this authenticted connection to the binding.
+  RelayServerConnection* ext_conn =
+      new RelayServerConnection(biter->second, ap, socket);
+  ext_conn->binding()->AddExternalConnection(ext_conn);
+  AddConnection(ext_conn);
+
+  // We always know where external packets should be forwarded, so we can lock
+  // them from the beginning.
+  ext_conn->Lock();
+
+  // Send this message on the appropriate internal connection.
+  RelayServerConnection* int_conn = ext_conn->binding()->GetInternalConnection(
+      ext_conn->addr_pair().source());
+  assert(int_conn);
+  int_conn->Send(bytes, size, ext_conn->addr_pair().source());
+}
+
+bool RelayServer::HandleStun(
+    const char* bytes, size_t size, const SocketAddress& remote_addr,
+    AsyncPacketSocket* socket, std::string* username, StunMessage* msg) {
+
+  // Parse this into a stun message.
+  ByteBuffer buf = ByteBuffer(bytes, size);
+  if (!msg->Read(&buf)) {
+    SendStunError(*msg, socket, remote_addr, 400, "Bad Request", "");
+    return false;
+  }
+
+  // The initial packet should have a username (which identifies the binding).
+  const StunByteStringAttribute* username_attr =
+      msg->GetByteString(STUN_ATTR_USERNAME);
+  if (!username_attr) {
+    SendStunError(*msg, socket, remote_addr, 432, "Missing Username", "");
+    return false;
+  }
+
+  // Record the username if requested.
+  if (username)
+    username->append(username_attr->bytes(), username_attr->length());
+
+  // TODO: Check for unknown attributes (<= 0x7fff)
+
+  return true;
+}
+
+void RelayServer::HandleStunAllocate(
+    const char* bytes, size_t size, const SocketAddressPair& ap,
+    AsyncPacketSocket* socket) {
+
+  // Make sure this is a valid STUN request.
+  StunMessage request;
+  std::string username;
+  if (!HandleStun(bytes, size, ap.source(), socket, &username, &request))
+    return;
+
+  // Make sure this is a an allocate request.
+  if (request.type() != STUN_ALLOCATE_REQUEST) {
+    SendStunError(request,
+                  socket,
+                  ap.source(),
+                  600,
+                  "Operation Not Supported",
+                  "");
+    return;
+  }
+
+  // TODO: Check the HMAC.
+
+  // Find or create the binding for this username.
+
+  RelayServerBinding* binding;
+
+  BindingMap::iterator biter = bindings_.find(username);
+  if (biter != bindings_.end()) {
+
+    binding = biter->second;
+
+  } else {
+
+    // NOTE: In the future, bindings will be created by the bot only.  This
+    //       else-branch will then disappear.
+
+    // Compute the appropriate lifetime for this binding.
+    uint32 lifetime = MAX_LIFETIME;
+    const StunUInt32Attribute* lifetime_attr =
+        request.GetUInt32(STUN_ATTR_LIFETIME);
+    if (lifetime_attr)
+      lifetime = _min(lifetime, lifetime_attr->value() * 1000);
+
+    binding = new RelayServerBinding(this, username, "0", lifetime);
+    binding->SignalTimeout.connect(this, &RelayServer::OnTimeout);
+    bindings_[username] = binding;
+
+    std::cout << "Added new binding: " << bindings_.size() << " total" << std::endl;
+  }
+
+  // Add this connection to the binding.  It starts out unlocked.
+  RelayServerConnection* int_conn =
+      new RelayServerConnection(binding, ap, socket);
+  binding->AddInternalConnection(int_conn);
+  AddConnection(int_conn);
+
+  // Now that we have a connection, this other method takes over.
+  HandleStunAllocate(int_conn, request);
+}
+
+void RelayServer::HandleStun(
+    RelayServerConnection* int_conn, const char* bytes, size_t size) {
+
+  // Make sure this is a valid STUN request.
+  StunMessage request;
+  std::string username;
+  if (!HandleStun(bytes, size, int_conn->addr_pair().source(),
+                  int_conn->socket(), &username, &request))
+    return;
+
+  // Make sure the username is the one were were expecting.
+  if (username != int_conn->binding()->username()) {
+    int_conn->SendStunError(request, 430, "Stale Credentials");
+    return;
+  }
+
+  // TODO: Check the HMAC.
+
+  // Send this request to the appropriate handler.
+  if (request.type() == STUN_SEND_REQUEST)
+    HandleStunSend(int_conn, request);
+  else if (request.type() == STUN_ALLOCATE_REQUEST)
+    HandleStunAllocate(int_conn, request);
+  else
+    int_conn->SendStunError(request, 600, "Operation Not Supported");
+}
+
+void RelayServer::HandleStunAllocate(
+    RelayServerConnection* int_conn, const StunMessage& request) {
+
+  // Create a response message that includes an address with which external
+  // clients can communicate.
+
+  StunMessage response;
+  response.SetType(STUN_ALLOCATE_RESPONSE);
+  response.SetTransactionID(request.transaction_id());
+
+  StunByteStringAttribute* magic_cookie_attr =
+      StunAttribute::CreateByteString(cricket::STUN_ATTR_MAGIC_COOKIE);
+  magic_cookie_attr->CopyBytes(int_conn->binding()->magic_cookie().c_str(),
+                               int_conn->binding()->magic_cookie().size());
+  response.AddAttribute(magic_cookie_attr);
+
+  size_t index = rand() % external_sockets_.size();
+  SocketAddress ext_addr = external_sockets_[index]->GetLocalAddress();
+
+  StunAddressAttribute* addr_attr =
+      StunAttribute::CreateAddress(STUN_ATTR_MAPPED_ADDRESS);
+  addr_attr->SetFamily(1);
+  addr_attr->SetIP(ext_addr.ip());
+  addr_attr->SetPort(ext_addr.port());
+  response.AddAttribute(addr_attr);
+
+  StunUInt32Attribute* res_lifetime_attr =
+      StunAttribute::CreateUInt32(STUN_ATTR_LIFETIME);
+  res_lifetime_attr->SetValue(int_conn->binding()->lifetime() / 1000);
+  response.AddAttribute(res_lifetime_attr);
+
+  // TODO: Support transport-prefs (preallocate RTCP port).
+  // TODO: Support bandwidth restrictions.
+  // TODO: Add message integrity check.
+
+  // Send a response to the caller.
+  int_conn->SendStun(response);
+}
+
+void RelayServer::HandleStunSend(
+    RelayServerConnection* int_conn, const StunMessage& request) {
+
+  const StunAddressAttribute* addr_attr =
+      request.GetAddress(STUN_ATTR_DESTINATION_ADDRESS);
+  if (!addr_attr) {
+    int_conn->SendStunError(request, 400, "Bad Request");
+    return;
+  }
+
+  const StunByteStringAttribute* data_attr =
+      request.GetByteString(STUN_ATTR_DATA);
+  if (!data_attr) {
+    int_conn->SendStunError(request, 400, "Bad Request");
+    return;
+  }
+
+  SocketAddress ext_addr(addr_attr->ip(), addr_attr->port());
+  RelayServerConnection* ext_conn =
+      int_conn->binding()->GetExternalConnection(ext_addr);
+  if (!ext_conn) {
+    // This happens very often and is not an error.
+    //std::cerr << "Dropping packet: no external connection" << std::endl;
+    return;
+  }
+
+  ext_conn->Send(data_attr->bytes(), data_attr->length());
+
+  const StunUInt32Attribute* options_attr =
+      request.GetUInt32(STUN_ATTR_OPTIONS);
+  if (options_attr && (options_attr->value() & 0x01 != 0)) {
+    int_conn->set_default_destination(ext_addr);
+    int_conn->Lock();
+
+    StunMessage response;
+    response.SetType(STUN_SEND_RESPONSE);
+    response.SetTransactionID(request.transaction_id());
+
+    StunByteStringAttribute* magic_cookie_attr =
+        StunAttribute::CreateByteString(cricket::STUN_ATTR_MAGIC_COOKIE);
+    magic_cookie_attr->CopyBytes(int_conn->binding()->magic_cookie().c_str(),
+                                 int_conn->binding()->magic_cookie().size());
+    response.AddAttribute(magic_cookie_attr);
+
+    StunUInt32Attribute* options2_attr =
+      StunAttribute::CreateUInt32(cricket::STUN_ATTR_OPTIONS);
+    options2_attr->SetValue(0x01);
+    response.AddAttribute(options2_attr);
+    
+    int_conn->SendStun(response);
+  }
+}
+
+void RelayServer::AddConnection(RelayServerConnection* conn) {
+  assert(connections_.find(conn->addr_pair()) == connections_.end());
+  connections_[conn->addr_pair()] = conn;
+}
+
+void RelayServer::RemoveConnection(RelayServerConnection* conn) {
+  ConnectionMap::iterator iter = connections_.find(conn->addr_pair());
+  assert(iter != connections_.end());
+  connections_.erase(iter);
+}
+
+void RelayServer::RemoveBinding(RelayServerBinding* binding) {
+  BindingMap::iterator iter = bindings_.find(binding->username());
+  assert(iter != bindings_.end());
+  bindings_.erase(iter);
+
+  std::cout << "Removed a binding: " << bindings_.size() << " remaining" << std::endl;
+}
+
+void RelayServer::OnTimeout(RelayServerBinding* binding) {
+  // This call will result in all of the necessary clean-up.
+  delete binding;
+}
+
+RelayServerConnection::RelayServerConnection(
+    RelayServerBinding* binding, const SocketAddressPair& addrs,
+    AsyncPacketSocket* socket)
+  : binding_(binding), addr_pair_(addrs), socket_(socket), locked_(false) {
+
+  // The creation of a new connection constitutes a use of the binding.
+  binding_->NoteUsed();
+}
+
+RelayServerConnection::~RelayServerConnection() {
+  // Remove this connection from the server's map (if it exists there).
+  binding_->server()->RemoveConnection(this);
+}
+
+void RelayServerConnection::Send(const char* data, size_t size) {
+  // Note that the binding has been used again.
+  binding_->NoteUsed();
+
+  cricket::Send(socket_, data, size, addr_pair_.source());
+}
+
+void RelayServerConnection::Send(
+    const char* data, size_t size, const SocketAddress& from_addr) {
+  // If the from address is known to the client, we don't need to send it.
+  if (locked() && (from_addr == default_dest_)) {
+    Send(data, size);
+    return;
+  }
+
+  // Wrap the given data in a data-indication packet.
+
+  StunMessage msg;
+  msg.SetType(STUN_DATA_INDICATION);
+  msg.SetTransactionID("0000000000000000");
+
+  StunByteStringAttribute* magic_cookie_attr =
+      StunAttribute::CreateByteString(cricket::STUN_ATTR_MAGIC_COOKIE);
+  magic_cookie_attr->CopyBytes(binding_->magic_cookie().c_str(),
+                               binding_->magic_cookie().size());
+  msg.AddAttribute(magic_cookie_attr);
+
+  StunAddressAttribute* addr_attr =
+      StunAttribute::CreateAddress(STUN_ATTR_SOURCE_ADDRESS2);
+  addr_attr->SetFamily(1);
+  addr_attr->SetIP(from_addr.ip());
+  addr_attr->SetPort(from_addr.port());
+  msg.AddAttribute(addr_attr);
+
+  StunByteStringAttribute* data_attr =
+      StunAttribute::CreateByteString(STUN_ATTR_DATA);
+  assert(size <= 65536);
+  data_attr->CopyBytes(data, uint16(size));
+  msg.AddAttribute(data_attr);
+
+  SendStun(msg);
+}
+
+void RelayServerConnection::SendStun(const StunMessage& msg) {
+  // Note that the binding has been used again.
+  binding_->NoteUsed();
+
+  cricket::SendStun(msg, socket_, addr_pair_.source());
+}
+
+void RelayServerConnection::SendStunError(
+      const StunMessage& request, int error_code, const char* error_desc) {
+  // An error does not indicate use.  If no legitimate use off the binding
+  // occurs, we want it to be cleaned up even if errors are still occuring.
+
+  cricket::SendStunError(
+      request, socket_, addr_pair_.source(), error_code, error_desc,
+      binding_->magic_cookie());
+}
+
+void RelayServerConnection::Lock() {
+  locked_ = true;
+}
+
+void RelayServerConnection::Unlock() {
+  locked_ = false;
+}
+
+// IDs used for posted messages:
+const uint32 MSG_LIFETIME_TIMER = 1;
+
+RelayServerBinding::RelayServerBinding(
+    RelayServer* server, const std::string& username,
+    const std::string& password, uint32 lifetime)
+  : server_(server), username_(username), password_(password),
+    lifetime_(lifetime) {
+
+  // For now, every connection uses the standard magic cookie value.
+  magic_cookie_.append(
+      reinterpret_cast<const char*>(STUN_MAGIC_COOKIE_VALUE), 4);
+
+  // Initialize the last-used time to now.
+  NoteUsed();
+
+  // Set the first timeout check.
+  server_->thread()->PostDelayed(lifetime_, this, MSG_LIFETIME_TIMER);
+}
+
+RelayServerBinding::~RelayServerBinding() {
+  // Clear the outstanding timeout check.
+  server_->thread()->Clear(this);
+
+  // Clean up all of the connections.
+  for (size_t i = 0; i < internal_connections_.size(); ++i)
+    delete internal_connections_[i];
+  for (size_t i = 0; i < external_connections_.size(); ++i)
+    delete external_connections_[i];
+
+  // Remove this binding from the server's map.
+  server_->RemoveBinding(this);
+}
+
+void RelayServerBinding::AddInternalConnection(RelayServerConnection* conn) {
+  internal_connections_.push_back(conn);
+}
+
+void RelayServerBinding::AddExternalConnection(RelayServerConnection* conn) {
+  external_connections_.push_back(conn);
+}
+
+void RelayServerBinding::NoteUsed() {
+  last_used_ = GetMillisecondCount();
+}
+
+bool RelayServerBinding::HasMagicCookie(const char* bytes, size_t size) const {
+  if (size < 24 + magic_cookie_.size()) {
+    return false;
+  } else {
+    return 0 == std::memcmp(
+        bytes + 24, magic_cookie_.c_str(), magic_cookie_.size());
+  }
+}
+
+RelayServerConnection* RelayServerBinding::GetInternalConnection(
+    const SocketAddress& ext_addr) {
+
+  // Look for an internal connection that is locked to this address.
+  for (size_t i = 0; i < internal_connections_.size(); ++i) {
+    if (internal_connections_[i]->locked() &&
+        (ext_addr == internal_connections_[i]->default_destination()))
+      return internal_connections_[i];
+  }
+
+  // If one was not found, we send to the first connection.
+  assert(internal_connections_.size() > 0);
+  return internal_connections_[0];
+}
+
+RelayServerConnection* RelayServerBinding::GetExternalConnection(
+    const SocketAddress& ext_addr) {
+  for (size_t i = 0; i < external_connections_.size(); ++i) {
+    if (ext_addr == external_connections_[i]->addr_pair().source())
+      return external_connections_[i];
+  }
+  return 0;
+}
+
+void RelayServerBinding::OnMessage(Message *pmsg) {
+  if (pmsg->message_id == MSG_LIFETIME_TIMER) {
+    assert(!pmsg->pdata);
+
+    // If the lifetime timeout has been exceeded, then send a signal.
+    // Otherwise, just keep waiting.
+    if (GetMillisecondCount() >= last_used_ + lifetime_) {
+      SignalTimeout(this);
+    } else {
+      server_->thread()->PostDelayed(lifetime_, this, MSG_LIFETIME_TIMER);
+    }
+
+  } else {
+    assert(false);
+  }
+}
+
+} // namespace cricket