relayserver.cxx

由GOOGLE的JINGLE项目中移植的网络库

  // 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);

  size_t i;
  // Clean up all of the connections.
  for (i = 0; i < internal_connections_.size(); ++i)
    delete internal_connections_[i];
  for (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 == 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