Method create_stream

src/proxy/http2/Http2ConnectionState.cc:1755–1886

}

Http2Stream *
Http2ConnectionState::create_stream(Http2StreamId new_id, Http2Error &error)
{
  // first check if we've hit the active connection limit
  if (!session->get_netvc()->add_to_active_queue()) {
    error = Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_NO_ERROR,
                       "refused to create new stream, maxed out active connections");
    return nullptr;
  }

  // In half_close state, TS doesn't create new stream. Because GOAWAY frame is sent to client
  if (session->get_half_close_local_flag()) {
    error = Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_STREAM, Http2ErrorCode::HTTP2_ERROR_REFUSED_STREAM,
                       "refused to create new stream, because session is in half_close state");
    return nullptr;
  }

  bool is_client_streamid = http2_is_client_streamid(new_id);

  // 5.1.1 The identifier of a newly established stream MUST be numerically
  // greater than all streams that the initiating endpoint has opened or
  // reserved.  This governs streams that are opened using a HEADERS frame
  // and streams that are reserved using PUSH_PROMISE.  An endpoint that
  // receives an unexpected stream identifier MUST respond with a
  // connection error (Section 5.4.1) of type PROTOCOL_ERROR.
  if (is_client_streamid) {
    if (new_id <= latest_streamid_in) {
      error = Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_PROTOCOL_ERROR,
                         "recv headers new client id less than latest stream id");
      return nullptr;
    }
  } else {
    if (new_id <= latest_streamid_out) {
      error = Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_PROTOCOL_ERROR,
                         "recv headers new server id less than latest stream id");
      return nullptr;
    }
  }

  // Endpoints MUST NOT exceed the limit set by their peer.  An endpoint
  // that receives a HEADERS frame that causes their advertised concurrent
  // stream limit to be exceeded MUST treat this as a stream error.
  int check_max_concurrent_limit = 0;
  int check_count                = 0;
  if (is_client_streamid) {
    check_count = peer_streams_count_in;
    // If this is an outbound client stream, must check against the peer's max_concurrent
    if (session->is_outbound()) {
      check_max_concurrent_limit = peer_settings.get(HTTP2_SETTINGS_MAX_CONCURRENT_STREAMS);
    } else { // Inbound client streamm check against our own max_connecurent limits
      check_max_concurrent_limit = acknowledged_local_settings.get(HTTP2_SETTINGS_MAX_CONCURRENT_STREAMS);
    }
  } else { // Not a client stream (i.e. a push)
    check_count = peer_streams_count_out;
    // If this is an outbound non-client stream, must check against the local max_concurrent
    if (session->is_outbound()) {
      check_max_concurrent_limit = acknowledged_local_settings.get(HTTP2_SETTINGS_MAX_CONCURRENT_STREAMS);
    } else { // Inbound non-client streamm check against the peer's max_connecurent limits