Handle fabric session protocol frames

2026-05-16 00:07:57 +03:00
parent c711bdc67c
commit 6ac41052e6
4 changed files with 311 additions and 1 deletions
@@ -0,0 +1,135 @@
+package fabricproto
+
+import "errors"
+
+var (
+	ErrUnsupportedSessionFrame = errors.New("unsupported fabric session frame")
+	ErrTrafficClassMismatch    = errors.New("fabric stream traffic class mismatch")
+)
+
+type SessionEventType string
+
+const (
+	SessionEventNone         SessionEventType = ""
+	SessionEventHello        SessionEventType = "hello"
+	SessionEventAuth         SessionEventType = "auth"
+	SessionEventReady        SessionEventType = "session_ready"
+	SessionEventStreamOpened SessionEventType = "stream_opened"
+	SessionEventData         SessionEventType = "data"
+	SessionEventAck          SessionEventType = "ack"
+	SessionEventCredit       SessionEventType = "credit"
+	SessionEventPing         SessionEventType = "ping"
+	SessionEventPong         SessionEventType = "pong"
+	SessionEventRouteUpdate  SessionEventType = "route_update"
+	SessionEventPressure     SessionEventType = "node_pressure"
+	SessionEventStreamClosed SessionEventType = "stream_closed"
+	SessionEventStreamReset  SessionEventType = "stream_reset"
+	SessionEventGoAway       SessionEventType = "goaway"
+)
+
+type SessionEvent struct {
+	Type         SessionEventType
+	StreamID     uint64
+	Sequence     uint64
+	TrafficClass TrafficClass
+	Payload      []byte
+}
+
+func (s *Session) HandleFrame(frame Frame) (SessionEvent, []Frame, error) {
+	if err := ValidateFrame(frame, DefaultMaxPayload); err != nil {
+		return SessionEvent{}, nil, err
+	}
+
+	switch frame.Type {
+	case FrameHello:
+		return sessionEvent(frame, SessionEventHello), nil, nil
+	case FrameAuth:
+		return sessionEvent(frame, SessionEventAuth), nil, nil
+	case FrameSessionReady:
+		return sessionEvent(frame, SessionEventReady), nil, nil
+	case FrameOpenStream:
+		if err := s.OpenStream(frame.StreamID, frame.TrafficClass); err != nil {
+			return SessionEvent{}, nil, err
+		}
+		return sessionEvent(frame, SessionEventStreamOpened), nil, nil
+	case FrameData:
+		event, err := s.handleDataFrame(frame)
+		if err != nil {
+			return SessionEvent{}, nil, err
+		}
+		return event, []Frame{{
+			Type:         FrameAck,
+			TrafficClass: frame.TrafficClass,
+			StreamID:     frame.StreamID,
+			Sequence:     frame.Sequence,
+		}}, nil
+	case FrameAck:
+		if err := s.Ack(frame.StreamID, frame.Sequence); err != nil {
+			return SessionEvent{}, nil, err
+		}
+		return sessionEvent(frame, SessionEventAck), nil, nil
+	case FramePing:
+		return sessionEvent(frame, SessionEventPing), []Frame{{
+			Type:     FramePong,
+			Sequence: frame.Sequence,
+			Payload:  append([]byte(nil), frame.Payload...),
+		}}, nil
+	case FramePong:
+		return sessionEvent(frame, SessionEventPong), nil, nil
+	case FrameRouteUpdate:
+		return sessionEvent(frame, SessionEventRouteUpdate), nil, nil
+	case FrameStreamCredit:
+		if err := s.AddCredit(frame.StreamID, int(frame.Sequence)); err != nil {
+			return SessionEvent{}, nil, err
+		}
+		return sessionEvent(frame, SessionEventCredit), nil, nil
+	case FrameNodePressure:
+		return sessionEvent(frame, SessionEventPressure), nil, nil
+	case FrameCloseStream:
+		if err := s.CloseStream(frame.StreamID); err != nil {
+			return SessionEvent{}, nil, err
+		}
+		return sessionEvent(frame, SessionEventStreamClosed), nil, nil
+	case FrameResetStream:
+		if err := s.ResetStream(frame.StreamID); err != nil {
+			return SessionEvent{}, nil, err
+		}
+		return sessionEvent(frame, SessionEventStreamReset), nil, nil
+	case FrameGoAway:
+		s.Close()
+		return sessionEvent(frame, SessionEventGoAway), nil, nil
+	default:
+		return SessionEvent{}, nil, ErrUnsupportedSessionFrame
+	}
+}
+
+func (s *Session) handleDataFrame(frame Frame) (SessionEvent, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.closed {
+		return SessionEvent{}, ErrSessionClosed
+	}
+	st, err := s.openStreamLocked(frame.StreamID)
+	if err != nil {
+		return SessionEvent{}, err
+	}
+	if frame.TrafficClass == 0 {
+		frame.TrafficClass = st.trafficClass
+	}
+	if frame.TrafficClass != st.trafficClass {
+		return SessionEvent{}, ErrTrafficClassMismatch
+	}
+	st.metrics.Received++
+	s.metrics.FramesReceived++
+	return sessionEvent(frame, SessionEventData), nil
+}
+
+func sessionEvent(frame Frame, eventType SessionEventType) SessionEvent {
+	return SessionEvent{
+		Type:         eventType,
+		StreamID:     frame.StreamID,
+		Sequence:     frame.Sequence,
+		TrafficClass: frame.TrafficClass,
+		Payload:      append([]byte(nil), frame.Payload...),
+	}
+}