FIrs

2026-05-15 17:42:14 +02:00
commit e3389f932b
40 changed files with 7622 additions and 0 deletions
@@ -0,0 +1,161 @@
+package main
+
+import (
+	"log"
+	"net"
+	"time"
+)
+
+const (
+	silenceTimeout = 5 * time.Second
+	reconnectDelay = 2 * time.Second
+	readBufSize    = 65536
+)
+
+// UDPClient manages the UDP connection to the MARTe2 streamer.
+type UDPClient struct {
+	serverAddr string
+	localPort  int
+	hub        *Hub
+
+	stopCh chan struct{}
+}
+
+// NewUDPClient creates a UDPClient. Call Run() in a goroutine.
+func NewUDPClient(serverAddr string, localPort int, hub *Hub) *UDPClient {
+	return &UDPClient{
+		serverAddr: serverAddr,
+		localPort:  localPort,
+		hub:        hub,
+		stopCh:     make(chan struct{}),
+	}
+}
+
+// Stop asks the client to disconnect and exit.
+func (u *UDPClient) Stop() {
+	close(u.stopCh)
+}
+
+// Run is the main loop; it reconnects automatically if the server goes silent.
+func (u *UDPClient) Run() {
+	for {
+		select {
+		case <-u.stopCh:
+			return
+		default:
+		}
+
+		log.Printf("udp: connecting to %s (local port %d)", u.serverAddr, u.localPort)
+		err := u.runSession()
+		if err != nil {
+			log.Printf("udp: session ended: %v", err)
+		}
+
+		// Check stop before sleeping.
+		select {
+		case <-u.stopCh:
+			return
+		case <-time.After(reconnectDelay):
+		}
+	}
+}
+
+// runSession opens a UDP socket, sends CONNECT, reads data until the server
+// goes silent or an error occurs.
+func (u *UDPClient) runSession() error {
+	localAddr := &net.UDPAddr{Port: u.localPort}
+	conn, err := net.ListenUDP("udp4", localAddr)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	serverAddr, err := net.ResolveUDPAddr("udp4", u.serverAddr)
+	if err != nil {
+		return err
+	}
+
+	// Send CONNECT.
+	if _, err := conn.WriteToUDP(BuildConnectPacket(), serverAddr); err != nil {
+		return err
+	}
+	log.Printf("udp: sent CONNECT")
+
+	reassembler := NewReassembler(2 * time.Second)
+	buf := make([]byte, readBufSize)
+	var currentSigs []SignalInfo
+
+	for {
+		// Silence timeout.
+		conn.SetReadDeadline(time.Now().Add(silenceTimeout))
+
+		n, _, err := conn.ReadFromUDP(buf)
+		arrivalTime := time.Now()
+		if err != nil {
+			// Send DISCONNECT best-effort before returning.
+			conn.WriteToUDP(BuildDisconnectPacket(), serverAddr)
+			return err
+		}
+
+		if n < HeaderSize {
+			log.Printf("udp: short datagram (%d bytes), skipping", n)
+			continue
+		}
+
+		hdr, err := ParseHeader(buf[:n])
+		if err != nil {
+			log.Printf("udp: parse header: %v", err)
+			continue
+		}
+
+		payload := make([]byte, n-HeaderSize)
+		copy(payload, buf[HeaderSize:n])
+
+		complete, ok := reassembler.AddFragment(hdr, payload)
+		if !ok {
+			continue
+		}
+
+		switch hdr.Type {
+		case PktConfig:
+			sigs, err := ParseConfig(complete)
+			if err != nil {
+				log.Printf("udp: parse config: %v", err)
+				continue
+			}
+			currentSigs = sigs
+			log.Printf("udp: received CONFIG (%d signals)", len(sigs))
+			u.hub.UpdateConfig(sigs)
+
+		case PktData:
+			if len(currentSigs) == 0 {
+				// We haven't received a CONFIG yet – ignore.
+				continue
+			}
+			sample, err := ParseData(complete, currentSigs, arrivalTime)
+			if err != nil {
+				log.Printf("udp: parse data: %v", err)
+				continue
+			}
+			u.hub.PushData(sample)
+
+		case PktACK:
+			log.Printf("udp: received ACK (counter=%d)", hdr.Counter)
+
+		case PktDisconnect:
+			log.Printf("udp: server sent DISCONNECT")
+			return nil
+
+		default:
+			log.Printf("udp: unknown packet type %d", hdr.Type)
+		}
+
+		// Check stop request.
+		select {
+		case <-u.stopCh:
+			conn.WriteToUDP(BuildDisconnectPacket(), serverAddr)
+			return nil
+		default:
+		}
+	}
+}