Add watchInterfaceEvents() listener

src/vpp/vpp_iface.go

@@ -0,0 +1,72 @@
+// Copyright 2025, IPng Networks GmbH, Pim van Pelt <pim@ipng.ch>
+
+package vpp
+
+import (
+	"os"
+
+	"go.fd.io/govpp/api"
+	interfaces "go.fd.io/govpp/binapi/interface"
+
+	"govpp-snmp-agentx/logger"
+)
+
+func WatchInterfaceEvents(ch api.Channel) error {
+	logger.Debugf("WatchInterfaceEvents() called - starting interface event monitoring")
+
+	notifChan := make(chan api.Message, 100)
+
+	// subscribe for specific event message
+	logger.Debugf("Subscribing to interface events...")
+	sub, err := ch.SubscribeNotification(notifChan, &interfaces.SwInterfaceEvent{})
+	if err != nil {
+		logger.Debugf("error subscribing to interface events: %v", err)
+		return err
+	}
+	logger.Debugf("Successfully subscribed to interface events")
+
+	// enable interface events in VPP
+	logger.Debugf("Enabling interface events in VPP...")
+	err = ch.SendRequest(&interfaces.WantInterfaceEvents{
+		PID:           uint32(os.Getpid()),
+		EnableDisable: 1,
+	}).ReceiveReply(&interfaces.WantInterfaceEventsReply{})
+	if err != nil {
+		logger.Debugf("error enabling interface events: %v", err)
+		return err
+	}
+
+	logger.Debugf("Interface events enabled in VPP, starting event listener goroutine")
+
+	// receive notifications
+	go func() {
+		logger.Debugf("Interface event listener goroutine started")
+		defer func() {
+			logger.Debugf("Interface event listener goroutine shutting down")
+			// disable interface events in VPP
+			err = ch.SendRequest(&interfaces.WantInterfaceEvents{
+				PID:           uint32(os.Getpid()),
+				EnableDisable: 0,
+			}).ReceiveReply(&interfaces.WantInterfaceEventsReply{})
+			if err != nil {
+				logger.Debugf("error disabling interface events: %v", err)
+			}
+
+			// unsubscribe from receiving events
+			err = sub.Unsubscribe()
+			if err != nil {
+				logger.Debugf("error unsubscribing from interface events: %v", err)
+			}
+		}()
+
+		logger.Debugf("Interface event listener waiting for events...")
+		for notif := range notifChan {
+			e := notif.(*interfaces.SwInterfaceEvent)
+			logger.Debugf("interface event: SwIfIndex=%d, Flags=%d, Deleted=%t",
+				e.SwIfIndex, e.Flags, e.Deleted)
+		}
+		logger.Debugf("Interface event listener goroutine ended")
+	}()
+
+	return nil
+}