TUN-8158: Add logging to confirm when ICMP reply is returned to the edge

ingress/icmp_posix.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
+	"sync/atomic"
 
 	"github.com/google/gopacket/layers"
 	"github.com/rs/zerolog"
@@ -46,6 +47,7 @@ type flow3Tuple struct {
 type icmpEchoFlow struct {
 	*packet.ActivityTracker
 	closeCallback  func() error
+	closed         *atomic.Bool
 	src            netip.Addr
 	originConn     *icmp.PacketConn
 	responder      *packetResponder
@@ -59,6 +61,7 @@ func newICMPEchoFlow(src netip.Addr, closeCallback func() error, originConn *icm
 	return &icmpEchoFlow{
 		ActivityTracker: packet.NewActivityTracker(),
 		closeCallback:   closeCallback,
+		closed:          &atomic.Bool{},
 		src:             src,
 		originConn:      originConn,
 		responder:       responder,
@@ -86,9 +89,14 @@ func (ief *icmpEchoFlow) Equal(other packet.Funnel) bool {
 }
 
 func (ief *icmpEchoFlow) Close() error {
+	ief.closed.Store(true)
 	return ief.closeCallback()
 }
 
+func (ief *icmpEchoFlow) IsClosed() bool {
+	return ief.closed.Load()
+}
+
 // sendToDst rewrites the echo ID to the one assigned to this flow
 func (ief *icmpEchoFlow) sendToDst(dst netip.Addr, msg *icmp.Message) error {
 	ief.UpdateLastActive()