ipn/wg: m add close observer state

Author: ignoramous

intra/ipn/wg/wgconn.go

@@ -108,6 +108,7 @@ const (
 	Csn PktDir = "nots" // not transport data (send)
 	Con PktDir = "conn" // e.g. dial, announce, accept
 	Opn PktDir = "open" // open conn to the wg endpoint
+	Clo PktDir = "clos" // close conn to the wg endpoint
 	Drp PktDir = "drop" // ignored packet
 )
 
@@ -399,6 +400,8 @@ func (s *StdNetBind) Close() error {
 		s.blackhole4 = false
 		s.blackhole6 = false
 
+		s.observer(Clo, nil)
+
 		log.I("wg: bind: %s close; addrs %s + %s; err4? %v err6? %v", s.id, addr1, addr2, err1, err2)
 		return core.JoinErr(err1, err2)
 	}

intra/ipn/wgproxy.go

@@ -1589,6 +1589,7 @@ func (h *wgtun) serve(network, local string) (pc net.PacketConn, err error) {
 
 func (h *wgtun) listener(op wg.PktDir, err error) {
 	s := h.status.Load()
+	cur := s
 	if op.Read() {
 		h.latestRxErr.Store(err)
 	} else if op.Write() {
@@ -1610,16 +1611,20 @@ func (h *wgtun) listener(op wg.PktDir, err error) {
 
 	defer func() {
 		h.statusReason.Store(why)
-		cur := h.status.Load()
-		stoppedOrPaused := cur == END || cur == TPU
 		updated := false
-		if !stoppedOrPaused {
+		if cur != s {
 			updated = h.status.Cas(cur, s)
 		}
-		logeif(!updated)("wg: %s listener: %s; status %s => %s; end/pause? %t, statusupdated? %t, why: %s",
-			h.tag(), op, pxstatus(cur), pxstatus(s), stoppedOrPaused, !updated, why)
+		logeif(!updated)("wg: %s listener: %s; status %s => %s; transition? %t, statusupdated? %t, why: %s",
+			h.tag(), op, pxstatus(cur), pxstatus(s), cur != s, !updated, why)
 	}()
 
+	if op == wg.Clo {
+		why = "TNT: closed; prev: " + pxstatus(s).String()
+		s = TNT
+		return
+	}
+
 	now := now()
 	age := now - h.since
 	if err != nil { // failing