net/portmapper: put mappings and releases into an execqueuecmol/run_portmapper_in_exec_queue

We had an issue where releasing mappings would cause a deadlock when the
UPnP gateway did not respond. Instead of working on mappings sync, put
it into an exec queue and add a timeout on releasing the mappings.

Updates tailscale/corp#33888
Updates tailscale/corp#33619

Signed-off-by: Claus Lensbøl <claus@tailscale.com>

2 files changed, 14 insertions, 9 deletions

diff --git a/feature/debugportmapper/debugportmapper.go b/feature/debugportmapper/debugportmapper.go
index 2625086c6..0a1038436 100644
--- a/feature/debugportmapper/debugportmapper.go
+++ b/feature/debugportmapper/debugportmapper.go
@@ -109,10 +109,11 @@ func serveDebugPortmap(h *localapi.Handler, w http.ResponseWriter, r *http.Reque
 
 	var c *portmapper.Client
 	c = portmapper.NewClient(portmapper.Config{
-		Logf:       logger.WithPrefix(logf, "portmapper: "),
-		NetMon:     h.LocalBackend().NetMon(),
-		DebugKnobs: debugKnobs,
-		EventBus:   h.LocalBackend().EventBus(),
+		ShutdownCtx: ctx,
+		Logf:        logger.WithPrefix(logf, "portmapper: "),
+		NetMon:      h.LocalBackend().NetMon(),
+		DebugKnobs:  debugKnobs,
+		EventBus:    h.LocalBackend().EventBus(),
 		OnChange: func() {
 			logf("portmapping changed.")
 			logf("have mapping: %v", c.HaveMapping())
diff --git a/feature/portmapper/portmapper.go b/feature/portmapper/portmapper.go
index d1b903cb6..9c9d6acfc 100644
--- a/feature/portmapper/portmapper.go
+++ b/feature/portmapper/portmapper.go
@@ -6,6 +6,8 @@
 package portmapper
 
 import (
+	"context"
+
 	"tailscale.com/feature"
 	"tailscale.com/net/netmon"
 	"tailscale.com/net/portmapper"
@@ -20,16 +22,18 @@ func init() {
 }
 
 func newPortMapper(
+	ctx context.Context,
 	logf logger.Logf,
 	bus *eventbus.Bus,
 	netMon *netmon.Monitor,
 	disableUPnPOrNil func() bool,
-	onlyTCP443OrNil func() bool) portmappertype.Client {
-
+	onlyTCP443OrNil func() bool,
+) portmappertype.Client {
 	pm := portmapper.NewClient(portmapper.Config{
-		EventBus: bus,
-		Logf:     logf,
-		NetMon:   netMon,
+		ShutdownCtx: ctx,
+		EventBus:    bus,
+		Logf:        logf,
+		NetMon:      netMon,
 		DebugKnobs: &portmapper.DebugKnobs{
 			DisableAll:      onlyTCP443OrNil,
 			DisableUPnPFunc: disableUPnPOrNil,