TUN-7480: Added a timeout for unregisterUDP.

I deliberately kept this as an unregistertimeout because that was the
intent. In the future we could change this to a UDPConnConfig if we want
to pass multiple values here.

The idea of this PR is simply to add a configurable unregister UDP
timeout.

cmd/cloudflared/tunnel/cmd.go

@@ -79,6 +79,9 @@ const (
 	// hostKeyPath is the path of the dir to save SSH host keys too
 	hostKeyPath = "host-key-path"
 
+	// udpUnregisterSessionTimeout is how long we wait before we stop trying to unregister a UDP session from the edge
+	udpUnregisterSessionTimeoutFlag = "udp-unregister-session-timeout"
+
 	// uiFlag is to enable launching cloudflared in interactive UI mode
 	uiFlag = "ui"
 
@@ -683,6 +686,11 @@ func tunnelFlags(shouldHide bool) []cli.Flag {
 			Value:  4,
 			Hidden: true,
 		}),
+		altsrc.NewDurationFlag(&cli.DurationFlag{
+			Name:   udpUnregisterSessionTimeoutFlag,
+			Value:  5 * time.Second,
+			Hidden: true,
+		}),
 		altsrc.NewStringFlag(&cli.StringFlag{
 			Name:  connectorLabelFlag,
 			Usage: "Use this option to give a meaningful label to a specific connector. When a tunnel starts up, a connector id unique to the tunnel is generated. This is a uuid. To make it easier to identify a connector, we will use the hostname of the machine the tunnel is running on along with the connector ID. This option exists if one wants to have more control over what their individual connectors are called.",

cmd/cloudflared/tunnel/configuration.go

@@ -231,14 +231,15 @@ func prepareTunnelConfig(
 		Observer:        observer,
 		ReportedVersion: info.Version(),
 		// Note TUN-3758 , we use Int because UInt is not supported with altsrc
-		Retries:            uint(c.Int("retries")),
-		RunFromTerminal:    isRunningFromTerminal(),
-		NamedTunnel:        namedTunnel,
-		ProtocolSelector:   protocolSelector,
-		EdgeTLSConfigs:     edgeTLSConfigs,
-		NeedPQ:             needPQ,
-		PQKexIdx:           pqKexIdx,
-		MaxEdgeAddrRetries: uint8(c.Int("max-edge-addr-retries")),
+		Retries:                     uint(c.Int("retries")),
+		RunFromTerminal:             isRunningFromTerminal(),
+		NamedTunnel:                 namedTunnel,
+		ProtocolSelector:            protocolSelector,
+		EdgeTLSConfigs:              edgeTLSConfigs,
+		NeedPQ:                      needPQ,
+		PQKexIdx:                    pqKexIdx,
+		MaxEdgeAddrRetries:          uint8(c.Int("max-edge-addr-retries")),
+		UDPUnregisterSessionTimeout: c.Duration(udpUnregisterSessionTimeoutFlag),
 	}
 	packetConfig, err := newPacketConfig(c, log)
 	if err != nil {