Fix memory leak

internal/turbotunnel/clientid.go

@@ -0,0 +1,37 @@
+// This package is a local fork of www.bamsoftware.com/git/dnstt.git/turbotunnel
+// (upstream v1.20241021.0). The only behavioural change from upstream is that
+// RemoteMap's background expiry goroutine is now stoppable via Close(), wired
+// through QueuePacketConn.Close(); see remotemap.go and queuepacketconn.go.
+// Upstream leaks that goroutine for the process lifetime, which is harmless for
+// the upstream one-shot server but leaks one goroutine per DNSTT restart in this
+// integration (hot-reload / auto-restart). clientid.go and consts.go are copied
+// verbatim.
+
+package turbotunnel
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+)
+
+// ClientID is an abstract identifier that binds together all the communications
+// belonging to a single client session, even though those communications may
+// arrive from multiple IP addresses or over multiple lower-level connections.
+// It plays the same role that an (IP address, port number) tuple plays in a
+// net.UDPConn: it's the return address pertaining to a long-lived abstract
+// client session. The client attaches its ClientID to each of its
+// communications, enabling the server to disambiguate requests among its many
+// clients. ClientID implements the net.Addr interface.
+type ClientID [8]byte
+
+func NewClientID() ClientID {
+	var id ClientID
+	_, err := rand.Read(id[:])
+	if err != nil {
+		panic(err)
+	}
+	return id
+}
+
+func (id ClientID) Network() string { return "clientid" }
+func (id ClientID) String() string  { return hex.EncodeToString(id[:]) }