lib/nat: Add a nat package and service to track mappings on multiple IGDs

lib/nat/interface.go

@@ -0,0 +1,26 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package nat
+
+import (
+	"net"
+	"time"
+)
+
+type Protocol string
+
+const (
+	TCP Protocol = "TCP"
+	UDP          = "UDP"
+)
+
+type Device interface {
+	ID() string
+	GetLocalIPAddress() net.IP
+	AddPortMapping(protocol Protocol, internalPort, externalPort int, description string, duration time.Duration) (int, error)
+	GetExternalIPAddress() (net.IP, error)
+}