add go-tun2socks code

core/handler.go

@@ -0,0 +1,31 @@
+package core
+
+import (
+	"net"
+)
+
+// TCPConnHandler handles TCP connections comming from TUN.
+type TCPConnHandler interface {
+	// Handle handles the conn for target.
+	Handle(conn net.Conn, target *net.TCPAddr) error
+}
+
+// UDPConnHandler handles UDP connections comming from TUN.
+type UDPConnHandler interface {
+	// Connect connects the proxy server. Note that target can be nil.
+	Connect(conn UDPConn, target *net.UDPAddr) error
+
+	// ReceiveTo will be called when data arrives from TUN.
+	ReceiveTo(conn UDPConn, data []byte, addr *net.UDPAddr) error
+}
+
+var tcpConnHandler TCPConnHandler
+var udpConnHandler UDPConnHandler
+
+func RegisterTCPConnHandler(h TCPConnHandler) {
+	tcpConnHandler = h
+}
+
+func RegisterUDPConnHandler(h UDPConnHandler) {
+	udpConnHandler = h
+}