Add tun inbound for linux

constant/cgo.go

@@ -1,3 +1,5 @@
+//go:build cgo
+
 package constant
 
 const CGO_ENABLED = true

constant/proxy.go

@@ -7,4 +7,5 @@ const (
 	TypeHTTP        = "http"
 	TypeMixed       = "mixed"
 	TypeShadowsocks = "shadowsocks"
+	TypeTun         = "tun"
 )