feat: VLESS support packet encodings (#334)

* adjust: Do not use XTLS on H2 connections

* feat: VLESS support XUDP fullcone NAT

* fix: VLESS with PacketAddr does not work

* fix: VLESS XUDP crash

transport/gun/gun_xtls.go

@@ -1,60 +0,0 @@
-// Modified from: https://github.com/Qv2ray/gun-lite
-// License: MIT
-
-package gun
-
-import (
-	"crypto/tls"
-	"fmt"
-	"net"
-
-	xtls "github.com/xtls/go"
-	"golang.org/x/net/http2"
-)
-
-func NewHTTP2XTLSClient(dialFn DialFn, tlsConfig *tls.Config) *TransportWrap {
-	wrap := TransportWrap{}
-	dialFunc := func(network, addr string, cfg *tls.Config) (net.Conn, error) {
-		pconn, err := dialFn(network, addr)
-		if err != nil {
-			return nil, err
-		}
-
-		wrap.remoteAddr = pconn.RemoteAddr()
-		xtlsConfig := &xtls.Config{
-			InsecureSkipVerify: cfg.InsecureSkipVerify,
-			ServerName:         cfg.ServerName,
-		}
-
-		cn := xtls.Client(pconn, xtlsConfig)
-		if err := cn.Handshake(); err != nil {
-			pconn.Close()
-			return nil, err
-		}
-		state := cn.ConnectionState()
-		if p := state.NegotiatedProtocol; p != http2.NextProtoTLS {
-			cn.Close()
-			return nil, fmt.Errorf("http2: unexpected ALPN protocol %s, want %s", p, http2.NextProtoTLS)
-		}
-		return cn, nil
-	}
-
-	wrap.Transport = &http2.Transport{
-		DialTLS:            dialFunc,
-		TLSClientConfig:    tlsConfig,
-		AllowHTTP:          false,
-		DisableCompression: true,
-		PingTimeout:        0,
-	}
-
-	return &wrap
-}
-
-func StreamGunWithXTLSConn(conn net.Conn, tlsConfig *tls.Config, cfg *Config) (net.Conn, error) {
-	dialFn := func(network, addr string) (net.Conn, error) {
-		return conn, nil
-	}
-
-	transport := NewHTTP2XTLSClient(dialFn, tlsConfig)
-	return StreamGunWithTransport(transport, cfg)
-}