refactor: Move vision implementation to a new package

transport/vless/vision/vision.go

@@ -0,0 +1,70 @@
+// Package vision implements VLESS flow `xtls-rprx-vision` introduced by Xray-core.
+package vision
+
+import (
+	"bytes"
+	gotls "crypto/tls"
+	"errors"
+	"fmt"
+	"net"
+	"reflect"
+	"unsafe"
+
+	N "github.com/Dreamacro/clash/common/net"
+	tlsC "github.com/Dreamacro/clash/component/tls"
+
+	"github.com/gofrs/uuid/v5"
+	"github.com/sagernet/sing/common"
+	utls "github.com/sagernet/utls"
+)
+
+var ErrNotTLS13 = errors.New("XTLS Vision based on TLS 1.3 outer connection")
+
+type connWithUpstream interface {
+	net.Conn
+	common.WithUpstream
+}
+
+func NewConn(conn connWithUpstream, userUUID *uuid.UUID) (*Conn, error) {
+	c := &Conn{
+		ExtendedReader:             N.NewExtendedReader(conn),
+		ExtendedWriter:             N.NewExtendedWriter(conn),
+		upstream:                   conn,
+		userUUID:                   userUUID,
+		packetsToFilter:            6,
+		needHandshake:              true,
+		readProcess:                true,
+		readFilterUUID:             true,
+		writeFilterApplicationData: true,
+	}
+	var t reflect.Type
+	var p unsafe.Pointer
+	switch underlying := conn.Upstream().(type) {
+	case *gotls.Conn:
+		//log.Debugln("type tls")
+		c.Conn = underlying.NetConn()
+		c.tlsConn = underlying
+		t = reflect.TypeOf(underlying).Elem()
+		p = unsafe.Pointer(underlying)
+	case *utls.UConn:
+		//log.Debugln("type *utls.UConn")
+		c.Conn = underlying.NetConn()
+		c.tlsConn = underlying
+		t = reflect.TypeOf(underlying.Conn).Elem()
+		p = unsafe.Pointer(underlying.Conn)
+	case *tlsC.UConn:
+		//log.Debugln("type *tlsC.UConn")
+		c.Conn = underlying.NetConn()
+		c.tlsConn = underlying.UConn
+		t = reflect.TypeOf(underlying.Conn).Elem()
+		//log.Debugln("t:%v", t)
+		p = unsafe.Pointer(underlying.Conn)
+	default:
+		return nil, fmt.Errorf(`failed to use vision, maybe "security" is not "tls" or "utls"`)
+	}
+	i, _ := t.FieldByName("input")
+	r, _ := t.FieldByName("rawInput")
+	c.input = (*bytes.Reader)(unsafe.Add(p, i.Offset))
+	c.rawInput = (*bytes.Buffer)(unsafe.Add(p, r.Offset))
+	return c, nil
+}