XTLS Vision: Compatible with Go 1.27.3+ (#7176)

https://github.com/XTLS/Xray-core/pull/7176#issuecomment-6229087350

Fixes https://github.com/XTLS/Xray-core/issues/7162#issuecomment-6210430747

---------

Co-authored-by: RPRX <63339210+RPRX@users.noreply.github.com>

proxy/vless/vless.go

@@ -5,7 +5,28 @@
 // clients with 'socks' for proxying.
 package vless
 
+import (
+	"bytes"
+	"net"
+	"reflect"
+
+	"github.com/xtls/xray-core/common/utils"
+)
+
 const (
 	None = "none"
 	XRV  = "xtls-rprx-vision"
 )
+
+// Old TLS lib holds bytes.Buffer, but new TLS lib holds *bytes.Buffer
+// Since Xray has 3 TLS libraries (std, utls, REALITY server)
+// we detect the type of rawInput and return the appropriate pointer
+func AccessTLSBuffers(conn net.Conn) (*bytes.Reader, **bytes.Buffer) {
+	input := utils.AccessField[bytes.Reader](conn, "input")
+	field := reflect.ValueOf(conn).Elem().FieldByName("rawInput")
+	if field.Kind() == reflect.Pointer {
+		return input, utils.AccessField[*bytes.Buffer](conn, "rawInput")
+	}
+	raw := utils.AccessField[bytes.Buffer](conn, "rawInput")
+	return input, &raw
+}