fix: dns tcp hijack not working

listener/tun/ipstack/gvisor/handler.go

@@ -4,6 +4,7 @@ package gvisor
 
 import (
 	"encoding/binary"
+	"io"
 	"net"
 	"net/netip"
 	"time"
@@ -60,7 +61,7 @@ func (gh *gvHandler) HandleTCP(tunConn adapter.TCPConn) {
 					break
 				}
 
-				n, err := tunConn.Read(buf[:length])
+				n, err := io.ReadFull(tunConn, buf[:length])
 				if err != nil {
 					break
 				}
@@ -70,6 +71,11 @@ func (gh *gvHandler) HandleTCP(tunConn adapter.TCPConn) {
 					break
 				}
 
+				err = binary.Write(tunConn, binary.BigEndian, uint16(len(msg)))
+				if err != nil {
+					break
+				}
+
 				_, _ = tunConn.Write(msg)
 			}
 		}()

listener/tun/ipstack/system/stack.go

@@ -113,7 +113,7 @@ func New(device device.Device, dnsHijack []netip.AddrPort, tunAddress netip.Pref
 							break
 						}
 
-						n, err := conn.Read(buf[:length])
+						n, err := io.ReadFull(conn, buf[:length])
 						if err != nil {
 							break
 						}
@@ -123,6 +123,11 @@ func New(device device.Device, dnsHijack []netip.AddrPort, tunAddress netip.Pref
 							break
 						}
 
+						err = binary.Write(conn, binary.BigEndian, uint16(len(msg)))
+						if err != nil {
+							break
+						}
+
 						_, _ = conn.Write(msg)
 					}
 				}()