From b76d0e210937c276e4a62a499807cbf43fc29298 Mon Sep 17 00:00:00 2001
From: gVisor bot <gvisor-bot@google.com>
Date: Sun, 13 Mar 2022 18:34:49 +0800
Subject: [PATCH] [Fixed] handle network protocol[0] panic (not pretty)

---
 listener/tun/ipstack/gvisor/tundns.go | 15 ++++++++++++---
 listener/tun/ipstack/gvisor/utils.go  | 14 ++++++++++++--
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/listener/tun/ipstack/gvisor/tundns.go b/listener/tun/ipstack/gvisor/tundns.go
index 7fba6bbe..51368675 100644
--- a/listener/tun/ipstack/gvisor/tundns.go
+++ b/listener/tun/ipstack/gvisor/tundns.go
@@ -85,7 +85,8 @@ func (e *dnsEndpoint) HandlePacket(id stack.TransportEndpointID, pkt *stack.Pack
 	var msg D.Msg
 	msg.Unpack(pkt.Data().AsRange().ToOwnedView())
 	writer := dnsResponseWriter{s: e.stack, pkt: pkt, id: id}
-	log.Debugln("[DNS] hijack udp:%s:%d", id.LocalAddress.String(), id.LocalPort)
+	log.Debugln("[DNS] hijack udp:%s:%d from %s:%d", id.LocalAddress.String(), id.LocalPort,
+		id.RemoteAddress.String(), id.RemotePort)
 	go e.server.ServeDNS(&writer, &msg)
 }
 
@@ -139,9 +140,17 @@ func (w *dnsResponseWriter) Write(b []byte) (int, error) {
 	v := buffer.NewView(len(b))
 	copy(v, b)
 	data := v.ToVectorisedView()
+
 	// w.id.LocalAddress is the source ip of DNS response
-	r, _ := w.s.FindRoute(w.pkt.NICID, w.id.LocalAddress, w.id.RemoteAddress, w.pkt.NetworkProtocolNumber, false /* multicastLoop */)
-	return writeUDP(r, data, w.id.LocalPort, w.id.RemotePort)
+	if !w.pkt.NetworkHeader().View().IsEmpty() &&
+		(w.pkt.NetworkProtocolNumber == ipv4.ProtocolNumber ||
+			w.pkt.NetworkProtocolNumber == ipv6.ProtocolNumber) {
+		r, _ := w.s.FindRoute(w.pkt.NICID, w.id.LocalAddress, w.id.RemoteAddress, w.pkt.NetworkProtocolNumber, false /* multicastLoop */)
+		return writeUDP(r, data, w.id.LocalPort, w.id.RemotePort)
+	} else {
+		log.Debugln("the network protocl[%d] is not available", w.pkt.NetworkProtocolNumber)
+		return 0, fmt.Errorf("the network protocl[%d] is not available", w.pkt.NetworkProtocolNumber)
+	}
 }
 
 func (w *dnsResponseWriter) Close() error {
diff --git a/listener/tun/ipstack/gvisor/utils.go b/listener/tun/ipstack/gvisor/utils.go
index 44063f0b..7b1b2588 100644
--- a/listener/tun/ipstack/gvisor/utils.go
+++ b/listener/tun/ipstack/gvisor/utils.go
@@ -2,6 +2,9 @@ package gvisor
 
 import (
 	"fmt"
+	"github.com/Dreamacro/clash/log"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
 	"net"
 
 	"github.com/Dreamacro/clash/component/resolver"
@@ -40,8 +43,15 @@ func (c *fakeConn) WriteBack(b []byte, addr net.Addr) (n int, err error) {
 		localPort = uint16(udpaddr.Port)
 	}
 
-	r, _ := c.s.FindRoute(c.pkt.NICID, localAddress, c.id.RemoteAddress, c.pkt.NetworkProtocolNumber, false /* multicastLoop */)
-	return writeUDP(r, data, localPort, c.id.RemotePort)
+	if !c.pkt.NetworkHeader().View().IsEmpty() &&
+		(c.pkt.NetworkProtocolNumber == ipv4.ProtocolNumber ||
+			c.pkt.NetworkProtocolNumber == ipv6.ProtocolNumber) {
+		r, _ := c.s.FindRoute(c.pkt.NICID, localAddress, c.id.RemoteAddress, c.pkt.NetworkProtocolNumber, false /* multicastLoop */)
+		return writeUDP(r, data, localPort, c.id.RemotePort)
+	} else {
+		log.Debugln("the network protocl[%d] is not available", c.pkt.NetworkProtocolNumber)
+		return 0, fmt.Errorf("the network protocl[%d] is not available", c.pkt.NetworkProtocolNumber)
+	}
 }
 
 func (c *fakeConn) LocalAddr() net.Addr {