Fix handling 4-in-6 IP for WriteBack

comzyh · Jul 1, 2023 · 2e2f6f0 · 2e2f6f0
1 parent 06eaed0
commit 2e2f6f0
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Showing 2 changed files with 5 additions and 0 deletions.
diff --git a/listener/listener.go b/listener/listener.go
@@ -355,6 +355,7 @@ func ReCreateTun(conf config.Tun, tcpIn chan<- C.ConnContext, udpIn chan<- *inbo
 	}
 	tunAdapter.ReCreateDNSServer(conf.DNSListen)
 }
+
 func ResetDNSResolver(resolver *dns.Resolver, mapper *dns.ResolverEnhancer) {
 	if tunAdapter != nil {
 		tunAdapter.ResetDNSResolver(resolver, mapper)

diff --git a/listener/tun/utils.go b/listener/tun/utils.go
@@ -37,6 +37,10 @@ func (c *fakeConn) WriteBack(b []byte, addr net.Addr) (n int, err error) {
 	} else {
 		udpaddr, _ := addr.(*net.UDPAddr)
 		localAddress = tcpip.AddrFromSlice(udpaddr.IP)
+		// We may get 4-in-6 IP here, but should not use 16 bytes IP in FindRoute
+		if c.pkt.NetworkProtocolNumber == header.IPv4ProtocolNumber {
+			localAddress = localAddress.To4()
+		}
 		localPort = uint16(udpaddr.Port)
 	}