Fixed error handling IPv6

proxy/main.go

@@ -72,43 +72,57 @@ func pipeForward(reader io.Reader, writer io.Writer, prefix string, passthrough
 
 		// Handle Ethernet frame
 		frame := packet.Layer(layers.LayerTypeEthernet).(*layers.Ethernet)
-		if !passthrough && prefix == cmd.In {
+		if prefix == cmd.In {
 			log.Debug(prefix, "Incoming MAC rewritten ", frame.DstMAC, OldMac)
 			frame.DstMAC = OldMac
-		} else if !passthrough && prefix == cmd.Out {
+		} else if prefix == cmd.Out {
 			log.Debug(prefix, "Outgoing MAC rewritten ", frame.SrcMAC, NewMac)
 			frame.SrcMAC = NewMac
 		}
 
-		// Handle IP packet
+		// Handle IPv6 packet
 		if ipv4layer := packet.Layer(layers.LayerTypeIPv4); ipv4layer != nil {
 			ipv4Packet, _ := ipv4layer.(*layers.IPv4)
-			if !passthrough && prefix == cmd.In {
+			if prefix == cmd.In {
 				log.Debug(prefix, "Incoming IP rewritten ", ipv4Packet.DstIP, OldIP)
 				ipv4Packet.DstIP = OldIP
-			} else if !passthrough && prefix == cmd.Out {
-				log.Debug(prefix, "Outgoing IP rewritten ", ipv4Packet.SrcIP, NewMac)
+			} else if prefix == cmd.Out {
+				log.Debug(prefix, "Outgoing IP rewritten ", ipv4Packet.SrcIP, NewIP)
 				ipv4Packet.SrcIP = NewIP
 			}
 
 			// Handle ICMP packet (based on IPv4)
 			if icmpLayer := packet.Layer(layers.LayerTypeICMPv4); icmpLayer != nil {
 				icmpPacket, _ := icmpLayer.(*layers.ICMPv4)
-				log.Infof("%s ICMP packet\nType/Code:\t%s\n", prefix, icmpPacket.TypeCode.String())
+				log.Debugf("%s ICMP packet\nType/Code:\t%s\n", prefix, icmpPacket.TypeCode.String())
 			}
 
-			// Handle DHCP packet (based on IPv4)
+			// Handle DHCP packet (based on IPv4) - drop for now
 			if dhcpLayer := packet.Layer(layers.LayerTypeDHCPv4); dhcpLayer != nil && !passthrough {
 				//dhcpPacket, _ := dhcpLayer.(*layers.DHCPv4)
 				log.Info(prefix, "DHCP packet dropped")
 				continue
 			}
+
+			// Handle TCP packet
+			if tcpLayer := packet.Layer(layers.LayerTypeTCP); tcpLayer != nil {
+				tcpPacket, _ := tcpLayer.(*layers.TCP)
+				if err := tcpPacket.SetNetworkLayerForChecksum(ipv4Packet); err != nil {
+					log.Error(prefix, "Error setting network layer for checksum", err)
+				}
+			}
+		}
+
+		// Drop IPv6 packets
+		if ipv6layer := packet.Layer(layers.LayerTypeIPv6); ipv6layer != nil && !passthrough {
+			log.Info(prefix, "IPv6 packet dropped")
+			continue
 		}
 
 		// Handle ARP packet
 		if frame.EthernetType == layers.EthernetTypeARP {
 			arpPacket := packet.Layer(layers.LayerTypeARP).(*layers.ARP)
-			log.Infof(
+			log.Debugf(
 				"%sARP before modification\nAddrType:\t%s\nProtocol:\t%s\nOperation:\t%s\n"+
 					"SrcHwAddress:\t%s\nSrcProtAddress:\t%s\nDstHwAddress:\t%s\nDstProtAddress:\t%s\n",
 				prefix,
@@ -121,27 +135,26 @@ func pipeForward(reader io.Reader, writer io.Writer, prefix string, passthrough
 				net.IP(arpPacket.DstProtAddress),
 			)
 
-			if !passthrough && prefix == cmd.In {
-				log.Debug(prefix, "Incoming MAC rewritten (ARP) ", net.HardwareAddr(arpPacket.DstHwAddress), OldMac)
+			if prefix == cmd.In {
+				arpPacket.DstProtAddress = OldIP
+				log.Debugf(
+					"%sARP after modification\nDstProtAddress:\t%s\n",
+					prefix,
+					net.IP(arpPacket.DstProtAddress),
+				)
 				if arpPacket.Operation == layers.ARPReply {
+					isInteresting = true
 					arpPacket.DstHwAddress = OldMac
-					arpPacket.DstProtAddress = OldIP
-					log.Infof(
-						"%sARP after modification\nDstProtAddress:\t%s\n",
-						prefix,
-						net.IP(arpPacket.DstProtAddress),
-					)
-					log.Infof(
+					log.Debugf(
 						"%sDstHwAddress:\t%s\n",
 						prefix,
 						net.HardwareAddr(arpPacket.DstHwAddress),
 					)
 				}
-			} else if !passthrough && prefix == cmd.Out {
-				log.Debug(prefix, "Outgoing MAC rewritten (ARP) ", net.HardwareAddr(arpPacket.SourceHwAddress), NewMac)
+			} else if prefix == cmd.Out {
 				arpPacket.SourceHwAddress = NewMac
 				arpPacket.SourceProtAddress = NewIP
-				log.Infof(
+				log.Debugf(
 					"%sARP after modification\nSrcHwAddress:\t%s\nSrcProtAddress:\t%s\n",
 					prefix,
 					net.HardwareAddr(arpPacket.SourceHwAddress),
@@ -150,6 +163,13 @@ func pipeForward(reader io.Reader, writer io.Writer, prefix string, passthrough
 			}
 		}
 
+		// Forward original frame to other plug
+		if passthrough {
+			writer.Write(frameLength)
+			writer.Write(frameBytes)
+			continue
+		}
+
 		// Serialize packet back to binary
 		buf := gopacket.NewSerializeBuffer()
 		opts := gopacket.SerializeOptions{ComputeChecksums: true, FixLengths: true}
@@ -162,13 +182,13 @@ func pipeForward(reader io.Reader, writer io.Writer, prefix string, passthrough
 		binary.BigEndian.PutUint16(newFrameLength, uint16(len(newFrameBytes)))
 
 		// Write interesting things to debug file
-		if isInteresting && !passthrough {
-			util.WriteBinary(fmt.Sprintf("/tmp/arp_%di.dat", time.Now().Unix()), frameBytes)
-			util.WriteBinary(fmt.Sprintf("/tmp/arp_%do.dat", time.Now().Unix()), newFrameBytes)
+		if isInteresting {
+			util.WriteBinary(fmt.Sprintf("/tmp/pck_%di.dat", time.Now().Unix()), frameBytes)
+			util.WriteBinary(fmt.Sprintf("/tmp/pck_%do.dat", time.Now().Unix()), newFrameBytes)
 			//util.WritePcap("xyz.pcap", packet.Data(), packet.Metadata().CaptureInfo)
 		}
 
-		// Forward original frame to other plug
+		// Forward modified frame to other plug
 		writer.Write(newFrameLength)
 		writer.Write(newFrameBytes)
 	}