Beispiel #1
0
// Given an EvePacket, convert the payload to a PCAP faking out the
// headers as best we can.
//
// A buffer containing the 1 packet pcap file will be returned.
func EvePayloadToPcap(event *EveEvent) ([]byte, error) {
	buffer := gopacket.NewSerializeBuffer()
	options := gopacket.SerializeOptions{
		FixLengths:       true,
		ComputeChecksums: true,
	}

	payloadLayer := gopacket.Payload(event.Payload.Bytes())
	payloadLayer.SerializeTo(buffer, options)

	srcIp := net.ParseIP(event.SrcIP)
	if srcIp == nil {
		return nil, fmt.Errorf("Failed to parse IP address %s.", event.SrcIP)
	}
	dstIp := net.ParseIP(event.DstIP)
	if dstIp == nil {
		return nil, fmt.Errorf("Failed to parse IP address %s.", event.DstIP)
	}

	proto, err := ProtoNumber(event.Proto)
	if err != nil {
		return nil, err
	}

	switch proto {
	case layers.IPProtocolTCP:
		// Could probably fake up a better TCP layer here.
		tcpLayer := layers.TCP{
			SrcPort: layers.TCPPort(event.SrcPort),
			DstPort: layers.TCPPort(event.DstPort),
		}
		tcpLayer.SerializeTo(buffer, options)
		break
	case layers.IPProtocolUDP:
		udpLayer := layers.UDP{
			SrcPort: layers.UDPPort(event.SrcPort),
			DstPort: layers.UDPPort(event.DstPort),
		}
		udpLayer.SerializeTo(buffer, options)
		break
	case layers.IPProtocolICMPv4:
		icmpLayer := layers.ICMPv4{
			TypeCode: layers.CreateICMPv4TypeCode(
				event.IcmpType, event.IcmpCode),
			Id:  0,
			Seq: 0,
		}
		icmpLayer.SerializeTo(buffer, options)
		break
	case layers.IPProtocolICMPv6:
		icmp6Layer := layers.ICMPv6{
			TypeCode: layers.CreateICMPv6TypeCode(
				event.IcmpType, event.IcmpCode),
		}
		icmp6Layer.SerializeTo(buffer, options)
		break
	default:
		return nil, fmt.Errorf("Unsupported protocol %d.", proto)
	}

	isIp6 := dstIp.To4() == nil

	if !isIp6 {
		ipLayer := layers.IPv4{
			SrcIP:    srcIp,
			DstIP:    dstIp,
			Version:  4,
			Protocol: proto,
			TTL:      64,
		}
		ipLayer.SerializeTo(buffer, options)
	} else {
		ip6Layer := layers.IPv6{
			Version: 6,
			SrcIP:   srcIp,
			DstIP:   dstIp,
		}
		ip6Layer.SerializeTo(buffer, options)
	}

	return pcap.CreatePcap(event.Timestamp.Time,
		buffer.Bytes(), layers.LinkTypeRaw)
}
Beispiel #2
0
func (h *dnsStream) creatPacket(msg_buf []byte, nomalPack chan gopacket.Packet) {
	var sourcePort, DesPort int16
	//read the port from tranport flow
	b_buf := bytes.NewBuffer(h.transport.Src().Raw())
	binary.Read(b_buf, binary.BigEndian, &sourcePort)
	b_buf = bytes.NewBuffer(h.transport.Dst().Raw())
	binary.Read(b_buf, binary.BigEndian, &DesPort)
	//new a UDP layer
	udpLayer := layers.UDP{
		BaseLayer: layers.BaseLayer{
			Contents: []byte{},
			Payload:  msg_buf,
		},
		SrcPort:  layers.UDPPort(sourcePort),
		DstPort:  layers.UDPPort(DesPort),
		Length:   1024,
		Checksum: 30026,
	}
	UDPNewSerializBuffer := gopacket.NewSerializeBuffer() // this buffer could be used as a payload of IP layer
	udpBuffer, _ := UDPNewSerializBuffer.PrependBytes(len(msg_buf))

	copy(udpBuffer, msg_buf)

	ops := gopacket.SerializeOptions{
		FixLengths:       true,
		ComputeChecksums: true,
	}

	if h.net.EndpointType() == layers.EndpointIPv4 {
		ip_checksum := layers.IPv4{}
		ip_checksum.Version = 4
		ip_checksum.TTL = 0
		ip_checksum.SrcIP = h.net.Src().Raw()
		ip_checksum.DstIP = h.net.Dst().Raw()
		udpLayer.SetNetworkLayerForChecksum(&ip_checksum)
	} else {
		ip6_checksum := layers.IPv6{}
		ip6_checksum.Version = 6
		ip6_checksum.NextHeader = layers.IPProtocolNoNextHeader
		ip6_checksum.HopLimit = 0
		ip6_checksum.SrcIP = h.net.Src().Raw()
		ip6_checksum.DstIP = h.net.Dst().Raw()
		udpLayer.SetNetworkLayerForChecksum(&ip6_checksum)
	}
	err := udpLayer.SerializeTo(UDPNewSerializBuffer, ops)
	if err != nil {
		fmt.Print("error in create udp Layer")
		return
		//err = nil
		//	need err handle there
	}

	fmt.Println("finished creat udplayer, the length is ", udpLayer.Length)
	if h.net.EndpointType() == layers.EndpointIPv4 { // if it is from ipv4, construct a ipv4 layer
		ip := layers.IPv4{
			BaseLayer: layers.BaseLayer{
				Contents: []byte{},
				Payload:  UDPNewSerializBuffer.Bytes(),
			},
			Version:    4,
			IHL:        0,
			TOS:        0,
			Length:     0,
			Id:         0,
			Flags:      0,
			FragOffset: 0,
			TTL:        0,
			Protocol:   layers.IPProtocolUDP,
			Checksum:   0,
			SrcIP:      h.net.Src().Raw(),
			DstIP:      h.net.Dst().Raw(),
			Options:    []layers.IPv4Option{},
			Padding:    []byte{},
		}
		//serialize it and use the serilize buffer to new packet
		IPserializeBuffer := gopacket.NewSerializeBuffer()

		ipBuffer, _ := IPserializeBuffer.PrependBytes(len(UDPNewSerializBuffer.Bytes()))
		copy(ipBuffer, UDPNewSerializBuffer.Bytes())
		err = ip.SerializeTo(IPserializeBuffer, ops)
		if err != nil {
			fmt.Print("error in create ipv4 Layer")
			return
			//err = nil
			//	need err handle there
		}

		fmt.Println("finished creat ip, the length is ", ip.Length)
		resultPack := gopacket.NewPacket(IPserializeBuffer.Bytes(), layers.LayerTypeIPv4, gopacket.Default)
		resultPack.Metadata().CaptureLength = len(resultPack.Data())
		resultPack.Metadata().Length = len(resultPack.Data())
		//seems the capture length is 0 so the pcapwrite cannot write it, try to give them a write value
		nomalPack <- resultPack
		return

	} else if h.net.EndpointType() == layers.EndpointIPv6 {
		// if it is in IPV6 contruct ipv6 packet
		ip := layers.IPv6{
			BaseLayer: layers.BaseLayer{
				Contents: []byte{},
				Payload:  UDPNewSerializBuffer.Bytes(),
			},
			Version:      6,
			TrafficClass: 0,
			FlowLabel:    0,
			Length:       0,
			NextHeader:   layers.IPProtocolNoNextHeader, //no sure what next header should be used there
			HopLimit:     0,
			SrcIP:        h.net.Src().Raw(),
			DstIP:        h.net.Dst().Raw(),
			HopByHop:     nil,
			// hbh will be pointed to by HopByHop if that layer exists.
		}
		IPserializeBuffer := gopacket.NewSerializeBuffer()
		err := ip.SerializeTo(IPserializeBuffer, ops)
		if err != nil {
			fmt.Printf("error in creat IPV6 Layer")
			return
		}
		fmt.Println("finished creat ip, the length is ", ip.Length)
		resultPack := gopacket.NewPacket(IPserializeBuffer.Bytes(), layers.LayerTypeIPv6, gopacket.Default)
		resultPack.Metadata().CaptureLength = len(resultPack.Data())
		resultPack.Metadata().Length = len(resultPack.Data())
		//seems the capture length is 0 so the pcapwrite cannot write it, try to give them a write value
		nomalPack <- resultPack
		return
	} else {
		return //unknown network just return?
	}
}