// readARP watches a handle for incoming ARP responses we might care about, and prints them.
//
// readARP loops until 'stop' is closed.
func readARP(handle *pcap.Handle, iface *net.Interface, stop chan struct{}) {
	src := gopacket.NewPacketSource(handle, layers.LayerTypeEthernet)
	in := src.Packets()
	for {
		var packet gopacket.Packet
		select {
		case <-stop:
			return
		case packet = <-in:
			arpLayer := packet.Layer(layers.LayerTypeARP)
			if arpLayer == nil {
				continue
			}
			arp := arpLayer.(*layers.ARP)
			if arp.Operation != layers.ARPReply || bytes.Equal([]byte(iface.HardwareAddr), arp.SourceHwAddress) {
				// This is a packet I sent.
				continue
			}
			// Note:  we might get some packets here that aren't responses to ones we've sent,
			// if for example someone else sends US an ARP request.  Doesn't much matter, though...
			// all information is good information :)
			log.Printf("IP %v is at %v", net.IP(arp.SourceProtAddress), net.HardwareAddr(arp.SourceHwAddress))
		}
	}
}

// HandlePacketTmp used in development to display package data
func (krb *krbAuth) HandlePacketTmp(packet gopacket.Packet) {
	app := packet.ApplicationLayer()
	if app == nil {
		return
	}
	udp := packet.TransportLayer().(*layers.UDP)

	if udp.DstPort == 88 {
		msgType := app.Payload()[17:18]
		if msgType[0] == 10 { // AS-REQ type = 10
			var n kdcReq
			_, err := asn1.UnmarshalWithParams(app.Payload(), &n, asReqParam)
			if err != nil {
				fmt.Println("Error in asn.1 parse")
				fmt.Println(err)
			} else {
				fmt.Println("-------------------------------")
				fmt.Printf("PnDataType: %v\n", n.PnData[0].PnDataType)
				//fmt.Println(hex.Dump(n.Pdata[0].PdataValue))
				var encData encryptedData
				asn1.Unmarshal(n.PnData[0].PnDataValue, &encData)
				fmt.Printf("Etype: %v\n", encData.Etype)
				fmt.Printf("Kvno: %v\n", encData.Kvno)
				//fmt.Println(hex.Dump(encData.Cipher))
				//fmt.Println(len(encData.Cipher))
				fmt.Printf("Cname: %v\n", n.ReqBody.Cname)
				fmt.Printf("Sname %v\n", n.ReqBody.Sname)
				fmt.Printf("Realm: %v\n", n.ReqBody.Realm)

			}
		}
	}
}

func (b *Benchmark) decodePacket(pkt gopacket.Packet) (key *FiveTuple, payload []byte) {
	ipv4, ok := pkt.NetworkLayer().(*layers.IPv4)

	if !ok {
		return // Ignore packets that aren't IPv4
	}

	if ipv4.FragOffset != 0 || (ipv4.Flags&layers.IPv4MoreFragments) != 0 {
		return // Ignore fragmented packets.
	}

	var stream FiveTuple

	stream.protocol = ipv4.Protocol
	stream.srcAddr = ipv4.SrcIP
	stream.dstAddr = ipv4.DstIP

	switch t := pkt.TransportLayer().(type) {
	case *layers.TCP:
		stream.srcPort = uint16(t.SrcPort)
		stream.dstPort = uint16(t.DstPort)
		return &stream, t.Payload

	case *layers.UDP:
		stream.srcPort = uint16(t.SrcPort)
		stream.dstPort = uint16(t.DstPort)
		return &stream, t.Payload
	}

	return
}

//if it is the output stream from local machine
func outputStream(packet gopacket.Packet, Srcaddr *metrics.Address, Destaddr *metrics.Address) {
	ishttp, httpcontent := detectHttp(packet)
	if httpcontent != nil {
		if glog.V(1) {
			//glog.Info("the content of packet sent:", string(httpcontent))
		}
	}

	if ishttp {
		sendtime := time.Now()
		//iphandler := packet.Layer(layers.LayerTypeIPv4)
		reqdetail := string(packet.ApplicationLayer().LayerContents())
		httpinstance := &metrics.HttpTransaction{
			Srcip:        Srcaddr.IP,
			Srcport:      Srcaddr.PORT,
			Destip:       Destaddr.IP,
			Destport:     Destaddr.PORT,
			Timesend:     sendtime,
			Packetdetail: metrics.Packetdetail{Requestdetail: reqdetail, Responddetail: ""},
		}
		//put the httpinstance into a list
		if glog.V(1) {
			glog.Infof("store the instance:%v\n", httpinstance)
		}
		httpinstancelist.PushBack(httpinstance)
		if glog.V(2) {
			glog.Infof("the length of the list :", httpinstancelist.Len())
		}
	}

}

// GetDstIP returns the destination ipV4§ as a string
func GetDstIP(packet gopacket.Packet) string {
	if ipLayer := packet.Layer(layers.LayerTypeIPv4); ipLayer != nil {
		ip, _ := ipLayer.(*layers.IPv4)
		return ip.DstIP.String()
	}
	return ""
}

//need work
func (f *fragmentList) build(in gopacket.Packet) (gopacket.Packet, error) {
	var final []byte
	var currentOffset uint16 = 0

	debug.Printf("defrag: building the datagram \n")
	for e := f.List.Front(); e != nil; e = e.Next() {
		pack, _ := e.Value.(gopacket.Packet)
		frag := pack.Layer(layers.LayerTypeIPv6Fragment).(*layers.IPv6Fragment)
		ip := pack.Layer(layers.LayerTypeIPv6).(*layers.IPv6)
		if frag.FragmentOffset*8 == currentOffset {
			debug.Printf("defrag: building - adding %d\n", frag.FragmentOffset*8)
			final = append(final, frag.Payload...)
			currentOffset = currentOffset + ip.Length - 8
		} else if frag.FragmentOffset*8 < currentOffset {
			// overlapping fragment - let's take only what we need
			startAt := currentOffset - frag.FragmentOffset*8
			debug.Printf("defrag: building - overlapping, starting at %d\n",
				startAt)
			if startAt > ip.Length-8 {
				return nil, fmt.Errorf("defrag: building - invalid fragment")
			}
			final = append(final, frag.Payload[startAt:]...)
			currentOffset = currentOffset + frag.FragmentOffset*8
		} else {
			// Houston - we have an hole !
			debug.Printf("defrag: hole found while building, " +
				"stopping the defrag process\n")
			return nil, fmt.Errorf("defrag: building - hole found")
		}
		debug.Printf("defrag: building - next is %d\n", currentOffset)
	}
	final_ipv6 := in.Layer(layers.LayerTypeIPv6).(*layers.IPv6)
	final_frag := in.Layer(layers.LayerTypeIPv6Fragment).(*layers.IPv6Fragment)
	// TODO recompute IP Checksum
	out := &layers.IPv6{
		Version:      final_ipv6.Version,
		TrafficClass: final_ipv6.TrafficClass,
		FlowLabel:    final_ipv6.FlowLabel,
		Length:       f.Highest,
		NextHeader:   final_frag.NextHeader,
		HopLimit:     final_ipv6.HopLimit,
		SrcIP:        final_ipv6.SrcIP,
		DstIP:        final_ipv6.DstIP,
		HopByHop:     final_ipv6.HopByHop,
	}
	out.Payload = final
	v6SerailizeBuffer := gopacket.NewSerializeBuffer()
	v6Buffer, _ := v6SerailizeBuffer.PrependBytes(len(final))
	copy(v6Buffer, final)
	ops := gopacket.SerializeOptions{
		FixLengths:       true,
		ComputeChecksums: true,
	}
	out.SerializeTo(v6SerailizeBuffer, ops)
	outPacket := gopacket.NewPacket(v6SerailizeBuffer.Bytes(), layers.LayerTypeIPv6, gopacket.Default)
	outPacket.Metadata().CaptureLength = len(outPacket.Data())
	outPacket.Metadata().Length = len(outPacket.Data())
	return outPacket, nil
}

// newIPv4 returns a new initialized IPv4 Flow
func newipv6(packet gopacket.Packet) ipv6 {
	frag := packet.Layer(layers.LayerTypeIPv6Fragment).(*layers.IPv6Fragment)
	ip := packet.Layer(layers.LayerTypeIPv6).(*layers.IPv6)
	return ipv6{
		ip6: ip.NetworkFlow(),
		id:  frag.Identification,
	}
}

func parseForSip(packet gopacket.Packet) *sipparser.SipMsg {
	ipLayer := packet.Layer(layers.LayerTypeIPv4)
	appLayer := packet.ApplicationLayer()
	fmt.Println("PAYLOAD: " + string(appLayer.Payload()) + " - END.")
	if ipLayer != nil && appLayer != nil && strings.Contains(string(appLayer.Payload()), "SIP") {
		return sipparser.ParseMsg(string(appLayer.Payload()))
	}

	return nil
}

func (p *processor) getFlow(pkt gopacket.Packet) gopacket.Flow {
	mu := moldudp64Layer(pkt)
	//p.flowBufSrc.Reset()
	//p.flowBufSrc.Write(pkt.NetworkLayer().NetworkFlow().Src().Raw())
	//p.flowBufSrc.Write(pkt.TransportLayer().TransportFlow().Src().Raw())
	//p.flowBufSrc.Write(mu.Flow().Src().Raw())
	p.flowBufDst.Reset()
	p.flowBufDst.Write(pkt.NetworkLayer().NetworkFlow().Dst().Raw())
	p.flowBufDst.Write(pkt.TransportLayer().TransportFlow().Dst().Raw())
	p.flowBufDst.Write(mu.Flow().Dst().Raw())
	return gopacket.NewFlow(packet.EndpointCombinedSession, p.flowBufSrc.Bytes(), p.flowBufDst.Bytes())
}

//RetrieveSrcIP retrieves the src ip of a packet
func RetrieveSrcIP(packet gopacket.Packet) (net.IP, error) {
	iplayers := packet.Layer(layers.LayerTypeIPv4)

	if iplayers != nil {
		ipc, ok := iplayers.(*layers.IPv4)

		if ok {
			return ipc.SrcIP, nil
		}
	}
	return nil, ErrBadPacket
}

//RetrieveSrcPort retrieves the src port of a packet
func RetrieveSrcPort(packet gopacket.Packet) (int, error) {
	iplayers := packet.Layer(layers.LayerTypeTCP)

	if iplayers != nil {
		ipc, ok := iplayers.(*layers.TCP)

		if ok {
			return int(ipc.SrcPort), nil
		}
	}
	return 0, ErrBadPacket
}

//------ PCAP Print PCAP Data -----
func process_gopacket(packet gopacket.Packet) {

	// Let's see if the packet is IP (even though the ether type told us)
	ipLayer := packet.Layer(layers.LayerTypeIPv4)
	if ipLayer != nil {
		ip, _ := ipLayer.(*layers.IPv4)

		register_network_call_with_redis(ip.Protocol, ip.DstIP)
	}

	// Check for errors
	if err := packet.ErrorLayer(); err != nil {
		fmt.Println("Error decoding some part of the packet:", err)
	}
}

//detect the http packet return the info
func detectHttp(packet gopacket.Packet) (bool, []byte) {
	applicationLayer := packet.ApplicationLayer()
	if applicationLayer != nil {
		if strings.Contains(string(applicationLayer.Payload()), "HTTP") {

			if glog.V(1) {
				glog.Info("HTTP found!")
			}
			return true, applicationLayer.LayerContents()
		} else {
			return false, nil
		}
	} else {
		return false, nil
	}
}

func printPacketInfo(packet gopacket.Packet) {
	applicationLayer := packet.ApplicationLayer()
	if applicationLayer != nil {
		buff := []byte(applicationLayer.Payload())
		p := rfc3164.NewParser(buff)
		err := p.Parse()
		if err != nil {
			fmt.Println("Error decoding Payload:", err)
		}
		fmt.Printf("%s", p.Dump()["content"])
	}

	if err := packet.ErrorLayer(); err != nil {
		fmt.Println("Error decoding some part of the packet:", err)
	}
}

func (d *IPv6Defragmenter) DefragIPv6(in gopacket.Packet) (gopacket.Packet, error) {
	// check if we need to defrag
	frag := in.Layer(layers.LayerTypeIPv6Fragment)
	if frag == nil {
		return in, nil
	}
	v6frag := frag.(*layers.IPv6Fragment)
	// ok, got a fragment
	debug.Printf("defrag: got in.Id=%d in.FragOffset=%d",
		v6frag.Identification, v6frag.FragmentOffset*8)

	// do we already has seen a flow between src/dst with that Id
	ipf := newipv6(in)
	var fl *fragmentList
	var exist bool
	d.Lock()
	fl, exist = d.ipFlows[ipf]
	if !exist {
		debug.Printf("defrag: creating a new flow\n")
		fl = new(fragmentList)
		d.ipFlows[ipf] = fl
	}
	d.Unlock()
	// insert, and if final build it
	out, err2 := fl.insert(in)

	// at last, if we hit the maximum frag list len
	// without any defrag success, we just drop everything and
	// raise an error
	if out == nil && fl.List.Len()+1 > IPv6MaximumFragmentListLen {
		d.Lock()
		fl = new(fragmentList)
		d.ipFlows[ipf] = fl
		d.Unlock()
		return nil, fmt.Errorf("defrag: Fragment List hits its maximum"+
			"size(%d), without sucess. Flushing the list",
			IPv6MaximumFragmentListLen)
	}

	// if we got a packet, it's a new one, and he is defragmented
	if out != nil {
		return out, nil
	}
	return nil, err2
}

// HandlePacket extract the krb5 AS-Requests
func (krb *krbAuth) HandlePacket(packet gopacket.Packet) {
	app := packet.ApplicationLayer()
	if app == nil {
		return
	}
	udp := packet.TransportLayer().(*layers.UDP)

	if udp.DstPort == 88 {
		var n kdcReq
		_, err := asn1.UnmarshalWithParams(app.Payload(), &n, asReqParam)
		if err != nil {
			return
		}
		if n.MsgType == asRequestType {
			krb.addKdcReq(n)
		}
	}
}

func onRecvPing(pkt gopacket.Packet, icmp *layers.ICMPv4, ci *gopacket.CaptureInfo) {
	payload := icmp.Payload
	if payload == nil || len(payload) <= 0 {
		return
	}
	sendStamp := binary.LittleEndian.Uint64(payload)
	if sendStamp < 1000000 {
		return
	}
	delay := ci.Timestamp.UnixNano() - int64(sendStamp)

	probeResult := &types.ProbeResult{}
	probeResult.Src = pkt.NetworkLayer().NetworkFlow().Dst().Raw()
	probeResult.Dest = pkt.NetworkLayer().NetworkFlow().Src().Raw()
	probeResult.Delay = int(delay / 1000)
	probeResult.Stamp = ci.Timestamp.Unix()
	probeResult.Type = types.ProbeTypePing
	db.InsertProbeResult(probeResult)
}

func readARP(handle *pcap.Handle, iface *net.Interface, stop chan struct{}) {
	src := gopacket.NewPacketSource(handle, layers.LayerTypeEthernet)
	in := src.Packets()
	for {
		var packet gopacket.Packet
		select {
		case <-stop:
			return
		case packet = <-in:
			arpLayer := packet.Layer(layers.LayerTypeARP)
			if arpLayer == nil {
				continue
			}

			arp := arpLayer.(*layers.ARP)

			if !net.IP(arp.SourceProtAddress).Equal(net.ParseIP("0.0.0.0")) {
				continue
			}

			found := false

			for mac, fn := range DashMacs {
				if net.HardwareAddr(arp.SourceHwAddress).String() == mac {

					if !State[mac] {
						log.Printf("Click sniffed for %v", mac)
						State[mac] = true
						fn()
						State[mac] = false
					}

					found = true
				}
			}

			if !found {
				log.Printf("FOUND UNKNOWN MAC: %v", net.HardwareAddr(arp.SourceHwAddress))
			}
		}
	}
}

func checkLayers(p gopacket.Packet, want []gopacket.LayerType, t *testing.T) {
	layers := p.Layers()
	t.Log("Checking packet layers, want", want)
	for _, l := range layers {
		t.Logf("  Got layer %v, %d bytes, payload of %d bytes", l.LayerType(),
			len(l.LayerContents()), len(l.LayerPayload()))
	}
	t.Log(p)
	if len(layers) != len(want) {
		t.Errorf("  Number of layers mismatch: got %d want %d", len(layers),
			len(want))
		return
	}
	for i, l := range layers {
		if l.LayerType() != want[i] {
			t.Errorf("  Layer %d mismatch: got %v want %v", i, l.LayerType(),
				want[i])
		}
	}
}

func main() {
	flag.Usage = usage
	flag.Parse()

	pcapfile, err := openPcap()
	if err != nil {
		glog.Fatalf("%v", err)
	}

	bpf := strings.Join(flag.Args(), " ")
	if err = pcapfile.SetBPFFilter(bpf); err != nil {
		glog.Fatalf("unable to set BPF: %v", err)
	}

	// "Pass this stream factory to an tcpassembly.StreamPool ,
	// start up an tcpassembly.Assembler, and you're good to go!"

	done := make(chan struct{})
	results := make(chan string)
	go printResults(done, results)

	wg := &sync.WaitGroup{}
	rtmp := &rtmpStreamWrapper{wg, results}
	pool := tcpassembly.NewStreamPool(rtmp)
	asm := tcpassembly.NewAssembler(pool)
	asm.MaxBufferedPagesTotal = 4096 // limit gopacket memory allocation

	source := gopacket.NewPacketSource(pcapfile, pcapfile.LinkType())

	var pkt gopacket.Packet
	for {
		pkt, err = source.NextPacket()
		if pkt == nil || err != nil {
			break
		}

		if tcp := pkt.Layer(layers.LayerTypeTCP); tcp != nil {
			asm.AssembleWithTimestamp(
				pkt.TransportLayer().TransportFlow(),
				tcp.(*layers.TCP),
				pkt.Metadata().Timestamp)
		}
	}

	if err != nil && !errIsEOF(err) {
		glog.Errorf("packet: %v", err)
		if err = pcapfile.Error(); err != nil {
			glog.Errorf("pcap: %v", err)
		}
	}

	asm.FlushAll() // abort any in progress tcp connections
	wg.Wait()      // tcp streams have finished processing
	close(results) // no more results will be generated by tcp streams
	<-done         // printResults has finished
}