Golang TCP.SetNetworkLayerForChecksum方法代碼示例

func makeTestPacket() []byte {
	var testSeq uint32 = 12345
	buf := gopacket.NewSerializeBuffer()
	opts := gopacket.SerializeOptions{
		FixLengths:       true,
		ComputeChecksums: true,
	}
	eth := layers.Ethernet{
		SrcMAC: net.HardwareAddr{0xde, 0xad, 0xbe, 0xee, 0xee, 0xff},
		DstMAC: net.HardwareAddr{0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
	}
	ip := layers.IPv4{
		SrcIP:    net.IP{1, 2, 3, 4},
		DstIP:    net.IP{2, 3, 4, 5},
		Version:  4,
		TTL:      64,
		Protocol: layers.IPProtocolTCP,
	}
	tcp := layers.TCP{
		SYN:       true,
		SrcPort:   1,
		DstPort:   2,
		Seq:       testSeq,
		BaseLayer: layers.BaseLayer{Payload: []byte{1, 2, 3}},
	}
	tcp.SetNetworkLayerForChecksum(&ip)
	gopacket.SerializeLayers(buf, opts, &eth, &ip, &tcp)
	packetData := buf.Bytes()
	return packetData
}

func TestGetOverlapRingsWithZeroRings(t *testing.T) {
	ip := layers.IPv4{
		SrcIP:    net.IP{1, 2, 3, 4},
		DstIP:    net.IP{2, 3, 4, 5},
		Version:  4,
		TTL:      64,
		Protocol: layers.IPProtocolTCP,
	}
	tcp := layers.TCP{
		SYN:     true,
		SrcPort: 1,
		DstPort: 2,
	}
	tcp.SetNetworkLayerForChecksum(&ip)
	payload := gopacket.Payload([]byte{1, 2, 3, 4})
	p := types.PacketManifest{
		IP:      ip,
		TCP:     tcp,
		Payload: payload,
	}
	options := ConnectionOptions{
		MaxBufferedPagesTotal:         0,
		MaxBufferedPagesPerConnection: 0,
		MaxRingPackets:                40,
		PageCache:                     nil,
		LogDir:                        "fake-log-dir",
	}

	f := &DefaultConnFactory{}
	conn := f.Build(options).(*Connection)

	ipFlow, _ := gopacket.FlowFromEndpoints(layers.NewIPEndpoint(net.IPv4(1, 2, 3, 4)), layers.NewIPEndpoint(net.IPv4(2, 3, 4, 5)))
	tcpFlow, _ := gopacket.FlowFromEndpoints(layers.NewTCPPortEndpoint(layers.TCPPort(1)), layers.NewTCPPortEndpoint(layers.TCPPort(2)))
	serverFlow := types.NewTcpIpFlowFromFlows(ipFlow, tcpFlow)
	clientFlow := serverFlow.Reverse()
	conn.serverFlow = serverFlow
	conn.clientFlow = clientFlow

	head, tail := getOverlapRings(&p, serverFlow, conn.ClientStreamRing)
	if head == nil || tail == nil {
		return
	} else {
		t.Fail()
	}
	return
}

func sendPacket(handle *pcap.Handle, sMac, dMac net.HardwareAddr, sIp, dIp net.IP, sPort, dPort layers.TCPPort, IpId uint16, IpTtl uint8, TcpSeq, ack uint32, WindowsSize uint16, data []byte) error {
	eth := layers.Ethernet{
		SrcMAC:       sMac,
		DstMAC:       dMac,
		EthernetType: layers.EthernetTypeIPv4,
	}
	ip4 := layers.IPv4{
		SrcIP:    sIp,
		DstIP:    dIp,
		Id:       IpId,
		Flags:    layers.IPv4DontFragment,
		Version:  4,
		TTL:      IpTtl,
		Protocol: layers.IPProtocolTCP,
	}
	tcp := layers.TCP{
		SrcPort: sPort,
		DstPort: dPort,
		Seq:     TcpSeq,
		ACK:     true,
		Ack:     ack,
		Window:  WindowsSize,
		PSH:     true, // 立刻處理
	}

	if len(data) == 0 {
		tcp.RST = true
	}

	tcp.SetNetworkLayerForChecksum(&ip4)

	buf := gopacket.NewSerializeBuffer()
	opts := gopacket.SerializeOptions{
		FixLengths:       true,
		ComputeChecksums: true,
	}

	payload := gopacket.Payload(data)

	if err := gopacket.SerializeLayers(buf, opts, &eth, &ip4, &tcp, payload); err != nil {
		return err
	}

	return handle.WritePacketData(buf.Bytes())
}

func (r *RawSocketServer) injectPacketFromDst(tcpLayer *layers.TCP, rawBytes []byte) error {
	// Preparing ipLayer.
	ipLayer := &layers.IPv4{
		SrcIP:    r.dst.ip,
		DstIP:    r.src.ip,
		Version:  4,
		TTL:      64,
		Protocol: layers.IPProtocolTCP,
	}

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

	tcpLayer.SrcPort = r.dst.port
	tcpLayer.DstPort = r.src.port
	tcpLayer.Window = r.window

	tcpLayer.Ack = r.ack
	tcpLayer.Seq = r.seq

	tcpLayer.SetNetworkLayerForChecksum(ipLayer)

	// And create the packet with the layers
	buffer := gopacket.NewSerializeBuffer()
	gopacket.SerializeLayers(buffer, options,
		ipLayer,
		tcpLayer,
		gopacket.Payload(rawBytes),
	)

	outgoingPacket := buffer.Bytes()

	p := tuntap.Packet{
		Protocol:  0x800,
		Truncated: false,
		Packet:    outgoingPacket,
	}

	return r.iface.WritePacket(&p)
}

func TestNewTcpIpFlowFromPacket(t *testing.T) {
	buf := gopacket.NewSerializeBuffer()
	opts := gopacket.SerializeOptions{
		FixLengths:       true,
		ComputeChecksums: true,
	}
	ip := layers.IPv4{
		SrcIP:    net.IP{1, 2, 3, 4},
		DstIP:    net.IP{2, 3, 4, 5},
		Version:  4,
		TTL:      64,
		Protocol: layers.IPProtocolTCP,
	}
	tcp := layers.TCP{
		SYN:       true,
		SrcPort:   1,
		DstPort:   2,
		Seq:       123,
		BaseLayer: layers.BaseLayer{Payload: []byte{1, 2, 3}},
	}
	tcp.SetNetworkLayerForChecksum(&ip)
	gopacket.SerializeLayers(buf, opts, &ip, &tcp)
	packetData := buf.Bytes()
	flow1, err := NewTcpIpFlowFromPacket(packetData)

	ipFlow2, _ := gopacket.FlowFromEndpoints(layers.NewIPEndpoint(net.IPv4(1, 2, 3, 4)), layers.NewIPEndpoint(net.IPv4(2, 3, 4, 5)))
	tcpFlow2, _ := gopacket.FlowFromEndpoints(layers.NewTCPPortEndpoint(layers.TCPPort(1)), layers.NewTCPPortEndpoint(layers.TCPPort(2)))
	flow2 := NewTcpIpFlowFromFlows(ipFlow2, tcpFlow2)

	if err != nil && !flow2.Equal(flow1) {
		t.Error("NewTcpIpFlowFromPacket fail")
		t.Fail()
	}

	flow1, err = NewTcpIpFlowFromPacket([]byte{1, 2, 3, 4, 5, 6, 7})
	if err == nil || !flow1.Equal(&TcpIpFlow{}) {
		t.Error("NewTcpIpFlowFromPacket fail")
		t.Fail()
	}
}

func TestSequenceFromPacket(t *testing.T) {
	var testSeq uint32 = 12345
	buf := gopacket.NewSerializeBuffer()
	opts := gopacket.SerializeOptions{
		FixLengths:       true,
		ComputeChecksums: true,
	}
	ip := layers.IPv4{
		SrcIP:    net.IP{1, 2, 3, 4},
		DstIP:    net.IP{2, 3, 4, 5},
		Version:  4,
		TTL:      64,
		Protocol: layers.IPProtocolTCP,
	}
	tcp := layers.TCP{
		SYN:       true,
		SrcPort:   1,
		DstPort:   2,
		Seq:       testSeq,
		BaseLayer: layers.BaseLayer{Payload: []byte{1, 2, 3}},
	}
	tcp.SetNetworkLayerForChecksum(&ip)
	gopacket.SerializeLayers(buf, opts, &ip, &tcp)
	packetData := buf.Bytes()
	seq, err := SequenceFromPacket(packetData)
	if err != nil && seq != testSeq {
		t.Error("SequenceFromPacket failed")
		t.Fail()
	}

	seq, err = SequenceFromPacket([]byte{1, 2, 3})
	if err == nil {
		t.Error("SequenceFromPacket should have failed")
		t.Fail()
	}
}

// scan scans the dst IP address of this scanner.
func (s *scanner) scan() error {
	// First off, get the MAC address we should be sending packets to.
	hwaddr, err := s.getHwAddr()
	if err != nil {
		return err
	}
	// Construct all the network layers we need.
	eth := layers.Ethernet{
		SrcMAC:       s.iface.HardwareAddr,
		DstMAC:       hwaddr,
		EthernetType: layers.EthernetTypeIPv4,
	}
	ip4 := layers.IPv4{
		SrcIP:    s.src,
		DstIP:    s.dst,
		Version:  4,
		TTL:      64,
		Protocol: layers.IPProtocolTCP,
	}
	tcp := layers.TCP{
		SrcPort: 54321,
		DstPort: 0, // will be incremented during the scan
		SYN:     true,
	}
	tcp.SetNetworkLayerForChecksum(&ip4)

	// Create the flow we expect returning packets to have, so we can check
	// against it and discard useless packets.
	ipFlow := gopacket.NewFlow(layers.EndpointIPv4, s.dst, s.src)
	start := time.Now()
	for {
		// Send one packet per loop iteration until we've sent packets
		// to all of ports [1, 65535].
		if tcp.DstPort < 65535 {
			start = time.Now()
			tcp.DstPort++
			if err := s.send(&eth, &ip4, &tcp); err != nil {
				log.Printf("error sending to port %v: %v", tcp.DstPort, err)
			}
		}
		// Time out 5 seconds after the last packet we sent.
		if time.Since(start) > time.Second*5 {
			log.Printf("timed out for %v, assuming we've seen all we can", s.dst)
			return nil
		}

		// Read in the next packet.
		data, _, err := s.handle.ReadPacketData()
		if err == pcap.NextErrorTimeoutExpired {
			continue
		} else if err != nil {
			log.Printf("error reading packet: %v", err)
			continue
		}

		// Parse the packet.  We'd use DecodingLayerParser here if we
		// wanted to be really fast.
		packet := gopacket.NewPacket(data, layers.LayerTypeEthernet, gopacket.NoCopy)

		// Find the packets we care about, and print out logging
		// information about them.  All others are ignored.
		if net := packet.NetworkLayer(); net == nil {
			// log.Printf("packet has no network layer")
		} else if net.NetworkFlow() != ipFlow {
			// log.Printf("packet does not match our ip src/dst")
		} else if tcpLayer := packet.Layer(layers.LayerTypeTCP); tcpLayer == nil {
			// log.Printf("packet has not tcp layer")
		} else if tcp, ok := tcpLayer.(*layers.TCP); !ok {
			// We panic here because this is guaranteed to never
			// happen.
			panic("tcp layer is not tcp layer :-/")
		} else if tcp.DstPort != 54321 {
			// log.Printf("dst port %v does not match", tcp.DstPort)
		} else if tcp.RST {
			log.Printf("  port %v closed", tcp.SrcPort)
		} else if tcp.SYN && tcp.ACK {
			log.Printf("  port %v open", tcp.SrcPort)
		} else {
			// log.Printf("ignoring useless packet")
		}
	}
}

func TestTCPHijack(t *testing.T) {
	attackLogger := NewDummyAttackLogger()
	options := ConnectionOptions{
		MaxBufferedPagesTotal:         0,
		MaxBufferedPagesPerConnection: 0,
		MaxRingPackets:                40,
		PageCache:                     nil,
		LogDir:                        "fake-log-dir",
		DetectHijack:                  true,
	}

	f := &DefaultConnFactory{}
	conn := f.Build(options).(*Connection)
	conn.AttackLogger = attackLogger

	ip := layers.IPv4{
		SrcIP:    net.IP{1, 2, 3, 4},
		DstIP:    net.IP{2, 3, 4, 5},
		Version:  4,
		TTL:      64,
		Protocol: layers.IPProtocolTCP,
	}
	tcp := layers.TCP{
		Seq:     3,
		SYN:     true,
		ACK:     false,
		SrcPort: 1,
		DstPort: 2,
	}

	ipFlow, _ := gopacket.FlowFromEndpoints(layers.NewIPEndpoint(net.IPv4(1, 2, 3, 4)), layers.NewIPEndpoint(net.IPv4(2, 3, 4, 5)))
	tcpFlow, _ := gopacket.FlowFromEndpoints(layers.NewTCPPortEndpoint(layers.TCPPort(1)), layers.NewTCPPortEndpoint(layers.TCPPort(2)))
	flow := types.NewTcpIpFlowFromFlows(ipFlow, tcpFlow)

	p := types.PacketManifest{
		Timestamp: time.Now(),
		Flow:      flow,
		IP:        ip,
		TCP:       tcp,
		Payload:   []byte{},
	}
	tcp.SetNetworkLayerForChecksum(&ip)
	flowReversed := flow.Reverse()

	conn.clientFlow = flow
	conn.serverFlow = flowReversed

	conn.ReceivePacket(&p)

	if conn.state != TCP_CONNECTION_REQUEST {
		t.Error("invalid state transition\n")
		t.Fail()
	}

	// next state transition test
	ip = layers.IPv4{
		SrcIP:    net.IP{2, 3, 4, 5},
		DstIP:    net.IP{1, 2, 3, 4},
		Version:  4,
		TTL:      64,
		Protocol: layers.IPProtocolTCP,
	}
	tcp = layers.TCP{
		Seq:     9,
		SYN:     true,
		ACK:     true,
		Ack:     4,
		SrcPort: 2,
		DstPort: 1,
	}
	p = types.PacketManifest{
		Timestamp: time.Now(),
		Flow:      flowReversed,
		IP:        ip,
		TCP:       tcp,
		Payload:   []byte{},
	}
	conn.ReceivePacket(&p)

	if conn.state != TCP_CONNECTION_ESTABLISHED {
		t.Errorf("invalid state transition: current state %d\n", conn.state)
		t.Fail()
	}

	// test hijack in TCP_CONNECTION_ESTABLISHED state
	ip = layers.IPv4{
		SrcIP:    net.IP{2, 3, 4, 5},
		DstIP:    net.IP{1, 2, 3, 4},
		Version:  4,
		TTL:      64,
		Protocol: layers.IPProtocolTCP,
	}
	tcp = layers.TCP{
		Seq:     6699,
		SYN:     true,
		ACK:     true,
		Ack:     4,
		SrcPort: 2,
		DstPort: 1,
	}
//.........這裏部分代碼省略.........

//.........這裏部分代碼省略.........
			if gateway == nil || !gateway.Up {
				log.Printf("no gateway")
				// ignore
				return
			}

			if dstIP.To4() != nil {
				if len(gateway.IPv4Addrs) > 0 {
					ruleDstIP = gateway.IPv4Addrs[0]
				}
			} else {
				if len(gateway.IPv6Addrs) > 0 {
					ruleDstIP = gateway.IPv6Addrs[0]
				}
			}
		}
		if ruleDstIP == nil {
			log.Printf("no destination ip")
			// ignore
			return
		}

		var r routes.Route
		r.Protocol = protocols.TCP
		r.HostID = pkt.DstHost.ID
		r.SetInboundSource(srcIP, srcPort)
		r.SetInboundDestination(dstIP, dstPort)
		r.SetOutboundSource(hostIP, hostPort)
		r.SetOutboundDestination(ruleDstIP, ruleDstPort)
		route, err = vnet.routes.AddRoute(&r)
		if err != nil {
			// ignore
			log.Printf("TCP/error: %s", err)
			return
		}
	}

	if route == nil {
		log.Printf("no route")
		// ignore
		return
	}

	var (
		eth layers.Ethernet
		tcp layers.TCP
	)

	eth = *pkt.Eth
	eth.SrcMAC = vnet.system.ControllerMAC()
	eth.DstMAC = vnet.system.GatewayMAC()

	tcp = *pkt.TCP
	tcp.SrcPort = layers.TCPPort(route.Outbound.SrcPort)
	tcp.DstPort = layers.TCPPort(route.Outbound.DstPort)

	if route.Outbound.DstIP.To4() != nil {
		ip := layers.IPv4{
			SrcIP:    route.Outbound.SrcIP.To4(),
			DstIP:    route.Outbound.DstIP.To4(),
			Version:  4,
			Protocol: layers.IPProtocolTCP,
			TTL:      64,
		}

		tcp.SetNetworkLayerForChecksum(&ip)

		err = vnet.writePacket(
			&eth,
			&ip,
			&tcp,
			gopacket.Payload(pkt.TCP.Payload))
		if err != nil {
			log.Printf("TCP/error: %s", err)
			return
		}

	} else {
		ip := layers.IPv6{
			SrcIP:      route.Outbound.SrcIP.To16(),
			DstIP:      route.Outbound.DstIP.To16(),
			Version:    4,
			NextHeader: layers.IPProtocolTCP,
		}

		tcp.SetNetworkLayerForChecksum(&ip)

		err = vnet.writePacket(
			&eth,
			&ip,
			&tcp,
			gopacket.Payload(pkt.TCP.Payload))
		if err != nil {
			log.Printf("TCP/error: %s", err)
			return
		}
	}

	route.RoutedPacket(now, len(pkt.buf))
}

func main() {
	defer util.Run()()
	var handle *pcap.Handle
	var err error
	if *fname != "" {
		if handle, err = pcap.OpenOffline(*fname); err != nil {
			log.Fatal("PCAP OpenOffline error:", err)
		}
	} else {
		// This is a little complicated because we want to allow all possible options
		// for creating the packet capture handle... instead of all this you can
		// just call pcap.OpenLive if you want a simple handle.
		inactive, err := pcap.NewInactiveHandle(*iface)
		if err != nil {
			log.Fatal("could not create: %v", err)
		}
		defer inactive.CleanUp()
		if err = inactive.SetSnapLen(*snaplen); err != nil {
			log.Fatal("could not set snap length: %v", err)
		} else if err = inactive.SetPromisc(*promisc); err != nil {
			log.Fatal("could not set promisc mode: %v", err)
		} else if err = inactive.SetTimeout(time.Second); err != nil {
			log.Fatal("could not set timeout: %v", err)
		}
		if *tstype != "" {
			if t, err := pcap.TimestampSourceFromString(*tstype); err != nil {
				log.Fatalf("Supported timestamp types: %v", inactive.SupportedTimestamps())
			} else if err := inactive.SetTimestampSource(t); err != nil {
				log.Fatalf("Supported timestamp types: %v", inactive.SupportedTimestamps())
			}
		}
		inactive.SetImmediateMode(true)
		if handle, err = inactive.Activate(); err != nil {
			log.Fatal("PCAP Activate error:", err)
		}
		defer handle.Close()
		if len(flag.Args()) > 0 {
			bpffilter := strings.Join(flag.Args(), " ")
			fmt.Fprintf(os.Stderr, "Using BPF filter %q\n", bpffilter)
			if err = handle.SetBPFFilter(bpffilter); err != nil {
				log.Fatal("BPF filter error:", err)
			}
		}
	}

	packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
	for packet := range packetSource.Packets() {
		if tcpLayer := packet.Layer(layers.LayerTypeTCP); tcpLayer != nil {
			if tcpLayer.(*layers.TCP).DstPort != 80 {
				continue
			}
			if tcpLayer.(*layers.TCP).SYN || tcpLayer.(*layers.TCP).RST {
				continue
			}
			data := string(tcpLayer.(*layers.TCP).LayerPayload())
			if !strings.HasPrefix(data, "GET") {
				continue
			}
			fmt.Println("I got GET packet!")
			ethLayer := packet.Layer(layers.LayerTypeEthernet)
			eth := layers.Ethernet{
				SrcMAC:       ethLayer.(*layers.Ethernet).DstMAC,
				DstMAC:       ethLayer.(*layers.Ethernet).SrcMAC,
				EthernetType: layers.EthernetTypeIPv4,
			}
			ipv4Layer := packet.Layer(layers.LayerTypeIPv4)
			ipv4 := layers.IPv4{
				Version:  ipv4Layer.(*layers.IPv4).Version,
				SrcIP:    ipv4Layer.(*layers.IPv4).DstIP,
				DstIP:    ipv4Layer.(*layers.IPv4).SrcIP,
				TTL:      77,
				Id:       ipv4Layer.(*layers.IPv4).Id,
				Protocol: layers.IPProtocolTCP,
			}
			tcp := layers.TCP{
				SrcPort: tcpLayer.(*layers.TCP).DstPort,
				DstPort: tcpLayer.(*layers.TCP).SrcPort,
				PSH:     true,
				ACK:     true,
				FIN:     true,
				Seq:     tcpLayer.(*layers.TCP).Ack,
				Ack:     tcpLayer.(*layers.TCP).Seq + uint32(len(data)),
				Window:  0,
			}
			tcp.SetNetworkLayerForChecksum(&ipv4)
			data =
				`HTTP/1.1 200 OK
Server: nginx
Date: Tue, 26 Jan 2016 13:09:19 GMT
Content-Type: text/plain;charset=UTF-8
Connection: keep-alive
Vary: Accept-Encoding
Cache-Control: no-store
Pragrma: no-cache
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Cache-Control: no-cache
Content-Length: 7

Stupid!`

//.........這裏部分代碼省略.........