Exemplo n.º 1
0
func testReadSequence(t *testing.T, lossErrors bool, readSize int, seq readSequence) {
	f := &testReaderFactory{ReaderStream: NewReaderStream()}
	f.ReaderStream.LossErrors = lossErrors
	p := tcpassembly.NewStreamPool(f)
	a := tcpassembly.NewAssembler(p)
	buf := make([]byte, readSize)
	go func() {
		for i, test := range seq.in {
			fmt.Println("Assembling", i)
			a.Assemble(netFlow, &test)
			fmt.Println("Assembly done")
		}
	}()
	for i, test := range seq.want {
		fmt.Println("Waiting for read", i)
		n, err := f.Read(buf[:])
		fmt.Println("Got read")
		if n != len(test.data) {
			t.Errorf("test %d want %d bytes, got %d bytes", i, len(test.data), n)
		} else if err != test.err {
			t.Errorf("test %d want err %v, got err %v", i, test.err, err)
		} else if !bytes.Equal(buf[:n], test.data) {
			t.Errorf("test %d\nwant: %v\n got: %v\n", i, test.data, buf[:n])
		}
	}
	fmt.Println("All done reads")
}
Exemplo n.º 2
0
func main() {
	defer util.Run()()
	var handle *pcap.Handle
	var err error

	// Set up pcap packet capture
	if *fname != "" {
		log.Printf("Reading from pcap dump %q", *fname)
		handle, err = pcap.OpenOffline(*fname)
	} else {
		log.Printf("Starting capture on interface %q", *iface)
		handle, err = pcap.OpenLive(*iface, int32(*snaplen), true, pcap.BlockForever)
	}
	if err != nil {
		log.Fatal(err)
	}

	if err := handle.SetBPFFilter(*filter); err != nil {
		log.Fatal(err)
	}

	// Set up assembly
	streamFactory := &httpStreamFactory{}
	streamPool := tcpassembly.NewStreamPool(streamFactory)
	assembler := tcpassembly.NewAssembler(streamPool)

	log.Println("reading in packets")
	// Read in packets, pass to assembler.
	packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
	packets := packetSource.Packets()
	ticker := time.Tick(time.Minute)
	for {
		select {
		case packet := <-packets:
			// A nil packet indicates the end of a pcap file.
			if packet == nil {
				return
			}
			if *logAllPackets {
				log.Println(packet)
			}
			if packet.NetworkLayer() == nil || packet.TransportLayer() == nil || packet.TransportLayer().LayerType() != layers.LayerTypeTCP {
				log.Println("Unusable packet")
				continue
			}
			tcp := packet.TransportLayer().(*layers.TCP)
			assembler.AssembleWithTimestamp(packet.NetworkLayer().NetworkFlow(), tcp, packet.Metadata().Timestamp)

		case <-ticker:
			// Every minute, flush connections that haven't seen activity in the past 2 minutes.
			assembler.FlushOlderThan(time.Now().Add(time.Minute * -2))
		}
	}
}
Exemplo n.º 3
0
func main() {
	defer util.Run()()
	log.Printf("starting capture on interface %q", *iface)
	// Set up pcap packet capture
	handle, err := pcap.OpenLive(*iface, int32(*snaplen), true, pcap.BlockForever)
	if err != nil {
		panic(err)
	}
	if err := handle.SetBPFFilter(*filter); err != nil {
		panic(err)
	}

	// Set up assembly
	streamFactory := &myFactory{bidiMap: make(map[key]*bidi)}
	streamPool := tcpassembly.NewStreamPool(streamFactory)
	assembler := tcpassembly.NewAssembler(streamPool)

	log.Println("reading in packets")
	// Read in packets, pass to assembler.
	packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
	packets := packetSource.Packets()
	ticker := time.Tick(timeout / 4)
	for {
		select {
		case packet := <-packets:
			if *logAllPackets {
				log.Println(packet)
			}
			if packet.NetworkLayer() == nil || packet.TransportLayer() == nil || packet.TransportLayer().LayerType() != layers.LayerTypeTCP {
				log.Println("Unusable packet")
				continue
			}
			tcp := packet.TransportLayer().(*layers.TCP)
			assembler.AssembleWithTimestamp(packet.NetworkLayer().NetworkFlow(), tcp, packet.Metadata().Timestamp)

		case <-ticker:
			// Every minute, flush connections that haven't seen activity in the past minute.
			log.Println("---- FLUSHING ----")
			assembler.FlushOlderThan(time.Now().Add(-timeout))
			streamFactory.collectOldStreams()
		}
	}
}
Exemplo n.º 4
0
func benchmarkLayerDecode(source *BufferPacketSource, assemble bool) {
	var tcp layers.TCP
	var ip layers.IPv4
	var eth layers.Ethernet
	var udp layers.UDP
	var icmp layers.ICMPv4
	var payload gopacket.Payload
	parser := gopacket.NewDecodingLayerParser(
		layers.LayerTypeEthernet,
		&eth, &ip, &icmp, &tcp, &udp, &payload)
	pool := tcpassembly.NewStreamPool(&streamFactory{})
	assembler := tcpassembly.NewAssembler(pool)
	var decoded []gopacket.LayerType
	start := time.Now()
	packets, decodedlayers, assembled := 0, 0, 0
	for {
		packets++
		data, ci, err := source.ReadPacketData()
		if err == io.EOF {
			break
		} else if err != nil {
			fmt.Println("Error reading packet: ", err)
			continue
		}
		err = parser.DecodeLayers(data, &decoded)
		for _, typ := range decoded {
			decodedlayers++
			if typ == layers.LayerTypeTCP && assemble {
				assembled++
				assembler.AssembleWithTimestamp(ip.NetworkFlow(), &tcp, ci.Timestamp)
			}
		}
	}
	if assemble {
		assembler.FlushAll()
	}
	duration := time.Since(start)
	fmt.Printf("\tRead in %d packets in %v, decoded %v layers, assembled %v packets: %v per packet\n", packets, duration, decodedlayers, assembled, duration/time.Duration(packets))
}
Exemplo n.º 5
0
func main() {
	defer util.Run()()

	flushDuration, err := time.ParseDuration(*flushAfter)
	if err != nil {
		log.Fatal("invalid flush duration: ", *flushAfter)
	}

	log.Printf("starting capture on interface %q", *iface)
	// Set up pcap packet capture
	handle, err := pcap.OpenLive(*iface, int32(*snaplen), true, flushDuration/2)
	if err != nil {
		log.Fatal("error opening pcap handle: ", err)
	}
	if err := handle.SetBPFFilter(*filter); err != nil {
		log.Fatal("error setting BPF filter: ", err)
	}

	// Set up assembly
	streamFactory := &statsStreamFactory{}
	streamPool := tcpassembly.NewStreamPool(streamFactory)
	assembler := tcpassembly.NewAssembler(streamPool)
	assembler.MaxBufferedPagesPerConnection = *bufferedPerConnection
	assembler.MaxBufferedPagesTotal = *bufferedTotal

	log.Println("reading in packets")

	// We use a DecodingLayerParser here instead of a simpler PacketSource.
	// This approach should be measurably faster, but is also more rigid.
	// PacketSource will handle any known type of packet safely and easily,
	// but DecodingLayerParser will only handle those packet types we
	// specifically pass in.  This trade-off can be quite useful, though, in
	// high-throughput situations.
	var eth layers.Ethernet
	var dot1q layers.Dot1Q
	var ip4 layers.IPv4
	var ip6 layers.IPv6
	var ip6extensions layers.IPv6ExtensionSkipper
	var tcp layers.TCP
	var payload gopacket.Payload
	parser := gopacket.NewDecodingLayerParser(layers.LayerTypeEthernet,
		&eth, &dot1q, &ip4, &ip6, &ip6extensions, &tcp, &payload)
	decoded := make([]gopacket.LayerType, 0, 4)

	nextFlush := time.Now().Add(flushDuration / 2)

	var byteCount int64
	start := time.Now()

loop:
	for ; *packetCount != 0; *packetCount-- {
		// Check to see if we should flush the streams we have
		// that haven't seen any new data in a while.  Note we set a
		// timeout on our PCAP handle, so this should happen even if we
		// never see packet data.
		if time.Now().After(nextFlush) {
			stats, _ := handle.Stats()
			log.Printf("flushing all streams that haven't seen packets in the last 2 minutes, pcap stats: %+v", stats)
			assembler.FlushOlderThan(time.Now().Add(flushDuration))
			nextFlush = time.Now().Add(flushDuration / 2)
		}

		// To speed things up, we're also using the ZeroCopy method for
		// reading packet data.  This method is faster than the normal
		// ReadPacketData, but the returned bytes in 'data' are
		// invalidated by any subsequent ZeroCopyReadPacketData call.
		// Note that tcpassembly is entirely compatible with this packet
		// reading method.  This is another trade-off which might be
		// appropriate for high-throughput sniffing:  it avoids a packet
		// copy, but its cost is much more careful handling of the
		// resulting byte slice.
		data, ci, err := handle.ZeroCopyReadPacketData()

		if err != nil {
			log.Printf("error getting packet: %v", err)
			continue
		}
		err = parser.DecodeLayers(data, &decoded)
		if err != nil {
			log.Printf("error decoding packet: %v", err)
			continue
		}
		if *logAllPackets {
			log.Printf("decoded the following layers: %v", decoded)
		}
		byteCount += int64(len(data))
		// Find either the IPv4 or IPv6 address to use as our network
		// layer.
		foundNetLayer := false
		var netFlow gopacket.Flow
		for _, typ := range decoded {
			switch typ {
			case layers.LayerTypeIPv4:
				netFlow = ip4.NetworkFlow()
				foundNetLayer = true
			case layers.LayerTypeIPv6:
				netFlow = ip6.NetworkFlow()
				foundNetLayer = true
			case layers.LayerTypeTCP:
				if foundNetLayer {
					assembler.AssembleWithTimestamp(netFlow, &tcp, ci.Timestamp)
				} else {
					log.Println("could not find IPv4 or IPv6 layer, inoring")
				}
				continue loop
			}
		}
		log.Println("could not find TCP layer")
	}
	assembler.FlushAll()
	log.Printf("processed %d bytes in %v", byteCount, time.Since(start))
}