func main() {
flag.Parse()
var handle *pcap.Handle
var err error
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)
}
packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
for packet := range packetSource.Packets() {
if packet == nil {
return
}
if udpLayer := packet.Layer(layers.LayerTypeUDP); udpLayer != nil {
udp, _ := udpLayer.(*layers.UDP)
fwdSIPPacket(udp.BaseLayer.Payload)
}
}
}
//init re-initializes a snifer for uses
func (s *Snifer) init() error {
var handle *pcap.Handle
var err error
if s.conf.Offline {
handle, err = pcap.OpenOffline(s.source)
checkError(err, fmt.Sprintf("Create offline handle %s", s.source))
} else {
handle, err = pcap.OpenLive(s.source, s.conf.MaxPacket, s.conf.Promod, s.conf.Timeout)
checkError(err, fmt.Sprintf("Create Live handle %s", s.source))
if err == nil {
err = handle.SetBPFFilter(s.conf.Filter)
checkError(err, fmt.Sprintf("Setting BPFFilter %s: %s", s.source, s.conf.Filter))
}
}
if err != nil {
checkError(err, fmt.Sprintf("Creating Snifer for %s", s.source))
return err
}
s.handle = handle
log.Printf("Snifer: Handler created and ready!")
return nil
}
func getOpstream(cfg OpStreamSettings) (*packetHandlerContext, error) {
if cfg.PacketBufSize < 1 {
return nil, fmt.Errorf("invalid packet buffer size")
}
var pcapHandle *pcap.Handle
var err error
if len(cfg.PcapFile) > 0 {
pcapHandle, err = pcap.OpenOffline(cfg.PcapFile)
if err != nil {
return nil, fmt.Errorf("error opening pcap file: %v", err)
}
} else if len(cfg.NetworkInterface) > 0 {
pcapHandle, err = pcap.OpenLive(cfg.NetworkInterface, 32*1024*1024, false, pcap.BlockForever)
if err != nil {
return nil, fmt.Errorf("error listening to network interface: %v", err)
}
} else {
return nil, fmt.Errorf("must specify either a pcap file or network interface to record from")
}
if len(cfg.Expression) > 0 {
err = pcapHandle.SetBPFFilter(cfg.Expression)
if err != nil {
return nil, fmt.Errorf("error setting packet filter expression: %v", err)
}
}
h := NewPacketHandler(pcapHandle)
h.Verbose = userInfoLogger.isInVerbosity(DebugLow)
toolDebugLogger.Logvf(Info, "Created packet buffer size %d", cfg.PacketBufSize)
m := NewMongoOpStream(cfg.PacketBufSize)
return &packetHandlerContext{h, m, pcapHandle}, nil
}
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.Fatalln("Error: pcap file name is required!")
// 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("\npacket:")
// 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)
log.Printf("\n.......................................................\n")
log.Printf("packet:\n")
log.Printf("packet.Metadata().Timestamp=%T=%v=%v:\n%#v\n", packet.Metadata().Timestamp, packet.Metadata().Timestamp, packet.Metadata().Timestamp.UTC(), packet.Metadata().Timestamp)
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))
}
}
}
func setupPcap(device *string, port *string, rediscommand_ch chan<- redis_protocol.RedisCommand) {
var h *pcap.Handle
var err error
ifs, err_str := pcap.FindAllDevs()
if len(ifs) == 0 {
fmt.Printf("Warning: no devices found : %s\n", err_str)
}
h, err = pcap.OpenLive(*device, int32(65535), true, 1000)
if h == nil {
fmt.Printf("Openlive(%s) failed: %s\n", *device, err)
return
}
defer h.Close()
err = h.SetBPFFilter("dst port " + *port)
if err != nil {
fmt.Println("set filter failed")
return
}
packetSource := gopacket.NewPacketSource(h, h.LinkType())
for pkt := range packetSource.Packets() {
applicationLayer := pkt.ApplicationLayer()
if applicationLayer == nil {
continue
}
s := string(applicationLayer.Payload())
if s == "" {
continue
}
rediscommand, err := redis_protocol.Parse(s)
if err != nil {
fmt.Println(err)
continue
}
ipLayer := pkt.Layer(layers.LayerTypeIPv4)
if ipLayer != nil {
ip, _ := ipLayer.(*layers.IPv4)
rediscommand.Ipaddr = []byte(ip.SrcIP.String())
} else {
ipLayer := pkt.Layer(layers.LayerTypeIPv6)
if ipLayer != nil {
ip, _ := ipLayer.(*layers.IPv6)
rediscommand.Ipaddr = []byte(ip.SrcIP.String())
}
}
rediscommand_ch <- *rediscommand
}
}
func tryCapture(iface net.Interface) error {
if iface.Name[:2] == "lo" {
return fmt.Errorf("skipping loopback")
}
var h *pcap.Handle
var err error
switch *mode {
case "basic":
h, err = pcap.OpenLive(iface.Name, 65536, false, time.Second*3)
if err != nil {
return fmt.Errorf("openlive: %v", err)
}
defer h.Close()
case "filtered":
h, err = pcap.OpenLive(iface.Name, 65536, false, time.Second*3)
if err != nil {
return fmt.Errorf("openlive: %v", err)
}
defer h.Close()
if err := h.SetBPFFilter("port 80 or port 443"); err != nil {
return fmt.Errorf("setbpf: %v", err)
}
case "timestamp":
u, err := pcap.NewInactiveHandle(iface.Name)
if err != nil {
return err
}
defer u.CleanUp()
if err = u.SetSnapLen(65536); err != nil {
return err
} else if err = u.SetPromisc(false); err != nil {
return err
} else if err = u.SetTimeout(time.Second * 3); err != nil {
return err
}
sources := u.SupportedTimestamps()
if len(sources) == 0 {
return fmt.Errorf("no supported timestamp sources")
} else if err := u.SetTimestampSource(sources[0]); err != nil {
return fmt.Errorf("settimestampsource(%v): %v", sources[0], err)
} else if h, err = u.Activate(); err != nil {
return fmt.Errorf("could not activate: %v", err)
}
defer h.Close()
default:
panic("Invalid --mode: " + *mode)
}
go generatePackets()
h.ReadPacketData() // Do one dummy read to clear any timeouts.
data, ci, err := h.ReadPacketData()
if err != nil {
return fmt.Errorf("readpacketdata: %v", err)
}
log.Printf("Read packet, %v bytes, CI: %+v", len(data), ci)
return nil
}
func main() {
defer util.Run()()
var handle *pcap.Handle
var err error
signal.Notify(sigs, syscall.SIGHUP)
go startWebServer()
go sighandler()
flag.Parse()
go printDebugInfo()
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(true); 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())
}
}
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)
}
}
}
for {
process(handle)
}
}
// set packet capture filter, by ip and port
func setDeviceFilter(handle *pcap.Handle, filterIP string, filterPort uint16) {
var bpfFilter = "tcp"
if filterPort != 0 {
bpfFilter += " port " + strconv.Itoa(int(filterPort))
}
if filterIP != "" {
bpfFilter += " ip host " + filterIP
}
var err = handle.SetBPFFilter(bpfFilter)
if err != nil {
fmt.Fprintln(os.Stderr, "Set capture filter failed, ", err)
}
}
func main() {
flag.Parse()
filter := strings.Join(flag.Args(), " ")
if device == NO_DEVICE && offlineFile == NO_OFFLINE_FILE {
flag.Usage()
os.Exit(1)
}
var (
handle *pcap.Handle
err error
)
if hasFile(offlineFile) {
fmt.Printf("Reading packet from %s:\n", offlineFile)
handle, err = pcap.OpenOffline(offlineFile)
} else {
fmt.Printf("Reading packet from %s:\n", device)
handle, err = pcap.OpenLive(
device,
PACKET_SAMPLE_SIZE,
true,
pcap.BlockForever,
)
}
if err != nil {
panic(err)
}
fmt.Printf("Applying filter: %s\n", filter)
if err = handle.SetBPFFilter(filter); err != nil {
panic(err)
}
for {
packet, ci, err := handle.ReadPacketData()
if err == io.EOF {
break
}
if err != nil {
panic(err)
}
go handlePacket(packet, ci)
}
}
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())
}
}
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)
}
}
}
// https://github.com/google/gopacket/blob/master/dumpcommand/tcpdump.go
dumpcommand.Run(handle)
}
//setup a device or pcap file for capture, returns a handle
func initHandle(config *pdnsConfig) *pcap.Handle {
var handle *pcap.Handle
var err error
if config.device != "" && !config.pfring {
handle, err = pcap.OpenLive(config.device, 65536, true, pcap.BlockForever)
if err != nil {
log.Debug(err)
return nil
}
/* } else if dev != "" && pfring {
handle, err = pfring.NewRing(dev, 65536, true, pfring.FlagPromisc)
if err != nil {
log.Debug(err)
return nil
}
*/
} else if config.pcapFile != "" {
handle, err = pcap.OpenOffline(config.pcapFile)
if err != nil {
log.Debug(err)
return nil
}
} else {
log.Debug("You must specify either a capture device or a pcap file")
return nil
}
err = handle.SetBPFFilter(config.bpf)
if err != nil {
log.Debug(err)
return nil
}
/* if dev != "" && pfring {
handle.Enable()
}
*/
return handle
}
func doReadPacket(handle *pcap.Handle) {
var err error
handle.SetBPFFilter(filter)
if err != nil {
log.Fatal(err)
}
for {
data, ci, err := handle.ReadPacketData()
switch {
case err == io.EOF:
return
case err != nil:
log.Println(err)
default:
packet := gopacket.NewPacket(data, layers.LayerTypeEthernet, gopacket.NoCopy)
incomePacket := incomePacket{packet: packet, ci: &ci}
switchPacket(incomePacket)
}
}
}
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!`
// Set up buffer and options for serialization.
buf := gopacket.NewSerializeBuffer()
opts := gopacket.SerializeOptions{
FixLengths: true,
ComputeChecksums: true,
}
if err := gopacket.SerializeLayers(buf, opts, ð, &ipv4, &tcp, gopacket.Payload([]byte(data))); err != nil {
fmt.Println(err)
}
if err := handle.WritePacketData(buf.Bytes()); err != nil {
fmt.Println(err)
}
fmt.Println("I sent Response-hijack packet!")
}
}
// dumpcommand.Run(handle)
}
func main() {
defer util.Run()()
var handle *pcap.Handle
var err error
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)
// }
// Set up pcap packet capture
if *fname != "" {
log.Printf("Reading from pcap dump %q", *fname)
handle, err = pcap.OpenOffline(*fname)
} else {
log.Fatalln("Error: pcap file name is required!")
// 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("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,
ð, &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)
break loop // 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))
}
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.Fatalln("Error: pcap file name is required!")
// log.Printf("Starting capture on interface %q", *iface)
// handle, err = pcap.OpenLive(*iface, int32(*snaplen), true, pcap.BlockForever)
}
// 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)
ReadingPackets:
for {
select {
case packet := <-packets:
if *logAllPackets {
log.Println(packet)
}
if packet == nil {
log.Println("Unusable packet: if packet == nil")
break ReadingPackets
}
if packet.NetworkLayer() == nil {
log.Println("Unusable packet: if packet.NetworkLayer() == nil")
break ReadingPackets
}
if packet.TransportLayer() == nil {
log.Println("Unusable packet: if packet.TransportLayer() == nil")
break ReadingPackets
}
if packet.TransportLayer().LayerType() != layers.LayerTypeTCP {
log.Println("Unusable packet: if packet.TransportLayer().LayerType() != layers.LayerTypeTCP")
break ReadingPackets
}
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()
}
}
}
func main() {
var handle *pcap.Handle
var err error
flag.Parse()
if *fname != "" {
log.Printf("Reading from pcap file %q", *fname)
handle, err = pcap.OpenOffline(*fname)
} else {
log.Printf("Starting capture on interface %q", *iface)
handle, err = pcap.OpenLive(*iface, int32(*snaplen), false, pcap.BlockForever)
}
if err != nil {
log.Fatal(err)
}
if *filter == "" {
// from kcs_const.js
*filter = "tcp port 80 and host"
*filter += " (125.6.184.15 or 125.6.184.16 or 125.6.187.205 or"
*filter += " 125.6.187.229 or 125.6.187.253 or 125.6.188.25 or"
*filter += " 125.6.189.7 or 125.6.189.39 or 125.6.189.71 or"
*filter += " 125.6.189.103 or 125.6.189.135 or 125.6.189.167 or"
*filter += " 125.6.189.215 or 125.6.189.247 or 203.104.209.7 or"
*filter += " 203.104.209.23 or 203.104.209.39 or 203.104.209.55 or"
*filter += " 203.104.209.71 or 203.104.209.102 or 203.104.248.135)"
}
if err := handle.SetBPFFilter(*filter); err != nil {
log.Fatal(err)
}
// Set up assembly
streamFactory := &httpStreamFactory{}
streamPool := tcpassembly.NewStreamPool(streamFactory)
assembler := tcpassembly.NewAssembler(streamPool)
// Set up paser goroutine
cpus := runtime.NumCPU()
runtime.GOMAXPROCS(cpus)
wait := new(sync.WaitGroup)
go parse(wait)
// 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 packet.NetworkLayer() == nil || packet.TransportLayer() == nil {
continue
}
if packet.TransportLayer().LayerType() != layers.LayerTypeTCP {
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))
}
}
parserCh <- Res{port: 0}
wait.Wait()
}
func getOpstream(cfg OpStreamSettings) (*packetHandlerContext, error) {
if cfg.PacketBufSize < 1 {
return nil, fmt.Errorf("invalid packet buffer size")
}
var pcapHandle *pcap.Handle
var err error
if len(cfg.PcapFile) > 0 {
pcapHandle, err = pcap.OpenOffline(cfg.PcapFile)
if err != nil {
return nil, fmt.Errorf("error opening pcap file: %v", err)
}
} else if len(cfg.NetworkInterface) > 0 {
inactive, err := pcap.NewInactiveHandle(cfg.NetworkInterface)
if err != nil {
return nil, fmt.Errorf("error creating a pcap handle: %v", err)
}
// This is safe; calling `Activate()` steals the underlying ptr.
defer inactive.CleanUp()
err = inactive.SetSnapLen(64 * 1024)
if err != nil {
return nil, fmt.Errorf("error setting snaplen on pcap handle: %v", err)
}
err = inactive.SetPromisc(false)
if err != nil {
return nil, fmt.Errorf("error setting promisc on pcap handle: %v", err)
}
err = inactive.SetTimeout(pcap.BlockForever)
if err != nil {
return nil, fmt.Errorf("error setting timeout on pcap handle: %v", err)
}
// CaptureBufSize is in KiB to match units on `tcpdump -B`.
err = inactive.SetBufferSize(cfg.CaptureBufSize * 1024)
if err != nil {
return nil, fmt.Errorf("error setting buffer size on pcap handle: %v", err)
}
pcapHandle, err = inactive.Activate()
if err != nil {
return nil, fmt.Errorf("error listening to network interface: %v", err)
}
} else {
return nil, fmt.Errorf("must specify either a pcap file or network interface to record from")
}
if len(cfg.Expression) > 0 {
err = pcapHandle.SetBPFFilter(cfg.Expression)
if err != nil {
return nil, fmt.Errorf("error setting packet filter expression: %v", err)
}
}
h := NewPacketHandler(pcapHandle)
h.Verbose = userInfoLogger.isInVerbosity(DebugLow)
toolDebugLogger.Logvf(Info, "Created packet buffer size %d", cfg.PacketBufSize)
m := NewMongoOpStream(cfg.PacketBufSize)
return &packetHandlerContext{h, m, pcapHandle}, nil
}