Example #1
0
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
}
Example #2
0
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)
			}
		}
	}
	dumpcommand.Run(handle)
}