func (tap *Wiretap) capture(handle *pcap.Handle, channel chan gopacket.Packet) { defer handle.Close() src := gopacket.NewPacketSource(handle, handle.LinkType()) src.DecodeOptions = gopacket.NoCopy for { packet, err := src.NextPacket() if err == io.EOF { return } else if err == nil { channel <- packet } } }
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 }