func main()

in main.go [185:251]
51 lines of code
20 McCabe index (conditional complexity)

func main() {
	defer util.Run()()
	var handle *pcap.Handle
	var err error

	flag.Parse()
	//labels validation
	if *fwdPerc > 100 || *fwdPerc < 0 {
		err = fmt.Errorf("Flag percentage is not between 0 and 100. Value: %f.", *fwdPerc)
	} else if *fwdBy != "" && *fwdBy != "header" && *fwdBy != "remoteaddr" {
		err = fmt.Errorf("Flag percentage-by (%s) is not valid.", *fwdBy)
	} else if *fwdBy == "header" && *fwdHeader == "" {
		err = fmt.Errorf("Flag percentage-by is set to header, but percentage-by-header is empty.")
	} else if *reqPort > 65535 || *reqPort < 0 {
		err = fmt.Errorf("Flag filter-request-port is not between 0 and 65535. Value: %f.", *fwdPerc)
	}
	if err != nil {
		log.Fatal(err)
	}

	// Set up pcap packet capture
	log.Printf("Starting capture on interface vxlan0")
	handle, err = pcap.OpenLive("vxlan0", 8951, true, pcap.BlockForever)
	if err != nil {
		log.Fatal(err)
	}

	// Set up BPF filter
	BPFFilter := fmt.Sprintf("%s%d", "tcp and dst port ", *reqPort)
	if err := handle.SetBPFFilter(BPFFilter); 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)

	//Open a TCP Client, for NLB Health Checks only
	go openTCPClient()

	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 || 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 1 minute.
			assembler.FlushOlderThan(time.Now().Add(time.Minute * -1))
		}
	}
}