// based on // https://github.com/akrennmair/gopcap/blob/master/tools/pcaptest/pcaptest.go package main import ( "flag" "fmt" "os" "github.com/akrennmair/gopcap" "github.com/op/go-logging" ) var log = logging.MustGetLogger("gpk") const ( TCP_FIN = 1 << iota TCP_SYN TCP_RST TCP_PSH TCP_ACK TCP_URG TCP_ECE TCP_CWR TCP_NS ) // it is dumb that go doesn't let me define additional methods // on the external package, now these have to be plain funcs func isRST(tcp *pcap.Tcphdr) bool { return (tcp.Flags & TCP_RST) != 0 } func isACK(tcp *pcap.Tcphdr) bool { return (tcp.Flags & TCP_ACK) != 0 } func isFIN(tcp *pcap.Tcphdr) bool { return (tcp.Flags & TCP_FIN) != 0 } func min(x uint32, y uint32) uint32 { if x < y { return x } return y } func usage() { fmt.Printf("usage: gopakketo [-d | -r ]\n") os.Exit(0) } var logFormat = logging.MustStringFormatter( `%{color}%{time:15:04:05.000} %{shortfunc} ▶ %{level:.4s} %{id:03x}%{color:reset} %{message}`, ) func main() { loggingBackend := logging.NewLogBackend(os.Stderr, "", 0) backendFormatter := logging.NewBackendFormatter(loggingBackend, logFormat) logging.SetBackend(backendFormatter) var device *string = flag.String("d", "", "device") var targetlist *string = flag.String("t", "", "target list e.g. 192.168.0.0/16 or 192.168.0-255.0-255") var portlist *string = flag.String("p", "", "port list e.g. 0-1024 or 22,23,80 or 0-1024,6667") //var outfile *string = flag.String("o", "", "output file") //var expr *string = flag.String("e", "", "filter expression") flag.Parse() go send(device, targetlist, portlist); receive(device); } func parsePortList (pl *[]uint16, s *string) { } func parseTargetList (tl *[]uint32, s *string) { } func send(device *string, targetlist *string, portlist *string) { pl := make([]uint16, 0) parsePortList(pl, portlist) tl := make([]uint32, 0) parseTargetList(tl, targetlist) } func sendSyn (device *string, sport uint16, dst uint32, dport uint16) { } func receive(device *string) { var pc *pcap.Pcap var err error ifs, err := pcap.Findalldevs() if len(ifs) == 0 { panic(fmt.Sprintf("no interfaces found : %s\n", err)) } if *device != "" { pc, err = pcap.Openlive(*device, 65535, true, 0) if pc == nil { log.Noticef("Openlive(%s) failed: %s\n", *device, err) return } if err != nil { log.Criticalf("Openlive(%s) failed: %s\n", *device, err) return } } else { usage() return } defer pc.Close() log.Infof("pcap version: %s\n", pcap.Version()) for pkt := pc.Next(); pkt != nil; pkt = pc.Next() { pkt.Decode() if pkt.TCP == nil { // we are only interested in TCP for scanning purposes rn continue } if !isRST(pkt.TCP) && !isACK(pkt.TCP) { // for scanning we only want RSTs (closed) and ACKs (open) continue } if isACK(pkt.TCP) { if isFIN(pkt.TCP) { continue } } fmt.Printf("%s\n", pkt.String()) } }