func main() {
var (
pc *pcap.Pcap
err error
)
devloop:
for _, device := range []string{"bond0", "eth2", "en0", "any"} {
devs, errx := pcap.FindAllDevs()
if errx != "" {
log.Fatalf("%v", errx)
}
for _, dev := range devs {
if dev.Name == device {
pc, err = pcap.OpenLive(device, 8192, false, 1000)
if err == nil {
break devloop
}
}
}
}
if err != nil {
log.Fatalf("%v", err)
}
if err = pc.SetFilter("udp and dst port 53"); err != nil {
log.Fatalf("%v", err)
}
lock := &sync.Mutex{}
ss := &spacesaving.Rate{}
ss.Init(4096, 60*time.Second)
go Poller(lock, ss, pc)
for pkt, r := pc.NextEx(); r >= 0; pkt, r = pc.NextEx() {
if r == 0 {
continue
}
pkt.Decode()
var msg dns.Msg
if err := safeParse(&msg, pkt.Payload); err != nil {
fmt.Printf("err %v\n", err)
continue
}
qname := strings.ToLower(msg.Question[0].Name)
if len(qname) > 0 {
qname = qname[:len(qname)-1]
}
lock.Lock()
ss.Touch(qname, pkt.Time)
lock.Unlock()
}
fmt.Printf("Done\n")
}