cleardns.go

package main

import (
	"github.com/miekg/dns"
	"log"
	"time"
)

var laddr = "127.0.0.1:5353"
var fakedns = "99.84.239.46:53"
var realdns = "8.8.8.8:53"
var safedns = "127.0.0.1:5300"
var timeout = 500*time.Millisecond

func main() {
	var err error
	err = dns.ListenAndServe(laddr, "udp", &maniacHandler{dns.Client{Timeout:timeout}})
	if err != nil {
		log.Fatal(err)
	}
}

type maniacHandler struct {
	client dns.Client
}

func (m *maniacHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
	answer, _, err := m.client.Exchange(r, fakedns)
	if err == nil {
		log.Print("Domain: "+r.Question[0].String()+" potentially polluted")
		answer, _, err = m.client.Exchange(r, safedns)
		if err != nil{
			log.Print(err)
			return
		}
		w.WriteMsg(answer)
		return
	}
	log.Print("Domain: "+r.Question[0].String()+" is safe")
	answer, _, err = m.client.Exchange(r, realdns)
	if err != nil{
		log.Print(err)
		return
	}
	w.WriteMsg(answer)
}