echodns updated

1 files changed, 21 insertions, 5 deletions

diff --git a/echodns.go b/echodns.go
index 64f1a3e..e5a3e4d 100644
--- a/echodns.go
+++ b/echodns.go
@@ -1,9 +1,12 @@
 package main

 

 import (

+	"bytes"

+	"encoding/binary"

 	_ "fmt"

 	"net"

 	"strings"

+	"time"

 

 	"github.com/google/gopacket"

 	"github.com/google/gopacket/layers"

@@ -12,20 +15,33 @@ import (
 func serveDNS(u *net.UDPConn, clientaddr net.Addr, request *layers.DNS) {

 	replyMess := request

 	var dnsAnswer layers.DNSResourceRecord

-	dnsAnswer.Type = layers.DNSTypeA

 	if request == nil || request.Questions == nil || len(request.Questions) == 0 {

 		return

 	} else {

 		dnsAnswer.Name = []byte(request.Questions[0].Name)

 	}

 	//fmt.Println(clientaddr.String())

-	dnsAnswer.Class = layers.DNSClassIN

 	replyMess.QR = true

 	replyMess.ANCount = 1

 	replyMess.OpCode = layers.DNSOpCodeQuery

 	replyMess.AA = true

-	dnsAnswer.IP = net.ParseIP(strings.Split(clientaddr.String(), ":")[0])

-	dnsAnswer.TTL = 1000

+	if request.Questions[0].Type == layers.DNSTypeA {

+		dnsAnswer.Type = layers.DNSTypeA

+		dnsAnswer.Class = layers.DNSClassIN

+		dnsAnswer.IP = net.ParseIP(strings.Split(clientaddr.String(), ":")[0])

+		dnsAnswer.TTL = 1000

+	} else if request.Questions[0].Type == layers.DNSTypeAAAA {

+		dnsAnswer.Type = layers.DNSTypeAAAA

+		dnsAnswer.Class = layers.DNSClassIN

+		t := time.Now().UnixMicro()

+		rdns_ipv4 := net.ParseIP(strings.Split(clientaddr.String(), ":")[0]).To4()

+		bytebuf := bytes.NewBuffer([]byte{})

+		binary.Write(bytebuf, binary.BigEndian, t)

+		binary.Write(bytebuf, binary.BigEndian, rdns_ipv4)

+		binary.Write(bytebuf, binary.BigEndian, []byte{0, 0, 0, 0})

+		dnsAnswer.IP = net.IP(bytebuf.Bytes())

+		dnsAnswer.TTL = 1000

+	}

 	replyMess.Answers = append(replyMess.Answers, dnsAnswer)

 	replyMess.ResponseCode = layers.DNSResponseCodeNoErr

 	buf := gopacket.NewSerializeBuffer()

@@ -40,7 +56,7 @@ func serveDNS(u *net.UDPConn, clientaddr net.Addr, request *layers.DNS) {
 func main() {

 	addr := net.UDPAddr{

 		Port: 53,

-		IP:   net.ParseIP("localhost.localdomain"),	//localhost

+		IP:   net.ParseIP("localhost.localdomain"), //localhost

 	}

 	u, _ := net.ListenUDP("udp", &addr)