dns/ex/chaos/chaos.go
2012-08-24 12:42:41 +02:00

85 lines
2.0 KiB
Go

package main
// Print the version.bind and hostname.bind for each
// address of NAMESERVER
// (c) Miek Gieben - 2011
import (
"fmt"
"github.com/miekg/dns"
"os"
)
func main() {
if len(os.Args) != 2 {
fmt.Printf("%s NAMESERVER\n", os.Args[0])
os.Exit(1)
}
conf, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
m := new(dns.Msg)
m.Question = make([]dns.Question, 1)
c := new(dns.Client)
addr := addresses(conf, c, os.Args[1])
if len(addr) == 0 {
fmt.Printf("No address found for %s\n", os.Args[1])
os.Exit(1)
}
for _, a := range addr {
m.Question[0] = dns.Question{"version.bind.", dns.TypeTXT, dns.ClassCHAOS}
in, rtt, _ := c.ExchangeRtt(m, a)
if in != nil && len(in.Answer) > 0 {
fmt.Printf("(time %.3d µs) %v\n", rtt/1e3, in.Answer[0])
}
m.Question[0] = dns.Question{"hostname.bind.", dns.TypeTXT, dns.ClassCHAOS}
in, rtt, _ = c.ExchangeRtt(m, a)
if in != nil && len(in.Answer) > 0 {
fmt.Printf("(time %.3d µs) %v\n", rtt/1e3, in.Answer[0])
}
}
}
func qhandler(m, r *dns.Msg, e error, data interface{}) {
ips := make([]string, 0)
if r != nil && r.Rcode == dns.RcodeSuccess {
for _, aa := range r.Answer {
switch aa.(type) {
case *dns.RR_A:
ips = append(ips, aa.(*dns.RR_A).A.String()+":53")
case *dns.RR_AAAA:
ips = append(ips, "["+aa.(*dns.RR_AAAA).AAAA.String()+"]:53")
}
}
data.(chan []string) <- ips
return
}
data.(chan []string) <- nil
}
func addresses(conf *dns.ClientConfig, c *dns.Client, name string) []string {
m4 := new(dns.Msg)
m4.SetQuestion(dns.Fqdn(os.Args[1]), dns.TypeA)
m6 := new(dns.Msg)
m6.SetQuestion(dns.Fqdn(os.Args[1]), dns.TypeAAAA)
addr := make(chan []string)
defer close(addr)
c.Do(m4, conf.Servers[0]+":"+conf.Port, addr, qhandler)
c.Do(m6, conf.Servers[0]+":"+conf.Port, addr, qhandler)
var ips []string
i := 2 // two outstanding queries
forever:
for {
select {
case ip := <-addr:
ips = append(ips, ip...)
i--
if i == 0 {
break forever
}
}
}
return ips
}