// Get the key from the DNS (uses the local resolver) and return them.
// If nothing is found we return nil
func getKey(name string, keytag uint16, server string, tcp bool) *dns.DNSKEY {
c := new(dns.Client)
if tcp {
c.Net = "tcp"
}
m := new(dns.Msg)
m.SetQuestion(name, dns.TypeDNSKEY)
m.SetEdns0(4096, true)
r, _, err := c.Exchange(m, server)
if err != nil {
return nil
}
for _, k := range r.Answer {
if k1, ok := k.(*dns.DNSKEY); ok {
if k1.KeyTag() == keytag {
return k1
}
}
}
return nil
}
func addresses(conf *dns.ClientConfig, c *dns.Client, name string) (ips []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)
t := make(chan *dns.Msg)
defer close(t)
do(t, c, m4, net.JoinHostPort(conf.Servers[0], conf.Port))
do(t, c, m6, net.JoinHostPort(conf.Servers[0], conf.Port))
i := 2 // two outstanding queries
forever:
for {
select {
case d := <-t:
i--
if d == nil {
continue
}
if i == 0 {
break forever
}
if d.Rcode == dns.RcodeSuccess {
for _, a := range d.Answer {
switch a.(type) {
case *dns.A:
ips = append(ips,
net.JoinHostPort(a.(*dns.A).A.String(), "53"))
case *dns.AAAA:
ips = append(ips,
net.JoinHostPort(a.(*dns.AAAA).AAAA.String(), "53"))
}
}
}
}
}
return ips
}
