func handleDnsRequest(w dns.ResponseWriter, req *dns.Msg) {
r := new(dns.Msg)
r.SetReply(req)
r.Authoritative = true
if len(req.Question) > 1 || req.Rcode != dns.OpcodeQuery {
r.SetRcode(req, dns.RcodeNotImplemented)
}
if len(req.Question) == 0 {
r.SetRcode(req, dns.RcodeFormatError)
}
if r.Rcode != dns.RcodeSuccess {
w.WriteMsg(r)
dnsReportChan <- 1
return
}
q := req.Question[0]
log.Debug("dns server: question=%v type=%v remote_host=%v", q.Name, q.Qtype, w.RemoteAddr())
switch q.Qtype {
case dns.TypeA:
h, _ := randomHost()
if h == "" || !isIPv4(h) {
if *f_randomhosts {
h = randomIPv4Addr()
} else {
// return NXDOMAIN
r.SetRcode(req, dns.RcodeNameError)
break
}
}
resp := new(dns.A)
resp.Hdr = dns.RR_Header{
Name: q.Name,
Rrtype: dns.TypeA,
Class: dns.ClassINET,
Ttl: ttl,
}
resp.A = net.ParseIP(h)
r.Answer = append(r.Answer, resp)
case dns.TypeAAAA:
h, _ := randomHost()
if h == "" || !isIPv6(h) {
if *f_randomhosts {
h = randomIPv6Addr()
} else {
// return NXDOMAIN
r.SetRcode(req, dns.RcodeNameError)
break
}
}
resp := new(dns.AAAA)
resp.Hdr = dns.RR_Header{
Name: q.Name,
Rrtype: dns.TypeAAAA,
Class: dns.ClassINET,
Ttl: ttl,
}
resp.AAAA = net.ParseIP(h)
r.Answer = append(r.Answer, resp)
case dns.TypeCNAME:
resp := new(dns.CNAME)
resp.Hdr = dns.RR_Header{
Name: q.Name,
Rrtype: dns.TypeCNAME,
Class: dns.ClassINET,
Ttl: ttl,
}
resp.Target = fmt.Sprintf("cname.%s", q.Name)
r.Answer = append(r.Answer, resp)
case dns.TypeMX:
resp := new(dns.MX)
resp.Hdr = dns.RR_Header{
Name: q.Name,
Rrtype: dns.TypeMX,
Class: dns.ClassINET,
Ttl: ttl,
}
resp.Mx = fmt.Sprintf("mx.%s", q.Name)
r.Answer = append(r.Answer, resp)
case dns.TypeSOA:
resp := new(dns.SOA)
resp.Hdr = dns.RR_Header{
Name: q.Name,
Rrtype: dns.TypeSOA,
Class: dns.ClassINET,
Ttl: ttl,
}
resp.Ns = fmt.Sprintf("ns.%s", q.Name)
resp.Mbox = fmt.Sprintf("admin-%s", q.Name)
r.Answer = append(r.Answer, resp)
}
w.WriteMsg(r)
dnsReportChan <- 1
}
