func handleDNSRequest(w dns.ResponseWriter, r *dns.Msg) {
if *debug {
Log.Printf("handleRequest: message: %+v\n", r)
}
m := new(dns.Msg)
m.SetReply(r)
m.Compress = false
switch r.Opcode {
case dns.OpcodeQuery:
parseQuery(m)
case dns.OpcodeUpdate:
for _, question := range r.Question {
for _, rr := range r.Ns {
updateRecord(rr, &question)
}
}
}
if r.IsTsig() != nil {
if w.TsigStatus() == nil {
m.SetTsig(r.Extra[len(r.Extra)-1].(*dns.TSIG).Hdr.Name,
dns.HmacMD5, 300, time.Now().Unix())
} else {
Log.Println("Status", w.TsigStatus().Error())
}
}
w.WriteMsg(m)
}
func formerr(w dns.ResponseWriter, req *dns.Msg) {
m := new(dns.Msg)
m.MsgHdr.Opcode = dns.OpcodeUpdate
if req.IsTsig() != nil {
m.SetTsig(userFromTsig(req), dns.HmacMD5, 300, time.Now().Unix())
}
w.WriteMsg(m.SetRcode(req, dns.RcodeFormatError))
}
func serverHandlerReturnSuccess(w dns.ResponseWriter, req *dns.Msg) {
m := new(dns.Msg)
m.SetReply(req)
if t := req.IsTsig(); t != nil {
if w.TsigStatus() == nil {
// Validated
m.SetTsig(rfc2136TestZone, dns.HmacMD5, 300, time.Now().Unix())
}
}
w.WriteMsg(m)
}
func serverHandlerReturnSuccess(w dns.ResponseWriter, req *dns.Msg) {
m := new(dns.Msg)
m.SetReply(req)
if req.Opcode == dns.OpcodeQuery && req.Question[0].Qtype == dns.TypeSOA && req.Question[0].Qclass == dns.ClassINET {
// Return SOA to appease findZoneByFqdn()
soaRR, _ := dns.NewRR(fmt.Sprintf("%s %d IN SOA ns1.%s admin.%s 2016022801 28800 7200 2419200 1200", rfc2136TestZone, rfc2136TestTTL, rfc2136TestZone, rfc2136TestZone))
m.Answer = []dns.RR{soaRR}
}
if t := req.IsTsig(); t != nil {
if w.TsigStatus() == nil {
// Validated
m.SetTsig(rfc2136TestZone, dns.HmacMD5, 300, time.Now().Unix())
}
}
w.WriteMsg(m)
}
func (d *DNSResponder) handleDNS(w dns.ResponseWriter, r *dns.Msg) {
var (
v4 bool
rr dns.RR
a net.IP
)
dom := r.Question[0].Name
m := new(dns.Msg)
m.SetReply(r)
if ip, ok := w.RemoteAddr().(*net.UDPAddr); ok {
a = ip.IP
v4 = a.To4() != nil
}
if ip, ok := w.RemoteAddr().(*net.TCPAddr); ok {
a = ip.IP
v4 = a.To4() != nil
}
if v4 {
rr = new(dns.A)
rr.(*dns.A).Hdr = dns.RR_Header{Name: dom, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 0}
rr.(*dns.A).A = a.To4()
} else {
rr = new(dns.AAAA)
rr.(*dns.AAAA).Hdr = dns.RR_Header{Name: dom, Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: 0}
rr.(*dns.AAAA).AAAA = a
}
switch r.Question[0].Qtype {
case dns.TypeAAAA, dns.TypeA:
m.Answer = append(m.Answer, rr)
}
if r.IsTsig() != nil {
if w.TsigStatus() == nil {
m.SetTsig(r.Extra[len(r.Extra)-1].(*dns.TSIG).Hdr.Name, dns.HmacMD5, 300, time.Now().Unix())
}
}
w.WriteMsg(m)
}
// base handler for dns server
func dnsHandler(w dns.ResponseWriter, request *dns.Msg) {
response := new(dns.Msg)
response.SetReply(request)
response.Compress = false
switch request.Opcode {
case dns.OpcodeQuery:
for _, q := range response.Question {
if readRR, e := getRecord(q.Name, q.Qtype); e == nil {
rr := readRR.(dns.RR)
if rr.Header().Name == q.Name {
response.Answer = append(response.Answer, rr)
}
}
}
case dns.OpcodeUpdate:
if request.IsTsig() != nil && w.TsigStatus() == nil {
for _, question := range request.Question {
for _, rr := range request.Ns {
updateRecord(rr, &question)
}
}
} else {
log.Println("droping update without tsig or with bad sig")
}
}
if request.IsTsig() != nil {
if w.TsigStatus() == nil {
response.SetTsig(request.Extra[len(request.Extra)-1].(*dns.TSIG).Hdr.Name, dns.HmacMD5, 300, time.Now().Unix())
} else {
log.Println("Status: ", w.TsigStatus().Error())
}
}
w.WriteMsg(response)
}
func handleReflect(w dns.ResponseWriter, r *dns.Msg) {
var (
v4 bool
rr dns.RR
str string
a net.IP
)
// TC must be done here
m := new(dns.Msg)
m.SetReply(r)
m.Compress = *compress
if ip, ok := w.RemoteAddr().(*net.UDPAddr); ok {
str = "Port: " + strconv.Itoa(ip.Port) + " (udp)"
a = ip.IP
v4 = a.To4() != nil
}
if ip, ok := w.RemoteAddr().(*net.TCPAddr); ok {
str = "Port: " + strconv.Itoa(ip.Port) + " (tcp)"
a = ip.IP
v4 = a.To4() != nil
}
if v4 {
rr = new(dns.RR_A)
rr.(*dns.RR_A).Hdr = dns.RR_Header{Name: dom, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 0}
rr.(*dns.RR_A).A = a.To4()
} else {
rr = new(dns.RR_AAAA)
rr.(*dns.RR_AAAA).Hdr = dns.RR_Header{Name: dom, Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: 0}
rr.(*dns.RR_AAAA).AAAA = a
}
t := new(dns.RR_TXT)
t.Hdr = dns.RR_Header{Name: dom, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 0}
t.Txt = []string{str}
switch r.Question[0].Qtype {
case dns.TypeAXFR:
c := make(chan *dns.XfrToken)
var e *error
if err := dns.XfrSend(w, r, c, e); err != nil {
close(c)
return
}
soa, _ := dns.NewRR(`whoami.miek.nl. IN SOA elektron.atoom.net. miekg.atoom.net. (
2009032802
21600
7200
604800
3600)`)
c <- &dns.XfrToken{RR: []dns.RR{soa, t, rr, soa}}
close(c)
w.Hijack()
// w.Close() // Client closes
return
case dns.TypeTXT:
m.Answer = append(m.Answer, t)
m.Extra = append(m.Extra, rr)
default:
fallthrough
case dns.TypeAAAA, dns.TypeA:
m.Answer = append(m.Answer, rr)
m.Extra = append(m.Extra, t)
}
if r.IsTsig() != nil {
if w.TsigStatus() == nil {
m.SetTsig(r.Extra[len(r.Extra)-1].(*dns.RR_TSIG).Hdr.Name, dns.HmacMD5, 300, time.Now().Unix())
} else {
println("Status", w.TsigStatus().Error())
}
}
if *printf {
fmt.Printf("%v\n", m.String())
}
w.Write(m)
}
// config stuff in Auth section (just as dynamic updates (*hint* *hint*)
// SUBSYSTEM. IN TXT "OPERATION<SPACE>OPTIONS..."
// ZONE. IN TXT "READ origin /z/bloep" - absolute path in fs
func config(w dns.ResponseWriter, req *dns.Msg, c *Config) {
logPrintf("config command")
if req.Question[0].Qclass != dns.ClassCHAOS {
logPrintf("non config command (wrong class)")
if z, ok := c.Zones[req.Question[0].Name]; ok {
serve(w, req, z)
return
}
formerr(w, req)
return
}
if req.IsTsig() == nil {
logPrintf("non config command (no tsig) - attemping metazone")
metazone(w, req, c)
return
}
if req.MsgHdr.Opcode != dns.OpcodeUpdate || req.Question[0].Qtype != dns.TypeSOA {
logPrintf("non config command (no update)")
formerr(w, req)
return
}
if e := w.TsigStatus(); e != nil {
logPrintf("non config command (tsig fail): %s", e.Error())
formerr(w, req)
return
}
// No need to check the user, if the tsig checks out, the user exists
logPrintf("config command ok")
for _, rr := range req.Ns {
t, ok := rr.(*dns.TXT)
if !ok {
formerr(w, req)
return
}
switch strings.ToUpper(t.Header().Name) {
case "ZONE.":
if e := configZONE(w, req, t, c); e != nil {
formerr(w, req)
return
}
case "USER.":
if userFromTsig(req) != dns.Fqdn(*superuser) {
logPrintf("user management is only for the superuser\n")
formerr(w, req)
return
}
if e := configUSER(w, req, t, c); e != nil {
formerr(w, req)
return
}
default:
formerr(w, req)
return
}
}
}
func handleReflect(w dns.ResponseWriter, r *dns.Msg) {
reflectHandled += 1
if reflectHandled%1000 == 0 {
fmt.Printf("Served %d reflections\n", reflectHandled)
}
var (
v4 bool
rr dns.RR
str string
a net.IP
)
m := new(dns.Msg)
m.SetReply(r)
m.Compress = *compress
if ip, ok := w.RemoteAddr().(*net.UDPAddr); ok {
str = "Port: " + strconv.Itoa(ip.Port) + " (udp)"
a = ip.IP
v4 = a.To4() != nil
}
if ip, ok := w.RemoteAddr().(*net.TCPAddr); ok {
str = "Port: " + strconv.Itoa(ip.Port) + " (tcp)"
a = ip.IP
v4 = a.To4() != nil
}
if v4 {
rr = new(dns.A)
rr.(*dns.A).Hdr = dns.RR_Header{Name: dom, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 0}
rr.(*dns.A).A = a.To4()
} else {
rr = new(dns.AAAA)
rr.(*dns.AAAA).Hdr = dns.RR_Header{Name: dom, Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: 0}
rr.(*dns.AAAA).AAAA = a
}
t := new(dns.TXT)
t.Hdr = dns.RR_Header{Name: dom, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 0}
t.Txt = []string{str}
switch r.Question[0].Qtype {
case dns.TypeTXT:
m.Answer = append(m.Answer, t)
m.Extra = append(m.Extra, rr)
default:
fallthrough
case dns.TypeAAAA, dns.TypeA:
m.Answer = append(m.Answer, rr)
m.Extra = append(m.Extra, t)
case dns.TypeAXFR, dns.TypeIXFR:
c := make(chan *dns.Envelope)
tr := new(dns.Transfer)
defer close(c)
err := tr.Out(w, r, c)
if err != nil {
return
}
soa, _ := dns.NewRR(`whoami.miek.nl. 0 IN SOA linode.atoom.net. miek.miek.nl. 2009032802 21600 7200 604800 3600`)
c <- &dns.Envelope{RR: []dns.RR{soa, t, rr, soa}}
w.Hijack()
// w.Close() // Client closes connection
return
}
if r.IsTsig() != nil {
if w.TsigStatus() == nil {
m.SetTsig(r.Extra[len(r.Extra)-1].(*dns.TSIG).Hdr.Name, dns.HmacMD5, 300, time.Now().Unix())
} else {
println("Status", w.TsigStatus().Error())
}
}
if *printf {
fmt.Printf("%v\n", m.String())
}
// set TC when question is tc.miek.nl.
if m.Question[0].Name == "tc.miek.nl." {
m.Truncated = true
// send half a message
buf, _ := m.Pack()
w.Write(buf[:len(buf)/2])
return
}
w.WriteMsg(m)
}