func ExamplePrivateHandle() {
dns.PrivateHandle("APAIR", TypeAPAIR, NewAPAIR)
defer dns.PrivateHandleRemove(TypeAPAIR)
rr, err := dns.NewRR("miek.nl. APAIR (1.2.3.4 1.2.3.5)")
if err != nil {
log.Fatal("could not parse APAIR record: ", err)
}
fmt.Println(rr)
// Output: miek.nl. 3600 IN APAIR 1.2.3.4 1.2.3.5
m := new(dns.Msg)
m.Id = 12345
m.SetQuestion("miek.nl.", TypeAPAIR)
m.Answer = append(m.Answer, rr)
fmt.Println(m)
// ;; opcode: QUERY, status: NOERROR, id: 12345
// ;; flags: rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
//
// ;; QUESTION SECTION:
// ;miek.nl. IN APAIR
//
// ;; ANSWER SECTION:
// miek.nl. 3600 IN APAIR 1.2.3.4 1.2.3.5
}
func setupRootZone() {
dns.HandleFunc(".", func(w dns.ResponseWriter, r *dns.Msg) {
m := new(dns.Msg)
m.SetRcode(r, dns.RcodeRefused)
w.WriteMsg(m)
})
}
func dorequest(c *C, msg *dns.Msg) *dns.Msg {
cli := new(dns.Client)
// cli.ReadTimeout = 2 * time.Second
r, _, err := cli.Exchange(msg, "127.0.0.1"+PORT)
if err != nil {
c.Logf("request err '%s': %s", msg.String(), err)
c.Fail()
}
return r
}
// Retrieve the MX records for miek.nl.
func ExampleMX() {
config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
c := new(dns.Client)
m := new(dns.Msg)
m.SetQuestion("miek.nl.", dns.TypeMX)
m.RecursionDesired = true
r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
if err != nil {
return
}
if r.Rcode != dns.RcodeSuccess {
return
}
for _, a := range r.Answer {
if mx, ok := a.(*dns.MX); ok {
fmt.Printf("%s\n", mx.String())
}
}
}
func exchangeSubnet(c *C, name string, dnstype uint16, ip string) *dns.Msg {
msg := new(dns.Msg)
msg.SetQuestion(name, dnstype)
o := new(dns.OPT)
o.Hdr.Name = "."
o.Hdr.Rrtype = dns.TypeOPT
e := new(dns.EDNS0_SUBNET)
e.Code = dns.EDNS0SUBNET
e.SourceScope = 0
e.Address = net.ParseIP(ip)
e.Family = 1 // IP4
e.SourceNetmask = net.IPv4len * 8
o.Option = append(o.Option, e)
msg.Extra = append(msg.Extra, o)
c.Log("msg", msg)
return dorequest(c, msg)
}
// Retrieve the DNSKEY records of a zone and convert them
// to DS records for SHA1, SHA256 and SHA384.
func ExampleDS(zone string) {
config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
c := new(dns.Client)
m := new(dns.Msg)
if zone == "" {
zone = "miek.nl"
}
m.SetQuestion(dns.Fqdn(zone), dns.TypeDNSKEY)
m.SetEdns0(4096, true)
r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
if err != nil {
return
}
if r.Rcode != dns.RcodeSuccess {
return
}
for _, k := range r.Answer {
if key, ok := k.(*dns.DNSKEY); ok {
for _, alg := range []uint8{dns.SHA1, dns.SHA256, dns.SHA384} {
fmt.Printf("%s; %d\n", key.ToDS(alg).String(), key.Flags)
}
}
}
}
func exchange(c *C, name string, dnstype uint16) *dns.Msg {
msg := new(dns.Msg)
msg.SetQuestion(name, dnstype)
return dorequest(c, msg)
}
func serve(w dns.ResponseWriter, req *dns.Msg, z *Zone) {
qtype := req.Question[0].Qtype
logPrintf("[zone %s] incoming %s %s %d from %s\n", z.Origin, req.Question[0].Name,
dns.TypeToString[qtype], req.MsgHdr.Id, w.RemoteAddr())
// Global meter
metrics.Get("queries").(metrics.Meter).Mark(1)
// Zone meter
z.Metrics.Queries.Mark(1)
logPrintln("Got request", req)
label := getQuestionName(z, req)
z.Metrics.LabelStats.Add(label)
realIp, _, _ := net.SplitHostPort(w.RemoteAddr().String())
z.Metrics.ClientStats.Add(realIp)
var ip net.IP // EDNS or real IP
var edns *dns.EDNS0_SUBNET
var opt_rr *dns.OPT
for _, extra := range req.Extra {
switch extra.(type) {
case *dns.OPT:
for _, o := range extra.(*dns.OPT).Option {
opt_rr = extra.(*dns.OPT)
switch e := o.(type) {
case *dns.EDNS0_NSID:
// do stuff with e.Nsid
case *dns.EDNS0_SUBNET:
z.Metrics.EdnsQueries.Mark(1)
logPrintln("Got edns", e.Address, e.Family, e.SourceNetmask, e.SourceScope)
if e.Address != nil {
edns = e
ip = e.Address
}
}
}
}
}
if len(ip) == 0 { // no edns subnet
ip = net.ParseIP(realIp)
}
targets, netmask := z.Options.Targeting.GetTargets(ip)
m := new(dns.Msg)
m.SetReply(req)
if e := m.IsEdns0(); e != nil {
m.SetEdns0(4096, e.Do())
}
m.Authoritative = true
// TODO: set scope to 0 if there are no alternate responses
if edns != nil {
if edns.Family != 0 {
if netmask < 16 {
netmask = 16
}
edns.SourceScope = uint8(netmask)
m.Extra = append(m.Extra, opt_rr)
}
}
labels, labelQtype := z.findLabels(label, targets, qTypes{dns.TypeMF, dns.TypeCNAME, qtype})
if labelQtype == 0 {
labelQtype = qtype
}
if labels == nil {
firstLabel := (strings.Split(label, "."))[0]
if firstLabel == "_status" {
if qtype == dns.TypeANY || qtype == dns.TypeTXT {
m.Answer = statusRR(label + "." + z.Origin + ".")
} else {
m.Ns = append(m.Ns, z.SoaRR())
}
m.Authoritative = true
w.WriteMsg(m)
return
}
if firstLabel == "_country" {
if qtype == dns.TypeANY || qtype == dns.TypeTXT {
h := dns.RR_Header{Ttl: 1, Class: dns.ClassINET, Rrtype: dns.TypeTXT}
h.Name = label + "." + z.Origin + "."
txt := []string{
w.RemoteAddr().String(),
ip.String(),
}
targets, netmask := z.Options.Targeting.GetTargets(ip)
txt = append(txt, strings.Join(targets, " "))
txt = append(txt, fmt.Sprintf("/%d", netmask), serverID, serverIP)
m.Answer = []dns.RR{&dns.TXT{Hdr: h,
Txt: txt,
}}
} else {
m.Ns = append(m.Ns, z.SoaRR())
}
m.Authoritative = true
w.WriteMsg(m)
return
}
// return NXDOMAIN
m.SetRcode(req, dns.RcodeNameError)
m.Authoritative = true
m.Ns = []dns.RR{z.SoaRR()}
w.WriteMsg(m)
return
}
if servers := labels.Picker(labelQtype, labels.MaxHosts); servers != nil {
var rrs []dns.RR
for _, record := range servers {
rr := record.RR
rr.Header().Name = req.Question[0].Name
rrs = append(rrs, rr)
}
m.Answer = rrs
}
if len(m.Answer) == 0 {
m.Ns = append(m.Ns, z.SoaRR())
}
logPrintln(m)
err := w.WriteMsg(m)
if err != nil {
// if Pack'ing fails the Write fails. Return SERVFAIL.
log.Println("Error writing packet", m)
dns.HandleFailed(w, req)
}
return
}
func serve(w dns.ResponseWriter, req *dns.Msg, z *Zone) {
qtype := req.Question[0].Qtype
logPrintf("[zone %s] incoming %s %s (id %d) from %s\n", z.Origin, req.Question[0].Name,
dns.TypeToString[qtype], req.Id, w.RemoteAddr())
// Global meter
metrics.Get("queries").(metrics.Meter).Mark(1)
// Zone meter
z.Metrics.Queries.Mark(1)
logPrintln("Got request", req)
label := getQuestionName(z, req)
z.Metrics.LabelStats.Add(label)
// IP that's talking to us (not EDNS CLIENT SUBNET)
var realIP net.IP
if addr, ok := w.RemoteAddr().(*net.UDPAddr); ok {
realIP = make(net.IP, len(addr.IP))
copy(realIP, addr.IP)
} else if addr, ok := w.RemoteAddr().(*net.TCPAddr); ok {
realIP = make(net.IP, len(addr.IP))
copy(realIP, addr.IP)
}
z.Metrics.ClientStats.Add(realIP.String())
var ip net.IP // EDNS or real IP
var edns *dns.EDNS0_SUBNET
var opt_rr *dns.OPT
for _, extra := range req.Extra {
switch extra.(type) {
case *dns.OPT:
for _, o := range extra.(*dns.OPT).Option {
opt_rr = extra.(*dns.OPT)
switch e := o.(type) {
case *dns.EDNS0_NSID:
// do stuff with e.Nsid
case *dns.EDNS0_SUBNET:
z.Metrics.EdnsQueries.Mark(1)
logPrintln("Got edns", e.Address, e.Family, e.SourceNetmask, e.SourceScope)
if e.Address != nil {
edns = e
ip = e.Address
}
}
}
}
}
if len(ip) == 0 { // no edns subnet
ip = realIP
}
targets, netmask := z.Options.Targeting.GetTargets(ip)
m := new(dns.Msg)
m.SetReply(req)
if e := m.IsEdns0(); e != nil {
m.SetEdns0(4096, e.Do())
}
m.Authoritative = true
// TODO: set scope to 0 if there are no alternate responses
if edns != nil {
if edns.Family != 0 {
if netmask < 16 {
netmask = 16
}
edns.SourceScope = uint8(netmask)
m.Extra = append(m.Extra, opt_rr)
}
}
labels, labelQtype := z.findLabels(label, targets, qTypes{dns.TypeMF, dns.TypeCNAME, qtype})
if labelQtype == 0 {
labelQtype = qtype
}
if labels == nil {
permitDebug := !*flagPrivateDebug || (realIP != nil && realIP.IsLoopback())
firstLabel := (strings.Split(label, "."))[0]
if permitDebug && firstLabel == "_status" {
if qtype == dns.TypeANY || qtype == dns.TypeTXT {
m.Answer = statusRR(label + "." + z.Origin + ".")
} else {
m.Ns = append(m.Ns, z.SoaRR())
}
m.Authoritative = true
w.WriteMsg(m)
t := time.Now()
logAccessPrintf("%s [%02d/%02d/%04d:%02d:%02d:%02d] %s %s %s\n", w.RemoteAddr(), t.Day(), t.Month(), t.Year(), t.Hour(), t.Minute(), t.Second(), req.Question[0].Name, dns.TypeToString[qtype], m.Answer)
return
}
if firstLabel == "_country" {
if qtype == dns.TypeANY || qtype == dns.TypeTXT {
h := dns.RR_Header{Ttl: 1, Class: dns.ClassINET, Rrtype: dns.TypeTXT}
h.Name = label + "." + z.Origin + "."
txt := []string{
w.RemoteAddr().String(),
ip.String(),
}
targets, netmask := z.Options.Targeting.GetTargets(ip)
txt = append(txt, strings.Join(targets, " "))
txt = append(txt, fmt.Sprintf("/%d", netmask), serverID, serverIP)
m.Answer = []dns.RR{&dns.TXT{Hdr: h,
Txt: txt,
}}
} else {
m.Ns = append(m.Ns, z.SoaRR())
}
m.Authoritative = true
w.WriteMsg(m)
t := time.Now()
logAccessPrintf("%s [%02d/%02d/%04d:%02d:%02d:%02d] %s %s %s\n", w.RemoteAddr(), t.Day(), t.Month(), t.Year(), t.Hour(), t.Minute(), t.Second(), req.Question[0].Name, dns.TypeToString[qtype], m.Answer)
return
}
// return NXDOMAIN
m.SetRcode(req, dns.RcodeNameError)
m.Authoritative = true
m.Ns = []dns.RR{z.SoaRR()}
w.WriteMsg(m)
t := time.Now()
logAccessPrintf("%s [%02d/%02d/%04d:%02d:%02d:%02d] %s %s %s\n", w.RemoteAddr(), t.Day(), t.Month(), t.Year(), t.Hour(), t.Minute(), t.Second(), req.Question[0].Name, dns.TypeToString[qtype], m.Answer)
return
}
if servers := labels.Picker(labelQtype, labels.MaxHosts); servers != nil {
var rrs []dns.RR
for _, record := range servers {
rr := dns.Copy(record.RR)
rr.Header().Name = req.Question[0].Name
rrs = append(rrs, rr)
}
m.Answer = rrs
}
if len(m.Answer) == 0 {
m.Ns = append(m.Ns, z.SoaRR())
} else {
if z.Labels[label] != nil {
z.Labels[label].Hits++
logPrintln("*********** ", z.Labels[label].Hits)
}
}
//logPrintln(m)
err := w.WriteMsg(m)
if err != nil {
// if Pack'ing fails the Write fails. Return SERVFAIL.
log.Println("Error writing packet", m)
dns.HandleFailed(w, req)
}
t := time.Now()
logAccessPrintf("%s [%02d/%02d/%04d:%02d:%02d:%02d] %s %s %s\n", w.RemoteAddr(), t.Day(), t.Month(), t.Year(), t.Hour(), t.Minute(), t.Second(), req.Question[0].Name, dns.TypeToString[qtype], m.Answer)
return
}