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 }
// Performs the actual query by service name (browse) or service instance name (lookup), // start response listeners goroutines and loops over the entries channel. func (c *client) query(params *LookupParams) error { var serviceName, serviceInstanceName string serviceName = fmt.Sprintf("%s.%s.", trimDot(params.Service), trimDot(params.Domain)) if params.Instance != "" { serviceInstanceName = fmt.Sprintf("%s.%s", params.Instance, serviceName) } // send the query m := new(dns.Msg) if serviceInstanceName != "" { m.Question = []dns.Question{ dns.Question{serviceInstanceName, dns.TypeSRV, dns.ClassINET}, dns.Question{serviceInstanceName, dns.TypeTXT, dns.ClassINET}, } m.RecursionDesired = false } else { m.SetQuestion(serviceName, dns.TypePTR) m.RecursionDesired = false } if err := c.sendQuery(m); err != nil { return err } return nil }
// Perform probing & announcement //TODO: implement a proper probing & conflict resolution func (s *server) probe() { q := new(dns.Msg) q.SetQuestion(s.service.ServiceInstanceName(), dns.TypePTR) q.RecursionDesired = false srv := &dns.SRV{ Hdr: dns.RR_Header{ Name: s.service.ServiceInstanceName(), Rrtype: dns.TypeSRV, Class: dns.ClassINET, Ttl: 3200, }, Priority: 0, Weight: 0, Port: uint16(s.service.Port), Target: s.service.HostName, } txt := &dns.TXT{ Hdr: dns.RR_Header{ Name: s.service.ServiceInstanceName(), Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 3200, }, Txt: s.service.Text, } q.Ns = []dns.RR{srv, txt} randomizer := rand.New(rand.NewSource(time.Now().UnixNano())) for i := 0; i < 3; i++ { if err := s.multicastResponse(q); err != nil { log.Println("[ERR] bonjour: failed to send probe:", err.Error()) } time.Sleep(time.Duration(randomizer.Intn(250)) * time.Millisecond) } resp := new(dns.Msg) resp.Answer = []dns.RR{} resp.Extra = []dns.RR{} s.composeLookupAnswers(resp, 3200) for i := 0; i < 3; i++ { if err := s.multicastResponse(resp); err != nil { log.Println("[ERR] bonjour: failed to send announcement:", err.Error()) } time.Sleep(2 * time.Second) } }
// 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()) } } }
// 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) } } } }