Adding zones with tests
This commit is contained in:
Armon Dadgar
parent
a26d5c2b94
commit
60a10ee1d7
198
zone.go
Normal file
198
zone.go
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package mdns
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import (
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"fmt"
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"github.com/miekg/dns"
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"net"
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"strings"
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)
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// Zone is the interface used to integrate with the server and
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// to serve records dynamically
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type Zone interface {
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Records(q dns.Question) []dns.RR
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}
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// MDNSService is used to export a named service by implementing a Zone
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type MDNSService struct {
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Instance string // Instance name (e.g. host name)
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Service string // Service name (e.g. _http._tcp.)
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Addr net.IP // Service IP
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Port int // Service Port
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Info string // Service info served as a TXT record
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Domain string // If blank, assumes ".local"
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serviceAddr string // Fully qualified service address
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instanceAddr string // Fully qualified instance address
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}
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// Init should be called to setup the internal state
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func (m *MDNSService) Init() error {
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// Setup default domain
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if m.Domain == "" {
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m.Domain = "local"
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}
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// Sanity check inputs
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if m.Instance == "" {
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return fmt.Errorf("Missing service instance name")
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}
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if m.Service == "" {
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return fmt.Errorf("Missing service name")
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}
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if m.Addr == nil {
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return fmt.Errorf("Missing service address")
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}
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if m.Port == 0 {
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return fmt.Errorf("Missing service port")
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}
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// Create the full addresses
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m.serviceAddr = fmt.Sprintf("%s.%s.",
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trimDot(m.Service), trimDot(m.Domain))
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m.instanceAddr = fmt.Sprintf("%s.%s",
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trimDot(m.Instance), m.serviceAddr)
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return nil
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}
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// trimDot is used to trim the dots from the start or end of a string
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func trimDot(s string) string {
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return strings.Trim(s, ".")
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}
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func (m *MDNSService) Records(q dns.Question) []dns.RR {
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switch q.Name {
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case m.serviceAddr:
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return m.serviceRecords(q)
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case m.instanceAddr:
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return m.instanceRecords(q)
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default:
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return nil
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}
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}
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// serviceRecords is called when the query matches the service name
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func (m *MDNSService) serviceRecords(q dns.Question) []dns.RR {
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switch q.Qtype {
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case dns.TypeANY:
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fallthrough
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case dns.TypePTR:
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// Build a PTR response for the service
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rr := &dns.PTR{
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Hdr: dns.RR_Header{
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Name: q.Name,
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Rrtype: dns.TypePTR,
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Class: dns.ClassINET,
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Ttl: 0,
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},
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Ptr: m.instanceAddr,
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}
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servRec := []dns.RR{rr}
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// Get the isntance records
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instRecs := m.instanceRecords(dns.Question{
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Name: m.instanceAddr,
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Qtype: dns.TypeANY,
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})
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// Return the service record with the instance records
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return append(servRec, instRecs...)
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default:
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return nil
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}
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}
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// serviceRecords is called when the query matches the instance name
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func (m *MDNSService) instanceRecords(q dns.Question) []dns.RR {
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switch q.Qtype {
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case dns.TypeANY:
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// Get the SRV, which includes A and AAAA
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recs := m.instanceRecords(dns.Question{
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Name: m.instanceAddr,
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Qtype: dns.TypeSRV,
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})
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// Add the TXT record
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recs = append(recs, m.instanceRecords(dns.Question{
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Name: m.instanceAddr,
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Qtype: dns.TypeTXT,
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})...)
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return recs
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case dns.TypeA:
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// Only handle if we have a ipv4 addr
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ipv4 := m.Addr.To4()
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if ipv4 == nil {
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return nil
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}
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a := &dns.A{
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Hdr: dns.RR_Header{
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Name: q.Name,
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Rrtype: dns.TypeA,
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Class: dns.ClassINET,
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Ttl: 0,
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},
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A: ipv4,
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}
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return []dns.RR{a}
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case dns.TypeAAAA:
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// Only handle if we have a ipv6 addr
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ipv6 := m.Addr.To16()
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if m.Addr.To4() != nil {
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return nil
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}
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a4 := &dns.AAAA{
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Hdr: dns.RR_Header{
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Name: q.Name,
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Rrtype: dns.TypeAAAA,
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Class: dns.ClassINET,
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Ttl: 0,
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},
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AAAA: ipv6,
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}
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return []dns.RR{a4}
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case dns.TypeSRV:
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// Create the SRV Record
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srv := &dns.SRV{
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Hdr: dns.RR_Header{
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Name: q.Name,
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Rrtype: dns.TypeSRV,
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Class: dns.ClassINET,
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Ttl: 0,
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},
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Priority: 10,
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Weight: 1,
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Port: uint16(m.Port),
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Target: q.Name,
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}
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recs := []dns.RR{srv}
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// Add the A record
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recs = append(recs, m.instanceRecords(dns.Question{
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Name: m.instanceAddr,
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Qtype: dns.TypeA,
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})...)
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// Add the AAAA record
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recs = append(recs, m.instanceRecords(dns.Question{
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Name: m.instanceAddr,
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Qtype: dns.TypeAAAA,
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})...)
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return recs
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case dns.TypeTXT:
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txt := &dns.TXT{
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Hdr: dns.RR_Header{
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Name: q.Name,
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Rrtype: dns.TypeTXT,
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Class: dns.ClassINET,
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Ttl: 0,
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},
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Txt: []string{m.Info},
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}
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return []dns.RR{txt}
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}
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return nil
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}
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183
zone_test.go
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183
zone_test.go
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@ -0,0 +1,183 @@
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package mdns
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import (
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"bytes"
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"github.com/miekg/dns"
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"reflect"
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"testing"
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)
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func makeService(t *testing.T) *MDNSService {
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m := &MDNSService{
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Instance: "hostname.",
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Service: "_http._tcp.",
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Addr: []byte{127, 0, 0, 1},
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Port: 80,
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Info: "Local web server",
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Domain: "local.",
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}
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if err := m.Init(); err != nil {
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t.Fatalf("err: %v", err)
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}
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return m
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}
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func TestMDNSService_BadAddr(t *testing.T) {
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s := makeService(t)
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q := dns.Question{
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Name: "random",
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Qtype: dns.TypeANY,
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}
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recs := s.Records(q)
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if len(recs) != 0 {
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t.Fatalf("bad: %v", recs)
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}
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}
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func TestMDNSService_ServiceAddr(t *testing.T) {
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s := makeService(t)
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q := dns.Question{
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Name: "_http._tcp.local.",
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Qtype: dns.TypeANY,
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}
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recs := s.Records(q)
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if len(recs) != 4 {
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t.Fatalf("bad: %v", recs)
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}
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ptr, ok := recs[0].(*dns.PTR)
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if !ok {
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t.Fatalf("bad: %v", recs[0])
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}
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if _, ok := recs[1].(*dns.SRV); !ok {
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t.Fatalf("bad: %v", recs[1])
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}
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if _, ok := recs[2].(*dns.A); !ok {
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t.Fatalf("bad: %v", recs[2])
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}
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if _, ok := recs[3].(*dns.TXT); !ok {
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t.Fatalf("bad: %v", recs[3])
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}
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if ptr.Ptr != s.instanceAddr {
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t.Fatalf("bad: %v", recs[0])
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}
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q.Qtype = dns.TypePTR
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recs2 := s.Records(q)
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if !reflect.DeepEqual(recs, recs2) {
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t.Fatalf("no match: %v %v", recs, recs2)
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}
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}
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func TestMDNSService_InstanceAddr_ANY(t *testing.T) {
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s := makeService(t)
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q := dns.Question{
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Name: "hostname._http._tcp.local.",
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Qtype: dns.TypeANY,
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}
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recs := s.Records(q)
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if len(recs) != 3 {
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t.Fatalf("bad: %v", recs)
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}
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if _, ok := recs[0].(*dns.SRV); !ok {
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t.Fatalf("bad: %v", recs[0])
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}
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if _, ok := recs[1].(*dns.A); !ok {
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t.Fatalf("bad: %v", recs[1])
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}
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if _, ok := recs[2].(*dns.TXT); !ok {
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t.Fatalf("bad: %v", recs[2])
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}
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}
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func TestMDNSService_InstanceAddr_SRV(t *testing.T) {
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s := makeService(t)
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q := dns.Question{
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Name: "hostname._http._tcp.local.",
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Qtype: dns.TypeSRV,
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}
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recs := s.Records(q)
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if len(recs) != 2 {
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t.Fatalf("bad: %v", recs)
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}
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srv, ok := recs[0].(*dns.SRV)
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if !ok {
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t.Fatalf("bad: %v", recs[0])
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}
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if _, ok := recs[1].(*dns.A); !ok {
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t.Fatalf("bad: %v", recs[1])
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}
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if srv.Target != s.instanceAddr {
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t.Fatalf("bad: %v", recs[0])
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}
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if srv.Port != uint16(s.Port) {
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t.Fatalf("bad: %v", recs[0])
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}
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}
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func TestMDNSService_InstanceAddr_A(t *testing.T) {
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s := makeService(t)
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q := dns.Question{
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Name: "hostname._http._tcp.local.",
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Qtype: dns.TypeA,
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}
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recs := s.Records(q)
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if len(recs) != 1 {
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t.Fatalf("bad: %v", recs)
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}
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a, ok := recs[0].(*dns.A)
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if !ok {
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t.Fatalf("bad: %v", recs[0])
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}
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if !bytes.Equal(a.A, s.Addr) {
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t.Fatalf("bad: %v", recs[0])
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}
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}
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func TestMDNSService_InstanceAddr_AAAA(t *testing.T) {
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s := makeService(t)
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s.Addr = []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
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11, 12, 13, 14, 15, 16}
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q := dns.Question{
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Name: "hostname._http._tcp.local.",
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Qtype: dns.TypeA,
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}
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recs := s.Records(q)
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if len(recs) != 0 {
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t.Fatalf("bad: %v", recs)
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}
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q.Qtype = dns.TypeAAAA
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recs = s.Records(q)
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if len(recs) != 1 {
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t.Fatalf("bad: %v", recs)
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}
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a4, ok := recs[0].(*dns.AAAA)
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if !ok {
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t.Fatalf("bad: %v", recs[0])
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}
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if !bytes.Equal(a4.AAAA, s.Addr) {
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t.Fatalf("bad: %v", recs[0])
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}
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}
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func TestMDNSService_InstanceAddr_TXT(t *testing.T) {
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s := makeService(t)
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q := dns.Question{
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Name: "hostname._http._tcp.local.",
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Qtype: dns.TypeTXT,
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}
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recs := s.Records(q)
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if len(recs) != 1 {
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t.Fatalf("bad: %v", recs)
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}
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txt, ok := recs[0].(*dns.TXT)
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if !ok {
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t.Fatalf("bad: %v", recs[0])
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}
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if txt.Txt[0] != s.Info {
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t.Fatalf("bad: %v", recs[0])
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}
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}
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