Requested unicast responses are never received

[brutella]

Unicast responses are not received when listing to the multicast link local address.

[daniel-sullivan]

Regarding this bug, I've managed to recreate it in an alternate way: when the Host for a given service is in the format x.x.local. as opposed to x.local., the parseHostname() function will fail to return any meaningful result thereby causing it to appear that the response hasn't been received. I believe this is the correct functionality from my reading of the RFC (https://datatracker.ietf.org/doc/html/rfc6762#section-3) but it could trip people up.

I created a test case browse_test.go which replicates this issue attached.

package dnssd_test

import (
	"context"
	"fmt"
	"github.com/brutella/dnssd"
	"net"
	"os"
	"strings"
	"testing"
	"time"
)

func TestBrowse(t *testing.T) {
	testIface, _ := net.InterfaceByName("lo0")
	if testIface == nil {
		testIface, _ = net.InterfaceByName("lo")
	}
	if testIface == nil {
		t.Fatal("can not find the local interface")
	}

	localhost, err := os.Hostname()
	if err != nil {
		t.Fatal(err)
	}
	localhost = strings.TrimSuffix(strings.Replace(localhost, " ", "-", -1), ".local") // replace spaces with dashes and remove .local suffix
	for tName, hostValue := range map[string]string{
		"regular host": "My-Computer",
		"empty host":   "",
		"ip address":   "192.168.0.1",
	} {
		t.Run(tName, func(t *testing.T) {
			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
			defer cancel()
			cfg := dnssd.Config{
				Name:   "My Service",
				Type:   "_hap._tcp",
				Host:   hostValue,
				Port:   12334,
				Ifaces: []string{testIface.Name},
			}
			srv, err := dnssd.NewService(cfg)
			if err != nil {
				t.Fatal(err)
			}
			rs, err := dnssd.NewResponder()
			if err != nil {
				t.Fatal(err)
			}

			go func() {
				_ = rs.Respond(ctx)
			}()

			_, err = rs.Add(srv)
			if err != nil {
				t.Fatal(err)

			}

			resultChan := make(chan dnssd.BrowseEntry)
			defer close(resultChan)
			go func() {
				_ = dnssd.LookupType(ctx, fmt.Sprintf("%s.local.", cfg.Type), func(entry dnssd.BrowseEntry) {
					resultChan <- entry
				}, func(entry dnssd.BrowseEntry) {})
			}()

			select {
			case <-ctx.Done():
				t.Fatal("timeout")
			case entry := <-resultChan:
				if entry.Name != cfg.Name {
					t.Fatalf("is=%v want=%v", entry.Name, cfg.Name)
				}
				if tName == "empty host" {
					if entry.Host != localhost {
						t.Fatalf("is=%v want=%v", entry.Host, localhost)
					}
				} else {
					if entry.Host != cfg.Host {
						t.Fatalf("is=%v want=%v", entry.Host, cfg.Host)
					}
				}
				if entry.Port != cfg.Port {
					t.Fatalf("is=%v want=%v", entry.Port, cfg.Port)
				}
			}
		})
	}
}

[brutella]

@daniel-sullivan Thanks for reporting. This is now fixed by 86afc0a