1// Copyright 2018 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5package osp 6 7// TODO(jophba): 8// - Make our own abstraction that has 9// .InstanceName, .HostName, .MetadataVersion, .FingerPrint 10// rather than using mdns.ServiceEntry 11// - Advertise TXT (text below) with "fp" and "mv" 12 13import ( 14 "context" 15 16 mdns "github.com/grandcat/zeroconf" 17) 18 19const ( 20 MdnsServiceType = "_openscreen._udp" 21 MdnsDomain = "local" 22) 23 24// Returns a channel of mDNS entries. The critical parts are 25// entry.Target (service name) entry.HostName, entry.AddrIPv4, and 26// entry.AddrIPv6. 27func BrowseMdns(ctx context.Context) (<-chan *mdns.ServiceEntry, error) { 28 entries := make(chan *mdns.ServiceEntry) 29 30 resolver, err := mdns.NewResolver(nil) 31 if err != nil { 32 return entries, err 33 } 34 35 err = resolver.Browse(ctx, MdnsServiceType, MdnsDomain, entries) 36 return entries, err 37} 38 39// Returns a channel of mDNS entries. The critical parts are, 40// entry.HostName, entry.AddrIPv4, and entry.AddrIPv6. 41func LookupMdns(ctx context.Context, target string) (<-chan *mdns.ServiceEntry, error) { 42 entries := make(chan *mdns.ServiceEntry) 43 44 resolver, err := mdns.NewResolver(nil) 45 if err != nil { 46 return entries, err 47 } 48 49 err = resolver.Lookup(ctx, target, MdnsServiceType, MdnsDomain, entries) 50 return entries, err 51} 52 53func RunMdnsServer(ctx context.Context, instance string, port int) error { 54 var text []string 55 server, err := mdns.Register(instance, MdnsServiceType, MdnsDomain, port, text, nil /* ifaces */) 56 if err != nil { 57 return err 58 } 59 waitUntilDone(ctx) 60 server.Shutdown() 61 return nil 62} 63