Add peers from mDNS adverts, add separate config option

src/config/config.go

@@ -67,6 +67,7 @@ type NodeConfig struct {
 	Listen                      []string               `comment:"Listen addresses for incoming connections. You will need to add\nlisteners in order to accept incoming peerings from non-local nodes.\nMulticast peer discovery will work regardless of any listeners set\nhere. Each listener should be specified in URI format as above, e.g.\ntcp://0.0.0.0:0 or tcp://[::]:0 to listen on all interfaces."`
 	AdminListen                 string                 `comment:"Listen address for admin connections. Default is to listen for local\nconnections either on TCP/9001 or a UNIX socket depending on your\nplatform. Use this value for yggdrasilctl -endpoint=X. To disable\nthe admin socket, use the value \"none\" instead."`
 	MulticastInterfaces         []string               `comment:"Regular expressions for which interfaces multicast peer discovery\nshould be enabled on. If none specified, multicast peer discovery is\ndisabled. The default value is .* which uses all interfaces."`
+	MulticastDNSInterfaces      []string               `comment:"Regular expressions for which interfaces mDNS peer discovery\nshould be enabled on. If none specified, mDNS peer discovery is\ndisabled. The default value is .* which uses all interfaces."`
 	AllowedEncryptionPublicKeys []string               `comment:"List of peer encryption public keys to allow incoming TCP peering\nconnections from. If left empty/undefined then all connections will\nbe allowed by default. This does not affect outgoing peerings, nor\ndoes it affect link-local peers discovered via multicast."`
 	EncryptionPublicKey         string                 `comment:"Your public encryption key. Your peers may ask you for this to put\ninto their AllowedEncryptionPublicKeys configuration."`
 	EncryptionPrivateKey        string                 `comment:"Your private encryption key. DO NOT share this with anyone!"`
@@ -127,6 +128,7 @@ func GenerateConfig() *NodeConfig {
 	cfg.InterfacePeers = map[string][]string{}
 	cfg.AllowedEncryptionPublicKeys = []string{}
 	cfg.MulticastInterfaces = defaults.GetDefaults().DefaultMulticastInterfaces
+	cfg.MulticastDNSInterfaces = defaults.GetDefaults().DefaultMulticastDNSInterfaces
 	cfg.IfName = defaults.GetDefaults().DefaultIfName
 	cfg.IfMTU = defaults.GetDefaults().DefaultIfMTU
 	cfg.SessionFirewall.Enable = false

src/defaults/defaults.go

@@ -13,7 +13,8 @@ type platformDefaultParameters struct {
 	DefaultConfigFile string
 
 	// Multicast interfaces
-	DefaultMulticastInterfaces []string
+	DefaultMulticastInterfaces    []string
+	DefaultMulticastDNSInterfaces []string
 
 	// TUN/TAP
 	MaximumIfMTU  types.MTU

src/defaults/defaults_darwin.go

@@ -17,6 +17,10 @@ func GetDefaults() platformDefaultParameters {
 			"en.*",
 			"bridge.*",
 		},
+		DefaultMulticastDNSInterfaces: []string{
+			"en.*",
+			"bridge.*",
+		},
 
 		// TUN/TAP
 		MaximumIfMTU:  65535,

src/defaults/defaults_freebsd.go

@@ -16,6 +16,9 @@ func GetDefaults() platformDefaultParameters {
 		DefaultMulticastInterfaces: []string{
 			".*",
 		},
+		DefaultMulticastDNSInterfaces: []string{
+			".*",
+		},
 
 		// TUN/TAP
 		MaximumIfMTU:  32767,

src/defaults/defaults_linux.go

@@ -16,6 +16,9 @@ func GetDefaults() platformDefaultParameters {
 		DefaultMulticastInterfaces: []string{
 			".*",
 		},
+		DefaultMulticastDNSInterfaces: []string{
+			".*",
+		},
 
 		// TUN/TAP
 		MaximumIfMTU:  65535,

src/defaults/defaults_openbsd.go

@@ -16,6 +16,9 @@ func GetDefaults() platformDefaultParameters {
 		DefaultMulticastInterfaces: []string{
 			".*",
 		},
+		DefaultMulticastDNSInterfaces: []string{
+			".*",
+		},
 
 		// TUN/TAP
 		MaximumIfMTU:  16384,

src/defaults/defaults_other.go

@@ -16,6 +16,9 @@ func GetDefaults() platformDefaultParameters {
 		DefaultMulticastInterfaces: []string{
 			".*",
 		},
+		DefaultMulticastDNSInterfaces: []string{
+			".*",
+		},
 
 		// TUN/TAP
 		MaximumIfMTU:  65535,

src/defaults/defaults_windows.go

@@ -16,6 +16,9 @@ func GetDefaults() platformDefaultParameters {
 		DefaultMulticastInterfaces: []string{
 			".*",
 		},
+		DefaultMulticastDNSInterfaces: []string{
+			".*",
+		},
 
 		// TUN/TAP
 		MaximumIfMTU:  65535,

src/mdns/mdns.go

@@ -1,7 +1,6 @@
 package mdns
 
 import (
-	"context"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -11,7 +10,7 @@ import (
 
 	"github.com/Arceliar/phony"
 	"github.com/gologme/log"
-	"github.com/grandcat/zeroconf"
+	"github.com/neilalexander/mdns"
 
 	"github.com/yggdrasil-network/yggdrasil-go/src/admin"
 	"github.com/yggdrasil-network/yggdrasil-go/src/config"
@@ -25,23 +24,22 @@ const (
 
 type MDNS struct {
 	phony.Inbox
-	core      *yggdrasil.Core                   //
-	config    *config.NodeState                 //
-	log       *log.Logger                       //
-	info      []string                          //
-	instance  string                            //
-	_running  bool                              //
-	_exprs    []*regexp.Regexp                  //
-	_servers  map[string]map[string]*mDNSServer // intf -> ip -> *mDNSServer
-	_resolver *zeroconf.Resolver                //
-	_context  context.Context                   // used by _resolver
-	_cancel   context.CancelFunc                // used by _resolver
+	core     *yggdrasil.Core                   //
+	config   *config.NodeState                 //
+	log      *log.Logger                       //
+	info     []string                          //
+	instance string                            //
+	_running bool                              // is mDNS running?
+	_exprs   []*regexp.Regexp                  // mDNS interfaces
+	_servers map[string]map[string]*mDNSServer // intf -> ip -> *mDNSServer
 }
 
 type mDNSServer struct {
+	mdns     *MDNS
 	intf     net.Interface
-	server   *zeroconf.Server
+	server   *mdns.Server
 	listener *yggdrasil.TcpListener
+	stop     chan struct{}
 	time     time.Time
 }
 
@@ -62,20 +60,9 @@ func (m *MDNS) Init(core *yggdrasil.Core, state *config.NodeState, log *log.Logg
 	current := m.config.GetCurrent()
 	m._updateConfig(&current)
 
-	m._context, m._cancel = context.WithCancel(context.Background())
-	m._servers = make(map[string]map[string]*mDNSServer)
-
 	return nil
 }
 
-func (m *MDNS) listen(results <-chan *zeroconf.ServiceEntry) {
-	m.log.Info("Listening for other Yggdrasil nodes via mDNS")
-	for entry := range results {
-		log.Info("Received mDNS entry:", entry)
-	}
-	m.log.Info("No longer listening for other Yggdrasil nodes")
-}
-
 func (m *MDNS) Start() error {
 	var err error
 	phony.Block(m, func() {
@@ -86,25 +73,13 @@ func (m *MDNS) Start() error {
 }
 
 func (m *MDNS) _start() error {
-	var err error
 	if m._running {
 		return errors.New("mDNS module is already running")
 	}
 
-	resolver, err := zeroconf.NewResolver(nil)
-	if err != nil {
-		m.log.Fatalln("Failed to initialize resolver:", err.Error())
-	}
-	m._resolver = resolver
-	incoming := make(chan *zeroconf.ServiceEntry)
-	go m.listen(incoming)
-
-	err = m._resolver.Browse(m._context, MDNSService, MDNSDomain, incoming)
-	if err != nil {
-		m.log.Fatalln("Failed to browse:", err.Error())
-	}
-
+	m._servers = make(map[string]map[string]*mDNSServer)
 	m._running = true
+
 	m.Act(m, m._updateInterfaces)
 
 	return nil
@@ -120,7 +95,6 @@ func (m *MDNS) Stop() error {
 }
 
 func (m *MDNS) _stop() error {
-	m._cancel()
 	for _, intf := range m._servers {
 		for _, ip := range intf {
 			ip.server.Shutdown()
@@ -148,7 +122,7 @@ func (m *MDNS) _updateConfig(config *config.NodeConfig) error {
 	// allowed to use.
 	var exprs []*regexp.Regexp
 	// Compile each regular expression
-	for _, exstr := range config.MulticastInterfaces {
+	for _, exstr := range config.MulticastDNSInterfaces {
 		e, err := regexp.Compile(exstr)
 		if err != nil {
 			return err
@@ -230,7 +204,7 @@ func (m *MDNS) _updateInterfaces() {
 	}
 
 	// Work out which interfaces have disappeared.
-	for n, _ := range m._servers {
+	for n := range m._servers {
 		if addrs, ok := interfaces[n]; !ok {
 			for addr, server := range m._servers[n] {
 				if err := m._stopInterface(server.intf, addr); err != nil {
@@ -277,20 +251,28 @@ func (m *MDNS) _startInterface(intf net.Interface, addr string) error {
 		return fmt.Errorf("net.ResolveTCPAddr: %w", err)
 	}
 
-	// Register a proxy service. This allows us to specify the hostname and
-	// IP addresses to put into the DNS SRV record.
-	server, err := zeroconf.RegisterProxy(
-		m.instance,                    // instance name
-		MDNSService,                   // service name
-		MDNSDomain,                    // service domain
-		tcpaddr.Port,                  // TCP listener port
-		m.instance,                    // our hostname
-		[]string{tcpaddr.IP.String()}, // our IP address
-		m.info,                        // TXT record contents
-		[]net.Interface{intf},         // interfaces to use
+	// Create a zone.
+	hostname := fmt.Sprintf("%s.%s", m.instance, MDNSDomain)
+	zone, err := mdns.NewMDNSService(
+		m.instance,           // instance name
+		MDNSService,          // service name
+		MDNSDomain,           // service domain
+		hostname,             // our hostname
+		tcpaddr.Port,         // TCP listener port
+		[]net.IP{tcpaddr.IP}, // our IP address
+		m.info,               // TXT record contents
 	)
 	if err != nil {
-		return fmt.Errorf("zeroconf.RegisterProxy: %w", err)
+		return fmt.Errorf("mdns.NewMDNSService: %w", err)
+	}
+
+	// Create a server.
+	server, err := mdns.NewServer(&mdns.Config{
+		Zone:  zone,
+		Iface: &intf,
+	})
+	if err != nil {
+		return fmt.Errorf("mdns.NewServer: %w", err)
 	}
 
 	// Now store information about our new listener and server.
@@ -298,10 +280,13 @@ func (m *MDNS) _startInterface(intf net.Interface, addr string) error {
 		m._servers[intf.Name] = make(map[string]*mDNSServer)
 	}
 	m._servers[intf.Name][addr] = &mDNSServer{
+		mdns:     m,
 		intf:     intf,
+		stop:     make(chan struct{}),
 		server:   server,
 		listener: listener,
 	}
+	go m._servers[intf.Name][addr].listen()
 
 	return nil
 }
@@ -320,6 +305,7 @@ func (m *MDNS) _stopInterface(intf net.Interface, addr string) error {
 	}
 
 	// Shut down the mDNS server and the TCP listener.
+	close(server.stop)
 	server.server.Shutdown()
 	server.listener.Stop()
 
@@ -331,3 +317,30 @@ func (m *MDNS) _stopInterface(intf net.Interface, addr string) error {
 
 	return nil
 }
+
+func (s *mDNSServer) listen() {
+	s.mdns.log.Debugln("Started listening for mDNS on", s.intf.Name)
+	incoming := make(chan *mdns.ServiceEntry)
+
+	go func() {
+		if err := mdns.Listen(incoming, s.stop, &s.intf); err != nil {
+			s.mdns.log.Errorln("Failed to initialize resolver:", err.Error())
+		}
+	}()
+
+	for {
+		select {
+		case <-s.stop:
+			s.mdns.log.Debugln("Stopped listening for mDNS on", s.intf.Name)
+			break
+		case entry := <-incoming:
+			if entry.AddrV6.IP.IsLinkLocalUnicast() && entry.AddrV6.Zone == "" {
+				continue
+			}
+			addr := fmt.Sprintf("tcp://%s:%d", entry.AddrV6.IP, entry.Port)
+			if err := s.mdns.core.CallPeer(addr, entry.AddrV6.Zone); err != nil {
+				s.mdns.log.Warn("Failed to add peer from mDNS: ", err)
+			}
+		}
+	}
+}