Merge pull request #1026 from micro/tun

Network & Tunnel refactor

client/rpc_client.go

@@ -316,6 +316,22 @@ func (r *rpcClient) Options() Options {
 	return r.opts
 }
 
+// hasProxy checks if we have proxy set in the environment
+func (r *rpcClient) hasProxy() bool {
+	// get proxy
+	if prx := os.Getenv("MICRO_PROXY"); len(prx) > 0 {
+		return true
+	}
+
+	// get proxy address
+	if prx := os.Getenv("MICRO_PROXY_ADDRESS"); len(prx) > 0 {
+		return true
+	}
+
+	return false
+}
+
+// next returns an iterator for the next nodes to call
 func (r *rpcClient) next(request Request, opts CallOptions) (selector.Next, error) {
 	service := request.Service()
 
@@ -431,10 +447,18 @@ func (r *rpcClient) Call(ctx context.Context, request Request, response interfac
 		return err
 	}
 
-	ch := make(chan error, callOpts.Retries+1)
+	// get the retries
+	retries := callOpts.Retries
+
+	// disable retries when using a proxy
+	if r.hasProxy() {
+		retries = 0
+	}
+
+	ch := make(chan error, retries+1)
 	var gerr error
 
-	for i := 0; i <= callOpts.Retries; i++ {
+	for i := 0; i <= retries; i++ {
 		go func(i int) {
 			ch <- call(i)
 		}(i)
@@ -514,10 +538,18 @@ func (r *rpcClient) Stream(ctx context.Context, request Request, opts ...CallOpt
 		err    error
 	}
 
-	ch := make(chan response, callOpts.Retries+1)
+	// get the retries
+	retries := callOpts.Retries
+
+	// disable retries when using a proxy
+	if r.hasProxy() {
+		retries = 0
+	}
+
+	ch := make(chan response, retries+1)
 	var grr error
 
-	for i := 0; i <= callOpts.Retries; i++ {
+	for i := 0; i <= retries; i++ {
 		go func(i int) {
 			s, err := call(i)
 			ch <- response{s, err}

client/rpc_codec.go

@@ -88,32 +88,24 @@ func (rwc *readWriteCloser) Close() error {
 }
 
 func getHeaders(m *codec.Message) {
-	get := func(hdr string) string {
+	set := func(v, hdr string) string {
-		if hd := m.Header[hdr]; len(hd) > 0 {
+		if len(v) > 0 {
-			return hd
+			return v
 		}
-		// old
+		return m.Header[hdr]
-		return m.Header["X-"+hdr]
 	}
 
 	// check error in header
-	if len(m.Error) == 0 {
+	m.Error = set(m.Error, "Micro-Error")
-		m.Error = get("Micro-Error")
-	}
 
 	// check endpoint in header
-	if len(m.Endpoint) == 0 {
+	m.Endpoint = set(m.Endpoint, "Micro-Endpoint")
-		m.Endpoint = get("Micro-Endpoint")
-	}
 
 	// check method in header
-	if len(m.Method) == 0 {
+	m.Method = set(m.Method, "Micro-Method")
-		m.Method = get("Micro-Method")
-	}
 
-	if len(m.Id) == 0 {
+	// set the request id
-		m.Id = get("Micro-Id")
+	m.Id = set(m.Id, "Micro-Id")
-	}
 }
 
 func setHeaders(m *codec.Message, stream string) {
@@ -122,7 +114,6 @@ func setHeaders(m *codec.Message, stream string) {
 			return
 		}
 		m.Header[hdr] = v
-		m.Header["X-"+hdr] = v
 	}
 
 	set("Micro-Id", m.Id)

network/network.go

@@ -6,8 +6,6 @@ import (
 
 	"github.com/micro/go-micro/client"
 	"github.com/micro/go-micro/server"
-	"github.com/micro/go-micro/transport"
-	"github.com/micro/go-micro/tunnel"
 )
 
 var (
@@ -56,14 +54,6 @@ type Network interface {
 	Server() server.Server
 }
 
-// message is network message
-type message struct {
-	// msg is transport message
-	msg *transport.Message
-	// session is tunnel session
-	session tunnel.Session
-}
-
 // NewNetwork returns a new network interface
 func NewNetwork(opts ...Option) Network {
 	return newNetwork(opts...)

network/node.go

@@ -216,7 +216,7 @@ func (n *node) DeletePeerNode(id string) error {
 
 // PruneStalePeerNodes prune the peers that have not been seen for longer than given time
 // It returns a map of the the nodes that got pruned
-func (n *node) PruneStalePeerNodes(pruneTime time.Duration) map[string]*node {
+func (n *node) PruneStalePeers(pruneTime time.Duration) map[string]*node {
 	n.Lock()
 	defer n.Unlock()
 

network/node_test.go

@@ -225,7 +225,7 @@ func TestPruneStalePeerNodes(t *testing.T) {
 	time.Sleep(pruneTime)
 
 	// should delete all nodes besides node
-	pruned := node.PruneStalePeerNodes(pruneTime)
+	pruned := node.PruneStalePeers(pruneTime)
 
 	if len(pruned) != len(nodes)-1 {
 		t.Errorf("Expected pruned node count: %d, got: %d", len(nodes)-1, len(pruned))

network/options.go

@@ -22,8 +22,8 @@ type Options struct {
 	Address string
 	// Advertise sets the address to advertise
 	Advertise string
-	// Peers is a list of peers to connect to
+	// Nodes is a list of nodes to connect to
-	Peers []string
+	Nodes []string
 	// Tunnel is network tunnel
 	Tunnel tunnel.Tunnel
 	// Router is network router
@@ -62,10 +62,10 @@ func Advertise(a string) Option {
 	}
 }
 
-// Peers is a list of peers to connect to
+// Nodes is a list of nodes to connect to
-func Peers(n ...string) Option {
+func Nodes(n ...string) Option {
 	return func(o *Options) {
-		o.Peers = n
+		o.Nodes = n
 	}
 }
 

network/resolver/dns/dns.go

@@ -31,6 +31,17 @@ func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
 		r.Address = "1.0.0.1:53"
 	}
 
+	//nolint:prealloc
+	var records []*resolver.Record
+
+	// parsed an actual ip
+	if v := net.ParseIP(host); v != nil {
+		records = append(records, &resolver.Record{
+			Address: net.JoinHostPort(host, port),
+		})
+		return records, nil
+	}
+
 	m := new(dns.Msg)
 	m.SetQuestion(dns.Fqdn(host), dns.TypeA)
 	rec, err := dns.ExchangeContext(context.Background(), m, r.Address)
@@ -38,9 +49,6 @@ func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
 		return nil, err
 	}
 
-	//nolint:prealloc
-	var records []*resolver.Record
-
 	for _, answer := range rec.Answer {
 		h := answer.Header()
 		// check record type matches
@@ -59,5 +67,12 @@ func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
 		})
 	}
 
+	// no records returned so just best effort it
+	if len(records) == 0 {
+		records = append(records, &resolver.Record{
+			Address: net.JoinHostPort(host, port),
+		})
+	}
+
 	return records, nil
 }

network/service/handler/handler.go

@@ -55,7 +55,7 @@ func (n *Network) Connect(ctx context.Context, req *pbNet.ConnectRequest, resp *
 	}
 
 	// get list of existing nodes
-	nodes := n.Network.Options().Peers
+	nodes := n.Network.Options().Nodes
 
 	// generate a node map
 	nodeMap := make(map[string]bool)
@@ -84,7 +84,7 @@ func (n *Network) Connect(ctx context.Context, req *pbNet.ConnectRequest, resp *
 
 	// reinitialise the peers
 	n.Network.Init(
-		network.Peers(nodes...),
+		network.Nodes(nodes...),
 	)
 
 	// call the connect method

proxy/mucp/mucp.go

@@ -83,7 +83,8 @@ func readLoop(r server.Request, s client.Stream) error {
 
 // toNodes returns a list of node addresses from given routes
 func toNodes(routes []router.Route) []string {
-	nodes := make([]string, len(routes))
+	nodes := make([]string, 0, len(routes))
+
 	for _, node := range routes {
 		address := node.Address
 		if len(node.Gateway) > 0 {
@@ -91,11 +92,13 @@ func toNodes(routes []router.Route) []string {
 		}
 		nodes = append(nodes, address)
 	}
+
 	return nodes
 }
 
 func toSlice(r map[uint64]router.Route) []router.Route {
 	routes := make([]router.Route, 0, len(r))
+
 	for _, v := range r {
 		routes = append(routes, v)
 	}
@@ -161,6 +164,8 @@ func (p *Proxy) filterRoutes(ctx context.Context, routes []router.Route) []route
 		filteredRoutes = append(filteredRoutes, route)
 	}
 
+	log.Tracef("Proxy filtered routes %+v\n", filteredRoutes)
+
 	return filteredRoutes
 }
 
@@ -225,13 +230,15 @@ func (p *Proxy) cacheRoutes(service string) ([]router.Route, error) {
 // refreshMetrics will refresh any metrics for our local cached routes.
 // we may not receive new watch events for these as they change.
 func (p *Proxy) refreshMetrics() {
-	services := make([]string, 0, len(p.Routes))
-
 	// get a list of services to update
 	p.RLock()
+
+	services := make([]string, 0, len(p.Routes))
+
 	for service := range p.Routes {
 		services = append(services, service)
 	}
+
 	p.RUnlock()
 
 	// get and cache the routes for the service
@@ -246,6 +253,8 @@ func (p *Proxy) manageRoutes(route router.Route, action string) error {
 	p.Lock()
 	defer p.Unlock()
 
+	log.Tracef("Proxy taking route action %v %+v\n", action, route)
+
 	switch action {
 	case "create", "update":
 		if _, ok := p.Routes[route.Service]; !ok {
@@ -253,7 +262,12 @@ func (p *Proxy) manageRoutes(route router.Route, action string) error {
 		}
 		p.Routes[route.Service][route.Hash()] = route
 	case "delete":
+		// delete that specific route
 		delete(p.Routes[route.Service], route.Hash())
+		// clean up the cache entirely
+		if len(p.Routes[route.Service]) == 0 {
+			delete(p.Routes, route.Service)
+		}
 	default:
 		return fmt.Errorf("unknown action: %s", action)
 	}
@@ -288,7 +302,7 @@ func (p *Proxy) ProcessMessage(ctx context.Context, msg server.Message) error {
 	// TODO: check that we're not broadcast storming by sending to the same topic
 	// that we're actually subscribed to
 
-	log.Tracef("Received message for %s", msg.Topic())
+	log.Tracef("Proxy received message for %s", msg.Topic())
 
 	var errors []string
 
@@ -329,7 +343,7 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 		return errors.BadRequest("go.micro.proxy", "service name is blank")
 	}
 
-	log.Tracef("Received request for %s", service)
+	log.Tracef("Proxy received request for %s", service)
 
 	// are we network routing or local routing
 	if len(p.Links) == 0 {
@@ -363,15 +377,17 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 	}
 
 	//nolint:prealloc
-	var opts []client.CallOption
+	opts := []client.CallOption{
-
 		// set strategy to round robin
-	opts = append(opts, client.WithSelectOption(selector.WithStrategy(selector.RoundRobin)))
+		client.WithSelectOption(selector.WithStrategy(selector.RoundRobin)),
+	}
 
 	// if the address is already set just serve it
 	// TODO: figure it out if we should know to pick a link
 	if len(addresses) > 0 {
-		opts = append(opts, client.WithAddress(addresses...))
+		opts = append(opts,
+			client.WithAddress(addresses...),
+		)
 
 		// serve the normal way
 		return p.serveRequest(ctx, p.Client, service, endpoint, req, rsp, opts...)
@@ -387,10 +403,16 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 			opts = append(opts, client.WithAddress(addresses...))
 		}
 
+		log.Tracef("Proxy calling %+v\n", addresses)
 		// serve the normal way
 		return p.serveRequest(ctx, p.Client, service, endpoint, req, rsp, opts...)
 	}
 
+	// we're assuming we need routes to operate on
+	if len(routes) == 0 {
+		return errors.InternalServerError("go.micro.proxy", "route not found")
+	}
+
 	var gerr error
 
 	// we're routing globally with multiple links
@@ -404,11 +426,16 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 			continue
 		}
 
-		log.Debugf("Proxy using route %+v\n", route)
+		log.Tracef("Proxy using route %+v\n", route)
 
 		// set the address to call
 		addresses := toNodes([]router.Route{route})
-		opts = append(opts, client.WithAddress(addresses...))
+		// set the address in the options
+		// disable retries since its one route processing
+		opts = append(opts,
+			client.WithAddress(addresses...),
+			client.WithRetries(0),
+		)
 
 		// do the request with the link
 		gerr = p.serveRequest(ctx, link, service, endpoint, req, rsp, opts...)
@@ -558,7 +585,9 @@ func NewProxy(opts ...options.Option) proxy.Proxy {
 	}()
 
 	go func() {
-		t := time.NewTicker(time.Minute)
+		// TODO: speed up refreshing of metrics
+		// without this ticking effort e.g stream
+		t := time.NewTicker(time.Second * 10)
 		defer t.Stop()
 
 		// we must refresh route metrics since they do not trigger new events

router/default.go

@@ -799,7 +799,8 @@ func (r *router) flushRouteEvents(evType EventType) ([]*Event, error) {
 
 	// build a list of events to advertise
 	events := make([]*Event, len(bestRoutes))
-	i := 0
+	var i int
+
 	for _, route := range bestRoutes {
 		event := &Event{
 			Type:      evType,
@@ -823,9 +824,10 @@ func (r *router) Solicit() error {
 
 	// advertise the routes
 	r.advertWg.Add(1)
+
 	go func() {
-		defer r.advertWg.Done()
+		r.publishAdvert(Solicitation, events)
-		r.publishAdvert(RouteUpdate, events)
+		r.advertWg.Done()
 	}()
 
 	return nil

router/router.go

@@ -111,6 +111,8 @@ const (
 	Announce AdvertType = iota
 	// RouteUpdate advertises route updates
 	RouteUpdate
+	// Solicitation indicates routes were solicited
+	Solicitation
 )
 
 // String returns human readable advertisement type
@@ -120,6 +122,8 @@ func (t AdvertType) String() string {
 		return "announce"
 	case RouteUpdate:
 		return "update"
+	case Solicitation:
+		return "solicitation"
 	default:
 		return "unknown"
 	}

server/rpc_codec.go

@@ -86,24 +86,18 @@ func getHeader(hdr string, md map[string]string) string {
 }
 
 func getHeaders(m *codec.Message) {
-	get := func(hdr, v string) string {
+	set := func(v, hdr string) string {
 		if len(v) > 0 {
 			return v
 		}
-
+		return m.Header[hdr]
-		if hd := m.Header[hdr]; len(hd) > 0 {
-			return hd
 	}
 
-		// old
+	m.Id = set(m.Id, "Micro-Id")
-		return m.Header["X-"+hdr]
+	m.Error = set(m.Error, "Micro-Error")
-	}
+	m.Endpoint = set(m.Endpoint, "Micro-Endpoint")
-
+	m.Method = set(m.Method, "Micro-Method")
-	m.Id = get("Micro-Id", m.Id)
+	m.Target = set(m.Target, "Micro-Service")
-	m.Error = get("Micro-Error", m.Error)
-	m.Endpoint = get("Micro-Endpoint", m.Endpoint)
-	m.Method = get("Micro-Method", m.Method)
-	m.Target = get("Micro-Service", m.Target)
 
 	// TODO: remove this cruft
 	if len(m.Endpoint) == 0 {
@@ -321,7 +315,6 @@ func (c *rpcCodec) Write(r *codec.Message, b interface{}) error {
 
 		// write an error if it failed
 		m.Error = errors.Wrapf(err, "Unable to encode body").Error()
-		m.Header["X-Micro-Error"] = m.Error
 		m.Header["Micro-Error"] = m.Error
 		// no body to write
 		if err := c.codec.Write(m, nil); err != nil {

server/rpc_server.go

@@ -549,6 +549,7 @@ func (s *rpcServer) Register() error {
 	node.Metadata["protocol"] = "mucp"
 
 	s.RLock()
+
 	// Maps are ordered randomly, sort the keys for consistency
 	var handlerList []string
 	for n, e := range s.handlers {
@@ -557,6 +558,7 @@ func (s *rpcServer) Register() error {
 			handlerList = append(handlerList, n)
 		}
 	}
+
 	sort.Strings(handlerList)
 
 	var subscriberList []Subscriber
@@ -566,18 +568,20 @@ func (s *rpcServer) Register() error {
 			subscriberList = append(subscriberList, e)
 		}
 	}
+
 	sort.Slice(subscriberList, func(i, j int) bool {
 		return subscriberList[i].Topic() > subscriberList[j].Topic()
 	})
 
 	endpoints := make([]*registry.Endpoint, 0, len(handlerList)+len(subscriberList))
+
 	for _, n := range handlerList {
 		endpoints = append(endpoints, s.handlers[n].Endpoints()...)
 	}
+
 	for _, e := range subscriberList {
 		endpoints = append(endpoints, e.Endpoints()...)
 	}
-	s.RUnlock()
 
 	service := &registry.Service{
 		Name:      config.Name,
@@ -586,9 +590,10 @@ func (s *rpcServer) Register() error {
 		Endpoints: endpoints,
 	}
 
-	s.Lock()
+	// get registered value
 	registered := s.registered
-	s.Unlock()
+
+	s.RUnlock()
 
 	if !registered {
 		log.Logf("Registry [%s] Registering node: %s", config.Registry.String(), node.Id)
@@ -610,6 +615,8 @@ func (s *rpcServer) Register() error {
 	defer s.Unlock()
 
 	s.registered = true
+	// set what we're advertising
+	s.opts.Advertise = addr
 
 	// subscribe to the topic with own name
 	sub, err := s.opts.Broker.Subscribe(config.Name, s.HandleEvent)

service.go

@@ -9,9 +9,9 @@ import (
 
 	"github.com/micro/go-micro/client"
 	"github.com/micro/go-micro/config/cmd"
-	"github.com/micro/go-micro/debug/service/handler"
 	"github.com/micro/go-micro/debug/profile"
 	"github.com/micro/go-micro/debug/profile/pprof"
+	"github.com/micro/go-micro/debug/service/handler"
 	"github.com/micro/go-micro/plugin"
 	"github.com/micro/go-micro/server"
 	"github.com/micro/go-micro/util/log"

tunnel/default.go

@@ -127,7 +127,6 @@ func (t *tun) newSession(channel, sessionId string) (*session, bool) {
 		closed:  make(chan bool),
 		recv:    make(chan *message, 128),
 		send:    t.send,
-		wait:    make(chan bool),
 		errChan: make(chan error, 1),
 	}
 
@@ -198,8 +197,8 @@ func (t *tun) announce(channel, session string, link *link) {
 	}
 }
 
-// monitor monitors outbound links and attempts to reconnect to the failed ones
+// manage monitors outbound links and attempts to reconnect to the failed ones
-func (t *tun) monitor() {
+func (t *tun) manage() {
 	reconnect := time.NewTicker(ReconnectTime)
 	defer reconnect.Stop()
 
@@ -208,9 +207,48 @@ func (t *tun) monitor() {
 		case <-t.closed:
 			return
 		case <-reconnect.C:
+			t.manageLinks()
+		}
+	}
+}
+
+// manageLink sends channel discover requests periodically and
+// keepalive messages to link
+func (t *tun) manageLink(link *link) {
+	keepalive := time.NewTicker(KeepAliveTime)
+	defer keepalive.Stop()
+	discover := time.NewTicker(DiscoverTime)
+	defer discover.Stop()
+
+	for {
+		select {
+		case <-t.closed:
+			return
+		case <-link.closed:
+			return
+		case <-discover.C:
+			// send a discovery message to all links
+			if err := t.sendMsg("discover", link); err != nil {
+				log.Debugf("Tunnel failed to send discover to link %s: %v", link.Remote(), err)
+			}
+		case <-keepalive.C:
+			// send keepalive message
+			log.Debugf("Tunnel sending keepalive to link: %v", link.Remote())
+			if err := t.sendMsg("keepalive", link); err != nil {
+				log.Debugf("Tunnel error sending keepalive to link %v: %v", link.Remote(), err)
+				t.delLink(link.Remote())
+				return
+			}
+		}
+	}
+}
+
+// manageLinks is a function that can be called to immediately to link setup
+func (t *tun) manageLinks() {
+	var delLinks []string
+
 	t.RLock()
 
-			var delLinks []string
 	// check the link status and purge dead links
 	for node, link := range t.links {
 		// check link status
@@ -242,27 +280,46 @@ func (t *tun) monitor() {
 
 	// build list of unknown nodes to connect to
 	t.RLock()
+
 	for _, node := range t.options.Nodes {
 		if _, ok := t.links[node]; !ok {
 			connect = append(connect, node)
 		}
 	}
+
 	t.RUnlock()
 
+	var wg sync.WaitGroup
+
 	for _, node := range connect {
+		wg.Add(1)
+
+		go func(node string) {
+			defer wg.Done()
+
 			// create new link
 			link, err := t.setupLink(node)
 			if err != nil {
 				log.Debugf("Tunnel failed to setup node link to %s: %v", node, err)
-					continue
+				return
 			}
+
 			// save the link
 			t.Lock()
+			defer t.Unlock()
+
+			// just check nothing else was setup in the interim
+			if _, ok := t.links[node]; ok {
+				link.Close()
+				return
+			}
+			// save the link
 			t.links[node] = link
-				t.Unlock()
+		}(node)
-			}
-		}
 	}
+
+	// wait for all threads to finish
+	wg.Wait()
 }
 
 // process outgoing messages sent by all local sessions
@@ -328,6 +385,7 @@ func (t *tun) process() {
 				// and the message is being sent outbound via
 				// a dialled connection don't use this link
 				if loopback && msg.outbound {
+					log.Tracef("Link for node %s is loopback", node)
 					err = errors.New("link is loopback")
 					continue
 				}
@@ -335,6 +393,7 @@ func (t *tun) process() {
 				// if the message was being returned by the loopback listener
 				// send it back up the loopback link only
 				if msg.loopback && !loopback {
+					log.Tracef("Link for message %s is loopback", node)
 					err = errors.New("link is not loopback")
 					continue
 				}
@@ -364,7 +423,7 @@ func (t *tun) process() {
 			// send the message
 			for _, link := range sendTo {
 				// send the message via the current link
-				log.Tracef("Sending %+v to %s", newMsg.Header, link.Remote())
+				log.Tracef("Tunnel sending %+v to %s", newMsg.Header, link.Remote())
 
 				if errr := link.Send(newMsg); errr != nil {
 					log.Debugf("Tunnel error sending %+v to %s: %v", newMsg.Header, link.Remote(), errr)
@@ -470,6 +529,9 @@ func (t *tun) listen(link *link) {
 			return
 		}
 
+		// this state machine block handles the only message types
+		// that we know or care about; connect, close, open, accept,
+		// discover, announce, session, keepalive
 		switch mtype {
 		case "connect":
 			log.Debugf("Tunnel link %s received connect message", link.Remote())
@@ -495,14 +557,14 @@ func (t *tun) listen(link *link) {
 			t.links[link.Remote()] = link
 			t.Unlock()
 
-			// send back a discovery
+			// send back an announcement of our channels discovery
 			go t.announce("", "", link)
+			// ask for the things on the other wise
+			go t.sendMsg("discover", link)
 			// nothing more to do
 			continue
 		case "close":
-			// TODO: handle the close message
+			log.Debugf("Tunnel link %s received close message", link.Remote())
-			// maybe report io.EOF or kill the link
-
 			// if there is no channel then we close the link
 			// as its a signal from the other side to close the connection
 			if len(channel) == 0 {
@@ -521,6 +583,8 @@ func (t *tun) listen(link *link) {
 			// try get the dialing socket
 			s, exists := t.getSession(channel, sessionId)
 			if exists && !loopback {
+				// only delete the session if its unicast
+				// otherwise ignore close on the multicast
 				if s.mode == Unicast {
 					// only delete this if its unicast
 					// but not if its a loopback conn
@@ -541,20 +605,24 @@ func (t *tun) listen(link *link) {
 		// an accept returned by the listener
 		case "accept":
 			s, exists := t.getSession(channel, sessionId)
-			// we don't need this
+			// just set accepted on anything not unicast
 			if exists && s.mode > Unicast {
 				s.accepted = true
 				continue
 			}
+			// if its already accepted move on
 			if exists && s.accepted {
 				continue
 			}
+			// otherwise we're going to process to accept
 		// a continued session
 		case "session":
 			// process message
-			log.Tracef("Received %+v from %s", msg.Header, link.Remote())
+			log.Tracef("Tunnel received %+v from %s", msg.Header, link.Remote())
 		// an announcement of a channel listener
 		case "announce":
+			log.Tracef("Tunnel received %+v from %s", msg.Header, link.Remote())
+
 			// process the announcement
 			channels := strings.Split(channel, ",")
 
@@ -562,7 +630,10 @@ func (t *tun) listen(link *link) {
 			link.setChannel(channels...)
 
 			// this was an announcement not intended for anything
-			if sessionId == "listener" || sessionId == "" {
+			// if the dialing side sent "discover" then a session
+			// id would be present. We skip in case of multicast.
+			switch sessionId {
+			case "listener", "multicast", "":
 				continue
 			}
 
@@ -574,14 +645,19 @@ func (t *tun) listen(link *link) {
 					continue
 				}
 
-				// send the announce back to the caller
+				msg := &message{
-				s.recv <- &message{
 					typ:     "announce",
 					tunnel:  id,
 					channel: channel,
 					session: sessionId,
 					link:    link.id,
 				}
+
+				// send the announce back to the caller
+				select {
+				case <-s.closed:
+				case s.recv <- msg:
+				}
 			}
 			continue
 		case "discover":
@@ -618,7 +694,7 @@ func (t *tun) listen(link *link) {
 			s, exists = t.getSession(channel, "listener")
 		// only return accept to the session
 		case mtype == "accept":
-			log.Debugf("Received accept message for %s %s", channel, sessionId)
+			log.Debugf("Tunnel received accept message for channel: %s session: %s", channel, sessionId)
 			s, exists = t.getSession(channel, sessionId)
 			if exists && s.accepted {
 				continue
@@ -638,7 +714,7 @@ func (t *tun) listen(link *link) {
 
 		// bail if no session or listener has been found
 		if !exists {
-			log.Debugf("Tunnel skipping no session %s %s exists", channel, sessionId)
+			log.Tracef("Tunnel skipping no channel: %s session: %s exists", channel, sessionId)
 			// drop it, we don't care about
 			// messages we don't know about
 			continue
@@ -651,22 +727,10 @@ func (t *tun) listen(link *link) {
 			delete(t.sessions, channel)
 			continue
 		default:
-			// process
+			// otherwise process
 		}
 
-		log.Debugf("Tunnel using channel %s session %s", s.channel, s.session)
+		log.Tracef("Tunnel using channel: %s session: %s type: %s", s.channel, s.session, mtype)
-
-		// is the session new?
-		select {
-		// if its new the session is actually blocked waiting
-		// for a connection. so we check if its waiting.
-		case <-s.wait:
-		// if its waiting e.g its new then we close it
-		default:
-			// set remote address of the session
-			s.remote = msg.Header["Remote"]
-			close(s.wait)
-		}
 
 		// construct a new transport message
 		tmsg := &transport.Message{
@@ -696,68 +760,26 @@ func (t *tun) listen(link *link) {
 	}
 }
 
-// discover sends channel discover requests periodically
+func (t *tun) sendMsg(method string, link *link) error {
-func (t *tun) discover(link *link) {
+	return link.Send(&transport.Message{
-	tick := time.NewTicker(DiscoverTime)
-	defer tick.Stop()
-
-	for {
-		select {
-		case <-tick.C:
-			// send a discovery message to all links
-			if err := link.Send(&transport.Message{
 		Header: map[string]string{
-					"Micro-Tunnel":    "discover",
+			"Micro-Tunnel":    method,
 			"Micro-Tunnel-Id": t.id,
 		},
-			}); err != nil {
+	})
-				log.Debugf("Tunnel failed to send discover to link %s: %v", link.Remote(), err)
-			}
-		case <-link.closed:
-			return
-		case <-t.closed:
-			return
-		}
-	}
-}
-
-// keepalive periodically sends keepalive messages to link
-func (t *tun) keepalive(link *link) {
-	keepalive := time.NewTicker(KeepAliveTime)
-	defer keepalive.Stop()
-
-	for {
-		select {
-		case <-t.closed:
-			return
-		case <-link.closed:
-			return
-		case <-keepalive.C:
-			// send keepalive message
-			log.Debugf("Tunnel sending keepalive to link: %v", link.Remote())
-			if err := link.Send(&transport.Message{
-				Header: map[string]string{
-					"Micro-Tunnel":    "keepalive",
-					"Micro-Tunnel-Id": t.id,
-				},
-			}); err != nil {
-				log.Debugf("Error sending keepalive to link %v: %v", link.Remote(), err)
-				t.delLink(link.Remote())
-				return
-			}
-		}
-	}
 }
 
 // setupLink connects to node and returns link if successful
 // It returns error if the link failed to be established
 func (t *tun) setupLink(node string) (*link, error) {
 	log.Debugf("Tunnel setting up link: %s", node)
+
 	c, err := t.options.Transport.Dial(node)
 	if err != nil {
 		log.Debugf("Tunnel failed to connect to %s: %v", node, err)
 		return nil, err
 	}
+
 	log.Debugf("Tunnel connected to %s", node)
 
 	// create a new link
@@ -766,12 +788,8 @@ func (t *tun) setupLink(node string) (*link, error) {
 	link.id = c.Remote()
 
 	// send the first connect message
-	if err := link.Send(&transport.Message{
+	if err := t.sendMsg("connect", link); err != nil {
-		Header: map[string]string{
+		link.Close()
-			"Micro-Tunnel":    "connect",
-			"Micro-Tunnel-Id": t.id,
-		},
-	}); err != nil {
 		return nil, err
 	}
 
@@ -782,37 +800,40 @@ func (t *tun) setupLink(node string) (*link, error) {
 	// process incoming messages
 	go t.listen(link)
 
-	// start keepalive monitor
+	// manage keepalives and discovery messages
-	go t.keepalive(link)
+	go t.manageLink(link)
-
-	// discover things on the remote side
-	go t.discover(link)
 
 	return link, nil
 }
 
 func (t *tun) setupLinks() {
+	var wg sync.WaitGroup
+
 	for _, node := range t.options.Nodes {
-		// skip zero length nodes
+		wg.Add(1)
-		if len(node) == 0 {
-			continue
-		}
 
-		// link already exists
+		go func(node string) {
+			defer wg.Done()
+
+			// we're not trying to fix existing links
 			if _, ok := t.links[node]; ok {
-			continue
+				return
 			}
 
-		// connect to node and return link
+			// create new link
 			link, err := t.setupLink(node)
 			if err != nil {
-			log.Debugf("Tunnel failed to establish node link to %s: %v", node, err)
+				log.Debugf("Tunnel failed to setup node link to %s: %v", node, err)
-			continue
+				return
 			}
 
 			// save the link
 			t.links[node] = link
+		}(node)
 	}
+
+	// wait for all threads to finish
+	wg.Wait()
 }
 
 // connect the tunnel to all the nodes and listen for incoming tunnel connections
@@ -833,11 +854,8 @@ func (t *tun) connect() error {
 			// create a new link
 			link := newLink(sock)
 
-			// start keepalive monitor
+			// manage the link
-			go t.keepalive(link)
+			go t.manageLink(link)
-
-			// discover things on the remote side
-			go t.discover(link)
 
 			// listen for inbound messages.
 			// only save the link once connected.
@@ -864,12 +882,13 @@ func (t *tun) Connect() error {
 
 	// already connected
 	if t.connected {
-		// setup links
+		// do it immediately
 		t.setupLinks()
+		// setup links
 		return nil
 	}
 
-	// send the connect message
+	// connect the tunnel: start the listener
 	if err := t.connect(); err != nil {
 		return err
 	}
@@ -879,15 +898,15 @@ func (t *tun) Connect() error {
 	// create new close channel
 	t.closed = make(chan bool)
 
-	// setup links
-	t.setupLinks()
-
 	// process outbound messages to be sent
 	// process sends to all links
 	go t.process()
 
-	// monitor links
+	// call setup before managing them
-	go t.monitor()
+	t.setupLinks()
+
+	// manage the links
+	go t.manage()
 
 	return nil
 }
@@ -1025,7 +1044,9 @@ func (t *tun) Dial(channel string, opts ...DialOption) (Session, error) {
 	// set the multicast option
 	c.mode = options.Mode
 	// set the dial timeout
-	c.timeout = options.Timeout
+	c.dialTimeout = options.Timeout
+	// set read timeout set to never
+	c.readTimeout = time.Duration(-1)
 
 	var links []*link
 	// did we measure the rtt
@@ -1052,7 +1073,7 @@ func (t *tun) Dial(channel string, opts ...DialOption) (Session, error) {
 
 	t.RUnlock()
 
-	// link not found
+	// link not found and one was specified so error out
 	if len(links) == 0 && len(options.Link) > 0 {
 		// delete session and return error
 		t.delSession(c.channel, c.session)
@@ -1061,15 +1082,14 @@ func (t *tun) Dial(channel string, opts ...DialOption) (Session, error) {
 	}
 
 	// discovered so set the link if not multicast
-	// TODO: pick the link efficiently based
-	// on link status and saturation.
 	if c.discovered && c.mode == Unicast {
 		// pickLink will pick the best link
 		link := t.pickLink(links)
+		// set the link
 		c.link = link.id
 	}
 
-	// shit fuck
+	// if its not already discovered we need to attempt to do so
 	if !c.discovered {
 		// piggy back roundtrip
 		nowRTT := time.Now()
@@ -1098,7 +1118,15 @@ func (t *tun) Dial(channel string, opts ...DialOption) (Session, error) {
 		}
 	}
 
-	// a unicast session so we call "open" and wait for an "accept"
+	// return early if its not unicast
+	// we will not call "open" for multicast
+	if c.mode != Unicast {
+		return c, nil
+	}
+
+	// Note: we go no further for multicast or broadcast.
+	// This is a unicast session so we call "open" and wait
+	// for an "accept"
 
 	// reset now in case we use it
 	now := time.Now()
@@ -1115,7 +1143,7 @@ func (t *tun) Dial(channel string, opts ...DialOption) (Session, error) {
 	d := time.Since(now)
 
 	// if we haven't measured the roundtrip do it now
-	if !measured && c.mode == Unicast {
+	if !measured {
 		// set the link time
 		t.RLock()
 		link, ok := t.links[c.link]
@@ -1134,7 +1162,11 @@ func (t *tun) Dial(channel string, opts ...DialOption) (Session, error) {
 func (t *tun) Listen(channel string, opts ...ListenOption) (Listener, error) {
 	log.Debugf("Tunnel listening on %s", channel)
 
-	var options ListenOptions
+	options := ListenOptions{
+		// Read timeout defaults to never
+		Timeout: time.Duration(-1),
+	}
+
 	for _, o := range opts {
 		o(&options)
 	}
@@ -1145,6 +1177,7 @@ func (t *tun) Listen(channel string, opts ...ListenOption) (Listener, error) {
 		return nil, errors.New("already listening on " + channel)
 	}
 
+	// delete function removes the session when closed
 	delFunc := func() {
 		t.delSession(channel, "listener")
 	}
@@ -1155,6 +1188,8 @@ func (t *tun) Listen(channel string, opts ...ListenOption) (Listener, error) {
 	c.local = channel
 	// set mode
 	c.mode = options.Mode
+	// set the timeout
+	c.readTimeout = options.Timeout
 
 	tl := &tunListener{
 		channel: channel,

tunnel/link.go

@@ -2,6 +2,7 @@ package tunnel
 
 import (
 	"bytes"
+	"errors"
 	"io"
 	"sync"
 	"time"
@@ -14,7 +15,11 @@ import (
 type link struct {
 	transport.Socket
 
+	// transport to use for connections
+	transport transport.Transport
+
 	sync.RWMutex
+
 	// stops the link
 	closed chan bool
 	// link state channel for testing link
@@ -65,6 +70,8 @@ var (
 	linkRequest = []byte{0, 0, 0, 0}
 	// the 4 byte 1 filled packet sent to determine link state
 	linkResponse = []byte{1, 1, 1, 1}
+
+	ErrLinkConnectTimeout = errors.New("link connect timeout")
 )
 
 func newLink(s transport.Socket) *link {
@@ -72,8 +79,8 @@ func newLink(s transport.Socket) *link {
 		Socket:        s,
 		id:            uuid.New().String(),
 		lastKeepAlive: time.Now(),
-		channels:      make(map[string]time.Time),
 		closed:        make(chan bool),
+		channels:      make(map[string]time.Time),
 		state:         make(chan *packet, 64),
 		sendQueue:     make(chan *packet, 128),
 		recvQueue:     make(chan *packet, 128),
@@ -87,6 +94,32 @@ func newLink(s transport.Socket) *link {
 	return l
 }
 
+func (l *link) connect(addr string) error {
+	c, err := l.transport.Dial(addr)
+	if err != nil {
+		return err
+	}
+
+	l.Lock()
+	l.Socket = c
+	l.Unlock()
+
+	return nil
+}
+
+func (l *link) accept(sock transport.Socket) error {
+	l.Lock()
+	l.Socket = sock
+	l.Unlock()
+	return nil
+}
+
+func (l *link) setLoopback(v bool) {
+	l.Lock()
+	l.loopback = v
+	l.Unlock()
+}
+
 // setRate sets the bits per second rate as a float64
 func (l *link) setRate(bits int64, delta time.Duration) {
 	// rate of send in bits per nanosecond
@@ -167,6 +200,8 @@ func (l *link) process() {
 				// process link state message
 				select {
 				case l.state <- pk:
+				case <-l.closed:
+					return
 				default:
 				}
 				continue
@@ -188,7 +223,11 @@ func (l *link) process() {
 		select {
 		case pk := <-l.sendQueue:
 			// send the message
-			pk.status <- l.send(pk.message)
+			select {
+			case pk.status <- l.send(pk.message):
+			case <-l.closed:
+				return
+			}
 		case <-l.closed:
 			return
 		}
@@ -201,11 +240,15 @@ func (l *link) manage() {
 	t := time.NewTicker(time.Minute)
 	defer t.Stop()
 
+	// get link id
+	linkId := l.Id()
+
 	// used to send link state packets
 	send := func(b []byte) error {
 		return l.Send(&transport.Message{
 			Header: map[string]string{
 				"Micro-Method":  "link",
+				"Micro-Link-Id": linkId,
 			}, Body: b,
 		})
 	}
@@ -229,9 +272,7 @@ func (l *link) manage() {
 			// check the type of message
 			switch {
 			case bytes.Equal(p.message.Body, linkRequest):
-				l.RLock()
+				log.Tracef("Link %s received link request", linkId)
-				log.Tracef("Link %s received link request %v", l.id, p.message.Body)
-				l.RUnlock()
 
 				// send response
 				if err := send(linkResponse); err != nil {
@@ -242,9 +283,7 @@ func (l *link) manage() {
 			case bytes.Equal(p.message.Body, linkResponse):
 				// set round trip time
 				d := time.Since(now)
-				l.RLock()
+				log.Tracef("Link %s received link response in %v", linkId, d)
-				log.Tracef("Link %s received link response in %v", p.message.Body, d)
-				l.RUnlock()
 				// set the RTT
 				l.setRTT(d)
 			}
@@ -309,6 +348,12 @@ func (l *link) Rate() float64 {
 	return l.rate
 }
 
+func (l *link) Loopback() bool {
+	l.RLock()
+	defer l.RUnlock()
+	return l.loopback
+}
+
 // Length returns the roundtrip time as nanoseconds (lower is better).
 // Returns 0 where no measurement has been taken.
 func (l *link) Length() int64 {
@@ -320,7 +365,6 @@ func (l *link) Length() int64 {
 func (l *link) Id() string {
 	l.RLock()
 	defer l.RUnlock()
-
 	return l.id
 }
 
@@ -350,13 +394,6 @@ func (l *link) Send(m *transport.Message) error {
 	// get time now
 	now := time.Now()
 
-	// check if its closed first
-	select {
-	case <-l.closed:
-		return io.EOF
-	default:
-	}
-
 	// queue the message
 	select {
 	case l.sendQueue <- p:

tunnel/listener.go

@@ -24,7 +24,7 @@ type tunListener struct {
 	delFunc func()
 }
 
-// periodically announce self
+// periodically announce self the channel being listened on
 func (t *tunListener) announce() {
 	tick := time.NewTicker(time.Second * 30)
 	defer tick.Stop()
@@ -48,9 +48,12 @@ func (t *tunListener) process() {
 
 	defer func() {
 		// close the sessions
-		for _, conn := range conns {
+		for id, conn := range conns {
 			conn.Close()
+			delete(conns, id)
 		}
+		// unassign
+		conns = nil
 	}()
 
 	for {
@@ -62,9 +65,24 @@ func (t *tunListener) process() {
 			return
 		// receive a new message
 		case m := <-t.session.recv:
+			var sessionId string
+			var linkId string
+
+			switch m.mode {
+			case Multicast:
+				sessionId = "multicast"
+				linkId = "multicast"
+			case Broadcast:
+				sessionId = "broadcast"
+				linkId = "broadcast"
+			default:
+				sessionId = m.session
+				linkId = m.link
+			}
+
 			// get a session
-			sess, ok := conns[m.session]
+			sess, ok := conns[sessionId]
-			log.Debugf("Tunnel listener received channel %s session %s exists: %t", m.channel, m.session, ok)
+			log.Tracef("Tunnel listener received channel %s session %s type %s exists: %t", m.channel, m.session, m.typ, ok)
 			if !ok {
 				// we only process open and session types
 				switch m.typ {
@@ -80,13 +98,13 @@ func (t *tunListener) process() {
 					// the channel
 					channel: m.channel,
 					// the session id
-					session: m.session,
+					session: sessionId,
 					// tunnel token
 					token: t.token,
 					// is loopback conn
 					loopback: m.loopback,
 					// the link the message was received on
-					link: m.link,
+					link: linkId,
 					// set the connection mode
 					mode: m.mode,
 					// close chan
@@ -95,14 +113,14 @@ func (t *tunListener) process() {
 					recv: make(chan *message, 128),
 					// use the internal send buffer
 					send: t.session.send,
-					// wait
-					wait: make(chan bool),
 					// error channel
 					errChan: make(chan error, 1),
+					// set the read timeout
+					readTimeout: t.session.readTimeout,
 				}
 
 				// save the session
-				conns[m.session] = sess
+				conns[sessionId] = sess
 
 				select {
 				case <-t.closed:
@@ -114,17 +132,19 @@ func (t *tunListener) process() {
 
 			// an existing session was found
 
-			// received a close message
 			switch m.typ {
 			case "close":
+				// received a close message
 				select {
+				// check if the session is closed
 				case <-sess.closed:
 					// no op
-					delete(conns, m.session)
+					delete(conns, sessionId)
 				default:
+					// only close if unicast session
 					// close and delete session
 					close(sess.closed)
-					delete(conns, m.session)
+					delete(conns, sessionId)
 				}
 
 				// continue
@@ -139,9 +159,9 @@ func (t *tunListener) process() {
 			// send this to the accept chan
 			select {
 			case <-sess.closed:
-				delete(conns, m.session)
+				delete(conns, sessionId)
 			case sess.recv <- m:
-				log.Debugf("Tunnel listener sent to recv chan channel %s session %s", m.channel, m.session)
+				log.Tracef("Tunnel listener sent to recv chan channel %s session %s type %s", m.channel, sessionId, m.typ)
 			}
 		}
 	}
@@ -180,6 +200,10 @@ func (t *tunListener) Accept() (Session, error) {
 		if !ok {
 			return nil, io.EOF
 		}
+		// return without accept
+		if c.mode != Unicast {
+			return c, nil
+		}
 		// send back the accept
 		if err := c.Accept(); err != nil {
 			return nil, err

tunnel/options.go

@@ -47,6 +47,8 @@ type ListenOption func(*ListenOptions)
 type ListenOptions struct {
 	// specify mode of the session
 	Mode Mode
+	// The read timeout
+	Timeout time.Duration
 }
 
 // The tunnel id
@@ -84,16 +86,6 @@ func Transport(t transport.Transport) Option {
 	}
 }
 
-// DefaultOptions returns router default options
-func DefaultOptions() Options {
-	return Options{
-		Id:        uuid.New().String(),
-		Address:   DefaultAddress,
-		Token:     DefaultToken,
-		Transport: quic.NewTransport(),
-	}
-}
-
 // Listen options
 func ListenMode(m Mode) ListenOption {
 	return func(o *ListenOptions) {
@@ -101,6 +93,13 @@ func ListenMode(m Mode) ListenOption {
 	}
 }
 
+// Timeout for reads and writes on the listener session
+func ListenTimeout(t time.Duration) ListenOption {
+	return func(o *ListenOptions) {
+		o.Timeout = t
+	}
+}
+
 // Dial options
 
 // Dial multicast sets the multicast option to send only to those mapped
@@ -124,3 +123,13 @@ func DialLink(id string) DialOption {
 		o.Link = id
 	}
 }
+
+// DefaultOptions returns router default options
+func DefaultOptions() Options {
+	return Options{
+		Id:        uuid.New().String(),
+		Address:   DefaultAddress,
+		Token:     DefaultToken,
+		Transport: quic.NewTransport(),
+	}
+}

tunnel/session.go

@@ -2,7 +2,6 @@ package tunnel
 
 import (
 	"encoding/hex"
-	"errors"
 	"io"
 	"time"
 
@@ -30,8 +29,6 @@ type session struct {
 	send chan *message
 	// recv chan
 	recv chan *message
-	// wait until we have a connection
-	wait chan bool
 	// if the discovery worked
 	discovered bool
 	// if the session was accepted
@@ -42,8 +39,10 @@ type session struct {
 	loopback bool
 	// mode of the connection
 	mode Mode
-	// the timeout
+	// the dial timeout
-	timeout time.Duration
+	dialTimeout time.Duration
+	// the read timeout
+	readTimeout time.Duration
 	// the link on which this message was received
 	link string
 	// the error response
@@ -109,65 +108,114 @@ func (s *session) newMessage(typ string) *message {
 	}
 }
 
+func (s *session) sendMsg(msg *message) error {
+	select {
+	case <-s.closed:
+		return io.EOF
+	case s.send <- msg:
+		return nil
+	}
+}
+
+func (s *session) wait(msg *message) error {
+	// wait for an error response
+	select {
+	case err := <-msg.errChan:
+		if err != nil {
+			return err
+		}
+	case <-s.closed:
+		return io.EOF
+	}
+
+	return nil
+}
+
 // waitFor waits for the message type required until the timeout specified
 func (s *session) waitFor(msgType string, timeout time.Duration) (*message, error) {
 	now := time.Now()
 
-	after := func(timeout time.Duration) time.Duration {
+	after := func(timeout time.Duration) <-chan time.Time {
+		if timeout < time.Duration(0) {
+			return nil
+		}
+
+		// get the delta
 		d := time.Since(now)
+
 		// dial timeout minus time since
 		wait := timeout - d
 
 		if wait < time.Duration(0) {
-			return time.Duration(0)
+			wait = time.Duration(0)
 		}
 
-		return wait
+		return time.After(wait)
 	}
 
 	// wait for the message type
 	for {
 		select {
 		case msg := <-s.recv:
+			// there may be no message type
+			if len(msgType) == 0 {
+				return msg, nil
+			}
+
 			// ignore what we don't want
 			if msg.typ != msgType {
 				log.Debugf("Tunnel received non %s message in waiting for %s", msg.typ, msgType)
 				continue
 			}
+
 			// got the message
 			return msg, nil
-		case <-time.After(after(timeout)):
+		case <-after(timeout):
-			return nil, ErrDialTimeout
+			return nil, ErrReadTimeout
 		case <-s.closed:
 			return nil, io.EOF
 		}
 	}
 }
 
-// Discover attempts to discover the link for a specific channel
+// Discover attempts to discover the link for a specific channel.
+// This is only used by the tunnel.Dial when first connecting.
 func (s *session) Discover() error {
 	// create a new discovery message for this channel
 	msg := s.newMessage("discover")
+	// broadcast the message to all links
 	msg.mode = Broadcast
+	// its an outbound connection since we're dialling
 	msg.outbound = true
+	// don't set the link since we don't know where it is
 	msg.link = ""
 
-	// send the discovery message
+	// if multicast then set that as session
-	s.send <- msg
+	if s.mode == Multicast {
+		msg.session = "multicast"
+	}
+
+	// send discover message
+	if err := s.sendMsg(msg); err != nil {
+		return err
+	}
 
 	// set time now
 	now := time.Now()
 
+	// after strips down the dial timeout
 	after := func() time.Duration {
 		d := time.Since(now)
 		// dial timeout minus time since
-		wait := s.timeout - d
+		wait := s.dialTimeout - d
+		// make sure its always > 0
 		if wait < time.Duration(0) {
 			return time.Duration(0)
 		}
 		return wait
 	}
 
+	// the discover message is sent out, now
 	// wait to hear back about the sent message
 	select {
 	case <-time.After(after()):
@@ -178,27 +226,16 @@ func (s *session) Discover() error {
 		}
 	}
 
-	var err error
+	// bail early if its not unicast
-
+	// we don't need to wait for the announce
-	// set a new dialTimeout
-	dialTimeout := after()
-
-	// set a shorter delay for multicast
-	if s.mode != Unicast {
-		// shorten this
-		dialTimeout = time.Millisecond * 500
-	}
-
-	// wait for announce
-	_, err = s.waitFor("announce", dialTimeout)
-
-	// if its multicast just go ahead because this is best effort
 	if s.mode != Unicast {
 		s.discovered = true
 		s.accepted = true
 		return nil
 	}
 
+	// wait for announce
+	_, err := s.waitFor("announce", after())
 	if err != nil {
 		return err
 	}
@@ -210,31 +247,23 @@ func (s *session) Discover() error {
 }
 
 // Open will fire the open message for the session. This is called by the dialler.
+// This is to indicate that we want to create a new session.
 func (s *session) Open() error {
 	// create a new message
 	msg := s.newMessage("open")
 
 	// send open message
-	s.send <- msg
+	if err := s.sendMsg(msg); err != nil {
-
-	// wait for an error response for send
-	select {
-	case err := <-msg.errChan:
-		if err != nil {
 		return err
 	}
-	case <-s.closed:
+
-		return io.EOF
+	// wait for an error response for send
+	if err := s.wait(msg); err != nil {
+		return err
 	}
 
-	// don't wait on multicast/broadcast
+	// now wait for the accept message to be returned
-	if s.mode == Multicast {
+	msg, err := s.waitFor("accept", s.dialTimeout)
-		s.accepted = true
-		return nil
-	}
-
-	// now wait for the accept
-	msg, err := s.waitFor("accept", s.timeout)
 	if err != nil {
 		return err
 	}
@@ -252,32 +281,16 @@ func (s *session) Accept() error {
 	msg := s.newMessage("accept")
 
 	// send the accept message
-	select {
+	if err := s.sendMsg(msg); err != nil {
-	case <-s.closed:
+		return err
-		return io.EOF
-	case s.send <- msg:
-		// no op here
-	}
-
-	// don't wait on multicast/broadcast
-	if s.mode == Multicast {
-		return nil
 	}
 
 	// wait for send response
-	select {
+	return s.wait(msg)
-	case err := <-s.errChan:
-		if err != nil {
-			return err
-		}
-	case <-s.closed:
-		return io.EOF
 }
 
-	return nil
+// Announce sends an announcement to notify that this session exists.
-}
+// This is primarily used by the listener.
-
-// Announce sends an announcement to notify that this session exists. This is primarily used by the listener.
 func (s *session) Announce() error {
 	msg := s.newMessage("announce")
 	// we don't need an error back
@@ -287,23 +300,12 @@ func (s *session) Announce() error {
 	// we don't need the link
 	msg.link = ""
 
-	select {
+	// send announce message
-	case s.send <- msg:
+	return s.sendMsg(msg)
-		return nil
-	case <-s.closed:
-		return io.EOF
-	}
 }
 
 // Send is used to send a message
 func (s *session) Send(m *transport.Message) error {
-	select {
-	case <-s.closed:
-		return io.EOF
-	default:
-		// no op
-	}
-
 	// encrypt the transport message payload
 	body, err := Encrypt(m.Body, s.token+s.channel+s.session)
 	if err != nil {
@@ -335,32 +337,28 @@ func (s *session) Send(m *transport.Message) error {
 	msg.data = data
 
 	// if multicast don't set the link
-	if s.mode == Multicast {
+	if s.mode != Unicast {
 		msg.link = ""
 	}
 
 	log.Tracef("Appending %+v to send backlog", msg)
+
 	// send the actual message
-	s.send <- msg
+	if err := s.sendMsg(msg); err != nil {
+		return err
+	}
 
 	// wait for an error response
-	select {
+	return s.wait(msg)
-	case err := <-msg.errChan:
-		return err
-	case <-s.closed:
-		return io.EOF
-	}
 }
 
 // Recv is used to receive a message
 func (s *session) Recv(m *transport.Message) error {
 	var msg *message
 
-	select {
+	msg, err := s.waitFor("", s.readTimeout)
-	case <-s.closed:
+	if err != nil {
-		return errors.New("session is closed")
+		return err
-	// recv from backlog
-	case msg = <-s.recv:
 	}
 
 	// check the error if one exists
@@ -371,10 +369,13 @@ func (s *session) Recv(m *transport.Message) error {
 	}
 
 	//log.Tracef("Received %+v from recv backlog", msg)
-	log.Debugf("Received %+v from recv backlog", msg)
+	log.Tracef("Received %+v from recv backlog", msg)
 
 	// decrypt the received payload using the token
-	body, err := Decrypt(msg.data.Body, s.token+s.channel+s.session)
+	// we have to used msg.session because multicast has a shared
+	// session id of "multicast" in this session struct on
+	// the listener side
+	body, err := Decrypt(msg.data.Body, s.token+s.channel+msg.session)
 	if err != nil {
 		log.Debugf("failed to decrypt message body: %v", err)
 		return err
@@ -390,7 +391,7 @@ func (s *session) Recv(m *transport.Message) error {
 			return err
 		}
 		// encrypt the transport message payload
-		val, err := Decrypt([]byte(h), s.token+s.channel+s.session)
+		val, err := Decrypt([]byte(h), s.token+s.channel+msg.session)
 		if err != nil {
 			log.Debugf("failed to decrypt message header %s: %v", k, err)
 			return err
@@ -399,6 +400,12 @@ func (s *session) Recv(m *transport.Message) error {
 		msg.data.Header[k] = string(val)
 	}
 
+	// set the link
+	// TODO: decruft, this is only for multicast
+	// since the session is now a single session
+	// likely provide as part of message.Link()
+	msg.data.Header["Micro-Link"] = msg.link
+
 	// set message
 	*m = *msg.data
 	// return nil
@@ -413,6 +420,11 @@ func (s *session) Close() error {
 	default:
 		close(s.closed)
 
+		// don't send close on multicast or broadcast
+		if s.mode != Unicast {
+			return nil
+		}
+
 		// append to backlog
 		msg := s.newMessage("close")
 		// no error response on close
@@ -421,7 +433,7 @@ func (s *session) Close() error {
 		// send the close message
 		select {
 		case s.send <- msg:
-		default:
+		case <-time.After(time.Millisecond * 10):
 		}
 	}
 

tunnel/tunnel.go

@@ -26,6 +26,8 @@ var (
 	ErrDiscoverChan = errors.New("failed to discover channel")
 	// ErrLinkNotFound is returned when a link is specified at dial time and does not exist
 	ErrLinkNotFound = errors.New("link not found")
+	// ErrReadTimeout is a timeout on session.Recv
+	ErrReadTimeout = errors.New("read timeout")
 )
 
 // Mode of the session
@@ -64,7 +66,9 @@ type Link interface {
 	Length() int64
 	// Current transfer rate as bits per second (lower is better)
 	Rate() float64
-	// State of the link e.g connected/closed
+	// Is this a loopback link
+	Loopback() bool
+	// State of the link: connected/closed/error
 	State() string
 	// honours transport socket
 	transport.Socket

tunnel/tunnel_reconnect_test.go

@@ -1,55 +0,0 @@
-// +build !race
-
-package tunnel
-
-import (
-	"sync"
-	"testing"
-	"time"
-)
-
-func TestReconnectTunnel(t *testing.T) {
-	// create a new tunnel client
-	tunA := NewTunnel(
-		Address("127.0.0.1:9096"),
-		Nodes("127.0.0.1:9097"),
-	)
-
-	// create a new tunnel server
-	tunB := NewTunnel(
-		Address("127.0.0.1:9097"),
-	)
-
-	// start tunnel
-	err := tunB.Connect()
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer tunB.Close()
-
-	// we manually override the tunnel.ReconnectTime value here
-	// this is so that we make the reconnects faster than the default 5s
-	ReconnectTime = 200 * time.Millisecond
-
-	// start tunnel
-	err = tunA.Connect()
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer tunA.Close()
-
-	wait := make(chan bool)
-
-	var wg sync.WaitGroup
-
-	wg.Add(1)
-	// start tunnel listener
-	go testBrokenTunAccept(t, tunB, wait, &wg)
-
-	wg.Add(1)
-	// start tunnel sender
-	go testBrokenTunSend(t, tunA, wait, &wg)
-
-	// wait until done
-	wg.Wait()
-}

tunnel/tunnel_test.go

@@ -8,6 +8,90 @@ import (
 	"github.com/micro/go-micro/transport"
 )
 
+func testBrokenTunAccept(t *testing.T, tun Tunnel, wait chan bool, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	// listen on some virtual address
+	tl, err := tun.Listen("test-tunnel")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// receiver ready; notify sender
+	wait <- true
+
+	// accept a connection
+	c, err := tl.Accept()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// accept the message and close the tunnel
+	// we do this to simulate loss of network connection
+	m := new(transport.Message)
+	if err := c.Recv(m); err != nil {
+		t.Fatal(err)
+	}
+
+	// close all the links
+	for _, link := range tun.Links() {
+		link.Close()
+	}
+
+	// receiver ready; notify sender
+	wait <- true
+
+	// accept the message
+	m = new(transport.Message)
+	if err := c.Recv(m); err != nil {
+		t.Fatal(err)
+	}
+
+	// notify the sender we have received
+	wait <- true
+}
+
+func testBrokenTunSend(t *testing.T, tun Tunnel, wait chan bool, wg *sync.WaitGroup, reconnect time.Duration) {
+	defer wg.Done()
+
+	// wait for the listener to get ready
+	<-wait
+
+	// dial a new session
+	c, err := tun.Dial("test-tunnel")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	m := transport.Message{
+		Header: map[string]string{
+			"test": "send",
+		},
+	}
+
+	// send the message
+	if err := c.Send(&m); err != nil {
+		t.Fatal(err)
+	}
+
+	// wait for the listener to get ready
+	<-wait
+
+	// give it time to reconnect
+	time.Sleep(reconnect)
+
+	// send the message
+	if err := c.Send(&m); err != nil {
+		t.Fatal(err)
+	}
+
+	// wait for the listener to receive the message
+	// c.Send merely enqueues the message to the link send queue and returns
+	// in order to verify it was received we wait for the listener to tell us
+	<-wait
+}
+
 // testAccept will accept connections on the transport, create a new link and tunnel on top
 func testAccept(t *testing.T, tun Tunnel, wait chan bool, wg *sync.WaitGroup) {
 	defer wg.Done()
@@ -163,90 +247,6 @@ func TestLoopbackTunnel(t *testing.T) {
 	wg.Wait()
 }
 
-func testBrokenTunAccept(t *testing.T, tun Tunnel, wait chan bool, wg *sync.WaitGroup) {
-	defer wg.Done()
-
-	// listen on some virtual address
-	tl, err := tun.Listen("test-tunnel")
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	// receiver ready; notify sender
-	wait <- true
-
-	// accept a connection
-	c, err := tl.Accept()
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	// accept the message and close the tunnel
-	// we do this to simulate loss of network connection
-	m := new(transport.Message)
-	if err := c.Recv(m); err != nil {
-		t.Fatal(err)
-	}
-
-	// close all the links
-	for _, link := range tun.Links() {
-		link.Close()
-	}
-
-	// receiver ready; notify sender
-	wait <- true
-
-	// accept the message
-	m = new(transport.Message)
-	if err := c.Recv(m); err != nil {
-		t.Fatal(err)
-	}
-
-	// notify the sender we have received
-	wait <- true
-}
-
-func testBrokenTunSend(t *testing.T, tun Tunnel, wait chan bool, wg *sync.WaitGroup) {
-	defer wg.Done()
-
-	// wait for the listener to get ready
-	<-wait
-
-	// dial a new session
-	c, err := tun.Dial("test-tunnel")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer c.Close()
-
-	m := transport.Message{
-		Header: map[string]string{
-			"test": "send",
-		},
-	}
-
-	// send the message
-	if err := c.Send(&m); err != nil {
-		t.Fatal(err)
-	}
-
-	// wait for the listener to get ready
-	<-wait
-
-	// give it time to reconnect
-	time.Sleep(5 * ReconnectTime)
-
-	// send the message
-	if err := c.Send(&m); err != nil {
-		t.Fatal(err)
-	}
-
-	// wait for the listener to receive the message
-	// c.Send merely enqueues the message to the link send queue and returns
-	// in order to verify it was received we wait for the listener to tell us
-	<-wait
-}
-
 func TestTunnelRTTRate(t *testing.T) {
 	// create a new tunnel client
 	tunA := NewTunnel(
@@ -296,3 +296,49 @@ func TestTunnelRTTRate(t *testing.T) {
 		t.Logf("Link %s length %v rate %v", link.Id(), link.Length(), link.Rate())
 	}
 }
+
+func TestReconnectTunnel(t *testing.T) {
+	// we manually override the tunnel.ReconnectTime value here
+	// this is so that we make the reconnects faster than the default 5s
+	ReconnectTime = 200 * time.Millisecond
+
+	// create a new tunnel client
+	tunA := NewTunnel(
+		Address("127.0.0.1:9098"),
+		Nodes("127.0.0.1:9099"),
+	)
+
+	// create a new tunnel server
+	tunB := NewTunnel(
+		Address("127.0.0.1:9099"),
+	)
+
+	// start tunnel
+	err := tunB.Connect()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer tunB.Close()
+
+	// start tunnel
+	err = tunA.Connect()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer tunA.Close()
+
+	wait := make(chan bool)
+
+	var wg sync.WaitGroup
+
+	wg.Add(1)
+	// start tunnel listener
+	go testBrokenTunAccept(t, tunB, wait, &wg)
+
+	wg.Add(1)
+	// start tunnel sender
+	go testBrokenTunSend(t, tunA, wait, &wg, ReconnectTime*5)
+
+	// wait until done
+	wg.Wait()
+}