Remove dead link code

tunnel/default.go

@@ -932,6 +932,11 @@ func (t *tun) Dial(channel string, opts ...DialOption) (Session, error) {
 	// non multicast so we need to find the link
 	t.RLock()
 	for _, link := range t.links {
+		// use the link specified it its available
+		if id := options.Link; len(id) > 0 && link.id != id {
+			continue
+		}
+
 		link.RLock()
 		_, ok := link.channels[channel]
 		link.RUnlock()
@@ -944,6 +949,11 @@ func (t *tun) Dial(channel string, opts ...DialOption) (Session, error) {
 	}
 	t.RUnlock()
 
+	// link not found
+	if len(links) == 0 && len(options.Link) > 0 {
+		return nil, ErrLinkNotFound
+	}
+
 	// discovered so set the link if not multicast
 	// TODO: pick the link efficiently based
 	// on link status and saturation.

tunnel/link.go

@@ -1,7 +1,6 @@
 package tunnel
 
 import (
-	"io"
 	"sync"
 	"time"
 
@@ -32,98 +31,19 @@ type link struct {
 	lastKeepAlive time.Time
 	// channels keeps a mapping of channels and last seen
 	channels map[string]time.Time
-
-	// the send queue to the socket
-	sendQueue chan *transport.Message
-	// the recv queue to the socket
-	recvQueue chan *transport.Message
-
-	// determines the cost of the link
-	// based on queue length and roundtrip
-	length int
-	weight int
 }
 
 func newLink(s transport.Socket) *link {
 	l := &link{
-		Socket:    s,
-		id:        uuid.New().String(),
-		channels:  make(map[string]time.Time),
-		closed:    make(chan bool),
-		sendQueue: make(chan *transport.Message, 128),
-		recvQueue: make(chan *transport.Message, 128),
+		Socket:   s,
+		id:       uuid.New().String(),
+		channels: make(map[string]time.Time),
+		closed:   make(chan bool),
 	}
 	go l.expiry()
-	go l.process()
 	return l
 }
 
-// process processes messages on the send and receive queues.
-func (l *link) process() {
-	go func() {
-		for {
-			m := new(transport.Message)
-			if err := l.Socket.Recv(m); err != nil {
-				return
-			}
-
-			select {
-			case l.recvQueue <- m:
-			case <-l.closed:
-				return
-			}
-		}
-	}()
-
-	// messages sent
-	i := 0
-	length := 0
-
-	for {
-		select {
-		case m := <-l.sendQueue:
-			t := time.Now()
-
-			// send the message
-			if err := l.Socket.Send(m); err != nil {
-				return
-			}
-
-			// get header size, body size and time taken
-			hl := len(m.Header)
-			bl := len(m.Body)
-			d := time.Since(t)
-
-			// don't calculate on empty messages
-			if hl == 0 && bl == 0 {
-				continue
-			}
-
-			// increment sent
-			i++
-
-			// time take to send some bits and bytes
-			td := float64(hl+bl) / float64(d.Nanoseconds())
-			// increase the scale
-			td += 1
-
-			// judge the length
-			length = int(td) / (length + int(td))
-
-			// every 10 messages update length
-			if (i % 10) == 1 {
-				// cost average the length
-				// save it
-				l.Lock()
-				l.length = length
-				l.Unlock()
-			}
-		case <-l.closed:
-			return
-		}
-	}
-}
-
 // watches the channel expiry
 func (l *link) expiry() {
 	t := time.NewTicker(time.Minute)
@@ -180,41 +100,6 @@ func (l *link) Close() error {
 	return nil
 }
 
-// length/rate of the link
-func (l *link) Length() int {
-	l.RLock()
-	defer l.RUnlock()
-	return l.length
-}
-
-// weight checks the size of the queues
-func (l *link) Weight() int {
-	return len(l.sendQueue) + len(l.recvQueue)
-}
-
-// Accept accepts a message on the socket
-func (l *link) Recv(m *transport.Message) error {
-	select {
-	case <-l.closed:
-		return io.EOF
-	case rm := <-l.recvQueue:
-		*m = *rm
-		return nil
-	}
-	// never reach
-	return nil
-}
-
-// Send sends a message on the socket immediately
-func (l *link) Send(m *transport.Message) error {
-	select {
-	case <-l.closed:
-		return io.EOF
-	case l.sendQueue <- m:
-	}
-	return nil
-}
-
 func (l *link) Status() string {
 	select {
 	case <-l.closed:

tunnel/options.go

@@ -34,6 +34,8 @@ type Options struct {
 type DialOption func(*DialOptions)
 
 type DialOptions struct {
+	// Link specifies the link to use
+	Link string
 	// specify a multicast connection
 	Multicast bool
 	// the dial timeout
@@ -94,8 +96,17 @@ func DialMulticast() DialOption {
 	}
 }
 
+// DialTimeout sets the dial timeout of the connection
 func DialTimeout(t time.Duration) DialOption {
 	return func(o *DialOptions) {
 		o.Timeout = t
 	}
 }
+
+// DialLink specifies the link to pin this connection to.
+// This is not applicable if the multicast option is set.
+func DialLink(id string) DialOption {
+	return func(o *DialOptions) {
+		o.Link = id
+	}
+}

tunnel/tunnel.go

@@ -15,6 +15,8 @@ var (
 	ErrDialTimeout = errors.New("dial timeout")
 	// ErrDiscoverChan is returned when we failed to receive the "announce" back from a discovery
 	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")
 )
 
 // Tunnel creates a gre tunnel on top of the go-micro/transport.