add further comments to tunnel

network/tunnel/default.go

@@ -13,19 +13,21 @@ import (
 
 // tun represents a network tunnel
 type tun struct {
+	// the link on top of which we build a tunnel
 	link link.Link
 
 	sync.RWMutex
 
-	// connect
+	// to indicate if we're connected or not
 	connected bool
 
-	// the send channel
+	// the send channel for all messages
 	send chan *message
+
 	// close channel
 	closed chan bool
 
-	// sockets
+	// a map of sockets based on Micro-Tunnel-Id
 	sockets map[string]*socket
 }
 
@@ -39,6 +41,7 @@ func newTunnel(link link.Link) *tun {
 	}
 }
 
+// getSocket returns a socket from the internal socket map
 func (t *tun) getSocket(id string) (*socket, bool) {
 	// get the socket
 	t.RLock()
@@ -47,6 +50,7 @@ func (t *tun) getSocket(id string) (*socket, bool) {
 	return s, ok
 }
 
+// newSocket creates a new socket and saves it
 func (t *tun) newSocket(id string) *socket {
 	// new id if it doesn't exist
 	if len(id) == 0 {
@@ -81,7 +85,7 @@ func (t *tun) newSession() string {
 	return uuid.New().String()
 }
 
-// process outgoing messages
+// process outgoing messages sent by all local sockets
 func (t *tun) process() {
 	// manage the send buffer
 	// all pseudo sockets throw everything down this
@@ -129,7 +133,8 @@ func (t *tun) listen() {
 		// get the socket
 		s, exists := t.getSocket(id)
 		if !exists {
-			// no op
+			// drop it, we don't care about 
+			// messages we don't know about
 			continue
 		}
 
@@ -145,24 +150,35 @@ func (t *tun) listen() {
 
 		// is the socket new?
 		select {
-		// if its new it will block here
+		// if its new the socket is actually blocked waiting
+		// for a connection. so we check if its waiting.
 		case <-s.wait:
-			// its not new
+		// if its waiting e.g its new then we close it
 		default:
-			// its new
 			// set remote address of the socket
 			s.remote = msg.Header["Remote"]
 			close(s.wait)
 		}
 
+		// construct a new transport message
 		tmsg := &transport.Message{
 			Header: msg.Header,
 			Body:   msg.Body,
 		}
 
-		// TODO: don't block on queuing
+		// construct the internal message
+		imsg := &message{
+			id: id,
+			session: session,
+			data: tmsg,
+		}
+
 		// append to recv backlog
-		s.recv <- &message{id: id, session: session, data: tmsg}
+		// we don't block if we can't pass it on
+		select {
+		case s.recv <- imsg:
+		default:
+		}
 	}
 }