Clean up a bit

src/yggdrasil/api.go

@@ -235,8 +235,8 @@ func (c *Core) PacketConn() *PacketConn {
 // Resolve takes a masked node ID and performs a search, returning the complete
 // node ID and the node's public key.
 func (c *Core) Resolve(nodeID, nodeMask *crypto.NodeID) (fullNodeID *crypto.NodeID, boxPubKey *crypto.BoxPubKey, err error) {
-	fmt.Println("**** START RESOLVE")
-	defer fmt.Println("**** END RESOLVE")
+	c.log.Debugln("Resolving", nodeID.String())
+	defer c.log.Debugln("Finished resolving", nodeID.String())
 
 	done := make(chan struct{})
 	c.router.Act(c, func() {
@@ -261,7 +261,7 @@ func (c *Core) Resolve(nodeID, nodeMask *crypto.NodeID) (fullNodeID *crypto.Node
 			}
 			c.router.searches.newIterSearch(nodeID, nodeMask, searchCompleted).startSearch()
 		} else {
-			err = errors.New("search already exists")
+			err = errors.New("a search for this node ID is already in progress")
 			close(done)
 		}
 	})

src/yggdrasil/packetconn.go

@@ -59,54 +59,74 @@ func (c *PacketConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
 }
 
 // implements net.PacketConn
-func (c *PacketConn) WriteTo(b []byte, addr net.Addr) (int, error) {
+func (c *PacketConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
 	if c.closed { // TODO: unsafe?
 		return 0, PacketConnError{closed: true}
 	}
 
+	// Make sure that the net.Addr we were given was actually a
+	// *crypto.BoxPubKey. If it wasn't then fail.
 	boxPubKey, ok := addr.(*crypto.BoxPubKey)
 	if !ok {
 		return 0, errors.New("expected *crypto.BoxPubKey as net.Addr")
 	}
+
+	// Work out the node ID for the public key we were given. If
+	// we need to perform a search then we will need to know this.
 	nodeID := crypto.GetNodeID(boxPubKey)
 	nodeMask := &crypto.NodeID{}
 	for i := range nodeMask {
 		nodeMask[i] = 0xFF
 	}
 
-	// TODO: This is all a mess
-	var err error
+	// Look up if we have an open session for that destination.
 	var session *sessionInfo
 	phony.Block(c.sessions.router, func() {
 		session, ok = c.sessions.getByTheirPerm(boxPubKey)
 	})
+
+	// If we don't have an open session then we will need to perform
+	// a search to find the coordinates for the node. Doing this will
+	// implicitly open a session to the remote node.
 	if !ok {
-		nodeID, boxPubKey, err = c.sessions.router.core.Resolve(nodeID, nodeMask)
-		if err == nil {
-			phony.Block(c.sessions.router, func() {
-				session, ok = c.sessions.getByTheirPerm(boxPubKey)
-			})
+		// Try and look up the node ID and mask.
+		if nodeID, boxPubKey, err = c.sessions.router.core.Resolve(nodeID, nodeMask); err != nil {
+			return 0, fmt.Errorf("search failed: %w", err)
+		}
+
+		// The previous function will block until it is done and by
+		// that point we should have a session. Try to retrieve it.
+		phony.Block(c.sessions.router, func() {
+			session, ok = c.sessions.getByTheirPerm(boxPubKey)
+		})
+
+		// If we still don't have an open session then something's
+		// gone wrong. Give up at this point.
+		if !ok || session == nil {
+			return 0, errors.New("session is not open")
 		}
 	}
-	if err != nil {
-		return 0, fmt.Errorf("failed to find session/start search: %w", err)
-	}
-	if !ok || session == nil {
-		return 0, errors.New("expected a session but there was none")
-	}
 
+	// Delegate to the sessions actor to actually send the message
+	// through the session. We'll wait on the sendErr channel for
+	// the actor to finish at least the initial checks.
 	sendErr := make(chan error, 1)
 	msg := FlowKeyMessage{Message: b}
-
 	session.Act(c, func() {
-		// Check if the packet is small enough to go through this session
+		// Check if the packet is small enough to go through this session.
+		// If it isn't then we'll send back an error with the maximum
+		// session MTU. The sender can decide what to do with it.
 		sessionMTU := session._getMTU()
 		if types.MTU(len(b)) > sessionMTU {
 			sendErr <- PacketConnError{maxsize: int(sessionMTU)}
 			return
 		}
 
-		// Send the packet
+		// If we got to this point then our initial checks passed - there
+		// isn't much point blocking the sender any further so release it.
+		sendErr <- nil
+
+		// Send the packet.
 		session._send(msg)
 
 		// Session keep-alive, while we wait for the crypto workers from send
@@ -115,28 +135,33 @@ func (c *PacketConn) WriteTo(b []byte, addr net.Addr) (int, error) {
 			if session.time.Before(session.pingTime) && time.Since(session.pingTime) > 6*time.Second {
 				// TODO double check that the above condition is correct
 				c.sessions.router.Act(session, func() {
-					// Check to see if there is a search already matching the destination
+					// Check to see if there is a search already matching the
+					// supplied destination. If there is then don't start another
+					// one.
 					sinfo, isIn := c.sessions.router.searches.searches[*nodeID]
 					if !isIn {
-						// Nothing was found, so create a new search
+						// Nothing was found, so create a new search.
 						searchCompleted := func(sinfo *sessionInfo, e error) {}
 						sinfo = c.sessions.router.searches.newIterSearch(nodeID, nodeMask, searchCompleted)
-						c.sessions.router.core.log.Debugf("DHT search started: %p", sinfo)
-						// Start the search
+
+						// Start the search.
 						sinfo.startSearch()
+						c.sessions.router.core.log.Debugf("DHT search started: %p", sinfo)
 					}
 				})
 			} else {
-				session.ping(session) // TODO send from self if this becomes an actor
+				session._sendPingPong(false)
 			}
-		case session.reset && session.pingTime.Before(session.time):
-			session.ping(session) // TODO send from self if this becomes an actor
-		default: // Don't do anything, to keep traffic throttled
-		}
 
-		sendErr <- nil
+		case session.reset && session.pingTime.Before(session.time):
+			session._sendPingPong(false)
+
+		default:
+		}
 	})
 
+	// Wait for the checks to pass. Then return the success
+	// values to the caller.
 	err = <-sendErr
 	return len(b), err
 }