Listen-Accept-Read-Write pattern now works, amazingly

src/yggdrasil/conn.go

@@ -61,11 +61,10 @@ func (c *Conn) startSearch() {
 
 func (c *Conn) Read(b []byte) (int, error) {
 	if c.session == nil {
-		return 0, errors.New("session not open")
+		return 0, errors.New("session not ready yet")
 	}
 	if !c.session.init {
-		// To prevent blocking forever on a session that isn't initialised
-		return 0, errors.New("session not initialised")
+		return 0, errors.New("waiting for remote side to accept")
 	}
 	select {
 	case p, ok := <-c.session.recv:
@@ -84,6 +83,7 @@ func (c *Conn) Read(b []byte) (int, error) {
 				util.PutBytes(bs)
 				return errors.New("packet dropped due to decryption failure")
 			}
+			//	c.core.log.Println("HOW MANY BYTES?", len(bs))
 			b = b[:0]
 			b = append(b, bs...)
 			c.session.updateNonce(&p.Nonce)
@@ -96,7 +96,7 @@ func (c *Conn) Read(b []byte) (int, error) {
 		atomic.AddUint64(&c.session.bytesRecvd, uint64(len(b)))
 		return len(b), nil
 	case <-c.session.closed:
-		return len(b), errors.New("session was closed")
+		return len(b), errors.New("session closed")
 	}
 }
 
@@ -105,12 +105,12 @@ func (c *Conn) Write(b []byte) (bytesWritten int, err error) {
 		c.core.router.doAdmin(func() {
 			c.startSearch()
 		})
-		return 0, errors.New("session not open")
+		return 0, errors.New("session not ready yet")
 	}
 	defer util.PutBytes(b)
 	if !c.session.init {
 		// To prevent using empty session keys
-		return 0, errors.New("session not initialised")
+		return 0, errors.New("waiting for remote side to accept")
 	}
 	// code isn't multithreaded so appending to this is safe
 	coords := c.session.coords
@@ -130,13 +130,14 @@ func (c *Conn) Write(b []byte) (bytesWritten int, err error) {
 	select {
 	case c.session.send <- packet:
 	case <-c.session.closed:
-		return len(b), errors.New("session was closed")
+		return len(b), errors.New("session closed")
 	}
 	c.session.core.router.out(packet)
 	return len(b), nil
 }
 
 func (c *Conn) Close() error {
+	c.session.close()
 	return nil
 }
 

src/yggdrasil/core.go

@@ -254,6 +254,20 @@ func (c *Core) Stop() {
 	c.admin.close()
 }
 
+// ListenConn returns a listener for Yggdrasil session connections.
+func (c *Core) ListenConn() (*Listener, error) {
+	c.sessions.listenerMutex.Lock()
+	defer c.sessions.listenerMutex.Unlock()
+	if c.sessions.listener != nil {
+		return nil, errors.New("a listener already exists")
+	}
+	c.sessions.listener = &Listener{
+		conn:  make(chan *Conn),
+		close: make(chan interface{}),
+	}
+	return c.sessions.listener, nil
+}
+
 // Dial opens a session to the given node. The first paramter should be "nodeid"
 // and the second parameter should contain a hexadecimal representation of the
 // target node ID.

src/yggdrasil/listener.go

@@ -0,0 +1,41 @@
+package yggdrasil
+
+import (
+	"errors"
+	"net"
+)
+
+// Listener waits for incoming sessions
+type Listener struct {
+	conn  chan *Conn
+	close chan interface{}
+}
+
+// Accept blocks until a new incoming session is received
+func (l *Listener) Accept() (*Conn, error) {
+	select {
+	case c, ok := <-l.conn:
+		if !ok {
+			return nil, errors.New("listener closed")
+		}
+		return c, nil
+	case <-l.close:
+		return nil, errors.New("listener closed")
+	}
+}
+
+// Close will stop the listener
+func (l *Listener) Close() (err error) {
+	defer func() {
+		recover()
+		err = errors.New("already closed")
+	}()
+	close(l.close)
+	close(l.conn)
+	return nil
+}
+
+// Addr is not implemented for this type yet
+func (l *Listener) Addr() net.Addr {
+	return nil
+}

src/yggdrasil/session.go

@@ -106,6 +106,8 @@ func (s *sessionInfo) timedout() bool {
 // Additionally, stores maps of address/subnet onto keys, and keys onto handles.
 type sessions struct {
 	core          *Core
+	listener      *Listener
+	listenerMutex sync.Mutex
 	reconfigure   chan chan error
 	lastCleanup   time.Time
 	permShared    map[crypto.BoxPubKey]*crypto.BoxSharedKey // Maps known permanent keys to their shared key, used by DHT a lot
@@ -461,6 +463,22 @@ func (ss *sessions) handlePing(ping *sessionPing) {
 		if !isIn {
 			panic("This should not happen")
 		}
+		ss.listenerMutex.Lock()
+		if ss.listener != nil {
+			conn := &Conn{
+				core:     ss.core,
+				session:  sinfo,
+				nodeID:   crypto.GetNodeID(&sinfo.theirPermPub),
+				nodeMask: &crypto.NodeID{},
+			}
+			for i := range conn.nodeMask {
+				conn.nodeMask[i] = 0xFF
+			}
+			ss.listener.conn <- conn
+		} else {
+			ss.core.log.Debugln("Received new session but there is no listener, ignoring")
+		}
+		ss.listenerMutex.Unlock()
 	}
 	// Update the session
 	if !sinfo.update(ping) { /*panic("Should not happen in testing")*/