implemented contextualized waiting for peers

introduced new functions with `WithContext` suffix to not break API compatibility.

Author: jmgraeffe

api/smp.go

@@ -207,6 +207,66 @@ func (mp *MPPeerSock) WaitForPeerConnect(sel pathselection.CustomPathSelection)
 	return remote, err
 }
 
+//
+// This method waits until a remote MPPeerSock calls connect to this
+// socket's local address
+// A pathselection may be passed, which lets the socket dialing back to its remote
+// (e.g. for server-side path selection)
+// Since the MPPeerSock waits for only one incoming connection to determine a new peer
+// it starts waiting for other connections (if no selection passed) and fires the
+// OnConnectionsChange event for each new incoming connection
+//
+func (mp *MPPeerSock) WaitForPeerConnectWithContext(ctx context.Context, sel pathselection.CustomPathSelection) (*snet.UDPAddr, error) {
+	log.Debugf("Waiting for incoming connection")
+	remote, err := mp.UnderlaySocket.WaitForDialInWithContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	log.Debugf("Accepted connection from %s", remote.String())
+	mp.Peer = remote
+	mp.selection = sel
+	// Start selection process -> will update DB
+	mp.StartPathSelection(sel, sel == nil)
+	log.Debugf("Done path selection")
+	// wait until first signal on channel
+	// selectedPathSet := <-mp.OnPathsetChange
+	// time.Sleep(1 * time.Second)
+	// dial all paths selected by user algorithm
+	if sel != nil {
+		err = mp.DialAll(mp.SelectedPathSet, &socket.ConnectOptions{
+			SendAddrPacket: false,
+		})
+		mp.collectMetrics()
+	} else {
+		mp.collectMetrics()
+		go func() {
+			conns := mp.UnderlaySocket.GetConnections()
+			mp.PacketScheduler.SetConnections(conns)
+			mp.PathQualityDB.SetConnections(conns)
+			mp.connectionSetChange(conns)
+			for {
+				log.Debugf("Waiting for new connections...")
+				conn, err := mp.UnderlaySocket.WaitForIncomingConnWithContext(ctx)
+				if conn == nil && err == nil {
+					log.Debugf("Socket does not implement WaitForIncomingConn, stopping here...")
+					return
+				}
+				if err != nil {
+					log.Errorf("Failed to wait for incoming connection %s", err.Error())
+					return
+				}
+
+				conns := mp.UnderlaySocket.GetConnections()
+				mp.PacketScheduler.SetConnections(conns)
+				mp.PathQualityDB.SetConnections(conns)
+				mp.connectionSetChange(conns)
+			}
+		}()
+	}
+
+	return remote, err
+}
+
 func (mp *MPPeerSock) collectMetrics() {
 	mp.metricsTicker = time.NewTicker(mp.MetricsInterval)
 	go func() {

socket/quicsocket.go

@@ -137,6 +137,70 @@ func (s *QUICSocket) WaitForIncomingConn() (packets.UDPConn, error) {
 	}
 }
 
+func (s *QUICSocket) WaitForIncomingConnWithContext(ctx context.Context) (packets.UDPConn, error) {
+	if s.options == nil || !s.options.MultiportMode {
+		log.Debugf("Waiting for new connection")
+		stream, err := s.listenConns[0].AcceptStreamWithContext(ctx)
+		if err != nil {
+			log.Fatalf("QUIC Accept err %s", err.Error())
+		}
+
+		log.Debugf("Accepted new Stream on listen socket")
+
+		bts := make([]byte, packets.PACKET_SIZE)
+		_, err = stream.Read(bts)
+
+		if s.listenConns[0].GetInternalConn() == nil {
+			s.listenConns[0].SetStream(stream)
+			select {
+			case s.listenConns[0].Ready <- true:
+			default:
+			}
+
+			return s.listenConns[0], nil
+		} else {
+			newConn := &packets.QUICReliableConn{}
+			id := RandStringBytes(32)
+			newConn.SetId(id)
+			newConn.SetLocal(*s.localAddr)
+			newConn.SetRemote(s.listenConns[0].GetRemote())
+			newConn.SetStream(stream)
+			s.listenConns = append(s.listenConns, newConn)
+
+			_, err = stream.Read(bts)
+			if err != nil {
+				return nil, err
+			}
+			return newConn, nil
+		}
+	} else {
+		addr := s.localAddr.Copy()
+		addr.Host.Port = s.localAddr.Host.Port + len(s.listenConns)
+		conn := &packets.QUICReliableConn{}
+		err := conn.Listen(*addr)
+		if err != nil {
+			return nil, err
+		}
+
+		stream, err := conn.AcceptStreamWithContext(ctx)
+		if err != nil {
+			return nil, err
+		}
+
+		id := RandStringBytes(32)
+		conn.SetId(id)
+
+		conn.SetStream(stream)
+		s.listenConns = append(s.listenConns, conn)
+		bts := make([]byte, packets.PACKET_SIZE)
+		_, err = stream.Read(bts)
+		if err != nil {
+			return nil, err
+		}
+		return conn, nil
+	}
+}
+
 func (s *QUICSocket) WaitForDialIn() (*snet.UDPAddr, error) {
 	bts := make([]byte, packets.PACKET_SIZE)
 	log.Debugf("Wait for Dial In")
@@ -210,7 +274,7 @@ func (s *QUICSocket) WaitForDialInWithContext(ctx context.Context) (*snet.UDPAdd
 	log.Debugf("Waiting for %d more connections", p.NumPaths-1)
 
 	for i := 1; i < p.NumPaths; i++ {
-		_, err := s.WaitForIncomingConn()
+		_, err := s.WaitForIncomingConnWithContext(ctx)
 		if err != nil {
 			return nil, err
 		}

socket/scionsocket.go

@@ -140,6 +140,10 @@ func (s *SCIONSocket) WaitForIncomingConn() (packets.UDPConn, error) {
 	return nil, nil
 }
 
+func (s *SCIONSocket) WaitForIncomingConnWithContext(ctx context.Context) (packets.UDPConn, error) {
+	return nil, nil
+}
+
 func (s *SCIONSocket) DialAll(remote snet.UDPAddr, path []pathselection.PathQuality, options DialOptions) ([]packets.UDPConn, error) {
 	// There is always one listening connection
 	conns := make([]packets.UDPConn, 1)

socket/socket.go

@@ -29,6 +29,7 @@ type UnderlaySocket interface {
 	WaitForDialIn() (*snet.UDPAddr, error)
 	WaitForDialInWithContext(ctx context.Context) (*snet.UDPAddr, error)
 	WaitForIncomingConn() (packets.UDPConn, error)
+	WaitForIncomingConnWithContext(ctx context.Context) (packets.UDPConn, error)
 	Dial(remote snet.UDPAddr, path snet.Path, options DialOptions, i int) (packets.UDPConn, error)
 	DialAll(remote snet.UDPAddr, path []pathselection.PathQuality, options DialOptions) ([]packets.UDPConn, error)
 	CloseAll() []error