func sessionConnectionHandler(conn net.Conn) {
if err := conn.SetDeadline(time.Now().Add(messageTimeout)); err != nil {
if debug {
log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
}
return
}
message, err := protocol.ReadMessage(conn)
if err != nil {
return
}
switch msg := message.(type) {
case protocol.JoinSessionRequest:
ses := findSession(string(msg.Key))
if debug {
log.Println(conn.RemoteAddr(), "session lookup", ses, hex.EncodeToString(msg.Key)[:5])
}
if ses == nil {
protocol.WriteMessage(conn, protocol.ResponseNotFound)
conn.Close()
return
}
if !ses.AddConnection(conn) {
if debug {
log.Println("Failed to add", conn.RemoteAddr(), "to session", ses)
}
protocol.WriteMessage(conn, protocol.ResponseAlreadyConnected)
conn.Close()
return
}
if err := protocol.WriteMessage(conn, protocol.ResponseSuccess); err != nil {
if debug {
log.Println("Failed to send session join response to ", conn.RemoteAddr(), "for", ses)
}
return
}
if err := conn.SetDeadline(time.Time{}); err != nil {
if debug {
log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
}
conn.Close()
return
}
default:
if debug {
log.Println("Unexpected message from", conn.RemoteAddr(), message)
}
protocol.WriteMessage(conn, protocol.ResponseUnexpectedMessage)
conn.Close()
}
}
func (c *staticClient) join() error {
if err := protocol.WriteMessage(c.conn, protocol.JoinRelayRequest{}); err != nil {
return err
}
message, err := protocol.ReadMessage(c.conn)
if err != nil {
return err
}
switch msg := message.(type) {
case protocol.Response:
if msg.Code != 0 {
return fmt.Errorf("Incorrect response code %d: %s", msg.Code, msg.Message)
}
case protocol.RelayFull:
return fmt.Errorf("relay full")
default:
return fmt.Errorf("protocol error: expecting response got %v", msg)
}
return nil
}
func JoinSession(invitation protocol.SessionInvitation) (net.Conn, error) {
addr := net.JoinHostPort(net.IP(invitation.Address).String(), strconv.Itoa(int(invitation.Port)))
conn, err := net.Dial("tcp", addr)
if err != nil {
return nil, err
}
request := protocol.JoinSessionRequest{
Key: invitation.Key,
}
conn.SetDeadline(time.Now().Add(10 * time.Second))
err = protocol.WriteMessage(conn, request)
if err != nil {
return nil, err
}
message, err := protocol.ReadMessage(conn)
if err != nil {
return nil, err
}
conn.SetDeadline(time.Time{})
switch msg := message.(type) {
case protocol.Response:
if msg.Code != 0 {
return nil, fmt.Errorf("Incorrect response code %d: %s", msg.Code, msg.Message)
}
return conn, nil
default:
return nil, fmt.Errorf("protocol error: expecting response got %v", msg)
}
}
func GetInvitationFromRelay(uri *url.URL, id syncthingprotocol.DeviceID, certs []tls.Certificate) (protocol.SessionInvitation, error) {
if uri.Scheme != "relay" {
return protocol.SessionInvitation{}, fmt.Errorf("Unsupported relay scheme: %v", uri.Scheme)
}
rconn, err := dialer.Dial("tcp", uri.Host)
if err != nil {
return protocol.SessionInvitation{}, err
}
conn := tls.Client(rconn, configForCerts(certs))
conn.SetDeadline(time.Now().Add(10 * time.Second))
if err := performHandshakeAndValidation(conn, uri); err != nil {
return protocol.SessionInvitation{}, err
}
defer conn.Close()
request := protocol.ConnectRequest{
ID: id[:],
}
if err := protocol.WriteMessage(conn, request); err != nil {
return protocol.SessionInvitation{}, err
}
message, err := protocol.ReadMessage(conn)
if err != nil {
return protocol.SessionInvitation{}, err
}
switch msg := message.(type) {
case protocol.Response:
return protocol.SessionInvitation{}, fmt.Errorf("Incorrect response code %d: %s", msg.Code, msg.Message)
case protocol.SessionInvitation:
l.Debugln("Received invitation", msg, "via", conn.LocalAddr())
ip := net.IP(msg.Address)
if len(ip) == 0 || ip.IsUnspecified() {
msg.Address = conn.RemoteAddr().(*net.TCPAddr).IP[:]
}
return msg, nil
default:
return protocol.SessionInvitation{}, fmt.Errorf("protocol error: unexpected message %v", msg)
}
}
func (c *ProtocolClient) Serve() {
c.stop = make(chan struct{})
c.stopped = make(chan struct{})
defer close(c.stopped)
if err := c.connect(); err != nil {
l.Debugln("Relay connect:", err)
return
}
l.Debugln(c, "connected", c.conn.RemoteAddr())
if err := c.join(); err != nil {
c.conn.Close()
l.Infoln("Relay join:", err)
return
}
if err := c.conn.SetDeadline(time.Time{}); err != nil {
l.Infoln("Relay set deadline:", err)
return
}
l.Debugln(c, "joined", c.conn.RemoteAddr(), "via", c.conn.LocalAddr())
defer c.cleanup()
c.mut.Lock()
c.connected = true
c.mut.Unlock()
messages := make(chan interface{})
errors := make(chan error, 1)
go messageReader(c.conn, messages, errors)
timeout := time.NewTimer(c.timeout)
for {
select {
case message := <-messages:
timeout.Reset(c.timeout)
l.Debugf("%s received message %T", c, message)
switch msg := message.(type) {
case protocol.Ping:
if err := protocol.WriteMessage(c.conn, protocol.Pong{}); err != nil {
l.Infoln("Relay write:", err)
return
}
l.Debugln(c, "sent pong")
case protocol.SessionInvitation:
ip := net.IP(msg.Address)
if len(ip) == 0 || ip.IsUnspecified() {
msg.Address = c.conn.RemoteAddr().(*net.TCPAddr).IP[:]
}
c.Invitations <- msg
default:
l.Infoln("Relay: protocol error: unexpected message %v", msg)
return
}
case <-c.stop:
l.Debugln(c, "stopping")
return
case err := <-errors:
l.Infoln("Relay received:", err)
return
case <-timeout.C:
l.Debugln(c, "timed out")
return
}
}
}
func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
conn := tls.Server(tcpConn, config)
err := conn.Handshake()
if err != nil {
if debug {
log.Println("Protocol connection TLS handshake:", conn.RemoteAddr(), err)
}
conn.Close()
return
}
state := conn.ConnectionState()
if (!state.NegotiatedProtocolIsMutual || state.NegotiatedProtocol != protocol.ProtocolName) && debug {
log.Println("Protocol negotiation error")
}
certs := state.PeerCertificates
if len(certs) != 1 {
if debug {
log.Println("Certificate list error")
}
conn.Close()
return
}
id := syncthingprotocol.NewDeviceID(certs[0].Raw)
messages := make(chan interface{})
errors := make(chan error, 1)
outbox := make(chan interface{})
// Read messages from the connection and send them on the messages
// channel. When there is an error, send it on the error channel and
// return. Applies also when the connection gets closed, so the pattern
// below is to close the connection on error, then wait for the error
// signal from messageReader to exit.
go messageReader(conn, messages, errors)
pingTicker := time.NewTicker(pingInterval)
timeoutTicker := time.NewTimer(networkTimeout)
joined := false
for {
select {
case message := <-messages:
timeoutTicker.Reset(networkTimeout)
if debug {
log.Printf("Message %T from %s", message, id)
}
switch msg := message.(type) {
case protocol.JoinRelayRequest:
if atomic.LoadInt32(&overLimit) > 0 {
protocol.WriteMessage(conn, protocol.RelayFull{})
if debug {
log.Println("Refusing join request from", id, "due to being over limits")
}
conn.Close()
limitCheckTimer.Reset(time.Second)
continue
}
outboxesMut.RLock()
_, ok := outboxes[id]
outboxesMut.RUnlock()
if ok {
protocol.WriteMessage(conn, protocol.ResponseAlreadyConnected)
if debug {
log.Println("Already have a peer with the same ID", id, conn.RemoteAddr())
}
conn.Close()
continue
}
outboxesMut.Lock()
outboxes[id] = outbox
outboxesMut.Unlock()
joined = true
protocol.WriteMessage(conn, protocol.ResponseSuccess)
case protocol.ConnectRequest:
requestedPeer := syncthingprotocol.DeviceIDFromBytes(msg.ID)
outboxesMut.RLock()
peerOutbox, ok := outboxes[requestedPeer]
outboxesMut.RUnlock()
if !ok {
if debug {
log.Println(id, "is looking for", requestedPeer, "which does not exist")
}
protocol.WriteMessage(conn, protocol.ResponseNotFound)
conn.Close()
continue
}
// requestedPeer is the server, id is the client
ses := newSession(requestedPeer, id, sessionLimiter, globalLimiter)
go ses.Serve()
clientInvitation := ses.GetClientInvitationMessage()
serverInvitation := ses.GetServerInvitationMessage()
if err := protocol.WriteMessage(conn, clientInvitation); err != nil {
if debug {
log.Printf("Error sending invitation from %s to client: %s", id, err)
}
conn.Close()
continue
}
peerOutbox <- serverInvitation
if debug {
log.Println("Sent invitation from", id, "to", requestedPeer)
}
conn.Close()
case protocol.Ping:
if err := protocol.WriteMessage(conn, protocol.Pong{}); err != nil {
if debug {
log.Println("Error writing pong:", err)
}
conn.Close()
continue
}
case protocol.Pong:
// Nothing
default:
if debug {
log.Printf("Unknown message %s: %T", id, message)
}
protocol.WriteMessage(conn, protocol.ResponseUnexpectedMessage)
conn.Close()
}
case err := <-errors:
if debug {
log.Printf("Closing connection %s: %s", id, err)
}
close(outbox)
// Potentially closing a second time.
conn.Close()
if joined {
// Only delete the outbox if the client is joined, as it might be
// a lookup request coming from the same client.
outboxesMut.Lock()
delete(outboxes, id)
outboxesMut.Unlock()
// Also, kill all sessions related to this node, as it probably
// went offline. This is for the other end to realize the client
// is no longer there faster. This also helps resolve
// 'already connected' errors when one of the sides is
// restarting, and connecting to the other peer before the other
// peer even realised that the node has gone away.
dropSessions(id)
}
return
case <-pingTicker.C:
if !joined {
if debug {
log.Println(id, "didn't join within", pingInterval)
}
conn.Close()
continue
}
if err := protocol.WriteMessage(conn, protocol.Ping{}); err != nil {
if debug {
log.Println(id, err)
}
conn.Close()
}
if atomic.LoadInt32(&overLimit) > 0 && !hasSessions(id) {
if debug {
log.Println("Dropping", id, "as it has no sessions and we are over our limits")
}
protocol.WriteMessage(conn, protocol.RelayFull{})
conn.Close()
limitCheckTimer.Reset(time.Second)
}
case <-timeoutTicker.C:
// We should receive a error from the reader loop, which will cause
// us to quit this loop.
if debug {
log.Printf("%s timed out", id)
}
conn.Close()
case msg := <-outbox:
if msg == nil {
conn.Close()
return
}
if debug {
log.Printf("Sending message %T to %s", msg, id)
}
if err := protocol.WriteMessage(conn, msg); err != nil {
if debug {
log.Println(id, err)
}
conn.Close()
}
}
}
}
func (c *staticClient) Serve() {
c.stop = make(chan struct{})
c.stopped = make(chan struct{})
defer close(c.stopped)
if err := c.connect(); err != nil {
l.Infof("Could not connect to relay %s: %s", c.uri, err)
return
}
l.Debugln(c, "connected", c.conn.RemoteAddr())
if err := c.join(); err != nil {
c.conn.Close()
l.Infof("Could not join relay %s: %s", c.uri, err)
return
}
if err := c.conn.SetDeadline(time.Time{}); err != nil {
c.conn.Close()
l.Infoln("Relay set deadline:", err)
return
}
l.Infoln("Joined relay", c.uri)
c.mut.Lock()
c.connected = true
c.mut.Unlock()
messages := make(chan interface{})
errors := make(chan error, 1)
go messageReader(c.conn, messages, errors)
timeout := time.NewTimer(c.messageTimeout)
for {
select {
case message := <-messages:
timeout.Reset(c.messageTimeout)
l.Debugf("%s received message %T", c, message)
switch msg := message.(type) {
case protocol.Ping:
if err := protocol.WriteMessage(c.conn, protocol.Pong{}); err != nil {
l.Infoln("Relay write:", err)
c.disconnect()
} else {
l.Debugln(c, "sent pong")
}
case protocol.SessionInvitation:
ip := net.IP(msg.Address)
if len(ip) == 0 || ip.IsUnspecified() {
msg.Address = c.conn.RemoteAddr().(*net.TCPAddr).IP[:]
}
c.invitations <- msg
case protocol.RelayFull:
l.Infof("Disconnected from relay %s due to it becoming full.", c.uri)
c.disconnect()
default:
l.Infoln("Relay: protocol error: unexpected message %v", msg)
c.disconnect()
}
case <-c.stop:
l.Debugln(c, "stopping")
c.disconnect()
// We always exit via this branch of the select, to make sure the
// the reader routine exits.
case err := <-errors:
close(errors)
close(messages)
c.mut.Lock()
if c.connected {
c.conn.Close()
c.connected = false
l.Infof("Disconnecting from relay %s due to error: %s", c.uri, err)
}
if c.closeInvitationsOnFinish {
close(c.invitations)
c.invitations = make(chan protocol.SessionInvitation)
}
c.mut.Unlock()
return
case <-timeout.C:
l.Debugln(c, "timed out")
c.disconnect()
}
}
}