Use a single socket for relaying
This commit is contained in:
AudriusButkevicius
302
listener.go
Normal file
302
listener.go
Normal file
@@ -0,0 +1,302 @@
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// Copyright (C) 2015 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
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package main
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import (
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"crypto/tls"
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"log"
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"net"
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"sync"
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"sync/atomic"
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"time"
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syncthingprotocol "github.com/syncthing/protocol"
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"github.com/syncthing/syncthing/lib/tlsutil"
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"github.com/syncthing/relaysrv/protocol"
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)
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var (
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outboxesMut = sync.RWMutex{}
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outboxes = make(map[syncthingprotocol.DeviceID]chan interface{})
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numConnections int64
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)
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func listener(addr string, config *tls.Config) {
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tcpListener, err := net.Listen("tcp", addr)
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if err != nil {
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log.Fatalln(err)
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}
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listener := tlsutil.DowngradingListener{tcpListener, nil}
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for {
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conn, isTLS, err := listener.AcceptNoWrap()
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if err != nil {
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if debug {
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log.Println(err)
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}
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continue
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}
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setTCPOptions(conn)
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if debug {
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log.Println("Listener accepted connection from", conn.RemoteAddr(), "tls", isTLS)
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}
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if isTLS {
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go protocolConnectionHandler(conn, config)
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} else {
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go sessionConnectionHandler(conn)
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}
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}
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}
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func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
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conn := tls.Server(tcpConn, config)
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err := conn.Handshake()
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if err != nil {
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if debug {
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log.Println("Protocol connection TLS handshake:", conn.RemoteAddr(), err)
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}
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conn.Close()
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return
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}
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state := conn.ConnectionState()
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if (!state.NegotiatedProtocolIsMutual || state.NegotiatedProtocol != protocol.ProtocolName) && debug {
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log.Println("Protocol negotiation error")
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}
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certs := state.PeerCertificates
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if len(certs) != 1 {
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if debug {
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log.Println("Certificate list error")
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}
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conn.Close()
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return
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}
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id := syncthingprotocol.NewDeviceID(certs[0].Raw)
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messages := make(chan interface{})
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errors := make(chan error, 1)
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outbox := make(chan interface{})
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// Read messages from the connection and send them on the messages
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// channel. When there is an error, send it on the error channel and
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// return. Applies also when the connection gets closed, so the pattern
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// below is to close the connection on error, then wait for the error
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// signal from messageReader to exit.
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go messageReader(conn, messages, errors)
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pingTicker := time.NewTicker(pingInterval)
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timeoutTicker := time.NewTimer(networkTimeout)
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joined := false
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for {
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select {
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case message := <-messages:
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timeoutTicker.Reset(networkTimeout)
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if debug {
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log.Printf("Message %T from %s", message, id)
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}
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switch msg := message.(type) {
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case protocol.JoinRelayRequest:
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outboxesMut.RLock()
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_, ok := outboxes[id]
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outboxesMut.RUnlock()
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if ok {
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protocol.WriteMessage(conn, protocol.ResponseAlreadyConnected)
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if debug {
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log.Println("Already have a peer with the same ID", id, conn.RemoteAddr())
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}
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conn.Close()
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continue
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}
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outboxesMut.Lock()
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outboxes[id] = outbox
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outboxesMut.Unlock()
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joined = true
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protocol.WriteMessage(conn, protocol.ResponseSuccess)
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case protocol.ConnectRequest:
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requestedPeer := syncthingprotocol.DeviceIDFromBytes(msg.ID)
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outboxesMut.RLock()
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peerOutbox, ok := outboxes[requestedPeer]
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outboxesMut.RUnlock()
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if !ok {
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if debug {
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log.Println(id, "is looking for", requestedPeer, "which does not exist")
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}
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protocol.WriteMessage(conn, protocol.ResponseNotFound)
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conn.Close()
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continue
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}
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ses := newSession(sessionLimiter, globalLimiter)
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go ses.Serve()
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clientInvitation := ses.GetClientInvitationMessage(requestedPeer)
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serverInvitation := ses.GetServerInvitationMessage(id)
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if err := protocol.WriteMessage(conn, clientInvitation); err != nil {
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if debug {
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log.Printf("Error sending invitation from %s to client: %s", id, err)
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}
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conn.Close()
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continue
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}
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peerOutbox <- serverInvitation
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if debug {
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log.Println("Sent invitation from", id, "to", requestedPeer)
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}
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conn.Close()
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case protocol.Pong:
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// Nothing
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default:
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if debug {
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log.Printf("Unknown message %s: %T", id, message)
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}
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protocol.WriteMessage(conn, protocol.ResponseUnexpectedMessage)
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conn.Close()
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}
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case err := <-errors:
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if debug {
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log.Printf("Closing connection %s: %s", id, err)
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}
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close(outbox)
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// Potentially closing a second time.
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conn.Close()
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// Only delete the outbox if the client is joined, as it might be
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// a lookup request coming from the same client.
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if joined {
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outboxesMut.Lock()
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delete(outboxes, id)
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outboxesMut.Unlock()
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}
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return
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case <-pingTicker.C:
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if !joined {
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if debug {
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log.Println(id, "didn't join within", pingInterval)
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}
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conn.Close()
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continue
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}
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if err := protocol.WriteMessage(conn, protocol.Ping{}); err != nil {
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if debug {
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log.Println(id, err)
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}
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conn.Close()
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}
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case <-timeoutTicker.C:
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// We should receive a error from the reader loop, which will cause
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// us to quit this loop.
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if debug {
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log.Printf("%s timed out", id)
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}
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conn.Close()
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case msg := <-outbox:
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if debug {
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log.Printf("Sending message %T to %s", msg, id)
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}
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if err := protocol.WriteMessage(conn, msg); err != nil {
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if debug {
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log.Println(id, err)
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}
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conn.Close()
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}
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}
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}
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}
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func sessionConnectionHandler(conn net.Conn) {
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if err := conn.SetDeadline(time.Now().Add(messageTimeout)); err != nil {
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if debug {
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log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
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}
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return
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}
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message, err := protocol.ReadMessage(conn)
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if err != nil {
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return
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}
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switch msg := message.(type) {
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case protocol.JoinSessionRequest:
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ses := findSession(string(msg.Key))
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if debug {
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log.Println(conn.RemoteAddr(), "session lookup", ses)
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}
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if ses == nil {
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protocol.WriteMessage(conn, protocol.ResponseNotFound)
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conn.Close()
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return
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}
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if !ses.AddConnection(conn) {
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if debug {
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log.Println("Failed to add", conn.RemoteAddr(), "to session", ses)
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}
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protocol.WriteMessage(conn, protocol.ResponseAlreadyConnected)
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conn.Close()
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return
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}
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if err := protocol.WriteMessage(conn, protocol.ResponseSuccess); err != nil {
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if debug {
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log.Println("Failed to send session join response to ", conn.RemoteAddr(), "for", ses)
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}
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return
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}
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if err := conn.SetDeadline(time.Time{}); err != nil {
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if debug {
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log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
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}
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conn.Close()
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return
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}
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default:
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if debug {
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log.Println("Unexpected message from", conn.RemoteAddr(), message)
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}
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protocol.WriteMessage(conn, protocol.ResponseUnexpectedMessage)
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conn.Close()
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}
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}
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func messageReader(conn net.Conn, messages chan<- interface{}, errors chan<- error) {
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atomic.AddInt64(&numConnections, 1)
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defer atomic.AddInt64(&numConnections, -1)
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for {
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msg, err := protocol.ReadMessage(conn)
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if err != nil {
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errors <- err
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return
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}
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messages <- msg
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}
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}
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