package telebit import ( "context" "fmt" "io" "net" "net/http" "os" "strings" "git.rootprojects.org/root/telebit/dbg" ) // A Listener transforms a multiplexed websocket connection into individual net.Conn-like connections. type Listener struct { //wsconn *websocket.Conn tun net.Conn incoming chan *Conn close chan struct{} encoder *Encoder chunksParsed int bytesRead int conns map[string]net.Conn //conns map[string]*Conn } // Listen creates a new Listener and sets it up to receive and distribute connections. func Listen(tun net.Conn) *Listener { ctx := context.TODO() // Feed the socket into the Encoder and Decoder listener := &Listener{ tun: tun, incoming: make(chan *Conn, 1), // buffer ever so slightly close: make(chan struct{}), encoder: NewEncoder(ctx, tun), conns: map[string]net.Conn{}, //conns: map[string]*Conn{}, } // TODO perhaps the wrapper should have a mutex // rather than having a goroutine in the encoder go func() { err := listener.encoder.Run() fmt.Printf("encoder stopped entirely: %q", err) listener.Close() }() // Decode the stream as it comes in decoder := NewDecoder(tun) go func() { // TODO pass error to Accept() // (this listener is also a telebit.Router) err := decoder.Decode(listener) // The listener itself must be closed explicitly because // there's an encoder with a callback between the websocket // and the multiplexer, so it doesn't know to stop listening otherwise _ = listener.Close() fmt.Printf("the main stream is done: %q\n", err) }() return listener } // ListenAndServe listens on a websocket and handles the incomming net.Conn-like connections with a Handler func ListenAndServe(tun net.Conn, mux Handler) error { listener := Listen(tun) return Serve(listener, mux) } // Serve Accept()s connections which have already been unwrapped and serves them with the given Handler func Serve(listener net.Listener, mux Handler) error { for { client, err := listener.Accept() if nil != err { return err } go func() { // nil means being handled // non-nil means handled // io.EOF means handled with success if err := mux.Serve(client); nil != err { if io.EOF != err && io.ErrClosedPipe != err && !strings.Contains(err.Error(), errNetClosing) { fmt.Printf("client could not be served: %q\n", err.Error()) } fmt.Printf("closing original client: %s\n", err) client.Close() } }() } } // Accept returns a tunneled network connection func (l *Listener) Accept() (net.Conn, error) { select { case rconn, ok := <-l.incoming: if ok { return rconn, nil } return nil, io.EOF case <-l.close: return nil, http.ErrServerClosed } } // Close stops accepting new connections and closes the underlying websocket. // TODO return errors. func (l *Listener) Close() error { l.tun.Close() close(l.incoming) l.close <- struct{}{} return nil } func (l *Listener) Addr() net.Addr { return l.tun.LocalAddr() } // RouteBytes receives address information and a buffer and creates or re-uses a pipe that can be Accept()ed. func (l *Listener) RouteBytes(srcAddr, dstAddr Addr, b []byte) { // TODO use context to be able to cancel many at once? l.chunksParsed++ src := &srcAddr dst := &dstAddr pipe := l.getPipe(src, dst, len(b)) //fmt.Printf("%s\n", b) // handle errors before data writes because I don't // remember where the error message goes if "error" == string(dst.scheme) { pipe.Close() delete(l.conns, src.String()) fmt.Printf("a stream errored remotely: %v\n", src) } // write data, if any if len(b) > 0 { l.bytesRead += len(b) pipe.Write(b) } // EOF, if needed if "end" == string(dst.scheme) { if dbg.Debug { fmt.Fprintf(os.Stderr, "[debug] end\n") } pipe.Close() delete(l.conns, src.String()) } } func (l *Listener) getPipe(src, dst *Addr, count int) net.Conn { connID := src.String() pipe, ok := l.conns[connID] // Pipe exists if ok { return pipe } fmt.Printf("New client (%d byte hello)\n\tfrom %#v\n\tto %#v:\n", count, src, dst) // Create pipe rawPipe, pipe := net.Pipe() newconn := &Conn{ //updated: time.Now(), relaySourceAddr: *dst, relayTargetAddr: *src, relay: rawPipe, } l.conns[connID] = pipe l.incoming <- newconn // Handle encoding go func() { // TODO handle err err := l.encoder.Encode(pipe, *src, *dst) // the error may be EOF or ErrServerClosed or ErrGoingAwawy or some such // or it might be an actual error // In any case, we'll just close it all newconn.Close() pipe.Close() if nil != err { fmt.Fprintf(os.Stderr, "[debug] [ln-pipe] encode stream ended:\n%+v\n%+v\n%q\n", *src, *dst, err) } else { fmt.Fprintf(os.Stderr, "[debug] [ln-pipe] encode stream ended gracefully:\n%+v\n%+v\n", *src, *dst) } }() return pipe }