mirror of https://github.com/tailscale/tailscale/
cmd/derper, derp/derphttp: add websocket support
Updates #3157 Change-Id: I337a919a3b350bc7bd9af567b49c4d5d6616abdd Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>pull/3179/head
Brad Fitzpatrick
3 years ago
committed by
Brad Fitzpatrick
parent
0b62f26349
commit
505f844a43
@ -0,0 +1,52 @@
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// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"bufio"
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"expvar"
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"log"
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"net/http"
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"strings"
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"nhooyr.io/websocket"
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"tailscale.com/derp"
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"tailscale.com/derp/wsconn"
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)
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var counterWebSocketAccepts = expvar.NewInt("derp_websocket_accepts")
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// addWebSocketSupport returns a Handle wrapping base that adds WebSocket server support.
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func addWebSocketSupport(s *derp.Server, base http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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up := strings.ToLower(r.Header.Get("Upgrade"))
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// Very early versions of Tailscale set "Upgrade: WebSocket" but didn't actually
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// speak WebSockets (they still assumed DERP's binary framining). So to distinguish
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// clients that actually want WebSockets, look for an explicit "derp" subprotocol.
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if up != "websocket" || !strings.Contains(r.Header.Get("Sec-Websocket-Protocol"), "derp") {
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base.ServeHTTP(w, r)
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return
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}
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c, err := websocket.Accept(w, r, &websocket.AcceptOptions{
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Subprotocols: []string{"derp"},
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OriginPatterns: []string{"*"},
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})
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if err != nil {
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log.Printf("websocket.Accept: %v", err)
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return
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}
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defer c.Close(websocket.StatusInternalError, "closing")
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if c.Subprotocol() != "derp" {
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c.Close(websocket.StatusPolicyViolation, "client must speak the derp subprotocol")
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return
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}
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counterWebSocketAccepts.Add(1)
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wc := wsconn.New(c)
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brw := bufio.NewReadWriter(bufio.NewReader(wc), bufio.NewWriter(wc))
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s.Accept(wc, brw, r.RemoteAddr)
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})
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}
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@ -0,0 +1,33 @@
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// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build linux || js
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// +build linux js
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package derphttp
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import (
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"context"
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"log"
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"net"
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"nhooyr.io/websocket"
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"tailscale.com/derp/wsconn"
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)
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func init() {
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dialWebsocketFunc = dialWebsocket
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}
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func dialWebsocket(ctx context.Context, urlStr string) (net.Conn, error) {
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c, res, err := websocket.Dial(ctx, urlStr, &websocket.DialOptions{
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Subprotocols: []string{"derp"},
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})
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if err != nil {
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log.Printf("websocket Dial: %v, %+v", err, res)
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return nil, err
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}
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log.Printf("websocket: connected to %v", urlStr)
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return wsconn.New(c), nil
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}
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@ -0,0 +1,104 @@
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// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package wsconn contains an adapter type that turns
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// a websocket connection into a net.Conn.
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package wsconn
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import (
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"context"
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"net"
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"sync"
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"time"
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"nhooyr.io/websocket"
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)
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// New returns a net.Conn wrapper around c,
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// using c to send and receive binary messages with
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// chunks of bytes with no defined framing, effectively
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// discarding all WebSocket-level message framing.
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func New(c *websocket.Conn) net.Conn {
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return &websocketConn{c: c}
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}
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// websocketConn implements derp.Conn around a *websocket.Conn,
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// treating a websocket.Conn as a byte stream, ignoring the WebSocket
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// frame/message boundaries.
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type websocketConn struct {
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c *websocket.Conn
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// rextra are extra bytes owned by the reader.
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rextra []byte
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mu sync.Mutex
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rdeadline time.Time
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cancelRead context.CancelFunc
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}
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func (wc *websocketConn) LocalAddr() net.Addr { return addr{} }
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func (wc *websocketConn) RemoteAddr() net.Addr { return addr{} }
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type addr struct{}
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func (addr) Network() string { return "websocket" }
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func (addr) String() string { return "websocket" }
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func (wc *websocketConn) Read(p []byte) (n int, err error) {
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// Drain any leftover from previously.
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n = copy(p, wc.rextra)
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if n > 0 {
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wc.rextra = wc.rextra[n:]
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return n, nil
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}
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var ctx context.Context
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var cancel context.CancelFunc
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wc.mu.Lock()
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if dl := wc.rdeadline; !dl.IsZero() {
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ctx, cancel = context.WithDeadline(context.Background(), wc.rdeadline)
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} else {
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ctx, cancel = context.WithDeadline(context.Background(), time.Now().Add(30*24*time.Hour))
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wc.rdeadline = time.Time{}
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}
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wc.cancelRead = cancel
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wc.mu.Unlock()
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defer cancel()
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_, buf, err := wc.c.Read(ctx)
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n = copy(p, buf)
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wc.rextra = buf[n:]
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return n, err
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}
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func (wc *websocketConn) Write(p []byte) (n int, err error) {
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err = wc.c.Write(context.Background(), websocket.MessageBinary, p)
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if err != nil {
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return 0, err
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}
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return len(p), nil
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}
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func (wc *websocketConn) Close() error { return wc.c.Close(websocket.StatusNormalClosure, "close") }
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func (wc *websocketConn) SetDeadline(t time.Time) error {
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wc.SetReadDeadline(t)
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wc.SetWriteDeadline(t)
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return nil
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}
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func (wc *websocketConn) SetReadDeadline(t time.Time) error {
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wc.mu.Lock()
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defer wc.mu.Unlock()
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if !t.IsZero() && (wc.rdeadline.IsZero() || t.Before(wc.rdeadline)) && wc.cancelRead != nil {
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wc.cancelRead()
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}
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wc.rdeadline = t
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return nil
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}
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func (wc *websocketConn) SetWriteDeadline(t time.Time) error {
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return nil
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}
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