[tor-commits] [snowflake/master] Remove support for the base64 WebSocket subprotocol.

[dcf at torproject.org]

commit 15963688c202df4d0c81a27bccdaefcfe22b5963
Author: David Fifield <david at bamsoftware.com>
Date:   Wed Jan 18 20:00:59 2017 -0800

    Remove support for the base64 WebSocket subprotocol.
    
    This was only needed for very very old Firefox before WebSockets were
    properly standardized.
---
 server/server.go | 49 +++++++++----------------------------------------
 1 file changed, 9 insertions(+), 40 deletions(-)

diff --git a/server/server.go b/server/server.go
index 5002e4e..5e63b7e 100644
--- a/server/server.go
+++ b/server/server.go
@@ -10,7 +10,6 @@ package main
 
 import (
 	"crypto/tls"
-	"encoding/base64"
 	"errors"
 	"flag"
 	"fmt"
@@ -31,8 +30,7 @@ import (
 const ptMethodName = "snowflake"
 const requestTimeout = 10 * time.Second
 
-// "4/3+1" accounts for possible base64 encoding.
-const maxMessageSize = 64*1024*4/3 + 1
+const maxMessageSize = 64*1024
 
 var ptInfo pt.ServerInfo
 
@@ -50,11 +48,9 @@ func usage() {
 }
 
 // An abstraction that makes an underlying WebSocket connection look like an
-// io.ReadWriteCloser. It internally takes care of things like base64 encoding
-// and decoding.
+// io.ReadWriteCloser.
 type webSocketConn struct {
 	Ws         *websocket.WebSocket
-	Base64     bool
 	messageBuf []byte
 }
 
@@ -70,25 +66,11 @@ func (conn *webSocketConn) Read(b []byte) (n int, err error) {
 			err = io.EOF
 			return
 		}
-		if conn.Base64 {
-			if m.Opcode != 1 {
-				err = errors.New(fmt.Sprintf("got non-text opcode %d with the base64 subprotocol", m.Opcode))
-				return
-			}
-			conn.messageBuf = make([]byte, base64.StdEncoding.DecodedLen(len(m.Payload)))
-			var num int
-			num, err = base64.StdEncoding.Decode(conn.messageBuf, m.Payload)
-			if err != nil {
-				return
-			}
-			conn.messageBuf = conn.messageBuf[:num]
-		} else {
-			if m.Opcode != 2 {
-				err = errors.New(fmt.Sprintf("got non-binary opcode %d with no subprotocol", m.Opcode))
-				return
-			}
-			conn.messageBuf = m.Payload
+		if m.Opcode != 2 {
+			err = errors.New(fmt.Sprintf("got non-binary opcode %d", m.Opcode))
+			return
 		}
+		conn.messageBuf = m.Payload
 	}
 
 	n = copy(b, conn.messageBuf)
@@ -98,20 +80,9 @@ func (conn *webSocketConn) Read(b []byte) (n int, err error) {
 }
 
 // Implements io.Writer.
-func (conn *webSocketConn) Write(b []byte) (n int, err error) {
-	if conn.Base64 {
-		buf := make([]byte, base64.StdEncoding.EncodedLen(len(b)))
-		base64.StdEncoding.Encode(buf, b)
-		err = conn.Ws.WriteMessage(1, buf)
-		if err != nil {
-			return
-		}
-		n = len(b)
-	} else {
-		err = conn.Ws.WriteMessage(2, b)
-		n = len(b)
-	}
-	return
+func (conn *webSocketConn) Write(b []byte) (int, error) {
+	err := conn.Ws.WriteMessage(2, b)
+	return len(b), err
 }
 
 // Implements io.Closer.
@@ -125,7 +96,6 @@ func (conn *webSocketConn) Close() error {
 func newWebSocketConn(ws *websocket.WebSocket) webSocketConn {
 	var conn webSocketConn
 	conn.Ws = ws
-	conn.Base64 = (ws.Subprotocol == "base64")
 	return conn
 }
 
@@ -233,7 +203,6 @@ func startServer(ln net.Listener) (net.Listener, error) {
 	go func() {
 		defer ln.Close()
 		var config websocket.Config
-		config.Subprotocols = []string{"base64"}
 		config.MaxMessageSize = maxMessageSize
 		s := &http.Server{
 			Handler:     config.Handler(webSocketHandler),