Added flag to increase time to wait for ws/wss handshake.

For long latency clients then may not be able to deliver the websocket
handshake before we fall back to regular the RFB protocol.

Now it is possible to set expect_ws_handshake=1 which will increase
the timeout to be rfbMaxClientWait or maxClientWait if set.

Author: sgh

libvncserver/websockets.c

@@ -80,8 +80,7 @@ Connection: Upgrade\r\n\
 Sec-WebSocket-Accept: %s\r\n\
 \r\n"
 
-#define WEBSOCKETS_CLIENT_CONNECT_WAIT_MS 100
-#define WEBSOCKETS_CLIENT_SEND_WAIT_MS 100
+#define WEBSOCKETS_CLIENT_CONNECT_WAIT_MS 500
 #define WEBSOCKETS_MAX_HANDSHAKE_LEN 4096
 
 #if defined(__linux__) && defined(NEED_TIMEVAL)
@@ -125,8 +124,14 @@ webSocketsCheck (rfbClientPtr cl)
     char bbuf[4], *scheme;
     int ret;
 
-    ret = rfbPeekExactTimeout(cl, bbuf, 4,
-                                   WEBSOCKETS_CLIENT_CONNECT_WAIT_MS);
+    /* If we expect the handshake - lets wait longer for it */
+    int timeout;
+    if (cl->screen->expect_ws_handshake)
+        timeout = cl->screen->maxClientWait ? cl->screen->maxClientWait : rfbMaxClientWait;
+    else
+        timeout = WEBSOCKETS_CLIENT_CONNECT_WAIT_MS;
+
+    ret = rfbPeekExactTimeout(cl, bbuf, 4, timeout);
     if ((ret < 0) && (errno == ETIMEDOUT)) {
       rfbLog("Normal socket connection\n");
       return TRUE;
@@ -144,7 +149,7 @@ webSocketsCheck (rfbClientPtr cl)
 	  rfbErr("webSocketsHandshake: rfbssl_init failed\n");
 	  return FALSE;
 	}
-	ret = rfbPeekExactTimeout(cl, bbuf, 4, WEBSOCKETS_CLIENT_CONNECT_WAIT_MS);
+	ret = rfbPeekExactTimeout(cl, bbuf, 4, timeout);
         scheme = "wss";
     } else {
         scheme = "ws";
@@ -189,8 +194,7 @@ webSocketsHandshake(rfbClientPtr cl, char *scheme)
     }
 
     while (len < WEBSOCKETS_MAX_HANDSHAKE_LEN-1) {
-        if ((n = rfbReadExactTimeout(cl, buf+len, 1,
-                                     WEBSOCKETS_CLIENT_SEND_WAIT_MS)) <= 0) {
+        if ((n = rfbReadExact(cl, buf+len, 1)) <= 0) {
             if ((n < 0) && (errno == ETIMEDOUT)) {
                 break;
             }

rfb/rfb.h

@@ -366,6 +366,9 @@ typedef struct _rfbScreenInfo
 #elif defined(LIBVNCSERVER_HAVE_WIN32THREADS)
     uintptr_t listener_thread;
 #endif
+
+    char expect_ws_handshake; /**< Set to 1 to wait longer for client ws or wss handshake */
+
 } rfbScreenInfo, *rfbScreenInfoPtr;