[svn-commits] dlee: branch 11 r432236 - /branches/11/res/res_http_websocket.c

[SVN commits to the Digium repositories]

Author: dlee
Date: Wed Feb 25 14:43:16 2015
New Revision: 432236

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=432236
Log:
Increase WebSocket frame size and improve large read handling

Some WebSocket applications, like [chan_respoke][], require a larger
frame size than the default 8k; this patch bumps the default to 16k.
This patch also fixes some problems exacerbated by large frames.

The sanity counter was decremented on every fread attempt in
ws_safe_read(), regardless of whether data was read from the socket or
not. For large frames, this could result in loss of sanity prior to
reading the entire frame. (16k frame / 1448 bytes per segment = 12
segments).

This patch changes the sanity counter so that it only decrements when
fread() doesn't read any bytes. This more closely matches the original
intention of ws_safe_read(), given that the error message is
"Websocket seems unresponsive".

This patch also properly logs EOF conditions, so disconnects are no
longer confused with unresponsive connections.

 [chan_respoke]: https://github.com/respoke/chan_respoke

Modified:
    branches/11/res/res_http_websocket.c

Modified: branches/11/res/res_http_websocket.c
URL: http://svnview.digium.com/svn/asterisk/branches/11/res/res_http_websocket.c?view=diff&rev=432236&r1=432235&r2=432236
==============================================================================
--- branches/11/res/res_http_websocket.c (original)
+++ branches/11/res/res_http_websocket.c Wed Feb 25 14:43:16 2015
@@ -48,7 +48,7 @@
 #define MAX_PROTOCOL_BUCKETS 7
 
 /*! \brief Size of the pre-determined buffer for WebSocket frames */
-#define MAXIMUM_FRAME_SIZE 8192
+#define MAXIMUM_FRAME_SIZE 16384
 
 /*! \brief Default reconstruction size for multi-frame payload reconstruction. If exceeded the next frame will start a
  *         payload.
@@ -361,18 +361,35 @@
  */
 static inline int ws_safe_read(struct ast_websocket *session, char *buf, int len, enum ast_websocket_opcode *opcode)
 {
-	int sanity;
 	size_t rlen;
 	int xlen = len;
 	char *rbuf = buf;
-	for (sanity = 10; sanity; sanity--) {
+	int sanity = 10;
+
+	for (;;) {
 		clearerr(session->f);
 		rlen = fread(rbuf, 1, xlen, session->f);
-		if (!rlen && ferror(session->f) && errno != EAGAIN) {
-			ast_log(LOG_ERROR, "Error reading from web socket: %s\n", strerror(errno));
-			*opcode = AST_WEBSOCKET_OPCODE_CLOSE;
-			session->closing = 1;
-			return -1;
+		if (!rlen) {
+			if (feof(session->f)) {
+				ast_log(LOG_WARNING, "Web socket closed abruptly\n");
+				*opcode = AST_WEBSOCKET_OPCODE_CLOSE;
+				session->closing = 1;
+				return -1;
+			}
+
+			if (ferror(session->f) && errno != EAGAIN) {
+				ast_log(LOG_ERROR, "Error reading from web socket: %s\n", strerror(errno));
+				*opcode = AST_WEBSOCKET_OPCODE_CLOSE;
+				session->closing = 1;
+				return -1;
+			}
+
+			if (!--sanity) {
+				ast_log(LOG_WARNING, "Websocket seems unresponsive, disconnecting ...\n");
+				*opcode = AST_WEBSOCKET_OPCODE_CLOSE;
+				session->closing = 1;
+				return -1;
+			}
 		}
 		xlen = xlen - rlen;
 		rbuf = rbuf + rlen;
@@ -385,12 +402,6 @@
 			session->closing = 1;
 			return -1;
 		}
-	}
-	if (!sanity) {
-		ast_log(LOG_WARNING, "Websocket seems unresponsive, disconnecting ...\n");
-		*opcode = AST_WEBSOCKET_OPCODE_CLOSE;
-		session->closing = 1;
-		return -1;
 	}
 	return 0;
 }