This commit modifies the way polling is done on TLS sockets.

Because of the buffering the TLS layer does, polling is unreliable. If poll is
called while there is data waiting to be read in the TLS layer but not at the
network layer, the messaging processing engine will not proceed until something
else writes data to the socket, which may not occur. This change modifies the
logic around TLS sockets to only poll after a failed read on a non-blocking
socket. This way we know that there is no data waiting to be read from the
buffering layer.

(closes issue #19182)
Reported by: st
Patches:
      ssl-poll-fix3.diff uploaded by mnicholson (license 96)
Tested by: mnicholson


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.2@320179 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -2954,7 +2954,7 @@ static int sip_check_authtimeout(time_t start)
 */
 static void *_sip_tcp_helper_thread(struct sip_pvt *pvt, struct ast_tcptls_session_instance *tcptls_session) 
 {
-	int res, cl, timeout = -1, authenticated = 0, flags;
+	int res, cl, timeout = -1, authenticated = 0, flags, after_poll = 0, need_poll = 1;
 	time_t start;
 	struct sip_request req = { 0, } , reqcpy = { 0, };
 	struct sip_threadinfo *me = NULL;
@@ -3065,6 +3065,7 @@ static void *_sip_tcp_helper_thread(struct sip_pvt *pvt, struct ast_tcptls_sessi
 		/* handle the socket event, check for both reads from the socket fd,
 		 * and writes from alert_pipe fd */
 		if (fds[0].revents) { /* there is data on the socket to be read */
+			after_poll = 1;
 
 			fds[0].revents = 0;
 
@@ -3105,22 +3106,32 @@ static void *_sip_tcp_helper_thread(struct sip_pvt *pvt, struct ast_tcptls_sessi
 					timeout = -1;
 				}
 
-				res = ast_wait_for_input(tcptls_session->fd, timeout);
-				if (res < 0) {
-					ast_debug(2, "SIP %s server :: ast_wait_for_input returned %d\n", tcptls_session->ssl ? "SSL": "TCP", res);
-					goto cleanup;
-				} else if (res == 0) {
-					/* timeout */
-					ast_debug(2, "SIP %s server timed out\n", tcptls_session->ssl ? "SSL": "TCP");
-					goto cleanup;
+				if (!tcptls_session->ssl || need_poll) {
+					need_poll = 0;
+					after_poll = 1;
+					res = ast_wait_for_input(tcptls_session->fd, timeout);
+					if (res < 0) {
+						ast_debug(2, "SIP %s server :: ast_wait_for_input returned %d\n", tcptls_session->ssl ? "SSL": "TCP", res);
+						goto cleanup;
+					} else if (res == 0) {
+						/* timeout */
+						ast_debug(2, "SIP %s server timed out\n", tcptls_session->ssl ? "SSL": "TCP");
+						goto cleanup;
+					}
 				}
 
 				ast_mutex_lock(&tcptls_session->lock);
 				if (!fgets(buf, sizeof(buf), tcptls_session->f)) {
 					ast_mutex_unlock(&tcptls_session->lock);
-					goto cleanup;
+					if (after_poll) {
+						goto cleanup;
+					} else {
+						need_poll = 1;
+						continue;
+					}
 				}
 				ast_mutex_unlock(&tcptls_session->lock);
+				after_poll = 0;
 				if (me->stop)
 					 goto cleanup;
 				ast_str_append(&req.data, 0, "%s", buf);
@@ -3138,30 +3149,38 @@ static void *_sip_tcp_helper_thread(struct sip_pvt *pvt, struct ast_tcptls_sessi
 						}
 
 						if (timeout == 0) {
-							ast_debug(2, "SIP %s server timed out", tcptls_session->ssl ? "SSL": "TCP");
+							ast_debug(2, "SIP %s server timed out\n", tcptls_session->ssl ? "SSL": "TCP");
 							goto cleanup;
 						}
 					} else {
 						timeout = -1;
 					}
 
-					res = ast_wait_for_input(tcptls_session->fd, timeout);
-					if (res < 0) {
-						ast_debug(2, "SIP %s server :: ast_wait_for_input returned %d\n", tcptls_session->ssl ? "SSL": "TCP", res);
-						goto cleanup;
-					} else if (res == 0) {
-						/* timeout */
-						ast_debug(2, "SIP %s server timed out", tcptls_session->ssl ? "SSL": "TCP");
-						goto cleanup;
+					if (!tcptls_session->ssl || need_poll) {
+						res = ast_wait_for_input(tcptls_session->fd, timeout);
+						if (res < 0) {
+							ast_debug(2, "SIP %s server :: ast_wait_for_input returned %d\n", tcptls_session->ssl ? "SSL": "TCP", res);
+							goto cleanup;
+						} else if (res == 0) {
+							/* timeout */
+							ast_debug(2, "SIP %s server timed out\n", tcptls_session->ssl ? "SSL": "TCP");
+							goto cleanup;
+						}
 					}
 
 					ast_mutex_lock(&tcptls_session->lock);
 					if (!(bytes_read = fread(buf, 1, MIN(sizeof(buf) - 1, cl), tcptls_session->f))) {
 						ast_mutex_unlock(&tcptls_session->lock);
-						goto cleanup;
+						if (after_poll) {
+							goto cleanup;
+						} else {
+							need_poll = 1;
+							continue;
+						}
 					}
 					buf[bytes_read] = '\0';
 					ast_mutex_unlock(&tcptls_session->lock);
+					after_poll = 0;
 					if (me->stop)
 						goto cleanup;
 					cl -= strlen(buf);