If an INFO request within a dialog is received with a content length of 0 simply send back a 200 OK. It is valid to do this and the remote side is probably using it to make sure the signalling is still alive.

(closes issue #5747)
Reported by: chandi
Patches:
      infofix-81430-1.patch uploaded by IgorG (license 20)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@88328 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -11003,7 +11003,12 @@ static void handle_request_info(struct sip_pvt *p, struct sip_request *req)
 			transmit_response(p, "403 Unauthorized", req);
 		}
 		return;
+	} else if (ast_strlen_zero(c = get_header(req, "Content-Length")) || !strcasecmp(c, "0")) {
+		/* This is probably just a packet making sure the signalling is still up, just send back a 200 OK */
+		transmit_response(p, "200 OK", req);
+		return;
 	}
+
 	/* Other type of INFO message, not really understood by Asterisk */
 	/* if (get_msg_text(buf, sizeof(buf), req)) { */