Don't process re-subscribes as new subscriptions.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@16804 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -6534,6 +6534,10 @@ static int cb_extensionstate(char *context, char* exten, int state, void *data)
 {
 	struct sip_pvt *p = data;
 
+	if (p == (struct sip_pvt *) NULL) {
+		ast_log(LOG_ERROR, "We're sent state change for channel we don't know... Major issue!!!!! Notify management!!!\n");
+		return 0;
+	}
 	switch(state) {
 	case AST_EXTENSION_DEACTIVATED:	/* Retry after a while */
 	case AST_EXTENSION_REMOVED:	/* Extension is gone */
@@ -11024,6 +11028,9 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
 	} else if (debug && ignore)
 		ast_verbose("Ignoring this SUBSCRIBE request\n");
 
+	/* Don't treat this SUBSCRIBE request as new if it isn't */
+	if (!p->lastinvite) {
+
 		/* Find parameters to Event: header value and remove them for now */
 		if ((eventparam = strchr(event, ';')))
 			*eventparam++ = '\0';
@@ -11112,6 +11119,7 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
 			if (p->subscribed != MWI_NOTIFICATION)
 				p->stateid = ast_extension_state_add(p->context, p->exten, cb_extensionstate, p);
 		}
+	}
 
 	if (!ignore && p)
 		p->lastinvite = seqno;