res_pjsip_header_funcs: Don't add headers to re-INVITEs.

When sending a re-INVITE to an endpoint it was possible for received
headers to be added as well (since they are stored for retrieval using
the PJSIP_HEADER dialplan function). This caused a broken (and
potentially large) SIP INVITE to be produced and sent.

This changes the module so it will no longer add headers to
re-INVITEs.

(closes issue ASTERISK-22882)
Reported by: David M. Lee
........

Merged revisions 403221 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@403222 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_pjsip_header_funcs.c

@@ -583,7 +583,8 @@ static void outgoing_request(struct ast_sip_session *session, pjsip_tx_data * td
 	RAII_VAR(struct ast_datastore *, datastore,
 			 ast_sip_session_get_datastore(session, header_datastore.type), ao2_cleanup);
 
-	if (!datastore || !datastore->data) {
+	if (!datastore || !datastore->data ||
+		(session->inv_session->state >= PJSIP_INV_STATE_CONFIRMED)) {
 		return;
 	}