Add SIPREFERRINGCONTEXT and SIPREFERREDBYHDR variables when a transfer takes place. (issue #8378 reported by jcovert)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@72354 65c4cc65-6c06-0410-ace0-fbb531ad65f3

CHANGES

@@ -60,6 +60,7 @@ SIP changes
      in this file of the "pollmailboxes" and "pollfreq" options to voicemail.conf 
      for more information.
   * Added rtpdest option to CHANNEL() dialplan function.
+  * Added SIPREFERRINGCONTEXT and SIPREFERREDBYHDR variables which are set when a transfer takes place.
 
 IAX2 changes
 ------------

channels/chan_sip.c

@@ -9340,6 +9340,16 @@ static int get_refer_info(struct sip_pvt *transferer, struct sip_request *outgoi
 
 	/* Get referred by header if it exists */
 	p_referred_by = get_header(req, "Referred-By");
+
+	/* Give useful transfer information to the dialplan */
+	if (transferer->owner) {
+		struct ast_channel *peer = ast_bridged_channel(transferer->owner);
+		if (peer) {
+			pbx_builtin_setvar_helper(peer, "SIPREFERRINGCONTEXT", transferer->context);
+			pbx_builtin_setvar_helper(peer, "SIPREFERREDBYHDR", p_referred_by);
+		}
+	}
+
 	if (!ast_strlen_zero(p_referred_by)) {
 		char *lessthan;
 		h_referred_by = ast_strdupa(p_referred_by);