Fix a problem with packet-to-packet bridging and DTMF mode translation. P2P

bridging can only be used when the DTMF modes don't match if the core is
monitoring DTMF in both directions.  Then, the core will handle the translation.
Otherwise, this bridging method can not be used.
(issue #8936)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@52645 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/rtp.c

@@ -3187,11 +3187,19 @@ enum ast_bridge_result ast_rtp_bridge(struct ast_channel *c0, struct ast_channel
 	 * |-----------|------------|-----------------------|
 	 * | Inband    | False      | True                  |
 	 * | RFC2833   | True       | True                  |
-	 * | SIP Info  | False      | False                 |
+	 * | SIP INFO  | False      | False                 |
 	 * --------------------------------------------------
+	 * However, if DTMF from both channels is being monitored by the core, then
+	 * we can still do packet-to-packet bridging, because passing through the 
+	 * core will handle DTMF mode translation.
 	 */
 	if ( (ast_test_flag(p0, FLAG_HAS_DTMF) != ast_test_flag(p1, FLAG_HAS_DTMF)) ||
 		 (!c0->tech->send_digit_begin != !c1->tech->send_digit_begin)) {
+		if (!ast_test_flag(p0, FLAG_P2P_NEED_DTMF) || !ast_test_flag(p1, FLAG_P2P_NEED_DTMF)) {
+			ast_channel_unlock(c0);
+			ast_channel_unlock(c1);
+			return AST_BRIDGE_FAILED_NOWARN;
+		}
 		audio_p0_res = AST_RTP_TRY_PARTIAL;
 		audio_p1_res = AST_RTP_TRY_PARTIAL;
 	}