bridge_native_rtp/bridge_channel: Fix direct media issues due to frame hook

This patch fixes issues with direct media bridges that occur after a blind
transfer. These issues were caught by the (currently failing)
pjsip/transfers/blind_transfer/caller_direct_media test.

The test currently fails primarily for two reasons:
(1) When Bob and Charlie (the transfer target and the transfer destination)
    enter a bridge together, the framehook remains on the transfer target
    channel until both channels are in the bridge. As it consumes voice frames,
    the initial bridge type is a simple bridge. The framehook is removed when
    both channels are in the bridge; however, this does not currently cause the
    bridging framework to re-evaluate the bridge. This patch adds a
    AST_SOFTHANGUP_UNBRIDGE poke to the transfer target channel when a
    framehook is removed so the bridge can re-evaluate itself.

(2) When a channel leaves a native RTP bridge, it may be leaving due to being
    hung up. Sending a re-INVITE to a channel that is about to be hung up is
    not nice - in fact, there's a good chance we'll send the BYE request before
    the channel has had a chance to send back a 200 OK. To be somewhat nicer,
    this patch adds a function to channel.h that allows the bridging framework
    to query for exactly why a channel is leaving a bridge via the channel's
    soft hangup flags. This allows it to only send the re-INVITE if there's a
    chance the channel will survive the native bridging experience.

Review: https://reviewboard.asterisk.org/r/3535/



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/12@414122 65c4cc65-6c06-0410-ace0-fbb531ad65f3

bridges/bridge_native_rtp.c

@@ -230,8 +230,10 @@ static void native_rtp_bridge_stop(struct ast_bridge *bridge, struct ast_channel
 		break;
 	case AST_RTP_GLUE_RESULT_REMOTE:
 		if (!target) {
-			glue0->update_peer(c0->chan, NULL, NULL, NULL, NULL, 0);
+			if (ast_channel_is_leaving_bridge(c0->chan)) {
-			if (glue1) {
+				glue0->update_peer(c0->chan, NULL, NULL, NULL, NULL, 0);
+			}
+			if (glue1 && ast_channel_is_leaving_bridge(c1->chan)) {
 				glue1->update_peer(c1->chan, NULL, NULL, NULL, NULL, 0);
 			}
 		} else {
@@ -485,8 +487,9 @@ static void native_rtp_bridge_leave(struct ast_bridge *bridge, struct ast_bridge
 	}
 
 	/* Direct RTP may have occurred, tear it down */
-	glue->update_peer(bridge_channel->chan, NULL, NULL, NULL, NULL, 0);
+	if (ast_channel_is_leaving_bridge(bridge_channel->chan)) {
-
+		glue->update_peer(bridge_channel->chan, NULL, NULL, NULL, NULL, 0);
+	}
 	native_rtp_bridge_stop(bridge, NULL);
 }
 

include/asterisk/channel.h

@@ -4283,6 +4283,22 @@ struct ast_bridge *ast_channel_get_bridge(const struct ast_channel *chan);
  */
 int ast_channel_is_bridged(const struct ast_channel *chan);
 
+/*!
+ * \brief Determine if a channel is leaving a bridge, but \em not hung up
+ * \since 12.3.0
+ *
+ * \param chan The channel to test
+ *
+ * \note If a channel is hung up, it is implicitly leaving any bridge it
+ * may be in. This function is used to test if a channel is leaving a bridge
+ * but may survive the experience, if it has a place to go to (dialplan or
+ * otherwise)
+ *
+ * \retval 0 The channel is not leaving the bridge or is hung up
+ * \retval non-zero The channel is leaving the bridge
+ */
+int ast_channel_is_leaving_bridge(struct ast_channel *chan);
+
 /*!
  * \brief Get the channel's bridge peer only if the bridge is two-party.
  * \since 12.0.0

main/bridge_channel.c

@@ -1756,9 +1756,9 @@ void bridge_channel_internal_pull(struct ast_bridge_channel *bridge_channel)
 	/* If we are not going to be hung up after leaving a bridge, and we were an
 	 * outgoing channel, clear the outgoing flag.
 	 */
-	if (ast_test_flag(ast_channel_flags(bridge_channel->chan), AST_FLAG_OUTGOING)
+	if (ast_test_flag(ast_channel_flags(bridge_channel->chan), AST_FLAG_OUTGOING) &&
-			&& (ast_channel_softhangup_internal_flag(bridge_channel->chan) & (AST_SOFTHANGUP_ASYNCGOTO | AST_SOFTHANGUP_UNBRIDGE)
+	    (ast_channel_is_leaving_bridge(bridge_channel->chan) ||
-			    || bridge_channel->state == BRIDGE_CHANNEL_STATE_WAIT)) {
+	     bridge_channel->state == BRIDGE_CHANNEL_STATE_WAIT)) {
 		ast_debug(2, "Channel %s will survive this bridge; clearing outgoing (dialed) flag\n", ast_channel_name(bridge_channel->chan));
 		ast_clear_flag(ast_channel_flags(bridge_channel->chan), AST_FLAG_OUTGOING);
 	}

main/channel.c

@@ -10151,6 +10151,18 @@ int ast_channel_is_bridged(const struct ast_channel *chan)
 	return ast_channel_internal_bridge(chan) != NULL;
 }
 
+int ast_channel_is_leaving_bridge(struct ast_channel *chan)
+{
+	int flags = ast_channel_softhangup_internal_flag(chan);
+
+	/* We test the flags independently here in case they are masked with
+	 * actual "hangup" soft-hangup flags
+	 */
+	return (flags == AST_SOFTHANGUP_ASYNCGOTO ||
+	        flags == AST_SOFTHANGUP_UNBRIDGE ||
+	        flags == (AST_SOFTHANGUP_ASYNCGOTO | AST_SOFTHANGUP_UNBRIDGE));
+}
+
 struct ast_channel *ast_channel_bridge_peer(struct ast_channel *chan)
 {
 	struct ast_channel *peer;

main/framehook.c

@@ -189,6 +189,10 @@ int ast_framehook_detach(struct ast_channel *chan, int id)
 	}
 	AST_LIST_TRAVERSE_SAFE_END;
 
+	if (ast_channel_is_bridged(chan)) {
+		ast_softhangup_nolock(chan, AST_SOFTHANGUP_UNBRIDGE);
+	}
+
 	return res;
 }
 

res/res_pjsip_session.c

@@ -780,6 +780,9 @@ int ast_sip_session_refresh(struct ast_sip_session *session,
 			return -1;
 		}
 	}
+	ast_debug(3, "Sending session refresh SDP via %s to %s\n",
+		method == AST_SIP_SESSION_REFRESH_METHOD_INVITE ? "re-INVITE" : "UPDATE",
+		ast_sorcery_object_get_id(session->endpoint));
 	ast_sip_session_send_request_with_cb(session, tdata, on_response);
 	return 0;
 }