framehooks: Add callback for determining if a hook is consuming frames of a specific type.

In the past framehooks have had no capability to determine what frame types a hook
is actually interested in consuming. This has meant that code has had to assume they
want all frames, thus preventing native bridging.

This change adds a callback which allows a framehook to be queried for whether it
is consuming a frame of a specific type. The native RTP bridging module has also
been updated to take advantange of this, allowing native bridging to occur when
previously it would not.

ASTERISK-23497 #comment Reported by: Etienne Lessard
ASTERISK-23497 #close

Review: https://reviewboard.asterisk.org/r/3522/
........

Merged revisions 413681 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@413682 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/bridge_basic.c

@@ -2614,6 +2614,12 @@ static struct ast_frame *transfer_target_framehook_cb(struct ast_channel *chan,
 	return frame;
 }
 
+/*! \brief Callback function which informs upstream if we are consuming a frame of a specific type */
+static int transfer_target_framehook_consume(void *data, enum ast_frame_type type)
+{
+	return (type == AST_FRAME_CONTROL ? 1 : 0);
+}
+
 static void transfer_target_framehook_destroy_cb(void *data)
 {
 	struct attended_transfer_properties *props = data;
@@ -2847,6 +2853,7 @@ static int attach_framehook(struct attended_transfer_properties *props, struct a
 		.version = AST_FRAMEHOOK_INTERFACE_VERSION,
 		.event_cb = transfer_target_framehook_cb,
 		.destroy_cb = transfer_target_framehook_destroy_cb,
+		.consume_cb = transfer_target_framehook_consume,
 	};
 
 	ao2_ref(props, +1);