[asterisk-dev] Running channels through dialplan on attended transfer

[Nikša Baldun]

Hello,

information available on channels involved in attended transfer is inadequate for my purposes, so I have created a function which sets some variables on these channels, and also runs transferee and transfer target through dialplan. It works, but I am unsure that I did it correctly. Two specific questions of note:

1. Do I have to set autoservice_chan parameter in ast_app_exec_sub? I don't know what autoservice is.

2. When ast_app_exec_sub is run, the following message appears in debug log:

"Thread LWP 822 is blocking 'PJSIP/444-0000004b', already blocked by thread LWP 6204 in procedure ast_waitfor_nandfds"

I am using fast AGI, and I assume this happens when AGI app is called from dialplan. Is there a way to avoid this?

The function follows (I call it from two_bridge_attended_transfer and ast_bridge_transfer_attended functions).

/*!
 * \internal
 * \brief Set variables on channels involved in attended transfer and run them through dialplan.
 *
 * \param to_transferee The channel that is bridged to the transferee
 * \param to_transfer_target The channel that dialed or is bridged to the transfer target(s)
 * \param transferee_channels A two-channel container containing the transferer and transferee
 * \param to_target_bridge The bridge between to_transfer_target and the transfer_target (NULL if transfer_target did not answer yet)
 *
 * \retval 0 on success.
 * \retval -1 on error.
 */
static int ast_bridge_transfer_attended_to_dialplan(struct ast_channel *to_transferee,
		struct ast_channel *to_transfer_target,
		struct ao2_container *transferee_channels, struct ast_bridge *to_target_bridge)
{
	RAII_VAR(struct ao2_container *, target_channels, NULL, ao2_cleanup);
	RAII_VAR(struct ast_channel *, transferee, NULL, ao2_cleanup);
	RAII_VAR(struct ast_channel *, transfer_target, NULL, ao2_cleanup);
	const char *to_transferee_name;
	const char *to_transfer_target_name;
	const char *transferee_name;
	const char *dialed_channels;

	transferee = get_transferee(transferee_channels, to_transferee);
	if (!transferee)
		return -1;
	if (to_target_bridge) {
		target_channels = ast_bridge_peers_nolock(to_target_bridge);
		if (!target_channels)
			return -1;
		transfer_target = get_transferee(target_channels, to_transfer_target);
	} else {
		transfer_target = NULL;
	}

	ast_channel_lock(to_transferee);
	ast_channel_lock(to_transfer_target);
	ast_channel_lock(transferee);

	to_transferee_name = ast_strdupa(ast_channel_name(to_transferee));
	to_transfer_target_name = ast_strdupa(ast_channel_name(to_transfer_target));
	transferee_name = ast_strdupa(ast_channel_name(transferee));
	dialed_channels = pbx_builtin_getvar_helper(to_transfer_target, "DIALEDCHANNELS");

	pbx_builtin_setvar_helper(to_transferee, ATTENDEDTRANSFERER1, to_transferee_name);
	pbx_builtin_setvar_helper(to_transferee, ATTENDEDTRANSFERER2, to_transfer_target_name);
	ast_channel_unlock(to_transferee);
	pbx_builtin_setvar_helper(to_transfer_target, ATTENDEDTRANSFERER1, to_transferee_name);
	pbx_builtin_setvar_helper(to_transfer_target, ATTENDEDTRANSFERER2, to_transfer_target_name);
	ast_channel_unlock(to_transfer_target);
	pbx_builtin_setvar_helper(transferee, ATTENDEDTRANSFERER1, to_transferee_name);
	pbx_builtin_setvar_helper(transferee, ATTENDEDTRANSFERER2, to_transfer_target_name);
	ast_channel_unlock(transferee);

	ast_app_exec_sub(NULL, transferee, "attended_transferee_connect,s,1", 1);

	if (transfer_target) {
		ast_channel_lock(transfer_target);
		pbx_builtin_setvar_helper(transfer_target, ATTENDEDTRANSFEREE, transferee_name);
		pbx_builtin_setvar_helper(transfer_target, ATTENDEDTRANSFERER1, to_transferee_name);
		pbx_builtin_setvar_helper(transfer_target, ATTENDEDTRANSFERER2, to_transfer_target_name);
		ast_channel_unlock(transfer_target);
		ast_app_exec_sub(NULL, transfer_target, "attended_target_connect,s,1", 1);
	} else {
		if (!ast_strlen_zero(dialed_channels)) {
			char *b_channel_names = ast_strdupa(dialed_channels);
			char *b_channel_name;
			while ((b_channel_name = strtok_r(b_channel_names, " ", &b_channel_names))) {
				struct ast_channel *b_channel = ast_channel_get_by_name(b_channel_name);
				if (b_channel) {
					ast_channel_lock(b_channel);
					pbx_builtin_setvar_helper(b_channel, ATTENDEDTRANSFEREE, transferee_name);
					pbx_builtin_setvar_helper(b_channel, ATTENDEDTRANSFERER1, to_transferee_name);
					pbx_builtin_setvar_helper(b_channel, ATTENDEDTRANSFERER2, to_transfer_target_name);
					ast_channel_unlock(b_channel);
					ast_app_exec_sub(NULL, b_channel, "attended_target_connect,s,1", 1);
					ast_channel_unref(b_channel);
				}
			}
		}
	}

	return 0;
}

-- 
Nikša Baldun

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