pjsip/include/pjsip-ua/sip_xfer.h

/* $Id$ */
/* 
 * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#ifndef __PJSIP_XFER_H__
#define __PJSIP_XFER_H__



/**
 * @file sip_xfer.h
 * @brief SIP Transfer (REFER, RFC 3515)
 */
#include <pjsip-simple/evsub.h>
#include <pjsip/sip_msg.h>

/**
 * @defgroup PJSUA_XFER SIP REFER (RFC 3515) for Call Transfer etc.
 * @ingroup PJSIP_HIGH_UA
 * @brief SIP REFER dialog usage (call transfer, etc.)
 * @{
 *
 * This describes a generic handling of SIP REFER request. The SIP REFER
 * request is described in RFC 3515, and commonly used to perform call
 * transfer functionality. Other types of SIP REFER usages are described
 * in draft-worley-sip-many-refers-00 draft, for example:
 *  - Remote Dial: where UAC sends REFER to instruct REFER recipient to
 *    initiate an INVITE session to some target.
 * 
 * A REFER request can be sent inside or outside existing dialog context,
 * although for call transfer case, it is more common to send REFER inside
 * existing INVITE session context. PJSIP supports both sending REFER request
 * inside or outside dialog context.
 *
 * The REFER framework uses @ref PJSIP_EVENT_NOT to manage the event
 * subscription created by the REFER request. Because of this, application 
 * must link with <b>pjsip-ua</b> AND <b>pjsip-simple</b> static libraries 
 * to use REFER functionality.
 *
 * Reference:
 *  - <A HREF="http://www.ietf.org/rfc/rfc3515.txt">RFC 3515: The Session 
 *    Initiation Protocol (SIP) Refer Method</A>
 *  - @ref PJSIP_EVENT_NOT
 */


PJ_BEGIN_DECL


/** Declaration for REFER method constant. */
PJ_DECL_DATA(const pjsip_method) pjsip_refer_method;

/** Get REFER method constant */
PJ_DECL(const pjsip_method*) pjsip_get_refer_method();


/**
 * Initialize the REFER subsystem.
 * This currently does very little (only register REFER as supported method).
 */
PJ_DECL(pj_status_t) pjsip_xfer_init_module(pjsip_endpoint *endpt);



/**
 * Create transferer (sender of REFER request).
 *
 * @param dlg		The underlying dialog to use.
 * @param user_cb	Pointer to callbacks to receive presence subscription
 *			events.
 * @param p_evsub	Pointer to receive the presence subscription
 *			session.
 *
 * @return		PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjsip_xfer_create_uac( pjsip_dialog *dlg,
					    const pjsip_evsub_user *user_cb,
					    pjsip_evsub **p_evsub );


/**
 * Create transferee (receiver of REFER request).
 *
 * @param dlg		The underlying dialog to use.
 * @param user_cb	Pointer to callbacks to receive presence subscription
 *			events.
 * @param rdata		The incoming SUBSCRIBE request that creates the event 
 *			subscription.
 * @param p_evsub	Pointer to receive the presence subscription
 *			session.
 *
 * @return		PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjsip_xfer_create_uas( pjsip_dialog *dlg,
					    const pjsip_evsub_user *user_cb,
					    pjsip_rx_data *rdata,
					    pjsip_evsub **p_evsub );

/**
 * Call this function to create request to initiate REFER subscription,
 * to refresh subscription, or to unsubscribe. For request other than
 * the initial REFER request, "refer_to_uri" argument may be NULL.
 *
 * @param sub		Client subscription instance.
 * @param refer_to_uri	URI to be put to the Refer-To header. This argument
 *			may be NULL for subsequent REFER requests.
 * @param p_tdata	Pointer to receive the request.
 *
 * @return		PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjsip_xfer_initiate( pjsip_evsub *sub,
					  const pj_str_t *refer_to_uri,
					  pjsip_tx_data **p_tdata);


/**
 * Accept the incoming REFER request by sending 2xx response.
 *
 * @param sub		Server subscription instance.
 * @param rdata		The incoming subscription request message.
 * @param st_code	Status code, which MUST be 2xx.
 * @param hdr_list	Optional list of headers to be added in the response.
 *
 * @return		PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjsip_xfer_accept( pjsip_evsub *sub,
					pjsip_rx_data *rdata,
				        int st_code,
					const pjsip_hdr *hdr_list );


/**
 * For notifier, create NOTIFY request to subscriber, and set the state 
 * of the subscription. 
 *
 * @param sub		The server subscription (notifier) instance.
 * @param state		New state to set.
 * @param xfer_st_code	The call status code to be reported with the NOTIFY
 *			request.
 * @param xfer_st_text	Optional call status text to be reported with the 
 *			NOTIFY request. If the value is NULL, default 
 *			status text will be used.
 * @param p_tdata	Pointer to receive the request.
 *
 * @return		PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjsip_xfer_notify( pjsip_evsub *sub,
					pjsip_evsub_state state,
					int xfer_st_code,
					const pj_str_t *xfer_st_text,
					pjsip_tx_data **p_tdata);


/**
 * Create NOTIFY request to reflect current subscription status. Application
 * can only call this function after it has sent NOTIFY before.
 * This will also re-send the last "message/sipfrag" body that was sent
 * in the previous NOTIFY.
 *
 * @param sub		Server subscription object.
 * @param p_tdata	Pointer to receive request.
 *
 * @return		PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjsip_xfer_current_notify( pjsip_evsub *sub,
					        pjsip_tx_data **p_tdata );



/**
 * Send request message that was previously created with initiate(), notify(),
 * or current_notify(). Application may also send request created with other
 * functions, e.g. authentication. But the request MUST be either request
 * that creates/refresh subscription or NOTIFY request.
 *
 *
 * @param sub		The event subscription object.
 * @param tdata		Request message to be send.
 *
 * @return		PJ_SUCCESS on success.
 */
PJ_DECL(pj_status_t) pjsip_xfer_send_request( pjsip_evsub *sub,
					      pjsip_tx_data *tdata);


PJ_END_DECL

/**
 * @}
 */

#endif	/* __PJSIP_XFER_H__ */