/* $Id: stun_session.h 1275 2007-05-15 10:42:56Z bennylp $ */
/* 
 * Copyright (C) 2003-2005 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 __PJNATH_STUN_SESSION_H__
#define __PJNATH_STUN_SESSION_H__

/**
 * @file stun_session.h
 * @brief STUN session management for client/server.
 */

#include <pjnath/stun_msg.h>
#include <pjnath/stun_auth.h>
#include <pjnath/stun_config.h>
#include <pjnath/stun_transaction.h>
#include <pj/list.h>
#include <pj/timer.h>

PJ_BEGIN_DECL


/* **************************************************************************/
/**
 * @defgroup PJNATH_STUN_SESSION STUN Client/Server Session
 * @brief STUN client and server session
 * @ingroup PJNATH_STUN
 * @{
 */


/** Forward declaration for pj_stun_tx_data */
typedef struct pj_stun_tx_data pj_stun_tx_data;

/** Forward declaration for pj_stun_session */
typedef struct pj_stun_session pj_stun_session;


/**
 * This is the callback to be registered to pj_stun_session, to send
 * outgoing message and to receive various notifications from the STUN
 * session.
 */
typedef struct pj_stun_session_cb
{
    /**
     * Callback to be called by the STUN session to send outgoing message.
     *
     * @param sess	    The STUN session.
     * @param pkt	    Packet to be sent.
     * @param pkt_size	    Size of the packet to be sent.
     * @param dst_addr	    The destination address.
     * @param addr_len	    Length of destination address.
     *
     * @return		    The callback should return the status of the
     *			    packet sending.
     */
    pj_status_t (*on_send_msg)(pj_stun_session *sess,
			       const void *pkt,
			       pj_size_t pkt_size,
			       const pj_sockaddr_t *dst_addr,
			       unsigned addr_len);

    /** 
     * Callback to be called on incoming STUN request message. In the 
     * callback processing, application MUST create a response by calling
     * pj_stun_session_create_response() function and send the response
     * with pj_stun_session_send_msg() function, before returning from
     * the callback.
     *
     * @param sess	    The STUN session.
     * @param pkt	    Pointer to the original STUN packet.
     * @param pkt_len	    Length of the STUN packet.
     * @param msg	    The parsed STUN request.
     * @param src_addr	    Source address of the packet.
     * @param src_addr_len  Length of the source address.
     *
     * @return		    The return value of this callback will be
     *			    returned back to pj_stun_session_on_rx_pkt()
     *			    function.
     */
    pj_status_t (*on_rx_request)(pj_stun_session *sess,
				 const pj_uint8_t *pkt,
				 unsigned pkt_len,
				 const pj_stun_msg *msg,
				 const pj_sockaddr_t *src_addr,
				 unsigned src_addr_len);

    /**
     * Callback to be called when response is received or the transaction 
     * has timed out.
     *
     * @param sess	    The STUN session.
     * @param status	    Status of the request. If the value if not
     *			    PJ_SUCCESS, the transaction has timed-out
     *			    or other error has occurred, and the response
     *			    argument may be NULL.
     *			    Note that when the status is not success, the
     *			    response may contain non-NULL value if the 
     *			    response contains STUN ERROR-CODE attribute.
     * @param request	    The original STUN request.
     * @param response	    The response message, on successful transaction,
     *			    or otherwise MAY BE NULL if status is not success.
     *			    Note that when the status is not success, this
     *			    argument may contain non-NULL value if the 
     *			    response contains STUN ERROR-CODE attribute.
     * @param src_addr	    The source address where the response was 
     *			    received, or NULL if the response is NULL.
     * @param src_addr_len  The length of the source  address.
     */
    void (*on_request_complete)(pj_stun_session *sess,
			        pj_status_t status,
			        pj_stun_tx_data *tdata,
			        const pj_stun_msg *response,
				const pj_sockaddr_t *src_addr,
				unsigned src_addr_len);


    /**
     * Type of callback to be called on incoming STUN indication.
     */
    pj_status_t (*on_rx_indication)(pj_stun_session *sess,
				    const pj_uint8_t *pkt,
				    unsigned pkt_len,
				    const pj_stun_msg *msg,
				    const pj_sockaddr_t *src_addr,
				    unsigned src_addr_len);

} pj_stun_session_cb;


/**
 * This structure describe the outgoing STUN transmit data to carry the
 * message to be sent.
 */
struct pj_stun_tx_data
{
    PJ_DECL_LIST_MEMBER(struct pj_stun_tx_data);

    pj_pool_t		*pool;		/**< Pool.			    */
    pj_stun_session	*sess;		/**< The STUN session.		    */
    pj_stun_msg		*msg;		/**< The STUN message.		    */

    void		*user_data;	/**< Arbitrary application data.    */

    pj_stun_client_tsx	*client_tsx;	/**< Client STUN transaction.	    */
    pj_uint32_t		 msg_magic;	/**< Message magic.		    */
    pj_uint8_t		 msg_key[12];	/**< Message/transaction key.	    */

    pj_str_t		 auth_key;	/**< Auth key.			    */

    void		*pkt;		/**< The STUN packet.		    */
    unsigned		 max_len;	/**< Length of packet buffer.	    */
    unsigned		 pkt_size;	/**< The actual length of STUN pkt. */

    unsigned		 addr_len;	/**< Length of destination address. */
    const pj_sockaddr_t	*dst_addr;	/**< Destination address.	    */

    pj_timer_entry	 res_timer;	/**< Response cache timer.	    */
};


/**
 * Create a STUN session.
 *
 * @param cfg		The STUN endpoint, to be used to register timers etc.
 * @param name		Optional name to be associated with this instance. The
 *			name will be used for example for logging purpose.
 * @param cb		Session callback.
 * @param fingerprint	Enable message fingerprint for outgoing messages.
 * @param p_sess	Pointer to receive STUN session instance.
 *
 * @return	    PJ_SUCCESS on success, or the appropriate error code.
 */
PJ_DECL(pj_status_t) pj_stun_session_create(pj_stun_config *cfg,
					    const char *name,
					    const pj_stun_session_cb *cb,
					    pj_bool_t fingerprint,
					    pj_stun_session **p_sess);

/**
 * Destroy the STUN session.
 *
 * @param sess	    The STUN session instance.
 *
 * @return	    PJ_SUCCESS on success, or the appropriate error code.
 */
PJ_DECL(pj_status_t) pj_stun_session_destroy(pj_stun_session *sess);

/**
 * Associated an arbitrary data with this STUN session. The user data may
 * be retrieved later with pj_stun_session_get_user_data() function.
 *
 * @param sess	    The STUN session instance.
 * @param user_data The user data.
 *
 * @return	    PJ_SUCCESS on success, or the appropriate error code.
 */
PJ_DECL(pj_status_t) pj_stun_session_set_user_data(pj_stun_session *sess,
						   void *user_data);

/**
 * Retrieve the user data previously associated to this STUN session with