/* 
 * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
 * 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 __PJNATH_STUN_SOCK_H__
#define __PJNATH_STUN_SOCK_H__

/**
 * @file stun_sock.h
 * @brief STUN aware socket transport
 */
#include <pjnath/stun_config.h>
#include <pjlib-util/resolver.h>
#include <pj/ioqueue.h>
#include <pj/lock.h>
#include <pj/sock.h>
#include <pj/sock_qos.h>


PJ_BEGIN_DECL


/**
 * @addtogroup PJNATH_STUN_SOCK
 * @{
 *
 * The STUN transport provides asynchronous UDP like socket transport
 * with the additional STUN capability. It has the following features:
 *
 *  - API to send and receive UDP packets
 *
 *  - multiplex STUN and non-STUN incoming packets and distinguish between
 *    STUN responses that belong to internal requests with application data
 *    (the application data may be STUN packets as well)
 *
 *  - DNS SRV resolution to the STUN server (if wanted), along with fallback
 *    to DNS A resolution if SRV record is not found.
 *
 *  - STUN keep-alive maintenance, and handle changes to the mapped address
 *    (when the NAT binding changes)
 *
 */

/**
 * Opaque type to represent a STUN transport.
 */
typedef struct pj_stun_sock pj_stun_sock;

/**
 * Types of operation being reported in \a on_status() callback of
 * pj_stun_sock_cb. Application may retrieve the string representation
 * of these constants with pj_stun_sock_op_name().
 */
typedef enum pj_stun_sock_op
{
    /**
     * Asynchronous DNS resolution.
     */
    PJ_STUN_SOCK_DNS_OP         = 1,

    /**
     * Initial STUN Binding request.
     */
    PJ_STUN_SOCK_BINDING_OP,

    /**
     * Subsequent STUN Binding request for keeping the binding
     * alive.
     */
    PJ_STUN_SOCK_KEEP_ALIVE_OP,

    /**
     * IP address change notification from the keep-alive operation.
     */
    PJ_STUN_SOCK_MAPPED_ADDR_CHANGE


} pj_stun_sock_op;


/**
 * This structure contains callbacks that will be called by the STUN
 * transport to notify application about various events.
 */
typedef struct pj_stun_sock_cb
{
    /**
     * Notification when incoming packet has been received.
     *
     * @param stun_sock The STUN transport.
     * @param data      The packet.
     * @param data_len  Length of the packet.
     * @param src_addr  The source address of the packet.
     * @param addr_len  The length of the source address.
     *
     * @return          Application should normally return PJ_TRUE to let
     *                  the STUN transport continue its operation. However
     *                  it must return PJ_FALSE if it has destroyed the
     *                  STUN transport in this callback.
     */
    pj_bool_t (*on_rx_data)(pj_stun_sock *stun_sock,
                            void *pkt,
                            unsigned pkt_len,
                            const pj_sockaddr_t *src_addr,
                            unsigned addr_len);

    /**
     * Notifification when asynchronous send operation has completed.
     *
     * @param stun_sock The STUN transport.
     * @param send_key  The send operation key that was given in
     *                  #pj_stun_sock_sendto().
     * @param sent      If value is positive non-zero it indicates the
     *                  number of data sent. When the value is negative,
     *                  it contains the error code which can be retrieved
     *                  by negating the value (i.e. status=-sent).
     *
     * @return          Application should normally return PJ_TRUE to let
     *                  the STUN transport continue its operation. However
     *                  it must return PJ_FALSE if it has destroyed the
     *                  STUN transport in this callback.
     */
    pj_bool_t (*on_data_sent)(pj_stun_sock *stun_sock,
                              pj_ioqueue_op_key_t *send_key,
                              pj_ssize_t sent);

    /**
     * Notification when the status of the STUN transport has changed. This
     * callback may be called for the following conditions:
     *  - the first time the publicly mapped address has been resolved from
     *    the STUN server, this callback will be called with \a op argument
     *    set to PJ_STUN_SOCK_BINDING_OP \a status  argument set to 
     *    PJ_SUCCESS.
     *  - anytime when the transport has detected that the publicly mapped
     *    address has changed, this callback will be called with \a op
     *    argument set to PJ_STUN_SOCK_KEEP_ALIVE_OP and \a status
     *    argument set to PJ_SUCCESS. On this case and the case above,
     *    application will get the resolved public address in the
     *    #pj_stun_sock_info structure.
     *  - for any terminal error (such as STUN time-out, DNS resolution
     *    failure, or keep-alive failure), this callback will be called 
     *    with the \a status argument set to non-PJ_SUCCESS.
     *
     * @param stun_sock The STUN transport.
     * @param op        The operation that triggers the callback.
     * @param status    The status.
     *
     * @return          Must return PJ_FALSE if it has destroyed the
     *                  STUN transport in this callback. Application should
     *                  normally destroy the socket and return PJ_FALSE
     *                  upon encountering terminal error, otherwise it
     *                  should return PJ_TRUE to let the STUN socket operation
     *                  continues.
     */
    pj_bool_t   (*on_status)(pj_stun_sock *stun_sock, 
                             pj_stun_sock_op op,
                             pj_status_t status);

} pj_stun_sock_cb;


/**
 * This structure contains information about the STUN transport. Application
 * may query this information by calling #pj_stun_sock_get_info().
 */
typedef struct pj_stun_sock_info
{
    /**
     * The bound address of the socket.
     */
    pj_sockaddr     bound_addr;

    /**
     * IP address of the STUN server.
     */
    pj_sockaddr     srv_addr;

    /**
     * The publicly mapped address. It may contain zero address when the
     * mapped address has not been resolved. Application may query whether
     * this field contains valid address with pj_sockaddr_has_addr().
     */
    pj_sockaddr     mapped_addr;

    /**
     * Number of interface address aliases. The interface address aliases
     * are list of all interface addresses in this host.
     */
    unsigned        alias_cnt;

    /**
     * Array of interface address aliases.
     */
    pj_sockaddr     aliases[PJ_ICE_ST_MAX_CAND];

} pj_stun_sock_info;


/**
 * This describe the settings to be given to the STUN transport during its
 * creation. Application should initialize this structure by calling
 * #pj_stun_sock_cfg_default().
 */
typedef struct pj_stun_sock_cfg
{
    /**
     * The group lock to be used by the STUN socket. If NULL, the STUN socket
     * will create one internally.
     *
     * Default: NULL
     */
    pj_grp_lock_t *grp_lock;

    /**
     * Packet buffer size.
     *
     * Default value is PJ_STUN_SOCK_PKT_LEN.
     */
    unsigned max_pkt_size;

    /**
     * Specify the number of simultaneous asynchronous read operations to
     * be invoked to the ioqueue. Having more than one read operations will
     * increase performance on multiprocessor systems since the application
     * will be able to process more than one incoming packets simultaneously.
     * Default value is 1.
     */
    unsigned async_cnt;

    /**
     * Specify the interface where the socket should be bound to. If the
     * address is zero, socket will be bound to INADDR_ANY. If the address
     * is non-zero, socket will be bound to this address only, and the
     * transport will have only one address alias (the \a alias_cnt field
     * in #pj_stun_sock_info structure. If the port is set to zero, the
     * socket will bind at any port (chosen by the OS).
     */
    pj_sockaddr bound_addr;

    /**
     * Specify the port range for STUN socket binding, relative to the start
     * port number specified in \a bound_addr. Note that this setting is only
     * applicable when the start port number is non zero.
     *
     * Default value is zero.
     */
    pj_uint16_t port_range;

    /**
     * Specify the STUN keep-alive duration, in seconds. The STUN transport
     * does keep-alive by sending STUN Binding request to the STUN server. 
     * If this value is zero, the PJ_STUN_KEEP_ALIVE_SEC value will be used.
     * If the value is negative, it will disable STUN keep-alive.
     */
    int ka_interval;

    /**
     * QoS traffic type to be set on this transport. When application wants
     * to apply QoS tagging to the transport, it's preferable to set this
     * field rather than \a qos_param fields since this is more portable.
     *
     * Default value is PJ_QOS_TYPE_BEST_EFFORT.
     */
    pj_qos_type qos_type;

    /**
     * Set the low level QoS parameters to the transport. This is a lower
     * level operation than setting the \a qos_type field and may not be
     * supported on all platforms.
     *
     * By default all settings in this structure are disabled.
     */
    pj_qos_params qos_params;

    /**
     * Specify if STUN socket should ignore any errors when setting the QoS
     * traffic type/parameters.
     *
     * Default: PJ_TRUE
     */
    pj_bool_t qos_ignore_error;

    /**
     * Specify target value for socket receive buffer size. It will be
     * applied using setsockopt(). When it fails to set the specified size,
     * it will try with lower value until the highest possible is
     * successfully set.
     *
     * Default: 0 (OS default)
     */
    unsigned so_rcvbuf_size;

    /**
     * Specify target value for socket send buffer size. It will be
     * applied using setsockopt(). When it fails to set the specified size,
     * it will try with lower value until the highest possible is
     * successfully set.
     *
     * Default: 0 (OS default)
     */
    unsigned so_sndbuf_size;

} pj_stun_sock_cfg;



/**
 * Retrieve the name representing the specified operation.
 */
PJ_DECL(const char*) pj_stun_sock_op_name(pj_stun_sock_op op);


/**
 * Initialize the STUN transport setting with its default values.
 *
 * @param cfg   The STUN transport config.
 */
PJ_DECL(void) pj_stun_sock_cfg_default(pj_stun_sock_cfg *cfg);


/**
 * Create the STUN transport using the specified configuration. Once
 * the STUN transport has been create, application should call
 * #pj_stun_sock_start() to start the transport.
 *
 * @param stun_cfg      The STUN configuration which contains among other
 *                      things the ioqueue and timer heap instance for
 *                      the operation of this transport.
 * @param af            Address family of socket. Currently pj_AF_INET()
 *                      and pj_AF_INET6() are supported. 
 * @param name          Optional name to be given to this transport to
 *                      assist debugging.
 * @param cb            Callback to receive events/data from the transport.
 * @param cfg           Optional transport settings.
 * @param user_data     Arbitrary application data to be associated with
 *                      this transport.
 * @param p_sock        Pointer to receive the created transport instance.
 *
 * @return              PJ_SUCCESS if the operation has been successful,
 *                      or the appropriate error code on failure.
 */
PJ_DECL(pj_status_t) pj_stun_sock_create(pj_stun_config *stun_cfg,
                                         const char *name,
                                         int af,
                                         const pj_stun_sock_cb *cb,
                                         const pj_stun_sock_cfg *cfg,
                                         void *user_data,
                                         pj_stun_sock **p_sock);


/**
 * Start the STUN transport. This will start the DNS SRV resolution for
 * the STUN server (if desired), and once the server is resolved, STUN
 * Binding request will be sent to resolve the publicly mapped address.
 * Once the initial STUN Binding response is received, the keep-alive
 * timer will be started.
 *
 * @param stun_sock     The STUN transport instance.
 * @param domain        The domain, hostname, or IP address of the STUN
 *                      server. When this parameter contains domain name,
 *                      the \a resolver parameter must be set to activate
 *                      DNS SRV resolution.
 * @param default_port  The default STUN port number to use when DNS SRV
 *                      resolution is not used. If DNS SRV resolution is
 *                      used, the server port number will be set from the
 *                      DNS SRV records. The recommended value for this
 *                      parameter is PJ_STUN_PORT.
 * @param resolver      If this parameter is not NULL, then the \a domain
 *                      parameter will be first resolved with DNS SRV and
 *                      then fallback to using DNS A/AAAA resolution when
 *                      DNS SRV resolution fails. If this parameter is
 *                      NULL, the \a domain parameter will be resolved as
 *                      hostname.
 *
 * @return              PJ_SUCCESS if the operation has been successfully
 *                      queued, or the appropriate error code on failure.
 *                      When this function returns PJ_SUCCESS, the final
 *                      result of the allocation process will be notified
 *                      to application in \a on_status() callback.
 */
PJ_DECL(pj_status_t) pj_stun_sock_start(pj_stun_sock *stun_sock,
                                        const pj_str_t *domain,
                                        pj_uint16_t default_port,
                                        pj_dns_resolver *resolver);

/**
 * Destroy the STUN transport.
 *
 * @param sock          The STUN transport socket.
 *
 * @return              PJ_SUCCESS if the operation has been successful,
 *                      or the appropriate error code on failure.
 */
PJ_DECL(pj_status_t) pj_stun_sock_destroy(pj_stun_sock *sock);


/**
 * Associate a user data with this STUN transport. The user data may then
 * be retrieved later with #pj_stun_sock_get_user_data().
 *
 * @param stun_sock     The STUN transport instance.
 * @param user_data     Arbitrary data.
 *
 * @return              PJ_SUCCESS if the operation has been successful,
 *                      or the appropriate error code on failure.
 */
PJ_DECL(pj_status_t) pj_stun_sock_set_user_data(pj_stun_sock *stun_sock,
                                                void *user_data);

/**
 * Retrieve the previously assigned user data associated with this STUN
 * transport.
 *
 * @param stun_sock     The STUN transport instance.
 *
 * @return              The user/application data.
 */
PJ_DECL(void*) pj_stun_sock_get_user_data(pj_stun_sock *stun_sock);


/**
 * Get the group lock for this STUN transport.
 *
 * @param stun_sock     The STUN transport instance.
 *
 * @return              The group lock.
 */
PJ_DECL(pj_grp_lock_t *) pj_stun_sock_get_grp_lock(pj_stun_sock *stun_sock);


/**
 * Get the STUN transport info. The transport info contains, among other
 * things, the allocated relay address.
 *
 * @param stun_sock     The STUN transport instance.
 * @param info          Pointer to be filled with STUN transport info.
 *
 * @return              PJ_SUCCESS if the operation has been successful,
 *                      or the appropriate error code on failure.
 */
PJ_DECL(pj_status_t) pj_stun_sock_get_info(pj_stun_sock *stun_sock,
                                           pj_stun_sock_info *info);


/**
 * Send a data to the specified address. This function may complete
 * asynchronously and in this case \a on_data_sent() will be called.
 *
 * @param stun_sock     The STUN transport instance.
 * @param send_key      Optional send key for sending the packet down to
 *                      the ioqueue. This value will be given back to
 *                      \a on_data_sent() callback
 * @param pkt           The data/packet to be sent to peer.
 * @param pkt_len       Length of the data.
 * @param flag          pj_ioqueue_sendto() flag.
 * @param dst_addr      The remote address.
 * @param addr_len      Length of the address.
 *
 * @return              PJ_SUCCESS if data has been sent immediately, or
 *                      PJ_EPENDING if data cannot be sent immediately. In
 *                      this case the \a on_data_sent() callback will be
 *                      called when data is actually sent. Any other return
 *                      value indicates error condition.
 */ 
PJ_DECL(pj_status_t) pj_stun_sock_sendto(pj_stun_sock *stun_sock,
                                         pj_ioqueue_op_key_t *send_key,
                                         const void *pkt,
                                         unsigned pkt_len,
                                         unsigned flag,
                                         const pj_sockaddr_t *dst_addr,
                                         unsigned addr_len);

/**
 * @}
 */


PJ_END_DECL


#endif  /* __PJNATH_STUN_SOCK_H__ */

