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/*

 *      X.25 Packet Layer release 002

 *

 *      This is ALPHA test software. This code may break your machine, randomly fail to work with new

 *      releases, misbehave and/or generally screw up. It might even work.

 *

 *      This code REQUIRES 2.1.15 or higher

 *

 *      This module:

 *              This module 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.

 *

 *      History

 *      X.25 001        Jonathan Naylor Started coding.

 *      X.25 002        Jonathan Naylor New timer architecture.

 *                                      Centralised disconnection processing.

 */

#include <linux/errno.h>

#include <linux/types.h>

#include <linux/socket.h>

#include <linux/in.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/timer.h>

#include <linux/string.h>

#include <linux/sockios.h>

#include <linux/net.h>

#include <linux/inet.h>

#include <linux/netdevice.h>

#include <linux/skbuff.h>

#include <net/sock.h>

#include <asm/segment.h>

#include <asm/system.h>

#include <linux/fcntl.h>

#include <linux/mm.h>

#include <linux/interrupt.h>

#include <net/x25.h>

static void x25_heartbeat_expiry(unsigned long);

static void x25_timer_expiry(unsigned long);

void x25_start_heartbeat(struct sock *sk)

{

        del_timer(&sk->timer);

        sk->timer.data     = (unsigned long)sk;

        sk->timer.function = &x25_heartbeat_expiry;

        sk->timer.expires  = jiffies + 5 * HZ;

        add_timer(&sk->timer);

}

void x25_stop_heartbeat(struct sock *sk)

{

        del_timer(&sk->timer);

}

void x25_start_t2timer(struct sock *sk)

{

        del_timer(&sk->protinfo.x25->timer);

        sk->protinfo.x25->timer.data     = (unsigned long)sk;

        sk->protinfo.x25->timer.function = &x25_timer_expiry;

        sk->protinfo.x25->timer.expires  = jiffies + sk->protinfo.x25->t2;

        add_timer(&sk->protinfo.x25->timer);

}

void x25_start_t21timer(struct sock *sk)

{

        del_timer(&sk->protinfo.x25->timer);

        sk->protinfo.x25->timer.data     = (unsigned long)sk;

        sk->protinfo.x25->timer.function = &x25_timer_expiry;

        sk->protinfo.x25->timer.expires  = jiffies + sk->protinfo.x25->t21;

        add_timer(&sk->protinfo.x25->timer);

}

void x25_start_t22timer(struct sock *sk)

{

        del_timer(&sk->protinfo.x25->timer);

        sk->protinfo.x25->timer.data     = (unsigned long)sk;

        sk->protinfo.x25->timer.function = &x25_timer_expiry;

        sk->protinfo.x25->timer.expires  = jiffies + sk->protinfo.x25->t22;

        add_timer(&sk->protinfo.x25->timer);

}

void x25_start_t23timer(struct sock *sk)

{

        del_timer(&sk->protinfo.x25->timer);

        sk->protinfo.x25->timer.data     = (unsigned long)sk;

        sk->protinfo.x25->timer.function = &x25_timer_expiry;

        sk->protinfo.x25->timer.expires  = jiffies + sk->protinfo.x25->t23;

        add_timer(&sk->protinfo.x25->timer);

}

void x25_stop_timer(struct sock *sk)

{

        del_timer(&sk->protinfo.x25->timer);

}

unsigned long x25_display_timer(struct sock *sk)

{

        if (!timer_pending(&sk->protinfo.x25->timer))

                return 0;

        return sk->protinfo.x25->timer.expires - jiffies;

}

static void x25_heartbeat_expiry(unsigned long param)

{

        struct sock *sk = (struct sock *)param;

        bh_lock_sock(sk);

        if (sk->lock.users) { /* can currently only occur in state 3 */

                goto restart_heartbeat;

        }

        switch (sk->protinfo.x25->state) {

                case X25_STATE_0:

                        /* Magic here: If we listen() and a new link dies before it

                           is accepted() it isn't 'dead' so doesn't get removed. */

                        if (sk->destroy || (sk->state == TCP_LISTEN && sk->dead)) {

                                x25_destroy_socket(sk);

                                goto unlock;

                        }

                        break;

                case X25_STATE_3:

                        /*

                         * Check for the state of the receive buffer.

                         */

                        x25_check_rbuf(sk);

                        break;

        }

 restart_heartbeat:

        x25_start_heartbeat(sk);

 unlock:

        bh_unlock_sock(sk);

}

/*

 *      Timer has expired, it may have been T2, T21, T22, or T23. We can tell

 *      by the state machine state.

 */

static inline void x25_do_timer_expiry(struct sock * sk)

{

        switch (sk->protinfo.x25->state) {

                case X25_STATE_3:       /* T2 */

                        if (sk->protinfo.x25->condition & X25_COND_ACK_PENDING) {

                                sk->protinfo.x25->condition &= ~X25_COND_ACK_PENDING;

                                x25_enquiry_response(sk);

                        }

                        break;

                case X25_STATE_1:       /* T21 */

                case X25_STATE_4:       /* T22 */

                        x25_write_internal(sk, X25_CLEAR_REQUEST);

                        sk->protinfo.x25->state = X25_STATE_2;

                        x25_start_t23timer(sk);

                        break;

                case X25_STATE_2:       /* T23 */

                        x25_disconnect(sk, ETIMEDOUT, 0, 0);

                        break;

        }

}

static void x25_timer_expiry(unsigned long param)

{

        struct sock *sk = (struct sock *)param;

        bh_lock_sock(sk);

        if (sk->lock.users) { /* can currently only occur in state 3 */

                if (sk->protinfo.x25->state == X25_STATE_3) {

                        x25_start_t2timer(sk);

                }

        } else {

                x25_do_timer_expiry(sk);

        }

        bh_unlock_sock(sk);

}