root/net/x25/x25_timer.c

DEFINITIONS

1. x25_init_timers
2. x25_start_heartbeat
3. x25_stop_heartbeat
4. x25_start_t2timer
5. x25_start_t21timer
6. x25_start_t22timer
7. x25_start_t23timer
8. x25_stop_timer
9. x25_display_timer
10. x25_heartbeat_expiry
11. x25_do_timer_expiry
12. x25_timer_expiry

/*
 *      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/jiffies.h>
#include <linux/timer.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/x25.h>

static void x25_heartbeat_expiry(unsigned long);
static void x25_timer_expiry(unsigned long);

void x25_init_timers(struct sock *sk)
{
        struct x25_sock *x25 = x25_sk(sk);

        setup_timer(&x25->timer, x25_timer_expiry, (unsigned long)sk);

        /* initialized by sock_init_data */
        sk->sk_timer.data     = (unsigned long)sk;
        sk->sk_timer.function = &x25_heartbeat_expiry;
}

void x25_start_heartbeat(struct sock *sk)
{
        mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
}

void x25_stop_heartbeat(struct sock *sk)
{
        del_timer(&sk->sk_timer);
}

void x25_start_t2timer(struct sock *sk)
{
        struct x25_sock *x25 = x25_sk(sk);

        mod_timer(&x25->timer, jiffies + x25->t2);
}

void x25_start_t21timer(struct sock *sk)
{
        struct x25_sock *x25 = x25_sk(sk);

        mod_timer(&x25->timer, jiffies + x25->t21);
}

void x25_start_t22timer(struct sock *sk)
{
        struct x25_sock *x25 = x25_sk(sk);

        mod_timer(&x25->timer, jiffies + x25->t22);
}

void x25_start_t23timer(struct sock *sk)
{
        struct x25_sock *x25 = x25_sk(sk);

        mod_timer(&x25->timer, jiffies + x25->t23);
}

void x25_stop_timer(struct sock *sk)
{
        del_timer(&x25_sk(sk)->timer);
}

unsigned long x25_display_timer(struct sock *sk)
{
        struct x25_sock *x25 = x25_sk(sk);

        if (!timer_pending(&x25->timer))
                return 0;

        return x25->timer.expires - jiffies;
}

static void x25_heartbeat_expiry(unsigned long param)
{
        struct sock *sk = (struct sock *)param;

        bh_lock_sock(sk);
        if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
                goto restart_heartbeat;

        switch (x25_sk(sk)->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 (sock_flag(sk, SOCK_DESTROY) ||
                            (sk->sk_state == TCP_LISTEN &&
                             sock_flag(sk, SOCK_DEAD))) {
                                bh_unlock_sock(sk);
                                x25_destroy_socket(sk);
                                return;
                        }
                        break;

                case X25_STATE_3:
                        /*
                         * Check for the state of the receive buffer.
                         */
                        x25_check_rbuf(sk);
                        break;
        }
restart_heartbeat:
        x25_start_heartbeat(sk);
        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)
{
        struct x25_sock *x25 = x25_sk(sk);

        switch (x25->state) {

                case X25_STATE_3:       /* T2 */
                        if (x25->condition & X25_COND_ACK_PENDING) {
                                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);
                        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 (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
                if (x25_sk(sk)->state == X25_STATE_3)
                        x25_start_t2timer(sk);
        } else
                x25_do_timer_expiry(sk);
        bh_unlock_sock(sk);
}