nr_timer.c

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/*
 * 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.
 *
 * Copyright (C) Jonathan Naylor G4KLX ([email protected])
 * Copyright (C) 2002 Ralf Baechle DO1GRB ([email protected])
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <asm/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/netrom.h>

static void nr_heartbeat_expiry(unsigned long);
static void nr_t1timer_expiry(unsigned long);
static void nr_t2timer_expiry(unsigned long);
static void nr_t4timer_expiry(unsigned long);
static void nr_idletimer_expiry(unsigned long);

void nr_init_timers(struct sock *sk)
{
    struct nr_sock *nr = nr_sk(sk);

    setup_timer(&nr->t1timer, nr_t1timer_expiry, (unsigned long)sk);
    setup_timer(&nr->t2timer, nr_t2timer_expiry, (unsigned long)sk);
    setup_timer(&nr->t4timer, nr_t4timer_expiry, (unsigned long)sk);
    setup_timer(&nr->idletimer, nr_idletimer_expiry, (unsigned long)sk);

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

void nr_start_t1timer(struct sock *sk)
{
    struct nr_sock *nr = nr_sk(sk);

    mod_timer(&nr->t1timer, jiffies + nr->t1);
}

void nr_start_t2timer(struct sock *sk)
{
    struct nr_sock *nr = nr_sk(sk);

    mod_timer(&nr->t2timer, jiffies + nr->t2);
}

void nr_start_t4timer(struct sock *sk)
{
    struct nr_sock *nr = nr_sk(sk);

    mod_timer(&nr->t4timer, jiffies + nr->t4);
}

void nr_start_idletimer(struct sock *sk)
{
    struct nr_sock *nr = nr_sk(sk);

    if (nr->idle > 0)
        mod_timer(&nr->idletimer, jiffies + nr->idle);
}

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

void nr_stop_t1timer(struct sock *sk)
{
    del_timer(&nr_sk(sk)->t1timer);
}

void nr_stop_t2timer(struct sock *sk)
{
    del_timer(&nr_sk(sk)->t2timer);
}

void nr_stop_t4timer(struct sock *sk)
{
    del_timer(&nr_sk(sk)->t4timer);
}

void nr_stop_idletimer(struct sock *sk)
{
    del_timer(&nr_sk(sk)->idletimer);
}

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

int nr_t1timer_running(struct sock *sk)
{
    return timer_pending(&nr_sk(sk)->t1timer);
}

static void nr_heartbeat_expiry(unsigned long param)
{
    struct sock *sk = (struct sock *)param;
    struct nr_sock *nr = nr_sk(sk);

    bh_lock_sock(sk);
    switch (nr->state) {
    case NR_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))) {
            sock_hold(sk);
            bh_unlock_sock(sk);
            nr_destroy_socket(sk);
            sock_put(sk);
            return;
        }
        break;

    case NR_STATE_3:
        /*
         * Check for the state of the receive buffer.
         */
        if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
            (nr->condition & NR_COND_OWN_RX_BUSY)) {
            nr->condition &= ~NR_COND_OWN_RX_BUSY;
            nr->condition &= ~NR_COND_ACK_PENDING;
            nr->vl         = nr->vr;
            nr_write_internal(sk, NR_INFOACK);
            break;
        }
        break;
    }

    nr_start_heartbeat(sk);
    bh_unlock_sock(sk);
}

static void nr_t2timer_expiry(unsigned long param)
{
    struct sock *sk = (struct sock *)param;
    struct nr_sock *nr = nr_sk(sk);

    bh_lock_sock(sk);
    if (nr->condition & NR_COND_ACK_PENDING) {
        nr->condition &= ~NR_COND_ACK_PENDING;
        nr_enquiry_response(sk);
    }
    bh_unlock_sock(sk);
}

static void nr_t4timer_expiry(unsigned long param)
{
    struct sock *sk = (struct sock *)param;

    bh_lock_sock(sk);
    nr_sk(sk)->condition &= ~NR_COND_PEER_RX_BUSY;
    bh_unlock_sock(sk);
}

static void nr_idletimer_expiry(unsigned long param)
{
    struct sock *sk = (struct sock *)param;
    struct nr_sock *nr = nr_sk(sk);

    bh_lock_sock(sk);

    nr_clear_queues(sk);

    nr->n2count = 0;
    nr_write_internal(sk, NR_DISCREQ);
    nr->state = NR_STATE_2;

    nr_start_t1timer(sk);
    nr_stop_t2timer(sk);
    nr_stop_t4timer(sk);

    sk->sk_state     = TCP_CLOSE;
    sk->sk_err       = 0;
    sk->sk_shutdown |= SEND_SHUTDOWN;

    if (!sock_flag(sk, SOCK_DEAD)) {
        sk->sk_state_change(sk);
        sock_set_flag(sk, SOCK_DEAD);
    }
    bh_unlock_sock(sk);
}

static void nr_t1timer_expiry(unsigned long param)
{
    struct sock *sk = (struct sock *)param;
    struct nr_sock *nr = nr_sk(sk);

    bh_lock_sock(sk);
    switch (nr->state) {
    case NR_STATE_1:
        if (nr->n2count == nr->n2) {
            nr_disconnect(sk, ETIMEDOUT);
            bh_unlock_sock(sk);
            return;
        } else {
            nr->n2count++;
            nr_write_internal(sk, NR_CONNREQ);
        }
        break;

    case NR_STATE_2:
        if (nr->n2count == nr->n2) {
            nr_disconnect(sk, ETIMEDOUT);
            bh_unlock_sock(sk);
            return;
        } else {
            nr->n2count++;
            nr_write_internal(sk, NR_DISCREQ);
        }
        break;

    case NR_STATE_3:
        if (nr->n2count == nr->n2) {
            nr_disconnect(sk, ETIMEDOUT);
            bh_unlock_sock(sk);
            return;
        } else {
            nr->n2count++;
            nr_requeue_frames(sk);
        }
        break;
    }

    nr_start_t1timer(sk);
    bh_unlock_sock(sk);
}