ax25_std_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) Alan Cox GW4PTS ([email protected])
 * Copyright (C) Jonathan Naylor G4KLX ([email protected])
 * Copyright (C) Joerg Reuter DL1BKE ([email protected])
 * Copyright (C) Frederic Rible F1OAT ([email protected])
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.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>

void ax25_std_heartbeat_expiry(ax25_cb *ax25)
{
    struct sock *sk = ax25->sk;

    if (sk)
        bh_lock_sock(sk);

    switch (ax25->state) {
    case AX25_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 || sock_flag(sk, SOCK_DESTROY) ||
            (sk->sk_state == TCP_LISTEN &&
             sock_flag(sk, SOCK_DEAD))) {
            if (sk) {
                sock_hold(sk);
                ax25_destroy_socket(ax25);
                bh_unlock_sock(sk);
                sock_put(sk);
            } else
                ax25_destroy_socket(ax25);
            return;
        }
        break;

    case AX25_STATE_3:
    case AX25_STATE_4:
        /*
         * Check the state of the receive buffer.
         */
        if (sk != NULL) {
            if (atomic_read(&sk->sk_rmem_alloc) <
                (sk->sk_rcvbuf >> 1) &&
                (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
                ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
                ax25->condition &= ~AX25_COND_ACK_PENDING;
                ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
                break;
            }
        }
    }

    if (sk)
        bh_unlock_sock(sk);

    ax25_start_heartbeat(ax25);
}

void ax25_std_t2timer_expiry(ax25_cb *ax25)
{
    if (ax25->condition & AX25_COND_ACK_PENDING) {
        ax25->condition &= ~AX25_COND_ACK_PENDING;
        ax25_std_timeout_response(ax25);
    }
}

void ax25_std_t3timer_expiry(ax25_cb *ax25)
{
    ax25->n2count = 0;
    ax25_std_transmit_enquiry(ax25);
    ax25->state   = AX25_STATE_4;
}

void ax25_std_idletimer_expiry(ax25_cb *ax25)
{
    ax25_clear_queues(ax25);

    ax25->n2count = 0;
    ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
    ax25->state   = AX25_STATE_2;

    ax25_calculate_t1(ax25);
    ax25_start_t1timer(ax25);
    ax25_stop_t2timer(ax25);
    ax25_stop_t3timer(ax25);

    if (ax25->sk != NULL) {
        bh_lock_sock(ax25->sk);
        ax25->sk->sk_state     = TCP_CLOSE;
        ax25->sk->sk_err       = 0;
        ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
        if (!sock_flag(ax25->sk, SOCK_DEAD)) {
            ax25->sk->sk_state_change(ax25->sk);
            sock_set_flag(ax25->sk, SOCK_DEAD);
        }
        bh_unlock_sock(ax25->sk);
    }
}

void ax25_std_t1timer_expiry(ax25_cb *ax25)
{
    switch (ax25->state) {
    case AX25_STATE_1:
        if (ax25->n2count == ax25->n2) {
            if (ax25->modulus == AX25_MODULUS) {
                ax25_disconnect(ax25, ETIMEDOUT);
                return;
            } else {
                ax25->modulus = AX25_MODULUS;
                ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
                ax25->n2count = 0;
                ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
            }
        } else {
            ax25->n2count++;
            if (ax25->modulus == AX25_MODULUS)
                ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
            else
                ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
        }
        break;

    case AX25_STATE_2:
        if (ax25->n2count == ax25->n2) {
            ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
            ax25_disconnect(ax25, ETIMEDOUT);
            return;
        } else {
            ax25->n2count++;
            ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
        }
        break;

    case AX25_STATE_3:
        ax25->n2count = 1;
        ax25_std_transmit_enquiry(ax25);
        ax25->state   = AX25_STATE_4;
        break;

    case AX25_STATE_4:
        if (ax25->n2count == ax25->n2) {
            ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
            ax25_disconnect(ax25, ETIMEDOUT);
            return;
        } else {
            ax25->n2count++;
            ax25_std_transmit_enquiry(ax25);
        }
        break;
    }

    ax25_calculate_t1(ax25);
    ax25_start_t1timer(ax25);
}