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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 (g4klx@g4klx.demon.co.uk)

 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)

 */

#include <linux/errno.h>

#include <linux/types.h>

#include <linux/socket.h>

#include <linux/spinlock.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/tcp_states.h>

#include <net/ax25.h>

#include <linux/inet.h>

#include <linux/netdevice.h>

#include <linux/skbuff.h>

#include <net/sock.h>

#include <asm/uaccess.h>

#include <asm/system.h>

#include <linux/fcntl.h>

#include <linux/mm.h>

#include <linux/interrupt.h>

static void ax25_ds_timeout(unsigned long);

/*

 *      Add DAMA slave timeout timer to timer list.

 *      Unlike the connection based timers the timeout function gets

 *      triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT

 *      (aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in

 *      1/10th of a second.

 */

static void ax25_ds_add_timer(ax25_dev *ax25_dev)

{

        struct timer_list *t = &ax25_dev->dama.slave_timer;

        t->data         = (unsigned long) ax25_dev;

        t->function     = &ax25_ds_timeout;

        t->expires      = jiffies + HZ;

        add_timer(t);

}

void ax25_ds_del_timer(ax25_dev *ax25_dev)

{

        if (ax25_dev)

                del_timer(&ax25_dev->dama.slave_timer);

}

void ax25_ds_set_timer(ax25_dev *ax25_dev)

{

        if (ax25_dev == NULL)           /* paranoia */

                return;

        del_timer(&ax25_dev->dama.slave_timer);

        ax25_dev->dama.slave_timeout =

                msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;

        ax25_ds_add_timer(ax25_dev);

}

/*

 *      DAMA Slave Timeout

 *      Silently discard all (slave) connections in case our master forgot us...

 */

static void ax25_ds_timeout(unsigned long arg)

{

        ax25_dev *ax25_dev = (struct ax25_dev *) arg;

        ax25_cb *ax25;

        struct hlist_node *node;

        if (ax25_dev == NULL || !ax25_dev->dama.slave)

                return;                 /* Yikes! */

        if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {

                ax25_ds_set_timer(ax25_dev);

                return;

        }

        spin_lock(&ax25_list_lock);

        ax25_for_each(ax25, node, &ax25_list) {

                if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))

                        continue;

                ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);

                ax25_disconnect(ax25, ETIMEDOUT);

        }

        spin_unlock(&ax25_list_lock);

        ax25_dev_dama_off(ax25_dev);

}

void ax25_ds_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);

                                sock_put(sk);

                                bh_unlock_sock(sk);

                        } else

                                ax25_destroy_socket(ax25);

                        return;

                }

                break;

        case AX25_STATE_3:

                /*

                 * Check the state of the receive buffer.

                 */

                if (sk != NULL) {

                        if (atomic_read(&sk->sk_rmem_alloc) <

                            (sk->sk_rcvbuf / 2) &&

                            (ax25->condition & AX25_COND_OWN_RX_BUSY)) {

                                ax25->condition &= ~AX25_COND_OWN_RX_BUSY;

                                ax25->condition &= ~AX25_COND_ACK_PENDING;

                                break;

                        }

                }

                break;

        }

        if (sk)

                bh_unlock_sock(sk);

        ax25_start_heartbeat(ax25);

}

/* dl1bke 960114: T3 works much like the IDLE timeout, but

 *                gets reloaded with every frame for this

 *                connection.

 */

void ax25_ds_t3timer_expiry(ax25_cb *ax25)

{

        ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);

        ax25_dama_off(ax25);

        ax25_disconnect(ax25, ETIMEDOUT);

}

/* dl1bke 960228: close the connection when IDLE expires.

 *                unlike T3 this timer gets reloaded only on

 *                I frames.

 */

void ax25_ds_idletimer_expiry(ax25_cb *ax25)

{

        ax25_clear_queues(ax25);

        ax25->n2count = 0;

        ax25->state = AX25_STATE_2;

        ax25_calculate_t1(ax25);

        ax25_start_t1timer(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);

        }

}

/* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC

 *                within the poll of any connected channel. Remember

 *                that we are not allowed to send anything unless we

 *                get polled by the Master.

 *

 *                Thus we'll have to do parts of our T1 handling in

 *                ax25_enquiry_response().

 */

void ax25_ds_t1_timeout(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_POLLOFF, AX25_COMMAND);

                        }

                } else {

                        ax25->n2count++;

                        if (ax25->modulus == AX25_MODULUS)

                                ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);

                        else

                                ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, 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++;

                }

                break;

        case AX25_STATE_3:

                if (ax25->n2count == ax25->n2) {

                        ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);

                        ax25_disconnect(ax25, ETIMEDOUT);

                        return;

                } else {

                        ax25->n2count++;

                }

                break;

        }

        ax25_calculate_t1(ax25);

        ax25_start_t1timer(ax25);

}