// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright (C) Jonathan Naylor G4KLX ([email protected])
* Copyright (C) Joerg Reuter DL1BKE ([email protected])
*/
#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 <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
static void ax25_ds_timeout(struct timer_list *);
/*
* 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.
*/
void ax25_ds_setup_timer(ax25_dev *ax25_dev)
{
timer_setup(&ax25_dev->dama.slave_timer, ax25_ds_timeout, 0);
}
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;
ax25_dev->dama.slave_timeout =
msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
}
/*
* DAMA Slave Timeout
* Silently discard all (slave) connections in case our master forgot us...
*/
static void ax25_ds_timeout(struct timer_list *t)
{
ax25_dev *ax25_dev = from_timer(ax25_dev, t, dama.slave_timer);
ax25_cb *ax25;
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, &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:
case AX25_STATE_2:
/* 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);
/* Ungrab socket and destroy it */
sock_put(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 >> 1) &&
(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);
if (!sock_flag(ax25->sk, SOCK_DESTROY))
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);
}
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