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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* LAPB release 002
*
* This code REQUIRES 2.1.15 or higher/ NET3.038
*
* History
* LAPB 001 Jonathan Naylor Started Coding
* LAPB 002 Jonathan Naylor New timer architecture.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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 <linux/inet.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>
#include <net/lapb.h>
static void lapb_t1timer_expiry(struct timer_list *);
static void lapb_t2timer_expiry(struct timer_list *);
void lapb_start_t1timer(struct lapb_cb *lapb)
{
del_timer(&lapb->t1timer);
lapb->t1timer.function = lapb_t1timer_expiry;
lapb->t1timer.expires = jiffies + lapb->t1;
lapb->t1timer_running = true;
add_timer(&lapb->t1timer);
}
void lapb_start_t2timer(struct lapb_cb *lapb)
{
del_timer(&lapb->t2timer);
lapb->t2timer.function = lapb_t2timer_expiry;
lapb->t2timer.expires = jiffies + lapb->t2;
lapb->t2timer_running = true;
add_timer(&lapb->t2timer);
}
void lapb_stop_t1timer(struct lapb_cb *lapb)
{
lapb->t1timer_running = false;
del_timer(&lapb->t1timer);
}
void lapb_stop_t2timer(struct lapb_cb *lapb)
{
lapb->t2timer_running = false;
del_timer(&lapb->t2timer);
}
int lapb_t1timer_running(struct lapb_cb *lapb)
{
return lapb->t1timer_running;
}
static void lapb_t2timer_expiry(struct timer_list *t)
{
struct lapb_cb *lapb = from_timer(lapb, t, t2timer);
spin_lock_bh(&lapb->lock);
if (timer_pending(&lapb->t2timer)) /* A new timer has been set up */
goto out;
if (!lapb->t2timer_running) /* The timer has been stopped */
goto out;
if (lapb->condition & LAPB_ACK_PENDING_CONDITION) {
lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
lapb_timeout_response(lapb);
}
lapb->t2timer_running = false;
out:
spin_unlock_bh(&lapb->lock);
}
static void lapb_t1timer_expiry(struct timer_list *t)
{
struct lapb_cb *lapb = from_timer(lapb, t, t1timer);
spin_lock_bh(&lapb->lock);
if (timer_pending(&lapb->t1timer)) /* A new timer has been set up */
goto out;
if (!lapb->t1timer_running) /* The timer has been stopped */
goto out;
switch (lapb->state) {
/*
* If we are a DCE, send DM up to N2 times, then switch to
* STATE_1 and send SABM(E).
*/
case LAPB_STATE_0:
if (lapb->mode & LAPB_DCE &&
lapb->n2count != lapb->n2) {
lapb->n2count++;
lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
} else {
lapb->state = LAPB_STATE_1;
lapb_establish_data_link(lapb);
}
break;
/*
* Awaiting connection state, send SABM(E), up to N2 times.
*/
case LAPB_STATE_1:
if (lapb->n2count == lapb->n2) {
lapb_clear_queues(lapb);
lapb->state = LAPB_STATE_0;
lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
lapb->t1timer_running = false;
goto out;
} else {
lapb->n2count++;
if (lapb->mode & LAPB_EXTENDED) {
lapb_dbg(1, "(%p) S1 TX SABME(1)\n",
lapb->dev);
lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
} else {
lapb_dbg(1, "(%p) S1 TX SABM(1)\n",
lapb->dev);
lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
}
}
break;
/*
* Awaiting disconnection state, send DISC, up to N2 times.
*/
case LAPB_STATE_2:
if (lapb->n2count == lapb->n2) {
lapb_clear_queues(lapb);
lapb->state = LAPB_STATE_0;
lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT);
lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
lapb->t1timer_running = false;
goto out;
} else {
lapb->n2count++;
lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev);
lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
}
break;
/*
* Data transfer state, restransmit I frames, up to N2 times.
*/
case LAPB_STATE_3:
if (lapb->n2count == lapb->n2) {
lapb_clear_queues(lapb);
lapb->state = LAPB_STATE_0;
lapb_stop_t2timer(lapb);
lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
lapb->t1timer_running = false;
goto out;
} else {
lapb->n2count++;
lapb_requeue_frames(lapb);
lapb_kick(lapb);
}
break;
/*
* Frame reject state, restransmit FRMR frames, up to N2 times.
*/
case LAPB_STATE_4:
if (lapb->n2count == lapb->n2) {
lapb_clear_queues(lapb);
lapb->state = LAPB_STATE_0;
lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev);
lapb->t1timer_running = false;
goto out;
} else {
lapb->n2count++;
lapb_transmit_frmr(lapb);
}
break;
}
lapb_start_t1timer(lapb);
out:
spin_unlock_bh(&lapb->lock);
}
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