// 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);}