linux/net/ax25/ax25_timer.c
Francois Romieu df1c941468 net: avoid overflow when rose /proc displays timer information.
rose /proc code does not serialize timer accesses.

Initial report by Bernard F6BVP Pidoux exhibits overflow amounting
to 116 ticks on its HZ=250 system.

Full timer access serialization would imho be overkill as rose /proc
does not enforce consistency between displayed ROSE_STATE_XYZ and
timer values during changes of state.

The patch may also fix similar behavior in ax25 /proc, ax25 ioctl
and netrom /proc as they all exhibit the same timer serialization
policy. This point has not been reported though.

The sole remaining use of ax25_display_timer - ax25 rtt valuation -
may also perform marginally better but I have not analyzed it too
deeply.

Cc: Thomas DL9SAU Osterried <thomas@osterried.de>
Link: https://lore.kernel.org/all/d5e93cc7-a91f-13d3-49a1-b50c11f0f811@free.fr/
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Tested-by: Bernard Pidoux <f6bvp@free.fr>
Link: https://lore.kernel.org/r/Yuk9vq7t7VhmnOXu@electric-eye.fr.zoreil.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-05 19:00:02 -07:00

225 lines
4.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
* Copyright (C) Tomi Manninen OH2BNS (oh2bns@sral.fi)
* Copyright (C) Darryl Miles G7LED (dlm@g7led.demon.co.uk)
* Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
* Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
* Copyright (C) 2002 Ralf Baechle DO1GRB (ralf@gnu.org)
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/jiffies.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 <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
static void ax25_heartbeat_expiry(struct timer_list *);
static void ax25_t1timer_expiry(struct timer_list *);
static void ax25_t2timer_expiry(struct timer_list *);
static void ax25_t3timer_expiry(struct timer_list *);
static void ax25_idletimer_expiry(struct timer_list *);
void ax25_setup_timers(ax25_cb *ax25)
{
timer_setup(&ax25->timer, ax25_heartbeat_expiry, 0);
timer_setup(&ax25->t1timer, ax25_t1timer_expiry, 0);
timer_setup(&ax25->t2timer, ax25_t2timer_expiry, 0);
timer_setup(&ax25->t3timer, ax25_t3timer_expiry, 0);
timer_setup(&ax25->idletimer, ax25_idletimer_expiry, 0);
}
void ax25_start_heartbeat(ax25_cb *ax25)
{
mod_timer(&ax25->timer, jiffies + 5 * HZ);
}
void ax25_start_t1timer(ax25_cb *ax25)
{
mod_timer(&ax25->t1timer, jiffies + ax25->t1);
}
void ax25_start_t2timer(ax25_cb *ax25)
{
mod_timer(&ax25->t2timer, jiffies + ax25->t2);
}
void ax25_start_t3timer(ax25_cb *ax25)
{
if (ax25->t3 > 0)
mod_timer(&ax25->t3timer, jiffies + ax25->t3);
else
del_timer(&ax25->t3timer);
}
void ax25_start_idletimer(ax25_cb *ax25)
{
if (ax25->idle > 0)
mod_timer(&ax25->idletimer, jiffies + ax25->idle);
else
del_timer(&ax25->idletimer);
}
void ax25_stop_heartbeat(ax25_cb *ax25)
{
del_timer(&ax25->timer);
}
void ax25_stop_t1timer(ax25_cb *ax25)
{
del_timer(&ax25->t1timer);
}
void ax25_stop_t2timer(ax25_cb *ax25)
{
del_timer(&ax25->t2timer);
}
void ax25_stop_t3timer(ax25_cb *ax25)
{
del_timer(&ax25->t3timer);
}
void ax25_stop_idletimer(ax25_cb *ax25)
{
del_timer(&ax25->idletimer);
}
int ax25_t1timer_running(ax25_cb *ax25)
{
return timer_pending(&ax25->t1timer);
}
unsigned long ax25_display_timer(struct timer_list *timer)
{
long delta = timer->expires - jiffies;
if (!timer_pending(timer))
return 0;
return max(0L, delta);
}
EXPORT_SYMBOL(ax25_display_timer);
static void ax25_heartbeat_expiry(struct timer_list *t)
{
int proto = AX25_PROTO_STD_SIMPLEX;
ax25_cb *ax25 = from_timer(ax25, t, timer);
if (ax25->ax25_dev)
proto = ax25->ax25_dev->values[AX25_VALUES_PROTOCOL];
switch (proto) {
case AX25_PROTO_STD_SIMPLEX:
case AX25_PROTO_STD_DUPLEX:
ax25_std_heartbeat_expiry(ax25);
break;
#ifdef CONFIG_AX25_DAMA_SLAVE
case AX25_PROTO_DAMA_SLAVE:
if (ax25->ax25_dev->dama.slave)
ax25_ds_heartbeat_expiry(ax25);
else
ax25_std_heartbeat_expiry(ax25);
break;
#endif
}
}
static void ax25_t1timer_expiry(struct timer_list *t)
{
ax25_cb *ax25 = from_timer(ax25, t, t1timer);
switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
case AX25_PROTO_STD_SIMPLEX:
case AX25_PROTO_STD_DUPLEX:
ax25_std_t1timer_expiry(ax25);
break;
#ifdef CONFIG_AX25_DAMA_SLAVE
case AX25_PROTO_DAMA_SLAVE:
if (!ax25->ax25_dev->dama.slave)
ax25_std_t1timer_expiry(ax25);
break;
#endif
}
}
static void ax25_t2timer_expiry(struct timer_list *t)
{
ax25_cb *ax25 = from_timer(ax25, t, t2timer);
switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
case AX25_PROTO_STD_SIMPLEX:
case AX25_PROTO_STD_DUPLEX:
ax25_std_t2timer_expiry(ax25);
break;
#ifdef CONFIG_AX25_DAMA_SLAVE
case AX25_PROTO_DAMA_SLAVE:
if (!ax25->ax25_dev->dama.slave)
ax25_std_t2timer_expiry(ax25);
break;
#endif
}
}
static void ax25_t3timer_expiry(struct timer_list *t)
{
ax25_cb *ax25 = from_timer(ax25, t, t3timer);
switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
case AX25_PROTO_STD_SIMPLEX:
case AX25_PROTO_STD_DUPLEX:
ax25_std_t3timer_expiry(ax25);
break;
#ifdef CONFIG_AX25_DAMA_SLAVE
case AX25_PROTO_DAMA_SLAVE:
if (ax25->ax25_dev->dama.slave)
ax25_ds_t3timer_expiry(ax25);
else
ax25_std_t3timer_expiry(ax25);
break;
#endif
}
}
static void ax25_idletimer_expiry(struct timer_list *t)
{
ax25_cb *ax25 = from_timer(ax25, t, idletimer);
switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
case AX25_PROTO_STD_SIMPLEX:
case AX25_PROTO_STD_DUPLEX:
ax25_std_idletimer_expiry(ax25);
break;
#ifdef CONFIG_AX25_DAMA_SLAVE
case AX25_PROTO_DAMA_SLAVE:
if (ax25->ax25_dev->dama.slave)
ax25_ds_idletimer_expiry(ax25);
else
ax25_std_idletimer_expiry(ax25);
break;
#endif
}
}