mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Eric Dumazet](/assets/img/avatar_default.png)
We got another syzbot report [1] that tells us we must use
write_lock_irq()/write_unlock_irq() to avoid possible deadlock.
[1]
WARNING: inconsistent lock state
5.5.0-rc1-syzkaller #0 Not tainted
--------------------------------
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-R} usage.
syz-executor826/9605 [HC1[1]:SC0[0]:HE0:SE1] takes:
ffffffff8a128718 (disc_data_lock){+-..}, at: sp_get.isra.0+0x1d/0xf0 drivers/net/ppp/ppp_synctty.c:138
{HARDIRQ-ON-W} state was registered at:
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485
__raw_write_lock_bh include/linux/rwlock_api_smp.h:203 [inline]
_raw_write_lock_bh+0x33/0x50 kernel/locking/spinlock.c:319
sixpack_close+0x1d/0x250 drivers/net/hamradio/6pack.c:657
tty_ldisc_close.isra.0+0x119/0x1a0 drivers/tty/tty_ldisc.c:489
tty_set_ldisc+0x230/0x6b0 drivers/tty/tty_ldisc.c:585
tiocsetd drivers/tty/tty_io.c:2337 [inline]
tty_ioctl+0xe8d/0x14f0 drivers/tty/tty_io.c:2597
vfs_ioctl fs/ioctl.c:47 [inline]
file_ioctl fs/ioctl.c:545 [inline]
do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732
ksys_ioctl+0xab/0xd0 fs/ioctl.c:749
__do_sys_ioctl fs/ioctl.c:756 [inline]
__se_sys_ioctl fs/ioctl.c:754 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
irq event stamp: 3946
hardirqs last enabled at (3945): [<ffffffff87c86e43>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
hardirqs last enabled at (3945): [<ffffffff87c86e43>] _raw_spin_unlock_irq+0x23/0x80 kernel/locking/spinlock.c:199
hardirqs last disabled at (3946): [<ffffffff8100675f>] trace_hardirqs_off_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:42
softirqs last enabled at (2658): [<ffffffff86a8b4df>] spin_unlock_bh include/linux/spinlock.h:383 [inline]
softirqs last enabled at (2658): [<ffffffff86a8b4df>] clusterip_netdev_event+0x46f/0x670 net/ipv4/netfilter/ipt_CLUSTERIP.c:222
softirqs last disabled at (2656): [<ffffffff86a8b22b>] spin_lock_bh include/linux/spinlock.h:343 [inline]
softirqs last disabled at (2656): [<ffffffff86a8b22b>] clusterip_netdev_event+0x1bb/0x670 net/ipv4/netfilter/ipt_CLUSTERIP.c:196
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(disc_data_lock);
<Interrupt>
lock(disc_data_lock);
*** DEADLOCK ***
5 locks held by syz-executor826/9605:
#0: ffff8880a905e198 (&tty->legacy_mutex){+.+.}, at: tty_lock+0xc7/0x130 drivers/tty/tty_mutex.c:19
#1: ffffffff899a56c0 (rcu_read_lock){....}, at: mutex_spin_on_owner+0x0/0x330 kernel/locking/mutex.c:413
#2: ffff8880a496a2b0 (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:338 [inline]
#2: ffff8880a496a2b0 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x2d/0x1a0 drivers/tty/serial/8250/8250_core.c:116
#3: ffffffff8c104048 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x24/0x330 drivers/tty/serial/8250/8250_port.c:1823
#4: ffff8880a905e090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x22/0x90 drivers/tty/tty_ldisc.c:288
stack backtrace:
CPU: 1 PID: 9605 Comm: syz-executor826 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
print_usage_bug.cold+0x327/0x378 kernel/locking/lockdep.c:3101
valid_state kernel/locking/lockdep.c:3112 [inline]
mark_lock_irq kernel/locking/lockdep.c:3309 [inline]
mark_lock+0xbb4/0x1220 kernel/locking/lockdep.c:3666
mark_usage kernel/locking/lockdep.c:3554 [inline]
__lock_acquire+0x1e55/0x4a00 kernel/locking/lockdep.c:3909
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485
__raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
_raw_read_lock+0x32/0x50 kernel/locking/spinlock.c:223
sp_get.isra.0+0x1d/0xf0 drivers/net/ppp/ppp_synctty.c:138
sixpack_write_wakeup+0x25/0x340 drivers/net/hamradio/6pack.c:402
tty_wakeup+0xe9/0x120 drivers/tty/tty_io.c:536
tty_port_default_wakeup+0x2b/0x40 drivers/tty/tty_port.c:50
tty_port_tty_wakeup+0x57/0x70 drivers/tty/tty_port.c:387
uart_write_wakeup+0x46/0x70 drivers/tty/serial/serial_core.c:104
serial8250_tx_chars+0x495/0xaf0 drivers/tty/serial/8250/8250_port.c:1761
serial8250_handle_irq.part.0+0x2a2/0x330 drivers/tty/serial/8250/8250_port.c:1834
serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1820 [inline]
serial8250_default_handle_irq+0xc0/0x150 drivers/tty/serial/8250/8250_port.c:1850
serial8250_interrupt+0xf1/0x1a0 drivers/tty/serial/8250/8250_core.c:126
__handle_irq_event_percpu+0x15d/0x970 kernel/irq/handle.c:149
handle_irq_event_percpu+0x74/0x160 kernel/irq/handle.c:189
handle_irq_event+0xa7/0x134 kernel/irq/handle.c:206
handle_edge_irq+0x25e/0x8d0 kernel/irq/chip.c:830
generic_handle_irq_desc include/linux/irqdesc.h:156 [inline]
do_IRQ+0xde/0x280 arch/x86/kernel/irq.c:250
common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:607
</IRQ>
RIP: 0010:cpu_relax arch/x86/include/asm/processor.h:685 [inline]
RIP: 0010:mutex_spin_on_owner+0x247/0x330 kernel/locking/mutex.c:579
Code: c3 be 08 00 00 00 4c 89 e7 e8 e5 06 59 00 4c 89 e0 48 c1 e8 03 42 80 3c 38 00 0f 85 e1 00 00 00 49 8b 04 24 a8 01 75 96 f3 90 <e9> 2f fe ff ff 0f 0b e8 0d 19 09 00 84 c0 0f 85 ff fd ff ff 48 c7
RSP: 0018:ffffc90001eafa20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffd7
RAX: 0000000000000000 RBX: ffff88809fd9e0c0 RCX: 1ffffffff13266dd
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000000
RBP: ffffc90001eafa60 R08: 1ffff11013d22898 R09: ffffed1013d22899
R10: ffffed1013d22898 R11: ffff88809e9144c7 R12: ffff8880a905e138
R13: ffff88809e9144c0 R14: 0000000000000000 R15: dffffc0000000000
mutex_optimistic_spin kernel/locking/mutex.c:673 [inline]
__mutex_lock_common kernel/locking/mutex.c:962 [inline]
__mutex_lock+0x32b/0x13c0 kernel/locking/mutex.c:1106
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121
tty_lock+0xc7/0x130 drivers/tty/tty_mutex.c:19
tty_release+0xb5/0xe90 drivers/tty/tty_io.c:1665
__fput+0x2ff/0x890 fs/file_table.c:280
____fput+0x16/0x20 fs/file_table.c:313
task_work_run+0x145/0x1c0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x8e7/0x2ef0 kernel/exit.c:797
do_group_exit+0x135/0x360 kernel/exit.c:895
__do_sys_exit_group kernel/exit.c:906 [inline]
__se_sys_exit_group kernel/exit.c:904 [inline]
__x64_sys_exit_group+0x44/0x50 kernel/exit.c:904
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x43fef8
Code: Bad RIP value.
RSP: 002b:00007ffdb07d2338 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043fef8
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004bf730 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d1180 R14: 0000000000000000 R15: 0000000000000000
Fixes: 6e4e2f811b
("6pack,mkiss: fix lock inconsistency")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
983 lines
23 KiB
C
983 lines
23 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
*
|
|
* Copyright (C) Hans Alblas PE1AYX <hans@esrac.ele.tue.nl>
|
|
* Copyright (C) 2004, 05 Ralf Baechle DL5RB <ralf@linux-mips.org>
|
|
* Copyright (C) 2004, 05 Thomas Osterried DL9SAU <thomas@x-berg.in-berlin.de>
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/crc16.h>
|
|
#include <linux/string.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/in.h>
|
|
#include <linux/inet.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/tty.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/netdevice.h>
|
|
#include <linux/major.h>
|
|
#include <linux/init.h>
|
|
#include <linux/rtnetlink.h>
|
|
#include <linux/etherdevice.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/if_arp.h>
|
|
#include <linux/jiffies.h>
|
|
#include <linux/refcount.h>
|
|
|
|
#include <net/ax25.h>
|
|
|
|
#define AX_MTU 236
|
|
|
|
/* SLIP/KISS protocol characters. */
|
|
#define END 0300 /* indicates end of frame */
|
|
#define ESC 0333 /* indicates byte stuffing */
|
|
#define ESC_END 0334 /* ESC ESC_END means END 'data' */
|
|
#define ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */
|
|
|
|
struct mkiss {
|
|
struct tty_struct *tty; /* ptr to TTY structure */
|
|
struct net_device *dev; /* easy for intr handling */
|
|
|
|
/* These are pointers to the malloc()ed frame buffers. */
|
|
spinlock_t buflock;/* lock for rbuf and xbuf */
|
|
unsigned char *rbuff; /* receiver buffer */
|
|
int rcount; /* received chars counter */
|
|
unsigned char *xbuff; /* transmitter buffer */
|
|
unsigned char *xhead; /* pointer to next byte to XMIT */
|
|
int xleft; /* bytes left in XMIT queue */
|
|
|
|
/* Detailed SLIP statistics. */
|
|
int mtu; /* Our mtu (to spot changes!) */
|
|
int buffsize; /* Max buffers sizes */
|
|
|
|
unsigned long flags; /* Flag values/ mode etc */
|
|
/* long req'd: used by set_bit --RR */
|
|
#define AXF_INUSE 0 /* Channel in use */
|
|
#define AXF_ESCAPE 1 /* ESC received */
|
|
#define AXF_ERROR 2 /* Parity, etc. error */
|
|
#define AXF_KEEPTEST 3 /* Keepalive test flag */
|
|
#define AXF_OUTWAIT 4 /* is outpacket was flag */
|
|
|
|
int mode;
|
|
int crcmode; /* MW: for FlexNet, SMACK etc. */
|
|
int crcauto; /* CRC auto mode */
|
|
|
|
#define CRC_MODE_NONE 0
|
|
#define CRC_MODE_FLEX 1
|
|
#define CRC_MODE_SMACK 2
|
|
#define CRC_MODE_FLEX_TEST 3
|
|
#define CRC_MODE_SMACK_TEST 4
|
|
|
|
refcount_t refcnt;
|
|
struct completion dead;
|
|
};
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
static const unsigned short crc_flex_table[] = {
|
|
0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38,
|
|
0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770,
|
|
0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9,
|
|
0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1,
|
|
0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a,
|
|
0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672,
|
|
0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb,
|
|
0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3,
|
|
0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c,
|
|
0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574,
|
|
0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd,
|
|
0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5,
|
|
0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e,
|
|
0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476,
|
|
0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf,
|
|
0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7,
|
|
0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30,
|
|
0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378,
|
|
0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1,
|
|
0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9,
|
|
0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32,
|
|
0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a,
|
|
0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3,
|
|
0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb,
|
|
0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34,
|
|
0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c,
|
|
0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5,
|
|
0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd,
|
|
0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36,
|
|
0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e,
|
|
0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7,
|
|
0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff
|
|
};
|
|
|
|
static unsigned short calc_crc_flex(unsigned char *cp, int size)
|
|
{
|
|
unsigned short crc = 0xffff;
|
|
|
|
while (size--)
|
|
crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
|
|
|
|
return crc;
|
|
}
|
|
|
|
static int check_crc_flex(unsigned char *cp, int size)
|
|
{
|
|
unsigned short crc = 0xffff;
|
|
|
|
if (size < 3)
|
|
return -1;
|
|
|
|
while (size--)
|
|
crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
|
|
|
|
if ((crc & 0xffff) != 0x7070)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int check_crc_16(unsigned char *cp, int size)
|
|
{
|
|
unsigned short crc = 0x0000;
|
|
|
|
if (size < 3)
|
|
return -1;
|
|
|
|
crc = crc16(0, cp, size);
|
|
|
|
if (crc != 0x0000)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Standard encapsulation
|
|
*/
|
|
|
|
static int kiss_esc(unsigned char *s, unsigned char *d, int len)
|
|
{
|
|
unsigned char *ptr = d;
|
|
unsigned char c;
|
|
|
|
/*
|
|
* Send an initial END character to flush out any data that may have
|
|
* accumulated in the receiver due to line noise.
|
|
*/
|
|
|
|
*ptr++ = END;
|
|
|
|
while (len-- > 0) {
|
|
switch (c = *s++) {
|
|
case END:
|
|
*ptr++ = ESC;
|
|
*ptr++ = ESC_END;
|
|
break;
|
|
case ESC:
|
|
*ptr++ = ESC;
|
|
*ptr++ = ESC_ESC;
|
|
break;
|
|
default:
|
|
*ptr++ = c;
|
|
break;
|
|
}
|
|
}
|
|
|
|
*ptr++ = END;
|
|
|
|
return ptr - d;
|
|
}
|
|
|
|
/*
|
|
* MW:
|
|
* OK its ugly, but tell me a better solution without copying the
|
|
* packet to a temporary buffer :-)
|
|
*/
|
|
static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc,
|
|
int len)
|
|
{
|
|
unsigned char *ptr = d;
|
|
unsigned char c=0;
|
|
|
|
*ptr++ = END;
|
|
while (len > 0) {
|
|
if (len > 2)
|
|
c = *s++;
|
|
else if (len > 1)
|
|
c = crc >> 8;
|
|
else
|
|
c = crc & 0xff;
|
|
|
|
len--;
|
|
|
|
switch (c) {
|
|
case END:
|
|
*ptr++ = ESC;
|
|
*ptr++ = ESC_END;
|
|
break;
|
|
case ESC:
|
|
*ptr++ = ESC;
|
|
*ptr++ = ESC_ESC;
|
|
break;
|
|
default:
|
|
*ptr++ = c;
|
|
break;
|
|
}
|
|
}
|
|
*ptr++ = END;
|
|
|
|
return ptr - d;
|
|
}
|
|
|
|
/* Send one completely decapsulated AX.25 packet to the AX.25 layer. */
|
|
static void ax_bump(struct mkiss *ax)
|
|
{
|
|
struct sk_buff *skb;
|
|
int count;
|
|
|
|
spin_lock_bh(&ax->buflock);
|
|
if (ax->rbuff[0] > 0x0f) {
|
|
if (ax->rbuff[0] & 0x80) {
|
|
if (check_crc_16(ax->rbuff, ax->rcount) < 0) {
|
|
ax->dev->stats.rx_errors++;
|
|
spin_unlock_bh(&ax->buflock);
|
|
|
|
return;
|
|
}
|
|
if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) {
|
|
printk(KERN_INFO
|
|
"mkiss: %s: Switching to crc-smack\n",
|
|
ax->dev->name);
|
|
ax->crcmode = CRC_MODE_SMACK;
|
|
}
|
|
ax->rcount -= 2;
|
|
*ax->rbuff &= ~0x80;
|
|
} else if (ax->rbuff[0] & 0x20) {
|
|
if (check_crc_flex(ax->rbuff, ax->rcount) < 0) {
|
|
ax->dev->stats.rx_errors++;
|
|
spin_unlock_bh(&ax->buflock);
|
|
return;
|
|
}
|
|
if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) {
|
|
printk(KERN_INFO
|
|
"mkiss: %s: Switching to crc-flexnet\n",
|
|
ax->dev->name);
|
|
ax->crcmode = CRC_MODE_FLEX;
|
|
}
|
|
ax->rcount -= 2;
|
|
|
|
/*
|
|
* dl9sau bugfix: the trailling two bytes flexnet crc
|
|
* will not be passed to the kernel. thus we have to
|
|
* correct the kissparm signature, because it indicates
|
|
* a crc but there's none
|
|
*/
|
|
*ax->rbuff &= ~0x20;
|
|
}
|
|
}
|
|
|
|
count = ax->rcount;
|
|
|
|
if ((skb = dev_alloc_skb(count)) == NULL) {
|
|
printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n",
|
|
ax->dev->name);
|
|
ax->dev->stats.rx_dropped++;
|
|
spin_unlock_bh(&ax->buflock);
|
|
return;
|
|
}
|
|
|
|
skb_put_data(skb, ax->rbuff, count);
|
|
skb->protocol = ax25_type_trans(skb, ax->dev);
|
|
netif_rx(skb);
|
|
ax->dev->stats.rx_packets++;
|
|
ax->dev->stats.rx_bytes += count;
|
|
spin_unlock_bh(&ax->buflock);
|
|
}
|
|
|
|
static void kiss_unesc(struct mkiss *ax, unsigned char s)
|
|
{
|
|
switch (s) {
|
|
case END:
|
|
/* drop keeptest bit = VSV */
|
|
if (test_bit(AXF_KEEPTEST, &ax->flags))
|
|
clear_bit(AXF_KEEPTEST, &ax->flags);
|
|
|
|
if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2))
|
|
ax_bump(ax);
|
|
|
|
clear_bit(AXF_ESCAPE, &ax->flags);
|
|
ax->rcount = 0;
|
|
return;
|
|
|
|
case ESC:
|
|
set_bit(AXF_ESCAPE, &ax->flags);
|
|
return;
|
|
case ESC_ESC:
|
|
if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
|
|
s = ESC;
|
|
break;
|
|
case ESC_END:
|
|
if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
|
|
s = END;
|
|
break;
|
|
}
|
|
|
|
spin_lock_bh(&ax->buflock);
|
|
if (!test_bit(AXF_ERROR, &ax->flags)) {
|
|
if (ax->rcount < ax->buffsize) {
|
|
ax->rbuff[ax->rcount++] = s;
|
|
spin_unlock_bh(&ax->buflock);
|
|
return;
|
|
}
|
|
|
|
ax->dev->stats.rx_over_errors++;
|
|
set_bit(AXF_ERROR, &ax->flags);
|
|
}
|
|
spin_unlock_bh(&ax->buflock);
|
|
}
|
|
|
|
static int ax_set_mac_address(struct net_device *dev, void *addr)
|
|
{
|
|
struct sockaddr_ax25 *sa = addr;
|
|
|
|
netif_tx_lock_bh(dev);
|
|
netif_addr_lock(dev);
|
|
memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
|
|
netif_addr_unlock(dev);
|
|
netif_tx_unlock_bh(dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
static void ax_changedmtu(struct mkiss *ax)
|
|
{
|
|
struct net_device *dev = ax->dev;
|
|
unsigned char *xbuff, *rbuff, *oxbuff, *orbuff;
|
|
int len;
|
|
|
|
len = dev->mtu * 2;
|
|
|
|
/*
|
|
* allow for arrival of larger UDP packets, even if we say not to
|
|
* also fixes a bug in which SunOS sends 512-byte packets even with
|
|
* an MSS of 128
|
|
*/
|
|
if (len < 576 * 2)
|
|
len = 576 * 2;
|
|
|
|
xbuff = kmalloc(len + 4, GFP_ATOMIC);
|
|
rbuff = kmalloc(len + 4, GFP_ATOMIC);
|
|
|
|
if (xbuff == NULL || rbuff == NULL) {
|
|
printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, "
|
|
"MTU change cancelled.\n",
|
|
ax->dev->name);
|
|
dev->mtu = ax->mtu;
|
|
kfree(xbuff);
|
|
kfree(rbuff);
|
|
return;
|
|
}
|
|
|
|
spin_lock_bh(&ax->buflock);
|
|
|
|
oxbuff = ax->xbuff;
|
|
ax->xbuff = xbuff;
|
|
orbuff = ax->rbuff;
|
|
ax->rbuff = rbuff;
|
|
|
|
if (ax->xleft) {
|
|
if (ax->xleft <= len) {
|
|
memcpy(ax->xbuff, ax->xhead, ax->xleft);
|
|
} else {
|
|
ax->xleft = 0;
|
|
dev->stats.tx_dropped++;
|
|
}
|
|
}
|
|
|
|
ax->xhead = ax->xbuff;
|
|
|
|
if (ax->rcount) {
|
|
if (ax->rcount <= len) {
|
|
memcpy(ax->rbuff, orbuff, ax->rcount);
|
|
} else {
|
|
ax->rcount = 0;
|
|
dev->stats.rx_over_errors++;
|
|
set_bit(AXF_ERROR, &ax->flags);
|
|
}
|
|
}
|
|
|
|
ax->mtu = dev->mtu + 73;
|
|
ax->buffsize = len;
|
|
|
|
spin_unlock_bh(&ax->buflock);
|
|
|
|
kfree(oxbuff);
|
|
kfree(orbuff);
|
|
}
|
|
|
|
/* Encapsulate one AX.25 packet and stuff into a TTY queue. */
|
|
static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
|
|
{
|
|
struct mkiss *ax = netdev_priv(dev);
|
|
unsigned char *p;
|
|
int actual, count;
|
|
|
|
if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */
|
|
ax_changedmtu(ax);
|
|
|
|
if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */
|
|
printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name);
|
|
dev->stats.tx_dropped++;
|
|
netif_start_queue(dev);
|
|
return;
|
|
}
|
|
|
|
p = icp;
|
|
|
|
spin_lock_bh(&ax->buflock);
|
|
if ((*p & 0x0f) != 0) {
|
|
/* Configuration Command (kissparms(1).
|
|
* Protocol spec says: never append CRC.
|
|
* This fixes a very old bug in the linux
|
|
* kiss driver. -- dl9sau */
|
|
switch (*p & 0xff) {
|
|
case 0x85:
|
|
/* command from userspace especially for us,
|
|
* not for delivery to the tnc */
|
|
if (len > 1) {
|
|
int cmd = (p[1] & 0xff);
|
|
switch(cmd) {
|
|
case 3:
|
|
ax->crcmode = CRC_MODE_SMACK;
|
|
break;
|
|
case 2:
|
|
ax->crcmode = CRC_MODE_FLEX;
|
|
break;
|
|
case 1:
|
|
ax->crcmode = CRC_MODE_NONE;
|
|
break;
|
|
case 0:
|
|
default:
|
|
ax->crcmode = CRC_MODE_SMACK_TEST;
|
|
cmd = 0;
|
|
}
|
|
ax->crcauto = (cmd ? 0 : 1);
|
|
printk(KERN_INFO "mkiss: %s: crc mode set to %d\n",
|
|
ax->dev->name, cmd);
|
|
}
|
|
spin_unlock_bh(&ax->buflock);
|
|
netif_start_queue(dev);
|
|
|
|
return;
|
|
default:
|
|
count = kiss_esc(p, ax->xbuff, len);
|
|
}
|
|
} else {
|
|
unsigned short crc;
|
|
switch (ax->crcmode) {
|
|
case CRC_MODE_SMACK_TEST:
|
|
ax->crcmode = CRC_MODE_FLEX_TEST;
|
|
printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name);
|
|
// fall through
|
|
case CRC_MODE_SMACK:
|
|
*p |= 0x80;
|
|
crc = swab16(crc16(0, p, len));
|
|
count = kiss_esc_crc(p, ax->xbuff, crc, len+2);
|
|
break;
|
|
case CRC_MODE_FLEX_TEST:
|
|
ax->crcmode = CRC_MODE_NONE;
|
|
printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name);
|
|
// fall through
|
|
case CRC_MODE_FLEX:
|
|
*p |= 0x20;
|
|
crc = calc_crc_flex(p, len);
|
|
count = kiss_esc_crc(p, ax->xbuff, crc, len+2);
|
|
break;
|
|
|
|
default:
|
|
count = kiss_esc(p, ax->xbuff, len);
|
|
}
|
|
}
|
|
spin_unlock_bh(&ax->buflock);
|
|
|
|
set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
|
|
actual = ax->tty->ops->write(ax->tty, ax->xbuff, count);
|
|
dev->stats.tx_packets++;
|
|
dev->stats.tx_bytes += actual;
|
|
|
|
netif_trans_update(ax->dev);
|
|
ax->xleft = count - actual;
|
|
ax->xhead = ax->xbuff + actual;
|
|
}
|
|
|
|
/* Encapsulate an AX.25 packet and kick it into a TTY queue. */
|
|
static netdev_tx_t ax_xmit(struct sk_buff *skb, struct net_device *dev)
|
|
{
|
|
struct mkiss *ax = netdev_priv(dev);
|
|
|
|
if (skb->protocol == htons(ETH_P_IP))
|
|
return ax25_ip_xmit(skb);
|
|
|
|
if (!netif_running(dev)) {
|
|
printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name);
|
|
return NETDEV_TX_BUSY;
|
|
}
|
|
|
|
if (netif_queue_stopped(dev)) {
|
|
/*
|
|
* May be we must check transmitter timeout here ?
|
|
* 14 Oct 1994 Dmitry Gorodchanin.
|
|
*/
|
|
if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) {
|
|
/* 20 sec timeout not reached */
|
|
return NETDEV_TX_BUSY;
|
|
}
|
|
|
|
printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name,
|
|
(tty_chars_in_buffer(ax->tty) || ax->xleft) ?
|
|
"bad line quality" : "driver error");
|
|
|
|
ax->xleft = 0;
|
|
clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
|
|
netif_start_queue(dev);
|
|
}
|
|
|
|
/* We were not busy, so we are now... :-) */
|
|
netif_stop_queue(dev);
|
|
ax_encaps(dev, skb->data, skb->len);
|
|
kfree_skb(skb);
|
|
|
|
return NETDEV_TX_OK;
|
|
}
|
|
|
|
static int ax_open_dev(struct net_device *dev)
|
|
{
|
|
struct mkiss *ax = netdev_priv(dev);
|
|
|
|
if (ax->tty == NULL)
|
|
return -ENODEV;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Open the low-level part of the AX25 channel. Easy! */
|
|
static int ax_open(struct net_device *dev)
|
|
{
|
|
struct mkiss *ax = netdev_priv(dev);
|
|
unsigned long len;
|
|
|
|
if (ax->tty == NULL)
|
|
return -ENODEV;
|
|
|
|
/*
|
|
* Allocate the frame buffers:
|
|
*
|
|
* rbuff Receive buffer.
|
|
* xbuff Transmit buffer.
|
|
*/
|
|
len = dev->mtu * 2;
|
|
|
|
/*
|
|
* allow for arrival of larger UDP packets, even if we say not to
|
|
* also fixes a bug in which SunOS sends 512-byte packets even with
|
|
* an MSS of 128
|
|
*/
|
|
if (len < 576 * 2)
|
|
len = 576 * 2;
|
|
|
|
if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
|
|
goto norbuff;
|
|
|
|
if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
|
|
goto noxbuff;
|
|
|
|
ax->mtu = dev->mtu + 73;
|
|
ax->buffsize = len;
|
|
ax->rcount = 0;
|
|
ax->xleft = 0;
|
|
|
|
ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */
|
|
|
|
spin_lock_init(&ax->buflock);
|
|
|
|
return 0;
|
|
|
|
noxbuff:
|
|
kfree(ax->rbuff);
|
|
|
|
norbuff:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
|
|
/* Close the low-level part of the AX25 channel. Easy! */
|
|
static int ax_close(struct net_device *dev)
|
|
{
|
|
struct mkiss *ax = netdev_priv(dev);
|
|
|
|
if (ax->tty)
|
|
clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
|
|
|
|
netif_stop_queue(dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct net_device_ops ax_netdev_ops = {
|
|
.ndo_open = ax_open_dev,
|
|
.ndo_stop = ax_close,
|
|
.ndo_start_xmit = ax_xmit,
|
|
.ndo_set_mac_address = ax_set_mac_address,
|
|
};
|
|
|
|
static void ax_setup(struct net_device *dev)
|
|
{
|
|
/* Finish setting up the DEVICE info. */
|
|
dev->mtu = AX_MTU;
|
|
dev->hard_header_len = AX25_MAX_HEADER_LEN;
|
|
dev->addr_len = AX25_ADDR_LEN;
|
|
dev->type = ARPHRD_AX25;
|
|
dev->tx_queue_len = 10;
|
|
dev->header_ops = &ax25_header_ops;
|
|
dev->netdev_ops = &ax_netdev_ops;
|
|
|
|
|
|
memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
|
|
memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
|
|
|
|
dev->flags = IFF_BROADCAST | IFF_MULTICAST;
|
|
}
|
|
|
|
/*
|
|
* We have a potential race on dereferencing tty->disc_data, because the tty
|
|
* layer provides no locking at all - thus one cpu could be running
|
|
* sixpack_receive_buf while another calls sixpack_close, which zeroes
|
|
* tty->disc_data and frees the memory that sixpack_receive_buf is using. The
|
|
* best way to fix this is to use a rwlock in the tty struct, but for now we
|
|
* use a single global rwlock for all ttys in ppp line discipline.
|
|
*/
|
|
static DEFINE_RWLOCK(disc_data_lock);
|
|
|
|
static struct mkiss *mkiss_get(struct tty_struct *tty)
|
|
{
|
|
struct mkiss *ax;
|
|
|
|
read_lock(&disc_data_lock);
|
|
ax = tty->disc_data;
|
|
if (ax)
|
|
refcount_inc(&ax->refcnt);
|
|
read_unlock(&disc_data_lock);
|
|
|
|
return ax;
|
|
}
|
|
|
|
static void mkiss_put(struct mkiss *ax)
|
|
{
|
|
if (refcount_dec_and_test(&ax->refcnt))
|
|
complete(&ax->dead);
|
|
}
|
|
|
|
static int crc_force = 0; /* Can be overridden with insmod */
|
|
|
|
static int mkiss_open(struct tty_struct *tty)
|
|
{
|
|
struct net_device *dev;
|
|
struct mkiss *ax;
|
|
int err;
|
|
|
|
if (!capable(CAP_NET_ADMIN))
|
|
return -EPERM;
|
|
if (tty->ops->write == NULL)
|
|
return -EOPNOTSUPP;
|
|
|
|
dev = alloc_netdev(sizeof(struct mkiss), "ax%d", NET_NAME_UNKNOWN,
|
|
ax_setup);
|
|
if (!dev) {
|
|
err = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
ax = netdev_priv(dev);
|
|
ax->dev = dev;
|
|
|
|
spin_lock_init(&ax->buflock);
|
|
refcount_set(&ax->refcnt, 1);
|
|
init_completion(&ax->dead);
|
|
|
|
ax->tty = tty;
|
|
tty->disc_data = ax;
|
|
tty->receive_room = 65535;
|
|
|
|
tty_driver_flush_buffer(tty);
|
|
|
|
/* Restore default settings */
|
|
dev->type = ARPHRD_AX25;
|
|
|
|
/* Perform the low-level AX25 initialization. */
|
|
err = ax_open(ax->dev);
|
|
if (err)
|
|
goto out_free_netdev;
|
|
|
|
err = register_netdev(dev);
|
|
if (err)
|
|
goto out_free_buffers;
|
|
|
|
/* after register_netdev() - because else printk smashes the kernel */
|
|
switch (crc_force) {
|
|
case 3:
|
|
ax->crcmode = CRC_MODE_SMACK;
|
|
printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n",
|
|
ax->dev->name);
|
|
break;
|
|
case 2:
|
|
ax->crcmode = CRC_MODE_FLEX;
|
|
printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n",
|
|
ax->dev->name);
|
|
break;
|
|
case 1:
|
|
ax->crcmode = CRC_MODE_NONE;
|
|
printk(KERN_INFO "mkiss: %s: crc mode disabled.\n",
|
|
ax->dev->name);
|
|
break;
|
|
case 0:
|
|
/* fall through */
|
|
default:
|
|
crc_force = 0;
|
|
printk(KERN_INFO "mkiss: %s: crc mode is auto.\n",
|
|
ax->dev->name);
|
|
ax->crcmode = CRC_MODE_SMACK_TEST;
|
|
}
|
|
ax->crcauto = (crc_force ? 0 : 1);
|
|
|
|
netif_start_queue(dev);
|
|
|
|
/* Done. We have linked the TTY line to a channel. */
|
|
return 0;
|
|
|
|
out_free_buffers:
|
|
kfree(ax->rbuff);
|
|
kfree(ax->xbuff);
|
|
|
|
out_free_netdev:
|
|
free_netdev(dev);
|
|
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static void mkiss_close(struct tty_struct *tty)
|
|
{
|
|
struct mkiss *ax;
|
|
|
|
write_lock_irq(&disc_data_lock);
|
|
ax = tty->disc_data;
|
|
tty->disc_data = NULL;
|
|
write_unlock_irq(&disc_data_lock);
|
|
|
|
if (!ax)
|
|
return;
|
|
|
|
/*
|
|
* We have now ensured that nobody can start using ap from now on, but
|
|
* we have to wait for all existing users to finish.
|
|
*/
|
|
if (!refcount_dec_and_test(&ax->refcnt))
|
|
wait_for_completion(&ax->dead);
|
|
/*
|
|
* Halt the transmit queue so that a new transmit cannot scribble
|
|
* on our buffers
|
|
*/
|
|
netif_stop_queue(ax->dev);
|
|
|
|
/* Free all AX25 frame buffers. */
|
|
kfree(ax->rbuff);
|
|
kfree(ax->xbuff);
|
|
|
|
ax->tty = NULL;
|
|
|
|
unregister_netdev(ax->dev);
|
|
}
|
|
|
|
/* Perform I/O control on an active ax25 channel. */
|
|
static int mkiss_ioctl(struct tty_struct *tty, struct file *file,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct mkiss *ax = mkiss_get(tty);
|
|
struct net_device *dev;
|
|
unsigned int tmp, err;
|
|
|
|
/* First make sure we're connected. */
|
|
if (ax == NULL)
|
|
return -ENXIO;
|
|
dev = ax->dev;
|
|
|
|
switch (cmd) {
|
|
case SIOCGIFNAME:
|
|
err = copy_to_user((void __user *) arg, ax->dev->name,
|
|
strlen(ax->dev->name) + 1) ? -EFAULT : 0;
|
|
break;
|
|
|
|
case SIOCGIFENCAP:
|
|
err = put_user(4, (int __user *) arg);
|
|
break;
|
|
|
|
case SIOCSIFENCAP:
|
|
if (get_user(tmp, (int __user *) arg)) {
|
|
err = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
ax->mode = tmp;
|
|
dev->addr_len = AX25_ADDR_LEN;
|
|
dev->hard_header_len = AX25_KISS_HEADER_LEN +
|
|
AX25_MAX_HEADER_LEN + 3;
|
|
dev->type = ARPHRD_AX25;
|
|
|
|
err = 0;
|
|
break;
|
|
|
|
case SIOCSIFHWADDR: {
|
|
char addr[AX25_ADDR_LEN];
|
|
|
|
if (copy_from_user(&addr,
|
|
(void __user *) arg, AX25_ADDR_LEN)) {
|
|
err = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
netif_tx_lock_bh(dev);
|
|
memcpy(dev->dev_addr, addr, AX25_ADDR_LEN);
|
|
netif_tx_unlock_bh(dev);
|
|
|
|
err = 0;
|
|
break;
|
|
}
|
|
default:
|
|
err = -ENOIOCTLCMD;
|
|
}
|
|
|
|
mkiss_put(ax);
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Handle the 'receiver data ready' interrupt.
|
|
* This function is called by the 'tty_io' module in the kernel when
|
|
* a block of data has been received, which can now be decapsulated
|
|
* and sent on to the AX.25 layer for further processing.
|
|
*/
|
|
static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,
|
|
char *fp, int count)
|
|
{
|
|
struct mkiss *ax = mkiss_get(tty);
|
|
|
|
if (!ax)
|
|
return;
|
|
|
|
/*
|
|
* Argh! mtu change time! - costs us the packet part received
|
|
* at the change
|
|
*/
|
|
if (ax->mtu != ax->dev->mtu + 73)
|
|
ax_changedmtu(ax);
|
|
|
|
/* Read the characters out of the buffer */
|
|
while (count--) {
|
|
if (fp != NULL && *fp++) {
|
|
if (!test_and_set_bit(AXF_ERROR, &ax->flags))
|
|
ax->dev->stats.rx_errors++;
|
|
cp++;
|
|
continue;
|
|
}
|
|
|
|
kiss_unesc(ax, *cp++);
|
|
}
|
|
|
|
mkiss_put(ax);
|
|
tty_unthrottle(tty);
|
|
}
|
|
|
|
/*
|
|
* Called by the driver when there's room for more data. If we have
|
|
* more packets to send, we send them here.
|
|
*/
|
|
static void mkiss_write_wakeup(struct tty_struct *tty)
|
|
{
|
|
struct mkiss *ax = mkiss_get(tty);
|
|
int actual;
|
|
|
|
if (!ax)
|
|
return;
|
|
|
|
if (ax->xleft <= 0) {
|
|
/* Now serial buffer is almost free & we can start
|
|
* transmission of another packet
|
|
*/
|
|
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
|
|
|
|
netif_wake_queue(ax->dev);
|
|
goto out;
|
|
}
|
|
|
|
actual = tty->ops->write(tty, ax->xhead, ax->xleft);
|
|
ax->xleft -= actual;
|
|
ax->xhead += actual;
|
|
|
|
out:
|
|
mkiss_put(ax);
|
|
}
|
|
|
|
static struct tty_ldisc_ops ax_ldisc = {
|
|
.owner = THIS_MODULE,
|
|
.magic = TTY_LDISC_MAGIC,
|
|
.name = "mkiss",
|
|
.open = mkiss_open,
|
|
.close = mkiss_close,
|
|
.ioctl = mkiss_ioctl,
|
|
.receive_buf = mkiss_receive_buf,
|
|
.write_wakeup = mkiss_write_wakeup
|
|
};
|
|
|
|
static const char banner[] __initconst = KERN_INFO \
|
|
"mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n";
|
|
static const char msg_regfail[] __initconst = KERN_ERR \
|
|
"mkiss: can't register line discipline (err = %d)\n";
|
|
|
|
static int __init mkiss_init_driver(void)
|
|
{
|
|
int status;
|
|
|
|
printk(banner);
|
|
|
|
status = tty_register_ldisc(N_AX25, &ax_ldisc);
|
|
if (status != 0)
|
|
printk(msg_regfail, status);
|
|
|
|
return status;
|
|
}
|
|
|
|
static const char msg_unregfail[] = KERN_ERR \
|
|
"mkiss: can't unregister line discipline (err = %d)\n";
|
|
|
|
static void __exit mkiss_exit_driver(void)
|
|
{
|
|
int ret;
|
|
|
|
if ((ret = tty_unregister_ldisc(N_AX25)))
|
|
printk(msg_unregfail, ret);
|
|
}
|
|
|
|
MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>");
|
|
MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs");
|
|
module_param(crc_force, int, 0);
|
|
MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_LDISC(N_AX25);
|
|
|
|
module_init(mkiss_init_driver);
|
|
module_exit(mkiss_exit_driver);
|