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linux/drivers/net/hamradio/mkiss.c

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/*
* This program is free software; you can distribute it and/or modify it
* under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
*
* 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/config.h>
#include <linux/module.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <asm/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/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 <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 */
struct net_device_stats stats;
/* 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
atomic_t refcnt;
struct semaphore dead_sem;
};
/*---------------------------------------------------------------------------*/
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 if (len > 0)
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->stats.rx_errors++;
spin_unlock_bh(&ax->buflock);
return;
}
if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) {
printk(KERN_INFO
"mkiss: %s: Switchting 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->stats.rx_errors++;
spin_unlock_bh(&ax->buflock);
return;
}
if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) {
printk(KERN_INFO
"mkiss: %s: Switchting 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;
}
}
spin_unlock_bh(&ax->buflock);
count = ax->rcount;
if ((skb = dev_alloc_skb(count)) == NULL) {
printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n",
ax->dev->name);
ax->stats.rx_dropped++;
return;
}
spin_lock_bh(&ax->buflock);
memcpy(skb_put(skb,count), ax->rbuff, count);
spin_unlock_bh(&ax->buflock);
skb->protocol = ax25_type_trans(skb, ax->dev);
netif_rx(skb);
ax->dev->last_rx = jiffies;
ax->stats.rx_packets++;
ax->stats.rx_bytes += count;
}
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->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;
spin_lock_irq(&dev->xmit_lock);
memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
spin_unlock_irq(&dev->xmit_lock);
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;
ax->stats.tx_dropped++;
}
}
ax->xhead = ax->xbuff;
if (ax->rcount) {
if (ax->rcount <= len) {
memcpy(ax->rbuff, orbuff, ax->rcount);
} else {
ax->rcount = 0;
ax->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 ... */
len = ax->mtu;
printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name);
ax->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 %s %d\n", ax->dev->name, (len) ? "set to" : "is", cmd);
}
spin_unlock_bh(&ax->buflock);
netif_start_queue(dev);
return;
default:
count = kiss_esc(p, (unsigned char *)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, (unsigned char *)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, (unsigned char *)ax->xbuff, crc, len+2);
break;
default:
count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
}
}
set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
actual = ax->tty->driver->write(ax->tty, ax->xbuff, count);
ax->stats.tx_packets++;
ax->stats.tx_bytes += actual;
ax->dev->trans_start = jiffies;
ax->xleft = count - actual;
ax->xhead = ax->xbuff + actual;
}
/* Encapsulate an AX.25 packet and kick it into a TTY queue. */
static int ax_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct mkiss *ax = netdev_priv(dev);
if (!netif_running(dev)) {
printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name);
return 1;
}
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 + 20 * HZ)) {
/* 20 sec timeout not reached */
return 1;
}
printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name,
(ax->tty->driver->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... :-) */
if (skb != NULL) {
netif_stop_queue(dev);
ax_encaps(dev, skb->data, skb->len);
kfree_skb(skb);
}
return 0;
}
static int ax_open_dev(struct net_device *dev)
{
struct mkiss *ax = netdev_priv(dev);
if (ax->tty == NULL)
return -ENODEV;
return 0;
}
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
/* Return the frame type ID */
static int ax_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
void *daddr, void *saddr, unsigned len)
{
#ifdef CONFIG_INET
if (type != htons(ETH_P_AX25))
return ax25_hard_header(skb, dev, type, daddr, saddr, len);
#endif
return 0;
}
static int ax_rebuild_header(struct sk_buff *skb)
{
#ifdef CONFIG_INET
return ax25_rebuild_header(skb);
#else
return 0;
#endif
}
#endif /* CONFIG_{AX25,AX25_MODULE} */
/* 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 struct net_device_stats *ax_get_stats(struct net_device *dev)
{
struct mkiss *ax = netdev_priv(dev);
return &ax->stats;
}
static void ax_setup(struct net_device *dev)
{
static char ax25_bcast[AX25_ADDR_LEN] =
{'Q'<<1,'S'<<1,'T'<<1,' '<<1,' '<<1,' '<<1,'0'<<1};
static char ax25_test[AX25_ADDR_LEN] =
{'L'<<1,'I'<<1,'N'<<1,'U'<<1,'X'<<1,' '<<1,'1'<<1};
/* Finish setting up the DEVICE info. */
dev->mtu = AX_MTU;
dev->hard_start_xmit = ax_xmit;
dev->open = ax_open_dev;
dev->stop = ax_close;
dev->get_stats = ax_get_stats;
dev->set_mac_address = ax_set_mac_address;
dev->hard_header_len = 0;
dev->addr_len = 0;
dev->type = ARPHRD_AX25;
dev->tx_queue_len = 10;
dev->hard_header = ax_header;
dev->rebuild_header = ax_rebuild_header;
memcpy(dev->broadcast, ax25_bcast, AX25_ADDR_LEN);
memcpy(dev->dev_addr, ax25_test, 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)
atomic_inc(&ax->refcnt);
read_unlock(&disc_data_lock);
return ax;
}
static void mkiss_put(struct mkiss *ax)
{
if (atomic_dec_and_test(&ax->refcnt))
up(&ax->dead_sem);
}
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;
dev = alloc_netdev(sizeof(struct mkiss), "ax%d", ax_setup);
if (!dev) {
err = -ENOMEM;
goto out;
}
ax = netdev_priv(dev);
ax->dev = dev;
spin_lock_init(&ax->buflock);
atomic_set(&ax->refcnt, 1);
init_MUTEX_LOCKED(&ax->dead_sem);
ax->tty = tty;
tty->disc_data = ax;
if (tty->driver->flush_buffer)
tty->driver->flush_buffer(tty);
/* Restore default settings */
dev->type = ARPHRD_AX25;
/* Perform the low-level AX25 initialization. */
if ((err = ax_open(ax->dev))) {
goto out_free_netdev;
}
if (register_netdev(dev))
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(&disc_data_lock);
ax = tty->disc_data;
tty->disc_data = NULL;
write_unlock(&disc_data_lock);
if (ax == 0)
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 (!atomic_dec_and_test(&ax->refcnt))
down(&ax->dead_sem);
unregister_netdev(ax->dev);
/* Free all AX25 frame buffers. */
kfree(ax->rbuff);
kfree(ax->xbuff);
ax->tty = NULL;
}
/* 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 = ax->dev;
unsigned int tmp, err;
/* First make sure we're connected. */
if (ax == NULL)
return -ENXIO;
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;
}
spin_lock_irq(&dev->xmit_lock);
memcpy(dev->dev_addr, addr, AX25_ADDR_LEN);
spin_unlock_irq(&dev->xmit_lock);
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->stats.rx_errors++;
cp++;
continue;
}
kiss_unesc(ax, *cp++);
}
mkiss_put(ax);
if (test_and_clear_bit(TTY_THROTTLED, &tty->flags)
&& tty->driver->unthrottle)
tty->driver->unthrottle(tty);
}
static int mkiss_receive_room(struct tty_struct *tty)
{
return 65536; /* We can handle an infinite amount of data. :-) */
}
/*
* 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->driver->write(tty, ax->xhead, ax->xleft);
ax->xleft -= actual;
ax->xhead += actual;
out:
mkiss_put(ax);
}
static struct tty_ldisc 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,
.receive_room = mkiss_receive_room,
.write_wakeup = mkiss_write_wakeup
};
static char banner[] __initdata = KERN_INFO \
"mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n";
static char msg_regfail[] __initdata = KERN_ERR \
"mkiss: can't register line discipline (err = %d)\n";
static int __init mkiss_init_driver(void)
{
int status;
printk(banner);
if ((status = tty_register_ldisc(N_AX25, &ax_ldisc)) != 0)
printk(msg_regfail);
return status;
}
static const char msg_unregfail[] __exitdata = 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_PARM(crc_force, "i");
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);
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