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Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards

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orangepi/linux-orangepi-5.10.y.git/trunk/drivers/net/hamradio/mkiss.c
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// 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
 
/* some arch define END as assembly function ending, just undef it */
#undef	END
/* 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);
<------><------><------>fallthrough;
<------><------>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);
<------><------><------>fallthrough;
<------><------>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:
<------>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);
 
<------>unregister_netdev(ax->dev);
 
<------>/* Free all AX25 frame buffers after unreg. */
<------>kfree(ax->rbuff);
<------>kfree(ax->xbuff);
 
<------>ax->tty = NULL;
 
<------>free_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);
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