2 * This program is free software; you can distribute it and/or modify it
3 * under the terms of the GNU General Public License (Version 2) as
4 * published by the Free Software Foundation.
6 * This program is distributed in the hope it will be useful, but WITHOUT
7 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
8 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * You should have received a copy of the GNU General Public License along
12 * with this program; if not, write to the Free Software Foundation, Inc.,
13 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
15 * Copyright (C) Hans Alblas PE1AYX <hans@esrac.ele.tue.nl>
16 * Copyright (C) 2004, 05 Ralf Baechle DL5RB <ralf@linux-mips.org>
17 * Copyright (C) 2004, 05 Thomas Osterried DL9SAU <thomas@x-berg.in-berlin.de>
19 #include <linux/module.h>
20 #include <asm/system.h>
21 #include <linux/bitops.h>
22 #include <asm/uaccess.h>
23 #include <linux/crc16.h>
24 #include <linux/string.h>
26 #include <linux/interrupt.h>
28 #include <linux/inet.h>
29 #include <linux/tty.h>
30 #include <linux/errno.h>
31 #include <linux/netdevice.h>
32 #include <linux/major.h>
33 #include <linux/init.h>
34 #include <linux/rtnetlink.h>
35 #include <linux/etherdevice.h>
36 #include <linux/skbuff.h>
37 #include <linux/if_arp.h>
38 #include <linux/jiffies.h>
44 /* SLIP/KISS protocol characters. */
45 #define END 0300 /* indicates end of frame */
46 #define ESC 0333 /* indicates byte stuffing */
47 #define ESC_END 0334 /* ESC ESC_END means END 'data' */
48 #define ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */
51 struct tty_struct *tty; /* ptr to TTY structure */
52 struct net_device *dev; /* easy for intr handling */
54 /* These are pointers to the malloc()ed frame buffers. */
55 spinlock_t buflock;/* lock for rbuf and xbuf */
56 unsigned char *rbuff; /* receiver buffer */
57 int rcount; /* received chars counter */
58 unsigned char *xbuff; /* transmitter buffer */
59 unsigned char *xhead; /* pointer to next byte to XMIT */
60 int xleft; /* bytes left in XMIT queue */
62 /* Detailed SLIP statistics. */
63 int mtu; /* Our mtu (to spot changes!) */
64 int buffsize; /* Max buffers sizes */
66 unsigned long flags; /* Flag values/ mode etc */
67 /* long req'd: used by set_bit --RR */
68 #define AXF_INUSE 0 /* Channel in use */
69 #define AXF_ESCAPE 1 /* ESC received */
70 #define AXF_ERROR 2 /* Parity, etc. error */
71 #define AXF_KEEPTEST 3 /* Keepalive test flag */
72 #define AXF_OUTWAIT 4 /* is outpacket was flag */
75 int crcmode; /* MW: for FlexNet, SMACK etc. */
76 int crcauto; /* CRC auto mode */
78 #define CRC_MODE_NONE 0
79 #define CRC_MODE_FLEX 1
80 #define CRC_MODE_SMACK 2
81 #define CRC_MODE_FLEX_TEST 3
82 #define CRC_MODE_SMACK_TEST 4
85 struct semaphore dead_sem;
88 /*---------------------------------------------------------------------------*/
90 static const unsigned short crc_flex_table[] = {
91 0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38,
92 0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770,
93 0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9,
94 0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1,
95 0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a,
96 0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672,
97 0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb,
98 0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3,
99 0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c,
100 0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574,
101 0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd,
102 0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5,
103 0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e,
104 0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476,
105 0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf,
106 0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7,
107 0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30,
108 0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378,
109 0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1,
110 0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9,
111 0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32,
112 0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a,
113 0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3,
114 0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb,
115 0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34,
116 0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c,
117 0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5,
118 0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd,
119 0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36,
120 0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e,
121 0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7,
122 0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff
125 static unsigned short calc_crc_flex(unsigned char *cp, int size)
127 unsigned short crc = 0xffff;
130 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
135 static int check_crc_flex(unsigned char *cp, int size)
137 unsigned short crc = 0xffff;
143 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
145 if ((crc & 0xffff) != 0x7070)
151 static int check_crc_16(unsigned char *cp, int size)
153 unsigned short crc = 0x0000;
158 crc = crc16(0, cp, size);
167 * Standard encapsulation
170 static int kiss_esc(unsigned char *s, unsigned char *d, int len)
172 unsigned char *ptr = d;
176 * Send an initial END character to flush out any data that may have
177 * accumulated in the receiver due to line noise.
205 * OK its ugly, but tell me a better solution without copying the
206 * packet to a temporary buffer :-)
208 static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc,
211 unsigned char *ptr = d;
244 /* Send one completely decapsulated AX.25 packet to the AX.25 layer. */
245 static void ax_bump(struct mkiss *ax)
251 spin_lock_irqsave(&ax->buflock, flags);
252 if (ax->rbuff[0] > 0x0f) {
253 if (ax->rbuff[0] & 0x80) {
254 if (check_crc_16(ax->rbuff, ax->rcount) < 0) {
255 ax->dev->stats.rx_errors++;
256 spin_unlock_irqrestore(&ax->buflock, flags);
260 if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) {
262 "mkiss: %s: Switchting to crc-smack\n",
264 ax->crcmode = CRC_MODE_SMACK;
268 } else if (ax->rbuff[0] & 0x20) {
269 if (check_crc_flex(ax->rbuff, ax->rcount) < 0) {
270 ax->dev->stats.rx_errors++;
271 spin_unlock_irqrestore(&ax->buflock, flags);
274 if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) {
276 "mkiss: %s: Switchting to crc-flexnet\n",
278 ax->crcmode = CRC_MODE_FLEX;
283 * dl9sau bugfix: the trailling two bytes flexnet crc
284 * will not be passed to the kernel. thus we have to
285 * correct the kissparm signature, because it indicates
286 * a crc but there's none
294 if ((skb = dev_alloc_skb(count)) == NULL) {
295 printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n",
297 ax->dev->stats.rx_dropped++;
298 spin_unlock_irqrestore(&ax->buflock, flags);
302 memcpy(skb_put(skb,count), ax->rbuff, count);
303 skb->protocol = ax25_type_trans(skb, ax->dev);
305 ax->dev->stats.rx_packets++;
306 ax->dev->stats.rx_bytes += count;
307 spin_unlock_irqrestore(&ax->buflock, flags);
310 static void kiss_unesc(struct mkiss *ax, unsigned char s)
316 /* drop keeptest bit = VSV */
317 if (test_bit(AXF_KEEPTEST, &ax->flags))
318 clear_bit(AXF_KEEPTEST, &ax->flags);
320 if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2))
323 clear_bit(AXF_ESCAPE, &ax->flags);
328 set_bit(AXF_ESCAPE, &ax->flags);
331 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
335 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
340 spin_lock_irqsave(&ax->buflock, flags);
341 if (!test_bit(AXF_ERROR, &ax->flags)) {
342 if (ax->rcount < ax->buffsize) {
343 ax->rbuff[ax->rcount++] = s;
344 spin_unlock_irqrestore(&ax->buflock, flags);
348 ax->dev->stats.rx_over_errors++;
349 set_bit(AXF_ERROR, &ax->flags);
351 spin_unlock_irqrestore(&ax->buflock, flags);
354 static int ax_set_mac_address(struct net_device *dev, void *addr)
356 struct sockaddr_ax25 *sa = addr;
358 netif_tx_lock_bh(dev);
359 netif_addr_lock(dev);
360 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
361 netif_addr_unlock(dev);
362 netif_tx_unlock_bh(dev);
367 /*---------------------------------------------------------------------------*/
369 static void ax_changedmtu(struct mkiss *ax)
371 struct net_device *dev = ax->dev;
372 unsigned char *xbuff, *rbuff, *oxbuff, *orbuff;
379 * allow for arrival of larger UDP packets, even if we say not to
380 * also fixes a bug in which SunOS sends 512-byte packets even with
386 xbuff = kmalloc(len + 4, GFP_ATOMIC);
387 rbuff = kmalloc(len + 4, GFP_ATOMIC);
389 if (xbuff == NULL || rbuff == NULL) {
390 printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, "
391 "MTU change cancelled.\n",
399 spin_lock_irqsave(&ax->buflock, flags);
407 if (ax->xleft <= len) {
408 memcpy(ax->xbuff, ax->xhead, ax->xleft);
411 dev->stats.tx_dropped++;
415 ax->xhead = ax->xbuff;
418 if (ax->rcount <= len) {
419 memcpy(ax->rbuff, orbuff, ax->rcount);
422 dev->stats.rx_over_errors++;
423 set_bit(AXF_ERROR, &ax->flags);
427 ax->mtu = dev->mtu + 73;
430 spin_unlock_irqrestore(&ax->buflock, flags);
436 /* Encapsulate one AX.25 packet and stuff into a TTY queue. */
437 static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
439 struct mkiss *ax = netdev_priv(dev);
444 if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */
447 if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */
449 printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name);
450 dev->stats.tx_dropped++;
451 netif_start_queue(dev);
457 spin_lock_irqsave(&ax->buflock, flags);
458 if ((*p & 0x0f) != 0) {
459 /* Configuration Command (kissparms(1).
460 * Protocol spec says: never append CRC.
461 * This fixes a very old bug in the linux
462 * kiss driver. -- dl9sau */
465 /* command from userspace especially for us,
466 * not for delivery to the tnc */
468 int cmd = (p[1] & 0xff);
471 ax->crcmode = CRC_MODE_SMACK;
474 ax->crcmode = CRC_MODE_FLEX;
477 ax->crcmode = CRC_MODE_NONE;
481 ax->crcmode = CRC_MODE_SMACK_TEST;
484 ax->crcauto = (cmd ? 0 : 1);
485 printk(KERN_INFO "mkiss: %s: crc mode %s %d\n", ax->dev->name, (len) ? "set to" : "is", cmd);
487 spin_unlock_irqrestore(&ax->buflock, flags);
488 netif_start_queue(dev);
492 count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
496 switch (ax->crcmode) {
497 case CRC_MODE_SMACK_TEST:
498 ax->crcmode = CRC_MODE_FLEX_TEST;
499 printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name);
503 crc = swab16(crc16(0, p, len));
504 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2);
506 case CRC_MODE_FLEX_TEST:
507 ax->crcmode = CRC_MODE_NONE;
508 printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name);
512 crc = calc_crc_flex(p, len);
513 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2);
517 count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
520 spin_unlock_irqrestore(&ax->buflock, flags);
522 set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
523 actual = ax->tty->ops->write(ax->tty, ax->xbuff, count);
524 dev->stats.tx_packets++;
525 dev->stats.tx_bytes += actual;
527 ax->dev->trans_start = jiffies;
528 ax->xleft = count - actual;
529 ax->xhead = ax->xbuff + actual;
532 /* Encapsulate an AX.25 packet and kick it into a TTY queue. */
533 static int ax_xmit(struct sk_buff *skb, struct net_device *dev)
535 struct mkiss *ax = netdev_priv(dev);
537 if (!netif_running(dev)) {
538 printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name);
539 return NETDEV_TX_BUSY;
542 if (netif_queue_stopped(dev)) {
544 * May be we must check transmitter timeout here ?
545 * 14 Oct 1994 Dmitry Gorodchanin.
547 if (time_before(jiffies, dev->trans_start + 20 * HZ)) {
548 /* 20 sec timeout not reached */
549 return NETDEV_TX_BUSY;
552 printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name,
553 (tty_chars_in_buffer(ax->tty) || ax->xleft) ?
554 "bad line quality" : "driver error");
557 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
558 netif_start_queue(dev);
561 /* We were not busy, so we are now... :-) */
563 netif_stop_queue(dev);
564 ax_encaps(dev, skb->data, skb->len);
571 static int ax_open_dev(struct net_device *dev)
573 struct mkiss *ax = netdev_priv(dev);
581 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
583 /* Return the frame type ID */
584 static int ax_header(struct sk_buff *skb, struct net_device *dev,
585 unsigned short type, const void *daddr,
586 const void *saddr, unsigned len)
589 if (type != ETH_P_AX25)
590 return ax25_hard_header(skb, dev, type, daddr, saddr, len);
596 static int ax_rebuild_header(struct sk_buff *skb)
599 return ax25_rebuild_header(skb);
605 #endif /* CONFIG_{AX25,AX25_MODULE} */
607 /* Open the low-level part of the AX25 channel. Easy! */
608 static int ax_open(struct net_device *dev)
610 struct mkiss *ax = netdev_priv(dev);
617 * Allocate the frame buffers:
619 * rbuff Receive buffer.
620 * xbuff Transmit buffer.
625 * allow for arrival of larger UDP packets, even if we say not to
626 * also fixes a bug in which SunOS sends 512-byte packets even with
632 if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
635 if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
638 ax->mtu = dev->mtu + 73;
643 ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */
645 spin_lock_init(&ax->buflock);
657 /* Close the low-level part of the AX25 channel. Easy! */
658 static int ax_close(struct net_device *dev)
660 struct mkiss *ax = netdev_priv(dev);
663 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
665 netif_stop_queue(dev);
670 static const struct header_ops ax_header_ops = {
672 .rebuild = ax_rebuild_header,
675 static const struct net_device_ops ax_netdev_ops = {
676 .ndo_open = ax_open_dev,
677 .ndo_stop = ax_close,
678 .ndo_start_xmit = ax_xmit,
679 .ndo_set_mac_address = ax_set_mac_address,
682 static void ax_setup(struct net_device *dev)
684 /* Finish setting up the DEVICE info. */
686 dev->hard_header_len = 0;
688 dev->type = ARPHRD_AX25;
689 dev->tx_queue_len = 10;
690 dev->header_ops = &ax_header_ops;
691 dev->netdev_ops = &ax_netdev_ops;
694 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
695 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
697 dev->flags = IFF_BROADCAST | IFF_MULTICAST;
701 * We have a potential race on dereferencing tty->disc_data, because the tty
702 * layer provides no locking at all - thus one cpu could be running
703 * sixpack_receive_buf while another calls sixpack_close, which zeroes
704 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
705 * best way to fix this is to use a rwlock in the tty struct, but for now we
706 * use a single global rwlock for all ttys in ppp line discipline.
708 static DEFINE_RWLOCK(disc_data_lock);
710 static struct mkiss *mkiss_get(struct tty_struct *tty)
715 read_lock_irqsave(&disc_data_lock, flags);
718 atomic_inc(&ax->refcnt);
719 read_unlock_irqrestore(&disc_data_lock, flags);
724 static void mkiss_put(struct mkiss *ax)
726 if (atomic_dec_and_test(&ax->refcnt))
730 static int crc_force = 0; /* Can be overridden with insmod */
732 static int mkiss_open(struct tty_struct *tty)
734 struct net_device *dev;
738 if (!capable(CAP_NET_ADMIN))
740 if (tty->ops->write == NULL)
743 dev = alloc_netdev(sizeof(struct mkiss), "ax%d", ax_setup);
749 ax = netdev_priv(dev);
752 spin_lock_init(&ax->buflock);
753 atomic_set(&ax->refcnt, 1);
754 init_MUTEX_LOCKED(&ax->dead_sem);
758 tty->receive_room = 65535;
760 tty_driver_flush_buffer(tty);
762 /* Restore default settings */
763 dev->type = ARPHRD_AX25;
765 /* Perform the low-level AX25 initialization. */
766 if ((err = ax_open(ax->dev))) {
767 goto out_free_netdev;
770 if (register_netdev(dev))
771 goto out_free_buffers;
773 /* after register_netdev() - because else printk smashes the kernel */
776 ax->crcmode = CRC_MODE_SMACK;
777 printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n",
781 ax->crcmode = CRC_MODE_FLEX;
782 printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n",
786 ax->crcmode = CRC_MODE_NONE;
787 printk(KERN_INFO "mkiss: %s: crc mode disabled.\n",
794 printk(KERN_INFO "mkiss: %s: crc mode is auto.\n",
796 ax->crcmode = CRC_MODE_SMACK_TEST;
798 ax->crcauto = (crc_force ? 0 : 1);
800 netif_start_queue(dev);
802 /* Done. We have linked the TTY line to a channel. */
816 static void mkiss_close(struct tty_struct *tty)
821 write_lock_irqsave(&disc_data_lock, flags);
823 tty->disc_data = NULL;
824 write_unlock_irqrestore(&disc_data_lock, flags);
830 * We have now ensured that nobody can start using ap from now on, but
831 * we have to wait for all existing users to finish.
833 if (!atomic_dec_and_test(&ax->refcnt))
836 unregister_netdev(ax->dev);
838 /* Free all AX25 frame buffers. */
845 /* Perform I/O control on an active ax25 channel. */
846 static int mkiss_ioctl(struct tty_struct *tty, struct file *file,
847 unsigned int cmd, unsigned long arg)
849 struct mkiss *ax = mkiss_get(tty);
850 struct net_device *dev;
851 unsigned int tmp, err;
853 /* First make sure we're connected. */
860 err = copy_to_user((void __user *) arg, ax->dev->name,
861 strlen(ax->dev->name) + 1) ? -EFAULT : 0;
865 err = put_user(4, (int __user *) arg);
869 if (get_user(tmp, (int __user *) arg)) {
875 dev->addr_len = AX25_ADDR_LEN;
876 dev->hard_header_len = AX25_KISS_HEADER_LEN +
877 AX25_MAX_HEADER_LEN + 3;
878 dev->type = ARPHRD_AX25;
883 case SIOCSIFHWADDR: {
884 char addr[AX25_ADDR_LEN];
886 if (copy_from_user(&addr,
887 (void __user *) arg, AX25_ADDR_LEN)) {
892 netif_tx_lock_bh(dev);
893 memcpy(dev->dev_addr, addr, AX25_ADDR_LEN);
894 netif_tx_unlock_bh(dev);
909 * Handle the 'receiver data ready' interrupt.
910 * This function is called by the 'tty_io' module in the kernel when
911 * a block of data has been received, which can now be decapsulated
912 * and sent on to the AX.25 layer for further processing.
914 static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,
917 struct mkiss *ax = mkiss_get(tty);
923 * Argh! mtu change time! - costs us the packet part received
926 if (ax->mtu != ax->dev->mtu + 73)
929 /* Read the characters out of the buffer */
931 if (fp != NULL && *fp++) {
932 if (!test_and_set_bit(AXF_ERROR, &ax->flags))
933 ax->dev->stats.rx_errors++;
938 kiss_unesc(ax, *cp++);
946 * Called by the driver when there's room for more data. If we have
947 * more packets to send, we send them here.
949 static void mkiss_write_wakeup(struct tty_struct *tty)
951 struct mkiss *ax = mkiss_get(tty);
957 if (ax->xleft <= 0) {
958 /* Now serial buffer is almost free & we can start
959 * transmission of another packet
961 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
963 netif_wake_queue(ax->dev);
967 actual = tty->ops->write(tty, ax->xhead, ax->xleft);
975 static struct tty_ldisc_ops ax_ldisc = {
976 .owner = THIS_MODULE,
977 .magic = TTY_LDISC_MAGIC,
980 .close = mkiss_close,
981 .ioctl = mkiss_ioctl,
982 .receive_buf = mkiss_receive_buf,
983 .write_wakeup = mkiss_write_wakeup
986 static const char banner[] __initdata = KERN_INFO \
987 "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n";
988 static const char msg_regfail[] __initdata = KERN_ERR \
989 "mkiss: can't register line discipline (err = %d)\n";
991 static int __init mkiss_init_driver(void)
997 status = tty_register_ldisc(N_AX25, &ax_ldisc);
999 printk(msg_regfail, status);
1004 static const char msg_unregfail[] __exitdata = KERN_ERR \
1005 "mkiss: can't unregister line discipline (err = %d)\n";
1007 static void __exit mkiss_exit_driver(void)
1011 if ((ret = tty_unregister_ldisc(N_AX25)))
1012 printk(msg_unregfail, ret);
1015 MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>");
1016 MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs");
1017 module_param(crc_force, int, 0);
1018 MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]");
1019 MODULE_LICENSE("GPL");
1020 MODULE_ALIAS_LDISC(N_AX25);
1022 module_init(mkiss_init_driver);
1023 module_exit(mkiss_exit_driver);