2 * 6pack.c This module implements the 6pack protocol for kernel-based
3 * devices like TTY. It interfaces between a raw TTY and the
4 * kernel's AX.25 protocol layers.
6 * Authors: Andreas Könsgen <ajk@comnets.uni-bremen.de>
7 * Ralf Baechle DL5RB <ralf@linux-mips.org>
9 * Quite a lot of stuff "stolen" by Joerg Reuter from slip.c, written by
11 * Laurence Culhane, <loz@holmes.demon.co.uk>
12 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
15 #include <linux/module.h>
16 #include <linux/uaccess.h>
17 #include <linux/bitops.h>
18 #include <linux/string.h>
20 #include <linux/interrupt.h>
22 #include <linux/tty.h>
23 #include <linux/errno.h>
24 #include <linux/netdevice.h>
25 #include <linux/timer.h>
26 #include <linux/slab.h>
28 #include <linux/etherdevice.h>
29 #include <linux/skbuff.h>
30 #include <linux/rtnetlink.h>
31 #include <linux/spinlock.h>
32 #include <linux/if_arp.h>
33 #include <linux/init.h>
35 #include <linux/tcp.h>
36 #include <linux/semaphore.h>
37 #include <linux/refcount.h>
39 #define SIXPACK_VERSION "Revision: 0.3.0"
41 /* sixpack priority commands */
42 #define SIXP_SEOF 0x40 /* start and end of a 6pack frame */
43 #define SIXP_TX_URUN 0x48 /* transmit overrun */
44 #define SIXP_RX_ORUN 0x50 /* receive overrun */
45 #define SIXP_RX_BUF_OVL 0x58 /* receive buffer overflow */
47 #define SIXP_CHKSUM 0xFF /* valid checksum of a 6pack frame */
49 /* masks to get certain bits out of the status bytes sent by the TNC */
51 #define SIXP_CMD_MASK 0xC0
52 #define SIXP_CHN_MASK 0x07
53 #define SIXP_PRIO_CMD_MASK 0x80
54 #define SIXP_STD_CMD_MASK 0x40
55 #define SIXP_PRIO_DATA_MASK 0x38
56 #define SIXP_TX_MASK 0x20
57 #define SIXP_RX_MASK 0x10
58 #define SIXP_RX_DCD_MASK 0x18
59 #define SIXP_LEDS_ON 0x78
60 #define SIXP_LEDS_OFF 0x60
64 #define SIXP_FOUND_TNC 0xe9
65 #define SIXP_CON_ON 0x68
66 #define SIXP_DCD_MASK 0x08
67 #define SIXP_DAMA_OFF 0
69 /* default level 2 parameters */
70 #define SIXP_TXDELAY (HZ/4) /* in 1 s */
71 #define SIXP_PERSIST 50 /* in 256ths */
72 #define SIXP_SLOTTIME (HZ/10) /* in 1 s */
73 #define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */
74 #define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */
76 /* 6pack configuration. */
77 #define SIXP_NRUNIT 31 /* MAX number of 6pack channels */
78 #define SIXP_MTU 256 /* Default MTU */
81 SIXPF_ERROR, /* Parity, etc. error */
86 struct tty_struct *tty; /* ptr to TTY structure */
87 struct net_device *dev; /* easy for intr handling */
89 /* These are pointers to the malloc()ed frame buffers. */
90 unsigned char *rbuff; /* receiver buffer */
91 int rcount; /* received chars counter */
92 unsigned char *xbuff; /* transmitter buffer */
93 unsigned char *xhead; /* next byte to XMIT */
94 int xleft; /* bytes left in XMIT queue */
96 unsigned char raw_buf[4];
97 unsigned char cooked_buf[400];
99 unsigned int rx_count;
100 unsigned int rx_count_cooked;
102 int mtu; /* Our mtu (to spot changes!) */
103 int buffsize; /* Max buffers sizes */
105 unsigned long flags; /* Flag values/ mode etc */
106 unsigned char mode; /* 6pack mode */
109 unsigned char tx_delay;
110 unsigned char persistence;
111 unsigned char slottime;
112 unsigned char duplex;
113 unsigned char led_state;
114 unsigned char status;
115 unsigned char status1;
116 unsigned char status2;
117 unsigned char tx_enable;
118 unsigned char tnc_state;
120 struct timer_list tx_t;
121 struct timer_list resync_t;
123 struct completion dead;
127 #define AX25_6PACK_HEADER_LEN 0
129 static void sixpack_decode(struct sixpack *, const unsigned char[], int);
130 static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char);
133 * Perform the persistence/slottime algorithm for CSMA access. If the
134 * persistence check was successful, write the data to the serial driver.
135 * Note that in case of DAMA operation, the data is not sent here.
138 static void sp_xmit_on_air(struct timer_list *t)
140 struct sixpack *sp = from_timer(sp, t, tx_t);
141 int actual, when = sp->slottime;
142 static unsigned char random;
144 random = random * 17 + 41;
146 if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) {
147 sp->led_state = 0x70;
148 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
150 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
153 sp->led_state = 0x60;
154 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
157 mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100);
160 /* ----> 6pack timer interrupt handler and friends. <---- */
162 /* Encapsulate one AX.25 frame and stuff into a TTY queue. */
163 static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len)
165 unsigned char *msg, *p = icp;
168 if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */
169 msg = "oversized transmit packet!";
173 if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */
174 msg = "oversized transmit packet!";
179 msg = "invalid KISS command";
183 if ((p[0] != 0) && (len > 2)) {
184 msg = "KISS control packet too long";
188 if ((p[0] == 0) && (len < 15)) {
189 msg = "bad AX.25 packet to transmit";
193 count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay);
194 set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
197 case 1: sp->tx_delay = p[1];
199 case 2: sp->persistence = p[1];
201 case 3: sp->slottime = p[1];
203 case 4: /* ignored */
205 case 5: sp->duplex = p[1];
213 * In case of fullduplex or DAMA operation, we don't take care about the
214 * state of the DCD or of any timers, as the determination of the
215 * correct time to send is the job of the AX.25 layer. We send
216 * immediately after data has arrived.
218 if (sp->duplex == 1) {
219 sp->led_state = 0x70;
220 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
222 actual = sp->tty->ops->write(sp->tty, sp->xbuff, count);
223 sp->xleft = count - actual;
224 sp->xhead = sp->xbuff + actual;
225 sp->led_state = 0x60;
226 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
229 sp->xhead = sp->xbuff;
231 sp_xmit_on_air(&sp->tx_t);
237 sp->dev->stats.tx_dropped++;
238 netif_start_queue(sp->dev);
240 printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg);
243 /* Encapsulate an IP datagram and kick it into a TTY queue. */
245 static netdev_tx_t sp_xmit(struct sk_buff *skb, struct net_device *dev)
247 struct sixpack *sp = netdev_priv(dev);
249 if (skb->protocol == htons(ETH_P_IP))
250 return ax25_ip_xmit(skb);
252 spin_lock_bh(&sp->lock);
253 /* We were not busy, so we are now... :-) */
254 netif_stop_queue(dev);
255 dev->stats.tx_bytes += skb->len;
256 sp_encaps(sp, skb->data, skb->len);
257 spin_unlock_bh(&sp->lock);
264 static int sp_open_dev(struct net_device *dev)
266 struct sixpack *sp = netdev_priv(dev);
273 /* Close the low-level part of the 6pack channel. */
274 static int sp_close(struct net_device *dev)
276 struct sixpack *sp = netdev_priv(dev);
278 spin_lock_bh(&sp->lock);
280 /* TTY discipline is running. */
281 clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
283 netif_stop_queue(dev);
284 spin_unlock_bh(&sp->lock);
289 static int sp_set_mac_address(struct net_device *dev, void *addr)
291 struct sockaddr_ax25 *sa = addr;
293 netif_tx_lock_bh(dev);
294 netif_addr_lock(dev);
295 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
296 netif_addr_unlock(dev);
297 netif_tx_unlock_bh(dev);
302 static const struct net_device_ops sp_netdev_ops = {
303 .ndo_open = sp_open_dev,
304 .ndo_stop = sp_close,
305 .ndo_start_xmit = sp_xmit,
306 .ndo_set_mac_address = sp_set_mac_address,
309 static void sp_setup(struct net_device *dev)
311 /* Finish setting up the DEVICE info. */
312 dev->netdev_ops = &sp_netdev_ops;
313 dev->needs_free_netdev = true;
315 dev->hard_header_len = AX25_MAX_HEADER_LEN;
316 dev->header_ops = &ax25_header_ops;
318 dev->addr_len = AX25_ADDR_LEN;
319 dev->type = ARPHRD_AX25;
320 dev->tx_queue_len = 10;
322 /* Only activated in AX.25 mode */
323 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
324 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
329 /* Send one completely decapsulated IP datagram to the IP layer. */
332 * This is the routine that sends the received data to the kernel AX.25.
333 * 'cmd' is the KISS command. For AX.25 data, it is zero.
336 static void sp_bump(struct sixpack *sp, char cmd)
342 count = sp->rcount + 1;
344 sp->dev->stats.rx_bytes += count;
346 if ((skb = dev_alloc_skb(count)) == NULL)
349 ptr = skb_put(skb, count);
350 *ptr++ = cmd; /* KISS command */
352 memcpy(ptr, sp->cooked_buf + 1, count);
353 skb->protocol = ax25_type_trans(skb, sp->dev);
355 sp->dev->stats.rx_packets++;
360 sp->dev->stats.rx_dropped++;
364 /* ----------------------------------------------------------------------- */
367 * We have a potential race on dereferencing tty->disc_data, because the tty
368 * layer provides no locking at all - thus one cpu could be running
369 * sixpack_receive_buf while another calls sixpack_close, which zeroes
370 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
371 * best way to fix this is to use a rwlock in the tty struct, but for now we
372 * use a single global rwlock for all ttys in ppp line discipline.
374 static DEFINE_RWLOCK(disc_data_lock);
376 static struct sixpack *sp_get(struct tty_struct *tty)
380 read_lock(&disc_data_lock);
383 refcount_inc(&sp->refcnt);
384 read_unlock(&disc_data_lock);
389 static void sp_put(struct sixpack *sp)
391 if (refcount_dec_and_test(&sp->refcnt))
396 * Called by the TTY driver when there's room for more data. If we have
397 * more packets to send, we send them here.
399 static void sixpack_write_wakeup(struct tty_struct *tty)
401 struct sixpack *sp = sp_get(tty);
406 if (sp->xleft <= 0) {
407 /* Now serial buffer is almost free & we can start
408 * transmission of another packet */
409 sp->dev->stats.tx_packets++;
410 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
412 netif_wake_queue(sp->dev);
417 actual = tty->ops->write(tty, sp->xhead, sp->xleft);
426 /* ----------------------------------------------------------------------- */
429 * Handle the 'receiver data ready' interrupt.
430 * This function is called by the tty module in the kernel when
431 * a block of 6pack data has been received, which can now be decapsulated
432 * and sent on to some IP layer for further processing.
434 static void sixpack_receive_buf(struct tty_struct *tty,
435 const unsigned char *cp, char *fp, int count)
447 /* Read the characters out of the buffer */
452 if (!test_and_set_bit(SIXPF_ERROR, &sp->flags))
453 sp->dev->stats.rx_errors++;
457 sixpack_decode(sp, cp, count1);
464 * Try to resync the TNC. Called by the resync timer defined in
465 * decode_prio_command
468 #define TNC_UNINITIALIZED 0
469 #define TNC_UNSYNC_STARTUP 1
470 #define TNC_UNSYNCED 2
471 #define TNC_IN_SYNC 3
473 static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
477 switch (new_tnc_state) {
478 default: /* gcc oh piece-o-crap ... */
479 case TNC_UNSYNC_STARTUP:
480 msg = "Synchronizing with TNC";
483 msg = "Lost synchronization with TNC\n";
490 sp->tnc_state = new_tnc_state;
491 printk(KERN_INFO "%s: %s\n", sp->dev->name, msg);
494 static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
496 int old_tnc_state = sp->tnc_state;
498 if (old_tnc_state != new_tnc_state)
499 __tnc_set_sync_state(sp, new_tnc_state);
502 static void resync_tnc(struct timer_list *t)
504 struct sixpack *sp = from_timer(sp, t, resync_t);
505 static char resync_cmd = 0xe8;
507 /* clear any data that might have been received */
510 sp->rx_count_cooked = 0;
512 /* reset state machine */
520 sp->led_state = 0x60;
521 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
522 sp->tty->ops->write(sp->tty, &resync_cmd, 1);
525 /* Start resync timer again -- the TNC might be still absent */
526 mod_timer(&sp->resync_t, jiffies + SIXP_RESYNC_TIMEOUT);
529 static inline int tnc_init(struct sixpack *sp)
531 unsigned char inbyte = 0xe8;
533 tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP);
535 sp->tty->ops->write(sp->tty, &inbyte, 1);
537 mod_timer(&sp->resync_t, jiffies + SIXP_RESYNC_TIMEOUT);
543 * Open the high-level part of the 6pack channel.
544 * This function is called by the TTY module when the
545 * 6pack line discipline is called for. Because we are
546 * sure the tty line exists, we only have to link it to
547 * a free 6pcack channel...
549 static int sixpack_open(struct tty_struct *tty)
551 char *rbuff = NULL, *xbuff = NULL;
552 struct net_device *dev;
557 if (!capable(CAP_NET_ADMIN))
559 if (tty->ops->write == NULL)
562 dev = alloc_netdev(sizeof(struct sixpack), "sp%d", NET_NAME_UNKNOWN,
569 sp = netdev_priv(dev);
572 spin_lock_init(&sp->lock);
573 refcount_set(&sp->refcnt, 1);
574 init_completion(&sp->dead);
576 /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */
580 rbuff = kmalloc(len + 4, GFP_KERNEL);
581 xbuff = kmalloc(len + 4, GFP_KERNEL);
583 if (rbuff == NULL || xbuff == NULL) {
588 spin_lock_bh(&sp->lock);
595 sp->mtu = AX25_MTU + 73;
599 sp->rx_count_cooked = 0;
602 sp->flags = 0; /* Clear ESCAPE & ERROR flags */
605 sp->tx_delay = SIXP_TXDELAY;
606 sp->persistence = SIXP_PERSIST;
607 sp->slottime = SIXP_SLOTTIME;
608 sp->led_state = 0x60;
614 netif_start_queue(dev);
616 timer_setup(&sp->tx_t, sp_xmit_on_air, 0);
618 timer_setup(&sp->resync_t, resync_tnc, 0);
620 spin_unlock_bh(&sp->lock);
622 /* Done. We have linked the TTY line to a channel. */
624 tty->receive_room = 65536;
626 /* Now we're ready to register. */
627 err = register_netdev(dev);
647 * Close down a 6pack channel.
648 * This means flushing out any pending queues, and then restoring the
649 * TTY line discipline to what it was before it got hooked to 6pack
650 * (which usually is TTY again).
652 static void sixpack_close(struct tty_struct *tty)
656 write_lock_bh(&disc_data_lock);
658 tty->disc_data = NULL;
659 write_unlock_bh(&disc_data_lock);
664 * We have now ensured that nobody can start using ap from now on, but
665 * we have to wait for all existing users to finish.
667 if (!refcount_dec_and_test(&sp->refcnt))
668 wait_for_completion(&sp->dead);
670 /* We must stop the queue to avoid potentially scribbling
671 * on the free buffers. The sp->dead completion is not sufficient
672 * to protect us from sp->xbuff access.
674 netif_stop_queue(sp->dev);
676 del_timer_sync(&sp->tx_t);
677 del_timer_sync(&sp->resync_t);
679 /* Free all 6pack frame buffers. */
683 unregister_netdev(sp->dev);
686 /* Perform I/O control on an active 6pack channel. */
687 static int sixpack_ioctl(struct tty_struct *tty, struct file *file,
688 unsigned int cmd, unsigned long arg)
690 struct sixpack *sp = sp_get(tty);
691 struct net_device *dev;
692 unsigned int tmp, err;
700 err = copy_to_user((void __user *) arg, dev->name,
701 strlen(dev->name) + 1) ? -EFAULT : 0;
705 err = put_user(0, (int __user *) arg);
709 if (get_user(tmp, (int __user *) arg)) {
715 dev->addr_len = AX25_ADDR_LEN;
716 dev->hard_header_len = AX25_KISS_HEADER_LEN +
717 AX25_MAX_HEADER_LEN + 3;
718 dev->type = ARPHRD_AX25;
723 case SIOCSIFHWADDR: {
724 char addr[AX25_ADDR_LEN];
726 if (copy_from_user(&addr,
727 (void __user *) arg, AX25_ADDR_LEN)) {
732 netif_tx_lock_bh(dev);
733 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN);
734 netif_tx_unlock_bh(dev);
741 err = tty_mode_ioctl(tty, file, cmd, arg);
749 static struct tty_ldisc_ops sp_ldisc = {
750 .owner = THIS_MODULE,
751 .magic = TTY_LDISC_MAGIC,
753 .open = sixpack_open,
754 .close = sixpack_close,
755 .ioctl = sixpack_ioctl,
756 .receive_buf = sixpack_receive_buf,
757 .write_wakeup = sixpack_write_wakeup,
760 /* Initialize 6pack control device -- register 6pack line discipline */
762 static const char msg_banner[] __initconst = KERN_INFO \
763 "AX.25: 6pack driver, " SIXPACK_VERSION "\n";
764 static const char msg_regfail[] __initconst = KERN_ERR \
765 "6pack: can't register line discipline (err = %d)\n";
767 static int __init sixpack_init_driver(void)
773 /* Register the provided line protocol discipline */
774 if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0)
775 printk(msg_regfail, status);
780 static const char msg_unregfail[] = KERN_ERR \
781 "6pack: can't unregister line discipline (err = %d)\n";
783 static void __exit sixpack_exit_driver(void)
787 if ((ret = tty_unregister_ldisc(N_6PACK)))
788 printk(msg_unregfail, ret);
791 /* encode an AX.25 packet into 6pack */
793 static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw,
794 int length, unsigned char tx_delay)
797 unsigned char checksum = 0, buf[400];
800 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK;
801 tx_buf_raw[raw_count++] = SIXP_SEOF;
804 for (count = 1; count < length; count++)
805 buf[count] = tx_buf[count];
807 for (count = 0; count < length; count++)
808 checksum += buf[count];
809 buf[length] = (unsigned char) 0xff - checksum;
811 for (count = 0; count <= length; count++) {
812 if ((count % 3) == 0) {
813 tx_buf_raw[raw_count++] = (buf[count] & 0x3f);
814 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30);
815 } else if ((count % 3) == 1) {
816 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f);
817 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c);
819 tx_buf_raw[raw_count++] |= (buf[count] & 0x03);
820 tx_buf_raw[raw_count++] = (buf[count] >> 2);
823 if ((length % 3) != 2)
825 tx_buf_raw[raw_count++] = SIXP_SEOF;
829 /* decode 4 sixpack-encoded bytes into 3 data bytes */
831 static void decode_data(struct sixpack *sp, unsigned char inbyte)
835 if (sp->rx_count != 3) {
836 sp->raw_buf[sp->rx_count++] = inbyte;
842 sp->cooked_buf[sp->rx_count_cooked++] =
843 buf[0] | ((buf[1] << 2) & 0xc0);
844 sp->cooked_buf[sp->rx_count_cooked++] =
845 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0);
846 sp->cooked_buf[sp->rx_count_cooked++] =
847 (buf[2] & 0x03) | (inbyte << 2);
851 /* identify and execute a 6pack priority command byte */
853 static void decode_prio_command(struct sixpack *sp, unsigned char cmd)
857 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */
859 /* RX and DCD flags can only be set in the same prio command,
860 if the DCD flag has been set without the RX flag in the previous
861 prio command. If DCD has not been set before, something in the
862 transmission has gone wrong. In this case, RX and DCD are
863 cleared in order to prevent the decode_data routine from
864 reading further data that might be corrupt. */
866 if (((sp->status & SIXP_DCD_MASK) == 0) &&
867 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) {
869 printk(KERN_DEBUG "6pack: protocol violation\n");
872 cmd &= ~SIXP_RX_DCD_MASK;
874 sp->status = cmd & SIXP_PRIO_DATA_MASK;
875 } else { /* output watchdog char if idle */
876 if ((sp->status2 != 0) && (sp->duplex == 1)) {
877 sp->led_state = 0x70;
878 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
880 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
883 sp->led_state = 0x60;
889 /* needed to trigger the TNC watchdog */
890 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
892 /* if the state byte has been received, the TNC is present,
893 so the resync timer can be reset. */
895 if (sp->tnc_state == TNC_IN_SYNC)
896 mod_timer(&sp->resync_t, jiffies + SIXP_INIT_RESYNC_TIMEOUT);
898 sp->status1 = cmd & SIXP_PRIO_DATA_MASK;
901 /* identify and execute a standard 6pack command byte */
903 static void decode_std_command(struct sixpack *sp, unsigned char cmd)
905 unsigned char checksum = 0, rest = 0;
908 switch (cmd & SIXP_CMD_MASK) { /* normal command */
910 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) {
911 if ((sp->status & SIXP_RX_DCD_MASK) ==
913 sp->led_state = 0x68;
914 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
917 sp->led_state = 0x60;
918 /* fill trailing bytes with zeroes */
919 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
922 for (i = rest; i <= 3; i++)
925 sp->rx_count_cooked -= 2;
927 sp->rx_count_cooked -= 1;
928 for (i = 0; i < sp->rx_count_cooked; i++)
929 checksum += sp->cooked_buf[i];
930 if (checksum != SIXP_CHKSUM) {
931 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum);
933 sp->rcount = sp->rx_count_cooked-2;
936 sp->rx_count_cooked = 0;
939 case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n");
941 case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n");
943 case SIXP_RX_BUF_OVL:
944 printk(KERN_DEBUG "6pack: RX buffer overflow\n");
948 /* decode a 6pack packet */
951 sixpack_decode(struct sixpack *sp, const unsigned char *pre_rbuff, int count)
953 unsigned char inbyte;
956 for (count1 = 0; count1 < count; count1++) {
957 inbyte = pre_rbuff[count1];
958 if (inbyte == SIXP_FOUND_TNC) {
959 tnc_set_sync_state(sp, TNC_IN_SYNC);
960 del_timer(&sp->resync_t);
962 if ((inbyte & SIXP_PRIO_CMD_MASK) != 0)
963 decode_prio_command(sp, inbyte);
964 else if ((inbyte & SIXP_STD_CMD_MASK) != 0)
965 decode_std_command(sp, inbyte);
966 else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)
967 decode_data(sp, inbyte);
971 MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>");
972 MODULE_DESCRIPTION("6pack driver for AX.25");
973 MODULE_LICENSE("GPL");
974 MODULE_ALIAS_LDISC(N_6PACK);
976 module_init(sixpack_init_driver);
977 module_exit(sixpack_exit_driver);