1 // SPDX-License-Identifier: GPL-2.0-only
3 * 6pack.c This module implements the 6pack protocol for kernel-based
4 * devices like TTY. It interfaces between a raw TTY and the
5 * kernel's AX.25 protocol layers.
7 * Authors: Andreas Könsgen <ajk@comnets.uni-bremen.de>
8 * Ralf Baechle DL5RB <ralf@linux-mips.org>
10 * Quite a lot of stuff "stolen" by Joerg Reuter from slip.c, written by
12 * Laurence Culhane, <loz@holmes.demon.co.uk>
13 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
16 #include <linux/module.h>
17 #include <linux/uaccess.h>
18 #include <linux/bitops.h>
19 #include <linux/string.h>
21 #include <linux/interrupt.h>
23 #include <linux/tty.h>
24 #include <linux/errno.h>
25 #include <linux/netdevice.h>
26 #include <linux/timer.h>
27 #include <linux/slab.h>
29 #include <linux/etherdevice.h>
30 #include <linux/skbuff.h>
31 #include <linux/rtnetlink.h>
32 #include <linux/spinlock.h>
33 #include <linux/if_arp.h>
34 #include <linux/init.h>
36 #include <linux/tcp.h>
37 #include <linux/semaphore.h>
38 #include <linux/refcount.h>
40 #define SIXPACK_VERSION "Revision: 0.3.0"
42 /* sixpack priority commands */
43 #define SIXP_SEOF 0x40 /* start and end of a 6pack frame */
44 #define SIXP_TX_URUN 0x48 /* transmit overrun */
45 #define SIXP_RX_ORUN 0x50 /* receive overrun */
46 #define SIXP_RX_BUF_OVL 0x58 /* receive buffer overflow */
48 #define SIXP_CHKSUM 0xFF /* valid checksum of a 6pack frame */
50 /* masks to get certain bits out of the status bytes sent by the TNC */
52 #define SIXP_CMD_MASK 0xC0
53 #define SIXP_CHN_MASK 0x07
54 #define SIXP_PRIO_CMD_MASK 0x80
55 #define SIXP_STD_CMD_MASK 0x40
56 #define SIXP_PRIO_DATA_MASK 0x38
57 #define SIXP_TX_MASK 0x20
58 #define SIXP_RX_MASK 0x10
59 #define SIXP_RX_DCD_MASK 0x18
60 #define SIXP_LEDS_ON 0x78
61 #define SIXP_LEDS_OFF 0x60
65 #define SIXP_FOUND_TNC 0xe9
66 #define SIXP_CON_ON 0x68
67 #define SIXP_DCD_MASK 0x08
68 #define SIXP_DAMA_OFF 0
70 /* default level 2 parameters */
71 #define SIXP_TXDELAY 25 /* 250 ms */
72 #define SIXP_PERSIST 50 /* in 256ths */
73 #define SIXP_SLOTTIME 10 /* 100 ms */
74 #define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */
75 #define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */
77 /* 6pack configuration. */
78 #define SIXP_NRUNIT 31 /* MAX number of 6pack channels */
79 #define SIXP_MTU 256 /* Default MTU */
82 SIXPF_ERROR, /* Parity, etc. error */
87 struct tty_struct *tty; /* ptr to TTY structure */
88 struct net_device *dev; /* easy for intr handling */
90 /* These are pointers to the malloc()ed frame buffers. */
91 unsigned char *rbuff; /* receiver buffer */
92 int rcount; /* received chars counter */
93 unsigned char *xbuff; /* transmitter buffer */
94 unsigned char *xhead; /* next byte to XMIT */
95 int xleft; /* bytes left in XMIT queue */
97 unsigned char raw_buf[4];
98 unsigned char cooked_buf[400];
100 unsigned int rx_count;
101 unsigned int rx_count_cooked;
103 int mtu; /* Our mtu (to spot changes!) */
104 int buffsize; /* Max buffers sizes */
106 unsigned long flags; /* Flag values/ mode etc */
107 unsigned char mode; /* 6pack mode */
110 unsigned char tx_delay;
111 unsigned char persistence;
112 unsigned char slottime;
113 unsigned char duplex;
114 unsigned char led_state;
115 unsigned char status;
116 unsigned char status1;
117 unsigned char status2;
118 unsigned char tx_enable;
119 unsigned char tnc_state;
121 struct timer_list tx_t;
122 struct timer_list resync_t;
124 struct completion dead;
128 #define AX25_6PACK_HEADER_LEN 0
130 static void sixpack_decode(struct sixpack *, const unsigned char[], int);
131 static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char);
134 * Perform the persistence/slottime algorithm for CSMA access. If the
135 * persistence check was successful, write the data to the serial driver.
136 * Note that in case of DAMA operation, the data is not sent here.
139 static void sp_xmit_on_air(struct timer_list *t)
141 struct sixpack *sp = from_timer(sp, t, tx_t);
142 int actual, when = sp->slottime;
143 static unsigned char random;
145 random = random * 17 + 41;
147 if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) {
148 sp->led_state = 0x70;
149 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
151 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
154 sp->led_state = 0x60;
155 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
158 mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100);
161 /* ----> 6pack timer interrupt handler and friends. <---- */
163 /* Encapsulate one AX.25 frame and stuff into a TTY queue. */
164 static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len)
166 unsigned char *msg, *p = icp;
169 if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */
170 msg = "oversized transmit packet!";
175 msg = "invalid KISS command";
179 if ((p[0] != 0) && (len > 2)) {
180 msg = "KISS control packet too long";
184 if ((p[0] == 0) && (len < 15)) {
185 msg = "bad AX.25 packet to transmit";
189 count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay);
190 set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
193 case 1: sp->tx_delay = p[1];
195 case 2: sp->persistence = p[1];
197 case 3: sp->slottime = p[1];
199 case 4: /* ignored */
201 case 5: sp->duplex = p[1];
209 * In case of fullduplex or DAMA operation, we don't take care about the
210 * state of the DCD or of any timers, as the determination of the
211 * correct time to send is the job of the AX.25 layer. We send
212 * immediately after data has arrived.
214 if (sp->duplex == 1) {
215 sp->led_state = 0x70;
216 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
218 actual = sp->tty->ops->write(sp->tty, sp->xbuff, count);
219 sp->xleft = count - actual;
220 sp->xhead = sp->xbuff + actual;
221 sp->led_state = 0x60;
222 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
225 sp->xhead = sp->xbuff;
227 sp_xmit_on_air(&sp->tx_t);
233 sp->dev->stats.tx_dropped++;
234 netif_start_queue(sp->dev);
236 printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg);
239 /* Encapsulate an IP datagram and kick it into a TTY queue. */
241 static netdev_tx_t sp_xmit(struct sk_buff *skb, struct net_device *dev)
243 struct sixpack *sp = netdev_priv(dev);
245 if (skb->protocol == htons(ETH_P_IP))
246 return ax25_ip_xmit(skb);
248 spin_lock_bh(&sp->lock);
249 /* We were not busy, so we are now... :-) */
250 netif_stop_queue(dev);
251 dev->stats.tx_bytes += skb->len;
252 sp_encaps(sp, skb->data, skb->len);
253 spin_unlock_bh(&sp->lock);
260 static int sp_open_dev(struct net_device *dev)
262 struct sixpack *sp = netdev_priv(dev);
269 /* Close the low-level part of the 6pack channel. */
270 static int sp_close(struct net_device *dev)
272 struct sixpack *sp = netdev_priv(dev);
274 spin_lock_bh(&sp->lock);
276 /* TTY discipline is running. */
277 clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
279 netif_stop_queue(dev);
280 spin_unlock_bh(&sp->lock);
285 static int sp_set_mac_address(struct net_device *dev, void *addr)
287 struct sockaddr_ax25 *sa = addr;
289 netif_tx_lock_bh(dev);
290 netif_addr_lock(dev);
291 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
292 netif_addr_unlock(dev);
293 netif_tx_unlock_bh(dev);
298 static const struct net_device_ops sp_netdev_ops = {
299 .ndo_open = sp_open_dev,
300 .ndo_stop = sp_close,
301 .ndo_start_xmit = sp_xmit,
302 .ndo_set_mac_address = sp_set_mac_address,
305 static void sp_setup(struct net_device *dev)
307 /* Finish setting up the DEVICE info. */
308 dev->netdev_ops = &sp_netdev_ops;
310 dev->hard_header_len = AX25_MAX_HEADER_LEN;
311 dev->header_ops = &ax25_header_ops;
313 dev->addr_len = AX25_ADDR_LEN;
314 dev->type = ARPHRD_AX25;
315 dev->tx_queue_len = 10;
317 /* Only activated in AX.25 mode */
318 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
319 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
324 /* Send one completely decapsulated IP datagram to the IP layer. */
327 * This is the routine that sends the received data to the kernel AX.25.
328 * 'cmd' is the KISS command. For AX.25 data, it is zero.
331 static void sp_bump(struct sixpack *sp, char cmd)
337 count = sp->rcount + 1;
339 sp->dev->stats.rx_bytes += count;
341 if ((skb = dev_alloc_skb(count + 1)) == NULL)
344 ptr = skb_put(skb, count + 1);
345 *ptr++ = cmd; /* KISS command */
347 memcpy(ptr, sp->cooked_buf + 1, count);
348 skb->protocol = ax25_type_trans(skb, sp->dev);
350 sp->dev->stats.rx_packets++;
355 sp->dev->stats.rx_dropped++;
359 /* ----------------------------------------------------------------------- */
362 * We have a potential race on dereferencing tty->disc_data, because the tty
363 * layer provides no locking at all - thus one cpu could be running
364 * sixpack_receive_buf while another calls sixpack_close, which zeroes
365 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
366 * best way to fix this is to use a rwlock in the tty struct, but for now we
367 * use a single global rwlock for all ttys in ppp line discipline.
369 static DEFINE_RWLOCK(disc_data_lock);
371 static struct sixpack *sp_get(struct tty_struct *tty)
375 read_lock(&disc_data_lock);
378 refcount_inc(&sp->refcnt);
379 read_unlock(&disc_data_lock);
384 static void sp_put(struct sixpack *sp)
386 if (refcount_dec_and_test(&sp->refcnt))
391 * Called by the TTY driver when there's room for more data. If we have
392 * more packets to send, we send them here.
394 static void sixpack_write_wakeup(struct tty_struct *tty)
396 struct sixpack *sp = sp_get(tty);
401 if (sp->xleft <= 0) {
402 /* Now serial buffer is almost free & we can start
403 * transmission of another packet */
404 sp->dev->stats.tx_packets++;
405 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
407 netif_wake_queue(sp->dev);
412 actual = tty->ops->write(tty, sp->xhead, sp->xleft);
421 /* ----------------------------------------------------------------------- */
424 * Handle the 'receiver data ready' interrupt.
425 * This function is called by the tty module in the kernel when
426 * a block of 6pack data has been received, which can now be decapsulated
427 * and sent on to some IP layer for further processing.
429 static void sixpack_receive_buf(struct tty_struct *tty,
430 const unsigned char *cp, const char *fp, int count)
442 /* Read the characters out of the buffer */
447 if (!test_and_set_bit(SIXPF_ERROR, &sp->flags))
448 sp->dev->stats.rx_errors++;
452 sixpack_decode(sp, cp, count1);
459 * Try to resync the TNC. Called by the resync timer defined in
460 * decode_prio_command
463 #define TNC_UNINITIALIZED 0
464 #define TNC_UNSYNC_STARTUP 1
465 #define TNC_UNSYNCED 2
466 #define TNC_IN_SYNC 3
468 static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
472 switch (new_tnc_state) {
473 default: /* gcc oh piece-o-crap ... */
474 case TNC_UNSYNC_STARTUP:
475 msg = "Synchronizing with TNC";
478 msg = "Lost synchronization with TNC\n";
485 sp->tnc_state = new_tnc_state;
486 printk(KERN_INFO "%s: %s\n", sp->dev->name, msg);
489 static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
491 int old_tnc_state = sp->tnc_state;
493 if (old_tnc_state != new_tnc_state)
494 __tnc_set_sync_state(sp, new_tnc_state);
497 static void resync_tnc(struct timer_list *t)
499 struct sixpack *sp = from_timer(sp, t, resync_t);
500 static char resync_cmd = 0xe8;
502 /* clear any data that might have been received */
505 sp->rx_count_cooked = 0;
507 /* reset state machine */
515 sp->led_state = 0x60;
516 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
517 sp->tty->ops->write(sp->tty, &resync_cmd, 1);
520 /* Start resync timer again -- the TNC might be still absent */
521 mod_timer(&sp->resync_t, jiffies + SIXP_RESYNC_TIMEOUT);
524 static inline int tnc_init(struct sixpack *sp)
526 unsigned char inbyte = 0xe8;
528 tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP);
530 sp->tty->ops->write(sp->tty, &inbyte, 1);
532 mod_timer(&sp->resync_t, jiffies + SIXP_RESYNC_TIMEOUT);
538 * Open the high-level part of the 6pack channel.
539 * This function is called by the TTY module when the
540 * 6pack line discipline is called for. Because we are
541 * sure the tty line exists, we only have to link it to
542 * a free 6pcack channel...
544 static int sixpack_open(struct tty_struct *tty)
546 char *rbuff = NULL, *xbuff = NULL;
547 struct net_device *dev;
552 if (!capable(CAP_NET_ADMIN))
554 if (tty->ops->write == NULL)
557 dev = alloc_netdev(sizeof(struct sixpack), "sp%d", NET_NAME_UNKNOWN,
564 sp = netdev_priv(dev);
567 spin_lock_init(&sp->lock);
568 refcount_set(&sp->refcnt, 1);
569 init_completion(&sp->dead);
571 /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */
575 rbuff = kmalloc(len + 4, GFP_KERNEL);
576 xbuff = kmalloc(len + 4, GFP_KERNEL);
578 if (rbuff == NULL || xbuff == NULL) {
583 spin_lock_bh(&sp->lock);
590 sp->mtu = AX25_MTU + 73;
594 sp->rx_count_cooked = 0;
597 sp->flags = 0; /* Clear ESCAPE & ERROR flags */
600 sp->tx_delay = SIXP_TXDELAY;
601 sp->persistence = SIXP_PERSIST;
602 sp->slottime = SIXP_SLOTTIME;
603 sp->led_state = 0x60;
609 netif_start_queue(dev);
611 timer_setup(&sp->tx_t, sp_xmit_on_air, 0);
613 timer_setup(&sp->resync_t, resync_tnc, 0);
615 spin_unlock_bh(&sp->lock);
617 /* Done. We have linked the TTY line to a channel. */
619 tty->receive_room = 65536;
621 /* Now we're ready to register. */
622 err = register_netdev(dev);
642 * Close down a 6pack channel.
643 * This means flushing out any pending queues, and then restoring the
644 * TTY line discipline to what it was before it got hooked to 6pack
645 * (which usually is TTY again).
647 static void sixpack_close(struct tty_struct *tty)
651 write_lock_irq(&disc_data_lock);
653 tty->disc_data = NULL;
654 write_unlock_irq(&disc_data_lock);
659 * We have now ensured that nobody can start using ap from now on, but
660 * we have to wait for all existing users to finish.
662 if (!refcount_dec_and_test(&sp->refcnt))
663 wait_for_completion(&sp->dead);
665 /* We must stop the queue to avoid potentially scribbling
666 * on the free buffers. The sp->dead completion is not sufficient
667 * to protect us from sp->xbuff access.
669 netif_stop_queue(sp->dev);
671 unregister_netdev(sp->dev);
673 del_timer_sync(&sp->tx_t);
674 del_timer_sync(&sp->resync_t);
676 /* Free all 6pack frame buffers after unreg. */
680 free_netdev(sp->dev);
683 /* Perform I/O control on an active 6pack channel. */
684 static int sixpack_ioctl(struct tty_struct *tty, struct file *file,
685 unsigned int cmd, unsigned long arg)
687 struct sixpack *sp = sp_get(tty);
688 struct net_device *dev;
689 unsigned int tmp, err;
697 err = copy_to_user((void __user *) arg, dev->name,
698 strlen(dev->name) + 1) ? -EFAULT : 0;
702 err = put_user(0, (int __user *) arg);
706 if (get_user(tmp, (int __user *) arg)) {
712 dev->addr_len = AX25_ADDR_LEN;
713 dev->hard_header_len = AX25_KISS_HEADER_LEN +
714 AX25_MAX_HEADER_LEN + 3;
715 dev->type = ARPHRD_AX25;
720 case SIOCSIFHWADDR: {
721 char addr[AX25_ADDR_LEN];
723 if (copy_from_user(&addr,
724 (void __user *)arg, AX25_ADDR_LEN)) {
729 netif_tx_lock_bh(dev);
730 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN);
731 netif_tx_unlock_bh(dev);
736 err = tty_mode_ioctl(tty, file, cmd, arg);
744 static struct tty_ldisc_ops sp_ldisc = {
745 .owner = THIS_MODULE,
748 .open = sixpack_open,
749 .close = sixpack_close,
750 .ioctl = sixpack_ioctl,
751 .receive_buf = sixpack_receive_buf,
752 .write_wakeup = sixpack_write_wakeup,
755 /* Initialize 6pack control device -- register 6pack line discipline */
757 static const char msg_banner[] __initconst = KERN_INFO \
758 "AX.25: 6pack driver, " SIXPACK_VERSION "\n";
759 static const char msg_regfail[] __initconst = KERN_ERR \
760 "6pack: can't register line discipline (err = %d)\n";
762 static int __init sixpack_init_driver(void)
768 /* Register the provided line protocol discipline */
769 status = tty_register_ldisc(&sp_ldisc);
771 printk(msg_regfail, status);
776 static void __exit sixpack_exit_driver(void)
778 tty_unregister_ldisc(&sp_ldisc);
781 /* encode an AX.25 packet into 6pack */
783 static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw,
784 int length, unsigned char tx_delay)
787 unsigned char checksum = 0, buf[400];
790 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK;
791 tx_buf_raw[raw_count++] = SIXP_SEOF;
794 for (count = 1; count < length; count++)
795 buf[count] = tx_buf[count];
797 for (count = 0; count < length; count++)
798 checksum += buf[count];
799 buf[length] = (unsigned char) 0xff - checksum;
801 for (count = 0; count <= length; count++) {
802 if ((count % 3) == 0) {
803 tx_buf_raw[raw_count++] = (buf[count] & 0x3f);
804 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30);
805 } else if ((count % 3) == 1) {
806 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f);
807 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c);
809 tx_buf_raw[raw_count++] |= (buf[count] & 0x03);
810 tx_buf_raw[raw_count++] = (buf[count] >> 2);
813 if ((length % 3) != 2)
815 tx_buf_raw[raw_count++] = SIXP_SEOF;
819 /* decode 4 sixpack-encoded bytes into 3 data bytes */
821 static void decode_data(struct sixpack *sp, unsigned char inbyte)
825 if (sp->rx_count != 3) {
826 sp->raw_buf[sp->rx_count++] = inbyte;
831 if (sp->rx_count_cooked + 2 >= sizeof(sp->cooked_buf)) {
832 pr_err("6pack: cooked buffer overrun, data loss\n");
838 sp->cooked_buf[sp->rx_count_cooked++] =
839 buf[0] | ((buf[1] << 2) & 0xc0);
840 sp->cooked_buf[sp->rx_count_cooked++] =
841 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0);
842 sp->cooked_buf[sp->rx_count_cooked++] =
843 (buf[2] & 0x03) | (inbyte << 2);
847 /* identify and execute a 6pack priority command byte */
849 static void decode_prio_command(struct sixpack *sp, unsigned char cmd)
853 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */
855 /* RX and DCD flags can only be set in the same prio command,
856 if the DCD flag has been set without the RX flag in the previous
857 prio command. If DCD has not been set before, something in the
858 transmission has gone wrong. In this case, RX and DCD are
859 cleared in order to prevent the decode_data routine from
860 reading further data that might be corrupt. */
862 if (((sp->status & SIXP_DCD_MASK) == 0) &&
863 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) {
865 printk(KERN_DEBUG "6pack: protocol violation\n");
868 cmd &= ~SIXP_RX_DCD_MASK;
870 sp->status = cmd & SIXP_PRIO_DATA_MASK;
871 } else { /* output watchdog char if idle */
872 if ((sp->status2 != 0) && (sp->duplex == 1)) {
873 sp->led_state = 0x70;
874 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
876 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
879 sp->led_state = 0x60;
885 /* needed to trigger the TNC watchdog */
886 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
888 /* if the state byte has been received, the TNC is present,
889 so the resync timer can be reset. */
891 if (sp->tnc_state == TNC_IN_SYNC)
892 mod_timer(&sp->resync_t, jiffies + SIXP_INIT_RESYNC_TIMEOUT);
894 sp->status1 = cmd & SIXP_PRIO_DATA_MASK;
897 /* identify and execute a standard 6pack command byte */
899 static void decode_std_command(struct sixpack *sp, unsigned char cmd)
901 unsigned char checksum = 0, rest = 0;
904 switch (cmd & SIXP_CMD_MASK) { /* normal command */
906 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) {
907 if ((sp->status & SIXP_RX_DCD_MASK) ==
909 sp->led_state = 0x68;
910 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
913 sp->led_state = 0x60;
914 /* fill trailing bytes with zeroes */
915 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
918 for (i = rest; i <= 3; i++)
921 sp->rx_count_cooked -= 2;
923 sp->rx_count_cooked -= 1;
924 for (i = 0; i < sp->rx_count_cooked; i++)
925 checksum += sp->cooked_buf[i];
926 if (checksum != SIXP_CHKSUM) {
927 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum);
929 sp->rcount = sp->rx_count_cooked-2;
932 sp->rx_count_cooked = 0;
935 case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n");
937 case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n");
939 case SIXP_RX_BUF_OVL:
940 printk(KERN_DEBUG "6pack: RX buffer overflow\n");
944 /* decode a 6pack packet */
947 sixpack_decode(struct sixpack *sp, const unsigned char *pre_rbuff, int count)
949 unsigned char inbyte;
952 for (count1 = 0; count1 < count; count1++) {
953 inbyte = pre_rbuff[count1];
954 if (inbyte == SIXP_FOUND_TNC) {
955 tnc_set_sync_state(sp, TNC_IN_SYNC);
956 del_timer(&sp->resync_t);
958 if ((inbyte & SIXP_PRIO_CMD_MASK) != 0)
959 decode_prio_command(sp, inbyte);
960 else if ((inbyte & SIXP_STD_CMD_MASK) != 0)
961 decode_std_command(sp, inbyte);
962 else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)
963 decode_data(sp, inbyte);
967 MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>");
968 MODULE_DESCRIPTION("6pack driver for AX.25");
969 MODULE_LICENSE("GPL");
970 MODULE_ALIAS_LDISC(N_6PACK);
972 module_init(sixpack_init_driver);
973 module_exit(sixpack_exit_driver);