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;
104 int mtu; /* Our mtu (to spot changes!) */
105 int buffsize; /* Max buffers sizes */
107 unsigned long flags; /* Flag values/ mode etc */
108 unsigned char mode; /* 6pack mode */
111 unsigned char tx_delay;
112 unsigned char persistence;
113 unsigned char slottime;
114 unsigned char duplex;
115 unsigned char led_state;
116 unsigned char status;
117 unsigned char status1;
118 unsigned char status2;
119 unsigned char tx_enable;
120 unsigned char tnc_state;
122 struct timer_list tx_t;
123 struct timer_list resync_t;
125 struct completion dead;
129 #define AX25_6PACK_HEADER_LEN 0
131 static void sixpack_decode(struct sixpack *, const unsigned char[], int);
132 static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char);
135 * Perform the persistence/slottime algorithm for CSMA access. If the
136 * persistence check was successful, write the data to the serial driver.
137 * Note that in case of DAMA operation, the data is not sent here.
140 static void sp_xmit_on_air(struct timer_list *t)
142 struct sixpack *sp = from_timer(sp, t, tx_t);
143 int actual, when = sp->slottime;
144 static unsigned char random;
146 random = random * 17 + 41;
148 if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) {
149 sp->led_state = 0x70;
150 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
152 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
155 sp->led_state = 0x60;
156 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
159 mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100);
162 /* ----> 6pack timer interrupt handler and friends. <---- */
164 /* Encapsulate one AX.25 frame and stuff into a TTY queue. */
165 static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len)
167 unsigned char *msg, *p = icp;
170 if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */
171 msg = "oversized transmit packet!";
176 msg = "invalid KISS command";
180 if ((p[0] != 0) && (len > 2)) {
181 msg = "KISS control packet too long";
185 if ((p[0] == 0) && (len < 15)) {
186 msg = "bad AX.25 packet to transmit";
190 count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay);
191 set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
194 case 1: sp->tx_delay = p[1];
196 case 2: sp->persistence = p[1];
198 case 3: sp->slottime = p[1];
200 case 4: /* ignored */
202 case 5: sp->duplex = p[1];
210 * In case of fullduplex or DAMA operation, we don't take care about the
211 * state of the DCD or of any timers, as the determination of the
212 * correct time to send is the job of the AX.25 layer. We send
213 * immediately after data has arrived.
215 if (sp->duplex == 1) {
216 sp->led_state = 0x70;
217 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
219 actual = sp->tty->ops->write(sp->tty, sp->xbuff, count);
220 sp->xleft = count - actual;
221 sp->xhead = sp->xbuff + actual;
222 sp->led_state = 0x60;
223 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
226 sp->xhead = sp->xbuff;
228 sp_xmit_on_air(&sp->tx_t);
234 sp->dev->stats.tx_dropped++;
235 netif_start_queue(sp->dev);
237 printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg);
240 /* Encapsulate an IP datagram and kick it into a TTY queue. */
242 static netdev_tx_t sp_xmit(struct sk_buff *skb, struct net_device *dev)
244 struct sixpack *sp = netdev_priv(dev);
246 if (skb->protocol == htons(ETH_P_IP))
247 return ax25_ip_xmit(skb);
249 spin_lock_bh(&sp->lock);
250 /* We were not busy, so we are now... :-) */
251 netif_stop_queue(dev);
252 dev->stats.tx_bytes += skb->len;
253 sp_encaps(sp, skb->data, skb->len);
254 spin_unlock_bh(&sp->lock);
261 static int sp_open_dev(struct net_device *dev)
263 struct sixpack *sp = netdev_priv(dev);
270 /* Close the low-level part of the 6pack channel. */
271 static int sp_close(struct net_device *dev)
273 struct sixpack *sp = netdev_priv(dev);
275 spin_lock_bh(&sp->lock);
277 /* TTY discipline is running. */
278 clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
280 netif_stop_queue(dev);
281 spin_unlock_bh(&sp->lock);
286 static int sp_set_mac_address(struct net_device *dev, void *addr)
288 struct sockaddr_ax25 *sa = addr;
290 netif_tx_lock_bh(dev);
291 netif_addr_lock(dev);
292 __dev_addr_set(dev, &sa->sax25_call, AX25_ADDR_LEN);
293 netif_addr_unlock(dev);
294 netif_tx_unlock_bh(dev);
299 static const struct net_device_ops sp_netdev_ops = {
300 .ndo_open = sp_open_dev,
301 .ndo_stop = sp_close,
302 .ndo_start_xmit = sp_xmit,
303 .ndo_set_mac_address = sp_set_mac_address,
306 static void sp_setup(struct net_device *dev)
308 /* Finish setting up the DEVICE info. */
309 dev->netdev_ops = &sp_netdev_ops;
311 dev->hard_header_len = AX25_MAX_HEADER_LEN;
312 dev->header_ops = &ax25_header_ops;
314 dev->addr_len = AX25_ADDR_LEN;
315 dev->type = ARPHRD_AX25;
316 dev->tx_queue_len = 10;
318 /* Only activated in AX.25 mode */
319 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
320 dev_addr_set(dev, (u8 *)&ax25_defaddr);
325 /* Send one completely decapsulated IP datagram to the IP layer. */
328 * This is the routine that sends the received data to the kernel AX.25.
329 * 'cmd' is the KISS command. For AX.25 data, it is zero.
332 static void sp_bump(struct sixpack *sp, char cmd)
338 count = sp->rcount + 1;
340 sp->dev->stats.rx_bytes += count;
342 if ((skb = dev_alloc_skb(count + 1)) == NULL)
345 ptr = skb_put(skb, count + 1);
346 *ptr++ = cmd; /* KISS command */
348 memcpy(ptr, sp->cooked_buf + 1, count);
349 skb->protocol = ax25_type_trans(skb, sp->dev);
351 sp->dev->stats.rx_packets++;
356 sp->dev->stats.rx_dropped++;
360 /* ----------------------------------------------------------------------- */
363 * We have a potential race on dereferencing tty->disc_data, because the tty
364 * layer provides no locking at all - thus one cpu could be running
365 * sixpack_receive_buf while another calls sixpack_close, which zeroes
366 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
367 * best way to fix this is to use a rwlock in the tty struct, but for now we
368 * use a single global rwlock for all ttys in ppp line discipline.
370 static DEFINE_RWLOCK(disc_data_lock);
372 static struct sixpack *sp_get(struct tty_struct *tty)
376 read_lock(&disc_data_lock);
379 refcount_inc(&sp->refcnt);
380 read_unlock(&disc_data_lock);
385 static void sp_put(struct sixpack *sp)
387 if (refcount_dec_and_test(&sp->refcnt))
392 * Called by the TTY driver when there's room for more data. If we have
393 * more packets to send, we send them here.
395 static void sixpack_write_wakeup(struct tty_struct *tty)
397 struct sixpack *sp = sp_get(tty);
402 if (sp->xleft <= 0) {
403 /* Now serial buffer is almost free & we can start
404 * transmission of another packet */
405 sp->dev->stats.tx_packets++;
406 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
408 netif_wake_queue(sp->dev);
413 actual = tty->ops->write(tty, sp->xhead, sp->xleft);
422 /* ----------------------------------------------------------------------- */
425 * Handle the 'receiver data ready' interrupt.
426 * This function is called by the tty module in the kernel when
427 * a block of 6pack data has been received, which can now be decapsulated
428 * and sent on to some IP layer for further processing.
430 static void sixpack_receive_buf(struct tty_struct *tty,
431 const unsigned char *cp, const char *fp, int count)
443 /* Read the characters out of the buffer */
448 if (!test_and_set_bit(SIXPF_ERROR, &sp->flags))
449 sp->dev->stats.rx_errors++;
453 sixpack_decode(sp, cp, count1);
460 * Try to resync the TNC. Called by the resync timer defined in
461 * decode_prio_command
464 #define TNC_UNINITIALIZED 0
465 #define TNC_UNSYNC_STARTUP 1
466 #define TNC_UNSYNCED 2
467 #define TNC_IN_SYNC 3
469 static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
473 switch (new_tnc_state) {
474 default: /* gcc oh piece-o-crap ... */
475 case TNC_UNSYNC_STARTUP:
476 msg = "Synchronizing with TNC";
479 msg = "Lost synchronization with TNC\n";
486 sp->tnc_state = new_tnc_state;
487 printk(KERN_INFO "%s: %s\n", sp->dev->name, msg);
490 static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
492 int old_tnc_state = sp->tnc_state;
494 if (old_tnc_state != new_tnc_state)
495 __tnc_set_sync_state(sp, new_tnc_state);
498 static void resync_tnc(struct timer_list *t)
500 struct sixpack *sp = from_timer(sp, t, resync_t);
501 static char resync_cmd = 0xe8;
503 /* clear any data that might have been received */
506 sp->rx_count_cooked = 0;
508 /* reset state machine */
516 sp->led_state = 0x60;
517 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
518 sp->tty->ops->write(sp->tty, &resync_cmd, 1);
521 /* Start resync timer again -- the TNC might be still absent */
522 mod_timer(&sp->resync_t, jiffies + SIXP_RESYNC_TIMEOUT);
525 static inline int tnc_init(struct sixpack *sp)
527 unsigned char inbyte = 0xe8;
529 tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP);
531 sp->tty->ops->write(sp->tty, &inbyte, 1);
533 mod_timer(&sp->resync_t, jiffies + SIXP_RESYNC_TIMEOUT);
539 * Open the high-level part of the 6pack channel.
540 * This function is called by the TTY module when the
541 * 6pack line discipline is called for. Because we are
542 * sure the tty line exists, we only have to link it to
543 * a free 6pcack channel...
545 static int sixpack_open(struct tty_struct *tty)
547 char *rbuff = NULL, *xbuff = NULL;
548 struct net_device *dev;
553 if (!capable(CAP_NET_ADMIN))
555 if (tty->ops->write == NULL)
558 dev = alloc_netdev(sizeof(struct sixpack), "sp%d", NET_NAME_UNKNOWN,
565 sp = netdev_priv(dev);
568 spin_lock_init(&sp->lock);
569 spin_lock_init(&sp->rxlock);
570 refcount_set(&sp->refcnt, 1);
571 init_completion(&sp->dead);
573 /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */
577 rbuff = kmalloc(len + 4, GFP_KERNEL);
578 xbuff = kmalloc(len + 4, GFP_KERNEL);
580 if (rbuff == NULL || xbuff == NULL) {
585 spin_lock_bh(&sp->lock);
592 sp->mtu = AX25_MTU + 73;
596 sp->rx_count_cooked = 0;
599 sp->flags = 0; /* Clear ESCAPE & ERROR flags */
602 sp->tx_delay = SIXP_TXDELAY;
603 sp->persistence = SIXP_PERSIST;
604 sp->slottime = SIXP_SLOTTIME;
605 sp->led_state = 0x60;
611 netif_start_queue(dev);
613 timer_setup(&sp->tx_t, sp_xmit_on_air, 0);
615 timer_setup(&sp->resync_t, resync_tnc, 0);
617 spin_unlock_bh(&sp->lock);
619 /* Done. We have linked the TTY line to a channel. */
621 tty->receive_room = 65536;
623 /* Now we're ready to register. */
624 err = register_netdev(dev);
644 * Close down a 6pack channel.
645 * This means flushing out any pending queues, and then restoring the
646 * TTY line discipline to what it was before it got hooked to 6pack
647 * (which usually is TTY again).
649 static void sixpack_close(struct tty_struct *tty)
653 write_lock_irq(&disc_data_lock);
655 tty->disc_data = NULL;
656 write_unlock_irq(&disc_data_lock);
661 * We have now ensured that nobody can start using ap from now on, but
662 * we have to wait for all existing users to finish.
664 if (!refcount_dec_and_test(&sp->refcnt))
665 wait_for_completion(&sp->dead);
667 /* We must stop the queue to avoid potentially scribbling
668 * on the free buffers. The sp->dead completion is not sufficient
669 * to protect us from sp->xbuff access.
671 netif_stop_queue(sp->dev);
673 unregister_netdev(sp->dev);
675 del_timer_sync(&sp->tx_t);
676 del_timer_sync(&sp->resync_t);
678 /* Free all 6pack frame buffers after unreg. */
682 free_netdev(sp->dev);
685 /* Perform I/O control on an active 6pack channel. */
686 static int sixpack_ioctl(struct tty_struct *tty, unsigned int cmd,
689 struct sixpack *sp = sp_get(tty);
690 struct net_device *dev;
691 unsigned int tmp, err;
699 err = copy_to_user((void __user *) arg, dev->name,
700 strlen(dev->name) + 1) ? -EFAULT : 0;
704 err = put_user(0, (int __user *) arg);
708 if (get_user(tmp, (int __user *) arg)) {
714 dev->addr_len = AX25_ADDR_LEN;
715 dev->hard_header_len = AX25_KISS_HEADER_LEN +
716 AX25_MAX_HEADER_LEN + 3;
717 dev->type = ARPHRD_AX25;
722 case SIOCSIFHWADDR: {
723 char addr[AX25_ADDR_LEN];
725 if (copy_from_user(&addr,
726 (void __user *)arg, AX25_ADDR_LEN)) {
731 netif_tx_lock_bh(dev);
732 __dev_addr_set(dev, &addr, AX25_ADDR_LEN);
733 netif_tx_unlock_bh(dev);
738 err = tty_mode_ioctl(tty, cmd, arg);
746 static struct tty_ldisc_ops sp_ldisc = {
747 .owner = THIS_MODULE,
750 .open = sixpack_open,
751 .close = sixpack_close,
752 .ioctl = sixpack_ioctl,
753 .receive_buf = sixpack_receive_buf,
754 .write_wakeup = sixpack_write_wakeup,
757 /* Initialize 6pack control device -- register 6pack line discipline */
759 static const char msg_banner[] __initconst = KERN_INFO \
760 "AX.25: 6pack driver, " SIXPACK_VERSION "\n";
761 static const char msg_regfail[] __initconst = KERN_ERR \
762 "6pack: can't register line discipline (err = %d)\n";
764 static int __init sixpack_init_driver(void)
770 /* Register the provided line protocol discipline */
771 status = tty_register_ldisc(&sp_ldisc);
773 printk(msg_regfail, status);
778 static void __exit sixpack_exit_driver(void)
780 tty_unregister_ldisc(&sp_ldisc);
783 /* encode an AX.25 packet into 6pack */
785 static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw,
786 int length, unsigned char tx_delay)
789 unsigned char checksum = 0, buf[400];
792 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK;
793 tx_buf_raw[raw_count++] = SIXP_SEOF;
796 for (count = 1; count < length; count++)
797 buf[count] = tx_buf[count];
799 for (count = 0; count < length; count++)
800 checksum += buf[count];
801 buf[length] = (unsigned char) 0xff - checksum;
803 for (count = 0; count <= length; count++) {
804 if ((count % 3) == 0) {
805 tx_buf_raw[raw_count++] = (buf[count] & 0x3f);
806 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30);
807 } else if ((count % 3) == 1) {
808 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f);
809 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c);
811 tx_buf_raw[raw_count++] |= (buf[count] & 0x03);
812 tx_buf_raw[raw_count++] = (buf[count] >> 2);
815 if ((length % 3) != 2)
817 tx_buf_raw[raw_count++] = SIXP_SEOF;
821 /* decode 4 sixpack-encoded bytes into 3 data bytes */
823 static void decode_data(struct sixpack *sp, unsigned char inbyte)
827 if (sp->rx_count != 3) {
828 sp->raw_buf[sp->rx_count++] = inbyte;
833 if (sp->rx_count_cooked + 2 >= sizeof(sp->cooked_buf)) {
834 pr_err("6pack: cooked buffer overrun, data loss\n");
840 sp->cooked_buf[sp->rx_count_cooked++] =
841 buf[0] | ((buf[1] << 2) & 0xc0);
842 sp->cooked_buf[sp->rx_count_cooked++] =
843 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0);
844 sp->cooked_buf[sp->rx_count_cooked++] =
845 (buf[2] & 0x03) | (inbyte << 2);
849 /* identify and execute a 6pack priority command byte */
851 static void decode_prio_command(struct sixpack *sp, unsigned char cmd)
855 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */
857 /* RX and DCD flags can only be set in the same prio command,
858 if the DCD flag has been set without the RX flag in the previous
859 prio command. If DCD has not been set before, something in the
860 transmission has gone wrong. In this case, RX and DCD are
861 cleared in order to prevent the decode_data routine from
862 reading further data that might be corrupt. */
864 if (((sp->status & SIXP_DCD_MASK) == 0) &&
865 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) {
867 printk(KERN_DEBUG "6pack: protocol violation\n");
870 cmd &= ~SIXP_RX_DCD_MASK;
872 sp->status = cmd & SIXP_PRIO_DATA_MASK;
873 } else { /* output watchdog char if idle */
874 if ((sp->status2 != 0) && (sp->duplex == 1)) {
875 sp->led_state = 0x70;
876 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
878 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
881 sp->led_state = 0x60;
887 /* needed to trigger the TNC watchdog */
888 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
890 /* if the state byte has been received, the TNC is present,
891 so the resync timer can be reset. */
893 if (sp->tnc_state == TNC_IN_SYNC)
894 mod_timer(&sp->resync_t, jiffies + SIXP_INIT_RESYNC_TIMEOUT);
896 sp->status1 = cmd & SIXP_PRIO_DATA_MASK;
899 /* identify and execute a standard 6pack command byte */
901 static void decode_std_command(struct sixpack *sp, unsigned char cmd)
903 unsigned char checksum = 0, rest = 0;
906 switch (cmd & SIXP_CMD_MASK) { /* normal command */
908 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) {
909 if ((sp->status & SIXP_RX_DCD_MASK) ==
911 sp->led_state = 0x68;
912 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
915 sp->led_state = 0x60;
916 /* fill trailing bytes with zeroes */
917 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
918 spin_lock_bh(&sp->rxlock);
921 for (i = rest; i <= 3; i++)
924 sp->rx_count_cooked -= 2;
926 sp->rx_count_cooked -= 1;
927 for (i = 0; i < sp->rx_count_cooked; i++)
928 checksum += sp->cooked_buf[i];
929 if (checksum != SIXP_CHKSUM) {
930 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum);
932 sp->rcount = sp->rx_count_cooked-2;
935 sp->rx_count_cooked = 0;
936 spin_unlock_bh(&sp->rxlock);
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 spin_lock_bh(&sp->rxlock);
968 decode_data(sp, inbyte);
969 spin_unlock_bh(&sp->rxlock);
974 MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>");
975 MODULE_DESCRIPTION("6pack driver for AX.25");
976 MODULE_LICENSE("GPL");
977 MODULE_ALIAS_LDISC(N_6PACK);
979 module_init(sixpack_init_driver);
980 module_exit(sixpack_exit_driver);