blob: 914be58473866c03a6e804b4d6beba1736e35546 [file] [log] [blame]
Thomas Gleixner09c434b2019-05-19 13:08:20 +01001// SPDX-License-Identifier: GPL-2.0-only
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * Things to sort out:
4 *
5 * o tbusy handling
6 * o allow users to set the parameters
7 * o sync/async switching ?
8 *
9 * Note: This does _not_ implement CCITT X.25 asynchronous framing
10 * recommendations. Its primarily for testing purposes. If you wanted
11 * to do CCITT then in theory all you need is to nick the HDLC async
12 * checksum routines from ppp.c
13 * Changes:
14 *
15 * 2000-10-29 Henner Eisen lapb_data_indication() return status.
16 */
17
Joe Perches23efcb72011-06-26 19:01:35 +000018#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/module.h>
21
Alan Coxf34d7a52008-04-30 00:54:13 -070022#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/bitops.h>
24#include <linux/string.h>
25#include <linux/mm.h>
26#include <linux/interrupt.h>
27#include <linux/in.h>
28#include <linux/tty.h>
29#include <linux/errno.h>
30#include <linux/netdevice.h>
31#include <linux/etherdevice.h>
32#include <linux/skbuff.h>
33#include <linux/if_arp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <linux/lapb.h>
35#include <linux/init.h>
Ben Hutchings3e3cda92008-05-06 19:41:48 +010036#include <linux/rtnetlink.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090037#include <linux/slab.h>
andrew hendry7eeeacf02010-04-19 13:29:47 +000038#include <net/x25device.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039#include "x25_asy.h"
40
Linus Torvalds1da177e2005-04-16 15:20:36 -070041static struct net_device **x25_asy_devs;
42static int x25_asy_maxdev = SL_NRUNIT;
43
44module_param(x25_asy_maxdev, int, 0);
45MODULE_LICENSE("GPL");
46
47static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
48static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
49static void x25_asy_setup(struct net_device *dev);
50
51/* Find a free X.25 channel, and link in this `tty' line. */
52static struct x25_asy *x25_asy_alloc(void)
53{
54 struct net_device *dev = NULL;
55 struct x25_asy *sl;
56 int i;
57
58 if (x25_asy_devs == NULL)
59 return NULL; /* Master array missing ! */
60
61 for (i = 0; i < x25_asy_maxdev; i++) {
62 dev = x25_asy_devs[i];
63
64 /* Not allocated ? */
65 if (dev == NULL)
66 break;
67
Wang Chen8f15ea42008-11-12 23:38:36 -080068 sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 /* Not in use ? */
70 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
71 return sl;
72 }
73
74
75 /* Sorry, too many, all slots in use */
76 if (i >= x25_asy_maxdev)
77 return NULL;
78
79 /* If no channels are available, allocate one */
80 if (!dev) {
81 char name[IFNAMSIZ];
82 sprintf(name, "x25asy%d", i);
83
Tom Gundersenc835a672014-07-14 16:37:24 +020084 dev = alloc_netdev(sizeof(struct x25_asy), name,
85 NET_NAME_UNKNOWN, x25_asy_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 if (!dev)
87 return NULL;
88
89 /* Initialize channel control data */
Wang Chen8f15ea42008-11-12 23:38:36 -080090 sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 dev->base_addr = i;
92
93 /* register device so that it can be ifconfig'ed */
94 if (register_netdev(dev) == 0) {
95 /* (Re-)Set the INUSE bit. Very Important! */
96 set_bit(SLF_INUSE, &sl->flags);
97 x25_asy_devs[i] = dev;
98 return sl;
99 } else {
Joe Perches23efcb72011-06-26 19:01:35 +0000100 pr_warn("%s(): register_netdev() failure\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 free_netdev(dev);
102 }
103 }
104 return NULL;
105}
106
107
108/* Free an X.25 channel. */
109static void x25_asy_free(struct x25_asy *sl)
110{
111 /* Free all X.25 frame buffers. */
Jesper Juhl6a5d3622005-05-03 14:33:27 -0700112 kfree(sl->rbuff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 sl->rbuff = NULL;
Jesper Juhl6a5d3622005-05-03 14:33:27 -0700114 kfree(sl->xbuff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 sl->xbuff = NULL;
116
Alan Coxf34d7a52008-04-30 00:54:13 -0700117 if (!test_and_clear_bit(SLF_INUSE, &sl->flags))
Joe Perches23efcb72011-06-26 19:01:35 +0000118 netdev_err(sl->dev, "x25_asy_free for already free unit\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119}
120
121static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
122{
Wang Chen8f15ea42008-11-12 23:38:36 -0800123 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 unsigned char *xbuff, *rbuff;
Dan Carpentera28d0e82014-07-17 13:50:45 +0300125 int len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
Dan Carpentera28d0e82014-07-17 13:50:45 +0300127 len = 2 * newmtu;
Robert P. J. Day5cbded52006-12-13 00:35:56 -0800128 xbuff = kmalloc(len + 4, GFP_ATOMIC);
129 rbuff = kmalloc(len + 4, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
Alan Coxf34d7a52008-04-30 00:54:13 -0700131 if (xbuff == NULL || rbuff == NULL) {
Jesper Juhl6a5d3622005-05-03 14:33:27 -0700132 kfree(xbuff);
133 kfree(rbuff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 return -ENOMEM;
135 }
136
137 spin_lock_bh(&sl->lock);
138 xbuff = xchg(&sl->xbuff, xbuff);
139 if (sl->xleft) {
140 if (sl->xleft <= len) {
141 memcpy(sl->xbuff, sl->xhead, sl->xleft);
142 } else {
143 sl->xleft = 0;
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000144 dev->stats.tx_dropped++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 }
146 }
147 sl->xhead = sl->xbuff;
148
149 rbuff = xchg(&sl->rbuff, rbuff);
150 if (sl->rcount) {
151 if (sl->rcount <= len) {
152 memcpy(sl->rbuff, rbuff, sl->rcount);
153 } else {
154 sl->rcount = 0;
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000155 dev->stats.rx_over_errors++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 set_bit(SLF_ERROR, &sl->flags);
157 }
158 }
159
160 dev->mtu = newmtu;
161 sl->buffsize = len;
162
163 spin_unlock_bh(&sl->lock);
164
Jesper Juhl6a5d3622005-05-03 14:33:27 -0700165 kfree(xbuff);
166 kfree(rbuff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 return 0;
168}
169
170
171/* Set the "sending" flag. This must be atomic, hence the ASM. */
172
173static inline void x25_asy_lock(struct x25_asy *sl)
174{
175 netif_stop_queue(sl->dev);
176}
177
178
179/* Clear the "sending" flag. This must be atomic, hence the ASM. */
180
181static inline void x25_asy_unlock(struct x25_asy *sl)
182{
183 netif_wake_queue(sl->dev);
184}
185
186/* Send one completely decapsulated IP datagram to the IP layer. */
187
188static void x25_asy_bump(struct x25_asy *sl)
189{
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000190 struct net_device *dev = sl->dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 struct sk_buff *skb;
192 int count;
193 int err;
194
195 count = sl->rcount;
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000196 dev->stats.rx_bytes += count;
Alan Coxf34d7a52008-04-30 00:54:13 -0700197
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 skb = dev_alloc_skb(count+1);
Alan Coxf34d7a52008-04-30 00:54:13 -0700199 if (skb == NULL) {
Joe Perches23efcb72011-06-26 19:01:35 +0000200 netdev_warn(sl->dev, "memory squeeze, dropping packet\n");
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000201 dev->stats.rx_dropped++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 return;
203 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700204 skb_push(skb, 1); /* LAPB internal control */
Johannes Berg59ae1d12017-06-16 14:29:20 +0200205 skb_put_data(skb, sl->rbuff, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 skb->protocol = x25_type_trans(skb, sl->dev);
Alan Coxf34d7a52008-04-30 00:54:13 -0700207 err = lapb_data_received(skb->dev, skb);
208 if (err != LAPB_OK) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 kfree_skb(skb);
Alan Coxf34d7a52008-04-30 00:54:13 -0700210 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
211 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 netif_rx(skb);
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000213 dev->stats.rx_packets++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 }
215}
216
217/* Encapsulate one IP datagram and stuff into a TTY queue. */
218static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
219{
220 unsigned char *p;
221 int actual, count, mtu = sl->dev->mtu;
222
Alan Coxf34d7a52008-04-30 00:54:13 -0700223 if (len > mtu) {
224 /* Sigh, shouldn't occur BUT ... */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 len = mtu;
Alan Coxf34d7a52008-04-30 00:54:13 -0700226 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
227 sl->dev->name);
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000228 sl->dev->stats.tx_dropped++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 x25_asy_unlock(sl);
230 return;
231 }
232
233 p = icp;
Joe Perchesc2fd03a2012-06-04 12:44:18 +0000234 count = x25_asy_esc(p, sl->xbuff, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
236 /* Order of next two lines is *very* important.
237 * When we are sending a little amount of data,
238 * the transfer may be completed inside driver.write()
239 * routine, because it's running with interrupts enabled.
240 * In this case we *never* got WRITE_WAKEUP event,
241 * if we did not request it before write operation.
242 * 14 Oct 1994 Dmitry Gorodchanin.
243 */
Alan Cox8a1ec212008-12-05 22:31:52 -0800244 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
Alan Coxf34d7a52008-04-30 00:54:13 -0700245 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 sl->xleft = count - actual;
247 sl->xhead = sl->xbuff + actual;
248 /* VSV */
249 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
250}
251
252/*
253 * Called by the driver when there's room for more data. If we have
254 * more packets to send, we send them here.
255 */
256static void x25_asy_write_wakeup(struct tty_struct *tty)
257{
258 int actual;
Alan Coxd2b88812008-12-05 22:32:22 -0800259 struct x25_asy *sl = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
261 /* First make sure we're connected. */
262 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
263 return;
264
Alan Coxf34d7a52008-04-30 00:54:13 -0700265 if (sl->xleft <= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 /* Now serial buffer is almost free & we can start
267 * transmission of another packet */
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000268 sl->dev->stats.tx_packets++;
Alan Cox8a1ec212008-12-05 22:31:52 -0800269 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 x25_asy_unlock(sl);
271 return;
272 }
273
Alan Coxf34d7a52008-04-30 00:54:13 -0700274 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 sl->xleft -= actual;
276 sl->xhead += actual;
277}
278
279static void x25_asy_timeout(struct net_device *dev)
280{
Wang Chen8f15ea42008-11-12 23:38:36 -0800281 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282
283 spin_lock(&sl->lock);
284 if (netif_queue_stopped(dev)) {
285 /* May be we must check transmitter timeout here ?
286 * 14 Oct 1994 Dmitry Gorodchanin.
287 */
Joe Perches23efcb72011-06-26 19:01:35 +0000288 netdev_warn(dev, "transmit timed out, %s?\n",
289 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
290 "bad line quality" : "driver error");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 sl->xleft = 0;
Alan Cox8a1ec212008-12-05 22:31:52 -0800292 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 x25_asy_unlock(sl);
294 }
295 spin_unlock(&sl->lock);
296}
297
298/* Encapsulate an IP datagram and kick it into a TTY queue. */
299
Stephen Hemmingerd71a6742009-08-31 19:50:47 +0000300static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
301 struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302{
Wang Chen8f15ea42008-11-12 23:38:36 -0800303 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 int err;
305
306 if (!netif_running(sl->dev)) {
Joe Perches23efcb72011-06-26 19:01:35 +0000307 netdev_err(dev, "xmit call when iface is down\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 kfree_skb(skb);
Patrick McHardy6ed10652009-06-23 06:03:08 +0000309 return NETDEV_TX_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700311
312 switch (skb->data[0]) {
andrew hendry7eeeacf02010-04-19 13:29:47 +0000313 case X25_IFACE_DATA:
Alan Coxf34d7a52008-04-30 00:54:13 -0700314 break;
andrew hendry7eeeacf02010-04-19 13:29:47 +0000315 case X25_IFACE_CONNECT: /* Connection request .. do nothing */
Alan Coxf34d7a52008-04-30 00:54:13 -0700316 err = lapb_connect_request(dev);
317 if (err != LAPB_OK)
Joe Perches23efcb72011-06-26 19:01:35 +0000318 netdev_err(dev, "lapb_connect_request error: %d\n",
319 err);
Alan Coxf34d7a52008-04-30 00:54:13 -0700320 kfree_skb(skb);
Patrick McHardy6ed10652009-06-23 06:03:08 +0000321 return NETDEV_TX_OK;
andrew hendry7eeeacf02010-04-19 13:29:47 +0000322 case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
Alan Coxf34d7a52008-04-30 00:54:13 -0700323 err = lapb_disconnect_request(dev);
324 if (err != LAPB_OK)
Joe Perches23efcb72011-06-26 19:01:35 +0000325 netdev_err(dev, "lapb_disconnect_request error: %d\n",
326 err);
Gustavo A. R. Silvaa3e2ecb2017-11-08 22:25:08 -0600327 /* fall through */
Alan Coxf34d7a52008-04-30 00:54:13 -0700328 default:
329 kfree_skb(skb);
Patrick McHardy6ed10652009-06-23 06:03:08 +0000330 return NETDEV_TX_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700332 skb_pull(skb, 1); /* Remove control byte */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 /*
334 * If we are busy already- too bad. We ought to be able
335 * to queue things at this point, to allow for a little
336 * frame buffer. Oh well...
337 * -----------------------------------------------------
338 * I hate queues in X.25 driver. May be it's efficient,
339 * but for me latency is more important. ;)
340 * So, no queues !
341 * 14 Oct 1994 Dmitry Gorodchanin.
342 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700343
344 err = lapb_data_request(dev, skb);
345 if (err != LAPB_OK) {
Joe Perches23efcb72011-06-26 19:01:35 +0000346 netdev_err(dev, "lapb_data_request error: %d\n", err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 kfree_skb(skb);
Patrick McHardy6ed10652009-06-23 06:03:08 +0000348 return NETDEV_TX_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 }
Patrick McHardy6ed10652009-06-23 06:03:08 +0000350 return NETDEV_TX_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351}
352
353
354/*
355 * LAPB interface boilerplate
356 */
357
358/*
359 * Called when I frame data arrives. We did the work above - throw it
360 * at the net layer.
361 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700362
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
364{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 return netif_rx(skb);
366}
367
368/*
369 * Data has emerged from the LAPB protocol machine. We don't handle
370 * busy cases too well. Its tricky to see how to do this nicely -
371 * perhaps lapb should allow us to bounce this ?
372 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700373
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
375{
Wang Chen8f15ea42008-11-12 23:38:36 -0800376 struct x25_asy *sl = netdev_priv(dev);
Alan Coxf34d7a52008-04-30 00:54:13 -0700377
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 spin_lock(&sl->lock);
Alan Coxf34d7a52008-04-30 00:54:13 -0700379 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 spin_unlock(&sl->lock);
Joe Perches23efcb72011-06-26 19:01:35 +0000381 netdev_err(dev, "tbusy drop\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 kfree_skb(skb);
383 return;
384 }
385 /* We were not busy, so we are now... :-) */
Alan Coxf34d7a52008-04-30 00:54:13 -0700386 if (skb != NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 x25_asy_lock(sl);
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000388 dev->stats.tx_bytes += skb->len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 x25_asy_encaps(sl, skb->data, skb->len);
390 dev_kfree_skb(skb);
391 }
392 spin_unlock(&sl->lock);
393}
394
395/*
396 * LAPB connection establish/down information.
397 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700398
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399static void x25_asy_connected(struct net_device *dev, int reason)
400{
Wang Chen8f15ea42008-11-12 23:38:36 -0800401 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 struct sk_buff *skb;
403 unsigned char *ptr;
404
Alan Coxf34d7a52008-04-30 00:54:13 -0700405 skb = dev_alloc_skb(1);
406 if (skb == NULL) {
Joe Perches23efcb72011-06-26 19:01:35 +0000407 netdev_err(dev, "out of memory\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 return;
409 }
410
411 ptr = skb_put(skb, 1);
andrew hendry7eeeacf02010-04-19 13:29:47 +0000412 *ptr = X25_IFACE_CONNECT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413
414 skb->protocol = x25_type_trans(skb, sl->dev);
415 netif_rx(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416}
417
418static void x25_asy_disconnected(struct net_device *dev, int reason)
419{
Wang Chen8f15ea42008-11-12 23:38:36 -0800420 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 struct sk_buff *skb;
422 unsigned char *ptr;
423
Alan Coxf34d7a52008-04-30 00:54:13 -0700424 skb = dev_alloc_skb(1);
425 if (skb == NULL) {
Joe Perches23efcb72011-06-26 19:01:35 +0000426 netdev_err(dev, "out of memory\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 return;
428 }
429
430 ptr = skb_put(skb, 1);
andrew hendry7eeeacf02010-04-19 13:29:47 +0000431 *ptr = X25_IFACE_DISCONNECT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432
433 skb->protocol = x25_type_trans(skb, sl->dev);
434 netif_rx(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435}
436
stephen hemmingerd97a0772011-09-16 11:04:29 +0000437static const struct lapb_register_struct x25_asy_callbacks = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 .connect_confirmation = x25_asy_connected,
439 .connect_indication = x25_asy_connected,
440 .disconnect_confirmation = x25_asy_disconnected,
441 .disconnect_indication = x25_asy_disconnected,
442 .data_indication = x25_asy_data_indication,
443 .data_transmit = x25_asy_data_transmit,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444};
445
446
447/* Open the low-level part of the X.25 channel. Easy! */
448static int x25_asy_open(struct net_device *dev)
449{
Wang Chen8f15ea42008-11-12 23:38:36 -0800450 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 unsigned long len;
452 int err;
453
454 if (sl->tty == NULL)
455 return -ENODEV;
456
457 /*
458 * Allocate the X.25 frame buffers:
459 *
460 * rbuff Receive buffer.
461 * xbuff Transmit buffer.
462 */
463
464 len = dev->mtu * 2;
465
Robert P. J. Day5cbded52006-12-13 00:35:56 -0800466 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
Alan Coxf34d7a52008-04-30 00:54:13 -0700467 if (sl->rbuff == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 goto norbuff;
Robert P. J. Day5cbded52006-12-13 00:35:56 -0800469 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
Alan Coxf34d7a52008-04-30 00:54:13 -0700470 if (sl->xbuff == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 goto noxbuff;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472
473 sl->buffsize = len;
474 sl->rcount = 0;
475 sl->xleft = 0;
476 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
477
478 netif_start_queue(dev);
Alan Coxf34d7a52008-04-30 00:54:13 -0700479
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 /*
481 * Now attach LAPB
482 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700483 err = lapb_register(dev, &x25_asy_callbacks);
484 if (err == LAPB_OK)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 return 0;
486
487 /* Cleanup */
488 kfree(sl->xbuff);
Cong Wangd5c7c742018-12-29 13:56:37 -0800489 sl->xbuff = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490noxbuff:
491 kfree(sl->rbuff);
Cong Wangd5c7c742018-12-29 13:56:37 -0800492 sl->rbuff = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493norbuff:
494 return -ENOMEM;
495}
496
497
498/* Close the low-level part of the X.25 channel. Easy! */
499static int x25_asy_close(struct net_device *dev)
500{
Wang Chen8f15ea42008-11-12 23:38:36 -0800501 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502
503 spin_lock(&sl->lock);
Alan Coxf34d7a52008-04-30 00:54:13 -0700504 if (sl->tty)
Alan Cox8a1ec212008-12-05 22:31:52 -0800505 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506
507 netif_stop_queue(dev);
508 sl->rcount = 0;
509 sl->xleft = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 spin_unlock(&sl->lock);
511 return 0;
512}
513
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514/*
515 * Handle the 'receiver data ready' interrupt.
516 * This function is called by the 'tty_io' module in the kernel when
517 * a block of X.25 data has been received, which can now be decapsulated
518 * and sent on to some IP layer for further processing.
519 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700520
521static void x25_asy_receive_buf(struct tty_struct *tty,
522 const unsigned char *cp, char *fp, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523{
Alan Coxd2b88812008-12-05 22:32:22 -0800524 struct x25_asy *sl = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525
526 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
527 return;
528
529
530 /* Read the characters out of the buffer */
531 while (count--) {
532 if (fp && *fp++) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700533 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000534 sl->dev->stats.rx_errors++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 cp++;
536 continue;
537 }
538 x25_asy_unesc(sl, *cp++);
539 }
540}
541
542/*
543 * Open the high-level part of the X.25 channel.
544 * This function is called by the TTY module when the
545 * X.25 line discipline is called for. Because we are
546 * sure the tty line exists, we only have to link it to
547 * a free X.25 channel...
548 */
549
550static int x25_asy_open_tty(struct tty_struct *tty)
551{
Peter Hurleyee9159d2015-11-27 14:18:39 -0500552 struct x25_asy *sl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 int err;
554
Alan Coxf34d7a52008-04-30 00:54:13 -0700555 if (tty->ops->write == NULL)
556 return -EOPNOTSUPP;
557
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 /* OK. Find a free X.25 channel to use. */
Alan Coxf34d7a52008-04-30 00:54:13 -0700559 sl = x25_asy_alloc();
560 if (sl == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 return -ENFILE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562
563 sl->tty = tty;
564 tty->disc_data = sl;
Alan Cox33f0f882006-01-09 20:54:13 -0800565 tty->receive_room = 65536;
Alan Coxf34d7a52008-04-30 00:54:13 -0700566 tty_driver_flush_buffer(tty);
Alan Cox11b0cc32008-02-08 15:00:48 -0800567 tty_ldisc_flush(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568
569 /* Restore default settings */
570 sl->dev->type = ARPHRD_X25;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571
Alan Coxf34d7a52008-04-30 00:54:13 -0700572 /* Perform the low-level X.25 async init */
573 err = x25_asy_open(sl->dev);
David S. Miller3b780be2016-01-13 11:45:39 -0500574 if (err) {
575 x25_asy_free(sl);
Alan Coxf34d7a52008-04-30 00:54:13 -0700576 return err;
David S. Miller3b780be2016-01-13 11:45:39 -0500577 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 /* Done. We have linked the TTY line to a channel. */
Jiri Slaby6a20bd42010-11-25 00:27:55 +0100579 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580}
581
582
583/*
584 * Close down an X.25 channel.
585 * This means flushing out any pending queues, and then restoring the
586 * TTY line discipline to what it was before it got hooked to X.25
587 * (which usually is TTY again).
588 */
589static void x25_asy_close_tty(struct tty_struct *tty)
590{
Alan Coxd2b88812008-12-05 22:32:22 -0800591 struct x25_asy *sl = tty->disc_data;
Jiri Slaby03fe5f32010-11-24 13:54:54 +0000592 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
594 /* First make sure we're connected. */
595 if (!sl || sl->magic != X25_ASY_MAGIC)
596 return;
597
Ben Hutchings3e3cda92008-05-06 19:41:48 +0100598 rtnl_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 if (sl->dev->flags & IFF_UP)
Alan Coxf34d7a52008-04-30 00:54:13 -0700600 dev_close(sl->dev);
Ben Hutchings3e3cda92008-05-06 19:41:48 +0100601 rtnl_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602
Jiri Slaby03fe5f32010-11-24 13:54:54 +0000603 err = lapb_unregister(sl->dev);
604 if (err != LAPB_OK)
Jeremy Sowden8e6a4812019-06-16 11:43:32 +0100605 pr_err("%s: lapb_unregister error: %d\n",
606 __func__, err);
Jiri Slaby03fe5f32010-11-24 13:54:54 +0000607
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 tty->disc_data = NULL;
609 sl->tty = NULL;
610 x25_asy_free(sl);
611}
612
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 /************************************************************************
614 * STANDARD X.25 ENCAPSULATION *
615 ************************************************************************/
616
Hannes Eder7b3dfa12008-12-26 00:11:21 -0800617static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618{
619 unsigned char *ptr = d;
620 unsigned char c;
621
622 /*
623 * Send an initial END character to flush out any
624 * data that may have accumulated in the receiver
625 * due to line noise.
626 */
627
628 *ptr++ = X25_END; /* Send 10111110 bit seq */
629
630 /*
631 * For each byte in the packet, send the appropriate
632 * character sequence, according to the X.25 protocol.
633 */
634
Alan Coxf34d7a52008-04-30 00:54:13 -0700635 while (len-- > 0) {
636 switch (c = *s++) {
637 case X25_END:
638 *ptr++ = X25_ESC;
639 *ptr++ = X25_ESCAPE(X25_END);
640 break;
641 case X25_ESC:
642 *ptr++ = X25_ESC;
643 *ptr++ = X25_ESCAPE(X25_ESC);
644 break;
645 default:
646 *ptr++ = c;
647 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 }
649 }
650 *ptr++ = X25_END;
Eric Dumazet807540b2010-09-23 05:40:09 +0000651 return ptr - d;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652}
653
654static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
655{
656
Alan Coxf34d7a52008-04-30 00:54:13 -0700657 switch (s) {
658 case X25_END:
Joe Perches8e95a202009-12-03 07:58:21 +0000659 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
660 sl->rcount > 2)
Alan Coxf34d7a52008-04-30 00:54:13 -0700661 x25_asy_bump(sl);
662 clear_bit(SLF_ESCAPE, &sl->flags);
663 sl->rcount = 0;
664 return;
665 case X25_ESC:
666 set_bit(SLF_ESCAPE, &sl->flags);
667 return;
668 case X25_ESCAPE(X25_ESC):
669 case X25_ESCAPE(X25_END):
670 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
671 s = X25_UNESCAPE(s);
672 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700674 if (!test_bit(SLF_ERROR, &sl->flags)) {
675 if (sl->rcount < sl->buffsize) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 sl->rbuff[sl->rcount++] = s;
677 return;
678 }
Stephen Hemminger6a8eba32009-03-20 19:36:12 +0000679 sl->dev->stats.rx_over_errors++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 set_bit(SLF_ERROR, &sl->flags);
681 }
682}
683
684
685/* Perform I/O control on an active X.25 channel. */
686static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
687 unsigned int cmd, unsigned long arg)
688{
Alan Coxd2b88812008-12-05 22:32:22 -0800689 struct x25_asy *sl = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690
691 /* First make sure we're connected. */
692 if (!sl || sl->magic != X25_ASY_MAGIC)
693 return -EINVAL;
694
Alan Coxf34d7a52008-04-30 00:54:13 -0700695 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 case SIOCGIFNAME:
697 if (copy_to_user((void __user *)arg, sl->dev->name,
698 strlen(sl->dev->name) + 1))
699 return -EFAULT;
700 return 0;
701 case SIOCSIFHWADDR:
702 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 default:
Alan Coxd0127532007-11-07 01:27:34 -0800704 return tty_mode_ioctl(tty, file, cmd, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 }
706}
707
708static int x25_asy_open_dev(struct net_device *dev)
709{
Wang Chen8f15ea42008-11-12 23:38:36 -0800710 struct x25_asy *sl = netdev_priv(dev);
Alan Coxf34d7a52008-04-30 00:54:13 -0700711 if (sl->tty == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 return -ENODEV;
713 return 0;
714}
715
Stephen Hemminger48f26ad2009-03-20 19:36:13 +0000716static const struct net_device_ops x25_asy_netdev_ops = {
717 .ndo_open = x25_asy_open_dev,
718 .ndo_stop = x25_asy_close,
719 .ndo_start_xmit = x25_asy_xmit,
720 .ndo_tx_timeout = x25_asy_timeout,
721 .ndo_change_mtu = x25_asy_change_mtu,
722};
723
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724/* Initialise the X.25 driver. Called by the device init code */
725static void x25_asy_setup(struct net_device *dev)
726{
Wang Chen8f15ea42008-11-12 23:38:36 -0800727 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728
729 sl->magic = X25_ASY_MAGIC;
730 sl->dev = dev;
731 spin_lock_init(&sl->lock);
732 set_bit(SLF_INUSE, &sl->flags);
733
734 /*
Alan Coxf34d7a52008-04-30 00:54:13 -0700735 * Finish setting up the DEVICE info.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700737
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 dev->mtu = SL_MTU;
Jarod Wilson8b6b4132016-10-20 13:55:19 -0400739 dev->min_mtu = 0;
740 dev->max_mtu = 65534;
Stephen Hemminger48f26ad2009-03-20 19:36:13 +0000741 dev->netdev_ops = &x25_asy_netdev_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 dev->watchdog_timeo = HZ*20;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 dev->hard_header_len = 0;
744 dev->addr_len = 0;
745 dev->type = ARPHRD_X25;
746 dev->tx_queue_len = 10;
747
748 /* New-style flags. */
749 dev->flags = IFF_NOARP;
750}
751
Alan Coxa352def2008-07-16 21:53:12 +0100752static struct tty_ldisc_ops x25_ldisc = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 .owner = THIS_MODULE,
754 .magic = TTY_LDISC_MAGIC,
755 .name = "X.25",
756 .open = x25_asy_open_tty,
757 .close = x25_asy_close_tty,
758 .ioctl = x25_asy_ioctl,
759 .receive_buf = x25_asy_receive_buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 .write_wakeup = x25_asy_write_wakeup,
761};
762
763static int __init init_x25_asy(void)
764{
765 if (x25_asy_maxdev < 4)
766 x25_asy_maxdev = 4; /* Sanity */
767
Joe Perches23efcb72011-06-26 19:01:35 +0000768 pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n",
769 x25_asy_maxdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770
Alan Coxf34d7a52008-04-30 00:54:13 -0700771 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
772 GFP_KERNEL);
Joe Perchese404dec2012-01-29 12:56:23 +0000773 if (!x25_asy_devs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
776 return tty_register_ldisc(N_X25, &x25_ldisc);
777}
778
779
780static void __exit exit_x25_asy(void)
781{
782 struct net_device *dev;
783 int i;
784
785 for (i = 0; i < x25_asy_maxdev; i++) {
786 dev = x25_asy_devs[i];
787 if (dev) {
Wang Chen8f15ea42008-11-12 23:38:36 -0800788 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789
790 spin_lock_bh(&sl->lock);
Alan Coxf34d7a52008-04-30 00:54:13 -0700791 if (sl->tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 tty_hangup(sl->tty);
793
794 spin_unlock_bh(&sl->lock);
795 /*
796 * VSV = if dev->start==0, then device
797 * unregistered while close proc.
798 */
799 unregister_netdev(dev);
800 free_netdev(dev);
801 }
802 }
803
804 kfree(x25_asy_devs);
Alexey Dobriyan64ccd712005-06-23 00:10:33 -0700805 tty_unregister_ldisc(N_X25);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806}
807
808module_init(init_x25_asy);
809module_exit(exit_x25_asy);