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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * DLCI Implementation of Frame Relay protocol for Linux, according to
4 * RFC 1490. This generic device provides en/decapsulation for an
5 * underlying hardware driver. Routes & IPs are assigned to these
6 * interfaces. Requires 'dlcicfg' program to create usable
7 * interfaces, the initial one, 'dlci' is for IOCTL use only.
8 *
9 * Version: @(#)dlci.c 0.35 4 Jan 1997
10 *
11 * Author: Mike McLagan <mike.mclagan@linux.org>
12 *
13 * Changes:
14 *
15 * 0.15 Mike Mclagan Packet freeing, bug in kmalloc call
16 * DLCI_RET handling
17 * 0.20 Mike McLagan More conservative on which packets
18 * are returned for retry and which are
19 * are dropped. If DLCI_RET_DROP is
20 * returned from the FRAD, the packet is
21 * sent back to Linux for re-transmission
22 * 0.25 Mike McLagan Converted to use SIOC IOCTL calls
23 * 0.30 Jim Freeman Fixed to allow IPX traffic
24 * 0.35 Michael Elizabeth Fixed incorrect memcpy_fromfs
25 */
26
27#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
29#include <linux/module.h>
30#include <linux/kernel.h>
31#include <linux/types.h>
32#include <linux/fcntl.h>
33#include <linux/interrupt.h>
34#include <linux/ptrace.h>
35#include <linux/ioport.h>
36#include <linux/in.h>
37#include <linux/init.h>
38#include <linux/slab.h>
39#include <linux/string.h>
40#include <linux/errno.h>
41#include <linux/netdevice.h>
42#include <linux/skbuff.h>
43#include <linux/if_arp.h>
44#include <linux/if_frad.h>
45#include <linux/bitops.h>
46
47#include <net/sock.h>
48
49#include <asm/io.h>
50#include <asm/dma.h>
51#include <linux/uaccess.h>
52
53static const char version[] = "DLCI driver v0.35, 4 Jan 1997, mike.mclagan@linux.org";
54
55static LIST_HEAD(dlci_devs);
56
57static void dlci_setup(struct net_device *);
58
59/*
60 * these encapsulate the RFC 1490 requirements as well as
61 * deal with packet transmission and reception, working with
62 * the upper network layers
63 */
64
65static int dlci_header(struct sk_buff *skb, struct net_device *dev,
66 unsigned short type, const void *daddr,
67 const void *saddr, unsigned len)
68{
69 struct frhdr hdr;
70 unsigned int hlen;
71 char *dest;
72
73 hdr.control = FRAD_I_UI;
74 switch (type)
75 {
76 case ETH_P_IP:
77 hdr.IP_NLPID = FRAD_P_IP;
78 hlen = sizeof(hdr.control) + sizeof(hdr.IP_NLPID);
79 break;
80
81 /* feel free to add other types, if necessary */
82
83 default:
84 hdr.pad = FRAD_P_PADDING;
85 hdr.NLPID = FRAD_P_SNAP;
86 memset(hdr.OUI, 0, sizeof(hdr.OUI));
87 hdr.PID = htons(type);
88 hlen = sizeof(hdr);
89 break;
90 }
91
92 dest = skb_push(skb, hlen);
93 if (!dest)
94 return 0;
95
96 memcpy(dest, &hdr, hlen);
97
98 return hlen;
99}
100
101static void dlci_receive(struct sk_buff *skb, struct net_device *dev)
102{
103 struct frhdr *hdr;
104 int process, header;
105
106 if (!pskb_may_pull(skb, sizeof(*hdr))) {
107 netdev_notice(dev, "invalid data no header\n");
108 dev->stats.rx_errors++;
109 kfree_skb(skb);
110 return;
111 }
112
113 hdr = (struct frhdr *) skb->data;
114 process = 0;
115 header = 0;
116 skb->dev = dev;
117
118 if (hdr->control != FRAD_I_UI)
119 {
120 netdev_notice(dev, "Invalid header flag 0x%02X\n",
121 hdr->control);
122 dev->stats.rx_errors++;
123 }
124 else
125 switch (hdr->IP_NLPID)
126 {
127 case FRAD_P_PADDING:
128 if (hdr->NLPID != FRAD_P_SNAP)
129 {
130 netdev_notice(dev, "Unsupported NLPID 0x%02X\n",
131 hdr->NLPID);
132 dev->stats.rx_errors++;
133 break;
134 }
135
136 if (hdr->OUI[0] + hdr->OUI[1] + hdr->OUI[2] != 0)
137 {
138 netdev_notice(dev, "Unsupported organizationally unique identifier 0x%02X-%02X-%02X\n",
139 hdr->OUI[0],
140 hdr->OUI[1],
141 hdr->OUI[2]);
142 dev->stats.rx_errors++;
143 break;
144 }
145
146 /* at this point, it's an EtherType frame */
147 header = sizeof(struct frhdr);
148 /* Already in network order ! */
149 skb->protocol = hdr->PID;
150 process = 1;
151 break;
152
153 case FRAD_P_IP:
154 header = sizeof(hdr->control) + sizeof(hdr->IP_NLPID);
155 skb->protocol = htons(ETH_P_IP);
156 process = 1;
157 break;
158
159 case FRAD_P_SNAP:
160 case FRAD_P_Q933:
161 case FRAD_P_CLNP:
162 netdev_notice(dev, "Unsupported NLPID 0x%02X\n",
163 hdr->pad);
164 dev->stats.rx_errors++;
165 break;
166
167 default:
168 netdev_notice(dev, "Invalid pad byte 0x%02X\n",
169 hdr->pad);
170 dev->stats.rx_errors++;
171 break;
172 }
173
174 if (process)
175 {
176 /* we've set up the protocol, so discard the header */
177 skb_reset_mac_header(skb);
178 skb_pull(skb, header);
179 dev->stats.rx_bytes += skb->len;
180 netif_rx(skb);
181 dev->stats.rx_packets++;
182 }
183 else
184 dev_kfree_skb(skb);
185}
186
187static netdev_tx_t dlci_transmit(struct sk_buff *skb, struct net_device *dev)
188{
189 struct dlci_local *dlp = netdev_priv(dev);
190
191 if (skb) {
192 struct netdev_queue *txq = skb_get_tx_queue(dev, skb);
193 netdev_start_xmit(skb, dlp->slave, txq, false);
194 }
195 return NETDEV_TX_OK;
196}
197
198static int dlci_config(struct net_device *dev, struct dlci_conf __user *conf, int get)
199{
200 struct dlci_conf config;
201 struct dlci_local *dlp;
202 struct frad_local *flp;
203 int err;
204
205 dlp = netdev_priv(dev);
206
207 flp = netdev_priv(dlp->slave);
208
209 if (!get)
210 {
211 if (copy_from_user(&config, conf, sizeof(struct dlci_conf)))
212 return -EFAULT;
213 if (config.flags & ~DLCI_VALID_FLAGS)
214 return -EINVAL;
215 memcpy(&dlp->config, &config, sizeof(struct dlci_conf));
216 dlp->configured = 1;
217 }
218
219 err = (*flp->dlci_conf)(dlp->slave, dev, get);
220 if (err)
221 return err;
222
223 if (get)
224 {
225 if (copy_to_user(conf, &dlp->config, sizeof(struct dlci_conf)))
226 return -EFAULT;
227 }
228
229 return 0;
230}
231
232static int dlci_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
233{
234 struct dlci_local *dlp;
235
236 if (!capable(CAP_NET_ADMIN))
237 return -EPERM;
238
239 dlp = netdev_priv(dev);
240
241 switch (cmd)
242 {
243 case DLCI_GET_SLAVE:
244 if (!*(short *)(dev->dev_addr))
245 return -EINVAL;
246
247 strncpy(ifr->ifr_slave, dlp->slave->name, sizeof(ifr->ifr_slave));
248 break;
249
250 case DLCI_GET_CONF:
251 case DLCI_SET_CONF:
252 if (!*(short *)(dev->dev_addr))
253 return -EINVAL;
254
255 return dlci_config(dev, ifr->ifr_data, cmd == DLCI_GET_CONF);
256
257 default:
258 return -EOPNOTSUPP;
259 }
260 return 0;
261}
262
263static int dlci_change_mtu(struct net_device *dev, int new_mtu)
264{
265 struct dlci_local *dlp = netdev_priv(dev);
266
267 return dev_set_mtu(dlp->slave, new_mtu);
268}
269
270static int dlci_open(struct net_device *dev)
271{
272 struct dlci_local *dlp;
273 struct frad_local *flp;
274 int err;
275
276 dlp = netdev_priv(dev);
277
278 if (!*(short *)(dev->dev_addr))
279 return -EINVAL;
280
281 if (!netif_running(dlp->slave))
282 return -ENOTCONN;
283
284 flp = netdev_priv(dlp->slave);
285 err = (*flp->activate)(dlp->slave, dev);
286 if (err)
287 return err;
288
289 netif_start_queue(dev);
290
291 return 0;
292}
293
294static int dlci_close(struct net_device *dev)
295{
296 struct dlci_local *dlp;
297 struct frad_local *flp;
298
299 netif_stop_queue(dev);
300
301 dlp = netdev_priv(dev);
302
303 flp = netdev_priv(dlp->slave);
304 (*flp->deactivate)(dlp->slave, dev);
305
306 return 0;
307}
308
309static int dlci_add(struct dlci_add *dlci)
310{
311 struct net_device *master, *slave;
312 struct dlci_local *dlp;
313 struct frad_local *flp;
314 int err = -EINVAL;
315
316
317 /* validate slave device */
318 slave = dev_get_by_name(&init_net, dlci->devname);
319 if (!slave)
320 return -ENODEV;
321
322 if (slave->type != ARPHRD_FRAD || netdev_priv(slave) == NULL)
323 goto err1;
324
325 /* create device name */
326 master = alloc_netdev(sizeof(struct dlci_local), "dlci%d",
327 NET_NAME_UNKNOWN, dlci_setup);
328 if (!master) {
329 err = -ENOMEM;
330 goto err1;
331 }
332
333 /* make sure same slave not already registered */
334 rtnl_lock();
335 list_for_each_entry(dlp, &dlci_devs, list) {
336 if (dlp->slave == slave) {
337 err = -EBUSY;
338 goto err2;
339 }
340 }
341
342 *(short *)(master->dev_addr) = dlci->dlci;
343
344 dlp = netdev_priv(master);
345 dlp->slave = slave;
346 dlp->master = master;
347
348 flp = netdev_priv(slave);
349 err = (*flp->assoc)(slave, master);
350 if (err < 0)
351 goto err2;
352
353 err = register_netdevice(master);
354 if (err < 0)
355 goto err2;
356
357 strcpy(dlci->devname, master->name);
358
359 list_add(&dlp->list, &dlci_devs);
360 rtnl_unlock();
361
362 return 0;
363
364 err2:
365 rtnl_unlock();
366 free_netdev(master);
367 err1:
368 dev_put(slave);
369 return err;
370}
371
372static int dlci_del(struct dlci_add *dlci)
373{
374 struct dlci_local *dlp;
375 struct frad_local *flp;
376 struct net_device *master, *slave;
377 int err;
378 bool found = false;
379
380 rtnl_lock();
381
382 /* validate slave device */
383 master = __dev_get_by_name(&init_net, dlci->devname);
384 if (!master) {
385 err = -ENODEV;
386 goto out;
387 }
388
389 list_for_each_entry(dlp, &dlci_devs, list) {
390 if (dlp->master == master) {
391 found = true;
392 break;
393 }
394 }
395 if (!found) {
396 err = -ENODEV;
397 goto out;
398 }
399
400 if (netif_running(master)) {
401 err = -EBUSY;
402 goto out;
403 }
404
405 dlp = netdev_priv(master);
406 slave = dlp->slave;
407 flp = netdev_priv(slave);
408
409 err = (*flp->deassoc)(slave, master);
410 if (!err) {
411 list_del(&dlp->list);
412
413 unregister_netdevice(master);
414
415 dev_put(slave);
416 }
417out:
418 rtnl_unlock();
419 return err;
420}
421
422static int dlci_ioctl(unsigned int cmd, void __user *arg)
423{
424 struct dlci_add add;
425 int err;
426
427 if (!capable(CAP_NET_ADMIN))
428 return -EPERM;
429
430 if (copy_from_user(&add, arg, sizeof(struct dlci_add)))
431 return -EFAULT;
432
433 switch (cmd)
434 {
435 case SIOCADDDLCI:
436 err = dlci_add(&add);
437
438 if (!err)
439 if (copy_to_user(arg, &add, sizeof(struct dlci_add)))
440 return -EFAULT;
441 break;
442
443 case SIOCDELDLCI:
444 err = dlci_del(&add);
445 break;
446
447 default:
448 err = -EINVAL;
449 }
450
451 return err;
452}
453
454static const struct header_ops dlci_header_ops = {
455 .create = dlci_header,
456};
457
458static const struct net_device_ops dlci_netdev_ops = {
459 .ndo_open = dlci_open,
460 .ndo_stop = dlci_close,
461 .ndo_do_ioctl = dlci_dev_ioctl,
462 .ndo_start_xmit = dlci_transmit,
463 .ndo_change_mtu = dlci_change_mtu,
464};
465
466static void dlci_setup(struct net_device *dev)
467{
468 struct dlci_local *dlp = netdev_priv(dev);
469
470 dev->flags = 0;
471 dev->header_ops = &dlci_header_ops;
472 dev->netdev_ops = &dlci_netdev_ops;
473 dev->needs_free_netdev = true;
474
475 dlp->receive = dlci_receive;
476
477 dev->type = ARPHRD_DLCI;
478 dev->hard_header_len = sizeof(struct frhdr);
479 dev->addr_len = sizeof(short);
480
481}
482
483/* if slave is unregistering, then cleanup master */
484static int dlci_dev_event(struct notifier_block *unused,
485 unsigned long event, void *ptr)
486{
487 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
488
489 if (dev_net(dev) != &init_net)
490 return NOTIFY_DONE;
491
492 if (event == NETDEV_UNREGISTER) {
493 struct dlci_local *dlp;
494
495 list_for_each_entry(dlp, &dlci_devs, list) {
496 if (dlp->slave == dev) {
497 list_del(&dlp->list);
498 unregister_netdevice(dlp->master);
499 dev_put(dlp->slave);
500 break;
501 }
502 }
503 }
504 return NOTIFY_DONE;
505}
506
507static struct notifier_block dlci_notifier = {
508 .notifier_call = dlci_dev_event,
509};
510
511static int __init init_dlci(void)
512{
513 dlci_ioctl_set(dlci_ioctl);
514 register_netdevice_notifier(&dlci_notifier);
515
516 printk("%s.\n", version);
517
518 return 0;
519}
520
521static void __exit dlci_exit(void)
522{
523 struct dlci_local *dlp, *nxt;
524
525 dlci_ioctl_set(NULL);
526 unregister_netdevice_notifier(&dlci_notifier);
527
528 rtnl_lock();
529 list_for_each_entry_safe(dlp, nxt, &dlci_devs, list) {
530 unregister_netdevice(dlp->master);
531 dev_put(dlp->slave);
532 }
533 rtnl_unlock();
534}
535
536module_init(init_dlci);
537module_exit(dlci_exit);
538
539MODULE_AUTHOR("Mike McLagan");
540MODULE_DESCRIPTION("Frame Relay DLCI layer");
541MODULE_LICENSE("GPL");