xref: /kernel/linux/linux-5.10/drivers/net/wan/dlci.c (revision 8c2ecf20) 
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");
542