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