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/io.h>
54#include <asm/dma.h>
55#include <asm/uaccess.h>
56
57static const char version[] = "DLCI driver v0.35, 4 Jan 1997, mike.mclagan@linux.org";
58
59static LIST_HEAD(dlci_devs);
60
61static void dlci_setup(struct net_device *);
62
63/*
64 * these encapsulate the RFC 1490 requirements as well as
65 * deal with packet transmission and reception, working with
66 * the upper network layers
67 */
68
69static int dlci_header(struct sk_buff *skb, struct net_device *dev,
70		       unsigned short type, const void *daddr,
71		       const void *saddr, unsigned len)
72{
73	struct frhdr		hdr;
74	unsigned int		hlen;
75	char			*dest;
76
77	hdr.control = FRAD_I_UI;
78	switch (type)
79	{
80		case ETH_P_IP:
81			hdr.IP_NLPID = FRAD_P_IP;
82			hlen = sizeof(hdr.control) + sizeof(hdr.IP_NLPID);
83			break;
84
85		/* feel free to add other types, if necessary */
86
87		default:
88			hdr.pad = FRAD_P_PADDING;
89			hdr.NLPID = FRAD_P_SNAP;
90			memset(hdr.OUI, 0, sizeof(hdr.OUI));
91			hdr.PID = htons(type);
92			hlen = sizeof(hdr);
93			break;
94	}
95
96	dest = skb_push(skb, hlen);
97	if (!dest)
98		return 0;
99
100	memcpy(dest, &hdr, hlen);
101
102	return hlen;
103}
104
105static void dlci_receive(struct sk_buff *skb, struct net_device *dev)
106{
107	struct frhdr		*hdr;
108	int					process, header;
109
110	if (!pskb_may_pull(skb, sizeof(*hdr))) {
111		netdev_notice(dev, "invalid data no header\n");
112		dev->stats.rx_errors++;
113		kfree_skb(skb);
114		return;
115	}
116
117	hdr = (struct frhdr *) skb->data;
118	process = 0;
119	header = 0;
120	skb->dev = dev;
121
122	if (hdr->control != FRAD_I_UI)
123	{
124		netdev_notice(dev, "Invalid header flag 0x%02X\n",
125			      hdr->control);
126		dev->stats.rx_errors++;
127	}
128	else
129		switch (hdr->IP_NLPID)
130		{
131			case FRAD_P_PADDING:
132				if (hdr->NLPID != FRAD_P_SNAP)
133				{
134					netdev_notice(dev, "Unsupported NLPID 0x%02X\n",
135						      hdr->NLPID);
136					dev->stats.rx_errors++;
137					break;
138				}
139
140				if (hdr->OUI[0] + hdr->OUI[1] + hdr->OUI[2] != 0)
141				{
142					netdev_notice(dev, "Unsupported organizationally unique identifier 0x%02X-%02X-%02X\n",
143						      hdr->OUI[0],
144						      hdr->OUI[1],
145						      hdr->OUI[2]);
146					dev->stats.rx_errors++;
147					break;
148				}
149
150				/* at this point, it's an EtherType frame */
151				header = sizeof(struct frhdr);
152				/* Already in network order ! */
153				skb->protocol = hdr->PID;
154				process = 1;
155				break;
156
157			case FRAD_P_IP:
158				header = sizeof(hdr->control) + sizeof(hdr->IP_NLPID);
159				skb->protocol = htons(ETH_P_IP);
160				process = 1;
161				break;
162
163			case FRAD_P_SNAP:
164			case FRAD_P_Q933:
165			case FRAD_P_CLNP:
166				netdev_notice(dev, "Unsupported NLPID 0x%02X\n",
167					      hdr->pad);
168				dev->stats.rx_errors++;
169				break;
170
171			default:
172				netdev_notice(dev, "Invalid pad byte 0x%02X\n",
173					      hdr->pad);
174				dev->stats.rx_errors++;
175				break;
176		}
177
178	if (process)
179	{
180		/* we've set up the protocol, so discard the header */
181		skb_reset_mac_header(skb);
182		skb_pull(skb, header);
183		dev->stats.rx_bytes += skb->len;
184		netif_rx(skb);
185		dev->stats.rx_packets++;
186	}
187	else
188		dev_kfree_skb(skb);
189}
190
191static netdev_tx_t dlci_transmit(struct sk_buff *skb, struct net_device *dev)
192{
193	struct dlci_local *dlp = netdev_priv(dev);
194
195	if (skb) {
196		struct netdev_queue *txq = skb_get_tx_queue(dev, skb);
197		netdev_start_xmit(skb, dlp->slave, txq, false);
198	}
199	return NETDEV_TX_OK;
200}
201
202static int dlci_config(struct net_device *dev, struct dlci_conf __user *conf, int get)
203{
204	struct dlci_conf	config;
205	struct dlci_local	*dlp;
206	struct frad_local	*flp;
207	int			err;
208
209	dlp = netdev_priv(dev);
210
211	flp = netdev_priv(dlp->slave);
212
213	if (!get)
214	{
215		if (copy_from_user(&config, conf, sizeof(struct dlci_conf)))
216			return -EFAULT;
217		if (config.flags & ~DLCI_VALID_FLAGS)
218			return -EINVAL;
219		memcpy(&dlp->config, &config, sizeof(struct dlci_conf));
220		dlp->configured = 1;
221	}
222
223	err = (*flp->dlci_conf)(dlp->slave, dev, get);
224	if (err)
225		return err;
226
227	if (get)
228	{
229		if (copy_to_user(conf, &dlp->config, sizeof(struct dlci_conf)))
230			return -EFAULT;
231	}
232
233	return 0;
234}
235
236static int dlci_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
237{
238	struct dlci_local *dlp;
239
240	if (!capable(CAP_NET_ADMIN))
241		return -EPERM;
242
243	dlp = netdev_priv(dev);
244
245	switch (cmd)
246	{
247		case DLCI_GET_SLAVE:
248			if (!*(short *)(dev->dev_addr))
249				return -EINVAL;
250
251			strncpy(ifr->ifr_slave, dlp->slave->name, sizeof(ifr->ifr_slave));
252			break;
253
254		case DLCI_GET_CONF:
255		case DLCI_SET_CONF:
256			if (!*(short *)(dev->dev_addr))
257				return -EINVAL;
258
259			return dlci_config(dev, ifr->ifr_data, cmd == DLCI_GET_CONF);
260
261		default:
262			return -EOPNOTSUPP;
263	}
264	return 0;
265}
266
267static int dlci_change_mtu(struct net_device *dev, int new_mtu)
268{
269	struct dlci_local *dlp = netdev_priv(dev);
270
271	return dev_set_mtu(dlp->slave, new_mtu);
272}
273
274static int dlci_open(struct net_device *dev)
275{
276	struct dlci_local	*dlp;
277	struct frad_local	*flp;
278	int			err;
279
280	dlp = netdev_priv(dev);
281
282	if (!*(short *)(dev->dev_addr))
283		return -EINVAL;
284
285	if (!netif_running(dlp->slave))
286		return -ENOTCONN;
287
288	flp = netdev_priv(dlp->slave);
289	err = (*flp->activate)(dlp->slave, dev);
290	if (err)
291		return err;
292
293	netif_start_queue(dev);
294
295	return 0;
296}
297
298static int dlci_close(struct net_device *dev)
299{
300	struct dlci_local	*dlp;
301	struct frad_local	*flp;
302	int			err;
303
304	netif_stop_queue(dev);
305
306	dlp = netdev_priv(dev);
307
308	flp = netdev_priv(dlp->slave);
309	err = (*flp->deactivate)(dlp->slave, dev);
310
311	return 0;
312}
313
314static int dlci_add(struct dlci_add *dlci)
315{
316	struct net_device	*master, *slave;
317	struct dlci_local	*dlp;
318	struct frad_local	*flp;
319	int			err = -EINVAL;
320
321
322	/* validate slave device */
323	slave = dev_get_by_name(&init_net, dlci->devname);
324	if (!slave)
325		return -ENODEV;
326
327	if (slave->type != ARPHRD_FRAD || netdev_priv(slave) == NULL)
328		goto err1;
329
330	/* create device name */
331	master = alloc_netdev(sizeof(struct dlci_local), "dlci%d",
332			      NET_NAME_UNKNOWN, dlci_setup);
333	if (!master) {
334		err = -ENOMEM;
335		goto err1;
336	}
337
338	/* make sure same slave not already registered */
339	rtnl_lock();
340	list_for_each_entry(dlp, &dlci_devs, list) {
341		if (dlp->slave == slave) {
342			err = -EBUSY;
343			goto err2;
344		}
345	}
346
347	*(short *)(master->dev_addr) = dlci->dlci;
348
349	dlp = netdev_priv(master);
350	dlp->slave = slave;
351	dlp->master = master;
352
353	flp = netdev_priv(slave);
354	err = (*flp->assoc)(slave, master);
355	if (err < 0)
356		goto err2;
357
358	err = register_netdevice(master);
359	if (err < 0)
360		goto err2;
361
362	strcpy(dlci->devname, master->name);
363
364	list_add(&dlp->list, &dlci_devs);
365	rtnl_unlock();
366
367	return 0;
368
369 err2:
370	rtnl_unlock();
371	free_netdev(master);
372 err1:
373	dev_put(slave);
374	return err;
375}
376
377static int dlci_del(struct dlci_add *dlci)
378{
379	struct dlci_local	*dlp;
380	struct frad_local	*flp;
381	struct net_device	*master, *slave;
382	int			err;
383	bool			found = false;
384
385	rtnl_lock();
386
387	/* validate slave device */
388	master = __dev_get_by_name(&init_net, dlci->devname);
389	if (!master) {
390		err = -ENODEV;
391		goto out;
392	}
393
394	list_for_each_entry(dlp, &dlci_devs, list) {
395		if (dlp->master == master) {
396			found = true;
397			break;
398		}
399	}
400	if (!found) {
401		err = -ENODEV;
402		goto out;
403	}
404
405	if (netif_running(master)) {
406		err = -EBUSY;
407		goto out;
408	}
409
410	dlp = netdev_priv(master);
411	slave = dlp->slave;
412	flp = netdev_priv(slave);
413
414	err = (*flp->deassoc)(slave, master);
415	if (!err) {
416		list_del(&dlp->list);
417
418		unregister_netdevice(master);
419
420		dev_put(slave);
421	}
422out:
423	rtnl_unlock();
424	return err;
425}
426
427static int dlci_ioctl(unsigned int cmd, void __user *arg)
428{
429	struct dlci_add add;
430	int err;
431
432	if (!capable(CAP_NET_ADMIN))
433		return -EPERM;
434
435	if (copy_from_user(&add, arg, sizeof(struct dlci_add)))
436		return -EFAULT;
437
438	switch (cmd)
439	{
440		case SIOCADDDLCI:
441			err = dlci_add(&add);
442
443			if (!err)
444				if (copy_to_user(arg, &add, sizeof(struct dlci_add)))
445					return -EFAULT;
446			break;
447
448		case SIOCDELDLCI:
449			err = dlci_del(&add);
450			break;
451
452		default:
453			err = -EINVAL;
454	}
455
456	return err;
457}
458
459static const struct header_ops dlci_header_ops = {
460	.create	= dlci_header,
461};
462
463static const struct net_device_ops dlci_netdev_ops = {
464	.ndo_open	= dlci_open,
465	.ndo_stop	= dlci_close,
466	.ndo_do_ioctl	= dlci_dev_ioctl,
467	.ndo_start_xmit	= dlci_transmit,
468	.ndo_change_mtu	= dlci_change_mtu,
469};
470
471static void dlci_setup(struct net_device *dev)
472{
473	struct dlci_local *dlp = netdev_priv(dev);
474
475	dev->flags		= 0;
476	dev->header_ops		= &dlci_header_ops;
477	dev->netdev_ops		= &dlci_netdev_ops;
478	dev->destructor		= free_netdev;
479
480	dlp->receive		= dlci_receive;
481
482	dev->type		= ARPHRD_DLCI;
483	dev->hard_header_len	= sizeof(struct frhdr);
484	dev->addr_len		= sizeof(short);
485
486}
487
488/* if slave is unregistering, then cleanup master */
489static int dlci_dev_event(struct notifier_block *unused,
490			  unsigned long event, void *ptr)
491{
492	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
493
494	if (dev_net(dev) != &init_net)
495		return NOTIFY_DONE;
496
497	if (event == NETDEV_UNREGISTER) {
498		struct dlci_local *dlp;
499
500		list_for_each_entry(dlp, &dlci_devs, list) {
501			if (dlp->slave == dev) {
502				list_del(&dlp->list);
503				unregister_netdevice(dlp->master);
504				dev_put(dlp->slave);
505				break;
506			}
507		}
508	}
509	return NOTIFY_DONE;
510}
511
512static struct notifier_block dlci_notifier = {
513	.notifier_call = dlci_dev_event,
514};
515
516static int __init init_dlci(void)
517{
518	dlci_ioctl_set(dlci_ioctl);
519	register_netdevice_notifier(&dlci_notifier);
520
521	printk("%s.\n", version);
522
523	return 0;
524}
525
526static void __exit dlci_exit(void)
527{
528	struct dlci_local	*dlp, *nxt;
529
530	dlci_ioctl_set(NULL);
531	unregister_netdevice_notifier(&dlci_notifier);
532
533	rtnl_lock();
534	list_for_each_entry_safe(dlp, nxt, &dlci_devs, list) {
535		unregister_netdevice(dlp->master);
536		dev_put(dlp->slave);
537	}
538	rtnl_unlock();
539}
540
541module_init(init_dlci);
542module_exit(dlci_exit);
543
544MODULE_AUTHOR("Mike McLagan");
545MODULE_DESCRIPTION("Frame Relay DLCI layer");
546MODULE_LICENSE("GPL");
547