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v4.6
 
  1/*
  2 *	X.25 Packet Layer release 002
  3 *
  4 *	This is ALPHA test software. This code may break your machine,
  5 *	randomly fail to work with new releases, misbehave and/or generally
  6 *	screw up. It might even work.
  7 *
  8 *	This code REQUIRES 2.1.15 or higher
  9 *
 10 *	This module:
 11 *		This module is free software; you can redistribute it and/or
 12 *		modify it under the terms of the GNU General Public License
 13 *		as published by the Free Software Foundation; either version
 14 *		2 of the License, or (at your option) any later version.
 15 *
 16 *	History
 17 *	X.25 001	Jonathan Naylor	  Started coding.
 18 *	X.25 002	Jonathan Naylor	  New timer architecture.
 19 *	mar/20/00	Daniela Squassoni Disabling/enabling of facilities
 20 *					  negotiation.
 21 *	2000-09-04	Henner Eisen	  dev_hold() / dev_put() for x25_neigh.
 22 */
 23
 24#define pr_fmt(fmt) "X25: " fmt
 25
 26#include <linux/kernel.h>
 27#include <linux/jiffies.h>
 28#include <linux/timer.h>
 29#include <linux/slab.h>
 30#include <linux/netdevice.h>
 31#include <linux/skbuff.h>
 32#include <asm/uaccess.h>
 33#include <linux/init.h>
 34#include <net/x25.h>
 35
 36LIST_HEAD(x25_neigh_list);
 37DEFINE_RWLOCK(x25_neigh_list_lock);
 38
 39static void x25_t20timer_expiry(unsigned long);
 40
 41static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
 42static void x25_transmit_restart_request(struct x25_neigh *nb);
 43
 44/*
 45 *	Linux set/reset timer routines
 46 */
 47static inline void x25_start_t20timer(struct x25_neigh *nb)
 48{
 49	mod_timer(&nb->t20timer, jiffies + nb->t20);
 50}
 51
 52static void x25_t20timer_expiry(unsigned long param)
 53{
 54	struct x25_neigh *nb = (struct x25_neigh *)param;
 55
 56	x25_transmit_restart_request(nb);
 57
 58	x25_start_t20timer(nb);
 59}
 60
 61static inline void x25_stop_t20timer(struct x25_neigh *nb)
 62{
 63	del_timer(&nb->t20timer);
 64}
 65
 66static inline int x25_t20timer_pending(struct x25_neigh *nb)
 67{
 68	return timer_pending(&nb->t20timer);
 69}
 70
 71/*
 72 *	This handles all restart and diagnostic frames.
 73 */
 74void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
 75		      unsigned short frametype)
 76{
 77	struct sk_buff *skbn;
 78	int confirm;
 79
 80	switch (frametype) {
 81	case X25_RESTART_REQUEST:
 82		confirm = !x25_t20timer_pending(nb);
 83		x25_stop_t20timer(nb);
 84		nb->state = X25_LINK_STATE_3;
 85		if (confirm)
 
 
 
 
 
 
 
 
 
 
 
 
 86			x25_transmit_restart_confirmation(nb);
 
 
 87		break;
 88
 89	case X25_RESTART_CONFIRMATION:
 90		x25_stop_t20timer(nb);
 91		nb->state = X25_LINK_STATE_3;
 
 
 
 
 
 
 
 
 
 
 
 
 92		break;
 93
 94	case X25_DIAGNOSTIC:
 95		if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4))
 96			break;
 97
 98		pr_warn("diagnostic #%d - %02X %02X %02X\n",
 99		       skb->data[3], skb->data[4],
100		       skb->data[5], skb->data[6]);
101		break;
102
103	default:
104		pr_warn("received unknown %02X with LCI 000\n",
105		       frametype);
106		break;
107	}
108
109	if (nb->state == X25_LINK_STATE_3)
110		while ((skbn = skb_dequeue(&nb->queue)) != NULL)
111			x25_send_frame(skbn, nb);
112}
113
114/*
115 *	This routine is called when a Restart Request is needed
116 */
117static void x25_transmit_restart_request(struct x25_neigh *nb)
118{
119	unsigned char *dptr;
120	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
121	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
122
123	if (!skb)
124		return;
125
126	skb_reserve(skb, X25_MAX_L2_LEN);
127
128	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
129
130	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
131	*dptr++ = 0x00;
132	*dptr++ = X25_RESTART_REQUEST;
133	*dptr++ = 0x00;
134	*dptr++ = 0;
135
136	skb->sk = NULL;
137
138	x25_send_frame(skb, nb);
139}
140
141/*
142 * This routine is called when a Restart Confirmation is needed
143 */
144static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
145{
146	unsigned char *dptr;
147	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
148	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
149
150	if (!skb)
151		return;
152
153	skb_reserve(skb, X25_MAX_L2_LEN);
154
155	dptr = skb_put(skb, X25_STD_MIN_LEN);
156
157	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
158	*dptr++ = 0x00;
159	*dptr++ = X25_RESTART_CONFIRMATION;
160
161	skb->sk = NULL;
162
163	x25_send_frame(skb, nb);
164}
165
166/*
167 *	This routine is called when a Clear Request is needed outside of the context
168 *	of a connected socket.
169 */
170void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
171				unsigned char cause)
172{
173	unsigned char *dptr;
174	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
175	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
176
177	if (!skb)
178		return;
179
180	skb_reserve(skb, X25_MAX_L2_LEN);
181
182	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
183
184	*dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
185					 X25_GFI_EXTSEQ :
186					 X25_GFI_STDSEQ);
187	*dptr++ = (lci >> 0) & 0xFF;
188	*dptr++ = X25_CLEAR_REQUEST;
189	*dptr++ = cause;
190	*dptr++ = 0x00;
191
192	skb->sk = NULL;
193
194	x25_send_frame(skb, nb);
195}
196
197void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
198{
199	switch (nb->state) {
200	case X25_LINK_STATE_0:
201		skb_queue_tail(&nb->queue, skb);
202		nb->state = X25_LINK_STATE_1;
203		x25_establish_link(nb);
204		break;
205	case X25_LINK_STATE_1:
206	case X25_LINK_STATE_2:
207		skb_queue_tail(&nb->queue, skb);
208		break;
209	case X25_LINK_STATE_3:
210		x25_send_frame(skb, nb);
211		break;
212	}
213}
214
215/*
216 *	Called when the link layer has become established.
217 */
218void x25_link_established(struct x25_neigh *nb)
219{
220	switch (nb->state) {
221	case X25_LINK_STATE_0:
222		nb->state = X25_LINK_STATE_2;
223		break;
224	case X25_LINK_STATE_1:
225		x25_transmit_restart_request(nb);
226		nb->state = X25_LINK_STATE_2;
227		x25_start_t20timer(nb);
228		break;
229	}
230}
231
232/*
233 *	Called when the link layer has terminated, or an establishment
234 *	request has failed.
235 */
236
237void x25_link_terminated(struct x25_neigh *nb)
238{
239	nb->state = X25_LINK_STATE_0;
 
 
 
240	/* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
241	x25_kill_by_neigh(nb);
242}
243
244/*
245 *	Add a new device.
246 */
247void x25_link_device_up(struct net_device *dev)
248{
249	struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);
250
251	if (!nb)
252		return;
253
254	skb_queue_head_init(&nb->queue);
255	setup_timer(&nb->t20timer, x25_t20timer_expiry, (unsigned long)nb);
256
257	dev_hold(dev);
258	nb->dev      = dev;
259	nb->state    = X25_LINK_STATE_0;
260	nb->extended = 0;
261	/*
262	 * Enables negotiation
263	 */
264	nb->global_facil_mask = X25_MASK_REVERSE |
265				       X25_MASK_THROUGHPUT |
266				       X25_MASK_PACKET_SIZE |
267				       X25_MASK_WINDOW_SIZE;
268	nb->t20      = sysctl_x25_restart_request_timeout;
269	atomic_set(&nb->refcnt, 1);
270
271	write_lock_bh(&x25_neigh_list_lock);
272	list_add(&nb->node, &x25_neigh_list);
273	write_unlock_bh(&x25_neigh_list_lock);
274}
275
276/**
277 *	__x25_remove_neigh - remove neighbour from x25_neigh_list
278 *	@nb - neigh to remove
279 *
280 *	Remove neighbour from x25_neigh_list. If it was there.
281 *	Caller must hold x25_neigh_list_lock.
282 */
283static void __x25_remove_neigh(struct x25_neigh *nb)
284{
285	skb_queue_purge(&nb->queue);
286	x25_stop_t20timer(nb);
287
288	if (nb->node.next) {
289		list_del(&nb->node);
290		x25_neigh_put(nb);
291	}
292}
293
294/*
295 *	A device has been removed, remove its links.
296 */
297void x25_link_device_down(struct net_device *dev)
298{
299	struct x25_neigh *nb;
300	struct list_head *entry, *tmp;
301
302	write_lock_bh(&x25_neigh_list_lock);
303
304	list_for_each_safe(entry, tmp, &x25_neigh_list) {
305		nb = list_entry(entry, struct x25_neigh, node);
306
307		if (nb->dev == dev) {
308			__x25_remove_neigh(nb);
309			dev_put(dev);
310		}
311	}
312
313	write_unlock_bh(&x25_neigh_list_lock);
314}
315
316/*
317 *	Given a device, return the neighbour address.
318 */
319struct x25_neigh *x25_get_neigh(struct net_device *dev)
320{
321	struct x25_neigh *nb, *use = NULL;
322	struct list_head *entry;
323
324	read_lock_bh(&x25_neigh_list_lock);
325	list_for_each(entry, &x25_neigh_list) {
326		nb = list_entry(entry, struct x25_neigh, node);
327
328		if (nb->dev == dev) {
329			use = nb;
330			break;
331		}
332	}
333
334	if (use)
335		x25_neigh_hold(use);
336	read_unlock_bh(&x25_neigh_list_lock);
337	return use;
338}
339
340/*
341 *	Handle the ioctls that control the subscription functions.
342 */
343int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
344{
345	struct x25_subscrip_struct x25_subscr;
346	struct x25_neigh *nb;
347	struct net_device *dev;
348	int rc = -EINVAL;
349
350	if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
351		goto out;
352
353	rc = -EFAULT;
354	if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
355		goto out;
356
357	rc = -EINVAL;
358	if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
359		goto out;
360
361	if ((nb = x25_get_neigh(dev)) == NULL)
362		goto out_dev_put;
363
364	dev_put(dev);
365
366	if (cmd == SIOCX25GSUBSCRIP) {
367		read_lock_bh(&x25_neigh_list_lock);
368		x25_subscr.extended	     = nb->extended;
369		x25_subscr.global_facil_mask = nb->global_facil_mask;
370		read_unlock_bh(&x25_neigh_list_lock);
371		rc = copy_to_user(arg, &x25_subscr,
372				  sizeof(x25_subscr)) ? -EFAULT : 0;
373	} else {
374		rc = -EINVAL;
375		if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
376			rc = 0;
377			write_lock_bh(&x25_neigh_list_lock);
378			nb->extended	     = x25_subscr.extended;
379			nb->global_facil_mask = x25_subscr.global_facil_mask;
380			write_unlock_bh(&x25_neigh_list_lock);
381		}
382	}
383	x25_neigh_put(nb);
384out:
385	return rc;
386out_dev_put:
387	dev_put(dev);
388	goto out;
389}
390
391
392/*
393 *	Release all memory associated with X.25 neighbour structures.
394 */
395void __exit x25_link_free(void)
396{
397	struct x25_neigh *nb;
398	struct list_head *entry, *tmp;
399
400	write_lock_bh(&x25_neigh_list_lock);
401
402	list_for_each_safe(entry, tmp, &x25_neigh_list) {
403		struct net_device *dev;
404
405		nb = list_entry(entry, struct x25_neigh, node);
406		dev = nb->dev;
407		__x25_remove_neigh(nb);
408		dev_put(dev);
409	}
410	write_unlock_bh(&x25_neigh_list_lock);
411}
v6.13.7
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *	X.25 Packet Layer release 002
  4 *
  5 *	This is ALPHA test software. This code may break your machine,
  6 *	randomly fail to work with new releases, misbehave and/or generally
  7 *	screw up. It might even work.
  8 *
  9 *	This code REQUIRES 2.1.15 or higher
 10 *
 
 
 
 
 
 
 11 *	History
 12 *	X.25 001	Jonathan Naylor	  Started coding.
 13 *	X.25 002	Jonathan Naylor	  New timer architecture.
 14 *	mar/20/00	Daniela Squassoni Disabling/enabling of facilities
 15 *					  negotiation.
 16 *	2000-09-04	Henner Eisen	  dev_hold() / dev_put() for x25_neigh.
 17 */
 18
 19#define pr_fmt(fmt) "X25: " fmt
 20
 21#include <linux/kernel.h>
 22#include <linux/jiffies.h>
 23#include <linux/timer.h>
 24#include <linux/slab.h>
 25#include <linux/netdevice.h>
 26#include <linux/skbuff.h>
 27#include <linux/uaccess.h>
 28#include <linux/init.h>
 29#include <net/x25.h>
 30
 31LIST_HEAD(x25_neigh_list);
 32DEFINE_RWLOCK(x25_neigh_list_lock);
 33
 34static void x25_t20timer_expiry(struct timer_list *);
 35
 36static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
 37static void x25_transmit_restart_request(struct x25_neigh *nb);
 38
 39/*
 40 *	Linux set/reset timer routines
 41 */
 42static inline void x25_start_t20timer(struct x25_neigh *nb)
 43{
 44	mod_timer(&nb->t20timer, jiffies + nb->t20);
 45}
 46
 47static void x25_t20timer_expiry(struct timer_list *t)
 48{
 49	struct x25_neigh *nb = from_timer(nb, t, t20timer);
 50
 51	x25_transmit_restart_request(nb);
 52
 53	x25_start_t20timer(nb);
 54}
 55
 56static inline void x25_stop_t20timer(struct x25_neigh *nb)
 57{
 58	del_timer(&nb->t20timer);
 59}
 60
 
 
 
 
 
 61/*
 62 *	This handles all restart and diagnostic frames.
 63 */
 64void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
 65		      unsigned short frametype)
 66{
 67	struct sk_buff *skbn;
 
 68
 69	switch (frametype) {
 70	case X25_RESTART_REQUEST:
 71		switch (nb->state) {
 72		case X25_LINK_STATE_0:
 73			/* This can happen when the x25 module just gets loaded
 74			 * and doesn't know layer 2 has already connected
 75			 */
 76			nb->state = X25_LINK_STATE_3;
 77			x25_transmit_restart_confirmation(nb);
 78			break;
 79		case X25_LINK_STATE_2:
 80			x25_stop_t20timer(nb);
 81			nb->state = X25_LINK_STATE_3;
 82			break;
 83		case X25_LINK_STATE_3:
 84			/* clear existing virtual calls */
 85			x25_kill_by_neigh(nb);
 86
 87			x25_transmit_restart_confirmation(nb);
 88			break;
 89		}
 90		break;
 91
 92	case X25_RESTART_CONFIRMATION:
 93		switch (nb->state) {
 94		case X25_LINK_STATE_2:
 95			x25_stop_t20timer(nb);
 96			nb->state = X25_LINK_STATE_3;
 97			break;
 98		case X25_LINK_STATE_3:
 99			/* clear existing virtual calls */
100			x25_kill_by_neigh(nb);
101
102			x25_transmit_restart_request(nb);
103			nb->state = X25_LINK_STATE_2;
104			x25_start_t20timer(nb);
105			break;
106		}
107		break;
108
109	case X25_DIAGNOSTIC:
110		if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4))
111			break;
112
113		pr_warn("diagnostic #%d - %02X %02X %02X\n",
114		       skb->data[3], skb->data[4],
115		       skb->data[5], skb->data[6]);
116		break;
117
118	default:
119		pr_warn("received unknown %02X with LCI 000\n",
120		       frametype);
121		break;
122	}
123
124	if (nb->state == X25_LINK_STATE_3)
125		while ((skbn = skb_dequeue(&nb->queue)) != NULL)
126			x25_send_frame(skbn, nb);
127}
128
129/*
130 *	This routine is called when a Restart Request is needed
131 */
132static void x25_transmit_restart_request(struct x25_neigh *nb)
133{
134	unsigned char *dptr;
135	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
136	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
137
138	if (!skb)
139		return;
140
141	skb_reserve(skb, X25_MAX_L2_LEN);
142
143	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
144
145	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
146	*dptr++ = 0x00;
147	*dptr++ = X25_RESTART_REQUEST;
148	*dptr++ = 0x00;
149	*dptr++ = 0;
150
151	skb->sk = NULL;
152
153	x25_send_frame(skb, nb);
154}
155
156/*
157 * This routine is called when a Restart Confirmation is needed
158 */
159static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
160{
161	unsigned char *dptr;
162	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
163	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
164
165	if (!skb)
166		return;
167
168	skb_reserve(skb, X25_MAX_L2_LEN);
169
170	dptr = skb_put(skb, X25_STD_MIN_LEN);
171
172	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
173	*dptr++ = 0x00;
174	*dptr++ = X25_RESTART_CONFIRMATION;
175
176	skb->sk = NULL;
177
178	x25_send_frame(skb, nb);
179}
180
181/*
182 *	This routine is called when a Clear Request is needed outside of the context
183 *	of a connected socket.
184 */
185void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
186				unsigned char cause)
187{
188	unsigned char *dptr;
189	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
190	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
191
192	if (!skb)
193		return;
194
195	skb_reserve(skb, X25_MAX_L2_LEN);
196
197	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
198
199	*dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
200					 X25_GFI_EXTSEQ :
201					 X25_GFI_STDSEQ);
202	*dptr++ = (lci >> 0) & 0xFF;
203	*dptr++ = X25_CLEAR_REQUEST;
204	*dptr++ = cause;
205	*dptr++ = 0x00;
206
207	skb->sk = NULL;
208
209	x25_send_frame(skb, nb);
210}
211
212void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
213{
214	switch (nb->state) {
215	case X25_LINK_STATE_0:
216		skb_queue_tail(&nb->queue, skb);
217		nb->state = X25_LINK_STATE_1;
218		x25_establish_link(nb);
219		break;
220	case X25_LINK_STATE_1:
221	case X25_LINK_STATE_2:
222		skb_queue_tail(&nb->queue, skb);
223		break;
224	case X25_LINK_STATE_3:
225		x25_send_frame(skb, nb);
226		break;
227	}
228}
229
230/*
231 *	Called when the link layer has become established.
232 */
233void x25_link_established(struct x25_neigh *nb)
234{
235	switch (nb->state) {
236	case X25_LINK_STATE_0:
 
 
237	case X25_LINK_STATE_1:
238		x25_transmit_restart_request(nb);
239		nb->state = X25_LINK_STATE_2;
240		x25_start_t20timer(nb);
241		break;
242	}
243}
244
245/*
246 *	Called when the link layer has terminated, or an establishment
247 *	request has failed.
248 */
249
250void x25_link_terminated(struct x25_neigh *nb)
251{
252	nb->state = X25_LINK_STATE_0;
253	skb_queue_purge(&nb->queue);
254	x25_stop_t20timer(nb);
255
256	/* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
257	x25_kill_by_neigh(nb);
258}
259
260/*
261 *	Add a new device.
262 */
263void x25_link_device_up(struct net_device *dev)
264{
265	struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);
266
267	if (!nb)
268		return;
269
270	skb_queue_head_init(&nb->queue);
271	timer_setup(&nb->t20timer, x25_t20timer_expiry, 0);
272
273	dev_hold(dev);
274	nb->dev      = dev;
275	nb->state    = X25_LINK_STATE_0;
276	nb->extended = 0;
277	/*
278	 * Enables negotiation
279	 */
280	nb->global_facil_mask = X25_MASK_REVERSE |
281				       X25_MASK_THROUGHPUT |
282				       X25_MASK_PACKET_SIZE |
283				       X25_MASK_WINDOW_SIZE;
284	nb->t20      = sysctl_x25_restart_request_timeout;
285	refcount_set(&nb->refcnt, 1);
286
287	write_lock_bh(&x25_neigh_list_lock);
288	list_add(&nb->node, &x25_neigh_list);
289	write_unlock_bh(&x25_neigh_list_lock);
290}
291
292/**
293 *	__x25_remove_neigh - remove neighbour from x25_neigh_list
294 *	@nb: - neigh to remove
295 *
296 *	Remove neighbour from x25_neigh_list. If it was there.
297 *	Caller must hold x25_neigh_list_lock.
298 */
299static void __x25_remove_neigh(struct x25_neigh *nb)
300{
 
 
 
301	if (nb->node.next) {
302		list_del(&nb->node);
303		x25_neigh_put(nb);
304	}
305}
306
307/*
308 *	A device has been removed, remove its links.
309 */
310void x25_link_device_down(struct net_device *dev)
311{
312	struct x25_neigh *nb;
313	struct list_head *entry, *tmp;
314
315	write_lock_bh(&x25_neigh_list_lock);
316
317	list_for_each_safe(entry, tmp, &x25_neigh_list) {
318		nb = list_entry(entry, struct x25_neigh, node);
319
320		if (nb->dev == dev) {
321			__x25_remove_neigh(nb);
322			dev_put(dev);
323		}
324	}
325
326	write_unlock_bh(&x25_neigh_list_lock);
327}
328
329/*
330 *	Given a device, return the neighbour address.
331 */
332struct x25_neigh *x25_get_neigh(struct net_device *dev)
333{
334	struct x25_neigh *nb, *use = NULL;
 
335
336	read_lock_bh(&x25_neigh_list_lock);
337	list_for_each_entry(nb, &x25_neigh_list, node) {
 
 
338		if (nb->dev == dev) {
339			use = nb;
340			break;
341		}
342	}
343
344	if (use)
345		x25_neigh_hold(use);
346	read_unlock_bh(&x25_neigh_list_lock);
347	return use;
348}
349
350/*
351 *	Handle the ioctls that control the subscription functions.
352 */
353int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
354{
355	struct x25_subscrip_struct x25_subscr;
356	struct x25_neigh *nb;
357	struct net_device *dev;
358	int rc = -EINVAL;
359
360	if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
361		goto out;
362
363	rc = -EFAULT;
364	if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
365		goto out;
366
367	rc = -EINVAL;
368	if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
369		goto out;
370
371	if ((nb = x25_get_neigh(dev)) == NULL)
372		goto out_dev_put;
373
374	dev_put(dev);
375
376	if (cmd == SIOCX25GSUBSCRIP) {
377		read_lock_bh(&x25_neigh_list_lock);
378		x25_subscr.extended	     = nb->extended;
379		x25_subscr.global_facil_mask = nb->global_facil_mask;
380		read_unlock_bh(&x25_neigh_list_lock);
381		rc = copy_to_user(arg, &x25_subscr,
382				  sizeof(x25_subscr)) ? -EFAULT : 0;
383	} else {
384		rc = -EINVAL;
385		if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
386			rc = 0;
387			write_lock_bh(&x25_neigh_list_lock);
388			nb->extended	     = x25_subscr.extended;
389			nb->global_facil_mask = x25_subscr.global_facil_mask;
390			write_unlock_bh(&x25_neigh_list_lock);
391		}
392	}
393	x25_neigh_put(nb);
394out:
395	return rc;
396out_dev_put:
397	dev_put(dev);
398	goto out;
399}
400
401
402/*
403 *	Release all memory associated with X.25 neighbour structures.
404 */
405void __exit x25_link_free(void)
406{
407	struct x25_neigh *nb;
408	struct list_head *entry, *tmp;
409
410	write_lock_bh(&x25_neigh_list_lock);
411
412	list_for_each_safe(entry, tmp, &x25_neigh_list) {
413		struct net_device *dev;
414
415		nb = list_entry(entry, struct x25_neigh, node);
416		dev = nb->dev;
417		__x25_remove_neigh(nb);
418		dev_put(dev);
419	}
420	write_unlock_bh(&x25_neigh_list_lock);
421}