[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / x25 / x25_link.c

/*
 *	X.25 Packet Layer release 002
 *
 *	This is ALPHA test software. This code may break your machine,
 *	randomly fail to work with new releases, misbehave and/or generally
 *	screw up. It might even work.
 *
 *	This code REQUIRES 2.1.15 or higher
 *
 *	This module:
 *		This module is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 *	History
 *	X.25 001	Jonathan Naylor	  Started coding.
 *	X.25 002	Jonathan Naylor	  New timer architecture.
 *	mar/20/00	Daniela Squassoni Disabling/enabling of facilities
 *					  negotiation.
 *	2000-09-04	Henner Eisen	  dev_hold() / dev_put() for x25_neigh.
 */

#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <asm/uaccess.h>
#include <linux/init.h>
#include <net/x25.h>

static struct list_head x25_neigh_list = LIST_HEAD_INIT(x25_neigh_list);
static DEFINE_RWLOCK(x25_neigh_list_lock);

static void x25_t20timer_expiry(unsigned long);

static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
static void x25_transmit_restart_request(struct x25_neigh *nb);

/*
 *	Linux set/reset timer routines
 */
static inline void x25_start_t20timer(struct x25_neigh *nb)
{
	mod_timer(&nb->t20timer, jiffies + nb->t20);
}

static void x25_t20timer_expiry(unsigned long param)
{
	struct x25_neigh *nb = (struct x25_neigh *)param;

	x25_transmit_restart_request(nb);

	x25_start_t20timer(nb);
}

static inline void x25_stop_t20timer(struct x25_neigh *nb)
{
	del_timer(&nb->t20timer);
}

static inline int x25_t20timer_pending(struct x25_neigh *nb)
{
	return timer_pending(&nb->t20timer);
}

/*
 *	This handles all restart and diagnostic frames.
 */
void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
		      unsigned short frametype)
{
	struct sk_buff *skbn;
	int confirm;

	switch (frametype) {
		case X25_RESTART_REQUEST:
			confirm = !x25_t20timer_pending(nb);
			x25_stop_t20timer(nb);
			nb->state = X25_LINK_STATE_3;
			if (confirm)
				x25_transmit_restart_confirmation(nb);
			break;

		case X25_RESTART_CONFIRMATION:
			x25_stop_t20timer(nb);
			nb->state = X25_LINK_STATE_3;
			break;

		case X25_DIAGNOSTIC:
			printk(KERN_WARNING "x25: diagnostic #%d - "
			       "%02X %02X %02X\n",
			       skb->data[3], skb->data[4],
			       skb->data[5], skb->data[6]);
			break;

		default:
			printk(KERN_WARNING "x25: received unknown %02X "
			       "with LCI 000\n", frametype);
			break;
	}

	if (nb->state == X25_LINK_STATE_3)
		while ((skbn = skb_dequeue(&nb->queue)) != NULL)
			x25_send_frame(skbn, nb);
}

/*
 *	This routine is called when a Restart Request is needed
 */
static void x25_transmit_restart_request(struct x25_neigh *nb)
{
	unsigned char *dptr;
	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);

	if (!skb)
		return;

	skb_reserve(skb, X25_MAX_L2_LEN);

	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);

	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
	*dptr++ = 0x00;
	*dptr++ = X25_RESTART_REQUEST;
	*dptr++ = 0x00;
	*dptr++ = 0;

	skb->sk = NULL;

	x25_send_frame(skb, nb);
}

/*
 * This routine is called when a Restart Confirmation is needed
 */
static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
{
	unsigned char *dptr;
	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);

	if (!skb)
		return;

	skb_reserve(skb, X25_MAX_L2_LEN);

	dptr = skb_put(skb, X25_STD_MIN_LEN);

	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
	*dptr++ = 0x00;
	*dptr++ = X25_RESTART_CONFIRMATION;

	skb->sk = NULL;

	x25_send_frame(skb, nb);
}

/*
 *	This routine is called when a Clear Request is needed outside of the context
 *	of a connected socket.
 */
void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
				unsigned char cause)
{
	unsigned char *dptr;
	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);

	if (!skb)
		return;

	skb_reserve(skb, X25_MAX_L2_LEN);

	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);

	*dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
					 X25_GFI_EXTSEQ :
					 X25_GFI_STDSEQ);
	*dptr++ = (lci >> 0) & 0xFF;
	*dptr++ = X25_CLEAR_REQUEST;
	*dptr++ = cause;
	*dptr++ = 0x00;

	skb->sk = NULL;

	x25_send_frame(skb, nb);
}

void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
{
	switch (nb->state) {
		case X25_LINK_STATE_0:
			skb_queue_tail(&nb->queue, skb);
			nb->state = X25_LINK_STATE_1;
			x25_establish_link(nb);
			break;
		case X25_LINK_STATE_1:
		case X25_LINK_STATE_2:
			skb_queue_tail(&nb->queue, skb);
			break;
		case X25_LINK_STATE_3:
			x25_send_frame(skb, nb);
			break;
	}
}

/*
 *	Called when the link layer has become established.
 */
void x25_link_established(struct x25_neigh *nb)
{
	switch (nb->state) {
		case X25_LINK_STATE_0:
			nb->state = X25_LINK_STATE_2;
			break;
		case X25_LINK_STATE_1:
			x25_transmit_restart_request(nb);
			nb->state = X25_LINK_STATE_2;
			x25_start_t20timer(nb);
			break;
	}
}

/*
 *	Called when the link layer has terminated, or an establishment
 *	request has failed.
 */

void x25_link_terminated(struct x25_neigh *nb)
{
	nb->state = X25_LINK_STATE_0;
	/* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
	x25_kill_by_neigh(nb);
}

/*
 *	Add a new device.
 */
void x25_link_device_up(struct net_device *dev)
{
	struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);

	if (!nb)
		return;

	skb_queue_head_init(&nb->queue);

	init_timer(&nb->t20timer);
	nb->t20timer.data     = (unsigned long)nb;
	nb->t20timer.function = &x25_t20timer_expiry;

	dev_hold(dev);
	nb->dev      = dev;
	nb->state    = X25_LINK_STATE_0;
	nb->extended = 0;
	/*
	 * Enables negotiation
	 */
	nb->global_facil_mask = X25_MASK_REVERSE |
				       X25_MASK_THROUGHPUT |
				       X25_MASK_PACKET_SIZE |
				       X25_MASK_WINDOW_SIZE;
	nb->t20      = sysctl_x25_restart_request_timeout;
	atomic_set(&nb->refcnt, 1);

	write_lock_bh(&x25_neigh_list_lock);
	list_add(&nb->node, &x25_neigh_list);
	write_unlock_bh(&x25_neigh_list_lock);
}

/**
 *	__x25_remove_neigh - remove neighbour from x25_neigh_list
 *	@nb - neigh to remove
 *
 *	Remove neighbour from x25_neigh_list. If it was there.
 *	Caller must hold x25_neigh_list_lock.
 */
static void __x25_remove_neigh(struct x25_neigh *nb)
{
	skb_queue_purge(&nb->queue);
	x25_stop_t20timer(nb);

	if (nb->node.next) {
		list_del(&nb->node);
		x25_neigh_put(nb);
	}
}

/*
 *	A device has been removed, remove its links.
 */
void x25_link_device_down(struct net_device *dev)
{
	struct x25_neigh *nb;
	struct list_head *entry, *tmp;

	write_lock_bh(&x25_neigh_list_lock);

	list_for_each_safe(entry, tmp, &x25_neigh_list) {
		nb = list_entry(entry, struct x25_neigh, node);

		if (nb->dev == dev) {
			__x25_remove_neigh(nb);
			dev_put(dev);
		}
	}

	write_unlock_bh(&x25_neigh_list_lock);
}

/*
 *	Given a device, return the neighbour address.
 */
struct x25_neigh *x25_get_neigh(struct net_device *dev)
{
	struct x25_neigh *nb, *use = NULL;
	struct list_head *entry;

	read_lock_bh(&x25_neigh_list_lock);
	list_for_each(entry, &x25_neigh_list) {
		nb = list_entry(entry, struct x25_neigh, node);

		if (nb->dev == dev) {
			use = nb;
			break;
		}
	}

	if (use)
		x25_neigh_hold(use);
	read_unlock_bh(&x25_neigh_list_lock);
	return use;
}

/*
 *	Handle the ioctls that control the subscription functions.
 */
int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
{
	struct x25_subscrip_struct x25_subscr;
	struct x25_neigh *nb;
	struct net_device *dev;
	int rc = -EINVAL;

	if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
		goto out;

	rc = -EFAULT;
	if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
		goto out;

	rc = -EINVAL;
	if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
		goto out;

	if ((nb = x25_get_neigh(dev)) == NULL)
		goto out_dev_put;

	dev_put(dev);

	if (cmd == SIOCX25GSUBSCRIP) {
		x25_subscr.extended	     = nb->extended;
		x25_subscr.global_facil_mask = nb->global_facil_mask;
		rc = copy_to_user(arg, &x25_subscr,
				  sizeof(x25_subscr)) ? -EFAULT : 0;
	} else {
		rc = -EINVAL;
		if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
			rc = 0;
			nb->extended	     = x25_subscr.extended;
			nb->global_facil_mask = x25_subscr.global_facil_mask;
		}
	}
	x25_neigh_put(nb);
out:
	return rc;
out_dev_put:
	dev_put(dev);
	goto out;
}


/*
 *	Release all memory associated with X.25 neighbour structures.
 */
void __exit x25_link_free(void)
{
	struct x25_neigh *nb;
	struct list_head *entry, *tmp;

	write_lock_bh(&x25_neigh_list_lock);

	list_for_each_safe(entry, tmp, &x25_neigh_list) {
		nb = list_entry(entry, struct x25_neigh, node);
		__x25_remove_neigh(nb);
	}
	write_unlock_bh(&x25_neigh_list_lock);
}
Commit	Line	Data
1da177e4 LT	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
f8e1d201	6	* screw up. It might even work.
1da177e4 LT	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.
f8e1d201	19	* mar/20/00 Daniela Squassoni Disabling/enabling of facilities
1da177e4 LT	20	* negotiation.
	21	* 2000-09-04 Henner Eisen dev_hold() / dev_put() for x25_neigh.
	22	*/
	23
	24	#include <linux/kernel.h>
	25	#include <linux/jiffies.h>
	26	#include <linux/timer.h>
	27	#include <linux/netdevice.h>
	28	#include <linux/skbuff.h>
	29	#include <asm/uaccess.h>
	30	#include <linux/init.h>
	31	#include <net/x25.h>
	32
	33	static struct list_head x25_neigh_list = LIST_HEAD_INIT(x25_neigh_list);
	34	static DEFINE_RWLOCK(x25_neigh_list_lock);
	35
	36	static void x25_t20timer_expiry(unsigned long);
	37
	38	static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
	39	static void x25_transmit_restart_request(struct x25_neigh *nb);
	40
	41	/*
	42	* Linux set/reset timer routines
	43	*/
	44	static inline void x25_start_t20timer(struct x25_neigh *nb)
	45	{
	46	mod_timer(&nb->t20timer, jiffies + nb->t20);
	47	}
	48
	49	static void x25_t20timer_expiry(unsigned long param)
	50	{
	51	struct x25_neigh nb = (struct x25_neigh )param;
	52
	53	x25_transmit_restart_request(nb);
	54
	55	x25_start_t20timer(nb);
	56	}
	57
	58	static inline void x25_stop_t20timer(struct x25_neigh *nb)
	59	{
	60	del_timer(&nb->t20timer);
	61	}
	62
	63	static inline int x25_t20timer_pending(struct x25_neigh *nb)
	64	{
	65	return timer_pending(&nb->t20timer);
	66	}
	67
	68	/*
	69	* This handles all restart and diagnostic frames.
	70	*/
	71	void x25_link_control(struct sk_buff skb, struct x25_neigh nb,
	72	unsigned short frametype)
	73	{
	74	struct sk_buff *skbn;
	75	int confirm;
	76
	77	switch (frametype) {
	78	case X25_RESTART_REQUEST:
	79	confirm = !x25_t20timer_pending(nb);
	80	x25_stop_t20timer(nb);
	81	nb->state = X25_LINK_STATE_3;
	82	if (confirm)
	83	x25_transmit_restart_confirmation(nb);
84	break;
85
86	case X25_RESTART_CONFIRMATION:
87	x25_stop_t20timer(nb);
88	nb->state = X25_LINK_STATE_3;
89	break;
90
91	case X25_DIAGNOSTIC:
92	printk(KERN_WARNING "x25: diagnostic #%d - "
93	"%02X %02X %02X\n",
94	skb->data[3], skb->data[4],
95	skb->data[5], skb->data[6]);
96	break;
f8e1d201	97
1da177e4 LT	98	default:
	99	printk(KERN_WARNING "x25: received unknown %02X "
	100	"with LCI 000\n", frametype);
	101	break;
	102	}
	103
	104	if (nb->state == X25_LINK_STATE_3)
	105	while ((skbn = skb_dequeue(&nb->queue)) != NULL)
	106	x25_send_frame(skbn, nb);
	107	}
	108
	109	/*
	110	* This routine is called when a Restart Request is needed
	111	*/
	112	static void x25_transmit_restart_request(struct x25_neigh *nb)
	113	{
	114	unsigned char *dptr;
	115	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
	116	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
	117
	118	if (!skb)
	119	return;
	120
	121	skb_reserve(skb, X25_MAX_L2_LEN);
	122
	123	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
	124
	125	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
	126	*dptr++ = 0x00;
	127	*dptr++ = X25_RESTART_REQUEST;
	128	*dptr++ = 0x00;
	129	*dptr++ = 0;
	130
	131	skb->sk = NULL;
	132
	133	x25_send_frame(skb, nb);
	134	}
	135
	136	/*
	137	* This routine is called when a Restart Confirmation is needed
	138	*/
	139	static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
	140	{
	141	unsigned char *dptr;
	142	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
	143	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
	144
	145	if (!skb)
	146	return;
	147
	148	skb_reserve(skb, X25_MAX_L2_LEN);
	149
	150	dptr = skb_put(skb, X25_STD_MIN_LEN);
	151
	152	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
	153	*dptr++ = 0x00;
	154	*dptr++ = X25_RESTART_CONFIRMATION;
	155
	156	skb->sk = NULL;
	157
	158	x25_send_frame(skb, nb);
	159	}
	160
	161	/*
162	* This routine is called when a Clear Request is needed outside of the context
163	* of a connected socket.
164	*/
165	void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
166	unsigned char cause)
167	{
168	unsigned char *dptr;
169	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
170	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
171
172	if (!skb)
173	return;
174
175	skb_reserve(skb, X25_MAX_L2_LEN);
176
177	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
178
179	*dptr++ = ((lci >> 8) & 0x0F) \| (nb->extended ?
180	X25_GFI_EXTSEQ :
181	X25_GFI_STDSEQ);
182	*dptr++ = (lci >> 0) & 0xFF;
183	*dptr++ = X25_CLEAR_REQUEST;
184	*dptr++ = cause;
185	*dptr++ = 0x00;
186
187	skb->sk = NULL;
188
189	x25_send_frame(skb, nb);
190	}
191
192	void x25_transmit_link(struct sk_buff skb, struct x25_neigh nb)
193	{
194	switch (nb->state) {
195	case X25_LINK_STATE_0:
196	skb_queue_tail(&nb->queue, skb);
197	nb->state = X25_LINK_STATE_1;
198	x25_establish_link(nb);
199	break;
200	case X25_LINK_STATE_1:
201	case X25_LINK_STATE_2:
202	skb_queue_tail(&nb->queue, skb);
203	break;
204	case X25_LINK_STATE_3:
205	x25_send_frame(skb, nb);
206	break;
207	}
208	}
209
210	/*
211	* Called when the link layer has become established.
212	*/
213	void x25_link_established(struct x25_neigh *nb)
214	{
215	switch (nb->state) {
216	case X25_LINK_STATE_0:
217	nb->state = X25_LINK_STATE_2;
218	break;
219	case X25_LINK_STATE_1:
220	x25_transmit_restart_request(nb);
221	nb->state = X25_LINK_STATE_2;
222	x25_start_t20timer(nb);
223	break;
224	}
225	}
226
227	/*
228	* Called when the link layer has terminated, or an establishment
229	* request has failed.
230	*/
231
232	void x25_link_terminated(struct x25_neigh *nb)
233	{
234	nb->state = X25_LINK_STATE_0;
235	/* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
236	x25_kill_by_neigh(nb);
237	}
238
239	/*
240	* Add a new device.
241	*/
242	void x25_link_device_up(struct net_device *dev)
243	{
244	struct x25_neigh nb = kmalloc(sizeof(nb), GFP_ATOMIC);
245
246	if (!nb)
247	return;
248
249	skb_queue_head_init(&nb->queue);
250
251	init_timer(&nb->t20timer);
252	nb->t20timer.data = (unsigned long)nb;
253	nb->t20timer.function = &x25_t20timer_expiry;
254
255	dev_hold(dev);
256	nb->dev = dev;
257	nb->state = X25_LINK_STATE_0;
258	nb->extended = 0;
259	/*
260	* Enables negotiation
261	*/
262	nb->global_facil_mask = X25_MASK_REVERSE \|
263	X25_MASK_THROUGHPUT \|
264	X25_MASK_PACKET_SIZE \|
265	X25_MASK_WINDOW_SIZE;
266	nb->t20 = sysctl_x25_restart_request_timeout;
267	atomic_set(&nb->refcnt, 1);
268
269	write_lock_bh(&x25_neigh_list_lock);
270	list_add(&nb->node, &x25_neigh_list);
271	write_unlock_bh(&x25_neigh_list_lock);
272	}
273
274	/**
275	* __x25_remove_neigh - remove neighbour from x25_neigh_list
276	* @nb - neigh to remove
277	*
278	* Remove neighbour from x25_neigh_list. If it was there.
279	* Caller must hold x25_neigh_list_lock.
280	*/
281	static void __x25_remove_neigh(struct x25_neigh *nb)
282	{
283	skb_queue_purge(&nb->queue);
284	x25_stop_t20timer(nb);
285
286	if (nb->node.next) {
287	list_del(&nb->node);
288	x25_neigh_put(nb);
289	}
290	}
291
292	/*
293	* A device has been removed, remove its links.
294	*/
295	void x25_link_device_down(struct net_device *dev)
296	{
297	struct x25_neigh *nb;
298	struct list_head entry, tmp;
299
300	write_lock_bh(&x25_neigh_list_lock);
301
302	list_for_each_safe(entry, tmp, &x25_neigh_list) {
303	nb = list_entry(entry, struct x25_neigh, node);
304
305	if (nb->dev == dev) {
306	__x25_remove_neigh(nb);
307	dev_put(dev);
308	}
309	}
310
311	write_unlock_bh(&x25_neigh_list_lock);
312	}
313
314	/*
315	* Given a device, return the neighbour address.
316	*/
317	struct x25_neigh x25_get_neigh(struct net_device dev)
318	{
319	struct x25_neigh nb, use = NULL;
320	struct list_head *entry;
321
322	read_lock_bh(&x25_neigh_list_lock);
323	list_for_each(entry, &x25_neigh_list) {
324	nb = list_entry(entry, struct x25_neigh, node);
325
326	if (nb->dev == dev) {
327	use = nb;
328	break;
329	}
330	}
331
332	if (use)
333	x25_neigh_hold(use);
334	read_unlock_bh(&x25_neigh_list_lock);
335	return use;
336	}
337
338	/*
339	* Handle the ioctls that control the subscription functions.
340	*/
341	int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
342	{
343	struct x25_subscrip_struct x25_subscr;
344	struct x25_neigh *nb;
345	struct net_device *dev;
346	int rc = -EINVAL;
347
348	if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
349	goto out;
350
351	rc = -EFAULT;
352	if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
353	goto out;
354
355	rc = -EINVAL;
356	if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
357	goto out;
358
359	if ((nb = x25_get_neigh(dev)) == NULL)
360	goto out_dev_put;
361
362	dev_put(dev);
363
364	if (cmd == SIOCX25GSUBSCRIP) {
365	x25_subscr.extended = nb->extended;
366	x25_subscr.global_facil_mask = nb->global_facil_mask;
367	rc = copy_to_user(arg, &x25_subscr,
368	sizeof(x25_subscr)) ? -EFAULT : 0;
369	} else {
370	rc = -EINVAL;
371	if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
372	rc = 0;
373	nb->extended = x25_subscr.extended;
374	nb->global_facil_mask = x25_subscr.global_facil_mask;
375	}
376	}
377	x25_neigh_put(nb);
378	out:
379	return rc;
380	out_dev_put:
381	dev_put(dev);
382	goto out;
383	}
384
385
386	/*
387	* Release all memory associated with X.25 neighbour structures.
388	*/
389	void __exit x25_link_free(void)
390	{
391	struct x25_neigh *nb;
392	struct list_head entry, tmp;
393
394	write_lock_bh(&x25_neigh_list_lock);
395
396	list_for_each_safe(entry, tmp, &x25_neigh_list) {
397	nb = list_entry(entry, struct x25_neigh, node);
398	__x25_remove_neigh(nb);
399	}
400	write_unlock_bh(&x25_neigh_list_lock);
401	}