net/x25/x25_link.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	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
  *
  *	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.
  */

 #define pr_fmt(fmt) "X25: " fmt

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

 LIST_HEAD(x25_neigh_list);
 DEFINE_RWLOCK(x25_neigh_list_lock);

 static void x25_t20timer_expiry(struct timer_list *);

 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(struct timer_list *t)
 {
 	struct x25_neigh *nb = from_timer(nb, t, t20timer);

 	x25_transmit_restart_request(nb);

 	x25_start_t20timer(nb);
 }

 static inline void x25_stop_t20timer(struct x25_neigh *nb)
 {
 	del_timer(&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;

 	switch (frametype) {
 	case X25_RESTART_REQUEST:
 		switch (nb->state) {
 		case X25_LINK_STATE_0:
 			/* This can happen when the x25 module just gets loaded
 			 * and doesn't know layer 2 has already connected
 			 */
 			nb->state = X25_LINK_STATE_3;
 			x25_transmit_restart_confirmation(nb);
 			break;
 		case X25_LINK_STATE_2:
 			x25_stop_t20timer(nb);
 			nb->state = X25_LINK_STATE_3;
 			break;
 		case X25_LINK_STATE_3:
 			/* clear existing virtual calls */
 			x25_kill_by_neigh(nb);

 			x25_transmit_restart_confirmation(nb);
 			break;
 		}
 		break;

 	case X25_RESTART_CONFIRMATION:
 		switch (nb->state) {
 		case X25_LINK_STATE_2:
 			x25_stop_t20timer(nb);
 			nb->state = X25_LINK_STATE_3;
 			break;
 		case X25_LINK_STATE_3:
 			/* clear existing virtual calls */
 			x25_kill_by_neigh(nb);

 			x25_transmit_restart_request(nb);
 			nb->state = X25_LINK_STATE_2;
 			x25_start_t20timer(nb);
 			break;
 		}
 		break;

 	case X25_DIAGNOSTIC:
 		if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4))
 			break;

 		pr_warn("diagnostic #%d - %02X %02X %02X\n",
 		       skb->data[3], skb->data[4],
 		       skb->data[5], skb->data[6]);
 		break;

 	default:
 		pr_warn("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:
 	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;
 	skb_queue_purge(&nb->queue);
 	x25_stop_t20timer(nb);

 	/* 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);
 	timer_setup(&nb->t20timer, x25_t20timer_expiry, 0);

 	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;
 	refcount_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)
 {
 	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;

 	read_lock_bh(&x25_neigh_list_lock);
 	list_for_each_entry(nb, &x25_neigh_list, 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) {
 		read_lock_bh(&x25_neigh_list_lock);
 		x25_subscr.extended	     = nb->extended;
 		x25_subscr.global_facil_mask = nb->global_facil_mask;
 		read_unlock_bh(&x25_neigh_list_lock);
 		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;
 			write_lock_bh(&x25_neigh_list_lock);
 			nb->extended	     = x25_subscr.extended;
 			nb->global_facil_mask = x25_subscr.global_facil_mask;
 			write_unlock_bh(&x25_neigh_list_lock);
 		}
 	}
 	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) {
 		struct net_device *dev;

 		nb = list_entry(entry, struct x25_neigh, node);
 		dev = nb->dev;
 		__x25_remove_neigh(nb);
 		dev_put(dev);
 	}
 	write_unlock_bh(&x25_neigh_list_lock);
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* 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
	*
	* 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.
	*/

	#define pr_fmt(fmt) "X25: " fmt

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

	LIST_HEAD(x25_neigh_list);
	DEFINE_RWLOCK(x25_neigh_list_lock);

	static void x25_t20timer_expiry(struct timer_list *);

	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(struct timer_list *t)
	{
	struct x25_neigh *nb = from_timer(nb, t, t20timer);

	x25_transmit_restart_request(nb);

	x25_start_t20timer(nb);
	}

	static inline void x25_stop_t20timer(struct x25_neigh *nb)
	{
	del_timer(&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;

	switch (frametype) {
	case X25_RESTART_REQUEST:
	switch (nb->state) {
	case X25_LINK_STATE_0:
	/* This can happen when the x25 module just gets loaded
	* and doesn't know layer 2 has already connected
	*/
	nb->state = X25_LINK_STATE_3;
	x25_transmit_restart_confirmation(nb);
	break;
	case X25_LINK_STATE_2:
	x25_stop_t20timer(nb);
	nb->state = X25_LINK_STATE_3;
	break;
	case X25_LINK_STATE_3:
	/* clear existing virtual calls */
	x25_kill_by_neigh(nb);

	x25_transmit_restart_confirmation(nb);
	break;
	}
	break;

	case X25_RESTART_CONFIRMATION:
	switch (nb->state) {
	case X25_LINK_STATE_2:
	x25_stop_t20timer(nb);
	nb->state = X25_LINK_STATE_3;
	break;
	case X25_LINK_STATE_3:
	/* clear existing virtual calls */
	x25_kill_by_neigh(nb);

	x25_transmit_restart_request(nb);
	nb->state = X25_LINK_STATE_2;
	x25_start_t20timer(nb);
	break;
	}
	break;

	case X25_DIAGNOSTIC:
	if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4))
	break;

	pr_warn("diagnostic #%d - %02X %02X %02X\n",
	skb->data[3], skb->data[4],
	skb->data[5], skb->data[6]);
	break;

	default:
	pr_warn("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:
	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;
	skb_queue_purge(&nb->queue);
	x25_stop_t20timer(nb);

	/* 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);
	timer_setup(&nb->t20timer, x25_t20timer_expiry, 0);

	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;
	refcount_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)
	{
	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;

	read_lock_bh(&x25_neigh_list_lock);
	list_for_each_entry(nb, &x25_neigh_list, 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) {
	read_lock_bh(&x25_neigh_list_lock);
	x25_subscr.extended = nb->extended;
	x25_subscr.global_facil_mask = nb->global_facil_mask;
	read_unlock_bh(&x25_neigh_list_lock);
	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;
	write_lock_bh(&x25_neigh_list_lock);
	nb->extended = x25_subscr.extended;
	nb->global_facil_mask = x25_subscr.global_facil_mask;
	write_unlock_bh(&x25_neigh_list_lock);
	}
	}
	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) {
	struct net_device *dev;

	nb = list_entry(entry, struct x25_neigh, node);
	dev = nb->dev;
	__x25_remove_neigh(nb);
	dev_put(dev);
	}
	write_unlock_bh(&x25_neigh_list_lock);
	}