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

  /*

   *
   * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   * Copyright Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
   * Copyright Tomi Manninen OH2BNS (oh2bns@sral.fi)
   */
  #include <linux/errno.h>
  #include <linux/types.h>
  #include <linux/socket.h>
  #include <linux/in.h>
  #include <linux/kernel.h>

  #include <linux/timer.h>
  #include <linux/string.h>
  #include <linux/sockios.h>
  #include <linux/net.h>

  #include <linux/slab.h>

  #include <net/ax25.h>
  #include <linux/inet.h>
  #include <linux/netdevice.h>
  #include <net/arp.h>
  #include <linux/if_arp.h>
  #include <linux/skbuff.h>
  #include <net/sock.h>

  #include <linux/uaccess.h>

  #include <linux/fcntl.h>
  #include <linux/termios.h>	/* For TIOCINQ/OUTQ */
  #include <linux/mm.h>
  #include <linux/interrupt.h>
  #include <linux/notifier.h>

  #include <linux/init.h>
  #include <linux/spinlock.h>
  #include <net/netrom.h>
  #include <linux/seq_file.h>

  #include <linux/export.h>

  
  static unsigned int nr_neigh_no = 1;
  
  static HLIST_HEAD(nr_node_list);
  static DEFINE_SPINLOCK(nr_node_list_lock);
  static HLIST_HEAD(nr_neigh_list);
  static DEFINE_SPINLOCK(nr_neigh_list_lock);
  
  static struct nr_node *nr_node_get(ax25_address *callsign)
  {
  	struct nr_node *found = NULL;
  	struct nr_node *nr_node;

  
  	spin_lock_bh(&nr_node_list_lock);

  	nr_node_for_each(nr_node, &nr_node_list)

  		if (ax25cmp(callsign, &nr_node->callsign) == 0) {
  			nr_node_hold(nr_node);
  			found = nr_node;
  			break;
  		}
  	spin_unlock_bh(&nr_node_list_lock);
  	return found;
  }
  
  static struct nr_neigh *nr_neigh_get_dev(ax25_address *callsign,
  					 struct net_device *dev)
  {
  	struct nr_neigh *found = NULL;
  	struct nr_neigh *nr_neigh;

  
  	spin_lock_bh(&nr_neigh_list_lock);

  	nr_neigh_for_each(nr_neigh, &nr_neigh_list)

  		if (ax25cmp(callsign, &nr_neigh->callsign) == 0 &&
  		    nr_neigh->dev == dev) {
  			nr_neigh_hold(nr_neigh);
  			found = nr_neigh;
  			break;
  		}
  	spin_unlock_bh(&nr_neigh_list_lock);
  	return found;
  }
  
  static void nr_remove_neigh(struct nr_neigh *);

  /*      re-sort the routes in quality order.    */
  static void re_sort_routes(struct nr_node *nr_node, int x, int y)
  {
  	if (nr_node->routes[y].quality > nr_node->routes[x].quality) {
  		if (nr_node->which == x)
  			nr_node->which = y;
  		else if (nr_node->which == y)
  			nr_node->which = x;
  
  		swap(nr_node->routes[x], nr_node->routes[y]);
  	}
  }

  /*
   *	Add a new route to a node, and in the process add the node and the
   *	neighbour if it is new.
   */

  static int __must_check nr_add_node(ax25_address *nr, const char *mnemonic,
  	ax25_address *ax25, ax25_digi *ax25_digi, struct net_device *dev,
  	int quality, int obs_count)

  {
  	struct nr_node  *nr_node;
  	struct nr_neigh *nr_neigh;

  	int i, found;
  	struct net_device *odev;
  
  	if ((odev=nr_dev_get(nr)) != NULL) {	/* Can't add routes to ourself */
  		dev_put(odev);
  		return -EINVAL;
  	}
  
  	nr_node = nr_node_get(nr);
  
  	nr_neigh = nr_neigh_get_dev(ax25, dev);
  
  	/*
  	 * The L2 link to a neighbour has failed in the past
  	 * and now a frame comes from this neighbour. We assume
  	 * it was a temporary trouble with the link and reset the
  	 * routes now (and not wait for a node broadcast).
  	 */
  	if (nr_neigh != NULL && nr_neigh->failed != 0 && quality == 0) {
  		struct nr_node *nr_nodet;

  
  		spin_lock_bh(&nr_node_list_lock);

  		nr_node_for_each(nr_nodet, &nr_node_list) {

  			nr_node_lock(nr_nodet);
  			for (i = 0; i < nr_nodet->count; i++)
  				if (nr_nodet->routes[i].neighbour == nr_neigh)
  					if (i < nr_nodet->which)
  						nr_nodet->which = i;
  			nr_node_unlock(nr_nodet);
  		}
  		spin_unlock_bh(&nr_node_list_lock);
  	}
  
  	if (nr_neigh != NULL)
  		nr_neigh->failed = 0;
  
  	if (quality == 0 && nr_neigh != NULL && nr_node != NULL) {
  		nr_neigh_put(nr_neigh);
  		nr_node_put(nr_node);
  		return 0;
  	}
  
  	if (nr_neigh == NULL) {
  		if ((nr_neigh = kmalloc(sizeof(*nr_neigh), GFP_ATOMIC)) == NULL) {
  			if (nr_node)
  				nr_node_put(nr_node);
  			return -ENOMEM;
  		}
  
  		nr_neigh->callsign = *ax25;
  		nr_neigh->digipeat = NULL;
  		nr_neigh->ax25     = NULL;
  		nr_neigh->dev      = dev;
  		nr_neigh->quality  = sysctl_netrom_default_path_quality;
  		nr_neigh->locked   = 0;
  		nr_neigh->count    = 0;
  		nr_neigh->number   = nr_neigh_no++;
  		nr_neigh->failed   = 0;

  		refcount_set(&nr_neigh->refcount, 1);

  
  		if (ax25_digi != NULL && ax25_digi->ndigi > 0) {

  			nr_neigh->digipeat = kmemdup(ax25_digi,
  						     sizeof(*ax25_digi),
  						     GFP_KERNEL);
  			if (nr_neigh->digipeat == NULL) {

  				kfree(nr_neigh);
  				if (nr_node)
  					nr_node_put(nr_node);
  				return -ENOMEM;
  			}

  		}
  
  		spin_lock_bh(&nr_neigh_list_lock);
  		hlist_add_head(&nr_neigh->neigh_node, &nr_neigh_list);
  		nr_neigh_hold(nr_neigh);
  		spin_unlock_bh(&nr_neigh_list_lock);
  	}
  
  	if (quality != 0 && ax25cmp(nr, ax25) == 0 && !nr_neigh->locked)
  		nr_neigh->quality = quality;
  
  	if (nr_node == NULL) {
  		if ((nr_node = kmalloc(sizeof(*nr_node), GFP_ATOMIC)) == NULL) {
  			if (nr_neigh)
  				nr_neigh_put(nr_neigh);
  			return -ENOMEM;
  		}
  
  		nr_node->callsign = *nr;
  		strcpy(nr_node->mnemonic, mnemonic);
  
  		nr_node->which = 0;
  		nr_node->count = 1;

  		refcount_set(&nr_node->refcount, 1);

  		spin_lock_init(&nr_node->node_lock);
  
  		nr_node->routes[0].quality   = quality;
  		nr_node->routes[0].obs_count = obs_count;
  		nr_node->routes[0].neighbour = nr_neigh;
  
  		nr_neigh_hold(nr_neigh);
  		nr_neigh->count++;
  
  		spin_lock_bh(&nr_node_list_lock);
  		hlist_add_head(&nr_node->node_node, &nr_node_list);
  		/* refcount initialized at 1 */
  		spin_unlock_bh(&nr_node_list_lock);

  		nr_neigh_put(nr_neigh);

  		return 0;
  	}
  	nr_node_lock(nr_node);
  
  	if (quality != 0)
  		strcpy(nr_node->mnemonic, mnemonic);
  
  	for (found = 0, i = 0; i < nr_node->count; i++) {
  		if (nr_node->routes[i].neighbour == nr_neigh) {
  			nr_node->routes[i].quality   = quality;
  			nr_node->routes[i].obs_count = obs_count;
  			found = 1;
  			break;
  		}
  	}
  
  	if (!found) {
  		/* We have space at the bottom, slot it in */
  		if (nr_node->count < 3) {
  			nr_node->routes[2] = nr_node->routes[1];
  			nr_node->routes[1] = nr_node->routes[0];
  
  			nr_node->routes[0].quality   = quality;
  			nr_node->routes[0].obs_count = obs_count;
  			nr_node->routes[0].neighbour = nr_neigh;
  
  			nr_node->which++;
  			nr_node->count++;
  			nr_neigh_hold(nr_neigh);
  			nr_neigh->count++;
  		} else {
  			/* It must be better than the worst */
  			if (quality > nr_node->routes[2].quality) {
  				nr_node->routes[2].neighbour->count--;
  				nr_neigh_put(nr_node->routes[2].neighbour);
  
  				if (nr_node->routes[2].neighbour->count == 0 && !nr_node->routes[2].neighbour->locked)
  					nr_remove_neigh(nr_node->routes[2].neighbour);
  
  				nr_node->routes[2].quality   = quality;
  				nr_node->routes[2].obs_count = obs_count;
  				nr_node->routes[2].neighbour = nr_neigh;
  
  				nr_neigh_hold(nr_neigh);
  				nr_neigh->count++;
  			}
  		}
  	}
  
  	/* Now re-sort the routes in quality order */
  	switch (nr_node->count) {
  	case 3:

  		re_sort_routes(nr_node, 0, 1);
  		re_sort_routes(nr_node, 1, 2);

  		fallthrough;

  	case 2:

  		re_sort_routes(nr_node, 0, 1);

  	case 1:
  		break;
  	}
  
  	for (i = 0; i < nr_node->count; i++) {
  		if (nr_node->routes[i].neighbour == nr_neigh) {
  			if (i < nr_node->which)
  				nr_node->which = i;
  			break;
  		}
  	}
  
  	nr_neigh_put(nr_neigh);
  	nr_node_unlock(nr_node);
  	nr_node_put(nr_node);
  	return 0;
  }
  
  static inline void __nr_remove_node(struct nr_node *nr_node)
  {
  	hlist_del_init(&nr_node->node_node);
  	nr_node_put(nr_node);
  }
  
  #define nr_remove_node_locked(__node) \
  	__nr_remove_node(__node)
  
  static void nr_remove_node(struct nr_node *nr_node)
  {
  	spin_lock_bh(&nr_node_list_lock);
  	__nr_remove_node(nr_node);
  	spin_unlock_bh(&nr_node_list_lock);
  }
  
  static inline void __nr_remove_neigh(struct nr_neigh *nr_neigh)
  {
  	hlist_del_init(&nr_neigh->neigh_node);
  	nr_neigh_put(nr_neigh);
  }
  
  #define nr_remove_neigh_locked(__neigh) \
  	__nr_remove_neigh(__neigh)
  
  static void nr_remove_neigh(struct nr_neigh *nr_neigh)
  {
  	spin_lock_bh(&nr_neigh_list_lock);
  	__nr_remove_neigh(nr_neigh);
  	spin_unlock_bh(&nr_neigh_list_lock);
  }
  
  /*
   *	"Delete" a node. Strictly speaking remove a route to a node. The node
   *	is only deleted if no routes are left to it.
   */
  static int nr_del_node(ax25_address *callsign, ax25_address *neighbour, struct net_device *dev)
  {
  	struct nr_node  *nr_node;
  	struct nr_neigh *nr_neigh;
  	int i;
  
  	nr_node = nr_node_get(callsign);
  
  	if (nr_node == NULL)
  		return -EINVAL;
  
  	nr_neigh = nr_neigh_get_dev(neighbour, dev);
  
  	if (nr_neigh == NULL) {
  		nr_node_put(nr_node);
  		return -EINVAL;
  	}
  
  	nr_node_lock(nr_node);
  	for (i = 0; i < nr_node->count; i++) {
  		if (nr_node->routes[i].neighbour == nr_neigh) {
  			nr_neigh->count--;
  			nr_neigh_put(nr_neigh);
  
  			if (nr_neigh->count == 0 && !nr_neigh->locked)
  				nr_remove_neigh(nr_neigh);
  			nr_neigh_put(nr_neigh);
  
  			nr_node->count--;
  
  			if (nr_node->count == 0) {
  				nr_remove_node(nr_node);
  			} else {
  				switch (i) {
  				case 0:
  					nr_node->routes[0] = nr_node->routes[1];

  					fallthrough;

  				case 1:
  					nr_node->routes[1] = nr_node->routes[2];
  				case 2:
  					break;
  				}
  				nr_node_put(nr_node);
  			}
  			nr_node_unlock(nr_node);
  
  			return 0;
  		}
  	}
  	nr_neigh_put(nr_neigh);
  	nr_node_unlock(nr_node);
  	nr_node_put(nr_node);
  
  	return -EINVAL;
  }
  
  /*
   *	Lock a neighbour with a quality.
   */

  static int __must_check nr_add_neigh(ax25_address *callsign,
  	ax25_digi *ax25_digi, struct net_device *dev, unsigned int quality)

  {
  	struct nr_neigh *nr_neigh;
  
  	nr_neigh = nr_neigh_get_dev(callsign, dev);
  	if (nr_neigh) {
  		nr_neigh->quality = quality;
  		nr_neigh->locked  = 1;
  		nr_neigh_put(nr_neigh);
  		return 0;
  	}
  
  	if ((nr_neigh = kmalloc(sizeof(*nr_neigh), GFP_ATOMIC)) == NULL)
  		return -ENOMEM;
  
  	nr_neigh->callsign = *callsign;
  	nr_neigh->digipeat = NULL;
  	nr_neigh->ax25     = NULL;
  	nr_neigh->dev      = dev;
  	nr_neigh->quality  = quality;
  	nr_neigh->locked   = 1;
  	nr_neigh->count    = 0;
  	nr_neigh->number   = nr_neigh_no++;
  	nr_neigh->failed   = 0;

  	refcount_set(&nr_neigh->refcount, 1);

  
  	if (ax25_digi != NULL && ax25_digi->ndigi > 0) {

  		nr_neigh->digipeat = kmemdup(ax25_digi, sizeof(*ax25_digi),
  					     GFP_KERNEL);
  		if (nr_neigh->digipeat == NULL) {

  			kfree(nr_neigh);
  			return -ENOMEM;
  		}

  	}
  
  	spin_lock_bh(&nr_neigh_list_lock);
  	hlist_add_head(&nr_neigh->neigh_node, &nr_neigh_list);
  	/* refcount is initialized at 1 */
  	spin_unlock_bh(&nr_neigh_list_lock);
  
  	return 0;
  }
  
  /*
   *	"Delete" a neighbour. The neighbour is only removed if the number
   *	of nodes that may use it is zero.
   */
  static int nr_del_neigh(ax25_address *callsign, struct net_device *dev, unsigned int quality)
  {
  	struct nr_neigh *nr_neigh;
  
  	nr_neigh = nr_neigh_get_dev(callsign, dev);
  
  	if (nr_neigh == NULL) return -EINVAL;
  
  	nr_neigh->quality = quality;
  	nr_neigh->locked  = 0;
  
  	if (nr_neigh->count == 0)
  		nr_remove_neigh(nr_neigh);
  	nr_neigh_put(nr_neigh);
  
  	return 0;
  }
  
  /*
   *	Decrement the obsolescence count by one. If a route is reduced to a
   *	count of zero, remove it. Also remove any unlocked neighbours with
   *	zero nodes routing via it.
   */
  static int nr_dec_obs(void)
  {
  	struct nr_neigh *nr_neigh;
  	struct nr_node  *s;

  	struct hlist_node *nodet;

  	int i;
  
  	spin_lock_bh(&nr_node_list_lock);

  	nr_node_for_each_safe(s, nodet, &nr_node_list) {

  		nr_node_lock(s);
  		for (i = 0; i < s->count; i++) {
  			switch (s->routes[i].obs_count) {
  			case 0:		/* A locked entry */
  				break;
  
  			case 1:		/* From 1 -> 0 */
  				nr_neigh = s->routes[i].neighbour;
  
  				nr_neigh->count--;
  				nr_neigh_put(nr_neigh);
  
  				if (nr_neigh->count == 0 && !nr_neigh->locked)
  					nr_remove_neigh(nr_neigh);
  
  				s->count--;
  
  				switch (i) {

  				case 0:
  					s->routes[0] = s->routes[1];

  					fallthrough;

  				case 1:
  					s->routes[1] = s->routes[2];
  				case 2:
  					break;

  				}
  				break;
  
  			default:
  				s->routes[i].obs_count--;
  				break;
  
  			}
  		}
  
  		if (s->count <= 0)
  			nr_remove_node_locked(s);
  		nr_node_unlock(s);
  	}
  	spin_unlock_bh(&nr_node_list_lock);
  
  	return 0;
  }
  
  /*
   *	A device has been removed. Remove its routes and neighbours.
   */
  void nr_rt_device_down(struct net_device *dev)
  {
  	struct nr_neigh *s;

  	struct hlist_node *nodet, *node2t;

  	struct nr_node  *t;
  	int i;
  
  	spin_lock_bh(&nr_neigh_list_lock);

  	nr_neigh_for_each_safe(s, nodet, &nr_neigh_list) {

  		if (s->dev == dev) {
  			spin_lock_bh(&nr_node_list_lock);

  			nr_node_for_each_safe(t, node2t, &nr_node_list) {

  				nr_node_lock(t);
  				for (i = 0; i < t->count; i++) {
  					if (t->routes[i].neighbour == s) {
  						t->count--;
  
  						switch (i) {
  						case 0:
  							t->routes[0] = t->routes[1];

  							fallthrough;

  						case 1:
  							t->routes[1] = t->routes[2];
  						case 2:
  							break;
  						}
  					}
  				}
  
  				if (t->count <= 0)
  					nr_remove_node_locked(t);
  				nr_node_unlock(t);
  			}
  			spin_unlock_bh(&nr_node_list_lock);
  
  			nr_remove_neigh_locked(s);
  		}
  	}
  	spin_unlock_bh(&nr_neigh_list_lock);
  }
  
  /*
   *	Check that the device given is a valid AX.25 interface that is "up".
   *	Or a valid ethernet interface with an AX.25 callsign binding.
   */
  static struct net_device *nr_ax25_dev_get(char *devname)
  {
  	struct net_device *dev;

  	if ((dev = dev_get_by_name(&init_net, devname)) == NULL)

  		return NULL;
  
  	if ((dev->flags & IFF_UP) && dev->type == ARPHRD_AX25)
  		return dev;
  
  	dev_put(dev);
  	return NULL;
  }
  
  /*
   *	Find the first active NET/ROM device, usually "nr0".
   */
  struct net_device *nr_dev_first(void)
  {
  	struct net_device *dev, *first = NULL;

  	rcu_read_lock();
  	for_each_netdev_rcu(&init_net, dev) {

  		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM)
  			if (first == NULL || strncmp(dev->name, first->name, 3) < 0)
  				first = dev;
  	}
  	if (first)
  		dev_hold(first);

  	rcu_read_unlock();

  
  	return first;
  }
  
  /*
   *	Find the NET/ROM device for the given callsign.
   */
  struct net_device *nr_dev_get(ax25_address *addr)
  {
  	struct net_device *dev;

  	rcu_read_lock();
  	for_each_netdev_rcu(&init_net, dev) {
  		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM &&
  		    ax25cmp(addr, (ax25_address *)dev->dev_addr) == 0) {

  			dev_hold(dev);
  			goto out;
  		}
  	}

  	dev = NULL;

  out:

  	rcu_read_unlock();

  	return dev;
  }

  static ax25_digi *nr_call_to_digi(ax25_digi *digi, int ndigis,
  	ax25_address *digipeaters)

  {

  	int i;
  
  	if (ndigis == 0)
  		return NULL;
  
  	for (i = 0; i < ndigis; i++) {

  		digi->calls[i]    = digipeaters[i];
  		digi->repeated[i] = 0;

  	}

  	digi->ndigi      = ndigis;
  	digi->lastrepeat = -1;

  	return digi;

  }
  
  /*
   *	Handle the ioctls that control the routing functions.
   */
  int nr_rt_ioctl(unsigned int cmd, void __user *arg)
  {
  	struct nr_route_struct nr_route;
  	struct net_device *dev;

  	ax25_digi digi;

  	int ret;
  
  	switch (cmd) {
  	case SIOCADDRT:
  		if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct)))
  			return -EFAULT;

  		if (nr_route.ndigis > AX25_MAX_DIGIS)

  			return -EINVAL;

  		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)

  			return -EINVAL;

  		switch (nr_route.type) {
  		case NETROM_NODE:

  			if (strnlen(nr_route.mnemonic, 7) == 7) {
  				ret = -EINVAL;
  				break;
  			}

  			ret = nr_add_node(&nr_route.callsign,
  				nr_route.mnemonic,
  				&nr_route.neighbour,

  				nr_call_to_digi(&digi, nr_route.ndigis,
  						nr_route.digipeaters),

  				dev, nr_route.quality,
  				nr_route.obs_count);
  			break;
  		case NETROM_NEIGH:
  			ret = nr_add_neigh(&nr_route.callsign,

  				nr_call_to_digi(&digi, nr_route.ndigis,
  						nr_route.digipeaters),

  				dev, nr_route.quality);
  			break;
  		default:
  			ret = -EINVAL;
  		}
  		dev_put(dev);
  		return ret;
  
  	case SIOCDELRT:
  		if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct)))
  			return -EFAULT;
  		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)
  			return -EINVAL;
  		switch (nr_route.type) {
  		case NETROM_NODE:
  			ret = nr_del_node(&nr_route.callsign,
  				&nr_route.neighbour, dev);
  			break;
  		case NETROM_NEIGH:
  			ret = nr_del_neigh(&nr_route.callsign,
  				dev, nr_route.quality);
  			break;
  		default:
  			ret = -EINVAL;
  		}
  		dev_put(dev);
  		return ret;
  
  	case SIOCNRDECOBS:
  		return nr_dec_obs();
  
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  /*
   * 	A level 2 link has timed out, therefore it appears to be a poor link,
   *	then don't use that neighbour until it is reset.
   */
  void nr_link_failed(ax25_cb *ax25, int reason)
  {
  	struct nr_neigh *s, *nr_neigh = NULL;

  	struct nr_node  *nr_node = NULL;
  
  	spin_lock_bh(&nr_neigh_list_lock);

  	nr_neigh_for_each(s, &nr_neigh_list) {

  		if (s->ax25 == ax25) {
  			nr_neigh_hold(s);
  			nr_neigh = s;
  			break;
  		}

  	}

  	spin_unlock_bh(&nr_neigh_list_lock);

  	if (nr_neigh == NULL)
  		return;

  
  	nr_neigh->ax25 = NULL;
  	ax25_cb_put(ax25);
  
  	if (++nr_neigh->failed < sysctl_netrom_link_fails_count) {
  		nr_neigh_put(nr_neigh);
  		return;
  	}
  	spin_lock_bh(&nr_node_list_lock);

  	nr_node_for_each(nr_node, &nr_node_list) {

  		nr_node_lock(nr_node);

  		if (nr_node->which < nr_node->count &&
  		    nr_node->routes[nr_node->which].neighbour == nr_neigh)

  			nr_node->which++;
  		nr_node_unlock(nr_node);

  	}

  	spin_unlock_bh(&nr_node_list_lock);
  	nr_neigh_put(nr_neigh);
  }
  
  /*
   *	Route a frame to an appropriate AX.25 connection. A NULL ax25_cb
   *	indicates an internally generated frame.
   */
  int nr_route_frame(struct sk_buff *skb, ax25_cb *ax25)
  {
  	ax25_address *nr_src, *nr_dest;
  	struct nr_neigh *nr_neigh;
  	struct nr_node  *nr_node;
  	struct net_device *dev;
  	unsigned char *dptr;
  	ax25_cb *ax25s;
  	int ret;
  	struct sk_buff *skbn;
  
  
  	nr_src  = (ax25_address *)(skb->data + 0);
  	nr_dest = (ax25_address *)(skb->data + 7);

  	if (ax25 != NULL) {
  		ret = nr_add_node(nr_src, "", &ax25->dest_addr, ax25->digipeat,

  				  ax25->ax25_dev->dev, 0,
  				  sysctl_netrom_obsolescence_count_initialiser);

  		if (ret)
  			return ret;
  	}

  
  	if ((dev = nr_dev_get(nr_dest)) != NULL) {	/* Its for me */
  		if (ax25 == NULL)			/* Its from me */
  			ret = nr_loopback_queue(skb);
  		else
  			ret = nr_rx_frame(skb, dev);
  		dev_put(dev);
  		return ret;
  	}
  
  	if (!sysctl_netrom_routing_control && ax25 != NULL)
  		return 0;
  
  	/* Its Time-To-Live has expired */
  	if (skb->data[14] == 1) {
  		return 0;
  	}
  
  	nr_node = nr_node_get(nr_dest);
  	if (nr_node == NULL)
  		return 0;
  	nr_node_lock(nr_node);
  
  	if (nr_node->which >= nr_node->count) {
  		nr_node_unlock(nr_node);
  		nr_node_put(nr_node);
  		return 0;
  	}
  
  	nr_neigh = nr_node->routes[nr_node->which].neighbour;
  
  	if ((dev = nr_dev_first()) == NULL) {
  		nr_node_unlock(nr_node);
  		nr_node_put(nr_node);
  		return 0;
  	}
  
  	/* We are going to change the netrom headers so we should get our
  	   own skb, we also did not know until now how much header space
  	   we had to reserve... - RXQ */
  	if ((skbn=skb_copy_expand(skb, dev->hard_header_len, 0, GFP_ATOMIC)) == NULL) {
  		nr_node_unlock(nr_node);
  		nr_node_put(nr_node);
  		dev_put(dev);
  		return 0;
  	}
  	kfree_skb(skb);
  	skb=skbn;
  	skb->data[14]--;
  
  	dptr  = skb_push(skb, 1);
  	*dptr = AX25_P_NETROM;

  	ax25s = nr_neigh->ax25;
  	nr_neigh->ax25 = ax25_send_frame(skb, 256,
  					 (ax25_address *)dev->dev_addr,
  					 &nr_neigh->callsign,
  					 nr_neigh->digipeat, nr_neigh->dev);
  	if (ax25s)

  		ax25_cb_put(ax25s);

  
  	dev_put(dev);
  	ret = (nr_neigh->ax25 != NULL);
  	nr_node_unlock(nr_node);
  	nr_node_put(nr_node);

  	return ret;
  }
  
  #ifdef CONFIG_PROC_FS
  
  static void *nr_node_start(struct seq_file *seq, loff_t *pos)

  	__acquires(&nr_node_list_lock)

  {

  	spin_lock_bh(&nr_node_list_lock);

  	return seq_hlist_start_head(&nr_node_list, *pos);

  }
  
  static void *nr_node_next(struct seq_file *seq, void *v, loff_t *pos)
  {

  	return seq_hlist_next(v, &nr_node_list, pos);

  }
  
  static void nr_node_stop(struct seq_file *seq, void *v)

  	__releases(&nr_node_list_lock)

  {
  	spin_unlock_bh(&nr_node_list_lock);
  }
  
  static int nr_node_show(struct seq_file *seq, void *v)
  {

  	char buf[11];

  	int i;
  
  	if (v == SEQ_START_TOKEN)
  		seq_puts(seq,
  			 "callsign  mnemonic w n qual obs neigh qual obs neigh qual obs neigh
  ");
  	else {

  		struct nr_node *nr_node = hlist_entry(v, struct nr_node,
  						      node_node);

  		nr_node_lock(nr_node);
  		seq_printf(seq, "%-9s %-7s  %d %d",

  			ax2asc(buf, &nr_node->callsign),

  			(nr_node->mnemonic[0] == '\0') ? "*" : nr_node->mnemonic,
  			nr_node->which + 1,
  			nr_node->count);
  
  		for (i = 0; i < nr_node->count; i++) {
  			seq_printf(seq, "  %3d   %d %05d",
  				nr_node->routes[i].quality,
  				nr_node->routes[i].obs_count,
  				nr_node->routes[i].neighbour->number);
  		}
  		nr_node_unlock(nr_node);
  
  		seq_puts(seq, "
  ");
  	}
  	return 0;
  }

  const struct seq_operations nr_node_seqops = {

  	.start = nr_node_start,
  	.next = nr_node_next,
  	.stop = nr_node_stop,
  	.show = nr_node_show,
  };

  static void *nr_neigh_start(struct seq_file *seq, loff_t *pos)

  	__acquires(&nr_neigh_list_lock)

  {

  	spin_lock_bh(&nr_neigh_list_lock);

  	return seq_hlist_start_head(&nr_neigh_list, *pos);

  }
  
  static void *nr_neigh_next(struct seq_file *seq, void *v, loff_t *pos)
  {

  	return seq_hlist_next(v, &nr_neigh_list, pos);

  }
  
  static void nr_neigh_stop(struct seq_file *seq, void *v)

  	__releases(&nr_neigh_list_lock)

  {
  	spin_unlock_bh(&nr_neigh_list_lock);
  }
  
  static int nr_neigh_show(struct seq_file *seq, void *v)
  {

  	char buf[11];

  	int i;
  
  	if (v == SEQ_START_TOKEN)
  		seq_puts(seq, "addr  callsign  dev  qual lock count failed digipeaters
  ");
  	else {

  		struct nr_neigh *nr_neigh;

  		nr_neigh = hlist_entry(v, struct nr_neigh, neigh_node);

  		seq_printf(seq, "%05d %-9s %-4s  %3d    %d   %3d    %3d",
  			nr_neigh->number,

  			ax2asc(buf, &nr_neigh->callsign),

  			nr_neigh->dev ? nr_neigh->dev->name : "???",
  			nr_neigh->quality,
  			nr_neigh->locked,
  			nr_neigh->count,
  			nr_neigh->failed);
  
  		if (nr_neigh->digipeat != NULL) {
  			for (i = 0; i < nr_neigh->digipeat->ndigi; i++)

  				seq_printf(seq, " %s",

  					   ax2asc(buf, &nr_neigh->digipeat->calls[i]));

  		}
  
  		seq_puts(seq, "
  ");
  	}
  	return 0;
  }

  const struct seq_operations nr_neigh_seqops = {

  	.start = nr_neigh_start,
  	.next = nr_neigh_next,
  	.stop = nr_neigh_stop,
  	.show = nr_neigh_show,
  };

  #endif
  
  /*
   *	Free all memory associated with the nodes and routes lists.
   */

  void nr_rt_free(void)

  {
  	struct nr_neigh *s = NULL;
  	struct nr_node  *t = NULL;

  	struct hlist_node *nodet;

  
  	spin_lock_bh(&nr_neigh_list_lock);
  	spin_lock_bh(&nr_node_list_lock);

  	nr_node_for_each_safe(t, nodet, &nr_node_list) {

  		nr_node_lock(t);
  		nr_remove_node_locked(t);
  		nr_node_unlock(t);
  	}

  	nr_neigh_for_each_safe(s, nodet, &nr_neigh_list) {

  		while(s->count) {
  			s->count--;
  			nr_neigh_put(s);
  		}
  		nr_remove_neigh_locked(s);
  	}
  	spin_unlock_bh(&nr_node_list_lock);
  	spin_unlock_bh(&nr_neigh_list_lock);
  }