xref: /linux/net/netrom/nr_route.c (revision 5e8c0fb6a95728b852d56c0a9244425d474670c0)
1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License as published by
4  * the Free Software Foundation; either version 2 of the License, or
5  * (at your option) any later version.
6  *
7  * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
8  * Copyright Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
9  * Copyright Tomi Manninen OH2BNS (oh2bns@sral.fi)
10  */
11 #include <linux/errno.h>
12 #include <linux/types.h>
13 #include <linux/socket.h>
14 #include <linux/in.h>
15 #include <linux/kernel.h>
16 #include <linux/timer.h>
17 #include <linux/string.h>
18 #include <linux/sockios.h>
19 #include <linux/net.h>
20 #include <linux/slab.h>
21 #include <net/ax25.h>
22 #include <linux/inet.h>
23 #include <linux/netdevice.h>
24 #include <net/arp.h>
25 #include <linux/if_arp.h>
26 #include <linux/skbuff.h>
27 #include <net/sock.h>
28 #include <linux/uaccess.h>
29 #include <linux/fcntl.h>
30 #include <linux/termios.h>	/* For TIOCINQ/OUTQ */
31 #include <linux/mm.h>
32 #include <linux/interrupt.h>
33 #include <linux/notifier.h>
34 #include <linux/netfilter.h>
35 #include <linux/init.h>
36 #include <linux/spinlock.h>
37 #include <net/netrom.h>
38 #include <linux/seq_file.h>
39 #include <linux/export.h>
40 
41 static unsigned int nr_neigh_no = 1;
42 
43 static HLIST_HEAD(nr_node_list);
44 static DEFINE_SPINLOCK(nr_node_list_lock);
45 static HLIST_HEAD(nr_neigh_list);
46 static DEFINE_SPINLOCK(nr_neigh_list_lock);
47 
48 static struct nr_node *nr_node_get(ax25_address *callsign)
49 {
50 	struct nr_node *found = NULL;
51 	struct nr_node *nr_node;
52 
53 	spin_lock_bh(&nr_node_list_lock);
54 	nr_node_for_each(nr_node, &nr_node_list)
55 		if (ax25cmp(callsign, &nr_node->callsign) == 0) {
56 			nr_node_hold(nr_node);
57 			found = nr_node;
58 			break;
59 		}
60 	spin_unlock_bh(&nr_node_list_lock);
61 	return found;
62 }
63 
64 static struct nr_neigh *nr_neigh_get_dev(ax25_address *callsign,
65 					 struct net_device *dev)
66 {
67 	struct nr_neigh *found = NULL;
68 	struct nr_neigh *nr_neigh;
69 
70 	spin_lock_bh(&nr_neigh_list_lock);
71 	nr_neigh_for_each(nr_neigh, &nr_neigh_list)
72 		if (ax25cmp(callsign, &nr_neigh->callsign) == 0 &&
73 		    nr_neigh->dev == dev) {
74 			nr_neigh_hold(nr_neigh);
75 			found = nr_neigh;
76 			break;
77 		}
78 	spin_unlock_bh(&nr_neigh_list_lock);
79 	return found;
80 }
81 
82 static void nr_remove_neigh(struct nr_neigh *);
83 
84 /*
85  *	Add a new route to a node, and in the process add the node and the
86  *	neighbour if it is new.
87  */
88 static int __must_check nr_add_node(ax25_address *nr, const char *mnemonic,
89 	ax25_address *ax25, ax25_digi *ax25_digi, struct net_device *dev,
90 	int quality, int obs_count)
91 {
92 	struct nr_node  *nr_node;
93 	struct nr_neigh *nr_neigh;
94 	struct nr_route nr_route;
95 	int i, found;
96 	struct net_device *odev;
97 
98 	if ((odev=nr_dev_get(nr)) != NULL) {	/* Can't add routes to ourself */
99 		dev_put(odev);
100 		return -EINVAL;
101 	}
102 
103 	nr_node = nr_node_get(nr);
104 
105 	nr_neigh = nr_neigh_get_dev(ax25, dev);
106 
107 	/*
108 	 * The L2 link to a neighbour has failed in the past
109 	 * and now a frame comes from this neighbour. We assume
110 	 * it was a temporary trouble with the link and reset the
111 	 * routes now (and not wait for a node broadcast).
112 	 */
113 	if (nr_neigh != NULL && nr_neigh->failed != 0 && quality == 0) {
114 		struct nr_node *nr_nodet;
115 
116 		spin_lock_bh(&nr_node_list_lock);
117 		nr_node_for_each(nr_nodet, &nr_node_list) {
118 			nr_node_lock(nr_nodet);
119 			for (i = 0; i < nr_nodet->count; i++)
120 				if (nr_nodet->routes[i].neighbour == nr_neigh)
121 					if (i < nr_nodet->which)
122 						nr_nodet->which = i;
123 			nr_node_unlock(nr_nodet);
124 		}
125 		spin_unlock_bh(&nr_node_list_lock);
126 	}
127 
128 	if (nr_neigh != NULL)
129 		nr_neigh->failed = 0;
130 
131 	if (quality == 0 && nr_neigh != NULL && nr_node != NULL) {
132 		nr_neigh_put(nr_neigh);
133 		nr_node_put(nr_node);
134 		return 0;
135 	}
136 
137 	if (nr_neigh == NULL) {
138 		if ((nr_neigh = kmalloc(sizeof(*nr_neigh), GFP_ATOMIC)) == NULL) {
139 			if (nr_node)
140 				nr_node_put(nr_node);
141 			return -ENOMEM;
142 		}
143 
144 		nr_neigh->callsign = *ax25;
145 		nr_neigh->digipeat = NULL;
146 		nr_neigh->ax25     = NULL;
147 		nr_neigh->dev      = dev;
148 		nr_neigh->quality  = sysctl_netrom_default_path_quality;
149 		nr_neigh->locked   = 0;
150 		nr_neigh->count    = 0;
151 		nr_neigh->number   = nr_neigh_no++;
152 		nr_neigh->failed   = 0;
153 		atomic_set(&nr_neigh->refcount, 1);
154 
155 		if (ax25_digi != NULL && ax25_digi->ndigi > 0) {
156 			nr_neigh->digipeat = kmemdup(ax25_digi,
157 						     sizeof(*ax25_digi),
158 						     GFP_KERNEL);
159 			if (nr_neigh->digipeat == NULL) {
160 				kfree(nr_neigh);
161 				if (nr_node)
162 					nr_node_put(nr_node);
163 				return -ENOMEM;
164 			}
165 		}
166 
167 		spin_lock_bh(&nr_neigh_list_lock);
168 		hlist_add_head(&nr_neigh->neigh_node, &nr_neigh_list);
169 		nr_neigh_hold(nr_neigh);
170 		spin_unlock_bh(&nr_neigh_list_lock);
171 	}
172 
173 	if (quality != 0 && ax25cmp(nr, ax25) == 0 && !nr_neigh->locked)
174 		nr_neigh->quality = quality;
175 
176 	if (nr_node == NULL) {
177 		if ((nr_node = kmalloc(sizeof(*nr_node), GFP_ATOMIC)) == NULL) {
178 			if (nr_neigh)
179 				nr_neigh_put(nr_neigh);
180 			return -ENOMEM;
181 		}
182 
183 		nr_node->callsign = *nr;
184 		strcpy(nr_node->mnemonic, mnemonic);
185 
186 		nr_node->which = 0;
187 		nr_node->count = 1;
188 		atomic_set(&nr_node->refcount, 1);
189 		spin_lock_init(&nr_node->node_lock);
190 
191 		nr_node->routes[0].quality   = quality;
192 		nr_node->routes[0].obs_count = obs_count;
193 		nr_node->routes[0].neighbour = nr_neigh;
194 
195 		nr_neigh_hold(nr_neigh);
196 		nr_neigh->count++;
197 
198 		spin_lock_bh(&nr_node_list_lock);
199 		hlist_add_head(&nr_node->node_node, &nr_node_list);
200 		/* refcount initialized at 1 */
201 		spin_unlock_bh(&nr_node_list_lock);
202 
203 		return 0;
204 	}
205 	nr_node_lock(nr_node);
206 
207 	if (quality != 0)
208 		strcpy(nr_node->mnemonic, mnemonic);
209 
210 	for (found = 0, i = 0; i < nr_node->count; i++) {
211 		if (nr_node->routes[i].neighbour == nr_neigh) {
212 			nr_node->routes[i].quality   = quality;
213 			nr_node->routes[i].obs_count = obs_count;
214 			found = 1;
215 			break;
216 		}
217 	}
218 
219 	if (!found) {
220 		/* We have space at the bottom, slot it in */
221 		if (nr_node->count < 3) {
222 			nr_node->routes[2] = nr_node->routes[1];
223 			nr_node->routes[1] = nr_node->routes[0];
224 
225 			nr_node->routes[0].quality   = quality;
226 			nr_node->routes[0].obs_count = obs_count;
227 			nr_node->routes[0].neighbour = nr_neigh;
228 
229 			nr_node->which++;
230 			nr_node->count++;
231 			nr_neigh_hold(nr_neigh);
232 			nr_neigh->count++;
233 		} else {
234 			/* It must be better than the worst */
235 			if (quality > nr_node->routes[2].quality) {
236 				nr_node->routes[2].neighbour->count--;
237 				nr_neigh_put(nr_node->routes[2].neighbour);
238 
239 				if (nr_node->routes[2].neighbour->count == 0 && !nr_node->routes[2].neighbour->locked)
240 					nr_remove_neigh(nr_node->routes[2].neighbour);
241 
242 				nr_node->routes[2].quality   = quality;
243 				nr_node->routes[2].obs_count = obs_count;
244 				nr_node->routes[2].neighbour = nr_neigh;
245 
246 				nr_neigh_hold(nr_neigh);
247 				nr_neigh->count++;
248 			}
249 		}
250 	}
251 
252 	/* Now re-sort the routes in quality order */
253 	switch (nr_node->count) {
254 	case 3:
255 		if (nr_node->routes[1].quality > nr_node->routes[0].quality) {
256 			switch (nr_node->which) {
257 			case 0:
258 				nr_node->which = 1;
259 				break;
260 			case 1:
261 				nr_node->which = 0;
262 				break;
263 			}
264 			nr_route           = nr_node->routes[0];
265 			nr_node->routes[0] = nr_node->routes[1];
266 			nr_node->routes[1] = nr_route;
267 		}
268 		if (nr_node->routes[2].quality > nr_node->routes[1].quality) {
269 			switch (nr_node->which) {
270 			case 1:  nr_node->which = 2;
271 				break;
272 
273 			case 2:  nr_node->which = 1;
274 				break;
275 
276 			default:
277 				break;
278 			}
279 			nr_route           = nr_node->routes[1];
280 			nr_node->routes[1] = nr_node->routes[2];
281 			nr_node->routes[2] = nr_route;
282 		}
283 	case 2:
284 		if (nr_node->routes[1].quality > nr_node->routes[0].quality) {
285 			switch (nr_node->which) {
286 			case 0:  nr_node->which = 1;
287 				break;
288 
289 			case 1:  nr_node->which = 0;
290 				break;
291 
292 			default: break;
293 			}
294 			nr_route           = nr_node->routes[0];
295 			nr_node->routes[0] = nr_node->routes[1];
296 			nr_node->routes[1] = nr_route;
297 			}
298 	case 1:
299 		break;
300 	}
301 
302 	for (i = 0; i < nr_node->count; i++) {
303 		if (nr_node->routes[i].neighbour == nr_neigh) {
304 			if (i < nr_node->which)
305 				nr_node->which = i;
306 			break;
307 		}
308 	}
309 
310 	nr_neigh_put(nr_neigh);
311 	nr_node_unlock(nr_node);
312 	nr_node_put(nr_node);
313 	return 0;
314 }
315 
316 static inline void __nr_remove_node(struct nr_node *nr_node)
317 {
318 	hlist_del_init(&nr_node->node_node);
319 	nr_node_put(nr_node);
320 }
321 
322 #define nr_remove_node_locked(__node) \
323 	__nr_remove_node(__node)
324 
325 static void nr_remove_node(struct nr_node *nr_node)
326 {
327 	spin_lock_bh(&nr_node_list_lock);
328 	__nr_remove_node(nr_node);
329 	spin_unlock_bh(&nr_node_list_lock);
330 }
331 
332 static inline void __nr_remove_neigh(struct nr_neigh *nr_neigh)
333 {
334 	hlist_del_init(&nr_neigh->neigh_node);
335 	nr_neigh_put(nr_neigh);
336 }
337 
338 #define nr_remove_neigh_locked(__neigh) \
339 	__nr_remove_neigh(__neigh)
340 
341 static void nr_remove_neigh(struct nr_neigh *nr_neigh)
342 {
343 	spin_lock_bh(&nr_neigh_list_lock);
344 	__nr_remove_neigh(nr_neigh);
345 	spin_unlock_bh(&nr_neigh_list_lock);
346 }
347 
348 /*
349  *	"Delete" a node. Strictly speaking remove a route to a node. The node
350  *	is only deleted if no routes are left to it.
351  */
352 static int nr_del_node(ax25_address *callsign, ax25_address *neighbour, struct net_device *dev)
353 {
354 	struct nr_node  *nr_node;
355 	struct nr_neigh *nr_neigh;
356 	int i;
357 
358 	nr_node = nr_node_get(callsign);
359 
360 	if (nr_node == NULL)
361 		return -EINVAL;
362 
363 	nr_neigh = nr_neigh_get_dev(neighbour, dev);
364 
365 	if (nr_neigh == NULL) {
366 		nr_node_put(nr_node);
367 		return -EINVAL;
368 	}
369 
370 	nr_node_lock(nr_node);
371 	for (i = 0; i < nr_node->count; i++) {
372 		if (nr_node->routes[i].neighbour == nr_neigh) {
373 			nr_neigh->count--;
374 			nr_neigh_put(nr_neigh);
375 
376 			if (nr_neigh->count == 0 && !nr_neigh->locked)
377 				nr_remove_neigh(nr_neigh);
378 			nr_neigh_put(nr_neigh);
379 
380 			nr_node->count--;
381 
382 			if (nr_node->count == 0) {
383 				nr_remove_node(nr_node);
384 			} else {
385 				switch (i) {
386 				case 0:
387 					nr_node->routes[0] = nr_node->routes[1];
388 				case 1:
389 					nr_node->routes[1] = nr_node->routes[2];
390 				case 2:
391 					break;
392 				}
393 				nr_node_put(nr_node);
394 			}
395 			nr_node_unlock(nr_node);
396 
397 			return 0;
398 		}
399 	}
400 	nr_neigh_put(nr_neigh);
401 	nr_node_unlock(nr_node);
402 	nr_node_put(nr_node);
403 
404 	return -EINVAL;
405 }
406 
407 /*
408  *	Lock a neighbour with a quality.
409  */
410 static int __must_check nr_add_neigh(ax25_address *callsign,
411 	ax25_digi *ax25_digi, struct net_device *dev, unsigned int quality)
412 {
413 	struct nr_neigh *nr_neigh;
414 
415 	nr_neigh = nr_neigh_get_dev(callsign, dev);
416 	if (nr_neigh) {
417 		nr_neigh->quality = quality;
418 		nr_neigh->locked  = 1;
419 		nr_neigh_put(nr_neigh);
420 		return 0;
421 	}
422 
423 	if ((nr_neigh = kmalloc(sizeof(*nr_neigh), GFP_ATOMIC)) == NULL)
424 		return -ENOMEM;
425 
426 	nr_neigh->callsign = *callsign;
427 	nr_neigh->digipeat = NULL;
428 	nr_neigh->ax25     = NULL;
429 	nr_neigh->dev      = dev;
430 	nr_neigh->quality  = quality;
431 	nr_neigh->locked   = 1;
432 	nr_neigh->count    = 0;
433 	nr_neigh->number   = nr_neigh_no++;
434 	nr_neigh->failed   = 0;
435 	atomic_set(&nr_neigh->refcount, 1);
436 
437 	if (ax25_digi != NULL && ax25_digi->ndigi > 0) {
438 		nr_neigh->digipeat = kmemdup(ax25_digi, sizeof(*ax25_digi),
439 					     GFP_KERNEL);
440 		if (nr_neigh->digipeat == NULL) {
441 			kfree(nr_neigh);
442 			return -ENOMEM;
443 		}
444 	}
445 
446 	spin_lock_bh(&nr_neigh_list_lock);
447 	hlist_add_head(&nr_neigh->neigh_node, &nr_neigh_list);
448 	/* refcount is initialized at 1 */
449 	spin_unlock_bh(&nr_neigh_list_lock);
450 
451 	return 0;
452 }
453 
454 /*
455  *	"Delete" a neighbour. The neighbour is only removed if the number
456  *	of nodes that may use it is zero.
457  */
458 static int nr_del_neigh(ax25_address *callsign, struct net_device *dev, unsigned int quality)
459 {
460 	struct nr_neigh *nr_neigh;
461 
462 	nr_neigh = nr_neigh_get_dev(callsign, dev);
463 
464 	if (nr_neigh == NULL) return -EINVAL;
465 
466 	nr_neigh->quality = quality;
467 	nr_neigh->locked  = 0;
468 
469 	if (nr_neigh->count == 0)
470 		nr_remove_neigh(nr_neigh);
471 	nr_neigh_put(nr_neigh);
472 
473 	return 0;
474 }
475 
476 /*
477  *	Decrement the obsolescence count by one. If a route is reduced to a
478  *	count of zero, remove it. Also remove any unlocked neighbours with
479  *	zero nodes routing via it.
480  */
481 static int nr_dec_obs(void)
482 {
483 	struct nr_neigh *nr_neigh;
484 	struct nr_node  *s;
485 	struct hlist_node *nodet;
486 	int i;
487 
488 	spin_lock_bh(&nr_node_list_lock);
489 	nr_node_for_each_safe(s, nodet, &nr_node_list) {
490 		nr_node_lock(s);
491 		for (i = 0; i < s->count; i++) {
492 			switch (s->routes[i].obs_count) {
493 			case 0:		/* A locked entry */
494 				break;
495 
496 			case 1:		/* From 1 -> 0 */
497 				nr_neigh = s->routes[i].neighbour;
498 
499 				nr_neigh->count--;
500 				nr_neigh_put(nr_neigh);
501 
502 				if (nr_neigh->count == 0 && !nr_neigh->locked)
503 					nr_remove_neigh(nr_neigh);
504 
505 				s->count--;
506 
507 				switch (i) {
508 				case 0:
509 					s->routes[0] = s->routes[1];
510 					/* Fallthrough */
511 				case 1:
512 					s->routes[1] = s->routes[2];
513 				case 2:
514 					break;
515 				}
516 				break;
517 
518 			default:
519 				s->routes[i].obs_count--;
520 				break;
521 
522 			}
523 		}
524 
525 		if (s->count <= 0)
526 			nr_remove_node_locked(s);
527 		nr_node_unlock(s);
528 	}
529 	spin_unlock_bh(&nr_node_list_lock);
530 
531 	return 0;
532 }
533 
534 /*
535  *	A device has been removed. Remove its routes and neighbours.
536  */
537 void nr_rt_device_down(struct net_device *dev)
538 {
539 	struct nr_neigh *s;
540 	struct hlist_node *nodet, *node2t;
541 	struct nr_node  *t;
542 	int i;
543 
544 	spin_lock_bh(&nr_neigh_list_lock);
545 	nr_neigh_for_each_safe(s, nodet, &nr_neigh_list) {
546 		if (s->dev == dev) {
547 			spin_lock_bh(&nr_node_list_lock);
548 			nr_node_for_each_safe(t, node2t, &nr_node_list) {
549 				nr_node_lock(t);
550 				for (i = 0; i < t->count; i++) {
551 					if (t->routes[i].neighbour == s) {
552 						t->count--;
553 
554 						switch (i) {
555 						case 0:
556 							t->routes[0] = t->routes[1];
557 						case 1:
558 							t->routes[1] = t->routes[2];
559 						case 2:
560 							break;
561 						}
562 					}
563 				}
564 
565 				if (t->count <= 0)
566 					nr_remove_node_locked(t);
567 				nr_node_unlock(t);
568 			}
569 			spin_unlock_bh(&nr_node_list_lock);
570 
571 			nr_remove_neigh_locked(s);
572 		}
573 	}
574 	spin_unlock_bh(&nr_neigh_list_lock);
575 }
576 
577 /*
578  *	Check that the device given is a valid AX.25 interface that is "up".
579  *	Or a valid ethernet interface with an AX.25 callsign binding.
580  */
581 static struct net_device *nr_ax25_dev_get(char *devname)
582 {
583 	struct net_device *dev;
584 
585 	if ((dev = dev_get_by_name(&init_net, devname)) == NULL)
586 		return NULL;
587 
588 	if ((dev->flags & IFF_UP) && dev->type == ARPHRD_AX25)
589 		return dev;
590 
591 	dev_put(dev);
592 	return NULL;
593 }
594 
595 /*
596  *	Find the first active NET/ROM device, usually "nr0".
597  */
598 struct net_device *nr_dev_first(void)
599 {
600 	struct net_device *dev, *first = NULL;
601 
602 	rcu_read_lock();
603 	for_each_netdev_rcu(&init_net, dev) {
604 		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM)
605 			if (first == NULL || strncmp(dev->name, first->name, 3) < 0)
606 				first = dev;
607 	}
608 	if (first)
609 		dev_hold(first);
610 	rcu_read_unlock();
611 
612 	return first;
613 }
614 
615 /*
616  *	Find the NET/ROM device for the given callsign.
617  */
618 struct net_device *nr_dev_get(ax25_address *addr)
619 {
620 	struct net_device *dev;
621 
622 	rcu_read_lock();
623 	for_each_netdev_rcu(&init_net, dev) {
624 		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM &&
625 		    ax25cmp(addr, (ax25_address *)dev->dev_addr) == 0) {
626 			dev_hold(dev);
627 			goto out;
628 		}
629 	}
630 	dev = NULL;
631 out:
632 	rcu_read_unlock();
633 	return dev;
634 }
635 
636 static ax25_digi *nr_call_to_digi(ax25_digi *digi, int ndigis,
637 	ax25_address *digipeaters)
638 {
639 	int i;
640 
641 	if (ndigis == 0)
642 		return NULL;
643 
644 	for (i = 0; i < ndigis; i++) {
645 		digi->calls[i]    = digipeaters[i];
646 		digi->repeated[i] = 0;
647 	}
648 
649 	digi->ndigi      = ndigis;
650 	digi->lastrepeat = -1;
651 
652 	return digi;
653 }
654 
655 /*
656  *	Handle the ioctls that control the routing functions.
657  */
658 int nr_rt_ioctl(unsigned int cmd, void __user *arg)
659 {
660 	struct nr_route_struct nr_route;
661 	struct net_device *dev;
662 	ax25_digi digi;
663 	int ret;
664 
665 	switch (cmd) {
666 	case SIOCADDRT:
667 		if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct)))
668 			return -EFAULT;
669 		if (nr_route.ndigis > AX25_MAX_DIGIS)
670 			return -EINVAL;
671 		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)
672 			return -EINVAL;
673 		switch (nr_route.type) {
674 		case NETROM_NODE:
675 			if (strnlen(nr_route.mnemonic, 7) == 7) {
676 				ret = -EINVAL;
677 				break;
678 			}
679 
680 			ret = nr_add_node(&nr_route.callsign,
681 				nr_route.mnemonic,
682 				&nr_route.neighbour,
683 				nr_call_to_digi(&digi, nr_route.ndigis,
684 						nr_route.digipeaters),
685 				dev, nr_route.quality,
686 				nr_route.obs_count);
687 			break;
688 		case NETROM_NEIGH:
689 			ret = nr_add_neigh(&nr_route.callsign,
690 				nr_call_to_digi(&digi, nr_route.ndigis,
691 						nr_route.digipeaters),
692 				dev, nr_route.quality);
693 			break;
694 		default:
695 			ret = -EINVAL;
696 		}
697 		dev_put(dev);
698 		return ret;
699 
700 	case SIOCDELRT:
701 		if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct)))
702 			return -EFAULT;
703 		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)
704 			return -EINVAL;
705 		switch (nr_route.type) {
706 		case NETROM_NODE:
707 			ret = nr_del_node(&nr_route.callsign,
708 				&nr_route.neighbour, dev);
709 			break;
710 		case NETROM_NEIGH:
711 			ret = nr_del_neigh(&nr_route.callsign,
712 				dev, nr_route.quality);
713 			break;
714 		default:
715 			ret = -EINVAL;
716 		}
717 		dev_put(dev);
718 		return ret;
719 
720 	case SIOCNRDECOBS:
721 		return nr_dec_obs();
722 
723 	default:
724 		return -EINVAL;
725 	}
726 
727 	return 0;
728 }
729 
730 /*
731  * 	A level 2 link has timed out, therefore it appears to be a poor link,
732  *	then don't use that neighbour until it is reset.
733  */
734 void nr_link_failed(ax25_cb *ax25, int reason)
735 {
736 	struct nr_neigh *s, *nr_neigh = NULL;
737 	struct nr_node  *nr_node = NULL;
738 
739 	spin_lock_bh(&nr_neigh_list_lock);
740 	nr_neigh_for_each(s, &nr_neigh_list) {
741 		if (s->ax25 == ax25) {
742 			nr_neigh_hold(s);
743 			nr_neigh = s;
744 			break;
745 		}
746 	}
747 	spin_unlock_bh(&nr_neigh_list_lock);
748 
749 	if (nr_neigh == NULL)
750 		return;
751 
752 	nr_neigh->ax25 = NULL;
753 	ax25_cb_put(ax25);
754 
755 	if (++nr_neigh->failed < sysctl_netrom_link_fails_count) {
756 		nr_neigh_put(nr_neigh);
757 		return;
758 	}
759 	spin_lock_bh(&nr_node_list_lock);
760 	nr_node_for_each(nr_node, &nr_node_list) {
761 		nr_node_lock(nr_node);
762 		if (nr_node->which < nr_node->count &&
763 		    nr_node->routes[nr_node->which].neighbour == nr_neigh)
764 			nr_node->which++;
765 		nr_node_unlock(nr_node);
766 	}
767 	spin_unlock_bh(&nr_node_list_lock);
768 	nr_neigh_put(nr_neigh);
769 }
770 
771 /*
772  *	Route a frame to an appropriate AX.25 connection. A NULL ax25_cb
773  *	indicates an internally generated frame.
774  */
775 int nr_route_frame(struct sk_buff *skb, ax25_cb *ax25)
776 {
777 	ax25_address *nr_src, *nr_dest;
778 	struct nr_neigh *nr_neigh;
779 	struct nr_node  *nr_node;
780 	struct net_device *dev;
781 	unsigned char *dptr;
782 	ax25_cb *ax25s;
783 	int ret;
784 	struct sk_buff *skbn;
785 
786 
787 	nr_src  = (ax25_address *)(skb->data + 0);
788 	nr_dest = (ax25_address *)(skb->data + 7);
789 
790 	if (ax25 != NULL) {
791 		ret = nr_add_node(nr_src, "", &ax25->dest_addr, ax25->digipeat,
792 				  ax25->ax25_dev->dev, 0,
793 				  sysctl_netrom_obsolescence_count_initialiser);
794 		if (ret)
795 			return ret;
796 	}
797 
798 	if ((dev = nr_dev_get(nr_dest)) != NULL) {	/* Its for me */
799 		if (ax25 == NULL)			/* Its from me */
800 			ret = nr_loopback_queue(skb);
801 		else
802 			ret = nr_rx_frame(skb, dev);
803 		dev_put(dev);
804 		return ret;
805 	}
806 
807 	if (!sysctl_netrom_routing_control && ax25 != NULL)
808 		return 0;
809 
810 	/* Its Time-To-Live has expired */
811 	if (skb->data[14] == 1) {
812 		return 0;
813 	}
814 
815 	nr_node = nr_node_get(nr_dest);
816 	if (nr_node == NULL)
817 		return 0;
818 	nr_node_lock(nr_node);
819 
820 	if (nr_node->which >= nr_node->count) {
821 		nr_node_unlock(nr_node);
822 		nr_node_put(nr_node);
823 		return 0;
824 	}
825 
826 	nr_neigh = nr_node->routes[nr_node->which].neighbour;
827 
828 	if ((dev = nr_dev_first()) == NULL) {
829 		nr_node_unlock(nr_node);
830 		nr_node_put(nr_node);
831 		return 0;
832 	}
833 
834 	/* We are going to change the netrom headers so we should get our
835 	   own skb, we also did not know until now how much header space
836 	   we had to reserve... - RXQ */
837 	if ((skbn=skb_copy_expand(skb, dev->hard_header_len, 0, GFP_ATOMIC)) == NULL) {
838 		nr_node_unlock(nr_node);
839 		nr_node_put(nr_node);
840 		dev_put(dev);
841 		return 0;
842 	}
843 	kfree_skb(skb);
844 	skb=skbn;
845 	skb->data[14]--;
846 
847 	dptr  = skb_push(skb, 1);
848 	*dptr = AX25_P_NETROM;
849 
850 	ax25s = nr_neigh->ax25;
851 	nr_neigh->ax25 = ax25_send_frame(skb, 256,
852 					 (ax25_address *)dev->dev_addr,
853 					 &nr_neigh->callsign,
854 					 nr_neigh->digipeat, nr_neigh->dev);
855 	if (ax25s)
856 		ax25_cb_put(ax25s);
857 
858 	dev_put(dev);
859 	ret = (nr_neigh->ax25 != NULL);
860 	nr_node_unlock(nr_node);
861 	nr_node_put(nr_node);
862 
863 	return ret;
864 }
865 
866 #ifdef CONFIG_PROC_FS
867 
868 static void *nr_node_start(struct seq_file *seq, loff_t *pos)
869 {
870 	spin_lock_bh(&nr_node_list_lock);
871 	return seq_hlist_start_head(&nr_node_list, *pos);
872 }
873 
874 static void *nr_node_next(struct seq_file *seq, void *v, loff_t *pos)
875 {
876 	return seq_hlist_next(v, &nr_node_list, pos);
877 }
878 
879 static void nr_node_stop(struct seq_file *seq, void *v)
880 {
881 	spin_unlock_bh(&nr_node_list_lock);
882 }
883 
884 static int nr_node_show(struct seq_file *seq, void *v)
885 {
886 	char buf[11];
887 	int i;
888 
889 	if (v == SEQ_START_TOKEN)
890 		seq_puts(seq,
891 			 "callsign  mnemonic w n qual obs neigh qual obs neigh qual obs neigh\n");
892 	else {
893 		struct nr_node *nr_node = hlist_entry(v, struct nr_node,
894 						      node_node);
895 
896 		nr_node_lock(nr_node);
897 		seq_printf(seq, "%-9s %-7s  %d %d",
898 			ax2asc(buf, &nr_node->callsign),
899 			(nr_node->mnemonic[0] == '\0') ? "*" : nr_node->mnemonic,
900 			nr_node->which + 1,
901 			nr_node->count);
902 
903 		for (i = 0; i < nr_node->count; i++) {
904 			seq_printf(seq, "  %3d   %d %05d",
905 				nr_node->routes[i].quality,
906 				nr_node->routes[i].obs_count,
907 				nr_node->routes[i].neighbour->number);
908 		}
909 		nr_node_unlock(nr_node);
910 
911 		seq_puts(seq, "\n");
912 	}
913 	return 0;
914 }
915 
916 static const struct seq_operations nr_node_seqops = {
917 	.start = nr_node_start,
918 	.next = nr_node_next,
919 	.stop = nr_node_stop,
920 	.show = nr_node_show,
921 };
922 
923 static int nr_node_info_open(struct inode *inode, struct file *file)
924 {
925 	return seq_open(file, &nr_node_seqops);
926 }
927 
928 const struct file_operations nr_nodes_fops = {
929 	.owner = THIS_MODULE,
930 	.open = nr_node_info_open,
931 	.read = seq_read,
932 	.llseek = seq_lseek,
933 	.release = seq_release,
934 };
935 
936 static void *nr_neigh_start(struct seq_file *seq, loff_t *pos)
937 {
938 	spin_lock_bh(&nr_neigh_list_lock);
939 	return seq_hlist_start_head(&nr_neigh_list, *pos);
940 }
941 
942 static void *nr_neigh_next(struct seq_file *seq, void *v, loff_t *pos)
943 {
944 	return seq_hlist_next(v, &nr_neigh_list, pos);
945 }
946 
947 static void nr_neigh_stop(struct seq_file *seq, void *v)
948 {
949 	spin_unlock_bh(&nr_neigh_list_lock);
950 }
951 
952 static int nr_neigh_show(struct seq_file *seq, void *v)
953 {
954 	char buf[11];
955 	int i;
956 
957 	if (v == SEQ_START_TOKEN)
958 		seq_puts(seq, "addr  callsign  dev  qual lock count failed digipeaters\n");
959 	else {
960 		struct nr_neigh *nr_neigh;
961 
962 		nr_neigh = hlist_entry(v, struct nr_neigh, neigh_node);
963 		seq_printf(seq, "%05d %-9s %-4s  %3d    %d   %3d    %3d",
964 			nr_neigh->number,
965 			ax2asc(buf, &nr_neigh->callsign),
966 			nr_neigh->dev ? nr_neigh->dev->name : "???",
967 			nr_neigh->quality,
968 			nr_neigh->locked,
969 			nr_neigh->count,
970 			nr_neigh->failed);
971 
972 		if (nr_neigh->digipeat != NULL) {
973 			for (i = 0; i < nr_neigh->digipeat->ndigi; i++)
974 				seq_printf(seq, " %s",
975 					   ax2asc(buf, &nr_neigh->digipeat->calls[i]));
976 		}
977 
978 		seq_puts(seq, "\n");
979 	}
980 	return 0;
981 }
982 
983 static const struct seq_operations nr_neigh_seqops = {
984 	.start = nr_neigh_start,
985 	.next = nr_neigh_next,
986 	.stop = nr_neigh_stop,
987 	.show = nr_neigh_show,
988 };
989 
990 static int nr_neigh_info_open(struct inode *inode, struct file *file)
991 {
992 	return seq_open(file, &nr_neigh_seqops);
993 }
994 
995 const struct file_operations nr_neigh_fops = {
996 	.owner = THIS_MODULE,
997 	.open = nr_neigh_info_open,
998 	.read = seq_read,
999 	.llseek = seq_lseek,
1000 	.release = seq_release,
1001 };
1002 
1003 #endif
1004 
1005 /*
1006  *	Free all memory associated with the nodes and routes lists.
1007  */
1008 void __exit nr_rt_free(void)
1009 {
1010 	struct nr_neigh *s = NULL;
1011 	struct nr_node  *t = NULL;
1012 	struct hlist_node *nodet;
1013 
1014 	spin_lock_bh(&nr_neigh_list_lock);
1015 	spin_lock_bh(&nr_node_list_lock);
1016 	nr_node_for_each_safe(t, nodet, &nr_node_list) {
1017 		nr_node_lock(t);
1018 		nr_remove_node_locked(t);
1019 		nr_node_unlock(t);
1020 	}
1021 	nr_neigh_for_each_safe(s, nodet, &nr_neigh_list) {
1022 		while(s->count) {
1023 			s->count--;
1024 			nr_neigh_put(s);
1025 		}
1026 		nr_remove_neigh_locked(s);
1027 	}
1028 	spin_unlock_bh(&nr_node_list_lock);
1029 	spin_unlock_bh(&nr_neigh_list_lock);
1030 }
1031