xref: /openbmc/linux/net/netrom/nr_route.c (revision 64c70b1c)
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 <net/ax25.h>
21 #include <linux/inet.h>
22 #include <linux/netdevice.h>
23 #include <net/arp.h>
24 #include <linux/if_arp.h>
25 #include <linux/skbuff.h>
26 #include <net/sock.h>
27 #include <asm/uaccess.h>
28 #include <asm/system.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 
40 static unsigned int nr_neigh_no = 1;
41 
42 static HLIST_HEAD(nr_node_list);
43 static DEFINE_SPINLOCK(nr_node_list_lock);
44 static HLIST_HEAD(nr_neigh_list);
45 static DEFINE_SPINLOCK(nr_neigh_list_lock);
46 
47 static struct nr_node *nr_node_get(ax25_address *callsign)
48 {
49 	struct nr_node *found = NULL;
50 	struct nr_node *nr_node;
51 	struct hlist_node *node;
52 
53 	spin_lock_bh(&nr_node_list_lock);
54 	nr_node_for_each(nr_node, 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 	struct hlist_node *node;
70 
71 	spin_lock_bh(&nr_neigh_list_lock);
72 	nr_neigh_for_each(nr_neigh, node, &nr_neigh_list)
73 		if (ax25cmp(callsign, &nr_neigh->callsign) == 0 &&
74 		    nr_neigh->dev == dev) {
75 			nr_neigh_hold(nr_neigh);
76 			found = nr_neigh;
77 			break;
78 		}
79 	spin_unlock_bh(&nr_neigh_list_lock);
80 	return found;
81 }
82 
83 static void nr_remove_neigh(struct nr_neigh *);
84 
85 /*
86  *	Add a new route to a node, and in the process add the node and the
87  *	neighbour if it is new.
88  */
89 static int __must_check nr_add_node(ax25_address *nr, const char *mnemonic,
90 	ax25_address *ax25, ax25_digi *ax25_digi, struct net_device *dev,
91 	int quality, int obs_count)
92 {
93 	struct nr_node  *nr_node;
94 	struct nr_neigh *nr_neigh;
95 	struct nr_route nr_route;
96 	int i, found;
97 	struct net_device *odev;
98 
99 	if ((odev=nr_dev_get(nr)) != NULL) {	/* Can't add routes to ourself */
100 		dev_put(odev);
101 		return -EINVAL;
102 	}
103 
104 	nr_node = nr_node_get(nr);
105 
106 	nr_neigh = nr_neigh_get_dev(ax25, dev);
107 
108 	/*
109 	 * The L2 link to a neighbour has failed in the past
110 	 * and now a frame comes from this neighbour. We assume
111 	 * it was a temporary trouble with the link and reset the
112 	 * routes now (and not wait for a node broadcast).
113 	 */
114 	if (nr_neigh != NULL && nr_neigh->failed != 0 && quality == 0) {
115 		struct nr_node *nr_nodet;
116 		struct hlist_node *node;
117 
118 		spin_lock_bh(&nr_node_list_lock);
119 		nr_node_for_each(nr_nodet, node, &nr_node_list) {
120 			nr_node_lock(nr_nodet);
121 			for (i = 0; i < nr_nodet->count; i++)
122 				if (nr_nodet->routes[i].neighbour == nr_neigh)
123 					if (i < nr_nodet->which)
124 						nr_nodet->which = i;
125 			nr_node_unlock(nr_nodet);
126 		}
127 		spin_unlock_bh(&nr_node_list_lock);
128 	}
129 
130 	if (nr_neigh != NULL)
131 		nr_neigh->failed = 0;
132 
133 	if (quality == 0 && nr_neigh != NULL && nr_node != NULL) {
134 		nr_neigh_put(nr_neigh);
135 		nr_node_put(nr_node);
136 		return 0;
137 	}
138 
139 	if (nr_neigh == NULL) {
140 		if ((nr_neigh = kmalloc(sizeof(*nr_neigh), GFP_ATOMIC)) == NULL) {
141 			if (nr_node)
142 				nr_node_put(nr_node);
143 			return -ENOMEM;
144 		}
145 
146 		nr_neigh->callsign = *ax25;
147 		nr_neigh->digipeat = NULL;
148 		nr_neigh->ax25     = NULL;
149 		nr_neigh->dev      = dev;
150 		nr_neigh->quality  = sysctl_netrom_default_path_quality;
151 		nr_neigh->locked   = 0;
152 		nr_neigh->count    = 0;
153 		nr_neigh->number   = nr_neigh_no++;
154 		nr_neigh->failed   = 0;
155 		atomic_set(&nr_neigh->refcount, 1);
156 
157 		if (ax25_digi != NULL && ax25_digi->ndigi > 0) {
158 			nr_neigh->digipeat = kmemdup(ax25_digi,
159 						     sizeof(*ax25_digi),
160 						     GFP_KERNEL);
161 			if (nr_neigh->digipeat == NULL) {
162 				kfree(nr_neigh);
163 				if (nr_node)
164 					nr_node_put(nr_node);
165 				return -ENOMEM;
166 			}
167 		}
168 
169 		spin_lock_bh(&nr_neigh_list_lock);
170 		hlist_add_head(&nr_neigh->neigh_node, &nr_neigh_list);
171 		nr_neigh_hold(nr_neigh);
172 		spin_unlock_bh(&nr_neigh_list_lock);
173 	}
174 
175 	if (quality != 0 && ax25cmp(nr, ax25) == 0 && !nr_neigh->locked)
176 		nr_neigh->quality = quality;
177 
178 	if (nr_node == NULL) {
179 		if ((nr_node = kmalloc(sizeof(*nr_node), GFP_ATOMIC)) == NULL) {
180 			if (nr_neigh)
181 				nr_neigh_put(nr_neigh);
182 			return -ENOMEM;
183 		}
184 
185 		nr_node->callsign = *nr;
186 		strcpy(nr_node->mnemonic, mnemonic);
187 
188 		nr_node->which = 0;
189 		nr_node->count = 1;
190 		atomic_set(&nr_node->refcount, 1);
191 		spin_lock_init(&nr_node->node_lock);
192 
193 		nr_node->routes[0].quality   = quality;
194 		nr_node->routes[0].obs_count = obs_count;
195 		nr_node->routes[0].neighbour = nr_neigh;
196 
197 		nr_neigh_hold(nr_neigh);
198 		nr_neigh->count++;
199 
200 		spin_lock_bh(&nr_node_list_lock);
201 		hlist_add_head(&nr_node->node_node, &nr_node_list);
202 		/* refcount initialized at 1 */
203 		spin_unlock_bh(&nr_node_list_lock);
204 
205 		return 0;
206 	}
207 	nr_node_lock(nr_node);
208 
209 	if (quality != 0)
210 		strcpy(nr_node->mnemonic, mnemonic);
211 
212 	for (found = 0, i = 0; i < nr_node->count; i++) {
213 		if (nr_node->routes[i].neighbour == nr_neigh) {
214 			nr_node->routes[i].quality   = quality;
215 			nr_node->routes[i].obs_count = obs_count;
216 			found = 1;
217 			break;
218 		}
219 	}
220 
221 	if (!found) {
222 		/* We have space at the bottom, slot it in */
223 		if (nr_node->count < 3) {
224 			nr_node->routes[2] = nr_node->routes[1];
225 			nr_node->routes[1] = nr_node->routes[0];
226 
227 			nr_node->routes[0].quality   = quality;
228 			nr_node->routes[0].obs_count = obs_count;
229 			nr_node->routes[0].neighbour = nr_neigh;
230 
231 			nr_node->which++;
232 			nr_node->count++;
233 			nr_neigh_hold(nr_neigh);
234 			nr_neigh->count++;
235 		} else {
236 			/* It must be better than the worst */
237 			if (quality > nr_node->routes[2].quality) {
238 				nr_node->routes[2].neighbour->count--;
239 				nr_neigh_put(nr_node->routes[2].neighbour);
240 
241 				if (nr_node->routes[2].neighbour->count == 0 && !nr_node->routes[2].neighbour->locked)
242 					nr_remove_neigh(nr_node->routes[2].neighbour);
243 
244 				nr_node->routes[2].quality   = quality;
245 				nr_node->routes[2].obs_count = obs_count;
246 				nr_node->routes[2].neighbour = nr_neigh;
247 
248 				nr_neigh_hold(nr_neigh);
249 				nr_neigh->count++;
250 			}
251 		}
252 	}
253 
254 	/* Now re-sort the routes in quality order */
255 	switch (nr_node->count) {
256 	case 3:
257 		if (nr_node->routes[1].quality > nr_node->routes[0].quality) {
258 			switch (nr_node->which) {
259 				case 0:  nr_node->which = 1; break;
260 				case 1:  nr_node->which = 0; break;
261 				default: break;
262 			}
263 			nr_route           = nr_node->routes[0];
264 			nr_node->routes[0] = nr_node->routes[1];
265 			nr_node->routes[1] = nr_route;
266 		}
267 		if (nr_node->routes[2].quality > nr_node->routes[1].quality) {
268 			switch (nr_node->which) {
269 			case 1:  nr_node->which = 2;
270 				break;
271 
272 			case 2:  nr_node->which = 1;
273 				break;
274 
275 			default:
276 				break;
277 			}
278 			nr_route           = nr_node->routes[1];
279 			nr_node->routes[1] = nr_node->routes[2];
280 			nr_node->routes[2] = nr_route;
281 		}
282 	case 2:
283 		if (nr_node->routes[1].quality > nr_node->routes[0].quality) {
284 			switch (nr_node->which) {
285 			case 0:  nr_node->which = 1;
286 				break;
287 
288 			case 1:  nr_node->which = 0;
289 				break;
290 
291 			default: break;
292 			}
293 			nr_route           = nr_node->routes[0];
294 			nr_node->routes[0] = nr_node->routes[1];
295 			nr_node->routes[1] = nr_route;
296 			}
297 	case 1:
298 		break;
299 	}
300 
301 	for (i = 0; i < nr_node->count; i++) {
302 		if (nr_node->routes[i].neighbour == nr_neigh) {
303 			if (i < nr_node->which)
304 				nr_node->which = i;
305 			break;
306 		}
307 	}
308 
309 	nr_neigh_put(nr_neigh);
310 	nr_node_unlock(nr_node);
311 	nr_node_put(nr_node);
312 	return 0;
313 }
314 
315 static inline void __nr_remove_node(struct nr_node *nr_node)
316 {
317 	hlist_del_init(&nr_node->node_node);
318 	nr_node_put(nr_node);
319 }
320 
321 #define nr_remove_node_locked(__node) \
322 	__nr_remove_node(__node)
323 
324 static void nr_remove_node(struct nr_node *nr_node)
325 {
326 	spin_lock_bh(&nr_node_list_lock);
327 	__nr_remove_node(nr_node);
328 	spin_unlock_bh(&nr_node_list_lock);
329 }
330 
331 static inline void __nr_remove_neigh(struct nr_neigh *nr_neigh)
332 {
333 	hlist_del_init(&nr_neigh->neigh_node);
334 	nr_neigh_put(nr_neigh);
335 }
336 
337 #define nr_remove_neigh_locked(__neigh) \
338 	__nr_remove_neigh(__neigh)
339 
340 static void nr_remove_neigh(struct nr_neigh *nr_neigh)
341 {
342 	spin_lock_bh(&nr_neigh_list_lock);
343 	__nr_remove_neigh(nr_neigh);
344 	spin_unlock_bh(&nr_neigh_list_lock);
345 }
346 
347 /*
348  *	"Delete" a node. Strictly speaking remove a route to a node. The node
349  *	is only deleted if no routes are left to it.
350  */
351 static int nr_del_node(ax25_address *callsign, ax25_address *neighbour, struct net_device *dev)
352 {
353 	struct nr_node  *nr_node;
354 	struct nr_neigh *nr_neigh;
355 	int i;
356 
357 	nr_node = nr_node_get(callsign);
358 
359 	if (nr_node == NULL)
360 		return -EINVAL;
361 
362 	nr_neigh = nr_neigh_get_dev(neighbour, dev);
363 
364 	if (nr_neigh == NULL) {
365 		nr_node_put(nr_node);
366 		return -EINVAL;
367 	}
368 
369 	nr_node_lock(nr_node);
370 	for (i = 0; i < nr_node->count; i++) {
371 		if (nr_node->routes[i].neighbour == nr_neigh) {
372 			nr_neigh->count--;
373 			nr_neigh_put(nr_neigh);
374 
375 			if (nr_neigh->count == 0 && !nr_neigh->locked)
376 				nr_remove_neigh(nr_neigh);
377 			nr_neigh_put(nr_neigh);
378 
379 			nr_node->count--;
380 
381 			if (nr_node->count == 0) {
382 				nr_remove_node(nr_node);
383 			} else {
384 				switch (i) {
385 				case 0:
386 					nr_node->routes[0] = nr_node->routes[1];
387 				case 1:
388 					nr_node->routes[1] = nr_node->routes[2];
389 				case 2:
390 					break;
391 				}
392 				nr_node_put(nr_node);
393 			}
394 			nr_node_unlock(nr_node);
395 
396 			return 0;
397 		}
398 	}
399 	nr_neigh_put(nr_neigh);
400 	nr_node_unlock(nr_node);
401 	nr_node_put(nr_node);
402 
403 	return -EINVAL;
404 }
405 
406 /*
407  *	Lock a neighbour with a quality.
408  */
409 static int __must_check nr_add_neigh(ax25_address *callsign,
410 	ax25_digi *ax25_digi, struct net_device *dev, unsigned int quality)
411 {
412 	struct nr_neigh *nr_neigh;
413 
414 	nr_neigh = nr_neigh_get_dev(callsign, dev);
415 	if (nr_neigh) {
416 		nr_neigh->quality = quality;
417 		nr_neigh->locked  = 1;
418 		nr_neigh_put(nr_neigh);
419 		return 0;
420 	}
421 
422 	if ((nr_neigh = kmalloc(sizeof(*nr_neigh), GFP_ATOMIC)) == NULL)
423 		return -ENOMEM;
424 
425 	nr_neigh->callsign = *callsign;
426 	nr_neigh->digipeat = NULL;
427 	nr_neigh->ax25     = NULL;
428 	nr_neigh->dev      = dev;
429 	nr_neigh->quality  = quality;
430 	nr_neigh->locked   = 1;
431 	nr_neigh->count    = 0;
432 	nr_neigh->number   = nr_neigh_no++;
433 	nr_neigh->failed   = 0;
434 	atomic_set(&nr_neigh->refcount, 1);
435 
436 	if (ax25_digi != NULL && ax25_digi->ndigi > 0) {
437 		nr_neigh->digipeat = kmemdup(ax25_digi, sizeof(*ax25_digi),
438 					     GFP_KERNEL);
439 		if (nr_neigh->digipeat == NULL) {
440 			kfree(nr_neigh);
441 			return -ENOMEM;
442 		}
443 	}
444 
445 	spin_lock_bh(&nr_neigh_list_lock);
446 	hlist_add_head(&nr_neigh->neigh_node, &nr_neigh_list);
447 	/* refcount is initialized at 1 */
448 	spin_unlock_bh(&nr_neigh_list_lock);
449 
450 	return 0;
451 }
452 
453 /*
454  *	"Delete" a neighbour. The neighbour is only removed if the number
455  *	of nodes that may use it is zero.
456  */
457 static int nr_del_neigh(ax25_address *callsign, struct net_device *dev, unsigned int quality)
458 {
459 	struct nr_neigh *nr_neigh;
460 
461 	nr_neigh = nr_neigh_get_dev(callsign, dev);
462 
463 	if (nr_neigh == NULL) return -EINVAL;
464 
465 	nr_neigh->quality = quality;
466 	nr_neigh->locked  = 0;
467 
468 	if (nr_neigh->count == 0)
469 		nr_remove_neigh(nr_neigh);
470 	nr_neigh_put(nr_neigh);
471 
472 	return 0;
473 }
474 
475 /*
476  *	Decrement the obsolescence count by one. If a route is reduced to a
477  *	count of zero, remove it. Also remove any unlocked neighbours with
478  *	zero nodes routing via it.
479  */
480 static int nr_dec_obs(void)
481 {
482 	struct nr_neigh *nr_neigh;
483 	struct nr_node  *s;
484 	struct hlist_node *node, *nodet;
485 	int i;
486 
487 	spin_lock_bh(&nr_node_list_lock);
488 	nr_node_for_each_safe(s, node, nodet, &nr_node_list) {
489 		nr_node_lock(s);
490 		for (i = 0; i < s->count; i++) {
491 			switch (s->routes[i].obs_count) {
492 			case 0:		/* A locked entry */
493 				break;
494 
495 			case 1:		/* From 1 -> 0 */
496 				nr_neigh = s->routes[i].neighbour;
497 
498 				nr_neigh->count--;
499 				nr_neigh_put(nr_neigh);
500 
501 				if (nr_neigh->count == 0 && !nr_neigh->locked)
502 					nr_remove_neigh(nr_neigh);
503 
504 				s->count--;
505 
506 				switch (i) {
507 					case 0:
508 						s->routes[0] = s->routes[1];
509 					case 1:
510 						s->routes[1] = s->routes[2];
511 					case 2:
512 						break;
513 				}
514 				break;
515 
516 			default:
517 				s->routes[i].obs_count--;
518 				break;
519 
520 			}
521 		}
522 
523 		if (s->count <= 0)
524 			nr_remove_node_locked(s);
525 		nr_node_unlock(s);
526 	}
527 	spin_unlock_bh(&nr_node_list_lock);
528 
529 	return 0;
530 }
531 
532 /*
533  *	A device has been removed. Remove its routes and neighbours.
534  */
535 void nr_rt_device_down(struct net_device *dev)
536 {
537 	struct nr_neigh *s;
538 	struct hlist_node *node, *nodet, *node2, *node2t;
539 	struct nr_node  *t;
540 	int i;
541 
542 	spin_lock_bh(&nr_neigh_list_lock);
543 	nr_neigh_for_each_safe(s, node, nodet, &nr_neigh_list) {
544 		if (s->dev == dev) {
545 			spin_lock_bh(&nr_node_list_lock);
546 			nr_node_for_each_safe(t, node2, node2t, &nr_node_list) {
547 				nr_node_lock(t);
548 				for (i = 0; i < t->count; i++) {
549 					if (t->routes[i].neighbour == s) {
550 						t->count--;
551 
552 						switch (i) {
553 						case 0:
554 							t->routes[0] = t->routes[1];
555 						case 1:
556 							t->routes[1] = t->routes[2];
557 						case 2:
558 							break;
559 						}
560 					}
561 				}
562 
563 				if (t->count <= 0)
564 					nr_remove_node_locked(t);
565 				nr_node_unlock(t);
566 			}
567 			spin_unlock_bh(&nr_node_list_lock);
568 
569 			nr_remove_neigh_locked(s);
570 		}
571 	}
572 	spin_unlock_bh(&nr_neigh_list_lock);
573 }
574 
575 /*
576  *	Check that the device given is a valid AX.25 interface that is "up".
577  *	Or a valid ethernet interface with an AX.25 callsign binding.
578  */
579 static struct net_device *nr_ax25_dev_get(char *devname)
580 {
581 	struct net_device *dev;
582 
583 	if ((dev = dev_get_by_name(devname)) == NULL)
584 		return NULL;
585 
586 	if ((dev->flags & IFF_UP) && dev->type == ARPHRD_AX25)
587 		return dev;
588 
589 	dev_put(dev);
590 	return NULL;
591 }
592 
593 /*
594  *	Find the first active NET/ROM device, usually "nr0".
595  */
596 struct net_device *nr_dev_first(void)
597 {
598 	struct net_device *dev, *first = NULL;
599 
600 	read_lock(&dev_base_lock);
601 	for_each_netdev(dev) {
602 		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM)
603 			if (first == NULL || strncmp(dev->name, first->name, 3) < 0)
604 				first = dev;
605 	}
606 	if (first)
607 		dev_hold(first);
608 	read_unlock(&dev_base_lock);
609 
610 	return first;
611 }
612 
613 /*
614  *	Find the NET/ROM device for the given callsign.
615  */
616 struct net_device *nr_dev_get(ax25_address *addr)
617 {
618 	struct net_device *dev;
619 
620 	read_lock(&dev_base_lock);
621 	for_each_netdev(dev) {
622 		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM && ax25cmp(addr, (ax25_address *)dev->dev_addr) == 0) {
623 			dev_hold(dev);
624 			goto out;
625 		}
626 	}
627 	dev = NULL;
628 out:
629 	read_unlock(&dev_base_lock);
630 	return dev;
631 }
632 
633 static ax25_digi *nr_call_to_digi(int ndigis, ax25_address *digipeaters)
634 {
635 	static ax25_digi ax25_digi;
636 	int i;
637 
638 	if (ndigis == 0)
639 		return NULL;
640 
641 	for (i = 0; i < ndigis; i++) {
642 		ax25_digi.calls[i]    = digipeaters[i];
643 		ax25_digi.repeated[i] = 0;
644 	}
645 
646 	ax25_digi.ndigi      = ndigis;
647 	ax25_digi.lastrepeat = -1;
648 
649 	return &ax25_digi;
650 }
651 
652 /*
653  *	Handle the ioctls that control the routing functions.
654  */
655 int nr_rt_ioctl(unsigned int cmd, void __user *arg)
656 {
657 	struct nr_route_struct nr_route;
658 	struct net_device *dev;
659 	int ret;
660 
661 	switch (cmd) {
662 	case SIOCADDRT:
663 		if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct)))
664 			return -EFAULT;
665 		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)
666 			return -EINVAL;
667 		if (nr_route.ndigis < 0 || nr_route.ndigis > AX25_MAX_DIGIS) {
668 			dev_put(dev);
669 			return -EINVAL;
670 		}
671 		switch (nr_route.type) {
672 		case NETROM_NODE:
673 			ret = nr_add_node(&nr_route.callsign,
674 				nr_route.mnemonic,
675 				&nr_route.neighbour,
676 				nr_call_to_digi(nr_route.ndigis, nr_route.digipeaters),
677 				dev, nr_route.quality,
678 				nr_route.obs_count);
679 			break;
680 		case NETROM_NEIGH:
681 			ret = nr_add_neigh(&nr_route.callsign,
682 				nr_call_to_digi(nr_route.ndigis, nr_route.digipeaters),
683 				dev, nr_route.quality);
684 			break;
685 		default:
686 			ret = -EINVAL;
687 		}
688 		dev_put(dev);
689 		return ret;
690 
691 	case SIOCDELRT:
692 		if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct)))
693 			return -EFAULT;
694 		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)
695 			return -EINVAL;
696 		switch (nr_route.type) {
697 		case NETROM_NODE:
698 			ret = nr_del_node(&nr_route.callsign,
699 				&nr_route.neighbour, dev);
700 			break;
701 		case NETROM_NEIGH:
702 			ret = nr_del_neigh(&nr_route.callsign,
703 				dev, nr_route.quality);
704 			break;
705 		default:
706 			ret = -EINVAL;
707 		}
708 		dev_put(dev);
709 		return ret;
710 
711 	case SIOCNRDECOBS:
712 		return nr_dec_obs();
713 
714 	default:
715 		return -EINVAL;
716 	}
717 
718 	return 0;
719 }
720 
721 /*
722  * 	A level 2 link has timed out, therefore it appears to be a poor link,
723  *	then don't use that neighbour until it is reset.
724  */
725 void nr_link_failed(ax25_cb *ax25, int reason)
726 {
727 	struct nr_neigh *s, *nr_neigh = NULL;
728 	struct hlist_node *node;
729 	struct nr_node  *nr_node = NULL;
730 
731 	spin_lock_bh(&nr_neigh_list_lock);
732 	nr_neigh_for_each(s, node, &nr_neigh_list) {
733 		if (s->ax25 == ax25) {
734 			nr_neigh_hold(s);
735 			nr_neigh = s;
736 			break;
737 		}
738 	}
739 	spin_unlock_bh(&nr_neigh_list_lock);
740 
741 	if (nr_neigh == NULL)
742 		return;
743 
744 	nr_neigh->ax25 = NULL;
745 	ax25_cb_put(ax25);
746 
747 	if (++nr_neigh->failed < sysctl_netrom_link_fails_count) {
748 		nr_neigh_put(nr_neigh);
749 		return;
750 	}
751 	spin_lock_bh(&nr_node_list_lock);
752 	nr_node_for_each(nr_node, node, &nr_node_list) {
753 		nr_node_lock(nr_node);
754 		if (nr_node->which < nr_node->count &&
755 		    nr_node->routes[nr_node->which].neighbour == nr_neigh)
756 			nr_node->which++;
757 		nr_node_unlock(nr_node);
758 	}
759 	spin_unlock_bh(&nr_node_list_lock);
760 	nr_neigh_put(nr_neigh);
761 }
762 
763 /*
764  *	Route a frame to an appropriate AX.25 connection. A NULL ax25_cb
765  *	indicates an internally generated frame.
766  */
767 int nr_route_frame(struct sk_buff *skb, ax25_cb *ax25)
768 {
769 	ax25_address *nr_src, *nr_dest;
770 	struct nr_neigh *nr_neigh;
771 	struct nr_node  *nr_node;
772 	struct net_device *dev;
773 	unsigned char *dptr;
774 	ax25_cb *ax25s;
775 	int ret;
776 	struct sk_buff *skbn;
777 
778 
779 	nr_src  = (ax25_address *)(skb->data + 0);
780 	nr_dest = (ax25_address *)(skb->data + 7);
781 
782 	if (ax25 != NULL) {
783 		ret = nr_add_node(nr_src, "", &ax25->dest_addr, ax25->digipeat,
784 				  ax25->ax25_dev->dev, 0,
785 				  sysctl_netrom_obsolescence_count_initialiser);
786 		if (ret)
787 			return ret;
788 	}
789 
790 	if ((dev = nr_dev_get(nr_dest)) != NULL) {	/* Its for me */
791 		if (ax25 == NULL)			/* Its from me */
792 			ret = nr_loopback_queue(skb);
793 		else
794 			ret = nr_rx_frame(skb, dev);
795 		dev_put(dev);
796 		return ret;
797 	}
798 
799 	if (!sysctl_netrom_routing_control && ax25 != NULL)
800 		return 0;
801 
802 	/* Its Time-To-Live has expired */
803 	if (skb->data[14] == 1) {
804 		return 0;
805 	}
806 
807 	nr_node = nr_node_get(nr_dest);
808 	if (nr_node == NULL)
809 		return 0;
810 	nr_node_lock(nr_node);
811 
812 	if (nr_node->which >= nr_node->count) {
813 		nr_node_unlock(nr_node);
814 		nr_node_put(nr_node);
815 		return 0;
816 	}
817 
818 	nr_neigh = nr_node->routes[nr_node->which].neighbour;
819 
820 	if ((dev = nr_dev_first()) == NULL) {
821 		nr_node_unlock(nr_node);
822 		nr_node_put(nr_node);
823 		return 0;
824 	}
825 
826 	/* We are going to change the netrom headers so we should get our
827 	   own skb, we also did not know until now how much header space
828 	   we had to reserve... - RXQ */
829 	if ((skbn=skb_copy_expand(skb, dev->hard_header_len, 0, GFP_ATOMIC)) == NULL) {
830 		nr_node_unlock(nr_node);
831 		nr_node_put(nr_node);
832 		dev_put(dev);
833 		return 0;
834 	}
835 	kfree_skb(skb);
836 	skb=skbn;
837 	skb->data[14]--;
838 
839 	dptr  = skb_push(skb, 1);
840 	*dptr = AX25_P_NETROM;
841 
842 	ax25s = ax25_send_frame(skb, 256, (ax25_address *)dev->dev_addr, &nr_neigh->callsign, nr_neigh->digipeat, nr_neigh->dev);
843 	if (nr_neigh->ax25 && ax25s) {
844 		/* We were already holding this ax25_cb */
845 		ax25_cb_put(ax25s);
846 	}
847 	nr_neigh->ax25 = ax25s;
848 
849 	dev_put(dev);
850 	ret = (nr_neigh->ax25 != NULL);
851 	nr_node_unlock(nr_node);
852 	nr_node_put(nr_node);
853 
854 	return ret;
855 }
856 
857 #ifdef CONFIG_PROC_FS
858 
859 static void *nr_node_start(struct seq_file *seq, loff_t *pos)
860 {
861 	struct nr_node *nr_node;
862 	struct hlist_node *node;
863 	int i = 1;
864 
865 	spin_lock_bh(&nr_node_list_lock);
866 	if (*pos == 0)
867 		return SEQ_START_TOKEN;
868 
869 	nr_node_for_each(nr_node, node, &nr_node_list) {
870 		if (i == *pos)
871 			return nr_node;
872 		++i;
873 	}
874 
875 	return NULL;
876 }
877 
878 static void *nr_node_next(struct seq_file *seq, void *v, loff_t *pos)
879 {
880 	struct hlist_node *node;
881 	++*pos;
882 
883 	node = (v == SEQ_START_TOKEN)
884 		? nr_node_list.first
885 		: ((struct nr_node *)v)->node_node.next;
886 
887 	return hlist_entry(node, struct nr_node, node_node);
888 }
889 
890 static void nr_node_stop(struct seq_file *seq, void *v)
891 {
892 	spin_unlock_bh(&nr_node_list_lock);
893 }
894 
895 static int nr_node_show(struct seq_file *seq, void *v)
896 {
897 	char buf[11];
898 	int i;
899 
900 	if (v == SEQ_START_TOKEN)
901 		seq_puts(seq,
902 			 "callsign  mnemonic w n qual obs neigh qual obs neigh qual obs neigh\n");
903 	else {
904 		struct nr_node *nr_node = v;
905 		nr_node_lock(nr_node);
906 		seq_printf(seq, "%-9s %-7s  %d %d",
907 			ax2asc(buf, &nr_node->callsign),
908 			(nr_node->mnemonic[0] == '\0') ? "*" : nr_node->mnemonic,
909 			nr_node->which + 1,
910 			nr_node->count);
911 
912 		for (i = 0; i < nr_node->count; i++) {
913 			seq_printf(seq, "  %3d   %d %05d",
914 				nr_node->routes[i].quality,
915 				nr_node->routes[i].obs_count,
916 				nr_node->routes[i].neighbour->number);
917 		}
918 		nr_node_unlock(nr_node);
919 
920 		seq_puts(seq, "\n");
921 	}
922 	return 0;
923 }
924 
925 static struct seq_operations nr_node_seqops = {
926 	.start = nr_node_start,
927 	.next = nr_node_next,
928 	.stop = nr_node_stop,
929 	.show = nr_node_show,
930 };
931 
932 static int nr_node_info_open(struct inode *inode, struct file *file)
933 {
934 	return seq_open(file, &nr_node_seqops);
935 }
936 
937 const struct file_operations nr_nodes_fops = {
938 	.owner = THIS_MODULE,
939 	.open = nr_node_info_open,
940 	.read = seq_read,
941 	.llseek = seq_lseek,
942 	.release = seq_release,
943 };
944 
945 static void *nr_neigh_start(struct seq_file *seq, loff_t *pos)
946 {
947 	struct nr_neigh *nr_neigh;
948 	struct hlist_node *node;
949 	int i = 1;
950 
951 	spin_lock_bh(&nr_neigh_list_lock);
952 	if (*pos == 0)
953 		return SEQ_START_TOKEN;
954 
955 	nr_neigh_for_each(nr_neigh, node, &nr_neigh_list) {
956 		if (i == *pos)
957 			return nr_neigh;
958 	}
959 	return NULL;
960 }
961 
962 static void *nr_neigh_next(struct seq_file *seq, void *v, loff_t *pos)
963 {
964 	struct hlist_node *node;
965 	++*pos;
966 
967 	node = (v == SEQ_START_TOKEN)
968 		? nr_neigh_list.first
969 		: ((struct nr_neigh *)v)->neigh_node.next;
970 
971 	return hlist_entry(node, struct nr_neigh, neigh_node);
972 }
973 
974 static void nr_neigh_stop(struct seq_file *seq, void *v)
975 {
976 	spin_unlock_bh(&nr_neigh_list_lock);
977 }
978 
979 static int nr_neigh_show(struct seq_file *seq, void *v)
980 {
981 	char buf[11];
982 	int i;
983 
984 	if (v == SEQ_START_TOKEN)
985 		seq_puts(seq, "addr  callsign  dev  qual lock count failed digipeaters\n");
986 	else {
987 		struct nr_neigh *nr_neigh = v;
988 
989 		seq_printf(seq, "%05d %-9s %-4s  %3d    %d   %3d    %3d",
990 			nr_neigh->number,
991 			ax2asc(buf, &nr_neigh->callsign),
992 			nr_neigh->dev ? nr_neigh->dev->name : "???",
993 			nr_neigh->quality,
994 			nr_neigh->locked,
995 			nr_neigh->count,
996 			nr_neigh->failed);
997 
998 		if (nr_neigh->digipeat != NULL) {
999 			for (i = 0; i < nr_neigh->digipeat->ndigi; i++)
1000 				seq_printf(seq, " %s",
1001 					   ax2asc(buf, &nr_neigh->digipeat->calls[i]));
1002 		}
1003 
1004 		seq_puts(seq, "\n");
1005 	}
1006 	return 0;
1007 }
1008 
1009 static struct seq_operations nr_neigh_seqops = {
1010 	.start = nr_neigh_start,
1011 	.next = nr_neigh_next,
1012 	.stop = nr_neigh_stop,
1013 	.show = nr_neigh_show,
1014 };
1015 
1016 static int nr_neigh_info_open(struct inode *inode, struct file *file)
1017 {
1018 	return seq_open(file, &nr_neigh_seqops);
1019 }
1020 
1021 const struct file_operations nr_neigh_fops = {
1022 	.owner = THIS_MODULE,
1023 	.open = nr_neigh_info_open,
1024 	.read = seq_read,
1025 	.llseek = seq_lseek,
1026 	.release = seq_release,
1027 };
1028 
1029 #endif
1030 
1031 /*
1032  *	Free all memory associated with the nodes and routes lists.
1033  */
1034 void __exit nr_rt_free(void)
1035 {
1036 	struct nr_neigh *s = NULL;
1037 	struct nr_node  *t = NULL;
1038 	struct hlist_node *node, *nodet;
1039 
1040 	spin_lock_bh(&nr_neigh_list_lock);
1041 	spin_lock_bh(&nr_node_list_lock);
1042 	nr_node_for_each_safe(t, node, nodet, &nr_node_list) {
1043 		nr_node_lock(t);
1044 		nr_remove_node_locked(t);
1045 		nr_node_unlock(t);
1046 	}
1047 	nr_neigh_for_each_safe(s, node, nodet, &nr_neigh_list) {
1048 		while(s->count) {
1049 			s->count--;
1050 			nr_neigh_put(s);
1051 		}
1052 		nr_remove_neigh_locked(s);
1053 	}
1054 	spin_unlock_bh(&nr_node_list_lock);
1055 	spin_unlock_bh(&nr_neigh_list_lock);
1056 }
1057