xref: /openbmc/linux/net/core/fib_rules.c (revision 4bce6fce)
1 /*
2  * net/core/fib_rules.c		Generic Routing Rules
3  *
4  *	This program is free software; you can redistribute it and/or
5  *	modify it under the terms of the GNU General Public License as
6  *	published by the Free Software Foundation, version 2.
7  *
8  * Authors:	Thomas Graf <tgraf@suug.ch>
9  */
10 
11 #include <linux/types.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/list.h>
15 #include <linux/module.h>
16 #include <net/net_namespace.h>
17 #include <net/sock.h>
18 #include <net/fib_rules.h>
19 
20 int fib_default_rule_add(struct fib_rules_ops *ops,
21 			 u32 pref, u32 table, u32 flags)
22 {
23 	struct fib_rule *r;
24 
25 	r = kzalloc(ops->rule_size, GFP_KERNEL);
26 	if (r == NULL)
27 		return -ENOMEM;
28 
29 	atomic_set(&r->refcnt, 1);
30 	r->action = FR_ACT_TO_TBL;
31 	r->pref = pref;
32 	r->table = table;
33 	r->flags = flags;
34 	r->fr_net = ops->fro_net;
35 
36 	r->suppress_prefixlen = -1;
37 	r->suppress_ifgroup = -1;
38 
39 	/* The lock is not required here, the list in unreacheable
40 	 * at the moment this function is called */
41 	list_add_tail(&r->list, &ops->rules_list);
42 	return 0;
43 }
44 EXPORT_SYMBOL(fib_default_rule_add);
45 
46 u32 fib_default_rule_pref(struct fib_rules_ops *ops)
47 {
48 	struct list_head *pos;
49 	struct fib_rule *rule;
50 
51 	if (!list_empty(&ops->rules_list)) {
52 		pos = ops->rules_list.next;
53 		if (pos->next != &ops->rules_list) {
54 			rule = list_entry(pos->next, struct fib_rule, list);
55 			if (rule->pref)
56 				return rule->pref - 1;
57 		}
58 	}
59 
60 	return 0;
61 }
62 EXPORT_SYMBOL(fib_default_rule_pref);
63 
64 static void notify_rule_change(int event, struct fib_rule *rule,
65 			       struct fib_rules_ops *ops, struct nlmsghdr *nlh,
66 			       u32 pid);
67 
68 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
69 {
70 	struct fib_rules_ops *ops;
71 
72 	rcu_read_lock();
73 	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
74 		if (ops->family == family) {
75 			if (!try_module_get(ops->owner))
76 				ops = NULL;
77 			rcu_read_unlock();
78 			return ops;
79 		}
80 	}
81 	rcu_read_unlock();
82 
83 	return NULL;
84 }
85 
86 static void rules_ops_put(struct fib_rules_ops *ops)
87 {
88 	if (ops)
89 		module_put(ops->owner);
90 }
91 
92 static void flush_route_cache(struct fib_rules_ops *ops)
93 {
94 	if (ops->flush_cache)
95 		ops->flush_cache(ops);
96 }
97 
98 static int __fib_rules_register(struct fib_rules_ops *ops)
99 {
100 	int err = -EEXIST;
101 	struct fib_rules_ops *o;
102 	struct net *net;
103 
104 	net = ops->fro_net;
105 
106 	if (ops->rule_size < sizeof(struct fib_rule))
107 		return -EINVAL;
108 
109 	if (ops->match == NULL || ops->configure == NULL ||
110 	    ops->compare == NULL || ops->fill == NULL ||
111 	    ops->action == NULL)
112 		return -EINVAL;
113 
114 	spin_lock(&net->rules_mod_lock);
115 	list_for_each_entry(o, &net->rules_ops, list)
116 		if (ops->family == o->family)
117 			goto errout;
118 
119 	list_add_tail_rcu(&ops->list, &net->rules_ops);
120 	err = 0;
121 errout:
122 	spin_unlock(&net->rules_mod_lock);
123 
124 	return err;
125 }
126 
127 struct fib_rules_ops *
128 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
129 {
130 	struct fib_rules_ops *ops;
131 	int err;
132 
133 	ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
134 	if (ops == NULL)
135 		return ERR_PTR(-ENOMEM);
136 
137 	INIT_LIST_HEAD(&ops->rules_list);
138 	ops->fro_net = net;
139 
140 	err = __fib_rules_register(ops);
141 	if (err) {
142 		kfree(ops);
143 		ops = ERR_PTR(err);
144 	}
145 
146 	return ops;
147 }
148 EXPORT_SYMBOL_GPL(fib_rules_register);
149 
150 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
151 {
152 	struct fib_rule *rule, *tmp;
153 
154 	list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
155 		list_del_rcu(&rule->list);
156 		if (ops->delete)
157 			ops->delete(rule);
158 		fib_rule_put(rule);
159 	}
160 }
161 
162 void fib_rules_unregister(struct fib_rules_ops *ops)
163 {
164 	struct net *net = ops->fro_net;
165 
166 	spin_lock(&net->rules_mod_lock);
167 	list_del_rcu(&ops->list);
168 	spin_unlock(&net->rules_mod_lock);
169 
170 	fib_rules_cleanup_ops(ops);
171 	kfree_rcu(ops, rcu);
172 }
173 EXPORT_SYMBOL_GPL(fib_rules_unregister);
174 
175 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
176 			  struct flowi *fl, int flags)
177 {
178 	int ret = 0;
179 
180 	if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
181 		goto out;
182 
183 	if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
184 		goto out;
185 
186 	if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
187 		goto out;
188 
189 	ret = ops->match(rule, fl, flags);
190 out:
191 	return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
192 }
193 
194 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
195 		     int flags, struct fib_lookup_arg *arg)
196 {
197 	struct fib_rule *rule;
198 	int err;
199 
200 	rcu_read_lock();
201 
202 	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
203 jumped:
204 		if (!fib_rule_match(rule, ops, fl, flags))
205 			continue;
206 
207 		if (rule->action == FR_ACT_GOTO) {
208 			struct fib_rule *target;
209 
210 			target = rcu_dereference(rule->ctarget);
211 			if (target == NULL) {
212 				continue;
213 			} else {
214 				rule = target;
215 				goto jumped;
216 			}
217 		} else if (rule->action == FR_ACT_NOP)
218 			continue;
219 		else
220 			err = ops->action(rule, fl, flags, arg);
221 
222 		if (!err && ops->suppress && ops->suppress(rule, arg))
223 			continue;
224 
225 		if (err != -EAGAIN) {
226 			if ((arg->flags & FIB_LOOKUP_NOREF) ||
227 			    likely(atomic_inc_not_zero(&rule->refcnt))) {
228 				arg->rule = rule;
229 				goto out;
230 			}
231 			break;
232 		}
233 	}
234 
235 	err = -ESRCH;
236 out:
237 	rcu_read_unlock();
238 
239 	return err;
240 }
241 EXPORT_SYMBOL_GPL(fib_rules_lookup);
242 
243 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
244 			    struct fib_rules_ops *ops)
245 {
246 	int err = -EINVAL;
247 
248 	if (frh->src_len)
249 		if (tb[FRA_SRC] == NULL ||
250 		    frh->src_len > (ops->addr_size * 8) ||
251 		    nla_len(tb[FRA_SRC]) != ops->addr_size)
252 			goto errout;
253 
254 	if (frh->dst_len)
255 		if (tb[FRA_DST] == NULL ||
256 		    frh->dst_len > (ops->addr_size * 8) ||
257 		    nla_len(tb[FRA_DST]) != ops->addr_size)
258 			goto errout;
259 
260 	err = 0;
261 errout:
262 	return err;
263 }
264 
265 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
266 {
267 	struct net *net = sock_net(skb->sk);
268 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
269 	struct fib_rules_ops *ops = NULL;
270 	struct fib_rule *rule, *r, *last = NULL;
271 	struct nlattr *tb[FRA_MAX+1];
272 	int err = -EINVAL, unresolved = 0;
273 
274 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
275 		goto errout;
276 
277 	ops = lookup_rules_ops(net, frh->family);
278 	if (ops == NULL) {
279 		err = -EAFNOSUPPORT;
280 		goto errout;
281 	}
282 
283 	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
284 	if (err < 0)
285 		goto errout;
286 
287 	err = validate_rulemsg(frh, tb, ops);
288 	if (err < 0)
289 		goto errout;
290 
291 	rule = kzalloc(ops->rule_size, GFP_KERNEL);
292 	if (rule == NULL) {
293 		err = -ENOMEM;
294 		goto errout;
295 	}
296 	rule->fr_net = net;
297 
298 	if (tb[FRA_PRIORITY])
299 		rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
300 
301 	if (tb[FRA_IIFNAME]) {
302 		struct net_device *dev;
303 
304 		rule->iifindex = -1;
305 		nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
306 		dev = __dev_get_by_name(net, rule->iifname);
307 		if (dev)
308 			rule->iifindex = dev->ifindex;
309 	}
310 
311 	if (tb[FRA_OIFNAME]) {
312 		struct net_device *dev;
313 
314 		rule->oifindex = -1;
315 		nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
316 		dev = __dev_get_by_name(net, rule->oifname);
317 		if (dev)
318 			rule->oifindex = dev->ifindex;
319 	}
320 
321 	if (tb[FRA_FWMARK]) {
322 		rule->mark = nla_get_u32(tb[FRA_FWMARK]);
323 		if (rule->mark)
324 			/* compatibility: if the mark value is non-zero all bits
325 			 * are compared unless a mask is explicitly specified.
326 			 */
327 			rule->mark_mask = 0xFFFFFFFF;
328 	}
329 
330 	if (tb[FRA_FWMASK])
331 		rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
332 
333 	rule->action = frh->action;
334 	rule->flags = frh->flags;
335 	rule->table = frh_get_table(frh, tb);
336 	if (tb[FRA_SUPPRESS_PREFIXLEN])
337 		rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
338 	else
339 		rule->suppress_prefixlen = -1;
340 
341 	if (tb[FRA_SUPPRESS_IFGROUP])
342 		rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
343 	else
344 		rule->suppress_ifgroup = -1;
345 
346 	if (!tb[FRA_PRIORITY] && ops->default_pref)
347 		rule->pref = ops->default_pref(ops);
348 
349 	err = -EINVAL;
350 	if (tb[FRA_GOTO]) {
351 		if (rule->action != FR_ACT_GOTO)
352 			goto errout_free;
353 
354 		rule->target = nla_get_u32(tb[FRA_GOTO]);
355 		/* Backward jumps are prohibited to avoid endless loops */
356 		if (rule->target <= rule->pref)
357 			goto errout_free;
358 
359 		list_for_each_entry(r, &ops->rules_list, list) {
360 			if (r->pref == rule->target) {
361 				RCU_INIT_POINTER(rule->ctarget, r);
362 				break;
363 			}
364 		}
365 
366 		if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
367 			unresolved = 1;
368 	} else if (rule->action == FR_ACT_GOTO)
369 		goto errout_free;
370 
371 	err = ops->configure(rule, skb, frh, tb);
372 	if (err < 0)
373 		goto errout_free;
374 
375 	list_for_each_entry(r, &ops->rules_list, list) {
376 		if (r->pref > rule->pref)
377 			break;
378 		last = r;
379 	}
380 
381 	fib_rule_get(rule);
382 
383 	if (last)
384 		list_add_rcu(&rule->list, &last->list);
385 	else
386 		list_add_rcu(&rule->list, &ops->rules_list);
387 
388 	if (ops->unresolved_rules) {
389 		/*
390 		 * There are unresolved goto rules in the list, check if
391 		 * any of them are pointing to this new rule.
392 		 */
393 		list_for_each_entry(r, &ops->rules_list, list) {
394 			if (r->action == FR_ACT_GOTO &&
395 			    r->target == rule->pref &&
396 			    rtnl_dereference(r->ctarget) == NULL) {
397 				rcu_assign_pointer(r->ctarget, rule);
398 				if (--ops->unresolved_rules == 0)
399 					break;
400 			}
401 		}
402 	}
403 
404 	if (rule->action == FR_ACT_GOTO)
405 		ops->nr_goto_rules++;
406 
407 	if (unresolved)
408 		ops->unresolved_rules++;
409 
410 	notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
411 	flush_route_cache(ops);
412 	rules_ops_put(ops);
413 	return 0;
414 
415 errout_free:
416 	kfree(rule);
417 errout:
418 	rules_ops_put(ops);
419 	return err;
420 }
421 
422 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
423 {
424 	struct net *net = sock_net(skb->sk);
425 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
426 	struct fib_rules_ops *ops = NULL;
427 	struct fib_rule *rule, *tmp;
428 	struct nlattr *tb[FRA_MAX+1];
429 	int err = -EINVAL;
430 
431 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
432 		goto errout;
433 
434 	ops = lookup_rules_ops(net, frh->family);
435 	if (ops == NULL) {
436 		err = -EAFNOSUPPORT;
437 		goto errout;
438 	}
439 
440 	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
441 	if (err < 0)
442 		goto errout;
443 
444 	err = validate_rulemsg(frh, tb, ops);
445 	if (err < 0)
446 		goto errout;
447 
448 	list_for_each_entry(rule, &ops->rules_list, list) {
449 		if (frh->action && (frh->action != rule->action))
450 			continue;
451 
452 		if (frh_get_table(frh, tb) &&
453 		    (frh_get_table(frh, tb) != rule->table))
454 			continue;
455 
456 		if (tb[FRA_PRIORITY] &&
457 		    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
458 			continue;
459 
460 		if (tb[FRA_IIFNAME] &&
461 		    nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
462 			continue;
463 
464 		if (tb[FRA_OIFNAME] &&
465 		    nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
466 			continue;
467 
468 		if (tb[FRA_FWMARK] &&
469 		    (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
470 			continue;
471 
472 		if (tb[FRA_FWMASK] &&
473 		    (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
474 			continue;
475 
476 		if (!ops->compare(rule, frh, tb))
477 			continue;
478 
479 		if (rule->flags & FIB_RULE_PERMANENT) {
480 			err = -EPERM;
481 			goto errout;
482 		}
483 
484 		if (ops->delete) {
485 			err = ops->delete(rule);
486 			if (err)
487 				goto errout;
488 		}
489 
490 		list_del_rcu(&rule->list);
491 
492 		if (rule->action == FR_ACT_GOTO) {
493 			ops->nr_goto_rules--;
494 			if (rtnl_dereference(rule->ctarget) == NULL)
495 				ops->unresolved_rules--;
496 		}
497 
498 		/*
499 		 * Check if this rule is a target to any of them. If so,
500 		 * disable them. As this operation is eventually very
501 		 * expensive, it is only performed if goto rules have
502 		 * actually been added.
503 		 */
504 		if (ops->nr_goto_rules > 0) {
505 			list_for_each_entry(tmp, &ops->rules_list, list) {
506 				if (rtnl_dereference(tmp->ctarget) == rule) {
507 					RCU_INIT_POINTER(tmp->ctarget, NULL);
508 					ops->unresolved_rules++;
509 				}
510 			}
511 		}
512 
513 		notify_rule_change(RTM_DELRULE, rule, ops, nlh,
514 				   NETLINK_CB(skb).portid);
515 		fib_rule_put(rule);
516 		flush_route_cache(ops);
517 		rules_ops_put(ops);
518 		return 0;
519 	}
520 
521 	err = -ENOENT;
522 errout:
523 	rules_ops_put(ops);
524 	return err;
525 }
526 
527 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
528 					 struct fib_rule *rule)
529 {
530 	size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
531 			 + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
532 			 + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
533 			 + nla_total_size(4) /* FRA_PRIORITY */
534 			 + nla_total_size(4) /* FRA_TABLE */
535 			 + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
536 			 + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
537 			 + nla_total_size(4) /* FRA_FWMARK */
538 			 + nla_total_size(4); /* FRA_FWMASK */
539 
540 	if (ops->nlmsg_payload)
541 		payload += ops->nlmsg_payload(rule);
542 
543 	return payload;
544 }
545 
546 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
547 			    u32 pid, u32 seq, int type, int flags,
548 			    struct fib_rules_ops *ops)
549 {
550 	struct nlmsghdr *nlh;
551 	struct fib_rule_hdr *frh;
552 
553 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
554 	if (nlh == NULL)
555 		return -EMSGSIZE;
556 
557 	frh = nlmsg_data(nlh);
558 	frh->family = ops->family;
559 	frh->table = rule->table;
560 	if (nla_put_u32(skb, FRA_TABLE, rule->table))
561 		goto nla_put_failure;
562 	if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
563 		goto nla_put_failure;
564 	frh->res1 = 0;
565 	frh->res2 = 0;
566 	frh->action = rule->action;
567 	frh->flags = rule->flags;
568 
569 	if (rule->action == FR_ACT_GOTO &&
570 	    rcu_access_pointer(rule->ctarget) == NULL)
571 		frh->flags |= FIB_RULE_UNRESOLVED;
572 
573 	if (rule->iifname[0]) {
574 		if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
575 			goto nla_put_failure;
576 		if (rule->iifindex == -1)
577 			frh->flags |= FIB_RULE_IIF_DETACHED;
578 	}
579 
580 	if (rule->oifname[0]) {
581 		if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
582 			goto nla_put_failure;
583 		if (rule->oifindex == -1)
584 			frh->flags |= FIB_RULE_OIF_DETACHED;
585 	}
586 
587 	if ((rule->pref &&
588 	     nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
589 	    (rule->mark &&
590 	     nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
591 	    ((rule->mark_mask || rule->mark) &&
592 	     nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
593 	    (rule->target &&
594 	     nla_put_u32(skb, FRA_GOTO, rule->target)))
595 		goto nla_put_failure;
596 
597 	if (rule->suppress_ifgroup != -1) {
598 		if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
599 			goto nla_put_failure;
600 	}
601 
602 	if (ops->fill(rule, skb, frh) < 0)
603 		goto nla_put_failure;
604 
605 	nlmsg_end(skb, nlh);
606 	return 0;
607 
608 nla_put_failure:
609 	nlmsg_cancel(skb, nlh);
610 	return -EMSGSIZE;
611 }
612 
613 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
614 		      struct fib_rules_ops *ops)
615 {
616 	int idx = 0;
617 	struct fib_rule *rule;
618 
619 	rcu_read_lock();
620 	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
621 		if (idx < cb->args[1])
622 			goto skip;
623 
624 		if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
625 				     cb->nlh->nlmsg_seq, RTM_NEWRULE,
626 				     NLM_F_MULTI, ops) < 0)
627 			break;
628 skip:
629 		idx++;
630 	}
631 	rcu_read_unlock();
632 	cb->args[1] = idx;
633 	rules_ops_put(ops);
634 
635 	return skb->len;
636 }
637 
638 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
639 {
640 	struct net *net = sock_net(skb->sk);
641 	struct fib_rules_ops *ops;
642 	int idx = 0, family;
643 
644 	family = rtnl_msg_family(cb->nlh);
645 	if (family != AF_UNSPEC) {
646 		/* Protocol specific dump request */
647 		ops = lookup_rules_ops(net, family);
648 		if (ops == NULL)
649 			return -EAFNOSUPPORT;
650 
651 		return dump_rules(skb, cb, ops);
652 	}
653 
654 	rcu_read_lock();
655 	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
656 		if (idx < cb->args[0] || !try_module_get(ops->owner))
657 			goto skip;
658 
659 		if (dump_rules(skb, cb, ops) < 0)
660 			break;
661 
662 		cb->args[1] = 0;
663 skip:
664 		idx++;
665 	}
666 	rcu_read_unlock();
667 	cb->args[0] = idx;
668 
669 	return skb->len;
670 }
671 
672 static void notify_rule_change(int event, struct fib_rule *rule,
673 			       struct fib_rules_ops *ops, struct nlmsghdr *nlh,
674 			       u32 pid)
675 {
676 	struct net *net;
677 	struct sk_buff *skb;
678 	int err = -ENOBUFS;
679 
680 	net = ops->fro_net;
681 	skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
682 	if (skb == NULL)
683 		goto errout;
684 
685 	err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
686 	if (err < 0) {
687 		/* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
688 		WARN_ON(err == -EMSGSIZE);
689 		kfree_skb(skb);
690 		goto errout;
691 	}
692 
693 	rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
694 	return;
695 errout:
696 	if (err < 0)
697 		rtnl_set_sk_err(net, ops->nlgroup, err);
698 }
699 
700 static void attach_rules(struct list_head *rules, struct net_device *dev)
701 {
702 	struct fib_rule *rule;
703 
704 	list_for_each_entry(rule, rules, list) {
705 		if (rule->iifindex == -1 &&
706 		    strcmp(dev->name, rule->iifname) == 0)
707 			rule->iifindex = dev->ifindex;
708 		if (rule->oifindex == -1 &&
709 		    strcmp(dev->name, rule->oifname) == 0)
710 			rule->oifindex = dev->ifindex;
711 	}
712 }
713 
714 static void detach_rules(struct list_head *rules, struct net_device *dev)
715 {
716 	struct fib_rule *rule;
717 
718 	list_for_each_entry(rule, rules, list) {
719 		if (rule->iifindex == dev->ifindex)
720 			rule->iifindex = -1;
721 		if (rule->oifindex == dev->ifindex)
722 			rule->oifindex = -1;
723 	}
724 }
725 
726 
727 static int fib_rules_event(struct notifier_block *this, unsigned long event,
728 			   void *ptr)
729 {
730 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
731 	struct net *net = dev_net(dev);
732 	struct fib_rules_ops *ops;
733 
734 	ASSERT_RTNL();
735 
736 	switch (event) {
737 	case NETDEV_REGISTER:
738 		list_for_each_entry(ops, &net->rules_ops, list)
739 			attach_rules(&ops->rules_list, dev);
740 		break;
741 
742 	case NETDEV_CHANGENAME:
743 		list_for_each_entry(ops, &net->rules_ops, list) {
744 			detach_rules(&ops->rules_list, dev);
745 			attach_rules(&ops->rules_list, dev);
746 		}
747 		break;
748 
749 	case NETDEV_UNREGISTER:
750 		list_for_each_entry(ops, &net->rules_ops, list)
751 			detach_rules(&ops->rules_list, dev);
752 		break;
753 	}
754 
755 	return NOTIFY_DONE;
756 }
757 
758 static struct notifier_block fib_rules_notifier = {
759 	.notifier_call = fib_rules_event,
760 };
761 
762 static int __net_init fib_rules_net_init(struct net *net)
763 {
764 	INIT_LIST_HEAD(&net->rules_ops);
765 	spin_lock_init(&net->rules_mod_lock);
766 	return 0;
767 }
768 
769 static struct pernet_operations fib_rules_net_ops = {
770 	.init = fib_rules_net_init,
771 };
772 
773 static int __init fib_rules_init(void)
774 {
775 	int err;
776 	rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
777 	rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
778 	rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
779 
780 	err = register_pernet_subsys(&fib_rules_net_ops);
781 	if (err < 0)
782 		goto fail;
783 
784 	err = register_netdevice_notifier(&fib_rules_notifier);
785 	if (err < 0)
786 		goto fail_unregister;
787 
788 	return 0;
789 
790 fail_unregister:
791 	unregister_pernet_subsys(&fib_rules_net_ops);
792 fail:
793 	rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
794 	rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
795 	rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
796 	return err;
797 }
798 
799 subsys_initcall(fib_rules_init);
800