xref: /openbmc/linux/net/core/fib_rules.c (revision 81d67439)
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 <net/net_namespace.h>
16 #include <net/sock.h>
17 #include <net/fib_rules.h>
18 
19 int fib_default_rule_add(struct fib_rules_ops *ops,
20 			 u32 pref, u32 table, u32 flags)
21 {
22 	struct fib_rule *r;
23 
24 	r = kzalloc(ops->rule_size, GFP_KERNEL);
25 	if (r == NULL)
26 		return -ENOMEM;
27 
28 	atomic_set(&r->refcnt, 1);
29 	r->action = FR_ACT_TO_TBL;
30 	r->pref = pref;
31 	r->table = table;
32 	r->flags = flags;
33 	r->fr_net = hold_net(ops->fro_net);
34 
35 	/* The lock is not required here, the list in unreacheable
36 	 * at the moment this function is called */
37 	list_add_tail(&r->list, &ops->rules_list);
38 	return 0;
39 }
40 EXPORT_SYMBOL(fib_default_rule_add);
41 
42 u32 fib_default_rule_pref(struct fib_rules_ops *ops)
43 {
44 	struct list_head *pos;
45 	struct fib_rule *rule;
46 
47 	if (!list_empty(&ops->rules_list)) {
48 		pos = ops->rules_list.next;
49 		if (pos->next != &ops->rules_list) {
50 			rule = list_entry(pos->next, struct fib_rule, list);
51 			if (rule->pref)
52 				return rule->pref - 1;
53 		}
54 	}
55 
56 	return 0;
57 }
58 EXPORT_SYMBOL(fib_default_rule_pref);
59 
60 static void notify_rule_change(int event, struct fib_rule *rule,
61 			       struct fib_rules_ops *ops, struct nlmsghdr *nlh,
62 			       u32 pid);
63 
64 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
65 {
66 	struct fib_rules_ops *ops;
67 
68 	rcu_read_lock();
69 	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
70 		if (ops->family == family) {
71 			if (!try_module_get(ops->owner))
72 				ops = NULL;
73 			rcu_read_unlock();
74 			return ops;
75 		}
76 	}
77 	rcu_read_unlock();
78 
79 	return NULL;
80 }
81 
82 static void rules_ops_put(struct fib_rules_ops *ops)
83 {
84 	if (ops)
85 		module_put(ops->owner);
86 }
87 
88 static void flush_route_cache(struct fib_rules_ops *ops)
89 {
90 	if (ops->flush_cache)
91 		ops->flush_cache(ops);
92 }
93 
94 static int __fib_rules_register(struct fib_rules_ops *ops)
95 {
96 	int err = -EEXIST;
97 	struct fib_rules_ops *o;
98 	struct net *net;
99 
100 	net = ops->fro_net;
101 
102 	if (ops->rule_size < sizeof(struct fib_rule))
103 		return -EINVAL;
104 
105 	if (ops->match == NULL || ops->configure == NULL ||
106 	    ops->compare == NULL || ops->fill == NULL ||
107 	    ops->action == NULL)
108 		return -EINVAL;
109 
110 	spin_lock(&net->rules_mod_lock);
111 	list_for_each_entry(o, &net->rules_ops, list)
112 		if (ops->family == o->family)
113 			goto errout;
114 
115 	hold_net(net);
116 	list_add_tail_rcu(&ops->list, &net->rules_ops);
117 	err = 0;
118 errout:
119 	spin_unlock(&net->rules_mod_lock);
120 
121 	return err;
122 }
123 
124 struct fib_rules_ops *
125 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
126 {
127 	struct fib_rules_ops *ops;
128 	int err;
129 
130 	ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
131 	if (ops == NULL)
132 		return ERR_PTR(-ENOMEM);
133 
134 	INIT_LIST_HEAD(&ops->rules_list);
135 	ops->fro_net = net;
136 
137 	err = __fib_rules_register(ops);
138 	if (err) {
139 		kfree(ops);
140 		ops = ERR_PTR(err);
141 	}
142 
143 	return ops;
144 }
145 EXPORT_SYMBOL_GPL(fib_rules_register);
146 
147 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
148 {
149 	struct fib_rule *rule, *tmp;
150 
151 	list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
152 		list_del_rcu(&rule->list);
153 		fib_rule_put(rule);
154 	}
155 }
156 
157 static void fib_rules_put_rcu(struct rcu_head *head)
158 {
159 	struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
160 	struct net *net = ops->fro_net;
161 
162 	release_net(net);
163 	kfree(ops);
164 }
165 
166 void fib_rules_unregister(struct fib_rules_ops *ops)
167 {
168 	struct net *net = ops->fro_net;
169 
170 	spin_lock(&net->rules_mod_lock);
171 	list_del_rcu(&ops->list);
172 	fib_rules_cleanup_ops(ops);
173 	spin_unlock(&net->rules_mod_lock);
174 
175 	call_rcu(&ops->rcu, fib_rules_put_rcu);
176 }
177 EXPORT_SYMBOL_GPL(fib_rules_unregister);
178 
179 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
180 			  struct flowi *fl, int flags)
181 {
182 	int ret = 0;
183 
184 	if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
185 		goto out;
186 
187 	if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
188 		goto out;
189 
190 	if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
191 		goto out;
192 
193 	ret = ops->match(rule, fl, flags);
194 out:
195 	return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
196 }
197 
198 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
199 		     int flags, struct fib_lookup_arg *arg)
200 {
201 	struct fib_rule *rule;
202 	int err;
203 
204 	rcu_read_lock();
205 
206 	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
207 jumped:
208 		if (!fib_rule_match(rule, ops, fl, flags))
209 			continue;
210 
211 		if (rule->action == FR_ACT_GOTO) {
212 			struct fib_rule *target;
213 
214 			target = rcu_dereference(rule->ctarget);
215 			if (target == NULL) {
216 				continue;
217 			} else {
218 				rule = target;
219 				goto jumped;
220 			}
221 		} else if (rule->action == FR_ACT_NOP)
222 			continue;
223 		else
224 			err = ops->action(rule, fl, flags, arg);
225 
226 		if (err != -EAGAIN) {
227 			if ((arg->flags & FIB_LOOKUP_NOREF) ||
228 			    likely(atomic_inc_not_zero(&rule->refcnt))) {
229 				arg->rule = rule;
230 				goto out;
231 			}
232 			break;
233 		}
234 	}
235 
236 	err = -ESRCH;
237 out:
238 	rcu_read_unlock();
239 
240 	return err;
241 }
242 EXPORT_SYMBOL_GPL(fib_rules_lookup);
243 
244 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
245 			    struct fib_rules_ops *ops)
246 {
247 	int err = -EINVAL;
248 
249 	if (frh->src_len)
250 		if (tb[FRA_SRC] == NULL ||
251 		    frh->src_len > (ops->addr_size * 8) ||
252 		    nla_len(tb[FRA_SRC]) != ops->addr_size)
253 			goto errout;
254 
255 	if (frh->dst_len)
256 		if (tb[FRA_DST] == NULL ||
257 		    frh->dst_len > (ops->addr_size * 8) ||
258 		    nla_len(tb[FRA_DST]) != ops->addr_size)
259 			goto errout;
260 
261 	err = 0;
262 errout:
263 	return err;
264 }
265 
266 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
267 {
268 	struct net *net = sock_net(skb->sk);
269 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
270 	struct fib_rules_ops *ops = NULL;
271 	struct fib_rule *rule, *r, *last = NULL;
272 	struct nlattr *tb[FRA_MAX+1];
273 	int err = -EINVAL, unresolved = 0;
274 
275 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
276 		goto errout;
277 
278 	ops = lookup_rules_ops(net, frh->family);
279 	if (ops == NULL) {
280 		err = -EAFNOSUPPORT;
281 		goto errout;
282 	}
283 
284 	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
285 	if (err < 0)
286 		goto errout;
287 
288 	err = validate_rulemsg(frh, tb, ops);
289 	if (err < 0)
290 		goto errout;
291 
292 	rule = kzalloc(ops->rule_size, GFP_KERNEL);
293 	if (rule == NULL) {
294 		err = -ENOMEM;
295 		goto errout;
296 	}
297 	rule->fr_net = hold_net(net);
298 
299 	if (tb[FRA_PRIORITY])
300 		rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
301 
302 	if (tb[FRA_IIFNAME]) {
303 		struct net_device *dev;
304 
305 		rule->iifindex = -1;
306 		nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
307 		dev = __dev_get_by_name(net, rule->iifname);
308 		if (dev)
309 			rule->iifindex = dev->ifindex;
310 	}
311 
312 	if (tb[FRA_OIFNAME]) {
313 		struct net_device *dev;
314 
315 		rule->oifindex = -1;
316 		nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
317 		dev = __dev_get_by_name(net, rule->oifname);
318 		if (dev)
319 			rule->oifindex = dev->ifindex;
320 	}
321 
322 	if (tb[FRA_FWMARK]) {
323 		rule->mark = nla_get_u32(tb[FRA_FWMARK]);
324 		if (rule->mark)
325 			/* compatibility: if the mark value is non-zero all bits
326 			 * are compared unless a mask is explicitly specified.
327 			 */
328 			rule->mark_mask = 0xFFFFFFFF;
329 	}
330 
331 	if (tb[FRA_FWMASK])
332 		rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
333 
334 	rule->action = frh->action;
335 	rule->flags = frh->flags;
336 	rule->table = frh_get_table(frh, tb);
337 
338 	if (!tb[FRA_PRIORITY] && ops->default_pref)
339 		rule->pref = ops->default_pref(ops);
340 
341 	err = -EINVAL;
342 	if (tb[FRA_GOTO]) {
343 		if (rule->action != FR_ACT_GOTO)
344 			goto errout_free;
345 
346 		rule->target = nla_get_u32(tb[FRA_GOTO]);
347 		/* Backward jumps are prohibited to avoid endless loops */
348 		if (rule->target <= rule->pref)
349 			goto errout_free;
350 
351 		list_for_each_entry(r, &ops->rules_list, list) {
352 			if (r->pref == rule->target) {
353 				RCU_INIT_POINTER(rule->ctarget, r);
354 				break;
355 			}
356 		}
357 
358 		if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
359 			unresolved = 1;
360 	} else if (rule->action == FR_ACT_GOTO)
361 		goto errout_free;
362 
363 	err = ops->configure(rule, skb, frh, tb);
364 	if (err < 0)
365 		goto errout_free;
366 
367 	list_for_each_entry(r, &ops->rules_list, list) {
368 		if (r->pref > rule->pref)
369 			break;
370 		last = r;
371 	}
372 
373 	fib_rule_get(rule);
374 
375 	if (last)
376 		list_add_rcu(&rule->list, &last->list);
377 	else
378 		list_add_rcu(&rule->list, &ops->rules_list);
379 
380 	if (ops->unresolved_rules) {
381 		/*
382 		 * There are unresolved goto rules in the list, check if
383 		 * any of them are pointing to this new rule.
384 		 */
385 		list_for_each_entry(r, &ops->rules_list, list) {
386 			if (r->action == FR_ACT_GOTO &&
387 			    r->target == rule->pref) {
388 				BUG_ON(rtnl_dereference(r->ctarget) != NULL);
389 				rcu_assign_pointer(r->ctarget, rule);
390 				if (--ops->unresolved_rules == 0)
391 					break;
392 			}
393 		}
394 	}
395 
396 	if (rule->action == FR_ACT_GOTO)
397 		ops->nr_goto_rules++;
398 
399 	if (unresolved)
400 		ops->unresolved_rules++;
401 
402 	notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid);
403 	flush_route_cache(ops);
404 	rules_ops_put(ops);
405 	return 0;
406 
407 errout_free:
408 	release_net(rule->fr_net);
409 	kfree(rule);
410 errout:
411 	rules_ops_put(ops);
412 	return err;
413 }
414 
415 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
416 {
417 	struct net *net = sock_net(skb->sk);
418 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
419 	struct fib_rules_ops *ops = NULL;
420 	struct fib_rule *rule, *tmp;
421 	struct nlattr *tb[FRA_MAX+1];
422 	int err = -EINVAL;
423 
424 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
425 		goto errout;
426 
427 	ops = lookup_rules_ops(net, frh->family);
428 	if (ops == NULL) {
429 		err = -EAFNOSUPPORT;
430 		goto errout;
431 	}
432 
433 	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
434 	if (err < 0)
435 		goto errout;
436 
437 	err = validate_rulemsg(frh, tb, ops);
438 	if (err < 0)
439 		goto errout;
440 
441 	list_for_each_entry(rule, &ops->rules_list, list) {
442 		if (frh->action && (frh->action != rule->action))
443 			continue;
444 
445 		if (frh->table && (frh_get_table(frh, tb) != rule->table))
446 			continue;
447 
448 		if (tb[FRA_PRIORITY] &&
449 		    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
450 			continue;
451 
452 		if (tb[FRA_IIFNAME] &&
453 		    nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
454 			continue;
455 
456 		if (tb[FRA_OIFNAME] &&
457 		    nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
458 			continue;
459 
460 		if (tb[FRA_FWMARK] &&
461 		    (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
462 			continue;
463 
464 		if (tb[FRA_FWMASK] &&
465 		    (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
466 			continue;
467 
468 		if (!ops->compare(rule, frh, tb))
469 			continue;
470 
471 		if (rule->flags & FIB_RULE_PERMANENT) {
472 			err = -EPERM;
473 			goto errout;
474 		}
475 
476 		list_del_rcu(&rule->list);
477 
478 		if (rule->action == FR_ACT_GOTO)
479 			ops->nr_goto_rules--;
480 
481 		/*
482 		 * Check if this rule is a target to any of them. If so,
483 		 * disable them. As this operation is eventually very
484 		 * expensive, it is only performed if goto rules have
485 		 * actually been added.
486 		 */
487 		if (ops->nr_goto_rules > 0) {
488 			list_for_each_entry(tmp, &ops->rules_list, list) {
489 				if (rtnl_dereference(tmp->ctarget) == rule) {
490 					rcu_assign_pointer(tmp->ctarget, NULL);
491 					ops->unresolved_rules++;
492 				}
493 			}
494 		}
495 
496 		notify_rule_change(RTM_DELRULE, rule, ops, nlh,
497 				   NETLINK_CB(skb).pid);
498 		fib_rule_put(rule);
499 		flush_route_cache(ops);
500 		rules_ops_put(ops);
501 		return 0;
502 	}
503 
504 	err = -ENOENT;
505 errout:
506 	rules_ops_put(ops);
507 	return err;
508 }
509 
510 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
511 					 struct fib_rule *rule)
512 {
513 	size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
514 			 + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
515 			 + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
516 			 + nla_total_size(4) /* FRA_PRIORITY */
517 			 + nla_total_size(4) /* FRA_TABLE */
518 			 + nla_total_size(4) /* FRA_FWMARK */
519 			 + nla_total_size(4); /* FRA_FWMASK */
520 
521 	if (ops->nlmsg_payload)
522 		payload += ops->nlmsg_payload(rule);
523 
524 	return payload;
525 }
526 
527 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
528 			    u32 pid, u32 seq, int type, int flags,
529 			    struct fib_rules_ops *ops)
530 {
531 	struct nlmsghdr *nlh;
532 	struct fib_rule_hdr *frh;
533 
534 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
535 	if (nlh == NULL)
536 		return -EMSGSIZE;
537 
538 	frh = nlmsg_data(nlh);
539 	frh->family = ops->family;
540 	frh->table = rule->table;
541 	NLA_PUT_U32(skb, FRA_TABLE, rule->table);
542 	frh->res1 = 0;
543 	frh->res2 = 0;
544 	frh->action = rule->action;
545 	frh->flags = rule->flags;
546 
547 	if (rule->action == FR_ACT_GOTO &&
548 	    rcu_dereference_raw(rule->ctarget) == NULL)
549 		frh->flags |= FIB_RULE_UNRESOLVED;
550 
551 	if (rule->iifname[0]) {
552 		NLA_PUT_STRING(skb, FRA_IIFNAME, rule->iifname);
553 
554 		if (rule->iifindex == -1)
555 			frh->flags |= FIB_RULE_IIF_DETACHED;
556 	}
557 
558 	if (rule->oifname[0]) {
559 		NLA_PUT_STRING(skb, FRA_OIFNAME, rule->oifname);
560 
561 		if (rule->oifindex == -1)
562 			frh->flags |= FIB_RULE_OIF_DETACHED;
563 	}
564 
565 	if (rule->pref)
566 		NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);
567 
568 	if (rule->mark)
569 		NLA_PUT_U32(skb, FRA_FWMARK, rule->mark);
570 
571 	if (rule->mark_mask || rule->mark)
572 		NLA_PUT_U32(skb, FRA_FWMASK, rule->mark_mask);
573 
574 	if (rule->target)
575 		NLA_PUT_U32(skb, FRA_GOTO, rule->target);
576 
577 	if (ops->fill(rule, skb, frh) < 0)
578 		goto nla_put_failure;
579 
580 	return nlmsg_end(skb, nlh);
581 
582 nla_put_failure:
583 	nlmsg_cancel(skb, nlh);
584 	return -EMSGSIZE;
585 }
586 
587 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
588 		      struct fib_rules_ops *ops)
589 {
590 	int idx = 0;
591 	struct fib_rule *rule;
592 
593 	rcu_read_lock();
594 	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
595 		if (idx < cb->args[1])
596 			goto skip;
597 
598 		if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid,
599 				     cb->nlh->nlmsg_seq, RTM_NEWRULE,
600 				     NLM_F_MULTI, ops) < 0)
601 			break;
602 skip:
603 		idx++;
604 	}
605 	rcu_read_unlock();
606 	cb->args[1] = idx;
607 	rules_ops_put(ops);
608 
609 	return skb->len;
610 }
611 
612 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
613 {
614 	struct net *net = sock_net(skb->sk);
615 	struct fib_rules_ops *ops;
616 	int idx = 0, family;
617 
618 	family = rtnl_msg_family(cb->nlh);
619 	if (family != AF_UNSPEC) {
620 		/* Protocol specific dump request */
621 		ops = lookup_rules_ops(net, family);
622 		if (ops == NULL)
623 			return -EAFNOSUPPORT;
624 
625 		return dump_rules(skb, cb, ops);
626 	}
627 
628 	rcu_read_lock();
629 	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
630 		if (idx < cb->args[0] || !try_module_get(ops->owner))
631 			goto skip;
632 
633 		if (dump_rules(skb, cb, ops) < 0)
634 			break;
635 
636 		cb->args[1] = 0;
637 skip:
638 		idx++;
639 	}
640 	rcu_read_unlock();
641 	cb->args[0] = idx;
642 
643 	return skb->len;
644 }
645 
646 static void notify_rule_change(int event, struct fib_rule *rule,
647 			       struct fib_rules_ops *ops, struct nlmsghdr *nlh,
648 			       u32 pid)
649 {
650 	struct net *net;
651 	struct sk_buff *skb;
652 	int err = -ENOBUFS;
653 
654 	net = ops->fro_net;
655 	skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
656 	if (skb == NULL)
657 		goto errout;
658 
659 	err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
660 	if (err < 0) {
661 		/* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
662 		WARN_ON(err == -EMSGSIZE);
663 		kfree_skb(skb);
664 		goto errout;
665 	}
666 
667 	rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
668 	return;
669 errout:
670 	if (err < 0)
671 		rtnl_set_sk_err(net, ops->nlgroup, err);
672 }
673 
674 static void attach_rules(struct list_head *rules, struct net_device *dev)
675 {
676 	struct fib_rule *rule;
677 
678 	list_for_each_entry(rule, rules, list) {
679 		if (rule->iifindex == -1 &&
680 		    strcmp(dev->name, rule->iifname) == 0)
681 			rule->iifindex = dev->ifindex;
682 		if (rule->oifindex == -1 &&
683 		    strcmp(dev->name, rule->oifname) == 0)
684 			rule->oifindex = dev->ifindex;
685 	}
686 }
687 
688 static void detach_rules(struct list_head *rules, struct net_device *dev)
689 {
690 	struct fib_rule *rule;
691 
692 	list_for_each_entry(rule, rules, list) {
693 		if (rule->iifindex == dev->ifindex)
694 			rule->iifindex = -1;
695 		if (rule->oifindex == dev->ifindex)
696 			rule->oifindex = -1;
697 	}
698 }
699 
700 
701 static int fib_rules_event(struct notifier_block *this, unsigned long event,
702 			    void *ptr)
703 {
704 	struct net_device *dev = ptr;
705 	struct net *net = dev_net(dev);
706 	struct fib_rules_ops *ops;
707 
708 	ASSERT_RTNL();
709 
710 	switch (event) {
711 	case NETDEV_REGISTER:
712 		list_for_each_entry(ops, &net->rules_ops, list)
713 			attach_rules(&ops->rules_list, dev);
714 		break;
715 
716 	case NETDEV_UNREGISTER:
717 		list_for_each_entry(ops, &net->rules_ops, list)
718 			detach_rules(&ops->rules_list, dev);
719 		break;
720 	}
721 
722 	return NOTIFY_DONE;
723 }
724 
725 static struct notifier_block fib_rules_notifier = {
726 	.notifier_call = fib_rules_event,
727 };
728 
729 static int __net_init fib_rules_net_init(struct net *net)
730 {
731 	INIT_LIST_HEAD(&net->rules_ops);
732 	spin_lock_init(&net->rules_mod_lock);
733 	return 0;
734 }
735 
736 static struct pernet_operations fib_rules_net_ops = {
737 	.init = fib_rules_net_init,
738 };
739 
740 static int __init fib_rules_init(void)
741 {
742 	int err;
743 	rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
744 	rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
745 	rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
746 
747 	err = register_pernet_subsys(&fib_rules_net_ops);
748 	if (err < 0)
749 		goto fail;
750 
751 	err = register_netdevice_notifier(&fib_rules_notifier);
752 	if (err < 0)
753 		goto fail_unregister;
754 
755 	return 0;
756 
757 fail_unregister:
758 	unregister_pernet_subsys(&fib_rules_net_ops);
759 fail:
760 	rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
761 	rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
762 	rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
763 	return err;
764 }
765 
766 subsys_initcall(fib_rules_init);
767