xref: /openbmc/linux/net/core/fib_rules.c (revision 8b235f2f)
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 #include <net/ip_tunnels.h>
20 
21 int fib_default_rule_add(struct fib_rules_ops *ops,
22 			 u32 pref, u32 table, u32 flags)
23 {
24 	struct fib_rule *r;
25 
26 	r = kzalloc(ops->rule_size, GFP_KERNEL);
27 	if (r == NULL)
28 		return -ENOMEM;
29 
30 	atomic_set(&r->refcnt, 1);
31 	r->action = FR_ACT_TO_TBL;
32 	r->pref = pref;
33 	r->table = table;
34 	r->flags = flags;
35 	r->fr_net = ops->fro_net;
36 
37 	r->suppress_prefixlen = -1;
38 	r->suppress_ifgroup = -1;
39 
40 	/* The lock is not required here, the list in unreacheable
41 	 * at the moment this function is called */
42 	list_add_tail(&r->list, &ops->rules_list);
43 	return 0;
44 }
45 EXPORT_SYMBOL(fib_default_rule_add);
46 
47 u32 fib_default_rule_pref(struct fib_rules_ops *ops)
48 {
49 	struct list_head *pos;
50 	struct fib_rule *rule;
51 
52 	if (!list_empty(&ops->rules_list)) {
53 		pos = ops->rules_list.next;
54 		if (pos->next != &ops->rules_list) {
55 			rule = list_entry(pos->next, struct fib_rule, list);
56 			if (rule->pref)
57 				return rule->pref - 1;
58 		}
59 	}
60 
61 	return 0;
62 }
63 EXPORT_SYMBOL(fib_default_rule_pref);
64 
65 static void notify_rule_change(int event, struct fib_rule *rule,
66 			       struct fib_rules_ops *ops, struct nlmsghdr *nlh,
67 			       u32 pid);
68 
69 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
70 {
71 	struct fib_rules_ops *ops;
72 
73 	rcu_read_lock();
74 	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
75 		if (ops->family == family) {
76 			if (!try_module_get(ops->owner))
77 				ops = NULL;
78 			rcu_read_unlock();
79 			return ops;
80 		}
81 	}
82 	rcu_read_unlock();
83 
84 	return NULL;
85 }
86 
87 static void rules_ops_put(struct fib_rules_ops *ops)
88 {
89 	if (ops)
90 		module_put(ops->owner);
91 }
92 
93 static void flush_route_cache(struct fib_rules_ops *ops)
94 {
95 	if (ops->flush_cache)
96 		ops->flush_cache(ops);
97 }
98 
99 static int __fib_rules_register(struct fib_rules_ops *ops)
100 {
101 	int err = -EEXIST;
102 	struct fib_rules_ops *o;
103 	struct net *net;
104 
105 	net = ops->fro_net;
106 
107 	if (ops->rule_size < sizeof(struct fib_rule))
108 		return -EINVAL;
109 
110 	if (ops->match == NULL || ops->configure == NULL ||
111 	    ops->compare == NULL || ops->fill == NULL ||
112 	    ops->action == NULL)
113 		return -EINVAL;
114 
115 	spin_lock(&net->rules_mod_lock);
116 	list_for_each_entry(o, &net->rules_ops, list)
117 		if (ops->family == o->family)
118 			goto errout;
119 
120 	list_add_tail_rcu(&ops->list, &net->rules_ops);
121 	err = 0;
122 errout:
123 	spin_unlock(&net->rules_mod_lock);
124 
125 	return err;
126 }
127 
128 struct fib_rules_ops *
129 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
130 {
131 	struct fib_rules_ops *ops;
132 	int err;
133 
134 	ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
135 	if (ops == NULL)
136 		return ERR_PTR(-ENOMEM);
137 
138 	INIT_LIST_HEAD(&ops->rules_list);
139 	ops->fro_net = net;
140 
141 	err = __fib_rules_register(ops);
142 	if (err) {
143 		kfree(ops);
144 		ops = ERR_PTR(err);
145 	}
146 
147 	return ops;
148 }
149 EXPORT_SYMBOL_GPL(fib_rules_register);
150 
151 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
152 {
153 	struct fib_rule *rule, *tmp;
154 
155 	list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
156 		list_del_rcu(&rule->list);
157 		if (ops->delete)
158 			ops->delete(rule);
159 		fib_rule_put(rule);
160 	}
161 }
162 
163 void fib_rules_unregister(struct fib_rules_ops *ops)
164 {
165 	struct net *net = ops->fro_net;
166 
167 	spin_lock(&net->rules_mod_lock);
168 	list_del_rcu(&ops->list);
169 	spin_unlock(&net->rules_mod_lock);
170 
171 	fib_rules_cleanup_ops(ops);
172 	kfree_rcu(ops, rcu);
173 }
174 EXPORT_SYMBOL_GPL(fib_rules_unregister);
175 
176 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
177 			  struct flowi *fl, int flags)
178 {
179 	int ret = 0;
180 
181 	if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
182 		goto out;
183 
184 	if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
185 		goto out;
186 
187 	if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
188 		goto out;
189 
190 	if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
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 && ops->suppress && ops->suppress(rule, arg))
227 			continue;
228 
229 		if (err != -EAGAIN) {
230 			if ((arg->flags & FIB_LOOKUP_NOREF) ||
231 			    likely(atomic_inc_not_zero(&rule->refcnt))) {
232 				arg->rule = rule;
233 				goto out;
234 			}
235 			break;
236 		}
237 	}
238 
239 	err = -ESRCH;
240 out:
241 	rcu_read_unlock();
242 
243 	return err;
244 }
245 EXPORT_SYMBOL_GPL(fib_rules_lookup);
246 
247 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
248 			    struct fib_rules_ops *ops)
249 {
250 	int err = -EINVAL;
251 
252 	if (frh->src_len)
253 		if (tb[FRA_SRC] == NULL ||
254 		    frh->src_len > (ops->addr_size * 8) ||
255 		    nla_len(tb[FRA_SRC]) != ops->addr_size)
256 			goto errout;
257 
258 	if (frh->dst_len)
259 		if (tb[FRA_DST] == NULL ||
260 		    frh->dst_len > (ops->addr_size * 8) ||
261 		    nla_len(tb[FRA_DST]) != ops->addr_size)
262 			goto errout;
263 
264 	err = 0;
265 errout:
266 	return err;
267 }
268 
269 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
270 {
271 	struct net *net = sock_net(skb->sk);
272 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
273 	struct fib_rules_ops *ops = NULL;
274 	struct fib_rule *rule, *r, *last = NULL;
275 	struct nlattr *tb[FRA_MAX+1];
276 	int err = -EINVAL, unresolved = 0;
277 
278 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
279 		goto errout;
280 
281 	ops = lookup_rules_ops(net, frh->family);
282 	if (ops == NULL) {
283 		err = -EAFNOSUPPORT;
284 		goto errout;
285 	}
286 
287 	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
288 	if (err < 0)
289 		goto errout;
290 
291 	err = validate_rulemsg(frh, tb, ops);
292 	if (err < 0)
293 		goto errout;
294 
295 	rule = kzalloc(ops->rule_size, GFP_KERNEL);
296 	if (rule == NULL) {
297 		err = -ENOMEM;
298 		goto errout;
299 	}
300 	rule->fr_net = net;
301 
302 	if (tb[FRA_PRIORITY])
303 		rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
304 
305 	if (tb[FRA_IIFNAME]) {
306 		struct net_device *dev;
307 
308 		rule->iifindex = -1;
309 		nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
310 		dev = __dev_get_by_name(net, rule->iifname);
311 		if (dev)
312 			rule->iifindex = dev->ifindex;
313 	}
314 
315 	if (tb[FRA_OIFNAME]) {
316 		struct net_device *dev;
317 
318 		rule->oifindex = -1;
319 		nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
320 		dev = __dev_get_by_name(net, rule->oifname);
321 		if (dev)
322 			rule->oifindex = dev->ifindex;
323 	}
324 
325 	if (tb[FRA_FWMARK]) {
326 		rule->mark = nla_get_u32(tb[FRA_FWMARK]);
327 		if (rule->mark)
328 			/* compatibility: if the mark value is non-zero all bits
329 			 * are compared unless a mask is explicitly specified.
330 			 */
331 			rule->mark_mask = 0xFFFFFFFF;
332 	}
333 
334 	if (tb[FRA_FWMASK])
335 		rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
336 
337 	if (tb[FRA_TUN_ID])
338 		rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
339 
340 	rule->action = frh->action;
341 	rule->flags = frh->flags;
342 	rule->table = frh_get_table(frh, tb);
343 	if (tb[FRA_SUPPRESS_PREFIXLEN])
344 		rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
345 	else
346 		rule->suppress_prefixlen = -1;
347 
348 	if (tb[FRA_SUPPRESS_IFGROUP])
349 		rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
350 	else
351 		rule->suppress_ifgroup = -1;
352 
353 	if (!tb[FRA_PRIORITY] && ops->default_pref)
354 		rule->pref = ops->default_pref(ops);
355 
356 	err = -EINVAL;
357 	if (tb[FRA_GOTO]) {
358 		if (rule->action != FR_ACT_GOTO)
359 			goto errout_free;
360 
361 		rule->target = nla_get_u32(tb[FRA_GOTO]);
362 		/* Backward jumps are prohibited to avoid endless loops */
363 		if (rule->target <= rule->pref)
364 			goto errout_free;
365 
366 		list_for_each_entry(r, &ops->rules_list, list) {
367 			if (r->pref == rule->target) {
368 				RCU_INIT_POINTER(rule->ctarget, r);
369 				break;
370 			}
371 		}
372 
373 		if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
374 			unresolved = 1;
375 	} else if (rule->action == FR_ACT_GOTO)
376 		goto errout_free;
377 
378 	err = ops->configure(rule, skb, frh, tb);
379 	if (err < 0)
380 		goto errout_free;
381 
382 	list_for_each_entry(r, &ops->rules_list, list) {
383 		if (r->pref > rule->pref)
384 			break;
385 		last = r;
386 	}
387 
388 	fib_rule_get(rule);
389 
390 	if (last)
391 		list_add_rcu(&rule->list, &last->list);
392 	else
393 		list_add_rcu(&rule->list, &ops->rules_list);
394 
395 	if (ops->unresolved_rules) {
396 		/*
397 		 * There are unresolved goto rules in the list, check if
398 		 * any of them are pointing to this new rule.
399 		 */
400 		list_for_each_entry(r, &ops->rules_list, list) {
401 			if (r->action == FR_ACT_GOTO &&
402 			    r->target == rule->pref &&
403 			    rtnl_dereference(r->ctarget) == NULL) {
404 				rcu_assign_pointer(r->ctarget, rule);
405 				if (--ops->unresolved_rules == 0)
406 					break;
407 			}
408 		}
409 	}
410 
411 	if (rule->action == FR_ACT_GOTO)
412 		ops->nr_goto_rules++;
413 
414 	if (unresolved)
415 		ops->unresolved_rules++;
416 
417 	if (rule->tun_id)
418 		ip_tunnel_need_metadata();
419 
420 	notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
421 	flush_route_cache(ops);
422 	rules_ops_put(ops);
423 	return 0;
424 
425 errout_free:
426 	kfree(rule);
427 errout:
428 	rules_ops_put(ops);
429 	return err;
430 }
431 
432 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
433 {
434 	struct net *net = sock_net(skb->sk);
435 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
436 	struct fib_rules_ops *ops = NULL;
437 	struct fib_rule *rule, *tmp;
438 	struct nlattr *tb[FRA_MAX+1];
439 	int err = -EINVAL;
440 
441 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
442 		goto errout;
443 
444 	ops = lookup_rules_ops(net, frh->family);
445 	if (ops == NULL) {
446 		err = -EAFNOSUPPORT;
447 		goto errout;
448 	}
449 
450 	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
451 	if (err < 0)
452 		goto errout;
453 
454 	err = validate_rulemsg(frh, tb, ops);
455 	if (err < 0)
456 		goto errout;
457 
458 	list_for_each_entry(rule, &ops->rules_list, list) {
459 		if (frh->action && (frh->action != rule->action))
460 			continue;
461 
462 		if (frh_get_table(frh, tb) &&
463 		    (frh_get_table(frh, tb) != rule->table))
464 			continue;
465 
466 		if (tb[FRA_PRIORITY] &&
467 		    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
468 			continue;
469 
470 		if (tb[FRA_IIFNAME] &&
471 		    nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
472 			continue;
473 
474 		if (tb[FRA_OIFNAME] &&
475 		    nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
476 			continue;
477 
478 		if (tb[FRA_FWMARK] &&
479 		    (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
480 			continue;
481 
482 		if (tb[FRA_FWMASK] &&
483 		    (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
484 			continue;
485 
486 		if (tb[FRA_TUN_ID] &&
487 		    (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
488 			continue;
489 
490 		if (!ops->compare(rule, frh, tb))
491 			continue;
492 
493 		if (rule->flags & FIB_RULE_PERMANENT) {
494 			err = -EPERM;
495 			goto errout;
496 		}
497 
498 		if (ops->delete) {
499 			err = ops->delete(rule);
500 			if (err)
501 				goto errout;
502 		}
503 
504 		if (rule->tun_id)
505 			ip_tunnel_unneed_metadata();
506 
507 		list_del_rcu(&rule->list);
508 
509 		if (rule->action == FR_ACT_GOTO) {
510 			ops->nr_goto_rules--;
511 			if (rtnl_dereference(rule->ctarget) == NULL)
512 				ops->unresolved_rules--;
513 		}
514 
515 		/*
516 		 * Check if this rule is a target to any of them. If so,
517 		 * disable them. As this operation is eventually very
518 		 * expensive, it is only performed if goto rules have
519 		 * actually been added.
520 		 */
521 		if (ops->nr_goto_rules > 0) {
522 			list_for_each_entry(tmp, &ops->rules_list, list) {
523 				if (rtnl_dereference(tmp->ctarget) == rule) {
524 					RCU_INIT_POINTER(tmp->ctarget, NULL);
525 					ops->unresolved_rules++;
526 				}
527 			}
528 		}
529 
530 		notify_rule_change(RTM_DELRULE, rule, ops, nlh,
531 				   NETLINK_CB(skb).portid);
532 		fib_rule_put(rule);
533 		flush_route_cache(ops);
534 		rules_ops_put(ops);
535 		return 0;
536 	}
537 
538 	err = -ENOENT;
539 errout:
540 	rules_ops_put(ops);
541 	return err;
542 }
543 
544 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
545 					 struct fib_rule *rule)
546 {
547 	size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
548 			 + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
549 			 + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
550 			 + nla_total_size(4) /* FRA_PRIORITY */
551 			 + nla_total_size(4) /* FRA_TABLE */
552 			 + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
553 			 + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
554 			 + nla_total_size(4) /* FRA_FWMARK */
555 			 + nla_total_size(4) /* FRA_FWMASK */
556 			 + nla_total_size(8); /* FRA_TUN_ID */
557 
558 	if (ops->nlmsg_payload)
559 		payload += ops->nlmsg_payload(rule);
560 
561 	return payload;
562 }
563 
564 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
565 			    u32 pid, u32 seq, int type, int flags,
566 			    struct fib_rules_ops *ops)
567 {
568 	struct nlmsghdr *nlh;
569 	struct fib_rule_hdr *frh;
570 
571 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
572 	if (nlh == NULL)
573 		return -EMSGSIZE;
574 
575 	frh = nlmsg_data(nlh);
576 	frh->family = ops->family;
577 	frh->table = rule->table;
578 	if (nla_put_u32(skb, FRA_TABLE, rule->table))
579 		goto nla_put_failure;
580 	if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
581 		goto nla_put_failure;
582 	frh->res1 = 0;
583 	frh->res2 = 0;
584 	frh->action = rule->action;
585 	frh->flags = rule->flags;
586 
587 	if (rule->action == FR_ACT_GOTO &&
588 	    rcu_access_pointer(rule->ctarget) == NULL)
589 		frh->flags |= FIB_RULE_UNRESOLVED;
590 
591 	if (rule->iifname[0]) {
592 		if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
593 			goto nla_put_failure;
594 		if (rule->iifindex == -1)
595 			frh->flags |= FIB_RULE_IIF_DETACHED;
596 	}
597 
598 	if (rule->oifname[0]) {
599 		if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
600 			goto nla_put_failure;
601 		if (rule->oifindex == -1)
602 			frh->flags |= FIB_RULE_OIF_DETACHED;
603 	}
604 
605 	if ((rule->pref &&
606 	     nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
607 	    (rule->mark &&
608 	     nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
609 	    ((rule->mark_mask || rule->mark) &&
610 	     nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
611 	    (rule->target &&
612 	     nla_put_u32(skb, FRA_GOTO, rule->target)) ||
613 	    (rule->tun_id &&
614 	     nla_put_be64(skb, FRA_TUN_ID, rule->tun_id)))
615 		goto nla_put_failure;
616 
617 	if (rule->suppress_ifgroup != -1) {
618 		if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
619 			goto nla_put_failure;
620 	}
621 
622 	if (ops->fill(rule, skb, frh) < 0)
623 		goto nla_put_failure;
624 
625 	nlmsg_end(skb, nlh);
626 	return 0;
627 
628 nla_put_failure:
629 	nlmsg_cancel(skb, nlh);
630 	return -EMSGSIZE;
631 }
632 
633 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
634 		      struct fib_rules_ops *ops)
635 {
636 	int idx = 0;
637 	struct fib_rule *rule;
638 
639 	rcu_read_lock();
640 	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
641 		if (idx < cb->args[1])
642 			goto skip;
643 
644 		if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
645 				     cb->nlh->nlmsg_seq, RTM_NEWRULE,
646 				     NLM_F_MULTI, ops) < 0)
647 			break;
648 skip:
649 		idx++;
650 	}
651 	rcu_read_unlock();
652 	cb->args[1] = idx;
653 	rules_ops_put(ops);
654 
655 	return skb->len;
656 }
657 
658 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
659 {
660 	struct net *net = sock_net(skb->sk);
661 	struct fib_rules_ops *ops;
662 	int idx = 0, family;
663 
664 	family = rtnl_msg_family(cb->nlh);
665 	if (family != AF_UNSPEC) {
666 		/* Protocol specific dump request */
667 		ops = lookup_rules_ops(net, family);
668 		if (ops == NULL)
669 			return -EAFNOSUPPORT;
670 
671 		return dump_rules(skb, cb, ops);
672 	}
673 
674 	rcu_read_lock();
675 	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
676 		if (idx < cb->args[0] || !try_module_get(ops->owner))
677 			goto skip;
678 
679 		if (dump_rules(skb, cb, ops) < 0)
680 			break;
681 
682 		cb->args[1] = 0;
683 skip:
684 		idx++;
685 	}
686 	rcu_read_unlock();
687 	cb->args[0] = idx;
688 
689 	return skb->len;
690 }
691 
692 static void notify_rule_change(int event, struct fib_rule *rule,
693 			       struct fib_rules_ops *ops, struct nlmsghdr *nlh,
694 			       u32 pid)
695 {
696 	struct net *net;
697 	struct sk_buff *skb;
698 	int err = -ENOBUFS;
699 
700 	net = ops->fro_net;
701 	skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
702 	if (skb == NULL)
703 		goto errout;
704 
705 	err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
706 	if (err < 0) {
707 		/* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
708 		WARN_ON(err == -EMSGSIZE);
709 		kfree_skb(skb);
710 		goto errout;
711 	}
712 
713 	rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
714 	return;
715 errout:
716 	if (err < 0)
717 		rtnl_set_sk_err(net, ops->nlgroup, err);
718 }
719 
720 static void attach_rules(struct list_head *rules, struct net_device *dev)
721 {
722 	struct fib_rule *rule;
723 
724 	list_for_each_entry(rule, rules, list) {
725 		if (rule->iifindex == -1 &&
726 		    strcmp(dev->name, rule->iifname) == 0)
727 			rule->iifindex = dev->ifindex;
728 		if (rule->oifindex == -1 &&
729 		    strcmp(dev->name, rule->oifname) == 0)
730 			rule->oifindex = dev->ifindex;
731 	}
732 }
733 
734 static void detach_rules(struct list_head *rules, struct net_device *dev)
735 {
736 	struct fib_rule *rule;
737 
738 	list_for_each_entry(rule, rules, list) {
739 		if (rule->iifindex == dev->ifindex)
740 			rule->iifindex = -1;
741 		if (rule->oifindex == dev->ifindex)
742 			rule->oifindex = -1;
743 	}
744 }
745 
746 
747 static int fib_rules_event(struct notifier_block *this, unsigned long event,
748 			   void *ptr)
749 {
750 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
751 	struct net *net = dev_net(dev);
752 	struct fib_rules_ops *ops;
753 
754 	ASSERT_RTNL();
755 
756 	switch (event) {
757 	case NETDEV_REGISTER:
758 		list_for_each_entry(ops, &net->rules_ops, list)
759 			attach_rules(&ops->rules_list, dev);
760 		break;
761 
762 	case NETDEV_CHANGENAME:
763 		list_for_each_entry(ops, &net->rules_ops, list) {
764 			detach_rules(&ops->rules_list, dev);
765 			attach_rules(&ops->rules_list, dev);
766 		}
767 		break;
768 
769 	case NETDEV_UNREGISTER:
770 		list_for_each_entry(ops, &net->rules_ops, list)
771 			detach_rules(&ops->rules_list, dev);
772 		break;
773 	}
774 
775 	return NOTIFY_DONE;
776 }
777 
778 static struct notifier_block fib_rules_notifier = {
779 	.notifier_call = fib_rules_event,
780 };
781 
782 static int __net_init fib_rules_net_init(struct net *net)
783 {
784 	INIT_LIST_HEAD(&net->rules_ops);
785 	spin_lock_init(&net->rules_mod_lock);
786 	return 0;
787 }
788 
789 static struct pernet_operations fib_rules_net_ops = {
790 	.init = fib_rules_net_init,
791 };
792 
793 static int __init fib_rules_init(void)
794 {
795 	int err;
796 	rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
797 	rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
798 	rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
799 
800 	err = register_pernet_subsys(&fib_rules_net_ops);
801 	if (err < 0)
802 		goto fail;
803 
804 	err = register_netdevice_notifier(&fib_rules_notifier);
805 	if (err < 0)
806 		goto fail_unregister;
807 
808 	return 0;
809 
810 fail_unregister:
811 	unregister_pernet_subsys(&fib_rules_net_ops);
812 fail:
813 	rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
814 	rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
815 	rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
816 	return err;
817 }
818 
819 subsys_initcall(fib_rules_init);
820