xref: /openbmc/linux/net/core/fib_rules.c (revision 9cfc5c90)
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 static 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 
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 	if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
190 		goto out;
191 
192 	ret = ops->match(rule, fl, flags);
193 out:
194 	return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
195 }
196 
197 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
198 		     int flags, struct fib_lookup_arg *arg)
199 {
200 	struct fib_rule *rule;
201 	int err;
202 
203 	rcu_read_lock();
204 
205 	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
206 jumped:
207 		if (!fib_rule_match(rule, ops, fl, flags))
208 			continue;
209 
210 		if (rule->action == FR_ACT_GOTO) {
211 			struct fib_rule *target;
212 
213 			target = rcu_dereference(rule->ctarget);
214 			if (target == NULL) {
215 				continue;
216 			} else {
217 				rule = target;
218 				goto jumped;
219 			}
220 		} else if (rule->action == FR_ACT_NOP)
221 			continue;
222 		else
223 			err = ops->action(rule, fl, flags, arg);
224 
225 		if (!err && ops->suppress && ops->suppress(rule, arg))
226 			continue;
227 
228 		if (err != -EAGAIN) {
229 			if ((arg->flags & FIB_LOOKUP_NOREF) ||
230 			    likely(atomic_inc_not_zero(&rule->refcnt))) {
231 				arg->rule = rule;
232 				goto out;
233 			}
234 			break;
235 		}
236 	}
237 
238 	err = -ESRCH;
239 out:
240 	rcu_read_unlock();
241 
242 	return err;
243 }
244 EXPORT_SYMBOL_GPL(fib_rules_lookup);
245 
246 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
247 			    struct fib_rules_ops *ops)
248 {
249 	int err = -EINVAL;
250 
251 	if (frh->src_len)
252 		if (tb[FRA_SRC] == NULL ||
253 		    frh->src_len > (ops->addr_size * 8) ||
254 		    nla_len(tb[FRA_SRC]) != ops->addr_size)
255 			goto errout;
256 
257 	if (frh->dst_len)
258 		if (tb[FRA_DST] == NULL ||
259 		    frh->dst_len > (ops->addr_size * 8) ||
260 		    nla_len(tb[FRA_DST]) != ops->addr_size)
261 			goto errout;
262 
263 	err = 0;
264 errout:
265 	return err;
266 }
267 
268 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
269 {
270 	struct net *net = sock_net(skb->sk);
271 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
272 	struct fib_rules_ops *ops = NULL;
273 	struct fib_rule *rule, *r, *last = NULL;
274 	struct nlattr *tb[FRA_MAX+1];
275 	int err = -EINVAL, unresolved = 0;
276 
277 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
278 		goto errout;
279 
280 	ops = lookup_rules_ops(net, frh->family);
281 	if (ops == NULL) {
282 		err = -EAFNOSUPPORT;
283 		goto errout;
284 	}
285 
286 	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
287 	if (err < 0)
288 		goto errout;
289 
290 	err = validate_rulemsg(frh, tb, ops);
291 	if (err < 0)
292 		goto errout;
293 
294 	rule = kzalloc(ops->rule_size, GFP_KERNEL);
295 	if (rule == NULL) {
296 		err = -ENOMEM;
297 		goto errout;
298 	}
299 	rule->fr_net = net;
300 
301 	rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
302 	                              : fib_default_rule_pref(ops);
303 
304 	if (tb[FRA_IIFNAME]) {
305 		struct net_device *dev;
306 
307 		rule->iifindex = -1;
308 		nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
309 		dev = __dev_get_by_name(net, rule->iifname);
310 		if (dev)
311 			rule->iifindex = dev->ifindex;
312 	}
313 
314 	if (tb[FRA_OIFNAME]) {
315 		struct net_device *dev;
316 
317 		rule->oifindex = -1;
318 		nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
319 		dev = __dev_get_by_name(net, rule->oifname);
320 		if (dev)
321 			rule->oifindex = dev->ifindex;
322 	}
323 
324 	if (tb[FRA_FWMARK]) {
325 		rule->mark = nla_get_u32(tb[FRA_FWMARK]);
326 		if (rule->mark)
327 			/* compatibility: if the mark value is non-zero all bits
328 			 * are compared unless a mask is explicitly specified.
329 			 */
330 			rule->mark_mask = 0xFFFFFFFF;
331 	}
332 
333 	if (tb[FRA_FWMASK])
334 		rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
335 
336 	if (tb[FRA_TUN_ID])
337 		rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
338 
339 	rule->action = frh->action;
340 	rule->flags = frh->flags;
341 	rule->table = frh_get_table(frh, tb);
342 	if (tb[FRA_SUPPRESS_PREFIXLEN])
343 		rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
344 	else
345 		rule->suppress_prefixlen = -1;
346 
347 	if (tb[FRA_SUPPRESS_IFGROUP])
348 		rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
349 	else
350 		rule->suppress_ifgroup = -1;
351 
352 	err = -EINVAL;
353 	if (tb[FRA_GOTO]) {
354 		if (rule->action != FR_ACT_GOTO)
355 			goto errout_free;
356 
357 		rule->target = nla_get_u32(tb[FRA_GOTO]);
358 		/* Backward jumps are prohibited to avoid endless loops */
359 		if (rule->target <= rule->pref)
360 			goto errout_free;
361 
362 		list_for_each_entry(r, &ops->rules_list, list) {
363 			if (r->pref == rule->target) {
364 				RCU_INIT_POINTER(rule->ctarget, r);
365 				break;
366 			}
367 		}
368 
369 		if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
370 			unresolved = 1;
371 	} else if (rule->action == FR_ACT_GOTO)
372 		goto errout_free;
373 
374 	err = ops->configure(rule, skb, frh, tb);
375 	if (err < 0)
376 		goto errout_free;
377 
378 	list_for_each_entry(r, &ops->rules_list, list) {
379 		if (r->pref > rule->pref)
380 			break;
381 		last = r;
382 	}
383 
384 	fib_rule_get(rule);
385 
386 	if (last)
387 		list_add_rcu(&rule->list, &last->list);
388 	else
389 		list_add_rcu(&rule->list, &ops->rules_list);
390 
391 	if (ops->unresolved_rules) {
392 		/*
393 		 * There are unresolved goto rules in the list, check if
394 		 * any of them are pointing to this new rule.
395 		 */
396 		list_for_each_entry(r, &ops->rules_list, list) {
397 			if (r->action == FR_ACT_GOTO &&
398 			    r->target == rule->pref &&
399 			    rtnl_dereference(r->ctarget) == NULL) {
400 				rcu_assign_pointer(r->ctarget, rule);
401 				if (--ops->unresolved_rules == 0)
402 					break;
403 			}
404 		}
405 	}
406 
407 	if (rule->action == FR_ACT_GOTO)
408 		ops->nr_goto_rules++;
409 
410 	if (unresolved)
411 		ops->unresolved_rules++;
412 
413 	if (rule->tun_id)
414 		ip_tunnel_need_metadata();
415 
416 	notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
417 	flush_route_cache(ops);
418 	rules_ops_put(ops);
419 	return 0;
420 
421 errout_free:
422 	kfree(rule);
423 errout:
424 	rules_ops_put(ops);
425 	return err;
426 }
427 
428 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
429 {
430 	struct net *net = sock_net(skb->sk);
431 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
432 	struct fib_rules_ops *ops = NULL;
433 	struct fib_rule *rule, *tmp;
434 	struct nlattr *tb[FRA_MAX+1];
435 	int err = -EINVAL;
436 
437 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
438 		goto errout;
439 
440 	ops = lookup_rules_ops(net, frh->family);
441 	if (ops == NULL) {
442 		err = -EAFNOSUPPORT;
443 		goto errout;
444 	}
445 
446 	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
447 	if (err < 0)
448 		goto errout;
449 
450 	err = validate_rulemsg(frh, tb, ops);
451 	if (err < 0)
452 		goto errout;
453 
454 	list_for_each_entry(rule, &ops->rules_list, list) {
455 		if (frh->action && (frh->action != rule->action))
456 			continue;
457 
458 		if (frh_get_table(frh, tb) &&
459 		    (frh_get_table(frh, tb) != rule->table))
460 			continue;
461 
462 		if (tb[FRA_PRIORITY] &&
463 		    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
464 			continue;
465 
466 		if (tb[FRA_IIFNAME] &&
467 		    nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
468 			continue;
469 
470 		if (tb[FRA_OIFNAME] &&
471 		    nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
472 			continue;
473 
474 		if (tb[FRA_FWMARK] &&
475 		    (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
476 			continue;
477 
478 		if (tb[FRA_FWMASK] &&
479 		    (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
480 			continue;
481 
482 		if (tb[FRA_TUN_ID] &&
483 		    (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
484 			continue;
485 
486 		if (!ops->compare(rule, frh, tb))
487 			continue;
488 
489 		if (rule->flags & FIB_RULE_PERMANENT) {
490 			err = -EPERM;
491 			goto errout;
492 		}
493 
494 		if (ops->delete) {
495 			err = ops->delete(rule);
496 			if (err)
497 				goto errout;
498 		}
499 
500 		if (rule->tun_id)
501 			ip_tunnel_unneed_metadata();
502 
503 		list_del_rcu(&rule->list);
504 
505 		if (rule->action == FR_ACT_GOTO) {
506 			ops->nr_goto_rules--;
507 			if (rtnl_dereference(rule->ctarget) == NULL)
508 				ops->unresolved_rules--;
509 		}
510 
511 		/*
512 		 * Check if this rule is a target to any of them. If so,
513 		 * disable them. As this operation is eventually very
514 		 * expensive, it is only performed if goto rules have
515 		 * actually been added.
516 		 */
517 		if (ops->nr_goto_rules > 0) {
518 			list_for_each_entry(tmp, &ops->rules_list, list) {
519 				if (rtnl_dereference(tmp->ctarget) == rule) {
520 					RCU_INIT_POINTER(tmp->ctarget, NULL);
521 					ops->unresolved_rules++;
522 				}
523 			}
524 		}
525 
526 		notify_rule_change(RTM_DELRULE, rule, ops, nlh,
527 				   NETLINK_CB(skb).portid);
528 		fib_rule_put(rule);
529 		flush_route_cache(ops);
530 		rules_ops_put(ops);
531 		return 0;
532 	}
533 
534 	err = -ENOENT;
535 errout:
536 	rules_ops_put(ops);
537 	return err;
538 }
539 
540 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
541 					 struct fib_rule *rule)
542 {
543 	size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
544 			 + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
545 			 + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
546 			 + nla_total_size(4) /* FRA_PRIORITY */
547 			 + nla_total_size(4) /* FRA_TABLE */
548 			 + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
549 			 + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
550 			 + nla_total_size(4) /* FRA_FWMARK */
551 			 + nla_total_size(4) /* FRA_FWMASK */
552 			 + nla_total_size(8); /* FRA_TUN_ID */
553 
554 	if (ops->nlmsg_payload)
555 		payload += ops->nlmsg_payload(rule);
556 
557 	return payload;
558 }
559 
560 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
561 			    u32 pid, u32 seq, int type, int flags,
562 			    struct fib_rules_ops *ops)
563 {
564 	struct nlmsghdr *nlh;
565 	struct fib_rule_hdr *frh;
566 
567 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
568 	if (nlh == NULL)
569 		return -EMSGSIZE;
570 
571 	frh = nlmsg_data(nlh);
572 	frh->family = ops->family;
573 	frh->table = rule->table;
574 	if (nla_put_u32(skb, FRA_TABLE, rule->table))
575 		goto nla_put_failure;
576 	if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
577 		goto nla_put_failure;
578 	frh->res1 = 0;
579 	frh->res2 = 0;
580 	frh->action = rule->action;
581 	frh->flags = rule->flags;
582 
583 	if (rule->action == FR_ACT_GOTO &&
584 	    rcu_access_pointer(rule->ctarget) == NULL)
585 		frh->flags |= FIB_RULE_UNRESOLVED;
586 
587 	if (rule->iifname[0]) {
588 		if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
589 			goto nla_put_failure;
590 		if (rule->iifindex == -1)
591 			frh->flags |= FIB_RULE_IIF_DETACHED;
592 	}
593 
594 	if (rule->oifname[0]) {
595 		if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
596 			goto nla_put_failure;
597 		if (rule->oifindex == -1)
598 			frh->flags |= FIB_RULE_OIF_DETACHED;
599 	}
600 
601 	if ((rule->pref &&
602 	     nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
603 	    (rule->mark &&
604 	     nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
605 	    ((rule->mark_mask || rule->mark) &&
606 	     nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
607 	    (rule->target &&
608 	     nla_put_u32(skb, FRA_GOTO, rule->target)) ||
609 	    (rule->tun_id &&
610 	     nla_put_be64(skb, FRA_TUN_ID, rule->tun_id)))
611 		goto nla_put_failure;
612 
613 	if (rule->suppress_ifgroup != -1) {
614 		if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
615 			goto nla_put_failure;
616 	}
617 
618 	if (ops->fill(rule, skb, frh) < 0)
619 		goto nla_put_failure;
620 
621 	nlmsg_end(skb, nlh);
622 	return 0;
623 
624 nla_put_failure:
625 	nlmsg_cancel(skb, nlh);
626 	return -EMSGSIZE;
627 }
628 
629 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
630 		      struct fib_rules_ops *ops)
631 {
632 	int idx = 0;
633 	struct fib_rule *rule;
634 	int err = 0;
635 
636 	rcu_read_lock();
637 	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
638 		if (idx < cb->args[1])
639 			goto skip;
640 
641 		err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
642 				       cb->nlh->nlmsg_seq, RTM_NEWRULE,
643 				       NLM_F_MULTI, ops);
644 		if (err)
645 			break;
646 skip:
647 		idx++;
648 	}
649 	rcu_read_unlock();
650 	cb->args[1] = idx;
651 	rules_ops_put(ops);
652 
653 	return err;
654 }
655 
656 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
657 {
658 	struct net *net = sock_net(skb->sk);
659 	struct fib_rules_ops *ops;
660 	int idx = 0, family;
661 
662 	family = rtnl_msg_family(cb->nlh);
663 	if (family != AF_UNSPEC) {
664 		/* Protocol specific dump request */
665 		ops = lookup_rules_ops(net, family);
666 		if (ops == NULL)
667 			return -EAFNOSUPPORT;
668 
669 		dump_rules(skb, cb, ops);
670 
671 		return skb->len;
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