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Linux/net/core/fib_rules.c

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  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 = hold_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         hold_net(net);
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 static void fib_rules_put_rcu(struct rcu_head *head)
164 {
165         struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
166         struct net *net = ops->fro_net;
167 
168         release_net(net);
169         kfree(ops);
170 }
171 
172 void fib_rules_unregister(struct fib_rules_ops *ops)
173 {
174         struct net *net = ops->fro_net;
175 
176         spin_lock(&net->rules_mod_lock);
177         list_del_rcu(&ops->list);
178         fib_rules_cleanup_ops(ops);
179         spin_unlock(&net->rules_mod_lock);
180 
181         call_rcu(&ops->rcu, fib_rules_put_rcu);
182 }
183 EXPORT_SYMBOL_GPL(fib_rules_unregister);
184 
185 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
186                           struct flowi *fl, int flags)
187 {
188         int ret = 0;
189 
190         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
191                 goto out;
192 
193         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
194                 goto out;
195 
196         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
197                 goto out;
198 
199         ret = ops->match(rule, fl, flags);
200 out:
201         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
202 }
203 
204 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
205                      int flags, struct fib_lookup_arg *arg)
206 {
207         struct fib_rule *rule;
208         int err;
209 
210         rcu_read_lock();
211 
212         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
213 jumped:
214                 if (!fib_rule_match(rule, ops, fl, flags))
215                         continue;
216 
217                 if (rule->action == FR_ACT_GOTO) {
218                         struct fib_rule *target;
219 
220                         target = rcu_dereference(rule->ctarget);
221                         if (target == NULL) {
222                                 continue;
223                         } else {
224                                 rule = target;
225                                 goto jumped;
226                         }
227                 } else if (rule->action == FR_ACT_NOP)
228                         continue;
229                 else
230                         err = ops->action(rule, fl, flags, arg);
231 
232                 if (!err && ops->suppress && ops->suppress(rule, arg))
233                         continue;
234 
235                 if (err != -EAGAIN) {
236                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
237                             likely(atomic_inc_not_zero(&rule->refcnt))) {
238                                 arg->rule = rule;
239                                 goto out;
240                         }
241                         break;
242                 }
243         }
244 
245         err = -ESRCH;
246 out:
247         rcu_read_unlock();
248 
249         return err;
250 }
251 EXPORT_SYMBOL_GPL(fib_rules_lookup);
252 
253 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
254                             struct fib_rules_ops *ops)
255 {
256         int err = -EINVAL;
257 
258         if (frh->src_len)
259                 if (tb[FRA_SRC] == NULL ||
260                     frh->src_len > (ops->addr_size * 8) ||
261                     nla_len(tb[FRA_SRC]) != ops->addr_size)
262                         goto errout;
263 
264         if (frh->dst_len)
265                 if (tb[FRA_DST] == NULL ||
266                     frh->dst_len > (ops->addr_size * 8) ||
267                     nla_len(tb[FRA_DST]) != ops->addr_size)
268                         goto errout;
269 
270         err = 0;
271 errout:
272         return err;
273 }
274 
275 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
276 {
277         struct net *net = sock_net(skb->sk);
278         struct fib_rule_hdr *frh = nlmsg_data(nlh);
279         struct fib_rules_ops *ops = NULL;
280         struct fib_rule *rule, *r, *last = NULL;
281         struct nlattr *tb[FRA_MAX+1];
282         int err = -EINVAL, unresolved = 0;
283 
284         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
285                 goto errout;
286 
287         ops = lookup_rules_ops(net, frh->family);
288         if (ops == NULL) {
289                 err = -EAFNOSUPPORT;
290                 goto errout;
291         }
292 
293         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
294         if (err < 0)
295                 goto errout;
296 
297         err = validate_rulemsg(frh, tb, ops);
298         if (err < 0)
299                 goto errout;
300 
301         rule = kzalloc(ops->rule_size, GFP_KERNEL);
302         if (rule == NULL) {
303                 err = -ENOMEM;
304                 goto errout;
305         }
306         rule->fr_net = hold_net(net);
307 
308         if (tb[FRA_PRIORITY])
309                 rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
310 
311         if (tb[FRA_IIFNAME]) {
312                 struct net_device *dev;
313 
314                 rule->iifindex = -1;
315                 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
316                 dev = __dev_get_by_name(net, rule->iifname);
317                 if (dev)
318                         rule->iifindex = dev->ifindex;
319         }
320 
321         if (tb[FRA_OIFNAME]) {
322                 struct net_device *dev;
323 
324                 rule->oifindex = -1;
325                 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
326                 dev = __dev_get_by_name(net, rule->oifname);
327                 if (dev)
328                         rule->oifindex = dev->ifindex;
329         }
330 
331         if (tb[FRA_FWMARK]) {
332                 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
333                 if (rule->mark)
334                         /* compatibility: if the mark value is non-zero all bits
335                          * are compared unless a mask is explicitly specified.
336                          */
337                         rule->mark_mask = 0xFFFFFFFF;
338         }
339 
340         if (tb[FRA_FWMASK])
341                 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
342 
343         rule->action = frh->action;
344         rule->flags = frh->flags;
345         rule->table = frh_get_table(frh, tb);
346         if (tb[FRA_SUPPRESS_PREFIXLEN])
347                 rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
348         else
349                 rule->suppress_prefixlen = -1;
350 
351         if (tb[FRA_SUPPRESS_IFGROUP])
352                 rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
353         else
354                 rule->suppress_ifgroup = -1;
355 
356         if (!tb[FRA_PRIORITY] && ops->default_pref)
357                 rule->pref = ops->default_pref(ops);
358 
359         err = -EINVAL;
360         if (tb[FRA_GOTO]) {
361                 if (rule->action != FR_ACT_GOTO)
362                         goto errout_free;
363 
364                 rule->target = nla_get_u32(tb[FRA_GOTO]);
365                 /* Backward jumps are prohibited to avoid endless loops */
366                 if (rule->target <= rule->pref)
367                         goto errout_free;
368 
369                 list_for_each_entry(r, &ops->rules_list, list) {
370                         if (r->pref == rule->target) {
371                                 RCU_INIT_POINTER(rule->ctarget, r);
372                                 break;
373                         }
374                 }
375 
376                 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
377                         unresolved = 1;
378         } else if (rule->action == FR_ACT_GOTO)
379                 goto errout_free;
380 
381         err = ops->configure(rule, skb, frh, tb);
382         if (err < 0)
383                 goto errout_free;
384 
385         list_for_each_entry(r, &ops->rules_list, list) {
386                 if (r->pref > rule->pref)
387                         break;
388                 last = r;
389         }
390 
391         fib_rule_get(rule);
392 
393         if (last)
394                 list_add_rcu(&rule->list, &last->list);
395         else
396                 list_add_rcu(&rule->list, &ops->rules_list);
397 
398         if (ops->unresolved_rules) {
399                 /*
400                  * There are unresolved goto rules in the list, check if
401                  * any of them are pointing to this new rule.
402                  */
403                 list_for_each_entry(r, &ops->rules_list, list) {
404                         if (r->action == FR_ACT_GOTO &&
405                             r->target == rule->pref &&
406                             rtnl_dereference(r->ctarget) == NULL) {
407                                 rcu_assign_pointer(r->ctarget, rule);
408                                 if (--ops->unresolved_rules == 0)
409                                         break;
410                         }
411                 }
412         }
413 
414         if (rule->action == FR_ACT_GOTO)
415                 ops->nr_goto_rules++;
416 
417         if (unresolved)
418                 ops->unresolved_rules++;
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         release_net(rule->fr_net);
427         kfree(rule);
428 errout:
429         rules_ops_put(ops);
430         return err;
431 }
432 
433 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
434 {
435         struct net *net = sock_net(skb->sk);
436         struct fib_rule_hdr *frh = nlmsg_data(nlh);
437         struct fib_rules_ops *ops = NULL;
438         struct fib_rule *rule, *tmp;
439         struct nlattr *tb[FRA_MAX+1];
440         int err = -EINVAL;
441 
442         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
443                 goto errout;
444 
445         ops = lookup_rules_ops(net, frh->family);
446         if (ops == NULL) {
447                 err = -EAFNOSUPPORT;
448                 goto errout;
449         }
450 
451         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
452         if (err < 0)
453                 goto errout;
454 
455         err = validate_rulemsg(frh, tb, ops);
456         if (err < 0)
457                 goto errout;
458 
459         list_for_each_entry(rule, &ops->rules_list, list) {
460                 if (frh->action && (frh->action != rule->action))
461                         continue;
462 
463                 if (frh_get_table(frh, tb) &&
464                     (frh_get_table(frh, tb) != rule->table))
465                         continue;
466 
467                 if (tb[FRA_PRIORITY] &&
468                     (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
469                         continue;
470 
471                 if (tb[FRA_IIFNAME] &&
472                     nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
473                         continue;
474 
475                 if (tb[FRA_OIFNAME] &&
476                     nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
477                         continue;
478 
479                 if (tb[FRA_FWMARK] &&
480                     (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
481                         continue;
482 
483                 if (tb[FRA_FWMASK] &&
484                     (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
485                         continue;
486 
487                 if (!ops->compare(rule, frh, tb))
488                         continue;
489 
490                 if (rule->flags & FIB_RULE_PERMANENT) {
491                         err = -EPERM;
492                         goto errout;
493                 }
494 
495                 list_del_rcu(&rule->list);
496 
497                 if (rule->action == FR_ACT_GOTO) {
498                         ops->nr_goto_rules--;
499                         if (rtnl_dereference(rule->ctarget) == NULL)
500                                 ops->unresolved_rules--;
501                 }
502 
503                 /*
504                  * Check if this rule is a target to any of them. If so,
505                  * disable them. As this operation is eventually very
506                  * expensive, it is only performed if goto rules have
507                  * actually been added.
508                  */
509                 if (ops->nr_goto_rules > 0) {
510                         list_for_each_entry(tmp, &ops->rules_list, list) {
511                                 if (rtnl_dereference(tmp->ctarget) == rule) {
512                                         RCU_INIT_POINTER(tmp->ctarget, NULL);
513                                         ops->unresolved_rules++;
514                                 }
515                         }
516                 }
517 
518                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
519                                    NETLINK_CB(skb).portid);
520                 if (ops->delete)
521                         ops->delete(rule);
522                 fib_rule_put(rule);
523                 flush_route_cache(ops);
524                 rules_ops_put(ops);
525                 return 0;
526         }
527 
528         err = -ENOENT;
529 errout:
530         rules_ops_put(ops);
531         return err;
532 }
533 
534 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
535                                          struct fib_rule *rule)
536 {
537         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
538                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
539                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
540                          + nla_total_size(4) /* FRA_PRIORITY */
541                          + nla_total_size(4) /* FRA_TABLE */
542                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
543                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
544                          + nla_total_size(4) /* FRA_FWMARK */
545                          + nla_total_size(4); /* FRA_FWMASK */
546 
547         if (ops->nlmsg_payload)
548                 payload += ops->nlmsg_payload(rule);
549 
550         return payload;
551 }
552 
553 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
554                             u32 pid, u32 seq, int type, int flags,
555                             struct fib_rules_ops *ops)
556 {
557         struct nlmsghdr *nlh;
558         struct fib_rule_hdr *frh;
559 
560         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
561         if (nlh == NULL)
562                 return -EMSGSIZE;
563 
564         frh = nlmsg_data(nlh);
565         frh->family = ops->family;
566         frh->table = rule->table;
567         if (nla_put_u32(skb, FRA_TABLE, rule->table))
568                 goto nla_put_failure;
569         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
570                 goto nla_put_failure;
571         frh->res1 = 0;
572         frh->res2 = 0;
573         frh->action = rule->action;
574         frh->flags = rule->flags;
575 
576         if (rule->action == FR_ACT_GOTO &&
577             rcu_access_pointer(rule->ctarget) == NULL)
578                 frh->flags |= FIB_RULE_UNRESOLVED;
579 
580         if (rule->iifname[0]) {
581                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
582                         goto nla_put_failure;
583                 if (rule->iifindex == -1)
584                         frh->flags |= FIB_RULE_IIF_DETACHED;
585         }
586 
587         if (rule->oifname[0]) {
588                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
589                         goto nla_put_failure;
590                 if (rule->oifindex == -1)
591                         frh->flags |= FIB_RULE_OIF_DETACHED;
592         }
593 
594         if ((rule->pref &&
595              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
596             (rule->mark &&
597              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
598             ((rule->mark_mask || rule->mark) &&
599              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
600             (rule->target &&
601              nla_put_u32(skb, FRA_GOTO, rule->target)))
602                 goto nla_put_failure;
603 
604         if (rule->suppress_ifgroup != -1) {
605                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
606                         goto nla_put_failure;
607         }
608 
609         if (ops->fill(rule, skb, frh) < 0)
610                 goto nla_put_failure;
611 
612         return nlmsg_end(skb, nlh);
613 
614 nla_put_failure:
615         nlmsg_cancel(skb, nlh);
616         return -EMSGSIZE;
617 }
618 
619 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
620                       struct fib_rules_ops *ops)
621 {
622         int idx = 0;
623         struct fib_rule *rule;
624 
625         rcu_read_lock();
626         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
627                 if (idx < cb->args[1])
628                         goto skip;
629 
630                 if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
631                                      cb->nlh->nlmsg_seq, RTM_NEWRULE,
632                                      NLM_F_MULTI, ops) < 0)
633                         break;
634 skip:
635                 idx++;
636         }
637         rcu_read_unlock();
638         cb->args[1] = idx;
639         rules_ops_put(ops);
640 
641         return skb->len;
642 }
643 
644 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
645 {
646         struct net *net = sock_net(skb->sk);
647         struct fib_rules_ops *ops;
648         int idx = 0, family;
649 
650         family = rtnl_msg_family(cb->nlh);
651         if (family != AF_UNSPEC) {
652                 /* Protocol specific dump request */
653                 ops = lookup_rules_ops(net, family);
654                 if (ops == NULL)
655                         return -EAFNOSUPPORT;
656 
657                 return dump_rules(skb, cb, ops);
658         }
659 
660         rcu_read_lock();
661         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
662                 if (idx < cb->args[0] || !try_module_get(ops->owner))
663                         goto skip;
664 
665                 if (dump_rules(skb, cb, ops) < 0)
666                         break;
667 
668                 cb->args[1] = 0;
669 skip:
670                 idx++;
671         }
672         rcu_read_unlock();
673         cb->args[0] = idx;
674 
675         return skb->len;
676 }
677 
678 static void notify_rule_change(int event, struct fib_rule *rule,
679                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
680                                u32 pid)
681 {
682         struct net *net;
683         struct sk_buff *skb;
684         int err = -ENOBUFS;
685 
686         net = ops->fro_net;
687         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
688         if (skb == NULL)
689                 goto errout;
690 
691         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
692         if (err < 0) {
693                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
694                 WARN_ON(err == -EMSGSIZE);
695                 kfree_skb(skb);
696                 goto errout;
697         }
698 
699         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
700         return;
701 errout:
702         if (err < 0)
703                 rtnl_set_sk_err(net, ops->nlgroup, err);
704 }
705 
706 static void attach_rules(struct list_head *rules, struct net_device *dev)
707 {
708         struct fib_rule *rule;
709 
710         list_for_each_entry(rule, rules, list) {
711                 if (rule->iifindex == -1 &&
712                     strcmp(dev->name, rule->iifname) == 0)
713                         rule->iifindex = dev->ifindex;
714                 if (rule->oifindex == -1 &&
715                     strcmp(dev->name, rule->oifname) == 0)
716                         rule->oifindex = dev->ifindex;
717         }
718 }
719 
720 static void detach_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 == dev->ifindex)
726                         rule->iifindex = -1;
727                 if (rule->oifindex == dev->ifindex)
728                         rule->oifindex = -1;
729         }
730 }
731 
732 
733 static int fib_rules_event(struct notifier_block *this, unsigned long event,
734                            void *ptr)
735 {
736         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
737         struct net *net = dev_net(dev);
738         struct fib_rules_ops *ops;
739 
740         ASSERT_RTNL();
741 
742         switch (event) {
743         case NETDEV_REGISTER:
744                 list_for_each_entry(ops, &net->rules_ops, list)
745                         attach_rules(&ops->rules_list, dev);
746                 break;
747 
748         case NETDEV_CHANGENAME:
749                 list_for_each_entry(ops, &net->rules_ops, list) {
750                         detach_rules(&ops->rules_list, dev);
751                         attach_rules(&ops->rules_list, dev);
752                 }
753                 break;
754 
755         case NETDEV_UNREGISTER:
756                 list_for_each_entry(ops, &net->rules_ops, list)
757                         detach_rules(&ops->rules_list, dev);
758                 break;
759         }
760 
761         return NOTIFY_DONE;
762 }
763 
764 static struct notifier_block fib_rules_notifier = {
765         .notifier_call = fib_rules_event,
766 };
767 
768 static int __net_init fib_rules_net_init(struct net *net)
769 {
770         INIT_LIST_HEAD(&net->rules_ops);
771         spin_lock_init(&net->rules_mod_lock);
772         return 0;
773 }
774 
775 static struct pernet_operations fib_rules_net_ops = {
776         .init = fib_rules_net_init,
777 };
778 
779 static int __init fib_rules_init(void)
780 {
781         int err;
782         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
783         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
784         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
785 
786         err = register_pernet_subsys(&fib_rules_net_ops);
787         if (err < 0)
788                 goto fail;
789 
790         err = register_netdevice_notifier(&fib_rules_notifier);
791         if (err < 0)
792                 goto fail_unregister;
793 
794         return 0;
795 
796 fail_unregister:
797         unregister_pernet_subsys(&fib_rules_net_ops);
798 fail:
799         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
800         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
801         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
802         return err;
803 }
804 
805 subsys_initcall(fib_rules_init);
806 

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