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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 #include <net/ip_tunnels.h>
 20 
 21 static const struct fib_kuid_range fib_kuid_range_unset = {
 22         KUIDT_INIT(0),
 23         KUIDT_INIT(~0),
 24 };
 25 
 26 bool fib_rule_matchall(const struct fib_rule *rule)
 27 {
 28         if (rule->iifindex || rule->oifindex || rule->mark || rule->tun_id ||
 29             rule->flags)
 30                 return false;
 31         if (rule->suppress_ifgroup != -1 || rule->suppress_prefixlen != -1)
 32                 return false;
 33         if (!uid_eq(rule->uid_range.start, fib_kuid_range_unset.start) ||
 34             !uid_eq(rule->uid_range.end, fib_kuid_range_unset.end))
 35                 return false;
 36         if (fib_rule_port_range_set(&rule->sport_range))
 37                 return false;
 38         if (fib_rule_port_range_set(&rule->dport_range))
 39                 return false;
 40         return true;
 41 }
 42 EXPORT_SYMBOL_GPL(fib_rule_matchall);
 43 
 44 int fib_default_rule_add(struct fib_rules_ops *ops,
 45                          u32 pref, u32 table, u32 flags)
 46 {
 47         struct fib_rule *r;
 48 
 49         r = kzalloc(ops->rule_size, GFP_KERNEL);
 50         if (r == NULL)
 51                 return -ENOMEM;
 52 
 53         refcount_set(&r->refcnt, 1);
 54         r->action = FR_ACT_TO_TBL;
 55         r->pref = pref;
 56         r->table = table;
 57         r->flags = flags;
 58         r->proto = RTPROT_KERNEL;
 59         r->fr_net = ops->fro_net;
 60         r->uid_range = fib_kuid_range_unset;
 61 
 62         r->suppress_prefixlen = -1;
 63         r->suppress_ifgroup = -1;
 64 
 65         /* The lock is not required here, the list in unreacheable
 66          * at the moment this function is called */
 67         list_add_tail(&r->list, &ops->rules_list);
 68         return 0;
 69 }
 70 EXPORT_SYMBOL(fib_default_rule_add);
 71 
 72 static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
 73 {
 74         struct list_head *pos;
 75         struct fib_rule *rule;
 76 
 77         if (!list_empty(&ops->rules_list)) {
 78                 pos = ops->rules_list.next;
 79                 if (pos->next != &ops->rules_list) {
 80                         rule = list_entry(pos->next, struct fib_rule, list);
 81                         if (rule->pref)
 82                                 return rule->pref - 1;
 83                 }
 84         }
 85 
 86         return 0;
 87 }
 88 
 89 static void notify_rule_change(int event, struct fib_rule *rule,
 90                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 91                                u32 pid);
 92 
 93 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
 94 {
 95         struct fib_rules_ops *ops;
 96 
 97         rcu_read_lock();
 98         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 99                 if (ops->family == family) {
100                         if (!try_module_get(ops->owner))
101                                 ops = NULL;
102                         rcu_read_unlock();
103                         return ops;
104                 }
105         }
106         rcu_read_unlock();
107 
108         return NULL;
109 }
110 
111 static void rules_ops_put(struct fib_rules_ops *ops)
112 {
113         if (ops)
114                 module_put(ops->owner);
115 }
116 
117 static void flush_route_cache(struct fib_rules_ops *ops)
118 {
119         if (ops->flush_cache)
120                 ops->flush_cache(ops);
121 }
122 
123 static int __fib_rules_register(struct fib_rules_ops *ops)
124 {
125         int err = -EEXIST;
126         struct fib_rules_ops *o;
127         struct net *net;
128 
129         net = ops->fro_net;
130 
131         if (ops->rule_size < sizeof(struct fib_rule))
132                 return -EINVAL;
133 
134         if (ops->match == NULL || ops->configure == NULL ||
135             ops->compare == NULL || ops->fill == NULL ||
136             ops->action == NULL)
137                 return -EINVAL;
138 
139         spin_lock(&net->rules_mod_lock);
140         list_for_each_entry(o, &net->rules_ops, list)
141                 if (ops->family == o->family)
142                         goto errout;
143 
144         list_add_tail_rcu(&ops->list, &net->rules_ops);
145         err = 0;
146 errout:
147         spin_unlock(&net->rules_mod_lock);
148 
149         return err;
150 }
151 
152 struct fib_rules_ops *
153 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
154 {
155         struct fib_rules_ops *ops;
156         int err;
157 
158         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
159         if (ops == NULL)
160                 return ERR_PTR(-ENOMEM);
161 
162         INIT_LIST_HEAD(&ops->rules_list);
163         ops->fro_net = net;
164 
165         err = __fib_rules_register(ops);
166         if (err) {
167                 kfree(ops);
168                 ops = ERR_PTR(err);
169         }
170 
171         return ops;
172 }
173 EXPORT_SYMBOL_GPL(fib_rules_register);
174 
175 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
176 {
177         struct fib_rule *rule, *tmp;
178 
179         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
180                 list_del_rcu(&rule->list);
181                 if (ops->delete)
182                         ops->delete(rule);
183                 fib_rule_put(rule);
184         }
185 }
186 
187 void fib_rules_unregister(struct fib_rules_ops *ops)
188 {
189         struct net *net = ops->fro_net;
190 
191         spin_lock(&net->rules_mod_lock);
192         list_del_rcu(&ops->list);
193         spin_unlock(&net->rules_mod_lock);
194 
195         fib_rules_cleanup_ops(ops);
196         kfree_rcu(ops, rcu);
197 }
198 EXPORT_SYMBOL_GPL(fib_rules_unregister);
199 
200 static int uid_range_set(struct fib_kuid_range *range)
201 {
202         return uid_valid(range->start) && uid_valid(range->end);
203 }
204 
205 static struct fib_kuid_range nla_get_kuid_range(struct nlattr **tb)
206 {
207         struct fib_rule_uid_range *in;
208         struct fib_kuid_range out;
209 
210         in = (struct fib_rule_uid_range *)nla_data(tb[FRA_UID_RANGE]);
211 
212         out.start = make_kuid(current_user_ns(), in->start);
213         out.end = make_kuid(current_user_ns(), in->end);
214 
215         return out;
216 }
217 
218 static int nla_put_uid_range(struct sk_buff *skb, struct fib_kuid_range *range)
219 {
220         struct fib_rule_uid_range out = {
221                 from_kuid_munged(current_user_ns(), range->start),
222                 from_kuid_munged(current_user_ns(), range->end)
223         };
224 
225         return nla_put(skb, FRA_UID_RANGE, sizeof(out), &out);
226 }
227 
228 static int nla_get_port_range(struct nlattr *pattr,
229                               struct fib_rule_port_range *port_range)
230 {
231         const struct fib_rule_port_range *pr = nla_data(pattr);
232 
233         if (!fib_rule_port_range_valid(pr))
234                 return -EINVAL;
235 
236         port_range->start = pr->start;
237         port_range->end = pr->end;
238 
239         return 0;
240 }
241 
242 static int nla_put_port_range(struct sk_buff *skb, int attrtype,
243                               struct fib_rule_port_range *range)
244 {
245         return nla_put(skb, attrtype, sizeof(*range), range);
246 }
247 
248 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
249                           struct flowi *fl, int flags,
250                           struct fib_lookup_arg *arg)
251 {
252         int ret = 0;
253 
254         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
255                 goto out;
256 
257         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
258                 goto out;
259 
260         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
261                 goto out;
262 
263         if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
264                 goto out;
265 
266         if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
267                 goto out;
268 
269         if (uid_lt(fl->flowi_uid, rule->uid_range.start) ||
270             uid_gt(fl->flowi_uid, rule->uid_range.end))
271                 goto out;
272 
273         ret = ops->match(rule, fl, flags);
274 out:
275         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
276 }
277 
278 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
279                      int flags, struct fib_lookup_arg *arg)
280 {
281         struct fib_rule *rule;
282         int err;
283 
284         rcu_read_lock();
285 
286         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
287 jumped:
288                 if (!fib_rule_match(rule, ops, fl, flags, arg))
289                         continue;
290 
291                 if (rule->action == FR_ACT_GOTO) {
292                         struct fib_rule *target;
293 
294                         target = rcu_dereference(rule->ctarget);
295                         if (target == NULL) {
296                                 continue;
297                         } else {
298                                 rule = target;
299                                 goto jumped;
300                         }
301                 } else if (rule->action == FR_ACT_NOP)
302                         continue;
303                 else
304                         err = ops->action(rule, fl, flags, arg);
305 
306                 if (!err && ops->suppress && ops->suppress(rule, arg))
307                         continue;
308 
309                 if (err != -EAGAIN) {
310                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
311                             likely(refcount_inc_not_zero(&rule->refcnt))) {
312                                 arg->rule = rule;
313                                 goto out;
314                         }
315                         break;
316                 }
317         }
318 
319         err = -ESRCH;
320 out:
321         rcu_read_unlock();
322 
323         return err;
324 }
325 EXPORT_SYMBOL_GPL(fib_rules_lookup);
326 
327 static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
328                                   enum fib_event_type event_type,
329                                   struct fib_rule *rule, int family)
330 {
331         struct fib_rule_notifier_info info = {
332                 .info.family = family,
333                 .rule = rule,
334         };
335 
336         return call_fib_notifier(nb, net, event_type, &info.info);
337 }
338 
339 static int call_fib_rule_notifiers(struct net *net,
340                                    enum fib_event_type event_type,
341                                    struct fib_rule *rule,
342                                    struct fib_rules_ops *ops,
343                                    struct netlink_ext_ack *extack)
344 {
345         struct fib_rule_notifier_info info = {
346                 .info.family = ops->family,
347                 .info.extack = extack,
348                 .rule = rule,
349         };
350 
351         ops->fib_rules_seq++;
352         return call_fib_notifiers(net, event_type, &info.info);
353 }
354 
355 /* Called with rcu_read_lock() */
356 int fib_rules_dump(struct net *net, struct notifier_block *nb, int family)
357 {
358         struct fib_rules_ops *ops;
359         struct fib_rule *rule;
360 
361         ops = lookup_rules_ops(net, family);
362         if (!ops)
363                 return -EAFNOSUPPORT;
364         list_for_each_entry_rcu(rule, &ops->rules_list, list)
365                 call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule,
366                                        family);
367         rules_ops_put(ops);
368 
369         return 0;
370 }
371 EXPORT_SYMBOL_GPL(fib_rules_dump);
372 
373 unsigned int fib_rules_seq_read(struct net *net, int family)
374 {
375         unsigned int fib_rules_seq;
376         struct fib_rules_ops *ops;
377 
378         ASSERT_RTNL();
379 
380         ops = lookup_rules_ops(net, family);
381         if (!ops)
382                 return 0;
383         fib_rules_seq = ops->fib_rules_seq;
384         rules_ops_put(ops);
385 
386         return fib_rules_seq;
387 }
388 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
389 
390 static struct fib_rule *rule_find(struct fib_rules_ops *ops,
391                                   struct fib_rule_hdr *frh,
392                                   struct nlattr **tb,
393                                   struct fib_rule *rule,
394                                   bool user_priority)
395 {
396         struct fib_rule *r;
397 
398         list_for_each_entry(r, &ops->rules_list, list) {
399                 if (rule->action && r->action != rule->action)
400                         continue;
401 
402                 if (rule->table && r->table != rule->table)
403                         continue;
404 
405                 if (user_priority && r->pref != rule->pref)
406                         continue;
407 
408                 if (rule->iifname[0] &&
409                     memcmp(r->iifname, rule->iifname, IFNAMSIZ))
410                         continue;
411 
412                 if (rule->oifname[0] &&
413                     memcmp(r->oifname, rule->oifname, IFNAMSIZ))
414                         continue;
415 
416                 if (rule->mark && r->mark != rule->mark)
417                         continue;
418 
419                 if (rule->suppress_ifgroup != -1 &&
420                     r->suppress_ifgroup != rule->suppress_ifgroup)
421                         continue;
422 
423                 if (rule->suppress_prefixlen != -1 &&
424                     r->suppress_prefixlen != rule->suppress_prefixlen)
425                         continue;
426 
427                 if (rule->mark_mask && r->mark_mask != rule->mark_mask)
428                         continue;
429 
430                 if (rule->tun_id && r->tun_id != rule->tun_id)
431                         continue;
432 
433                 if (r->fr_net != rule->fr_net)
434                         continue;
435 
436                 if (rule->l3mdev && r->l3mdev != rule->l3mdev)
437                         continue;
438 
439                 if (uid_range_set(&rule->uid_range) &&
440                     (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
441                     !uid_eq(r->uid_range.end, rule->uid_range.end)))
442                         continue;
443 
444                 if (rule->ip_proto && r->ip_proto != rule->ip_proto)
445                         continue;
446 
447                 if (rule->proto && r->proto != rule->proto)
448                         continue;
449 
450                 if (fib_rule_port_range_set(&rule->sport_range) &&
451                     !fib_rule_port_range_compare(&r->sport_range,
452                                                  &rule->sport_range))
453                         continue;
454 
455                 if (fib_rule_port_range_set(&rule->dport_range) &&
456                     !fib_rule_port_range_compare(&r->dport_range,
457                                                  &rule->dport_range))
458                         continue;
459 
460                 if (!ops->compare(r, frh, tb))
461                         continue;
462                 return r;
463         }
464 
465         return NULL;
466 }
467 
468 #ifdef CONFIG_NET_L3_MASTER_DEV
469 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
470                               struct netlink_ext_ack *extack)
471 {
472         nlrule->l3mdev = nla_get_u8(nla);
473         if (nlrule->l3mdev != 1) {
474                 NL_SET_ERR_MSG(extack, "Invalid l3mdev attribute");
475                 return -1;
476         }
477 
478         return 0;
479 }
480 #else
481 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
482                               struct netlink_ext_ack *extack)
483 {
484         NL_SET_ERR_MSG(extack, "l3mdev support is not enabled in kernel");
485         return -1;
486 }
487 #endif
488 
489 static int fib_nl2rule(struct sk_buff *skb, struct nlmsghdr *nlh,
490                        struct netlink_ext_ack *extack,
491                        struct fib_rules_ops *ops,
492                        struct nlattr *tb[],
493                        struct fib_rule **rule,
494                        bool *user_priority)
495 {
496         struct net *net = sock_net(skb->sk);
497         struct fib_rule_hdr *frh = nlmsg_data(nlh);
498         struct fib_rule *nlrule = NULL;
499         int err = -EINVAL;
500 
501         if (frh->src_len)
502                 if (!tb[FRA_SRC] ||
503                     frh->src_len > (ops->addr_size * 8) ||
504                     nla_len(tb[FRA_SRC]) != ops->addr_size) {
505                         NL_SET_ERR_MSG(extack, "Invalid source address");
506                         goto errout;
507         }
508 
509         if (frh->dst_len)
510                 if (!tb[FRA_DST] ||
511                     frh->dst_len > (ops->addr_size * 8) ||
512                     nla_len(tb[FRA_DST]) != ops->addr_size) {
513                         NL_SET_ERR_MSG(extack, "Invalid dst address");
514                         goto errout;
515         }
516 
517         nlrule = kzalloc(ops->rule_size, GFP_KERNEL);
518         if (!nlrule) {
519                 err = -ENOMEM;
520                 goto errout;
521         }
522         refcount_set(&nlrule->refcnt, 1);
523         nlrule->fr_net = net;
524 
525         if (tb[FRA_PRIORITY]) {
526                 nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
527                 *user_priority = true;
528         } else {
529                 nlrule->pref = fib_default_rule_pref(ops);
530         }
531 
532         nlrule->proto = tb[FRA_PROTOCOL] ?
533                 nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
534 
535         if (tb[FRA_IIFNAME]) {
536                 struct net_device *dev;
537 
538                 nlrule->iifindex = -1;
539                 nla_strlcpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
540                 dev = __dev_get_by_name(net, nlrule->iifname);
541                 if (dev)
542                         nlrule->iifindex = dev->ifindex;
543         }
544 
545         if (tb[FRA_OIFNAME]) {
546                 struct net_device *dev;
547 
548                 nlrule->oifindex = -1;
549                 nla_strlcpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
550                 dev = __dev_get_by_name(net, nlrule->oifname);
551                 if (dev)
552                         nlrule->oifindex = dev->ifindex;
553         }
554 
555         if (tb[FRA_FWMARK]) {
556                 nlrule->mark = nla_get_u32(tb[FRA_FWMARK]);
557                 if (nlrule->mark)
558                         /* compatibility: if the mark value is non-zero all bits
559                          * are compared unless a mask is explicitly specified.
560                          */
561                         nlrule->mark_mask = 0xFFFFFFFF;
562         }
563 
564         if (tb[FRA_FWMASK])
565                 nlrule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
566 
567         if (tb[FRA_TUN_ID])
568                 nlrule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
569 
570         err = -EINVAL;
571         if (tb[FRA_L3MDEV] &&
572             fib_nl2rule_l3mdev(tb[FRA_L3MDEV], nlrule, extack) < 0)
573                 goto errout_free;
574 
575         nlrule->action = frh->action;
576         nlrule->flags = frh->flags;
577         nlrule->table = frh_get_table(frh, tb);
578         if (tb[FRA_SUPPRESS_PREFIXLEN])
579                 nlrule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
580         else
581                 nlrule->suppress_prefixlen = -1;
582 
583         if (tb[FRA_SUPPRESS_IFGROUP])
584                 nlrule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
585         else
586                 nlrule->suppress_ifgroup = -1;
587 
588         if (tb[FRA_GOTO]) {
589                 if (nlrule->action != FR_ACT_GOTO) {
590                         NL_SET_ERR_MSG(extack, "Unexpected goto");
591                         goto errout_free;
592                 }
593 
594                 nlrule->target = nla_get_u32(tb[FRA_GOTO]);
595                 /* Backward jumps are prohibited to avoid endless loops */
596                 if (nlrule->target <= nlrule->pref) {
597                         NL_SET_ERR_MSG(extack, "Backward goto not supported");
598                         goto errout_free;
599                 }
600         } else if (nlrule->action == FR_ACT_GOTO) {
601                 NL_SET_ERR_MSG(extack, "Missing goto target for action goto");
602                 goto errout_free;
603         }
604 
605         if (nlrule->l3mdev && nlrule->table) {
606                 NL_SET_ERR_MSG(extack, "l3mdev and table are mutually exclusive");
607                 goto errout_free;
608         }
609 
610         if (tb[FRA_UID_RANGE]) {
611                 if (current_user_ns() != net->user_ns) {
612                         err = -EPERM;
613                         NL_SET_ERR_MSG(extack, "No permission to set uid");
614                         goto errout_free;
615                 }
616 
617                 nlrule->uid_range = nla_get_kuid_range(tb);
618 
619                 if (!uid_range_set(&nlrule->uid_range) ||
620                     !uid_lte(nlrule->uid_range.start, nlrule->uid_range.end)) {
621                         NL_SET_ERR_MSG(extack, "Invalid uid range");
622                         goto errout_free;
623                 }
624         } else {
625                 nlrule->uid_range = fib_kuid_range_unset;
626         }
627 
628         if (tb[FRA_IP_PROTO])
629                 nlrule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
630 
631         if (tb[FRA_SPORT_RANGE]) {
632                 err = nla_get_port_range(tb[FRA_SPORT_RANGE],
633                                          &nlrule->sport_range);
634                 if (err) {
635                         NL_SET_ERR_MSG(extack, "Invalid sport range");
636                         goto errout_free;
637                 }
638         }
639 
640         if (tb[FRA_DPORT_RANGE]) {
641                 err = nla_get_port_range(tb[FRA_DPORT_RANGE],
642                                          &nlrule->dport_range);
643                 if (err) {
644                         NL_SET_ERR_MSG(extack, "Invalid dport range");
645                         goto errout_free;
646                 }
647         }
648 
649         *rule = nlrule;
650 
651         return 0;
652 
653 errout_free:
654         kfree(nlrule);
655 errout:
656         return err;
657 }
658 
659 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
660                        struct nlattr **tb, struct fib_rule *rule)
661 {
662         struct fib_rule *r;
663 
664         list_for_each_entry(r, &ops->rules_list, list) {
665                 if (r->action != rule->action)
666                         continue;
667 
668                 if (r->table != rule->table)
669                         continue;
670 
671                 if (r->pref != rule->pref)
672                         continue;
673 
674                 if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
675                         continue;
676 
677                 if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
678                         continue;
679 
680                 if (r->mark != rule->mark)
681                         continue;
682 
683                 if (r->suppress_ifgroup != rule->suppress_ifgroup)
684                         continue;
685 
686                 if (r->suppress_prefixlen != rule->suppress_prefixlen)
687                         continue;
688 
689                 if (r->mark_mask != rule->mark_mask)
690                         continue;
691 
692                 if (r->tun_id != rule->tun_id)
693                         continue;
694 
695                 if (r->fr_net != rule->fr_net)
696                         continue;
697 
698                 if (r->l3mdev != rule->l3mdev)
699                         continue;
700 
701                 if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
702                     !uid_eq(r->uid_range.end, rule->uid_range.end))
703                         continue;
704 
705                 if (r->ip_proto != rule->ip_proto)
706                         continue;
707 
708                 if (r->proto != rule->proto)
709                         continue;
710 
711                 if (!fib_rule_port_range_compare(&r->sport_range,
712                                                  &rule->sport_range))
713                         continue;
714 
715                 if (!fib_rule_port_range_compare(&r->dport_range,
716                                                  &rule->dport_range))
717                         continue;
718 
719                 if (!ops->compare(r, frh, tb))
720                         continue;
721                 return 1;
722         }
723         return 0;
724 }
725 
726 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
727                    struct netlink_ext_ack *extack)
728 {
729         struct net *net = sock_net(skb->sk);
730         struct fib_rule_hdr *frh = nlmsg_data(nlh);
731         struct fib_rules_ops *ops = NULL;
732         struct fib_rule *rule = NULL, *r, *last = NULL;
733         struct nlattr *tb[FRA_MAX + 1];
734         int err = -EINVAL, unresolved = 0;
735         bool user_priority = false;
736 
737         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
738                 NL_SET_ERR_MSG(extack, "Invalid msg length");
739                 goto errout;
740         }
741 
742         ops = lookup_rules_ops(net, frh->family);
743         if (!ops) {
744                 err = -EAFNOSUPPORT;
745                 NL_SET_ERR_MSG(extack, "Rule family not supported");
746                 goto errout;
747         }
748 
749         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
750         if (err < 0) {
751                 NL_SET_ERR_MSG(extack, "Error parsing msg");
752                 goto errout;
753         }
754 
755         err = fib_nl2rule(skb, nlh, extack, ops, tb, &rule, &user_priority);
756         if (err)
757                 goto errout;
758 
759         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
760             rule_exists(ops, frh, tb, rule)) {
761                 err = -EEXIST;
762                 goto errout_free;
763         }
764 
765         err = ops->configure(rule, skb, frh, tb, extack);
766         if (err < 0)
767                 goto errout_free;
768 
769         err = call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule, ops,
770                                       extack);
771         if (err < 0)
772                 goto errout_free;
773 
774         list_for_each_entry(r, &ops->rules_list, list) {
775                 if (r->pref == rule->target) {
776                         RCU_INIT_POINTER(rule->ctarget, r);
777                         break;
778                 }
779         }
780 
781         if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
782                 unresolved = 1;
783 
784         list_for_each_entry(r, &ops->rules_list, list) {
785                 if (r->pref > rule->pref)
786                         break;
787                 last = r;
788         }
789 
790         if (last)
791                 list_add_rcu(&rule->list, &last->list);
792         else
793                 list_add_rcu(&rule->list, &ops->rules_list);
794 
795         if (ops->unresolved_rules) {
796                 /*
797                  * There are unresolved goto rules in the list, check if
798                  * any of them are pointing to this new rule.
799                  */
800                 list_for_each_entry(r, &ops->rules_list, list) {
801                         if (r->action == FR_ACT_GOTO &&
802                             r->target == rule->pref &&
803                             rtnl_dereference(r->ctarget) == NULL) {
804                                 rcu_assign_pointer(r->ctarget, rule);
805                                 if (--ops->unresolved_rules == 0)
806                                         break;
807                         }
808                 }
809         }
810 
811         if (rule->action == FR_ACT_GOTO)
812                 ops->nr_goto_rules++;
813 
814         if (unresolved)
815                 ops->unresolved_rules++;
816 
817         if (rule->tun_id)
818                 ip_tunnel_need_metadata();
819 
820         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
821         flush_route_cache(ops);
822         rules_ops_put(ops);
823         return 0;
824 
825 errout_free:
826         kfree(rule);
827 errout:
828         rules_ops_put(ops);
829         return err;
830 }
831 EXPORT_SYMBOL_GPL(fib_nl_newrule);
832 
833 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
834                    struct netlink_ext_ack *extack)
835 {
836         struct net *net = sock_net(skb->sk);
837         struct fib_rule_hdr *frh = nlmsg_data(nlh);
838         struct fib_rules_ops *ops = NULL;
839         struct fib_rule *rule = NULL, *r, *nlrule = NULL;
840         struct nlattr *tb[FRA_MAX+1];
841         int err = -EINVAL;
842         bool user_priority = false;
843 
844         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
845                 NL_SET_ERR_MSG(extack, "Invalid msg length");
846                 goto errout;
847         }
848 
849         ops = lookup_rules_ops(net, frh->family);
850         if (ops == NULL) {
851                 err = -EAFNOSUPPORT;
852                 NL_SET_ERR_MSG(extack, "Rule family not supported");
853                 goto errout;
854         }
855 
856         err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
857         if (err < 0) {
858                 NL_SET_ERR_MSG(extack, "Error parsing msg");
859                 goto errout;
860         }
861 
862         err = fib_nl2rule(skb, nlh, extack, ops, tb, &nlrule, &user_priority);
863         if (err)
864                 goto errout;
865 
866         rule = rule_find(ops, frh, tb, nlrule, user_priority);
867         if (!rule) {
868                 err = -ENOENT;
869                 goto errout;
870         }
871 
872         if (rule->flags & FIB_RULE_PERMANENT) {
873                 err = -EPERM;
874                 goto errout;
875         }
876 
877         if (ops->delete) {
878                 err = ops->delete(rule);
879                 if (err)
880                         goto errout;
881         }
882 
883         if (rule->tun_id)
884                 ip_tunnel_unneed_metadata();
885 
886         list_del_rcu(&rule->list);
887 
888         if (rule->action == FR_ACT_GOTO) {
889                 ops->nr_goto_rules--;
890                 if (rtnl_dereference(rule->ctarget) == NULL)
891                         ops->unresolved_rules--;
892         }
893 
894         /*
895          * Check if this rule is a target to any of them. If so,
896          * adjust to the next one with the same preference or
897          * disable them. As this operation is eventually very
898          * expensive, it is only performed if goto rules, except
899          * current if it is goto rule, have actually been added.
900          */
901         if (ops->nr_goto_rules > 0) {
902                 struct fib_rule *n;
903 
904                 n = list_next_entry(rule, list);
905                 if (&n->list == &ops->rules_list || n->pref != rule->pref)
906                         n = NULL;
907                 list_for_each_entry(r, &ops->rules_list, list) {
908                         if (rtnl_dereference(r->ctarget) != rule)
909                                 continue;
910                         rcu_assign_pointer(r->ctarget, n);
911                         if (!n)
912                                 ops->unresolved_rules++;
913                 }
914         }
915 
916         call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
917                                 NULL);
918         notify_rule_change(RTM_DELRULE, rule, ops, nlh,
919                            NETLINK_CB(skb).portid);
920         fib_rule_put(rule);
921         flush_route_cache(ops);
922         rules_ops_put(ops);
923         kfree(nlrule);
924         return 0;
925 
926 errout:
927         if (nlrule)
928                 kfree(nlrule);
929         rules_ops_put(ops);
930         return err;
931 }
932 EXPORT_SYMBOL_GPL(fib_nl_delrule);
933 
934 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
935                                          struct fib_rule *rule)
936 {
937         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
938                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
939                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
940                          + nla_total_size(4) /* FRA_PRIORITY */
941                          + nla_total_size(4) /* FRA_TABLE */
942                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
943                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
944                          + nla_total_size(4) /* FRA_FWMARK */
945                          + nla_total_size(4) /* FRA_FWMASK */
946                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
947                          + nla_total_size(sizeof(struct fib_kuid_range))
948                          + nla_total_size(1) /* FRA_PROTOCOL */
949                          + nla_total_size(1) /* FRA_IP_PROTO */
950                          + nla_total_size(sizeof(struct fib_rule_port_range)) /* FRA_SPORT_RANGE */
951                          + nla_total_size(sizeof(struct fib_rule_port_range)); /* FRA_DPORT_RANGE */
952 
953         if (ops->nlmsg_payload)
954                 payload += ops->nlmsg_payload(rule);
955 
956         return payload;
957 }
958 
959 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
960                             u32 pid, u32 seq, int type, int flags,
961                             struct fib_rules_ops *ops)
962 {
963         struct nlmsghdr *nlh;
964         struct fib_rule_hdr *frh;
965 
966         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
967         if (nlh == NULL)
968                 return -EMSGSIZE;
969 
970         frh = nlmsg_data(nlh);
971         frh->family = ops->family;
972         frh->table = rule->table;
973         if (nla_put_u32(skb, FRA_TABLE, rule->table))
974                 goto nla_put_failure;
975         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
976                 goto nla_put_failure;
977         frh->res1 = 0;
978         frh->res2 = 0;
979         frh->action = rule->action;
980         frh->flags = rule->flags;
981 
982         if (nla_put_u8(skb, FRA_PROTOCOL, rule->proto))
983                 goto nla_put_failure;
984 
985         if (rule->action == FR_ACT_GOTO &&
986             rcu_access_pointer(rule->ctarget) == NULL)
987                 frh->flags |= FIB_RULE_UNRESOLVED;
988 
989         if (rule->iifname[0]) {
990                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
991                         goto nla_put_failure;
992                 if (rule->iifindex == -1)
993                         frh->flags |= FIB_RULE_IIF_DETACHED;
994         }
995 
996         if (rule->oifname[0]) {
997                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
998                         goto nla_put_failure;
999                 if (rule->oifindex == -1)
1000                         frh->flags |= FIB_RULE_OIF_DETACHED;
1001         }
1002 
1003         if ((rule->pref &&
1004              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
1005             (rule->mark &&
1006              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
1007             ((rule->mark_mask || rule->mark) &&
1008              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
1009             (rule->target &&
1010              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
1011             (rule->tun_id &&
1012              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
1013             (rule->l3mdev &&
1014              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
1015             (uid_range_set(&rule->uid_range) &&
1016              nla_put_uid_range(skb, &rule->uid_range)) ||
1017             (fib_rule_port_range_set(&rule->sport_range) &&
1018              nla_put_port_range(skb, FRA_SPORT_RANGE, &rule->sport_range)) ||
1019             (fib_rule_port_range_set(&rule->dport_range) &&
1020              nla_put_port_range(skb, FRA_DPORT_RANGE, &rule->dport_range)) ||
1021             (rule->ip_proto && nla_put_u8(skb, FRA_IP_PROTO, rule->ip_proto)))
1022                 goto nla_put_failure;
1023 
1024         if (rule->suppress_ifgroup != -1) {
1025                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
1026                         goto nla_put_failure;
1027         }
1028 
1029         if (ops->fill(rule, skb, frh) < 0)
1030                 goto nla_put_failure;
1031 
1032         nlmsg_end(skb, nlh);
1033         return 0;
1034 
1035 nla_put_failure:
1036         nlmsg_cancel(skb, nlh);
1037         return -EMSGSIZE;
1038 }
1039 
1040 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
1041                       struct fib_rules_ops *ops)
1042 {
1043         int idx = 0;
1044         struct fib_rule *rule;
1045         int err = 0;
1046 
1047         rcu_read_lock();
1048         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
1049                 if (idx < cb->args[1])
1050                         goto skip;
1051 
1052                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
1053                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
1054                                        NLM_F_MULTI, ops);
1055                 if (err)
1056                         break;
1057 skip:
1058                 idx++;
1059         }
1060         rcu_read_unlock();
1061         cb->args[1] = idx;
1062         rules_ops_put(ops);
1063 
1064         return err;
1065 }
1066 
1067 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
1068 {
1069         struct net *net = sock_net(skb->sk);
1070         struct fib_rules_ops *ops;
1071         int idx = 0, family;
1072 
1073         family = rtnl_msg_family(cb->nlh);
1074         if (family != AF_UNSPEC) {
1075                 /* Protocol specific dump request */
1076                 ops = lookup_rules_ops(net, family);
1077                 if (ops == NULL)
1078                         return -EAFNOSUPPORT;
1079 
1080                 dump_rules(skb, cb, ops);
1081 
1082                 return skb->len;
1083         }
1084 
1085         rcu_read_lock();
1086         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
1087                 if (idx < cb->args[0] || !try_module_get(ops->owner))
1088                         goto skip;
1089 
1090                 if (dump_rules(skb, cb, ops) < 0)
1091                         break;
1092 
1093                 cb->args[1] = 0;
1094 skip:
1095                 idx++;
1096         }
1097         rcu_read_unlock();
1098         cb->args[0] = idx;
1099 
1100         return skb->len;
1101 }
1102 
1103 static void notify_rule_change(int event, struct fib_rule *rule,
1104                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
1105                                u32 pid)
1106 {
1107         struct net *net;
1108         struct sk_buff *skb;
1109         int err = -ENOBUFS;
1110 
1111         net = ops->fro_net;
1112         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
1113         if (skb == NULL)
1114                 goto errout;
1115 
1116         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
1117         if (err < 0) {
1118                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
1119                 WARN_ON(err == -EMSGSIZE);
1120                 kfree_skb(skb);
1121                 goto errout;
1122         }
1123 
1124         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
1125         return;
1126 errout:
1127         if (err < 0)
1128                 rtnl_set_sk_err(net, ops->nlgroup, err);
1129 }
1130 
1131 static void attach_rules(struct list_head *rules, struct net_device *dev)
1132 {
1133         struct fib_rule *rule;
1134 
1135         list_for_each_entry(rule, rules, list) {
1136                 if (rule->iifindex == -1 &&
1137                     strcmp(dev->name, rule->iifname) == 0)
1138                         rule->iifindex = dev->ifindex;
1139                 if (rule->oifindex == -1 &&
1140                     strcmp(dev->name, rule->oifname) == 0)
1141                         rule->oifindex = dev->ifindex;
1142         }
1143 }
1144 
1145 static void detach_rules(struct list_head *rules, struct net_device *dev)
1146 {
1147         struct fib_rule *rule;
1148 
1149         list_for_each_entry(rule, rules, list) {
1150                 if (rule->iifindex == dev->ifindex)
1151                         rule->iifindex = -1;
1152                 if (rule->oifindex == dev->ifindex)
1153                         rule->oifindex = -1;
1154         }
1155 }
1156 
1157 
1158 static int fib_rules_event(struct notifier_block *this, unsigned long event,
1159                            void *ptr)
1160 {
1161         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1162         struct net *net = dev_net(dev);
1163         struct fib_rules_ops *ops;
1164 
1165         ASSERT_RTNL();
1166 
1167         switch (event) {
1168         case NETDEV_REGISTER:
1169                 list_for_each_entry(ops, &net->rules_ops, list)
1170                         attach_rules(&ops->rules_list, dev);
1171                 break;
1172 
1173         case NETDEV_CHANGENAME:
1174                 list_for_each_entry(ops, &net->rules_ops, list) {
1175                         detach_rules(&ops->rules_list, dev);
1176                         attach_rules(&ops->rules_list, dev);
1177                 }
1178                 break;
1179 
1180         case NETDEV_UNREGISTER:
1181                 list_for_each_entry(ops, &net->rules_ops, list)
1182                         detach_rules(&ops->rules_list, dev);
1183                 break;
1184         }
1185 
1186         return NOTIFY_DONE;
1187 }
1188 
1189 static struct notifier_block fib_rules_notifier = {
1190         .notifier_call = fib_rules_event,
1191 };
1192 
1193 static int __net_init fib_rules_net_init(struct net *net)
1194 {
1195         INIT_LIST_HEAD(&net->rules_ops);
1196         spin_lock_init(&net->rules_mod_lock);
1197         return 0;
1198 }
1199 
1200 static void __net_exit fib_rules_net_exit(struct net *net)
1201 {
1202         WARN_ON_ONCE(!list_empty(&net->rules_ops));
1203 }
1204 
1205 static struct pernet_operations fib_rules_net_ops = {
1206         .init = fib_rules_net_init,
1207         .exit = fib_rules_net_exit,
1208 };
1209 
1210 static int __init fib_rules_init(void)
1211 {
1212         int err;
1213         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
1214         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
1215         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, 0);
1216 
1217         err = register_pernet_subsys(&fib_rules_net_ops);
1218         if (err < 0)
1219                 goto fail;
1220 
1221         err = register_netdevice_notifier(&fib_rules_notifier);
1222         if (err < 0)
1223                 goto fail_unregister;
1224 
1225         return 0;
1226 
1227 fail_unregister:
1228         unregister_pernet_subsys(&fib_rules_net_ops);
1229 fail:
1230         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
1231         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
1232         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
1233         return err;
1234 }
1235 
1236 subsys_initcall(fib_rules_init);
1237 

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