2 * net/core/fib_rules.c Generic Routing Rules
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.
8 * Authors: Thomas Graf <tgraf@suug.ch>
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>
18 #include <net/fib_rules.h>
20 int fib_default_rule_add(struct fib_rules_ops *ops,
21 u32 pref, u32 table, u32 flags)
25 r = kzalloc(ops->rule_size, GFP_KERNEL);
29 atomic_set(&r->refcnt, 1);
30 r->action = FR_ACT_TO_TBL;
34 r->fr_net = hold_net(ops->fro_net);
36 /* The lock is not required here, the list in unreacheable
37 * at the moment this function is called */
38 list_add_tail(&r->list, &ops->rules_list);
41 EXPORT_SYMBOL(fib_default_rule_add);
43 u32 fib_default_rule_pref(struct fib_rules_ops *ops)
45 struct list_head *pos;
46 struct fib_rule *rule;
48 if (!list_empty(&ops->rules_list)) {
49 pos = ops->rules_list.next;
50 if (pos->next != &ops->rules_list) {
51 rule = list_entry(pos->next, struct fib_rule, list);
53 return rule->pref - 1;
59 EXPORT_SYMBOL(fib_default_rule_pref);
61 static void notify_rule_change(int event, struct fib_rule *rule,
62 struct fib_rules_ops *ops, struct nlmsghdr *nlh,
65 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
67 struct fib_rules_ops *ops;
70 list_for_each_entry_rcu(ops, &net->rules_ops, list) {
71 if (ops->family == family) {
72 if (!try_module_get(ops->owner))
83 static void rules_ops_put(struct fib_rules_ops *ops)
86 module_put(ops->owner);
89 static void flush_route_cache(struct fib_rules_ops *ops)
92 ops->flush_cache(ops);
95 static int __fib_rules_register(struct fib_rules_ops *ops)
98 struct fib_rules_ops *o;
103 if (ops->rule_size < sizeof(struct fib_rule))
106 if (ops->match == NULL || ops->configure == NULL ||
107 ops->compare == NULL || ops->fill == NULL ||
111 spin_lock(&net->rules_mod_lock);
112 list_for_each_entry(o, &net->rules_ops, list)
113 if (ops->family == o->family)
117 list_add_tail_rcu(&ops->list, &net->rules_ops);
120 spin_unlock(&net->rules_mod_lock);
125 struct fib_rules_ops *
126 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
128 struct fib_rules_ops *ops;
131 ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
133 return ERR_PTR(-ENOMEM);
135 INIT_LIST_HEAD(&ops->rules_list);
138 err = __fib_rules_register(ops);
146 EXPORT_SYMBOL_GPL(fib_rules_register);
148 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
150 struct fib_rule *rule, *tmp;
152 list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
153 list_del_rcu(&rule->list);
160 static void fib_rules_put_rcu(struct rcu_head *head)
162 struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
163 struct net *net = ops->fro_net;
169 void fib_rules_unregister(struct fib_rules_ops *ops)
171 struct net *net = ops->fro_net;
173 spin_lock(&net->rules_mod_lock);
174 list_del_rcu(&ops->list);
175 fib_rules_cleanup_ops(ops);
176 spin_unlock(&net->rules_mod_lock);
178 call_rcu(&ops->rcu, fib_rules_put_rcu);
180 EXPORT_SYMBOL_GPL(fib_rules_unregister);
182 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
183 struct flowi *fl, int flags)
187 if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
190 if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
193 if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
196 ret = ops->match(rule, fl, flags);
198 return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
201 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
202 int flags, struct fib_lookup_arg *arg)
204 struct fib_rule *rule;
209 list_for_each_entry_rcu(rule, &ops->rules_list, list) {
211 if (!fib_rule_match(rule, ops, fl, flags))
214 if (rule->action == FR_ACT_GOTO) {
215 struct fib_rule *target;
217 target = rcu_dereference(rule->ctarget);
218 if (target == NULL) {
224 } else if (rule->action == FR_ACT_NOP)
227 err = ops->action(rule, fl, flags, arg);
229 if (err != -EAGAIN) {
230 if ((arg->flags & FIB_LOOKUP_NOREF) ||
231 likely(atomic_inc_not_zero(&rule->refcnt))) {
245 EXPORT_SYMBOL_GPL(fib_rules_lookup);
247 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
248 struct fib_rules_ops *ops)
253 if (tb[FRA_SRC] == NULL ||
254 frh->src_len > (ops->addr_size * 8) ||
255 nla_len(tb[FRA_SRC]) != ops->addr_size)
259 if (tb[FRA_DST] == NULL ||
260 frh->dst_len > (ops->addr_size * 8) ||
261 nla_len(tb[FRA_DST]) != ops->addr_size)
269 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
271 struct net *net = sock_net(skb->sk);
272 struct fib_rule_hdr *frh = nlmsg_data(nlh);
273 struct fib_rules_ops *ops = NULL;
274 struct fib_rule *rule, *r, *last = NULL;
275 struct nlattr *tb[FRA_MAX+1];
276 int err = -EINVAL, unresolved = 0;
278 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
281 ops = lookup_rules_ops(net, frh->family);
287 err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
291 err = validate_rulemsg(frh, tb, ops);
295 rule = kzalloc(ops->rule_size, GFP_KERNEL);
300 rule->fr_net = hold_net(net);
302 if (tb[FRA_PRIORITY])
303 rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
305 if (tb[FRA_IIFNAME]) {
306 struct net_device *dev;
309 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
310 dev = __dev_get_by_name(net, rule->iifname);
312 rule->iifindex = dev->ifindex;
315 if (tb[FRA_OIFNAME]) {
316 struct net_device *dev;
319 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
320 dev = __dev_get_by_name(net, rule->oifname);
322 rule->oifindex = dev->ifindex;
325 if (tb[FRA_FWMARK]) {
326 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
328 /* compatibility: if the mark value is non-zero all bits
329 * are compared unless a mask is explicitly specified.
331 rule->mark_mask = 0xFFFFFFFF;
335 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
337 rule->action = frh->action;
338 rule->flags = frh->flags;
339 rule->table = frh_get_table(frh, tb);
341 if (!tb[FRA_PRIORITY] && ops->default_pref)
342 rule->pref = ops->default_pref(ops);
346 if (rule->action != FR_ACT_GOTO)
349 rule->target = nla_get_u32(tb[FRA_GOTO]);
350 /* Backward jumps are prohibited to avoid endless loops */
351 if (rule->target <= rule->pref)
354 list_for_each_entry(r, &ops->rules_list, list) {
355 if (r->pref == rule->target) {
356 RCU_INIT_POINTER(rule->ctarget, r);
361 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
363 } else if (rule->action == FR_ACT_GOTO)
366 err = ops->configure(rule, skb, frh, tb);
370 list_for_each_entry(r, &ops->rules_list, list) {
371 if (r->pref > rule->pref)
379 list_add_rcu(&rule->list, &last->list);
381 list_add_rcu(&rule->list, &ops->rules_list);
383 if (ops->unresolved_rules) {
385 * There are unresolved goto rules in the list, check if
386 * any of them are pointing to this new rule.
388 list_for_each_entry(r, &ops->rules_list, list) {
389 if (r->action == FR_ACT_GOTO &&
390 r->target == rule->pref &&
391 rtnl_dereference(r->ctarget) == NULL) {
392 rcu_assign_pointer(r->ctarget, rule);
393 if (--ops->unresolved_rules == 0)
399 if (rule->action == FR_ACT_GOTO)
400 ops->nr_goto_rules++;
403 ops->unresolved_rules++;
405 notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
406 flush_route_cache(ops);
411 release_net(rule->fr_net);
418 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
420 struct net *net = sock_net(skb->sk);
421 struct fib_rule_hdr *frh = nlmsg_data(nlh);
422 struct fib_rules_ops *ops = NULL;
423 struct fib_rule *rule, *tmp;
424 struct nlattr *tb[FRA_MAX+1];
427 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
430 ops = lookup_rules_ops(net, frh->family);
436 err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
440 err = validate_rulemsg(frh, tb, ops);
444 list_for_each_entry(rule, &ops->rules_list, list) {
445 if (frh->action && (frh->action != rule->action))
448 if (frh_get_table(frh, tb) &&
449 (frh_get_table(frh, tb) != rule->table))
452 if (tb[FRA_PRIORITY] &&
453 (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
456 if (tb[FRA_IIFNAME] &&
457 nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
460 if (tb[FRA_OIFNAME] &&
461 nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
464 if (tb[FRA_FWMARK] &&
465 (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
468 if (tb[FRA_FWMASK] &&
469 (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
472 if (!ops->compare(rule, frh, tb))
475 if (rule->flags & FIB_RULE_PERMANENT) {
480 list_del_rcu(&rule->list);
482 if (rule->action == FR_ACT_GOTO) {
483 ops->nr_goto_rules--;
484 if (rtnl_dereference(rule->ctarget) == NULL)
485 ops->unresolved_rules--;
489 * Check if this rule is a target to any of them. If so,
490 * disable them. As this operation is eventually very
491 * expensive, it is only performed if goto rules have
492 * actually been added.
494 if (ops->nr_goto_rules > 0) {
495 list_for_each_entry(tmp, &ops->rules_list, list) {
496 if (rtnl_dereference(tmp->ctarget) == rule) {
497 RCU_INIT_POINTER(tmp->ctarget, NULL);
498 ops->unresolved_rules++;
503 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
504 NETLINK_CB(skb).portid);
508 flush_route_cache(ops);
519 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
520 struct fib_rule *rule)
522 size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
523 + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
524 + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
525 + nla_total_size(4) /* FRA_PRIORITY */
526 + nla_total_size(4) /* FRA_TABLE */
527 + nla_total_size(4) /* FRA_FWMARK */
528 + nla_total_size(4); /* FRA_FWMASK */
530 if (ops->nlmsg_payload)
531 payload += ops->nlmsg_payload(rule);
536 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
537 u32 pid, u32 seq, int type, int flags,
538 struct fib_rules_ops *ops)
540 struct nlmsghdr *nlh;
541 struct fib_rule_hdr *frh;
543 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
547 frh = nlmsg_data(nlh);
548 frh->family = ops->family;
549 frh->table = rule->table;
550 if (nla_put_u32(skb, FRA_TABLE, rule->table))
551 goto nla_put_failure;
554 frh->action = rule->action;
555 frh->flags = rule->flags;
557 if (rule->action == FR_ACT_GOTO &&
558 rcu_access_pointer(rule->ctarget) == NULL)
559 frh->flags |= FIB_RULE_UNRESOLVED;
561 if (rule->iifname[0]) {
562 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
563 goto nla_put_failure;
564 if (rule->iifindex == -1)
565 frh->flags |= FIB_RULE_IIF_DETACHED;
568 if (rule->oifname[0]) {
569 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
570 goto nla_put_failure;
571 if (rule->oifindex == -1)
572 frh->flags |= FIB_RULE_OIF_DETACHED;
576 nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
578 nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
579 ((rule->mark_mask || rule->mark) &&
580 nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
582 nla_put_u32(skb, FRA_GOTO, rule->target)))
583 goto nla_put_failure;
584 if (ops->fill(rule, skb, frh) < 0)
585 goto nla_put_failure;
587 return nlmsg_end(skb, nlh);
590 nlmsg_cancel(skb, nlh);
594 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
595 struct fib_rules_ops *ops)
598 struct fib_rule *rule;
601 list_for_each_entry_rcu(rule, &ops->rules_list, list) {
602 if (idx < cb->args[1])
605 if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
606 cb->nlh->nlmsg_seq, RTM_NEWRULE,
607 NLM_F_MULTI, ops) < 0)
619 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
621 struct net *net = sock_net(skb->sk);
622 struct fib_rules_ops *ops;
625 family = rtnl_msg_family(cb->nlh);
626 if (family != AF_UNSPEC) {
627 /* Protocol specific dump request */
628 ops = lookup_rules_ops(net, family);
630 return -EAFNOSUPPORT;
632 return dump_rules(skb, cb, ops);
636 list_for_each_entry_rcu(ops, &net->rules_ops, list) {
637 if (idx < cb->args[0] || !try_module_get(ops->owner))
640 if (dump_rules(skb, cb, ops) < 0)
653 static void notify_rule_change(int event, struct fib_rule *rule,
654 struct fib_rules_ops *ops, struct nlmsghdr *nlh,
662 skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
666 err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
668 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
669 WARN_ON(err == -EMSGSIZE);
674 rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
678 rtnl_set_sk_err(net, ops->nlgroup, err);
681 static void attach_rules(struct list_head *rules, struct net_device *dev)
683 struct fib_rule *rule;
685 list_for_each_entry(rule, rules, list) {
686 if (rule->iifindex == -1 &&
687 strcmp(dev->name, rule->iifname) == 0)
688 rule->iifindex = dev->ifindex;
689 if (rule->oifindex == -1 &&
690 strcmp(dev->name, rule->oifname) == 0)
691 rule->oifindex = dev->ifindex;
695 static void detach_rules(struct list_head *rules, struct net_device *dev)
697 struct fib_rule *rule;
699 list_for_each_entry(rule, rules, list) {
700 if (rule->iifindex == dev->ifindex)
702 if (rule->oifindex == dev->ifindex)
708 static int fib_rules_event(struct notifier_block *this, unsigned long event,
711 struct net_device *dev = ptr;
712 struct net *net = dev_net(dev);
713 struct fib_rules_ops *ops;
718 case NETDEV_REGISTER:
719 list_for_each_entry(ops, &net->rules_ops, list)
720 attach_rules(&ops->rules_list, dev);
723 case NETDEV_CHANGENAME:
724 list_for_each_entry(ops, &net->rules_ops, list) {
725 detach_rules(&ops->rules_list, dev);
726 attach_rules(&ops->rules_list, dev);
730 case NETDEV_UNREGISTER:
731 list_for_each_entry(ops, &net->rules_ops, list)
732 detach_rules(&ops->rules_list, dev);
739 static struct notifier_block fib_rules_notifier = {
740 .notifier_call = fib_rules_event,
743 static int __net_init fib_rules_net_init(struct net *net)
745 INIT_LIST_HEAD(&net->rules_ops);
746 spin_lock_init(&net->rules_mod_lock);
750 static struct pernet_operations fib_rules_net_ops = {
751 .init = fib_rules_net_init,
754 static int __init fib_rules_init(void)
757 rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
758 rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
759 rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
761 err = register_pernet_subsys(&fib_rules_net_ops);
765 err = register_netdevice_notifier(&fib_rules_notifier);
767 goto fail_unregister;
772 unregister_pernet_subsys(&fib_rules_net_ops);
774 rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
775 rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
776 rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
780 subsys_initcall(fib_rules_init);