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>
19 #include <net/ip_tunnels.h>
21 int fib_default_rule_add(struct fib_rules_ops *ops,
22 u32 pref, u32 table, u32 flags)
26 r = kzalloc(ops->rule_size, GFP_KERNEL);
30 atomic_set(&r->refcnt, 1);
31 r->action = FR_ACT_TO_TBL;
35 r->fr_net = ops->fro_net;
37 r->suppress_prefixlen = -1;
38 r->suppress_ifgroup = -1;
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);
45 EXPORT_SYMBOL(fib_default_rule_add);
47 static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
49 struct list_head *pos;
50 struct fib_rule *rule;
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);
57 return rule->pref - 1;
64 static void notify_rule_change(int event, struct fib_rule *rule,
65 struct fib_rules_ops *ops, struct nlmsghdr *nlh,
68 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
70 struct fib_rules_ops *ops;
73 list_for_each_entry_rcu(ops, &net->rules_ops, list) {
74 if (ops->family == family) {
75 if (!try_module_get(ops->owner))
86 static void rules_ops_put(struct fib_rules_ops *ops)
89 module_put(ops->owner);
92 static void flush_route_cache(struct fib_rules_ops *ops)
95 ops->flush_cache(ops);
98 static int __fib_rules_register(struct fib_rules_ops *ops)
101 struct fib_rules_ops *o;
106 if (ops->rule_size < sizeof(struct fib_rule))
109 if (ops->match == NULL || ops->configure == NULL ||
110 ops->compare == NULL || ops->fill == NULL ||
114 spin_lock(&net->rules_mod_lock);
115 list_for_each_entry(o, &net->rules_ops, list)
116 if (ops->family == o->family)
119 list_add_tail_rcu(&ops->list, &net->rules_ops);
122 spin_unlock(&net->rules_mod_lock);
127 struct fib_rules_ops *
128 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
130 struct fib_rules_ops *ops;
133 ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
135 return ERR_PTR(-ENOMEM);
137 INIT_LIST_HEAD(&ops->rules_list);
140 err = __fib_rules_register(ops);
148 EXPORT_SYMBOL_GPL(fib_rules_register);
150 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
152 struct fib_rule *rule, *tmp;
154 list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
155 list_del_rcu(&rule->list);
162 void fib_rules_unregister(struct fib_rules_ops *ops)
164 struct net *net = ops->fro_net;
166 spin_lock(&net->rules_mod_lock);
167 list_del_rcu(&ops->list);
168 spin_unlock(&net->rules_mod_lock);
170 fib_rules_cleanup_ops(ops);
173 EXPORT_SYMBOL_GPL(fib_rules_unregister);
175 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
176 struct flowi *fl, int flags)
180 if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
183 if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
186 if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
189 if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
192 ret = ops->match(rule, fl, flags);
194 return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
197 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
198 int flags, struct fib_lookup_arg *arg)
200 struct fib_rule *rule;
205 list_for_each_entry_rcu(rule, &ops->rules_list, list) {
207 if (!fib_rule_match(rule, ops, fl, flags))
210 if (rule->action == FR_ACT_GOTO) {
211 struct fib_rule *target;
213 target = rcu_dereference(rule->ctarget);
214 if (target == NULL) {
220 } else if (rule->action == FR_ACT_NOP)
223 err = ops->action(rule, fl, flags, arg);
225 if (!err && ops->suppress && ops->suppress(rule, arg))
228 if (err != -EAGAIN) {
229 if ((arg->flags & FIB_LOOKUP_NOREF) ||
230 likely(atomic_inc_not_zero(&rule->refcnt))) {
244 EXPORT_SYMBOL_GPL(fib_rules_lookup);
246 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
247 struct fib_rules_ops *ops)
252 if (tb[FRA_SRC] == NULL ||
253 frh->src_len > (ops->addr_size * 8) ||
254 nla_len(tb[FRA_SRC]) != ops->addr_size)
258 if (tb[FRA_DST] == NULL ||
259 frh->dst_len > (ops->addr_size * 8) ||
260 nla_len(tb[FRA_DST]) != ops->addr_size)
268 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
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;
277 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
280 ops = lookup_rules_ops(net, frh->family);
286 err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
290 err = validate_rulemsg(frh, tb, ops);
294 rule = kzalloc(ops->rule_size, GFP_KERNEL);
301 rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
302 : fib_default_rule_pref(ops);
304 if (tb[FRA_IIFNAME]) {
305 struct net_device *dev;
308 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
309 dev = __dev_get_by_name(net, rule->iifname);
311 rule->iifindex = dev->ifindex;
314 if (tb[FRA_OIFNAME]) {
315 struct net_device *dev;
318 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
319 dev = __dev_get_by_name(net, rule->oifname);
321 rule->oifindex = dev->ifindex;
324 if (tb[FRA_FWMARK]) {
325 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
327 /* compatibility: if the mark value is non-zero all bits
328 * are compared unless a mask is explicitly specified.
330 rule->mark_mask = 0xFFFFFFFF;
334 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
337 rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
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]);
345 rule->suppress_prefixlen = -1;
347 if (tb[FRA_SUPPRESS_IFGROUP])
348 rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
350 rule->suppress_ifgroup = -1;
354 if (rule->action != FR_ACT_GOTO)
357 rule->target = nla_get_u32(tb[FRA_GOTO]);
358 /* Backward jumps are prohibited to avoid endless loops */
359 if (rule->target <= rule->pref)
362 list_for_each_entry(r, &ops->rules_list, list) {
363 if (r->pref == rule->target) {
364 RCU_INIT_POINTER(rule->ctarget, r);
369 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
371 } else if (rule->action == FR_ACT_GOTO)
374 err = ops->configure(rule, skb, frh, tb);
378 list_for_each_entry(r, &ops->rules_list, list) {
379 if (r->pref > rule->pref)
387 list_add_rcu(&rule->list, &last->list);
389 list_add_rcu(&rule->list, &ops->rules_list);
391 if (ops->unresolved_rules) {
393 * There are unresolved goto rules in the list, check if
394 * any of them are pointing to this new rule.
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)
407 if (rule->action == FR_ACT_GOTO)
408 ops->nr_goto_rules++;
411 ops->unresolved_rules++;
414 ip_tunnel_need_metadata();
416 notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
417 flush_route_cache(ops);
428 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
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];
437 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
440 ops = lookup_rules_ops(net, frh->family);
446 err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
450 err = validate_rulemsg(frh, tb, ops);
454 list_for_each_entry(rule, &ops->rules_list, list) {
455 if (frh->action && (frh->action != rule->action))
458 if (frh_get_table(frh, tb) &&
459 (frh_get_table(frh, tb) != rule->table))
462 if (tb[FRA_PRIORITY] &&
463 (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
466 if (tb[FRA_IIFNAME] &&
467 nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
470 if (tb[FRA_OIFNAME] &&
471 nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
474 if (tb[FRA_FWMARK] &&
475 (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
478 if (tb[FRA_FWMASK] &&
479 (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
482 if (tb[FRA_TUN_ID] &&
483 (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
486 if (!ops->compare(rule, frh, tb))
489 if (rule->flags & FIB_RULE_PERMANENT) {
495 err = ops->delete(rule);
501 ip_tunnel_unneed_metadata();
503 list_del_rcu(&rule->list);
505 if (rule->action == FR_ACT_GOTO) {
506 ops->nr_goto_rules--;
507 if (rtnl_dereference(rule->ctarget) == NULL)
508 ops->unresolved_rules--;
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.
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++;
526 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
527 NETLINK_CB(skb).portid);
529 flush_route_cache(ops);
540 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
541 struct fib_rule *rule)
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 */
554 if (ops->nlmsg_payload)
555 payload += ops->nlmsg_payload(rule);
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)
564 struct nlmsghdr *nlh;
565 struct fib_rule_hdr *frh;
567 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
571 frh = nlmsg_data(nlh);
572 frh->family = ops->family;
573 frh->table = rule->table < 256 ? rule->table : RT_TABLE_COMPAT;
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;
580 frh->action = rule->action;
581 frh->flags = rule->flags;
583 if (rule->action == FR_ACT_GOTO &&
584 rcu_access_pointer(rule->ctarget) == NULL)
585 frh->flags |= FIB_RULE_UNRESOLVED;
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;
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;
602 nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
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)) ||
608 nla_put_u32(skb, FRA_GOTO, rule->target)) ||
610 nla_put_be64(skb, FRA_TUN_ID, rule->tun_id)))
611 goto nla_put_failure;
613 if (rule->suppress_ifgroup != -1) {
614 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
615 goto nla_put_failure;
618 if (ops->fill(rule, skb, frh) < 0)
619 goto nla_put_failure;
625 nlmsg_cancel(skb, nlh);
629 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
630 struct fib_rules_ops *ops)
633 struct fib_rule *rule;
637 list_for_each_entry_rcu(rule, &ops->rules_list, list) {
638 if (idx < cb->args[1])
641 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
642 cb->nlh->nlmsg_seq, RTM_NEWRULE,
656 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
658 struct net *net = sock_net(skb->sk);
659 struct fib_rules_ops *ops;
662 family = rtnl_msg_family(cb->nlh);
663 if (family != AF_UNSPEC) {
664 /* Protocol specific dump request */
665 ops = lookup_rules_ops(net, family);
667 return -EAFNOSUPPORT;
669 dump_rules(skb, cb, ops);
675 list_for_each_entry_rcu(ops, &net->rules_ops, list) {
676 if (idx < cb->args[0] || !try_module_get(ops->owner))
679 if (dump_rules(skb, cb, ops) < 0)
692 static void notify_rule_change(int event, struct fib_rule *rule,
693 struct fib_rules_ops *ops, struct nlmsghdr *nlh,
701 skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
705 err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
707 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
708 WARN_ON(err == -EMSGSIZE);
713 rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
717 rtnl_set_sk_err(net, ops->nlgroup, err);
720 static void attach_rules(struct list_head *rules, struct net_device *dev)
722 struct fib_rule *rule;
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;
734 static void detach_rules(struct list_head *rules, struct net_device *dev)
736 struct fib_rule *rule;
738 list_for_each_entry(rule, rules, list) {
739 if (rule->iifindex == dev->ifindex)
741 if (rule->oifindex == dev->ifindex)
747 static int fib_rules_event(struct notifier_block *this, unsigned long event,
750 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
751 struct net *net = dev_net(dev);
752 struct fib_rules_ops *ops;
757 case NETDEV_REGISTER:
758 list_for_each_entry(ops, &net->rules_ops, list)
759 attach_rules(&ops->rules_list, dev);
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);
769 case NETDEV_UNREGISTER:
770 list_for_each_entry(ops, &net->rules_ops, list)
771 detach_rules(&ops->rules_list, dev);
778 static struct notifier_block fib_rules_notifier = {
779 .notifier_call = fib_rules_event,
782 static int __net_init fib_rules_net_init(struct net *net)
784 INIT_LIST_HEAD(&net->rules_ops);
785 spin_lock_init(&net->rules_mod_lock);
789 static struct pernet_operations fib_rules_net_ops = {
790 .init = fib_rules_net_init,
793 static int __init fib_rules_init(void)
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);
800 err = register_pernet_subsys(&fib_rules_net_ops);
804 err = register_netdevice_notifier(&fib_rules_notifier);
806 goto fail_unregister;
811 unregister_pernet_subsys(&fib_rules_net_ops);
813 rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
814 rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
815 rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
819 subsys_initcall(fib_rules_init);