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 r->suppress_prefixlen = -1;
37 r->suppress_ifgroup = -1;
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);
44 EXPORT_SYMBOL(fib_default_rule_add);
46 u32 fib_default_rule_pref(struct fib_rules_ops *ops)
48 struct list_head *pos;
49 struct fib_rule *rule;
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);
56 return rule->pref - 1;
62 EXPORT_SYMBOL(fib_default_rule_pref);
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)
120 list_add_tail_rcu(&ops->list, &net->rules_ops);
123 spin_unlock(&net->rules_mod_lock);
128 struct fib_rules_ops *
129 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
131 struct fib_rules_ops *ops;
134 ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
136 return ERR_PTR(-ENOMEM);
138 INIT_LIST_HEAD(&ops->rules_list);
141 err = __fib_rules_register(ops);
149 EXPORT_SYMBOL_GPL(fib_rules_register);
151 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
153 struct fib_rule *rule, *tmp;
155 list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
156 list_del_rcu(&rule->list);
163 static void fib_rules_put_rcu(struct rcu_head *head)
165 struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
166 struct net *net = ops->fro_net;
172 void fib_rules_unregister(struct fib_rules_ops *ops)
174 struct net *net = ops->fro_net;
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);
181 call_rcu(&ops->rcu, fib_rules_put_rcu);
183 EXPORT_SYMBOL_GPL(fib_rules_unregister);
185 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
186 struct flowi *fl, int flags)
190 if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
193 if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
196 if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
199 ret = ops->match(rule, fl, flags);
201 return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
204 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
205 int flags, struct fib_lookup_arg *arg)
207 struct fib_rule *rule;
212 list_for_each_entry_rcu(rule, &ops->rules_list, list) {
214 if (!fib_rule_match(rule, ops, fl, flags))
217 if (rule->action == FR_ACT_GOTO) {
218 struct fib_rule *target;
220 target = rcu_dereference(rule->ctarget);
221 if (target == NULL) {
227 } else if (rule->action == FR_ACT_NOP)
230 err = ops->action(rule, fl, flags, arg);
232 if (!err && ops->suppress && ops->suppress(rule, arg))
235 if (err != -EAGAIN) {
236 if ((arg->flags & FIB_LOOKUP_NOREF) ||
237 likely(atomic_inc_not_zero(&rule->refcnt))) {
251 EXPORT_SYMBOL_GPL(fib_rules_lookup);
253 static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
254 struct fib_rules_ops *ops)
259 if (tb[FRA_SRC] == NULL ||
260 frh->src_len > (ops->addr_size * 8) ||
261 nla_len(tb[FRA_SRC]) != ops->addr_size)
265 if (tb[FRA_DST] == NULL ||
266 frh->dst_len > (ops->addr_size * 8) ||
267 nla_len(tb[FRA_DST]) != ops->addr_size)
275 static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
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;
284 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
287 ops = lookup_rules_ops(net, frh->family);
293 err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
297 err = validate_rulemsg(frh, tb, ops);
301 rule = kzalloc(ops->rule_size, GFP_KERNEL);
306 rule->fr_net = hold_net(net);
308 if (tb[FRA_PRIORITY])
309 rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
311 if (tb[FRA_IIFNAME]) {
312 struct net_device *dev;
315 nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
316 dev = __dev_get_by_name(net, rule->iifname);
318 rule->iifindex = dev->ifindex;
321 if (tb[FRA_OIFNAME]) {
322 struct net_device *dev;
325 nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
326 dev = __dev_get_by_name(net, rule->oifname);
328 rule->oifindex = dev->ifindex;
331 if (tb[FRA_FWMARK]) {
332 rule->mark = nla_get_u32(tb[FRA_FWMARK]);
334 /* compatibility: if the mark value is non-zero all bits
335 * are compared unless a mask is explicitly specified.
337 rule->mark_mask = 0xFFFFFFFF;
341 rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
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]);
349 rule->suppress_prefixlen = -1;
351 if (tb[FRA_SUPPRESS_IFGROUP])
352 rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
354 rule->suppress_ifgroup = -1;
356 if (!tb[FRA_PRIORITY] && ops->default_pref)
357 rule->pref = ops->default_pref(ops);
361 if (rule->action != FR_ACT_GOTO)
364 rule->target = nla_get_u32(tb[FRA_GOTO]);
365 /* Backward jumps are prohibited to avoid endless loops */
366 if (rule->target <= rule->pref)
369 list_for_each_entry(r, &ops->rules_list, list) {
370 if (r->pref == rule->target) {
371 RCU_INIT_POINTER(rule->ctarget, r);
376 if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
378 } else if (rule->action == FR_ACT_GOTO)
381 err = ops->configure(rule, skb, frh, tb);
385 list_for_each_entry(r, &ops->rules_list, list) {
386 if (r->pref > rule->pref)
394 list_add_rcu(&rule->list, &last->list);
396 list_add_rcu(&rule->list, &ops->rules_list);
398 if (ops->unresolved_rules) {
400 * There are unresolved goto rules in the list, check if
401 * any of them are pointing to this new rule.
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)
414 if (rule->action == FR_ACT_GOTO)
415 ops->nr_goto_rules++;
418 ops->unresolved_rules++;
420 notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
421 flush_route_cache(ops);
426 release_net(rule->fr_net);
433 static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh)
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];
442 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
445 ops = lookup_rules_ops(net, frh->family);
451 err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
455 err = validate_rulemsg(frh, tb, ops);
459 list_for_each_entry(rule, &ops->rules_list, list) {
460 if (frh->action && (frh->action != rule->action))
463 if (frh->table && (frh_get_table(frh, tb) != rule->table))
466 if (tb[FRA_PRIORITY] &&
467 (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
470 if (tb[FRA_IIFNAME] &&
471 nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
474 if (tb[FRA_OIFNAME] &&
475 nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
478 if (tb[FRA_FWMARK] &&
479 (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
482 if (tb[FRA_FWMASK] &&
483 (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
486 if (!ops->compare(rule, frh, tb))
489 if (rule->flags & FIB_RULE_PERMANENT) {
494 list_del_rcu(&rule->list);
496 if (rule->action == FR_ACT_GOTO) {
497 ops->nr_goto_rules--;
498 if (rtnl_dereference(rule->ctarget) == NULL)
499 ops->unresolved_rules--;
503 * Check if this rule is a target to any of them. If so,
504 * disable them. As this operation is eventually very
505 * expensive, it is only performed if goto rules have
506 * actually been added.
508 if (ops->nr_goto_rules > 0) {
509 list_for_each_entry(tmp, &ops->rules_list, list) {
510 if (rtnl_dereference(tmp->ctarget) == rule) {
511 RCU_INIT_POINTER(tmp->ctarget, NULL);
512 ops->unresolved_rules++;
517 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
518 NETLINK_CB(skb).portid);
522 flush_route_cache(ops);
533 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
534 struct fib_rule *rule)
536 size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
537 + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
538 + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
539 + nla_total_size(4) /* FRA_PRIORITY */
540 + nla_total_size(4) /* FRA_TABLE */
541 + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
542 + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
543 + nla_total_size(4) /* FRA_FWMARK */
544 + nla_total_size(4); /* FRA_FWMASK */
546 if (ops->nlmsg_payload)
547 payload += ops->nlmsg_payload(rule);
552 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
553 u32 pid, u32 seq, int type, int flags,
554 struct fib_rules_ops *ops)
556 struct nlmsghdr *nlh;
557 struct fib_rule_hdr *frh;
559 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
563 frh = nlmsg_data(nlh);
564 frh->family = ops->family;
565 frh->table = rule->table;
566 if (nla_put_u32(skb, FRA_TABLE, rule->table))
567 goto nla_put_failure;
568 if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
569 goto nla_put_failure;
572 frh->action = rule->action;
573 frh->flags = rule->flags;
575 if (rule->action == FR_ACT_GOTO &&
576 rcu_access_pointer(rule->ctarget) == NULL)
577 frh->flags |= FIB_RULE_UNRESOLVED;
579 if (rule->iifname[0]) {
580 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
581 goto nla_put_failure;
582 if (rule->iifindex == -1)
583 frh->flags |= FIB_RULE_IIF_DETACHED;
586 if (rule->oifname[0]) {
587 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
588 goto nla_put_failure;
589 if (rule->oifindex == -1)
590 frh->flags |= FIB_RULE_OIF_DETACHED;
594 nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
596 nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
597 ((rule->mark_mask || rule->mark) &&
598 nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
600 nla_put_u32(skb, FRA_GOTO, rule->target)))
601 goto nla_put_failure;
603 if (rule->suppress_ifgroup != -1) {
604 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
605 goto nla_put_failure;
608 if (ops->fill(rule, skb, frh) < 0)
609 goto nla_put_failure;
611 return nlmsg_end(skb, nlh);
614 nlmsg_cancel(skb, nlh);
618 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
619 struct fib_rules_ops *ops)
622 struct fib_rule *rule;
625 list_for_each_entry_rcu(rule, &ops->rules_list, list) {
626 if (idx < cb->args[1])
629 if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
630 cb->nlh->nlmsg_seq, RTM_NEWRULE,
631 NLM_F_MULTI, ops) < 0)
643 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
645 struct net *net = sock_net(skb->sk);
646 struct fib_rules_ops *ops;
649 family = rtnl_msg_family(cb->nlh);
650 if (family != AF_UNSPEC) {
651 /* Protocol specific dump request */
652 ops = lookup_rules_ops(net, family);
654 return -EAFNOSUPPORT;
656 return dump_rules(skb, cb, ops);
660 list_for_each_entry_rcu(ops, &net->rules_ops, list) {
661 if (idx < cb->args[0] || !try_module_get(ops->owner))
664 if (dump_rules(skb, cb, ops) < 0)
677 static void notify_rule_change(int event, struct fib_rule *rule,
678 struct fib_rules_ops *ops, struct nlmsghdr *nlh,
686 skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
690 err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
692 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
693 WARN_ON(err == -EMSGSIZE);
698 rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
702 rtnl_set_sk_err(net, ops->nlgroup, err);
705 static void attach_rules(struct list_head *rules, struct net_device *dev)
707 struct fib_rule *rule;
709 list_for_each_entry(rule, rules, list) {
710 if (rule->iifindex == -1 &&
711 strcmp(dev->name, rule->iifname) == 0)
712 rule->iifindex = dev->ifindex;
713 if (rule->oifindex == -1 &&
714 strcmp(dev->name, rule->oifname) == 0)
715 rule->oifindex = dev->ifindex;
719 static void detach_rules(struct list_head *rules, struct net_device *dev)
721 struct fib_rule *rule;
723 list_for_each_entry(rule, rules, list) {
724 if (rule->iifindex == dev->ifindex)
726 if (rule->oifindex == dev->ifindex)
732 static int fib_rules_event(struct notifier_block *this, unsigned long event,
735 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
736 struct net *net = dev_net(dev);
737 struct fib_rules_ops *ops;
742 case NETDEV_REGISTER:
743 list_for_each_entry(ops, &net->rules_ops, list)
744 attach_rules(&ops->rules_list, dev);
747 case NETDEV_UNREGISTER:
748 list_for_each_entry(ops, &net->rules_ops, list)
749 detach_rules(&ops->rules_list, dev);
756 static struct notifier_block fib_rules_notifier = {
757 .notifier_call = fib_rules_event,
760 static int __net_init fib_rules_net_init(struct net *net)
762 INIT_LIST_HEAD(&net->rules_ops);
763 spin_lock_init(&net->rules_mod_lock);
767 static struct pernet_operations fib_rules_net_ops = {
768 .init = fib_rules_net_init,
771 static int __init fib_rules_init(void)
774 rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
775 rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
776 rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
778 err = register_pernet_subsys(&fib_rules_net_ops);
782 err = register_netdevice_notifier(&fib_rules_notifier);
784 goto fail_unregister;
789 unregister_pernet_subsys(&fib_rules_net_ops);
791 rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
792 rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
793 rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
797 subsys_initcall(fib_rules_init);