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 <net/net_namespace.h>
17 #include <net/fib_rules.h>
19 int fib_default_rule_add(struct fib_rules_ops
*ops
,
20 u32 pref
, u32 table
, u32 flags
)
24 r
= kzalloc(ops
->rule_size
, GFP_KERNEL
);
28 atomic_set(&r
->refcnt
, 1);
29 r
->action
= FR_ACT_TO_TBL
;
33 r
->fr_net
= hold_net(ops
->fro_net
);
35 /* The lock is not required here, the list in unreacheable
36 * at the moment this function is called */
37 list_add_tail(&r
->list
, &ops
->rules_list
);
40 EXPORT_SYMBOL(fib_default_rule_add
);
42 u32
fib_default_rule_pref(struct fib_rules_ops
*ops
)
44 struct list_head
*pos
;
45 struct fib_rule
*rule
;
47 if (!list_empty(&ops
->rules_list
)) {
48 pos
= ops
->rules_list
.next
;
49 if (pos
->next
!= &ops
->rules_list
) {
50 rule
= list_entry(pos
->next
, struct fib_rule
, list
);
52 return rule
->pref
- 1;
58 EXPORT_SYMBOL(fib_default_rule_pref
);
60 static void notify_rule_change(int event
, struct fib_rule
*rule
,
61 struct fib_rules_ops
*ops
, struct nlmsghdr
*nlh
,
64 static struct fib_rules_ops
*lookup_rules_ops(struct net
*net
, int family
)
66 struct fib_rules_ops
*ops
;
69 list_for_each_entry_rcu(ops
, &net
->rules_ops
, list
) {
70 if (ops
->family
== family
) {
71 if (!try_module_get(ops
->owner
))
82 static void rules_ops_put(struct fib_rules_ops
*ops
)
85 module_put(ops
->owner
);
88 static void flush_route_cache(struct fib_rules_ops
*ops
)
91 ops
->flush_cache(ops
);
94 static int __fib_rules_register(struct fib_rules_ops
*ops
)
97 struct fib_rules_ops
*o
;
102 if (ops
->rule_size
< sizeof(struct fib_rule
))
105 if (ops
->match
== NULL
|| ops
->configure
== NULL
||
106 ops
->compare
== NULL
|| ops
->fill
== NULL
||
110 spin_lock(&net
->rules_mod_lock
);
111 list_for_each_entry(o
, &net
->rules_ops
, list
)
112 if (ops
->family
== o
->family
)
116 list_add_tail_rcu(&ops
->list
, &net
->rules_ops
);
119 spin_unlock(&net
->rules_mod_lock
);
124 struct fib_rules_ops
*
125 fib_rules_register(const struct fib_rules_ops
*tmpl
, struct net
*net
)
127 struct fib_rules_ops
*ops
;
130 ops
= kmemdup(tmpl
, sizeof(*ops
), GFP_KERNEL
);
132 return ERR_PTR(-ENOMEM
);
134 INIT_LIST_HEAD(&ops
->rules_list
);
137 err
= __fib_rules_register(ops
);
145 EXPORT_SYMBOL_GPL(fib_rules_register
);
147 static void fib_rules_cleanup_ops(struct fib_rules_ops
*ops
)
149 struct fib_rule
*rule
, *tmp
;
151 list_for_each_entry_safe(rule
, tmp
, &ops
->rules_list
, list
) {
152 list_del_rcu(&rule
->list
);
157 static void fib_rules_put_rcu(struct rcu_head
*head
)
159 struct fib_rules_ops
*ops
= container_of(head
, struct fib_rules_ops
, rcu
);
160 struct net
*net
= ops
->fro_net
;
166 void fib_rules_unregister(struct fib_rules_ops
*ops
)
168 struct net
*net
= ops
->fro_net
;
170 spin_lock(&net
->rules_mod_lock
);
171 list_del_rcu(&ops
->list
);
172 fib_rules_cleanup_ops(ops
);
173 spin_unlock(&net
->rules_mod_lock
);
175 call_rcu(&ops
->rcu
, fib_rules_put_rcu
);
177 EXPORT_SYMBOL_GPL(fib_rules_unregister
);
179 static int fib_rule_match(struct fib_rule
*rule
, struct fib_rules_ops
*ops
,
180 struct flowi
*fl
, int flags
)
184 if (rule
->iifindex
&& (rule
->iifindex
!= fl
->flowi_iif
))
187 if (rule
->oifindex
&& (rule
->oifindex
!= fl
->flowi_oif
))
190 if ((rule
->mark
^ fl
->flowi_mark
) & rule
->mark_mask
)
193 ret
= ops
->match(rule
, fl
, flags
);
195 return (rule
->flags
& FIB_RULE_INVERT
) ? !ret
: ret
;
198 int fib_rules_lookup(struct fib_rules_ops
*ops
, struct flowi
*fl
,
199 int flags
, struct fib_lookup_arg
*arg
)
201 struct fib_rule
*rule
;
206 list_for_each_entry_rcu(rule
, &ops
->rules_list
, list
) {
208 if (!fib_rule_match(rule
, ops
, fl
, flags
))
211 if (rule
->action
== FR_ACT_GOTO
) {
212 struct fib_rule
*target
;
214 target
= rcu_dereference(rule
->ctarget
);
215 if (target
== NULL
) {
221 } else if (rule
->action
== FR_ACT_NOP
)
224 err
= ops
->action(rule
, fl
, flags
, arg
);
226 if (err
!= -EAGAIN
) {
227 if ((arg
->flags
& FIB_LOOKUP_NOREF
) ||
228 likely(atomic_inc_not_zero(&rule
->refcnt
))) {
242 EXPORT_SYMBOL_GPL(fib_rules_lookup
);
244 static int validate_rulemsg(struct fib_rule_hdr
*frh
, struct nlattr
**tb
,
245 struct fib_rules_ops
*ops
)
250 if (tb
[FRA_SRC
] == NULL
||
251 frh
->src_len
> (ops
->addr_size
* 8) ||
252 nla_len(tb
[FRA_SRC
]) != ops
->addr_size
)
256 if (tb
[FRA_DST
] == NULL
||
257 frh
->dst_len
> (ops
->addr_size
* 8) ||
258 nla_len(tb
[FRA_DST
]) != ops
->addr_size
)
266 static int fib_nl_newrule(struct sk_buff
*skb
, struct nlmsghdr
* nlh
, void *arg
)
268 struct net
*net
= sock_net(skb
->sk
);
269 struct fib_rule_hdr
*frh
= nlmsg_data(nlh
);
270 struct fib_rules_ops
*ops
= NULL
;
271 struct fib_rule
*rule
, *r
, *last
= NULL
;
272 struct nlattr
*tb
[FRA_MAX
+1];
273 int err
= -EINVAL
, unresolved
= 0;
275 if (nlh
->nlmsg_len
< nlmsg_msg_size(sizeof(*frh
)))
278 ops
= lookup_rules_ops(net
, frh
->family
);
284 err
= nlmsg_parse(nlh
, sizeof(*frh
), tb
, FRA_MAX
, ops
->policy
);
288 err
= validate_rulemsg(frh
, tb
, ops
);
292 rule
= kzalloc(ops
->rule_size
, GFP_KERNEL
);
297 rule
->fr_net
= hold_net(net
);
299 if (tb
[FRA_PRIORITY
])
300 rule
->pref
= nla_get_u32(tb
[FRA_PRIORITY
]);
302 if (tb
[FRA_IIFNAME
]) {
303 struct net_device
*dev
;
306 nla_strlcpy(rule
->iifname
, tb
[FRA_IIFNAME
], IFNAMSIZ
);
307 dev
= __dev_get_by_name(net
, rule
->iifname
);
309 rule
->iifindex
= dev
->ifindex
;
312 if (tb
[FRA_OIFNAME
]) {
313 struct net_device
*dev
;
316 nla_strlcpy(rule
->oifname
, tb
[FRA_OIFNAME
], IFNAMSIZ
);
317 dev
= __dev_get_by_name(net
, rule
->oifname
);
319 rule
->oifindex
= dev
->ifindex
;
322 if (tb
[FRA_FWMARK
]) {
323 rule
->mark
= nla_get_u32(tb
[FRA_FWMARK
]);
325 /* compatibility: if the mark value is non-zero all bits
326 * are compared unless a mask is explicitly specified.
328 rule
->mark_mask
= 0xFFFFFFFF;
332 rule
->mark_mask
= nla_get_u32(tb
[FRA_FWMASK
]);
334 rule
->action
= frh
->action
;
335 rule
->flags
= frh
->flags
;
336 rule
->table
= frh_get_table(frh
, tb
);
338 if (!tb
[FRA_PRIORITY
] && ops
->default_pref
)
339 rule
->pref
= ops
->default_pref(ops
);
343 if (rule
->action
!= FR_ACT_GOTO
)
346 rule
->target
= nla_get_u32(tb
[FRA_GOTO
]);
347 /* Backward jumps are prohibited to avoid endless loops */
348 if (rule
->target
<= rule
->pref
)
351 list_for_each_entry(r
, &ops
->rules_list
, list
) {
352 if (r
->pref
== rule
->target
) {
353 RCU_INIT_POINTER(rule
->ctarget
, r
);
358 if (rcu_dereference_protected(rule
->ctarget
, 1) == NULL
)
360 } else if (rule
->action
== FR_ACT_GOTO
)
363 err
= ops
->configure(rule
, skb
, frh
, tb
);
367 list_for_each_entry(r
, &ops
->rules_list
, list
) {
368 if (r
->pref
> rule
->pref
)
376 list_add_rcu(&rule
->list
, &last
->list
);
378 list_add_rcu(&rule
->list
, &ops
->rules_list
);
380 if (ops
->unresolved_rules
) {
382 * There are unresolved goto rules in the list, check if
383 * any of them are pointing to this new rule.
385 list_for_each_entry(r
, &ops
->rules_list
, list
) {
386 if (r
->action
== FR_ACT_GOTO
&&
387 r
->target
== rule
->pref
) {
388 BUG_ON(rtnl_dereference(r
->ctarget
) != NULL
);
389 rcu_assign_pointer(r
->ctarget
, rule
);
390 if (--ops
->unresolved_rules
== 0)
396 if (rule
->action
== FR_ACT_GOTO
)
397 ops
->nr_goto_rules
++;
400 ops
->unresolved_rules
++;
402 notify_rule_change(RTM_NEWRULE
, rule
, ops
, nlh
, NETLINK_CB(skb
).pid
);
403 flush_route_cache(ops
);
408 release_net(rule
->fr_net
);
415 static int fib_nl_delrule(struct sk_buff
*skb
, struct nlmsghdr
* nlh
, void *arg
)
417 struct net
*net
= sock_net(skb
->sk
);
418 struct fib_rule_hdr
*frh
= nlmsg_data(nlh
);
419 struct fib_rules_ops
*ops
= NULL
;
420 struct fib_rule
*rule
, *tmp
;
421 struct nlattr
*tb
[FRA_MAX
+1];
424 if (nlh
->nlmsg_len
< nlmsg_msg_size(sizeof(*frh
)))
427 ops
= lookup_rules_ops(net
, frh
->family
);
433 err
= nlmsg_parse(nlh
, sizeof(*frh
), tb
, FRA_MAX
, ops
->policy
);
437 err
= validate_rulemsg(frh
, tb
, ops
);
441 list_for_each_entry(rule
, &ops
->rules_list
, list
) {
442 if (frh
->action
&& (frh
->action
!= rule
->action
))
445 if (frh
->table
&& (frh_get_table(frh
, tb
) != rule
->table
))
448 if (tb
[FRA_PRIORITY
] &&
449 (rule
->pref
!= nla_get_u32(tb
[FRA_PRIORITY
])))
452 if (tb
[FRA_IIFNAME
] &&
453 nla_strcmp(tb
[FRA_IIFNAME
], rule
->iifname
))
456 if (tb
[FRA_OIFNAME
] &&
457 nla_strcmp(tb
[FRA_OIFNAME
], rule
->oifname
))
460 if (tb
[FRA_FWMARK
] &&
461 (rule
->mark
!= nla_get_u32(tb
[FRA_FWMARK
])))
464 if (tb
[FRA_FWMASK
] &&
465 (rule
->mark_mask
!= nla_get_u32(tb
[FRA_FWMASK
])))
468 if (!ops
->compare(rule
, frh
, tb
))
471 if (rule
->flags
& FIB_RULE_PERMANENT
) {
476 list_del_rcu(&rule
->list
);
478 if (rule
->action
== FR_ACT_GOTO
)
479 ops
->nr_goto_rules
--;
482 * Check if this rule is a target to any of them. If so,
483 * disable them. As this operation is eventually very
484 * expensive, it is only performed if goto rules have
485 * actually been added.
487 if (ops
->nr_goto_rules
> 0) {
488 list_for_each_entry(tmp
, &ops
->rules_list
, list
) {
489 if (rtnl_dereference(tmp
->ctarget
) == rule
) {
490 rcu_assign_pointer(tmp
->ctarget
, NULL
);
491 ops
->unresolved_rules
++;
496 notify_rule_change(RTM_DELRULE
, rule
, ops
, nlh
,
497 NETLINK_CB(skb
).pid
);
499 flush_route_cache(ops
);
510 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops
*ops
,
511 struct fib_rule
*rule
)
513 size_t payload
= NLMSG_ALIGN(sizeof(struct fib_rule_hdr
))
514 + nla_total_size(IFNAMSIZ
) /* FRA_IIFNAME */
515 + nla_total_size(IFNAMSIZ
) /* FRA_OIFNAME */
516 + nla_total_size(4) /* FRA_PRIORITY */
517 + nla_total_size(4) /* FRA_TABLE */
518 + nla_total_size(4) /* FRA_FWMARK */
519 + nla_total_size(4); /* FRA_FWMASK */
521 if (ops
->nlmsg_payload
)
522 payload
+= ops
->nlmsg_payload(rule
);
527 static int fib_nl_fill_rule(struct sk_buff
*skb
, struct fib_rule
*rule
,
528 u32 pid
, u32 seq
, int type
, int flags
,
529 struct fib_rules_ops
*ops
)
531 struct nlmsghdr
*nlh
;
532 struct fib_rule_hdr
*frh
;
534 nlh
= nlmsg_put(skb
, pid
, seq
, type
, sizeof(*frh
), flags
);
538 frh
= nlmsg_data(nlh
);
539 frh
->family
= ops
->family
;
540 frh
->table
= rule
->table
;
541 NLA_PUT_U32(skb
, FRA_TABLE
, rule
->table
);
544 frh
->action
= rule
->action
;
545 frh
->flags
= rule
->flags
;
547 if (rule
->action
== FR_ACT_GOTO
&&
548 rcu_dereference_raw(rule
->ctarget
) == NULL
)
549 frh
->flags
|= FIB_RULE_UNRESOLVED
;
551 if (rule
->iifname
[0]) {
552 NLA_PUT_STRING(skb
, FRA_IIFNAME
, rule
->iifname
);
554 if (rule
->iifindex
== -1)
555 frh
->flags
|= FIB_RULE_IIF_DETACHED
;
558 if (rule
->oifname
[0]) {
559 NLA_PUT_STRING(skb
, FRA_OIFNAME
, rule
->oifname
);
561 if (rule
->oifindex
== -1)
562 frh
->flags
|= FIB_RULE_OIF_DETACHED
;
566 NLA_PUT_U32(skb
, FRA_PRIORITY
, rule
->pref
);
569 NLA_PUT_U32(skb
, FRA_FWMARK
, rule
->mark
);
571 if (rule
->mark_mask
|| rule
->mark
)
572 NLA_PUT_U32(skb
, FRA_FWMASK
, rule
->mark_mask
);
575 NLA_PUT_U32(skb
, FRA_GOTO
, rule
->target
);
577 if (ops
->fill(rule
, skb
, frh
) < 0)
578 goto nla_put_failure
;
580 return nlmsg_end(skb
, nlh
);
583 nlmsg_cancel(skb
, nlh
);
587 static int dump_rules(struct sk_buff
*skb
, struct netlink_callback
*cb
,
588 struct fib_rules_ops
*ops
)
591 struct fib_rule
*rule
;
594 list_for_each_entry_rcu(rule
, &ops
->rules_list
, list
) {
595 if (idx
< cb
->args
[1])
598 if (fib_nl_fill_rule(skb
, rule
, NETLINK_CB(cb
->skb
).pid
,
599 cb
->nlh
->nlmsg_seq
, RTM_NEWRULE
,
600 NLM_F_MULTI
, ops
) < 0)
612 static int fib_nl_dumprule(struct sk_buff
*skb
, struct netlink_callback
*cb
)
614 struct net
*net
= sock_net(skb
->sk
);
615 struct fib_rules_ops
*ops
;
618 family
= rtnl_msg_family(cb
->nlh
);
619 if (family
!= AF_UNSPEC
) {
620 /* Protocol specific dump request */
621 ops
= lookup_rules_ops(net
, family
);
623 return -EAFNOSUPPORT
;
625 return dump_rules(skb
, cb
, ops
);
629 list_for_each_entry_rcu(ops
, &net
->rules_ops
, list
) {
630 if (idx
< cb
->args
[0] || !try_module_get(ops
->owner
))
633 if (dump_rules(skb
, cb
, ops
) < 0)
646 static void notify_rule_change(int event
, struct fib_rule
*rule
,
647 struct fib_rules_ops
*ops
, struct nlmsghdr
*nlh
,
655 skb
= nlmsg_new(fib_rule_nlmsg_size(ops
, rule
), GFP_KERNEL
);
659 err
= fib_nl_fill_rule(skb
, rule
, pid
, nlh
->nlmsg_seq
, event
, 0, ops
);
661 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
662 WARN_ON(err
== -EMSGSIZE
);
667 rtnl_notify(skb
, net
, pid
, ops
->nlgroup
, nlh
, GFP_KERNEL
);
671 rtnl_set_sk_err(net
, ops
->nlgroup
, err
);
674 static void attach_rules(struct list_head
*rules
, struct net_device
*dev
)
676 struct fib_rule
*rule
;
678 list_for_each_entry(rule
, rules
, list
) {
679 if (rule
->iifindex
== -1 &&
680 strcmp(dev
->name
, rule
->iifname
) == 0)
681 rule
->iifindex
= dev
->ifindex
;
682 if (rule
->oifindex
== -1 &&
683 strcmp(dev
->name
, rule
->oifname
) == 0)
684 rule
->oifindex
= dev
->ifindex
;
688 static void detach_rules(struct list_head
*rules
, struct net_device
*dev
)
690 struct fib_rule
*rule
;
692 list_for_each_entry(rule
, rules
, list
) {
693 if (rule
->iifindex
== dev
->ifindex
)
695 if (rule
->oifindex
== dev
->ifindex
)
701 static int fib_rules_event(struct notifier_block
*this, unsigned long event
,
704 struct net_device
*dev
= ptr
;
705 struct net
*net
= dev_net(dev
);
706 struct fib_rules_ops
*ops
;
711 case NETDEV_REGISTER
:
712 list_for_each_entry(ops
, &net
->rules_ops
, list
)
713 attach_rules(&ops
->rules_list
, dev
);
716 case NETDEV_UNREGISTER
:
717 list_for_each_entry(ops
, &net
->rules_ops
, list
)
718 detach_rules(&ops
->rules_list
, dev
);
725 static struct notifier_block fib_rules_notifier
= {
726 .notifier_call
= fib_rules_event
,
729 static int __net_init
fib_rules_net_init(struct net
*net
)
731 INIT_LIST_HEAD(&net
->rules_ops
);
732 spin_lock_init(&net
->rules_mod_lock
);
736 static struct pernet_operations fib_rules_net_ops
= {
737 .init
= fib_rules_net_init
,
740 static int __init
fib_rules_init(void)
743 rtnl_register(PF_UNSPEC
, RTM_NEWRULE
, fib_nl_newrule
, NULL
);
744 rtnl_register(PF_UNSPEC
, RTM_DELRULE
, fib_nl_delrule
, NULL
);
745 rtnl_register(PF_UNSPEC
, RTM_GETRULE
, NULL
, fib_nl_dumprule
);
747 err
= register_pernet_subsys(&fib_rules_net_ops
);
751 err
= register_netdevice_notifier(&fib_rules_notifier
);
753 goto fail_unregister
;
758 unregister_pernet_subsys(&fib_rules_net_ops
);
760 rtnl_unregister(PF_UNSPEC
, RTM_NEWRULE
);
761 rtnl_unregister(PF_UNSPEC
, RTM_DELRULE
);
762 rtnl_unregister(PF_UNSPEC
, RTM_GETRULE
);
766 subsys_initcall(fib_rules_init
);