1 /* Connection state tracking for netfilter. This is separated from,
2 but required by, the NAT layer; it can also be used by an iptables
5 /* (C) 1999-2001 Paul `Rusty' Russell
6 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
7 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/types.h>
15 #include <linux/netfilter.h>
16 #include <linux/module.h>
17 #include <linux/skbuff.h>
18 #include <linux/proc_fs.h>
19 #include <linux/vmalloc.h>
20 #include <linux/stddef.h>
21 #include <linux/slab.h>
22 #include <linux/random.h>
23 #include <linux/jhash.h>
24 #include <linux/err.h>
25 #include <linux/percpu.h>
26 #include <linux/moduleparam.h>
27 #include <linux/notifier.h>
28 #include <linux/kernel.h>
29 #include <linux/netdevice.h>
30 #include <linux/socket.h>
33 #include <net/netfilter/nf_conntrack.h>
34 #include <net/netfilter/nf_conntrack_l3proto.h>
35 #include <net/netfilter/nf_conntrack_l4proto.h>
36 #include <net/netfilter/nf_conntrack_expect.h>
37 #include <net/netfilter/nf_conntrack_helper.h>
38 #include <net/netfilter/nf_conntrack_core.h>
39 #include <net/netfilter/nf_conntrack_extend.h>
41 #define NF_CONNTRACK_VERSION "0.5.0"
46 #define DEBUGP(format, args...)
49 DEFINE_RWLOCK(nf_conntrack_lock
);
50 EXPORT_SYMBOL_GPL(nf_conntrack_lock
);
52 /* nf_conntrack_standalone needs this */
53 atomic_t nf_conntrack_count
= ATOMIC_INIT(0);
54 EXPORT_SYMBOL_GPL(nf_conntrack_count
);
56 void (*nf_conntrack_destroyed
)(struct nf_conn
*conntrack
);
57 EXPORT_SYMBOL_GPL(nf_conntrack_destroyed
);
59 unsigned int nf_conntrack_htable_size __read_mostly
;
60 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size
);
62 int nf_conntrack_max __read_mostly
;
63 EXPORT_SYMBOL_GPL(nf_conntrack_max
);
65 struct list_head
*nf_conntrack_hash __read_mostly
;
66 EXPORT_SYMBOL_GPL(nf_conntrack_hash
);
68 struct nf_conn nf_conntrack_untracked __read_mostly
;
69 EXPORT_SYMBOL_GPL(nf_conntrack_untracked
);
71 unsigned int nf_ct_log_invalid __read_mostly
;
72 LIST_HEAD(unconfirmed
);
73 static int nf_conntrack_vmalloc __read_mostly
;
75 static unsigned int nf_conntrack_next_id
;
77 DEFINE_PER_CPU(struct ip_conntrack_stat
, nf_conntrack_stat
);
78 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat
);
81 * This scheme offers various size of "struct nf_conn" dependent on
82 * features(helper, nat, ...)
85 #define NF_CT_FEATURES_NAMELEN 256
87 /* name of slab cache. printed in /proc/slabinfo */
90 /* size of slab cache */
93 /* slab cache pointer */
94 struct kmem_cache
*cachep
;
96 /* allocated slab cache + modules which uses this slab cache */
99 } nf_ct_cache
[NF_CT_F_NUM
];
101 /* protect members of nf_ct_cache except of "use" */
102 DEFINE_RWLOCK(nf_ct_cache_lock
);
104 /* This avoids calling kmem_cache_create() with same name simultaneously */
105 static DEFINE_MUTEX(nf_ct_cache_mutex
);
107 static int nf_conntrack_hash_rnd_initted
;
108 static unsigned int nf_conntrack_hash_rnd
;
110 static u_int32_t
__hash_conntrack(const struct nf_conntrack_tuple
*tuple
,
111 unsigned int size
, unsigned int rnd
)
115 a
= jhash2(tuple
->src
.u3
.all
, ARRAY_SIZE(tuple
->src
.u3
.all
),
116 (tuple
->src
.l3num
<< 16) | tuple
->dst
.protonum
);
117 b
= jhash2(tuple
->dst
.u3
.all
, ARRAY_SIZE(tuple
->dst
.u3
.all
),
118 (tuple
->src
.u
.all
<< 16) | tuple
->dst
.u
.all
);
120 return jhash_2words(a
, b
, rnd
) % size
;
123 static inline u_int32_t
hash_conntrack(const struct nf_conntrack_tuple
*tuple
)
125 return __hash_conntrack(tuple
, nf_conntrack_htable_size
,
126 nf_conntrack_hash_rnd
);
129 int nf_conntrack_register_cache(u_int32_t features
, const char *name
,
134 struct kmem_cache
*cachep
;
136 DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
137 features
, name
, size
);
139 if (features
< NF_CT_F_BASIC
|| features
>= NF_CT_F_NUM
) {
140 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
145 mutex_lock(&nf_ct_cache_mutex
);
147 write_lock_bh(&nf_ct_cache_lock
);
148 /* e.g: multiple helpers are loaded */
149 if (nf_ct_cache
[features
].use
> 0) {
150 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
151 if ((!strncmp(nf_ct_cache
[features
].name
, name
,
152 NF_CT_FEATURES_NAMELEN
))
153 && nf_ct_cache
[features
].size
== size
) {
154 DEBUGP("nf_conntrack_register_cache: reusing.\n");
155 nf_ct_cache
[features
].use
++;
160 write_unlock_bh(&nf_ct_cache_lock
);
161 mutex_unlock(&nf_ct_cache_mutex
);
164 write_unlock_bh(&nf_ct_cache_lock
);
167 * The memory space for name of slab cache must be alive until
168 * cache is destroyed.
170 cache_name
= kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN
, GFP_ATOMIC
);
171 if (cache_name
== NULL
) {
172 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
177 if (strlcpy(cache_name
, name
, NF_CT_FEATURES_NAMELEN
)
178 >= NF_CT_FEATURES_NAMELEN
) {
179 printk("nf_conntrack_register_cache: name too long\n");
184 cachep
= kmem_cache_create(cache_name
, size
, 0, 0,
187 printk("nf_conntrack_register_cache: Can't create slab cache "
188 "for the features = 0x%x\n", features
);
193 write_lock_bh(&nf_ct_cache_lock
);
194 nf_ct_cache
[features
].use
= 1;
195 nf_ct_cache
[features
].size
= size
;
196 nf_ct_cache
[features
].cachep
= cachep
;
197 nf_ct_cache
[features
].name
= cache_name
;
198 write_unlock_bh(&nf_ct_cache_lock
);
205 mutex_unlock(&nf_ct_cache_mutex
);
208 EXPORT_SYMBOL_GPL(nf_conntrack_register_cache
);
210 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
211 void nf_conntrack_unregister_cache(u_int32_t features
)
213 struct kmem_cache
*cachep
;
217 * This assures that kmem_cache_create() isn't called before destroying
220 DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features
);
221 mutex_lock(&nf_ct_cache_mutex
);
223 write_lock_bh(&nf_ct_cache_lock
);
224 if (--nf_ct_cache
[features
].use
> 0) {
225 write_unlock_bh(&nf_ct_cache_lock
);
226 mutex_unlock(&nf_ct_cache_mutex
);
229 cachep
= nf_ct_cache
[features
].cachep
;
230 name
= nf_ct_cache
[features
].name
;
231 nf_ct_cache
[features
].cachep
= NULL
;
232 nf_ct_cache
[features
].name
= NULL
;
233 nf_ct_cache
[features
].size
= 0;
234 write_unlock_bh(&nf_ct_cache_lock
);
238 kmem_cache_destroy(cachep
);
241 mutex_unlock(&nf_ct_cache_mutex
);
243 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_cache
);
246 nf_ct_get_tuple(const struct sk_buff
*skb
,
248 unsigned int dataoff
,
251 struct nf_conntrack_tuple
*tuple
,
252 const struct nf_conntrack_l3proto
*l3proto
,
253 const struct nf_conntrack_l4proto
*l4proto
)
255 NF_CT_TUPLE_U_BLANK(tuple
);
257 tuple
->src
.l3num
= l3num
;
258 if (l3proto
->pkt_to_tuple(skb
, nhoff
, tuple
) == 0)
261 tuple
->dst
.protonum
= protonum
;
262 tuple
->dst
.dir
= IP_CT_DIR_ORIGINAL
;
264 return l4proto
->pkt_to_tuple(skb
, dataoff
, tuple
);
266 EXPORT_SYMBOL_GPL(nf_ct_get_tuple
);
269 nf_ct_invert_tuple(struct nf_conntrack_tuple
*inverse
,
270 const struct nf_conntrack_tuple
*orig
,
271 const struct nf_conntrack_l3proto
*l3proto
,
272 const struct nf_conntrack_l4proto
*l4proto
)
274 NF_CT_TUPLE_U_BLANK(inverse
);
276 inverse
->src
.l3num
= orig
->src
.l3num
;
277 if (l3proto
->invert_tuple(inverse
, orig
) == 0)
280 inverse
->dst
.dir
= !orig
->dst
.dir
;
282 inverse
->dst
.protonum
= orig
->dst
.protonum
;
283 return l4proto
->invert_tuple(inverse
, orig
);
285 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple
);
288 clean_from_lists(struct nf_conn
*ct
)
290 DEBUGP("clean_from_lists(%p)\n", ct
);
291 list_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
);
292 list_del(&ct
->tuplehash
[IP_CT_DIR_REPLY
].list
);
294 /* Destroy all pending expectations */
295 nf_ct_remove_expectations(ct
);
299 destroy_conntrack(struct nf_conntrack
*nfct
)
301 struct nf_conn
*ct
= (struct nf_conn
*)nfct
;
302 struct nf_conntrack_l4proto
*l4proto
;
303 typeof(nf_conntrack_destroyed
) destroyed
;
305 DEBUGP("destroy_conntrack(%p)\n", ct
);
306 NF_CT_ASSERT(atomic_read(&nfct
->use
) == 0);
307 NF_CT_ASSERT(!timer_pending(&ct
->timeout
));
309 nf_conntrack_event(IPCT_DESTROY
, ct
);
310 set_bit(IPS_DYING_BIT
, &ct
->status
);
312 /* To make sure we don't get any weird locking issues here:
313 * destroy_conntrack() MUST NOT be called with a write lock
314 * to nf_conntrack_lock!!! -HW */
316 l4proto
= __nf_ct_l4proto_find(ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.src
.l3num
,
317 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.protonum
);
318 if (l4proto
&& l4proto
->destroy
)
319 l4proto
->destroy(ct
);
321 nf_ct_ext_destroy(ct
);
323 destroyed
= rcu_dereference(nf_conntrack_destroyed
);
329 write_lock_bh(&nf_conntrack_lock
);
330 /* Expectations will have been removed in clean_from_lists,
331 * except TFTP can create an expectation on the first packet,
332 * before connection is in the list, so we need to clean here,
334 nf_ct_remove_expectations(ct
);
336 /* We overload first tuple to link into unconfirmed list. */
337 if (!nf_ct_is_confirmed(ct
)) {
338 BUG_ON(list_empty(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
));
339 list_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
);
342 NF_CT_STAT_INC(delete);
343 write_unlock_bh(&nf_conntrack_lock
);
346 nf_ct_put(ct
->master
);
348 DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct
);
349 nf_conntrack_free(ct
);
352 static void death_by_timeout(unsigned long ul_conntrack
)
354 struct nf_conn
*ct
= (void *)ul_conntrack
;
355 struct nf_conn_help
*help
= nfct_help(ct
);
356 struct nf_conntrack_helper
*helper
;
360 helper
= rcu_dereference(help
->helper
);
361 if (helper
&& helper
->destroy
)
366 write_lock_bh(&nf_conntrack_lock
);
367 /* Inside lock so preempt is disabled on module removal path.
368 * Otherwise we can get spurious warnings. */
369 NF_CT_STAT_INC(delete_list
);
370 clean_from_lists(ct
);
371 write_unlock_bh(&nf_conntrack_lock
);
375 struct nf_conntrack_tuple_hash
*
376 __nf_conntrack_find(const struct nf_conntrack_tuple
*tuple
,
377 const struct nf_conn
*ignored_conntrack
)
379 struct nf_conntrack_tuple_hash
*h
;
380 unsigned int hash
= hash_conntrack(tuple
);
382 list_for_each_entry(h
, &nf_conntrack_hash
[hash
], list
) {
383 if (nf_ct_tuplehash_to_ctrack(h
) != ignored_conntrack
&&
384 nf_ct_tuple_equal(tuple
, &h
->tuple
)) {
385 NF_CT_STAT_INC(found
);
388 NF_CT_STAT_INC(searched
);
393 EXPORT_SYMBOL_GPL(__nf_conntrack_find
);
395 /* Find a connection corresponding to a tuple. */
396 struct nf_conntrack_tuple_hash
*
397 nf_conntrack_find_get(const struct nf_conntrack_tuple
*tuple
,
398 const struct nf_conn
*ignored_conntrack
)
400 struct nf_conntrack_tuple_hash
*h
;
402 read_lock_bh(&nf_conntrack_lock
);
403 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
405 atomic_inc(&nf_ct_tuplehash_to_ctrack(h
)->ct_general
.use
);
406 read_unlock_bh(&nf_conntrack_lock
);
410 EXPORT_SYMBOL_GPL(nf_conntrack_find_get
);
412 static void __nf_conntrack_hash_insert(struct nf_conn
*ct
,
414 unsigned int repl_hash
)
416 ct
->id
= ++nf_conntrack_next_id
;
417 list_add(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
,
418 &nf_conntrack_hash
[hash
]);
419 list_add(&ct
->tuplehash
[IP_CT_DIR_REPLY
].list
,
420 &nf_conntrack_hash
[repl_hash
]);
423 void nf_conntrack_hash_insert(struct nf_conn
*ct
)
425 unsigned int hash
, repl_hash
;
427 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
428 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
430 write_lock_bh(&nf_conntrack_lock
);
431 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
432 write_unlock_bh(&nf_conntrack_lock
);
434 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert
);
436 /* Confirm a connection given skb; places it in hash table */
438 __nf_conntrack_confirm(struct sk_buff
**pskb
)
440 unsigned int hash
, repl_hash
;
441 struct nf_conntrack_tuple_hash
*h
;
443 struct nf_conn_help
*help
;
444 enum ip_conntrack_info ctinfo
;
446 ct
= nf_ct_get(*pskb
, &ctinfo
);
448 /* ipt_REJECT uses nf_conntrack_attach to attach related
449 ICMP/TCP RST packets in other direction. Actual packet
450 which created connection will be IP_CT_NEW or for an
451 expected connection, IP_CT_RELATED. */
452 if (CTINFO2DIR(ctinfo
) != IP_CT_DIR_ORIGINAL
)
455 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
456 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
458 /* We're not in hash table, and we refuse to set up related
459 connections for unconfirmed conns. But packet copies and
460 REJECT will give spurious warnings here. */
461 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
463 /* No external references means noone else could have
465 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
466 DEBUGP("Confirming conntrack %p\n", ct
);
468 write_lock_bh(&nf_conntrack_lock
);
470 /* See if there's one in the list already, including reverse:
471 NAT could have grabbed it without realizing, since we're
472 not in the hash. If there is, we lost race. */
473 list_for_each_entry(h
, &nf_conntrack_hash
[hash
], list
)
474 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
477 list_for_each_entry(h
, &nf_conntrack_hash
[repl_hash
], list
)
478 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
482 /* Remove from unconfirmed list */
483 list_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
);
485 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
486 /* Timer relative to confirmation time, not original
487 setting time, otherwise we'd get timer wrap in
488 weird delay cases. */
489 ct
->timeout
.expires
+= jiffies
;
490 add_timer(&ct
->timeout
);
491 atomic_inc(&ct
->ct_general
.use
);
492 set_bit(IPS_CONFIRMED_BIT
, &ct
->status
);
493 NF_CT_STAT_INC(insert
);
494 write_unlock_bh(&nf_conntrack_lock
);
495 help
= nfct_help(ct
);
496 if (help
&& help
->helper
)
497 nf_conntrack_event_cache(IPCT_HELPER
, *pskb
);
498 #ifdef CONFIG_NF_NAT_NEEDED
499 if (test_bit(IPS_SRC_NAT_DONE_BIT
, &ct
->status
) ||
500 test_bit(IPS_DST_NAT_DONE_BIT
, &ct
->status
))
501 nf_conntrack_event_cache(IPCT_NATINFO
, *pskb
);
503 nf_conntrack_event_cache(master_ct(ct
) ?
504 IPCT_RELATED
: IPCT_NEW
, *pskb
);
508 NF_CT_STAT_INC(insert_failed
);
509 write_unlock_bh(&nf_conntrack_lock
);
512 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm
);
514 /* Returns true if a connection correspondings to the tuple (required
517 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple
*tuple
,
518 const struct nf_conn
*ignored_conntrack
)
520 struct nf_conntrack_tuple_hash
*h
;
522 read_lock_bh(&nf_conntrack_lock
);
523 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
524 read_unlock_bh(&nf_conntrack_lock
);
528 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken
);
530 /* There's a small race here where we may free a just-assured
531 connection. Too bad: we're in trouble anyway. */
532 static int early_drop(struct list_head
*chain
)
534 /* Traverse backwards: gives us oldest, which is roughly LRU */
535 struct nf_conntrack_tuple_hash
*h
;
536 struct nf_conn
*ct
= NULL
, *tmp
;
539 read_lock_bh(&nf_conntrack_lock
);
540 list_for_each_entry_reverse(h
, chain
, list
) {
541 tmp
= nf_ct_tuplehash_to_ctrack(h
);
542 if (!test_bit(IPS_ASSURED_BIT
, &tmp
->status
)) {
544 atomic_inc(&ct
->ct_general
.use
);
548 read_unlock_bh(&nf_conntrack_lock
);
553 if (del_timer(&ct
->timeout
)) {
554 death_by_timeout((unsigned long)ct
);
556 NF_CT_STAT_INC_ATOMIC(early_drop
);
562 static struct nf_conn
*
563 __nf_conntrack_alloc(const struct nf_conntrack_tuple
*orig
,
564 const struct nf_conntrack_tuple
*repl
,
565 const struct nf_conntrack_l3proto
*l3proto
,
568 struct nf_conn
*conntrack
= NULL
;
569 struct nf_conntrack_helper
*helper
;
571 if (unlikely(!nf_conntrack_hash_rnd_initted
)) {
572 get_random_bytes(&nf_conntrack_hash_rnd
, 4);
573 nf_conntrack_hash_rnd_initted
= 1;
576 /* We don't want any race condition at early drop stage */
577 atomic_inc(&nf_conntrack_count
);
580 && atomic_read(&nf_conntrack_count
) > nf_conntrack_max
) {
581 unsigned int hash
= hash_conntrack(orig
);
582 /* Try dropping from this hash chain. */
583 if (!early_drop(&nf_conntrack_hash
[hash
])) {
584 atomic_dec(&nf_conntrack_count
);
587 "nf_conntrack: table full, dropping"
589 return ERR_PTR(-ENOMEM
);
593 /* find features needed by this conntrack. */
594 features
|= l3proto
->get_features(orig
);
596 /* FIXME: protect helper list per RCU */
597 read_lock_bh(&nf_conntrack_lock
);
598 helper
= __nf_ct_helper_find(repl
);
599 /* NAT might want to assign a helper later */
600 if (helper
|| features
& NF_CT_F_NAT
)
601 features
|= NF_CT_F_HELP
;
602 read_unlock_bh(&nf_conntrack_lock
);
604 DEBUGP("nf_conntrack_alloc: features=0x%x\n", features
);
606 read_lock_bh(&nf_ct_cache_lock
);
608 if (unlikely(!nf_ct_cache
[features
].use
)) {
609 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
614 conntrack
= kmem_cache_alloc(nf_ct_cache
[features
].cachep
, GFP_ATOMIC
);
615 if (conntrack
== NULL
) {
616 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
620 memset(conntrack
, 0, nf_ct_cache
[features
].size
);
621 conntrack
->features
= features
;
622 atomic_set(&conntrack
->ct_general
.use
, 1);
623 conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
= *orig
;
624 conntrack
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *repl
;
625 /* Don't set timer yet: wait for confirmation */
626 setup_timer(&conntrack
->timeout
, death_by_timeout
,
627 (unsigned long)conntrack
);
628 read_unlock_bh(&nf_ct_cache_lock
);
632 read_unlock_bh(&nf_ct_cache_lock
);
633 atomic_dec(&nf_conntrack_count
);
637 struct nf_conn
*nf_conntrack_alloc(const struct nf_conntrack_tuple
*orig
,
638 const struct nf_conntrack_tuple
*repl
)
640 struct nf_conntrack_l3proto
*l3proto
;
644 l3proto
= __nf_ct_l3proto_find(orig
->src
.l3num
);
645 ct
= __nf_conntrack_alloc(orig
, repl
, l3proto
, 0);
650 EXPORT_SYMBOL_GPL(nf_conntrack_alloc
);
652 void nf_conntrack_free(struct nf_conn
*conntrack
)
654 u_int32_t features
= conntrack
->features
;
655 NF_CT_ASSERT(features
>= NF_CT_F_BASIC
&& features
< NF_CT_F_NUM
);
656 nf_ct_ext_free(conntrack
);
657 DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features
,
659 kmem_cache_free(nf_ct_cache
[features
].cachep
, conntrack
);
660 atomic_dec(&nf_conntrack_count
);
662 EXPORT_SYMBOL_GPL(nf_conntrack_free
);
664 /* Allocate a new conntrack: we return -ENOMEM if classification
665 failed due to stress. Otherwise it really is unclassifiable. */
666 static struct nf_conntrack_tuple_hash
*
667 init_conntrack(const struct nf_conntrack_tuple
*tuple
,
668 struct nf_conntrack_l3proto
*l3proto
,
669 struct nf_conntrack_l4proto
*l4proto
,
671 unsigned int dataoff
)
673 struct nf_conn
*conntrack
;
674 struct nf_conn_help
*help
;
675 struct nf_conntrack_tuple repl_tuple
;
676 struct nf_conntrack_expect
*exp
;
677 u_int32_t features
= 0;
679 if (!nf_ct_invert_tuple(&repl_tuple
, tuple
, l3proto
, l4proto
)) {
680 DEBUGP("Can't invert tuple.\n");
684 read_lock_bh(&nf_conntrack_lock
);
685 exp
= __nf_conntrack_expect_find(tuple
);
686 if (exp
&& exp
->helper
)
687 features
= NF_CT_F_HELP
;
688 read_unlock_bh(&nf_conntrack_lock
);
690 conntrack
= __nf_conntrack_alloc(tuple
, &repl_tuple
, l3proto
, features
);
691 if (conntrack
== NULL
|| IS_ERR(conntrack
)) {
692 DEBUGP("Can't allocate conntrack.\n");
693 return (struct nf_conntrack_tuple_hash
*)conntrack
;
696 if (!l4proto
->new(conntrack
, skb
, dataoff
)) {
697 nf_conntrack_free(conntrack
);
698 DEBUGP("init conntrack: can't track with proto module\n");
702 write_lock_bh(&nf_conntrack_lock
);
703 exp
= find_expectation(tuple
);
705 help
= nfct_help(conntrack
);
707 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
709 /* Welcome, Mr. Bond. We've been expecting you... */
710 __set_bit(IPS_EXPECTED_BIT
, &conntrack
->status
);
711 conntrack
->master
= exp
->master
;
713 rcu_assign_pointer(help
->helper
, exp
->helper
);
714 #ifdef CONFIG_NF_CONNTRACK_MARK
715 conntrack
->mark
= exp
->master
->mark
;
717 #ifdef CONFIG_NF_CONNTRACK_SECMARK
718 conntrack
->secmark
= exp
->master
->secmark
;
720 nf_conntrack_get(&conntrack
->master
->ct_general
);
721 NF_CT_STAT_INC(expect_new
);
724 /* not in hash table yet, so not strictly necessary */
725 rcu_assign_pointer(help
->helper
,
726 __nf_ct_helper_find(&repl_tuple
));
731 /* Overload tuple linked list to put us in unconfirmed list. */
732 list_add(&conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
, &unconfirmed
);
734 write_unlock_bh(&nf_conntrack_lock
);
738 exp
->expectfn(conntrack
, exp
);
739 nf_conntrack_expect_put(exp
);
742 return &conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
];
745 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
746 static inline struct nf_conn
*
747 resolve_normal_ct(struct sk_buff
*skb
,
748 unsigned int dataoff
,
751 struct nf_conntrack_l3proto
*l3proto
,
752 struct nf_conntrack_l4proto
*l4proto
,
754 enum ip_conntrack_info
*ctinfo
)
756 struct nf_conntrack_tuple tuple
;
757 struct nf_conntrack_tuple_hash
*h
;
760 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
),
761 dataoff
, l3num
, protonum
, &tuple
, l3proto
,
763 DEBUGP("resolve_normal_ct: Can't get tuple\n");
767 /* look for tuple match */
768 h
= nf_conntrack_find_get(&tuple
, NULL
);
770 h
= init_conntrack(&tuple
, l3proto
, l4proto
, skb
, dataoff
);
776 ct
= nf_ct_tuplehash_to_ctrack(h
);
778 /* It exists; we have (non-exclusive) reference. */
779 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
) {
780 *ctinfo
= IP_CT_ESTABLISHED
+ IP_CT_IS_REPLY
;
781 /* Please set reply bit if this packet OK */
784 /* Once we've had two way comms, always ESTABLISHED. */
785 if (test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
786 DEBUGP("nf_conntrack_in: normal packet for %p\n", ct
);
787 *ctinfo
= IP_CT_ESTABLISHED
;
788 } else if (test_bit(IPS_EXPECTED_BIT
, &ct
->status
)) {
789 DEBUGP("nf_conntrack_in: related packet for %p\n", ct
);
790 *ctinfo
= IP_CT_RELATED
;
792 DEBUGP("nf_conntrack_in: new packet for %p\n", ct
);
797 skb
->nfct
= &ct
->ct_general
;
798 skb
->nfctinfo
= *ctinfo
;
803 nf_conntrack_in(int pf
, unsigned int hooknum
, struct sk_buff
**pskb
)
806 enum ip_conntrack_info ctinfo
;
807 struct nf_conntrack_l3proto
*l3proto
;
808 struct nf_conntrack_l4proto
*l4proto
;
809 unsigned int dataoff
;
814 /* Previously seen (loopback or untracked)? Ignore. */
816 NF_CT_STAT_INC_ATOMIC(ignore
);
820 /* rcu_read_lock()ed by nf_hook_slow */
821 l3proto
= __nf_ct_l3proto_find((u_int16_t
)pf
);
823 if ((ret
= l3proto
->prepare(pskb
, hooknum
, &dataoff
, &protonum
)) <= 0) {
824 DEBUGP("not prepared to track yet or error occured\n");
828 l4proto
= __nf_ct_l4proto_find((u_int16_t
)pf
, protonum
);
830 /* It may be an special packet, error, unclean...
831 * inverse of the return code tells to the netfilter
832 * core what to do with the packet. */
833 if (l4proto
->error
!= NULL
&&
834 (ret
= l4proto
->error(*pskb
, dataoff
, &ctinfo
, pf
, hooknum
)) <= 0) {
835 NF_CT_STAT_INC_ATOMIC(error
);
836 NF_CT_STAT_INC_ATOMIC(invalid
);
840 ct
= resolve_normal_ct(*pskb
, dataoff
, pf
, protonum
, l3proto
, l4proto
,
841 &set_reply
, &ctinfo
);
843 /* Not valid part of a connection */
844 NF_CT_STAT_INC_ATOMIC(invalid
);
849 /* Too stressed to deal. */
850 NF_CT_STAT_INC_ATOMIC(drop
);
854 NF_CT_ASSERT((*pskb
)->nfct
);
856 ret
= l4proto
->packet(ct
, *pskb
, dataoff
, ctinfo
, pf
, hooknum
);
858 /* Invalid: inverse of the return code tells
859 * the netfilter core what to do */
860 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
861 nf_conntrack_put((*pskb
)->nfct
);
862 (*pskb
)->nfct
= NULL
;
863 NF_CT_STAT_INC_ATOMIC(invalid
);
867 if (set_reply
&& !test_and_set_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
))
868 nf_conntrack_event_cache(IPCT_STATUS
, *pskb
);
872 EXPORT_SYMBOL_GPL(nf_conntrack_in
);
874 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple
*inverse
,
875 const struct nf_conntrack_tuple
*orig
)
880 ret
= nf_ct_invert_tuple(inverse
, orig
,
881 __nf_ct_l3proto_find(orig
->src
.l3num
),
882 __nf_ct_l4proto_find(orig
->src
.l3num
,
883 orig
->dst
.protonum
));
887 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr
);
889 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
890 implicitly racy: see __nf_conntrack_confirm */
891 void nf_conntrack_alter_reply(struct nf_conn
*ct
,
892 const struct nf_conntrack_tuple
*newreply
)
894 struct nf_conn_help
*help
= nfct_help(ct
);
896 write_lock_bh(&nf_conntrack_lock
);
897 /* Should be unconfirmed, so not in hash table yet */
898 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
900 DEBUGP("Altering reply tuple of %p to ", ct
);
901 NF_CT_DUMP_TUPLE(newreply
);
903 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *newreply
;
904 if (!ct
->master
&& help
&& help
->expecting
== 0) {
905 struct nf_conntrack_helper
*helper
;
906 helper
= __nf_ct_helper_find(newreply
);
908 memset(&help
->help
, 0, sizeof(help
->help
));
909 /* not in hash table yet, so not strictly necessary */
910 rcu_assign_pointer(help
->helper
, helper
);
912 write_unlock_bh(&nf_conntrack_lock
);
914 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply
);
916 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
917 void __nf_ct_refresh_acct(struct nf_conn
*ct
,
918 enum ip_conntrack_info ctinfo
,
919 const struct sk_buff
*skb
,
920 unsigned long extra_jiffies
,
925 NF_CT_ASSERT(ct
->timeout
.data
== (unsigned long)ct
);
928 write_lock_bh(&nf_conntrack_lock
);
930 /* Only update if this is not a fixed timeout */
931 if (test_bit(IPS_FIXED_TIMEOUT_BIT
, &ct
->status
)) {
932 write_unlock_bh(&nf_conntrack_lock
);
936 /* If not in hash table, timer will not be active yet */
937 if (!nf_ct_is_confirmed(ct
)) {
938 ct
->timeout
.expires
= extra_jiffies
;
939 event
= IPCT_REFRESH
;
941 unsigned long newtime
= jiffies
+ extra_jiffies
;
943 /* Only update the timeout if the new timeout is at least
944 HZ jiffies from the old timeout. Need del_timer for race
945 avoidance (may already be dying). */
946 if (newtime
- ct
->timeout
.expires
>= HZ
947 && del_timer(&ct
->timeout
)) {
948 ct
->timeout
.expires
= newtime
;
949 add_timer(&ct
->timeout
);
950 event
= IPCT_REFRESH
;
954 #ifdef CONFIG_NF_CT_ACCT
956 ct
->counters
[CTINFO2DIR(ctinfo
)].packets
++;
957 ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
+=
958 skb
->len
- skb_network_offset(skb
);
960 if ((ct
->counters
[CTINFO2DIR(ctinfo
)].packets
& 0x80000000)
961 || (ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
& 0x80000000))
962 event
|= IPCT_COUNTER_FILLING
;
966 write_unlock_bh(&nf_conntrack_lock
);
968 /* must be unlocked when calling event cache */
970 nf_conntrack_event_cache(event
, skb
);
972 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct
);
974 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
976 #include <linux/netfilter/nfnetlink.h>
977 #include <linux/netfilter/nfnetlink_conntrack.h>
978 #include <linux/mutex.h>
981 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
982 * in ip_conntrack_core, since we don't want the protocols to autoload
983 * or depend on ctnetlink */
984 int nf_ct_port_tuple_to_nfattr(struct sk_buff
*skb
,
985 const struct nf_conntrack_tuple
*tuple
)
987 NFA_PUT(skb
, CTA_PROTO_SRC_PORT
, sizeof(u_int16_t
),
988 &tuple
->src
.u
.tcp
.port
);
989 NFA_PUT(skb
, CTA_PROTO_DST_PORT
, sizeof(u_int16_t
),
990 &tuple
->dst
.u
.tcp
.port
);
996 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr
);
998 static const size_t cta_min_proto
[CTA_PROTO_MAX
] = {
999 [CTA_PROTO_SRC_PORT
-1] = sizeof(u_int16_t
),
1000 [CTA_PROTO_DST_PORT
-1] = sizeof(u_int16_t
)
1003 int nf_ct_port_nfattr_to_tuple(struct nfattr
*tb
[],
1004 struct nf_conntrack_tuple
*t
)
1006 if (!tb
[CTA_PROTO_SRC_PORT
-1] || !tb
[CTA_PROTO_DST_PORT
-1])
1009 if (nfattr_bad_size(tb
, CTA_PROTO_MAX
, cta_min_proto
))
1012 t
->src
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_SRC_PORT
-1]);
1013 t
->dst
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_DST_PORT
-1]);
1017 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple
);
1020 /* Used by ipt_REJECT and ip6t_REJECT. */
1021 void __nf_conntrack_attach(struct sk_buff
*nskb
, struct sk_buff
*skb
)
1024 enum ip_conntrack_info ctinfo
;
1026 /* This ICMP is in reverse direction to the packet which caused it */
1027 ct
= nf_ct_get(skb
, &ctinfo
);
1028 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
)
1029 ctinfo
= IP_CT_RELATED
+ IP_CT_IS_REPLY
;
1031 ctinfo
= IP_CT_RELATED
;
1033 /* Attach to new skbuff, and increment count */
1034 nskb
->nfct
= &ct
->ct_general
;
1035 nskb
->nfctinfo
= ctinfo
;
1036 nf_conntrack_get(nskb
->nfct
);
1038 EXPORT_SYMBOL_GPL(__nf_conntrack_attach
);
1041 do_iter(const struct nf_conntrack_tuple_hash
*i
,
1042 int (*iter
)(struct nf_conn
*i
, void *data
),
1045 return iter(nf_ct_tuplehash_to_ctrack(i
), data
);
1048 /* Bring out ya dead! */
1049 static struct nf_conn
*
1050 get_next_corpse(int (*iter
)(struct nf_conn
*i
, void *data
),
1051 void *data
, unsigned int *bucket
)
1053 struct nf_conntrack_tuple_hash
*h
;
1056 write_lock_bh(&nf_conntrack_lock
);
1057 for (; *bucket
< nf_conntrack_htable_size
; (*bucket
)++) {
1058 list_for_each_entry(h
, &nf_conntrack_hash
[*bucket
], list
) {
1059 ct
= nf_ct_tuplehash_to_ctrack(h
);
1064 list_for_each_entry(h
, &unconfirmed
, list
) {
1065 ct
= nf_ct_tuplehash_to_ctrack(h
);
1067 set_bit(IPS_DYING_BIT
, &ct
->status
);
1069 write_unlock_bh(&nf_conntrack_lock
);
1072 atomic_inc(&ct
->ct_general
.use
);
1073 write_unlock_bh(&nf_conntrack_lock
);
1078 nf_ct_iterate_cleanup(int (*iter
)(struct nf_conn
*i
, void *data
), void *data
)
1081 unsigned int bucket
= 0;
1083 while ((ct
= get_next_corpse(iter
, data
, &bucket
)) != NULL
) {
1084 /* Time to push up daises... */
1085 if (del_timer(&ct
->timeout
))
1086 death_by_timeout((unsigned long)ct
);
1087 /* ... else the timer will get him soon. */
1092 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup
);
1094 static int kill_all(struct nf_conn
*i
, void *data
)
1099 static void free_conntrack_hash(struct list_head
*hash
, int vmalloced
, int size
)
1104 free_pages((unsigned long)hash
,
1105 get_order(sizeof(struct list_head
) * size
));
1108 void nf_conntrack_flush(void)
1110 nf_ct_iterate_cleanup(kill_all
, NULL
);
1112 EXPORT_SYMBOL_GPL(nf_conntrack_flush
);
1114 /* Mishearing the voices in his head, our hero wonders how he's
1115 supposed to kill the mall. */
1116 void nf_conntrack_cleanup(void)
1120 rcu_assign_pointer(ip_ct_attach
, NULL
);
1122 /* This makes sure all current packets have passed through
1123 netfilter framework. Roll on, two-stage module
1127 nf_ct_event_cache_flush();
1129 nf_conntrack_flush();
1130 if (atomic_read(&nf_conntrack_count
) != 0) {
1132 goto i_see_dead_people
;
1134 /* wait until all references to nf_conntrack_untracked are dropped */
1135 while (atomic_read(&nf_conntrack_untracked
.ct_general
.use
) > 1)
1138 rcu_assign_pointer(nf_ct_destroy
, NULL
);
1140 for (i
= 0; i
< NF_CT_F_NUM
; i
++) {
1141 if (nf_ct_cache
[i
].use
== 0)
1144 NF_CT_ASSERT(nf_ct_cache
[i
].use
== 1);
1145 nf_ct_cache
[i
].use
= 1;
1146 nf_conntrack_unregister_cache(i
);
1148 kmem_cache_destroy(nf_conntrack_expect_cachep
);
1149 free_conntrack_hash(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1150 nf_conntrack_htable_size
);
1152 nf_conntrack_proto_fini();
1155 static struct list_head
*alloc_hashtable(int size
, int *vmalloced
)
1157 struct list_head
*hash
;
1161 hash
= (void*)__get_free_pages(GFP_KERNEL
,
1162 get_order(sizeof(struct list_head
)
1166 printk(KERN_WARNING
"nf_conntrack: falling back to vmalloc.\n");
1167 hash
= vmalloc(sizeof(struct list_head
) * size
);
1171 for (i
= 0; i
< size
; i
++)
1172 INIT_LIST_HEAD(&hash
[i
]);
1177 int set_hashsize(const char *val
, struct kernel_param
*kp
)
1179 int i
, bucket
, hashsize
, vmalloced
;
1180 int old_vmalloced
, old_size
;
1182 struct list_head
*hash
, *old_hash
;
1183 struct nf_conntrack_tuple_hash
*h
;
1185 /* On boot, we can set this without any fancy locking. */
1186 if (!nf_conntrack_htable_size
)
1187 return param_set_uint(val
, kp
);
1189 hashsize
= simple_strtol(val
, NULL
, 0);
1193 hash
= alloc_hashtable(hashsize
, &vmalloced
);
1197 /* We have to rehahs for the new table anyway, so we also can
1198 * use a newrandom seed */
1199 get_random_bytes(&rnd
, 4);
1201 write_lock_bh(&nf_conntrack_lock
);
1202 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
1203 while (!list_empty(&nf_conntrack_hash
[i
])) {
1204 h
= list_entry(nf_conntrack_hash
[i
].next
,
1205 struct nf_conntrack_tuple_hash
, list
);
1207 bucket
= __hash_conntrack(&h
->tuple
, hashsize
, rnd
);
1208 list_add_tail(&h
->list
, &hash
[bucket
]);
1211 old_size
= nf_conntrack_htable_size
;
1212 old_vmalloced
= nf_conntrack_vmalloc
;
1213 old_hash
= nf_conntrack_hash
;
1215 nf_conntrack_htable_size
= hashsize
;
1216 nf_conntrack_vmalloc
= vmalloced
;
1217 nf_conntrack_hash
= hash
;
1218 nf_conntrack_hash_rnd
= rnd
;
1219 write_unlock_bh(&nf_conntrack_lock
);
1221 free_conntrack_hash(old_hash
, old_vmalloced
, old_size
);
1225 module_param_call(hashsize
, set_hashsize
, param_get_uint
,
1226 &nf_conntrack_htable_size
, 0600);
1228 int __init
nf_conntrack_init(void)
1232 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1233 * machine has 256 buckets. >= 1GB machines have 8192 buckets. */
1234 if (!nf_conntrack_htable_size
) {
1235 nf_conntrack_htable_size
1236 = (((num_physpages
<< PAGE_SHIFT
) / 16384)
1237 / sizeof(struct list_head
));
1238 if (num_physpages
> (1024 * 1024 * 1024 / PAGE_SIZE
))
1239 nf_conntrack_htable_size
= 8192;
1240 if (nf_conntrack_htable_size
< 16)
1241 nf_conntrack_htable_size
= 16;
1243 nf_conntrack_max
= 8 * nf_conntrack_htable_size
;
1245 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1246 NF_CONNTRACK_VERSION
, nf_conntrack_htable_size
,
1249 nf_conntrack_hash
= alloc_hashtable(nf_conntrack_htable_size
,
1250 &nf_conntrack_vmalloc
);
1251 if (!nf_conntrack_hash
) {
1252 printk(KERN_ERR
"Unable to create nf_conntrack_hash\n");
1256 ret
= nf_conntrack_register_cache(NF_CT_F_BASIC
, "nf_conntrack:basic",
1257 sizeof(struct nf_conn
));
1259 printk(KERN_ERR
"Unable to create nf_conn slab cache\n");
1263 nf_conntrack_expect_cachep
= kmem_cache_create("nf_conntrack_expect",
1264 sizeof(struct nf_conntrack_expect
),
1266 if (!nf_conntrack_expect_cachep
) {
1267 printk(KERN_ERR
"Unable to create nf_expect slab cache\n");
1268 goto err_free_conntrack_slab
;
1271 ret
= nf_conntrack_proto_init();
1273 goto out_free_expect_slab
;
1275 /* For use by REJECT target */
1276 rcu_assign_pointer(ip_ct_attach
, __nf_conntrack_attach
);
1277 rcu_assign_pointer(nf_ct_destroy
, destroy_conntrack
);
1279 /* Set up fake conntrack:
1280 - to never be deleted, not in any hashes */
1281 atomic_set(&nf_conntrack_untracked
.ct_general
.use
, 1);
1282 /* - and look it like as a confirmed connection */
1283 set_bit(IPS_CONFIRMED_BIT
, &nf_conntrack_untracked
.status
);
1287 out_free_expect_slab
:
1288 kmem_cache_destroy(nf_conntrack_expect_cachep
);
1289 err_free_conntrack_slab
:
1290 nf_conntrack_unregister_cache(NF_CT_F_BASIC
);
1292 free_conntrack_hash(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1293 nf_conntrack_htable_size
);