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>
40 #define NF_CONNTRACK_VERSION "0.5.0"
45 #define DEBUGP(format, args...)
48 DEFINE_RWLOCK(nf_conntrack_lock
);
49 EXPORT_SYMBOL_GPL(nf_conntrack_lock
);
51 /* nf_conntrack_standalone needs this */
52 atomic_t nf_conntrack_count
= ATOMIC_INIT(0);
53 EXPORT_SYMBOL_GPL(nf_conntrack_count
);
55 void (*nf_conntrack_destroyed
)(struct nf_conn
*conntrack
);
56 EXPORT_SYMBOL_GPL(nf_conntrack_destroyed
);
58 unsigned int nf_conntrack_htable_size __read_mostly
;
59 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size
);
61 int nf_conntrack_max __read_mostly
;
62 EXPORT_SYMBOL_GPL(nf_conntrack_max
);
64 struct list_head
*nf_conntrack_hash __read_mostly
;
65 EXPORT_SYMBOL_GPL(nf_conntrack_hash
);
67 struct nf_conn nf_conntrack_untracked __read_mostly
;
68 EXPORT_SYMBOL_GPL(nf_conntrack_untracked
);
70 unsigned int nf_ct_log_invalid __read_mostly
;
71 LIST_HEAD(unconfirmed
);
72 static int nf_conntrack_vmalloc __read_mostly
;
74 static unsigned int nf_conntrack_next_id
;
76 DEFINE_PER_CPU(struct ip_conntrack_stat
, nf_conntrack_stat
);
77 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat
);
80 * This scheme offers various size of "struct nf_conn" dependent on
81 * features(helper, nat, ...)
84 #define NF_CT_FEATURES_NAMELEN 256
86 /* name of slab cache. printed in /proc/slabinfo */
89 /* size of slab cache */
92 /* slab cache pointer */
93 struct kmem_cache
*cachep
;
95 /* allocated slab cache + modules which uses this slab cache */
98 } nf_ct_cache
[NF_CT_F_NUM
];
100 /* protect members of nf_ct_cache except of "use" */
101 DEFINE_RWLOCK(nf_ct_cache_lock
);
103 /* This avoids calling kmem_cache_create() with same name simultaneously */
104 static DEFINE_MUTEX(nf_ct_cache_mutex
);
106 static int nf_conntrack_hash_rnd_initted
;
107 static unsigned int nf_conntrack_hash_rnd
;
109 static u_int32_t
__hash_conntrack(const struct nf_conntrack_tuple
*tuple
,
110 unsigned int size
, unsigned int rnd
)
114 a
= jhash2(tuple
->src
.u3
.all
, ARRAY_SIZE(tuple
->src
.u3
.all
),
115 (tuple
->src
.l3num
<< 16) | tuple
->dst
.protonum
);
116 b
= jhash2(tuple
->dst
.u3
.all
, ARRAY_SIZE(tuple
->dst
.u3
.all
),
117 (tuple
->src
.u
.all
<< 16) | tuple
->dst
.u
.all
);
119 return jhash_2words(a
, b
, rnd
) % size
;
122 static inline u_int32_t
hash_conntrack(const struct nf_conntrack_tuple
*tuple
)
124 return __hash_conntrack(tuple
, nf_conntrack_htable_size
,
125 nf_conntrack_hash_rnd
);
128 int nf_conntrack_register_cache(u_int32_t features
, const char *name
,
133 struct kmem_cache
*cachep
;
135 DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
136 features
, name
, size
);
138 if (features
< NF_CT_F_BASIC
|| features
>= NF_CT_F_NUM
) {
139 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
144 mutex_lock(&nf_ct_cache_mutex
);
146 write_lock_bh(&nf_ct_cache_lock
);
147 /* e.g: multiple helpers are loaded */
148 if (nf_ct_cache
[features
].use
> 0) {
149 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
150 if ((!strncmp(nf_ct_cache
[features
].name
, name
,
151 NF_CT_FEATURES_NAMELEN
))
152 && nf_ct_cache
[features
].size
== size
) {
153 DEBUGP("nf_conntrack_register_cache: reusing.\n");
154 nf_ct_cache
[features
].use
++;
159 write_unlock_bh(&nf_ct_cache_lock
);
160 mutex_unlock(&nf_ct_cache_mutex
);
163 write_unlock_bh(&nf_ct_cache_lock
);
166 * The memory space for name of slab cache must be alive until
167 * cache is destroyed.
169 cache_name
= kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN
, GFP_ATOMIC
);
170 if (cache_name
== NULL
) {
171 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
176 if (strlcpy(cache_name
, name
, NF_CT_FEATURES_NAMELEN
)
177 >= NF_CT_FEATURES_NAMELEN
) {
178 printk("nf_conntrack_register_cache: name too long\n");
183 cachep
= kmem_cache_create(cache_name
, size
, 0, 0,
186 printk("nf_conntrack_register_cache: Can't create slab cache "
187 "for the features = 0x%x\n", features
);
192 write_lock_bh(&nf_ct_cache_lock
);
193 nf_ct_cache
[features
].use
= 1;
194 nf_ct_cache
[features
].size
= size
;
195 nf_ct_cache
[features
].cachep
= cachep
;
196 nf_ct_cache
[features
].name
= cache_name
;
197 write_unlock_bh(&nf_ct_cache_lock
);
204 mutex_unlock(&nf_ct_cache_mutex
);
207 EXPORT_SYMBOL_GPL(nf_conntrack_register_cache
);
209 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
210 void nf_conntrack_unregister_cache(u_int32_t features
)
212 struct kmem_cache
*cachep
;
216 * This assures that kmem_cache_create() isn't called before destroying
219 DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features
);
220 mutex_lock(&nf_ct_cache_mutex
);
222 write_lock_bh(&nf_ct_cache_lock
);
223 if (--nf_ct_cache
[features
].use
> 0) {
224 write_unlock_bh(&nf_ct_cache_lock
);
225 mutex_unlock(&nf_ct_cache_mutex
);
228 cachep
= nf_ct_cache
[features
].cachep
;
229 name
= nf_ct_cache
[features
].name
;
230 nf_ct_cache
[features
].cachep
= NULL
;
231 nf_ct_cache
[features
].name
= NULL
;
232 nf_ct_cache
[features
].size
= 0;
233 write_unlock_bh(&nf_ct_cache_lock
);
237 kmem_cache_destroy(cachep
);
240 mutex_unlock(&nf_ct_cache_mutex
);
242 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_cache
);
245 nf_ct_get_tuple(const struct sk_buff
*skb
,
247 unsigned int dataoff
,
250 struct nf_conntrack_tuple
*tuple
,
251 const struct nf_conntrack_l3proto
*l3proto
,
252 const struct nf_conntrack_l4proto
*l4proto
)
254 NF_CT_TUPLE_U_BLANK(tuple
);
256 tuple
->src
.l3num
= l3num
;
257 if (l3proto
->pkt_to_tuple(skb
, nhoff
, tuple
) == 0)
260 tuple
->dst
.protonum
= protonum
;
261 tuple
->dst
.dir
= IP_CT_DIR_ORIGINAL
;
263 return l4proto
->pkt_to_tuple(skb
, dataoff
, tuple
);
265 EXPORT_SYMBOL_GPL(nf_ct_get_tuple
);
268 nf_ct_invert_tuple(struct nf_conntrack_tuple
*inverse
,
269 const struct nf_conntrack_tuple
*orig
,
270 const struct nf_conntrack_l3proto
*l3proto
,
271 const struct nf_conntrack_l4proto
*l4proto
)
273 NF_CT_TUPLE_U_BLANK(inverse
);
275 inverse
->src
.l3num
= orig
->src
.l3num
;
276 if (l3proto
->invert_tuple(inverse
, orig
) == 0)
279 inverse
->dst
.dir
= !orig
->dst
.dir
;
281 inverse
->dst
.protonum
= orig
->dst
.protonum
;
282 return l4proto
->invert_tuple(inverse
, orig
);
284 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple
);
287 clean_from_lists(struct nf_conn
*ct
)
289 DEBUGP("clean_from_lists(%p)\n", ct
);
290 list_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
);
291 list_del(&ct
->tuplehash
[IP_CT_DIR_REPLY
].list
);
293 /* Destroy all pending expectations */
294 nf_ct_remove_expectations(ct
);
298 destroy_conntrack(struct nf_conntrack
*nfct
)
300 struct nf_conn
*ct
= (struct nf_conn
*)nfct
;
301 struct nf_conntrack_l4proto
*l4proto
;
302 typeof(nf_conntrack_destroyed
) destroyed
;
304 DEBUGP("destroy_conntrack(%p)\n", ct
);
305 NF_CT_ASSERT(atomic_read(&nfct
->use
) == 0);
306 NF_CT_ASSERT(!timer_pending(&ct
->timeout
));
308 nf_conntrack_event(IPCT_DESTROY
, ct
);
309 set_bit(IPS_DYING_BIT
, &ct
->status
);
311 /* To make sure we don't get any weird locking issues here:
312 * destroy_conntrack() MUST NOT be called with a write lock
313 * to nf_conntrack_lock!!! -HW */
315 l4proto
= __nf_ct_l4proto_find(ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.src
.l3num
,
316 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.protonum
);
317 if (l4proto
&& l4proto
->destroy
)
318 l4proto
->destroy(ct
);
320 destroyed
= rcu_dereference(nf_conntrack_destroyed
);
326 write_lock_bh(&nf_conntrack_lock
);
327 /* Expectations will have been removed in clean_from_lists,
328 * except TFTP can create an expectation on the first packet,
329 * before connection is in the list, so we need to clean here,
331 nf_ct_remove_expectations(ct
);
333 /* We overload first tuple to link into unconfirmed list. */
334 if (!nf_ct_is_confirmed(ct
)) {
335 BUG_ON(list_empty(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
));
336 list_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
);
339 NF_CT_STAT_INC(delete);
340 write_unlock_bh(&nf_conntrack_lock
);
343 nf_ct_put(ct
->master
);
345 DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct
);
346 nf_conntrack_free(ct
);
349 static void death_by_timeout(unsigned long ul_conntrack
)
351 struct nf_conn
*ct
= (void *)ul_conntrack
;
352 struct nf_conn_help
*help
= nfct_help(ct
);
353 struct nf_conntrack_helper
*helper
;
357 helper
= rcu_dereference(help
->helper
);
358 if (helper
&& helper
->destroy
)
363 write_lock_bh(&nf_conntrack_lock
);
364 /* Inside lock so preempt is disabled on module removal path.
365 * Otherwise we can get spurious warnings. */
366 NF_CT_STAT_INC(delete_list
);
367 clean_from_lists(ct
);
368 write_unlock_bh(&nf_conntrack_lock
);
372 struct nf_conntrack_tuple_hash
*
373 __nf_conntrack_find(const struct nf_conntrack_tuple
*tuple
,
374 const struct nf_conn
*ignored_conntrack
)
376 struct nf_conntrack_tuple_hash
*h
;
377 unsigned int hash
= hash_conntrack(tuple
);
379 list_for_each_entry(h
, &nf_conntrack_hash
[hash
], list
) {
380 if (nf_ct_tuplehash_to_ctrack(h
) != ignored_conntrack
&&
381 nf_ct_tuple_equal(tuple
, &h
->tuple
)) {
382 NF_CT_STAT_INC(found
);
385 NF_CT_STAT_INC(searched
);
390 EXPORT_SYMBOL_GPL(__nf_conntrack_find
);
392 /* Find a connection corresponding to a tuple. */
393 struct nf_conntrack_tuple_hash
*
394 nf_conntrack_find_get(const struct nf_conntrack_tuple
*tuple
,
395 const struct nf_conn
*ignored_conntrack
)
397 struct nf_conntrack_tuple_hash
*h
;
399 read_lock_bh(&nf_conntrack_lock
);
400 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
402 atomic_inc(&nf_ct_tuplehash_to_ctrack(h
)->ct_general
.use
);
403 read_unlock_bh(&nf_conntrack_lock
);
407 EXPORT_SYMBOL_GPL(nf_conntrack_find_get
);
409 static void __nf_conntrack_hash_insert(struct nf_conn
*ct
,
411 unsigned int repl_hash
)
413 ct
->id
= ++nf_conntrack_next_id
;
414 list_add(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
,
415 &nf_conntrack_hash
[hash
]);
416 list_add(&ct
->tuplehash
[IP_CT_DIR_REPLY
].list
,
417 &nf_conntrack_hash
[repl_hash
]);
420 void nf_conntrack_hash_insert(struct nf_conn
*ct
)
422 unsigned int hash
, repl_hash
;
424 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
425 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
427 write_lock_bh(&nf_conntrack_lock
);
428 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
429 write_unlock_bh(&nf_conntrack_lock
);
431 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert
);
433 /* Confirm a connection given skb; places it in hash table */
435 __nf_conntrack_confirm(struct sk_buff
**pskb
)
437 unsigned int hash
, repl_hash
;
438 struct nf_conntrack_tuple_hash
*h
;
440 struct nf_conn_help
*help
;
441 enum ip_conntrack_info ctinfo
;
443 ct
= nf_ct_get(*pskb
, &ctinfo
);
445 /* ipt_REJECT uses nf_conntrack_attach to attach related
446 ICMP/TCP RST packets in other direction. Actual packet
447 which created connection will be IP_CT_NEW or for an
448 expected connection, IP_CT_RELATED. */
449 if (CTINFO2DIR(ctinfo
) != IP_CT_DIR_ORIGINAL
)
452 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
453 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
455 /* We're not in hash table, and we refuse to set up related
456 connections for unconfirmed conns. But packet copies and
457 REJECT will give spurious warnings here. */
458 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
460 /* No external references means noone else could have
462 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
463 DEBUGP("Confirming conntrack %p\n", ct
);
465 write_lock_bh(&nf_conntrack_lock
);
467 /* See if there's one in the list already, including reverse:
468 NAT could have grabbed it without realizing, since we're
469 not in the hash. If there is, we lost race. */
470 list_for_each_entry(h
, &nf_conntrack_hash
[hash
], list
)
471 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
474 list_for_each_entry(h
, &nf_conntrack_hash
[repl_hash
], list
)
475 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
479 /* Remove from unconfirmed list */
480 list_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
);
482 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
483 /* Timer relative to confirmation time, not original
484 setting time, otherwise we'd get timer wrap in
485 weird delay cases. */
486 ct
->timeout
.expires
+= jiffies
;
487 add_timer(&ct
->timeout
);
488 atomic_inc(&ct
->ct_general
.use
);
489 set_bit(IPS_CONFIRMED_BIT
, &ct
->status
);
490 NF_CT_STAT_INC(insert
);
491 write_unlock_bh(&nf_conntrack_lock
);
492 help
= nfct_help(ct
);
493 if (help
&& help
->helper
)
494 nf_conntrack_event_cache(IPCT_HELPER
, *pskb
);
495 #ifdef CONFIG_NF_NAT_NEEDED
496 if (test_bit(IPS_SRC_NAT_DONE_BIT
, &ct
->status
) ||
497 test_bit(IPS_DST_NAT_DONE_BIT
, &ct
->status
))
498 nf_conntrack_event_cache(IPCT_NATINFO
, *pskb
);
500 nf_conntrack_event_cache(master_ct(ct
) ?
501 IPCT_RELATED
: IPCT_NEW
, *pskb
);
505 NF_CT_STAT_INC(insert_failed
);
506 write_unlock_bh(&nf_conntrack_lock
);
509 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm
);
511 /* Returns true if a connection correspondings to the tuple (required
514 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple
*tuple
,
515 const struct nf_conn
*ignored_conntrack
)
517 struct nf_conntrack_tuple_hash
*h
;
519 read_lock_bh(&nf_conntrack_lock
);
520 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
521 read_unlock_bh(&nf_conntrack_lock
);
525 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken
);
527 /* There's a small race here where we may free a just-assured
528 connection. Too bad: we're in trouble anyway. */
529 static int early_drop(struct list_head
*chain
)
531 /* Traverse backwards: gives us oldest, which is roughly LRU */
532 struct nf_conntrack_tuple_hash
*h
;
533 struct nf_conn
*ct
= NULL
, *tmp
;
536 read_lock_bh(&nf_conntrack_lock
);
537 list_for_each_entry_reverse(h
, chain
, list
) {
538 tmp
= nf_ct_tuplehash_to_ctrack(h
);
539 if (!test_bit(IPS_ASSURED_BIT
, &tmp
->status
)) {
541 atomic_inc(&ct
->ct_general
.use
);
545 read_unlock_bh(&nf_conntrack_lock
);
550 if (del_timer(&ct
->timeout
)) {
551 death_by_timeout((unsigned long)ct
);
553 NF_CT_STAT_INC_ATOMIC(early_drop
);
559 static struct nf_conn
*
560 __nf_conntrack_alloc(const struct nf_conntrack_tuple
*orig
,
561 const struct nf_conntrack_tuple
*repl
,
562 const struct nf_conntrack_l3proto
*l3proto
,
565 struct nf_conn
*conntrack
= NULL
;
566 struct nf_conntrack_helper
*helper
;
568 if (unlikely(!nf_conntrack_hash_rnd_initted
)) {
569 get_random_bytes(&nf_conntrack_hash_rnd
, 4);
570 nf_conntrack_hash_rnd_initted
= 1;
573 /* We don't want any race condition at early drop stage */
574 atomic_inc(&nf_conntrack_count
);
577 && atomic_read(&nf_conntrack_count
) > nf_conntrack_max
) {
578 unsigned int hash
= hash_conntrack(orig
);
579 /* Try dropping from this hash chain. */
580 if (!early_drop(&nf_conntrack_hash
[hash
])) {
581 atomic_dec(&nf_conntrack_count
);
584 "nf_conntrack: table full, dropping"
586 return ERR_PTR(-ENOMEM
);
590 /* find features needed by this conntrack. */
591 features
|= l3proto
->get_features(orig
);
593 /* FIXME: protect helper list per RCU */
594 read_lock_bh(&nf_conntrack_lock
);
595 helper
= __nf_ct_helper_find(repl
);
596 /* NAT might want to assign a helper later */
597 if (helper
|| features
& NF_CT_F_NAT
)
598 features
|= NF_CT_F_HELP
;
599 read_unlock_bh(&nf_conntrack_lock
);
601 DEBUGP("nf_conntrack_alloc: features=0x%x\n", features
);
603 read_lock_bh(&nf_ct_cache_lock
);
605 if (unlikely(!nf_ct_cache
[features
].use
)) {
606 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
611 conntrack
= kmem_cache_alloc(nf_ct_cache
[features
].cachep
, GFP_ATOMIC
);
612 if (conntrack
== NULL
) {
613 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
617 memset(conntrack
, 0, nf_ct_cache
[features
].size
);
618 conntrack
->features
= features
;
619 atomic_set(&conntrack
->ct_general
.use
, 1);
620 conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
= *orig
;
621 conntrack
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *repl
;
622 /* Don't set timer yet: wait for confirmation */
623 setup_timer(&conntrack
->timeout
, death_by_timeout
,
624 (unsigned long)conntrack
);
625 read_unlock_bh(&nf_ct_cache_lock
);
629 read_unlock_bh(&nf_ct_cache_lock
);
630 atomic_dec(&nf_conntrack_count
);
634 struct nf_conn
*nf_conntrack_alloc(const struct nf_conntrack_tuple
*orig
,
635 const struct nf_conntrack_tuple
*repl
)
637 struct nf_conntrack_l3proto
*l3proto
;
641 l3proto
= __nf_ct_l3proto_find(orig
->src
.l3num
);
642 ct
= __nf_conntrack_alloc(orig
, repl
, l3proto
, 0);
647 EXPORT_SYMBOL_GPL(nf_conntrack_alloc
);
649 void nf_conntrack_free(struct nf_conn
*conntrack
)
651 u_int32_t features
= conntrack
->features
;
652 NF_CT_ASSERT(features
>= NF_CT_F_BASIC
&& features
< NF_CT_F_NUM
);
653 DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features
,
655 kmem_cache_free(nf_ct_cache
[features
].cachep
, conntrack
);
656 atomic_dec(&nf_conntrack_count
);
658 EXPORT_SYMBOL_GPL(nf_conntrack_free
);
660 /* Allocate a new conntrack: we return -ENOMEM if classification
661 failed due to stress. Otherwise it really is unclassifiable. */
662 static struct nf_conntrack_tuple_hash
*
663 init_conntrack(const struct nf_conntrack_tuple
*tuple
,
664 struct nf_conntrack_l3proto
*l3proto
,
665 struct nf_conntrack_l4proto
*l4proto
,
667 unsigned int dataoff
)
669 struct nf_conn
*conntrack
;
670 struct nf_conn_help
*help
;
671 struct nf_conntrack_tuple repl_tuple
;
672 struct nf_conntrack_expect
*exp
;
673 u_int32_t features
= 0;
675 if (!nf_ct_invert_tuple(&repl_tuple
, tuple
, l3proto
, l4proto
)) {
676 DEBUGP("Can't invert tuple.\n");
680 read_lock_bh(&nf_conntrack_lock
);
681 exp
= __nf_conntrack_expect_find(tuple
);
682 if (exp
&& exp
->helper
)
683 features
= NF_CT_F_HELP
;
684 read_unlock_bh(&nf_conntrack_lock
);
686 conntrack
= __nf_conntrack_alloc(tuple
, &repl_tuple
, l3proto
, features
);
687 if (conntrack
== NULL
|| IS_ERR(conntrack
)) {
688 DEBUGP("Can't allocate conntrack.\n");
689 return (struct nf_conntrack_tuple_hash
*)conntrack
;
692 if (!l4proto
->new(conntrack
, skb
, dataoff
)) {
693 nf_conntrack_free(conntrack
);
694 DEBUGP("init conntrack: can't track with proto module\n");
698 write_lock_bh(&nf_conntrack_lock
);
699 exp
= find_expectation(tuple
);
701 help
= nfct_help(conntrack
);
703 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
705 /* Welcome, Mr. Bond. We've been expecting you... */
706 __set_bit(IPS_EXPECTED_BIT
, &conntrack
->status
);
707 conntrack
->master
= exp
->master
;
709 rcu_assign_pointer(help
->helper
, exp
->helper
);
710 #ifdef CONFIG_NF_CONNTRACK_MARK
711 conntrack
->mark
= exp
->master
->mark
;
713 #ifdef CONFIG_NF_CONNTRACK_SECMARK
714 conntrack
->secmark
= exp
->master
->secmark
;
716 nf_conntrack_get(&conntrack
->master
->ct_general
);
717 NF_CT_STAT_INC(expect_new
);
720 /* not in hash table yet, so not strictly necessary */
721 rcu_assign_pointer(help
->helper
,
722 __nf_ct_helper_find(&repl_tuple
));
727 /* Overload tuple linked list to put us in unconfirmed list. */
728 list_add(&conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
, &unconfirmed
);
730 write_unlock_bh(&nf_conntrack_lock
);
734 exp
->expectfn(conntrack
, exp
);
735 nf_conntrack_expect_put(exp
);
738 return &conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
];
741 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
742 static inline struct nf_conn
*
743 resolve_normal_ct(struct sk_buff
*skb
,
744 unsigned int dataoff
,
747 struct nf_conntrack_l3proto
*l3proto
,
748 struct nf_conntrack_l4proto
*l4proto
,
750 enum ip_conntrack_info
*ctinfo
)
752 struct nf_conntrack_tuple tuple
;
753 struct nf_conntrack_tuple_hash
*h
;
756 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
),
757 dataoff
, l3num
, protonum
, &tuple
, l3proto
,
759 DEBUGP("resolve_normal_ct: Can't get tuple\n");
763 /* look for tuple match */
764 h
= nf_conntrack_find_get(&tuple
, NULL
);
766 h
= init_conntrack(&tuple
, l3proto
, l4proto
, skb
, dataoff
);
772 ct
= nf_ct_tuplehash_to_ctrack(h
);
774 /* It exists; we have (non-exclusive) reference. */
775 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
) {
776 *ctinfo
= IP_CT_ESTABLISHED
+ IP_CT_IS_REPLY
;
777 /* Please set reply bit if this packet OK */
780 /* Once we've had two way comms, always ESTABLISHED. */
781 if (test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
782 DEBUGP("nf_conntrack_in: normal packet for %p\n", ct
);
783 *ctinfo
= IP_CT_ESTABLISHED
;
784 } else if (test_bit(IPS_EXPECTED_BIT
, &ct
->status
)) {
785 DEBUGP("nf_conntrack_in: related packet for %p\n", ct
);
786 *ctinfo
= IP_CT_RELATED
;
788 DEBUGP("nf_conntrack_in: new packet for %p\n", ct
);
793 skb
->nfct
= &ct
->ct_general
;
794 skb
->nfctinfo
= *ctinfo
;
799 nf_conntrack_in(int pf
, unsigned int hooknum
, struct sk_buff
**pskb
)
802 enum ip_conntrack_info ctinfo
;
803 struct nf_conntrack_l3proto
*l3proto
;
804 struct nf_conntrack_l4proto
*l4proto
;
805 unsigned int dataoff
;
810 /* Previously seen (loopback or untracked)? Ignore. */
812 NF_CT_STAT_INC_ATOMIC(ignore
);
816 /* rcu_read_lock()ed by nf_hook_slow */
817 l3proto
= __nf_ct_l3proto_find((u_int16_t
)pf
);
819 if ((ret
= l3proto
->prepare(pskb
, hooknum
, &dataoff
, &protonum
)) <= 0) {
820 DEBUGP("not prepared to track yet or error occured\n");
824 l4proto
= __nf_ct_l4proto_find((u_int16_t
)pf
, protonum
);
826 /* It may be an special packet, error, unclean...
827 * inverse of the return code tells to the netfilter
828 * core what to do with the packet. */
829 if (l4proto
->error
!= NULL
&&
830 (ret
= l4proto
->error(*pskb
, dataoff
, &ctinfo
, pf
, hooknum
)) <= 0) {
831 NF_CT_STAT_INC_ATOMIC(error
);
832 NF_CT_STAT_INC_ATOMIC(invalid
);
836 ct
= resolve_normal_ct(*pskb
, dataoff
, pf
, protonum
, l3proto
, l4proto
,
837 &set_reply
, &ctinfo
);
839 /* Not valid part of a connection */
840 NF_CT_STAT_INC_ATOMIC(invalid
);
845 /* Too stressed to deal. */
846 NF_CT_STAT_INC_ATOMIC(drop
);
850 NF_CT_ASSERT((*pskb
)->nfct
);
852 ret
= l4proto
->packet(ct
, *pskb
, dataoff
, ctinfo
, pf
, hooknum
);
854 /* Invalid: inverse of the return code tells
855 * the netfilter core what to do */
856 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
857 nf_conntrack_put((*pskb
)->nfct
);
858 (*pskb
)->nfct
= NULL
;
859 NF_CT_STAT_INC_ATOMIC(invalid
);
863 if (set_reply
&& !test_and_set_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
))
864 nf_conntrack_event_cache(IPCT_STATUS
, *pskb
);
868 EXPORT_SYMBOL_GPL(nf_conntrack_in
);
870 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple
*inverse
,
871 const struct nf_conntrack_tuple
*orig
)
876 ret
= nf_ct_invert_tuple(inverse
, orig
,
877 __nf_ct_l3proto_find(orig
->src
.l3num
),
878 __nf_ct_l4proto_find(orig
->src
.l3num
,
879 orig
->dst
.protonum
));
883 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr
);
885 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
886 implicitly racy: see __nf_conntrack_confirm */
887 void nf_conntrack_alter_reply(struct nf_conn
*ct
,
888 const struct nf_conntrack_tuple
*newreply
)
890 struct nf_conn_help
*help
= nfct_help(ct
);
892 write_lock_bh(&nf_conntrack_lock
);
893 /* Should be unconfirmed, so not in hash table yet */
894 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
896 DEBUGP("Altering reply tuple of %p to ", ct
);
897 NF_CT_DUMP_TUPLE(newreply
);
899 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *newreply
;
900 if (!ct
->master
&& help
&& help
->expecting
== 0) {
901 struct nf_conntrack_helper
*helper
;
902 helper
= __nf_ct_helper_find(newreply
);
904 memset(&help
->help
, 0, sizeof(help
->help
));
905 /* not in hash table yet, so not strictly necessary */
906 rcu_assign_pointer(help
->helper
, helper
);
908 write_unlock_bh(&nf_conntrack_lock
);
910 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply
);
912 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
913 void __nf_ct_refresh_acct(struct nf_conn
*ct
,
914 enum ip_conntrack_info ctinfo
,
915 const struct sk_buff
*skb
,
916 unsigned long extra_jiffies
,
921 NF_CT_ASSERT(ct
->timeout
.data
== (unsigned long)ct
);
924 write_lock_bh(&nf_conntrack_lock
);
926 /* Only update if this is not a fixed timeout */
927 if (test_bit(IPS_FIXED_TIMEOUT_BIT
, &ct
->status
)) {
928 write_unlock_bh(&nf_conntrack_lock
);
932 /* If not in hash table, timer will not be active yet */
933 if (!nf_ct_is_confirmed(ct
)) {
934 ct
->timeout
.expires
= extra_jiffies
;
935 event
= IPCT_REFRESH
;
937 unsigned long newtime
= jiffies
+ extra_jiffies
;
939 /* Only update the timeout if the new timeout is at least
940 HZ jiffies from the old timeout. Need del_timer for race
941 avoidance (may already be dying). */
942 if (newtime
- ct
->timeout
.expires
>= HZ
943 && del_timer(&ct
->timeout
)) {
944 ct
->timeout
.expires
= newtime
;
945 add_timer(&ct
->timeout
);
946 event
= IPCT_REFRESH
;
950 #ifdef CONFIG_NF_CT_ACCT
952 ct
->counters
[CTINFO2DIR(ctinfo
)].packets
++;
953 ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
+=
954 skb
->len
- skb_network_offset(skb
);
956 if ((ct
->counters
[CTINFO2DIR(ctinfo
)].packets
& 0x80000000)
957 || (ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
& 0x80000000))
958 event
|= IPCT_COUNTER_FILLING
;
962 write_unlock_bh(&nf_conntrack_lock
);
964 /* must be unlocked when calling event cache */
966 nf_conntrack_event_cache(event
, skb
);
968 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct
);
970 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
972 #include <linux/netfilter/nfnetlink.h>
973 #include <linux/netfilter/nfnetlink_conntrack.h>
974 #include <linux/mutex.h>
977 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
978 * in ip_conntrack_core, since we don't want the protocols to autoload
979 * or depend on ctnetlink */
980 int nf_ct_port_tuple_to_nfattr(struct sk_buff
*skb
,
981 const struct nf_conntrack_tuple
*tuple
)
983 NFA_PUT(skb
, CTA_PROTO_SRC_PORT
, sizeof(u_int16_t
),
984 &tuple
->src
.u
.tcp
.port
);
985 NFA_PUT(skb
, CTA_PROTO_DST_PORT
, sizeof(u_int16_t
),
986 &tuple
->dst
.u
.tcp
.port
);
992 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr
);
994 static const size_t cta_min_proto
[CTA_PROTO_MAX
] = {
995 [CTA_PROTO_SRC_PORT
-1] = sizeof(u_int16_t
),
996 [CTA_PROTO_DST_PORT
-1] = sizeof(u_int16_t
)
999 int nf_ct_port_nfattr_to_tuple(struct nfattr
*tb
[],
1000 struct nf_conntrack_tuple
*t
)
1002 if (!tb
[CTA_PROTO_SRC_PORT
-1] || !tb
[CTA_PROTO_DST_PORT
-1])
1005 if (nfattr_bad_size(tb
, CTA_PROTO_MAX
, cta_min_proto
))
1008 t
->src
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_SRC_PORT
-1]);
1009 t
->dst
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_DST_PORT
-1]);
1013 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple
);
1016 /* Used by ipt_REJECT and ip6t_REJECT. */
1017 void __nf_conntrack_attach(struct sk_buff
*nskb
, struct sk_buff
*skb
)
1020 enum ip_conntrack_info ctinfo
;
1022 /* This ICMP is in reverse direction to the packet which caused it */
1023 ct
= nf_ct_get(skb
, &ctinfo
);
1024 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
)
1025 ctinfo
= IP_CT_RELATED
+ IP_CT_IS_REPLY
;
1027 ctinfo
= IP_CT_RELATED
;
1029 /* Attach to new skbuff, and increment count */
1030 nskb
->nfct
= &ct
->ct_general
;
1031 nskb
->nfctinfo
= ctinfo
;
1032 nf_conntrack_get(nskb
->nfct
);
1034 EXPORT_SYMBOL_GPL(__nf_conntrack_attach
);
1037 do_iter(const struct nf_conntrack_tuple_hash
*i
,
1038 int (*iter
)(struct nf_conn
*i
, void *data
),
1041 return iter(nf_ct_tuplehash_to_ctrack(i
), data
);
1044 /* Bring out ya dead! */
1045 static struct nf_conn
*
1046 get_next_corpse(int (*iter
)(struct nf_conn
*i
, void *data
),
1047 void *data
, unsigned int *bucket
)
1049 struct nf_conntrack_tuple_hash
*h
;
1052 write_lock_bh(&nf_conntrack_lock
);
1053 for (; *bucket
< nf_conntrack_htable_size
; (*bucket
)++) {
1054 list_for_each_entry(h
, &nf_conntrack_hash
[*bucket
], list
) {
1055 ct
= nf_ct_tuplehash_to_ctrack(h
);
1060 list_for_each_entry(h
, &unconfirmed
, list
) {
1061 ct
= nf_ct_tuplehash_to_ctrack(h
);
1063 set_bit(IPS_DYING_BIT
, &ct
->status
);
1065 write_unlock_bh(&nf_conntrack_lock
);
1068 atomic_inc(&ct
->ct_general
.use
);
1069 write_unlock_bh(&nf_conntrack_lock
);
1074 nf_ct_iterate_cleanup(int (*iter
)(struct nf_conn
*i
, void *data
), void *data
)
1077 unsigned int bucket
= 0;
1079 while ((ct
= get_next_corpse(iter
, data
, &bucket
)) != NULL
) {
1080 /* Time to push up daises... */
1081 if (del_timer(&ct
->timeout
))
1082 death_by_timeout((unsigned long)ct
);
1083 /* ... else the timer will get him soon. */
1088 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup
);
1090 static int kill_all(struct nf_conn
*i
, void *data
)
1095 static void free_conntrack_hash(struct list_head
*hash
, int vmalloced
, int size
)
1100 free_pages((unsigned long)hash
,
1101 get_order(sizeof(struct list_head
) * size
));
1104 void nf_conntrack_flush(void)
1106 nf_ct_iterate_cleanup(kill_all
, NULL
);
1108 EXPORT_SYMBOL_GPL(nf_conntrack_flush
);
1110 /* Mishearing the voices in his head, our hero wonders how he's
1111 supposed to kill the mall. */
1112 void nf_conntrack_cleanup(void)
1116 rcu_assign_pointer(ip_ct_attach
, NULL
);
1118 /* This makes sure all current packets have passed through
1119 netfilter framework. Roll on, two-stage module
1123 nf_ct_event_cache_flush();
1125 nf_conntrack_flush();
1126 if (atomic_read(&nf_conntrack_count
) != 0) {
1128 goto i_see_dead_people
;
1130 /* wait until all references to nf_conntrack_untracked are dropped */
1131 while (atomic_read(&nf_conntrack_untracked
.ct_general
.use
) > 1)
1134 rcu_assign_pointer(nf_ct_destroy
, NULL
);
1136 for (i
= 0; i
< NF_CT_F_NUM
; i
++) {
1137 if (nf_ct_cache
[i
].use
== 0)
1140 NF_CT_ASSERT(nf_ct_cache
[i
].use
== 1);
1141 nf_ct_cache
[i
].use
= 1;
1142 nf_conntrack_unregister_cache(i
);
1144 kmem_cache_destroy(nf_conntrack_expect_cachep
);
1145 free_conntrack_hash(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1146 nf_conntrack_htable_size
);
1148 nf_conntrack_proto_fini();
1151 static struct list_head
*alloc_hashtable(int size
, int *vmalloced
)
1153 struct list_head
*hash
;
1157 hash
= (void*)__get_free_pages(GFP_KERNEL
,
1158 get_order(sizeof(struct list_head
)
1162 printk(KERN_WARNING
"nf_conntrack: falling back to vmalloc.\n");
1163 hash
= vmalloc(sizeof(struct list_head
) * size
);
1167 for (i
= 0; i
< size
; i
++)
1168 INIT_LIST_HEAD(&hash
[i
]);
1173 int set_hashsize(const char *val
, struct kernel_param
*kp
)
1175 int i
, bucket
, hashsize
, vmalloced
;
1176 int old_vmalloced
, old_size
;
1178 struct list_head
*hash
, *old_hash
;
1179 struct nf_conntrack_tuple_hash
*h
;
1181 /* On boot, we can set this without any fancy locking. */
1182 if (!nf_conntrack_htable_size
)
1183 return param_set_uint(val
, kp
);
1185 hashsize
= simple_strtol(val
, NULL
, 0);
1189 hash
= alloc_hashtable(hashsize
, &vmalloced
);
1193 /* We have to rehahs for the new table anyway, so we also can
1194 * use a newrandom seed */
1195 get_random_bytes(&rnd
, 4);
1197 write_lock_bh(&nf_conntrack_lock
);
1198 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
1199 while (!list_empty(&nf_conntrack_hash
[i
])) {
1200 h
= list_entry(nf_conntrack_hash
[i
].next
,
1201 struct nf_conntrack_tuple_hash
, list
);
1203 bucket
= __hash_conntrack(&h
->tuple
, hashsize
, rnd
);
1204 list_add_tail(&h
->list
, &hash
[bucket
]);
1207 old_size
= nf_conntrack_htable_size
;
1208 old_vmalloced
= nf_conntrack_vmalloc
;
1209 old_hash
= nf_conntrack_hash
;
1211 nf_conntrack_htable_size
= hashsize
;
1212 nf_conntrack_vmalloc
= vmalloced
;
1213 nf_conntrack_hash
= hash
;
1214 nf_conntrack_hash_rnd
= rnd
;
1215 write_unlock_bh(&nf_conntrack_lock
);
1217 free_conntrack_hash(old_hash
, old_vmalloced
, old_size
);
1221 module_param_call(hashsize
, set_hashsize
, param_get_uint
,
1222 &nf_conntrack_htable_size
, 0600);
1224 int __init
nf_conntrack_init(void)
1228 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1229 * machine has 256 buckets. >= 1GB machines have 8192 buckets. */
1230 if (!nf_conntrack_htable_size
) {
1231 nf_conntrack_htable_size
1232 = (((num_physpages
<< PAGE_SHIFT
) / 16384)
1233 / sizeof(struct list_head
));
1234 if (num_physpages
> (1024 * 1024 * 1024 / PAGE_SIZE
))
1235 nf_conntrack_htable_size
= 8192;
1236 if (nf_conntrack_htable_size
< 16)
1237 nf_conntrack_htable_size
= 16;
1239 nf_conntrack_max
= 8 * nf_conntrack_htable_size
;
1241 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1242 NF_CONNTRACK_VERSION
, nf_conntrack_htable_size
,
1245 nf_conntrack_hash
= alloc_hashtable(nf_conntrack_htable_size
,
1246 &nf_conntrack_vmalloc
);
1247 if (!nf_conntrack_hash
) {
1248 printk(KERN_ERR
"Unable to create nf_conntrack_hash\n");
1252 ret
= nf_conntrack_register_cache(NF_CT_F_BASIC
, "nf_conntrack:basic",
1253 sizeof(struct nf_conn
));
1255 printk(KERN_ERR
"Unable to create nf_conn slab cache\n");
1259 nf_conntrack_expect_cachep
= kmem_cache_create("nf_conntrack_expect",
1260 sizeof(struct nf_conntrack_expect
),
1262 if (!nf_conntrack_expect_cachep
) {
1263 printk(KERN_ERR
"Unable to create nf_expect slab cache\n");
1264 goto err_free_conntrack_slab
;
1267 ret
= nf_conntrack_proto_init();
1269 goto out_free_expect_slab
;
1271 /* For use by REJECT target */
1272 rcu_assign_pointer(ip_ct_attach
, __nf_conntrack_attach
);
1273 rcu_assign_pointer(nf_ct_destroy
, destroy_conntrack
);
1275 /* Set up fake conntrack:
1276 - to never be deleted, not in any hashes */
1277 atomic_set(&nf_conntrack_untracked
.ct_general
.use
, 1);
1278 /* - and look it like as a confirmed connection */
1279 set_bit(IPS_CONFIRMED_BIT
, &nf_conntrack_untracked
.status
);
1283 out_free_expect_slab
:
1284 kmem_cache_destroy(nf_conntrack_expect_cachep
);
1285 err_free_conntrack_slab
:
1286 nf_conntrack_unregister_cache(NF_CT_F_BASIC
);
1288 free_conntrack_hash(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1289 nf_conntrack_htable_size
);