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 unsigned int nf_conntrack_htable_size __read_mostly
;
57 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size
);
59 int nf_conntrack_max __read_mostly
;
60 EXPORT_SYMBOL_GPL(nf_conntrack_max
);
62 struct hlist_head
*nf_conntrack_hash __read_mostly
;
63 EXPORT_SYMBOL_GPL(nf_conntrack_hash
);
65 struct nf_conn nf_conntrack_untracked __read_mostly
;
66 EXPORT_SYMBOL_GPL(nf_conntrack_untracked
);
68 unsigned int nf_ct_log_invalid __read_mostly
;
69 HLIST_HEAD(unconfirmed
);
70 static int nf_conntrack_vmalloc __read_mostly
;
71 static struct kmem_cache
*nf_conntrack_cachep __read_mostly
;
72 static unsigned int nf_conntrack_next_id
;
74 DEFINE_PER_CPU(struct ip_conntrack_stat
, nf_conntrack_stat
);
75 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat
);
77 static int nf_conntrack_hash_rnd_initted
;
78 static unsigned int nf_conntrack_hash_rnd
;
80 static u_int32_t
__hash_conntrack(const struct nf_conntrack_tuple
*tuple
,
81 unsigned int size
, unsigned int rnd
)
85 a
= jhash2(tuple
->src
.u3
.all
, ARRAY_SIZE(tuple
->src
.u3
.all
),
86 (tuple
->src
.l3num
<< 16) | tuple
->dst
.protonum
);
87 b
= jhash2(tuple
->dst
.u3
.all
, ARRAY_SIZE(tuple
->dst
.u3
.all
),
88 (tuple
->src
.u
.all
<< 16) | tuple
->dst
.u
.all
);
90 return jhash_2words(a
, b
, rnd
) % size
;
93 static inline u_int32_t
hash_conntrack(const struct nf_conntrack_tuple
*tuple
)
95 return __hash_conntrack(tuple
, nf_conntrack_htable_size
,
96 nf_conntrack_hash_rnd
);
100 nf_ct_get_tuple(const struct sk_buff
*skb
,
102 unsigned int dataoff
,
105 struct nf_conntrack_tuple
*tuple
,
106 const struct nf_conntrack_l3proto
*l3proto
,
107 const struct nf_conntrack_l4proto
*l4proto
)
109 NF_CT_TUPLE_U_BLANK(tuple
);
111 tuple
->src
.l3num
= l3num
;
112 if (l3proto
->pkt_to_tuple(skb
, nhoff
, tuple
) == 0)
115 tuple
->dst
.protonum
= protonum
;
116 tuple
->dst
.dir
= IP_CT_DIR_ORIGINAL
;
118 return l4proto
->pkt_to_tuple(skb
, dataoff
, tuple
);
120 EXPORT_SYMBOL_GPL(nf_ct_get_tuple
);
123 nf_ct_invert_tuple(struct nf_conntrack_tuple
*inverse
,
124 const struct nf_conntrack_tuple
*orig
,
125 const struct nf_conntrack_l3proto
*l3proto
,
126 const struct nf_conntrack_l4proto
*l4proto
)
128 NF_CT_TUPLE_U_BLANK(inverse
);
130 inverse
->src
.l3num
= orig
->src
.l3num
;
131 if (l3proto
->invert_tuple(inverse
, orig
) == 0)
134 inverse
->dst
.dir
= !orig
->dst
.dir
;
136 inverse
->dst
.protonum
= orig
->dst
.protonum
;
137 return l4proto
->invert_tuple(inverse
, orig
);
139 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple
);
142 clean_from_lists(struct nf_conn
*ct
)
144 DEBUGP("clean_from_lists(%p)\n", ct
);
145 hlist_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
);
146 hlist_del(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnode
);
148 /* Destroy all pending expectations */
149 nf_ct_remove_expectations(ct
);
153 destroy_conntrack(struct nf_conntrack
*nfct
)
155 struct nf_conn
*ct
= (struct nf_conn
*)nfct
;
156 struct nf_conntrack_l4proto
*l4proto
;
158 DEBUGP("destroy_conntrack(%p)\n", ct
);
159 NF_CT_ASSERT(atomic_read(&nfct
->use
) == 0);
160 NF_CT_ASSERT(!timer_pending(&ct
->timeout
));
162 nf_conntrack_event(IPCT_DESTROY
, ct
);
163 set_bit(IPS_DYING_BIT
, &ct
->status
);
165 /* To make sure we don't get any weird locking issues here:
166 * destroy_conntrack() MUST NOT be called with a write lock
167 * to nf_conntrack_lock!!! -HW */
169 l4proto
= __nf_ct_l4proto_find(ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.src
.l3num
,
170 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.protonum
);
171 if (l4proto
&& l4proto
->destroy
)
172 l4proto
->destroy(ct
);
174 nf_ct_ext_destroy(ct
);
178 write_lock_bh(&nf_conntrack_lock
);
179 /* Expectations will have been removed in clean_from_lists,
180 * except TFTP can create an expectation on the first packet,
181 * before connection is in the list, so we need to clean here,
183 nf_ct_remove_expectations(ct
);
185 /* We overload first tuple to link into unconfirmed list. */
186 if (!nf_ct_is_confirmed(ct
)) {
187 BUG_ON(hlist_unhashed(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
));
188 hlist_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
);
191 NF_CT_STAT_INC(delete);
192 write_unlock_bh(&nf_conntrack_lock
);
195 nf_ct_put(ct
->master
);
197 DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct
);
198 nf_conntrack_free(ct
);
201 static void death_by_timeout(unsigned long ul_conntrack
)
203 struct nf_conn
*ct
= (void *)ul_conntrack
;
204 struct nf_conn_help
*help
= nfct_help(ct
);
205 struct nf_conntrack_helper
*helper
;
209 helper
= rcu_dereference(help
->helper
);
210 if (helper
&& helper
->destroy
)
215 write_lock_bh(&nf_conntrack_lock
);
216 /* Inside lock so preempt is disabled on module removal path.
217 * Otherwise we can get spurious warnings. */
218 NF_CT_STAT_INC(delete_list
);
219 clean_from_lists(ct
);
220 write_unlock_bh(&nf_conntrack_lock
);
224 struct nf_conntrack_tuple_hash
*
225 __nf_conntrack_find(const struct nf_conntrack_tuple
*tuple
,
226 const struct nf_conn
*ignored_conntrack
)
228 struct nf_conntrack_tuple_hash
*h
;
229 struct hlist_node
*n
;
230 unsigned int hash
= hash_conntrack(tuple
);
232 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[hash
], hnode
) {
233 if (nf_ct_tuplehash_to_ctrack(h
) != ignored_conntrack
&&
234 nf_ct_tuple_equal(tuple
, &h
->tuple
)) {
235 NF_CT_STAT_INC(found
);
238 NF_CT_STAT_INC(searched
);
243 EXPORT_SYMBOL_GPL(__nf_conntrack_find
);
245 /* Find a connection corresponding to a tuple. */
246 struct nf_conntrack_tuple_hash
*
247 nf_conntrack_find_get(const struct nf_conntrack_tuple
*tuple
)
249 struct nf_conntrack_tuple_hash
*h
;
251 read_lock_bh(&nf_conntrack_lock
);
252 h
= __nf_conntrack_find(tuple
, NULL
);
254 atomic_inc(&nf_ct_tuplehash_to_ctrack(h
)->ct_general
.use
);
255 read_unlock_bh(&nf_conntrack_lock
);
259 EXPORT_SYMBOL_GPL(nf_conntrack_find_get
);
261 static void __nf_conntrack_hash_insert(struct nf_conn
*ct
,
263 unsigned int repl_hash
)
265 ct
->id
= ++nf_conntrack_next_id
;
266 hlist_add_head(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
,
267 &nf_conntrack_hash
[hash
]);
268 hlist_add_head(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnode
,
269 &nf_conntrack_hash
[repl_hash
]);
272 void nf_conntrack_hash_insert(struct nf_conn
*ct
)
274 unsigned int hash
, repl_hash
;
276 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
277 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
279 write_lock_bh(&nf_conntrack_lock
);
280 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
281 write_unlock_bh(&nf_conntrack_lock
);
283 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert
);
285 /* Confirm a connection given skb; places it in hash table */
287 __nf_conntrack_confirm(struct sk_buff
**pskb
)
289 unsigned int hash
, repl_hash
;
290 struct nf_conntrack_tuple_hash
*h
;
292 struct nf_conn_help
*help
;
293 struct hlist_node
*n
;
294 enum ip_conntrack_info ctinfo
;
296 ct
= nf_ct_get(*pskb
, &ctinfo
);
298 /* ipt_REJECT uses nf_conntrack_attach to attach related
299 ICMP/TCP RST packets in other direction. Actual packet
300 which created connection will be IP_CT_NEW or for an
301 expected connection, IP_CT_RELATED. */
302 if (CTINFO2DIR(ctinfo
) != IP_CT_DIR_ORIGINAL
)
305 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
306 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
308 /* We're not in hash table, and we refuse to set up related
309 connections for unconfirmed conns. But packet copies and
310 REJECT will give spurious warnings here. */
311 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
313 /* No external references means noone else could have
315 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
316 DEBUGP("Confirming conntrack %p\n", ct
);
318 write_lock_bh(&nf_conntrack_lock
);
320 /* See if there's one in the list already, including reverse:
321 NAT could have grabbed it without realizing, since we're
322 not in the hash. If there is, we lost race. */
323 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[hash
], hnode
)
324 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
327 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[repl_hash
], hnode
)
328 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
332 /* Remove from unconfirmed list */
333 hlist_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
);
335 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
336 /* Timer relative to confirmation time, not original
337 setting time, otherwise we'd get timer wrap in
338 weird delay cases. */
339 ct
->timeout
.expires
+= jiffies
;
340 add_timer(&ct
->timeout
);
341 atomic_inc(&ct
->ct_general
.use
);
342 set_bit(IPS_CONFIRMED_BIT
, &ct
->status
);
343 NF_CT_STAT_INC(insert
);
344 write_unlock_bh(&nf_conntrack_lock
);
345 help
= nfct_help(ct
);
346 if (help
&& help
->helper
)
347 nf_conntrack_event_cache(IPCT_HELPER
, *pskb
);
348 #ifdef CONFIG_NF_NAT_NEEDED
349 if (test_bit(IPS_SRC_NAT_DONE_BIT
, &ct
->status
) ||
350 test_bit(IPS_DST_NAT_DONE_BIT
, &ct
->status
))
351 nf_conntrack_event_cache(IPCT_NATINFO
, *pskb
);
353 nf_conntrack_event_cache(master_ct(ct
) ?
354 IPCT_RELATED
: IPCT_NEW
, *pskb
);
358 NF_CT_STAT_INC(insert_failed
);
359 write_unlock_bh(&nf_conntrack_lock
);
362 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm
);
364 /* Returns true if a connection correspondings to the tuple (required
367 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple
*tuple
,
368 const struct nf_conn
*ignored_conntrack
)
370 struct nf_conntrack_tuple_hash
*h
;
372 read_lock_bh(&nf_conntrack_lock
);
373 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
374 read_unlock_bh(&nf_conntrack_lock
);
378 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken
);
380 /* There's a small race here where we may free a just-assured
381 connection. Too bad: we're in trouble anyway. */
382 static int early_drop(struct hlist_head
*chain
)
384 /* Use oldest entry, which is roughly LRU */
385 struct nf_conntrack_tuple_hash
*h
;
386 struct nf_conn
*ct
= NULL
, *tmp
;
387 struct hlist_node
*n
;
390 read_lock_bh(&nf_conntrack_lock
);
391 hlist_for_each_entry(h
, n
, chain
, hnode
) {
392 tmp
= nf_ct_tuplehash_to_ctrack(h
);
393 if (!test_bit(IPS_ASSURED_BIT
, &tmp
->status
))
397 atomic_inc(&ct
->ct_general
.use
);
398 read_unlock_bh(&nf_conntrack_lock
);
403 if (del_timer(&ct
->timeout
)) {
404 death_by_timeout((unsigned long)ct
);
406 NF_CT_STAT_INC_ATOMIC(early_drop
);
412 struct nf_conn
*nf_conntrack_alloc(const struct nf_conntrack_tuple
*orig
,
413 const struct nf_conntrack_tuple
*repl
)
415 struct nf_conn
*conntrack
= NULL
;
417 if (unlikely(!nf_conntrack_hash_rnd_initted
)) {
418 get_random_bytes(&nf_conntrack_hash_rnd
, 4);
419 nf_conntrack_hash_rnd_initted
= 1;
422 /* We don't want any race condition at early drop stage */
423 atomic_inc(&nf_conntrack_count
);
426 && atomic_read(&nf_conntrack_count
) > nf_conntrack_max
) {
427 unsigned int hash
= hash_conntrack(orig
);
428 /* Try dropping from this hash chain. */
429 if (!early_drop(&nf_conntrack_hash
[hash
])) {
430 atomic_dec(&nf_conntrack_count
);
433 "nf_conntrack: table full, dropping"
435 return ERR_PTR(-ENOMEM
);
439 conntrack
= kmem_cache_zalloc(nf_conntrack_cachep
, GFP_ATOMIC
);
440 if (conntrack
== NULL
) {
441 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack.\n");
442 atomic_dec(&nf_conntrack_count
);
443 return ERR_PTR(-ENOMEM
);
446 atomic_set(&conntrack
->ct_general
.use
, 1);
447 conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
= *orig
;
448 conntrack
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *repl
;
449 /* Don't set timer yet: wait for confirmation */
450 setup_timer(&conntrack
->timeout
, death_by_timeout
,
451 (unsigned long)conntrack
);
455 EXPORT_SYMBOL_GPL(nf_conntrack_alloc
);
457 void nf_conntrack_free(struct nf_conn
*conntrack
)
459 nf_ct_ext_free(conntrack
);
460 kmem_cache_free(nf_conntrack_cachep
, conntrack
);
461 atomic_dec(&nf_conntrack_count
);
463 EXPORT_SYMBOL_GPL(nf_conntrack_free
);
465 /* Allocate a new conntrack: we return -ENOMEM if classification
466 failed due to stress. Otherwise it really is unclassifiable. */
467 static struct nf_conntrack_tuple_hash
*
468 init_conntrack(const struct nf_conntrack_tuple
*tuple
,
469 struct nf_conntrack_l3proto
*l3proto
,
470 struct nf_conntrack_l4proto
*l4proto
,
472 unsigned int dataoff
)
474 struct nf_conn
*conntrack
;
475 struct nf_conn_help
*help
;
476 struct nf_conntrack_tuple repl_tuple
;
477 struct nf_conntrack_expect
*exp
;
479 if (!nf_ct_invert_tuple(&repl_tuple
, tuple
, l3proto
, l4proto
)) {
480 DEBUGP("Can't invert tuple.\n");
484 conntrack
= nf_conntrack_alloc(tuple
, &repl_tuple
);
485 if (conntrack
== NULL
|| IS_ERR(conntrack
)) {
486 DEBUGP("Can't allocate conntrack.\n");
487 return (struct nf_conntrack_tuple_hash
*)conntrack
;
490 if (!l4proto
->new(conntrack
, skb
, dataoff
)) {
491 nf_conntrack_free(conntrack
);
492 DEBUGP("init conntrack: can't track with proto module\n");
496 write_lock_bh(&nf_conntrack_lock
);
497 exp
= nf_ct_find_expectation(tuple
);
499 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
501 /* Welcome, Mr. Bond. We've been expecting you... */
502 __set_bit(IPS_EXPECTED_BIT
, &conntrack
->status
);
503 conntrack
->master
= exp
->master
;
505 help
= nf_ct_ext_add(conntrack
, NF_CT_EXT_HELPER
,
508 rcu_assign_pointer(help
->helper
, exp
->helper
);
510 DEBUGP("failed to add helper extension area");
513 #ifdef CONFIG_NF_CONNTRACK_MARK
514 conntrack
->mark
= exp
->master
->mark
;
516 #ifdef CONFIG_NF_CONNTRACK_SECMARK
517 conntrack
->secmark
= exp
->master
->secmark
;
519 nf_conntrack_get(&conntrack
->master
->ct_general
);
520 NF_CT_STAT_INC(expect_new
);
522 struct nf_conntrack_helper
*helper
;
524 helper
= __nf_ct_helper_find(&repl_tuple
);
526 help
= nf_ct_ext_add(conntrack
, NF_CT_EXT_HELPER
,
529 /* not in hash table yet, so not strictly
531 rcu_assign_pointer(help
->helper
, helper
);
533 DEBUGP("failed to add helper extension area");
538 /* Overload tuple linked list to put us in unconfirmed list. */
539 hlist_add_head(&conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
,
542 write_unlock_bh(&nf_conntrack_lock
);
546 exp
->expectfn(conntrack
, exp
);
547 nf_ct_expect_put(exp
);
550 return &conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
];
553 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
554 static inline struct nf_conn
*
555 resolve_normal_ct(struct sk_buff
*skb
,
556 unsigned int dataoff
,
559 struct nf_conntrack_l3proto
*l3proto
,
560 struct nf_conntrack_l4proto
*l4proto
,
562 enum ip_conntrack_info
*ctinfo
)
564 struct nf_conntrack_tuple tuple
;
565 struct nf_conntrack_tuple_hash
*h
;
568 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
),
569 dataoff
, l3num
, protonum
, &tuple
, l3proto
,
571 DEBUGP("resolve_normal_ct: Can't get tuple\n");
575 /* look for tuple match */
576 h
= nf_conntrack_find_get(&tuple
);
578 h
= init_conntrack(&tuple
, l3proto
, l4proto
, skb
, dataoff
);
584 ct
= nf_ct_tuplehash_to_ctrack(h
);
586 /* It exists; we have (non-exclusive) reference. */
587 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
) {
588 *ctinfo
= IP_CT_ESTABLISHED
+ IP_CT_IS_REPLY
;
589 /* Please set reply bit if this packet OK */
592 /* Once we've had two way comms, always ESTABLISHED. */
593 if (test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
594 DEBUGP("nf_conntrack_in: normal packet for %p\n", ct
);
595 *ctinfo
= IP_CT_ESTABLISHED
;
596 } else if (test_bit(IPS_EXPECTED_BIT
, &ct
->status
)) {
597 DEBUGP("nf_conntrack_in: related packet for %p\n", ct
);
598 *ctinfo
= IP_CT_RELATED
;
600 DEBUGP("nf_conntrack_in: new packet for %p\n", ct
);
605 skb
->nfct
= &ct
->ct_general
;
606 skb
->nfctinfo
= *ctinfo
;
611 nf_conntrack_in(int pf
, unsigned int hooknum
, struct sk_buff
**pskb
)
614 enum ip_conntrack_info ctinfo
;
615 struct nf_conntrack_l3proto
*l3proto
;
616 struct nf_conntrack_l4proto
*l4proto
;
617 unsigned int dataoff
;
622 /* Previously seen (loopback or untracked)? Ignore. */
624 NF_CT_STAT_INC_ATOMIC(ignore
);
628 /* rcu_read_lock()ed by nf_hook_slow */
629 l3proto
= __nf_ct_l3proto_find((u_int16_t
)pf
);
631 if ((ret
= l3proto
->prepare(pskb
, hooknum
, &dataoff
, &protonum
)) <= 0) {
632 DEBUGP("not prepared to track yet or error occured\n");
636 l4proto
= __nf_ct_l4proto_find((u_int16_t
)pf
, protonum
);
638 /* It may be an special packet, error, unclean...
639 * inverse of the return code tells to the netfilter
640 * core what to do with the packet. */
641 if (l4proto
->error
!= NULL
&&
642 (ret
= l4proto
->error(*pskb
, dataoff
, &ctinfo
, pf
, hooknum
)) <= 0) {
643 NF_CT_STAT_INC_ATOMIC(error
);
644 NF_CT_STAT_INC_ATOMIC(invalid
);
648 ct
= resolve_normal_ct(*pskb
, dataoff
, pf
, protonum
, l3proto
, l4proto
,
649 &set_reply
, &ctinfo
);
651 /* Not valid part of a connection */
652 NF_CT_STAT_INC_ATOMIC(invalid
);
657 /* Too stressed to deal. */
658 NF_CT_STAT_INC_ATOMIC(drop
);
662 NF_CT_ASSERT((*pskb
)->nfct
);
664 ret
= l4proto
->packet(ct
, *pskb
, dataoff
, ctinfo
, pf
, hooknum
);
666 /* Invalid: inverse of the return code tells
667 * the netfilter core what to do */
668 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
669 nf_conntrack_put((*pskb
)->nfct
);
670 (*pskb
)->nfct
= NULL
;
671 NF_CT_STAT_INC_ATOMIC(invalid
);
675 if (set_reply
&& !test_and_set_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
))
676 nf_conntrack_event_cache(IPCT_STATUS
, *pskb
);
680 EXPORT_SYMBOL_GPL(nf_conntrack_in
);
682 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple
*inverse
,
683 const struct nf_conntrack_tuple
*orig
)
688 ret
= nf_ct_invert_tuple(inverse
, orig
,
689 __nf_ct_l3proto_find(orig
->src
.l3num
),
690 __nf_ct_l4proto_find(orig
->src
.l3num
,
691 orig
->dst
.protonum
));
695 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr
);
697 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
698 implicitly racy: see __nf_conntrack_confirm */
699 void nf_conntrack_alter_reply(struct nf_conn
*ct
,
700 const struct nf_conntrack_tuple
*newreply
)
702 struct nf_conn_help
*help
= nfct_help(ct
);
703 struct nf_conntrack_helper
*helper
;
705 write_lock_bh(&nf_conntrack_lock
);
706 /* Should be unconfirmed, so not in hash table yet */
707 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
709 DEBUGP("Altering reply tuple of %p to ", ct
);
710 NF_CT_DUMP_TUPLE(newreply
);
712 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *newreply
;
713 if (ct
->master
|| (help
&& help
->expecting
!= 0))
716 helper
= __nf_ct_helper_find(newreply
);
717 if (helper
== NULL
) {
719 rcu_assign_pointer(help
->helper
, NULL
);
724 help
= nf_ct_ext_add(ct
, NF_CT_EXT_HELPER
, GFP_ATOMIC
);
726 DEBUGP("failed to add helper extension area");
730 memset(&help
->help
, 0, sizeof(help
->help
));
733 rcu_assign_pointer(help
->helper
, helper
);
735 write_unlock_bh(&nf_conntrack_lock
);
737 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply
);
739 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
740 void __nf_ct_refresh_acct(struct nf_conn
*ct
,
741 enum ip_conntrack_info ctinfo
,
742 const struct sk_buff
*skb
,
743 unsigned long extra_jiffies
,
748 NF_CT_ASSERT(ct
->timeout
.data
== (unsigned long)ct
);
751 write_lock_bh(&nf_conntrack_lock
);
753 /* Only update if this is not a fixed timeout */
754 if (test_bit(IPS_FIXED_TIMEOUT_BIT
, &ct
->status
)) {
755 write_unlock_bh(&nf_conntrack_lock
);
759 /* If not in hash table, timer will not be active yet */
760 if (!nf_ct_is_confirmed(ct
)) {
761 ct
->timeout
.expires
= extra_jiffies
;
762 event
= IPCT_REFRESH
;
764 unsigned long newtime
= jiffies
+ extra_jiffies
;
766 /* Only update the timeout if the new timeout is at least
767 HZ jiffies from the old timeout. Need del_timer for race
768 avoidance (may already be dying). */
769 if (newtime
- ct
->timeout
.expires
>= HZ
770 && del_timer(&ct
->timeout
)) {
771 ct
->timeout
.expires
= newtime
;
772 add_timer(&ct
->timeout
);
773 event
= IPCT_REFRESH
;
777 #ifdef CONFIG_NF_CT_ACCT
779 ct
->counters
[CTINFO2DIR(ctinfo
)].packets
++;
780 ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
+=
781 skb
->len
- skb_network_offset(skb
);
783 if ((ct
->counters
[CTINFO2DIR(ctinfo
)].packets
& 0x80000000)
784 || (ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
& 0x80000000))
785 event
|= IPCT_COUNTER_FILLING
;
789 write_unlock_bh(&nf_conntrack_lock
);
791 /* must be unlocked when calling event cache */
793 nf_conntrack_event_cache(event
, skb
);
795 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct
);
797 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
799 #include <linux/netfilter/nfnetlink.h>
800 #include <linux/netfilter/nfnetlink_conntrack.h>
801 #include <linux/mutex.h>
804 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
805 * in ip_conntrack_core, since we don't want the protocols to autoload
806 * or depend on ctnetlink */
807 int nf_ct_port_tuple_to_nfattr(struct sk_buff
*skb
,
808 const struct nf_conntrack_tuple
*tuple
)
810 NFA_PUT(skb
, CTA_PROTO_SRC_PORT
, sizeof(u_int16_t
),
811 &tuple
->src
.u
.tcp
.port
);
812 NFA_PUT(skb
, CTA_PROTO_DST_PORT
, sizeof(u_int16_t
),
813 &tuple
->dst
.u
.tcp
.port
);
819 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr
);
821 static const size_t cta_min_proto
[CTA_PROTO_MAX
] = {
822 [CTA_PROTO_SRC_PORT
-1] = sizeof(u_int16_t
),
823 [CTA_PROTO_DST_PORT
-1] = sizeof(u_int16_t
)
826 int nf_ct_port_nfattr_to_tuple(struct nfattr
*tb
[],
827 struct nf_conntrack_tuple
*t
)
829 if (!tb
[CTA_PROTO_SRC_PORT
-1] || !tb
[CTA_PROTO_DST_PORT
-1])
832 if (nfattr_bad_size(tb
, CTA_PROTO_MAX
, cta_min_proto
))
835 t
->src
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_SRC_PORT
-1]);
836 t
->dst
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_DST_PORT
-1]);
840 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple
);
843 /* Used by ipt_REJECT and ip6t_REJECT. */
844 void __nf_conntrack_attach(struct sk_buff
*nskb
, struct sk_buff
*skb
)
847 enum ip_conntrack_info ctinfo
;
849 /* This ICMP is in reverse direction to the packet which caused it */
850 ct
= nf_ct_get(skb
, &ctinfo
);
851 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
)
852 ctinfo
= IP_CT_RELATED
+ IP_CT_IS_REPLY
;
854 ctinfo
= IP_CT_RELATED
;
856 /* Attach to new skbuff, and increment count */
857 nskb
->nfct
= &ct
->ct_general
;
858 nskb
->nfctinfo
= ctinfo
;
859 nf_conntrack_get(nskb
->nfct
);
861 EXPORT_SYMBOL_GPL(__nf_conntrack_attach
);
864 do_iter(const struct nf_conntrack_tuple_hash
*i
,
865 int (*iter
)(struct nf_conn
*i
, void *data
),
868 return iter(nf_ct_tuplehash_to_ctrack(i
), data
);
871 /* Bring out ya dead! */
872 static struct nf_conn
*
873 get_next_corpse(int (*iter
)(struct nf_conn
*i
, void *data
),
874 void *data
, unsigned int *bucket
)
876 struct nf_conntrack_tuple_hash
*h
;
878 struct hlist_node
*n
;
880 write_lock_bh(&nf_conntrack_lock
);
881 for (; *bucket
< nf_conntrack_htable_size
; (*bucket
)++) {
882 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[*bucket
], hnode
) {
883 ct
= nf_ct_tuplehash_to_ctrack(h
);
888 hlist_for_each_entry(h
, n
, &unconfirmed
, hnode
) {
889 ct
= nf_ct_tuplehash_to_ctrack(h
);
891 set_bit(IPS_DYING_BIT
, &ct
->status
);
893 write_unlock_bh(&nf_conntrack_lock
);
896 atomic_inc(&ct
->ct_general
.use
);
897 write_unlock_bh(&nf_conntrack_lock
);
902 nf_ct_iterate_cleanup(int (*iter
)(struct nf_conn
*i
, void *data
), void *data
)
905 unsigned int bucket
= 0;
907 while ((ct
= get_next_corpse(iter
, data
, &bucket
)) != NULL
) {
908 /* Time to push up daises... */
909 if (del_timer(&ct
->timeout
))
910 death_by_timeout((unsigned long)ct
);
911 /* ... else the timer will get him soon. */
916 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup
);
918 static int kill_all(struct nf_conn
*i
, void *data
)
923 void nf_ct_free_hashtable(struct hlist_head
*hash
, int vmalloced
, int size
)
928 free_pages((unsigned long)hash
,
929 get_order(sizeof(struct hlist_head
) * size
));
931 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable
);
933 void nf_conntrack_flush(void)
935 nf_ct_iterate_cleanup(kill_all
, NULL
);
937 EXPORT_SYMBOL_GPL(nf_conntrack_flush
);
939 /* Mishearing the voices in his head, our hero wonders how he's
940 supposed to kill the mall. */
941 void nf_conntrack_cleanup(void)
943 rcu_assign_pointer(ip_ct_attach
, NULL
);
945 /* This makes sure all current packets have passed through
946 netfilter framework. Roll on, two-stage module
950 nf_ct_event_cache_flush();
952 nf_conntrack_flush();
953 if (atomic_read(&nf_conntrack_count
) != 0) {
955 goto i_see_dead_people
;
957 /* wait until all references to nf_conntrack_untracked are dropped */
958 while (atomic_read(&nf_conntrack_untracked
.ct_general
.use
) > 1)
961 rcu_assign_pointer(nf_ct_destroy
, NULL
);
963 kmem_cache_destroy(nf_conntrack_cachep
);
964 nf_ct_free_hashtable(nf_conntrack_hash
, nf_conntrack_vmalloc
,
965 nf_conntrack_htable_size
);
967 nf_conntrack_proto_fini();
968 nf_conntrack_helper_fini();
969 nf_conntrack_expect_fini();
972 struct hlist_head
*nf_ct_alloc_hashtable(int *sizep
, int *vmalloced
)
974 struct hlist_head
*hash
;
975 unsigned int size
, i
;
979 size
= *sizep
= roundup(*sizep
, PAGE_SIZE
/ sizeof(struct hlist_head
));
980 hash
= (void*)__get_free_pages(GFP_KERNEL
,
981 get_order(sizeof(struct hlist_head
)
985 printk(KERN_WARNING
"nf_conntrack: falling back to vmalloc.\n");
986 hash
= vmalloc(sizeof(struct hlist_head
) * size
);
990 for (i
= 0; i
< size
; i
++)
991 INIT_HLIST_HEAD(&hash
[i
]);
995 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable
);
997 int set_hashsize(const char *val
, struct kernel_param
*kp
)
999 int i
, bucket
, hashsize
, vmalloced
;
1000 int old_vmalloced
, old_size
;
1002 struct hlist_head
*hash
, *old_hash
;
1003 struct nf_conntrack_tuple_hash
*h
;
1005 /* On boot, we can set this without any fancy locking. */
1006 if (!nf_conntrack_htable_size
)
1007 return param_set_uint(val
, kp
);
1009 hashsize
= simple_strtol(val
, NULL
, 0);
1013 hash
= nf_ct_alloc_hashtable(&hashsize
, &vmalloced
);
1017 /* We have to rehahs for the new table anyway, so we also can
1018 * use a newrandom seed */
1019 get_random_bytes(&rnd
, 4);
1021 write_lock_bh(&nf_conntrack_lock
);
1022 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
1023 while (!hlist_empty(&nf_conntrack_hash
[i
])) {
1024 h
= hlist_entry(nf_conntrack_hash
[i
].first
,
1025 struct nf_conntrack_tuple_hash
, hnode
);
1026 hlist_del(&h
->hnode
);
1027 bucket
= __hash_conntrack(&h
->tuple
, hashsize
, rnd
);
1028 hlist_add_head(&h
->hnode
, &hash
[bucket
]);
1031 old_size
= nf_conntrack_htable_size
;
1032 old_vmalloced
= nf_conntrack_vmalloc
;
1033 old_hash
= nf_conntrack_hash
;
1035 nf_conntrack_htable_size
= hashsize
;
1036 nf_conntrack_vmalloc
= vmalloced
;
1037 nf_conntrack_hash
= hash
;
1038 nf_conntrack_hash_rnd
= rnd
;
1039 write_unlock_bh(&nf_conntrack_lock
);
1041 nf_ct_free_hashtable(old_hash
, old_vmalloced
, old_size
);
1045 module_param_call(hashsize
, set_hashsize
, param_get_uint
,
1046 &nf_conntrack_htable_size
, 0600);
1048 int __init
nf_conntrack_init(void)
1053 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1054 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1055 if (!nf_conntrack_htable_size
) {
1056 nf_conntrack_htable_size
1057 = (((num_physpages
<< PAGE_SHIFT
) / 16384)
1058 / sizeof(struct hlist_head
));
1059 if (num_physpages
> (1024 * 1024 * 1024 / PAGE_SIZE
))
1060 nf_conntrack_htable_size
= 16384;
1061 if (nf_conntrack_htable_size
< 32)
1062 nf_conntrack_htable_size
= 32;
1064 /* Use a max. factor of four by default to get the same max as
1065 * with the old struct list_heads. When a table size is given
1066 * we use the old value of 8 to avoid reducing the max.
1070 nf_conntrack_hash
= nf_ct_alloc_hashtable(&nf_conntrack_htable_size
,
1071 &nf_conntrack_vmalloc
);
1072 if (!nf_conntrack_hash
) {
1073 printk(KERN_ERR
"Unable to create nf_conntrack_hash\n");
1077 nf_conntrack_max
= max_factor
* nf_conntrack_htable_size
;
1079 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1080 NF_CONNTRACK_VERSION
, nf_conntrack_htable_size
,
1083 nf_conntrack_cachep
= kmem_cache_create("nf_conntrack",
1084 sizeof(struct nf_conn
),
1086 if (!nf_conntrack_cachep
) {
1087 printk(KERN_ERR
"Unable to create nf_conn slab cache\n");
1091 ret
= nf_conntrack_proto_init();
1093 goto err_free_conntrack_slab
;
1095 ret
= nf_conntrack_expect_init();
1097 goto out_fini_proto
;
1099 ret
= nf_conntrack_helper_init();
1101 goto out_fini_expect
;
1103 /* For use by REJECT target */
1104 rcu_assign_pointer(ip_ct_attach
, __nf_conntrack_attach
);
1105 rcu_assign_pointer(nf_ct_destroy
, destroy_conntrack
);
1107 /* Set up fake conntrack:
1108 - to never be deleted, not in any hashes */
1109 atomic_set(&nf_conntrack_untracked
.ct_general
.use
, 1);
1110 /* - and look it like as a confirmed connection */
1111 set_bit(IPS_CONFIRMED_BIT
, &nf_conntrack_untracked
.status
);
1116 nf_conntrack_expect_fini();
1118 nf_conntrack_proto_fini();
1119 err_free_conntrack_slab
:
1120 kmem_cache_destroy(nf_conntrack_cachep
);
1122 nf_ct_free_hashtable(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1123 nf_conntrack_htable_size
);