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
;
74 static struct kmem_cache
*nf_conntrack_cachep __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
);
80 static int nf_conntrack_hash_rnd_initted
;
81 static unsigned int nf_conntrack_hash_rnd
;
83 static u_int32_t
__hash_conntrack(const struct nf_conntrack_tuple
*tuple
,
84 unsigned int size
, unsigned int rnd
)
88 a
= jhash2(tuple
->src
.u3
.all
, ARRAY_SIZE(tuple
->src
.u3
.all
),
89 (tuple
->src
.l3num
<< 16) | tuple
->dst
.protonum
);
90 b
= jhash2(tuple
->dst
.u3
.all
, ARRAY_SIZE(tuple
->dst
.u3
.all
),
91 (tuple
->src
.u
.all
<< 16) | tuple
->dst
.u
.all
);
93 return jhash_2words(a
, b
, rnd
) % size
;
96 static inline u_int32_t
hash_conntrack(const struct nf_conntrack_tuple
*tuple
)
98 return __hash_conntrack(tuple
, nf_conntrack_htable_size
,
99 nf_conntrack_hash_rnd
);
103 nf_ct_get_tuple(const struct sk_buff
*skb
,
105 unsigned int dataoff
,
108 struct nf_conntrack_tuple
*tuple
,
109 const struct nf_conntrack_l3proto
*l3proto
,
110 const struct nf_conntrack_l4proto
*l4proto
)
112 NF_CT_TUPLE_U_BLANK(tuple
);
114 tuple
->src
.l3num
= l3num
;
115 if (l3proto
->pkt_to_tuple(skb
, nhoff
, tuple
) == 0)
118 tuple
->dst
.protonum
= protonum
;
119 tuple
->dst
.dir
= IP_CT_DIR_ORIGINAL
;
121 return l4proto
->pkt_to_tuple(skb
, dataoff
, tuple
);
123 EXPORT_SYMBOL_GPL(nf_ct_get_tuple
);
126 nf_ct_invert_tuple(struct nf_conntrack_tuple
*inverse
,
127 const struct nf_conntrack_tuple
*orig
,
128 const struct nf_conntrack_l3proto
*l3proto
,
129 const struct nf_conntrack_l4proto
*l4proto
)
131 NF_CT_TUPLE_U_BLANK(inverse
);
133 inverse
->src
.l3num
= orig
->src
.l3num
;
134 if (l3proto
->invert_tuple(inverse
, orig
) == 0)
137 inverse
->dst
.dir
= !orig
->dst
.dir
;
139 inverse
->dst
.protonum
= orig
->dst
.protonum
;
140 return l4proto
->invert_tuple(inverse
, orig
);
142 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple
);
145 clean_from_lists(struct nf_conn
*ct
)
147 DEBUGP("clean_from_lists(%p)\n", ct
);
148 list_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
);
149 list_del(&ct
->tuplehash
[IP_CT_DIR_REPLY
].list
);
151 /* Destroy all pending expectations */
152 nf_ct_remove_expectations(ct
);
156 destroy_conntrack(struct nf_conntrack
*nfct
)
158 struct nf_conn
*ct
= (struct nf_conn
*)nfct
;
159 struct nf_conntrack_l4proto
*l4proto
;
160 typeof(nf_conntrack_destroyed
) destroyed
;
162 DEBUGP("destroy_conntrack(%p)\n", ct
);
163 NF_CT_ASSERT(atomic_read(&nfct
->use
) == 0);
164 NF_CT_ASSERT(!timer_pending(&ct
->timeout
));
166 nf_conntrack_event(IPCT_DESTROY
, ct
);
167 set_bit(IPS_DYING_BIT
, &ct
->status
);
169 /* To make sure we don't get any weird locking issues here:
170 * destroy_conntrack() MUST NOT be called with a write lock
171 * to nf_conntrack_lock!!! -HW */
173 l4proto
= __nf_ct_l4proto_find(ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.src
.l3num
,
174 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.protonum
);
175 if (l4proto
&& l4proto
->destroy
)
176 l4proto
->destroy(ct
);
178 nf_ct_ext_destroy(ct
);
180 destroyed
= rcu_dereference(nf_conntrack_destroyed
);
186 write_lock_bh(&nf_conntrack_lock
);
187 /* Expectations will have been removed in clean_from_lists,
188 * except TFTP can create an expectation on the first packet,
189 * before connection is in the list, so we need to clean here,
191 nf_ct_remove_expectations(ct
);
193 /* We overload first tuple to link into unconfirmed list. */
194 if (!nf_ct_is_confirmed(ct
)) {
195 BUG_ON(list_empty(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
));
196 list_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
);
199 NF_CT_STAT_INC(delete);
200 write_unlock_bh(&nf_conntrack_lock
);
203 nf_ct_put(ct
->master
);
205 DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct
);
206 nf_conntrack_free(ct
);
209 static void death_by_timeout(unsigned long ul_conntrack
)
211 struct nf_conn
*ct
= (void *)ul_conntrack
;
212 struct nf_conn_help
*help
= nfct_help(ct
);
213 struct nf_conntrack_helper
*helper
;
217 helper
= rcu_dereference(help
->helper
);
218 if (helper
&& helper
->destroy
)
223 write_lock_bh(&nf_conntrack_lock
);
224 /* Inside lock so preempt is disabled on module removal path.
225 * Otherwise we can get spurious warnings. */
226 NF_CT_STAT_INC(delete_list
);
227 clean_from_lists(ct
);
228 write_unlock_bh(&nf_conntrack_lock
);
232 struct nf_conntrack_tuple_hash
*
233 __nf_conntrack_find(const struct nf_conntrack_tuple
*tuple
,
234 const struct nf_conn
*ignored_conntrack
)
236 struct nf_conntrack_tuple_hash
*h
;
237 unsigned int hash
= hash_conntrack(tuple
);
239 list_for_each_entry(h
, &nf_conntrack_hash
[hash
], list
) {
240 if (nf_ct_tuplehash_to_ctrack(h
) != ignored_conntrack
&&
241 nf_ct_tuple_equal(tuple
, &h
->tuple
)) {
242 NF_CT_STAT_INC(found
);
245 NF_CT_STAT_INC(searched
);
250 EXPORT_SYMBOL_GPL(__nf_conntrack_find
);
252 /* Find a connection corresponding to a tuple. */
253 struct nf_conntrack_tuple_hash
*
254 nf_conntrack_find_get(const struct nf_conntrack_tuple
*tuple
,
255 const struct nf_conn
*ignored_conntrack
)
257 struct nf_conntrack_tuple_hash
*h
;
259 read_lock_bh(&nf_conntrack_lock
);
260 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
262 atomic_inc(&nf_ct_tuplehash_to_ctrack(h
)->ct_general
.use
);
263 read_unlock_bh(&nf_conntrack_lock
);
267 EXPORT_SYMBOL_GPL(nf_conntrack_find_get
);
269 static void __nf_conntrack_hash_insert(struct nf_conn
*ct
,
271 unsigned int repl_hash
)
273 ct
->id
= ++nf_conntrack_next_id
;
274 list_add(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
,
275 &nf_conntrack_hash
[hash
]);
276 list_add(&ct
->tuplehash
[IP_CT_DIR_REPLY
].list
,
277 &nf_conntrack_hash
[repl_hash
]);
280 void nf_conntrack_hash_insert(struct nf_conn
*ct
)
282 unsigned int hash
, repl_hash
;
284 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
285 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
287 write_lock_bh(&nf_conntrack_lock
);
288 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
289 write_unlock_bh(&nf_conntrack_lock
);
291 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert
);
293 /* Confirm a connection given skb; places it in hash table */
295 __nf_conntrack_confirm(struct sk_buff
**pskb
)
297 unsigned int hash
, repl_hash
;
298 struct nf_conntrack_tuple_hash
*h
;
300 struct nf_conn_help
*help
;
301 enum ip_conntrack_info ctinfo
;
303 ct
= nf_ct_get(*pskb
, &ctinfo
);
305 /* ipt_REJECT uses nf_conntrack_attach to attach related
306 ICMP/TCP RST packets in other direction. Actual packet
307 which created connection will be IP_CT_NEW or for an
308 expected connection, IP_CT_RELATED. */
309 if (CTINFO2DIR(ctinfo
) != IP_CT_DIR_ORIGINAL
)
312 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
313 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
315 /* We're not in hash table, and we refuse to set up related
316 connections for unconfirmed conns. But packet copies and
317 REJECT will give spurious warnings here. */
318 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
320 /* No external references means noone else could have
322 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
323 DEBUGP("Confirming conntrack %p\n", ct
);
325 write_lock_bh(&nf_conntrack_lock
);
327 /* See if there's one in the list already, including reverse:
328 NAT could have grabbed it without realizing, since we're
329 not in the hash. If there is, we lost race. */
330 list_for_each_entry(h
, &nf_conntrack_hash
[hash
], list
)
331 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
334 list_for_each_entry(h
, &nf_conntrack_hash
[repl_hash
], list
)
335 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
339 /* Remove from unconfirmed list */
340 list_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
);
342 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
343 /* Timer relative to confirmation time, not original
344 setting time, otherwise we'd get timer wrap in
345 weird delay cases. */
346 ct
->timeout
.expires
+= jiffies
;
347 add_timer(&ct
->timeout
);
348 atomic_inc(&ct
->ct_general
.use
);
349 set_bit(IPS_CONFIRMED_BIT
, &ct
->status
);
350 NF_CT_STAT_INC(insert
);
351 write_unlock_bh(&nf_conntrack_lock
);
352 help
= nfct_help(ct
);
353 if (help
&& help
->helper
)
354 nf_conntrack_event_cache(IPCT_HELPER
, *pskb
);
355 #ifdef CONFIG_NF_NAT_NEEDED
356 if (test_bit(IPS_SRC_NAT_DONE_BIT
, &ct
->status
) ||
357 test_bit(IPS_DST_NAT_DONE_BIT
, &ct
->status
))
358 nf_conntrack_event_cache(IPCT_NATINFO
, *pskb
);
360 nf_conntrack_event_cache(master_ct(ct
) ?
361 IPCT_RELATED
: IPCT_NEW
, *pskb
);
365 NF_CT_STAT_INC(insert_failed
);
366 write_unlock_bh(&nf_conntrack_lock
);
369 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm
);
371 /* Returns true if a connection correspondings to the tuple (required
374 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple
*tuple
,
375 const struct nf_conn
*ignored_conntrack
)
377 struct nf_conntrack_tuple_hash
*h
;
379 read_lock_bh(&nf_conntrack_lock
);
380 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
381 read_unlock_bh(&nf_conntrack_lock
);
385 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken
);
387 /* There's a small race here where we may free a just-assured
388 connection. Too bad: we're in trouble anyway. */
389 static int early_drop(struct list_head
*chain
)
391 /* Traverse backwards: gives us oldest, which is roughly LRU */
392 struct nf_conntrack_tuple_hash
*h
;
393 struct nf_conn
*ct
= NULL
, *tmp
;
396 read_lock_bh(&nf_conntrack_lock
);
397 list_for_each_entry_reverse(h
, chain
, list
) {
398 tmp
= nf_ct_tuplehash_to_ctrack(h
);
399 if (!test_bit(IPS_ASSURED_BIT
, &tmp
->status
)) {
401 atomic_inc(&ct
->ct_general
.use
);
405 read_unlock_bh(&nf_conntrack_lock
);
410 if (del_timer(&ct
->timeout
)) {
411 death_by_timeout((unsigned long)ct
);
413 NF_CT_STAT_INC_ATOMIC(early_drop
);
419 struct nf_conn
*nf_conntrack_alloc(const struct nf_conntrack_tuple
*orig
,
420 const struct nf_conntrack_tuple
*repl
)
422 struct nf_conn
*conntrack
= NULL
;
424 if (unlikely(!nf_conntrack_hash_rnd_initted
)) {
425 get_random_bytes(&nf_conntrack_hash_rnd
, 4);
426 nf_conntrack_hash_rnd_initted
= 1;
429 /* We don't want any race condition at early drop stage */
430 atomic_inc(&nf_conntrack_count
);
433 && atomic_read(&nf_conntrack_count
) > nf_conntrack_max
) {
434 unsigned int hash
= hash_conntrack(orig
);
435 /* Try dropping from this hash chain. */
436 if (!early_drop(&nf_conntrack_hash
[hash
])) {
437 atomic_dec(&nf_conntrack_count
);
440 "nf_conntrack: table full, dropping"
442 return ERR_PTR(-ENOMEM
);
446 conntrack
= kmem_cache_zalloc(nf_conntrack_cachep
, GFP_ATOMIC
);
447 if (conntrack
== NULL
) {
448 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack.\n");
449 atomic_dec(&nf_conntrack_count
);
450 return ERR_PTR(-ENOMEM
);
453 atomic_set(&conntrack
->ct_general
.use
, 1);
454 conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
= *orig
;
455 conntrack
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *repl
;
456 /* Don't set timer yet: wait for confirmation */
457 setup_timer(&conntrack
->timeout
, death_by_timeout
,
458 (unsigned long)conntrack
);
462 EXPORT_SYMBOL_GPL(nf_conntrack_alloc
);
464 void nf_conntrack_free(struct nf_conn
*conntrack
)
466 nf_ct_ext_free(conntrack
);
467 kmem_cache_free(nf_conntrack_cachep
, conntrack
);
468 atomic_dec(&nf_conntrack_count
);
470 EXPORT_SYMBOL_GPL(nf_conntrack_free
);
472 /* Allocate a new conntrack: we return -ENOMEM if classification
473 failed due to stress. Otherwise it really is unclassifiable. */
474 static struct nf_conntrack_tuple_hash
*
475 init_conntrack(const struct nf_conntrack_tuple
*tuple
,
476 struct nf_conntrack_l3proto
*l3proto
,
477 struct nf_conntrack_l4proto
*l4proto
,
479 unsigned int dataoff
)
481 struct nf_conn
*conntrack
;
482 struct nf_conn_help
*help
;
483 struct nf_conntrack_tuple repl_tuple
;
484 struct nf_conntrack_expect
*exp
;
486 if (!nf_ct_invert_tuple(&repl_tuple
, tuple
, l3proto
, l4proto
)) {
487 DEBUGP("Can't invert tuple.\n");
491 conntrack
= nf_conntrack_alloc(tuple
, &repl_tuple
);
492 if (conntrack
== NULL
|| IS_ERR(conntrack
)) {
493 DEBUGP("Can't allocate conntrack.\n");
494 return (struct nf_conntrack_tuple_hash
*)conntrack
;
497 if (!l4proto
->new(conntrack
, skb
, dataoff
)) {
498 nf_conntrack_free(conntrack
);
499 DEBUGP("init conntrack: can't track with proto module\n");
503 write_lock_bh(&nf_conntrack_lock
);
504 exp
= find_expectation(tuple
);
506 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
508 /* Welcome, Mr. Bond. We've been expecting you... */
509 __set_bit(IPS_EXPECTED_BIT
, &conntrack
->status
);
510 conntrack
->master
= exp
->master
;
512 help
= nf_ct_ext_add(conntrack
, NF_CT_EXT_HELPER
,
515 rcu_assign_pointer(help
->helper
, exp
->helper
);
517 DEBUGP("failed to add helper extension area");
520 #ifdef CONFIG_NF_CONNTRACK_MARK
521 conntrack
->mark
= exp
->master
->mark
;
523 #ifdef CONFIG_NF_CONNTRACK_SECMARK
524 conntrack
->secmark
= exp
->master
->secmark
;
526 nf_conntrack_get(&conntrack
->master
->ct_general
);
527 NF_CT_STAT_INC(expect_new
);
529 struct nf_conntrack_helper
*helper
;
531 helper
= __nf_ct_helper_find(&repl_tuple
);
533 help
= nf_ct_ext_add(conntrack
, NF_CT_EXT_HELPER
,
536 /* not in hash table yet, so not strictly
538 rcu_assign_pointer(help
->helper
, helper
);
540 DEBUGP("failed to add helper extension area");
545 /* Overload tuple linked list to put us in unconfirmed list. */
546 list_add(&conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].list
, &unconfirmed
);
548 write_unlock_bh(&nf_conntrack_lock
);
552 exp
->expectfn(conntrack
, exp
);
553 nf_conntrack_expect_put(exp
);
556 return &conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
];
559 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
560 static inline struct nf_conn
*
561 resolve_normal_ct(struct sk_buff
*skb
,
562 unsigned int dataoff
,
565 struct nf_conntrack_l3proto
*l3proto
,
566 struct nf_conntrack_l4proto
*l4proto
,
568 enum ip_conntrack_info
*ctinfo
)
570 struct nf_conntrack_tuple tuple
;
571 struct nf_conntrack_tuple_hash
*h
;
574 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
),
575 dataoff
, l3num
, protonum
, &tuple
, l3proto
,
577 DEBUGP("resolve_normal_ct: Can't get tuple\n");
581 /* look for tuple match */
582 h
= nf_conntrack_find_get(&tuple
, NULL
);
584 h
= init_conntrack(&tuple
, l3proto
, l4proto
, skb
, dataoff
);
590 ct
= nf_ct_tuplehash_to_ctrack(h
);
592 /* It exists; we have (non-exclusive) reference. */
593 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
) {
594 *ctinfo
= IP_CT_ESTABLISHED
+ IP_CT_IS_REPLY
;
595 /* Please set reply bit if this packet OK */
598 /* Once we've had two way comms, always ESTABLISHED. */
599 if (test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
600 DEBUGP("nf_conntrack_in: normal packet for %p\n", ct
);
601 *ctinfo
= IP_CT_ESTABLISHED
;
602 } else if (test_bit(IPS_EXPECTED_BIT
, &ct
->status
)) {
603 DEBUGP("nf_conntrack_in: related packet for %p\n", ct
);
604 *ctinfo
= IP_CT_RELATED
;
606 DEBUGP("nf_conntrack_in: new packet for %p\n", ct
);
611 skb
->nfct
= &ct
->ct_general
;
612 skb
->nfctinfo
= *ctinfo
;
617 nf_conntrack_in(int pf
, unsigned int hooknum
, struct sk_buff
**pskb
)
620 enum ip_conntrack_info ctinfo
;
621 struct nf_conntrack_l3proto
*l3proto
;
622 struct nf_conntrack_l4proto
*l4proto
;
623 unsigned int dataoff
;
628 /* Previously seen (loopback or untracked)? Ignore. */
630 NF_CT_STAT_INC_ATOMIC(ignore
);
634 /* rcu_read_lock()ed by nf_hook_slow */
635 l3proto
= __nf_ct_l3proto_find((u_int16_t
)pf
);
637 if ((ret
= l3proto
->prepare(pskb
, hooknum
, &dataoff
, &protonum
)) <= 0) {
638 DEBUGP("not prepared to track yet or error occured\n");
642 l4proto
= __nf_ct_l4proto_find((u_int16_t
)pf
, protonum
);
644 /* It may be an special packet, error, unclean...
645 * inverse of the return code tells to the netfilter
646 * core what to do with the packet. */
647 if (l4proto
->error
!= NULL
&&
648 (ret
= l4proto
->error(*pskb
, dataoff
, &ctinfo
, pf
, hooknum
)) <= 0) {
649 NF_CT_STAT_INC_ATOMIC(error
);
650 NF_CT_STAT_INC_ATOMIC(invalid
);
654 ct
= resolve_normal_ct(*pskb
, dataoff
, pf
, protonum
, l3proto
, l4proto
,
655 &set_reply
, &ctinfo
);
657 /* Not valid part of a connection */
658 NF_CT_STAT_INC_ATOMIC(invalid
);
663 /* Too stressed to deal. */
664 NF_CT_STAT_INC_ATOMIC(drop
);
668 NF_CT_ASSERT((*pskb
)->nfct
);
670 ret
= l4proto
->packet(ct
, *pskb
, dataoff
, ctinfo
, pf
, hooknum
);
672 /* Invalid: inverse of the return code tells
673 * the netfilter core what to do */
674 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
675 nf_conntrack_put((*pskb
)->nfct
);
676 (*pskb
)->nfct
= NULL
;
677 NF_CT_STAT_INC_ATOMIC(invalid
);
681 if (set_reply
&& !test_and_set_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
))
682 nf_conntrack_event_cache(IPCT_STATUS
, *pskb
);
686 EXPORT_SYMBOL_GPL(nf_conntrack_in
);
688 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple
*inverse
,
689 const struct nf_conntrack_tuple
*orig
)
694 ret
= nf_ct_invert_tuple(inverse
, orig
,
695 __nf_ct_l3proto_find(orig
->src
.l3num
),
696 __nf_ct_l4proto_find(orig
->src
.l3num
,
697 orig
->dst
.protonum
));
701 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr
);
703 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
704 implicitly racy: see __nf_conntrack_confirm */
705 void nf_conntrack_alter_reply(struct nf_conn
*ct
,
706 const struct nf_conntrack_tuple
*newreply
)
708 struct nf_conn_help
*help
= nfct_help(ct
);
709 struct nf_conntrack_helper
*helper
;
711 write_lock_bh(&nf_conntrack_lock
);
712 /* Should be unconfirmed, so not in hash table yet */
713 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
715 DEBUGP("Altering reply tuple of %p to ", ct
);
716 NF_CT_DUMP_TUPLE(newreply
);
718 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *newreply
;
719 if (ct
->master
|| (help
&& help
->expecting
!= 0))
722 helper
= __nf_ct_helper_find(newreply
);
723 if (helper
== NULL
) {
725 rcu_assign_pointer(help
->helper
, NULL
);
730 help
= nf_ct_ext_add(ct
, NF_CT_EXT_HELPER
, GFP_ATOMIC
);
732 DEBUGP("failed to add helper extension area");
736 memset(&help
->help
, 0, sizeof(help
->help
));
739 rcu_assign_pointer(help
->helper
, helper
);
741 write_unlock_bh(&nf_conntrack_lock
);
743 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply
);
745 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
746 void __nf_ct_refresh_acct(struct nf_conn
*ct
,
747 enum ip_conntrack_info ctinfo
,
748 const struct sk_buff
*skb
,
749 unsigned long extra_jiffies
,
754 NF_CT_ASSERT(ct
->timeout
.data
== (unsigned long)ct
);
757 write_lock_bh(&nf_conntrack_lock
);
759 /* Only update if this is not a fixed timeout */
760 if (test_bit(IPS_FIXED_TIMEOUT_BIT
, &ct
->status
)) {
761 write_unlock_bh(&nf_conntrack_lock
);
765 /* If not in hash table, timer will not be active yet */
766 if (!nf_ct_is_confirmed(ct
)) {
767 ct
->timeout
.expires
= extra_jiffies
;
768 event
= IPCT_REFRESH
;
770 unsigned long newtime
= jiffies
+ extra_jiffies
;
772 /* Only update the timeout if the new timeout is at least
773 HZ jiffies from the old timeout. Need del_timer for race
774 avoidance (may already be dying). */
775 if (newtime
- ct
->timeout
.expires
>= HZ
776 && del_timer(&ct
->timeout
)) {
777 ct
->timeout
.expires
= newtime
;
778 add_timer(&ct
->timeout
);
779 event
= IPCT_REFRESH
;
783 #ifdef CONFIG_NF_CT_ACCT
785 ct
->counters
[CTINFO2DIR(ctinfo
)].packets
++;
786 ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
+=
787 skb
->len
- skb_network_offset(skb
);
789 if ((ct
->counters
[CTINFO2DIR(ctinfo
)].packets
& 0x80000000)
790 || (ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
& 0x80000000))
791 event
|= IPCT_COUNTER_FILLING
;
795 write_unlock_bh(&nf_conntrack_lock
);
797 /* must be unlocked when calling event cache */
799 nf_conntrack_event_cache(event
, skb
);
801 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct
);
803 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
805 #include <linux/netfilter/nfnetlink.h>
806 #include <linux/netfilter/nfnetlink_conntrack.h>
807 #include <linux/mutex.h>
810 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
811 * in ip_conntrack_core, since we don't want the protocols to autoload
812 * or depend on ctnetlink */
813 int nf_ct_port_tuple_to_nfattr(struct sk_buff
*skb
,
814 const struct nf_conntrack_tuple
*tuple
)
816 NFA_PUT(skb
, CTA_PROTO_SRC_PORT
, sizeof(u_int16_t
),
817 &tuple
->src
.u
.tcp
.port
);
818 NFA_PUT(skb
, CTA_PROTO_DST_PORT
, sizeof(u_int16_t
),
819 &tuple
->dst
.u
.tcp
.port
);
825 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr
);
827 static const size_t cta_min_proto
[CTA_PROTO_MAX
] = {
828 [CTA_PROTO_SRC_PORT
-1] = sizeof(u_int16_t
),
829 [CTA_PROTO_DST_PORT
-1] = sizeof(u_int16_t
)
832 int nf_ct_port_nfattr_to_tuple(struct nfattr
*tb
[],
833 struct nf_conntrack_tuple
*t
)
835 if (!tb
[CTA_PROTO_SRC_PORT
-1] || !tb
[CTA_PROTO_DST_PORT
-1])
838 if (nfattr_bad_size(tb
, CTA_PROTO_MAX
, cta_min_proto
))
841 t
->src
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_SRC_PORT
-1]);
842 t
->dst
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_DST_PORT
-1]);
846 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple
);
849 /* Used by ipt_REJECT and ip6t_REJECT. */
850 void __nf_conntrack_attach(struct sk_buff
*nskb
, struct sk_buff
*skb
)
853 enum ip_conntrack_info ctinfo
;
855 /* This ICMP is in reverse direction to the packet which caused it */
856 ct
= nf_ct_get(skb
, &ctinfo
);
857 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
)
858 ctinfo
= IP_CT_RELATED
+ IP_CT_IS_REPLY
;
860 ctinfo
= IP_CT_RELATED
;
862 /* Attach to new skbuff, and increment count */
863 nskb
->nfct
= &ct
->ct_general
;
864 nskb
->nfctinfo
= ctinfo
;
865 nf_conntrack_get(nskb
->nfct
);
867 EXPORT_SYMBOL_GPL(__nf_conntrack_attach
);
870 do_iter(const struct nf_conntrack_tuple_hash
*i
,
871 int (*iter
)(struct nf_conn
*i
, void *data
),
874 return iter(nf_ct_tuplehash_to_ctrack(i
), data
);
877 /* Bring out ya dead! */
878 static struct nf_conn
*
879 get_next_corpse(int (*iter
)(struct nf_conn
*i
, void *data
),
880 void *data
, unsigned int *bucket
)
882 struct nf_conntrack_tuple_hash
*h
;
885 write_lock_bh(&nf_conntrack_lock
);
886 for (; *bucket
< nf_conntrack_htable_size
; (*bucket
)++) {
887 list_for_each_entry(h
, &nf_conntrack_hash
[*bucket
], list
) {
888 ct
= nf_ct_tuplehash_to_ctrack(h
);
893 list_for_each_entry(h
, &unconfirmed
, list
) {
894 ct
= nf_ct_tuplehash_to_ctrack(h
);
896 set_bit(IPS_DYING_BIT
, &ct
->status
);
898 write_unlock_bh(&nf_conntrack_lock
);
901 atomic_inc(&ct
->ct_general
.use
);
902 write_unlock_bh(&nf_conntrack_lock
);
907 nf_ct_iterate_cleanup(int (*iter
)(struct nf_conn
*i
, void *data
), void *data
)
910 unsigned int bucket
= 0;
912 while ((ct
= get_next_corpse(iter
, data
, &bucket
)) != NULL
) {
913 /* Time to push up daises... */
914 if (del_timer(&ct
->timeout
))
915 death_by_timeout((unsigned long)ct
);
916 /* ... else the timer will get him soon. */
921 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup
);
923 static int kill_all(struct nf_conn
*i
, void *data
)
928 static void free_conntrack_hash(struct list_head
*hash
, int vmalloced
, int size
)
933 free_pages((unsigned long)hash
,
934 get_order(sizeof(struct list_head
) * size
));
937 void nf_conntrack_flush(void)
939 nf_ct_iterate_cleanup(kill_all
, NULL
);
941 EXPORT_SYMBOL_GPL(nf_conntrack_flush
);
943 /* Mishearing the voices in his head, our hero wonders how he's
944 supposed to kill the mall. */
945 void nf_conntrack_cleanup(void)
947 rcu_assign_pointer(ip_ct_attach
, NULL
);
949 /* This makes sure all current packets have passed through
950 netfilter framework. Roll on, two-stage module
954 nf_ct_event_cache_flush();
956 nf_conntrack_flush();
957 if (atomic_read(&nf_conntrack_count
) != 0) {
959 goto i_see_dead_people
;
961 /* wait until all references to nf_conntrack_untracked are dropped */
962 while (atomic_read(&nf_conntrack_untracked
.ct_general
.use
) > 1)
965 rcu_assign_pointer(nf_ct_destroy
, NULL
);
967 kmem_cache_destroy(nf_conntrack_cachep
);
968 kmem_cache_destroy(nf_conntrack_expect_cachep
);
969 free_conntrack_hash(nf_conntrack_hash
, nf_conntrack_vmalloc
,
970 nf_conntrack_htable_size
);
972 nf_conntrack_proto_fini();
973 nf_conntrack_helper_fini();
976 static struct list_head
*alloc_hashtable(int size
, int *vmalloced
)
978 struct list_head
*hash
;
982 hash
= (void*)__get_free_pages(GFP_KERNEL
,
983 get_order(sizeof(struct list_head
)
987 printk(KERN_WARNING
"nf_conntrack: falling back to vmalloc.\n");
988 hash
= vmalloc(sizeof(struct list_head
) * size
);
992 for (i
= 0; i
< size
; i
++)
993 INIT_LIST_HEAD(&hash
[i
]);
998 int set_hashsize(const char *val
, struct kernel_param
*kp
)
1000 int i
, bucket
, hashsize
, vmalloced
;
1001 int old_vmalloced
, old_size
;
1003 struct list_head
*hash
, *old_hash
;
1004 struct nf_conntrack_tuple_hash
*h
;
1006 /* On boot, we can set this without any fancy locking. */
1007 if (!nf_conntrack_htable_size
)
1008 return param_set_uint(val
, kp
);
1010 hashsize
= simple_strtol(val
, NULL
, 0);
1014 hash
= alloc_hashtable(hashsize
, &vmalloced
);
1018 /* We have to rehahs for the new table anyway, so we also can
1019 * use a newrandom seed */
1020 get_random_bytes(&rnd
, 4);
1022 write_lock_bh(&nf_conntrack_lock
);
1023 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
1024 while (!list_empty(&nf_conntrack_hash
[i
])) {
1025 h
= list_entry(nf_conntrack_hash
[i
].next
,
1026 struct nf_conntrack_tuple_hash
, list
);
1028 bucket
= __hash_conntrack(&h
->tuple
, hashsize
, rnd
);
1029 list_add_tail(&h
->list
, &hash
[bucket
]);
1032 old_size
= nf_conntrack_htable_size
;
1033 old_vmalloced
= nf_conntrack_vmalloc
;
1034 old_hash
= nf_conntrack_hash
;
1036 nf_conntrack_htable_size
= hashsize
;
1037 nf_conntrack_vmalloc
= vmalloced
;
1038 nf_conntrack_hash
= hash
;
1039 nf_conntrack_hash_rnd
= rnd
;
1040 write_unlock_bh(&nf_conntrack_lock
);
1042 free_conntrack_hash(old_hash
, old_vmalloced
, old_size
);
1046 module_param_call(hashsize
, set_hashsize
, param_get_uint
,
1047 &nf_conntrack_htable_size
, 0600);
1049 int __init
nf_conntrack_init(void)
1053 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1054 * machine has 256 buckets. >= 1GB machines have 8192 buckets. */
1055 if (!nf_conntrack_htable_size
) {
1056 nf_conntrack_htable_size
1057 = (((num_physpages
<< PAGE_SHIFT
) / 16384)
1058 / sizeof(struct list_head
));
1059 if (num_physpages
> (1024 * 1024 * 1024 / PAGE_SIZE
))
1060 nf_conntrack_htable_size
= 8192;
1061 if (nf_conntrack_htable_size
< 16)
1062 nf_conntrack_htable_size
= 16;
1064 nf_conntrack_max
= 8 * nf_conntrack_htable_size
;
1066 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1067 NF_CONNTRACK_VERSION
, nf_conntrack_htable_size
,
1070 nf_conntrack_hash
= 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_cachep
= kmem_cache_create("nf_conntrack",
1078 sizeof(struct nf_conn
),
1080 if (!nf_conntrack_cachep
) {
1081 printk(KERN_ERR
"Unable to create nf_conn slab cache\n");
1085 nf_conntrack_expect_cachep
= kmem_cache_create("nf_conntrack_expect",
1086 sizeof(struct nf_conntrack_expect
),
1088 if (!nf_conntrack_expect_cachep
) {
1089 printk(KERN_ERR
"Unable to create nf_expect slab cache\n");
1090 goto err_free_conntrack_slab
;
1093 ret
= nf_conntrack_proto_init();
1095 goto out_free_expect_slab
;
1097 ret
= nf_conntrack_helper_init();
1099 goto out_fini_proto
;
1101 /* For use by REJECT target */
1102 rcu_assign_pointer(ip_ct_attach
, __nf_conntrack_attach
);
1103 rcu_assign_pointer(nf_ct_destroy
, destroy_conntrack
);
1105 /* Set up fake conntrack:
1106 - to never be deleted, not in any hashes */
1107 atomic_set(&nf_conntrack_untracked
.ct_general
.use
, 1);
1108 /* - and look it like as a confirmed connection */
1109 set_bit(IPS_CONFIRMED_BIT
, &nf_conntrack_untracked
.status
);
1114 nf_conntrack_proto_fini();
1115 out_free_expect_slab
:
1116 kmem_cache_destroy(nf_conntrack_expect_cachep
);
1117 err_free_conntrack_slab
:
1118 kmem_cache_destroy(nf_conntrack_cachep
);
1120 free_conntrack_hash(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1121 nf_conntrack_htable_size
);