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
,
248 const struct nf_conn
*ignored_conntrack
)
250 struct nf_conntrack_tuple_hash
*h
;
252 read_lock_bh(&nf_conntrack_lock
);
253 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
255 atomic_inc(&nf_ct_tuplehash_to_ctrack(h
)->ct_general
.use
);
256 read_unlock_bh(&nf_conntrack_lock
);
260 EXPORT_SYMBOL_GPL(nf_conntrack_find_get
);
262 static void __nf_conntrack_hash_insert(struct nf_conn
*ct
,
264 unsigned int repl_hash
)
266 ct
->id
= ++nf_conntrack_next_id
;
267 hlist_add_head(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
,
268 &nf_conntrack_hash
[hash
]);
269 hlist_add_head(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnode
,
270 &nf_conntrack_hash
[repl_hash
]);
273 void nf_conntrack_hash_insert(struct nf_conn
*ct
)
275 unsigned int hash
, repl_hash
;
277 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
278 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
280 write_lock_bh(&nf_conntrack_lock
);
281 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
282 write_unlock_bh(&nf_conntrack_lock
);
284 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert
);
286 /* Confirm a connection given skb; places it in hash table */
288 __nf_conntrack_confirm(struct sk_buff
**pskb
)
290 unsigned int hash
, repl_hash
;
291 struct nf_conntrack_tuple_hash
*h
;
293 struct nf_conn_help
*help
;
294 struct hlist_node
*n
;
295 enum ip_conntrack_info ctinfo
;
297 ct
= nf_ct_get(*pskb
, &ctinfo
);
299 /* ipt_REJECT uses nf_conntrack_attach to attach related
300 ICMP/TCP RST packets in other direction. Actual packet
301 which created connection will be IP_CT_NEW or for an
302 expected connection, IP_CT_RELATED. */
303 if (CTINFO2DIR(ctinfo
) != IP_CT_DIR_ORIGINAL
)
306 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
307 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
309 /* We're not in hash table, and we refuse to set up related
310 connections for unconfirmed conns. But packet copies and
311 REJECT will give spurious warnings here. */
312 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
314 /* No external references means noone else could have
316 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
317 DEBUGP("Confirming conntrack %p\n", ct
);
319 write_lock_bh(&nf_conntrack_lock
);
321 /* See if there's one in the list already, including reverse:
322 NAT could have grabbed it without realizing, since we're
323 not in the hash. If there is, we lost race. */
324 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[hash
], hnode
)
325 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
328 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[repl_hash
], hnode
)
329 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
333 /* Remove from unconfirmed list */
334 hlist_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
);
336 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
337 /* Timer relative to confirmation time, not original
338 setting time, otherwise we'd get timer wrap in
339 weird delay cases. */
340 ct
->timeout
.expires
+= jiffies
;
341 add_timer(&ct
->timeout
);
342 atomic_inc(&ct
->ct_general
.use
);
343 set_bit(IPS_CONFIRMED_BIT
, &ct
->status
);
344 NF_CT_STAT_INC(insert
);
345 write_unlock_bh(&nf_conntrack_lock
);
346 help
= nfct_help(ct
);
347 if (help
&& help
->helper
)
348 nf_conntrack_event_cache(IPCT_HELPER
, *pskb
);
349 #ifdef CONFIG_NF_NAT_NEEDED
350 if (test_bit(IPS_SRC_NAT_DONE_BIT
, &ct
->status
) ||
351 test_bit(IPS_DST_NAT_DONE_BIT
, &ct
->status
))
352 nf_conntrack_event_cache(IPCT_NATINFO
, *pskb
);
354 nf_conntrack_event_cache(master_ct(ct
) ?
355 IPCT_RELATED
: IPCT_NEW
, *pskb
);
359 NF_CT_STAT_INC(insert_failed
);
360 write_unlock_bh(&nf_conntrack_lock
);
363 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm
);
365 /* Returns true if a connection correspondings to the tuple (required
368 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple
*tuple
,
369 const struct nf_conn
*ignored_conntrack
)
371 struct nf_conntrack_tuple_hash
*h
;
373 read_lock_bh(&nf_conntrack_lock
);
374 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
375 read_unlock_bh(&nf_conntrack_lock
);
379 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken
);
381 /* There's a small race here where we may free a just-assured
382 connection. Too bad: we're in trouble anyway. */
383 static int early_drop(struct hlist_head
*chain
)
385 /* Use oldest entry, which is roughly LRU */
386 struct nf_conntrack_tuple_hash
*h
;
387 struct nf_conn
*ct
= NULL
, *tmp
;
388 struct hlist_node
*n
;
391 read_lock_bh(&nf_conntrack_lock
);
392 hlist_for_each_entry(h
, n
, chain
, hnode
) {
393 tmp
= nf_ct_tuplehash_to_ctrack(h
);
394 if (!test_bit(IPS_ASSURED_BIT
, &tmp
->status
))
398 atomic_inc(&ct
->ct_general
.use
);
399 read_unlock_bh(&nf_conntrack_lock
);
404 if (del_timer(&ct
->timeout
)) {
405 death_by_timeout((unsigned long)ct
);
407 NF_CT_STAT_INC_ATOMIC(early_drop
);
413 struct nf_conn
*nf_conntrack_alloc(const struct nf_conntrack_tuple
*orig
,
414 const struct nf_conntrack_tuple
*repl
)
416 struct nf_conn
*conntrack
= NULL
;
418 if (unlikely(!nf_conntrack_hash_rnd_initted
)) {
419 get_random_bytes(&nf_conntrack_hash_rnd
, 4);
420 nf_conntrack_hash_rnd_initted
= 1;
423 /* We don't want any race condition at early drop stage */
424 atomic_inc(&nf_conntrack_count
);
427 && atomic_read(&nf_conntrack_count
) > nf_conntrack_max
) {
428 unsigned int hash
= hash_conntrack(orig
);
429 /* Try dropping from this hash chain. */
430 if (!early_drop(&nf_conntrack_hash
[hash
])) {
431 atomic_dec(&nf_conntrack_count
);
434 "nf_conntrack: table full, dropping"
436 return ERR_PTR(-ENOMEM
);
440 conntrack
= kmem_cache_zalloc(nf_conntrack_cachep
, GFP_ATOMIC
);
441 if (conntrack
== NULL
) {
442 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack.\n");
443 atomic_dec(&nf_conntrack_count
);
444 return ERR_PTR(-ENOMEM
);
447 atomic_set(&conntrack
->ct_general
.use
, 1);
448 conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
= *orig
;
449 conntrack
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *repl
;
450 /* Don't set timer yet: wait for confirmation */
451 setup_timer(&conntrack
->timeout
, death_by_timeout
,
452 (unsigned long)conntrack
);
456 EXPORT_SYMBOL_GPL(nf_conntrack_alloc
);
458 void nf_conntrack_free(struct nf_conn
*conntrack
)
460 nf_ct_ext_free(conntrack
);
461 kmem_cache_free(nf_conntrack_cachep
, conntrack
);
462 atomic_dec(&nf_conntrack_count
);
464 EXPORT_SYMBOL_GPL(nf_conntrack_free
);
466 /* Allocate a new conntrack: we return -ENOMEM if classification
467 failed due to stress. Otherwise it really is unclassifiable. */
468 static struct nf_conntrack_tuple_hash
*
469 init_conntrack(const struct nf_conntrack_tuple
*tuple
,
470 struct nf_conntrack_l3proto
*l3proto
,
471 struct nf_conntrack_l4proto
*l4proto
,
473 unsigned int dataoff
)
475 struct nf_conn
*conntrack
;
476 struct nf_conn_help
*help
;
477 struct nf_conntrack_tuple repl_tuple
;
478 struct nf_conntrack_expect
*exp
;
480 if (!nf_ct_invert_tuple(&repl_tuple
, tuple
, l3proto
, l4proto
)) {
481 DEBUGP("Can't invert tuple.\n");
485 conntrack
= nf_conntrack_alloc(tuple
, &repl_tuple
);
486 if (conntrack
== NULL
|| IS_ERR(conntrack
)) {
487 DEBUGP("Can't allocate conntrack.\n");
488 return (struct nf_conntrack_tuple_hash
*)conntrack
;
491 if (!l4proto
->new(conntrack
, skb
, dataoff
)) {
492 nf_conntrack_free(conntrack
);
493 DEBUGP("init conntrack: can't track with proto module\n");
497 write_lock_bh(&nf_conntrack_lock
);
498 exp
= find_expectation(tuple
);
500 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
502 /* Welcome, Mr. Bond. We've been expecting you... */
503 __set_bit(IPS_EXPECTED_BIT
, &conntrack
->status
);
504 conntrack
->master
= exp
->master
;
506 help
= nf_ct_ext_add(conntrack
, NF_CT_EXT_HELPER
,
509 rcu_assign_pointer(help
->helper
, exp
->helper
);
511 DEBUGP("failed to add helper extension area");
514 #ifdef CONFIG_NF_CONNTRACK_MARK
515 conntrack
->mark
= exp
->master
->mark
;
517 #ifdef CONFIG_NF_CONNTRACK_SECMARK
518 conntrack
->secmark
= exp
->master
->secmark
;
520 nf_conntrack_get(&conntrack
->master
->ct_general
);
521 NF_CT_STAT_INC(expect_new
);
523 struct nf_conntrack_helper
*helper
;
525 helper
= __nf_ct_helper_find(&repl_tuple
);
527 help
= nf_ct_ext_add(conntrack
, NF_CT_EXT_HELPER
,
530 /* not in hash table yet, so not strictly
532 rcu_assign_pointer(help
->helper
, helper
);
534 DEBUGP("failed to add helper extension area");
539 /* Overload tuple linked list to put us in unconfirmed list. */
540 hlist_add_head(&conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
,
543 write_unlock_bh(&nf_conntrack_lock
);
547 exp
->expectfn(conntrack
, exp
);
548 nf_conntrack_expect_put(exp
);
551 return &conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
];
554 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
555 static inline struct nf_conn
*
556 resolve_normal_ct(struct sk_buff
*skb
,
557 unsigned int dataoff
,
560 struct nf_conntrack_l3proto
*l3proto
,
561 struct nf_conntrack_l4proto
*l4proto
,
563 enum ip_conntrack_info
*ctinfo
)
565 struct nf_conntrack_tuple tuple
;
566 struct nf_conntrack_tuple_hash
*h
;
569 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
),
570 dataoff
, l3num
, protonum
, &tuple
, l3proto
,
572 DEBUGP("resolve_normal_ct: Can't get tuple\n");
576 /* look for tuple match */
577 h
= nf_conntrack_find_get(&tuple
, NULL
);
579 h
= init_conntrack(&tuple
, l3proto
, l4proto
, skb
, dataoff
);
585 ct
= nf_ct_tuplehash_to_ctrack(h
);
587 /* It exists; we have (non-exclusive) reference. */
588 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
) {
589 *ctinfo
= IP_CT_ESTABLISHED
+ IP_CT_IS_REPLY
;
590 /* Please set reply bit if this packet OK */
593 /* Once we've had two way comms, always ESTABLISHED. */
594 if (test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
595 DEBUGP("nf_conntrack_in: normal packet for %p\n", ct
);
596 *ctinfo
= IP_CT_ESTABLISHED
;
597 } else if (test_bit(IPS_EXPECTED_BIT
, &ct
->status
)) {
598 DEBUGP("nf_conntrack_in: related packet for %p\n", ct
);
599 *ctinfo
= IP_CT_RELATED
;
601 DEBUGP("nf_conntrack_in: new packet for %p\n", ct
);
606 skb
->nfct
= &ct
->ct_general
;
607 skb
->nfctinfo
= *ctinfo
;
612 nf_conntrack_in(int pf
, unsigned int hooknum
, struct sk_buff
**pskb
)
615 enum ip_conntrack_info ctinfo
;
616 struct nf_conntrack_l3proto
*l3proto
;
617 struct nf_conntrack_l4proto
*l4proto
;
618 unsigned int dataoff
;
623 /* Previously seen (loopback or untracked)? Ignore. */
625 NF_CT_STAT_INC_ATOMIC(ignore
);
629 /* rcu_read_lock()ed by nf_hook_slow */
630 l3proto
= __nf_ct_l3proto_find((u_int16_t
)pf
);
632 if ((ret
= l3proto
->prepare(pskb
, hooknum
, &dataoff
, &protonum
)) <= 0) {
633 DEBUGP("not prepared to track yet or error occured\n");
637 l4proto
= __nf_ct_l4proto_find((u_int16_t
)pf
, protonum
);
639 /* It may be an special packet, error, unclean...
640 * inverse of the return code tells to the netfilter
641 * core what to do with the packet. */
642 if (l4proto
->error
!= NULL
&&
643 (ret
= l4proto
->error(*pskb
, dataoff
, &ctinfo
, pf
, hooknum
)) <= 0) {
644 NF_CT_STAT_INC_ATOMIC(error
);
645 NF_CT_STAT_INC_ATOMIC(invalid
);
649 ct
= resolve_normal_ct(*pskb
, dataoff
, pf
, protonum
, l3proto
, l4proto
,
650 &set_reply
, &ctinfo
);
652 /* Not valid part of a connection */
653 NF_CT_STAT_INC_ATOMIC(invalid
);
658 /* Too stressed to deal. */
659 NF_CT_STAT_INC_ATOMIC(drop
);
663 NF_CT_ASSERT((*pskb
)->nfct
);
665 ret
= l4proto
->packet(ct
, *pskb
, dataoff
, ctinfo
, pf
, hooknum
);
667 /* Invalid: inverse of the return code tells
668 * the netfilter core what to do */
669 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
670 nf_conntrack_put((*pskb
)->nfct
);
671 (*pskb
)->nfct
= NULL
;
672 NF_CT_STAT_INC_ATOMIC(invalid
);
676 if (set_reply
&& !test_and_set_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
))
677 nf_conntrack_event_cache(IPCT_STATUS
, *pskb
);
681 EXPORT_SYMBOL_GPL(nf_conntrack_in
);
683 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple
*inverse
,
684 const struct nf_conntrack_tuple
*orig
)
689 ret
= nf_ct_invert_tuple(inverse
, orig
,
690 __nf_ct_l3proto_find(orig
->src
.l3num
),
691 __nf_ct_l4proto_find(orig
->src
.l3num
,
692 orig
->dst
.protonum
));
696 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr
);
698 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
699 implicitly racy: see __nf_conntrack_confirm */
700 void nf_conntrack_alter_reply(struct nf_conn
*ct
,
701 const struct nf_conntrack_tuple
*newreply
)
703 struct nf_conn_help
*help
= nfct_help(ct
);
704 struct nf_conntrack_helper
*helper
;
706 write_lock_bh(&nf_conntrack_lock
);
707 /* Should be unconfirmed, so not in hash table yet */
708 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
710 DEBUGP("Altering reply tuple of %p to ", ct
);
711 NF_CT_DUMP_TUPLE(newreply
);
713 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *newreply
;
714 if (ct
->master
|| (help
&& help
->expecting
!= 0))
717 helper
= __nf_ct_helper_find(newreply
);
718 if (helper
== NULL
) {
720 rcu_assign_pointer(help
->helper
, NULL
);
725 help
= nf_ct_ext_add(ct
, NF_CT_EXT_HELPER
, GFP_ATOMIC
);
727 DEBUGP("failed to add helper extension area");
731 memset(&help
->help
, 0, sizeof(help
->help
));
734 rcu_assign_pointer(help
->helper
, helper
);
736 write_unlock_bh(&nf_conntrack_lock
);
738 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply
);
740 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
741 void __nf_ct_refresh_acct(struct nf_conn
*ct
,
742 enum ip_conntrack_info ctinfo
,
743 const struct sk_buff
*skb
,
744 unsigned long extra_jiffies
,
749 NF_CT_ASSERT(ct
->timeout
.data
== (unsigned long)ct
);
752 write_lock_bh(&nf_conntrack_lock
);
754 /* Only update if this is not a fixed timeout */
755 if (test_bit(IPS_FIXED_TIMEOUT_BIT
, &ct
->status
)) {
756 write_unlock_bh(&nf_conntrack_lock
);
760 /* If not in hash table, timer will not be active yet */
761 if (!nf_ct_is_confirmed(ct
)) {
762 ct
->timeout
.expires
= extra_jiffies
;
763 event
= IPCT_REFRESH
;
765 unsigned long newtime
= jiffies
+ extra_jiffies
;
767 /* Only update the timeout if the new timeout is at least
768 HZ jiffies from the old timeout. Need del_timer for race
769 avoidance (may already be dying). */
770 if (newtime
- ct
->timeout
.expires
>= HZ
771 && del_timer(&ct
->timeout
)) {
772 ct
->timeout
.expires
= newtime
;
773 add_timer(&ct
->timeout
);
774 event
= IPCT_REFRESH
;
778 #ifdef CONFIG_NF_CT_ACCT
780 ct
->counters
[CTINFO2DIR(ctinfo
)].packets
++;
781 ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
+=
782 skb
->len
- skb_network_offset(skb
);
784 if ((ct
->counters
[CTINFO2DIR(ctinfo
)].packets
& 0x80000000)
785 || (ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
& 0x80000000))
786 event
|= IPCT_COUNTER_FILLING
;
790 write_unlock_bh(&nf_conntrack_lock
);
792 /* must be unlocked when calling event cache */
794 nf_conntrack_event_cache(event
, skb
);
796 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct
);
798 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
800 #include <linux/netfilter/nfnetlink.h>
801 #include <linux/netfilter/nfnetlink_conntrack.h>
802 #include <linux/mutex.h>
805 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
806 * in ip_conntrack_core, since we don't want the protocols to autoload
807 * or depend on ctnetlink */
808 int nf_ct_port_tuple_to_nfattr(struct sk_buff
*skb
,
809 const struct nf_conntrack_tuple
*tuple
)
811 NFA_PUT(skb
, CTA_PROTO_SRC_PORT
, sizeof(u_int16_t
),
812 &tuple
->src
.u
.tcp
.port
);
813 NFA_PUT(skb
, CTA_PROTO_DST_PORT
, sizeof(u_int16_t
),
814 &tuple
->dst
.u
.tcp
.port
);
820 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr
);
822 static const size_t cta_min_proto
[CTA_PROTO_MAX
] = {
823 [CTA_PROTO_SRC_PORT
-1] = sizeof(u_int16_t
),
824 [CTA_PROTO_DST_PORT
-1] = sizeof(u_int16_t
)
827 int nf_ct_port_nfattr_to_tuple(struct nfattr
*tb
[],
828 struct nf_conntrack_tuple
*t
)
830 if (!tb
[CTA_PROTO_SRC_PORT
-1] || !tb
[CTA_PROTO_DST_PORT
-1])
833 if (nfattr_bad_size(tb
, CTA_PROTO_MAX
, cta_min_proto
))
836 t
->src
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_SRC_PORT
-1]);
837 t
->dst
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_DST_PORT
-1]);
841 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple
);
844 /* Used by ipt_REJECT and ip6t_REJECT. */
845 void __nf_conntrack_attach(struct sk_buff
*nskb
, struct sk_buff
*skb
)
848 enum ip_conntrack_info ctinfo
;
850 /* This ICMP is in reverse direction to the packet which caused it */
851 ct
= nf_ct_get(skb
, &ctinfo
);
852 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
)
853 ctinfo
= IP_CT_RELATED
+ IP_CT_IS_REPLY
;
855 ctinfo
= IP_CT_RELATED
;
857 /* Attach to new skbuff, and increment count */
858 nskb
->nfct
= &ct
->ct_general
;
859 nskb
->nfctinfo
= ctinfo
;
860 nf_conntrack_get(nskb
->nfct
);
862 EXPORT_SYMBOL_GPL(__nf_conntrack_attach
);
865 do_iter(const struct nf_conntrack_tuple_hash
*i
,
866 int (*iter
)(struct nf_conn
*i
, void *data
),
869 return iter(nf_ct_tuplehash_to_ctrack(i
), data
);
872 /* Bring out ya dead! */
873 static struct nf_conn
*
874 get_next_corpse(int (*iter
)(struct nf_conn
*i
, void *data
),
875 void *data
, unsigned int *bucket
)
877 struct nf_conntrack_tuple_hash
*h
;
879 struct hlist_node
*n
;
881 write_lock_bh(&nf_conntrack_lock
);
882 for (; *bucket
< nf_conntrack_htable_size
; (*bucket
)++) {
883 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[*bucket
], hnode
) {
884 ct
= nf_ct_tuplehash_to_ctrack(h
);
889 hlist_for_each_entry(h
, n
, &unconfirmed
, hnode
) {
890 ct
= nf_ct_tuplehash_to_ctrack(h
);
892 set_bit(IPS_DYING_BIT
, &ct
->status
);
894 write_unlock_bh(&nf_conntrack_lock
);
897 atomic_inc(&ct
->ct_general
.use
);
898 write_unlock_bh(&nf_conntrack_lock
);
903 nf_ct_iterate_cleanup(int (*iter
)(struct nf_conn
*i
, void *data
), void *data
)
906 unsigned int bucket
= 0;
908 while ((ct
= get_next_corpse(iter
, data
, &bucket
)) != NULL
) {
909 /* Time to push up daises... */
910 if (del_timer(&ct
->timeout
))
911 death_by_timeout((unsigned long)ct
);
912 /* ... else the timer will get him soon. */
917 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup
);
919 static int kill_all(struct nf_conn
*i
, void *data
)
924 static void free_conntrack_hash(struct hlist_head
*hash
, int vmalloced
,
930 free_pages((unsigned long)hash
,
931 get_order(sizeof(struct hlist_head
) * size
));
934 void nf_conntrack_flush(void)
936 nf_ct_iterate_cleanup(kill_all
, NULL
);
938 EXPORT_SYMBOL_GPL(nf_conntrack_flush
);
940 /* Mishearing the voices in his head, our hero wonders how he's
941 supposed to kill the mall. */
942 void nf_conntrack_cleanup(void)
944 rcu_assign_pointer(ip_ct_attach
, NULL
);
946 /* This makes sure all current packets have passed through
947 netfilter framework. Roll on, two-stage module
951 nf_ct_event_cache_flush();
953 nf_conntrack_flush();
954 if (atomic_read(&nf_conntrack_count
) != 0) {
956 goto i_see_dead_people
;
958 /* wait until all references to nf_conntrack_untracked are dropped */
959 while (atomic_read(&nf_conntrack_untracked
.ct_general
.use
) > 1)
962 rcu_assign_pointer(nf_ct_destroy
, NULL
);
964 kmem_cache_destroy(nf_conntrack_cachep
);
965 kmem_cache_destroy(nf_conntrack_expect_cachep
);
966 free_conntrack_hash(nf_conntrack_hash
, nf_conntrack_vmalloc
,
967 nf_conntrack_htable_size
);
969 nf_conntrack_proto_fini();
970 nf_conntrack_helper_fini();
973 static struct hlist_head
*alloc_hashtable(int *sizep
, int *vmalloced
)
975 struct hlist_head
*hash
;
976 unsigned int size
, i
;
980 size
= *sizep
= roundup(*sizep
, PAGE_SIZE
/ sizeof(struct hlist_head
));
981 hash
= (void*)__get_free_pages(GFP_KERNEL
,
982 get_order(sizeof(struct hlist_head
)
986 printk(KERN_WARNING
"nf_conntrack: falling back to vmalloc.\n");
987 hash
= vmalloc(sizeof(struct hlist_head
) * size
);
991 for (i
= 0; i
< size
; i
++)
992 INIT_HLIST_HEAD(&hash
[i
]);
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
= 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 free_conntrack_hash(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
= 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 nf_conntrack_expect_cachep
= kmem_cache_create("nf_conntrack_expect",
1092 sizeof(struct nf_conntrack_expect
),
1094 if (!nf_conntrack_expect_cachep
) {
1095 printk(KERN_ERR
"Unable to create nf_expect slab cache\n");
1096 goto err_free_conntrack_slab
;
1099 ret
= nf_conntrack_proto_init();
1101 goto out_free_expect_slab
;
1103 ret
= nf_conntrack_helper_init();
1105 goto out_fini_proto
;
1107 /* For use by REJECT target */
1108 rcu_assign_pointer(ip_ct_attach
, __nf_conntrack_attach
);
1109 rcu_assign_pointer(nf_ct_destroy
, destroy_conntrack
);
1111 /* Set up fake conntrack:
1112 - to never be deleted, not in any hashes */
1113 atomic_set(&nf_conntrack_untracked
.ct_general
.use
, 1);
1114 /* - and look it like as a confirmed connection */
1115 set_bit(IPS_CONFIRMED_BIT
, &nf_conntrack_untracked
.status
);
1120 nf_conntrack_proto_fini();
1121 out_free_expect_slab
:
1122 kmem_cache_destroy(nf_conntrack_expect_cachep
);
1123 err_free_conntrack_slab
:
1124 kmem_cache_destroy(nf_conntrack_cachep
);
1126 free_conntrack_hash(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1127 nf_conntrack_htable_size
);