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"
43 DEFINE_RWLOCK(nf_conntrack_lock
);
44 EXPORT_SYMBOL_GPL(nf_conntrack_lock
);
46 /* nf_conntrack_standalone needs this */
47 atomic_t nf_conntrack_count
= ATOMIC_INIT(0);
48 EXPORT_SYMBOL_GPL(nf_conntrack_count
);
50 unsigned int nf_conntrack_htable_size __read_mostly
;
51 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size
);
53 int nf_conntrack_max __read_mostly
;
54 EXPORT_SYMBOL_GPL(nf_conntrack_max
);
56 struct hlist_head
*nf_conntrack_hash __read_mostly
;
57 EXPORT_SYMBOL_GPL(nf_conntrack_hash
);
59 struct nf_conn nf_conntrack_untracked __read_mostly
;
60 EXPORT_SYMBOL_GPL(nf_conntrack_untracked
);
62 unsigned int nf_ct_log_invalid __read_mostly
;
63 HLIST_HEAD(unconfirmed
);
64 static int nf_conntrack_vmalloc __read_mostly
;
65 static struct kmem_cache
*nf_conntrack_cachep __read_mostly
;
66 static unsigned int nf_conntrack_next_id
;
68 DEFINE_PER_CPU(struct ip_conntrack_stat
, nf_conntrack_stat
);
69 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat
);
71 static int nf_conntrack_hash_rnd_initted
;
72 static unsigned int nf_conntrack_hash_rnd
;
74 static u_int32_t
__hash_conntrack(const struct nf_conntrack_tuple
*tuple
,
75 unsigned int size
, unsigned int rnd
)
79 a
= jhash2(tuple
->src
.u3
.all
, ARRAY_SIZE(tuple
->src
.u3
.all
),
80 (tuple
->src
.l3num
<< 16) | tuple
->dst
.protonum
);
81 b
= jhash2(tuple
->dst
.u3
.all
, ARRAY_SIZE(tuple
->dst
.u3
.all
),
82 ((__force __u16
)tuple
->src
.u
.all
<< 16) |
83 (__force __u16
)tuple
->dst
.u
.all
);
85 return jhash_2words(a
, b
, rnd
) % size
;
88 static inline u_int32_t
hash_conntrack(const struct nf_conntrack_tuple
*tuple
)
90 return __hash_conntrack(tuple
, nf_conntrack_htable_size
,
91 nf_conntrack_hash_rnd
);
95 nf_ct_get_tuple(const struct sk_buff
*skb
,
100 struct nf_conntrack_tuple
*tuple
,
101 const struct nf_conntrack_l3proto
*l3proto
,
102 const struct nf_conntrack_l4proto
*l4proto
)
104 NF_CT_TUPLE_U_BLANK(tuple
);
106 tuple
->src
.l3num
= l3num
;
107 if (l3proto
->pkt_to_tuple(skb
, nhoff
, tuple
) == 0)
110 tuple
->dst
.protonum
= protonum
;
111 tuple
->dst
.dir
= IP_CT_DIR_ORIGINAL
;
113 return l4proto
->pkt_to_tuple(skb
, dataoff
, tuple
);
115 EXPORT_SYMBOL_GPL(nf_ct_get_tuple
);
117 int nf_ct_get_tuplepr(const struct sk_buff
*skb
,
120 struct nf_conntrack_tuple
*tuple
)
122 struct nf_conntrack_l3proto
*l3proto
;
123 struct nf_conntrack_l4proto
*l4proto
;
124 unsigned int protoff
;
130 l3proto
= __nf_ct_l3proto_find(l3num
);
131 ret
= l3proto
->get_l4proto(skb
, nhoff
, &protoff
, &protonum
);
132 if (ret
!= NF_ACCEPT
) {
137 l4proto
= __nf_ct_l4proto_find(l3num
, protonum
);
139 ret
= nf_ct_get_tuple(skb
, nhoff
, protoff
, l3num
, protonum
, tuple
,
145 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr
);
148 nf_ct_invert_tuple(struct nf_conntrack_tuple
*inverse
,
149 const struct nf_conntrack_tuple
*orig
,
150 const struct nf_conntrack_l3proto
*l3proto
,
151 const struct nf_conntrack_l4proto
*l4proto
)
153 NF_CT_TUPLE_U_BLANK(inverse
);
155 inverse
->src
.l3num
= orig
->src
.l3num
;
156 if (l3proto
->invert_tuple(inverse
, orig
) == 0)
159 inverse
->dst
.dir
= !orig
->dst
.dir
;
161 inverse
->dst
.protonum
= orig
->dst
.protonum
;
162 return l4proto
->invert_tuple(inverse
, orig
);
164 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple
);
167 clean_from_lists(struct nf_conn
*ct
)
169 pr_debug("clean_from_lists(%p)\n", ct
);
170 hlist_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
);
171 hlist_del(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnode
);
173 /* Destroy all pending expectations */
174 nf_ct_remove_expectations(ct
);
178 destroy_conntrack(struct nf_conntrack
*nfct
)
180 struct nf_conn
*ct
= (struct nf_conn
*)nfct
;
181 struct nf_conntrack_l4proto
*l4proto
;
183 pr_debug("destroy_conntrack(%p)\n", ct
);
184 NF_CT_ASSERT(atomic_read(&nfct
->use
) == 0);
185 NF_CT_ASSERT(!timer_pending(&ct
->timeout
));
187 nf_conntrack_event(IPCT_DESTROY
, ct
);
188 set_bit(IPS_DYING_BIT
, &ct
->status
);
190 /* To make sure we don't get any weird locking issues here:
191 * destroy_conntrack() MUST NOT be called with a write lock
192 * to nf_conntrack_lock!!! -HW */
194 l4proto
= __nf_ct_l4proto_find(ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.src
.l3num
,
195 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.protonum
);
196 if (l4proto
&& l4proto
->destroy
)
197 l4proto
->destroy(ct
);
199 nf_ct_ext_destroy(ct
);
203 write_lock_bh(&nf_conntrack_lock
);
204 /* Expectations will have been removed in clean_from_lists,
205 * except TFTP can create an expectation on the first packet,
206 * before connection is in the list, so we need to clean here,
208 nf_ct_remove_expectations(ct
);
210 /* We overload first tuple to link into unconfirmed list. */
211 if (!nf_ct_is_confirmed(ct
)) {
212 BUG_ON(hlist_unhashed(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
));
213 hlist_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
);
216 NF_CT_STAT_INC(delete);
217 write_unlock_bh(&nf_conntrack_lock
);
220 nf_ct_put(ct
->master
);
222 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct
);
223 nf_conntrack_free(ct
);
226 static void death_by_timeout(unsigned long ul_conntrack
)
228 struct nf_conn
*ct
= (void *)ul_conntrack
;
229 struct nf_conn_help
*help
= nfct_help(ct
);
230 struct nf_conntrack_helper
*helper
;
234 helper
= rcu_dereference(help
->helper
);
235 if (helper
&& helper
->destroy
)
240 write_lock_bh(&nf_conntrack_lock
);
241 /* Inside lock so preempt is disabled on module removal path.
242 * Otherwise we can get spurious warnings. */
243 NF_CT_STAT_INC(delete_list
);
244 clean_from_lists(ct
);
245 write_unlock_bh(&nf_conntrack_lock
);
249 struct nf_conntrack_tuple_hash
*
250 __nf_conntrack_find(const struct nf_conntrack_tuple
*tuple
,
251 const struct nf_conn
*ignored_conntrack
)
253 struct nf_conntrack_tuple_hash
*h
;
254 struct hlist_node
*n
;
255 unsigned int hash
= hash_conntrack(tuple
);
257 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[hash
], hnode
) {
258 if (nf_ct_tuplehash_to_ctrack(h
) != ignored_conntrack
&&
259 nf_ct_tuple_equal(tuple
, &h
->tuple
)) {
260 NF_CT_STAT_INC(found
);
263 NF_CT_STAT_INC(searched
);
268 EXPORT_SYMBOL_GPL(__nf_conntrack_find
);
270 /* Find a connection corresponding to a tuple. */
271 struct nf_conntrack_tuple_hash
*
272 nf_conntrack_find_get(const struct nf_conntrack_tuple
*tuple
)
274 struct nf_conntrack_tuple_hash
*h
;
276 read_lock_bh(&nf_conntrack_lock
);
277 h
= __nf_conntrack_find(tuple
, NULL
);
279 atomic_inc(&nf_ct_tuplehash_to_ctrack(h
)->ct_general
.use
);
280 read_unlock_bh(&nf_conntrack_lock
);
284 EXPORT_SYMBOL_GPL(nf_conntrack_find_get
);
286 static void __nf_conntrack_hash_insert(struct nf_conn
*ct
,
288 unsigned int repl_hash
)
290 ct
->id
= ++nf_conntrack_next_id
;
291 hlist_add_head(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
,
292 &nf_conntrack_hash
[hash
]);
293 hlist_add_head(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnode
,
294 &nf_conntrack_hash
[repl_hash
]);
297 void nf_conntrack_hash_insert(struct nf_conn
*ct
)
299 unsigned int hash
, repl_hash
;
301 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
302 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
304 write_lock_bh(&nf_conntrack_lock
);
305 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
306 write_unlock_bh(&nf_conntrack_lock
);
308 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert
);
310 /* Confirm a connection given skb; places it in hash table */
312 __nf_conntrack_confirm(struct sk_buff
**pskb
)
314 unsigned int hash
, repl_hash
;
315 struct nf_conntrack_tuple_hash
*h
;
317 struct nf_conn_help
*help
;
318 struct hlist_node
*n
;
319 enum ip_conntrack_info ctinfo
;
321 ct
= nf_ct_get(*pskb
, &ctinfo
);
323 /* ipt_REJECT uses nf_conntrack_attach to attach related
324 ICMP/TCP RST packets in other direction. Actual packet
325 which created connection will be IP_CT_NEW or for an
326 expected connection, IP_CT_RELATED. */
327 if (CTINFO2DIR(ctinfo
) != IP_CT_DIR_ORIGINAL
)
330 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
331 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
333 /* We're not in hash table, and we refuse to set up related
334 connections for unconfirmed conns. But packet copies and
335 REJECT will give spurious warnings here. */
336 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
338 /* No external references means noone else could have
340 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
341 pr_debug("Confirming conntrack %p\n", ct
);
343 write_lock_bh(&nf_conntrack_lock
);
345 /* See if there's one in the list already, including reverse:
346 NAT could have grabbed it without realizing, since we're
347 not in the hash. If there is, we lost race. */
348 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[hash
], hnode
)
349 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
352 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[repl_hash
], hnode
)
353 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
357 /* Remove from unconfirmed list */
358 hlist_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
);
360 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
361 /* Timer relative to confirmation time, not original
362 setting time, otherwise we'd get timer wrap in
363 weird delay cases. */
364 ct
->timeout
.expires
+= jiffies
;
365 add_timer(&ct
->timeout
);
366 atomic_inc(&ct
->ct_general
.use
);
367 set_bit(IPS_CONFIRMED_BIT
, &ct
->status
);
368 NF_CT_STAT_INC(insert
);
369 write_unlock_bh(&nf_conntrack_lock
);
370 help
= nfct_help(ct
);
371 if (help
&& help
->helper
)
372 nf_conntrack_event_cache(IPCT_HELPER
, *pskb
);
373 #ifdef CONFIG_NF_NAT_NEEDED
374 if (test_bit(IPS_SRC_NAT_DONE_BIT
, &ct
->status
) ||
375 test_bit(IPS_DST_NAT_DONE_BIT
, &ct
->status
))
376 nf_conntrack_event_cache(IPCT_NATINFO
, *pskb
);
378 nf_conntrack_event_cache(master_ct(ct
) ?
379 IPCT_RELATED
: IPCT_NEW
, *pskb
);
383 NF_CT_STAT_INC(insert_failed
);
384 write_unlock_bh(&nf_conntrack_lock
);
387 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm
);
389 /* Returns true if a connection correspondings to the tuple (required
392 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple
*tuple
,
393 const struct nf_conn
*ignored_conntrack
)
395 struct nf_conntrack_tuple_hash
*h
;
397 read_lock_bh(&nf_conntrack_lock
);
398 h
= __nf_conntrack_find(tuple
, ignored_conntrack
);
399 read_unlock_bh(&nf_conntrack_lock
);
403 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken
);
405 #define NF_CT_EVICTION_RANGE 8
407 /* There's a small race here where we may free a just-assured
408 connection. Too bad: we're in trouble anyway. */
409 static int early_drop(unsigned int hash
)
411 /* Use oldest entry, which is roughly LRU */
412 struct nf_conntrack_tuple_hash
*h
;
413 struct nf_conn
*ct
= NULL
, *tmp
;
414 struct hlist_node
*n
;
415 unsigned int i
, cnt
= 0;
418 read_lock_bh(&nf_conntrack_lock
);
419 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
420 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[hash
], hnode
) {
421 tmp
= nf_ct_tuplehash_to_ctrack(h
);
422 if (!test_bit(IPS_ASSURED_BIT
, &tmp
->status
))
426 if (ct
|| cnt
>= NF_CT_EVICTION_RANGE
)
428 hash
= (hash
+ 1) % nf_conntrack_htable_size
;
431 atomic_inc(&ct
->ct_general
.use
);
432 read_unlock_bh(&nf_conntrack_lock
);
437 if (del_timer(&ct
->timeout
)) {
438 death_by_timeout((unsigned long)ct
);
440 NF_CT_STAT_INC_ATOMIC(early_drop
);
446 struct nf_conn
*nf_conntrack_alloc(const struct nf_conntrack_tuple
*orig
,
447 const struct nf_conntrack_tuple
*repl
)
449 struct nf_conn
*conntrack
= NULL
;
451 if (unlikely(!nf_conntrack_hash_rnd_initted
)) {
452 get_random_bytes(&nf_conntrack_hash_rnd
, 4);
453 nf_conntrack_hash_rnd_initted
= 1;
456 /* We don't want any race condition at early drop stage */
457 atomic_inc(&nf_conntrack_count
);
460 && atomic_read(&nf_conntrack_count
) > nf_conntrack_max
) {
461 unsigned int hash
= hash_conntrack(orig
);
462 if (!early_drop(hash
)) {
463 atomic_dec(&nf_conntrack_count
);
466 "nf_conntrack: table full, dropping"
468 return ERR_PTR(-ENOMEM
);
472 conntrack
= kmem_cache_zalloc(nf_conntrack_cachep
, GFP_ATOMIC
);
473 if (conntrack
== NULL
) {
474 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
475 atomic_dec(&nf_conntrack_count
);
476 return ERR_PTR(-ENOMEM
);
479 atomic_set(&conntrack
->ct_general
.use
, 1);
480 conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
= *orig
;
481 conntrack
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *repl
;
482 /* Don't set timer yet: wait for confirmation */
483 setup_timer(&conntrack
->timeout
, death_by_timeout
,
484 (unsigned long)conntrack
);
488 EXPORT_SYMBOL_GPL(nf_conntrack_alloc
);
490 void nf_conntrack_free(struct nf_conn
*conntrack
)
492 nf_ct_ext_free(conntrack
);
493 kmem_cache_free(nf_conntrack_cachep
, conntrack
);
494 atomic_dec(&nf_conntrack_count
);
496 EXPORT_SYMBOL_GPL(nf_conntrack_free
);
498 /* Allocate a new conntrack: we return -ENOMEM if classification
499 failed due to stress. Otherwise it really is unclassifiable. */
500 static struct nf_conntrack_tuple_hash
*
501 init_conntrack(const struct nf_conntrack_tuple
*tuple
,
502 struct nf_conntrack_l3proto
*l3proto
,
503 struct nf_conntrack_l4proto
*l4proto
,
505 unsigned int dataoff
)
507 struct nf_conn
*conntrack
;
508 struct nf_conn_help
*help
;
509 struct nf_conntrack_tuple repl_tuple
;
510 struct nf_conntrack_expect
*exp
;
512 if (!nf_ct_invert_tuple(&repl_tuple
, tuple
, l3proto
, l4proto
)) {
513 pr_debug("Can't invert tuple.\n");
517 conntrack
= nf_conntrack_alloc(tuple
, &repl_tuple
);
518 if (conntrack
== NULL
|| IS_ERR(conntrack
)) {
519 pr_debug("Can't allocate conntrack.\n");
520 return (struct nf_conntrack_tuple_hash
*)conntrack
;
523 if (!l4proto
->new(conntrack
, skb
, dataoff
)) {
524 nf_conntrack_free(conntrack
);
525 pr_debug("init conntrack: can't track with proto module\n");
529 write_lock_bh(&nf_conntrack_lock
);
530 exp
= nf_ct_find_expectation(tuple
);
532 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
534 /* Welcome, Mr. Bond. We've been expecting you... */
535 __set_bit(IPS_EXPECTED_BIT
, &conntrack
->status
);
536 conntrack
->master
= exp
->master
;
538 help
= nf_ct_helper_ext_add(conntrack
, GFP_ATOMIC
);
540 rcu_assign_pointer(help
->helper
, exp
->helper
);
543 #ifdef CONFIG_NF_CONNTRACK_MARK
544 conntrack
->mark
= exp
->master
->mark
;
546 #ifdef CONFIG_NF_CONNTRACK_SECMARK
547 conntrack
->secmark
= exp
->master
->secmark
;
549 nf_conntrack_get(&conntrack
->master
->ct_general
);
550 NF_CT_STAT_INC(expect_new
);
552 struct nf_conntrack_helper
*helper
;
554 helper
= __nf_ct_helper_find(&repl_tuple
);
556 help
= nf_ct_helper_ext_add(conntrack
, GFP_ATOMIC
);
558 rcu_assign_pointer(help
->helper
, helper
);
563 /* Overload tuple linked list to put us in unconfirmed list. */
564 hlist_add_head(&conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
,
567 write_unlock_bh(&nf_conntrack_lock
);
571 exp
->expectfn(conntrack
, exp
);
572 nf_ct_expect_put(exp
);
575 return &conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
];
578 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
579 static inline struct nf_conn
*
580 resolve_normal_ct(struct sk_buff
*skb
,
581 unsigned int dataoff
,
584 struct nf_conntrack_l3proto
*l3proto
,
585 struct nf_conntrack_l4proto
*l4proto
,
587 enum ip_conntrack_info
*ctinfo
)
589 struct nf_conntrack_tuple tuple
;
590 struct nf_conntrack_tuple_hash
*h
;
593 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
),
594 dataoff
, l3num
, protonum
, &tuple
, l3proto
,
596 pr_debug("resolve_normal_ct: Can't get tuple\n");
600 /* look for tuple match */
601 h
= nf_conntrack_find_get(&tuple
);
603 h
= init_conntrack(&tuple
, l3proto
, l4proto
, skb
, dataoff
);
609 ct
= nf_ct_tuplehash_to_ctrack(h
);
611 /* It exists; we have (non-exclusive) reference. */
612 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
) {
613 *ctinfo
= IP_CT_ESTABLISHED
+ IP_CT_IS_REPLY
;
614 /* Please set reply bit if this packet OK */
617 /* Once we've had two way comms, always ESTABLISHED. */
618 if (test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
619 pr_debug("nf_conntrack_in: normal packet for %p\n", ct
);
620 *ctinfo
= IP_CT_ESTABLISHED
;
621 } else if (test_bit(IPS_EXPECTED_BIT
, &ct
->status
)) {
622 pr_debug("nf_conntrack_in: related packet for %p\n",
624 *ctinfo
= IP_CT_RELATED
;
626 pr_debug("nf_conntrack_in: new packet for %p\n", ct
);
631 skb
->nfct
= &ct
->ct_general
;
632 skb
->nfctinfo
= *ctinfo
;
637 nf_conntrack_in(int pf
, unsigned int hooknum
, struct sk_buff
**pskb
)
640 enum ip_conntrack_info ctinfo
;
641 struct nf_conntrack_l3proto
*l3proto
;
642 struct nf_conntrack_l4proto
*l4proto
;
643 unsigned int dataoff
;
648 /* Previously seen (loopback or untracked)? Ignore. */
650 NF_CT_STAT_INC_ATOMIC(ignore
);
654 /* rcu_read_lock()ed by nf_hook_slow */
655 l3proto
= __nf_ct_l3proto_find((u_int16_t
)pf
);
656 ret
= l3proto
->get_l4proto(*pskb
, skb_network_offset(*pskb
),
657 &dataoff
, &protonum
);
659 pr_debug("not prepared to track yet or error occured\n");
660 NF_CT_STAT_INC_ATOMIC(error
);
661 NF_CT_STAT_INC_ATOMIC(invalid
);
665 l4proto
= __nf_ct_l4proto_find((u_int16_t
)pf
, protonum
);
667 /* It may be an special packet, error, unclean...
668 * inverse of the return code tells to the netfilter
669 * core what to do with the packet. */
670 if (l4proto
->error
!= NULL
&&
671 (ret
= l4proto
->error(*pskb
, dataoff
, &ctinfo
, pf
, hooknum
)) <= 0) {
672 NF_CT_STAT_INC_ATOMIC(error
);
673 NF_CT_STAT_INC_ATOMIC(invalid
);
677 ct
= resolve_normal_ct(*pskb
, dataoff
, pf
, protonum
, l3proto
, l4proto
,
678 &set_reply
, &ctinfo
);
680 /* Not valid part of a connection */
681 NF_CT_STAT_INC_ATOMIC(invalid
);
686 /* Too stressed to deal. */
687 NF_CT_STAT_INC_ATOMIC(drop
);
691 NF_CT_ASSERT((*pskb
)->nfct
);
693 ret
= l4proto
->packet(ct
, *pskb
, dataoff
, ctinfo
, pf
, hooknum
);
695 /* Invalid: inverse of the return code tells
696 * the netfilter core what to do */
697 pr_debug("nf_conntrack_in: Can't track with proto module\n");
698 nf_conntrack_put((*pskb
)->nfct
);
699 (*pskb
)->nfct
= NULL
;
700 NF_CT_STAT_INC_ATOMIC(invalid
);
704 if (set_reply
&& !test_and_set_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
))
705 nf_conntrack_event_cache(IPCT_STATUS
, *pskb
);
709 EXPORT_SYMBOL_GPL(nf_conntrack_in
);
711 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple
*inverse
,
712 const struct nf_conntrack_tuple
*orig
)
717 ret
= nf_ct_invert_tuple(inverse
, orig
,
718 __nf_ct_l3proto_find(orig
->src
.l3num
),
719 __nf_ct_l4proto_find(orig
->src
.l3num
,
720 orig
->dst
.protonum
));
724 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr
);
726 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
727 implicitly racy: see __nf_conntrack_confirm */
728 void nf_conntrack_alter_reply(struct nf_conn
*ct
,
729 const struct nf_conntrack_tuple
*newreply
)
731 struct nf_conn_help
*help
= nfct_help(ct
);
732 struct nf_conntrack_helper
*helper
;
734 write_lock_bh(&nf_conntrack_lock
);
735 /* Should be unconfirmed, so not in hash table yet */
736 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
738 pr_debug("Altering reply tuple of %p to ", ct
);
739 NF_CT_DUMP_TUPLE(newreply
);
741 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *newreply
;
742 if (ct
->master
|| (help
&& help
->expecting
!= 0))
745 helper
= __nf_ct_helper_find(newreply
);
746 if (helper
== NULL
) {
748 rcu_assign_pointer(help
->helper
, NULL
);
753 help
= nf_ct_helper_ext_add(ct
, GFP_ATOMIC
);
757 memset(&help
->help
, 0, sizeof(help
->help
));
760 rcu_assign_pointer(help
->helper
, helper
);
762 write_unlock_bh(&nf_conntrack_lock
);
764 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply
);
766 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
767 void __nf_ct_refresh_acct(struct nf_conn
*ct
,
768 enum ip_conntrack_info ctinfo
,
769 const struct sk_buff
*skb
,
770 unsigned long extra_jiffies
,
775 NF_CT_ASSERT(ct
->timeout
.data
== (unsigned long)ct
);
778 write_lock_bh(&nf_conntrack_lock
);
780 /* Only update if this is not a fixed timeout */
781 if (test_bit(IPS_FIXED_TIMEOUT_BIT
, &ct
->status
)) {
782 write_unlock_bh(&nf_conntrack_lock
);
786 /* If not in hash table, timer will not be active yet */
787 if (!nf_ct_is_confirmed(ct
)) {
788 ct
->timeout
.expires
= extra_jiffies
;
789 event
= IPCT_REFRESH
;
791 unsigned long newtime
= jiffies
+ extra_jiffies
;
793 /* Only update the timeout if the new timeout is at least
794 HZ jiffies from the old timeout. Need del_timer for race
795 avoidance (may already be dying). */
796 if (newtime
- ct
->timeout
.expires
>= HZ
797 && del_timer(&ct
->timeout
)) {
798 ct
->timeout
.expires
= newtime
;
799 add_timer(&ct
->timeout
);
800 event
= IPCT_REFRESH
;
804 #ifdef CONFIG_NF_CT_ACCT
806 ct
->counters
[CTINFO2DIR(ctinfo
)].packets
++;
807 ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
+=
808 skb
->len
- skb_network_offset(skb
);
810 if ((ct
->counters
[CTINFO2DIR(ctinfo
)].packets
& 0x80000000)
811 || (ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
& 0x80000000))
812 event
|= IPCT_COUNTER_FILLING
;
816 write_unlock_bh(&nf_conntrack_lock
);
818 /* must be unlocked when calling event cache */
820 nf_conntrack_event_cache(event
, skb
);
822 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct
);
824 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
826 #include <linux/netfilter/nfnetlink.h>
827 #include <linux/netfilter/nfnetlink_conntrack.h>
828 #include <linux/mutex.h>
831 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
832 * in ip_conntrack_core, since we don't want the protocols to autoload
833 * or depend on ctnetlink */
834 int nf_ct_port_tuple_to_nfattr(struct sk_buff
*skb
,
835 const struct nf_conntrack_tuple
*tuple
)
837 NFA_PUT(skb
, CTA_PROTO_SRC_PORT
, sizeof(u_int16_t
),
838 &tuple
->src
.u
.tcp
.port
);
839 NFA_PUT(skb
, CTA_PROTO_DST_PORT
, sizeof(u_int16_t
),
840 &tuple
->dst
.u
.tcp
.port
);
846 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr
);
848 static const size_t cta_min_proto
[CTA_PROTO_MAX
] = {
849 [CTA_PROTO_SRC_PORT
-1] = sizeof(u_int16_t
),
850 [CTA_PROTO_DST_PORT
-1] = sizeof(u_int16_t
)
853 int nf_ct_port_nfattr_to_tuple(struct nfattr
*tb
[],
854 struct nf_conntrack_tuple
*t
)
856 if (!tb
[CTA_PROTO_SRC_PORT
-1] || !tb
[CTA_PROTO_DST_PORT
-1])
859 if (nfattr_bad_size(tb
, CTA_PROTO_MAX
, cta_min_proto
))
862 t
->src
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_SRC_PORT
-1]);
863 t
->dst
.u
.tcp
.port
= *(__be16
*)NFA_DATA(tb
[CTA_PROTO_DST_PORT
-1]);
867 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple
);
870 /* Used by ipt_REJECT and ip6t_REJECT. */
871 void __nf_conntrack_attach(struct sk_buff
*nskb
, struct sk_buff
*skb
)
874 enum ip_conntrack_info ctinfo
;
876 /* This ICMP is in reverse direction to the packet which caused it */
877 ct
= nf_ct_get(skb
, &ctinfo
);
878 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
)
879 ctinfo
= IP_CT_RELATED
+ IP_CT_IS_REPLY
;
881 ctinfo
= IP_CT_RELATED
;
883 /* Attach to new skbuff, and increment count */
884 nskb
->nfct
= &ct
->ct_general
;
885 nskb
->nfctinfo
= ctinfo
;
886 nf_conntrack_get(nskb
->nfct
);
888 EXPORT_SYMBOL_GPL(__nf_conntrack_attach
);
891 do_iter(const struct nf_conntrack_tuple_hash
*i
,
892 int (*iter
)(struct nf_conn
*i
, void *data
),
895 return iter(nf_ct_tuplehash_to_ctrack(i
), data
);
898 /* Bring out ya dead! */
899 static struct nf_conn
*
900 get_next_corpse(int (*iter
)(struct nf_conn
*i
, void *data
),
901 void *data
, unsigned int *bucket
)
903 struct nf_conntrack_tuple_hash
*h
;
905 struct hlist_node
*n
;
907 write_lock_bh(&nf_conntrack_lock
);
908 for (; *bucket
< nf_conntrack_htable_size
; (*bucket
)++) {
909 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[*bucket
], hnode
) {
910 ct
= nf_ct_tuplehash_to_ctrack(h
);
915 hlist_for_each_entry(h
, n
, &unconfirmed
, hnode
) {
916 ct
= nf_ct_tuplehash_to_ctrack(h
);
918 set_bit(IPS_DYING_BIT
, &ct
->status
);
920 write_unlock_bh(&nf_conntrack_lock
);
923 atomic_inc(&ct
->ct_general
.use
);
924 write_unlock_bh(&nf_conntrack_lock
);
929 nf_ct_iterate_cleanup(int (*iter
)(struct nf_conn
*i
, void *data
), void *data
)
932 unsigned int bucket
= 0;
934 while ((ct
= get_next_corpse(iter
, data
, &bucket
)) != NULL
) {
935 /* Time to push up daises... */
936 if (del_timer(&ct
->timeout
))
937 death_by_timeout((unsigned long)ct
);
938 /* ... else the timer will get him soon. */
943 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup
);
945 static int kill_all(struct nf_conn
*i
, void *data
)
950 void nf_ct_free_hashtable(struct hlist_head
*hash
, int vmalloced
, int size
)
955 free_pages((unsigned long)hash
,
956 get_order(sizeof(struct hlist_head
) * size
));
958 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable
);
960 void nf_conntrack_flush(void)
962 nf_ct_iterate_cleanup(kill_all
, NULL
);
964 EXPORT_SYMBOL_GPL(nf_conntrack_flush
);
966 /* Mishearing the voices in his head, our hero wonders how he's
967 supposed to kill the mall. */
968 void nf_conntrack_cleanup(void)
970 rcu_assign_pointer(ip_ct_attach
, NULL
);
972 /* This makes sure all current packets have passed through
973 netfilter framework. Roll on, two-stage module
977 nf_ct_event_cache_flush();
979 nf_conntrack_flush();
980 if (atomic_read(&nf_conntrack_count
) != 0) {
982 goto i_see_dead_people
;
984 /* wait until all references to nf_conntrack_untracked are dropped */
985 while (atomic_read(&nf_conntrack_untracked
.ct_general
.use
) > 1)
988 rcu_assign_pointer(nf_ct_destroy
, NULL
);
990 kmem_cache_destroy(nf_conntrack_cachep
);
991 nf_ct_free_hashtable(nf_conntrack_hash
, nf_conntrack_vmalloc
,
992 nf_conntrack_htable_size
);
994 nf_conntrack_proto_fini();
995 nf_conntrack_helper_fini();
996 nf_conntrack_expect_fini();
999 struct hlist_head
*nf_ct_alloc_hashtable(int *sizep
, int *vmalloced
)
1001 struct hlist_head
*hash
;
1002 unsigned int size
, i
;
1006 size
= *sizep
= roundup(*sizep
, PAGE_SIZE
/ sizeof(struct hlist_head
));
1007 hash
= (void*)__get_free_pages(GFP_KERNEL
,
1008 get_order(sizeof(struct hlist_head
)
1012 printk(KERN_WARNING
"nf_conntrack: falling back to vmalloc.\n");
1013 hash
= vmalloc(sizeof(struct hlist_head
) * size
);
1017 for (i
= 0; i
< size
; i
++)
1018 INIT_HLIST_HEAD(&hash
[i
]);
1022 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable
);
1024 int set_hashsize(const char *val
, struct kernel_param
*kp
)
1026 int i
, bucket
, hashsize
, vmalloced
;
1027 int old_vmalloced
, old_size
;
1029 struct hlist_head
*hash
, *old_hash
;
1030 struct nf_conntrack_tuple_hash
*h
;
1032 /* On boot, we can set this without any fancy locking. */
1033 if (!nf_conntrack_htable_size
)
1034 return param_set_uint(val
, kp
);
1036 hashsize
= simple_strtol(val
, NULL
, 0);
1040 hash
= nf_ct_alloc_hashtable(&hashsize
, &vmalloced
);
1044 /* We have to rehahs for the new table anyway, so we also can
1045 * use a newrandom seed */
1046 get_random_bytes(&rnd
, 4);
1048 write_lock_bh(&nf_conntrack_lock
);
1049 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
1050 while (!hlist_empty(&nf_conntrack_hash
[i
])) {
1051 h
= hlist_entry(nf_conntrack_hash
[i
].first
,
1052 struct nf_conntrack_tuple_hash
, hnode
);
1053 hlist_del(&h
->hnode
);
1054 bucket
= __hash_conntrack(&h
->tuple
, hashsize
, rnd
);
1055 hlist_add_head(&h
->hnode
, &hash
[bucket
]);
1058 old_size
= nf_conntrack_htable_size
;
1059 old_vmalloced
= nf_conntrack_vmalloc
;
1060 old_hash
= nf_conntrack_hash
;
1062 nf_conntrack_htable_size
= hashsize
;
1063 nf_conntrack_vmalloc
= vmalloced
;
1064 nf_conntrack_hash
= hash
;
1065 nf_conntrack_hash_rnd
= rnd
;
1066 write_unlock_bh(&nf_conntrack_lock
);
1068 nf_ct_free_hashtable(old_hash
, old_vmalloced
, old_size
);
1072 module_param_call(hashsize
, set_hashsize
, param_get_uint
,
1073 &nf_conntrack_htable_size
, 0600);
1075 int __init
nf_conntrack_init(void)
1080 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1081 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1082 if (!nf_conntrack_htable_size
) {
1083 nf_conntrack_htable_size
1084 = (((num_physpages
<< PAGE_SHIFT
) / 16384)
1085 / sizeof(struct hlist_head
));
1086 if (num_physpages
> (1024 * 1024 * 1024 / PAGE_SIZE
))
1087 nf_conntrack_htable_size
= 16384;
1088 if (nf_conntrack_htable_size
< 32)
1089 nf_conntrack_htable_size
= 32;
1091 /* Use a max. factor of four by default to get the same max as
1092 * with the old struct list_heads. When a table size is given
1093 * we use the old value of 8 to avoid reducing the max.
1097 nf_conntrack_hash
= nf_ct_alloc_hashtable(&nf_conntrack_htable_size
,
1098 &nf_conntrack_vmalloc
);
1099 if (!nf_conntrack_hash
) {
1100 printk(KERN_ERR
"Unable to create nf_conntrack_hash\n");
1104 nf_conntrack_max
= max_factor
* nf_conntrack_htable_size
;
1106 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1107 NF_CONNTRACK_VERSION
, nf_conntrack_htable_size
,
1110 nf_conntrack_cachep
= kmem_cache_create("nf_conntrack",
1111 sizeof(struct nf_conn
),
1113 if (!nf_conntrack_cachep
) {
1114 printk(KERN_ERR
"Unable to create nf_conn slab cache\n");
1118 ret
= nf_conntrack_proto_init();
1120 goto err_free_conntrack_slab
;
1122 ret
= nf_conntrack_expect_init();
1124 goto out_fini_proto
;
1126 ret
= nf_conntrack_helper_init();
1128 goto out_fini_expect
;
1130 /* For use by REJECT target */
1131 rcu_assign_pointer(ip_ct_attach
, __nf_conntrack_attach
);
1132 rcu_assign_pointer(nf_ct_destroy
, destroy_conntrack
);
1134 /* Set up fake conntrack:
1135 - to never be deleted, not in any hashes */
1136 atomic_set(&nf_conntrack_untracked
.ct_general
.use
, 1);
1137 /* - and look it like as a confirmed connection */
1138 set_bit(IPS_CONFIRMED_BIT
, &nf_conntrack_untracked
.status
);
1143 nf_conntrack_expect_fini();
1145 nf_conntrack_proto_fini();
1146 err_free_conntrack_slab
:
1147 kmem_cache_destroy(nf_conntrack_cachep
);
1149 nf_ct_free_hashtable(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1150 nf_conntrack_htable_size
);