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_SPINLOCK(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
;
67 DEFINE_PER_CPU(struct ip_conntrack_stat
, nf_conntrack_stat
);
68 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat
);
70 static int nf_conntrack_hash_rnd_initted
;
71 static unsigned int nf_conntrack_hash_rnd
;
73 static u_int32_t
__hash_conntrack(const struct nf_conntrack_tuple
*tuple
,
74 unsigned int size
, unsigned int rnd
)
79 /* The direction must be ignored, so we hash everything up to the
80 * destination ports (which is a multiple of 4) and treat the last
81 * three bytes manually.
83 n
= (sizeof(tuple
->src
) + sizeof(tuple
->dst
.u3
)) / sizeof(u32
);
84 h
= jhash2((u32
*)tuple
, n
,
85 rnd
^ (((__force __u16
)tuple
->dst
.u
.all
<< 16) |
86 tuple
->dst
.protonum
));
88 return ((u64
)h
* size
) >> 32;
91 static inline u_int32_t
hash_conntrack(const struct nf_conntrack_tuple
*tuple
)
93 return __hash_conntrack(tuple
, nf_conntrack_htable_size
,
94 nf_conntrack_hash_rnd
);
98 nf_ct_get_tuple(const struct sk_buff
*skb
,
100 unsigned int dataoff
,
103 struct nf_conntrack_tuple
*tuple
,
104 const struct nf_conntrack_l3proto
*l3proto
,
105 const struct nf_conntrack_l4proto
*l4proto
)
107 NF_CT_TUPLE_U_BLANK(tuple
);
109 tuple
->src
.l3num
= l3num
;
110 if (l3proto
->pkt_to_tuple(skb
, nhoff
, tuple
) == 0)
113 tuple
->dst
.protonum
= protonum
;
114 tuple
->dst
.dir
= IP_CT_DIR_ORIGINAL
;
116 return l4proto
->pkt_to_tuple(skb
, dataoff
, tuple
);
118 EXPORT_SYMBOL_GPL(nf_ct_get_tuple
);
120 bool nf_ct_get_tuplepr(const struct sk_buff
*skb
, unsigned int nhoff
,
121 u_int16_t l3num
, struct nf_conntrack_tuple
*tuple
)
123 struct nf_conntrack_l3proto
*l3proto
;
124 struct nf_conntrack_l4proto
*l4proto
;
125 unsigned int protoff
;
131 l3proto
= __nf_ct_l3proto_find(l3num
);
132 ret
= l3proto
->get_l4proto(skb
, nhoff
, &protoff
, &protonum
);
133 if (ret
!= NF_ACCEPT
) {
138 l4proto
= __nf_ct_l4proto_find(l3num
, protonum
);
140 ret
= nf_ct_get_tuple(skb
, nhoff
, protoff
, l3num
, protonum
, tuple
,
146 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr
);
149 nf_ct_invert_tuple(struct nf_conntrack_tuple
*inverse
,
150 const struct nf_conntrack_tuple
*orig
,
151 const struct nf_conntrack_l3proto
*l3proto
,
152 const struct nf_conntrack_l4proto
*l4proto
)
154 NF_CT_TUPLE_U_BLANK(inverse
);
156 inverse
->src
.l3num
= orig
->src
.l3num
;
157 if (l3proto
->invert_tuple(inverse
, orig
) == 0)
160 inverse
->dst
.dir
= !orig
->dst
.dir
;
162 inverse
->dst
.protonum
= orig
->dst
.protonum
;
163 return l4proto
->invert_tuple(inverse
, orig
);
165 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple
);
168 clean_from_lists(struct nf_conn
*ct
)
170 pr_debug("clean_from_lists(%p)\n", ct
);
171 hlist_del_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
);
172 hlist_del_rcu(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnode
);
174 /* Destroy all pending expectations */
175 nf_ct_remove_expectations(ct
);
179 destroy_conntrack(struct nf_conntrack
*nfct
)
181 struct nf_conn
*ct
= (struct nf_conn
*)nfct
;
182 struct nf_conntrack_l4proto
*l4proto
;
184 pr_debug("destroy_conntrack(%p)\n", ct
);
185 NF_CT_ASSERT(atomic_read(&nfct
->use
) == 0);
186 NF_CT_ASSERT(!timer_pending(&ct
->timeout
));
188 nf_conntrack_event(IPCT_DESTROY
, ct
);
189 set_bit(IPS_DYING_BIT
, &ct
->status
);
191 /* To make sure we don't get any weird locking issues here:
192 * destroy_conntrack() MUST NOT be called with a write lock
193 * to nf_conntrack_lock!!! -HW */
195 l4proto
= __nf_ct_l4proto_find(nf_ct_l3num(ct
), nf_ct_protonum(ct
));
196 if (l4proto
&& l4proto
->destroy
)
197 l4proto
->destroy(ct
);
199 nf_ct_ext_destroy(ct
);
203 spin_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 spin_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 spin_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 spin_unlock_bh(&nf_conntrack_lock
);
249 struct nf_conntrack_tuple_hash
*
250 __nf_conntrack_find(const struct nf_conntrack_tuple
*tuple
)
252 struct nf_conntrack_tuple_hash
*h
;
253 struct hlist_node
*n
;
254 unsigned int hash
= hash_conntrack(tuple
);
256 /* Disable BHs the entire time since we normally need to disable them
257 * at least once for the stats anyway.
260 hlist_for_each_entry_rcu(h
, n
, &nf_conntrack_hash
[hash
], hnode
) {
261 if (nf_ct_tuple_equal(tuple
, &h
->tuple
)) {
262 NF_CT_STAT_INC(found
);
266 NF_CT_STAT_INC(searched
);
272 EXPORT_SYMBOL_GPL(__nf_conntrack_find
);
274 /* Find a connection corresponding to a tuple. */
275 struct nf_conntrack_tuple_hash
*
276 nf_conntrack_find_get(const struct nf_conntrack_tuple
*tuple
)
278 struct nf_conntrack_tuple_hash
*h
;
282 h
= __nf_conntrack_find(tuple
);
284 ct
= nf_ct_tuplehash_to_ctrack(h
);
285 if (unlikely(!atomic_inc_not_zero(&ct
->ct_general
.use
)))
292 EXPORT_SYMBOL_GPL(nf_conntrack_find_get
);
294 static void __nf_conntrack_hash_insert(struct nf_conn
*ct
,
296 unsigned int repl_hash
)
298 hlist_add_head_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
,
299 &nf_conntrack_hash
[hash
]);
300 hlist_add_head_rcu(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnode
,
301 &nf_conntrack_hash
[repl_hash
]);
304 void nf_conntrack_hash_insert(struct nf_conn
*ct
)
306 unsigned int hash
, repl_hash
;
308 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
309 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
311 spin_lock_bh(&nf_conntrack_lock
);
312 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
313 spin_unlock_bh(&nf_conntrack_lock
);
315 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert
);
317 /* Confirm a connection given skb; places it in hash table */
319 __nf_conntrack_confirm(struct sk_buff
*skb
)
321 unsigned int hash
, repl_hash
;
322 struct nf_conntrack_tuple_hash
*h
;
324 struct nf_conn_help
*help
;
325 struct hlist_node
*n
;
326 enum ip_conntrack_info ctinfo
;
328 ct
= nf_ct_get(skb
, &ctinfo
);
330 /* ipt_REJECT uses nf_conntrack_attach to attach related
331 ICMP/TCP RST packets in other direction. Actual packet
332 which created connection will be IP_CT_NEW or for an
333 expected connection, IP_CT_RELATED. */
334 if (CTINFO2DIR(ctinfo
) != IP_CT_DIR_ORIGINAL
)
337 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
338 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
340 /* We're not in hash table, and we refuse to set up related
341 connections for unconfirmed conns. But packet copies and
342 REJECT will give spurious warnings here. */
343 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
345 /* No external references means noone else could have
347 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
348 pr_debug("Confirming conntrack %p\n", ct
);
350 spin_lock_bh(&nf_conntrack_lock
);
352 /* See if there's one in the list already, including reverse:
353 NAT could have grabbed it without realizing, since we're
354 not in the hash. If there is, we lost race. */
355 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[hash
], hnode
)
356 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
359 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[repl_hash
], hnode
)
360 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
364 /* Remove from unconfirmed list */
365 hlist_del(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
);
367 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
368 /* Timer relative to confirmation time, not original
369 setting time, otherwise we'd get timer wrap in
370 weird delay cases. */
371 ct
->timeout
.expires
+= jiffies
;
372 add_timer(&ct
->timeout
);
373 atomic_inc(&ct
->ct_general
.use
);
374 set_bit(IPS_CONFIRMED_BIT
, &ct
->status
);
375 NF_CT_STAT_INC(insert
);
376 spin_unlock_bh(&nf_conntrack_lock
);
377 help
= nfct_help(ct
);
378 if (help
&& help
->helper
)
379 nf_conntrack_event_cache(IPCT_HELPER
, skb
);
380 #ifdef CONFIG_NF_NAT_NEEDED
381 if (test_bit(IPS_SRC_NAT_DONE_BIT
, &ct
->status
) ||
382 test_bit(IPS_DST_NAT_DONE_BIT
, &ct
->status
))
383 nf_conntrack_event_cache(IPCT_NATINFO
, skb
);
385 nf_conntrack_event_cache(master_ct(ct
) ?
386 IPCT_RELATED
: IPCT_NEW
, skb
);
390 NF_CT_STAT_INC(insert_failed
);
391 spin_unlock_bh(&nf_conntrack_lock
);
394 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm
);
396 /* Returns true if a connection correspondings to the tuple (required
399 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple
*tuple
,
400 const struct nf_conn
*ignored_conntrack
)
402 struct nf_conntrack_tuple_hash
*h
;
403 struct hlist_node
*n
;
404 unsigned int hash
= hash_conntrack(tuple
);
406 /* Disable BHs the entire time since we need to disable them at
407 * least once for the stats anyway.
410 hlist_for_each_entry_rcu(h
, n
, &nf_conntrack_hash
[hash
], hnode
) {
411 if (nf_ct_tuplehash_to_ctrack(h
) != ignored_conntrack
&&
412 nf_ct_tuple_equal(tuple
, &h
->tuple
)) {
413 NF_CT_STAT_INC(found
);
414 rcu_read_unlock_bh();
417 NF_CT_STAT_INC(searched
);
419 rcu_read_unlock_bh();
423 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken
);
425 #define NF_CT_EVICTION_RANGE 8
427 /* There's a small race here where we may free a just-assured
428 connection. Too bad: we're in trouble anyway. */
429 static noinline
int early_drop(unsigned int hash
)
431 /* Use oldest entry, which is roughly LRU */
432 struct nf_conntrack_tuple_hash
*h
;
433 struct nf_conn
*ct
= NULL
, *tmp
;
434 struct hlist_node
*n
;
435 unsigned int i
, cnt
= 0;
439 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
440 hlist_for_each_entry_rcu(h
, n
, &nf_conntrack_hash
[hash
],
442 tmp
= nf_ct_tuplehash_to_ctrack(h
);
443 if (!test_bit(IPS_ASSURED_BIT
, &tmp
->status
))
448 if (ct
&& unlikely(!atomic_inc_not_zero(&ct
->ct_general
.use
)))
450 if (ct
|| cnt
>= NF_CT_EVICTION_RANGE
)
452 hash
= (hash
+ 1) % nf_conntrack_htable_size
;
459 if (del_timer(&ct
->timeout
)) {
460 death_by_timeout((unsigned long)ct
);
462 NF_CT_STAT_INC_ATOMIC(early_drop
);
468 struct nf_conn
*nf_conntrack_alloc(const struct nf_conntrack_tuple
*orig
,
469 const struct nf_conntrack_tuple
*repl
)
471 struct nf_conn
*ct
= NULL
;
473 if (unlikely(!nf_conntrack_hash_rnd_initted
)) {
474 get_random_bytes(&nf_conntrack_hash_rnd
, 4);
475 nf_conntrack_hash_rnd_initted
= 1;
478 /* We don't want any race condition at early drop stage */
479 atomic_inc(&nf_conntrack_count
);
481 if (nf_conntrack_max
&&
482 unlikely(atomic_read(&nf_conntrack_count
) > nf_conntrack_max
)) {
483 unsigned int hash
= hash_conntrack(orig
);
484 if (!early_drop(hash
)) {
485 atomic_dec(&nf_conntrack_count
);
488 "nf_conntrack: table full, dropping"
490 return ERR_PTR(-ENOMEM
);
494 ct
= kmem_cache_zalloc(nf_conntrack_cachep
, GFP_ATOMIC
);
496 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
497 atomic_dec(&nf_conntrack_count
);
498 return ERR_PTR(-ENOMEM
);
501 atomic_set(&ct
->ct_general
.use
, 1);
502 ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
= *orig
;
503 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *repl
;
504 /* Don't set timer yet: wait for confirmation */
505 setup_timer(&ct
->timeout
, death_by_timeout
, (unsigned long)ct
);
506 INIT_RCU_HEAD(&ct
->rcu
);
510 EXPORT_SYMBOL_GPL(nf_conntrack_alloc
);
512 static void nf_conntrack_free_rcu(struct rcu_head
*head
)
514 struct nf_conn
*ct
= container_of(head
, struct nf_conn
, rcu
);
517 kmem_cache_free(nf_conntrack_cachep
, ct
);
518 atomic_dec(&nf_conntrack_count
);
521 void nf_conntrack_free(struct nf_conn
*ct
)
523 call_rcu(&ct
->rcu
, nf_conntrack_free_rcu
);
525 EXPORT_SYMBOL_GPL(nf_conntrack_free
);
527 /* Allocate a new conntrack: we return -ENOMEM if classification
528 failed due to stress. Otherwise it really is unclassifiable. */
529 static struct nf_conntrack_tuple_hash
*
530 init_conntrack(const struct nf_conntrack_tuple
*tuple
,
531 struct nf_conntrack_l3proto
*l3proto
,
532 struct nf_conntrack_l4proto
*l4proto
,
534 unsigned int dataoff
)
537 struct nf_conn_help
*help
;
538 struct nf_conntrack_tuple repl_tuple
;
539 struct nf_conntrack_expect
*exp
;
541 if (!nf_ct_invert_tuple(&repl_tuple
, tuple
, l3proto
, l4proto
)) {
542 pr_debug("Can't invert tuple.\n");
546 ct
= nf_conntrack_alloc(tuple
, &repl_tuple
);
547 if (ct
== NULL
|| IS_ERR(ct
)) {
548 pr_debug("Can't allocate conntrack.\n");
549 return (struct nf_conntrack_tuple_hash
*)ct
;
552 if (!l4proto
->new(ct
, skb
, dataoff
)) {
553 nf_conntrack_free(ct
);
554 pr_debug("init conntrack: can't track with proto module\n");
558 spin_lock_bh(&nf_conntrack_lock
);
559 exp
= nf_ct_find_expectation(tuple
);
561 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
563 /* Welcome, Mr. Bond. We've been expecting you... */
564 __set_bit(IPS_EXPECTED_BIT
, &ct
->status
);
565 ct
->master
= exp
->master
;
567 help
= nf_ct_helper_ext_add(ct
, GFP_ATOMIC
);
569 rcu_assign_pointer(help
->helper
, exp
->helper
);
572 #ifdef CONFIG_NF_CONNTRACK_MARK
573 ct
->mark
= exp
->master
->mark
;
575 #ifdef CONFIG_NF_CONNTRACK_SECMARK
576 ct
->secmark
= exp
->master
->secmark
;
578 nf_conntrack_get(&ct
->master
->ct_general
);
579 NF_CT_STAT_INC(expect_new
);
581 struct nf_conntrack_helper
*helper
;
583 helper
= __nf_ct_helper_find(&repl_tuple
);
585 help
= nf_ct_helper_ext_add(ct
, GFP_ATOMIC
);
587 rcu_assign_pointer(help
->helper
, helper
);
592 /* Overload tuple linked list to put us in unconfirmed list. */
593 hlist_add_head(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnode
, &unconfirmed
);
595 spin_unlock_bh(&nf_conntrack_lock
);
599 exp
->expectfn(ct
, exp
);
600 nf_ct_expect_put(exp
);
603 return &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
];
606 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
607 static inline struct nf_conn
*
608 resolve_normal_ct(struct sk_buff
*skb
,
609 unsigned int dataoff
,
612 struct nf_conntrack_l3proto
*l3proto
,
613 struct nf_conntrack_l4proto
*l4proto
,
615 enum ip_conntrack_info
*ctinfo
)
617 struct nf_conntrack_tuple tuple
;
618 struct nf_conntrack_tuple_hash
*h
;
621 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
),
622 dataoff
, l3num
, protonum
, &tuple
, l3proto
,
624 pr_debug("resolve_normal_ct: Can't get tuple\n");
628 /* look for tuple match */
629 h
= nf_conntrack_find_get(&tuple
);
631 h
= init_conntrack(&tuple
, l3proto
, l4proto
, skb
, dataoff
);
637 ct
= nf_ct_tuplehash_to_ctrack(h
);
639 /* It exists; we have (non-exclusive) reference. */
640 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
) {
641 *ctinfo
= IP_CT_ESTABLISHED
+ IP_CT_IS_REPLY
;
642 /* Please set reply bit if this packet OK */
645 /* Once we've had two way comms, always ESTABLISHED. */
646 if (test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
647 pr_debug("nf_conntrack_in: normal packet for %p\n", ct
);
648 *ctinfo
= IP_CT_ESTABLISHED
;
649 } else if (test_bit(IPS_EXPECTED_BIT
, &ct
->status
)) {
650 pr_debug("nf_conntrack_in: related packet for %p\n",
652 *ctinfo
= IP_CT_RELATED
;
654 pr_debug("nf_conntrack_in: new packet for %p\n", ct
);
659 skb
->nfct
= &ct
->ct_general
;
660 skb
->nfctinfo
= *ctinfo
;
665 nf_conntrack_in(int pf
, unsigned int hooknum
, struct sk_buff
*skb
)
668 enum ip_conntrack_info ctinfo
;
669 struct nf_conntrack_l3proto
*l3proto
;
670 struct nf_conntrack_l4proto
*l4proto
;
671 unsigned int dataoff
;
676 /* Previously seen (loopback or untracked)? Ignore. */
678 NF_CT_STAT_INC_ATOMIC(ignore
);
682 /* rcu_read_lock()ed by nf_hook_slow */
683 l3proto
= __nf_ct_l3proto_find((u_int16_t
)pf
);
684 ret
= l3proto
->get_l4proto(skb
, skb_network_offset(skb
),
685 &dataoff
, &protonum
);
687 pr_debug("not prepared to track yet or error occured\n");
688 NF_CT_STAT_INC_ATOMIC(error
);
689 NF_CT_STAT_INC_ATOMIC(invalid
);
693 l4proto
= __nf_ct_l4proto_find((u_int16_t
)pf
, protonum
);
695 /* It may be an special packet, error, unclean...
696 * inverse of the return code tells to the netfilter
697 * core what to do with the packet. */
698 if (l4proto
->error
!= NULL
&&
699 (ret
= l4proto
->error(skb
, dataoff
, &ctinfo
, pf
, hooknum
)) <= 0) {
700 NF_CT_STAT_INC_ATOMIC(error
);
701 NF_CT_STAT_INC_ATOMIC(invalid
);
705 ct
= resolve_normal_ct(skb
, dataoff
, pf
, protonum
, l3proto
, l4proto
,
706 &set_reply
, &ctinfo
);
708 /* Not valid part of a connection */
709 NF_CT_STAT_INC_ATOMIC(invalid
);
714 /* Too stressed to deal. */
715 NF_CT_STAT_INC_ATOMIC(drop
);
719 NF_CT_ASSERT(skb
->nfct
);
721 ret
= l4proto
->packet(ct
, skb
, dataoff
, ctinfo
, pf
, hooknum
);
723 /* Invalid: inverse of the return code tells
724 * the netfilter core what to do */
725 pr_debug("nf_conntrack_in: Can't track with proto module\n");
726 nf_conntrack_put(skb
->nfct
);
728 NF_CT_STAT_INC_ATOMIC(invalid
);
732 if (set_reply
&& !test_and_set_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
))
733 nf_conntrack_event_cache(IPCT_STATUS
, skb
);
737 EXPORT_SYMBOL_GPL(nf_conntrack_in
);
739 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple
*inverse
,
740 const struct nf_conntrack_tuple
*orig
)
745 ret
= nf_ct_invert_tuple(inverse
, orig
,
746 __nf_ct_l3proto_find(orig
->src
.l3num
),
747 __nf_ct_l4proto_find(orig
->src
.l3num
,
748 orig
->dst
.protonum
));
752 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr
);
754 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
755 implicitly racy: see __nf_conntrack_confirm */
756 void nf_conntrack_alter_reply(struct nf_conn
*ct
,
757 const struct nf_conntrack_tuple
*newreply
)
759 struct nf_conn_help
*help
= nfct_help(ct
);
760 struct nf_conntrack_helper
*helper
;
762 /* Should be unconfirmed, so not in hash table yet */
763 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
765 pr_debug("Altering reply tuple of %p to ", ct
);
766 nf_ct_dump_tuple(newreply
);
768 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *newreply
;
769 if (ct
->master
|| (help
&& !hlist_empty(&help
->expectations
)))
773 helper
= __nf_ct_helper_find(newreply
);
774 if (helper
== NULL
) {
776 rcu_assign_pointer(help
->helper
, NULL
);
781 help
= nf_ct_helper_ext_add(ct
, GFP_ATOMIC
);
785 memset(&help
->help
, 0, sizeof(help
->help
));
788 rcu_assign_pointer(help
->helper
, helper
);
792 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply
);
794 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
795 void __nf_ct_refresh_acct(struct nf_conn
*ct
,
796 enum ip_conntrack_info ctinfo
,
797 const struct sk_buff
*skb
,
798 unsigned long extra_jiffies
,
803 NF_CT_ASSERT(ct
->timeout
.data
== (unsigned long)ct
);
806 spin_lock_bh(&nf_conntrack_lock
);
808 /* Only update if this is not a fixed timeout */
809 if (test_bit(IPS_FIXED_TIMEOUT_BIT
, &ct
->status
))
812 /* If not in hash table, timer will not be active yet */
813 if (!nf_ct_is_confirmed(ct
)) {
814 ct
->timeout
.expires
= extra_jiffies
;
815 event
= IPCT_REFRESH
;
817 unsigned long newtime
= jiffies
+ extra_jiffies
;
819 /* Only update the timeout if the new timeout is at least
820 HZ jiffies from the old timeout. Need del_timer for race
821 avoidance (may already be dying). */
822 if (newtime
- ct
->timeout
.expires
>= HZ
823 && del_timer(&ct
->timeout
)) {
824 ct
->timeout
.expires
= newtime
;
825 add_timer(&ct
->timeout
);
826 event
= IPCT_REFRESH
;
831 #ifdef CONFIG_NF_CT_ACCT
833 ct
->counters
[CTINFO2DIR(ctinfo
)].packets
++;
834 ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
+=
835 skb
->len
- skb_network_offset(skb
);
837 if ((ct
->counters
[CTINFO2DIR(ctinfo
)].packets
& 0x80000000)
838 || (ct
->counters
[CTINFO2DIR(ctinfo
)].bytes
& 0x80000000))
839 event
|= IPCT_COUNTER_FILLING
;
843 spin_unlock_bh(&nf_conntrack_lock
);
845 /* must be unlocked when calling event cache */
847 nf_conntrack_event_cache(event
, skb
);
849 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct
);
851 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
853 #include <linux/netfilter/nfnetlink.h>
854 #include <linux/netfilter/nfnetlink_conntrack.h>
855 #include <linux/mutex.h>
857 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
858 * in ip_conntrack_core, since we don't want the protocols to autoload
859 * or depend on ctnetlink */
860 int nf_ct_port_tuple_to_nlattr(struct sk_buff
*skb
,
861 const struct nf_conntrack_tuple
*tuple
)
863 NLA_PUT_BE16(skb
, CTA_PROTO_SRC_PORT
, tuple
->src
.u
.tcp
.port
);
864 NLA_PUT_BE16(skb
, CTA_PROTO_DST_PORT
, tuple
->dst
.u
.tcp
.port
);
870 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr
);
872 const struct nla_policy nf_ct_port_nla_policy
[CTA_PROTO_MAX
+1] = {
873 [CTA_PROTO_SRC_PORT
] = { .type
= NLA_U16
},
874 [CTA_PROTO_DST_PORT
] = { .type
= NLA_U16
},
876 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy
);
878 int nf_ct_port_nlattr_to_tuple(struct nlattr
*tb
[],
879 struct nf_conntrack_tuple
*t
)
881 if (!tb
[CTA_PROTO_SRC_PORT
] || !tb
[CTA_PROTO_DST_PORT
])
884 t
->src
.u
.tcp
.port
= nla_get_be16(tb
[CTA_PROTO_SRC_PORT
]);
885 t
->dst
.u
.tcp
.port
= nla_get_be16(tb
[CTA_PROTO_DST_PORT
]);
889 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple
);
892 /* Used by ipt_REJECT and ip6t_REJECT. */
893 static void nf_conntrack_attach(struct sk_buff
*nskb
, struct sk_buff
*skb
)
896 enum ip_conntrack_info ctinfo
;
898 /* This ICMP is in reverse direction to the packet which caused it */
899 ct
= nf_ct_get(skb
, &ctinfo
);
900 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
)
901 ctinfo
= IP_CT_RELATED
+ IP_CT_IS_REPLY
;
903 ctinfo
= IP_CT_RELATED
;
905 /* Attach to new skbuff, and increment count */
906 nskb
->nfct
= &ct
->ct_general
;
907 nskb
->nfctinfo
= ctinfo
;
908 nf_conntrack_get(nskb
->nfct
);
911 /* Bring out ya dead! */
912 static struct nf_conn
*
913 get_next_corpse(int (*iter
)(struct nf_conn
*i
, void *data
),
914 void *data
, unsigned int *bucket
)
916 struct nf_conntrack_tuple_hash
*h
;
918 struct hlist_node
*n
;
920 spin_lock_bh(&nf_conntrack_lock
);
921 for (; *bucket
< nf_conntrack_htable_size
; (*bucket
)++) {
922 hlist_for_each_entry(h
, n
, &nf_conntrack_hash
[*bucket
], hnode
) {
923 ct
= nf_ct_tuplehash_to_ctrack(h
);
928 hlist_for_each_entry(h
, n
, &unconfirmed
, hnode
) {
929 ct
= nf_ct_tuplehash_to_ctrack(h
);
931 set_bit(IPS_DYING_BIT
, &ct
->status
);
933 spin_unlock_bh(&nf_conntrack_lock
);
936 atomic_inc(&ct
->ct_general
.use
);
937 spin_unlock_bh(&nf_conntrack_lock
);
942 nf_ct_iterate_cleanup(int (*iter
)(struct nf_conn
*i
, void *data
), void *data
)
945 unsigned int bucket
= 0;
947 while ((ct
= get_next_corpse(iter
, data
, &bucket
)) != NULL
) {
948 /* Time to push up daises... */
949 if (del_timer(&ct
->timeout
))
950 death_by_timeout((unsigned long)ct
);
951 /* ... else the timer will get him soon. */
956 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup
);
958 static int kill_all(struct nf_conn
*i
, void *data
)
963 void nf_ct_free_hashtable(struct hlist_head
*hash
, int vmalloced
, unsigned int size
)
968 free_pages((unsigned long)hash
,
969 get_order(sizeof(struct hlist_head
) * size
));
971 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable
);
973 void nf_conntrack_flush(void)
975 nf_ct_iterate_cleanup(kill_all
, NULL
);
977 EXPORT_SYMBOL_GPL(nf_conntrack_flush
);
979 /* Mishearing the voices in his head, our hero wonders how he's
980 supposed to kill the mall. */
981 void nf_conntrack_cleanup(void)
983 rcu_assign_pointer(ip_ct_attach
, NULL
);
985 /* This makes sure all current packets have passed through
986 netfilter framework. Roll on, two-stage module
990 nf_ct_event_cache_flush();
992 nf_conntrack_flush();
993 if (atomic_read(&nf_conntrack_count
) != 0) {
995 goto i_see_dead_people
;
997 /* wait until all references to nf_conntrack_untracked are dropped */
998 while (atomic_read(&nf_conntrack_untracked
.ct_general
.use
) > 1)
1001 rcu_assign_pointer(nf_ct_destroy
, NULL
);
1003 kmem_cache_destroy(nf_conntrack_cachep
);
1004 nf_ct_free_hashtable(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1005 nf_conntrack_htable_size
);
1007 nf_conntrack_proto_fini();
1008 nf_conntrack_helper_fini();
1009 nf_conntrack_expect_fini();
1012 struct hlist_head
*nf_ct_alloc_hashtable(unsigned int *sizep
, int *vmalloced
)
1014 struct hlist_head
*hash
;
1015 unsigned int size
, i
;
1019 size
= *sizep
= roundup(*sizep
, PAGE_SIZE
/ sizeof(struct hlist_head
));
1020 hash
= (void*)__get_free_pages(GFP_KERNEL
|__GFP_NOWARN
,
1021 get_order(sizeof(struct hlist_head
)
1025 printk(KERN_WARNING
"nf_conntrack: falling back to vmalloc.\n");
1026 hash
= vmalloc(sizeof(struct hlist_head
) * size
);
1030 for (i
= 0; i
< size
; i
++)
1031 INIT_HLIST_HEAD(&hash
[i
]);
1035 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable
);
1037 int nf_conntrack_set_hashsize(const char *val
, struct kernel_param
*kp
)
1039 int i
, bucket
, vmalloced
, old_vmalloced
;
1040 unsigned int hashsize
, old_size
;
1042 struct hlist_head
*hash
, *old_hash
;
1043 struct nf_conntrack_tuple_hash
*h
;
1045 /* On boot, we can set this without any fancy locking. */
1046 if (!nf_conntrack_htable_size
)
1047 return param_set_uint(val
, kp
);
1049 hashsize
= simple_strtoul(val
, NULL
, 0);
1053 hash
= nf_ct_alloc_hashtable(&hashsize
, &vmalloced
);
1057 /* We have to rehahs for the new table anyway, so we also can
1058 * use a newrandom seed */
1059 get_random_bytes(&rnd
, 4);
1061 /* Lookups in the old hash might happen in parallel, which means we
1062 * might get false negatives during connection lookup. New connections
1063 * created because of a false negative won't make it into the hash
1064 * though since that required taking the lock.
1066 spin_lock_bh(&nf_conntrack_lock
);
1067 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
1068 while (!hlist_empty(&nf_conntrack_hash
[i
])) {
1069 h
= hlist_entry(nf_conntrack_hash
[i
].first
,
1070 struct nf_conntrack_tuple_hash
, hnode
);
1071 hlist_del_rcu(&h
->hnode
);
1072 bucket
= __hash_conntrack(&h
->tuple
, hashsize
, rnd
);
1073 hlist_add_head(&h
->hnode
, &hash
[bucket
]);
1076 old_size
= nf_conntrack_htable_size
;
1077 old_vmalloced
= nf_conntrack_vmalloc
;
1078 old_hash
= nf_conntrack_hash
;
1080 nf_conntrack_htable_size
= hashsize
;
1081 nf_conntrack_vmalloc
= vmalloced
;
1082 nf_conntrack_hash
= hash
;
1083 nf_conntrack_hash_rnd
= rnd
;
1084 spin_unlock_bh(&nf_conntrack_lock
);
1086 nf_ct_free_hashtable(old_hash
, old_vmalloced
, old_size
);
1089 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize
);
1091 module_param_call(hashsize
, nf_conntrack_set_hashsize
, param_get_uint
,
1092 &nf_conntrack_htable_size
, 0600);
1094 int __init
nf_conntrack_init(void)
1099 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1100 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1101 if (!nf_conntrack_htable_size
) {
1102 nf_conntrack_htable_size
1103 = (((num_physpages
<< PAGE_SHIFT
) / 16384)
1104 / sizeof(struct hlist_head
));
1105 if (num_physpages
> (1024 * 1024 * 1024 / PAGE_SIZE
))
1106 nf_conntrack_htable_size
= 16384;
1107 if (nf_conntrack_htable_size
< 32)
1108 nf_conntrack_htable_size
= 32;
1110 /* Use a max. factor of four by default to get the same max as
1111 * with the old struct list_heads. When a table size is given
1112 * we use the old value of 8 to avoid reducing the max.
1116 nf_conntrack_hash
= nf_ct_alloc_hashtable(&nf_conntrack_htable_size
,
1117 &nf_conntrack_vmalloc
);
1118 if (!nf_conntrack_hash
) {
1119 printk(KERN_ERR
"Unable to create nf_conntrack_hash\n");
1123 nf_conntrack_max
= max_factor
* nf_conntrack_htable_size
;
1125 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1126 NF_CONNTRACK_VERSION
, nf_conntrack_htable_size
,
1129 nf_conntrack_cachep
= kmem_cache_create("nf_conntrack",
1130 sizeof(struct nf_conn
),
1132 if (!nf_conntrack_cachep
) {
1133 printk(KERN_ERR
"Unable to create nf_conn slab cache\n");
1137 ret
= nf_conntrack_proto_init();
1139 goto err_free_conntrack_slab
;
1141 ret
= nf_conntrack_expect_init();
1143 goto out_fini_proto
;
1145 ret
= nf_conntrack_helper_init();
1147 goto out_fini_expect
;
1149 /* For use by REJECT target */
1150 rcu_assign_pointer(ip_ct_attach
, nf_conntrack_attach
);
1151 rcu_assign_pointer(nf_ct_destroy
, destroy_conntrack
);
1153 /* Set up fake conntrack:
1154 - to never be deleted, not in any hashes */
1155 atomic_set(&nf_conntrack_untracked
.ct_general
.use
, 1);
1156 /* - and look it like as a confirmed connection */
1157 set_bit(IPS_CONFIRMED_BIT
, &nf_conntrack_untracked
.status
);
1162 nf_conntrack_expect_fini();
1164 nf_conntrack_proto_fini();
1165 err_free_conntrack_slab
:
1166 kmem_cache_destroy(nf_conntrack_cachep
);
1168 nf_ct_free_hashtable(nf_conntrack_hash
, nf_conntrack_vmalloc
,
1169 nf_conntrack_htable_size
);