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>
32 #include <linux/rculist_nulls.h>
34 #include <net/netfilter/nf_conntrack.h>
35 #include <net/netfilter/nf_conntrack_l3proto.h>
36 #include <net/netfilter/nf_conntrack_l4proto.h>
37 #include <net/netfilter/nf_conntrack_expect.h>
38 #include <net/netfilter/nf_conntrack_helper.h>
39 #include <net/netfilter/nf_conntrack_core.h>
40 #include <net/netfilter/nf_conntrack_extend.h>
41 #include <net/netfilter/nf_conntrack_acct.h>
42 #include <net/netfilter/nf_nat.h>
43 #include <net/netfilter/nf_nat_core.h>
45 #define NF_CONNTRACK_VERSION "0.5.0"
47 int (*nfnetlink_parse_nat_setup_hook
)(struct nf_conn
*ct
,
48 enum nf_nat_manip_type manip
,
49 struct nlattr
*attr
) __read_mostly
;
50 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook
);
52 DEFINE_SPINLOCK(nf_conntrack_lock
);
53 EXPORT_SYMBOL_GPL(nf_conntrack_lock
);
55 unsigned int nf_conntrack_htable_size __read_mostly
;
56 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size
);
58 unsigned int nf_conntrack_max __read_mostly
;
59 EXPORT_SYMBOL_GPL(nf_conntrack_max
);
61 struct nf_conn nf_conntrack_untracked __read_mostly
;
62 EXPORT_SYMBOL_GPL(nf_conntrack_untracked
);
64 static struct kmem_cache
*nf_conntrack_cachep __read_mostly
;
66 static int nf_conntrack_hash_rnd_initted
;
67 static unsigned int nf_conntrack_hash_rnd
;
69 static u_int32_t
__hash_conntrack(const struct nf_conntrack_tuple
*tuple
,
70 unsigned int size
, unsigned int rnd
)
75 /* The direction must be ignored, so we hash everything up to the
76 * destination ports (which is a multiple of 4) and treat the last
77 * three bytes manually.
79 n
= (sizeof(tuple
->src
) + sizeof(tuple
->dst
.u3
)) / sizeof(u32
);
80 h
= jhash2((u32
*)tuple
, n
,
81 rnd
^ (((__force __u16
)tuple
->dst
.u
.all
<< 16) |
82 tuple
->dst
.protonum
));
84 return ((u64
)h
* size
) >> 32;
87 static inline u_int32_t
hash_conntrack(const struct nf_conntrack_tuple
*tuple
)
89 return __hash_conntrack(tuple
, nf_conntrack_htable_size
,
90 nf_conntrack_hash_rnd
);
94 nf_ct_get_tuple(const struct sk_buff
*skb
,
99 struct nf_conntrack_tuple
*tuple
,
100 const struct nf_conntrack_l3proto
*l3proto
,
101 const struct nf_conntrack_l4proto
*l4proto
)
103 memset(tuple
, 0, sizeof(*tuple
));
105 tuple
->src
.l3num
= l3num
;
106 if (l3proto
->pkt_to_tuple(skb
, nhoff
, tuple
) == 0)
109 tuple
->dst
.protonum
= protonum
;
110 tuple
->dst
.dir
= IP_CT_DIR_ORIGINAL
;
112 return l4proto
->pkt_to_tuple(skb
, dataoff
, tuple
);
114 EXPORT_SYMBOL_GPL(nf_ct_get_tuple
);
116 bool nf_ct_get_tuplepr(const struct sk_buff
*skb
, unsigned int nhoff
,
117 u_int16_t l3num
, struct nf_conntrack_tuple
*tuple
)
119 struct nf_conntrack_l3proto
*l3proto
;
120 struct nf_conntrack_l4proto
*l4proto
;
121 unsigned int protoff
;
127 l3proto
= __nf_ct_l3proto_find(l3num
);
128 ret
= l3proto
->get_l4proto(skb
, nhoff
, &protoff
, &protonum
);
129 if (ret
!= NF_ACCEPT
) {
134 l4proto
= __nf_ct_l4proto_find(l3num
, protonum
);
136 ret
= nf_ct_get_tuple(skb
, nhoff
, protoff
, l3num
, protonum
, tuple
,
142 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr
);
145 nf_ct_invert_tuple(struct nf_conntrack_tuple
*inverse
,
146 const struct nf_conntrack_tuple
*orig
,
147 const struct nf_conntrack_l3proto
*l3proto
,
148 const struct nf_conntrack_l4proto
*l4proto
)
150 memset(inverse
, 0, sizeof(*inverse
));
152 inverse
->src
.l3num
= orig
->src
.l3num
;
153 if (l3proto
->invert_tuple(inverse
, orig
) == 0)
156 inverse
->dst
.dir
= !orig
->dst
.dir
;
158 inverse
->dst
.protonum
= orig
->dst
.protonum
;
159 return l4proto
->invert_tuple(inverse
, orig
);
161 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple
);
164 clean_from_lists(struct nf_conn
*ct
)
166 pr_debug("clean_from_lists(%p)\n", ct
);
167 hlist_nulls_del_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
);
168 hlist_nulls_del_rcu(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnnode
);
170 /* Destroy all pending expectations */
171 nf_ct_remove_expectations(ct
);
175 destroy_conntrack(struct nf_conntrack
*nfct
)
177 struct nf_conn
*ct
= (struct nf_conn
*)nfct
;
178 struct net
*net
= nf_ct_net(ct
);
179 struct nf_conntrack_l4proto
*l4proto
;
181 pr_debug("destroy_conntrack(%p)\n", ct
);
182 NF_CT_ASSERT(atomic_read(&nfct
->use
) == 0);
183 NF_CT_ASSERT(!timer_pending(&ct
->timeout
));
185 if (!test_bit(IPS_DYING_BIT
, &ct
->status
))
186 nf_conntrack_event(IPCT_DESTROY
, ct
);
187 set_bit(IPS_DYING_BIT
, &ct
->status
);
189 /* To make sure we don't get any weird locking issues here:
190 * destroy_conntrack() MUST NOT be called with a write lock
191 * to nf_conntrack_lock!!! -HW */
193 l4proto
= __nf_ct_l4proto_find(nf_ct_l3num(ct
), nf_ct_protonum(ct
));
194 if (l4proto
&& l4proto
->destroy
)
195 l4proto
->destroy(ct
);
199 spin_lock_bh(&nf_conntrack_lock
);
200 /* Expectations will have been removed in clean_from_lists,
201 * except TFTP can create an expectation on the first packet,
202 * before connection is in the list, so we need to clean here,
204 nf_ct_remove_expectations(ct
);
206 /* We overload first tuple to link into unconfirmed list. */
207 if (!nf_ct_is_confirmed(ct
)) {
208 BUG_ON(hlist_nulls_unhashed(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
));
209 hlist_nulls_del_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
);
212 NF_CT_STAT_INC(net
, delete);
213 spin_unlock_bh(&nf_conntrack_lock
);
216 nf_ct_put(ct
->master
);
218 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct
);
219 nf_conntrack_free(ct
);
222 static void death_by_timeout(unsigned long ul_conntrack
)
224 struct nf_conn
*ct
= (void *)ul_conntrack
;
225 struct net
*net
= nf_ct_net(ct
);
226 struct nf_conn_help
*help
= nfct_help(ct
);
227 struct nf_conntrack_helper
*helper
;
231 helper
= rcu_dereference(help
->helper
);
232 if (helper
&& helper
->destroy
)
237 spin_lock_bh(&nf_conntrack_lock
);
238 /* Inside lock so preempt is disabled on module removal path.
239 * Otherwise we can get spurious warnings. */
240 NF_CT_STAT_INC(net
, delete_list
);
241 clean_from_lists(ct
);
242 spin_unlock_bh(&nf_conntrack_lock
);
248 * - Caller must take a reference on returned object
249 * and recheck nf_ct_tuple_equal(tuple, &h->tuple)
251 * - Caller must lock nf_conntrack_lock before calling this function
253 struct nf_conntrack_tuple_hash
*
254 __nf_conntrack_find(struct net
*net
, const struct nf_conntrack_tuple
*tuple
)
256 struct nf_conntrack_tuple_hash
*h
;
257 struct hlist_nulls_node
*n
;
258 unsigned int hash
= hash_conntrack(tuple
);
260 /* Disable BHs the entire time since we normally need to disable them
261 * at least once for the stats anyway.
265 hlist_nulls_for_each_entry_rcu(h
, n
, &net
->ct
.hash
[hash
], hnnode
) {
266 if (nf_ct_tuple_equal(tuple
, &h
->tuple
)) {
267 NF_CT_STAT_INC(net
, found
);
271 NF_CT_STAT_INC(net
, searched
);
274 * if the nulls value we got at the end of this lookup is
275 * not the expected one, we must restart lookup.
276 * We probably met an item that was moved to another chain.
278 if (get_nulls_value(n
) != hash
)
284 EXPORT_SYMBOL_GPL(__nf_conntrack_find
);
286 /* Find a connection corresponding to a tuple. */
287 struct nf_conntrack_tuple_hash
*
288 nf_conntrack_find_get(struct net
*net
, const struct nf_conntrack_tuple
*tuple
)
290 struct nf_conntrack_tuple_hash
*h
;
295 h
= __nf_conntrack_find(net
, tuple
);
297 ct
= nf_ct_tuplehash_to_ctrack(h
);
298 if (unlikely(nf_ct_is_dying(ct
) ||
299 !atomic_inc_not_zero(&ct
->ct_general
.use
)))
302 if (unlikely(!nf_ct_tuple_equal(tuple
, &h
->tuple
))) {
312 EXPORT_SYMBOL_GPL(nf_conntrack_find_get
);
314 static void __nf_conntrack_hash_insert(struct nf_conn
*ct
,
316 unsigned int repl_hash
)
318 struct net
*net
= nf_ct_net(ct
);
320 hlist_nulls_add_head_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
,
321 &net
->ct
.hash
[hash
]);
322 hlist_nulls_add_head_rcu(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnnode
,
323 &net
->ct
.hash
[repl_hash
]);
326 void nf_conntrack_hash_insert(struct nf_conn
*ct
)
328 unsigned int hash
, repl_hash
;
330 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
331 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
333 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
335 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert
);
337 /* Confirm a connection given skb; places it in hash table */
339 __nf_conntrack_confirm(struct sk_buff
*skb
)
341 unsigned int hash
, repl_hash
;
342 struct nf_conntrack_tuple_hash
*h
;
344 struct nf_conn_help
*help
;
345 struct hlist_nulls_node
*n
;
346 enum ip_conntrack_info ctinfo
;
349 ct
= nf_ct_get(skb
, &ctinfo
);
352 /* ipt_REJECT uses nf_conntrack_attach to attach related
353 ICMP/TCP RST packets in other direction. Actual packet
354 which created connection will be IP_CT_NEW or for an
355 expected connection, IP_CT_RELATED. */
356 if (CTINFO2DIR(ctinfo
) != IP_CT_DIR_ORIGINAL
)
359 hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
360 repl_hash
= hash_conntrack(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
362 /* We're not in hash table, and we refuse to set up related
363 connections for unconfirmed conns. But packet copies and
364 REJECT will give spurious warnings here. */
365 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
367 /* No external references means noone else could have
369 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
370 pr_debug("Confirming conntrack %p\n", ct
);
372 spin_lock_bh(&nf_conntrack_lock
);
374 /* See if there's one in the list already, including reverse:
375 NAT could have grabbed it without realizing, since we're
376 not in the hash. If there is, we lost race. */
377 hlist_nulls_for_each_entry(h
, n
, &net
->ct
.hash
[hash
], hnnode
)
378 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
381 hlist_nulls_for_each_entry(h
, n
, &net
->ct
.hash
[repl_hash
], hnnode
)
382 if (nf_ct_tuple_equal(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
386 /* Remove from unconfirmed list */
387 hlist_nulls_del_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
);
389 /* Timer relative to confirmation time, not original
390 setting time, otherwise we'd get timer wrap in
391 weird delay cases. */
392 ct
->timeout
.expires
+= jiffies
;
393 add_timer(&ct
->timeout
);
394 atomic_inc(&ct
->ct_general
.use
);
395 set_bit(IPS_CONFIRMED_BIT
, &ct
->status
);
397 /* Since the lookup is lockless, hash insertion must be done after
398 * starting the timer and setting the CONFIRMED bit. The RCU barriers
399 * guarantee that no other CPU can find the conntrack before the above
400 * stores are visible.
402 __nf_conntrack_hash_insert(ct
, hash
, repl_hash
);
403 NF_CT_STAT_INC(net
, insert
);
404 spin_unlock_bh(&nf_conntrack_lock
);
406 help
= nfct_help(ct
);
407 if (help
&& help
->helper
)
408 nf_conntrack_event_cache(IPCT_HELPER
, ct
);
409 #ifdef CONFIG_NF_NAT_NEEDED
410 if (test_bit(IPS_SRC_NAT_DONE_BIT
, &ct
->status
) ||
411 test_bit(IPS_DST_NAT_DONE_BIT
, &ct
->status
))
412 nf_conntrack_event_cache(IPCT_NATINFO
, ct
);
414 nf_conntrack_event_cache(master_ct(ct
) ?
415 IPCT_RELATED
: IPCT_NEW
, ct
);
419 NF_CT_STAT_INC(net
, insert_failed
);
420 spin_unlock_bh(&nf_conntrack_lock
);
423 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm
);
425 /* Returns true if a connection correspondings to the tuple (required
428 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple
*tuple
,
429 const struct nf_conn
*ignored_conntrack
)
431 struct net
*net
= nf_ct_net(ignored_conntrack
);
432 struct nf_conntrack_tuple_hash
*h
;
433 struct hlist_nulls_node
*n
;
434 unsigned int hash
= hash_conntrack(tuple
);
436 /* Disable BHs the entire time since we need to disable them at
437 * least once for the stats anyway.
440 hlist_nulls_for_each_entry_rcu(h
, n
, &net
->ct
.hash
[hash
], hnnode
) {
441 if (nf_ct_tuplehash_to_ctrack(h
) != ignored_conntrack
&&
442 nf_ct_tuple_equal(tuple
, &h
->tuple
)) {
443 NF_CT_STAT_INC(net
, found
);
444 rcu_read_unlock_bh();
447 NF_CT_STAT_INC(net
, searched
);
449 rcu_read_unlock_bh();
453 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken
);
455 #define NF_CT_EVICTION_RANGE 8
457 /* There's a small race here where we may free a just-assured
458 connection. Too bad: we're in trouble anyway. */
459 static noinline
int early_drop(struct net
*net
, unsigned int hash
)
461 /* Use oldest entry, which is roughly LRU */
462 struct nf_conntrack_tuple_hash
*h
;
463 struct nf_conn
*ct
= NULL
, *tmp
;
464 struct hlist_nulls_node
*n
;
465 unsigned int i
, cnt
= 0;
469 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
470 hlist_nulls_for_each_entry_rcu(h
, n
, &net
->ct
.hash
[hash
],
472 tmp
= nf_ct_tuplehash_to_ctrack(h
);
473 if (!test_bit(IPS_ASSURED_BIT
, &tmp
->status
))
478 if (ct
&& unlikely(nf_ct_is_dying(ct
) ||
479 !atomic_inc_not_zero(&ct
->ct_general
.use
)))
481 if (ct
|| cnt
>= NF_CT_EVICTION_RANGE
)
483 hash
= (hash
+ 1) % nf_conntrack_htable_size
;
490 if (del_timer(&ct
->timeout
)) {
491 death_by_timeout((unsigned long)ct
);
493 NF_CT_STAT_INC_ATOMIC(net
, early_drop
);
499 struct nf_conn
*nf_conntrack_alloc(struct net
*net
,
500 const struct nf_conntrack_tuple
*orig
,
501 const struct nf_conntrack_tuple
*repl
,
506 if (unlikely(!nf_conntrack_hash_rnd_initted
)) {
507 get_random_bytes(&nf_conntrack_hash_rnd
,
508 sizeof(nf_conntrack_hash_rnd
));
509 nf_conntrack_hash_rnd_initted
= 1;
512 /* We don't want any race condition at early drop stage */
513 atomic_inc(&net
->ct
.count
);
515 if (nf_conntrack_max
&&
516 unlikely(atomic_read(&net
->ct
.count
) > nf_conntrack_max
)) {
517 unsigned int hash
= hash_conntrack(orig
);
518 if (!early_drop(net
, hash
)) {
519 atomic_dec(&net
->ct
.count
);
522 "nf_conntrack: table full, dropping"
524 return ERR_PTR(-ENOMEM
);
528 ct
= kmem_cache_zalloc(nf_conntrack_cachep
, gfp
);
530 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
531 atomic_dec(&net
->ct
.count
);
532 return ERR_PTR(-ENOMEM
);
535 atomic_set(&ct
->ct_general
.use
, 1);
536 ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
= *orig
;
537 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *repl
;
538 /* Don't set timer yet: wait for confirmation */
539 setup_timer(&ct
->timeout
, death_by_timeout
, (unsigned long)ct
);
546 EXPORT_SYMBOL_GPL(nf_conntrack_alloc
);
548 void nf_conntrack_free(struct nf_conn
*ct
)
550 struct net
*net
= nf_ct_net(ct
);
552 nf_ct_ext_destroy(ct
);
553 atomic_dec(&net
->ct
.count
);
555 kmem_cache_free(nf_conntrack_cachep
, ct
);
557 EXPORT_SYMBOL_GPL(nf_conntrack_free
);
559 /* Allocate a new conntrack: we return -ENOMEM if classification
560 failed due to stress. Otherwise it really is unclassifiable. */
561 static struct nf_conntrack_tuple_hash
*
562 init_conntrack(struct net
*net
,
563 const struct nf_conntrack_tuple
*tuple
,
564 struct nf_conntrack_l3proto
*l3proto
,
565 struct nf_conntrack_l4proto
*l4proto
,
567 unsigned int dataoff
)
570 struct nf_conn_help
*help
;
571 struct nf_conntrack_tuple repl_tuple
;
572 struct nf_conntrack_expect
*exp
;
574 if (!nf_ct_invert_tuple(&repl_tuple
, tuple
, l3proto
, l4proto
)) {
575 pr_debug("Can't invert tuple.\n");
579 ct
= nf_conntrack_alloc(net
, tuple
, &repl_tuple
, GFP_ATOMIC
);
581 pr_debug("Can't allocate conntrack.\n");
582 return (struct nf_conntrack_tuple_hash
*)ct
;
585 if (!l4proto
->new(ct
, skb
, dataoff
)) {
586 nf_conntrack_free(ct
);
587 pr_debug("init conntrack: can't track with proto module\n");
591 nf_ct_acct_ext_add(ct
, GFP_ATOMIC
);
593 spin_lock_bh(&nf_conntrack_lock
);
594 exp
= nf_ct_find_expectation(net
, tuple
);
596 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
598 /* Welcome, Mr. Bond. We've been expecting you... */
599 __set_bit(IPS_EXPECTED_BIT
, &ct
->status
);
600 ct
->master
= exp
->master
;
602 help
= nf_ct_helper_ext_add(ct
, GFP_ATOMIC
);
604 rcu_assign_pointer(help
->helper
, exp
->helper
);
607 #ifdef CONFIG_NF_CONNTRACK_MARK
608 ct
->mark
= exp
->master
->mark
;
610 #ifdef CONFIG_NF_CONNTRACK_SECMARK
611 ct
->secmark
= exp
->master
->secmark
;
613 nf_conntrack_get(&ct
->master
->ct_general
);
614 NF_CT_STAT_INC(net
, expect_new
);
616 __nf_ct_try_assign_helper(ct
, GFP_ATOMIC
);
617 NF_CT_STAT_INC(net
, new);
620 /* Overload tuple linked list to put us in unconfirmed list. */
621 hlist_nulls_add_head_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
,
622 &net
->ct
.unconfirmed
);
624 spin_unlock_bh(&nf_conntrack_lock
);
628 exp
->expectfn(ct
, exp
);
629 nf_ct_expect_put(exp
);
632 return &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
];
635 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
636 static inline struct nf_conn
*
637 resolve_normal_ct(struct net
*net
,
639 unsigned int dataoff
,
642 struct nf_conntrack_l3proto
*l3proto
,
643 struct nf_conntrack_l4proto
*l4proto
,
645 enum ip_conntrack_info
*ctinfo
)
647 struct nf_conntrack_tuple tuple
;
648 struct nf_conntrack_tuple_hash
*h
;
651 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
),
652 dataoff
, l3num
, protonum
, &tuple
, l3proto
,
654 pr_debug("resolve_normal_ct: Can't get tuple\n");
658 /* look for tuple match */
659 h
= nf_conntrack_find_get(net
, &tuple
);
661 h
= init_conntrack(net
, &tuple
, l3proto
, l4proto
, skb
, dataoff
);
667 ct
= nf_ct_tuplehash_to_ctrack(h
);
669 /* It exists; we have (non-exclusive) reference. */
670 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
) {
671 *ctinfo
= IP_CT_ESTABLISHED
+ IP_CT_IS_REPLY
;
672 /* Please set reply bit if this packet OK */
675 /* Once we've had two way comms, always ESTABLISHED. */
676 if (test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
677 pr_debug("nf_conntrack_in: normal packet for %p\n", ct
);
678 *ctinfo
= IP_CT_ESTABLISHED
;
679 } else if (test_bit(IPS_EXPECTED_BIT
, &ct
->status
)) {
680 pr_debug("nf_conntrack_in: related packet for %p\n",
682 *ctinfo
= IP_CT_RELATED
;
684 pr_debug("nf_conntrack_in: new packet for %p\n", ct
);
689 skb
->nfct
= &ct
->ct_general
;
690 skb
->nfctinfo
= *ctinfo
;
695 nf_conntrack_in(struct net
*net
, u_int8_t pf
, unsigned int hooknum
,
699 enum ip_conntrack_info ctinfo
;
700 struct nf_conntrack_l3proto
*l3proto
;
701 struct nf_conntrack_l4proto
*l4proto
;
702 unsigned int dataoff
;
707 /* Previously seen (loopback or untracked)? Ignore. */
709 NF_CT_STAT_INC_ATOMIC(net
, ignore
);
713 /* rcu_read_lock()ed by nf_hook_slow */
714 l3proto
= __nf_ct_l3proto_find(pf
);
715 ret
= l3proto
->get_l4proto(skb
, skb_network_offset(skb
),
716 &dataoff
, &protonum
);
718 pr_debug("not prepared to track yet or error occured\n");
719 NF_CT_STAT_INC_ATOMIC(net
, error
);
720 NF_CT_STAT_INC_ATOMIC(net
, invalid
);
724 l4proto
= __nf_ct_l4proto_find(pf
, protonum
);
726 /* It may be an special packet, error, unclean...
727 * inverse of the return code tells to the netfilter
728 * core what to do with the packet. */
729 if (l4proto
->error
!= NULL
) {
730 ret
= l4proto
->error(net
, skb
, dataoff
, &ctinfo
, pf
, hooknum
);
732 NF_CT_STAT_INC_ATOMIC(net
, error
);
733 NF_CT_STAT_INC_ATOMIC(net
, invalid
);
738 ct
= resolve_normal_ct(net
, skb
, dataoff
, pf
, protonum
,
739 l3proto
, l4proto
, &set_reply
, &ctinfo
);
741 /* Not valid part of a connection */
742 NF_CT_STAT_INC_ATOMIC(net
, invalid
);
747 /* Too stressed to deal. */
748 NF_CT_STAT_INC_ATOMIC(net
, drop
);
752 NF_CT_ASSERT(skb
->nfct
);
754 ret
= l4proto
->packet(ct
, skb
, dataoff
, ctinfo
, pf
, hooknum
);
756 /* Invalid: inverse of the return code tells
757 * the netfilter core what to do */
758 pr_debug("nf_conntrack_in: Can't track with proto module\n");
759 nf_conntrack_put(skb
->nfct
);
761 NF_CT_STAT_INC_ATOMIC(net
, invalid
);
763 NF_CT_STAT_INC_ATOMIC(net
, drop
);
767 if (set_reply
&& !test_and_set_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
))
768 nf_conntrack_event_cache(IPCT_STATUS
, ct
);
772 EXPORT_SYMBOL_GPL(nf_conntrack_in
);
774 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple
*inverse
,
775 const struct nf_conntrack_tuple
*orig
)
780 ret
= nf_ct_invert_tuple(inverse
, orig
,
781 __nf_ct_l3proto_find(orig
->src
.l3num
),
782 __nf_ct_l4proto_find(orig
->src
.l3num
,
783 orig
->dst
.protonum
));
787 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr
);
789 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
790 implicitly racy: see __nf_conntrack_confirm */
791 void nf_conntrack_alter_reply(struct nf_conn
*ct
,
792 const struct nf_conntrack_tuple
*newreply
)
794 struct nf_conn_help
*help
= nfct_help(ct
);
796 /* Should be unconfirmed, so not in hash table yet */
797 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
799 pr_debug("Altering reply tuple of %p to ", ct
);
800 nf_ct_dump_tuple(newreply
);
802 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *newreply
;
803 if (ct
->master
|| (help
&& !hlist_empty(&help
->expectations
)))
807 __nf_ct_try_assign_helper(ct
, GFP_ATOMIC
);
810 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply
);
812 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
813 void __nf_ct_refresh_acct(struct nf_conn
*ct
,
814 enum ip_conntrack_info ctinfo
,
815 const struct sk_buff
*skb
,
816 unsigned long extra_jiffies
,
821 NF_CT_ASSERT(ct
->timeout
.data
== (unsigned long)ct
);
824 spin_lock_bh(&nf_conntrack_lock
);
826 /* Only update if this is not a fixed timeout */
827 if (test_bit(IPS_FIXED_TIMEOUT_BIT
, &ct
->status
))
830 /* If not in hash table, timer will not be active yet */
831 if (!nf_ct_is_confirmed(ct
)) {
832 ct
->timeout
.expires
= extra_jiffies
;
833 event
= IPCT_REFRESH
;
835 unsigned long newtime
= jiffies
+ extra_jiffies
;
837 /* Only update the timeout if the new timeout is at least
838 HZ jiffies from the old timeout. Need del_timer for race
839 avoidance (may already be dying). */
840 if (newtime
- ct
->timeout
.expires
>= HZ
841 && del_timer(&ct
->timeout
)) {
842 ct
->timeout
.expires
= newtime
;
843 add_timer(&ct
->timeout
);
844 event
= IPCT_REFRESH
;
850 struct nf_conn_counter
*acct
;
852 acct
= nf_conn_acct_find(ct
);
854 acct
[CTINFO2DIR(ctinfo
)].packets
++;
855 acct
[CTINFO2DIR(ctinfo
)].bytes
+=
856 skb
->len
- skb_network_offset(skb
);
860 spin_unlock_bh(&nf_conntrack_lock
);
862 /* must be unlocked when calling event cache */
864 nf_conntrack_event_cache(event
, ct
);
866 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct
);
868 bool __nf_ct_kill_acct(struct nf_conn
*ct
,
869 enum ip_conntrack_info ctinfo
,
870 const struct sk_buff
*skb
,
874 struct nf_conn_counter
*acct
;
876 spin_lock_bh(&nf_conntrack_lock
);
877 acct
= nf_conn_acct_find(ct
);
879 acct
[CTINFO2DIR(ctinfo
)].packets
++;
880 acct
[CTINFO2DIR(ctinfo
)].bytes
+=
881 skb
->len
- skb_network_offset(skb
);
883 spin_unlock_bh(&nf_conntrack_lock
);
886 if (del_timer(&ct
->timeout
)) {
887 ct
->timeout
.function((unsigned long)ct
);
892 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct
);
894 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
896 #include <linux/netfilter/nfnetlink.h>
897 #include <linux/netfilter/nfnetlink_conntrack.h>
898 #include <linux/mutex.h>
900 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
901 * in ip_conntrack_core, since we don't want the protocols to autoload
902 * or depend on ctnetlink */
903 int nf_ct_port_tuple_to_nlattr(struct sk_buff
*skb
,
904 const struct nf_conntrack_tuple
*tuple
)
906 NLA_PUT_BE16(skb
, CTA_PROTO_SRC_PORT
, tuple
->src
.u
.tcp
.port
);
907 NLA_PUT_BE16(skb
, CTA_PROTO_DST_PORT
, tuple
->dst
.u
.tcp
.port
);
913 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr
);
915 const struct nla_policy nf_ct_port_nla_policy
[CTA_PROTO_MAX
+1] = {
916 [CTA_PROTO_SRC_PORT
] = { .type
= NLA_U16
},
917 [CTA_PROTO_DST_PORT
] = { .type
= NLA_U16
},
919 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy
);
921 int nf_ct_port_nlattr_to_tuple(struct nlattr
*tb
[],
922 struct nf_conntrack_tuple
*t
)
924 if (!tb
[CTA_PROTO_SRC_PORT
] || !tb
[CTA_PROTO_DST_PORT
])
927 t
->src
.u
.tcp
.port
= nla_get_be16(tb
[CTA_PROTO_SRC_PORT
]);
928 t
->dst
.u
.tcp
.port
= nla_get_be16(tb
[CTA_PROTO_DST_PORT
]);
932 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple
);
934 int nf_ct_port_nlattr_tuple_size(void)
936 return nla_policy_len(nf_ct_port_nla_policy
, CTA_PROTO_MAX
+ 1);
938 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size
);
941 /* Used by ipt_REJECT and ip6t_REJECT. */
942 static void nf_conntrack_attach(struct sk_buff
*nskb
, struct sk_buff
*skb
)
945 enum ip_conntrack_info ctinfo
;
947 /* This ICMP is in reverse direction to the packet which caused it */
948 ct
= nf_ct_get(skb
, &ctinfo
);
949 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
)
950 ctinfo
= IP_CT_RELATED
+ IP_CT_IS_REPLY
;
952 ctinfo
= IP_CT_RELATED
;
954 /* Attach to new skbuff, and increment count */
955 nskb
->nfct
= &ct
->ct_general
;
956 nskb
->nfctinfo
= ctinfo
;
957 nf_conntrack_get(nskb
->nfct
);
960 /* Bring out ya dead! */
961 static struct nf_conn
*
962 get_next_corpse(struct net
*net
, int (*iter
)(struct nf_conn
*i
, void *data
),
963 void *data
, unsigned int *bucket
)
965 struct nf_conntrack_tuple_hash
*h
;
967 struct hlist_nulls_node
*n
;
969 spin_lock_bh(&nf_conntrack_lock
);
970 for (; *bucket
< nf_conntrack_htable_size
; (*bucket
)++) {
971 hlist_nulls_for_each_entry(h
, n
, &net
->ct
.hash
[*bucket
], hnnode
) {
972 ct
= nf_ct_tuplehash_to_ctrack(h
);
977 hlist_nulls_for_each_entry(h
, n
, &net
->ct
.unconfirmed
, hnnode
) {
978 ct
= nf_ct_tuplehash_to_ctrack(h
);
980 set_bit(IPS_DYING_BIT
, &ct
->status
);
982 spin_unlock_bh(&nf_conntrack_lock
);
985 atomic_inc(&ct
->ct_general
.use
);
986 spin_unlock_bh(&nf_conntrack_lock
);
990 void nf_ct_iterate_cleanup(struct net
*net
,
991 int (*iter
)(struct nf_conn
*i
, void *data
),
995 unsigned int bucket
= 0;
997 while ((ct
= get_next_corpse(net
, iter
, data
, &bucket
)) != NULL
) {
998 /* Time to push up daises... */
999 if (del_timer(&ct
->timeout
))
1000 death_by_timeout((unsigned long)ct
);
1001 /* ... else the timer will get him soon. */
1006 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup
);
1008 struct __nf_ct_flush_report
{
1013 static int kill_all(struct nf_conn
*i
, void *data
)
1015 struct __nf_ct_flush_report
*fr
= (struct __nf_ct_flush_report
*)data
;
1017 /* get_next_corpse sets the dying bit for us */
1018 nf_conntrack_event_report(IPCT_DESTROY
,
1025 void nf_ct_free_hashtable(void *hash
, int vmalloced
, unsigned int size
)
1030 free_pages((unsigned long)hash
,
1031 get_order(sizeof(struct hlist_head
) * size
));
1033 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable
);
1035 void nf_conntrack_flush(struct net
*net
, u32 pid
, int report
)
1037 struct __nf_ct_flush_report fr
= {
1041 nf_ct_iterate_cleanup(net
, kill_all
, &fr
);
1043 EXPORT_SYMBOL_GPL(nf_conntrack_flush
);
1045 static void nf_conntrack_cleanup_init_net(void)
1047 nf_conntrack_helper_fini();
1048 nf_conntrack_proto_fini();
1049 kmem_cache_destroy(nf_conntrack_cachep
);
1052 static void nf_conntrack_cleanup_net(struct net
*net
)
1054 nf_ct_event_cache_flush(net
);
1055 nf_conntrack_ecache_fini(net
);
1057 nf_conntrack_flush(net
, 0, 0);
1058 if (atomic_read(&net
->ct
.count
) != 0) {
1060 goto i_see_dead_people
;
1062 /* wait until all references to nf_conntrack_untracked are dropped */
1063 while (atomic_read(&nf_conntrack_untracked
.ct_general
.use
) > 1)
1066 nf_ct_free_hashtable(net
->ct
.hash
, net
->ct
.hash_vmalloc
,
1067 nf_conntrack_htable_size
);
1068 nf_conntrack_acct_fini(net
);
1069 nf_conntrack_expect_fini(net
);
1070 free_percpu(net
->ct
.stat
);
1073 /* Mishearing the voices in his head, our hero wonders how he's
1074 supposed to kill the mall. */
1075 void nf_conntrack_cleanup(struct net
*net
)
1077 if (net_eq(net
, &init_net
))
1078 rcu_assign_pointer(ip_ct_attach
, NULL
);
1080 /* This makes sure all current packets have passed through
1081 netfilter framework. Roll on, two-stage module
1085 nf_conntrack_cleanup_net(net
);
1087 if (net_eq(net
, &init_net
)) {
1088 rcu_assign_pointer(nf_ct_destroy
, NULL
);
1089 nf_conntrack_cleanup_init_net();
1093 void *nf_ct_alloc_hashtable(unsigned int *sizep
, int *vmalloced
, int nulls
)
1095 struct hlist_nulls_head
*hash
;
1096 unsigned int nr_slots
, i
;
1101 BUILD_BUG_ON(sizeof(struct hlist_nulls_head
) != sizeof(struct hlist_head
));
1102 nr_slots
= *sizep
= roundup(*sizep
, PAGE_SIZE
/ sizeof(struct hlist_nulls_head
));
1103 sz
= nr_slots
* sizeof(struct hlist_nulls_head
);
1104 hash
= (void *)__get_free_pages(GFP_KERNEL
| __GFP_NOWARN
| __GFP_ZERO
,
1108 printk(KERN_WARNING
"nf_conntrack: falling back to vmalloc.\n");
1109 hash
= __vmalloc(sz
, GFP_KERNEL
| __GFP_ZERO
, PAGE_KERNEL
);
1113 for (i
= 0; i
< nr_slots
; i
++)
1114 INIT_HLIST_NULLS_HEAD(&hash
[i
], i
);
1118 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable
);
1120 int nf_conntrack_set_hashsize(const char *val
, struct kernel_param
*kp
)
1122 int i
, bucket
, vmalloced
, old_vmalloced
;
1123 unsigned int hashsize
, old_size
;
1125 struct hlist_nulls_head
*hash
, *old_hash
;
1126 struct nf_conntrack_tuple_hash
*h
;
1128 /* On boot, we can set this without any fancy locking. */
1129 if (!nf_conntrack_htable_size
)
1130 return param_set_uint(val
, kp
);
1132 hashsize
= simple_strtoul(val
, NULL
, 0);
1136 hash
= nf_ct_alloc_hashtable(&hashsize
, &vmalloced
, 1);
1140 /* We have to rehahs for the new table anyway, so we also can
1141 * use a newrandom seed */
1142 get_random_bytes(&rnd
, sizeof(rnd
));
1144 /* Lookups in the old hash might happen in parallel, which means we
1145 * might get false negatives during connection lookup. New connections
1146 * created because of a false negative won't make it into the hash
1147 * though since that required taking the lock.
1149 spin_lock_bh(&nf_conntrack_lock
);
1150 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
1151 while (!hlist_nulls_empty(&init_net
.ct
.hash
[i
])) {
1152 h
= hlist_nulls_entry(init_net
.ct
.hash
[i
].first
,
1153 struct nf_conntrack_tuple_hash
, hnnode
);
1154 hlist_nulls_del_rcu(&h
->hnnode
);
1155 bucket
= __hash_conntrack(&h
->tuple
, hashsize
, rnd
);
1156 hlist_nulls_add_head_rcu(&h
->hnnode
, &hash
[bucket
]);
1159 old_size
= nf_conntrack_htable_size
;
1160 old_vmalloced
= init_net
.ct
.hash_vmalloc
;
1161 old_hash
= init_net
.ct
.hash
;
1163 nf_conntrack_htable_size
= hashsize
;
1164 init_net
.ct
.hash_vmalloc
= vmalloced
;
1165 init_net
.ct
.hash
= hash
;
1166 nf_conntrack_hash_rnd
= rnd
;
1167 spin_unlock_bh(&nf_conntrack_lock
);
1169 nf_ct_free_hashtable(old_hash
, old_vmalloced
, old_size
);
1172 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize
);
1174 module_param_call(hashsize
, nf_conntrack_set_hashsize
, param_get_uint
,
1175 &nf_conntrack_htable_size
, 0600);
1177 static int nf_conntrack_init_init_net(void)
1182 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1183 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1184 if (!nf_conntrack_htable_size
) {
1185 nf_conntrack_htable_size
1186 = (((num_physpages
<< PAGE_SHIFT
) / 16384)
1187 / sizeof(struct hlist_head
));
1188 if (num_physpages
> (1024 * 1024 * 1024 / PAGE_SIZE
))
1189 nf_conntrack_htable_size
= 16384;
1190 if (nf_conntrack_htable_size
< 32)
1191 nf_conntrack_htable_size
= 32;
1193 /* Use a max. factor of four by default to get the same max as
1194 * with the old struct list_heads. When a table size is given
1195 * we use the old value of 8 to avoid reducing the max.
1199 nf_conntrack_max
= max_factor
* nf_conntrack_htable_size
;
1201 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1202 NF_CONNTRACK_VERSION
, nf_conntrack_htable_size
,
1205 nf_conntrack_cachep
= kmem_cache_create("nf_conntrack",
1206 sizeof(struct nf_conn
),
1207 0, SLAB_DESTROY_BY_RCU
, NULL
);
1208 if (!nf_conntrack_cachep
) {
1209 printk(KERN_ERR
"Unable to create nf_conn slab cache\n");
1214 ret
= nf_conntrack_proto_init();
1218 ret
= nf_conntrack_helper_init();
1225 nf_conntrack_proto_fini();
1227 kmem_cache_destroy(nf_conntrack_cachep
);
1232 static int nf_conntrack_init_net(struct net
*net
)
1236 atomic_set(&net
->ct
.count
, 0);
1237 INIT_HLIST_NULLS_HEAD(&net
->ct
.unconfirmed
, 0);
1238 net
->ct
.stat
= alloc_percpu(struct ip_conntrack_stat
);
1239 if (!net
->ct
.stat
) {
1243 ret
= nf_conntrack_ecache_init(net
);
1246 net
->ct
.hash
= nf_ct_alloc_hashtable(&nf_conntrack_htable_size
,
1247 &net
->ct
.hash_vmalloc
, 1);
1248 if (!net
->ct
.hash
) {
1250 printk(KERN_ERR
"Unable to create nf_conntrack_hash\n");
1253 ret
= nf_conntrack_expect_init(net
);
1256 ret
= nf_conntrack_acct_init(net
);
1260 /* Set up fake conntrack:
1261 - to never be deleted, not in any hashes */
1262 #ifdef CONFIG_NET_NS
1263 nf_conntrack_untracked
.ct_net
= &init_net
;
1265 atomic_set(&nf_conntrack_untracked
.ct_general
.use
, 1);
1266 /* - and look it like as a confirmed connection */
1267 set_bit(IPS_CONFIRMED_BIT
, &nf_conntrack_untracked
.status
);
1272 nf_conntrack_expect_fini(net
);
1274 nf_ct_free_hashtable(net
->ct
.hash
, net
->ct
.hash_vmalloc
,
1275 nf_conntrack_htable_size
);
1277 nf_conntrack_ecache_fini(net
);
1279 free_percpu(net
->ct
.stat
);
1284 int nf_conntrack_init(struct net
*net
)
1288 if (net_eq(net
, &init_net
)) {
1289 ret
= nf_conntrack_init_init_net();
1293 ret
= nf_conntrack_init_net(net
);
1297 if (net_eq(net
, &init_net
)) {
1298 /* For use by REJECT target */
1299 rcu_assign_pointer(ip_ct_attach
, nf_conntrack_attach
);
1300 rcu_assign_pointer(nf_ct_destroy
, destroy_conntrack
);
1305 if (net_eq(net
, &init_net
))
1306 nf_conntrack_cleanup_init_net();