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.
13 * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
14 * - new API and handling of conntrack/nat helpers
15 * - now capable of multiple expectations for one master
16 * 16 Jul 2002: Harald Welte <laforge@gnumonks.org>
17 * - add usage/reference counts to ip_conntrack_expect
18 * - export ip_conntrack[_expect]_{find_get,put} functions
19 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
20 * - generalize L3 protocol denendent part.
21 * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
22 * - add support various size of conntrack structures.
23 * 26 Jan 2006: Harald Welte <laforge@netfilter.org>
24 * - restructure nf_conn (introduce nf_conn_help)
25 * - redesign 'features' how they were originally intended
26 * 26 Feb 2006: Pablo Neira Ayuso <pablo@eurodev.net>
27 * - add support for L3 protocol module load on demand.
29 * Derived from net/ipv4/netfilter/ip_conntrack_core.c
32 #include <linux/types.h>
33 #include <linux/netfilter.h>
34 #include <linux/module.h>
35 #include <linux/skbuff.h>
36 #include <linux/proc_fs.h>
37 #include <linux/vmalloc.h>
38 #include <linux/stddef.h>
39 #include <linux/slab.h>
40 #include <linux/random.h>
41 #include <linux/jhash.h>
42 #include <linux/err.h>
43 #include <linux/percpu.h>
44 #include <linux/moduleparam.h>
45 #include <linux/notifier.h>
46 #include <linux/kernel.h>
47 #include <linux/netdevice.h>
48 #include <linux/socket.h>
51 #include <net/netfilter/nf_conntrack.h>
52 #include <net/netfilter/nf_conntrack_l3proto.h>
53 #include <net/netfilter/nf_conntrack_l4proto.h>
54 #include <net/netfilter/nf_conntrack_expect.h>
55 #include <net/netfilter/nf_conntrack_helper.h>
56 #include <net/netfilter/nf_conntrack_core.h>
58 #define NF_CONNTRACK_VERSION "0.5.0"
63 #define DEBUGP(format, args...)
66 DEFINE_RWLOCK(nf_conntrack_lock);
67 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
69 /* nf_conntrack_standalone needs this */
70 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
71 EXPORT_SYMBOL_GPL(nf_conntrack_count);
73 void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
74 EXPORT_SYMBOL_GPL(nf_conntrack_destroyed);
76 unsigned int nf_conntrack_htable_size __read_mostly;
77 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
79 int nf_conntrack_max __read_mostly;
80 EXPORT_SYMBOL_GPL(nf_conntrack_max);
82 struct list_head *nf_conntrack_hash __read_mostly;
83 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
85 struct nf_conn nf_conntrack_untracked __read_mostly;
86 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
88 unsigned int nf_ct_log_invalid __read_mostly;
89 LIST_HEAD(unconfirmed);
90 static int nf_conntrack_vmalloc __read_mostly;
92 static unsigned int nf_conntrack_next_id;
94 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
95 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
98 * This scheme offers various size of "struct nf_conn" dependent on
99 * features(helper, nat, ...)
102 #define NF_CT_FEATURES_NAMELEN 256
104 /* name of slab cache. printed in /proc/slabinfo */
107 /* size of slab cache */
110 /* slab cache pointer */
111 kmem_cache_t *cachep;
113 /* allocated slab cache + modules which uses this slab cache */
116 } nf_ct_cache[NF_CT_F_NUM];
118 /* protect members of nf_ct_cache except of "use" */
119 DEFINE_RWLOCK(nf_ct_cache_lock);
121 /* This avoids calling kmem_cache_create() with same name simultaneously */
122 static DEFINE_MUTEX(nf_ct_cache_mutex);
124 static int nf_conntrack_hash_rnd_initted;
125 static unsigned int nf_conntrack_hash_rnd;
127 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
128 unsigned int size, unsigned int rnd)
131 a = jhash((void *)tuple->src.u3.all, sizeof(tuple->src.u3.all),
132 ((tuple->src.l3num) << 16) | tuple->dst.protonum);
133 b = jhash((void *)tuple->dst.u3.all, sizeof(tuple->dst.u3.all),
134 (tuple->src.u.all << 16) | tuple->dst.u.all);
136 return jhash_2words(a, b, rnd) % size;
139 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
141 return __hash_conntrack(tuple, nf_conntrack_htable_size,
142 nf_conntrack_hash_rnd);
145 int nf_conntrack_register_cache(u_int32_t features, const char *name,
150 kmem_cache_t *cachep;
152 DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
153 features, name, size);
155 if (features < NF_CT_F_BASIC || features >= NF_CT_F_NUM) {
156 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
161 mutex_lock(&nf_ct_cache_mutex);
163 write_lock_bh(&nf_ct_cache_lock);
164 /* e.g: multiple helpers are loaded */
165 if (nf_ct_cache[features].use > 0) {
166 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
167 if ((!strncmp(nf_ct_cache[features].name, name,
168 NF_CT_FEATURES_NAMELEN))
169 && nf_ct_cache[features].size == size) {
170 DEBUGP("nf_conntrack_register_cache: reusing.\n");
171 nf_ct_cache[features].use++;
176 write_unlock_bh(&nf_ct_cache_lock);
177 mutex_unlock(&nf_ct_cache_mutex);
180 write_unlock_bh(&nf_ct_cache_lock);
183 * The memory space for name of slab cache must be alive until
184 * cache is destroyed.
186 cache_name = kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN, GFP_ATOMIC);
187 if (cache_name == NULL) {
188 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
193 if (strlcpy(cache_name, name, NF_CT_FEATURES_NAMELEN)
194 >= NF_CT_FEATURES_NAMELEN) {
195 printk("nf_conntrack_register_cache: name too long\n");
200 cachep = kmem_cache_create(cache_name, size, 0, 0,
203 printk("nf_conntrack_register_cache: Can't create slab cache "
204 "for the features = 0x%x\n", features);
209 write_lock_bh(&nf_ct_cache_lock);
210 nf_ct_cache[features].use = 1;
211 nf_ct_cache[features].size = size;
212 nf_ct_cache[features].cachep = cachep;
213 nf_ct_cache[features].name = cache_name;
214 write_unlock_bh(&nf_ct_cache_lock);
221 mutex_unlock(&nf_ct_cache_mutex);
224 EXPORT_SYMBOL_GPL(nf_conntrack_register_cache);
226 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
227 void nf_conntrack_unregister_cache(u_int32_t features)
229 kmem_cache_t *cachep;
233 * This assures that kmem_cache_create() isn't called before destroying
236 DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features);
237 mutex_lock(&nf_ct_cache_mutex);
239 write_lock_bh(&nf_ct_cache_lock);
240 if (--nf_ct_cache[features].use > 0) {
241 write_unlock_bh(&nf_ct_cache_lock);
242 mutex_unlock(&nf_ct_cache_mutex);
245 cachep = nf_ct_cache[features].cachep;
246 name = nf_ct_cache[features].name;
247 nf_ct_cache[features].cachep = NULL;
248 nf_ct_cache[features].name = NULL;
249 nf_ct_cache[features].size = 0;
250 write_unlock_bh(&nf_ct_cache_lock);
254 kmem_cache_destroy(cachep);
257 mutex_unlock(&nf_ct_cache_mutex);
259 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_cache);
262 nf_ct_get_tuple(const struct sk_buff *skb,
264 unsigned int dataoff,
267 struct nf_conntrack_tuple *tuple,
268 const struct nf_conntrack_l3proto *l3proto,
269 const struct nf_conntrack_l4proto *l4proto)
271 NF_CT_TUPLE_U_BLANK(tuple);
273 tuple->src.l3num = l3num;
274 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
277 tuple->dst.protonum = protonum;
278 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
280 return l4proto->pkt_to_tuple(skb, dataoff, tuple);
282 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
285 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
286 const struct nf_conntrack_tuple *orig,
287 const struct nf_conntrack_l3proto *l3proto,
288 const struct nf_conntrack_l4proto *l4proto)
290 NF_CT_TUPLE_U_BLANK(inverse);
292 inverse->src.l3num = orig->src.l3num;
293 if (l3proto->invert_tuple(inverse, orig) == 0)
296 inverse->dst.dir = !orig->dst.dir;
298 inverse->dst.protonum = orig->dst.protonum;
299 return l4proto->invert_tuple(inverse, orig);
301 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
304 clean_from_lists(struct nf_conn *ct)
306 DEBUGP("clean_from_lists(%p)\n", ct);
307 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
308 list_del(&ct->tuplehash[IP_CT_DIR_REPLY].list);
310 /* Destroy all pending expectations */
311 nf_ct_remove_expectations(ct);
315 destroy_conntrack(struct nf_conntrack *nfct)
317 struct nf_conn *ct = (struct nf_conn *)nfct;
318 struct nf_conn_help *help = nfct_help(ct);
319 struct nf_conntrack_l3proto *l3proto;
320 struct nf_conntrack_l4proto *l4proto;
322 DEBUGP("destroy_conntrack(%p)\n", ct);
323 NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
324 NF_CT_ASSERT(!timer_pending(&ct->timeout));
326 nf_conntrack_event(IPCT_DESTROY, ct);
327 set_bit(IPS_DYING_BIT, &ct->status);
329 if (help && help->helper && help->helper->destroy)
330 help->helper->destroy(ct);
332 /* To make sure we don't get any weird locking issues here:
333 * destroy_conntrack() MUST NOT be called with a write lock
334 * to nf_conntrack_lock!!! -HW */
335 l3proto = __nf_ct_l3proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num);
336 if (l3proto && l3proto->destroy)
337 l3proto->destroy(ct);
339 l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num, ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
340 if (l4proto && l4proto->destroy)
341 l4proto->destroy(ct);
343 if (nf_conntrack_destroyed)
344 nf_conntrack_destroyed(ct);
346 write_lock_bh(&nf_conntrack_lock);
347 /* Expectations will have been removed in clean_from_lists,
348 * except TFTP can create an expectation on the first packet,
349 * before connection is in the list, so we need to clean here,
351 nf_ct_remove_expectations(ct);
353 /* We overload first tuple to link into unconfirmed list. */
354 if (!nf_ct_is_confirmed(ct)) {
355 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
356 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
359 NF_CT_STAT_INC(delete);
360 write_unlock_bh(&nf_conntrack_lock);
363 nf_ct_put(ct->master);
365 DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
366 nf_conntrack_free(ct);
369 static void death_by_timeout(unsigned long ul_conntrack)
371 struct nf_conn *ct = (void *)ul_conntrack;
373 write_lock_bh(&nf_conntrack_lock);
374 /* Inside lock so preempt is disabled on module removal path.
375 * Otherwise we can get spurious warnings. */
376 NF_CT_STAT_INC(delete_list);
377 clean_from_lists(ct);
378 write_unlock_bh(&nf_conntrack_lock);
382 struct nf_conntrack_tuple_hash *
383 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
384 const struct nf_conn *ignored_conntrack)
386 struct nf_conntrack_tuple_hash *h;
387 unsigned int hash = hash_conntrack(tuple);
389 list_for_each_entry(h, &nf_conntrack_hash[hash], list) {
390 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
391 nf_ct_tuple_equal(tuple, &h->tuple)) {
392 NF_CT_STAT_INC(found);
395 NF_CT_STAT_INC(searched);
400 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
402 /* Find a connection corresponding to a tuple. */
403 struct nf_conntrack_tuple_hash *
404 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple,
405 const struct nf_conn *ignored_conntrack)
407 struct nf_conntrack_tuple_hash *h;
409 read_lock_bh(&nf_conntrack_lock);
410 h = __nf_conntrack_find(tuple, ignored_conntrack);
412 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
413 read_unlock_bh(&nf_conntrack_lock);
417 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
419 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
421 unsigned int repl_hash)
423 ct->id = ++nf_conntrack_next_id;
424 list_add(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list,
425 &nf_conntrack_hash[hash]);
426 list_add(&ct->tuplehash[IP_CT_DIR_REPLY].list,
427 &nf_conntrack_hash[repl_hash]);
430 void nf_conntrack_hash_insert(struct nf_conn *ct)
432 unsigned int hash, repl_hash;
434 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
435 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
437 write_lock_bh(&nf_conntrack_lock);
438 __nf_conntrack_hash_insert(ct, hash, repl_hash);
439 write_unlock_bh(&nf_conntrack_lock);
441 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
443 /* Confirm a connection given skb; places it in hash table */
445 __nf_conntrack_confirm(struct sk_buff **pskb)
447 unsigned int hash, repl_hash;
448 struct nf_conntrack_tuple_hash *h;
450 struct nf_conn_help *help;
451 enum ip_conntrack_info ctinfo;
453 ct = nf_ct_get(*pskb, &ctinfo);
455 /* ipt_REJECT uses nf_conntrack_attach to attach related
456 ICMP/TCP RST packets in other direction. Actual packet
457 which created connection will be IP_CT_NEW or for an
458 expected connection, IP_CT_RELATED. */
459 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
462 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
463 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
465 /* We're not in hash table, and we refuse to set up related
466 connections for unconfirmed conns. But packet copies and
467 REJECT will give spurious warnings here. */
468 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
470 /* No external references means noone else could have
472 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
473 DEBUGP("Confirming conntrack %p\n", ct);
475 write_lock_bh(&nf_conntrack_lock);
477 /* See if there's one in the list already, including reverse:
478 NAT could have grabbed it without realizing, since we're
479 not in the hash. If there is, we lost race. */
480 list_for_each_entry(h, &nf_conntrack_hash[hash], list)
481 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
484 list_for_each_entry(h, &nf_conntrack_hash[repl_hash], list)
485 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
489 /* Remove from unconfirmed list */
490 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
492 __nf_conntrack_hash_insert(ct, hash, repl_hash);
493 /* Timer relative to confirmation time, not original
494 setting time, otherwise we'd get timer wrap in
495 weird delay cases. */
496 ct->timeout.expires += jiffies;
497 add_timer(&ct->timeout);
498 atomic_inc(&ct->ct_general.use);
499 set_bit(IPS_CONFIRMED_BIT, &ct->status);
500 NF_CT_STAT_INC(insert);
501 write_unlock_bh(&nf_conntrack_lock);
502 help = nfct_help(ct);
503 if (help && help->helper)
504 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
505 #ifdef CONFIG_NF_NAT_NEEDED
506 if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
507 test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
508 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
510 nf_conntrack_event_cache(master_ct(ct) ?
511 IPCT_RELATED : IPCT_NEW, *pskb);
515 NF_CT_STAT_INC(insert_failed);
516 write_unlock_bh(&nf_conntrack_lock);
519 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
521 /* Returns true if a connection correspondings to the tuple (required
524 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
525 const struct nf_conn *ignored_conntrack)
527 struct nf_conntrack_tuple_hash *h;
529 read_lock_bh(&nf_conntrack_lock);
530 h = __nf_conntrack_find(tuple, ignored_conntrack);
531 read_unlock_bh(&nf_conntrack_lock);
535 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
537 /* There's a small race here where we may free a just-assured
538 connection. Too bad: we're in trouble anyway. */
539 static int early_drop(struct list_head *chain)
541 /* Traverse backwards: gives us oldest, which is roughly LRU */
542 struct nf_conntrack_tuple_hash *h;
543 struct nf_conn *ct = NULL, *tmp;
546 read_lock_bh(&nf_conntrack_lock);
547 list_for_each_entry_reverse(h, chain, list) {
548 tmp = nf_ct_tuplehash_to_ctrack(h);
549 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) {
551 atomic_inc(&ct->ct_general.use);
555 read_unlock_bh(&nf_conntrack_lock);
560 if (del_timer(&ct->timeout)) {
561 death_by_timeout((unsigned long)ct);
563 NF_CT_STAT_INC(early_drop);
569 static struct nf_conn *
570 __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
571 const struct nf_conntrack_tuple *repl,
572 const struct nf_conntrack_l3proto *l3proto,
575 struct nf_conn *conntrack = NULL;
576 struct nf_conntrack_helper *helper;
578 if (unlikely(!nf_conntrack_hash_rnd_initted)) {
579 get_random_bytes(&nf_conntrack_hash_rnd, 4);
580 nf_conntrack_hash_rnd_initted = 1;
583 /* We don't want any race condition at early drop stage */
584 atomic_inc(&nf_conntrack_count);
587 && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
588 unsigned int hash = hash_conntrack(orig);
589 /* Try dropping from this hash chain. */
590 if (!early_drop(&nf_conntrack_hash[hash])) {
591 atomic_dec(&nf_conntrack_count);
594 "nf_conntrack: table full, dropping"
596 return ERR_PTR(-ENOMEM);
600 /* find features needed by this conntrack. */
601 features |= l3proto->get_features(orig);
603 /* FIXME: protect helper list per RCU */
604 read_lock_bh(&nf_conntrack_lock);
605 helper = __nf_ct_helper_find(repl);
606 /* NAT might want to assign a helper later */
607 if (helper || features & NF_CT_F_NAT)
608 features |= NF_CT_F_HELP;
609 read_unlock_bh(&nf_conntrack_lock);
611 DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
613 read_lock_bh(&nf_ct_cache_lock);
615 if (unlikely(!nf_ct_cache[features].use)) {
616 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
621 conntrack = kmem_cache_alloc(nf_ct_cache[features].cachep, GFP_ATOMIC);
622 if (conntrack == NULL) {
623 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
627 memset(conntrack, 0, nf_ct_cache[features].size);
628 conntrack->features = features;
629 atomic_set(&conntrack->ct_general.use, 1);
630 conntrack->ct_general.destroy = destroy_conntrack;
631 conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
632 conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
633 /* Don't set timer yet: wait for confirmation */
634 init_timer(&conntrack->timeout);
635 conntrack->timeout.data = (unsigned long)conntrack;
636 conntrack->timeout.function = death_by_timeout;
637 read_unlock_bh(&nf_ct_cache_lock);
641 read_unlock_bh(&nf_ct_cache_lock);
642 atomic_dec(&nf_conntrack_count);
646 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
647 const struct nf_conntrack_tuple *repl)
649 struct nf_conntrack_l3proto *l3proto;
651 l3proto = __nf_ct_l3proto_find(orig->src.l3num);
652 return __nf_conntrack_alloc(orig, repl, l3proto, 0);
654 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
656 void nf_conntrack_free(struct nf_conn *conntrack)
658 u_int32_t features = conntrack->features;
659 NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
660 DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
662 kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
663 atomic_dec(&nf_conntrack_count);
665 EXPORT_SYMBOL_GPL(nf_conntrack_free);
667 /* Allocate a new conntrack: we return -ENOMEM if classification
668 failed due to stress. Otherwise it really is unclassifiable. */
669 static struct nf_conntrack_tuple_hash *
670 init_conntrack(const struct nf_conntrack_tuple *tuple,
671 struct nf_conntrack_l3proto *l3proto,
672 struct nf_conntrack_l4proto *l4proto,
674 unsigned int dataoff)
676 struct nf_conn *conntrack;
677 struct nf_conntrack_tuple repl_tuple;
678 struct nf_conntrack_expect *exp;
679 u_int32_t features = 0;
681 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
682 DEBUGP("Can't invert tuple.\n");
686 read_lock_bh(&nf_conntrack_lock);
687 exp = __nf_conntrack_expect_find(tuple);
688 if (exp && exp->helper)
689 features = NF_CT_F_HELP;
690 read_unlock_bh(&nf_conntrack_lock);
692 conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto, features);
693 if (conntrack == NULL || IS_ERR(conntrack)) {
694 DEBUGP("Can't allocate conntrack.\n");
695 return (struct nf_conntrack_tuple_hash *)conntrack;
698 if (!l4proto->new(conntrack, skb, dataoff)) {
699 nf_conntrack_free(conntrack);
700 DEBUGP("init conntrack: can't track with proto module\n");
704 write_lock_bh(&nf_conntrack_lock);
705 exp = find_expectation(tuple);
708 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
710 /* Welcome, Mr. Bond. We've been expecting you... */
711 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
712 conntrack->master = exp->master;
714 nfct_help(conntrack)->helper = exp->helper;
715 #ifdef CONFIG_NF_CONNTRACK_MARK
716 conntrack->mark = exp->master->mark;
718 #ifdef CONFIG_NF_CONNTRACK_SECMARK
719 conntrack->secmark = exp->master->secmark;
721 nf_conntrack_get(&conntrack->master->ct_general);
722 NF_CT_STAT_INC(expect_new);
724 struct nf_conn_help *help = nfct_help(conntrack);
727 help->helper = __nf_ct_helper_find(&repl_tuple);
731 /* Overload tuple linked list to put us in unconfirmed list. */
732 list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
734 write_unlock_bh(&nf_conntrack_lock);
738 exp->expectfn(conntrack, exp);
739 nf_conntrack_expect_put(exp);
742 return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
745 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
746 static inline struct nf_conn *
747 resolve_normal_ct(struct sk_buff *skb,
748 unsigned int dataoff,
751 struct nf_conntrack_l3proto *l3proto,
752 struct nf_conntrack_l4proto *l4proto,
754 enum ip_conntrack_info *ctinfo)
756 struct nf_conntrack_tuple tuple;
757 struct nf_conntrack_tuple_hash *h;
760 if (!nf_ct_get_tuple(skb, (unsigned int)(skb->nh.raw - skb->data),
761 dataoff, l3num, protonum, &tuple, l3proto,
763 DEBUGP("resolve_normal_ct: Can't get tuple\n");
767 /* look for tuple match */
768 h = nf_conntrack_find_get(&tuple, NULL);
770 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
776 ct = nf_ct_tuplehash_to_ctrack(h);
778 /* It exists; we have (non-exclusive) reference. */
779 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
780 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
781 /* Please set reply bit if this packet OK */
784 /* Once we've had two way comms, always ESTABLISHED. */
785 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
786 DEBUGP("nf_conntrack_in: normal packet for %p\n", ct);
787 *ctinfo = IP_CT_ESTABLISHED;
788 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
789 DEBUGP("nf_conntrack_in: related packet for %p\n", ct);
790 *ctinfo = IP_CT_RELATED;
792 DEBUGP("nf_conntrack_in: new packet for %p\n", ct);
797 skb->nfct = &ct->ct_general;
798 skb->nfctinfo = *ctinfo;
803 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
806 enum ip_conntrack_info ctinfo;
807 struct nf_conntrack_l3proto *l3proto;
808 struct nf_conntrack_l4proto *l4proto;
809 unsigned int dataoff;
814 /* Previously seen (loopback or untracked)? Ignore. */
816 NF_CT_STAT_INC(ignore);
820 l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
821 if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) {
822 DEBUGP("not prepared to track yet or error occured\n");
826 l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
828 /* It may be an special packet, error, unclean...
829 * inverse of the return code tells to the netfilter
830 * core what to do with the packet. */
831 if (l4proto->error != NULL &&
832 (ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
833 NF_CT_STAT_INC(error);
834 NF_CT_STAT_INC(invalid);
838 ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, l4proto,
839 &set_reply, &ctinfo);
841 /* Not valid part of a connection */
842 NF_CT_STAT_INC(invalid);
847 /* Too stressed to deal. */
848 NF_CT_STAT_INC(drop);
852 NF_CT_ASSERT((*pskb)->nfct);
854 ret = l4proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
856 /* Invalid: inverse of the return code tells
857 * the netfilter core what to do */
858 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
859 nf_conntrack_put((*pskb)->nfct);
860 (*pskb)->nfct = NULL;
861 NF_CT_STAT_INC(invalid);
865 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
866 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
870 EXPORT_SYMBOL_GPL(nf_conntrack_in);
872 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
873 const struct nf_conntrack_tuple *orig)
875 return nf_ct_invert_tuple(inverse, orig,
876 __nf_ct_l3proto_find(orig->src.l3num),
877 __nf_ct_l4proto_find(orig->src.l3num,
878 orig->dst.protonum));
880 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
882 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
883 implicitly racy: see __nf_conntrack_confirm */
884 void nf_conntrack_alter_reply(struct nf_conn *ct,
885 const struct nf_conntrack_tuple *newreply)
887 struct nf_conn_help *help = nfct_help(ct);
889 write_lock_bh(&nf_conntrack_lock);
890 /* Should be unconfirmed, so not in hash table yet */
891 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
893 DEBUGP("Altering reply tuple of %p to ", ct);
894 NF_CT_DUMP_TUPLE(newreply);
896 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
897 if (!ct->master && help && help->expecting == 0)
898 help->helper = __nf_ct_helper_find(newreply);
899 write_unlock_bh(&nf_conntrack_lock);
901 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
903 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
904 void __nf_ct_refresh_acct(struct nf_conn *ct,
905 enum ip_conntrack_info ctinfo,
906 const struct sk_buff *skb,
907 unsigned long extra_jiffies,
912 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
915 write_lock_bh(&nf_conntrack_lock);
917 /* Only update if this is not a fixed timeout */
918 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
919 write_unlock_bh(&nf_conntrack_lock);
923 /* If not in hash table, timer will not be active yet */
924 if (!nf_ct_is_confirmed(ct)) {
925 ct->timeout.expires = extra_jiffies;
926 event = IPCT_REFRESH;
928 unsigned long newtime = jiffies + extra_jiffies;
930 /* Only update the timeout if the new timeout is at least
931 HZ jiffies from the old timeout. Need del_timer for race
932 avoidance (may already be dying). */
933 if (newtime - ct->timeout.expires >= HZ
934 && del_timer(&ct->timeout)) {
935 ct->timeout.expires = newtime;
936 add_timer(&ct->timeout);
937 event = IPCT_REFRESH;
941 #ifdef CONFIG_NF_CT_ACCT
943 ct->counters[CTINFO2DIR(ctinfo)].packets++;
944 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
945 skb->len - (unsigned int)(skb->nh.raw - skb->data);
947 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
948 || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
949 event |= IPCT_COUNTER_FILLING;
953 write_unlock_bh(&nf_conntrack_lock);
955 /* must be unlocked when calling event cache */
957 nf_conntrack_event_cache(event, skb);
959 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
961 #if defined(CONFIG_NF_CT_NETLINK) || \
962 defined(CONFIG_NF_CT_NETLINK_MODULE)
964 #include <linux/netfilter/nfnetlink.h>
965 #include <linux/netfilter/nfnetlink_conntrack.h>
966 #include <linux/mutex.h>
969 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
970 * in ip_conntrack_core, since we don't want the protocols to autoload
971 * or depend on ctnetlink */
972 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
973 const struct nf_conntrack_tuple *tuple)
975 NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
976 &tuple->src.u.tcp.port);
977 NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
978 &tuple->dst.u.tcp.port);
984 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr);
986 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
987 [CTA_PROTO_SRC_PORT-1] = sizeof(u_int16_t),
988 [CTA_PROTO_DST_PORT-1] = sizeof(u_int16_t)
991 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
992 struct nf_conntrack_tuple *t)
994 if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
997 if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
1000 t->src.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
1001 t->dst.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
1005 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple);
1008 /* Used by ipt_REJECT and ip6t_REJECT. */
1009 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1012 enum ip_conntrack_info ctinfo;
1014 /* This ICMP is in reverse direction to the packet which caused it */
1015 ct = nf_ct_get(skb, &ctinfo);
1016 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1017 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
1019 ctinfo = IP_CT_RELATED;
1021 /* Attach to new skbuff, and increment count */
1022 nskb->nfct = &ct->ct_general;
1023 nskb->nfctinfo = ctinfo;
1024 nf_conntrack_get(nskb->nfct);
1026 EXPORT_SYMBOL_GPL(__nf_conntrack_attach);
1029 do_iter(const struct nf_conntrack_tuple_hash *i,
1030 int (*iter)(struct nf_conn *i, void *data),
1033 return iter(nf_ct_tuplehash_to_ctrack(i), data);
1036 /* Bring out ya dead! */
1037 static struct nf_conn *
1038 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
1039 void *data, unsigned int *bucket)
1041 struct nf_conntrack_tuple_hash *h;
1044 write_lock_bh(&nf_conntrack_lock);
1045 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1046 list_for_each_entry(h, &nf_conntrack_hash[*bucket], list) {
1047 ct = nf_ct_tuplehash_to_ctrack(h);
1052 list_for_each_entry(h, &unconfirmed, list) {
1053 ct = nf_ct_tuplehash_to_ctrack(h);
1057 write_unlock_bh(&nf_conntrack_lock);
1060 atomic_inc(&ct->ct_general.use);
1061 write_unlock_bh(&nf_conntrack_lock);
1066 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
1069 unsigned int bucket = 0;
1071 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1072 /* Time to push up daises... */
1073 if (del_timer(&ct->timeout))
1074 death_by_timeout((unsigned long)ct);
1075 /* ... else the timer will get him soon. */
1080 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1082 static int kill_all(struct nf_conn *i, void *data)
1087 static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
1092 free_pages((unsigned long)hash,
1093 get_order(sizeof(struct list_head) * size));
1096 void nf_conntrack_flush()
1098 nf_ct_iterate_cleanup(kill_all, NULL);
1100 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1102 /* Mishearing the voices in his head, our hero wonders how he's
1103 supposed to kill the mall. */
1104 void nf_conntrack_cleanup(void)
1108 ip_ct_attach = NULL;
1110 /* This makes sure all current packets have passed through
1111 netfilter framework. Roll on, two-stage module
1115 nf_ct_event_cache_flush();
1117 nf_conntrack_flush();
1118 if (atomic_read(&nf_conntrack_count) != 0) {
1120 goto i_see_dead_people;
1122 /* wait until all references to nf_conntrack_untracked are dropped */
1123 while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1126 for (i = 0; i < NF_CT_F_NUM; i++) {
1127 if (nf_ct_cache[i].use == 0)
1130 NF_CT_ASSERT(nf_ct_cache[i].use == 1);
1131 nf_ct_cache[i].use = 1;
1132 nf_conntrack_unregister_cache(i);
1134 kmem_cache_destroy(nf_conntrack_expect_cachep);
1135 free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1136 nf_conntrack_htable_size);
1138 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_generic);
1140 /* free l3proto protocol tables */
1141 for (i = 0; i < PF_MAX; i++)
1142 if (nf_ct_protos[i]) {
1143 kfree(nf_ct_protos[i]);
1144 nf_ct_protos[i] = NULL;
1148 static struct list_head *alloc_hashtable(int size, int *vmalloced)
1150 struct list_head *hash;
1154 hash = (void*)__get_free_pages(GFP_KERNEL,
1155 get_order(sizeof(struct list_head)
1159 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1160 hash = vmalloc(sizeof(struct list_head) * size);
1164 for (i = 0; i < size; i++)
1165 INIT_LIST_HEAD(&hash[i]);
1170 int set_hashsize(const char *val, struct kernel_param *kp)
1172 int i, bucket, hashsize, vmalloced;
1173 int old_vmalloced, old_size;
1175 struct list_head *hash, *old_hash;
1176 struct nf_conntrack_tuple_hash *h;
1178 /* On boot, we can set this without any fancy locking. */
1179 if (!nf_conntrack_htable_size)
1180 return param_set_uint(val, kp);
1182 hashsize = simple_strtol(val, NULL, 0);
1186 hash = alloc_hashtable(hashsize, &vmalloced);
1190 /* We have to rehahs for the new table anyway, so we also can
1191 * use a newrandom seed */
1192 get_random_bytes(&rnd, 4);
1194 write_lock_bh(&nf_conntrack_lock);
1195 for (i = 0; i < nf_conntrack_htable_size; i++) {
1196 while (!list_empty(&nf_conntrack_hash[i])) {
1197 h = list_entry(nf_conntrack_hash[i].next,
1198 struct nf_conntrack_tuple_hash, list);
1200 bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1201 list_add_tail(&h->list, &hash[bucket]);
1204 old_size = nf_conntrack_htable_size;
1205 old_vmalloced = nf_conntrack_vmalloc;
1206 old_hash = nf_conntrack_hash;
1208 nf_conntrack_htable_size = hashsize;
1209 nf_conntrack_vmalloc = vmalloced;
1210 nf_conntrack_hash = hash;
1211 nf_conntrack_hash_rnd = rnd;
1212 write_unlock_bh(&nf_conntrack_lock);
1214 free_conntrack_hash(old_hash, old_vmalloced, old_size);
1218 module_param_call(hashsize, set_hashsize, param_get_uint,
1219 &nf_conntrack_htable_size, 0600);
1221 int __init nf_conntrack_init(void)
1226 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1227 * machine has 256 buckets. >= 1GB machines have 8192 buckets. */
1228 if (!nf_conntrack_htable_size) {
1229 nf_conntrack_htable_size
1230 = (((num_physpages << PAGE_SHIFT) / 16384)
1231 / sizeof(struct list_head));
1232 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1233 nf_conntrack_htable_size = 8192;
1234 if (nf_conntrack_htable_size < 16)
1235 nf_conntrack_htable_size = 16;
1237 nf_conntrack_max = 8 * nf_conntrack_htable_size;
1239 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1240 NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1243 nf_conntrack_hash = alloc_hashtable(nf_conntrack_htable_size,
1244 &nf_conntrack_vmalloc);
1245 if (!nf_conntrack_hash) {
1246 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1250 ret = nf_conntrack_register_cache(NF_CT_F_BASIC, "nf_conntrack:basic",
1251 sizeof(struct nf_conn));
1253 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1257 nf_conntrack_expect_cachep = kmem_cache_create("nf_conntrack_expect",
1258 sizeof(struct nf_conntrack_expect),
1260 if (!nf_conntrack_expect_cachep) {
1261 printk(KERN_ERR "Unable to create nf_expect slab cache\n");
1262 goto err_free_conntrack_slab;
1265 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_generic);
1267 goto out_free_expect_slab;
1269 /* Don't NEED lock here, but good form anyway. */
1270 write_lock_bh(&nf_conntrack_lock);
1271 for (i = 0; i < AF_MAX; i++)
1272 nf_ct_l3protos[i] = &nf_conntrack_l3proto_generic;
1273 write_unlock_bh(&nf_conntrack_lock);
1275 /* For use by REJECT target */
1276 ip_ct_attach = __nf_conntrack_attach;
1278 /* Set up fake conntrack:
1279 - to never be deleted, not in any hashes */
1280 atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1281 /* - and look it like as a confirmed connection */
1282 set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1286 out_free_expect_slab:
1287 kmem_cache_destroy(nf_conntrack_expect_cachep);
1288 err_free_conntrack_slab:
1289 nf_conntrack_unregister_cache(NF_CT_F_BASIC);
1291 free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1292 nf_conntrack_htable_size);