1 /* Connection state tracking for netfilter. This is separated from,
2 but required by, the NAT layer; it can also be used by an iptables
5 /* (C) 1999-2001 Paul `Rusty' Russell
6 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
7 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/types.h>
15 #include <linux/netfilter.h>
16 #include <linux/module.h>
17 #include <linux/skbuff.h>
18 #include <linux/proc_fs.h>
19 #include <linux/vmalloc.h>
20 #include <linux/stddef.h>
21 #include <linux/slab.h>
22 #include <linux/random.h>
23 #include <linux/jhash.h>
24 #include <linux/err.h>
25 #include <linux/percpu.h>
26 #include <linux/moduleparam.h>
27 #include <linux/notifier.h>
28 #include <linux/kernel.h>
29 #include <linux/netdevice.h>
30 #include <linux/socket.h>
33 #include <net/netfilter/nf_conntrack.h>
34 #include <net/netfilter/nf_conntrack_l3proto.h>
35 #include <net/netfilter/nf_conntrack_l4proto.h>
36 #include <net/netfilter/nf_conntrack_expect.h>
37 #include <net/netfilter/nf_conntrack_helper.h>
38 #include <net/netfilter/nf_conntrack_core.h>
39 #include <net/netfilter/nf_conntrack_extend.h>
41 #define NF_CONNTRACK_VERSION "0.5.0"
43 DEFINE_RWLOCK(nf_conntrack_lock);
44 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
46 /* nf_conntrack_standalone needs this */
47 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
48 EXPORT_SYMBOL_GPL(nf_conntrack_count);
50 unsigned int nf_conntrack_htable_size __read_mostly;
51 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
53 int nf_conntrack_max __read_mostly;
54 EXPORT_SYMBOL_GPL(nf_conntrack_max);
56 struct hlist_head *nf_conntrack_hash __read_mostly;
57 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
59 struct nf_conn nf_conntrack_untracked __read_mostly;
60 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
62 unsigned int nf_ct_log_invalid __read_mostly;
63 HLIST_HEAD(unconfirmed);
64 static int nf_conntrack_vmalloc __read_mostly;
65 static struct kmem_cache *nf_conntrack_cachep __read_mostly;
66 static unsigned int nf_conntrack_next_id;
68 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
69 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
71 static int nf_conntrack_hash_rnd_initted;
72 static unsigned int nf_conntrack_hash_rnd;
74 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
75 unsigned int size, unsigned int rnd)
79 a = jhash2(tuple->src.u3.all, ARRAY_SIZE(tuple->src.u3.all),
80 (tuple->src.l3num << 16) | tuple->dst.protonum);
81 b = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),
82 (tuple->src.u.all << 16) | tuple->dst.u.all);
84 return jhash_2words(a, b, rnd) % size;
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 NF_CT_TUPLE_U_BLANK(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);
117 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
118 const struct nf_conntrack_tuple *orig,
119 const struct nf_conntrack_l3proto *l3proto,
120 const struct nf_conntrack_l4proto *l4proto)
122 NF_CT_TUPLE_U_BLANK(inverse);
124 inverse->src.l3num = orig->src.l3num;
125 if (l3proto->invert_tuple(inverse, orig) == 0)
128 inverse->dst.dir = !orig->dst.dir;
130 inverse->dst.protonum = orig->dst.protonum;
131 return l4proto->invert_tuple(inverse, orig);
133 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
136 clean_from_lists(struct nf_conn *ct)
138 pr_debug("clean_from_lists(%p)\n", ct);
139 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
140 hlist_del(&ct->tuplehash[IP_CT_DIR_REPLY].hnode);
142 /* Destroy all pending expectations */
143 nf_ct_remove_expectations(ct);
147 destroy_conntrack(struct nf_conntrack *nfct)
149 struct nf_conn *ct = (struct nf_conn *)nfct;
150 struct nf_conntrack_l4proto *l4proto;
152 pr_debug("destroy_conntrack(%p)\n", ct);
153 NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
154 NF_CT_ASSERT(!timer_pending(&ct->timeout));
156 nf_conntrack_event(IPCT_DESTROY, ct);
157 set_bit(IPS_DYING_BIT, &ct->status);
159 /* To make sure we don't get any weird locking issues here:
160 * destroy_conntrack() MUST NOT be called with a write lock
161 * to nf_conntrack_lock!!! -HW */
163 l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num,
164 ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
165 if (l4proto && l4proto->destroy)
166 l4proto->destroy(ct);
168 nf_ct_ext_destroy(ct);
172 write_lock_bh(&nf_conntrack_lock);
173 /* Expectations will have been removed in clean_from_lists,
174 * except TFTP can create an expectation on the first packet,
175 * before connection is in the list, so we need to clean here,
177 nf_ct_remove_expectations(ct);
179 /* We overload first tuple to link into unconfirmed list. */
180 if (!nf_ct_is_confirmed(ct)) {
181 BUG_ON(hlist_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode));
182 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
185 NF_CT_STAT_INC(delete);
186 write_unlock_bh(&nf_conntrack_lock);
189 nf_ct_put(ct->master);
191 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
192 nf_conntrack_free(ct);
195 static void death_by_timeout(unsigned long ul_conntrack)
197 struct nf_conn *ct = (void *)ul_conntrack;
198 struct nf_conn_help *help = nfct_help(ct);
199 struct nf_conntrack_helper *helper;
203 helper = rcu_dereference(help->helper);
204 if (helper && helper->destroy)
209 write_lock_bh(&nf_conntrack_lock);
210 /* Inside lock so preempt is disabled on module removal path.
211 * Otherwise we can get spurious warnings. */
212 NF_CT_STAT_INC(delete_list);
213 clean_from_lists(ct);
214 write_unlock_bh(&nf_conntrack_lock);
218 struct nf_conntrack_tuple_hash *
219 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
220 const struct nf_conn *ignored_conntrack)
222 struct nf_conntrack_tuple_hash *h;
223 struct hlist_node *n;
224 unsigned int hash = hash_conntrack(tuple);
226 hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode) {
227 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
228 nf_ct_tuple_equal(tuple, &h->tuple)) {
229 NF_CT_STAT_INC(found);
232 NF_CT_STAT_INC(searched);
237 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
239 /* Find a connection corresponding to a tuple. */
240 struct nf_conntrack_tuple_hash *
241 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple)
243 struct nf_conntrack_tuple_hash *h;
245 read_lock_bh(&nf_conntrack_lock);
246 h = __nf_conntrack_find(tuple, NULL);
248 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
249 read_unlock_bh(&nf_conntrack_lock);
253 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
255 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
257 unsigned int repl_hash)
259 ct->id = ++nf_conntrack_next_id;
260 hlist_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
261 &nf_conntrack_hash[hash]);
262 hlist_add_head(&ct->tuplehash[IP_CT_DIR_REPLY].hnode,
263 &nf_conntrack_hash[repl_hash]);
266 void nf_conntrack_hash_insert(struct nf_conn *ct)
268 unsigned int hash, repl_hash;
270 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
271 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
273 write_lock_bh(&nf_conntrack_lock);
274 __nf_conntrack_hash_insert(ct, hash, repl_hash);
275 write_unlock_bh(&nf_conntrack_lock);
277 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
279 /* Confirm a connection given skb; places it in hash table */
281 __nf_conntrack_confirm(struct sk_buff **pskb)
283 unsigned int hash, repl_hash;
284 struct nf_conntrack_tuple_hash *h;
286 struct nf_conn_help *help;
287 struct hlist_node *n;
288 enum ip_conntrack_info ctinfo;
290 ct = nf_ct_get(*pskb, &ctinfo);
292 /* ipt_REJECT uses nf_conntrack_attach to attach related
293 ICMP/TCP RST packets in other direction. Actual packet
294 which created connection will be IP_CT_NEW or for an
295 expected connection, IP_CT_RELATED. */
296 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
299 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
300 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
302 /* We're not in hash table, and we refuse to set up related
303 connections for unconfirmed conns. But packet copies and
304 REJECT will give spurious warnings here. */
305 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
307 /* No external references means noone else could have
309 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
310 pr_debug("Confirming conntrack %p\n", ct);
312 write_lock_bh(&nf_conntrack_lock);
314 /* See if there's one in the list already, including reverse:
315 NAT could have grabbed it without realizing, since we're
316 not in the hash. If there is, we lost race. */
317 hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode)
318 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
321 hlist_for_each_entry(h, n, &nf_conntrack_hash[repl_hash], hnode)
322 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
326 /* Remove from unconfirmed list */
327 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
329 __nf_conntrack_hash_insert(ct, hash, repl_hash);
330 /* Timer relative to confirmation time, not original
331 setting time, otherwise we'd get timer wrap in
332 weird delay cases. */
333 ct->timeout.expires += jiffies;
334 add_timer(&ct->timeout);
335 atomic_inc(&ct->ct_general.use);
336 set_bit(IPS_CONFIRMED_BIT, &ct->status);
337 NF_CT_STAT_INC(insert);
338 write_unlock_bh(&nf_conntrack_lock);
339 help = nfct_help(ct);
340 if (help && help->helper)
341 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
342 #ifdef CONFIG_NF_NAT_NEEDED
343 if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
344 test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
345 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
347 nf_conntrack_event_cache(master_ct(ct) ?
348 IPCT_RELATED : IPCT_NEW, *pskb);
352 NF_CT_STAT_INC(insert_failed);
353 write_unlock_bh(&nf_conntrack_lock);
356 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
358 /* Returns true if a connection correspondings to the tuple (required
361 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
362 const struct nf_conn *ignored_conntrack)
364 struct nf_conntrack_tuple_hash *h;
366 read_lock_bh(&nf_conntrack_lock);
367 h = __nf_conntrack_find(tuple, ignored_conntrack);
368 read_unlock_bh(&nf_conntrack_lock);
372 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
374 #define NF_CT_EVICTION_RANGE 8
376 /* There's a small race here where we may free a just-assured
377 connection. Too bad: we're in trouble anyway. */
378 static int early_drop(unsigned int hash)
380 /* Use oldest entry, which is roughly LRU */
381 struct nf_conntrack_tuple_hash *h;
382 struct nf_conn *ct = NULL, *tmp;
383 struct hlist_node *n;
384 unsigned int i, cnt = 0;
387 read_lock_bh(&nf_conntrack_lock);
388 for (i = 0; i < nf_conntrack_htable_size; i++) {
389 hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode) {
390 tmp = nf_ct_tuplehash_to_ctrack(h);
391 if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
395 if (ct || cnt >= NF_CT_EVICTION_RANGE)
397 hash = (hash + 1) % nf_conntrack_htable_size;
400 atomic_inc(&ct->ct_general.use);
401 read_unlock_bh(&nf_conntrack_lock);
406 if (del_timer(&ct->timeout)) {
407 death_by_timeout((unsigned long)ct);
409 NF_CT_STAT_INC_ATOMIC(early_drop);
415 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
416 const struct nf_conntrack_tuple *repl)
418 struct nf_conn *conntrack = NULL;
420 if (unlikely(!nf_conntrack_hash_rnd_initted)) {
421 get_random_bytes(&nf_conntrack_hash_rnd, 4);
422 nf_conntrack_hash_rnd_initted = 1;
425 /* We don't want any race condition at early drop stage */
426 atomic_inc(&nf_conntrack_count);
429 && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
430 unsigned int hash = hash_conntrack(orig);
431 if (!early_drop(hash)) {
432 atomic_dec(&nf_conntrack_count);
435 "nf_conntrack: table full, dropping"
437 return ERR_PTR(-ENOMEM);
441 conntrack = kmem_cache_zalloc(nf_conntrack_cachep, GFP_ATOMIC);
442 if (conntrack == NULL) {
443 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
444 atomic_dec(&nf_conntrack_count);
445 return ERR_PTR(-ENOMEM);
448 atomic_set(&conntrack->ct_general.use, 1);
449 conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
450 conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
451 /* Don't set timer yet: wait for confirmation */
452 setup_timer(&conntrack->timeout, death_by_timeout,
453 (unsigned long)conntrack);
457 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
459 void nf_conntrack_free(struct nf_conn *conntrack)
461 nf_ct_ext_free(conntrack);
462 kmem_cache_free(nf_conntrack_cachep, conntrack);
463 atomic_dec(&nf_conntrack_count);
465 EXPORT_SYMBOL_GPL(nf_conntrack_free);
467 /* Allocate a new conntrack: we return -ENOMEM if classification
468 failed due to stress. Otherwise it really is unclassifiable. */
469 static struct nf_conntrack_tuple_hash *
470 init_conntrack(const struct nf_conntrack_tuple *tuple,
471 struct nf_conntrack_l3proto *l3proto,
472 struct nf_conntrack_l4proto *l4proto,
474 unsigned int dataoff)
476 struct nf_conn *conntrack;
477 struct nf_conn_help *help;
478 struct nf_conntrack_tuple repl_tuple;
479 struct nf_conntrack_expect *exp;
481 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
482 pr_debug("Can't invert tuple.\n");
486 conntrack = nf_conntrack_alloc(tuple, &repl_tuple);
487 if (conntrack == NULL || IS_ERR(conntrack)) {
488 pr_debug("Can't allocate conntrack.\n");
489 return (struct nf_conntrack_tuple_hash *)conntrack;
492 if (!l4proto->new(conntrack, skb, dataoff)) {
493 nf_conntrack_free(conntrack);
494 pr_debug("init conntrack: can't track with proto module\n");
498 write_lock_bh(&nf_conntrack_lock);
499 exp = nf_ct_find_expectation(tuple);
501 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
503 /* Welcome, Mr. Bond. We've been expecting you... */
504 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
505 conntrack->master = exp->master;
507 help = nf_ct_helper_ext_add(conntrack, GFP_ATOMIC);
509 rcu_assign_pointer(help->helper, exp->helper);
512 #ifdef CONFIG_NF_CONNTRACK_MARK
513 conntrack->mark = exp->master->mark;
515 #ifdef CONFIG_NF_CONNTRACK_SECMARK
516 conntrack->secmark = exp->master->secmark;
518 nf_conntrack_get(&conntrack->master->ct_general);
519 NF_CT_STAT_INC(expect_new);
521 struct nf_conntrack_helper *helper;
523 helper = __nf_ct_helper_find(&repl_tuple);
525 help = nf_ct_helper_ext_add(conntrack, GFP_ATOMIC);
527 rcu_assign_pointer(help->helper, helper);
532 /* Overload tuple linked list to put us in unconfirmed list. */
533 hlist_add_head(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
536 write_unlock_bh(&nf_conntrack_lock);
540 exp->expectfn(conntrack, exp);
541 nf_ct_expect_put(exp);
544 return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
547 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
548 static inline struct nf_conn *
549 resolve_normal_ct(struct sk_buff *skb,
550 unsigned int dataoff,
553 struct nf_conntrack_l3proto *l3proto,
554 struct nf_conntrack_l4proto *l4proto,
556 enum ip_conntrack_info *ctinfo)
558 struct nf_conntrack_tuple tuple;
559 struct nf_conntrack_tuple_hash *h;
562 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
563 dataoff, l3num, protonum, &tuple, l3proto,
565 pr_debug("resolve_normal_ct: Can't get tuple\n");
569 /* look for tuple match */
570 h = nf_conntrack_find_get(&tuple);
572 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
578 ct = nf_ct_tuplehash_to_ctrack(h);
580 /* It exists; we have (non-exclusive) reference. */
581 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
582 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
583 /* Please set reply bit if this packet OK */
586 /* Once we've had two way comms, always ESTABLISHED. */
587 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
588 pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
589 *ctinfo = IP_CT_ESTABLISHED;
590 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
591 pr_debug("nf_conntrack_in: related packet for %p\n",
593 *ctinfo = IP_CT_RELATED;
595 pr_debug("nf_conntrack_in: new packet for %p\n", ct);
600 skb->nfct = &ct->ct_general;
601 skb->nfctinfo = *ctinfo;
606 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
609 enum ip_conntrack_info ctinfo;
610 struct nf_conntrack_l3proto *l3proto;
611 struct nf_conntrack_l4proto *l4proto;
612 unsigned int dataoff;
617 /* Previously seen (loopback or untracked)? Ignore. */
619 NF_CT_STAT_INC_ATOMIC(ignore);
623 /* rcu_read_lock()ed by nf_hook_slow */
624 l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
626 if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) {
627 pr_debug("not prepared to track yet or error occured\n");
631 l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
633 /* It may be an special packet, error, unclean...
634 * inverse of the return code tells to the netfilter
635 * core what to do with the packet. */
636 if (l4proto->error != NULL &&
637 (ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
638 NF_CT_STAT_INC_ATOMIC(error);
639 NF_CT_STAT_INC_ATOMIC(invalid);
643 ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, l4proto,
644 &set_reply, &ctinfo);
646 /* Not valid part of a connection */
647 NF_CT_STAT_INC_ATOMIC(invalid);
652 /* Too stressed to deal. */
653 NF_CT_STAT_INC_ATOMIC(drop);
657 NF_CT_ASSERT((*pskb)->nfct);
659 ret = l4proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
661 /* Invalid: inverse of the return code tells
662 * the netfilter core what to do */
663 pr_debug("nf_conntrack_in: Can't track with proto module\n");
664 nf_conntrack_put((*pskb)->nfct);
665 (*pskb)->nfct = NULL;
666 NF_CT_STAT_INC_ATOMIC(invalid);
670 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
671 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
675 EXPORT_SYMBOL_GPL(nf_conntrack_in);
677 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
678 const struct nf_conntrack_tuple *orig)
683 ret = nf_ct_invert_tuple(inverse, orig,
684 __nf_ct_l3proto_find(orig->src.l3num),
685 __nf_ct_l4proto_find(orig->src.l3num,
686 orig->dst.protonum));
690 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
692 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
693 implicitly racy: see __nf_conntrack_confirm */
694 void nf_conntrack_alter_reply(struct nf_conn *ct,
695 const struct nf_conntrack_tuple *newreply)
697 struct nf_conn_help *help = nfct_help(ct);
698 struct nf_conntrack_helper *helper;
700 write_lock_bh(&nf_conntrack_lock);
701 /* Should be unconfirmed, so not in hash table yet */
702 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
704 pr_debug("Altering reply tuple of %p to ", ct);
705 NF_CT_DUMP_TUPLE(newreply);
707 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
708 if (ct->master || (help && help->expecting != 0))
711 helper = __nf_ct_helper_find(newreply);
712 if (helper == NULL) {
714 rcu_assign_pointer(help->helper, NULL);
719 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
723 memset(&help->help, 0, sizeof(help->help));
726 rcu_assign_pointer(help->helper, helper);
728 write_unlock_bh(&nf_conntrack_lock);
730 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
732 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
733 void __nf_ct_refresh_acct(struct nf_conn *ct,
734 enum ip_conntrack_info ctinfo,
735 const struct sk_buff *skb,
736 unsigned long extra_jiffies,
741 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
744 write_lock_bh(&nf_conntrack_lock);
746 /* Only update if this is not a fixed timeout */
747 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
748 write_unlock_bh(&nf_conntrack_lock);
752 /* If not in hash table, timer will not be active yet */
753 if (!nf_ct_is_confirmed(ct)) {
754 ct->timeout.expires = extra_jiffies;
755 event = IPCT_REFRESH;
757 unsigned long newtime = jiffies + extra_jiffies;
759 /* Only update the timeout if the new timeout is at least
760 HZ jiffies from the old timeout. Need del_timer for race
761 avoidance (may already be dying). */
762 if (newtime - ct->timeout.expires >= HZ
763 && del_timer(&ct->timeout)) {
764 ct->timeout.expires = newtime;
765 add_timer(&ct->timeout);
766 event = IPCT_REFRESH;
770 #ifdef CONFIG_NF_CT_ACCT
772 ct->counters[CTINFO2DIR(ctinfo)].packets++;
773 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
774 skb->len - skb_network_offset(skb);
776 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
777 || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
778 event |= IPCT_COUNTER_FILLING;
782 write_unlock_bh(&nf_conntrack_lock);
784 /* must be unlocked when calling event cache */
786 nf_conntrack_event_cache(event, skb);
788 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
790 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
792 #include <linux/netfilter/nfnetlink.h>
793 #include <linux/netfilter/nfnetlink_conntrack.h>
794 #include <linux/mutex.h>
797 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
798 * in ip_conntrack_core, since we don't want the protocols to autoload
799 * or depend on ctnetlink */
800 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
801 const struct nf_conntrack_tuple *tuple)
803 NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
804 &tuple->src.u.tcp.port);
805 NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
806 &tuple->dst.u.tcp.port);
812 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr);
814 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
815 [CTA_PROTO_SRC_PORT-1] = sizeof(u_int16_t),
816 [CTA_PROTO_DST_PORT-1] = sizeof(u_int16_t)
819 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
820 struct nf_conntrack_tuple *t)
822 if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
825 if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
828 t->src.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
829 t->dst.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
833 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple);
836 /* Used by ipt_REJECT and ip6t_REJECT. */
837 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
840 enum ip_conntrack_info ctinfo;
842 /* This ICMP is in reverse direction to the packet which caused it */
843 ct = nf_ct_get(skb, &ctinfo);
844 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
845 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
847 ctinfo = IP_CT_RELATED;
849 /* Attach to new skbuff, and increment count */
850 nskb->nfct = &ct->ct_general;
851 nskb->nfctinfo = ctinfo;
852 nf_conntrack_get(nskb->nfct);
854 EXPORT_SYMBOL_GPL(__nf_conntrack_attach);
857 do_iter(const struct nf_conntrack_tuple_hash *i,
858 int (*iter)(struct nf_conn *i, void *data),
861 return iter(nf_ct_tuplehash_to_ctrack(i), data);
864 /* Bring out ya dead! */
865 static struct nf_conn *
866 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
867 void *data, unsigned int *bucket)
869 struct nf_conntrack_tuple_hash *h;
871 struct hlist_node *n;
873 write_lock_bh(&nf_conntrack_lock);
874 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
875 hlist_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnode) {
876 ct = nf_ct_tuplehash_to_ctrack(h);
881 hlist_for_each_entry(h, n, &unconfirmed, hnode) {
882 ct = nf_ct_tuplehash_to_ctrack(h);
884 set_bit(IPS_DYING_BIT, &ct->status);
886 write_unlock_bh(&nf_conntrack_lock);
889 atomic_inc(&ct->ct_general.use);
890 write_unlock_bh(&nf_conntrack_lock);
895 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
898 unsigned int bucket = 0;
900 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
901 /* Time to push up daises... */
902 if (del_timer(&ct->timeout))
903 death_by_timeout((unsigned long)ct);
904 /* ... else the timer will get him soon. */
909 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
911 static int kill_all(struct nf_conn *i, void *data)
916 void nf_ct_free_hashtable(struct hlist_head *hash, int vmalloced, int size)
921 free_pages((unsigned long)hash,
922 get_order(sizeof(struct hlist_head) * size));
924 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
926 void nf_conntrack_flush(void)
928 nf_ct_iterate_cleanup(kill_all, NULL);
930 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
932 /* Mishearing the voices in his head, our hero wonders how he's
933 supposed to kill the mall. */
934 void nf_conntrack_cleanup(void)
936 rcu_assign_pointer(ip_ct_attach, NULL);
938 /* This makes sure all current packets have passed through
939 netfilter framework. Roll on, two-stage module
943 nf_ct_event_cache_flush();
945 nf_conntrack_flush();
946 if (atomic_read(&nf_conntrack_count) != 0) {
948 goto i_see_dead_people;
950 /* wait until all references to nf_conntrack_untracked are dropped */
951 while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
954 rcu_assign_pointer(nf_ct_destroy, NULL);
956 kmem_cache_destroy(nf_conntrack_cachep);
957 nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
958 nf_conntrack_htable_size);
960 nf_conntrack_proto_fini();
961 nf_conntrack_helper_fini();
962 nf_conntrack_expect_fini();
965 struct hlist_head *nf_ct_alloc_hashtable(int *sizep, int *vmalloced)
967 struct hlist_head *hash;
968 unsigned int size, i;
972 size = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_head));
973 hash = (void*)__get_free_pages(GFP_KERNEL,
974 get_order(sizeof(struct hlist_head)
978 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
979 hash = vmalloc(sizeof(struct hlist_head) * size);
983 for (i = 0; i < size; i++)
984 INIT_HLIST_HEAD(&hash[i]);
988 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
990 int set_hashsize(const char *val, struct kernel_param *kp)
992 int i, bucket, hashsize, vmalloced;
993 int old_vmalloced, old_size;
995 struct hlist_head *hash, *old_hash;
996 struct nf_conntrack_tuple_hash *h;
998 /* On boot, we can set this without any fancy locking. */
999 if (!nf_conntrack_htable_size)
1000 return param_set_uint(val, kp);
1002 hashsize = simple_strtol(val, NULL, 0);
1006 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced);
1010 /* We have to rehahs for the new table anyway, so we also can
1011 * use a newrandom seed */
1012 get_random_bytes(&rnd, 4);
1014 write_lock_bh(&nf_conntrack_lock);
1015 for (i = 0; i < nf_conntrack_htable_size; i++) {
1016 while (!hlist_empty(&nf_conntrack_hash[i])) {
1017 h = hlist_entry(nf_conntrack_hash[i].first,
1018 struct nf_conntrack_tuple_hash, hnode);
1019 hlist_del(&h->hnode);
1020 bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1021 hlist_add_head(&h->hnode, &hash[bucket]);
1024 old_size = nf_conntrack_htable_size;
1025 old_vmalloced = nf_conntrack_vmalloc;
1026 old_hash = nf_conntrack_hash;
1028 nf_conntrack_htable_size = hashsize;
1029 nf_conntrack_vmalloc = vmalloced;
1030 nf_conntrack_hash = hash;
1031 nf_conntrack_hash_rnd = rnd;
1032 write_unlock_bh(&nf_conntrack_lock);
1034 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1038 module_param_call(hashsize, set_hashsize, param_get_uint,
1039 &nf_conntrack_htable_size, 0600);
1041 int __init nf_conntrack_init(void)
1046 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1047 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1048 if (!nf_conntrack_htable_size) {
1049 nf_conntrack_htable_size
1050 = (((num_physpages << PAGE_SHIFT) / 16384)
1051 / sizeof(struct hlist_head));
1052 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1053 nf_conntrack_htable_size = 16384;
1054 if (nf_conntrack_htable_size < 32)
1055 nf_conntrack_htable_size = 32;
1057 /* Use a max. factor of four by default to get the same max as
1058 * with the old struct list_heads. When a table size is given
1059 * we use the old value of 8 to avoid reducing the max.
1063 nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1064 &nf_conntrack_vmalloc);
1065 if (!nf_conntrack_hash) {
1066 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1070 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1072 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1073 NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1076 nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1077 sizeof(struct nf_conn),
1079 if (!nf_conntrack_cachep) {
1080 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1084 ret = nf_conntrack_proto_init();
1086 goto err_free_conntrack_slab;
1088 ret = nf_conntrack_expect_init();
1090 goto out_fini_proto;
1092 ret = nf_conntrack_helper_init();
1094 goto out_fini_expect;
1096 /* For use by REJECT target */
1097 rcu_assign_pointer(ip_ct_attach, __nf_conntrack_attach);
1098 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1100 /* Set up fake conntrack:
1101 - to never be deleted, not in any hashes */
1102 atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1103 /* - and look it like as a confirmed connection */
1104 set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1109 nf_conntrack_expect_fini();
1111 nf_conntrack_proto_fini();
1112 err_free_conntrack_slab:
1113 kmem_cache_destroy(nf_conntrack_cachep);
1115 nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
1116 nf_conntrack_htable_size);