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_conntrack_ecache.h>
43 #include <net/netfilter/nf_nat.h>
44 #include <net/netfilter/nf_nat_core.h>
46 #define NF_CONNTRACK_VERSION "0.5.0"
48 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
49 enum nf_nat_manip_type manip,
50 struct nlattr *attr) __read_mostly;
51 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
53 DEFINE_SPINLOCK(nf_conntrack_lock);
54 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
56 unsigned int nf_conntrack_htable_size __read_mostly;
57 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
59 unsigned int nf_conntrack_max __read_mostly;
60 EXPORT_SYMBOL_GPL(nf_conntrack_max);
62 struct nf_conn nf_conntrack_untracked __read_mostly;
63 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
65 static struct kmem_cache *nf_conntrack_cachep __read_mostly;
67 static int nf_conntrack_hash_rnd_initted;
68 static unsigned int nf_conntrack_hash_rnd;
70 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
71 unsigned int size, unsigned int rnd)
76 /* The direction must be ignored, so we hash everything up to the
77 * destination ports (which is a multiple of 4) and treat the last
78 * three bytes manually.
80 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
81 h = jhash2((u32 *)tuple, n,
82 rnd ^ (((__force __u16)tuple->dst.u.all << 16) |
83 tuple->dst.protonum));
85 return ((u64)h * size) >> 32;
88 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
90 return __hash_conntrack(tuple, nf_conntrack_htable_size,
91 nf_conntrack_hash_rnd);
95 nf_ct_get_tuple(const struct sk_buff *skb,
100 struct nf_conntrack_tuple *tuple,
101 const struct nf_conntrack_l3proto *l3proto,
102 const struct nf_conntrack_l4proto *l4proto)
104 memset(tuple, 0, sizeof(*tuple));
106 tuple->src.l3num = l3num;
107 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
110 tuple->dst.protonum = protonum;
111 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
113 return l4proto->pkt_to_tuple(skb, dataoff, tuple);
115 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
117 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
118 u_int16_t l3num, struct nf_conntrack_tuple *tuple)
120 struct nf_conntrack_l3proto *l3proto;
121 struct nf_conntrack_l4proto *l4proto;
122 unsigned int protoff;
128 l3proto = __nf_ct_l3proto_find(l3num);
129 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
130 if (ret != NF_ACCEPT) {
135 l4proto = __nf_ct_l4proto_find(l3num, protonum);
137 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
143 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
146 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
147 const struct nf_conntrack_tuple *orig,
148 const struct nf_conntrack_l3proto *l3proto,
149 const struct nf_conntrack_l4proto *l4proto)
151 memset(inverse, 0, sizeof(*inverse));
153 inverse->src.l3num = orig->src.l3num;
154 if (l3proto->invert_tuple(inverse, orig) == 0)
157 inverse->dst.dir = !orig->dst.dir;
159 inverse->dst.protonum = orig->dst.protonum;
160 return l4proto->invert_tuple(inverse, orig);
162 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
165 clean_from_lists(struct nf_conn *ct)
167 pr_debug("clean_from_lists(%p)\n", ct);
168 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
169 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
171 /* Destroy all pending expectations */
172 nf_ct_remove_expectations(ct);
176 destroy_conntrack(struct nf_conntrack *nfct)
178 struct nf_conn *ct = (struct nf_conn *)nfct;
179 struct net *net = nf_ct_net(ct);
180 struct nf_conntrack_l4proto *l4proto;
182 pr_debug("destroy_conntrack(%p)\n", ct);
183 NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
184 NF_CT_ASSERT(!timer_pending(&ct->timeout));
186 /* To make sure we don't get any weird locking issues here:
187 * destroy_conntrack() MUST NOT be called with a write lock
188 * to nf_conntrack_lock!!! -HW */
190 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
191 if (l4proto && l4proto->destroy)
192 l4proto->destroy(ct);
196 spin_lock_bh(&nf_conntrack_lock);
197 /* Expectations will have been removed in clean_from_lists,
198 * except TFTP can create an expectation on the first packet,
199 * before connection is in the list, so we need to clean here,
201 nf_ct_remove_expectations(ct);
203 /* We overload first tuple to link into unconfirmed list. */
204 if (!nf_ct_is_confirmed(ct)) {
205 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
206 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
209 NF_CT_STAT_INC(net, delete);
210 spin_unlock_bh(&nf_conntrack_lock);
213 nf_ct_put(ct->master);
215 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
216 nf_conntrack_free(ct);
219 void nf_ct_delete_from_lists(struct nf_conn *ct)
221 struct net *net = nf_ct_net(ct);
223 nf_ct_helper_destroy(ct);
224 spin_lock_bh(&nf_conntrack_lock);
225 /* Inside lock so preempt is disabled on module removal path.
226 * Otherwise we can get spurious warnings. */
227 NF_CT_STAT_INC(net, delete_list);
228 clean_from_lists(ct);
229 spin_unlock_bh(&nf_conntrack_lock);
231 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
233 static void death_by_event(unsigned long ul_conntrack)
235 struct nf_conn *ct = (void *)ul_conntrack;
236 struct net *net = nf_ct_net(ct);
238 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
239 /* bad luck, let's retry again */
240 ct->timeout.expires = jiffies +
241 (random32() % net->ct.sysctl_events_retry_timeout);
242 add_timer(&ct->timeout);
245 /* we've got the event delivered, now it's dying */
246 set_bit(IPS_DYING_BIT, &ct->status);
247 spin_lock(&nf_conntrack_lock);
248 hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
249 spin_unlock(&nf_conntrack_lock);
253 void nf_ct_insert_dying_list(struct nf_conn *ct)
255 struct net *net = nf_ct_net(ct);
257 /* add this conntrack to the dying list */
258 spin_lock_bh(&nf_conntrack_lock);
259 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
261 spin_unlock_bh(&nf_conntrack_lock);
262 /* set a new timer to retry event delivery */
263 setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
264 ct->timeout.expires = jiffies +
265 (random32() % net->ct.sysctl_events_retry_timeout);
266 add_timer(&ct->timeout);
268 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
270 static void death_by_timeout(unsigned long ul_conntrack)
272 struct nf_conn *ct = (void *)ul_conntrack;
274 if (!test_bit(IPS_DYING_BIT, &ct->status) &&
275 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
276 /* destroy event was not delivered */
277 nf_ct_delete_from_lists(ct);
278 nf_ct_insert_dying_list(ct);
281 set_bit(IPS_DYING_BIT, &ct->status);
282 nf_ct_delete_from_lists(ct);
288 * - Caller must take a reference on returned object
289 * and recheck nf_ct_tuple_equal(tuple, &h->tuple)
291 * - Caller must lock nf_conntrack_lock before calling this function
293 struct nf_conntrack_tuple_hash *
294 __nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple)
296 struct nf_conntrack_tuple_hash *h;
297 struct hlist_nulls_node *n;
298 unsigned int hash = hash_conntrack(tuple);
300 /* Disable BHs the entire time since we normally need to disable them
301 * at least once for the stats anyway.
305 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
306 if (nf_ct_tuple_equal(tuple, &h->tuple)) {
307 NF_CT_STAT_INC(net, found);
311 NF_CT_STAT_INC(net, searched);
314 * if the nulls value we got at the end of this lookup is
315 * not the expected one, we must restart lookup.
316 * We probably met an item that was moved to another chain.
318 if (get_nulls_value(n) != hash)
324 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
326 /* Find a connection corresponding to a tuple. */
327 struct nf_conntrack_tuple_hash *
328 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple)
330 struct nf_conntrack_tuple_hash *h;
335 h = __nf_conntrack_find(net, tuple);
337 ct = nf_ct_tuplehash_to_ctrack(h);
338 if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
341 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) {
351 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
353 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
355 unsigned int repl_hash)
357 struct net *net = nf_ct_net(ct);
359 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
360 &net->ct.hash[hash]);
361 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
362 &net->ct.hash[repl_hash]);
365 void nf_conntrack_hash_insert(struct nf_conn *ct)
367 unsigned int hash, repl_hash;
369 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
370 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
372 __nf_conntrack_hash_insert(ct, hash, repl_hash);
374 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
376 /* Confirm a connection given skb; places it in hash table */
378 __nf_conntrack_confirm(struct sk_buff *skb)
380 unsigned int hash, repl_hash;
381 struct nf_conntrack_tuple_hash *h;
383 struct nf_conn_help *help;
384 struct hlist_nulls_node *n;
385 enum ip_conntrack_info ctinfo;
388 ct = nf_ct_get(skb, &ctinfo);
391 /* ipt_REJECT uses nf_conntrack_attach to attach related
392 ICMP/TCP RST packets in other direction. Actual packet
393 which created connection will be IP_CT_NEW or for an
394 expected connection, IP_CT_RELATED. */
395 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
398 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
399 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
401 /* We're not in hash table, and we refuse to set up related
402 connections for unconfirmed conns. But packet copies and
403 REJECT will give spurious warnings here. */
404 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
406 /* No external references means noone else could have
408 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
409 pr_debug("Confirming conntrack %p\n", ct);
411 spin_lock_bh(&nf_conntrack_lock);
413 /* See if there's one in the list already, including reverse:
414 NAT could have grabbed it without realizing, since we're
415 not in the hash. If there is, we lost race. */
416 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
417 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
420 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
421 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
425 /* Remove from unconfirmed list */
426 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
428 /* Timer relative to confirmation time, not original
429 setting time, otherwise we'd get timer wrap in
430 weird delay cases. */
431 ct->timeout.expires += jiffies;
432 add_timer(&ct->timeout);
433 atomic_inc(&ct->ct_general.use);
434 set_bit(IPS_CONFIRMED_BIT, &ct->status);
436 /* Since the lookup is lockless, hash insertion must be done after
437 * starting the timer and setting the CONFIRMED bit. The RCU barriers
438 * guarantee that no other CPU can find the conntrack before the above
439 * stores are visible.
441 __nf_conntrack_hash_insert(ct, hash, repl_hash);
442 NF_CT_STAT_INC(net, insert);
443 spin_unlock_bh(&nf_conntrack_lock);
445 help = nfct_help(ct);
446 if (help && help->helper)
447 nf_conntrack_event_cache(IPCT_HELPER, ct);
449 nf_conntrack_event_cache(master_ct(ct) ?
450 IPCT_RELATED : IPCT_NEW, ct);
454 NF_CT_STAT_INC(net, insert_failed);
455 spin_unlock_bh(&nf_conntrack_lock);
458 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
460 /* Returns true if a connection correspondings to the tuple (required
463 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
464 const struct nf_conn *ignored_conntrack)
466 struct net *net = nf_ct_net(ignored_conntrack);
467 struct nf_conntrack_tuple_hash *h;
468 struct hlist_nulls_node *n;
469 unsigned int hash = hash_conntrack(tuple);
471 /* Disable BHs the entire time since we need to disable them at
472 * least once for the stats anyway.
475 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
476 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
477 nf_ct_tuple_equal(tuple, &h->tuple)) {
478 NF_CT_STAT_INC(net, found);
479 rcu_read_unlock_bh();
482 NF_CT_STAT_INC(net, searched);
484 rcu_read_unlock_bh();
488 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
490 #define NF_CT_EVICTION_RANGE 8
492 /* There's a small race here where we may free a just-assured
493 connection. Too bad: we're in trouble anyway. */
494 static noinline int early_drop(struct net *net, unsigned int hash)
496 /* Use oldest entry, which is roughly LRU */
497 struct nf_conntrack_tuple_hash *h;
498 struct nf_conn *ct = NULL, *tmp;
499 struct hlist_nulls_node *n;
500 unsigned int i, cnt = 0;
504 for (i = 0; i < nf_conntrack_htable_size; i++) {
505 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
507 tmp = nf_ct_tuplehash_to_ctrack(h);
508 if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
513 if (ct && unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
515 if (ct || cnt >= NF_CT_EVICTION_RANGE)
517 hash = (hash + 1) % nf_conntrack_htable_size;
524 if (del_timer(&ct->timeout)) {
525 death_by_timeout((unsigned long)ct);
527 NF_CT_STAT_INC_ATOMIC(net, early_drop);
533 struct nf_conn *nf_conntrack_alloc(struct net *net,
534 const struct nf_conntrack_tuple *orig,
535 const struct nf_conntrack_tuple *repl,
540 if (unlikely(!nf_conntrack_hash_rnd_initted)) {
541 get_random_bytes(&nf_conntrack_hash_rnd,
542 sizeof(nf_conntrack_hash_rnd));
543 nf_conntrack_hash_rnd_initted = 1;
546 /* We don't want any race condition at early drop stage */
547 atomic_inc(&net->ct.count);
549 if (nf_conntrack_max &&
550 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
551 unsigned int hash = hash_conntrack(orig);
552 if (!early_drop(net, hash)) {
553 atomic_dec(&net->ct.count);
556 "nf_conntrack: table full, dropping"
558 return ERR_PTR(-ENOMEM);
562 ct = kmem_cache_zalloc(nf_conntrack_cachep, gfp);
564 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
565 atomic_dec(&net->ct.count);
566 return ERR_PTR(-ENOMEM);
569 spin_lock_init(&ct->lock);
570 atomic_set(&ct->ct_general.use, 1);
571 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
572 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
573 /* Don't set timer yet: wait for confirmation */
574 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
581 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
583 void nf_conntrack_free(struct nf_conn *ct)
585 struct net *net = nf_ct_net(ct);
587 nf_ct_ext_destroy(ct);
588 atomic_dec(&net->ct.count);
590 kmem_cache_free(nf_conntrack_cachep, ct);
592 EXPORT_SYMBOL_GPL(nf_conntrack_free);
594 /* Allocate a new conntrack: we return -ENOMEM if classification
595 failed due to stress. Otherwise it really is unclassifiable. */
596 static struct nf_conntrack_tuple_hash *
597 init_conntrack(struct net *net,
598 const struct nf_conntrack_tuple *tuple,
599 struct nf_conntrack_l3proto *l3proto,
600 struct nf_conntrack_l4proto *l4proto,
602 unsigned int dataoff)
605 struct nf_conn_help *help;
606 struct nf_conntrack_tuple repl_tuple;
607 struct nf_conntrack_expect *exp;
609 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
610 pr_debug("Can't invert tuple.\n");
614 ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC);
616 pr_debug("Can't allocate conntrack.\n");
617 return (struct nf_conntrack_tuple_hash *)ct;
620 if (!l4proto->new(ct, skb, dataoff)) {
621 nf_conntrack_free(ct);
622 pr_debug("init conntrack: can't track with proto module\n");
626 nf_ct_acct_ext_add(ct, GFP_ATOMIC);
627 nf_ct_ecache_ext_add(ct, GFP_ATOMIC);
629 spin_lock_bh(&nf_conntrack_lock);
630 exp = nf_ct_find_expectation(net, tuple);
632 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
634 /* Welcome, Mr. Bond. We've been expecting you... */
635 __set_bit(IPS_EXPECTED_BIT, &ct->status);
636 ct->master = exp->master;
638 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
640 rcu_assign_pointer(help->helper, exp->helper);
643 #ifdef CONFIG_NF_CONNTRACK_MARK
644 ct->mark = exp->master->mark;
646 #ifdef CONFIG_NF_CONNTRACK_SECMARK
647 ct->secmark = exp->master->secmark;
649 nf_conntrack_get(&ct->master->ct_general);
650 NF_CT_STAT_INC(net, expect_new);
652 __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
653 NF_CT_STAT_INC(net, new);
656 /* Overload tuple linked list to put us in unconfirmed list. */
657 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
658 &net->ct.unconfirmed);
660 spin_unlock_bh(&nf_conntrack_lock);
664 exp->expectfn(ct, exp);
665 nf_ct_expect_put(exp);
668 return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
671 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
672 static inline struct nf_conn *
673 resolve_normal_ct(struct net *net,
675 unsigned int dataoff,
678 struct nf_conntrack_l3proto *l3proto,
679 struct nf_conntrack_l4proto *l4proto,
681 enum ip_conntrack_info *ctinfo)
683 struct nf_conntrack_tuple tuple;
684 struct nf_conntrack_tuple_hash *h;
687 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
688 dataoff, l3num, protonum, &tuple, l3proto,
690 pr_debug("resolve_normal_ct: Can't get tuple\n");
694 /* look for tuple match */
695 h = nf_conntrack_find_get(net, &tuple);
697 h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff);
703 ct = nf_ct_tuplehash_to_ctrack(h);
705 /* It exists; we have (non-exclusive) reference. */
706 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
707 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
708 /* Please set reply bit if this packet OK */
711 /* Once we've had two way comms, always ESTABLISHED. */
712 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
713 pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
714 *ctinfo = IP_CT_ESTABLISHED;
715 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
716 pr_debug("nf_conntrack_in: related packet for %p\n",
718 *ctinfo = IP_CT_RELATED;
720 pr_debug("nf_conntrack_in: new packet for %p\n", ct);
725 skb->nfct = &ct->ct_general;
726 skb->nfctinfo = *ctinfo;
731 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
735 enum ip_conntrack_info ctinfo;
736 struct nf_conntrack_l3proto *l3proto;
737 struct nf_conntrack_l4proto *l4proto;
738 unsigned int dataoff;
743 /* Previously seen (loopback or untracked)? Ignore. */
745 NF_CT_STAT_INC_ATOMIC(net, ignore);
749 /* rcu_read_lock()ed by nf_hook_slow */
750 l3proto = __nf_ct_l3proto_find(pf);
751 ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
752 &dataoff, &protonum);
754 pr_debug("not prepared to track yet or error occured\n");
755 NF_CT_STAT_INC_ATOMIC(net, error);
756 NF_CT_STAT_INC_ATOMIC(net, invalid);
760 l4proto = __nf_ct_l4proto_find(pf, protonum);
762 /* It may be an special packet, error, unclean...
763 * inverse of the return code tells to the netfilter
764 * core what to do with the packet. */
765 if (l4proto->error != NULL) {
766 ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum);
768 NF_CT_STAT_INC_ATOMIC(net, error);
769 NF_CT_STAT_INC_ATOMIC(net, invalid);
774 ct = resolve_normal_ct(net, skb, dataoff, pf, protonum,
775 l3proto, l4proto, &set_reply, &ctinfo);
777 /* Not valid part of a connection */
778 NF_CT_STAT_INC_ATOMIC(net, invalid);
783 /* Too stressed to deal. */
784 NF_CT_STAT_INC_ATOMIC(net, drop);
788 NF_CT_ASSERT(skb->nfct);
790 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
792 /* Invalid: inverse of the return code tells
793 * the netfilter core what to do */
794 pr_debug("nf_conntrack_in: Can't track with proto module\n");
795 nf_conntrack_put(skb->nfct);
797 NF_CT_STAT_INC_ATOMIC(net, invalid);
799 NF_CT_STAT_INC_ATOMIC(net, drop);
803 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
804 nf_conntrack_event_cache(IPCT_STATUS, ct);
808 EXPORT_SYMBOL_GPL(nf_conntrack_in);
810 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
811 const struct nf_conntrack_tuple *orig)
816 ret = nf_ct_invert_tuple(inverse, orig,
817 __nf_ct_l3proto_find(orig->src.l3num),
818 __nf_ct_l4proto_find(orig->src.l3num,
819 orig->dst.protonum));
823 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
825 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
826 implicitly racy: see __nf_conntrack_confirm */
827 void nf_conntrack_alter_reply(struct nf_conn *ct,
828 const struct nf_conntrack_tuple *newreply)
830 struct nf_conn_help *help = nfct_help(ct);
832 /* Should be unconfirmed, so not in hash table yet */
833 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
835 pr_debug("Altering reply tuple of %p to ", ct);
836 nf_ct_dump_tuple(newreply);
838 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
839 if (ct->master || (help && !hlist_empty(&help->expectations)))
843 __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
846 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
848 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
849 void __nf_ct_refresh_acct(struct nf_conn *ct,
850 enum ip_conntrack_info ctinfo,
851 const struct sk_buff *skb,
852 unsigned long extra_jiffies,
855 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
858 /* Only update if this is not a fixed timeout */
859 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
862 /* If not in hash table, timer will not be active yet */
863 if (!nf_ct_is_confirmed(ct)) {
864 ct->timeout.expires = extra_jiffies;
866 unsigned long newtime = jiffies + extra_jiffies;
868 /* Only update the timeout if the new timeout is at least
869 HZ jiffies from the old timeout. Need del_timer for race
870 avoidance (may already be dying). */
871 if (newtime - ct->timeout.expires >= HZ)
872 mod_timer_pending(&ct->timeout, newtime);
877 struct nf_conn_counter *acct;
879 acct = nf_conn_acct_find(ct);
881 spin_lock_bh(&ct->lock);
882 acct[CTINFO2DIR(ctinfo)].packets++;
883 acct[CTINFO2DIR(ctinfo)].bytes +=
884 skb->len - skb_network_offset(skb);
885 spin_unlock_bh(&ct->lock);
889 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
891 bool __nf_ct_kill_acct(struct nf_conn *ct,
892 enum ip_conntrack_info ctinfo,
893 const struct sk_buff *skb,
897 struct nf_conn_counter *acct;
899 acct = nf_conn_acct_find(ct);
901 spin_lock_bh(&ct->lock);
902 acct[CTINFO2DIR(ctinfo)].packets++;
903 acct[CTINFO2DIR(ctinfo)].bytes +=
904 skb->len - skb_network_offset(skb);
905 spin_unlock_bh(&ct->lock);
909 if (del_timer(&ct->timeout)) {
910 ct->timeout.function((unsigned long)ct);
915 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
917 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
919 #include <linux/netfilter/nfnetlink.h>
920 #include <linux/netfilter/nfnetlink_conntrack.h>
921 #include <linux/mutex.h>
923 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
924 * in ip_conntrack_core, since we don't want the protocols to autoload
925 * or depend on ctnetlink */
926 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
927 const struct nf_conntrack_tuple *tuple)
929 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
930 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
936 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
938 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
939 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
940 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
942 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
944 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
945 struct nf_conntrack_tuple *t)
947 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
950 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
951 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
955 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
957 int nf_ct_port_nlattr_tuple_size(void)
959 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
961 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
964 /* Used by ipt_REJECT and ip6t_REJECT. */
965 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
968 enum ip_conntrack_info ctinfo;
970 /* This ICMP is in reverse direction to the packet which caused it */
971 ct = nf_ct_get(skb, &ctinfo);
972 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
973 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
975 ctinfo = IP_CT_RELATED;
977 /* Attach to new skbuff, and increment count */
978 nskb->nfct = &ct->ct_general;
979 nskb->nfctinfo = ctinfo;
980 nf_conntrack_get(nskb->nfct);
983 /* Bring out ya dead! */
984 static struct nf_conn *
985 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
986 void *data, unsigned int *bucket)
988 struct nf_conntrack_tuple_hash *h;
990 struct hlist_nulls_node *n;
992 spin_lock_bh(&nf_conntrack_lock);
993 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
994 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
995 ct = nf_ct_tuplehash_to_ctrack(h);
1000 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1001 ct = nf_ct_tuplehash_to_ctrack(h);
1003 set_bit(IPS_DYING_BIT, &ct->status);
1005 spin_unlock_bh(&nf_conntrack_lock);
1008 atomic_inc(&ct->ct_general.use);
1009 spin_unlock_bh(&nf_conntrack_lock);
1013 void nf_ct_iterate_cleanup(struct net *net,
1014 int (*iter)(struct nf_conn *i, void *data),
1018 unsigned int bucket = 0;
1020 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1021 /* Time to push up daises... */
1022 if (del_timer(&ct->timeout))
1023 death_by_timeout((unsigned long)ct);
1024 /* ... else the timer will get him soon. */
1029 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1031 struct __nf_ct_flush_report {
1036 static int kill_report(struct nf_conn *i, void *data)
1038 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1040 /* If we fail to deliver the event, death_by_timeout() will retry */
1041 if (nf_conntrack_event_report(IPCT_DESTROY, i,
1042 fr->pid, fr->report) < 0)
1045 /* Avoid the delivery of the destroy event in death_by_timeout(). */
1046 set_bit(IPS_DYING_BIT, &i->status);
1050 static int kill_all(struct nf_conn *i, void *data)
1055 void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size)
1060 free_pages((unsigned long)hash,
1061 get_order(sizeof(struct hlist_head) * size));
1063 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1065 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1067 struct __nf_ct_flush_report fr = {
1071 nf_ct_iterate_cleanup(net, kill_report, &fr);
1073 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1075 static void nf_ct_release_dying_list(void)
1077 struct nf_conntrack_tuple_hash *h;
1079 struct hlist_nulls_node *n;
1081 spin_lock_bh(&nf_conntrack_lock);
1082 hlist_nulls_for_each_entry(h, n, &init_net.ct.dying, hnnode) {
1083 ct = nf_ct_tuplehash_to_ctrack(h);
1084 /* never fails to remove them, no listeners at this point */
1087 spin_unlock_bh(&nf_conntrack_lock);
1090 static void nf_conntrack_cleanup_init_net(void)
1092 nf_conntrack_helper_fini();
1093 nf_conntrack_proto_fini();
1094 kmem_cache_destroy(nf_conntrack_cachep);
1097 static void nf_conntrack_cleanup_net(struct net *net)
1100 nf_ct_iterate_cleanup(net, kill_all, NULL);
1101 nf_ct_release_dying_list();
1102 if (atomic_read(&net->ct.count) != 0) {
1104 goto i_see_dead_people;
1106 /* wait until all references to nf_conntrack_untracked are dropped */
1107 while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1110 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1111 nf_conntrack_htable_size);
1112 nf_conntrack_ecache_fini(net);
1113 nf_conntrack_acct_fini(net);
1114 nf_conntrack_expect_fini(net);
1115 free_percpu(net->ct.stat);
1118 /* Mishearing the voices in his head, our hero wonders how he's
1119 supposed to kill the mall. */
1120 void nf_conntrack_cleanup(struct net *net)
1122 if (net_eq(net, &init_net))
1123 rcu_assign_pointer(ip_ct_attach, NULL);
1125 /* This makes sure all current packets have passed through
1126 netfilter framework. Roll on, two-stage module
1130 nf_conntrack_cleanup_net(net);
1132 if (net_eq(net, &init_net)) {
1133 rcu_assign_pointer(nf_ct_destroy, NULL);
1134 nf_conntrack_cleanup_init_net();
1138 void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls)
1140 struct hlist_nulls_head *hash;
1141 unsigned int nr_slots, i;
1146 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1147 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1148 sz = nr_slots * sizeof(struct hlist_nulls_head);
1149 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1153 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1154 hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
1158 for (i = 0; i < nr_slots; i++)
1159 INIT_HLIST_NULLS_HEAD(&hash[i], i);
1163 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1165 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1167 int i, bucket, vmalloced, old_vmalloced;
1168 unsigned int hashsize, old_size;
1170 struct hlist_nulls_head *hash, *old_hash;
1171 struct nf_conntrack_tuple_hash *h;
1173 /* On boot, we can set this without any fancy locking. */
1174 if (!nf_conntrack_htable_size)
1175 return param_set_uint(val, kp);
1177 hashsize = simple_strtoul(val, NULL, 0);
1181 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1);
1185 /* We have to rehahs for the new table anyway, so we also can
1186 * use a newrandom seed */
1187 get_random_bytes(&rnd, sizeof(rnd));
1189 /* Lookups in the old hash might happen in parallel, which means we
1190 * might get false negatives during connection lookup. New connections
1191 * created because of a false negative won't make it into the hash
1192 * though since that required taking the lock.
1194 spin_lock_bh(&nf_conntrack_lock);
1195 for (i = 0; i < nf_conntrack_htable_size; i++) {
1196 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1197 h = hlist_nulls_entry(init_net.ct.hash[i].first,
1198 struct nf_conntrack_tuple_hash, hnnode);
1199 hlist_nulls_del_rcu(&h->hnnode);
1200 bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1201 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1204 old_size = nf_conntrack_htable_size;
1205 old_vmalloced = init_net.ct.hash_vmalloc;
1206 old_hash = init_net.ct.hash;
1208 nf_conntrack_htable_size = hashsize;
1209 init_net.ct.hash_vmalloc = vmalloced;
1210 init_net.ct.hash = hash;
1211 nf_conntrack_hash_rnd = rnd;
1212 spin_unlock_bh(&nf_conntrack_lock);
1214 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1217 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1219 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1220 &nf_conntrack_htable_size, 0600);
1222 static int nf_conntrack_init_init_net(void)
1227 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1228 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1229 if (!nf_conntrack_htable_size) {
1230 nf_conntrack_htable_size
1231 = (((num_physpages << PAGE_SHIFT) / 16384)
1232 / sizeof(struct hlist_head));
1233 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1234 nf_conntrack_htable_size = 16384;
1235 if (nf_conntrack_htable_size < 32)
1236 nf_conntrack_htable_size = 32;
1238 /* Use a max. factor of four by default to get the same max as
1239 * with the old struct list_heads. When a table size is given
1240 * we use the old value of 8 to avoid reducing the max.
1244 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1246 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1247 NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1250 nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1251 sizeof(struct nf_conn),
1252 0, SLAB_DESTROY_BY_RCU, NULL);
1253 if (!nf_conntrack_cachep) {
1254 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1259 ret = nf_conntrack_proto_init();
1263 ret = nf_conntrack_helper_init();
1270 nf_conntrack_proto_fini();
1272 kmem_cache_destroy(nf_conntrack_cachep);
1278 * We need to use special "null" values, not used in hash table
1280 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0)
1281 #define DYING_NULLS_VAL ((1<<30)+1)
1283 static int nf_conntrack_init_net(struct net *net)
1287 atomic_set(&net->ct.count, 0);
1288 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1289 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1290 net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1291 if (!net->ct.stat) {
1295 net->ct.hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1296 &net->ct.hash_vmalloc, 1);
1297 if (!net->ct.hash) {
1299 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1302 ret = nf_conntrack_expect_init(net);
1305 ret = nf_conntrack_acct_init(net);
1308 ret = nf_conntrack_ecache_init(net);
1312 /* Set up fake conntrack:
1313 - to never be deleted, not in any hashes */
1314 #ifdef CONFIG_NET_NS
1315 nf_conntrack_untracked.ct_net = &init_net;
1317 atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1318 /* - and look it like as a confirmed connection */
1319 set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1324 nf_conntrack_acct_fini(net);
1326 nf_conntrack_expect_fini(net);
1328 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1329 nf_conntrack_htable_size);
1331 free_percpu(net->ct.stat);
1336 int nf_conntrack_init(struct net *net)
1340 if (net_eq(net, &init_net)) {
1341 ret = nf_conntrack_init_init_net();
1345 ret = nf_conntrack_init_net(net);
1349 if (net_eq(net, &init_net)) {
1350 /* For use by REJECT target */
1351 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1352 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1357 if (net_eq(net, &init_net))
1358 nf_conntrack_cleanup_init_net();