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/sched.h>
18 #include <linux/skbuff.h>
19 #include <linux/proc_fs.h>
20 #include <linux/vmalloc.h>
21 #include <linux/stddef.h>
22 #include <linux/slab.h>
23 #include <linux/random.h>
24 #include <linux/jhash.h>
25 #include <linux/err.h>
26 #include <linux/percpu.h>
27 #include <linux/moduleparam.h>
28 #include <linux/notifier.h>
29 #include <linux/kernel.h>
30 #include <linux/netdevice.h>
31 #include <linux/socket.h>
33 #include <linux/nsproxy.h>
34 #include <linux/rculist_nulls.h>
36 #include <net/netfilter/nf_conntrack.h>
37 #include <net/netfilter/nf_conntrack_l3proto.h>
38 #include <net/netfilter/nf_conntrack_l4proto.h>
39 #include <net/netfilter/nf_conntrack_expect.h>
40 #include <net/netfilter/nf_conntrack_helper.h>
41 #include <net/netfilter/nf_conntrack_core.h>
42 #include <net/netfilter/nf_conntrack_extend.h>
43 #include <net/netfilter/nf_conntrack_acct.h>
44 #include <net/netfilter/nf_conntrack_ecache.h>
45 #include <net/netfilter/nf_nat.h>
46 #include <net/netfilter/nf_nat_core.h>
48 #define NF_CONNTRACK_VERSION "0.5.0"
50 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
51 enum nf_nat_manip_type manip,
52 const struct nlattr *attr) __read_mostly;
53 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
55 DEFINE_SPINLOCK(nf_conntrack_lock);
56 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
58 unsigned int nf_conntrack_htable_size __read_mostly;
59 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
61 unsigned int nf_conntrack_max __read_mostly;
62 EXPORT_SYMBOL_GPL(nf_conntrack_max);
64 struct nf_conn nf_conntrack_untracked __read_mostly;
65 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
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 net *net,
89 const struct nf_conntrack_tuple *tuple)
91 return __hash_conntrack(tuple, net->ct.htable_size,
92 nf_conntrack_hash_rnd);
96 nf_ct_get_tuple(const struct sk_buff *skb,
101 struct nf_conntrack_tuple *tuple,
102 const struct nf_conntrack_l3proto *l3proto,
103 const struct nf_conntrack_l4proto *l4proto)
105 memset(tuple, 0, sizeof(*tuple));
107 tuple->src.l3num = l3num;
108 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
111 tuple->dst.protonum = protonum;
112 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
114 return l4proto->pkt_to_tuple(skb, dataoff, tuple);
116 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
118 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
119 u_int16_t l3num, struct nf_conntrack_tuple *tuple)
121 struct nf_conntrack_l3proto *l3proto;
122 struct nf_conntrack_l4proto *l4proto;
123 unsigned int protoff;
129 l3proto = __nf_ct_l3proto_find(l3num);
130 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
131 if (ret != NF_ACCEPT) {
136 l4proto = __nf_ct_l4proto_find(l3num, protonum);
138 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
144 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
147 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
148 const struct nf_conntrack_tuple *orig,
149 const struct nf_conntrack_l3proto *l3proto,
150 const struct nf_conntrack_l4proto *l4proto)
152 memset(inverse, 0, sizeof(*inverse));
154 inverse->src.l3num = orig->src.l3num;
155 if (l3proto->invert_tuple(inverse, orig) == 0)
158 inverse->dst.dir = !orig->dst.dir;
160 inverse->dst.protonum = orig->dst.protonum;
161 return l4proto->invert_tuple(inverse, orig);
163 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
166 clean_from_lists(struct nf_conn *ct)
168 pr_debug("clean_from_lists(%p)\n", ct);
169 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
170 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
172 /* Destroy all pending expectations */
173 nf_ct_remove_expectations(ct);
177 destroy_conntrack(struct nf_conntrack *nfct)
179 struct nf_conn *ct = (struct nf_conn *)nfct;
180 struct net *net = nf_ct_net(ct);
181 struct nf_conntrack_l4proto *l4proto;
183 pr_debug("destroy_conntrack(%p)\n", ct);
184 NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
185 NF_CT_ASSERT(!timer_pending(&ct->timeout));
187 /* To make sure we don't get any weird locking issues here:
188 * destroy_conntrack() MUST NOT be called with a write lock
189 * to nf_conntrack_lock!!! -HW */
191 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
192 if (l4proto && l4proto->destroy)
193 l4proto->destroy(ct);
197 spin_lock_bh(&nf_conntrack_lock);
198 /* Expectations will have been removed in clean_from_lists,
199 * except TFTP can create an expectation on the first packet,
200 * before connection is in the list, so we need to clean here,
202 nf_ct_remove_expectations(ct);
204 /* We overload first tuple to link into unconfirmed list. */
205 if (!nf_ct_is_confirmed(ct)) {
206 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
207 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
210 NF_CT_STAT_INC(net, delete);
211 spin_unlock_bh(&nf_conntrack_lock);
214 nf_ct_put(ct->master);
216 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
217 nf_conntrack_free(ct);
220 void nf_ct_delete_from_lists(struct nf_conn *ct)
222 struct net *net = nf_ct_net(ct);
224 nf_ct_helper_destroy(ct);
225 spin_lock_bh(&nf_conntrack_lock);
226 /* Inside lock so preempt is disabled on module removal path.
227 * Otherwise we can get spurious warnings. */
228 NF_CT_STAT_INC(net, delete_list);
229 clean_from_lists(ct);
230 spin_unlock_bh(&nf_conntrack_lock);
232 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
234 static void death_by_event(unsigned long ul_conntrack)
236 struct nf_conn *ct = (void *)ul_conntrack;
237 struct net *net = nf_ct_net(ct);
239 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
240 /* bad luck, let's retry again */
241 ct->timeout.expires = jiffies +
242 (random32() % net->ct.sysctl_events_retry_timeout);
243 add_timer(&ct->timeout);
246 /* we've got the event delivered, now it's dying */
247 set_bit(IPS_DYING_BIT, &ct->status);
248 spin_lock(&nf_conntrack_lock);
249 hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
250 spin_unlock(&nf_conntrack_lock);
254 void nf_ct_insert_dying_list(struct nf_conn *ct)
256 struct net *net = nf_ct_net(ct);
258 /* add this conntrack to the dying list */
259 spin_lock_bh(&nf_conntrack_lock);
260 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
262 spin_unlock_bh(&nf_conntrack_lock);
263 /* set a new timer to retry event delivery */
264 setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
265 ct->timeout.expires = jiffies +
266 (random32() % net->ct.sysctl_events_retry_timeout);
267 add_timer(&ct->timeout);
269 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
271 static void death_by_timeout(unsigned long ul_conntrack)
273 struct nf_conn *ct = (void *)ul_conntrack;
275 if (!test_bit(IPS_DYING_BIT, &ct->status) &&
276 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
277 /* destroy event was not delivered */
278 nf_ct_delete_from_lists(ct);
279 nf_ct_insert_dying_list(ct);
282 set_bit(IPS_DYING_BIT, &ct->status);
283 nf_ct_delete_from_lists(ct);
289 * - Caller must take a reference on returned object
290 * and recheck nf_ct_tuple_equal(tuple, &h->tuple)
292 * - Caller must lock nf_conntrack_lock before calling this function
294 struct nf_conntrack_tuple_hash *
295 __nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple)
297 struct nf_conntrack_tuple_hash *h;
298 struct hlist_nulls_node *n;
299 unsigned int hash = hash_conntrack(net, tuple);
301 /* Disable BHs the entire time since we normally need to disable them
302 * at least once for the stats anyway.
306 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
307 if (nf_ct_tuple_equal(tuple, &h->tuple)) {
308 NF_CT_STAT_INC(net, found);
312 NF_CT_STAT_INC(net, searched);
315 * if the nulls value we got at the end of this lookup is
316 * not the expected one, we must restart lookup.
317 * We probably met an item that was moved to another chain.
319 if (get_nulls_value(n) != hash)
325 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
327 /* Find a connection corresponding to a tuple. */
328 struct nf_conntrack_tuple_hash *
329 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple)
331 struct nf_conntrack_tuple_hash *h;
336 h = __nf_conntrack_find(net, tuple);
338 ct = nf_ct_tuplehash_to_ctrack(h);
339 if (unlikely(nf_ct_is_dying(ct) ||
340 !atomic_inc_not_zero(&ct->ct_general.use)))
343 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) {
353 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
355 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
357 unsigned int repl_hash)
359 struct net *net = nf_ct_net(ct);
361 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
362 &net->ct.hash[hash]);
363 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
364 &net->ct.hash[repl_hash]);
367 void nf_conntrack_hash_insert(struct nf_conn *ct)
369 struct net *net = nf_ct_net(ct);
370 unsigned int hash, repl_hash;
372 hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
373 repl_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
375 __nf_conntrack_hash_insert(ct, hash, repl_hash);
377 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
379 /* Confirm a connection given skb; places it in hash table */
381 __nf_conntrack_confirm(struct sk_buff *skb)
383 unsigned int hash, repl_hash;
384 struct nf_conntrack_tuple_hash *h;
386 struct nf_conn_help *help;
387 struct hlist_nulls_node *n;
388 enum ip_conntrack_info ctinfo;
391 ct = nf_ct_get(skb, &ctinfo);
394 /* ipt_REJECT uses nf_conntrack_attach to attach related
395 ICMP/TCP RST packets in other direction. Actual packet
396 which created connection will be IP_CT_NEW or for an
397 expected connection, IP_CT_RELATED. */
398 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
401 hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
402 repl_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
404 /* We're not in hash table, and we refuse to set up related
405 connections for unconfirmed conns. But packet copies and
406 REJECT will give spurious warnings here. */
407 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
409 /* No external references means noone else could have
411 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
412 pr_debug("Confirming conntrack %p\n", ct);
414 spin_lock_bh(&nf_conntrack_lock);
416 /* See if there's one in the list already, including reverse:
417 NAT could have grabbed it without realizing, since we're
418 not in the hash. If there is, we lost race. */
419 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
420 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
423 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
424 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
428 /* Remove from unconfirmed list */
429 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
431 /* Timer relative to confirmation time, not original
432 setting time, otherwise we'd get timer wrap in
433 weird delay cases. */
434 ct->timeout.expires += jiffies;
435 add_timer(&ct->timeout);
436 atomic_inc(&ct->ct_general.use);
437 set_bit(IPS_CONFIRMED_BIT, &ct->status);
439 /* Since the lookup is lockless, hash insertion must be done after
440 * starting the timer and setting the CONFIRMED bit. The RCU barriers
441 * guarantee that no other CPU can find the conntrack before the above
442 * stores are visible.
444 __nf_conntrack_hash_insert(ct, hash, repl_hash);
445 NF_CT_STAT_INC(net, insert);
446 spin_unlock_bh(&nf_conntrack_lock);
448 help = nfct_help(ct);
449 if (help && help->helper)
450 nf_conntrack_event_cache(IPCT_HELPER, ct);
452 nf_conntrack_event_cache(master_ct(ct) ?
453 IPCT_RELATED : IPCT_NEW, ct);
457 NF_CT_STAT_INC(net, insert_failed);
458 spin_unlock_bh(&nf_conntrack_lock);
461 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
463 /* Returns true if a connection correspondings to the tuple (required
466 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
467 const struct nf_conn *ignored_conntrack)
469 struct net *net = nf_ct_net(ignored_conntrack);
470 struct nf_conntrack_tuple_hash *h;
471 struct hlist_nulls_node *n;
472 unsigned int hash = hash_conntrack(net, tuple);
474 /* Disable BHs the entire time since we need to disable them at
475 * least once for the stats anyway.
478 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
479 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
480 nf_ct_tuple_equal(tuple, &h->tuple)) {
481 NF_CT_STAT_INC(net, found);
482 rcu_read_unlock_bh();
485 NF_CT_STAT_INC(net, searched);
487 rcu_read_unlock_bh();
491 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
493 #define NF_CT_EVICTION_RANGE 8
495 /* There's a small race here where we may free a just-assured
496 connection. Too bad: we're in trouble anyway. */
497 static noinline int early_drop(struct net *net, unsigned int hash)
499 /* Use oldest entry, which is roughly LRU */
500 struct nf_conntrack_tuple_hash *h;
501 struct nf_conn *ct = NULL, *tmp;
502 struct hlist_nulls_node *n;
503 unsigned int i, cnt = 0;
507 for (i = 0; i < net->ct.htable_size; i++) {
508 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
510 tmp = nf_ct_tuplehash_to_ctrack(h);
511 if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
517 if (likely(!nf_ct_is_dying(ct) &&
518 atomic_inc_not_zero(&ct->ct_general.use)))
524 if (cnt >= NF_CT_EVICTION_RANGE)
527 hash = (hash + 1) % net->ct.htable_size;
534 if (del_timer(&ct->timeout)) {
535 death_by_timeout((unsigned long)ct);
537 NF_CT_STAT_INC_ATOMIC(net, early_drop);
543 struct nf_conn *nf_conntrack_alloc(struct net *net,
544 const struct nf_conntrack_tuple *orig,
545 const struct nf_conntrack_tuple *repl,
550 if (unlikely(!nf_conntrack_hash_rnd_initted)) {
551 get_random_bytes(&nf_conntrack_hash_rnd,
552 sizeof(nf_conntrack_hash_rnd));
553 nf_conntrack_hash_rnd_initted = 1;
556 /* We don't want any race condition at early drop stage */
557 atomic_inc(&net->ct.count);
559 if (nf_conntrack_max &&
560 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
561 unsigned int hash = hash_conntrack(net, orig);
562 if (!early_drop(net, hash)) {
563 atomic_dec(&net->ct.count);
566 "nf_conntrack: table full, dropping"
568 return ERR_PTR(-ENOMEM);
573 * Do not use kmem_cache_zalloc(), as this cache uses
574 * SLAB_DESTROY_BY_RCU.
576 ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
578 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
579 atomic_dec(&net->ct.count);
580 return ERR_PTR(-ENOMEM);
583 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
584 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
586 memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
587 sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
588 spin_lock_init(&ct->lock);
589 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
590 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
591 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
592 ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev = NULL;
593 /* Don't set timer yet: wait for confirmation */
594 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
600 * changes to lookup keys must be done before setting refcnt to 1
603 atomic_set(&ct->ct_general.use, 1);
606 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
608 void nf_conntrack_free(struct nf_conn *ct)
610 struct net *net = nf_ct_net(ct);
612 nf_ct_ext_destroy(ct);
613 atomic_dec(&net->ct.count);
615 kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
617 EXPORT_SYMBOL_GPL(nf_conntrack_free);
619 /* Allocate a new conntrack: we return -ENOMEM if classification
620 failed due to stress. Otherwise it really is unclassifiable. */
621 static struct nf_conntrack_tuple_hash *
622 init_conntrack(struct net *net,
623 const struct nf_conntrack_tuple *tuple,
624 struct nf_conntrack_l3proto *l3proto,
625 struct nf_conntrack_l4proto *l4proto,
627 unsigned int dataoff)
630 struct nf_conn_help *help;
631 struct nf_conntrack_tuple repl_tuple;
632 struct nf_conntrack_expect *exp;
634 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
635 pr_debug("Can't invert tuple.\n");
639 ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC);
641 pr_debug("Can't allocate conntrack.\n");
642 return (struct nf_conntrack_tuple_hash *)ct;
645 if (!l4proto->new(ct, skb, dataoff)) {
646 nf_conntrack_free(ct);
647 pr_debug("init conntrack: can't track with proto module\n");
651 nf_ct_acct_ext_add(ct, GFP_ATOMIC);
652 nf_ct_ecache_ext_add(ct, GFP_ATOMIC);
654 spin_lock_bh(&nf_conntrack_lock);
655 exp = nf_ct_find_expectation(net, tuple);
657 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
659 /* Welcome, Mr. Bond. We've been expecting you... */
660 __set_bit(IPS_EXPECTED_BIT, &ct->status);
661 ct->master = exp->master;
663 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
665 rcu_assign_pointer(help->helper, exp->helper);
668 #ifdef CONFIG_NF_CONNTRACK_MARK
669 ct->mark = exp->master->mark;
671 #ifdef CONFIG_NF_CONNTRACK_SECMARK
672 ct->secmark = exp->master->secmark;
674 nf_conntrack_get(&ct->master->ct_general);
675 NF_CT_STAT_INC(net, expect_new);
677 __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
678 NF_CT_STAT_INC(net, new);
681 /* Overload tuple linked list to put us in unconfirmed list. */
682 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
683 &net->ct.unconfirmed);
685 spin_unlock_bh(&nf_conntrack_lock);
689 exp->expectfn(ct, exp);
690 nf_ct_expect_put(exp);
693 return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
696 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
697 static inline struct nf_conn *
698 resolve_normal_ct(struct net *net,
700 unsigned int dataoff,
703 struct nf_conntrack_l3proto *l3proto,
704 struct nf_conntrack_l4proto *l4proto,
706 enum ip_conntrack_info *ctinfo)
708 struct nf_conntrack_tuple tuple;
709 struct nf_conntrack_tuple_hash *h;
712 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
713 dataoff, l3num, protonum, &tuple, l3proto,
715 pr_debug("resolve_normal_ct: Can't get tuple\n");
719 /* look for tuple match */
720 h = nf_conntrack_find_get(net, &tuple);
722 h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff);
728 ct = nf_ct_tuplehash_to_ctrack(h);
730 /* It exists; we have (non-exclusive) reference. */
731 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
732 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
733 /* Please set reply bit if this packet OK */
736 /* Once we've had two way comms, always ESTABLISHED. */
737 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
738 pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
739 *ctinfo = IP_CT_ESTABLISHED;
740 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
741 pr_debug("nf_conntrack_in: related packet for %p\n",
743 *ctinfo = IP_CT_RELATED;
745 pr_debug("nf_conntrack_in: new packet for %p\n", ct);
750 skb->nfct = &ct->ct_general;
751 skb->nfctinfo = *ctinfo;
756 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
760 enum ip_conntrack_info ctinfo;
761 struct nf_conntrack_l3proto *l3proto;
762 struct nf_conntrack_l4proto *l4proto;
763 unsigned int dataoff;
768 /* Previously seen (loopback or untracked)? Ignore. */
770 NF_CT_STAT_INC_ATOMIC(net, ignore);
774 /* rcu_read_lock()ed by nf_hook_slow */
775 l3proto = __nf_ct_l3proto_find(pf);
776 ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
777 &dataoff, &protonum);
779 pr_debug("not prepared to track yet or error occured\n");
780 NF_CT_STAT_INC_ATOMIC(net, error);
781 NF_CT_STAT_INC_ATOMIC(net, invalid);
785 l4proto = __nf_ct_l4proto_find(pf, protonum);
787 /* It may be an special packet, error, unclean...
788 * inverse of the return code tells to the netfilter
789 * core what to do with the packet. */
790 if (l4proto->error != NULL) {
791 ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum);
793 NF_CT_STAT_INC_ATOMIC(net, error);
794 NF_CT_STAT_INC_ATOMIC(net, invalid);
799 ct = resolve_normal_ct(net, skb, dataoff, pf, protonum,
800 l3proto, l4proto, &set_reply, &ctinfo);
802 /* Not valid part of a connection */
803 NF_CT_STAT_INC_ATOMIC(net, invalid);
808 /* Too stressed to deal. */
809 NF_CT_STAT_INC_ATOMIC(net, drop);
813 NF_CT_ASSERT(skb->nfct);
815 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
817 /* Invalid: inverse of the return code tells
818 * the netfilter core what to do */
819 pr_debug("nf_conntrack_in: Can't track with proto module\n");
820 nf_conntrack_put(skb->nfct);
822 NF_CT_STAT_INC_ATOMIC(net, invalid);
824 NF_CT_STAT_INC_ATOMIC(net, drop);
828 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
829 nf_conntrack_event_cache(IPCT_STATUS, ct);
833 EXPORT_SYMBOL_GPL(nf_conntrack_in);
835 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
836 const struct nf_conntrack_tuple *orig)
841 ret = nf_ct_invert_tuple(inverse, orig,
842 __nf_ct_l3proto_find(orig->src.l3num),
843 __nf_ct_l4proto_find(orig->src.l3num,
844 orig->dst.protonum));
848 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
850 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
851 implicitly racy: see __nf_conntrack_confirm */
852 void nf_conntrack_alter_reply(struct nf_conn *ct,
853 const struct nf_conntrack_tuple *newreply)
855 struct nf_conn_help *help = nfct_help(ct);
857 /* Should be unconfirmed, so not in hash table yet */
858 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
860 pr_debug("Altering reply tuple of %p to ", ct);
861 nf_ct_dump_tuple(newreply);
863 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
864 if (ct->master || (help && !hlist_empty(&help->expectations)))
868 __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
871 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
873 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
874 void __nf_ct_refresh_acct(struct nf_conn *ct,
875 enum ip_conntrack_info ctinfo,
876 const struct sk_buff *skb,
877 unsigned long extra_jiffies,
880 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
883 /* Only update if this is not a fixed timeout */
884 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
887 /* If not in hash table, timer will not be active yet */
888 if (!nf_ct_is_confirmed(ct)) {
889 ct->timeout.expires = extra_jiffies;
891 unsigned long newtime = jiffies + extra_jiffies;
893 /* Only update the timeout if the new timeout is at least
894 HZ jiffies from the old timeout. Need del_timer for race
895 avoidance (may already be dying). */
896 if (newtime - ct->timeout.expires >= HZ)
897 mod_timer_pending(&ct->timeout, newtime);
902 struct nf_conn_counter *acct;
904 acct = nf_conn_acct_find(ct);
906 spin_lock_bh(&ct->lock);
907 acct[CTINFO2DIR(ctinfo)].packets++;
908 acct[CTINFO2DIR(ctinfo)].bytes +=
909 skb->len - skb_network_offset(skb);
910 spin_unlock_bh(&ct->lock);
914 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
916 bool __nf_ct_kill_acct(struct nf_conn *ct,
917 enum ip_conntrack_info ctinfo,
918 const struct sk_buff *skb,
922 struct nf_conn_counter *acct;
924 acct = nf_conn_acct_find(ct);
926 spin_lock_bh(&ct->lock);
927 acct[CTINFO2DIR(ctinfo)].packets++;
928 acct[CTINFO2DIR(ctinfo)].bytes +=
929 skb->len - skb_network_offset(skb);
930 spin_unlock_bh(&ct->lock);
934 if (del_timer(&ct->timeout)) {
935 ct->timeout.function((unsigned long)ct);
940 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
942 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
944 #include <linux/netfilter/nfnetlink.h>
945 #include <linux/netfilter/nfnetlink_conntrack.h>
946 #include <linux/mutex.h>
948 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
949 * in ip_conntrack_core, since we don't want the protocols to autoload
950 * or depend on ctnetlink */
951 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
952 const struct nf_conntrack_tuple *tuple)
954 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
955 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
961 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
963 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
964 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
965 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
967 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
969 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
970 struct nf_conntrack_tuple *t)
972 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
975 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
976 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
980 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
982 int nf_ct_port_nlattr_tuple_size(void)
984 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
986 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
989 /* Used by ipt_REJECT and ip6t_REJECT. */
990 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
993 enum ip_conntrack_info ctinfo;
995 /* This ICMP is in reverse direction to the packet which caused it */
996 ct = nf_ct_get(skb, &ctinfo);
997 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
998 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
1000 ctinfo = IP_CT_RELATED;
1002 /* Attach to new skbuff, and increment count */
1003 nskb->nfct = &ct->ct_general;
1004 nskb->nfctinfo = ctinfo;
1005 nf_conntrack_get(nskb->nfct);
1008 /* Bring out ya dead! */
1009 static struct nf_conn *
1010 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1011 void *data, unsigned int *bucket)
1013 struct nf_conntrack_tuple_hash *h;
1015 struct hlist_nulls_node *n;
1017 spin_lock_bh(&nf_conntrack_lock);
1018 for (; *bucket < net->ct.htable_size; (*bucket)++) {
1019 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1020 ct = nf_ct_tuplehash_to_ctrack(h);
1025 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1026 ct = nf_ct_tuplehash_to_ctrack(h);
1028 set_bit(IPS_DYING_BIT, &ct->status);
1030 spin_unlock_bh(&nf_conntrack_lock);
1033 atomic_inc(&ct->ct_general.use);
1034 spin_unlock_bh(&nf_conntrack_lock);
1038 void nf_ct_iterate_cleanup(struct net *net,
1039 int (*iter)(struct nf_conn *i, void *data),
1043 unsigned int bucket = 0;
1045 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1046 /* Time to push up daises... */
1047 if (del_timer(&ct->timeout))
1048 death_by_timeout((unsigned long)ct);
1049 /* ... else the timer will get him soon. */
1054 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1056 struct __nf_ct_flush_report {
1061 static int kill_report(struct nf_conn *i, void *data)
1063 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1065 /* If we fail to deliver the event, death_by_timeout() will retry */
1066 if (nf_conntrack_event_report(IPCT_DESTROY, i,
1067 fr->pid, fr->report) < 0)
1070 /* Avoid the delivery of the destroy event in death_by_timeout(). */
1071 set_bit(IPS_DYING_BIT, &i->status);
1075 static int kill_all(struct nf_conn *i, void *data)
1080 void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size)
1085 free_pages((unsigned long)hash,
1086 get_order(sizeof(struct hlist_head) * size));
1088 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1090 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1092 struct __nf_ct_flush_report fr = {
1096 nf_ct_iterate_cleanup(net, kill_report, &fr);
1098 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1100 static void nf_ct_release_dying_list(struct net *net)
1102 struct nf_conntrack_tuple_hash *h;
1104 struct hlist_nulls_node *n;
1106 spin_lock_bh(&nf_conntrack_lock);
1107 hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) {
1108 ct = nf_ct_tuplehash_to_ctrack(h);
1109 /* never fails to remove them, no listeners at this point */
1112 spin_unlock_bh(&nf_conntrack_lock);
1115 static void nf_conntrack_cleanup_init_net(void)
1117 /* wait until all references to nf_conntrack_untracked are dropped */
1118 while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1121 nf_conntrack_helper_fini();
1122 nf_conntrack_proto_fini();
1125 static void nf_conntrack_cleanup_net(struct net *net)
1128 nf_ct_iterate_cleanup(net, kill_all, NULL);
1129 nf_ct_release_dying_list(net);
1130 if (atomic_read(&net->ct.count) != 0) {
1132 goto i_see_dead_people;
1135 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1136 net->ct.htable_size);
1137 nf_conntrack_ecache_fini(net);
1138 nf_conntrack_acct_fini(net);
1139 nf_conntrack_expect_fini(net);
1140 kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1141 kfree(net->ct.slabname);
1142 free_percpu(net->ct.stat);
1145 /* Mishearing the voices in his head, our hero wonders how he's
1146 supposed to kill the mall. */
1147 void nf_conntrack_cleanup(struct net *net)
1149 if (net_eq(net, &init_net))
1150 rcu_assign_pointer(ip_ct_attach, NULL);
1152 /* This makes sure all current packets have passed through
1153 netfilter framework. Roll on, two-stage module
1157 nf_conntrack_cleanup_net(net);
1159 if (net_eq(net, &init_net)) {
1160 rcu_assign_pointer(nf_ct_destroy, NULL);
1161 nf_conntrack_cleanup_init_net();
1165 void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls)
1167 struct hlist_nulls_head *hash;
1168 unsigned int nr_slots, i;
1173 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1174 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1175 sz = nr_slots * sizeof(struct hlist_nulls_head);
1176 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1180 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1181 hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
1185 for (i = 0; i < nr_slots; i++)
1186 INIT_HLIST_NULLS_HEAD(&hash[i], i);
1190 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1192 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1194 int i, bucket, vmalloced, old_vmalloced;
1195 unsigned int hashsize, old_size;
1196 struct hlist_nulls_head *hash, *old_hash;
1197 struct nf_conntrack_tuple_hash *h;
1199 if (current->nsproxy->net_ns != &init_net)
1202 /* On boot, we can set this without any fancy locking. */
1203 if (!nf_conntrack_htable_size)
1204 return param_set_uint(val, kp);
1206 hashsize = simple_strtoul(val, NULL, 0);
1210 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1);
1214 /* Lookups in the old hash might happen in parallel, which means we
1215 * might get false negatives during connection lookup. New connections
1216 * created because of a false negative won't make it into the hash
1217 * though since that required taking the lock.
1219 spin_lock_bh(&nf_conntrack_lock);
1220 for (i = 0; i < init_net.ct.htable_size; i++) {
1221 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1222 h = hlist_nulls_entry(init_net.ct.hash[i].first,
1223 struct nf_conntrack_tuple_hash, hnnode);
1224 hlist_nulls_del_rcu(&h->hnnode);
1225 bucket = __hash_conntrack(&h->tuple, hashsize,
1226 nf_conntrack_hash_rnd);
1227 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1230 old_size = init_net.ct.htable_size;
1231 old_vmalloced = init_net.ct.hash_vmalloc;
1232 old_hash = init_net.ct.hash;
1234 init_net.ct.htable_size = nf_conntrack_htable_size = hashsize;
1235 init_net.ct.hash_vmalloc = vmalloced;
1236 init_net.ct.hash = hash;
1237 spin_unlock_bh(&nf_conntrack_lock);
1239 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1242 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1244 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1245 &nf_conntrack_htable_size, 0600);
1247 static int nf_conntrack_init_init_net(void)
1252 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1253 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1254 if (!nf_conntrack_htable_size) {
1255 nf_conntrack_htable_size
1256 = (((totalram_pages << PAGE_SHIFT) / 16384)
1257 / sizeof(struct hlist_head));
1258 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1259 nf_conntrack_htable_size = 16384;
1260 if (nf_conntrack_htable_size < 32)
1261 nf_conntrack_htable_size = 32;
1263 /* Use a max. factor of four by default to get the same max as
1264 * with the old struct list_heads. When a table size is given
1265 * we use the old value of 8 to avoid reducing the max.
1269 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1271 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1272 NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1275 ret = nf_conntrack_proto_init();
1279 ret = nf_conntrack_helper_init();
1283 /* Set up fake conntrack: to never be deleted, not in any hashes */
1284 #ifdef CONFIG_NET_NS
1285 nf_conntrack_untracked.ct_net = &init_net;
1287 atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1288 /* - and look it like as a confirmed connection */
1289 set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1294 nf_conntrack_proto_fini();
1300 * We need to use special "null" values, not used in hash table
1302 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0)
1303 #define DYING_NULLS_VAL ((1<<30)+1)
1305 static int nf_conntrack_init_net(struct net *net)
1309 atomic_set(&net->ct.count, 0);
1310 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1311 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1312 net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1313 if (!net->ct.stat) {
1318 net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1319 if (!net->ct.slabname) {
1324 net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1325 sizeof(struct nf_conn), 0,
1326 SLAB_DESTROY_BY_RCU, NULL);
1327 if (!net->ct.nf_conntrack_cachep) {
1328 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1333 net->ct.htable_size = nf_conntrack_htable_size;
1334 net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size,
1335 &net->ct.hash_vmalloc, 1);
1336 if (!net->ct.hash) {
1338 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1341 ret = nf_conntrack_expect_init(net);
1344 ret = nf_conntrack_acct_init(net);
1347 ret = nf_conntrack_ecache_init(net);
1354 nf_conntrack_acct_fini(net);
1356 nf_conntrack_expect_fini(net);
1358 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1359 net->ct.htable_size);
1361 kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1363 kfree(net->ct.slabname);
1365 free_percpu(net->ct.stat);
1370 s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
1371 enum ip_conntrack_dir dir,
1373 EXPORT_SYMBOL_GPL(nf_ct_nat_offset);
1375 int nf_conntrack_init(struct net *net)
1379 if (net_eq(net, &init_net)) {
1380 ret = nf_conntrack_init_init_net();
1384 ret = nf_conntrack_init_net(net);
1388 if (net_eq(net, &init_net)) {
1389 /* For use by REJECT target */
1390 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1391 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1393 /* Howto get NAT offsets */
1394 rcu_assign_pointer(nf_ct_nat_offset, NULL);
1399 if (net_eq(net, &init_net))
1400 nf_conntrack_cleanup_init_net();