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>
40 #include <net/netfilter/nf_conntrack_acct.h>
42 #define NF_CONNTRACK_VERSION "0.5.0"
44 DEFINE_SPINLOCK(nf_conntrack_lock);
45 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
47 /* nf_conntrack_standalone needs this */
48 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
49 EXPORT_SYMBOL_GPL(nf_conntrack_count);
51 unsigned int nf_conntrack_htable_size __read_mostly;
52 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
54 int nf_conntrack_max __read_mostly;
55 EXPORT_SYMBOL_GPL(nf_conntrack_max);
57 struct hlist_head *nf_conntrack_hash __read_mostly;
58 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
60 struct nf_conn nf_conntrack_untracked __read_mostly;
61 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
63 unsigned int nf_ct_log_invalid __read_mostly;
64 HLIST_HEAD(unconfirmed);
65 static int nf_conntrack_vmalloc __read_mostly;
66 static struct kmem_cache *nf_conntrack_cachep __read_mostly;
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)
80 /* The direction must be ignored, so we hash everything up to the
81 * destination ports (which is a multiple of 4) and treat the last
82 * three bytes manually.
84 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
85 h = jhash2((u32 *)tuple, n,
86 rnd ^ (((__force __u16)tuple->dst.u.all << 16) |
87 tuple->dst.protonum));
89 return ((u64)h * size) >> 32;
92 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
94 return __hash_conntrack(tuple, nf_conntrack_htable_size,
95 nf_conntrack_hash_rnd);
99 nf_ct_get_tuple(const struct sk_buff *skb,
101 unsigned int dataoff,
104 struct nf_conntrack_tuple *tuple,
105 const struct nf_conntrack_l3proto *l3proto,
106 const struct nf_conntrack_l4proto *l4proto)
108 memset(tuple, 0, sizeof(*tuple));
110 tuple->src.l3num = l3num;
111 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
114 tuple->dst.protonum = protonum;
115 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
117 return l4proto->pkt_to_tuple(skb, dataoff, tuple);
119 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
121 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
122 u_int16_t l3num, struct nf_conntrack_tuple *tuple)
124 struct nf_conntrack_l3proto *l3proto;
125 struct nf_conntrack_l4proto *l4proto;
126 unsigned int protoff;
132 l3proto = __nf_ct_l3proto_find(l3num);
133 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
134 if (ret != NF_ACCEPT) {
139 l4proto = __nf_ct_l4proto_find(l3num, protonum);
141 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
147 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
150 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
151 const struct nf_conntrack_tuple *orig,
152 const struct nf_conntrack_l3proto *l3proto,
153 const struct nf_conntrack_l4proto *l4proto)
155 memset(inverse, 0, sizeof(*inverse));
157 inverse->src.l3num = orig->src.l3num;
158 if (l3proto->invert_tuple(inverse, orig) == 0)
161 inverse->dst.dir = !orig->dst.dir;
163 inverse->dst.protonum = orig->dst.protonum;
164 return l4proto->invert_tuple(inverse, orig);
166 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
169 clean_from_lists(struct nf_conn *ct)
171 pr_debug("clean_from_lists(%p)\n", ct);
172 hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
173 hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode);
175 /* Destroy all pending expectations */
176 nf_ct_remove_expectations(ct);
180 destroy_conntrack(struct nf_conntrack *nfct)
182 struct nf_conn *ct = (struct nf_conn *)nfct;
183 struct nf_conntrack_l4proto *l4proto;
185 pr_debug("destroy_conntrack(%p)\n", ct);
186 NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
187 NF_CT_ASSERT(!timer_pending(&ct->timeout));
189 nf_conntrack_event(IPCT_DESTROY, ct);
190 set_bit(IPS_DYING_BIT, &ct->status);
192 /* To make sure we don't get any weird locking issues here:
193 * destroy_conntrack() MUST NOT be called with a write lock
194 * to nf_conntrack_lock!!! -HW */
196 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
197 if (l4proto && l4proto->destroy)
198 l4proto->destroy(ct);
202 spin_lock_bh(&nf_conntrack_lock);
203 /* Expectations will have been removed in clean_from_lists,
204 * except TFTP can create an expectation on the first packet,
205 * before connection is in the list, so we need to clean here,
207 nf_ct_remove_expectations(ct);
209 /* We overload first tuple to link into unconfirmed list. */
210 if (!nf_ct_is_confirmed(ct)) {
211 BUG_ON(hlist_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode));
212 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
215 NF_CT_STAT_INC(delete);
216 spin_unlock_bh(&nf_conntrack_lock);
219 nf_ct_put(ct->master);
221 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
222 nf_conntrack_free(ct);
225 static void death_by_timeout(unsigned long ul_conntrack)
227 struct nf_conn *ct = (void *)ul_conntrack;
228 struct nf_conn_help *help = nfct_help(ct);
229 struct nf_conntrack_helper *helper;
233 helper = rcu_dereference(help->helper);
234 if (helper && helper->destroy)
239 spin_lock_bh(&nf_conntrack_lock);
240 /* Inside lock so preempt is disabled on module removal path.
241 * Otherwise we can get spurious warnings. */
242 NF_CT_STAT_INC(delete_list);
243 clean_from_lists(ct);
244 spin_unlock_bh(&nf_conntrack_lock);
248 struct nf_conntrack_tuple_hash *
249 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple)
251 struct nf_conntrack_tuple_hash *h;
252 struct hlist_node *n;
253 unsigned int hash = hash_conntrack(tuple);
255 /* Disable BHs the entire time since we normally need to disable them
256 * at least once for the stats anyway.
259 hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash], hnode) {
260 if (nf_ct_tuple_equal(tuple, &h->tuple)) {
261 NF_CT_STAT_INC(found);
265 NF_CT_STAT_INC(searched);
271 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
273 /* Find a connection corresponding to a tuple. */
274 struct nf_conntrack_tuple_hash *
275 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple)
277 struct nf_conntrack_tuple_hash *h;
281 h = __nf_conntrack_find(tuple);
283 ct = nf_ct_tuplehash_to_ctrack(h);
284 if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
291 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
293 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
295 unsigned int repl_hash)
297 hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
298 &nf_conntrack_hash[hash]);
299 hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode,
300 &nf_conntrack_hash[repl_hash]);
303 void nf_conntrack_hash_insert(struct nf_conn *ct)
305 unsigned int hash, repl_hash;
307 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
308 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
310 spin_lock_bh(&nf_conntrack_lock);
311 __nf_conntrack_hash_insert(ct, hash, repl_hash);
312 spin_unlock_bh(&nf_conntrack_lock);
314 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
316 /* Confirm a connection given skb; places it in hash table */
318 __nf_conntrack_confirm(struct sk_buff *skb)
320 unsigned int hash, repl_hash;
321 struct nf_conntrack_tuple_hash *h;
323 struct nf_conn_help *help;
324 struct hlist_node *n;
325 enum ip_conntrack_info ctinfo;
327 ct = nf_ct_get(skb, &ctinfo);
329 /* ipt_REJECT uses nf_conntrack_attach to attach related
330 ICMP/TCP RST packets in other direction. Actual packet
331 which created connection will be IP_CT_NEW or for an
332 expected connection, IP_CT_RELATED. */
333 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
336 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
337 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
339 /* We're not in hash table, and we refuse to set up related
340 connections for unconfirmed conns. But packet copies and
341 REJECT will give spurious warnings here. */
342 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
344 /* No external references means noone else could have
346 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
347 pr_debug("Confirming conntrack %p\n", ct);
349 spin_lock_bh(&nf_conntrack_lock);
351 /* See if there's one in the list already, including reverse:
352 NAT could have grabbed it without realizing, since we're
353 not in the hash. If there is, we lost race. */
354 hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode)
355 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
358 hlist_for_each_entry(h, n, &nf_conntrack_hash[repl_hash], hnode)
359 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
363 /* Remove from unconfirmed list */
364 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
366 __nf_conntrack_hash_insert(ct, hash, repl_hash);
367 /* Timer relative to confirmation time, not original
368 setting time, otherwise we'd get timer wrap in
369 weird delay cases. */
370 ct->timeout.expires += jiffies;
371 add_timer(&ct->timeout);
372 atomic_inc(&ct->ct_general.use);
373 set_bit(IPS_CONFIRMED_BIT, &ct->status);
374 NF_CT_STAT_INC(insert);
375 spin_unlock_bh(&nf_conntrack_lock);
376 help = nfct_help(ct);
377 if (help && help->helper)
378 nf_conntrack_event_cache(IPCT_HELPER, skb);
379 #ifdef CONFIG_NF_NAT_NEEDED
380 if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
381 test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
382 nf_conntrack_event_cache(IPCT_NATINFO, skb);
384 nf_conntrack_event_cache(master_ct(ct) ?
385 IPCT_RELATED : IPCT_NEW, skb);
389 NF_CT_STAT_INC(insert_failed);
390 spin_unlock_bh(&nf_conntrack_lock);
393 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
395 /* Returns true if a connection correspondings to the tuple (required
398 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
399 const struct nf_conn *ignored_conntrack)
401 struct nf_conntrack_tuple_hash *h;
402 struct hlist_node *n;
403 unsigned int hash = hash_conntrack(tuple);
405 /* Disable BHs the entire time since we need to disable them at
406 * least once for the stats anyway.
409 hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash], hnode) {
410 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
411 nf_ct_tuple_equal(tuple, &h->tuple)) {
412 NF_CT_STAT_INC(found);
413 rcu_read_unlock_bh();
416 NF_CT_STAT_INC(searched);
418 rcu_read_unlock_bh();
422 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
424 #define NF_CT_EVICTION_RANGE 8
426 /* There's a small race here where we may free a just-assured
427 connection. Too bad: we're in trouble anyway. */
428 static noinline int early_drop(unsigned int hash)
430 /* Use oldest entry, which is roughly LRU */
431 struct nf_conntrack_tuple_hash *h;
432 struct nf_conn *ct = NULL, *tmp;
433 struct hlist_node *n;
434 unsigned int i, cnt = 0;
438 for (i = 0; i < nf_conntrack_htable_size; i++) {
439 hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash],
441 tmp = nf_ct_tuplehash_to_ctrack(h);
442 if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
447 if (ct && unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
449 if (ct || cnt >= NF_CT_EVICTION_RANGE)
451 hash = (hash + 1) % nf_conntrack_htable_size;
458 if (del_timer(&ct->timeout)) {
459 death_by_timeout((unsigned long)ct);
461 NF_CT_STAT_INC_ATOMIC(early_drop);
467 struct nf_conn *nf_conntrack_alloc(struct net *net,
468 const struct nf_conntrack_tuple *orig,
469 const struct nf_conntrack_tuple *repl,
472 struct nf_conn *ct = NULL;
474 if (unlikely(!nf_conntrack_hash_rnd_initted)) {
475 get_random_bytes(&nf_conntrack_hash_rnd, 4);
476 nf_conntrack_hash_rnd_initted = 1;
479 /* We don't want any race condition at early drop stage */
480 atomic_inc(&nf_conntrack_count);
482 if (nf_conntrack_max &&
483 unlikely(atomic_read(&nf_conntrack_count) > nf_conntrack_max)) {
484 unsigned int hash = hash_conntrack(orig);
485 if (!early_drop(hash)) {
486 atomic_dec(&nf_conntrack_count);
489 "nf_conntrack: table full, dropping"
491 return ERR_PTR(-ENOMEM);
495 ct = kmem_cache_zalloc(nf_conntrack_cachep, gfp);
497 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
498 atomic_dec(&nf_conntrack_count);
499 return ERR_PTR(-ENOMEM);
502 atomic_set(&ct->ct_general.use, 1);
503 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
504 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
505 /* Don't set timer yet: wait for confirmation */
506 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
510 INIT_RCU_HEAD(&ct->rcu);
514 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
516 static void nf_conntrack_free_rcu(struct rcu_head *head)
518 struct nf_conn *ct = container_of(head, struct nf_conn, rcu);
521 kmem_cache_free(nf_conntrack_cachep, ct);
522 atomic_dec(&nf_conntrack_count);
525 void nf_conntrack_free(struct nf_conn *ct)
527 nf_ct_ext_destroy(ct);
528 call_rcu(&ct->rcu, nf_conntrack_free_rcu);
530 EXPORT_SYMBOL_GPL(nf_conntrack_free);
532 /* Allocate a new conntrack: we return -ENOMEM if classification
533 failed due to stress. Otherwise it really is unclassifiable. */
534 static struct nf_conntrack_tuple_hash *
535 init_conntrack(struct net *net,
536 const struct nf_conntrack_tuple *tuple,
537 struct nf_conntrack_l3proto *l3proto,
538 struct nf_conntrack_l4proto *l4proto,
540 unsigned int dataoff)
543 struct nf_conn_help *help;
544 struct nf_conntrack_tuple repl_tuple;
545 struct nf_conntrack_expect *exp;
547 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
548 pr_debug("Can't invert tuple.\n");
552 ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC);
553 if (ct == NULL || IS_ERR(ct)) {
554 pr_debug("Can't allocate conntrack.\n");
555 return (struct nf_conntrack_tuple_hash *)ct;
558 if (!l4proto->new(ct, skb, dataoff)) {
559 nf_conntrack_free(ct);
560 pr_debug("init conntrack: can't track with proto module\n");
564 nf_ct_acct_ext_add(ct, GFP_ATOMIC);
566 spin_lock_bh(&nf_conntrack_lock);
567 exp = nf_ct_find_expectation(tuple);
569 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
571 /* Welcome, Mr. Bond. We've been expecting you... */
572 __set_bit(IPS_EXPECTED_BIT, &ct->status);
573 ct->master = exp->master;
575 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
577 rcu_assign_pointer(help->helper, exp->helper);
580 #ifdef CONFIG_NF_CONNTRACK_MARK
581 ct->mark = exp->master->mark;
583 #ifdef CONFIG_NF_CONNTRACK_SECMARK
584 ct->secmark = exp->master->secmark;
586 nf_conntrack_get(&ct->master->ct_general);
587 NF_CT_STAT_INC(expect_new);
589 struct nf_conntrack_helper *helper;
591 helper = __nf_ct_helper_find(&repl_tuple);
593 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
595 rcu_assign_pointer(help->helper, helper);
600 /* Overload tuple linked list to put us in unconfirmed list. */
601 hlist_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode, &unconfirmed);
603 spin_unlock_bh(&nf_conntrack_lock);
607 exp->expectfn(ct, exp);
608 nf_ct_expect_put(exp);
611 return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
614 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
615 static inline struct nf_conn *
616 resolve_normal_ct(struct sk_buff *skb,
617 unsigned int dataoff,
620 struct nf_conntrack_l3proto *l3proto,
621 struct nf_conntrack_l4proto *l4proto,
623 enum ip_conntrack_info *ctinfo)
625 struct nf_conntrack_tuple tuple;
626 struct nf_conntrack_tuple_hash *h;
629 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
630 dataoff, l3num, protonum, &tuple, l3proto,
632 pr_debug("resolve_normal_ct: Can't get tuple\n");
636 /* look for tuple match */
637 h = nf_conntrack_find_get(&tuple);
639 h = init_conntrack(&init_net, &tuple, l3proto, l4proto, skb,
646 ct = nf_ct_tuplehash_to_ctrack(h);
648 /* It exists; we have (non-exclusive) reference. */
649 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
650 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
651 /* Please set reply bit if this packet OK */
654 /* Once we've had two way comms, always ESTABLISHED. */
655 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
656 pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
657 *ctinfo = IP_CT_ESTABLISHED;
658 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
659 pr_debug("nf_conntrack_in: related packet for %p\n",
661 *ctinfo = IP_CT_RELATED;
663 pr_debug("nf_conntrack_in: new packet for %p\n", ct);
668 skb->nfct = &ct->ct_general;
669 skb->nfctinfo = *ctinfo;
674 nf_conntrack_in(u_int8_t pf, unsigned int hooknum, struct sk_buff *skb)
677 enum ip_conntrack_info ctinfo;
678 struct nf_conntrack_l3proto *l3proto;
679 struct nf_conntrack_l4proto *l4proto;
680 unsigned int dataoff;
685 /* Previously seen (loopback or untracked)? Ignore. */
687 NF_CT_STAT_INC_ATOMIC(ignore);
691 /* rcu_read_lock()ed by nf_hook_slow */
692 l3proto = __nf_ct_l3proto_find(pf);
693 ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
694 &dataoff, &protonum);
696 pr_debug("not prepared to track yet or error occured\n");
697 NF_CT_STAT_INC_ATOMIC(error);
698 NF_CT_STAT_INC_ATOMIC(invalid);
702 l4proto = __nf_ct_l4proto_find(pf, protonum);
704 /* It may be an special packet, error, unclean...
705 * inverse of the return code tells to the netfilter
706 * core what to do with the packet. */
707 if (l4proto->error != NULL &&
708 (ret = l4proto->error(skb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
709 NF_CT_STAT_INC_ATOMIC(error);
710 NF_CT_STAT_INC_ATOMIC(invalid);
714 ct = resolve_normal_ct(skb, dataoff, pf, protonum, l3proto, l4proto,
715 &set_reply, &ctinfo);
717 /* Not valid part of a connection */
718 NF_CT_STAT_INC_ATOMIC(invalid);
723 /* Too stressed to deal. */
724 NF_CT_STAT_INC_ATOMIC(drop);
728 NF_CT_ASSERT(skb->nfct);
730 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
732 /* Invalid: inverse of the return code tells
733 * the netfilter core what to do */
734 pr_debug("nf_conntrack_in: Can't track with proto module\n");
735 nf_conntrack_put(skb->nfct);
737 NF_CT_STAT_INC_ATOMIC(invalid);
741 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
742 nf_conntrack_event_cache(IPCT_STATUS, skb);
746 EXPORT_SYMBOL_GPL(nf_conntrack_in);
748 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
749 const struct nf_conntrack_tuple *orig)
754 ret = nf_ct_invert_tuple(inverse, orig,
755 __nf_ct_l3proto_find(orig->src.l3num),
756 __nf_ct_l4proto_find(orig->src.l3num,
757 orig->dst.protonum));
761 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
763 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
764 implicitly racy: see __nf_conntrack_confirm */
765 void nf_conntrack_alter_reply(struct nf_conn *ct,
766 const struct nf_conntrack_tuple *newreply)
768 struct nf_conn_help *help = nfct_help(ct);
769 struct nf_conntrack_helper *helper;
771 /* Should be unconfirmed, so not in hash table yet */
772 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
774 pr_debug("Altering reply tuple of %p to ", ct);
775 nf_ct_dump_tuple(newreply);
777 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
778 if (ct->master || (help && !hlist_empty(&help->expectations)))
782 helper = __nf_ct_helper_find(newreply);
783 if (helper == NULL) {
785 rcu_assign_pointer(help->helper, NULL);
790 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
794 memset(&help->help, 0, sizeof(help->help));
797 rcu_assign_pointer(help->helper, helper);
801 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
803 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
804 void __nf_ct_refresh_acct(struct nf_conn *ct,
805 enum ip_conntrack_info ctinfo,
806 const struct sk_buff *skb,
807 unsigned long extra_jiffies,
812 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
815 spin_lock_bh(&nf_conntrack_lock);
817 /* Only update if this is not a fixed timeout */
818 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
821 /* If not in hash table, timer will not be active yet */
822 if (!nf_ct_is_confirmed(ct)) {
823 ct->timeout.expires = extra_jiffies;
824 event = IPCT_REFRESH;
826 unsigned long newtime = jiffies + extra_jiffies;
828 /* Only update the timeout if the new timeout is at least
829 HZ jiffies from the old timeout. Need del_timer for race
830 avoidance (may already be dying). */
831 if (newtime - ct->timeout.expires >= HZ
832 && del_timer(&ct->timeout)) {
833 ct->timeout.expires = newtime;
834 add_timer(&ct->timeout);
835 event = IPCT_REFRESH;
841 struct nf_conn_counter *acct;
843 acct = nf_conn_acct_find(ct);
845 acct[CTINFO2DIR(ctinfo)].packets++;
846 acct[CTINFO2DIR(ctinfo)].bytes +=
847 skb->len - skb_network_offset(skb);
851 spin_unlock_bh(&nf_conntrack_lock);
853 /* must be unlocked when calling event cache */
855 nf_conntrack_event_cache(event, skb);
857 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
859 bool __nf_ct_kill_acct(struct nf_conn *ct,
860 enum ip_conntrack_info ctinfo,
861 const struct sk_buff *skb,
865 struct nf_conn_counter *acct;
867 spin_lock_bh(&nf_conntrack_lock);
868 acct = nf_conn_acct_find(ct);
870 acct[CTINFO2DIR(ctinfo)].packets++;
871 acct[CTINFO2DIR(ctinfo)].bytes +=
872 skb->len - skb_network_offset(skb);
874 spin_unlock_bh(&nf_conntrack_lock);
877 if (del_timer(&ct->timeout)) {
878 ct->timeout.function((unsigned long)ct);
883 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
885 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
887 #include <linux/netfilter/nfnetlink.h>
888 #include <linux/netfilter/nfnetlink_conntrack.h>
889 #include <linux/mutex.h>
891 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
892 * in ip_conntrack_core, since we don't want the protocols to autoload
893 * or depend on ctnetlink */
894 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
895 const struct nf_conntrack_tuple *tuple)
897 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
898 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
904 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
906 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
907 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
908 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
910 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
912 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
913 struct nf_conntrack_tuple *t)
915 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
918 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
919 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
923 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
926 /* Used by ipt_REJECT and ip6t_REJECT. */
927 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
930 enum ip_conntrack_info ctinfo;
932 /* This ICMP is in reverse direction to the packet which caused it */
933 ct = nf_ct_get(skb, &ctinfo);
934 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
935 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
937 ctinfo = IP_CT_RELATED;
939 /* Attach to new skbuff, and increment count */
940 nskb->nfct = &ct->ct_general;
941 nskb->nfctinfo = ctinfo;
942 nf_conntrack_get(nskb->nfct);
945 /* Bring out ya dead! */
946 static struct nf_conn *
947 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
948 void *data, unsigned int *bucket)
950 struct nf_conntrack_tuple_hash *h;
952 struct hlist_node *n;
954 spin_lock_bh(&nf_conntrack_lock);
955 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
956 hlist_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnode) {
957 ct = nf_ct_tuplehash_to_ctrack(h);
962 hlist_for_each_entry(h, n, &unconfirmed, hnode) {
963 ct = nf_ct_tuplehash_to_ctrack(h);
965 set_bit(IPS_DYING_BIT, &ct->status);
967 spin_unlock_bh(&nf_conntrack_lock);
970 atomic_inc(&ct->ct_general.use);
971 spin_unlock_bh(&nf_conntrack_lock);
976 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
979 unsigned int bucket = 0;
981 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
982 /* Time to push up daises... */
983 if (del_timer(&ct->timeout))
984 death_by_timeout((unsigned long)ct);
985 /* ... else the timer will get him soon. */
990 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
992 static int kill_all(struct nf_conn *i, void *data)
997 void nf_ct_free_hashtable(struct hlist_head *hash, int vmalloced, unsigned int size)
1002 free_pages((unsigned long)hash,
1003 get_order(sizeof(struct hlist_head) * size));
1005 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1007 void nf_conntrack_flush(void)
1009 nf_ct_iterate_cleanup(kill_all, NULL);
1011 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1013 /* Mishearing the voices in his head, our hero wonders how he's
1014 supposed to kill the mall. */
1015 void nf_conntrack_cleanup(struct net *net)
1017 rcu_assign_pointer(ip_ct_attach, NULL);
1019 /* This makes sure all current packets have passed through
1020 netfilter framework. Roll on, two-stage module
1024 nf_ct_event_cache_flush();
1026 nf_conntrack_flush();
1027 if (atomic_read(&nf_conntrack_count) != 0) {
1029 goto i_see_dead_people;
1031 /* wait until all references to nf_conntrack_untracked are dropped */
1032 while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1035 rcu_assign_pointer(nf_ct_destroy, NULL);
1037 kmem_cache_destroy(nf_conntrack_cachep);
1038 nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
1039 nf_conntrack_htable_size);
1041 nf_conntrack_acct_fini();
1042 nf_conntrack_expect_fini();
1043 nf_conntrack_helper_fini();
1044 nf_conntrack_proto_fini();
1047 struct hlist_head *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced)
1049 struct hlist_head *hash;
1050 unsigned int size, i;
1054 size = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_head));
1055 hash = (void*)__get_free_pages(GFP_KERNEL|__GFP_NOWARN,
1056 get_order(sizeof(struct hlist_head)
1060 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1061 hash = vmalloc(sizeof(struct hlist_head) * size);
1065 for (i = 0; i < size; i++)
1066 INIT_HLIST_HEAD(&hash[i]);
1070 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1072 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1074 int i, bucket, vmalloced, old_vmalloced;
1075 unsigned int hashsize, old_size;
1077 struct hlist_head *hash, *old_hash;
1078 struct nf_conntrack_tuple_hash *h;
1080 /* On boot, we can set this without any fancy locking. */
1081 if (!nf_conntrack_htable_size)
1082 return param_set_uint(val, kp);
1084 hashsize = simple_strtoul(val, NULL, 0);
1088 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced);
1092 /* We have to rehahs for the new table anyway, so we also can
1093 * use a newrandom seed */
1094 get_random_bytes(&rnd, 4);
1096 /* Lookups in the old hash might happen in parallel, which means we
1097 * might get false negatives during connection lookup. New connections
1098 * created because of a false negative won't make it into the hash
1099 * though since that required taking the lock.
1101 spin_lock_bh(&nf_conntrack_lock);
1102 for (i = 0; i < nf_conntrack_htable_size; i++) {
1103 while (!hlist_empty(&nf_conntrack_hash[i])) {
1104 h = hlist_entry(nf_conntrack_hash[i].first,
1105 struct nf_conntrack_tuple_hash, hnode);
1106 hlist_del_rcu(&h->hnode);
1107 bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1108 hlist_add_head(&h->hnode, &hash[bucket]);
1111 old_size = nf_conntrack_htable_size;
1112 old_vmalloced = nf_conntrack_vmalloc;
1113 old_hash = nf_conntrack_hash;
1115 nf_conntrack_htable_size = hashsize;
1116 nf_conntrack_vmalloc = vmalloced;
1117 nf_conntrack_hash = hash;
1118 nf_conntrack_hash_rnd = rnd;
1119 spin_unlock_bh(&nf_conntrack_lock);
1121 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1124 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1126 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1127 &nf_conntrack_htable_size, 0600);
1129 int nf_conntrack_init(struct net *net)
1134 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1135 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1136 if (!nf_conntrack_htable_size) {
1137 nf_conntrack_htable_size
1138 = (((num_physpages << PAGE_SHIFT) / 16384)
1139 / sizeof(struct hlist_head));
1140 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1141 nf_conntrack_htable_size = 16384;
1142 if (nf_conntrack_htable_size < 32)
1143 nf_conntrack_htable_size = 32;
1145 /* Use a max. factor of four by default to get the same max as
1146 * with the old struct list_heads. When a table size is given
1147 * we use the old value of 8 to avoid reducing the max.
1151 nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1152 &nf_conntrack_vmalloc);
1153 if (!nf_conntrack_hash) {
1154 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1158 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1160 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1161 NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1164 nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1165 sizeof(struct nf_conn),
1167 if (!nf_conntrack_cachep) {
1168 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1172 ret = nf_conntrack_proto_init();
1174 goto err_free_conntrack_slab;
1176 ret = nf_conntrack_expect_init();
1178 goto out_fini_proto;
1180 ret = nf_conntrack_helper_init();
1182 goto out_fini_expect;
1184 ret = nf_conntrack_acct_init();
1186 goto out_fini_helper;
1188 /* For use by REJECT target */
1189 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1190 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1192 /* Set up fake conntrack:
1193 - to never be deleted, not in any hashes */
1194 #ifdef CONFIG_NET_NS
1195 nf_conntrack_untracked.ct_net = &init_net;
1197 atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1198 /* - and look it like as a confirmed connection */
1199 set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1204 nf_conntrack_helper_fini();
1206 nf_conntrack_expect_fini();
1208 nf_conntrack_proto_fini();
1209 err_free_conntrack_slab:
1210 kmem_cache_destroy(nf_conntrack_cachep);
1212 nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
1213 nf_conntrack_htable_size);