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>
41 #include <net/netfilter/nf_nat.h>
42 #include <net/netfilter/nf_nat_core.h>
44 #define NF_CONNTRACK_VERSION "0.5.0"
46 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
47 enum nf_nat_manip_type manip,
48 struct nlattr *attr) __read_mostly;
49 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
51 DEFINE_SPINLOCK(nf_conntrack_lock);
52 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
54 unsigned int nf_conntrack_htable_size __read_mostly;
55 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
57 int nf_conntrack_max __read_mostly;
58 EXPORT_SYMBOL_GPL(nf_conntrack_max);
60 struct nf_conn nf_conntrack_untracked __read_mostly;
61 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
63 static struct kmem_cache *nf_conntrack_cachep __read_mostly;
65 static int nf_conntrack_hash_rnd_initted;
66 static unsigned int nf_conntrack_hash_rnd;
68 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
69 unsigned int size, unsigned int rnd)
74 /* The direction must be ignored, so we hash everything up to the
75 * destination ports (which is a multiple of 4) and treat the last
76 * three bytes manually.
78 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
79 h = jhash2((u32 *)tuple, n,
80 rnd ^ (((__force __u16)tuple->dst.u.all << 16) |
81 tuple->dst.protonum));
83 return ((u64)h * size) >> 32;
86 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
88 return __hash_conntrack(tuple, nf_conntrack_htable_size,
89 nf_conntrack_hash_rnd);
93 nf_ct_get_tuple(const struct sk_buff *skb,
98 struct nf_conntrack_tuple *tuple,
99 const struct nf_conntrack_l3proto *l3proto,
100 const struct nf_conntrack_l4proto *l4proto)
102 memset(tuple, 0, sizeof(*tuple));
104 tuple->src.l3num = l3num;
105 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
108 tuple->dst.protonum = protonum;
109 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
111 return l4proto->pkt_to_tuple(skb, dataoff, tuple);
113 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
115 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
116 u_int16_t l3num, struct nf_conntrack_tuple *tuple)
118 struct nf_conntrack_l3proto *l3proto;
119 struct nf_conntrack_l4proto *l4proto;
120 unsigned int protoff;
126 l3proto = __nf_ct_l3proto_find(l3num);
127 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
128 if (ret != NF_ACCEPT) {
133 l4proto = __nf_ct_l4proto_find(l3num, protonum);
135 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
141 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
144 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
145 const struct nf_conntrack_tuple *orig,
146 const struct nf_conntrack_l3proto *l3proto,
147 const struct nf_conntrack_l4proto *l4proto)
149 memset(inverse, 0, sizeof(*inverse));
151 inverse->src.l3num = orig->src.l3num;
152 if (l3proto->invert_tuple(inverse, orig) == 0)
155 inverse->dst.dir = !orig->dst.dir;
157 inverse->dst.protonum = orig->dst.protonum;
158 return l4proto->invert_tuple(inverse, orig);
160 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
163 clean_from_lists(struct nf_conn *ct)
165 pr_debug("clean_from_lists(%p)\n", ct);
166 hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
167 hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode);
169 /* Destroy all pending expectations */
170 nf_ct_remove_expectations(ct);
174 destroy_conntrack(struct nf_conntrack *nfct)
176 struct nf_conn *ct = (struct nf_conn *)nfct;
177 struct net *net = nf_ct_net(ct);
178 struct nf_conntrack_l4proto *l4proto;
180 pr_debug("destroy_conntrack(%p)\n", ct);
181 NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
182 NF_CT_ASSERT(!timer_pending(&ct->timeout));
184 if (!test_bit(IPS_DYING_BIT, &ct->status))
185 nf_conntrack_event(IPCT_DESTROY, ct);
186 set_bit(IPS_DYING_BIT, &ct->status);
188 /* To make sure we don't get any weird locking issues here:
189 * destroy_conntrack() MUST NOT be called with a write lock
190 * to nf_conntrack_lock!!! -HW */
192 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
193 if (l4proto && l4proto->destroy)
194 l4proto->destroy(ct);
198 spin_lock_bh(&nf_conntrack_lock);
199 /* Expectations will have been removed in clean_from_lists,
200 * except TFTP can create an expectation on the first packet,
201 * before connection is in the list, so we need to clean here,
203 nf_ct_remove_expectations(ct);
205 /* We overload first tuple to link into unconfirmed list. */
206 if (!nf_ct_is_confirmed(ct)) {
207 BUG_ON(hlist_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode));
208 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
211 NF_CT_STAT_INC(net, delete);
212 spin_unlock_bh(&nf_conntrack_lock);
215 nf_ct_put(ct->master);
217 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
218 nf_conntrack_free(ct);
221 static void death_by_timeout(unsigned long ul_conntrack)
223 struct nf_conn *ct = (void *)ul_conntrack;
224 struct net *net = nf_ct_net(ct);
225 struct nf_conn_help *help = nfct_help(ct);
226 struct nf_conntrack_helper *helper;
230 helper = rcu_dereference(help->helper);
231 if (helper && helper->destroy)
236 spin_lock_bh(&nf_conntrack_lock);
237 /* Inside lock so preempt is disabled on module removal path.
238 * Otherwise we can get spurious warnings. */
239 NF_CT_STAT_INC(net, delete_list);
240 clean_from_lists(ct);
241 spin_unlock_bh(&nf_conntrack_lock);
245 struct nf_conntrack_tuple_hash *
246 __nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple)
248 struct nf_conntrack_tuple_hash *h;
249 struct hlist_node *n;
250 unsigned int hash = hash_conntrack(tuple);
252 /* Disable BHs the entire time since we normally need to disable them
253 * at least once for the stats anyway.
256 hlist_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnode) {
257 if (nf_ct_tuple_equal(tuple, &h->tuple)) {
258 NF_CT_STAT_INC(net, found);
262 NF_CT_STAT_INC(net, searched);
268 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
270 /* Find a connection corresponding to a tuple. */
271 struct nf_conntrack_tuple_hash *
272 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple)
274 struct nf_conntrack_tuple_hash *h;
278 h = __nf_conntrack_find(net, tuple);
280 ct = nf_ct_tuplehash_to_ctrack(h);
281 if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
288 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
290 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
292 unsigned int repl_hash)
294 struct net *net = nf_ct_net(ct);
296 hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
297 &net->ct.hash[hash]);
298 hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode,
299 &net->ct.hash[repl_hash]);
302 void nf_conntrack_hash_insert(struct nf_conn *ct)
304 unsigned int hash, repl_hash;
306 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
307 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
309 __nf_conntrack_hash_insert(ct, hash, repl_hash);
311 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
313 /* Confirm a connection given skb; places it in hash table */
315 __nf_conntrack_confirm(struct sk_buff *skb)
317 unsigned int hash, repl_hash;
318 struct nf_conntrack_tuple_hash *h;
320 struct nf_conn_help *help;
321 struct hlist_node *n;
322 enum ip_conntrack_info ctinfo;
325 ct = nf_ct_get(skb, &ctinfo);
328 /* ipt_REJECT uses nf_conntrack_attach to attach related
329 ICMP/TCP RST packets in other direction. Actual packet
330 which created connection will be IP_CT_NEW or for an
331 expected connection, IP_CT_RELATED. */
332 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
335 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
336 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
338 /* We're not in hash table, and we refuse to set up related
339 connections for unconfirmed conns. But packet copies and
340 REJECT will give spurious warnings here. */
341 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
343 /* No external references means noone else could have
345 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
346 pr_debug("Confirming conntrack %p\n", ct);
348 spin_lock_bh(&nf_conntrack_lock);
350 /* See if there's one in the list already, including reverse:
351 NAT could have grabbed it without realizing, since we're
352 not in the hash. If there is, we lost race. */
353 hlist_for_each_entry(h, n, &net->ct.hash[hash], hnode)
354 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
357 hlist_for_each_entry(h, n, &net->ct.hash[repl_hash], hnode)
358 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
362 /* Remove from unconfirmed list */
363 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
365 __nf_conntrack_hash_insert(ct, hash, repl_hash);
366 /* Timer relative to confirmation time, not original
367 setting time, otherwise we'd get timer wrap in
368 weird delay cases. */
369 ct->timeout.expires += jiffies;
370 add_timer(&ct->timeout);
371 atomic_inc(&ct->ct_general.use);
372 set_bit(IPS_CONFIRMED_BIT, &ct->status);
373 NF_CT_STAT_INC(net, insert);
374 spin_unlock_bh(&nf_conntrack_lock);
375 help = nfct_help(ct);
376 if (help && help->helper)
377 nf_conntrack_event_cache(IPCT_HELPER, ct);
378 #ifdef CONFIG_NF_NAT_NEEDED
379 if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
380 test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
381 nf_conntrack_event_cache(IPCT_NATINFO, ct);
383 nf_conntrack_event_cache(master_ct(ct) ?
384 IPCT_RELATED : IPCT_NEW, ct);
388 NF_CT_STAT_INC(net, insert_failed);
389 spin_unlock_bh(&nf_conntrack_lock);
392 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
394 /* Returns true if a connection correspondings to the tuple (required
397 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
398 const struct nf_conn *ignored_conntrack)
400 struct net *net = nf_ct_net(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, &net->ct.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(net, found);
413 rcu_read_unlock_bh();
416 NF_CT_STAT_INC(net, 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(struct net *net, 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, &net->ct.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(net, 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,
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(&net->ct.count);
482 if (nf_conntrack_max &&
483 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
484 unsigned int hash = hash_conntrack(orig);
485 if (!early_drop(net, hash)) {
486 atomic_dec(&net->ct.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(&net->ct.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);
519 struct net *net = nf_ct_net(ct);
522 kmem_cache_free(nf_conntrack_cachep, ct);
523 atomic_dec(&net->ct.count);
526 void nf_conntrack_free(struct nf_conn *ct)
528 nf_ct_ext_destroy(ct);
529 call_rcu(&ct->rcu, nf_conntrack_free_rcu);
531 EXPORT_SYMBOL_GPL(nf_conntrack_free);
533 /* Allocate a new conntrack: we return -ENOMEM if classification
534 failed due to stress. Otherwise it really is unclassifiable. */
535 static struct nf_conntrack_tuple_hash *
536 init_conntrack(struct net *net,
537 const struct nf_conntrack_tuple *tuple,
538 struct nf_conntrack_l3proto *l3proto,
539 struct nf_conntrack_l4proto *l4proto,
541 unsigned int dataoff)
544 struct nf_conn_help *help;
545 struct nf_conntrack_tuple repl_tuple;
546 struct nf_conntrack_expect *exp;
548 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
549 pr_debug("Can't invert tuple.\n");
553 ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC);
555 pr_debug("Can't allocate conntrack.\n");
556 return (struct nf_conntrack_tuple_hash *)ct;
559 if (!l4proto->new(ct, skb, dataoff)) {
560 nf_conntrack_free(ct);
561 pr_debug("init conntrack: can't track with proto module\n");
565 nf_ct_acct_ext_add(ct, GFP_ATOMIC);
567 spin_lock_bh(&nf_conntrack_lock);
568 exp = nf_ct_find_expectation(net, tuple);
570 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
572 /* Welcome, Mr. Bond. We've been expecting you... */
573 __set_bit(IPS_EXPECTED_BIT, &ct->status);
574 ct->master = exp->master;
576 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
578 rcu_assign_pointer(help->helper, exp->helper);
581 #ifdef CONFIG_NF_CONNTRACK_MARK
582 ct->mark = exp->master->mark;
584 #ifdef CONFIG_NF_CONNTRACK_SECMARK
585 ct->secmark = exp->master->secmark;
587 nf_conntrack_get(&ct->master->ct_general);
588 NF_CT_STAT_INC(net, expect_new);
590 __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
591 NF_CT_STAT_INC(net, new);
594 /* Overload tuple linked list to put us in unconfirmed list. */
595 hlist_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
596 &net->ct.unconfirmed);
598 spin_unlock_bh(&nf_conntrack_lock);
602 exp->expectfn(ct, exp);
603 nf_ct_expect_put(exp);
606 return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
609 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
610 static inline struct nf_conn *
611 resolve_normal_ct(struct net *net,
613 unsigned int dataoff,
616 struct nf_conntrack_l3proto *l3proto,
617 struct nf_conntrack_l4proto *l4proto,
619 enum ip_conntrack_info *ctinfo)
621 struct nf_conntrack_tuple tuple;
622 struct nf_conntrack_tuple_hash *h;
625 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
626 dataoff, l3num, protonum, &tuple, l3proto,
628 pr_debug("resolve_normal_ct: Can't get tuple\n");
632 /* look for tuple match */
633 h = nf_conntrack_find_get(net, &tuple);
635 h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff);
641 ct = nf_ct_tuplehash_to_ctrack(h);
643 /* It exists; we have (non-exclusive) reference. */
644 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
645 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
646 /* Please set reply bit if this packet OK */
649 /* Once we've had two way comms, always ESTABLISHED. */
650 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
651 pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
652 *ctinfo = IP_CT_ESTABLISHED;
653 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
654 pr_debug("nf_conntrack_in: related packet for %p\n",
656 *ctinfo = IP_CT_RELATED;
658 pr_debug("nf_conntrack_in: new packet for %p\n", ct);
663 skb->nfct = &ct->ct_general;
664 skb->nfctinfo = *ctinfo;
669 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
673 enum ip_conntrack_info ctinfo;
674 struct nf_conntrack_l3proto *l3proto;
675 struct nf_conntrack_l4proto *l4proto;
676 unsigned int dataoff;
681 /* Previously seen (loopback or untracked)? Ignore. */
683 NF_CT_STAT_INC_ATOMIC(net, ignore);
687 /* rcu_read_lock()ed by nf_hook_slow */
688 l3proto = __nf_ct_l3proto_find(pf);
689 ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
690 &dataoff, &protonum);
692 pr_debug("not prepared to track yet or error occured\n");
693 NF_CT_STAT_INC_ATOMIC(net, error);
694 NF_CT_STAT_INC_ATOMIC(net, invalid);
698 l4proto = __nf_ct_l4proto_find(pf, protonum);
700 /* It may be an special packet, error, unclean...
701 * inverse of the return code tells to the netfilter
702 * core what to do with the packet. */
703 if (l4proto->error != NULL) {
704 ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum);
706 NF_CT_STAT_INC_ATOMIC(net, error);
707 NF_CT_STAT_INC_ATOMIC(net, invalid);
712 ct = resolve_normal_ct(net, skb, dataoff, pf, protonum,
713 l3proto, l4proto, &set_reply, &ctinfo);
715 /* Not valid part of a connection */
716 NF_CT_STAT_INC_ATOMIC(net, invalid);
721 /* Too stressed to deal. */
722 NF_CT_STAT_INC_ATOMIC(net, drop);
726 NF_CT_ASSERT(skb->nfct);
728 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
730 /* Invalid: inverse of the return code tells
731 * the netfilter core what to do */
732 pr_debug("nf_conntrack_in: Can't track with proto module\n");
733 nf_conntrack_put(skb->nfct);
735 NF_CT_STAT_INC_ATOMIC(net, invalid);
739 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
740 nf_conntrack_event_cache(IPCT_STATUS, ct);
744 EXPORT_SYMBOL_GPL(nf_conntrack_in);
746 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
747 const struct nf_conntrack_tuple *orig)
752 ret = nf_ct_invert_tuple(inverse, orig,
753 __nf_ct_l3proto_find(orig->src.l3num),
754 __nf_ct_l4proto_find(orig->src.l3num,
755 orig->dst.protonum));
759 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
761 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
762 implicitly racy: see __nf_conntrack_confirm */
763 void nf_conntrack_alter_reply(struct nf_conn *ct,
764 const struct nf_conntrack_tuple *newreply)
766 struct nf_conn_help *help = nfct_help(ct);
768 /* Should be unconfirmed, so not in hash table yet */
769 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
771 pr_debug("Altering reply tuple of %p to ", ct);
772 nf_ct_dump_tuple(newreply);
774 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
775 if (ct->master || (help && !hlist_empty(&help->expectations)))
779 __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
782 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
784 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
785 void __nf_ct_refresh_acct(struct nf_conn *ct,
786 enum ip_conntrack_info ctinfo,
787 const struct sk_buff *skb,
788 unsigned long extra_jiffies,
793 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
796 spin_lock_bh(&nf_conntrack_lock);
798 /* Only update if this is not a fixed timeout */
799 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
802 /* If not in hash table, timer will not be active yet */
803 if (!nf_ct_is_confirmed(ct)) {
804 ct->timeout.expires = extra_jiffies;
805 event = IPCT_REFRESH;
807 unsigned long newtime = jiffies + extra_jiffies;
809 /* Only update the timeout if the new timeout is at least
810 HZ jiffies from the old timeout. Need del_timer for race
811 avoidance (may already be dying). */
812 if (newtime - ct->timeout.expires >= HZ
813 && del_timer(&ct->timeout)) {
814 ct->timeout.expires = newtime;
815 add_timer(&ct->timeout);
816 event = IPCT_REFRESH;
822 struct nf_conn_counter *acct;
824 acct = nf_conn_acct_find(ct);
826 acct[CTINFO2DIR(ctinfo)].packets++;
827 acct[CTINFO2DIR(ctinfo)].bytes +=
828 skb->len - skb_network_offset(skb);
832 spin_unlock_bh(&nf_conntrack_lock);
834 /* must be unlocked when calling event cache */
836 nf_conntrack_event_cache(event, ct);
838 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
840 bool __nf_ct_kill_acct(struct nf_conn *ct,
841 enum ip_conntrack_info ctinfo,
842 const struct sk_buff *skb,
846 struct nf_conn_counter *acct;
848 spin_lock_bh(&nf_conntrack_lock);
849 acct = nf_conn_acct_find(ct);
851 acct[CTINFO2DIR(ctinfo)].packets++;
852 acct[CTINFO2DIR(ctinfo)].bytes +=
853 skb->len - skb_network_offset(skb);
855 spin_unlock_bh(&nf_conntrack_lock);
858 if (del_timer(&ct->timeout)) {
859 ct->timeout.function((unsigned long)ct);
864 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
866 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
868 #include <linux/netfilter/nfnetlink.h>
869 #include <linux/netfilter/nfnetlink_conntrack.h>
870 #include <linux/mutex.h>
872 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
873 * in ip_conntrack_core, since we don't want the protocols to autoload
874 * or depend on ctnetlink */
875 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
876 const struct nf_conntrack_tuple *tuple)
878 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
879 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
885 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
887 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
888 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
889 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
891 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
893 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
894 struct nf_conntrack_tuple *t)
896 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
899 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
900 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
904 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
907 /* Used by ipt_REJECT and ip6t_REJECT. */
908 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
911 enum ip_conntrack_info ctinfo;
913 /* This ICMP is in reverse direction to the packet which caused it */
914 ct = nf_ct_get(skb, &ctinfo);
915 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
916 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
918 ctinfo = IP_CT_RELATED;
920 /* Attach to new skbuff, and increment count */
921 nskb->nfct = &ct->ct_general;
922 nskb->nfctinfo = ctinfo;
923 nf_conntrack_get(nskb->nfct);
926 /* Bring out ya dead! */
927 static struct nf_conn *
928 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
929 void *data, unsigned int *bucket)
931 struct nf_conntrack_tuple_hash *h;
933 struct hlist_node *n;
935 spin_lock_bh(&nf_conntrack_lock);
936 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
937 hlist_for_each_entry(h, n, &net->ct.hash[*bucket], hnode) {
938 ct = nf_ct_tuplehash_to_ctrack(h);
943 hlist_for_each_entry(h, n, &net->ct.unconfirmed, hnode) {
944 ct = nf_ct_tuplehash_to_ctrack(h);
946 set_bit(IPS_DYING_BIT, &ct->status);
948 spin_unlock_bh(&nf_conntrack_lock);
951 atomic_inc(&ct->ct_general.use);
952 spin_unlock_bh(&nf_conntrack_lock);
956 void nf_ct_iterate_cleanup(struct net *net,
957 int (*iter)(struct nf_conn *i, void *data),
961 unsigned int bucket = 0;
963 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
964 /* Time to push up daises... */
965 if (del_timer(&ct->timeout))
966 death_by_timeout((unsigned long)ct);
967 /* ... else the timer will get him soon. */
972 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
974 struct __nf_ct_flush_report {
979 static int kill_all(struct nf_conn *i, void *data)
981 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
983 /* get_next_corpse sets the dying bit for us */
984 nf_conntrack_event_report(IPCT_DESTROY,
991 void nf_ct_free_hashtable(struct hlist_head *hash, int vmalloced, unsigned int size)
996 free_pages((unsigned long)hash,
997 get_order(sizeof(struct hlist_head) * size));
999 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1001 void nf_conntrack_flush(struct net *net, u32 pid, int report)
1003 struct __nf_ct_flush_report fr = {
1007 nf_ct_iterate_cleanup(net, kill_all, &fr);
1009 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1011 static void nf_conntrack_cleanup_init_net(void)
1013 nf_conntrack_helper_fini();
1014 nf_conntrack_proto_fini();
1015 kmem_cache_destroy(nf_conntrack_cachep);
1018 static void nf_conntrack_cleanup_net(struct net *net)
1020 nf_ct_event_cache_flush(net);
1021 nf_conntrack_ecache_fini(net);
1023 nf_conntrack_flush(net, 0, 0);
1024 if (atomic_read(&net->ct.count) != 0) {
1026 goto i_see_dead_people;
1028 /* wait until all references to nf_conntrack_untracked are dropped */
1029 while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1032 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1033 nf_conntrack_htable_size);
1034 nf_conntrack_acct_fini(net);
1035 nf_conntrack_expect_fini(net);
1036 free_percpu(net->ct.stat);
1039 /* Mishearing the voices in his head, our hero wonders how he's
1040 supposed to kill the mall. */
1041 void nf_conntrack_cleanup(struct net *net)
1043 if (net_eq(net, &init_net))
1044 rcu_assign_pointer(ip_ct_attach, NULL);
1046 /* This makes sure all current packets have passed through
1047 netfilter framework. Roll on, two-stage module
1051 nf_conntrack_cleanup_net(net);
1053 if (net_eq(net, &init_net)) {
1054 rcu_assign_pointer(nf_ct_destroy, NULL);
1055 nf_conntrack_cleanup_init_net();
1059 struct hlist_head *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced)
1061 struct hlist_head *hash;
1062 unsigned int size, i;
1066 size = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_head));
1067 hash = (void*)__get_free_pages(GFP_KERNEL|__GFP_NOWARN,
1068 get_order(sizeof(struct hlist_head)
1072 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1073 hash = vmalloc(sizeof(struct hlist_head) * size);
1077 for (i = 0; i < size; i++)
1078 INIT_HLIST_HEAD(&hash[i]);
1082 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1084 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1086 int i, bucket, vmalloced, old_vmalloced;
1087 unsigned int hashsize, old_size;
1089 struct hlist_head *hash, *old_hash;
1090 struct nf_conntrack_tuple_hash *h;
1092 /* On boot, we can set this without any fancy locking. */
1093 if (!nf_conntrack_htable_size)
1094 return param_set_uint(val, kp);
1096 hashsize = simple_strtoul(val, NULL, 0);
1100 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced);
1104 /* We have to rehahs for the new table anyway, so we also can
1105 * use a newrandom seed */
1106 get_random_bytes(&rnd, 4);
1108 /* Lookups in the old hash might happen in parallel, which means we
1109 * might get false negatives during connection lookup. New connections
1110 * created because of a false negative won't make it into the hash
1111 * though since that required taking the lock.
1113 spin_lock_bh(&nf_conntrack_lock);
1114 for (i = 0; i < nf_conntrack_htable_size; i++) {
1115 while (!hlist_empty(&init_net.ct.hash[i])) {
1116 h = hlist_entry(init_net.ct.hash[i].first,
1117 struct nf_conntrack_tuple_hash, hnode);
1118 hlist_del_rcu(&h->hnode);
1119 bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1120 hlist_add_head(&h->hnode, &hash[bucket]);
1123 old_size = nf_conntrack_htable_size;
1124 old_vmalloced = init_net.ct.hash_vmalloc;
1125 old_hash = init_net.ct.hash;
1127 nf_conntrack_htable_size = hashsize;
1128 init_net.ct.hash_vmalloc = vmalloced;
1129 init_net.ct.hash = hash;
1130 nf_conntrack_hash_rnd = rnd;
1131 spin_unlock_bh(&nf_conntrack_lock);
1133 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1136 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1138 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1139 &nf_conntrack_htable_size, 0600);
1141 static int nf_conntrack_init_init_net(void)
1146 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1147 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1148 if (!nf_conntrack_htable_size) {
1149 nf_conntrack_htable_size
1150 = (((num_physpages << PAGE_SHIFT) / 16384)
1151 / sizeof(struct hlist_head));
1152 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1153 nf_conntrack_htable_size = 16384;
1154 if (nf_conntrack_htable_size < 32)
1155 nf_conntrack_htable_size = 32;
1157 /* Use a max. factor of four by default to get the same max as
1158 * with the old struct list_heads. When a table size is given
1159 * we use the old value of 8 to avoid reducing the max.
1163 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1165 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1166 NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1169 nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1170 sizeof(struct nf_conn),
1172 if (!nf_conntrack_cachep) {
1173 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1178 ret = nf_conntrack_proto_init();
1182 ret = nf_conntrack_helper_init();
1189 nf_conntrack_proto_fini();
1191 kmem_cache_destroy(nf_conntrack_cachep);
1196 static int nf_conntrack_init_net(struct net *net)
1200 atomic_set(&net->ct.count, 0);
1201 INIT_HLIST_HEAD(&net->ct.unconfirmed);
1202 net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1203 if (!net->ct.stat) {
1207 ret = nf_conntrack_ecache_init(net);
1210 net->ct.hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1211 &net->ct.hash_vmalloc);
1212 if (!net->ct.hash) {
1214 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1217 ret = nf_conntrack_expect_init(net);
1220 ret = nf_conntrack_acct_init(net);
1224 /* Set up fake conntrack:
1225 - to never be deleted, not in any hashes */
1226 #ifdef CONFIG_NET_NS
1227 nf_conntrack_untracked.ct_net = &init_net;
1229 atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1230 /* - and look it like as a confirmed connection */
1231 set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1236 nf_conntrack_expect_fini(net);
1238 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1239 nf_conntrack_htable_size);
1241 nf_conntrack_ecache_fini(net);
1243 free_percpu(net->ct.stat);
1248 int nf_conntrack_init(struct net *net)
1252 if (net_eq(net, &init_net)) {
1253 ret = nf_conntrack_init_init_net();
1257 ret = nf_conntrack_init_net(net);
1261 if (net_eq(net, &init_net)) {
1262 /* For use by REJECT target */
1263 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1264 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1269 if (net_eq(net, &init_net))
1270 nf_conntrack_cleanup_init_net();