1 /* Connection state tracking for netfilter. This is separated from,
2 but required by, the NAT layer; it can also be used by an iptables
5 /* (C) 1999-2001 Paul `Rusty' Russell
6 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
7 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/types.h>
15 #include <linux/netfilter.h>
16 #include <linux/module.h>
17 #include <linux/skbuff.h>
18 #include <linux/proc_fs.h>
19 #include <linux/vmalloc.h>
20 #include <linux/stddef.h>
21 #include <linux/slab.h>
22 #include <linux/random.h>
23 #include <linux/jhash.h>
24 #include <linux/err.h>
25 #include <linux/percpu.h>
26 #include <linux/moduleparam.h>
27 #include <linux/notifier.h>
28 #include <linux/kernel.h>
29 #include <linux/netdevice.h>
30 #include <linux/socket.h>
33 #include <net/netfilter/nf_conntrack.h>
34 #include <net/netfilter/nf_conntrack_l3proto.h>
35 #include <net/netfilter/nf_conntrack_l4proto.h>
36 #include <net/netfilter/nf_conntrack_expect.h>
37 #include <net/netfilter/nf_conntrack_helper.h>
38 #include <net/netfilter/nf_conntrack_core.h>
39 #include <net/netfilter/nf_conntrack_extend.h>
41 #define NF_CONNTRACK_VERSION "0.5.0"
43 DEFINE_SPINLOCK(nf_conntrack_lock);
44 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
46 /* nf_conntrack_standalone needs this */
47 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
48 EXPORT_SYMBOL_GPL(nf_conntrack_count);
50 unsigned int nf_conntrack_htable_size __read_mostly;
51 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
53 int nf_conntrack_max __read_mostly;
54 EXPORT_SYMBOL_GPL(nf_conntrack_max);
56 struct hlist_head *nf_conntrack_hash __read_mostly;
57 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
59 struct nf_conn nf_conntrack_untracked __read_mostly;
60 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
62 unsigned int nf_ct_log_invalid __read_mostly;
63 HLIST_HEAD(unconfirmed);
64 static int nf_conntrack_vmalloc __read_mostly;
65 static struct kmem_cache *nf_conntrack_cachep __read_mostly;
67 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
68 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
70 static int nf_conntrack_hash_rnd_initted;
71 static unsigned int nf_conntrack_hash_rnd;
73 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
74 unsigned int size, unsigned int rnd)
79 /* The direction must be ignored, so we hash everything up to the
80 * destination ports (which is a multiple of 4) and treat the last
81 * three bytes manually.
83 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
84 h = jhash2((u32 *)tuple, n,
85 rnd ^ (((__force __u16)tuple->dst.u.all << 16) |
86 tuple->dst.protonum));
88 return ((u64)h * size) >> 32;
91 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
93 return __hash_conntrack(tuple, nf_conntrack_htable_size,
94 nf_conntrack_hash_rnd);
98 nf_ct_get_tuple(const struct sk_buff *skb,
100 unsigned int dataoff,
103 struct nf_conntrack_tuple *tuple,
104 const struct nf_conntrack_l3proto *l3proto,
105 const struct nf_conntrack_l4proto *l4proto)
107 memset(tuple, 0, sizeof(*tuple));
109 tuple->src.l3num = l3num;
110 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
113 tuple->dst.protonum = protonum;
114 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
116 return l4proto->pkt_to_tuple(skb, dataoff, tuple);
118 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
120 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
121 u_int16_t l3num, struct nf_conntrack_tuple *tuple)
123 struct nf_conntrack_l3proto *l3proto;
124 struct nf_conntrack_l4proto *l4proto;
125 unsigned int protoff;
131 l3proto = __nf_ct_l3proto_find(l3num);
132 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
133 if (ret != NF_ACCEPT) {
138 l4proto = __nf_ct_l4proto_find(l3num, protonum);
140 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
146 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
149 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
150 const struct nf_conntrack_tuple *orig,
151 const struct nf_conntrack_l3proto *l3proto,
152 const struct nf_conntrack_l4proto *l4proto)
154 memset(inverse, 0, sizeof(*inverse));
156 inverse->src.l3num = orig->src.l3num;
157 if (l3proto->invert_tuple(inverse, orig) == 0)
160 inverse->dst.dir = !orig->dst.dir;
162 inverse->dst.protonum = orig->dst.protonum;
163 return l4proto->invert_tuple(inverse, orig);
165 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
168 clean_from_lists(struct nf_conn *ct)
170 pr_debug("clean_from_lists(%p)\n", ct);
171 hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
172 hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode);
174 /* Destroy all pending expectations */
175 nf_ct_remove_expectations(ct);
179 destroy_conntrack(struct nf_conntrack *nfct)
181 struct nf_conn *ct = (struct nf_conn *)nfct;
182 struct nf_conntrack_l4proto *l4proto;
184 pr_debug("destroy_conntrack(%p)\n", ct);
185 NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
186 NF_CT_ASSERT(!timer_pending(&ct->timeout));
188 nf_conntrack_event(IPCT_DESTROY, ct);
189 set_bit(IPS_DYING_BIT, &ct->status);
191 /* To make sure we don't get any weird locking issues here:
192 * destroy_conntrack() MUST NOT be called with a write lock
193 * to nf_conntrack_lock!!! -HW */
195 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
196 if (l4proto && l4proto->destroy)
197 l4proto->destroy(ct);
201 spin_lock_bh(&nf_conntrack_lock);
202 /* Expectations will have been removed in clean_from_lists,
203 * except TFTP can create an expectation on the first packet,
204 * before connection is in the list, so we need to clean here,
206 nf_ct_remove_expectations(ct);
208 /* We overload first tuple to link into unconfirmed list. */
209 if (!nf_ct_is_confirmed(ct)) {
210 BUG_ON(hlist_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode));
211 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
214 NF_CT_STAT_INC(delete);
215 spin_unlock_bh(&nf_conntrack_lock);
218 nf_ct_put(ct->master);
220 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
221 nf_conntrack_free(ct);
224 static void death_by_timeout(unsigned long ul_conntrack)
226 struct nf_conn *ct = (void *)ul_conntrack;
227 struct nf_conn_help *help = nfct_help(ct);
228 struct nf_conntrack_helper *helper;
232 helper = rcu_dereference(help->helper);
233 if (helper && helper->destroy)
238 spin_lock_bh(&nf_conntrack_lock);
239 /* Inside lock so preempt is disabled on module removal path.
240 * Otherwise we can get spurious warnings. */
241 NF_CT_STAT_INC(delete_list);
242 clean_from_lists(ct);
243 spin_unlock_bh(&nf_conntrack_lock);
247 struct nf_conntrack_tuple_hash *
248 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple)
250 struct nf_conntrack_tuple_hash *h;
251 struct hlist_node *n;
252 unsigned int hash = hash_conntrack(tuple);
254 /* Disable BHs the entire time since we normally need to disable them
255 * at least once for the stats anyway.
258 hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash], hnode) {
259 if (nf_ct_tuple_equal(tuple, &h->tuple)) {
260 NF_CT_STAT_INC(found);
264 NF_CT_STAT_INC(searched);
270 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
272 /* Find a connection corresponding to a tuple. */
273 struct nf_conntrack_tuple_hash *
274 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple)
276 struct nf_conntrack_tuple_hash *h;
280 h = __nf_conntrack_find(tuple);
282 ct = nf_ct_tuplehash_to_ctrack(h);
283 if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
290 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
292 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
294 unsigned int repl_hash)
296 hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
297 &nf_conntrack_hash[hash]);
298 hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode,
299 &nf_conntrack_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 spin_lock_bh(&nf_conntrack_lock);
310 __nf_conntrack_hash_insert(ct, hash, repl_hash);
311 spin_unlock_bh(&nf_conntrack_lock);
313 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
315 /* Confirm a connection given skb; places it in hash table */
317 __nf_conntrack_confirm(struct sk_buff *skb)
319 unsigned int hash, repl_hash;
320 struct nf_conntrack_tuple_hash *h;
322 struct nf_conn_help *help;
323 struct hlist_node *n;
324 enum ip_conntrack_info ctinfo;
326 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, &nf_conntrack_hash[hash], hnode)
354 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
357 hlist_for_each_entry(h, n, &nf_conntrack_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(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, skb);
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, skb);
383 nf_conntrack_event_cache(master_ct(ct) ?
384 IPCT_RELATED : IPCT_NEW, skb);
388 NF_CT_STAT_INC(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 nf_conntrack_tuple_hash *h;
401 struct hlist_node *n;
402 unsigned int hash = hash_conntrack(tuple);
404 /* Disable BHs the entire time since we need to disable them at
405 * least once for the stats anyway.
408 hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash], hnode) {
409 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
410 nf_ct_tuple_equal(tuple, &h->tuple)) {
411 NF_CT_STAT_INC(found);
412 rcu_read_unlock_bh();
415 NF_CT_STAT_INC(searched);
417 rcu_read_unlock_bh();
421 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
423 #define NF_CT_EVICTION_RANGE 8
425 /* There's a small race here where we may free a just-assured
426 connection. Too bad: we're in trouble anyway. */
427 static noinline int early_drop(unsigned int hash)
429 /* Use oldest entry, which is roughly LRU */
430 struct nf_conntrack_tuple_hash *h;
431 struct nf_conn *ct = NULL, *tmp;
432 struct hlist_node *n;
433 unsigned int i, cnt = 0;
437 for (i = 0; i < nf_conntrack_htable_size; i++) {
438 hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash],
440 tmp = nf_ct_tuplehash_to_ctrack(h);
441 if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
446 if (ct && unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
448 if (ct || cnt >= NF_CT_EVICTION_RANGE)
450 hash = (hash + 1) % nf_conntrack_htable_size;
457 if (del_timer(&ct->timeout)) {
458 death_by_timeout((unsigned long)ct);
460 NF_CT_STAT_INC_ATOMIC(early_drop);
466 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
467 const struct nf_conntrack_tuple *repl,
470 struct nf_conn *ct = NULL;
472 if (unlikely(!nf_conntrack_hash_rnd_initted)) {
473 get_random_bytes(&nf_conntrack_hash_rnd, 4);
474 nf_conntrack_hash_rnd_initted = 1;
477 /* We don't want any race condition at early drop stage */
478 atomic_inc(&nf_conntrack_count);
480 if (nf_conntrack_max &&
481 unlikely(atomic_read(&nf_conntrack_count) > nf_conntrack_max)) {
482 unsigned int hash = hash_conntrack(orig);
483 if (!early_drop(hash)) {
484 atomic_dec(&nf_conntrack_count);
487 "nf_conntrack: table full, dropping"
489 return ERR_PTR(-ENOMEM);
493 ct = kmem_cache_zalloc(nf_conntrack_cachep, gfp);
495 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
496 atomic_dec(&nf_conntrack_count);
497 return ERR_PTR(-ENOMEM);
500 atomic_set(&ct->ct_general.use, 1);
501 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
502 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
503 /* Don't set timer yet: wait for confirmation */
504 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
505 INIT_RCU_HEAD(&ct->rcu);
509 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
511 static void nf_conntrack_free_rcu(struct rcu_head *head)
513 struct nf_conn *ct = container_of(head, struct nf_conn, rcu);
516 kmem_cache_free(nf_conntrack_cachep, ct);
517 atomic_dec(&nf_conntrack_count);
520 void nf_conntrack_free(struct nf_conn *ct)
522 nf_ct_ext_destroy(ct);
523 call_rcu(&ct->rcu, nf_conntrack_free_rcu);
525 EXPORT_SYMBOL_GPL(nf_conntrack_free);
527 /* Allocate a new conntrack: we return -ENOMEM if classification
528 failed due to stress. Otherwise it really is unclassifiable. */
529 static struct nf_conntrack_tuple_hash *
530 init_conntrack(const struct nf_conntrack_tuple *tuple,
531 struct nf_conntrack_l3proto *l3proto,
532 struct nf_conntrack_l4proto *l4proto,
534 unsigned int dataoff)
537 struct nf_conn_help *help;
538 struct nf_conntrack_tuple repl_tuple;
539 struct nf_conntrack_expect *exp;
541 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
542 pr_debug("Can't invert tuple.\n");
546 ct = nf_conntrack_alloc(tuple, &repl_tuple, GFP_ATOMIC);
547 if (ct == NULL || IS_ERR(ct)) {
548 pr_debug("Can't allocate conntrack.\n");
549 return (struct nf_conntrack_tuple_hash *)ct;
552 if (!l4proto->new(ct, skb, dataoff)) {
553 nf_conntrack_free(ct);
554 pr_debug("init conntrack: can't track with proto module\n");
558 spin_lock_bh(&nf_conntrack_lock);
559 exp = nf_ct_find_expectation(tuple);
561 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
563 /* Welcome, Mr. Bond. We've been expecting you... */
564 __set_bit(IPS_EXPECTED_BIT, &ct->status);
565 ct->master = exp->master;
567 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
569 rcu_assign_pointer(help->helper, exp->helper);
572 #ifdef CONFIG_NF_CONNTRACK_MARK
573 ct->mark = exp->master->mark;
575 #ifdef CONFIG_NF_CONNTRACK_SECMARK
576 ct->secmark = exp->master->secmark;
578 nf_conntrack_get(&ct->master->ct_general);
579 NF_CT_STAT_INC(expect_new);
581 struct nf_conntrack_helper *helper;
583 helper = __nf_ct_helper_find(&repl_tuple);
585 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
587 rcu_assign_pointer(help->helper, helper);
592 /* Overload tuple linked list to put us in unconfirmed list. */
593 hlist_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode, &unconfirmed);
595 spin_unlock_bh(&nf_conntrack_lock);
599 exp->expectfn(ct, exp);
600 nf_ct_expect_put(exp);
603 return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
606 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
607 static inline struct nf_conn *
608 resolve_normal_ct(struct sk_buff *skb,
609 unsigned int dataoff,
612 struct nf_conntrack_l3proto *l3proto,
613 struct nf_conntrack_l4proto *l4proto,
615 enum ip_conntrack_info *ctinfo)
617 struct nf_conntrack_tuple tuple;
618 struct nf_conntrack_tuple_hash *h;
621 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
622 dataoff, l3num, protonum, &tuple, l3proto,
624 pr_debug("resolve_normal_ct: Can't get tuple\n");
628 /* look for tuple match */
629 h = nf_conntrack_find_get(&tuple);
631 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
637 ct = nf_ct_tuplehash_to_ctrack(h);
639 /* It exists; we have (non-exclusive) reference. */
640 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
641 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
642 /* Please set reply bit if this packet OK */
645 /* Once we've had two way comms, always ESTABLISHED. */
646 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
647 pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
648 *ctinfo = IP_CT_ESTABLISHED;
649 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
650 pr_debug("nf_conntrack_in: related packet for %p\n",
652 *ctinfo = IP_CT_RELATED;
654 pr_debug("nf_conntrack_in: new packet for %p\n", ct);
659 skb->nfct = &ct->ct_general;
660 skb->nfctinfo = *ctinfo;
665 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff *skb)
668 enum ip_conntrack_info ctinfo;
669 struct nf_conntrack_l3proto *l3proto;
670 struct nf_conntrack_l4proto *l4proto;
671 unsigned int dataoff;
676 /* Previously seen (loopback or untracked)? Ignore. */
678 NF_CT_STAT_INC_ATOMIC(ignore);
682 /* rcu_read_lock()ed by nf_hook_slow */
683 l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
684 ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
685 &dataoff, &protonum);
687 pr_debug("not prepared to track yet or error occured\n");
688 NF_CT_STAT_INC_ATOMIC(error);
689 NF_CT_STAT_INC_ATOMIC(invalid);
693 l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
695 /* It may be an special packet, error, unclean...
696 * inverse of the return code tells to the netfilter
697 * core what to do with the packet. */
698 if (l4proto->error != NULL &&
699 (ret = l4proto->error(skb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
700 NF_CT_STAT_INC_ATOMIC(error);
701 NF_CT_STAT_INC_ATOMIC(invalid);
705 ct = resolve_normal_ct(skb, dataoff, pf, protonum, l3proto, l4proto,
706 &set_reply, &ctinfo);
708 /* Not valid part of a connection */
709 NF_CT_STAT_INC_ATOMIC(invalid);
714 /* Too stressed to deal. */
715 NF_CT_STAT_INC_ATOMIC(drop);
719 NF_CT_ASSERT(skb->nfct);
721 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
723 /* Invalid: inverse of the return code tells
724 * the netfilter core what to do */
725 pr_debug("nf_conntrack_in: Can't track with proto module\n");
726 nf_conntrack_put(skb->nfct);
728 NF_CT_STAT_INC_ATOMIC(invalid);
732 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
733 nf_conntrack_event_cache(IPCT_STATUS, skb);
737 EXPORT_SYMBOL_GPL(nf_conntrack_in);
739 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
740 const struct nf_conntrack_tuple *orig)
745 ret = nf_ct_invert_tuple(inverse, orig,
746 __nf_ct_l3proto_find(orig->src.l3num),
747 __nf_ct_l4proto_find(orig->src.l3num,
748 orig->dst.protonum));
752 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
754 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
755 implicitly racy: see __nf_conntrack_confirm */
756 void nf_conntrack_alter_reply(struct nf_conn *ct,
757 const struct nf_conntrack_tuple *newreply)
759 struct nf_conn_help *help = nfct_help(ct);
760 struct nf_conntrack_helper *helper;
762 /* Should be unconfirmed, so not in hash table yet */
763 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
765 pr_debug("Altering reply tuple of %p to ", ct);
766 nf_ct_dump_tuple(newreply);
768 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
769 if (ct->master || (help && !hlist_empty(&help->expectations)))
773 helper = __nf_ct_helper_find(newreply);
774 if (helper == NULL) {
776 rcu_assign_pointer(help->helper, NULL);
781 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
785 memset(&help->help, 0, sizeof(help->help));
788 rcu_assign_pointer(help->helper, helper);
792 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
794 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
795 void __nf_ct_refresh_acct(struct nf_conn *ct,
796 enum ip_conntrack_info ctinfo,
797 const struct sk_buff *skb,
798 unsigned long extra_jiffies,
803 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
806 spin_lock_bh(&nf_conntrack_lock);
808 /* Only update if this is not a fixed timeout */
809 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
812 /* If not in hash table, timer will not be active yet */
813 if (!nf_ct_is_confirmed(ct)) {
814 ct->timeout.expires = extra_jiffies;
815 event = IPCT_REFRESH;
817 unsigned long newtime = jiffies + extra_jiffies;
819 /* Only update the timeout if the new timeout is at least
820 HZ jiffies from the old timeout. Need del_timer for race
821 avoidance (may already be dying). */
822 if (newtime - ct->timeout.expires >= HZ
823 && del_timer(&ct->timeout)) {
824 ct->timeout.expires = newtime;
825 add_timer(&ct->timeout);
826 event = IPCT_REFRESH;
831 #ifdef CONFIG_NF_CT_ACCT
833 ct->counters[CTINFO2DIR(ctinfo)].packets++;
834 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
835 skb->len - skb_network_offset(skb);
837 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
838 || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
839 event |= IPCT_COUNTER_FILLING;
843 spin_unlock_bh(&nf_conntrack_lock);
845 /* must be unlocked when calling event cache */
847 nf_conntrack_event_cache(event, skb);
849 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
851 bool __nf_ct_kill_acct(struct nf_conn *ct,
852 enum ip_conntrack_info ctinfo,
853 const struct sk_buff *skb,
856 #ifdef CONFIG_NF_CT_ACCT
858 spin_lock_bh(&nf_conntrack_lock);
859 ct->counters[CTINFO2DIR(ctinfo)].packets++;
860 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
861 skb->len - skb_network_offset(skb);
862 spin_unlock_bh(&nf_conntrack_lock);
865 if (del_timer(&ct->timeout)) {
866 ct->timeout.function((unsigned long)ct);
871 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
873 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
875 #include <linux/netfilter/nfnetlink.h>
876 #include <linux/netfilter/nfnetlink_conntrack.h>
877 #include <linux/mutex.h>
879 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
880 * in ip_conntrack_core, since we don't want the protocols to autoload
881 * or depend on ctnetlink */
882 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
883 const struct nf_conntrack_tuple *tuple)
885 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
886 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
892 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
894 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
895 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
896 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
898 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
900 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
901 struct nf_conntrack_tuple *t)
903 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
906 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
907 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
911 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
914 /* Used by ipt_REJECT and ip6t_REJECT. */
915 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
918 enum ip_conntrack_info ctinfo;
920 /* This ICMP is in reverse direction to the packet which caused it */
921 ct = nf_ct_get(skb, &ctinfo);
922 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
923 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
925 ctinfo = IP_CT_RELATED;
927 /* Attach to new skbuff, and increment count */
928 nskb->nfct = &ct->ct_general;
929 nskb->nfctinfo = ctinfo;
930 nf_conntrack_get(nskb->nfct);
933 /* Bring out ya dead! */
934 static struct nf_conn *
935 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
936 void *data, unsigned int *bucket)
938 struct nf_conntrack_tuple_hash *h;
940 struct hlist_node *n;
942 spin_lock_bh(&nf_conntrack_lock);
943 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
944 hlist_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnode) {
945 ct = nf_ct_tuplehash_to_ctrack(h);
950 hlist_for_each_entry(h, n, &unconfirmed, hnode) {
951 ct = nf_ct_tuplehash_to_ctrack(h);
953 set_bit(IPS_DYING_BIT, &ct->status);
955 spin_unlock_bh(&nf_conntrack_lock);
958 atomic_inc(&ct->ct_general.use);
959 spin_unlock_bh(&nf_conntrack_lock);
964 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
967 unsigned int bucket = 0;
969 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
970 /* Time to push up daises... */
971 if (del_timer(&ct->timeout))
972 death_by_timeout((unsigned long)ct);
973 /* ... else the timer will get him soon. */
978 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
980 static int kill_all(struct nf_conn *i, void *data)
985 void nf_ct_free_hashtable(struct hlist_head *hash, int vmalloced, unsigned int size)
990 free_pages((unsigned long)hash,
991 get_order(sizeof(struct hlist_head) * size));
993 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
995 void nf_conntrack_flush(void)
997 nf_ct_iterate_cleanup(kill_all, NULL);
999 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1001 /* Mishearing the voices in his head, our hero wonders how he's
1002 supposed to kill the mall. */
1003 void nf_conntrack_cleanup(void)
1005 rcu_assign_pointer(ip_ct_attach, NULL);
1007 /* This makes sure all current packets have passed through
1008 netfilter framework. Roll on, two-stage module
1012 nf_ct_event_cache_flush();
1014 nf_conntrack_flush();
1015 if (atomic_read(&nf_conntrack_count) != 0) {
1017 goto i_see_dead_people;
1019 /* wait until all references to nf_conntrack_untracked are dropped */
1020 while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1023 rcu_assign_pointer(nf_ct_destroy, NULL);
1025 kmem_cache_destroy(nf_conntrack_cachep);
1026 nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
1027 nf_conntrack_htable_size);
1029 nf_conntrack_proto_fini();
1030 nf_conntrack_helper_fini();
1031 nf_conntrack_expect_fini();
1034 struct hlist_head *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced)
1036 struct hlist_head *hash;
1037 unsigned int size, i;
1041 size = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_head));
1042 hash = (void*)__get_free_pages(GFP_KERNEL|__GFP_NOWARN,
1043 get_order(sizeof(struct hlist_head)
1047 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1048 hash = vmalloc(sizeof(struct hlist_head) * size);
1052 for (i = 0; i < size; i++)
1053 INIT_HLIST_HEAD(&hash[i]);
1057 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1059 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1061 int i, bucket, vmalloced, old_vmalloced;
1062 unsigned int hashsize, old_size;
1064 struct hlist_head *hash, *old_hash;
1065 struct nf_conntrack_tuple_hash *h;
1067 /* On boot, we can set this without any fancy locking. */
1068 if (!nf_conntrack_htable_size)
1069 return param_set_uint(val, kp);
1071 hashsize = simple_strtoul(val, NULL, 0);
1075 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced);
1079 /* We have to rehahs for the new table anyway, so we also can
1080 * use a newrandom seed */
1081 get_random_bytes(&rnd, 4);
1083 /* Lookups in the old hash might happen in parallel, which means we
1084 * might get false negatives during connection lookup. New connections
1085 * created because of a false negative won't make it into the hash
1086 * though since that required taking the lock.
1088 spin_lock_bh(&nf_conntrack_lock);
1089 for (i = 0; i < nf_conntrack_htable_size; i++) {
1090 while (!hlist_empty(&nf_conntrack_hash[i])) {
1091 h = hlist_entry(nf_conntrack_hash[i].first,
1092 struct nf_conntrack_tuple_hash, hnode);
1093 hlist_del_rcu(&h->hnode);
1094 bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1095 hlist_add_head(&h->hnode, &hash[bucket]);
1098 old_size = nf_conntrack_htable_size;
1099 old_vmalloced = nf_conntrack_vmalloc;
1100 old_hash = nf_conntrack_hash;
1102 nf_conntrack_htable_size = hashsize;
1103 nf_conntrack_vmalloc = vmalloced;
1104 nf_conntrack_hash = hash;
1105 nf_conntrack_hash_rnd = rnd;
1106 spin_unlock_bh(&nf_conntrack_lock);
1108 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1111 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1113 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1114 &nf_conntrack_htable_size, 0600);
1116 int __init nf_conntrack_init(void)
1121 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
1122 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1123 if (!nf_conntrack_htable_size) {
1124 nf_conntrack_htable_size
1125 = (((num_physpages << PAGE_SHIFT) / 16384)
1126 / sizeof(struct hlist_head));
1127 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1128 nf_conntrack_htable_size = 16384;
1129 if (nf_conntrack_htable_size < 32)
1130 nf_conntrack_htable_size = 32;
1132 /* Use a max. factor of four by default to get the same max as
1133 * with the old struct list_heads. When a table size is given
1134 * we use the old value of 8 to avoid reducing the max.
1138 nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1139 &nf_conntrack_vmalloc);
1140 if (!nf_conntrack_hash) {
1141 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1145 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1147 printk("nf_conntrack version %s (%u buckets, %d max)\n",
1148 NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1151 nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1152 sizeof(struct nf_conn),
1154 if (!nf_conntrack_cachep) {
1155 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1159 ret = nf_conntrack_proto_init();
1161 goto err_free_conntrack_slab;
1163 ret = nf_conntrack_expect_init();
1165 goto out_fini_proto;
1167 ret = nf_conntrack_helper_init();
1169 goto out_fini_expect;
1171 /* For use by REJECT target */
1172 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1173 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1175 /* Set up fake conntrack:
1176 - to never be deleted, not in any hashes */
1177 atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1178 /* - and look it like as a confirmed connection */
1179 set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1184 nf_conntrack_expect_fini();
1186 nf_conntrack_proto_fini();
1187 err_free_conntrack_slab:
1188 kmem_cache_destroy(nf_conntrack_cachep);
1190 nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
1191 nf_conntrack_htable_size);