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>
8 * (C) 2005-2012 Patrick McHardy <kaber@trash.net>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 #include <linux/types.h>
18 #include <linux/netfilter.h>
19 #include <linux/module.h>
20 #include <linux/sched.h>
21 #include <linux/skbuff.h>
22 #include <linux/proc_fs.h>
23 #include <linux/vmalloc.h>
24 #include <linux/stddef.h>
25 #include <linux/slab.h>
26 #include <linux/random.h>
27 #include <linux/jhash.h>
28 #include <linux/err.h>
29 #include <linux/percpu.h>
30 #include <linux/moduleparam.h>
31 #include <linux/notifier.h>
32 #include <linux/kernel.h>
33 #include <linux/netdevice.h>
34 #include <linux/socket.h>
36 #include <linux/nsproxy.h>
37 #include <linux/rculist_nulls.h>
39 #include <net/netfilter/nf_conntrack.h>
40 #include <net/netfilter/nf_conntrack_l3proto.h>
41 #include <net/netfilter/nf_conntrack_l4proto.h>
42 #include <net/netfilter/nf_conntrack_expect.h>
43 #include <net/netfilter/nf_conntrack_helper.h>
44 #include <net/netfilter/nf_conntrack_seqadj.h>
45 #include <net/netfilter/nf_conntrack_core.h>
46 #include <net/netfilter/nf_conntrack_extend.h>
47 #include <net/netfilter/nf_conntrack_acct.h>
48 #include <net/netfilter/nf_conntrack_ecache.h>
49 #include <net/netfilter/nf_conntrack_zones.h>
50 #include <net/netfilter/nf_conntrack_timestamp.h>
51 #include <net/netfilter/nf_conntrack_timeout.h>
52 #include <net/netfilter/nf_conntrack_labels.h>
53 #include <net/netfilter/nf_conntrack_synproxy.h>
54 #include <net/netfilter/nf_nat.h>
55 #include <net/netfilter/nf_nat_core.h>
56 #include <net/netfilter/nf_nat_helper.h>
57 #include <net/netns/hash.h>
59 #include "nf_internals.h"
61 #define NF_CONNTRACK_VERSION "0.5.0"
63 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
64 enum nf_nat_manip_type manip,
65 const struct nlattr *attr) __read_mostly;
66 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
68 __cacheline_aligned_in_smp spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS];
69 EXPORT_SYMBOL_GPL(nf_conntrack_locks);
71 __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock);
72 EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock);
74 struct hlist_nulls_head *nf_conntrack_hash __read_mostly;
75 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
77 struct conntrack_gc_work {
78 struct delayed_work dwork;
85 static __read_mostly struct kmem_cache *nf_conntrack_cachep;
86 static __read_mostly spinlock_t nf_conntrack_locks_all_lock;
87 static __read_mostly DEFINE_SPINLOCK(nf_conntrack_locks_all_lock);
88 static __read_mostly bool nf_conntrack_locks_all;
90 /* every gc cycle scans at most 1/GC_MAX_BUCKETS_DIV part of table */
91 #define GC_MAX_BUCKETS_DIV 128u
92 /* upper bound of full table scan */
93 #define GC_MAX_SCAN_JIFFIES (16u * HZ)
94 /* desired ratio of entries found to be expired */
95 #define GC_EVICT_RATIO 50u
97 static struct conntrack_gc_work conntrack_gc_work;
99 void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
101 /* 1) Acquire the lock */
104 /* 2) read nf_conntrack_locks_all, with ACQUIRE semantics
105 * It pairs with the smp_store_release() in nf_conntrack_all_unlock()
107 if (likely(smp_load_acquire(&nf_conntrack_locks_all) == false))
110 /* fast path failed, unlock */
113 /* Slow path 1) get global lock */
114 spin_lock(&nf_conntrack_locks_all_lock);
116 /* Slow path 2) get the lock we want */
119 /* Slow path 3) release the global lock */
120 spin_unlock(&nf_conntrack_locks_all_lock);
122 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
124 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2)
126 h1 %= CONNTRACK_LOCKS;
127 h2 %= CONNTRACK_LOCKS;
128 spin_unlock(&nf_conntrack_locks[h1]);
130 spin_unlock(&nf_conntrack_locks[h2]);
133 /* return true if we need to recompute hashes (in case hash table was resized) */
134 static bool nf_conntrack_double_lock(struct net *net, unsigned int h1,
135 unsigned int h2, unsigned int sequence)
137 h1 %= CONNTRACK_LOCKS;
138 h2 %= CONNTRACK_LOCKS;
140 nf_conntrack_lock(&nf_conntrack_locks[h1]);
142 spin_lock_nested(&nf_conntrack_locks[h2],
143 SINGLE_DEPTH_NESTING);
145 nf_conntrack_lock(&nf_conntrack_locks[h2]);
146 spin_lock_nested(&nf_conntrack_locks[h1],
147 SINGLE_DEPTH_NESTING);
149 if (read_seqcount_retry(&nf_conntrack_generation, sequence)) {
150 nf_conntrack_double_unlock(h1, h2);
156 static void nf_conntrack_all_lock(void)
160 spin_lock(&nf_conntrack_locks_all_lock);
162 nf_conntrack_locks_all = true;
164 for (i = 0; i < CONNTRACK_LOCKS; i++) {
165 spin_lock(&nf_conntrack_locks[i]);
167 /* This spin_unlock provides the "release" to ensure that
168 * nf_conntrack_locks_all==true is visible to everyone that
169 * acquired spin_lock(&nf_conntrack_locks[]).
171 spin_unlock(&nf_conntrack_locks[i]);
175 static void nf_conntrack_all_unlock(void)
177 /* All prior stores must be complete before we clear
178 * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
179 * might observe the false value but not the entire
181 * It pairs with the smp_load_acquire() in nf_conntrack_lock()
183 smp_store_release(&nf_conntrack_locks_all, false);
184 spin_unlock(&nf_conntrack_locks_all_lock);
187 unsigned int nf_conntrack_htable_size __read_mostly;
188 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
190 unsigned int nf_conntrack_max __read_mostly;
191 seqcount_t nf_conntrack_generation __read_mostly;
192 static unsigned int nf_conntrack_hash_rnd __read_mostly;
194 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
195 const struct net *net)
200 get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
202 /* The direction must be ignored, so we hash everything up to the
203 * destination ports (which is a multiple of 4) and treat the last
204 * three bytes manually.
206 seed = nf_conntrack_hash_rnd ^ net_hash_mix(net);
207 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
208 return jhash2((u32 *)tuple, n, seed ^
209 (((__force __u16)tuple->dst.u.all << 16) |
210 tuple->dst.protonum));
213 static u32 scale_hash(u32 hash)
215 return reciprocal_scale(hash, nf_conntrack_htable_size);
218 static u32 __hash_conntrack(const struct net *net,
219 const struct nf_conntrack_tuple *tuple,
222 return reciprocal_scale(hash_conntrack_raw(tuple, net), size);
225 static u32 hash_conntrack(const struct net *net,
226 const struct nf_conntrack_tuple *tuple)
228 return scale_hash(hash_conntrack_raw(tuple, net));
232 nf_ct_get_tuple(const struct sk_buff *skb,
234 unsigned int dataoff,
238 struct nf_conntrack_tuple *tuple,
239 const struct nf_conntrack_l3proto *l3proto,
240 const struct nf_conntrack_l4proto *l4proto)
242 memset(tuple, 0, sizeof(*tuple));
244 tuple->src.l3num = l3num;
245 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
248 tuple->dst.protonum = protonum;
249 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
251 return l4proto->pkt_to_tuple(skb, dataoff, net, tuple);
253 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
255 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
257 struct net *net, struct nf_conntrack_tuple *tuple)
259 const struct nf_conntrack_l3proto *l3proto;
260 const struct nf_conntrack_l4proto *l4proto;
261 unsigned int protoff;
267 l3proto = __nf_ct_l3proto_find(l3num);
268 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
269 if (ret != NF_ACCEPT) {
274 l4proto = __nf_ct_l4proto_find(l3num, protonum);
276 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple,
282 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
285 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
286 const struct nf_conntrack_tuple *orig,
287 const struct nf_conntrack_l3proto *l3proto,
288 const struct nf_conntrack_l4proto *l4proto)
290 memset(inverse, 0, sizeof(*inverse));
292 inverse->src.l3num = orig->src.l3num;
293 if (l3proto->invert_tuple(inverse, orig) == 0)
296 inverse->dst.dir = !orig->dst.dir;
298 inverse->dst.protonum = orig->dst.protonum;
299 return l4proto->invert_tuple(inverse, orig);
301 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
304 clean_from_lists(struct nf_conn *ct)
306 pr_debug("clean_from_lists(%p)\n", ct);
307 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
308 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
310 /* Destroy all pending expectations */
311 nf_ct_remove_expectations(ct);
314 /* must be called with local_bh_disable */
315 static void nf_ct_add_to_dying_list(struct nf_conn *ct)
317 struct ct_pcpu *pcpu;
319 /* add this conntrack to the (per cpu) dying list */
320 ct->cpu = smp_processor_id();
321 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
323 spin_lock(&pcpu->lock);
324 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
326 spin_unlock(&pcpu->lock);
329 /* must be called with local_bh_disable */
330 static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct)
332 struct ct_pcpu *pcpu;
334 /* add this conntrack to the (per cpu) unconfirmed list */
335 ct->cpu = smp_processor_id();
336 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
338 spin_lock(&pcpu->lock);
339 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
341 spin_unlock(&pcpu->lock);
344 /* must be called with local_bh_disable */
345 static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct)
347 struct ct_pcpu *pcpu;
349 /* We overload first tuple to link into unconfirmed or dying list.*/
350 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
352 spin_lock(&pcpu->lock);
353 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
354 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
355 spin_unlock(&pcpu->lock);
358 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
360 /* Released via destroy_conntrack() */
361 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
362 const struct nf_conntrack_zone *zone,
365 struct nf_conn *tmpl, *p;
367 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) {
368 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags);
373 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
375 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
376 tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p;
379 tmpl = kzalloc(sizeof(*tmpl), flags);
384 tmpl->status = IPS_TEMPLATE;
385 write_pnet(&tmpl->ct_net, net);
386 nf_ct_zone_add(tmpl, zone);
387 atomic_set(&tmpl->ct_general.use, 0);
391 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
393 void nf_ct_tmpl_free(struct nf_conn *tmpl)
395 nf_ct_ext_destroy(tmpl);
396 nf_ct_ext_free(tmpl);
398 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
399 kfree((char *)tmpl - tmpl->proto.tmpl_padto);
403 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free);
406 destroy_conntrack(struct nf_conntrack *nfct)
408 struct nf_conn *ct = (struct nf_conn *)nfct;
409 const struct nf_conntrack_l4proto *l4proto;
411 pr_debug("destroy_conntrack(%p)\n", ct);
412 WARN_ON(atomic_read(&nfct->use) != 0);
414 if (unlikely(nf_ct_is_template(ct))) {
418 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
419 if (l4proto->destroy)
420 l4proto->destroy(ct);
423 /* Expectations will have been removed in clean_from_lists,
424 * except TFTP can create an expectation on the first packet,
425 * before connection is in the list, so we need to clean here,
428 nf_ct_remove_expectations(ct);
430 nf_ct_del_from_dying_or_unconfirmed_list(ct);
435 nf_ct_put(ct->master);
437 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
438 nf_conntrack_free(ct);
441 static void nf_ct_delete_from_lists(struct nf_conn *ct)
443 struct net *net = nf_ct_net(ct);
444 unsigned int hash, reply_hash;
445 unsigned int sequence;
447 nf_ct_helper_destroy(ct);
451 sequence = read_seqcount_begin(&nf_conntrack_generation);
452 hash = hash_conntrack(net,
453 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
454 reply_hash = hash_conntrack(net,
455 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
456 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
458 clean_from_lists(ct);
459 nf_conntrack_double_unlock(hash, reply_hash);
461 nf_ct_add_to_dying_list(ct);
466 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
468 struct nf_conn_tstamp *tstamp;
470 if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
473 tstamp = nf_conn_tstamp_find(ct);
474 if (tstamp && tstamp->stop == 0)
475 tstamp->stop = ktime_get_real_ns();
477 if (nf_conntrack_event_report(IPCT_DESTROY, ct,
478 portid, report) < 0) {
479 /* destroy event was not delivered. nf_ct_put will
480 * be done by event cache worker on redelivery.
482 nf_ct_delete_from_lists(ct);
483 nf_conntrack_ecache_delayed_work(nf_ct_net(ct));
487 nf_conntrack_ecache_work(nf_ct_net(ct));
488 nf_ct_delete_from_lists(ct);
492 EXPORT_SYMBOL_GPL(nf_ct_delete);
495 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
496 const struct nf_conntrack_tuple *tuple,
497 const struct nf_conntrack_zone *zone,
498 const struct net *net)
500 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
502 /* A conntrack can be recreated with the equal tuple,
503 * so we need to check that the conntrack is confirmed
505 return nf_ct_tuple_equal(tuple, &h->tuple) &&
506 nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
507 nf_ct_is_confirmed(ct) &&
508 net_eq(net, nf_ct_net(ct));
511 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
512 static void nf_ct_gc_expired(struct nf_conn *ct)
514 if (!atomic_inc_not_zero(&ct->ct_general.use))
517 if (nf_ct_should_gc(ct))
525 * - Caller must take a reference on returned object
526 * and recheck nf_ct_tuple_equal(tuple, &h->tuple)
528 static struct nf_conntrack_tuple_hash *
529 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
530 const struct nf_conntrack_tuple *tuple, u32 hash)
532 struct nf_conntrack_tuple_hash *h;
533 struct hlist_nulls_head *ct_hash;
534 struct hlist_nulls_node *n;
535 unsigned int bucket, hsize;
538 nf_conntrack_get_ht(&ct_hash, &hsize);
539 bucket = reciprocal_scale(hash, hsize);
541 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
544 ct = nf_ct_tuplehash_to_ctrack(h);
545 if (nf_ct_is_expired(ct)) {
546 nf_ct_gc_expired(ct);
550 if (nf_ct_is_dying(ct))
553 if (nf_ct_key_equal(h, tuple, zone, net))
557 * if the nulls value we got at the end of this lookup is
558 * not the expected one, we must restart lookup.
559 * We probably met an item that was moved to another chain.
561 if (get_nulls_value(n) != bucket) {
562 NF_CT_STAT_INC_ATOMIC(net, search_restart);
569 /* Find a connection corresponding to a tuple. */
570 static struct nf_conntrack_tuple_hash *
571 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
572 const struct nf_conntrack_tuple *tuple, u32 hash)
574 struct nf_conntrack_tuple_hash *h;
579 h = ____nf_conntrack_find(net, zone, tuple, hash);
581 ct = nf_ct_tuplehash_to_ctrack(h);
582 if (unlikely(nf_ct_is_dying(ct) ||
583 !atomic_inc_not_zero(&ct->ct_general.use)))
586 if (unlikely(!nf_ct_key_equal(h, tuple, zone, net))) {
597 struct nf_conntrack_tuple_hash *
598 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
599 const struct nf_conntrack_tuple *tuple)
601 return __nf_conntrack_find_get(net, zone, tuple,
602 hash_conntrack_raw(tuple, net));
604 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
606 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
608 unsigned int reply_hash)
610 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
611 &nf_conntrack_hash[hash]);
612 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
613 &nf_conntrack_hash[reply_hash]);
617 nf_conntrack_hash_check_insert(struct nf_conn *ct)
619 const struct nf_conntrack_zone *zone;
620 struct net *net = nf_ct_net(ct);
621 unsigned int hash, reply_hash;
622 struct nf_conntrack_tuple_hash *h;
623 struct hlist_nulls_node *n;
624 unsigned int sequence;
626 zone = nf_ct_zone(ct);
630 sequence = read_seqcount_begin(&nf_conntrack_generation);
631 hash = hash_conntrack(net,
632 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
633 reply_hash = hash_conntrack(net,
634 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
635 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
637 /* See if there's one in the list already, including reverse */
638 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
639 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
643 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
644 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
649 /* The caller holds a reference to this object */
650 atomic_set(&ct->ct_general.use, 2);
651 __nf_conntrack_hash_insert(ct, hash, reply_hash);
652 nf_conntrack_double_unlock(hash, reply_hash);
653 NF_CT_STAT_INC(net, insert);
658 nf_conntrack_double_unlock(hash, reply_hash);
659 NF_CT_STAT_INC(net, insert_failed);
663 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
665 static inline void nf_ct_acct_update(struct nf_conn *ct,
666 enum ip_conntrack_info ctinfo,
669 struct nf_conn_acct *acct;
671 acct = nf_conn_acct_find(ct);
673 struct nf_conn_counter *counter = acct->counter;
675 atomic64_inc(&counter[CTINFO2DIR(ctinfo)].packets);
676 atomic64_add(len, &counter[CTINFO2DIR(ctinfo)].bytes);
680 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
681 const struct nf_conn *loser_ct)
683 struct nf_conn_acct *acct;
685 acct = nf_conn_acct_find(loser_ct);
687 struct nf_conn_counter *counter = acct->counter;
690 /* u32 should be fine since we must have seen one packet. */
691 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
692 nf_ct_acct_update(ct, ctinfo, bytes);
696 /* Resolve race on insertion if this protocol allows this. */
697 static int nf_ct_resolve_clash(struct net *net, struct sk_buff *skb,
698 enum ip_conntrack_info ctinfo,
699 struct nf_conntrack_tuple_hash *h)
701 /* This is the conntrack entry already in hashes that won race. */
702 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
703 const struct nf_conntrack_l4proto *l4proto;
705 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
706 if (l4proto->allow_clash &&
707 ((ct->status & IPS_NAT_DONE_MASK) == 0) &&
708 !nf_ct_is_dying(ct) &&
709 atomic_inc_not_zero(&ct->ct_general.use)) {
710 enum ip_conntrack_info oldinfo;
711 struct nf_conn *loser_ct = nf_ct_get(skb, &oldinfo);
713 nf_ct_acct_merge(ct, ctinfo, loser_ct);
714 nf_conntrack_put(&loser_ct->ct_general);
715 nf_ct_set(skb, ct, oldinfo);
718 NF_CT_STAT_INC(net, drop);
722 /* Confirm a connection given skb; places it in hash table */
724 __nf_conntrack_confirm(struct sk_buff *skb)
726 const struct nf_conntrack_zone *zone;
727 unsigned int hash, reply_hash;
728 struct nf_conntrack_tuple_hash *h;
730 struct nf_conn_help *help;
731 struct nf_conn_tstamp *tstamp;
732 struct hlist_nulls_node *n;
733 enum ip_conntrack_info ctinfo;
735 unsigned int sequence;
738 ct = nf_ct_get(skb, &ctinfo);
741 /* ipt_REJECT uses nf_conntrack_attach to attach related
742 ICMP/TCP RST packets in other direction. Actual packet
743 which created connection will be IP_CT_NEW or for an
744 expected connection, IP_CT_RELATED. */
745 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
748 zone = nf_ct_zone(ct);
752 sequence = read_seqcount_begin(&nf_conntrack_generation);
753 /* reuse the hash saved before */
754 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
755 hash = scale_hash(hash);
756 reply_hash = hash_conntrack(net,
757 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
759 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
761 /* We're not in hash table, and we refuse to set up related
762 * connections for unconfirmed conns. But packet copies and
763 * REJECT will give spurious warnings here.
766 /* No external references means no one else could have
769 WARN_ON(nf_ct_is_confirmed(ct));
770 pr_debug("Confirming conntrack %p\n", ct);
771 /* We have to check the DYING flag after unlink to prevent
772 * a race against nf_ct_get_next_corpse() possibly called from
773 * user context, else we insert an already 'dead' hash, blocking
774 * further use of that particular connection -JM.
776 nf_ct_del_from_dying_or_unconfirmed_list(ct);
778 if (unlikely(nf_ct_is_dying(ct))) {
779 nf_ct_add_to_dying_list(ct);
783 /* See if there's one in the list already, including reverse:
784 NAT could have grabbed it without realizing, since we're
785 not in the hash. If there is, we lost race. */
786 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
787 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
791 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
792 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
796 /* Timer relative to confirmation time, not original
797 setting time, otherwise we'd get timer wrap in
798 weird delay cases. */
799 ct->timeout += nfct_time_stamp;
800 atomic_inc(&ct->ct_general.use);
801 ct->status |= IPS_CONFIRMED;
803 /* set conntrack timestamp, if enabled. */
804 tstamp = nf_conn_tstamp_find(ct);
806 if (skb->tstamp == 0)
807 __net_timestamp(skb);
809 tstamp->start = ktime_to_ns(skb->tstamp);
811 /* Since the lookup is lockless, hash insertion must be done after
812 * starting the timer and setting the CONFIRMED bit. The RCU barriers
813 * guarantee that no other CPU can find the conntrack before the above
814 * stores are visible.
816 __nf_conntrack_hash_insert(ct, hash, reply_hash);
817 nf_conntrack_double_unlock(hash, reply_hash);
820 help = nfct_help(ct);
821 if (help && help->helper)
822 nf_conntrack_event_cache(IPCT_HELPER, ct);
824 nf_conntrack_event_cache(master_ct(ct) ?
825 IPCT_RELATED : IPCT_NEW, ct);
829 nf_ct_add_to_dying_list(ct);
830 ret = nf_ct_resolve_clash(net, skb, ctinfo, h);
832 nf_conntrack_double_unlock(hash, reply_hash);
833 NF_CT_STAT_INC(net, insert_failed);
837 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
839 /* Returns true if a connection correspondings to the tuple (required
842 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
843 const struct nf_conn *ignored_conntrack)
845 struct net *net = nf_ct_net(ignored_conntrack);
846 const struct nf_conntrack_zone *zone;
847 struct nf_conntrack_tuple_hash *h;
848 struct hlist_nulls_head *ct_hash;
849 unsigned int hash, hsize;
850 struct hlist_nulls_node *n;
853 zone = nf_ct_zone(ignored_conntrack);
857 nf_conntrack_get_ht(&ct_hash, &hsize);
858 hash = __hash_conntrack(net, tuple, hsize);
860 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
861 ct = nf_ct_tuplehash_to_ctrack(h);
863 if (ct == ignored_conntrack)
866 if (nf_ct_is_expired(ct)) {
867 nf_ct_gc_expired(ct);
871 if (nf_ct_key_equal(h, tuple, zone, net)) {
872 NF_CT_STAT_INC_ATOMIC(net, found);
878 if (get_nulls_value(n) != hash) {
879 NF_CT_STAT_INC_ATOMIC(net, search_restart);
887 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
889 #define NF_CT_EVICTION_RANGE 8
891 /* There's a small race here where we may free a just-assured
892 connection. Too bad: we're in trouble anyway. */
893 static unsigned int early_drop_list(struct net *net,
894 struct hlist_nulls_head *head)
896 struct nf_conntrack_tuple_hash *h;
897 struct hlist_nulls_node *n;
898 unsigned int drops = 0;
901 hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
902 tmp = nf_ct_tuplehash_to_ctrack(h);
904 if (nf_ct_is_expired(tmp)) {
905 nf_ct_gc_expired(tmp);
909 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
910 !net_eq(nf_ct_net(tmp), net) ||
914 if (!atomic_inc_not_zero(&tmp->ct_general.use))
917 /* kill only if still in same netns -- might have moved due to
918 * SLAB_TYPESAFE_BY_RCU rules.
920 * We steal the timer reference. If that fails timer has
921 * already fired or someone else deleted it. Just drop ref
922 * and move to next entry.
924 if (net_eq(nf_ct_net(tmp), net) &&
925 nf_ct_is_confirmed(tmp) &&
926 nf_ct_delete(tmp, 0, 0))
935 static noinline int early_drop(struct net *net, unsigned int _hash)
939 for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
940 struct hlist_nulls_head *ct_hash;
941 unsigned int hash, hsize, drops;
944 nf_conntrack_get_ht(&ct_hash, &hsize);
945 hash = reciprocal_scale(_hash++, hsize);
947 drops = early_drop_list(net, &ct_hash[hash]);
951 NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
959 static bool gc_worker_skip_ct(const struct nf_conn *ct)
961 return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct);
964 static bool gc_worker_can_early_drop(const struct nf_conn *ct)
966 const struct nf_conntrack_l4proto *l4proto;
968 if (!test_bit(IPS_ASSURED_BIT, &ct->status))
971 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
972 if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
978 static void gc_worker(struct work_struct *work)
980 unsigned int min_interval = max(HZ / GC_MAX_BUCKETS_DIV, 1u);
981 unsigned int i, goal, buckets = 0, expired_count = 0;
982 unsigned int nf_conntrack_max95 = 0;
983 struct conntrack_gc_work *gc_work;
984 unsigned int ratio, scanned = 0;
985 unsigned long next_run;
987 gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
989 goal = nf_conntrack_htable_size / GC_MAX_BUCKETS_DIV;
990 i = gc_work->last_bucket;
991 if (gc_work->early_drop)
992 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u;
995 struct nf_conntrack_tuple_hash *h;
996 struct hlist_nulls_head *ct_hash;
997 struct hlist_nulls_node *n;
1004 nf_conntrack_get_ht(&ct_hash, &hashsz);
1008 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
1011 tmp = nf_ct_tuplehash_to_ctrack(h);
1014 if (nf_ct_is_expired(tmp)) {
1015 nf_ct_gc_expired(tmp);
1020 if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp))
1023 net = nf_ct_net(tmp);
1024 if (atomic_read(&net->ct.count) < nf_conntrack_max95)
1027 /* need to take reference to avoid possible races */
1028 if (!atomic_inc_not_zero(&tmp->ct_general.use))
1031 if (gc_worker_skip_ct(tmp)) {
1036 if (gc_worker_can_early_drop(tmp))
1042 /* could check get_nulls_value() here and restart if ct
1043 * was moved to another chain. But given gc is best-effort
1044 * we will just continue with next hash slot.
1047 cond_resched_rcu_qs();
1048 } while (++buckets < goal);
1050 if (gc_work->exiting)
1054 * Eviction will normally happen from the packet path, and not
1055 * from this gc worker.
1057 * This worker is only here to reap expired entries when system went
1058 * idle after a busy period.
1060 * The heuristics below are supposed to balance conflicting goals:
1062 * 1. Minimize time until we notice a stale entry
1063 * 2. Maximize scan intervals to not waste cycles
1065 * Normally, expire ratio will be close to 0.
1067 * As soon as a sizeable fraction of the entries have expired
1068 * increase scan frequency.
1070 ratio = scanned ? expired_count * 100 / scanned : 0;
1071 if (ratio > GC_EVICT_RATIO) {
1072 gc_work->next_gc_run = min_interval;
1074 unsigned int max = GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV;
1076 BUILD_BUG_ON((GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV) == 0);
1078 gc_work->next_gc_run += min_interval;
1079 if (gc_work->next_gc_run > max)
1080 gc_work->next_gc_run = max;
1083 next_run = gc_work->next_gc_run;
1084 gc_work->last_bucket = i;
1085 gc_work->early_drop = false;
1086 queue_delayed_work(system_long_wq, &gc_work->dwork, next_run);
1089 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1091 INIT_DEFERRABLE_WORK(&gc_work->dwork, gc_worker);
1092 gc_work->next_gc_run = HZ;
1093 gc_work->exiting = false;
1096 static struct nf_conn *
1097 __nf_conntrack_alloc(struct net *net,
1098 const struct nf_conntrack_zone *zone,
1099 const struct nf_conntrack_tuple *orig,
1100 const struct nf_conntrack_tuple *repl,
1101 gfp_t gfp, u32 hash)
1105 /* We don't want any race condition at early drop stage */
1106 atomic_inc(&net->ct.count);
1108 if (nf_conntrack_max &&
1109 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
1110 if (!early_drop(net, hash)) {
1111 if (!conntrack_gc_work.early_drop)
1112 conntrack_gc_work.early_drop = true;
1113 atomic_dec(&net->ct.count);
1114 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1115 return ERR_PTR(-ENOMEM);
1120 * Do not use kmem_cache_zalloc(), as this cache uses
1121 * SLAB_TYPESAFE_BY_RCU.
1123 ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1127 spin_lock_init(&ct->lock);
1128 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1129 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1130 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1131 /* save hash for reusing when confirming */
1132 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1134 write_pnet(&ct->ct_net, net);
1135 memset(&ct->__nfct_init_offset[0], 0,
1136 offsetof(struct nf_conn, proto) -
1137 offsetof(struct nf_conn, __nfct_init_offset[0]));
1139 nf_ct_zone_add(ct, zone);
1141 /* Because we use RCU lookups, we set ct_general.use to zero before
1142 * this is inserted in any list.
1144 atomic_set(&ct->ct_general.use, 0);
1147 atomic_dec(&net->ct.count);
1148 return ERR_PTR(-ENOMEM);
1151 struct nf_conn *nf_conntrack_alloc(struct net *net,
1152 const struct nf_conntrack_zone *zone,
1153 const struct nf_conntrack_tuple *orig,
1154 const struct nf_conntrack_tuple *repl,
1157 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1159 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1161 void nf_conntrack_free(struct nf_conn *ct)
1163 struct net *net = nf_ct_net(ct);
1165 /* A freed object has refcnt == 0, that's
1166 * the golden rule for SLAB_TYPESAFE_BY_RCU
1168 WARN_ON(atomic_read(&ct->ct_general.use) != 0);
1170 nf_ct_ext_destroy(ct);
1172 kmem_cache_free(nf_conntrack_cachep, ct);
1173 smp_mb__before_atomic();
1174 atomic_dec(&net->ct.count);
1176 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1179 /* Allocate a new conntrack: we return -ENOMEM if classification
1180 failed due to stress. Otherwise it really is unclassifiable. */
1181 static noinline struct nf_conntrack_tuple_hash *
1182 init_conntrack(struct net *net, struct nf_conn *tmpl,
1183 const struct nf_conntrack_tuple *tuple,
1184 const struct nf_conntrack_l3proto *l3proto,
1185 const struct nf_conntrack_l4proto *l4proto,
1186 struct sk_buff *skb,
1187 unsigned int dataoff, u32 hash)
1190 struct nf_conn_help *help;
1191 struct nf_conntrack_tuple repl_tuple;
1192 struct nf_conntrack_ecache *ecache;
1193 struct nf_conntrack_expect *exp = NULL;
1194 const struct nf_conntrack_zone *zone;
1195 struct nf_conn_timeout *timeout_ext;
1196 struct nf_conntrack_zone tmp;
1197 unsigned int *timeouts;
1199 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
1200 pr_debug("Can't invert tuple.\n");
1204 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1205 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1208 return (struct nf_conntrack_tuple_hash *)ct;
1210 if (!nf_ct_add_synproxy(ct, tmpl)) {
1211 nf_conntrack_free(ct);
1212 return ERR_PTR(-ENOMEM);
1215 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1217 timeouts = nf_ct_timeout_data(timeout_ext);
1218 if (unlikely(!timeouts))
1219 timeouts = l4proto->get_timeouts(net);
1221 timeouts = l4proto->get_timeouts(net);
1224 if (!l4proto->new(ct, skb, dataoff, timeouts)) {
1225 nf_conntrack_free(ct);
1226 pr_debug("can't track with proto module\n");
1231 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1234 nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1235 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1236 nf_ct_labels_ext_add(ct);
1238 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1239 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1240 ecache ? ecache->expmask : 0,
1244 if (net->ct.expect_count) {
1245 spin_lock(&nf_conntrack_expect_lock);
1246 exp = nf_ct_find_expectation(net, zone, tuple);
1248 pr_debug("expectation arrives ct=%p exp=%p\n",
1250 /* Welcome, Mr. Bond. We've been expecting you... */
1251 __set_bit(IPS_EXPECTED_BIT, &ct->status);
1252 /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1253 ct->master = exp->master;
1255 help = nf_ct_helper_ext_add(ct, exp->helper,
1258 rcu_assign_pointer(help->helper, exp->helper);
1261 #ifdef CONFIG_NF_CONNTRACK_MARK
1262 ct->mark = exp->master->mark;
1264 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1265 ct->secmark = exp->master->secmark;
1267 NF_CT_STAT_INC(net, expect_new);
1269 spin_unlock(&nf_conntrack_expect_lock);
1272 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
1274 /* Now it is inserted into the unconfirmed list, bump refcount */
1275 nf_conntrack_get(&ct->ct_general);
1276 nf_ct_add_to_unconfirmed_list(ct);
1282 exp->expectfn(ct, exp);
1283 nf_ct_expect_put(exp);
1286 return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1289 /* On success, returns 0, sets skb->_nfct | ctinfo */
1291 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
1292 struct sk_buff *skb,
1293 unsigned int dataoff,
1296 const struct nf_conntrack_l3proto *l3proto,
1297 const struct nf_conntrack_l4proto *l4proto)
1299 const struct nf_conntrack_zone *zone;
1300 struct nf_conntrack_tuple tuple;
1301 struct nf_conntrack_tuple_hash *h;
1302 enum ip_conntrack_info ctinfo;
1303 struct nf_conntrack_zone tmp;
1307 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1308 dataoff, l3num, protonum, net, &tuple, l3proto,
1310 pr_debug("Can't get tuple\n");
1314 /* look for tuple match */
1315 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1316 hash = hash_conntrack_raw(&tuple, net);
1317 h = __nf_conntrack_find_get(net, zone, &tuple, hash);
1319 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
1320 skb, dataoff, hash);
1326 ct = nf_ct_tuplehash_to_ctrack(h);
1328 /* It exists; we have (non-exclusive) reference. */
1329 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1330 ctinfo = IP_CT_ESTABLISHED_REPLY;
1332 /* Once we've had two way comms, always ESTABLISHED. */
1333 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1334 pr_debug("normal packet for %p\n", ct);
1335 ctinfo = IP_CT_ESTABLISHED;
1336 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1337 pr_debug("related packet for %p\n", ct);
1338 ctinfo = IP_CT_RELATED;
1340 pr_debug("new packet for %p\n", ct);
1344 nf_ct_set(skb, ct, ctinfo);
1349 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
1350 struct sk_buff *skb)
1352 const struct nf_conntrack_l3proto *l3proto;
1353 const struct nf_conntrack_l4proto *l4proto;
1354 struct nf_conn *ct, *tmpl;
1355 enum ip_conntrack_info ctinfo;
1356 unsigned int *timeouts;
1357 unsigned int dataoff;
1361 tmpl = nf_ct_get(skb, &ctinfo);
1362 if (tmpl || ctinfo == IP_CT_UNTRACKED) {
1363 /* Previously seen (loopback or untracked)? Ignore. */
1364 if ((tmpl && !nf_ct_is_template(tmpl)) ||
1365 ctinfo == IP_CT_UNTRACKED) {
1366 NF_CT_STAT_INC_ATOMIC(net, ignore);
1372 /* rcu_read_lock()ed by nf_hook_thresh */
1373 l3proto = __nf_ct_l3proto_find(pf);
1374 ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
1375 &dataoff, &protonum);
1377 pr_debug("not prepared to track yet or error occurred\n");
1378 NF_CT_STAT_INC_ATOMIC(net, error);
1379 NF_CT_STAT_INC_ATOMIC(net, invalid);
1384 l4proto = __nf_ct_l4proto_find(pf, protonum);
1386 /* It may be an special packet, error, unclean...
1387 * inverse of the return code tells to the netfilter
1388 * core what to do with the packet. */
1389 if (l4proto->error != NULL) {
1390 ret = l4proto->error(net, tmpl, skb, dataoff, pf, hooknum);
1392 NF_CT_STAT_INC_ATOMIC(net, error);
1393 NF_CT_STAT_INC_ATOMIC(net, invalid);
1397 /* ICMP[v6] protocol trackers may assign one conntrack. */
1402 ret = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
1405 /* Too stressed to deal. */
1406 NF_CT_STAT_INC_ATOMIC(net, drop);
1411 ct = nf_ct_get(skb, &ctinfo);
1413 /* Not valid part of a connection */
1414 NF_CT_STAT_INC_ATOMIC(net, invalid);
1419 /* Decide what timeout policy we want to apply to this flow. */
1420 timeouts = nf_ct_timeout_lookup(net, ct, l4proto);
1422 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, timeouts);
1424 /* Invalid: inverse of the return code tells
1425 * the netfilter core what to do */
1426 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1427 nf_conntrack_put(&ct->ct_general);
1429 NF_CT_STAT_INC_ATOMIC(net, invalid);
1430 if (ret == -NF_DROP)
1431 NF_CT_STAT_INC_ATOMIC(net, drop);
1432 /* Special case: TCP tracker reports an attempt to reopen a
1433 * closed/aborted connection. We have to go back and create a
1436 if (ret == -NF_REPEAT)
1442 if (ctinfo == IP_CT_ESTABLISHED_REPLY &&
1443 !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1444 nf_conntrack_event_cache(IPCT_REPLY, ct);
1451 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1453 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
1454 const struct nf_conntrack_tuple *orig)
1459 ret = nf_ct_invert_tuple(inverse, orig,
1460 __nf_ct_l3proto_find(orig->src.l3num),
1461 __nf_ct_l4proto_find(orig->src.l3num,
1462 orig->dst.protonum));
1466 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
1468 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
1469 implicitly racy: see __nf_conntrack_confirm */
1470 void nf_conntrack_alter_reply(struct nf_conn *ct,
1471 const struct nf_conntrack_tuple *newreply)
1473 struct nf_conn_help *help = nfct_help(ct);
1475 /* Should be unconfirmed, so not in hash table yet */
1476 WARN_ON(nf_ct_is_confirmed(ct));
1478 pr_debug("Altering reply tuple of %p to ", ct);
1479 nf_ct_dump_tuple(newreply);
1481 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1482 if (ct->master || (help && !hlist_empty(&help->expectations)))
1486 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1489 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1491 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1492 void __nf_ct_refresh_acct(struct nf_conn *ct,
1493 enum ip_conntrack_info ctinfo,
1494 const struct sk_buff *skb,
1495 unsigned long extra_jiffies,
1500 /* Only update if this is not a fixed timeout */
1501 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1504 /* If not in hash table, timer will not be active yet */
1505 if (nf_ct_is_confirmed(ct))
1506 extra_jiffies += nfct_time_stamp;
1508 ct->timeout = extra_jiffies;
1511 nf_ct_acct_update(ct, ctinfo, skb->len);
1513 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1515 bool nf_ct_kill_acct(struct nf_conn *ct,
1516 enum ip_conntrack_info ctinfo,
1517 const struct sk_buff *skb)
1519 nf_ct_acct_update(ct, ctinfo, skb->len);
1521 return nf_ct_delete(ct, 0, 0);
1523 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
1525 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1527 #include <linux/netfilter/nfnetlink.h>
1528 #include <linux/netfilter/nfnetlink_conntrack.h>
1529 #include <linux/mutex.h>
1531 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
1532 * in ip_conntrack_core, since we don't want the protocols to autoload
1533 * or depend on ctnetlink */
1534 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1535 const struct nf_conntrack_tuple *tuple)
1537 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1538 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1539 goto nla_put_failure;
1545 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1547 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1548 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
1549 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
1551 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1553 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1554 struct nf_conntrack_tuple *t)
1556 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1559 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1560 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1564 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1566 int nf_ct_port_nlattr_tuple_size(void)
1568 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1570 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1573 /* Used by ipt_REJECT and ip6t_REJECT. */
1574 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
1577 enum ip_conntrack_info ctinfo;
1579 /* This ICMP is in reverse direction to the packet which caused it */
1580 ct = nf_ct_get(skb, &ctinfo);
1581 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1582 ctinfo = IP_CT_RELATED_REPLY;
1584 ctinfo = IP_CT_RELATED;
1586 /* Attach to new skbuff, and increment count */
1587 nf_ct_set(nskb, ct, ctinfo);
1588 nf_conntrack_get(skb_nfct(nskb));
1591 /* Bring out ya dead! */
1592 static struct nf_conn *
1593 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
1594 void *data, unsigned int *bucket)
1596 struct nf_conntrack_tuple_hash *h;
1598 struct hlist_nulls_node *n;
1601 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1602 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
1604 nf_conntrack_lock(lockp);
1605 if (*bucket < nf_conntrack_htable_size) {
1606 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnnode) {
1607 if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
1609 ct = nf_ct_tuplehash_to_ctrack(h);
1621 atomic_inc(&ct->ct_general.use);
1627 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data),
1628 void *data, u32 portid, int report)
1630 unsigned int bucket = 0, sequence;
1636 sequence = read_seqcount_begin(&nf_conntrack_generation);
1638 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1639 /* Time to push up daises... */
1641 nf_ct_delete(ct, portid, report);
1646 if (!read_seqcount_retry(&nf_conntrack_generation, sequence))
1653 int (*iter)(struct nf_conn *i, void *data);
1658 static int iter_net_only(struct nf_conn *i, void *data)
1660 struct iter_data *d = data;
1662 if (!net_eq(d->net, nf_ct_net(i)))
1665 return d->iter(i, d->data);
1669 __nf_ct_unconfirmed_destroy(struct net *net)
1673 for_each_possible_cpu(cpu) {
1674 struct nf_conntrack_tuple_hash *h;
1675 struct hlist_nulls_node *n;
1676 struct ct_pcpu *pcpu;
1678 pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
1680 spin_lock_bh(&pcpu->lock);
1681 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
1684 ct = nf_ct_tuplehash_to_ctrack(h);
1686 /* we cannot call iter() on unconfirmed list, the
1687 * owning cpu can reallocate ct->ext at any time.
1689 set_bit(IPS_DYING_BIT, &ct->status);
1691 spin_unlock_bh(&pcpu->lock);
1696 void nf_ct_unconfirmed_destroy(struct net *net)
1700 if (atomic_read(&net->ct.count) > 0) {
1701 __nf_ct_unconfirmed_destroy(net);
1702 nf_queue_nf_hook_drop(net);
1706 EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy);
1708 void nf_ct_iterate_cleanup_net(struct net *net,
1709 int (*iter)(struct nf_conn *i, void *data),
1710 void *data, u32 portid, int report)
1716 if (atomic_read(&net->ct.count) == 0)
1723 nf_ct_iterate_cleanup(iter_net_only, &d, portid, report);
1725 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net);
1728 * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table
1729 * @iter: callback to invoke for each conntrack
1730 * @data: data to pass to @iter
1732 * Like nf_ct_iterate_cleanup, but first marks conntracks on the
1733 * unconfirmed list as dying (so they will not be inserted into
1736 * Can only be called in module exit path.
1739 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
1745 if (atomic_read(&net->ct.count) == 0)
1747 __nf_ct_unconfirmed_destroy(net);
1748 nf_queue_nf_hook_drop(net);
1752 /* Need to wait for netns cleanup worker to finish, if its
1753 * running -- it might have deleted a net namespace from
1754 * the global list, so our __nf_ct_unconfirmed_destroy() might
1755 * not have affected all namespaces.
1759 /* a conntrack could have been unlinked from unconfirmed list
1760 * before we grabbed pcpu lock in __nf_ct_unconfirmed_destroy().
1761 * This makes sure its inserted into conntrack table.
1765 nf_ct_iterate_cleanup(iter, data, 0, 0);
1767 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy);
1769 static int kill_all(struct nf_conn *i, void *data)
1771 return net_eq(nf_ct_net(i), data);
1774 void nf_ct_free_hashtable(void *hash, unsigned int size)
1776 if (is_vmalloc_addr(hash))
1779 free_pages((unsigned long)hash,
1780 get_order(sizeof(struct hlist_head) * size));
1782 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1784 void nf_conntrack_cleanup_start(void)
1786 conntrack_gc_work.exiting = true;
1787 RCU_INIT_POINTER(ip_ct_attach, NULL);
1790 void nf_conntrack_cleanup_end(void)
1792 RCU_INIT_POINTER(nf_ct_destroy, NULL);
1794 cancel_delayed_work_sync(&conntrack_gc_work.dwork);
1795 nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_htable_size);
1797 nf_conntrack_proto_fini();
1798 nf_conntrack_seqadj_fini();
1799 nf_conntrack_labels_fini();
1800 nf_conntrack_helper_fini();
1801 nf_conntrack_timeout_fini();
1802 nf_conntrack_ecache_fini();
1803 nf_conntrack_tstamp_fini();
1804 nf_conntrack_acct_fini();
1805 nf_conntrack_expect_fini();
1807 kmem_cache_destroy(nf_conntrack_cachep);
1811 * Mishearing the voices in his head, our hero wonders how he's
1812 * supposed to kill the mall.
1814 void nf_conntrack_cleanup_net(struct net *net)
1818 list_add(&net->exit_list, &single);
1819 nf_conntrack_cleanup_net_list(&single);
1822 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
1828 * This makes sure all current packets have passed through
1829 * netfilter framework. Roll on, two-stage module
1835 list_for_each_entry(net, net_exit_list, exit_list) {
1836 nf_ct_iterate_cleanup(kill_all, net, 0, 0);
1837 if (atomic_read(&net->ct.count) != 0)
1842 goto i_see_dead_people;
1845 list_for_each_entry(net, net_exit_list, exit_list) {
1846 nf_conntrack_proto_pernet_fini(net);
1847 nf_conntrack_helper_pernet_fini(net);
1848 nf_conntrack_ecache_pernet_fini(net);
1849 nf_conntrack_tstamp_pernet_fini(net);
1850 nf_conntrack_acct_pernet_fini(net);
1851 nf_conntrack_expect_pernet_fini(net);
1852 free_percpu(net->ct.stat);
1853 free_percpu(net->ct.pcpu_lists);
1857 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
1859 struct hlist_nulls_head *hash;
1860 unsigned int nr_slots, i;
1863 if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
1866 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1867 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1869 if (nr_slots > (UINT_MAX / sizeof(struct hlist_nulls_head)))
1872 sz = nr_slots * sizeof(struct hlist_nulls_head);
1873 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1879 for (i = 0; i < nr_slots; i++)
1880 INIT_HLIST_NULLS_HEAD(&hash[i], i);
1884 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1886 int nf_conntrack_hash_resize(unsigned int hashsize)
1889 unsigned int old_size;
1890 struct hlist_nulls_head *hash, *old_hash;
1891 struct nf_conntrack_tuple_hash *h;
1897 hash = nf_ct_alloc_hashtable(&hashsize, 1);
1901 old_size = nf_conntrack_htable_size;
1902 if (old_size == hashsize) {
1903 nf_ct_free_hashtable(hash, hashsize);
1908 nf_conntrack_all_lock();
1909 write_seqcount_begin(&nf_conntrack_generation);
1911 /* Lookups in the old hash might happen in parallel, which means we
1912 * might get false negatives during connection lookup. New connections
1913 * created because of a false negative won't make it into the hash
1914 * though since that required taking the locks.
1917 for (i = 0; i < nf_conntrack_htable_size; i++) {
1918 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
1919 h = hlist_nulls_entry(nf_conntrack_hash[i].first,
1920 struct nf_conntrack_tuple_hash, hnnode);
1921 ct = nf_ct_tuplehash_to_ctrack(h);
1922 hlist_nulls_del_rcu(&h->hnnode);
1923 bucket = __hash_conntrack(nf_ct_net(ct),
1924 &h->tuple, hashsize);
1925 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1928 old_size = nf_conntrack_htable_size;
1929 old_hash = nf_conntrack_hash;
1931 nf_conntrack_hash = hash;
1932 nf_conntrack_htable_size = hashsize;
1934 write_seqcount_end(&nf_conntrack_generation);
1935 nf_conntrack_all_unlock();
1939 nf_ct_free_hashtable(old_hash, old_size);
1943 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1945 unsigned int hashsize;
1948 if (current->nsproxy->net_ns != &init_net)
1951 /* On boot, we can set this without any fancy locking. */
1952 if (!nf_conntrack_htable_size)
1953 return param_set_uint(val, kp);
1955 rc = kstrtouint(val, 0, &hashsize);
1959 return nf_conntrack_hash_resize(hashsize);
1961 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1963 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1964 &nf_conntrack_htable_size, 0600);
1966 static __always_inline unsigned int total_extension_size(void)
1968 /* remember to add new extensions below */
1969 BUILD_BUG_ON(NF_CT_EXT_NUM > 9);
1971 return sizeof(struct nf_ct_ext) +
1972 sizeof(struct nf_conn_help)
1973 #if IS_ENABLED(CONFIG_NF_NAT)
1974 + sizeof(struct nf_conn_nat)
1976 + sizeof(struct nf_conn_seqadj)
1977 + sizeof(struct nf_conn_acct)
1978 #ifdef CONFIG_NF_CONNTRACK_EVENTS
1979 + sizeof(struct nf_conntrack_ecache)
1981 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
1982 + sizeof(struct nf_conn_tstamp)
1984 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
1985 + sizeof(struct nf_conn_timeout)
1987 #ifdef CONFIG_NF_CONNTRACK_LABELS
1988 + sizeof(struct nf_conn_labels)
1990 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
1991 + sizeof(struct nf_conn_synproxy)
1996 int nf_conntrack_init_start(void)
2002 /* struct nf_ct_ext uses u8 to store offsets/size */
2003 BUILD_BUG_ON(total_extension_size() > 255u);
2005 seqcount_init(&nf_conntrack_generation);
2007 for (i = 0; i < CONNTRACK_LOCKS; i++)
2008 spin_lock_init(&nf_conntrack_locks[i]);
2010 if (!nf_conntrack_htable_size) {
2011 /* Idea from tcp.c: use 1/16384 of memory.
2012 * On i386: 32MB machine has 512 buckets.
2013 * >= 1GB machines have 16384 buckets.
2014 * >= 4GB machines have 65536 buckets.
2016 nf_conntrack_htable_size
2017 = (((totalram_pages << PAGE_SHIFT) / 16384)
2018 / sizeof(struct hlist_head));
2019 if (totalram_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
2020 nf_conntrack_htable_size = 65536;
2021 else if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
2022 nf_conntrack_htable_size = 16384;
2023 if (nf_conntrack_htable_size < 32)
2024 nf_conntrack_htable_size = 32;
2026 /* Use a max. factor of four by default to get the same max as
2027 * with the old struct list_heads. When a table size is given
2028 * we use the old value of 8 to avoid reducing the max.
2033 nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
2034 if (!nf_conntrack_hash)
2037 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
2039 nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
2040 sizeof(struct nf_conn),
2042 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
2043 if (!nf_conntrack_cachep)
2046 printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
2047 NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
2050 ret = nf_conntrack_expect_init();
2054 ret = nf_conntrack_acct_init();
2058 ret = nf_conntrack_tstamp_init();
2062 ret = nf_conntrack_ecache_init();
2066 ret = nf_conntrack_timeout_init();
2070 ret = nf_conntrack_helper_init();
2074 ret = nf_conntrack_labels_init();
2078 ret = nf_conntrack_seqadj_init();
2082 ret = nf_conntrack_proto_init();
2086 conntrack_gc_work_init(&conntrack_gc_work);
2087 queue_delayed_work(system_long_wq, &conntrack_gc_work.dwork, HZ);
2092 nf_conntrack_seqadj_fini();
2094 nf_conntrack_labels_fini();
2096 nf_conntrack_helper_fini();
2098 nf_conntrack_timeout_fini();
2100 nf_conntrack_ecache_fini();
2102 nf_conntrack_tstamp_fini();
2104 nf_conntrack_acct_fini();
2106 nf_conntrack_expect_fini();
2108 kmem_cache_destroy(nf_conntrack_cachep);
2110 nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_htable_size);
2114 void nf_conntrack_init_end(void)
2116 /* For use by REJECT target */
2117 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
2118 RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
2122 * We need to use special "null" values, not used in hash table
2124 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0)
2125 #define DYING_NULLS_VAL ((1<<30)+1)
2126 #define TEMPLATE_NULLS_VAL ((1<<30)+2)
2128 int nf_conntrack_init_net(struct net *net)
2133 BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER);
2134 atomic_set(&net->ct.count, 0);
2136 net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
2137 if (!net->ct.pcpu_lists)
2140 for_each_possible_cpu(cpu) {
2141 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2143 spin_lock_init(&pcpu->lock);
2144 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
2145 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
2148 net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
2150 goto err_pcpu_lists;
2152 ret = nf_conntrack_expect_pernet_init(net);
2155 ret = nf_conntrack_acct_pernet_init(net);
2158 ret = nf_conntrack_tstamp_pernet_init(net);
2161 ret = nf_conntrack_ecache_pernet_init(net);
2164 ret = nf_conntrack_helper_pernet_init(net);
2167 ret = nf_conntrack_proto_pernet_init(net);
2173 nf_conntrack_helper_pernet_fini(net);
2175 nf_conntrack_ecache_pernet_fini(net);
2177 nf_conntrack_tstamp_pernet_fini(net);
2179 nf_conntrack_acct_pernet_fini(net);
2181 nf_conntrack_expect_pernet_fini(net);
2183 free_percpu(net->ct.stat);
2185 free_percpu(net->ct.pcpu_lists);