1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Connection state tracking for netfilter. This is separated from,
3 but required by, the NAT layer; it can also be used by an iptables
6 /* (C) 1999-2001 Paul `Rusty' Russell
7 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
8 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
9 * (C) 2005-2012 Patrick McHardy <kaber@trash.net>
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #include <linux/types.h>
15 #include <linux/netfilter.h>
16 #include <linux/module.h>
17 #include <linux/sched.h>
18 #include <linux/skbuff.h>
19 #include <linux/proc_fs.h>
20 #include <linux/vmalloc.h>
21 #include <linux/stddef.h>
22 #include <linux/slab.h>
23 #include <linux/random.h>
24 #include <linux/jhash.h>
25 #include <linux/siphash.h>
26 #include <linux/err.h>
27 #include <linux/percpu.h>
28 #include <linux/moduleparam.h>
29 #include <linux/notifier.h>
30 #include <linux/kernel.h>
31 #include <linux/netdevice.h>
32 #include <linux/socket.h>
34 #include <linux/nsproxy.h>
35 #include <linux/rculist_nulls.h>
37 #include <net/netfilter/nf_conntrack.h>
38 #include <net/netfilter/nf_conntrack_l4proto.h>
39 #include <net/netfilter/nf_conntrack_expect.h>
40 #include <net/netfilter/nf_conntrack_helper.h>
41 #include <net/netfilter/nf_conntrack_seqadj.h>
42 #include <net/netfilter/nf_conntrack_core.h>
43 #include <net/netfilter/nf_conntrack_extend.h>
44 #include <net/netfilter/nf_conntrack_acct.h>
45 #include <net/netfilter/nf_conntrack_ecache.h>
46 #include <net/netfilter/nf_conntrack_zones.h>
47 #include <net/netfilter/nf_conntrack_timestamp.h>
48 #include <net/netfilter/nf_conntrack_timeout.h>
49 #include <net/netfilter/nf_conntrack_labels.h>
50 #include <net/netfilter/nf_conntrack_synproxy.h>
51 #include <net/netfilter/nf_nat.h>
52 #include <net/netfilter/nf_nat_helper.h>
53 #include <net/netns/hash.h>
56 #include "nf_internals.h"
58 __cacheline_aligned_in_smp spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS];
59 EXPORT_SYMBOL_GPL(nf_conntrack_locks);
61 __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock);
62 EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock);
64 struct hlist_nulls_head *nf_conntrack_hash __read_mostly;
65 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
67 struct conntrack_gc_work {
68 struct delayed_work dwork;
75 static __read_mostly struct kmem_cache *nf_conntrack_cachep;
76 static DEFINE_SPINLOCK(nf_conntrack_locks_all_lock);
77 static __read_mostly bool nf_conntrack_locks_all;
79 /* every gc cycle scans at most 1/GC_MAX_BUCKETS_DIV part of table */
80 #define GC_MAX_BUCKETS_DIV 128u
81 /* upper bound of full table scan */
82 #define GC_MAX_SCAN_JIFFIES (16u * HZ)
83 /* desired ratio of entries found to be expired */
84 #define GC_EVICT_RATIO 50u
86 static struct conntrack_gc_work conntrack_gc_work;
88 void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
90 /* 1) Acquire the lock */
93 /* 2) read nf_conntrack_locks_all, with ACQUIRE semantics
94 * It pairs with the smp_store_release() in nf_conntrack_all_unlock()
96 if (likely(smp_load_acquire(&nf_conntrack_locks_all) == false))
99 /* fast path failed, unlock */
102 /* Slow path 1) get global lock */
103 spin_lock(&nf_conntrack_locks_all_lock);
105 /* Slow path 2) get the lock we want */
108 /* Slow path 3) release the global lock */
109 spin_unlock(&nf_conntrack_locks_all_lock);
111 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
113 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2)
115 h1 %= CONNTRACK_LOCKS;
116 h2 %= CONNTRACK_LOCKS;
117 spin_unlock(&nf_conntrack_locks[h1]);
119 spin_unlock(&nf_conntrack_locks[h2]);
122 /* return true if we need to recompute hashes (in case hash table was resized) */
123 static bool nf_conntrack_double_lock(struct net *net, unsigned int h1,
124 unsigned int h2, unsigned int sequence)
126 h1 %= CONNTRACK_LOCKS;
127 h2 %= CONNTRACK_LOCKS;
129 nf_conntrack_lock(&nf_conntrack_locks[h1]);
131 spin_lock_nested(&nf_conntrack_locks[h2],
132 SINGLE_DEPTH_NESTING);
134 nf_conntrack_lock(&nf_conntrack_locks[h2]);
135 spin_lock_nested(&nf_conntrack_locks[h1],
136 SINGLE_DEPTH_NESTING);
138 if (read_seqcount_retry(&nf_conntrack_generation, sequence)) {
139 nf_conntrack_double_unlock(h1, h2);
145 static void nf_conntrack_all_lock(void)
146 __acquires(&nf_conntrack_locks_all_lock)
150 spin_lock(&nf_conntrack_locks_all_lock);
152 nf_conntrack_locks_all = true;
154 for (i = 0; i < CONNTRACK_LOCKS; i++) {
155 spin_lock(&nf_conntrack_locks[i]);
157 /* This spin_unlock provides the "release" to ensure that
158 * nf_conntrack_locks_all==true is visible to everyone that
159 * acquired spin_lock(&nf_conntrack_locks[]).
161 spin_unlock(&nf_conntrack_locks[i]);
165 static void nf_conntrack_all_unlock(void)
166 __releases(&nf_conntrack_locks_all_lock)
168 /* All prior stores must be complete before we clear
169 * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
170 * might observe the false value but not the entire
172 * It pairs with the smp_load_acquire() in nf_conntrack_lock()
174 smp_store_release(&nf_conntrack_locks_all, false);
175 spin_unlock(&nf_conntrack_locks_all_lock);
178 unsigned int nf_conntrack_htable_size __read_mostly;
179 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
181 unsigned int nf_conntrack_max __read_mostly;
182 EXPORT_SYMBOL_GPL(nf_conntrack_max);
183 seqcount_spinlock_t nf_conntrack_generation __read_mostly;
184 static unsigned int nf_conntrack_hash_rnd __read_mostly;
186 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
187 const struct net *net)
192 get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
194 /* The direction must be ignored, so we hash everything up to the
195 * destination ports (which is a multiple of 4) and treat the last
196 * three bytes manually.
198 seed = nf_conntrack_hash_rnd ^ net_hash_mix(net);
199 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
200 return jhash2((u32 *)tuple, n, seed ^
201 (((__force __u16)tuple->dst.u.all << 16) |
202 tuple->dst.protonum));
205 static u32 scale_hash(u32 hash)
207 return reciprocal_scale(hash, nf_conntrack_htable_size);
210 static u32 __hash_conntrack(const struct net *net,
211 const struct nf_conntrack_tuple *tuple,
214 return reciprocal_scale(hash_conntrack_raw(tuple, net), size);
217 static u32 hash_conntrack(const struct net *net,
218 const struct nf_conntrack_tuple *tuple)
220 return scale_hash(hash_conntrack_raw(tuple, net));
223 static bool nf_ct_get_tuple_ports(const struct sk_buff *skb,
224 unsigned int dataoff,
225 struct nf_conntrack_tuple *tuple)
229 } _inet_hdr, *inet_hdr;
231 /* Actually only need first 4 bytes to get ports. */
232 inet_hdr = skb_header_pointer(skb, dataoff, sizeof(_inet_hdr), &_inet_hdr);
236 tuple->src.u.udp.port = inet_hdr->sport;
237 tuple->dst.u.udp.port = inet_hdr->dport;
242 nf_ct_get_tuple(const struct sk_buff *skb,
244 unsigned int dataoff,
248 struct nf_conntrack_tuple *tuple)
254 memset(tuple, 0, sizeof(*tuple));
256 tuple->src.l3num = l3num;
259 nhoff += offsetof(struct iphdr, saddr);
260 size = 2 * sizeof(__be32);
263 nhoff += offsetof(struct ipv6hdr, saddr);
264 size = sizeof(_addrs);
270 ap = skb_header_pointer(skb, nhoff, size, _addrs);
276 tuple->src.u3.ip = ap[0];
277 tuple->dst.u3.ip = ap[1];
280 memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
281 memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
285 tuple->dst.protonum = protonum;
286 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
289 #if IS_ENABLED(CONFIG_IPV6)
291 return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple);
294 return icmp_pkt_to_tuple(skb, dataoff, net, tuple);
295 #ifdef CONFIG_NF_CT_PROTO_GRE
297 return gre_pkt_to_tuple(skb, dataoff, net, tuple);
300 case IPPROTO_UDP: /* fallthrough */
301 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
302 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
303 case IPPROTO_UDPLITE:
304 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
306 #ifdef CONFIG_NF_CT_PROTO_SCTP
308 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
310 #ifdef CONFIG_NF_CT_PROTO_DCCP
312 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
321 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
325 const struct iphdr *iph;
328 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
332 /* Conntrack defragments packets, we might still see fragments
333 * inside ICMP packets though.
335 if (iph->frag_off & htons(IP_OFFSET))
338 dataoff = nhoff + (iph->ihl << 2);
339 *protonum = iph->protocol;
341 /* Check bogus IP headers */
342 if (dataoff > skb->len) {
343 pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
344 nhoff, iph->ihl << 2, skb->len);
350 #if IS_ENABLED(CONFIG_IPV6)
351 static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
355 unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
359 if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
360 &nexthdr, sizeof(nexthdr)) != 0) {
361 pr_debug("can't get nexthdr\n");
364 protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
366 * (protoff == skb->len) means the packet has not data, just
367 * IPv6 and possibly extensions headers, but it is tracked anyway
369 if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
370 pr_debug("can't find proto in pkt\n");
379 static int get_l4proto(const struct sk_buff *skb,
380 unsigned int nhoff, u8 pf, u8 *l4num)
384 return ipv4_get_l4proto(skb, nhoff, l4num);
385 #if IS_ENABLED(CONFIG_IPV6)
387 return ipv6_get_l4proto(skb, nhoff, l4num);
396 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
398 struct net *net, struct nf_conntrack_tuple *tuple)
403 protoff = get_l4proto(skb, nhoff, l3num, &protonum);
407 return nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple);
409 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
412 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
413 const struct nf_conntrack_tuple *orig)
415 memset(inverse, 0, sizeof(*inverse));
417 inverse->src.l3num = orig->src.l3num;
419 switch (orig->src.l3num) {
421 inverse->src.u3.ip = orig->dst.u3.ip;
422 inverse->dst.u3.ip = orig->src.u3.ip;
425 inverse->src.u3.in6 = orig->dst.u3.in6;
426 inverse->dst.u3.in6 = orig->src.u3.in6;
432 inverse->dst.dir = !orig->dst.dir;
434 inverse->dst.protonum = orig->dst.protonum;
436 switch (orig->dst.protonum) {
438 return nf_conntrack_invert_icmp_tuple(inverse, orig);
439 #if IS_ENABLED(CONFIG_IPV6)
441 return nf_conntrack_invert_icmpv6_tuple(inverse, orig);
445 inverse->src.u.all = orig->dst.u.all;
446 inverse->dst.u.all = orig->src.u.all;
449 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
451 /* Generate a almost-unique pseudo-id for a given conntrack.
453 * intentionally doesn't re-use any of the seeds used for hash
454 * table location, we assume id gets exposed to userspace.
456 * Following nf_conn items do not change throughout lifetime
460 * 2. nf_conn->master address (normally NULL)
461 * 3. the associated net namespace
462 * 4. the original direction tuple
464 u32 nf_ct_get_id(const struct nf_conn *ct)
466 static __read_mostly siphash_key_t ct_id_seed;
467 unsigned long a, b, c, d;
469 net_get_random_once(&ct_id_seed, sizeof(ct_id_seed));
471 a = (unsigned long)ct;
472 b = (unsigned long)ct->master;
473 c = (unsigned long)nf_ct_net(ct);
474 d = (unsigned long)siphash(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
475 sizeof(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple),
478 return siphash_4u64((u64)a, (u64)b, (u64)c, (u64)d, &ct_id_seed);
480 return siphash_4u32((u32)a, (u32)b, (u32)c, (u32)d, &ct_id_seed);
483 EXPORT_SYMBOL_GPL(nf_ct_get_id);
486 clean_from_lists(struct nf_conn *ct)
488 pr_debug("clean_from_lists(%p)\n", ct);
489 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
490 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
492 /* Destroy all pending expectations */
493 nf_ct_remove_expectations(ct);
496 /* must be called with local_bh_disable */
497 static void nf_ct_add_to_dying_list(struct nf_conn *ct)
499 struct ct_pcpu *pcpu;
501 /* add this conntrack to the (per cpu) dying list */
502 ct->cpu = smp_processor_id();
503 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
505 spin_lock(&pcpu->lock);
506 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
508 spin_unlock(&pcpu->lock);
511 /* must be called with local_bh_disable */
512 static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct)
514 struct ct_pcpu *pcpu;
516 /* add this conntrack to the (per cpu) unconfirmed list */
517 ct->cpu = smp_processor_id();
518 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
520 spin_lock(&pcpu->lock);
521 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
523 spin_unlock(&pcpu->lock);
526 /* must be called with local_bh_disable */
527 static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct)
529 struct ct_pcpu *pcpu;
531 /* We overload first tuple to link into unconfirmed or dying list.*/
532 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
534 spin_lock(&pcpu->lock);
535 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
536 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
537 spin_unlock(&pcpu->lock);
540 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
542 /* Released via destroy_conntrack() */
543 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
544 const struct nf_conntrack_zone *zone,
547 struct nf_conn *tmpl, *p;
549 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) {
550 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags);
555 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
557 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
558 tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p;
561 tmpl = kzalloc(sizeof(*tmpl), flags);
566 tmpl->status = IPS_TEMPLATE;
567 write_pnet(&tmpl->ct_net, net);
568 nf_ct_zone_add(tmpl, zone);
569 atomic_set(&tmpl->ct_general.use, 0);
573 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
575 void nf_ct_tmpl_free(struct nf_conn *tmpl)
577 nf_ct_ext_destroy(tmpl);
579 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
580 kfree((char *)tmpl - tmpl->proto.tmpl_padto);
584 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free);
586 static void destroy_gre_conntrack(struct nf_conn *ct)
588 #ifdef CONFIG_NF_CT_PROTO_GRE
589 struct nf_conn *master = ct->master;
592 nf_ct_gre_keymap_destroy(master);
597 destroy_conntrack(struct nf_conntrack *nfct)
599 struct nf_conn *ct = (struct nf_conn *)nfct;
601 pr_debug("destroy_conntrack(%p)\n", ct);
602 WARN_ON(atomic_read(&nfct->use) != 0);
604 if (unlikely(nf_ct_is_template(ct))) {
609 if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE))
610 destroy_gre_conntrack(ct);
613 /* Expectations will have been removed in clean_from_lists,
614 * except TFTP can create an expectation on the first packet,
615 * before connection is in the list, so we need to clean here,
618 nf_ct_remove_expectations(ct);
620 nf_ct_del_from_dying_or_unconfirmed_list(ct);
625 nf_ct_put(ct->master);
627 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
628 nf_conntrack_free(ct);
631 static void nf_ct_delete_from_lists(struct nf_conn *ct)
633 struct net *net = nf_ct_net(ct);
634 unsigned int hash, reply_hash;
635 unsigned int sequence;
637 nf_ct_helper_destroy(ct);
641 sequence = read_seqcount_begin(&nf_conntrack_generation);
642 hash = hash_conntrack(net,
643 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
644 reply_hash = hash_conntrack(net,
645 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
646 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
648 clean_from_lists(ct);
649 nf_conntrack_double_unlock(hash, reply_hash);
651 nf_ct_add_to_dying_list(ct);
656 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
658 struct nf_conn_tstamp *tstamp;
660 if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
663 tstamp = nf_conn_tstamp_find(ct);
664 if (tstamp && tstamp->stop == 0)
665 tstamp->stop = ktime_get_real_ns();
667 if (nf_conntrack_event_report(IPCT_DESTROY, ct,
668 portid, report) < 0) {
669 /* destroy event was not delivered. nf_ct_put will
670 * be done by event cache worker on redelivery.
672 nf_ct_delete_from_lists(ct);
673 nf_conntrack_ecache_delayed_work(nf_ct_net(ct));
677 nf_conntrack_ecache_work(nf_ct_net(ct));
678 nf_ct_delete_from_lists(ct);
682 EXPORT_SYMBOL_GPL(nf_ct_delete);
685 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
686 const struct nf_conntrack_tuple *tuple,
687 const struct nf_conntrack_zone *zone,
688 const struct net *net)
690 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
692 /* A conntrack can be recreated with the equal tuple,
693 * so we need to check that the conntrack is confirmed
695 return nf_ct_tuple_equal(tuple, &h->tuple) &&
696 nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
697 nf_ct_is_confirmed(ct) &&
698 net_eq(net, nf_ct_net(ct));
702 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2)
704 return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
705 &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
706 nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple,
707 &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) &&
708 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) &&
709 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) &&
710 net_eq(nf_ct_net(ct1), nf_ct_net(ct2));
713 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
714 static void nf_ct_gc_expired(struct nf_conn *ct)
716 if (!atomic_inc_not_zero(&ct->ct_general.use))
719 if (nf_ct_should_gc(ct))
727 * - Caller must take a reference on returned object
728 * and recheck nf_ct_tuple_equal(tuple, &h->tuple)
730 static struct nf_conntrack_tuple_hash *
731 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
732 const struct nf_conntrack_tuple *tuple, u32 hash)
734 struct nf_conntrack_tuple_hash *h;
735 struct hlist_nulls_head *ct_hash;
736 struct hlist_nulls_node *n;
737 unsigned int bucket, hsize;
740 nf_conntrack_get_ht(&ct_hash, &hsize);
741 bucket = reciprocal_scale(hash, hsize);
743 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
746 ct = nf_ct_tuplehash_to_ctrack(h);
747 if (nf_ct_is_expired(ct)) {
748 nf_ct_gc_expired(ct);
752 if (nf_ct_key_equal(h, tuple, zone, net))
756 * if the nulls value we got at the end of this lookup is
757 * not the expected one, we must restart lookup.
758 * We probably met an item that was moved to another chain.
760 if (get_nulls_value(n) != bucket) {
761 NF_CT_STAT_INC_ATOMIC(net, search_restart);
768 /* Find a connection corresponding to a tuple. */
769 static struct nf_conntrack_tuple_hash *
770 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
771 const struct nf_conntrack_tuple *tuple, u32 hash)
773 struct nf_conntrack_tuple_hash *h;
778 h = ____nf_conntrack_find(net, zone, tuple, hash);
780 /* We have a candidate that matches the tuple we're interested
781 * in, try to obtain a reference and re-check tuple
783 ct = nf_ct_tuplehash_to_ctrack(h);
784 if (likely(atomic_inc_not_zero(&ct->ct_general.use))) {
785 if (likely(nf_ct_key_equal(h, tuple, zone, net)))
788 /* TYPESAFE_BY_RCU recycled the candidate */
800 struct nf_conntrack_tuple_hash *
801 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
802 const struct nf_conntrack_tuple *tuple)
804 return __nf_conntrack_find_get(net, zone, tuple,
805 hash_conntrack_raw(tuple, net));
807 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
809 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
811 unsigned int reply_hash)
813 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
814 &nf_conntrack_hash[hash]);
815 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
816 &nf_conntrack_hash[reply_hash]);
820 nf_conntrack_hash_check_insert(struct nf_conn *ct)
822 const struct nf_conntrack_zone *zone;
823 struct net *net = nf_ct_net(ct);
824 unsigned int hash, reply_hash;
825 struct nf_conntrack_tuple_hash *h;
826 struct hlist_nulls_node *n;
827 unsigned int sequence;
829 zone = nf_ct_zone(ct);
833 sequence = read_seqcount_begin(&nf_conntrack_generation);
834 hash = hash_conntrack(net,
835 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
836 reply_hash = hash_conntrack(net,
837 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
838 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
840 /* See if there's one in the list already, including reverse */
841 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
842 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
846 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
847 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
852 /* The caller holds a reference to this object */
853 atomic_set(&ct->ct_general.use, 2);
854 __nf_conntrack_hash_insert(ct, hash, reply_hash);
855 nf_conntrack_double_unlock(hash, reply_hash);
856 NF_CT_STAT_INC(net, insert);
861 nf_conntrack_double_unlock(hash, reply_hash);
865 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
867 void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets,
870 struct nf_conn_acct *acct;
872 acct = nf_conn_acct_find(ct);
874 struct nf_conn_counter *counter = acct->counter;
876 atomic64_add(packets, &counter[dir].packets);
877 atomic64_add(bytes, &counter[dir].bytes);
880 EXPORT_SYMBOL_GPL(nf_ct_acct_add);
882 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
883 const struct nf_conn *loser_ct)
885 struct nf_conn_acct *acct;
887 acct = nf_conn_acct_find(loser_ct);
889 struct nf_conn_counter *counter = acct->counter;
892 /* u32 should be fine since we must have seen one packet. */
893 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
894 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), bytes);
898 static void __nf_conntrack_insert_prepare(struct nf_conn *ct)
900 struct nf_conn_tstamp *tstamp;
902 atomic_inc(&ct->ct_general.use);
903 ct->status |= IPS_CONFIRMED;
905 /* set conntrack timestamp, if enabled. */
906 tstamp = nf_conn_tstamp_find(ct);
908 tstamp->start = ktime_get_real_ns();
911 /* caller must hold locks to prevent concurrent changes */
912 static int __nf_ct_resolve_clash(struct sk_buff *skb,
913 struct nf_conntrack_tuple_hash *h)
915 /* This is the conntrack entry already in hashes that won race. */
916 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
917 enum ip_conntrack_info ctinfo;
918 struct nf_conn *loser_ct;
920 loser_ct = nf_ct_get(skb, &ctinfo);
922 if (nf_ct_is_dying(ct))
925 if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
926 nf_ct_match(ct, loser_ct)) {
927 struct net *net = nf_ct_net(ct);
929 nf_conntrack_get(&ct->ct_general);
931 nf_ct_acct_merge(ct, ctinfo, loser_ct);
932 nf_ct_add_to_dying_list(loser_ct);
933 nf_conntrack_put(&loser_ct->ct_general);
934 nf_ct_set(skb, ct, ctinfo);
936 NF_CT_STAT_INC(net, clash_resolve);
944 * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry
946 * @skb: skb that causes the collision
947 * @repl_idx: hash slot for reply direction
949 * Called when origin or reply direction had a clash.
950 * The skb can be handled without packet drop provided the reply direction
951 * is unique or there the existing entry has the identical tuple in both
954 * Caller must hold conntrack table locks to prevent concurrent updates.
956 * Returns NF_DROP if the clash could not be handled.
958 static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx)
960 struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb);
961 const struct nf_conntrack_zone *zone;
962 struct nf_conntrack_tuple_hash *h;
963 struct hlist_nulls_node *n;
966 zone = nf_ct_zone(loser_ct);
967 net = nf_ct_net(loser_ct);
969 /* Reply direction must never result in a clash, unless both origin
970 * and reply tuples are identical.
972 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) {
973 if (nf_ct_key_equal(h,
974 &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple,
976 return __nf_ct_resolve_clash(skb, h);
979 /* We want the clashing entry to go away real soon: 1 second timeout. */
980 loser_ct->timeout = nfct_time_stamp + HZ;
982 /* IPS_NAT_CLASH removes the entry automatically on the first
983 * reply. Also prevents UDP tracker from moving the entry to
984 * ASSURED state, i.e. the entry can always be evicted under
987 loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH;
989 __nf_conntrack_insert_prepare(loser_ct);
991 /* fake add for ORIGINAL dir: we want lookups to only find the entry
992 * already in the table. This also hides the clashing entry from
993 * ctnetlink iteration, i.e. conntrack -L won't show them.
995 hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
997 hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
998 &nf_conntrack_hash[repl_idx]);
1000 NF_CT_STAT_INC(net, clash_resolve);
1005 * nf_ct_resolve_clash - attempt to handle clash without packet drop
1007 * @skb: skb that causes the clash
1008 * @h: tuplehash of the clashing entry already in table
1009 * @reply_hash: hash slot for reply direction
1011 * A conntrack entry can be inserted to the connection tracking table
1012 * if there is no existing entry with an identical tuple.
1014 * If there is one, @skb (and the assocated, unconfirmed conntrack) has
1015 * to be dropped. In case @skb is retransmitted, next conntrack lookup
1016 * will find the already-existing entry.
1018 * The major problem with such packet drop is the extra delay added by
1019 * the packet loss -- it will take some time for a retransmit to occur
1020 * (or the sender to time out when waiting for a reply).
1022 * This function attempts to handle the situation without packet drop.
1024 * If @skb has no NAT transformation or if the colliding entries are
1025 * exactly the same, only the to-be-confirmed conntrack entry is discarded
1026 * and @skb is associated with the conntrack entry already in the table.
1028 * Failing that, the new, unconfirmed conntrack is still added to the table
1029 * provided that the collision only occurs in the ORIGINAL direction.
1030 * The new entry will be added only in the non-clashing REPLY direction,
1031 * so packets in the ORIGINAL direction will continue to match the existing
1032 * entry. The new entry will also have a fixed timeout so it expires --
1033 * due to the collision, it will only see reply traffic.
1035 * Returns NF_DROP if the clash could not be resolved.
1037 static __cold noinline int
1038 nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h,
1041 /* This is the conntrack entry already in hashes that won race. */
1042 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
1043 const struct nf_conntrack_l4proto *l4proto;
1044 enum ip_conntrack_info ctinfo;
1045 struct nf_conn *loser_ct;
1049 loser_ct = nf_ct_get(skb, &ctinfo);
1050 net = nf_ct_net(loser_ct);
1052 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1053 if (!l4proto->allow_clash)
1056 ret = __nf_ct_resolve_clash(skb, h);
1057 if (ret == NF_ACCEPT)
1060 ret = nf_ct_resolve_clash_harder(skb, reply_hash);
1061 if (ret == NF_ACCEPT)
1065 nf_ct_add_to_dying_list(loser_ct);
1066 NF_CT_STAT_INC(net, drop);
1067 NF_CT_STAT_INC(net, insert_failed);
1071 /* Confirm a connection given skb; places it in hash table */
1073 __nf_conntrack_confirm(struct sk_buff *skb)
1075 const struct nf_conntrack_zone *zone;
1076 unsigned int hash, reply_hash;
1077 struct nf_conntrack_tuple_hash *h;
1079 struct nf_conn_help *help;
1080 struct hlist_nulls_node *n;
1081 enum ip_conntrack_info ctinfo;
1083 unsigned int sequence;
1086 ct = nf_ct_get(skb, &ctinfo);
1087 net = nf_ct_net(ct);
1089 /* ipt_REJECT uses nf_conntrack_attach to attach related
1090 ICMP/TCP RST packets in other direction. Actual packet
1091 which created connection will be IP_CT_NEW or for an
1092 expected connection, IP_CT_RELATED. */
1093 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
1096 zone = nf_ct_zone(ct);
1100 sequence = read_seqcount_begin(&nf_conntrack_generation);
1101 /* reuse the hash saved before */
1102 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
1103 hash = scale_hash(hash);
1104 reply_hash = hash_conntrack(net,
1105 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
1107 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
1109 /* We're not in hash table, and we refuse to set up related
1110 * connections for unconfirmed conns. But packet copies and
1111 * REJECT will give spurious warnings here.
1114 /* Another skb with the same unconfirmed conntrack may
1115 * win the race. This may happen for bridge(br_flood)
1116 * or broadcast/multicast packets do skb_clone with
1117 * unconfirmed conntrack.
1119 if (unlikely(nf_ct_is_confirmed(ct))) {
1121 nf_conntrack_double_unlock(hash, reply_hash);
1126 pr_debug("Confirming conntrack %p\n", ct);
1127 /* We have to check the DYING flag after unlink to prevent
1128 * a race against nf_ct_get_next_corpse() possibly called from
1129 * user context, else we insert an already 'dead' hash, blocking
1130 * further use of that particular connection -JM.
1132 nf_ct_del_from_dying_or_unconfirmed_list(ct);
1134 if (unlikely(nf_ct_is_dying(ct))) {
1135 nf_ct_add_to_dying_list(ct);
1136 NF_CT_STAT_INC(net, insert_failed);
1140 /* See if there's one in the list already, including reverse:
1141 NAT could have grabbed it without realizing, since we're
1142 not in the hash. If there is, we lost race. */
1143 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
1144 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1148 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
1149 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1153 /* Timer relative to confirmation time, not original
1154 setting time, otherwise we'd get timer wrap in
1155 weird delay cases. */
1156 ct->timeout += nfct_time_stamp;
1158 __nf_conntrack_insert_prepare(ct);
1160 /* Since the lookup is lockless, hash insertion must be done after
1161 * starting the timer and setting the CONFIRMED bit. The RCU barriers
1162 * guarantee that no other CPU can find the conntrack before the above
1163 * stores are visible.
1165 __nf_conntrack_hash_insert(ct, hash, reply_hash);
1166 nf_conntrack_double_unlock(hash, reply_hash);
1169 help = nfct_help(ct);
1170 if (help && help->helper)
1171 nf_conntrack_event_cache(IPCT_HELPER, ct);
1173 nf_conntrack_event_cache(master_ct(ct) ?
1174 IPCT_RELATED : IPCT_NEW, ct);
1178 ret = nf_ct_resolve_clash(skb, h, reply_hash);
1180 nf_conntrack_double_unlock(hash, reply_hash);
1184 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
1186 /* Returns true if a connection correspondings to the tuple (required
1189 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
1190 const struct nf_conn *ignored_conntrack)
1192 struct net *net = nf_ct_net(ignored_conntrack);
1193 const struct nf_conntrack_zone *zone;
1194 struct nf_conntrack_tuple_hash *h;
1195 struct hlist_nulls_head *ct_hash;
1196 unsigned int hash, hsize;
1197 struct hlist_nulls_node *n;
1200 zone = nf_ct_zone(ignored_conntrack);
1204 nf_conntrack_get_ht(&ct_hash, &hsize);
1205 hash = __hash_conntrack(net, tuple, hsize);
1207 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
1208 ct = nf_ct_tuplehash_to_ctrack(h);
1210 if (ct == ignored_conntrack)
1213 if (nf_ct_is_expired(ct)) {
1214 nf_ct_gc_expired(ct);
1218 if (nf_ct_key_equal(h, tuple, zone, net)) {
1219 /* Tuple is taken already, so caller will need to find
1220 * a new source port to use.
1223 * If the *original tuples* are identical, then both
1224 * conntracks refer to the same flow.
1225 * This is a rare situation, it can occur e.g. when
1226 * more than one UDP packet is sent from same socket
1227 * in different threads.
1229 * Let nf_ct_resolve_clash() deal with this later.
1231 if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1232 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
1233 nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL))
1236 NF_CT_STAT_INC_ATOMIC(net, found);
1242 if (get_nulls_value(n) != hash) {
1243 NF_CT_STAT_INC_ATOMIC(net, search_restart);
1251 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
1253 #define NF_CT_EVICTION_RANGE 8
1255 /* There's a small race here where we may free a just-assured
1256 connection. Too bad: we're in trouble anyway. */
1257 static unsigned int early_drop_list(struct net *net,
1258 struct hlist_nulls_head *head)
1260 struct nf_conntrack_tuple_hash *h;
1261 struct hlist_nulls_node *n;
1262 unsigned int drops = 0;
1263 struct nf_conn *tmp;
1265 hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
1266 tmp = nf_ct_tuplehash_to_ctrack(h);
1268 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status))
1271 if (nf_ct_is_expired(tmp)) {
1272 nf_ct_gc_expired(tmp);
1276 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
1277 !net_eq(nf_ct_net(tmp), net) ||
1278 nf_ct_is_dying(tmp))
1281 if (!atomic_inc_not_zero(&tmp->ct_general.use))
1284 /* kill only if still in same netns -- might have moved due to
1285 * SLAB_TYPESAFE_BY_RCU rules.
1287 * We steal the timer reference. If that fails timer has
1288 * already fired or someone else deleted it. Just drop ref
1289 * and move to next entry.
1291 if (net_eq(nf_ct_net(tmp), net) &&
1292 nf_ct_is_confirmed(tmp) &&
1293 nf_ct_delete(tmp, 0, 0))
1302 static noinline int early_drop(struct net *net, unsigned int hash)
1304 unsigned int i, bucket;
1306 for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
1307 struct hlist_nulls_head *ct_hash;
1308 unsigned int hsize, drops;
1311 nf_conntrack_get_ht(&ct_hash, &hsize);
1313 bucket = reciprocal_scale(hash, hsize);
1315 bucket = (bucket + 1) % hsize;
1317 drops = early_drop_list(net, &ct_hash[bucket]);
1321 NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
1329 static bool gc_worker_skip_ct(const struct nf_conn *ct)
1331 return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct);
1334 static bool gc_worker_can_early_drop(const struct nf_conn *ct)
1336 const struct nf_conntrack_l4proto *l4proto;
1338 if (!test_bit(IPS_ASSURED_BIT, &ct->status))
1341 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1342 if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
1348 static void gc_worker(struct work_struct *work)
1350 unsigned int min_interval = max(HZ / GC_MAX_BUCKETS_DIV, 1u);
1351 unsigned int i, goal, buckets = 0, expired_count = 0;
1352 unsigned int nf_conntrack_max95 = 0;
1353 struct conntrack_gc_work *gc_work;
1354 unsigned int ratio, scanned = 0;
1355 unsigned long next_run;
1357 gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
1359 goal = nf_conntrack_htable_size / GC_MAX_BUCKETS_DIV;
1360 i = gc_work->last_bucket;
1361 if (gc_work->early_drop)
1362 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u;
1365 struct nf_conntrack_tuple_hash *h;
1366 struct hlist_nulls_head *ct_hash;
1367 struct hlist_nulls_node *n;
1368 unsigned int hashsz;
1369 struct nf_conn *tmp;
1374 nf_conntrack_get_ht(&ct_hash, &hashsz);
1378 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
1381 tmp = nf_ct_tuplehash_to_ctrack(h);
1384 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) {
1385 nf_ct_offload_timeout(tmp);
1389 if (nf_ct_is_expired(tmp)) {
1390 nf_ct_gc_expired(tmp);
1395 if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp))
1398 net = nf_ct_net(tmp);
1399 if (atomic_read(&net->ct.count) < nf_conntrack_max95)
1402 /* need to take reference to avoid possible races */
1403 if (!atomic_inc_not_zero(&tmp->ct_general.use))
1406 if (gc_worker_skip_ct(tmp)) {
1411 if (gc_worker_can_early_drop(tmp))
1417 /* could check get_nulls_value() here and restart if ct
1418 * was moved to another chain. But given gc is best-effort
1419 * we will just continue with next hash slot.
1423 } while (++buckets < goal);
1425 if (gc_work->exiting)
1429 * Eviction will normally happen from the packet path, and not
1430 * from this gc worker.
1432 * This worker is only here to reap expired entries when system went
1433 * idle after a busy period.
1435 * The heuristics below are supposed to balance conflicting goals:
1437 * 1. Minimize time until we notice a stale entry
1438 * 2. Maximize scan intervals to not waste cycles
1440 * Normally, expire ratio will be close to 0.
1442 * As soon as a sizeable fraction of the entries have expired
1443 * increase scan frequency.
1445 ratio = scanned ? expired_count * 100 / scanned : 0;
1446 if (ratio > GC_EVICT_RATIO) {
1447 gc_work->next_gc_run = min_interval;
1449 unsigned int max = GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV;
1451 BUILD_BUG_ON((GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV) == 0);
1453 gc_work->next_gc_run += min_interval;
1454 if (gc_work->next_gc_run > max)
1455 gc_work->next_gc_run = max;
1458 next_run = gc_work->next_gc_run;
1459 gc_work->last_bucket = i;
1460 gc_work->early_drop = false;
1461 queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run);
1464 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1466 INIT_DEFERRABLE_WORK(&gc_work->dwork, gc_worker);
1467 gc_work->next_gc_run = HZ;
1468 gc_work->exiting = false;
1471 static struct nf_conn *
1472 __nf_conntrack_alloc(struct net *net,
1473 const struct nf_conntrack_zone *zone,
1474 const struct nf_conntrack_tuple *orig,
1475 const struct nf_conntrack_tuple *repl,
1476 gfp_t gfp, u32 hash)
1480 /* We don't want any race condition at early drop stage */
1481 atomic_inc(&net->ct.count);
1483 if (nf_conntrack_max &&
1484 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
1485 if (!early_drop(net, hash)) {
1486 if (!conntrack_gc_work.early_drop)
1487 conntrack_gc_work.early_drop = true;
1488 atomic_dec(&net->ct.count);
1489 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1490 return ERR_PTR(-ENOMEM);
1495 * Do not use kmem_cache_zalloc(), as this cache uses
1496 * SLAB_TYPESAFE_BY_RCU.
1498 ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1502 spin_lock_init(&ct->lock);
1503 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1504 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1505 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1506 /* save hash for reusing when confirming */
1507 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1510 write_pnet(&ct->ct_net, net);
1511 memset(&ct->__nfct_init_offset, 0,
1512 offsetof(struct nf_conn, proto) -
1513 offsetof(struct nf_conn, __nfct_init_offset));
1515 nf_ct_zone_add(ct, zone);
1517 /* Because we use RCU lookups, we set ct_general.use to zero before
1518 * this is inserted in any list.
1520 atomic_set(&ct->ct_general.use, 0);
1523 atomic_dec(&net->ct.count);
1524 return ERR_PTR(-ENOMEM);
1527 struct nf_conn *nf_conntrack_alloc(struct net *net,
1528 const struct nf_conntrack_zone *zone,
1529 const struct nf_conntrack_tuple *orig,
1530 const struct nf_conntrack_tuple *repl,
1533 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1535 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1537 void nf_conntrack_free(struct nf_conn *ct)
1539 struct net *net = nf_ct_net(ct);
1541 /* A freed object has refcnt == 0, that's
1542 * the golden rule for SLAB_TYPESAFE_BY_RCU
1544 WARN_ON(atomic_read(&ct->ct_general.use) != 0);
1546 nf_ct_ext_destroy(ct);
1547 kmem_cache_free(nf_conntrack_cachep, ct);
1548 smp_mb__before_atomic();
1549 atomic_dec(&net->ct.count);
1551 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1554 /* Allocate a new conntrack: we return -ENOMEM if classification
1555 failed due to stress. Otherwise it really is unclassifiable. */
1556 static noinline struct nf_conntrack_tuple_hash *
1557 init_conntrack(struct net *net, struct nf_conn *tmpl,
1558 const struct nf_conntrack_tuple *tuple,
1559 struct sk_buff *skb,
1560 unsigned int dataoff, u32 hash)
1563 struct nf_conn_help *help;
1564 struct nf_conntrack_tuple repl_tuple;
1565 struct nf_conntrack_ecache *ecache;
1566 struct nf_conntrack_expect *exp = NULL;
1567 const struct nf_conntrack_zone *zone;
1568 struct nf_conn_timeout *timeout_ext;
1569 struct nf_conntrack_zone tmp;
1571 if (!nf_ct_invert_tuple(&repl_tuple, tuple)) {
1572 pr_debug("Can't invert tuple.\n");
1576 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1577 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1580 return (struct nf_conntrack_tuple_hash *)ct;
1582 if (!nf_ct_add_synproxy(ct, tmpl)) {
1583 nf_conntrack_free(ct);
1584 return ERR_PTR(-ENOMEM);
1587 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1590 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1593 nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1594 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1595 nf_ct_labels_ext_add(ct);
1597 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1598 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1599 ecache ? ecache->expmask : 0,
1603 if (net->ct.expect_count) {
1604 spin_lock(&nf_conntrack_expect_lock);
1605 exp = nf_ct_find_expectation(net, zone, tuple);
1607 pr_debug("expectation arrives ct=%p exp=%p\n",
1609 /* Welcome, Mr. Bond. We've been expecting you... */
1610 __set_bit(IPS_EXPECTED_BIT, &ct->status);
1611 /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1612 ct->master = exp->master;
1614 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
1616 rcu_assign_pointer(help->helper, exp->helper);
1619 #ifdef CONFIG_NF_CONNTRACK_MARK
1620 ct->mark = exp->master->mark;
1622 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1623 ct->secmark = exp->master->secmark;
1625 NF_CT_STAT_INC(net, expect_new);
1627 spin_unlock(&nf_conntrack_expect_lock);
1630 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
1632 /* Now it is inserted into the unconfirmed list, bump refcount */
1633 nf_conntrack_get(&ct->ct_general);
1634 nf_ct_add_to_unconfirmed_list(ct);
1640 exp->expectfn(ct, exp);
1641 nf_ct_expect_put(exp);
1644 return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1647 /* On success, returns 0, sets skb->_nfct | ctinfo */
1649 resolve_normal_ct(struct nf_conn *tmpl,
1650 struct sk_buff *skb,
1651 unsigned int dataoff,
1653 const struct nf_hook_state *state)
1655 const struct nf_conntrack_zone *zone;
1656 struct nf_conntrack_tuple tuple;
1657 struct nf_conntrack_tuple_hash *h;
1658 enum ip_conntrack_info ctinfo;
1659 struct nf_conntrack_zone tmp;
1663 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1664 dataoff, state->pf, protonum, state->net,
1666 pr_debug("Can't get tuple\n");
1670 /* look for tuple match */
1671 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1672 hash = hash_conntrack_raw(&tuple, state->net);
1673 h = __nf_conntrack_find_get(state->net, zone, &tuple, hash);
1675 h = init_conntrack(state->net, tmpl, &tuple,
1676 skb, dataoff, hash);
1682 ct = nf_ct_tuplehash_to_ctrack(h);
1684 /* It exists; we have (non-exclusive) reference. */
1685 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1686 ctinfo = IP_CT_ESTABLISHED_REPLY;
1688 /* Once we've had two way comms, always ESTABLISHED. */
1689 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1690 pr_debug("normal packet for %p\n", ct);
1691 ctinfo = IP_CT_ESTABLISHED;
1692 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1693 pr_debug("related packet for %p\n", ct);
1694 ctinfo = IP_CT_RELATED;
1696 pr_debug("new packet for %p\n", ct);
1700 nf_ct_set(skb, ct, ctinfo);
1705 * icmp packets need special treatment to handle error messages that are
1706 * related to a connection.
1708 * Callers need to check if skb has a conntrack assigned when this
1709 * helper returns; in such case skb belongs to an already known connection.
1711 static unsigned int __cold
1712 nf_conntrack_handle_icmp(struct nf_conn *tmpl,
1713 struct sk_buff *skb,
1714 unsigned int dataoff,
1716 const struct nf_hook_state *state)
1720 if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP)
1721 ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state);
1722 #if IS_ENABLED(CONFIG_IPV6)
1723 else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6)
1724 ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state);
1730 NF_CT_STAT_INC_ATOMIC(state->net, error);
1735 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb,
1736 enum ip_conntrack_info ctinfo)
1738 const unsigned int *timeout = nf_ct_timeout_lookup(ct);
1741 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout;
1743 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
1747 /* Returns verdict for packet, or -1 for invalid. */
1748 static int nf_conntrack_handle_packet(struct nf_conn *ct,
1749 struct sk_buff *skb,
1750 unsigned int dataoff,
1751 enum ip_conntrack_info ctinfo,
1752 const struct nf_hook_state *state)
1754 switch (nf_ct_protonum(ct)) {
1756 return nf_conntrack_tcp_packet(ct, skb, dataoff,
1759 return nf_conntrack_udp_packet(ct, skb, dataoff,
1762 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state);
1763 #if IS_ENABLED(CONFIG_IPV6)
1764 case IPPROTO_ICMPV6:
1765 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state);
1767 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
1768 case IPPROTO_UDPLITE:
1769 return nf_conntrack_udplite_packet(ct, skb, dataoff,
1772 #ifdef CONFIG_NF_CT_PROTO_SCTP
1774 return nf_conntrack_sctp_packet(ct, skb, dataoff,
1777 #ifdef CONFIG_NF_CT_PROTO_DCCP
1779 return nf_conntrack_dccp_packet(ct, skb, dataoff,
1782 #ifdef CONFIG_NF_CT_PROTO_GRE
1784 return nf_conntrack_gre_packet(ct, skb, dataoff,
1789 return generic_packet(ct, skb, ctinfo);
1793 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state)
1795 enum ip_conntrack_info ctinfo;
1796 struct nf_conn *ct, *tmpl;
1800 tmpl = nf_ct_get(skb, &ctinfo);
1801 if (tmpl || ctinfo == IP_CT_UNTRACKED) {
1802 /* Previously seen (loopback or untracked)? Ignore. */
1803 if ((tmpl && !nf_ct_is_template(tmpl)) ||
1804 ctinfo == IP_CT_UNTRACKED)
1809 /* rcu_read_lock()ed by nf_hook_thresh */
1810 dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum);
1812 pr_debug("not prepared to track yet or error occurred\n");
1813 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1818 if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) {
1819 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff,
1825 /* ICMP[v6] protocol trackers may assign one conntrack. */
1830 ret = resolve_normal_ct(tmpl, skb, dataoff,
1833 /* Too stressed to deal. */
1834 NF_CT_STAT_INC_ATOMIC(state->net, drop);
1839 ct = nf_ct_get(skb, &ctinfo);
1841 /* Not valid part of a connection */
1842 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1847 ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state);
1849 /* Invalid: inverse of the return code tells
1850 * the netfilter core what to do */
1851 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1852 nf_conntrack_put(&ct->ct_general);
1854 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1855 if (ret == -NF_DROP)
1856 NF_CT_STAT_INC_ATOMIC(state->net, drop);
1857 /* Special case: TCP tracker reports an attempt to reopen a
1858 * closed/aborted connection. We have to go back and create a
1861 if (ret == -NF_REPEAT)
1867 if (ctinfo == IP_CT_ESTABLISHED_REPLY &&
1868 !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1869 nf_conntrack_event_cache(IPCT_REPLY, ct);
1876 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1878 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
1879 implicitly racy: see __nf_conntrack_confirm */
1880 void nf_conntrack_alter_reply(struct nf_conn *ct,
1881 const struct nf_conntrack_tuple *newreply)
1883 struct nf_conn_help *help = nfct_help(ct);
1885 /* Should be unconfirmed, so not in hash table yet */
1886 WARN_ON(nf_ct_is_confirmed(ct));
1888 pr_debug("Altering reply tuple of %p to ", ct);
1889 nf_ct_dump_tuple(newreply);
1891 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1892 if (ct->master || (help && !hlist_empty(&help->expectations)))
1896 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1899 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1901 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1902 void __nf_ct_refresh_acct(struct nf_conn *ct,
1903 enum ip_conntrack_info ctinfo,
1904 const struct sk_buff *skb,
1908 /* Only update if this is not a fixed timeout */
1909 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1912 /* If not in hash table, timer will not be active yet */
1913 if (nf_ct_is_confirmed(ct))
1914 extra_jiffies += nfct_time_stamp;
1916 if (READ_ONCE(ct->timeout) != extra_jiffies)
1917 WRITE_ONCE(ct->timeout, extra_jiffies);
1920 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
1922 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1924 bool nf_ct_kill_acct(struct nf_conn *ct,
1925 enum ip_conntrack_info ctinfo,
1926 const struct sk_buff *skb)
1928 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
1930 return nf_ct_delete(ct, 0, 0);
1932 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
1934 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1936 #include <linux/netfilter/nfnetlink.h>
1937 #include <linux/netfilter/nfnetlink_conntrack.h>
1938 #include <linux/mutex.h>
1940 /* Generic function for tcp/udp/sctp/dccp and alike. */
1941 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1942 const struct nf_conntrack_tuple *tuple)
1944 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1945 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1946 goto nla_put_failure;
1952 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1954 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1955 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
1956 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
1958 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1960 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1961 struct nf_conntrack_tuple *t,
1964 if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) {
1965 if (!tb[CTA_PROTO_SRC_PORT])
1968 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1971 if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) {
1972 if (!tb[CTA_PROTO_DST_PORT])
1975 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1980 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1982 unsigned int nf_ct_port_nlattr_tuple_size(void)
1984 static unsigned int size __read_mostly;
1987 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1991 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1994 /* Used by ipt_REJECT and ip6t_REJECT. */
1995 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
1998 enum ip_conntrack_info ctinfo;
2000 /* This ICMP is in reverse direction to the packet which caused it */
2001 ct = nf_ct_get(skb, &ctinfo);
2002 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
2003 ctinfo = IP_CT_RELATED_REPLY;
2005 ctinfo = IP_CT_RELATED;
2007 /* Attach to new skbuff, and increment count */
2008 nf_ct_set(nskb, ct, ctinfo);
2009 nf_conntrack_get(skb_nfct(nskb));
2012 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb,
2014 enum ip_conntrack_info ctinfo)
2016 struct nf_conntrack_tuple_hash *h;
2017 struct nf_conntrack_tuple tuple;
2018 struct nf_nat_hook *nat_hook;
2019 unsigned int status;
2024 l3num = nf_ct_l3num(ct);
2026 dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
2030 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
2031 l4num, net, &tuple))
2034 if (ct->status & IPS_SRC_NAT) {
2035 memcpy(tuple.src.u3.all,
2036 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all,
2037 sizeof(tuple.src.u3.all));
2039 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all;
2042 if (ct->status & IPS_DST_NAT) {
2043 memcpy(tuple.dst.u3.all,
2044 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all,
2045 sizeof(tuple.dst.u3.all));
2047 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all;
2050 h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple);
2054 /* Store status bits of the conntrack that is clashing to re-do NAT
2055 * mangling according to what it has been done already to this packet.
2057 status = ct->status;
2060 ct = nf_ct_tuplehash_to_ctrack(h);
2061 nf_ct_set(skb, ct, ctinfo);
2063 nat_hook = rcu_dereference(nf_nat_hook);
2067 if (status & IPS_SRC_NAT &&
2068 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC,
2069 IP_CT_DIR_ORIGINAL) == NF_DROP)
2072 if (status & IPS_DST_NAT &&
2073 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST,
2074 IP_CT_DIR_ORIGINAL) == NF_DROP)
2080 /* This packet is coming from userspace via nf_queue, complete the packet
2081 * processing after the helper invocation in nf_confirm().
2083 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct,
2084 enum ip_conntrack_info ctinfo)
2086 const struct nf_conntrack_helper *helper;
2087 const struct nf_conn_help *help;
2090 help = nfct_help(ct);
2094 helper = rcu_dereference(help->helper);
2095 if (!(helper->flags & NF_CT_HELPER_F_USERSPACE))
2098 switch (nf_ct_l3num(ct)) {
2100 protoff = skb_network_offset(skb) + ip_hdrlen(skb);
2102 #if IS_ENABLED(CONFIG_IPV6)
2103 case NFPROTO_IPV6: {
2107 pnum = ipv6_hdr(skb)->nexthdr;
2108 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
2110 if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
2119 if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
2120 !nf_is_loopback_packet(skb)) {
2121 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
2122 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
2127 /* We've seen it coming out the other side: confirm it */
2128 return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0;
2131 static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
2133 enum ip_conntrack_info ctinfo;
2137 ct = nf_ct_get(skb, &ctinfo);
2141 if (!nf_ct_is_confirmed(ct)) {
2142 err = __nf_conntrack_update(net, skb, ct, ctinfo);
2146 ct = nf_ct_get(skb, &ctinfo);
2149 return nf_confirm_cthelper(skb, ct, ctinfo);
2152 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
2153 const struct sk_buff *skb)
2155 const struct nf_conntrack_tuple *src_tuple;
2156 const struct nf_conntrack_tuple_hash *hash;
2157 struct nf_conntrack_tuple srctuple;
2158 enum ip_conntrack_info ctinfo;
2161 ct = nf_ct_get(skb, &ctinfo);
2163 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo));
2164 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2168 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
2169 NFPROTO_IPV4, dev_net(skb->dev),
2173 hash = nf_conntrack_find_get(dev_net(skb->dev),
2179 ct = nf_ct_tuplehash_to_ctrack(hash);
2180 src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir);
2181 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2187 /* Bring out ya dead! */
2188 static struct nf_conn *
2189 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
2190 void *data, unsigned int *bucket)
2192 struct nf_conntrack_tuple_hash *h;
2194 struct hlist_nulls_node *n;
2197 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
2198 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
2200 nf_conntrack_lock(lockp);
2201 if (*bucket < nf_conntrack_htable_size) {
2202 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnnode) {
2203 if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY)
2205 /* All nf_conn objects are added to hash table twice, one
2206 * for original direction tuple, once for the reply tuple.
2208 * Exception: In the IPS_NAT_CLASH case, only the reply
2209 * tuple is added (the original tuple already existed for
2210 * a different object).
2212 * We only need to call the iterator once for each
2213 * conntrack, so we just use the 'reply' direction
2214 * tuple while iterating.
2216 ct = nf_ct_tuplehash_to_ctrack(h);
2228 atomic_inc(&ct->ct_general.use);
2234 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data),
2235 void *data, u32 portid, int report)
2237 unsigned int bucket = 0, sequence;
2243 sequence = read_seqcount_begin(&nf_conntrack_generation);
2245 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
2246 /* Time to push up daises... */
2248 nf_ct_delete(ct, portid, report);
2253 if (!read_seqcount_retry(&nf_conntrack_generation, sequence))
2260 int (*iter)(struct nf_conn *i, void *data);
2265 static int iter_net_only(struct nf_conn *i, void *data)
2267 struct iter_data *d = data;
2269 if (!net_eq(d->net, nf_ct_net(i)))
2272 return d->iter(i, d->data);
2276 __nf_ct_unconfirmed_destroy(struct net *net)
2280 for_each_possible_cpu(cpu) {
2281 struct nf_conntrack_tuple_hash *h;
2282 struct hlist_nulls_node *n;
2283 struct ct_pcpu *pcpu;
2285 pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2287 spin_lock_bh(&pcpu->lock);
2288 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
2291 ct = nf_ct_tuplehash_to_ctrack(h);
2293 /* we cannot call iter() on unconfirmed list, the
2294 * owning cpu can reallocate ct->ext at any time.
2296 set_bit(IPS_DYING_BIT, &ct->status);
2298 spin_unlock_bh(&pcpu->lock);
2303 void nf_ct_unconfirmed_destroy(struct net *net)
2307 if (atomic_read(&net->ct.count) > 0) {
2308 __nf_ct_unconfirmed_destroy(net);
2309 nf_queue_nf_hook_drop(net);
2313 EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy);
2315 void nf_ct_iterate_cleanup_net(struct net *net,
2316 int (*iter)(struct nf_conn *i, void *data),
2317 void *data, u32 portid, int report)
2323 if (atomic_read(&net->ct.count) == 0)
2330 nf_ct_iterate_cleanup(iter_net_only, &d, portid, report);
2332 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net);
2335 * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table
2336 * @iter: callback to invoke for each conntrack
2337 * @data: data to pass to @iter
2339 * Like nf_ct_iterate_cleanup, but first marks conntracks on the
2340 * unconfirmed list as dying (so they will not be inserted into
2343 * Can only be called in module exit path.
2346 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
2350 down_read(&net_rwsem);
2352 if (atomic_read(&net->ct.count) == 0)
2354 __nf_ct_unconfirmed_destroy(net);
2355 nf_queue_nf_hook_drop(net);
2357 up_read(&net_rwsem);
2359 /* Need to wait for netns cleanup worker to finish, if its
2360 * running -- it might have deleted a net namespace from
2361 * the global list, so our __nf_ct_unconfirmed_destroy() might
2362 * not have affected all namespaces.
2366 /* a conntrack could have been unlinked from unconfirmed list
2367 * before we grabbed pcpu lock in __nf_ct_unconfirmed_destroy().
2368 * This makes sure its inserted into conntrack table.
2372 nf_ct_iterate_cleanup(iter, data, 0, 0);
2374 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy);
2376 static int kill_all(struct nf_conn *i, void *data)
2378 return net_eq(nf_ct_net(i), data);
2381 void nf_conntrack_cleanup_start(void)
2383 conntrack_gc_work.exiting = true;
2384 RCU_INIT_POINTER(ip_ct_attach, NULL);
2387 void nf_conntrack_cleanup_end(void)
2389 RCU_INIT_POINTER(nf_ct_hook, NULL);
2390 cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2391 kvfree(nf_conntrack_hash);
2393 nf_conntrack_proto_fini();
2394 nf_conntrack_seqadj_fini();
2395 nf_conntrack_labels_fini();
2396 nf_conntrack_helper_fini();
2397 nf_conntrack_timeout_fini();
2398 nf_conntrack_ecache_fini();
2399 nf_conntrack_tstamp_fini();
2400 nf_conntrack_acct_fini();
2401 nf_conntrack_expect_fini();
2403 kmem_cache_destroy(nf_conntrack_cachep);
2407 * Mishearing the voices in his head, our hero wonders how he's
2408 * supposed to kill the mall.
2410 void nf_conntrack_cleanup_net(struct net *net)
2414 list_add(&net->exit_list, &single);
2415 nf_conntrack_cleanup_net_list(&single);
2418 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
2424 * This makes sure all current packets have passed through
2425 * netfilter framework. Roll on, two-stage module
2431 list_for_each_entry(net, net_exit_list, exit_list) {
2432 nf_ct_iterate_cleanup(kill_all, net, 0, 0);
2433 if (atomic_read(&net->ct.count) != 0)
2438 goto i_see_dead_people;
2441 list_for_each_entry(net, net_exit_list, exit_list) {
2442 nf_conntrack_proto_pernet_fini(net);
2443 nf_conntrack_ecache_pernet_fini(net);
2444 nf_conntrack_expect_pernet_fini(net);
2445 free_percpu(net->ct.stat);
2446 free_percpu(net->ct.pcpu_lists);
2450 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
2452 struct hlist_nulls_head *hash;
2453 unsigned int nr_slots, i;
2455 if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
2458 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
2459 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
2461 hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL);
2464 for (i = 0; i < nr_slots; i++)
2465 INIT_HLIST_NULLS_HEAD(&hash[i], i);
2469 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
2471 int nf_conntrack_hash_resize(unsigned int hashsize)
2474 unsigned int old_size;
2475 struct hlist_nulls_head *hash, *old_hash;
2476 struct nf_conntrack_tuple_hash *h;
2482 hash = nf_ct_alloc_hashtable(&hashsize, 1);
2486 old_size = nf_conntrack_htable_size;
2487 if (old_size == hashsize) {
2493 nf_conntrack_all_lock();
2494 write_seqcount_begin(&nf_conntrack_generation);
2496 /* Lookups in the old hash might happen in parallel, which means we
2497 * might get false negatives during connection lookup. New connections
2498 * created because of a false negative won't make it into the hash
2499 * though since that required taking the locks.
2502 for (i = 0; i < nf_conntrack_htable_size; i++) {
2503 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
2504 h = hlist_nulls_entry(nf_conntrack_hash[i].first,
2505 struct nf_conntrack_tuple_hash, hnnode);
2506 ct = nf_ct_tuplehash_to_ctrack(h);
2507 hlist_nulls_del_rcu(&h->hnnode);
2508 bucket = __hash_conntrack(nf_ct_net(ct),
2509 &h->tuple, hashsize);
2510 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
2513 old_size = nf_conntrack_htable_size;
2514 old_hash = nf_conntrack_hash;
2516 nf_conntrack_hash = hash;
2517 nf_conntrack_htable_size = hashsize;
2519 write_seqcount_end(&nf_conntrack_generation);
2520 nf_conntrack_all_unlock();
2528 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp)
2530 unsigned int hashsize;
2533 if (current->nsproxy->net_ns != &init_net)
2536 /* On boot, we can set this without any fancy locking. */
2537 if (!nf_conntrack_hash)
2538 return param_set_uint(val, kp);
2540 rc = kstrtouint(val, 0, &hashsize);
2544 return nf_conntrack_hash_resize(hashsize);
2547 static __always_inline unsigned int total_extension_size(void)
2549 /* remember to add new extensions below */
2550 BUILD_BUG_ON(NF_CT_EXT_NUM > 9);
2552 return sizeof(struct nf_ct_ext) +
2553 sizeof(struct nf_conn_help)
2554 #if IS_ENABLED(CONFIG_NF_NAT)
2555 + sizeof(struct nf_conn_nat)
2557 + sizeof(struct nf_conn_seqadj)
2558 + sizeof(struct nf_conn_acct)
2559 #ifdef CONFIG_NF_CONNTRACK_EVENTS
2560 + sizeof(struct nf_conntrack_ecache)
2562 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
2563 + sizeof(struct nf_conn_tstamp)
2565 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
2566 + sizeof(struct nf_conn_timeout)
2568 #ifdef CONFIG_NF_CONNTRACK_LABELS
2569 + sizeof(struct nf_conn_labels)
2571 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
2572 + sizeof(struct nf_conn_synproxy)
2577 int nf_conntrack_init_start(void)
2579 unsigned long nr_pages = totalram_pages();
2584 /* struct nf_ct_ext uses u8 to store offsets/size */
2585 BUILD_BUG_ON(total_extension_size() > 255u);
2587 seqcount_spinlock_init(&nf_conntrack_generation,
2588 &nf_conntrack_locks_all_lock);
2590 for (i = 0; i < CONNTRACK_LOCKS; i++)
2591 spin_lock_init(&nf_conntrack_locks[i]);
2593 if (!nf_conntrack_htable_size) {
2594 /* Idea from tcp.c: use 1/16384 of memory.
2595 * On i386: 32MB machine has 512 buckets.
2596 * >= 1GB machines have 16384 buckets.
2597 * >= 4GB machines have 65536 buckets.
2599 nf_conntrack_htable_size
2600 = (((nr_pages << PAGE_SHIFT) / 16384)
2601 / sizeof(struct hlist_head));
2602 if (nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
2603 nf_conntrack_htable_size = 65536;
2604 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
2605 nf_conntrack_htable_size = 16384;
2606 if (nf_conntrack_htable_size < 32)
2607 nf_conntrack_htable_size = 32;
2609 /* Use a max. factor of four by default to get the same max as
2610 * with the old struct list_heads. When a table size is given
2611 * we use the old value of 8 to avoid reducing the max.
2616 nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
2617 if (!nf_conntrack_hash)
2620 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
2622 nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
2623 sizeof(struct nf_conn),
2625 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
2626 if (!nf_conntrack_cachep)
2629 ret = nf_conntrack_expect_init();
2633 ret = nf_conntrack_acct_init();
2637 ret = nf_conntrack_tstamp_init();
2641 ret = nf_conntrack_ecache_init();
2645 ret = nf_conntrack_timeout_init();
2649 ret = nf_conntrack_helper_init();
2653 ret = nf_conntrack_labels_init();
2657 ret = nf_conntrack_seqadj_init();
2661 ret = nf_conntrack_proto_init();
2665 conntrack_gc_work_init(&conntrack_gc_work);
2666 queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ);
2671 nf_conntrack_seqadj_fini();
2673 nf_conntrack_labels_fini();
2675 nf_conntrack_helper_fini();
2677 nf_conntrack_timeout_fini();
2679 nf_conntrack_ecache_fini();
2681 nf_conntrack_tstamp_fini();
2683 nf_conntrack_acct_fini();
2685 nf_conntrack_expect_fini();
2687 kmem_cache_destroy(nf_conntrack_cachep);
2689 kvfree(nf_conntrack_hash);
2693 static struct nf_ct_hook nf_conntrack_hook = {
2694 .update = nf_conntrack_update,
2695 .destroy = destroy_conntrack,
2696 .get_tuple_skb = nf_conntrack_get_tuple_skb,
2699 void nf_conntrack_init_end(void)
2701 /* For use by REJECT target */
2702 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
2703 RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook);
2707 * We need to use special "null" values, not used in hash table
2709 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0)
2710 #define DYING_NULLS_VAL ((1<<30)+1)
2712 int nf_conntrack_init_net(struct net *net)
2717 BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER);
2718 BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS);
2719 atomic_set(&net->ct.count, 0);
2721 net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
2722 if (!net->ct.pcpu_lists)
2725 for_each_possible_cpu(cpu) {
2726 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2728 spin_lock_init(&pcpu->lock);
2729 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
2730 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
2733 net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
2735 goto err_pcpu_lists;
2737 ret = nf_conntrack_expect_pernet_init(net);
2741 nf_conntrack_acct_pernet_init(net);
2742 nf_conntrack_tstamp_pernet_init(net);
2743 nf_conntrack_ecache_pernet_init(net);
2744 nf_conntrack_helper_pernet_init(net);
2745 nf_conntrack_proto_pernet_init(net);
2750 free_percpu(net->ct.stat);
2752 free_percpu(net->ct.pcpu_lists);