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/siphash.h>
25 #include <linux/err.h>
26 #include <linux/percpu.h>
27 #include <linux/moduleparam.h>
28 #include <linux/notifier.h>
29 #include <linux/kernel.h>
30 #include <linux/netdevice.h>
31 #include <linux/socket.h>
33 #include <linux/nsproxy.h>
34 #include <linux/rculist_nulls.h>
36 #include <net/netfilter/nf_conntrack.h>
37 #include <net/netfilter/nf_conntrack_l4proto.h>
38 #include <net/netfilter/nf_conntrack_expect.h>
39 #include <net/netfilter/nf_conntrack_helper.h>
40 #include <net/netfilter/nf_conntrack_seqadj.h>
41 #include <net/netfilter/nf_conntrack_core.h>
42 #include <net/netfilter/nf_conntrack_extend.h>
43 #include <net/netfilter/nf_conntrack_acct.h>
44 #include <net/netfilter/nf_conntrack_ecache.h>
45 #include <net/netfilter/nf_conntrack_zones.h>
46 #include <net/netfilter/nf_conntrack_timestamp.h>
47 #include <net/netfilter/nf_conntrack_timeout.h>
48 #include <net/netfilter/nf_conntrack_labels.h>
49 #include <net/netfilter/nf_conntrack_synproxy.h>
50 #include <net/netfilter/nf_nat.h>
51 #include <net/netfilter/nf_nat_helper.h>
52 #include <net/netns/hash.h>
55 #include "nf_internals.h"
57 __cacheline_aligned_in_smp spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS];
58 EXPORT_SYMBOL_GPL(nf_conntrack_locks);
60 __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock);
61 EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock);
63 struct hlist_nulls_head *nf_conntrack_hash __read_mostly;
64 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
66 struct conntrack_gc_work {
67 struct delayed_work dwork;
76 static __read_mostly struct kmem_cache *nf_conntrack_cachep;
77 static DEFINE_SPINLOCK(nf_conntrack_locks_all_lock);
78 static __read_mostly bool nf_conntrack_locks_all;
80 /* serialize hash resizes and nf_ct_iterate_cleanup */
81 static DEFINE_MUTEX(nf_conntrack_mutex);
83 #define GC_SCAN_INTERVAL_MAX (60ul * HZ)
84 #define GC_SCAN_INTERVAL_MIN (1ul * HZ)
86 /* clamp timeouts to this value (TCP unacked) */
87 #define GC_SCAN_INTERVAL_CLAMP (300ul * HZ)
89 /* Initial bias pretending we have 100 entries at the upper bound so we don't
90 * wakeup often just because we have three entries with a 1s timeout while still
91 * allowing non-idle machines to wakeup more often when needed.
93 #define GC_SCAN_INITIAL_COUNT 100
94 #define GC_SCAN_INTERVAL_INIT GC_SCAN_INTERVAL_MAX
96 #define GC_SCAN_MAX_DURATION msecs_to_jiffies(10)
97 #define GC_SCAN_EXPIRED_MAX (64000u / HZ)
99 #define MIN_CHAINLEN 8u
100 #define MAX_CHAINLEN (32u - MIN_CHAINLEN)
102 static struct conntrack_gc_work conntrack_gc_work;
104 void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
106 /* 1) Acquire the lock */
109 /* 2) read nf_conntrack_locks_all, with ACQUIRE semantics
110 * It pairs with the smp_store_release() in nf_conntrack_all_unlock()
112 if (likely(smp_load_acquire(&nf_conntrack_locks_all) == false))
115 /* fast path failed, unlock */
118 /* Slow path 1) get global lock */
119 spin_lock(&nf_conntrack_locks_all_lock);
121 /* Slow path 2) get the lock we want */
124 /* Slow path 3) release the global lock */
125 spin_unlock(&nf_conntrack_locks_all_lock);
127 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
129 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2)
131 h1 %= CONNTRACK_LOCKS;
132 h2 %= CONNTRACK_LOCKS;
133 spin_unlock(&nf_conntrack_locks[h1]);
135 spin_unlock(&nf_conntrack_locks[h2]);
138 /* return true if we need to recompute hashes (in case hash table was resized) */
139 static bool nf_conntrack_double_lock(struct net *net, unsigned int h1,
140 unsigned int h2, unsigned int sequence)
142 h1 %= CONNTRACK_LOCKS;
143 h2 %= CONNTRACK_LOCKS;
145 nf_conntrack_lock(&nf_conntrack_locks[h1]);
147 spin_lock_nested(&nf_conntrack_locks[h2],
148 SINGLE_DEPTH_NESTING);
150 nf_conntrack_lock(&nf_conntrack_locks[h2]);
151 spin_lock_nested(&nf_conntrack_locks[h1],
152 SINGLE_DEPTH_NESTING);
154 if (read_seqcount_retry(&nf_conntrack_generation, sequence)) {
155 nf_conntrack_double_unlock(h1, h2);
161 static void nf_conntrack_all_lock(void)
162 __acquires(&nf_conntrack_locks_all_lock)
166 spin_lock(&nf_conntrack_locks_all_lock);
168 /* For nf_contrack_locks_all, only the latest time when another
169 * CPU will see an update is controlled, by the "release" of the
171 * The earliest time is not controlled, an thus KCSAN could detect
172 * a race when nf_conntract_lock() reads the variable.
173 * WRITE_ONCE() is used to ensure the compiler will not
174 * optimize the write.
176 WRITE_ONCE(nf_conntrack_locks_all, true);
178 for (i = 0; i < CONNTRACK_LOCKS; i++) {
179 spin_lock(&nf_conntrack_locks[i]);
181 /* This spin_unlock provides the "release" to ensure that
182 * nf_conntrack_locks_all==true is visible to everyone that
183 * acquired spin_lock(&nf_conntrack_locks[]).
185 spin_unlock(&nf_conntrack_locks[i]);
189 static void nf_conntrack_all_unlock(void)
190 __releases(&nf_conntrack_locks_all_lock)
192 /* All prior stores must be complete before we clear
193 * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
194 * might observe the false value but not the entire
196 * It pairs with the smp_load_acquire() in nf_conntrack_lock()
198 smp_store_release(&nf_conntrack_locks_all, false);
199 spin_unlock(&nf_conntrack_locks_all_lock);
202 unsigned int nf_conntrack_htable_size __read_mostly;
203 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
205 unsigned int nf_conntrack_max __read_mostly;
206 EXPORT_SYMBOL_GPL(nf_conntrack_max);
207 seqcount_spinlock_t nf_conntrack_generation __read_mostly;
208 static siphash_key_t nf_conntrack_hash_rnd __read_mostly;
210 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
212 const struct net *net)
215 struct nf_conntrack_man src;
216 union nf_inet_addr dst_addr;
221 } __aligned(SIPHASH_ALIGNMENT) combined;
223 get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
225 memset(&combined, 0, sizeof(combined));
227 /* The direction must be ignored, so handle usable members manually. */
228 combined.src = tuple->src;
229 combined.dst_addr = tuple->dst.u3;
230 combined.zone = zoneid;
231 combined.net_mix = net_hash_mix(net);
232 combined.dport = (__force __u16)tuple->dst.u.all;
233 combined.proto = tuple->dst.protonum;
235 return (u32)siphash(&combined, sizeof(combined), &nf_conntrack_hash_rnd);
238 static u32 scale_hash(u32 hash)
240 return reciprocal_scale(hash, nf_conntrack_htable_size);
243 static u32 __hash_conntrack(const struct net *net,
244 const struct nf_conntrack_tuple *tuple,
248 return reciprocal_scale(hash_conntrack_raw(tuple, zoneid, net), size);
251 static u32 hash_conntrack(const struct net *net,
252 const struct nf_conntrack_tuple *tuple,
255 return scale_hash(hash_conntrack_raw(tuple, zoneid, net));
258 static bool nf_ct_get_tuple_ports(const struct sk_buff *skb,
259 unsigned int dataoff,
260 struct nf_conntrack_tuple *tuple)
264 } _inet_hdr, *inet_hdr;
266 /* Actually only need first 4 bytes to get ports. */
267 inet_hdr = skb_header_pointer(skb, dataoff, sizeof(_inet_hdr), &_inet_hdr);
271 tuple->src.u.udp.port = inet_hdr->sport;
272 tuple->dst.u.udp.port = inet_hdr->dport;
277 nf_ct_get_tuple(const struct sk_buff *skb,
279 unsigned int dataoff,
283 struct nf_conntrack_tuple *tuple)
289 memset(tuple, 0, sizeof(*tuple));
291 tuple->src.l3num = l3num;
294 nhoff += offsetof(struct iphdr, saddr);
295 size = 2 * sizeof(__be32);
298 nhoff += offsetof(struct ipv6hdr, saddr);
299 size = sizeof(_addrs);
305 ap = skb_header_pointer(skb, nhoff, size, _addrs);
311 tuple->src.u3.ip = ap[0];
312 tuple->dst.u3.ip = ap[1];
315 memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
316 memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
320 tuple->dst.protonum = protonum;
321 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
324 #if IS_ENABLED(CONFIG_IPV6)
326 return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple);
329 return icmp_pkt_to_tuple(skb, dataoff, net, tuple);
330 #ifdef CONFIG_NF_CT_PROTO_GRE
332 return gre_pkt_to_tuple(skb, dataoff, net, tuple);
335 case IPPROTO_UDP: /* fallthrough */
336 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
337 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
338 case IPPROTO_UDPLITE:
339 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
341 #ifdef CONFIG_NF_CT_PROTO_SCTP
343 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
345 #ifdef CONFIG_NF_CT_PROTO_DCCP
347 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
356 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
360 const struct iphdr *iph;
363 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
367 /* Conntrack defragments packets, we might still see fragments
368 * inside ICMP packets though.
370 if (iph->frag_off & htons(IP_OFFSET))
373 dataoff = nhoff + (iph->ihl << 2);
374 *protonum = iph->protocol;
376 /* Check bogus IP headers */
377 if (dataoff > skb->len) {
378 pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
379 nhoff, iph->ihl << 2, skb->len);
385 #if IS_ENABLED(CONFIG_IPV6)
386 static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
390 unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
394 if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
395 &nexthdr, sizeof(nexthdr)) != 0) {
396 pr_debug("can't get nexthdr\n");
399 protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
401 * (protoff == skb->len) means the packet has not data, just
402 * IPv6 and possibly extensions headers, but it is tracked anyway
404 if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
405 pr_debug("can't find proto in pkt\n");
414 static int get_l4proto(const struct sk_buff *skb,
415 unsigned int nhoff, u8 pf, u8 *l4num)
419 return ipv4_get_l4proto(skb, nhoff, l4num);
420 #if IS_ENABLED(CONFIG_IPV6)
422 return ipv6_get_l4proto(skb, nhoff, l4num);
431 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
433 struct net *net, struct nf_conntrack_tuple *tuple)
438 protoff = get_l4proto(skb, nhoff, l3num, &protonum);
442 return nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple);
444 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
447 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
448 const struct nf_conntrack_tuple *orig)
450 memset(inverse, 0, sizeof(*inverse));
452 inverse->src.l3num = orig->src.l3num;
454 switch (orig->src.l3num) {
456 inverse->src.u3.ip = orig->dst.u3.ip;
457 inverse->dst.u3.ip = orig->src.u3.ip;
460 inverse->src.u3.in6 = orig->dst.u3.in6;
461 inverse->dst.u3.in6 = orig->src.u3.in6;
467 inverse->dst.dir = !orig->dst.dir;
469 inverse->dst.protonum = orig->dst.protonum;
471 switch (orig->dst.protonum) {
473 return nf_conntrack_invert_icmp_tuple(inverse, orig);
474 #if IS_ENABLED(CONFIG_IPV6)
476 return nf_conntrack_invert_icmpv6_tuple(inverse, orig);
480 inverse->src.u.all = orig->dst.u.all;
481 inverse->dst.u.all = orig->src.u.all;
484 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
486 /* Generate a almost-unique pseudo-id for a given conntrack.
488 * intentionally doesn't re-use any of the seeds used for hash
489 * table location, we assume id gets exposed to userspace.
491 * Following nf_conn items do not change throughout lifetime
495 * 2. nf_conn->master address (normally NULL)
496 * 3. the associated net namespace
497 * 4. the original direction tuple
499 u32 nf_ct_get_id(const struct nf_conn *ct)
501 static __read_mostly siphash_key_t ct_id_seed;
502 unsigned long a, b, c, d;
504 net_get_random_once(&ct_id_seed, sizeof(ct_id_seed));
506 a = (unsigned long)ct;
507 b = (unsigned long)ct->master;
508 c = (unsigned long)nf_ct_net(ct);
509 d = (unsigned long)siphash(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
510 sizeof(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple),
513 return siphash_4u64((u64)a, (u64)b, (u64)c, (u64)d, &ct_id_seed);
515 return siphash_4u32((u32)a, (u32)b, (u32)c, (u32)d, &ct_id_seed);
518 EXPORT_SYMBOL_GPL(nf_ct_get_id);
521 clean_from_lists(struct nf_conn *ct)
523 pr_debug("clean_from_lists(%p)\n", ct);
524 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
525 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
527 /* Destroy all pending expectations */
528 nf_ct_remove_expectations(ct);
531 /* must be called with local_bh_disable */
532 static void nf_ct_add_to_dying_list(struct nf_conn *ct)
534 struct ct_pcpu *pcpu;
536 /* add this conntrack to the (per cpu) dying list */
537 ct->cpu = smp_processor_id();
538 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
540 spin_lock(&pcpu->lock);
541 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
543 spin_unlock(&pcpu->lock);
546 /* must be called with local_bh_disable */
547 static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct)
549 struct ct_pcpu *pcpu;
551 /* add this conntrack to the (per cpu) unconfirmed list */
552 ct->cpu = smp_processor_id();
553 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
555 spin_lock(&pcpu->lock);
556 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
558 spin_unlock(&pcpu->lock);
561 /* must be called with local_bh_disable */
562 static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct)
564 struct ct_pcpu *pcpu;
566 /* We overload first tuple to link into unconfirmed or dying list.*/
567 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
569 spin_lock(&pcpu->lock);
570 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
571 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
572 spin_unlock(&pcpu->lock);
575 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
577 /* Released via nf_ct_destroy() */
578 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
579 const struct nf_conntrack_zone *zone,
582 struct nf_conn *tmpl, *p;
584 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) {
585 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags);
590 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
592 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
593 tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p;
596 tmpl = kzalloc(sizeof(*tmpl), flags);
601 tmpl->status = IPS_TEMPLATE;
602 write_pnet(&tmpl->ct_net, net);
603 nf_ct_zone_add(tmpl, zone);
604 refcount_set(&tmpl->ct_general.use, 1);
608 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
610 void nf_ct_tmpl_free(struct nf_conn *tmpl)
612 nf_ct_ext_destroy(tmpl);
614 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
615 kfree((char *)tmpl - tmpl->proto.tmpl_padto);
619 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free);
621 static void destroy_gre_conntrack(struct nf_conn *ct)
623 #ifdef CONFIG_NF_CT_PROTO_GRE
624 struct nf_conn *master = ct->master;
627 nf_ct_gre_keymap_destroy(master);
631 void nf_ct_destroy(struct nf_conntrack *nfct)
633 struct nf_conn *ct = (struct nf_conn *)nfct;
635 pr_debug("%s(%p)\n", __func__, ct);
636 WARN_ON(refcount_read(&nfct->use) != 0);
638 if (unlikely(nf_ct_is_template(ct))) {
643 if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE))
644 destroy_gre_conntrack(ct);
647 /* Expectations will have been removed in clean_from_lists,
648 * except TFTP can create an expectation on the first packet,
649 * before connection is in the list, so we need to clean here,
652 nf_ct_remove_expectations(ct);
654 nf_ct_del_from_dying_or_unconfirmed_list(ct);
659 nf_ct_put(ct->master);
661 pr_debug("%s: returning ct=%p to slab\n", __func__, ct);
662 nf_conntrack_free(ct);
664 EXPORT_SYMBOL(nf_ct_destroy);
666 static void nf_ct_delete_from_lists(struct nf_conn *ct)
668 struct net *net = nf_ct_net(ct);
669 unsigned int hash, reply_hash;
670 unsigned int sequence;
672 nf_ct_helper_destroy(ct);
676 sequence = read_seqcount_begin(&nf_conntrack_generation);
677 hash = hash_conntrack(net,
678 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
679 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL));
680 reply_hash = hash_conntrack(net,
681 &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
682 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY));
683 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
685 clean_from_lists(ct);
686 nf_conntrack_double_unlock(hash, reply_hash);
688 nf_ct_add_to_dying_list(ct);
693 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
695 struct nf_conn_tstamp *tstamp;
698 if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
701 tstamp = nf_conn_tstamp_find(ct);
703 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp;
705 tstamp->stop = ktime_get_real_ns();
707 tstamp->stop -= jiffies_to_nsecs(-timeout);
710 if (nf_conntrack_event_report(IPCT_DESTROY, ct,
711 portid, report) < 0) {
712 /* destroy event was not delivered. nf_ct_put will
713 * be done by event cache worker on redelivery.
715 nf_ct_delete_from_lists(ct);
716 nf_conntrack_ecache_work(nf_ct_net(ct), NFCT_ECACHE_DESTROY_FAIL);
721 if (nf_conntrack_ecache_dwork_pending(net))
722 nf_conntrack_ecache_work(net, NFCT_ECACHE_DESTROY_SENT);
723 nf_ct_delete_from_lists(ct);
727 EXPORT_SYMBOL_GPL(nf_ct_delete);
730 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
731 const struct nf_conntrack_tuple *tuple,
732 const struct nf_conntrack_zone *zone,
733 const struct net *net)
735 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
737 /* A conntrack can be recreated with the equal tuple,
738 * so we need to check that the conntrack is confirmed
740 return nf_ct_tuple_equal(tuple, &h->tuple) &&
741 nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
742 nf_ct_is_confirmed(ct) &&
743 net_eq(net, nf_ct_net(ct));
747 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2)
749 return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
750 &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
751 nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple,
752 &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) &&
753 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) &&
754 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) &&
755 net_eq(nf_ct_net(ct1), nf_ct_net(ct2));
758 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
759 static void nf_ct_gc_expired(struct nf_conn *ct)
761 if (!refcount_inc_not_zero(&ct->ct_general.use))
764 if (nf_ct_should_gc(ct))
772 * - Caller must take a reference on returned object
773 * and recheck nf_ct_tuple_equal(tuple, &h->tuple)
775 static struct nf_conntrack_tuple_hash *
776 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
777 const struct nf_conntrack_tuple *tuple, u32 hash)
779 struct nf_conntrack_tuple_hash *h;
780 struct hlist_nulls_head *ct_hash;
781 struct hlist_nulls_node *n;
782 unsigned int bucket, hsize;
785 nf_conntrack_get_ht(&ct_hash, &hsize);
786 bucket = reciprocal_scale(hash, hsize);
788 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
791 ct = nf_ct_tuplehash_to_ctrack(h);
792 if (nf_ct_is_expired(ct)) {
793 nf_ct_gc_expired(ct);
797 if (nf_ct_key_equal(h, tuple, zone, net))
801 * if the nulls value we got at the end of this lookup is
802 * not the expected one, we must restart lookup.
803 * We probably met an item that was moved to another chain.
805 if (get_nulls_value(n) != bucket) {
806 NF_CT_STAT_INC_ATOMIC(net, search_restart);
813 /* Find a connection corresponding to a tuple. */
814 static struct nf_conntrack_tuple_hash *
815 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
816 const struct nf_conntrack_tuple *tuple, u32 hash)
818 struct nf_conntrack_tuple_hash *h;
823 h = ____nf_conntrack_find(net, zone, tuple, hash);
825 /* We have a candidate that matches the tuple we're interested
826 * in, try to obtain a reference and re-check tuple
828 ct = nf_ct_tuplehash_to_ctrack(h);
829 if (likely(refcount_inc_not_zero(&ct->ct_general.use))) {
830 if (likely(nf_ct_key_equal(h, tuple, zone, net)))
833 /* TYPESAFE_BY_RCU recycled the candidate */
845 struct nf_conntrack_tuple_hash *
846 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
847 const struct nf_conntrack_tuple *tuple)
849 unsigned int rid, zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL);
850 struct nf_conntrack_tuple_hash *thash;
852 thash = __nf_conntrack_find_get(net, zone, tuple,
853 hash_conntrack_raw(tuple, zone_id, net));
858 rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY);
860 return __nf_conntrack_find_get(net, zone, tuple,
861 hash_conntrack_raw(tuple, rid, net));
864 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
866 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
868 unsigned int reply_hash)
870 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
871 &nf_conntrack_hash[hash]);
872 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
873 &nf_conntrack_hash[reply_hash]);
877 nf_conntrack_hash_check_insert(struct nf_conn *ct)
879 const struct nf_conntrack_zone *zone;
880 struct net *net = nf_ct_net(ct);
881 unsigned int hash, reply_hash;
882 struct nf_conntrack_tuple_hash *h;
883 struct hlist_nulls_node *n;
884 unsigned int max_chainlen;
885 unsigned int chainlen = 0;
886 unsigned int sequence;
889 zone = nf_ct_zone(ct);
893 sequence = read_seqcount_begin(&nf_conntrack_generation);
894 hash = hash_conntrack(net,
895 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
896 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL));
897 reply_hash = hash_conntrack(net,
898 &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
899 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY));
900 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
902 max_chainlen = MIN_CHAINLEN + prandom_u32_max(MAX_CHAINLEN);
904 /* See if there's one in the list already, including reverse */
905 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) {
906 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
910 if (chainlen++ > max_chainlen)
916 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) {
917 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
920 if (chainlen++ > max_chainlen)
925 /* The caller holds a reference to this object */
926 refcount_set(&ct->ct_general.use, 2);
927 __nf_conntrack_hash_insert(ct, hash, reply_hash);
928 nf_conntrack_double_unlock(hash, reply_hash);
929 NF_CT_STAT_INC(net, insert);
933 NF_CT_STAT_INC(net, chaintoolong);
936 nf_conntrack_double_unlock(hash, reply_hash);
940 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
942 void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets,
945 struct nf_conn_acct *acct;
947 acct = nf_conn_acct_find(ct);
949 struct nf_conn_counter *counter = acct->counter;
951 atomic64_add(packets, &counter[dir].packets);
952 atomic64_add(bytes, &counter[dir].bytes);
955 EXPORT_SYMBOL_GPL(nf_ct_acct_add);
957 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
958 const struct nf_conn *loser_ct)
960 struct nf_conn_acct *acct;
962 acct = nf_conn_acct_find(loser_ct);
964 struct nf_conn_counter *counter = acct->counter;
967 /* u32 should be fine since we must have seen one packet. */
968 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
969 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), bytes);
973 static void __nf_conntrack_insert_prepare(struct nf_conn *ct)
975 struct nf_conn_tstamp *tstamp;
977 refcount_inc(&ct->ct_general.use);
978 ct->status |= IPS_CONFIRMED;
980 /* set conntrack timestamp, if enabled. */
981 tstamp = nf_conn_tstamp_find(ct);
983 tstamp->start = ktime_get_real_ns();
986 /* caller must hold locks to prevent concurrent changes */
987 static int __nf_ct_resolve_clash(struct sk_buff *skb,
988 struct nf_conntrack_tuple_hash *h)
990 /* This is the conntrack entry already in hashes that won race. */
991 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
992 enum ip_conntrack_info ctinfo;
993 struct nf_conn *loser_ct;
995 loser_ct = nf_ct_get(skb, &ctinfo);
997 if (nf_ct_is_dying(ct))
1000 if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
1001 nf_ct_match(ct, loser_ct)) {
1002 struct net *net = nf_ct_net(ct);
1004 nf_conntrack_get(&ct->ct_general);
1006 nf_ct_acct_merge(ct, ctinfo, loser_ct);
1007 nf_ct_add_to_dying_list(loser_ct);
1008 nf_ct_put(loser_ct);
1009 nf_ct_set(skb, ct, ctinfo);
1011 NF_CT_STAT_INC(net, clash_resolve);
1019 * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry
1021 * @skb: skb that causes the collision
1022 * @repl_idx: hash slot for reply direction
1024 * Called when origin or reply direction had a clash.
1025 * The skb can be handled without packet drop provided the reply direction
1026 * is unique or there the existing entry has the identical tuple in both
1029 * Caller must hold conntrack table locks to prevent concurrent updates.
1031 * Returns NF_DROP if the clash could not be handled.
1033 static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx)
1035 struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb);
1036 const struct nf_conntrack_zone *zone;
1037 struct nf_conntrack_tuple_hash *h;
1038 struct hlist_nulls_node *n;
1041 zone = nf_ct_zone(loser_ct);
1042 net = nf_ct_net(loser_ct);
1044 /* Reply direction must never result in a clash, unless both origin
1045 * and reply tuples are identical.
1047 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) {
1048 if (nf_ct_key_equal(h,
1049 &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1051 return __nf_ct_resolve_clash(skb, h);
1054 /* We want the clashing entry to go away real soon: 1 second timeout. */
1055 WRITE_ONCE(loser_ct->timeout, nfct_time_stamp + HZ);
1057 /* IPS_NAT_CLASH removes the entry automatically on the first
1058 * reply. Also prevents UDP tracker from moving the entry to
1059 * ASSURED state, i.e. the entry can always be evicted under
1062 loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH;
1064 __nf_conntrack_insert_prepare(loser_ct);
1066 /* fake add for ORIGINAL dir: we want lookups to only find the entry
1067 * already in the table. This also hides the clashing entry from
1068 * ctnetlink iteration, i.e. conntrack -L won't show them.
1070 hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
1072 hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
1073 &nf_conntrack_hash[repl_idx]);
1075 NF_CT_STAT_INC(net, clash_resolve);
1080 * nf_ct_resolve_clash - attempt to handle clash without packet drop
1082 * @skb: skb that causes the clash
1083 * @h: tuplehash of the clashing entry already in table
1084 * @reply_hash: hash slot for reply direction
1086 * A conntrack entry can be inserted to the connection tracking table
1087 * if there is no existing entry with an identical tuple.
1089 * If there is one, @skb (and the assocated, unconfirmed conntrack) has
1090 * to be dropped. In case @skb is retransmitted, next conntrack lookup
1091 * will find the already-existing entry.
1093 * The major problem with such packet drop is the extra delay added by
1094 * the packet loss -- it will take some time for a retransmit to occur
1095 * (or the sender to time out when waiting for a reply).
1097 * This function attempts to handle the situation without packet drop.
1099 * If @skb has no NAT transformation or if the colliding entries are
1100 * exactly the same, only the to-be-confirmed conntrack entry is discarded
1101 * and @skb is associated with the conntrack entry already in the table.
1103 * Failing that, the new, unconfirmed conntrack is still added to the table
1104 * provided that the collision only occurs in the ORIGINAL direction.
1105 * The new entry will be added only in the non-clashing REPLY direction,
1106 * so packets in the ORIGINAL direction will continue to match the existing
1107 * entry. The new entry will also have a fixed timeout so it expires --
1108 * due to the collision, it will only see reply traffic.
1110 * Returns NF_DROP if the clash could not be resolved.
1112 static __cold noinline int
1113 nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h,
1116 /* This is the conntrack entry already in hashes that won race. */
1117 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
1118 const struct nf_conntrack_l4proto *l4proto;
1119 enum ip_conntrack_info ctinfo;
1120 struct nf_conn *loser_ct;
1124 loser_ct = nf_ct_get(skb, &ctinfo);
1125 net = nf_ct_net(loser_ct);
1127 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1128 if (!l4proto->allow_clash)
1131 ret = __nf_ct_resolve_clash(skb, h);
1132 if (ret == NF_ACCEPT)
1135 ret = nf_ct_resolve_clash_harder(skb, reply_hash);
1136 if (ret == NF_ACCEPT)
1140 nf_ct_add_to_dying_list(loser_ct);
1141 NF_CT_STAT_INC(net, drop);
1142 NF_CT_STAT_INC(net, insert_failed);
1146 /* Confirm a connection given skb; places it in hash table */
1148 __nf_conntrack_confirm(struct sk_buff *skb)
1150 unsigned int chainlen = 0, sequence, max_chainlen;
1151 const struct nf_conntrack_zone *zone;
1152 unsigned int hash, reply_hash;
1153 struct nf_conntrack_tuple_hash *h;
1155 struct nf_conn_help *help;
1156 struct hlist_nulls_node *n;
1157 enum ip_conntrack_info ctinfo;
1161 ct = nf_ct_get(skb, &ctinfo);
1162 net = nf_ct_net(ct);
1164 /* ipt_REJECT uses nf_conntrack_attach to attach related
1165 ICMP/TCP RST packets in other direction. Actual packet
1166 which created connection will be IP_CT_NEW or for an
1167 expected connection, IP_CT_RELATED. */
1168 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
1171 zone = nf_ct_zone(ct);
1175 sequence = read_seqcount_begin(&nf_conntrack_generation);
1176 /* reuse the hash saved before */
1177 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
1178 hash = scale_hash(hash);
1179 reply_hash = hash_conntrack(net,
1180 &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1181 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY));
1182 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
1184 /* We're not in hash table, and we refuse to set up related
1185 * connections for unconfirmed conns. But packet copies and
1186 * REJECT will give spurious warnings here.
1189 /* Another skb with the same unconfirmed conntrack may
1190 * win the race. This may happen for bridge(br_flood)
1191 * or broadcast/multicast packets do skb_clone with
1192 * unconfirmed conntrack.
1194 if (unlikely(nf_ct_is_confirmed(ct))) {
1196 nf_conntrack_double_unlock(hash, reply_hash);
1201 pr_debug("Confirming conntrack %p\n", ct);
1202 /* We have to check the DYING flag after unlink to prevent
1203 * a race against nf_ct_get_next_corpse() possibly called from
1204 * user context, else we insert an already 'dead' hash, blocking
1205 * further use of that particular connection -JM.
1207 nf_ct_del_from_dying_or_unconfirmed_list(ct);
1209 if (unlikely(nf_ct_is_dying(ct))) {
1210 nf_ct_add_to_dying_list(ct);
1211 NF_CT_STAT_INC(net, insert_failed);
1215 max_chainlen = MIN_CHAINLEN + prandom_u32_max(MAX_CHAINLEN);
1216 /* See if there's one in the list already, including reverse:
1217 NAT could have grabbed it without realizing, since we're
1218 not in the hash. If there is, we lost race. */
1219 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) {
1220 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1223 if (chainlen++ > max_chainlen)
1228 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) {
1229 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1232 if (chainlen++ > max_chainlen) {
1234 nf_ct_add_to_dying_list(ct);
1235 NF_CT_STAT_INC(net, chaintoolong);
1236 NF_CT_STAT_INC(net, insert_failed);
1242 /* Timer relative to confirmation time, not original
1243 setting time, otherwise we'd get timer wrap in
1244 weird delay cases. */
1245 ct->timeout += nfct_time_stamp;
1247 __nf_conntrack_insert_prepare(ct);
1249 /* Since the lookup is lockless, hash insertion must be done after
1250 * starting the timer and setting the CONFIRMED bit. The RCU barriers
1251 * guarantee that no other CPU can find the conntrack before the above
1252 * stores are visible.
1254 __nf_conntrack_hash_insert(ct, hash, reply_hash);
1255 nf_conntrack_double_unlock(hash, reply_hash);
1258 help = nfct_help(ct);
1259 if (help && help->helper)
1260 nf_conntrack_event_cache(IPCT_HELPER, ct);
1262 nf_conntrack_event_cache(master_ct(ct) ?
1263 IPCT_RELATED : IPCT_NEW, ct);
1267 ret = nf_ct_resolve_clash(skb, h, reply_hash);
1269 nf_conntrack_double_unlock(hash, reply_hash);
1273 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
1275 /* Returns true if a connection correspondings to the tuple (required
1278 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
1279 const struct nf_conn *ignored_conntrack)
1281 struct net *net = nf_ct_net(ignored_conntrack);
1282 const struct nf_conntrack_zone *zone;
1283 struct nf_conntrack_tuple_hash *h;
1284 struct hlist_nulls_head *ct_hash;
1285 unsigned int hash, hsize;
1286 struct hlist_nulls_node *n;
1289 zone = nf_ct_zone(ignored_conntrack);
1293 nf_conntrack_get_ht(&ct_hash, &hsize);
1294 hash = __hash_conntrack(net, tuple, nf_ct_zone_id(zone, IP_CT_DIR_REPLY), hsize);
1296 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
1297 ct = nf_ct_tuplehash_to_ctrack(h);
1299 if (ct == ignored_conntrack)
1302 if (nf_ct_is_expired(ct)) {
1303 nf_ct_gc_expired(ct);
1307 if (nf_ct_key_equal(h, tuple, zone, net)) {
1308 /* Tuple is taken already, so caller will need to find
1309 * a new source port to use.
1312 * If the *original tuples* are identical, then both
1313 * conntracks refer to the same flow.
1314 * This is a rare situation, it can occur e.g. when
1315 * more than one UDP packet is sent from same socket
1316 * in different threads.
1318 * Let nf_ct_resolve_clash() deal with this later.
1320 if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1321 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
1322 nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL))
1325 NF_CT_STAT_INC_ATOMIC(net, found);
1331 if (get_nulls_value(n) != hash) {
1332 NF_CT_STAT_INC_ATOMIC(net, search_restart);
1340 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
1342 #define NF_CT_EVICTION_RANGE 8
1344 /* There's a small race here where we may free a just-assured
1345 connection. Too bad: we're in trouble anyway. */
1346 static unsigned int early_drop_list(struct net *net,
1347 struct hlist_nulls_head *head)
1349 struct nf_conntrack_tuple_hash *h;
1350 struct hlist_nulls_node *n;
1351 unsigned int drops = 0;
1352 struct nf_conn *tmp;
1354 hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
1355 tmp = nf_ct_tuplehash_to_ctrack(h);
1357 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status))
1360 if (nf_ct_is_expired(tmp)) {
1361 nf_ct_gc_expired(tmp);
1365 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
1366 !net_eq(nf_ct_net(tmp), net) ||
1367 nf_ct_is_dying(tmp))
1370 if (!refcount_inc_not_zero(&tmp->ct_general.use))
1373 /* kill only if still in same netns -- might have moved due to
1374 * SLAB_TYPESAFE_BY_RCU rules.
1376 * We steal the timer reference. If that fails timer has
1377 * already fired or someone else deleted it. Just drop ref
1378 * and move to next entry.
1380 if (net_eq(nf_ct_net(tmp), net) &&
1381 nf_ct_is_confirmed(tmp) &&
1382 nf_ct_delete(tmp, 0, 0))
1391 static noinline int early_drop(struct net *net, unsigned int hash)
1393 unsigned int i, bucket;
1395 for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
1396 struct hlist_nulls_head *ct_hash;
1397 unsigned int hsize, drops;
1400 nf_conntrack_get_ht(&ct_hash, &hsize);
1402 bucket = reciprocal_scale(hash, hsize);
1404 bucket = (bucket + 1) % hsize;
1406 drops = early_drop_list(net, &ct_hash[bucket]);
1410 NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
1418 static bool gc_worker_skip_ct(const struct nf_conn *ct)
1420 return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct);
1423 static bool gc_worker_can_early_drop(const struct nf_conn *ct)
1425 const struct nf_conntrack_l4proto *l4proto;
1427 if (!test_bit(IPS_ASSURED_BIT, &ct->status))
1430 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1431 if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
1437 static void gc_worker(struct work_struct *work)
1439 unsigned int i, hashsz, nf_conntrack_max95 = 0;
1440 u32 end_time, start_time = nfct_time_stamp;
1441 struct conntrack_gc_work *gc_work;
1442 unsigned int expired_count = 0;
1443 unsigned long next_run;
1447 gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
1449 i = gc_work->next_bucket;
1450 if (gc_work->early_drop)
1451 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u;
1454 gc_work->avg_timeout = GC_SCAN_INTERVAL_INIT;
1455 gc_work->count = GC_SCAN_INITIAL_COUNT;
1456 gc_work->start_time = start_time;
1459 next_run = gc_work->avg_timeout;
1460 count = gc_work->count;
1462 end_time = start_time + GC_SCAN_MAX_DURATION;
1465 struct nf_conntrack_tuple_hash *h;
1466 struct hlist_nulls_head *ct_hash;
1467 struct hlist_nulls_node *n;
1468 struct nf_conn *tmp;
1472 nf_conntrack_get_ht(&ct_hash, &hashsz);
1478 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
1479 struct nf_conntrack_net *cnet;
1483 tmp = nf_ct_tuplehash_to_ctrack(h);
1485 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) {
1486 nf_ct_offload_timeout(tmp);
1490 if (expired_count > GC_SCAN_EXPIRED_MAX) {
1493 gc_work->next_bucket = i;
1494 gc_work->avg_timeout = next_run;
1495 gc_work->count = count;
1497 delta_time = nfct_time_stamp - gc_work->start_time;
1499 /* re-sched immediately if total cycle time is exceeded */
1500 next_run = delta_time < (s32)GC_SCAN_INTERVAL_MAX;
1504 if (nf_ct_is_expired(tmp)) {
1505 nf_ct_gc_expired(tmp);
1510 expires = clamp(nf_ct_expires(tmp), GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_CLAMP);
1511 expires = (expires - (long)next_run) / ++count;
1512 next_run += expires;
1514 if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp))
1517 net = nf_ct_net(tmp);
1518 cnet = nf_ct_pernet(net);
1519 if (atomic_read(&cnet->count) < nf_conntrack_max95)
1522 /* need to take reference to avoid possible races */
1523 if (!refcount_inc_not_zero(&tmp->ct_general.use))
1526 if (gc_worker_skip_ct(tmp)) {
1531 if (gc_worker_can_early_drop(tmp)) {
1539 /* could check get_nulls_value() here and restart if ct
1540 * was moved to another chain. But given gc is best-effort
1541 * we will just continue with next hash slot.
1547 delta_time = nfct_time_stamp - end_time;
1548 if (delta_time > 0 && i < hashsz) {
1549 gc_work->avg_timeout = next_run;
1550 gc_work->count = count;
1551 gc_work->next_bucket = i;
1555 } while (i < hashsz);
1557 gc_work->next_bucket = 0;
1559 next_run = clamp(next_run, GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_MAX);
1561 delta_time = max_t(s32, nfct_time_stamp - gc_work->start_time, 1);
1562 if (next_run > (unsigned long)delta_time)
1563 next_run -= delta_time;
1568 if (gc_work->exiting)
1572 gc_work->early_drop = false;
1574 queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run);
1577 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1579 INIT_DELAYED_WORK(&gc_work->dwork, gc_worker);
1580 gc_work->exiting = false;
1583 static struct nf_conn *
1584 __nf_conntrack_alloc(struct net *net,
1585 const struct nf_conntrack_zone *zone,
1586 const struct nf_conntrack_tuple *orig,
1587 const struct nf_conntrack_tuple *repl,
1588 gfp_t gfp, u32 hash)
1590 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
1591 unsigned int ct_count;
1594 /* We don't want any race condition at early drop stage */
1595 ct_count = atomic_inc_return(&cnet->count);
1597 if (nf_conntrack_max && unlikely(ct_count > nf_conntrack_max)) {
1598 if (!early_drop(net, hash)) {
1599 if (!conntrack_gc_work.early_drop)
1600 conntrack_gc_work.early_drop = true;
1601 atomic_dec(&cnet->count);
1602 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1603 return ERR_PTR(-ENOMEM);
1608 * Do not use kmem_cache_zalloc(), as this cache uses
1609 * SLAB_TYPESAFE_BY_RCU.
1611 ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1615 spin_lock_init(&ct->lock);
1616 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1617 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1618 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1619 /* save hash for reusing when confirming */
1620 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1622 WRITE_ONCE(ct->timeout, 0);
1623 write_pnet(&ct->ct_net, net);
1624 memset(&ct->__nfct_init_offset, 0,
1625 offsetof(struct nf_conn, proto) -
1626 offsetof(struct nf_conn, __nfct_init_offset));
1628 nf_ct_zone_add(ct, zone);
1630 /* Because we use RCU lookups, we set ct_general.use to zero before
1631 * this is inserted in any list.
1633 refcount_set(&ct->ct_general.use, 0);
1636 atomic_dec(&cnet->count);
1637 return ERR_PTR(-ENOMEM);
1640 struct nf_conn *nf_conntrack_alloc(struct net *net,
1641 const struct nf_conntrack_zone *zone,
1642 const struct nf_conntrack_tuple *orig,
1643 const struct nf_conntrack_tuple *repl,
1646 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1648 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1650 void nf_conntrack_free(struct nf_conn *ct)
1652 struct net *net = nf_ct_net(ct);
1653 struct nf_conntrack_net *cnet;
1655 /* A freed object has refcnt == 0, that's
1656 * the golden rule for SLAB_TYPESAFE_BY_RCU
1658 WARN_ON(refcount_read(&ct->ct_general.use) != 0);
1660 nf_ct_ext_destroy(ct);
1661 kmem_cache_free(nf_conntrack_cachep, ct);
1662 cnet = nf_ct_pernet(net);
1664 smp_mb__before_atomic();
1665 atomic_dec(&cnet->count);
1667 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1670 /* Allocate a new conntrack: we return -ENOMEM if classification
1671 failed due to stress. Otherwise it really is unclassifiable. */
1672 static noinline struct nf_conntrack_tuple_hash *
1673 init_conntrack(struct net *net, struct nf_conn *tmpl,
1674 const struct nf_conntrack_tuple *tuple,
1675 struct sk_buff *skb,
1676 unsigned int dataoff, u32 hash)
1679 struct nf_conn_help *help;
1680 struct nf_conntrack_tuple repl_tuple;
1681 struct nf_conntrack_ecache *ecache;
1682 struct nf_conntrack_expect *exp = NULL;
1683 const struct nf_conntrack_zone *zone;
1684 struct nf_conn_timeout *timeout_ext;
1685 struct nf_conntrack_zone tmp;
1686 struct nf_conntrack_net *cnet;
1688 if (!nf_ct_invert_tuple(&repl_tuple, tuple)) {
1689 pr_debug("Can't invert tuple.\n");
1693 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1694 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1697 return (struct nf_conntrack_tuple_hash *)ct;
1699 if (!nf_ct_add_synproxy(ct, tmpl)) {
1700 nf_conntrack_free(ct);
1701 return ERR_PTR(-ENOMEM);
1704 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1707 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1710 nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1711 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1712 nf_ct_labels_ext_add(ct);
1714 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1715 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1716 ecache ? ecache->expmask : 0,
1720 cnet = nf_ct_pernet(net);
1721 if (cnet->expect_count) {
1722 spin_lock(&nf_conntrack_expect_lock);
1723 exp = nf_ct_find_expectation(net, zone, tuple);
1725 pr_debug("expectation arrives ct=%p exp=%p\n",
1727 /* Welcome, Mr. Bond. We've been expecting you... */
1728 __set_bit(IPS_EXPECTED_BIT, &ct->status);
1729 /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1730 ct->master = exp->master;
1732 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
1734 rcu_assign_pointer(help->helper, exp->helper);
1737 #ifdef CONFIG_NF_CONNTRACK_MARK
1738 ct->mark = READ_ONCE(exp->master->mark);
1740 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1741 ct->secmark = exp->master->secmark;
1743 NF_CT_STAT_INC(net, expect_new);
1745 spin_unlock(&nf_conntrack_expect_lock);
1748 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
1750 /* Now it is inserted into the unconfirmed list, set refcount to 1. */
1751 refcount_set(&ct->ct_general.use, 1);
1752 nf_ct_add_to_unconfirmed_list(ct);
1758 exp->expectfn(ct, exp);
1759 nf_ct_expect_put(exp);
1762 return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1765 /* On success, returns 0, sets skb->_nfct | ctinfo */
1767 resolve_normal_ct(struct nf_conn *tmpl,
1768 struct sk_buff *skb,
1769 unsigned int dataoff,
1771 const struct nf_hook_state *state)
1773 const struct nf_conntrack_zone *zone;
1774 struct nf_conntrack_tuple tuple;
1775 struct nf_conntrack_tuple_hash *h;
1776 enum ip_conntrack_info ctinfo;
1777 struct nf_conntrack_zone tmp;
1778 u32 hash, zone_id, rid;
1781 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1782 dataoff, state->pf, protonum, state->net,
1784 pr_debug("Can't get tuple\n");
1788 /* look for tuple match */
1789 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1791 zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL);
1792 hash = hash_conntrack_raw(&tuple, zone_id, state->net);
1793 h = __nf_conntrack_find_get(state->net, zone, &tuple, hash);
1796 rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY);
1797 if (zone_id != rid) {
1798 u32 tmp = hash_conntrack_raw(&tuple, rid, state->net);
1800 h = __nf_conntrack_find_get(state->net, zone, &tuple, tmp);
1805 h = init_conntrack(state->net, tmpl, &tuple,
1806 skb, dataoff, hash);
1812 ct = nf_ct_tuplehash_to_ctrack(h);
1814 /* It exists; we have (non-exclusive) reference. */
1815 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1816 ctinfo = IP_CT_ESTABLISHED_REPLY;
1818 /* Once we've had two way comms, always ESTABLISHED. */
1819 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1820 pr_debug("normal packet for %p\n", ct);
1821 ctinfo = IP_CT_ESTABLISHED;
1822 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1823 pr_debug("related packet for %p\n", ct);
1824 ctinfo = IP_CT_RELATED;
1826 pr_debug("new packet for %p\n", ct);
1830 nf_ct_set(skb, ct, ctinfo);
1835 * icmp packets need special treatment to handle error messages that are
1836 * related to a connection.
1838 * Callers need to check if skb has a conntrack assigned when this
1839 * helper returns; in such case skb belongs to an already known connection.
1841 static unsigned int __cold
1842 nf_conntrack_handle_icmp(struct nf_conn *tmpl,
1843 struct sk_buff *skb,
1844 unsigned int dataoff,
1846 const struct nf_hook_state *state)
1850 if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP)
1851 ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state);
1852 #if IS_ENABLED(CONFIG_IPV6)
1853 else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6)
1854 ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state);
1860 NF_CT_STAT_INC_ATOMIC(state->net, error);
1865 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb,
1866 enum ip_conntrack_info ctinfo)
1868 const unsigned int *timeout = nf_ct_timeout_lookup(ct);
1871 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout;
1873 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
1877 /* Returns verdict for packet, or -1 for invalid. */
1878 static int nf_conntrack_handle_packet(struct nf_conn *ct,
1879 struct sk_buff *skb,
1880 unsigned int dataoff,
1881 enum ip_conntrack_info ctinfo,
1882 const struct nf_hook_state *state)
1884 switch (nf_ct_protonum(ct)) {
1886 return nf_conntrack_tcp_packet(ct, skb, dataoff,
1889 return nf_conntrack_udp_packet(ct, skb, dataoff,
1892 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state);
1893 #if IS_ENABLED(CONFIG_IPV6)
1894 case IPPROTO_ICMPV6:
1895 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state);
1897 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
1898 case IPPROTO_UDPLITE:
1899 return nf_conntrack_udplite_packet(ct, skb, dataoff,
1902 #ifdef CONFIG_NF_CT_PROTO_SCTP
1904 return nf_conntrack_sctp_packet(ct, skb, dataoff,
1907 #ifdef CONFIG_NF_CT_PROTO_DCCP
1909 return nf_conntrack_dccp_packet(ct, skb, dataoff,
1912 #ifdef CONFIG_NF_CT_PROTO_GRE
1914 return nf_conntrack_gre_packet(ct, skb, dataoff,
1919 return generic_packet(ct, skb, ctinfo);
1923 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state)
1925 enum ip_conntrack_info ctinfo;
1926 struct nf_conn *ct, *tmpl;
1930 tmpl = nf_ct_get(skb, &ctinfo);
1931 if (tmpl || ctinfo == IP_CT_UNTRACKED) {
1932 /* Previously seen (loopback or untracked)? Ignore. */
1933 if ((tmpl && !nf_ct_is_template(tmpl)) ||
1934 ctinfo == IP_CT_UNTRACKED)
1939 /* rcu_read_lock()ed by nf_hook_thresh */
1940 dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum);
1942 pr_debug("not prepared to track yet or error occurred\n");
1943 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1948 if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) {
1949 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff,
1955 /* ICMP[v6] protocol trackers may assign one conntrack. */
1960 ret = resolve_normal_ct(tmpl, skb, dataoff,
1963 /* Too stressed to deal. */
1964 NF_CT_STAT_INC_ATOMIC(state->net, drop);
1969 ct = nf_ct_get(skb, &ctinfo);
1971 /* Not valid part of a connection */
1972 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1977 ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state);
1979 /* Invalid: inverse of the return code tells
1980 * the netfilter core what to do */
1981 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1984 /* Special case: TCP tracker reports an attempt to reopen a
1985 * closed/aborted connection. We have to go back and create a
1988 if (ret == -NF_REPEAT)
1991 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1992 if (ret == -NF_DROP)
1993 NF_CT_STAT_INC_ATOMIC(state->net, drop);
1999 if (ctinfo == IP_CT_ESTABLISHED_REPLY &&
2000 !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
2001 nf_conntrack_event_cache(IPCT_REPLY, ct);
2008 EXPORT_SYMBOL_GPL(nf_conntrack_in);
2010 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
2011 implicitly racy: see __nf_conntrack_confirm */
2012 void nf_conntrack_alter_reply(struct nf_conn *ct,
2013 const struct nf_conntrack_tuple *newreply)
2015 struct nf_conn_help *help = nfct_help(ct);
2017 /* Should be unconfirmed, so not in hash table yet */
2018 WARN_ON(nf_ct_is_confirmed(ct));
2020 pr_debug("Altering reply tuple of %p to ", ct);
2021 nf_ct_dump_tuple(newreply);
2023 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
2024 if (ct->master || (help && !hlist_empty(&help->expectations)))
2028 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
2031 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
2033 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
2034 void __nf_ct_refresh_acct(struct nf_conn *ct,
2035 enum ip_conntrack_info ctinfo,
2036 const struct sk_buff *skb,
2040 /* Only update if this is not a fixed timeout */
2041 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
2044 /* If not in hash table, timer will not be active yet */
2045 if (nf_ct_is_confirmed(ct))
2046 extra_jiffies += nfct_time_stamp;
2048 if (READ_ONCE(ct->timeout) != extra_jiffies)
2049 WRITE_ONCE(ct->timeout, extra_jiffies);
2052 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
2054 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
2056 bool nf_ct_kill_acct(struct nf_conn *ct,
2057 enum ip_conntrack_info ctinfo,
2058 const struct sk_buff *skb)
2060 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
2062 return nf_ct_delete(ct, 0, 0);
2064 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
2066 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
2068 #include <linux/netfilter/nfnetlink.h>
2069 #include <linux/netfilter/nfnetlink_conntrack.h>
2070 #include <linux/mutex.h>
2072 /* Generic function for tcp/udp/sctp/dccp and alike. */
2073 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
2074 const struct nf_conntrack_tuple *tuple)
2076 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
2077 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
2078 goto nla_put_failure;
2084 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
2086 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
2087 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
2088 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
2090 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
2092 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
2093 struct nf_conntrack_tuple *t,
2096 if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) {
2097 if (!tb[CTA_PROTO_SRC_PORT])
2100 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
2103 if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) {
2104 if (!tb[CTA_PROTO_DST_PORT])
2107 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
2112 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
2114 unsigned int nf_ct_port_nlattr_tuple_size(void)
2116 static unsigned int size __read_mostly;
2119 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
2123 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
2126 /* Used by ipt_REJECT and ip6t_REJECT. */
2127 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
2130 enum ip_conntrack_info ctinfo;
2132 /* This ICMP is in reverse direction to the packet which caused it */
2133 ct = nf_ct_get(skb, &ctinfo);
2134 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
2135 ctinfo = IP_CT_RELATED_REPLY;
2137 ctinfo = IP_CT_RELATED;
2139 /* Attach to new skbuff, and increment count */
2140 nf_ct_set(nskb, ct, ctinfo);
2141 nf_conntrack_get(skb_nfct(nskb));
2144 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb,
2146 enum ip_conntrack_info ctinfo)
2148 struct nf_conntrack_tuple_hash *h;
2149 struct nf_conntrack_tuple tuple;
2150 struct nf_nat_hook *nat_hook;
2151 unsigned int status;
2156 l3num = nf_ct_l3num(ct);
2158 dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
2162 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
2163 l4num, net, &tuple))
2166 if (ct->status & IPS_SRC_NAT) {
2167 memcpy(tuple.src.u3.all,
2168 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all,
2169 sizeof(tuple.src.u3.all));
2171 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all;
2174 if (ct->status & IPS_DST_NAT) {
2175 memcpy(tuple.dst.u3.all,
2176 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all,
2177 sizeof(tuple.dst.u3.all));
2179 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all;
2182 h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple);
2186 /* Store status bits of the conntrack that is clashing to re-do NAT
2187 * mangling according to what it has been done already to this packet.
2189 status = ct->status;
2192 ct = nf_ct_tuplehash_to_ctrack(h);
2193 nf_ct_set(skb, ct, ctinfo);
2195 nat_hook = rcu_dereference(nf_nat_hook);
2199 if (status & IPS_SRC_NAT &&
2200 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC,
2201 IP_CT_DIR_ORIGINAL) == NF_DROP)
2204 if (status & IPS_DST_NAT &&
2205 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST,
2206 IP_CT_DIR_ORIGINAL) == NF_DROP)
2212 /* This packet is coming from userspace via nf_queue, complete the packet
2213 * processing after the helper invocation in nf_confirm().
2215 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct,
2216 enum ip_conntrack_info ctinfo)
2218 const struct nf_conntrack_helper *helper;
2219 const struct nf_conn_help *help;
2222 help = nfct_help(ct);
2226 helper = rcu_dereference(help->helper);
2227 if (!(helper->flags & NF_CT_HELPER_F_USERSPACE))
2230 switch (nf_ct_l3num(ct)) {
2232 protoff = skb_network_offset(skb) + ip_hdrlen(skb);
2234 #if IS_ENABLED(CONFIG_IPV6)
2235 case NFPROTO_IPV6: {
2239 pnum = ipv6_hdr(skb)->nexthdr;
2240 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
2242 if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
2251 if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
2252 !nf_is_loopback_packet(skb)) {
2253 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
2254 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
2259 /* We've seen it coming out the other side: confirm it */
2260 return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0;
2263 static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
2265 enum ip_conntrack_info ctinfo;
2269 ct = nf_ct_get(skb, &ctinfo);
2273 if (!nf_ct_is_confirmed(ct)) {
2274 err = __nf_conntrack_update(net, skb, ct, ctinfo);
2278 ct = nf_ct_get(skb, &ctinfo);
2281 return nf_confirm_cthelper(skb, ct, ctinfo);
2284 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
2285 const struct sk_buff *skb)
2287 const struct nf_conntrack_tuple *src_tuple;
2288 const struct nf_conntrack_tuple_hash *hash;
2289 struct nf_conntrack_tuple srctuple;
2290 enum ip_conntrack_info ctinfo;
2293 ct = nf_ct_get(skb, &ctinfo);
2295 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo));
2296 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2300 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
2301 NFPROTO_IPV4, dev_net(skb->dev),
2305 hash = nf_conntrack_find_get(dev_net(skb->dev),
2311 ct = nf_ct_tuplehash_to_ctrack(hash);
2312 src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir);
2313 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2319 /* Bring out ya dead! */
2320 static struct nf_conn *
2321 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
2322 void *data, unsigned int *bucket)
2324 struct nf_conntrack_tuple_hash *h;
2326 struct hlist_nulls_node *n;
2329 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
2330 struct hlist_nulls_head *hslot = &nf_conntrack_hash[*bucket];
2332 if (hlist_nulls_empty(hslot))
2335 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
2337 nf_conntrack_lock(lockp);
2338 hlist_nulls_for_each_entry(h, n, hslot, hnnode) {
2339 if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY)
2341 /* All nf_conn objects are added to hash table twice, one
2342 * for original direction tuple, once for the reply tuple.
2344 * Exception: In the IPS_NAT_CLASH case, only the reply
2345 * tuple is added (the original tuple already existed for
2346 * a different object).
2348 * We only need to call the iterator once for each
2349 * conntrack, so we just use the 'reply' direction
2350 * tuple while iterating.
2352 ct = nf_ct_tuplehash_to_ctrack(h);
2363 refcount_inc(&ct->ct_general.use);
2369 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data),
2370 void *data, u32 portid, int report)
2372 unsigned int bucket = 0;
2377 mutex_lock(&nf_conntrack_mutex);
2378 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
2379 /* Time to push up daises... */
2381 nf_ct_delete(ct, portid, report);
2385 mutex_unlock(&nf_conntrack_mutex);
2389 int (*iter)(struct nf_conn *i, void *data);
2394 static int iter_net_only(struct nf_conn *i, void *data)
2396 struct iter_data *d = data;
2398 if (!net_eq(d->net, nf_ct_net(i)))
2401 return d->iter(i, d->data);
2405 __nf_ct_unconfirmed_destroy(struct net *net)
2409 for_each_possible_cpu(cpu) {
2410 struct nf_conntrack_tuple_hash *h;
2411 struct hlist_nulls_node *n;
2412 struct ct_pcpu *pcpu;
2414 pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2416 spin_lock_bh(&pcpu->lock);
2417 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
2420 ct = nf_ct_tuplehash_to_ctrack(h);
2422 /* we cannot call iter() on unconfirmed list, the
2423 * owning cpu can reallocate ct->ext at any time.
2425 set_bit(IPS_DYING_BIT, &ct->status);
2427 spin_unlock_bh(&pcpu->lock);
2432 void nf_ct_unconfirmed_destroy(struct net *net)
2434 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2438 if (atomic_read(&cnet->count) > 0) {
2439 __nf_ct_unconfirmed_destroy(net);
2440 nf_queue_nf_hook_drop(net);
2444 EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy);
2446 void nf_ct_iterate_cleanup_net(struct net *net,
2447 int (*iter)(struct nf_conn *i, void *data),
2448 void *data, u32 portid, int report)
2450 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2455 if (atomic_read(&cnet->count) == 0)
2462 nf_ct_iterate_cleanup(iter_net_only, &d, portid, report);
2464 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net);
2467 * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table
2468 * @iter: callback to invoke for each conntrack
2469 * @data: data to pass to @iter
2471 * Like nf_ct_iterate_cleanup, but first marks conntracks on the
2472 * unconfirmed list as dying (so they will not be inserted into
2475 * Can only be called in module exit path.
2478 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
2482 down_read(&net_rwsem);
2484 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2486 if (atomic_read(&cnet->count) == 0)
2488 __nf_ct_unconfirmed_destroy(net);
2489 nf_queue_nf_hook_drop(net);
2491 up_read(&net_rwsem);
2493 /* Need to wait for netns cleanup worker to finish, if its
2494 * running -- it might have deleted a net namespace from
2495 * the global list, so our __nf_ct_unconfirmed_destroy() might
2496 * not have affected all namespaces.
2500 /* a conntrack could have been unlinked from unconfirmed list
2501 * before we grabbed pcpu lock in __nf_ct_unconfirmed_destroy().
2502 * This makes sure its inserted into conntrack table.
2506 nf_ct_iterate_cleanup(iter, data, 0, 0);
2508 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy);
2510 static int kill_all(struct nf_conn *i, void *data)
2512 return net_eq(nf_ct_net(i), data);
2515 void nf_conntrack_cleanup_start(void)
2517 conntrack_gc_work.exiting = true;
2518 RCU_INIT_POINTER(ip_ct_attach, NULL);
2521 void nf_conntrack_cleanup_end(void)
2523 RCU_INIT_POINTER(nf_ct_hook, NULL);
2524 cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2525 kvfree(nf_conntrack_hash);
2527 nf_conntrack_proto_fini();
2528 nf_conntrack_seqadj_fini();
2529 nf_conntrack_labels_fini();
2530 nf_conntrack_helper_fini();
2531 nf_conntrack_timeout_fini();
2532 nf_conntrack_ecache_fini();
2533 nf_conntrack_tstamp_fini();
2534 nf_conntrack_acct_fini();
2535 nf_conntrack_expect_fini();
2537 kmem_cache_destroy(nf_conntrack_cachep);
2541 * Mishearing the voices in his head, our hero wonders how he's
2542 * supposed to kill the mall.
2544 void nf_conntrack_cleanup_net(struct net *net)
2548 list_add(&net->exit_list, &single);
2549 nf_conntrack_cleanup_net_list(&single);
2552 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
2558 * This makes sure all current packets have passed through
2559 * netfilter framework. Roll on, two-stage module
2565 list_for_each_entry(net, net_exit_list, exit_list) {
2566 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2568 nf_ct_iterate_cleanup(kill_all, net, 0, 0);
2569 if (atomic_read(&cnet->count) != 0)
2574 goto i_see_dead_people;
2577 list_for_each_entry(net, net_exit_list, exit_list) {
2578 nf_conntrack_ecache_pernet_fini(net);
2579 nf_conntrack_expect_pernet_fini(net);
2580 free_percpu(net->ct.stat);
2581 free_percpu(net->ct.pcpu_lists);
2585 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
2587 struct hlist_nulls_head *hash;
2588 unsigned int nr_slots, i;
2590 if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
2593 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
2594 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
2596 hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL);
2599 for (i = 0; i < nr_slots; i++)
2600 INIT_HLIST_NULLS_HEAD(&hash[i], i);
2604 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
2606 int nf_conntrack_hash_resize(unsigned int hashsize)
2609 unsigned int old_size;
2610 struct hlist_nulls_head *hash, *old_hash;
2611 struct nf_conntrack_tuple_hash *h;
2617 hash = nf_ct_alloc_hashtable(&hashsize, 1);
2621 mutex_lock(&nf_conntrack_mutex);
2622 old_size = nf_conntrack_htable_size;
2623 if (old_size == hashsize) {
2624 mutex_unlock(&nf_conntrack_mutex);
2630 nf_conntrack_all_lock();
2631 write_seqcount_begin(&nf_conntrack_generation);
2633 /* Lookups in the old hash might happen in parallel, which means we
2634 * might get false negatives during connection lookup. New connections
2635 * created because of a false negative won't make it into the hash
2636 * though since that required taking the locks.
2639 for (i = 0; i < nf_conntrack_htable_size; i++) {
2640 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
2641 unsigned int zone_id;
2643 h = hlist_nulls_entry(nf_conntrack_hash[i].first,
2644 struct nf_conntrack_tuple_hash, hnnode);
2645 ct = nf_ct_tuplehash_to_ctrack(h);
2646 hlist_nulls_del_rcu(&h->hnnode);
2648 zone_id = nf_ct_zone_id(nf_ct_zone(ct), NF_CT_DIRECTION(h));
2649 bucket = __hash_conntrack(nf_ct_net(ct),
2650 &h->tuple, zone_id, hashsize);
2651 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
2654 old_size = nf_conntrack_htable_size;
2655 old_hash = nf_conntrack_hash;
2657 nf_conntrack_hash = hash;
2658 nf_conntrack_htable_size = hashsize;
2660 write_seqcount_end(&nf_conntrack_generation);
2661 nf_conntrack_all_unlock();
2664 mutex_unlock(&nf_conntrack_mutex);
2671 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp)
2673 unsigned int hashsize;
2676 if (current->nsproxy->net_ns != &init_net)
2679 /* On boot, we can set this without any fancy locking. */
2680 if (!nf_conntrack_hash)
2681 return param_set_uint(val, kp);
2683 rc = kstrtouint(val, 0, &hashsize);
2687 return nf_conntrack_hash_resize(hashsize);
2690 static __always_inline unsigned int total_extension_size(void)
2692 /* remember to add new extensions below */
2693 BUILD_BUG_ON(NF_CT_EXT_NUM > 9);
2695 return sizeof(struct nf_ct_ext) +
2696 sizeof(struct nf_conn_help)
2697 #if IS_ENABLED(CONFIG_NF_NAT)
2698 + sizeof(struct nf_conn_nat)
2700 + sizeof(struct nf_conn_seqadj)
2701 + sizeof(struct nf_conn_acct)
2702 #ifdef CONFIG_NF_CONNTRACK_EVENTS
2703 + sizeof(struct nf_conntrack_ecache)
2705 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
2706 + sizeof(struct nf_conn_tstamp)
2708 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
2709 + sizeof(struct nf_conn_timeout)
2711 #ifdef CONFIG_NF_CONNTRACK_LABELS
2712 + sizeof(struct nf_conn_labels)
2714 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
2715 + sizeof(struct nf_conn_synproxy)
2720 int nf_conntrack_init_start(void)
2722 unsigned long nr_pages = totalram_pages();
2727 /* struct nf_ct_ext uses u8 to store offsets/size */
2728 BUILD_BUG_ON(total_extension_size() > 255u);
2730 seqcount_spinlock_init(&nf_conntrack_generation,
2731 &nf_conntrack_locks_all_lock);
2733 for (i = 0; i < CONNTRACK_LOCKS; i++)
2734 spin_lock_init(&nf_conntrack_locks[i]);
2736 if (!nf_conntrack_htable_size) {
2737 nf_conntrack_htable_size
2738 = (((nr_pages << PAGE_SHIFT) / 16384)
2739 / sizeof(struct hlist_head));
2740 if (BITS_PER_LONG >= 64 &&
2741 nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
2742 nf_conntrack_htable_size = 262144;
2743 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
2744 nf_conntrack_htable_size = 65536;
2746 if (nf_conntrack_htable_size < 1024)
2747 nf_conntrack_htable_size = 1024;
2748 /* Use a max. factor of one by default to keep the average
2749 * hash chain length at 2 entries. Each entry has to be added
2750 * twice (once for original direction, once for reply).
2751 * When a table size is given we use the old value of 8 to
2752 * avoid implicit reduction of the max entries setting.
2757 nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
2758 if (!nf_conntrack_hash)
2761 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
2763 nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
2764 sizeof(struct nf_conn),
2766 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
2767 if (!nf_conntrack_cachep)
2770 ret = nf_conntrack_expect_init();
2774 ret = nf_conntrack_acct_init();
2778 ret = nf_conntrack_tstamp_init();
2782 ret = nf_conntrack_ecache_init();
2786 ret = nf_conntrack_timeout_init();
2790 ret = nf_conntrack_helper_init();
2794 ret = nf_conntrack_labels_init();
2798 ret = nf_conntrack_seqadj_init();
2802 ret = nf_conntrack_proto_init();
2806 conntrack_gc_work_init(&conntrack_gc_work);
2807 queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ);
2812 nf_conntrack_seqadj_fini();
2814 nf_conntrack_labels_fini();
2816 nf_conntrack_helper_fini();
2818 nf_conntrack_timeout_fini();
2820 nf_conntrack_ecache_fini();
2822 nf_conntrack_tstamp_fini();
2824 nf_conntrack_acct_fini();
2826 nf_conntrack_expect_fini();
2828 kmem_cache_destroy(nf_conntrack_cachep);
2830 kvfree(nf_conntrack_hash);
2834 static struct nf_ct_hook nf_conntrack_hook = {
2835 .update = nf_conntrack_update,
2836 .destroy = nf_ct_destroy,
2837 .get_tuple_skb = nf_conntrack_get_tuple_skb,
2840 void nf_conntrack_init_end(void)
2842 /* For use by REJECT target */
2843 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
2844 RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook);
2848 * We need to use special "null" values, not used in hash table
2850 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0)
2851 #define DYING_NULLS_VAL ((1<<30)+1)
2853 int nf_conntrack_init_net(struct net *net)
2855 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2859 BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER);
2860 BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS);
2861 atomic_set(&cnet->count, 0);
2863 net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
2864 if (!net->ct.pcpu_lists)
2867 for_each_possible_cpu(cpu) {
2868 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2870 spin_lock_init(&pcpu->lock);
2871 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
2872 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
2875 net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
2877 goto err_pcpu_lists;
2879 ret = nf_conntrack_expect_pernet_init(net);
2883 nf_conntrack_acct_pernet_init(net);
2884 nf_conntrack_tstamp_pernet_init(net);
2885 nf_conntrack_ecache_pernet_init(net);
2886 nf_conntrack_helper_pernet_init(net);
2887 nf_conntrack_proto_pernet_init(net);
2892 free_percpu(net->ct.stat);
2894 free_percpu(net->ct.pcpu_lists);