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_bpf.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_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
;
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 /* serialize hash resizes and nf_ct_iterate_cleanup */
80 static DEFINE_MUTEX(nf_conntrack_mutex
);
82 #define GC_SCAN_INTERVAL_MAX (60ul * HZ)
83 #define GC_SCAN_INTERVAL_MIN (1ul * HZ)
85 /* clamp timeouts to this value (TCP unacked) */
86 #define GC_SCAN_INTERVAL_CLAMP (300ul * HZ)
88 /* large initial bias so that we don't scan often just because we have
89 * three entries with a 1s timeout.
91 #define GC_SCAN_INTERVAL_INIT INT_MAX
93 #define GC_SCAN_MAX_DURATION msecs_to_jiffies(10)
94 #define GC_SCAN_EXPIRED_MAX (64000u / HZ)
96 #define MIN_CHAINLEN 8u
97 #define MAX_CHAINLEN (32u - MIN_CHAINLEN)
99 static struct conntrack_gc_work conntrack_gc_work
;
101 void nf_conntrack_lock(spinlock_t
*lock
) __acquires(lock
)
103 /* 1) Acquire the lock */
106 /* 2) read nf_conntrack_locks_all, with ACQUIRE semantics
107 * It pairs with the smp_store_release() in nf_conntrack_all_unlock()
109 if (likely(smp_load_acquire(&nf_conntrack_locks_all
) == false))
112 /* fast path failed, unlock */
115 /* Slow path 1) get global lock */
116 spin_lock(&nf_conntrack_locks_all_lock
);
118 /* Slow path 2) get the lock we want */
121 /* Slow path 3) release the global lock */
122 spin_unlock(&nf_conntrack_locks_all_lock
);
124 EXPORT_SYMBOL_GPL(nf_conntrack_lock
);
126 static void nf_conntrack_double_unlock(unsigned int h1
, unsigned int h2
)
128 h1
%= CONNTRACK_LOCKS
;
129 h2
%= CONNTRACK_LOCKS
;
130 spin_unlock(&nf_conntrack_locks
[h1
]);
132 spin_unlock(&nf_conntrack_locks
[h2
]);
135 /* return true if we need to recompute hashes (in case hash table was resized) */
136 static bool nf_conntrack_double_lock(struct net
*net
, unsigned int h1
,
137 unsigned int h2
, unsigned int sequence
)
139 h1
%= CONNTRACK_LOCKS
;
140 h2
%= CONNTRACK_LOCKS
;
142 nf_conntrack_lock(&nf_conntrack_locks
[h1
]);
144 spin_lock_nested(&nf_conntrack_locks
[h2
],
145 SINGLE_DEPTH_NESTING
);
147 nf_conntrack_lock(&nf_conntrack_locks
[h2
]);
148 spin_lock_nested(&nf_conntrack_locks
[h1
],
149 SINGLE_DEPTH_NESTING
);
151 if (read_seqcount_retry(&nf_conntrack_generation
, sequence
)) {
152 nf_conntrack_double_unlock(h1
, h2
);
158 static void nf_conntrack_all_lock(void)
159 __acquires(&nf_conntrack_locks_all_lock
)
163 spin_lock(&nf_conntrack_locks_all_lock
);
165 /* For nf_contrack_locks_all, only the latest time when another
166 * CPU will see an update is controlled, by the "release" of the
168 * The earliest time is not controlled, an thus KCSAN could detect
169 * a race when nf_conntract_lock() reads the variable.
170 * WRITE_ONCE() is used to ensure the compiler will not
171 * optimize the write.
173 WRITE_ONCE(nf_conntrack_locks_all
, true);
175 for (i
= 0; i
< CONNTRACK_LOCKS
; i
++) {
176 spin_lock(&nf_conntrack_locks
[i
]);
178 /* This spin_unlock provides the "release" to ensure that
179 * nf_conntrack_locks_all==true is visible to everyone that
180 * acquired spin_lock(&nf_conntrack_locks[]).
182 spin_unlock(&nf_conntrack_locks
[i
]);
186 static void nf_conntrack_all_unlock(void)
187 __releases(&nf_conntrack_locks_all_lock
)
189 /* All prior stores must be complete before we clear
190 * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
191 * might observe the false value but not the entire
193 * It pairs with the smp_load_acquire() in nf_conntrack_lock()
195 smp_store_release(&nf_conntrack_locks_all
, false);
196 spin_unlock(&nf_conntrack_locks_all_lock
);
199 unsigned int nf_conntrack_htable_size __read_mostly
;
200 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size
);
202 unsigned int nf_conntrack_max __read_mostly
;
203 EXPORT_SYMBOL_GPL(nf_conntrack_max
);
204 seqcount_spinlock_t nf_conntrack_generation __read_mostly
;
205 static siphash_aligned_key_t nf_conntrack_hash_rnd
;
207 static u32
hash_conntrack_raw(const struct nf_conntrack_tuple
*tuple
,
209 const struct net
*net
)
212 struct nf_conntrack_man src
;
213 union nf_inet_addr dst_addr
;
218 } __aligned(SIPHASH_ALIGNMENT
) combined
;
220 get_random_once(&nf_conntrack_hash_rnd
, sizeof(nf_conntrack_hash_rnd
));
222 memset(&combined
, 0, sizeof(combined
));
224 /* The direction must be ignored, so handle usable members manually. */
225 combined
.src
= tuple
->src
;
226 combined
.dst_addr
= tuple
->dst
.u3
;
227 combined
.zone
= zoneid
;
228 combined
.net_mix
= net_hash_mix(net
);
229 combined
.dport
= (__force __u16
)tuple
->dst
.u
.all
;
230 combined
.proto
= tuple
->dst
.protonum
;
232 return (u32
)siphash(&combined
, sizeof(combined
), &nf_conntrack_hash_rnd
);
235 static u32
scale_hash(u32 hash
)
237 return reciprocal_scale(hash
, nf_conntrack_htable_size
);
240 static u32
__hash_conntrack(const struct net
*net
,
241 const struct nf_conntrack_tuple
*tuple
,
245 return reciprocal_scale(hash_conntrack_raw(tuple
, zoneid
, net
), size
);
248 static u32
hash_conntrack(const struct net
*net
,
249 const struct nf_conntrack_tuple
*tuple
,
252 return scale_hash(hash_conntrack_raw(tuple
, zoneid
, net
));
255 static bool nf_ct_get_tuple_ports(const struct sk_buff
*skb
,
256 unsigned int dataoff
,
257 struct nf_conntrack_tuple
*tuple
)
261 } _inet_hdr
, *inet_hdr
;
263 /* Actually only need first 4 bytes to get ports. */
264 inet_hdr
= skb_header_pointer(skb
, dataoff
, sizeof(_inet_hdr
), &_inet_hdr
);
268 tuple
->src
.u
.udp
.port
= inet_hdr
->sport
;
269 tuple
->dst
.u
.udp
.port
= inet_hdr
->dport
;
274 nf_ct_get_tuple(const struct sk_buff
*skb
,
276 unsigned int dataoff
,
280 struct nf_conntrack_tuple
*tuple
)
286 memset(tuple
, 0, sizeof(*tuple
));
288 tuple
->src
.l3num
= l3num
;
291 nhoff
+= offsetof(struct iphdr
, saddr
);
292 size
= 2 * sizeof(__be32
);
295 nhoff
+= offsetof(struct ipv6hdr
, saddr
);
296 size
= sizeof(_addrs
);
302 ap
= skb_header_pointer(skb
, nhoff
, size
, _addrs
);
308 tuple
->src
.u3
.ip
= ap
[0];
309 tuple
->dst
.u3
.ip
= ap
[1];
312 memcpy(tuple
->src
.u3
.ip6
, ap
, sizeof(tuple
->src
.u3
.ip6
));
313 memcpy(tuple
->dst
.u3
.ip6
, ap
+ 4, sizeof(tuple
->dst
.u3
.ip6
));
317 tuple
->dst
.protonum
= protonum
;
318 tuple
->dst
.dir
= IP_CT_DIR_ORIGINAL
;
321 #if IS_ENABLED(CONFIG_IPV6)
323 return icmpv6_pkt_to_tuple(skb
, dataoff
, net
, tuple
);
326 return icmp_pkt_to_tuple(skb
, dataoff
, net
, tuple
);
327 #ifdef CONFIG_NF_CT_PROTO_GRE
329 return gre_pkt_to_tuple(skb
, dataoff
, net
, tuple
);
332 case IPPROTO_UDP
: /* fallthrough */
333 return nf_ct_get_tuple_ports(skb
, dataoff
, tuple
);
334 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
335 case IPPROTO_UDPLITE
:
336 return nf_ct_get_tuple_ports(skb
, dataoff
, tuple
);
338 #ifdef CONFIG_NF_CT_PROTO_SCTP
340 return nf_ct_get_tuple_ports(skb
, dataoff
, tuple
);
342 #ifdef CONFIG_NF_CT_PROTO_DCCP
344 return nf_ct_get_tuple_ports(skb
, dataoff
, tuple
);
353 static int ipv4_get_l4proto(const struct sk_buff
*skb
, unsigned int nhoff
,
357 const struct iphdr
*iph
;
360 iph
= skb_header_pointer(skb
, nhoff
, sizeof(_iph
), &_iph
);
364 /* Conntrack defragments packets, we might still see fragments
365 * inside ICMP packets though.
367 if (iph
->frag_off
& htons(IP_OFFSET
))
370 dataoff
= nhoff
+ (iph
->ihl
<< 2);
371 *protonum
= iph
->protocol
;
373 /* Check bogus IP headers */
374 if (dataoff
> skb
->len
) {
375 pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
376 nhoff
, iph
->ihl
<< 2, skb
->len
);
382 #if IS_ENABLED(CONFIG_IPV6)
383 static int ipv6_get_l4proto(const struct sk_buff
*skb
, unsigned int nhoff
,
387 unsigned int extoff
= nhoff
+ sizeof(struct ipv6hdr
);
391 if (skb_copy_bits(skb
, nhoff
+ offsetof(struct ipv6hdr
, nexthdr
),
392 &nexthdr
, sizeof(nexthdr
)) != 0) {
393 pr_debug("can't get nexthdr\n");
396 protoff
= ipv6_skip_exthdr(skb
, extoff
, &nexthdr
, &frag_off
);
398 * (protoff == skb->len) means the packet has not data, just
399 * IPv6 and possibly extensions headers, but it is tracked anyway
401 if (protoff
< 0 || (frag_off
& htons(~0x7)) != 0) {
402 pr_debug("can't find proto in pkt\n");
411 static int get_l4proto(const struct sk_buff
*skb
,
412 unsigned int nhoff
, u8 pf
, u8
*l4num
)
416 return ipv4_get_l4proto(skb
, nhoff
, l4num
);
417 #if IS_ENABLED(CONFIG_IPV6)
419 return ipv6_get_l4proto(skb
, nhoff
, l4num
);
428 bool nf_ct_get_tuplepr(const struct sk_buff
*skb
, unsigned int nhoff
,
430 struct net
*net
, struct nf_conntrack_tuple
*tuple
)
435 protoff
= get_l4proto(skb
, nhoff
, l3num
, &protonum
);
439 return nf_ct_get_tuple(skb
, nhoff
, protoff
, l3num
, protonum
, net
, tuple
);
441 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr
);
444 nf_ct_invert_tuple(struct nf_conntrack_tuple
*inverse
,
445 const struct nf_conntrack_tuple
*orig
)
447 memset(inverse
, 0, sizeof(*inverse
));
449 inverse
->src
.l3num
= orig
->src
.l3num
;
451 switch (orig
->src
.l3num
) {
453 inverse
->src
.u3
.ip
= orig
->dst
.u3
.ip
;
454 inverse
->dst
.u3
.ip
= orig
->src
.u3
.ip
;
457 inverse
->src
.u3
.in6
= orig
->dst
.u3
.in6
;
458 inverse
->dst
.u3
.in6
= orig
->src
.u3
.in6
;
464 inverse
->dst
.dir
= !orig
->dst
.dir
;
466 inverse
->dst
.protonum
= orig
->dst
.protonum
;
468 switch (orig
->dst
.protonum
) {
470 return nf_conntrack_invert_icmp_tuple(inverse
, orig
);
471 #if IS_ENABLED(CONFIG_IPV6)
473 return nf_conntrack_invert_icmpv6_tuple(inverse
, orig
);
477 inverse
->src
.u
.all
= orig
->dst
.u
.all
;
478 inverse
->dst
.u
.all
= orig
->src
.u
.all
;
481 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple
);
483 /* Generate a almost-unique pseudo-id for a given conntrack.
485 * intentionally doesn't re-use any of the seeds used for hash
486 * table location, we assume id gets exposed to userspace.
488 * Following nf_conn items do not change throughout lifetime
492 * 2. nf_conn->master address (normally NULL)
493 * 3. the associated net namespace
494 * 4. the original direction tuple
496 u32
nf_ct_get_id(const struct nf_conn
*ct
)
498 static siphash_aligned_key_t ct_id_seed
;
499 unsigned long a
, b
, c
, d
;
501 net_get_random_once(&ct_id_seed
, sizeof(ct_id_seed
));
503 a
= (unsigned long)ct
;
504 b
= (unsigned long)ct
->master
;
505 c
= (unsigned long)nf_ct_net(ct
);
506 d
= (unsigned long)siphash(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
507 sizeof(ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
),
510 return siphash_4u64((u64
)a
, (u64
)b
, (u64
)c
, (u64
)d
, &ct_id_seed
);
512 return siphash_4u32((u32
)a
, (u32
)b
, (u32
)c
, (u32
)d
, &ct_id_seed
);
515 EXPORT_SYMBOL_GPL(nf_ct_get_id
);
518 clean_from_lists(struct nf_conn
*ct
)
520 pr_debug("clean_from_lists(%p)\n", ct
);
521 hlist_nulls_del_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
);
522 hlist_nulls_del_rcu(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnnode
);
524 /* Destroy all pending expectations */
525 nf_ct_remove_expectations(ct
);
528 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
530 /* Released via nf_ct_destroy() */
531 struct nf_conn
*nf_ct_tmpl_alloc(struct net
*net
,
532 const struct nf_conntrack_zone
*zone
,
535 struct nf_conn
*tmpl
, *p
;
537 if (ARCH_KMALLOC_MINALIGN
<= NFCT_INFOMASK
) {
538 tmpl
= kzalloc(sizeof(*tmpl
) + NFCT_INFOMASK
, flags
);
543 tmpl
= (struct nf_conn
*)NFCT_ALIGN((unsigned long)p
);
545 tmpl
= (struct nf_conn
*)NFCT_ALIGN((unsigned long)p
);
546 tmpl
->proto
.tmpl_padto
= (char *)tmpl
- (char *)p
;
549 tmpl
= kzalloc(sizeof(*tmpl
), flags
);
554 tmpl
->status
= IPS_TEMPLATE
;
555 write_pnet(&tmpl
->ct_net
, net
);
556 nf_ct_zone_add(tmpl
, zone
);
557 refcount_set(&tmpl
->ct_general
.use
, 1);
561 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc
);
563 void nf_ct_tmpl_free(struct nf_conn
*tmpl
)
567 if (ARCH_KMALLOC_MINALIGN
<= NFCT_INFOMASK
)
568 kfree((char *)tmpl
- tmpl
->proto
.tmpl_padto
);
572 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free
);
574 static void destroy_gre_conntrack(struct nf_conn
*ct
)
576 #ifdef CONFIG_NF_CT_PROTO_GRE
577 struct nf_conn
*master
= ct
->master
;
580 nf_ct_gre_keymap_destroy(master
);
584 void nf_ct_destroy(struct nf_conntrack
*nfct
)
586 struct nf_conn
*ct
= (struct nf_conn
*)nfct
;
588 pr_debug("%s(%p)\n", __func__
, ct
);
589 WARN_ON(refcount_read(&nfct
->use
) != 0);
591 if (unlikely(nf_ct_is_template(ct
))) {
596 if (unlikely(nf_ct_protonum(ct
) == IPPROTO_GRE
))
597 destroy_gre_conntrack(ct
);
599 /* Expectations will have been removed in clean_from_lists,
600 * except TFTP can create an expectation on the first packet,
601 * before connection is in the list, so we need to clean here,
604 nf_ct_remove_expectations(ct
);
607 nf_ct_put(ct
->master
);
609 pr_debug("%s: returning ct=%p to slab\n", __func__
, ct
);
610 nf_conntrack_free(ct
);
612 EXPORT_SYMBOL(nf_ct_destroy
);
614 static void __nf_ct_delete_from_lists(struct nf_conn
*ct
)
616 struct net
*net
= nf_ct_net(ct
);
617 unsigned int hash
, reply_hash
;
618 unsigned int sequence
;
621 sequence
= read_seqcount_begin(&nf_conntrack_generation
);
622 hash
= hash_conntrack(net
,
623 &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
624 nf_ct_zone_id(nf_ct_zone(ct
), IP_CT_DIR_ORIGINAL
));
625 reply_hash
= hash_conntrack(net
,
626 &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
627 nf_ct_zone_id(nf_ct_zone(ct
), IP_CT_DIR_REPLY
));
628 } while (nf_conntrack_double_lock(net
, hash
, reply_hash
, sequence
));
630 clean_from_lists(ct
);
631 nf_conntrack_double_unlock(hash
, reply_hash
);
634 static void nf_ct_delete_from_lists(struct nf_conn
*ct
)
636 nf_ct_helper_destroy(ct
);
639 __nf_ct_delete_from_lists(ct
);
644 static void nf_ct_add_to_ecache_list(struct nf_conn
*ct
)
646 #ifdef CONFIG_NF_CONNTRACK_EVENTS
647 struct nf_conntrack_net
*cnet
= nf_ct_pernet(nf_ct_net(ct
));
649 spin_lock(&cnet
->ecache
.dying_lock
);
650 hlist_nulls_add_head_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
,
651 &cnet
->ecache
.dying_list
);
652 spin_unlock(&cnet
->ecache
.dying_lock
);
656 bool nf_ct_delete(struct nf_conn
*ct
, u32 portid
, int report
)
658 struct nf_conn_tstamp
*tstamp
;
661 if (test_and_set_bit(IPS_DYING_BIT
, &ct
->status
))
664 tstamp
= nf_conn_tstamp_find(ct
);
666 s32 timeout
= READ_ONCE(ct
->timeout
) - nfct_time_stamp
;
668 tstamp
->stop
= ktime_get_real_ns();
670 tstamp
->stop
-= jiffies_to_nsecs(-timeout
);
673 if (nf_conntrack_event_report(IPCT_DESTROY
, ct
,
674 portid
, report
) < 0) {
675 /* destroy event was not delivered. nf_ct_put will
676 * be done by event cache worker on redelivery.
678 nf_ct_helper_destroy(ct
);
680 __nf_ct_delete_from_lists(ct
);
681 nf_ct_add_to_ecache_list(ct
);
684 nf_conntrack_ecache_work(nf_ct_net(ct
), NFCT_ECACHE_DESTROY_FAIL
);
689 if (nf_conntrack_ecache_dwork_pending(net
))
690 nf_conntrack_ecache_work(net
, NFCT_ECACHE_DESTROY_SENT
);
691 nf_ct_delete_from_lists(ct
);
695 EXPORT_SYMBOL_GPL(nf_ct_delete
);
698 nf_ct_key_equal(struct nf_conntrack_tuple_hash
*h
,
699 const struct nf_conntrack_tuple
*tuple
,
700 const struct nf_conntrack_zone
*zone
,
701 const struct net
*net
)
703 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
705 /* A conntrack can be recreated with the equal tuple,
706 * so we need to check that the conntrack is confirmed
708 return nf_ct_tuple_equal(tuple
, &h
->tuple
) &&
709 nf_ct_zone_equal(ct
, zone
, NF_CT_DIRECTION(h
)) &&
710 nf_ct_is_confirmed(ct
) &&
711 net_eq(net
, nf_ct_net(ct
));
715 nf_ct_match(const struct nf_conn
*ct1
, const struct nf_conn
*ct2
)
717 return nf_ct_tuple_equal(&ct1
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
718 &ct2
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
) &&
719 nf_ct_tuple_equal(&ct1
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
720 &ct2
->tuplehash
[IP_CT_DIR_REPLY
].tuple
) &&
721 nf_ct_zone_equal(ct1
, nf_ct_zone(ct2
), IP_CT_DIR_ORIGINAL
) &&
722 nf_ct_zone_equal(ct1
, nf_ct_zone(ct2
), IP_CT_DIR_REPLY
) &&
723 net_eq(nf_ct_net(ct1
), nf_ct_net(ct2
));
726 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
727 static void nf_ct_gc_expired(struct nf_conn
*ct
)
729 if (!refcount_inc_not_zero(&ct
->ct_general
.use
))
732 if (nf_ct_should_gc(ct
))
740 * - Caller must take a reference on returned object
741 * and recheck nf_ct_tuple_equal(tuple, &h->tuple)
743 static struct nf_conntrack_tuple_hash
*
744 ____nf_conntrack_find(struct net
*net
, const struct nf_conntrack_zone
*zone
,
745 const struct nf_conntrack_tuple
*tuple
, u32 hash
)
747 struct nf_conntrack_tuple_hash
*h
;
748 struct hlist_nulls_head
*ct_hash
;
749 struct hlist_nulls_node
*n
;
750 unsigned int bucket
, hsize
;
753 nf_conntrack_get_ht(&ct_hash
, &hsize
);
754 bucket
= reciprocal_scale(hash
, hsize
);
756 hlist_nulls_for_each_entry_rcu(h
, n
, &ct_hash
[bucket
], hnnode
) {
759 ct
= nf_ct_tuplehash_to_ctrack(h
);
760 if (nf_ct_is_expired(ct
)) {
761 nf_ct_gc_expired(ct
);
765 if (nf_ct_key_equal(h
, tuple
, zone
, net
))
769 * if the nulls value we got at the end of this lookup is
770 * not the expected one, we must restart lookup.
771 * We probably met an item that was moved to another chain.
773 if (get_nulls_value(n
) != bucket
) {
774 NF_CT_STAT_INC_ATOMIC(net
, search_restart
);
781 /* Find a connection corresponding to a tuple. */
782 static struct nf_conntrack_tuple_hash
*
783 __nf_conntrack_find_get(struct net
*net
, const struct nf_conntrack_zone
*zone
,
784 const struct nf_conntrack_tuple
*tuple
, u32 hash
)
786 struct nf_conntrack_tuple_hash
*h
;
791 h
= ____nf_conntrack_find(net
, zone
, tuple
, hash
);
793 /* We have a candidate that matches the tuple we're interested
794 * in, try to obtain a reference and re-check tuple
796 ct
= nf_ct_tuplehash_to_ctrack(h
);
797 if (likely(refcount_inc_not_zero(&ct
->ct_general
.use
))) {
798 if (likely(nf_ct_key_equal(h
, tuple
, zone
, net
)))
801 /* TYPESAFE_BY_RCU recycled the candidate */
813 struct nf_conntrack_tuple_hash
*
814 nf_conntrack_find_get(struct net
*net
, const struct nf_conntrack_zone
*zone
,
815 const struct nf_conntrack_tuple
*tuple
)
817 unsigned int rid
, zone_id
= nf_ct_zone_id(zone
, IP_CT_DIR_ORIGINAL
);
818 struct nf_conntrack_tuple_hash
*thash
;
820 thash
= __nf_conntrack_find_get(net
, zone
, tuple
,
821 hash_conntrack_raw(tuple
, zone_id
, net
));
826 rid
= nf_ct_zone_id(zone
, IP_CT_DIR_REPLY
);
828 return __nf_conntrack_find_get(net
, zone
, tuple
,
829 hash_conntrack_raw(tuple
, rid
, net
));
832 EXPORT_SYMBOL_GPL(nf_conntrack_find_get
);
834 static void __nf_conntrack_hash_insert(struct nf_conn
*ct
,
836 unsigned int reply_hash
)
838 hlist_nulls_add_head_rcu(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
,
839 &nf_conntrack_hash
[hash
]);
840 hlist_nulls_add_head_rcu(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnnode
,
841 &nf_conntrack_hash
[reply_hash
]);
844 static bool nf_ct_ext_valid_pre(const struct nf_ct_ext
*ext
)
846 /* if ext->gen_id is not equal to nf_conntrack_ext_genid, some extensions
847 * may contain stale pointers to e.g. helper that has been removed.
849 * The helper can't clear this because the nf_conn object isn't in
850 * any hash and synchronize_rcu() isn't enough because associated skb
851 * might sit in a queue.
853 return !ext
|| ext
->gen_id
== atomic_read(&nf_conntrack_ext_genid
);
856 static bool nf_ct_ext_valid_post(struct nf_ct_ext
*ext
)
861 if (ext
->gen_id
!= atomic_read(&nf_conntrack_ext_genid
))
864 /* inserted into conntrack table, nf_ct_iterate_cleanup()
865 * will find it. Disable nf_ct_ext_find() id check.
867 WRITE_ONCE(ext
->gen_id
, 0);
872 nf_conntrack_hash_check_insert(struct nf_conn
*ct
)
874 const struct nf_conntrack_zone
*zone
;
875 struct net
*net
= nf_ct_net(ct
);
876 unsigned int hash
, reply_hash
;
877 struct nf_conntrack_tuple_hash
*h
;
878 struct hlist_nulls_node
*n
;
879 unsigned int max_chainlen
;
880 unsigned int chainlen
= 0;
881 unsigned int sequence
;
884 zone
= nf_ct_zone(ct
);
886 if (!nf_ct_ext_valid_pre(ct
->ext
)) {
887 NF_CT_STAT_INC(net
, insert_failed
);
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
);
932 if (!nf_ct_ext_valid_post(ct
->ext
)) {
934 NF_CT_STAT_INC(net
, drop
);
940 NF_CT_STAT_INC(net
, chaintoolong
);
943 nf_conntrack_double_unlock(hash
, reply_hash
);
947 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert
);
949 void nf_ct_acct_add(struct nf_conn
*ct
, u32 dir
, unsigned int packets
,
952 struct nf_conn_acct
*acct
;
954 acct
= nf_conn_acct_find(ct
);
956 struct nf_conn_counter
*counter
= acct
->counter
;
958 atomic64_add(packets
, &counter
[dir
].packets
);
959 atomic64_add(bytes
, &counter
[dir
].bytes
);
962 EXPORT_SYMBOL_GPL(nf_ct_acct_add
);
964 static void nf_ct_acct_merge(struct nf_conn
*ct
, enum ip_conntrack_info ctinfo
,
965 const struct nf_conn
*loser_ct
)
967 struct nf_conn_acct
*acct
;
969 acct
= nf_conn_acct_find(loser_ct
);
971 struct nf_conn_counter
*counter
= acct
->counter
;
974 /* u32 should be fine since we must have seen one packet. */
975 bytes
= atomic64_read(&counter
[CTINFO2DIR(ctinfo
)].bytes
);
976 nf_ct_acct_update(ct
, CTINFO2DIR(ctinfo
), bytes
);
980 static void __nf_conntrack_insert_prepare(struct nf_conn
*ct
)
982 struct nf_conn_tstamp
*tstamp
;
984 refcount_inc(&ct
->ct_general
.use
);
986 /* set conntrack timestamp, if enabled. */
987 tstamp
= nf_conn_tstamp_find(ct
);
989 tstamp
->start
= ktime_get_real_ns();
992 /* caller must hold locks to prevent concurrent changes */
993 static int __nf_ct_resolve_clash(struct sk_buff
*skb
,
994 struct nf_conntrack_tuple_hash
*h
)
996 /* This is the conntrack entry already in hashes that won race. */
997 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
998 enum ip_conntrack_info ctinfo
;
999 struct nf_conn
*loser_ct
;
1001 loser_ct
= nf_ct_get(skb
, &ctinfo
);
1003 if (nf_ct_is_dying(ct
))
1006 if (((ct
->status
& IPS_NAT_DONE_MASK
) == 0) ||
1007 nf_ct_match(ct
, loser_ct
)) {
1008 struct net
*net
= nf_ct_net(ct
);
1010 nf_conntrack_get(&ct
->ct_general
);
1012 nf_ct_acct_merge(ct
, ctinfo
, loser_ct
);
1013 nf_ct_put(loser_ct
);
1014 nf_ct_set(skb
, ct
, ctinfo
);
1016 NF_CT_STAT_INC(net
, clash_resolve
);
1024 * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry
1026 * @skb: skb that causes the collision
1027 * @repl_idx: hash slot for reply direction
1029 * Called when origin or reply direction had a clash.
1030 * The skb can be handled without packet drop provided the reply direction
1031 * is unique or there the existing entry has the identical tuple in both
1034 * Caller must hold conntrack table locks to prevent concurrent updates.
1036 * Returns NF_DROP if the clash could not be handled.
1038 static int nf_ct_resolve_clash_harder(struct sk_buff
*skb
, u32 repl_idx
)
1040 struct nf_conn
*loser_ct
= (struct nf_conn
*)skb_nfct(skb
);
1041 const struct nf_conntrack_zone
*zone
;
1042 struct nf_conntrack_tuple_hash
*h
;
1043 struct hlist_nulls_node
*n
;
1046 zone
= nf_ct_zone(loser_ct
);
1047 net
= nf_ct_net(loser_ct
);
1049 /* Reply direction must never result in a clash, unless both origin
1050 * and reply tuples are identical.
1052 hlist_nulls_for_each_entry(h
, n
, &nf_conntrack_hash
[repl_idx
], hnnode
) {
1053 if (nf_ct_key_equal(h
,
1054 &loser_ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
1056 return __nf_ct_resolve_clash(skb
, h
);
1059 /* We want the clashing entry to go away real soon: 1 second timeout. */
1060 WRITE_ONCE(loser_ct
->timeout
, nfct_time_stamp
+ HZ
);
1062 /* IPS_NAT_CLASH removes the entry automatically on the first
1063 * reply. Also prevents UDP tracker from moving the entry to
1064 * ASSURED state, i.e. the entry can always be evicted under
1067 loser_ct
->status
|= IPS_FIXED_TIMEOUT
| IPS_NAT_CLASH
;
1069 __nf_conntrack_insert_prepare(loser_ct
);
1071 /* fake add for ORIGINAL dir: we want lookups to only find the entry
1072 * already in the table. This also hides the clashing entry from
1073 * ctnetlink iteration, i.e. conntrack -L won't show them.
1075 hlist_nulls_add_fake(&loser_ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
);
1077 hlist_nulls_add_head_rcu(&loser_ct
->tuplehash
[IP_CT_DIR_REPLY
].hnnode
,
1078 &nf_conntrack_hash
[repl_idx
]);
1080 NF_CT_STAT_INC(net
, clash_resolve
);
1085 * nf_ct_resolve_clash - attempt to handle clash without packet drop
1087 * @skb: skb that causes the clash
1088 * @h: tuplehash of the clashing entry already in table
1089 * @reply_hash: hash slot for reply direction
1091 * A conntrack entry can be inserted to the connection tracking table
1092 * if there is no existing entry with an identical tuple.
1094 * If there is one, @skb (and the assocated, unconfirmed conntrack) has
1095 * to be dropped. In case @skb is retransmitted, next conntrack lookup
1096 * will find the already-existing entry.
1098 * The major problem with such packet drop is the extra delay added by
1099 * the packet loss -- it will take some time for a retransmit to occur
1100 * (or the sender to time out when waiting for a reply).
1102 * This function attempts to handle the situation without packet drop.
1104 * If @skb has no NAT transformation or if the colliding entries are
1105 * exactly the same, only the to-be-confirmed conntrack entry is discarded
1106 * and @skb is associated with the conntrack entry already in the table.
1108 * Failing that, the new, unconfirmed conntrack is still added to the table
1109 * provided that the collision only occurs in the ORIGINAL direction.
1110 * The new entry will be added only in the non-clashing REPLY direction,
1111 * so packets in the ORIGINAL direction will continue to match the existing
1112 * entry. The new entry will also have a fixed timeout so it expires --
1113 * due to the collision, it will only see reply traffic.
1115 * Returns NF_DROP if the clash could not be resolved.
1117 static __cold noinline
int
1118 nf_ct_resolve_clash(struct sk_buff
*skb
, struct nf_conntrack_tuple_hash
*h
,
1121 /* This is the conntrack entry already in hashes that won race. */
1122 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
1123 const struct nf_conntrack_l4proto
*l4proto
;
1124 enum ip_conntrack_info ctinfo
;
1125 struct nf_conn
*loser_ct
;
1129 loser_ct
= nf_ct_get(skb
, &ctinfo
);
1130 net
= nf_ct_net(loser_ct
);
1132 l4proto
= nf_ct_l4proto_find(nf_ct_protonum(ct
));
1133 if (!l4proto
->allow_clash
)
1136 ret
= __nf_ct_resolve_clash(skb
, h
);
1137 if (ret
== NF_ACCEPT
)
1140 ret
= nf_ct_resolve_clash_harder(skb
, reply_hash
);
1141 if (ret
== NF_ACCEPT
)
1145 NF_CT_STAT_INC(net
, drop
);
1146 NF_CT_STAT_INC(net
, insert_failed
);
1150 /* Confirm a connection given skb; places it in hash table */
1152 __nf_conntrack_confirm(struct sk_buff
*skb
)
1154 unsigned int chainlen
= 0, sequence
, max_chainlen
;
1155 const struct nf_conntrack_zone
*zone
;
1156 unsigned int hash
, reply_hash
;
1157 struct nf_conntrack_tuple_hash
*h
;
1159 struct nf_conn_help
*help
;
1160 struct hlist_nulls_node
*n
;
1161 enum ip_conntrack_info ctinfo
;
1165 ct
= nf_ct_get(skb
, &ctinfo
);
1166 net
= nf_ct_net(ct
);
1168 /* ipt_REJECT uses nf_conntrack_attach to attach related
1169 ICMP/TCP RST packets in other direction. Actual packet
1170 which created connection will be IP_CT_NEW or for an
1171 expected connection, IP_CT_RELATED. */
1172 if (CTINFO2DIR(ctinfo
) != IP_CT_DIR_ORIGINAL
)
1175 zone
= nf_ct_zone(ct
);
1179 sequence
= read_seqcount_begin(&nf_conntrack_generation
);
1180 /* reuse the hash saved before */
1181 hash
= *(unsigned long *)&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnnode
.pprev
;
1182 hash
= scale_hash(hash
);
1183 reply_hash
= hash_conntrack(net
,
1184 &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
1185 nf_ct_zone_id(nf_ct_zone(ct
), IP_CT_DIR_REPLY
));
1186 } while (nf_conntrack_double_lock(net
, hash
, reply_hash
, sequence
));
1188 /* We're not in hash table, and we refuse to set up related
1189 * connections for unconfirmed conns. But packet copies and
1190 * REJECT will give spurious warnings here.
1193 /* Another skb with the same unconfirmed conntrack may
1194 * win the race. This may happen for bridge(br_flood)
1195 * or broadcast/multicast packets do skb_clone with
1196 * unconfirmed conntrack.
1198 if (unlikely(nf_ct_is_confirmed(ct
))) {
1200 nf_conntrack_double_unlock(hash
, reply_hash
);
1205 if (!nf_ct_ext_valid_pre(ct
->ext
)) {
1206 NF_CT_STAT_INC(net
, insert_failed
);
1210 pr_debug("Confirming conntrack %p\n", ct
);
1211 /* We have to check the DYING flag after unlink to prevent
1212 * a race against nf_ct_get_next_corpse() possibly called from
1213 * user context, else we insert an already 'dead' hash, blocking
1214 * further use of that particular connection -JM.
1216 ct
->status
|= IPS_CONFIRMED
;
1218 if (unlikely(nf_ct_is_dying(ct
))) {
1219 NF_CT_STAT_INC(net
, insert_failed
);
1223 max_chainlen
= MIN_CHAINLEN
+ prandom_u32_max(MAX_CHAINLEN
);
1224 /* See if there's one in the list already, including reverse:
1225 NAT could have grabbed it without realizing, since we're
1226 not in the hash. If there is, we lost race. */
1227 hlist_nulls_for_each_entry(h
, n
, &nf_conntrack_hash
[hash
], hnnode
) {
1228 if (nf_ct_key_equal(h
, &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
1231 if (chainlen
++ > max_chainlen
)
1236 hlist_nulls_for_each_entry(h
, n
, &nf_conntrack_hash
[reply_hash
], hnnode
) {
1237 if (nf_ct_key_equal(h
, &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
,
1240 if (chainlen
++ > max_chainlen
) {
1242 NF_CT_STAT_INC(net
, chaintoolong
);
1243 NF_CT_STAT_INC(net
, insert_failed
);
1249 /* Timer relative to confirmation time, not original
1250 setting time, otherwise we'd get timer wrap in
1251 weird delay cases. */
1252 ct
->timeout
+= nfct_time_stamp
;
1254 __nf_conntrack_insert_prepare(ct
);
1256 /* Since the lookup is lockless, hash insertion must be done after
1257 * starting the timer and setting the CONFIRMED bit. The RCU barriers
1258 * guarantee that no other CPU can find the conntrack before the above
1259 * stores are visible.
1261 __nf_conntrack_hash_insert(ct
, hash
, reply_hash
);
1262 nf_conntrack_double_unlock(hash
, reply_hash
);
1265 /* ext area is still valid (rcu read lock is held,
1266 * but will go out of scope soon, we need to remove
1267 * this conntrack again.
1269 if (!nf_ct_ext_valid_post(ct
->ext
)) {
1271 NF_CT_STAT_INC(net
, drop
);
1275 help
= nfct_help(ct
);
1276 if (help
&& help
->helper
)
1277 nf_conntrack_event_cache(IPCT_HELPER
, ct
);
1279 nf_conntrack_event_cache(master_ct(ct
) ?
1280 IPCT_RELATED
: IPCT_NEW
, ct
);
1284 ret
= nf_ct_resolve_clash(skb
, h
, reply_hash
);
1286 nf_conntrack_double_unlock(hash
, reply_hash
);
1290 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm
);
1292 /* Returns true if a connection correspondings to the tuple (required
1295 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple
*tuple
,
1296 const struct nf_conn
*ignored_conntrack
)
1298 struct net
*net
= nf_ct_net(ignored_conntrack
);
1299 const struct nf_conntrack_zone
*zone
;
1300 struct nf_conntrack_tuple_hash
*h
;
1301 struct hlist_nulls_head
*ct_hash
;
1302 unsigned int hash
, hsize
;
1303 struct hlist_nulls_node
*n
;
1306 zone
= nf_ct_zone(ignored_conntrack
);
1310 nf_conntrack_get_ht(&ct_hash
, &hsize
);
1311 hash
= __hash_conntrack(net
, tuple
, nf_ct_zone_id(zone
, IP_CT_DIR_REPLY
), hsize
);
1313 hlist_nulls_for_each_entry_rcu(h
, n
, &ct_hash
[hash
], hnnode
) {
1314 ct
= nf_ct_tuplehash_to_ctrack(h
);
1316 if (ct
== ignored_conntrack
)
1319 if (nf_ct_is_expired(ct
)) {
1320 nf_ct_gc_expired(ct
);
1324 if (nf_ct_key_equal(h
, tuple
, zone
, net
)) {
1325 /* Tuple is taken already, so caller will need to find
1326 * a new source port to use.
1329 * If the *original tuples* are identical, then both
1330 * conntracks refer to the same flow.
1331 * This is a rare situation, it can occur e.g. when
1332 * more than one UDP packet is sent from same socket
1333 * in different threads.
1335 * Let nf_ct_resolve_clash() deal with this later.
1337 if (nf_ct_tuple_equal(&ignored_conntrack
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
,
1338 &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
) &&
1339 nf_ct_zone_equal(ct
, zone
, IP_CT_DIR_ORIGINAL
))
1342 NF_CT_STAT_INC_ATOMIC(net
, found
);
1348 if (get_nulls_value(n
) != hash
) {
1349 NF_CT_STAT_INC_ATOMIC(net
, search_restart
);
1357 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken
);
1359 #define NF_CT_EVICTION_RANGE 8
1361 /* There's a small race here where we may free a just-assured
1362 connection. Too bad: we're in trouble anyway. */
1363 static unsigned int early_drop_list(struct net
*net
,
1364 struct hlist_nulls_head
*head
)
1366 struct nf_conntrack_tuple_hash
*h
;
1367 struct hlist_nulls_node
*n
;
1368 unsigned int drops
= 0;
1369 struct nf_conn
*tmp
;
1371 hlist_nulls_for_each_entry_rcu(h
, n
, head
, hnnode
) {
1372 tmp
= nf_ct_tuplehash_to_ctrack(h
);
1374 if (test_bit(IPS_OFFLOAD_BIT
, &tmp
->status
))
1377 if (nf_ct_is_expired(tmp
)) {
1378 nf_ct_gc_expired(tmp
);
1382 if (test_bit(IPS_ASSURED_BIT
, &tmp
->status
) ||
1383 !net_eq(nf_ct_net(tmp
), net
) ||
1384 nf_ct_is_dying(tmp
))
1387 if (!refcount_inc_not_zero(&tmp
->ct_general
.use
))
1390 /* kill only if still in same netns -- might have moved due to
1391 * SLAB_TYPESAFE_BY_RCU rules.
1393 * We steal the timer reference. If that fails timer has
1394 * already fired or someone else deleted it. Just drop ref
1395 * and move to next entry.
1397 if (net_eq(nf_ct_net(tmp
), net
) &&
1398 nf_ct_is_confirmed(tmp
) &&
1399 nf_ct_delete(tmp
, 0, 0))
1408 static noinline
int early_drop(struct net
*net
, unsigned int hash
)
1410 unsigned int i
, bucket
;
1412 for (i
= 0; i
< NF_CT_EVICTION_RANGE
; i
++) {
1413 struct hlist_nulls_head
*ct_hash
;
1414 unsigned int hsize
, drops
;
1417 nf_conntrack_get_ht(&ct_hash
, &hsize
);
1419 bucket
= reciprocal_scale(hash
, hsize
);
1421 bucket
= (bucket
+ 1) % hsize
;
1423 drops
= early_drop_list(net
, &ct_hash
[bucket
]);
1427 NF_CT_STAT_ADD_ATOMIC(net
, early_drop
, drops
);
1435 static bool gc_worker_skip_ct(const struct nf_conn
*ct
)
1437 return !nf_ct_is_confirmed(ct
) || nf_ct_is_dying(ct
);
1440 static bool gc_worker_can_early_drop(const struct nf_conn
*ct
)
1442 const struct nf_conntrack_l4proto
*l4proto
;
1444 if (!test_bit(IPS_ASSURED_BIT
, &ct
->status
))
1447 l4proto
= nf_ct_l4proto_find(nf_ct_protonum(ct
));
1448 if (l4proto
->can_early_drop
&& l4proto
->can_early_drop(ct
))
1454 static void gc_worker(struct work_struct
*work
)
1456 unsigned int i
, hashsz
, nf_conntrack_max95
= 0;
1457 u32 end_time
, start_time
= nfct_time_stamp
;
1458 struct conntrack_gc_work
*gc_work
;
1459 unsigned int expired_count
= 0;
1460 unsigned long next_run
;
1463 gc_work
= container_of(work
, struct conntrack_gc_work
, dwork
.work
);
1465 i
= gc_work
->next_bucket
;
1466 if (gc_work
->early_drop
)
1467 nf_conntrack_max95
= nf_conntrack_max
/ 100u * 95u;
1470 gc_work
->avg_timeout
= GC_SCAN_INTERVAL_INIT
;
1471 gc_work
->start_time
= start_time
;
1474 next_run
= gc_work
->avg_timeout
;
1476 end_time
= start_time
+ GC_SCAN_MAX_DURATION
;
1479 struct nf_conntrack_tuple_hash
*h
;
1480 struct hlist_nulls_head
*ct_hash
;
1481 struct hlist_nulls_node
*n
;
1482 struct nf_conn
*tmp
;
1486 nf_conntrack_get_ht(&ct_hash
, &hashsz
);
1492 hlist_nulls_for_each_entry_rcu(h
, n
, &ct_hash
[i
], hnnode
) {
1493 struct nf_conntrack_net
*cnet
;
1494 unsigned long expires
;
1497 tmp
= nf_ct_tuplehash_to_ctrack(h
);
1499 if (test_bit(IPS_OFFLOAD_BIT
, &tmp
->status
)) {
1500 nf_ct_offload_timeout(tmp
);
1504 if (expired_count
> GC_SCAN_EXPIRED_MAX
) {
1507 gc_work
->next_bucket
= i
;
1508 gc_work
->avg_timeout
= next_run
;
1510 delta_time
= nfct_time_stamp
- gc_work
->start_time
;
1512 /* re-sched immediately if total cycle time is exceeded */
1513 next_run
= delta_time
< (s32
)GC_SCAN_INTERVAL_MAX
;
1517 if (nf_ct_is_expired(tmp
)) {
1518 nf_ct_gc_expired(tmp
);
1523 expires
= clamp(nf_ct_expires(tmp
), GC_SCAN_INTERVAL_MIN
, GC_SCAN_INTERVAL_CLAMP
);
1524 next_run
+= expires
;
1527 if (nf_conntrack_max95
== 0 || gc_worker_skip_ct(tmp
))
1530 net
= nf_ct_net(tmp
);
1531 cnet
= nf_ct_pernet(net
);
1532 if (atomic_read(&cnet
->count
) < nf_conntrack_max95
)
1535 /* need to take reference to avoid possible races */
1536 if (!refcount_inc_not_zero(&tmp
->ct_general
.use
))
1539 if (gc_worker_skip_ct(tmp
)) {
1544 if (gc_worker_can_early_drop(tmp
)) {
1552 /* could check get_nulls_value() here and restart if ct
1553 * was moved to another chain. But given gc is best-effort
1554 * we will just continue with next hash slot.
1560 delta_time
= nfct_time_stamp
- end_time
;
1561 if (delta_time
> 0 && i
< hashsz
) {
1562 gc_work
->avg_timeout
= next_run
;
1563 gc_work
->next_bucket
= i
;
1567 } while (i
< hashsz
);
1569 gc_work
->next_bucket
= 0;
1571 next_run
= clamp(next_run
, GC_SCAN_INTERVAL_MIN
, GC_SCAN_INTERVAL_MAX
);
1573 delta_time
= max_t(s32
, nfct_time_stamp
- gc_work
->start_time
, 1);
1574 if (next_run
> (unsigned long)delta_time
)
1575 next_run
-= delta_time
;
1580 if (gc_work
->exiting
)
1584 gc_work
->early_drop
= false;
1586 queue_delayed_work(system_power_efficient_wq
, &gc_work
->dwork
, next_run
);
1589 static void conntrack_gc_work_init(struct conntrack_gc_work
*gc_work
)
1591 INIT_DELAYED_WORK(&gc_work
->dwork
, gc_worker
);
1592 gc_work
->exiting
= false;
1595 static struct nf_conn
*
1596 __nf_conntrack_alloc(struct net
*net
,
1597 const struct nf_conntrack_zone
*zone
,
1598 const struct nf_conntrack_tuple
*orig
,
1599 const struct nf_conntrack_tuple
*repl
,
1600 gfp_t gfp
, u32 hash
)
1602 struct nf_conntrack_net
*cnet
= nf_ct_pernet(net
);
1603 unsigned int ct_count
;
1606 /* We don't want any race condition at early drop stage */
1607 ct_count
= atomic_inc_return(&cnet
->count
);
1609 if (nf_conntrack_max
&& unlikely(ct_count
> nf_conntrack_max
)) {
1610 if (!early_drop(net
, hash
)) {
1611 if (!conntrack_gc_work
.early_drop
)
1612 conntrack_gc_work
.early_drop
= true;
1613 atomic_dec(&cnet
->count
);
1614 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1615 return ERR_PTR(-ENOMEM
);
1620 * Do not use kmem_cache_zalloc(), as this cache uses
1621 * SLAB_TYPESAFE_BY_RCU.
1623 ct
= kmem_cache_alloc(nf_conntrack_cachep
, gfp
);
1627 spin_lock_init(&ct
->lock
);
1628 ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
= *orig
;
1629 ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].hnnode
.pprev
= NULL
;
1630 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *repl
;
1631 /* save hash for reusing when confirming */
1632 *(unsigned long *)(&ct
->tuplehash
[IP_CT_DIR_REPLY
].hnnode
.pprev
) = hash
;
1634 WRITE_ONCE(ct
->timeout
, 0);
1635 write_pnet(&ct
->ct_net
, net
);
1636 memset_after(ct
, 0, __nfct_init_offset
);
1638 nf_ct_zone_add(ct
, zone
);
1640 /* Because we use RCU lookups, we set ct_general.use to zero before
1641 * this is inserted in any list.
1643 refcount_set(&ct
->ct_general
.use
, 0);
1646 atomic_dec(&cnet
->count
);
1647 return ERR_PTR(-ENOMEM
);
1650 struct nf_conn
*nf_conntrack_alloc(struct net
*net
,
1651 const struct nf_conntrack_zone
*zone
,
1652 const struct nf_conntrack_tuple
*orig
,
1653 const struct nf_conntrack_tuple
*repl
,
1656 return __nf_conntrack_alloc(net
, zone
, orig
, repl
, gfp
, 0);
1658 EXPORT_SYMBOL_GPL(nf_conntrack_alloc
);
1660 void nf_conntrack_free(struct nf_conn
*ct
)
1662 struct net
*net
= nf_ct_net(ct
);
1663 struct nf_conntrack_net
*cnet
;
1665 /* A freed object has refcnt == 0, that's
1666 * the golden rule for SLAB_TYPESAFE_BY_RCU
1668 WARN_ON(refcount_read(&ct
->ct_general
.use
) != 0);
1670 if (ct
->status
& IPS_SRC_NAT_DONE
) {
1671 const struct nf_nat_hook
*nat_hook
;
1674 nat_hook
= rcu_dereference(nf_nat_hook
);
1676 nat_hook
->remove_nat_bysrc(ct
);
1681 kmem_cache_free(nf_conntrack_cachep
, ct
);
1682 cnet
= nf_ct_pernet(net
);
1684 smp_mb__before_atomic();
1685 atomic_dec(&cnet
->count
);
1687 EXPORT_SYMBOL_GPL(nf_conntrack_free
);
1690 /* Allocate a new conntrack: we return -ENOMEM if classification
1691 failed due to stress. Otherwise it really is unclassifiable. */
1692 static noinline
struct nf_conntrack_tuple_hash
*
1693 init_conntrack(struct net
*net
, struct nf_conn
*tmpl
,
1694 const struct nf_conntrack_tuple
*tuple
,
1695 struct sk_buff
*skb
,
1696 unsigned int dataoff
, u32 hash
)
1699 struct nf_conn_help
*help
;
1700 struct nf_conntrack_tuple repl_tuple
;
1701 #ifdef CONFIG_NF_CONNTRACK_EVENTS
1702 struct nf_conntrack_ecache
*ecache
;
1704 struct nf_conntrack_expect
*exp
= NULL
;
1705 const struct nf_conntrack_zone
*zone
;
1706 struct nf_conn_timeout
*timeout_ext
;
1707 struct nf_conntrack_zone tmp
;
1708 struct nf_conntrack_net
*cnet
;
1710 if (!nf_ct_invert_tuple(&repl_tuple
, tuple
)) {
1711 pr_debug("Can't invert tuple.\n");
1715 zone
= nf_ct_zone_tmpl(tmpl
, skb
, &tmp
);
1716 ct
= __nf_conntrack_alloc(net
, zone
, tuple
, &repl_tuple
, GFP_ATOMIC
,
1719 return (struct nf_conntrack_tuple_hash
*)ct
;
1721 if (!nf_ct_add_synproxy(ct
, tmpl
)) {
1722 nf_conntrack_free(ct
);
1723 return ERR_PTR(-ENOMEM
);
1726 timeout_ext
= tmpl
? nf_ct_timeout_find(tmpl
) : NULL
;
1729 nf_ct_timeout_ext_add(ct
, rcu_dereference(timeout_ext
->timeout
),
1732 nf_ct_acct_ext_add(ct
, GFP_ATOMIC
);
1733 nf_ct_tstamp_ext_add(ct
, GFP_ATOMIC
);
1734 nf_ct_labels_ext_add(ct
);
1736 #ifdef CONFIG_NF_CONNTRACK_EVENTS
1737 ecache
= tmpl
? nf_ct_ecache_find(tmpl
) : NULL
;
1739 if ((ecache
|| net
->ct
.sysctl_events
) &&
1740 !nf_ct_ecache_ext_add(ct
, ecache
? ecache
->ctmask
: 0,
1741 ecache
? ecache
->expmask
: 0,
1743 nf_conntrack_free(ct
);
1744 return ERR_PTR(-ENOMEM
);
1748 cnet
= nf_ct_pernet(net
);
1749 if (cnet
->expect_count
) {
1750 spin_lock_bh(&nf_conntrack_expect_lock
);
1751 exp
= nf_ct_find_expectation(net
, zone
, tuple
);
1753 pr_debug("expectation arrives ct=%p exp=%p\n",
1755 /* Welcome, Mr. Bond. We've been expecting you... */
1756 __set_bit(IPS_EXPECTED_BIT
, &ct
->status
);
1757 /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1758 ct
->master
= exp
->master
;
1760 help
= nf_ct_helper_ext_add(ct
, GFP_ATOMIC
);
1762 rcu_assign_pointer(help
->helper
, exp
->helper
);
1765 #ifdef CONFIG_NF_CONNTRACK_MARK
1766 ct
->mark
= exp
->master
->mark
;
1768 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1769 ct
->secmark
= exp
->master
->secmark
;
1771 NF_CT_STAT_INC(net
, expect_new
);
1773 spin_unlock_bh(&nf_conntrack_expect_lock
);
1776 __nf_ct_try_assign_helper(ct
, tmpl
, GFP_ATOMIC
);
1778 /* Now it is going to be associated with an sk_buff, set refcount to 1. */
1779 refcount_set(&ct
->ct_general
.use
, 1);
1783 exp
->expectfn(ct
, exp
);
1784 nf_ct_expect_put(exp
);
1787 return &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
];
1790 /* On success, returns 0, sets skb->_nfct | ctinfo */
1792 resolve_normal_ct(struct nf_conn
*tmpl
,
1793 struct sk_buff
*skb
,
1794 unsigned int dataoff
,
1796 const struct nf_hook_state
*state
)
1798 const struct nf_conntrack_zone
*zone
;
1799 struct nf_conntrack_tuple tuple
;
1800 struct nf_conntrack_tuple_hash
*h
;
1801 enum ip_conntrack_info ctinfo
;
1802 struct nf_conntrack_zone tmp
;
1803 u32 hash
, zone_id
, rid
;
1806 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
),
1807 dataoff
, state
->pf
, protonum
, state
->net
,
1809 pr_debug("Can't get tuple\n");
1813 /* look for tuple match */
1814 zone
= nf_ct_zone_tmpl(tmpl
, skb
, &tmp
);
1816 zone_id
= nf_ct_zone_id(zone
, IP_CT_DIR_ORIGINAL
);
1817 hash
= hash_conntrack_raw(&tuple
, zone_id
, state
->net
);
1818 h
= __nf_conntrack_find_get(state
->net
, zone
, &tuple
, hash
);
1821 rid
= nf_ct_zone_id(zone
, IP_CT_DIR_REPLY
);
1822 if (zone_id
!= rid
) {
1823 u32 tmp
= hash_conntrack_raw(&tuple
, rid
, state
->net
);
1825 h
= __nf_conntrack_find_get(state
->net
, zone
, &tuple
, tmp
);
1830 h
= init_conntrack(state
->net
, tmpl
, &tuple
,
1831 skb
, dataoff
, hash
);
1837 ct
= nf_ct_tuplehash_to_ctrack(h
);
1839 /* It exists; we have (non-exclusive) reference. */
1840 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
) {
1841 ctinfo
= IP_CT_ESTABLISHED_REPLY
;
1843 /* Once we've had two way comms, always ESTABLISHED. */
1844 if (test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
1845 pr_debug("normal packet for %p\n", ct
);
1846 ctinfo
= IP_CT_ESTABLISHED
;
1847 } else if (test_bit(IPS_EXPECTED_BIT
, &ct
->status
)) {
1848 pr_debug("related packet for %p\n", ct
);
1849 ctinfo
= IP_CT_RELATED
;
1851 pr_debug("new packet for %p\n", ct
);
1855 nf_ct_set(skb
, ct
, ctinfo
);
1860 * icmp packets need special treatment to handle error messages that are
1861 * related to a connection.
1863 * Callers need to check if skb has a conntrack assigned when this
1864 * helper returns; in such case skb belongs to an already known connection.
1866 static unsigned int __cold
1867 nf_conntrack_handle_icmp(struct nf_conn
*tmpl
,
1868 struct sk_buff
*skb
,
1869 unsigned int dataoff
,
1871 const struct nf_hook_state
*state
)
1875 if (state
->pf
== NFPROTO_IPV4
&& protonum
== IPPROTO_ICMP
)
1876 ret
= nf_conntrack_icmpv4_error(tmpl
, skb
, dataoff
, state
);
1877 #if IS_ENABLED(CONFIG_IPV6)
1878 else if (state
->pf
== NFPROTO_IPV6
&& protonum
== IPPROTO_ICMPV6
)
1879 ret
= nf_conntrack_icmpv6_error(tmpl
, skb
, dataoff
, state
);
1885 NF_CT_STAT_INC_ATOMIC(state
->net
, error
);
1890 static int generic_packet(struct nf_conn
*ct
, struct sk_buff
*skb
,
1891 enum ip_conntrack_info ctinfo
)
1893 const unsigned int *timeout
= nf_ct_timeout_lookup(ct
);
1896 timeout
= &nf_generic_pernet(nf_ct_net(ct
))->timeout
;
1898 nf_ct_refresh_acct(ct
, ctinfo
, skb
, *timeout
);
1902 /* Returns verdict for packet, or -1 for invalid. */
1903 static int nf_conntrack_handle_packet(struct nf_conn
*ct
,
1904 struct sk_buff
*skb
,
1905 unsigned int dataoff
,
1906 enum ip_conntrack_info ctinfo
,
1907 const struct nf_hook_state
*state
)
1909 switch (nf_ct_protonum(ct
)) {
1911 return nf_conntrack_tcp_packet(ct
, skb
, dataoff
,
1914 return nf_conntrack_udp_packet(ct
, skb
, dataoff
,
1917 return nf_conntrack_icmp_packet(ct
, skb
, ctinfo
, state
);
1918 #if IS_ENABLED(CONFIG_IPV6)
1919 case IPPROTO_ICMPV6
:
1920 return nf_conntrack_icmpv6_packet(ct
, skb
, ctinfo
, state
);
1922 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
1923 case IPPROTO_UDPLITE
:
1924 return nf_conntrack_udplite_packet(ct
, skb
, dataoff
,
1927 #ifdef CONFIG_NF_CT_PROTO_SCTP
1929 return nf_conntrack_sctp_packet(ct
, skb
, dataoff
,
1932 #ifdef CONFIG_NF_CT_PROTO_DCCP
1934 return nf_conntrack_dccp_packet(ct
, skb
, dataoff
,
1937 #ifdef CONFIG_NF_CT_PROTO_GRE
1939 return nf_conntrack_gre_packet(ct
, skb
, dataoff
,
1944 return generic_packet(ct
, skb
, ctinfo
);
1948 nf_conntrack_in(struct sk_buff
*skb
, const struct nf_hook_state
*state
)
1950 enum ip_conntrack_info ctinfo
;
1951 struct nf_conn
*ct
, *tmpl
;
1955 tmpl
= nf_ct_get(skb
, &ctinfo
);
1956 if (tmpl
|| ctinfo
== IP_CT_UNTRACKED
) {
1957 /* Previously seen (loopback or untracked)? Ignore. */
1958 if ((tmpl
&& !nf_ct_is_template(tmpl
)) ||
1959 ctinfo
== IP_CT_UNTRACKED
)
1964 /* rcu_read_lock()ed by nf_hook_thresh */
1965 dataoff
= get_l4proto(skb
, skb_network_offset(skb
), state
->pf
, &protonum
);
1967 pr_debug("not prepared to track yet or error occurred\n");
1968 NF_CT_STAT_INC_ATOMIC(state
->net
, invalid
);
1973 if (protonum
== IPPROTO_ICMP
|| protonum
== IPPROTO_ICMPV6
) {
1974 ret
= nf_conntrack_handle_icmp(tmpl
, skb
, dataoff
,
1980 /* ICMP[v6] protocol trackers may assign one conntrack. */
1985 ret
= resolve_normal_ct(tmpl
, skb
, dataoff
,
1988 /* Too stressed to deal. */
1989 NF_CT_STAT_INC_ATOMIC(state
->net
, drop
);
1994 ct
= nf_ct_get(skb
, &ctinfo
);
1996 /* Not valid part of a connection */
1997 NF_CT_STAT_INC_ATOMIC(state
->net
, invalid
);
2002 ret
= nf_conntrack_handle_packet(ct
, skb
, dataoff
, ctinfo
, state
);
2004 /* Invalid: inverse of the return code tells
2005 * the netfilter core what to do */
2006 pr_debug("nf_conntrack_in: Can't track with proto module\n");
2009 /* Special case: TCP tracker reports an attempt to reopen a
2010 * closed/aborted connection. We have to go back and create a
2013 if (ret
== -NF_REPEAT
)
2016 NF_CT_STAT_INC_ATOMIC(state
->net
, invalid
);
2017 if (ret
== -NF_DROP
)
2018 NF_CT_STAT_INC_ATOMIC(state
->net
, drop
);
2024 if (ctinfo
== IP_CT_ESTABLISHED_REPLY
&&
2025 !test_and_set_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
))
2026 nf_conntrack_event_cache(IPCT_REPLY
, ct
);
2033 EXPORT_SYMBOL_GPL(nf_conntrack_in
);
2035 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
2036 implicitly racy: see __nf_conntrack_confirm */
2037 void nf_conntrack_alter_reply(struct nf_conn
*ct
,
2038 const struct nf_conntrack_tuple
*newreply
)
2040 struct nf_conn_help
*help
= nfct_help(ct
);
2042 /* Should be unconfirmed, so not in hash table yet */
2043 WARN_ON(nf_ct_is_confirmed(ct
));
2045 pr_debug("Altering reply tuple of %p to ", ct
);
2046 nf_ct_dump_tuple(newreply
);
2048 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
= *newreply
;
2049 if (ct
->master
|| (help
&& !hlist_empty(&help
->expectations
)))
2053 __nf_ct_try_assign_helper(ct
, NULL
, GFP_ATOMIC
);
2056 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply
);
2058 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
2059 void __nf_ct_refresh_acct(struct nf_conn
*ct
,
2060 enum ip_conntrack_info ctinfo
,
2061 const struct sk_buff
*skb
,
2065 /* Only update if this is not a fixed timeout */
2066 if (test_bit(IPS_FIXED_TIMEOUT_BIT
, &ct
->status
))
2069 /* If not in hash table, timer will not be active yet */
2070 if (nf_ct_is_confirmed(ct
))
2071 extra_jiffies
+= nfct_time_stamp
;
2073 if (READ_ONCE(ct
->timeout
) != extra_jiffies
)
2074 WRITE_ONCE(ct
->timeout
, extra_jiffies
);
2077 nf_ct_acct_update(ct
, CTINFO2DIR(ctinfo
), skb
->len
);
2079 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct
);
2081 bool nf_ct_kill_acct(struct nf_conn
*ct
,
2082 enum ip_conntrack_info ctinfo
,
2083 const struct sk_buff
*skb
)
2085 nf_ct_acct_update(ct
, CTINFO2DIR(ctinfo
), skb
->len
);
2087 return nf_ct_delete(ct
, 0, 0);
2089 EXPORT_SYMBOL_GPL(nf_ct_kill_acct
);
2091 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
2093 #include <linux/netfilter/nfnetlink.h>
2094 #include <linux/netfilter/nfnetlink_conntrack.h>
2095 #include <linux/mutex.h>
2097 /* Generic function for tcp/udp/sctp/dccp and alike. */
2098 int nf_ct_port_tuple_to_nlattr(struct sk_buff
*skb
,
2099 const struct nf_conntrack_tuple
*tuple
)
2101 if (nla_put_be16(skb
, CTA_PROTO_SRC_PORT
, tuple
->src
.u
.tcp
.port
) ||
2102 nla_put_be16(skb
, CTA_PROTO_DST_PORT
, tuple
->dst
.u
.tcp
.port
))
2103 goto nla_put_failure
;
2109 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr
);
2111 const struct nla_policy nf_ct_port_nla_policy
[CTA_PROTO_MAX
+1] = {
2112 [CTA_PROTO_SRC_PORT
] = { .type
= NLA_U16
},
2113 [CTA_PROTO_DST_PORT
] = { .type
= NLA_U16
},
2115 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy
);
2117 int nf_ct_port_nlattr_to_tuple(struct nlattr
*tb
[],
2118 struct nf_conntrack_tuple
*t
,
2121 if (flags
& CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT
)) {
2122 if (!tb
[CTA_PROTO_SRC_PORT
])
2125 t
->src
.u
.tcp
.port
= nla_get_be16(tb
[CTA_PROTO_SRC_PORT
]);
2128 if (flags
& CTA_FILTER_FLAG(CTA_PROTO_DST_PORT
)) {
2129 if (!tb
[CTA_PROTO_DST_PORT
])
2132 t
->dst
.u
.tcp
.port
= nla_get_be16(tb
[CTA_PROTO_DST_PORT
]);
2137 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple
);
2139 unsigned int nf_ct_port_nlattr_tuple_size(void)
2141 static unsigned int size __read_mostly
;
2144 size
= nla_policy_len(nf_ct_port_nla_policy
, CTA_PROTO_MAX
+ 1);
2148 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size
);
2151 /* Used by ipt_REJECT and ip6t_REJECT. */
2152 static void nf_conntrack_attach(struct sk_buff
*nskb
, const struct sk_buff
*skb
)
2155 enum ip_conntrack_info ctinfo
;
2157 /* This ICMP is in reverse direction to the packet which caused it */
2158 ct
= nf_ct_get(skb
, &ctinfo
);
2159 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
)
2160 ctinfo
= IP_CT_RELATED_REPLY
;
2162 ctinfo
= IP_CT_RELATED
;
2164 /* Attach to new skbuff, and increment count */
2165 nf_ct_set(nskb
, ct
, ctinfo
);
2166 nf_conntrack_get(skb_nfct(nskb
));
2169 static int __nf_conntrack_update(struct net
*net
, struct sk_buff
*skb
,
2171 enum ip_conntrack_info ctinfo
)
2173 const struct nf_nat_hook
*nat_hook
;
2174 struct nf_conntrack_tuple_hash
*h
;
2175 struct nf_conntrack_tuple tuple
;
2176 unsigned int status
;
2181 l3num
= nf_ct_l3num(ct
);
2183 dataoff
= get_l4proto(skb
, skb_network_offset(skb
), l3num
, &l4num
);
2187 if (!nf_ct_get_tuple(skb
, skb_network_offset(skb
), dataoff
, l3num
,
2188 l4num
, net
, &tuple
))
2191 if (ct
->status
& IPS_SRC_NAT
) {
2192 memcpy(tuple
.src
.u3
.all
,
2193 ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
.src
.u3
.all
,
2194 sizeof(tuple
.src
.u3
.all
));
2196 ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
.src
.u
.all
;
2199 if (ct
->status
& IPS_DST_NAT
) {
2200 memcpy(tuple
.dst
.u3
.all
,
2201 ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
.dst
.u3
.all
,
2202 sizeof(tuple
.dst
.u3
.all
));
2204 ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
.dst
.u
.all
;
2207 h
= nf_conntrack_find_get(net
, nf_ct_zone(ct
), &tuple
);
2211 /* Store status bits of the conntrack that is clashing to re-do NAT
2212 * mangling according to what it has been done already to this packet.
2214 status
= ct
->status
;
2217 ct
= nf_ct_tuplehash_to_ctrack(h
);
2218 nf_ct_set(skb
, ct
, ctinfo
);
2220 nat_hook
= rcu_dereference(nf_nat_hook
);
2224 if (status
& IPS_SRC_NAT
&&
2225 nat_hook
->manip_pkt(skb
, ct
, NF_NAT_MANIP_SRC
,
2226 IP_CT_DIR_ORIGINAL
) == NF_DROP
)
2229 if (status
& IPS_DST_NAT
&&
2230 nat_hook
->manip_pkt(skb
, ct
, NF_NAT_MANIP_DST
,
2231 IP_CT_DIR_ORIGINAL
) == NF_DROP
)
2237 /* This packet is coming from userspace via nf_queue, complete the packet
2238 * processing after the helper invocation in nf_confirm().
2240 static int nf_confirm_cthelper(struct sk_buff
*skb
, struct nf_conn
*ct
,
2241 enum ip_conntrack_info ctinfo
)
2243 const struct nf_conntrack_helper
*helper
;
2244 const struct nf_conn_help
*help
;
2247 help
= nfct_help(ct
);
2251 helper
= rcu_dereference(help
->helper
);
2252 if (!(helper
->flags
& NF_CT_HELPER_F_USERSPACE
))
2255 switch (nf_ct_l3num(ct
)) {
2257 protoff
= skb_network_offset(skb
) + ip_hdrlen(skb
);
2259 #if IS_ENABLED(CONFIG_IPV6)
2260 case NFPROTO_IPV6
: {
2264 pnum
= ipv6_hdr(skb
)->nexthdr
;
2265 protoff
= ipv6_skip_exthdr(skb
, sizeof(struct ipv6hdr
), &pnum
,
2267 if (protoff
< 0 || (frag_off
& htons(~0x7)) != 0)
2276 if (test_bit(IPS_SEQ_ADJUST_BIT
, &ct
->status
) &&
2277 !nf_is_loopback_packet(skb
)) {
2278 if (!nf_ct_seq_adjust(skb
, ct
, ctinfo
, protoff
)) {
2279 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct
), drop
);
2284 /* We've seen it coming out the other side: confirm it */
2285 return nf_conntrack_confirm(skb
) == NF_DROP
? - 1 : 0;
2288 static int nf_conntrack_update(struct net
*net
, struct sk_buff
*skb
)
2290 enum ip_conntrack_info ctinfo
;
2294 ct
= nf_ct_get(skb
, &ctinfo
);
2298 if (!nf_ct_is_confirmed(ct
)) {
2299 err
= __nf_conntrack_update(net
, skb
, ct
, ctinfo
);
2303 ct
= nf_ct_get(skb
, &ctinfo
);
2306 return nf_confirm_cthelper(skb
, ct
, ctinfo
);
2309 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple
*dst_tuple
,
2310 const struct sk_buff
*skb
)
2312 const struct nf_conntrack_tuple
*src_tuple
;
2313 const struct nf_conntrack_tuple_hash
*hash
;
2314 struct nf_conntrack_tuple srctuple
;
2315 enum ip_conntrack_info ctinfo
;
2318 ct
= nf_ct_get(skb
, &ctinfo
);
2320 src_tuple
= nf_ct_tuple(ct
, CTINFO2DIR(ctinfo
));
2321 memcpy(dst_tuple
, src_tuple
, sizeof(*dst_tuple
));
2325 if (!nf_ct_get_tuplepr(skb
, skb_network_offset(skb
),
2326 NFPROTO_IPV4
, dev_net(skb
->dev
),
2330 hash
= nf_conntrack_find_get(dev_net(skb
->dev
),
2336 ct
= nf_ct_tuplehash_to_ctrack(hash
);
2337 src_tuple
= nf_ct_tuple(ct
, !hash
->tuple
.dst
.dir
);
2338 memcpy(dst_tuple
, src_tuple
, sizeof(*dst_tuple
));
2344 /* Bring out ya dead! */
2345 static struct nf_conn
*
2346 get_next_corpse(int (*iter
)(struct nf_conn
*i
, void *data
),
2347 const struct nf_ct_iter_data
*iter_data
, unsigned int *bucket
)
2349 struct nf_conntrack_tuple_hash
*h
;
2351 struct hlist_nulls_node
*n
;
2354 for (; *bucket
< nf_conntrack_htable_size
; (*bucket
)++) {
2355 struct hlist_nulls_head
*hslot
= &nf_conntrack_hash
[*bucket
];
2357 if (hlist_nulls_empty(hslot
))
2360 lockp
= &nf_conntrack_locks
[*bucket
% CONNTRACK_LOCKS
];
2362 nf_conntrack_lock(lockp
);
2363 hlist_nulls_for_each_entry(h
, n
, hslot
, hnnode
) {
2364 if (NF_CT_DIRECTION(h
) != IP_CT_DIR_REPLY
)
2366 /* All nf_conn objects are added to hash table twice, one
2367 * for original direction tuple, once for the reply tuple.
2369 * Exception: In the IPS_NAT_CLASH case, only the reply
2370 * tuple is added (the original tuple already existed for
2371 * a different object).
2373 * We only need to call the iterator once for each
2374 * conntrack, so we just use the 'reply' direction
2375 * tuple while iterating.
2377 ct
= nf_ct_tuplehash_to_ctrack(h
);
2379 if (iter_data
->net
&&
2380 !net_eq(iter_data
->net
, nf_ct_net(ct
)))
2383 if (iter(ct
, iter_data
->data
))
2393 refcount_inc(&ct
->ct_general
.use
);
2399 static void nf_ct_iterate_cleanup(int (*iter
)(struct nf_conn
*i
, void *data
),
2400 const struct nf_ct_iter_data
*iter_data
)
2402 unsigned int bucket
= 0;
2407 mutex_lock(&nf_conntrack_mutex
);
2408 while ((ct
= get_next_corpse(iter
, iter_data
, &bucket
)) != NULL
) {
2409 /* Time to push up daises... */
2411 nf_ct_delete(ct
, iter_data
->portid
, iter_data
->report
);
2415 mutex_unlock(&nf_conntrack_mutex
);
2418 void nf_ct_iterate_cleanup_net(int (*iter
)(struct nf_conn
*i
, void *data
),
2419 const struct nf_ct_iter_data
*iter_data
)
2421 struct net
*net
= iter_data
->net
;
2422 struct nf_conntrack_net
*cnet
= nf_ct_pernet(net
);
2426 if (atomic_read(&cnet
->count
) == 0)
2429 nf_ct_iterate_cleanup(iter
, iter_data
);
2431 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net
);
2434 * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table
2435 * @iter: callback to invoke for each conntrack
2436 * @data: data to pass to @iter
2438 * Like nf_ct_iterate_cleanup, but first marks conntracks on the
2439 * unconfirmed list as dying (so they will not be inserted into
2442 * Can only be called in module exit path.
2445 nf_ct_iterate_destroy(int (*iter
)(struct nf_conn
*i
, void *data
), void *data
)
2447 struct nf_ct_iter_data iter_data
= {};
2450 down_read(&net_rwsem
);
2452 struct nf_conntrack_net
*cnet
= nf_ct_pernet(net
);
2454 if (atomic_read(&cnet
->count
) == 0)
2456 nf_queue_nf_hook_drop(net
);
2458 up_read(&net_rwsem
);
2460 /* Need to wait for netns cleanup worker to finish, if its
2461 * running -- it might have deleted a net namespace from
2462 * the global list, so hook drop above might not have
2463 * affected all namespaces.
2467 /* a skb w. unconfirmed conntrack could have been reinjected just
2468 * before we called nf_queue_nf_hook_drop().
2470 * This makes sure its inserted into conntrack table.
2474 nf_ct_ext_bump_genid();
2475 iter_data
.data
= data
;
2476 nf_ct_iterate_cleanup(iter
, &iter_data
);
2478 /* Another cpu might be in a rcu read section with
2479 * rcu protected pointer cleared in iter callback
2480 * or hidden via nf_ct_ext_bump_genid() above.
2482 * Wait until those are done.
2486 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy
);
2488 static int kill_all(struct nf_conn
*i
, void *data
)
2493 void nf_conntrack_cleanup_start(void)
2495 conntrack_gc_work
.exiting
= true;
2498 void nf_conntrack_cleanup_end(void)
2500 RCU_INIT_POINTER(nf_ct_hook
, NULL
);
2501 cancel_delayed_work_sync(&conntrack_gc_work
.dwork
);
2502 kvfree(nf_conntrack_hash
);
2504 nf_conntrack_proto_fini();
2505 nf_conntrack_helper_fini();
2506 nf_conntrack_expect_fini();
2508 kmem_cache_destroy(nf_conntrack_cachep
);
2512 * Mishearing the voices in his head, our hero wonders how he's
2513 * supposed to kill the mall.
2515 void nf_conntrack_cleanup_net(struct net
*net
)
2519 list_add(&net
->exit_list
, &single
);
2520 nf_conntrack_cleanup_net_list(&single
);
2523 void nf_conntrack_cleanup_net_list(struct list_head
*net_exit_list
)
2525 struct nf_ct_iter_data iter_data
= {};
2530 * This makes sure all current packets have passed through
2531 * netfilter framework. Roll on, two-stage module
2537 list_for_each_entry(net
, net_exit_list
, exit_list
) {
2538 struct nf_conntrack_net
*cnet
= nf_ct_pernet(net
);
2540 iter_data
.net
= net
;
2541 nf_ct_iterate_cleanup_net(kill_all
, &iter_data
);
2542 if (atomic_read(&cnet
->count
) != 0)
2547 goto i_see_dead_people
;
2550 list_for_each_entry(net
, net_exit_list
, exit_list
) {
2551 nf_conntrack_ecache_pernet_fini(net
);
2552 nf_conntrack_expect_pernet_fini(net
);
2553 free_percpu(net
->ct
.stat
);
2557 void *nf_ct_alloc_hashtable(unsigned int *sizep
, int nulls
)
2559 struct hlist_nulls_head
*hash
;
2560 unsigned int nr_slots
, i
;
2562 if (*sizep
> (UINT_MAX
/ sizeof(struct hlist_nulls_head
)))
2565 BUILD_BUG_ON(sizeof(struct hlist_nulls_head
) != sizeof(struct hlist_head
));
2566 nr_slots
= *sizep
= roundup(*sizep
, PAGE_SIZE
/ sizeof(struct hlist_nulls_head
));
2568 hash
= kvcalloc(nr_slots
, sizeof(struct hlist_nulls_head
), GFP_KERNEL
);
2571 for (i
= 0; i
< nr_slots
; i
++)
2572 INIT_HLIST_NULLS_HEAD(&hash
[i
], i
);
2576 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable
);
2578 int nf_conntrack_hash_resize(unsigned int hashsize
)
2581 unsigned int old_size
;
2582 struct hlist_nulls_head
*hash
, *old_hash
;
2583 struct nf_conntrack_tuple_hash
*h
;
2589 hash
= nf_ct_alloc_hashtable(&hashsize
, 1);
2593 mutex_lock(&nf_conntrack_mutex
);
2594 old_size
= nf_conntrack_htable_size
;
2595 if (old_size
== hashsize
) {
2596 mutex_unlock(&nf_conntrack_mutex
);
2602 nf_conntrack_all_lock();
2603 write_seqcount_begin(&nf_conntrack_generation
);
2605 /* Lookups in the old hash might happen in parallel, which means we
2606 * might get false negatives during connection lookup. New connections
2607 * created because of a false negative won't make it into the hash
2608 * though since that required taking the locks.
2611 for (i
= 0; i
< nf_conntrack_htable_size
; i
++) {
2612 while (!hlist_nulls_empty(&nf_conntrack_hash
[i
])) {
2613 unsigned int zone_id
;
2615 h
= hlist_nulls_entry(nf_conntrack_hash
[i
].first
,
2616 struct nf_conntrack_tuple_hash
, hnnode
);
2617 ct
= nf_ct_tuplehash_to_ctrack(h
);
2618 hlist_nulls_del_rcu(&h
->hnnode
);
2620 zone_id
= nf_ct_zone_id(nf_ct_zone(ct
), NF_CT_DIRECTION(h
));
2621 bucket
= __hash_conntrack(nf_ct_net(ct
),
2622 &h
->tuple
, zone_id
, hashsize
);
2623 hlist_nulls_add_head_rcu(&h
->hnnode
, &hash
[bucket
]);
2626 old_hash
= nf_conntrack_hash
;
2628 nf_conntrack_hash
= hash
;
2629 nf_conntrack_htable_size
= hashsize
;
2631 write_seqcount_end(&nf_conntrack_generation
);
2632 nf_conntrack_all_unlock();
2635 mutex_unlock(&nf_conntrack_mutex
);
2642 int nf_conntrack_set_hashsize(const char *val
, const struct kernel_param
*kp
)
2644 unsigned int hashsize
;
2647 if (current
->nsproxy
->net_ns
!= &init_net
)
2650 /* On boot, we can set this without any fancy locking. */
2651 if (!nf_conntrack_hash
)
2652 return param_set_uint(val
, kp
);
2654 rc
= kstrtouint(val
, 0, &hashsize
);
2658 return nf_conntrack_hash_resize(hashsize
);
2661 int nf_conntrack_init_start(void)
2663 unsigned long nr_pages
= totalram_pages();
2668 seqcount_spinlock_init(&nf_conntrack_generation
,
2669 &nf_conntrack_locks_all_lock
);
2671 for (i
= 0; i
< CONNTRACK_LOCKS
; i
++)
2672 spin_lock_init(&nf_conntrack_locks
[i
]);
2674 if (!nf_conntrack_htable_size
) {
2675 nf_conntrack_htable_size
2676 = (((nr_pages
<< PAGE_SHIFT
) / 16384)
2677 / sizeof(struct hlist_head
));
2678 if (BITS_PER_LONG
>= 64 &&
2679 nr_pages
> (4 * (1024 * 1024 * 1024 / PAGE_SIZE
)))
2680 nf_conntrack_htable_size
= 262144;
2681 else if (nr_pages
> (1024 * 1024 * 1024 / PAGE_SIZE
))
2682 nf_conntrack_htable_size
= 65536;
2684 if (nf_conntrack_htable_size
< 1024)
2685 nf_conntrack_htable_size
= 1024;
2686 /* Use a max. factor of one by default to keep the average
2687 * hash chain length at 2 entries. Each entry has to be added
2688 * twice (once for original direction, once for reply).
2689 * When a table size is given we use the old value of 8 to
2690 * avoid implicit reduction of the max entries setting.
2695 nf_conntrack_hash
= nf_ct_alloc_hashtable(&nf_conntrack_htable_size
, 1);
2696 if (!nf_conntrack_hash
)
2699 nf_conntrack_max
= max_factor
* nf_conntrack_htable_size
;
2701 nf_conntrack_cachep
= kmem_cache_create("nf_conntrack",
2702 sizeof(struct nf_conn
),
2704 SLAB_TYPESAFE_BY_RCU
| SLAB_HWCACHE_ALIGN
, NULL
);
2705 if (!nf_conntrack_cachep
)
2708 ret
= nf_conntrack_expect_init();
2712 ret
= nf_conntrack_helper_init();
2716 ret
= nf_conntrack_proto_init();
2720 conntrack_gc_work_init(&conntrack_gc_work
);
2721 queue_delayed_work(system_power_efficient_wq
, &conntrack_gc_work
.dwork
, HZ
);
2723 ret
= register_nf_conntrack_bpf();
2730 cancel_delayed_work_sync(&conntrack_gc_work
.dwork
);
2731 nf_conntrack_proto_fini();
2733 nf_conntrack_helper_fini();
2735 nf_conntrack_expect_fini();
2737 kmem_cache_destroy(nf_conntrack_cachep
);
2739 kvfree(nf_conntrack_hash
);
2743 static const struct nf_ct_hook nf_conntrack_hook
= {
2744 .update
= nf_conntrack_update
,
2745 .destroy
= nf_ct_destroy
,
2746 .get_tuple_skb
= nf_conntrack_get_tuple_skb
,
2747 .attach
= nf_conntrack_attach
,
2750 void nf_conntrack_init_end(void)
2752 RCU_INIT_POINTER(nf_ct_hook
, &nf_conntrack_hook
);
2756 * We need to use special "null" values, not used in hash table
2758 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0)
2760 int nf_conntrack_init_net(struct net
*net
)
2762 struct nf_conntrack_net
*cnet
= nf_ct_pernet(net
);
2765 BUILD_BUG_ON(IP_CT_UNTRACKED
== IP_CT_NUMBER
);
2766 BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS
);
2767 atomic_set(&cnet
->count
, 0);
2769 net
->ct
.stat
= alloc_percpu(struct ip_conntrack_stat
);
2773 ret
= nf_conntrack_expect_pernet_init(net
);
2777 nf_conntrack_acct_pernet_init(net
);
2778 nf_conntrack_tstamp_pernet_init(net
);
2779 nf_conntrack_ecache_pernet_init(net
);
2780 nf_conntrack_helper_pernet_init(net
);
2781 nf_conntrack_proto_pernet_init(net
);
2786 free_percpu(net
->ct
.stat
);