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
4 extension. */
5
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>
10 */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/types.h>
15 #include <linux/netfilter.h>
16 #include <linux/module.h>
17 #include <linux/sched.h>
18 #include <linux/skbuff.h>
19 #include <linux/proc_fs.h>
20 #include <linux/vmalloc.h>
21 #include <linux/stddef.h>
22 #include <linux/slab.h>
23 #include <linux/random.h>
24 #include <linux/jhash.h>
25 #include <linux/siphash.h>
26 #include <linux/err.h>
27 #include <linux/percpu.h>
28 #include <linux/moduleparam.h>
29 #include <linux/notifier.h>
30 #include <linux/kernel.h>
31 #include <linux/netdevice.h>
32 #include <linux/socket.h>
33 #include <linux/mm.h>
34 #include <linux/nsproxy.h>
35 #include <linux/rculist_nulls.h>
36
37 #include <net/netfilter/nf_conntrack.h>
38 #include <net/netfilter/nf_conntrack_l4proto.h>
39 #include <net/netfilter/nf_conntrack_expect.h>
40 #include <net/netfilter/nf_conntrack_helper.h>
41 #include <net/netfilter/nf_conntrack_seqadj.h>
42 #include <net/netfilter/nf_conntrack_core.h>
43 #include <net/netfilter/nf_conntrack_extend.h>
44 #include <net/netfilter/nf_conntrack_acct.h>
45 #include <net/netfilter/nf_conntrack_ecache.h>
46 #include <net/netfilter/nf_conntrack_zones.h>
47 #include <net/netfilter/nf_conntrack_timestamp.h>
48 #include <net/netfilter/nf_conntrack_timeout.h>
49 #include <net/netfilter/nf_conntrack_labels.h>
50 #include <net/netfilter/nf_conntrack_synproxy.h>
51 #include <net/netfilter/nf_nat.h>
52 #include <net/netfilter/nf_nat_helper.h>
53 #include <net/netns/hash.h>
54 #include <net/ip.h>
55
56 #include "nf_internals.h"
57
58 extern unsigned int nf_conntrack_net_id;
59
60 __cacheline_aligned_in_smp spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS];
61 EXPORT_SYMBOL_GPL(nf_conntrack_locks);
62
63 __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock);
64 EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock);
65
66 struct hlist_nulls_head *nf_conntrack_hash __read_mostly;
67 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
68
69 struct conntrack_gc_work {
70 struct delayed_work dwork;
71 u32 last_bucket;
72 bool exiting;
73 bool early_drop;
74 long next_gc_run;
75 };
76
77 static __read_mostly struct kmem_cache *nf_conntrack_cachep;
78 static DEFINE_SPINLOCK(nf_conntrack_locks_all_lock);
79 static __read_mostly bool nf_conntrack_locks_all;
80
81 /* every gc cycle scans at most 1/GC_MAX_BUCKETS_DIV part of table */
82 #define GC_MAX_BUCKETS_DIV 128u
83 /* upper bound of full table scan */
84 #define GC_MAX_SCAN_JIFFIES (16u * HZ)
85 /* desired ratio of entries found to be expired */
86 #define GC_EVICT_RATIO 50u
87
88 static struct conntrack_gc_work conntrack_gc_work;
89
90 extern unsigned int nf_conntrack_net_id;
91
nf_conntrack_lock(spinlock_t * lock)92 void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
93 {
94 /* 1) Acquire the lock */
95 spin_lock(lock);
96
97 /* 2) read nf_conntrack_locks_all, with ACQUIRE semantics
98 * It pairs with the smp_store_release() in nf_conntrack_all_unlock()
99 */
100 if (likely(smp_load_acquire(&nf_conntrack_locks_all) == false))
101 return;
102
103 /* fast path failed, unlock */
104 spin_unlock(lock);
105
106 /* Slow path 1) get global lock */
107 spin_lock(&nf_conntrack_locks_all_lock);
108
109 /* Slow path 2) get the lock we want */
110 spin_lock(lock);
111
112 /* Slow path 3) release the global lock */
113 spin_unlock(&nf_conntrack_locks_all_lock);
114 }
115 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
116
nf_conntrack_double_unlock(unsigned int h1,unsigned int h2)117 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2)
118 {
119 h1 %= CONNTRACK_LOCKS;
120 h2 %= CONNTRACK_LOCKS;
121 spin_unlock(&nf_conntrack_locks[h1]);
122 if (h1 != h2)
123 spin_unlock(&nf_conntrack_locks[h2]);
124 }
125
126 /* return true if we need to recompute hashes (in case hash table was resized) */
nf_conntrack_double_lock(struct net * net,unsigned int h1,unsigned int h2,unsigned int sequence)127 static bool nf_conntrack_double_lock(struct net *net, unsigned int h1,
128 unsigned int h2, unsigned int sequence)
129 {
130 h1 %= CONNTRACK_LOCKS;
131 h2 %= CONNTRACK_LOCKS;
132 if (h1 <= h2) {
133 nf_conntrack_lock(&nf_conntrack_locks[h1]);
134 if (h1 != h2)
135 spin_lock_nested(&nf_conntrack_locks[h2],
136 SINGLE_DEPTH_NESTING);
137 } else {
138 nf_conntrack_lock(&nf_conntrack_locks[h2]);
139 spin_lock_nested(&nf_conntrack_locks[h1],
140 SINGLE_DEPTH_NESTING);
141 }
142 if (read_seqcount_retry(&nf_conntrack_generation, sequence)) {
143 nf_conntrack_double_unlock(h1, h2);
144 return true;
145 }
146 return false;
147 }
148
nf_conntrack_all_lock(void)149 static void nf_conntrack_all_lock(void)
150 __acquires(&nf_conntrack_locks_all_lock)
151 {
152 int i;
153
154 spin_lock(&nf_conntrack_locks_all_lock);
155
156 nf_conntrack_locks_all = true;
157
158 for (i = 0; i < CONNTRACK_LOCKS; i++) {
159 spin_lock(&nf_conntrack_locks[i]);
160
161 /* This spin_unlock provides the "release" to ensure that
162 * nf_conntrack_locks_all==true is visible to everyone that
163 * acquired spin_lock(&nf_conntrack_locks[]).
164 */
165 spin_unlock(&nf_conntrack_locks[i]);
166 }
167 }
168
nf_conntrack_all_unlock(void)169 static void nf_conntrack_all_unlock(void)
170 __releases(&nf_conntrack_locks_all_lock)
171 {
172 /* All prior stores must be complete before we clear
173 * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
174 * might observe the false value but not the entire
175 * critical section.
176 * It pairs with the smp_load_acquire() in nf_conntrack_lock()
177 */
178 smp_store_release(&nf_conntrack_locks_all, false);
179 spin_unlock(&nf_conntrack_locks_all_lock);
180 }
181
182 unsigned int nf_conntrack_htable_size __read_mostly;
183 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
184
185 unsigned int nf_conntrack_max __read_mostly;
186 EXPORT_SYMBOL_GPL(nf_conntrack_max);
187 seqcount_spinlock_t nf_conntrack_generation __read_mostly;
188 static unsigned int nf_conntrack_hash_rnd __read_mostly;
189
hash_conntrack_raw(const struct nf_conntrack_tuple * tuple,const struct net * net)190 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
191 const struct net *net)
192 {
193 unsigned int n;
194 u32 seed;
195
196 get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
197
198 /* The direction must be ignored, so we hash everything up to the
199 * destination ports (which is a multiple of 4) and treat the last
200 * three bytes manually.
201 */
202 seed = nf_conntrack_hash_rnd ^ net_hash_mix(net);
203 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
204 return jhash2((u32 *)tuple, n, seed ^
205 (((__force __u16)tuple->dst.u.all << 16) |
206 tuple->dst.protonum));
207 }
208
scale_hash(u32 hash)209 static u32 scale_hash(u32 hash)
210 {
211 return reciprocal_scale(hash, nf_conntrack_htable_size);
212 }
213
__hash_conntrack(const struct net * net,const struct nf_conntrack_tuple * tuple,unsigned int size)214 static u32 __hash_conntrack(const struct net *net,
215 const struct nf_conntrack_tuple *tuple,
216 unsigned int size)
217 {
218 return reciprocal_scale(hash_conntrack_raw(tuple, net), size);
219 }
220
hash_conntrack(const struct net * net,const struct nf_conntrack_tuple * tuple)221 static u32 hash_conntrack(const struct net *net,
222 const struct nf_conntrack_tuple *tuple)
223 {
224 return scale_hash(hash_conntrack_raw(tuple, net));
225 }
226
nf_ct_get_tuple_ports(const struct sk_buff * skb,unsigned int dataoff,struct nf_conntrack_tuple * tuple)227 static bool nf_ct_get_tuple_ports(const struct sk_buff *skb,
228 unsigned int dataoff,
229 struct nf_conntrack_tuple *tuple)
230 { struct {
231 __be16 sport;
232 __be16 dport;
233 } _inet_hdr, *inet_hdr;
234
235 /* Actually only need first 4 bytes to get ports. */
236 inet_hdr = skb_header_pointer(skb, dataoff, sizeof(_inet_hdr), &_inet_hdr);
237 if (!inet_hdr)
238 return false;
239
240 tuple->src.u.udp.port = inet_hdr->sport;
241 tuple->dst.u.udp.port = inet_hdr->dport;
242 return true;
243 }
244
245 static bool
nf_ct_get_tuple(const struct sk_buff * skb,unsigned int nhoff,unsigned int dataoff,u_int16_t l3num,u_int8_t protonum,struct net * net,struct nf_conntrack_tuple * tuple)246 nf_ct_get_tuple(const struct sk_buff *skb,
247 unsigned int nhoff,
248 unsigned int dataoff,
249 u_int16_t l3num,
250 u_int8_t protonum,
251 struct net *net,
252 struct nf_conntrack_tuple *tuple)
253 {
254 unsigned int size;
255 const __be32 *ap;
256 __be32 _addrs[8];
257
258 memset(tuple, 0, sizeof(*tuple));
259
260 tuple->src.l3num = l3num;
261 switch (l3num) {
262 case NFPROTO_IPV4:
263 nhoff += offsetof(struct iphdr, saddr);
264 size = 2 * sizeof(__be32);
265 break;
266 case NFPROTO_IPV6:
267 nhoff += offsetof(struct ipv6hdr, saddr);
268 size = sizeof(_addrs);
269 break;
270 default:
271 return true;
272 }
273
274 ap = skb_header_pointer(skb, nhoff, size, _addrs);
275 if (!ap)
276 return false;
277
278 switch (l3num) {
279 case NFPROTO_IPV4:
280 tuple->src.u3.ip = ap[0];
281 tuple->dst.u3.ip = ap[1];
282 break;
283 case NFPROTO_IPV6:
284 memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
285 memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
286 break;
287 }
288
289 tuple->dst.protonum = protonum;
290 tuple->dst.dir = IP_CT_DIR_ORIGINAL;
291
292 switch (protonum) {
293 #if IS_ENABLED(CONFIG_IPV6)
294 case IPPROTO_ICMPV6:
295 return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple);
296 #endif
297 case IPPROTO_ICMP:
298 return icmp_pkt_to_tuple(skb, dataoff, net, tuple);
299 #ifdef CONFIG_NF_CT_PROTO_GRE
300 case IPPROTO_GRE:
301 return gre_pkt_to_tuple(skb, dataoff, net, tuple);
302 #endif
303 case IPPROTO_TCP:
304 case IPPROTO_UDP: /* fallthrough */
305 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
306 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
307 case IPPROTO_UDPLITE:
308 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
309 #endif
310 #ifdef CONFIG_NF_CT_PROTO_SCTP
311 case IPPROTO_SCTP:
312 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
313 #endif
314 #ifdef CONFIG_NF_CT_PROTO_DCCP
315 case IPPROTO_DCCP:
316 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
317 #endif
318 default:
319 break;
320 }
321
322 return true;
323 }
324
ipv4_get_l4proto(const struct sk_buff * skb,unsigned int nhoff,u_int8_t * protonum)325 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
326 u_int8_t *protonum)
327 {
328 int dataoff = -1;
329 const struct iphdr *iph;
330 struct iphdr _iph;
331
332 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
333 if (!iph)
334 return -1;
335
336 /* Conntrack defragments packets, we might still see fragments
337 * inside ICMP packets though.
338 */
339 if (iph->frag_off & htons(IP_OFFSET))
340 return -1;
341
342 dataoff = nhoff + (iph->ihl << 2);
343 *protonum = iph->protocol;
344
345 /* Check bogus IP headers */
346 if (dataoff > skb->len) {
347 pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
348 nhoff, iph->ihl << 2, skb->len);
349 return -1;
350 }
351 return dataoff;
352 }
353
354 #if IS_ENABLED(CONFIG_IPV6)
ipv6_get_l4proto(const struct sk_buff * skb,unsigned int nhoff,u8 * protonum)355 static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
356 u8 *protonum)
357 {
358 int protoff = -1;
359 unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
360 __be16 frag_off;
361 u8 nexthdr;
362
363 if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
364 &nexthdr, sizeof(nexthdr)) != 0) {
365 pr_debug("can't get nexthdr\n");
366 return -1;
367 }
368 protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
369 /*
370 * (protoff == skb->len) means the packet has not data, just
371 * IPv6 and possibly extensions headers, but it is tracked anyway
372 */
373 if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
374 pr_debug("can't find proto in pkt\n");
375 return -1;
376 }
377
378 *protonum = nexthdr;
379 return protoff;
380 }
381 #endif
382
get_l4proto(const struct sk_buff * skb,unsigned int nhoff,u8 pf,u8 * l4num)383 static int get_l4proto(const struct sk_buff *skb,
384 unsigned int nhoff, u8 pf, u8 *l4num)
385 {
386 switch (pf) {
387 case NFPROTO_IPV4:
388 return ipv4_get_l4proto(skb, nhoff, l4num);
389 #if IS_ENABLED(CONFIG_IPV6)
390 case NFPROTO_IPV6:
391 return ipv6_get_l4proto(skb, nhoff, l4num);
392 #endif
393 default:
394 *l4num = 0;
395 break;
396 }
397 return -1;
398 }
399
nf_ct_get_tuplepr(const struct sk_buff * skb,unsigned int nhoff,u_int16_t l3num,struct net * net,struct nf_conntrack_tuple * tuple)400 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
401 u_int16_t l3num,
402 struct net *net, struct nf_conntrack_tuple *tuple)
403 {
404 u8 protonum;
405 int protoff;
406
407 protoff = get_l4proto(skb, nhoff, l3num, &protonum);
408 if (protoff <= 0)
409 return false;
410
411 return nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple);
412 }
413 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
414
415 bool
nf_ct_invert_tuple(struct nf_conntrack_tuple * inverse,const struct nf_conntrack_tuple * orig)416 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
417 const struct nf_conntrack_tuple *orig)
418 {
419 memset(inverse, 0, sizeof(*inverse));
420
421 inverse->src.l3num = orig->src.l3num;
422
423 switch (orig->src.l3num) {
424 case NFPROTO_IPV4:
425 inverse->src.u3.ip = orig->dst.u3.ip;
426 inverse->dst.u3.ip = orig->src.u3.ip;
427 break;
428 case NFPROTO_IPV6:
429 inverse->src.u3.in6 = orig->dst.u3.in6;
430 inverse->dst.u3.in6 = orig->src.u3.in6;
431 break;
432 default:
433 break;
434 }
435
436 inverse->dst.dir = !orig->dst.dir;
437
438 inverse->dst.protonum = orig->dst.protonum;
439
440 switch (orig->dst.protonum) {
441 case IPPROTO_ICMP:
442 return nf_conntrack_invert_icmp_tuple(inverse, orig);
443 #if IS_ENABLED(CONFIG_IPV6)
444 case IPPROTO_ICMPV6:
445 return nf_conntrack_invert_icmpv6_tuple(inverse, orig);
446 #endif
447 }
448
449 inverse->src.u.all = orig->dst.u.all;
450 inverse->dst.u.all = orig->src.u.all;
451 return true;
452 }
453 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
454
455 /* Generate a almost-unique pseudo-id for a given conntrack.
456 *
457 * intentionally doesn't re-use any of the seeds used for hash
458 * table location, we assume id gets exposed to userspace.
459 *
460 * Following nf_conn items do not change throughout lifetime
461 * of the nf_conn:
462 *
463 * 1. nf_conn address
464 * 2. nf_conn->master address (normally NULL)
465 * 3. the associated net namespace
466 * 4. the original direction tuple
467 */
nf_ct_get_id(const struct nf_conn * ct)468 u32 nf_ct_get_id(const struct nf_conn *ct)
469 {
470 static __read_mostly siphash_key_t ct_id_seed;
471 unsigned long a, b, c, d;
472
473 net_get_random_once(&ct_id_seed, sizeof(ct_id_seed));
474
475 a = (unsigned long)ct;
476 b = (unsigned long)ct->master;
477 c = (unsigned long)nf_ct_net(ct);
478 d = (unsigned long)siphash(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
479 sizeof(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple),
480 &ct_id_seed);
481 #ifdef CONFIG_64BIT
482 return siphash_4u64((u64)a, (u64)b, (u64)c, (u64)d, &ct_id_seed);
483 #else
484 return siphash_4u32((u32)a, (u32)b, (u32)c, (u32)d, &ct_id_seed);
485 #endif
486 }
487 EXPORT_SYMBOL_GPL(nf_ct_get_id);
488
489 static void
clean_from_lists(struct nf_conn * ct)490 clean_from_lists(struct nf_conn *ct)
491 {
492 pr_debug("clean_from_lists(%p)\n", ct);
493 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
494 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
495
496 /* Destroy all pending expectations */
497 nf_ct_remove_expectations(ct);
498 }
499
500 /* must be called with local_bh_disable */
nf_ct_add_to_dying_list(struct nf_conn * ct)501 static void nf_ct_add_to_dying_list(struct nf_conn *ct)
502 {
503 struct ct_pcpu *pcpu;
504
505 /* add this conntrack to the (per cpu) dying list */
506 ct->cpu = smp_processor_id();
507 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
508
509 spin_lock(&pcpu->lock);
510 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
511 &pcpu->dying);
512 spin_unlock(&pcpu->lock);
513 }
514
515 /* must be called with local_bh_disable */
nf_ct_add_to_unconfirmed_list(struct nf_conn * ct)516 static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct)
517 {
518 struct ct_pcpu *pcpu;
519
520 /* add this conntrack to the (per cpu) unconfirmed list */
521 ct->cpu = smp_processor_id();
522 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
523
524 spin_lock(&pcpu->lock);
525 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
526 &pcpu->unconfirmed);
527 spin_unlock(&pcpu->lock);
528 }
529
530 /* must be called with local_bh_disable */
nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn * ct)531 static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct)
532 {
533 struct ct_pcpu *pcpu;
534
535 /* We overload first tuple to link into unconfirmed or dying list.*/
536 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
537
538 spin_lock(&pcpu->lock);
539 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
540 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
541 spin_unlock(&pcpu->lock);
542 }
543
544 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
545
546 /* Released via destroy_conntrack() */
nf_ct_tmpl_alloc(struct net * net,const struct nf_conntrack_zone * zone,gfp_t flags)547 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
548 const struct nf_conntrack_zone *zone,
549 gfp_t flags)
550 {
551 struct nf_conn *tmpl, *p;
552
553 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) {
554 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags);
555 if (!tmpl)
556 return NULL;
557
558 p = tmpl;
559 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
560 if (tmpl != p) {
561 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
562 tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p;
563 }
564 } else {
565 tmpl = kzalloc(sizeof(*tmpl), flags);
566 if (!tmpl)
567 return NULL;
568 }
569
570 tmpl->status = IPS_TEMPLATE;
571 write_pnet(&tmpl->ct_net, net);
572 nf_ct_zone_add(tmpl, zone);
573 atomic_set(&tmpl->ct_general.use, 0);
574
575 return tmpl;
576 }
577 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
578
nf_ct_tmpl_free(struct nf_conn * tmpl)579 void nf_ct_tmpl_free(struct nf_conn *tmpl)
580 {
581 nf_ct_ext_destroy(tmpl);
582
583 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
584 kfree((char *)tmpl - tmpl->proto.tmpl_padto);
585 else
586 kfree(tmpl);
587 }
588 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free);
589
destroy_gre_conntrack(struct nf_conn * ct)590 static void destroy_gre_conntrack(struct nf_conn *ct)
591 {
592 #ifdef CONFIG_NF_CT_PROTO_GRE
593 struct nf_conn *master = ct->master;
594
595 if (master)
596 nf_ct_gre_keymap_destroy(master);
597 #endif
598 }
599
600 static void
destroy_conntrack(struct nf_conntrack * nfct)601 destroy_conntrack(struct nf_conntrack *nfct)
602 {
603 struct nf_conn *ct = (struct nf_conn *)nfct;
604
605 pr_debug("destroy_conntrack(%p)\n", ct);
606 WARN_ON(atomic_read(&nfct->use) != 0);
607
608 if (unlikely(nf_ct_is_template(ct))) {
609 nf_ct_tmpl_free(ct);
610 return;
611 }
612
613 if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE))
614 destroy_gre_conntrack(ct);
615
616 local_bh_disable();
617 /* Expectations will have been removed in clean_from_lists,
618 * except TFTP can create an expectation on the first packet,
619 * before connection is in the list, so we need to clean here,
620 * too.
621 */
622 nf_ct_remove_expectations(ct);
623
624 nf_ct_del_from_dying_or_unconfirmed_list(ct);
625
626 local_bh_enable();
627
628 if (ct->master)
629 nf_ct_put(ct->master);
630
631 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
632 nf_conntrack_free(ct);
633 }
634
nf_ct_delete_from_lists(struct nf_conn * ct)635 static void nf_ct_delete_from_lists(struct nf_conn *ct)
636 {
637 struct net *net = nf_ct_net(ct);
638 unsigned int hash, reply_hash;
639 unsigned int sequence;
640
641 nf_ct_helper_destroy(ct);
642
643 local_bh_disable();
644 do {
645 sequence = read_seqcount_begin(&nf_conntrack_generation);
646 hash = hash_conntrack(net,
647 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
648 reply_hash = hash_conntrack(net,
649 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
650 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
651
652 clean_from_lists(ct);
653 nf_conntrack_double_unlock(hash, reply_hash);
654
655 nf_ct_add_to_dying_list(ct);
656
657 local_bh_enable();
658 }
659
nf_ct_delete(struct nf_conn * ct,u32 portid,int report)660 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
661 {
662 struct nf_conn_tstamp *tstamp;
663 struct net *net;
664
665 if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
666 return false;
667
668 tstamp = nf_conn_tstamp_find(ct);
669 if (tstamp && tstamp->stop == 0)
670 tstamp->stop = ktime_get_real_ns();
671
672 if (nf_conntrack_event_report(IPCT_DESTROY, ct,
673 portid, report) < 0) {
674 /* destroy event was not delivered. nf_ct_put will
675 * be done by event cache worker on redelivery.
676 */
677 nf_ct_delete_from_lists(ct);
678 nf_conntrack_ecache_work(nf_ct_net(ct), NFCT_ECACHE_DESTROY_FAIL);
679 return false;
680 }
681
682 net = nf_ct_net(ct);
683 if (nf_conntrack_ecache_dwork_pending(net))
684 nf_conntrack_ecache_work(net, NFCT_ECACHE_DESTROY_SENT);
685 nf_ct_delete_from_lists(ct);
686 nf_ct_put(ct);
687 return true;
688 }
689 EXPORT_SYMBOL_GPL(nf_ct_delete);
690
691 static inline bool
nf_ct_key_equal(struct nf_conntrack_tuple_hash * h,const struct nf_conntrack_tuple * tuple,const struct nf_conntrack_zone * zone,const struct net * net)692 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
693 const struct nf_conntrack_tuple *tuple,
694 const struct nf_conntrack_zone *zone,
695 const struct net *net)
696 {
697 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
698
699 /* A conntrack can be recreated with the equal tuple,
700 * so we need to check that the conntrack is confirmed
701 */
702 return nf_ct_tuple_equal(tuple, &h->tuple) &&
703 nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
704 nf_ct_is_confirmed(ct) &&
705 net_eq(net, nf_ct_net(ct));
706 }
707
708 static inline bool
nf_ct_match(const struct nf_conn * ct1,const struct nf_conn * ct2)709 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2)
710 {
711 return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
712 &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
713 nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple,
714 &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) &&
715 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) &&
716 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) &&
717 net_eq(nf_ct_net(ct1), nf_ct_net(ct2));
718 }
719
720 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
nf_ct_gc_expired(struct nf_conn * ct)721 static void nf_ct_gc_expired(struct nf_conn *ct)
722 {
723 if (!atomic_inc_not_zero(&ct->ct_general.use))
724 return;
725
726 if (nf_ct_should_gc(ct))
727 nf_ct_kill(ct);
728
729 nf_ct_put(ct);
730 }
731
732 /*
733 * Warning :
734 * - Caller must take a reference on returned object
735 * and recheck nf_ct_tuple_equal(tuple, &h->tuple)
736 */
737 static struct nf_conntrack_tuple_hash *
____nf_conntrack_find(struct net * net,const struct nf_conntrack_zone * zone,const struct nf_conntrack_tuple * tuple,u32 hash)738 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
739 const struct nf_conntrack_tuple *tuple, u32 hash)
740 {
741 struct nf_conntrack_tuple_hash *h;
742 struct hlist_nulls_head *ct_hash;
743 struct hlist_nulls_node *n;
744 unsigned int bucket, hsize;
745
746 begin:
747 nf_conntrack_get_ht(&ct_hash, &hsize);
748 bucket = reciprocal_scale(hash, hsize);
749
750 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
751 struct nf_conn *ct;
752
753 ct = nf_ct_tuplehash_to_ctrack(h);
754 if (nf_ct_is_expired(ct)) {
755 nf_ct_gc_expired(ct);
756 continue;
757 }
758
759 if (nf_ct_key_equal(h, tuple, zone, net))
760 return h;
761 }
762 /*
763 * if the nulls value we got at the end of this lookup is
764 * not the expected one, we must restart lookup.
765 * We probably met an item that was moved to another chain.
766 */
767 if (get_nulls_value(n) != bucket) {
768 NF_CT_STAT_INC_ATOMIC(net, search_restart);
769 goto begin;
770 }
771
772 return NULL;
773 }
774
775 /* Find a connection corresponding to a tuple. */
776 static struct nf_conntrack_tuple_hash *
__nf_conntrack_find_get(struct net * net,const struct nf_conntrack_zone * zone,const struct nf_conntrack_tuple * tuple,u32 hash)777 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
778 const struct nf_conntrack_tuple *tuple, u32 hash)
779 {
780 struct nf_conntrack_tuple_hash *h;
781 struct nf_conn *ct;
782
783 rcu_read_lock();
784
785 h = ____nf_conntrack_find(net, zone, tuple, hash);
786 if (h) {
787 /* We have a candidate that matches the tuple we're interested
788 * in, try to obtain a reference and re-check tuple
789 */
790 ct = nf_ct_tuplehash_to_ctrack(h);
791 if (likely(atomic_inc_not_zero(&ct->ct_general.use))) {
792 if (likely(nf_ct_key_equal(h, tuple, zone, net)))
793 goto found;
794
795 /* TYPESAFE_BY_RCU recycled the candidate */
796 nf_ct_put(ct);
797 }
798
799 h = NULL;
800 }
801 found:
802 rcu_read_unlock();
803
804 return h;
805 }
806
807 struct nf_conntrack_tuple_hash *
nf_conntrack_find_get(struct net * net,const struct nf_conntrack_zone * zone,const struct nf_conntrack_tuple * tuple)808 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
809 const struct nf_conntrack_tuple *tuple)
810 {
811 return __nf_conntrack_find_get(net, zone, tuple,
812 hash_conntrack_raw(tuple, net));
813 }
814 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
815
__nf_conntrack_hash_insert(struct nf_conn * ct,unsigned int hash,unsigned int reply_hash)816 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
817 unsigned int hash,
818 unsigned int reply_hash)
819 {
820 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
821 &nf_conntrack_hash[hash]);
822 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
823 &nf_conntrack_hash[reply_hash]);
824 }
825
826 int
nf_conntrack_hash_check_insert(struct nf_conn * ct)827 nf_conntrack_hash_check_insert(struct nf_conn *ct)
828 {
829 const struct nf_conntrack_zone *zone;
830 struct net *net = nf_ct_net(ct);
831 unsigned int hash, reply_hash;
832 struct nf_conntrack_tuple_hash *h;
833 struct hlist_nulls_node *n;
834 unsigned int sequence;
835
836 zone = nf_ct_zone(ct);
837
838 local_bh_disable();
839 do {
840 sequence = read_seqcount_begin(&nf_conntrack_generation);
841 hash = hash_conntrack(net,
842 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
843 reply_hash = hash_conntrack(net,
844 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
845 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
846
847 /* See if there's one in the list already, including reverse */
848 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
849 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
850 zone, net))
851 goto out;
852
853 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
854 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
855 zone, net))
856 goto out;
857
858 smp_wmb();
859 /* The caller holds a reference to this object */
860 atomic_set(&ct->ct_general.use, 2);
861 __nf_conntrack_hash_insert(ct, hash, reply_hash);
862 nf_conntrack_double_unlock(hash, reply_hash);
863 NF_CT_STAT_INC(net, insert);
864 local_bh_enable();
865 return 0;
866
867 out:
868 nf_conntrack_double_unlock(hash, reply_hash);
869 local_bh_enable();
870 return -EEXIST;
871 }
872 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
873
nf_ct_acct_add(struct nf_conn * ct,u32 dir,unsigned int packets,unsigned int bytes)874 void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets,
875 unsigned int bytes)
876 {
877 struct nf_conn_acct *acct;
878
879 acct = nf_conn_acct_find(ct);
880 if (acct) {
881 struct nf_conn_counter *counter = acct->counter;
882
883 atomic64_add(packets, &counter[dir].packets);
884 atomic64_add(bytes, &counter[dir].bytes);
885 }
886 }
887 EXPORT_SYMBOL_GPL(nf_ct_acct_add);
888
nf_ct_acct_merge(struct nf_conn * ct,enum ip_conntrack_info ctinfo,const struct nf_conn * loser_ct)889 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
890 const struct nf_conn *loser_ct)
891 {
892 struct nf_conn_acct *acct;
893
894 acct = nf_conn_acct_find(loser_ct);
895 if (acct) {
896 struct nf_conn_counter *counter = acct->counter;
897 unsigned int bytes;
898
899 /* u32 should be fine since we must have seen one packet. */
900 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
901 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), bytes);
902 }
903 }
904
__nf_conntrack_insert_prepare(struct nf_conn * ct)905 static void __nf_conntrack_insert_prepare(struct nf_conn *ct)
906 {
907 struct nf_conn_tstamp *tstamp;
908
909 atomic_inc(&ct->ct_general.use);
910 ct->status |= IPS_CONFIRMED;
911
912 /* set conntrack timestamp, if enabled. */
913 tstamp = nf_conn_tstamp_find(ct);
914 if (tstamp)
915 tstamp->start = ktime_get_real_ns();
916 }
917
918 /* caller must hold locks to prevent concurrent changes */
__nf_ct_resolve_clash(struct sk_buff * skb,struct nf_conntrack_tuple_hash * h)919 static int __nf_ct_resolve_clash(struct sk_buff *skb,
920 struct nf_conntrack_tuple_hash *h)
921 {
922 /* This is the conntrack entry already in hashes that won race. */
923 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
924 enum ip_conntrack_info ctinfo;
925 struct nf_conn *loser_ct;
926
927 loser_ct = nf_ct_get(skb, &ctinfo);
928
929 if (nf_ct_is_dying(ct))
930 return NF_DROP;
931
932 if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
933 nf_ct_match(ct, loser_ct)) {
934 struct net *net = nf_ct_net(ct);
935
936 nf_conntrack_get(&ct->ct_general);
937
938 nf_ct_acct_merge(ct, ctinfo, loser_ct);
939 nf_ct_add_to_dying_list(loser_ct);
940 nf_conntrack_put(&loser_ct->ct_general);
941 nf_ct_set(skb, ct, ctinfo);
942
943 NF_CT_STAT_INC(net, clash_resolve);
944 return NF_ACCEPT;
945 }
946
947 return NF_DROP;
948 }
949
950 /**
951 * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry
952 *
953 * @skb: skb that causes the collision
954 * @repl_idx: hash slot for reply direction
955 *
956 * Called when origin or reply direction had a clash.
957 * The skb can be handled without packet drop provided the reply direction
958 * is unique or there the existing entry has the identical tuple in both
959 * directions.
960 *
961 * Caller must hold conntrack table locks to prevent concurrent updates.
962 *
963 * Returns NF_DROP if the clash could not be handled.
964 */
nf_ct_resolve_clash_harder(struct sk_buff * skb,u32 repl_idx)965 static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx)
966 {
967 struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb);
968 const struct nf_conntrack_zone *zone;
969 struct nf_conntrack_tuple_hash *h;
970 struct hlist_nulls_node *n;
971 struct net *net;
972
973 zone = nf_ct_zone(loser_ct);
974 net = nf_ct_net(loser_ct);
975
976 /* Reply direction must never result in a clash, unless both origin
977 * and reply tuples are identical.
978 */
979 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) {
980 if (nf_ct_key_equal(h,
981 &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple,
982 zone, net))
983 return __nf_ct_resolve_clash(skb, h);
984 }
985
986 /* We want the clashing entry to go away real soon: 1 second timeout. */
987 loser_ct->timeout = nfct_time_stamp + HZ;
988
989 /* IPS_NAT_CLASH removes the entry automatically on the first
990 * reply. Also prevents UDP tracker from moving the entry to
991 * ASSURED state, i.e. the entry can always be evicted under
992 * pressure.
993 */
994 loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH;
995
996 __nf_conntrack_insert_prepare(loser_ct);
997
998 /* fake add for ORIGINAL dir: we want lookups to only find the entry
999 * already in the table. This also hides the clashing entry from
1000 * ctnetlink iteration, i.e. conntrack -L won't show them.
1001 */
1002 hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
1003
1004 hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
1005 &nf_conntrack_hash[repl_idx]);
1006
1007 NF_CT_STAT_INC(net, clash_resolve);
1008 return NF_ACCEPT;
1009 }
1010
1011 /**
1012 * nf_ct_resolve_clash - attempt to handle clash without packet drop
1013 *
1014 * @skb: skb that causes the clash
1015 * @h: tuplehash of the clashing entry already in table
1016 * @reply_hash: hash slot for reply direction
1017 *
1018 * A conntrack entry can be inserted to the connection tracking table
1019 * if there is no existing entry with an identical tuple.
1020 *
1021 * If there is one, @skb (and the assocated, unconfirmed conntrack) has
1022 * to be dropped. In case @skb is retransmitted, next conntrack lookup
1023 * will find the already-existing entry.
1024 *
1025 * The major problem with such packet drop is the extra delay added by
1026 * the packet loss -- it will take some time for a retransmit to occur
1027 * (or the sender to time out when waiting for a reply).
1028 *
1029 * This function attempts to handle the situation without packet drop.
1030 *
1031 * If @skb has no NAT transformation or if the colliding entries are
1032 * exactly the same, only the to-be-confirmed conntrack entry is discarded
1033 * and @skb is associated with the conntrack entry already in the table.
1034 *
1035 * Failing that, the new, unconfirmed conntrack is still added to the table
1036 * provided that the collision only occurs in the ORIGINAL direction.
1037 * The new entry will be added only in the non-clashing REPLY direction,
1038 * so packets in the ORIGINAL direction will continue to match the existing
1039 * entry. The new entry will also have a fixed timeout so it expires --
1040 * due to the collision, it will only see reply traffic.
1041 *
1042 * Returns NF_DROP if the clash could not be resolved.
1043 */
1044 static __cold noinline int
nf_ct_resolve_clash(struct sk_buff * skb,struct nf_conntrack_tuple_hash * h,u32 reply_hash)1045 nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h,
1046 u32 reply_hash)
1047 {
1048 /* This is the conntrack entry already in hashes that won race. */
1049 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
1050 const struct nf_conntrack_l4proto *l4proto;
1051 enum ip_conntrack_info ctinfo;
1052 struct nf_conn *loser_ct;
1053 struct net *net;
1054 int ret;
1055
1056 loser_ct = nf_ct_get(skb, &ctinfo);
1057 net = nf_ct_net(loser_ct);
1058
1059 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1060 if (!l4proto->allow_clash)
1061 goto drop;
1062
1063 ret = __nf_ct_resolve_clash(skb, h);
1064 if (ret == NF_ACCEPT)
1065 return ret;
1066
1067 ret = nf_ct_resolve_clash_harder(skb, reply_hash);
1068 if (ret == NF_ACCEPT)
1069 return ret;
1070
1071 drop:
1072 nf_ct_add_to_dying_list(loser_ct);
1073 NF_CT_STAT_INC(net, drop);
1074 NF_CT_STAT_INC(net, insert_failed);
1075 return NF_DROP;
1076 }
1077
1078 /* Confirm a connection given skb; places it in hash table */
1079 int
__nf_conntrack_confirm(struct sk_buff * skb)1080 __nf_conntrack_confirm(struct sk_buff *skb)
1081 {
1082 const struct nf_conntrack_zone *zone;
1083 unsigned int hash, reply_hash;
1084 struct nf_conntrack_tuple_hash *h;
1085 struct nf_conn *ct;
1086 struct nf_conn_help *help;
1087 struct hlist_nulls_node *n;
1088 enum ip_conntrack_info ctinfo;
1089 struct net *net;
1090 unsigned int sequence;
1091 int ret = NF_DROP;
1092
1093 ct = nf_ct_get(skb, &ctinfo);
1094 net = nf_ct_net(ct);
1095
1096 /* ipt_REJECT uses nf_conntrack_attach to attach related
1097 ICMP/TCP RST packets in other direction. Actual packet
1098 which created connection will be IP_CT_NEW or for an
1099 expected connection, IP_CT_RELATED. */
1100 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
1101 return NF_ACCEPT;
1102
1103 zone = nf_ct_zone(ct);
1104 local_bh_disable();
1105
1106 do {
1107 sequence = read_seqcount_begin(&nf_conntrack_generation);
1108 /* reuse the hash saved before */
1109 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
1110 hash = scale_hash(hash);
1111 reply_hash = hash_conntrack(net,
1112 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
1113
1114 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
1115
1116 /* We're not in hash table, and we refuse to set up related
1117 * connections for unconfirmed conns. But packet copies and
1118 * REJECT will give spurious warnings here.
1119 */
1120
1121 /* Another skb with the same unconfirmed conntrack may
1122 * win the race. This may happen for bridge(br_flood)
1123 * or broadcast/multicast packets do skb_clone with
1124 * unconfirmed conntrack.
1125 */
1126 if (unlikely(nf_ct_is_confirmed(ct))) {
1127 WARN_ON_ONCE(1);
1128 nf_conntrack_double_unlock(hash, reply_hash);
1129 local_bh_enable();
1130 return NF_DROP;
1131 }
1132
1133 pr_debug("Confirming conntrack %p\n", ct);
1134 /* We have to check the DYING flag after unlink to prevent
1135 * a race against nf_ct_get_next_corpse() possibly called from
1136 * user context, else we insert an already 'dead' hash, blocking
1137 * further use of that particular connection -JM.
1138 */
1139 nf_ct_del_from_dying_or_unconfirmed_list(ct);
1140
1141 if (unlikely(nf_ct_is_dying(ct))) {
1142 nf_ct_add_to_dying_list(ct);
1143 NF_CT_STAT_INC(net, insert_failed);
1144 goto dying;
1145 }
1146
1147 /* See if there's one in the list already, including reverse:
1148 NAT could have grabbed it without realizing, since we're
1149 not in the hash. If there is, we lost race. */
1150 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
1151 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1152 zone, net))
1153 goto out;
1154
1155 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
1156 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1157 zone, net))
1158 goto out;
1159
1160 /* Timer relative to confirmation time, not original
1161 setting time, otherwise we'd get timer wrap in
1162 weird delay cases. */
1163 ct->timeout += nfct_time_stamp;
1164
1165 __nf_conntrack_insert_prepare(ct);
1166
1167 /* Since the lookup is lockless, hash insertion must be done after
1168 * starting the timer and setting the CONFIRMED bit. The RCU barriers
1169 * guarantee that no other CPU can find the conntrack before the above
1170 * stores are visible.
1171 */
1172 __nf_conntrack_hash_insert(ct, hash, reply_hash);
1173 nf_conntrack_double_unlock(hash, reply_hash);
1174 local_bh_enable();
1175
1176 help = nfct_help(ct);
1177 if (help && help->helper)
1178 nf_conntrack_event_cache(IPCT_HELPER, ct);
1179
1180 nf_conntrack_event_cache(master_ct(ct) ?
1181 IPCT_RELATED : IPCT_NEW, ct);
1182 return NF_ACCEPT;
1183
1184 out:
1185 ret = nf_ct_resolve_clash(skb, h, reply_hash);
1186 dying:
1187 nf_conntrack_double_unlock(hash, reply_hash);
1188 local_bh_enable();
1189 return ret;
1190 }
1191 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
1192
1193 /* Returns true if a connection correspondings to the tuple (required
1194 for NAT). */
1195 int
nf_conntrack_tuple_taken(const struct nf_conntrack_tuple * tuple,const struct nf_conn * ignored_conntrack)1196 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
1197 const struct nf_conn *ignored_conntrack)
1198 {
1199 struct net *net = nf_ct_net(ignored_conntrack);
1200 const struct nf_conntrack_zone *zone;
1201 struct nf_conntrack_tuple_hash *h;
1202 struct hlist_nulls_head *ct_hash;
1203 unsigned int hash, hsize;
1204 struct hlist_nulls_node *n;
1205 struct nf_conn *ct;
1206
1207 zone = nf_ct_zone(ignored_conntrack);
1208
1209 rcu_read_lock();
1210 begin:
1211 nf_conntrack_get_ht(&ct_hash, &hsize);
1212 hash = __hash_conntrack(net, tuple, hsize);
1213
1214 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
1215 ct = nf_ct_tuplehash_to_ctrack(h);
1216
1217 if (ct == ignored_conntrack)
1218 continue;
1219
1220 if (nf_ct_is_expired(ct)) {
1221 nf_ct_gc_expired(ct);
1222 continue;
1223 }
1224
1225 if (nf_ct_key_equal(h, tuple, zone, net)) {
1226 /* Tuple is taken already, so caller will need to find
1227 * a new source port to use.
1228 *
1229 * Only exception:
1230 * If the *original tuples* are identical, then both
1231 * conntracks refer to the same flow.
1232 * This is a rare situation, it can occur e.g. when
1233 * more than one UDP packet is sent from same socket
1234 * in different threads.
1235 *
1236 * Let nf_ct_resolve_clash() deal with this later.
1237 */
1238 if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1239 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
1240 nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL))
1241 continue;
1242
1243 NF_CT_STAT_INC_ATOMIC(net, found);
1244 rcu_read_unlock();
1245 return 1;
1246 }
1247 }
1248
1249 if (get_nulls_value(n) != hash) {
1250 NF_CT_STAT_INC_ATOMIC(net, search_restart);
1251 goto begin;
1252 }
1253
1254 rcu_read_unlock();
1255
1256 return 0;
1257 }
1258 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
1259
1260 #define NF_CT_EVICTION_RANGE 8
1261
1262 /* There's a small race here where we may free a just-assured
1263 connection. Too bad: we're in trouble anyway. */
early_drop_list(struct net * net,struct hlist_nulls_head * head)1264 static unsigned int early_drop_list(struct net *net,
1265 struct hlist_nulls_head *head)
1266 {
1267 struct nf_conntrack_tuple_hash *h;
1268 struct hlist_nulls_node *n;
1269 unsigned int drops = 0;
1270 struct nf_conn *tmp;
1271
1272 hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
1273 tmp = nf_ct_tuplehash_to_ctrack(h);
1274
1275 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status))
1276 continue;
1277
1278 if (nf_ct_is_expired(tmp)) {
1279 nf_ct_gc_expired(tmp);
1280 continue;
1281 }
1282
1283 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
1284 !net_eq(nf_ct_net(tmp), net) ||
1285 nf_ct_is_dying(tmp))
1286 continue;
1287
1288 if (!atomic_inc_not_zero(&tmp->ct_general.use))
1289 continue;
1290
1291 /* kill only if still in same netns -- might have moved due to
1292 * SLAB_TYPESAFE_BY_RCU rules.
1293 *
1294 * We steal the timer reference. If that fails timer has
1295 * already fired or someone else deleted it. Just drop ref
1296 * and move to next entry.
1297 */
1298 if (net_eq(nf_ct_net(tmp), net) &&
1299 nf_ct_is_confirmed(tmp) &&
1300 nf_ct_delete(tmp, 0, 0))
1301 drops++;
1302
1303 nf_ct_put(tmp);
1304 }
1305
1306 return drops;
1307 }
1308
early_drop(struct net * net,unsigned int hash)1309 static noinline int early_drop(struct net *net, unsigned int hash)
1310 {
1311 unsigned int i, bucket;
1312
1313 for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
1314 struct hlist_nulls_head *ct_hash;
1315 unsigned int hsize, drops;
1316
1317 rcu_read_lock();
1318 nf_conntrack_get_ht(&ct_hash, &hsize);
1319 if (!i)
1320 bucket = reciprocal_scale(hash, hsize);
1321 else
1322 bucket = (bucket + 1) % hsize;
1323
1324 drops = early_drop_list(net, &ct_hash[bucket]);
1325 rcu_read_unlock();
1326
1327 if (drops) {
1328 NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
1329 return true;
1330 }
1331 }
1332
1333 return false;
1334 }
1335
gc_worker_skip_ct(const struct nf_conn * ct)1336 static bool gc_worker_skip_ct(const struct nf_conn *ct)
1337 {
1338 return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct);
1339 }
1340
gc_worker_can_early_drop(const struct nf_conn * ct)1341 static bool gc_worker_can_early_drop(const struct nf_conn *ct)
1342 {
1343 const struct nf_conntrack_l4proto *l4proto;
1344
1345 if (!test_bit(IPS_ASSURED_BIT, &ct->status))
1346 return true;
1347
1348 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1349 if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
1350 return true;
1351
1352 return false;
1353 }
1354
gc_worker(struct work_struct * work)1355 static void gc_worker(struct work_struct *work)
1356 {
1357 unsigned int min_interval = max(HZ / GC_MAX_BUCKETS_DIV, 1u);
1358 unsigned int i, goal, buckets = 0, expired_count = 0;
1359 unsigned int nf_conntrack_max95 = 0;
1360 struct conntrack_gc_work *gc_work;
1361 unsigned int ratio, scanned = 0;
1362 unsigned long next_run;
1363
1364 gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
1365
1366 goal = nf_conntrack_htable_size / GC_MAX_BUCKETS_DIV;
1367 i = gc_work->last_bucket;
1368 if (gc_work->early_drop)
1369 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u;
1370
1371 do {
1372 struct nf_conntrack_tuple_hash *h;
1373 struct hlist_nulls_head *ct_hash;
1374 struct hlist_nulls_node *n;
1375 unsigned int hashsz;
1376 struct nf_conn *tmp;
1377
1378 i++;
1379 rcu_read_lock();
1380
1381 nf_conntrack_get_ht(&ct_hash, &hashsz);
1382 if (i >= hashsz)
1383 i = 0;
1384
1385 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
1386 struct nf_conntrack_net *cnet;
1387 struct net *net;
1388
1389 tmp = nf_ct_tuplehash_to_ctrack(h);
1390
1391 scanned++;
1392 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) {
1393 nf_ct_offload_timeout(tmp);
1394 continue;
1395 }
1396
1397 if (nf_ct_is_expired(tmp)) {
1398 nf_ct_gc_expired(tmp);
1399 expired_count++;
1400 continue;
1401 }
1402
1403 if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp))
1404 continue;
1405
1406 net = nf_ct_net(tmp);
1407 cnet = net_generic(net, nf_conntrack_net_id);
1408 if (atomic_read(&cnet->count) < nf_conntrack_max95)
1409 continue;
1410
1411 /* need to take reference to avoid possible races */
1412 if (!atomic_inc_not_zero(&tmp->ct_general.use))
1413 continue;
1414
1415 if (gc_worker_skip_ct(tmp)) {
1416 nf_ct_put(tmp);
1417 continue;
1418 }
1419
1420 if (gc_worker_can_early_drop(tmp))
1421 nf_ct_kill(tmp);
1422
1423 nf_ct_put(tmp);
1424 }
1425
1426 /* could check get_nulls_value() here and restart if ct
1427 * was moved to another chain. But given gc is best-effort
1428 * we will just continue with next hash slot.
1429 */
1430 rcu_read_unlock();
1431 cond_resched();
1432 } while (++buckets < goal);
1433
1434 if (gc_work->exiting)
1435 return;
1436
1437 /*
1438 * Eviction will normally happen from the packet path, and not
1439 * from this gc worker.
1440 *
1441 * This worker is only here to reap expired entries when system went
1442 * idle after a busy period.
1443 *
1444 * The heuristics below are supposed to balance conflicting goals:
1445 *
1446 * 1. Minimize time until we notice a stale entry
1447 * 2. Maximize scan intervals to not waste cycles
1448 *
1449 * Normally, expire ratio will be close to 0.
1450 *
1451 * As soon as a sizeable fraction of the entries have expired
1452 * increase scan frequency.
1453 */
1454 ratio = scanned ? expired_count * 100 / scanned : 0;
1455 if (ratio > GC_EVICT_RATIO) {
1456 gc_work->next_gc_run = min_interval;
1457 } else {
1458 unsigned int max = GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV;
1459
1460 BUILD_BUG_ON((GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV) == 0);
1461
1462 gc_work->next_gc_run += min_interval;
1463 if (gc_work->next_gc_run > max)
1464 gc_work->next_gc_run = max;
1465 }
1466
1467 next_run = gc_work->next_gc_run;
1468 gc_work->last_bucket = i;
1469 gc_work->early_drop = false;
1470 queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run);
1471 }
1472
conntrack_gc_work_init(struct conntrack_gc_work * gc_work)1473 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1474 {
1475 INIT_DEFERRABLE_WORK(&gc_work->dwork, gc_worker);
1476 gc_work->next_gc_run = HZ;
1477 gc_work->exiting = false;
1478 }
1479
1480 static struct nf_conn *
__nf_conntrack_alloc(struct net * net,const struct nf_conntrack_zone * zone,const struct nf_conntrack_tuple * orig,const struct nf_conntrack_tuple * repl,gfp_t gfp,u32 hash)1481 __nf_conntrack_alloc(struct net *net,
1482 const struct nf_conntrack_zone *zone,
1483 const struct nf_conntrack_tuple *orig,
1484 const struct nf_conntrack_tuple *repl,
1485 gfp_t gfp, u32 hash)
1486 {
1487 struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
1488 unsigned int ct_count;
1489 struct nf_conn *ct;
1490
1491 /* We don't want any race condition at early drop stage */
1492 ct_count = atomic_inc_return(&cnet->count);
1493
1494 if (nf_conntrack_max && unlikely(ct_count > nf_conntrack_max)) {
1495 if (!early_drop(net, hash)) {
1496 if (!conntrack_gc_work.early_drop)
1497 conntrack_gc_work.early_drop = true;
1498 atomic_dec(&cnet->count);
1499 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1500 return ERR_PTR(-ENOMEM);
1501 }
1502 }
1503
1504 /*
1505 * Do not use kmem_cache_zalloc(), as this cache uses
1506 * SLAB_TYPESAFE_BY_RCU.
1507 */
1508 ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1509 if (ct == NULL)
1510 goto out;
1511
1512 spin_lock_init(&ct->lock);
1513 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1514 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1515 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1516 /* save hash for reusing when confirming */
1517 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1518 ct->status = 0;
1519 ct->timeout = 0;
1520 write_pnet(&ct->ct_net, net);
1521 memset(&ct->__nfct_init_offset, 0,
1522 offsetof(struct nf_conn, proto) -
1523 offsetof(struct nf_conn, __nfct_init_offset));
1524
1525 nf_ct_zone_add(ct, zone);
1526
1527 /* Because we use RCU lookups, we set ct_general.use to zero before
1528 * this is inserted in any list.
1529 */
1530 atomic_set(&ct->ct_general.use, 0);
1531 return ct;
1532 out:
1533 atomic_dec(&cnet->count);
1534 return ERR_PTR(-ENOMEM);
1535 }
1536
nf_conntrack_alloc(struct net * net,const struct nf_conntrack_zone * zone,const struct nf_conntrack_tuple * orig,const struct nf_conntrack_tuple * repl,gfp_t gfp)1537 struct nf_conn *nf_conntrack_alloc(struct net *net,
1538 const struct nf_conntrack_zone *zone,
1539 const struct nf_conntrack_tuple *orig,
1540 const struct nf_conntrack_tuple *repl,
1541 gfp_t gfp)
1542 {
1543 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1544 }
1545 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1546
nf_conntrack_free(struct nf_conn * ct)1547 void nf_conntrack_free(struct nf_conn *ct)
1548 {
1549 struct net *net = nf_ct_net(ct);
1550 struct nf_conntrack_net *cnet;
1551
1552 /* A freed object has refcnt == 0, that's
1553 * the golden rule for SLAB_TYPESAFE_BY_RCU
1554 */
1555 WARN_ON(atomic_read(&ct->ct_general.use) != 0);
1556
1557 nf_ct_ext_destroy(ct);
1558 kmem_cache_free(nf_conntrack_cachep, ct);
1559 cnet = net_generic(net, nf_conntrack_net_id);
1560
1561 smp_mb__before_atomic();
1562 atomic_dec(&cnet->count);
1563 }
1564 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1565
1566
1567 /* Allocate a new conntrack: we return -ENOMEM if classification
1568 failed due to stress. Otherwise it really is unclassifiable. */
1569 static noinline struct nf_conntrack_tuple_hash *
init_conntrack(struct net * net,struct nf_conn * tmpl,const struct nf_conntrack_tuple * tuple,struct sk_buff * skb,unsigned int dataoff,u32 hash)1570 init_conntrack(struct net *net, struct nf_conn *tmpl,
1571 const struct nf_conntrack_tuple *tuple,
1572 struct sk_buff *skb,
1573 unsigned int dataoff, u32 hash)
1574 {
1575 struct nf_conn *ct;
1576 struct nf_conn_help *help;
1577 struct nf_conntrack_tuple repl_tuple;
1578 struct nf_conntrack_ecache *ecache;
1579 struct nf_conntrack_expect *exp = NULL;
1580 const struct nf_conntrack_zone *zone;
1581 struct nf_conn_timeout *timeout_ext;
1582 struct nf_conntrack_zone tmp;
1583 struct nf_conntrack_net *cnet;
1584
1585 if (!nf_ct_invert_tuple(&repl_tuple, tuple)) {
1586 pr_debug("Can't invert tuple.\n");
1587 return NULL;
1588 }
1589
1590 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1591 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1592 hash);
1593 if (IS_ERR(ct))
1594 return (struct nf_conntrack_tuple_hash *)ct;
1595
1596 if (!nf_ct_add_synproxy(ct, tmpl)) {
1597 nf_conntrack_free(ct);
1598 return ERR_PTR(-ENOMEM);
1599 }
1600
1601 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1602
1603 if (timeout_ext)
1604 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1605 GFP_ATOMIC);
1606
1607 nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1608 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1609 nf_ct_labels_ext_add(ct);
1610
1611 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1612 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1613 ecache ? ecache->expmask : 0,
1614 GFP_ATOMIC);
1615
1616 local_bh_disable();
1617 cnet = net_generic(net, nf_conntrack_net_id);
1618 if (cnet->expect_count) {
1619 spin_lock(&nf_conntrack_expect_lock);
1620 exp = nf_ct_find_expectation(net, zone, tuple);
1621 if (exp) {
1622 pr_debug("expectation arrives ct=%p exp=%p\n",
1623 ct, exp);
1624 /* Welcome, Mr. Bond. We've been expecting you... */
1625 __set_bit(IPS_EXPECTED_BIT, &ct->status);
1626 /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1627 ct->master = exp->master;
1628 if (exp->helper) {
1629 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
1630 if (help)
1631 rcu_assign_pointer(help->helper, exp->helper);
1632 }
1633
1634 #ifdef CONFIG_NF_CONNTRACK_MARK
1635 ct->mark = exp->master->mark;
1636 #endif
1637 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1638 ct->secmark = exp->master->secmark;
1639 #endif
1640 NF_CT_STAT_INC(net, expect_new);
1641 }
1642 spin_unlock(&nf_conntrack_expect_lock);
1643 }
1644 if (!exp)
1645 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
1646
1647 /* Now it is inserted into the unconfirmed list, bump refcount */
1648 nf_conntrack_get(&ct->ct_general);
1649 nf_ct_add_to_unconfirmed_list(ct);
1650
1651 local_bh_enable();
1652
1653 if (exp) {
1654 if (exp->expectfn)
1655 exp->expectfn(ct, exp);
1656 nf_ct_expect_put(exp);
1657 }
1658
1659 return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1660 }
1661
1662 /* On success, returns 0, sets skb->_nfct | ctinfo */
1663 static int
resolve_normal_ct(struct nf_conn * tmpl,struct sk_buff * skb,unsigned int dataoff,u_int8_t protonum,const struct nf_hook_state * state)1664 resolve_normal_ct(struct nf_conn *tmpl,
1665 struct sk_buff *skb,
1666 unsigned int dataoff,
1667 u_int8_t protonum,
1668 const struct nf_hook_state *state)
1669 {
1670 const struct nf_conntrack_zone *zone;
1671 struct nf_conntrack_tuple tuple;
1672 struct nf_conntrack_tuple_hash *h;
1673 enum ip_conntrack_info ctinfo;
1674 struct nf_conntrack_zone tmp;
1675 struct nf_conn *ct;
1676 u32 hash;
1677
1678 if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1679 dataoff, state->pf, protonum, state->net,
1680 &tuple)) {
1681 pr_debug("Can't get tuple\n");
1682 return 0;
1683 }
1684
1685 /* look for tuple match */
1686 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1687 hash = hash_conntrack_raw(&tuple, state->net);
1688 h = __nf_conntrack_find_get(state->net, zone, &tuple, hash);
1689 if (!h) {
1690 h = init_conntrack(state->net, tmpl, &tuple,
1691 skb, dataoff, hash);
1692 if (!h)
1693 return 0;
1694 if (IS_ERR(h))
1695 return PTR_ERR(h);
1696 }
1697 ct = nf_ct_tuplehash_to_ctrack(h);
1698
1699 /* It exists; we have (non-exclusive) reference. */
1700 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1701 ctinfo = IP_CT_ESTABLISHED_REPLY;
1702 } else {
1703 /* Once we've had two way comms, always ESTABLISHED. */
1704 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1705 pr_debug("normal packet for %p\n", ct);
1706 ctinfo = IP_CT_ESTABLISHED;
1707 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1708 pr_debug("related packet for %p\n", ct);
1709 ctinfo = IP_CT_RELATED;
1710 } else {
1711 pr_debug("new packet for %p\n", ct);
1712 ctinfo = IP_CT_NEW;
1713 }
1714 }
1715 nf_ct_set(skb, ct, ctinfo);
1716 return 0;
1717 }
1718
1719 /*
1720 * icmp packets need special treatment to handle error messages that are
1721 * related to a connection.
1722 *
1723 * Callers need to check if skb has a conntrack assigned when this
1724 * helper returns; in such case skb belongs to an already known connection.
1725 */
1726 static unsigned int __cold
nf_conntrack_handle_icmp(struct nf_conn * tmpl,struct sk_buff * skb,unsigned int dataoff,u8 protonum,const struct nf_hook_state * state)1727 nf_conntrack_handle_icmp(struct nf_conn *tmpl,
1728 struct sk_buff *skb,
1729 unsigned int dataoff,
1730 u8 protonum,
1731 const struct nf_hook_state *state)
1732 {
1733 int ret;
1734
1735 if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP)
1736 ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state);
1737 #if IS_ENABLED(CONFIG_IPV6)
1738 else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6)
1739 ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state);
1740 #endif
1741 else
1742 return NF_ACCEPT;
1743
1744 if (ret <= 0)
1745 NF_CT_STAT_INC_ATOMIC(state->net, error);
1746
1747 return ret;
1748 }
1749
generic_packet(struct nf_conn * ct,struct sk_buff * skb,enum ip_conntrack_info ctinfo)1750 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb,
1751 enum ip_conntrack_info ctinfo)
1752 {
1753 const unsigned int *timeout = nf_ct_timeout_lookup(ct);
1754
1755 if (!timeout)
1756 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout;
1757
1758 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
1759 return NF_ACCEPT;
1760 }
1761
1762 /* Returns verdict for packet, or -1 for invalid. */
nf_conntrack_handle_packet(struct nf_conn * ct,struct sk_buff * skb,unsigned int dataoff,enum ip_conntrack_info ctinfo,const struct nf_hook_state * state)1763 static int nf_conntrack_handle_packet(struct nf_conn *ct,
1764 struct sk_buff *skb,
1765 unsigned int dataoff,
1766 enum ip_conntrack_info ctinfo,
1767 const struct nf_hook_state *state)
1768 {
1769 switch (nf_ct_protonum(ct)) {
1770 case IPPROTO_TCP:
1771 return nf_conntrack_tcp_packet(ct, skb, dataoff,
1772 ctinfo, state);
1773 case IPPROTO_UDP:
1774 return nf_conntrack_udp_packet(ct, skb, dataoff,
1775 ctinfo, state);
1776 case IPPROTO_ICMP:
1777 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state);
1778 #if IS_ENABLED(CONFIG_IPV6)
1779 case IPPROTO_ICMPV6:
1780 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state);
1781 #endif
1782 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
1783 case IPPROTO_UDPLITE:
1784 return nf_conntrack_udplite_packet(ct, skb, dataoff,
1785 ctinfo, state);
1786 #endif
1787 #ifdef CONFIG_NF_CT_PROTO_SCTP
1788 case IPPROTO_SCTP:
1789 return nf_conntrack_sctp_packet(ct, skb, dataoff,
1790 ctinfo, state);
1791 #endif
1792 #ifdef CONFIG_NF_CT_PROTO_DCCP
1793 case IPPROTO_DCCP:
1794 return nf_conntrack_dccp_packet(ct, skb, dataoff,
1795 ctinfo, state);
1796 #endif
1797 #ifdef CONFIG_NF_CT_PROTO_GRE
1798 case IPPROTO_GRE:
1799 return nf_conntrack_gre_packet(ct, skb, dataoff,
1800 ctinfo, state);
1801 #endif
1802 }
1803
1804 return generic_packet(ct, skb, ctinfo);
1805 }
1806
1807 unsigned int
nf_conntrack_in(struct sk_buff * skb,const struct nf_hook_state * state)1808 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state)
1809 {
1810 enum ip_conntrack_info ctinfo;
1811 struct nf_conn *ct, *tmpl;
1812 u_int8_t protonum;
1813 int dataoff, ret;
1814
1815 tmpl = nf_ct_get(skb, &ctinfo);
1816 if (tmpl || ctinfo == IP_CT_UNTRACKED) {
1817 /* Previously seen (loopback or untracked)? Ignore. */
1818 if ((tmpl && !nf_ct_is_template(tmpl)) ||
1819 ctinfo == IP_CT_UNTRACKED)
1820 return NF_ACCEPT;
1821 skb->_nfct = 0;
1822 }
1823
1824 /* rcu_read_lock()ed by nf_hook_thresh */
1825 dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum);
1826 if (dataoff <= 0) {
1827 pr_debug("not prepared to track yet or error occurred\n");
1828 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1829 ret = NF_ACCEPT;
1830 goto out;
1831 }
1832
1833 if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) {
1834 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff,
1835 protonum, state);
1836 if (ret <= 0) {
1837 ret = -ret;
1838 goto out;
1839 }
1840 /* ICMP[v6] protocol trackers may assign one conntrack. */
1841 if (skb->_nfct)
1842 goto out;
1843 }
1844 repeat:
1845 ret = resolve_normal_ct(tmpl, skb, dataoff,
1846 protonum, state);
1847 if (ret < 0) {
1848 /* Too stressed to deal. */
1849 NF_CT_STAT_INC_ATOMIC(state->net, drop);
1850 ret = NF_DROP;
1851 goto out;
1852 }
1853
1854 ct = nf_ct_get(skb, &ctinfo);
1855 if (!ct) {
1856 /* Not valid part of a connection */
1857 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1858 ret = NF_ACCEPT;
1859 goto out;
1860 }
1861
1862 ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state);
1863 if (ret <= 0) {
1864 /* Invalid: inverse of the return code tells
1865 * the netfilter core what to do */
1866 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1867 nf_conntrack_put(&ct->ct_general);
1868 skb->_nfct = 0;
1869 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1870 if (ret == -NF_DROP)
1871 NF_CT_STAT_INC_ATOMIC(state->net, drop);
1872 /* Special case: TCP tracker reports an attempt to reopen a
1873 * closed/aborted connection. We have to go back and create a
1874 * fresh conntrack.
1875 */
1876 if (ret == -NF_REPEAT)
1877 goto repeat;
1878 ret = -ret;
1879 goto out;
1880 }
1881
1882 if (ctinfo == IP_CT_ESTABLISHED_REPLY &&
1883 !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1884 nf_conntrack_event_cache(IPCT_REPLY, ct);
1885 out:
1886 if (tmpl)
1887 nf_ct_put(tmpl);
1888
1889 return ret;
1890 }
1891 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1892
1893 /* Alter reply tuple (maybe alter helper). This is for NAT, and is
1894 implicitly racy: see __nf_conntrack_confirm */
nf_conntrack_alter_reply(struct nf_conn * ct,const struct nf_conntrack_tuple * newreply)1895 void nf_conntrack_alter_reply(struct nf_conn *ct,
1896 const struct nf_conntrack_tuple *newreply)
1897 {
1898 struct nf_conn_help *help = nfct_help(ct);
1899
1900 /* Should be unconfirmed, so not in hash table yet */
1901 WARN_ON(nf_ct_is_confirmed(ct));
1902
1903 pr_debug("Altering reply tuple of %p to ", ct);
1904 nf_ct_dump_tuple(newreply);
1905
1906 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1907 if (ct->master || (help && !hlist_empty(&help->expectations)))
1908 return;
1909
1910 rcu_read_lock();
1911 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1912 rcu_read_unlock();
1913 }
1914 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1915
1916 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
__nf_ct_refresh_acct(struct nf_conn * ct,enum ip_conntrack_info ctinfo,const struct sk_buff * skb,u32 extra_jiffies,bool do_acct)1917 void __nf_ct_refresh_acct(struct nf_conn *ct,
1918 enum ip_conntrack_info ctinfo,
1919 const struct sk_buff *skb,
1920 u32 extra_jiffies,
1921 bool do_acct)
1922 {
1923 /* Only update if this is not a fixed timeout */
1924 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1925 goto acct;
1926
1927 /* If not in hash table, timer will not be active yet */
1928 if (nf_ct_is_confirmed(ct))
1929 extra_jiffies += nfct_time_stamp;
1930
1931 if (READ_ONCE(ct->timeout) != extra_jiffies)
1932 WRITE_ONCE(ct->timeout, extra_jiffies);
1933 acct:
1934 if (do_acct)
1935 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
1936 }
1937 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1938
nf_ct_kill_acct(struct nf_conn * ct,enum ip_conntrack_info ctinfo,const struct sk_buff * skb)1939 bool nf_ct_kill_acct(struct nf_conn *ct,
1940 enum ip_conntrack_info ctinfo,
1941 const struct sk_buff *skb)
1942 {
1943 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
1944
1945 return nf_ct_delete(ct, 0, 0);
1946 }
1947 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
1948
1949 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1950
1951 #include <linux/netfilter/nfnetlink.h>
1952 #include <linux/netfilter/nfnetlink_conntrack.h>
1953 #include <linux/mutex.h>
1954
1955 /* Generic function for tcp/udp/sctp/dccp and alike. */
nf_ct_port_tuple_to_nlattr(struct sk_buff * skb,const struct nf_conntrack_tuple * tuple)1956 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1957 const struct nf_conntrack_tuple *tuple)
1958 {
1959 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1960 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1961 goto nla_put_failure;
1962 return 0;
1963
1964 nla_put_failure:
1965 return -1;
1966 }
1967 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1968
1969 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1970 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
1971 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
1972 };
1973 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1974
nf_ct_port_nlattr_to_tuple(struct nlattr * tb[],struct nf_conntrack_tuple * t,u_int32_t flags)1975 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1976 struct nf_conntrack_tuple *t,
1977 u_int32_t flags)
1978 {
1979 if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) {
1980 if (!tb[CTA_PROTO_SRC_PORT])
1981 return -EINVAL;
1982
1983 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1984 }
1985
1986 if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) {
1987 if (!tb[CTA_PROTO_DST_PORT])
1988 return -EINVAL;
1989
1990 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1991 }
1992
1993 return 0;
1994 }
1995 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1996
nf_ct_port_nlattr_tuple_size(void)1997 unsigned int nf_ct_port_nlattr_tuple_size(void)
1998 {
1999 static unsigned int size __read_mostly;
2000
2001 if (!size)
2002 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
2003
2004 return size;
2005 }
2006 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
2007 #endif
2008
2009 /* Used by ipt_REJECT and ip6t_REJECT. */
nf_conntrack_attach(struct sk_buff * nskb,const struct sk_buff * skb)2010 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
2011 {
2012 struct nf_conn *ct;
2013 enum ip_conntrack_info ctinfo;
2014
2015 /* This ICMP is in reverse direction to the packet which caused it */
2016 ct = nf_ct_get(skb, &ctinfo);
2017 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
2018 ctinfo = IP_CT_RELATED_REPLY;
2019 else
2020 ctinfo = IP_CT_RELATED;
2021
2022 /* Attach to new skbuff, and increment count */
2023 nf_ct_set(nskb, ct, ctinfo);
2024 nf_conntrack_get(skb_nfct(nskb));
2025 }
2026
__nf_conntrack_update(struct net * net,struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info ctinfo)2027 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb,
2028 struct nf_conn *ct,
2029 enum ip_conntrack_info ctinfo)
2030 {
2031 struct nf_conntrack_tuple_hash *h;
2032 struct nf_conntrack_tuple tuple;
2033 struct nf_nat_hook *nat_hook;
2034 unsigned int status;
2035 int dataoff;
2036 u16 l3num;
2037 u8 l4num;
2038
2039 l3num = nf_ct_l3num(ct);
2040
2041 dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
2042 if (dataoff <= 0)
2043 return -1;
2044
2045 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
2046 l4num, net, &tuple))
2047 return -1;
2048
2049 if (ct->status & IPS_SRC_NAT) {
2050 memcpy(tuple.src.u3.all,
2051 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all,
2052 sizeof(tuple.src.u3.all));
2053 tuple.src.u.all =
2054 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all;
2055 }
2056
2057 if (ct->status & IPS_DST_NAT) {
2058 memcpy(tuple.dst.u3.all,
2059 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all,
2060 sizeof(tuple.dst.u3.all));
2061 tuple.dst.u.all =
2062 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all;
2063 }
2064
2065 h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple);
2066 if (!h)
2067 return 0;
2068
2069 /* Store status bits of the conntrack that is clashing to re-do NAT
2070 * mangling according to what it has been done already to this packet.
2071 */
2072 status = ct->status;
2073
2074 nf_ct_put(ct);
2075 ct = nf_ct_tuplehash_to_ctrack(h);
2076 nf_ct_set(skb, ct, ctinfo);
2077
2078 nat_hook = rcu_dereference(nf_nat_hook);
2079 if (!nat_hook)
2080 return 0;
2081
2082 if (status & IPS_SRC_NAT &&
2083 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC,
2084 IP_CT_DIR_ORIGINAL) == NF_DROP)
2085 return -1;
2086
2087 if (status & IPS_DST_NAT &&
2088 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST,
2089 IP_CT_DIR_ORIGINAL) == NF_DROP)
2090 return -1;
2091
2092 return 0;
2093 }
2094
2095 /* This packet is coming from userspace via nf_queue, complete the packet
2096 * processing after the helper invocation in nf_confirm().
2097 */
nf_confirm_cthelper(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info ctinfo)2098 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct,
2099 enum ip_conntrack_info ctinfo)
2100 {
2101 const struct nf_conntrack_helper *helper;
2102 const struct nf_conn_help *help;
2103 int protoff;
2104
2105 help = nfct_help(ct);
2106 if (!help)
2107 return 0;
2108
2109 helper = rcu_dereference(help->helper);
2110 if (!(helper->flags & NF_CT_HELPER_F_USERSPACE))
2111 return 0;
2112
2113 switch (nf_ct_l3num(ct)) {
2114 case NFPROTO_IPV4:
2115 protoff = skb_network_offset(skb) + ip_hdrlen(skb);
2116 break;
2117 #if IS_ENABLED(CONFIG_IPV6)
2118 case NFPROTO_IPV6: {
2119 __be16 frag_off;
2120 u8 pnum;
2121
2122 pnum = ipv6_hdr(skb)->nexthdr;
2123 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
2124 &frag_off);
2125 if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
2126 return 0;
2127 break;
2128 }
2129 #endif
2130 default:
2131 return 0;
2132 }
2133
2134 if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
2135 !nf_is_loopback_packet(skb)) {
2136 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
2137 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
2138 return -1;
2139 }
2140 }
2141
2142 /* We've seen it coming out the other side: confirm it */
2143 return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0;
2144 }
2145
nf_conntrack_update(struct net * net,struct sk_buff * skb)2146 static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
2147 {
2148 enum ip_conntrack_info ctinfo;
2149 struct nf_conn *ct;
2150 int err;
2151
2152 ct = nf_ct_get(skb, &ctinfo);
2153 if (!ct)
2154 return 0;
2155
2156 if (!nf_ct_is_confirmed(ct)) {
2157 err = __nf_conntrack_update(net, skb, ct, ctinfo);
2158 if (err < 0)
2159 return err;
2160
2161 ct = nf_ct_get(skb, &ctinfo);
2162 }
2163
2164 return nf_confirm_cthelper(skb, ct, ctinfo);
2165 }
2166
nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple * dst_tuple,const struct sk_buff * skb)2167 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
2168 const struct sk_buff *skb)
2169 {
2170 const struct nf_conntrack_tuple *src_tuple;
2171 const struct nf_conntrack_tuple_hash *hash;
2172 struct nf_conntrack_tuple srctuple;
2173 enum ip_conntrack_info ctinfo;
2174 struct nf_conn *ct;
2175
2176 ct = nf_ct_get(skb, &ctinfo);
2177 if (ct) {
2178 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo));
2179 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2180 return true;
2181 }
2182
2183 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
2184 NFPROTO_IPV4, dev_net(skb->dev),
2185 &srctuple))
2186 return false;
2187
2188 hash = nf_conntrack_find_get(dev_net(skb->dev),
2189 &nf_ct_zone_dflt,
2190 &srctuple);
2191 if (!hash)
2192 return false;
2193
2194 ct = nf_ct_tuplehash_to_ctrack(hash);
2195 src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir);
2196 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2197 nf_ct_put(ct);
2198
2199 return true;
2200 }
2201
2202 /* Bring out ya dead! */
2203 static struct nf_conn *
get_next_corpse(int (* iter)(struct nf_conn * i,void * data),void * data,unsigned int * bucket)2204 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
2205 void *data, unsigned int *bucket)
2206 {
2207 struct nf_conntrack_tuple_hash *h;
2208 struct nf_conn *ct;
2209 struct hlist_nulls_node *n;
2210 spinlock_t *lockp;
2211
2212 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
2213 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
2214 local_bh_disable();
2215 nf_conntrack_lock(lockp);
2216 if (*bucket < nf_conntrack_htable_size) {
2217 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnnode) {
2218 if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY)
2219 continue;
2220 /* All nf_conn objects are added to hash table twice, one
2221 * for original direction tuple, once for the reply tuple.
2222 *
2223 * Exception: In the IPS_NAT_CLASH case, only the reply
2224 * tuple is added (the original tuple already existed for
2225 * a different object).
2226 *
2227 * We only need to call the iterator once for each
2228 * conntrack, so we just use the 'reply' direction
2229 * tuple while iterating.
2230 */
2231 ct = nf_ct_tuplehash_to_ctrack(h);
2232 if (iter(ct, data))
2233 goto found;
2234 }
2235 }
2236 spin_unlock(lockp);
2237 local_bh_enable();
2238 cond_resched();
2239 }
2240
2241 return NULL;
2242 found:
2243 atomic_inc(&ct->ct_general.use);
2244 spin_unlock(lockp);
2245 local_bh_enable();
2246 return ct;
2247 }
2248
nf_ct_iterate_cleanup(int (* iter)(struct nf_conn * i,void * data),void * data,u32 portid,int report)2249 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data),
2250 void *data, u32 portid, int report)
2251 {
2252 unsigned int bucket = 0, sequence;
2253 struct nf_conn *ct;
2254
2255 might_sleep();
2256
2257 for (;;) {
2258 sequence = read_seqcount_begin(&nf_conntrack_generation);
2259
2260 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
2261 /* Time to push up daises... */
2262
2263 nf_ct_delete(ct, portid, report);
2264 nf_ct_put(ct);
2265 cond_resched();
2266 }
2267
2268 if (!read_seqcount_retry(&nf_conntrack_generation, sequence))
2269 break;
2270 bucket = 0;
2271 }
2272 }
2273
2274 struct iter_data {
2275 int (*iter)(struct nf_conn *i, void *data);
2276 void *data;
2277 struct net *net;
2278 };
2279
iter_net_only(struct nf_conn * i,void * data)2280 static int iter_net_only(struct nf_conn *i, void *data)
2281 {
2282 struct iter_data *d = data;
2283
2284 if (!net_eq(d->net, nf_ct_net(i)))
2285 return 0;
2286
2287 return d->iter(i, d->data);
2288 }
2289
2290 static void
__nf_ct_unconfirmed_destroy(struct net * net)2291 __nf_ct_unconfirmed_destroy(struct net *net)
2292 {
2293 int cpu;
2294
2295 for_each_possible_cpu(cpu) {
2296 struct nf_conntrack_tuple_hash *h;
2297 struct hlist_nulls_node *n;
2298 struct ct_pcpu *pcpu;
2299
2300 pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2301
2302 spin_lock_bh(&pcpu->lock);
2303 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
2304 struct nf_conn *ct;
2305
2306 ct = nf_ct_tuplehash_to_ctrack(h);
2307
2308 /* we cannot call iter() on unconfirmed list, the
2309 * owning cpu can reallocate ct->ext at any time.
2310 */
2311 set_bit(IPS_DYING_BIT, &ct->status);
2312 }
2313 spin_unlock_bh(&pcpu->lock);
2314 cond_resched();
2315 }
2316 }
2317
nf_ct_unconfirmed_destroy(struct net * net)2318 void nf_ct_unconfirmed_destroy(struct net *net)
2319 {
2320 struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
2321
2322 might_sleep();
2323
2324 if (atomic_read(&cnet->count) > 0) {
2325 __nf_ct_unconfirmed_destroy(net);
2326 nf_queue_nf_hook_drop(net);
2327 synchronize_net();
2328 }
2329 }
2330 EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy);
2331
nf_ct_iterate_cleanup_net(struct net * net,int (* iter)(struct nf_conn * i,void * data),void * data,u32 portid,int report)2332 void nf_ct_iterate_cleanup_net(struct net *net,
2333 int (*iter)(struct nf_conn *i, void *data),
2334 void *data, u32 portid, int report)
2335 {
2336 struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
2337 struct iter_data d;
2338
2339 might_sleep();
2340
2341 if (atomic_read(&cnet->count) == 0)
2342 return;
2343
2344 d.iter = iter;
2345 d.data = data;
2346 d.net = net;
2347
2348 nf_ct_iterate_cleanup(iter_net_only, &d, portid, report);
2349 }
2350 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net);
2351
2352 /**
2353 * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table
2354 * @iter: callback to invoke for each conntrack
2355 * @data: data to pass to @iter
2356 *
2357 * Like nf_ct_iterate_cleanup, but first marks conntracks on the
2358 * unconfirmed list as dying (so they will not be inserted into
2359 * main table).
2360 *
2361 * Can only be called in module exit path.
2362 */
2363 void
nf_ct_iterate_destroy(int (* iter)(struct nf_conn * i,void * data),void * data)2364 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
2365 {
2366 struct net *net;
2367
2368 down_read(&net_rwsem);
2369 for_each_net(net) {
2370 struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
2371
2372 if (atomic_read(&cnet->count) == 0)
2373 continue;
2374 __nf_ct_unconfirmed_destroy(net);
2375 nf_queue_nf_hook_drop(net);
2376 }
2377 up_read(&net_rwsem);
2378
2379 /* Need to wait for netns cleanup worker to finish, if its
2380 * running -- it might have deleted a net namespace from
2381 * the global list, so our __nf_ct_unconfirmed_destroy() might
2382 * not have affected all namespaces.
2383 */
2384 net_ns_barrier();
2385
2386 /* a conntrack could have been unlinked from unconfirmed list
2387 * before we grabbed pcpu lock in __nf_ct_unconfirmed_destroy().
2388 * This makes sure its inserted into conntrack table.
2389 */
2390 synchronize_net();
2391
2392 nf_ct_iterate_cleanup(iter, data, 0, 0);
2393 }
2394 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy);
2395
kill_all(struct nf_conn * i,void * data)2396 static int kill_all(struct nf_conn *i, void *data)
2397 {
2398 return net_eq(nf_ct_net(i), data);
2399 }
2400
nf_conntrack_cleanup_start(void)2401 void nf_conntrack_cleanup_start(void)
2402 {
2403 conntrack_gc_work.exiting = true;
2404 RCU_INIT_POINTER(ip_ct_attach, NULL);
2405 }
2406
nf_conntrack_cleanup_end(void)2407 void nf_conntrack_cleanup_end(void)
2408 {
2409 RCU_INIT_POINTER(nf_ct_hook, NULL);
2410 cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2411 kvfree(nf_conntrack_hash);
2412
2413 nf_conntrack_proto_fini();
2414 nf_conntrack_seqadj_fini();
2415 nf_conntrack_labels_fini();
2416 nf_conntrack_helper_fini();
2417 nf_conntrack_timeout_fini();
2418 nf_conntrack_ecache_fini();
2419 nf_conntrack_tstamp_fini();
2420 nf_conntrack_acct_fini();
2421 nf_conntrack_expect_fini();
2422
2423 kmem_cache_destroy(nf_conntrack_cachep);
2424 }
2425
2426 /*
2427 * Mishearing the voices in his head, our hero wonders how he's
2428 * supposed to kill the mall.
2429 */
nf_conntrack_cleanup_net(struct net * net)2430 void nf_conntrack_cleanup_net(struct net *net)
2431 {
2432 LIST_HEAD(single);
2433
2434 list_add(&net->exit_list, &single);
2435 nf_conntrack_cleanup_net_list(&single);
2436 }
2437
nf_conntrack_cleanup_net_list(struct list_head * net_exit_list)2438 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
2439 {
2440 int busy;
2441 struct net *net;
2442
2443 /*
2444 * This makes sure all current packets have passed through
2445 * netfilter framework. Roll on, two-stage module
2446 * delete...
2447 */
2448 synchronize_net();
2449 i_see_dead_people:
2450 busy = 0;
2451 list_for_each_entry(net, net_exit_list, exit_list) {
2452 struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
2453
2454 nf_ct_iterate_cleanup(kill_all, net, 0, 0);
2455 if (atomic_read(&cnet->count) != 0)
2456 busy = 1;
2457 }
2458 if (busy) {
2459 schedule();
2460 goto i_see_dead_people;
2461 }
2462
2463 list_for_each_entry(net, net_exit_list, exit_list) {
2464 nf_conntrack_proto_pernet_fini(net);
2465 nf_conntrack_ecache_pernet_fini(net);
2466 nf_conntrack_expect_pernet_fini(net);
2467 free_percpu(net->ct.stat);
2468 free_percpu(net->ct.pcpu_lists);
2469 }
2470 }
2471
nf_ct_alloc_hashtable(unsigned int * sizep,int nulls)2472 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
2473 {
2474 struct hlist_nulls_head *hash;
2475 unsigned int nr_slots, i;
2476
2477 if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
2478 return NULL;
2479
2480 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
2481 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
2482
2483 hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL);
2484
2485 if (hash && nulls)
2486 for (i = 0; i < nr_slots; i++)
2487 INIT_HLIST_NULLS_HEAD(&hash[i], i);
2488
2489 return hash;
2490 }
2491 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
2492
nf_conntrack_hash_resize(unsigned int hashsize)2493 int nf_conntrack_hash_resize(unsigned int hashsize)
2494 {
2495 int i, bucket;
2496 unsigned int old_size;
2497 struct hlist_nulls_head *hash, *old_hash;
2498 struct nf_conntrack_tuple_hash *h;
2499 struct nf_conn *ct;
2500
2501 if (!hashsize)
2502 return -EINVAL;
2503
2504 hash = nf_ct_alloc_hashtable(&hashsize, 1);
2505 if (!hash)
2506 return -ENOMEM;
2507
2508 old_size = nf_conntrack_htable_size;
2509 if (old_size == hashsize) {
2510 kvfree(hash);
2511 return 0;
2512 }
2513
2514 local_bh_disable();
2515 nf_conntrack_all_lock();
2516 write_seqcount_begin(&nf_conntrack_generation);
2517
2518 /* Lookups in the old hash might happen in parallel, which means we
2519 * might get false negatives during connection lookup. New connections
2520 * created because of a false negative won't make it into the hash
2521 * though since that required taking the locks.
2522 */
2523
2524 for (i = 0; i < nf_conntrack_htable_size; i++) {
2525 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
2526 h = hlist_nulls_entry(nf_conntrack_hash[i].first,
2527 struct nf_conntrack_tuple_hash, hnnode);
2528 ct = nf_ct_tuplehash_to_ctrack(h);
2529 hlist_nulls_del_rcu(&h->hnnode);
2530 bucket = __hash_conntrack(nf_ct_net(ct),
2531 &h->tuple, hashsize);
2532 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
2533 }
2534 }
2535 old_size = nf_conntrack_htable_size;
2536 old_hash = nf_conntrack_hash;
2537
2538 nf_conntrack_hash = hash;
2539 nf_conntrack_htable_size = hashsize;
2540
2541 write_seqcount_end(&nf_conntrack_generation);
2542 nf_conntrack_all_unlock();
2543 local_bh_enable();
2544
2545 synchronize_net();
2546 kvfree(old_hash);
2547 return 0;
2548 }
2549
nf_conntrack_set_hashsize(const char * val,const struct kernel_param * kp)2550 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp)
2551 {
2552 unsigned int hashsize;
2553 int rc;
2554
2555 if (current->nsproxy->net_ns != &init_net)
2556 return -EOPNOTSUPP;
2557
2558 /* On boot, we can set this without any fancy locking. */
2559 if (!nf_conntrack_hash)
2560 return param_set_uint(val, kp);
2561
2562 rc = kstrtouint(val, 0, &hashsize);
2563 if (rc)
2564 return rc;
2565
2566 return nf_conntrack_hash_resize(hashsize);
2567 }
2568
total_extension_size(void)2569 static __always_inline unsigned int total_extension_size(void)
2570 {
2571 /* remember to add new extensions below */
2572 BUILD_BUG_ON(NF_CT_EXT_NUM > 9);
2573
2574 return sizeof(struct nf_ct_ext) +
2575 sizeof(struct nf_conn_help)
2576 #if IS_ENABLED(CONFIG_NF_NAT)
2577 + sizeof(struct nf_conn_nat)
2578 #endif
2579 + sizeof(struct nf_conn_seqadj)
2580 + sizeof(struct nf_conn_acct)
2581 #ifdef CONFIG_NF_CONNTRACK_EVENTS
2582 + sizeof(struct nf_conntrack_ecache)
2583 #endif
2584 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
2585 + sizeof(struct nf_conn_tstamp)
2586 #endif
2587 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
2588 + sizeof(struct nf_conn_timeout)
2589 #endif
2590 #ifdef CONFIG_NF_CONNTRACK_LABELS
2591 + sizeof(struct nf_conn_labels)
2592 #endif
2593 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
2594 + sizeof(struct nf_conn_synproxy)
2595 #endif
2596 ;
2597 };
2598
nf_conntrack_init_start(void)2599 int nf_conntrack_init_start(void)
2600 {
2601 unsigned long nr_pages = totalram_pages();
2602 int max_factor = 8;
2603 int ret = -ENOMEM;
2604 int i;
2605
2606 /* struct nf_ct_ext uses u8 to store offsets/size */
2607 BUILD_BUG_ON(total_extension_size() > 255u);
2608
2609 seqcount_spinlock_init(&nf_conntrack_generation,
2610 &nf_conntrack_locks_all_lock);
2611
2612 for (i = 0; i < CONNTRACK_LOCKS; i++)
2613 spin_lock_init(&nf_conntrack_locks[i]);
2614
2615 if (!nf_conntrack_htable_size) {
2616 /* Idea from tcp.c: use 1/16384 of memory.
2617 * On i386: 32MB machine has 512 buckets.
2618 * >= 1GB machines have 16384 buckets.
2619 * >= 4GB machines have 65536 buckets.
2620 */
2621 nf_conntrack_htable_size
2622 = (((nr_pages << PAGE_SHIFT) / 16384)
2623 / sizeof(struct hlist_head));
2624 if (nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
2625 nf_conntrack_htable_size = 65536;
2626 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
2627 nf_conntrack_htable_size = 16384;
2628 if (nf_conntrack_htable_size < 32)
2629 nf_conntrack_htable_size = 32;
2630
2631 /* Use a max. factor of four by default to get the same max as
2632 * with the old struct list_heads. When a table size is given
2633 * we use the old value of 8 to avoid reducing the max.
2634 * entries. */
2635 max_factor = 4;
2636 }
2637
2638 nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
2639 if (!nf_conntrack_hash)
2640 return -ENOMEM;
2641
2642 nf_conntrack_max = max_factor * nf_conntrack_htable_size;
2643
2644 nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
2645 sizeof(struct nf_conn),
2646 NFCT_INFOMASK + 1,
2647 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
2648 if (!nf_conntrack_cachep)
2649 goto err_cachep;
2650
2651 ret = nf_conntrack_expect_init();
2652 if (ret < 0)
2653 goto err_expect;
2654
2655 ret = nf_conntrack_acct_init();
2656 if (ret < 0)
2657 goto err_acct;
2658
2659 ret = nf_conntrack_tstamp_init();
2660 if (ret < 0)
2661 goto err_tstamp;
2662
2663 ret = nf_conntrack_ecache_init();
2664 if (ret < 0)
2665 goto err_ecache;
2666
2667 ret = nf_conntrack_timeout_init();
2668 if (ret < 0)
2669 goto err_timeout;
2670
2671 ret = nf_conntrack_helper_init();
2672 if (ret < 0)
2673 goto err_helper;
2674
2675 ret = nf_conntrack_labels_init();
2676 if (ret < 0)
2677 goto err_labels;
2678
2679 ret = nf_conntrack_seqadj_init();
2680 if (ret < 0)
2681 goto err_seqadj;
2682
2683 ret = nf_conntrack_proto_init();
2684 if (ret < 0)
2685 goto err_proto;
2686
2687 conntrack_gc_work_init(&conntrack_gc_work);
2688 queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ);
2689
2690 return 0;
2691
2692 err_proto:
2693 nf_conntrack_seqadj_fini();
2694 err_seqadj:
2695 nf_conntrack_labels_fini();
2696 err_labels:
2697 nf_conntrack_helper_fini();
2698 err_helper:
2699 nf_conntrack_timeout_fini();
2700 err_timeout:
2701 nf_conntrack_ecache_fini();
2702 err_ecache:
2703 nf_conntrack_tstamp_fini();
2704 err_tstamp:
2705 nf_conntrack_acct_fini();
2706 err_acct:
2707 nf_conntrack_expect_fini();
2708 err_expect:
2709 kmem_cache_destroy(nf_conntrack_cachep);
2710 err_cachep:
2711 kvfree(nf_conntrack_hash);
2712 return ret;
2713 }
2714
2715 static struct nf_ct_hook nf_conntrack_hook = {
2716 .update = nf_conntrack_update,
2717 .destroy = destroy_conntrack,
2718 .get_tuple_skb = nf_conntrack_get_tuple_skb,
2719 };
2720
nf_conntrack_init_end(void)2721 void nf_conntrack_init_end(void)
2722 {
2723 /* For use by REJECT target */
2724 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
2725 RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook);
2726 }
2727
2728 /*
2729 * We need to use special "null" values, not used in hash table
2730 */
2731 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0)
2732 #define DYING_NULLS_VAL ((1<<30)+1)
2733
nf_conntrack_init_net(struct net * net)2734 int nf_conntrack_init_net(struct net *net)
2735 {
2736 struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
2737 int ret = -ENOMEM;
2738 int cpu;
2739
2740 BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER);
2741 BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS);
2742 atomic_set(&cnet->count, 0);
2743
2744 net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
2745 if (!net->ct.pcpu_lists)
2746 goto err_stat;
2747
2748 for_each_possible_cpu(cpu) {
2749 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2750
2751 spin_lock_init(&pcpu->lock);
2752 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
2753 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
2754 }
2755
2756 net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
2757 if (!net->ct.stat)
2758 goto err_pcpu_lists;
2759
2760 ret = nf_conntrack_expect_pernet_init(net);
2761 if (ret < 0)
2762 goto err_expect;
2763
2764 nf_conntrack_acct_pernet_init(net);
2765 nf_conntrack_tstamp_pernet_init(net);
2766 nf_conntrack_ecache_pernet_init(net);
2767 nf_conntrack_helper_pernet_init(net);
2768 nf_conntrack_proto_pernet_init(net);
2769
2770 return 0;
2771
2772 err_expect:
2773 free_percpu(net->ct.stat);
2774 err_pcpu_lists:
2775 free_percpu(net->ct.pcpu_lists);
2776 err_stat:
2777 return ret;
2778 }
2779