1 /* Connection state tracking for netfilter.  This is separated from,
2    but required by, the NAT layer; it can also be used by an iptables
3    extension. */
4 
5 /* (C) 1999-2001 Paul `Rusty' Russell
6  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
7  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
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/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>
32 #include <linux/mm.h>
33 #include <linux/nsproxy.h>
34 #include <linux/rculist_nulls.h>
35 
36 #include <net/netfilter/nf_conntrack.h>
37 #include <net/netfilter/nf_conntrack_l3proto.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_nat.h>
48 #include <net/netfilter/nf_nat_core.h>
49 
50 #define NF_CONNTRACK_VERSION	"0.5.0"
51 
52 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
53 				      enum nf_nat_manip_type manip,
54 				      const struct nlattr *attr) __read_mostly;
55 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
56 
57 DEFINE_SPINLOCK(nf_conntrack_lock);
58 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
59 
60 unsigned int nf_conntrack_htable_size __read_mostly;
61 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
62 
63 unsigned int nf_conntrack_max __read_mostly;
64 EXPORT_SYMBOL_GPL(nf_conntrack_max);
65 
66 DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
67 EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);
68 
69 unsigned int nf_conntrack_hash_rnd __read_mostly;
70 EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd);
71 
hash_conntrack_raw(const struct nf_conntrack_tuple * tuple,u16 zone)72 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone)
73 {
74 	unsigned int n;
75 
76 	/* The direction must be ignored, so we hash everything up to the
77 	 * destination ports (which is a multiple of 4) and treat the last
78 	 * three bytes manually.
79 	 */
80 	n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
81 	return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^
82 		      (((__force __u16)tuple->dst.u.all << 16) |
83 		      tuple->dst.protonum));
84 }
85 
__hash_bucket(u32 hash,unsigned int size)86 static u32 __hash_bucket(u32 hash, unsigned int size)
87 {
88 	return ((u64)hash * size) >> 32;
89 }
90 
hash_bucket(u32 hash,const struct net * net)91 static u32 hash_bucket(u32 hash, const struct net *net)
92 {
93 	return __hash_bucket(hash, net->ct.htable_size);
94 }
95 
__hash_conntrack(const struct nf_conntrack_tuple * tuple,u16 zone,unsigned int size)96 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
97 				  u16 zone, unsigned int size)
98 {
99 	return __hash_bucket(hash_conntrack_raw(tuple, zone), size);
100 }
101 
hash_conntrack(const struct net * net,u16 zone,const struct nf_conntrack_tuple * tuple)102 static inline u_int32_t hash_conntrack(const struct net *net, u16 zone,
103 				       const struct nf_conntrack_tuple *tuple)
104 {
105 	return __hash_conntrack(tuple, zone, net->ct.htable_size);
106 }
107 
108 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 nf_conntrack_tuple * tuple,const struct nf_conntrack_l3proto * l3proto,const struct nf_conntrack_l4proto * l4proto)109 nf_ct_get_tuple(const struct sk_buff *skb,
110 		unsigned int nhoff,
111 		unsigned int dataoff,
112 		u_int16_t l3num,
113 		u_int8_t protonum,
114 		struct nf_conntrack_tuple *tuple,
115 		const struct nf_conntrack_l3proto *l3proto,
116 		const struct nf_conntrack_l4proto *l4proto)
117 {
118 	memset(tuple, 0, sizeof(*tuple));
119 
120 	tuple->src.l3num = l3num;
121 	if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
122 		return false;
123 
124 	tuple->dst.protonum = protonum;
125 	tuple->dst.dir = IP_CT_DIR_ORIGINAL;
126 
127 	return l4proto->pkt_to_tuple(skb, dataoff, tuple);
128 }
129 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
130 
nf_ct_get_tuplepr(const struct sk_buff * skb,unsigned int nhoff,u_int16_t l3num,struct nf_conntrack_tuple * tuple)131 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
132 		       u_int16_t l3num, struct nf_conntrack_tuple *tuple)
133 {
134 	struct nf_conntrack_l3proto *l3proto;
135 	struct nf_conntrack_l4proto *l4proto;
136 	unsigned int protoff;
137 	u_int8_t protonum;
138 	int ret;
139 
140 	rcu_read_lock();
141 
142 	l3proto = __nf_ct_l3proto_find(l3num);
143 	ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
144 	if (ret != NF_ACCEPT) {
145 		rcu_read_unlock();
146 		return false;
147 	}
148 
149 	l4proto = __nf_ct_l4proto_find(l3num, protonum);
150 
151 	ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
152 			      l3proto, l4proto);
153 
154 	rcu_read_unlock();
155 	return ret;
156 }
157 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
158 
159 bool
nf_ct_invert_tuple(struct nf_conntrack_tuple * inverse,const struct nf_conntrack_tuple * orig,const struct nf_conntrack_l3proto * l3proto,const struct nf_conntrack_l4proto * l4proto)160 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
161 		   const struct nf_conntrack_tuple *orig,
162 		   const struct nf_conntrack_l3proto *l3proto,
163 		   const struct nf_conntrack_l4proto *l4proto)
164 {
165 	memset(inverse, 0, sizeof(*inverse));
166 
167 	inverse->src.l3num = orig->src.l3num;
168 	if (l3proto->invert_tuple(inverse, orig) == 0)
169 		return false;
170 
171 	inverse->dst.dir = !orig->dst.dir;
172 
173 	inverse->dst.protonum = orig->dst.protonum;
174 	return l4proto->invert_tuple(inverse, orig);
175 }
176 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
177 
178 static void
clean_from_lists(struct nf_conn * ct)179 clean_from_lists(struct nf_conn *ct)
180 {
181 	pr_debug("clean_from_lists(%p)\n", ct);
182 	hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
183 	hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
184 
185 	/* Destroy all pending expectations */
186 	nf_ct_remove_expectations(ct);
187 }
188 
189 static void
destroy_conntrack(struct nf_conntrack * nfct)190 destroy_conntrack(struct nf_conntrack *nfct)
191 {
192 	struct nf_conn *ct = (struct nf_conn *)nfct;
193 	struct net *net = nf_ct_net(ct);
194 	struct nf_conntrack_l4proto *l4proto;
195 
196 	pr_debug("destroy_conntrack(%p)\n", ct);
197 	NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
198 	NF_CT_ASSERT(!timer_pending(&ct->timeout));
199 
200 	/* To make sure we don't get any weird locking issues here:
201 	 * destroy_conntrack() MUST NOT be called with a write lock
202 	 * to nf_conntrack_lock!!! -HW */
203 	rcu_read_lock();
204 	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
205 	if (l4proto && l4proto->destroy)
206 		l4proto->destroy(ct);
207 
208 	rcu_read_unlock();
209 
210 	spin_lock_bh(&nf_conntrack_lock);
211 	/* Expectations will have been removed in clean_from_lists,
212 	 * except TFTP can create an expectation on the first packet,
213 	 * before connection is in the list, so we need to clean here,
214 	 * too. */
215 	nf_ct_remove_expectations(ct);
216 
217 	/* We overload first tuple to link into unconfirmed list. */
218 	if (!nf_ct_is_confirmed(ct)) {
219 		BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
220 		hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
221 	}
222 
223 	NF_CT_STAT_INC(net, delete);
224 	spin_unlock_bh(&nf_conntrack_lock);
225 
226 	if (ct->master)
227 		nf_ct_put(ct->master);
228 
229 	pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
230 	nf_conntrack_free(ct);
231 }
232 
nf_ct_delete_from_lists(struct nf_conn * ct)233 void nf_ct_delete_from_lists(struct nf_conn *ct)
234 {
235 	struct net *net = nf_ct_net(ct);
236 
237 	nf_ct_helper_destroy(ct);
238 	spin_lock_bh(&nf_conntrack_lock);
239 	/* Inside lock so preempt is disabled on module removal path.
240 	 * Otherwise we can get spurious warnings. */
241 	NF_CT_STAT_INC(net, delete_list);
242 	clean_from_lists(ct);
243 	spin_unlock_bh(&nf_conntrack_lock);
244 }
245 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
246 
death_by_event(unsigned long ul_conntrack)247 static void death_by_event(unsigned long ul_conntrack)
248 {
249 	struct nf_conn *ct = (void *)ul_conntrack;
250 	struct net *net = nf_ct_net(ct);
251 
252 	if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
253 		/* bad luck, let's retry again */
254 		ct->timeout.expires = jiffies +
255 			(random32() % net->ct.sysctl_events_retry_timeout);
256 		add_timer(&ct->timeout);
257 		return;
258 	}
259 	/* we've got the event delivered, now it's dying */
260 	set_bit(IPS_DYING_BIT, &ct->status);
261 	spin_lock(&nf_conntrack_lock);
262 	hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
263 	spin_unlock(&nf_conntrack_lock);
264 	nf_ct_put(ct);
265 }
266 
nf_ct_insert_dying_list(struct nf_conn * ct)267 void nf_ct_insert_dying_list(struct nf_conn *ct)
268 {
269 	struct net *net = nf_ct_net(ct);
270 
271 	/* add this conntrack to the dying list */
272 	spin_lock_bh(&nf_conntrack_lock);
273 	hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
274 			     &net->ct.dying);
275 	spin_unlock_bh(&nf_conntrack_lock);
276 	/* set a new timer to retry event delivery */
277 	setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
278 	ct->timeout.expires = jiffies +
279 		(random32() % net->ct.sysctl_events_retry_timeout);
280 	add_timer(&ct->timeout);
281 }
282 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
283 
death_by_timeout(unsigned long ul_conntrack)284 static void death_by_timeout(unsigned long ul_conntrack)
285 {
286 	struct nf_conn *ct = (void *)ul_conntrack;
287 	struct nf_conn_tstamp *tstamp;
288 
289 	tstamp = nf_conn_tstamp_find(ct);
290 	if (tstamp && tstamp->stop == 0)
291 		tstamp->stop = ktime_to_ns(ktime_get_real());
292 
293 	if (!test_bit(IPS_DYING_BIT, &ct->status) &&
294 	    unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
295 		/* destroy event was not delivered */
296 		nf_ct_delete_from_lists(ct);
297 		nf_ct_insert_dying_list(ct);
298 		return;
299 	}
300 	set_bit(IPS_DYING_BIT, &ct->status);
301 	nf_ct_delete_from_lists(ct);
302 	nf_ct_put(ct);
303 }
304 
305 /*
306  * Warning :
307  * - Caller must take a reference on returned object
308  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
309  * OR
310  * - Caller must lock nf_conntrack_lock before calling this function
311  */
312 static struct nf_conntrack_tuple_hash *
____nf_conntrack_find(struct net * net,u16 zone,const struct nf_conntrack_tuple * tuple,u32 hash)313 ____nf_conntrack_find(struct net *net, u16 zone,
314 		      const struct nf_conntrack_tuple *tuple, u32 hash)
315 {
316 	struct nf_conntrack_tuple_hash *h;
317 	struct hlist_nulls_node *n;
318 	unsigned int bucket = hash_bucket(hash, net);
319 
320 	/* Disable BHs the entire time since we normally need to disable them
321 	 * at least once for the stats anyway.
322 	 */
323 	local_bh_disable();
324 begin:
325 	hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) {
326 		if (nf_ct_tuple_equal(tuple, &h->tuple) &&
327 		    nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) {
328 			NF_CT_STAT_INC(net, found);
329 			local_bh_enable();
330 			return h;
331 		}
332 		NF_CT_STAT_INC(net, searched);
333 	}
334 	/*
335 	 * if the nulls value we got at the end of this lookup is
336 	 * not the expected one, we must restart lookup.
337 	 * We probably met an item that was moved to another chain.
338 	 */
339 	if (get_nulls_value(n) != bucket) {
340 		NF_CT_STAT_INC(net, search_restart);
341 		goto begin;
342 	}
343 	local_bh_enable();
344 
345 	return NULL;
346 }
347 
348 struct nf_conntrack_tuple_hash *
__nf_conntrack_find(struct net * net,u16 zone,const struct nf_conntrack_tuple * tuple)349 __nf_conntrack_find(struct net *net, u16 zone,
350 		    const struct nf_conntrack_tuple *tuple)
351 {
352 	return ____nf_conntrack_find(net, zone, tuple,
353 				     hash_conntrack_raw(tuple, zone));
354 }
355 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
356 
357 /* Find a connection corresponding to a tuple. */
358 static struct nf_conntrack_tuple_hash *
__nf_conntrack_find_get(struct net * net,u16 zone,const struct nf_conntrack_tuple * tuple,u32 hash)359 __nf_conntrack_find_get(struct net *net, u16 zone,
360 			const struct nf_conntrack_tuple *tuple, u32 hash)
361 {
362 	struct nf_conntrack_tuple_hash *h;
363 	struct nf_conn *ct;
364 
365 	rcu_read_lock();
366 begin:
367 	h = ____nf_conntrack_find(net, zone, tuple, hash);
368 	if (h) {
369 		ct = nf_ct_tuplehash_to_ctrack(h);
370 		if (unlikely(nf_ct_is_dying(ct) ||
371 			     !atomic_inc_not_zero(&ct->ct_general.use)))
372 			h = NULL;
373 		else {
374 			if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) ||
375 				     nf_ct_zone(ct) != zone)) {
376 				nf_ct_put(ct);
377 				goto begin;
378 			}
379 		}
380 	}
381 	rcu_read_unlock();
382 
383 	return h;
384 }
385 
386 struct nf_conntrack_tuple_hash *
nf_conntrack_find_get(struct net * net,u16 zone,const struct nf_conntrack_tuple * tuple)387 nf_conntrack_find_get(struct net *net, u16 zone,
388 		      const struct nf_conntrack_tuple *tuple)
389 {
390 	return __nf_conntrack_find_get(net, zone, tuple,
391 				       hash_conntrack_raw(tuple, zone));
392 }
393 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
394 
__nf_conntrack_hash_insert(struct nf_conn * ct,unsigned int hash,unsigned int repl_hash)395 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
396 				       unsigned int hash,
397 				       unsigned int repl_hash)
398 {
399 	struct net *net = nf_ct_net(ct);
400 
401 	hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
402 			   &net->ct.hash[hash]);
403 	hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
404 			   &net->ct.hash[repl_hash]);
405 }
406 
407 int
nf_conntrack_hash_check_insert(struct nf_conn * ct)408 nf_conntrack_hash_check_insert(struct nf_conn *ct)
409 {
410 	struct net *net = nf_ct_net(ct);
411 	unsigned int hash, repl_hash;
412 	struct nf_conntrack_tuple_hash *h;
413 	struct hlist_nulls_node *n;
414 	u16 zone;
415 
416 	zone = nf_ct_zone(ct);
417 	hash = hash_conntrack(net, zone,
418 			      &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
419 	repl_hash = hash_conntrack(net, zone,
420 				   &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
421 
422 	spin_lock_bh(&nf_conntrack_lock);
423 
424 	/* See if there's one in the list already, including reverse */
425 	hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
426 		if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
427 				      &h->tuple) &&
428 		    zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
429 			goto out;
430 	hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
431 		if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
432 				      &h->tuple) &&
433 		    zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
434 			goto out;
435 
436 	add_timer(&ct->timeout);
437 	nf_conntrack_get(&ct->ct_general);
438 	__nf_conntrack_hash_insert(ct, hash, repl_hash);
439 	NF_CT_STAT_INC(net, insert);
440 	spin_unlock_bh(&nf_conntrack_lock);
441 
442 	return 0;
443 
444 out:
445 	NF_CT_STAT_INC(net, insert_failed);
446 	spin_unlock_bh(&nf_conntrack_lock);
447 	return -EEXIST;
448 }
449 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
450 
451 /* Confirm a connection given skb; places it in hash table */
452 int
__nf_conntrack_confirm(struct sk_buff * skb)453 __nf_conntrack_confirm(struct sk_buff *skb)
454 {
455 	unsigned int hash, repl_hash;
456 	struct nf_conntrack_tuple_hash *h;
457 	struct nf_conn *ct;
458 	struct nf_conn_help *help;
459 	struct nf_conn_tstamp *tstamp;
460 	struct hlist_nulls_node *n;
461 	enum ip_conntrack_info ctinfo;
462 	struct net *net;
463 	u16 zone;
464 
465 	ct = nf_ct_get(skb, &ctinfo);
466 	net = nf_ct_net(ct);
467 
468 	/* ipt_REJECT uses nf_conntrack_attach to attach related
469 	   ICMP/TCP RST packets in other direction.  Actual packet
470 	   which created connection will be IP_CT_NEW or for an
471 	   expected connection, IP_CT_RELATED. */
472 	if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
473 		return NF_ACCEPT;
474 
475 	zone = nf_ct_zone(ct);
476 	/* reuse the hash saved before */
477 	hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
478 	hash = hash_bucket(hash, net);
479 	repl_hash = hash_conntrack(net, zone,
480 				   &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
481 
482 	/* We're not in hash table, and we refuse to set up related
483 	   connections for unconfirmed conns.  But packet copies and
484 	   REJECT will give spurious warnings here. */
485 	/* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
486 
487 	/* No external references means no one else could have
488 	   confirmed us. */
489 	NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
490 	pr_debug("Confirming conntrack %p\n", ct);
491 
492 	spin_lock_bh(&nf_conntrack_lock);
493 
494 	/* We have to check the DYING flag inside the lock to prevent
495 	   a race against nf_ct_get_next_corpse() possibly called from
496 	   user context, else we insert an already 'dead' hash, blocking
497 	   further use of that particular connection -JM */
498 
499 	if (unlikely(nf_ct_is_dying(ct))) {
500 		spin_unlock_bh(&nf_conntrack_lock);
501 		return NF_ACCEPT;
502 	}
503 
504 	/* See if there's one in the list already, including reverse:
505 	   NAT could have grabbed it without realizing, since we're
506 	   not in the hash.  If there is, we lost race. */
507 	hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
508 		if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
509 				      &h->tuple) &&
510 		    zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
511 			goto out;
512 	hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
513 		if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
514 				      &h->tuple) &&
515 		    zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
516 			goto out;
517 
518 	/* Remove from unconfirmed list */
519 	hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
520 
521 	/* Timer relative to confirmation time, not original
522 	   setting time, otherwise we'd get timer wrap in
523 	   weird delay cases. */
524 	ct->timeout.expires += jiffies;
525 	add_timer(&ct->timeout);
526 	atomic_inc(&ct->ct_general.use);
527 	ct->status |= IPS_CONFIRMED;
528 
529 	/* set conntrack timestamp, if enabled. */
530 	tstamp = nf_conn_tstamp_find(ct);
531 	if (tstamp) {
532 		if (skb->tstamp.tv64 == 0)
533 			__net_timestamp((struct sk_buff *)skb);
534 
535 		tstamp->start = ktime_to_ns(skb->tstamp);
536 	}
537 	/* Since the lookup is lockless, hash insertion must be done after
538 	 * starting the timer and setting the CONFIRMED bit. The RCU barriers
539 	 * guarantee that no other CPU can find the conntrack before the above
540 	 * stores are visible.
541 	 */
542 	__nf_conntrack_hash_insert(ct, hash, repl_hash);
543 	NF_CT_STAT_INC(net, insert);
544 	spin_unlock_bh(&nf_conntrack_lock);
545 
546 	help = nfct_help(ct);
547 	if (help && help->helper)
548 		nf_conntrack_event_cache(IPCT_HELPER, ct);
549 
550 	nf_conntrack_event_cache(master_ct(ct) ?
551 				 IPCT_RELATED : IPCT_NEW, ct);
552 	return NF_ACCEPT;
553 
554 out:
555 	NF_CT_STAT_INC(net, insert_failed);
556 	spin_unlock_bh(&nf_conntrack_lock);
557 	return NF_DROP;
558 }
559 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
560 
561 /* Returns true if a connection correspondings to the tuple (required
562    for NAT). */
563 int
nf_conntrack_tuple_taken(const struct nf_conntrack_tuple * tuple,const struct nf_conn * ignored_conntrack)564 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
565 			 const struct nf_conn *ignored_conntrack)
566 {
567 	struct net *net = nf_ct_net(ignored_conntrack);
568 	struct nf_conntrack_tuple_hash *h;
569 	struct hlist_nulls_node *n;
570 	struct nf_conn *ct;
571 	u16 zone = nf_ct_zone(ignored_conntrack);
572 	unsigned int hash = hash_conntrack(net, zone, tuple);
573 
574 	/* Disable BHs the entire time since we need to disable them at
575 	 * least once for the stats anyway.
576 	 */
577 	rcu_read_lock_bh();
578 	hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
579 		ct = nf_ct_tuplehash_to_ctrack(h);
580 		if (ct != ignored_conntrack &&
581 		    nf_ct_tuple_equal(tuple, &h->tuple) &&
582 		    nf_ct_zone(ct) == zone) {
583 			NF_CT_STAT_INC(net, found);
584 			rcu_read_unlock_bh();
585 			return 1;
586 		}
587 		NF_CT_STAT_INC(net, searched);
588 	}
589 	rcu_read_unlock_bh();
590 
591 	return 0;
592 }
593 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
594 
595 #define NF_CT_EVICTION_RANGE	8
596 
597 /* There's a small race here where we may free a just-assured
598    connection.  Too bad: we're in trouble anyway. */
early_drop(struct net * net,unsigned int hash)599 static noinline int early_drop(struct net *net, unsigned int hash)
600 {
601 	/* Use oldest entry, which is roughly LRU */
602 	struct nf_conntrack_tuple_hash *h;
603 	struct nf_conn *ct = NULL, *tmp;
604 	struct hlist_nulls_node *n;
605 	unsigned int i, cnt = 0;
606 	int dropped = 0;
607 
608 	rcu_read_lock();
609 	for (i = 0; i < net->ct.htable_size; i++) {
610 		hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
611 					 hnnode) {
612 			tmp = nf_ct_tuplehash_to_ctrack(h);
613 			if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
614 				ct = tmp;
615 			cnt++;
616 		}
617 
618 		if (ct != NULL) {
619 			if (likely(!nf_ct_is_dying(ct) &&
620 				   atomic_inc_not_zero(&ct->ct_general.use)))
621 				break;
622 			else
623 				ct = NULL;
624 		}
625 
626 		if (cnt >= NF_CT_EVICTION_RANGE)
627 			break;
628 
629 		hash = (hash + 1) % net->ct.htable_size;
630 	}
631 	rcu_read_unlock();
632 
633 	if (!ct)
634 		return dropped;
635 
636 	if (del_timer(&ct->timeout)) {
637 		death_by_timeout((unsigned long)ct);
638 		/* Check if we indeed killed this entry. Reliable event
639 		   delivery may have inserted it into the dying list. */
640 		if (test_bit(IPS_DYING_BIT, &ct->status)) {
641 			dropped = 1;
642 			NF_CT_STAT_INC_ATOMIC(net, early_drop);
643 		}
644 	}
645 	nf_ct_put(ct);
646 	return dropped;
647 }
648 
init_nf_conntrack_hash_rnd(void)649 void init_nf_conntrack_hash_rnd(void)
650 {
651 	unsigned int rand;
652 
653 	/*
654 	 * Why not initialize nf_conntrack_rnd in a "init()" function ?
655 	 * Because there isn't enough entropy when system initializing,
656 	 * and we initialize it as late as possible.
657 	 */
658 	do {
659 		get_random_bytes(&rand, sizeof(rand));
660 	} while (!rand);
661 	cmpxchg(&nf_conntrack_hash_rnd, 0, rand);
662 }
663 
664 static struct nf_conn *
__nf_conntrack_alloc(struct net * net,u16 zone,const struct nf_conntrack_tuple * orig,const struct nf_conntrack_tuple * repl,gfp_t gfp,u32 hash)665 __nf_conntrack_alloc(struct net *net, u16 zone,
666 		     const struct nf_conntrack_tuple *orig,
667 		     const struct nf_conntrack_tuple *repl,
668 		     gfp_t gfp, u32 hash)
669 {
670 	struct nf_conn *ct;
671 
672 	if (unlikely(!nf_conntrack_hash_rnd)) {
673 		init_nf_conntrack_hash_rnd();
674 		/* recompute the hash as nf_conntrack_hash_rnd is initialized */
675 		hash = hash_conntrack_raw(orig, zone);
676 	}
677 
678 	/* We don't want any race condition at early drop stage */
679 	atomic_inc(&net->ct.count);
680 
681 	if (nf_conntrack_max &&
682 	    unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
683 		if (!early_drop(net, hash_bucket(hash, net))) {
684 			atomic_dec(&net->ct.count);
685 			if (net_ratelimit())
686 				printk(KERN_WARNING
687 				       "nf_conntrack: table full, dropping"
688 				       " packet.\n");
689 			return ERR_PTR(-ENOMEM);
690 		}
691 	}
692 
693 	/*
694 	 * Do not use kmem_cache_zalloc(), as this cache uses
695 	 * SLAB_DESTROY_BY_RCU.
696 	 */
697 	ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
698 	if (ct == NULL) {
699 		atomic_dec(&net->ct.count);
700 		return ERR_PTR(-ENOMEM);
701 	}
702 	/*
703 	 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
704 	 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
705 	 */
706 	memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
707 	       offsetof(struct nf_conn, proto) -
708 	       offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
709 	spin_lock_init(&ct->lock);
710 	ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
711 	ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
712 	ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
713 	/* save hash for reusing when confirming */
714 	*(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
715 	/* Don't set timer yet: wait for confirmation */
716 	setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
717 	write_pnet(&ct->ct_net, net);
718 #ifdef CONFIG_NF_CONNTRACK_ZONES
719 	if (zone) {
720 		struct nf_conntrack_zone *nf_ct_zone;
721 
722 		nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC);
723 		if (!nf_ct_zone)
724 			goto out_free;
725 		nf_ct_zone->id = zone;
726 	}
727 #endif
728 	/*
729 	 * changes to lookup keys must be done before setting refcnt to 1
730 	 */
731 	smp_wmb();
732 	atomic_set(&ct->ct_general.use, 1);
733 	return ct;
734 
735 #ifdef CONFIG_NF_CONNTRACK_ZONES
736 out_free:
737 	kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
738 	return ERR_PTR(-ENOMEM);
739 #endif
740 }
741 
nf_conntrack_alloc(struct net * net,u16 zone,const struct nf_conntrack_tuple * orig,const struct nf_conntrack_tuple * repl,gfp_t gfp)742 struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
743 				   const struct nf_conntrack_tuple *orig,
744 				   const struct nf_conntrack_tuple *repl,
745 				   gfp_t gfp)
746 {
747 	return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
748 }
749 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
750 
nf_conntrack_free(struct nf_conn * ct)751 void nf_conntrack_free(struct nf_conn *ct)
752 {
753 	struct net *net = nf_ct_net(ct);
754 
755 	nf_ct_ext_destroy(ct);
756 	atomic_dec(&net->ct.count);
757 	nf_ct_ext_free(ct);
758 	kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
759 }
760 EXPORT_SYMBOL_GPL(nf_conntrack_free);
761 
762 /* Allocate a new conntrack: we return -ENOMEM if classification
763    failed due to stress.  Otherwise it really is unclassifiable. */
764 static struct nf_conntrack_tuple_hash *
init_conntrack(struct net * net,struct nf_conn * tmpl,const struct nf_conntrack_tuple * tuple,struct nf_conntrack_l3proto * l3proto,struct nf_conntrack_l4proto * l4proto,struct sk_buff * skb,unsigned int dataoff,u32 hash)765 init_conntrack(struct net *net, struct nf_conn *tmpl,
766 	       const struct nf_conntrack_tuple *tuple,
767 	       struct nf_conntrack_l3proto *l3proto,
768 	       struct nf_conntrack_l4proto *l4proto,
769 	       struct sk_buff *skb,
770 	       unsigned int dataoff, u32 hash)
771 {
772 	struct nf_conn *ct;
773 	struct nf_conn_help *help;
774 	struct nf_conntrack_tuple repl_tuple;
775 	struct nf_conntrack_ecache *ecache;
776 	struct nf_conntrack_expect *exp;
777 	u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
778 
779 	if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
780 		pr_debug("Can't invert tuple.\n");
781 		return NULL;
782 	}
783 
784 	ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
785 				  hash);
786 	if (IS_ERR(ct))
787 		return (struct nf_conntrack_tuple_hash *)ct;
788 
789 	if (!l4proto->new(ct, skb, dataoff)) {
790 		nf_conntrack_free(ct);
791 		pr_debug("init conntrack: can't track with proto module\n");
792 		return NULL;
793 	}
794 
795 	nf_ct_acct_ext_add(ct, GFP_ATOMIC);
796 	nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
797 
798 	ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
799 	nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
800 				 ecache ? ecache->expmask : 0,
801 			     GFP_ATOMIC);
802 
803 	spin_lock_bh(&nf_conntrack_lock);
804 	exp = nf_ct_find_expectation(net, zone, tuple);
805 	if (exp) {
806 		pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
807 			 ct, exp);
808 		/* Welcome, Mr. Bond.  We've been expecting you... */
809 		__set_bit(IPS_EXPECTED_BIT, &ct->status);
810 		ct->master = exp->master;
811 		if (exp->helper) {
812 			help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
813 			if (help)
814 				rcu_assign_pointer(help->helper, exp->helper);
815 		}
816 
817 #ifdef CONFIG_NF_CONNTRACK_MARK
818 		ct->mark = exp->master->mark;
819 #endif
820 #ifdef CONFIG_NF_CONNTRACK_SECMARK
821 		ct->secmark = exp->master->secmark;
822 #endif
823 		nf_conntrack_get(&ct->master->ct_general);
824 		NF_CT_STAT_INC(net, expect_new);
825 	} else {
826 		__nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
827 		NF_CT_STAT_INC(net, new);
828 	}
829 
830 	/* Overload tuple linked list to put us in unconfirmed list. */
831 	hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
832 		       &net->ct.unconfirmed);
833 
834 	spin_unlock_bh(&nf_conntrack_lock);
835 
836 	if (exp) {
837 		if (exp->expectfn)
838 			exp->expectfn(ct, exp);
839 		nf_ct_expect_put(exp);
840 	}
841 
842 	return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
843 }
844 
845 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
846 static inline struct nf_conn *
resolve_normal_ct(struct net * net,struct nf_conn * tmpl,struct sk_buff * skb,unsigned int dataoff,u_int16_t l3num,u_int8_t protonum,struct nf_conntrack_l3proto * l3proto,struct nf_conntrack_l4proto * l4proto,int * set_reply,enum ip_conntrack_info * ctinfo)847 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
848 		  struct sk_buff *skb,
849 		  unsigned int dataoff,
850 		  u_int16_t l3num,
851 		  u_int8_t protonum,
852 		  struct nf_conntrack_l3proto *l3proto,
853 		  struct nf_conntrack_l4proto *l4proto,
854 		  int *set_reply,
855 		  enum ip_conntrack_info *ctinfo)
856 {
857 	struct nf_conntrack_tuple tuple;
858 	struct nf_conntrack_tuple_hash *h;
859 	struct nf_conn *ct;
860 	u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
861 	u32 hash;
862 
863 	if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
864 			     dataoff, l3num, protonum, &tuple, l3proto,
865 			     l4proto)) {
866 		pr_debug("resolve_normal_ct: Can't get tuple\n");
867 		return NULL;
868 	}
869 
870 	/* look for tuple match */
871 	hash = hash_conntrack_raw(&tuple, zone);
872 	h = __nf_conntrack_find_get(net, zone, &tuple, hash);
873 	if (!h) {
874 		h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
875 				   skb, dataoff, hash);
876 		if (!h)
877 			return NULL;
878 		if (IS_ERR(h))
879 			return (void *)h;
880 	}
881 	ct = nf_ct_tuplehash_to_ctrack(h);
882 
883 	/* It exists; we have (non-exclusive) reference. */
884 	if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
885 		*ctinfo = IP_CT_ESTABLISHED_REPLY;
886 		/* Please set reply bit if this packet OK */
887 		*set_reply = 1;
888 	} else {
889 		/* Once we've had two way comms, always ESTABLISHED. */
890 		if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
891 			pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
892 			*ctinfo = IP_CT_ESTABLISHED;
893 		} else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
894 			pr_debug("nf_conntrack_in: related packet for %p\n",
895 				 ct);
896 			*ctinfo = IP_CT_RELATED;
897 		} else {
898 			pr_debug("nf_conntrack_in: new packet for %p\n", ct);
899 			*ctinfo = IP_CT_NEW;
900 		}
901 		*set_reply = 0;
902 	}
903 	skb->nfct = &ct->ct_general;
904 	skb->nfctinfo = *ctinfo;
905 	return ct;
906 }
907 
908 unsigned int
nf_conntrack_in(struct net * net,u_int8_t pf,unsigned int hooknum,struct sk_buff * skb)909 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
910 		struct sk_buff *skb)
911 {
912 	struct nf_conn *ct, *tmpl = NULL;
913 	enum ip_conntrack_info ctinfo;
914 	struct nf_conntrack_l3proto *l3proto;
915 	struct nf_conntrack_l4proto *l4proto;
916 	unsigned int dataoff;
917 	u_int8_t protonum;
918 	int set_reply = 0;
919 	int ret;
920 
921 	if (skb->nfct) {
922 		/* Previously seen (loopback or untracked)?  Ignore. */
923 		tmpl = (struct nf_conn *)skb->nfct;
924 		if (!nf_ct_is_template(tmpl)) {
925 			NF_CT_STAT_INC_ATOMIC(net, ignore);
926 			return NF_ACCEPT;
927 		}
928 		skb->nfct = NULL;
929 	}
930 
931 	/* rcu_read_lock()ed by nf_hook_slow */
932 	l3proto = __nf_ct_l3proto_find(pf);
933 	ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
934 				   &dataoff, &protonum);
935 	if (ret <= 0) {
936 		pr_debug("not prepared to track yet or error occurred\n");
937 		NF_CT_STAT_INC_ATOMIC(net, error);
938 		NF_CT_STAT_INC_ATOMIC(net, invalid);
939 		ret = -ret;
940 		goto out;
941 	}
942 
943 	l4proto = __nf_ct_l4proto_find(pf, protonum);
944 
945 	/* It may be an special packet, error, unclean...
946 	 * inverse of the return code tells to the netfilter
947 	 * core what to do with the packet. */
948 	if (l4proto->error != NULL) {
949 		ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo,
950 				     pf, hooknum);
951 		if (ret <= 0) {
952 			NF_CT_STAT_INC_ATOMIC(net, error);
953 			NF_CT_STAT_INC_ATOMIC(net, invalid);
954 			ret = -ret;
955 			goto out;
956 		}
957 		/* ICMP[v6] protocol trackers may assign one conntrack. */
958 		if (skb->nfct)
959 			goto out;
960 	}
961 
962 	ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
963 			       l3proto, l4proto, &set_reply, &ctinfo);
964 	if (!ct) {
965 		/* Not valid part of a connection */
966 		NF_CT_STAT_INC_ATOMIC(net, invalid);
967 		ret = NF_ACCEPT;
968 		goto out;
969 	}
970 
971 	if (IS_ERR(ct)) {
972 		/* Too stressed to deal. */
973 		NF_CT_STAT_INC_ATOMIC(net, drop);
974 		ret = NF_DROP;
975 		goto out;
976 	}
977 
978 	NF_CT_ASSERT(skb->nfct);
979 
980 	ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
981 	if (ret <= 0) {
982 		/* Invalid: inverse of the return code tells
983 		 * the netfilter core what to do */
984 		pr_debug("nf_conntrack_in: Can't track with proto module\n");
985 		nf_conntrack_put(skb->nfct);
986 		skb->nfct = NULL;
987 		NF_CT_STAT_INC_ATOMIC(net, invalid);
988 		if (ret == -NF_DROP)
989 			NF_CT_STAT_INC_ATOMIC(net, drop);
990 		ret = -ret;
991 		goto out;
992 	}
993 
994 	if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
995 		nf_conntrack_event_cache(IPCT_REPLY, ct);
996 out:
997 	if (tmpl) {
998 		/* Special case: we have to repeat this hook, assign the
999 		 * template again to this packet. We assume that this packet
1000 		 * has no conntrack assigned. This is used by nf_ct_tcp. */
1001 		if (ret == NF_REPEAT)
1002 			skb->nfct = (struct nf_conntrack *)tmpl;
1003 		else
1004 			nf_ct_put(tmpl);
1005 	}
1006 
1007 	return ret;
1008 }
1009 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1010 
nf_ct_invert_tuplepr(struct nf_conntrack_tuple * inverse,const struct nf_conntrack_tuple * orig)1011 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
1012 			  const struct nf_conntrack_tuple *orig)
1013 {
1014 	bool ret;
1015 
1016 	rcu_read_lock();
1017 	ret = nf_ct_invert_tuple(inverse, orig,
1018 				 __nf_ct_l3proto_find(orig->src.l3num),
1019 				 __nf_ct_l4proto_find(orig->src.l3num,
1020 						      orig->dst.protonum));
1021 	rcu_read_unlock();
1022 	return ret;
1023 }
1024 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
1025 
1026 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1027    implicitly racy: see __nf_conntrack_confirm */
nf_conntrack_alter_reply(struct nf_conn * ct,const struct nf_conntrack_tuple * newreply)1028 void nf_conntrack_alter_reply(struct nf_conn *ct,
1029 			      const struct nf_conntrack_tuple *newreply)
1030 {
1031 	struct nf_conn_help *help = nfct_help(ct);
1032 
1033 	/* Should be unconfirmed, so not in hash table yet */
1034 	NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
1035 
1036 	pr_debug("Altering reply tuple of %p to ", ct);
1037 	nf_ct_dump_tuple(newreply);
1038 
1039 	ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1040 	if (ct->master || (help && !hlist_empty(&help->expectations)))
1041 		return;
1042 
1043 	rcu_read_lock();
1044 	__nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1045 	rcu_read_unlock();
1046 }
1047 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1048 
1049 /* 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,unsigned long extra_jiffies,int do_acct)1050 void __nf_ct_refresh_acct(struct nf_conn *ct,
1051 			  enum ip_conntrack_info ctinfo,
1052 			  const struct sk_buff *skb,
1053 			  unsigned long extra_jiffies,
1054 			  int do_acct)
1055 {
1056 	NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
1057 	NF_CT_ASSERT(skb);
1058 
1059 	/* Only update if this is not a fixed timeout */
1060 	if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1061 		goto acct;
1062 
1063 	/* If not in hash table, timer will not be active yet */
1064 	if (!nf_ct_is_confirmed(ct)) {
1065 		ct->timeout.expires = extra_jiffies;
1066 	} else {
1067 		unsigned long newtime = jiffies + extra_jiffies;
1068 
1069 		/* Only update the timeout if the new timeout is at least
1070 		   HZ jiffies from the old timeout. Need del_timer for race
1071 		   avoidance (may already be dying). */
1072 		if (newtime - ct->timeout.expires >= HZ)
1073 			mod_timer_pending(&ct->timeout, newtime);
1074 	}
1075 
1076 acct:
1077 	if (do_acct) {
1078 		struct nf_conn_counter *acct;
1079 
1080 		acct = nf_conn_acct_find(ct);
1081 		if (acct) {
1082 			atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets);
1083 			atomic64_add(skb->len, &acct[CTINFO2DIR(ctinfo)].bytes);
1084 		}
1085 	}
1086 }
1087 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1088 
__nf_ct_kill_acct(struct nf_conn * ct,enum ip_conntrack_info ctinfo,const struct sk_buff * skb,int do_acct)1089 bool __nf_ct_kill_acct(struct nf_conn *ct,
1090 		       enum ip_conntrack_info ctinfo,
1091 		       const struct sk_buff *skb,
1092 		       int do_acct)
1093 {
1094 	if (do_acct) {
1095 		struct nf_conn_counter *acct;
1096 
1097 		acct = nf_conn_acct_find(ct);
1098 		if (acct) {
1099 			atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets);
1100 			atomic64_add(skb->len - skb_network_offset(skb),
1101 				     &acct[CTINFO2DIR(ctinfo)].bytes);
1102 		}
1103 	}
1104 
1105 	if (del_timer(&ct->timeout)) {
1106 		ct->timeout.function((unsigned long)ct);
1107 		return true;
1108 	}
1109 	return false;
1110 }
1111 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
1112 
1113 #ifdef CONFIG_NF_CONNTRACK_ZONES
1114 static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = {
1115 	.len	= sizeof(struct nf_conntrack_zone),
1116 	.align	= __alignof__(struct nf_conntrack_zone),
1117 	.id	= NF_CT_EXT_ZONE,
1118 };
1119 #endif
1120 
1121 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1122 
1123 #include <linux/netfilter/nfnetlink.h>
1124 #include <linux/netfilter/nfnetlink_conntrack.h>
1125 #include <linux/mutex.h>
1126 
1127 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
1128  * in ip_conntrack_core, since we don't want the protocols to autoload
1129  * or depend on ctnetlink */
nf_ct_port_tuple_to_nlattr(struct sk_buff * skb,const struct nf_conntrack_tuple * tuple)1130 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1131 			       const struct nf_conntrack_tuple *tuple)
1132 {
1133 	NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
1134 	NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
1135 	return 0;
1136 
1137 nla_put_failure:
1138 	return -1;
1139 }
1140 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1141 
1142 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1143 	[CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1144 	[CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1145 };
1146 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1147 
nf_ct_port_nlattr_to_tuple(struct nlattr * tb[],struct nf_conntrack_tuple * t)1148 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1149 			       struct nf_conntrack_tuple *t)
1150 {
1151 	if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1152 		return -EINVAL;
1153 
1154 	t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1155 	t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1156 
1157 	return 0;
1158 }
1159 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1160 
nf_ct_port_nlattr_tuple_size(void)1161 int nf_ct_port_nlattr_tuple_size(void)
1162 {
1163 	return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1164 }
1165 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1166 #endif
1167 
1168 /* Used by ipt_REJECT and ip6t_REJECT. */
nf_conntrack_attach(struct sk_buff * nskb,struct sk_buff * skb)1169 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1170 {
1171 	struct nf_conn *ct;
1172 	enum ip_conntrack_info ctinfo;
1173 
1174 	/* This ICMP is in reverse direction to the packet which caused it */
1175 	ct = nf_ct_get(skb, &ctinfo);
1176 	if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1177 		ctinfo = IP_CT_RELATED_REPLY;
1178 	else
1179 		ctinfo = IP_CT_RELATED;
1180 
1181 	/* Attach to new skbuff, and increment count */
1182 	nskb->nfct = &ct->ct_general;
1183 	nskb->nfctinfo = ctinfo;
1184 	nf_conntrack_get(nskb->nfct);
1185 }
1186 
1187 /* Bring out ya dead! */
1188 static struct nf_conn *
get_next_corpse(struct net * net,int (* iter)(struct nf_conn * i,void * data),void * data,unsigned int * bucket)1189 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1190 		void *data, unsigned int *bucket)
1191 {
1192 	struct nf_conntrack_tuple_hash *h;
1193 	struct nf_conn *ct;
1194 	struct hlist_nulls_node *n;
1195 
1196 	spin_lock_bh(&nf_conntrack_lock);
1197 	for (; *bucket < net->ct.htable_size; (*bucket)++) {
1198 		hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1199 			ct = nf_ct_tuplehash_to_ctrack(h);
1200 			if (iter(ct, data))
1201 				goto found;
1202 		}
1203 	}
1204 	hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1205 		ct = nf_ct_tuplehash_to_ctrack(h);
1206 		if (iter(ct, data))
1207 			set_bit(IPS_DYING_BIT, &ct->status);
1208 	}
1209 	spin_unlock_bh(&nf_conntrack_lock);
1210 	return NULL;
1211 found:
1212 	atomic_inc(&ct->ct_general.use);
1213 	spin_unlock_bh(&nf_conntrack_lock);
1214 	return ct;
1215 }
1216 
nf_ct_iterate_cleanup(struct net * net,int (* iter)(struct nf_conn * i,void * data),void * data)1217 void nf_ct_iterate_cleanup(struct net *net,
1218 			   int (*iter)(struct nf_conn *i, void *data),
1219 			   void *data)
1220 {
1221 	struct nf_conn *ct;
1222 	unsigned int bucket = 0;
1223 
1224 	while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1225 		/* Time to push up daises... */
1226 		if (del_timer(&ct->timeout))
1227 			death_by_timeout((unsigned long)ct);
1228 		/* ... else the timer will get him soon. */
1229 
1230 		nf_ct_put(ct);
1231 	}
1232 }
1233 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1234 
1235 struct __nf_ct_flush_report {
1236 	u32 pid;
1237 	int report;
1238 };
1239 
kill_report(struct nf_conn * i,void * data)1240 static int kill_report(struct nf_conn *i, void *data)
1241 {
1242 	struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1243 	struct nf_conn_tstamp *tstamp;
1244 
1245 	tstamp = nf_conn_tstamp_find(i);
1246 	if (tstamp && tstamp->stop == 0)
1247 		tstamp->stop = ktime_to_ns(ktime_get_real());
1248 
1249 	/* If we fail to deliver the event, death_by_timeout() will retry */
1250 	if (nf_conntrack_event_report(IPCT_DESTROY, i,
1251 				      fr->pid, fr->report) < 0)
1252 		return 1;
1253 
1254 	/* Avoid the delivery of the destroy event in death_by_timeout(). */
1255 	set_bit(IPS_DYING_BIT, &i->status);
1256 	return 1;
1257 }
1258 
kill_all(struct nf_conn * i,void * data)1259 static int kill_all(struct nf_conn *i, void *data)
1260 {
1261 	return 1;
1262 }
1263 
nf_ct_free_hashtable(void * hash,unsigned int size)1264 void nf_ct_free_hashtable(void *hash, unsigned int size)
1265 {
1266 	if (is_vmalloc_addr(hash))
1267 		vfree(hash);
1268 	else
1269 		free_pages((unsigned long)hash,
1270 			   get_order(sizeof(struct hlist_head) * size));
1271 }
1272 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1273 
nf_conntrack_flush_report(struct net * net,u32 pid,int report)1274 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1275 {
1276 	struct __nf_ct_flush_report fr = {
1277 		.pid 	= pid,
1278 		.report = report,
1279 	};
1280 	nf_ct_iterate_cleanup(net, kill_report, &fr);
1281 }
1282 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1283 
nf_ct_release_dying_list(struct net * net)1284 static void nf_ct_release_dying_list(struct net *net)
1285 {
1286 	struct nf_conntrack_tuple_hash *h;
1287 	struct nf_conn *ct;
1288 	struct hlist_nulls_node *n;
1289 
1290 	spin_lock_bh(&nf_conntrack_lock);
1291 	hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) {
1292 		ct = nf_ct_tuplehash_to_ctrack(h);
1293 		/* never fails to remove them, no listeners at this point */
1294 		nf_ct_kill(ct);
1295 	}
1296 	spin_unlock_bh(&nf_conntrack_lock);
1297 }
1298 
untrack_refs(void)1299 static int untrack_refs(void)
1300 {
1301 	int cnt = 0, cpu;
1302 
1303 	for_each_possible_cpu(cpu) {
1304 		struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1305 
1306 		cnt += atomic_read(&ct->ct_general.use) - 1;
1307 	}
1308 	return cnt;
1309 }
1310 
nf_conntrack_cleanup_init_net(void)1311 static void nf_conntrack_cleanup_init_net(void)
1312 {
1313 	while (untrack_refs() > 0)
1314 		schedule();
1315 
1316 	nf_conntrack_helper_fini();
1317 	nf_conntrack_proto_fini();
1318 #ifdef CONFIG_NF_CONNTRACK_ZONES
1319 	nf_ct_extend_unregister(&nf_ct_zone_extend);
1320 #endif
1321 }
1322 
nf_conntrack_cleanup_net(struct net * net)1323 static void nf_conntrack_cleanup_net(struct net *net)
1324 {
1325  i_see_dead_people:
1326 	nf_ct_iterate_cleanup(net, kill_all, NULL);
1327 	nf_ct_release_dying_list(net);
1328 	if (atomic_read(&net->ct.count) != 0) {
1329 		schedule();
1330 		goto i_see_dead_people;
1331 	}
1332 
1333 	nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1334 	nf_conntrack_ecache_fini(net);
1335 	nf_conntrack_tstamp_fini(net);
1336 	nf_conntrack_acct_fini(net);
1337 	nf_conntrack_expect_fini(net);
1338 	kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1339 	kfree(net->ct.slabname);
1340 	free_percpu(net->ct.stat);
1341 }
1342 
1343 /* Mishearing the voices in his head, our hero wonders how he's
1344    supposed to kill the mall. */
nf_conntrack_cleanup(struct net * net)1345 void nf_conntrack_cleanup(struct net *net)
1346 {
1347 	if (net_eq(net, &init_net))
1348 		RCU_INIT_POINTER(ip_ct_attach, NULL);
1349 
1350 	/* This makes sure all current packets have passed through
1351 	   netfilter framework.  Roll on, two-stage module
1352 	   delete... */
1353 	synchronize_net();
1354 
1355 	nf_conntrack_cleanup_net(net);
1356 
1357 	if (net_eq(net, &init_net)) {
1358 		RCU_INIT_POINTER(nf_ct_destroy, NULL);
1359 		nf_conntrack_cleanup_init_net();
1360 	}
1361 }
1362 
nf_ct_alloc_hashtable(unsigned int * sizep,int nulls)1363 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
1364 {
1365 	struct hlist_nulls_head *hash;
1366 	unsigned int nr_slots, i;
1367 	size_t sz;
1368 
1369 	BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1370 	nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1371 	sz = nr_slots * sizeof(struct hlist_nulls_head);
1372 	hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1373 					get_order(sz));
1374 	if (!hash) {
1375 		printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1376 		hash = vzalloc(sz);
1377 	}
1378 
1379 	if (hash && nulls)
1380 		for (i = 0; i < nr_slots; i++)
1381 			INIT_HLIST_NULLS_HEAD(&hash[i], i);
1382 
1383 	return hash;
1384 }
1385 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1386 
nf_conntrack_set_hashsize(const char * val,struct kernel_param * kp)1387 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1388 {
1389 	int i, bucket;
1390 	unsigned int hashsize, old_size;
1391 	struct hlist_nulls_head *hash, *old_hash;
1392 	struct nf_conntrack_tuple_hash *h;
1393 	struct nf_conn *ct;
1394 
1395 	if (current->nsproxy->net_ns != &init_net)
1396 		return -EOPNOTSUPP;
1397 
1398 	/* On boot, we can set this without any fancy locking. */
1399 	if (!nf_conntrack_htable_size)
1400 		return param_set_uint(val, kp);
1401 
1402 	hashsize = simple_strtoul(val, NULL, 0);
1403 	if (!hashsize)
1404 		return -EINVAL;
1405 
1406 	hash = nf_ct_alloc_hashtable(&hashsize, 1);
1407 	if (!hash)
1408 		return -ENOMEM;
1409 
1410 	/* Lookups in the old hash might happen in parallel, which means we
1411 	 * might get false negatives during connection lookup. New connections
1412 	 * created because of a false negative won't make it into the hash
1413 	 * though since that required taking the lock.
1414 	 */
1415 	spin_lock_bh(&nf_conntrack_lock);
1416 	for (i = 0; i < init_net.ct.htable_size; i++) {
1417 		while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1418 			h = hlist_nulls_entry(init_net.ct.hash[i].first,
1419 					struct nf_conntrack_tuple_hash, hnnode);
1420 			ct = nf_ct_tuplehash_to_ctrack(h);
1421 			hlist_nulls_del_rcu(&h->hnnode);
1422 			bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct),
1423 						  hashsize);
1424 			hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1425 		}
1426 	}
1427 	old_size = init_net.ct.htable_size;
1428 	old_hash = init_net.ct.hash;
1429 
1430 	init_net.ct.htable_size = nf_conntrack_htable_size = hashsize;
1431 	init_net.ct.hash = hash;
1432 	spin_unlock_bh(&nf_conntrack_lock);
1433 
1434 	nf_ct_free_hashtable(old_hash, old_size);
1435 	return 0;
1436 }
1437 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1438 
1439 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1440 		  &nf_conntrack_htable_size, 0600);
1441 
nf_ct_untracked_status_or(unsigned long bits)1442 void nf_ct_untracked_status_or(unsigned long bits)
1443 {
1444 	int cpu;
1445 
1446 	for_each_possible_cpu(cpu)
1447 		per_cpu(nf_conntrack_untracked, cpu).status |= bits;
1448 }
1449 EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or);
1450 
nf_conntrack_init_init_net(void)1451 static int nf_conntrack_init_init_net(void)
1452 {
1453 	int max_factor = 8;
1454 	int ret, cpu;
1455 
1456 	/* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1457 	 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1458 	if (!nf_conntrack_htable_size) {
1459 		nf_conntrack_htable_size
1460 			= (((totalram_pages << PAGE_SHIFT) / 16384)
1461 			   / sizeof(struct hlist_head));
1462 		if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1463 			nf_conntrack_htable_size = 16384;
1464 		if (nf_conntrack_htable_size < 32)
1465 			nf_conntrack_htable_size = 32;
1466 
1467 		/* Use a max. factor of four by default to get the same max as
1468 		 * with the old struct list_heads. When a table size is given
1469 		 * we use the old value of 8 to avoid reducing the max.
1470 		 * entries. */
1471 		max_factor = 4;
1472 	}
1473 	nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1474 
1475 	printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
1476 	       NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1477 	       nf_conntrack_max);
1478 
1479 	ret = nf_conntrack_proto_init();
1480 	if (ret < 0)
1481 		goto err_proto;
1482 
1483 	ret = nf_conntrack_helper_init();
1484 	if (ret < 0)
1485 		goto err_helper;
1486 
1487 #ifdef CONFIG_NF_CONNTRACK_ZONES
1488 	ret = nf_ct_extend_register(&nf_ct_zone_extend);
1489 	if (ret < 0)
1490 		goto err_extend;
1491 #endif
1492 	/* Set up fake conntrack: to never be deleted, not in any hashes */
1493 	for_each_possible_cpu(cpu) {
1494 		struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1495 		write_pnet(&ct->ct_net, &init_net);
1496 		atomic_set(&ct->ct_general.use, 1);
1497 	}
1498 	/*  - and look it like as a confirmed connection */
1499 	nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED);
1500 	return 0;
1501 
1502 #ifdef CONFIG_NF_CONNTRACK_ZONES
1503 err_extend:
1504 	nf_conntrack_helper_fini();
1505 #endif
1506 err_helper:
1507 	nf_conntrack_proto_fini();
1508 err_proto:
1509 	return ret;
1510 }
1511 
1512 /*
1513  * We need to use special "null" values, not used in hash table
1514  */
1515 #define UNCONFIRMED_NULLS_VAL	((1<<30)+0)
1516 #define DYING_NULLS_VAL		((1<<30)+1)
1517 
nf_conntrack_init_net(struct net * net)1518 static int nf_conntrack_init_net(struct net *net)
1519 {
1520 	int ret;
1521 
1522 	atomic_set(&net->ct.count, 0);
1523 	INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1524 	INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1525 	net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1526 	if (!net->ct.stat) {
1527 		ret = -ENOMEM;
1528 		goto err_stat;
1529 	}
1530 
1531 	net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1532 	if (!net->ct.slabname) {
1533 		ret = -ENOMEM;
1534 		goto err_slabname;
1535 	}
1536 
1537 	net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1538 							sizeof(struct nf_conn), 0,
1539 							SLAB_DESTROY_BY_RCU, NULL);
1540 	if (!net->ct.nf_conntrack_cachep) {
1541 		printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1542 		ret = -ENOMEM;
1543 		goto err_cache;
1544 	}
1545 
1546 	net->ct.htable_size = nf_conntrack_htable_size;
1547 	net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1);
1548 	if (!net->ct.hash) {
1549 		ret = -ENOMEM;
1550 		printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1551 		goto err_hash;
1552 	}
1553 	ret = nf_conntrack_expect_init(net);
1554 	if (ret < 0)
1555 		goto err_expect;
1556 	ret = nf_conntrack_acct_init(net);
1557 	if (ret < 0)
1558 		goto err_acct;
1559 	ret = nf_conntrack_tstamp_init(net);
1560 	if (ret < 0)
1561 		goto err_tstamp;
1562 	ret = nf_conntrack_ecache_init(net);
1563 	if (ret < 0)
1564 		goto err_ecache;
1565 
1566 	return 0;
1567 
1568 err_ecache:
1569 	nf_conntrack_tstamp_fini(net);
1570 err_tstamp:
1571 	nf_conntrack_acct_fini(net);
1572 err_acct:
1573 	nf_conntrack_expect_fini(net);
1574 err_expect:
1575 	nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1576 err_hash:
1577 	kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1578 err_cache:
1579 	kfree(net->ct.slabname);
1580 err_slabname:
1581 	free_percpu(net->ct.stat);
1582 err_stat:
1583 	return ret;
1584 }
1585 
1586 s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
1587 			enum ip_conntrack_dir dir,
1588 			u32 seq);
1589 EXPORT_SYMBOL_GPL(nf_ct_nat_offset);
1590 
nf_conntrack_init(struct net * net)1591 int nf_conntrack_init(struct net *net)
1592 {
1593 	int ret;
1594 
1595 	if (net_eq(net, &init_net)) {
1596 		ret = nf_conntrack_init_init_net();
1597 		if (ret < 0)
1598 			goto out_init_net;
1599 	}
1600 	ret = nf_conntrack_init_net(net);
1601 	if (ret < 0)
1602 		goto out_net;
1603 
1604 	if (net_eq(net, &init_net)) {
1605 		/* For use by REJECT target */
1606 		RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
1607 		RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
1608 
1609 		/* Howto get NAT offsets */
1610 		RCU_INIT_POINTER(nf_ct_nat_offset, NULL);
1611 	}
1612 	return 0;
1613 
1614 out_net:
1615 	if (net_eq(net, &init_net))
1616 		nf_conntrack_cleanup_init_net();
1617 out_init_net:
1618 	return ret;
1619 }
1620