netfilter: nf_conntrack: per netns nf_conntrack_cachep
[linux-2.6.git] / net / netfilter / nf_conntrack_core.c
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/rculist_nulls.h>
34
35 #include <net/netfilter/nf_conntrack.h>
36 #include <net/netfilter/nf_conntrack_l3proto.h>
37 #include <net/netfilter/nf_conntrack_l4proto.h>
38 #include <net/netfilter/nf_conntrack_expect.h>
39 #include <net/netfilter/nf_conntrack_helper.h>
40 #include <net/netfilter/nf_conntrack_core.h>
41 #include <net/netfilter/nf_conntrack_extend.h>
42 #include <net/netfilter/nf_conntrack_acct.h>
43 #include <net/netfilter/nf_conntrack_ecache.h>
44 #include <net/netfilter/nf_nat.h>
45 #include <net/netfilter/nf_nat_core.h>
46
47 #define NF_CONNTRACK_VERSION    "0.5.0"
48
49 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
50                                       enum nf_nat_manip_type manip,
51                                       const struct nlattr *attr) __read_mostly;
52 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
53
54 DEFINE_SPINLOCK(nf_conntrack_lock);
55 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
56
57 unsigned int nf_conntrack_htable_size __read_mostly;
58 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
59
60 unsigned int nf_conntrack_max __read_mostly;
61 EXPORT_SYMBOL_GPL(nf_conntrack_max);
62
63 struct nf_conn nf_conntrack_untracked __read_mostly;
64 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
65
66 static int nf_conntrack_hash_rnd_initted;
67 static unsigned int nf_conntrack_hash_rnd;
68
69 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
70                                   unsigned int size, unsigned int rnd)
71 {
72         unsigned int n;
73         u_int32_t h;
74
75         /* The direction must be ignored, so we hash everything up to the
76          * destination ports (which is a multiple of 4) and treat the last
77          * three bytes manually.
78          */
79         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
80         h = jhash2((u32 *)tuple, n,
81                    rnd ^ (((__force __u16)tuple->dst.u.all << 16) |
82                           tuple->dst.protonum));
83
84         return ((u64)h * size) >> 32;
85 }
86
87 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
88 {
89         return __hash_conntrack(tuple, nf_conntrack_htable_size,
90                                 nf_conntrack_hash_rnd);
91 }
92
93 bool
94 nf_ct_get_tuple(const struct sk_buff *skb,
95                 unsigned int nhoff,
96                 unsigned int dataoff,
97                 u_int16_t l3num,
98                 u_int8_t protonum,
99                 struct nf_conntrack_tuple *tuple,
100                 const struct nf_conntrack_l3proto *l3proto,
101                 const struct nf_conntrack_l4proto *l4proto)
102 {
103         memset(tuple, 0, sizeof(*tuple));
104
105         tuple->src.l3num = l3num;
106         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
107                 return false;
108
109         tuple->dst.protonum = protonum;
110         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
111
112         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
113 }
114 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
115
116 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
117                        u_int16_t l3num, struct nf_conntrack_tuple *tuple)
118 {
119         struct nf_conntrack_l3proto *l3proto;
120         struct nf_conntrack_l4proto *l4proto;
121         unsigned int protoff;
122         u_int8_t protonum;
123         int ret;
124
125         rcu_read_lock();
126
127         l3proto = __nf_ct_l3proto_find(l3num);
128         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
129         if (ret != NF_ACCEPT) {
130                 rcu_read_unlock();
131                 return false;
132         }
133
134         l4proto = __nf_ct_l4proto_find(l3num, protonum);
135
136         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
137                               l3proto, l4proto);
138
139         rcu_read_unlock();
140         return ret;
141 }
142 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
143
144 bool
145 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
146                    const struct nf_conntrack_tuple *orig,
147                    const struct nf_conntrack_l3proto *l3proto,
148                    const struct nf_conntrack_l4proto *l4proto)
149 {
150         memset(inverse, 0, sizeof(*inverse));
151
152         inverse->src.l3num = orig->src.l3num;
153         if (l3proto->invert_tuple(inverse, orig) == 0)
154                 return false;
155
156         inverse->dst.dir = !orig->dst.dir;
157
158         inverse->dst.protonum = orig->dst.protonum;
159         return l4proto->invert_tuple(inverse, orig);
160 }
161 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
162
163 static void
164 clean_from_lists(struct nf_conn *ct)
165 {
166         pr_debug("clean_from_lists(%p)\n", ct);
167         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
168         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
169
170         /* Destroy all pending expectations */
171         nf_ct_remove_expectations(ct);
172 }
173
174 static void
175 destroy_conntrack(struct nf_conntrack *nfct)
176 {
177         struct nf_conn *ct = (struct nf_conn *)nfct;
178         struct net *net = nf_ct_net(ct);
179         struct nf_conntrack_l4proto *l4proto;
180
181         pr_debug("destroy_conntrack(%p)\n", ct);
182         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
183         NF_CT_ASSERT(!timer_pending(&ct->timeout));
184
185         /* To make sure we don't get any weird locking issues here:
186          * destroy_conntrack() MUST NOT be called with a write lock
187          * to nf_conntrack_lock!!! -HW */
188         rcu_read_lock();
189         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
190         if (l4proto && l4proto->destroy)
191                 l4proto->destroy(ct);
192
193         rcu_read_unlock();
194
195         spin_lock_bh(&nf_conntrack_lock);
196         /* Expectations will have been removed in clean_from_lists,
197          * except TFTP can create an expectation on the first packet,
198          * before connection is in the list, so we need to clean here,
199          * too. */
200         nf_ct_remove_expectations(ct);
201
202         /* We overload first tuple to link into unconfirmed list. */
203         if (!nf_ct_is_confirmed(ct)) {
204                 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
205                 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
206         }
207
208         NF_CT_STAT_INC(net, delete);
209         spin_unlock_bh(&nf_conntrack_lock);
210
211         if (ct->master)
212                 nf_ct_put(ct->master);
213
214         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
215         nf_conntrack_free(ct);
216 }
217
218 void nf_ct_delete_from_lists(struct nf_conn *ct)
219 {
220         struct net *net = nf_ct_net(ct);
221
222         nf_ct_helper_destroy(ct);
223         spin_lock_bh(&nf_conntrack_lock);
224         /* Inside lock so preempt is disabled on module removal path.
225          * Otherwise we can get spurious warnings. */
226         NF_CT_STAT_INC(net, delete_list);
227         clean_from_lists(ct);
228         spin_unlock_bh(&nf_conntrack_lock);
229 }
230 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
231
232 static void death_by_event(unsigned long ul_conntrack)
233 {
234         struct nf_conn *ct = (void *)ul_conntrack;
235         struct net *net = nf_ct_net(ct);
236
237         if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
238                 /* bad luck, let's retry again */
239                 ct->timeout.expires = jiffies +
240                         (random32() % net->ct.sysctl_events_retry_timeout);
241                 add_timer(&ct->timeout);
242                 return;
243         }
244         /* we've got the event delivered, now it's dying */
245         set_bit(IPS_DYING_BIT, &ct->status);
246         spin_lock(&nf_conntrack_lock);
247         hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
248         spin_unlock(&nf_conntrack_lock);
249         nf_ct_put(ct);
250 }
251
252 void nf_ct_insert_dying_list(struct nf_conn *ct)
253 {
254         struct net *net = nf_ct_net(ct);
255
256         /* add this conntrack to the dying list */
257         spin_lock_bh(&nf_conntrack_lock);
258         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
259                              &net->ct.dying);
260         spin_unlock_bh(&nf_conntrack_lock);
261         /* set a new timer to retry event delivery */
262         setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
263         ct->timeout.expires = jiffies +
264                 (random32() % net->ct.sysctl_events_retry_timeout);
265         add_timer(&ct->timeout);
266 }
267 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
268
269 static void death_by_timeout(unsigned long ul_conntrack)
270 {
271         struct nf_conn *ct = (void *)ul_conntrack;
272
273         if (!test_bit(IPS_DYING_BIT, &ct->status) &&
274             unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
275                 /* destroy event was not delivered */
276                 nf_ct_delete_from_lists(ct);
277                 nf_ct_insert_dying_list(ct);
278                 return;
279         }
280         set_bit(IPS_DYING_BIT, &ct->status);
281         nf_ct_delete_from_lists(ct);
282         nf_ct_put(ct);
283 }
284
285 /*
286  * Warning :
287  * - Caller must take a reference on returned object
288  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
289  * OR
290  * - Caller must lock nf_conntrack_lock before calling this function
291  */
292 struct nf_conntrack_tuple_hash *
293 __nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple)
294 {
295         struct nf_conntrack_tuple_hash *h;
296         struct hlist_nulls_node *n;
297         unsigned int hash = hash_conntrack(tuple);
298
299         /* Disable BHs the entire time since we normally need to disable them
300          * at least once for the stats anyway.
301          */
302         local_bh_disable();
303 begin:
304         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
305                 if (nf_ct_tuple_equal(tuple, &h->tuple)) {
306                         NF_CT_STAT_INC(net, found);
307                         local_bh_enable();
308                         return h;
309                 }
310                 NF_CT_STAT_INC(net, searched);
311         }
312         /*
313          * if the nulls value we got at the end of this lookup is
314          * not the expected one, we must restart lookup.
315          * We probably met an item that was moved to another chain.
316          */
317         if (get_nulls_value(n) != hash)
318                 goto begin;
319         local_bh_enable();
320
321         return NULL;
322 }
323 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
324
325 /* Find a connection corresponding to a tuple. */
326 struct nf_conntrack_tuple_hash *
327 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple)
328 {
329         struct nf_conntrack_tuple_hash *h;
330         struct nf_conn *ct;
331
332         rcu_read_lock();
333 begin:
334         h = __nf_conntrack_find(net, tuple);
335         if (h) {
336                 ct = nf_ct_tuplehash_to_ctrack(h);
337                 if (unlikely(nf_ct_is_dying(ct) ||
338                              !atomic_inc_not_zero(&ct->ct_general.use)))
339                         h = NULL;
340                 else {
341                         if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) {
342                                 nf_ct_put(ct);
343                                 goto begin;
344                         }
345                 }
346         }
347         rcu_read_unlock();
348
349         return h;
350 }
351 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
352
353 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
354                                        unsigned int hash,
355                                        unsigned int repl_hash)
356 {
357         struct net *net = nf_ct_net(ct);
358
359         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
360                            &net->ct.hash[hash]);
361         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
362                            &net->ct.hash[repl_hash]);
363 }
364
365 void nf_conntrack_hash_insert(struct nf_conn *ct)
366 {
367         unsigned int hash, repl_hash;
368
369         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
370         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
371
372         __nf_conntrack_hash_insert(ct, hash, repl_hash);
373 }
374 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
375
376 /* Confirm a connection given skb; places it in hash table */
377 int
378 __nf_conntrack_confirm(struct sk_buff *skb)
379 {
380         unsigned int hash, repl_hash;
381         struct nf_conntrack_tuple_hash *h;
382         struct nf_conn *ct;
383         struct nf_conn_help *help;
384         struct hlist_nulls_node *n;
385         enum ip_conntrack_info ctinfo;
386         struct net *net;
387
388         ct = nf_ct_get(skb, &ctinfo);
389         net = nf_ct_net(ct);
390
391         /* ipt_REJECT uses nf_conntrack_attach to attach related
392            ICMP/TCP RST packets in other direction.  Actual packet
393            which created connection will be IP_CT_NEW or for an
394            expected connection, IP_CT_RELATED. */
395         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
396                 return NF_ACCEPT;
397
398         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
399         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
400
401         /* We're not in hash table, and we refuse to set up related
402            connections for unconfirmed conns.  But packet copies and
403            REJECT will give spurious warnings here. */
404         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
405
406         /* No external references means noone else could have
407            confirmed us. */
408         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
409         pr_debug("Confirming conntrack %p\n", ct);
410
411         spin_lock_bh(&nf_conntrack_lock);
412
413         /* See if there's one in the list already, including reverse:
414            NAT could have grabbed it without realizing, since we're
415            not in the hash.  If there is, we lost race. */
416         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
417                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
418                                       &h->tuple))
419                         goto out;
420         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
421                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
422                                       &h->tuple))
423                         goto out;
424
425         /* Remove from unconfirmed list */
426         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
427
428         /* Timer relative to confirmation time, not original
429            setting time, otherwise we'd get timer wrap in
430            weird delay cases. */
431         ct->timeout.expires += jiffies;
432         add_timer(&ct->timeout);
433         atomic_inc(&ct->ct_general.use);
434         set_bit(IPS_CONFIRMED_BIT, &ct->status);
435
436         /* Since the lookup is lockless, hash insertion must be done after
437          * starting the timer and setting the CONFIRMED bit. The RCU barriers
438          * guarantee that no other CPU can find the conntrack before the above
439          * stores are visible.
440          */
441         __nf_conntrack_hash_insert(ct, hash, repl_hash);
442         NF_CT_STAT_INC(net, insert);
443         spin_unlock_bh(&nf_conntrack_lock);
444
445         help = nfct_help(ct);
446         if (help && help->helper)
447                 nf_conntrack_event_cache(IPCT_HELPER, ct);
448
449         nf_conntrack_event_cache(master_ct(ct) ?
450                                  IPCT_RELATED : IPCT_NEW, ct);
451         return NF_ACCEPT;
452
453 out:
454         NF_CT_STAT_INC(net, insert_failed);
455         spin_unlock_bh(&nf_conntrack_lock);
456         return NF_DROP;
457 }
458 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
459
460 /* Returns true if a connection correspondings to the tuple (required
461    for NAT). */
462 int
463 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
464                          const struct nf_conn *ignored_conntrack)
465 {
466         struct net *net = nf_ct_net(ignored_conntrack);
467         struct nf_conntrack_tuple_hash *h;
468         struct hlist_nulls_node *n;
469         unsigned int hash = hash_conntrack(tuple);
470
471         /* Disable BHs the entire time since we need to disable them at
472          * least once for the stats anyway.
473          */
474         rcu_read_lock_bh();
475         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
476                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
477                     nf_ct_tuple_equal(tuple, &h->tuple)) {
478                         NF_CT_STAT_INC(net, found);
479                         rcu_read_unlock_bh();
480                         return 1;
481                 }
482                 NF_CT_STAT_INC(net, searched);
483         }
484         rcu_read_unlock_bh();
485
486         return 0;
487 }
488 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
489
490 #define NF_CT_EVICTION_RANGE    8
491
492 /* There's a small race here where we may free a just-assured
493    connection.  Too bad: we're in trouble anyway. */
494 static noinline int early_drop(struct net *net, unsigned int hash)
495 {
496         /* Use oldest entry, which is roughly LRU */
497         struct nf_conntrack_tuple_hash *h;
498         struct nf_conn *ct = NULL, *tmp;
499         struct hlist_nulls_node *n;
500         unsigned int i, cnt = 0;
501         int dropped = 0;
502
503         rcu_read_lock();
504         for (i = 0; i < nf_conntrack_htable_size; i++) {
505                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
506                                          hnnode) {
507                         tmp = nf_ct_tuplehash_to_ctrack(h);
508                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
509                                 ct = tmp;
510                         cnt++;
511                 }
512
513                 if (ct != NULL) {
514                         if (likely(!nf_ct_is_dying(ct) &&
515                                    atomic_inc_not_zero(&ct->ct_general.use)))
516                                 break;
517                         else
518                                 ct = NULL;
519                 }
520
521                 if (cnt >= NF_CT_EVICTION_RANGE)
522                         break;
523
524                 hash = (hash + 1) % nf_conntrack_htable_size;
525         }
526         rcu_read_unlock();
527
528         if (!ct)
529                 return dropped;
530
531         if (del_timer(&ct->timeout)) {
532                 death_by_timeout((unsigned long)ct);
533                 dropped = 1;
534                 NF_CT_STAT_INC_ATOMIC(net, early_drop);
535         }
536         nf_ct_put(ct);
537         return dropped;
538 }
539
540 struct nf_conn *nf_conntrack_alloc(struct net *net,
541                                    const struct nf_conntrack_tuple *orig,
542                                    const struct nf_conntrack_tuple *repl,
543                                    gfp_t gfp)
544 {
545         struct nf_conn *ct;
546
547         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
548                 get_random_bytes(&nf_conntrack_hash_rnd,
549                                 sizeof(nf_conntrack_hash_rnd));
550                 nf_conntrack_hash_rnd_initted = 1;
551         }
552
553         /* We don't want any race condition at early drop stage */
554         atomic_inc(&net->ct.count);
555
556         if (nf_conntrack_max &&
557             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
558                 unsigned int hash = hash_conntrack(orig);
559                 if (!early_drop(net, hash)) {
560                         atomic_dec(&net->ct.count);
561                         if (net_ratelimit())
562                                 printk(KERN_WARNING
563                                        "nf_conntrack: table full, dropping"
564                                        " packet.\n");
565                         return ERR_PTR(-ENOMEM);
566                 }
567         }
568
569         /*
570          * Do not use kmem_cache_zalloc(), as this cache uses
571          * SLAB_DESTROY_BY_RCU.
572          */
573         ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
574         if (ct == NULL) {
575                 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
576                 atomic_dec(&net->ct.count);
577                 return ERR_PTR(-ENOMEM);
578         }
579         /*
580          * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
581          * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
582          */
583         memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
584                sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
585         spin_lock_init(&ct->lock);
586         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
587         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
588         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
589         ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev = NULL;
590         /* Don't set timer yet: wait for confirmation */
591         setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
592 #ifdef CONFIG_NET_NS
593         ct->ct_net = net;
594 #endif
595
596         /*
597          * changes to lookup keys must be done before setting refcnt to 1
598          */
599         smp_wmb();
600         atomic_set(&ct->ct_general.use, 1);
601         return ct;
602 }
603 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
604
605 void nf_conntrack_free(struct nf_conn *ct)
606 {
607         struct net *net = nf_ct_net(ct);
608
609         nf_ct_ext_destroy(ct);
610         atomic_dec(&net->ct.count);
611         nf_ct_ext_free(ct);
612         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
613 }
614 EXPORT_SYMBOL_GPL(nf_conntrack_free);
615
616 /* Allocate a new conntrack: we return -ENOMEM if classification
617    failed due to stress.  Otherwise it really is unclassifiable. */
618 static struct nf_conntrack_tuple_hash *
619 init_conntrack(struct net *net,
620                const struct nf_conntrack_tuple *tuple,
621                struct nf_conntrack_l3proto *l3proto,
622                struct nf_conntrack_l4proto *l4proto,
623                struct sk_buff *skb,
624                unsigned int dataoff)
625 {
626         struct nf_conn *ct;
627         struct nf_conn_help *help;
628         struct nf_conntrack_tuple repl_tuple;
629         struct nf_conntrack_expect *exp;
630
631         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
632                 pr_debug("Can't invert tuple.\n");
633                 return NULL;
634         }
635
636         ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC);
637         if (IS_ERR(ct)) {
638                 pr_debug("Can't allocate conntrack.\n");
639                 return (struct nf_conntrack_tuple_hash *)ct;
640         }
641
642         if (!l4proto->new(ct, skb, dataoff)) {
643                 nf_conntrack_free(ct);
644                 pr_debug("init conntrack: can't track with proto module\n");
645                 return NULL;
646         }
647
648         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
649         nf_ct_ecache_ext_add(ct, GFP_ATOMIC);
650
651         spin_lock_bh(&nf_conntrack_lock);
652         exp = nf_ct_find_expectation(net, tuple);
653         if (exp) {
654                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
655                          ct, exp);
656                 /* Welcome, Mr. Bond.  We've been expecting you... */
657                 __set_bit(IPS_EXPECTED_BIT, &ct->status);
658                 ct->master = exp->master;
659                 if (exp->helper) {
660                         help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
661                         if (help)
662                                 rcu_assign_pointer(help->helper, exp->helper);
663                 }
664
665 #ifdef CONFIG_NF_CONNTRACK_MARK
666                 ct->mark = exp->master->mark;
667 #endif
668 #ifdef CONFIG_NF_CONNTRACK_SECMARK
669                 ct->secmark = exp->master->secmark;
670 #endif
671                 nf_conntrack_get(&ct->master->ct_general);
672                 NF_CT_STAT_INC(net, expect_new);
673         } else {
674                 __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
675                 NF_CT_STAT_INC(net, new);
676         }
677
678         /* Overload tuple linked list to put us in unconfirmed list. */
679         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
680                        &net->ct.unconfirmed);
681
682         spin_unlock_bh(&nf_conntrack_lock);
683
684         if (exp) {
685                 if (exp->expectfn)
686                         exp->expectfn(ct, exp);
687                 nf_ct_expect_put(exp);
688         }
689
690         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
691 }
692
693 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
694 static inline struct nf_conn *
695 resolve_normal_ct(struct net *net,
696                   struct sk_buff *skb,
697                   unsigned int dataoff,
698                   u_int16_t l3num,
699                   u_int8_t protonum,
700                   struct nf_conntrack_l3proto *l3proto,
701                   struct nf_conntrack_l4proto *l4proto,
702                   int *set_reply,
703                   enum ip_conntrack_info *ctinfo)
704 {
705         struct nf_conntrack_tuple tuple;
706         struct nf_conntrack_tuple_hash *h;
707         struct nf_conn *ct;
708
709         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
710                              dataoff, l3num, protonum, &tuple, l3proto,
711                              l4proto)) {
712                 pr_debug("resolve_normal_ct: Can't get tuple\n");
713                 return NULL;
714         }
715
716         /* look for tuple match */
717         h = nf_conntrack_find_get(net, &tuple);
718         if (!h) {
719                 h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff);
720                 if (!h)
721                         return NULL;
722                 if (IS_ERR(h))
723                         return (void *)h;
724         }
725         ct = nf_ct_tuplehash_to_ctrack(h);
726
727         /* It exists; we have (non-exclusive) reference. */
728         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
729                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
730                 /* Please set reply bit if this packet OK */
731                 *set_reply = 1;
732         } else {
733                 /* Once we've had two way comms, always ESTABLISHED. */
734                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
735                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
736                         *ctinfo = IP_CT_ESTABLISHED;
737                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
738                         pr_debug("nf_conntrack_in: related packet for %p\n",
739                                  ct);
740                         *ctinfo = IP_CT_RELATED;
741                 } else {
742                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
743                         *ctinfo = IP_CT_NEW;
744                 }
745                 *set_reply = 0;
746         }
747         skb->nfct = &ct->ct_general;
748         skb->nfctinfo = *ctinfo;
749         return ct;
750 }
751
752 unsigned int
753 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
754                 struct sk_buff *skb)
755 {
756         struct nf_conn *ct;
757         enum ip_conntrack_info ctinfo;
758         struct nf_conntrack_l3proto *l3proto;
759         struct nf_conntrack_l4proto *l4proto;
760         unsigned int dataoff;
761         u_int8_t protonum;
762         int set_reply = 0;
763         int ret;
764
765         /* Previously seen (loopback or untracked)?  Ignore. */
766         if (skb->nfct) {
767                 NF_CT_STAT_INC_ATOMIC(net, ignore);
768                 return NF_ACCEPT;
769         }
770
771         /* rcu_read_lock()ed by nf_hook_slow */
772         l3proto = __nf_ct_l3proto_find(pf);
773         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
774                                    &dataoff, &protonum);
775         if (ret <= 0) {
776                 pr_debug("not prepared to track yet or error occured\n");
777                 NF_CT_STAT_INC_ATOMIC(net, error);
778                 NF_CT_STAT_INC_ATOMIC(net, invalid);
779                 return -ret;
780         }
781
782         l4proto = __nf_ct_l4proto_find(pf, protonum);
783
784         /* It may be an special packet, error, unclean...
785          * inverse of the return code tells to the netfilter
786          * core what to do with the packet. */
787         if (l4proto->error != NULL) {
788                 ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum);
789                 if (ret <= 0) {
790                         NF_CT_STAT_INC_ATOMIC(net, error);
791                         NF_CT_STAT_INC_ATOMIC(net, invalid);
792                         return -ret;
793                 }
794         }
795
796         ct = resolve_normal_ct(net, skb, dataoff, pf, protonum,
797                                l3proto, l4proto, &set_reply, &ctinfo);
798         if (!ct) {
799                 /* Not valid part of a connection */
800                 NF_CT_STAT_INC_ATOMIC(net, invalid);
801                 return NF_ACCEPT;
802         }
803
804         if (IS_ERR(ct)) {
805                 /* Too stressed to deal. */
806                 NF_CT_STAT_INC_ATOMIC(net, drop);
807                 return NF_DROP;
808         }
809
810         NF_CT_ASSERT(skb->nfct);
811
812         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
813         if (ret <= 0) {
814                 /* Invalid: inverse of the return code tells
815                  * the netfilter core what to do */
816                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
817                 nf_conntrack_put(skb->nfct);
818                 skb->nfct = NULL;
819                 NF_CT_STAT_INC_ATOMIC(net, invalid);
820                 if (ret == -NF_DROP)
821                         NF_CT_STAT_INC_ATOMIC(net, drop);
822                 return -ret;
823         }
824
825         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
826                 nf_conntrack_event_cache(IPCT_STATUS, ct);
827
828         return ret;
829 }
830 EXPORT_SYMBOL_GPL(nf_conntrack_in);
831
832 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
833                           const struct nf_conntrack_tuple *orig)
834 {
835         bool ret;
836
837         rcu_read_lock();
838         ret = nf_ct_invert_tuple(inverse, orig,
839                                  __nf_ct_l3proto_find(orig->src.l3num),
840                                  __nf_ct_l4proto_find(orig->src.l3num,
841                                                       orig->dst.protonum));
842         rcu_read_unlock();
843         return ret;
844 }
845 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
846
847 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
848    implicitly racy: see __nf_conntrack_confirm */
849 void nf_conntrack_alter_reply(struct nf_conn *ct,
850                               const struct nf_conntrack_tuple *newreply)
851 {
852         struct nf_conn_help *help = nfct_help(ct);
853
854         /* Should be unconfirmed, so not in hash table yet */
855         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
856
857         pr_debug("Altering reply tuple of %p to ", ct);
858         nf_ct_dump_tuple(newreply);
859
860         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
861         if (ct->master || (help && !hlist_empty(&help->expectations)))
862                 return;
863
864         rcu_read_lock();
865         __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
866         rcu_read_unlock();
867 }
868 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
869
870 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
871 void __nf_ct_refresh_acct(struct nf_conn *ct,
872                           enum ip_conntrack_info ctinfo,
873                           const struct sk_buff *skb,
874                           unsigned long extra_jiffies,
875                           int do_acct)
876 {
877         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
878         NF_CT_ASSERT(skb);
879
880         /* Only update if this is not a fixed timeout */
881         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
882                 goto acct;
883
884         /* If not in hash table, timer will not be active yet */
885         if (!nf_ct_is_confirmed(ct)) {
886                 ct->timeout.expires = extra_jiffies;
887         } else {
888                 unsigned long newtime = jiffies + extra_jiffies;
889
890                 /* Only update the timeout if the new timeout is at least
891                    HZ jiffies from the old timeout. Need del_timer for race
892                    avoidance (may already be dying). */
893                 if (newtime - ct->timeout.expires >= HZ)
894                         mod_timer_pending(&ct->timeout, newtime);
895         }
896
897 acct:
898         if (do_acct) {
899                 struct nf_conn_counter *acct;
900
901                 acct = nf_conn_acct_find(ct);
902                 if (acct) {
903                         spin_lock_bh(&ct->lock);
904                         acct[CTINFO2DIR(ctinfo)].packets++;
905                         acct[CTINFO2DIR(ctinfo)].bytes +=
906                                 skb->len - skb_network_offset(skb);
907                         spin_unlock_bh(&ct->lock);
908                 }
909         }
910 }
911 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
912
913 bool __nf_ct_kill_acct(struct nf_conn *ct,
914                        enum ip_conntrack_info ctinfo,
915                        const struct sk_buff *skb,
916                        int do_acct)
917 {
918         if (do_acct) {
919                 struct nf_conn_counter *acct;
920
921                 acct = nf_conn_acct_find(ct);
922                 if (acct) {
923                         spin_lock_bh(&ct->lock);
924                         acct[CTINFO2DIR(ctinfo)].packets++;
925                         acct[CTINFO2DIR(ctinfo)].bytes +=
926                                 skb->len - skb_network_offset(skb);
927                         spin_unlock_bh(&ct->lock);
928                 }
929         }
930
931         if (del_timer(&ct->timeout)) {
932                 ct->timeout.function((unsigned long)ct);
933                 return true;
934         }
935         return false;
936 }
937 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
938
939 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
940
941 #include <linux/netfilter/nfnetlink.h>
942 #include <linux/netfilter/nfnetlink_conntrack.h>
943 #include <linux/mutex.h>
944
945 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
946  * in ip_conntrack_core, since we don't want the protocols to autoload
947  * or depend on ctnetlink */
948 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
949                                const struct nf_conntrack_tuple *tuple)
950 {
951         NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
952         NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
953         return 0;
954
955 nla_put_failure:
956         return -1;
957 }
958 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
959
960 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
961         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
962         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
963 };
964 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
965
966 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
967                                struct nf_conntrack_tuple *t)
968 {
969         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
970                 return -EINVAL;
971
972         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
973         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
974
975         return 0;
976 }
977 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
978
979 int nf_ct_port_nlattr_tuple_size(void)
980 {
981         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
982 }
983 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
984 #endif
985
986 /* Used by ipt_REJECT and ip6t_REJECT. */
987 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
988 {
989         struct nf_conn *ct;
990         enum ip_conntrack_info ctinfo;
991
992         /* This ICMP is in reverse direction to the packet which caused it */
993         ct = nf_ct_get(skb, &ctinfo);
994         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
995                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
996         else
997                 ctinfo = IP_CT_RELATED;
998
999         /* Attach to new skbuff, and increment count */
1000         nskb->nfct = &ct->ct_general;
1001         nskb->nfctinfo = ctinfo;
1002         nf_conntrack_get(nskb->nfct);
1003 }
1004
1005 /* Bring out ya dead! */
1006 static struct nf_conn *
1007 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1008                 void *data, unsigned int *bucket)
1009 {
1010         struct nf_conntrack_tuple_hash *h;
1011         struct nf_conn *ct;
1012         struct hlist_nulls_node *n;
1013
1014         spin_lock_bh(&nf_conntrack_lock);
1015         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1016                 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1017                         ct = nf_ct_tuplehash_to_ctrack(h);
1018                         if (iter(ct, data))
1019                                 goto found;
1020                 }
1021         }
1022         hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1023                 ct = nf_ct_tuplehash_to_ctrack(h);
1024                 if (iter(ct, data))
1025                         set_bit(IPS_DYING_BIT, &ct->status);
1026         }
1027         spin_unlock_bh(&nf_conntrack_lock);
1028         return NULL;
1029 found:
1030         atomic_inc(&ct->ct_general.use);
1031         spin_unlock_bh(&nf_conntrack_lock);
1032         return ct;
1033 }
1034
1035 void nf_ct_iterate_cleanup(struct net *net,
1036                            int (*iter)(struct nf_conn *i, void *data),
1037                            void *data)
1038 {
1039         struct nf_conn *ct;
1040         unsigned int bucket = 0;
1041
1042         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1043                 /* Time to push up daises... */
1044                 if (del_timer(&ct->timeout))
1045                         death_by_timeout((unsigned long)ct);
1046                 /* ... else the timer will get him soon. */
1047
1048                 nf_ct_put(ct);
1049         }
1050 }
1051 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1052
1053 struct __nf_ct_flush_report {
1054         u32 pid;
1055         int report;
1056 };
1057
1058 static int kill_report(struct nf_conn *i, void *data)
1059 {
1060         struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1061
1062         /* If we fail to deliver the event, death_by_timeout() will retry */
1063         if (nf_conntrack_event_report(IPCT_DESTROY, i,
1064                                       fr->pid, fr->report) < 0)
1065                 return 1;
1066
1067         /* Avoid the delivery of the destroy event in death_by_timeout(). */
1068         set_bit(IPS_DYING_BIT, &i->status);
1069         return 1;
1070 }
1071
1072 static int kill_all(struct nf_conn *i, void *data)
1073 {
1074         return 1;
1075 }
1076
1077 void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size)
1078 {
1079         if (vmalloced)
1080                 vfree(hash);
1081         else
1082                 free_pages((unsigned long)hash,
1083                            get_order(sizeof(struct hlist_head) * size));
1084 }
1085 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1086
1087 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1088 {
1089         struct __nf_ct_flush_report fr = {
1090                 .pid    = pid,
1091                 .report = report,
1092         };
1093         nf_ct_iterate_cleanup(net, kill_report, &fr);
1094 }
1095 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1096
1097 static void nf_ct_release_dying_list(struct net *net)
1098 {
1099         struct nf_conntrack_tuple_hash *h;
1100         struct nf_conn *ct;
1101         struct hlist_nulls_node *n;
1102
1103         spin_lock_bh(&nf_conntrack_lock);
1104         hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) {
1105                 ct = nf_ct_tuplehash_to_ctrack(h);
1106                 /* never fails to remove them, no listeners at this point */
1107                 nf_ct_kill(ct);
1108         }
1109         spin_unlock_bh(&nf_conntrack_lock);
1110 }
1111
1112 static void nf_conntrack_cleanup_init_net(void)
1113 {
1114         /* wait until all references to nf_conntrack_untracked are dropped */
1115         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1116                 schedule();
1117
1118         nf_conntrack_helper_fini();
1119         nf_conntrack_proto_fini();
1120 }
1121
1122 static void nf_conntrack_cleanup_net(struct net *net)
1123 {
1124  i_see_dead_people:
1125         nf_ct_iterate_cleanup(net, kill_all, NULL);
1126         nf_ct_release_dying_list(net);
1127         if (atomic_read(&net->ct.count) != 0) {
1128                 schedule();
1129                 goto i_see_dead_people;
1130         }
1131
1132         nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1133                              nf_conntrack_htable_size);
1134         nf_conntrack_ecache_fini(net);
1135         nf_conntrack_acct_fini(net);
1136         nf_conntrack_expect_fini(net);
1137         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1138         kfree(net->ct.slabname);
1139         free_percpu(net->ct.stat);
1140 }
1141
1142 /* Mishearing the voices in his head, our hero wonders how he's
1143    supposed to kill the mall. */
1144 void nf_conntrack_cleanup(struct net *net)
1145 {
1146         if (net_eq(net, &init_net))
1147                 rcu_assign_pointer(ip_ct_attach, NULL);
1148
1149         /* This makes sure all current packets have passed through
1150            netfilter framework.  Roll on, two-stage module
1151            delete... */
1152         synchronize_net();
1153
1154         nf_conntrack_cleanup_net(net);
1155
1156         if (net_eq(net, &init_net)) {
1157                 rcu_assign_pointer(nf_ct_destroy, NULL);
1158                 nf_conntrack_cleanup_init_net();
1159         }
1160 }
1161
1162 void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls)
1163 {
1164         struct hlist_nulls_head *hash;
1165         unsigned int nr_slots, i;
1166         size_t sz;
1167
1168         *vmalloced = 0;
1169
1170         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1171         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1172         sz = nr_slots * sizeof(struct hlist_nulls_head);
1173         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1174                                         get_order(sz));
1175         if (!hash) {
1176                 *vmalloced = 1;
1177                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1178                 hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
1179         }
1180
1181         if (hash && nulls)
1182                 for (i = 0; i < nr_slots; i++)
1183                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1184
1185         return hash;
1186 }
1187 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1188
1189 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1190 {
1191         int i, bucket, vmalloced, old_vmalloced;
1192         unsigned int hashsize, old_size;
1193         int rnd;
1194         struct hlist_nulls_head *hash, *old_hash;
1195         struct nf_conntrack_tuple_hash *h;
1196
1197         /* On boot, we can set this without any fancy locking. */
1198         if (!nf_conntrack_htable_size)
1199                 return param_set_uint(val, kp);
1200
1201         hashsize = simple_strtoul(val, NULL, 0);
1202         if (!hashsize)
1203                 return -EINVAL;
1204
1205         hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1);
1206         if (!hash)
1207                 return -ENOMEM;
1208
1209         /* We have to rehahs for the new table anyway, so we also can
1210          * use a newrandom seed */
1211         get_random_bytes(&rnd, sizeof(rnd));
1212
1213         /* Lookups in the old hash might happen in parallel, which means we
1214          * might get false negatives during connection lookup. New connections
1215          * created because of a false negative won't make it into the hash
1216          * though since that required taking the lock.
1217          */
1218         spin_lock_bh(&nf_conntrack_lock);
1219         for (i = 0; i < nf_conntrack_htable_size; i++) {
1220                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1221                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1222                                         struct nf_conntrack_tuple_hash, hnnode);
1223                         hlist_nulls_del_rcu(&h->hnnode);
1224                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1225                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1226                 }
1227         }
1228         old_size = nf_conntrack_htable_size;
1229         old_vmalloced = init_net.ct.hash_vmalloc;
1230         old_hash = init_net.ct.hash;
1231
1232         nf_conntrack_htable_size = hashsize;
1233         init_net.ct.hash_vmalloc = vmalloced;
1234         init_net.ct.hash = hash;
1235         nf_conntrack_hash_rnd = rnd;
1236         spin_unlock_bh(&nf_conntrack_lock);
1237
1238         nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1239         return 0;
1240 }
1241 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1242
1243 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1244                   &nf_conntrack_htable_size, 0600);
1245
1246 static int nf_conntrack_init_init_net(void)
1247 {
1248         int max_factor = 8;
1249         int ret;
1250
1251         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1252          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1253         if (!nf_conntrack_htable_size) {
1254                 nf_conntrack_htable_size
1255                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1256                            / sizeof(struct hlist_head));
1257                 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1258                         nf_conntrack_htable_size = 16384;
1259                 if (nf_conntrack_htable_size < 32)
1260                         nf_conntrack_htable_size = 32;
1261
1262                 /* Use a max. factor of four by default to get the same max as
1263                  * with the old struct list_heads. When a table size is given
1264                  * we use the old value of 8 to avoid reducing the max.
1265                  * entries. */
1266                 max_factor = 4;
1267         }
1268         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1269
1270         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1271                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1272                nf_conntrack_max);
1273
1274         ret = nf_conntrack_proto_init();
1275         if (ret < 0)
1276                 goto err_proto;
1277
1278         ret = nf_conntrack_helper_init();
1279         if (ret < 0)
1280                 goto err_helper;
1281
1282         /* Set up fake conntrack: to never be deleted, not in any hashes */
1283 #ifdef CONFIG_NET_NS
1284         nf_conntrack_untracked.ct_net = &init_net;
1285 #endif
1286         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1287         /*  - and look it like as a confirmed connection */
1288         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1289
1290         return 0;
1291
1292 err_helper:
1293         nf_conntrack_proto_fini();
1294 err_proto:
1295         return ret;
1296 }
1297
1298 /*
1299  * We need to use special "null" values, not used in hash table
1300  */
1301 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1302 #define DYING_NULLS_VAL         ((1<<30)+1)
1303
1304 static int nf_conntrack_init_net(struct net *net)
1305 {
1306         int ret;
1307
1308         atomic_set(&net->ct.count, 0);
1309         INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1310         INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1311         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1312         if (!net->ct.stat) {
1313                 ret = -ENOMEM;
1314                 goto err_stat;
1315         }
1316
1317         net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1318         if (!net->ct.slabname) {
1319                 ret = -ENOMEM;
1320                 goto err_slabname;
1321         }
1322
1323         net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1324                                                         sizeof(struct nf_conn), 0,
1325                                                         SLAB_DESTROY_BY_RCU, NULL);
1326         if (!net->ct.nf_conntrack_cachep) {
1327                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1328                 ret = -ENOMEM;
1329                 goto err_cache;
1330         }
1331         net->ct.hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1332                                              &net->ct.hash_vmalloc, 1);
1333         if (!net->ct.hash) {
1334                 ret = -ENOMEM;
1335                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1336                 goto err_hash;
1337         }
1338         ret = nf_conntrack_expect_init(net);
1339         if (ret < 0)
1340                 goto err_expect;
1341         ret = nf_conntrack_acct_init(net);
1342         if (ret < 0)
1343                 goto err_acct;
1344         ret = nf_conntrack_ecache_init(net);
1345         if (ret < 0)
1346                 goto err_ecache;
1347
1348         return 0;
1349
1350 err_ecache:
1351         nf_conntrack_acct_fini(net);
1352 err_acct:
1353         nf_conntrack_expect_fini(net);
1354 err_expect:
1355         nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1356                              nf_conntrack_htable_size);
1357 err_hash:
1358         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1359 err_cache:
1360         kfree(net->ct.slabname);
1361 err_slabname:
1362         free_percpu(net->ct.stat);
1363 err_stat:
1364         return ret;
1365 }
1366
1367 s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
1368                         enum ip_conntrack_dir dir,
1369                         u32 seq);
1370 EXPORT_SYMBOL_GPL(nf_ct_nat_offset);
1371
1372 int nf_conntrack_init(struct net *net)
1373 {
1374         int ret;
1375
1376         if (net_eq(net, &init_net)) {
1377                 ret = nf_conntrack_init_init_net();
1378                 if (ret < 0)
1379                         goto out_init_net;
1380         }
1381         ret = nf_conntrack_init_net(net);
1382         if (ret < 0)
1383                 goto out_net;
1384
1385         if (net_eq(net, &init_net)) {
1386                 /* For use by REJECT target */
1387                 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1388                 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1389
1390                 /* Howto get NAT offsets */
1391                 rcu_assign_pointer(nf_ct_nat_offset, NULL);
1392         }
1393         return 0;
1394
1395 out_net:
1396         if (net_eq(net, &init_net))
1397                 nf_conntrack_cleanup_init_net();
1398 out_init_net:
1399         return ret;
1400 }