netfilter: nfnetlink: constify message attributes and headers
[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/skbuff.h>
18 #include <linux/proc_fs.h>
19 #include <linux/vmalloc.h>
20 #include <linux/stddef.h>
21 #include <linux/slab.h>
22 #include <linux/random.h>
23 #include <linux/jhash.h>
24 #include <linux/err.h>
25 #include <linux/percpu.h>
26 #include <linux/moduleparam.h>
27 #include <linux/notifier.h>
28 #include <linux/kernel.h>
29 #include <linux/netdevice.h>
30 #include <linux/socket.h>
31 #include <linux/mm.h>
32 #include <linux/rculist_nulls.h>
33
34 #include <net/netfilter/nf_conntrack.h>
35 #include <net/netfilter/nf_conntrack_l3proto.h>
36 #include <net/netfilter/nf_conntrack_l4proto.h>
37 #include <net/netfilter/nf_conntrack_expect.h>
38 #include <net/netfilter/nf_conntrack_helper.h>
39 #include <net/netfilter/nf_conntrack_core.h>
40 #include <net/netfilter/nf_conntrack_extend.h>
41 #include <net/netfilter/nf_conntrack_acct.h>
42 #include <net/netfilter/nf_conntrack_ecache.h>
43 #include <net/netfilter/nf_nat.h>
44 #include <net/netfilter/nf_nat_core.h>
45
46 #define NF_CONNTRACK_VERSION    "0.5.0"
47
48 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
49                                       enum nf_nat_manip_type manip,
50                                       const struct nlattr *attr) __read_mostly;
51 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
52
53 DEFINE_SPINLOCK(nf_conntrack_lock);
54 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
55
56 unsigned int nf_conntrack_htable_size __read_mostly;
57 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
58
59 unsigned int nf_conntrack_max __read_mostly;
60 EXPORT_SYMBOL_GPL(nf_conntrack_max);
61
62 struct nf_conn nf_conntrack_untracked __read_mostly;
63 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
64
65 static struct kmem_cache *nf_conntrack_cachep __read_mostly;
66
67 static int nf_conntrack_hash_rnd_initted;
68 static unsigned int nf_conntrack_hash_rnd;
69
70 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
71                                   unsigned int size, unsigned int rnd)
72 {
73         unsigned int n;
74         u_int32_t h;
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         h = jhash2((u32 *)tuple, n,
82                    rnd ^ (((__force __u16)tuple->dst.u.all << 16) |
83                           tuple->dst.protonum));
84
85         return ((u64)h * size) >> 32;
86 }
87
88 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
89 {
90         return __hash_conntrack(tuple, nf_conntrack_htable_size,
91                                 nf_conntrack_hash_rnd);
92 }
93
94 bool
95 nf_ct_get_tuple(const struct sk_buff *skb,
96                 unsigned int nhoff,
97                 unsigned int dataoff,
98                 u_int16_t l3num,
99                 u_int8_t protonum,
100                 struct nf_conntrack_tuple *tuple,
101                 const struct nf_conntrack_l3proto *l3proto,
102                 const struct nf_conntrack_l4proto *l4proto)
103 {
104         memset(tuple, 0, sizeof(*tuple));
105
106         tuple->src.l3num = l3num;
107         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
108                 return false;
109
110         tuple->dst.protonum = protonum;
111         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
112
113         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
114 }
115 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
116
117 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
118                        u_int16_t l3num, struct nf_conntrack_tuple *tuple)
119 {
120         struct nf_conntrack_l3proto *l3proto;
121         struct nf_conntrack_l4proto *l4proto;
122         unsigned int protoff;
123         u_int8_t protonum;
124         int ret;
125
126         rcu_read_lock();
127
128         l3proto = __nf_ct_l3proto_find(l3num);
129         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
130         if (ret != NF_ACCEPT) {
131                 rcu_read_unlock();
132                 return false;
133         }
134
135         l4proto = __nf_ct_l4proto_find(l3num, protonum);
136
137         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
138                               l3proto, l4proto);
139
140         rcu_read_unlock();
141         return ret;
142 }
143 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
144
145 bool
146 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
147                    const struct nf_conntrack_tuple *orig,
148                    const struct nf_conntrack_l3proto *l3proto,
149                    const struct nf_conntrack_l4proto *l4proto)
150 {
151         memset(inverse, 0, sizeof(*inverse));
152
153         inverse->src.l3num = orig->src.l3num;
154         if (l3proto->invert_tuple(inverse, orig) == 0)
155                 return false;
156
157         inverse->dst.dir = !orig->dst.dir;
158
159         inverse->dst.protonum = orig->dst.protonum;
160         return l4proto->invert_tuple(inverse, orig);
161 }
162 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
163
164 static void
165 clean_from_lists(struct nf_conn *ct)
166 {
167         pr_debug("clean_from_lists(%p)\n", ct);
168         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
169         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
170
171         /* Destroy all pending expectations */
172         nf_ct_remove_expectations(ct);
173 }
174
175 static void
176 destroy_conntrack(struct nf_conntrack *nfct)
177 {
178         struct nf_conn *ct = (struct nf_conn *)nfct;
179         struct net *net = nf_ct_net(ct);
180         struct nf_conntrack_l4proto *l4proto;
181
182         pr_debug("destroy_conntrack(%p)\n", ct);
183         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
184         NF_CT_ASSERT(!timer_pending(&ct->timeout));
185
186         /* To make sure we don't get any weird locking issues here:
187          * destroy_conntrack() MUST NOT be called with a write lock
188          * to nf_conntrack_lock!!! -HW */
189         rcu_read_lock();
190         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
191         if (l4proto && l4proto->destroy)
192                 l4proto->destroy(ct);
193
194         rcu_read_unlock();
195
196         spin_lock_bh(&nf_conntrack_lock);
197         /* Expectations will have been removed in clean_from_lists,
198          * except TFTP can create an expectation on the first packet,
199          * before connection is in the list, so we need to clean here,
200          * too. */
201         nf_ct_remove_expectations(ct);
202
203         /* We overload first tuple to link into unconfirmed list. */
204         if (!nf_ct_is_confirmed(ct)) {
205                 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
206                 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
207         }
208
209         NF_CT_STAT_INC(net, delete);
210         spin_unlock_bh(&nf_conntrack_lock);
211
212         if (ct->master)
213                 nf_ct_put(ct->master);
214
215         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
216         nf_conntrack_free(ct);
217 }
218
219 void nf_ct_delete_from_lists(struct nf_conn *ct)
220 {
221         struct net *net = nf_ct_net(ct);
222
223         nf_ct_helper_destroy(ct);
224         spin_lock_bh(&nf_conntrack_lock);
225         /* Inside lock so preempt is disabled on module removal path.
226          * Otherwise we can get spurious warnings. */
227         NF_CT_STAT_INC(net, delete_list);
228         clean_from_lists(ct);
229         spin_unlock_bh(&nf_conntrack_lock);
230 }
231 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
232
233 static void death_by_event(unsigned long ul_conntrack)
234 {
235         struct nf_conn *ct = (void *)ul_conntrack;
236         struct net *net = nf_ct_net(ct);
237
238         if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
239                 /* bad luck, let's retry again */
240                 ct->timeout.expires = jiffies +
241                         (random32() % net->ct.sysctl_events_retry_timeout);
242                 add_timer(&ct->timeout);
243                 return;
244         }
245         /* we've got the event delivered, now it's dying */
246         set_bit(IPS_DYING_BIT, &ct->status);
247         spin_lock(&nf_conntrack_lock);
248         hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
249         spin_unlock(&nf_conntrack_lock);
250         nf_ct_put(ct);
251 }
252
253 void nf_ct_insert_dying_list(struct nf_conn *ct)
254 {
255         struct net *net = nf_ct_net(ct);
256
257         /* add this conntrack to the dying list */
258         spin_lock_bh(&nf_conntrack_lock);
259         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
260                              &net->ct.dying);
261         spin_unlock_bh(&nf_conntrack_lock);
262         /* set a new timer to retry event delivery */
263         setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
264         ct->timeout.expires = jiffies +
265                 (random32() % net->ct.sysctl_events_retry_timeout);
266         add_timer(&ct->timeout);
267 }
268 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
269
270 static void death_by_timeout(unsigned long ul_conntrack)
271 {
272         struct nf_conn *ct = (void *)ul_conntrack;
273
274         if (!test_bit(IPS_DYING_BIT, &ct->status) &&
275             unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
276                 /* destroy event was not delivered */
277                 nf_ct_delete_from_lists(ct);
278                 nf_ct_insert_dying_list(ct);
279                 return;
280         }
281         set_bit(IPS_DYING_BIT, &ct->status);
282         nf_ct_delete_from_lists(ct);
283         nf_ct_put(ct);
284 }
285
286 /*
287  * Warning :
288  * - Caller must take a reference on returned object
289  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
290  * OR
291  * - Caller must lock nf_conntrack_lock before calling this function
292  */
293 struct nf_conntrack_tuple_hash *
294 __nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple)
295 {
296         struct nf_conntrack_tuple_hash *h;
297         struct hlist_nulls_node *n;
298         unsigned int hash = hash_conntrack(tuple);
299
300         /* Disable BHs the entire time since we normally need to disable them
301          * at least once for the stats anyway.
302          */
303         local_bh_disable();
304 begin:
305         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
306                 if (nf_ct_tuple_equal(tuple, &h->tuple)) {
307                         NF_CT_STAT_INC(net, found);
308                         local_bh_enable();
309                         return h;
310                 }
311                 NF_CT_STAT_INC(net, searched);
312         }
313         /*
314          * if the nulls value we got at the end of this lookup is
315          * not the expected one, we must restart lookup.
316          * We probably met an item that was moved to another chain.
317          */
318         if (get_nulls_value(n) != hash)
319                 goto begin;
320         local_bh_enable();
321
322         return NULL;
323 }
324 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
325
326 /* Find a connection corresponding to a tuple. */
327 struct nf_conntrack_tuple_hash *
328 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple)
329 {
330         struct nf_conntrack_tuple_hash *h;
331         struct nf_conn *ct;
332
333         rcu_read_lock();
334 begin:
335         h = __nf_conntrack_find(net, tuple);
336         if (h) {
337                 ct = nf_ct_tuplehash_to_ctrack(h);
338                 if (unlikely(nf_ct_is_dying(ct) ||
339                              !atomic_inc_not_zero(&ct->ct_general.use)))
340                         h = NULL;
341                 else {
342                         if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) {
343                                 nf_ct_put(ct);
344                                 goto begin;
345                         }
346                 }
347         }
348         rcu_read_unlock();
349
350         return h;
351 }
352 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
353
354 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
355                                        unsigned int hash,
356                                        unsigned int repl_hash)
357 {
358         struct net *net = nf_ct_net(ct);
359
360         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
361                            &net->ct.hash[hash]);
362         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
363                            &net->ct.hash[repl_hash]);
364 }
365
366 void nf_conntrack_hash_insert(struct nf_conn *ct)
367 {
368         unsigned int hash, repl_hash;
369
370         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
371         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
372
373         __nf_conntrack_hash_insert(ct, hash, repl_hash);
374 }
375 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
376
377 /* Confirm a connection given skb; places it in hash table */
378 int
379 __nf_conntrack_confirm(struct sk_buff *skb)
380 {
381         unsigned int hash, repl_hash;
382         struct nf_conntrack_tuple_hash *h;
383         struct nf_conn *ct;
384         struct nf_conn_help *help;
385         struct hlist_nulls_node *n;
386         enum ip_conntrack_info ctinfo;
387         struct net *net;
388
389         ct = nf_ct_get(skb, &ctinfo);
390         net = nf_ct_net(ct);
391
392         /* ipt_REJECT uses nf_conntrack_attach to attach related
393            ICMP/TCP RST packets in other direction.  Actual packet
394            which created connection will be IP_CT_NEW or for an
395            expected connection, IP_CT_RELATED. */
396         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
397                 return NF_ACCEPT;
398
399         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
400         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
401
402         /* We're not in hash table, and we refuse to set up related
403            connections for unconfirmed conns.  But packet copies and
404            REJECT will give spurious warnings here. */
405         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
406
407         /* No external references means noone else could have
408            confirmed us. */
409         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
410         pr_debug("Confirming conntrack %p\n", ct);
411
412         spin_lock_bh(&nf_conntrack_lock);
413
414         /* See if there's one in the list already, including reverse:
415            NAT could have grabbed it without realizing, since we're
416            not in the hash.  If there is, we lost race. */
417         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
418                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
419                                       &h->tuple))
420                         goto out;
421         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
422                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
423                                       &h->tuple))
424                         goto out;
425
426         /* Remove from unconfirmed list */
427         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
428
429         /* Timer relative to confirmation time, not original
430            setting time, otherwise we'd get timer wrap in
431            weird delay cases. */
432         ct->timeout.expires += jiffies;
433         add_timer(&ct->timeout);
434         atomic_inc(&ct->ct_general.use);
435         set_bit(IPS_CONFIRMED_BIT, &ct->status);
436
437         /* Since the lookup is lockless, hash insertion must be done after
438          * starting the timer and setting the CONFIRMED bit. The RCU barriers
439          * guarantee that no other CPU can find the conntrack before the above
440          * stores are visible.
441          */
442         __nf_conntrack_hash_insert(ct, hash, repl_hash);
443         NF_CT_STAT_INC(net, insert);
444         spin_unlock_bh(&nf_conntrack_lock);
445
446         help = nfct_help(ct);
447         if (help && help->helper)
448                 nf_conntrack_event_cache(IPCT_HELPER, ct);
449
450         nf_conntrack_event_cache(master_ct(ct) ?
451                                  IPCT_RELATED : IPCT_NEW, ct);
452         return NF_ACCEPT;
453
454 out:
455         NF_CT_STAT_INC(net, insert_failed);
456         spin_unlock_bh(&nf_conntrack_lock);
457         return NF_DROP;
458 }
459 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
460
461 /* Returns true if a connection correspondings to the tuple (required
462    for NAT). */
463 int
464 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
465                          const struct nf_conn *ignored_conntrack)
466 {
467         struct net *net = nf_ct_net(ignored_conntrack);
468         struct nf_conntrack_tuple_hash *h;
469         struct hlist_nulls_node *n;
470         unsigned int hash = hash_conntrack(tuple);
471
472         /* Disable BHs the entire time since we need to disable them at
473          * least once for the stats anyway.
474          */
475         rcu_read_lock_bh();
476         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
477                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
478                     nf_ct_tuple_equal(tuple, &h->tuple)) {
479                         NF_CT_STAT_INC(net, found);
480                         rcu_read_unlock_bh();
481                         return 1;
482                 }
483                 NF_CT_STAT_INC(net, searched);
484         }
485         rcu_read_unlock_bh();
486
487         return 0;
488 }
489 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
490
491 #define NF_CT_EVICTION_RANGE    8
492
493 /* There's a small race here where we may free a just-assured
494    connection.  Too bad: we're in trouble anyway. */
495 static noinline int early_drop(struct net *net, unsigned int hash)
496 {
497         /* Use oldest entry, which is roughly LRU */
498         struct nf_conntrack_tuple_hash *h;
499         struct nf_conn *ct = NULL, *tmp;
500         struct hlist_nulls_node *n;
501         unsigned int i, cnt = 0;
502         int dropped = 0;
503
504         rcu_read_lock();
505         for (i = 0; i < nf_conntrack_htable_size; i++) {
506                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
507                                          hnnode) {
508                         tmp = nf_ct_tuplehash_to_ctrack(h);
509                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
510                                 ct = tmp;
511                         cnt++;
512                 }
513
514                 if (ct && unlikely(nf_ct_is_dying(ct) ||
515                                    !atomic_inc_not_zero(&ct->ct_general.use)))
516                         ct = NULL;
517                 if (ct || cnt >= NF_CT_EVICTION_RANGE)
518                         break;
519                 hash = (hash + 1) % nf_conntrack_htable_size;
520         }
521         rcu_read_unlock();
522
523         if (!ct)
524                 return dropped;
525
526         if (del_timer(&ct->timeout)) {
527                 death_by_timeout((unsigned long)ct);
528                 dropped = 1;
529                 NF_CT_STAT_INC_ATOMIC(net, early_drop);
530         }
531         nf_ct_put(ct);
532         return dropped;
533 }
534
535 struct nf_conn *nf_conntrack_alloc(struct net *net,
536                                    const struct nf_conntrack_tuple *orig,
537                                    const struct nf_conntrack_tuple *repl,
538                                    gfp_t gfp)
539 {
540         struct nf_conn *ct;
541
542         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
543                 get_random_bytes(&nf_conntrack_hash_rnd,
544                                 sizeof(nf_conntrack_hash_rnd));
545                 nf_conntrack_hash_rnd_initted = 1;
546         }
547
548         /* We don't want any race condition at early drop stage */
549         atomic_inc(&net->ct.count);
550
551         if (nf_conntrack_max &&
552             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
553                 unsigned int hash = hash_conntrack(orig);
554                 if (!early_drop(net, hash)) {
555                         atomic_dec(&net->ct.count);
556                         if (net_ratelimit())
557                                 printk(KERN_WARNING
558                                        "nf_conntrack: table full, dropping"
559                                        " packet.\n");
560                         return ERR_PTR(-ENOMEM);
561                 }
562         }
563
564         /*
565          * Do not use kmem_cache_zalloc(), as this cache uses
566          * SLAB_DESTROY_BY_RCU.
567          */
568         ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
569         if (ct == NULL) {
570                 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
571                 atomic_dec(&net->ct.count);
572                 return ERR_PTR(-ENOMEM);
573         }
574         /*
575          * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
576          * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
577          */
578         memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
579                sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
580         spin_lock_init(&ct->lock);
581         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
582         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
583         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
584         ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev = NULL;
585         /* Don't set timer yet: wait for confirmation */
586         setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
587 #ifdef CONFIG_NET_NS
588         ct->ct_net = net;
589 #endif
590
591         /*
592          * changes to lookup keys must be done before setting refcnt to 1
593          */
594         smp_wmb();
595         atomic_set(&ct->ct_general.use, 1);
596         return ct;
597 }
598 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
599
600 void nf_conntrack_free(struct nf_conn *ct)
601 {
602         struct net *net = nf_ct_net(ct);
603
604         nf_ct_ext_destroy(ct);
605         atomic_dec(&net->ct.count);
606         nf_ct_ext_free(ct);
607         kmem_cache_free(nf_conntrack_cachep, ct);
608 }
609 EXPORT_SYMBOL_GPL(nf_conntrack_free);
610
611 /* Allocate a new conntrack: we return -ENOMEM if classification
612    failed due to stress.  Otherwise it really is unclassifiable. */
613 static struct nf_conntrack_tuple_hash *
614 init_conntrack(struct net *net,
615                const struct nf_conntrack_tuple *tuple,
616                struct nf_conntrack_l3proto *l3proto,
617                struct nf_conntrack_l4proto *l4proto,
618                struct sk_buff *skb,
619                unsigned int dataoff)
620 {
621         struct nf_conn *ct;
622         struct nf_conn_help *help;
623         struct nf_conntrack_tuple repl_tuple;
624         struct nf_conntrack_expect *exp;
625
626         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
627                 pr_debug("Can't invert tuple.\n");
628                 return NULL;
629         }
630
631         ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC);
632         if (IS_ERR(ct)) {
633                 pr_debug("Can't allocate conntrack.\n");
634                 return (struct nf_conntrack_tuple_hash *)ct;
635         }
636
637         if (!l4proto->new(ct, skb, dataoff)) {
638                 nf_conntrack_free(ct);
639                 pr_debug("init conntrack: can't track with proto module\n");
640                 return NULL;
641         }
642
643         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
644         nf_ct_ecache_ext_add(ct, GFP_ATOMIC);
645
646         spin_lock_bh(&nf_conntrack_lock);
647         exp = nf_ct_find_expectation(net, tuple);
648         if (exp) {
649                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
650                          ct, exp);
651                 /* Welcome, Mr. Bond.  We've been expecting you... */
652                 __set_bit(IPS_EXPECTED_BIT, &ct->status);
653                 ct->master = exp->master;
654                 if (exp->helper) {
655                         help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
656                         if (help)
657                                 rcu_assign_pointer(help->helper, exp->helper);
658                 }
659
660 #ifdef CONFIG_NF_CONNTRACK_MARK
661                 ct->mark = exp->master->mark;
662 #endif
663 #ifdef CONFIG_NF_CONNTRACK_SECMARK
664                 ct->secmark = exp->master->secmark;
665 #endif
666                 nf_conntrack_get(&ct->master->ct_general);
667                 NF_CT_STAT_INC(net, expect_new);
668         } else {
669                 __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
670                 NF_CT_STAT_INC(net, new);
671         }
672
673         /* Overload tuple linked list to put us in unconfirmed list. */
674         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
675                        &net->ct.unconfirmed);
676
677         spin_unlock_bh(&nf_conntrack_lock);
678
679         if (exp) {
680                 if (exp->expectfn)
681                         exp->expectfn(ct, exp);
682                 nf_ct_expect_put(exp);
683         }
684
685         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
686 }
687
688 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
689 static inline struct nf_conn *
690 resolve_normal_ct(struct net *net,
691                   struct sk_buff *skb,
692                   unsigned int dataoff,
693                   u_int16_t l3num,
694                   u_int8_t protonum,
695                   struct nf_conntrack_l3proto *l3proto,
696                   struct nf_conntrack_l4proto *l4proto,
697                   int *set_reply,
698                   enum ip_conntrack_info *ctinfo)
699 {
700         struct nf_conntrack_tuple tuple;
701         struct nf_conntrack_tuple_hash *h;
702         struct nf_conn *ct;
703
704         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
705                              dataoff, l3num, protonum, &tuple, l3proto,
706                              l4proto)) {
707                 pr_debug("resolve_normal_ct: Can't get tuple\n");
708                 return NULL;
709         }
710
711         /* look for tuple match */
712         h = nf_conntrack_find_get(net, &tuple);
713         if (!h) {
714                 h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff);
715                 if (!h)
716                         return NULL;
717                 if (IS_ERR(h))
718                         return (void *)h;
719         }
720         ct = nf_ct_tuplehash_to_ctrack(h);
721
722         /* It exists; we have (non-exclusive) reference. */
723         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
724                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
725                 /* Please set reply bit if this packet OK */
726                 *set_reply = 1;
727         } else {
728                 /* Once we've had two way comms, always ESTABLISHED. */
729                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
730                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
731                         *ctinfo = IP_CT_ESTABLISHED;
732                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
733                         pr_debug("nf_conntrack_in: related packet for %p\n",
734                                  ct);
735                         *ctinfo = IP_CT_RELATED;
736                 } else {
737                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
738                         *ctinfo = IP_CT_NEW;
739                 }
740                 *set_reply = 0;
741         }
742         skb->nfct = &ct->ct_general;
743         skb->nfctinfo = *ctinfo;
744         return ct;
745 }
746
747 unsigned int
748 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
749                 struct sk_buff *skb)
750 {
751         struct nf_conn *ct;
752         enum ip_conntrack_info ctinfo;
753         struct nf_conntrack_l3proto *l3proto;
754         struct nf_conntrack_l4proto *l4proto;
755         unsigned int dataoff;
756         u_int8_t protonum;
757         int set_reply = 0;
758         int ret;
759
760         /* Previously seen (loopback or untracked)?  Ignore. */
761         if (skb->nfct) {
762                 NF_CT_STAT_INC_ATOMIC(net, ignore);
763                 return NF_ACCEPT;
764         }
765
766         /* rcu_read_lock()ed by nf_hook_slow */
767         l3proto = __nf_ct_l3proto_find(pf);
768         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
769                                    &dataoff, &protonum);
770         if (ret <= 0) {
771                 pr_debug("not prepared to track yet or error occured\n");
772                 NF_CT_STAT_INC_ATOMIC(net, error);
773                 NF_CT_STAT_INC_ATOMIC(net, invalid);
774                 return -ret;
775         }
776
777         l4proto = __nf_ct_l4proto_find(pf, protonum);
778
779         /* It may be an special packet, error, unclean...
780          * inverse of the return code tells to the netfilter
781          * core what to do with the packet. */
782         if (l4proto->error != NULL) {
783                 ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum);
784                 if (ret <= 0) {
785                         NF_CT_STAT_INC_ATOMIC(net, error);
786                         NF_CT_STAT_INC_ATOMIC(net, invalid);
787                         return -ret;
788                 }
789         }
790
791         ct = resolve_normal_ct(net, skb, dataoff, pf, protonum,
792                                l3proto, l4proto, &set_reply, &ctinfo);
793         if (!ct) {
794                 /* Not valid part of a connection */
795                 NF_CT_STAT_INC_ATOMIC(net, invalid);
796                 return NF_ACCEPT;
797         }
798
799         if (IS_ERR(ct)) {
800                 /* Too stressed to deal. */
801                 NF_CT_STAT_INC_ATOMIC(net, drop);
802                 return NF_DROP;
803         }
804
805         NF_CT_ASSERT(skb->nfct);
806
807         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
808         if (ret <= 0) {
809                 /* Invalid: inverse of the return code tells
810                  * the netfilter core what to do */
811                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
812                 nf_conntrack_put(skb->nfct);
813                 skb->nfct = NULL;
814                 NF_CT_STAT_INC_ATOMIC(net, invalid);
815                 if (ret == -NF_DROP)
816                         NF_CT_STAT_INC_ATOMIC(net, drop);
817                 return -ret;
818         }
819
820         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
821                 nf_conntrack_event_cache(IPCT_STATUS, ct);
822
823         return ret;
824 }
825 EXPORT_SYMBOL_GPL(nf_conntrack_in);
826
827 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
828                           const struct nf_conntrack_tuple *orig)
829 {
830         bool ret;
831
832         rcu_read_lock();
833         ret = nf_ct_invert_tuple(inverse, orig,
834                                  __nf_ct_l3proto_find(orig->src.l3num),
835                                  __nf_ct_l4proto_find(orig->src.l3num,
836                                                       orig->dst.protonum));
837         rcu_read_unlock();
838         return ret;
839 }
840 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
841
842 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
843    implicitly racy: see __nf_conntrack_confirm */
844 void nf_conntrack_alter_reply(struct nf_conn *ct,
845                               const struct nf_conntrack_tuple *newreply)
846 {
847         struct nf_conn_help *help = nfct_help(ct);
848
849         /* Should be unconfirmed, so not in hash table yet */
850         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
851
852         pr_debug("Altering reply tuple of %p to ", ct);
853         nf_ct_dump_tuple(newreply);
854
855         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
856         if (ct->master || (help && !hlist_empty(&help->expectations)))
857                 return;
858
859         rcu_read_lock();
860         __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
861         rcu_read_unlock();
862 }
863 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
864
865 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
866 void __nf_ct_refresh_acct(struct nf_conn *ct,
867                           enum ip_conntrack_info ctinfo,
868                           const struct sk_buff *skb,
869                           unsigned long extra_jiffies,
870                           int do_acct)
871 {
872         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
873         NF_CT_ASSERT(skb);
874
875         /* Only update if this is not a fixed timeout */
876         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
877                 goto acct;
878
879         /* If not in hash table, timer will not be active yet */
880         if (!nf_ct_is_confirmed(ct)) {
881                 ct->timeout.expires = extra_jiffies;
882         } else {
883                 unsigned long newtime = jiffies + extra_jiffies;
884
885                 /* Only update the timeout if the new timeout is at least
886                    HZ jiffies from the old timeout. Need del_timer for race
887                    avoidance (may already be dying). */
888                 if (newtime - ct->timeout.expires >= HZ)
889                         mod_timer_pending(&ct->timeout, newtime);
890         }
891
892 acct:
893         if (do_acct) {
894                 struct nf_conn_counter *acct;
895
896                 acct = nf_conn_acct_find(ct);
897                 if (acct) {
898                         spin_lock_bh(&ct->lock);
899                         acct[CTINFO2DIR(ctinfo)].packets++;
900                         acct[CTINFO2DIR(ctinfo)].bytes +=
901                                 skb->len - skb_network_offset(skb);
902                         spin_unlock_bh(&ct->lock);
903                 }
904         }
905 }
906 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
907
908 bool __nf_ct_kill_acct(struct nf_conn *ct,
909                        enum ip_conntrack_info ctinfo,
910                        const struct sk_buff *skb,
911                        int do_acct)
912 {
913         if (do_acct) {
914                 struct nf_conn_counter *acct;
915
916                 acct = nf_conn_acct_find(ct);
917                 if (acct) {
918                         spin_lock_bh(&ct->lock);
919                         acct[CTINFO2DIR(ctinfo)].packets++;
920                         acct[CTINFO2DIR(ctinfo)].bytes +=
921                                 skb->len - skb_network_offset(skb);
922                         spin_unlock_bh(&ct->lock);
923                 }
924         }
925
926         if (del_timer(&ct->timeout)) {
927                 ct->timeout.function((unsigned long)ct);
928                 return true;
929         }
930         return false;
931 }
932 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
933
934 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
935
936 #include <linux/netfilter/nfnetlink.h>
937 #include <linux/netfilter/nfnetlink_conntrack.h>
938 #include <linux/mutex.h>
939
940 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
941  * in ip_conntrack_core, since we don't want the protocols to autoload
942  * or depend on ctnetlink */
943 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
944                                const struct nf_conntrack_tuple *tuple)
945 {
946         NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
947         NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
948         return 0;
949
950 nla_put_failure:
951         return -1;
952 }
953 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
954
955 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
956         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
957         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
958 };
959 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
960
961 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
962                                struct nf_conntrack_tuple *t)
963 {
964         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
965                 return -EINVAL;
966
967         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
968         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
969
970         return 0;
971 }
972 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
973
974 int nf_ct_port_nlattr_tuple_size(void)
975 {
976         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
977 }
978 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
979 #endif
980
981 /* Used by ipt_REJECT and ip6t_REJECT. */
982 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
983 {
984         struct nf_conn *ct;
985         enum ip_conntrack_info ctinfo;
986
987         /* This ICMP is in reverse direction to the packet which caused it */
988         ct = nf_ct_get(skb, &ctinfo);
989         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
990                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
991         else
992                 ctinfo = IP_CT_RELATED;
993
994         /* Attach to new skbuff, and increment count */
995         nskb->nfct = &ct->ct_general;
996         nskb->nfctinfo = ctinfo;
997         nf_conntrack_get(nskb->nfct);
998 }
999
1000 /* Bring out ya dead! */
1001 static struct nf_conn *
1002 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1003                 void *data, unsigned int *bucket)
1004 {
1005         struct nf_conntrack_tuple_hash *h;
1006         struct nf_conn *ct;
1007         struct hlist_nulls_node *n;
1008
1009         spin_lock_bh(&nf_conntrack_lock);
1010         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1011                 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1012                         ct = nf_ct_tuplehash_to_ctrack(h);
1013                         if (iter(ct, data))
1014                                 goto found;
1015                 }
1016         }
1017         hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1018                 ct = nf_ct_tuplehash_to_ctrack(h);
1019                 if (iter(ct, data))
1020                         set_bit(IPS_DYING_BIT, &ct->status);
1021         }
1022         spin_unlock_bh(&nf_conntrack_lock);
1023         return NULL;
1024 found:
1025         atomic_inc(&ct->ct_general.use);
1026         spin_unlock_bh(&nf_conntrack_lock);
1027         return ct;
1028 }
1029
1030 void nf_ct_iterate_cleanup(struct net *net,
1031                            int (*iter)(struct nf_conn *i, void *data),
1032                            void *data)
1033 {
1034         struct nf_conn *ct;
1035         unsigned int bucket = 0;
1036
1037         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1038                 /* Time to push up daises... */
1039                 if (del_timer(&ct->timeout))
1040                         death_by_timeout((unsigned long)ct);
1041                 /* ... else the timer will get him soon. */
1042
1043                 nf_ct_put(ct);
1044         }
1045 }
1046 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1047
1048 struct __nf_ct_flush_report {
1049         u32 pid;
1050         int report;
1051 };
1052
1053 static int kill_report(struct nf_conn *i, void *data)
1054 {
1055         struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1056
1057         /* If we fail to deliver the event, death_by_timeout() will retry */
1058         if (nf_conntrack_event_report(IPCT_DESTROY, i,
1059                                       fr->pid, fr->report) < 0)
1060                 return 1;
1061
1062         /* Avoid the delivery of the destroy event in death_by_timeout(). */
1063         set_bit(IPS_DYING_BIT, &i->status);
1064         return 1;
1065 }
1066
1067 static int kill_all(struct nf_conn *i, void *data)
1068 {
1069         return 1;
1070 }
1071
1072 void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size)
1073 {
1074         if (vmalloced)
1075                 vfree(hash);
1076         else
1077                 free_pages((unsigned long)hash,
1078                            get_order(sizeof(struct hlist_head) * size));
1079 }
1080 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1081
1082 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1083 {
1084         struct __nf_ct_flush_report fr = {
1085                 .pid    = pid,
1086                 .report = report,
1087         };
1088         nf_ct_iterate_cleanup(net, kill_report, &fr);
1089 }
1090 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1091
1092 static void nf_ct_release_dying_list(void)
1093 {
1094         struct nf_conntrack_tuple_hash *h;
1095         struct nf_conn *ct;
1096         struct hlist_nulls_node *n;
1097
1098         spin_lock_bh(&nf_conntrack_lock);
1099         hlist_nulls_for_each_entry(h, n, &init_net.ct.dying, hnnode) {
1100                 ct = nf_ct_tuplehash_to_ctrack(h);
1101                 /* never fails to remove them, no listeners at this point */
1102                 nf_ct_kill(ct);
1103         }
1104         spin_unlock_bh(&nf_conntrack_lock);
1105 }
1106
1107 static void nf_conntrack_cleanup_init_net(void)
1108 {
1109         nf_conntrack_helper_fini();
1110         nf_conntrack_proto_fini();
1111         kmem_cache_destroy(nf_conntrack_cachep);
1112 }
1113
1114 static void nf_conntrack_cleanup_net(struct net *net)
1115 {
1116  i_see_dead_people:
1117         nf_ct_iterate_cleanup(net, kill_all, NULL);
1118         nf_ct_release_dying_list();
1119         if (atomic_read(&net->ct.count) != 0) {
1120                 schedule();
1121                 goto i_see_dead_people;
1122         }
1123         /* wait until all references to nf_conntrack_untracked are dropped */
1124         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1125                 schedule();
1126
1127         nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1128                              nf_conntrack_htable_size);
1129         nf_conntrack_ecache_fini(net);
1130         nf_conntrack_acct_fini(net);
1131         nf_conntrack_expect_fini(net);
1132         free_percpu(net->ct.stat);
1133 }
1134
1135 /* Mishearing the voices in his head, our hero wonders how he's
1136    supposed to kill the mall. */
1137 void nf_conntrack_cleanup(struct net *net)
1138 {
1139         if (net_eq(net, &init_net))
1140                 rcu_assign_pointer(ip_ct_attach, NULL);
1141
1142         /* This makes sure all current packets have passed through
1143            netfilter framework.  Roll on, two-stage module
1144            delete... */
1145         synchronize_net();
1146
1147         nf_conntrack_cleanup_net(net);
1148
1149         if (net_eq(net, &init_net)) {
1150                 rcu_assign_pointer(nf_ct_destroy, NULL);
1151                 nf_conntrack_cleanup_init_net();
1152         }
1153 }
1154
1155 void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls)
1156 {
1157         struct hlist_nulls_head *hash;
1158         unsigned int nr_slots, i;
1159         size_t sz;
1160
1161         *vmalloced = 0;
1162
1163         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1164         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1165         sz = nr_slots * sizeof(struct hlist_nulls_head);
1166         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1167                                         get_order(sz));
1168         if (!hash) {
1169                 *vmalloced = 1;
1170                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1171                 hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
1172         }
1173
1174         if (hash && nulls)
1175                 for (i = 0; i < nr_slots; i++)
1176                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1177
1178         return hash;
1179 }
1180 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1181
1182 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1183 {
1184         int i, bucket, vmalloced, old_vmalloced;
1185         unsigned int hashsize, old_size;
1186         int rnd;
1187         struct hlist_nulls_head *hash, *old_hash;
1188         struct nf_conntrack_tuple_hash *h;
1189
1190         /* On boot, we can set this without any fancy locking. */
1191         if (!nf_conntrack_htable_size)
1192                 return param_set_uint(val, kp);
1193
1194         hashsize = simple_strtoul(val, NULL, 0);
1195         if (!hashsize)
1196                 return -EINVAL;
1197
1198         hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1);
1199         if (!hash)
1200                 return -ENOMEM;
1201
1202         /* We have to rehahs for the new table anyway, so we also can
1203          * use a newrandom seed */
1204         get_random_bytes(&rnd, sizeof(rnd));
1205
1206         /* Lookups in the old hash might happen in parallel, which means we
1207          * might get false negatives during connection lookup. New connections
1208          * created because of a false negative won't make it into the hash
1209          * though since that required taking the lock.
1210          */
1211         spin_lock_bh(&nf_conntrack_lock);
1212         for (i = 0; i < nf_conntrack_htable_size; i++) {
1213                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1214                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1215                                         struct nf_conntrack_tuple_hash, hnnode);
1216                         hlist_nulls_del_rcu(&h->hnnode);
1217                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1218                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1219                 }
1220         }
1221         old_size = nf_conntrack_htable_size;
1222         old_vmalloced = init_net.ct.hash_vmalloc;
1223         old_hash = init_net.ct.hash;
1224
1225         nf_conntrack_htable_size = hashsize;
1226         init_net.ct.hash_vmalloc = vmalloced;
1227         init_net.ct.hash = hash;
1228         nf_conntrack_hash_rnd = rnd;
1229         spin_unlock_bh(&nf_conntrack_lock);
1230
1231         nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1232         return 0;
1233 }
1234 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1235
1236 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1237                   &nf_conntrack_htable_size, 0600);
1238
1239 static int nf_conntrack_init_init_net(void)
1240 {
1241         int max_factor = 8;
1242         int ret;
1243
1244         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1245          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1246         if (!nf_conntrack_htable_size) {
1247                 nf_conntrack_htable_size
1248                         = (((num_physpages << PAGE_SHIFT) / 16384)
1249                            / sizeof(struct hlist_head));
1250                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1251                         nf_conntrack_htable_size = 16384;
1252                 if (nf_conntrack_htable_size < 32)
1253                         nf_conntrack_htable_size = 32;
1254
1255                 /* Use a max. factor of four by default to get the same max as
1256                  * with the old struct list_heads. When a table size is given
1257                  * we use the old value of 8 to avoid reducing the max.
1258                  * entries. */
1259                 max_factor = 4;
1260         }
1261         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1262
1263         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1264                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1265                nf_conntrack_max);
1266
1267         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1268                                                 sizeof(struct nf_conn),
1269                                                 0, SLAB_DESTROY_BY_RCU, NULL);
1270         if (!nf_conntrack_cachep) {
1271                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1272                 ret = -ENOMEM;
1273                 goto err_cache;
1274         }
1275
1276         ret = nf_conntrack_proto_init();
1277         if (ret < 0)
1278                 goto err_proto;
1279
1280         ret = nf_conntrack_helper_init();
1281         if (ret < 0)
1282                 goto err_helper;
1283
1284         return 0;
1285
1286 err_helper:
1287         nf_conntrack_proto_fini();
1288 err_proto:
1289         kmem_cache_destroy(nf_conntrack_cachep);
1290 err_cache:
1291         return ret;
1292 }
1293
1294 /*
1295  * We need to use special "null" values, not used in hash table
1296  */
1297 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1298 #define DYING_NULLS_VAL         ((1<<30)+1)
1299
1300 static int nf_conntrack_init_net(struct net *net)
1301 {
1302         int ret;
1303
1304         atomic_set(&net->ct.count, 0);
1305         INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1306         INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1307         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1308         if (!net->ct.stat) {
1309                 ret = -ENOMEM;
1310                 goto err_stat;
1311         }
1312         net->ct.hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1313                                              &net->ct.hash_vmalloc, 1);
1314         if (!net->ct.hash) {
1315                 ret = -ENOMEM;
1316                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1317                 goto err_hash;
1318         }
1319         ret = nf_conntrack_expect_init(net);
1320         if (ret < 0)
1321                 goto err_expect;
1322         ret = nf_conntrack_acct_init(net);
1323         if (ret < 0)
1324                 goto err_acct;
1325         ret = nf_conntrack_ecache_init(net);
1326         if (ret < 0)
1327                 goto err_ecache;
1328
1329         /* Set up fake conntrack:
1330             - to never be deleted, not in any hashes */
1331 #ifdef CONFIG_NET_NS
1332         nf_conntrack_untracked.ct_net = &init_net;
1333 #endif
1334         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1335         /*  - and look it like as a confirmed connection */
1336         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1337
1338         return 0;
1339
1340 err_ecache:
1341         nf_conntrack_acct_fini(net);
1342 err_acct:
1343         nf_conntrack_expect_fini(net);
1344 err_expect:
1345         nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1346                              nf_conntrack_htable_size);
1347 err_hash:
1348         free_percpu(net->ct.stat);
1349 err_stat:
1350         return ret;
1351 }
1352
1353 int nf_conntrack_init(struct net *net)
1354 {
1355         int ret;
1356
1357         if (net_eq(net, &init_net)) {
1358                 ret = nf_conntrack_init_init_net();
1359                 if (ret < 0)
1360                         goto out_init_net;
1361         }
1362         ret = nf_conntrack_init_net(net);
1363         if (ret < 0)
1364                 goto out_net;
1365
1366         if (net_eq(net, &init_net)) {
1367                 /* For use by REJECT target */
1368                 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1369                 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1370         }
1371         return 0;
1372
1373 out_net:
1374         if (net_eq(net, &init_net))
1375                 nf_conntrack_cleanup_init_net();
1376 out_init_net:
1377         return ret;
1378 }