[NETFILTER]: nf_conntrack: properly use RCU API for nf_ct_protos/nf_ct_l3protos arrays
[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  * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
14  *      - new API and handling of conntrack/nat helpers
15  *      - now capable of multiple expectations for one master
16  * 16 Jul 2002: Harald Welte <laforge@gnumonks.org>
17  *      - add usage/reference counts to ip_conntrack_expect
18  *      - export ip_conntrack[_expect]_{find_get,put} functions
19  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
20  *      - generalize L3 protocol denendent part.
21  * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
22  *      - add support various size of conntrack structures.
23  * 26 Jan 2006: Harald Welte <laforge@netfilter.org>
24  *      - restructure nf_conn (introduce nf_conn_help)
25  *      - redesign 'features' how they were originally intended
26  * 26 Feb 2006: Pablo Neira Ayuso <pablo@eurodev.net>
27  *      - add support for L3 protocol module load on demand.
28  *
29  * Derived from net/ipv4/netfilter/ip_conntrack_core.c
30  */
31
32 #include <linux/types.h>
33 #include <linux/netfilter.h>
34 #include <linux/module.h>
35 #include <linux/skbuff.h>
36 #include <linux/proc_fs.h>
37 #include <linux/vmalloc.h>
38 #include <linux/stddef.h>
39 #include <linux/slab.h>
40 #include <linux/random.h>
41 #include <linux/jhash.h>
42 #include <linux/err.h>
43 #include <linux/percpu.h>
44 #include <linux/moduleparam.h>
45 #include <linux/notifier.h>
46 #include <linux/kernel.h>
47 #include <linux/netdevice.h>
48 #include <linux/socket.h>
49 #include <linux/mm.h>
50
51 #include <net/netfilter/nf_conntrack.h>
52 #include <net/netfilter/nf_conntrack_l3proto.h>
53 #include <net/netfilter/nf_conntrack_l4proto.h>
54 #include <net/netfilter/nf_conntrack_expect.h>
55 #include <net/netfilter/nf_conntrack_helper.h>
56 #include <net/netfilter/nf_conntrack_core.h>
57
58 #define NF_CONNTRACK_VERSION    "0.5.0"
59
60 #if 0
61 #define DEBUGP printk
62 #else
63 #define DEBUGP(format, args...)
64 #endif
65
66 DEFINE_RWLOCK(nf_conntrack_lock);
67 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
68
69 /* nf_conntrack_standalone needs this */
70 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
71 EXPORT_SYMBOL_GPL(nf_conntrack_count);
72
73 void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
74 EXPORT_SYMBOL_GPL(nf_conntrack_destroyed);
75
76 unsigned int nf_conntrack_htable_size __read_mostly;
77 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
78
79 int nf_conntrack_max __read_mostly;
80 EXPORT_SYMBOL_GPL(nf_conntrack_max);
81
82 struct list_head *nf_conntrack_hash __read_mostly;
83 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
84
85 struct nf_conn nf_conntrack_untracked __read_mostly;
86 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
87
88 unsigned int nf_ct_log_invalid __read_mostly;
89 LIST_HEAD(unconfirmed);
90 static int nf_conntrack_vmalloc __read_mostly;
91
92 static unsigned int nf_conntrack_next_id;
93
94 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
95 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
96
97 /*
98  * This scheme offers various size of "struct nf_conn" dependent on
99  * features(helper, nat, ...)
100  */
101
102 #define NF_CT_FEATURES_NAMELEN  256
103 static struct {
104         /* name of slab cache. printed in /proc/slabinfo */
105         char *name;
106
107         /* size of slab cache */
108         size_t size;
109
110         /* slab cache pointer */
111         struct kmem_cache *cachep;
112
113         /* allocated slab cache + modules which uses this slab cache */
114         int use;
115
116 } nf_ct_cache[NF_CT_F_NUM];
117
118 /* protect members of nf_ct_cache except of "use" */
119 DEFINE_RWLOCK(nf_ct_cache_lock);
120
121 /* This avoids calling kmem_cache_create() with same name simultaneously */
122 static DEFINE_MUTEX(nf_ct_cache_mutex);
123
124 static int nf_conntrack_hash_rnd_initted;
125 static unsigned int nf_conntrack_hash_rnd;
126
127 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
128                                   unsigned int size, unsigned int rnd)
129 {
130         unsigned int a, b;
131         a = jhash((void *)tuple->src.u3.all, sizeof(tuple->src.u3.all),
132                   ((tuple->src.l3num) << 16) | tuple->dst.protonum);
133         b = jhash((void *)tuple->dst.u3.all, sizeof(tuple->dst.u3.all),
134                         (tuple->src.u.all << 16) | tuple->dst.u.all);
135
136         return jhash_2words(a, b, rnd) % size;
137 }
138
139 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
140 {
141         return __hash_conntrack(tuple, nf_conntrack_htable_size,
142                                 nf_conntrack_hash_rnd);
143 }
144
145 int nf_conntrack_register_cache(u_int32_t features, const char *name,
146                                 size_t size)
147 {
148         int ret = 0;
149         char *cache_name;
150         struct kmem_cache *cachep;
151
152         DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
153                features, name, size);
154
155         if (features < NF_CT_F_BASIC || features >= NF_CT_F_NUM) {
156                 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
157                         features);
158                 return -EINVAL;
159         }
160
161         mutex_lock(&nf_ct_cache_mutex);
162
163         write_lock_bh(&nf_ct_cache_lock);
164         /* e.g: multiple helpers are loaded */
165         if (nf_ct_cache[features].use > 0) {
166                 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
167                 if ((!strncmp(nf_ct_cache[features].name, name,
168                               NF_CT_FEATURES_NAMELEN))
169                     && nf_ct_cache[features].size == size) {
170                         DEBUGP("nf_conntrack_register_cache: reusing.\n");
171                         nf_ct_cache[features].use++;
172                         ret = 0;
173                 } else
174                         ret = -EBUSY;
175
176                 write_unlock_bh(&nf_ct_cache_lock);
177                 mutex_unlock(&nf_ct_cache_mutex);
178                 return ret;
179         }
180         write_unlock_bh(&nf_ct_cache_lock);
181
182         /*
183          * The memory space for name of slab cache must be alive until
184          * cache is destroyed.
185          */
186         cache_name = kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN, GFP_ATOMIC);
187         if (cache_name == NULL) {
188                 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
189                 ret = -ENOMEM;
190                 goto out_up_mutex;
191         }
192
193         if (strlcpy(cache_name, name, NF_CT_FEATURES_NAMELEN)
194                                                 >= NF_CT_FEATURES_NAMELEN) {
195                 printk("nf_conntrack_register_cache: name too long\n");
196                 ret = -EINVAL;
197                 goto out_free_name;
198         }
199
200         cachep = kmem_cache_create(cache_name, size, 0, 0,
201                                    NULL, NULL);
202         if (!cachep) {
203                 printk("nf_conntrack_register_cache: Can't create slab cache "
204                        "for the features = 0x%x\n", features);
205                 ret = -ENOMEM;
206                 goto out_free_name;
207         }
208
209         write_lock_bh(&nf_ct_cache_lock);
210         nf_ct_cache[features].use = 1;
211         nf_ct_cache[features].size = size;
212         nf_ct_cache[features].cachep = cachep;
213         nf_ct_cache[features].name = cache_name;
214         write_unlock_bh(&nf_ct_cache_lock);
215
216         goto out_up_mutex;
217
218 out_free_name:
219         kfree(cache_name);
220 out_up_mutex:
221         mutex_unlock(&nf_ct_cache_mutex);
222         return ret;
223 }
224 EXPORT_SYMBOL_GPL(nf_conntrack_register_cache);
225
226 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
227 void nf_conntrack_unregister_cache(u_int32_t features)
228 {
229         struct kmem_cache *cachep;
230         char *name;
231
232         /*
233          * This assures that kmem_cache_create() isn't called before destroying
234          * slab cache.
235          */
236         DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features);
237         mutex_lock(&nf_ct_cache_mutex);
238
239         write_lock_bh(&nf_ct_cache_lock);
240         if (--nf_ct_cache[features].use > 0) {
241                 write_unlock_bh(&nf_ct_cache_lock);
242                 mutex_unlock(&nf_ct_cache_mutex);
243                 return;
244         }
245         cachep = nf_ct_cache[features].cachep;
246         name = nf_ct_cache[features].name;
247         nf_ct_cache[features].cachep = NULL;
248         nf_ct_cache[features].name = NULL;
249         nf_ct_cache[features].size = 0;
250         write_unlock_bh(&nf_ct_cache_lock);
251
252         synchronize_net();
253
254         kmem_cache_destroy(cachep);
255         kfree(name);
256
257         mutex_unlock(&nf_ct_cache_mutex);
258 }
259 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_cache);
260
261 int
262 nf_ct_get_tuple(const struct sk_buff *skb,
263                 unsigned int nhoff,
264                 unsigned int dataoff,
265                 u_int16_t l3num,
266                 u_int8_t protonum,
267                 struct nf_conntrack_tuple *tuple,
268                 const struct nf_conntrack_l3proto *l3proto,
269                 const struct nf_conntrack_l4proto *l4proto)
270 {
271         NF_CT_TUPLE_U_BLANK(tuple);
272
273         tuple->src.l3num = l3num;
274         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
275                 return 0;
276
277         tuple->dst.protonum = protonum;
278         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
279
280         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
281 }
282 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
283
284 int
285 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
286                    const struct nf_conntrack_tuple *orig,
287                    const struct nf_conntrack_l3proto *l3proto,
288                    const struct nf_conntrack_l4proto *l4proto)
289 {
290         NF_CT_TUPLE_U_BLANK(inverse);
291
292         inverse->src.l3num = orig->src.l3num;
293         if (l3proto->invert_tuple(inverse, orig) == 0)
294                 return 0;
295
296         inverse->dst.dir = !orig->dst.dir;
297
298         inverse->dst.protonum = orig->dst.protonum;
299         return l4proto->invert_tuple(inverse, orig);
300 }
301 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
302
303 static void
304 clean_from_lists(struct nf_conn *ct)
305 {
306         DEBUGP("clean_from_lists(%p)\n", ct);
307         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
308         list_del(&ct->tuplehash[IP_CT_DIR_REPLY].list);
309
310         /* Destroy all pending expectations */
311         nf_ct_remove_expectations(ct);
312 }
313
314 static void
315 destroy_conntrack(struct nf_conntrack *nfct)
316 {
317         struct nf_conn *ct = (struct nf_conn *)nfct;
318         struct nf_conn_help *help = nfct_help(ct);
319         struct nf_conntrack_l3proto *l3proto;
320         struct nf_conntrack_l4proto *l4proto;
321
322         DEBUGP("destroy_conntrack(%p)\n", ct);
323         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
324         NF_CT_ASSERT(!timer_pending(&ct->timeout));
325
326         nf_conntrack_event(IPCT_DESTROY, ct);
327         set_bit(IPS_DYING_BIT, &ct->status);
328
329         if (help && help->helper && help->helper->destroy)
330                 help->helper->destroy(ct);
331
332         /* To make sure we don't get any weird locking issues here:
333          * destroy_conntrack() MUST NOT be called with a write lock
334          * to nf_conntrack_lock!!! -HW */
335         rcu_read_lock();
336         l3proto = __nf_ct_l3proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num);
337         if (l3proto && l3proto->destroy)
338                 l3proto->destroy(ct);
339
340         l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num,
341                                        ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
342         if (l4proto && l4proto->destroy)
343                 l4proto->destroy(ct);
344         rcu_read_unlock();
345
346         if (nf_conntrack_destroyed)
347                 nf_conntrack_destroyed(ct);
348
349         write_lock_bh(&nf_conntrack_lock);
350         /* Expectations will have been removed in clean_from_lists,
351          * except TFTP can create an expectation on the first packet,
352          * before connection is in the list, so we need to clean here,
353          * too. */
354         nf_ct_remove_expectations(ct);
355
356         /* We overload first tuple to link into unconfirmed list. */
357         if (!nf_ct_is_confirmed(ct)) {
358                 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
359                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
360         }
361
362         NF_CT_STAT_INC(delete);
363         write_unlock_bh(&nf_conntrack_lock);
364
365         if (ct->master)
366                 nf_ct_put(ct->master);
367
368         DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
369         nf_conntrack_free(ct);
370 }
371
372 static void death_by_timeout(unsigned long ul_conntrack)
373 {
374         struct nf_conn *ct = (void *)ul_conntrack;
375
376         write_lock_bh(&nf_conntrack_lock);
377         /* Inside lock so preempt is disabled on module removal path.
378          * Otherwise we can get spurious warnings. */
379         NF_CT_STAT_INC(delete_list);
380         clean_from_lists(ct);
381         write_unlock_bh(&nf_conntrack_lock);
382         nf_ct_put(ct);
383 }
384
385 struct nf_conntrack_tuple_hash *
386 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
387                     const struct nf_conn *ignored_conntrack)
388 {
389         struct nf_conntrack_tuple_hash *h;
390         unsigned int hash = hash_conntrack(tuple);
391
392         list_for_each_entry(h, &nf_conntrack_hash[hash], list) {
393                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
394                     nf_ct_tuple_equal(tuple, &h->tuple)) {
395                         NF_CT_STAT_INC(found);
396                         return h;
397                 }
398                 NF_CT_STAT_INC(searched);
399         }
400
401         return NULL;
402 }
403 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
404
405 /* Find a connection corresponding to a tuple. */
406 struct nf_conntrack_tuple_hash *
407 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple,
408                       const struct nf_conn *ignored_conntrack)
409 {
410         struct nf_conntrack_tuple_hash *h;
411
412         read_lock_bh(&nf_conntrack_lock);
413         h = __nf_conntrack_find(tuple, ignored_conntrack);
414         if (h)
415                 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
416         read_unlock_bh(&nf_conntrack_lock);
417
418         return h;
419 }
420 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
421
422 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
423                                        unsigned int hash,
424                                        unsigned int repl_hash) 
425 {
426         ct->id = ++nf_conntrack_next_id;
427         list_add(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list,
428                  &nf_conntrack_hash[hash]);
429         list_add(&ct->tuplehash[IP_CT_DIR_REPLY].list,
430                  &nf_conntrack_hash[repl_hash]);
431 }
432
433 void nf_conntrack_hash_insert(struct nf_conn *ct)
434 {
435         unsigned int hash, repl_hash;
436
437         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
438         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
439
440         write_lock_bh(&nf_conntrack_lock);
441         __nf_conntrack_hash_insert(ct, hash, repl_hash);
442         write_unlock_bh(&nf_conntrack_lock);
443 }
444 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
445
446 /* Confirm a connection given skb; places it in hash table */
447 int
448 __nf_conntrack_confirm(struct sk_buff **pskb)
449 {
450         unsigned int hash, repl_hash;
451         struct nf_conntrack_tuple_hash *h;
452         struct nf_conn *ct;
453         struct nf_conn_help *help;
454         enum ip_conntrack_info ctinfo;
455
456         ct = nf_ct_get(*pskb, &ctinfo);
457
458         /* ipt_REJECT uses nf_conntrack_attach to attach related
459            ICMP/TCP RST packets in other direction.  Actual packet
460            which created connection will be IP_CT_NEW or for an
461            expected connection, IP_CT_RELATED. */
462         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
463                 return NF_ACCEPT;
464
465         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
466         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
467
468         /* We're not in hash table, and we refuse to set up related
469            connections for unconfirmed conns.  But packet copies and
470            REJECT will give spurious warnings here. */
471         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
472
473         /* No external references means noone else could have
474            confirmed us. */
475         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
476         DEBUGP("Confirming conntrack %p\n", ct);
477
478         write_lock_bh(&nf_conntrack_lock);
479
480         /* See if there's one in the list already, including reverse:
481            NAT could have grabbed it without realizing, since we're
482            not in the hash.  If there is, we lost race. */
483         list_for_each_entry(h, &nf_conntrack_hash[hash], list)
484                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
485                                       &h->tuple))
486                         goto out;
487         list_for_each_entry(h, &nf_conntrack_hash[repl_hash], list)
488                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
489                                       &h->tuple))
490                         goto out;
491
492         /* Remove from unconfirmed list */
493         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
494
495         __nf_conntrack_hash_insert(ct, hash, repl_hash);
496         /* Timer relative to confirmation time, not original
497            setting time, otherwise we'd get timer wrap in
498            weird delay cases. */
499         ct->timeout.expires += jiffies;
500         add_timer(&ct->timeout);
501         atomic_inc(&ct->ct_general.use);
502         set_bit(IPS_CONFIRMED_BIT, &ct->status);
503         NF_CT_STAT_INC(insert);
504         write_unlock_bh(&nf_conntrack_lock);
505         help = nfct_help(ct);
506         if (help && help->helper)
507                 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
508 #ifdef CONFIG_NF_NAT_NEEDED
509         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
510             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
511                 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
512 #endif
513         nf_conntrack_event_cache(master_ct(ct) ?
514                                  IPCT_RELATED : IPCT_NEW, *pskb);
515         return NF_ACCEPT;
516
517 out:
518         NF_CT_STAT_INC(insert_failed);
519         write_unlock_bh(&nf_conntrack_lock);
520         return NF_DROP;
521 }
522 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
523
524 /* Returns true if a connection correspondings to the tuple (required
525    for NAT). */
526 int
527 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
528                          const struct nf_conn *ignored_conntrack)
529 {
530         struct nf_conntrack_tuple_hash *h;
531
532         read_lock_bh(&nf_conntrack_lock);
533         h = __nf_conntrack_find(tuple, ignored_conntrack);
534         read_unlock_bh(&nf_conntrack_lock);
535
536         return h != NULL;
537 }
538 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
539
540 /* There's a small race here where we may free a just-assured
541    connection.  Too bad: we're in trouble anyway. */
542 static int early_drop(struct list_head *chain)
543 {
544         /* Traverse backwards: gives us oldest, which is roughly LRU */
545         struct nf_conntrack_tuple_hash *h;
546         struct nf_conn *ct = NULL, *tmp;
547         int dropped = 0;
548
549         read_lock_bh(&nf_conntrack_lock);
550         list_for_each_entry_reverse(h, chain, list) {
551                 tmp = nf_ct_tuplehash_to_ctrack(h);
552                 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) {
553                         ct = tmp;
554                         atomic_inc(&ct->ct_general.use);
555                         break;
556                 }
557         }
558         read_unlock_bh(&nf_conntrack_lock);
559
560         if (!ct)
561                 return dropped;
562
563         if (del_timer(&ct->timeout)) {
564                 death_by_timeout((unsigned long)ct);
565                 dropped = 1;
566                 NF_CT_STAT_INC(early_drop);
567         }
568         nf_ct_put(ct);
569         return dropped;
570 }
571
572 static struct nf_conn *
573 __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
574                      const struct nf_conntrack_tuple *repl,
575                      const struct nf_conntrack_l3proto *l3proto,
576                      u_int32_t features)
577 {
578         struct nf_conn *conntrack = NULL;
579         struct nf_conntrack_helper *helper;
580
581         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
582                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
583                 nf_conntrack_hash_rnd_initted = 1;
584         }
585
586         /* We don't want any race condition at early drop stage */
587         atomic_inc(&nf_conntrack_count);
588
589         if (nf_conntrack_max
590             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
591                 unsigned int hash = hash_conntrack(orig);
592                 /* Try dropping from this hash chain. */
593                 if (!early_drop(&nf_conntrack_hash[hash])) {
594                         atomic_dec(&nf_conntrack_count);
595                         if (net_ratelimit())
596                                 printk(KERN_WARNING
597                                        "nf_conntrack: table full, dropping"
598                                        " packet.\n");
599                         return ERR_PTR(-ENOMEM);
600                 }
601         }
602
603         /*  find features needed by this conntrack. */
604         features |= l3proto->get_features(orig);
605
606         /* FIXME: protect helper list per RCU */
607         read_lock_bh(&nf_conntrack_lock);
608         helper = __nf_ct_helper_find(repl);
609         /* NAT might want to assign a helper later */
610         if (helper || features & NF_CT_F_NAT)
611                 features |= NF_CT_F_HELP;
612         read_unlock_bh(&nf_conntrack_lock);
613
614         DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
615
616         read_lock_bh(&nf_ct_cache_lock);
617
618         if (unlikely(!nf_ct_cache[features].use)) {
619                 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
620                         features);
621                 goto out;
622         }
623
624         conntrack = kmem_cache_alloc(nf_ct_cache[features].cachep, GFP_ATOMIC);
625         if (conntrack == NULL) {
626                 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
627                 goto out;
628         }
629
630         memset(conntrack, 0, nf_ct_cache[features].size);
631         conntrack->features = features;
632         atomic_set(&conntrack->ct_general.use, 1);
633         conntrack->ct_general.destroy = destroy_conntrack;
634         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
635         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
636         /* Don't set timer yet: wait for confirmation */
637         init_timer(&conntrack->timeout);
638         conntrack->timeout.data = (unsigned long)conntrack;
639         conntrack->timeout.function = death_by_timeout;
640         read_unlock_bh(&nf_ct_cache_lock);
641
642         return conntrack;
643 out:
644         read_unlock_bh(&nf_ct_cache_lock);
645         atomic_dec(&nf_conntrack_count);
646         return conntrack;
647 }
648
649 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
650                                    const struct nf_conntrack_tuple *repl)
651 {
652         struct nf_conntrack_l3proto *l3proto;
653         struct nf_conn *ct;
654
655         rcu_read_lock();
656         l3proto = __nf_ct_l3proto_find(orig->src.l3num);
657         ct = __nf_conntrack_alloc(orig, repl, l3proto, 0);
658         rcu_read_unlock();
659
660         return ct;
661 }
662 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
663
664 void nf_conntrack_free(struct nf_conn *conntrack)
665 {
666         u_int32_t features = conntrack->features;
667         NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
668         DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
669                conntrack);
670         kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
671         atomic_dec(&nf_conntrack_count);
672 }
673 EXPORT_SYMBOL_GPL(nf_conntrack_free);
674
675 /* Allocate a new conntrack: we return -ENOMEM if classification
676    failed due to stress.  Otherwise it really is unclassifiable. */
677 static struct nf_conntrack_tuple_hash *
678 init_conntrack(const struct nf_conntrack_tuple *tuple,
679                struct nf_conntrack_l3proto *l3proto,
680                struct nf_conntrack_l4proto *l4proto,
681                struct sk_buff *skb,
682                unsigned int dataoff)
683 {
684         struct nf_conn *conntrack;
685         struct nf_conntrack_tuple repl_tuple;
686         struct nf_conntrack_expect *exp;
687         u_int32_t features = 0;
688
689         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
690                 DEBUGP("Can't invert tuple.\n");
691                 return NULL;
692         }
693
694         read_lock_bh(&nf_conntrack_lock);
695         exp = __nf_conntrack_expect_find(tuple);
696         if (exp && exp->helper)
697                 features = NF_CT_F_HELP;
698         read_unlock_bh(&nf_conntrack_lock);
699
700         conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto, features);
701         if (conntrack == NULL || IS_ERR(conntrack)) {
702                 DEBUGP("Can't allocate conntrack.\n");
703                 return (struct nf_conntrack_tuple_hash *)conntrack;
704         }
705
706         if (!l4proto->new(conntrack, skb, dataoff)) {
707                 nf_conntrack_free(conntrack);
708                 DEBUGP("init conntrack: can't track with proto module\n");
709                 return NULL;
710         }
711
712         write_lock_bh(&nf_conntrack_lock);
713         exp = find_expectation(tuple);
714
715         if (exp) {
716                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
717                         conntrack, exp);
718                 /* Welcome, Mr. Bond.  We've been expecting you... */
719                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
720                 conntrack->master = exp->master;
721                 if (exp->helper)
722                         nfct_help(conntrack)->helper = exp->helper;
723 #ifdef CONFIG_NF_CONNTRACK_MARK
724                 conntrack->mark = exp->master->mark;
725 #endif
726 #ifdef CONFIG_NF_CONNTRACK_SECMARK
727                 conntrack->secmark = exp->master->secmark;
728 #endif
729                 nf_conntrack_get(&conntrack->master->ct_general);
730                 NF_CT_STAT_INC(expect_new);
731         } else {
732                 struct nf_conn_help *help = nfct_help(conntrack);
733
734                 if (help)
735                         help->helper = __nf_ct_helper_find(&repl_tuple);
736                 NF_CT_STAT_INC(new);
737         }
738
739         /* Overload tuple linked list to put us in unconfirmed list. */
740         list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
741
742         write_unlock_bh(&nf_conntrack_lock);
743
744         if (exp) {
745                 if (exp->expectfn)
746                         exp->expectfn(conntrack, exp);
747                 nf_conntrack_expect_put(exp);
748         }
749
750         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
751 }
752
753 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
754 static inline struct nf_conn *
755 resolve_normal_ct(struct sk_buff *skb,
756                   unsigned int dataoff,
757                   u_int16_t l3num,
758                   u_int8_t protonum,
759                   struct nf_conntrack_l3proto *l3proto,
760                   struct nf_conntrack_l4proto *l4proto,
761                   int *set_reply,
762                   enum ip_conntrack_info *ctinfo)
763 {
764         struct nf_conntrack_tuple tuple;
765         struct nf_conntrack_tuple_hash *h;
766         struct nf_conn *ct;
767
768         if (!nf_ct_get_tuple(skb, (unsigned int)(skb->nh.raw - skb->data),
769                              dataoff, l3num, protonum, &tuple, l3proto,
770                              l4proto)) {
771                 DEBUGP("resolve_normal_ct: Can't get tuple\n");
772                 return NULL;
773         }
774
775         /* look for tuple match */
776         h = nf_conntrack_find_get(&tuple, NULL);
777         if (!h) {
778                 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
779                 if (!h)
780                         return NULL;
781                 if (IS_ERR(h))
782                         return (void *)h;
783         }
784         ct = nf_ct_tuplehash_to_ctrack(h);
785
786         /* It exists; we have (non-exclusive) reference. */
787         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
788                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
789                 /* Please set reply bit if this packet OK */
790                 *set_reply = 1;
791         } else {
792                 /* Once we've had two way comms, always ESTABLISHED. */
793                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
794                         DEBUGP("nf_conntrack_in: normal packet for %p\n", ct);
795                         *ctinfo = IP_CT_ESTABLISHED;
796                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
797                         DEBUGP("nf_conntrack_in: related packet for %p\n", ct);
798                         *ctinfo = IP_CT_RELATED;
799                 } else {
800                         DEBUGP("nf_conntrack_in: new packet for %p\n", ct);
801                         *ctinfo = IP_CT_NEW;
802                 }
803                 *set_reply = 0;
804         }
805         skb->nfct = &ct->ct_general;
806         skb->nfctinfo = *ctinfo;
807         return ct;
808 }
809
810 unsigned int
811 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
812 {
813         struct nf_conn *ct;
814         enum ip_conntrack_info ctinfo;
815         struct nf_conntrack_l3proto *l3proto;
816         struct nf_conntrack_l4proto *l4proto;
817         unsigned int dataoff;
818         u_int8_t protonum;
819         int set_reply = 0;
820         int ret;
821
822         /* Previously seen (loopback or untracked)?  Ignore. */
823         if ((*pskb)->nfct) {
824                 NF_CT_STAT_INC(ignore);
825                 return NF_ACCEPT;
826         }
827
828         /* rcu_read_lock()ed by nf_hook_slow */
829         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
830
831         if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) {
832                 DEBUGP("not prepared to track yet or error occured\n");
833                 return -ret;
834         }
835
836         l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
837
838         /* It may be an special packet, error, unclean...
839          * inverse of the return code tells to the netfilter
840          * core what to do with the packet. */
841         if (l4proto->error != NULL &&
842             (ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
843                 NF_CT_STAT_INC(error);
844                 NF_CT_STAT_INC(invalid);
845                 return -ret;
846         }
847
848         ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, l4proto,
849                                &set_reply, &ctinfo);
850         if (!ct) {
851                 /* Not valid part of a connection */
852                 NF_CT_STAT_INC(invalid);
853                 return NF_ACCEPT;
854         }
855
856         if (IS_ERR(ct)) {
857                 /* Too stressed to deal. */
858                 NF_CT_STAT_INC(drop);
859                 return NF_DROP;
860         }
861
862         NF_CT_ASSERT((*pskb)->nfct);
863
864         ret = l4proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
865         if (ret < 0) {
866                 /* Invalid: inverse of the return code tells
867                  * the netfilter core what to do */
868                 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
869                 nf_conntrack_put((*pskb)->nfct);
870                 (*pskb)->nfct = NULL;
871                 NF_CT_STAT_INC(invalid);
872                 return -ret;
873         }
874
875         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
876                 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
877
878         return ret;
879 }
880 EXPORT_SYMBOL_GPL(nf_conntrack_in);
881
882 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
883                          const struct nf_conntrack_tuple *orig)
884 {
885         int ret;
886
887         rcu_read_lock();
888         ret = nf_ct_invert_tuple(inverse, orig,
889                                  __nf_ct_l3proto_find(orig->src.l3num),
890                                  __nf_ct_l4proto_find(orig->src.l3num,
891                                                       orig->dst.protonum));
892         rcu_read_unlock();
893         return ret;
894 }
895 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
896
897 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
898    implicitly racy: see __nf_conntrack_confirm */
899 void nf_conntrack_alter_reply(struct nf_conn *ct,
900                               const struct nf_conntrack_tuple *newreply)
901 {
902         struct nf_conn_help *help = nfct_help(ct);
903
904         write_lock_bh(&nf_conntrack_lock);
905         /* Should be unconfirmed, so not in hash table yet */
906         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
907
908         DEBUGP("Altering reply tuple of %p to ", ct);
909         NF_CT_DUMP_TUPLE(newreply);
910
911         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
912         if (!ct->master && help && help->expecting == 0)
913                 help->helper = __nf_ct_helper_find(newreply);
914         write_unlock_bh(&nf_conntrack_lock);
915 }
916 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
917
918 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
919 void __nf_ct_refresh_acct(struct nf_conn *ct,
920                           enum ip_conntrack_info ctinfo,
921                           const struct sk_buff *skb,
922                           unsigned long extra_jiffies,
923                           int do_acct)
924 {
925         int event = 0;
926
927         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
928         NF_CT_ASSERT(skb);
929
930         write_lock_bh(&nf_conntrack_lock);
931
932         /* Only update if this is not a fixed timeout */
933         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
934                 write_unlock_bh(&nf_conntrack_lock);
935                 return;
936         }
937
938         /* If not in hash table, timer will not be active yet */
939         if (!nf_ct_is_confirmed(ct)) {
940                 ct->timeout.expires = extra_jiffies;
941                 event = IPCT_REFRESH;
942         } else {
943                 unsigned long newtime = jiffies + extra_jiffies;
944
945                 /* Only update the timeout if the new timeout is at least
946                    HZ jiffies from the old timeout. Need del_timer for race
947                    avoidance (may already be dying). */
948                 if (newtime - ct->timeout.expires >= HZ
949                     && del_timer(&ct->timeout)) {
950                         ct->timeout.expires = newtime;
951                         add_timer(&ct->timeout);
952                         event = IPCT_REFRESH;
953                 }
954         }
955
956 #ifdef CONFIG_NF_CT_ACCT
957         if (do_acct) {
958                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
959                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
960                         skb->len - (unsigned int)(skb->nh.raw - skb->data);
961
962                 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
963                     || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
964                         event |= IPCT_COUNTER_FILLING;
965         }
966 #endif
967
968         write_unlock_bh(&nf_conntrack_lock);
969
970         /* must be unlocked when calling event cache */
971         if (event)
972                 nf_conntrack_event_cache(event, skb);
973 }
974 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
975
976 #if defined(CONFIG_NF_CT_NETLINK) || \
977     defined(CONFIG_NF_CT_NETLINK_MODULE)
978
979 #include <linux/netfilter/nfnetlink.h>
980 #include <linux/netfilter/nfnetlink_conntrack.h>
981 #include <linux/mutex.h>
982
983
984 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
985  * in ip_conntrack_core, since we don't want the protocols to autoload
986  * or depend on ctnetlink */
987 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
988                                const struct nf_conntrack_tuple *tuple)
989 {
990         NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
991                 &tuple->src.u.tcp.port);
992         NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
993                 &tuple->dst.u.tcp.port);
994         return 0;
995
996 nfattr_failure:
997         return -1;
998 }
999 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr);
1000
1001 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
1002         [CTA_PROTO_SRC_PORT-1]  = sizeof(u_int16_t),
1003         [CTA_PROTO_DST_PORT-1]  = sizeof(u_int16_t)
1004 };
1005
1006 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
1007                                struct nf_conntrack_tuple *t)
1008 {
1009         if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
1010                 return -EINVAL;
1011
1012         if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
1013                 return -EINVAL;
1014
1015         t->src.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
1016         t->dst.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
1017
1018         return 0;
1019 }
1020 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple);
1021 #endif
1022
1023 /* Used by ipt_REJECT and ip6t_REJECT. */
1024 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1025 {
1026         struct nf_conn *ct;
1027         enum ip_conntrack_info ctinfo;
1028
1029         /* This ICMP is in reverse direction to the packet which caused it */
1030         ct = nf_ct_get(skb, &ctinfo);
1031         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1032                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
1033         else
1034                 ctinfo = IP_CT_RELATED;
1035
1036         /* Attach to new skbuff, and increment count */
1037         nskb->nfct = &ct->ct_general;
1038         nskb->nfctinfo = ctinfo;
1039         nf_conntrack_get(nskb->nfct);
1040 }
1041 EXPORT_SYMBOL_GPL(__nf_conntrack_attach);
1042
1043 static inline int
1044 do_iter(const struct nf_conntrack_tuple_hash *i,
1045         int (*iter)(struct nf_conn *i, void *data),
1046         void *data)
1047 {
1048         return iter(nf_ct_tuplehash_to_ctrack(i), data);
1049 }
1050
1051 /* Bring out ya dead! */
1052 static struct nf_conn *
1053 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
1054                 void *data, unsigned int *bucket)
1055 {
1056         struct nf_conntrack_tuple_hash *h;
1057         struct nf_conn *ct;
1058
1059         write_lock_bh(&nf_conntrack_lock);
1060         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1061                 list_for_each_entry(h, &nf_conntrack_hash[*bucket], list) {
1062                         ct = nf_ct_tuplehash_to_ctrack(h);
1063                         if (iter(ct, data))
1064                                 goto found;
1065                 }
1066         }
1067         list_for_each_entry(h, &unconfirmed, list) {
1068                 ct = nf_ct_tuplehash_to_ctrack(h);
1069                 if (iter(ct, data))
1070                         goto found;
1071         }
1072         write_unlock_bh(&nf_conntrack_lock);
1073         return NULL;
1074 found:
1075         atomic_inc(&ct->ct_general.use);
1076         write_unlock_bh(&nf_conntrack_lock);
1077         return ct;
1078 }
1079
1080 void
1081 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
1082 {
1083         struct nf_conn *ct;
1084         unsigned int bucket = 0;
1085
1086         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1087                 /* Time to push up daises... */
1088                 if (del_timer(&ct->timeout))
1089                         death_by_timeout((unsigned long)ct);
1090                 /* ... else the timer will get him soon. */
1091
1092                 nf_ct_put(ct);
1093         }
1094 }
1095 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1096
1097 static int kill_all(struct nf_conn *i, void *data)
1098 {
1099         return 1;
1100 }
1101
1102 static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
1103 {
1104         if (vmalloced)
1105                 vfree(hash);
1106         else
1107                 free_pages((unsigned long)hash, 
1108                            get_order(sizeof(struct list_head) * size));
1109 }
1110
1111 void nf_conntrack_flush(void)
1112 {
1113         nf_ct_iterate_cleanup(kill_all, NULL);
1114 }
1115 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1116
1117 /* Mishearing the voices in his head, our hero wonders how he's
1118    supposed to kill the mall. */
1119 void nf_conntrack_cleanup(void)
1120 {
1121         int i;
1122
1123         rcu_assign_pointer(ip_ct_attach, NULL);
1124
1125         /* This makes sure all current packets have passed through
1126            netfilter framework.  Roll on, two-stage module
1127            delete... */
1128         synchronize_net();
1129
1130         nf_ct_event_cache_flush();
1131  i_see_dead_people:
1132         nf_conntrack_flush();
1133         if (atomic_read(&nf_conntrack_count) != 0) {
1134                 schedule();
1135                 goto i_see_dead_people;
1136         }
1137         /* wait until all references to nf_conntrack_untracked are dropped */
1138         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1139                 schedule();
1140
1141         for (i = 0; i < NF_CT_F_NUM; i++) {
1142                 if (nf_ct_cache[i].use == 0)
1143                         continue;
1144
1145                 NF_CT_ASSERT(nf_ct_cache[i].use == 1);
1146                 nf_ct_cache[i].use = 1;
1147                 nf_conntrack_unregister_cache(i);
1148         }
1149         kmem_cache_destroy(nf_conntrack_expect_cachep);
1150         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1151                             nf_conntrack_htable_size);
1152
1153         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_generic);
1154
1155         /* free l3proto protocol tables */
1156         for (i = 0; i < PF_MAX; i++)
1157                 if (nf_ct_protos[i]) {
1158                         kfree(nf_ct_protos[i]);
1159                         nf_ct_protos[i] = NULL;
1160                 }
1161 }
1162
1163 static struct list_head *alloc_hashtable(int size, int *vmalloced)
1164 {
1165         struct list_head *hash;
1166         unsigned int i;
1167
1168         *vmalloced = 0; 
1169         hash = (void*)__get_free_pages(GFP_KERNEL, 
1170                                        get_order(sizeof(struct list_head)
1171                                                  * size));
1172         if (!hash) { 
1173                 *vmalloced = 1;
1174                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1175                 hash = vmalloc(sizeof(struct list_head) * size);
1176         }
1177
1178         if (hash)
1179                 for (i = 0; i < size; i++) 
1180                         INIT_LIST_HEAD(&hash[i]);
1181
1182         return hash;
1183 }
1184
1185 int set_hashsize(const char *val, struct kernel_param *kp)
1186 {
1187         int i, bucket, hashsize, vmalloced;
1188         int old_vmalloced, old_size;
1189         int rnd;
1190         struct list_head *hash, *old_hash;
1191         struct nf_conntrack_tuple_hash *h;
1192
1193         /* On boot, we can set this without any fancy locking. */
1194         if (!nf_conntrack_htable_size)
1195                 return param_set_uint(val, kp);
1196
1197         hashsize = simple_strtol(val, NULL, 0);
1198         if (!hashsize)
1199                 return -EINVAL;
1200
1201         hash = alloc_hashtable(hashsize, &vmalloced);
1202         if (!hash)
1203                 return -ENOMEM;
1204
1205         /* We have to rehahs for the new table anyway, so we also can
1206          * use a newrandom seed */
1207         get_random_bytes(&rnd, 4);
1208
1209         write_lock_bh(&nf_conntrack_lock);
1210         for (i = 0; i < nf_conntrack_htable_size; i++) {
1211                 while (!list_empty(&nf_conntrack_hash[i])) {
1212                         h = list_entry(nf_conntrack_hash[i].next,
1213                                        struct nf_conntrack_tuple_hash, list);
1214                         list_del(&h->list);
1215                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1216                         list_add_tail(&h->list, &hash[bucket]);
1217                 }
1218         }
1219         old_size = nf_conntrack_htable_size;
1220         old_vmalloced = nf_conntrack_vmalloc;
1221         old_hash = nf_conntrack_hash;
1222
1223         nf_conntrack_htable_size = hashsize;
1224         nf_conntrack_vmalloc = vmalloced;
1225         nf_conntrack_hash = hash;
1226         nf_conntrack_hash_rnd = rnd;
1227         write_unlock_bh(&nf_conntrack_lock);
1228
1229         free_conntrack_hash(old_hash, old_vmalloced, old_size);
1230         return 0;
1231 }
1232
1233 module_param_call(hashsize, set_hashsize, param_get_uint,
1234                   &nf_conntrack_htable_size, 0600);
1235
1236 int __init nf_conntrack_init(void)
1237 {
1238         unsigned int i;
1239         int ret;
1240
1241         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1242          * machine has 256 buckets.  >= 1GB machines have 8192 buckets. */
1243         if (!nf_conntrack_htable_size) {
1244                 nf_conntrack_htable_size
1245                         = (((num_physpages << PAGE_SHIFT) / 16384)
1246                            / sizeof(struct list_head));
1247                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1248                         nf_conntrack_htable_size = 8192;
1249                 if (nf_conntrack_htable_size < 16)
1250                         nf_conntrack_htable_size = 16;
1251         }
1252         nf_conntrack_max = 8 * nf_conntrack_htable_size;
1253
1254         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1255                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1256                nf_conntrack_max);
1257
1258         nf_conntrack_hash = alloc_hashtable(nf_conntrack_htable_size,
1259                                             &nf_conntrack_vmalloc);
1260         if (!nf_conntrack_hash) {
1261                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1262                 goto err_out;
1263         }
1264
1265         ret = nf_conntrack_register_cache(NF_CT_F_BASIC, "nf_conntrack:basic",
1266                                           sizeof(struct nf_conn));
1267         if (ret < 0) {
1268                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1269                 goto err_free_hash;
1270         }
1271
1272         nf_conntrack_expect_cachep = kmem_cache_create("nf_conntrack_expect",
1273                                         sizeof(struct nf_conntrack_expect),
1274                                         0, 0, NULL, NULL);
1275         if (!nf_conntrack_expect_cachep) {
1276                 printk(KERN_ERR "Unable to create nf_expect slab cache\n");
1277                 goto err_free_conntrack_slab;
1278         }
1279
1280         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_generic);
1281         if (ret < 0)
1282                 goto out_free_expect_slab;
1283
1284         /* Don't NEED lock here, but good form anyway. */
1285         write_lock_bh(&nf_conntrack_lock);
1286         for (i = 0; i < AF_MAX; i++)
1287                 nf_ct_l3protos[i] = &nf_conntrack_l3proto_generic;
1288         write_unlock_bh(&nf_conntrack_lock);
1289
1290         /* For use by REJECT target */
1291         rcu_assign_pointer(ip_ct_attach, __nf_conntrack_attach);
1292
1293         /* Set up fake conntrack:
1294             - to never be deleted, not in any hashes */
1295         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1296         /*  - and look it like as a confirmed connection */
1297         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1298
1299         return ret;
1300
1301 out_free_expect_slab:
1302         kmem_cache_destroy(nf_conntrack_expect_cachep);
1303 err_free_conntrack_slab:
1304         nf_conntrack_unregister_cache(NF_CT_F_BASIC);
1305 err_free_hash:
1306         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1307                             nf_conntrack_htable_size);
1308 err_out:
1309         return -ENOMEM;
1310 }