4fdf4849baf84c387242f606457c087205b305a9
[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         typeof(nf_conntrack_destroyed) destroyed;
322
323         DEBUGP("destroy_conntrack(%p)\n", ct);
324         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
325         NF_CT_ASSERT(!timer_pending(&ct->timeout));
326
327         nf_conntrack_event(IPCT_DESTROY, ct);
328         set_bit(IPS_DYING_BIT, &ct->status);
329
330         if (help && help->helper && help->helper->destroy)
331                 help->helper->destroy(ct);
332
333         /* To make sure we don't get any weird locking issues here:
334          * destroy_conntrack() MUST NOT be called with a write lock
335          * to nf_conntrack_lock!!! -HW */
336         rcu_read_lock();
337         l3proto = __nf_ct_l3proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num);
338         if (l3proto && l3proto->destroy)
339                 l3proto->destroy(ct);
340
341         l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num,
342                                        ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
343         if (l4proto && l4proto->destroy)
344                 l4proto->destroy(ct);
345
346         destroyed = rcu_dereference(nf_conntrack_destroyed);
347         if (destroyed)
348                 destroyed(ct);
349
350         rcu_read_unlock();
351
352         write_lock_bh(&nf_conntrack_lock);
353         /* Expectations will have been removed in clean_from_lists,
354          * except TFTP can create an expectation on the first packet,
355          * before connection is in the list, so we need to clean here,
356          * too. */
357         nf_ct_remove_expectations(ct);
358
359         /* We overload first tuple to link into unconfirmed list. */
360         if (!nf_ct_is_confirmed(ct)) {
361                 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
362                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
363         }
364
365         NF_CT_STAT_INC(delete);
366         write_unlock_bh(&nf_conntrack_lock);
367
368         if (ct->master)
369                 nf_ct_put(ct->master);
370
371         DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
372         nf_conntrack_free(ct);
373 }
374
375 static void death_by_timeout(unsigned long ul_conntrack)
376 {
377         struct nf_conn *ct = (void *)ul_conntrack;
378
379         write_lock_bh(&nf_conntrack_lock);
380         /* Inside lock so preempt is disabled on module removal path.
381          * Otherwise we can get spurious warnings. */
382         NF_CT_STAT_INC(delete_list);
383         clean_from_lists(ct);
384         write_unlock_bh(&nf_conntrack_lock);
385         nf_ct_put(ct);
386 }
387
388 struct nf_conntrack_tuple_hash *
389 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
390                     const struct nf_conn *ignored_conntrack)
391 {
392         struct nf_conntrack_tuple_hash *h;
393         unsigned int hash = hash_conntrack(tuple);
394
395         list_for_each_entry(h, &nf_conntrack_hash[hash], list) {
396                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
397                     nf_ct_tuple_equal(tuple, &h->tuple)) {
398                         NF_CT_STAT_INC(found);
399                         return h;
400                 }
401                 NF_CT_STAT_INC(searched);
402         }
403
404         return NULL;
405 }
406 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
407
408 /* Find a connection corresponding to a tuple. */
409 struct nf_conntrack_tuple_hash *
410 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple,
411                       const struct nf_conn *ignored_conntrack)
412 {
413         struct nf_conntrack_tuple_hash *h;
414
415         read_lock_bh(&nf_conntrack_lock);
416         h = __nf_conntrack_find(tuple, ignored_conntrack);
417         if (h)
418                 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
419         read_unlock_bh(&nf_conntrack_lock);
420
421         return h;
422 }
423 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
424
425 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
426                                        unsigned int hash,
427                                        unsigned int repl_hash)
428 {
429         ct->id = ++nf_conntrack_next_id;
430         list_add(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list,
431                  &nf_conntrack_hash[hash]);
432         list_add(&ct->tuplehash[IP_CT_DIR_REPLY].list,
433                  &nf_conntrack_hash[repl_hash]);
434 }
435
436 void nf_conntrack_hash_insert(struct nf_conn *ct)
437 {
438         unsigned int hash, repl_hash;
439
440         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
441         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
442
443         write_lock_bh(&nf_conntrack_lock);
444         __nf_conntrack_hash_insert(ct, hash, repl_hash);
445         write_unlock_bh(&nf_conntrack_lock);
446 }
447 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
448
449 /* Confirm a connection given skb; places it in hash table */
450 int
451 __nf_conntrack_confirm(struct sk_buff **pskb)
452 {
453         unsigned int hash, repl_hash;
454         struct nf_conntrack_tuple_hash *h;
455         struct nf_conn *ct;
456         struct nf_conn_help *help;
457         enum ip_conntrack_info ctinfo;
458
459         ct = nf_ct_get(*pskb, &ctinfo);
460
461         /* ipt_REJECT uses nf_conntrack_attach to attach related
462            ICMP/TCP RST packets in other direction.  Actual packet
463            which created connection will be IP_CT_NEW or for an
464            expected connection, IP_CT_RELATED. */
465         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
466                 return NF_ACCEPT;
467
468         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
469         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
470
471         /* We're not in hash table, and we refuse to set up related
472            connections for unconfirmed conns.  But packet copies and
473            REJECT will give spurious warnings here. */
474         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
475
476         /* No external references means noone else could have
477            confirmed us. */
478         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
479         DEBUGP("Confirming conntrack %p\n", ct);
480
481         write_lock_bh(&nf_conntrack_lock);
482
483         /* See if there's one in the list already, including reverse:
484            NAT could have grabbed it without realizing, since we're
485            not in the hash.  If there is, we lost race. */
486         list_for_each_entry(h, &nf_conntrack_hash[hash], list)
487                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
488                                       &h->tuple))
489                         goto out;
490         list_for_each_entry(h, &nf_conntrack_hash[repl_hash], list)
491                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
492                                       &h->tuple))
493                         goto out;
494
495         /* Remove from unconfirmed list */
496         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
497
498         __nf_conntrack_hash_insert(ct, hash, repl_hash);
499         /* Timer relative to confirmation time, not original
500            setting time, otherwise we'd get timer wrap in
501            weird delay cases. */
502         ct->timeout.expires += jiffies;
503         add_timer(&ct->timeout);
504         atomic_inc(&ct->ct_general.use);
505         set_bit(IPS_CONFIRMED_BIT, &ct->status);
506         NF_CT_STAT_INC(insert);
507         write_unlock_bh(&nf_conntrack_lock);
508         help = nfct_help(ct);
509         if (help && help->helper)
510                 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
511 #ifdef CONFIG_NF_NAT_NEEDED
512         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
513             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
514                 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
515 #endif
516         nf_conntrack_event_cache(master_ct(ct) ?
517                                  IPCT_RELATED : IPCT_NEW, *pskb);
518         return NF_ACCEPT;
519
520 out:
521         NF_CT_STAT_INC(insert_failed);
522         write_unlock_bh(&nf_conntrack_lock);
523         return NF_DROP;
524 }
525 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
526
527 /* Returns true if a connection correspondings to the tuple (required
528    for NAT). */
529 int
530 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
531                          const struct nf_conn *ignored_conntrack)
532 {
533         struct nf_conntrack_tuple_hash *h;
534
535         read_lock_bh(&nf_conntrack_lock);
536         h = __nf_conntrack_find(tuple, ignored_conntrack);
537         read_unlock_bh(&nf_conntrack_lock);
538
539         return h != NULL;
540 }
541 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
542
543 /* There's a small race here where we may free a just-assured
544    connection.  Too bad: we're in trouble anyway. */
545 static int early_drop(struct list_head *chain)
546 {
547         /* Traverse backwards: gives us oldest, which is roughly LRU */
548         struct nf_conntrack_tuple_hash *h;
549         struct nf_conn *ct = NULL, *tmp;
550         int dropped = 0;
551
552         read_lock_bh(&nf_conntrack_lock);
553         list_for_each_entry_reverse(h, chain, list) {
554                 tmp = nf_ct_tuplehash_to_ctrack(h);
555                 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) {
556                         ct = tmp;
557                         atomic_inc(&ct->ct_general.use);
558                         break;
559                 }
560         }
561         read_unlock_bh(&nf_conntrack_lock);
562
563         if (!ct)
564                 return dropped;
565
566         if (del_timer(&ct->timeout)) {
567                 death_by_timeout((unsigned long)ct);
568                 dropped = 1;
569                 NF_CT_STAT_INC_ATOMIC(early_drop);
570         }
571         nf_ct_put(ct);
572         return dropped;
573 }
574
575 static struct nf_conn *
576 __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
577                      const struct nf_conntrack_tuple *repl,
578                      const struct nf_conntrack_l3proto *l3proto,
579                      u_int32_t features)
580 {
581         struct nf_conn *conntrack = NULL;
582         struct nf_conntrack_helper *helper;
583
584         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
585                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
586                 nf_conntrack_hash_rnd_initted = 1;
587         }
588
589         /* We don't want any race condition at early drop stage */
590         atomic_inc(&nf_conntrack_count);
591
592         if (nf_conntrack_max
593             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
594                 unsigned int hash = hash_conntrack(orig);
595                 /* Try dropping from this hash chain. */
596                 if (!early_drop(&nf_conntrack_hash[hash])) {
597                         atomic_dec(&nf_conntrack_count);
598                         if (net_ratelimit())
599                                 printk(KERN_WARNING
600                                        "nf_conntrack: table full, dropping"
601                                        " packet.\n");
602                         return ERR_PTR(-ENOMEM);
603                 }
604         }
605
606         /*  find features needed by this conntrack. */
607         features |= l3proto->get_features(orig);
608
609         /* FIXME: protect helper list per RCU */
610         read_lock_bh(&nf_conntrack_lock);
611         helper = __nf_ct_helper_find(repl);
612         /* NAT might want to assign a helper later */
613         if (helper || features & NF_CT_F_NAT)
614                 features |= NF_CT_F_HELP;
615         read_unlock_bh(&nf_conntrack_lock);
616
617         DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
618
619         read_lock_bh(&nf_ct_cache_lock);
620
621         if (unlikely(!nf_ct_cache[features].use)) {
622                 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
623                         features);
624                 goto out;
625         }
626
627         conntrack = kmem_cache_alloc(nf_ct_cache[features].cachep, GFP_ATOMIC);
628         if (conntrack == NULL) {
629                 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
630                 goto out;
631         }
632
633         memset(conntrack, 0, nf_ct_cache[features].size);
634         conntrack->features = features;
635         atomic_set(&conntrack->ct_general.use, 1);
636         conntrack->ct_general.destroy = destroy_conntrack;
637         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
638         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
639         /* Don't set timer yet: wait for confirmation */
640         init_timer(&conntrack->timeout);
641         conntrack->timeout.data = (unsigned long)conntrack;
642         conntrack->timeout.function = death_by_timeout;
643         read_unlock_bh(&nf_ct_cache_lock);
644
645         return conntrack;
646 out:
647         read_unlock_bh(&nf_ct_cache_lock);
648         atomic_dec(&nf_conntrack_count);
649         return conntrack;
650 }
651
652 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
653                                    const struct nf_conntrack_tuple *repl)
654 {
655         struct nf_conntrack_l3proto *l3proto;
656         struct nf_conn *ct;
657
658         rcu_read_lock();
659         l3proto = __nf_ct_l3proto_find(orig->src.l3num);
660         ct = __nf_conntrack_alloc(orig, repl, l3proto, 0);
661         rcu_read_unlock();
662
663         return ct;
664 }
665 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
666
667 void nf_conntrack_free(struct nf_conn *conntrack)
668 {
669         u_int32_t features = conntrack->features;
670         NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
671         DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
672                conntrack);
673         kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
674         atomic_dec(&nf_conntrack_count);
675 }
676 EXPORT_SYMBOL_GPL(nf_conntrack_free);
677
678 /* Allocate a new conntrack: we return -ENOMEM if classification
679    failed due to stress.  Otherwise it really is unclassifiable. */
680 static struct nf_conntrack_tuple_hash *
681 init_conntrack(const struct nf_conntrack_tuple *tuple,
682                struct nf_conntrack_l3proto *l3proto,
683                struct nf_conntrack_l4proto *l4proto,
684                struct sk_buff *skb,
685                unsigned int dataoff)
686 {
687         struct nf_conn *conntrack;
688         struct nf_conntrack_tuple repl_tuple;
689         struct nf_conntrack_expect *exp;
690         u_int32_t features = 0;
691
692         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
693                 DEBUGP("Can't invert tuple.\n");
694                 return NULL;
695         }
696
697         read_lock_bh(&nf_conntrack_lock);
698         exp = __nf_conntrack_expect_find(tuple);
699         if (exp && exp->helper)
700                 features = NF_CT_F_HELP;
701         read_unlock_bh(&nf_conntrack_lock);
702
703         conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto, features);
704         if (conntrack == NULL || IS_ERR(conntrack)) {
705                 DEBUGP("Can't allocate conntrack.\n");
706                 return (struct nf_conntrack_tuple_hash *)conntrack;
707         }
708
709         if (!l4proto->new(conntrack, skb, dataoff)) {
710                 nf_conntrack_free(conntrack);
711                 DEBUGP("init conntrack: can't track with proto module\n");
712                 return NULL;
713         }
714
715         write_lock_bh(&nf_conntrack_lock);
716         exp = find_expectation(tuple);
717
718         if (exp) {
719                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
720                         conntrack, exp);
721                 /* Welcome, Mr. Bond.  We've been expecting you... */
722                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
723                 conntrack->master = exp->master;
724                 if (exp->helper)
725                         nfct_help(conntrack)->helper = exp->helper;
726 #ifdef CONFIG_NF_CONNTRACK_MARK
727                 conntrack->mark = exp->master->mark;
728 #endif
729 #ifdef CONFIG_NF_CONNTRACK_SECMARK
730                 conntrack->secmark = exp->master->secmark;
731 #endif
732                 nf_conntrack_get(&conntrack->master->ct_general);
733                 NF_CT_STAT_INC(expect_new);
734         } else {
735                 struct nf_conn_help *help = nfct_help(conntrack);
736
737                 if (help)
738                         help->helper = __nf_ct_helper_find(&repl_tuple);
739                 NF_CT_STAT_INC(new);
740         }
741
742         /* Overload tuple linked list to put us in unconfirmed list. */
743         list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
744
745         write_unlock_bh(&nf_conntrack_lock);
746
747         if (exp) {
748                 if (exp->expectfn)
749                         exp->expectfn(conntrack, exp);
750                 nf_conntrack_expect_put(exp);
751         }
752
753         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
754 }
755
756 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
757 static inline struct nf_conn *
758 resolve_normal_ct(struct sk_buff *skb,
759                   unsigned int dataoff,
760                   u_int16_t l3num,
761                   u_int8_t protonum,
762                   struct nf_conntrack_l3proto *l3proto,
763                   struct nf_conntrack_l4proto *l4proto,
764                   int *set_reply,
765                   enum ip_conntrack_info *ctinfo)
766 {
767         struct nf_conntrack_tuple tuple;
768         struct nf_conntrack_tuple_hash *h;
769         struct nf_conn *ct;
770
771         if (!nf_ct_get_tuple(skb, (unsigned int)(skb->nh.raw - skb->data),
772                              dataoff, l3num, protonum, &tuple, l3proto,
773                              l4proto)) {
774                 DEBUGP("resolve_normal_ct: Can't get tuple\n");
775                 return NULL;
776         }
777
778         /* look for tuple match */
779         h = nf_conntrack_find_get(&tuple, NULL);
780         if (!h) {
781                 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
782                 if (!h)
783                         return NULL;
784                 if (IS_ERR(h))
785                         return (void *)h;
786         }
787         ct = nf_ct_tuplehash_to_ctrack(h);
788
789         /* It exists; we have (non-exclusive) reference. */
790         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
791                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
792                 /* Please set reply bit if this packet OK */
793                 *set_reply = 1;
794         } else {
795                 /* Once we've had two way comms, always ESTABLISHED. */
796                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
797                         DEBUGP("nf_conntrack_in: normal packet for %p\n", ct);
798                         *ctinfo = IP_CT_ESTABLISHED;
799                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
800                         DEBUGP("nf_conntrack_in: related packet for %p\n", ct);
801                         *ctinfo = IP_CT_RELATED;
802                 } else {
803                         DEBUGP("nf_conntrack_in: new packet for %p\n", ct);
804                         *ctinfo = IP_CT_NEW;
805                 }
806                 *set_reply = 0;
807         }
808         skb->nfct = &ct->ct_general;
809         skb->nfctinfo = *ctinfo;
810         return ct;
811 }
812
813 unsigned int
814 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
815 {
816         struct nf_conn *ct;
817         enum ip_conntrack_info ctinfo;
818         struct nf_conntrack_l3proto *l3proto;
819         struct nf_conntrack_l4proto *l4proto;
820         unsigned int dataoff;
821         u_int8_t protonum;
822         int set_reply = 0;
823         int ret;
824
825         /* Previously seen (loopback or untracked)?  Ignore. */
826         if ((*pskb)->nfct) {
827                 NF_CT_STAT_INC_ATOMIC(ignore);
828                 return NF_ACCEPT;
829         }
830
831         /* rcu_read_lock()ed by nf_hook_slow */
832         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
833
834         if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) {
835                 DEBUGP("not prepared to track yet or error occured\n");
836                 return -ret;
837         }
838
839         l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
840
841         /* It may be an special packet, error, unclean...
842          * inverse of the return code tells to the netfilter
843          * core what to do with the packet. */
844         if (l4proto->error != NULL &&
845             (ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
846                 NF_CT_STAT_INC_ATOMIC(error);
847                 NF_CT_STAT_INC_ATOMIC(invalid);
848                 return -ret;
849         }
850
851         ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, l4proto,
852                                &set_reply, &ctinfo);
853         if (!ct) {
854                 /* Not valid part of a connection */
855                 NF_CT_STAT_INC_ATOMIC(invalid);
856                 return NF_ACCEPT;
857         }
858
859         if (IS_ERR(ct)) {
860                 /* Too stressed to deal. */
861                 NF_CT_STAT_INC_ATOMIC(drop);
862                 return NF_DROP;
863         }
864
865         NF_CT_ASSERT((*pskb)->nfct);
866
867         ret = l4proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
868         if (ret < 0) {
869                 /* Invalid: inverse of the return code tells
870                  * the netfilter core what to do */
871                 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
872                 nf_conntrack_put((*pskb)->nfct);
873                 (*pskb)->nfct = NULL;
874                 NF_CT_STAT_INC_ATOMIC(invalid);
875                 return -ret;
876         }
877
878         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
879                 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
880
881         return ret;
882 }
883 EXPORT_SYMBOL_GPL(nf_conntrack_in);
884
885 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
886                          const struct nf_conntrack_tuple *orig)
887 {
888         int ret;
889
890         rcu_read_lock();
891         ret = nf_ct_invert_tuple(inverse, orig,
892                                  __nf_ct_l3proto_find(orig->src.l3num),
893                                  __nf_ct_l4proto_find(orig->src.l3num,
894                                                       orig->dst.protonum));
895         rcu_read_unlock();
896         return ret;
897 }
898 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
899
900 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
901    implicitly racy: see __nf_conntrack_confirm */
902 void nf_conntrack_alter_reply(struct nf_conn *ct,
903                               const struct nf_conntrack_tuple *newreply)
904 {
905         struct nf_conn_help *help = nfct_help(ct);
906
907         write_lock_bh(&nf_conntrack_lock);
908         /* Should be unconfirmed, so not in hash table yet */
909         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
910
911         DEBUGP("Altering reply tuple of %p to ", ct);
912         NF_CT_DUMP_TUPLE(newreply);
913
914         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
915         if (!ct->master && help && help->expecting == 0)
916                 help->helper = __nf_ct_helper_find(newreply);
917         write_unlock_bh(&nf_conntrack_lock);
918 }
919 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
920
921 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
922 void __nf_ct_refresh_acct(struct nf_conn *ct,
923                           enum ip_conntrack_info ctinfo,
924                           const struct sk_buff *skb,
925                           unsigned long extra_jiffies,
926                           int do_acct)
927 {
928         int event = 0;
929
930         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
931         NF_CT_ASSERT(skb);
932
933         write_lock_bh(&nf_conntrack_lock);
934
935         /* Only update if this is not a fixed timeout */
936         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
937                 write_unlock_bh(&nf_conntrack_lock);
938                 return;
939         }
940
941         /* If not in hash table, timer will not be active yet */
942         if (!nf_ct_is_confirmed(ct)) {
943                 ct->timeout.expires = extra_jiffies;
944                 event = IPCT_REFRESH;
945         } else {
946                 unsigned long newtime = jiffies + extra_jiffies;
947
948                 /* Only update the timeout if the new timeout is at least
949                    HZ jiffies from the old timeout. Need del_timer for race
950                    avoidance (may already be dying). */
951                 if (newtime - ct->timeout.expires >= HZ
952                     && del_timer(&ct->timeout)) {
953                         ct->timeout.expires = newtime;
954                         add_timer(&ct->timeout);
955                         event = IPCT_REFRESH;
956                 }
957         }
958
959 #ifdef CONFIG_NF_CT_ACCT
960         if (do_acct) {
961                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
962                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
963                         skb->len - (unsigned int)(skb->nh.raw - skb->data);
964
965                 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
966                     || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
967                         event |= IPCT_COUNTER_FILLING;
968         }
969 #endif
970
971         write_unlock_bh(&nf_conntrack_lock);
972
973         /* must be unlocked when calling event cache */
974         if (event)
975                 nf_conntrack_event_cache(event, skb);
976 }
977 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
978
979 #if defined(CONFIG_NF_CT_NETLINK) || \
980     defined(CONFIG_NF_CT_NETLINK_MODULE)
981
982 #include <linux/netfilter/nfnetlink.h>
983 #include <linux/netfilter/nfnetlink_conntrack.h>
984 #include <linux/mutex.h>
985
986
987 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
988  * in ip_conntrack_core, since we don't want the protocols to autoload
989  * or depend on ctnetlink */
990 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
991                                const struct nf_conntrack_tuple *tuple)
992 {
993         NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
994                 &tuple->src.u.tcp.port);
995         NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
996                 &tuple->dst.u.tcp.port);
997         return 0;
998
999 nfattr_failure:
1000         return -1;
1001 }
1002 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr);
1003
1004 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
1005         [CTA_PROTO_SRC_PORT-1]  = sizeof(u_int16_t),
1006         [CTA_PROTO_DST_PORT-1]  = sizeof(u_int16_t)
1007 };
1008
1009 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
1010                                struct nf_conntrack_tuple *t)
1011 {
1012         if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
1013                 return -EINVAL;
1014
1015         if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
1016                 return -EINVAL;
1017
1018         t->src.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
1019         t->dst.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
1020
1021         return 0;
1022 }
1023 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple);
1024 #endif
1025
1026 /* Used by ipt_REJECT and ip6t_REJECT. */
1027 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1028 {
1029         struct nf_conn *ct;
1030         enum ip_conntrack_info ctinfo;
1031
1032         /* This ICMP is in reverse direction to the packet which caused it */
1033         ct = nf_ct_get(skb, &ctinfo);
1034         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1035                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
1036         else
1037                 ctinfo = IP_CT_RELATED;
1038
1039         /* Attach to new skbuff, and increment count */
1040         nskb->nfct = &ct->ct_general;
1041         nskb->nfctinfo = ctinfo;
1042         nf_conntrack_get(nskb->nfct);
1043 }
1044 EXPORT_SYMBOL_GPL(__nf_conntrack_attach);
1045
1046 static inline int
1047 do_iter(const struct nf_conntrack_tuple_hash *i,
1048         int (*iter)(struct nf_conn *i, void *data),
1049         void *data)
1050 {
1051         return iter(nf_ct_tuplehash_to_ctrack(i), data);
1052 }
1053
1054 /* Bring out ya dead! */
1055 static struct nf_conn *
1056 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
1057                 void *data, unsigned int *bucket)
1058 {
1059         struct nf_conntrack_tuple_hash *h;
1060         struct nf_conn *ct;
1061
1062         write_lock_bh(&nf_conntrack_lock);
1063         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1064                 list_for_each_entry(h, &nf_conntrack_hash[*bucket], list) {
1065                         ct = nf_ct_tuplehash_to_ctrack(h);
1066                         if (iter(ct, data))
1067                                 goto found;
1068                 }
1069         }
1070         list_for_each_entry(h, &unconfirmed, list) {
1071                 ct = nf_ct_tuplehash_to_ctrack(h);
1072                 if (iter(ct, data))
1073                         set_bit(IPS_DYING_BIT, &ct->status);
1074         }
1075         write_unlock_bh(&nf_conntrack_lock);
1076         return NULL;
1077 found:
1078         atomic_inc(&ct->ct_general.use);
1079         write_unlock_bh(&nf_conntrack_lock);
1080         return ct;
1081 }
1082
1083 void
1084 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
1085 {
1086         struct nf_conn *ct;
1087         unsigned int bucket = 0;
1088
1089         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1090                 /* Time to push up daises... */
1091                 if (del_timer(&ct->timeout))
1092                         death_by_timeout((unsigned long)ct);
1093                 /* ... else the timer will get him soon. */
1094
1095                 nf_ct_put(ct);
1096         }
1097 }
1098 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1099
1100 static int kill_all(struct nf_conn *i, void *data)
1101 {
1102         return 1;
1103 }
1104
1105 static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
1106 {
1107         if (vmalloced)
1108                 vfree(hash);
1109         else
1110                 free_pages((unsigned long)hash,
1111                            get_order(sizeof(struct list_head) * size));
1112 }
1113
1114 void nf_conntrack_flush(void)
1115 {
1116         nf_ct_iterate_cleanup(kill_all, NULL);
1117 }
1118 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1119
1120 /* Mishearing the voices in his head, our hero wonders how he's
1121    supposed to kill the mall. */
1122 void nf_conntrack_cleanup(void)
1123 {
1124         int i;
1125
1126         rcu_assign_pointer(ip_ct_attach, NULL);
1127
1128         /* This makes sure all current packets have passed through
1129            netfilter framework.  Roll on, two-stage module
1130            delete... */
1131         synchronize_net();
1132
1133         nf_ct_event_cache_flush();
1134  i_see_dead_people:
1135         nf_conntrack_flush();
1136         if (atomic_read(&nf_conntrack_count) != 0) {
1137                 schedule();
1138                 goto i_see_dead_people;
1139         }
1140         /* wait until all references to nf_conntrack_untracked are dropped */
1141         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1142                 schedule();
1143
1144         for (i = 0; i < NF_CT_F_NUM; i++) {
1145                 if (nf_ct_cache[i].use == 0)
1146                         continue;
1147
1148                 NF_CT_ASSERT(nf_ct_cache[i].use == 1);
1149                 nf_ct_cache[i].use = 1;
1150                 nf_conntrack_unregister_cache(i);
1151         }
1152         kmem_cache_destroy(nf_conntrack_expect_cachep);
1153         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1154                             nf_conntrack_htable_size);
1155
1156         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_generic);
1157
1158         /* free l3proto protocol tables */
1159         for (i = 0; i < PF_MAX; i++)
1160                 if (nf_ct_protos[i]) {
1161                         kfree(nf_ct_protos[i]);
1162                         nf_ct_protos[i] = NULL;
1163                 }
1164 }
1165
1166 static struct list_head *alloc_hashtable(int size, int *vmalloced)
1167 {
1168         struct list_head *hash;
1169         unsigned int i;
1170
1171         *vmalloced = 0;
1172         hash = (void*)__get_free_pages(GFP_KERNEL,
1173                                        get_order(sizeof(struct list_head)
1174                                                  * size));
1175         if (!hash) {
1176                 *vmalloced = 1;
1177                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1178                 hash = vmalloc(sizeof(struct list_head) * size);
1179         }
1180
1181         if (hash)
1182                 for (i = 0; i < size; i++)
1183                         INIT_LIST_HEAD(&hash[i]);
1184
1185         return hash;
1186 }
1187
1188 int set_hashsize(const char *val, struct kernel_param *kp)
1189 {
1190         int i, bucket, hashsize, vmalloced;
1191         int old_vmalloced, old_size;
1192         int rnd;
1193         struct list_head *hash, *old_hash;
1194         struct nf_conntrack_tuple_hash *h;
1195
1196         /* On boot, we can set this without any fancy locking. */
1197         if (!nf_conntrack_htable_size)
1198                 return param_set_uint(val, kp);
1199
1200         hashsize = simple_strtol(val, NULL, 0);
1201         if (!hashsize)
1202                 return -EINVAL;
1203
1204         hash = alloc_hashtable(hashsize, &vmalloced);
1205         if (!hash)
1206                 return -ENOMEM;
1207
1208         /* We have to rehahs for the new table anyway, so we also can
1209          * use a newrandom seed */
1210         get_random_bytes(&rnd, 4);
1211
1212         write_lock_bh(&nf_conntrack_lock);
1213         for (i = 0; i < nf_conntrack_htable_size; i++) {
1214                 while (!list_empty(&nf_conntrack_hash[i])) {
1215                         h = list_entry(nf_conntrack_hash[i].next,
1216                                        struct nf_conntrack_tuple_hash, list);
1217                         list_del(&h->list);
1218                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1219                         list_add_tail(&h->list, &hash[bucket]);
1220                 }
1221         }
1222         old_size = nf_conntrack_htable_size;
1223         old_vmalloced = nf_conntrack_vmalloc;
1224         old_hash = nf_conntrack_hash;
1225
1226         nf_conntrack_htable_size = hashsize;
1227         nf_conntrack_vmalloc = vmalloced;
1228         nf_conntrack_hash = hash;
1229         nf_conntrack_hash_rnd = rnd;
1230         write_unlock_bh(&nf_conntrack_lock);
1231
1232         free_conntrack_hash(old_hash, old_vmalloced, old_size);
1233         return 0;
1234 }
1235
1236 module_param_call(hashsize, set_hashsize, param_get_uint,
1237                   &nf_conntrack_htable_size, 0600);
1238
1239 int __init nf_conntrack_init(void)
1240 {
1241         unsigned int i;
1242         int ret;
1243
1244         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1245          * machine has 256 buckets.  >= 1GB machines have 8192 buckets. */
1246         if (!nf_conntrack_htable_size) {
1247                 nf_conntrack_htable_size
1248                         = (((num_physpages << PAGE_SHIFT) / 16384)
1249                            / sizeof(struct list_head));
1250                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1251                         nf_conntrack_htable_size = 8192;
1252                 if (nf_conntrack_htable_size < 16)
1253                         nf_conntrack_htable_size = 16;
1254         }
1255         nf_conntrack_max = 8 * nf_conntrack_htable_size;
1256
1257         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1258                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1259                nf_conntrack_max);
1260
1261         nf_conntrack_hash = alloc_hashtable(nf_conntrack_htable_size,
1262                                             &nf_conntrack_vmalloc);
1263         if (!nf_conntrack_hash) {
1264                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1265                 goto err_out;
1266         }
1267
1268         ret = nf_conntrack_register_cache(NF_CT_F_BASIC, "nf_conntrack:basic",
1269                                           sizeof(struct nf_conn));
1270         if (ret < 0) {
1271                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1272                 goto err_free_hash;
1273         }
1274
1275         nf_conntrack_expect_cachep = kmem_cache_create("nf_conntrack_expect",
1276                                         sizeof(struct nf_conntrack_expect),
1277                                         0, 0, NULL, NULL);
1278         if (!nf_conntrack_expect_cachep) {
1279                 printk(KERN_ERR "Unable to create nf_expect slab cache\n");
1280                 goto err_free_conntrack_slab;
1281         }
1282
1283         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_generic);
1284         if (ret < 0)
1285                 goto out_free_expect_slab;
1286
1287         /* Don't NEED lock here, but good form anyway. */
1288         write_lock_bh(&nf_conntrack_lock);
1289         for (i = 0; i < AF_MAX; i++)
1290                 nf_ct_l3protos[i] = &nf_conntrack_l3proto_generic;
1291         write_unlock_bh(&nf_conntrack_lock);
1292
1293         /* For use by REJECT target */
1294         rcu_assign_pointer(ip_ct_attach, __nf_conntrack_attach);
1295
1296         /* Set up fake conntrack:
1297             - to never be deleted, not in any hashes */
1298         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1299         /*  - and look it like as a confirmed connection */
1300         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1301
1302         return ret;
1303
1304 out_free_expect_slab:
1305         kmem_cache_destroy(nf_conntrack_expect_cachep);
1306 err_free_conntrack_slab:
1307         nf_conntrack_unregister_cache(NF_CT_F_BASIC);
1308 err_free_hash:
1309         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1310                             nf_conntrack_htable_size);
1311 err_out:
1312         return -ENOMEM;
1313 }