netfilter: don't use INIT_RCU_HEAD()
[linux-2.6.git] / net / netfilter / nf_conntrack_core.c
1 /* Connection state tracking for netfilter.  This is separated from,
2    but required by, the NAT layer; it can also be used by an iptables
3    extension. */
4
5 /* (C) 1999-2001 Paul `Rusty' Russell
6  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
7  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13
14 #include <linux/types.h>
15 #include <linux/netfilter.h>
16 #include <linux/module.h>
17 #include <linux/sched.h>
18 #include <linux/skbuff.h>
19 #include <linux/proc_fs.h>
20 #include <linux/vmalloc.h>
21 #include <linux/stddef.h>
22 #include <linux/slab.h>
23 #include <linux/random.h>
24 #include <linux/jhash.h>
25 #include <linux/err.h>
26 #include <linux/percpu.h>
27 #include <linux/moduleparam.h>
28 #include <linux/notifier.h>
29 #include <linux/kernel.h>
30 #include <linux/netdevice.h>
31 #include <linux/socket.h>
32 #include <linux/mm.h>
33 #include <linux/nsproxy.h>
34 #include <linux/rculist_nulls.h>
35
36 #include <net/netfilter/nf_conntrack.h>
37 #include <net/netfilter/nf_conntrack_l3proto.h>
38 #include <net/netfilter/nf_conntrack_l4proto.h>
39 #include <net/netfilter/nf_conntrack_expect.h>
40 #include <net/netfilter/nf_conntrack_helper.h>
41 #include <net/netfilter/nf_conntrack_core.h>
42 #include <net/netfilter/nf_conntrack_extend.h>
43 #include <net/netfilter/nf_conntrack_acct.h>
44 #include <net/netfilter/nf_conntrack_ecache.h>
45 #include <net/netfilter/nf_nat.h>
46 #include <net/netfilter/nf_nat_core.h>
47
48 #define NF_CONNTRACK_VERSION    "0.5.0"
49
50 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
51                                       enum nf_nat_manip_type manip,
52                                       const struct nlattr *attr) __read_mostly;
53 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
54
55 DEFINE_SPINLOCK(nf_conntrack_lock);
56 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
57
58 unsigned int nf_conntrack_htable_size __read_mostly;
59 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
60
61 unsigned int nf_conntrack_max __read_mostly;
62 EXPORT_SYMBOL_GPL(nf_conntrack_max);
63
64 struct nf_conn nf_conntrack_untracked __read_mostly;
65 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
66
67 static int nf_conntrack_hash_rnd_initted;
68 static unsigned int nf_conntrack_hash_rnd;
69
70 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
71                                   unsigned int size, unsigned int rnd)
72 {
73         unsigned int n;
74         u_int32_t h;
75
76         /* The direction must be ignored, so we hash everything up to the
77          * destination ports (which is a multiple of 4) and treat the last
78          * three bytes manually.
79          */
80         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
81         h = jhash2((u32 *)tuple, n,
82                    rnd ^ (((__force __u16)tuple->dst.u.all << 16) |
83                           tuple->dst.protonum));
84
85         return ((u64)h * size) >> 32;
86 }
87
88 static inline u_int32_t hash_conntrack(const struct net *net,
89                                        const struct nf_conntrack_tuple *tuple)
90 {
91         return __hash_conntrack(tuple, net->ct.htable_size,
92                                 nf_conntrack_hash_rnd);
93 }
94
95 bool
96 nf_ct_get_tuple(const struct sk_buff *skb,
97                 unsigned int nhoff,
98                 unsigned int dataoff,
99                 u_int16_t l3num,
100                 u_int8_t protonum,
101                 struct nf_conntrack_tuple *tuple,
102                 const struct nf_conntrack_l3proto *l3proto,
103                 const struct nf_conntrack_l4proto *l4proto)
104 {
105         memset(tuple, 0, sizeof(*tuple));
106
107         tuple->src.l3num = l3num;
108         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
109                 return false;
110
111         tuple->dst.protonum = protonum;
112         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
113
114         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
115 }
116 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
117
118 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
119                        u_int16_t l3num, struct nf_conntrack_tuple *tuple)
120 {
121         struct nf_conntrack_l3proto *l3proto;
122         struct nf_conntrack_l4proto *l4proto;
123         unsigned int protoff;
124         u_int8_t protonum;
125         int ret;
126
127         rcu_read_lock();
128
129         l3proto = __nf_ct_l3proto_find(l3num);
130         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
131         if (ret != NF_ACCEPT) {
132                 rcu_read_unlock();
133                 return false;
134         }
135
136         l4proto = __nf_ct_l4proto_find(l3num, protonum);
137
138         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
139                               l3proto, l4proto);
140
141         rcu_read_unlock();
142         return ret;
143 }
144 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
145
146 bool
147 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
148                    const struct nf_conntrack_tuple *orig,
149                    const struct nf_conntrack_l3proto *l3proto,
150                    const struct nf_conntrack_l4proto *l4proto)
151 {
152         memset(inverse, 0, sizeof(*inverse));
153
154         inverse->src.l3num = orig->src.l3num;
155         if (l3proto->invert_tuple(inverse, orig) == 0)
156                 return false;
157
158         inverse->dst.dir = !orig->dst.dir;
159
160         inverse->dst.protonum = orig->dst.protonum;
161         return l4proto->invert_tuple(inverse, orig);
162 }
163 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
164
165 static void
166 clean_from_lists(struct nf_conn *ct)
167 {
168         pr_debug("clean_from_lists(%p)\n", ct);
169         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
170         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
171
172         /* Destroy all pending expectations */
173         nf_ct_remove_expectations(ct);
174 }
175
176 static void
177 destroy_conntrack(struct nf_conntrack *nfct)
178 {
179         struct nf_conn *ct = (struct nf_conn *)nfct;
180         struct net *net = nf_ct_net(ct);
181         struct nf_conntrack_l4proto *l4proto;
182
183         pr_debug("destroy_conntrack(%p)\n", ct);
184         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
185         NF_CT_ASSERT(!timer_pending(&ct->timeout));
186
187         /* To make sure we don't get any weird locking issues here:
188          * destroy_conntrack() MUST NOT be called with a write lock
189          * to nf_conntrack_lock!!! -HW */
190         rcu_read_lock();
191         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
192         if (l4proto && l4proto->destroy)
193                 l4proto->destroy(ct);
194
195         rcu_read_unlock();
196
197         spin_lock_bh(&nf_conntrack_lock);
198         /* Expectations will have been removed in clean_from_lists,
199          * except TFTP can create an expectation on the first packet,
200          * before connection is in the list, so we need to clean here,
201          * too. */
202         nf_ct_remove_expectations(ct);
203
204         /* We overload first tuple to link into unconfirmed list. */
205         if (!nf_ct_is_confirmed(ct)) {
206                 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
207                 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
208         }
209
210         NF_CT_STAT_INC(net, delete);
211         spin_unlock_bh(&nf_conntrack_lock);
212
213         if (ct->master)
214                 nf_ct_put(ct->master);
215
216         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
217         nf_conntrack_free(ct);
218 }
219
220 void nf_ct_delete_from_lists(struct nf_conn *ct)
221 {
222         struct net *net = nf_ct_net(ct);
223
224         nf_ct_helper_destroy(ct);
225         spin_lock_bh(&nf_conntrack_lock);
226         /* Inside lock so preempt is disabled on module removal path.
227          * Otherwise we can get spurious warnings. */
228         NF_CT_STAT_INC(net, delete_list);
229         clean_from_lists(ct);
230         spin_unlock_bh(&nf_conntrack_lock);
231 }
232 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
233
234 static void death_by_event(unsigned long ul_conntrack)
235 {
236         struct nf_conn *ct = (void *)ul_conntrack;
237         struct net *net = nf_ct_net(ct);
238
239         if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
240                 /* bad luck, let's retry again */
241                 ct->timeout.expires = jiffies +
242                         (random32() % net->ct.sysctl_events_retry_timeout);
243                 add_timer(&ct->timeout);
244                 return;
245         }
246         /* we've got the event delivered, now it's dying */
247         set_bit(IPS_DYING_BIT, &ct->status);
248         spin_lock(&nf_conntrack_lock);
249         hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
250         spin_unlock(&nf_conntrack_lock);
251         nf_ct_put(ct);
252 }
253
254 void nf_ct_insert_dying_list(struct nf_conn *ct)
255 {
256         struct net *net = nf_ct_net(ct);
257
258         /* add this conntrack to the dying list */
259         spin_lock_bh(&nf_conntrack_lock);
260         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
261                              &net->ct.dying);
262         spin_unlock_bh(&nf_conntrack_lock);
263         /* set a new timer to retry event delivery */
264         setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
265         ct->timeout.expires = jiffies +
266                 (random32() % net->ct.sysctl_events_retry_timeout);
267         add_timer(&ct->timeout);
268 }
269 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
270
271 static void death_by_timeout(unsigned long ul_conntrack)
272 {
273         struct nf_conn *ct = (void *)ul_conntrack;
274
275         if (!test_bit(IPS_DYING_BIT, &ct->status) &&
276             unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
277                 /* destroy event was not delivered */
278                 nf_ct_delete_from_lists(ct);
279                 nf_ct_insert_dying_list(ct);
280                 return;
281         }
282         set_bit(IPS_DYING_BIT, &ct->status);
283         nf_ct_delete_from_lists(ct);
284         nf_ct_put(ct);
285 }
286
287 /*
288  * Warning :
289  * - Caller must take a reference on returned object
290  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
291  * OR
292  * - Caller must lock nf_conntrack_lock before calling this function
293  */
294 struct nf_conntrack_tuple_hash *
295 __nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple)
296 {
297         struct nf_conntrack_tuple_hash *h;
298         struct hlist_nulls_node *n;
299         unsigned int hash = hash_conntrack(net, tuple);
300
301         /* Disable BHs the entire time since we normally need to disable them
302          * at least once for the stats anyway.
303          */
304         local_bh_disable();
305 begin:
306         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
307                 if (nf_ct_tuple_equal(tuple, &h->tuple)) {
308                         NF_CT_STAT_INC(net, found);
309                         local_bh_enable();
310                         return h;
311                 }
312                 NF_CT_STAT_INC(net, searched);
313         }
314         /*
315          * if the nulls value we got at the end of this lookup is
316          * not the expected one, we must restart lookup.
317          * We probably met an item that was moved to another chain.
318          */
319         if (get_nulls_value(n) != hash)
320                 goto begin;
321         local_bh_enable();
322
323         return NULL;
324 }
325 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
326
327 /* Find a connection corresponding to a tuple. */
328 struct nf_conntrack_tuple_hash *
329 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple)
330 {
331         struct nf_conntrack_tuple_hash *h;
332         struct nf_conn *ct;
333
334         rcu_read_lock();
335 begin:
336         h = __nf_conntrack_find(net, tuple);
337         if (h) {
338                 ct = nf_ct_tuplehash_to_ctrack(h);
339                 if (unlikely(nf_ct_is_dying(ct) ||
340                              !atomic_inc_not_zero(&ct->ct_general.use)))
341                         h = NULL;
342                 else {
343                         if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) {
344                                 nf_ct_put(ct);
345                                 goto begin;
346                         }
347                 }
348         }
349         rcu_read_unlock();
350
351         return h;
352 }
353 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
354
355 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
356                                        unsigned int hash,
357                                        unsigned int repl_hash)
358 {
359         struct net *net = nf_ct_net(ct);
360
361         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
362                            &net->ct.hash[hash]);
363         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
364                            &net->ct.hash[repl_hash]);
365 }
366
367 void nf_conntrack_hash_insert(struct nf_conn *ct)
368 {
369         struct net *net = nf_ct_net(ct);
370         unsigned int hash, repl_hash;
371
372         hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
373         repl_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
374
375         __nf_conntrack_hash_insert(ct, hash, repl_hash);
376 }
377 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
378
379 /* Confirm a connection given skb; places it in hash table */
380 int
381 __nf_conntrack_confirm(struct sk_buff *skb)
382 {
383         unsigned int hash, repl_hash;
384         struct nf_conntrack_tuple_hash *h;
385         struct nf_conn *ct;
386         struct nf_conn_help *help;
387         struct hlist_nulls_node *n;
388         enum ip_conntrack_info ctinfo;
389         struct net *net;
390
391         ct = nf_ct_get(skb, &ctinfo);
392         net = nf_ct_net(ct);
393
394         /* ipt_REJECT uses nf_conntrack_attach to attach related
395            ICMP/TCP RST packets in other direction.  Actual packet
396            which created connection will be IP_CT_NEW or for an
397            expected connection, IP_CT_RELATED. */
398         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
399                 return NF_ACCEPT;
400
401         hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
402         repl_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
403
404         /* We're not in hash table, and we refuse to set up related
405            connections for unconfirmed conns.  But packet copies and
406            REJECT will give spurious warnings here. */
407         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
408
409         /* No external references means noone else could have
410            confirmed us. */
411         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
412         pr_debug("Confirming conntrack %p\n", ct);
413
414         spin_lock_bh(&nf_conntrack_lock);
415
416         /* See if there's one in the list already, including reverse:
417            NAT could have grabbed it without realizing, since we're
418            not in the hash.  If there is, we lost race. */
419         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
420                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
421                                       &h->tuple))
422                         goto out;
423         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
424                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
425                                       &h->tuple))
426                         goto out;
427
428         /* Remove from unconfirmed list */
429         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
430
431         /* Timer relative to confirmation time, not original
432            setting time, otherwise we'd get timer wrap in
433            weird delay cases. */
434         ct->timeout.expires += jiffies;
435         add_timer(&ct->timeout);
436         atomic_inc(&ct->ct_general.use);
437         set_bit(IPS_CONFIRMED_BIT, &ct->status);
438
439         /* Since the lookup is lockless, hash insertion must be done after
440          * starting the timer and setting the CONFIRMED bit. The RCU barriers
441          * guarantee that no other CPU can find the conntrack before the above
442          * stores are visible.
443          */
444         __nf_conntrack_hash_insert(ct, hash, repl_hash);
445         NF_CT_STAT_INC(net, insert);
446         spin_unlock_bh(&nf_conntrack_lock);
447
448         help = nfct_help(ct);
449         if (help && help->helper)
450                 nf_conntrack_event_cache(IPCT_HELPER, ct);
451
452         nf_conntrack_event_cache(master_ct(ct) ?
453                                  IPCT_RELATED : IPCT_NEW, ct);
454         return NF_ACCEPT;
455
456 out:
457         NF_CT_STAT_INC(net, insert_failed);
458         spin_unlock_bh(&nf_conntrack_lock);
459         return NF_DROP;
460 }
461 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
462
463 /* Returns true if a connection correspondings to the tuple (required
464    for NAT). */
465 int
466 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
467                          const struct nf_conn *ignored_conntrack)
468 {
469         struct net *net = nf_ct_net(ignored_conntrack);
470         struct nf_conntrack_tuple_hash *h;
471         struct hlist_nulls_node *n;
472         unsigned int hash = hash_conntrack(net, tuple);
473
474         /* Disable BHs the entire time since we need to disable them at
475          * least once for the stats anyway.
476          */
477         rcu_read_lock_bh();
478         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
479                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
480                     nf_ct_tuple_equal(tuple, &h->tuple)) {
481                         NF_CT_STAT_INC(net, found);
482                         rcu_read_unlock_bh();
483                         return 1;
484                 }
485                 NF_CT_STAT_INC(net, searched);
486         }
487         rcu_read_unlock_bh();
488
489         return 0;
490 }
491 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
492
493 #define NF_CT_EVICTION_RANGE    8
494
495 /* There's a small race here where we may free a just-assured
496    connection.  Too bad: we're in trouble anyway. */
497 static noinline int early_drop(struct net *net, unsigned int hash)
498 {
499         /* Use oldest entry, which is roughly LRU */
500         struct nf_conntrack_tuple_hash *h;
501         struct nf_conn *ct = NULL, *tmp;
502         struct hlist_nulls_node *n;
503         unsigned int i, cnt = 0;
504         int dropped = 0;
505
506         rcu_read_lock();
507         for (i = 0; i < net->ct.htable_size; i++) {
508                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
509                                          hnnode) {
510                         tmp = nf_ct_tuplehash_to_ctrack(h);
511                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
512                                 ct = tmp;
513                         cnt++;
514                 }
515
516                 if (ct != NULL) {
517                         if (likely(!nf_ct_is_dying(ct) &&
518                                    atomic_inc_not_zero(&ct->ct_general.use)))
519                                 break;
520                         else
521                                 ct = NULL;
522                 }
523
524                 if (cnt >= NF_CT_EVICTION_RANGE)
525                         break;
526
527                 hash = (hash + 1) % net->ct.htable_size;
528         }
529         rcu_read_unlock();
530
531         if (!ct)
532                 return dropped;
533
534         if (del_timer(&ct->timeout)) {
535                 death_by_timeout((unsigned long)ct);
536                 dropped = 1;
537                 NF_CT_STAT_INC_ATOMIC(net, early_drop);
538         }
539         nf_ct_put(ct);
540         return dropped;
541 }
542
543 struct nf_conn *nf_conntrack_alloc(struct net *net,
544                                    const struct nf_conntrack_tuple *orig,
545                                    const struct nf_conntrack_tuple *repl,
546                                    gfp_t gfp)
547 {
548         struct nf_conn *ct;
549
550         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
551                 get_random_bytes(&nf_conntrack_hash_rnd,
552                                 sizeof(nf_conntrack_hash_rnd));
553                 nf_conntrack_hash_rnd_initted = 1;
554         }
555
556         /* We don't want any race condition at early drop stage */
557         atomic_inc(&net->ct.count);
558
559         if (nf_conntrack_max &&
560             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
561                 unsigned int hash = hash_conntrack(net, orig);
562                 if (!early_drop(net, hash)) {
563                         atomic_dec(&net->ct.count);
564                         if (net_ratelimit())
565                                 printk(KERN_WARNING
566                                        "nf_conntrack: table full, dropping"
567                                        " packet.\n");
568                         return ERR_PTR(-ENOMEM);
569                 }
570         }
571
572         /*
573          * Do not use kmem_cache_zalloc(), as this cache uses
574          * SLAB_DESTROY_BY_RCU.
575          */
576         ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
577         if (ct == NULL) {
578                 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
579                 atomic_dec(&net->ct.count);
580                 return ERR_PTR(-ENOMEM);
581         }
582         /*
583          * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
584          * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
585          */
586         memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
587                sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
588         spin_lock_init(&ct->lock);
589         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
590         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
591         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
592         ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev = NULL;
593         /* Don't set timer yet: wait for confirmation */
594         setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
595 #ifdef CONFIG_NET_NS
596         ct->ct_net = net;
597 #endif
598
599         /*
600          * changes to lookup keys must be done before setting refcnt to 1
601          */
602         smp_wmb();
603         atomic_set(&ct->ct_general.use, 1);
604         return ct;
605 }
606 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
607
608 void nf_conntrack_free(struct nf_conn *ct)
609 {
610         struct net *net = nf_ct_net(ct);
611
612         nf_ct_ext_destroy(ct);
613         atomic_dec(&net->ct.count);
614         nf_ct_ext_free(ct);
615         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
616 }
617 EXPORT_SYMBOL_GPL(nf_conntrack_free);
618
619 /* Allocate a new conntrack: we return -ENOMEM if classification
620    failed due to stress.  Otherwise it really is unclassifiable. */
621 static struct nf_conntrack_tuple_hash *
622 init_conntrack(struct net *net, struct nf_conn *tmpl,
623                const struct nf_conntrack_tuple *tuple,
624                struct nf_conntrack_l3proto *l3proto,
625                struct nf_conntrack_l4proto *l4proto,
626                struct sk_buff *skb,
627                unsigned int dataoff)
628 {
629         struct nf_conn *ct;
630         struct nf_conn_help *help;
631         struct nf_conntrack_tuple repl_tuple;
632         struct nf_conntrack_ecache *ecache;
633         struct nf_conntrack_expect *exp;
634
635         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
636                 pr_debug("Can't invert tuple.\n");
637                 return NULL;
638         }
639
640         ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC);
641         if (IS_ERR(ct)) {
642                 pr_debug("Can't allocate conntrack.\n");
643                 return (struct nf_conntrack_tuple_hash *)ct;
644         }
645
646         if (!l4proto->new(ct, skb, dataoff)) {
647                 nf_conntrack_free(ct);
648                 pr_debug("init conntrack: can't track with proto module\n");
649                 return NULL;
650         }
651
652         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
653
654         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
655         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
656                                  ecache ? ecache->expmask : 0,
657                              GFP_ATOMIC);
658
659         spin_lock_bh(&nf_conntrack_lock);
660         exp = nf_ct_find_expectation(net, tuple);
661         if (exp) {
662                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
663                          ct, exp);
664                 /* Welcome, Mr. Bond.  We've been expecting you... */
665                 __set_bit(IPS_EXPECTED_BIT, &ct->status);
666                 ct->master = exp->master;
667                 if (exp->helper) {
668                         help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
669                         if (help)
670                                 rcu_assign_pointer(help->helper, exp->helper);
671                 }
672
673 #ifdef CONFIG_NF_CONNTRACK_MARK
674                 ct->mark = exp->master->mark;
675 #endif
676 #ifdef CONFIG_NF_CONNTRACK_SECMARK
677                 ct->secmark = exp->master->secmark;
678 #endif
679                 nf_conntrack_get(&ct->master->ct_general);
680                 NF_CT_STAT_INC(net, expect_new);
681         } else {
682                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
683                 NF_CT_STAT_INC(net, new);
684         }
685
686         /* Overload tuple linked list to put us in unconfirmed list. */
687         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
688                        &net->ct.unconfirmed);
689
690         spin_unlock_bh(&nf_conntrack_lock);
691
692         if (exp) {
693                 if (exp->expectfn)
694                         exp->expectfn(ct, exp);
695                 nf_ct_expect_put(exp);
696         }
697
698         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
699 }
700
701 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
702 static inline struct nf_conn *
703 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
704                   struct sk_buff *skb,
705                   unsigned int dataoff,
706                   u_int16_t l3num,
707                   u_int8_t protonum,
708                   struct nf_conntrack_l3proto *l3proto,
709                   struct nf_conntrack_l4proto *l4proto,
710                   int *set_reply,
711                   enum ip_conntrack_info *ctinfo)
712 {
713         struct nf_conntrack_tuple tuple;
714         struct nf_conntrack_tuple_hash *h;
715         struct nf_conn *ct;
716
717         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
718                              dataoff, l3num, protonum, &tuple, l3proto,
719                              l4proto)) {
720                 pr_debug("resolve_normal_ct: Can't get tuple\n");
721                 return NULL;
722         }
723
724         /* look for tuple match */
725         h = nf_conntrack_find_get(net, &tuple);
726         if (!h) {
727                 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
728                                    skb, dataoff);
729                 if (!h)
730                         return NULL;
731                 if (IS_ERR(h))
732                         return (void *)h;
733         }
734         ct = nf_ct_tuplehash_to_ctrack(h);
735
736         /* It exists; we have (non-exclusive) reference. */
737         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
738                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
739                 /* Please set reply bit if this packet OK */
740                 *set_reply = 1;
741         } else {
742                 /* Once we've had two way comms, always ESTABLISHED. */
743                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
744                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
745                         *ctinfo = IP_CT_ESTABLISHED;
746                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
747                         pr_debug("nf_conntrack_in: related packet for %p\n",
748                                  ct);
749                         *ctinfo = IP_CT_RELATED;
750                 } else {
751                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
752                         *ctinfo = IP_CT_NEW;
753                 }
754                 *set_reply = 0;
755         }
756         skb->nfct = &ct->ct_general;
757         skb->nfctinfo = *ctinfo;
758         return ct;
759 }
760
761 unsigned int
762 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
763                 struct sk_buff *skb)
764 {
765         struct nf_conn *ct, *tmpl = NULL;
766         enum ip_conntrack_info ctinfo;
767         struct nf_conntrack_l3proto *l3proto;
768         struct nf_conntrack_l4proto *l4proto;
769         unsigned int dataoff;
770         u_int8_t protonum;
771         int set_reply = 0;
772         int ret;
773
774         if (skb->nfct) {
775                 /* Previously seen (loopback or untracked)?  Ignore. */
776                 tmpl = (struct nf_conn *)skb->nfct;
777                 if (!nf_ct_is_template(tmpl)) {
778                         NF_CT_STAT_INC_ATOMIC(net, ignore);
779                         return NF_ACCEPT;
780                 }
781                 skb->nfct = NULL;
782         }
783
784         /* rcu_read_lock()ed by nf_hook_slow */
785         l3proto = __nf_ct_l3proto_find(pf);
786         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
787                                    &dataoff, &protonum);
788         if (ret <= 0) {
789                 pr_debug("not prepared to track yet or error occured\n");
790                 NF_CT_STAT_INC_ATOMIC(net, error);
791                 NF_CT_STAT_INC_ATOMIC(net, invalid);
792                 ret = -ret;
793                 goto out;
794         }
795
796         l4proto = __nf_ct_l4proto_find(pf, protonum);
797
798         /* It may be an special packet, error, unclean...
799          * inverse of the return code tells to the netfilter
800          * core what to do with the packet. */
801         if (l4proto->error != NULL) {
802                 ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum);
803                 if (ret <= 0) {
804                         NF_CT_STAT_INC_ATOMIC(net, error);
805                         NF_CT_STAT_INC_ATOMIC(net, invalid);
806                         ret = -ret;
807                         goto out;
808                 }
809         }
810
811         ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
812                                l3proto, l4proto, &set_reply, &ctinfo);
813         if (!ct) {
814                 /* Not valid part of a connection */
815                 NF_CT_STAT_INC_ATOMIC(net, invalid);
816                 ret = NF_ACCEPT;
817                 goto out;
818         }
819
820         if (IS_ERR(ct)) {
821                 /* Too stressed to deal. */
822                 NF_CT_STAT_INC_ATOMIC(net, drop);
823                 ret = NF_DROP;
824                 goto out;
825         }
826
827         NF_CT_ASSERT(skb->nfct);
828
829         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
830         if (ret <= 0) {
831                 /* Invalid: inverse of the return code tells
832                  * the netfilter core what to do */
833                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
834                 nf_conntrack_put(skb->nfct);
835                 skb->nfct = NULL;
836                 NF_CT_STAT_INC_ATOMIC(net, invalid);
837                 if (ret == -NF_DROP)
838                         NF_CT_STAT_INC_ATOMIC(net, drop);
839                 ret = -ret;
840                 goto out;
841         }
842
843         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
844                 nf_conntrack_event_cache(IPCT_REPLY, ct);
845 out:
846         if (tmpl)
847                 nf_ct_put(tmpl);
848
849         return ret;
850 }
851 EXPORT_SYMBOL_GPL(nf_conntrack_in);
852
853 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
854                           const struct nf_conntrack_tuple *orig)
855 {
856         bool ret;
857
858         rcu_read_lock();
859         ret = nf_ct_invert_tuple(inverse, orig,
860                                  __nf_ct_l3proto_find(orig->src.l3num),
861                                  __nf_ct_l4proto_find(orig->src.l3num,
862                                                       orig->dst.protonum));
863         rcu_read_unlock();
864         return ret;
865 }
866 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
867
868 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
869    implicitly racy: see __nf_conntrack_confirm */
870 void nf_conntrack_alter_reply(struct nf_conn *ct,
871                               const struct nf_conntrack_tuple *newreply)
872 {
873         struct nf_conn_help *help = nfct_help(ct);
874
875         /* Should be unconfirmed, so not in hash table yet */
876         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
877
878         pr_debug("Altering reply tuple of %p to ", ct);
879         nf_ct_dump_tuple(newreply);
880
881         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
882         if (ct->master || (help && !hlist_empty(&help->expectations)))
883                 return;
884
885         rcu_read_lock();
886         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
887         rcu_read_unlock();
888 }
889 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
890
891 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
892 void __nf_ct_refresh_acct(struct nf_conn *ct,
893                           enum ip_conntrack_info ctinfo,
894                           const struct sk_buff *skb,
895                           unsigned long extra_jiffies,
896                           int do_acct)
897 {
898         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
899         NF_CT_ASSERT(skb);
900
901         /* Only update if this is not a fixed timeout */
902         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
903                 goto acct;
904
905         /* If not in hash table, timer will not be active yet */
906         if (!nf_ct_is_confirmed(ct)) {
907                 ct->timeout.expires = extra_jiffies;
908         } else {
909                 unsigned long newtime = jiffies + extra_jiffies;
910
911                 /* Only update the timeout if the new timeout is at least
912                    HZ jiffies from the old timeout. Need del_timer for race
913                    avoidance (may already be dying). */
914                 if (newtime - ct->timeout.expires >= HZ)
915                         mod_timer_pending(&ct->timeout, newtime);
916         }
917
918 acct:
919         if (do_acct) {
920                 struct nf_conn_counter *acct;
921
922                 acct = nf_conn_acct_find(ct);
923                 if (acct) {
924                         spin_lock_bh(&ct->lock);
925                         acct[CTINFO2DIR(ctinfo)].packets++;
926                         acct[CTINFO2DIR(ctinfo)].bytes +=
927                                 skb->len - skb_network_offset(skb);
928                         spin_unlock_bh(&ct->lock);
929                 }
930         }
931 }
932 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
933
934 bool __nf_ct_kill_acct(struct nf_conn *ct,
935                        enum ip_conntrack_info ctinfo,
936                        const struct sk_buff *skb,
937                        int do_acct)
938 {
939         if (do_acct) {
940                 struct nf_conn_counter *acct;
941
942                 acct = nf_conn_acct_find(ct);
943                 if (acct) {
944                         spin_lock_bh(&ct->lock);
945                         acct[CTINFO2DIR(ctinfo)].packets++;
946                         acct[CTINFO2DIR(ctinfo)].bytes +=
947                                 skb->len - skb_network_offset(skb);
948                         spin_unlock_bh(&ct->lock);
949                 }
950         }
951
952         if (del_timer(&ct->timeout)) {
953                 ct->timeout.function((unsigned long)ct);
954                 return true;
955         }
956         return false;
957 }
958 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
959
960 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
961
962 #include <linux/netfilter/nfnetlink.h>
963 #include <linux/netfilter/nfnetlink_conntrack.h>
964 #include <linux/mutex.h>
965
966 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
967  * in ip_conntrack_core, since we don't want the protocols to autoload
968  * or depend on ctnetlink */
969 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
970                                const struct nf_conntrack_tuple *tuple)
971 {
972         NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
973         NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
974         return 0;
975
976 nla_put_failure:
977         return -1;
978 }
979 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
980
981 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
982         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
983         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
984 };
985 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
986
987 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
988                                struct nf_conntrack_tuple *t)
989 {
990         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
991                 return -EINVAL;
992
993         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
994         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
995
996         return 0;
997 }
998 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
999
1000 int nf_ct_port_nlattr_tuple_size(void)
1001 {
1002         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1003 }
1004 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1005 #endif
1006
1007 /* Used by ipt_REJECT and ip6t_REJECT. */
1008 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1009 {
1010         struct nf_conn *ct;
1011         enum ip_conntrack_info ctinfo;
1012
1013         /* This ICMP is in reverse direction to the packet which caused it */
1014         ct = nf_ct_get(skb, &ctinfo);
1015         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1016                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
1017         else
1018                 ctinfo = IP_CT_RELATED;
1019
1020         /* Attach to new skbuff, and increment count */
1021         nskb->nfct = &ct->ct_general;
1022         nskb->nfctinfo = ctinfo;
1023         nf_conntrack_get(nskb->nfct);
1024 }
1025
1026 /* Bring out ya dead! */
1027 static struct nf_conn *
1028 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1029                 void *data, unsigned int *bucket)
1030 {
1031         struct nf_conntrack_tuple_hash *h;
1032         struct nf_conn *ct;
1033         struct hlist_nulls_node *n;
1034
1035         spin_lock_bh(&nf_conntrack_lock);
1036         for (; *bucket < net->ct.htable_size; (*bucket)++) {
1037                 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1038                         ct = nf_ct_tuplehash_to_ctrack(h);
1039                         if (iter(ct, data))
1040                                 goto found;
1041                 }
1042         }
1043         hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1044                 ct = nf_ct_tuplehash_to_ctrack(h);
1045                 if (iter(ct, data))
1046                         set_bit(IPS_DYING_BIT, &ct->status);
1047         }
1048         spin_unlock_bh(&nf_conntrack_lock);
1049         return NULL;
1050 found:
1051         atomic_inc(&ct->ct_general.use);
1052         spin_unlock_bh(&nf_conntrack_lock);
1053         return ct;
1054 }
1055
1056 void nf_ct_iterate_cleanup(struct net *net,
1057                            int (*iter)(struct nf_conn *i, void *data),
1058                            void *data)
1059 {
1060         struct nf_conn *ct;
1061         unsigned int bucket = 0;
1062
1063         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1064                 /* Time to push up daises... */
1065                 if (del_timer(&ct->timeout))
1066                         death_by_timeout((unsigned long)ct);
1067                 /* ... else the timer will get him soon. */
1068
1069                 nf_ct_put(ct);
1070         }
1071 }
1072 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1073
1074 struct __nf_ct_flush_report {
1075         u32 pid;
1076         int report;
1077 };
1078
1079 static int kill_report(struct nf_conn *i, void *data)
1080 {
1081         struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1082
1083         /* If we fail to deliver the event, death_by_timeout() will retry */
1084         if (nf_conntrack_event_report(IPCT_DESTROY, i,
1085                                       fr->pid, fr->report) < 0)
1086                 return 1;
1087
1088         /* Avoid the delivery of the destroy event in death_by_timeout(). */
1089         set_bit(IPS_DYING_BIT, &i->status);
1090         return 1;
1091 }
1092
1093 static int kill_all(struct nf_conn *i, void *data)
1094 {
1095         return 1;
1096 }
1097
1098 void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size)
1099 {
1100         if (vmalloced)
1101                 vfree(hash);
1102         else
1103                 free_pages((unsigned long)hash,
1104                            get_order(sizeof(struct hlist_head) * size));
1105 }
1106 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1107
1108 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1109 {
1110         struct __nf_ct_flush_report fr = {
1111                 .pid    = pid,
1112                 .report = report,
1113         };
1114         nf_ct_iterate_cleanup(net, kill_report, &fr);
1115 }
1116 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1117
1118 static void nf_ct_release_dying_list(struct net *net)
1119 {
1120         struct nf_conntrack_tuple_hash *h;
1121         struct nf_conn *ct;
1122         struct hlist_nulls_node *n;
1123
1124         spin_lock_bh(&nf_conntrack_lock);
1125         hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) {
1126                 ct = nf_ct_tuplehash_to_ctrack(h);
1127                 /* never fails to remove them, no listeners at this point */
1128                 nf_ct_kill(ct);
1129         }
1130         spin_unlock_bh(&nf_conntrack_lock);
1131 }
1132
1133 static void nf_conntrack_cleanup_init_net(void)
1134 {
1135         /* wait until all references to nf_conntrack_untracked are dropped */
1136         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1137                 schedule();
1138
1139         nf_conntrack_helper_fini();
1140         nf_conntrack_proto_fini();
1141 }
1142
1143 static void nf_conntrack_cleanup_net(struct net *net)
1144 {
1145  i_see_dead_people:
1146         nf_ct_iterate_cleanup(net, kill_all, NULL);
1147         nf_ct_release_dying_list(net);
1148         if (atomic_read(&net->ct.count) != 0) {
1149                 schedule();
1150                 goto i_see_dead_people;
1151         }
1152
1153         nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1154                              net->ct.htable_size);
1155         nf_conntrack_ecache_fini(net);
1156         nf_conntrack_acct_fini(net);
1157         nf_conntrack_expect_fini(net);
1158         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1159         kfree(net->ct.slabname);
1160         free_percpu(net->ct.stat);
1161 }
1162
1163 /* Mishearing the voices in his head, our hero wonders how he's
1164    supposed to kill the mall. */
1165 void nf_conntrack_cleanup(struct net *net)
1166 {
1167         if (net_eq(net, &init_net))
1168                 rcu_assign_pointer(ip_ct_attach, NULL);
1169
1170         /* This makes sure all current packets have passed through
1171            netfilter framework.  Roll on, two-stage module
1172            delete... */
1173         synchronize_net();
1174
1175         nf_conntrack_cleanup_net(net);
1176
1177         if (net_eq(net, &init_net)) {
1178                 rcu_assign_pointer(nf_ct_destroy, NULL);
1179                 nf_conntrack_cleanup_init_net();
1180         }
1181 }
1182
1183 void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls)
1184 {
1185         struct hlist_nulls_head *hash;
1186         unsigned int nr_slots, i;
1187         size_t sz;
1188
1189         *vmalloced = 0;
1190
1191         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1192         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1193         sz = nr_slots * sizeof(struct hlist_nulls_head);
1194         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1195                                         get_order(sz));
1196         if (!hash) {
1197                 *vmalloced = 1;
1198                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1199                 hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
1200         }
1201
1202         if (hash && nulls)
1203                 for (i = 0; i < nr_slots; i++)
1204                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1205
1206         return hash;
1207 }
1208 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1209
1210 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1211 {
1212         int i, bucket, vmalloced, old_vmalloced;
1213         unsigned int hashsize, old_size;
1214         struct hlist_nulls_head *hash, *old_hash;
1215         struct nf_conntrack_tuple_hash *h;
1216
1217         if (current->nsproxy->net_ns != &init_net)
1218                 return -EOPNOTSUPP;
1219
1220         /* On boot, we can set this without any fancy locking. */
1221         if (!nf_conntrack_htable_size)
1222                 return param_set_uint(val, kp);
1223
1224         hashsize = simple_strtoul(val, NULL, 0);
1225         if (!hashsize)
1226                 return -EINVAL;
1227
1228         hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1);
1229         if (!hash)
1230                 return -ENOMEM;
1231
1232         /* Lookups in the old hash might happen in parallel, which means we
1233          * might get false negatives during connection lookup. New connections
1234          * created because of a false negative won't make it into the hash
1235          * though since that required taking the lock.
1236          */
1237         spin_lock_bh(&nf_conntrack_lock);
1238         for (i = 0; i < init_net.ct.htable_size; i++) {
1239                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1240                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1241                                         struct nf_conntrack_tuple_hash, hnnode);
1242                         hlist_nulls_del_rcu(&h->hnnode);
1243                         bucket = __hash_conntrack(&h->tuple, hashsize,
1244                                                   nf_conntrack_hash_rnd);
1245                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1246                 }
1247         }
1248         old_size = init_net.ct.htable_size;
1249         old_vmalloced = init_net.ct.hash_vmalloc;
1250         old_hash = init_net.ct.hash;
1251
1252         init_net.ct.htable_size = nf_conntrack_htable_size = hashsize;
1253         init_net.ct.hash_vmalloc = vmalloced;
1254         init_net.ct.hash = hash;
1255         spin_unlock_bh(&nf_conntrack_lock);
1256
1257         nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1258         return 0;
1259 }
1260 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1261
1262 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1263                   &nf_conntrack_htable_size, 0600);
1264
1265 static int nf_conntrack_init_init_net(void)
1266 {
1267         int max_factor = 8;
1268         int ret;
1269
1270         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1271          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1272         if (!nf_conntrack_htable_size) {
1273                 nf_conntrack_htable_size
1274                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1275                            / sizeof(struct hlist_head));
1276                 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1277                         nf_conntrack_htable_size = 16384;
1278                 if (nf_conntrack_htable_size < 32)
1279                         nf_conntrack_htable_size = 32;
1280
1281                 /* Use a max. factor of four by default to get the same max as
1282                  * with the old struct list_heads. When a table size is given
1283                  * we use the old value of 8 to avoid reducing the max.
1284                  * entries. */
1285                 max_factor = 4;
1286         }
1287         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1288
1289         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1290                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1291                nf_conntrack_max);
1292
1293         ret = nf_conntrack_proto_init();
1294         if (ret < 0)
1295                 goto err_proto;
1296
1297         ret = nf_conntrack_helper_init();
1298         if (ret < 0)
1299                 goto err_helper;
1300
1301         /* Set up fake conntrack: to never be deleted, not in any hashes */
1302 #ifdef CONFIG_NET_NS
1303         nf_conntrack_untracked.ct_net = &init_net;
1304 #endif
1305         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1306         /*  - and look it like as a confirmed connection */
1307         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1308
1309         return 0;
1310
1311 err_helper:
1312         nf_conntrack_proto_fini();
1313 err_proto:
1314         return ret;
1315 }
1316
1317 /*
1318  * We need to use special "null" values, not used in hash table
1319  */
1320 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1321 #define DYING_NULLS_VAL         ((1<<30)+1)
1322
1323 static int nf_conntrack_init_net(struct net *net)
1324 {
1325         int ret;
1326
1327         atomic_set(&net->ct.count, 0);
1328         INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1329         INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1330         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1331         if (!net->ct.stat) {
1332                 ret = -ENOMEM;
1333                 goto err_stat;
1334         }
1335
1336         net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1337         if (!net->ct.slabname) {
1338                 ret = -ENOMEM;
1339                 goto err_slabname;
1340         }
1341
1342         net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1343                                                         sizeof(struct nf_conn), 0,
1344                                                         SLAB_DESTROY_BY_RCU, NULL);
1345         if (!net->ct.nf_conntrack_cachep) {
1346                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1347                 ret = -ENOMEM;
1348                 goto err_cache;
1349         }
1350
1351         net->ct.htable_size = nf_conntrack_htable_size;
1352         net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size,
1353                                              &net->ct.hash_vmalloc, 1);
1354         if (!net->ct.hash) {
1355                 ret = -ENOMEM;
1356                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1357                 goto err_hash;
1358         }
1359         ret = nf_conntrack_expect_init(net);
1360         if (ret < 0)
1361                 goto err_expect;
1362         ret = nf_conntrack_acct_init(net);
1363         if (ret < 0)
1364                 goto err_acct;
1365         ret = nf_conntrack_ecache_init(net);
1366         if (ret < 0)
1367                 goto err_ecache;
1368
1369         return 0;
1370
1371 err_ecache:
1372         nf_conntrack_acct_fini(net);
1373 err_acct:
1374         nf_conntrack_expect_fini(net);
1375 err_expect:
1376         nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1377                              net->ct.htable_size);
1378 err_hash:
1379         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1380 err_cache:
1381         kfree(net->ct.slabname);
1382 err_slabname:
1383         free_percpu(net->ct.stat);
1384 err_stat:
1385         return ret;
1386 }
1387
1388 s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
1389                         enum ip_conntrack_dir dir,
1390                         u32 seq);
1391 EXPORT_SYMBOL_GPL(nf_ct_nat_offset);
1392
1393 int nf_conntrack_init(struct net *net)
1394 {
1395         int ret;
1396
1397         if (net_eq(net, &init_net)) {
1398                 ret = nf_conntrack_init_init_net();
1399                 if (ret < 0)
1400                         goto out_init_net;
1401         }
1402         ret = nf_conntrack_init_net(net);
1403         if (ret < 0)
1404                 goto out_net;
1405
1406         if (net_eq(net, &init_net)) {
1407                 /* For use by REJECT target */
1408                 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1409                 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1410
1411                 /* Howto get NAT offsets */
1412                 rcu_assign_pointer(nf_ct_nat_offset, NULL);
1413         }
1414         return 0;
1415
1416 out_net:
1417         if (net_eq(net, &init_net))
1418                 nf_conntrack_cleanup_init_net();
1419 out_init_net:
1420         return ret;
1421 }