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