1 /* Expectation handling for nf_conntrack. */
3 /* (C) 1999-2001 Paul `Rusty' Russell
4 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
5 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/types.h>
13 #include <linux/netfilter.h>
14 #include <linux/skbuff.h>
15 #include <linux/proc_fs.h>
16 #include <linux/seq_file.h>
17 #include <linux/stddef.h>
18 #include <linux/slab.h>
19 #include <linux/err.h>
20 #include <linux/percpu.h>
21 #include <linux/kernel.h>
22 #include <linux/jhash.h>
23 #include <linux/moduleparam.h>
24 #include <linux/export.h>
25 #include <net/net_namespace.h>
27 #include <net/netfilter/nf_conntrack.h>
28 #include <net/netfilter/nf_conntrack_core.h>
29 #include <net/netfilter/nf_conntrack_expect.h>
30 #include <net/netfilter/nf_conntrack_helper.h>
31 #include <net/netfilter/nf_conntrack_tuple.h>
32 #include <net/netfilter/nf_conntrack_zones.h>
34 unsigned int nf_ct_expect_hsize __read_mostly;
35 EXPORT_SYMBOL_GPL(nf_ct_expect_hsize);
37 unsigned int nf_ct_expect_max __read_mostly;
39 static struct kmem_cache *nf_ct_expect_cachep __read_mostly;
41 /* nf_conntrack_expect helper functions */
42 void nf_ct_unlink_expect_report(struct nf_conntrack_expect *exp,
45 struct nf_conn_help *master_help = nfct_help(exp->master);
46 struct net *net = nf_ct_exp_net(exp);
48 NF_CT_ASSERT(master_help);
49 NF_CT_ASSERT(!timer_pending(&exp->timeout));
51 hlist_del_rcu(&exp->hnode);
52 net->ct.expect_count--;
54 hlist_del(&exp->lnode);
55 master_help->expecting[exp->class]--;
57 nf_ct_expect_event_report(IPEXP_DESTROY, exp, pid, report);
58 nf_ct_expect_put(exp);
60 NF_CT_STAT_INC(net, expect_delete);
62 EXPORT_SYMBOL_GPL(nf_ct_unlink_expect_report);
64 static void nf_ct_expectation_timed_out(unsigned long ul_expect)
66 struct nf_conntrack_expect *exp = (void *)ul_expect;
68 spin_lock_bh(&nf_conntrack_lock);
69 nf_ct_unlink_expect(exp);
70 spin_unlock_bh(&nf_conntrack_lock);
71 nf_ct_expect_put(exp);
74 static unsigned int nf_ct_expect_dst_hash(const struct nf_conntrack_tuple *tuple)
78 if (unlikely(!nf_conntrack_hash_rnd)) {
79 init_nf_conntrack_hash_rnd();
82 hash = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),
83 (((tuple->dst.protonum ^ tuple->src.l3num) << 16) |
84 (__force __u16)tuple->dst.u.all) ^ nf_conntrack_hash_rnd);
85 return ((u64)hash * nf_ct_expect_hsize) >> 32;
88 struct nf_conntrack_expect *
89 __nf_ct_expect_find(struct net *net, u16 zone,
90 const struct nf_conntrack_tuple *tuple)
92 struct nf_conntrack_expect *i;
96 if (!net->ct.expect_count)
99 h = nf_ct_expect_dst_hash(tuple);
100 hlist_for_each_entry_rcu(i, n, &net->ct.expect_hash[h], hnode) {
101 if (nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask) &&
102 nf_ct_zone(i->master) == zone)
107 EXPORT_SYMBOL_GPL(__nf_ct_expect_find);
109 /* Just find a expectation corresponding to a tuple. */
110 struct nf_conntrack_expect *
111 nf_ct_expect_find_get(struct net *net, u16 zone,
112 const struct nf_conntrack_tuple *tuple)
114 struct nf_conntrack_expect *i;
117 i = __nf_ct_expect_find(net, zone, tuple);
118 if (i && !atomic_inc_not_zero(&i->use))
124 EXPORT_SYMBOL_GPL(nf_ct_expect_find_get);
126 /* If an expectation for this connection is found, it gets delete from
127 * global list then returned. */
128 struct nf_conntrack_expect *
129 nf_ct_find_expectation(struct net *net, u16 zone,
130 const struct nf_conntrack_tuple *tuple)
132 struct nf_conntrack_expect *i, *exp = NULL;
133 struct hlist_node *n;
136 if (!net->ct.expect_count)
139 h = nf_ct_expect_dst_hash(tuple);
140 hlist_for_each_entry(i, n, &net->ct.expect_hash[h], hnode) {
141 if (!(i->flags & NF_CT_EXPECT_INACTIVE) &&
142 nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask) &&
143 nf_ct_zone(i->master) == zone) {
151 /* If master is not in hash table yet (ie. packet hasn't left
152 this machine yet), how can other end know about expected?
153 Hence these are not the droids you are looking for (if
154 master ct never got confirmed, we'd hold a reference to it
155 and weird things would happen to future packets). */
156 if (!nf_ct_is_confirmed(exp->master))
159 if (exp->flags & NF_CT_EXPECT_PERMANENT) {
160 atomic_inc(&exp->use);
162 } else if (del_timer(&exp->timeout)) {
163 nf_ct_unlink_expect(exp);
170 /* delete all expectations for this conntrack */
171 void nf_ct_remove_expectations(struct nf_conn *ct)
173 struct nf_conn_help *help = nfct_help(ct);
174 struct nf_conntrack_expect *exp;
175 struct hlist_node *n, *next;
177 /* Optimization: most connection never expect any others. */
181 hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) {
182 if (del_timer(&exp->timeout)) {
183 nf_ct_unlink_expect(exp);
184 nf_ct_expect_put(exp);
188 EXPORT_SYMBOL_GPL(nf_ct_remove_expectations);
190 /* Would two expected things clash? */
191 static inline int expect_clash(const struct nf_conntrack_expect *a,
192 const struct nf_conntrack_expect *b)
194 /* Part covered by intersection of masks must be unequal,
195 otherwise they clash */
196 struct nf_conntrack_tuple_mask intersect_mask;
199 intersect_mask.src.u.all = a->mask.src.u.all & b->mask.src.u.all;
201 for (count = 0; count < NF_CT_TUPLE_L3SIZE; count++){
202 intersect_mask.src.u3.all[count] =
203 a->mask.src.u3.all[count] & b->mask.src.u3.all[count];
206 return nf_ct_tuple_mask_cmp(&a->tuple, &b->tuple, &intersect_mask);
209 static inline int expect_matches(const struct nf_conntrack_expect *a,
210 const struct nf_conntrack_expect *b)
212 return a->master == b->master && a->class == b->class &&
213 nf_ct_tuple_equal(&a->tuple, &b->tuple) &&
214 nf_ct_tuple_mask_equal(&a->mask, &b->mask) &&
215 nf_ct_zone(a->master) == nf_ct_zone(b->master);
218 /* Generally a bad idea to call this: could have matched already. */
219 void nf_ct_unexpect_related(struct nf_conntrack_expect *exp)
221 spin_lock_bh(&nf_conntrack_lock);
222 if (del_timer(&exp->timeout)) {
223 nf_ct_unlink_expect(exp);
224 nf_ct_expect_put(exp);
226 spin_unlock_bh(&nf_conntrack_lock);
228 EXPORT_SYMBOL_GPL(nf_ct_unexpect_related);
230 /* We don't increase the master conntrack refcount for non-fulfilled
231 * conntracks. During the conntrack destruction, the expectations are
232 * always killed before the conntrack itself */
233 struct nf_conntrack_expect *nf_ct_expect_alloc(struct nf_conn *me)
235 struct nf_conntrack_expect *new;
237 new = kmem_cache_alloc(nf_ct_expect_cachep, GFP_ATOMIC);
242 atomic_set(&new->use, 1);
245 EXPORT_SYMBOL_GPL(nf_ct_expect_alloc);
247 void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class,
249 const union nf_inet_addr *saddr,
250 const union nf_inet_addr *daddr,
251 u_int8_t proto, const __be16 *src, const __be16 *dst)
255 if (family == AF_INET)
262 exp->expectfn = NULL;
264 exp->tuple.src.l3num = family;
265 exp->tuple.dst.protonum = proto;
268 memcpy(&exp->tuple.src.u3, saddr, len);
269 if (sizeof(exp->tuple.src.u3) > len)
270 /* address needs to be cleared for nf_ct_tuple_equal */
271 memset((void *)&exp->tuple.src.u3 + len, 0x00,
272 sizeof(exp->tuple.src.u3) - len);
273 memset(&exp->mask.src.u3, 0xFF, len);
274 if (sizeof(exp->mask.src.u3) > len)
275 memset((void *)&exp->mask.src.u3 + len, 0x00,
276 sizeof(exp->mask.src.u3) - len);
278 memset(&exp->tuple.src.u3, 0x00, sizeof(exp->tuple.src.u3));
279 memset(&exp->mask.src.u3, 0x00, sizeof(exp->mask.src.u3));
283 exp->tuple.src.u.all = *src;
284 exp->mask.src.u.all = htons(0xFFFF);
286 exp->tuple.src.u.all = 0;
287 exp->mask.src.u.all = 0;
290 memcpy(&exp->tuple.dst.u3, daddr, len);
291 if (sizeof(exp->tuple.dst.u3) > len)
292 /* address needs to be cleared for nf_ct_tuple_equal */
293 memset((void *)&exp->tuple.dst.u3 + len, 0x00,
294 sizeof(exp->tuple.dst.u3) - len);
296 exp->tuple.dst.u.all = *dst;
298 EXPORT_SYMBOL_GPL(nf_ct_expect_init);
300 static void nf_ct_expect_free_rcu(struct rcu_head *head)
302 struct nf_conntrack_expect *exp;
304 exp = container_of(head, struct nf_conntrack_expect, rcu);
305 kmem_cache_free(nf_ct_expect_cachep, exp);
308 void nf_ct_expect_put(struct nf_conntrack_expect *exp)
310 if (atomic_dec_and_test(&exp->use))
311 call_rcu(&exp->rcu, nf_ct_expect_free_rcu);
313 EXPORT_SYMBOL_GPL(nf_ct_expect_put);
315 static int nf_ct_expect_insert(struct nf_conntrack_expect *exp)
317 struct nf_conn_help *master_help = nfct_help(exp->master);
318 struct nf_conntrack_helper *helper;
319 struct net *net = nf_ct_exp_net(exp);
320 unsigned int h = nf_ct_expect_dst_hash(&exp->tuple);
322 /* two references : one for hash insert, one for the timer */
323 atomic_add(2, &exp->use);
325 hlist_add_head(&exp->lnode, &master_help->expectations);
326 master_help->expecting[exp->class]++;
328 hlist_add_head_rcu(&exp->hnode, &net->ct.expect_hash[h]);
329 net->ct.expect_count++;
331 setup_timer(&exp->timeout, nf_ct_expectation_timed_out,
333 helper = rcu_dereference_protected(master_help->helper,
334 lockdep_is_held(&nf_conntrack_lock));
336 exp->timeout.expires = jiffies +
337 helper->expect_policy[exp->class].timeout * HZ;
339 add_timer(&exp->timeout);
341 NF_CT_STAT_INC(net, expect_create);
345 /* Race with expectations being used means we could have none to find; OK. */
346 static void evict_oldest_expect(struct nf_conn *master,
347 struct nf_conntrack_expect *new)
349 struct nf_conn_help *master_help = nfct_help(master);
350 struct nf_conntrack_expect *exp, *last = NULL;
351 struct hlist_node *n;
353 hlist_for_each_entry(exp, n, &master_help->expectations, lnode) {
354 if (exp->class == new->class)
358 if (last && del_timer(&last->timeout)) {
359 nf_ct_unlink_expect(last);
360 nf_ct_expect_put(last);
364 static inline int refresh_timer(struct nf_conntrack_expect *i)
366 struct nf_conn_help *master_help = nfct_help(i->master);
367 const struct nf_conntrack_expect_policy *p;
369 if (!del_timer(&i->timeout))
372 p = &rcu_dereference_protected(
374 lockdep_is_held(&nf_conntrack_lock)
375 )->expect_policy[i->class];
376 i->timeout.expires = jiffies + p->timeout * HZ;
377 add_timer(&i->timeout);
381 static inline int __nf_ct_expect_check(struct nf_conntrack_expect *expect)
383 const struct nf_conntrack_expect_policy *p;
384 struct nf_conntrack_expect *i;
385 struct nf_conn *master = expect->master;
386 struct nf_conn_help *master_help = nfct_help(master);
387 struct nf_conntrack_helper *helper;
388 struct net *net = nf_ct_exp_net(expect);
389 struct hlist_node *n;
397 h = nf_ct_expect_dst_hash(&expect->tuple);
398 hlist_for_each_entry(i, n, &net->ct.expect_hash[h], hnode) {
399 if (expect_matches(i, expect)) {
400 /* Refresh timer: if it's dying, ignore.. */
401 if (refresh_timer(i)) {
405 } else if (expect_clash(i, expect)) {
410 /* Will be over limit? */
411 helper = rcu_dereference_protected(master_help->helper,
412 lockdep_is_held(&nf_conntrack_lock));
414 p = &helper->expect_policy[expect->class];
415 if (p->max_expected &&
416 master_help->expecting[expect->class] >= p->max_expected) {
417 evict_oldest_expect(master, expect);
418 if (master_help->expecting[expect->class]
419 >= p->max_expected) {
426 if (net->ct.expect_count >= nf_ct_expect_max) {
427 net_warn_ratelimited("nf_conntrack: expectation table full\n");
434 int nf_ct_expect_related_report(struct nf_conntrack_expect *expect,
439 spin_lock_bh(&nf_conntrack_lock);
440 ret = __nf_ct_expect_check(expect);
444 ret = nf_ct_expect_insert(expect);
447 spin_unlock_bh(&nf_conntrack_lock);
448 nf_ct_expect_event_report(IPEXP_NEW, expect, pid, report);
451 spin_unlock_bh(&nf_conntrack_lock);
454 EXPORT_SYMBOL_GPL(nf_ct_expect_related_report);
456 #ifdef CONFIG_NF_CONNTRACK_PROCFS
457 struct ct_expect_iter_state {
458 struct seq_net_private p;
462 static struct hlist_node *ct_expect_get_first(struct seq_file *seq)
464 struct net *net = seq_file_net(seq);
465 struct ct_expect_iter_state *st = seq->private;
466 struct hlist_node *n;
468 for (st->bucket = 0; st->bucket < nf_ct_expect_hsize; st->bucket++) {
469 n = rcu_dereference(hlist_first_rcu(&net->ct.expect_hash[st->bucket]));
476 static struct hlist_node *ct_expect_get_next(struct seq_file *seq,
477 struct hlist_node *head)
479 struct net *net = seq_file_net(seq);
480 struct ct_expect_iter_state *st = seq->private;
482 head = rcu_dereference(hlist_next_rcu(head));
483 while (head == NULL) {
484 if (++st->bucket >= nf_ct_expect_hsize)
486 head = rcu_dereference(hlist_first_rcu(&net->ct.expect_hash[st->bucket]));
491 static struct hlist_node *ct_expect_get_idx(struct seq_file *seq, loff_t pos)
493 struct hlist_node *head = ct_expect_get_first(seq);
496 while (pos && (head = ct_expect_get_next(seq, head)))
498 return pos ? NULL : head;
501 static void *exp_seq_start(struct seq_file *seq, loff_t *pos)
505 return ct_expect_get_idx(seq, *pos);
508 static void *exp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
511 return ct_expect_get_next(seq, v);
514 static void exp_seq_stop(struct seq_file *seq, void *v)
520 static int exp_seq_show(struct seq_file *s, void *v)
522 struct nf_conntrack_expect *expect;
523 struct nf_conntrack_helper *helper;
524 struct hlist_node *n = v;
527 expect = hlist_entry(n, struct nf_conntrack_expect, hnode);
529 if (expect->timeout.function)
530 seq_printf(s, "%ld ", timer_pending(&expect->timeout)
531 ? (long)(expect->timeout.expires - jiffies)/HZ : 0);
534 seq_printf(s, "l3proto = %u proto=%u ",
535 expect->tuple.src.l3num,
536 expect->tuple.dst.protonum);
537 print_tuple(s, &expect->tuple,
538 __nf_ct_l3proto_find(expect->tuple.src.l3num),
539 __nf_ct_l4proto_find(expect->tuple.src.l3num,
540 expect->tuple.dst.protonum));
542 if (expect->flags & NF_CT_EXPECT_PERMANENT) {
543 seq_printf(s, "PERMANENT");
546 if (expect->flags & NF_CT_EXPECT_INACTIVE) {
547 seq_printf(s, "%sINACTIVE", delim);
550 if (expect->flags & NF_CT_EXPECT_USERSPACE)
551 seq_printf(s, "%sUSERSPACE", delim);
553 helper = rcu_dereference(nfct_help(expect->master)->helper);
555 seq_printf(s, "%s%s", expect->flags ? " " : "", helper->name);
556 if (helper->expect_policy[expect->class].name)
558 helper->expect_policy[expect->class].name);
561 return seq_putc(s, '\n');
564 static const struct seq_operations exp_seq_ops = {
565 .start = exp_seq_start,
566 .next = exp_seq_next,
567 .stop = exp_seq_stop,
571 static int exp_open(struct inode *inode, struct file *file)
573 return seq_open_net(inode, file, &exp_seq_ops,
574 sizeof(struct ct_expect_iter_state));
577 static const struct file_operations exp_file_ops = {
578 .owner = THIS_MODULE,
582 .release = seq_release_net,
584 #endif /* CONFIG_NF_CONNTRACK_PROCFS */
586 static int exp_proc_init(struct net *net)
588 #ifdef CONFIG_NF_CONNTRACK_PROCFS
589 struct proc_dir_entry *proc;
591 proc = proc_net_fops_create(net, "nf_conntrack_expect", 0440, &exp_file_ops);
594 #endif /* CONFIG_NF_CONNTRACK_PROCFS */
598 static void exp_proc_remove(struct net *net)
600 #ifdef CONFIG_NF_CONNTRACK_PROCFS
601 proc_net_remove(net, "nf_conntrack_expect");
602 #endif /* CONFIG_NF_CONNTRACK_PROCFS */
605 module_param_named(expect_hashsize, nf_ct_expect_hsize, uint, 0400);
607 int nf_conntrack_expect_init(struct net *net)
611 if (net_eq(net, &init_net)) {
612 if (!nf_ct_expect_hsize) {
613 nf_ct_expect_hsize = net->ct.htable_size / 256;
614 if (!nf_ct_expect_hsize)
615 nf_ct_expect_hsize = 1;
617 nf_ct_expect_max = nf_ct_expect_hsize * 4;
620 net->ct.expect_count = 0;
621 net->ct.expect_hash = nf_ct_alloc_hashtable(&nf_ct_expect_hsize, 0);
622 if (net->ct.expect_hash == NULL)
625 if (net_eq(net, &init_net)) {
626 nf_ct_expect_cachep = kmem_cache_create("nf_conntrack_expect",
627 sizeof(struct nf_conntrack_expect),
629 if (!nf_ct_expect_cachep)
633 err = exp_proc_init(net);
640 if (net_eq(net, &init_net))
641 kmem_cache_destroy(nf_ct_expect_cachep);
643 nf_ct_free_hashtable(net->ct.expect_hash, nf_ct_expect_hsize);
648 void nf_conntrack_expect_fini(struct net *net)
650 exp_proc_remove(net);
651 if (net_eq(net, &init_net)) {
652 rcu_barrier(); /* Wait for call_rcu() before destroy */
653 kmem_cache_destroy(nf_ct_expect_cachep);
655 nf_ct_free_hashtable(net->ct.expect_hash, nf_ct_expect_hsize);