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>
23 #include <net/netfilter/nf_conntrack.h>
24 #include <net/netfilter/nf_conntrack_core.h>
25 #include <net/netfilter/nf_conntrack_expect.h>
26 #include <net/netfilter/nf_conntrack_helper.h>
27 #include <net/netfilter/nf_conntrack_tuple.h>
29 LIST_HEAD(nf_conntrack_expect_list);
30 EXPORT_SYMBOL_GPL(nf_conntrack_expect_list);
32 kmem_cache_t *nf_conntrack_expect_cachep __read_mostly;
33 static unsigned int nf_conntrack_expect_next_id;
35 /* nf_conntrack_expect helper functions */
36 void nf_ct_unlink_expect(struct nf_conntrack_expect *exp)
38 struct nf_conn_help *master_help = nfct_help(exp->master);
40 NF_CT_ASSERT(master_help);
41 NF_CT_ASSERT(!timer_pending(&exp->timeout));
44 NF_CT_STAT_INC(expect_delete);
45 master_help->expecting--;
46 nf_conntrack_expect_put(exp);
48 EXPORT_SYMBOL_GPL(nf_ct_unlink_expect);
50 static void expectation_timed_out(unsigned long ul_expect)
52 struct nf_conntrack_expect *exp = (void *)ul_expect;
54 write_lock_bh(&nf_conntrack_lock);
55 nf_ct_unlink_expect(exp);
56 write_unlock_bh(&nf_conntrack_lock);
57 nf_conntrack_expect_put(exp);
60 struct nf_conntrack_expect *
61 __nf_conntrack_expect_find(const struct nf_conntrack_tuple *tuple)
63 struct nf_conntrack_expect *i;
65 list_for_each_entry(i, &nf_conntrack_expect_list, list) {
66 if (nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask))
71 EXPORT_SYMBOL_GPL(__nf_conntrack_expect_find);
73 /* Just find a expectation corresponding to a tuple. */
74 struct nf_conntrack_expect *
75 nf_conntrack_expect_find_get(const struct nf_conntrack_tuple *tuple)
77 struct nf_conntrack_expect *i;
79 read_lock_bh(&nf_conntrack_lock);
80 i = __nf_conntrack_expect_find(tuple);
83 read_unlock_bh(&nf_conntrack_lock);
87 EXPORT_SYMBOL_GPL(nf_conntrack_expect_find_get);
89 /* If an expectation for this connection is found, it gets delete from
90 * global list then returned. */
91 struct nf_conntrack_expect *
92 find_expectation(const struct nf_conntrack_tuple *tuple)
94 struct nf_conntrack_expect *i;
96 list_for_each_entry(i, &nf_conntrack_expect_list, list) {
97 /* If master is not in hash table yet (ie. packet hasn't left
98 this machine yet), how can other end know about expected?
99 Hence these are not the droids you are looking for (if
100 master ct never got confirmed, we'd hold a reference to it
101 and weird things would happen to future packets). */
102 if (nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask)
103 && nf_ct_is_confirmed(i->master)) {
104 if (i->flags & NF_CT_EXPECT_PERMANENT) {
107 } else if (del_timer(&i->timeout)) {
108 nf_ct_unlink_expect(i);
116 /* delete all expectations for this conntrack */
117 void nf_ct_remove_expectations(struct nf_conn *ct)
119 struct nf_conntrack_expect *i, *tmp;
120 struct nf_conn_help *help = nfct_help(ct);
122 /* Optimization: most connection never expect any others. */
123 if (!help || help->expecting == 0)
126 list_for_each_entry_safe(i, tmp, &nf_conntrack_expect_list, list) {
127 if (i->master == ct && del_timer(&i->timeout)) {
128 nf_ct_unlink_expect(i);
129 nf_conntrack_expect_put(i);
133 EXPORT_SYMBOL_GPL(nf_ct_remove_expectations);
135 /* Would two expected things clash? */
136 static inline int expect_clash(const struct nf_conntrack_expect *a,
137 const struct nf_conntrack_expect *b)
139 /* Part covered by intersection of masks must be unequal,
140 otherwise they clash */
141 struct nf_conntrack_tuple intersect_mask;
144 intersect_mask.src.l3num = a->mask.src.l3num & b->mask.src.l3num;
145 intersect_mask.src.u.all = a->mask.src.u.all & b->mask.src.u.all;
146 intersect_mask.dst.u.all = a->mask.dst.u.all & b->mask.dst.u.all;
147 intersect_mask.dst.protonum = a->mask.dst.protonum
148 & b->mask.dst.protonum;
150 for (count = 0; count < NF_CT_TUPLE_L3SIZE; count++){
151 intersect_mask.src.u3.all[count] =
152 a->mask.src.u3.all[count] & b->mask.src.u3.all[count];
155 for (count = 0; count < NF_CT_TUPLE_L3SIZE; count++){
156 intersect_mask.dst.u3.all[count] =
157 a->mask.dst.u3.all[count] & b->mask.dst.u3.all[count];
160 return nf_ct_tuple_mask_cmp(&a->tuple, &b->tuple, &intersect_mask);
163 static inline int expect_matches(const struct nf_conntrack_expect *a,
164 const struct nf_conntrack_expect *b)
166 return a->master == b->master
167 && nf_ct_tuple_equal(&a->tuple, &b->tuple)
168 && nf_ct_tuple_equal(&a->mask, &b->mask);
171 /* Generally a bad idea to call this: could have matched already. */
172 void nf_conntrack_unexpect_related(struct nf_conntrack_expect *exp)
174 struct nf_conntrack_expect *i;
176 write_lock_bh(&nf_conntrack_lock);
177 /* choose the the oldest expectation to evict */
178 list_for_each_entry_reverse(i, &nf_conntrack_expect_list, list) {
179 if (expect_matches(i, exp) && del_timer(&i->timeout)) {
180 nf_ct_unlink_expect(i);
181 write_unlock_bh(&nf_conntrack_lock);
182 nf_conntrack_expect_put(i);
186 write_unlock_bh(&nf_conntrack_lock);
188 EXPORT_SYMBOL_GPL(nf_conntrack_unexpect_related);
190 /* We don't increase the master conntrack refcount for non-fulfilled
191 * conntracks. During the conntrack destruction, the expectations are
192 * always killed before the conntrack itself */
193 struct nf_conntrack_expect *nf_conntrack_expect_alloc(struct nf_conn *me)
195 struct nf_conntrack_expect *new;
197 new = kmem_cache_alloc(nf_conntrack_expect_cachep, GFP_ATOMIC);
202 atomic_set(&new->use, 1);
205 EXPORT_SYMBOL_GPL(nf_conntrack_expect_alloc);
207 void nf_conntrack_expect_init(struct nf_conntrack_expect *exp, int family,
208 union nf_conntrack_address *saddr,
209 union nf_conntrack_address *daddr,
210 u_int8_t proto, __be16 *src, __be16 *dst)
214 if (family == AF_INET)
220 exp->expectfn = NULL;
222 exp->tuple.src.l3num = family;
223 exp->tuple.dst.protonum = proto;
224 exp->mask.src.l3num = 0xFFFF;
225 exp->mask.dst.protonum = 0xFF;
228 memcpy(&exp->tuple.src.u3, saddr, len);
229 if (sizeof(exp->tuple.src.u3) > len)
230 /* address needs to be cleared for nf_ct_tuple_equal */
231 memset((void *)&exp->tuple.src.u3 + len, 0x00,
232 sizeof(exp->tuple.src.u3) - len);
233 memset(&exp->mask.src.u3, 0xFF, len);
234 if (sizeof(exp->mask.src.u3) > len)
235 memset((void *)&exp->mask.src.u3 + len, 0x00,
236 sizeof(exp->mask.src.u3) - len);
238 memset(&exp->tuple.src.u3, 0x00, sizeof(exp->tuple.src.u3));
239 memset(&exp->mask.src.u3, 0x00, sizeof(exp->mask.src.u3));
243 memcpy(&exp->tuple.dst.u3, daddr, len);
244 if (sizeof(exp->tuple.dst.u3) > len)
245 /* address needs to be cleared for nf_ct_tuple_equal */
246 memset((void *)&exp->tuple.dst.u3 + len, 0x00,
247 sizeof(exp->tuple.dst.u3) - len);
248 memset(&exp->mask.dst.u3, 0xFF, len);
249 if (sizeof(exp->mask.dst.u3) > len)
250 memset((void *)&exp->mask.dst.u3 + len, 0x00,
251 sizeof(exp->mask.dst.u3) - len);
253 memset(&exp->tuple.dst.u3, 0x00, sizeof(exp->tuple.dst.u3));
254 memset(&exp->mask.dst.u3, 0x00, sizeof(exp->mask.dst.u3));
258 exp->tuple.src.u.all = (__force u16)*src;
259 exp->mask.src.u.all = 0xFFFF;
261 exp->tuple.src.u.all = 0;
262 exp->mask.src.u.all = 0;
266 exp->tuple.dst.u.all = (__force u16)*dst;
267 exp->mask.dst.u.all = 0xFFFF;
269 exp->tuple.dst.u.all = 0;
270 exp->mask.dst.u.all = 0;
273 EXPORT_SYMBOL_GPL(nf_conntrack_expect_init);
275 void nf_conntrack_expect_put(struct nf_conntrack_expect *exp)
277 if (atomic_dec_and_test(&exp->use))
278 kmem_cache_free(nf_conntrack_expect_cachep, exp);
280 EXPORT_SYMBOL_GPL(nf_conntrack_expect_put);
282 static void nf_conntrack_expect_insert(struct nf_conntrack_expect *exp)
284 struct nf_conn_help *master_help = nfct_help(exp->master);
286 atomic_inc(&exp->use);
287 master_help->expecting++;
288 list_add(&exp->list, &nf_conntrack_expect_list);
290 init_timer(&exp->timeout);
291 exp->timeout.data = (unsigned long)exp;
292 exp->timeout.function = expectation_timed_out;
293 exp->timeout.expires = jiffies + master_help->helper->timeout * HZ;
294 add_timer(&exp->timeout);
296 exp->id = ++nf_conntrack_expect_next_id;
297 atomic_inc(&exp->use);
298 NF_CT_STAT_INC(expect_create);
301 /* Race with expectations being used means we could have none to find; OK. */
302 static void evict_oldest_expect(struct nf_conn *master)
304 struct nf_conntrack_expect *i;
306 list_for_each_entry_reverse(i, &nf_conntrack_expect_list, list) {
307 if (i->master == master) {
308 if (del_timer(&i->timeout)) {
309 nf_ct_unlink_expect(i);
310 nf_conntrack_expect_put(i);
317 static inline int refresh_timer(struct nf_conntrack_expect *i)
319 struct nf_conn_help *master_help = nfct_help(i->master);
321 if (!del_timer(&i->timeout))
324 i->timeout.expires = jiffies + master_help->helper->timeout*HZ;
325 add_timer(&i->timeout);
329 int nf_conntrack_expect_related(struct nf_conntrack_expect *expect)
331 struct nf_conntrack_expect *i;
332 struct nf_conn *master = expect->master;
333 struct nf_conn_help *master_help = nfct_help(master);
336 NF_CT_ASSERT(master_help);
338 write_lock_bh(&nf_conntrack_lock);
339 list_for_each_entry(i, &nf_conntrack_expect_list, list) {
340 if (expect_matches(i, expect)) {
341 /* Refresh timer: if it's dying, ignore.. */
342 if (refresh_timer(i)) {
346 } else if (expect_clash(i, expect)) {
351 /* Will be over limit? */
352 if (master_help->helper->max_expected &&
353 master_help->expecting >= master_help->helper->max_expected)
354 evict_oldest_expect(master);
356 nf_conntrack_expect_insert(expect);
357 nf_conntrack_expect_event(IPEXP_NEW, expect);
360 write_unlock_bh(&nf_conntrack_lock);
363 EXPORT_SYMBOL_GPL(nf_conntrack_expect_related);
365 #ifdef CONFIG_PROC_FS
366 static void *exp_seq_start(struct seq_file *s, loff_t *pos)
368 struct list_head *e = &nf_conntrack_expect_list;
371 /* strange seq_file api calls stop even if we fail,
372 * thus we need to grab lock since stop unlocks */
373 read_lock_bh(&nf_conntrack_lock);
378 for (i = 0; i <= *pos; i++) {
380 if (e == &nf_conntrack_expect_list)
386 static void *exp_seq_next(struct seq_file *s, void *v, loff_t *pos)
388 struct list_head *e = v;
393 if (e == &nf_conntrack_expect_list)
399 static void exp_seq_stop(struct seq_file *s, void *v)
401 read_unlock_bh(&nf_conntrack_lock);
404 static int exp_seq_show(struct seq_file *s, void *v)
406 struct nf_conntrack_expect *expect = v;
408 if (expect->timeout.function)
409 seq_printf(s, "%ld ", timer_pending(&expect->timeout)
410 ? (long)(expect->timeout.expires - jiffies)/HZ : 0);
413 seq_printf(s, "l3proto = %u proto=%u ",
414 expect->tuple.src.l3num,
415 expect->tuple.dst.protonum);
416 print_tuple(s, &expect->tuple,
417 __nf_ct_l3proto_find(expect->tuple.src.l3num),
418 __nf_ct_l4proto_find(expect->tuple.src.l3num,
419 expect->tuple.dst.protonum));
420 return seq_putc(s, '\n');
423 static struct seq_operations exp_seq_ops = {
424 .start = exp_seq_start,
425 .next = exp_seq_next,
426 .stop = exp_seq_stop,
430 static int exp_open(struct inode *inode, struct file *file)
432 return seq_open(file, &exp_seq_ops);
435 struct file_operations exp_file_ops = {
436 .owner = THIS_MODULE,
440 .release = seq_release
442 #endif /* CONFIG_PROC_FS */