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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_conntrack_zones.h> |
46 | #include <net/netfilter/nf_nat.h> |
47 | #include <net/netfilter/nf_nat_core.h> |
48 | |
49 | #define NF_CONNTRACK_VERSION "0.5.0" |
50 | |
51 | int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, |
52 | enum nf_nat_manip_type manip, |
53 | const struct nlattr *attr) __read_mostly; |
54 | EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); |
55 | |
56 | DEFINE_SPINLOCK(nf_conntrack_lock); |
57 | EXPORT_SYMBOL_GPL(nf_conntrack_lock); |
58 | |
59 | unsigned int nf_conntrack_htable_size __read_mostly; |
60 | EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); |
61 | |
62 | unsigned int nf_conntrack_max __read_mostly; |
63 | EXPORT_SYMBOL_GPL(nf_conntrack_max); |
64 | |
65 | struct nf_conn nf_conntrack_untracked __read_mostly; |
66 | EXPORT_SYMBOL_GPL(nf_conntrack_untracked); |
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 | u16 zone, 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 | zone ^ 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 net *net, u16 zone, |
90 | const struct nf_conntrack_tuple *tuple) |
91 | { |
92 | return __hash_conntrack(tuple, zone, net->ct.htable_size, |
93 | nf_conntrack_hash_rnd); |
94 | } |
95 | |
96 | bool |
97 | nf_ct_get_tuple(const struct sk_buff *skb, |
98 | unsigned int nhoff, |
99 | unsigned int dataoff, |
100 | u_int16_t l3num, |
101 | u_int8_t protonum, |
102 | struct nf_conntrack_tuple *tuple, |
103 | const struct nf_conntrack_l3proto *l3proto, |
104 | const struct nf_conntrack_l4proto *l4proto) |
105 | { |
106 | memset(tuple, 0, sizeof(*tuple)); |
107 | |
108 | tuple->src.l3num = l3num; |
109 | if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) |
110 | return false; |
111 | |
112 | tuple->dst.protonum = protonum; |
113 | tuple->dst.dir = IP_CT_DIR_ORIGINAL; |
114 | |
115 | return l4proto->pkt_to_tuple(skb, dataoff, tuple); |
116 | } |
117 | EXPORT_SYMBOL_GPL(nf_ct_get_tuple); |
118 | |
119 | bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, |
120 | u_int16_t l3num, struct nf_conntrack_tuple *tuple) |
121 | { |
122 | struct nf_conntrack_l3proto *l3proto; |
123 | struct nf_conntrack_l4proto *l4proto; |
124 | unsigned int protoff; |
125 | u_int8_t protonum; |
126 | int ret; |
127 | |
128 | rcu_read_lock(); |
129 | |
130 | l3proto = __nf_ct_l3proto_find(l3num); |
131 | ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); |
132 | if (ret != NF_ACCEPT) { |
133 | rcu_read_unlock(); |
134 | return false; |
135 | } |
136 | |
137 | l4proto = __nf_ct_l4proto_find(l3num, protonum); |
138 | |
139 | ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, |
140 | l3proto, l4proto); |
141 | |
142 | rcu_read_unlock(); |
143 | return ret; |
144 | } |
145 | EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); |
146 | |
147 | bool |
148 | nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, |
149 | const struct nf_conntrack_tuple *orig, |
150 | const struct nf_conntrack_l3proto *l3proto, |
151 | const struct nf_conntrack_l4proto *l4proto) |
152 | { |
153 | memset(inverse, 0, sizeof(*inverse)); |
154 | |
155 | inverse->src.l3num = orig->src.l3num; |
156 | if (l3proto->invert_tuple(inverse, orig) == 0) |
157 | return false; |
158 | |
159 | inverse->dst.dir = !orig->dst.dir; |
160 | |
161 | inverse->dst.protonum = orig->dst.protonum; |
162 | return l4proto->invert_tuple(inverse, orig); |
163 | } |
164 | EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); |
165 | |
166 | static void |
167 | clean_from_lists(struct nf_conn *ct) |
168 | { |
169 | pr_debug("clean_from_lists(%p)\n", ct); |
170 | hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); |
171 | hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); |
172 | |
173 | /* Destroy all pending expectations */ |
174 | nf_ct_remove_expectations(ct); |
175 | } |
176 | |
177 | static void |
178 | destroy_conntrack(struct nf_conntrack *nfct) |
179 | { |
180 | struct nf_conn *ct = (struct nf_conn *)nfct; |
181 | struct net *net = nf_ct_net(ct); |
182 | struct nf_conntrack_l4proto *l4proto; |
183 | |
184 | pr_debug("destroy_conntrack(%p)\n", ct); |
185 | NF_CT_ASSERT(atomic_read(&nfct->use) == 0); |
186 | NF_CT_ASSERT(!timer_pending(&ct->timeout)); |
187 | |
188 | /* To make sure we don't get any weird locking issues here: |
189 | * destroy_conntrack() MUST NOT be called with a write lock |
190 | * to nf_conntrack_lock!!! -HW */ |
191 | rcu_read_lock(); |
192 | l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); |
193 | if (l4proto && l4proto->destroy) |
194 | l4proto->destroy(ct); |
195 | |
196 | rcu_read_unlock(); |
197 | |
198 | spin_lock_bh(&nf_conntrack_lock); |
199 | /* Expectations will have been removed in clean_from_lists, |
200 | * except TFTP can create an expectation on the first packet, |
201 | * before connection is in the list, so we need to clean here, |
202 | * too. */ |
203 | nf_ct_remove_expectations(ct); |
204 | |
205 | /* We overload first tuple to link into unconfirmed list. */ |
206 | if (!nf_ct_is_confirmed(ct)) { |
207 | BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); |
208 | hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); |
209 | } |
210 | |
211 | NF_CT_STAT_INC(net, delete); |
212 | spin_unlock_bh(&nf_conntrack_lock); |
213 | |
214 | if (ct->master) |
215 | nf_ct_put(ct->master); |
216 | |
217 | pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); |
218 | nf_conntrack_free(ct); |
219 | } |
220 | |
221 | void nf_ct_delete_from_lists(struct nf_conn *ct) |
222 | { |
223 | struct net *net = nf_ct_net(ct); |
224 | |
225 | nf_ct_helper_destroy(ct); |
226 | spin_lock_bh(&nf_conntrack_lock); |
227 | /* Inside lock so preempt is disabled on module removal path. |
228 | * Otherwise we can get spurious warnings. */ |
229 | NF_CT_STAT_INC(net, delete_list); |
230 | clean_from_lists(ct); |
231 | spin_unlock_bh(&nf_conntrack_lock); |
232 | } |
233 | EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); |
234 | |
235 | static void death_by_event(unsigned long ul_conntrack) |
236 | { |
237 | struct nf_conn *ct = (void *)ul_conntrack; |
238 | struct net *net = nf_ct_net(ct); |
239 | |
240 | if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { |
241 | /* bad luck, let's retry again */ |
242 | ct->timeout.expires = jiffies + |
243 | (random32() % net->ct.sysctl_events_retry_timeout); |
244 | add_timer(&ct->timeout); |
245 | return; |
246 | } |
247 | /* we've got the event delivered, now it's dying */ |
248 | set_bit(IPS_DYING_BIT, &ct->status); |
249 | spin_lock(&nf_conntrack_lock); |
250 | hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); |
251 | spin_unlock(&nf_conntrack_lock); |
252 | nf_ct_put(ct); |
253 | } |
254 | |
255 | void nf_ct_insert_dying_list(struct nf_conn *ct) |
256 | { |
257 | struct net *net = nf_ct_net(ct); |
258 | |
259 | /* add this conntrack to the dying list */ |
260 | spin_lock_bh(&nf_conntrack_lock); |
261 | hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, |
262 | &net->ct.dying); |
263 | spin_unlock_bh(&nf_conntrack_lock); |
264 | /* set a new timer to retry event delivery */ |
265 | setup_timer(&ct->timeout, death_by_event, (unsigned long)ct); |
266 | ct->timeout.expires = jiffies + |
267 | (random32() % net->ct.sysctl_events_retry_timeout); |
268 | add_timer(&ct->timeout); |
269 | } |
270 | EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list); |
271 | |
272 | static void death_by_timeout(unsigned long ul_conntrack) |
273 | { |
274 | struct nf_conn *ct = (void *)ul_conntrack; |
275 | |
276 | if (!test_bit(IPS_DYING_BIT, &ct->status) && |
277 | unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { |
278 | /* destroy event was not delivered */ |
279 | nf_ct_delete_from_lists(ct); |
280 | nf_ct_insert_dying_list(ct); |
281 | return; |
282 | } |
283 | set_bit(IPS_DYING_BIT, &ct->status); |
284 | nf_ct_delete_from_lists(ct); |
285 | nf_ct_put(ct); |
286 | } |
287 | |
288 | /* |
289 | * Warning : |
290 | * - Caller must take a reference on returned object |
291 | * and recheck nf_ct_tuple_equal(tuple, &h->tuple) |
292 | * OR |
293 | * - Caller must lock nf_conntrack_lock before calling this function |
294 | */ |
295 | struct nf_conntrack_tuple_hash * |
296 | __nf_conntrack_find(struct net *net, u16 zone, |
297 | const struct nf_conntrack_tuple *tuple) |
298 | { |
299 | struct nf_conntrack_tuple_hash *h; |
300 | struct hlist_nulls_node *n; |
301 | unsigned int hash = hash_conntrack(net, zone, tuple); |
302 | |
303 | /* Disable BHs the entire time since we normally need to disable them |
304 | * at least once for the stats anyway. |
305 | */ |
306 | local_bh_disable(); |
307 | begin: |
308 | hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { |
309 | if (nf_ct_tuple_equal(tuple, &h->tuple) && |
310 | nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) { |
311 | NF_CT_STAT_INC(net, found); |
312 | local_bh_enable(); |
313 | return h; |
314 | } |
315 | NF_CT_STAT_INC(net, searched); |
316 | } |
317 | /* |
318 | * if the nulls value we got at the end of this lookup is |
319 | * not the expected one, we must restart lookup. |
320 | * We probably met an item that was moved to another chain. |
321 | */ |
322 | if (get_nulls_value(n) != hash) |
323 | goto begin; |
324 | local_bh_enable(); |
325 | |
326 | return NULL; |
327 | } |
328 | EXPORT_SYMBOL_GPL(__nf_conntrack_find); |
329 | |
330 | /* Find a connection corresponding to a tuple. */ |
331 | struct nf_conntrack_tuple_hash * |
332 | nf_conntrack_find_get(struct net *net, u16 zone, |
333 | const struct nf_conntrack_tuple *tuple) |
334 | { |
335 | struct nf_conntrack_tuple_hash *h; |
336 | struct nf_conn *ct; |
337 | |
338 | rcu_read_lock(); |
339 | begin: |
340 | h = __nf_conntrack_find(net, zone, tuple); |
341 | if (h) { |
342 | ct = nf_ct_tuplehash_to_ctrack(h); |
343 | if (unlikely(nf_ct_is_dying(ct) || |
344 | !atomic_inc_not_zero(&ct->ct_general.use))) |
345 | h = NULL; |
346 | else { |
347 | if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) || |
348 | nf_ct_zone(ct) != zone)) { |
349 | nf_ct_put(ct); |
350 | goto begin; |
351 | } |
352 | } |
353 | } |
354 | rcu_read_unlock(); |
355 | |
356 | return h; |
357 | } |
358 | EXPORT_SYMBOL_GPL(nf_conntrack_find_get); |
359 | |
360 | static void __nf_conntrack_hash_insert(struct nf_conn *ct, |
361 | unsigned int hash, |
362 | unsigned int repl_hash) |
363 | { |
364 | struct net *net = nf_ct_net(ct); |
365 | |
366 | hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, |
367 | &net->ct.hash[hash]); |
368 | hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, |
369 | &net->ct.hash[repl_hash]); |
370 | } |
371 | |
372 | void nf_conntrack_hash_insert(struct nf_conn *ct) |
373 | { |
374 | struct net *net = nf_ct_net(ct); |
375 | unsigned int hash, repl_hash; |
376 | u16 zone; |
377 | |
378 | zone = nf_ct_zone(ct); |
379 | hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); |
380 | repl_hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); |
381 | |
382 | __nf_conntrack_hash_insert(ct, hash, repl_hash); |
383 | } |
384 | EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert); |
385 | |
386 | /* Confirm a connection given skb; places it in hash table */ |
387 | int |
388 | __nf_conntrack_confirm(struct sk_buff *skb) |
389 | { |
390 | unsigned int hash, repl_hash; |
391 | struct nf_conntrack_tuple_hash *h; |
392 | struct nf_conn *ct; |
393 | struct nf_conn_help *help; |
394 | struct hlist_nulls_node *n; |
395 | enum ip_conntrack_info ctinfo; |
396 | struct net *net; |
397 | u16 zone; |
398 | |
399 | ct = nf_ct_get(skb, &ctinfo); |
400 | net = nf_ct_net(ct); |
401 | |
402 | /* ipt_REJECT uses nf_conntrack_attach to attach related |
403 | ICMP/TCP RST packets in other direction. Actual packet |
404 | which created connection will be IP_CT_NEW or for an |
405 | expected connection, IP_CT_RELATED. */ |
406 | if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) |
407 | return NF_ACCEPT; |
408 | |
409 | zone = nf_ct_zone(ct); |
410 | hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); |
411 | repl_hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); |
412 | |
413 | /* We're not in hash table, and we refuse to set up related |
414 | connections for unconfirmed conns. But packet copies and |
415 | REJECT will give spurious warnings here. */ |
416 | /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */ |
417 | |
418 | /* No external references means noone else could have |
419 | confirmed us. */ |
420 | NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); |
421 | pr_debug("Confirming conntrack %p\n", ct); |
422 | |
423 | spin_lock_bh(&nf_conntrack_lock); |
424 | |
425 | /* See if there's one in the list already, including reverse: |
426 | NAT could have grabbed it without realizing, since we're |
427 | not in the hash. If there is, we lost race. */ |
428 | hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) |
429 | if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, |
430 | &h->tuple) && |
431 | zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) |
432 | goto out; |
433 | hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) |
434 | if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, |
435 | &h->tuple) && |
436 | zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) |
437 | goto out; |
438 | |
439 | /* Remove from unconfirmed list */ |
440 | hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); |
441 | |
442 | /* Timer relative to confirmation time, not original |
443 | setting time, otherwise we'd get timer wrap in |
444 | weird delay cases. */ |
445 | ct->timeout.expires += jiffies; |
446 | add_timer(&ct->timeout); |
447 | atomic_inc(&ct->ct_general.use); |
448 | set_bit(IPS_CONFIRMED_BIT, &ct->status); |
449 | |
450 | /* Since the lookup is lockless, hash insertion must be done after |
451 | * starting the timer and setting the CONFIRMED bit. The RCU barriers |
452 | * guarantee that no other CPU can find the conntrack before the above |
453 | * stores are visible. |
454 | */ |
455 | __nf_conntrack_hash_insert(ct, hash, repl_hash); |
456 | NF_CT_STAT_INC(net, insert); |
457 | spin_unlock_bh(&nf_conntrack_lock); |
458 | |
459 | help = nfct_help(ct); |
460 | if (help && help->helper) |
461 | nf_conntrack_event_cache(IPCT_HELPER, ct); |
462 | |
463 | nf_conntrack_event_cache(master_ct(ct) ? |
464 | IPCT_RELATED : IPCT_NEW, ct); |
465 | return NF_ACCEPT; |
466 | |
467 | out: |
468 | NF_CT_STAT_INC(net, insert_failed); |
469 | spin_unlock_bh(&nf_conntrack_lock); |
470 | return NF_DROP; |
471 | } |
472 | EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); |
473 | |
474 | /* Returns true if a connection correspondings to the tuple (required |
475 | for NAT). */ |
476 | int |
477 | nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, |
478 | const struct nf_conn *ignored_conntrack) |
479 | { |
480 | struct net *net = nf_ct_net(ignored_conntrack); |
481 | struct nf_conntrack_tuple_hash *h; |
482 | struct hlist_nulls_node *n; |
483 | struct nf_conn *ct; |
484 | u16 zone = nf_ct_zone(ignored_conntrack); |
485 | unsigned int hash = hash_conntrack(net, zone, tuple); |
486 | |
487 | /* Disable BHs the entire time since we need to disable them at |
488 | * least once for the stats anyway. |
489 | */ |
490 | rcu_read_lock_bh(); |
491 | hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { |
492 | ct = nf_ct_tuplehash_to_ctrack(h); |
493 | if (ct != ignored_conntrack && |
494 | nf_ct_tuple_equal(tuple, &h->tuple) && |
495 | nf_ct_zone(ct) == zone) { |
496 | NF_CT_STAT_INC(net, found); |
497 | rcu_read_unlock_bh(); |
498 | return 1; |
499 | } |
500 | NF_CT_STAT_INC(net, searched); |
501 | } |
502 | rcu_read_unlock_bh(); |
503 | |
504 | return 0; |
505 | } |
506 | EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); |
507 | |
508 | #define NF_CT_EVICTION_RANGE 8 |
509 | |
510 | /* There's a small race here where we may free a just-assured |
511 | connection. Too bad: we're in trouble anyway. */ |
512 | static noinline int early_drop(struct net *net, unsigned int hash) |
513 | { |
514 | /* Use oldest entry, which is roughly LRU */ |
515 | struct nf_conntrack_tuple_hash *h; |
516 | struct nf_conn *ct = NULL, *tmp; |
517 | struct hlist_nulls_node *n; |
518 | unsigned int i, cnt = 0; |
519 | int dropped = 0; |
520 | |
521 | rcu_read_lock(); |
522 | for (i = 0; i < net->ct.htable_size; i++) { |
523 | hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], |
524 | hnnode) { |
525 | tmp = nf_ct_tuplehash_to_ctrack(h); |
526 | if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) |
527 | ct = tmp; |
528 | cnt++; |
529 | } |
530 | |
531 | if (ct != NULL) { |
532 | if (likely(!nf_ct_is_dying(ct) && |
533 | atomic_inc_not_zero(&ct->ct_general.use))) |
534 | break; |
535 | else |
536 | ct = NULL; |
537 | } |
538 | |
539 | if (cnt >= NF_CT_EVICTION_RANGE) |
540 | break; |
541 | |
542 | hash = (hash + 1) % net->ct.htable_size; |
543 | } |
544 | rcu_read_unlock(); |
545 | |
546 | if (!ct) |
547 | return dropped; |
548 | |
549 | if (del_timer(&ct->timeout)) { |
550 | death_by_timeout((unsigned long)ct); |
551 | dropped = 1; |
552 | NF_CT_STAT_INC_ATOMIC(net, early_drop); |
553 | } |
554 | nf_ct_put(ct); |
555 | return dropped; |
556 | } |
557 | |
558 | struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone, |
559 | const struct nf_conntrack_tuple *orig, |
560 | const struct nf_conntrack_tuple *repl, |
561 | gfp_t gfp) |
562 | { |
563 | struct nf_conn *ct; |
564 | |
565 | if (unlikely(!nf_conntrack_hash_rnd_initted)) { |
566 | get_random_bytes(&nf_conntrack_hash_rnd, |
567 | sizeof(nf_conntrack_hash_rnd)); |
568 | nf_conntrack_hash_rnd_initted = 1; |
569 | } |
570 | |
571 | /* We don't want any race condition at early drop stage */ |
572 | atomic_inc(&net->ct.count); |
573 | |
574 | if (nf_conntrack_max && |
575 | unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) { |
576 | unsigned int hash = hash_conntrack(net, zone, orig); |
577 | if (!early_drop(net, hash)) { |
578 | atomic_dec(&net->ct.count); |
579 | if (net_ratelimit()) |
580 | printk(KERN_WARNING |
581 | "nf_conntrack: table full, dropping" |
582 | " packet.\n"); |
583 | return ERR_PTR(-ENOMEM); |
584 | } |
585 | } |
586 | |
587 | /* |
588 | * Do not use kmem_cache_zalloc(), as this cache uses |
589 | * SLAB_DESTROY_BY_RCU. |
590 | */ |
591 | ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp); |
592 | if (ct == NULL) { |
593 | pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n"); |
594 | atomic_dec(&net->ct.count); |
595 | return ERR_PTR(-ENOMEM); |
596 | } |
597 | /* |
598 | * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next |
599 | * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged. |
600 | */ |
601 | memset(&ct->tuplehash[IP_CT_DIR_MAX], 0, |
602 | sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX])); |
603 | spin_lock_init(&ct->lock); |
604 | ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; |
605 | ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; |
606 | ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; |
607 | ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev = NULL; |
608 | /* Don't set timer yet: wait for confirmation */ |
609 | setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct); |
610 | #ifdef CONFIG_NET_NS |
611 | ct->ct_net = net; |
612 | #endif |
613 | #ifdef CONFIG_NF_CONNTRACK_ZONES |
614 | if (zone) { |
615 | struct nf_conntrack_zone *nf_ct_zone; |
616 | |
617 | nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC); |
618 | if (!nf_ct_zone) |
619 | goto out_free; |
620 | nf_ct_zone->id = zone; |
621 | } |
622 | #endif |
623 | /* |
624 | * changes to lookup keys must be done before setting refcnt to 1 |
625 | */ |
626 | smp_wmb(); |
627 | atomic_set(&ct->ct_general.use, 1); |
628 | return ct; |
629 | |
630 | #ifdef CONFIG_NF_CONNTRACK_ZONES |
631 | out_free: |
632 | kmem_cache_free(net->ct.nf_conntrack_cachep, ct); |
633 | return ERR_PTR(-ENOMEM); |
634 | #endif |
635 | } |
636 | EXPORT_SYMBOL_GPL(nf_conntrack_alloc); |
637 | |
638 | void nf_conntrack_free(struct nf_conn *ct) |
639 | { |
640 | struct net *net = nf_ct_net(ct); |
641 | |
642 | nf_ct_ext_destroy(ct); |
643 | atomic_dec(&net->ct.count); |
644 | nf_ct_ext_free(ct); |
645 | kmem_cache_free(net->ct.nf_conntrack_cachep, ct); |
646 | } |
647 | EXPORT_SYMBOL_GPL(nf_conntrack_free); |
648 | |
649 | /* Allocate a new conntrack: we return -ENOMEM if classification |
650 | failed due to stress. Otherwise it really is unclassifiable. */ |
651 | static struct nf_conntrack_tuple_hash * |
652 | init_conntrack(struct net *net, struct nf_conn *tmpl, |
653 | const struct nf_conntrack_tuple *tuple, |
654 | struct nf_conntrack_l3proto *l3proto, |
655 | struct nf_conntrack_l4proto *l4proto, |
656 | struct sk_buff *skb, |
657 | unsigned int dataoff) |
658 | { |
659 | struct nf_conn *ct; |
660 | struct nf_conn_help *help; |
661 | struct nf_conntrack_tuple repl_tuple; |
662 | struct nf_conntrack_ecache *ecache; |
663 | struct nf_conntrack_expect *exp; |
664 | u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; |
665 | |
666 | if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { |
667 | pr_debug("Can't invert tuple.\n"); |
668 | return NULL; |
669 | } |
670 | |
671 | ct = nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC); |
672 | if (IS_ERR(ct)) { |
673 | pr_debug("Can't allocate conntrack.\n"); |
674 | return (struct nf_conntrack_tuple_hash *)ct; |
675 | } |
676 | |
677 | if (!l4proto->new(ct, skb, dataoff)) { |
678 | nf_conntrack_free(ct); |
679 | pr_debug("init conntrack: can't track with proto module\n"); |
680 | return NULL; |
681 | } |
682 | |
683 | nf_ct_acct_ext_add(ct, GFP_ATOMIC); |
684 | |
685 | ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; |
686 | nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, |
687 | ecache ? ecache->expmask : 0, |
688 | GFP_ATOMIC); |
689 | |
690 | spin_lock_bh(&nf_conntrack_lock); |
691 | exp = nf_ct_find_expectation(net, zone, tuple); |
692 | if (exp) { |
693 | pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", |
694 | ct, exp); |
695 | /* Welcome, Mr. Bond. We've been expecting you... */ |
696 | __set_bit(IPS_EXPECTED_BIT, &ct->status); |
697 | ct->master = exp->master; |
698 | if (exp->helper) { |
699 | help = nf_ct_helper_ext_add(ct, GFP_ATOMIC); |
700 | if (help) |
701 | rcu_assign_pointer(help->helper, exp->helper); |
702 | } |
703 | |
704 | #ifdef CONFIG_NF_CONNTRACK_MARK |
705 | ct->mark = exp->master->mark; |
706 | #endif |
707 | #ifdef CONFIG_NF_CONNTRACK_SECMARK |
708 | ct->secmark = exp->master->secmark; |
709 | #endif |
710 | nf_conntrack_get(&ct->master->ct_general); |
711 | NF_CT_STAT_INC(net, expect_new); |
712 | } else { |
713 | __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); |
714 | NF_CT_STAT_INC(net, new); |
715 | } |
716 | |
717 | /* Overload tuple linked list to put us in unconfirmed list. */ |
718 | hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, |
719 | &net->ct.unconfirmed); |
720 | |
721 | spin_unlock_bh(&nf_conntrack_lock); |
722 | |
723 | if (exp) { |
724 | if (exp->expectfn) |
725 | exp->expectfn(ct, exp); |
726 | nf_ct_expect_put(exp); |
727 | } |
728 | |
729 | return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; |
730 | } |
731 | |
732 | /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ |
733 | static inline struct nf_conn * |
734 | resolve_normal_ct(struct net *net, struct nf_conn *tmpl, |
735 | struct sk_buff *skb, |
736 | unsigned int dataoff, |
737 | u_int16_t l3num, |
738 | u_int8_t protonum, |
739 | struct nf_conntrack_l3proto *l3proto, |
740 | struct nf_conntrack_l4proto *l4proto, |
741 | int *set_reply, |
742 | enum ip_conntrack_info *ctinfo) |
743 | { |
744 | struct nf_conntrack_tuple tuple; |
745 | struct nf_conntrack_tuple_hash *h; |
746 | struct nf_conn *ct; |
747 | u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; |
748 | |
749 | if (!nf_ct_get_tuple(skb, skb_network_offset(skb), |
750 | dataoff, l3num, protonum, &tuple, l3proto, |
751 | l4proto)) { |
752 | pr_debug("resolve_normal_ct: Can't get tuple\n"); |
753 | return NULL; |
754 | } |
755 | |
756 | /* look for tuple match */ |
757 | h = nf_conntrack_find_get(net, zone, &tuple); |
758 | if (!h) { |
759 | h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, |
760 | skb, dataoff); |
761 | if (!h) |
762 | return NULL; |
763 | if (IS_ERR(h)) |
764 | return (void *)h; |
765 | } |
766 | ct = nf_ct_tuplehash_to_ctrack(h); |
767 | |
768 | /* It exists; we have (non-exclusive) reference. */ |
769 | if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { |
770 | *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY; |
771 | /* Please set reply bit if this packet OK */ |
772 | *set_reply = 1; |
773 | } else { |
774 | /* Once we've had two way comms, always ESTABLISHED. */ |
775 | if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { |
776 | pr_debug("nf_conntrack_in: normal packet for %p\n", ct); |
777 | *ctinfo = IP_CT_ESTABLISHED; |
778 | } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { |
779 | pr_debug("nf_conntrack_in: related packet for %p\n", |
780 | ct); |
781 | *ctinfo = IP_CT_RELATED; |
782 | } else { |
783 | pr_debug("nf_conntrack_in: new packet for %p\n", ct); |
784 | *ctinfo = IP_CT_NEW; |
785 | } |
786 | *set_reply = 0; |
787 | } |
788 | skb->nfct = &ct->ct_general; |
789 | skb->nfctinfo = *ctinfo; |
790 | return ct; |
791 | } |
792 | |
793 | unsigned int |
794 | nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, |
795 | struct sk_buff *skb) |
796 | { |
797 | struct nf_conn *ct, *tmpl = NULL; |
798 | enum ip_conntrack_info ctinfo; |
799 | struct nf_conntrack_l3proto *l3proto; |
800 | struct nf_conntrack_l4proto *l4proto; |
801 | unsigned int dataoff; |
802 | u_int8_t protonum; |
803 | int set_reply = 0; |
804 | int ret; |
805 | |
806 | if (skb->nfct) { |
807 | /* Previously seen (loopback or untracked)? Ignore. */ |
808 | tmpl = (struct nf_conn *)skb->nfct; |
809 | if (!nf_ct_is_template(tmpl)) { |
810 | NF_CT_STAT_INC_ATOMIC(net, ignore); |
811 | return NF_ACCEPT; |
812 | } |
813 | skb->nfct = NULL; |
814 | } |
815 | |
816 | /* rcu_read_lock()ed by nf_hook_slow */ |
817 | l3proto = __nf_ct_l3proto_find(pf); |
818 | ret = l3proto->get_l4proto(skb, skb_network_offset(skb), |
819 | &dataoff, &protonum); |
820 | if (ret <= 0) { |
821 | pr_debug("not prepared to track yet or error occured\n"); |
822 | NF_CT_STAT_INC_ATOMIC(net, error); |
823 | NF_CT_STAT_INC_ATOMIC(net, invalid); |
824 | ret = -ret; |
825 | goto out; |
826 | } |
827 | |
828 | l4proto = __nf_ct_l4proto_find(pf, protonum); |
829 | |
830 | /* It may be an special packet, error, unclean... |
831 | * inverse of the return code tells to the netfilter |
832 | * core what to do with the packet. */ |
833 | if (l4proto->error != NULL) { |
834 | ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo, |
835 | pf, hooknum); |
836 | if (ret <= 0) { |
837 | NF_CT_STAT_INC_ATOMIC(net, error); |
838 | NF_CT_STAT_INC_ATOMIC(net, invalid); |
839 | ret = -ret; |
840 | goto out; |
841 | } |
842 | } |
843 | |
844 | ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, |
845 | l3proto, l4proto, &set_reply, &ctinfo); |
846 | if (!ct) { |
847 | /* Not valid part of a connection */ |
848 | NF_CT_STAT_INC_ATOMIC(net, invalid); |
849 | ret = NF_ACCEPT; |
850 | goto out; |
851 | } |
852 | |
853 | if (IS_ERR(ct)) { |
854 | /* Too stressed to deal. */ |
855 | NF_CT_STAT_INC_ATOMIC(net, drop); |
856 | ret = NF_DROP; |
857 | goto out; |
858 | } |
859 | |
860 | NF_CT_ASSERT(skb->nfct); |
861 | |
862 | ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum); |
863 | if (ret <= 0) { |
864 | /* Invalid: inverse of the return code tells |
865 | * the netfilter core what to do */ |
866 | pr_debug("nf_conntrack_in: Can't track with proto module\n"); |
867 | nf_conntrack_put(skb->nfct); |
868 | skb->nfct = NULL; |
869 | NF_CT_STAT_INC_ATOMIC(net, invalid); |
870 | if (ret == -NF_DROP) |
871 | NF_CT_STAT_INC_ATOMIC(net, drop); |
872 | ret = -ret; |
873 | goto out; |
874 | } |
875 | |
876 | if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) |
877 | nf_conntrack_event_cache(IPCT_REPLY, ct); |
878 | out: |
879 | if (tmpl) |
880 | nf_ct_put(tmpl); |
881 | |
882 | return ret; |
883 | } |
884 | EXPORT_SYMBOL_GPL(nf_conntrack_in); |
885 | |
886 | bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, |
887 | const struct nf_conntrack_tuple *orig) |
888 | { |
889 | bool ret; |
890 | |
891 | rcu_read_lock(); |
892 | ret = nf_ct_invert_tuple(inverse, orig, |
893 | __nf_ct_l3proto_find(orig->src.l3num), |
894 | __nf_ct_l4proto_find(orig->src.l3num, |
895 | orig->dst.protonum)); |
896 | rcu_read_unlock(); |
897 | return ret; |
898 | } |
899 | EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); |
900 | |
901 | /* Alter reply tuple (maybe alter helper). This is for NAT, and is |
902 | implicitly racy: see __nf_conntrack_confirm */ |
903 | void nf_conntrack_alter_reply(struct nf_conn *ct, |
904 | const struct nf_conntrack_tuple *newreply) |
905 | { |
906 | struct nf_conn_help *help = nfct_help(ct); |
907 | |
908 | /* Should be unconfirmed, so not in hash table yet */ |
909 | NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); |
910 | |
911 | pr_debug("Altering reply tuple of %p to ", ct); |
912 | nf_ct_dump_tuple(newreply); |
913 | |
914 | ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; |
915 | if (ct->master || (help && !hlist_empty(&help->expectations))) |
916 | return; |
917 | |
918 | rcu_read_lock(); |
919 | __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); |
920 | rcu_read_unlock(); |
921 | } |
922 | EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); |
923 | |
924 | /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ |
925 | void __nf_ct_refresh_acct(struct nf_conn *ct, |
926 | enum ip_conntrack_info ctinfo, |
927 | const struct sk_buff *skb, |
928 | unsigned long extra_jiffies, |
929 | int do_acct) |
930 | { |
931 | NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); |
932 | NF_CT_ASSERT(skb); |
933 | |
934 | /* Only update if this is not a fixed timeout */ |
935 | if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) |
936 | goto acct; |
937 | |
938 | /* If not in hash table, timer will not be active yet */ |
939 | if (!nf_ct_is_confirmed(ct)) { |
940 | ct->timeout.expires = extra_jiffies; |
941 | } else { |
942 | unsigned long newtime = jiffies + extra_jiffies; |
943 | |
944 | /* Only update the timeout if the new timeout is at least |
945 | HZ jiffies from the old timeout. Need del_timer for race |
946 | avoidance (may already be dying). */ |
947 | if (newtime - ct->timeout.expires >= HZ) |
948 | mod_timer_pending(&ct->timeout, newtime); |
949 | } |
950 | |
951 | acct: |
952 | if (do_acct) { |
953 | struct nf_conn_counter *acct; |
954 | |
955 | acct = nf_conn_acct_find(ct); |
956 | if (acct) { |
957 | spin_lock_bh(&ct->lock); |
958 | acct[CTINFO2DIR(ctinfo)].packets++; |
959 | acct[CTINFO2DIR(ctinfo)].bytes += |
960 | skb->len - skb_network_offset(skb); |
961 | spin_unlock_bh(&ct->lock); |
962 | } |
963 | } |
964 | } |
965 | EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); |
966 | |
967 | bool __nf_ct_kill_acct(struct nf_conn *ct, |
968 | enum ip_conntrack_info ctinfo, |
969 | const struct sk_buff *skb, |
970 | int do_acct) |
971 | { |
972 | if (do_acct) { |
973 | struct nf_conn_counter *acct; |
974 | |
975 | acct = nf_conn_acct_find(ct); |
976 | if (acct) { |
977 | spin_lock_bh(&ct->lock); |
978 | acct[CTINFO2DIR(ctinfo)].packets++; |
979 | acct[CTINFO2DIR(ctinfo)].bytes += |
980 | skb->len - skb_network_offset(skb); |
981 | spin_unlock_bh(&ct->lock); |
982 | } |
983 | } |
984 | |
985 | if (del_timer(&ct->timeout)) { |
986 | ct->timeout.function((unsigned long)ct); |
987 | return true; |
988 | } |
989 | return false; |
990 | } |
991 | EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); |
992 | |
993 | #ifdef CONFIG_NF_CONNTRACK_ZONES |
994 | static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = { |
995 | .len = sizeof(struct nf_conntrack_zone), |
996 | .align = __alignof__(struct nf_conntrack_zone), |
997 | .id = NF_CT_EXT_ZONE, |
998 | }; |
999 | #endif |
1000 | |
1001 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
1002 | |
1003 | #include <linux/netfilter/nfnetlink.h> |
1004 | #include <linux/netfilter/nfnetlink_conntrack.h> |
1005 | #include <linux/mutex.h> |
1006 | |
1007 | /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be |
1008 | * in ip_conntrack_core, since we don't want the protocols to autoload |
1009 | * or depend on ctnetlink */ |
1010 | int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, |
1011 | const struct nf_conntrack_tuple *tuple) |
1012 | { |
1013 | NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port); |
1014 | NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port); |
1015 | return 0; |
1016 | |
1017 | nla_put_failure: |
1018 | return -1; |
1019 | } |
1020 | EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); |
1021 | |
1022 | const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { |
1023 | [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, |
1024 | [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, |
1025 | }; |
1026 | EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); |
1027 | |
1028 | int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], |
1029 | struct nf_conntrack_tuple *t) |
1030 | { |
1031 | if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) |
1032 | return -EINVAL; |
1033 | |
1034 | t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); |
1035 | t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); |
1036 | |
1037 | return 0; |
1038 | } |
1039 | EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); |
1040 | |
1041 | int nf_ct_port_nlattr_tuple_size(void) |
1042 | { |
1043 | return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); |
1044 | } |
1045 | EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); |
1046 | #endif |
1047 | |
1048 | /* Used by ipt_REJECT and ip6t_REJECT. */ |
1049 | static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) |
1050 | { |
1051 | struct nf_conn *ct; |
1052 | enum ip_conntrack_info ctinfo; |
1053 | |
1054 | /* This ICMP is in reverse direction to the packet which caused it */ |
1055 | ct = nf_ct_get(skb, &ctinfo); |
1056 | if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) |
1057 | ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY; |
1058 | else |
1059 | ctinfo = IP_CT_RELATED; |
1060 | |
1061 | /* Attach to new skbuff, and increment count */ |
1062 | nskb->nfct = &ct->ct_general; |
1063 | nskb->nfctinfo = ctinfo; |
1064 | nf_conntrack_get(nskb->nfct); |
1065 | } |
1066 | |
1067 | /* Bring out ya dead! */ |
1068 | static struct nf_conn * |
1069 | get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), |
1070 | void *data, unsigned int *bucket) |
1071 | { |
1072 | struct nf_conntrack_tuple_hash *h; |
1073 | struct nf_conn *ct; |
1074 | struct hlist_nulls_node *n; |
1075 | |
1076 | spin_lock_bh(&nf_conntrack_lock); |
1077 | for (; *bucket < net->ct.htable_size; (*bucket)++) { |
1078 | hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { |
1079 | ct = nf_ct_tuplehash_to_ctrack(h); |
1080 | if (iter(ct, data)) |
1081 | goto found; |
1082 | } |
1083 | } |
1084 | hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) { |
1085 | ct = nf_ct_tuplehash_to_ctrack(h); |
1086 | if (iter(ct, data)) |
1087 | set_bit(IPS_DYING_BIT, &ct->status); |
1088 | } |
1089 | spin_unlock_bh(&nf_conntrack_lock); |
1090 | return NULL; |
1091 | found: |
1092 | atomic_inc(&ct->ct_general.use); |
1093 | spin_unlock_bh(&nf_conntrack_lock); |
1094 | return ct; |
1095 | } |
1096 | |
1097 | void nf_ct_iterate_cleanup(struct net *net, |
1098 | int (*iter)(struct nf_conn *i, void *data), |
1099 | void *data) |
1100 | { |
1101 | struct nf_conn *ct; |
1102 | unsigned int bucket = 0; |
1103 | |
1104 | while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { |
1105 | /* Time to push up daises... */ |
1106 | if (del_timer(&ct->timeout)) |
1107 | death_by_timeout((unsigned long)ct); |
1108 | /* ... else the timer will get him soon. */ |
1109 | |
1110 | nf_ct_put(ct); |
1111 | } |
1112 | } |
1113 | EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); |
1114 | |
1115 | struct __nf_ct_flush_report { |
1116 | u32 pid; |
1117 | int report; |
1118 | }; |
1119 | |
1120 | static int kill_report(struct nf_conn *i, void *data) |
1121 | { |
1122 | struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data; |
1123 | |
1124 | /* If we fail to deliver the event, death_by_timeout() will retry */ |
1125 | if (nf_conntrack_event_report(IPCT_DESTROY, i, |
1126 | fr->pid, fr->report) < 0) |
1127 | return 1; |
1128 | |
1129 | /* Avoid the delivery of the destroy event in death_by_timeout(). */ |
1130 | set_bit(IPS_DYING_BIT, &i->status); |
1131 | return 1; |
1132 | } |
1133 | |
1134 | static int kill_all(struct nf_conn *i, void *data) |
1135 | { |
1136 | return 1; |
1137 | } |
1138 | |
1139 | void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size) |
1140 | { |
1141 | if (vmalloced) |
1142 | vfree(hash); |
1143 | else |
1144 | free_pages((unsigned long)hash, |
1145 | get_order(sizeof(struct hlist_head) * size)); |
1146 | } |
1147 | EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); |
1148 | |
1149 | void nf_conntrack_flush_report(struct net *net, u32 pid, int report) |
1150 | { |
1151 | struct __nf_ct_flush_report fr = { |
1152 | .pid = pid, |
1153 | .report = report, |
1154 | }; |
1155 | nf_ct_iterate_cleanup(net, kill_report, &fr); |
1156 | } |
1157 | EXPORT_SYMBOL_GPL(nf_conntrack_flush_report); |
1158 | |
1159 | static void nf_ct_release_dying_list(struct net *net) |
1160 | { |
1161 | struct nf_conntrack_tuple_hash *h; |
1162 | struct nf_conn *ct; |
1163 | struct hlist_nulls_node *n; |
1164 | |
1165 | spin_lock_bh(&nf_conntrack_lock); |
1166 | hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) { |
1167 | ct = nf_ct_tuplehash_to_ctrack(h); |
1168 | /* never fails to remove them, no listeners at this point */ |
1169 | nf_ct_kill(ct); |
1170 | } |
1171 | spin_unlock_bh(&nf_conntrack_lock); |
1172 | } |
1173 | |
1174 | static void nf_conntrack_cleanup_init_net(void) |
1175 | { |
1176 | /* wait until all references to nf_conntrack_untracked are dropped */ |
1177 | while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1) |
1178 | schedule(); |
1179 | |
1180 | nf_conntrack_helper_fini(); |
1181 | nf_conntrack_proto_fini(); |
1182 | #ifdef CONFIG_NF_CONNTRACK_ZONES |
1183 | nf_ct_extend_unregister(&nf_ct_zone_extend); |
1184 | #endif |
1185 | } |
1186 | |
1187 | static void nf_conntrack_cleanup_net(struct net *net) |
1188 | { |
1189 | i_see_dead_people: |
1190 | nf_ct_iterate_cleanup(net, kill_all, NULL); |
1191 | nf_ct_release_dying_list(net); |
1192 | if (atomic_read(&net->ct.count) != 0) { |
1193 | schedule(); |
1194 | goto i_see_dead_people; |
1195 | } |
1196 | |
1197 | nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, |
1198 | net->ct.htable_size); |
1199 | nf_conntrack_ecache_fini(net); |
1200 | nf_conntrack_acct_fini(net); |
1201 | nf_conntrack_expect_fini(net); |
1202 | kmem_cache_destroy(net->ct.nf_conntrack_cachep); |
1203 | kfree(net->ct.slabname); |
1204 | free_percpu(net->ct.stat); |
1205 | } |
1206 | |
1207 | /* Mishearing the voices in his head, our hero wonders how he's |
1208 | supposed to kill the mall. */ |
1209 | void nf_conntrack_cleanup(struct net *net) |
1210 | { |
1211 | if (net_eq(net, &init_net)) |
1212 | rcu_assign_pointer(ip_ct_attach, NULL); |
1213 | |
1214 | /* This makes sure all current packets have passed through |
1215 | netfilter framework. Roll on, two-stage module |
1216 | delete... */ |
1217 | synchronize_net(); |
1218 | |
1219 | nf_conntrack_cleanup_net(net); |
1220 | |
1221 | if (net_eq(net, &init_net)) { |
1222 | rcu_assign_pointer(nf_ct_destroy, NULL); |
1223 | nf_conntrack_cleanup_init_net(); |
1224 | } |
1225 | } |
1226 | |
1227 | void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls) |
1228 | { |
1229 | struct hlist_nulls_head *hash; |
1230 | unsigned int nr_slots, i; |
1231 | size_t sz; |
1232 | |
1233 | *vmalloced = 0; |
1234 | |
1235 | BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); |
1236 | nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); |
1237 | sz = nr_slots * sizeof(struct hlist_nulls_head); |
1238 | hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, |
1239 | get_order(sz)); |
1240 | if (!hash) { |
1241 | *vmalloced = 1; |
1242 | printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); |
1243 | hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL); |
1244 | } |
1245 | |
1246 | if (hash && nulls) |
1247 | for (i = 0; i < nr_slots; i++) |
1248 | INIT_HLIST_NULLS_HEAD(&hash[i], i); |
1249 | |
1250 | return hash; |
1251 | } |
1252 | EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); |
1253 | |
1254 | int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) |
1255 | { |
1256 | int i, bucket, vmalloced, old_vmalloced; |
1257 | unsigned int hashsize, old_size; |
1258 | struct hlist_nulls_head *hash, *old_hash; |
1259 | struct nf_conntrack_tuple_hash *h; |
1260 | struct nf_conn *ct; |
1261 | |
1262 | if (current->nsproxy->net_ns != &init_net) |
1263 | return -EOPNOTSUPP; |
1264 | |
1265 | /* On boot, we can set this without any fancy locking. */ |
1266 | if (!nf_conntrack_htable_size) |
1267 | return param_set_uint(val, kp); |
1268 | |
1269 | hashsize = simple_strtoul(val, NULL, 0); |
1270 | if (!hashsize) |
1271 | return -EINVAL; |
1272 | |
1273 | hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1); |
1274 | if (!hash) |
1275 | return -ENOMEM; |
1276 | |
1277 | /* Lookups in the old hash might happen in parallel, which means we |
1278 | * might get false negatives during connection lookup. New connections |
1279 | * created because of a false negative won't make it into the hash |
1280 | * though since that required taking the lock. |
1281 | */ |
1282 | spin_lock_bh(&nf_conntrack_lock); |
1283 | for (i = 0; i < init_net.ct.htable_size; i++) { |
1284 | while (!hlist_nulls_empty(&init_net.ct.hash[i])) { |
1285 | h = hlist_nulls_entry(init_net.ct.hash[i].first, |
1286 | struct nf_conntrack_tuple_hash, hnnode); |
1287 | ct = nf_ct_tuplehash_to_ctrack(h); |
1288 | hlist_nulls_del_rcu(&h->hnnode); |
1289 | bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct), |
1290 | hashsize, |
1291 | nf_conntrack_hash_rnd); |
1292 | hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); |
1293 | } |
1294 | } |
1295 | old_size = init_net.ct.htable_size; |
1296 | old_vmalloced = init_net.ct.hash_vmalloc; |
1297 | old_hash = init_net.ct.hash; |
1298 | |
1299 | init_net.ct.htable_size = nf_conntrack_htable_size = hashsize; |
1300 | init_net.ct.hash_vmalloc = vmalloced; |
1301 | init_net.ct.hash = hash; |
1302 | spin_unlock_bh(&nf_conntrack_lock); |
1303 | |
1304 | nf_ct_free_hashtable(old_hash, old_vmalloced, old_size); |
1305 | return 0; |
1306 | } |
1307 | EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); |
1308 | |
1309 | module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, |
1310 | &nf_conntrack_htable_size, 0600); |
1311 | |
1312 | static int nf_conntrack_init_init_net(void) |
1313 | { |
1314 | int max_factor = 8; |
1315 | int ret; |
1316 | |
1317 | /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB |
1318 | * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ |
1319 | if (!nf_conntrack_htable_size) { |
1320 | nf_conntrack_htable_size |
1321 | = (((totalram_pages << PAGE_SHIFT) / 16384) |
1322 | / sizeof(struct hlist_head)); |
1323 | if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) |
1324 | nf_conntrack_htable_size = 16384; |
1325 | if (nf_conntrack_htable_size < 32) |
1326 | nf_conntrack_htable_size = 32; |
1327 | |
1328 | /* Use a max. factor of four by default to get the same max as |
1329 | * with the old struct list_heads. When a table size is given |
1330 | * we use the old value of 8 to avoid reducing the max. |
1331 | * entries. */ |
1332 | max_factor = 4; |
1333 | } |
1334 | nf_conntrack_max = max_factor * nf_conntrack_htable_size; |
1335 | |
1336 | printk("nf_conntrack version %s (%u buckets, %d max)\n", |
1337 | NF_CONNTRACK_VERSION, nf_conntrack_htable_size, |
1338 | nf_conntrack_max); |
1339 | |
1340 | ret = nf_conntrack_proto_init(); |
1341 | if (ret < 0) |
1342 | goto err_proto; |
1343 | |
1344 | ret = nf_conntrack_helper_init(); |
1345 | if (ret < 0) |
1346 | goto err_helper; |
1347 | |
1348 | #ifdef CONFIG_NF_CONNTRACK_ZONES |
1349 | ret = nf_ct_extend_register(&nf_ct_zone_extend); |
1350 | if (ret < 0) |
1351 | goto err_extend; |
1352 | #endif |
1353 | /* Set up fake conntrack: to never be deleted, not in any hashes */ |
1354 | #ifdef CONFIG_NET_NS |
1355 | nf_conntrack_untracked.ct_net = &init_net; |
1356 | #endif |
1357 | atomic_set(&nf_conntrack_untracked.ct_general.use, 1); |
1358 | /* - and look it like as a confirmed connection */ |
1359 | set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status); |
1360 | |
1361 | return 0; |
1362 | |
1363 | #ifdef CONFIG_NF_CONNTRACK_ZONES |
1364 | err_extend: |
1365 | nf_conntrack_helper_fini(); |
1366 | #endif |
1367 | err_helper: |
1368 | nf_conntrack_proto_fini(); |
1369 | err_proto: |
1370 | return ret; |
1371 | } |
1372 | |
1373 | /* |
1374 | * We need to use special "null" values, not used in hash table |
1375 | */ |
1376 | #define UNCONFIRMED_NULLS_VAL ((1<<30)+0) |
1377 | #define DYING_NULLS_VAL ((1<<30)+1) |
1378 | |
1379 | static int nf_conntrack_init_net(struct net *net) |
1380 | { |
1381 | int ret; |
1382 | |
1383 | atomic_set(&net->ct.count, 0); |
1384 | INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); |
1385 | INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); |
1386 | net->ct.stat = alloc_percpu(struct ip_conntrack_stat); |
1387 | if (!net->ct.stat) { |
1388 | ret = -ENOMEM; |
1389 | goto err_stat; |
1390 | } |
1391 | |
1392 | net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); |
1393 | if (!net->ct.slabname) { |
1394 | ret = -ENOMEM; |
1395 | goto err_slabname; |
1396 | } |
1397 | |
1398 | net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname, |
1399 | sizeof(struct nf_conn), 0, |
1400 | SLAB_DESTROY_BY_RCU, NULL); |
1401 | if (!net->ct.nf_conntrack_cachep) { |
1402 | printk(KERN_ERR "Unable to create nf_conn slab cache\n"); |
1403 | ret = -ENOMEM; |
1404 | goto err_cache; |
1405 | } |
1406 | |
1407 | net->ct.htable_size = nf_conntrack_htable_size; |
1408 | net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, |
1409 | &net->ct.hash_vmalloc, 1); |
1410 | if (!net->ct.hash) { |
1411 | ret = -ENOMEM; |
1412 | printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); |
1413 | goto err_hash; |
1414 | } |
1415 | ret = nf_conntrack_expect_init(net); |
1416 | if (ret < 0) |
1417 | goto err_expect; |
1418 | ret = nf_conntrack_acct_init(net); |
1419 | if (ret < 0) |
1420 | goto err_acct; |
1421 | ret = nf_conntrack_ecache_init(net); |
1422 | if (ret < 0) |
1423 | goto err_ecache; |
1424 | |
1425 | return 0; |
1426 | |
1427 | err_ecache: |
1428 | nf_conntrack_acct_fini(net); |
1429 | err_acct: |
1430 | nf_conntrack_expect_fini(net); |
1431 | err_expect: |
1432 | nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, |
1433 | net->ct.htable_size); |
1434 | err_hash: |
1435 | kmem_cache_destroy(net->ct.nf_conntrack_cachep); |
1436 | err_cache: |
1437 | kfree(net->ct.slabname); |
1438 | err_slabname: |
1439 | free_percpu(net->ct.stat); |
1440 | err_stat: |
1441 | return ret; |
1442 | } |
1443 | |
1444 | s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, |
1445 | enum ip_conntrack_dir dir, |
1446 | u32 seq); |
1447 | EXPORT_SYMBOL_GPL(nf_ct_nat_offset); |
1448 | |
1449 | int nf_conntrack_init(struct net *net) |
1450 | { |
1451 | int ret; |
1452 | |
1453 | if (net_eq(net, &init_net)) { |
1454 | ret = nf_conntrack_init_init_net(); |
1455 | if (ret < 0) |
1456 | goto out_init_net; |
1457 | } |
1458 | ret = nf_conntrack_init_net(net); |
1459 | if (ret < 0) |
1460 | goto out_net; |
1461 | |
1462 | if (net_eq(net, &init_net)) { |
1463 | /* For use by REJECT target */ |
1464 | rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach); |
1465 | rcu_assign_pointer(nf_ct_destroy, destroy_conntrack); |
1466 | |
1467 | /* Howto get NAT offsets */ |
1468 | rcu_assign_pointer(nf_ct_nat_offset, NULL); |
1469 | } |
1470 | return 0; |
1471 | |
1472 | out_net: |
1473 | if (net_eq(net, &init_net)) |
1474 | nf_conntrack_cleanup_init_net(); |
1475 | out_init_net: |
1476 | return ret; |
1477 | } |
1478 |
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