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Commit | Line | Data |
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601e68e1 | 1 | /* netfilter.c: look after the filters for various protocols. |
f6ebe77f HW |
2 | * Heavily influenced by the old firewall.c by David Bonn and Alan Cox. |
3 | * | |
4 | * Thanks to Rob `CmdrTaco' Malda for not influencing this code in any | |
5 | * way. | |
6 | * | |
7 | * Rusty Russell (C)2000 -- This code is GPL. | |
f229f6ce | 8 | * Patrick McHardy (c) 2006-2012 |
f6ebe77f | 9 | */ |
f6ebe77f HW |
10 | #include <linux/kernel.h> |
11 | #include <linux/netfilter.h> | |
12 | #include <net/protocol.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/skbuff.h> | |
15 | #include <linux/wait.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/if.h> | |
19 | #include <linux/netdevice.h> | |
56768644 | 20 | #include <linux/netfilter_ipv6.h> |
f6ebe77f HW |
21 | #include <linux/inetdevice.h> |
22 | #include <linux/proc_fs.h> | |
d486dd1f | 23 | #include <linux/mutex.h> |
5a0e3ad6 | 24 | #include <linux/slab.h> |
e3b37f11 | 25 | #include <linux/rcupdate.h> |
457c4cbc | 26 | #include <net/net_namespace.h> |
f6ebe77f HW |
27 | #include <net/sock.h> |
28 | ||
29 | #include "nf_internals.h" | |
30 | ||
d486dd1f | 31 | static DEFINE_MUTEX(afinfo_mutex); |
bce8032e | 32 | |
0906a372 | 33 | const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO] __read_mostly; |
bce8032e | 34 | EXPORT_SYMBOL(nf_afinfo); |
2a7851bf FW |
35 | const struct nf_ipv6_ops __rcu *nf_ipv6_ops __read_mostly; |
36 | EXPORT_SYMBOL_GPL(nf_ipv6_ops); | |
bce8032e | 37 | |
e7c8899f FW |
38 | DEFINE_PER_CPU(bool, nf_skb_duplicated); |
39 | EXPORT_SYMBOL_GPL(nf_skb_duplicated); | |
40 | ||
1e796fda | 41 | int nf_register_afinfo(const struct nf_afinfo *afinfo) |
bce8032e | 42 | { |
7926dbfa | 43 | mutex_lock(&afinfo_mutex); |
a9b3cd7f | 44 | RCU_INIT_POINTER(nf_afinfo[afinfo->family], afinfo); |
d486dd1f | 45 | mutex_unlock(&afinfo_mutex); |
bce8032e PM |
46 | return 0; |
47 | } | |
48 | EXPORT_SYMBOL_GPL(nf_register_afinfo); | |
49 | ||
1e796fda | 50 | void nf_unregister_afinfo(const struct nf_afinfo *afinfo) |
bce8032e | 51 | { |
d486dd1f | 52 | mutex_lock(&afinfo_mutex); |
a9b3cd7f | 53 | RCU_INIT_POINTER(nf_afinfo[afinfo->family], NULL); |
d486dd1f | 54 | mutex_unlock(&afinfo_mutex); |
bce8032e PM |
55 | synchronize_rcu(); |
56 | } | |
57 | EXPORT_SYMBOL_GPL(nf_unregister_afinfo); | |
58 | ||
d1c85c2e | 59 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 60 | struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; |
a2d7ec58 ED |
61 | EXPORT_SYMBOL(nf_hooks_needed); |
62 | #endif | |
63 | ||
fd706d69 | 64 | static DEFINE_MUTEX(nf_hook_mutex); |
e3b37f11 AC |
65 | #define nf_entry_dereference(e) \ |
66 | rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex)) | |
f6ebe77f | 67 | |
bd3769bf | 68 | static struct nf_hook_entry __rcu **nf_hook_entry_head(struct net *net, const struct nf_hook_ops *reg) |
f6ebe77f | 69 | { |
0edcf282 | 70 | if (reg->pf != NFPROTO_NETDEV) |
bd3769bf LT |
71 | return net->nf.hooks[reg->pf]+reg->hooknum; |
72 | ||
e687ad60 | 73 | #ifdef CONFIG_NETFILTER_INGRESS |
bd3769bf | 74 | if (reg->hooknum == NF_NETDEV_INGRESS) { |
085db2c0 | 75 | if (reg->dev && dev_net(reg->dev) == net) |
bd3769bf | 76 | return ®->dev->nf_hooks_ingress; |
e687ad60 | 77 | } |
7816ec56 | 78 | #endif |
bd3769bf | 79 | return NULL; |
e3b37f11 | 80 | } |
7181ebaf | 81 | |
085db2c0 | 82 | int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) |
0edcf282 | 83 | { |
bd3769bf LT |
84 | struct nf_hook_entry __rcu **pp; |
85 | struct nf_hook_entry *entry, *p; | |
085db2c0 | 86 | |
7816ec56 AC |
87 | if (reg->pf == NFPROTO_NETDEV) { |
88 | #ifndef CONFIG_NETFILTER_INGRESS | |
89 | if (reg->hooknum == NF_NETDEV_INGRESS) | |
90 | return -EOPNOTSUPP; | |
91 | #endif | |
92 | if (reg->hooknum != NF_NETDEV_INGRESS || | |
93 | !reg->dev || dev_net(reg->dev) != net) | |
94 | return -EINVAL; | |
95 | } | |
d4bb5caa | 96 | |
bd3769bf LT |
97 | pp = nf_hook_entry_head(net, reg); |
98 | if (!pp) | |
99 | return -EINVAL; | |
100 | ||
7181ebaf PNA |
101 | entry = kmalloc(sizeof(*entry), GFP_KERNEL); |
102 | if (!entry) | |
085db2c0 | 103 | return -ENOMEM; |
0edcf282 | 104 | |
7181ebaf PNA |
105 | entry->orig_ops = reg; |
106 | entry->ops = *reg; | |
e3b37f11 AC |
107 | entry->next = NULL; |
108 | ||
109 | mutex_lock(&nf_hook_mutex); | |
085db2c0 | 110 | |
bd3769bf LT |
111 | /* Find the spot in the list */ |
112 | while ((p = nf_entry_dereference(*pp)) != NULL) { | |
113 | if (reg->priority < p->orig_ops->priority) | |
114 | break; | |
115 | pp = &p->next; | |
f6ebe77f | 116 | } |
bd3769bf LT |
117 | rcu_assign_pointer(entry->next, p); |
118 | rcu_assign_pointer(*pp, entry); | |
e3b37f11 | 119 | |
fd706d69 | 120 | mutex_unlock(&nf_hook_mutex); |
4c091156 EB |
121 | #ifdef CONFIG_NETFILTER_INGRESS |
122 | if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) | |
123 | net_inc_ingress_queue(); | |
124 | #endif | |
d1c85c2e | 125 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 126 | static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]); |
a2d7ec58 | 127 | #endif |
f6ebe77f HW |
128 | return 0; |
129 | } | |
085db2c0 | 130 | EXPORT_SYMBOL(nf_register_net_hook); |
f6ebe77f | 131 | |
085db2c0 | 132 | void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg) |
f6ebe77f | 133 | { |
bd3769bf LT |
134 | struct nf_hook_entry __rcu **pp; |
135 | struct nf_hook_entry *p; | |
136 | ||
137 | pp = nf_hook_entry_head(net, reg); | |
138 | if (WARN_ON_ONCE(!pp)) | |
139 | return; | |
085db2c0 | 140 | |
fd706d69 | 141 | mutex_lock(&nf_hook_mutex); |
bd3769bf LT |
142 | while ((p = nf_entry_dereference(*pp)) != NULL) { |
143 | if (p->orig_ops == reg) { | |
144 | rcu_assign_pointer(*pp, p->next); | |
145 | break; | |
085db2c0 | 146 | } |
bd3769bf | 147 | pp = &p->next; |
085db2c0 | 148 | } |
fd706d69 | 149 | mutex_unlock(&nf_hook_mutex); |
bd3769bf | 150 | if (!p) { |
085db2c0 EB |
151 | WARN(1, "nf_unregister_net_hook: hook not found!\n"); |
152 | return; | |
153 | } | |
e687ad60 | 154 | #ifdef CONFIG_NETFILTER_INGRESS |
4c091156 EB |
155 | if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) |
156 | net_dec_ingress_queue(); | |
e687ad60 | 157 | #endif |
d1c85c2e | 158 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 159 | static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]); |
a2d7ec58 | 160 | #endif |
f6ebe77f | 161 | synchronize_net(); |
bd3769bf | 162 | nf_queue_nf_hook_drop(net, p); |
514ed62e FW |
163 | /* other cpu might still process nfqueue verdict that used reg */ |
164 | synchronize_net(); | |
bd3769bf | 165 | kfree(p); |
085db2c0 EB |
166 | } |
167 | EXPORT_SYMBOL(nf_unregister_net_hook); | |
168 | ||
169 | int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, | |
170 | unsigned int n) | |
171 | { | |
172 | unsigned int i; | |
173 | int err = 0; | |
174 | ||
175 | for (i = 0; i < n; i++) { | |
176 | err = nf_register_net_hook(net, ®[i]); | |
177 | if (err) | |
178 | goto err; | |
179 | } | |
180 | return err; | |
181 | ||
182 | err: | |
183 | if (i > 0) | |
184 | nf_unregister_net_hooks(net, reg, i); | |
185 | return err; | |
186 | } | |
187 | EXPORT_SYMBOL(nf_register_net_hooks); | |
188 | ||
189 | void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, | |
190 | unsigned int n) | |
191 | { | |
192 | while (n-- > 0) | |
193 | nf_unregister_net_hook(net, ®[n]); | |
194 | } | |
195 | EXPORT_SYMBOL(nf_unregister_net_hooks); | |
196 | ||
197 | static LIST_HEAD(nf_hook_list); | |
198 | ||
e8bffe0c | 199 | static int _nf_register_hook(struct nf_hook_ops *reg) |
085db2c0 EB |
200 | { |
201 | struct net *net, *last; | |
202 | int ret; | |
203 | ||
085db2c0 EB |
204 | for_each_net(net) { |
205 | ret = nf_register_net_hook(net, reg); | |
206 | if (ret && ret != -ENOENT) | |
207 | goto rollback; | |
208 | } | |
209 | list_add_tail(®->list, &nf_hook_list); | |
085db2c0 EB |
210 | |
211 | return 0; | |
212 | rollback: | |
213 | last = net; | |
214 | for_each_net(net) { | |
215 | if (net == last) | |
216 | break; | |
217 | nf_unregister_net_hook(net, reg); | |
218 | } | |
e8bffe0c MB |
219 | return ret; |
220 | } | |
221 | ||
222 | int nf_register_hook(struct nf_hook_ops *reg) | |
223 | { | |
224 | int ret; | |
225 | ||
226 | rtnl_lock(); | |
227 | ret = _nf_register_hook(reg); | |
085db2c0 | 228 | rtnl_unlock(); |
e8bffe0c | 229 | |
085db2c0 EB |
230 | return ret; |
231 | } | |
232 | EXPORT_SYMBOL(nf_register_hook); | |
233 | ||
e8bffe0c | 234 | static void _nf_unregister_hook(struct nf_hook_ops *reg) |
085db2c0 EB |
235 | { |
236 | struct net *net; | |
237 | ||
085db2c0 EB |
238 | list_del(®->list); |
239 | for_each_net(net) | |
240 | nf_unregister_net_hook(net, reg); | |
e8bffe0c MB |
241 | } |
242 | ||
243 | void nf_unregister_hook(struct nf_hook_ops *reg) | |
244 | { | |
245 | rtnl_lock(); | |
246 | _nf_unregister_hook(reg); | |
085db2c0 | 247 | rtnl_unlock(); |
f6ebe77f HW |
248 | } |
249 | EXPORT_SYMBOL(nf_unregister_hook); | |
250 | ||
972d1cb1 PM |
251 | int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n) |
252 | { | |
253 | unsigned int i; | |
254 | int err = 0; | |
255 | ||
256 | for (i = 0; i < n; i++) { | |
257 | err = nf_register_hook(®[i]); | |
258 | if (err) | |
259 | goto err; | |
260 | } | |
261 | return err; | |
262 | ||
263 | err: | |
264 | if (i > 0) | |
265 | nf_unregister_hooks(reg, i); | |
266 | return err; | |
267 | } | |
268 | EXPORT_SYMBOL(nf_register_hooks); | |
269 | ||
e8bffe0c MB |
270 | /* Caller MUST take rtnl_lock() */ |
271 | int _nf_register_hooks(struct nf_hook_ops *reg, unsigned int n) | |
272 | { | |
273 | unsigned int i; | |
274 | int err = 0; | |
275 | ||
276 | for (i = 0; i < n; i++) { | |
277 | err = _nf_register_hook(®[i]); | |
278 | if (err) | |
279 | goto err; | |
280 | } | |
281 | return err; | |
282 | ||
283 | err: | |
284 | if (i > 0) | |
285 | _nf_unregister_hooks(reg, i); | |
286 | return err; | |
287 | } | |
288 | EXPORT_SYMBOL(_nf_register_hooks); | |
289 | ||
972d1cb1 PM |
290 | void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n) |
291 | { | |
f68c5301 CG |
292 | while (n-- > 0) |
293 | nf_unregister_hook(®[n]); | |
972d1cb1 PM |
294 | } |
295 | EXPORT_SYMBOL(nf_unregister_hooks); | |
296 | ||
e8bffe0c MB |
297 | /* Caller MUST take rtnl_lock */ |
298 | void _nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n) | |
299 | { | |
300 | while (n-- > 0) | |
301 | _nf_unregister_hook(®[n]); | |
302 | } | |
303 | EXPORT_SYMBOL(_nf_unregister_hooks); | |
304 | ||
f6ebe77f | 305 | /* Returns 1 if okfn() needs to be executed by the caller, |
e2361cb9 | 306 | * -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */ |
01886bd9 PNA |
307 | int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, |
308 | struct nf_hook_entry *entry) | |
f6ebe77f | 309 | { |
f6ebe77f | 310 | unsigned int verdict; |
c63cbc46 | 311 | int ret; |
f6ebe77f | 312 | |
26dfab72 PNA |
313 | do { |
314 | verdict = entry->ops.hook(entry->ops.priv, skb, state); | |
315 | switch (verdict & NF_VERDICT_MASK) { | |
316 | case NF_ACCEPT: | |
317 | entry = rcu_dereference(entry->next); | |
318 | break; | |
319 | case NF_DROP: | |
320 | kfree_skb(skb); | |
321 | ret = NF_DROP_GETERR(verdict); | |
322 | if (ret == 0) | |
323 | ret = -EPERM; | |
324 | return ret; | |
26dfab72 PNA |
325 | case NF_QUEUE: |
326 | ret = nf_queue(skb, state, &entry, verdict); | |
327 | if (ret == 1 && entry) | |
328 | continue; | |
329 | return ret; | |
330 | default: | |
331 | /* Implicit handling for NF_STOLEN, as well as any other | |
332 | * non conventional verdicts. | |
333 | */ | |
334 | return 0; | |
335 | } | |
336 | } while (entry); | |
337 | ||
338 | return 1; | |
f6ebe77f HW |
339 | } |
340 | EXPORT_SYMBOL(nf_hook_slow); | |
341 | ||
342 | ||
37d41879 | 343 | int skb_make_writable(struct sk_buff *skb, unsigned int writable_len) |
f6ebe77f | 344 | { |
37d41879 | 345 | if (writable_len > skb->len) |
f6ebe77f HW |
346 | return 0; |
347 | ||
348 | /* Not exclusive use of packet? Must copy. */ | |
37d41879 HX |
349 | if (!skb_cloned(skb)) { |
350 | if (writable_len <= skb_headlen(skb)) | |
351 | return 1; | |
352 | } else if (skb_clone_writable(skb, writable_len)) | |
353 | return 1; | |
354 | ||
355 | if (writable_len <= skb_headlen(skb)) | |
356 | writable_len = 0; | |
357 | else | |
358 | writable_len -= skb_headlen(skb); | |
359 | ||
360 | return !!__pskb_pull_tail(skb, writable_len); | |
f6ebe77f HW |
361 | } |
362 | EXPORT_SYMBOL(skb_make_writable); | |
363 | ||
b7bd1809 PNA |
364 | /* This needs to be compiled in any case to avoid dependencies between the |
365 | * nfnetlink_queue code and nf_conntrack. | |
366 | */ | |
a4b4766c KM |
367 | struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly; |
368 | EXPORT_SYMBOL_GPL(nfnl_ct_hook); | |
b7bd1809 | 369 | |
c0cd1156 | 370 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
f6ebe77f HW |
371 | /* This does not belong here, but locally generated errors need it if connection |
372 | tracking in use: without this, connection may not be in hash table, and hence | |
373 | manufactured ICMP or RST packets will not be associated with it. */ | |
312a0c16 PM |
374 | void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) |
375 | __rcu __read_mostly; | |
f6ebe77f HW |
376 | EXPORT_SYMBOL(ip_ct_attach); |
377 | ||
312a0c16 | 378 | void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb) |
f6ebe77f | 379 | { |
312a0c16 | 380 | void (*attach)(struct sk_buff *, const struct sk_buff *); |
f6ebe77f | 381 | |
c3a47ab3 PM |
382 | if (skb->nfct) { |
383 | rcu_read_lock(); | |
384 | attach = rcu_dereference(ip_ct_attach); | |
385 | if (attach) | |
386 | attach(new, skb); | |
387 | rcu_read_unlock(); | |
f6ebe77f HW |
388 | } |
389 | } | |
390 | EXPORT_SYMBOL(nf_ct_attach); | |
de6e05c4 | 391 | |
0e60ebe0 | 392 | void (*nf_ct_destroy)(struct nf_conntrack *) __rcu __read_mostly; |
de6e05c4 YK |
393 | EXPORT_SYMBOL(nf_ct_destroy); |
394 | ||
395 | void nf_conntrack_destroy(struct nf_conntrack *nfct) | |
396 | { | |
397 | void (*destroy)(struct nf_conntrack *); | |
398 | ||
399 | rcu_read_lock(); | |
400 | destroy = rcu_dereference(nf_ct_destroy); | |
401 | BUG_ON(destroy == NULL); | |
402 | destroy(nfct); | |
403 | rcu_read_unlock(); | |
404 | } | |
405 | EXPORT_SYMBOL(nf_conntrack_destroy); | |
9cb01766 | 406 | |
62da9865 DB |
407 | /* Built-in default zone used e.g. by modules. */ |
408 | const struct nf_conntrack_zone nf_ct_zone_dflt = { | |
409 | .id = NF_CT_DEFAULT_ZONE_ID, | |
410 | .dir = NF_CT_DEFAULT_ZONE_DIR, | |
411 | }; | |
412 | EXPORT_SYMBOL_GPL(nf_ct_zone_dflt); | |
de6e05c4 | 413 | #endif /* CONFIG_NF_CONNTRACK */ |
f6ebe77f | 414 | |
c7232c99 PM |
415 | #ifdef CONFIG_NF_NAT_NEEDED |
416 | void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *); | |
417 | EXPORT_SYMBOL(nf_nat_decode_session_hook); | |
418 | #endif | |
419 | ||
085db2c0 EB |
420 | static int nf_register_hook_list(struct net *net) |
421 | { | |
422 | struct nf_hook_ops *elem; | |
423 | int ret; | |
424 | ||
425 | rtnl_lock(); | |
426 | list_for_each_entry(elem, &nf_hook_list, list) { | |
427 | ret = nf_register_net_hook(net, elem); | |
428 | if (ret && ret != -ENOENT) | |
429 | goto out_undo; | |
430 | } | |
431 | rtnl_unlock(); | |
432 | return 0; | |
433 | ||
434 | out_undo: | |
435 | list_for_each_entry_continue_reverse(elem, &nf_hook_list, list) | |
436 | nf_unregister_net_hook(net, elem); | |
437 | rtnl_unlock(); | |
438 | return ret; | |
439 | } | |
440 | ||
441 | static void nf_unregister_hook_list(struct net *net) | |
442 | { | |
443 | struct nf_hook_ops *elem; | |
444 | ||
445 | rtnl_lock(); | |
446 | list_for_each_entry(elem, &nf_hook_list, list) | |
447 | nf_unregister_net_hook(net, elem); | |
448 | rtnl_unlock(); | |
449 | } | |
450 | ||
f3c1a44a G |
451 | static int __net_init netfilter_net_init(struct net *net) |
452 | { | |
085db2c0 EB |
453 | int i, h, ret; |
454 | ||
455 | for (i = 0; i < ARRAY_SIZE(net->nf.hooks); i++) { | |
456 | for (h = 0; h < NF_MAX_HOOKS; h++) | |
e3b37f11 | 457 | RCU_INIT_POINTER(net->nf.hooks[i][h], NULL); |
085db2c0 EB |
458 | } |
459 | ||
f3c1a44a G |
460 | #ifdef CONFIG_PROC_FS |
461 | net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter", | |
462 | net->proc_net); | |
12202fa7 PNA |
463 | if (!net->nf.proc_netfilter) { |
464 | if (!net_eq(net, &init_net)) | |
465 | pr_err("cannot create netfilter proc entry"); | |
466 | ||
f3c1a44a G |
467 | return -ENOMEM; |
468 | } | |
469 | #endif | |
085db2c0 EB |
470 | ret = nf_register_hook_list(net); |
471 | if (ret) | |
472 | remove_proc_entry("netfilter", net->proc_net); | |
473 | ||
474 | return ret; | |
f3c1a44a G |
475 | } |
476 | ||
477 | static void __net_exit netfilter_net_exit(struct net *net) | |
478 | { | |
085db2c0 | 479 | nf_unregister_hook_list(net); |
f3c1a44a G |
480 | remove_proc_entry("netfilter", net->proc_net); |
481 | } | |
482 | ||
483 | static struct pernet_operations netfilter_net_ops = { | |
484 | .init = netfilter_net_init, | |
485 | .exit = netfilter_net_exit, | |
486 | }; | |
487 | ||
6d11cfdb | 488 | int __init netfilter_init(void) |
f6ebe77f | 489 | { |
085db2c0 | 490 | int ret; |
f6ebe77f | 491 | |
6d11cfdb PNA |
492 | ret = register_pernet_subsys(&netfilter_net_ops); |
493 | if (ret < 0) | |
494 | goto err; | |
495 | ||
496 | ret = netfilter_log_init(); | |
497 | if (ret < 0) | |
498 | goto err_pernet; | |
f6ebe77f | 499 | |
6d11cfdb PNA |
500 | return 0; |
501 | err_pernet: | |
502 | unregister_pernet_subsys(&netfilter_net_ops); | |
503 | err: | |
504 | return ret; | |
f6ebe77f | 505 | } |