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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 | |
0aa8c57a | 105 | nf_hook_entry_init(entry, reg); |
e3b37f11 AC |
106 | |
107 | mutex_lock(&nf_hook_mutex); | |
085db2c0 | 108 | |
bd3769bf | 109 | /* Find the spot in the list */ |
679972f3 | 110 | for (; (p = nf_entry_dereference(*pp)) != NULL; pp = &p->next) { |
0aa8c57a | 111 | if (reg->priority < nf_hook_entry_priority(p)) |
bd3769bf | 112 | break; |
f6ebe77f | 113 | } |
bd3769bf LT |
114 | rcu_assign_pointer(entry->next, p); |
115 | rcu_assign_pointer(*pp, entry); | |
e3b37f11 | 116 | |
fd706d69 | 117 | mutex_unlock(&nf_hook_mutex); |
4c091156 EB |
118 | #ifdef CONFIG_NETFILTER_INGRESS |
119 | if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) | |
120 | net_inc_ingress_queue(); | |
121 | #endif | |
d1c85c2e | 122 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 123 | static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]); |
a2d7ec58 | 124 | #endif |
f6ebe77f HW |
125 | return 0; |
126 | } | |
085db2c0 | 127 | EXPORT_SYMBOL(nf_register_net_hook); |
f6ebe77f | 128 | |
085db2c0 | 129 | void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg) |
f6ebe77f | 130 | { |
bd3769bf LT |
131 | struct nf_hook_entry __rcu **pp; |
132 | struct nf_hook_entry *p; | |
133 | ||
134 | pp = nf_hook_entry_head(net, reg); | |
135 | if (WARN_ON_ONCE(!pp)) | |
136 | return; | |
085db2c0 | 137 | |
fd706d69 | 138 | mutex_lock(&nf_hook_mutex); |
679972f3 | 139 | for (; (p = nf_entry_dereference(*pp)) != NULL; pp = &p->next) { |
0aa8c57a | 140 | if (nf_hook_entry_ops(p) == reg) { |
bd3769bf LT |
141 | rcu_assign_pointer(*pp, p->next); |
142 | break; | |
085db2c0 EB |
143 | } |
144 | } | |
fd706d69 | 145 | mutex_unlock(&nf_hook_mutex); |
bd3769bf | 146 | if (!p) { |
085db2c0 EB |
147 | WARN(1, "nf_unregister_net_hook: hook not found!\n"); |
148 | return; | |
149 | } | |
e687ad60 | 150 | #ifdef CONFIG_NETFILTER_INGRESS |
4c091156 EB |
151 | if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) |
152 | net_dec_ingress_queue(); | |
e687ad60 | 153 | #endif |
d1c85c2e | 154 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 155 | static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]); |
a2d7ec58 | 156 | #endif |
f6ebe77f | 157 | synchronize_net(); |
bd3769bf | 158 | nf_queue_nf_hook_drop(net, p); |
514ed62e FW |
159 | /* other cpu might still process nfqueue verdict that used reg */ |
160 | synchronize_net(); | |
bd3769bf | 161 | kfree(p); |
085db2c0 EB |
162 | } |
163 | EXPORT_SYMBOL(nf_unregister_net_hook); | |
164 | ||
165 | int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, | |
166 | unsigned int n) | |
167 | { | |
168 | unsigned int i; | |
169 | int err = 0; | |
170 | ||
171 | for (i = 0; i < n; i++) { | |
172 | err = nf_register_net_hook(net, ®[i]); | |
173 | if (err) | |
174 | goto err; | |
175 | } | |
176 | return err; | |
177 | ||
178 | err: | |
179 | if (i > 0) | |
180 | nf_unregister_net_hooks(net, reg, i); | |
181 | return err; | |
182 | } | |
183 | EXPORT_SYMBOL(nf_register_net_hooks); | |
184 | ||
185 | void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, | |
186 | unsigned int n) | |
187 | { | |
188 | while (n-- > 0) | |
189 | nf_unregister_net_hook(net, ®[n]); | |
190 | } | |
191 | EXPORT_SYMBOL(nf_unregister_net_hooks); | |
192 | ||
193 | static LIST_HEAD(nf_hook_list); | |
194 | ||
e8bffe0c | 195 | static int _nf_register_hook(struct nf_hook_ops *reg) |
085db2c0 EB |
196 | { |
197 | struct net *net, *last; | |
198 | int ret; | |
199 | ||
085db2c0 EB |
200 | for_each_net(net) { |
201 | ret = nf_register_net_hook(net, reg); | |
202 | if (ret && ret != -ENOENT) | |
203 | goto rollback; | |
204 | } | |
205 | list_add_tail(®->list, &nf_hook_list); | |
085db2c0 EB |
206 | |
207 | return 0; | |
208 | rollback: | |
209 | last = net; | |
210 | for_each_net(net) { | |
211 | if (net == last) | |
212 | break; | |
213 | nf_unregister_net_hook(net, reg); | |
214 | } | |
e8bffe0c MB |
215 | return ret; |
216 | } | |
217 | ||
218 | int nf_register_hook(struct nf_hook_ops *reg) | |
219 | { | |
220 | int ret; | |
221 | ||
222 | rtnl_lock(); | |
223 | ret = _nf_register_hook(reg); | |
085db2c0 | 224 | rtnl_unlock(); |
e8bffe0c | 225 | |
085db2c0 EB |
226 | return ret; |
227 | } | |
228 | EXPORT_SYMBOL(nf_register_hook); | |
229 | ||
e8bffe0c | 230 | static void _nf_unregister_hook(struct nf_hook_ops *reg) |
085db2c0 EB |
231 | { |
232 | struct net *net; | |
233 | ||
085db2c0 EB |
234 | list_del(®->list); |
235 | for_each_net(net) | |
236 | nf_unregister_net_hook(net, reg); | |
e8bffe0c MB |
237 | } |
238 | ||
239 | void nf_unregister_hook(struct nf_hook_ops *reg) | |
240 | { | |
241 | rtnl_lock(); | |
242 | _nf_unregister_hook(reg); | |
085db2c0 | 243 | rtnl_unlock(); |
f6ebe77f HW |
244 | } |
245 | EXPORT_SYMBOL(nf_unregister_hook); | |
246 | ||
972d1cb1 PM |
247 | int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n) |
248 | { | |
249 | unsigned int i; | |
250 | int err = 0; | |
251 | ||
252 | for (i = 0; i < n; i++) { | |
253 | err = nf_register_hook(®[i]); | |
254 | if (err) | |
255 | goto err; | |
256 | } | |
257 | return err; | |
258 | ||
259 | err: | |
260 | if (i > 0) | |
261 | nf_unregister_hooks(reg, i); | |
262 | return err; | |
263 | } | |
264 | EXPORT_SYMBOL(nf_register_hooks); | |
265 | ||
e8bffe0c MB |
266 | /* Caller MUST take rtnl_lock() */ |
267 | int _nf_register_hooks(struct nf_hook_ops *reg, unsigned int n) | |
268 | { | |
269 | unsigned int i; | |
270 | int err = 0; | |
271 | ||
272 | for (i = 0; i < n; i++) { | |
273 | err = _nf_register_hook(®[i]); | |
274 | if (err) | |
275 | goto err; | |
276 | } | |
277 | return err; | |
278 | ||
279 | err: | |
280 | if (i > 0) | |
281 | _nf_unregister_hooks(reg, i); | |
282 | return err; | |
283 | } | |
284 | EXPORT_SYMBOL(_nf_register_hooks); | |
285 | ||
972d1cb1 PM |
286 | void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n) |
287 | { | |
f68c5301 CG |
288 | while (n-- > 0) |
289 | nf_unregister_hook(®[n]); | |
972d1cb1 PM |
290 | } |
291 | EXPORT_SYMBOL(nf_unregister_hooks); | |
292 | ||
e8bffe0c MB |
293 | /* Caller MUST take rtnl_lock */ |
294 | void _nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n) | |
295 | { | |
296 | while (n-- > 0) | |
297 | _nf_unregister_hook(®[n]); | |
298 | } | |
299 | EXPORT_SYMBOL(_nf_unregister_hooks); | |
300 | ||
f6ebe77f | 301 | /* Returns 1 if okfn() needs to be executed by the caller, |
e2361cb9 | 302 | * -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */ |
01886bd9 PNA |
303 | int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, |
304 | struct nf_hook_entry *entry) | |
f6ebe77f | 305 | { |
f6ebe77f | 306 | unsigned int verdict; |
c63cbc46 | 307 | int ret; |
f6ebe77f | 308 | |
26dfab72 | 309 | do { |
0aa8c57a | 310 | verdict = nf_hook_entry_hookfn(entry, skb, state); |
26dfab72 PNA |
311 | switch (verdict & NF_VERDICT_MASK) { |
312 | case NF_ACCEPT: | |
313 | entry = rcu_dereference(entry->next); | |
314 | break; | |
315 | case NF_DROP: | |
316 | kfree_skb(skb); | |
317 | ret = NF_DROP_GETERR(verdict); | |
318 | if (ret == 0) | |
319 | ret = -EPERM; | |
320 | return ret; | |
26dfab72 PNA |
321 | case NF_QUEUE: |
322 | ret = nf_queue(skb, state, &entry, verdict); | |
323 | if (ret == 1 && entry) | |
324 | continue; | |
325 | return ret; | |
326 | default: | |
327 | /* Implicit handling for NF_STOLEN, as well as any other | |
328 | * non conventional verdicts. | |
329 | */ | |
330 | return 0; | |
331 | } | |
332 | } while (entry); | |
333 | ||
334 | return 1; | |
f6ebe77f HW |
335 | } |
336 | EXPORT_SYMBOL(nf_hook_slow); | |
337 | ||
338 | ||
37d41879 | 339 | int skb_make_writable(struct sk_buff *skb, unsigned int writable_len) |
f6ebe77f | 340 | { |
37d41879 | 341 | if (writable_len > skb->len) |
f6ebe77f HW |
342 | return 0; |
343 | ||
344 | /* Not exclusive use of packet? Must copy. */ | |
37d41879 HX |
345 | if (!skb_cloned(skb)) { |
346 | if (writable_len <= skb_headlen(skb)) | |
347 | return 1; | |
348 | } else if (skb_clone_writable(skb, writable_len)) | |
349 | return 1; | |
350 | ||
351 | if (writable_len <= skb_headlen(skb)) | |
352 | writable_len = 0; | |
353 | else | |
354 | writable_len -= skb_headlen(skb); | |
355 | ||
356 | return !!__pskb_pull_tail(skb, writable_len); | |
f6ebe77f HW |
357 | } |
358 | EXPORT_SYMBOL(skb_make_writable); | |
359 | ||
b7bd1809 PNA |
360 | /* This needs to be compiled in any case to avoid dependencies between the |
361 | * nfnetlink_queue code and nf_conntrack. | |
362 | */ | |
a4b4766c KM |
363 | struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly; |
364 | EXPORT_SYMBOL_GPL(nfnl_ct_hook); | |
b7bd1809 | 365 | |
c0cd1156 | 366 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
f6ebe77f HW |
367 | /* This does not belong here, but locally generated errors need it if connection |
368 | tracking in use: without this, connection may not be in hash table, and hence | |
369 | manufactured ICMP or RST packets will not be associated with it. */ | |
312a0c16 PM |
370 | void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) |
371 | __rcu __read_mostly; | |
f6ebe77f HW |
372 | EXPORT_SYMBOL(ip_ct_attach); |
373 | ||
312a0c16 | 374 | void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb) |
f6ebe77f | 375 | { |
312a0c16 | 376 | void (*attach)(struct sk_buff *, const struct sk_buff *); |
f6ebe77f | 377 | |
c3a47ab3 PM |
378 | if (skb->nfct) { |
379 | rcu_read_lock(); | |
380 | attach = rcu_dereference(ip_ct_attach); | |
381 | if (attach) | |
382 | attach(new, skb); | |
383 | rcu_read_unlock(); | |
f6ebe77f HW |
384 | } |
385 | } | |
386 | EXPORT_SYMBOL(nf_ct_attach); | |
de6e05c4 | 387 | |
0e60ebe0 | 388 | void (*nf_ct_destroy)(struct nf_conntrack *) __rcu __read_mostly; |
de6e05c4 YK |
389 | EXPORT_SYMBOL(nf_ct_destroy); |
390 | ||
391 | void nf_conntrack_destroy(struct nf_conntrack *nfct) | |
392 | { | |
393 | void (*destroy)(struct nf_conntrack *); | |
394 | ||
395 | rcu_read_lock(); | |
396 | destroy = rcu_dereference(nf_ct_destroy); | |
397 | BUG_ON(destroy == NULL); | |
398 | destroy(nfct); | |
399 | rcu_read_unlock(); | |
400 | } | |
401 | EXPORT_SYMBOL(nf_conntrack_destroy); | |
9cb01766 | 402 | |
62da9865 DB |
403 | /* Built-in default zone used e.g. by modules. */ |
404 | const struct nf_conntrack_zone nf_ct_zone_dflt = { | |
405 | .id = NF_CT_DEFAULT_ZONE_ID, | |
406 | .dir = NF_CT_DEFAULT_ZONE_DIR, | |
407 | }; | |
408 | EXPORT_SYMBOL_GPL(nf_ct_zone_dflt); | |
de6e05c4 | 409 | #endif /* CONFIG_NF_CONNTRACK */ |
f6ebe77f | 410 | |
c7232c99 PM |
411 | #ifdef CONFIG_NF_NAT_NEEDED |
412 | void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *); | |
413 | EXPORT_SYMBOL(nf_nat_decode_session_hook); | |
414 | #endif | |
415 | ||
085db2c0 EB |
416 | static int nf_register_hook_list(struct net *net) |
417 | { | |
418 | struct nf_hook_ops *elem; | |
419 | int ret; | |
420 | ||
421 | rtnl_lock(); | |
422 | list_for_each_entry(elem, &nf_hook_list, list) { | |
423 | ret = nf_register_net_hook(net, elem); | |
424 | if (ret && ret != -ENOENT) | |
425 | goto out_undo; | |
426 | } | |
427 | rtnl_unlock(); | |
428 | return 0; | |
429 | ||
430 | out_undo: | |
431 | list_for_each_entry_continue_reverse(elem, &nf_hook_list, list) | |
432 | nf_unregister_net_hook(net, elem); | |
433 | rtnl_unlock(); | |
434 | return ret; | |
435 | } | |
436 | ||
437 | static void nf_unregister_hook_list(struct net *net) | |
438 | { | |
439 | struct nf_hook_ops *elem; | |
440 | ||
441 | rtnl_lock(); | |
442 | list_for_each_entry(elem, &nf_hook_list, list) | |
443 | nf_unregister_net_hook(net, elem); | |
444 | rtnl_unlock(); | |
445 | } | |
446 | ||
f3c1a44a G |
447 | static int __net_init netfilter_net_init(struct net *net) |
448 | { | |
085db2c0 EB |
449 | int i, h, ret; |
450 | ||
451 | for (i = 0; i < ARRAY_SIZE(net->nf.hooks); i++) { | |
452 | for (h = 0; h < NF_MAX_HOOKS; h++) | |
e3b37f11 | 453 | RCU_INIT_POINTER(net->nf.hooks[i][h], NULL); |
085db2c0 EB |
454 | } |
455 | ||
f3c1a44a G |
456 | #ifdef CONFIG_PROC_FS |
457 | net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter", | |
458 | net->proc_net); | |
12202fa7 PNA |
459 | if (!net->nf.proc_netfilter) { |
460 | if (!net_eq(net, &init_net)) | |
461 | pr_err("cannot create netfilter proc entry"); | |
462 | ||
f3c1a44a G |
463 | return -ENOMEM; |
464 | } | |
465 | #endif | |
085db2c0 EB |
466 | ret = nf_register_hook_list(net); |
467 | if (ret) | |
468 | remove_proc_entry("netfilter", net->proc_net); | |
469 | ||
470 | return ret; | |
f3c1a44a G |
471 | } |
472 | ||
473 | static void __net_exit netfilter_net_exit(struct net *net) | |
474 | { | |
085db2c0 | 475 | nf_unregister_hook_list(net); |
f3c1a44a G |
476 | remove_proc_entry("netfilter", net->proc_net); |
477 | } | |
478 | ||
479 | static struct pernet_operations netfilter_net_ops = { | |
480 | .init = netfilter_net_init, | |
481 | .exit = netfilter_net_exit, | |
482 | }; | |
483 | ||
6d11cfdb | 484 | int __init netfilter_init(void) |
f6ebe77f | 485 | { |
085db2c0 | 486 | int ret; |
f6ebe77f | 487 | |
6d11cfdb PNA |
488 | ret = register_pernet_subsys(&netfilter_net_ops); |
489 | if (ret < 0) | |
490 | goto err; | |
491 | ||
492 | ret = netfilter_log_init(); | |
493 | if (ret < 0) | |
494 | goto err_pernet; | |
f6ebe77f | 495 | |
6d11cfdb PNA |
496 | return 0; |
497 | err_pernet: | |
498 | unregister_pernet_subsys(&netfilter_net_ops); | |
499 | err: | |
500 | return ret; | |
f6ebe77f | 501 | } |