]>
Commit | Line | Data |
---|---|---|
12f7a505 PNA |
1 | /* |
2 | * (C) 2012 Pablo Neira Ayuso <pablo@netfilter.org> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation (or any later at your option). | |
7 | * | |
8 | * This software has been sponsored by Vyatta Inc. <http://www.vyatta.com> | |
9 | */ | |
10 | #include <linux/init.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/skbuff.h> | |
14 | #include <linux/netlink.h> | |
15 | #include <linux/rculist.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/types.h> | |
18 | #include <linux/list.h> | |
19 | #include <linux/errno.h> | |
20 | #include <net/netlink.h> | |
21 | #include <net/sock.h> | |
22 | ||
23 | #include <net/netfilter/nf_conntrack_helper.h> | |
24 | #include <net/netfilter/nf_conntrack_expect.h> | |
25 | #include <net/netfilter/nf_conntrack_ecache.h> | |
26 | ||
27 | #include <linux/netfilter/nfnetlink.h> | |
28 | #include <linux/netfilter/nfnetlink_conntrack.h> | |
29 | #include <linux/netfilter/nfnetlink_cthelper.h> | |
30 | ||
31 | MODULE_LICENSE("GPL"); | |
32 | MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); | |
33 | MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers"); | |
34 | ||
35 | static int | |
36 | nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff, | |
37 | struct nf_conn *ct, enum ip_conntrack_info ctinfo) | |
38 | { | |
39 | const struct nf_conn_help *help; | |
40 | struct nf_conntrack_helper *helper; | |
41 | ||
42 | help = nfct_help(ct); | |
43 | if (help == NULL) | |
44 | return NF_DROP; | |
45 | ||
46 | /* rcu_read_lock()ed by nf_hook_slow */ | |
47 | helper = rcu_dereference(help->helper); | |
48 | if (helper == NULL) | |
49 | return NF_DROP; | |
50 | ||
51 | /* This is an user-space helper not yet configured, skip. */ | |
52 | if ((helper->flags & | |
53 | (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) == | |
54 | NF_CT_HELPER_F_USERSPACE) | |
55 | return NF_ACCEPT; | |
56 | ||
57 | /* If the user-space helper is not available, don't block traffic. */ | |
58 | return NF_QUEUE_NR(helper->queue_num) | NF_VERDICT_FLAG_QUEUE_BYPASS; | |
59 | } | |
60 | ||
61 | static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = { | |
62 | [NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, }, | |
63 | [NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, }, | |
64 | }; | |
65 | ||
66 | static int | |
67 | nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple, | |
68 | const struct nlattr *attr) | |
69 | { | |
70 | struct nlattr *tb[NFCTH_TUPLE_MAX+1]; | |
71 | ||
72 | nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr, nfnl_cthelper_tuple_pol); | |
73 | ||
74 | if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM]) | |
75 | return -EINVAL; | |
76 | ||
77 | tuple->src.l3num = ntohs(nla_get_u16(tb[NFCTH_TUPLE_L3PROTONUM])); | |
78 | tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]); | |
79 | ||
80 | return 0; | |
81 | } | |
82 | ||
83 | static int | |
84 | nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct) | |
85 | { | |
86 | const struct nf_conn_help *help = nfct_help(ct); | |
87 | ||
88 | if (help->helper->data_len == 0) | |
89 | return -EINVAL; | |
90 | ||
91 | memcpy(&help->data, nla_data(attr), help->helper->data_len); | |
92 | return 0; | |
93 | } | |
94 | ||
95 | static int | |
96 | nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct) | |
97 | { | |
98 | const struct nf_conn_help *help = nfct_help(ct); | |
99 | ||
100 | if (help->helper->data_len && | |
101 | nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data)) | |
102 | goto nla_put_failure; | |
103 | ||
104 | return 0; | |
105 | ||
106 | nla_put_failure: | |
107 | return -ENOSPC; | |
108 | } | |
109 | ||
110 | static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = { | |
111 | [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING, | |
112 | .len = NF_CT_HELPER_NAME_LEN-1 }, | |
113 | [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, }, | |
114 | [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, }, | |
115 | }; | |
116 | ||
117 | static int | |
118 | nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy, | |
119 | const struct nlattr *attr) | |
120 | { | |
121 | struct nlattr *tb[NFCTH_POLICY_MAX+1]; | |
122 | ||
123 | nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol); | |
124 | ||
125 | if (!tb[NFCTH_POLICY_NAME] || | |
126 | !tb[NFCTH_POLICY_EXPECT_MAX] || | |
127 | !tb[NFCTH_POLICY_EXPECT_TIMEOUT]) | |
128 | return -EINVAL; | |
129 | ||
130 | strncpy(expect_policy->name, | |
131 | nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN); | |
132 | expect_policy->max_expected = | |
133 | ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX])); | |
134 | expect_policy->timeout = | |
135 | ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT])); | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
140 | static const struct nla_policy | |
141 | nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = { | |
142 | [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, }, | |
143 | }; | |
144 | ||
145 | static int | |
146 | nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper, | |
147 | const struct nlattr *attr) | |
148 | { | |
149 | int i, ret; | |
150 | struct nf_conntrack_expect_policy *expect_policy; | |
151 | struct nlattr *tb[NFCTH_POLICY_SET_MAX+1]; | |
152 | ||
153 | nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr, | |
154 | nfnl_cthelper_expect_policy_set); | |
155 | ||
156 | if (!tb[NFCTH_POLICY_SET_NUM]) | |
157 | return -EINVAL; | |
158 | ||
159 | helper->expect_class_max = | |
160 | ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM])); | |
161 | ||
162 | if (helper->expect_class_max != 0 && | |
163 | helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES) | |
164 | return -EOVERFLOW; | |
165 | ||
166 | expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) * | |
167 | helper->expect_class_max, GFP_KERNEL); | |
168 | if (expect_policy == NULL) | |
169 | return -ENOMEM; | |
170 | ||
171 | for (i=0; i<helper->expect_class_max; i++) { | |
172 | if (!tb[NFCTH_POLICY_SET+i]) | |
173 | goto err; | |
174 | ||
175 | ret = nfnl_cthelper_expect_policy(&expect_policy[i], | |
176 | tb[NFCTH_POLICY_SET+i]); | |
177 | if (ret < 0) | |
178 | goto err; | |
179 | } | |
180 | helper->expect_policy = expect_policy; | |
181 | return 0; | |
182 | err: | |
183 | kfree(expect_policy); | |
184 | return -EINVAL; | |
185 | } | |
186 | ||
187 | static int | |
188 | nfnl_cthelper_create(const struct nlattr * const tb[], | |
189 | struct nf_conntrack_tuple *tuple) | |
190 | { | |
191 | struct nf_conntrack_helper *helper; | |
192 | int ret; | |
193 | ||
194 | if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN]) | |
195 | return -EINVAL; | |
196 | ||
197 | helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL); | |
198 | if (helper == NULL) | |
199 | return -ENOMEM; | |
200 | ||
201 | ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]); | |
202 | if (ret < 0) | |
203 | goto err; | |
204 | ||
205 | strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN); | |
206 | helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN])); | |
207 | helper->flags |= NF_CT_HELPER_F_USERSPACE; | |
208 | memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple)); | |
209 | ||
210 | helper->me = THIS_MODULE; | |
211 | helper->help = nfnl_userspace_cthelper; | |
212 | helper->from_nlattr = nfnl_cthelper_from_nlattr; | |
213 | helper->to_nlattr = nfnl_cthelper_to_nlattr; | |
214 | ||
215 | /* Default to queue number zero, this can be updated at any time. */ | |
216 | if (tb[NFCTH_QUEUE_NUM]) | |
217 | helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM])); | |
218 | ||
219 | if (tb[NFCTH_STATUS]) { | |
220 | int status = ntohl(nla_get_be32(tb[NFCTH_STATUS])); | |
221 | ||
222 | switch(status) { | |
223 | case NFCT_HELPER_STATUS_ENABLED: | |
224 | helper->flags |= NF_CT_HELPER_F_CONFIGURED; | |
225 | break; | |
226 | case NFCT_HELPER_STATUS_DISABLED: | |
227 | helper->flags &= ~NF_CT_HELPER_F_CONFIGURED; | |
228 | break; | |
229 | } | |
230 | } | |
231 | ||
232 | ret = nf_conntrack_helper_register(helper); | |
233 | if (ret < 0) | |
234 | goto err; | |
235 | ||
236 | return 0; | |
237 | err: | |
238 | kfree(helper); | |
239 | return ret; | |
240 | } | |
241 | ||
242 | static int | |
243 | nfnl_cthelper_update(const struct nlattr * const tb[], | |
244 | struct nf_conntrack_helper *helper) | |
245 | { | |
246 | int ret; | |
247 | ||
248 | if (tb[NFCTH_PRIV_DATA_LEN]) | |
249 | return -EBUSY; | |
250 | ||
251 | if (tb[NFCTH_POLICY]) { | |
252 | ret = nfnl_cthelper_parse_expect_policy(helper, | |
253 | tb[NFCTH_POLICY]); | |
254 | if (ret < 0) | |
255 | return ret; | |
256 | } | |
257 | if (tb[NFCTH_QUEUE_NUM]) | |
258 | helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM])); | |
259 | ||
260 | if (tb[NFCTH_STATUS]) { | |
261 | int status = ntohl(nla_get_be32(tb[NFCTH_STATUS])); | |
262 | ||
263 | switch(status) { | |
264 | case NFCT_HELPER_STATUS_ENABLED: | |
265 | helper->flags |= NF_CT_HELPER_F_CONFIGURED; | |
266 | break; | |
267 | case NFCT_HELPER_STATUS_DISABLED: | |
268 | helper->flags &= ~NF_CT_HELPER_F_CONFIGURED; | |
269 | break; | |
270 | } | |
271 | } | |
272 | return 0; | |
273 | } | |
274 | ||
275 | static int | |
276 | nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb, | |
277 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) | |
278 | { | |
279 | const char *helper_name; | |
280 | struct nf_conntrack_helper *cur, *helper = NULL; | |
281 | struct nf_conntrack_tuple tuple; | |
282 | struct hlist_node *n; | |
283 | int ret = 0, i; | |
284 | ||
285 | if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE]) | |
286 | return -EINVAL; | |
287 | ||
288 | helper_name = nla_data(tb[NFCTH_NAME]); | |
289 | ||
290 | ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]); | |
291 | if (ret < 0) | |
292 | return ret; | |
293 | ||
294 | rcu_read_lock(); | |
295 | for (i = 0; i < nf_ct_helper_hsize && !helper; i++) { | |
296 | hlist_for_each_entry_rcu(cur, n, &nf_ct_helper_hash[i], hnode) { | |
297 | ||
298 | /* skip non-userspace conntrack helpers. */ | |
299 | if (!(cur->flags & NF_CT_HELPER_F_USERSPACE)) | |
300 | continue; | |
301 | ||
302 | if (strncmp(cur->name, helper_name, | |
303 | NF_CT_HELPER_NAME_LEN) != 0) | |
304 | continue; | |
305 | ||
306 | if ((tuple.src.l3num != cur->tuple.src.l3num || | |
307 | tuple.dst.protonum != cur->tuple.dst.protonum)) | |
308 | continue; | |
309 | ||
310 | if (nlh->nlmsg_flags & NLM_F_EXCL) { | |
311 | ret = -EEXIST; | |
312 | goto err; | |
313 | } | |
314 | helper = cur; | |
315 | break; | |
316 | } | |
317 | } | |
318 | rcu_read_unlock(); | |
319 | ||
320 | if (helper == NULL) | |
321 | ret = nfnl_cthelper_create(tb, &tuple); | |
322 | else | |
323 | ret = nfnl_cthelper_update(tb, helper); | |
324 | ||
325 | return ret; | |
326 | err: | |
327 | rcu_read_unlock(); | |
328 | return ret; | |
329 | } | |
330 | ||
331 | static int | |
332 | nfnl_cthelper_dump_tuple(struct sk_buff *skb, | |
333 | struct nf_conntrack_helper *helper) | |
334 | { | |
335 | struct nlattr *nest_parms; | |
336 | ||
337 | nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED); | |
338 | if (nest_parms == NULL) | |
339 | goto nla_put_failure; | |
340 | ||
341 | if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM, | |
342 | htons(helper->tuple.src.l3num))) | |
343 | goto nla_put_failure; | |
344 | ||
345 | if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum)) | |
346 | goto nla_put_failure; | |
347 | ||
348 | nla_nest_end(skb, nest_parms); | |
349 | return 0; | |
350 | ||
351 | nla_put_failure: | |
352 | return -1; | |
353 | } | |
354 | ||
355 | static int | |
356 | nfnl_cthelper_dump_policy(struct sk_buff *skb, | |
357 | struct nf_conntrack_helper *helper) | |
358 | { | |
359 | int i; | |
360 | struct nlattr *nest_parms1, *nest_parms2; | |
361 | ||
362 | nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED); | |
363 | if (nest_parms1 == NULL) | |
364 | goto nla_put_failure; | |
365 | ||
366 | if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM, | |
367 | htonl(helper->expect_class_max))) | |
368 | goto nla_put_failure; | |
369 | ||
370 | for (i=0; i<helper->expect_class_max; i++) { | |
371 | nest_parms2 = nla_nest_start(skb, | |
372 | (NFCTH_POLICY_SET+i) | NLA_F_NESTED); | |
373 | if (nest_parms2 == NULL) | |
374 | goto nla_put_failure; | |
375 | ||
376 | if (nla_put_string(skb, NFCTH_POLICY_NAME, | |
377 | helper->expect_policy[i].name)) | |
378 | goto nla_put_failure; | |
379 | ||
380 | if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX, | |
381 | htonl(helper->expect_policy[i].max_expected))) | |
382 | goto nla_put_failure; | |
383 | ||
384 | if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT, | |
385 | htonl(helper->expect_policy[i].timeout))) | |
386 | goto nla_put_failure; | |
387 | ||
388 | nla_nest_end(skb, nest_parms2); | |
389 | } | |
390 | nla_nest_end(skb, nest_parms1); | |
391 | return 0; | |
392 | ||
393 | nla_put_failure: | |
394 | return -1; | |
395 | } | |
396 | ||
397 | static int | |
398 | nfnl_cthelper_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type, | |
399 | int event, struct nf_conntrack_helper *helper) | |
400 | { | |
401 | struct nlmsghdr *nlh; | |
402 | struct nfgenmsg *nfmsg; | |
403 | unsigned int flags = pid ? NLM_F_MULTI : 0; | |
404 | int status; | |
405 | ||
406 | event |= NFNL_SUBSYS_CTHELPER << 8; | |
407 | nlh = nlmsg_put(skb, pid, seq, event, sizeof(*nfmsg), flags); | |
408 | if (nlh == NULL) | |
409 | goto nlmsg_failure; | |
410 | ||
411 | nfmsg = nlmsg_data(nlh); | |
412 | nfmsg->nfgen_family = AF_UNSPEC; | |
413 | nfmsg->version = NFNETLINK_V0; | |
414 | nfmsg->res_id = 0; | |
415 | ||
416 | if (nla_put_string(skb, NFCTH_NAME, helper->name)) | |
417 | goto nla_put_failure; | |
418 | ||
419 | if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num))) | |
420 | goto nla_put_failure; | |
421 | ||
422 | if (nfnl_cthelper_dump_tuple(skb, helper) < 0) | |
423 | goto nla_put_failure; | |
424 | ||
425 | if (nfnl_cthelper_dump_policy(skb, helper) < 0) | |
426 | goto nla_put_failure; | |
427 | ||
428 | if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len))) | |
429 | goto nla_put_failure; | |
430 | ||
431 | if (helper->flags & NF_CT_HELPER_F_CONFIGURED) | |
432 | status = NFCT_HELPER_STATUS_ENABLED; | |
433 | else | |
434 | status = NFCT_HELPER_STATUS_DISABLED; | |
435 | ||
436 | if (nla_put_be32(skb, NFCTH_STATUS, htonl(status))) | |
437 | goto nla_put_failure; | |
438 | ||
439 | nlmsg_end(skb, nlh); | |
440 | return skb->len; | |
441 | ||
442 | nlmsg_failure: | |
443 | nla_put_failure: | |
444 | nlmsg_cancel(skb, nlh); | |
445 | return -1; | |
446 | } | |
447 | ||
448 | static int | |
449 | nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb) | |
450 | { | |
451 | struct nf_conntrack_helper *cur, *last; | |
452 | struct hlist_node *n; | |
453 | ||
454 | rcu_read_lock(); | |
455 | last = (struct nf_conntrack_helper *)cb->args[1]; | |
456 | for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) { | |
457 | restart: | |
458 | hlist_for_each_entry_rcu(cur, n, | |
459 | &nf_ct_helper_hash[cb->args[0]], hnode) { | |
460 | ||
461 | /* skip non-userspace conntrack helpers. */ | |
462 | if (!(cur->flags & NF_CT_HELPER_F_USERSPACE)) | |
463 | continue; | |
464 | ||
465 | if (cb->args[1]) { | |
466 | if (cur != last) | |
467 | continue; | |
468 | cb->args[1] = 0; | |
469 | } | |
470 | if (nfnl_cthelper_fill_info(skb, | |
471 | NETLINK_CB(cb->skb).pid, | |
472 | cb->nlh->nlmsg_seq, | |
473 | NFNL_MSG_TYPE(cb->nlh->nlmsg_type), | |
474 | NFNL_MSG_CTHELPER_NEW, cur) < 0) { | |
475 | cb->args[1] = (unsigned long)cur; | |
476 | goto out; | |
477 | } | |
478 | } | |
479 | } | |
480 | if (cb->args[1]) { | |
481 | cb->args[1] = 0; | |
482 | goto restart; | |
483 | } | |
484 | out: | |
485 | rcu_read_unlock(); | |
486 | return skb->len; | |
487 | } | |
488 | ||
489 | static int | |
490 | nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb, | |
491 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) | |
492 | { | |
493 | int ret = -ENOENT, i; | |
494 | struct nf_conntrack_helper *cur; | |
495 | struct hlist_node *n; | |
496 | struct sk_buff *skb2; | |
497 | char *helper_name = NULL; | |
498 | struct nf_conntrack_tuple tuple; | |
499 | bool tuple_set = false; | |
500 | ||
501 | if (nlh->nlmsg_flags & NLM_F_DUMP) { | |
502 | struct netlink_dump_control c = { | |
503 | .dump = nfnl_cthelper_dump_table, | |
504 | }; | |
505 | return netlink_dump_start(nfnl, skb, nlh, &c); | |
506 | } | |
507 | ||
508 | if (tb[NFCTH_NAME]) | |
509 | helper_name = nla_data(tb[NFCTH_NAME]); | |
510 | ||
511 | if (tb[NFCTH_TUPLE]) { | |
512 | ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]); | |
513 | if (ret < 0) | |
514 | return ret; | |
515 | ||
516 | tuple_set = true; | |
517 | } | |
518 | ||
519 | for (i = 0; i < nf_ct_helper_hsize; i++) { | |
520 | hlist_for_each_entry_rcu(cur, n, &nf_ct_helper_hash[i], hnode) { | |
521 | ||
522 | /* skip non-userspace conntrack helpers. */ | |
523 | if (!(cur->flags & NF_CT_HELPER_F_USERSPACE)) | |
524 | continue; | |
525 | ||
526 | if (helper_name && strncmp(cur->name, helper_name, | |
527 | NF_CT_HELPER_NAME_LEN) != 0) { | |
528 | continue; | |
529 | } | |
530 | if (tuple_set && | |
531 | (tuple.src.l3num != cur->tuple.src.l3num || | |
532 | tuple.dst.protonum != cur->tuple.dst.protonum)) | |
533 | continue; | |
534 | ||
535 | skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); | |
536 | if (skb2 == NULL) { | |
537 | ret = -ENOMEM; | |
538 | break; | |
539 | } | |
540 | ||
541 | ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).pid, | |
542 | nlh->nlmsg_seq, | |
543 | NFNL_MSG_TYPE(nlh->nlmsg_type), | |
544 | NFNL_MSG_CTHELPER_NEW, cur); | |
545 | if (ret <= 0) { | |
546 | kfree_skb(skb2); | |
547 | break; | |
548 | } | |
549 | ||
550 | ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).pid, | |
551 | MSG_DONTWAIT); | |
552 | if (ret > 0) | |
553 | ret = 0; | |
554 | ||
555 | /* this avoids a loop in nfnetlink. */ | |
556 | return ret == -EAGAIN ? -ENOBUFS : ret; | |
557 | } | |
558 | } | |
559 | return ret; | |
560 | } | |
561 | ||
562 | static int | |
563 | nfnl_cthelper_del(struct sock *nfnl, struct sk_buff *skb, | |
564 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) | |
565 | { | |
566 | char *helper_name = NULL; | |
567 | struct nf_conntrack_helper *cur; | |
568 | struct hlist_node *n, *tmp; | |
569 | struct nf_conntrack_tuple tuple; | |
570 | bool tuple_set = false, found = false; | |
571 | int i, j = 0, ret; | |
572 | ||
573 | if (tb[NFCTH_NAME]) | |
574 | helper_name = nla_data(tb[NFCTH_NAME]); | |
575 | ||
576 | if (tb[NFCTH_TUPLE]) { | |
577 | ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]); | |
578 | if (ret < 0) | |
579 | return ret; | |
580 | ||
581 | tuple_set = true; | |
582 | } | |
583 | ||
584 | for (i = 0; i < nf_ct_helper_hsize; i++) { | |
585 | hlist_for_each_entry_safe(cur, n, tmp, &nf_ct_helper_hash[i], | |
586 | hnode) { | |
587 | /* skip non-userspace conntrack helpers. */ | |
588 | if (!(cur->flags & NF_CT_HELPER_F_USERSPACE)) | |
589 | continue; | |
590 | ||
591 | j++; | |
592 | ||
593 | if (helper_name && strncmp(cur->name, helper_name, | |
594 | NF_CT_HELPER_NAME_LEN) != 0) { | |
595 | continue; | |
596 | } | |
597 | if (tuple_set && | |
598 | (tuple.src.l3num != cur->tuple.src.l3num || | |
599 | tuple.dst.protonum != cur->tuple.dst.protonum)) | |
600 | continue; | |
601 | ||
602 | found = true; | |
603 | nf_conntrack_helper_unregister(cur); | |
604 | } | |
605 | } | |
606 | /* Make sure we return success if we flush and there is no helpers */ | |
607 | return (found || j == 0) ? 0 : -ENOENT; | |
608 | } | |
609 | ||
610 | static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = { | |
611 | [NFCTH_NAME] = { .type = NLA_NUL_STRING, | |
612 | .len = NF_CT_HELPER_NAME_LEN-1 }, | |
613 | [NFCTH_QUEUE_NUM] = { .type = NLA_U32, }, | |
614 | }; | |
615 | ||
616 | static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = { | |
617 | [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new, | |
618 | .attr_count = NFCTH_MAX, | |
619 | .policy = nfnl_cthelper_policy }, | |
620 | [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get, | |
621 | .attr_count = NFCTH_MAX, | |
622 | .policy = nfnl_cthelper_policy }, | |
623 | [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del, | |
624 | .attr_count = NFCTH_MAX, | |
625 | .policy = nfnl_cthelper_policy }, | |
626 | }; | |
627 | ||
628 | static const struct nfnetlink_subsystem nfnl_cthelper_subsys = { | |
629 | .name = "cthelper", | |
630 | .subsys_id = NFNL_SUBSYS_CTHELPER, | |
631 | .cb_count = NFNL_MSG_CTHELPER_MAX, | |
632 | .cb = nfnl_cthelper_cb, | |
633 | }; | |
634 | ||
635 | MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER); | |
636 | ||
637 | static int __init nfnl_cthelper_init(void) | |
638 | { | |
639 | int ret; | |
640 | ||
641 | ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys); | |
642 | if (ret < 0) { | |
643 | pr_err("nfnl_cthelper: cannot register with nfnetlink.\n"); | |
644 | goto err_out; | |
645 | } | |
646 | return 0; | |
647 | err_out: | |
648 | return ret; | |
649 | } | |
650 | ||
651 | static void __exit nfnl_cthelper_exit(void) | |
652 | { | |
653 | struct nf_conntrack_helper *cur; | |
654 | struct hlist_node *n, *tmp; | |
655 | int i; | |
656 | ||
657 | nfnetlink_subsys_unregister(&nfnl_cthelper_subsys); | |
658 | ||
659 | for (i=0; i<nf_ct_helper_hsize; i++) { | |
660 | hlist_for_each_entry_safe(cur, n, tmp, &nf_ct_helper_hash[i], | |
661 | hnode) { | |
662 | /* skip non-userspace conntrack helpers. */ | |
663 | if (!(cur->flags & NF_CT_HELPER_F_USERSPACE)) | |
664 | continue; | |
665 | ||
666 | nf_conntrack_helper_unregister(cur); | |
667 | } | |
668 | } | |
669 | } | |
670 | ||
671 | module_init(nfnl_cthelper_init); | |
672 | module_exit(nfnl_cthelper_exit); |