2 * (C) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
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).
8 * This software has been sponsored by Vyatta Inc. <http://www.vyatta.com>
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>
23 #include <net/netfilter/nf_conntrack_helper.h>
24 #include <net/netfilter/nf_conntrack_expect.h>
25 #include <net/netfilter/nf_conntrack_ecache.h>
27 #include <linux/netfilter/nfnetlink.h>
28 #include <linux/netfilter/nfnetlink_conntrack.h>
29 #include <linux/netfilter/nfnetlink_cthelper.h>
31 MODULE_LICENSE("GPL");
32 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
33 MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
36 nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
37 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
39 const struct nf_conn_help *help;
40 struct nf_conntrack_helper *helper;
46 /* rcu_read_lock()ed by nf_hook_slow */
47 helper = rcu_dereference(help->helper);
51 /* This is an user-space helper not yet configured, skip. */
53 (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
54 NF_CT_HELPER_F_USERSPACE)
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;
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, },
67 nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
68 const struct nlattr *attr)
70 struct nlattr *tb[NFCTH_TUPLE_MAX+1];
72 nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr, nfnl_cthelper_tuple_pol);
74 if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
77 /* Not all fields are initialized so first zero the tuple */
78 memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
80 tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
81 tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
87 nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
89 struct nf_conn_help *help = nfct_help(ct);
94 if (help->helper->data_len == 0)
97 memcpy(help->data, nla_data(attr), help->helper->data_len);
102 nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
104 const struct nf_conn_help *help = nfct_help(ct);
106 if (help->helper->data_len &&
107 nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
108 goto nla_put_failure;
116 static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
117 [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
118 .len = NF_CT_HELPER_NAME_LEN-1 },
119 [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
120 [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
124 nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
125 const struct nlattr *attr)
127 struct nlattr *tb[NFCTH_POLICY_MAX+1];
129 nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol);
131 if (!tb[NFCTH_POLICY_NAME] ||
132 !tb[NFCTH_POLICY_EXPECT_MAX] ||
133 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
136 strncpy(expect_policy->name,
137 nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
138 expect_policy->max_expected =
139 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
140 expect_policy->timeout =
141 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
146 static const struct nla_policy
147 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
148 [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
152 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
153 const struct nlattr *attr)
156 struct nf_conntrack_expect_policy *expect_policy;
157 struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
159 nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
160 nfnl_cthelper_expect_policy_set);
162 if (!tb[NFCTH_POLICY_SET_NUM])
165 helper->expect_class_max =
166 ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
168 if (helper->expect_class_max != 0 &&
169 helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
172 expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
173 helper->expect_class_max, GFP_KERNEL);
174 if (expect_policy == NULL)
177 for (i=0; i<helper->expect_class_max; i++) {
178 if (!tb[NFCTH_POLICY_SET+i])
181 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
182 tb[NFCTH_POLICY_SET+i]);
186 helper->expect_policy = expect_policy;
189 kfree(expect_policy);
194 nfnl_cthelper_create(const struct nlattr * const tb[],
195 struct nf_conntrack_tuple *tuple)
197 struct nf_conntrack_helper *helper;
200 if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
203 helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL);
207 ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
211 strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
212 helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
213 helper->flags |= NF_CT_HELPER_F_USERSPACE;
214 memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
216 helper->me = THIS_MODULE;
217 helper->help = nfnl_userspace_cthelper;
218 helper->from_nlattr = nfnl_cthelper_from_nlattr;
219 helper->to_nlattr = nfnl_cthelper_to_nlattr;
221 /* Default to queue number zero, this can be updated at any time. */
222 if (tb[NFCTH_QUEUE_NUM])
223 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
225 if (tb[NFCTH_STATUS]) {
226 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
229 case NFCT_HELPER_STATUS_ENABLED:
230 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
232 case NFCT_HELPER_STATUS_DISABLED:
233 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
238 ret = nf_conntrack_helper_register(helper);
249 nfnl_cthelper_update(const struct nlattr * const tb[],
250 struct nf_conntrack_helper *helper)
254 if (tb[NFCTH_PRIV_DATA_LEN])
257 if (tb[NFCTH_POLICY]) {
258 ret = nfnl_cthelper_parse_expect_policy(helper,
263 if (tb[NFCTH_QUEUE_NUM])
264 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
266 if (tb[NFCTH_STATUS]) {
267 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
270 case NFCT_HELPER_STATUS_ENABLED:
271 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
273 case NFCT_HELPER_STATUS_DISABLED:
274 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
282 nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb,
283 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
285 const char *helper_name;
286 struct nf_conntrack_helper *cur, *helper = NULL;
287 struct nf_conntrack_tuple tuple;
290 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
293 helper_name = nla_data(tb[NFCTH_NAME]);
295 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
300 for (i = 0; i < nf_ct_helper_hsize && !helper; i++) {
301 hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
303 /* skip non-userspace conntrack helpers. */
304 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
307 if (strncmp(cur->name, helper_name,
308 NF_CT_HELPER_NAME_LEN) != 0)
311 if ((tuple.src.l3num != cur->tuple.src.l3num ||
312 tuple.dst.protonum != cur->tuple.dst.protonum))
315 if (nlh->nlmsg_flags & NLM_F_EXCL) {
326 ret = nfnl_cthelper_create(tb, &tuple);
328 ret = nfnl_cthelper_update(tb, helper);
337 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
338 struct nf_conntrack_helper *helper)
340 struct nlattr *nest_parms;
342 nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
343 if (nest_parms == NULL)
344 goto nla_put_failure;
346 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
347 htons(helper->tuple.src.l3num)))
348 goto nla_put_failure;
350 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
351 goto nla_put_failure;
353 nla_nest_end(skb, nest_parms);
361 nfnl_cthelper_dump_policy(struct sk_buff *skb,
362 struct nf_conntrack_helper *helper)
365 struct nlattr *nest_parms1, *nest_parms2;
367 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
368 if (nest_parms1 == NULL)
369 goto nla_put_failure;
371 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
372 htonl(helper->expect_class_max)))
373 goto nla_put_failure;
375 for (i=0; i<helper->expect_class_max; i++) {
376 nest_parms2 = nla_nest_start(skb,
377 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
378 if (nest_parms2 == NULL)
379 goto nla_put_failure;
381 if (nla_put_string(skb, NFCTH_POLICY_NAME,
382 helper->expect_policy[i].name))
383 goto nla_put_failure;
385 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
386 htonl(helper->expect_policy[i].max_expected)))
387 goto nla_put_failure;
389 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
390 htonl(helper->expect_policy[i].timeout)))
391 goto nla_put_failure;
393 nla_nest_end(skb, nest_parms2);
395 nla_nest_end(skb, nest_parms1);
403 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
404 int event, struct nf_conntrack_helper *helper)
406 struct nlmsghdr *nlh;
407 struct nfgenmsg *nfmsg;
408 unsigned int flags = portid ? NLM_F_MULTI : 0;
411 event |= NFNL_SUBSYS_CTHELPER << 8;
412 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
416 nfmsg = nlmsg_data(nlh);
417 nfmsg->nfgen_family = AF_UNSPEC;
418 nfmsg->version = NFNETLINK_V0;
421 if (nla_put_string(skb, NFCTH_NAME, helper->name))
422 goto nla_put_failure;
424 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
425 goto nla_put_failure;
427 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
428 goto nla_put_failure;
430 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
431 goto nla_put_failure;
433 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
434 goto nla_put_failure;
436 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
437 status = NFCT_HELPER_STATUS_ENABLED;
439 status = NFCT_HELPER_STATUS_DISABLED;
441 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
442 goto nla_put_failure;
449 nlmsg_cancel(skb, nlh);
454 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
456 struct nf_conntrack_helper *cur, *last;
459 last = (struct nf_conntrack_helper *)cb->args[1];
460 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
462 hlist_for_each_entry_rcu(cur,
463 &nf_ct_helper_hash[cb->args[0]], hnode) {
465 /* skip non-userspace conntrack helpers. */
466 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
474 if (nfnl_cthelper_fill_info(skb,
475 NETLINK_CB(cb->skb).portid,
477 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
478 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
479 cb->args[1] = (unsigned long)cur;
494 nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb,
495 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
497 int ret = -ENOENT, i;
498 struct nf_conntrack_helper *cur;
499 struct sk_buff *skb2;
500 char *helper_name = NULL;
501 struct nf_conntrack_tuple tuple;
502 bool tuple_set = false;
504 if (nlh->nlmsg_flags & NLM_F_DUMP) {
505 struct netlink_dump_control c = {
506 .dump = nfnl_cthelper_dump_table,
508 return netlink_dump_start(nfnl, skb, nlh, &c);
512 helper_name = nla_data(tb[NFCTH_NAME]);
514 if (tb[NFCTH_TUPLE]) {
515 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
522 for (i = 0; i < nf_ct_helper_hsize; i++) {
523 hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
525 /* skip non-userspace conntrack helpers. */
526 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
529 if (helper_name && strncmp(cur->name, helper_name,
530 NF_CT_HELPER_NAME_LEN) != 0) {
534 (tuple.src.l3num != cur->tuple.src.l3num ||
535 tuple.dst.protonum != cur->tuple.dst.protonum))
538 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
544 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
546 NFNL_MSG_TYPE(nlh->nlmsg_type),
547 NFNL_MSG_CTHELPER_NEW, cur);
553 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
558 /* this avoids a loop in nfnetlink. */
559 return ret == -EAGAIN ? -ENOBUFS : ret;
566 nfnl_cthelper_del(struct sock *nfnl, struct sk_buff *skb,
567 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
569 char *helper_name = NULL;
570 struct nf_conntrack_helper *cur;
571 struct hlist_node *tmp;
572 struct nf_conntrack_tuple tuple;
573 bool tuple_set = false, found = false;
577 helper_name = nla_data(tb[NFCTH_NAME]);
579 if (tb[NFCTH_TUPLE]) {
580 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
587 for (i = 0; i < nf_ct_helper_hsize; i++) {
588 hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
590 /* skip non-userspace conntrack helpers. */
591 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
596 if (helper_name && strncmp(cur->name, helper_name,
597 NF_CT_HELPER_NAME_LEN) != 0) {
601 (tuple.src.l3num != cur->tuple.src.l3num ||
602 tuple.dst.protonum != cur->tuple.dst.protonum))
606 nf_conntrack_helper_unregister(cur);
609 /* Make sure we return success if we flush and there is no helpers */
610 return (found || j == 0) ? 0 : -ENOENT;
613 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
614 [NFCTH_NAME] = { .type = NLA_NUL_STRING,
615 .len = NF_CT_HELPER_NAME_LEN-1 },
616 [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
619 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
620 [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
621 .attr_count = NFCTH_MAX,
622 .policy = nfnl_cthelper_policy },
623 [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
624 .attr_count = NFCTH_MAX,
625 .policy = nfnl_cthelper_policy },
626 [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
627 .attr_count = NFCTH_MAX,
628 .policy = nfnl_cthelper_policy },
631 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
633 .subsys_id = NFNL_SUBSYS_CTHELPER,
634 .cb_count = NFNL_MSG_CTHELPER_MAX,
635 .cb = nfnl_cthelper_cb,
638 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
640 static int __init nfnl_cthelper_init(void)
644 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
646 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
654 static void __exit nfnl_cthelper_exit(void)
656 struct nf_conntrack_helper *cur;
657 struct hlist_node *tmp;
660 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
662 for (i=0; i<nf_ct_helper_hsize; i++) {
663 hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
665 /* skip non-userspace conntrack helpers. */
666 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
669 nf_conntrack_helper_unregister(cur);
674 module_init(nfnl_cthelper_init);
675 module_exit(nfnl_cthelper_exit);