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)
71 struct nlattr *tb[NFCTH_TUPLE_MAX+1];
73 err = nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr, nfnl_cthelper_tuple_pol);
77 if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
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 const 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)
128 struct nlattr *tb[NFCTH_POLICY_MAX+1];
130 err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol);
134 if (!tb[NFCTH_POLICY_NAME] ||
135 !tb[NFCTH_POLICY_EXPECT_MAX] ||
136 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
139 strncpy(expect_policy->name,
140 nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
141 expect_policy->max_expected =
142 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
143 expect_policy->timeout =
144 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
149 static const struct nla_policy
150 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
151 [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
155 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
156 const struct nlattr *attr)
159 struct nf_conntrack_expect_policy *expect_policy;
160 struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
162 ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
163 nfnl_cthelper_expect_policy_set);
167 if (!tb[NFCTH_POLICY_SET_NUM])
170 helper->expect_class_max =
171 ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
173 if (helper->expect_class_max != 0 &&
174 helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
177 expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
178 helper->expect_class_max, GFP_KERNEL);
179 if (expect_policy == NULL)
182 for (i=0; i<helper->expect_class_max; i++) {
183 if (!tb[NFCTH_POLICY_SET+i])
186 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
187 tb[NFCTH_POLICY_SET+i]);
191 helper->expect_policy = expect_policy;
194 kfree(expect_policy);
199 nfnl_cthelper_create(const struct nlattr * const tb[],
200 struct nf_conntrack_tuple *tuple)
202 struct nf_conntrack_helper *helper;
205 if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
208 helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL);
212 ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
216 strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
217 helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
218 helper->flags |= NF_CT_HELPER_F_USERSPACE;
219 memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
221 helper->me = THIS_MODULE;
222 helper->help = nfnl_userspace_cthelper;
223 helper->from_nlattr = nfnl_cthelper_from_nlattr;
224 helper->to_nlattr = nfnl_cthelper_to_nlattr;
226 /* Default to queue number zero, this can be updated at any time. */
227 if (tb[NFCTH_QUEUE_NUM])
228 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
230 if (tb[NFCTH_STATUS]) {
231 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
234 case NFCT_HELPER_STATUS_ENABLED:
235 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
237 case NFCT_HELPER_STATUS_DISABLED:
238 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
243 ret = nf_conntrack_helper_register(helper);
254 nfnl_cthelper_update(const struct nlattr * const tb[],
255 struct nf_conntrack_helper *helper)
259 if (tb[NFCTH_PRIV_DATA_LEN])
262 if (tb[NFCTH_POLICY]) {
263 ret = nfnl_cthelper_parse_expect_policy(helper,
268 if (tb[NFCTH_QUEUE_NUM])
269 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
271 if (tb[NFCTH_STATUS]) {
272 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
275 case NFCT_HELPER_STATUS_ENABLED:
276 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
278 case NFCT_HELPER_STATUS_DISABLED:
279 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
287 nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb,
288 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
290 const char *helper_name;
291 struct nf_conntrack_helper *cur, *helper = NULL;
292 struct nf_conntrack_tuple tuple;
295 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
298 helper_name = nla_data(tb[NFCTH_NAME]);
300 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
305 for (i = 0; i < nf_ct_helper_hsize && !helper; i++) {
306 hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
308 /* skip non-userspace conntrack helpers. */
309 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
312 if (strncmp(cur->name, helper_name,
313 NF_CT_HELPER_NAME_LEN) != 0)
316 if ((tuple.src.l3num != cur->tuple.src.l3num ||
317 tuple.dst.protonum != cur->tuple.dst.protonum))
320 if (nlh->nlmsg_flags & NLM_F_EXCL) {
331 ret = nfnl_cthelper_create(tb, &tuple);
333 ret = nfnl_cthelper_update(tb, helper);
342 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
343 struct nf_conntrack_helper *helper)
345 struct nlattr *nest_parms;
347 nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
348 if (nest_parms == NULL)
349 goto nla_put_failure;
351 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
352 htons(helper->tuple.src.l3num)))
353 goto nla_put_failure;
355 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
356 goto nla_put_failure;
358 nla_nest_end(skb, nest_parms);
366 nfnl_cthelper_dump_policy(struct sk_buff *skb,
367 struct nf_conntrack_helper *helper)
370 struct nlattr *nest_parms1, *nest_parms2;
372 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
373 if (nest_parms1 == NULL)
374 goto nla_put_failure;
376 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
377 htonl(helper->expect_class_max)))
378 goto nla_put_failure;
380 for (i=0; i<helper->expect_class_max; i++) {
381 nest_parms2 = nla_nest_start(skb,
382 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
383 if (nest_parms2 == NULL)
384 goto nla_put_failure;
386 if (nla_put_string(skb, NFCTH_POLICY_NAME,
387 helper->expect_policy[i].name))
388 goto nla_put_failure;
390 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
391 htonl(helper->expect_policy[i].max_expected)))
392 goto nla_put_failure;
394 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
395 htonl(helper->expect_policy[i].timeout)))
396 goto nla_put_failure;
398 nla_nest_end(skb, nest_parms2);
400 nla_nest_end(skb, nest_parms1);
408 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
409 int event, struct nf_conntrack_helper *helper)
411 struct nlmsghdr *nlh;
412 struct nfgenmsg *nfmsg;
413 unsigned int flags = portid ? NLM_F_MULTI : 0;
416 event |= NFNL_SUBSYS_CTHELPER << 8;
417 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
421 nfmsg = nlmsg_data(nlh);
422 nfmsg->nfgen_family = AF_UNSPEC;
423 nfmsg->version = NFNETLINK_V0;
426 if (nla_put_string(skb, NFCTH_NAME, helper->name))
427 goto nla_put_failure;
429 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
430 goto nla_put_failure;
432 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
433 goto nla_put_failure;
435 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
436 goto nla_put_failure;
438 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
439 goto nla_put_failure;
441 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
442 status = NFCT_HELPER_STATUS_ENABLED;
444 status = NFCT_HELPER_STATUS_DISABLED;
446 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
447 goto nla_put_failure;
454 nlmsg_cancel(skb, nlh);
459 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
461 struct nf_conntrack_helper *cur, *last;
464 last = (struct nf_conntrack_helper *)cb->args[1];
465 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
467 hlist_for_each_entry_rcu(cur,
468 &nf_ct_helper_hash[cb->args[0]], hnode) {
470 /* skip non-userspace conntrack helpers. */
471 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
479 if (nfnl_cthelper_fill_info(skb,
480 NETLINK_CB(cb->skb).portid,
482 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
483 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
484 cb->args[1] = (unsigned long)cur;
499 nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb,
500 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
502 int ret = -ENOENT, i;
503 struct nf_conntrack_helper *cur;
504 struct sk_buff *skb2;
505 char *helper_name = NULL;
506 struct nf_conntrack_tuple tuple;
507 bool tuple_set = false;
509 if (nlh->nlmsg_flags & NLM_F_DUMP) {
510 struct netlink_dump_control c = {
511 .dump = nfnl_cthelper_dump_table,
513 return netlink_dump_start(nfnl, skb, nlh, &c);
517 helper_name = nla_data(tb[NFCTH_NAME]);
519 if (tb[NFCTH_TUPLE]) {
520 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
527 for (i = 0; i < nf_ct_helper_hsize; i++) {
528 hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
530 /* skip non-userspace conntrack helpers. */
531 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
534 if (helper_name && strncmp(cur->name, helper_name,
535 NF_CT_HELPER_NAME_LEN) != 0) {
539 (tuple.src.l3num != cur->tuple.src.l3num ||
540 tuple.dst.protonum != cur->tuple.dst.protonum))
543 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
549 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
551 NFNL_MSG_TYPE(nlh->nlmsg_type),
552 NFNL_MSG_CTHELPER_NEW, cur);
558 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
563 /* this avoids a loop in nfnetlink. */
564 return ret == -EAGAIN ? -ENOBUFS : ret;
571 nfnl_cthelper_del(struct sock *nfnl, struct sk_buff *skb,
572 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
574 char *helper_name = NULL;
575 struct nf_conntrack_helper *cur;
576 struct hlist_node *tmp;
577 struct nf_conntrack_tuple tuple;
578 bool tuple_set = false, found = false;
582 helper_name = nla_data(tb[NFCTH_NAME]);
584 if (tb[NFCTH_TUPLE]) {
585 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
592 for (i = 0; i < nf_ct_helper_hsize; i++) {
593 hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
595 /* skip non-userspace conntrack helpers. */
596 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
601 if (helper_name && strncmp(cur->name, helper_name,
602 NF_CT_HELPER_NAME_LEN) != 0) {
606 (tuple.src.l3num != cur->tuple.src.l3num ||
607 tuple.dst.protonum != cur->tuple.dst.protonum))
611 nf_conntrack_helper_unregister(cur);
614 /* Make sure we return success if we flush and there is no helpers */
615 return (found || j == 0) ? 0 : -ENOENT;
618 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
619 [NFCTH_NAME] = { .type = NLA_NUL_STRING,
620 .len = NF_CT_HELPER_NAME_LEN-1 },
621 [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
624 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
625 [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
626 .attr_count = NFCTH_MAX,
627 .policy = nfnl_cthelper_policy },
628 [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
629 .attr_count = NFCTH_MAX,
630 .policy = nfnl_cthelper_policy },
631 [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
632 .attr_count = NFCTH_MAX,
633 .policy = nfnl_cthelper_policy },
636 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
638 .subsys_id = NFNL_SUBSYS_CTHELPER,
639 .cb_count = NFNL_MSG_CTHELPER_MAX,
640 .cb = nfnl_cthelper_cb,
643 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
645 static int __init nfnl_cthelper_init(void)
649 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
651 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
659 static void __exit nfnl_cthelper_exit(void)
661 struct nf_conntrack_helper *cur;
662 struct hlist_node *tmp;
665 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
667 for (i=0; i<nf_ct_helper_hsize; i++) {
668 hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
670 /* skip non-userspace conntrack helpers. */
671 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
674 nf_conntrack_helper_unregister(cur);
679 module_init(nfnl_cthelper_init);
680 module_exit(nfnl_cthelper_exit);