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 <linux/capability.h>
21 #include <net/netlink.h>
24 #include <net/netfilter/nf_conntrack_helper.h>
25 #include <net/netfilter/nf_conntrack_expect.h>
26 #include <net/netfilter/nf_conntrack_ecache.h>
28 #include <linux/netfilter/nfnetlink.h>
29 #include <linux/netfilter/nfnetlink_conntrack.h>
30 #include <linux/netfilter/nfnetlink_cthelper.h>
32 MODULE_LICENSE("GPL");
33 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
34 MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
36 struct nfnl_cthelper {
37 struct list_head list;
38 struct nf_conntrack_helper helper;
41 static LIST_HEAD(nfnl_cthelper_list);
44 nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
45 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
47 const struct nf_conn_help *help;
48 struct nf_conntrack_helper *helper;
54 /* rcu_read_lock()ed by nf_hook_thresh */
55 helper = rcu_dereference(help->helper);
59 /* This is a user-space helper not yet configured, skip. */
61 (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
62 NF_CT_HELPER_F_USERSPACE)
65 /* If the user-space helper is not available, don't block traffic. */
66 return NF_QUEUE_NR(helper->queue_num) | NF_VERDICT_FLAG_QUEUE_BYPASS;
69 static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
70 [NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
71 [NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
75 nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
76 const struct nlattr *attr)
79 struct nlattr *tb[NFCTH_TUPLE_MAX+1];
81 err = nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr,
82 nfnl_cthelper_tuple_pol, NULL);
86 if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
89 /* Not all fields are initialized so first zero the tuple */
90 memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
92 tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
93 tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
99 nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
101 struct nf_conn_help *help = nfct_help(ct);
106 if (help->helper->data_len == 0)
109 nla_memcpy(help->data, nla_data(attr), sizeof(help->data));
114 nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
116 const struct nf_conn_help *help = nfct_help(ct);
118 if (help->helper->data_len &&
119 nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
120 goto nla_put_failure;
128 static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
129 [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
130 .len = NF_CT_HELPER_NAME_LEN-1 },
131 [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
132 [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
136 nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
137 const struct nlattr *attr)
140 struct nlattr *tb[NFCTH_POLICY_MAX+1];
142 err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr,
143 nfnl_cthelper_expect_pol, NULL);
147 if (!tb[NFCTH_POLICY_NAME] ||
148 !tb[NFCTH_POLICY_EXPECT_MAX] ||
149 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
152 strncpy(expect_policy->name,
153 nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
154 expect_policy->max_expected =
155 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
156 if (expect_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
159 expect_policy->timeout =
160 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
165 static const struct nla_policy
166 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
167 [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
171 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
172 const struct nlattr *attr)
175 struct nf_conntrack_expect_policy *expect_policy;
176 struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
177 unsigned int class_max;
179 ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
180 nfnl_cthelper_expect_policy_set, NULL);
184 if (!tb[NFCTH_POLICY_SET_NUM])
187 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
190 if (class_max > NF_CT_MAX_EXPECT_CLASSES)
193 expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
194 class_max, GFP_KERNEL);
195 if (expect_policy == NULL)
198 for (i = 0; i < class_max; i++) {
199 if (!tb[NFCTH_POLICY_SET+i])
202 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
203 tb[NFCTH_POLICY_SET+i]);
208 helper->expect_class_max = class_max - 1;
209 helper->expect_policy = expect_policy;
212 kfree(expect_policy);
217 nfnl_cthelper_create(const struct nlattr * const tb[],
218 struct nf_conntrack_tuple *tuple)
220 struct nf_conntrack_helper *helper;
221 struct nfnl_cthelper *nfcth;
225 if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
228 nfcth = kzalloc(sizeof(*nfcth), GFP_KERNEL);
231 helper = &nfcth->helper;
233 ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
237 strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
238 size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
239 if (size > FIELD_SIZEOF(struct nf_conn_help, data)) {
244 helper->flags |= NF_CT_HELPER_F_USERSPACE;
245 memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
247 helper->me = THIS_MODULE;
248 helper->help = nfnl_userspace_cthelper;
249 helper->from_nlattr = nfnl_cthelper_from_nlattr;
250 helper->to_nlattr = nfnl_cthelper_to_nlattr;
252 /* Default to queue number zero, this can be updated at any time. */
253 if (tb[NFCTH_QUEUE_NUM])
254 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
256 if (tb[NFCTH_STATUS]) {
257 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
260 case NFCT_HELPER_STATUS_ENABLED:
261 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
263 case NFCT_HELPER_STATUS_DISABLED:
264 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
269 ret = nf_conntrack_helper_register(helper);
273 list_add_tail(&nfcth->list, &nfnl_cthelper_list);
276 kfree(helper->expect_policy);
283 nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy,
284 struct nf_conntrack_expect_policy *new_policy,
285 const struct nlattr *attr)
287 struct nlattr *tb[NFCTH_POLICY_MAX + 1];
290 err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr,
291 nfnl_cthelper_expect_pol, NULL);
295 if (!tb[NFCTH_POLICY_NAME] ||
296 !tb[NFCTH_POLICY_EXPECT_MAX] ||
297 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
300 if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name))
303 new_policy->max_expected =
304 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
305 if (new_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
308 new_policy->timeout =
309 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
314 static int nfnl_cthelper_update_policy_all(struct nlattr *tb[],
315 struct nf_conntrack_helper *helper)
317 struct nf_conntrack_expect_policy *new_policy;
318 struct nf_conntrack_expect_policy *policy;
321 new_policy = kmalloc_array(helper->expect_class_max + 1,
322 sizeof(*new_policy), GFP_KERNEL);
326 /* Check first that all policy attributes are well-formed, so we don't
327 * leave things in inconsistent state on errors.
329 for (i = 0; i < helper->expect_class_max + 1; i++) {
331 if (!tb[NFCTH_POLICY_SET + i]) {
336 ret = nfnl_cthelper_update_policy_one(&helper->expect_policy[i],
338 tb[NFCTH_POLICY_SET + i]);
342 /* Now we can safely update them. */
343 for (i = 0; i < helper->expect_class_max + 1; i++) {
344 policy = (struct nf_conntrack_expect_policy *)
345 &helper->expect_policy[i];
346 policy->max_expected = new_policy->max_expected;
347 policy->timeout = new_policy->timeout;
355 static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper,
356 const struct nlattr *attr)
358 struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1];
359 unsigned int class_max;
362 err = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
363 nfnl_cthelper_expect_policy_set, NULL);
367 if (!tb[NFCTH_POLICY_SET_NUM])
370 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
371 if (helper->expect_class_max + 1 != class_max)
374 return nfnl_cthelper_update_policy_all(tb, helper);
378 nfnl_cthelper_update(const struct nlattr * const tb[],
379 struct nf_conntrack_helper *helper)
383 if (tb[NFCTH_PRIV_DATA_LEN])
386 if (tb[NFCTH_POLICY]) {
387 ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
391 if (tb[NFCTH_QUEUE_NUM])
392 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
394 if (tb[NFCTH_STATUS]) {
395 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
398 case NFCT_HELPER_STATUS_ENABLED:
399 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
401 case NFCT_HELPER_STATUS_DISABLED:
402 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
409 static int nfnl_cthelper_new(struct net *net, struct sock *nfnl,
410 struct sk_buff *skb, const struct nlmsghdr *nlh,
411 const struct nlattr * const tb[],
412 struct netlink_ext_ack *extack)
414 const char *helper_name;
415 struct nf_conntrack_helper *cur, *helper = NULL;
416 struct nf_conntrack_tuple tuple;
417 struct nfnl_cthelper *nlcth;
420 if (!capable(CAP_NET_ADMIN))
423 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
426 helper_name = nla_data(tb[NFCTH_NAME]);
428 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
432 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
433 cur = &nlcth->helper;
435 if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
438 if ((tuple.src.l3num != cur->tuple.src.l3num ||
439 tuple.dst.protonum != cur->tuple.dst.protonum))
442 if (nlh->nlmsg_flags & NLM_F_EXCL)
450 ret = nfnl_cthelper_create(tb, &tuple);
452 ret = nfnl_cthelper_update(tb, helper);
458 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
459 struct nf_conntrack_helper *helper)
461 struct nlattr *nest_parms;
463 nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
464 if (nest_parms == NULL)
465 goto nla_put_failure;
467 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
468 htons(helper->tuple.src.l3num)))
469 goto nla_put_failure;
471 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
472 goto nla_put_failure;
474 nla_nest_end(skb, nest_parms);
482 nfnl_cthelper_dump_policy(struct sk_buff *skb,
483 struct nf_conntrack_helper *helper)
486 struct nlattr *nest_parms1, *nest_parms2;
488 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
489 if (nest_parms1 == NULL)
490 goto nla_put_failure;
492 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
493 htonl(helper->expect_class_max + 1)))
494 goto nla_put_failure;
496 for (i = 0; i < helper->expect_class_max + 1; i++) {
497 nest_parms2 = nla_nest_start(skb,
498 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
499 if (nest_parms2 == NULL)
500 goto nla_put_failure;
502 if (nla_put_string(skb, NFCTH_POLICY_NAME,
503 helper->expect_policy[i].name))
504 goto nla_put_failure;
506 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
507 htonl(helper->expect_policy[i].max_expected)))
508 goto nla_put_failure;
510 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
511 htonl(helper->expect_policy[i].timeout)))
512 goto nla_put_failure;
514 nla_nest_end(skb, nest_parms2);
516 nla_nest_end(skb, nest_parms1);
524 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
525 int event, struct nf_conntrack_helper *helper)
527 struct nlmsghdr *nlh;
528 struct nfgenmsg *nfmsg;
529 unsigned int flags = portid ? NLM_F_MULTI : 0;
532 event = nfnl_msg_type(NFNL_SUBSYS_CTHELPER, event);
533 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
537 nfmsg = nlmsg_data(nlh);
538 nfmsg->nfgen_family = AF_UNSPEC;
539 nfmsg->version = NFNETLINK_V0;
542 if (nla_put_string(skb, NFCTH_NAME, helper->name))
543 goto nla_put_failure;
545 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
546 goto nla_put_failure;
548 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
549 goto nla_put_failure;
551 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
552 goto nla_put_failure;
554 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
555 goto nla_put_failure;
557 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
558 status = NFCT_HELPER_STATUS_ENABLED;
560 status = NFCT_HELPER_STATUS_DISABLED;
562 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
563 goto nla_put_failure;
570 nlmsg_cancel(skb, nlh);
575 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
577 struct nf_conntrack_helper *cur, *last;
580 last = (struct nf_conntrack_helper *)cb->args[1];
581 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
583 hlist_for_each_entry_rcu(cur,
584 &nf_ct_helper_hash[cb->args[0]], hnode) {
586 /* skip non-userspace conntrack helpers. */
587 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
595 if (nfnl_cthelper_fill_info(skb,
596 NETLINK_CB(cb->skb).portid,
598 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
599 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
600 cb->args[1] = (unsigned long)cur;
614 static int nfnl_cthelper_get(struct net *net, struct sock *nfnl,
615 struct sk_buff *skb, const struct nlmsghdr *nlh,
616 const struct nlattr * const tb[],
617 struct netlink_ext_ack *extack)
620 struct nf_conntrack_helper *cur;
621 struct sk_buff *skb2;
622 char *helper_name = NULL;
623 struct nf_conntrack_tuple tuple;
624 struct nfnl_cthelper *nlcth;
625 bool tuple_set = false;
627 if (!capable(CAP_NET_ADMIN))
630 if (nlh->nlmsg_flags & NLM_F_DUMP) {
631 struct netlink_dump_control c = {
632 .dump = nfnl_cthelper_dump_table,
634 return netlink_dump_start(nfnl, skb, nlh, &c);
638 helper_name = nla_data(tb[NFCTH_NAME]);
640 if (tb[NFCTH_TUPLE]) {
641 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
648 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
649 cur = &nlcth->helper;
651 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
655 (tuple.src.l3num != cur->tuple.src.l3num ||
656 tuple.dst.protonum != cur->tuple.dst.protonum))
659 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
665 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
667 NFNL_MSG_TYPE(nlh->nlmsg_type),
668 NFNL_MSG_CTHELPER_NEW, cur);
674 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
679 /* this avoids a loop in nfnetlink. */
680 return ret == -EAGAIN ? -ENOBUFS : ret;
685 static int nfnl_cthelper_del(struct net *net, struct sock *nfnl,
686 struct sk_buff *skb, const struct nlmsghdr *nlh,
687 const struct nlattr * const tb[],
688 struct netlink_ext_ack *extack)
690 char *helper_name = NULL;
691 struct nf_conntrack_helper *cur;
692 struct nf_conntrack_tuple tuple;
693 bool tuple_set = false, found = false;
694 struct nfnl_cthelper *nlcth, *n;
697 if (!capable(CAP_NET_ADMIN))
701 helper_name = nla_data(tb[NFCTH_NAME]);
703 if (tb[NFCTH_TUPLE]) {
704 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
712 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
713 cur = &nlcth->helper;
717 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
721 (tuple.src.l3num != cur->tuple.src.l3num ||
722 tuple.dst.protonum != cur->tuple.dst.protonum))
725 if (refcount_dec_if_one(&cur->refcnt)) {
727 nf_conntrack_helper_unregister(cur);
728 kfree(cur->expect_policy);
730 list_del(&nlcth->list);
737 /* Make sure we return success if we flush and there is no helpers */
738 return (found || j == 0) ? 0 : ret;
741 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
742 [NFCTH_NAME] = { .type = NLA_NUL_STRING,
743 .len = NF_CT_HELPER_NAME_LEN-1 },
744 [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
747 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
748 [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
749 .attr_count = NFCTH_MAX,
750 .policy = nfnl_cthelper_policy },
751 [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
752 .attr_count = NFCTH_MAX,
753 .policy = nfnl_cthelper_policy },
754 [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
755 .attr_count = NFCTH_MAX,
756 .policy = nfnl_cthelper_policy },
759 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
761 .subsys_id = NFNL_SUBSYS_CTHELPER,
762 .cb_count = NFNL_MSG_CTHELPER_MAX,
763 .cb = nfnl_cthelper_cb,
766 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
768 static int __init nfnl_cthelper_init(void)
772 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
774 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
782 static void __exit nfnl_cthelper_exit(void)
784 struct nf_conntrack_helper *cur;
785 struct nfnl_cthelper *nlcth, *n;
787 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
789 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
790 cur = &nlcth->helper;
792 nf_conntrack_helper_unregister(cur);
793 kfree(cur->expect_policy);
798 module_init(nfnl_cthelper_init);
799 module_exit(nfnl_cthelper_exit);