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, 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 nla_strlcpy(expect_policy->name,
153 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 = kcalloc(class_max,
194 sizeof(struct nf_conntrack_expect_policy),
196 if (expect_policy == NULL)
199 for (i = 0; i < class_max; i++) {
200 if (!tb[NFCTH_POLICY_SET+i])
203 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
204 tb[NFCTH_POLICY_SET+i]);
209 helper->expect_class_max = class_max - 1;
210 helper->expect_policy = expect_policy;
213 kfree(expect_policy);
218 nfnl_cthelper_create(const struct nlattr * const tb[],
219 struct nf_conntrack_tuple *tuple)
221 struct nf_conntrack_helper *helper;
222 struct nfnl_cthelper *nfcth;
226 if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
229 nfcth = kzalloc(sizeof(*nfcth), GFP_KERNEL);
232 helper = &nfcth->helper;
234 ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
238 nla_strlcpy(helper->name,
239 tb[NFCTH_NAME], NF_CT_HELPER_NAME_LEN);
240 size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
241 if (size > FIELD_SIZEOF(struct nf_conn_help, data)) {
245 helper->data_len = size;
247 helper->flags |= NF_CT_HELPER_F_USERSPACE;
248 memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
250 helper->me = THIS_MODULE;
251 helper->help = nfnl_userspace_cthelper;
252 helper->from_nlattr = nfnl_cthelper_from_nlattr;
253 helper->to_nlattr = nfnl_cthelper_to_nlattr;
255 /* Default to queue number zero, this can be updated at any time. */
256 if (tb[NFCTH_QUEUE_NUM])
257 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
259 if (tb[NFCTH_STATUS]) {
260 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
263 case NFCT_HELPER_STATUS_ENABLED:
264 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
266 case NFCT_HELPER_STATUS_DISABLED:
267 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
272 ret = nf_conntrack_helper_register(helper);
276 list_add_tail(&nfcth->list, &nfnl_cthelper_list);
279 kfree(helper->expect_policy);
286 nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy,
287 struct nf_conntrack_expect_policy *new_policy,
288 const struct nlattr *attr)
290 struct nlattr *tb[NFCTH_POLICY_MAX + 1];
293 err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr,
294 nfnl_cthelper_expect_pol, NULL);
298 if (!tb[NFCTH_POLICY_NAME] ||
299 !tb[NFCTH_POLICY_EXPECT_MAX] ||
300 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
303 if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name))
306 new_policy->max_expected =
307 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
308 if (new_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
311 new_policy->timeout =
312 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
317 static int nfnl_cthelper_update_policy_all(struct nlattr *tb[],
318 struct nf_conntrack_helper *helper)
320 struct nf_conntrack_expect_policy *new_policy;
321 struct nf_conntrack_expect_policy *policy;
324 new_policy = kmalloc_array(helper->expect_class_max + 1,
325 sizeof(*new_policy), GFP_KERNEL);
329 /* Check first that all policy attributes are well-formed, so we don't
330 * leave things in inconsistent state on errors.
332 for (i = 0; i < helper->expect_class_max + 1; i++) {
334 if (!tb[NFCTH_POLICY_SET + i]) {
339 ret = nfnl_cthelper_update_policy_one(&helper->expect_policy[i],
341 tb[NFCTH_POLICY_SET + i]);
345 /* Now we can safely update them. */
346 for (i = 0; i < helper->expect_class_max + 1; i++) {
347 policy = (struct nf_conntrack_expect_policy *)
348 &helper->expect_policy[i];
349 policy->max_expected = new_policy->max_expected;
350 policy->timeout = new_policy->timeout;
358 static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper,
359 const struct nlattr *attr)
361 struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1];
362 unsigned int class_max;
365 err = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
366 nfnl_cthelper_expect_policy_set, NULL);
370 if (!tb[NFCTH_POLICY_SET_NUM])
373 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
374 if (helper->expect_class_max + 1 != class_max)
377 return nfnl_cthelper_update_policy_all(tb, helper);
381 nfnl_cthelper_update(const struct nlattr * const tb[],
382 struct nf_conntrack_helper *helper)
387 if (tb[NFCTH_PRIV_DATA_LEN]) {
388 size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
389 if (size != helper->data_len)
393 if (tb[NFCTH_POLICY]) {
394 ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
398 if (tb[NFCTH_QUEUE_NUM])
399 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
401 if (tb[NFCTH_STATUS]) {
402 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
405 case NFCT_HELPER_STATUS_ENABLED:
406 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
408 case NFCT_HELPER_STATUS_DISABLED:
409 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
416 static int nfnl_cthelper_new(struct net *net, struct sock *nfnl,
417 struct sk_buff *skb, const struct nlmsghdr *nlh,
418 const struct nlattr * const tb[],
419 struct netlink_ext_ack *extack)
421 const char *helper_name;
422 struct nf_conntrack_helper *cur, *helper = NULL;
423 struct nf_conntrack_tuple tuple;
424 struct nfnl_cthelper *nlcth;
427 if (!capable(CAP_NET_ADMIN))
430 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
433 helper_name = nla_data(tb[NFCTH_NAME]);
435 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
439 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
440 cur = &nlcth->helper;
442 if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
445 if ((tuple.src.l3num != cur->tuple.src.l3num ||
446 tuple.dst.protonum != cur->tuple.dst.protonum))
449 if (nlh->nlmsg_flags & NLM_F_EXCL)
457 ret = nfnl_cthelper_create(tb, &tuple);
459 ret = nfnl_cthelper_update(tb, helper);
465 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
466 struct nf_conntrack_helper *helper)
468 struct nlattr *nest_parms;
470 nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
471 if (nest_parms == NULL)
472 goto nla_put_failure;
474 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
475 htons(helper->tuple.src.l3num)))
476 goto nla_put_failure;
478 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
479 goto nla_put_failure;
481 nla_nest_end(skb, nest_parms);
489 nfnl_cthelper_dump_policy(struct sk_buff *skb,
490 struct nf_conntrack_helper *helper)
493 struct nlattr *nest_parms1, *nest_parms2;
495 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
496 if (nest_parms1 == NULL)
497 goto nla_put_failure;
499 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
500 htonl(helper->expect_class_max + 1)))
501 goto nla_put_failure;
503 for (i = 0; i < helper->expect_class_max + 1; i++) {
504 nest_parms2 = nla_nest_start(skb,
505 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
506 if (nest_parms2 == NULL)
507 goto nla_put_failure;
509 if (nla_put_string(skb, NFCTH_POLICY_NAME,
510 helper->expect_policy[i].name))
511 goto nla_put_failure;
513 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
514 htonl(helper->expect_policy[i].max_expected)))
515 goto nla_put_failure;
517 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
518 htonl(helper->expect_policy[i].timeout)))
519 goto nla_put_failure;
521 nla_nest_end(skb, nest_parms2);
523 nla_nest_end(skb, nest_parms1);
531 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
532 int event, struct nf_conntrack_helper *helper)
534 struct nlmsghdr *nlh;
535 struct nfgenmsg *nfmsg;
536 unsigned int flags = portid ? NLM_F_MULTI : 0;
539 event = nfnl_msg_type(NFNL_SUBSYS_CTHELPER, event);
540 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
544 nfmsg = nlmsg_data(nlh);
545 nfmsg->nfgen_family = AF_UNSPEC;
546 nfmsg->version = NFNETLINK_V0;
549 if (nla_put_string(skb, NFCTH_NAME, helper->name))
550 goto nla_put_failure;
552 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
553 goto nla_put_failure;
555 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
556 goto nla_put_failure;
558 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
559 goto nla_put_failure;
561 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
562 goto nla_put_failure;
564 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
565 status = NFCT_HELPER_STATUS_ENABLED;
567 status = NFCT_HELPER_STATUS_DISABLED;
569 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
570 goto nla_put_failure;
577 nlmsg_cancel(skb, nlh);
582 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
584 struct nf_conntrack_helper *cur, *last;
587 last = (struct nf_conntrack_helper *)cb->args[1];
588 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
590 hlist_for_each_entry_rcu(cur,
591 &nf_ct_helper_hash[cb->args[0]], hnode) {
593 /* skip non-userspace conntrack helpers. */
594 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
602 if (nfnl_cthelper_fill_info(skb,
603 NETLINK_CB(cb->skb).portid,
605 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
606 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
607 cb->args[1] = (unsigned long)cur;
621 static int nfnl_cthelper_get(struct net *net, struct sock *nfnl,
622 struct sk_buff *skb, const struct nlmsghdr *nlh,
623 const struct nlattr * const tb[],
624 struct netlink_ext_ack *extack)
627 struct nf_conntrack_helper *cur;
628 struct sk_buff *skb2;
629 char *helper_name = NULL;
630 struct nf_conntrack_tuple tuple;
631 struct nfnl_cthelper *nlcth;
632 bool tuple_set = false;
634 if (!capable(CAP_NET_ADMIN))
637 if (nlh->nlmsg_flags & NLM_F_DUMP) {
638 struct netlink_dump_control c = {
639 .dump = nfnl_cthelper_dump_table,
641 return netlink_dump_start(nfnl, skb, nlh, &c);
645 helper_name = nla_data(tb[NFCTH_NAME]);
647 if (tb[NFCTH_TUPLE]) {
648 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
655 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
656 cur = &nlcth->helper;
658 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
662 (tuple.src.l3num != cur->tuple.src.l3num ||
663 tuple.dst.protonum != cur->tuple.dst.protonum))
666 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
672 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
674 NFNL_MSG_TYPE(nlh->nlmsg_type),
675 NFNL_MSG_CTHELPER_NEW, cur);
681 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
686 /* this avoids a loop in nfnetlink. */
687 return ret == -EAGAIN ? -ENOBUFS : ret;
692 static int nfnl_cthelper_del(struct net *net, struct sock *nfnl,
693 struct sk_buff *skb, const struct nlmsghdr *nlh,
694 const struct nlattr * const tb[],
695 struct netlink_ext_ack *extack)
697 char *helper_name = NULL;
698 struct nf_conntrack_helper *cur;
699 struct nf_conntrack_tuple tuple;
700 bool tuple_set = false, found = false;
701 struct nfnl_cthelper *nlcth, *n;
704 if (!capable(CAP_NET_ADMIN))
708 helper_name = nla_data(tb[NFCTH_NAME]);
710 if (tb[NFCTH_TUPLE]) {
711 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
719 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
720 cur = &nlcth->helper;
724 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
728 (tuple.src.l3num != cur->tuple.src.l3num ||
729 tuple.dst.protonum != cur->tuple.dst.protonum))
732 if (refcount_dec_if_one(&cur->refcnt)) {
734 nf_conntrack_helper_unregister(cur);
735 kfree(cur->expect_policy);
737 list_del(&nlcth->list);
744 /* Make sure we return success if we flush and there is no helpers */
745 return (found || j == 0) ? 0 : ret;
748 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
749 [NFCTH_NAME] = { .type = NLA_NUL_STRING,
750 .len = NF_CT_HELPER_NAME_LEN-1 },
751 [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
752 [NFCTH_PRIV_DATA_LEN] = { .type = NLA_U32, },
753 [NFCTH_STATUS] = { .type = NLA_U32, },
756 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
757 [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
758 .attr_count = NFCTH_MAX,
759 .policy = nfnl_cthelper_policy },
760 [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
761 .attr_count = NFCTH_MAX,
762 .policy = nfnl_cthelper_policy },
763 [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
764 .attr_count = NFCTH_MAX,
765 .policy = nfnl_cthelper_policy },
768 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
770 .subsys_id = NFNL_SUBSYS_CTHELPER,
771 .cb_count = NFNL_MSG_CTHELPER_MAX,
772 .cb = nfnl_cthelper_cb,
775 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
777 static int __init nfnl_cthelper_init(void)
781 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
783 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
791 static void __exit nfnl_cthelper_exit(void)
793 struct nf_conntrack_helper *cur;
794 struct nfnl_cthelper *nlcth, *n;
796 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
798 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
799 cur = &nlcth->helper;
801 nf_conntrack_helper_unregister(cur);
802 kfree(cur->expect_policy);
807 module_init(nfnl_cthelper_init);
808 module_exit(nfnl_cthelper_exit);