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");
35 struct nfnl_cthelper {
36 struct list_head list;
37 struct nf_conntrack_helper helper;
40 static LIST_HEAD(nfnl_cthelper_list);
43 nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
44 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
46 const struct nf_conn_help *help;
47 struct nf_conntrack_helper *helper;
53 /* rcu_read_lock()ed by nf_hook_thresh */
54 helper = rcu_dereference(help->helper);
58 /* This is a user-space helper not yet configured, skip. */
60 (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
61 NF_CT_HELPER_F_USERSPACE)
64 /* If the user-space helper is not available, don't block traffic. */
65 return NF_QUEUE_NR(helper->queue_num) | NF_VERDICT_FLAG_QUEUE_BYPASS;
68 static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
69 [NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
70 [NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
74 nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
75 const struct nlattr *attr)
78 struct nlattr *tb[NFCTH_TUPLE_MAX+1];
80 err = nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr,
81 nfnl_cthelper_tuple_pol, NULL);
85 if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
88 /* Not all fields are initialized so first zero the tuple */
89 memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
91 tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
92 tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
98 nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
100 struct nf_conn_help *help = nfct_help(ct);
105 if (help->helper->data_len == 0)
108 nla_memcpy(help->data, nla_data(attr), sizeof(help->data));
113 nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
115 const struct nf_conn_help *help = nfct_help(ct);
117 if (help->helper->data_len &&
118 nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
119 goto nla_put_failure;
127 static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
128 [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
129 .len = NF_CT_HELPER_NAME_LEN-1 },
130 [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
131 [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
135 nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
136 const struct nlattr *attr)
139 struct nlattr *tb[NFCTH_POLICY_MAX+1];
141 err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr,
142 nfnl_cthelper_expect_pol, NULL);
146 if (!tb[NFCTH_POLICY_NAME] ||
147 !tb[NFCTH_POLICY_EXPECT_MAX] ||
148 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
151 strncpy(expect_policy->name,
152 nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
153 expect_policy->max_expected =
154 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
155 if (expect_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
158 expect_policy->timeout =
159 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
164 static const struct nla_policy
165 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
166 [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
170 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
171 const struct nlattr *attr)
174 struct nf_conntrack_expect_policy *expect_policy;
175 struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
176 unsigned int class_max;
178 ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
179 nfnl_cthelper_expect_policy_set, NULL);
183 if (!tb[NFCTH_POLICY_SET_NUM])
186 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
189 if (class_max > NF_CT_MAX_EXPECT_CLASSES)
192 expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
193 class_max, GFP_KERNEL);
194 if (expect_policy == NULL)
197 for (i = 0; i < class_max; i++) {
198 if (!tb[NFCTH_POLICY_SET+i])
201 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
202 tb[NFCTH_POLICY_SET+i]);
207 helper->expect_class_max = class_max - 1;
208 helper->expect_policy = expect_policy;
211 kfree(expect_policy);
216 nfnl_cthelper_create(const struct nlattr * const tb[],
217 struct nf_conntrack_tuple *tuple)
219 struct nf_conntrack_helper *helper;
220 struct nfnl_cthelper *nfcth;
224 if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
227 nfcth = kzalloc(sizeof(*nfcth), GFP_KERNEL);
230 helper = &nfcth->helper;
232 ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
236 strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
237 size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
238 if (size > FIELD_SIZEOF(struct nf_conn_help, data)) {
243 helper->flags |= NF_CT_HELPER_F_USERSPACE;
244 memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
246 helper->me = THIS_MODULE;
247 helper->help = nfnl_userspace_cthelper;
248 helper->from_nlattr = nfnl_cthelper_from_nlattr;
249 helper->to_nlattr = nfnl_cthelper_to_nlattr;
251 /* Default to queue number zero, this can be updated at any time. */
252 if (tb[NFCTH_QUEUE_NUM])
253 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
255 if (tb[NFCTH_STATUS]) {
256 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
259 case NFCT_HELPER_STATUS_ENABLED:
260 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
262 case NFCT_HELPER_STATUS_DISABLED:
263 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
268 ret = nf_conntrack_helper_register(helper);
272 list_add_tail(&nfcth->list, &nfnl_cthelper_list);
275 kfree(helper->expect_policy);
282 nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy,
283 struct nf_conntrack_expect_policy *new_policy,
284 const struct nlattr *attr)
286 struct nlattr *tb[NFCTH_POLICY_MAX + 1];
289 err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr,
290 nfnl_cthelper_expect_pol, NULL);
294 if (!tb[NFCTH_POLICY_NAME] ||
295 !tb[NFCTH_POLICY_EXPECT_MAX] ||
296 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
299 if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name))
302 new_policy->max_expected =
303 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
304 if (new_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
307 new_policy->timeout =
308 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
313 static int nfnl_cthelper_update_policy_all(struct nlattr *tb[],
314 struct nf_conntrack_helper *helper)
316 struct nf_conntrack_expect_policy new_policy[helper->expect_class_max + 1];
317 struct nf_conntrack_expect_policy *policy;
320 /* Check first that all policy attributes are well-formed, so we don't
321 * leave things in inconsistent state on errors.
323 for (i = 0; i < helper->expect_class_max + 1; i++) {
325 if (!tb[NFCTH_POLICY_SET + i])
328 err = nfnl_cthelper_update_policy_one(&helper->expect_policy[i],
330 tb[NFCTH_POLICY_SET + i]);
334 /* Now we can safely update them. */
335 for (i = 0; i < helper->expect_class_max + 1; i++) {
336 policy = (struct nf_conntrack_expect_policy *)
337 &helper->expect_policy[i];
338 policy->max_expected = new_policy->max_expected;
339 policy->timeout = new_policy->timeout;
345 static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper,
346 const struct nlattr *attr)
348 struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1];
349 unsigned int class_max;
352 err = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
353 nfnl_cthelper_expect_policy_set, NULL);
357 if (!tb[NFCTH_POLICY_SET_NUM])
360 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
361 if (helper->expect_class_max + 1 != class_max)
364 return nfnl_cthelper_update_policy_all(tb, helper);
368 nfnl_cthelper_update(const struct nlattr * const tb[],
369 struct nf_conntrack_helper *helper)
373 if (tb[NFCTH_PRIV_DATA_LEN])
376 if (tb[NFCTH_POLICY]) {
377 ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
381 if (tb[NFCTH_QUEUE_NUM])
382 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
384 if (tb[NFCTH_STATUS]) {
385 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
388 case NFCT_HELPER_STATUS_ENABLED:
389 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
391 case NFCT_HELPER_STATUS_DISABLED:
392 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
399 static int nfnl_cthelper_new(struct net *net, struct sock *nfnl,
400 struct sk_buff *skb, const struct nlmsghdr *nlh,
401 const struct nlattr * const tb[])
403 const char *helper_name;
404 struct nf_conntrack_helper *cur, *helper = NULL;
405 struct nf_conntrack_tuple tuple;
406 struct nfnl_cthelper *nlcth;
409 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
412 helper_name = nla_data(tb[NFCTH_NAME]);
414 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
418 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
419 cur = &nlcth->helper;
421 if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
424 if ((tuple.src.l3num != cur->tuple.src.l3num ||
425 tuple.dst.protonum != cur->tuple.dst.protonum))
428 if (nlh->nlmsg_flags & NLM_F_EXCL)
436 ret = nfnl_cthelper_create(tb, &tuple);
438 ret = nfnl_cthelper_update(tb, helper);
444 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
445 struct nf_conntrack_helper *helper)
447 struct nlattr *nest_parms;
449 nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
450 if (nest_parms == NULL)
451 goto nla_put_failure;
453 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
454 htons(helper->tuple.src.l3num)))
455 goto nla_put_failure;
457 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
458 goto nla_put_failure;
460 nla_nest_end(skb, nest_parms);
468 nfnl_cthelper_dump_policy(struct sk_buff *skb,
469 struct nf_conntrack_helper *helper)
472 struct nlattr *nest_parms1, *nest_parms2;
474 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
475 if (nest_parms1 == NULL)
476 goto nla_put_failure;
478 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
479 htonl(helper->expect_class_max + 1)))
480 goto nla_put_failure;
482 for (i = 0; i < helper->expect_class_max + 1; i++) {
483 nest_parms2 = nla_nest_start(skb,
484 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
485 if (nest_parms2 == NULL)
486 goto nla_put_failure;
488 if (nla_put_string(skb, NFCTH_POLICY_NAME,
489 helper->expect_policy[i].name))
490 goto nla_put_failure;
492 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
493 htonl(helper->expect_policy[i].max_expected)))
494 goto nla_put_failure;
496 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
497 htonl(helper->expect_policy[i].timeout)))
498 goto nla_put_failure;
500 nla_nest_end(skb, nest_parms2);
502 nla_nest_end(skb, nest_parms1);
510 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
511 int event, struct nf_conntrack_helper *helper)
513 struct nlmsghdr *nlh;
514 struct nfgenmsg *nfmsg;
515 unsigned int flags = portid ? NLM_F_MULTI : 0;
518 event = nfnl_msg_type(NFNL_SUBSYS_CTHELPER, event);
519 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
523 nfmsg = nlmsg_data(nlh);
524 nfmsg->nfgen_family = AF_UNSPEC;
525 nfmsg->version = NFNETLINK_V0;
528 if (nla_put_string(skb, NFCTH_NAME, helper->name))
529 goto nla_put_failure;
531 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
532 goto nla_put_failure;
534 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
535 goto nla_put_failure;
537 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
538 goto nla_put_failure;
540 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
541 goto nla_put_failure;
543 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
544 status = NFCT_HELPER_STATUS_ENABLED;
546 status = NFCT_HELPER_STATUS_DISABLED;
548 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
549 goto nla_put_failure;
556 nlmsg_cancel(skb, nlh);
561 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
563 struct nf_conntrack_helper *cur, *last;
566 last = (struct nf_conntrack_helper *)cb->args[1];
567 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
569 hlist_for_each_entry_rcu(cur,
570 &nf_ct_helper_hash[cb->args[0]], hnode) {
572 /* skip non-userspace conntrack helpers. */
573 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
581 if (nfnl_cthelper_fill_info(skb,
582 NETLINK_CB(cb->skb).portid,
584 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
585 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
586 cb->args[1] = (unsigned long)cur;
600 static int nfnl_cthelper_get(struct net *net, struct sock *nfnl,
601 struct sk_buff *skb, const struct nlmsghdr *nlh,
602 const struct nlattr * const tb[])
605 struct nf_conntrack_helper *cur;
606 struct sk_buff *skb2;
607 char *helper_name = NULL;
608 struct nf_conntrack_tuple tuple;
609 struct nfnl_cthelper *nlcth;
610 bool tuple_set = false;
612 if (nlh->nlmsg_flags & NLM_F_DUMP) {
613 struct netlink_dump_control c = {
614 .dump = nfnl_cthelper_dump_table,
616 return netlink_dump_start(nfnl, skb, nlh, &c);
620 helper_name = nla_data(tb[NFCTH_NAME]);
622 if (tb[NFCTH_TUPLE]) {
623 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
630 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
631 cur = &nlcth->helper;
633 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
637 (tuple.src.l3num != cur->tuple.src.l3num ||
638 tuple.dst.protonum != cur->tuple.dst.protonum))
641 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
647 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
649 NFNL_MSG_TYPE(nlh->nlmsg_type),
650 NFNL_MSG_CTHELPER_NEW, cur);
656 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
661 /* this avoids a loop in nfnetlink. */
662 return ret == -EAGAIN ? -ENOBUFS : ret;
667 static int nfnl_cthelper_del(struct net *net, struct sock *nfnl,
668 struct sk_buff *skb, const struct nlmsghdr *nlh,
669 const struct nlattr * const tb[])
671 char *helper_name = NULL;
672 struct nf_conntrack_helper *cur;
673 struct nf_conntrack_tuple tuple;
674 bool tuple_set = false, found = false;
675 struct nfnl_cthelper *nlcth, *n;
679 helper_name = nla_data(tb[NFCTH_NAME]);
681 if (tb[NFCTH_TUPLE]) {
682 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
689 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
690 cur = &nlcth->helper;
694 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
698 (tuple.src.l3num != cur->tuple.src.l3num ||
699 tuple.dst.protonum != cur->tuple.dst.protonum))
703 nf_conntrack_helper_unregister(cur);
704 kfree(cur->expect_policy);
706 list_del(&nlcth->list);
710 /* Make sure we return success if we flush and there is no helpers */
711 return (found || j == 0) ? 0 : -ENOENT;
714 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
715 [NFCTH_NAME] = { .type = NLA_NUL_STRING,
716 .len = NF_CT_HELPER_NAME_LEN-1 },
717 [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
720 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
721 [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
722 .attr_count = NFCTH_MAX,
723 .policy = nfnl_cthelper_policy },
724 [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
725 .attr_count = NFCTH_MAX,
726 .policy = nfnl_cthelper_policy },
727 [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
728 .attr_count = NFCTH_MAX,
729 .policy = nfnl_cthelper_policy },
732 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
734 .subsys_id = NFNL_SUBSYS_CTHELPER,
735 .cb_count = NFNL_MSG_CTHELPER_MAX,
736 .cb = nfnl_cthelper_cb,
739 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
741 static int __init nfnl_cthelper_init(void)
745 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
747 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
755 static void __exit nfnl_cthelper_exit(void)
757 struct nf_conntrack_helper *cur;
758 struct nfnl_cthelper *nlcth, *n;
760 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
762 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
763 cur = &nlcth->helper;
765 nf_conntrack_helper_unregister(cur);
766 kfree(cur->expect_policy);
771 module_init(nfnl_cthelper_init);
772 module_exit(nfnl_cthelper_exit);