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_slow */
55 helper = rcu_dereference(help->helper);
59 /* This is an 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, nfnl_cthelper_tuple_pol);
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 memcpy(help->data, nla_data(attr), help->helper->data_len);
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, nfnl_cthelper_expect_pol);
145 if (!tb[NFCTH_POLICY_NAME] ||
146 !tb[NFCTH_POLICY_EXPECT_MAX] ||
147 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
150 strncpy(expect_policy->name,
151 nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
152 expect_policy->max_expected =
153 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
154 expect_policy->timeout =
155 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
160 static const struct nla_policy
161 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
162 [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
166 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
167 const struct nlattr *attr)
170 struct nf_conntrack_expect_policy *expect_policy;
171 struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
172 unsigned int class_max;
174 ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
175 nfnl_cthelper_expect_policy_set);
179 if (!tb[NFCTH_POLICY_SET_NUM])
182 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
185 if (class_max > NF_CT_MAX_EXPECT_CLASSES)
188 expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
189 class_max, GFP_KERNEL);
190 if (expect_policy == NULL)
193 for (i = 0; i < class_max; i++) {
194 if (!tb[NFCTH_POLICY_SET+i])
197 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
198 tb[NFCTH_POLICY_SET+i]);
203 helper->expect_class_max = class_max - 1;
204 helper->expect_policy = expect_policy;
207 kfree(expect_policy);
212 nfnl_cthelper_create(const struct nlattr * const tb[],
213 struct nf_conntrack_tuple *tuple)
215 struct nf_conntrack_helper *helper;
216 struct nfnl_cthelper *nfcth;
219 if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
222 nfcth = kzalloc(sizeof(*nfcth), GFP_KERNEL);
225 helper = &nfcth->helper;
227 ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
231 strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
232 helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
233 helper->flags |= NF_CT_HELPER_F_USERSPACE;
234 memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
236 helper->me = THIS_MODULE;
237 helper->help = nfnl_userspace_cthelper;
238 helper->from_nlattr = nfnl_cthelper_from_nlattr;
239 helper->to_nlattr = nfnl_cthelper_to_nlattr;
241 /* Default to queue number zero, this can be updated at any time. */
242 if (tb[NFCTH_QUEUE_NUM])
243 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
245 if (tb[NFCTH_STATUS]) {
246 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
249 case NFCT_HELPER_STATUS_ENABLED:
250 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
252 case NFCT_HELPER_STATUS_DISABLED:
253 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
258 ret = nf_conntrack_helper_register(helper);
262 list_add_tail(&nfcth->list, &nfnl_cthelper_list);
265 kfree(helper->expect_policy);
272 nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy,
273 struct nf_conntrack_expect_policy *new_policy,
274 const struct nlattr *attr)
276 struct nlattr *tb[NFCTH_POLICY_MAX + 1];
279 err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr,
280 nfnl_cthelper_expect_pol);
284 if (!tb[NFCTH_POLICY_NAME] ||
285 !tb[NFCTH_POLICY_EXPECT_MAX] ||
286 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
289 if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name))
292 new_policy->max_expected =
293 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
294 new_policy->timeout =
295 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
300 static int nfnl_cthelper_update_policy_all(struct nlattr *tb[],
301 struct nf_conntrack_helper *helper)
303 struct nf_conntrack_expect_policy new_policy[helper->expect_class_max + 1];
304 struct nf_conntrack_expect_policy *policy;
307 /* Check first that all policy attributes are well-formed, so we don't
308 * leave things in inconsistent state on errors.
310 for (i = 0; i < helper->expect_class_max + 1; i++) {
312 if (!tb[NFCTH_POLICY_SET + i])
315 err = nfnl_cthelper_update_policy_one(&helper->expect_policy[i],
317 tb[NFCTH_POLICY_SET + i]);
321 /* Now we can safely update them. */
322 for (i = 0; i < helper->expect_class_max + 1; i++) {
323 policy = (struct nf_conntrack_expect_policy *)
324 &helper->expect_policy[i];
325 policy->max_expected = new_policy->max_expected;
326 policy->timeout = new_policy->timeout;
332 static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper,
333 const struct nlattr *attr)
335 struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1];
336 unsigned int class_max;
339 err = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
340 nfnl_cthelper_expect_policy_set);
344 if (!tb[NFCTH_POLICY_SET_NUM])
347 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
348 if (helper->expect_class_max + 1 != class_max)
351 return nfnl_cthelper_update_policy_all(tb, helper);
355 nfnl_cthelper_update(const struct nlattr * const tb[],
356 struct nf_conntrack_helper *helper)
361 if (tb[NFCTH_PRIV_DATA_LEN]) {
362 size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
363 if (size != helper->data_len)
367 if (tb[NFCTH_POLICY]) {
368 ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
372 if (tb[NFCTH_QUEUE_NUM])
373 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
375 if (tb[NFCTH_STATUS]) {
376 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
379 case NFCT_HELPER_STATUS_ENABLED:
380 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
382 case NFCT_HELPER_STATUS_DISABLED:
383 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
391 nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb,
392 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
394 const char *helper_name;
395 struct nf_conntrack_helper *cur, *helper = NULL;
396 struct nf_conntrack_tuple tuple;
397 struct nfnl_cthelper *nlcth;
400 if (!capable(CAP_NET_ADMIN))
403 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
406 helper_name = nla_data(tb[NFCTH_NAME]);
408 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
412 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
413 cur = &nlcth->helper;
415 if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
418 if ((tuple.src.l3num != cur->tuple.src.l3num ||
419 tuple.dst.protonum != cur->tuple.dst.protonum))
422 if (nlh->nlmsg_flags & NLM_F_EXCL)
430 ret = nfnl_cthelper_create(tb, &tuple);
432 ret = nfnl_cthelper_update(tb, helper);
438 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
439 struct nf_conntrack_helper *helper)
441 struct nlattr *nest_parms;
443 nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
444 if (nest_parms == NULL)
445 goto nla_put_failure;
447 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
448 htons(helper->tuple.src.l3num)))
449 goto nla_put_failure;
451 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
452 goto nla_put_failure;
454 nla_nest_end(skb, nest_parms);
462 nfnl_cthelper_dump_policy(struct sk_buff *skb,
463 struct nf_conntrack_helper *helper)
466 struct nlattr *nest_parms1, *nest_parms2;
468 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
469 if (nest_parms1 == NULL)
470 goto nla_put_failure;
472 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
473 htonl(helper->expect_class_max + 1)))
474 goto nla_put_failure;
476 for (i = 0; i < helper->expect_class_max + 1; i++) {
477 nest_parms2 = nla_nest_start(skb,
478 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
479 if (nest_parms2 == NULL)
480 goto nla_put_failure;
482 if (nla_put_string(skb, NFCTH_POLICY_NAME,
483 helper->expect_policy[i].name))
484 goto nla_put_failure;
486 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
487 htonl(helper->expect_policy[i].max_expected)))
488 goto nla_put_failure;
490 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
491 htonl(helper->expect_policy[i].timeout)))
492 goto nla_put_failure;
494 nla_nest_end(skb, nest_parms2);
496 nla_nest_end(skb, nest_parms1);
504 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
505 int event, struct nf_conntrack_helper *helper)
507 struct nlmsghdr *nlh;
508 struct nfgenmsg *nfmsg;
509 unsigned int flags = portid ? NLM_F_MULTI : 0;
512 event |= NFNL_SUBSYS_CTHELPER << 8;
513 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
517 nfmsg = nlmsg_data(nlh);
518 nfmsg->nfgen_family = AF_UNSPEC;
519 nfmsg->version = NFNETLINK_V0;
522 if (nla_put_string(skb, NFCTH_NAME, helper->name))
523 goto nla_put_failure;
525 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
526 goto nla_put_failure;
528 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
529 goto nla_put_failure;
531 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
532 goto nla_put_failure;
534 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
535 goto nla_put_failure;
537 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
538 status = NFCT_HELPER_STATUS_ENABLED;
540 status = NFCT_HELPER_STATUS_DISABLED;
542 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
543 goto nla_put_failure;
550 nlmsg_cancel(skb, nlh);
555 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
557 struct nf_conntrack_helper *cur, *last;
560 last = (struct nf_conntrack_helper *)cb->args[1];
561 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
563 hlist_for_each_entry_rcu(cur,
564 &nf_ct_helper_hash[cb->args[0]], hnode) {
566 /* skip non-userspace conntrack helpers. */
567 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
575 if (nfnl_cthelper_fill_info(skb,
576 NETLINK_CB(cb->skb).portid,
578 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
579 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
580 cb->args[1] = (unsigned long)cur;
595 nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb,
596 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
599 struct nf_conntrack_helper *cur;
600 struct sk_buff *skb2;
601 char *helper_name = NULL;
602 struct nf_conntrack_tuple tuple;
603 struct nfnl_cthelper *nlcth;
604 bool tuple_set = false;
606 if (!capable(CAP_NET_ADMIN))
609 if (nlh->nlmsg_flags & NLM_F_DUMP) {
610 struct netlink_dump_control c = {
611 .dump = nfnl_cthelper_dump_table,
613 return netlink_dump_start(nfnl, skb, nlh, &c);
617 helper_name = nla_data(tb[NFCTH_NAME]);
619 if (tb[NFCTH_TUPLE]) {
620 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
627 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
628 cur = &nlcth->helper;
630 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
634 (tuple.src.l3num != cur->tuple.src.l3num ||
635 tuple.dst.protonum != cur->tuple.dst.protonum))
638 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
644 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
646 NFNL_MSG_TYPE(nlh->nlmsg_type),
647 NFNL_MSG_CTHELPER_NEW, cur);
653 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
658 /* this avoids a loop in nfnetlink. */
659 return ret == -EAGAIN ? -ENOBUFS : ret;
665 nfnl_cthelper_del(struct sock *nfnl, struct sk_buff *skb,
666 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
668 char *helper_name = NULL;
669 struct nf_conntrack_helper *cur;
670 struct nf_conntrack_tuple tuple;
671 bool tuple_set = false, found = false;
672 struct nfnl_cthelper *nlcth, *n;
675 if (!capable(CAP_NET_ADMIN))
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, },
718 [NFCTH_PRIV_DATA_LEN] = { .type = NLA_U32, },
719 [NFCTH_STATUS] = { .type = NLA_U32, },
722 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
723 [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
724 .attr_count = NFCTH_MAX,
725 .policy = nfnl_cthelper_policy },
726 [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
727 .attr_count = NFCTH_MAX,
728 .policy = nfnl_cthelper_policy },
729 [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
730 .attr_count = NFCTH_MAX,
731 .policy = nfnl_cthelper_policy },
734 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
736 .subsys_id = NFNL_SUBSYS_CTHELPER,
737 .cb_count = NFNL_MSG_CTHELPER_MAX,
738 .cb = nfnl_cthelper_cb,
741 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
743 static int __init nfnl_cthelper_init(void)
747 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
749 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
757 static void __exit nfnl_cthelper_exit(void)
759 struct nf_conntrack_helper *cur;
760 struct nfnl_cthelper *nlcth, *n;
762 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
764 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
765 cur = &nlcth->helper;
767 nf_conntrack_helper_unregister(cur);
768 kfree(cur->expect_policy);
773 module_init(nfnl_cthelper_init);
774 module_exit(nfnl_cthelper_exit);