act_connmark.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * net/sched/act_connmark.c  netfilter connmark retriever action
  4 * skb mark is over-written
  5 *
  6 * Copyright (c) 2011 Felix Fietkau <nbd@openwrt.org>
  7*/
  8
  9#include <linux/module.h>
 10#include <linux/init.h>
 11#include <linux/kernel.h>
 12#include <linux/skbuff.h>
 13#include <linux/rtnetlink.h>
 14#include <linux/pkt_cls.h>
 15#include <linux/ip.h>
 16#include <linux/ipv6.h>
 17#include <net/netlink.h>
 18#include <net/pkt_sched.h>
 19#include <net/act_api.h>
 20#include <net/pkt_cls.h>
 21#include <uapi/linux/tc_act/tc_connmark.h>
 22#include <net/tc_act/tc_connmark.h>
 23#include <net/tc_wrapper.h>
 24
 25#include <net/netfilter/nf_conntrack.h>
 26#include <net/netfilter/nf_conntrack_core.h>
 27#include <net/netfilter/nf_conntrack_zones.h>
 28
 29static struct tc_action_ops act_connmark_ops;
 30
 31TC_INDIRECT_SCOPE int tcf_connmark_act(struct sk_buff *skb,
 32				       const struct tc_action *a,
 33				       struct tcf_result *res)
 34{
 35	const struct nf_conntrack_tuple_hash *thash;
 36	struct nf_conntrack_tuple tuple;
 37	enum ip_conntrack_info ctinfo;
 38	struct tcf_connmark_info *ca = to_connmark(a);
 39	struct tcf_connmark_parms *parms;
 40	struct nf_conntrack_zone zone;
 41	struct nf_conn *c;
 42	int proto;
 43
 44	tcf_lastuse_update(&ca->tcf_tm);
 45	tcf_action_update_bstats(&ca->common, skb);
 46
 47	parms = rcu_dereference_bh(ca->parms);
 48
 49	switch (skb_protocol(skb, true)) {
 50	case htons(ETH_P_IP):
 51		if (skb->len < sizeof(struct iphdr))
 52			goto out;
 53
 54		proto = NFPROTO_IPV4;
 55		break;
 56	case htons(ETH_P_IPV6):
 57		if (skb->len < sizeof(struct ipv6hdr))
 58			goto out;
 59
 60		proto = NFPROTO_IPV6;
 61		break;
 62	default:
 63		goto out;
 64	}
 65
 66	c = nf_ct_get(skb, &ctinfo);
 67	if (c) {
 68		skb->mark = READ_ONCE(c->mark);
 69		goto count;
 70	}
 71
 72	if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, parms->net,
 73			       &tuple))
 74		goto out;
 75
 76	zone.id = parms->zone;
 77	zone.dir = NF_CT_DEFAULT_ZONE_DIR;
 78
 79	thash = nf_conntrack_find_get(parms->net, &zone, &tuple);
 80	if (!thash)
 81		goto out;
 82
 83	c = nf_ct_tuplehash_to_ctrack(thash);
 84	skb->mark = READ_ONCE(c->mark);
 85	nf_ct_put(c);
 86
 87count:
 88	/* using overlimits stats to count how many packets marked */
 89	tcf_action_inc_overlimit_qstats(&ca->common);
 90out:
 91	return parms->action;
 92}
 93
 94static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
 95	[TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
 96};
 97
 98static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 99			     struct nlattr *est, struct tc_action **a,
100			     struct tcf_proto *tp, u32 flags,
101			     struct netlink_ext_ack *extack)
102{
103	struct tc_action_net *tn = net_generic(net, act_connmark_ops.net_id);
104	struct tcf_connmark_parms *nparms, *oparms;
105	struct nlattr *tb[TCA_CONNMARK_MAX + 1];
106	bool bind = flags & TCA_ACT_FLAGS_BIND;
107	struct tcf_chain *goto_ch = NULL;
108	struct tcf_connmark_info *ci;
109	struct tc_connmark *parm;
110	int ret = 0, err;
111	u32 index;
112
113	if (!nla)
114		return -EINVAL;
115
116	ret = nla_parse_nested_deprecated(tb, TCA_CONNMARK_MAX, nla,
117					  connmark_policy, NULL);
118	if (ret < 0)
119		return ret;
120
121	if (!tb[TCA_CONNMARK_PARMS])
122		return -EINVAL;
123
124	nparms = kzalloc(sizeof(*nparms), GFP_KERNEL);
125	if (!nparms)
126		return -ENOMEM;
127
128	parm = nla_data(tb[TCA_CONNMARK_PARMS]);
129	index = parm->index;
130	ret = tcf_idr_check_alloc(tn, &index, a, bind);
131	if (!ret) {
132		ret = tcf_idr_create_from_flags(tn, index, est, a,
133						&act_connmark_ops, bind, flags);
134		if (ret) {
135			tcf_idr_cleanup(tn, index);
136			err = ret;
137			goto out_free;
138		}
139
140		ci = to_connmark(*a);
141
142		nparms->net = net;
143		nparms->zone = parm->zone;
144
145		ret = ACT_P_CREATED;
146	} else if (ret > 0) {
147		ci = to_connmark(*a);
148		if (bind) {
149			err = ACT_P_BOUND;
150			goto out_free;
151		}
152		if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
153			err = -EEXIST;
154			goto release_idr;
155		}
156
157		nparms->net = rtnl_dereference(ci->parms)->net;
158		nparms->zone = parm->zone;
159
160		ret = 0;
161	} else {
162		err = ret;
163		goto out_free;
164	}
165
166	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
167	if (err < 0)
168		goto release_idr;
169
170	nparms->action = parm->action;
171
172	spin_lock_bh(&ci->tcf_lock);
173	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
174	oparms = rcu_replace_pointer(ci->parms, nparms, lockdep_is_held(&ci->tcf_lock));
175	spin_unlock_bh(&ci->tcf_lock);
176
177	if (goto_ch)
178		tcf_chain_put_by_act(goto_ch);
179
180	if (oparms)
181		kfree_rcu(oparms, rcu);
182
183	return ret;
184
185release_idr:
186	tcf_idr_release(*a, bind);
187out_free:
188	kfree(nparms);
189	return err;
190}
191
192static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
193				    int bind, int ref)
194{
195	const struct tcf_connmark_info *ci = to_connmark(a);
196	unsigned char *b = skb_tail_pointer(skb);
197	const struct tcf_connmark_parms *parms;
198	struct tc_connmark opt;
199	struct tcf_t t;
200
201	memset(&opt, 0, sizeof(opt));
202
203	opt.index   = ci->tcf_index;
204	opt.refcnt  = refcount_read(&ci->tcf_refcnt) - ref;
205	opt.bindcnt = atomic_read(&ci->tcf_bindcnt) - bind;
206
207	rcu_read_lock();
208	parms = rcu_dereference(ci->parms);
209
210	opt.action = parms->action;
211	opt.zone = parms->zone;
212	if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
213		goto nla_put_failure;
214
215	tcf_tm_dump(&t, &ci->tcf_tm);
216	if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
217			  TCA_CONNMARK_PAD))
218		goto nla_put_failure;
219	rcu_read_unlock();
220
221	return skb->len;
222
223nla_put_failure:
224	rcu_read_unlock();
225	nlmsg_trim(skb, b);
226	return -1;
227}
228
229static void tcf_connmark_cleanup(struct tc_action *a)
230{
231	struct tcf_connmark_info *ci = to_connmark(a);
232	struct tcf_connmark_parms *parms;
233
234	parms = rcu_dereference_protected(ci->parms, 1);
235	if (parms)
236		kfree_rcu(parms, rcu);
237}
238
239static struct tc_action_ops act_connmark_ops = {
240	.kind		=	"connmark",
241	.id		=	TCA_ID_CONNMARK,
242	.owner		=	THIS_MODULE,
243	.act		=	tcf_connmark_act,
244	.dump		=	tcf_connmark_dump,
245	.init		=	tcf_connmark_init,
246	.cleanup	=	tcf_connmark_cleanup,
247	.size		=	sizeof(struct tcf_connmark_info),
248};
249MODULE_ALIAS_NET_ACT("connmark");
250
251static __net_init int connmark_init_net(struct net *net)
252{
253	struct tc_action_net *tn = net_generic(net, act_connmark_ops.net_id);
254
255	return tc_action_net_init(net, tn, &act_connmark_ops);
256}
257
258static void __net_exit connmark_exit_net(struct list_head *net_list)
259{
260	tc_action_net_exit(net_list, act_connmark_ops.net_id);
261}
262
263static struct pernet_operations connmark_net_ops = {
264	.init = connmark_init_net,
265	.exit_batch = connmark_exit_net,
266	.id   = &act_connmark_ops.net_id,
267	.size = sizeof(struct tc_action_net),
268};
269
270static int __init connmark_init_module(void)
271{
272	return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
273}
274
275static void __exit connmark_cleanup_module(void)
276{
277	tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
278}
279
280module_init(connmark_init_module);
281module_exit(connmark_cleanup_module);
282MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
283MODULE_DESCRIPTION("Connection tracking mark restoring");
284MODULE_LICENSE("GPL");