1/*
2 * net/sched/act_connmark.c  netfilter connmark retriever action
3 * skb mark is over-written
4 *
5 * Copyright (c) 2011 Felix Fietkau <nbd@openwrt.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11*/
12
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/kernel.h>
16#include <linux/skbuff.h>
17#include <linux/rtnetlink.h>
18#include <linux/pkt_cls.h>
19#include <linux/ip.h>
20#include <linux/ipv6.h>
21#include <net/netlink.h>
22#include <net/pkt_sched.h>
23#include <net/act_api.h>
24#include <uapi/linux/tc_act/tc_connmark.h>
25#include <net/tc_act/tc_connmark.h>
26
27#include <net/netfilter/nf_conntrack.h>
28#include <net/netfilter/nf_conntrack_core.h>
29#include <net/netfilter/nf_conntrack_zones.h>
30
31#define CONNMARK_TAB_MASK     3
32
33static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
34			struct tcf_result *res)
35{
36	const struct nf_conntrack_tuple_hash *thash;
37	struct nf_conntrack_tuple tuple;
38	enum ip_conntrack_info ctinfo;
39	struct tcf_connmark_info *ca = a->priv;
40	struct nf_conn *c;
41	int proto;
42
43	spin_lock(&ca->tcf_lock);
44	ca->tcf_tm.lastuse = jiffies;
45	bstats_update(&ca->tcf_bstats, skb);
46
47	if (skb->protocol == htons(ETH_P_IP)) {
48		if (skb->len < sizeof(struct iphdr))
49			goto out;
50
51		proto = NFPROTO_IPV4;
52	} else if (skb->protocol == htons(ETH_P_IPV6)) {
53		if (skb->len < sizeof(struct ipv6hdr))
54			goto out;
55
56		proto = NFPROTO_IPV6;
57	} else {
58		goto out;
59	}
60
61	c = nf_ct_get(skb, &ctinfo);
62	if (c) {
63		skb->mark = c->mark;
64		/* using overlimits stats to count how many packets marked */
65		ca->tcf_qstats.overlimits++;
66		goto out;
67	}
68
69	if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
70			       proto, &tuple))
71		goto out;
72
73	thash = nf_conntrack_find_get(dev_net(skb->dev), ca->zone, &tuple);
74	if (!thash)
75		goto out;
76
77	c = nf_ct_tuplehash_to_ctrack(thash);
78	/* using overlimits stats to count how many packets marked */
79	ca->tcf_qstats.overlimits++;
80	skb->mark = c->mark;
81	nf_ct_put(c);
82
83out:
84	spin_unlock(&ca->tcf_lock);
85	return ca->tcf_action;
86}
87
88static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
89	[TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
90};
91
92static int tcf_connmark_init(struct net *net, struct nlattr *nla,
93			     struct nlattr *est, struct tc_action *a,
94			     int ovr, int bind)
95{
96	struct nlattr *tb[TCA_CONNMARK_MAX + 1];
97	struct tcf_connmark_info *ci;
98	struct tc_connmark *parm;
99	int ret = 0;
100
101	if (!nla)
102		return -EINVAL;
103
104	ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy);
105	if (ret < 0)
106		return ret;
107
108	parm = nla_data(tb[TCA_CONNMARK_PARMS]);
109
110	if (!tcf_hash_check(parm->index, a, bind)) {
111		ret = tcf_hash_create(parm->index, est, a, sizeof(*ci), bind);
112		if (ret)
113			return ret;
114
115		ci = to_connmark(a);
116		ci->tcf_action = parm->action;
117		ci->zone = parm->zone;
118
119		tcf_hash_insert(a);
120		ret = ACT_P_CREATED;
121	} else {
122		ci = to_connmark(a);
123		if (bind)
124			return 0;
125		tcf_hash_release(a, bind);
126		if (!ovr)
127			return -EEXIST;
128		/* replacing action and zone */
129		ci->tcf_action = parm->action;
130		ci->zone = parm->zone;
131	}
132
133	return ret;
134}
135
136static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
137				    int bind, int ref)
138{
139	unsigned char *b = skb_tail_pointer(skb);
140	struct tcf_connmark_info *ci = a->priv;
141
142	struct tc_connmark opt = {
143		.index   = ci->tcf_index,
144		.refcnt  = ci->tcf_refcnt - ref,
145		.bindcnt = ci->tcf_bindcnt - bind,
146		.action  = ci->tcf_action,
147		.zone   = ci->zone,
148	};
149	struct tcf_t t;
150
151	if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
152		goto nla_put_failure;
153
154	t.install = jiffies_to_clock_t(jiffies - ci->tcf_tm.install);
155	t.lastuse = jiffies_to_clock_t(jiffies - ci->tcf_tm.lastuse);
156	t.expires = jiffies_to_clock_t(ci->tcf_tm.expires);
157	if (nla_put(skb, TCA_CONNMARK_TM, sizeof(t), &t))
158		goto nla_put_failure;
159
160	return skb->len;
161nla_put_failure:
162	nlmsg_trim(skb, b);
163	return -1;
164}
165
166static struct tc_action_ops act_connmark_ops = {
167	.kind		=	"connmark",
168	.type		=	TCA_ACT_CONNMARK,
169	.owner		=	THIS_MODULE,
170	.act		=	tcf_connmark,
171	.dump		=	tcf_connmark_dump,
172	.init		=	tcf_connmark_init,
173};
174
175static int __init connmark_init_module(void)
176{
177	return tcf_register_action(&act_connmark_ops, CONNMARK_TAB_MASK);
178}
179
180static void __exit connmark_cleanup_module(void)
181{
182	tcf_unregister_action(&act_connmark_ops);
183}
184
185module_init(connmark_init_module);
186module_exit(connmark_cleanup_module);
187MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
188MODULE_DESCRIPTION("Connection tracking mark restoring");
189MODULE_LICENSE("GPL");
190
191