1/*
2 * net/sched/act_mirred.c	packet mirroring and redirect actions
3 *
4 *		This program is free software; you can redistribute it and/or
5 *		modify it under the terms of the GNU General Public License
6 *		as published by the Free Software Foundation; either version
7 *		2 of the License, or (at your option) any later version.
8 *
9 * Authors:	Jamal Hadi Salim (2002-4)
10 *
11 * TODO: Add ingress support (and socket redirect support)
12 *
13 */
14
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/string.h>
18#include <linux/errno.h>
19#include <linux/skbuff.h>
20#include <linux/rtnetlink.h>
21#include <linux/module.h>
22#include <linux/init.h>
23#include <linux/gfp.h>
24#include <net/net_namespace.h>
25#include <net/netlink.h>
26#include <net/pkt_sched.h>
27#include <linux/tc_act/tc_mirred.h>
28#include <net/tc_act/tc_mirred.h>
29
30#include <linux/if_arp.h>
31
32#define MIRRED_TAB_MASK     7
33static LIST_HEAD(mirred_list);
34
35static void tcf_mirred_release(struct tc_action *a, int bind)
36{
37	struct tcf_mirred *m = to_mirred(a);
38	list_del(&m->tcfm_list);
39	if (m->tcfm_dev)
40		dev_put(m->tcfm_dev);
41}
42
43static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
44	[TCA_MIRRED_PARMS]	= { .len = sizeof(struct tc_mirred) },
45};
46
47static int tcf_mirred_init(struct net *net, struct nlattr *nla,
48			   struct nlattr *est, struct tc_action *a, int ovr,
49			   int bind)
50{
51	struct nlattr *tb[TCA_MIRRED_MAX + 1];
52	struct tc_mirred *parm;
53	struct tcf_mirred *m;
54	struct net_device *dev;
55	int ret, ok_push = 0;
56
57	if (nla == NULL)
58		return -EINVAL;
59	ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
60	if (ret < 0)
61		return ret;
62	if (tb[TCA_MIRRED_PARMS] == NULL)
63		return -EINVAL;
64	parm = nla_data(tb[TCA_MIRRED_PARMS]);
65	switch (parm->eaction) {
66	case TCA_EGRESS_MIRROR:
67	case TCA_EGRESS_REDIR:
68		break;
69	default:
70		return -EINVAL;
71	}
72	if (parm->ifindex) {
73		dev = __dev_get_by_index(net, parm->ifindex);
74		if (dev == NULL)
75			return -ENODEV;
76		switch (dev->type) {
77		case ARPHRD_TUNNEL:
78		case ARPHRD_TUNNEL6:
79		case ARPHRD_SIT:
80		case ARPHRD_IPGRE:
81		case ARPHRD_VOID:
82		case ARPHRD_NONE:
83			ok_push = 0;
84			break;
85		default:
86			ok_push = 1;
87			break;
88		}
89	} else {
90		dev = NULL;
91	}
92
93	if (!tcf_hash_check(parm->index, a, bind)) {
94		if (dev == NULL)
95			return -EINVAL;
96		ret = tcf_hash_create(parm->index, est, a, sizeof(*m), bind);
97		if (ret)
98			return ret;
99		ret = ACT_P_CREATED;
100	} else {
101		if (!ovr) {
102			tcf_hash_release(a, bind);
103			return -EEXIST;
104		}
105	}
106	m = to_mirred(a);
107
108	spin_lock_bh(&m->tcf_lock);
109	m->tcf_action = parm->action;
110	m->tcfm_eaction = parm->eaction;
111	if (dev != NULL) {
112		m->tcfm_ifindex = parm->ifindex;
113		if (ret != ACT_P_CREATED)
114			dev_put(m->tcfm_dev);
115		dev_hold(dev);
116		m->tcfm_dev = dev;
117		m->tcfm_ok_push = ok_push;
118	}
119	spin_unlock_bh(&m->tcf_lock);
120	if (ret == ACT_P_CREATED) {
121		list_add(&m->tcfm_list, &mirred_list);
122		tcf_hash_insert(a);
123	}
124
125	return ret;
126}
127
128static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
129		      struct tcf_result *res)
130{
131	struct tcf_mirred *m = a->priv;
132	struct net_device *dev;
133	struct sk_buff *skb2;
134	u32 at;
135	int retval, err = 1;
136
137	spin_lock(&m->tcf_lock);
138	m->tcf_tm.lastuse = jiffies;
139	bstats_update(&m->tcf_bstats, skb);
140
141	dev = m->tcfm_dev;
142	if (!dev) {
143		printk_once(KERN_NOTICE "tc mirred: target device is gone\n");
144		goto out;
145	}
146
147	if (!(dev->flags & IFF_UP)) {
148		net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
149				       dev->name);
150		goto out;
151	}
152
153	at = G_TC_AT(skb->tc_verd);
154	skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action);
155	if (skb2 == NULL)
156		goto out;
157
158	if (!(at & AT_EGRESS)) {
159		if (m->tcfm_ok_push)
160			skb_push(skb2, skb->mac_len);
161	}
162
163	/* mirror is always swallowed */
164	if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
165		skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
166
167	skb2->skb_iif = skb->dev->ifindex;
168	skb2->dev = dev;
169	skb_sender_cpu_clear(skb2);
170	err = dev_queue_xmit(skb2);
171
172out:
173	if (err) {
174		m->tcf_qstats.overlimits++;
175		if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
176			retval = TC_ACT_SHOT;
177		else
178			retval = m->tcf_action;
179	} else
180		retval = m->tcf_action;
181	spin_unlock(&m->tcf_lock);
182
183	return retval;
184}
185
186static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
187{
188	unsigned char *b = skb_tail_pointer(skb);
189	struct tcf_mirred *m = a->priv;
190	struct tc_mirred opt = {
191		.index   = m->tcf_index,
192		.action  = m->tcf_action,
193		.refcnt  = m->tcf_refcnt - ref,
194		.bindcnt = m->tcf_bindcnt - bind,
195		.eaction = m->tcfm_eaction,
196		.ifindex = m->tcfm_ifindex,
197	};
198	struct tcf_t t;
199
200	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
201		goto nla_put_failure;
202	t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
203	t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
204	t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
205	if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t))
206		goto nla_put_failure;
207	return skb->len;
208
209nla_put_failure:
210	nlmsg_trim(skb, b);
211	return -1;
212}
213
214static int mirred_device_event(struct notifier_block *unused,
215			       unsigned long event, void *ptr)
216{
217	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
218	struct tcf_mirred *m;
219
220	if (event == NETDEV_UNREGISTER)
221		list_for_each_entry(m, &mirred_list, tcfm_list) {
222			spin_lock_bh(&m->tcf_lock);
223			if (m->tcfm_dev == dev) {
224				dev_put(dev);
225				m->tcfm_dev = NULL;
226			}
227			spin_unlock_bh(&m->tcf_lock);
228		}
229
230	return NOTIFY_DONE;
231}
232
233static struct notifier_block mirred_device_notifier = {
234	.notifier_call = mirred_device_event,
235};
236
237static struct tc_action_ops act_mirred_ops = {
238	.kind		=	"mirred",
239	.type		=	TCA_ACT_MIRRED,
240	.owner		=	THIS_MODULE,
241	.act		=	tcf_mirred,
242	.dump		=	tcf_mirred_dump,
243	.cleanup	=	tcf_mirred_release,
244	.init		=	tcf_mirred_init,
245};
246
247MODULE_AUTHOR("Jamal Hadi Salim(2002)");
248MODULE_DESCRIPTION("Device Mirror/redirect actions");
249MODULE_LICENSE("GPL");
250
251static int __init mirred_init_module(void)
252{
253	int err = register_netdevice_notifier(&mirred_device_notifier);
254	if (err)
255		return err;
256
257	pr_info("Mirror/redirect action on\n");
258	return tcf_register_action(&act_mirred_ops, MIRRED_TAB_MASK);
259}
260
261static void __exit mirred_cleanup_module(void)
262{
263	tcf_unregister_action(&act_mirred_ops);
264	unregister_netdevice_notifier(&mirred_device_notifier);
265}
266
267module_init(mirred_init_module);
268module_exit(mirred_cleanup_module);
269