xref: /openbmc/linux/net/sched/act_mirred.c (revision 22246614)
1 /*
2  * net/sched/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 <net/net_namespace.h>
24 #include <net/netlink.h>
25 #include <net/pkt_sched.h>
26 #include <linux/tc_act/tc_mirred.h>
27 #include <net/tc_act/tc_mirred.h>
28 
29 #include <linux/if_arp.h>
30 
31 #define MIRRED_TAB_MASK     7
32 static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
33 static u32 mirred_idx_gen;
34 static DEFINE_RWLOCK(mirred_lock);
35 
36 static struct tcf_hashinfo mirred_hash_info = {
37 	.htab	=	tcf_mirred_ht,
38 	.hmask	=	MIRRED_TAB_MASK,
39 	.lock	=	&mirred_lock,
40 };
41 
42 static inline int tcf_mirred_release(struct tcf_mirred *m, int bind)
43 {
44 	if (m) {
45 		if (bind)
46 			m->tcf_bindcnt--;
47 		m->tcf_refcnt--;
48 		if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
49 			dev_put(m->tcfm_dev);
50 			tcf_hash_destroy(&m->common, &mirred_hash_info);
51 			return 1;
52 		}
53 	}
54 	return 0;
55 }
56 
57 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
58 	[TCA_MIRRED_PARMS]	= { .len = sizeof(struct tc_mirred) },
59 };
60 
61 static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est,
62 			   struct tc_action *a, int ovr, int bind)
63 {
64 	struct nlattr *tb[TCA_MIRRED_MAX + 1];
65 	struct tc_mirred *parm;
66 	struct tcf_mirred *m;
67 	struct tcf_common *pc;
68 	struct net_device *dev = NULL;
69 	int ret = 0, err;
70 	int ok_push = 0;
71 
72 	if (nla == NULL)
73 		return -EINVAL;
74 
75 	err = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
76 	if (err < 0)
77 		return err;
78 
79 	if (tb[TCA_MIRRED_PARMS] == NULL)
80 		return -EINVAL;
81 	parm = nla_data(tb[TCA_MIRRED_PARMS]);
82 
83 	if (parm->ifindex) {
84 		dev = __dev_get_by_index(&init_net, parm->ifindex);
85 		if (dev == NULL)
86 			return -ENODEV;
87 		switch (dev->type) {
88 			case ARPHRD_TUNNEL:
89 			case ARPHRD_TUNNEL6:
90 			case ARPHRD_SIT:
91 			case ARPHRD_IPGRE:
92 			case ARPHRD_VOID:
93 			case ARPHRD_NONE:
94 				ok_push = 0;
95 				break;
96 			default:
97 				ok_push = 1;
98 				break;
99 		}
100 	}
101 
102 	pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
103 	if (!pc) {
104 		if (!parm->ifindex)
105 			return -EINVAL;
106 		pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
107 				     &mirred_idx_gen, &mirred_hash_info);
108 		if (unlikely(!pc))
109 			return -ENOMEM;
110 		ret = ACT_P_CREATED;
111 	} else {
112 		if (!ovr) {
113 			tcf_mirred_release(to_mirred(pc), bind);
114 			return -EEXIST;
115 		}
116 	}
117 	m = to_mirred(pc);
118 
119 	spin_lock_bh(&m->tcf_lock);
120 	m->tcf_action = parm->action;
121 	m->tcfm_eaction = parm->eaction;
122 	if (parm->ifindex) {
123 		m->tcfm_ifindex = parm->ifindex;
124 		if (ret != ACT_P_CREATED)
125 			dev_put(m->tcfm_dev);
126 		m->tcfm_dev = dev;
127 		dev_hold(dev);
128 		m->tcfm_ok_push = ok_push;
129 	}
130 	spin_unlock_bh(&m->tcf_lock);
131 	if (ret == ACT_P_CREATED)
132 		tcf_hash_insert(pc, &mirred_hash_info);
133 
134 	return ret;
135 }
136 
137 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
138 {
139 	struct tcf_mirred *m = a->priv;
140 
141 	if (m)
142 		return tcf_mirred_release(m, bind);
143 	return 0;
144 }
145 
146 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
147 		      struct tcf_result *res)
148 {
149 	struct tcf_mirred *m = a->priv;
150 	struct net_device *dev;
151 	struct sk_buff *skb2 = NULL;
152 	u32 at = G_TC_AT(skb->tc_verd);
153 
154 	spin_lock(&m->tcf_lock);
155 
156 	dev = m->tcfm_dev;
157 	m->tcf_tm.lastuse = jiffies;
158 
159 	if (!(dev->flags&IFF_UP) ) {
160 		if (net_ratelimit())
161 			printk("mirred to Houston: device %s is gone!\n",
162 			       dev->name);
163 bad_mirred:
164 		if (skb2 != NULL)
165 			kfree_skb(skb2);
166 		m->tcf_qstats.overlimits++;
167 		m->tcf_bstats.bytes += skb->len;
168 		m->tcf_bstats.packets++;
169 		spin_unlock(&m->tcf_lock);
170 		/* should we be asking for packet to be dropped?
171 		 * may make sense for redirect case only
172 		*/
173 		return TC_ACT_SHOT;
174 	}
175 
176 	skb2 = skb_act_clone(skb, GFP_ATOMIC);
177 	if (skb2 == NULL)
178 		goto bad_mirred;
179 	if (m->tcfm_eaction != TCA_EGRESS_MIRROR &&
180 	    m->tcfm_eaction != TCA_EGRESS_REDIR) {
181 		if (net_ratelimit())
182 			printk("tcf_mirred unknown action %d\n",
183 			       m->tcfm_eaction);
184 		goto bad_mirred;
185 	}
186 
187 	m->tcf_bstats.bytes += skb2->len;
188 	m->tcf_bstats.packets++;
189 	if (!(at & AT_EGRESS))
190 		if (m->tcfm_ok_push)
191 			skb_push(skb2, skb2->dev->hard_header_len);
192 
193 	/* mirror is always swallowed */
194 	if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
195 		skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
196 
197 	skb2->dev = dev;
198 	skb2->iif = skb->dev->ifindex;
199 	dev_queue_xmit(skb2);
200 	spin_unlock(&m->tcf_lock);
201 	return m->tcf_action;
202 }
203 
204 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
205 {
206 	unsigned char *b = skb_tail_pointer(skb);
207 	struct tcf_mirred *m = a->priv;
208 	struct tc_mirred opt;
209 	struct tcf_t t;
210 
211 	opt.index = m->tcf_index;
212 	opt.action = m->tcf_action;
213 	opt.refcnt = m->tcf_refcnt - ref;
214 	opt.bindcnt = m->tcf_bindcnt - bind;
215 	opt.eaction = m->tcfm_eaction;
216 	opt.ifindex = m->tcfm_ifindex;
217 	NLA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
218 	t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
219 	t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
220 	t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
221 	NLA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
222 	return skb->len;
223 
224 nla_put_failure:
225 	nlmsg_trim(skb, b);
226 	return -1;
227 }
228 
229 static struct tc_action_ops act_mirred_ops = {
230 	.kind		=	"mirred",
231 	.hinfo		=	&mirred_hash_info,
232 	.type		=	TCA_ACT_MIRRED,
233 	.capab		=	TCA_CAP_NONE,
234 	.owner		=	THIS_MODULE,
235 	.act		=	tcf_mirred,
236 	.dump		=	tcf_mirred_dump,
237 	.cleanup	=	tcf_mirred_cleanup,
238 	.lookup		=	tcf_hash_search,
239 	.init		=	tcf_mirred_init,
240 	.walk		=	tcf_generic_walker
241 };
242 
243 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
244 MODULE_DESCRIPTION("Device Mirror/redirect actions");
245 MODULE_LICENSE("GPL");
246 
247 static int __init mirred_init_module(void)
248 {
249 	printk("Mirror/redirect action on\n");
250 	return tcf_register_action(&act_mirred_ops);
251 }
252 
253 static void __exit mirred_cleanup_module(void)
254 {
255 	tcf_unregister_action(&act_mirred_ops);
256 }
257 
258 module_init(mirred_init_module);
259 module_exit(mirred_cleanup_module);
260