xref: /openbmc/linux/net/sched/act_mirred.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 <asm/uaccess.h>
16 #include <asm/system.h>
17 #include <asm/bitops.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/string.h>
21 #include <linux/mm.h>
22 #include <linux/socket.h>
23 #include <linux/sockios.h>
24 #include <linux/in.h>
25 #include <linux/errno.h>
26 #include <linux/interrupt.h>
27 #include <linux/netdevice.h>
28 #include <linux/skbuff.h>
29 #include <linux/rtnetlink.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/proc_fs.h>
33 #include <net/netlink.h>
34 #include <net/sock.h>
35 #include <net/pkt_sched.h>
36 #include <linux/tc_act/tc_mirred.h>
37 #include <net/tc_act/tc_mirred.h>
38 
39 #include <linux/etherdevice.h>
40 #include <linux/if_arp.h>
41 
42 #define MIRRED_TAB_MASK     7
43 static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
44 static u32 mirred_idx_gen;
45 static DEFINE_RWLOCK(mirred_lock);
46 
47 static struct tcf_hashinfo mirred_hash_info = {
48 	.htab	=	tcf_mirred_ht,
49 	.hmask	=	MIRRED_TAB_MASK,
50 	.lock	=	&mirred_lock,
51 };
52 
53 static inline int tcf_mirred_release(struct tcf_mirred *m, int bind)
54 {
55 	if (m) {
56 		if (bind)
57 			m->tcf_bindcnt--;
58 		m->tcf_refcnt--;
59 		if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
60 			dev_put(m->tcfm_dev);
61 			tcf_hash_destroy(&m->common, &mirred_hash_info);
62 			return 1;
63 		}
64 	}
65 	return 0;
66 }
67 
68 static int tcf_mirred_init(struct rtattr *rta, struct rtattr *est,
69 			   struct tc_action *a, int ovr, int bind)
70 {
71 	struct rtattr *tb[TCA_MIRRED_MAX];
72 	struct tc_mirred *parm;
73 	struct tcf_mirred *m;
74 	struct tcf_common *pc;
75 	struct net_device *dev = NULL;
76 	int ret = 0;
77 	int ok_push = 0;
78 
79 	if (rta == NULL || rtattr_parse_nested(tb, TCA_MIRRED_MAX, rta) < 0)
80 		return -EINVAL;
81 
82 	if (tb[TCA_MIRRED_PARMS-1] == NULL ||
83 	    RTA_PAYLOAD(tb[TCA_MIRRED_PARMS-1]) < sizeof(*parm))
84 		return -EINVAL;
85 	parm = RTA_DATA(tb[TCA_MIRRED_PARMS-1]);
86 
87 	if (parm->ifindex) {
88 		dev = __dev_get_by_index(parm->ifindex);
89 		if (dev == NULL)
90 			return -ENODEV;
91 		switch (dev->type) {
92 			case ARPHRD_TUNNEL:
93 			case ARPHRD_TUNNEL6:
94 			case ARPHRD_SIT:
95 			case ARPHRD_IPGRE:
96 			case ARPHRD_VOID:
97 			case ARPHRD_NONE:
98 				ok_push = 0;
99 				break;
100 			default:
101 				ok_push = 1;
102 				break;
103 		}
104 	}
105 
106 	pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
107 	if (!pc) {
108 		if (!parm->ifindex)
109 			return -EINVAL;
110 		pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
111 				     &mirred_idx_gen, &mirred_hash_info);
112 		if (unlikely(!pc))
113 			return -ENOMEM;
114 		ret = ACT_P_CREATED;
115 	} else {
116 		if (!ovr) {
117 			tcf_mirred_release(to_mirred(pc), bind);
118 			return -EEXIST;
119 		}
120 	}
121 	m = to_mirred(pc);
122 
123 	spin_lock_bh(&m->tcf_lock);
124 	m->tcf_action = parm->action;
125 	m->tcfm_eaction = parm->eaction;
126 	if (parm->ifindex) {
127 		m->tcfm_ifindex = parm->ifindex;
128 		if (ret != ACT_P_CREATED)
129 			dev_put(m->tcfm_dev);
130 		m->tcfm_dev = dev;
131 		dev_hold(dev);
132 		m->tcfm_ok_push = ok_push;
133 	}
134 	spin_unlock_bh(&m->tcf_lock);
135 	if (ret == ACT_P_CREATED)
136 		tcf_hash_insert(pc, &mirred_hash_info);
137 
138 	return ret;
139 }
140 
141 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
142 {
143 	struct tcf_mirred *m = a->priv;
144 
145 	if (m)
146 		return tcf_mirred_release(m, bind);
147 	return 0;
148 }
149 
150 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
151 		      struct tcf_result *res)
152 {
153 	struct tcf_mirred *m = a->priv;
154 	struct net_device *dev;
155 	struct sk_buff *skb2 = NULL;
156 	u32 at = G_TC_AT(skb->tc_verd);
157 
158 	spin_lock(&m->tcf_lock);
159 
160 	dev = m->tcfm_dev;
161 	m->tcf_tm.lastuse = jiffies;
162 
163 	if (!(dev->flags&IFF_UP) ) {
164 		if (net_ratelimit())
165 			printk("mirred to Houston: device %s is gone!\n",
166 			       dev->name);
167 bad_mirred:
168 		if (skb2 != NULL)
169 			kfree_skb(skb2);
170 		m->tcf_qstats.overlimits++;
171 		m->tcf_bstats.bytes += skb->len;
172 		m->tcf_bstats.packets++;
173 		spin_unlock(&m->tcf_lock);
174 		/* should we be asking for packet to be dropped?
175 		 * may make sense for redirect case only
176 		*/
177 		return TC_ACT_SHOT;
178 	}
179 
180 	skb2 = skb_clone(skb, GFP_ATOMIC);
181 	if (skb2 == NULL)
182 		goto bad_mirred;
183 	if (m->tcfm_eaction != TCA_EGRESS_MIRROR &&
184 	    m->tcfm_eaction != TCA_EGRESS_REDIR) {
185 		if (net_ratelimit())
186 			printk("tcf_mirred unknown action %d\n",
187 			       m->tcfm_eaction);
188 		goto bad_mirred;
189 	}
190 
191 	m->tcf_bstats.bytes += skb2->len;
192 	m->tcf_bstats.packets++;
193 	if (!(at & AT_EGRESS))
194 		if (m->tcfm_ok_push)
195 			skb_push(skb2, skb2->dev->hard_header_len);
196 
197 	/* mirror is always swallowed */
198 	if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
199 		skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
200 
201 	skb2->dev = dev;
202 	skb2->iif = skb->dev->ifindex;
203 	dev_queue_xmit(skb2);
204 	spin_unlock(&m->tcf_lock);
205 	return m->tcf_action;
206 }
207 
208 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
209 {
210 	unsigned char *b = skb_tail_pointer(skb);
211 	struct tcf_mirred *m = a->priv;
212 	struct tc_mirred opt;
213 	struct tcf_t t;
214 
215 	opt.index = m->tcf_index;
216 	opt.action = m->tcf_action;
217 	opt.refcnt = m->tcf_refcnt - ref;
218 	opt.bindcnt = m->tcf_bindcnt - bind;
219 	opt.eaction = m->tcfm_eaction;
220 	opt.ifindex = m->tcfm_ifindex;
221 	RTA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
222 	t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
223 	t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
224 	t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
225 	RTA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
226 	return skb->len;
227 
228 rtattr_failure:
229 	nlmsg_trim(skb, b);
230 	return -1;
231 }
232 
233 static struct tc_action_ops act_mirred_ops = {
234 	.kind		=	"mirred",
235 	.hinfo		=	&mirred_hash_info,
236 	.type		=	TCA_ACT_MIRRED,
237 	.capab		=	TCA_CAP_NONE,
238 	.owner		=	THIS_MODULE,
239 	.act		=	tcf_mirred,
240 	.dump		=	tcf_mirred_dump,
241 	.cleanup	=	tcf_mirred_cleanup,
242 	.lookup		=	tcf_hash_search,
243 	.init		=	tcf_mirred_init,
244 	.walk		=	tcf_generic_walker
245 };
246 
247 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
248 MODULE_DESCRIPTION("Device Mirror/redirect actions");
249 MODULE_LICENSE("GPL");
250 
251 static int __init mirred_init_module(void)
252 {
253 	printk("Mirror/redirect action on\n");
254 	return tcf_register_action(&act_mirred_ops);
255 }
256 
257 static void __exit mirred_cleanup_module(void)
258 {
259 	tcf_unregister_action(&act_mirred_ops);
260 }
261 
262 module_init(mirred_init_module);
263 module_exit(mirred_cleanup_module);
264