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
33 static LIST_HEAD(mirred_list);
34 static DEFINE_SPINLOCK(mirred_list_lock);
35
tcf_mirred_release(struct tc_action * a,int bind)36 static void tcf_mirred_release(struct tc_action *a, int bind)
37 {
38 struct tcf_mirred *m = to_mirred(a);
39 struct net_device *dev;
40
41 /* We could be called either in a RCU callback or with RTNL lock held. */
42 spin_lock_bh(&mirred_list_lock);
43 list_del(&m->tcfm_list);
44 dev = rcu_dereference_protected(m->tcfm_dev, 1);
45 if (dev)
46 dev_put(dev);
47 spin_unlock_bh(&mirred_list_lock);
48 }
49
50 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
51 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
52 };
53
tcf_mirred_init(struct net * net,struct nlattr * nla,struct nlattr * est,struct tc_action * a,int ovr,int bind)54 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
55 struct nlattr *est, struct tc_action *a, int ovr,
56 int bind)
57 {
58 struct nlattr *tb[TCA_MIRRED_MAX + 1];
59 struct tc_mirred *parm;
60 struct tcf_mirred *m;
61 struct net_device *dev;
62 int ret, ok_push = 0;
63
64 if (nla == NULL)
65 return -EINVAL;
66 ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
67 if (ret < 0)
68 return ret;
69 if (tb[TCA_MIRRED_PARMS] == NULL)
70 return -EINVAL;
71 parm = nla_data(tb[TCA_MIRRED_PARMS]);
72 switch (parm->eaction) {
73 case TCA_EGRESS_MIRROR:
74 case TCA_EGRESS_REDIR:
75 break;
76 default:
77 return -EINVAL;
78 }
79 if (parm->ifindex) {
80 dev = __dev_get_by_index(net, parm->ifindex);
81 if (dev == NULL)
82 return -ENODEV;
83 switch (dev->type) {
84 case ARPHRD_TUNNEL:
85 case ARPHRD_TUNNEL6:
86 case ARPHRD_SIT:
87 case ARPHRD_IPGRE:
88 case ARPHRD_VOID:
89 case ARPHRD_NONE:
90 ok_push = 0;
91 break;
92 default:
93 ok_push = 1;
94 break;
95 }
96 } else {
97 dev = NULL;
98 }
99
100 if (!tcf_hash_check(parm->index, a, bind)) {
101 if (dev == NULL)
102 return -EINVAL;
103 ret = tcf_hash_create(parm->index, est, a, sizeof(*m),
104 bind, true);
105 if (ret)
106 return ret;
107 ret = ACT_P_CREATED;
108 } else {
109 if (bind)
110 return 0;
111
112 tcf_hash_release(a, bind);
113 if (!ovr)
114 return -EEXIST;
115 }
116 m = to_mirred(a);
117
118 ASSERT_RTNL();
119 m->tcf_action = parm->action;
120 m->tcfm_eaction = parm->eaction;
121 if (dev != NULL) {
122 m->tcfm_ifindex = parm->ifindex;
123 if (ret != ACT_P_CREATED)
124 dev_put(rcu_dereference_protected(m->tcfm_dev, 1));
125 dev_hold(dev);
126 rcu_assign_pointer(m->tcfm_dev, dev);
127 m->tcfm_ok_push = ok_push;
128 }
129
130 if (ret == ACT_P_CREATED) {
131 spin_lock_bh(&mirred_list_lock);
132 list_add(&m->tcfm_list, &mirred_list);
133 spin_unlock_bh(&mirred_list_lock);
134 tcf_hash_insert(a);
135 }
136
137 return ret;
138 }
139
tcf_mirred(struct sk_buff * skb,const struct tc_action * a,struct tcf_result * res)140 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
141 struct tcf_result *res)
142 {
143 struct tcf_mirred *m = a->priv;
144 struct net_device *dev;
145 struct sk_buff *skb2;
146 int retval, err;
147 u32 at;
148
149 tcf_lastuse_update(&m->tcf_tm);
150
151 bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
152
153 rcu_read_lock();
154 retval = READ_ONCE(m->tcf_action);
155 dev = rcu_dereference(m->tcfm_dev);
156 if (unlikely(!dev)) {
157 pr_notice_once("tc mirred: target device is gone\n");
158 goto out;
159 }
160
161 if (unlikely(!(dev->flags & IFF_UP))) {
162 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
163 dev->name);
164 goto out;
165 }
166
167 at = G_TC_AT(skb->tc_verd);
168 skb2 = skb_clone(skb, GFP_ATOMIC);
169 if (!skb2)
170 goto out;
171
172 if (!(at & AT_EGRESS)) {
173 if (m->tcfm_ok_push)
174 skb_push_rcsum(skb2, skb->mac_len);
175 }
176
177 /* mirror is always swallowed */
178 if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
179 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
180
181 skb2->skb_iif = skb->dev->ifindex;
182 skb2->dev = dev;
183 skb_sender_cpu_clear(skb2);
184 err = dev_queue_xmit(skb2);
185
186 if (err) {
187 out:
188 qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
189 if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
190 retval = TC_ACT_SHOT;
191 }
192 rcu_read_unlock();
193
194 return retval;
195 }
196
tcf_mirred_dump(struct sk_buff * skb,struct tc_action * a,int bind,int ref)197 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
198 {
199 unsigned char *b = skb_tail_pointer(skb);
200 struct tcf_mirred *m = a->priv;
201 struct tc_mirred opt = {
202 .index = m->tcf_index,
203 .action = m->tcf_action,
204 .refcnt = m->tcf_refcnt - ref,
205 .bindcnt = m->tcf_bindcnt - bind,
206 .eaction = m->tcfm_eaction,
207 .ifindex = m->tcfm_ifindex,
208 };
209 struct tcf_t t;
210
211 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
212 goto nla_put_failure;
213 t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
214 t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
215 t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
216 if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t))
217 goto nla_put_failure;
218 return skb->len;
219
220 nla_put_failure:
221 nlmsg_trim(skb, b);
222 return -1;
223 }
224
mirred_device_event(struct notifier_block * unused,unsigned long event,void * ptr)225 static int mirred_device_event(struct notifier_block *unused,
226 unsigned long event, void *ptr)
227 {
228 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
229 struct tcf_mirred *m;
230
231 ASSERT_RTNL();
232 if (event == NETDEV_UNREGISTER) {
233 spin_lock_bh(&mirred_list_lock);
234 list_for_each_entry(m, &mirred_list, tcfm_list) {
235 if (rcu_access_pointer(m->tcfm_dev) == dev) {
236 dev_put(dev);
237 /* Note : no rcu grace period necessary, as
238 * net_device are already rcu protected.
239 */
240 RCU_INIT_POINTER(m->tcfm_dev, NULL);
241 }
242 }
243 spin_unlock_bh(&mirred_list_lock);
244 }
245
246 return NOTIFY_DONE;
247 }
248
249 static struct notifier_block mirred_device_notifier = {
250 .notifier_call = mirred_device_event,
251 };
252
253 static struct tc_action_ops act_mirred_ops = {
254 .kind = "mirred",
255 .type = TCA_ACT_MIRRED,
256 .owner = THIS_MODULE,
257 .act = tcf_mirred,
258 .dump = tcf_mirred_dump,
259 .cleanup = tcf_mirred_release,
260 .init = tcf_mirred_init,
261 };
262
263 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
264 MODULE_DESCRIPTION("Device Mirror/redirect actions");
265 MODULE_LICENSE("GPL");
266
mirred_init_module(void)267 static int __init mirred_init_module(void)
268 {
269 int err = register_netdevice_notifier(&mirred_device_notifier);
270 if (err)
271 return err;
272
273 pr_info("Mirror/redirect action on\n");
274 return tcf_register_action(&act_mirred_ops, MIRRED_TAB_MASK);
275 }
276
mirred_cleanup_module(void)277 static void __exit mirred_cleanup_module(void)
278 {
279 tcf_unregister_action(&act_mirred_ops);
280 unregister_netdevice_notifier(&mirred_device_notifier);
281 }
282
283 module_init(mirred_init_module);
284 module_exit(mirred_cleanup_module);
285