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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 | ||
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 | ||
54 | static int mirred_net_id; | |
55 | static struct tc_action_ops act_mirred_ops; | |
56 | ||
57 | static int tcf_mirred_init(struct net *net, struct nlattr *nla, | |
58 | struct nlattr *est, struct tc_action **a, int ovr, | |
59 | int bind) | |
60 | { | |
61 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
62 | struct nlattr *tb[TCA_MIRRED_MAX + 1]; | |
63 | struct tc_mirred *parm; | |
64 | struct tcf_mirred *m; | |
65 | struct net_device *dev; | |
66 | int ret, ok_push = 0; | |
67 | bool exists = false; | |
68 | ||
69 | if (nla == NULL) | |
70 | return -EINVAL; | |
71 | ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); | |
72 | if (ret < 0) | |
73 | return ret; | |
74 | if (tb[TCA_MIRRED_PARMS] == NULL) | |
75 | return -EINVAL; | |
76 | parm = nla_data(tb[TCA_MIRRED_PARMS]); | |
77 | ||
78 | exists = tcf_hash_check(tn, parm->index, a, bind); | |
79 | if (exists && bind) | |
80 | return 0; | |
81 | ||
82 | switch (parm->eaction) { | |
83 | case TCA_EGRESS_MIRROR: | |
84 | case TCA_EGRESS_REDIR: | |
85 | break; | |
86 | default: | |
87 | if (exists) | |
88 | tcf_hash_release(*a, bind); | |
89 | return -EINVAL; | |
90 | } | |
91 | if (parm->ifindex) { | |
92 | dev = __dev_get_by_index(net, parm->ifindex); | |
93 | if (dev == NULL) { | |
94 | if (exists) | |
95 | tcf_hash_release(*a, bind); | |
96 | return -ENODEV; | |
97 | } | |
98 | switch (dev->type) { | |
99 | case ARPHRD_TUNNEL: | |
100 | case ARPHRD_TUNNEL6: | |
101 | case ARPHRD_SIT: | |
102 | case ARPHRD_IPGRE: | |
103 | case ARPHRD_VOID: | |
104 | case ARPHRD_NONE: | |
105 | ok_push = 0; | |
106 | break; | |
107 | default: | |
108 | ok_push = 1; | |
109 | break; | |
110 | } | |
111 | } else { | |
112 | dev = NULL; | |
113 | } | |
114 | ||
115 | if (!exists) { | |
116 | if (dev == NULL) | |
117 | return -EINVAL; | |
118 | ret = tcf_hash_create(tn, parm->index, est, a, | |
119 | &act_mirred_ops, bind, true); | |
120 | if (ret) | |
121 | return ret; | |
122 | ret = ACT_P_CREATED; | |
123 | } else { | |
124 | tcf_hash_release(*a, bind); | |
125 | if (!ovr) | |
126 | return -EEXIST; | |
127 | } | |
128 | m = to_mirred(*a); | |
129 | ||
130 | ASSERT_RTNL(); | |
131 | m->tcf_action = parm->action; | |
132 | m->tcfm_eaction = parm->eaction; | |
133 | if (dev != NULL) { | |
134 | m->tcfm_ifindex = parm->ifindex; | |
135 | if (ret != ACT_P_CREATED) | |
136 | dev_put(rcu_dereference_protected(m->tcfm_dev, 1)); | |
137 | dev_hold(dev); | |
138 | rcu_assign_pointer(m->tcfm_dev, dev); | |
139 | m->tcfm_ok_push = ok_push; | |
140 | } | |
141 | ||
142 | if (ret == ACT_P_CREATED) { | |
143 | spin_lock_bh(&mirred_list_lock); | |
144 | list_add(&m->tcfm_list, &mirred_list); | |
145 | spin_unlock_bh(&mirred_list_lock); | |
146 | tcf_hash_insert(tn, *a); | |
147 | } | |
148 | ||
149 | return ret; | |
150 | } | |
151 | ||
152 | static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, | |
153 | struct tcf_result *res) | |
154 | { | |
155 | struct tcf_mirred *m = to_mirred(a); | |
156 | struct net_device *dev; | |
157 | struct sk_buff *skb2; | |
158 | int retval, err; | |
159 | u32 at; | |
160 | ||
161 | tcf_lastuse_update(&m->tcf_tm); | |
162 | bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb); | |
163 | ||
164 | rcu_read_lock(); | |
165 | retval = READ_ONCE(m->tcf_action); | |
166 | dev = rcu_dereference(m->tcfm_dev); | |
167 | if (unlikely(!dev)) { | |
168 | pr_notice_once("tc mirred: target device is gone\n"); | |
169 | goto out; | |
170 | } | |
171 | ||
172 | if (unlikely(!(dev->flags & IFF_UP))) { | |
173 | net_notice_ratelimited("tc mirred to Houston: device %s is down\n", | |
174 | dev->name); | |
175 | goto out; | |
176 | } | |
177 | ||
178 | at = G_TC_AT(skb->tc_verd); | |
179 | skb2 = skb_clone(skb, GFP_ATOMIC); | |
180 | if (!skb2) | |
181 | goto out; | |
182 | ||
183 | if (!(at & AT_EGRESS)) { | |
184 | if (m->tcfm_ok_push) | |
185 | skb_push_rcsum(skb2, skb->mac_len); | |
186 | } | |
187 | ||
188 | /* mirror is always swallowed */ | |
189 | if (m->tcfm_eaction != TCA_EGRESS_MIRROR) | |
190 | skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at); | |
191 | ||
192 | skb2->skb_iif = skb->dev->ifindex; | |
193 | skb2->dev = dev; | |
194 | err = dev_queue_xmit(skb2); | |
195 | ||
196 | if (err) { | |
197 | out: | |
198 | qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats)); | |
199 | if (m->tcfm_eaction != TCA_EGRESS_MIRROR) | |
200 | retval = TC_ACT_SHOT; | |
201 | } | |
202 | rcu_read_unlock(); | |
203 | ||
204 | return retval; | |
205 | } | |
206 | ||
207 | static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) | |
208 | { | |
209 | unsigned char *b = skb_tail_pointer(skb); | |
210 | struct tcf_mirred *m = to_mirred(a); | |
211 | struct tc_mirred opt = { | |
212 | .index = m->tcf_index, | |
213 | .action = m->tcf_action, | |
214 | .refcnt = m->tcf_refcnt - ref, | |
215 | .bindcnt = m->tcf_bindcnt - bind, | |
216 | .eaction = m->tcfm_eaction, | |
217 | .ifindex = m->tcfm_ifindex, | |
218 | }; | |
219 | struct tcf_t t; | |
220 | ||
221 | if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) | |
222 | goto nla_put_failure; | |
223 | ||
224 | tcf_tm_dump(&t, &m->tcf_tm); | |
225 | if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD)) | |
226 | goto nla_put_failure; | |
227 | return skb->len; | |
228 | ||
229 | nla_put_failure: | |
230 | nlmsg_trim(skb, b); | |
231 | return -1; | |
232 | } | |
233 | ||
234 | static int tcf_mirred_walker(struct net *net, struct sk_buff *skb, | |
235 | struct netlink_callback *cb, int type, | |
236 | const struct tc_action_ops *ops) | |
237 | { | |
238 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
239 | ||
240 | return tcf_generic_walker(tn, skb, cb, type, ops); | |
241 | } | |
242 | ||
243 | static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index) | |
244 | { | |
245 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
246 | ||
247 | return tcf_hash_search(tn, a, index); | |
248 | } | |
249 | ||
250 | static int mirred_device_event(struct notifier_block *unused, | |
251 | unsigned long event, void *ptr) | |
252 | { | |
253 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); | |
254 | struct tcf_mirred *m; | |
255 | ||
256 | ASSERT_RTNL(); | |
257 | if (event == NETDEV_UNREGISTER) { | |
258 | spin_lock_bh(&mirred_list_lock); | |
259 | list_for_each_entry(m, &mirred_list, tcfm_list) { | |
260 | if (rcu_access_pointer(m->tcfm_dev) == dev) { | |
261 | dev_put(dev); | |
262 | /* Note : no rcu grace period necessary, as | |
263 | * net_device are already rcu protected. | |
264 | */ | |
265 | RCU_INIT_POINTER(m->tcfm_dev, NULL); | |
266 | } | |
267 | } | |
268 | spin_unlock_bh(&mirred_list_lock); | |
269 | } | |
270 | ||
271 | return NOTIFY_DONE; | |
272 | } | |
273 | ||
274 | static struct notifier_block mirred_device_notifier = { | |
275 | .notifier_call = mirred_device_event, | |
276 | }; | |
277 | ||
278 | static struct tc_action_ops act_mirred_ops = { | |
279 | .kind = "mirred", | |
280 | .type = TCA_ACT_MIRRED, | |
281 | .owner = THIS_MODULE, | |
282 | .act = tcf_mirred, | |
283 | .dump = tcf_mirred_dump, | |
284 | .cleanup = tcf_mirred_release, | |
285 | .init = tcf_mirred_init, | |
286 | .walk = tcf_mirred_walker, | |
287 | .lookup = tcf_mirred_search, | |
288 | .size = sizeof(struct tcf_mirred), | |
289 | }; | |
290 | ||
291 | static __net_init int mirred_init_net(struct net *net) | |
292 | { | |
293 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
294 | ||
295 | return tc_action_net_init(tn, &act_mirred_ops, MIRRED_TAB_MASK); | |
296 | } | |
297 | ||
298 | static void __net_exit mirred_exit_net(struct net *net) | |
299 | { | |
300 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
301 | ||
302 | tc_action_net_exit(tn); | |
303 | } | |
304 | ||
305 | static struct pernet_operations mirred_net_ops = { | |
306 | .init = mirred_init_net, | |
307 | .exit = mirred_exit_net, | |
308 | .id = &mirred_net_id, | |
309 | .size = sizeof(struct tc_action_net), | |
310 | }; | |
311 | ||
312 | MODULE_AUTHOR("Jamal Hadi Salim(2002)"); | |
313 | MODULE_DESCRIPTION("Device Mirror/redirect actions"); | |
314 | MODULE_LICENSE("GPL"); | |
315 | ||
316 | static int __init mirred_init_module(void) | |
317 | { | |
318 | int err = register_netdevice_notifier(&mirred_device_notifier); | |
319 | if (err) | |
320 | return err; | |
321 | ||
322 | pr_info("Mirror/redirect action on\n"); | |
323 | return tcf_register_action(&act_mirred_ops, &mirred_net_ops); | |
324 | } | |
325 | ||
326 | static void __exit mirred_cleanup_module(void) | |
327 | { | |
328 | tcf_unregister_action(&act_mirred_ops, &mirred_net_ops); | |
329 | unregister_netdevice_notifier(&mirred_device_notifier); | |
330 | } | |
331 | ||
332 | module_init(mirred_init_module); | |
333 | module_exit(mirred_cleanup_module); |