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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 <linux/if_arp.h> | |
25 | #include <net/net_namespace.h> | |
26 | #include <net/netlink.h> | |
27 | #include <net/pkt_sched.h> | |
28 | #include <linux/tc_act/tc_mirred.h> | |
29 | #include <net/tc_act/tc_mirred.h> | |
30 | ||
31 | #include <linux/if_arp.h> | |
32 | ||
33 | #define MIRRED_TAB_MASK 7 | |
34 | static LIST_HEAD(mirred_list); | |
35 | static DEFINE_SPINLOCK(mirred_list_lock); | |
36 | ||
37 | static bool tcf_mirred_is_act_redirect(int action) | |
38 | { | |
39 | return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR; | |
40 | } | |
41 | ||
42 | static u32 tcf_mirred_act_direction(int action) | |
43 | { | |
44 | switch (action) { | |
45 | case TCA_EGRESS_REDIR: | |
46 | case TCA_EGRESS_MIRROR: | |
47 | return AT_EGRESS; | |
48 | case TCA_INGRESS_REDIR: | |
49 | case TCA_INGRESS_MIRROR: | |
50 | return AT_INGRESS; | |
51 | default: | |
52 | BUG(); | |
53 | } | |
54 | } | |
55 | ||
56 | static void tcf_mirred_release(struct tc_action *a, int bind) | |
57 | { | |
58 | struct tcf_mirred *m = to_mirred(a); | |
59 | struct net_device *dev; | |
60 | ||
61 | /* We could be called either in a RCU callback or with RTNL lock held. */ | |
62 | spin_lock_bh(&mirred_list_lock); | |
63 | list_del(&m->tcfm_list); | |
64 | dev = rcu_dereference_protected(m->tcfm_dev, 1); | |
65 | if (dev) | |
66 | dev_put(dev); | |
67 | spin_unlock_bh(&mirred_list_lock); | |
68 | } | |
69 | ||
70 | static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { | |
71 | [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, | |
72 | }; | |
73 | ||
74 | static unsigned int mirred_net_id; | |
75 | static struct tc_action_ops act_mirred_ops; | |
76 | ||
77 | static int tcf_mirred_init(struct net *net, struct nlattr *nla, | |
78 | struct nlattr *est, struct tc_action **a, int ovr, | |
79 | int bind) | |
80 | { | |
81 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
82 | struct nlattr *tb[TCA_MIRRED_MAX + 1]; | |
83 | bool mac_header_xmit = false; | |
84 | struct tc_mirred *parm; | |
85 | struct tcf_mirred *m; | |
86 | struct net_device *dev; | |
87 | bool exists = false; | |
88 | int ret; | |
89 | ||
90 | if (nla == NULL) | |
91 | return -EINVAL; | |
92 | ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); | |
93 | if (ret < 0) | |
94 | return ret; | |
95 | if (tb[TCA_MIRRED_PARMS] == NULL) | |
96 | return -EINVAL; | |
97 | parm = nla_data(tb[TCA_MIRRED_PARMS]); | |
98 | ||
99 | exists = tcf_hash_check(tn, parm->index, a, bind); | |
100 | if (exists && bind) | |
101 | return 0; | |
102 | ||
103 | switch (parm->eaction) { | |
104 | case TCA_EGRESS_MIRROR: | |
105 | case TCA_EGRESS_REDIR: | |
106 | case TCA_INGRESS_REDIR: | |
107 | case TCA_INGRESS_MIRROR: | |
108 | break; | |
109 | default: | |
110 | if (exists) | |
111 | tcf_hash_release(*a, bind); | |
112 | return -EINVAL; | |
113 | } | |
114 | if (parm->ifindex) { | |
115 | dev = __dev_get_by_index(net, parm->ifindex); | |
116 | if (dev == NULL) { | |
117 | if (exists) | |
118 | tcf_hash_release(*a, bind); | |
119 | return -ENODEV; | |
120 | } | |
121 | mac_header_xmit = dev_is_mac_header_xmit(dev); | |
122 | } else { | |
123 | dev = NULL; | |
124 | } | |
125 | ||
126 | if (!exists) { | |
127 | if (dev == NULL) | |
128 | return -EINVAL; | |
129 | ret = tcf_hash_create(tn, parm->index, est, a, | |
130 | &act_mirred_ops, bind, true); | |
131 | if (ret) | |
132 | return ret; | |
133 | ret = ACT_P_CREATED; | |
134 | } else { | |
135 | tcf_hash_release(*a, bind); | |
136 | if (!ovr) | |
137 | return -EEXIST; | |
138 | } | |
139 | m = to_mirred(*a); | |
140 | ||
141 | ASSERT_RTNL(); | |
142 | m->tcf_action = parm->action; | |
143 | m->tcfm_eaction = parm->eaction; | |
144 | if (dev != NULL) { | |
145 | m->tcfm_ifindex = parm->ifindex; | |
146 | if (ret != ACT_P_CREATED) | |
147 | dev_put(rcu_dereference_protected(m->tcfm_dev, 1)); | |
148 | dev_hold(dev); | |
149 | rcu_assign_pointer(m->tcfm_dev, dev); | |
150 | m->tcfm_mac_header_xmit = mac_header_xmit; | |
151 | } | |
152 | ||
153 | if (ret == ACT_P_CREATED) { | |
154 | spin_lock_bh(&mirred_list_lock); | |
155 | list_add(&m->tcfm_list, &mirred_list); | |
156 | spin_unlock_bh(&mirred_list_lock); | |
157 | tcf_hash_insert(tn, *a); | |
158 | } | |
159 | ||
160 | return ret; | |
161 | } | |
162 | ||
163 | static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, | |
164 | struct tcf_result *res) | |
165 | { | |
166 | struct tcf_mirred *m = to_mirred(a); | |
167 | bool m_mac_header_xmit; | |
168 | struct net_device *dev; | |
169 | struct sk_buff *skb2; | |
170 | int retval, err = 0; | |
171 | int m_eaction; | |
172 | int mac_len; | |
173 | u32 at; | |
174 | ||
175 | tcf_lastuse_update(&m->tcf_tm); | |
176 | bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb); | |
177 | ||
178 | rcu_read_lock(); | |
179 | m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit); | |
180 | m_eaction = READ_ONCE(m->tcfm_eaction); | |
181 | retval = READ_ONCE(m->tcf_action); | |
182 | dev = rcu_dereference(m->tcfm_dev); | |
183 | if (unlikely(!dev)) { | |
184 | pr_notice_once("tc mirred: target device is gone\n"); | |
185 | goto out; | |
186 | } | |
187 | ||
188 | if (unlikely(!(dev->flags & IFF_UP))) { | |
189 | net_notice_ratelimited("tc mirred to Houston: device %s is down\n", | |
190 | dev->name); | |
191 | goto out; | |
192 | } | |
193 | ||
194 | at = G_TC_AT(skb->tc_verd); | |
195 | skb2 = skb_clone(skb, GFP_ATOMIC); | |
196 | if (!skb2) | |
197 | goto out; | |
198 | ||
199 | /* If action's target direction differs than filter's direction, | |
200 | * and devices expect a mac header on xmit, then mac push/pull is | |
201 | * needed. | |
202 | */ | |
203 | if (at != tcf_mirred_act_direction(m_eaction) && m_mac_header_xmit) { | |
204 | if (at & AT_EGRESS) { | |
205 | /* caught at egress, act ingress: pull mac */ | |
206 | mac_len = skb_network_header(skb) - skb_mac_header(skb); | |
207 | skb_pull_rcsum(skb2, mac_len); | |
208 | } else { | |
209 | /* caught at ingress, act egress: push mac */ | |
210 | skb_push_rcsum(skb2, skb->mac_len); | |
211 | } | |
212 | } | |
213 | ||
214 | /* mirror is always swallowed */ | |
215 | if (tcf_mirred_is_act_redirect(m_eaction)) | |
216 | skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at); | |
217 | ||
218 | skb2->skb_iif = skb->dev->ifindex; | |
219 | skb2->dev = dev; | |
220 | if (tcf_mirred_act_direction(m_eaction) & AT_EGRESS) | |
221 | err = dev_queue_xmit(skb2); | |
222 | else | |
223 | err = netif_receive_skb(skb2); | |
224 | ||
225 | if (err) { | |
226 | out: | |
227 | qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats)); | |
228 | if (tcf_mirred_is_act_redirect(m_eaction)) | |
229 | retval = TC_ACT_SHOT; | |
230 | } | |
231 | rcu_read_unlock(); | |
232 | ||
233 | return retval; | |
234 | } | |
235 | ||
236 | static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets, | |
237 | u64 lastuse) | |
238 | { | |
239 | struct tcf_mirred *m = to_mirred(a); | |
240 | struct tcf_t *tm = &m->tcf_tm; | |
241 | ||
242 | _bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets); | |
243 | tm->lastuse = lastuse; | |
244 | } | |
245 | ||
246 | static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, | |
247 | int ref) | |
248 | { | |
249 | unsigned char *b = skb_tail_pointer(skb); | |
250 | struct tcf_mirred *m = to_mirred(a); | |
251 | struct tc_mirred opt = { | |
252 | .index = m->tcf_index, | |
253 | .action = m->tcf_action, | |
254 | .refcnt = m->tcf_refcnt - ref, | |
255 | .bindcnt = m->tcf_bindcnt - bind, | |
256 | .eaction = m->tcfm_eaction, | |
257 | .ifindex = m->tcfm_ifindex, | |
258 | }; | |
259 | struct tcf_t t; | |
260 | ||
261 | if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) | |
262 | goto nla_put_failure; | |
263 | ||
264 | tcf_tm_dump(&t, &m->tcf_tm); | |
265 | if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD)) | |
266 | goto nla_put_failure; | |
267 | return skb->len; | |
268 | ||
269 | nla_put_failure: | |
270 | nlmsg_trim(skb, b); | |
271 | return -1; | |
272 | } | |
273 | ||
274 | static int tcf_mirred_walker(struct net *net, struct sk_buff *skb, | |
275 | struct netlink_callback *cb, int type, | |
276 | const struct tc_action_ops *ops) | |
277 | { | |
278 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
279 | ||
280 | return tcf_generic_walker(tn, skb, cb, type, ops); | |
281 | } | |
282 | ||
283 | static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index) | |
284 | { | |
285 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
286 | ||
287 | return tcf_hash_search(tn, a, index); | |
288 | } | |
289 | ||
290 | static int mirred_device_event(struct notifier_block *unused, | |
291 | unsigned long event, void *ptr) | |
292 | { | |
293 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); | |
294 | struct tcf_mirred *m; | |
295 | ||
296 | ASSERT_RTNL(); | |
297 | if (event == NETDEV_UNREGISTER) { | |
298 | spin_lock_bh(&mirred_list_lock); | |
299 | list_for_each_entry(m, &mirred_list, tcfm_list) { | |
300 | if (rcu_access_pointer(m->tcfm_dev) == dev) { | |
301 | dev_put(dev); | |
302 | /* Note : no rcu grace period necessary, as | |
303 | * net_device are already rcu protected. | |
304 | */ | |
305 | RCU_INIT_POINTER(m->tcfm_dev, NULL); | |
306 | } | |
307 | } | |
308 | spin_unlock_bh(&mirred_list_lock); | |
309 | } | |
310 | ||
311 | return NOTIFY_DONE; | |
312 | } | |
313 | ||
314 | static struct notifier_block mirred_device_notifier = { | |
315 | .notifier_call = mirred_device_event, | |
316 | }; | |
317 | ||
318 | static int tcf_mirred_device(const struct tc_action *a, struct net *net, | |
319 | struct net_device **mirred_dev) | |
320 | { | |
321 | int ifindex = tcf_mirred_ifindex(a); | |
322 | ||
323 | *mirred_dev = __dev_get_by_index(net, ifindex); | |
324 | if (!*mirred_dev) | |
325 | return -EINVAL; | |
326 | return 0; | |
327 | } | |
328 | ||
329 | static struct tc_action_ops act_mirred_ops = { | |
330 | .kind = "mirred", | |
331 | .type = TCA_ACT_MIRRED, | |
332 | .owner = THIS_MODULE, | |
333 | .act = tcf_mirred, | |
334 | .stats_update = tcf_stats_update, | |
335 | .dump = tcf_mirred_dump, | |
336 | .cleanup = tcf_mirred_release, | |
337 | .init = tcf_mirred_init, | |
338 | .walk = tcf_mirred_walker, | |
339 | .lookup = tcf_mirred_search, | |
340 | .size = sizeof(struct tcf_mirred), | |
341 | .get_dev = tcf_mirred_device, | |
342 | }; | |
343 | ||
344 | static __net_init int mirred_init_net(struct net *net) | |
345 | { | |
346 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
347 | ||
348 | return tc_action_net_init(tn, &act_mirred_ops, MIRRED_TAB_MASK); | |
349 | } | |
350 | ||
351 | static void __net_exit mirred_exit_net(struct net *net) | |
352 | { | |
353 | struct tc_action_net *tn = net_generic(net, mirred_net_id); | |
354 | ||
355 | tc_action_net_exit(tn); | |
356 | } | |
357 | ||
358 | static struct pernet_operations mirred_net_ops = { | |
359 | .init = mirred_init_net, | |
360 | .exit = mirred_exit_net, | |
361 | .id = &mirred_net_id, | |
362 | .size = sizeof(struct tc_action_net), | |
363 | }; | |
364 | ||
365 | MODULE_AUTHOR("Jamal Hadi Salim(2002)"); | |
366 | MODULE_DESCRIPTION("Device Mirror/redirect actions"); | |
367 | MODULE_LICENSE("GPL"); | |
368 | ||
369 | static int __init mirred_init_module(void) | |
370 | { | |
371 | int err = register_netdevice_notifier(&mirred_device_notifier); | |
372 | if (err) | |
373 | return err; | |
374 | ||
375 | pr_info("Mirror/redirect action on\n"); | |
376 | return tcf_register_action(&act_mirred_ops, &mirred_net_ops); | |
377 | } | |
378 | ||
379 | static void __exit mirred_cleanup_module(void) | |
380 | { | |
381 | tcf_unregister_action(&act_mirred_ops, &mirred_net_ops); | |
382 | unregister_netdevice_notifier(&mirred_device_notifier); | |
383 | } | |
384 | ||
385 | module_init(mirred_init_module); | |
386 | module_exit(mirred_cleanup_module); |