1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * net/sched/act_mirred.c packet mirroring and redirect actions
4 *
5 * Authors: Jamal Hadi Salim (2002-4)
6 *
7 * TODO: Add ingress support (and socket redirect support)
8 */
9
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13 #include <linux/errno.h>
14 #include <linux/skbuff.h>
15 #include <linux/rtnetlink.h>
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/gfp.h>
19 #include <linux/if_arp.h>
20 #include <net/net_namespace.h>
21 #include <net/netlink.h>
22 #include <net/dst.h>
23 #include <net/pkt_sched.h>
24 #include <net/pkt_cls.h>
25 #include <linux/tc_act/tc_mirred.h>
26 #include <net/tc_act/tc_mirred.h>
27
28 static LIST_HEAD(mirred_list);
29 static DEFINE_SPINLOCK(mirred_list_lock);
30
31 #define MIRRED_RECURSION_LIMIT 4
32 static DEFINE_PER_CPU(unsigned int, mirred_rec_level);
33
tcf_mirred_is_act_redirect(int action)34 static bool tcf_mirred_is_act_redirect(int action)
35 {
36 return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR;
37 }
38
tcf_mirred_act_wants_ingress(int action)39 static bool tcf_mirred_act_wants_ingress(int action)
40 {
41 switch (action) {
42 case TCA_EGRESS_REDIR:
43 case TCA_EGRESS_MIRROR:
44 return false;
45 case TCA_INGRESS_REDIR:
46 case TCA_INGRESS_MIRROR:
47 return true;
48 default:
49 BUG();
50 }
51 }
52
tcf_mirred_can_reinsert(int action)53 static bool tcf_mirred_can_reinsert(int action)
54 {
55 switch (action) {
56 case TC_ACT_SHOT:
57 case TC_ACT_STOLEN:
58 case TC_ACT_QUEUED:
59 case TC_ACT_TRAP:
60 return true;
61 }
62 return false;
63 }
64
tcf_mirred_dev_dereference(struct tcf_mirred * m)65 static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m)
66 {
67 return rcu_dereference_protected(m->tcfm_dev,
68 lockdep_is_held(&m->tcf_lock));
69 }
70
tcf_mirred_release(struct tc_action * a)71 static void tcf_mirred_release(struct tc_action *a)
72 {
73 struct tcf_mirred *m = to_mirred(a);
74 struct net_device *dev;
75
76 spin_lock(&mirred_list_lock);
77 list_del(&m->tcfm_list);
78 spin_unlock(&mirred_list_lock);
79
80 /* last reference to action, no need to lock */
81 dev = rcu_dereference_protected(m->tcfm_dev, 1);
82 netdev_put(dev, &m->tcfm_dev_tracker);
83 }
84
85 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
86 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
87 };
88
89 static struct tc_action_ops act_mirred_ops;
90
tcf_mirred_init(struct net * net,struct nlattr * nla,struct nlattr * est,struct tc_action ** a,struct tcf_proto * tp,u32 flags,struct netlink_ext_ack * extack)91 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
92 struct nlattr *est, struct tc_action **a,
93 struct tcf_proto *tp,
94 u32 flags, struct netlink_ext_ack *extack)
95 {
96 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
97 bool bind = flags & TCA_ACT_FLAGS_BIND;
98 struct nlattr *tb[TCA_MIRRED_MAX + 1];
99 struct tcf_chain *goto_ch = NULL;
100 bool mac_header_xmit = false;
101 struct tc_mirred *parm;
102 struct tcf_mirred *m;
103 bool exists = false;
104 int ret, err;
105 u32 index;
106
107 if (!nla) {
108 NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
109 return -EINVAL;
110 }
111 ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla,
112 mirred_policy, extack);
113 if (ret < 0)
114 return ret;
115 if (!tb[TCA_MIRRED_PARMS]) {
116 NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
117 return -EINVAL;
118 }
119 parm = nla_data(tb[TCA_MIRRED_PARMS]);
120 index = parm->index;
121 err = tcf_idr_check_alloc(tn, &index, a, bind);
122 if (err < 0)
123 return err;
124 exists = err;
125 if (exists && bind)
126 return 0;
127
128 switch (parm->eaction) {
129 case TCA_EGRESS_MIRROR:
130 case TCA_EGRESS_REDIR:
131 case TCA_INGRESS_REDIR:
132 case TCA_INGRESS_MIRROR:
133 break;
134 default:
135 if (exists)
136 tcf_idr_release(*a, bind);
137 else
138 tcf_idr_cleanup(tn, index);
139 NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
140 return -EINVAL;
141 }
142
143 if (!exists) {
144 if (!parm->ifindex) {
145 tcf_idr_cleanup(tn, index);
146 NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
147 return -EINVAL;
148 }
149 ret = tcf_idr_create_from_flags(tn, index, est, a,
150 &act_mirred_ops, bind, flags);
151 if (ret) {
152 tcf_idr_cleanup(tn, index);
153 return ret;
154 }
155 ret = ACT_P_CREATED;
156 } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
157 tcf_idr_release(*a, bind);
158 return -EEXIST;
159 }
160
161 m = to_mirred(*a);
162 if (ret == ACT_P_CREATED)
163 INIT_LIST_HEAD(&m->tcfm_list);
164
165 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
166 if (err < 0)
167 goto release_idr;
168
169 spin_lock_bh(&m->tcf_lock);
170
171 if (parm->ifindex) {
172 struct net_device *odev, *ndev;
173
174 ndev = dev_get_by_index(net, parm->ifindex);
175 if (!ndev) {
176 spin_unlock_bh(&m->tcf_lock);
177 err = -ENODEV;
178 goto put_chain;
179 }
180 mac_header_xmit = dev_is_mac_header_xmit(ndev);
181 odev = rcu_replace_pointer(m->tcfm_dev, ndev,
182 lockdep_is_held(&m->tcf_lock));
183 netdev_put(odev, &m->tcfm_dev_tracker);
184 netdev_tracker_alloc(ndev, &m->tcfm_dev_tracker, GFP_ATOMIC);
185 m->tcfm_mac_header_xmit = mac_header_xmit;
186 }
187 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
188 m->tcfm_eaction = parm->eaction;
189 spin_unlock_bh(&m->tcf_lock);
190 if (goto_ch)
191 tcf_chain_put_by_act(goto_ch);
192
193 if (ret == ACT_P_CREATED) {
194 spin_lock(&mirred_list_lock);
195 list_add(&m->tcfm_list, &mirred_list);
196 spin_unlock(&mirred_list_lock);
197 }
198
199 return ret;
200 put_chain:
201 if (goto_ch)
202 tcf_chain_put_by_act(goto_ch);
203 release_idr:
204 tcf_idr_release(*a, bind);
205 return err;
206 }
207
tcf_mirred_forward(bool want_ingress,struct sk_buff * skb)208 static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb)
209 {
210 int err;
211
212 if (!want_ingress)
213 err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
214 else
215 err = netif_receive_skb(skb);
216
217 return err;
218 }
219
tcf_mirred_act(struct sk_buff * skb,const struct tc_action * a,struct tcf_result * res)220 static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
221 struct tcf_result *res)
222 {
223 struct tcf_mirred *m = to_mirred(a);
224 struct sk_buff *skb2 = skb;
225 bool m_mac_header_xmit;
226 struct net_device *dev;
227 unsigned int rec_level;
228 int retval, err = 0;
229 bool use_reinsert;
230 bool want_ingress;
231 bool is_redirect;
232 bool expects_nh;
233 bool at_ingress;
234 int m_eaction;
235 int mac_len;
236 bool at_nh;
237
238 rec_level = __this_cpu_inc_return(mirred_rec_level);
239 if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) {
240 net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
241 netdev_name(skb->dev));
242 __this_cpu_dec(mirred_rec_level);
243 return TC_ACT_SHOT;
244 }
245
246 tcf_lastuse_update(&m->tcf_tm);
247 tcf_action_update_bstats(&m->common, skb);
248
249 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
250 m_eaction = READ_ONCE(m->tcfm_eaction);
251 retval = READ_ONCE(m->tcf_action);
252 dev = rcu_dereference_bh(m->tcfm_dev);
253 if (unlikely(!dev)) {
254 pr_notice_once("tc mirred: target device is gone\n");
255 goto out;
256 }
257
258 if (unlikely(!(dev->flags & IFF_UP))) {
259 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
260 dev->name);
261 goto out;
262 }
263
264 /* we could easily avoid the clone only if called by ingress and clsact;
265 * since we can't easily detect the clsact caller, skip clone only for
266 * ingress - that covers the TC S/W datapath.
267 */
268 is_redirect = tcf_mirred_is_act_redirect(m_eaction);
269 at_ingress = skb_at_tc_ingress(skb);
270 use_reinsert = at_ingress && is_redirect &&
271 tcf_mirred_can_reinsert(retval);
272 if (!use_reinsert) {
273 skb2 = skb_clone(skb, GFP_ATOMIC);
274 if (!skb2)
275 goto out;
276 }
277
278 want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
279
280 /* All mirred/redirected skbs should clear previous ct info */
281 nf_reset_ct(skb2);
282 if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */
283 skb_dst_drop(skb2);
284
285 expects_nh = want_ingress || !m_mac_header_xmit;
286 at_nh = skb->data == skb_network_header(skb);
287 if (at_nh != expects_nh) {
288 mac_len = skb_at_tc_ingress(skb) ? skb->mac_len :
289 skb_network_header(skb) - skb_mac_header(skb);
290 if (expects_nh) {
291 /* target device/action expect data at nh */
292 skb_pull_rcsum(skb2, mac_len);
293 } else {
294 /* target device/action expect data at mac */
295 skb_push_rcsum(skb2, mac_len);
296 }
297 }
298
299 skb2->skb_iif = skb->dev->ifindex;
300 skb2->dev = dev;
301
302 /* mirror is always swallowed */
303 if (is_redirect) {
304 skb_set_redirected(skb2, skb2->tc_at_ingress);
305
306 /* let's the caller reinsert the packet, if possible */
307 if (use_reinsert) {
308 err = tcf_mirred_forward(want_ingress, skb);
309 if (err)
310 tcf_action_inc_overlimit_qstats(&m->common);
311 __this_cpu_dec(mirred_rec_level);
312 return TC_ACT_CONSUMED;
313 }
314 }
315
316 err = tcf_mirred_forward(want_ingress, skb2);
317 if (err) {
318 out:
319 tcf_action_inc_overlimit_qstats(&m->common);
320 if (tcf_mirred_is_act_redirect(m_eaction))
321 retval = TC_ACT_SHOT;
322 }
323 __this_cpu_dec(mirred_rec_level);
324
325 return retval;
326 }
327
tcf_stats_update(struct tc_action * a,u64 bytes,u64 packets,u64 drops,u64 lastuse,bool hw)328 static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets,
329 u64 drops, u64 lastuse, bool hw)
330 {
331 struct tcf_mirred *m = to_mirred(a);
332 struct tcf_t *tm = &m->tcf_tm;
333
334 tcf_action_update_stats(a, bytes, packets, drops, hw);
335 tm->lastuse = max_t(u64, tm->lastuse, lastuse);
336 }
337
tcf_mirred_dump(struct sk_buff * skb,struct tc_action * a,int bind,int ref)338 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
339 int ref)
340 {
341 unsigned char *b = skb_tail_pointer(skb);
342 struct tcf_mirred *m = to_mirred(a);
343 struct tc_mirred opt = {
344 .index = m->tcf_index,
345 .refcnt = refcount_read(&m->tcf_refcnt) - ref,
346 .bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
347 };
348 struct net_device *dev;
349 struct tcf_t t;
350
351 spin_lock_bh(&m->tcf_lock);
352 opt.action = m->tcf_action;
353 opt.eaction = m->tcfm_eaction;
354 dev = tcf_mirred_dev_dereference(m);
355 if (dev)
356 opt.ifindex = dev->ifindex;
357
358 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
359 goto nla_put_failure;
360
361 tcf_tm_dump(&t, &m->tcf_tm);
362 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
363 goto nla_put_failure;
364 spin_unlock_bh(&m->tcf_lock);
365
366 return skb->len;
367
368 nla_put_failure:
369 spin_unlock_bh(&m->tcf_lock);
370 nlmsg_trim(skb, b);
371 return -1;
372 }
373
mirred_device_event(struct notifier_block * unused,unsigned long event,void * ptr)374 static int mirred_device_event(struct notifier_block *unused,
375 unsigned long event, void *ptr)
376 {
377 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
378 struct tcf_mirred *m;
379
380 ASSERT_RTNL();
381 if (event == NETDEV_UNREGISTER) {
382 spin_lock(&mirred_list_lock);
383 list_for_each_entry(m, &mirred_list, tcfm_list) {
384 spin_lock_bh(&m->tcf_lock);
385 if (tcf_mirred_dev_dereference(m) == dev) {
386 netdev_put(dev, &m->tcfm_dev_tracker);
387 /* Note : no rcu grace period necessary, as
388 * net_device are already rcu protected.
389 */
390 RCU_INIT_POINTER(m->tcfm_dev, NULL);
391 }
392 spin_unlock_bh(&m->tcf_lock);
393 }
394 spin_unlock(&mirred_list_lock);
395 }
396
397 return NOTIFY_DONE;
398 }
399
400 static struct notifier_block mirred_device_notifier = {
401 .notifier_call = mirred_device_event,
402 };
403
tcf_mirred_dev_put(void * priv)404 static void tcf_mirred_dev_put(void *priv)
405 {
406 struct net_device *dev = priv;
407
408 dev_put(dev);
409 }
410
411 static struct net_device *
tcf_mirred_get_dev(const struct tc_action * a,tc_action_priv_destructor * destructor)412 tcf_mirred_get_dev(const struct tc_action *a,
413 tc_action_priv_destructor *destructor)
414 {
415 struct tcf_mirred *m = to_mirred(a);
416 struct net_device *dev;
417
418 rcu_read_lock();
419 dev = rcu_dereference(m->tcfm_dev);
420 if (dev) {
421 dev_hold(dev);
422 *destructor = tcf_mirred_dev_put;
423 }
424 rcu_read_unlock();
425
426 return dev;
427 }
428
tcf_mirred_get_fill_size(const struct tc_action * act)429 static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
430 {
431 return nla_total_size(sizeof(struct tc_mirred));
432 }
433
tcf_offload_mirred_get_dev(struct flow_action_entry * entry,const struct tc_action * act)434 static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry,
435 const struct tc_action *act)
436 {
437 entry->dev = act->ops->get_dev(act, &entry->destructor);
438 if (!entry->dev)
439 return;
440 entry->destructor_priv = entry->dev;
441 }
442
tcf_mirred_offload_act_setup(struct tc_action * act,void * entry_data,u32 * index_inc,bool bind,struct netlink_ext_ack * extack)443 static int tcf_mirred_offload_act_setup(struct tc_action *act, void *entry_data,
444 u32 *index_inc, bool bind,
445 struct netlink_ext_ack *extack)
446 {
447 if (bind) {
448 struct flow_action_entry *entry = entry_data;
449
450 if (is_tcf_mirred_egress_redirect(act)) {
451 entry->id = FLOW_ACTION_REDIRECT;
452 tcf_offload_mirred_get_dev(entry, act);
453 } else if (is_tcf_mirred_egress_mirror(act)) {
454 entry->id = FLOW_ACTION_MIRRED;
455 tcf_offload_mirred_get_dev(entry, act);
456 } else if (is_tcf_mirred_ingress_redirect(act)) {
457 entry->id = FLOW_ACTION_REDIRECT_INGRESS;
458 tcf_offload_mirred_get_dev(entry, act);
459 } else if (is_tcf_mirred_ingress_mirror(act)) {
460 entry->id = FLOW_ACTION_MIRRED_INGRESS;
461 tcf_offload_mirred_get_dev(entry, act);
462 } else {
463 NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload");
464 return -EOPNOTSUPP;
465 }
466 *index_inc = 1;
467 } else {
468 struct flow_offload_action *fl_action = entry_data;
469
470 if (is_tcf_mirred_egress_redirect(act))
471 fl_action->id = FLOW_ACTION_REDIRECT;
472 else if (is_tcf_mirred_egress_mirror(act))
473 fl_action->id = FLOW_ACTION_MIRRED;
474 else if (is_tcf_mirred_ingress_redirect(act))
475 fl_action->id = FLOW_ACTION_REDIRECT_INGRESS;
476 else if (is_tcf_mirred_ingress_mirror(act))
477 fl_action->id = FLOW_ACTION_MIRRED_INGRESS;
478 else
479 return -EOPNOTSUPP;
480 }
481
482 return 0;
483 }
484
485 static struct tc_action_ops act_mirred_ops = {
486 .kind = "mirred",
487 .id = TCA_ID_MIRRED,
488 .owner = THIS_MODULE,
489 .act = tcf_mirred_act,
490 .stats_update = tcf_stats_update,
491 .dump = tcf_mirred_dump,
492 .cleanup = tcf_mirred_release,
493 .init = tcf_mirred_init,
494 .get_fill_size = tcf_mirred_get_fill_size,
495 .offload_act_setup = tcf_mirred_offload_act_setup,
496 .size = sizeof(struct tcf_mirred),
497 .get_dev = tcf_mirred_get_dev,
498 };
499
mirred_init_net(struct net * net)500 static __net_init int mirred_init_net(struct net *net)
501 {
502 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
503
504 return tc_action_net_init(net, tn, &act_mirred_ops);
505 }
506
mirred_exit_net(struct list_head * net_list)507 static void __net_exit mirred_exit_net(struct list_head *net_list)
508 {
509 tc_action_net_exit(net_list, act_mirred_ops.net_id);
510 }
511
512 static struct pernet_operations mirred_net_ops = {
513 .init = mirred_init_net,
514 .exit_batch = mirred_exit_net,
515 .id = &act_mirred_ops.net_id,
516 .size = sizeof(struct tc_action_net),
517 };
518
519 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
520 MODULE_DESCRIPTION("Device Mirror/redirect actions");
521 MODULE_LICENSE("GPL");
522
mirred_init_module(void)523 static int __init mirred_init_module(void)
524 {
525 int err = register_netdevice_notifier(&mirred_device_notifier);
526 if (err)
527 return err;
528
529 pr_info("Mirror/redirect action on\n");
530 err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
531 if (err)
532 unregister_netdevice_notifier(&mirred_device_notifier);
533
534 return err;
535 }
536
mirred_cleanup_module(void)537 static void __exit mirred_cleanup_module(void)
538 {
539 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
540 unregister_netdevice_notifier(&mirred_device_notifier);
541 }
542
543 module_init(mirred_init_module);
544 module_exit(mirred_cleanup_module);
545
