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 #include <net/tc_wrapper.h>
28
29 static LIST_HEAD(mirred_list);
30 static DEFINE_SPINLOCK(mirred_list_lock);
31
32 #define MIRRED_NEST_LIMIT 4
33 static DEFINE_PER_CPU(unsigned int, mirred_nest_level);
34
tcf_mirred_is_act_redirect(int action)35 static bool tcf_mirred_is_act_redirect(int action)
36 {
37 return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR;
38 }
39
tcf_mirred_act_wants_ingress(int action)40 static bool tcf_mirred_act_wants_ingress(int action)
41 {
42 switch (action) {
43 case TCA_EGRESS_REDIR:
44 case TCA_EGRESS_MIRROR:
45 return false;
46 case TCA_INGRESS_REDIR:
47 case TCA_INGRESS_MIRROR:
48 return true;
49 default:
50 BUG();
51 }
52 }
53
tcf_mirred_can_reinsert(int action)54 static bool tcf_mirred_can_reinsert(int action)
55 {
56 switch (action) {
57 case TC_ACT_SHOT:
58 case TC_ACT_STOLEN:
59 case TC_ACT_QUEUED:
60 case TC_ACT_TRAP:
61 return true;
62 }
63 return false;
64 }
65
tcf_mirred_dev_dereference(struct tcf_mirred * m)66 static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m)
67 {
68 return rcu_dereference_protected(m->tcfm_dev,
69 lockdep_is_held(&m->tcf_lock));
70 }
71
tcf_mirred_release(struct tc_action * a)72 static void tcf_mirred_release(struct tc_action *a)
73 {
74 struct tcf_mirred *m = to_mirred(a);
75 struct net_device *dev;
76
77 spin_lock(&mirred_list_lock);
78 list_del(&m->tcfm_list);
79 spin_unlock(&mirred_list_lock);
80
81 /* last reference to action, no need to lock */
82 dev = rcu_dereference_protected(m->tcfm_dev, 1);
83 netdev_put(dev, &m->tcfm_dev_tracker);
84 }
85
86 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
87 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
88 };
89
90 static struct tc_action_ops act_mirred_ops;
91
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)92 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
93 struct nlattr *est, struct tc_action **a,
94 struct tcf_proto *tp,
95 u32 flags, struct netlink_ext_ack *extack)
96 {
97 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
98 bool bind = flags & TCA_ACT_FLAGS_BIND;
99 struct nlattr *tb[TCA_MIRRED_MAX + 1];
100 struct tcf_chain *goto_ch = NULL;
101 bool mac_header_xmit = false;
102 struct tc_mirred *parm;
103 struct tcf_mirred *m;
104 bool exists = false;
105 int ret, err;
106 u32 index;
107
108 if (!nla) {
109 NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
110 return -EINVAL;
111 }
112 ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla,
113 mirred_policy, extack);
114 if (ret < 0)
115 return ret;
116 if (!tb[TCA_MIRRED_PARMS]) {
117 NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
118 return -EINVAL;
119 }
120 parm = nla_data(tb[TCA_MIRRED_PARMS]);
121 index = parm->index;
122 err = tcf_idr_check_alloc(tn, &index, a, bind);
123 if (err < 0)
124 return err;
125 exists = err;
126 if (exists && bind)
127 return 0;
128
129 switch (parm->eaction) {
130 case TCA_EGRESS_MIRROR:
131 case TCA_EGRESS_REDIR:
132 case TCA_INGRESS_REDIR:
133 case TCA_INGRESS_MIRROR:
134 break;
135 default:
136 if (exists)
137 tcf_idr_release(*a, bind);
138 else
139 tcf_idr_cleanup(tn, index);
140 NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
141 return -EINVAL;
142 }
143
144 if (!exists) {
145 if (!parm->ifindex) {
146 tcf_idr_cleanup(tn, index);
147 NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
148 return -EINVAL;
149 }
150 ret = tcf_idr_create_from_flags(tn, index, est, a,
151 &act_mirred_ops, bind, flags);
152 if (ret) {
153 tcf_idr_cleanup(tn, index);
154 return ret;
155 }
156 ret = ACT_P_CREATED;
157 } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
158 tcf_idr_release(*a, bind);
159 return -EEXIST;
160 }
161
162 m = to_mirred(*a);
163 if (ret == ACT_P_CREATED)
164 INIT_LIST_HEAD(&m->tcfm_list);
165
166 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
167 if (err < 0)
168 goto release_idr;
169
170 spin_lock_bh(&m->tcf_lock);
171
172 if (parm->ifindex) {
173 struct net_device *odev, *ndev;
174
175 ndev = dev_get_by_index(net, parm->ifindex);
176 if (!ndev) {
177 spin_unlock_bh(&m->tcf_lock);
178 err = -ENODEV;
179 goto put_chain;
180 }
181 mac_header_xmit = dev_is_mac_header_xmit(ndev);
182 odev = rcu_replace_pointer(m->tcfm_dev, ndev,
183 lockdep_is_held(&m->tcf_lock));
184 netdev_put(odev, &m->tcfm_dev_tracker);
185 netdev_tracker_alloc(ndev, &m->tcfm_dev_tracker, GFP_ATOMIC);
186 m->tcfm_mac_header_xmit = mac_header_xmit;
187 }
188 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
189 m->tcfm_eaction = parm->eaction;
190 spin_unlock_bh(&m->tcf_lock);
191 if (goto_ch)
192 tcf_chain_put_by_act(goto_ch);
193
194 if (ret == ACT_P_CREATED) {
195 spin_lock(&mirred_list_lock);
196 list_add(&m->tcfm_list, &mirred_list);
197 spin_unlock(&mirred_list_lock);
198 }
199
200 return ret;
201 put_chain:
202 if (goto_ch)
203 tcf_chain_put_by_act(goto_ch);
204 release_idr:
205 tcf_idr_release(*a, bind);
206 return err;
207 }
208
209 static int
tcf_mirred_forward(bool at_ingress,bool want_ingress,struct sk_buff * skb)210 tcf_mirred_forward(bool at_ingress, bool want_ingress, struct sk_buff *skb)
211 {
212 int err;
213
214 if (!want_ingress)
215 err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
216 else if (!at_ingress)
217 err = netif_rx(skb);
218 else
219 err = netif_receive_skb(skb);
220
221 return err;
222 }
223
tcf_mirred_to_dev(struct sk_buff * skb,struct tcf_mirred * m,struct net_device * dev,const bool m_mac_header_xmit,int m_eaction,int retval)224 static int tcf_mirred_to_dev(struct sk_buff *skb, struct tcf_mirred *m,
225 struct net_device *dev,
226 const bool m_mac_header_xmit, int m_eaction,
227 int retval)
228 {
229 struct sk_buff *skb_to_send = skb;
230 bool want_ingress;
231 bool is_redirect;
232 bool expects_nh;
233 bool at_ingress;
234 bool dont_clone;
235 int mac_len;
236 bool at_nh;
237 int err;
238
239 is_redirect = tcf_mirred_is_act_redirect(m_eaction);
240 if (unlikely(!(dev->flags & IFF_UP)) || !netif_carrier_ok(dev)) {
241 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
242 dev->name);
243 goto err_cant_do;
244 }
245
246 /* we could easily avoid the clone only if called by ingress and clsact;
247 * since we can't easily detect the clsact caller, skip clone only for
248 * ingress - that covers the TC S/W datapath.
249 */
250 at_ingress = skb_at_tc_ingress(skb);
251 dont_clone = skb_at_tc_ingress(skb) && is_redirect &&
252 tcf_mirred_can_reinsert(retval);
253 if (!dont_clone) {
254 skb_to_send = skb_clone(skb, GFP_ATOMIC);
255 if (!skb_to_send)
256 goto err_cant_do;
257 }
258
259 want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
260
261 /* All mirred/redirected skbs should clear previous ct info */
262 nf_reset_ct(skb_to_send);
263 if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */
264 skb_dst_drop(skb_to_send);
265
266 expects_nh = want_ingress || !m_mac_header_xmit;
267 at_nh = skb->data == skb_network_header(skb);
268 if (at_nh != expects_nh) {
269 mac_len = at_ingress ? skb->mac_len :
270 skb_network_offset(skb);
271 if (expects_nh) {
272 /* target device/action expect data at nh */
273 skb_pull_rcsum(skb_to_send, mac_len);
274 } else {
275 /* target device/action expect data at mac */
276 skb_push_rcsum(skb_to_send, mac_len);
277 }
278 }
279
280 skb_to_send->skb_iif = skb->dev->ifindex;
281 skb_to_send->dev = dev;
282
283 if (is_redirect) {
284 if (skb == skb_to_send)
285 retval = TC_ACT_CONSUMED;
286
287 skb_set_redirected(skb_to_send, skb_to_send->tc_at_ingress);
288
289 err = tcf_mirred_forward(at_ingress, want_ingress, skb_to_send);
290 } else {
291 err = tcf_mirred_forward(at_ingress, want_ingress, skb_to_send);
292 }
293 if (err)
294 tcf_action_inc_overlimit_qstats(&m->common);
295
296 return retval;
297
298 err_cant_do:
299 if (is_redirect)
300 retval = TC_ACT_SHOT;
301 tcf_action_inc_overlimit_qstats(&m->common);
302 return retval;
303 }
304
tcf_mirred_act(struct sk_buff * skb,const struct tc_action * a,struct tcf_result * res)305 TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb,
306 const struct tc_action *a,
307 struct tcf_result *res)
308 {
309 struct tcf_mirred *m = to_mirred(a);
310 int retval = READ_ONCE(m->tcf_action);
311 unsigned int nest_level;
312 bool m_mac_header_xmit;
313 struct net_device *dev;
314 int m_eaction;
315
316 nest_level = __this_cpu_inc_return(mirred_nest_level);
317 if (unlikely(nest_level > MIRRED_NEST_LIMIT)) {
318 net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
319 netdev_name(skb->dev));
320 retval = TC_ACT_SHOT;
321 goto dec_nest_level;
322 }
323
324 tcf_lastuse_update(&m->tcf_tm);
325 tcf_action_update_bstats(&m->common, skb);
326
327 dev = rcu_dereference_bh(m->tcfm_dev);
328 if (unlikely(!dev)) {
329 pr_notice_once("tc mirred: target device is gone\n");
330 tcf_action_inc_overlimit_qstats(&m->common);
331 goto dec_nest_level;
332 }
333
334 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
335 m_eaction = READ_ONCE(m->tcfm_eaction);
336
337 retval = tcf_mirred_to_dev(skb, m, dev, m_mac_header_xmit, m_eaction,
338 retval);
339
340 dec_nest_level:
341 __this_cpu_dec(mirred_nest_level);
342
343 return retval;
344 }
345
tcf_stats_update(struct tc_action * a,u64 bytes,u64 packets,u64 drops,u64 lastuse,bool hw)346 static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets,
347 u64 drops, u64 lastuse, bool hw)
348 {
349 struct tcf_mirred *m = to_mirred(a);
350 struct tcf_t *tm = &m->tcf_tm;
351
352 tcf_action_update_stats(a, bytes, packets, drops, hw);
353 tm->lastuse = max_t(u64, tm->lastuse, lastuse);
354 }
355
tcf_mirred_dump(struct sk_buff * skb,struct tc_action * a,int bind,int ref)356 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
357 int ref)
358 {
359 unsigned char *b = skb_tail_pointer(skb);
360 struct tcf_mirred *m = to_mirred(a);
361 struct tc_mirred opt = {
362 .index = m->tcf_index,
363 .refcnt = refcount_read(&m->tcf_refcnt) - ref,
364 .bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
365 };
366 struct net_device *dev;
367 struct tcf_t t;
368
369 spin_lock_bh(&m->tcf_lock);
370 opt.action = m->tcf_action;
371 opt.eaction = m->tcfm_eaction;
372 dev = tcf_mirred_dev_dereference(m);
373 if (dev)
374 opt.ifindex = dev->ifindex;
375
376 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
377 goto nla_put_failure;
378
379 tcf_tm_dump(&t, &m->tcf_tm);
380 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
381 goto nla_put_failure;
382 spin_unlock_bh(&m->tcf_lock);
383
384 return skb->len;
385
386 nla_put_failure:
387 spin_unlock_bh(&m->tcf_lock);
388 nlmsg_trim(skb, b);
389 return -1;
390 }
391
mirred_device_event(struct notifier_block * unused,unsigned long event,void * ptr)392 static int mirred_device_event(struct notifier_block *unused,
393 unsigned long event, void *ptr)
394 {
395 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
396 struct tcf_mirred *m;
397
398 ASSERT_RTNL();
399 if (event == NETDEV_UNREGISTER) {
400 spin_lock(&mirred_list_lock);
401 list_for_each_entry(m, &mirred_list, tcfm_list) {
402 spin_lock_bh(&m->tcf_lock);
403 if (tcf_mirred_dev_dereference(m) == dev) {
404 netdev_put(dev, &m->tcfm_dev_tracker);
405 /* Note : no rcu grace period necessary, as
406 * net_device are already rcu protected.
407 */
408 RCU_INIT_POINTER(m->tcfm_dev, NULL);
409 }
410 spin_unlock_bh(&m->tcf_lock);
411 }
412 spin_unlock(&mirred_list_lock);
413 }
414
415 return NOTIFY_DONE;
416 }
417
418 static struct notifier_block mirred_device_notifier = {
419 .notifier_call = mirred_device_event,
420 };
421
tcf_mirred_dev_put(void * priv)422 static void tcf_mirred_dev_put(void *priv)
423 {
424 struct net_device *dev = priv;
425
426 dev_put(dev);
427 }
428
429 static struct net_device *
tcf_mirred_get_dev(const struct tc_action * a,tc_action_priv_destructor * destructor)430 tcf_mirred_get_dev(const struct tc_action *a,
431 tc_action_priv_destructor *destructor)
432 {
433 struct tcf_mirred *m = to_mirred(a);
434 struct net_device *dev;
435
436 rcu_read_lock();
437 dev = rcu_dereference(m->tcfm_dev);
438 if (dev) {
439 dev_hold(dev);
440 *destructor = tcf_mirred_dev_put;
441 }
442 rcu_read_unlock();
443
444 return dev;
445 }
446
tcf_mirred_get_fill_size(const struct tc_action * act)447 static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
448 {
449 return nla_total_size(sizeof(struct tc_mirred));
450 }
451
tcf_offload_mirred_get_dev(struct flow_action_entry * entry,const struct tc_action * act)452 static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry,
453 const struct tc_action *act)
454 {
455 entry->dev = act->ops->get_dev(act, &entry->destructor);
456 if (!entry->dev)
457 return;
458 entry->destructor_priv = entry->dev;
459 }
460
tcf_mirred_offload_act_setup(struct tc_action * act,void * entry_data,u32 * index_inc,bool bind,struct netlink_ext_ack * extack)461 static int tcf_mirred_offload_act_setup(struct tc_action *act, void *entry_data,
462 u32 *index_inc, bool bind,
463 struct netlink_ext_ack *extack)
464 {
465 if (bind) {
466 struct flow_action_entry *entry = entry_data;
467
468 if (is_tcf_mirred_egress_redirect(act)) {
469 entry->id = FLOW_ACTION_REDIRECT;
470 tcf_offload_mirred_get_dev(entry, act);
471 } else if (is_tcf_mirred_egress_mirror(act)) {
472 entry->id = FLOW_ACTION_MIRRED;
473 tcf_offload_mirred_get_dev(entry, act);
474 } else if (is_tcf_mirred_ingress_redirect(act)) {
475 entry->id = FLOW_ACTION_REDIRECT_INGRESS;
476 tcf_offload_mirred_get_dev(entry, act);
477 } else if (is_tcf_mirred_ingress_mirror(act)) {
478 entry->id = FLOW_ACTION_MIRRED_INGRESS;
479 tcf_offload_mirred_get_dev(entry, act);
480 } else {
481 NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload");
482 return -EOPNOTSUPP;
483 }
484 *index_inc = 1;
485 } else {
486 struct flow_offload_action *fl_action = entry_data;
487
488 if (is_tcf_mirred_egress_redirect(act))
489 fl_action->id = FLOW_ACTION_REDIRECT;
490 else if (is_tcf_mirred_egress_mirror(act))
491 fl_action->id = FLOW_ACTION_MIRRED;
492 else if (is_tcf_mirred_ingress_redirect(act))
493 fl_action->id = FLOW_ACTION_REDIRECT_INGRESS;
494 else if (is_tcf_mirred_ingress_mirror(act))
495 fl_action->id = FLOW_ACTION_MIRRED_INGRESS;
496 else
497 return -EOPNOTSUPP;
498 }
499
500 return 0;
501 }
502
503 static struct tc_action_ops act_mirred_ops = {
504 .kind = "mirred",
505 .id = TCA_ID_MIRRED,
506 .owner = THIS_MODULE,
507 .act = tcf_mirred_act,
508 .stats_update = tcf_stats_update,
509 .dump = tcf_mirred_dump,
510 .cleanup = tcf_mirred_release,
511 .init = tcf_mirred_init,
512 .get_fill_size = tcf_mirred_get_fill_size,
513 .offload_act_setup = tcf_mirred_offload_act_setup,
514 .size = sizeof(struct tcf_mirred),
515 .get_dev = tcf_mirred_get_dev,
516 };
517
mirred_init_net(struct net * net)518 static __net_init int mirred_init_net(struct net *net)
519 {
520 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
521
522 return tc_action_net_init(net, tn, &act_mirred_ops);
523 }
524
mirred_exit_net(struct list_head * net_list)525 static void __net_exit mirred_exit_net(struct list_head *net_list)
526 {
527 tc_action_net_exit(net_list, act_mirred_ops.net_id);
528 }
529
530 static struct pernet_operations mirred_net_ops = {
531 .init = mirred_init_net,
532 .exit_batch = mirred_exit_net,
533 .id = &act_mirred_ops.net_id,
534 .size = sizeof(struct tc_action_net),
535 };
536
537 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
538 MODULE_DESCRIPTION("Device Mirror/redirect actions");
539 MODULE_LICENSE("GPL");
540
mirred_init_module(void)541 static int __init mirred_init_module(void)
542 {
543 int err = register_netdevice_notifier(&mirred_device_notifier);
544 if (err)
545 return err;
546
547 pr_info("Mirror/redirect action on\n");
548 err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
549 if (err)
550 unregister_netdevice_notifier(&mirred_device_notifier);
551
552 return err;
553 }
554
mirred_cleanup_module(void)555 static void __exit mirred_cleanup_module(void)
556 {
557 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
558 unregister_netdevice_notifier(&mirred_device_notifier);
559 }
560
561 module_init(mirred_init_module);
562 module_exit(mirred_cleanup_module);
563