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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
29static LIST_HEAD(mirred_list);
30static DEFINE_SPINLOCK(mirred_list_lock);
31
32#define MIRRED_NEST_LIMIT 4
33static DEFINE_PER_CPU(unsigned int, mirred_nest_level);
34
35static bool tcf_mirred_is_act_redirect(int action)
36{
37 return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR;
38}
39
40static 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
54static 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
66static 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
72static 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
86static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
87 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
88 [TCA_MIRRED_BLOCKID] = NLA_POLICY_MIN(NLA_U32, 1),
89};
90
91static struct tc_action_ops act_mirred_ops;
92
93static void tcf_mirred_replace_dev(struct tcf_mirred *m,
94 struct net_device *ndev)
95{
96 struct net_device *odev;
97
98 odev = rcu_replace_pointer(m->tcfm_dev, ndev,
99 lockdep_is_held(&m->tcf_lock));
100 netdev_put(odev, &m->tcfm_dev_tracker);
101}
102
103static int tcf_mirred_init(struct net *net, struct nlattr *nla,
104 struct nlattr *est, struct tc_action **a,
105 struct tcf_proto *tp,
106 u32 flags, struct netlink_ext_ack *extack)
107{
108 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
109 bool bind = flags & TCA_ACT_FLAGS_BIND;
110 struct nlattr *tb[TCA_MIRRED_MAX + 1];
111 struct tcf_chain *goto_ch = NULL;
112 bool mac_header_xmit = false;
113 struct tc_mirred *parm;
114 struct tcf_mirred *m;
115 bool exists = false;
116 int ret, err;
117 u32 index;
118
119 if (!nla) {
120 NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
121 return -EINVAL;
122 }
123 ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla,
124 mirred_policy, extack);
125 if (ret < 0)
126 return ret;
127 if (!tb[TCA_MIRRED_PARMS]) {
128 NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
129 return -EINVAL;
130 }
131 parm = nla_data(tb[TCA_MIRRED_PARMS]);
132 index = parm->index;
133 err = tcf_idr_check_alloc(tn, &index, a, bind);
134 if (err < 0)
135 return err;
136 exists = err;
137 if (exists && bind)
138 return ACT_P_BOUND;
139
140 if (tb[TCA_MIRRED_BLOCKID] && parm->ifindex) {
141 NL_SET_ERR_MSG_MOD(extack,
142 "Cannot specify Block ID and dev simultaneously");
143 if (exists)
144 tcf_idr_release(*a, bind);
145 else
146 tcf_idr_cleanup(tn, index);
147
148 return -EINVAL;
149 }
150
151 switch (parm->eaction) {
152 case TCA_EGRESS_MIRROR:
153 case TCA_EGRESS_REDIR:
154 case TCA_INGRESS_REDIR:
155 case TCA_INGRESS_MIRROR:
156 break;
157 default:
158 if (exists)
159 tcf_idr_release(*a, bind);
160 else
161 tcf_idr_cleanup(tn, index);
162 NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
163 return -EINVAL;
164 }
165
166 if (!exists) {
167 if (!parm->ifindex && !tb[TCA_MIRRED_BLOCKID]) {
168 tcf_idr_cleanup(tn, index);
169 NL_SET_ERR_MSG_MOD(extack,
170 "Must specify device or block");
171 return -EINVAL;
172 }
173 ret = tcf_idr_create_from_flags(tn, index, est, a,
174 &act_mirred_ops, bind, flags);
175 if (ret) {
176 tcf_idr_cleanup(tn, index);
177 return ret;
178 }
179 ret = ACT_P_CREATED;
180 } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
181 tcf_idr_release(*a, bind);
182 return -EEXIST;
183 }
184
185 m = to_mirred(*a);
186 if (ret == ACT_P_CREATED)
187 INIT_LIST_HEAD(&m->tcfm_list);
188
189 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
190 if (err < 0)
191 goto release_idr;
192
193 spin_lock_bh(&m->tcf_lock);
194
195 if (parm->ifindex) {
196 struct net_device *ndev;
197
198 ndev = dev_get_by_index(net, parm->ifindex);
199 if (!ndev) {
200 spin_unlock_bh(&m->tcf_lock);
201 err = -ENODEV;
202 goto put_chain;
203 }
204 mac_header_xmit = dev_is_mac_header_xmit(ndev);
205 tcf_mirred_replace_dev(m, ndev);
206 netdev_tracker_alloc(ndev, &m->tcfm_dev_tracker, GFP_ATOMIC);
207 m->tcfm_mac_header_xmit = mac_header_xmit;
208 m->tcfm_blockid = 0;
209 } else if (tb[TCA_MIRRED_BLOCKID]) {
210 tcf_mirred_replace_dev(m, NULL);
211 m->tcfm_mac_header_xmit = false;
212 m->tcfm_blockid = nla_get_u32(tb[TCA_MIRRED_BLOCKID]);
213 }
214 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
215 m->tcfm_eaction = parm->eaction;
216 spin_unlock_bh(&m->tcf_lock);
217 if (goto_ch)
218 tcf_chain_put_by_act(goto_ch);
219
220 if (ret == ACT_P_CREATED) {
221 spin_lock(&mirred_list_lock);
222 list_add(&m->tcfm_list, &mirred_list);
223 spin_unlock(&mirred_list_lock);
224 }
225
226 return ret;
227put_chain:
228 if (goto_ch)
229 tcf_chain_put_by_act(goto_ch);
230release_idr:
231 tcf_idr_release(*a, bind);
232 return err;
233}
234
235static int
236tcf_mirred_forward(bool at_ingress, bool want_ingress, struct sk_buff *skb)
237{
238 int err;
239
240 if (!want_ingress)
241 err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
242 else if (!at_ingress)
243 err = netif_rx(skb);
244 else
245 err = netif_receive_skb(skb);
246
247 return err;
248}
249
250static int tcf_mirred_to_dev(struct sk_buff *skb, struct tcf_mirred *m,
251 struct net_device *dev,
252 const bool m_mac_header_xmit, int m_eaction,
253 int retval)
254{
255 struct sk_buff *skb_to_send = skb;
256 bool want_ingress;
257 bool is_redirect;
258 bool expects_nh;
259 bool at_ingress;
260 bool dont_clone;
261 int mac_len;
262 bool at_nh;
263 int err;
264
265 is_redirect = tcf_mirred_is_act_redirect(m_eaction);
266 if (unlikely(!(dev->flags & IFF_UP)) || !netif_carrier_ok(dev)) {
267 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
268 dev->name);
269 goto err_cant_do;
270 }
271
272 /* we could easily avoid the clone only if called by ingress and clsact;
273 * since we can't easily detect the clsact caller, skip clone only for
274 * ingress - that covers the TC S/W datapath.
275 */
276 at_ingress = skb_at_tc_ingress(skb);
277 dont_clone = skb_at_tc_ingress(skb) && is_redirect &&
278 tcf_mirred_can_reinsert(retval);
279 if (!dont_clone) {
280 skb_to_send = skb_clone(skb, GFP_ATOMIC);
281 if (!skb_to_send)
282 goto err_cant_do;
283 }
284
285 want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
286
287 /* All mirred/redirected skbs should clear previous ct info */
288 nf_reset_ct(skb_to_send);
289 if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */
290 skb_dst_drop(skb_to_send);
291
292 expects_nh = want_ingress || !m_mac_header_xmit;
293 at_nh = skb->data == skb_network_header(skb);
294 if (at_nh != expects_nh) {
295 mac_len = at_ingress ? skb->mac_len :
296 skb_network_offset(skb);
297 if (expects_nh) {
298 /* target device/action expect data at nh */
299 skb_pull_rcsum(skb_to_send, mac_len);
300 } else {
301 /* target device/action expect data at mac */
302 skb_push_rcsum(skb_to_send, mac_len);
303 }
304 }
305
306 skb_to_send->skb_iif = skb->dev->ifindex;
307 skb_to_send->dev = dev;
308
309 if (is_redirect) {
310 if (skb == skb_to_send)
311 retval = TC_ACT_CONSUMED;
312
313 skb_set_redirected(skb_to_send, skb_to_send->tc_at_ingress);
314
315 err = tcf_mirred_forward(at_ingress, want_ingress, skb_to_send);
316 } else {
317 err = tcf_mirred_forward(at_ingress, want_ingress, skb_to_send);
318 }
319 if (err)
320 tcf_action_inc_overlimit_qstats(&m->common);
321
322 return retval;
323
324err_cant_do:
325 if (is_redirect)
326 retval = TC_ACT_SHOT;
327 tcf_action_inc_overlimit_qstats(&m->common);
328 return retval;
329}
330
331static int tcf_blockcast_redir(struct sk_buff *skb, struct tcf_mirred *m,
332 struct tcf_block *block, int m_eaction,
333 const u32 exception_ifindex, int retval)
334{
335 struct net_device *dev_prev = NULL;
336 struct net_device *dev = NULL;
337 unsigned long index;
338 int mirred_eaction;
339
340 mirred_eaction = tcf_mirred_act_wants_ingress(m_eaction) ?
341 TCA_INGRESS_MIRROR : TCA_EGRESS_MIRROR;
342
343 xa_for_each(&block->ports, index, dev) {
344 if (index == exception_ifindex)
345 continue;
346
347 if (!dev_prev)
348 goto assign_prev;
349
350 tcf_mirred_to_dev(skb, m, dev_prev,
351 dev_is_mac_header_xmit(dev),
352 mirred_eaction, retval);
353assign_prev:
354 dev_prev = dev;
355 }
356
357 if (dev_prev)
358 return tcf_mirred_to_dev(skb, m, dev_prev,
359 dev_is_mac_header_xmit(dev_prev),
360 m_eaction, retval);
361
362 return retval;
363}
364
365static int tcf_blockcast_mirror(struct sk_buff *skb, struct tcf_mirred *m,
366 struct tcf_block *block, int m_eaction,
367 const u32 exception_ifindex, int retval)
368{
369 struct net_device *dev = NULL;
370 unsigned long index;
371
372 xa_for_each(&block->ports, index, dev) {
373 if (index == exception_ifindex)
374 continue;
375
376 tcf_mirred_to_dev(skb, m, dev,
377 dev_is_mac_header_xmit(dev),
378 m_eaction, retval);
379 }
380
381 return retval;
382}
383
384static int tcf_blockcast(struct sk_buff *skb, struct tcf_mirred *m,
385 const u32 blockid, struct tcf_result *res,
386 int retval)
387{
388 const u32 exception_ifindex = skb->dev->ifindex;
389 struct tcf_block *block;
390 bool is_redirect;
391 int m_eaction;
392
393 m_eaction = READ_ONCE(m->tcfm_eaction);
394 is_redirect = tcf_mirred_is_act_redirect(m_eaction);
395
396 /* we are already under rcu protection, so can call block lookup
397 * directly.
398 */
399 block = tcf_block_lookup(dev_net(skb->dev), blockid);
400 if (!block || xa_empty(&block->ports)) {
401 tcf_action_inc_overlimit_qstats(&m->common);
402 return retval;
403 }
404
405 if (is_redirect)
406 return tcf_blockcast_redir(skb, m, block, m_eaction,
407 exception_ifindex, retval);
408
409 /* If it's not redirect, it is mirror */
410 return tcf_blockcast_mirror(skb, m, block, m_eaction, exception_ifindex,
411 retval);
412}
413
414TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb,
415 const struct tc_action *a,
416 struct tcf_result *res)
417{
418 struct tcf_mirred *m = to_mirred(a);
419 int retval = READ_ONCE(m->tcf_action);
420 unsigned int nest_level;
421 bool m_mac_header_xmit;
422 struct net_device *dev;
423 int m_eaction;
424 u32 blockid;
425
426 nest_level = __this_cpu_inc_return(mirred_nest_level);
427 if (unlikely(nest_level > MIRRED_NEST_LIMIT)) {
428 net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
429 netdev_name(skb->dev));
430 retval = TC_ACT_SHOT;
431 goto dec_nest_level;
432 }
433
434 tcf_lastuse_update(&m->tcf_tm);
435 tcf_action_update_bstats(&m->common, skb);
436
437 blockid = READ_ONCE(m->tcfm_blockid);
438 if (blockid) {
439 retval = tcf_blockcast(skb, m, blockid, res, retval);
440 goto dec_nest_level;
441 }
442
443 dev = rcu_dereference_bh(m->tcfm_dev);
444 if (unlikely(!dev)) {
445 pr_notice_once("tc mirred: target device is gone\n");
446 tcf_action_inc_overlimit_qstats(&m->common);
447 goto dec_nest_level;
448 }
449
450 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
451 m_eaction = READ_ONCE(m->tcfm_eaction);
452
453 retval = tcf_mirred_to_dev(skb, m, dev, m_mac_header_xmit, m_eaction,
454 retval);
455
456dec_nest_level:
457 __this_cpu_dec(mirred_nest_level);
458
459 return retval;
460}
461
462static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets,
463 u64 drops, u64 lastuse, bool hw)
464{
465 struct tcf_mirred *m = to_mirred(a);
466 struct tcf_t *tm = &m->tcf_tm;
467
468 tcf_action_update_stats(a, bytes, packets, drops, hw);
469 tm->lastuse = max_t(u64, tm->lastuse, lastuse);
470}
471
472static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
473 int ref)
474{
475 unsigned char *b = skb_tail_pointer(skb);
476 struct tcf_mirred *m = to_mirred(a);
477 struct tc_mirred opt = {
478 .index = m->tcf_index,
479 .refcnt = refcount_read(&m->tcf_refcnt) - ref,
480 .bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
481 };
482 struct net_device *dev;
483 struct tcf_t t;
484 u32 blockid;
485
486 spin_lock_bh(&m->tcf_lock);
487 opt.action = m->tcf_action;
488 opt.eaction = m->tcfm_eaction;
489 dev = tcf_mirred_dev_dereference(m);
490 if (dev)
491 opt.ifindex = dev->ifindex;
492
493 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
494 goto nla_put_failure;
495
496 blockid = m->tcfm_blockid;
497 if (blockid && nla_put_u32(skb, TCA_MIRRED_BLOCKID, blockid))
498 goto nla_put_failure;
499
500 tcf_tm_dump(&t, &m->tcf_tm);
501 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
502 goto nla_put_failure;
503 spin_unlock_bh(&m->tcf_lock);
504
505 return skb->len;
506
507nla_put_failure:
508 spin_unlock_bh(&m->tcf_lock);
509 nlmsg_trim(skb, b);
510 return -1;
511}
512
513static int mirred_device_event(struct notifier_block *unused,
514 unsigned long event, void *ptr)
515{
516 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
517 struct tcf_mirred *m;
518
519 ASSERT_RTNL();
520 if (event == NETDEV_UNREGISTER) {
521 spin_lock(&mirred_list_lock);
522 list_for_each_entry(m, &mirred_list, tcfm_list) {
523 spin_lock_bh(&m->tcf_lock);
524 if (tcf_mirred_dev_dereference(m) == dev) {
525 netdev_put(dev, &m->tcfm_dev_tracker);
526 /* Note : no rcu grace period necessary, as
527 * net_device are already rcu protected.
528 */
529 RCU_INIT_POINTER(m->tcfm_dev, NULL);
530 }
531 spin_unlock_bh(&m->tcf_lock);
532 }
533 spin_unlock(&mirred_list_lock);
534 }
535
536 return NOTIFY_DONE;
537}
538
539static struct notifier_block mirred_device_notifier = {
540 .notifier_call = mirred_device_event,
541};
542
543static void tcf_mirred_dev_put(void *priv)
544{
545 struct net_device *dev = priv;
546
547 dev_put(dev);
548}
549
550static struct net_device *
551tcf_mirred_get_dev(const struct tc_action *a,
552 tc_action_priv_destructor *destructor)
553{
554 struct tcf_mirred *m = to_mirred(a);
555 struct net_device *dev;
556
557 rcu_read_lock();
558 dev = rcu_dereference(m->tcfm_dev);
559 if (dev) {
560 dev_hold(dev);
561 *destructor = tcf_mirred_dev_put;
562 }
563 rcu_read_unlock();
564
565 return dev;
566}
567
568static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
569{
570 return nla_total_size(sizeof(struct tc_mirred));
571}
572
573static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry,
574 const struct tc_action *act)
575{
576 entry->dev = act->ops->get_dev(act, &entry->destructor);
577 if (!entry->dev)
578 return;
579 entry->destructor_priv = entry->dev;
580}
581
582static int tcf_mirred_offload_act_setup(struct tc_action *act, void *entry_data,
583 u32 *index_inc, bool bind,
584 struct netlink_ext_ack *extack)
585{
586 if (bind) {
587 struct flow_action_entry *entry = entry_data;
588
589 if (is_tcf_mirred_egress_redirect(act)) {
590 entry->id = FLOW_ACTION_REDIRECT;
591 tcf_offload_mirred_get_dev(entry, act);
592 } else if (is_tcf_mirred_egress_mirror(act)) {
593 entry->id = FLOW_ACTION_MIRRED;
594 tcf_offload_mirred_get_dev(entry, act);
595 } else if (is_tcf_mirred_ingress_redirect(act)) {
596 entry->id = FLOW_ACTION_REDIRECT_INGRESS;
597 tcf_offload_mirred_get_dev(entry, act);
598 } else if (is_tcf_mirred_ingress_mirror(act)) {
599 entry->id = FLOW_ACTION_MIRRED_INGRESS;
600 tcf_offload_mirred_get_dev(entry, act);
601 } else {
602 NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload");
603 return -EOPNOTSUPP;
604 }
605 *index_inc = 1;
606 } else {
607 struct flow_offload_action *fl_action = entry_data;
608
609 if (is_tcf_mirred_egress_redirect(act))
610 fl_action->id = FLOW_ACTION_REDIRECT;
611 else if (is_tcf_mirred_egress_mirror(act))
612 fl_action->id = FLOW_ACTION_MIRRED;
613 else if (is_tcf_mirred_ingress_redirect(act))
614 fl_action->id = FLOW_ACTION_REDIRECT_INGRESS;
615 else if (is_tcf_mirred_ingress_mirror(act))
616 fl_action->id = FLOW_ACTION_MIRRED_INGRESS;
617 else
618 return -EOPNOTSUPP;
619 }
620
621 return 0;
622}
623
624static struct tc_action_ops act_mirred_ops = {
625 .kind = "mirred",
626 .id = TCA_ID_MIRRED,
627 .owner = THIS_MODULE,
628 .act = tcf_mirred_act,
629 .stats_update = tcf_stats_update,
630 .dump = tcf_mirred_dump,
631 .cleanup = tcf_mirred_release,
632 .init = tcf_mirred_init,
633 .get_fill_size = tcf_mirred_get_fill_size,
634 .offload_act_setup = tcf_mirred_offload_act_setup,
635 .size = sizeof(struct tcf_mirred),
636 .get_dev = tcf_mirred_get_dev,
637};
638MODULE_ALIAS_NET_ACT("mirred");
639
640static __net_init int mirred_init_net(struct net *net)
641{
642 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
643
644 return tc_action_net_init(net, tn, &act_mirred_ops);
645}
646
647static void __net_exit mirred_exit_net(struct list_head *net_list)
648{
649 tc_action_net_exit(net_list, act_mirred_ops.net_id);
650}
651
652static struct pernet_operations mirred_net_ops = {
653 .init = mirred_init_net,
654 .exit_batch = mirred_exit_net,
655 .id = &act_mirred_ops.net_id,
656 .size = sizeof(struct tc_action_net),
657};
658
659MODULE_AUTHOR("Jamal Hadi Salim(2002)");
660MODULE_DESCRIPTION("Device Mirror/redirect actions");
661MODULE_LICENSE("GPL");
662
663static int __init mirred_init_module(void)
664{
665 int err = register_netdevice_notifier(&mirred_device_notifier);
666 if (err)
667 return err;
668
669 pr_info("Mirror/redirect action on\n");
670 err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
671 if (err)
672 unregister_netdevice_notifier(&mirred_device_notifier);
673
674 return err;
675}
676
677static void __exit mirred_cleanup_module(void)
678{
679 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
680 unregister_netdevice_notifier(&mirred_device_notifier);
681}
682
683module_init(mirred_init_module);
684module_exit(mirred_cleanup_module);
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
29static LIST_HEAD(mirred_list);
30static DEFINE_SPINLOCK(mirred_list_lock);
31
32#define MIRRED_RECURSION_LIMIT 4
33static DEFINE_PER_CPU(unsigned int, mirred_rec_level);
34
35static bool tcf_mirred_is_act_redirect(int action)
36{
37 return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR;
38}
39
40static 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
54static 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
66static 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
72static 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
86static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
87 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
88};
89
90static struct tc_action_ops act_mirred_ops;
91
92static 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;
201put_chain:
202 if (goto_ch)
203 tcf_chain_put_by_act(goto_ch);
204release_idr:
205 tcf_idr_release(*a, bind);
206 return err;
207}
208
209static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb)
210{
211 int err;
212
213 if (!want_ingress)
214 err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
215 else
216 err = netif_receive_skb(skb);
217
218 return err;
219}
220
221TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb,
222 const struct tc_action *a,
223 struct tcf_result *res)
224{
225 struct tcf_mirred *m = to_mirred(a);
226 struct sk_buff *skb2 = skb;
227 bool m_mac_header_xmit;
228 struct net_device *dev;
229 unsigned int rec_level;
230 int retval, err = 0;
231 bool use_reinsert;
232 bool want_ingress;
233 bool is_redirect;
234 bool expects_nh;
235 bool at_ingress;
236 int m_eaction;
237 int mac_len;
238 bool at_nh;
239
240 rec_level = __this_cpu_inc_return(mirred_rec_level);
241 if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) {
242 net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
243 netdev_name(skb->dev));
244 __this_cpu_dec(mirred_rec_level);
245 return TC_ACT_SHOT;
246 }
247
248 tcf_lastuse_update(&m->tcf_tm);
249 tcf_action_update_bstats(&m->common, skb);
250
251 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
252 m_eaction = READ_ONCE(m->tcfm_eaction);
253 retval = READ_ONCE(m->tcf_action);
254 dev = rcu_dereference_bh(m->tcfm_dev);
255 if (unlikely(!dev)) {
256 pr_notice_once("tc mirred: target device is gone\n");
257 goto out;
258 }
259
260 if (unlikely(!(dev->flags & IFF_UP))) {
261 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
262 dev->name);
263 goto out;
264 }
265
266 /* we could easily avoid the clone only if called by ingress and clsact;
267 * since we can't easily detect the clsact caller, skip clone only for
268 * ingress - that covers the TC S/W datapath.
269 */
270 is_redirect = tcf_mirred_is_act_redirect(m_eaction);
271 at_ingress = skb_at_tc_ingress(skb);
272 use_reinsert = at_ingress && is_redirect &&
273 tcf_mirred_can_reinsert(retval);
274 if (!use_reinsert) {
275 skb2 = skb_clone(skb, GFP_ATOMIC);
276 if (!skb2)
277 goto out;
278 }
279
280 want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
281
282 /* All mirred/redirected skbs should clear previous ct info */
283 nf_reset_ct(skb2);
284 if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */
285 skb_dst_drop(skb2);
286
287 expects_nh = want_ingress || !m_mac_header_xmit;
288 at_nh = skb->data == skb_network_header(skb);
289 if (at_nh != expects_nh) {
290 mac_len = skb_at_tc_ingress(skb) ? skb->mac_len :
291 skb_network_header(skb) - skb_mac_header(skb);
292 if (expects_nh) {
293 /* target device/action expect data at nh */
294 skb_pull_rcsum(skb2, mac_len);
295 } else {
296 /* target device/action expect data at mac */
297 skb_push_rcsum(skb2, mac_len);
298 }
299 }
300
301 skb2->skb_iif = skb->dev->ifindex;
302 skb2->dev = dev;
303
304 /* mirror is always swallowed */
305 if (is_redirect) {
306 skb_set_redirected(skb2, skb2->tc_at_ingress);
307
308 /* let's the caller reinsert the packet, if possible */
309 if (use_reinsert) {
310 err = tcf_mirred_forward(want_ingress, skb);
311 if (err)
312 tcf_action_inc_overlimit_qstats(&m->common);
313 __this_cpu_dec(mirred_rec_level);
314 return TC_ACT_CONSUMED;
315 }
316 }
317
318 err = tcf_mirred_forward(want_ingress, skb2);
319 if (err) {
320out:
321 tcf_action_inc_overlimit_qstats(&m->common);
322 if (tcf_mirred_is_act_redirect(m_eaction))
323 retval = TC_ACT_SHOT;
324 }
325 __this_cpu_dec(mirred_rec_level);
326
327 return retval;
328}
329
330static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets,
331 u64 drops, u64 lastuse, bool hw)
332{
333 struct tcf_mirred *m = to_mirred(a);
334 struct tcf_t *tm = &m->tcf_tm;
335
336 tcf_action_update_stats(a, bytes, packets, drops, hw);
337 tm->lastuse = max_t(u64, tm->lastuse, lastuse);
338}
339
340static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
341 int ref)
342{
343 unsigned char *b = skb_tail_pointer(skb);
344 struct tcf_mirred *m = to_mirred(a);
345 struct tc_mirred opt = {
346 .index = m->tcf_index,
347 .refcnt = refcount_read(&m->tcf_refcnt) - ref,
348 .bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
349 };
350 struct net_device *dev;
351 struct tcf_t t;
352
353 spin_lock_bh(&m->tcf_lock);
354 opt.action = m->tcf_action;
355 opt.eaction = m->tcfm_eaction;
356 dev = tcf_mirred_dev_dereference(m);
357 if (dev)
358 opt.ifindex = dev->ifindex;
359
360 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
361 goto nla_put_failure;
362
363 tcf_tm_dump(&t, &m->tcf_tm);
364 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
365 goto nla_put_failure;
366 spin_unlock_bh(&m->tcf_lock);
367
368 return skb->len;
369
370nla_put_failure:
371 spin_unlock_bh(&m->tcf_lock);
372 nlmsg_trim(skb, b);
373 return -1;
374}
375
376static int mirred_device_event(struct notifier_block *unused,
377 unsigned long event, void *ptr)
378{
379 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
380 struct tcf_mirred *m;
381
382 ASSERT_RTNL();
383 if (event == NETDEV_UNREGISTER) {
384 spin_lock(&mirred_list_lock);
385 list_for_each_entry(m, &mirred_list, tcfm_list) {
386 spin_lock_bh(&m->tcf_lock);
387 if (tcf_mirred_dev_dereference(m) == dev) {
388 netdev_put(dev, &m->tcfm_dev_tracker);
389 /* Note : no rcu grace period necessary, as
390 * net_device are already rcu protected.
391 */
392 RCU_INIT_POINTER(m->tcfm_dev, NULL);
393 }
394 spin_unlock_bh(&m->tcf_lock);
395 }
396 spin_unlock(&mirred_list_lock);
397 }
398
399 return NOTIFY_DONE;
400}
401
402static struct notifier_block mirred_device_notifier = {
403 .notifier_call = mirred_device_event,
404};
405
406static void tcf_mirred_dev_put(void *priv)
407{
408 struct net_device *dev = priv;
409
410 dev_put(dev);
411}
412
413static struct net_device *
414tcf_mirred_get_dev(const struct tc_action *a,
415 tc_action_priv_destructor *destructor)
416{
417 struct tcf_mirred *m = to_mirred(a);
418 struct net_device *dev;
419
420 rcu_read_lock();
421 dev = rcu_dereference(m->tcfm_dev);
422 if (dev) {
423 dev_hold(dev);
424 *destructor = tcf_mirred_dev_put;
425 }
426 rcu_read_unlock();
427
428 return dev;
429}
430
431static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
432{
433 return nla_total_size(sizeof(struct tc_mirred));
434}
435
436static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry,
437 const struct tc_action *act)
438{
439 entry->dev = act->ops->get_dev(act, &entry->destructor);
440 if (!entry->dev)
441 return;
442 entry->destructor_priv = entry->dev;
443}
444
445static int tcf_mirred_offload_act_setup(struct tc_action *act, void *entry_data,
446 u32 *index_inc, bool bind,
447 struct netlink_ext_ack *extack)
448{
449 if (bind) {
450 struct flow_action_entry *entry = entry_data;
451
452 if (is_tcf_mirred_egress_redirect(act)) {
453 entry->id = FLOW_ACTION_REDIRECT;
454 tcf_offload_mirred_get_dev(entry, act);
455 } else if (is_tcf_mirred_egress_mirror(act)) {
456 entry->id = FLOW_ACTION_MIRRED;
457 tcf_offload_mirred_get_dev(entry, act);
458 } else if (is_tcf_mirred_ingress_redirect(act)) {
459 entry->id = FLOW_ACTION_REDIRECT_INGRESS;
460 tcf_offload_mirred_get_dev(entry, act);
461 } else if (is_tcf_mirred_ingress_mirror(act)) {
462 entry->id = FLOW_ACTION_MIRRED_INGRESS;
463 tcf_offload_mirred_get_dev(entry, act);
464 } else {
465 NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload");
466 return -EOPNOTSUPP;
467 }
468 *index_inc = 1;
469 } else {
470 struct flow_offload_action *fl_action = entry_data;
471
472 if (is_tcf_mirred_egress_redirect(act))
473 fl_action->id = FLOW_ACTION_REDIRECT;
474 else if (is_tcf_mirred_egress_mirror(act))
475 fl_action->id = FLOW_ACTION_MIRRED;
476 else if (is_tcf_mirred_ingress_redirect(act))
477 fl_action->id = FLOW_ACTION_REDIRECT_INGRESS;
478 else if (is_tcf_mirred_ingress_mirror(act))
479 fl_action->id = FLOW_ACTION_MIRRED_INGRESS;
480 else
481 return -EOPNOTSUPP;
482 }
483
484 return 0;
485}
486
487static struct tc_action_ops act_mirred_ops = {
488 .kind = "mirred",
489 .id = TCA_ID_MIRRED,
490 .owner = THIS_MODULE,
491 .act = tcf_mirred_act,
492 .stats_update = tcf_stats_update,
493 .dump = tcf_mirred_dump,
494 .cleanup = tcf_mirred_release,
495 .init = tcf_mirred_init,
496 .get_fill_size = tcf_mirred_get_fill_size,
497 .offload_act_setup = tcf_mirred_offload_act_setup,
498 .size = sizeof(struct tcf_mirred),
499 .get_dev = tcf_mirred_get_dev,
500};
501
502static __net_init int mirred_init_net(struct net *net)
503{
504 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
505
506 return tc_action_net_init(net, tn, &act_mirred_ops);
507}
508
509static void __net_exit mirred_exit_net(struct list_head *net_list)
510{
511 tc_action_net_exit(net_list, act_mirred_ops.net_id);
512}
513
514static struct pernet_operations mirred_net_ops = {
515 .init = mirred_init_net,
516 .exit_batch = mirred_exit_net,
517 .id = &act_mirred_ops.net_id,
518 .size = sizeof(struct tc_action_net),
519};
520
521MODULE_AUTHOR("Jamal Hadi Salim(2002)");
522MODULE_DESCRIPTION("Device Mirror/redirect actions");
523MODULE_LICENSE("GPL");
524
525static int __init mirred_init_module(void)
526{
527 int err = register_netdevice_notifier(&mirred_device_notifier);
528 if (err)
529 return err;
530
531 pr_info("Mirror/redirect action on\n");
532 err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
533 if (err)
534 unregister_netdevice_notifier(&mirred_device_notifier);
535
536 return err;
537}
538
539static void __exit mirred_cleanup_module(void)
540{
541 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
542 unregister_netdevice_notifier(&mirred_device_notifier);
543}
544
545module_init(mirred_init_module);
546module_exit(mirred_cleanup_module);