1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * net/sched/act_mirred.c packet mirroring and redirect actions
5 * Authors: Jamal Hadi Salim (2002-4)
7 * TODO: Add ingress support (and socket redirect support)
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>
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>
29 static LIST_HEAD(mirred_list);
30 static DEFINE_SPINLOCK(mirred_list_lock);
32 #define MIRRED_NEST_LIMIT 4
33 static DEFINE_PER_CPU(unsigned int, mirred_nest_level);
35 static bool tcf_mirred_is_act_redirect(int action)
37 return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR;
40 static bool tcf_mirred_act_wants_ingress(int action)
43 case TCA_EGRESS_REDIR:
44 case TCA_EGRESS_MIRROR:
46 case TCA_INGRESS_REDIR:
47 case TCA_INGRESS_MIRROR:
54 static bool tcf_mirred_can_reinsert(int action)
66 static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m)
68 return rcu_dereference_protected(m->tcfm_dev,
69 lockdep_is_held(&m->tcf_lock));
72 static void tcf_mirred_release(struct tc_action *a)
74 struct tcf_mirred *m = to_mirred(a);
75 struct net_device *dev;
77 spin_lock(&mirred_list_lock);
78 list_del(&m->tcfm_list);
79 spin_unlock(&mirred_list_lock);
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);
86 static 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),
91 static struct tc_action_ops act_mirred_ops;
93 static void tcf_mirred_replace_dev(struct tcf_mirred *m,
94 struct net_device *ndev)
96 struct net_device *odev;
98 odev = rcu_replace_pointer(m->tcfm_dev, ndev,
99 lockdep_is_held(&m->tcf_lock));
100 netdev_put(odev, &m->tcfm_dev_tracker);
103 static 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)
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;
120 NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
123 ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla,
124 mirred_policy, extack);
127 if (!tb[TCA_MIRRED_PARMS]) {
128 NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
131 parm = nla_data(tb[TCA_MIRRED_PARMS]);
133 err = tcf_idr_check_alloc(tn, &index, a, bind);
140 if (tb[TCA_MIRRED_BLOCKID] && parm->ifindex) {
141 NL_SET_ERR_MSG_MOD(extack,
142 "Cannot specify Block ID and dev simultaneously");
144 tcf_idr_release(*a, bind);
146 tcf_idr_cleanup(tn, index);
151 switch (parm->eaction) {
152 case TCA_EGRESS_MIRROR:
153 case TCA_EGRESS_REDIR:
154 case TCA_INGRESS_REDIR:
155 case TCA_INGRESS_MIRROR:
159 tcf_idr_release(*a, bind);
161 tcf_idr_cleanup(tn, index);
162 NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
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");
173 ret = tcf_idr_create_from_flags(tn, index, est, a,
174 &act_mirred_ops, bind, flags);
176 tcf_idr_cleanup(tn, index);
180 } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
181 tcf_idr_release(*a, bind);
186 if (ret == ACT_P_CREATED)
187 INIT_LIST_HEAD(&m->tcfm_list);
189 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
193 spin_lock_bh(&m->tcf_lock);
196 struct net_device *ndev;
198 ndev = dev_get_by_index(net, parm->ifindex);
200 spin_unlock_bh(&m->tcf_lock);
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;
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]);
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);
218 tcf_chain_put_by_act(goto_ch);
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);
229 tcf_chain_put_by_act(goto_ch);
231 tcf_idr_release(*a, bind);
236 tcf_mirred_forward(bool at_ingress, bool want_ingress, struct sk_buff *skb)
241 err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
242 else if (!at_ingress)
245 err = netif_receive_skb(skb);
250 static 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,
255 struct sk_buff *skb_to_send = skb;
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",
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.
276 at_ingress = skb_at_tc_ingress(skb);
277 dont_clone = skb_at_tc_ingress(skb) && is_redirect &&
278 tcf_mirred_can_reinsert(retval);
280 skb_to_send = skb_clone(skb, GFP_ATOMIC);
285 want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
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);
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);
298 /* target device/action expect data at nh */
299 skb_pull_rcsum(skb_to_send, mac_len);
301 /* target device/action expect data at mac */
302 skb_push_rcsum(skb_to_send, mac_len);
306 skb_to_send->skb_iif = skb->dev->ifindex;
307 skb_to_send->dev = dev;
310 if (skb == skb_to_send)
311 retval = TC_ACT_CONSUMED;
313 skb_set_redirected(skb_to_send, skb_to_send->tc_at_ingress);
315 err = tcf_mirred_forward(at_ingress, want_ingress, skb_to_send);
317 err = tcf_mirred_forward(at_ingress, want_ingress, skb_to_send);
320 tcf_action_inc_overlimit_qstats(&m->common);
326 retval = TC_ACT_SHOT;
327 tcf_action_inc_overlimit_qstats(&m->common);
331 static 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)
335 struct net_device *dev_prev = NULL;
336 struct net_device *dev = NULL;
340 mirred_eaction = tcf_mirred_act_wants_ingress(m_eaction) ?
341 TCA_INGRESS_MIRROR : TCA_EGRESS_MIRROR;
343 xa_for_each(&block->ports, index, dev) {
344 if (index == exception_ifindex)
350 tcf_mirred_to_dev(skb, m, dev_prev,
351 dev_is_mac_header_xmit(dev),
352 mirred_eaction, retval);
358 return tcf_mirred_to_dev(skb, m, dev_prev,
359 dev_is_mac_header_xmit(dev_prev),
365 static 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)
369 struct net_device *dev = NULL;
372 xa_for_each(&block->ports, index, dev) {
373 if (index == exception_ifindex)
376 tcf_mirred_to_dev(skb, m, dev,
377 dev_is_mac_header_xmit(dev),
384 static int tcf_blockcast(struct sk_buff *skb, struct tcf_mirred *m,
385 const u32 blockid, struct tcf_result *res,
388 const u32 exception_ifindex = skb->dev->ifindex;
389 struct tcf_block *block;
393 m_eaction = READ_ONCE(m->tcfm_eaction);
394 is_redirect = tcf_mirred_is_act_redirect(m_eaction);
396 /* we are already under rcu protection, so can call block lookup
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);
406 return tcf_blockcast_redir(skb, m, block, m_eaction,
407 exception_ifindex, retval);
409 /* If it's not redirect, it is mirror */
410 return tcf_blockcast_mirror(skb, m, block, m_eaction, exception_ifindex,
414 TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb,
415 const struct tc_action *a,
416 struct tcf_result *res)
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;
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;
434 tcf_lastuse_update(&m->tcf_tm);
435 tcf_action_update_bstats(&m->common, skb);
437 blockid = READ_ONCE(m->tcfm_blockid);
439 retval = tcf_blockcast(skb, m, blockid, res, retval);
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);
450 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
451 m_eaction = READ_ONCE(m->tcfm_eaction);
453 retval = tcf_mirred_to_dev(skb, m, dev, m_mac_header_xmit, m_eaction,
457 __this_cpu_dec(mirred_nest_level);
462 static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets,
463 u64 drops, u64 lastuse, bool hw)
465 struct tcf_mirred *m = to_mirred(a);
466 struct tcf_t *tm = &m->tcf_tm;
468 tcf_action_update_stats(a, bytes, packets, drops, hw);
469 tm->lastuse = max_t(u64, tm->lastuse, lastuse);
472 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
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,
482 struct net_device *dev;
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);
491 opt.ifindex = dev->ifindex;
493 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
494 goto nla_put_failure;
496 blockid = m->tcfm_blockid;
497 if (blockid && nla_put_u32(skb, TCA_MIRRED_BLOCKID, blockid))
498 goto nla_put_failure;
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);
508 spin_unlock_bh(&m->tcf_lock);
513 static int mirred_device_event(struct notifier_block *unused,
514 unsigned long event, void *ptr)
516 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
517 struct tcf_mirred *m;
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.
529 RCU_INIT_POINTER(m->tcfm_dev, NULL);
531 spin_unlock_bh(&m->tcf_lock);
533 spin_unlock(&mirred_list_lock);
539 static struct notifier_block mirred_device_notifier = {
540 .notifier_call = mirred_device_event,
543 static void tcf_mirred_dev_put(void *priv)
545 struct net_device *dev = priv;
550 static struct net_device *
551 tcf_mirred_get_dev(const struct tc_action *a,
552 tc_action_priv_destructor *destructor)
554 struct tcf_mirred *m = to_mirred(a);
555 struct net_device *dev;
558 dev = rcu_dereference(m->tcfm_dev);
561 *destructor = tcf_mirred_dev_put;
568 static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
570 return nla_total_size(sizeof(struct tc_mirred));
573 static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry,
574 const struct tc_action *act)
576 entry->dev = act->ops->get_dev(act, &entry->destructor);
579 entry->destructor_priv = entry->dev;
582 static 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)
587 struct flow_action_entry *entry = entry_data;
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);
602 NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload");
607 struct flow_offload_action *fl_action = entry_data;
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;
624 static struct tc_action_ops act_mirred_ops = {
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,
639 static __net_init int mirred_init_net(struct net *net)
641 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
643 return tc_action_net_init(net, tn, &act_mirred_ops);
646 static void __net_exit mirred_exit_net(struct list_head *net_list)
648 tc_action_net_exit(net_list, act_mirred_ops.net_id);
651 static struct pernet_operations mirred_net_ops = {
652 .init = mirred_init_net,
653 .exit_batch = mirred_exit_net,
654 .id = &act_mirred_ops.net_id,
655 .size = sizeof(struct tc_action_net),
658 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
659 MODULE_DESCRIPTION("Device Mirror/redirect actions");
660 MODULE_LICENSE("GPL");
662 static int __init mirred_init_module(void)
664 int err = register_netdevice_notifier(&mirred_device_notifier);
668 pr_info("Mirror/redirect action on\n");
669 err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
671 unregister_netdevice_notifier(&mirred_device_notifier);
676 static void __exit mirred_cleanup_module(void)
678 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
679 unregister_netdevice_notifier(&mirred_device_notifier);
682 module_init(mirred_init_module);
683 module_exit(mirred_cleanup_module);