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>
22 #include <net/pkt_sched.h>
23 #include <net/pkt_cls.h>
24 #include <linux/tc_act/tc_mirred.h>
25 #include <net/tc_act/tc_mirred.h>
27 static LIST_HEAD(mirred_list);
28 static DEFINE_SPINLOCK(mirred_list_lock);
30 #define MIRRED_RECURSION_LIMIT 4
31 static DEFINE_PER_CPU(unsigned int, mirred_rec_level);
33 static bool tcf_mirred_is_act_redirect(int action)
35 return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR;
38 static bool tcf_mirred_act_wants_ingress(int action)
41 case TCA_EGRESS_REDIR:
42 case TCA_EGRESS_MIRROR:
44 case TCA_INGRESS_REDIR:
45 case TCA_INGRESS_MIRROR:
52 static bool tcf_mirred_can_reinsert(int action)
64 static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m)
66 return rcu_dereference_protected(m->tcfm_dev,
67 lockdep_is_held(&m->tcf_lock));
70 static void tcf_mirred_release(struct tc_action *a)
72 struct tcf_mirred *m = to_mirred(a);
73 struct net_device *dev;
75 spin_lock(&mirred_list_lock);
76 list_del(&m->tcfm_list);
77 spin_unlock(&mirred_list_lock);
79 /* last reference to action, no need to lock */
80 dev = rcu_dereference_protected(m->tcfm_dev, 1);
85 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
86 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
89 static unsigned int mirred_net_id;
90 static struct tc_action_ops act_mirred_ops;
92 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
93 struct nlattr *est, struct tc_action **a,
94 int ovr, int bind, bool rtnl_held,
96 struct netlink_ext_ack *extack)
98 struct tc_action_net *tn = net_generic(net, mirred_net_id);
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 struct net_device *dev;
109 NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
112 ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla,
113 mirred_policy, extack);
116 if (!tb[TCA_MIRRED_PARMS]) {
117 NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
120 parm = nla_data(tb[TCA_MIRRED_PARMS]);
122 err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
129 switch (parm->eaction) {
130 case TCA_EGRESS_MIRROR:
131 case TCA_EGRESS_REDIR:
132 case TCA_INGRESS_REDIR:
133 case TCA_INGRESS_MIRROR:
137 tcf_idr_release(*a, bind);
139 tcf_idr_cleanup(tn, parm->index);
140 NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
145 if (!parm->ifindex) {
146 tcf_idr_cleanup(tn, parm->index);
147 NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
150 ret = tcf_idr_create(tn, parm->index, est, a,
151 &act_mirred_ops, bind, true);
153 tcf_idr_cleanup(tn, parm->index);
158 tcf_idr_release(*a, bind);
163 if (ret == ACT_P_CREATED)
164 INIT_LIST_HEAD(&m->tcfm_list);
166 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
170 spin_lock_bh(&m->tcf_lock);
173 dev = dev_get_by_index(net, parm->ifindex);
175 spin_unlock_bh(&m->tcf_lock);
179 mac_header_xmit = dev_is_mac_header_xmit(dev);
180 rcu_swap_protected(m->tcfm_dev, dev,
181 lockdep_is_held(&m->tcf_lock));
184 m->tcfm_mac_header_xmit = mac_header_xmit;
186 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
187 m->tcfm_eaction = parm->eaction;
188 spin_unlock_bh(&m->tcf_lock);
190 tcf_chain_put_by_act(goto_ch);
192 if (ret == ACT_P_CREATED) {
193 spin_lock(&mirred_list_lock);
194 list_add(&m->tcfm_list, &mirred_list);
195 spin_unlock(&mirred_list_lock);
197 tcf_idr_insert(tn, *a);
203 tcf_chain_put_by_act(goto_ch);
205 tcf_idr_release(*a, bind);
209 static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
210 struct tcf_result *res)
212 struct tcf_mirred *m = to_mirred(a);
213 struct sk_buff *skb2 = skb;
214 bool m_mac_header_xmit;
215 struct net_device *dev;
216 unsigned int rec_level;
224 rec_level = __this_cpu_inc_return(mirred_rec_level);
225 if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) {
226 net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
227 netdev_name(skb->dev));
228 __this_cpu_dec(mirred_rec_level);
232 tcf_lastuse_update(&m->tcf_tm);
233 bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
235 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
236 m_eaction = READ_ONCE(m->tcfm_eaction);
237 retval = READ_ONCE(m->tcf_action);
238 dev = rcu_dereference_bh(m->tcfm_dev);
239 if (unlikely(!dev)) {
240 pr_notice_once("tc mirred: target device is gone\n");
244 if (unlikely(!(dev->flags & IFF_UP))) {
245 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
250 /* we could easily avoid the clone only if called by ingress and clsact;
251 * since we can't easily detect the clsact caller, skip clone only for
252 * ingress - that covers the TC S/W datapath.
254 is_redirect = tcf_mirred_is_act_redirect(m_eaction);
255 use_reinsert = skb_at_tc_ingress(skb) && is_redirect &&
256 tcf_mirred_can_reinsert(retval);
258 skb2 = skb_clone(skb, GFP_ATOMIC);
263 /* If action's target direction differs than filter's direction,
264 * and devices expect a mac header on xmit, then mac push/pull is
267 want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
268 if (skb_at_tc_ingress(skb) != want_ingress && m_mac_header_xmit) {
269 if (!skb_at_tc_ingress(skb)) {
270 /* caught at egress, act ingress: pull mac */
271 mac_len = skb_network_header(skb) - skb_mac_header(skb);
272 skb_pull_rcsum(skb2, mac_len);
274 /* caught at ingress, act egress: push mac */
275 skb_push_rcsum(skb2, skb->mac_len);
279 skb2->skb_iif = skb->dev->ifindex;
282 /* mirror is always swallowed */
284 skb2->tc_redirected = 1;
285 skb2->tc_from_ingress = skb2->tc_at_ingress;
286 if (skb2->tc_from_ingress)
288 /* let's the caller reinsert the packet, if possible */
290 res->ingress = want_ingress;
291 res->qstats = this_cpu_ptr(m->common.cpu_qstats);
292 skb_tc_reinsert(skb, res);
293 __this_cpu_dec(mirred_rec_level);
294 return TC_ACT_CONSUMED;
299 err = dev_queue_xmit(skb2);
301 err = netif_receive_skb(skb2);
305 qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
306 if (tcf_mirred_is_act_redirect(m_eaction))
307 retval = TC_ACT_SHOT;
309 __this_cpu_dec(mirred_rec_level);
314 static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets,
315 u64 lastuse, bool hw)
317 struct tcf_mirred *m = to_mirred(a);
318 struct tcf_t *tm = &m->tcf_tm;
320 _bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets);
322 _bstats_cpu_update(this_cpu_ptr(a->cpu_bstats_hw),
324 tm->lastuse = max_t(u64, tm->lastuse, lastuse);
327 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
330 unsigned char *b = skb_tail_pointer(skb);
331 struct tcf_mirred *m = to_mirred(a);
332 struct tc_mirred opt = {
333 .index = m->tcf_index,
334 .refcnt = refcount_read(&m->tcf_refcnt) - ref,
335 .bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
337 struct net_device *dev;
340 spin_lock_bh(&m->tcf_lock);
341 opt.action = m->tcf_action;
342 opt.eaction = m->tcfm_eaction;
343 dev = tcf_mirred_dev_dereference(m);
345 opt.ifindex = dev->ifindex;
347 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
348 goto nla_put_failure;
350 tcf_tm_dump(&t, &m->tcf_tm);
351 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
352 goto nla_put_failure;
353 spin_unlock_bh(&m->tcf_lock);
358 spin_unlock_bh(&m->tcf_lock);
363 static int tcf_mirred_walker(struct net *net, struct sk_buff *skb,
364 struct netlink_callback *cb, int type,
365 const struct tc_action_ops *ops,
366 struct netlink_ext_ack *extack)
368 struct tc_action_net *tn = net_generic(net, mirred_net_id);
370 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
373 static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index)
375 struct tc_action_net *tn = net_generic(net, mirred_net_id);
377 return tcf_idr_search(tn, a, index);
380 static int mirred_device_event(struct notifier_block *unused,
381 unsigned long event, void *ptr)
383 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
384 struct tcf_mirred *m;
387 if (event == NETDEV_UNREGISTER) {
388 spin_lock(&mirred_list_lock);
389 list_for_each_entry(m, &mirred_list, tcfm_list) {
390 spin_lock_bh(&m->tcf_lock);
391 if (tcf_mirred_dev_dereference(m) == dev) {
393 /* Note : no rcu grace period necessary, as
394 * net_device are already rcu protected.
396 RCU_INIT_POINTER(m->tcfm_dev, NULL);
398 spin_unlock_bh(&m->tcf_lock);
400 spin_unlock(&mirred_list_lock);
406 static struct notifier_block mirred_device_notifier = {
407 .notifier_call = mirred_device_event,
410 static struct net_device *tcf_mirred_get_dev(const struct tc_action *a)
412 struct tcf_mirred *m = to_mirred(a);
413 struct net_device *dev;
416 dev = rcu_dereference(m->tcfm_dev);
424 static void tcf_mirred_put_dev(struct net_device *dev)
429 static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
431 return nla_total_size(sizeof(struct tc_mirred));
434 static struct tc_action_ops act_mirred_ops = {
437 .owner = THIS_MODULE,
438 .act = tcf_mirred_act,
439 .stats_update = tcf_stats_update,
440 .dump = tcf_mirred_dump,
441 .cleanup = tcf_mirred_release,
442 .init = tcf_mirred_init,
443 .walk = tcf_mirred_walker,
444 .lookup = tcf_mirred_search,
445 .get_fill_size = tcf_mirred_get_fill_size,
446 .size = sizeof(struct tcf_mirred),
447 .get_dev = tcf_mirred_get_dev,
448 .put_dev = tcf_mirred_put_dev,
451 static __net_init int mirred_init_net(struct net *net)
453 struct tc_action_net *tn = net_generic(net, mirred_net_id);
455 return tc_action_net_init(tn, &act_mirred_ops);
458 static void __net_exit mirred_exit_net(struct list_head *net_list)
460 tc_action_net_exit(net_list, mirred_net_id);
463 static struct pernet_operations mirred_net_ops = {
464 .init = mirred_init_net,
465 .exit_batch = mirred_exit_net,
466 .id = &mirred_net_id,
467 .size = sizeof(struct tc_action_net),
470 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
471 MODULE_DESCRIPTION("Device Mirror/redirect actions");
472 MODULE_LICENSE("GPL");
474 static int __init mirred_init_module(void)
476 int err = register_netdevice_notifier(&mirred_device_notifier);
480 pr_info("Mirror/redirect action on\n");
481 return tcf_register_action(&act_mirred_ops, &mirred_net_ops);
484 static void __exit mirred_cleanup_module(void)
486 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
487 unregister_netdevice_notifier(&mirred_device_notifier);
490 module_init(mirred_init_module);
491 module_exit(mirred_cleanup_module);