2 * net/sched/act_mirred.c packet mirroring and redirect actions
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * Authors: Jamal Hadi Salim (2002-4)
11 * TODO: Add ingress support (and socket redirect support)
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/skbuff.h>
20 #include <linux/rtnetlink.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/gfp.h>
24 #include <linux/if_arp.h>
25 #include <net/net_namespace.h>
26 #include <net/netlink.h>
27 #include <net/pkt_sched.h>
28 #include <linux/tc_act/tc_mirred.h>
29 #include <net/tc_act/tc_mirred.h>
31 static LIST_HEAD(mirred_list);
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 void tcf_mirred_release(struct tc_action *a)
54 struct tcf_mirred *m = to_mirred(a);
55 struct net_device *dev;
57 list_del(&m->tcfm_list);
58 dev = rtnl_dereference(m->tcfm_dev);
63 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
64 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
67 static unsigned int mirred_net_id;
68 static struct tc_action_ops act_mirred_ops;
70 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
71 struct nlattr *est, struct tc_action **a, int ovr,
72 int bind, struct netlink_ext_ack *extack)
74 struct tc_action_net *tn = net_generic(net, mirred_net_id);
75 struct nlattr *tb[TCA_MIRRED_MAX + 1];
76 bool mac_header_xmit = false;
77 struct tc_mirred *parm;
79 struct net_device *dev;
84 NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
87 ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy, extack);
90 if (!tb[TCA_MIRRED_PARMS]) {
91 NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
94 parm = nla_data(tb[TCA_MIRRED_PARMS]);
96 exists = tcf_idr_check(tn, parm->index, a, bind);
100 switch (parm->eaction) {
101 case TCA_EGRESS_MIRROR:
102 case TCA_EGRESS_REDIR:
103 case TCA_INGRESS_REDIR:
104 case TCA_INGRESS_MIRROR:
108 tcf_idr_release(*a, bind);
109 NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
113 dev = __dev_get_by_index(net, parm->ifindex);
116 tcf_idr_release(*a, bind);
119 mac_header_xmit = dev_is_mac_header_xmit(dev);
126 NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
129 ret = tcf_idr_create(tn, parm->index, est, a,
130 &act_mirred_ops, bind, true);
135 tcf_idr_release(*a, bind);
142 m->tcf_action = parm->action;
143 m->tcfm_eaction = parm->eaction;
145 if (ret != ACT_P_CREATED)
146 dev_put(rcu_dereference_protected(m->tcfm_dev, 1));
148 rcu_assign_pointer(m->tcfm_dev, dev);
149 m->tcfm_mac_header_xmit = mac_header_xmit;
152 if (ret == ACT_P_CREATED) {
153 list_add(&m->tcfm_list, &mirred_list);
154 tcf_idr_insert(tn, *a);
160 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
161 struct tcf_result *res)
163 struct tcf_mirred *m = to_mirred(a);
164 bool m_mac_header_xmit;
165 struct net_device *dev;
166 struct sk_buff *skb2;
171 tcf_lastuse_update(&m->tcf_tm);
172 bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
175 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
176 m_eaction = READ_ONCE(m->tcfm_eaction);
177 retval = READ_ONCE(m->tcf_action);
178 dev = rcu_dereference(m->tcfm_dev);
179 if (unlikely(!dev)) {
180 pr_notice_once("tc mirred: target device is gone\n");
184 if (unlikely(!(dev->flags & IFF_UP))) {
185 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
190 skb2 = skb_clone(skb, GFP_ATOMIC);
194 /* If action's target direction differs than filter's direction,
195 * and devices expect a mac header on xmit, then mac push/pull is
198 if (skb_at_tc_ingress(skb) != tcf_mirred_act_wants_ingress(m_eaction) &&
200 if (!skb_at_tc_ingress(skb)) {
201 /* caught at egress, act ingress: pull mac */
202 mac_len = skb_network_header(skb) - skb_mac_header(skb);
203 skb_pull_rcsum(skb2, mac_len);
205 /* caught at ingress, act egress: push mac */
206 skb_push_rcsum(skb2, skb->mac_len);
210 /* mirror is always swallowed */
211 if (tcf_mirred_is_act_redirect(m_eaction)) {
212 skb2->tc_redirected = 1;
213 skb2->tc_from_ingress = skb2->tc_at_ingress;
216 skb2->skb_iif = skb->dev->ifindex;
218 if (!tcf_mirred_act_wants_ingress(m_eaction))
219 err = dev_queue_xmit(skb2);
221 err = netif_receive_skb(skb2);
225 qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
226 if (tcf_mirred_is_act_redirect(m_eaction))
227 retval = TC_ACT_SHOT;
234 static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets,
237 struct tcf_mirred *m = to_mirred(a);
238 struct tcf_t *tm = &m->tcf_tm;
240 _bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets);
241 tm->lastuse = max_t(u64, tm->lastuse, lastuse);
244 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
247 unsigned char *b = skb_tail_pointer(skb);
248 struct tcf_mirred *m = to_mirred(a);
249 struct net_device *dev = rtnl_dereference(m->tcfm_dev);
250 struct tc_mirred opt = {
251 .index = m->tcf_index,
252 .action = m->tcf_action,
253 .refcnt = m->tcf_refcnt - ref,
254 .bindcnt = m->tcf_bindcnt - bind,
255 .eaction = m->tcfm_eaction,
256 .ifindex = dev ? dev->ifindex : 0,
260 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
261 goto nla_put_failure;
263 tcf_tm_dump(&t, &m->tcf_tm);
264 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
265 goto nla_put_failure;
273 static int tcf_mirred_walker(struct net *net, struct sk_buff *skb,
274 struct netlink_callback *cb, int type,
275 const struct tc_action_ops *ops,
276 struct netlink_ext_ack *extack)
278 struct tc_action_net *tn = net_generic(net, mirred_net_id);
280 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
283 static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index,
284 struct netlink_ext_ack *extack)
286 struct tc_action_net *tn = net_generic(net, mirred_net_id);
288 return tcf_idr_search(tn, a, index);
291 static int mirred_device_event(struct notifier_block *unused,
292 unsigned long event, void *ptr)
294 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
295 struct tcf_mirred *m;
298 if (event == NETDEV_UNREGISTER) {
299 list_for_each_entry(m, &mirred_list, tcfm_list) {
300 if (rcu_access_pointer(m->tcfm_dev) == dev) {
302 /* Note : no rcu grace period necessary, as
303 * net_device are already rcu protected.
305 RCU_INIT_POINTER(m->tcfm_dev, NULL);
313 static struct notifier_block mirred_device_notifier = {
314 .notifier_call = mirred_device_event,
317 static struct net_device *tcf_mirred_get_dev(const struct tc_action *a)
319 struct tcf_mirred *m = to_mirred(a);
321 return rtnl_dereference(m->tcfm_dev);
324 static struct tc_action_ops act_mirred_ops = {
326 .type = TCA_ACT_MIRRED,
327 .owner = THIS_MODULE,
329 .stats_update = tcf_stats_update,
330 .dump = tcf_mirred_dump,
331 .cleanup = tcf_mirred_release,
332 .init = tcf_mirred_init,
333 .walk = tcf_mirred_walker,
334 .lookup = tcf_mirred_search,
335 .size = sizeof(struct tcf_mirred),
336 .get_dev = tcf_mirred_get_dev,
339 static __net_init int mirred_init_net(struct net *net)
341 struct tc_action_net *tn = net_generic(net, mirred_net_id);
343 return tc_action_net_init(tn, &act_mirred_ops);
346 static void __net_exit mirred_exit_net(struct list_head *net_list)
348 tc_action_net_exit(net_list, mirred_net_id);
351 static struct pernet_operations mirred_net_ops = {
352 .init = mirred_init_net,
353 .exit_batch = mirred_exit_net,
354 .id = &mirred_net_id,
355 .size = sizeof(struct tc_action_net),
358 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
359 MODULE_DESCRIPTION("Device Mirror/redirect actions");
360 MODULE_LICENSE("GPL");
362 static int __init mirred_init_module(void)
364 int err = register_netdevice_notifier(&mirred_device_notifier);
368 pr_info("Mirror/redirect action on\n");
369 return tcf_register_action(&act_mirred_ops, &mirred_net_ops);
372 static void __exit mirred_cleanup_module(void)
374 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
375 unregister_netdevice_notifier(&mirred_device_notifier);
378 module_init(mirred_init_module);
379 module_exit(mirred_cleanup_module);