1 // SPDX-License-Identifier: GPL-2.0-only
3 * net/sched/act_sample.c - Packet sampling tc action
4 * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
7 #include <linux/types.h>
8 #include <linux/kernel.h>
9 #include <linux/string.h>
10 #include <linux/errno.h>
11 #include <linux/skbuff.h>
12 #include <linux/rtnetlink.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/gfp.h>
16 #include <net/net_namespace.h>
17 #include <net/netlink.h>
18 #include <net/pkt_sched.h>
19 #include <linux/tc_act/tc_sample.h>
20 #include <net/tc_act/tc_sample.h>
21 #include <net/psample.h>
22 #include <net/pkt_cls.h>
24 #include <linux/if_arp.h>
26 static unsigned int sample_net_id;
27 static struct tc_action_ops act_sample_ops;
29 static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = {
30 [TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) },
31 [TCA_SAMPLE_RATE] = { .type = NLA_U32 },
32 [TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 },
33 [TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 },
36 static int tcf_sample_init(struct net *net, struct nlattr *nla,
37 struct nlattr *est, struct tc_action **a,
39 u32 flags, struct netlink_ext_ack *extack)
41 struct tc_action_net *tn = net_generic(net, sample_net_id);
42 bool bind = flags & TCA_ACT_FLAGS_BIND;
43 struct nlattr *tb[TCA_SAMPLE_MAX + 1];
44 struct psample_group *psample_group;
45 u32 psample_group_num, rate, index;
46 struct tcf_chain *goto_ch = NULL;
47 struct tc_sample *parm;
54 ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla,
58 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] ||
59 !tb[TCA_SAMPLE_PSAMPLE_GROUP])
62 parm = nla_data(tb[TCA_SAMPLE_PARMS]);
64 err = tcf_idr_check_alloc(tn, &index, a, bind);
72 ret = tcf_idr_create(tn, index, est, a,
73 &act_sample_ops, bind, true, flags);
75 tcf_idr_cleanup(tn, index);
79 } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
80 tcf_idr_release(*a, bind);
83 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
87 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
89 NL_SET_ERR_MSG(extack, "invalid sample rate");
93 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
94 psample_group = psample_group_get(net, psample_group_num);
102 spin_lock_bh(&s->tcf_lock);
103 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
105 s->psample_group_num = psample_group_num;
106 psample_group = rcu_replace_pointer(s->psample_group, psample_group,
107 lockdep_is_held(&s->tcf_lock));
109 if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
111 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
113 spin_unlock_bh(&s->tcf_lock);
116 psample_group_put(psample_group);
118 tcf_chain_put_by_act(goto_ch);
123 tcf_chain_put_by_act(goto_ch);
125 tcf_idr_release(*a, bind);
129 static void tcf_sample_cleanup(struct tc_action *a)
131 struct tcf_sample *s = to_sample(a);
132 struct psample_group *psample_group;
134 /* last reference to action, no need to lock */
135 psample_group = rcu_dereference_protected(s->psample_group, 1);
136 RCU_INIT_POINTER(s->psample_group, NULL);
138 psample_group_put(psample_group);
141 static bool tcf_sample_dev_ok_push(struct net_device *dev)
157 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
158 struct tcf_result *res)
160 struct tcf_sample *s = to_sample(a);
161 struct psample_group *psample_group;
162 struct psample_metadata md = {};
165 tcf_lastuse_update(&s->tcf_tm);
166 bstats_update(this_cpu_ptr(s->common.cpu_bstats), skb);
167 retval = READ_ONCE(s->tcf_action);
169 psample_group = rcu_dereference_bh(s->psample_group);
171 /* randomly sample packets according to rate */
172 if (psample_group && (prandom_u32() % s->rate == 0)) {
173 if (!skb_at_tc_ingress(skb)) {
174 md.in_ifindex = skb->skb_iif;
175 md.out_ifindex = skb->dev->ifindex;
177 md.in_ifindex = skb->dev->ifindex;
180 /* on ingress, the mac header gets popped, so push it back */
181 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
182 skb_push(skb, skb->mac_len);
184 md.trunc_size = s->truncate ? s->trunc_size : skb->len;
185 psample_sample_packet(psample_group, skb, s->rate, &md);
187 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
188 skb_pull(skb, skb->mac_len);
194 static void tcf_sample_stats_update(struct tc_action *a, u64 bytes, u64 packets,
195 u64 drops, u64 lastuse, bool hw)
197 struct tcf_sample *s = to_sample(a);
198 struct tcf_t *tm = &s->tcf_tm;
200 tcf_action_update_stats(a, bytes, packets, drops, hw);
201 tm->lastuse = max_t(u64, tm->lastuse, lastuse);
204 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
207 unsigned char *b = skb_tail_pointer(skb);
208 struct tcf_sample *s = to_sample(a);
209 struct tc_sample opt = {
210 .index = s->tcf_index,
211 .refcnt = refcount_read(&s->tcf_refcnt) - ref,
212 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind,
216 spin_lock_bh(&s->tcf_lock);
217 opt.action = s->tcf_action;
218 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
219 goto nla_put_failure;
221 tcf_tm_dump(&t, &s->tcf_tm);
222 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
223 goto nla_put_failure;
225 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
226 goto nla_put_failure;
229 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
230 goto nla_put_failure;
232 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
233 goto nla_put_failure;
234 spin_unlock_bh(&s->tcf_lock);
239 spin_unlock_bh(&s->tcf_lock);
244 static int tcf_sample_walker(struct net *net, struct sk_buff *skb,
245 struct netlink_callback *cb, int type,
246 const struct tc_action_ops *ops,
247 struct netlink_ext_ack *extack)
249 struct tc_action_net *tn = net_generic(net, sample_net_id);
251 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
254 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
256 struct tc_action_net *tn = net_generic(net, sample_net_id);
258 return tcf_idr_search(tn, a, index);
261 static void tcf_psample_group_put(void *priv)
263 struct psample_group *group = priv;
265 psample_group_put(group);
268 static struct psample_group *
269 tcf_sample_get_group(const struct tc_action *a,
270 tc_action_priv_destructor *destructor)
272 struct tcf_sample *s = to_sample(a);
273 struct psample_group *group;
275 group = rcu_dereference_protected(s->psample_group,
276 lockdep_is_held(&s->tcf_lock));
278 psample_group_take(group);
279 *destructor = tcf_psample_group_put;
285 static void tcf_offload_sample_get_group(struct flow_action_entry *entry,
286 const struct tc_action *act)
288 entry->sample.psample_group =
289 act->ops->get_psample_group(act, &entry->destructor);
290 entry->destructor_priv = entry->sample.psample_group;
293 static int tcf_sample_offload_act_setup(struct tc_action *act, void *entry_data,
294 u32 *index_inc, bool bind)
297 struct flow_action_entry *entry = entry_data;
299 entry->id = FLOW_ACTION_SAMPLE;
300 entry->sample.trunc_size = tcf_sample_trunc_size(act);
301 entry->sample.truncate = tcf_sample_truncate(act);
302 entry->sample.rate = tcf_sample_rate(act);
303 tcf_offload_sample_get_group(entry, act);
306 struct flow_offload_action *fl_action = entry_data;
308 fl_action->id = FLOW_ACTION_SAMPLE;
314 static struct tc_action_ops act_sample_ops = {
317 .owner = THIS_MODULE,
318 .act = tcf_sample_act,
319 .stats_update = tcf_sample_stats_update,
320 .dump = tcf_sample_dump,
321 .init = tcf_sample_init,
322 .cleanup = tcf_sample_cleanup,
323 .walk = tcf_sample_walker,
324 .lookup = tcf_sample_search,
325 .get_psample_group = tcf_sample_get_group,
326 .offload_act_setup = tcf_sample_offload_act_setup,
327 .size = sizeof(struct tcf_sample),
330 static __net_init int sample_init_net(struct net *net)
332 struct tc_action_net *tn = net_generic(net, sample_net_id);
334 return tc_action_net_init(net, tn, &act_sample_ops);
337 static void __net_exit sample_exit_net(struct list_head *net_list)
339 tc_action_net_exit(net_list, sample_net_id);
342 static struct pernet_operations sample_net_ops = {
343 .init = sample_init_net,
344 .exit_batch = sample_exit_net,
345 .id = &sample_net_id,
346 .size = sizeof(struct tc_action_net),
349 static int __init sample_init_module(void)
351 return tcf_register_action(&act_sample_ops, &sample_net_ops);
354 static void __exit sample_cleanup_module(void)
356 tcf_unregister_action(&act_sample_ops, &sample_net_ops);
359 module_init(sample_init_module);
360 module_exit(sample_cleanup_module);
362 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
363 MODULE_DESCRIPTION("Packet sampling action");
364 MODULE_LICENSE("GPL v2");