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, int ovr,
38 int bind, bool rtnl_held, struct tcf_proto *tp,
39 u32 flags, struct netlink_ext_ack *extack)
41 struct tc_action_net *tn = net_generic(net, sample_net_id);
42 struct nlattr *tb[TCA_SAMPLE_MAX + 1];
43 struct psample_group *psample_group;
44 u32 psample_group_num, rate, index;
45 struct tcf_chain *goto_ch = NULL;
46 struct tc_sample *parm;
53 ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla,
57 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] ||
58 !tb[TCA_SAMPLE_PSAMPLE_GROUP])
61 parm = nla_data(tb[TCA_SAMPLE_PARMS]);
63 err = tcf_idr_check_alloc(tn, &index, a, bind);
71 ret = tcf_idr_create(tn, index, est, a,
72 &act_sample_ops, bind, true, 0);
74 tcf_idr_cleanup(tn, index);
79 tcf_idr_release(*a, bind);
82 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
86 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
88 NL_SET_ERR_MSG(extack, "invalid sample rate");
92 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
93 psample_group = psample_group_get(net, psample_group_num);
101 spin_lock_bh(&s->tcf_lock);
102 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
104 s->psample_group_num = psample_group_num;
105 psample_group = rcu_replace_pointer(s->psample_group, psample_group,
106 lockdep_is_held(&s->tcf_lock));
108 if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
110 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
112 spin_unlock_bh(&s->tcf_lock);
115 psample_group_put(psample_group);
117 tcf_chain_put_by_act(goto_ch);
119 if (ret == ACT_P_CREATED)
120 tcf_idr_insert(tn, *a);
124 tcf_chain_put_by_act(goto_ch);
126 tcf_idr_release(*a, bind);
130 static void tcf_sample_cleanup(struct tc_action *a)
132 struct tcf_sample *s = to_sample(a);
133 struct psample_group *psample_group;
135 /* last reference to action, no need to lock */
136 psample_group = rcu_dereference_protected(s->psample_group, 1);
137 RCU_INIT_POINTER(s->psample_group, NULL);
139 psample_group_put(psample_group);
142 static bool tcf_sample_dev_ok_push(struct net_device *dev)
158 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
159 struct tcf_result *res)
161 struct tcf_sample *s = to_sample(a);
162 struct psample_group *psample_group;
168 tcf_lastuse_update(&s->tcf_tm);
169 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
170 retval = READ_ONCE(s->tcf_action);
172 psample_group = rcu_dereference_bh(s->psample_group);
174 /* randomly sample packets according to rate */
175 if (psample_group && (prandom_u32() % s->rate == 0)) {
176 if (!skb_at_tc_ingress(skb)) {
178 oif = skb->dev->ifindex;
180 iif = skb->dev->ifindex;
184 /* on ingress, the mac header gets popped, so push it back */
185 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
186 skb_push(skb, skb->mac_len);
188 size = s->truncate ? s->trunc_size : skb->len;
189 psample_sample_packet(psample_group, skb, size, iif, oif,
192 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
193 skb_pull(skb, skb->mac_len);
199 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
202 unsigned char *b = skb_tail_pointer(skb);
203 struct tcf_sample *s = to_sample(a);
204 struct tc_sample opt = {
205 .index = s->tcf_index,
206 .refcnt = refcount_read(&s->tcf_refcnt) - ref,
207 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind,
211 spin_lock_bh(&s->tcf_lock);
212 opt.action = s->tcf_action;
213 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
214 goto nla_put_failure;
216 tcf_tm_dump(&t, &s->tcf_tm);
217 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
218 goto nla_put_failure;
220 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
221 goto nla_put_failure;
224 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
225 goto nla_put_failure;
227 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
228 goto nla_put_failure;
229 spin_unlock_bh(&s->tcf_lock);
234 spin_unlock_bh(&s->tcf_lock);
239 static int tcf_sample_walker(struct net *net, struct sk_buff *skb,
240 struct netlink_callback *cb, int type,
241 const struct tc_action_ops *ops,
242 struct netlink_ext_ack *extack)
244 struct tc_action_net *tn = net_generic(net, sample_net_id);
246 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
249 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
251 struct tc_action_net *tn = net_generic(net, sample_net_id);
253 return tcf_idr_search(tn, a, index);
256 static void tcf_psample_group_put(void *priv)
258 struct psample_group *group = priv;
260 psample_group_put(group);
263 static struct psample_group *
264 tcf_sample_get_group(const struct tc_action *a,
265 tc_action_priv_destructor *destructor)
267 struct tcf_sample *s = to_sample(a);
268 struct psample_group *group;
270 spin_lock_bh(&s->tcf_lock);
271 group = rcu_dereference_protected(s->psample_group,
272 lockdep_is_held(&s->tcf_lock));
274 psample_group_take(group);
275 *destructor = tcf_psample_group_put;
277 spin_unlock_bh(&s->tcf_lock);
282 static struct tc_action_ops act_sample_ops = {
285 .owner = THIS_MODULE,
286 .act = tcf_sample_act,
287 .dump = tcf_sample_dump,
288 .init = tcf_sample_init,
289 .cleanup = tcf_sample_cleanup,
290 .walk = tcf_sample_walker,
291 .lookup = tcf_sample_search,
292 .get_psample_group = tcf_sample_get_group,
293 .size = sizeof(struct tcf_sample),
296 static __net_init int sample_init_net(struct net *net)
298 struct tc_action_net *tn = net_generic(net, sample_net_id);
300 return tc_action_net_init(net, tn, &act_sample_ops);
303 static void __net_exit sample_exit_net(struct list_head *net_list)
305 tc_action_net_exit(net_list, sample_net_id);
308 static struct pernet_operations sample_net_ops = {
309 .init = sample_init_net,
310 .exit_batch = sample_exit_net,
311 .id = &sample_net_id,
312 .size = sizeof(struct tc_action_net),
315 static int __init sample_init_module(void)
317 return tcf_register_action(&act_sample_ops, &sample_net_ops);
320 static void __exit sample_cleanup_module(void)
322 tcf_unregister_action(&act_sample_ops, &sample_net_ops);
325 module_init(sample_init_module);
326 module_exit(sample_cleanup_module);
328 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
329 MODULE_DESCRIPTION("Packet sampling action");
330 MODULE_LICENSE("GPL v2");