2 * net/sched/act_sample.c - Packet sampling tc action
3 * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
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 <net/net_namespace.h>
20 #include <net/netlink.h>
21 #include <net/pkt_sched.h>
22 #include <linux/tc_act/tc_sample.h>
23 #include <net/tc_act/tc_sample.h>
24 #include <net/psample.h>
26 #include <linux/if_arp.h>
28 static unsigned int sample_net_id;
29 static struct tc_action_ops act_sample_ops;
31 static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = {
32 [TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) },
33 [TCA_SAMPLE_RATE] = { .type = NLA_U32 },
34 [TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 },
35 [TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 },
38 static int tcf_sample_init(struct net *net, struct nlattr *nla,
39 struct nlattr *est, struct tc_action **a, int ovr,
42 struct tc_action_net *tn = net_generic(net, sample_net_id);
43 struct nlattr *tb[TCA_SAMPLE_MAX + 1];
44 struct psample_group *psample_group;
45 struct tc_sample *parm;
53 ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL);
56 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] ||
57 !tb[TCA_SAMPLE_PSAMPLE_GROUP])
60 parm = nla_data(tb[TCA_SAMPLE_PARMS]);
62 exists = tcf_idr_check(tn, parm->index, a, bind);
67 ret = tcf_idr_create(tn, parm->index, est, a,
68 &act_sample_ops, bind, true);
73 tcf_idr_release(*a, bind);
78 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
80 tcf_idr_release(*a, bind);
85 s->tcf_action = parm->action;
86 s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
88 s->psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
89 psample_group = psample_group_get(net, s->psample_group_num);
91 if (ret == ACT_P_CREATED)
92 tcf_idr_release(*a, bind);
95 rcu_swap_protected(s->psample_group, psample_group,
96 lockdep_is_held(&s->tcf_lock));
98 if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
100 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
104 psample_group_put(psample_group);
105 if (ret == ACT_P_CREATED)
106 tcf_idr_insert(tn, *a);
110 static void tcf_sample_cleanup_rcu(struct rcu_head *rcu)
112 struct tcf_sample *s = container_of(rcu, struct tcf_sample, rcu);
113 struct psample_group *psample_group;
115 psample_group = rcu_dereference_protected(s->psample_group, 1);
116 RCU_INIT_POINTER(s->psample_group, NULL);
118 psample_group_put(psample_group);
121 static void tcf_sample_cleanup(struct tc_action *a, int bind)
123 struct tcf_sample *s = to_sample(a);
125 call_rcu(&s->rcu, tcf_sample_cleanup_rcu);
128 static bool tcf_sample_dev_ok_push(struct net_device *dev)
144 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
145 struct tcf_result *res)
147 struct tcf_sample *s = to_sample(a);
148 struct psample_group *psample_group;
154 tcf_lastuse_update(&s->tcf_tm);
155 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
156 retval = READ_ONCE(s->tcf_action);
159 psample_group = rcu_dereference(s->psample_group);
161 /* randomly sample packets according to rate */
162 if (psample_group && (prandom_u32() % s->rate == 0)) {
163 if (!skb_at_tc_ingress(skb)) {
165 oif = skb->dev->ifindex;
167 iif = skb->dev->ifindex;
171 /* on ingress, the mac header gets popped, so push it back */
172 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
173 skb_push(skb, skb->mac_len);
175 size = s->truncate ? s->trunc_size : skb->len;
176 psample_sample_packet(psample_group, skb, size, iif, oif,
179 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
180 skb_pull(skb, skb->mac_len);
187 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
190 unsigned char *b = skb_tail_pointer(skb);
191 struct tcf_sample *s = to_sample(a);
192 struct tc_sample opt = {
193 .index = s->tcf_index,
194 .action = s->tcf_action,
195 .refcnt = s->tcf_refcnt - ref,
196 .bindcnt = s->tcf_bindcnt - bind,
200 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
201 goto nla_put_failure;
203 tcf_tm_dump(&t, &s->tcf_tm);
204 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
205 goto nla_put_failure;
207 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
208 goto nla_put_failure;
211 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
212 goto nla_put_failure;
214 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
215 goto nla_put_failure;
223 static int tcf_sample_walker(struct net *net, struct sk_buff *skb,
224 struct netlink_callback *cb, int type,
225 const struct tc_action_ops *ops)
227 struct tc_action_net *tn = net_generic(net, sample_net_id);
229 return tcf_generic_walker(tn, skb, cb, type, ops);
232 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
234 struct tc_action_net *tn = net_generic(net, sample_net_id);
236 return tcf_idr_search(tn, a, index);
239 static struct tc_action_ops act_sample_ops = {
241 .type = TCA_ACT_SAMPLE,
242 .owner = THIS_MODULE,
243 .act = tcf_sample_act,
244 .dump = tcf_sample_dump,
245 .init = tcf_sample_init,
246 .cleanup = tcf_sample_cleanup,
247 .walk = tcf_sample_walker,
248 .lookup = tcf_sample_search,
249 .size = sizeof(struct tcf_sample),
252 static __net_init int sample_init_net(struct net *net)
254 struct tc_action_net *tn = net_generic(net, sample_net_id);
256 return tc_action_net_init(net, tn, &act_sample_ops);
259 static void __net_exit sample_exit_net(struct net *net)
261 struct tc_action_net *tn = net_generic(net, sample_net_id);
263 tc_action_net_exit(tn);
266 static struct pernet_operations sample_net_ops = {
267 .init = sample_init_net,
268 .exit = sample_exit_net,
269 .id = &sample_net_id,
270 .size = sizeof(struct tc_action_net),
273 static int __init sample_init_module(void)
275 return tcf_register_action(&act_sample_ops, &sample_net_ops);
278 static void __exit sample_cleanup_module(void)
281 tcf_unregister_action(&act_sample_ops, &sample_net_ops);
284 module_init(sample_init_module);
285 module_exit(sample_cleanup_module);
287 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
288 MODULE_DESCRIPTION("Packet sampling action");
289 MODULE_LICENSE("GPL v2");