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>
25 #include <net/pkt_cls.h>
27 #include <linux/if_arp.h>
29 static unsigned int sample_net_id;
30 static struct tc_action_ops act_sample_ops;
32 static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = {
33 [TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) },
34 [TCA_SAMPLE_RATE] = { .type = NLA_U32 },
35 [TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 },
36 [TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 },
39 static int tcf_sample_init(struct net *net, struct nlattr *nla,
40 struct nlattr *est, struct tc_action **a, int ovr,
41 int bind, bool rtnl_held, struct tcf_proto *tp,
42 struct netlink_ext_ack *extack)
44 struct tc_action_net *tn = net_generic(net, sample_net_id);
45 struct nlattr *tb[TCA_SAMPLE_MAX + 1];
46 struct psample_group *psample_group;
47 struct tcf_chain *goto_ch = NULL;
48 u32 psample_group_num, rate;
49 struct tc_sample *parm;
56 ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla,
60 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] ||
61 !tb[TCA_SAMPLE_PSAMPLE_GROUP])
64 parm = nla_data(tb[TCA_SAMPLE_PARMS]);
66 err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
74 ret = tcf_idr_create(tn, parm->index, est, a,
75 &act_sample_ops, bind, true);
77 tcf_idr_cleanup(tn, parm->index);
82 tcf_idr_release(*a, bind);
85 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
89 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
91 NL_SET_ERR_MSG(extack, "invalid sample rate");
95 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
96 psample_group = psample_group_get(net, psample_group_num);
104 spin_lock_bh(&s->tcf_lock);
105 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
107 s->psample_group_num = psample_group_num;
108 RCU_INIT_POINTER(s->psample_group, psample_group);
110 if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
112 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
114 spin_unlock_bh(&s->tcf_lock);
116 tcf_chain_put_by_act(goto_ch);
118 if (ret == ACT_P_CREATED)
119 tcf_idr_insert(tn, *a);
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)
156 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
157 struct tcf_result *res)
159 struct tcf_sample *s = to_sample(a);
160 struct psample_group *psample_group;
166 tcf_lastuse_update(&s->tcf_tm);
167 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
168 retval = READ_ONCE(s->tcf_action);
170 psample_group = rcu_dereference_bh(s->psample_group);
172 /* randomly sample packets according to rate */
173 if (psample_group && (prandom_u32() % s->rate == 0)) {
174 if (!skb_at_tc_ingress(skb)) {
176 oif = skb->dev->ifindex;
178 iif = skb->dev->ifindex;
182 /* on ingress, the mac header gets popped, so push it back */
183 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
184 skb_push(skb, skb->mac_len);
186 size = s->truncate ? s->trunc_size : skb->len;
187 psample_sample_packet(psample_group, skb, size, iif, oif,
190 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
191 skb_pull(skb, skb->mac_len);
197 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
200 unsigned char *b = skb_tail_pointer(skb);
201 struct tcf_sample *s = to_sample(a);
202 struct tc_sample opt = {
203 .index = s->tcf_index,
204 .refcnt = refcount_read(&s->tcf_refcnt) - ref,
205 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind,
209 spin_lock_bh(&s->tcf_lock);
210 opt.action = s->tcf_action;
211 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
212 goto nla_put_failure;
214 tcf_tm_dump(&t, &s->tcf_tm);
215 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
216 goto nla_put_failure;
218 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
219 goto nla_put_failure;
222 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
223 goto nla_put_failure;
225 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
226 goto nla_put_failure;
227 spin_unlock_bh(&s->tcf_lock);
232 spin_unlock_bh(&s->tcf_lock);
237 static int tcf_sample_walker(struct net *net, struct sk_buff *skb,
238 struct netlink_callback *cb, int type,
239 const struct tc_action_ops *ops,
240 struct netlink_ext_ack *extack)
242 struct tc_action_net *tn = net_generic(net, sample_net_id);
244 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
247 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
249 struct tc_action_net *tn = net_generic(net, sample_net_id);
251 return tcf_idr_search(tn, a, index);
254 static struct tc_action_ops act_sample_ops = {
257 .owner = THIS_MODULE,
258 .act = tcf_sample_act,
259 .dump = tcf_sample_dump,
260 .init = tcf_sample_init,
261 .cleanup = tcf_sample_cleanup,
262 .walk = tcf_sample_walker,
263 .lookup = tcf_sample_search,
264 .size = sizeof(struct tcf_sample),
267 static __net_init int sample_init_net(struct net *net)
269 struct tc_action_net *tn = net_generic(net, sample_net_id);
271 return tc_action_net_init(tn, &act_sample_ops);
274 static void __net_exit sample_exit_net(struct list_head *net_list)
276 tc_action_net_exit(net_list, sample_net_id);
279 static struct pernet_operations sample_net_ops = {
280 .init = sample_init_net,
281 .exit_batch = sample_exit_net,
282 .id = &sample_net_id,
283 .size = sizeof(struct tc_action_net),
286 static int __init sample_init_module(void)
288 return tcf_register_action(&act_sample_ops, &sample_net_ops);
291 static void __exit sample_cleanup_module(void)
293 tcf_unregister_action(&act_sample_ops, &sample_net_ops);
296 module_init(sample_init_module);
297 module_exit(sample_cleanup_module);
299 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
300 MODULE_DESCRIPTION("Packet sampling action");
301 MODULE_LICENSE("GPL v2");