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 struct tc_sample *parm;
49 u32 psample_group_num;
56 ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL);
59 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] ||
60 !tb[TCA_SAMPLE_PSAMPLE_GROUP])
63 parm = nla_data(tb[TCA_SAMPLE_PARMS]);
65 err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
73 ret = tcf_idr_create(tn, parm->index, est, a,
74 &act_sample_ops, bind, true);
76 tcf_idr_cleanup(tn, parm->index);
81 tcf_idr_release(*a, bind);
84 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
88 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
89 psample_group = psample_group_get(net, psample_group_num);
97 spin_lock_bh(&s->tcf_lock);
98 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
99 s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
100 s->psample_group_num = psample_group_num;
101 RCU_INIT_POINTER(s->psample_group, psample_group);
103 if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
105 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
107 spin_unlock_bh(&s->tcf_lock);
109 tcf_chain_put_by_act(goto_ch);
111 if (ret == ACT_P_CREATED)
112 tcf_idr_insert(tn, *a);
116 tcf_chain_put_by_act(goto_ch);
118 tcf_idr_release(*a, bind);
122 static void tcf_sample_cleanup(struct tc_action *a)
124 struct tcf_sample *s = to_sample(a);
125 struct psample_group *psample_group;
127 /* last reference to action, no need to lock */
128 psample_group = rcu_dereference_protected(s->psample_group, 1);
129 RCU_INIT_POINTER(s->psample_group, NULL);
131 psample_group_put(psample_group);
134 static bool tcf_sample_dev_ok_push(struct net_device *dev)
149 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
150 struct tcf_result *res)
152 struct tcf_sample *s = to_sample(a);
153 struct psample_group *psample_group;
159 tcf_lastuse_update(&s->tcf_tm);
160 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
161 retval = READ_ONCE(s->tcf_action);
163 psample_group = rcu_dereference_bh(s->psample_group);
165 /* randomly sample packets according to rate */
166 if (psample_group && (prandom_u32() % s->rate == 0)) {
167 if (!skb_at_tc_ingress(skb)) {
169 oif = skb->dev->ifindex;
171 iif = skb->dev->ifindex;
175 /* on ingress, the mac header gets popped, so push it back */
176 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
177 skb_push(skb, skb->mac_len);
179 size = s->truncate ? s->trunc_size : skb->len;
180 psample_sample_packet(psample_group, skb, size, iif, oif,
183 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
184 skb_pull(skb, skb->mac_len);
190 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
193 unsigned char *b = skb_tail_pointer(skb);
194 struct tcf_sample *s = to_sample(a);
195 struct tc_sample opt = {
196 .index = s->tcf_index,
197 .refcnt = refcount_read(&s->tcf_refcnt) - ref,
198 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind,
202 spin_lock_bh(&s->tcf_lock);
203 opt.action = s->tcf_action;
204 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
205 goto nla_put_failure;
207 tcf_tm_dump(&t, &s->tcf_tm);
208 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
209 goto nla_put_failure;
211 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
212 goto nla_put_failure;
215 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
216 goto nla_put_failure;
218 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
219 goto nla_put_failure;
220 spin_unlock_bh(&s->tcf_lock);
225 spin_unlock_bh(&s->tcf_lock);
230 static int tcf_sample_walker(struct net *net, struct sk_buff *skb,
231 struct netlink_callback *cb, int type,
232 const struct tc_action_ops *ops,
233 struct netlink_ext_ack *extack)
235 struct tc_action_net *tn = net_generic(net, sample_net_id);
237 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
240 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
242 struct tc_action_net *tn = net_generic(net, sample_net_id);
244 return tcf_idr_search(tn, a, index);
247 static struct tc_action_ops act_sample_ops = {
250 .owner = THIS_MODULE,
251 .act = tcf_sample_act,
252 .dump = tcf_sample_dump,
253 .init = tcf_sample_init,
254 .cleanup = tcf_sample_cleanup,
255 .walk = tcf_sample_walker,
256 .lookup = tcf_sample_search,
257 .size = sizeof(struct tcf_sample),
260 static __net_init int sample_init_net(struct net *net)
262 struct tc_action_net *tn = net_generic(net, sample_net_id);
264 return tc_action_net_init(tn, &act_sample_ops);
267 static void __net_exit sample_exit_net(struct list_head *net_list)
269 tc_action_net_exit(net_list, sample_net_id);
272 static struct pernet_operations sample_net_ops = {
273 .init = sample_init_net,
274 .exit_batch = sample_exit_net,
275 .id = &sample_net_id,
276 .size = sizeof(struct tc_action_net),
279 static int __init sample_init_module(void)
281 return tcf_register_action(&act_sample_ops, &sample_net_ops);
284 static void __exit sample_cleanup_module(void)
286 tcf_unregister_action(&act_sample_ops, &sample_net_ops);
289 module_init(sample_init_module);
290 module_exit(sample_cleanup_module);
292 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
293 MODULE_DESCRIPTION("Packet sampling action");
294 MODULE_LICENSE("GPL v2");