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(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 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
90 NL_SET_ERR_MSG(extack, "invalid sample rate");
94 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
95 psample_group = psample_group_get(net, psample_group_num);
103 spin_lock_bh(&s->tcf_lock);
104 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
106 s->psample_group_num = psample_group_num;
107 RCU_INIT_POINTER(s->psample_group, psample_group);
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);
115 tcf_chain_put_by_act(goto_ch);
117 if (ret == ACT_P_CREATED)
118 tcf_idr_insert(tn, *a);
122 tcf_chain_put_by_act(goto_ch);
124 tcf_idr_release(*a, bind);
128 static void tcf_sample_cleanup(struct tc_action *a)
130 struct tcf_sample *s = to_sample(a);
131 struct psample_group *psample_group;
133 /* last reference to action, no need to lock */
134 psample_group = rcu_dereference_protected(s->psample_group, 1);
135 RCU_INIT_POINTER(s->psample_group, NULL);
137 psample_group_put(psample_group);
140 static bool tcf_sample_dev_ok_push(struct net_device *dev)
155 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
156 struct tcf_result *res)
158 struct tcf_sample *s = to_sample(a);
159 struct psample_group *psample_group;
165 tcf_lastuse_update(&s->tcf_tm);
166 bstats_cpu_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)) {
175 oif = skb->dev->ifindex;
177 iif = skb->dev->ifindex;
181 /* on ingress, the mac header gets popped, so push it back */
182 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
183 skb_push(skb, skb->mac_len);
185 size = s->truncate ? s->trunc_size : skb->len;
186 psample_sample_packet(psample_group, skb, size, iif, oif,
189 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
190 skb_pull(skb, skb->mac_len);
196 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
199 unsigned char *b = skb_tail_pointer(skb);
200 struct tcf_sample *s = to_sample(a);
201 struct tc_sample opt = {
202 .index = s->tcf_index,
203 .refcnt = refcount_read(&s->tcf_refcnt) - ref,
204 .bindcnt = atomic_read(&s->tcf_bindcnt) - bind,
208 spin_lock_bh(&s->tcf_lock);
209 opt.action = s->tcf_action;
210 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
211 goto nla_put_failure;
213 tcf_tm_dump(&t, &s->tcf_tm);
214 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
215 goto nla_put_failure;
217 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
218 goto nla_put_failure;
221 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
222 goto nla_put_failure;
224 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
225 goto nla_put_failure;
226 spin_unlock_bh(&s->tcf_lock);
231 spin_unlock_bh(&s->tcf_lock);
236 static int tcf_sample_walker(struct net *net, struct sk_buff *skb,
237 struct netlink_callback *cb, int type,
238 const struct tc_action_ops *ops,
239 struct netlink_ext_ack *extack)
241 struct tc_action_net *tn = net_generic(net, sample_net_id);
243 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
246 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
248 struct tc_action_net *tn = net_generic(net, sample_net_id);
250 return tcf_idr_search(tn, a, index);
253 static struct tc_action_ops act_sample_ops = {
256 .owner = THIS_MODULE,
257 .act = tcf_sample_act,
258 .dump = tcf_sample_dump,
259 .init = tcf_sample_init,
260 .cleanup = tcf_sample_cleanup,
261 .walk = tcf_sample_walker,
262 .lookup = tcf_sample_search,
263 .size = sizeof(struct tcf_sample),
266 static __net_init int sample_init_net(struct net *net)
268 struct tc_action_net *tn = net_generic(net, sample_net_id);
270 return tc_action_net_init(tn, &act_sample_ops);
273 static void __net_exit sample_exit_net(struct list_head *net_list)
275 tc_action_net_exit(net_list, sample_net_id);
278 static struct pernet_operations sample_net_ops = {
279 .init = sample_init_net,
280 .exit_batch = sample_exit_net,
281 .id = &sample_net_id,
282 .size = sizeof(struct tc_action_net),
285 static int __init sample_init_module(void)
287 return tcf_register_action(&act_sample_ops, &sample_net_ops);
290 static void __exit sample_cleanup_module(void)
292 tcf_unregister_action(&act_sample_ops, &sample_net_ops);
295 module_init(sample_init_module);
296 module_exit(sample_cleanup_module);
298 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
299 MODULE_DESCRIPTION("Packet sampling action");
300 MODULE_LICENSE("GPL v2");