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,
40 int bind, struct netlink_ext_ack *extack)
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;
52 ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL);
55 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] ||
56 !tb[TCA_SAMPLE_PSAMPLE_GROUP])
59 parm = nla_data(tb[TCA_SAMPLE_PARMS]);
61 exists = tcf_idr_check(tn, parm->index, a, bind);
66 ret = tcf_idr_create(tn, parm->index, est, a,
67 &act_sample_ops, bind, false);
72 tcf_idr_release(*a, bind);
78 s->tcf_action = parm->action;
79 s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
80 s->psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
81 psample_group = psample_group_get(net, s->psample_group_num);
83 if (ret == ACT_P_CREATED)
84 tcf_idr_release(*a, bind);
87 RCU_INIT_POINTER(s->psample_group, psample_group);
89 if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
91 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
94 if (ret == ACT_P_CREATED)
95 tcf_idr_insert(tn, *a);
99 static void tcf_sample_cleanup(struct tc_action *a)
101 struct tcf_sample *s = to_sample(a);
102 struct psample_group *psample_group;
104 psample_group = rtnl_dereference(s->psample_group);
105 RCU_INIT_POINTER(s->psample_group, NULL);
107 psample_group_put(psample_group);
110 static bool tcf_sample_dev_ok_push(struct net_device *dev)
125 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
126 struct tcf_result *res)
128 struct tcf_sample *s = to_sample(a);
129 struct psample_group *psample_group;
135 tcf_lastuse_update(&s->tcf_tm);
136 bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
137 retval = READ_ONCE(s->tcf_action);
140 psample_group = rcu_dereference(s->psample_group);
142 /* randomly sample packets according to rate */
143 if (psample_group && (prandom_u32() % s->rate == 0)) {
144 if (!skb_at_tc_ingress(skb)) {
146 oif = skb->dev->ifindex;
148 iif = skb->dev->ifindex;
152 /* on ingress, the mac header gets popped, so push it back */
153 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
154 skb_push(skb, skb->mac_len);
156 size = s->truncate ? s->trunc_size : skb->len;
157 psample_sample_packet(psample_group, skb, size, iif, oif,
160 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
161 skb_pull(skb, skb->mac_len);
168 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
171 unsigned char *b = skb_tail_pointer(skb);
172 struct tcf_sample *s = to_sample(a);
173 struct tc_sample opt = {
174 .index = s->tcf_index,
175 .action = s->tcf_action,
176 .refcnt = s->tcf_refcnt - ref,
177 .bindcnt = s->tcf_bindcnt - bind,
181 if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
182 goto nla_put_failure;
184 tcf_tm_dump(&t, &s->tcf_tm);
185 if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
186 goto nla_put_failure;
188 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
189 goto nla_put_failure;
192 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
193 goto nla_put_failure;
195 if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
196 goto nla_put_failure;
204 static int tcf_sample_walker(struct net *net, struct sk_buff *skb,
205 struct netlink_callback *cb, int type,
206 const struct tc_action_ops *ops,
207 struct netlink_ext_ack *extack)
209 struct tc_action_net *tn = net_generic(net, sample_net_id);
211 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
214 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index,
215 struct netlink_ext_ack *extack)
217 struct tc_action_net *tn = net_generic(net, sample_net_id);
219 return tcf_idr_search(tn, a, index);
222 static struct tc_action_ops act_sample_ops = {
224 .type = TCA_ACT_SAMPLE,
225 .owner = THIS_MODULE,
226 .act = tcf_sample_act,
227 .dump = tcf_sample_dump,
228 .init = tcf_sample_init,
229 .cleanup = tcf_sample_cleanup,
230 .walk = tcf_sample_walker,
231 .lookup = tcf_sample_search,
232 .size = sizeof(struct tcf_sample),
235 static __net_init int sample_init_net(struct net *net)
237 struct tc_action_net *tn = net_generic(net, sample_net_id);
239 return tc_action_net_init(tn, &act_sample_ops);
242 static void __net_exit sample_exit_net(struct list_head *net_list)
244 tc_action_net_exit(net_list, sample_net_id);
247 static struct pernet_operations sample_net_ops = {
248 .init = sample_init_net,
249 .exit_batch = sample_exit_net,
250 .id = &sample_net_id,
251 .size = sizeof(struct tc_action_net),
255 static int __init sample_init_module(void)
257 return tcf_register_action(&act_sample_ops, &sample_net_ops);
260 static void __exit sample_cleanup_module(void)
262 tcf_unregister_action(&act_sample_ops, &sample_net_ops);
265 module_init(sample_init_module);
266 module_exit(sample_cleanup_module);
268 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
269 MODULE_DESCRIPTION("Packet sampling action");
270 MODULE_LICENSE("GPL v2");