Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * net/sched/act_sample.c - Packet sampling tc action
3 * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
4 *
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.
8 */
9
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>
26
27#include <linux/if_arp.h>
28
29static unsigned int sample_net_id;
30static struct tc_action_ops act_sample_ops;
31
32static 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 },
37};
38
39static 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)
43{
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;
50 struct tcf_sample *s;
51 bool exists = false;
52 int ret, err;
53
54 if (!nla)
55 return -EINVAL;
56 ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL);
57 if (ret < 0)
58 return ret;
59 if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] ||
60 !tb[TCA_SAMPLE_PSAMPLE_GROUP])
61 return -EINVAL;
62
63 parm = nla_data(tb[TCA_SAMPLE_PARMS]);
64
65 err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
66 if (err < 0)
67 return err;
68 exists = err;
69 if (exists && bind)
70 return 0;
71
72 if (!exists) {
73 ret = tcf_idr_create(tn, parm->index, est, a,
74 &act_sample_ops, bind, true);
75 if (ret) {
76 tcf_idr_cleanup(tn, parm->index);
77 return ret;
78 }
79 ret = ACT_P_CREATED;
80 } else if (!ovr) {
81 tcf_idr_release(*a, bind);
82 return -EEXIST;
83 }
84 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
85 if (err < 0)
86 goto release_idr;
87
88 rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
89 if (!rate) {
90 NL_SET_ERR_MSG(extack, "invalid sample rate");
91 err = -EINVAL;
92 goto put_chain;
93 }
94 psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
95 psample_group = psample_group_get(net, psample_group_num);
96 if (!psample_group) {
97 err = -ENOMEM;
98 goto put_chain;
99 }
100
101 s = to_sample(*a);
102
103 spin_lock_bh(&s->tcf_lock);
104 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
105 s->rate = rate;
106 s->psample_group_num = psample_group_num;
107 RCU_INIT_POINTER(s->psample_group, psample_group);
108
109 if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
110 s->truncate = true;
111 s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
112 }
113 spin_unlock_bh(&s->tcf_lock);
114 if (goto_ch)
115 tcf_chain_put_by_act(goto_ch);
116
117 if (ret == ACT_P_CREATED)
118 tcf_idr_insert(tn, *a);
119 return ret;
120put_chain:
121 if (goto_ch)
122 tcf_chain_put_by_act(goto_ch);
123release_idr:
124 tcf_idr_release(*a, bind);
125 return err;
126}
127
128static void tcf_sample_cleanup(struct tc_action *a)
129{
130 struct tcf_sample *s = to_sample(a);
131 struct psample_group *psample_group;
132
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);
136 if (psample_group)
137 psample_group_put(psample_group);
138}
139
140static bool tcf_sample_dev_ok_push(struct net_device *dev)
141{
142 switch (dev->type) {
143 case ARPHRD_TUNNEL:
144 case ARPHRD_TUNNEL6:
145 case ARPHRD_SIT:
146 case ARPHRD_IPGRE:
147 case ARPHRD_VOID:
148 case ARPHRD_NONE:
149 return false;
150 default:
151 return true;
152 }
153}
154
155static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
156 struct tcf_result *res)
157{
158 struct tcf_sample *s = to_sample(a);
159 struct psample_group *psample_group;
160 int retval;
161 int size;
162 int iif;
163 int oif;
164
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);
168
169 psample_group = rcu_dereference_bh(s->psample_group);
170
171 /* randomly sample packets according to rate */
172 if (psample_group && (prandom_u32() % s->rate == 0)) {
173 if (!skb_at_tc_ingress(skb)) {
174 iif = skb->skb_iif;
175 oif = skb->dev->ifindex;
176 } else {
177 iif = skb->dev->ifindex;
178 oif = 0;
179 }
180
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);
184
185 size = s->truncate ? s->trunc_size : skb->len;
186 psample_sample_packet(psample_group, skb, size, iif, oif,
187 s->rate);
188
189 if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
190 skb_pull(skb, skb->mac_len);
191 }
192
193 return retval;
194}
195
196static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
197 int bind, int ref)
198{
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,
205 };
206 struct tcf_t t;
207
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;
212
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;
216
217 if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
218 goto nla_put_failure;
219
220 if (s->truncate)
221 if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
222 goto nla_put_failure;
223
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);
227
228 return skb->len;
229
230nla_put_failure:
231 spin_unlock_bh(&s->tcf_lock);
232 nlmsg_trim(skb, b);
233 return -1;
234}
235
236static 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)
240{
241 struct tc_action_net *tn = net_generic(net, sample_net_id);
242
243 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
244}
245
246static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
247{
248 struct tc_action_net *tn = net_generic(net, sample_net_id);
249
250 return tcf_idr_search(tn, a, index);
251}
252
253static struct tc_action_ops act_sample_ops = {
254 .kind = "sample",
255 .id = TCA_ID_SAMPLE,
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),
264};
265
266static __net_init int sample_init_net(struct net *net)
267{
268 struct tc_action_net *tn = net_generic(net, sample_net_id);
269
270 return tc_action_net_init(tn, &act_sample_ops);
271}
272
273static void __net_exit sample_exit_net(struct list_head *net_list)
274{
275 tc_action_net_exit(net_list, sample_net_id);
276}
277
278static 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),
283};
284
285static int __init sample_init_module(void)
286{
287 return tcf_register_action(&act_sample_ops, &sample_net_ops);
288}
289
290static void __exit sample_cleanup_module(void)
291{
292 tcf_unregister_action(&act_sample_ops, &sample_net_ops);
293}
294
295module_init(sample_init_module);
296module_exit(sample_cleanup_module);
297
298MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
299MODULE_DESCRIPTION("Packet sampling action");
300MODULE_LICENSE("GPL v2");