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5c5670fa YG |
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 | ||
26 | #include <linux/if_arp.h> | |
27 | ||
5c5670fa YG |
28 | static unsigned int sample_net_id; |
29 | static struct tc_action_ops act_sample_ops; | |
30 | ||
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 }, | |
36 | }; | |
37 | ||
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) | |
41 | { | |
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; | |
46 | struct tcf_sample *s; | |
47 | bool exists = false; | |
48 | int ret; | |
49 | ||
50 | if (!nla) | |
51 | return -EINVAL; | |
fceb6435 | 52 | ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL); |
5c5670fa YG |
53 | if (ret < 0) |
54 | return ret; | |
55 | if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] || | |
56 | !tb[TCA_SAMPLE_PSAMPLE_GROUP]) | |
57 | return -EINVAL; | |
58 | ||
59 | parm = nla_data(tb[TCA_SAMPLE_PARMS]); | |
60 | ||
65a206c0 | 61 | exists = tcf_idr_check(tn, parm->index, a, bind); |
5c5670fa YG |
62 | if (exists && bind) |
63 | return 0; | |
64 | ||
65 | if (!exists) { | |
65a206c0 CM |
66 | ret = tcf_idr_create(tn, parm->index, est, a, |
67 | &act_sample_ops, bind, false); | |
5c5670fa YG |
68 | if (ret) |
69 | return ret; | |
70 | ret = ACT_P_CREATED; | |
71 | } else { | |
65a206c0 | 72 | tcf_idr_release(*a, bind); |
5c5670fa YG |
73 | if (!ovr) |
74 | return -EEXIST; | |
75 | } | |
76 | s = to_sample(*a); | |
77 | ||
5c5670fa YG |
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); | |
cadb9c9f YG |
82 | if (!psample_group) { |
83 | if (ret == ACT_P_CREATED) | |
65a206c0 | 84 | tcf_idr_release(*a, bind); |
5c5670fa | 85 | return -ENOMEM; |
cadb9c9f | 86 | } |
5c5670fa YG |
87 | RCU_INIT_POINTER(s->psample_group, psample_group); |
88 | ||
89 | if (tb[TCA_SAMPLE_TRUNC_SIZE]) { | |
90 | s->truncate = true; | |
91 | s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); | |
92 | } | |
93 | ||
94 | if (ret == ACT_P_CREATED) | |
65a206c0 | 95 | tcf_idr_insert(tn, *a); |
5c5670fa YG |
96 | return ret; |
97 | } | |
98 | ||
99 | static void tcf_sample_cleanup_rcu(struct rcu_head *rcu) | |
100 | { | |
101 | struct tcf_sample *s = container_of(rcu, struct tcf_sample, rcu); | |
102 | struct psample_group *psample_group; | |
103 | ||
104 | psample_group = rcu_dereference_protected(s->psample_group, 1); | |
105 | RCU_INIT_POINTER(s->psample_group, NULL); | |
106 | psample_group_put(psample_group); | |
107 | } | |
108 | ||
109 | static void tcf_sample_cleanup(struct tc_action *a, int bind) | |
110 | { | |
111 | struct tcf_sample *s = to_sample(a); | |
112 | ||
113 | call_rcu(&s->rcu, tcf_sample_cleanup_rcu); | |
114 | } | |
115 | ||
116 | static bool tcf_sample_dev_ok_push(struct net_device *dev) | |
117 | { | |
118 | switch (dev->type) { | |
119 | case ARPHRD_TUNNEL: | |
120 | case ARPHRD_TUNNEL6: | |
121 | case ARPHRD_SIT: | |
122 | case ARPHRD_IPGRE: | |
123 | case ARPHRD_VOID: | |
124 | case ARPHRD_NONE: | |
125 | return false; | |
126 | default: | |
127 | return true; | |
128 | } | |
129 | } | |
130 | ||
131 | static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, | |
132 | struct tcf_result *res) | |
133 | { | |
134 | struct tcf_sample *s = to_sample(a); | |
135 | struct psample_group *psample_group; | |
136 | int retval; | |
137 | int size; | |
138 | int iif; | |
139 | int oif; | |
140 | ||
141 | tcf_lastuse_update(&s->tcf_tm); | |
142 | bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); | |
143 | retval = READ_ONCE(s->tcf_action); | |
144 | ||
145 | rcu_read_lock(); | |
146 | psample_group = rcu_dereference(s->psample_group); | |
147 | ||
148 | /* randomly sample packets according to rate */ | |
149 | if (psample_group && (prandom_u32() % s->rate == 0)) { | |
150 | if (!skb_at_tc_ingress(skb)) { | |
151 | iif = skb->skb_iif; | |
152 | oif = skb->dev->ifindex; | |
153 | } else { | |
154 | iif = skb->dev->ifindex; | |
155 | oif = 0; | |
156 | } | |
157 | ||
158 | /* on ingress, the mac header gets popped, so push it back */ | |
159 | if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) | |
160 | skb_push(skb, skb->mac_len); | |
161 | ||
162 | size = s->truncate ? s->trunc_size : skb->len; | |
163 | psample_sample_packet(psample_group, skb, size, iif, oif, | |
164 | s->rate); | |
165 | ||
166 | if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) | |
167 | skb_pull(skb, skb->mac_len); | |
168 | } | |
169 | ||
170 | rcu_read_unlock(); | |
171 | return retval; | |
172 | } | |
173 | ||
174 | static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, | |
175 | int bind, int ref) | |
176 | { | |
177 | unsigned char *b = skb_tail_pointer(skb); | |
178 | struct tcf_sample *s = to_sample(a); | |
179 | struct tc_sample opt = { | |
180 | .index = s->tcf_index, | |
181 | .action = s->tcf_action, | |
182 | .refcnt = s->tcf_refcnt - ref, | |
183 | .bindcnt = s->tcf_bindcnt - bind, | |
184 | }; | |
185 | struct tcf_t t; | |
186 | ||
187 | if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) | |
188 | goto nla_put_failure; | |
189 | ||
190 | tcf_tm_dump(&t, &s->tcf_tm); | |
191 | if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) | |
192 | goto nla_put_failure; | |
193 | ||
194 | if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) | |
195 | goto nla_put_failure; | |
196 | ||
197 | if (s->truncate) | |
198 | if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) | |
199 | goto nla_put_failure; | |
200 | ||
201 | if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) | |
202 | goto nla_put_failure; | |
203 | return skb->len; | |
204 | ||
205 | nla_put_failure: | |
206 | nlmsg_trim(skb, b); | |
207 | return -1; | |
208 | } | |
209 | ||
210 | static int tcf_sample_walker(struct net *net, struct sk_buff *skb, | |
211 | struct netlink_callback *cb, int type, | |
212 | const struct tc_action_ops *ops) | |
213 | { | |
214 | struct tc_action_net *tn = net_generic(net, sample_net_id); | |
215 | ||
216 | return tcf_generic_walker(tn, skb, cb, type, ops); | |
217 | } | |
218 | ||
219 | static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index) | |
220 | { | |
221 | struct tc_action_net *tn = net_generic(net, sample_net_id); | |
222 | ||
65a206c0 | 223 | return tcf_idr_search(tn, a, index); |
5c5670fa YG |
224 | } |
225 | ||
226 | static struct tc_action_ops act_sample_ops = { | |
227 | .kind = "sample", | |
228 | .type = TCA_ACT_SAMPLE, | |
229 | .owner = THIS_MODULE, | |
230 | .act = tcf_sample_act, | |
231 | .dump = tcf_sample_dump, | |
232 | .init = tcf_sample_init, | |
233 | .cleanup = tcf_sample_cleanup, | |
234 | .walk = tcf_sample_walker, | |
235 | .lookup = tcf_sample_search, | |
236 | .size = sizeof(struct tcf_sample), | |
237 | }; | |
238 | ||
239 | static __net_init int sample_init_net(struct net *net) | |
240 | { | |
241 | struct tc_action_net *tn = net_generic(net, sample_net_id); | |
242 | ||
c7e460ce | 243 | return tc_action_net_init(tn, &act_sample_ops); |
5c5670fa YG |
244 | } |
245 | ||
246 | static void __net_exit sample_exit_net(struct net *net) | |
247 | { | |
248 | struct tc_action_net *tn = net_generic(net, sample_net_id); | |
249 | ||
250 | tc_action_net_exit(tn); | |
251 | } | |
252 | ||
253 | static struct pernet_operations sample_net_ops = { | |
254 | .init = sample_init_net, | |
255 | .exit = sample_exit_net, | |
256 | .id = &sample_net_id, | |
257 | .size = sizeof(struct tc_action_net), | |
258 | }; | |
259 | ||
260 | static int __init sample_init_module(void) | |
261 | { | |
262 | return tcf_register_action(&act_sample_ops, &sample_net_ops); | |
263 | } | |
264 | ||
265 | static void __exit sample_cleanup_module(void) | |
266 | { | |
46e235c1 | 267 | rcu_barrier(); |
5c5670fa YG |
268 | tcf_unregister_action(&act_sample_ops, &sample_net_ops); |
269 | } | |
270 | ||
271 | module_init(sample_init_module); | |
272 | module_exit(sample_cleanup_module); | |
273 | ||
f1fd20c3 | 274 | MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); |
5c5670fa YG |
275 | MODULE_DESCRIPTION("Packet sampling action"); |
276 | MODULE_LICENSE("GPL v2"); |