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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 | ||
28 | #define SAMPLE_TAB_MASK 7 | |
29 | static unsigned int sample_net_id; | |
30 | static struct tc_action_ops act_sample_ops; | |
31 | ||
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 }, | |
37 | }; | |
38 | ||
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) | |
42 | { | |
43 | struct tc_action_net *tn = net_generic(net, sample_net_id); | |
44 | struct nlattr *tb[TCA_SAMPLE_MAX + 1]; | |
45 | struct psample_group *psample_group; | |
46 | struct tc_sample *parm; | |
47 | struct tcf_sample *s; | |
48 | bool exists = false; | |
49 | int ret; | |
50 | ||
51 | if (!nla) | |
52 | return -EINVAL; | |
fceb6435 | 53 | ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL); |
5c5670fa YG |
54 | if (ret < 0) |
55 | return ret; | |
56 | if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] || | |
57 | !tb[TCA_SAMPLE_PSAMPLE_GROUP]) | |
58 | return -EINVAL; | |
59 | ||
60 | parm = nla_data(tb[TCA_SAMPLE_PARMS]); | |
61 | ||
62 | exists = tcf_hash_check(tn, parm->index, a, bind); | |
63 | if (exists && bind) | |
64 | return 0; | |
65 | ||
66 | if (!exists) { | |
67 | ret = tcf_hash_create(tn, parm->index, est, a, | |
68 | &act_sample_ops, bind, false); | |
69 | if (ret) | |
70 | return ret; | |
71 | ret = ACT_P_CREATED; | |
72 | } else { | |
73 | tcf_hash_release(*a, bind); | |
74 | if (!ovr) | |
75 | return -EEXIST; | |
76 | } | |
77 | s = to_sample(*a); | |
78 | ||
5c5670fa YG |
79 | s->tcf_action = parm->action; |
80 | s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); | |
81 | s->psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); | |
82 | psample_group = psample_group_get(net, s->psample_group_num); | |
cadb9c9f YG |
83 | if (!psample_group) { |
84 | if (ret == ACT_P_CREATED) | |
85 | tcf_hash_release(*a, bind); | |
5c5670fa | 86 | return -ENOMEM; |
cadb9c9f | 87 | } |
5c5670fa YG |
88 | RCU_INIT_POINTER(s->psample_group, psample_group); |
89 | ||
90 | if (tb[TCA_SAMPLE_TRUNC_SIZE]) { | |
91 | s->truncate = true; | |
92 | s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); | |
93 | } | |
94 | ||
95 | if (ret == ACT_P_CREATED) | |
96 | tcf_hash_insert(tn, *a); | |
97 | return ret; | |
98 | } | |
99 | ||
100 | static void tcf_sample_cleanup_rcu(struct rcu_head *rcu) | |
101 | { | |
102 | struct tcf_sample *s = container_of(rcu, struct tcf_sample, rcu); | |
103 | struct psample_group *psample_group; | |
104 | ||
105 | psample_group = rcu_dereference_protected(s->psample_group, 1); | |
106 | RCU_INIT_POINTER(s->psample_group, NULL); | |
107 | psample_group_put(psample_group); | |
108 | } | |
109 | ||
110 | static void tcf_sample_cleanup(struct tc_action *a, int bind) | |
111 | { | |
112 | struct tcf_sample *s = to_sample(a); | |
113 | ||
114 | call_rcu(&s->rcu, tcf_sample_cleanup_rcu); | |
115 | } | |
116 | ||
117 | static bool tcf_sample_dev_ok_push(struct net_device *dev) | |
118 | { | |
119 | switch (dev->type) { | |
120 | case ARPHRD_TUNNEL: | |
121 | case ARPHRD_TUNNEL6: | |
122 | case ARPHRD_SIT: | |
123 | case ARPHRD_IPGRE: | |
124 | case ARPHRD_VOID: | |
125 | case ARPHRD_NONE: | |
126 | return false; | |
127 | default: | |
128 | return true; | |
129 | } | |
130 | } | |
131 | ||
132 | static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, | |
133 | struct tcf_result *res) | |
134 | { | |
135 | struct tcf_sample *s = to_sample(a); | |
136 | struct psample_group *psample_group; | |
137 | int retval; | |
138 | int size; | |
139 | int iif; | |
140 | int oif; | |
141 | ||
142 | tcf_lastuse_update(&s->tcf_tm); | |
143 | bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); | |
144 | retval = READ_ONCE(s->tcf_action); | |
145 | ||
146 | rcu_read_lock(); | |
147 | psample_group = rcu_dereference(s->psample_group); | |
148 | ||
149 | /* randomly sample packets according to rate */ | |
150 | if (psample_group && (prandom_u32() % s->rate == 0)) { | |
151 | if (!skb_at_tc_ingress(skb)) { | |
152 | iif = skb->skb_iif; | |
153 | oif = skb->dev->ifindex; | |
154 | } else { | |
155 | iif = skb->dev->ifindex; | |
156 | oif = 0; | |
157 | } | |
158 | ||
159 | /* on ingress, the mac header gets popped, so push it back */ | |
160 | if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) | |
161 | skb_push(skb, skb->mac_len); | |
162 | ||
163 | size = s->truncate ? s->trunc_size : skb->len; | |
164 | psample_sample_packet(psample_group, skb, size, iif, oif, | |
165 | s->rate); | |
166 | ||
167 | if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) | |
168 | skb_pull(skb, skb->mac_len); | |
169 | } | |
170 | ||
171 | rcu_read_unlock(); | |
172 | return retval; | |
173 | } | |
174 | ||
175 | static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, | |
176 | int bind, int ref) | |
177 | { | |
178 | unsigned char *b = skb_tail_pointer(skb); | |
179 | struct tcf_sample *s = to_sample(a); | |
180 | struct tc_sample opt = { | |
181 | .index = s->tcf_index, | |
182 | .action = s->tcf_action, | |
183 | .refcnt = s->tcf_refcnt - ref, | |
184 | .bindcnt = s->tcf_bindcnt - bind, | |
185 | }; | |
186 | struct tcf_t t; | |
187 | ||
188 | if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) | |
189 | goto nla_put_failure; | |
190 | ||
191 | tcf_tm_dump(&t, &s->tcf_tm); | |
192 | if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) | |
193 | goto nla_put_failure; | |
194 | ||
195 | if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) | |
196 | goto nla_put_failure; | |
197 | ||
198 | if (s->truncate) | |
199 | if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) | |
200 | goto nla_put_failure; | |
201 | ||
202 | if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) | |
203 | goto nla_put_failure; | |
204 | return skb->len; | |
205 | ||
206 | nla_put_failure: | |
207 | nlmsg_trim(skb, b); | |
208 | return -1; | |
209 | } | |
210 | ||
211 | static int tcf_sample_walker(struct net *net, struct sk_buff *skb, | |
212 | struct netlink_callback *cb, int type, | |
213 | const struct tc_action_ops *ops) | |
214 | { | |
215 | struct tc_action_net *tn = net_generic(net, sample_net_id); | |
216 | ||
217 | return tcf_generic_walker(tn, skb, cb, type, ops); | |
218 | } | |
219 | ||
220 | static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index) | |
221 | { | |
222 | struct tc_action_net *tn = net_generic(net, sample_net_id); | |
223 | ||
224 | return tcf_hash_search(tn, a, index); | |
225 | } | |
226 | ||
227 | static struct tc_action_ops act_sample_ops = { | |
228 | .kind = "sample", | |
229 | .type = TCA_ACT_SAMPLE, | |
230 | .owner = THIS_MODULE, | |
231 | .act = tcf_sample_act, | |
232 | .dump = tcf_sample_dump, | |
233 | .init = tcf_sample_init, | |
234 | .cleanup = tcf_sample_cleanup, | |
235 | .walk = tcf_sample_walker, | |
236 | .lookup = tcf_sample_search, | |
237 | .size = sizeof(struct tcf_sample), | |
238 | }; | |
239 | ||
240 | static __net_init int sample_init_net(struct net *net) | |
241 | { | |
242 | struct tc_action_net *tn = net_generic(net, sample_net_id); | |
243 | ||
244 | return tc_action_net_init(tn, &act_sample_ops, SAMPLE_TAB_MASK); | |
245 | } | |
246 | ||
247 | static void __net_exit sample_exit_net(struct net *net) | |
248 | { | |
249 | struct tc_action_net *tn = net_generic(net, sample_net_id); | |
250 | ||
251 | tc_action_net_exit(tn); | |
252 | } | |
253 | ||
254 | static struct pernet_operations sample_net_ops = { | |
255 | .init = sample_init_net, | |
256 | .exit = sample_exit_net, | |
257 | .id = &sample_net_id, | |
258 | .size = sizeof(struct tc_action_net), | |
259 | }; | |
260 | ||
261 | static int __init sample_init_module(void) | |
262 | { | |
263 | return tcf_register_action(&act_sample_ops, &sample_net_ops); | |
264 | } | |
265 | ||
266 | static void __exit sample_cleanup_module(void) | |
267 | { | |
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 | ||
274 | MODULE_AUTHOR("Yotam Gigi <yotamg@mellanox.com>"); | |
275 | MODULE_DESCRIPTION("Packet sampling action"); | |
276 | MODULE_LICENSE("GPL v2"); |