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[sfrench/cifs-2.6.git] / net / sched / act_sample.c
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 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;
52         ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL);
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
61         exists = tcf_idr_check(tn, parm->index, a, bind);
62         if (exists && bind)
63                 return 0;
64
65         if (!exists) {
66                 ret = tcf_idr_create(tn, parm->index, est, a,
67                                      &act_sample_ops, bind, false);
68                 if (ret)
69                         return ret;
70                 ret = ACT_P_CREATED;
71         } else {
72                 tcf_idr_release(*a, bind);
73                 if (!ovr)
74                         return -EEXIST;
75         }
76         s = to_sample(*a);
77
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);
82         if (!psample_group) {
83                 if (ret == ACT_P_CREATED)
84                         tcf_idr_release(*a, bind);
85                 return -ENOMEM;
86         }
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)
95                 tcf_idr_insert(tn, *a);
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
223         return tcf_idr_search(tn, a, index);
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
243         return tc_action_net_init(tn, &act_sample_ops);
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 {
267         rcu_barrier();
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 <yotam.gi@gmail.com>");
275 MODULE_DESCRIPTION("Packet sampling action");
276 MODULE_LICENSE("GPL v2");