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1/*
2 * net/sched/cls_cgroup.c Control Group Classifier
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Thomas Graf <tgraf@suug.ch>
10 */
11
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/types.h>
15#include <linux/string.h>
16#include <linux/errno.h>
17#include <linux/skbuff.h>
18#include <linux/cgroup.h>
19#include <linux/rcupdate.h>
20#include <net/rtnetlink.h>
21#include <net/pkt_cls.h>
22#include <net/sock.h>
23#include <net/cls_cgroup.h>
24
25static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp)
26{
27 return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id),
28 struct cgroup_cls_state, css);
29}
30
31static inline struct cgroup_cls_state *task_cls_state(struct task_struct *p)
32{
33 return container_of(task_subsys_state(p, net_cls_subsys_id),
34 struct cgroup_cls_state, css);
35}
36
37static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
38{
39 struct cgroup_cls_state *cs;
40
41 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
42 if (!cs)
43 return ERR_PTR(-ENOMEM);
44
45 if (cgrp->parent)
46 cs->classid = cgrp_cls_state(cgrp->parent)->classid;
47
48 return &cs->css;
49}
50
51static void cgrp_destroy(struct cgroup *cgrp)
52{
53 kfree(cgrp_cls_state(cgrp));
54}
55
56static u64 read_classid(struct cgroup *cgrp, struct cftype *cft)
57{
58 return cgrp_cls_state(cgrp)->classid;
59}
60
61static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
62{
63 cgrp_cls_state(cgrp)->classid = (u32) value;
64 return 0;
65}
66
67static struct cftype ss_files[] = {
68 {
69 .name = "classid",
70 .read_u64 = read_classid,
71 .write_u64 = write_classid,
72 },
73 { } /* terminate */
74};
75
76struct cgroup_subsys net_cls_subsys = {
77 .name = "net_cls",
78 .create = cgrp_create,
79 .destroy = cgrp_destroy,
80#ifdef CONFIG_NET_CLS_CGROUP
81 .subsys_id = net_cls_subsys_id,
82#endif
83 .base_cftypes = ss_files,
84 .module = THIS_MODULE,
85};
86
87struct cls_cgroup_head {
88 u32 handle;
89 struct tcf_exts exts;
90 struct tcf_ematch_tree ematches;
91};
92
93static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
94 struct tcf_result *res)
95{
96 struct cls_cgroup_head *head = tp->root;
97 u32 classid;
98
99 rcu_read_lock();
100 classid = task_cls_state(current)->classid;
101 rcu_read_unlock();
102
103 /*
104 * Due to the nature of the classifier it is required to ignore all
105 * packets originating from softirq context as accessing `current'
106 * would lead to false results.
107 *
108 * This test assumes that all callers of dev_queue_xmit() explicitely
109 * disable bh. Knowing this, it is possible to detect softirq based
110 * calls by looking at the number of nested bh disable calls because
111 * softirqs always disables bh.
112 */
113 if (in_serving_softirq()) {
114 /* If there is an sk_classid we'll use that. */
115 if (!skb->sk)
116 return -1;
117 classid = skb->sk->sk_classid;
118 }
119
120 if (!classid)
121 return -1;
122
123 if (!tcf_em_tree_match(skb, &head->ematches, NULL))
124 return -1;
125
126 res->classid = classid;
127 res->class = 0;
128 return tcf_exts_exec(skb, &head->exts, res);
129}
130
131static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle)
132{
133 return 0UL;
134}
135
136static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f)
137{
138}
139
140static int cls_cgroup_init(struct tcf_proto *tp)
141{
142 return 0;
143}
144
145static const struct tcf_ext_map cgroup_ext_map = {
146 .action = TCA_CGROUP_ACT,
147 .police = TCA_CGROUP_POLICE,
148};
149
150static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
151 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
152};
153
154static int cls_cgroup_change(struct tcf_proto *tp, unsigned long base,
155 u32 handle, struct nlattr **tca,
156 unsigned long *arg)
157{
158 struct nlattr *tb[TCA_CGROUP_MAX + 1];
159 struct cls_cgroup_head *head = tp->root;
160 struct tcf_ematch_tree t;
161 struct tcf_exts e;
162 int err;
163
164 if (!tca[TCA_OPTIONS])
165 return -EINVAL;
166
167 if (head == NULL) {
168 if (!handle)
169 return -EINVAL;
170
171 head = kzalloc(sizeof(*head), GFP_KERNEL);
172 if (head == NULL)
173 return -ENOBUFS;
174
175 head->handle = handle;
176
177 tcf_tree_lock(tp);
178 tp->root = head;
179 tcf_tree_unlock(tp);
180 }
181
182 if (handle != head->handle)
183 return -ENOENT;
184
185 err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
186 cgroup_policy);
187 if (err < 0)
188 return err;
189
190 err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &cgroup_ext_map);
191 if (err < 0)
192 return err;
193
194 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t);
195 if (err < 0)
196 return err;
197
198 tcf_exts_change(tp, &head->exts, &e);
199 tcf_em_tree_change(tp, &head->ematches, &t);
200
201 return 0;
202}
203
204static void cls_cgroup_destroy(struct tcf_proto *tp)
205{
206 struct cls_cgroup_head *head = tp->root;
207
208 if (head) {
209 tcf_exts_destroy(tp, &head->exts);
210 tcf_em_tree_destroy(tp, &head->ematches);
211 kfree(head);
212 }
213}
214
215static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg)
216{
217 return -EOPNOTSUPP;
218}
219
220static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
221{
222 struct cls_cgroup_head *head = tp->root;
223
224 if (arg->count < arg->skip)
225 goto skip;
226
227 if (arg->fn(tp, (unsigned long) head, arg) < 0) {
228 arg->stop = 1;
229 return;
230 }
231skip:
232 arg->count++;
233}
234
235static int cls_cgroup_dump(struct tcf_proto *tp, unsigned long fh,
236 struct sk_buff *skb, struct tcmsg *t)
237{
238 struct cls_cgroup_head *head = tp->root;
239 unsigned char *b = skb_tail_pointer(skb);
240 struct nlattr *nest;
241
242 t->tcm_handle = head->handle;
243
244 nest = nla_nest_start(skb, TCA_OPTIONS);
245 if (nest == NULL)
246 goto nla_put_failure;
247
248 if (tcf_exts_dump(skb, &head->exts, &cgroup_ext_map) < 0 ||
249 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
250 goto nla_put_failure;
251
252 nla_nest_end(skb, nest);
253
254 if (tcf_exts_dump_stats(skb, &head->exts, &cgroup_ext_map) < 0)
255 goto nla_put_failure;
256
257 return skb->len;
258
259nla_put_failure:
260 nlmsg_trim(skb, b);
261 return -1;
262}
263
264static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
265 .kind = "cgroup",
266 .init = cls_cgroup_init,
267 .change = cls_cgroup_change,
268 .classify = cls_cgroup_classify,
269 .destroy = cls_cgroup_destroy,
270 .get = cls_cgroup_get,
271 .put = cls_cgroup_put,
272 .delete = cls_cgroup_delete,
273 .walk = cls_cgroup_walk,
274 .dump = cls_cgroup_dump,
275 .owner = THIS_MODULE,
276};
277
278static int __init init_cgroup_cls(void)
279{
280 int ret;
281
282 ret = cgroup_load_subsys(&net_cls_subsys);
283 if (ret)
284 goto out;
285
286#ifndef CONFIG_NET_CLS_CGROUP
287 /* We can't use rcu_assign_pointer because this is an int. */
288 smp_wmb();
289 net_cls_subsys_id = net_cls_subsys.subsys_id;
290#endif
291
292 ret = register_tcf_proto_ops(&cls_cgroup_ops);
293 if (ret)
294 cgroup_unload_subsys(&net_cls_subsys);
295
296out:
297 return ret;
298}
299
300static void __exit exit_cgroup_cls(void)
301{
302 unregister_tcf_proto_ops(&cls_cgroup_ops);
303
304#ifndef CONFIG_NET_CLS_CGROUP
305 net_cls_subsys_id = -1;
306 synchronize_rcu();
307#endif
308
309 cgroup_unload_subsys(&net_cls_subsys);
310}
311
312module_init(init_cgroup_cls);
313module_exit(exit_cgroup_cls);
314MODULE_LICENSE("GPL");
1/*
2 * net/sched/cls_cgroup.c Control Group Classifier
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Thomas Graf <tgraf@suug.ch>
10 */
11
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/skbuff.h>
15#include <linux/rcupdate.h>
16#include <net/rtnetlink.h>
17#include <net/pkt_cls.h>
18#include <net/sock.h>
19#include <net/cls_cgroup.h>
20
21struct cls_cgroup_head {
22 u32 handle;
23 struct tcf_exts exts;
24 struct tcf_ematch_tree ematches;
25};
26
27static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
28 struct tcf_result *res)
29{
30 struct cls_cgroup_head *head = tp->root;
31 u32 classid;
32
33 rcu_read_lock();
34 classid = task_cls_state(current)->classid;
35 rcu_read_unlock();
36
37 /*
38 * Due to the nature of the classifier it is required to ignore all
39 * packets originating from softirq context as accessing `current'
40 * would lead to false results.
41 *
42 * This test assumes that all callers of dev_queue_xmit() explicitely
43 * disable bh. Knowing this, it is possible to detect softirq based
44 * calls by looking at the number of nested bh disable calls because
45 * softirqs always disables bh.
46 */
47 if (in_serving_softirq()) {
48 /* If there is an sk_classid we'll use that. */
49 if (!skb->sk)
50 return -1;
51 classid = skb->sk->sk_classid;
52 }
53
54 if (!classid)
55 return -1;
56
57 if (!tcf_em_tree_match(skb, &head->ematches, NULL))
58 return -1;
59
60 res->classid = classid;
61 res->class = 0;
62 return tcf_exts_exec(skb, &head->exts, res);
63}
64
65static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle)
66{
67 return 0UL;
68}
69
70static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f)
71{
72}
73
74static int cls_cgroup_init(struct tcf_proto *tp)
75{
76 return 0;
77}
78
79static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
80 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
81};
82
83static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
84 struct tcf_proto *tp, unsigned long base,
85 u32 handle, struct nlattr **tca,
86 unsigned long *arg)
87{
88 struct nlattr *tb[TCA_CGROUP_MAX + 1];
89 struct cls_cgroup_head *head = tp->root;
90 struct tcf_ematch_tree t;
91 struct tcf_exts e;
92 int err;
93
94 if (!tca[TCA_OPTIONS])
95 return -EINVAL;
96
97 if (head == NULL) {
98 if (!handle)
99 return -EINVAL;
100
101 head = kzalloc(sizeof(*head), GFP_KERNEL);
102 if (head == NULL)
103 return -ENOBUFS;
104
105 tcf_exts_init(&head->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
106 head->handle = handle;
107
108 tcf_tree_lock(tp);
109 tp->root = head;
110 tcf_tree_unlock(tp);
111 }
112
113 if (handle != head->handle)
114 return -ENOENT;
115
116 err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
117 cgroup_policy);
118 if (err < 0)
119 return err;
120
121 tcf_exts_init(&e, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
122 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e);
123 if (err < 0)
124 return err;
125
126 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t);
127 if (err < 0)
128 return err;
129
130 tcf_exts_change(tp, &head->exts, &e);
131 tcf_em_tree_change(tp, &head->ematches, &t);
132
133 return 0;
134}
135
136static void cls_cgroup_destroy(struct tcf_proto *tp)
137{
138 struct cls_cgroup_head *head = tp->root;
139
140 if (head) {
141 tcf_exts_destroy(tp, &head->exts);
142 tcf_em_tree_destroy(tp, &head->ematches);
143 kfree(head);
144 }
145}
146
147static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg)
148{
149 return -EOPNOTSUPP;
150}
151
152static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
153{
154 struct cls_cgroup_head *head = tp->root;
155
156 if (arg->count < arg->skip)
157 goto skip;
158
159 if (arg->fn(tp, (unsigned long) head, arg) < 0) {
160 arg->stop = 1;
161 return;
162 }
163skip:
164 arg->count++;
165}
166
167static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
168 struct sk_buff *skb, struct tcmsg *t)
169{
170 struct cls_cgroup_head *head = tp->root;
171 unsigned char *b = skb_tail_pointer(skb);
172 struct nlattr *nest;
173
174 t->tcm_handle = head->handle;
175
176 nest = nla_nest_start(skb, TCA_OPTIONS);
177 if (nest == NULL)
178 goto nla_put_failure;
179
180 if (tcf_exts_dump(skb, &head->exts) < 0 ||
181 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
182 goto nla_put_failure;
183
184 nla_nest_end(skb, nest);
185
186 if (tcf_exts_dump_stats(skb, &head->exts) < 0)
187 goto nla_put_failure;
188
189 return skb->len;
190
191nla_put_failure:
192 nlmsg_trim(skb, b);
193 return -1;
194}
195
196static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
197 .kind = "cgroup",
198 .init = cls_cgroup_init,
199 .change = cls_cgroup_change,
200 .classify = cls_cgroup_classify,
201 .destroy = cls_cgroup_destroy,
202 .get = cls_cgroup_get,
203 .put = cls_cgroup_put,
204 .delete = cls_cgroup_delete,
205 .walk = cls_cgroup_walk,
206 .dump = cls_cgroup_dump,
207 .owner = THIS_MODULE,
208};
209
210static int __init init_cgroup_cls(void)
211{
212 return register_tcf_proto_ops(&cls_cgroup_ops);
213}
214
215static void __exit exit_cgroup_cls(void)
216{
217 unregister_tcf_proto_ops(&cls_cgroup_ops);
218}
219
220module_init(init_cgroup_cls);
221module_exit(exit_cgroup_cls);
222MODULE_LICENSE("GPL");