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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 struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
26 struct cgroup *cgrp);
27static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp);
28static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp);
29
30struct cgroup_subsys net_cls_subsys = {
31 .name = "net_cls",
32 .create = cgrp_create,
33 .destroy = cgrp_destroy,
34 .populate = cgrp_populate,
35#ifdef CONFIG_NET_CLS_CGROUP
36 .subsys_id = net_cls_subsys_id,
37#endif
38 .module = THIS_MODULE,
39};
40
41
42static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp)
43{
44 return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id),
45 struct cgroup_cls_state, css);
46}
47
48static inline struct cgroup_cls_state *task_cls_state(struct task_struct *p)
49{
50 return container_of(task_subsys_state(p, net_cls_subsys_id),
51 struct cgroup_cls_state, css);
52}
53
54static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
55 struct cgroup *cgrp)
56{
57 struct cgroup_cls_state *cs;
58
59 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
60 if (!cs)
61 return ERR_PTR(-ENOMEM);
62
63 if (cgrp->parent)
64 cs->classid = cgrp_cls_state(cgrp->parent)->classid;
65
66 return &cs->css;
67}
68
69static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
70{
71 kfree(cgrp_cls_state(cgrp));
72}
73
74static u64 read_classid(struct cgroup *cgrp, struct cftype *cft)
75{
76 return cgrp_cls_state(cgrp)->classid;
77}
78
79static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
80{
81 cgrp_cls_state(cgrp)->classid = (u32) value;
82 return 0;
83}
84
85static struct cftype ss_files[] = {
86 {
87 .name = "classid",
88 .read_u64 = read_classid,
89 .write_u64 = write_classid,
90 },
91};
92
93static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
94{
95 return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files));
96}
97
98struct cls_cgroup_head {
99 u32 handle;
100 struct tcf_exts exts;
101 struct tcf_ematch_tree ematches;
102};
103
104static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
105 struct tcf_result *res)
106{
107 struct cls_cgroup_head *head = tp->root;
108 u32 classid;
109
110 rcu_read_lock();
111 classid = task_cls_state(current)->classid;
112 rcu_read_unlock();
113
114 /*
115 * Due to the nature of the classifier it is required to ignore all
116 * packets originating from softirq context as accessing `current'
117 * would lead to false results.
118 *
119 * This test assumes that all callers of dev_queue_xmit() explicitely
120 * disable bh. Knowing this, it is possible to detect softirq based
121 * calls by looking at the number of nested bh disable calls because
122 * softirqs always disables bh.
123 */
124 if (in_serving_softirq()) {
125 /* If there is an sk_classid we'll use that. */
126 if (!skb->sk)
127 return -1;
128 classid = skb->sk->sk_classid;
129 }
130
131 if (!classid)
132 return -1;
133
134 if (!tcf_em_tree_match(skb, &head->ematches, NULL))
135 return -1;
136
137 res->classid = classid;
138 res->class = 0;
139 return tcf_exts_exec(skb, &head->exts, res);
140}
141
142static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle)
143{
144 return 0UL;
145}
146
147static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f)
148{
149}
150
151static int cls_cgroup_init(struct tcf_proto *tp)
152{
153 return 0;
154}
155
156static const struct tcf_ext_map cgroup_ext_map = {
157 .action = TCA_CGROUP_ACT,
158 .police = TCA_CGROUP_POLICE,
159};
160
161static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
162 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
163};
164
165static int cls_cgroup_change(struct tcf_proto *tp, unsigned long base,
166 u32 handle, struct nlattr **tca,
167 unsigned long *arg)
168{
169 struct nlattr *tb[TCA_CGROUP_MAX + 1];
170 struct cls_cgroup_head *head = tp->root;
171 struct tcf_ematch_tree t;
172 struct tcf_exts e;
173 int err;
174
175 if (!tca[TCA_OPTIONS])
176 return -EINVAL;
177
178 if (head == NULL) {
179 if (!handle)
180 return -EINVAL;
181
182 head = kzalloc(sizeof(*head), GFP_KERNEL);
183 if (head == NULL)
184 return -ENOBUFS;
185
186 head->handle = handle;
187
188 tcf_tree_lock(tp);
189 tp->root = head;
190 tcf_tree_unlock(tp);
191 }
192
193 if (handle != head->handle)
194 return -ENOENT;
195
196 err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
197 cgroup_policy);
198 if (err < 0)
199 return err;
200
201 err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &cgroup_ext_map);
202 if (err < 0)
203 return err;
204
205 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t);
206 if (err < 0)
207 return err;
208
209 tcf_exts_change(tp, &head->exts, &e);
210 tcf_em_tree_change(tp, &head->ematches, &t);
211
212 return 0;
213}
214
215static void cls_cgroup_destroy(struct tcf_proto *tp)
216{
217 struct cls_cgroup_head *head = tp->root;
218
219 if (head) {
220 tcf_exts_destroy(tp, &head->exts);
221 tcf_em_tree_destroy(tp, &head->ematches);
222 kfree(head);
223 }
224}
225
226static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg)
227{
228 return -EOPNOTSUPP;
229}
230
231static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
232{
233 struct cls_cgroup_head *head = tp->root;
234
235 if (arg->count < arg->skip)
236 goto skip;
237
238 if (arg->fn(tp, (unsigned long) head, arg) < 0) {
239 arg->stop = 1;
240 return;
241 }
242skip:
243 arg->count++;
244}
245
246static int cls_cgroup_dump(struct tcf_proto *tp, unsigned long fh,
247 struct sk_buff *skb, struct tcmsg *t)
248{
249 struct cls_cgroup_head *head = tp->root;
250 unsigned char *b = skb_tail_pointer(skb);
251 struct nlattr *nest;
252
253 t->tcm_handle = head->handle;
254
255 nest = nla_nest_start(skb, TCA_OPTIONS);
256 if (nest == NULL)
257 goto nla_put_failure;
258
259 if (tcf_exts_dump(skb, &head->exts, &cgroup_ext_map) < 0 ||
260 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
261 goto nla_put_failure;
262
263 nla_nest_end(skb, nest);
264
265 if (tcf_exts_dump_stats(skb, &head->exts, &cgroup_ext_map) < 0)
266 goto nla_put_failure;
267
268 return skb->len;
269
270nla_put_failure:
271 nlmsg_trim(skb, b);
272 return -1;
273}
274
275static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
276 .kind = "cgroup",
277 .init = cls_cgroup_init,
278 .change = cls_cgroup_change,
279 .classify = cls_cgroup_classify,
280 .destroy = cls_cgroup_destroy,
281 .get = cls_cgroup_get,
282 .put = cls_cgroup_put,
283 .delete = cls_cgroup_delete,
284 .walk = cls_cgroup_walk,
285 .dump = cls_cgroup_dump,
286 .owner = THIS_MODULE,
287};
288
289static int __init init_cgroup_cls(void)
290{
291 int ret;
292
293 ret = cgroup_load_subsys(&net_cls_subsys);
294 if (ret)
295 goto out;
296
297#ifndef CONFIG_NET_CLS_CGROUP
298 /* We can't use rcu_assign_pointer because this is an int. */
299 smp_wmb();
300 net_cls_subsys_id = net_cls_subsys.subsys_id;
301#endif
302
303 ret = register_tcf_proto_ops(&cls_cgroup_ops);
304 if (ret)
305 cgroup_unload_subsys(&net_cls_subsys);
306
307out:
308 return ret;
309}
310
311static void __exit exit_cgroup_cls(void)
312{
313 unregister_tcf_proto_ops(&cls_cgroup_ops);
314
315#ifndef CONFIG_NET_CLS_CGROUP
316 net_cls_subsys_id = -1;
317 synchronize_rcu();
318#endif
319
320 cgroup_unload_subsys(&net_cls_subsys);
321}
322
323module_init(init_cgroup_cls);
324module_exit(exit_cgroup_cls);
325MODULE_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");