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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 struct tcf_proto *tp;
26 union {
27 struct work_struct work;
28 struct rcu_head rcu;
29 };
30};
31
32static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
33 struct tcf_result *res)
34{
35 struct cls_cgroup_head *head = rcu_dereference_bh(tp->root);
36 u32 classid = task_get_classid(skb);
37
38 if (!classid)
39 return -1;
40 if (!tcf_em_tree_match(skb, &head->ematches, NULL))
41 return -1;
42
43 res->classid = classid;
44 res->class = 0;
45
46 return tcf_exts_exec(skb, &head->exts, res);
47}
48
49static void *cls_cgroup_get(struct tcf_proto *tp, u32 handle)
50{
51 return NULL;
52}
53
54static int cls_cgroup_init(struct tcf_proto *tp)
55{
56 return 0;
57}
58
59static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
60 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
61};
62
63static void __cls_cgroup_destroy(struct cls_cgroup_head *head)
64{
65 tcf_exts_destroy(&head->exts);
66 tcf_em_tree_destroy(&head->ematches);
67 tcf_exts_put_net(&head->exts);
68 kfree(head);
69}
70
71static void cls_cgroup_destroy_work(struct work_struct *work)
72{
73 struct cls_cgroup_head *head = container_of(work,
74 struct cls_cgroup_head,
75 work);
76 rtnl_lock();
77 __cls_cgroup_destroy(head);
78 rtnl_unlock();
79}
80
81static void cls_cgroup_destroy_rcu(struct rcu_head *root)
82{
83 struct cls_cgroup_head *head = container_of(root,
84 struct cls_cgroup_head,
85 rcu);
86
87 INIT_WORK(&head->work, cls_cgroup_destroy_work);
88 tcf_queue_work(&head->work);
89}
90
91static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
92 struct tcf_proto *tp, unsigned long base,
93 u32 handle, struct nlattr **tca,
94 void **arg, bool ovr,
95 struct netlink_ext_ack *extack)
96{
97 struct nlattr *tb[TCA_CGROUP_MAX + 1];
98 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
99 struct cls_cgroup_head *new;
100 int err;
101
102 if (!tca[TCA_OPTIONS])
103 return -EINVAL;
104
105 if (!head && !handle)
106 return -EINVAL;
107
108 if (head && handle != head->handle)
109 return -ENOENT;
110
111 new = kzalloc(sizeof(*head), GFP_KERNEL);
112 if (!new)
113 return -ENOBUFS;
114
115 err = tcf_exts_init(&new->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
116 if (err < 0)
117 goto errout;
118 new->handle = handle;
119 new->tp = tp;
120 err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
121 cgroup_policy, NULL);
122 if (err < 0)
123 goto errout;
124
125 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr,
126 extack);
127 if (err < 0)
128 goto errout;
129
130 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
131 if (err < 0)
132 goto errout;
133
134 rcu_assign_pointer(tp->root, new);
135 if (head) {
136 tcf_exts_get_net(&head->exts);
137 call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
138 }
139 return 0;
140errout:
141 tcf_exts_destroy(&new->exts);
142 kfree(new);
143 return err;
144}
145
146static void cls_cgroup_destroy(struct tcf_proto *tp,
147 struct netlink_ext_ack *extack)
148{
149 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
150
151 /* Head can still be NULL due to cls_cgroup_init(). */
152 if (head) {
153 if (tcf_exts_get_net(&head->exts))
154 call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
155 else
156 __cls_cgroup_destroy(head);
157 }
158}
159
160static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last,
161 struct netlink_ext_ack *extack)
162{
163 return -EOPNOTSUPP;
164}
165
166static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
167{
168 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
169
170 if (arg->count < arg->skip)
171 goto skip;
172
173 if (arg->fn(tp, head, arg) < 0) {
174 arg->stop = 1;
175 return;
176 }
177skip:
178 arg->count++;
179}
180
181static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
182 struct sk_buff *skb, struct tcmsg *t)
183{
184 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
185 struct nlattr *nest;
186
187 t->tcm_handle = head->handle;
188
189 nest = nla_nest_start(skb, TCA_OPTIONS);
190 if (nest == NULL)
191 goto nla_put_failure;
192
193 if (tcf_exts_dump(skb, &head->exts) < 0 ||
194 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
195 goto nla_put_failure;
196
197 nla_nest_end(skb, nest);
198
199 if (tcf_exts_dump_stats(skb, &head->exts) < 0)
200 goto nla_put_failure;
201
202 return skb->len;
203
204nla_put_failure:
205 nla_nest_cancel(skb, nest);
206 return -1;
207}
208
209static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
210 .kind = "cgroup",
211 .init = cls_cgroup_init,
212 .change = cls_cgroup_change,
213 .classify = cls_cgroup_classify,
214 .destroy = cls_cgroup_destroy,
215 .get = cls_cgroup_get,
216 .delete = cls_cgroup_delete,
217 .walk = cls_cgroup_walk,
218 .dump = cls_cgroup_dump,
219 .owner = THIS_MODULE,
220};
221
222static int __init init_cgroup_cls(void)
223{
224 return register_tcf_proto_ops(&cls_cgroup_ops);
225}
226
227static void __exit exit_cgroup_cls(void)
228{
229 unregister_tcf_proto_ops(&cls_cgroup_ops);
230}
231
232module_init(init_cgroup_cls);
233module_exit(exit_cgroup_cls);
234MODULE_LICENSE("GPL");