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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// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/cls_cgroup.c Control Group Classifier
4 *
5 * Authors: Thomas Graf <tgraf@suug.ch>
6 */
7
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/skbuff.h>
11#include <linux/rcupdate.h>
12#include <net/rtnetlink.h>
13#include <net/pkt_cls.h>
14#include <net/sock.h>
15#include <net/cls_cgroup.h>
16
17struct cls_cgroup_head {
18 u32 handle;
19 struct tcf_exts exts;
20 struct tcf_ematch_tree ematches;
21 struct tcf_proto *tp;
22 struct rcu_work rwork;
23};
24
25static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
26 struct tcf_result *res)
27{
28 struct cls_cgroup_head *head = rcu_dereference_bh(tp->root);
29 u32 classid = task_get_classid(skb);
30
31 if (unlikely(!head))
32 return -1;
33 if (!classid)
34 return -1;
35 if (!tcf_em_tree_match(skb, &head->ematches, NULL))
36 return -1;
37
38 res->classid = classid;
39 res->class = 0;
40
41 return tcf_exts_exec(skb, &head->exts, res);
42}
43
44static void *cls_cgroup_get(struct tcf_proto *tp, u32 handle)
45{
46 return NULL;
47}
48
49static int cls_cgroup_init(struct tcf_proto *tp)
50{
51 return 0;
52}
53
54static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
55 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
56};
57
58static void __cls_cgroup_destroy(struct cls_cgroup_head *head)
59{
60 tcf_exts_destroy(&head->exts);
61 tcf_em_tree_destroy(&head->ematches);
62 tcf_exts_put_net(&head->exts);
63 kfree(head);
64}
65
66static void cls_cgroup_destroy_work(struct work_struct *work)
67{
68 struct cls_cgroup_head *head = container_of(to_rcu_work(work),
69 struct cls_cgroup_head,
70 rwork);
71 rtnl_lock();
72 __cls_cgroup_destroy(head);
73 rtnl_unlock();
74}
75
76static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
77 struct tcf_proto *tp, unsigned long base,
78 u32 handle, struct nlattr **tca,
79 void **arg, bool ovr, bool rtnl_held,
80 struct netlink_ext_ack *extack)
81{
82 struct nlattr *tb[TCA_CGROUP_MAX + 1];
83 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
84 struct cls_cgroup_head *new;
85 int err;
86
87 if (!tca[TCA_OPTIONS])
88 return -EINVAL;
89
90 if (!head && !handle)
91 return -EINVAL;
92
93 if (head && handle != head->handle)
94 return -ENOENT;
95
96 new = kzalloc(sizeof(*head), GFP_KERNEL);
97 if (!new)
98 return -ENOBUFS;
99
100 err = tcf_exts_init(&new->exts, net, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
101 if (err < 0)
102 goto errout;
103 new->handle = handle;
104 new->tp = tp;
105 err = nla_parse_nested_deprecated(tb, TCA_CGROUP_MAX,
106 tca[TCA_OPTIONS], cgroup_policy,
107 NULL);
108 if (err < 0)
109 goto errout;
110
111 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr,
112 true, extack);
113 if (err < 0)
114 goto errout;
115
116 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
117 if (err < 0)
118 goto errout;
119
120 rcu_assign_pointer(tp->root, new);
121 if (head) {
122 tcf_exts_get_net(&head->exts);
123 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
124 }
125 return 0;
126errout:
127 tcf_exts_destroy(&new->exts);
128 kfree(new);
129 return err;
130}
131
132static void cls_cgroup_destroy(struct tcf_proto *tp, bool rtnl_held,
133 struct netlink_ext_ack *extack)
134{
135 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
136
137 /* Head can still be NULL due to cls_cgroup_init(). */
138 if (head) {
139 if (tcf_exts_get_net(&head->exts))
140 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
141 else
142 __cls_cgroup_destroy(head);
143 }
144}
145
146static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last,
147 bool rtnl_held, struct netlink_ext_ack *extack)
148{
149 return -EOPNOTSUPP;
150}
151
152static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg,
153 bool rtnl_held)
154{
155 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
156
157 if (arg->count < arg->skip)
158 goto skip;
159
160 if (!head)
161 return;
162 if (arg->fn(tp, head, arg) < 0) {
163 arg->stop = 1;
164 return;
165 }
166skip:
167 arg->count++;
168}
169
170static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
171 struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
172{
173 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
174 struct nlattr *nest;
175
176 t->tcm_handle = head->handle;
177
178 nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
179 if (nest == NULL)
180 goto nla_put_failure;
181
182 if (tcf_exts_dump(skb, &head->exts) < 0 ||
183 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
184 goto nla_put_failure;
185
186 nla_nest_end(skb, nest);
187
188 if (tcf_exts_dump_stats(skb, &head->exts) < 0)
189 goto nla_put_failure;
190
191 return skb->len;
192
193nla_put_failure:
194 nla_nest_cancel(skb, nest);
195 return -1;
196}
197
198static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
199 .kind = "cgroup",
200 .init = cls_cgroup_init,
201 .change = cls_cgroup_change,
202 .classify = cls_cgroup_classify,
203 .destroy = cls_cgroup_destroy,
204 .get = cls_cgroup_get,
205 .delete = cls_cgroup_delete,
206 .walk = cls_cgroup_walk,
207 .dump = cls_cgroup_dump,
208 .owner = THIS_MODULE,
209};
210
211static int __init init_cgroup_cls(void)
212{
213 return register_tcf_proto_ops(&cls_cgroup_ops);
214}
215
216static void __exit exit_cgroup_cls(void)
217{
218 unregister_tcf_proto_ops(&cls_cgroup_ops);
219}
220
221module_init(init_cgroup_cls);
222module_exit(exit_cgroup_cls);
223MODULE_LICENSE("GPL");