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f4009237 TG |
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> | |
5a0e3ad6 | 13 | #include <linux/slab.h> |
f4009237 TG |
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> | |
f8451725 | 19 | #include <linux/rcupdate.h> |
f4009237 TG |
20 | #include <net/rtnetlink.h> |
21 | #include <net/pkt_cls.h> | |
f8451725 HX |
22 | #include <net/sock.h> |
23 | #include <net/cls_cgroup.h> | |
f4009237 | 24 | |
8e039d84 BB |
25 | static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss, |
26 | struct cgroup *cgrp); | |
27 | static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
28 | static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
29 | ||
30 | struct 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 | #else | |
38 | #define net_cls_subsys_id net_cls_subsys.subsys_id | |
39 | #endif | |
40 | .module = THIS_MODULE, | |
41 | }; | |
42 | ||
43 | ||
8e8ba854 | 44 | static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp) |
f4009237 | 45 | { |
8e8ba854 LZ |
46 | return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id), |
47 | struct cgroup_cls_state, css); | |
48 | } | |
49 | ||
50 | static inline struct cgroup_cls_state *task_cls_state(struct task_struct *p) | |
51 | { | |
52 | return container_of(task_subsys_state(p, net_cls_subsys_id), | |
53 | struct cgroup_cls_state, css); | |
f4009237 TG |
54 | } |
55 | ||
56 | static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss, | |
57 | struct cgroup *cgrp) | |
58 | { | |
59 | struct cgroup_cls_state *cs; | |
60 | ||
61 | if (!(cs = kzalloc(sizeof(*cs), GFP_KERNEL))) | |
62 | return ERR_PTR(-ENOMEM); | |
63 | ||
64 | if (cgrp->parent) | |
8e8ba854 | 65 | cs->classid = cgrp_cls_state(cgrp->parent)->classid; |
f4009237 TG |
66 | |
67 | return &cs->css; | |
68 | } | |
69 | ||
70 | static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) | |
71 | { | |
8e8ba854 | 72 | kfree(cgrp_cls_state(cgrp)); |
f4009237 TG |
73 | } |
74 | ||
75 | static u64 read_classid(struct cgroup *cgrp, struct cftype *cft) | |
76 | { | |
8e8ba854 | 77 | return cgrp_cls_state(cgrp)->classid; |
f4009237 TG |
78 | } |
79 | ||
80 | static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value) | |
81 | { | |
8e8ba854 | 82 | cgrp_cls_state(cgrp)->classid = (u32) value; |
f4009237 TG |
83 | return 0; |
84 | } | |
85 | ||
86 | static struct cftype ss_files[] = { | |
87 | { | |
88 | .name = "classid", | |
89 | .read_u64 = read_classid, | |
90 | .write_u64 = write_classid, | |
91 | }, | |
92 | }; | |
93 | ||
94 | static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) | |
95 | { | |
96 | return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files)); | |
97 | } | |
98 | ||
f4009237 TG |
99 | struct cls_cgroup_head |
100 | { | |
101 | u32 handle; | |
102 | struct tcf_exts exts; | |
103 | struct tcf_ematch_tree ematches; | |
104 | }; | |
105 | ||
106 | static int cls_cgroup_classify(struct sk_buff *skb, struct tcf_proto *tp, | |
107 | struct tcf_result *res) | |
108 | { | |
109 | struct cls_cgroup_head *head = tp->root; | |
e65fcfd6 | 110 | u32 classid; |
f4009237 | 111 | |
f8451725 HX |
112 | rcu_read_lock(); |
113 | classid = task_cls_state(current)->classid; | |
114 | rcu_read_unlock(); | |
115 | ||
f4009237 TG |
116 | /* |
117 | * Due to the nature of the classifier it is required to ignore all | |
118 | * packets originating from softirq context as accessing `current' | |
119 | * would lead to false results. | |
120 | * | |
121 | * This test assumes that all callers of dev_queue_xmit() explicitely | |
122 | * disable bh. Knowing this, it is possible to detect softirq based | |
123 | * calls by looking at the number of nested bh disable calls because | |
124 | * softirqs always disables bh. | |
125 | */ | |
75e1056f | 126 | if (in_serving_softirq()) { |
f8451725 HX |
127 | /* If there is an sk_classid we'll use that. */ |
128 | if (!skb->sk) | |
129 | return -1; | |
130 | classid = skb->sk->sk_classid; | |
131 | } | |
f4009237 | 132 | |
e65fcfd6 PM |
133 | if (!classid) |
134 | return -1; | |
135 | ||
136 | if (!tcf_em_tree_match(skb, &head->ematches, NULL)) | |
137 | return -1; | |
138 | ||
139 | res->classid = classid; | |
140 | res->class = 0; | |
141 | return tcf_exts_exec(skb, &head->exts, res); | |
f4009237 TG |
142 | } |
143 | ||
144 | static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle) | |
145 | { | |
146 | return 0UL; | |
147 | } | |
148 | ||
149 | static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f) | |
150 | { | |
151 | } | |
152 | ||
153 | static int cls_cgroup_init(struct tcf_proto *tp) | |
154 | { | |
155 | return 0; | |
156 | } | |
157 | ||
158 | static const struct tcf_ext_map cgroup_ext_map = { | |
159 | .action = TCA_CGROUP_ACT, | |
160 | .police = TCA_CGROUP_POLICE, | |
161 | }; | |
162 | ||
163 | static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = { | |
164 | [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED }, | |
165 | }; | |
166 | ||
167 | static int cls_cgroup_change(struct tcf_proto *tp, unsigned long base, | |
168 | u32 handle, struct nlattr **tca, | |
169 | unsigned long *arg) | |
170 | { | |
171 | struct nlattr *tb[TCA_CGROUP_MAX+1]; | |
172 | struct cls_cgroup_head *head = tp->root; | |
173 | struct tcf_ematch_tree t; | |
174 | struct tcf_exts e; | |
175 | int err; | |
176 | ||
52ea3a56 MU |
177 | if (!tca[TCA_OPTIONS]) |
178 | return -EINVAL; | |
179 | ||
f4009237 TG |
180 | if (head == NULL) { |
181 | if (!handle) | |
182 | return -EINVAL; | |
183 | ||
184 | head = kzalloc(sizeof(*head), GFP_KERNEL); | |
185 | if (head == NULL) | |
186 | return -ENOBUFS; | |
187 | ||
188 | head->handle = handle; | |
189 | ||
190 | tcf_tree_lock(tp); | |
191 | tp->root = head; | |
192 | tcf_tree_unlock(tp); | |
193 | } | |
194 | ||
195 | if (handle != head->handle) | |
196 | return -ENOENT; | |
197 | ||
198 | err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS], | |
199 | cgroup_policy); | |
200 | if (err < 0) | |
201 | return err; | |
202 | ||
203 | err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &cgroup_ext_map); | |
204 | if (err < 0) | |
205 | return err; | |
206 | ||
207 | err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t); | |
208 | if (err < 0) | |
209 | return err; | |
210 | ||
211 | tcf_exts_change(tp, &head->exts, &e); | |
212 | tcf_em_tree_change(tp, &head->ematches, &t); | |
213 | ||
214 | return 0; | |
215 | } | |
216 | ||
217 | static void cls_cgroup_destroy(struct tcf_proto *tp) | |
218 | { | |
47a1a1d4 | 219 | struct cls_cgroup_head *head = tp->root; |
f4009237 TG |
220 | |
221 | if (head) { | |
222 | tcf_exts_destroy(tp, &head->exts); | |
223 | tcf_em_tree_destroy(tp, &head->ematches); | |
224 | kfree(head); | |
225 | } | |
226 | } | |
227 | ||
228 | static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg) | |
229 | { | |
230 | return -EOPNOTSUPP; | |
231 | } | |
232 | ||
233 | static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg) | |
234 | { | |
235 | struct cls_cgroup_head *head = tp->root; | |
236 | ||
237 | if (arg->count < arg->skip) | |
238 | goto skip; | |
239 | ||
240 | if (arg->fn(tp, (unsigned long) head, arg) < 0) { | |
241 | arg->stop = 1; | |
242 | return; | |
243 | } | |
244 | skip: | |
245 | arg->count++; | |
246 | } | |
247 | ||
248 | static int cls_cgroup_dump(struct tcf_proto *tp, unsigned long fh, | |
249 | struct sk_buff *skb, struct tcmsg *t) | |
250 | { | |
251 | struct cls_cgroup_head *head = tp->root; | |
252 | unsigned char *b = skb_tail_pointer(skb); | |
253 | struct nlattr *nest; | |
254 | ||
255 | t->tcm_handle = head->handle; | |
256 | ||
257 | nest = nla_nest_start(skb, TCA_OPTIONS); | |
258 | if (nest == NULL) | |
259 | goto nla_put_failure; | |
260 | ||
261 | if (tcf_exts_dump(skb, &head->exts, &cgroup_ext_map) < 0 || | |
262 | tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) | |
263 | goto nla_put_failure; | |
264 | ||
265 | nla_nest_end(skb, nest); | |
266 | ||
267 | if (tcf_exts_dump_stats(skb, &head->exts, &cgroup_ext_map) < 0) | |
268 | goto nla_put_failure; | |
269 | ||
270 | return skb->len; | |
271 | ||
272 | nla_put_failure: | |
273 | nlmsg_trim(skb, b); | |
274 | return -1; | |
275 | } | |
276 | ||
277 | static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { | |
278 | .kind = "cgroup", | |
279 | .init = cls_cgroup_init, | |
280 | .change = cls_cgroup_change, | |
281 | .classify = cls_cgroup_classify, | |
282 | .destroy = cls_cgroup_destroy, | |
283 | .get = cls_cgroup_get, | |
284 | .put = cls_cgroup_put, | |
285 | .delete = cls_cgroup_delete, | |
286 | .walk = cls_cgroup_walk, | |
287 | .dump = cls_cgroup_dump, | |
288 | .owner = THIS_MODULE, | |
289 | }; | |
290 | ||
291 | static int __init init_cgroup_cls(void) | |
292 | { | |
f8451725 HX |
293 | int ret; |
294 | ||
8e039d84 BB |
295 | ret = cgroup_load_subsys(&net_cls_subsys); |
296 | if (ret) | |
f8451725 HX |
297 | goto out; |
298 | ||
299 | #ifndef CONFIG_NET_CLS_CGROUP | |
300 | /* We can't use rcu_assign_pointer because this is an int. */ | |
301 | smp_wmb(); | |
302 | net_cls_subsys_id = net_cls_subsys.subsys_id; | |
303 | #endif | |
304 | ||
305 | ret = register_tcf_proto_ops(&cls_cgroup_ops); | |
306 | if (ret) | |
307 | cgroup_unload_subsys(&net_cls_subsys); | |
308 | ||
309 | out: | |
8e039d84 | 310 | return ret; |
f4009237 TG |
311 | } |
312 | ||
313 | static void __exit exit_cgroup_cls(void) | |
314 | { | |
315 | unregister_tcf_proto_ops(&cls_cgroup_ops); | |
f8451725 HX |
316 | |
317 | #ifndef CONFIG_NET_CLS_CGROUP | |
318 | net_cls_subsys_id = -1; | |
319 | synchronize_rcu(); | |
320 | #endif | |
321 | ||
8e039d84 | 322 | cgroup_unload_subsys(&net_cls_subsys); |
f4009237 TG |
323 | } |
324 | ||
325 | module_init(init_cgroup_cls); | |
326 | module_exit(exit_cgroup_cls); | |
327 | MODULE_LICENSE("GPL"); |