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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 | |
8e8ba854 | 25 | static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp) |
f4009237 | 26 | { |
8e8ba854 LZ |
27 | return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id), |
28 | struct cgroup_cls_state, css); | |
29 | } | |
30 | ||
31 | static 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); | |
f4009237 TG |
35 | } |
36 | ||
761b3ef5 | 37 | static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp) |
f4009237 TG |
38 | { |
39 | struct cgroup_cls_state *cs; | |
40 | ||
cc7ec456 ED |
41 | cs = kzalloc(sizeof(*cs), GFP_KERNEL); |
42 | if (!cs) | |
f4009237 TG |
43 | return ERR_PTR(-ENOMEM); |
44 | ||
45 | if (cgrp->parent) | |
8e8ba854 | 46 | cs->classid = cgrp_cls_state(cgrp->parent)->classid; |
f4009237 TG |
47 | |
48 | return &cs->css; | |
49 | } | |
50 | ||
761b3ef5 | 51 | static void cgrp_destroy(struct cgroup *cgrp) |
f4009237 | 52 | { |
8e8ba854 | 53 | kfree(cgrp_cls_state(cgrp)); |
f4009237 TG |
54 | } |
55 | ||
56 | static u64 read_classid(struct cgroup *cgrp, struct cftype *cft) | |
57 | { | |
8e8ba854 | 58 | return cgrp_cls_state(cgrp)->classid; |
f4009237 TG |
59 | } |
60 | ||
61 | static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value) | |
62 | { | |
8e8ba854 | 63 | cgrp_cls_state(cgrp)->classid = (u32) value; |
f4009237 TG |
64 | return 0; |
65 | } | |
66 | ||
67 | static struct cftype ss_files[] = { | |
68 | { | |
69 | .name = "classid", | |
70 | .read_u64 = read_classid, | |
71 | .write_u64 = write_classid, | |
72 | }, | |
4baf6e33 | 73 | { } /* terminate */ |
f4009237 TG |
74 | }; |
75 | ||
676f7c8f TH |
76 | struct cgroup_subsys net_cls_subsys = { |
77 | .name = "net_cls", | |
78 | .create = cgrp_create, | |
79 | .destroy = cgrp_destroy, | |
676f7c8f TH |
80 | #ifdef CONFIG_NET_CLS_CGROUP |
81 | .subsys_id = net_cls_subsys_id, | |
82 | #endif | |
4baf6e33 | 83 | .base_cftypes = ss_files, |
676f7c8f TH |
84 | .module = THIS_MODULE, |
85 | }; | |
86 | ||
cc7ec456 | 87 | struct cls_cgroup_head { |
f4009237 TG |
88 | u32 handle; |
89 | struct tcf_exts exts; | |
90 | struct tcf_ematch_tree ematches; | |
91 | }; | |
92 | ||
dc7f9f6e | 93 | static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp, |
f4009237 TG |
94 | struct tcf_result *res) |
95 | { | |
96 | struct cls_cgroup_head *head = tp->root; | |
e65fcfd6 | 97 | u32 classid; |
f4009237 | 98 | |
f8451725 HX |
99 | rcu_read_lock(); |
100 | classid = task_cls_state(current)->classid; | |
101 | rcu_read_unlock(); | |
102 | ||
f4009237 TG |
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 | */ | |
75e1056f | 113 | if (in_serving_softirq()) { |
f8451725 HX |
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 | } | |
f4009237 | 119 | |
e65fcfd6 PM |
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); | |
f4009237 TG |
129 | } |
130 | ||
131 | static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle) | |
132 | { | |
133 | return 0UL; | |
134 | } | |
135 | ||
136 | static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f) | |
137 | { | |
138 | } | |
139 | ||
140 | static int cls_cgroup_init(struct tcf_proto *tp) | |
141 | { | |
142 | return 0; | |
143 | } | |
144 | ||
145 | static const struct tcf_ext_map cgroup_ext_map = { | |
146 | .action = TCA_CGROUP_ACT, | |
147 | .police = TCA_CGROUP_POLICE, | |
148 | }; | |
149 | ||
150 | static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = { | |
151 | [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED }, | |
152 | }; | |
153 | ||
af4c6641 EB |
154 | static int cls_cgroup_change(struct sk_buff *in_skb, |
155 | struct tcf_proto *tp, unsigned long base, | |
f4009237 TG |
156 | u32 handle, struct nlattr **tca, |
157 | unsigned long *arg) | |
158 | { | |
cc7ec456 | 159 | struct nlattr *tb[TCA_CGROUP_MAX + 1]; |
f4009237 TG |
160 | struct cls_cgroup_head *head = tp->root; |
161 | struct tcf_ematch_tree t; | |
162 | struct tcf_exts e; | |
163 | int err; | |
164 | ||
52ea3a56 MU |
165 | if (!tca[TCA_OPTIONS]) |
166 | return -EINVAL; | |
167 | ||
f4009237 TG |
168 | if (head == NULL) { |
169 | if (!handle) | |
170 | return -EINVAL; | |
171 | ||
172 | head = kzalloc(sizeof(*head), GFP_KERNEL); | |
173 | if (head == NULL) | |
174 | return -ENOBUFS; | |
175 | ||
176 | head->handle = handle; | |
177 | ||
178 | tcf_tree_lock(tp); | |
179 | tp->root = head; | |
180 | tcf_tree_unlock(tp); | |
181 | } | |
182 | ||
183 | if (handle != head->handle) | |
184 | return -ENOENT; | |
185 | ||
186 | err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS], | |
187 | cgroup_policy); | |
188 | if (err < 0) | |
189 | return err; | |
190 | ||
191 | err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &cgroup_ext_map); | |
192 | if (err < 0) | |
193 | return err; | |
194 | ||
195 | err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t); | |
196 | if (err < 0) | |
197 | return err; | |
198 | ||
199 | tcf_exts_change(tp, &head->exts, &e); | |
200 | tcf_em_tree_change(tp, &head->ematches, &t); | |
201 | ||
202 | return 0; | |
203 | } | |
204 | ||
205 | static void cls_cgroup_destroy(struct tcf_proto *tp) | |
206 | { | |
47a1a1d4 | 207 | struct cls_cgroup_head *head = tp->root; |
f4009237 TG |
208 | |
209 | if (head) { | |
210 | tcf_exts_destroy(tp, &head->exts); | |
211 | tcf_em_tree_destroy(tp, &head->ematches); | |
212 | kfree(head); | |
213 | } | |
214 | } | |
215 | ||
216 | static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg) | |
217 | { | |
218 | return -EOPNOTSUPP; | |
219 | } | |
220 | ||
221 | static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg) | |
222 | { | |
223 | struct cls_cgroup_head *head = tp->root; | |
224 | ||
225 | if (arg->count < arg->skip) | |
226 | goto skip; | |
227 | ||
228 | if (arg->fn(tp, (unsigned long) head, arg) < 0) { | |
229 | arg->stop = 1; | |
230 | return; | |
231 | } | |
232 | skip: | |
233 | arg->count++; | |
234 | } | |
235 | ||
236 | static int cls_cgroup_dump(struct tcf_proto *tp, unsigned long fh, | |
237 | struct sk_buff *skb, struct tcmsg *t) | |
238 | { | |
239 | struct cls_cgroup_head *head = tp->root; | |
240 | unsigned char *b = skb_tail_pointer(skb); | |
241 | struct nlattr *nest; | |
242 | ||
243 | t->tcm_handle = head->handle; | |
244 | ||
245 | nest = nla_nest_start(skb, TCA_OPTIONS); | |
246 | if (nest == NULL) | |
247 | goto nla_put_failure; | |
248 | ||
249 | if (tcf_exts_dump(skb, &head->exts, &cgroup_ext_map) < 0 || | |
250 | tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) | |
251 | goto nla_put_failure; | |
252 | ||
253 | nla_nest_end(skb, nest); | |
254 | ||
255 | if (tcf_exts_dump_stats(skb, &head->exts, &cgroup_ext_map) < 0) | |
256 | goto nla_put_failure; | |
257 | ||
258 | return skb->len; | |
259 | ||
260 | nla_put_failure: | |
261 | nlmsg_trim(skb, b); | |
262 | return -1; | |
263 | } | |
264 | ||
265 | static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { | |
266 | .kind = "cgroup", | |
267 | .init = cls_cgroup_init, | |
268 | .change = cls_cgroup_change, | |
269 | .classify = cls_cgroup_classify, | |
270 | .destroy = cls_cgroup_destroy, | |
271 | .get = cls_cgroup_get, | |
272 | .put = cls_cgroup_put, | |
273 | .delete = cls_cgroup_delete, | |
274 | .walk = cls_cgroup_walk, | |
275 | .dump = cls_cgroup_dump, | |
276 | .owner = THIS_MODULE, | |
277 | }; | |
278 | ||
279 | static int __init init_cgroup_cls(void) | |
280 | { | |
f8451725 HX |
281 | int ret; |
282 | ||
8e039d84 BB |
283 | ret = cgroup_load_subsys(&net_cls_subsys); |
284 | if (ret) | |
f8451725 HX |
285 | goto out; |
286 | ||
287 | #ifndef CONFIG_NET_CLS_CGROUP | |
288 | /* We can't use rcu_assign_pointer because this is an int. */ | |
289 | smp_wmb(); | |
290 | net_cls_subsys_id = net_cls_subsys.subsys_id; | |
291 | #endif | |
292 | ||
293 | ret = register_tcf_proto_ops(&cls_cgroup_ops); | |
294 | if (ret) | |
295 | cgroup_unload_subsys(&net_cls_subsys); | |
296 | ||
297 | out: | |
8e039d84 | 298 | return ret; |
f4009237 TG |
299 | } |
300 | ||
301 | static void __exit exit_cgroup_cls(void) | |
302 | { | |
303 | unregister_tcf_proto_ops(&cls_cgroup_ops); | |
f8451725 HX |
304 | |
305 | #ifndef CONFIG_NET_CLS_CGROUP | |
306 | net_cls_subsys_id = -1; | |
307 | synchronize_rcu(); | |
308 | #endif | |
309 | ||
8e039d84 | 310 | cgroup_unload_subsys(&net_cls_subsys); |
f4009237 TG |
311 | } |
312 | ||
313 | module_init(init_cgroup_cls); | |
314 | module_exit(exit_cgroup_cls); | |
315 | MODULE_LICENSE("GPL"); |