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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> | |
19 | #include <net/rtnetlink.h> | |
20 | #include <net/pkt_cls.h> | |
21 | ||
22 | struct cgroup_cls_state | |
23 | { | |
24 | struct cgroup_subsys_state css; | |
25 | u32 classid; | |
26 | }; | |
27 | ||
8e039d84 BB |
28 | static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss, |
29 | struct cgroup *cgrp); | |
30 | static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
31 | static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp); | |
32 | ||
33 | struct cgroup_subsys net_cls_subsys = { | |
34 | .name = "net_cls", | |
35 | .create = cgrp_create, | |
36 | .destroy = cgrp_destroy, | |
37 | .populate = cgrp_populate, | |
38 | #ifdef CONFIG_NET_CLS_CGROUP | |
39 | .subsys_id = net_cls_subsys_id, | |
40 | #else | |
41 | #define net_cls_subsys_id net_cls_subsys.subsys_id | |
42 | #endif | |
43 | .module = THIS_MODULE, | |
44 | }; | |
45 | ||
46 | ||
8e8ba854 | 47 | static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp) |
f4009237 | 48 | { |
8e8ba854 LZ |
49 | return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id), |
50 | struct cgroup_cls_state, css); | |
51 | } | |
52 | ||
53 | static inline struct cgroup_cls_state *task_cls_state(struct task_struct *p) | |
54 | { | |
55 | return container_of(task_subsys_state(p, net_cls_subsys_id), | |
56 | struct cgroup_cls_state, css); | |
f4009237 TG |
57 | } |
58 | ||
59 | static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss, | |
60 | struct cgroup *cgrp) | |
61 | { | |
62 | struct cgroup_cls_state *cs; | |
63 | ||
64 | if (!(cs = kzalloc(sizeof(*cs), GFP_KERNEL))) | |
65 | return ERR_PTR(-ENOMEM); | |
66 | ||
67 | if (cgrp->parent) | |
8e8ba854 | 68 | cs->classid = cgrp_cls_state(cgrp->parent)->classid; |
f4009237 TG |
69 | |
70 | return &cs->css; | |
71 | } | |
72 | ||
73 | static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) | |
74 | { | |
8e8ba854 | 75 | kfree(cgrp_cls_state(cgrp)); |
f4009237 TG |
76 | } |
77 | ||
78 | static u64 read_classid(struct cgroup *cgrp, struct cftype *cft) | |
79 | { | |
8e8ba854 | 80 | return cgrp_cls_state(cgrp)->classid; |
f4009237 TG |
81 | } |
82 | ||
83 | static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value) | |
84 | { | |
8e8ba854 | 85 | cgrp_cls_state(cgrp)->classid = (u32) value; |
f4009237 TG |
86 | return 0; |
87 | } | |
88 | ||
89 | static struct cftype ss_files[] = { | |
90 | { | |
91 | .name = "classid", | |
92 | .read_u64 = read_classid, | |
93 | .write_u64 = write_classid, | |
94 | }, | |
95 | }; | |
96 | ||
97 | static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) | |
98 | { | |
99 | return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files)); | |
100 | } | |
101 | ||
f4009237 TG |
102 | struct cls_cgroup_head |
103 | { | |
104 | u32 handle; | |
105 | struct tcf_exts exts; | |
106 | struct tcf_ematch_tree ematches; | |
107 | }; | |
108 | ||
109 | static int cls_cgroup_classify(struct sk_buff *skb, struct tcf_proto *tp, | |
110 | struct tcf_result *res) | |
111 | { | |
112 | struct cls_cgroup_head *head = tp->root; | |
e65fcfd6 | 113 | u32 classid; |
f4009237 TG |
114 | |
115 | /* | |
116 | * Due to the nature of the classifier it is required to ignore all | |
117 | * packets originating from softirq context as accessing `current' | |
118 | * would lead to false results. | |
119 | * | |
120 | * This test assumes that all callers of dev_queue_xmit() explicitely | |
121 | * disable bh. Knowing this, it is possible to detect softirq based | |
122 | * calls by looking at the number of nested bh disable calls because | |
123 | * softirqs always disables bh. | |
124 | */ | |
125 | if (softirq_count() != SOFTIRQ_OFFSET) | |
126 | return -1; | |
127 | ||
128 | rcu_read_lock(); | |
e65fcfd6 | 129 | classid = task_cls_state(current)->classid; |
f4009237 TG |
130 | rcu_read_unlock(); |
131 | ||
e65fcfd6 PM |
132 | if (!classid) |
133 | return -1; | |
134 | ||
135 | if (!tcf_em_tree_match(skb, &head->ematches, NULL)) | |
136 | return -1; | |
137 | ||
138 | res->classid = classid; | |
139 | res->class = 0; | |
140 | return tcf_exts_exec(skb, &head->exts, res); | |
f4009237 TG |
141 | } |
142 | ||
143 | static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle) | |
144 | { | |
145 | return 0UL; | |
146 | } | |
147 | ||
148 | static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f) | |
149 | { | |
150 | } | |
151 | ||
152 | static int cls_cgroup_init(struct tcf_proto *tp) | |
153 | { | |
154 | return 0; | |
155 | } | |
156 | ||
157 | static const struct tcf_ext_map cgroup_ext_map = { | |
158 | .action = TCA_CGROUP_ACT, | |
159 | .police = TCA_CGROUP_POLICE, | |
160 | }; | |
161 | ||
162 | static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = { | |
163 | [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED }, | |
164 | }; | |
165 | ||
166 | static int cls_cgroup_change(struct tcf_proto *tp, unsigned long base, | |
167 | u32 handle, struct nlattr **tca, | |
168 | unsigned long *arg) | |
169 | { | |
170 | struct nlattr *tb[TCA_CGROUP_MAX+1]; | |
171 | struct cls_cgroup_head *head = tp->root; | |
172 | struct tcf_ematch_tree t; | |
173 | struct tcf_exts e; | |
174 | int err; | |
175 | ||
52ea3a56 MU |
176 | if (!tca[TCA_OPTIONS]) |
177 | return -EINVAL; | |
178 | ||
f4009237 TG |
179 | if (head == NULL) { |
180 | if (!handle) | |
181 | return -EINVAL; | |
182 | ||
183 | head = kzalloc(sizeof(*head), GFP_KERNEL); | |
184 | if (head == NULL) | |
185 | return -ENOBUFS; | |
186 | ||
187 | head->handle = handle; | |
188 | ||
189 | tcf_tree_lock(tp); | |
190 | tp->root = head; | |
191 | tcf_tree_unlock(tp); | |
192 | } | |
193 | ||
194 | if (handle != head->handle) | |
195 | return -ENOENT; | |
196 | ||
197 | err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS], | |
198 | cgroup_policy); | |
199 | if (err < 0) | |
200 | return err; | |
201 | ||
202 | err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &cgroup_ext_map); | |
203 | if (err < 0) | |
204 | return err; | |
205 | ||
206 | err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t); | |
207 | if (err < 0) | |
208 | return err; | |
209 | ||
210 | tcf_exts_change(tp, &head->exts, &e); | |
211 | tcf_em_tree_change(tp, &head->ematches, &t); | |
212 | ||
213 | return 0; | |
214 | } | |
215 | ||
216 | static void cls_cgroup_destroy(struct tcf_proto *tp) | |
217 | { | |
47a1a1d4 | 218 | struct cls_cgroup_head *head = tp->root; |
f4009237 TG |
219 | |
220 | if (head) { | |
221 | tcf_exts_destroy(tp, &head->exts); | |
222 | tcf_em_tree_destroy(tp, &head->ematches); | |
223 | kfree(head); | |
224 | } | |
225 | } | |
226 | ||
227 | static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg) | |
228 | { | |
229 | return -EOPNOTSUPP; | |
230 | } | |
231 | ||
232 | static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg) | |
233 | { | |
234 | struct cls_cgroup_head *head = tp->root; | |
235 | ||
236 | if (arg->count < arg->skip) | |
237 | goto skip; | |
238 | ||
239 | if (arg->fn(tp, (unsigned long) head, arg) < 0) { | |
240 | arg->stop = 1; | |
241 | return; | |
242 | } | |
243 | skip: | |
244 | arg->count++; | |
245 | } | |
246 | ||
247 | static int cls_cgroup_dump(struct tcf_proto *tp, unsigned long fh, | |
248 | struct sk_buff *skb, struct tcmsg *t) | |
249 | { | |
250 | struct cls_cgroup_head *head = tp->root; | |
251 | unsigned char *b = skb_tail_pointer(skb); | |
252 | struct nlattr *nest; | |
253 | ||
254 | t->tcm_handle = head->handle; | |
255 | ||
256 | nest = nla_nest_start(skb, TCA_OPTIONS); | |
257 | if (nest == NULL) | |
258 | goto nla_put_failure; | |
259 | ||
260 | if (tcf_exts_dump(skb, &head->exts, &cgroup_ext_map) < 0 || | |
261 | tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) | |
262 | goto nla_put_failure; | |
263 | ||
264 | nla_nest_end(skb, nest); | |
265 | ||
266 | if (tcf_exts_dump_stats(skb, &head->exts, &cgroup_ext_map) < 0) | |
267 | goto nla_put_failure; | |
268 | ||
269 | return skb->len; | |
270 | ||
271 | nla_put_failure: | |
272 | nlmsg_trim(skb, b); | |
273 | return -1; | |
274 | } | |
275 | ||
276 | static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { | |
277 | .kind = "cgroup", | |
278 | .init = cls_cgroup_init, | |
279 | .change = cls_cgroup_change, | |
280 | .classify = cls_cgroup_classify, | |
281 | .destroy = cls_cgroup_destroy, | |
282 | .get = cls_cgroup_get, | |
283 | .put = cls_cgroup_put, | |
284 | .delete = cls_cgroup_delete, | |
285 | .walk = cls_cgroup_walk, | |
286 | .dump = cls_cgroup_dump, | |
287 | .owner = THIS_MODULE, | |
288 | }; | |
289 | ||
290 | static int __init init_cgroup_cls(void) | |
291 | { | |
8e039d84 BB |
292 | int ret = register_tcf_proto_ops(&cls_cgroup_ops); |
293 | if (ret) | |
294 | return ret; | |
295 | ret = cgroup_load_subsys(&net_cls_subsys); | |
296 | if (ret) | |
297 | unregister_tcf_proto_ops(&cls_cgroup_ops); | |
298 | return ret; | |
f4009237 TG |
299 | } |
300 | ||
301 | static void __exit exit_cgroup_cls(void) | |
302 | { | |
303 | unregister_tcf_proto_ops(&cls_cgroup_ops); | |
8e039d84 | 304 | cgroup_unload_subsys(&net_cls_subsys); |
f4009237 TG |
305 | } |
306 | ||
307 | module_init(init_cgroup_cls); | |
308 | module_exit(exit_cgroup_cls); | |
309 | MODULE_LICENSE("GPL"); |