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