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