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1/*
2 * cls_cgroup.h Control Group Classifier
3 *
4 * Authors: Thomas Graf <tgraf@suug.ch>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 */
12
13#ifndef _NET_CLS_CGROUP_H
14#define _NET_CLS_CGROUP_H
15
16#include <linux/cgroup.h>
17#include <linux/hardirq.h>
18#include <linux/rcupdate.h>
19#include <net/sock.h>
20
21#ifdef CONFIG_CGROUP_NET_CLASSID
22struct cgroup_cls_state {
23 struct cgroup_subsys_state css;
24 u32 classid;
25};
26
27struct cgroup_cls_state *task_cls_state(struct task_struct *p);
28
29static inline u32 task_cls_classid(struct task_struct *p)
30{
31 u32 classid;
32
33 if (in_interrupt())
34 return 0;
35
36 rcu_read_lock();
37 classid = container_of(task_css(p, net_cls_cgrp_id),
38 struct cgroup_cls_state, css)->classid;
39 rcu_read_unlock();
40
41 return classid;
42}
43
44static inline void sock_update_classid(struct sock_cgroup_data *skcd)
45{
46 u32 classid;
47
48 classid = task_cls_classid(current);
49 sock_cgroup_set_classid(skcd, classid);
50}
51
52static inline u32 task_get_classid(const struct sk_buff *skb)
53{
54 u32 classid = task_cls_state(current)->classid;
55
56 /* Due to the nature of the classifier it is required to ignore all
57 * packets originating from softirq context as accessing `current'
58 * would lead to false results.
59 *
60 * This test assumes that all callers of dev_queue_xmit() explicitly
61 * disable bh. Knowing this, it is possible to detect softirq based
62 * calls by looking at the number of nested bh disable calls because
63 * softirqs always disables bh.
64 */
65 if (in_serving_softirq()) {
66 /* If there is an sock_cgroup_classid we'll use that. */
67 if (!skb->sk)
68 return 0;
69
70 classid = sock_cgroup_classid(&skb->sk->sk_cgrp_data);
71 }
72
73 return classid;
74}
75#else /* !CONFIG_CGROUP_NET_CLASSID */
76static inline void sock_update_classid(struct sock_cgroup_data *skcd)
77{
78}
79
80static inline u32 task_get_classid(const struct sk_buff *skb)
81{
82 return 0;
83}
84#endif /* CONFIG_CGROUP_NET_CLASSID */
85#endif /* _NET_CLS_CGROUP_H */