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#include <net/inet_sock.h>
21
22#ifdef CONFIG_CGROUP_NET_CLASSID
23struct cgroup_cls_state {
24 struct cgroup_subsys_state css;
25 u32 classid;
26};
27
28struct cgroup_cls_state *task_cls_state(struct task_struct *p);
29
30static inline u32 task_cls_classid(struct task_struct *p)
31{
32 u32 classid;
33
34 if (in_interrupt())
35 return 0;
36
37 rcu_read_lock();
38 classid = container_of(task_css(p, net_cls_cgrp_id),
39 struct cgroup_cls_state, css)->classid;
40 rcu_read_unlock();
41
42 return classid;
43}
44
45static inline void sock_update_classid(struct sock_cgroup_data *skcd)
46{
47 u32 classid;
48
49 classid = task_cls_classid(current);
50 sock_cgroup_set_classid(skcd, classid);
51}
52
53static inline u32 task_get_classid(const struct sk_buff *skb)
54{
55 u32 classid = task_cls_state(current)->classid;
56
57 /* Due to the nature of the classifier it is required to ignore all
58 * packets originating from softirq context as accessing `current'
59 * would lead to false results.
60 *
61 * This test assumes that all callers of dev_queue_xmit() explicitly
62 * disable bh. Knowing this, it is possible to detect softirq based
63 * calls by looking at the number of nested bh disable calls because
64 * softirqs always disables bh.
65 */
66 if (in_serving_softirq()) {
67 struct sock *sk = skb_to_full_sk(skb);
68
69 /* If there is an sock_cgroup_classid we'll use that. */
70 if (!sk || !sk_fullsock(sk))
71 return 0;
72
73 classid = sock_cgroup_classid(&sk->sk_cgrp_data);
74 }
75
76 return classid;
77}
78#else /* !CONFIG_CGROUP_NET_CLASSID */
79static inline void sock_update_classid(struct sock_cgroup_data *skcd)
80{
81}
82
83static inline u32 task_get_classid(const struct sk_buff *skb)
84{
85 return 0;
86}
87#endif /* CONFIG_CGROUP_NET_CLASSID */
88#endif /* _NET_CLS_CGROUP_H */
89