1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * cls_cgroup.h Control Group Classifier
4 *
5 * Authors: Thomas Graf <tgraf@suug.ch>
6 */
7
8#ifndef _NET_CLS_CGROUP_H
9#define _NET_CLS_CGROUP_H
10
11#include <linux/cgroup.h>
12#include <linux/hardirq.h>
13#include <linux/rcupdate.h>
14#include <net/sock.h>
15#include <net/inet_sock.h>
16
17#ifdef CONFIG_CGROUP_NET_CLASSID
18struct cgroup_cls_state {
19 struct cgroup_subsys_state css;
20 u32 classid;
21};
22
23struct cgroup_cls_state *task_cls_state(struct task_struct *p);
24
25static inline u32 task_cls_classid(struct task_struct *p)
26{
27 u32 classid;
28
29 if (in_interrupt())
30 return 0;
31
32 rcu_read_lock();
33 classid = container_of(task_css(p, net_cls_cgrp_id),
34 struct cgroup_cls_state, css)->classid;
35 rcu_read_unlock();
36
37 return classid;
38}
39
40static inline void sock_update_classid(struct sock_cgroup_data *skcd)
41{
42 u32 classid;
43
44 classid = task_cls_classid(current);
45 sock_cgroup_set_classid(skcd, classid);
46}
47
48static inline u32 __task_get_classid(struct task_struct *task)
49{
50 return task_cls_state(p: task)->classid;
51}
52
53static inline u32 task_get_classid(const struct sk_buff *skb)
54{
55 u32 classid = __task_get_classid(current);
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 (softirq_count()) {
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(skcd: &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