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(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 (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