include/net/cls_cgroup.h

   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
  18 struct cgroup_cls_state {
  19         struct cgroup_subsys_state css;
  20         u32 classid;
  21 };
  22
  23 struct cgroup_cls_state *task_cls_state(struct task_struct *p);
  24
  25 static 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
  40 static 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
  48 static inline u32 __task_get_classid(struct task_struct *task)
  49 {
  50         return task_cls_state(task)->classid;
  51 }
  52
  53 static 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 */
  79 static inline void sock_update_classid(struct sock_cgroup_data *skcd)
  80 {
  81 }
  82
  83 static 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 */