include/net/cls_cgroup.h

   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
  23 struct cgroup_cls_state {
  24         struct cgroup_subsys_state css;
  25         u32 classid;
  26 };
  27
  28 struct cgroup_cls_state *task_cls_state(struct task_struct *p);
  29
  30 static 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
  45 static 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
  53 static 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 */
  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 */