Line data    Source code

       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         833 : static inline void sock_update_classid(struct sock_cgroup_data *skcd)
      80             : {
      81         833 : }
      82             : 
      83           0 : static inline u32 task_get_classid(const struct sk_buff *skb)
      84             : {
      85           0 :         return 0;
      86             : }
      87             : #endif /* CONFIG_CGROUP_NET_CLASSID */
      88             : #endif  /* _NET_CLS_CGROUP_H */