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 21 #ifdef CONFIG_CGROUP_NET_CLASSID 22 struct cgroup_cls_state { 23 struct cgroup_subsys_state css; 24 u32 classid; 25 }; 26 27 struct cgroup_cls_state *task_cls_state(struct task_struct *p); 28 29 static inline u32 task_cls_classid(struct task_struct *p) 30 { 31 u32 classid; 32 33 if (in_interrupt()) 34 return 0; 35 36 rcu_read_lock(); 37 classid = container_of(task_css(p, net_cls_cgrp_id), 38 struct cgroup_cls_state, css)->classid; 39 rcu_read_unlock(); 40 41 return classid; 42 } 43 44 static inline void sock_update_classid(struct sock *sk) 45 { 46 u32 classid; 47 48 classid = task_cls_classid(current); 49 if (classid != sk->sk_classid) 50 sk->sk_classid = 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 /* If there is an sk_classid we'll use that. */ 68 if (!skb->sk) 69 return 0; 70 71 classid = skb->sk->sk_classid; 72 } 73 74 return classid; 75 } 76 #else /* !CONFIG_CGROUP_NET_CLASSID */ 77 static inline void sock_update_classid(struct sock *sk) 78 { 79 } 80 81 static inline u32 task_get_classid(const struct sk_buff *skb) 82 { 83 return 0; 84 } 85 #endif /* CONFIG_CGROUP_NET_CLASSID */ 86 #endif /* _NET_CLS_CGROUP_H */ 87