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(const struct sk_buff *skb) 49 { 50 u32 classid = task_cls_state(current)->classid; 51 52 /* Due to the nature of the classifier it is required to ignore all 53 * packets originating from softirq context as accessing `current' 54 * would lead to false results. 55 * 56 * This test assumes that all callers of dev_queue_xmit() explicitly 57 * disable bh. Knowing this, it is possible to detect softirq based 58 * calls by looking at the number of nested bh disable calls because 59 * softirqs always disables bh. 60 */ 61 if (in_serving_softirq()) { 62 struct sock *sk = skb_to_full_sk(skb); 63 64 /* If there is an sock_cgroup_classid we'll use that. */ 65 if (!sk || !sk_fullsock(sk)) 66 return 0; 67 68 classid = sock_cgroup_classid(&sk->sk_cgrp_data); 69 } 70 71 return classid; 72 } 73 #else /* !CONFIG_CGROUP_NET_CLASSID */ 74 static inline void sock_update_classid(struct sock_cgroup_data *skcd) 75 { 76 } 77 78 static inline u32 task_get_classid(const struct sk_buff *skb) 79 { 80 return 0; 81 } 82 #endif /* CONFIG_CGROUP_NET_CLASSID */ 83 #endif /* _NET_CLS_CGROUP_H */ 84