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b87a173e25
Split out retrieving the cgroups net_cls classid retrieval into its own function, so that it can be reused later on from other parts of the traffic control subsystem. If there's no skb->sk, then the small helper returns 0 as well, which in cls_cgroup terms means 'could not classify'. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
87 lines
2.0 KiB
C
87 lines
2.0 KiB
C
/*
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* cls_cgroup.h Control Group Classifier
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*
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* Authors: Thomas Graf <tgraf@suug.ch>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#ifndef _NET_CLS_CGROUP_H
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#define _NET_CLS_CGROUP_H
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#include <linux/cgroup.h>
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#include <linux/hardirq.h>
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#include <linux/rcupdate.h>
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#include <net/sock.h>
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#ifdef CONFIG_CGROUP_NET_CLASSID
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struct cgroup_cls_state {
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struct cgroup_subsys_state css;
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u32 classid;
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};
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struct cgroup_cls_state *task_cls_state(struct task_struct *p);
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static inline u32 task_cls_classid(struct task_struct *p)
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{
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u32 classid;
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if (in_interrupt())
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return 0;
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rcu_read_lock();
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classid = container_of(task_css(p, net_cls_cgrp_id),
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struct cgroup_cls_state, css)->classid;
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rcu_read_unlock();
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return classid;
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}
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static inline void sock_update_classid(struct sock *sk)
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{
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u32 classid;
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classid = task_cls_classid(current);
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if (classid != sk->sk_classid)
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sk->sk_classid = classid;
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}
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static inline u32 task_get_classid(const struct sk_buff *skb)
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{
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u32 classid = task_cls_state(current)->classid;
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/* Due to the nature of the classifier it is required to ignore all
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* packets originating from softirq context as accessing `current'
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* would lead to false results.
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*
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* This test assumes that all callers of dev_queue_xmit() explicitly
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* disable bh. Knowing this, it is possible to detect softirq based
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* calls by looking at the number of nested bh disable calls because
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* softirqs always disables bh.
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*/
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if (in_serving_softirq()) {
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/* If there is an sk_classid we'll use that. */
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if (!skb->sk)
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return 0;
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classid = skb->sk->sk_classid;
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}
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return classid;
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}
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#else /* !CONFIG_CGROUP_NET_CLASSID */
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static inline void sock_update_classid(struct sock *sk)
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{
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}
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static inline u32 task_get_classid(const struct sk_buff *skb)
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{
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return 0;
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}
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#endif /* CONFIG_CGROUP_NET_CLASSID */
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#endif /* _NET_CLS_CGROUP_H */
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