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5a52ae4e32
Today, Kubernetes is still operating on cgroups v1, however, it is possible to retrieve the task's classid based on 'current' out of connect(), sendmsg(), recvmsg() and bind-related hooks for orchestrators which attach to the root cgroup v2 hook in a mixed env like in case of Cilium, for example, in order to then correlate certain pod traffic and use it as part of the key for BPF map lookups. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/555e1c69db7376c0947007b4951c260e1074efc3.1585323121.git.daniel@iogearbox.net
88 lines
2 KiB
C
88 lines
2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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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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#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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#include <net/inet_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_cgroup_data *skcd)
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{
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u32 classid;
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classid = task_cls_classid(current);
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sock_cgroup_set_classid(skcd, classid);
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}
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static inline u32 __task_get_classid(struct task_struct *task)
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{
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return task_cls_state(task)->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_get_classid(current);
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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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struct sock *sk = skb_to_full_sk(skb);
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/* If there is an sock_cgroup_classid we'll use that. */
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if (!sk || !sk_fullsock(sk))
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return 0;
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classid = sock_cgroup_classid(&sk->sk_cgrp_data);
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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_cgroup_data *skcd)
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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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