1  // SPDX-License-Identifier: GPL-2.0
2  /* Kernel object name space definitions
3   *
4   * Copyright (c) 2002-2003 Patrick Mochel
5   * Copyright (c) 2002-2003 Open Source Development Labs
6   * Copyright (c) 2006-2008 Greg Kroah-Hartman <greg@kroah.com>
7   * Copyright (c) 2006-2008 Novell Inc.
8   *
9   * Split from kobject.h by David Howells (dhowells@redhat.com)
10   *
11   * Please read Documentation/core-api/kobject.rst before using the kobject
12   * interface, ESPECIALLY the parts about reference counts and object
13   * destructors.
14   */
15  
16  #ifndef _LINUX_KOBJECT_NS_H
17  #define _LINUX_KOBJECT_NS_H
18  
19  struct sock;
20  struct kobject;
21  
22  /*
23   * Namespace types which are used to tag kobjects and sysfs entries.
24   * Network namespace will likely be the first.
25   */
26  enum kobj_ns_type {
27  	KOBJ_NS_TYPE_NONE = 0,
28  	KOBJ_NS_TYPE_NET,
29  	KOBJ_NS_TYPES
30  };
31  
32  /*
33   * Callbacks so sysfs can determine namespaces
34   *   @grab_current_ns: return a new reference to calling task's namespace
35   *   @netlink_ns: return namespace to which a sock belongs (right?)
36   *   @initial_ns: return the initial namespace (i.e. init_net_ns)
37   *   @drop_ns: drops a reference to namespace
38   */
39  struct kobj_ns_type_operations {
40  	enum kobj_ns_type type;
41  	bool (*current_may_mount)(void);
42  	void *(*grab_current_ns)(void);
43  	const void *(*netlink_ns)(struct sock *sk);
44  	const void *(*initial_ns)(void);
45  	void (*drop_ns)(void *);
46  };
47  
48  int kobj_ns_type_register(const struct kobj_ns_type_operations *ops);
49  int kobj_ns_type_registered(enum kobj_ns_type type);
50  const struct kobj_ns_type_operations *kobj_child_ns_ops(const struct kobject *parent);
51  const struct kobj_ns_type_operations *kobj_ns_ops(const struct kobject *kobj);
52  
53  bool kobj_ns_current_may_mount(enum kobj_ns_type type);
54  void *kobj_ns_grab_current(enum kobj_ns_type type);
55  const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk);
56  const void *kobj_ns_initial(enum kobj_ns_type type);
57  void kobj_ns_drop(enum kobj_ns_type type, void *ns);
58  
59  #endif /* _LINUX_KOBJECT_NS_H */
60