netclassid_cgroup.c revision 5c9d535b893f30266ea29fe377cb9b002fcd76aa 
1/*
2 * net/core/netclassid_cgroup.c	Classid Cgroupfs Handling
3 *
4 *		This program is free software; you can redistribute it and/or
5 *		modify it under the terms of the GNU General Public License
6 *		as published by the Free Software Foundation; either version
7 *		2 of the License, or (at your option) any later version.
8 *
9 * Authors:	Thomas Graf <tgraf@suug.ch>
10 */
11
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/cgroup.h>
15#include <linux/fdtable.h>
16#include <net/cls_cgroup.h>
17#include <net/sock.h>
18
19static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
20{
21	return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
22}
23
24struct cgroup_cls_state *task_cls_state(struct task_struct *p)
25{
26	return css_cls_state(task_css(p, net_cls_cgrp_id));
27}
28EXPORT_SYMBOL_GPL(task_cls_state);
29
30static struct cgroup_subsys_state *
31cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
32{
33	struct cgroup_cls_state *cs;
34
35	cs = kzalloc(sizeof(*cs), GFP_KERNEL);
36	if (!cs)
37		return ERR_PTR(-ENOMEM);
38
39	return &cs->css;
40}
41
42static int cgrp_css_online(struct cgroup_subsys_state *css)
43{
44	struct cgroup_cls_state *cs = css_cls_state(css);
45	struct cgroup_cls_state *parent = css_cls_state(css->parent);
46
47	if (parent)
48		cs->classid = parent->classid;
49
50	return 0;
51}
52
53static void cgrp_css_free(struct cgroup_subsys_state *css)
54{
55	kfree(css_cls_state(css));
56}
57
58static int update_classid(const void *v, struct file *file, unsigned n)
59{
60	int err;
61	struct socket *sock = sock_from_file(file, &err);
62
63	if (sock)
64		sock->sk->sk_classid = (u32)(unsigned long)v;
65
66	return 0;
67}
68
69static void cgrp_attach(struct cgroup_subsys_state *css,
70			struct cgroup_taskset *tset)
71{
72	struct cgroup_cls_state *cs = css_cls_state(css);
73	void *v = (void *)(unsigned long)cs->classid;
74	struct task_struct *p;
75
76	cgroup_taskset_for_each(p, tset) {
77		task_lock(p);
78		iterate_fd(p->files, 0, update_classid, v);
79		task_unlock(p);
80	}
81}
82
83static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
84{
85	return css_cls_state(css)->classid;
86}
87
88static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
89			 u64 value)
90{
91	css_cls_state(css)->classid = (u32) value;
92
93	return 0;
94}
95
96static struct cftype ss_files[] = {
97	{
98		.name		= "classid",
99		.read_u64	= read_classid,
100		.write_u64	= write_classid,
101	},
102	{ }	/* terminate */
103};
104
105struct cgroup_subsys net_cls_cgrp_subsys = {
106	.css_alloc		= cgrp_css_alloc,
107	.css_online		= cgrp_css_online,
108	.css_free		= cgrp_css_free,
109	.attach			= cgrp_attach,
110	.base_cftypes		= ss_files,
111};
112