xref: /openbmc/linux/net/core/netclassid_cgroup.c (revision 52fb57e7)
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 
19 static 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 
24 struct cgroup_cls_state *task_cls_state(struct task_struct *p)
25 {
26 	return css_cls_state(task_css(p, net_cls_cgrp_id));
27 }
28 EXPORT_SYMBOL_GPL(task_cls_state);
29 
30 static struct cgroup_subsys_state *
31 cgrp_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 
42 static 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 
53 static void cgrp_css_free(struct cgroup_subsys_state *css)
54 {
55 	kfree(css_cls_state(css));
56 }
57 
58 static 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 
69 static 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 
83 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
84 {
85 	return css_cls_state(css)->classid;
86 }
87 
88 static 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 
96 static struct cftype ss_files[] = {
97 	{
98 		.name		= "classid",
99 		.read_u64	= read_classid,
100 		.write_u64	= write_classid,
101 	},
102 	{ }	/* terminate */
103 };
104 
105 struct 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 	.legacy_cftypes		= ss_files,
111 };
112