xref: /linux/net/core/netclassid_cgroup.c (revision a8fe58cec351c25e09c393bf46117c0c47b5a17c) 
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_check(p, net_cls_cgrp_id,
27 					    rcu_read_lock_bh_held()));
28 }
29 EXPORT_SYMBOL_GPL(task_cls_state);
30 
31 static struct cgroup_subsys_state *
32 cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
33 {
34 	struct cgroup_cls_state *cs;
35 
36 	cs = kzalloc(sizeof(*cs), GFP_KERNEL);
37 	if (!cs)
38 		return ERR_PTR(-ENOMEM);
39 
40 	return &cs->css;
41 }
42 
43 static int cgrp_css_online(struct cgroup_subsys_state *css)
44 {
45 	struct cgroup_cls_state *cs = css_cls_state(css);
46 	struct cgroup_cls_state *parent = css_cls_state(css->parent);
47 
48 	if (parent)
49 		cs->classid = parent->classid;
50 
51 	return 0;
52 }
53 
54 static void cgrp_css_free(struct cgroup_subsys_state *css)
55 {
56 	kfree(css_cls_state(css));
57 }
58 
59 static int update_classid_sock(const void *v, struct file *file, unsigned n)
60 {
61 	int err;
62 	struct socket *sock = sock_from_file(file, &err);
63 
64 	if (sock) {
65 		spin_lock(&cgroup_sk_update_lock);
66 		sock_cgroup_set_classid(&sock->sk->sk_cgrp_data,
67 					(unsigned long)v);
68 		spin_unlock(&cgroup_sk_update_lock);
69 	}
70 	return 0;
71 }
72 
73 static void update_classid(struct cgroup_subsys_state *css, void *v)
74 {
75 	struct css_task_iter it;
76 	struct task_struct *p;
77 
78 	css_task_iter_start(css, &it);
79 	while ((p = css_task_iter_next(&it))) {
80 		task_lock(p);
81 		iterate_fd(p->files, 0, update_classid_sock, v);
82 		task_unlock(p);
83 	}
84 	css_task_iter_end(&it);
85 }
86 
87 static void cgrp_attach(struct cgroup_taskset *tset)
88 {
89 	struct cgroup_subsys_state *css;
90 
91 	cgroup_taskset_first(tset, &css);
92 	update_classid(css,
93 		       (void *)(unsigned long)css_cls_state(css)->classid);
94 }
95 
96 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
97 {
98 	return css_cls_state(css)->classid;
99 }
100 
101 static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
102 			 u64 value)
103 {
104 	struct cgroup_cls_state *cs = css_cls_state(css);
105 
106 	cgroup_sk_alloc_disable();
107 
108 	cs->classid = (u32)value;
109 
110 	update_classid(css, (void *)(unsigned long)cs->classid);
111 	return 0;
112 }
113 
114 static struct cftype ss_files[] = {
115 	{
116 		.name		= "classid",
117 		.read_u64	= read_classid,
118 		.write_u64	= write_classid,
119 	},
120 	{ }	/* terminate */
121 };
122 
123 struct cgroup_subsys net_cls_cgrp_subsys = {
124 	.css_alloc		= cgrp_css_alloc,
125 	.css_online		= cgrp_css_online,
126 	.css_free		= cgrp_css_free,
127 	.attach			= cgrp_attach,
128 	.legacy_cftypes		= ss_files,
129 };
130