xref: /openbmc/linux/net/core/netclassid_cgroup.c (revision 2c684d89) 
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 		sock->sk->sk_classid = (u32)(unsigned long)v;
66 
67 	return 0;
68 }
69 
70 static void update_classid(struct cgroup_subsys_state *css, void *v)
71 {
72 	struct css_task_iter it;
73 	struct task_struct *p;
74 
75 	css_task_iter_start(css, &it);
76 	while ((p = css_task_iter_next(&it))) {
77 		task_lock(p);
78 		iterate_fd(p->files, 0, update_classid_sock, v);
79 		task_unlock(p);
80 	}
81 	css_task_iter_end(&it);
82 }
83 
84 static void cgrp_attach(struct cgroup_taskset *tset)
85 {
86 	struct cgroup_subsys_state *css;
87 
88 	cgroup_taskset_first(tset, &css);
89 	update_classid(css,
90 		       (void *)(unsigned long)css_cls_state(css)->classid);
91 }
92 
93 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
94 {
95 	return css_cls_state(css)->classid;
96 }
97 
98 static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
99 			 u64 value)
100 {
101 	struct cgroup_cls_state *cs = css_cls_state(css);
102 
103 	cs->classid = (u32)value;
104 
105 	update_classid(css, (void *)(unsigned long)cs->classid);
106 	return 0;
107 }
108 
109 static struct cftype ss_files[] = {
110 	{
111 		.name		= "classid",
112 		.read_u64	= read_classid,
113 		.write_u64	= write_classid,
114 	},
115 	{ }	/* terminate */
116 };
117 
118 struct cgroup_subsys net_cls_cgrp_subsys = {
119 	.css_alloc		= cgrp_css_alloc,
120 	.css_online		= cgrp_css_online,
121 	.css_free		= cgrp_css_free,
122 	.attach			= cgrp_attach,
123 	.legacy_cftypes		= ss_files,
124 };
125