GNU Linux-libre 4.4-gnu1
[releases.git] / net / core / netclassid_cgroup.c
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 };