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/slab.h>
13 #include <linux/cgroup.h>
14 #include <linux/fdtable.h>
15 #include <net/cls_cgroup.h>
16 #include <net/sock.h>
17
18 static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
19 {
20 return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
21 }
22
23 struct cgroup_cls_state *task_cls_state(struct task_struct *p)
24 {
25 return css_cls_state(task_css_check(p, net_cls_cgrp_id,
26 rcu_read_lock_bh_held()));
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_sock(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 spin_lock(&cgroup_sk_update_lock);
65 sock_cgroup_set_classid(&sock->sk->sk_cgrp_data,
66 (unsigned long)v);
67 spin_unlock(&cgroup_sk_update_lock);
68 }
69 return 0;
70 }
71
72 static void update_classid(struct cgroup_subsys_state *css, void *v)
73 {
74 struct css_task_iter it;
75 struct task_struct *p;
76
77 css_task_iter_start(css, &it);
78 while ((p = css_task_iter_next(&it))) {
79 task_lock(p);
80 iterate_fd(p->files, 0, update_classid_sock, v);
81 task_unlock(p);
82 }
83 css_task_iter_end(&it);
84 }
85
86 static void cgrp_attach(struct cgroup_taskset *tset)
87 {
88 struct cgroup_subsys_state *css;
89
90 cgroup_taskset_first(tset, &css);
91 update_classid(css,
92 (void *)(unsigned long)css_cls_state(css)->classid);
93 }
94
95 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
96 {
97 return css_cls_state(css)->classid;
98 }
99
100 static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
101 u64 value)
102 {
103 struct cgroup_cls_state *cs = css_cls_state(css);
104
105 cgroup_sk_alloc_disable();
106
107 cs->classid = (u32)value;
108
109 update_classid(css, (void *)(unsigned long)cs->classid);
110 return 0;
111 }
112
113 static struct cftype ss_files[] = {
114 {
115 .name = "classid",
116 .read_u64 = read_classid,
117 .write_u64 = write_classid,
118 },
119 { } /* terminate */
120 };
121
122 struct cgroup_subsys net_cls_cgrp_subsys = {
123 .css_alloc = cgrp_css_alloc,
124 .css_online = cgrp_css_online,
125 .css_free = cgrp_css_free,
126 .attach = cgrp_attach,
127 .legacy_cftypes = ss_files,
128 };
129
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