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 <linux/sched/task.h>
16
17 #include <net/cls_cgroup.h>
18 #include <net/sock.h>
19
20 static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
21 {
22 return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
23 }
24
25 struct cgroup_cls_state *task_cls_state(struct task_struct *p)
26 {
27 return css_cls_state(task_css_check(p, net_cls_cgrp_id,
28 rcu_read_lock_bh_held()));
29 }
30 EXPORT_SYMBOL_GPL(task_cls_state);
31
32 static struct cgroup_subsys_state *
33 cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
34 {
35 struct cgroup_cls_state *cs;
36
37 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
38 if (!cs)
39 return ERR_PTR(-ENOMEM);
40
41 return &cs->css;
42 }
43
44 static int cgrp_css_online(struct cgroup_subsys_state *css)
45 {
46 struct cgroup_cls_state *cs = css_cls_state(css);
47 struct cgroup_cls_state *parent = css_cls_state(css->parent);
48
49 if (parent)
50 cs->classid = parent->classid;
51
52 return 0;
53 }
54
55 static void cgrp_css_free(struct cgroup_subsys_state *css)
56 {
57 kfree(css_cls_state(css));
58 }
59
60 static int update_classid_sock(const void *v, struct file *file, unsigned n)
61 {
62 int err;
63 struct socket *sock = sock_from_file(file, &err);
64
65 if (sock) {
66 spin_lock(&cgroup_sk_update_lock);
67 sock_cgroup_set_classid(&sock->sk->sk_cgrp_data,
68 (unsigned long)v);
69 spin_unlock(&cgroup_sk_update_lock);
70 }
71 return 0;
72 }
73
74 static void cgrp_attach(struct cgroup_taskset *tset)
75 {
76 struct cgroup_subsys_state *css;
77 struct task_struct *p;
78
79 cgroup_taskset_for_each(p, css, tset) {
80 task_lock(p);
81 iterate_fd(p->files, 0, update_classid_sock,
82 (void *)(unsigned long)css_cls_state(css)->classid);
83 task_unlock(p);
84 }
85 }
86
87 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
88 {
89 return css_cls_state(css)->classid;
90 }
91
92 static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
93 u64 value)
94 {
95 struct cgroup_cls_state *cs = css_cls_state(css);
96 struct css_task_iter it;
97 struct task_struct *p;
98
99 cgroup_sk_alloc_disable();
100
101 cs->classid = (u32)value;
102
103 css_task_iter_start(css, 0, &it);
104 while ((p = css_task_iter_next(&it))) {
105 task_lock(p);
106 iterate_fd(p->files, 0, update_classid_sock,
107 (void *)(unsigned long)cs->classid);
108 task_unlock(p);
109 cond_resched();
110 }
111 css_task_iter_end(&it);
112
113 return 0;
114 }
115
116 static struct cftype ss_files[] = {
117 {
118 .name = "classid",
119 .read_u64 = read_classid,
120 .write_u64 = write_classid,
121 },
122 { } /* terminate */
123 };
124
125 struct cgroup_subsys net_cls_cgrp_subsys = {
126 .css_alloc = cgrp_css_alloc,
127 .css_online = cgrp_css_online,
128 .css_free = cgrp_css_free,
129 .attach = cgrp_attach,
130 .legacy_cftypes = ss_files,
131 };
132
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