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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/core/netclassid_cgroup.c Classid Cgroupfs Handling
4 *
5 * Authors: Thomas Graf <tgraf@suug.ch>
6 */
7
8#include <linux/slab.h>
9#include <linux/cgroup.h>
10#include <linux/fdtable.h>
11#include <linux/sched/task.h>
12
13#include <net/cls_cgroup.h>
14#include <net/sock.h>
15
16static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
17{
18 return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
19}
20
21struct cgroup_cls_state *task_cls_state(struct task_struct *p)
22{
23 return css_cls_state(task_css_check(p, net_cls_cgrp_id,
24 rcu_read_lock_bh_held()));
25}
26EXPORT_SYMBOL_GPL(task_cls_state);
27
28static struct cgroup_subsys_state *
29cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
30{
31 struct cgroup_cls_state *cs;
32
33 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
34 if (!cs)
35 return ERR_PTR(-ENOMEM);
36
37 return &cs->css;
38}
39
40static int cgrp_css_online(struct cgroup_subsys_state *css)
41{
42 struct cgroup_cls_state *cs = css_cls_state(css);
43 struct cgroup_cls_state *parent = css_cls_state(css->parent);
44
45 if (parent)
46 cs->classid = parent->classid;
47
48 return 0;
49}
50
51static void cgrp_css_free(struct cgroup_subsys_state *css)
52{
53 kfree(css_cls_state(css));
54}
55
56static int update_classid_sock(const void *v, struct file *file, unsigned n)
57{
58 int err;
59 struct socket *sock = sock_from_file(file, &err);
60
61 if (sock) {
62 spin_lock(&cgroup_sk_update_lock);
63 sock_cgroup_set_classid(&sock->sk->sk_cgrp_data,
64 (unsigned long)v);
65 spin_unlock(&cgroup_sk_update_lock);
66 }
67 return 0;
68}
69
70static void cgrp_attach(struct cgroup_taskset *tset)
71{
72 struct cgroup_subsys_state *css;
73 struct task_struct *p;
74
75 cgroup_taskset_for_each(p, css, tset) {
76 task_lock(p);
77 iterate_fd(p->files, 0, update_classid_sock,
78 (void *)(unsigned long)css_cls_state(css)->classid);
79 task_unlock(p);
80 }
81}
82
83static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
84{
85 return css_cls_state(css)->classid;
86}
87
88static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
89 u64 value)
90{
91 struct cgroup_cls_state *cs = css_cls_state(css);
92 struct css_task_iter it;
93 struct task_struct *p;
94
95 cgroup_sk_alloc_disable();
96
97 cs->classid = (u32)value;
98
99 css_task_iter_start(css, 0, &it);
100 while ((p = css_task_iter_next(&it))) {
101 task_lock(p);
102 iterate_fd(p->files, 0, update_classid_sock,
103 (void *)(unsigned long)cs->classid);
104 task_unlock(p);
105 cond_resched();
106 }
107 css_task_iter_end(&it);
108
109 return 0;
110}
111
112static struct cftype ss_files[] = {
113 {
114 .name = "classid",
115 .read_u64 = read_classid,
116 .write_u64 = write_classid,
117 },
118 { } /* terminate */
119};
120
121struct cgroup_subsys net_cls_cgrp_subsys = {
122 .css_alloc = cgrp_css_alloc,
123 .css_online = cgrp_css_online,
124 .css_free = cgrp_css_free,
125 .attach = cgrp_attach,
126 .legacy_cftypes = ss_files,
127};