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
css_cls_state(struct cgroup_subsys_state * css)16 static 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
task_cls_state(struct task_struct * p)21 struct 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 }
26 EXPORT_SYMBOL_GPL(task_cls_state);
27
28 static struct cgroup_subsys_state *
cgrp_css_alloc(struct cgroup_subsys_state * parent_css)29 cgrp_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
cgrp_css_online(struct cgroup_subsys_state * css)40 static 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
cgrp_css_free(struct cgroup_subsys_state * css)51 static void cgrp_css_free(struct cgroup_subsys_state *css)
52 {
53 kfree(css_cls_state(css));
54 }
55
update_classid_sock(const void * v,struct file * file,unsigned n)56 static 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
cgrp_attach(struct cgroup_taskset * tset)70 static 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
read_classid(struct cgroup_subsys_state * css,struct cftype * cft)83 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
84 {
85 return css_cls_state(css)->classid;
86 }
87
write_classid(struct cgroup_subsys_state * css,struct cftype * cft,u64 value)88 static 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
112 static struct cftype ss_files[] = {
113 {
114 .name = "classid",
115 .read_u64 = read_classid,
116 .write_u64 = write_classid,
117 },
118 { } /* terminate */
119 };
120
121 struct 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 };
128
