Root/net/sysctl_net.c

1/* -*- linux-c -*-
2 * sysctl_net.c: sysctl interface to net subsystem.
3 *
4 * Begun April 1, 1996, Mike Shaver.
5 * Added /proc/sys/net directories for each protocol family. [MS]
6 *
7 * Revision 1.2 1996/05/08 20:24:40 shaver
8 * Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
9 * NET_IPV4_IP_FORWARD.
10 *
11 *
12 */
13
14#include <linux/mm.h>
15#include <linux/sysctl.h>
16#include <linux/nsproxy.h>
17
18#include <net/sock.h>
19
20#ifdef CONFIG_INET
21#include <net/ip.h>
22#endif
23
24#ifdef CONFIG_NET
25#include <linux/if_ether.h>
26#endif
27
28#ifdef CONFIG_TR
29#include <linux/if_tr.h>
30#endif
31
32static struct ctl_table_set *
33net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
34{
35    return &namespaces->net_ns->sysctls;
36}
37
38static int is_seen(struct ctl_table_set *set)
39{
40    return &current->nsproxy->net_ns->sysctls == set;
41}
42
43/* Return standard mode bits for table entry. */
44static int net_ctl_permissions(struct ctl_table_root *root,
45                   struct nsproxy *nsproxy,
46                   struct ctl_table *table)
47{
48    /* Allow network administrator to have same access as root. */
49    if (capable(CAP_NET_ADMIN)) {
50        int mode = (table->mode >> 6) & 7;
51        return (mode << 6) | (mode << 3) | mode;
52    }
53    return table->mode;
54}
55
56static struct ctl_table_root net_sysctl_root = {
57    .lookup = net_ctl_header_lookup,
58    .permissions = net_ctl_permissions,
59};
60
61static int net_ctl_ro_header_perms(struct ctl_table_root *root,
62        struct nsproxy *namespaces, struct ctl_table *table)
63{
64    if (net_eq(namespaces->net_ns, &init_net))
65        return table->mode;
66    else
67        return table->mode & ~0222;
68}
69
70static struct ctl_table_root net_sysctl_ro_root = {
71    .permissions = net_ctl_ro_header_perms,
72};
73
74static int sysctl_net_init(struct net *net)
75{
76    setup_sysctl_set(&net->sysctls,
77             &net_sysctl_ro_root.default_set,
78             is_seen);
79    return 0;
80}
81
82static void sysctl_net_exit(struct net *net)
83{
84    WARN_ON(!list_empty(&net->sysctls.list));
85    return;
86}
87
88static struct pernet_operations sysctl_pernet_ops = {
89    .init = sysctl_net_init,
90    .exit = sysctl_net_exit,
91};
92
93static __init int sysctl_init(void)
94{
95    int ret;
96    ret = register_pernet_subsys(&sysctl_pernet_ops);
97    if (ret)
98        goto out;
99    register_sysctl_root(&net_sysctl_root);
100    setup_sysctl_set(&net_sysctl_ro_root.default_set, NULL, NULL);
101    register_sysctl_root(&net_sysctl_ro_root);
102out:
103    return ret;
104}
105subsys_initcall(sysctl_init);
106
107struct ctl_table_header *register_net_sysctl_table(struct net *net,
108    const struct ctl_path *path, struct ctl_table *table)
109{
110    struct nsproxy namespaces;
111    namespaces = *current->nsproxy;
112    namespaces.net_ns = net;
113    return __register_sysctl_paths(&net_sysctl_root,
114                    &namespaces, path, table);
115}
116EXPORT_SYMBOL_GPL(register_net_sysctl_table);
117
118struct ctl_table_header *register_net_sysctl_rotable(const
119        struct ctl_path *path, struct ctl_table *table)
120{
121    return __register_sysctl_paths(&net_sysctl_ro_root,
122            &init_nsproxy, path, table);
123}
124EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);
125
126void unregister_net_sysctl_table(struct ctl_table_header *header)
127{
128    unregister_sysctl_table(header);
129}
130EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);
131

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