LXR linux/net/sysctl

   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/export.h>
  16#include <linux/sysctl.h>
  17#include <linux/nsproxy.h>
  18
  19#include <net/sock.h>
  20
  21#ifdef CONFIG_INET
  22#include <net/ip.h>
  23#endif
  24
  25#ifdef CONFIG_NET
  26#include <linux/if_ether.h>
  27#endif
  28
  29static struct ctl_table_set *
  30net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
  31{
  32        return &namespaces->net_ns->sysctls;
  33}
  34
  35static int is_seen(struct ctl_table_set *set)
  36{
  37        return &current->nsproxy->net_ns->sysctls == set;
  38}
  39
  40/* Return standard mode bits for table entry. */
  41static int net_ctl_permissions(struct ctl_table_root *root,
  42                               struct nsproxy *nsproxy,
  43                               struct ctl_table *table)
  44{
  45        /* Allow network administrator to have same access as root. */
  46        if (capable(CAP_NET_ADMIN)) {
  47                int mode = (table->mode >> 6) & 7;
  48                return (mode << 6) | (mode << 3) | mode;
  49        }
  50        return table->mode;
  51}
  52
  53static struct ctl_table_root net_sysctl_root = {
  54        .lookup = net_ctl_header_lookup,
  55        .permissions = net_ctl_permissions,
  56};
  57
  58static int __net_init sysctl_net_init(struct net *net)
  59{
  60        setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
  61        return 0;
  62}
  63
  64static void __net_exit sysctl_net_exit(struct net *net)
  65{
  66        retire_sysctl_set(&net->sysctls);
  67}
  68
  69static struct pernet_operations sysctl_pernet_ops = {
  70        .init = sysctl_net_init,
  71        .exit = sysctl_net_exit,
  72};
  73
  74static struct ctl_table_header *net_header;
  75__init int net_sysctl_init(void)
  76{
  77        static struct ctl_table empty[1];
  78        int ret = -ENOMEM;
  79        /* Avoid limitations in the sysctl implementation by
  80         * registering "/proc/sys/net" as an empty directory not in a
  81         * network namespace.
  82         */
  83        net_header = register_sysctl("net", empty);
  84        if (!net_header)
  85                goto out;
  86        ret = register_pernet_subsys(&sysctl_pernet_ops);
  87        if (ret)
  88                goto out;
  89        register_sysctl_root(&net_sysctl_root);
  90out:
  91        return ret;
  92}
  93
  94struct ctl_table_header *register_net_sysctl(struct net *net,
  95        const char *path, struct ctl_table *table)
  96{
  97        return __register_sysctl_table(&net->sysctls, path, table);
  98}
  99EXPORT_SYMBOL_GPL(register_net_sysctl);
 100
 101void unregister_net_sysctl_table(struct ctl_table_header *header)
 102{
 103        unregister_sysctl_table(header);
 104}
 105EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);
 106