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/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 __net_init 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 __net_exit sysctl_net_exit(struct net *net)
  83{
  84        WARN_ON(!list_empty(&net->sysctls.list));
  85}
  86
  87static struct pernet_operations sysctl_pernet_ops = {
  88        .init = sysctl_net_init,
  89        .exit = sysctl_net_exit,
  90};
  91
  92static __init int sysctl_init(void)
  93{
  94        int ret;
  95        ret = register_pernet_subsys(&sysctl_pernet_ops);
  96        if (ret)
  97                goto out;
  98        register_sysctl_root(&net_sysctl_root);
  99        setup_sysctl_set(&net_sysctl_ro_root.default_set, NULL, NULL);
 100        register_sysctl_root(&net_sysctl_ro_root);
 101out:
 102        return ret;
 103}
 104subsys_initcall(sysctl_init);
 105
 106struct ctl_table_header *register_net_sysctl_table(struct net *net,
 107        const struct ctl_path *path, struct ctl_table *table)
 108{
 109        struct nsproxy namespaces;
 110        namespaces = *current->nsproxy;
 111        namespaces.net_ns = net;
 112        return __register_sysctl_paths(&net_sysctl_root,
 113                                        &namespaces, path, table);
 114}
 115EXPORT_SYMBOL_GPL(register_net_sysctl_table);
 116
 117struct ctl_table_header *register_net_sysctl_rotable(const
 118                struct ctl_path *path, struct ctl_table *table)
 119{
 120        return __register_sysctl_paths(&net_sysctl_ro_root,
 121                        &init_nsproxy, path, table);
 122}
 123EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);
 124
 125void unregister_net_sysctl_table(struct ctl_table_header *header)
 126{
 127        unregister_sysctl_table(header);
 128}
 129EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);
 130