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
  32 static struct ctl_table_set *
  33 net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
  34 {
  35         return &namespaces->net_ns->sysctls;
  36 }
  37
  38 static 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. */
  44 static 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
  56 static struct ctl_table_root net_sysctl_root = {
  57         .lookup = net_ctl_header_lookup,
  58         .permissions = net_ctl_permissions,
  59 };
  60
  61 static 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
  70 static struct ctl_table_root net_sysctl_ro_root = {
  71         .permissions = net_ctl_ro_header_perms,
  72 };
  73
  74 static 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
  82 static void __net_exit sysctl_net_exit(struct net *net)
  83 {
  84         WARN_ON(!list_empty(&net->sysctls.list));
  85 }
  86
  87 static struct pernet_operations sysctl_pernet_ops = {
  88         .init = sysctl_net_init,
  89         .exit = sysctl_net_exit,
  90 };
  91
  92 static __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);
 101 out:
 102         return ret;
 103 }
 104 subsys_initcall(sysctl_init);
 105
 106 struct 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 }
 115 EXPORT_SYMBOL_GPL(register_net_sysctl_table);
 116
 117 struct 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 }
 123 EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);
 124
 125 void unregister_net_sysctl_table(struct ctl_table_header *header)
 126 {
 127         unregister_sysctl_table(header);
 128 }
 129 EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);