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 list_head *
  33 net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
  34 {
  35         return &namespaces->net_ns->sysctl_table_headers;
  36 }
  37
  38 static struct ctl_table_root net_sysctl_root = {
  39         .lookup = net_ctl_header_lookup,
  40 };
  41
  42 static LIST_HEAD(net_sysctl_ro_tables);
  43 static struct list_head *net_ctl_ro_header_lookup(struct ctl_table_root *root,
  44                 struct nsproxy *namespaces)
  45 {
  46         return &net_sysctl_ro_tables;
  47 }
  48
  49 static int net_ctl_ro_header_perms(struct ctl_table_root *root,
  50                 struct nsproxy *namespaces, struct ctl_table *table)
  51 {
  52         if (namespaces->net_ns == &init_net)
  53                 return table->mode;
  54         else
  55                 return table->mode & ~0222;
  56 }
  57
  58 static struct ctl_table_root net_sysctl_ro_root = {
  59         .lookup = net_ctl_ro_header_lookup,
  60         .permissions = net_ctl_ro_header_perms,
  61 };
  62
  63 static int sysctl_net_init(struct net *net)
  64 {
  65         INIT_LIST_HEAD(&net->sysctl_table_headers);
  66         return 0;
  67 }
  68
  69 static void sysctl_net_exit(struct net *net)
  70 {
  71         WARN_ON(!list_empty(&net->sysctl_table_headers));
  72         return;
  73 }
  74
  75 static struct pernet_operations sysctl_pernet_ops = {
  76         .init = sysctl_net_init,
  77         .exit = sysctl_net_exit,
  78 };
  79
  80 static __init int sysctl_init(void)
  81 {
  82         int ret;
  83         ret = register_pernet_subsys(&sysctl_pernet_ops);
  84         if (ret)
  85                 goto out;
  86         register_sysctl_root(&net_sysctl_root);
  87         register_sysctl_root(&net_sysctl_ro_root);
  88 out:
  89         return ret;
  90 }
  91 subsys_initcall(sysctl_init);
  92
  93 struct ctl_table_header *register_net_sysctl_table(struct net *net,
  94         const struct ctl_path *path, struct ctl_table *table)
  95 {
  96         struct nsproxy namespaces;
  97         namespaces = *current->nsproxy;
  98         namespaces.net_ns = net;
  99         return __register_sysctl_paths(&net_sysctl_root,
 100                                         &namespaces, path, table);
 101 }
 102 EXPORT_SYMBOL_GPL(register_net_sysctl_table);
 103
 104 struct ctl_table_header *register_net_sysctl_rotable(const
 105                 struct ctl_path *path, struct ctl_table *table)
 106 {
 107         return __register_sysctl_paths(&net_sysctl_ro_root,
 108                         &init_nsproxy, path, table);
 109 }
 110 EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);
 111
 112 void unregister_net_sysctl_table(struct ctl_table_header *header)
 113 {
 114         unregister_sysctl_table(header);
 115 }
 116 EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);