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 /* Return standard mode bits for table entry. */
  39 static int net_ctl_permissions(struct ctl_table_root *root,
  40                                struct nsproxy *nsproxy,
  41                                struct ctl_table *table)
  42 {
  43         /* Allow network administrator to have same access as root. */
  44         if (capable(CAP_NET_ADMIN)) {
  45                 int mode = (table->mode >> 6) & 7;
  46                 return (mode << 6) | (mode << 3) | mode;
  47         }
  48         return table->mode;
  49 }
  50
  51 static struct ctl_table_root net_sysctl_root = {
  52         .lookup = net_ctl_header_lookup,
  53         .permissions = net_ctl_permissions,
  54 };
  55
  56 static LIST_HEAD(net_sysctl_ro_tables);
  57 static struct list_head *net_ctl_ro_header_lookup(struct ctl_table_root *root,
  58                 struct nsproxy *namespaces)
  59 {
  60         return &net_sysctl_ro_tables;
  61 }
  62
  63 static int net_ctl_ro_header_perms(struct ctl_table_root *root,
  64                 struct nsproxy *namespaces, struct ctl_table *table)
  65 {
  66         if (namespaces->net_ns == &init_net)
  67                 return table->mode;
  68         else
  69                 return table->mode & ~0222;
  70 }
  71
  72 static struct ctl_table_root net_sysctl_ro_root = {
  73         .lookup = net_ctl_ro_header_lookup,
  74         .permissions = net_ctl_ro_header_perms,
  75 };
  76
  77 static int sysctl_net_init(struct net *net)
  78 {
  79         INIT_LIST_HEAD(&net->sysctl_table_headers);
  80         return 0;
  81 }
  82
  83 static void sysctl_net_exit(struct net *net)
  84 {
  85         WARN_ON(!list_empty(&net->sysctl_table_headers));
  86         return;
  87 }
  88
  89 static struct pernet_operations sysctl_pernet_ops = {
  90         .init = sysctl_net_init,
  91         .exit = sysctl_net_exit,
  92 };
  93
  94 static __init int sysctl_init(void)
  95 {
  96         int ret;
  97         ret = register_pernet_subsys(&sysctl_pernet_ops);
  98         if (ret)
  99                 goto out;
 100         register_sysctl_root(&net_sysctl_root);
 101         register_sysctl_root(&net_sysctl_ro_root);
 102 out:
 103         return ret;
 104 }
 105 subsys_initcall(sysctl_init);
 106
 107 struct 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 }
 116 EXPORT_SYMBOL_GPL(register_net_sysctl_table);
 117
 118 struct 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 }
 124 EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);
 125
 126 void unregister_net_sysctl_table(struct ctl_table_header *header)
 127 {
 128         unregister_sysctl_table(header);
 129 }
 130 EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);