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/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
  29 #ifdef CONFIG_TR
  30 #include <linux/if_tr.h>
  31 #endif
  32
  33 static struct ctl_table_set *
  34 net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
  35 {
  36         return &namespaces->net_ns->sysctls;
  37 }
  38
  39 static int is_seen(struct ctl_table_set *set)
  40 {
  41         return &current->nsproxy->net_ns->sysctls == set;
  42 }
  43
  44 /* Return standard mode bits for table entry. */
  45 static int net_ctl_permissions(struct ctl_table_root *root,
  46                                struct nsproxy *nsproxy,
  47                                struct ctl_table *table)
  48 {
  49         /* Allow network administrator to have same access as root. */
  50         if (capable(CAP_NET_ADMIN)) {
  51                 int mode = (table->mode >> 6) & 7;
  52                 return (mode << 6) | (mode << 3) | mode;
  53         }
  54         return table->mode;
  55 }
  56
  57 static struct ctl_table_root net_sysctl_root = {
  58         .lookup = net_ctl_header_lookup,
  59         .permissions = net_ctl_permissions,
  60 };
  61
  62 static int net_ctl_ro_header_perms(struct ctl_table_root *root,
  63                 struct nsproxy *namespaces, struct ctl_table *table)
  64 {
  65         if (net_eq(namespaces->net_ns, &init_net))
  66                 return table->mode;
  67         else
  68                 return table->mode & ~0222;
  69 }
  70
  71 static struct ctl_table_root net_sysctl_ro_root = {
  72         .permissions = net_ctl_ro_header_perms,
  73 };
  74
  75 static int __net_init sysctl_net_init(struct net *net)
  76 {
  77         setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
  78         return 0;
  79 }
  80
  81 static void __net_exit sysctl_net_exit(struct net *net)
  82 {
  83         retire_sysctl_set(&net->sysctls);
  84 }
  85
  86 static struct pernet_operations sysctl_pernet_ops = {
  87         .init = sysctl_net_init,
  88         .exit = sysctl_net_exit,
  89 };
  90
  91 static __init int net_sysctl_init(void)
  92 {
  93         int ret;
  94         ret = register_pernet_subsys(&sysctl_pernet_ops);
  95         if (ret)
  96                 goto out;
  97         setup_sysctl_set(&net_sysctl_ro_root.default_set, &net_sysctl_ro_root, NULL);
  98         register_sysctl_root(&net_sysctl_ro_root);
  99         register_sysctl_root(&net_sysctl_root);
 100 out:
 101         return ret;
 102 }
 103 subsys_initcall(net_sysctl_init);
 104
 105 struct ctl_table_header *register_net_sysctl_table(struct net *net,
 106         const struct ctl_path *path, struct ctl_table *table)
 107 {
 108         return __register_sysctl_paths(&net->sysctls, path, table);
 109 }
 110 EXPORT_SYMBOL_GPL(register_net_sysctl_table);
 111
 112 struct ctl_table_header *register_net_sysctl_rotable(const
 113                 struct ctl_path *path, struct ctl_table *table)
 114 {
 115         return __register_sysctl_paths(&net_sysctl_ro_root.default_set,
 116                                         path, table);
 117 }
 118 EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);
 119
 120 void unregister_net_sysctl_table(struct ctl_table_header *header)
 121 {
 122         unregister_sysctl_table(header);
 123 }
 124 EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);