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 static struct ctl_table_set *
  30 net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
  31 {
  32         return &namespaces->net_ns->sysctls;
  33 }
  34
  35 static int is_seen(struct ctl_table_set *set)
  36 {
  37         return &current->nsproxy->net_ns->sysctls == set;
  38 }
  39
  40 /* Return standard mode bits for table entry. */
  41 static int net_ctl_permissions(struct ctl_table_root *root,
  42                                struct nsproxy *nsproxy,
  43                                struct ctl_table *table)
  44 {
  45         /* Allow network administrator to have same access as root. */
  46         if (capable(CAP_NET_ADMIN)) {
  47                 int mode = (table->mode >> 6) & 7;
  48                 return (mode << 6) | (mode << 3) | mode;
  49         }
  50         return table->mode;
  51 }
  52
  53 static struct ctl_table_root net_sysctl_root = {
  54         .lookup = net_ctl_header_lookup,
  55         .permissions = net_ctl_permissions,
  56 };
  57
  58 static int __net_init sysctl_net_init(struct net *net)
  59 {
  60         setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
  61         return 0;
  62 }
  63
  64 static void __net_exit sysctl_net_exit(struct net *net)
  65 {
  66         retire_sysctl_set(&net->sysctls);
  67 }
  68
  69 static struct pernet_operations sysctl_pernet_ops = {
  70         .init = sysctl_net_init,
  71         .exit = sysctl_net_exit,
  72 };
  73
  74 static struct ctl_table_header *net_header;
  75 __init int net_sysctl_init(void)
  76 {
  77         static struct ctl_table empty[1];
  78         int ret = -ENOMEM;
  79         /* Avoid limitations in the sysctl implementation by
  80          * registering "/proc/sys/net" as an empty directory not in a
  81          * network namespace.
  82          */
  83         net_header = register_sysctl("net", empty);
  84         if (!net_header)
  85                 goto out;
  86         ret = register_pernet_subsys(&sysctl_pernet_ops);
  87         if (ret)
  88                 goto out;
  89         register_sysctl_root(&net_sysctl_root);
  90 out:
  91         return ret;
  92 }
  93
  94 struct ctl_table_header *register_net_sysctl(struct net *net,
  95         const char *path, struct ctl_table *table)
  96 {
  97         return __register_sysctl_table(&net->sysctls, path, table);
  98 }
  99 EXPORT_SYMBOL_GPL(register_net_sysctl);
 100
 101 void unregister_net_sysctl_table(struct ctl_table_header *header)
 102 {
 103         unregister_sysctl_table(header);
 104 }
 105 EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);