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_init sysctl_net_init(struct net *net)
  63 {
  64         setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
  65         return 0;
  66 }
  67
  68 static void __net_exit sysctl_net_exit(struct net *net)
  69 {
  70         retire_sysctl_set(&net->sysctls);
  71 }
  72
  73 static struct pernet_operations sysctl_pernet_ops = {
  74         .init = sysctl_net_init,
  75         .exit = sysctl_net_exit,
  76 };
  77
  78 static struct ctl_table_header *net_header;
  79 __init int net_sysctl_init(void)
  80 {
  81         static struct ctl_table empty[1];
  82         int ret = -ENOMEM;
  83         /* Avoid limitations in the sysctl implementation by
  84          * registering "/proc/sys/net" as an empty directory not in a
  85          * network namespace.
  86          */
  87         net_header = register_sysctl("net", empty);
  88         if (!net_header)
  89                 goto out;
  90         ret = register_pernet_subsys(&sysctl_pernet_ops);
  91         if (ret)
  92                 goto out;
  93         register_sysctl_root(&net_sysctl_root);
  94 out:
  95         return ret;
  96 }
  97
  98 struct ctl_table_header *register_net_sysctl(struct net *net,
  99         const char *path, struct ctl_table *table)
 100 {
 101         return __register_sysctl_table(&net->sysctls, path, table);
 102 }
 103 EXPORT_SYMBOL_GPL(register_net_sysctl);
 104
 105 void unregister_net_sysctl_table(struct ctl_table_header *header)
 106 {
 107         unregister_sysctl_table(header);
 108 }
 109 EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);