net/netfilter/nf_sysctl.c

   1 /* nf_sysctl.c  netfilter sysctl registration/unregistation
   2  *
   3  * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
   4  */
   5 #include <linux/module.h>
   6 #include <linux/sysctl.h>
   7 #include <linux/string.h>
   8 #include <linux/slab.h>
   9
  10 static void
  11 path_free(struct ctl_table *path, struct ctl_table *table)
  12 {
  13         struct ctl_table *t, *next;
  14
  15         for (t = path; t != NULL && t != table; t = next) {
  16                 next = t->child;
  17                 kfree(t);
  18         }
  19 }
  20
  21 static struct ctl_table *
  22 path_dup(struct ctl_table *path, struct ctl_table *table)
  23 {
  24         struct ctl_table *t, *last = NULL, *tmp;
  25
  26         for (t = path; t != NULL; t = t->child) {
  27                 /* twice the size since path elements are terminated by an
  28                  * empty element */
  29                 tmp = kmemdup(t, 2 * sizeof(*t), GFP_KERNEL);
  30                 if (tmp == NULL) {
  31                         if (last != NULL)
  32                                 path_free(path, table);
  33                         return NULL;
  34                 }
  35
  36                 if (last != NULL)
  37                         last->child = tmp;
  38                 else
  39                         path = tmp;
  40                 last = tmp;
  41         }
  42
  43         if (last != NULL)
  44                 last->child = table;
  45         else
  46                 path = table;
  47
  48         return path;
  49 }
  50
  51 struct ctl_table_header *
  52 nf_register_sysctl_table(struct ctl_table *path, struct ctl_table *table)
  53 {
  54         struct ctl_table_header *header;
  55
  56         path = path_dup(path, table);
  57         if (path == NULL)
  58                 return NULL;
  59         header = register_sysctl_table(path, 0);
  60         if (header == NULL)
  61                 path_free(path, table);
  62         return header;
  63 }
  64 EXPORT_SYMBOL_GPL(nf_register_sysctl_table);
  65
  66 void
  67 nf_unregister_sysctl_table(struct ctl_table_header *header,
  68                            struct ctl_table *table)
  69 {
  70         struct ctl_table *path = header->ctl_table;
  71
  72         unregister_sysctl_table(header);
  73         path_free(path, table);
  74 }
  75 EXPORT_SYMBOL_GPL(nf_unregister_sysctl_table);
  76
  77 /* net/netfilter */
  78 static struct ctl_table nf_net_netfilter_table[] = {
  79         {
  80                 .ctl_name       = NET_NETFILTER,
  81                 .procname       = "netfilter",
  82                 .mode           = 0555,
  83         },
  84         {
  85                 .ctl_name       = 0
  86         }
  87 };
  88 struct ctl_table nf_net_netfilter_sysctl_path[] = {
  89         {
  90                 .ctl_name       = CTL_NET,
  91                 .procname       = "net",
  92                 .mode           = 0555,
  93                 .child          = nf_net_netfilter_table,
  94         },
  95         {
  96                 .ctl_name       = 0
  97         }
  98 };
  99 EXPORT_SYMBOL_GPL(nf_net_netfilter_sysctl_path);
 100
 101 /* net/ipv4/netfilter */
 102 static struct ctl_table nf_net_ipv4_netfilter_table[] = {
 103         {
 104                 .ctl_name       = NET_IPV4_NETFILTER,
 105                 .procname       = "netfilter",
 106                 .mode           = 0555,
 107         },
 108         {
 109                 .ctl_name       = 0
 110         }
 111 };
 112 static struct ctl_table nf_net_ipv4_table[] = {
 113         {
 114                 .ctl_name       = NET_IPV4,
 115                 .procname       = "ipv4",
 116                 .mode           = 0555,
 117                 .child          = nf_net_ipv4_netfilter_table,
 118         },
 119         {
 120                 .ctl_name       = 0
 121         }
 122 };
 123 struct ctl_table nf_net_ipv4_netfilter_sysctl_path[] = {
 124         {
 125                 .ctl_name       = CTL_NET,
 126                 .procname       = "net",
 127                 .mode           = 0555,
 128                 .child          = nf_net_ipv4_table,
 129         },
 130         {
 131                 .ctl_name       = 0
 132         }
 133 };
 134 EXPORT_SYMBOL_GPL(nf_net_ipv4_netfilter_sysctl_path);