net/netfilter/xt_devgroup.c

   1 /*
   2  * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/netdevice.h>
  12
  13 #include <linux/netfilter/xt_devgroup.h>
  14 #include <linux/netfilter/x_tables.h>
  15
  16 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  17 MODULE_LICENSE("GPL");
  18 MODULE_DESCRIPTION("Xtables: Device group match");
  19 MODULE_ALIAS("ipt_devgroup");
  20 MODULE_ALIAS("ip6t_devgroup");
  21
  22 static bool devgroup_mt(const struct sk_buff *skb, struct xt_action_param *par)
  23 {
  24         const struct xt_devgroup_info *info = par->matchinfo;
  25
  26         if (info->flags & XT_DEVGROUP_MATCH_SRC &&
  27             (((info->src_group ^ xt_in(par)->group) & info->src_mask ? 1 : 0) ^
  28              ((info->flags & XT_DEVGROUP_INVERT_SRC) ? 1 : 0)))
  29                 return false;
  30
  31         if (info->flags & XT_DEVGROUP_MATCH_DST &&
  32             (((info->dst_group ^ xt_out(par)->group) & info->dst_mask ? 1 : 0) ^
  33              ((info->flags & XT_DEVGROUP_INVERT_DST) ? 1 : 0)))
  34                 return false;
  35
  36         return true;
  37 }
  38
  39 static int devgroup_mt_checkentry(const struct xt_mtchk_param *par)
  40 {
  41         const struct xt_devgroup_info *info = par->matchinfo;
  42
  43         if (info->flags & ~(XT_DEVGROUP_MATCH_SRC | XT_DEVGROUP_INVERT_SRC |
  44                             XT_DEVGROUP_MATCH_DST | XT_DEVGROUP_INVERT_DST))
  45                 return -EINVAL;
  46
  47         if (info->flags & XT_DEVGROUP_MATCH_SRC &&
  48             par->hook_mask & ~((1 << NF_INET_PRE_ROUTING) |
  49                                (1 << NF_INET_LOCAL_IN) |
  50                                (1 << NF_INET_FORWARD)))
  51                 return -EINVAL;
  52
  53         if (info->flags & XT_DEVGROUP_MATCH_DST &&
  54             par->hook_mask & ~((1 << NF_INET_FORWARD) |
  55                                (1 << NF_INET_LOCAL_OUT) |
  56                                (1 << NF_INET_POST_ROUTING)))
  57                 return -EINVAL;
  58
  59         return 0;
  60 }
  61
  62 static struct xt_match devgroup_mt_reg __read_mostly = {
  63         .name           = "devgroup",
  64         .match          = devgroup_mt,
  65         .checkentry     = devgroup_mt_checkentry,
  66         .matchsize      = sizeof(struct xt_devgroup_info),
  67         .family         = NFPROTO_UNSPEC,
  68         .me             = THIS_MODULE
  69 };
  70
  71 static int __init devgroup_mt_init(void)
  72 {
  73         return xt_register_match(&devgroup_mt_reg);
  74 }
  75
  76 static void __exit devgroup_mt_exit(void)
  77 {
  78         xt_unregister_match(&devgroup_mt_reg);
  79 }
  80
  81 module_init(devgroup_mt_init);
  82 module_exit(devgroup_mt_exit);