net/netfilter/xt_mark.c

   1 /* Kernel module to match NFMARK values. */
   2
   3 /* (C) 1999-2001 Marc Boucher <marc@mbsi.ca>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/skbuff.h>
  12
  13 #include <linux/netfilter/xt_mark.h>
  14 #include <linux/netfilter/x_tables.h>
  15
  16 MODULE_LICENSE("GPL");
  17 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
  18 MODULE_DESCRIPTION("iptables mark matching module");
  19 MODULE_ALIAS("ipt_mark");
  20 MODULE_ALIAS("ip6t_mark");
  21
  22 static int
  23 match(const struct sk_buff *skb,
  24       const struct net_device *in,
  25       const struct net_device *out,
  26       const void *matchinfo,
  27       int offset,
  28       unsigned int protoff,
  29       int *hotdrop)
  30 {
  31         const struct xt_mark_info *info = matchinfo;
  32
  33         return ((skb->nfmark & info->mask) == info->mark) ^ info->invert;
  34 }
  35
  36 static int
  37 checkentry(const char *tablename,
  38            const void *entry,
  39            void *matchinfo,
  40            unsigned int matchsize,
  41            unsigned int hook_mask)
  42 {
  43         struct xt_mark_info *minfo = (struct xt_mark_info *) matchinfo;
  44
  45         if (matchsize != XT_ALIGN(sizeof(struct xt_mark_info)))
  46                 return 0;
  47
  48         if (minfo->mark > 0xffffffff || minfo->mask > 0xffffffff) {
  49                 printk(KERN_WARNING "mark: only supports 32bit mark\n");
  50                 return 0;
  51         }
  52
  53         return 1;
  54 }
  55
  56 static struct xt_match mark_match = {
  57         .name           = "mark",
  58         .match          = &match,
  59         .checkentry     = &checkentry,
  60         .me             = THIS_MODULE,
  61 };
  62
  63 static struct xt_match mark6_match = {
  64         .name           = "mark",
  65         .match          = &match,
  66         .checkentry     = &checkentry,
  67         .me             = THIS_MODULE,
  68 };
  69
  70 static int __init init(void)
  71 {
  72         int ret;
  73         ret = xt_register_match(AF_INET, &mark_match);
  74         if (ret)
  75                 return ret;
  76
  77         ret = xt_register_match(AF_INET6, &mark6_match);
  78         if (ret)
  79                 xt_unregister_match(AF_INET, &mark_match);
  80
  81         return ret;
  82 }
  83
  84 static void __exit fini(void)
  85 {
  86         xt_unregister_match(AF_INET, &mark_match);
  87         xt_unregister_match(AF_INET6, &mark6_match);
  88 }
  89
  90 module_init(init);
  91 module_exit(fini);