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 struct xt_match *match,
  27       const void *matchinfo,
  28       int offset,
  29       unsigned int protoff,
  30       int *hotdrop)
  31 {
  32         const struct xt_mark_info *info = matchinfo;
  33
  34         return ((skb->nfmark & info->mask) == info->mark) ^ info->invert;
  35 }
  36
  37 static int
  38 checkentry(const char *tablename,
  39            const void *entry,
  40            const struct xt_match *match,
  41            void *matchinfo,
  42            unsigned int matchsize,
  43            unsigned int hook_mask)
  44 {
  45         const struct xt_mark_info *minfo = matchinfo;
  46
  47         if (minfo->mark > 0xffffffff || minfo->mask > 0xffffffff) {
  48                 printk(KERN_WARNING "mark: only supports 32bit mark\n");
  49                 return 0;
  50         }
  51         return 1;
  52 }
  53
  54 static struct xt_match mark_match = {
  55         .name           = "mark",
  56         .match          = match,
  57         .matchsize      = sizeof(struct xt_mark_info),
  58         .checkentry     = checkentry,
  59         .family         = AF_INET,
  60         .me             = THIS_MODULE,
  61 };
  62
  63 static struct xt_match mark6_match = {
  64         .name           = "mark",
  65         .match          = match,
  66         .matchsize      = sizeof(struct xt_mark_info),
  67         .checkentry     = checkentry,
  68         .family         = AF_INET6,
  69         .me             = THIS_MODULE,
  70 };
  71
  72 static int __init xt_mark_init(void)
  73 {
  74         int ret;
  75         ret = xt_register_match(&mark_match);
  76         if (ret)
  77                 return ret;
  78
  79         ret = xt_register_match(&mark6_match);
  80         if (ret)
  81                 xt_unregister_match(&mark_match);
  82
  83         return ret;
  84 }
  85
  86 static void __exit xt_mark_fini(void)
  87 {
  88         xt_unregister_match(&mark_match);
  89         xt_unregister_match(&mark6_match);
  90 }
  91
  92 module_init(xt_mark_init);
  93 module_exit(xt_mark_fini);