net/ipv4/netfilter/ipt_tos.c

   1 /* Kernel module to match TOS values. */
   2
   3 /* (C) 1999-2001 Paul `Rusty' Russell
   4  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/skbuff.h>
  13
  14 #include <linux/netfilter_ipv4/ipt_tos.h>
  15 #include <linux/netfilter_ipv4/ip_tables.h>
  16
  17 MODULE_LICENSE("GPL");
  18 MODULE_DESCRIPTION("iptables TOS match module");
  19
  20 static int
  21 match(const struct sk_buff *skb,
  22       const struct net_device *in,
  23       const struct net_device *out,
  24       const void *matchinfo,
  25       int offset,
  26       int *hotdrop)
  27 {
  28         const struct ipt_tos_info *info = matchinfo;
  29
  30         return (skb->nh.iph->tos == info->tos) ^ info->invert;
  31 }
  32
  33 static int
  34 checkentry(const char *tablename,
  35            const struct ipt_ip *ip,
  36            void *matchinfo,
  37            unsigned int matchsize,
  38            unsigned int hook_mask)
  39 {
  40         if (matchsize != IPT_ALIGN(sizeof(struct ipt_tos_info)))
  41                 return 0;
  42
  43         return 1;
  44 }
  45
  46 static struct ipt_match tos_match = {
  47         .name           = "tos",
  48         .match          = &match,
  49         .checkentry     = &checkentry,
  50         .me             = THIS_MODULE,
  51 };
  52
  53 static int __init init(void)
  54 {
  55         return ipt_register_match(&tos_match);
  56 }
  57
  58 static void __exit fini(void)
  59 {
  60         ipt_unregister_match(&tos_match);
  61 }
  62
  63 module_init(init);
  64 module_exit(fini);