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       unsigned int protoff,
  27       int *hotdrop)
  28 {
  29         const struct ipt_tos_info *info = matchinfo;
  30
  31         return (skb->nh.iph->tos == info->tos) ^ info->invert;
  32 }
  33
  34 static int
  35 checkentry(const char *tablename,
  36            const void *ip,
  37            void *matchinfo,
  38            unsigned int matchsize,
  39            unsigned int hook_mask)
  40 {
  41         if (matchsize != IPT_ALIGN(sizeof(struct ipt_tos_info)))
  42                 return 0;
  43
  44         return 1;
  45 }
  46
  47 static struct ipt_match tos_match = {
  48         .name           = "tos",
  49         .match          = &match,
  50         .checkentry     = &checkentry,
  51         .me             = THIS_MODULE,
  52 };
  53
  54 static int __init init(void)
  55 {
  56         return ipt_register_match(&tos_match);
  57 }
  58
  59 static void __exit fini(void)
  60 {
  61         ipt_unregister_match(&tos_match);
  62 }
  63
  64 module_init(init);
  65 module_exit(fini);