net/ipv4/netfilter/ipt_comment.c

   1 /*
   2  * Implements a dummy match to allow attaching comments to rules
   3  *
   4  * 2003-05-13 Brad Fisher (brad@info-link.net)
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/skbuff.h>
   9 #include <linux/netfilter_ipv4/ip_tables.h>
  10 #include <linux/netfilter_ipv4/ipt_comment.h>
  11
  12 MODULE_AUTHOR("Brad Fisher <brad@info-link.net>");
  13 MODULE_DESCRIPTION("iptables comment match module");
  14 MODULE_LICENSE("GPL");
  15
  16 static int
  17 match(const struct sk_buff *skb,
  18       const struct net_device *in,
  19       const struct net_device *out,
  20       const void *matchinfo,
  21       int offset,
  22       int *hotdrop)
  23 {
  24         /* We always match */
  25         return 1;
  26 }
  27
  28 static int
  29 checkentry(const char *tablename,
  30            const struct ipt_ip *ip,
  31            void *matchinfo,
  32            unsigned int matchsize,
  33            unsigned int hook_mask)
  34 {
  35         /* Check the size */
  36         if (matchsize != IPT_ALIGN(sizeof(struct ipt_comment_info)))
  37                 return 0;
  38         return 1;
  39 }
  40
  41 static struct ipt_match comment_match = {
  42         .name           = "comment",
  43         .match          = match,
  44         .checkentry     = checkentry,
  45         .me             = THIS_MODULE
  46 };
  47
  48 static int __init init(void)
  49 {
  50         return ipt_register_match(&comment_match);
  51 }
  52
  53 static void __exit fini(void)
  54 {
  55         ipt_unregister_match(&comment_match);
  56 }
  57
  58 module_init(init);
  59 module_exit(fini);