net/ipv6/netfilter/ip6t_eui64.c

   1 /* Kernel module to match EUI64 address parameters. */
   2
   3 /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
   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 #include <linux/ipv6.h>
  13 #include <linux/if_ether.h>
  14
  15 #include <linux/netfilter_ipv6/ip6_tables.h>
  16
  17 MODULE_DESCRIPTION("IPv6 EUI64 address checking match");
  18 MODULE_LICENSE("GPL");
  19 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
  20
  21 static int
  22 match(const struct sk_buff *skb,
  23       const struct net_device *in,
  24       const struct net_device *out,
  25       const void *matchinfo,
  26       int offset,
  27       unsigned int protoff,
  28       int *hotdrop)
  29 {
  30
  31     unsigned char eui64[8];
  32     int i=0;
  33
  34      if ( !(skb->mac.raw >= skb->head
  35                 && (skb->mac.raw + ETH_HLEN) <= skb->data)
  36                 && offset != 0) {
  37                         *hotdrop = 1;
  38                         return 0;
  39                 }
  40
  41     memset(eui64, 0, sizeof(eui64));
  42
  43     if (eth_hdr(skb)->h_proto == ntohs(ETH_P_IPV6)) {
  44       if (skb->nh.ipv6h->version == 0x6) {
  45          memcpy(eui64, eth_hdr(skb)->h_source, 3);
  46          memcpy(eui64 + 5, eth_hdr(skb)->h_source + 3, 3);
  47          eui64[3]=0xff;
  48          eui64[4]=0xfe;
  49          eui64[0] |= 0x02;
  50
  51          i=0;
  52          while ((skb->nh.ipv6h->saddr.s6_addr[8+i] ==
  53                          eui64[i]) && (i<8)) i++;
  54
  55          if ( i == 8 )
  56                 return 1;
  57       }
  58     }
  59
  60     return 0;
  61 }
  62
  63 static int
  64 ip6t_eui64_checkentry(const char *tablename,
  65                    const struct ip6t_ip6 *ip,
  66                    void *matchinfo,
  67                    unsigned int matchsize,
  68                    unsigned int hook_mask)
  69 {
  70         if (hook_mask
  71             & ~((1 << NF_IP6_PRE_ROUTING) | (1 << NF_IP6_LOCAL_IN) |
  72                 (1 << NF_IP6_FORWARD))) {
  73                 printk("ip6t_eui64: only valid for PRE_ROUTING, LOCAL_IN or FORWARD.\n");
  74                 return 0;
  75         }
  76
  77         if (matchsize != IP6T_ALIGN(sizeof(int)))
  78                 return 0;
  79
  80         return 1;
  81 }
  82
  83 static struct ip6t_match eui64_match = {
  84         .name           = "eui64",
  85         .match          = &match,
  86         .checkentry     = &ip6t_eui64_checkentry,
  87         .me             = THIS_MODULE,
  88 };
  89
  90 static int __init init(void)
  91 {
  92         return ip6t_register_match(&eui64_match);
  93 }
  94
  95 static void __exit fini(void)
  96 {
  97         ip6t_unregister_match(&eui64_match);
  98 }
  99
 100 module_init(init);
 101 module_exit(fini);