LXR linux/net/bridge/netfilter/ebt_802

   1/*
   2 * 802_3
   3 *
   4 * Author:
   5 * Chris Vitale csv@bluetail.com
   6 *
   7 * May 2003
   8 *
   9 */
  10#include <linux/module.h>
  11#include <linux/netfilter/x_tables.h>
  12#include <linux/netfilter_bridge/ebtables.h>
  13#include <linux/netfilter_bridge/ebt_802_3.h>
  14
  15static bool
  16ebt_802_3_mt(const struct sk_buff *skb, const struct xt_match_param *par)
  17{
  18        const struct ebt_802_3_info *info = par->matchinfo;
  19        const struct ebt_802_3_hdr *hdr = ebt_802_3_hdr(skb);
  20        __be16 type = hdr->llc.ui.ctrl & IS_UI ? hdr->llc.ui.type : hdr->llc.ni.type;
  21
  22        if (info->bitmask & EBT_802_3_SAP) {
  23                if (FWINV(info->sap != hdr->llc.ui.ssap, EBT_802_3_SAP))
  24                        return false;
  25                if (FWINV(info->sap != hdr->llc.ui.dsap, EBT_802_3_SAP))
  26                        return false;
  27        }
  28
  29        if (info->bitmask & EBT_802_3_TYPE) {
  30                if (!(hdr->llc.ui.dsap == CHECK_TYPE && hdr->llc.ui.ssap == CHECK_TYPE))
  31                        return false;
  32                if (FWINV(info->type != type, EBT_802_3_TYPE))
  33                        return false;
  34        }
  35
  36        return true;
  37}
  38
  39static bool ebt_802_3_mt_check(const struct xt_mtchk_param *par)
  40{
  41        const struct ebt_802_3_info *info = par->matchinfo;
  42
  43        if (info->bitmask & ~EBT_802_3_MASK || info->invflags & ~EBT_802_3_MASK)
  44                return false;
  45
  46        return true;
  47}
  48
  49static struct xt_match ebt_802_3_mt_reg __read_mostly = {
  50        .name           = "802_3",
  51        .revision       = 0,
  52        .family         = NFPROTO_BRIDGE,
  53        .match          = ebt_802_3_mt,
  54        .checkentry     = ebt_802_3_mt_check,
  55        .matchsize      = XT_ALIGN(sizeof(struct ebt_802_3_info)),
  56        .me             = THIS_MODULE,
  57};
  58
  59static int __init ebt_802_3_init(void)
  60{
  61        return xt_register_match(&ebt_802_3_mt_reg);
  62}
  63
  64static void __exit ebt_802_3_fini(void)
  65{
  66        xt_unregister_match(&ebt_802_3_mt_reg);
  67}
  68
  69module_init(ebt_802_3_init);
  70module_exit(ebt_802_3_fini);
  71MODULE_DESCRIPTION("Ebtables: DSAP/SSAP field and SNAP type matching");
  72MODULE_LICENSE("GPL");
  73