LXR linux/net/bridge/netfilter/ebt_802

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * 802_3
   4 *
   5 * Author:
   6 * Chris Vitale csv@bluetail.com
   7 *
   8 * May 2003
   9 *
  10 */
  11#include <linux/module.h>
  12#include <linux/netfilter/x_tables.h>
  13#include <linux/netfilter_bridge/ebtables.h>
  14#include <linux/netfilter_bridge/ebt_802_3.h>
  15
  16static bool
  17ebt_802_3_mt(const struct sk_buff *skb, struct xt_action_param *par)
  18{
  19        const struct ebt_802_3_info *info = par->matchinfo;
  20        const struct ebt_802_3_hdr *hdr = ebt_802_3_hdr(skb);
  21        __be16 type = hdr->llc.ui.ctrl & IS_UI ? hdr->llc.ui.type : hdr->llc.ni.type;
  22
  23        if (info->bitmask & EBT_802_3_SAP) {
  24                if (NF_INVF(info, EBT_802_3_SAP, info->sap != hdr->llc.ui.ssap))
  25                        return false;
  26                if (NF_INVF(info, EBT_802_3_SAP, info->sap != hdr->llc.ui.dsap))
  27                        return false;
  28        }
  29
  30        if (info->bitmask & EBT_802_3_TYPE) {
  31                if (!(hdr->llc.ui.dsap == CHECK_TYPE && hdr->llc.ui.ssap == CHECK_TYPE))
  32                        return false;
  33                if (NF_INVF(info, EBT_802_3_TYPE, info->type != type))
  34                        return false;
  35        }
  36
  37        return true;
  38}
  39
  40static int ebt_802_3_mt_check(const struct xt_mtchk_param *par)
  41{
  42        const struct ebt_802_3_info *info = par->matchinfo;
  43
  44        if (info->bitmask & ~EBT_802_3_MASK || info->invflags & ~EBT_802_3_MASK)
  45                return -EINVAL;
  46
  47        return 0;
  48}
  49
  50static struct xt_match ebt_802_3_mt_reg __read_mostly = {
  51        .name           = "802_3",
  52        .revision       = 0,
  53        .family         = NFPROTO_BRIDGE,
  54        .match          = ebt_802_3_mt,
  55        .checkentry     = ebt_802_3_mt_check,
  56        .matchsize      = sizeof(struct ebt_802_3_info),
  57        .me             = THIS_MODULE,
  58};
  59
  60static int __init ebt_802_3_init(void)
  61{
  62        return xt_register_match(&ebt_802_3_mt_reg);
  63}
  64
  65static void __exit ebt_802_3_fini(void)
  66{
  67        xt_unregister_match(&ebt_802_3_mt_reg);
  68}
  69
  70module_init(ebt_802_3_init);
  71module_exit(ebt_802_3_fini);
  72MODULE_DESCRIPTION("Ebtables: DSAP/SSAP field and SNAP type matching");
  73MODULE_LICENSE("GPL");
  74