net/bridge/netfilter/ebt_802_3.c

   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
  15 static bool
  16 ebt_802_3_mt(const struct sk_buff *skb, struct xt_action_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
  39 static int 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 -EINVAL;
  45
  46         return 0;
  47 }
  48
  49 static 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      = sizeof(struct ebt_802_3_info),
  56         .me             = THIS_MODULE,
  57 };
  58
  59 static int __init ebt_802_3_init(void)
  60 {
  61         return xt_register_match(&ebt_802_3_mt_reg);
  62 }
  63
  64 static void __exit ebt_802_3_fini(void)
  65 {
  66         xt_unregister_match(&ebt_802_3_mt_reg);
  67 }
  68
  69 module_init(ebt_802_3_init);
  70 module_exit(ebt_802_3_fini);
  71 MODULE_DESCRIPTION("Ebtables: DSAP/SSAP field and SNAP type matching");
  72 MODULE_LICENSE("GPL");