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 16 static bool 17 ebt_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 40 static 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 50 static 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 60 static int __init ebt_802_3_init(void) 61 { 62 return xt_register_match(&ebt_802_3_mt_reg); 63 } 64 65 static void __exit ebt_802_3_fini(void) 66 { 67 xt_unregister_match(&ebt_802_3_mt_reg); 68 } 69 70 module_init(ebt_802_3_init); 71 module_exit(ebt_802_3_fini); 72 MODULE_DESCRIPTION("Ebtables: DSAP/SSAP field and SNAP type matching"); 73 MODULE_LICENSE("GPL"); 74