net/netfilter/xt_mac.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /* Kernel module to match MAC address parameters. */
0003
0004 /* (C) 1999-2001 Paul `Rusty' Russell
0005  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
0006  */
0007
0008 #include <linux/module.h>
0009 #include <linux/skbuff.h>
0010 #include <linux/if_arp.h>
0011 #include <linux/if_ether.h>
0012 #include <linux/etherdevice.h>
0013
0014 #include <linux/netfilter_ipv4.h>
0015 #include <linux/netfilter_ipv6.h>
0016 #include <linux/netfilter/xt_mac.h>
0017 #include <linux/netfilter/x_tables.h>
0018
0019 MODULE_LICENSE("GPL");
0020 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
0021 MODULE_DESCRIPTION("Xtables: MAC address match");
0022 MODULE_ALIAS("ipt_mac");
0023 MODULE_ALIAS("ip6t_mac");
0024
0025 static bool mac_mt(const struct sk_buff *skb, struct xt_action_param *par)
0026 {
0027     const struct xt_mac_info *info = par->matchinfo;
0028     bool ret;
0029
0030     if (skb->dev == NULL || skb->dev->type != ARPHRD_ETHER)
0031         return false;
0032     if (skb_mac_header(skb) < skb->head)
0033         return false;
0034     if (skb_mac_header(skb) + ETH_HLEN > skb->data)
0035         return false;
0036     ret  = ether_addr_equal(eth_hdr(skb)->h_source, info->srcaddr);
0037     ret ^= info->invert;
0038     return ret;
0039 }
0040
0041 static struct xt_match mac_mt_reg __read_mostly = {
0042     .name      = "mac",
0043     .revision  = 0,
0044     .family    = NFPROTO_UNSPEC,
0045     .match     = mac_mt,
0046     .matchsize = sizeof(struct xt_mac_info),
0047     .hooks     = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) |
0048                  (1 << NF_INET_FORWARD),
0049     .me        = THIS_MODULE,
0050 };
0051
0052 static int __init mac_mt_init(void)
0053 {
0054     return xt_register_match(&mac_mt_reg);
0055 }
0056
0057 static void __exit mac_mt_exit(void)
0058 {
0059     xt_unregister_match(&mac_mt_reg);
0060 }
0061
0062 module_init(mac_mt_init);
0063 module_exit(mac_mt_exit);