1 /* (C) 1999-2001 Michal Ludvig <michal@logix.cz> 2 * 3 * This program is free software; you can redistribute it and/or modify 4 * it under the terms of the GNU General Public License version 2 as 5 * published by the Free Software Foundation. 6 */ 7 8 #include <linux/module.h> 9 #include <linux/skbuff.h> 10 #include <linux/if_ether.h> 11 #include <linux/if_packet.h> 12 #include <linux/in.h> 13 #include <linux/ip.h> 14 #include <linux/ipv6.h> 15 16 #include <linux/netfilter/xt_pkttype.h> 17 #include <linux/netfilter/x_tables.h> 18 19 MODULE_LICENSE("GPL"); 20 MODULE_AUTHOR("Michal Ludvig <michal@logix.cz>"); 21 MODULE_DESCRIPTION("Xtables: link layer packet type match"); 22 MODULE_ALIAS("ipt_pkttype"); 23 MODULE_ALIAS("ip6t_pkttype"); 24 25 static bool 26 pkttype_mt(const struct sk_buff *skb, const struct net_device *in, 27 const struct net_device *out, const struct xt_match *match, 28 const void *matchinfo, int offset, unsigned int protoff, 29 bool *hotdrop) 30 { 31 const struct xt_pkttype_info *info = matchinfo; 32 u_int8_t type; 33 34 if (skb->pkt_type != PACKET_LOOPBACK) 35 type = skb->pkt_type; 36 else if (match->family == AF_INET && 37 ipv4_is_multicast(ip_hdr(skb)->daddr)) 38 type = PACKET_MULTICAST; 39 else if (match->family == AF_INET6 && 40 ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF) 41 type = PACKET_MULTICAST; 42 else 43 type = PACKET_BROADCAST; 44 45 return (type == info->pkttype) ^ info->invert; 46 } 47 48 static struct xt_match pkttype_mt_reg[] __read_mostly = { 49 { 50 .name = "pkttype", 51 .family = AF_INET, 52 .match = pkttype_mt, 53 .matchsize = sizeof(struct xt_pkttype_info), 54 .me = THIS_MODULE, 55 }, 56 { 57 .name = "pkttype", 58 .family = AF_INET6, 59 .match = pkttype_mt, 60 .matchsize = sizeof(struct xt_pkttype_info), 61 .me = THIS_MODULE, 62 }, 63 }; 64 65 static int __init pkttype_mt_init(void) 66 { 67 return xt_register_matches(pkttype_mt_reg, ARRAY_SIZE(pkttype_mt_reg)); 68 } 69 70 static void __exit pkttype_mt_exit(void) 71 { 72 xt_unregister_matches(pkttype_mt_reg, ARRAY_SIZE(pkttype_mt_reg)); 73 } 74 75 module_init(pkttype_mt_init); 76 module_exit(pkttype_mt_exit); 77