FM / netfilter

/usr/include/linux/netfilter_bridge

Name	Size	Mode	Actions
ebtables.h	8958	0644	edit dl rm
ebt_802_3.h	1147	0644	edit dl rm
ebt_among.h	1957	0644	edit dl rm
ebt_arp.h	789	0644	edit dl rm
ebt_arpreply.h	197	0644	edit dl rm
ebt_ip.h	849	0644	edit dl rm
ebt_limit.h	543	0644	edit dl rm
ebt_log.h	458	0644	edit dl rm
ebt_mark_m.h	305	0644	edit dl rm
ebt_mark_t.h	768	0644	edit dl rm
ebt_nat.h	295	0644	edit dl rm
ebt_pkttype.h	184	0644	edit dl rm
ebt_redirect.h	223	0644	edit dl rm
ebt_stp.h	1057	0644	edit dl rm
ebt_ulog.h	952	0644	edit dl rm
ebt_vlan.h	642	0644	edit dl rm

Edit: /usr/include/linux/netfilter_bridge/ebt_among.h (1957B)

#ifndef __LINUX_BRIDGE_EBT_AMONG_H
#define __LINUX_BRIDGE_EBT_AMONG_H

#define EBT_AMONG_DST 0x01
#define EBT_AMONG_SRC 0x02

/* Grzegorz Borowiak <grzes@gnu.univ.gda.pl> 2003
 * 
 * Write-once-read-many hash table, used for checking if a given
 * MAC address belongs to a set or not and possibly for checking
 * if it is related with a given IPv4 address.
 *
 * The hash value of an address is its last byte.
 * 
 * In real-world ethernet addresses, values of the last byte are
 * evenly distributed and there is no need to consider other bytes.
 * It would only slow the routines down.
 *
 * For MAC address comparison speedup reasons, we introduce a trick.
 * MAC address is mapped onto an array of two 32-bit integers.
 * This pair of integers is compared with MAC addresses in the
 * hash table, which are stored also in form of pairs of integers
 * (in `cmp' array). This is quick as it requires only two elementary
 * number comparisons in worst case. Further, we take advantage of
 * fact that entropy of 3 last bytes of address is larger than entropy
 * of 3 first bytes. So first we compare 4 last bytes of addresses and
 * if they are the same we compare 2 first.
 *
 * Yes, it is a memory overhead, but in 2003 AD, who cares?
 */

struct ebt_mac_wormhash_tuple
{
	uint32_t cmp[2];
	__be32 ip;
};

struct ebt_mac_wormhash
{
	int table[257];
	int poolsize;
	struct ebt_mac_wormhash_tuple pool[0];
};

#define ebt_mac_wormhash_size(x) ((x) ? sizeof(struct ebt_mac_wormhash) \
		+ (x)->poolsize * sizeof(struct ebt_mac_wormhash_tuple) : 0)

struct ebt_among_info
{
	int wh_dst_ofs;
	int wh_src_ofs;
	int bitmask;
};

#define EBT_AMONG_DST_NEG 0x1
#define EBT_AMONG_SRC_NEG 0x2

#define ebt_among_wh_dst(x) ((x)->wh_dst_ofs ? \
	(struct ebt_mac_wormhash*)((char*)(x) + (x)->wh_dst_ofs) : NULL)
#define ebt_among_wh_src(x) ((x)->wh_src_ofs ? \
	(struct ebt_mac_wormhash*)((char*)(x) + (x)->wh_src_ofs) : NULL)

#define EBT_AMONG_MATCH "among"

#endif

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