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#ifndef __LINUX_BRIDGE_EBT_AMONG_H

#define __LINUX_BRIDGE_EBT_AMONG_H

#include <linux/types.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 {

        __u32 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