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/**
* @file IxEthDBLearning.c
*
* @par
* IXP400 SW Release version 2.0
*
* -- Copyright Notice --
*
* @par
* Copyright 2001-2005, Intel Corporation.
* All rights reserved.
*
* @par
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Intel Corporation nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* @par
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @par
* -- End of Copyright Notice --
*/
#include "IxEthDB_p.h"
/**
* @brief hashes the mac address in a mac descriptor with a XOR function
*
* @param entry pointer to a mac descriptor to be hashed
*
* This function only extracts the mac address and employs ixEthDBKeyXORHash()
* to do the actual hashing.
* Used only to add a whole entry to a hash table, as opposed to searching which
* takes only a key and uses the key hashing directly.
*
* @see ixEthDBKeyXORHash()
*
* @return the hash value
*
* @internal
*/
UINT32 ixEthDBEntryXORHash(void *entry)
{
MacDescriptor *descriptor = (MacDescriptor *) entry;
return ixEthDBKeyXORHash(descriptor->macAddress);
}
/**
* @brief hashes a mac address
*
* @param key pointer to a 6 byte structure (typically an IxEthDBMacAddr pointer)
* to be hashed
*
* Given a 6 bytes MAC address, the hash used is:
*
* hash(MAC[0:5]) = MAC[0:1] ^ MAC[2:3] ^ MAC[4:5]
*
* Used by the hash table to search and remove entries based
* solely on their keys (mac addresses).
*
* @return the hash value
*
* @internal
*/
UINT32 ixEthDBKeyXORHash(void *key)
{
UINT32 hashValue;
UINT8 *value = (UINT8 *) key;
hashValue = (value[5] << 8) | value[4];
hashValue ^= (value[3] << 8) | value[2];
hashValue ^= (value[1] << 8) | value[0];
return hashValue;
}
/**
* @brief mac descriptor match function
*
* @param reference mac address (typically an IxEthDBMacAddr pointer) structure
* @param entry pointer to a mac descriptor whose key (mac address) is to be
* matched against the reference key
*
* Used by the hash table to retrieve entries. Hashing entries can produce
* collisions, i.e. descriptors with different mac addresses and the same
* hash value, where this function is used to differentiate entries.
*
* @retval true if the entry matches the reference key (equal addresses)
* @retval false if the entry does not match the reference key
*
* @internal
*/
BOOL ixEthDBAddressMatch(void *reference, void *entry)
{
return (ixEthDBAddressCompare(reference, ((MacDescriptor *) entry)->macAddress) == 0);
}
/**
* @brief compares two mac addresses
*
* @param mac1 first mac address to compare
* @param mac2 second mac address to compare
*
* This comparison works in a similar way to strcmp, producing similar results.
* Used to insert values keyed on mac addresses into binary search trees.
*
* @retval -1 if mac1 < mac2
* @retval 0 if ma1 == mac2
* @retval 1 if mac1 > mac2
*/
UINT32 ixEthDBAddressCompare(UINT8 *mac1, UINT8 *mac2)
{
UINT32 local_index;
for (local_index = 0 ; local_index < IX_IEEE803_MAC_ADDRESS_SIZE ; local_index++)
{
if (mac1[local_index] > mac2[local_index])
{
return 1;
}
else if (mac1[local_index] < mac2[local_index])
{
return -1;
}
}
return 0;
}
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