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Diffstat (limited to 'cpu/ixp/npe/IxEthDBLearning.c')
-rw-r--r-- | cpu/ixp/npe/IxEthDBLearning.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/cpu/ixp/npe/IxEthDBLearning.c b/cpu/ixp/npe/IxEthDBLearning.c new file mode 100644 index 00000000000..2287dbe96cf --- /dev/null +++ b/cpu/ixp/npe/IxEthDBLearning.c @@ -0,0 +1,149 @@ +/** + * @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; +} + |