36 lines
676 B
C
36 lines
676 B
C
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <wchar.h>
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#include <time.h>
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#define HAVE_STDARG_H
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/*
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* Return the 6-bit index into the multicast
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* table. Stolen unashamedly from FreeBSD's if_ed.c
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*/
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int
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mcast_index(const void *dst)
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{
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#define POLYNOMIAL 0x04c11db6
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uint32_t crc = 0xffffffffL;
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int carry, i, j;
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uint8_t b;
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uint8_t *ep = (uint8_t *)dst;
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for (i=6; --i>=0;) {
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b = *ep++;
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for (j = 8; --j >= 0;) {
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carry = ((crc & 0x80000000L) ? 1 : 0) ^ (b & 0x01);
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crc <<= 1;
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b >>= 1;
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if (carry)
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crc = ((crc ^ POLYNOMIAL) | carry);
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}
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}
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return(crc >> 26);
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#undef POLYNOMIAL
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}
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