30 lines
1.1 KiB
C
30 lines
1.1 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* cksum.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: jhalford <jack@crans.org> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2017/10/08 12:45:43 by jhalford #+# #+# */
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/* Updated: 2017/10/08 12:48:41 by jhalford ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include "net.h"
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unsigned short cksum(const void *b, size_t len)
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{
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unsigned int sum;
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sum = 0;
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while (len > 1)
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{
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sum += *((uint16_t*)b++);
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b++;
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len -= 2;
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}
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if (len == 1)
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sum += *(uint8_t*)b;
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while (sum >> 16) sum = (sum & 0xFFFF)+(sum >> 16);
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return (~sum);
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}
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