Function __rte_raw_cksum

dpdk/lib/net/rte_ip.h:160–182

* @internal Calculate a sum of all words in the buffer. * Helper routine for the rte_raw_cksum(). * * @param buf * Pointer to the buffer. * @param len * Length of the buffer. * @param sum * Initial value of the sum. * @return * sum += Sum of all words in the buffer. */

 *   sum += Sum of all words in the buffer.
 */
static inline uint32_t
__rte_raw_cksum(const void *buf, size_t len, uint32_t sum)
{
	const void *end;

	for (end = RTE_PTR_ADD(buf, RTE_ALIGN_FLOOR(len, sizeof(uint16_t)));
	     buf != end; buf = RTE_PTR_ADD(buf, sizeof(uint16_t))) {
		uint16_t v;

		memcpy(&v, buf, sizeof(uint16_t));
		sum += v;
	}

	/* if length is odd, keeping it byte order independent */
	if (unlikely(len % 2)) {
		uint16_t left = 0;

		memcpy(&left, end, 1);
		sum += left;
	}

	return sum;
}

/**
 * @internal Reduce a sum to the non-complemented checksum.