Function rte_lpm_lookup

dpdk/lib/lpm/rte_lpm.h:277–309

* Lookup an IP into the LPM table. * * @param lpm * LPM object handle * @param ip * IP to be looked up in the LPM table * @param next_hop * Next hop of the most specific rule found for IP (valid on lookup hit only) * @return * -EINVAL for incorrect arguments, -ENOENT on lookup miss, 0 on lookup hit */

 *   -EINVAL for incorrect arguments, -ENOENT on lookup miss, 0 on lookup hit
 */
static inline int
rte_lpm_lookup(const struct rte_lpm *lpm, uint32_t ip, uint32_t *next_hop)
{
	unsigned tbl24_index = (ip >> 8);
	uint32_t tbl_entry;
	const uint32_t *ptbl;

	/* DEBUG: Check user input arguments. */
	RTE_LPM_RETURN_IF_TRUE(((lpm == NULL) || (next_hop == NULL)), -EINVAL);

	/* Copy tbl24 entry */
	ptbl = (const uint32_t *)(&lpm->tbl24[tbl24_index]);
	tbl_entry = *ptbl;

	/* Memory ordering is not required in lookup. Because dataflow
	 * dependency exists, compiler or HW won't be able to re-order
	 * the operations.
	 */
	/* Copy tbl8 entry (only if needed) */
	if (unlikely((tbl_entry & RTE_LPM_VALID_EXT_ENTRY_BITMASK) ==
			RTE_LPM_VALID_EXT_ENTRY_BITMASK)) {

		unsigned tbl8_index = (uint8_t)ip +
				(((uint32_t)tbl_entry & 0x00FFFFFF) *
						RTE_LPM_TBL8_GROUP_NUM_ENTRIES);

		ptbl = (const uint32_t *)&lpm->tbl8[tbl8_index];
		tbl_entry = *ptbl;
	}

	*next_hop = ((uint32_t)tbl_entry & 0x00FFFFFF);
	return (tbl_entry & RTE_LPM_LOOKUP_SUCCESS) ? 0 : -ENOENT;
}

/**
 * Lookup multiple IP addresses in an LPM table. This may be implemented as a