Function simulate_add_step

dpdk/lib/lpm/rte_lpm6.c:595–640

* Simulate adding a new route to the LPM counting number * of new tables that will be needed * * It returns 0 on success, or 1 if * the process needs to be continued by calling the function again. */

 * the process needs to be continued by calling the function again.
 */
static inline int
simulate_add_step(struct rte_lpm6 *lpm, struct rte_lpm6_tbl_entry *tbl,
		struct rte_lpm6_tbl_entry **next_tbl, const uint8_t *ip,
		uint8_t bytes, uint8_t first_byte, uint8_t depth,
		uint32_t *need_tbl_nb)
{
	uint32_t entry_ind;
	uint8_t bits_covered;
	uint32_t next_tbl_ind;

	/*
	 * Calculate index to the table based on the number and position
	 * of the bytes being inspected in this step.
	 */
	entry_ind = get_bitshift(ip, first_byte, bytes);

	/* Number of bits covered in this step */
	bits_covered = (uint8_t)((bytes+first_byte-1)*BYTE_SIZE);

	if (depth <= bits_covered) {
		*need_tbl_nb = 0;
		return 0;
	}

	if (tbl[entry_ind].valid == 0 || tbl[entry_ind].ext_entry == 0) {
		/* from this point on a new table is needed on each level
		 * that is not covered yet
		 */
		depth -= bits_covered;
		uint32_t cnt = depth >> 3; /* depth / BYTE_SIZE */
		if (depth & 7) /* 0b00000111 */
			/* if depth % 8 > 0 then one more table is needed
			 * for those last bits
			 */
			cnt++;

		*need_tbl_nb = cnt;
		return 0;
	}

	next_tbl_ind = tbl[entry_ind].lpm6_tbl8_gindex;
	*next_tbl = &(lpm->tbl8[next_tbl_ind *
		RTE_LPM6_TBL8_GROUP_NUM_ENTRIES]);
	*need_tbl_nb = 0;
	return 1;
}

/*
 * Partially adds a new route to the data structure (tbl24+tbl8s).