Function pkt_copy_split

dpdk/app/test-pmd/csumonly.c:709–784

* Allocate a new mbuf with up to tx_pkt_nb_segs segments. * Copy packet contents and offload information into the new segmented mbuf. */

 * Copy packet contents and offload information into the new segmented mbuf.
 */
static struct rte_mbuf *
pkt_copy_split(const struct rte_mbuf *pkt)
{
	int32_t n, rc;
	uint32_t i, len, nb_seg;
	struct rte_mempool *mp;
	uint16_t seglen[RTE_MAX_SEGS_PER_PKT];
	struct rte_mbuf *p, *md[RTE_MAX_SEGS_PER_PKT];

	mp = current_fwd_lcore()->mbp;

	if (tx_pkt_split == TX_PKT_SPLIT_RND)
		nb_seg = rte_rand() % tx_pkt_nb_segs + 1;
	else
		nb_seg = tx_pkt_nb_segs;

	memcpy(seglen, tx_pkt_seg_lengths, nb_seg * sizeof(seglen[0]));

	/* calculate number of segments to use and their length. */
	len = 0;
	for (i = 0; i != nb_seg && len < pkt->pkt_len; i++) {
		len += seglen[i];
		md[i] = NULL;
	}

	n = pkt->pkt_len - len;

	/* update size of the last segment to fit rest of the packet */
	if (n >= 0) {
		seglen[i - 1] += n;
		len += n;
	}

	nb_seg = i;
	while (i != 0) {
		p = rte_pktmbuf_alloc(mp);
		if (p == NULL) {
			TESTPMD_LOG(ERR,
				"failed to allocate %u-th of %u mbuf "
				"from mempool: %s\n",
				nb_seg - i, nb_seg, mp->name);
			break;
		}

		md[--i] = p;
		if (rte_pktmbuf_tailroom(md[i]) < seglen[i]) {
			TESTPMD_LOG(ERR, "mempool %s, %u-th segment: "
				"expected seglen: %u, "
				"actual mbuf tailroom: %u\n",
				mp->name, i, seglen[i],
				rte_pktmbuf_tailroom(md[i]));
			break;
		}
	}

	/* all mbufs successfully allocated, do copy */
	if (i == 0) {
		rc = mbuf_copy_split(pkt, md, seglen, nb_seg);