+ * Allocate a new mbuf with up to tx_pkt_nb_segs segments.
+ * 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 = random() % 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);
+ if (rc < 0)
+ TESTPMD_LOG(ERR,
+ "mbuf_copy_split for %p(len=%u, nb_seg=%u) "
+ "into %u segments failed with error code: %d\n",
+ pkt, pkt->pkt_len, pkt->nb_segs, nb_seg, rc);
+
+ /* figure out how many mbufs to free. */
+ i = RTE_MAX(rc, 0);
+ }
+
+ /* free unused mbufs */
+ for (; i != nb_seg; i++) {
+ rte_pktmbuf_free_seg(md[i]);
+ md[i] = NULL;
+ }
+
+ return md[0];
+}
+
+/*
+ * Receive a burst of packets, and for each packet:
+ * - parse packet, and try to recognize a supported packet type (1)
+ * - if it's not a supported packet type, don't touch the packet, else:
+ * - reprocess the checksum of all supported layers. This is done in SW
+ * or HW, depending on testpmd command line configuration
+ * - if TSO is enabled in testpmd command line, also flag the mbuf for TCP
+ * segmentation offload (this implies HW TCP checksum)
+ * Then transmit packets on the output port.
+ *
+ * (1) Supported packets are:
+ * Ether / (vlan) / IP|IP6 / UDP|TCP|SCTP .
+ * Ether / (vlan) / outer IP|IP6 / outer UDP / VxLAN / Ether / IP|IP6 /
+ * UDP|TCP|SCTP
+ * Ether / (vlan) / outer IP|IP6 / outer UDP / VXLAN-GPE / Ether / IP|IP6 /
+ * UDP|TCP|SCTP
+ * Ether / (vlan) / outer IP|IP6 / outer UDP / VXLAN-GPE / IP|IP6 /
+ * UDP|TCP|SCTP
+ * Ether / (vlan) / outer IP / outer UDP / GTP / IP|IP6 / UDP|TCP|SCTP
+ * Ether / (vlan) / outer IP|IP6 / GRE / Ether / IP|IP6 / UDP|TCP|SCTP
+ * Ether / (vlan) / outer IP|IP6 / GRE / IP|IP6 / UDP|TCP|SCTP
+ * Ether / (vlan) / outer IP|IP6 / IP|IP6 / UDP|TCP|SCTP
+ *
+ * The testpmd command line for this forward engine sets the flags
+ * TESTPMD_TX_OFFLOAD_* in ports[tx_port].tx_ol_flags. They control
+ * wether a checksum must be calculated in software or in hardware. The
+ * IP, UDP, TCP and SCTP flags always concern the inner layer. The
+ * OUTER_IP is only useful for tunnel packets.