Add support for zero packet loss in PROX L3 mode.

In L3 mode, prox is extracting IP destination address in the packets.
It uses this destination address to find the MAC address.
If the MAC address is not found, it sends a ARP request.

It also sends ARP request when it realizes that some timeout expired.
However, PROX was using the mbuf of the existing packets (to be forwarded)
to send the ARP. This resulted in packet loss.

Now PROX is generating ARP requests using mbuf from an ARP mempool.
Some clean up was also done.

Change-Id: Icb6083a8cdf88789553ad23c32ca12d6b7ba7f08
Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>

1 files changed, 20 insertions, 3 deletions

diff --git a/VNFs/DPPD-PROX/tx_pkt.c b/VNFs/DPPD-PROX/tx_pkt.c
index b8c74a68..c5047e56 100644
--- a/VNFs/DPPD-PROX/tx_pkt.c
+++ b/VNFs/DPPD-PROX/tx_pkt.c
@@ -55,22 +55,39 @@ int tx_pkt_l3(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts,
 	uint32_t ip_dst;
 	int first = 0, ret, ok = 0, rc;
 	const struct port_queue *port_queue = &tbase->tx_params_hw.tx_port_queue[0];
+	struct rte_mbuf *arp_mbuf = NULL;       // used when one need to send both an ARP and a mbuf
 
 	for (int j = 0; j < n_pkts; j++) {
 		if ((out) && (out[j] >= OUT_HANDLED))
 			continue;
-		if (unlikely((rc = write_dst_mac(tbase, mbufs[j], &ip_dst)) < 0)) {
+		if (unlikely((rc = write_dst_mac(tbase, mbufs[j], &ip_dst)) != SEND_MBUF)) {
 			if (j - first) {
 				ret = tbase->aux->tx_pkt_l2(tbase, mbufs + first, j - first, out);
 				ok += ret;
 			}
 			first = j + 1;
-			if (rc == -1) {
+			switch(rc) {
+			case SEND_ARP:
+				// We re-use the mbuf - no need to create a arp_mbuf and delete the existing mbuf
 				mbufs[j]->port = tbase->l3.reachable_port_id;
 				tx_ring_cti(tbase, tbase->l3.ctrl_plane_ring, REQ_MAC_TO_CTRL, mbufs[j], tbase->l3.core_id, tbase->l3.task_id, ip_dst);
-			} else if (rc == -2) {
+				break;
+			case SEND_MBUF_AND_ARP:
+				// We send the mbuf and an ARP - we need to allocate another mbuf for ARP
+				ret = rte_mempool_get(tbase->l3.arp_pool, (void **)&arp_mbuf);
+				if (likely(ret == 0))   {
+					arp_mbuf->port = tbase->l3.reachable_port_id;
+					tx_ring_cti(tbase, tbase->l3.ctrl_plane_ring, REQ_MAC_TO_CTRL, arp_mbuf, tbase->l3.core_id, tbase->l3.task_id, ip_dst);
+				} else {
+					plog_err("Failed to get a mbuf from arp mempool\n");
+					// We still send the initial mbuf
+				}
+				ret = tbase->aux->tx_pkt_l2(tbase, mbufs + j, 1, out);
+				break;
+			case DROP_MBUF:
 				tx_drop(mbufs[j]);
 				TASK_STATS_ADD_DROP_DISCARD(&tbase->aux->stats, 1);
+				break;
 			}
 		}
 	}