Prevent dropping ARP packets

JIRA: SAMPLEVNF-152

When system is overloaded, ARP packets were sometimes dropped, as any
other packets.
This was causing two issues:
- The count of TX non dataplane packets was wrong
- If many consecutive ARP packets were dropped, the underlying switch might
  see its ARP timer expiring, causing performance degradation (packets being
  broadcasted).
ARP packets are now always sent as no-drop.

Change-Id: I9a86cbf8c4b56a178f86bc789153f1fa49ddf73f
Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>

5 files changed, 47 insertions, 13 deletions

diff --git a/VNFs/DPPD-PROX/packet_utils.c b/VNFs/DPPD-PROX/packet_utils.c
index e93f430c..274d2f84 100644
--- a/VNFs/DPPD-PROX/packet_utils.c
+++ b/VNFs/DPPD-PROX/packet_utils.c
@@ -325,9 +325,10 @@ void handle_ctrl_plane_pkts(struct task_base *tbase, struct rte_mbuf **mbufs, ui
 			break;
 		case ARP_REPLY_FROM_CTRL:
 		case ARP_REQ_FROM_CTRL:
-			TASK_STATS_ADD_TX_NON_DP(&tbase->aux->stats, 1);
 			out[0] = 0;
-			tbase->aux->tx_pkt_l2(tbase, &mbufs[j], 1, out);
+			// tx_ctrlplane_pkt does not drop packets
+			tbase->aux->tx_ctrlplane_pkt(tbase, &mbufs[j], 1, out);
+			TASK_STATS_ADD_TX_NON_DP(&tbase->aux->stats, 1);
 			break;
 		}
 	}
diff --git a/VNFs/DPPD-PROX/task_base.h b/VNFs/DPPD-PROX/task_base.h
index b4a33372..64d17436 100644
--- a/VNFs/DPPD-PROX/task_base.h
+++ b/VNFs/DPPD-PROX/task_base.h
@@ -174,6 +174,7 @@ struct task_base_aux {
 	int (*tx_pkt_hw)(struct task_base *tbase, struct rte_mbuf **mbufs, const uint16_t n_pkts, uint8_t *out);
 	uint16_t (*tx_pkt_try)(struct task_base *tbase, struct rte_mbuf **mbufs, const uint16_t n_pkts);
 	void (*stop)(struct task_base *tbase);
+	int (*tx_ctrlplane_pkt)(struct task_base *tbase, struct rte_mbuf **mbufs, const uint16_t n_pkts, uint8_t *out);
 	void (*start)(struct task_base *tbase);
 	void (*stop_last)(struct task_base *tbase);
 	void (*start_first)(struct task_base *tbase);
diff --git a/VNFs/DPPD-PROX/task_init.c b/VNFs/DPPD-PROX/task_init.c
index 2361d32c..08ccaf97 100644
--- a/VNFs/DPPD-PROX/task_init.c
+++ b/VNFs/DPPD-PROX/task_init.c
@@ -208,7 +208,7 @@ static size_t init_rx_tx_rings_ports(struct task_args *targ, struct task_base *t
 	if ((targ->nb_txrings != 0) && (!targ->tx_opt_ring) && (!(targ->flags & TASK_ARG_DROP))) {
 		// Transmitting to a ring in NO DROP. We need to make sure the receiving task in not running on the same core.
 		// Otherwise we might end up in a dead lock: trying in a loop to transmit to a task which cannot receive anymore
-		// (as npt being scheduled).
+		// (as not being scheduled).
 		struct core_task ct;
 		struct task_args *dtarg;
 		for (unsigned int j = 0; j < targ->nb_txrings; j++) {
@@ -277,6 +277,7 @@ static size_t init_rx_tx_rings_ports(struct task_args *targ, struct task_base *t
 			prev = prev->tx_opt_ring_task;
 		}
 	}
+
 	if (targ->nb_txrings == 1 || targ->nb_txports == 1 || targ->tx_opt_ring) {
 		if (targ->task_init->flag_features & TASK_FEATURE_NEVER_DISCARDS) {
 			if (targ->tx_opt_ring) {
@@ -350,13 +351,6 @@ struct task_base *init_task_struct(struct task_args *targ)
 	offset = init_rx_tx_rings_ports(targ, tbase, offset);
 	tbase->aux = (struct task_base_aux *)(((uint8_t *)tbase) + offset);
 
-	if (targ->nb_txports != 0) {
-		if (targ->flags & TASK_ARG_L3) {
-			tbase->aux->tx_pkt_l2 = tbase->tx_pkt;
-			tbase->tx_pkt = tx_pkt_l3;
-		}
-	}
-
 	if (targ->task_init->flag_features & TASK_FEATURE_RX_ALL) {
 		task_base_add_rx_pkt_function(tbase, rx_pkt_all);
 		tbase->aux->all_mbufs = prox_zmalloc(MAX_RX_PKT_ALL * sizeof(* tbase->aux->all_mbufs), task_socket);
@@ -372,10 +366,13 @@ struct task_base *init_task_struct(struct task_args *targ)
 	if (targ->flags & TASK_ARG_L3) {
 		plog_info("\tTask configured in L3 mode\n");
 		tbase->l3.ctrl_plane_ring = targ->ctrl_plane_ring;
-	}
-	if (targ->nb_txports != 0) {
-		if (targ->flags & TASK_ARG_L3)
+		if (targ->nb_txports != 0) {
+			tbase->aux->tx_pkt_l2 = tbase->tx_pkt;
+			tbase->tx_pkt = tx_pkt_l3;
+			// Make sure control plane packets such as arp are not dropped
+			tbase->aux->tx_ctrlplane_pkt = targ->nb_txrings ? tx_ctrlplane_sw : tx_ctrlplane_hw;
 			task_init_l3(tbase, targ);
+		}
 	}
 
 	targ->tbase = tbase;
diff --git a/VNFs/DPPD-PROX/tx_pkt.c b/VNFs/DPPD-PROX/tx_pkt.c
index c5047e56..d494236c 100644
--- a/VNFs/DPPD-PROX/tx_pkt.c
+++ b/VNFs/DPPD-PROX/tx_pkt.c
@@ -762,6 +762,39 @@ int tx_pkt_drop_all(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n
 	}
 	return n_pkts;
 }
+static inline void dump_pkts(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts)
+{
+	uint32_t n_dump = tbase->aux->task_rt_dump.n_print_tx;
+	uint32_t n_trace = tbase->aux->task_rt_dump.n_trace;
+
+	if (unlikely(n_dump)) {
+		n_dump = n_pkts < n_dump? n_pkts : n_dump;
+		for (uint32_t i = 0; i < n_dump; ++i) {
+			plogdx_info(mbufs[i], "TX: ");
+		}
+		tbase->aux->task_rt_dump.n_print_tx -= n_dump;
+	} else if (unlikely(n_trace)) {
+		n_trace = n_pkts < n_trace? n_pkts : n_trace;
+		for (uint32_t i = 0; i < n_trace; ++i) {
+			plogdx_info(mbufs[i], "TX: ");
+		}
+		tbase->aux->task_rt_dump.n_trace - n_trace;
+	}
+}
+
+// ctrlplane packets are slow path, hence cost of checking if dump ortrace is needed in not too important
+// easier to have this implementation than an implementation similar to dataplane tx
+int tx_ctrlplane_hw(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts, __attribute__((unused)) uint8_t *out)
+{
+	dump_pkts(tbase, mbufs, n_pkts);
+	return txhw_no_drop(&tbase->tx_params_hw.tx_port_queue[0], mbufs, n_pkts, tbase);
+}
+
+int tx_ctrlplane_sw(struct task_base *tbase, struct rte_mbuf **mbufs, const uint16_t n_pkts, __attribute__((unused)) uint8_t *out)
+{
+	dump_pkts(tbase, mbufs, n_pkts);
+        return ring_enq_no_drop(tbase->tx_params_sw.tx_rings[0], mbufs, n_pkts, tbase);
+}
 
 static inline int tx_ring_all(struct task_base *tbase, struct rte_ring *ring, uint16_t command,  struct rte_mbuf *mbuf, uint8_t core_id, uint8_t task_id, uint32_t ip)
 {
diff --git a/VNFs/DPPD-PROX/tx_pkt.h b/VNFs/DPPD-PROX/tx_pkt.h
index e8caed52..a6881531 100644
--- a/VNFs/DPPD-PROX/tx_pkt.h
+++ b/VNFs/DPPD-PROX/tx_pkt.h
@@ -64,6 +64,8 @@ int tx_pkt_no_drop_hw(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t
 int tx_pkt_no_drop_sw(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts, uint8_t *out);
 int tx_pkt_hw(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts, uint8_t *out);
 int tx_pkt_sw(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts, uint8_t *out);
+int tx_ctrlplane_hw(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts, uint8_t *out);
+int tx_ctrlplane_sw(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts, uint8_t *out);
 
 int tx_pkt_trace(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts, uint8_t *out);
 int tx_pkt_dump(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts, uint8_t *out);