[dpdk-dev] [PATCH v2] net/failsafe: fix source port ID in Rx packets

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

When passed to the application, Rx packets retain the port ID value
originally set by slave devices. Unfortunately these IDs have no meaning to
applications, which are typically unaware of their existence.

This confuses those caring about the source port field in mbufs (m->port)
which experience issues ranging from traffic drop to crashes.

Fixes: a46f8d584eb8 ("net/failsafe: add fail-safe PMD")
Cc: stable@dpdk.org

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>
Acked-by: Gaetan Rivet <gaetan.rivet@6wind.com>
--
v2 changes:

Modified "rxq->priv->dev->data->port_id" (v18.11-style) to
"rxq->priv->data->port_id" (since v19.05) and checked compilation against
master this time.

Given the limited scope of that change, reviewed-by/acked-by lines were
kept.
---
 drivers/net/failsafe/failsafe_rxtx.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/net/failsafe/failsafe_rxtx.c b/drivers/net/failsafe/failsafe_rxtx.c
index 231c83291..b9cddec78 100644
--- a/drivers/net/failsafe/failsafe_rxtx.c
+++ b/drivers/net/failsafe/failsafe_rxtx.c
@@ -61,6 +61,21 @@ failsafe_set_burst_fn(struct rte_eth_dev *dev, int force_safe)
 	rte_wmb();
 }
 
+/*
+ * Override source port in Rx packets.
+ *
+ * Make Rx packets originate from this PMD instance instead of one of its
+ * slaves. This is mandatory to avoid breaking applications.
+ */
+static void
+failsafe_rx_set_port(struct rte_mbuf **rx_pkts, uint16_t nb_pkts, uint16_t port)
+{
+	unsigned int i;
+
+	for (i = 0; i != nb_pkts; ++i)
+		rx_pkts[i]->port = port;
+}
+
 uint16_t
 failsafe_rx_burst(void *queue,
 		  struct rte_mbuf **rx_pkts,
@@ -87,6 +102,9 @@ failsafe_rx_burst(void *queue,
 		sdev = sdev->next;
 	} while (nb_rx == 0 && sdev != rxq->sdev);
 	rxq->sdev = sdev;
+	if (nb_rx)
+		failsafe_rx_set_port(rx_pkts, nb_rx,
+				     rxq->priv->data->port_id);
 	return nb_rx;
 }
 
@@ -112,6 +130,9 @@ failsafe_rx_burst_fast(void *queue,
 		sdev = sdev->next;
 	} while (nb_rx == 0 && sdev != rxq->sdev);
 	rxq->sdev = sdev;
+	if (nb_rx)
+		failsafe_rx_set_port(rx_pkts, nb_rx,
+				     rxq->priv->data->port_id);
 	return nb_rx;
 }
 
-- 
2.11.0