[dpdk-dev] [PATCH] vhost: Fix packet length issue

[Ouyang Changchun <changchun.ouyang@intel.com>]

As HW vlan strip will reduce the packet length by minus length of vlan tag,
so it need restore the packet length by plus it.

Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
---
 examples/vhost/main.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index 0566124..dc32fa9 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -1067,6 +1067,7 @@ virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
 {
 	struct mbuf_table *tx_q;
 	struct rte_mbuf **m_table;
+	struct rte_mbuf *last_seg = m;
 	unsigned len, ret, offset = 0;
 	const uint16_t lcore_id = rte_lcore_id();
 	struct virtio_net_data_ll *dev_ll = ll_root_used;
@@ -1097,7 +1098,13 @@ virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
 					rte_pktmbuf_free(m);
 					return;
 				}
-				offset = 4;
+
+				/*
+				 * HW vlan strip will reduce the packet length
+				 * by minus length of vlan tag, so need restore
+				 * the packet length by plus it.
+				 */
+				offset = VLAN_HLEN;
 				vlan_tag =
 				(uint16_t)
 				vlan_tags[(uint16_t)dev_ll->vdev->dev->device_fh];
@@ -1121,8 +1128,12 @@ virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
 	len = tx_q->len;
 
 	m->ol_flags = PKT_TX_VLAN_PKT;
-	/*FIXME: offset*/
-	m->data_len += offset;
+
+	while (last_seg->next)
+		last_seg = last_seg->next;
+	last_seg->data_len += offset;
+	m->pkt_len += offset;
+
 	m->vlan_tci = vlan_tag;
 
 	tx_q->m_table[len] = m;
-- 
1.8.4.2