[dpdk-dev] [PATCH v2 20/24] example/vhost: Avoid inserting vlan twice

Ouyang Changchun changchun.ouyang at intel.com
Tue Jan 27 03:36:00 CET 2015


Check if it has already been vlan-tagged packet, if true, avoid inserting a
duplicated vlan tag into it.

This is a possible case when guest has the capability of inserting vlan tag.

Signed-off-by: Changchun Ouyang <changchun.ouyang at intel.com>
---
 examples/vhost/main.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index 04f0118..1d31520 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -1115,6 +1115,7 @@ virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
 	unsigned len, ret, offset = 0;
 	const uint16_t lcore_id = rte_lcore_id();
 	struct virtio_net *dev = vdev->dev;
+	struct ether_hdr *nh;
 
 	/*check if destination is local VM*/
 	if ((vm2vm_mode == VM2VM_SOFTWARE) && (virtio_tx_local(vdev, m) == 0)) {
@@ -1135,7 +1136,15 @@ virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
 	tx_q = &lcore_tx_queue[lcore_id];
 	len = tx_q->len;
 
-	m->ol_flags = PKT_TX_VLAN_PKT;
+	nh = rte_pktmbuf_mtod(m, struct ether_hdr *);
+	if (unlikely(nh->ether_type == rte_cpu_to_be_16(ETHER_TYPE_VLAN))) {
+		/* Guest has inserted the vlan tag. */
+		struct vlan_hdr *vh = (struct vlan_hdr *) (nh + 1);
+		uint16_t vlan_tag_be = rte_cpu_to_be_16(vlan_tag);
+		if (vh->vlan_tci != vlan_tag_be)
+			vh->vlan_tci = vlan_tag_be;
+	} else {
+		m->ol_flags = PKT_TX_VLAN_PKT;
 
 	/*
 	 * Find the right seg to adjust the data len when offset is
@@ -1156,7 +1165,8 @@ virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
 		m->pkt_len += offset;
 	}
 
-	m->vlan_tci = vlan_tag;
+		m->vlan_tci = vlan_tag;
+	}
 
 	tx_q->m_table[len] = m;
 	len++;
-- 
1.8.4.2



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