[dpdk-dev] [PATCH v2 3/4] examples/vhost: fix offload settings

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

Comments for PKT_TX_TCP_SEG at rte_mbuf says that we should only set
PKT_TX_IP_CKSUM and reset ip hdr checksum for IPv4:

  - if it's IPv4, set the PKT_TX_IP_CKSUM flag and write the IP checksum
    to 0 in the packet

Fixes: 9fd72e3cbd29 ("examples/vhost: add virtio offload")

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
---
 examples/vhost/main.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index ceabbce..86e5c24 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -1163,10 +1163,13 @@ static void virtio_tx_offload(struct rte_mbuf *m)
 
 	l3_hdr = (char *)eth_hdr + m->l2_len;
 
-	ipv4_hdr = (struct ipv4_hdr *)l3_hdr;
+	if (m->ol_flags & PKT_TX_IPV4) {
+		ipv4_hdr = l3_hdr;
+		ipv4_hdr->hdr_checksum = 0;
+		m->ol_flags |= PKT_TX_IP_CKSUM;
+	}
+
 	tcp_hdr = (struct tcp_hdr *)((char *)l3_hdr + m->l3_len);
-	m->ol_flags |= PKT_TX_IP_CKSUM;
-	ipv4_hdr->hdr_checksum = 0;
 	tcp_hdr->cksum = get_psd_sum(l3_hdr, m->ol_flags);
 }
 
-- 
1.9.0