Re: [dpdk-dev] [PATCH] net: prepare the outer ipv4 hdr for checksum

-----Original Message-----
From: Mohsin Kazmi <redacted>
Sent: Tuesday 29 June 2021 18:07
To: dev@dpdk.org
Cc: Kinsella, Ray <redacted>; Mohsin Kazmi
[off-list ref]; stable@dpdk.org; Olivier Matz
[off-list ref]; Ananyev, Konstantin
[off-list ref]; Thomas Monjalon
[off-list ref]; Tomasz Kulasek [off-list ref]
Subject: [PATCH] net: prepare the outer ipv4 hdr for checksum

Preparation the headers for the hardware offload misses the outer ipv4
checksum offload.
It results in bad checksum computed by hardware NIC.

This patch fixes the issue by setting the outer ipv4 checksum field to
0.

Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
Cc: stable@dpdk.org

Signed-off-by: Mohsin Kazmi <redacted>
Acked-by: Qi Zhang <redacted>
---
 lib/net/rte_net.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h index

434435ffa2..e47365099e 100644

--- a/lib/net/rte_net.h
+++ b/lib/net/rte_net.h

@@ -128,8 +128,18 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf

*m, uint64_t ol_flags)
 	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK |
PKT_TX_TCP_SEG)))
 		return 0;

-	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
+	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
 		inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
+		/*
+		 * prepare outer ipv4 header checksum by setting it to 0,
+		 * in order to be computed by hardware NICs.
+		 */
+		if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
+			ipv4_hdr = rte_pktmbuf_mtod_offset(m,
+					struct rte_ipv4_hdr *, m->outer_l2_len);
+			ipv4_hdr->hdr_checksum = 0;
+		}
+	}

 	/*
 	 * Check if headers are fragmented.
--
2.17.1