From: Steven Luong <sluong@cisco.com>
Date: Mon, 27 Jan 2020 18:37:56 +0000 (-0800)
Subject: interface: Add missing ip4 udp->checksum = 0 prior to computing checksum
X-Git-Tag: v19.08.3~178
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=refs%2Fchanges%2F04%2F28304%2F1;p=vpp.git

interface: Add missing ip4 udp->checksum = 0 prior to computing checksum

For ip4 tcp, ip6 tcp, and ip6 udp packet, we set checksum = 0 prior to
computing the checksum. We missed ip4 udp case. This oversight requires all
clients to set udp->checksum = 0 if ip4 udp checksum offload is needed.

Type: fix

Signed-off-by: Steven Luong <sluong@cisco.com>
Change-Id: Ic608811e82099f3bec469e123671e9b281f38d76
(cherry picked from commit 03328ec8bb86b93fa70bb6b2a9b37c40e686a1f7)
---

diff --git a/src/vnet/interface_output.c b/src/vnet/interface_output.c
index ec92c38edc6..549ed91676f 100644
--- a/src/vnet/interface_output.c
+++ b/src/vnet/interface_output.c
@@ -204,7 +204,10 @@ calc_checksums (vlib_main_t * vm, vlib_buffer_t * b)
 	  th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ip4);
 	}
       else if (b->flags & VNET_BUFFER_F_OFFLOAD_UDP_CKSUM)
-	uh->checksum = ip4_tcp_udp_compute_checksum (vm, b, ip4);
+	{
+	  uh->checksum = 0;
+	  uh->checksum = ip4_tcp_udp_compute_checksum (vm, b, ip4);
+	}
     }
   else if (is_ip6)
     {