From: Andrej Kozemcak <andrej.kozemcak@pantheon.tech>
Date: Mon, 7 Jan 2019 07:39:22 +0000 (+0100)
Subject: Fix TCP checksum.
X-Git-Tag: v19.04-rc0~40
X-Git-Url: https://gerrit.fd.io/r/gitweb?p=vpp.git;a=commitdiff_plain;h=9d7570ccde4ded1c5feea097b10272870bfc81da

Fix TCP checksum.

Set TCP checksum to zero, before calculate the TCP checksum.

Change-Id: Id96743334481804b8ebb74afef2f1dbfed29e0cb
Signed-off-by: Andrej Kozemcak <andrej.kozemcak@pantheon.tech>
---

diff --git a/src/vnet/interface_output.c b/src/vnet/interface_output.c
index 34f0a977131..ba69d36b6c4 100644
--- a/src/vnet/interface_output.c
+++ b/src/vnet/interface_output.c
@@ -181,7 +181,10 @@ calc_checksums (vlib_main_t * vm, vlib_buffer_t * b)
       if (b->flags & VNET_BUFFER_F_OFFLOAD_IP_CKSUM)
 	ip4->checksum = ip4_header_checksum (ip4);
       if (b->flags & VNET_BUFFER_F_OFFLOAD_TCP_CKSUM)
-	th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ip4);
+	{
+	  th->checksum = 0;
+	  th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ip4);
+	}
       if (b->flags & VNET_BUFFER_F_OFFLOAD_UDP_CKSUM)
 	uh->checksum = ip4_tcp_udp_compute_checksum (vm, b, ip4);
     }