commit 9d7570ccde4ded1c5feea097b10272870bfc81da
author Andrej Kozemcak <andrej.kozemcak@pantheon.tech> Mon Jan 07 08:39:22 2019 +0100
committer Florin Coras <florin.coras@gmail.com> Mon Jan 07 16:43:37 2019 +0000
tree 8b1134069f2aff34c7be5bb0810769cdb94333b8
parent 7baeb71f92826ee6ef02ab2c3d16484bb64d9301

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>

src/vnet/interface_output.c

diff --git a/src/vnet/interface_output.c b/src/vnet/interface_output.c
index 34f0a97..ba69d36 100644
--- a/src/vnet/interface_output.c
+++ b/src/vnet/interface_output.c
@@ -181,7 +181,10 @@
       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);
     }