From 7468ec78853e4c82865776c6c003a64b7b8b2a5e Mon Sep 17 00:00:00 2001
From: Anand Kumar <kumaranand@vmware.com>
Date: Fri, 15 Sep 2017 15:04:49 -0700
Subject: datapath-windows: Remove the workaround in NAT for TCP checksum

When checksum offload is enabled, compute checksum using the
TCP pseudo header.

Signed-off-by: Anand Kumar <kumaranand@vmware.com>
Acked-by: Alin Gabriel Serdean <aserdean@ovn.org>
Signed-off-by: Alin Gabriel Serdean <aserdean@ovn.org>
---
 datapath-windows/ovsext/Actions.c | 60 +++++++--------------------------------
 1 file changed, 11 insertions(+), 49 deletions(-)

(limited to 'datapath-windows')

diff --git a/datapath-windows/ovsext/Actions.c b/datapath-windows/ovsext/Actions.c
index 41d1c7b1b..0af4a660d 100644
--- a/datapath-windows/ovsext/Actions.c
+++ b/datapath-windows/ovsext/Actions.c
@@ -1528,6 +1528,11 @@ OvsUpdateAddressAndPort(OvsForwardingContext *ovsFwdCtx,
                         ((BOOLEAN)csumInfo.Receive.UdpChecksumSucceeded ||
                          (BOOLEAN)csumInfo.Receive.UdpChecksumFailed);
         }
+        if (l4Offload) {
+            *checkField = IPPseudoChecksum(&newAddr, &ipHdr->daddr,
+                tcpHdr ? IPPROTO_TCP : IPPROTO_UDP,
+                ntohs(ipHdr->tot_len) - ipHdr->ihl * 4);
+        }
     } else {
         addrField = &ipHdr->daddr;
         if (tcpHdr) {
@@ -1538,19 +1543,13 @@ OvsUpdateAddressAndPort(OvsForwardingContext *ovsFwdCtx,
             checkField = &udpHdr->check;
         }
     }
+
     if (*addrField != newAddr) {
         UINT32 oldAddr = *addrField;
-        if (checkField && *checkField != 0) {
-            if (l4Offload) {
-                /* Recompute IP pseudo checksum */
-                *checkField = ~(*checkField);
-                *checkField = ChecksumUpdate32(*checkField, oldAddr,
-                                               newAddr);
-                *checkField = ~(*checkField);
-            } else {
-                *checkField = ChecksumUpdate32(*checkField, oldAddr,
-                                               newAddr);
-            }
+        if (checkField && *checkField != 0 && !l4Offload) {
+            /* Recompute total checksum. */
+            *checkField = ChecksumUpdate32(*checkField, oldAddr,
+                                            newAddr);
         }
         if (ipHdr->check != 0) {
             ipHdr->check = ChecksumUpdate32(ipHdr->check, oldAddr,
@@ -1561,49 +1560,12 @@ OvsUpdateAddressAndPort(OvsForwardingContext *ovsFwdCtx,
 
     if (portField && *portField != newPort) {
         if (checkField && !l4Offload) {
+            /* Recompute total checksum. */
             *checkField = ChecksumUpdate16(*checkField, *portField,
                                            newPort);
         }
         *portField = newPort;
     }
-    PNET_BUFFER_LIST curNbl = ovsFwdCtx->curNbl;
-    PNET_BUFFER_LIST newNbl = NULL;
-    if (layers->isTcp) {
-        UINT32 mss = OVSGetTcpMSS(curNbl);
-        if (mss) {
-            OVS_LOG_TRACE("l4Offset %d", layers->l4Offset);
-            newNbl = OvsTcpSegmentNBL(ovsFwdCtx->switchContext, curNbl, layers,
-                                      mss, 0, FALSE);
-            if (newNbl == NULL) {
-                OVS_LOG_ERROR("Unable to segment NBL");
-                return NDIS_STATUS_FAILURE;
-            }
-            /* Clear out LSO flags after this point */
-            NET_BUFFER_LIST_INFO(newNbl, TcpLargeSendNetBufferListInfo) = 0;
-        }
-    }
-    /* If we didn't split the packet above, make a copy now */
-    if (newNbl == NULL) {
-        csumInfo.Value = NET_BUFFER_LIST_INFO(curNbl,
-                                              TcpIpChecksumNetBufferListInfo);
-        OvsApplySWChecksumOnNB(layers, curNbl, &csumInfo);
-    }
-
-    if (newNbl) {
-        curNbl = newNbl;
-        OvsCompleteNBLForwardingCtx(ovsFwdCtx,
-                                    L"Complete after cloning NBL for encapsulation");
-        OvsInitForwardingCtx(ovsFwdCtx, ovsFwdCtx->switchContext,
-                             newNbl, ovsFwdCtx->srcVportNo, 0,
-                             NET_BUFFER_LIST_SWITCH_FORWARDING_DETAIL(newNbl),
-                             ovsFwdCtx->completionList,
-                             &ovsFwdCtx->layers, FALSE);
-        ovsFwdCtx->curNbl = newNbl;
-    }
-
-    NET_BUFFER_LIST_INFO(curNbl,
-                         TcpIpChecksumNetBufferListInfo) = 0;
-
     return NDIS_STATUS_SUCCESS;
 }
 
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