datapath-windows: Add software checksums for nbl which contain multiple nb

Until now we only needed to compute software checksums on net buffer lists
containing a single net buffer.

This patch allows the software checksums to be applied on a net buffer list
with multiple net buffers. The hard assumption for this, is the net buffers are
part of the same connection. The position of the offsets is pointed by the
layers parameter.

This will be useful for introducing support ip fragments in conntrack.

Signed-off-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Acked-by: Anand Kumar <kumaranand@vmware.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>

1 files changed, 54 insertions, 51 deletions

diff --git a/datapath-windows/ovsext/Offload.c b/datapath-windows/ovsext/Offload.c
index f3ab0e169..65d3b6744 100644
--- a/datapath-windows/ovsext/Offload.c
+++ b/datapath-windows/ovsext/Offload.c
@@ -647,7 +647,9 @@ OvsCalculateUDPChecksum(PNET_BUFFER_LIST curNbl,
  * OvsApplySWChecksumOnNB --
  *
  * This function calculates and sets the required software offloads given by
- * csumInfo for a given NBL(nbl) with a single NB.
+ * csumInfo for a given NBL(nbl). If the given net buffer list 'nbl'
+ * has multiple net buffers, we assume that they are part of the same
+ * connection with the same offsets defined in 'layers'.
  *
  */
 NDIS_STATUS
@@ -661,60 +663,61 @@ OvsApplySWChecksumOnNB(POVS_PACKET_HDR_INFO layers,
     UINT32 packetLength = 0;
     ASSERT(nbl != NULL);
 
-    curNb = NET_BUFFER_LIST_FIRST_NB(nbl);
-    ASSERT(curNb->Next == NULL);
-    packetLength = NET_BUFFER_DATA_LENGTH(curNb);
-    curMdl = NET_BUFFER_CURRENT_MDL(curNb);
-    bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
-                                                       LowPagePriority);
-    if (!bufferStart) {
-        return NDIS_STATUS_RESOURCES;
-    }
+    for (curNb = NET_BUFFER_LIST_FIRST_NB(nbl); curNb != NULL;
+         curNb = curNb->Next) {
+        packetLength = NET_BUFFER_DATA_LENGTH(curNb);
+        curMdl = NET_BUFFER_CURRENT_MDL(curNb);
+        bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
+                                                           LowPagePriority);
+        if (!bufferStart) {
+            return NDIS_STATUS_RESOURCES;
+        }
 
-    bufferStart += NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
+        bufferStart += NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
 
-    if (layers->isIPv4) {
-        IPHdr *ip = (IPHdr *)(bufferStart + layers->l3Offset);
+        if (layers->isIPv4) {
+            IPHdr *ip = (IPHdr *)(bufferStart + layers->l3Offset);
 
-        if (csumInfo->Transmit.IpHeaderChecksum) {
-            ip->check = 0;
-            ip->check = IPChecksum((UINT8 *)ip, 4 * ip->ihl, 0);
-        }
+            if (csumInfo->Transmit.IpHeaderChecksum) {
+                ip->check = 0;
+                ip->check = IPChecksum((UINT8 *)ip, 4 * ip->ihl, 0);
+            }
 
-        if (layers->isTcp && csumInfo->Transmit.TcpChecksum) {
-            UINT16 csumLength = (UINT16)(packetLength - layers->l4Offset);
-            TCPHdr *tcp = (TCPHdr *)(bufferStart + layers->l4Offset);
-            tcp->check = IPPseudoChecksum(&ip->saddr, &ip->daddr,
-                                          IPPROTO_TCP, csumLength);
-            tcp->check = CalculateChecksumNB(curNb, csumLength,
-                                             (UINT32)(layers->l4Offset));
-        } else if (layers->isUdp && csumInfo->Transmit.UdpChecksum) {
-            UINT16 csumLength = (UINT16)(packetLength - layers->l4Offset);
-            UDPHdr *udp = (UDPHdr *)((PCHAR)ip + sizeof *ip);
-            udp->check = IPPseudoChecksum(&ip->saddr, &ip->daddr,
-                                          IPPROTO_UDP, csumLength);
-            udp->check = CalculateChecksumNB(curNb, csumLength,
-                                             (UINT32)(layers->l4Offset));
-        }
-    } else if (layers->isIPv6) {
-        IPv6Hdr *ip = (IPv6Hdr *)(bufferStart + layers->l3Offset);
-
-        if (layers->isTcp && csumInfo->Transmit.TcpChecksum) {
-            UINT16 csumLength = (UINT16)(packetLength - layers->l4Offset);
-            TCPHdr *tcp = (TCPHdr *)(bufferStart + layers->l4Offset);
-            tcp->check = IPv6PseudoChecksum((UINT32 *) &ip->saddr,
-                                            (UINT32 *) &ip->daddr,
-                                            IPPROTO_TCP, csumLength);
-            tcp->check = CalculateChecksumNB(curNb, csumLength,
-                                             (UINT32)(layers->l4Offset));
-        } else if (layers->isUdp && csumInfo->Transmit.UdpChecksum) {
-            UINT16 csumLength = (UINT16)(packetLength - layers->l4Offset);
-            UDPHdr *udp = (UDPHdr *)((PCHAR)ip + sizeof *ip);
-            udp->check = IPv6PseudoChecksum((UINT32 *) &ip->saddr,
-                                            (UINT32 *) &ip->daddr,
-                                            IPPROTO_UDP, csumLength);
-            udp->check = CalculateChecksumNB(curNb, csumLength,
-                                             (UINT32)(layers->l4Offset));
+            if (layers->isTcp && csumInfo->Transmit.TcpChecksum) {
+                UINT16 csumLength = (UINT16)(packetLength - layers->l4Offset);
+                TCPHdr *tcp = (TCPHdr *)(bufferStart + layers->l4Offset);
+                tcp->check = IPPseudoChecksum(&ip->saddr, &ip->daddr,
+                                              IPPROTO_TCP, csumLength);
+                tcp->check = CalculateChecksumNB(curNb, csumLength,
+                                                 (UINT32)(layers->l4Offset));
+            } else if (layers->isUdp && csumInfo->Transmit.UdpChecksum) {
+                UINT16 csumLength = (UINT16)(packetLength - layers->l4Offset);
+                UDPHdr *udp = (UDPHdr *)((PCHAR)ip + sizeof *ip);
+                udp->check = IPPseudoChecksum(&ip->saddr, &ip->daddr,
+                                              IPPROTO_UDP, csumLength);
+                udp->check = CalculateChecksumNB(curNb, csumLength,
+                                                 (UINT32)(layers->l4Offset));
+            }
+        } else if (layers->isIPv6) {
+            IPv6Hdr *ip = (IPv6Hdr *)(bufferStart + layers->l3Offset);
+
+            if (layers->isTcp && csumInfo->Transmit.TcpChecksum) {
+                UINT16 csumLength = (UINT16)(packetLength - layers->l4Offset);
+                TCPHdr *tcp = (TCPHdr *)(bufferStart + layers->l4Offset);
+                tcp->check = IPv6PseudoChecksum((UINT32 *) &ip->saddr,
+                                                (UINT32 *) &ip->daddr,
+                                                IPPROTO_TCP, csumLength);
+                tcp->check = CalculateChecksumNB(curNb, csumLength,
+                                                 (UINT32)(layers->l4Offset));
+            } else if (layers->isUdp && csumInfo->Transmit.UdpChecksum) {
+                UINT16 csumLength = (UINT16)(packetLength - layers->l4Offset);
+                UDPHdr *udp = (UDPHdr *)((PCHAR)ip + sizeof *ip);
+                udp->check = IPv6PseudoChecksum((UINT32 *) &ip->saddr,
+                                                (UINT32 *) &ip->daddr,
+                                                IPPROTO_UDP, csumLength);
+                udp->check = CalculateChecksumNB(curNb, csumLength,
+                                                 (UINT32)(layers->l4Offset));
+            }
         }
     }