datapath-windows: Updated OvsTcpSegmentNBL to handle IP fragments.

With this patch, OvsTcpSegmentNBL not only supports fragmenting NBL
to TCP segments but also Ipv4 fragments.

To reflect the new changes, renamed function name from OvsTcpSegmentNBL
to OvsFragmentNBL and created a wrapper for OvsTcpSegmentNBL.

Signed-off-by: Anand Kumar <kumaranand@vmware.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>

1 files changed, 150 insertions, 21 deletions

diff --git a/datapath-windows/ovsext/BufferMgmt.c b/datapath-windows/ovsext/BufferMgmt.c
index d99052de4..5048ada0f 100644
--- a/datapath-windows/ovsext/BufferMgmt.c
+++ b/datapath-windows/ovsext/BufferMgmt.c
@@ -1084,6 +1084,31 @@ nblcopy_error:
     return NULL;
 }
 
+NDIS_STATUS
+GetIpHeaderInfo(PNET_BUFFER_LIST curNbl,
+                UINT32 *hdrSize)
+{
+    CHAR *ethBuf[sizeof(EthHdr)];
+    EthHdr *eth;
+    IPHdr *ipHdr;
+    PNET_BUFFER curNb;
+
+    curNb = NET_BUFFER_LIST_FIRST_NB(curNbl);
+    ASSERT(NET_BUFFER_NEXT_NB(curNb) == NULL);
+
+    eth = (EthHdr *)NdisGetDataBuffer(curNb, ETH_HEADER_LENGTH,
+                                      (PVOID)&ethBuf, 1, 0);
+    if (eth == NULL) {
+        return NDIS_STATUS_INVALID_PACKET;
+    }
+    ipHdr = (IPHdr *)((PCHAR)eth + ETH_HEADER_LENGTH);
+    if (ipHdr == NULL) {
+        return NDIS_STATUS_INVALID_PACKET;
+    }
+    *hdrSize = (UINT32)(ETH_HEADER_LENGTH + (ipHdr->ihl * 4));
+    return NDIS_STATUS_SUCCESS;
+}
+
 /*
  * --------------------------------------------------------------------------
  * GetSegmentHeaderInfo
@@ -1110,6 +1135,62 @@ GetSegmentHeaderInfo(PNET_BUFFER_LIST nbl,
     return NDIS_STATUS_SUCCESS;
 }
 
+/*
+ * --------------------------------------------------------------------------
+ * FixFragmentHeader
+ *
+ *    Fix IP length, Offset, IP checksum.
+ *    XXX - Support IpV6 Fragments
+ * --------------------------------------------------------------------------
+ */
+static NDIS_STATUS
+FixFragmentHeader(PNET_BUFFER nb, UINT16 fragmentSize,
+                  BOOLEAN lastPacket, UINT16 offset)
+{
+    EthHdr *dstEth = NULL;
+    PMDL mdl = NULL;
+    PUINT8 bufferStart = NULL;
+
+    mdl = NET_BUFFER_FIRST_MDL(nb);
+
+    bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(mdl, LowPagePriority);
+    if (!bufferStart) {
+        return NDIS_STATUS_RESOURCES;
+    }
+    dstEth = (EthHdr *)(bufferStart + NET_BUFFER_CURRENT_MDL_OFFSET(nb));
+
+    switch (dstEth->Type) {
+    case ETH_TYPE_IPV4_NBO:
+    {
+        IPHdr *dstIP = NULL;
+        ASSERT((INT)MmGetMdlByteCount(mdl) - NET_BUFFER_CURRENT_MDL_OFFSET(nb)
+            >= sizeof(EthHdr) + sizeof(IPHdr));
+
+        dstIP = (IPHdr *)((PCHAR)dstEth + sizeof(*dstEth));
+        ASSERT((INT)MmGetMdlByteCount(mdl) - NET_BUFFER_CURRENT_MDL_OFFSET(nb)
+            >= sizeof(EthHdr) + dstIP->ihl * 4);
+        dstIP->tot_len = htons(fragmentSize + dstIP->ihl * 4);
+        if (lastPacket) {
+            dstIP->frag_off = htons(offset & IP_OFFSET);
+        } else {
+            dstIP->frag_off = htons((offset & IP_OFFSET) | IP_MF);
+        }
+
+        dstIP->check = 0;
+        dstIP->check = IPChecksum((UINT8 *)dstIP, dstIP->ihl * 4, 0);
+        break;
+    }
+    case ETH_TYPE_IPV6_NBO:
+    {
+        return NDIS_STATUS_NOT_SUPPORTED;
+    }
+    default:
+        OVS_LOG_ERROR("Invalid eth type: %d\n", dstEth->Type);
+        ASSERT(! "Invalid eth type");
+    }
+
+    return STATUS_SUCCESS;
+}
 
 /*
  * --------------------------------------------------------------------------
@@ -1217,12 +1298,29 @@ FixSegmentHeader(PNET_BUFFER nb, UINT16 segmentSize, UINT32 seqNumber,
 
     return STATUS_SUCCESS;
 }
+ /*
+  * --------------------------------------------------------------------------
+ * OvsTcpSegmentNBL --
+ *    Wrapper function to Fragment a given NBL based on MSS
+ * --------------------------------------------------------------------------
+ */
+PNET_BUFFER_LIST
+OvsTcpSegmentNBL(PVOID ovsContext,
+                 PNET_BUFFER_LIST nbl,
+                 POVS_PACKET_HDR_INFO hdrInfo,
+                 UINT32 mss,
+                 UINT32 headRoom,
+                 BOOLEAN isIpFragment)
+{
+    return OvsFragmentNBL(ovsContext, nbl, hdrInfo, mss, headRoom, isIpFragment);
+}
+
 
 /*
  * --------------------------------------------------------------------------
- * OvsTcpSegmentNBL --
+ * OvsFragmentNBL --
  *
- *    Segment TCP payload, and prepend each segment with ether/IP/TCP header.
+ *    Fragment NBL payload, and prepend each segment with Ether/IP/TCP header.
  *    Leave headRoom for additional encap.
  *
  *    Please note,
@@ -1235,24 +1333,25 @@ FixSegmentHeader(PNET_BUFFER nb, UINT16 segmentSize, UINT32 seqNumber,
  * --------------------------------------------------------------------------
  */
 PNET_BUFFER_LIST
-OvsTcpSegmentNBL(PVOID ovsContext,
-                 PNET_BUFFER_LIST nbl,
-                 POVS_PACKET_HDR_INFO hdrInfo,
-                 UINT32 mss,
-                 UINT32 headRoom)
+OvsFragmentNBL(PVOID ovsContext,
+               PNET_BUFFER_LIST nbl,
+               POVS_PACKET_HDR_INFO hdrInfo,
+               UINT32 fragmentSize,
+               UINT32 headRoom,
+               BOOLEAN isIpFragment)
 {
     POVS_SWITCH_CONTEXT context = (POVS_SWITCH_CONTEXT)ovsContext;
 #ifdef DBG
     POVS_NBL_POOL ovsPool = &context->ovsPool;
 #endif
     POVS_BUFFER_CONTEXT dstCtx, srcCtx;
-    UINT32 size, hdrSize, seqNumber;
+    UINT32 size, hdrSize, nblSize, seqNumber = 0;
     PNET_BUFFER_LIST newNbl;
     PNET_BUFFER nb, newNb;
     NDIS_STATUS status;
     UINT16 segmentSize;
     ULONG copiedSize;
-    UINT16 packetCounter = 0;
+    UINT16 offset = 0, packetCounter = 0;
 
     srcCtx = (POVS_BUFFER_CONTEXT)NET_BUFFER_LIST_CONTEXT_DATA_START(nbl);
     if (srcCtx == NULL || srcCtx->magic != OVS_CTX_MAGIC) {
@@ -1264,18 +1363,28 @@ OvsTcpSegmentNBL(PVOID ovsContext,
     nb = NET_BUFFER_LIST_FIRST_NB(nbl);
     ASSERT(NET_BUFFER_NEXT_NB(nb) == NULL);
 
-    /* Figure out the segment header size */
-    status = GetSegmentHeaderInfo(nbl, hdrInfo, &hdrSize, &seqNumber);
+    /* Figure out the header size */
+    if (isIpFragment) {
+        status = GetIpHeaderInfo(nbl, &hdrSize);
+    } else {
+        status = GetSegmentHeaderInfo(nbl, hdrInfo, &hdrSize, &seqNumber);
+    }
     if (status != NDIS_STATUS_SUCCESS) {
         OVS_LOG_INFO("Cannot parse NBL header");
         return NULL;
     }
-
+    /* Get the NBL size. */
+    if (isIpFragment) {
+        nblSize = fragmentSize - hdrSize;
+    } else {
+        nblSize = fragmentSize;
+    }
     size = NET_BUFFER_DATA_LENGTH(nb) - hdrSize;
 
     /* XXX add to ovsPool counters? */
-    newNbl = NdisAllocateFragmentNetBufferList(nbl, NULL,
-            NULL, hdrSize, mss, hdrSize + headRoom , 0, 0);
+    newNbl = NdisAllocateFragmentNetBufferList(nbl, NULL, NULL, hdrSize,
+                                               nblSize, hdrSize + headRoom ,
+                                               0, 0);
     if (newNbl == NULL) {
         return NULL;
     }
@@ -1283,7 +1392,7 @@ OvsTcpSegmentNBL(PVOID ovsContext,
     /* Now deal with TCP payload */
     for (newNb = NET_BUFFER_LIST_FIRST_NB(newNbl); newNb != NULL;
             newNb = NET_BUFFER_NEXT_NB(newNb)) {
-        segmentSize = (size > mss ? mss : size) & 0xffff;
+        segmentSize = (size > nblSize ? nblSize : size) & 0xffff;
         if (headRoom) {
             NdisAdvanceNetBufferDataStart(newNb, headRoom, FALSE, NULL);
         }
@@ -1295,17 +1404,27 @@ OvsTcpSegmentNBL(PVOID ovsContext,
             goto nblcopy_error;
         }
 
-        status = FixSegmentHeader(newNb, segmentSize, seqNumber,
-                                  NET_BUFFER_NEXT_NB(newNb) == NULL,
-                                  packetCounter);
+        if (isIpFragment) {
+            status = FixFragmentHeader(newNb, segmentSize,
+                                       NET_BUFFER_NEXT_NB(newNb) == NULL,
+                                       offset);
+        } else {
+            status = FixSegmentHeader(newNb, segmentSize, seqNumber,
+                                      NET_BUFFER_NEXT_NB(newNb) == NULL,
+                                      packetCounter);
+        }
+
         if (status != NDIS_STATUS_SUCCESS) {
             goto nblcopy_error;
         }
 
-
         /* Move on to the next segment */
+        if (isIpFragment) {
+            offset += (segmentSize) / 8;
+        } else {
+            seqNumber += segmentSize;
+        }
         size -= segmentSize;
-        seqNumber += segmentSize;
         packetCounter++;
     }
 
@@ -1319,6 +1438,15 @@ OvsTcpSegmentNBL(PVOID ovsContext,
         goto nbl_context_error;
     }
 
+    if (isIpFragment) {
+    /*Copy with Flag - NDIS_SWITCH_COPY_NBL_INFO_FLAGS_PRESERVE_DESTINATIONS.*/
+        status = context->NdisSwitchHandlers.
+            CopyNetBufferListInfo(context->ovsPool.ndisContext, newNbl, nbl, 1);
+
+        if (status != NDIS_STATUS_SUCCESS) {
+            goto nbl_context_error;
+        }
+    }
     newNbl->ParentNetBufferList = nbl;
 
     /* Remember it's a fragment NBL so we can free it properly */
@@ -1329,6 +1457,7 @@ OvsTcpSegmentNBL(PVOID ovsContext,
     dstCtx->refCount = 1;
     dstCtx->magic = OVS_CTX_MAGIC;
     dstCtx->dataOffsetDelta = hdrSize + headRoom;
+    dstCtx->mru = 0;
 
     InterlockedIncrement((LONG volatile *)&srcCtx->refCount);
 #ifdef DBG
@@ -1340,7 +1469,7 @@ OvsTcpSegmentNBL(PVOID ovsContext,
     OvsDumpNetBufferList(newNbl);
     OvsDumpForwardingDetails(newNbl);
 #endif
-    OVS_LOG_TRACE("Segment nbl %p to newNbl: %p", nbl, newNbl);
+    OVS_LOG_TRACE("Fragment nbl %p to newNbl: %p", nbl, newNbl);
     return newNbl;
 
 nbl_context_error: