datapath-windows: Fragment NBL based on MRU size

This patch adds support for Fragmenting NBL based on the MRU value.
MRU value is updated only for Ipv4 fragments, if it is non zero, then
fragment the NBL and send out the new NBL to the vnic.

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, 50 insertions, 1 deletions

diff --git a/datapath-windows/ovsext/Actions.c b/datapath-windows/ovsext/Actions.c
index b5c13c75b..e2eae9a88 100644
--- a/datapath-windows/ovsext/Actions.c
+++ b/datapath-windows/ovsext/Actions.c
@@ -34,6 +34,7 @@
 #include "Vport.h"
 #include "Vxlan.h"
 #include "Geneve.h"
+#include "IpFragment.h"
 
 #ifdef OVS_DBG_MOD
 #undef OVS_DBG_MOD
@@ -144,6 +145,36 @@ OvsInitForwardingCtx(OvsForwardingContext *ovsFwdCtx,
 
 /*
  * --------------------------------------------------------------------------
+ * OvsDoFragmentNbl --
+ *     Utility function to Fragment nbl based on mru.
+ * --------------------------------------------------------------------------
+ */
+static __inline VOID
+OvsDoFragmentNbl(OvsForwardingContext *ovsFwdCtx, UINT16 mru)
+{
+    PNET_BUFFER_LIST fragNbl = NULL;
+    fragNbl = OvsFragmentNBL(ovsFwdCtx->switchContext,
+                             ovsFwdCtx->curNbl,
+                             &(ovsFwdCtx->layers),
+                             mru, 0, TRUE);
+
+   if (fragNbl != NULL) {
+        OvsCompleteNBL(ovsFwdCtx->switchContext, ovsFwdCtx->curNbl, TRUE);
+        OvsInitForwardingCtx(ovsFwdCtx,
+                            ovsFwdCtx->switchContext,
+                             fragNbl,
+                             ovsFwdCtx->srcVportNo,
+                             ovsFwdCtx->sendFlags,
+                             NET_BUFFER_LIST_SWITCH_FORWARDING_DETAIL(fragNbl),
+                             ovsFwdCtx->completionList,
+                             &ovsFwdCtx->layers, FALSE);
+    } else {
+        OVS_LOG_INFO("Fragment NBL failed for MRU = %u", mru);
+    }
+}
+
+/*
+ * --------------------------------------------------------------------------
  * OvsDetectTunnelRxPkt --
  *     Utility function for an RX packet to detect its tunnel type.
  *
@@ -604,6 +635,7 @@ OvsTunnelPortTx(OvsForwardingContext *ovsFwdCtx)
     UINT32 srcVportNo;
     NDIS_SWITCH_NIC_INDEX srcNicIndex;
     NDIS_SWITCH_PORT_ID srcPortId;
+    POVS_BUFFER_CONTEXT ctx;
 
     /*
      * Setup the source port to be the internal port to as to facilitate the
@@ -617,6 +649,10 @@ OvsTunnelPortTx(OvsForwardingContext *ovsFwdCtx)
         return NDIS_STATUS_FAILURE;
     }
 
+    ctx = (POVS_BUFFER_CONTEXT)NET_BUFFER_LIST_CONTEXT_DATA_START(ovsFwdCtx->curNbl);
+    if (ctx->mru != 0) {
+        OvsDoFragmentNbl(ovsFwdCtx, ctx->mru);
+    }
     OVS_FWD_INFO switchFwdInfo = { 0 };
     /* Apply the encapsulation. The encapsulation will not consume the NBL. */
     switch(ovsFwdCtx->tunnelTxNic->ovsType) {
@@ -807,6 +843,7 @@ OvsOutputForwardingCtx(OvsForwardingContext *ovsFwdCtx)
     NDIS_STATUS status = STATUS_SUCCESS;
     POVS_SWITCH_CONTEXT switchContext = ovsFwdCtx->switchContext;
     PCWSTR dropReason;
+    POVS_BUFFER_CONTEXT ctx;
 
     /*
      * Handle the case where the some of the destination ports are tunneled
@@ -829,8 +866,12 @@ OvsOutputForwardingCtx(OvsForwardingContext *ovsFwdCtx)
          * before doing encapsulation.
          */
         if (ovsFwdCtx->tunnelTxNic != NULL || ovsFwdCtx->tunnelRxNic != NULL) {
+            POVS_BUFFER_CONTEXT oldCtx, newCtx;
             nb = NET_BUFFER_LIST_FIRST_NB(ovsFwdCtx->curNbl);
-            newNbl = OvsPartialCopyNBL(ovsFwdCtx->switchContext, ovsFwdCtx->curNbl,
+            oldCtx = (POVS_BUFFER_CONTEXT)
+                NET_BUFFER_LIST_CONTEXT_DATA_START(ovsFwdCtx->curNbl);
+            newNbl = OvsPartialCopyNBL(ovsFwdCtx->switchContext,
+                                       ovsFwdCtx->curNbl,
                                        0, 0, TRUE /*copy NBL info*/);
             if (newNbl == NULL) {
                 status = NDIS_STATUS_RESOURCES;
@@ -838,6 +879,9 @@ OvsOutputForwardingCtx(OvsForwardingContext *ovsFwdCtx)
                 dropReason = L"Dropped due to failure to create NBL copy.";
                 goto dropit;
             }
+            newCtx = (POVS_BUFFER_CONTEXT)
+                NET_BUFFER_LIST_CONTEXT_DATA_START(newNbl);
+            newCtx->mru = oldCtx->mru;
         }
 
         /* It does not seem like we'll get here unless 'portsToUpdate' > 0. */
@@ -852,6 +896,11 @@ OvsOutputForwardingCtx(OvsForwardingContext *ovsFwdCtx)
             goto dropit;
         }
 
+        ctx = (POVS_BUFFER_CONTEXT)NET_BUFFER_LIST_CONTEXT_DATA_START(ovsFwdCtx->curNbl);
+        if (ctx->mru != 0) {
+            OvsDoFragmentNbl(ovsFwdCtx, ctx->mru);
+        }
+
         OvsSendNBLIngress(ovsFwdCtx->switchContext, ovsFwdCtx->curNbl,
                           ovsFwdCtx->sendFlags);
         /* End this pipeline by resetting the corresponding context. */