datapath-windows: Support for OVS_KEY_ATTR_MPLS attribute

This patch adds OVS_KEY_ATTR_MPLS to the OVS flow mechanism.

Tested using ping.
Tested using iperf (TCP and UDP).
Tested using DriverVerifier.

Signed-off-by: Sorin Vinturis <svinturis@cloudbasesolutions.com>
Acked-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>

11 files changed, 371 insertions, 31 deletions

diff --git a/datapath-windows/automake.mk b/datapath-windows/automake.mk
index 7f12d92d7..fd2221850 100644
--- a/datapath-windows/automake.mk
+++ b/datapath-windows/automake.mk
@@ -31,6 +31,7 @@ EXTRA_DIST += \
 	datapath-windows/ovsext/IpHelper.h \
 	datapath-windows/ovsext/Jhash.c \
 	datapath-windows/ovsext/Jhash.h \
+	datapath-windows/ovsext/Mpls.h \
 	datapath-windows/ovsext/NetProto.h \
 	datapath-windows/ovsext/Netlink/Netlink.c \
 	datapath-windows/ovsext/Netlink/Netlink.h \
diff --git a/datapath-windows/ovsext/Actions.c b/datapath-windows/ovsext/Actions.c
index 650658476..8e41b7455 100644
--- a/datapath-windows/ovsext/Actions.c
+++ b/datapath-windows/ovsext/Actions.c
@@ -20,6 +20,7 @@
 #include "Event.h"
 #include "Flow.h"
 #include "Gre.h"
+#include "Mpls.h"
 #include "NetProto.h"
 #include "PacketIO.h"
 #include "Stt.h"
@@ -1031,28 +1032,29 @@ OvsOutputBeforeSetAction(OvsForwardingContext *ovsFwdCtx)
 
 /*
  * --------------------------------------------------------------------------
- * OvsPopVlanInPktBuf --
- *     Function to pop a VLAN tag when the tag is in the packet buffer.
+ * OvsPopFieldInPacketBuf --
+ *     Function to pop a specified field of length 'shiftLength' located at
+ *     'shiftOffset' from the ethernet header. The data on the left of the
+ *     'shiftOffset' is right shifted.
+ *
+ *     Returns a pointer to the new start in 'bufferData'.
  * --------------------------------------------------------------------------
  */
 static __inline NDIS_STATUS
-OvsPopVlanInPktBuf(OvsForwardingContext *ovsFwdCtx)
+OvsPopFieldInPacketBuf(OvsForwardingContext *ovsFwdCtx,
+                       UINT32 shiftOffset,
+                       UINT32 shiftLength,
+                       PUINT8 *bufferData)
 {
     PNET_BUFFER curNb;
     PMDL curMdl;
     PUINT8 bufferStart;
-    ULONG dataLength = sizeof (DL_EUI48) + sizeof (DL_EUI48);
     UINT32 packetLen, mdlLen;
     PNET_BUFFER_LIST newNbl;
     NDIS_STATUS status;
+    PUINT8 tempBuffer[ETH_HEADER_LENGTH];
 
-    /*
-     * Declare a dummy vlanTag structure since we need to compute the size
-     * of shiftLength. The NDIS one is a unionized structure.
-     */
-    NDIS_PACKET_8021Q_INFO vlanTag = {0};
-    ULONG shiftLength = sizeof (vlanTag.TagHeader);
-    PUINT8 tempBuffer[sizeof (DL_EUI48) + sizeof (DL_EUI48)];
+    ASSERT(shiftOffset > ETH_ADDR_LENGTH);
 
     newNbl = OvsPartialCopyNBL(ovsFwdCtx->switchContext, ovsFwdCtx->curNbl,
                                0, 0, TRUE /* copy NBL info */);
@@ -1064,8 +1066,8 @@ OvsPopVlanInPktBuf(OvsForwardingContext *ovsFwdCtx)
     /* Complete the original NBL and create a copy to modify. */
     OvsCompleteNBLForwardingCtx(ovsFwdCtx, L"OVS-Dropped due to copy");
 
-    status = OvsInitForwardingCtx(ovsFwdCtx, ovsFwdCtx->switchContext,
-                                  newNbl, ovsFwdCtx->srcVportNo, 0,
+    status = OvsInitForwardingCtx(ovsFwdCtx, ovsFwdCtx->switchContext, newNbl,
+                                  ovsFwdCtx->srcVportNo, 0,
                                   NET_BUFFER_LIST_SWITCH_FORWARDING_DETAIL(newNbl),
                                   NULL, &ovsFwdCtx->layers, FALSE);
     if (status != NDIS_STATUS_SUCCESS) {
@@ -1083,16 +1085,142 @@ OvsPopVlanInPktBuf(OvsForwardingContext *ovsFwdCtx)
         return NDIS_STATUS_RESOURCES;
     }
     mdlLen -= NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
-    /* Bail out if L2 + VLAN header is not contiguous in the first buffer. */
-    if (MIN(packetLen, mdlLen) < sizeof (EthHdr) + shiftLength) {
+    /* Bail out if L2 + shiftLength is not contiguous in the first buffer. */
+    if (MIN(packetLen, mdlLen) < sizeof(EthHdr) + shiftLength) {
         ASSERT(FALSE);
         return NDIS_STATUS_FAILURE;
     }
     bufferStart += NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
-    RtlCopyMemory(tempBuffer, bufferStart, dataLength);
-    RtlCopyMemory(bufferStart + shiftLength, tempBuffer, dataLength);
+    RtlCopyMemory(tempBuffer, bufferStart, shiftOffset);
+    RtlCopyMemory(bufferStart + shiftLength, tempBuffer, shiftOffset);
     NdisAdvanceNetBufferDataStart(curNb, shiftLength, FALSE, NULL);
 
+    if (bufferData) {
+        *bufferData = bufferStart + shiftLength;
+    }
+
+    return NDIS_STATUS_SUCCESS;
+}
+
+
+/*
+ * --------------------------------------------------------------------------
+ * OvsPopVlanInPktBuf --
+ *     Function to pop a VLAN tag when the tag is in the packet buffer.
+ * --------------------------------------------------------------------------
+ */
+static __inline NDIS_STATUS
+OvsPopVlanInPktBuf(OvsForwardingContext *ovsFwdCtx)
+{
+    /*
+     * Declare a dummy vlanTag structure since we need to compute the size
+     * of shiftLength. The NDIS one is a unionized structure.
+     */
+    NDIS_PACKET_8021Q_INFO vlanTag = {0};
+    UINT32 shiftLength = sizeof(vlanTag.TagHeader);
+    UINT32 shiftOffset = sizeof(DL_EUI48) + sizeof(DL_EUI48);
+
+    return OvsPopFieldInPacketBuf(ovsFwdCtx, shiftOffset, shiftLength, NULL);
+}
+
+
+/*
+ * --------------------------------------------------------------------------
+ * OvsActionMplsPop --
+ *     Function to pop the first MPLS label from the current packet.
+ * --------------------------------------------------------------------------
+ */
+static __inline NDIS_STATUS
+OvsActionMplsPop(OvsForwardingContext *ovsFwdCtx,
+                 ovs_be16 ethertype)
+{
+    NDIS_STATUS status = NDIS_STATUS_SUCCESS;
+    OVS_PACKET_HDR_INFO *layers = &ovsFwdCtx->layers;
+    EthHdr *ethHdr = NULL;
+
+    status = OvsPopFieldInPacketBuf(ovsFwdCtx, sizeof(*ethHdr),
+                                    MPLS_HLEN, (PUINT8*)&ethHdr);
+    if (status == NDIS_STATUS_SUCCESS) {
+        if (ethHdr && OvsEthertypeIsMpls(ethHdr->Type)) {
+            ethHdr->Type = ethertype;
+        }
+
+        layers->l3Offset -= MPLS_HLEN;
+        layers->l4Offset -= MPLS_HLEN;
+    }
+
+    return status;
+}
+
+
+/*
+ * --------------------------------------------------------------------------
+ * OvsActionMplsPush --
+ *     Function to push the MPLS label into the current packet.
+ * --------------------------------------------------------------------------
+ */
+static __inline NDIS_STATUS
+OvsActionMplsPush(OvsForwardingContext *ovsFwdCtx,
+                  const struct ovs_action_push_mpls *mpls)
+{
+    NDIS_STATUS status;
+    PNET_BUFFER curNb = NULL;
+    PMDL curMdl = NULL;
+    PUINT8 bufferStart = NULL;
+    OVS_PACKET_HDR_INFO *layers = &ovsFwdCtx->layers;
+    EthHdr *ethHdr = NULL;
+    MPLSHdr *mplsHdr = NULL;
+    UINT32 mdlLen = 0, curMdlOffset = 0;
+    PNET_BUFFER_LIST newNbl;
+
+    newNbl = OvsPartialCopyNBL(ovsFwdCtx->switchContext, ovsFwdCtx->curNbl,
+                               layers->l3Offset, MPLS_HLEN, TRUE);
+    if (!newNbl) {
+        ovsActionStats.noCopiedNbl++;
+        return NDIS_STATUS_RESOURCES;
+    }
+    OvsCompleteNBLForwardingCtx(ovsFwdCtx,
+                                L"Complete after partial copy.");
+
+    status = OvsInitForwardingCtx(ovsFwdCtx, ovsFwdCtx->switchContext,
+                                  newNbl, ovsFwdCtx->srcVportNo, 0,
+                                  NET_BUFFER_LIST_SWITCH_FORWARDING_DETAIL(newNbl),
+                                  NULL, &ovsFwdCtx->layers, FALSE);
+    if (status != NDIS_STATUS_SUCCESS) {
+        OvsCompleteNBLForwardingCtx(ovsFwdCtx,
+                                    L"OVS-Dropped due to resources");
+        return NDIS_STATUS_RESOURCES;
+    }
+
+    curNb = NET_BUFFER_LIST_FIRST_NB(ovsFwdCtx->curNbl);
+    ASSERT(curNb->Next == NULL);
+
+    status = NdisRetreatNetBufferDataStart(curNb, MPLS_HLEN, 0, NULL);
+    if (status != NDIS_STATUS_SUCCESS) {
+        return status;
+    }
+
+    curMdl = NET_BUFFER_CURRENT_MDL(curNb);
+    NdisQueryMdl(curMdl, &bufferStart, &mdlLen, LowPagePriority);
+    if (!curMdl) {
+        ovsActionStats.noResource++;
+        return NDIS_STATUS_RESOURCES;
+    }
+
+    curMdlOffset = NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
+    mdlLen -= curMdlOffset;
+    ASSERT(mdlLen >= MPLS_HLEN);
+
+    ethHdr = (EthHdr *)(bufferStart + curMdlOffset);
+    RtlMoveMemory(ethHdr, (UINT8*)ethHdr + MPLS_HLEN, sizeof(*ethHdr));
+    ethHdr->Type = mpls->mpls_ethertype;
+
+    mplsHdr = (MPLSHdr *)(ethHdr + 1);
+    mplsHdr->lse = mpls->mpls_lse;
+
+    layers->l3Offset += MPLS_HLEN;
+    layers->l4Offset += MPLS_HLEN;
+
     return NDIS_STATUS_SUCCESS;
 }
 
@@ -1523,6 +1651,50 @@ OvsActionsExecute(POVS_SWITCH_CONTEXT switchContext,
             break;
         }
 
+        case OVS_ACTION_ATTR_PUSH_MPLS:
+        {
+            if (ovsFwdCtx.destPortsSizeOut > 0 || ovsFwdCtx.tunnelTxNic != NULL
+                || ovsFwdCtx.tunnelRxNic != NULL) {
+                status = OvsOutputBeforeSetAction(&ovsFwdCtx);
+                if (status != NDIS_STATUS_SUCCESS) {
+                    dropReason = L"OVS-adding destination failed";
+                    goto dropit;
+                }
+            }
+
+            status = OvsActionMplsPush(&ovsFwdCtx,
+                                       (struct ovs_action_push_mpls *)NlAttrGet
+                                       ((const PNL_ATTR)a));
+            if (status != NDIS_STATUS_SUCCESS) {
+                dropReason = L"OVS-push MPLS action failed";
+                goto dropit;
+            }
+            layers->l3Offset += MPLS_HLEN;
+            layers->l4Offset += MPLS_HLEN;
+            break;
+        }
+
+        case OVS_ACTION_ATTR_POP_MPLS:
+        {
+            if (ovsFwdCtx.destPortsSizeOut > 0 || ovsFwdCtx.tunnelTxNic != NULL
+                || ovsFwdCtx.tunnelRxNic != NULL) {
+                status = OvsOutputBeforeSetAction(&ovsFwdCtx);
+                if (status != NDIS_STATUS_SUCCESS) {
+                    dropReason = L"OVS-adding destination failed";
+                    goto dropit;
+                }
+            }
+
+            status = OvsActionMplsPop(&ovsFwdCtx, NlAttrGetBe16(a));
+            if (status != NDIS_STATUS_SUCCESS) {
+                dropReason = L"OVS-pop MPLS action failed";
+                goto dropit;
+            }
+            layers->l3Offset -= MPLS_HLEN;
+            layers->l4Offset -= MPLS_HLEN;
+            break;
+        }
+
         case OVS_ACTION_ATTR_USERSPACE:
         {
             PNL_ATTR userdataAttr;
diff --git a/datapath-windows/ovsext/DpInternal.h b/datapath-windows/ovsext/DpInternal.h
index 466a33a48..72e9b208a 100644
--- a/datapath-windows/ovsext/DpInternal.h
+++ b/datapath-windows/ovsext/DpInternal.h
@@ -20,6 +20,7 @@
 #include <netioapi.h>
 #define IFNAMSIZ IF_NAMESIZE
 #include "../ovsext/Netlink/Netlink.h"
+#include "Mpls.h"
 
 #define OVS_DP_NUMBER   ((uint32_t) 0)
 
@@ -125,7 +126,7 @@ typedef struct L2Key {
     uint8_t dlDst[6];            /* Ethernet destination address. */
     ovs_be16 vlanTci;            /* If 802.1Q, TCI | VLAN_CFI; otherwise 0. */
     ovs_be16 dlType;             /* Ethernet frame type. */
-} L2Key;  /* Size of 24 byte. */
+} L2Key; /* Size of 24 byte. */
 
 /* Number of packet attributes required to store OVS tunnel key. */
 #define NUM_PKT_ATTR_REQUIRED 3
@@ -147,16 +148,23 @@ typedef union OvsIPv4TunnelKey {
         };
     };
     uint64_t attr[NUM_PKT_ATTR_REQUIRED];
-} OvsIPv4TunnelKey;
+} OvsIPv4TunnelKey; /* Size of 24 byte. */
+
+typedef struct MplsKey {
+    ovs_be32 lse;                /* MPLS topmost label stack entry. */
+    uint8    pad[4];
+} MplsKey; /* Size of 8 bytes. */
 
 typedef __declspec(align(8)) struct OvsFlowKey {
     OvsIPv4TunnelKey tunKey;     /* 24 bytes */
     L2Key l2;                    /* 24 bytes */
     union {
+        /* These headers are mutually exclusive. */
         IpKey ipKey;             /* size 16 */
         ArpKey arpKey;           /* size 24 */
         Ipv6Key ipv6Key;         /* size 48 */
         Icmp6Key icmp6Key;       /* size 72 */
+        MplsKey mplsKey;         /* size 8 */
     };
 } OvsFlowKey;
 
diff --git a/datapath-windows/ovsext/Ethernet.h b/datapath-windows/ovsext/Ethernet.h
index 22aa27c9d..1d69d475e 100644
--- a/datapath-windows/ovsext/Ethernet.h
+++ b/datapath-windows/ovsext/Ethernet.h
@@ -66,6 +66,8 @@ typedef enum {
     ETH_TYPE_CDP         = 0x2000,
     ETH_TYPE_802_1PQ     = 0x8100, // not really a DIX type, but used as such
     ETH_TYPE_LLC         = 0xFFFF, // 0xFFFF is IANA reserved, used to mark LLC
+    ETH_TYPE_MPLS        = 0x8847,
+    ETH_TYPE_MPLS_MCAST  = 0x8848,
 } Eth_DixType;
 
 typedef enum {
diff --git a/datapath-windows/ovsext/Flow.c b/datapath-windows/ovsext/Flow.c
index 31ddc6681..a2f053542 100644
--- a/datapath-windows/ovsext/Flow.c
+++ b/datapath-windows/ovsext/Flow.c
@@ -80,6 +80,8 @@ static NTSTATUS _MapFlowIpv6KeyToNlKey(PNL_BUFFER nlBuf,
                                        Icmp6Key *ipv6FlowPutIcmpKey);
 static NTSTATUS _MapFlowArpKeyToNlKey(PNL_BUFFER nlBuf,
                                       ArpKey *arpFlowPutKey);
+static NTSTATUS _MapFlowMplsKeyToNlKey(PNL_BUFFER nlBuf,
+                                       MplsKey *mplsFlowPutKey);
 
 static NTSTATUS OvsDoDumpFlows(OvsFlowDumpInput *dumpInput,
                                OvsFlowDumpOutput *dumpOutput,
@@ -108,7 +110,7 @@ const NL_POLICY nlFlowPolicy[] = {
 
 /* For Parsing nested OVS_FLOW_ATTR_KEY attributes.
  * Some of the attributes like OVS_KEY_ATTR_RECIRC_ID
- * & OVS_KEY_ATTR_MPLS are not supported yet. */
+ * are not supported yet. */
 
 const NL_POLICY nlFlowKeyPolicy[] = {
     [OVS_KEY_ATTR_ENCAP] = {.type = NL_A_VAR_LEN, .optional = TRUE},
@@ -872,6 +874,13 @@ MapFlowKeyToNlKey(PNL_BUFFER nlBuf,
         break;
         }
 
+        case ETH_TYPE_MPLS:
+        case ETH_TYPE_MPLS_MCAST: {
+        MplsKey *mplsFlowPutKey = &(flowKey->mplsKey);
+        rc = _MapFlowMplsKeyToNlKey(nlBuf, mplsFlowPutKey);
+        break;
+        }
+
         default:
         break;
     }
@@ -1194,6 +1203,31 @@ done:
 
 /*
  *----------------------------------------------------------------------------
+ *  _MapFlowMplsKeyToNlKey --
+ *    Maps _MapFlowMplsKeyToNlKey to OVS_KEY_ATTR_MPLS attribute.
+ *----------------------------------------------------------------------------
+ */
+static NTSTATUS
+_MapFlowMplsKeyToNlKey(PNL_BUFFER nlBuf, MplsKey *mplsFlowPutKey)
+{
+    NTSTATUS rc = STATUS_SUCCESS;
+    struct ovs_key_mpls *mplsKey;
+
+    mplsKey = (struct ovs_key_mpls *)
+        NlMsgPutTailUnspecUninit(nlBuf, OVS_KEY_ATTR_MPLS, sizeof(*mplsKey));
+    if (!mplsKey) {
+        rc = STATUS_UNSUCCESSFUL;
+        goto done;
+    }
+
+    mplsKey->mpls_lse = mplsFlowPutKey->lse;
+
+done:
+    return rc;
+}
+
+/*
+ *----------------------------------------------------------------------------
  *  _MapNlToFlowPut --
  *    Maps input netlink message to OvsFlowPut.
  *----------------------------------------------------------------------------
@@ -1469,8 +1503,26 @@ _MapKeyAttrToFlowPut(PNL_ATTR *keyAttrs,
             arpFlowPutKey->pad[1] = 0;
             arpFlowPutKey->pad[2] = 0;
             destKey->l2.keyLen += OVS_ARP_KEY_SIZE;
-            break;
         }
+        break;
+    }
+    case ETH_TYPE_MPLS:
+    case ETH_TYPE_MPLS_MCAST: {
+
+        if (keyAttrs[OVS_KEY_ATTR_MPLS]) {
+            MplsKey *mplsFlowPutKey = &destKey->mplsKey;
+            const struct ovs_key_mpls *mplsKey;
+
+            mplsKey = NlAttrGet(keyAttrs[OVS_KEY_ATTR_MPLS]);
+
+            mplsFlowPutKey->lse = mplsKey->mpls_lse;
+            mplsFlowPutKey->pad[0] = 0;
+            mplsFlowPutKey->pad[1] = 0;
+            mplsFlowPutKey->pad[2] = 0;
+            mplsFlowPutKey->pad[3] = 0;
+            destKey->l2.keyLen += sizeof(MplsKey);
+        }
+        break;
     }
     }
 }
@@ -1734,10 +1786,10 @@ OvsExtractFlow(const NET_BUFFER_LIST *packet,
             flow->l2.vlanTci = 0;
         }
         /*
-        * XXX
-        * Please note after this point, src mac and dst mac should
-        * not be accessed through eth
-        */
+         * XXX
+         * Please note after this point, src mac and dst mac should
+         * not be accessed through eth
+         */
         eth = (Eth_Header *)((UINT8 *)eth + offset);
     }
 
@@ -1868,6 +1920,44 @@ OvsExtractFlow(const NET_BUFFER_LIST *packet,
                 memcpy(arpKey->arpTha, arp->arp_tha, ETH_ADDR_LENGTH);
             }
         }
+    } else if (OvsEthertypeIsMpls(flow->l2.dlType)) {
+        MPLSHdr mplsStorage;
+        const MPLSHdr *mpls;
+        MplsKey *mplsKey = &flow->mplsKey;
+        ((UINT64 *)mplsKey)[0] = 0;
+
+        /*
+         * In the presence of an MPLS label stack the end of the L2
+         * header and the beginning of the L3 header differ.
+         *
+         * A network packet may contain multiple MPLS labels, but we
+         * are only interested in the topmost label stack entry.
+         *
+         * Advance network header to the beginning of the L3 header.
+         * layers->l3Offset corresponds to the end of the L2 header.
+         */
+        for (UINT32 i = 0; i < FLOW_MAX_MPLS_LABELS; i++) {
+            mpls = OvsGetMpls(packet, layers->l3Offset, &mplsStorage);
+            if (!mpls) {
+                break;
+            }
+
+            /* Keep only the topmost MPLS label stack entry. */
+            if (i == 0) {
+                mplsKey->lse = mpls->lse;
+            }
+
+            layers->l3Offset += MPLS_HLEN;
+            layers->l4Offset += MPLS_HLEN;
+
+            if (mpls->lse & htonl(MPLS_BOS_MASK)) {
+                /*
+                 * Bottom of Stack bit is set, which means there are no
+                 * remaining MPLS labels in the packet.
+                 */
+                break;
+            }
+        }
     }
 
     return NDIS_STATUS_SUCCESS;
diff --git a/datapath-windows/ovsext/Mpls.h b/datapath-windows/ovsext/Mpls.h
new file mode 100644
index 000000000..6e53e46db
--- /dev/null
+++ b/datapath-windows/ovsext/Mpls.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2015 Cloudbase Solutions Srl
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __MPLS_H_
+#define __MPLS_H_ 1
+
+#include "precomp.h"
+#include "Ethernet.h"
+
+/*
+ * MPLS definitions
+ */
+#define FLOW_MAX_MPLS_LABELS    3
+
+#define MPLS_HLEN               4
+#define MPLS_BOS_MASK           0x00000100
+
+/* Reference: RFC 5462, RFC 3032
+ *
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                Label                  | TC  |S|       TTL     |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ *	Label:  Label Value, 20 bits
+ *	TC:     Traffic Class field, 3 bits
+ *	S:      Bottom of Stack, 1 bit
+ *	TTL:    Time to Live, 8 bits
+ */
+
+typedef struct MPLSHdr {
+    ovs_be32 lse;
+} MPLSHdr;
+
+__inline BOOLEAN
+OvsEthertypeIsMpls(ovs_be16 ethertype)
+{
+    return ethertype == htons(ETH_TYPE_MPLS) ||
+           ethertype == htons(ETH_TYPE_MPLS_MCAST);
+}
+
+#endif /* __MPLS_H_ */
diff --git a/datapath-windows/ovsext/NetProto.h b/datapath-windows/ovsext/NetProto.h
index e93501666..c18135c53 100644
--- a/datapath-windows/ovsext/NetProto.h
+++ b/datapath-windows/ovsext/NetProto.h
@@ -19,7 +19,9 @@
 
 #include "precomp.h"
 #include "Ethernet.h"
+#include "Mpls.h"
 
+#define ETH_HEADER_LENGTH  14
 #define ETH_ADDR_LENGTH    6
 /*
  * There is a more inclusive definition of ethernet header (Eth_Header) in
diff --git a/datapath-windows/ovsext/Netlink/Netlink.h b/datapath-windows/ovsext/Netlink/Netlink.h
index d27073731..99665fb92 100644
--- a/datapath-windows/ovsext/Netlink/Netlink.h
+++ b/datapath-windows/ovsext/Netlink/Netlink.h
@@ -123,6 +123,7 @@ const PVOID NlAttrGet(const PNL_ATTR nla);
 const PVOID NlAttrGetUnspec(const PNL_ATTR nla, UINT32 size);
 BE64 NlAttrGetBe64(const PNL_ATTR nla);
 BE32 NlAttrGetBe32(const PNL_ATTR nla);
+BE16 NlAttrGetBe16(const PNL_ATTR nla);
 UINT8 NlAttrGetU8(const PNL_ATTR nla);
 UINT16 NlAttrGetU16(const PNL_ATTR nla);
 UINT32 NlAttrGetU32(const PNL_ATTR nla);
diff --git a/datapath-windows/ovsext/PacketParser.c b/datapath-windows/ovsext/PacketParser.c
index bba2631b7..bd6910c6d 100644
--- a/datapath-windows/ovsext/PacketParser.c
+++ b/datapath-windows/ovsext/PacketParser.c
@@ -84,8 +84,8 @@ OvsGetPacketBytes(const NET_BUFFER_LIST *nbl,
 
 NDIS_STATUS
 OvsParseIPv6(const NET_BUFFER_LIST *packet,
-          OvsFlowKey *key,
-          POVS_PACKET_HDR_INFO layers)
+             OvsFlowKey *key,
+             POVS_PACKET_HDR_INFO layers)
 {
     UINT16 ofs = layers->l3Offset;
     IPv6Hdr ipv6HdrStorage;
@@ -178,8 +178,8 @@ OvsParseIPv6(const NET_BUFFER_LIST *packet,
 
 VOID
 OvsParseTcp(const NET_BUFFER_LIST *packet,
-         L4Key *flow,
-         POVS_PACKET_HDR_INFO layers)
+            L4Key *flow,
+            POVS_PACKET_HDR_INFO layers)
 {
     TCPHdr tcpStorage;
     const TCPHdr *tcp = OvsGetTcp(packet, layers->l4Offset, &tcpStorage);
@@ -208,8 +208,8 @@ OvsParseSctp(const NET_BUFFER_LIST *packet,
 
 VOID
 OvsParseUdp(const NET_BUFFER_LIST *packet,
-         L4Key *flow,
-         POVS_PACKET_HDR_INFO layers)
+            L4Key *flow,
+            POVS_PACKET_HDR_INFO layers)
 {
     UDPHdr udpStorage;
     const UDPHdr *udp = OvsGetUdp(packet, layers->l4Offset, &udpStorage);
diff --git a/datapath-windows/ovsext/PacketParser.h b/datapath-windows/ovsext/PacketParser.h
index 7b8e656ed..47d227f59 100644
--- a/datapath-windows/ovsext/PacketParser.h
+++ b/datapath-windows/ovsext/PacketParser.h
@@ -151,4 +151,11 @@ OvsGetIcmp(const NET_BUFFER_LIST *packet,
     return OvsGetPacketBytes(packet, sizeof *storage, ofs, storage);
 }
 
+static const MPLSHdr *
+OvsGetMpls(const NET_BUFFER_LIST *packet,
+           UINT32 ofs,
+           MPLSHdr *storage)
+{
+    return OvsGetPacketBytes(packet, sizeof *storage, ofs, storage);
+}
 #endif /* __PACKET_PARSER_H_ */
diff --git a/datapath-windows/ovsext/ovsext.vcxproj b/datapath-windows/ovsext/ovsext.vcxproj
index 231ac83b7..fd10809dd 100644
--- a/datapath-windows/ovsext/ovsext.vcxproj
+++ b/datapath-windows/ovsext/ovsext.vcxproj
@@ -83,6 +83,7 @@
     <ClInclude Include="Gre.h" />
     <ClInclude Include="IpHelper.h" />
     <ClInclude Include="Jhash.h" />
+    <ClInclude Include="Mpls.h" />
     <ClInclude Include="Netlink/Netlink.h" />
     <ClInclude Include="Netlink/NetlinkBuf.h" />
     <ClInclude Include="Netlink/NetlinkProto.h" />