datapath-windows/ovsext/Vxlan.c

   1 /*
   2  * Copyright (c) 2014 VMware, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include "precomp.h"
  18 #include "NetProto.h"
  19 #include "Switch.h"
  20 #include "Vport.h"
  21 #include "Flow.h"
  22 #include "Vxlan.h"
  23 #include "IpHelper.h"
  24 #include "Checksum.h"
  25 #include "User.h"
  26 #include "PacketIO.h"
  27 #include "Flow.h"
  28 #include "PacketParser.h"
  29
  30 #pragma warning( push )
  31 #pragma warning( disable:4127 )
  32
  33
  34 #ifdef OVS_DBG_MOD
  35 #undef OVS_DBG_MOD
  36 #endif
  37 #define OVS_DBG_MOD OVS_DBG_VXLAN
  38 #include "Debug.h"
  39
  40 /* Helper macro to check if a VXLAN ID is valid. */
  41 #define VXLAN_ID_IS_VALID(vxlanID) (0 < (vxlanID) && (vxlanID) <= 0xffffff)
  42 #define VXLAN_TUNNELID_TO_VNI(_tID)   (UINT32)(((UINT64)(_tID)) >> 40)
  43 #define VXLAN_VNI_TO_TUNNELID(_vni) (((UINT64)(_vni)) << 40)
  44 #define IP_DF_NBO 0x0040
  45 #define VXLAN_DEFAULT_TTL 64
  46 #define VXLAN_MULTICAST_TTL 64
  47 #define VXLAN_DEFAULT_INSTANCE_ID 1
  48
  49 /* Move to a header file */
  50 extern POVS_SWITCH_CONTEXT gOvsSwitchContext;
  51
  52 /*
  53  *----------------------------------------------------------------------------
  54  * This function verifies if the VXLAN tunnel already exists, in order to
  55  * avoid sending a duplicate request to the WFP base filtering engine.
  56  *----------------------------------------------------------------------------
  57  */
  58 static BOOLEAN
  59 OvsIsTunnelFilterCreated(POVS_SWITCH_CONTEXT switchContext,
  60                          UINT16 udpPortDest)
  61 {
  62     for (UINT hash = 0; hash < OVS_MAX_VPORT_ARRAY_SIZE; hash++) {
  63         PLIST_ENTRY head, link, next;
  64
  65         head = &(switchContext->portNoHashArray[hash & OVS_VPORT_MASK]);
  66         LIST_FORALL_SAFE(head, link, next) {
  67             POVS_VPORT_ENTRY vport = NULL;
  68             POVS_VXLAN_VPORT vxlanPort = NULL;
  69             vport = CONTAINING_RECORD(link, OVS_VPORT_ENTRY, portNoLink);
  70             vxlanPort = (POVS_VXLAN_VPORT)vport->priv;
  71             if (vxlanPort) {
  72                 if ((udpPortDest == vxlanPort->dstPort)) {
  73                     /* The VXLAN tunnel was already created. */
  74                     return TRUE;
  75                 }
  76             }
  77         }
  78     }
  79
  80     return FALSE;
  81 }
  82
  83 /*
  84  *----------------------------------------------------------------------------
  85  * This function allocates and initializes the OVS_VXLAN_VPORT. The function
  86  * also creates a WFP tunnel filter for the necessary destination port. The
  87  * tunnel filter create request is passed to the tunnel filter threads that
  88  * will complete the request at a later time when IRQL is lowered to
  89  * PASSIVE_LEVEL.
  90  *
  91  * udpDestPort: the vxlan is set as payload to a udp frame. If the destination
  92  * port of an udp frame is udpDestPort, we understand it to be vxlan.
  93  *----------------------------------------------------------------------------
  94  */
  95 NTSTATUS
  96 OvsInitVxlanTunnel(PIRP irp,
  97                    POVS_VPORT_ENTRY vport,
  98                    UINT16 udpDestPort,
  99                    PFNTunnelVportPendingOp callback,
 100                    PVOID tunnelContext)
 101 {
 102     NTSTATUS status = STATUS_SUCCESS;
 103     POVS_VXLAN_VPORT vxlanPort = NULL;
 104
 105     vxlanPort = OvsAllocateMemoryWithTag(sizeof (*vxlanPort),
 106                                          OVS_VXLAN_POOL_TAG);
 107     if (vxlanPort == NULL) {
 108         return STATUS_INSUFFICIENT_RESOURCES;
 109     }
 110
 111     RtlZeroMemory(vxlanPort, sizeof(*vxlanPort));
 112     vxlanPort->dstPort = udpDestPort;
 113     vport->priv = (PVOID)vxlanPort;
 114
 115     if (!OvsIsTunnelFilterCreated(gOvsSwitchContext, udpDestPort)) {
 116         status = OvsTunelFilterCreate(irp,
 117                                       udpDestPort,
 118                                       &vxlanPort->filterID,
 119                                       callback,
 120                                       tunnelContext);
 121     } else {
 122         status = STATUS_OBJECT_NAME_EXISTS;
 123     }
 124
 125     return status;
 126 }
 127
 128 /*
 129  *----------------------------------------------------------------------------
 130  * This function releases the OVS_VXLAN_VPORT. The function also deletes the
 131  * WFP tunnel filter previously created. The tunnel filter delete request is
 132  * passed to the tunnel filter threads that will complete the request at a
 133  * later time when IRQL is lowered to PASSIVE_LEVEL.
 134  *----------------------------------------------------------------------------
 135  */
 136 NTSTATUS
 137 OvsCleanupVxlanTunnel(PIRP irp,
 138                       POVS_VPORT_ENTRY vport,
 139                       PFNTunnelVportPendingOp callback,
 140                       PVOID tunnelContext)
 141 {
 142     NTSTATUS status = STATUS_SUCCESS;
 143     POVS_VXLAN_VPORT vxlanPort = NULL;
 144
 145     if (vport->ovsType != OVS_VPORT_TYPE_VXLAN ||
 146         vport->priv == NULL) {
 147         return STATUS_SUCCESS;
 148     }
 149
 150     vxlanPort = (POVS_VXLAN_VPORT)vport->priv;
 151
 152     if (vxlanPort->filterID != 0) {
 153         status = OvsTunelFilterDelete(irp,
 154                                       vxlanPort->filterID,
 155                                       callback,
 156                                       tunnelContext);
 157     }
 158
 159     OvsFreeMemoryWithTag(vport->priv, OVS_VXLAN_POOL_TAG);
 160     vport->priv = NULL;
 161
 162     return status;
 163 }
 164
 165
 166 /*
 167  *----------------------------------------------------------------------------
 168  * OvsDoEncapVxlan
 169  *     Encapsulates the packet.
 170  *----------------------------------------------------------------------------
 171  */
 172 static __inline NDIS_STATUS
 173 OvsDoEncapVxlan(PNET_BUFFER_LIST curNbl,
 174                 OvsIPv4TunnelKey *tunKey,
 175                 POVS_FWD_INFO fwdInfo,
 176                 POVS_PACKET_HDR_INFO layers,
 177                 POVS_SWITCH_CONTEXT switchContext,
 178                 PNET_BUFFER_LIST *newNbl)
 179 {
 180     NDIS_STATUS status;
 181     PNET_BUFFER curNb;
 182     PMDL curMdl;
 183     PUINT8 bufferStart;
 184     EthHdr *ethHdr;
 185     IPHdr *ipHdr;
 186     UDPHdr *udpHdr;
 187     VXLANHdr *vxlanHdr;
 188     UINT32 headRoom = OvsGetVxlanTunHdrSize();
 189     UINT32 packetLength;
 190
 191     /*
 192      * XXX: the assumption currently is that the NBL is owned by OVS, and
 193      * headroom has already been allocated as part of allocating the NBL and
 194      * MDL.
 195      */
 196     curNb = NET_BUFFER_LIST_FIRST_NB(curNbl);
 197     packetLength = NET_BUFFER_DATA_LENGTH(curNb);
 198     if (layers->isTcp) {
 199         NDIS_TCP_LARGE_SEND_OFFLOAD_NET_BUFFER_LIST_INFO tsoInfo;
 200
 201         tsoInfo.Value = NET_BUFFER_LIST_INFO(curNbl,
 202                 TcpLargeSendNetBufferListInfo);
 203         OVS_LOG_TRACE("MSS %u packet len %u", tsoInfo.LsoV1Transmit.MSS, packetLength);
 204         if (tsoInfo.LsoV1Transmit.MSS) {
 205             OVS_LOG_TRACE("l4Offset %d", layers->l4Offset);
 206             *newNbl = OvsTcpSegmentNBL(switchContext, curNbl, layers,
 207                         tsoInfo.LsoV1Transmit.MSS, headRoom);
 208             if (*newNbl == NULL) {
 209                 OVS_LOG_ERROR("Unable to segment NBL");
 210                 return NDIS_STATUS_FAILURE;
 211             }
 212         }
 213     }
 214     /* If we didn't split the packet above, make a copy now */
 215     if (*newNbl == NULL) {
 216         *newNbl = OvsPartialCopyNBL(switchContext, curNbl, 0, headRoom,
 217                                     FALSE /*NBL info*/);
 218         if (*newNbl == NULL) {
 219             OVS_LOG_ERROR("Unable to copy NBL");
 220             return NDIS_STATUS_FAILURE;
 221         }
 222     }
 223
 224     curNbl = *newNbl;
 225     for (curNb = NET_BUFFER_LIST_FIRST_NB(curNbl); curNb != NULL;
 226             curNb = curNb->Next) {
 227         status = NdisRetreatNetBufferDataStart(curNb, headRoom, 0, NULL);
 228         if (status != NDIS_STATUS_SUCCESS) {
 229             goto ret_error;
 230         }
 231
 232         curMdl = NET_BUFFER_CURRENT_MDL(curNb);
 233         bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority);
 234         if (!bufferStart) {
 235             status = NDIS_STATUS_RESOURCES;
 236             goto ret_error;
 237         }
 238
 239         bufferStart += NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
 240         if (NET_BUFFER_NEXT_NB(curNb)) {
 241             OVS_LOG_TRACE("nb length %u next %u", NET_BUFFER_DATA_LENGTH(curNb),
 242                           NET_BUFFER_DATA_LENGTH(curNb->Next));
 243         }
 244
 245         /* L2 header */
 246         ethHdr = (EthHdr *)bufferStart;
 247         ASSERT(((PCHAR)&fwdInfo->dstMacAddr + sizeof fwdInfo->dstMacAddr) ==
 248                (PCHAR)&fwdInfo->srcMacAddr);
 249         NdisMoveMemory(ethHdr->Destination, fwdInfo->dstMacAddr,
 250                        sizeof ethHdr->Destination + sizeof ethHdr->Source);
 251         ethHdr->Type = htons(ETH_TYPE_IPV4);
 252
 253         // XXX: question: there are fields in the OvsIPv4TunnelKey for ttl and such,
 254         // should we use those values instead? or will they end up being
 255         // uninitialized;
 256         /* IP header */
 257         ipHdr = (IPHdr *)((PCHAR)ethHdr + sizeof *ethHdr);
 258
 259         ipHdr->ihl = sizeof *ipHdr / 4;
 260         ipHdr->version = IPV4;
 261         ipHdr->tos = 0;
 262         ipHdr->tot_len = htons(NET_BUFFER_DATA_LENGTH(curNb) - sizeof *ethHdr);
 263         ipHdr->id = 0;
 264         ipHdr->frag_off = IP_DF_NBO;
 265         ipHdr->ttl = tunKey->ttl ? tunKey->ttl : VXLAN_DEFAULT_TTL;
 266         ipHdr->protocol = IPPROTO_UDP;
 267         ASSERT(tunKey->dst == fwdInfo->dstIpAddr);
 268         ASSERT(tunKey->src == fwdInfo->srcIpAddr || tunKey->src == 0);
 269         ipHdr->saddr = fwdInfo->srcIpAddr;
 270         ipHdr->daddr = fwdInfo->dstIpAddr;
 271         ipHdr->check = 0;
 272         ipHdr->check = IPChecksum((UINT8 *)ipHdr, sizeof *ipHdr, 0);
 273
 274         /* UDP header */
 275         udpHdr = (UDPHdr *)((PCHAR)ipHdr + sizeof *ipHdr);
 276         udpHdr->source = htons(tunKey->flow_hash | 32768);
 277         udpHdr->dest = htons(tunKey->dst_port);
 278         udpHdr->len = htons(NET_BUFFER_DATA_LENGTH(curNb) - headRoom +
 279                             sizeof *udpHdr + sizeof *vxlanHdr);
 280         udpHdr->check = 0;
 281
 282         /* VXLAN header */
 283         vxlanHdr = (VXLANHdr *)((PCHAR)udpHdr + sizeof *udpHdr);
 284         vxlanHdr->flags1 = 0;
 285         vxlanHdr->locallyReplicate = 0;
 286         vxlanHdr->flags2 = 0;
 287         vxlanHdr->reserved1 = 0;
 288         if (tunKey->flags | OVS_TNL_F_KEY) {
 289             vxlanHdr->vxlanID = VXLAN_TUNNELID_TO_VNI(tunKey->tunnelId);
 290             vxlanHdr->instanceID = 1;
 291         }
 292         vxlanHdr->reserved2 = 0;
 293     }
 294     return STATUS_SUCCESS;
 295
 296 ret_error:
 297     OvsCompleteNBL(switchContext, *newNbl, TRUE);
 298     *newNbl = NULL;
 299     return status;
 300 }
 301
 302
 303 /*
 304  *----------------------------------------------------------------------------
 305  * OvsEncapVxlan --
 306  *     Encapsulates the packet if L2/L3 for destination resolves. Otherwise,
 307  *     enqueues a callback that does encapsulatation after resolution.
 308  *----------------------------------------------------------------------------
 309  */
 310 NDIS_STATUS
 311 OvsEncapVxlan(PNET_BUFFER_LIST curNbl,
 312               OvsIPv4TunnelKey *tunKey,
 313               POVS_SWITCH_CONTEXT switchContext,
 314               POVS_PACKET_HDR_INFO layers,
 315               PNET_BUFFER_LIST *newNbl)
 316 {
 317     NTSTATUS status;
 318     OVS_FWD_INFO fwdInfo;
 319
 320     status = OvsLookupIPFwdInfo(tunKey->dst, &fwdInfo);
 321     if (status != STATUS_SUCCESS) {
 322         OvsFwdIPHelperRequest(NULL, 0, tunKey, NULL, NULL, NULL);
 323         // return NDIS_STATUS_PENDING;
 324         /*
 325          * XXX: Don't know if the completionList will make any sense when
 326          * accessed in the callback. Make sure the caveats are known.
 327          *
 328          * XXX: This code will work once we are able to grab locks in the
 329          * callback.
 330          */
 331         return NDIS_STATUS_FAILURE;
 332     }
 333
 334     return OvsDoEncapVxlan(curNbl, tunKey, &fwdInfo, layers,
 335                            switchContext, newNbl);
 336 }
 337
 338
 339 /*
 340  *----------------------------------------------------------------------------
 341  * OvsIpHlprCbVxlan --
 342  *     Callback function for IP helper.
 343  *     XXX: not used currently
 344  *----------------------------------------------------------------------------
 345  */
 346 static VOID
 347 OvsIpHlprCbVxlan(PNET_BUFFER_LIST curNbl,
 348                  UINT32 inPort,
 349                  OvsIPv4TunnelKey *tunKey,
 350                  PVOID cbData1,
 351                  PVOID cbData2,
 352                  NTSTATUS result,
 353                  POVS_FWD_INFO fwdInfo)
 354 {
 355     OVS_PACKET_HDR_INFO layers;
 356     OvsFlowKey key;
 357     NDIS_STATUS status;
 358     UNREFERENCED_PARAMETER(inPort);
 359
 360     status = OvsExtractFlow(curNbl, inPort, &key, &layers, NULL);
 361     if (result == STATUS_SUCCESS) {
 362         status = OvsDoEncapVxlan(curNbl, tunKey, fwdInfo, &layers,
 363                 (POVS_SWITCH_CONTEXT)cbData1, NULL);
 364     } else {
 365         status = NDIS_STATUS_FAILURE;
 366     }
 367
 368     if (status != NDIS_STATUS_SUCCESS) {
 369         // XXX: Free up the NBL;
 370         return;
 371     }
 372
 373     OvsLookupFlowOutput((POVS_SWITCH_CONTEXT)cbData1, cbData2, curNbl);
 374 }
 375
 376 /*
 377  *----------------------------------------------------------------------------
 378  * OvsCalculateUDPChecksum
 379  *     Calculate UDP checksum
 380  *----------------------------------------------------------------------------
 381  */
 382 static __inline NDIS_STATUS
 383 OvsCalculateUDPChecksum(PNET_BUFFER_LIST curNbl,
 384                         PNET_BUFFER curNb,
 385                         IPHdr *ipHdr,
 386                         UDPHdr *udpHdr,
 387                         UINT32 packetLength)
 388 {
 389     NDIS_TCP_IP_CHECKSUM_NET_BUFFER_LIST_INFO csumInfo;
 390     UINT16 checkSum;
 391
 392     csumInfo.Value = NET_BUFFER_LIST_INFO(curNbl, TcpIpChecksumNetBufferListInfo);
 393
 394     /* Next check if UDP checksum has been calculated. */
 395     if (!csumInfo.Receive.UdpChecksumSucceeded) {
 396         UINT32 l4Payload;
 397
 398         checkSum = udpHdr->check;
 399
 400         l4Payload = packetLength - sizeof(EthHdr) - ipHdr->ihl * 4;
 401         udpHdr->check = 0;
 402         udpHdr->check =
 403             IPPseudoChecksum((UINT32 *)&ipHdr->saddr,
 404                              (UINT32 *)&ipHdr->daddr,
 405                              IPPROTO_UDP, (UINT16)l4Payload);
 406         udpHdr->check = CalculateChecksumNB(curNb, (UINT16)l4Payload,
 407             sizeof(EthHdr) + ipHdr->ihl * 4);
 408         if (checkSum != udpHdr->check) {
 409             OVS_LOG_TRACE("UDP checksum incorrect.");
 410             return NDIS_STATUS_INVALID_PACKET;
 411         }
 412     }
 413
 414     csumInfo.Receive.UdpChecksumSucceeded = 1;
 415     NET_BUFFER_LIST_INFO(curNbl, TcpIpChecksumNetBufferListInfo) = csumInfo.Value;
 416     return NDIS_STATUS_SUCCESS;
 417 }
 418
 419 /*
 420  *----------------------------------------------------------------------------
 421  * OvsDecapVxlan
 422  *     Decapsulates to tunnel header in 'curNbl' and puts into 'tunKey'.
 423  *----------------------------------------------------------------------------
 424  */
 425 NDIS_STATUS
 426 OvsDecapVxlan(POVS_SWITCH_CONTEXT switchContext,
 427               PNET_BUFFER_LIST curNbl,
 428               OvsIPv4TunnelKey *tunKey,
 429               PNET_BUFFER_LIST *newNbl)
 430 {
 431     PNET_BUFFER curNb;
 432     PMDL curMdl;
 433     EthHdr *ethHdr;
 434     IPHdr *ipHdr;
 435     UDPHdr *udpHdr;
 436     VXLANHdr *vxlanHdr;
 437     UINT32 tunnelSize = 0, packetLength = 0;
 438     PUINT8 bufferStart;
 439     NDIS_STATUS status;
 440
 441     /* Check the the length of the UDP payload */
 442     curNb = NET_BUFFER_LIST_FIRST_NB(curNbl);
 443     packetLength = NET_BUFFER_DATA_LENGTH(curNb);
 444     tunnelSize = OvsGetVxlanTunHdrSize();
 445     if (packetLength <= tunnelSize) {
 446         return NDIS_STATUS_INVALID_LENGTH;
 447     }
 448
 449     /*
 450      * Create a copy of the NBL so that we have all the headers in one MDL.
 451      */
 452     *newNbl = OvsPartialCopyNBL(switchContext, curNbl,
 453                                 tunnelSize + OVS_DEFAULT_COPY_SIZE, 0,
 454                                 TRUE /*copy NBL info */);
 455
 456     if (*newNbl == NULL) {
 457         return NDIS_STATUS_RESOURCES;
 458     }
 459
 460     /* XXX: Handle VLAN header. */
 461     curNbl = *newNbl;
 462     curNb = NET_BUFFER_LIST_FIRST_NB(curNbl);
 463     curMdl = NET_BUFFER_CURRENT_MDL(curNb);
 464     bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority) +
 465                   NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
 466     if (!bufferStart) {
 467         status = NDIS_STATUS_RESOURCES;
 468         goto dropNbl;
 469     }
 470
 471     ethHdr = (EthHdr *)bufferStart;
 472     /* XXX: Handle IP options. */
 473     ipHdr = (IPHdr *)((PCHAR)ethHdr + sizeof *ethHdr);
 474     tunKey->src = ipHdr->saddr;
 475     tunKey->dst = ipHdr->daddr;
 476     tunKey->tos = ipHdr->tos;
 477     tunKey->ttl = ipHdr->ttl;
 478     tunKey->pad = 0;
 479     udpHdr = (UDPHdr *)((PCHAR)ipHdr + sizeof *ipHdr);
 480
 481     /* Validate if NIC has indicated checksum failure. */
 482     status = OvsValidateUDPChecksum(curNbl, udpHdr->check == 0);
 483     if (status != NDIS_STATUS_SUCCESS) {
 484         goto dropNbl;
 485     }
 486
 487     /* Calculate and verify UDP checksum if NIC didn't do it. */
 488     if (udpHdr->check != 0) {
 489         status = OvsCalculateUDPChecksum(curNbl, curNb, ipHdr, udpHdr, packetLength);
 490         if (status != NDIS_STATUS_SUCCESS) {
 491             goto dropNbl;
 492         }
 493     }
 494
 495     vxlanHdr = (VXLANHdr *)((PCHAR)udpHdr + sizeof *udpHdr);
 496     if (vxlanHdr->instanceID) {
 497         tunKey->flags = OVS_TNL_F_KEY;
 498         tunKey->tunnelId = VXLAN_VNI_TO_TUNNELID(vxlanHdr->vxlanID);
 499     } else {
 500         tunKey->flags = 0;
 501         tunKey->tunnelId = 0;
 502     }
 503
 504     /* Clear out the receive flag for the inner packet. */
 505     NET_BUFFER_LIST_INFO(curNbl, TcpIpChecksumNetBufferListInfo) = 0;
 506     NdisAdvanceNetBufferDataStart(curNb, tunnelSize, FALSE, NULL);
 507     return NDIS_STATUS_SUCCESS;
 508
 509 dropNbl:
 510     OvsCompleteNBL(switchContext, *newNbl, TRUE);
 511     *newNbl = NULL;
 512     return status;
 513 }
 514
 515
 516 NDIS_STATUS
 517 OvsSlowPathDecapVxlan(const PNET_BUFFER_LIST packet,
 518                    OvsIPv4TunnelKey *tunnelKey)
 519 {
 520     NDIS_STATUS status = NDIS_STATUS_FAILURE;
 521     UDPHdr udpStorage;
 522     const UDPHdr *udp;
 523     VXLANHdr *VxlanHeader;
 524     VXLANHdr  VxlanHeaderBuffer;
 525     struct IPHdr ip_storage;
 526     const struct IPHdr *nh;
 527     OVS_PACKET_HDR_INFO layers;
 528
 529     layers.value = 0;
 530
 531     do {
 532         nh = OvsGetIp(packet, layers.l3Offset, &ip_storage);
 533         if (nh) {
 534             layers.l4Offset = layers.l3Offset + nh->ihl * 4;
 535         } else {
 536             break;
 537         }
 538
 539         /* make sure it's a VXLAN packet */
 540         udp = OvsGetUdp(packet, layers.l4Offset, &udpStorage);
 541         if (udp) {
 542             layers.l7Offset = layers.l4Offset + sizeof *udp;
 543         } else {
 544             break;
 545         }
 546
 547         VxlanHeader = (VXLANHdr *)OvsGetPacketBytes(packet,
 548                                                     sizeof(*VxlanHeader),
 549                                                     layers.l7Offset,
 550                                                     &VxlanHeaderBuffer);
 551
 552         if (VxlanHeader) {
 553             tunnelKey->src = nh->saddr;
 554             tunnelKey->dst = nh->daddr;
 555             tunnelKey->ttl = nh->ttl;
 556             tunnelKey->tos = nh->tos;
 557             if (VxlanHeader->instanceID) {
 558                 tunnelKey->flags = OVS_TNL_F_KEY;
 559                 tunnelKey->tunnelId = VXLAN_VNI_TO_TUNNELID(VxlanHeader->vxlanID);
 560             } else {
 561                 tunnelKey->flags = 0;
 562                 tunnelKey->tunnelId = 0;
 563             }
 564         } else {
 565             break;
 566         }
 567         status = NDIS_STATUS_SUCCESS;
 568
 569     } while(FALSE);
 570
 571     return status;
 572 }
 573
 574 #pragma warning( pop )