EdkModulePkg/Universal/Network/PxeBc/Dxe/pxe_bc_ip.c

   1 /*++
   2
   3 Copyright (c) 2006, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12 Module Name:
  13   pxe_bc_ip.c
  14
  15 Abstract:
  16
  17 --*/
  18
  19
  20 #include "Bc.h"
  21
  22 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
  23 BOOLEAN
  24 OnSameSubnet (
  25   IN UINTN           IpLength,
  26   IN EFI_IP_ADDRESS  *Ip1,
  27   IN EFI_IP_ADDRESS  *Ip2,
  28   IN EFI_IP_ADDRESS  *SubnetMask
  29   )
  30 /*++
  31
  32   Routine Description:
  33     Check if two IP addresses are on the same subnet.
  34
  35   Arguments:
  36     IpLength   - Length of IP address in bytes.
  37     Ip1        - IP address to check.
  38     Ip2        - IP address to check.
  39     SubnetMask - Subnet mask to check with.
  40
  41   Returns:
  42     TRUE       - IP addresses are on the same subnet.
  43     FALSE      - IP addresses are on different subnets.
  44
  45 --*/
  46 {
  47   if (IpLength == 0 || Ip1 == NULL || Ip2 == NULL || SubnetMask == NULL) {
  48     return FALSE;
  49   }
  50
  51   while (IpLength-- != 0) {
  52     if ((Ip1->v6.Addr[IpLength] ^ Ip2->v6.Addr[IpLength]) & SubnetMask->v6.Addr[IpLength]) {
  53       return FALSE;
  54     }
  55   }
  56
  57   return TRUE;
  58 }
  59
  60 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
  61 VOID
  62 IpAddRouter (
  63   IN PXE_BASECODE_DEVICE *Private,
  64   IN EFI_IP_ADDRESS      *RouterIpPtr
  65   )
  66 /*++
  67
  68   Routine Description:
  69     Add router to router table.
  70
  71   Arguments:
  72     Private     - Pointer PxeBc instance data.
  73     RouterIpPtr - Pointer to router IP address.
  74
  75   Returns:
  76     Nothing
  77
  78 --*/
  79 {
  80   EFI_PXE_BASE_CODE_MODE  *PxeBcMode;
  81   UINTN                   Index;
  82
  83   if (Private == NULL || RouterIpPtr == NULL) {
  84     return ;
  85   }
  86
  87   PxeBcMode = Private->EfiBc.Mode;
  88
  89   //
  90   // if we are filled up or this is not on the same subnet, forget it
  91   //
  92   if ((PxeBcMode->RouteTableEntries == PXE_ROUTER_TABLE_SIZE) ||
  93     !OnSameSubnet(Private->IpLength, &PxeBcMode->StationIp, RouterIpPtr, &PxeBcMode->SubnetMask)) {
  94     return ;
  95   }
  96   //
  97   // make sure we don't already have it
  98   //
  99   for (Index = 0; Index < PxeBcMode->RouteTableEntries; ++Index) {
 100     if (!CompareMem (
 101           &PxeBcMode->RouteTable[Index].GwAddr,
 102           RouterIpPtr,
 103           Private->IpLength
 104           )) {
 105       return ;
 106     }
 107   }
 108   //
 109   // keep it
 110   //
 111   ZeroMem (
 112     &PxeBcMode->RouteTable[PxeBcMode->RouteTableEntries],
 113     sizeof (EFI_PXE_BASE_CODE_ROUTE_ENTRY)
 114     );
 115
 116   CopyMem (
 117     &PxeBcMode->RouteTable[PxeBcMode->RouteTableEntries++].GwAddr,
 118     RouterIpPtr,
 119     Private->IpLength
 120     );
 121 }
 122
 123 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 124
 125 //
 126 // return router ip to use for DestIp (0 if none)
 127 //
 128 STATIC
 129 EFI_IP_ADDRESS *
 130 GetRouterIp (
 131   PXE_BASECODE_DEVICE *Private,
 132   EFI_IP_ADDRESS      *DestIpPtr
 133   )
 134 {
 135   EFI_PXE_BASE_CODE_MODE  *PxeBcMode;
 136   UINTN                   Index;
 137
 138   if (Private == NULL || DestIpPtr == NULL) {
 139     return NULL;
 140   }
 141
 142   PxeBcMode = Private->EfiBc.Mode;
 143
 144   for (Index = 0; Index < PxeBcMode->RouteTableEntries; ++Index) {
 145     if (OnSameSubnet (
 146           Private->IpLength,
 147           &PxeBcMode->RouteTable[Index].IpAddr,
 148           DestIpPtr,
 149           &PxeBcMode->RouteTable[Index].SubnetMask
 150           )) {
 151       return &PxeBcMode->RouteTable[Index].GwAddr;
 152     }
 153   }
 154
 155   return NULL;
 156 }
 157
 158 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 159
 160 //
 161 // routine to send ipv4 packet
 162 // ipv4 header of length HdrLth in TransmitBufferPtr
 163 // routine fills in ipv4hdr Ver_Hdl, TotalLength, and Checksum, moves in Data
 164 // and gets dest MAC address
 165 //
 166 #define IP_TX_BUFFER  ((IPV4_BUFFER *) Private->TransmitBufferPtr)
 167 #define IP_TX_HEADER  IP_TX_BUFFER->IpHeader
 168
 169 EFI_STATUS
 170 Ipv4Xmt (
 171   PXE_BASECODE_DEVICE         *Private,
 172   UINT32                      GatewayIp,
 173   UINTN                       IpHeaderLength,
 174   UINTN                       TotalHeaderLength,
 175   VOID                        *Data,
 176   UINTN                       DataLength,
 177   EFI_PXE_BASE_CODE_FUNCTION  Function
 178   )
 179 {
 180   EFI_MAC_ADDRESS             DestMac;
 181   EFI_SIMPLE_NETWORK_PROTOCOL *Snp;
 182   EFI_PXE_BASE_CODE_MODE      *PxeBcMode;
 183   EFI_STATUS                  StatCode;
 184   UINTN                       PacketLength;
 185
 186   Snp           = Private->SimpleNetwork;
 187   PxeBcMode     = Private->EfiBc.Mode;
 188   StatCode      = EFI_SUCCESS;
 189   PacketLength  = TotalHeaderLength + DataLength;
 190
 191   //
 192   // get dest MAC address
 193   // multicast - convert to hw equiv
 194   // unicast on same net, use arp
 195   // on different net, arp for router
 196   //
 197   if (IP_TX_HEADER.DestAddr.L == BROADCAST_IPv4) {
 198     CopyMem (&DestMac, &Snp->Mode->BroadcastAddress, sizeof (DestMac));
 199   } else if (IS_MULTICAST (&IP_TX_HEADER.DestAddr)) {
 200     StatCode = (*Snp->MCastIpToMac) (Snp, PxeBcMode->UsingIpv6, (EFI_IP_ADDRESS *) &IP_TX_HEADER.DestAddr, &DestMac);
 201   } else {
 202     UINT32  Ip;
 203
 204     if (OnSameSubnet (
 205           Private->IpLength,
 206           &PxeBcMode->StationIp,
 207           (EFI_IP_ADDRESS *) &IP_TX_HEADER.DestAddr,
 208           &PxeBcMode->SubnetMask
 209           )) {
 210       Ip = IP_TX_HEADER.DestAddr.L;
 211     } else if (GatewayIp != 0) {
 212       Ip = GatewayIp;
 213     } else {
 214       EFI_IP_ADDRESS  *TmpIp;
 215
 216       TmpIp = GetRouterIp (Private, (EFI_IP_ADDRESS *) &IP_TX_HEADER.DestAddr);
 217
 218       if (TmpIp == NULL) {
 219         DEBUG (
 220           (EFI_D_WARN,
 221           "\nIpv4Xmit()  Exit #1  %xh (%r)",
 222           EFI_NO_RESPONSE,
 223           EFI_NO_RESPONSE)
 224           );
 225
 226         return EFI_NO_RESPONSE;
 227         //
 228         // no router
 229         //
 230       }
 231
 232       Ip = TmpIp->Addr[0];
 233     }
 234
 235     if (!GetHwAddr (
 236           Private,
 237           (EFI_IP_ADDRESS *) &Ip,
 238           (EFI_MAC_ADDRESS *) &DestMac
 239           )) {
 240       if (!PxeBcMode->AutoArp) {
 241         DEBUG (
 242           (EFI_D_WARN,
 243           "\nIpv4Xmit()  Exit #2  %xh (%r)",
 244           EFI_DEVICE_ERROR,
 245           EFI_DEVICE_ERROR)
 246           );
 247
 248         return EFI_DEVICE_ERROR;
 249       } else {
 250         StatCode = DoArp (
 251                     Private,
 252                     (EFI_IP_ADDRESS *) &Ip,
 253                     (EFI_MAC_ADDRESS *) &DestMac
 254                     );
 255       }
 256     }
 257   }
 258
 259   if (EFI_ERROR (StatCode)) {
 260     DEBUG ((EFI_D_WARN, "\nIpv4Xmit()  Exit #3  %xh (%r)", StatCode, StatCode));
 261     return StatCode;
 262   }
 263   //
 264   // fill in packet info
 265   //
 266   SET_IPV4_VER_HDL (&IP_TX_HEADER, IpHeaderLength);
 267   IP_TX_HEADER.TotalLength    = HTONS (PacketLength);
 268   IP_TX_HEADER.HeaderChecksum = IpChecksum ((UINT16 *) &IP_TX_HEADER, IpHeaderLength);
 269   CopyMem (((UINT8 *) &IP_TX_HEADER) + TotalHeaderLength, Data, DataLength);
 270
 271   //
 272   // send it
 273   //
 274   return SendPacket (
 275           Private,
 276           (UINT8 *) &IP_TX_HEADER - Snp->Mode->MediaHeaderSize,
 277           &IP_TX_HEADER,
 278           PacketLength,
 279           &DestMac,
 280           PXE_PROTOCOL_ETHERNET_IP,
 281           Function
 282           );
 283 }
 284
 285 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 286
 287 //
 288 // send ipv4 packet with option
 289 //
 290 EFI_STATUS
 291 Ipv4SendWOp (
 292   PXE_BASECODE_DEVICE         *Private,
 293   UINT32                      GatewayIp,
 294   UINT8                       *Msg,
 295   UINTN                       MessageLength,
 296   UINT8                       Prot,
 297   UINT8                       *Option,
 298   UINTN                       OptionLength,
 299   UINT32                      DestIp,
 300   EFI_PXE_BASE_CODE_FUNCTION  Function
 301   )
 302 {
 303   EFI_PXE_BASE_CODE_MODE  *PxeBcMode;
 304   UINTN                   HdrLth;
 305
 306   PxeBcMode = Private->EfiBc.Mode;
 307   HdrLth    = sizeof (IPV4_HEADER) + OptionLength;
 308
 309   ZeroMem ((VOID *) &IP_TX_HEADER, sizeof (IPV4_HEADER));
 310   IP_TX_HEADER.TimeToLive     = PxeBcMode->TTL;
 311   IP_TX_HEADER.TypeOfService  = PxeBcMode->ToS;
 312   IP_TX_HEADER.Protocol       = Prot;
 313   IP_TX_HEADER.SrcAddr.L      = *(UINT32 *) &PxeBcMode->StationIp;
 314   IP_TX_HEADER.DestAddr.L     = DestIp;
 315   IP_TX_HEADER.Id             = Random (Private);
 316   CopyMem (IP_TX_BUFFER->u.Data, Option, OptionLength);
 317   return Ipv4Xmt (
 318           Private,
 319           GatewayIp,
 320           HdrLth,
 321           HdrLth,
 322           Msg,
 323           MessageLength,
 324           Function
 325           );
 326 }
 327
 328 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 329
 330 //
 331 // send MessageLength message at MessagePtr - higher level protocol header already in TransmitBufferPtr, length HdrSize
 332 //
 333 EFI_STATUS
 334 Ip4Send (
 335   PXE_BASECODE_DEVICE                          *Private,  // pointer to instance data
 336   UINTN               MayFrag,                            //
 337   UINT8                                    Prot,          // protocol
 338   UINT32                          SrcIp,                  // Source IP address
 339   UINT32                 DestIp,                          // Destination IP address
 340   UINT32              GatewayIp,                          // used if not NULL and needed
 341   UINTN               HdrSize,                            // protocol header byte length
 342   UINT8               *MessagePtr,                        // pointer to data
 343   UINTN               MessageLength                       // data byte length
 344   )
 345 {
 346   EFI_STATUS  StatCode;
 347   UINTN       TotDataLength;
 348
 349   TotDataLength = HdrSize + MessageLength;
 350
 351   if (TotDataLength > MAX_IPV4_DATA_SIZE) {
 352     DEBUG (
 353       (EFI_D_WARN,
 354       "\nIp4Send()  Exit #1  %xh (%r)",
 355       EFI_BAD_BUFFER_SIZE,
 356       EFI_BAD_BUFFER_SIZE)
 357       );
 358
 359     return EFI_BAD_BUFFER_SIZE;
 360   }
 361
 362   ZeroMem ((VOID *) &IP_TX_HEADER, sizeof (IPV4_HEADER));
 363   IP_TX_HEADER.TimeToLive = DEFAULT_TTL;
 364   IP_TX_HEADER.Protocol   = Prot;
 365   IP_TX_HEADER.SrcAddr.L  = SrcIp;
 366   IP_TX_HEADER.DestAddr.L = DestIp;
 367   IP_TX_HEADER.Id         = Random (Private);
 368
 369   if (!MayFrag) {
 370     *(UINT8 *) (&IP_TX_HEADER.FragmentFields) = IP_NO_FRAG >> 8;
 371   }
 372   //
 373   // check for need to fragment
 374   //
 375   if (TotDataLength > MAX_IPV4_FRAME_DATA_SIZE) {
 376     UINTN   DataLengthSent;
 377     UINT16  FragmentOffset;
 378
 379     FragmentOffset = IP_MORE_FRAG;
 380     //
 381     // frag offset field
 382     //
 383     if (!MayFrag) {
 384       DEBUG (
 385         (EFI_D_WARN,
 386         "\nIp4Send()  Exit #2  %xh (%r)",
 387         EFI_BAD_BUFFER_SIZE,
 388         EFI_BAD_BUFFER_SIZE)
 389         );
 390
 391       return EFI_BAD_BUFFER_SIZE;
 392     }
 393     //
 394     // send out in fragments - first includes upper level header
 395     // all are max and include more frag bit except last
 396     //
 397     * (UINT8 *) (&IP_TX_HEADER.FragmentFields) = IP_MORE_FRAG >> 8;
 398
 399 #define IPV4_FRAG_SIZE    (MAX_IPV4_FRAME_DATA_SIZE & 0xfff8)
 400 #define IPV4_FRAG_OFF_INC (IPV4_FRAG_SIZE >> 3)
 401
 402     DataLengthSent = IPV4_FRAG_SIZE - HdrSize;
 403
 404     StatCode = Ipv4Xmt (
 405                 Private,
 406                 GatewayIp,
 407                 sizeof (IPV4_HEADER),
 408                 sizeof (IPV4_HEADER) + HdrSize,
 409                 MessagePtr,
 410                 DataLengthSent,
 411                 Private->Function
 412                 );
 413
 414     if (EFI_ERROR (StatCode)) {
 415       DEBUG (
 416         (EFI_D_WARN,
 417         "\nIp4Send()  Exit #3  %xh (%r)",
 418         StatCode,
 419         StatCode)
 420         );
 421
 422       return StatCode;
 423     }
 424
 425     MessagePtr += DataLengthSent;
 426     MessageLength -= DataLengthSent;
 427     FragmentOffset += IPV4_FRAG_OFF_INC;
 428     IP_TX_HEADER.FragmentFields = HTONS (FragmentOffset);
 429
 430     while (MessageLength > IPV4_FRAG_SIZE) {
 431       StatCode = Ipv4Xmt (
 432                   Private,
 433                   GatewayIp,
 434                   sizeof (IPV4_HEADER),
 435                   sizeof (IPV4_HEADER),
 436                   MessagePtr,
 437                   IPV4_FRAG_SIZE,
 438                   Private->Function
 439                   );
 440
 441       if (EFI_ERROR (StatCode)) {
 442         DEBUG (
 443           (EFI_D_WARN,
 444           "\nIp4Send()  Exit #3  %xh (%r)",
 445           StatCode,
 446           StatCode)
 447           );
 448
 449         return StatCode;
 450       }
 451
 452       MessagePtr += IPV4_FRAG_SIZE;
 453       MessageLength -= IPV4_FRAG_SIZE;
 454       FragmentOffset += IPV4_FRAG_OFF_INC;
 455       IP_TX_HEADER.FragmentFields = HTONS (FragmentOffset);
 456     }
 457
 458     * (UINT8 *) (&IP_TX_HEADER.FragmentFields) &= ~(IP_MORE_FRAG >> 8);
 459     HdrSize = 0;
 460   }
 461   //
 462   // transmit
 463   //
 464   return Ipv4Xmt (
 465           Private,
 466           GatewayIp,
 467           sizeof (IPV4_HEADER),
 468           sizeof (IPV4_HEADER) + HdrSize,
 469           MessagePtr,
 470           MessageLength,
 471           Private->Function
 472           );
 473 }
 474
 475 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 476
 477 //
 478 // return true if dst IP in receive header matched with what's enabled
 479 //
 480 STATIC
 481 BOOLEAN
 482 IPgood (
 483   PXE_BASECODE_DEVICE *Private,
 484   IPV4_HEADER         *IpHeader
 485   )
 486 {
 487   EFI_PXE_BASE_CODE_MODE  *PxeBcMode;
 488   UINTN                   Index;
 489
 490   PxeBcMode = Private->EfiBc.Mode;
 491
 492   if (PxeBcMode->IpFilter.Filters & EFI_PXE_BASE_CODE_IP_FILTER_PROMISCUOUS) {
 493     return TRUE;
 494   }
 495
 496   if ((PxeBcMode->IpFilter.Filters & EFI_PXE_BASE_CODE_IP_FILTER_PROMISCUOUS_MULTICAST) &&
 497       IS_MULTICAST (&IpHeader->DestAddr)
 498         ) {
 499     return TRUE;
 500   }
 501
 502   if ((PxeBcMode->IpFilter.Filters & EFI_PXE_BASE_CODE_IP_FILTER_STATION_IP) &&
 503       PxeBcMode->StationIp.Addr[0] == IpHeader->DestAddr.L
 504       ) {
 505     return TRUE;
 506   }
 507
 508   if ((PxeBcMode->IpFilter.Filters & EFI_PXE_BASE_CODE_IP_FILTER_BROADCAST) && IpHeader->DestAddr.L == BROADCAST_IPv4) {
 509     return TRUE;
 510   }
 511
 512   for (Index = 0; Index < PxeBcMode->IpFilter.IpCnt; ++Index) {
 513     if (IpHeader->DestAddr.L == PxeBcMode->IpFilter.IpList[Index].Addr[0]) {
 514       return TRUE;
 515     }
 516   }
 517
 518   return FALSE;
 519 }
 520
 521 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 522
 523 //
 524 // receive up to MessageLength message into MessagePtr for protocol Prot
 525 // return message length, src/dest ips if select any, and pointer to protocol
 526 // header routine will filter based on source and/or dest ip if OpFlags set.
 527 //
 528 EFI_STATUS
 529 IpReceive (
 530   PXE_BASECODE_DEVICE *Private,
 531   PXE_OPFLAGS         OpFlags,
 532   EFI_IP_ADDRESS      *SrcIpPtr,
 533   EFI_IP_ADDRESS      *DestIpPtr,
 534   UINT8               Prot,
 535   VOID                *HeaderPtr,
 536   UINTN               HdrSize,
 537   UINT8               *MessagePtr,
 538   UINTN               *MessageLengthPtr,
 539   EFI_EVENT           TimeoutEvent
 540   )
 541 {
 542   EFI_PXE_BASE_CODE_MODE  *PxeBcMode;
 543   EFI_STATUS              StatCode;
 544   UINTN                   ByteCount;
 545   UINTN                   FragmentCount;
 546   UINTN                   ExpectedPacketLength;
 547   UINTN                   Id;
 548   BOOLEAN                 GotFirstFragment;
 549   BOOLEAN                 GotLastFragment;
 550
 551   DEBUG (
 552     (EFI_D_NET,
 553     "\nIpReceive()  Hdr=%Xh  HdrSz=%d  Data=%Xh  DataSz=%d",
 554     HeaderPtr,
 555     HdrSize,
 556     MessagePtr,
 557     *MessageLengthPtr)
 558     );
 559
 560   PxeBcMode                     = Private->EfiBc.Mode;
 561   PxeBcMode->IcmpErrorReceived  = FALSE;
 562
 563   ExpectedPacketLength          = 0;
 564   GotFirstFragment              = FALSE;
 565   GotLastFragment               = FALSE;
 566   FragmentCount                 = 0;
 567   ByteCount                     = 0;
 568   Id = 0;
 569
 570   for (;;) {
 571     IPV4_HEADER IpHdr;
 572     UINTN       FFlds;
 573     UINTN       TotalLength;
 574     UINTN       FragmentOffset;
 575     UINTN       HeaderSize;
 576     UINTN       BufferSize;
 577     UINTN       IpHeaderLength;
 578     UINTN       DataLength;
 579     UINT16      Protocol;
 580     UINT8       *NextHdrPtr;
 581     UINT8       *PacketPtr;
 582
 583     StatCode = WaitForReceive (
 584                 Private,
 585                 Private->Function,
 586                 TimeoutEvent,
 587                 &HeaderSize,
 588                 &BufferSize,
 589                 &Protocol
 590                 );
 591
 592     if (EFI_ERROR (StatCode)) {
 593       return StatCode;
 594     }
 595
 596     PacketPtr = Private->ReceiveBufferPtr + HeaderSize;
 597
 598     if (Protocol == PXE_PROTOCOL_ETHERNET_ARP) {
 599       HandleArpReceive (
 600         Private,
 601         (ARP_PACKET *) PacketPtr,
 602         Private->ReceiveBufferPtr
 603         );
 604
 605       continue;
 606     }
 607
 608     if (Protocol != PXE_PROTOCOL_ETHERNET_IP) {
 609       continue;
 610     }
 611
 612 #if SUPPORT_IPV6
 613     if (PxeBcMode->UsingIpv6) {
 614       //
 615       // TBD
 616       //
 617     }
 618 #endif
 619
 620 #define IpRxHeader  ((IPV4_HEADER *) PacketPtr)
 621
 622     //
 623     // filter for version & check sum
 624     //
 625     IpHeaderLength = IPV4_HEADER_LENGTH (IpRxHeader);
 626
 627     if ((IpRxHeader->VersionIhl >> 4) != IPVER4) {
 628       continue;
 629     }
 630
 631     if (IpChecksum ((UINT16 *) IpRxHeader, IpHeaderLength)) {
 632       continue;
 633     }
 634
 635     CopyMem (&IpHdr, IpRxHeader, sizeof (IpHdr));
 636     //IpHdr       = *IpRxHeader;
 637     TotalLength = NTOHS (IpHdr.TotalLength);
 638
 639     if (IpHdr.Protocol == PROT_TCP) {
 640       //
 641       // The NextHdrPtr is used to seed the header buffer we are passing back.
 642       // That being the case, we want to see everything in pPkt which contains
 643       // everything but the ethernet (or whatever) frame.  IP + TCP in this case.
 644       //
 645       DataLength  = TotalLength;
 646       NextHdrPtr  = PacketPtr;
 647     } else {
 648       DataLength  = TotalLength - IpHeaderLength;
 649       NextHdrPtr  = PacketPtr + IpHeaderLength;
 650     }
 651     //
 652     // If this is an ICMP, it might not be for us.
 653     // Double check the state of the IP stack and the
 654     // packet fields before assuming it is an ICMP
 655     // error.  ICMP requests are not supported by the
 656     // PxeBc IP stack and should be ignored.
 657     //
 658     if (IpHdr.Protocol == PROT_ICMP) {
 659       ICMPV4_HEADER *Icmpv4;
 660
 661       Icmpv4 = (ICMPV4_HEADER *) NextHdrPtr;
 662
 663       //
 664       // For now only obvious ICMP error replies will be accepted by
 665       // this stack.  This still makes us vulnerable to DoS attacks.
 666       // But at least we will not be killed by DHCP daemons.
 667       //
 668       switch (Icmpv4->Type) {
 669       case ICMP_REDIRECT:
 670       case ICMP_ECHO:
 671       case ICMP_ROUTER_ADV:
 672       case ICMP_ROUTER_SOLICIT:
 673       case ICMP_TIMESTAMP:
 674       case ICMP_TIMESTAMP_REPLY:
 675       case ICMP_INFO_REQ:
 676       case ICMP_INFO_REQ_REPLY:
 677       case ICMP_SUBNET_MASK_REQ:
 678       case ICMP_SUBNET_MASK_REPLY:
 679       default:
 680         continue;
 681
 682       //
 683       // %%TBD - This should be implemented.
 684       //
 685       case ICMP_ECHO_REPLY:
 686         continue;
 687
 688       case ICMP_DEST_UNREACHABLE:
 689       case ICMP_TIME_EXCEEDED:
 690       case ICMP_PARAMETER_PROBLEM:
 691       case ICMP_SOURCE_QUENCH:
 692         PxeBcMode->IcmpErrorReceived = TRUE;
 693
 694         CopyMem (
 695           &PxeBcMode->IcmpError,
 696           NextHdrPtr,
 697           sizeof (EFI_PXE_BASE_CODE_ICMP_ERROR)
 698           );
 699
 700         DEBUG (
 701           (EFI_D_NET,
 702           "\nIpReceive()  Exit #1  %Xh (%r)",
 703           EFI_ICMP_ERROR,
 704           EFI_ICMP_ERROR)
 705           );
 706       }
 707
 708       return EFI_ICMP_ERROR;
 709     }
 710
 711     if (IpHdr.Protocol == PROT_IGMP) {
 712       HandleIgmp (Private, (IGMPV2_MESSAGE *) NextHdrPtr, DataLength);
 713
 714       DEBUG ((EFI_D_NET, "\n  IGMP"));
 715       continue;
 716     }
 717     //
 718     // check for protocol
 719     //
 720     if (IpHdr.Protocol != Prot) {
 721       continue;
 722     }
 723     //
 724     // do filtering
 725     //
 726     if (!(OpFlags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_SRC_IP) && SrcIpPtr && SrcIpPtr->Addr[0] != IpHdr.SrcAddr.L) {
 727       DEBUG ((EFI_D_NET, "\n  Not expected source IP address."));
 728       continue;
 729     }
 730
 731     if (OpFlags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_USE_FILTER) {
 732       if (!IPgood (Private, &IpHdr)) {
 733         continue;
 734       }
 735     } else if (!(OpFlags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_DEST_IP)) {
 736       if (DestIpPtr == NULL) {
 737         if (PxeBcMode->StationIp.Addr[0] != IpHdr.DestAddr.L) {
 738           continue;
 739         }
 740       } else if (DestIpPtr->Addr[0] != IpHdr.DestAddr.L) {
 741         continue;
 742       }
 743     }
 744     //
 745     // get some data we need
 746     //
 747     FFlds           = NTOHS (IpHdr.FragmentFields);
 748     FragmentOffset  = ((FFlds & IP_FRAG_OFF_MSK) << 3);
 749
 750     /* Keep count of fragments that belong to this session.
 751      * If we get packets with a different IP ID number,
 752      * ignore them.  Ignored packets should be handled
 753      * by the upper level protocol.
 754      */
 755     if (FragmentCount == 0) {
 756       Id = IpHdr.Id;
 757
 758       if (DestIpPtr != NULL) {
 759         DestIpPtr->Addr[0] = IpHdr.DestAddr.L;
 760       }
 761
 762       if (SrcIpPtr != NULL) {
 763         SrcIpPtr->Addr[0] = IpHdr.SrcAddr.L;
 764       }
 765     } else {
 766       if (IpHdr.Id != Id) {
 767         continue;
 768       }
 769     }
 770
 771     ++FragmentCount;
 772
 773     /* Fragment management.
 774      */
 775     if (FragmentOffset == 0) {
 776       /* This is the first fragment (may also be the
 777        * only fragment).
 778        */
 779       GotFirstFragment = TRUE;
 780
 781       /* If there is a separate protocol header buffer,
 782        * copy the header, adjust the data pointer and
 783        * the data length.
 784        */
 785       if (HdrSize != 0) {
 786         CopyMem (HeaderPtr, NextHdrPtr, HdrSize);
 787
 788         NextHdrPtr += HdrSize;
 789         DataLength -= HdrSize;
 790       }
 791     } else {
 792       /* If there is a separate protocol header buffer,
 793        * adjust the fragment offset.
 794        */
 795       FragmentOffset -= HdrSize;
 796     }
 797
 798     /* See if this is the last fragment.
 799      */
 800     if (!(FFlds & IP_MORE_FRAG)) {
 801       //
 802       // This is the last fragment (may also be the only fragment).
 803       //
 804       GotLastFragment = TRUE;
 805
 806       /* Compute the expected length of the assembled
 807        * packet.  This will be used to decide if we
 808        * have gotten all of the fragments.
 809        */
 810       ExpectedPacketLength = FragmentOffset + DataLength;
 811     }
 812
 813     DEBUG (
 814       (EFI_D_NET,
 815       "\n  ID = %Xh  Off = %d  Len = %d",
 816       Id,
 817       FragmentOffset,
 818       DataLength)
 819       );
 820
 821     /* Check for receive buffer overflow.
 822      */
 823     if (FragmentOffset + DataLength > *MessageLengthPtr) {
 824       /* There is not enough space in the receive
 825        * buffer for the fragment.
 826        */
 827       DEBUG (
 828         (EFI_D_NET,
 829         "\nIpReceive()  Exit #3  %Xh (%r)",
 830         EFI_BUFFER_TOO_SMALL,
 831         EFI_BUFFER_TOO_SMALL)
 832         );
 833
 834       return EFI_BUFFER_TOO_SMALL;
 835     }
 836
 837     /* Copy data into receive buffer.
 838      */
 839     if (DataLength != 0) {
 840       DEBUG ((EFI_D_NET, "  To = %Xh", MessagePtr + FragmentOffset));
 841
 842       CopyMem (MessagePtr + FragmentOffset, NextHdrPtr, DataLength);
 843       ByteCount += DataLength;
 844     }
 845
 846     /* If we have seen the first and last fragments and
 847      * the receive byte count is at least as large as the
 848      * expected byte count, return SUCCESS.
 849      *
 850      * We could be tricked by receiving a fragment twice
 851      * but the upper level protocol should figure this
 852      * out.
 853      */
 854     if (GotFirstFragment && GotLastFragment && ByteCount >= ExpectedPacketLength) {
 855       *MessageLengthPtr = ExpectedPacketLength;
 856       return EFI_SUCCESS;
 857     }
 858   }
 859 }
 860
 861 /* eof - pxe_bc_ip.c */