reactos/lib/drivers/ip/network/receive.c

   1 /*
   2  * COPYRIGHT:   See COPYING in the top level directory
   3  * PROJECT:     ReactOS TCP/IP protocol driver
   4  * FILE:        network/receive.c
   5  * PURPOSE:     Internet Protocol receive routines
   6  * PROGRAMMERS: Casper S. Hornstrup (chorns@users.sourceforge.net)
   7  * NOTES:       The IP datagram reassembly algorithm is taken from
   8  *              from RFC 815
   9  * REVISIONS:
  10  *   CSH 01/08-2000 Created
  11  */
  12
  13 #include "precomp.h"
  14
  15 LIST_ENTRY ReassemblyListHead;
  16 KSPIN_LOCK ReassemblyListLock;
  17 NPAGED_LOOKASIDE_LIST IPDRList;
  18 NPAGED_LOOKASIDE_LIST IPFragmentList;
  19 NPAGED_LOOKASIDE_LIST IPHoleList;
  20
  21 PIPDATAGRAM_HOLE CreateHoleDescriptor(
  22   ULONG First,
  23   ULONG Last)
  24 /*
  25  * FUNCTION: Returns a pointer to a IP datagram hole descriptor
  26  * ARGUMENTS:
  27  *     First = Offset of first octet of the hole
  28  *     Last  = Offset of last octet of the hole
  29  * RETURNS:
  30  *     Pointer to descriptor, NULL if there was not enough free
  31  *     resources
  32  */
  33 {
  34         PIPDATAGRAM_HOLE Hole;
  35
  36         TI_DbgPrint(DEBUG_IP, ("Called. First (%d)  Last (%d).\n", First, Last));
  37
  38         Hole = ExAllocateFromNPagedLookasideList(&IPHoleList);
  39         if (!Hole) {
  40             TI_DbgPrint(MIN_TRACE, ("Insufficient resources.\n"));
  41             return NULL;
  42         }
  43
  44         Hole->First = First;
  45         Hole->Last  = Last;
  46
  47         TI_DbgPrint(DEBUG_IP, ("Returning hole descriptor at (0x%X).\n", Hole));
  48
  49         return Hole;
  50 }
  51
  52
  53 VOID FreeIPDR(
  54   PIPDATAGRAM_REASSEMBLY IPDR)
  55 /*
  56  * FUNCTION: Frees an IP datagram reassembly structure
  57  * ARGUMENTS:
  58  *     IPDR = Pointer to IP datagram reassembly structure
  59  */
  60 {
  61   PLIST_ENTRY CurrentEntry;
  62   PLIST_ENTRY NextEntry;
  63   PIPDATAGRAM_HOLE CurrentH;
  64   PIP_FRAGMENT CurrentF;
  65
  66   TI_DbgPrint(DEBUG_IP, ("Freeing IP datagram reassembly descriptor (0x%X).\n", IPDR));
  67
  68   /* Free all descriptors */
  69   CurrentEntry = IPDR->HoleListHead.Flink;
  70   while (CurrentEntry != &IPDR->HoleListHead) {
  71     NextEntry = CurrentEntry->Flink;
  72           CurrentH = CONTAINING_RECORD(CurrentEntry, IPDATAGRAM_HOLE, ListEntry);
  73     /* Unlink it from the list */
  74     RemoveEntryList(CurrentEntry);
  75
  76     TI_DbgPrint(DEBUG_IP, ("Freeing hole descriptor at (0x%X).\n", CurrentH));
  77
  78     /* And free the hole descriptor */
  79     ExFreeToNPagedLookasideList(&IPHoleList, CurrentH);
  80
  81     CurrentEntry = NextEntry;
  82   }
  83
  84   /* Free all fragments */
  85   CurrentEntry = IPDR->FragmentListHead.Flink;
  86   while (CurrentEntry != &IPDR->FragmentListHead) {
  87     NextEntry = CurrentEntry->Flink;
  88           CurrentF = CONTAINING_RECORD(CurrentEntry, IP_FRAGMENT, ListEntry);
  89     /* Unlink it from the list */
  90     RemoveEntryList(CurrentEntry);
  91
  92     TI_DbgPrint(DEBUG_IP, ("Freeing fragment data at (0x%X).\n", CurrentF->Data));
  93
  94     /* Free the fragment data buffer */
  95     ExFreePoolWithTag(CurrentF->Data, FRAGMENT_DATA_TAG);
  96
  97     TI_DbgPrint(DEBUG_IP, ("Freeing fragment at (0x%X).\n", CurrentF));
  98
  99     /* And free the fragment descriptor */
 100     ExFreeToNPagedLookasideList(&IPFragmentList, CurrentF);
 101     CurrentEntry = NextEntry;
 102   }
 103
 104   TI_DbgPrint(DEBUG_IP, ("Freeing IPDR data at (0x%X).\n", IPDR));
 105
 106   ExFreeToNPagedLookasideList(&IPDRList, IPDR);
 107 }
 108
 109
 110 VOID RemoveIPDR(
 111   PIPDATAGRAM_REASSEMBLY IPDR)
 112 /*
 113  * FUNCTION: Removes an IP datagram reassembly structure from the global list
 114  * ARGUMENTS:
 115  *     IPDR = Pointer to IP datagram reassembly structure
 116  */
 117 {
 118   KIRQL OldIrql;
 119
 120   TI_DbgPrint(DEBUG_IP, ("Removing IPDR at (0x%X).\n", IPDR));
 121
 122   TcpipAcquireSpinLock(&ReassemblyListLock, &OldIrql);
 123   RemoveEntryList(&IPDR->ListEntry);
 124   TcpipReleaseSpinLock(&ReassemblyListLock, OldIrql);
 125 }
 126
 127
 128 PIPDATAGRAM_REASSEMBLY GetReassemblyInfo(
 129   PIP_PACKET IPPacket)
 130 /*
 131  * FUNCTION: Returns a pointer to an IP datagram reassembly structure
 132  * ARGUMENTS:
 133  *     IPPacket = Pointer to IP packet
 134  * NOTES:
 135  *     A datagram is identified by four paramters, which are
 136  *     Source and destination address, protocol number and
 137  *     identification number
 138  */
 139 {
 140   KIRQL OldIrql;
 141   PLIST_ENTRY CurrentEntry;
 142   PIPDATAGRAM_REASSEMBLY Current;
 143   PIPv4_HEADER Header = (PIPv4_HEADER)IPPacket->Header;
 144
 145   TI_DbgPrint(DEBUG_IP, ("Searching for IPDR for IP packet at (0x%X).\n", IPPacket));
 146
 147   TcpipAcquireSpinLock(&ReassemblyListLock, &OldIrql);
 148
 149   /* FIXME: Assume IPv4 */
 150
 151   CurrentEntry = ReassemblyListHead.Flink;
 152   while (CurrentEntry != &ReassemblyListHead) {
 153           Current = CONTAINING_RECORD(CurrentEntry, IPDATAGRAM_REASSEMBLY, ListEntry);
 154     if (AddrIsEqual(&IPPacket->SrcAddr, &Current->SrcAddr) &&
 155       (Header->Id == Current->Id) &&
 156       (Header->Protocol == Current->Protocol) &&
 157       (AddrIsEqual(&IPPacket->DstAddr, &Current->DstAddr))) {
 158       TcpipReleaseSpinLock(&ReassemblyListLock, OldIrql);
 159
 160       return Current;
 161     }
 162     CurrentEntry = CurrentEntry->Flink;
 163   }
 164
 165   TcpipReleaseSpinLock(&ReassemblyListLock, OldIrql);
 166
 167   return NULL;
 168 }
 169
 170
 171 BOOLEAN
 172 ReassembleDatagram(
 173   PIP_PACKET             IPPacket,
 174   PIPDATAGRAM_REASSEMBLY IPDR)
 175 /*
 176  * FUNCTION: Reassembles an IP datagram
 177  * ARGUMENTS:
 178  *     IPDR = Pointer to IP datagram reassembly structure
 179  * NOTES:
 180  *     This routine concatenates fragments into a complete IP datagram.
 181  *     The lock is held when this routine is called
 182  * RETURNS:
 183  *     Pointer to IP packet, NULL if there was not enough free resources
 184  * NOTES:
 185  *     At this point, header is expected to point to the IP header
 186  */
 187 {
 188   PLIST_ENTRY CurrentEntry;
 189   PIP_FRAGMENT Current;
 190   PVOID Data;
 191
 192   TI_DbgPrint(DEBUG_IP, ("Reassembling datagram from IPDR at (0x%X).\n", IPDR));
 193   TI_DbgPrint(DEBUG_IP, ("IPDR->HeaderSize = %d\n", IPDR->HeaderSize));
 194   TI_DbgPrint(DEBUG_IP, ("IPDR->DataSize = %d\n", IPDR->DataSize));
 195
 196   TI_DbgPrint(DEBUG_IP, ("Fragment header:\n"));
 197   //OskitDumpBuffer((PCHAR)IPDR->IPv4Header, IPDR->HeaderSize);
 198
 199   IPPacket->TotalSize  = IPDR->HeaderSize + IPDR->DataSize;
 200   IPPacket->ContigSize = IPPacket->TotalSize;
 201   IPPacket->HeaderSize = IPDR->HeaderSize;
 202   /*IPPacket->Position   = IPDR->HeaderSize;*/
 203
 204   RtlCopyMemory(&IPPacket->SrcAddr, &IPDR->SrcAddr, sizeof(IP_ADDRESS));
 205   RtlCopyMemory(&IPPacket->DstAddr, &IPDR->DstAddr, sizeof(IP_ADDRESS));
 206
 207   /* Allocate space for full IP datagram */
 208   IPPacket->Header = ExAllocatePoolWithTag(NonPagedPool, IPPacket->TotalSize, PACKET_BUFFER_TAG);
 209   if (!IPPacket->Header) {
 210     TI_DbgPrint(MIN_TRACE, ("Insufficient resources.\n"));
 211     (*IPPacket->Free)(IPPacket);
 212     return FALSE;
 213   }
 214
 215   /* Copy the header into the buffer */
 216   RtlCopyMemory(IPPacket->Header, &IPDR->IPv4Header, IPDR->HeaderSize);
 217
 218   Data = (PVOID)((ULONG_PTR)IPPacket->Header + IPDR->HeaderSize);
 219   IPPacket->Data = Data;
 220
 221   /* Copy data from all fragments into buffer */
 222   CurrentEntry = IPDR->FragmentListHead.Flink;
 223   while (CurrentEntry != &IPDR->FragmentListHead) {
 224     Current = CONTAINING_RECORD(CurrentEntry, IP_FRAGMENT, ListEntry);
 225
 226     TI_DbgPrint(DEBUG_IP, ("Copying (%d) bytes of fragment data from (0x%X) to offset (%d).\n",
 227       Current->Size, Data, Current->Offset));
 228     /* Copy fragment data to the destination buffer at the correct offset */
 229     RtlCopyMemory((PVOID)((ULONG_PTR)Data + Current->Offset),
 230                   Current->Data,
 231                   Current->Size);
 232     //OskitDumpBuffer( Data, Current->Offset + Current->Size );
 233     CurrentEntry = CurrentEntry->Flink;
 234   }
 235
 236   return TRUE;
 237 }
 238
 239
 240 __inline VOID Cleanup(
 241   PKSPIN_LOCK Lock,
 242   KIRQL OldIrql,
 243   PIPDATAGRAM_REASSEMBLY IPDR)
 244 /*
 245  * FUNCTION: Performs cleaning operations on errors
 246  * ARGUMENTS:
 247  *     Lock     = Pointer to spin lock to be released
 248  *     OldIrql  = Value of IRQL when spin lock was acquired
 249  *     IPDR     = Pointer to IP datagram reassembly structure to free
 250  *     Buffer   = Optional pointer to a buffer to free
 251  */
 252 {
 253   TI_DbgPrint(MIN_TRACE, ("Insufficient resources.\n"));
 254
 255   TcpipReleaseSpinLock(Lock, OldIrql);
 256   RemoveIPDR(IPDR);
 257   FreeIPDR(IPDR);
 258 }
 259
 260
 261 VOID ProcessFragment(
 262   PIP_INTERFACE IF,
 263   PIP_PACKET IPPacket)
 264 /*
 265  * FUNCTION: Processes an IP datagram or fragment
 266  * ARGUMENTS:
 267  *     IF       = Pointer to IP interface packet was receive on
 268  *     IPPacket = Pointer to IP packet
 269  * NOTES:
 270  *     This routine reassembles fragments and, if a whole datagram can
 271  *     be assembled, passes the datagram on to the IP protocol dispatcher
 272  */
 273 {
 274   KIRQL OldIrql;
 275   PIPDATAGRAM_REASSEMBLY IPDR;
 276   PLIST_ENTRY CurrentEntry;
 277   PIPDATAGRAM_HOLE Hole, NewHole;
 278   USHORT FragFirst;
 279   USHORT FragLast;
 280   BOOLEAN MoreFragments;
 281   PIPv4_HEADER IPv4Header;
 282   IP_PACKET Datagram;
 283   PIP_FRAGMENT Fragment;
 284   BOOLEAN Success;
 285
 286   /* FIXME: Assume IPv4 */
 287
 288   IPv4Header = (PIPv4_HEADER)IPPacket->Header;
 289
 290   /* Check if we already have an reassembly structure for this datagram */
 291   IPDR = GetReassemblyInfo(IPPacket);
 292   if (IPDR) {
 293     TI_DbgPrint(DEBUG_IP, ("Continueing assembly.\n"));
 294     /* We have a reassembly structure */
 295     TcpipAcquireSpinLock(&IPDR->Lock, &OldIrql);
 296   } else {
 297     TI_DbgPrint(DEBUG_IP, ("Starting new assembly.\n"));
 298
 299     /* We don't have a reassembly structure, create one */
 300     IPDR = ExAllocateFromNPagedLookasideList(&IPDRList);
 301     if (!IPDR)
 302       /* We don't have the resources to process this packet, discard it */
 303       return;
 304
 305     /* Create a descriptor spanning from zero to infinity.
 306        Actually, we use a value slightly greater than the
 307        maximum number of octets an IP datagram can contain */
 308     Hole = CreateHoleDescriptor(0, 65536);
 309     if (!Hole) {
 310       /* We don't have the resources to process this packet, discard it */
 311       ExFreeToNPagedLookasideList(&IPDRList, IPDR);
 312       return;
 313     }
 314     AddrInitIPv4(&IPDR->SrcAddr, IPv4Header->SrcAddr);
 315     AddrInitIPv4(&IPDR->DstAddr, IPv4Header->DstAddr);
 316     IPDR->Id         = IPv4Header->Id;
 317     IPDR->Protocol   = IPv4Header->Protocol;
 318     IPDR->TimeoutCount = 0;
 319     InitializeListHead(&IPDR->FragmentListHead);
 320     InitializeListHead(&IPDR->HoleListHead);
 321     InsertTailList(&IPDR->HoleListHead, &Hole->ListEntry);
 322
 323     TcpipInitializeSpinLock(&IPDR->Lock);
 324
 325     TcpipAcquireSpinLock(&IPDR->Lock, &OldIrql);
 326
 327     /* Update the reassembly list */
 328     TcpipInterlockedInsertTailList(
 329         &ReassemblyListHead,
 330         &IPDR->ListEntry,
 331         &ReassemblyListLock);
 332   }
 333
 334   FragFirst     = (WN2H(IPv4Header->FlagsFragOfs) & IPv4_FRAGOFS_MASK) << 3;
 335   FragLast      = FragFirst + WN2H(IPv4Header->TotalLength);
 336   MoreFragments = (WN2H(IPv4Header->FlagsFragOfs) & IPv4_MF_MASK) > 0;
 337
 338   CurrentEntry = IPDR->HoleListHead.Flink;
 339   for (;;) {
 340     if (CurrentEntry == &IPDR->HoleListHead)
 341         break;
 342
 343     Hole = CONTAINING_RECORD(CurrentEntry, IPDATAGRAM_HOLE, ListEntry);
 344
 345     TI_DbgPrint(DEBUG_IP, ("Comparing Fragment (%d,%d) to Hole (%d,%d).\n",
 346       FragFirst, FragLast, Hole->First, Hole->Last));
 347
 348     if ((FragFirst > Hole->Last) || (FragLast < Hole->First)) {
 349       TI_DbgPrint(MID_TRACE, ("No overlap.\n"));
 350       /* The fragment does not overlap with the hole, try next
 351          descriptor in the list */
 352
 353       CurrentEntry = CurrentEntry->Flink;
 354       continue;
 355     }
 356
 357     /* The fragment overlap with the hole, unlink the descriptor */
 358     RemoveEntryList(CurrentEntry);
 359
 360     if (FragFirst > Hole->First) {
 361       NewHole = CreateHoleDescriptor(Hole->First, FragFirst - 1);
 362       if (!NewHole) {
 363         /* We don't have the resources to process this packet, discard it */
 364         ExFreeToNPagedLookasideList(&IPHoleList, Hole);
 365         Cleanup(&IPDR->Lock, OldIrql, IPDR);
 366         return;
 367       }
 368
 369       /* Put the new descriptor in the list */
 370       InsertTailList(&IPDR->HoleListHead, &NewHole->ListEntry);
 371     }
 372
 373     if ((FragLast < Hole->Last) && MoreFragments) {
 374       NewHole = CreateHoleDescriptor(FragLast + 1, Hole->Last);
 375       if (!NewHole) {
 376         /* We don't have the resources to process this packet, discard it */
 377         ExFreeToNPagedLookasideList(&IPHoleList, Hole);
 378         Cleanup(&IPDR->Lock, OldIrql, IPDR);
 379         return;
 380       }
 381
 382       /* Put the new hole descriptor in the list */
 383       InsertTailList(&IPDR->HoleListHead, &NewHole->ListEntry);
 384     }
 385
 386     ExFreeToNPagedLookasideList(&IPHoleList, Hole);
 387
 388     /* If this is the first fragment, save the IP header */
 389     if (FragFirst == 0) {
 390       TI_DbgPrint(DEBUG_IP, ("First fragment found. Header buffer is at (0x%X). "
 391         "Header size is (%d).\n", &IPDR->IPv4Header, IPPacket->HeaderSize));
 392
 393       RtlCopyMemory(&IPDR->IPv4Header, IPPacket->Header, IPPacket->HeaderSize);
 394       IPDR->HeaderSize = IPPacket->HeaderSize;
 395     }
 396
 397     /* Create a buffer, copy the data into it and put it
 398        in the fragment list */
 399
 400     Fragment = ExAllocateFromNPagedLookasideList(&IPFragmentList);
 401     if (!Fragment) {
 402       /* We don't have the resources to process this packet, discard it */
 403       Cleanup(&IPDR->Lock, OldIrql, IPDR);
 404       return;
 405     }
 406
 407     TI_DbgPrint(DEBUG_IP, ("Fragment descriptor allocated at (0x%X).\n", Fragment));
 408
 409     Fragment->Size = IPPacket->TotalSize - IPPacket->HeaderSize;
 410     Fragment->Data = ExAllocatePoolWithTag(NonPagedPool, Fragment->Size, FRAGMENT_DATA_TAG);
 411     if (!Fragment->Data) {
 412       /* We don't have the resources to process this packet, discard it */
 413       ExFreeToNPagedLookasideList(&IPFragmentList, Fragment);
 414       Cleanup(&IPDR->Lock, OldIrql, IPDR);
 415       return;
 416     }
 417
 418     /* Position here is an offset from the NdisPacket start, not the header */
 419     TI_DbgPrint(DEBUG_IP, ("Fragment data buffer allocated at (0x%X)  Size (%d) Pos (%d).\n",
 420                            Fragment->Data, Fragment->Size, IPPacket->Position));
 421
 422     /* Copy datagram data into fragment buffer */
 423     CopyPacketToBuffer(Fragment->Data,
 424                        IPPacket->NdisPacket,
 425                        IPPacket->HeaderSize,
 426                        Fragment->Size);
 427     Fragment->Offset = FragFirst;
 428
 429     /* If this is the last fragment, compute and save the datagram data size */
 430     if (!MoreFragments)
 431       IPDR->DataSize = FragFirst + Fragment->Size;
 432
 433     /* Put the fragment in the list */
 434     InsertTailList(&IPDR->FragmentListHead, &Fragment->ListEntry);
 435     break;
 436   }
 437
 438   TI_DbgPrint(DEBUG_IP, ("Done searching for hole descriptor.\n"));
 439
 440   if (IsListEmpty(&IPDR->HoleListHead)) {
 441     /* Hole list is empty which means a complete datagram can be assembled.
 442        Assemble the datagram and pass it to an upper layer protocol */
 443
 444     TI_DbgPrint(DEBUG_IP, ("Complete datagram received.\n"));
 445
 446     /* FIXME: Assumes IPv4 */
 447     IPInitializePacket(&Datagram, IP_ADDRESS_V4);
 448
 449     Success = ReassembleDatagram(&Datagram, IPDR);
 450
 451     RemoveIPDR(IPDR);
 452     TcpipReleaseSpinLock(&IPDR->Lock, OldIrql);
 453
 454     FreeIPDR(IPDR);
 455
 456     if (!Success)
 457       /* Not enough free resources, discard the packet */
 458       return;
 459
 460     DISPLAY_IP_PACKET(&Datagram);
 461
 462     /* Give the packet to the protocol dispatcher */
 463     IPDispatchProtocol(IF, &Datagram);
 464
 465     IF->Stats.InBytes += Datagram.TotalSize;
 466
 467     /* We're done with this datagram */
 468     ExFreePoolWithTag(Datagram.Header, PACKET_BUFFER_TAG);
 469     TI_DbgPrint(MAX_TRACE, ("Freeing datagram at (0x%X).\n", Datagram));
 470     (*Datagram.Free)(&Datagram);
 471   } else
 472     TcpipReleaseSpinLock(&IPDR->Lock, OldIrql);
 473 }
 474
 475
 476 VOID IPFreeReassemblyList(
 477   VOID)
 478 /*
 479  * FUNCTION: Frees all IP datagram reassembly structures in the list
 480  */
 481 {
 482   KIRQL OldIrql;
 483   PLIST_ENTRY CurrentEntry;
 484   PIPDATAGRAM_REASSEMBLY Current;
 485
 486   TcpipAcquireSpinLock(&ReassemblyListLock, &OldIrql);
 487
 488   CurrentEntry = ReassemblyListHead.Flink;
 489   while (CurrentEntry != &ReassemblyListHead) {
 490           Current = CONTAINING_RECORD(CurrentEntry, IPDATAGRAM_REASSEMBLY, ListEntry);
 491     /* Unlink it from the list */
 492     RemoveEntryList(CurrentEntry);
 493
 494     /* And free the descriptor */
 495     FreeIPDR(Current);
 496
 497     CurrentEntry = CurrentEntry->Flink;
 498   }
 499
 500   TcpipReleaseSpinLock(&ReassemblyListLock, OldIrql);
 501 }
 502
 503
 504 VOID IPDatagramReassemblyTimeout(
 505   VOID)
 506 /*
 507  * FUNCTION: IP datagram reassembly timeout handler
 508  * NOTES:
 509  *     This routine is called by IPTimeout to free any resources used
 510  *     to hold IP fragments that have taken too long to reassemble
 511  */
 512 {
 513     PLIST_ENTRY CurrentEntry, NextEntry;
 514     PIPDATAGRAM_REASSEMBLY CurrentIPDR;
 515
 516     TcpipAcquireSpinLockAtDpcLevel(&ReassemblyListLock);
 517
 518     CurrentEntry = ReassemblyListHead.Flink;
 519     while (CurrentEntry != &ReassemblyListHead)
 520     {
 521        NextEntry = CurrentEntry->Flink;
 522        CurrentIPDR = CONTAINING_RECORD(CurrentEntry, IPDATAGRAM_REASSEMBLY, ListEntry);
 523
 524        TcpipAcquireSpinLockAtDpcLevel(&CurrentIPDR->Lock);
 525
 526        if (++CurrentIPDR->TimeoutCount == MAX_TIMEOUT_COUNT)
 527        {
 528            TcpipReleaseSpinLockFromDpcLevel(&CurrentIPDR->Lock);
 529            RemoveEntryList(CurrentEntry);
 530            FreeIPDR(CurrentIPDR);
 531        }
 532        else
 533        {
 534            ASSERT(CurrentIPDR->TimeoutCount < MAX_TIMEOUT_COUNT);
 535            TcpipReleaseSpinLockFromDpcLevel(&CurrentIPDR->Lock);
 536        }
 537
 538        CurrentEntry = NextEntry;
 539     }
 540
 541     TcpipReleaseSpinLockFromDpcLevel(&ReassemblyListLock);
 542 }
 543
 544 VOID IPv4Receive(PIP_INTERFACE IF, PIP_PACKET IPPacket)
 545 /*
 546  * FUNCTION: Receives an IPv4 datagram (or fragment)
 547  * ARGUMENTS:
 548  *     Context  = Pointer to context information (IP_INTERFACE)
 549  *     IPPacket = Pointer to IP packet
 550  */
 551 {
 552     TI_DbgPrint(DEBUG_IP, ("Received IPv4 datagram.\n"));
 553
 554     IPPacket->HeaderSize = (((PIPv4_HEADER)IPPacket->Header)->VerIHL & 0x0F) << 2;
 555     TI_DbgPrint(DEBUG_IP, ("IPPacket->HeaderSize = %d\n", IPPacket->HeaderSize));
 556
 557     if (IPPacket->HeaderSize > IPv4_MAX_HEADER_SIZE) {
 558         TI_DbgPrint
 559             (MIN_TRACE,
 560              ("Datagram received with incorrect header size (%d).\n",
 561               IPPacket->HeaderSize));
 562         /* Discard packet */
 563         return;
 564     }
 565
 566     /* Checksum IPv4 header */
 567     if (!IPv4CorrectChecksum(IPPacket->Header, IPPacket->HeaderSize)) {
 568         TI_DbgPrint
 569             (MIN_TRACE,
 570              ("Datagram received with bad checksum. Checksum field (0x%X)\n",
 571               WN2H(((PIPv4_HEADER)IPPacket->Header)->Checksum)));
 572         /* Discard packet */
 573         return;
 574     }
 575
 576     IPPacket->TotalSize = WN2H(((PIPv4_HEADER)IPPacket->Header)->TotalLength);
 577
 578     AddrInitIPv4(&IPPacket->SrcAddr, ((PIPv4_HEADER)IPPacket->Header)->SrcAddr);
 579     AddrInitIPv4(&IPPacket->DstAddr, ((PIPv4_HEADER)IPPacket->Header)->DstAddr);
 580
 581     IPPacket->Position += IPPacket->HeaderSize;
 582     IPPacket->Data     = (PVOID)((ULONG_PTR)IPPacket->Header + IPPacket->HeaderSize);
 583
 584     TI_DbgPrint(MID_TRACE,("IPPacket->Position = %d\n",
 585                            IPPacket->Position));
 586
 587     //OskitDumpBuffer(IPPacket->Header, IPPacket->TotalSize);
 588
 589     /* FIXME: Possibly forward packets with multicast addresses */
 590
 591     /* FIXME: Should we allow packets to be received on the wrong interface? */
 592     /* XXX Find out if this packet is destined for us */
 593     ProcessFragment(IF, IPPacket);
 594 #if 0
 595     } else {
 596         /* This packet is not destined for us. If we are a router,
 597            try to find a route and forward the packet */
 598
 599         /* FIXME: Check if acting as a router */
 600         NCE = NULL;
 601         if (NCE) {
 602             PROUTE_CACHE_NODE RCN;
 603
 604             /* FIXME: Possibly fragment datagram */
 605             /* Forward the packet */
 606             if(!RouteGetRouteToDestination( &IPPacket->DstAddr, NULL, &RCN ))
 607                 IPSendDatagram(IPPacket, RCN, ReflectPacketComplete, IPPacket);
 608         } else {
 609             TI_DbgPrint(MIN_TRACE, ("No route to destination (0x%X).\n",
 610                                     IPPacket->DstAddr.Address.IPv4Address));
 611
 612             /* FIXME: Send ICMP error code */
 613         }
 614     }
 615 #endif
 616 }
 617
 618
 619 VOID IPReceive( PIP_INTERFACE IF, PIP_PACKET IPPacket )
 620 /*
 621  * FUNCTION: Receives an IP datagram (or fragment)
 622  * ARGUMENTS:
 623  *     IF       = Interface
 624  *     IPPacket = Pointer to IP packet
 625  */
 626 {
 627   UINT Version;
 628
 629   /* Check that IP header has a supported version */
 630   Version = (((PIPv4_HEADER)IPPacket->Header)->VerIHL >> 4);
 631
 632   switch (Version) {
 633   case 4:
 634     IPPacket->Type = IP_ADDRESS_V4;
 635     IPv4Receive(IF, IPPacket);
 636     break;
 637   case 6:
 638     IPPacket->Type = IP_ADDRESS_V6;
 639     TI_DbgPrint(MAX_TRACE, ("Datagram of type IPv6 discarded.\n"));
 640     break;
 641   default:
 642           TI_DbgPrint(MIN_TRACE, ("Datagram has an unsupported IP version %d.\n", Version));
 643     break;
 644   }
 645
 646   IPPacket->Free(IPPacket);
 647 }
 648
 649 /* EOF */