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

   1 /*
   2  * COPYRIGHT:   See COPYING in the top level directory
   3  * PROJECT:     ReactOS TCP/IP protocol driver
   4  * FILE:        network/router.c
   5  * PURPOSE:     IP routing subsystem
   6  * PROGRAMMERS: Casper S. Hornstrup (chorns@users.sourceforge.net)
   7  * NOTES:
   8  *   This file holds authoritative routing information.
   9  *   Information queries on the route table should be handled here.
  10  *   This information should always override the route cache info.
  11  * REVISIONS:
  12  *   CSH 01/08-2000 Created
  13  */
  14
  15 #include "precomp.h"
  16
  17
  18 LIST_ENTRY FIBListHead;
  19 KSPIN_LOCK FIBLock;
  20
  21 void RouterDumpRoutes() {
  22     PLIST_ENTRY CurrentEntry;
  23     PLIST_ENTRY NextEntry;
  24     PFIB_ENTRY Current;
  25     PNEIGHBOR_CACHE_ENTRY NCE;
  26
  27     TI_DbgPrint(DEBUG_ROUTER,("Dumping Routes\n"));
  28
  29     CurrentEntry = FIBListHead.Flink;
  30     while (CurrentEntry != &FIBListHead) {
  31         NextEntry = CurrentEntry->Flink;
  32         Current = CONTAINING_RECORD(CurrentEntry, FIB_ENTRY, ListEntry);
  33
  34         NCE   = Current->Router;
  35
  36         TI_DbgPrint(DEBUG_ROUTER,("Examining FIBE %x\n", Current));
  37         TI_DbgPrint(DEBUG_ROUTER,("... NetworkAddress %s\n", A2S(&Current->NetworkAddress)));
  38         TI_DbgPrint(DEBUG_ROUTER,("... NCE->Address . %s\n", A2S(&NCE->Address)));
  39
  40         CurrentEntry = NextEntry;
  41     }
  42
  43     TI_DbgPrint(DEBUG_ROUTER,("Dumping Routes ... Done\n"));
  44 }
  45
  46 VOID FreeFIB(
  47     PVOID Object)
  48 /*
  49  * FUNCTION: Frees an forward information base object
  50  * ARGUMENTS:
  51  *     Object = Pointer to an forward information base structure
  52  */
  53 {
  54     exFreePool(Object);
  55 }
  56
  57
  58 VOID DestroyFIBE(
  59     PFIB_ENTRY FIBE)
  60 /*
  61  * FUNCTION: Destroys an forward information base entry
  62  * ARGUMENTS:
  63  *     FIBE = Pointer to FIB entry
  64  * NOTES:
  65  *     The forward information base lock must be held when called
  66  */
  67 {
  68     TI_DbgPrint(DEBUG_ROUTER, ("Called. FIBE (0x%X).\n", FIBE));
  69
  70     /* Unlink the FIB entry from the list */
  71     RemoveEntryList(&FIBE->ListEntry);
  72
  73     /* And free the FIB entry */
  74     FreeFIB(FIBE);
  75 }
  76
  77
  78 VOID DestroyFIBEs(
  79     VOID)
  80 /*
  81  * FUNCTION: Destroys all forward information base entries
  82  * NOTES:
  83  *     The forward information base lock must be held when called
  84  */
  85 {
  86     PLIST_ENTRY CurrentEntry;
  87     PLIST_ENTRY NextEntry;
  88     PFIB_ENTRY Current;
  89
  90     /* Search the list and remove every FIB entry we find */
  91     CurrentEntry = FIBListHead.Flink;
  92     while (CurrentEntry != &FIBListHead) {
  93         NextEntry = CurrentEntry->Flink;
  94         Current = CONTAINING_RECORD(CurrentEntry, FIB_ENTRY, ListEntry);
  95         /* Destroy the FIB entry */
  96         DestroyFIBE(Current);
  97         CurrentEntry = NextEntry;
  98     }
  99 }
 100
 101
 102 UINT CountFIBs() {
 103     UINT FibCount = 0;
 104     PLIST_ENTRY CurrentEntry;
 105     PLIST_ENTRY NextEntry;
 106
 107     /* Search the list and remove every FIB entry we find */
 108     CurrentEntry = FIBListHead.Flink;
 109     while (CurrentEntry != &FIBListHead) {
 110         NextEntry = CurrentEntry->Flink;
 111         CurrentEntry = NextEntry;
 112         FibCount++;
 113     }
 114
 115     return FibCount;
 116 }
 117
 118
 119 UINT CopyFIBs( PFIB_ENTRY Target ) {
 120     UINT FibCount = 0;
 121     PLIST_ENTRY CurrentEntry;
 122     PLIST_ENTRY NextEntry;
 123     PFIB_ENTRY Current;
 124
 125     /* Search the list and remove every FIB entry we find */
 126     CurrentEntry = FIBListHead.Flink;
 127     while (CurrentEntry != &FIBListHead) {
 128         NextEntry = CurrentEntry->Flink;
 129         Current = CONTAINING_RECORD(CurrentEntry, FIB_ENTRY, ListEntry);
 130         Target[FibCount] = *Current;
 131         CurrentEntry = NextEntry;
 132         FibCount++;
 133     }
 134
 135     return FibCount;
 136 }
 137
 138
 139 UINT CommonPrefixLength(
 140     PIP_ADDRESS Address1,
 141     PIP_ADDRESS Address2)
 142 /*
 143  * FUNCTION: Computes the length of the longest prefix common to two addresses
 144  * ARGUMENTS:
 145  *     Address1 = Pointer to first address
 146  *     Address2 = Pointer to second address
 147  * NOTES:
 148  *     The two addresses must be of the same type
 149  * RETURNS:
 150  *     Length of longest common prefix
 151  */
 152 {
 153     PUCHAR Addr1, Addr2;
 154     UINT Size;
 155     UINT i, j;
 156     UINT Bitmask;
 157
 158     TI_DbgPrint(DEBUG_ROUTER, ("Called. Address1 (0x%X)  Address2 (0x%X).\n", Address1, Address2));
 159
 160     /*TI_DbgPrint(DEBUG_ROUTER, ("Target  (%s) \n", A2S(Address1)));*/
 161     /*TI_DbgPrint(DEBUG_ROUTER, ("Adapter (%s).\n", A2S(Address2)));*/
 162
 163     if (Address1->Type == IP_ADDRESS_V4)
 164         Size = sizeof(IPv4_RAW_ADDRESS);
 165     else
 166         Size = sizeof(IPv6_RAW_ADDRESS);
 167
 168     Addr1 = (PUCHAR)&Address1->Address.IPv4Address;
 169     Addr2 = (PUCHAR)&Address2->Address.IPv4Address;
 170
 171     /* Find first non-matching byte */
 172     for (i = 0; i < Size && Addr1[i] == Addr2[i]; i++);
 173     if( i == Size ) return 8 * i;
 174
 175     /* Find first non-matching bit */
 176     Bitmask = 0x80;
 177     for (j = 0; (Addr1[i] & Bitmask) == (Addr2[i] & Bitmask); j++)
 178         Bitmask >>= 1;
 179
 180     TI_DbgPrint(DEBUG_ROUTER, ("Returning %d\n", 8 * i + j));
 181
 182     return 8 * i + j;
 183 }
 184
 185
 186 PFIB_ENTRY RouterAddRoute(
 187     PIP_ADDRESS NetworkAddress,
 188     PIP_ADDRESS Netmask,
 189     PNEIGHBOR_CACHE_ENTRY Router,
 190     UINT Metric)
 191 /*
 192  * FUNCTION: Adds a route to the Forward Information Base (FIB)
 193  * ARGUMENTS:
 194  *     NetworkAddress = Pointer to address of network
 195  *     Netmask        = Pointer to netmask of network
 196  *     Router         = Pointer to NCE of router to use
 197  *     Metric         = Cost of this route
 198  * RETURNS:
 199  *     Pointer to FIB entry if the route was added, NULL if not
 200  * NOTES:
 201  *     The FIB entry references the NetworkAddress, Netmask and
 202  *     the NCE of the router. The caller is responsible for providing
 203  *     these references
 204  */
 205 {
 206     PFIB_ENTRY FIBE;
 207
 208     TI_DbgPrint(DEBUG_ROUTER, ("Called. NetworkAddress (0x%X)  Netmask (0x%X) "
 209         "Router (0x%X)  Metric (%d).\n", NetworkAddress, Netmask, Router, Metric));
 210
 211     TI_DbgPrint(DEBUG_ROUTER, ("NetworkAddress (%s)  Netmask (%s)  Router (%s).\n",
 212                                A2S(NetworkAddress),
 213                                A2S(Netmask),
 214                                A2S(&Router->Address)));
 215
 216     FIBE = exAllocatePool(NonPagedPool, sizeof(FIB_ENTRY));
 217     if (!FIBE) {
 218         TI_DbgPrint(MIN_TRACE, ("Insufficient resources.\n"));
 219         return NULL;
 220     }
 221
 222     INIT_TAG(Router, 'TUOR');
 223
 224     RtlCopyMemory( &FIBE->NetworkAddress, NetworkAddress,
 225                    sizeof(FIBE->NetworkAddress) );
 226     RtlCopyMemory( &FIBE->Netmask, Netmask,
 227                    sizeof(FIBE->Netmask) );
 228     FIBE->Router         = Router;
 229     FIBE->Metric         = Metric;
 230
 231     /* Add FIB to the forward information base */
 232     TcpipInterlockedInsertTailList(&FIBListHead, &FIBE->ListEntry, &FIBLock);
 233
 234     return FIBE;
 235 }
 236
 237
 238 PNEIGHBOR_CACHE_ENTRY RouterGetRoute(PIP_ADDRESS Destination)
 239 /*
 240  * FUNCTION: Finds a router to use to get to Destination
 241  * ARGUMENTS:
 242  *     Destination = Pointer to destination address (NULL means don't care)
 243  * RETURNS:
 244  *     Pointer to NCE for router, NULL if none was found
 245  * NOTES:
 246  *     If found the NCE is referenced
 247  */
 248 {
 249     KIRQL OldIrql;
 250     PLIST_ENTRY CurrentEntry;
 251     PLIST_ENTRY NextEntry;
 252     PFIB_ENTRY Current;
 253     UCHAR State, BestState = 0;
 254     UINT Length, BestLength = 0, MaskLength;
 255     PNEIGHBOR_CACHE_ENTRY NCE, BestNCE = NULL;
 256
 257     TI_DbgPrint(DEBUG_ROUTER, ("Called. Destination (0x%X)\n", Destination));
 258
 259     TI_DbgPrint(DEBUG_ROUTER, ("Destination (%s)\n", A2S(Destination)));
 260
 261     TcpipAcquireSpinLock(&FIBLock, &OldIrql);
 262
 263     CurrentEntry = FIBListHead.Flink;
 264     while (CurrentEntry != &FIBListHead) {
 265         NextEntry = CurrentEntry->Flink;
 266             Current = CONTAINING_RECORD(CurrentEntry, FIB_ENTRY, ListEntry);
 267
 268         NCE   = Current->Router;
 269         State = NCE->State;
 270
 271         Length = CommonPrefixLength(Destination, &Current->NetworkAddress);
 272         MaskLength = AddrCountPrefixBits(&Current->Netmask);
 273
 274         TI_DbgPrint(DEBUG_ROUTER,("This-Route: %s (Sharing %d bits)\n",
 275                                   A2S(&NCE->Address), Length));
 276
 277         if(Length >= MaskLength && (Length > BestLength || !BestNCE) &&
 278            (!(State & NUD_STALE) || !BestNCE)) {
 279             /* This seems to be a better router */
 280             BestNCE    = NCE;
 281             BestLength = Length;
 282             BestState  = State;
 283             TI_DbgPrint(DEBUG_ROUTER,("Route selected\n"));
 284         }
 285
 286         CurrentEntry = NextEntry;
 287     }
 288
 289     TcpipReleaseSpinLock(&FIBLock, OldIrql);
 290
 291     if( BestNCE ) {
 292         TI_DbgPrint(DEBUG_ROUTER,("Routing to %s\n", A2S(&BestNCE->Address)));
 293     } else {
 294         TI_DbgPrint(DEBUG_ROUTER,("Packet won't be routed\n"));
 295     }
 296
 297     return BestNCE;
 298 }
 299
 300 PNEIGHBOR_CACHE_ENTRY RouteGetRouteToDestination(PIP_ADDRESS Destination)
 301 /*
 302  * FUNCTION: Locates an RCN describing a route to a destination address
 303  * ARGUMENTS:
 304  *     Destination = Pointer to destination address to find route to
 305  *     RCN         = Address of pointer to an RCN
 306  * RETURNS:
 307  *     Status of operation
 308  * NOTES:
 309  *     The RCN is referenced for the caller. The caller is responsible
 310  *     for dereferencing it after use
 311  */
 312 {
 313     PNEIGHBOR_CACHE_ENTRY NCE = NULL;
 314     PIP_INTERFACE Interface;
 315
 316     TI_DbgPrint(DEBUG_RCACHE, ("Called. Destination (0x%X)\n", Destination));
 317
 318     TI_DbgPrint(DEBUG_RCACHE, ("Destination (%s)\n", A2S(Destination)));
 319
 320 #if 0
 321     TI_DbgPrint(MIN_TRACE, ("Displaying tree (before).\n"));
 322     PrintTree(RouteCache);
 323 #endif
 324
 325     /* Check if the destination is on-link */
 326     Interface = FindOnLinkInterface(Destination);
 327     if (Interface) {
 328         /* The destination address is on-link. Check our neighbor cache */
 329         NCE = NBFindOrCreateNeighbor(Interface, Destination);
 330     } else {
 331         /* Destination is not on any subnets we're on. Find a router to use */
 332         NCE = RouterGetRoute(Destination);
 333     }
 334
 335     if( NCE )
 336         TI_DbgPrint(DEBUG_ROUTER,("Interface->MTU: %d\n", NCE->Interface->MTU));
 337
 338     return NCE;
 339 }
 340
 341 NTSTATUS RouterRemoveRoute(PIP_ADDRESS Target, PIP_ADDRESS Router)
 342 /*
 343  * FUNCTION: Removes a route from the Forward Information Base (FIB)
 344  * ARGUMENTS:
 345  *     Target: The machine or network targeted by the route
 346  *     Router: The router used to pass the packet to the destination
 347  *
 348  * Searches the FIB and removes a route matching the indicated parameters.
 349  */
 350 {
 351     KIRQL OldIrql;
 352     PLIST_ENTRY CurrentEntry;
 353     PLIST_ENTRY NextEntry;
 354     PFIB_ENTRY Current;
 355     BOOLEAN Found = FALSE;
 356     PNEIGHBOR_CACHE_ENTRY NCE;
 357
 358     TI_DbgPrint(DEBUG_ROUTER, ("Called\n"));
 359     TI_DbgPrint(DEBUG_ROUTER, ("Deleting Route From: %s\n", A2S(Router)));
 360     TI_DbgPrint(DEBUG_ROUTER, ("                 To: %s\n", A2S(Target)));
 361
 362     TcpipAcquireSpinLock(&FIBLock, &OldIrql);
 363
 364     RouterDumpRoutes();
 365
 366     CurrentEntry = FIBListHead.Flink;
 367     while (CurrentEntry != &FIBListHead) {
 368         NextEntry = CurrentEntry->Flink;
 369         Current = CONTAINING_RECORD(CurrentEntry, FIB_ENTRY, ListEntry);
 370
 371         NCE   = Current->Router;
 372
 373         if( AddrIsEqual( &Current->NetworkAddress, Target ) &&
 374             AddrIsEqual( &NCE->Address, Router ) ) {
 375             Found = TRUE;
 376             break;
 377         }
 378
 379         Current = NULL;
 380         CurrentEntry = NextEntry;
 381     }
 382
 383     if( Found ) {
 384         TI_DbgPrint(DEBUG_ROUTER, ("Deleting route\n"));
 385         DestroyFIBE( Current );
 386     }
 387
 388     RouterDumpRoutes();
 389
 390     TcpipReleaseSpinLock(&FIBLock, OldIrql);
 391
 392     TI_DbgPrint(DEBUG_ROUTER, ("Leaving\n"));
 393
 394     return Found ? STATUS_SUCCESS : STATUS_UNSUCCESSFUL;
 395 }
 396
 397
 398 PFIB_ENTRY RouterCreateRoute(
 399     PIP_ADDRESS NetworkAddress,
 400     PIP_ADDRESS Netmask,
 401     PIP_ADDRESS RouterAddress,
 402     PIP_INTERFACE Interface,
 403     UINT Metric)
 404 /*
 405  * FUNCTION: Creates a route with IPv4 addresses as parameters
 406  * ARGUMENTS:
 407  *     NetworkAddress = Address of network
 408  *     Netmask        = Netmask of network
 409  *     RouterAddress  = Address of router to use
 410  *     NTE            = Pointer to NTE to use
 411  *     Metric         = Cost of this route
 412  * RETURNS:
 413  *     Pointer to FIB entry if the route was created, NULL if not.
 414  *     The FIB entry references the NTE. The caller is responsible
 415  *     for providing this reference
 416  */
 417 {
 418     KIRQL OldIrql;
 419     PLIST_ENTRY CurrentEntry;
 420     PLIST_ENTRY NextEntry;
 421     PFIB_ENTRY Current;
 422     PNEIGHBOR_CACHE_ENTRY NCE;
 423
 424     TcpipAcquireSpinLock(&FIBLock, &OldIrql);
 425
 426     CurrentEntry = FIBListHead.Flink;
 427     while (CurrentEntry != &FIBListHead) {
 428         NextEntry = CurrentEntry->Flink;
 429         Current = CONTAINING_RECORD(CurrentEntry, FIB_ENTRY, ListEntry);
 430
 431         NCE   = Current->Router;
 432
 433         if( AddrIsEqual(NetworkAddress, &Current->NetworkAddress) &&
 434             AddrIsEqual(Netmask, &Current->Netmask) ) {
 435             TI_DbgPrint(DEBUG_ROUTER,("Attempting to add duplicate route to %s\n", A2S(NetworkAddress)));
 436             TcpipReleaseSpinLock(&FIBLock, OldIrql);
 437             return NULL;
 438         }
 439
 440         CurrentEntry = NextEntry;
 441     }
 442
 443     TcpipReleaseSpinLock(&FIBLock, OldIrql);
 444
 445     /* The NCE references RouterAddress. The NCE is referenced for us */
 446     NCE = NBFindOrCreateNeighbor(Interface, RouterAddress);
 447
 448     if (!NCE) {
 449         /* Not enough free resources */
 450         return NULL;
 451     }
 452
 453     return RouterAddRoute(NetworkAddress, Netmask, NCE, Metric);
 454 }
 455
 456
 457 NTSTATUS RouterStartup(
 458     VOID)
 459 /*
 460  * FUNCTION: Initializes the routing subsystem
 461  * RETURNS:
 462  *     Status of operation
 463  */
 464 {
 465     TI_DbgPrint(DEBUG_ROUTER, ("Called.\n"));
 466
 467     /* Initialize the Forward Information Base */
 468     InitializeListHead(&FIBListHead);
 469     TcpipInitializeSpinLock(&FIBLock);
 470
 471     return STATUS_SUCCESS;
 472 }
 473
 474
 475 NTSTATUS RouterShutdown(
 476     VOID)
 477 /*
 478  * FUNCTION: Shuts down the routing subsystem
 479  * RETURNS:
 480  *     Status of operation
 481  */
 482 {
 483     KIRQL OldIrql;
 484
 485     TI_DbgPrint(DEBUG_ROUTER, ("Called.\n"));
 486
 487     /* Clear Forward Information Base */
 488     TcpipAcquireSpinLock(&FIBLock, &OldIrql);
 489     DestroyFIBEs();
 490     TcpipReleaseSpinLock(&FIBLock, OldIrql);
 491
 492     return STATUS_SUCCESS;
 493 }
 494
 495 /* EOF */