reactos/drivers/lib/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
  22 VOID FreeFIB(
  23     PVOID Object)
  24 /*
  25  * FUNCTION: Frees an forward information base object
  26  * ARGUMENTS:
  27  *     Object = Pointer to an forward information base structure
  28  */
  29 {
  30     PoolFreeBuffer(Object);
  31 }
  32
  33
  34 VOID DestroyFIBE(
  35     PFIB_ENTRY FIBE)
  36 /*
  37  * FUNCTION: Destroys an forward information base entry
  38  * ARGUMENTS:
  39  *     FIBE = Pointer to FIB entry
  40  * NOTES:
  41  *     The forward information base lock must be held when called
  42  */
  43 {
  44     TI_DbgPrint(DEBUG_ROUTER, ("Called. FIBE (0x%X).\n", FIBE));
  45
  46     /* Unlink the FIB entry from the list */
  47     RemoveEntryList(&FIBE->ListEntry);
  48
  49     /* And free the FIB entry */
  50     FreeFIB(FIBE);
  51 }
  52
  53
  54 VOID DestroyFIBEs(
  55     VOID)
  56 /*
  57  * FUNCTION: Destroys all forward information base entries
  58  * NOTES:
  59  *     The forward information base lock must be held when called
  60  */
  61 {
  62     PLIST_ENTRY CurrentEntry;
  63     PLIST_ENTRY NextEntry;
  64     PFIB_ENTRY Current;
  65
  66     /* Search the list and remove every FIB entry we find */
  67     CurrentEntry = FIBListHead.Flink;
  68     while (CurrentEntry != &FIBListHead) {
  69         NextEntry = CurrentEntry->Flink;
  70         Current = CONTAINING_RECORD(CurrentEntry, FIB_ENTRY, ListEntry);
  71         /* Destroy the FIB entry */
  72         DestroyFIBE(Current);
  73         CurrentEntry = NextEntry;
  74     }
  75 }
  76
  77
  78 UINT CountFIBs() {
  79     UINT FibCount = 0;
  80     PLIST_ENTRY CurrentEntry;
  81     PLIST_ENTRY NextEntry;
  82
  83     /* Search the list and remove every FIB entry we find */
  84     CurrentEntry = FIBListHead.Flink;
  85     while (CurrentEntry != &FIBListHead) {
  86         NextEntry = CurrentEntry->Flink;
  87         CurrentEntry = NextEntry;
  88         FibCount++;
  89     }
  90
  91     return FibCount;
  92 }
  93
  94
  95 UINT CopyFIBs( PFIB_ENTRY Target ) {
  96     UINT FibCount = 0;
  97     PLIST_ENTRY CurrentEntry;
  98     PLIST_ENTRY NextEntry;
  99     PFIB_ENTRY Current;
 100
 101     /* Search the list and remove every FIB entry we find */
 102     CurrentEntry = FIBListHead.Flink;
 103     while (CurrentEntry != &FIBListHead) {
 104         NextEntry = CurrentEntry->Flink;
 105         Current = CONTAINING_RECORD(CurrentEntry, FIB_ENTRY, ListEntry);
 106         Target[FibCount] = *Current;
 107         CurrentEntry = NextEntry;
 108         FibCount++;
 109     }
 110
 111     return FibCount;
 112 }
 113
 114
 115 UINT CommonPrefixLength(
 116     PIP_ADDRESS Address1,
 117     PIP_ADDRESS Address2)
 118 /*
 119  * FUNCTION: Computes the length of the longest prefix common to two addresses
 120  * ARGUMENTS:
 121  *     Address1 = Pointer to first address
 122  *     Address2 = Pointer to second address
 123  * NOTES:
 124  *     The two addresses must be of the same type
 125  * RETURNS:
 126  *     Length of longest common prefix
 127  */
 128 {
 129     PUCHAR Addr1, Addr2;
 130     UINT Size;
 131     UINT i, j;
 132     UINT Bitmask;
 133
 134     TI_DbgPrint(DEBUG_ROUTER, ("Called. Address1 (0x%X)  Address2 (0x%X).\n", Address1, Address2));
 135
 136     /*TI_DbgPrint(DEBUG_ROUTER, ("Target  (%s) \n", A2S(Address1)));*/
 137     /*TI_DbgPrint(DEBUG_ROUTER, ("Adapter (%s).\n", A2S(Address2)));*/
 138
 139     if (Address1->Type == IP_ADDRESS_V4)
 140         Size = sizeof(IPv4_RAW_ADDRESS);
 141     else
 142         Size = sizeof(IPv6_RAW_ADDRESS);
 143
 144     Addr1 = (PUCHAR)&Address1->Address.IPv4Address;
 145     Addr2 = (PUCHAR)&Address2->Address.IPv4Address;
 146
 147     /* Find first non-matching byte */
 148     for (i = 0; i < Size && Addr1[i] == Addr2[i]; i++);
 149     if( i == Size ) return 8 * i;
 150
 151     /* Find first non-matching bit */
 152     Bitmask = 0x80;
 153     for (j = 0; (Addr1[i] & Bitmask) == (Addr2[i] & Bitmask); j++)
 154         Bitmask >>= 1;
 155
 156     TI_DbgPrint(DEBUG_ROUTER, ("Returning %d\n", 8 * i + j));
 157
 158     return 8 * i + j;
 159 }
 160
 161
 162 PFIB_ENTRY RouterAddRoute(
 163     PIP_ADDRESS NetworkAddress,
 164     PIP_ADDRESS Netmask,
 165     PNEIGHBOR_CACHE_ENTRY Router,
 166     UINT Metric)
 167 /*
 168  * FUNCTION: Adds a route to the Forward Information Base (FIB)
 169  * ARGUMENTS:
 170  *     NetworkAddress = Pointer to address of network
 171  *     Netmask        = Pointer to netmask of network
 172  *     Router         = Pointer to NCE of router to use
 173  *     Metric         = Cost of this route
 174  * RETURNS:
 175  *     Pointer to FIB entry if the route was added, NULL if not
 176  * NOTES:
 177  *     The FIB entry references the NetworkAddress, Netmask and
 178  *     the NCE of the router. The caller is responsible for providing
 179  *     these references
 180  */
 181 {
 182     PFIB_ENTRY FIBE;
 183
 184     TI_DbgPrint(DEBUG_ROUTER, ("Called. NetworkAddress (0x%X)  Netmask (0x%X) "
 185         "Router (0x%X)  Metric (%d).\n", NetworkAddress, Netmask, Router, Metric));
 186
 187     TI_DbgPrint(DEBUG_ROUTER, ("NetworkAddress (%s)  Netmask (%s)  Router (%s).\n",
 188                                A2S(NetworkAddress),
 189                                A2S(Netmask),
 190                                A2S(&Router->Address)));
 191
 192     FIBE = PoolAllocateBuffer(sizeof(FIB_ENTRY));
 193     if (!FIBE) {
 194         TI_DbgPrint(MIN_TRACE, ("Insufficient resources.\n"));
 195         return NULL;
 196     }
 197
 198    INIT_TAG(Router, TAG('R','O','U','T'));
 199
 200     RtlCopyMemory( &FIBE->NetworkAddress, NetworkAddress,
 201                    sizeof(FIBE->NetworkAddress) );
 202     RtlCopyMemory( &FIBE->Netmask, Netmask,
 203                    sizeof(FIBE->Netmask) );
 204     FIBE->Router         = Router;
 205     FIBE->Metric         = Metric;
 206
 207     /* Add FIB to the forward information base */
 208     TcpipInterlockedInsertTailList(&FIBListHead, &FIBE->ListEntry, &FIBLock);
 209
 210     return FIBE;
 211 }
 212
 213
 214 PNEIGHBOR_CACHE_ENTRY RouterGetRoute(PIP_ADDRESS Destination)
 215 /*
 216  * FUNCTION: Finds a router to use to get to Destination
 217  * ARGUMENTS:
 218  *     Destination = Pointer to destination address (NULL means don't care)
 219  * RETURNS:
 220  *     Pointer to NCE for router, NULL if none was found
 221  * NOTES:
 222  *     If found the NCE is referenced
 223  */
 224 {
 225     KIRQL OldIrql;
 226     PLIST_ENTRY CurrentEntry;
 227     PLIST_ENTRY NextEntry;
 228     PFIB_ENTRY Current;
 229     UCHAR State, BestState = 0;
 230     UINT Length, BestLength = 0;
 231     PNEIGHBOR_CACHE_ENTRY NCE, BestNCE = NULL;
 232
 233     TI_DbgPrint(DEBUG_ROUTER, ("Called. Destination (0x%X)\n", Destination));
 234
 235     TI_DbgPrint(DEBUG_ROUTER, ("Destination (%s)\n", A2S(Destination)));
 236
 237     TcpipAcquireSpinLock(&FIBLock, &OldIrql);
 238
 239     CurrentEntry = FIBListHead.Flink;
 240     while (CurrentEntry != &FIBListHead) {
 241         NextEntry = CurrentEntry->Flink;
 242             Current = CONTAINING_RECORD(CurrentEntry, FIB_ENTRY, ListEntry);
 243
 244         NCE   = Current->Router;
 245         State = NCE->State;
 246
 247         if (Destination)
 248             Length = CommonPrefixLength(Destination, &NCE->Address);
 249         else
 250             Length = 0;
 251
 252         if (BestNCE) {
 253             if ((State  > BestState)  ||
 254                 ((State == BestState) &&
 255                  (Length > BestLength))) {
 256                 /* This seems to be a better router */
 257                 BestNCE    = NCE;
 258                 BestLength = Length;
 259                 BestState  = State;
 260             }
 261         } else {
 262             /* First suitable router found, save it */
 263             BestNCE    = NCE;
 264             BestLength = Length;
 265             BestState  = State;
 266         }
 267
 268         CurrentEntry = NextEntry;
 269     }
 270
 271     TcpipReleaseSpinLock(&FIBLock, OldIrql);
 272
 273     return BestNCE;
 274 }
 275
 276
 277 VOID RouterRemoveRoute(
 278     PFIB_ENTRY FIBE)
 279 /*
 280  * FUNCTION: Removes a route from the Forward Information Base (FIB)
 281  * ARGUMENTS:
 282  *     FIBE = Pointer to FIB entry describing route
 283  */
 284 {
 285     KIRQL OldIrql;
 286
 287     TI_DbgPrint(DEBUG_ROUTER, ("Called. FIBE (0x%X).\n", FIBE));
 288
 289     TI_DbgPrint(DEBUG_ROUTER, ("FIBE (%s).\n", A2S(&FIBE->NetworkAddress)));
 290
 291     TcpipAcquireSpinLock(&FIBLock, &OldIrql);
 292     DestroyFIBE(FIBE);
 293     TcpipReleaseSpinLock(&FIBLock, OldIrql);
 294 }
 295
 296
 297 PFIB_ENTRY RouterCreateRoute(
 298     IP_ADDRESS NetworkAddress,
 299     IP_ADDRESS Netmask,
 300     IP_ADDRESS RouterAddress,
 301     PIP_INTERFACE Interface,
 302     UINT Metric)
 303 /*
 304  * FUNCTION: Creates a route with IPv4 addresses as parameters
 305  * ARGUMENTS:
 306  *     NetworkAddress = Address of network
 307  *     Netmask        = Netmask of network
 308  *     RouterAddress  = Address of router to use
 309  *     NTE            = Pointer to NTE to use
 310  *     Metric         = Cost of this route
 311  * RETURNS:
 312  *     Pointer to FIB entry if the route was created, NULL if not.
 313  *     The FIB entry references the NTE. The caller is responsible
 314  *     for providing this reference
 315  */
 316 {
 317     PNEIGHBOR_CACHE_ENTRY NCE;
 318     PFIB_ENTRY FIBE;
 319
 320     /* The NCE references RouterAddress. The NCE is referenced for us */
 321     NCE = NBAddNeighbor(Interface,
 322                         &RouterAddress,
 323                         NULL,
 324                         Interface->AddressLength,
 325                         NUD_PROBE);
 326     if (!NCE) {
 327         /* Not enough free resources */
 328         return NULL;
 329     }
 330
 331     FIBE = RouterAddRoute(&NetworkAddress, &Netmask, NCE, 1);
 332     if (!FIBE) {
 333         /* Not enough free resources */
 334         NBRemoveNeighbor(NCE);
 335     }
 336
 337     return FIBE;
 338 }
 339
 340
 341 NTSTATUS RouterStartup(
 342     VOID)
 343 /*
 344  * FUNCTION: Initializes the routing subsystem
 345  * RETURNS:
 346  *     Status of operation
 347  */
 348 {
 349     TI_DbgPrint(DEBUG_ROUTER, ("Called.\n"));
 350
 351     /* Initialize the Forward Information Base */
 352     InitializeListHead(&FIBListHead);
 353     TcpipInitializeSpinLock(&FIBLock);
 354
 355 #if 0
 356     /* TEST: Create a test route */
 357     /* Network is 10.0.0.0  */
 358     /* Netmask is 255.0.0.0 */
 359     /* Router is 10.0.0.1   */
 360     RouterCreateRouteIPv4(0x0000000A, 0x000000FF, 0x0100000A, NTE?, 1);
 361 #endif
 362     return STATUS_SUCCESS;
 363 }
 364
 365
 366 NTSTATUS RouterShutdown(
 367     VOID)
 368 /*
 369  * FUNCTION: Shuts down the routing subsystem
 370  * RETURNS:
 371  *     Status of operation
 372  */
 373 {
 374     KIRQL OldIrql;
 375
 376     TI_DbgPrint(DEBUG_ROUTER, ("Called.\n"));
 377
 378     /* Clear Forward Information Base */
 379     TcpipAcquireSpinLock(&FIBLock, &OldIrql);
 380     DestroyFIBEs();
 381     TcpipReleaseSpinLock(&FIBLock, OldIrql);
 382
 383     return STATUS_SUCCESS;
 384 }
 385
 386 /* EOF */