KernelLand/Modules/IPStack/arp.c

   1 /*
   2  * Acess2 IP Stack
   3  * - Address Resolution Protocol
   4  * - Part of the IPv4 protocol
   5  */
   6 #define DEBUG   0
   7 #include "ipstack.h"
   8 #include "arp.h"
   9 #include "link.h"
  10 #include "ipv4.h"       // For IPv4_Netmask
  11 #include "include/adapters_int.h"       // for MAC addr
  12 #include <semaphore.h>
  13 #include <timers.h>
  14
  15 #define ARPv6   0
  16 #define ARP_CACHE_SIZE  128
  17 #define ARP_MAX_AGE             (60*60*1000)    // 1Hr
  18
  19 // === IMPORTS ===
  20 extern tInterface       *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast);
  21 #if ARPv6
  22 extern tInterface       *IPv6_GetInterface(tAdapter *Adapter, tIPv6 Address, int Broadcast);
  23 #endif
  24
  25 // === PROTOTYPES ===
  26  int    ARP_Initialise();
  27 tMacAddr        ARP_Resolve4(tInterface *Interface, tIPv4 Address);
  28 void    ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer);
  29
  30 // === GLOBALS ===
  31 struct sARP_Cache4 {
  32         tIPv4   IP;
  33         tMacAddr        MAC;
  34         Sint64  LastUpdate;
  35         Sint64  LastUsed;
  36 }       *gaARP_Cache4;
  37  int    giARP_Cache4Space;
  38 tMutex  glARP_Cache4;
  39 tSemaphore      gARP_Cache4Semaphore;
  40  int    giARP_WaitingThreads;
  41 #if ARPv6
  42 struct sARP_Cache6 {
  43         tIPv6   IP;
  44         tMacAddr        MAC;
  45         Sint64  LastUpdate;
  46         Sint64  LastUsed;
  47 }       *gaARP_Cache6;
  48  int    giARP_Cache6Space;
  49 tMutex  glARP_Cache6;
  50 #endif
  51
  52 // === CODE ===
  53 /**
  54  * \fn int ARP_Initialise()
  55  * \brief Initalise the ARP section
  56  */
  57 int ARP_Initialise()
  58 {
  59         gaARP_Cache4 = malloc( ARP_CACHE_SIZE * sizeof(struct sARP_Cache4) );
  60         memset( gaARP_Cache4, 0, ARP_CACHE_SIZE * sizeof(struct sARP_Cache4) );
  61         giARP_Cache4Space = ARP_CACHE_SIZE;
  62
  63         #if ARPv6
  64         gaARP_Cache6 = malloc( ARP_CACHE_SIZE * sizeof(struct sARP_Cache6) );
  65         memset( gaARP_Cache6, 0, ARP_CACHE_SIZE * sizeof(struct sARP_Cache6) );
  66         giARP_Cache6Space = ARP_CACHE_SIZE;
  67         #endif
  68
  69         Link_RegisterType(0x0806, ARP_int_GetPacket);
  70         Semaphore_Init(&gARP_Cache4Semaphore, 0, 0, "ARP4", "Cache Changes");
  71         return 1;
  72 }
  73
  74 /**
  75  * \brief Resolves a MAC address from an IPv4 address
  76  */
  77 tMacAddr ARP_Resolve4(tInterface *Interface, tIPv4 Address)
  78 {
  79          int    i;
  80         struct sArpRequest4     req;
  81
  82         ENTER("pInterface xAddress", Interface, Address);
  83
  84         // Check for broadcast
  85         if( Address.L == -1 )
  86         {
  87                 LOG("Broadcast");
  88                 LEAVE('-');
  89                 return cMAC_BROADCAST;
  90         }
  91
  92         // Check routing tables if not on this subnet
  93         if( IPStack_CompareAddress(4, &Address, Interface->Address, Interface->SubnetBits) == 0 )
  94         {
  95                 tRoute  *route = IPStack_FindRoute(4, Interface, &Address);
  96                 // If the next hop is defined, use it
  97                 // - 0.0.0.0 as the next hop means "no next hop / direct"
  98                 if( route && ((tIPv4*)route->NextHop)->L != 0 )
  99                 {
 100                         // Recursion: see /Recursion/
 101                         LOG("Recursing with %s", IPStack_PrintAddress(4, route->NextHop));
 102                         LEAVE('-');
 103                         return ARP_Resolve4(Interface, *(tIPv4*)route->NextHop);
 104                 }
 105                 // No route, fall though
 106         }
 107         else
 108         {
 109                 Uint32  netmask;
 110                 // Check for broadcast
 111                 netmask = IPv4_Netmask(Interface->SubnetBits);
 112                 if( (Address.L & ~netmask) == (0xFFFFFFFF & ~netmask) )
 113                 {
 114                         LOG("Local Broadcast");
 115                         LEAVE('-');
 116                         return cMAC_BROADCAST;
 117                 }
 118         }
 119
 120         // Check ARP Cache
 121         Mutex_Acquire( &glARP_Cache4 );
 122         for( i = 0; i < giARP_Cache4Space; i++ )
 123         {
 124                 if(gaARP_Cache4[i].IP.L != Address.L)   continue;
 125
 126                 // Check if the entry needs to be refreshed
 127                 if( now() - gaARP_Cache4[i].LastUpdate > ARP_MAX_AGE )  break;
 128
 129                 Mutex_Release( &glARP_Cache4 );
 130                 LOG("Return %x:%x:%x:%x:%x:%x",
 131                         gaARP_Cache4[i].MAC.B[0], gaARP_Cache4[i].MAC.B[1],
 132                         gaARP_Cache4[i].MAC.B[2], gaARP_Cache4[i].MAC.B[3],
 133                         gaARP_Cache4[i].MAC.B[4], gaARP_Cache4[i].MAC.B[5]
 134                         );
 135                 LEAVE('-');
 136                 return gaARP_Cache4[i].MAC;
 137         }
 138         giARP_WaitingThreads ++;
 139         Mutex_Release( &glARP_Cache4 );
 140
 141         // Create request
 142         Log_Log("ARP4", "Asking for address %i.%i.%i.%i",
 143                 Address.B[0], Address.B[1], Address.B[2], Address.B[3]
 144                 );
 145         req.HWType = htons(0x0001);     // Ethernet
 146         req.Type   = htons(0x0800);
 147         req.HWSize = 6;
 148         req.SWSize = 4;
 149         req.Request = htons(1);
 150         memcpy(&req.SourceMac, Interface->Adapter->HWAddr, 6);  // TODO: Remove hard size
 151         req.SourceIP = *(tIPv4*)Interface->Address;
 152         req.DestMac = cMAC_BROADCAST;
 153         req.DestIP = Address;
 154
 155         // Assumes only a header and footer at link layer
 156         tIPStackBuffer  *buffer = IPStack_Buffer_CreateBuffer(3);
 157         IPStack_Buffer_AppendSubBuffer(buffer, sizeof(struct sArpRequest4), 0, &req, NULL, NULL);
 158
 159         // Send Request
 160         Link_SendPacket(Interface->Adapter, 0x0806, req.DestMac, buffer);
 161
 162         // Clean up
 163         IPStack_Buffer_DestroyBuffer(buffer);
 164
 165         // Wait for a reply
 166         Time_ScheduleTimer(NULL, Interface->TimeoutDelay);
 167         for(;;)
 168         {
 169                 if( Semaphore_Wait(&gARP_Cache4Semaphore, 1) != 1 )
 170                 {
 171                         giARP_WaitingThreads --;
 172                         Log_Log("ARP4", "Timeout");
 173                         break;
 174                 }
 175                 Log_Debug("ARP4", "Cache change");
 176
 177                 Mutex_Acquire( &glARP_Cache4 );
 178                 for( i = 0; i < giARP_Cache4Space; i++ )
 179                 {
 180                         if(gaARP_Cache4[i].IP.L != Address.L)   continue;
 181
 182                         giARP_WaitingThreads --;
 183                         Mutex_Release( &glARP_Cache4 );
 184                         Log_Debug("ARP4", "Return %02x:%02x:%02x:%02x:%02x:%02x",
 185                                 gaARP_Cache4[i].MAC.B[0], gaARP_Cache4[i].MAC.B[1],
 186                                 gaARP_Cache4[i].MAC.B[2], gaARP_Cache4[i].MAC.B[3],
 187                                 gaARP_Cache4[i].MAC.B[4], gaARP_Cache4[i].MAC.B[5]);
 188                         return gaARP_Cache4[i].MAC;
 189                 }
 190                 Mutex_Release( &glARP_Cache4 );
 191         }
 192         {
 193                 tMacAddr        ret = {{0,0,0,0,0,0}};
 194                 return ret;
 195         }
 196 }
 197
 198 /**
 199  * \brief Updates the ARP Cache entry for an IPv4 Address
 200  */
 201 void ARP_UpdateCache4(tIPv4 SWAddr, tMacAddr HWAddr)
 202 {
 203          int    i;
 204          int    free = -1;
 205          int    oldest = 0;
 206
 207         // Find an entry for the IP address in the cache
 208         Mutex_Acquire(&glARP_Cache4);
 209         for( i = giARP_Cache4Space; i--; )
 210         {
 211                 if(gaARP_Cache4[oldest].LastUpdate > gaARP_Cache4[i].LastUpdate) {
 212                         oldest = i;
 213                 }
 214                 if( gaARP_Cache4[i].IP.L == SWAddr.L )  break;
 215                 if( gaARP_Cache4[i].LastUpdate == 0 && free == -1 )     free = i;
 216         }
 217         // If there was no match, we need to make one
 218         if(i == -1) {
 219                 if(free != -1)
 220                         i = free;
 221                 else
 222                         i = oldest;
 223         }
 224
 225         Log_Log("ARP4", "Caching %i.%i.%i.%i (%02x:%02x:%02x:%02x:%02x:%02x) in %i",
 226                 SWAddr.B[0], SWAddr.B[1], SWAddr.B[2], SWAddr.B[3],
 227                 HWAddr.B[0], HWAddr.B[1], HWAddr.B[2], HWAddr.B[3], HWAddr.B[4], HWAddr.B[5],
 228                 i
 229                 );
 230
 231         gaARP_Cache4[i].IP = SWAddr;
 232         gaARP_Cache4[i].MAC = HWAddr;
 233         gaARP_Cache4[i].LastUpdate = now();
 234         Semaphore_Signal(&gARP_Cache4Semaphore, giARP_WaitingThreads);
 235         Mutex_Release(&glARP_Cache4);
 236 }
 237
 238 #if ARPv6
 239 /**
 240  * \brief Updates the ARP Cache entry for an IPv6 Address
 241  */
 242 void ARP_UpdateCache6(tIPv6 SWAddr, tMacAddr HWAddr)
 243 {
 244          int    i;
 245          int    free = -1;
 246          int    oldest = 0;
 247
 248         // Find an entry for the MAC address in the cache
 249         Mutex_Acquire(&glARP_Cache6);
 250         for( i = giARP_Cache6Space; i--; )
 251         {
 252                 if(gaARP_Cache6[oldest].LastUpdate > gaARP_Cache6[i].LastUpdate) {
 253                         oldest = i;
 254                 }
 255                 if( MAC_EQU(gaARP_Cache6[i].MAC, HWAddr) )      break;
 256                 if( gaARP_Cache6[i].LastUpdate == 0 && free == -1 )     free = i;
 257         }
 258         // If there was no match, we need to make one
 259         if(i == -1) {
 260                 if(free != -1)
 261                         i = free;
 262                 else
 263                         i = oldest;
 264                 gaARP_Cache6[i].MAC = HWAddr;
 265         }
 266
 267         gaARP_Cache6[i].IP = SWAddr;
 268         gaARP_Cache6[i].LastUpdate = now();
 269         giARP_LastUpdateID ++;
 270         Mutex_Release(&glARP_Cache6);
 271 }
 272 #endif
 273
 274 /**
 275  * \fn void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
 276  * \brief Called when an ARP packet is recieved
 277  */
 278 void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
 279 {
 280         tArpRequest4    *req4 = Buffer;
 281         #if ARPv6
 282         tArpRequest6    *req6 = Buffer;
 283         #endif
 284         tInterface      *iface;
 285
 286         // Sanity Check Packet
 287         if( Length < (int)sizeof(tArpRequest4) ) {
 288                 Log_Log("ARP", "Recieved undersized packet");
 289                 return ;
 290         }
 291         if( ntohs(req4->Type) != 0x0800 ) {
 292                 Log_Log("ARP", "Recieved a packet with a bad type (0x%x)", ntohs(req4->Type));
 293                 return ;
 294         }
 295         if( req4->HWSize != 6 ) {
 296                 Log_Log("ARP", "Recieved a packet with HWSize != 6 (%i)", req4->HWSize);
 297                 return;
 298         }
 299         #if ARP_DETECT_SPOOFS
 300         if( !MAC_EQU(req4->SourceMac, From) ) {
 301                 Log_Log("ARP", "ARP spoofing detected "
 302                         "(%02x%02x:%02x%02x:%02x%02x != %02x%02x:%02x%02x:%02x%02x)",
 303                         req4->SourceMac.B[0], req4->SourceMac.B[1], req4->SourceMac.B[2],
 304                         req4->SourceMac.B[3], req4->SourceMac.B[4], req4->SourceMac.B[5],
 305                         From.B[0], From.B[1], From.B[2],
 306                         From.B[3], From.B[4], From.B[5]
 307                         );
 308                 return;
 309         }
 310         #endif
 311
 312         switch( ntohs(req4->Request) )
 313         {
 314         case 1: // You want my IP?
 315                 // Check what type of IP it is
 316                 switch( req4->SWSize )
 317                 {
 318                 case 4:
 319                         Log_Debug("ARP", "ARP Request IPv4 Address %i.%i.%i.%i from %i.%i.%i.%i",
 320                                 req4->DestIP.B[0], req4->DestIP.B[1], req4->DestIP.B[2],
 321                                 req4->DestIP.B[3],
 322                                 req4->SourceIP.B[0], req4->SourceIP.B[1],
 323                                 req4->SourceIP.B[2], req4->SourceIP.B[3]);
 324                         Log_Debug("ARP", " from MAC %02x:%02x:%02x:%02x:%02x:%02x",
 325                                 req4->SourceMac.B[0], req4->SourceMac.B[1],
 326                                 req4->SourceMac.B[2], req4->SourceMac.B[3],
 327                                 req4->SourceMac.B[4], req4->SourceMac.B[5]);
 328                         iface = IPv4_GetInterface(Adapter, req4->DestIP, 0);
 329                         if( iface )
 330                         {
 331                                 ARP_UpdateCache4(req4->SourceIP, req4->SourceMac);
 332
 333                                 req4->DestIP = req4->SourceIP;
 334                                 req4->DestMac = req4->SourceMac;
 335                                 req4->SourceIP = *(tIPv4*)iface->Address;;
 336                                 memcpy(&req4->SourceMac, Adapter->HWAddr, 6);   // TODO: Remove hard size
 337                                 req4->Request = htons(2);
 338                                 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
 339                                         req4->SourceMac.B[0], req4->SourceMac.B[1],
 340                                         req4->SourceMac.B[2], req4->SourceMac.B[3],
 341                                         req4->SourceMac.B[4], req4->SourceMac.B[5]);
 342
 343                                 // Assumes only a header and footer at link layer
 344                                 tIPStackBuffer  *buffer = IPStack_Buffer_CreateBuffer(3);
 345                                 IPStack_Buffer_AppendSubBuffer(buffer, sizeof(struct sArpRequest4), 0, req4, NULL, NULL);
 346                                 Link_SendPacket(Adapter, 0x0806, req4->DestMac, buffer);
 347                                 IPStack_Buffer_DestroyBuffer(buffer);
 348                         }
 349                         break;
 350                 #if ARPv6
 351                 case 6:
 352                         if( Length < (int)sizeof(tArpRequest6) ) {
 353                                 Log_Log("ARP", "Recieved undersized packet (IPv6)");
 354                                 return ;
 355                         }
 356                         Log_Debug("ARP", "ARP Request IPv6 Address %08x:%08x:%08x:%08x",
 357                                 ntohl(req6->DestIP.L[0]), ntohl(req6->DestIP.L[1]),
 358                                 ntohl(req6->DestIP.L[2]), ntohl(req6->DestIP.L[3])
 359                                 );
 360                         iface = IPv6_GetInterface(Adapter, req6->DestIP, 0);
 361                         if( iface )
 362                         {
 363                                 req6->DestIP = req6->SourceIP;
 364                                 req6->DestMac = req6->SourceMac;
 365                                 req6->SourceIP = *(tIPv6*)iface->Address;
 366                                 req6->SourceMac = Adapter->MacAddr;
 367                                 req6->Request = htons(2);
 368                                 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
 369                                         req4->SourceMac.B[0], req4->SourceMac.B[1],
 370                                         req4->SourceMac.B[2], req4->SourceMac.B[3],
 371                                         req4->SourceMac.B[4], req4->SourceMac.B[5]);
 372                                 Link_SendPacket(Adapter, 0x0806, req6->DestMac, sizeof(tArpRequest6), req6);
 373                         }
 374                         break;
 375                 #endif
 376                 default:
 377                         Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
 378                         return ;
 379                 }
 380
 381                 break;
 382
 383         case 2: // Ooh! A response!
 384                 // Check what type of IP it is
 385                 switch( req4->SWSize )
 386                 {
 387                 case 4:
 388                         ARP_UpdateCache4( req4->SourceIP, From );
 389                         break;
 390                 #if ARPv6
 391                 case 6:
 392                         if( Length < (int)sizeof(tArpRequest6) ) {
 393                                 Log_Debug("ARP", "Recieved undersized packet (IPv6)");
 394                                 return ;
 395                         }
 396                         ARP_UpdateCache6( req6->SourceIP, From );
 397                         break;
 398                 #endif
 399                 default:
 400                         Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
 401                         return ;
 402                 }
 403
 404                 break;
 405
 406         default:
 407                 Log_Warning("ARP", "Unknown Request ID %i", ntohs(req4->Request));
 408                 break;
 409         }
 410 }