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         if( memcmp(&gaARP_Cache4[i].MAC, &HWAddr, sizeof(HWAddr)) != 0 )
 226         {
 227                 Log_Log("ARP4", "Caching %i.%i.%i.%i (%02x:%02x:%02x:%02x:%02x:%02x) in %i",
 228                         SWAddr.B[0], SWAddr.B[1], SWAddr.B[2], SWAddr.B[3],
 229                         HWAddr.B[0], HWAddr.B[1], HWAddr.B[2], HWAddr.B[3], HWAddr.B[4], HWAddr.B[5],
 230                         i
 231                         );
 232
 233                 gaARP_Cache4[i].IP = SWAddr;
 234                 gaARP_Cache4[i].MAC = HWAddr;
 235                 gaARP_Cache4[i].LastUpdate = now();
 236                 Semaphore_Signal(&gARP_Cache4Semaphore, giARP_WaitingThreads);
 237         }
 238         Mutex_Release(&glARP_Cache4);
 239 }
 240
 241 #if ARPv6
 242 /**
 243  * \brief Updates the ARP Cache entry for an IPv6 Address
 244  */
 245 void ARP_UpdateCache6(tIPv6 SWAddr, tMacAddr HWAddr)
 246 {
 247          int    i;
 248          int    free = -1;
 249          int    oldest = 0;
 250
 251         // Find an entry for the MAC address in the cache
 252         Mutex_Acquire(&glARP_Cache6);
 253         for( i = giARP_Cache6Space; i--; )
 254         {
 255                 if(gaARP_Cache6[oldest].LastUpdate > gaARP_Cache6[i].LastUpdate) {
 256                         oldest = i;
 257                 }
 258                 if( MAC_EQU(gaARP_Cache6[i].MAC, HWAddr) )      break;
 259                 if( gaARP_Cache6[i].LastUpdate == 0 && free == -1 )     free = i;
 260         }
 261         // If there was no match, we need to make one
 262         if(i == -1) {
 263                 if(free != -1)
 264                         i = free;
 265                 else
 266                         i = oldest;
 267                 gaARP_Cache6[i].MAC = HWAddr;
 268         }
 269
 270         gaARP_Cache6[i].IP = SWAddr;
 271         gaARP_Cache6[i].LastUpdate = now();
 272         giARP_LastUpdateID ++;
 273         Mutex_Release(&glARP_Cache6);
 274 }
 275 #endif
 276
 277 /**
 278  * \fn void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
 279  * \brief Called when an ARP packet is recieved
 280  */
 281 void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
 282 {
 283         tArpRequest4    *req4 = Buffer;
 284         #if ARPv6
 285         tArpRequest6    *req6 = Buffer;
 286         #endif
 287         tInterface      *iface;
 288
 289         // Sanity Check Packet
 290         if( Length < (int)sizeof(tArpRequest4) ) {
 291                 Log_Log("ARP", "Recieved undersized packet");
 292                 return ;
 293         }
 294         if( ntohs(req4->Type) != 0x0800 ) {
 295                 Log_Log("ARP", "Recieved a packet with a bad type (0x%x)", ntohs(req4->Type));
 296                 return ;
 297         }
 298         if( req4->HWSize != 6 ) {
 299                 Log_Log("ARP", "Recieved a packet with HWSize != 6 (%i)", req4->HWSize);
 300                 return;
 301         }
 302         #if ARP_DETECT_SPOOFS
 303         if( !MAC_EQU(req4->SourceMac, From) ) {
 304                 Log_Log("ARP", "ARP spoofing detected "
 305                         "(%02x%02x:%02x%02x:%02x%02x != %02x%02x:%02x%02x:%02x%02x)",
 306                         req4->SourceMac.B[0], req4->SourceMac.B[1], req4->SourceMac.B[2],
 307                         req4->SourceMac.B[3], req4->SourceMac.B[4], req4->SourceMac.B[5],
 308                         From.B[0], From.B[1], From.B[2],
 309                         From.B[3], From.B[4], From.B[5]
 310                         );
 311                 return;
 312         }
 313         #endif
 314
 315         switch( ntohs(req4->Request) )
 316         {
 317         case 1: // You want my IP?
 318                 // Check what type of IP it is
 319                 switch( req4->SWSize )
 320                 {
 321                 case 4:
 322                         Log_Debug("ARP", "ARP Request IPv4 Address %i.%i.%i.%i from %i.%i.%i.%i",
 323                                 req4->DestIP.B[0], req4->DestIP.B[1], req4->DestIP.B[2],
 324                                 req4->DestIP.B[3],
 325                                 req4->SourceIP.B[0], req4->SourceIP.B[1],
 326                                 req4->SourceIP.B[2], req4->SourceIP.B[3]);
 327                         Log_Debug("ARP", " from MAC %02x:%02x:%02x:%02x:%02x:%02x",
 328                                 req4->SourceMac.B[0], req4->SourceMac.B[1],
 329                                 req4->SourceMac.B[2], req4->SourceMac.B[3],
 330                                 req4->SourceMac.B[4], req4->SourceMac.B[5]);
 331                         iface = IPv4_GetInterface(Adapter, req4->DestIP, 0);
 332                         if( iface )
 333                         {
 334                                 ARP_UpdateCache4(req4->SourceIP, req4->SourceMac);
 335
 336                                 req4->DestIP = req4->SourceIP;
 337                                 req4->DestMac = req4->SourceMac;
 338                                 req4->SourceIP = *(tIPv4*)iface->Address;;
 339                                 memcpy(&req4->SourceMac, Adapter->HWAddr, 6);   // TODO: Remove hard size
 340                                 req4->Request = htons(2);
 341                                 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
 342                                         req4->SourceMac.B[0], req4->SourceMac.B[1],
 343                                         req4->SourceMac.B[2], req4->SourceMac.B[3],
 344                                         req4->SourceMac.B[4], req4->SourceMac.B[5]);
 345
 346                                 // Assumes only a header and footer at link layer
 347                                 tIPStackBuffer  *buffer = IPStack_Buffer_CreateBuffer(3);
 348                                 IPStack_Buffer_AppendSubBuffer(buffer, sizeof(struct sArpRequest4), 0, req4, NULL, NULL);
 349                                 Link_SendPacket(Adapter, 0x0806, req4->DestMac, buffer);
 350                                 IPStack_Buffer_DestroyBuffer(buffer);
 351                         }
 352                         break;
 353                 #if ARPv6
 354                 case 6:
 355                         if( Length < (int)sizeof(tArpRequest6) ) {
 356                                 Log_Log("ARP", "Recieved undersized packet (IPv6)");
 357                                 return ;
 358                         }
 359                         Log_Debug("ARP", "ARP Request IPv6 Address %08x:%08x:%08x:%08x",
 360                                 ntohl(req6->DestIP.L[0]), ntohl(req6->DestIP.L[1]),
 361                                 ntohl(req6->DestIP.L[2]), ntohl(req6->DestIP.L[3])
 362                                 );
 363                         iface = IPv6_GetInterface(Adapter, req6->DestIP, 0);
 364                         if( iface )
 365                         {
 366                                 req6->DestIP = req6->SourceIP;
 367                                 req6->DestMac = req6->SourceMac;
 368                                 req6->SourceIP = *(tIPv6*)iface->Address;
 369                                 req6->SourceMac = Adapter->MacAddr;
 370                                 req6->Request = htons(2);
 371                                 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
 372                                         req4->SourceMac.B[0], req4->SourceMac.B[1],
 373                                         req4->SourceMac.B[2], req4->SourceMac.B[3],
 374                                         req4->SourceMac.B[4], req4->SourceMac.B[5]);
 375                                 Link_SendPacket(Adapter, 0x0806, req6->DestMac, sizeof(tArpRequest6), req6);
 376                         }
 377                         break;
 378                 #endif
 379                 default:
 380                         Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
 381                         return ;
 382                 }
 383
 384                 break;
 385
 386         case 2: // Ooh! A response!
 387                 // Check what type of IP it is
 388                 switch( req4->SWSize )
 389                 {
 390                 case 4:
 391                         ARP_UpdateCache4( req4->SourceIP, From );
 392                         break;
 393                 #if ARPv6
 394                 case 6:
 395                         if( Length < (int)sizeof(tArpRequest6) ) {
 396                                 Log_Debug("ARP", "Recieved undersized packet (IPv6)");
 397                                 return ;
 398                         }
 399                         ARP_UpdateCache6( req6->SourceIP, From );
 400                         break;
 401                 #endif
 402                 default:
 403                         Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
 404                         return ;
 405                 }
 406
 407                 break;
 408
 409         default:
 410                 Log_Warning("ARP", "Unknown Request ID %i", ntohs(req4->Request));
 411                 break;
 412         }
 413 }