Modules/IPStack/arp.c

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