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         Mutex_Acquire( &glARP_Cache4 );
  79         for( i = 0; i < giARP_Cache4Space; i++ )
  80         {
  81                 if(gaARP_Cache4[i].IP.L != Address.L)   continue;
  82
  83                 // Check if the entry needs to be refreshed
  84                 if( now() - gaARP_Cache4[i].LastUpdate > ARP_MAX_AGE )  break;
  85
  86                 Mutex_Release( &glARP_Cache4 );
  87                 LOG("Return %x:%x:%x:%x:%x:%x",
  88                         gaARP_Cache4[i].MAC.B[0], gaARP_Cache4[i].MAC.B[1],
  89                         gaARP_Cache4[i].MAC.B[2], gaARP_Cache4[i].MAC.B[3],
  90                         gaARP_Cache4[i].MAC.B[4], gaARP_Cache4[i].MAC.B[5]
  91                         );
  92                 LEAVE('-');
  93                 return gaARP_Cache4[i].MAC;
  94         }
  95         Mutex_Release( &glARP_Cache4 );
  96
  97         lastID = giARP_LastUpdateID;
  98
  99         // Create request
 100         Log_Log("ARP4", "Asking for address %i.%i.%i.%i",
 101                 Address.B[0], Address.B[1], Address.B[2], Address.B[3]
 102                 );
 103         req.HWType = htons(0x0001);     // Ethernet
 104         req.Type   = htons(0x0800);
 105         req.HWSize = 6;
 106         req.SWSize = 4;
 107         req.Request = htons(1);
 108         req.SourceMac = Interface->Adapter->MacAddr;
 109         req.SourceIP = Interface->IP4.Address;
 110         req.DestMac = cMAC_BROADCAST;
 111         req.DestIP = Address;
 112
 113         // Send Request
 114         Link_SendPacket(Interface->Adapter, 0x0806, req.DestMac, sizeof(struct sArpRequest4), &req);
 115
 116         // Wait for a reply
 117         for(;;)
 118         {
 119                 while(lastID == giARP_LastUpdateID)     Threads_Yield();
 120                 lastID = giARP_LastUpdateID;
 121
 122                 Mutex_Acquire( &glARP_Cache4 );
 123                 for( i = 0; i < giARP_Cache4Space; i++ )
 124                 {
 125                         if(gaARP_Cache4[i].IP.L != Address.L)   continue;
 126
 127                         Mutex_Release( &glARP_Cache4 );
 128                         return gaARP_Cache4[i].MAC;
 129                 }
 130                 Mutex_Release( &glARP_Cache4 );
 131         }
 132 }
 133
 134 /**
 135  * \brief Updates the ARP Cache entry for an IPv4 Address
 136  */
 137 void ARP_UpdateCache4(tIPv4 SWAddr, tMacAddr HWAddr)
 138 {
 139          int    i;
 140          int    free = -1;
 141          int    oldest = 0;
 142
 143         // Find an entry for the IP address in the cache
 144         Mutex_Acquire(&glARP_Cache4);
 145         for( i = giARP_Cache4Space; i--; )
 146         {
 147                 if(gaARP_Cache4[oldest].LastUpdate > gaARP_Cache4[i].LastUpdate) {
 148                         oldest = i;
 149                 }
 150                 if( gaARP_Cache4[i].IP.L == SWAddr.L )  break;
 151                 if( gaARP_Cache4[i].LastUpdate == 0 && free == -1 )     free = i;
 152         }
 153         // If there was no match, we need to make one
 154         if(i == -1) {
 155                 if(free != -1)
 156                         i = free;
 157                 else
 158                         i = oldest;
 159                 gaARP_Cache4[i].IP = SWAddr;
 160         }
 161
 162         Log_Log("ARP4", "Caching %i.%i.%i.%i (%02x:%02x:%02x:%02x:%02x:%02x) in %i",
 163                 SWAddr.B[0], SWAddr.B[1], SWAddr.B[2], SWAddr.B[3],
 164                 HWAddr.B[0], HWAddr.B[1], HWAddr.B[2], HWAddr.B[3], HWAddr.B[4], HWAddr.B[5],
 165                 i
 166                 );
 167
 168         gaARP_Cache4[i].MAC = HWAddr;
 169         gaARP_Cache4[i].LastUpdate = now();
 170         giARP_LastUpdateID ++;
 171         Mutex_Release(&glARP_Cache4);
 172 }
 173
 174 #if ARPv6
 175 /**
 176  * \brief Updates the ARP Cache entry for an IPv6 Address
 177  */
 178 void ARP_UpdateCache6(tIPv6 SWAddr, tMacAddr HWAddr)
 179 {
 180          int    i;
 181          int    free = -1;
 182          int    oldest = 0;
 183
 184         // Find an entry for the MAC address in the cache
 185         Mutex_Acquire(&glARP_Cache6);
 186         for( i = giARP_Cache6Space; i--; )
 187         {
 188                 if(gaARP_Cache6[oldest].LastUpdate > gaARP_Cache6[i].LastUpdate) {
 189                         oldest = i;
 190                 }
 191                 if( MAC_EQU(gaARP_Cache6[i].MAC, HWAddr) )      break;
 192                 if( gaARP_Cache6[i].LastUpdate == 0 && free == -1 )     free = i;
 193         }
 194         // If there was no match, we need to make one
 195         if(i == -1) {
 196                 if(free != -1)
 197                         i = free;
 198                 else
 199                         i = oldest;
 200                 gaARP_Cache6[i].MAC = HWAddr;
 201         }
 202
 203         gaARP_Cache6[i].IP = SWAddr;
 204         gaARP_Cache6[i].LastUpdate = now();
 205         giARP_LastUpdateID ++;
 206         Mutex_Release(&glARP_Cache6);
 207 }
 208 #endif
 209
 210 /**
 211  * \fn void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
 212  * \brief Called when an ARP packet is recieved
 213  */
 214 void ARP_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buffer)
 215 {
 216         tArpRequest4    *req4 = Buffer;
 217         #if ARPv6
 218         tArpRequest6    *req6 = Buffer;
 219         #endif
 220         tInterface      *iface;
 221
 222         // Sanity Check Packet
 223         if( Length < (int)sizeof(tArpRequest4) ) {
 224                 Log_Log("ARP", "Recieved undersized packet");
 225                 return ;
 226         }
 227         if( ntohs(req4->Type) != 0x0800 ) {
 228                 Log_Log("ARP", "Recieved a packet with a bad type (0x%x)", ntohs(req4->Type));
 229                 return ;
 230         }
 231         if( req4->HWSize != 6 ) {
 232                 Log_Log("ARP", "Recieved a packet with HWSize != 6 (%i)", req4->HWSize);
 233                 return;
 234         }
 235         #if ARP_DETECT_SPOOFS
 236         if( !MAC_EQU(req4->SourceMac, From) ) {
 237                 Log_Log("ARP", "ARP spoofing detected "
 238                         "(%02x%02x:%02x%02x:%02x%02x != %02x%02x:%02x%02x:%02x%02x)",
 239                         req4->SourceMac.B[0], req4->SourceMac.B[1], req4->SourceMac.B[2],
 240                         req4->SourceMac.B[3], req4->SourceMac.B[4], req4->SourceMac.B[5],
 241                         From.B[0], From.B[1], From.B[2],
 242                         From.B[3], From.B[4], From.B[5]
 243                         );
 244                 return;
 245         }
 246         #endif
 247
 248         Log_Debug("ARP", "Request ID %i", ntohs(req4->Request));
 249
 250         switch( ntohs(req4->Request) )
 251         {
 252         case 1: // You want my IP?
 253                 Log_Debug("ARP", "ARP Request Address class %i", req4->SWSize);
 254                 // Check what type of IP it is
 255                 switch( req4->SWSize )
 256                 {
 257                 case 4:
 258                         Log_Debug("ARP", "From MAC %02x:%02x:%02x:%02x:%02x:%02x",
 259                                 req4->SourceMac.B[0], req4->SourceMac.B[1],
 260                                 req4->SourceMac.B[2], req4->SourceMac.B[3],
 261                                 req4->SourceMac.B[4], req4->SourceMac.B[5]);
 262                         //Log_Debug("ARP", "to MAC %02x:%02x:%02x:%02x:%02x:%02x",
 263                         //      req4->DestMac.B[0], req4->DestMac.B[1],
 264                         //      req4->DestMac.B[2], req4->DestMac.B[3],
 265                         //      req4->DestMac.B[4], req4->DestMac.B[5]);
 266                         Log_Debug("ARP", "ARP Request IPv4 Address %i.%i.%i.%i from %i.%i.%i.%i",
 267                                 req4->DestIP.B[0], req4->DestIP.B[1], req4->DestIP.B[2],
 268                                 req4->DestIP.B[3],
 269                                 req4->SourceIP.B[0], req4->SourceIP.B[1],
 270                                 req4->SourceIP.B[2], req4->SourceIP.B[3]);
 271                         iface = IPv4_GetInterface(Adapter, req4->DestIP, 0);
 272                         if( iface )
 273                         {
 274                                 Log_Debug("ARP", "Caching sender's IP Address");
 275                                 ARP_UpdateCache4(req4->SourceIP, req4->SourceMac);
 276
 277                                 req4->DestIP = req4->SourceIP;
 278                                 req4->DestMac = req4->SourceMac;
 279                                 req4->SourceIP = iface->IP4.Address;
 280                                 req4->SourceMac = Adapter->MacAddr;
 281                                 req4->Request = htons(2);
 282                                 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
 283                                         req4->SourceMac.B[0], req4->SourceMac.B[1],
 284                                         req4->SourceMac.B[2], req4->SourceMac.B[3],
 285                                         req4->SourceMac.B[4], req4->SourceMac.B[5]);
 286                                 Link_SendPacket(Adapter, 0x0806, req4->DestMac, sizeof(tArpRequest4), req4);
 287                         }
 288                         break;
 289                 #if ARPv6
 290                 case 6:
 291                         if( Length < (int)sizeof(tArpRequest6) ) {
 292                                 Log_Log("ARP", "Recieved undersized packet (IPv6)");
 293                                 return ;
 294                         }
 295                         Log_Debug("ARP", "ARP Request IPv6 Address %08x:%08x:%08x:%08x",
 296                                 ntohl(req6->DestIP.L[0]), ntohl(req6->DestIP.L[1]),
 297                                 ntohl(req6->DestIP.L[2]), ntohl(req6->DestIP.L[3])
 298                                 );
 299                         iface = IPv6_GetInterface(Adapter, req6->DestIP, 0);
 300                         if( iface )
 301                         {
 302                                 req6->DestIP = req6->SourceIP;
 303                                 req6->DestMac = req6->SourceMac;
 304                                 req6->SourceIP = iface->IP6.Address;
 305                                 req6->SourceMac = Adapter->MacAddr;
 306                                 req6->Request = htons(2);
 307                                 Log_Debug("ARP", "Sending back us (%02x:%02x:%02x:%02x:%02x:%02x)",
 308                                         req4->SourceMac.B[0], req4->SourceMac.B[1],
 309                                         req4->SourceMac.B[2], req4->SourceMac.B[3],
 310                                         req4->SourceMac.B[4], req4->SourceMac.B[5]);
 311                                 Link_SendPacket(Adapter, 0x0806, req6->DestMac, sizeof(tArpRequest6), req6);
 312                         }
 313                         break;
 314                 #endif
 315                 default:
 316                         Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
 317                         return ;
 318                 }
 319
 320                 break;
 321
 322         case 2: // Ooh! A response!
 323                 // Check what type of IP it is
 324                 switch( req4->SWSize )
 325                 {
 326                 case 4:
 327                         ARP_UpdateCache4( req4->SourceIP, From );
 328                         break;
 329                 #if ARPv6
 330                 case 6:
 331                         if( Length < (int)sizeof(tArpRequest6) ) {
 332                                 Log_Debug("ARP", "Recieved undersized packet (IPv6)");
 333                                 return ;
 334                         }
 335                         ARP_UpdateCache6( req6->SourceIP, From );
 336                         break;
 337                 #endif
 338                 default:
 339                         Log_Debug("ARP", "Unknown Protocol Address size (%i)", req4->SWSize);
 340                         return ;
 341                 }
 342
 343                 break;
 344
 345         default:
 346                 Log_Warning("ARP", "Unknown Request ID %i", ntohs(req4->Request));
 347                 break;
 348         }
 349 }