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