KernelLand/Modules/IPStack/link.c

   1 /*
   2  * Acess2 Networking Stack
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * link.c
   6  * - Ethernet/802.3 Handling code
   7  * TODO: Rename file
   8  */
   9 #include "ipstack.h"
  10 #include "link.h"
  11 #include "include/buffer.h"
  12 #include "include/adapters_int.h"
  13
  14 // === CONSTANTS ===
  15 #define LINK_LOGPACKETS 0
  16 #define VALIDATE_CHECKSUM       0
  17 #define MAX_PACKET_SIZE 2048
  18
  19 // === TYPES ===
  20 typedef struct {
  21         Uint16  Type;
  22         tPacketCallback Callback;
  23 } tLink_PktType;
  24
  25
  26 // === PROTOTYPES ===
  27 void    Link_RegisterType(Uint16 Type, tPacketCallback Callback);
  28 void    Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, tIPStackBuffer *Buffer);
  29  int    Link_HandlePacket(tAdapter *Adapter, tIPStackBuffer *Buffer);
  30 // --- CRC ---
  31 void    Link_InitCRC(void);
  32 Uint32  Link_CalculateCRC(tIPStackBuffer *Buffer);
  33 Uint32  Link_CalculatePartialCRC(Uint32 CRC, const void *Data, int Length);
  34
  35 // === GLOBALS ===
  36  int    giRegisteredTypes = 0;
  37  int    giRegisteredTypeSpace = 0;
  38 tLink_PktType   *gaRegisteredTypes;
  39  int    gbLink_CRCTableGenerated = 0;
  40 Uint32  gaiLink_CRCTable[256];
  41
  42 // === CODE ===
  43 /**
  44  * \fn void Link_RegisterType(Uint16 Type, tPacketCallback Callback)
  45  * \brief Registers a callback for a specific packet type
  46  *
  47  * \todo Make thread safe (place a mutex on the list)
  48  */
  49 void Link_RegisterType(Uint16 Type, tPacketCallback Callback)
  50 {
  51         tLink_PktType *typeslot = NULL;
  52
  53         for( int i = 0; i < giRegisteredTypes; i ++)
  54         {
  55                 if(gaRegisteredTypes[i].Type == Type) {
  56                         Log_Warning("Net Link", "Attempt to register 0x%x twice", Type);
  57                         return ;
  58                 }
  59                 // Ooh! Free slot!
  60                 if(gaRegisteredTypes[i].Callback == NULL)
  61                 {
  62                         typeslot = &gaRegisteredTypes[i];
  63                         break;
  64                 }
  65         }
  66
  67         if(typeslot == NULL)
  68         {
  69                 if( giRegisteredTypes == giRegisteredTypeSpace )
  70                 {
  71                         giRegisteredTypeSpace += 5;
  72                         void *tmp = realloc(gaRegisteredTypes, giRegisteredTypeSpace*sizeof(tLink_PktType));
  73                         if(!tmp) {
  74                                 Log_Warning("Net Link",
  75                                         "Out of heap space! (Attempted to allocate %i)",
  76                                         giRegisteredTypeSpace*sizeof(tLink_PktType)
  77                                         );
  78                                 return ;
  79                         }
  80                         gaRegisteredTypes = tmp;
  81                 }
  82                 typeslot = &gaRegisteredTypes[giRegisteredTypes++];
  83         }
  84
  85         typeslot->Callback = Callback;
  86         typeslot->Type = Type;
  87 }
  88
  89 /**
  90  * \brief Formats and sends a packet on the specified interface
  91  */
  92 void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, tIPStackBuffer *Buffer)
  93 {
  94          int    length = IPStack_Buffer_GetLength(Buffer);
  95          int    ofs = (4 - (length & 3)) & 3;
  96         Uint8   buf[sizeof(tEthernetHeader) + ofs + 4];
  97         //Uint32        *checksum = (void*)(buf + sizeof(tEthernetHeader) + ofs);
  98         tEthernetHeader *hdr = (void*)buf;
  99
 100         hdr->Dest = To;
 101         memcpy(&hdr->Src, Adapter->HWAddr, 6);  // TODO: Remove hard coded 6
 102         hdr->Type = htons(Type);
 103         memset(hdr+1, 0, ofs+4);        // zero padding and checksum
 104
 105         Log_Log("Net Link", "Sending %i bytes (Type 0x%x)"
 106                 " to %02x:%02x:%02x:%02x:%02x:%02x"
 107                 " from %02x:%02x:%02x:%02x:%02x:%02x",
 108                 length, Type,
 109                 To.B[0], To.B[1], To.B[2], To.B[3], To.B[4], To.B[5],
 110                 hdr->Src.B[0], hdr->Src.B[1], hdr->Src.B[2],
 111                 hdr->Src.B[3], hdr->Src.B[4], hdr->Src.B[5]
 112                 );
 113
 114         #if 0
 115         if( (Adapter->Type->Flags & ADAPTERFLAG_OFFLOAD_MAC) )
 116         #endif
 117                 IPStack_Buffer_AppendSubBuffer(Buffer, sizeof(tEthernetHeader), ofs, hdr, NULL, NULL);
 118         #if 0
 119         else
 120         {
 121                 IPStack_Buffer_AppendSubBuffer(Buffer, sizeof(tEthernetHeader), ofs + 4, hdr, NULL, NULL);
 122                 *checksum = htonl( Link_CalculateCRC(Buffer) );
 123                 Log_Debug("Net Link", "Non-Offloaded: 0x%x, 0x%x", *checksum, ntohl(*checksum));
 124         }
 125         #endif
 126
 127         Adapter_SendPacket(Adapter, Buffer);
 128 }
 129
 130 int Link_HandlePacket(tAdapter *Adapter, tIPStackBuffer *Buffer)
 131 {
 132         size_t  len = 0;
 133         void    *data = IPStack_Buffer_CompactBuffer(Buffer, &len);
 134
 135         tEthernetHeader *hdr = (void*)data;
 136
 137         if(len < sizeof(tEthernetHeader)) {
 138                 Log_Log("Net Link", "Recieved an undersized packet (%i < %i)",
 139                         len, sizeof(tEthernetHeader));
 140                 free(data);
 141                 return 1;
 142         }
 143
 144         #if LINK_LOGPACKETS
 145         Log_Log("Net Link",
 146                 "eth%i Packet from %02x:%02x:%02x:%02x:%02x:%02x"
 147                 " to %02x:%02x:%02x:%02x:%02x:%02x (Type=%04x)",
 148                 Adapter->Index,
 149                 hdr->Src.B[0], hdr->Src.B[1], hdr->Src.B[2],
 150                 hdr->Src.B[3], hdr->Src.B[4], hdr->Src.B[5],
 151                 hdr->Dest.B[0], hdr->Dest.B[1], hdr->Dest.B[2],
 152                 hdr->Dest.B[3], hdr->Dest.B[4], hdr->Dest.B[5],
 153                 ntohs(hdr->Type)
 154                 );
 155         #endif
 156
 157         #if VALIDATE_CHECKSUM
 158         Uint32 checksum = *(Uint32*)(data + len + 4);
 159         Log_Log("NET Link", "Checksum 0x%08x", checksum);
 160         Uint32  calculated = Link_CalculateCRC(Buffer);
 161         // TODO: Check checksum
 162         #endif
 163
 164         Uint16  type = ntohs(hdr->Type);
 165         // Check if there is a registered callback for this packet type
 166         for( int i = giRegisteredTypes; i--; )
 167         {
 168                 if(gaRegisteredTypes[i].Type == type)
 169                 {
 170                         // Call the callback
 171                         gaRegisteredTypes[i].Callback(
 172                                 Adapter,
 173                                 hdr->Src,
 174                                 len - sizeof(tEthernetHeader),
 175                                 hdr->Data
 176                                 );
 177                         free(data);
 178                         return 0;
 179                 }
 180         }
 181         // No? Ignore it
 182         Log_Log("Net Link", "eth%i Unregistered type 0x%04x", Adapter->Index, type);
 183
 184         free(data);
 185         return 1;
 186 }
 187
 188 // From http://www.cl.cam.ac.uk/research/srg/bluebook/21/crc/node6.html
 189 #define QUOTIENT        0x04c11db7
 190 void Link_InitCRC(void)
 191 {
 192         for( int i = 0; i < 256; i++ )
 193         {
 194                 Uint32 crc = i << 24;
 195                 for( int j = 0; j < 8; j++ )
 196                 {
 197                         if( crc >> 31 )
 198                                 crc = (crc << 1) ^ QUOTIENT;
 199                         else
 200                                 crc = crc << 1;
 201                 }
 202                 gaiLink_CRCTable[i] = crc;
 203         }
 204
 205         gbLink_CRCTableGenerated = 1;
 206 }
 207
 208 Uint32 Link_CalculateCRC(tIPStackBuffer *Buffer)
 209 {
 210         Uint32  ret = 0xFFFFFFFF;
 211         const void      *data;
 212         size_t  length;
 213
 214          int    id = -1;
 215         while( (id = IPStack_Buffer_GetBuffer(Buffer, id, &length, &data)) != -1 )
 216         {
 217                 ret = Link_CalculatePartialCRC(ret, data, length);
 218         }
 219
 220         return ~ret;
 221 }
 222
 223 Uint32 Link_CalculatePartialCRC(Uint32 CRC, const void *Data, int Length)
 224 {
 225         // x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1
 226         const Uint32    *data = Data;
 227
 228         for( int i = 0; i < Length/4; i++ )
 229         {
 230                 CRC = (CRC << 8 | *data++) ^ gaiLink_CRCTable[CRC >> 24];
 231         }
 232
 233         return CRC;
 234 }