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 MAX_PACKET_SIZE 2048
  16
  17 // === PROTOTYPES ===
  18 void    Link_RegisterType(Uint16 Type, tPacketCallback Callback);
  19 void    Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, tIPStackBuffer *Buffer);
  20  int    Link_HandlePacket(tAdapter *Adapter, tIPStackBuffer *Buffer);
  21 // --- CRC ---
  22 void    Link_InitCRC(void);
  23 Uint32  Link_CalculateCRC(tIPStackBuffer *Buffer);
  24 Uint32  Link_CalculatePartialCRC(Uint32 CRC, const void *Data, int Length);
  25
  26 // === GLOBALS ===
  27  int    giRegisteredTypes = 0;
  28  int    giRegisteredTypeSpace = 0;
  29 struct {
  30         Uint16  Type;
  31         tPacketCallback Callback;
  32 }       *gaRegisteredTypes;
  33  int    gbLink_CRCTableGenerated = 0;
  34 Uint32  gaiLink_CRCTable[256];
  35
  36 // === CODE ===
  37 /**
  38  * \fn void Link_RegisterType(Uint16 Type, tPacketCallback Callback)
  39  * \brief Registers a callback for a specific packet type
  40  *
  41  * \todo Make thread safe (place a mutex on the list)
  42  */
  43 void Link_RegisterType(Uint16 Type, tPacketCallback Callback)
  44 {
  45          int    i;
  46         void    *tmp;
  47
  48         for( i = giRegisteredTypes; i -- ; )
  49         {
  50                 if(gaRegisteredTypes[i].Type == Type) {
  51                         Log_Warning("Net Link", "Attempt to register 0x%x twice", Type);
  52                         return ;
  53                 }
  54                 // Ooh! Free slot!
  55                 if(gaRegisteredTypes[i].Callback == NULL)       break;
  56         }
  57
  58         if(i == -1)
  59         {
  60                 giRegisteredTypeSpace += 5;
  61                 tmp = realloc(gaRegisteredTypes, giRegisteredTypeSpace*sizeof(*gaRegisteredTypes));
  62                 if(!tmp) {
  63                         Log_Warning("Net Link",
  64                                 "Out of heap space! (Attempted to allocate %i)",
  65                                 giRegisteredTypeSpace*sizeof(*gaRegisteredTypes)
  66                                 );
  67                         return ;
  68                 }
  69                 gaRegisteredTypes = tmp;
  70                 i = giRegisteredTypes;
  71                 giRegisteredTypes ++;
  72         }
  73
  74         gaRegisteredTypes[i].Callback = Callback;
  75         gaRegisteredTypes[i].Type = Type;
  76 }
  77
  78 /**
  79  * \fn void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, int Length, void *Buffer)
  80  * \brief Formats and sends a packet on the specified interface
  81  */
  82 void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, tIPStackBuffer *Buffer)
  83 {
  84          int    length = IPStack_Buffer_GetLength(Buffer);
  85          int    ofs = 4 - (length & 3);
  86         Uint8   buf[sizeof(tEthernetHeader) + ofs + 4];
  87         tEthernetHeader *hdr = (void*)buf;
  88
  89         if( ofs == 4 )  ofs = 0;
  90
  91         Log_Log("Net Link", "Sending %i bytes to %02x:%02x:%02x:%02x:%02x:%02x (Type 0x%x)",
  92                 length, To.B[0], To.B[1], To.B[2], To.B[3], To.B[4], To.B[5], Type);
  93
  94         hdr->Dest = To;
  95         memcpy(&hdr->Src, Adapter->HWAddr, 6);  // TODO: Remove hard coded 6
  96         hdr->Type = htons(Type);
  97         *(Uint32*)(buf + sizeof(tEthernetHeader) + ofs) = 0;
  98
  99         IPStack_Buffer_AppendSubBuffer(Buffer, sizeof(tEthernetHeader), ofs + 4, hdr, NULL, NULL);
 100
 101         *(Uint32*)(buf + sizeof(tEthernetHeader) + ofs) = htonl( Link_CalculateCRC(Buffer) );
 102
 103         Log_Log("Net Link", " from %02x:%02x:%02x:%02x:%02x:%02x",
 104                 hdr->Src.B[0], hdr->Src.B[1], hdr->Src.B[2],
 105                 hdr->Src.B[3], hdr->Src.B[4], hdr->Src.B[5]
 106                 );
 107
 108         Adapter_SendPacket(Adapter, Buffer);
 109 }
 110
 111 int Link_HandlePacket(tAdapter *Adapter, tIPStackBuffer *Buffer)
 112 {
 113         size_t  len = 0;
 114         void    *data = IPStack_Buffer_CompactBuffer(Buffer, &len);
 115
 116         tEthernetHeader *hdr = (void*)data;
 117
 118         if(len < sizeof(tEthernetHeader)) {
 119                 Log_Log("Net Link", "Recieved an undersized packet (%i < %i)",
 120                         len, sizeof(tEthernetHeader));
 121                 free(data);
 122                 return 1;
 123         }
 124
 125         Log_Log("Net Link",
 126                 "Packet from %02x:%02x:%02x:%02x:%02x:%02x"
 127                 " to %02x:%02x:%02x:%02x:%02x:%02x (Type=%04x)",
 128                 hdr->Src.B[0], hdr->Src.B[1], hdr->Src.B[2],
 129                 hdr->Src.B[3], hdr->Src.B[4], hdr->Src.B[5],
 130                 hdr->Dest.B[0], hdr->Dest.B[1], hdr->Dest.B[2],
 131                 hdr->Dest.B[3], hdr->Dest.B[4], hdr->Dest.B[5],
 132                 ntohs(hdr->Type)
 133                 );
 134 //      Uint32 checksum = *(Uint32*)(data + len + 4);
 135         //Log_Log("NET", "Checksum 0x%08x", checksum);
 136         // TODO: Check checksum
 137
 138         // Check if there is a registered callback for this packet type
 139          int    i;
 140         for( i = giRegisteredTypes; i--; )
 141         {
 142                 if(gaRegisteredTypes[i].Type == ntohs(hdr->Type))       break;
 143         }
 144         // No? Ignore it
 145         if( i == -1 ) {
 146                 Log_Log("Net Link", "Unregistered type 0x%x", ntohs(hdr->Type));
 147
 148                 free(data);
 149                 return 1;
 150         }
 151
 152         // Call the callback
 153         gaRegisteredTypes[i].Callback(
 154                 Adapter,
 155                 hdr->Src,
 156                 len - sizeof(tEthernetHeader),
 157                 hdr->Data
 158                 );
 159
 160         free(data);
 161
 162         return 0;
 163 }
 164
 165 // From http://www.cl.cam.ac.uk/research/srg/bluebook/21/crc/node6.html
 166 #define QUOTIENT        0x04c11db7
 167 void Link_InitCRC(void)
 168 {
 169          int    i, j;
 170         Uint32  crc;
 171
 172         for (i = 0; i < 256; i++)
 173         {
 174                 crc = i << 24;
 175                 for (j = 0; j < 8; j++)
 176                 {
 177                         if (crc & 0x80000000)
 178                                 crc = (crc << 1) ^ QUOTIENT;
 179                         else
 180                                 crc = crc << 1;
 181                 }
 182                 gaiLink_CRCTable[i] = crc;
 183         }
 184
 185         gbLink_CRCTableGenerated = 1;
 186 }
 187
 188 Uint32 Link_CalculateCRC(tIPStackBuffer *Buffer)
 189 {
 190         Uint32  ret = 0xFFFFFFFF;
 191         const void      *data;
 192         size_t  length;
 193
 194          int    id = -1;
 195         while( (id = IPStack_Buffer_GetBuffer(Buffer, id, &length, &data)) != -1 )
 196         {
 197                 ret = Link_CalculatePartialCRC(ret, data, length);
 198         }
 199
 200         return ~ret;
 201 }
 202
 203 Uint32 Link_CalculatePartialCRC(Uint32 CRC, const void *Data, int Length)
 204 {
 205         // x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1
 206         const Uint32    *data = Data;
 207
 208         for( int i = 0; i < Length/4; i++ )
 209         {
 210                 CRC = (CRC << 8 | *data++) ^ gaiLink_CRCTable[CRC >> 24];
 211         }
 212
 213         return CRC;
 214 }