Modules/IPStack/link.c

   1 /*
   2  * Acess2 IP Stack
   3  * - Link/Media Layer Interface
   4  */
   5 #include "ipstack.h"
   6 #include "link.h"
   7
   8 // === CONSTANTS ===
   9 #define MAX_PACKET_SIZE 2048
  10
  11 // === GLOBALS ===
  12  int    giRegisteredTypes = 0;
  13 struct {
  14         Uint16  Type;
  15         tPacketCallback Callback;
  16 }       *gaRegisteredTypes;
  17
  18 // === CODE ===
  19 /**
  20  * \fn void Link_RegisterType(Uint16 Type, tPacketCallback Callback)
  21  * \brief Registers a callback for a specific packet type
  22  */
  23 void Link_RegisterType(Uint16 Type, tPacketCallback Callback)
  24 {
  25          int    i;
  26         void    *tmp;
  27         for( i = giRegisteredTypes; i -- ; )
  28         {
  29                 if(gaRegisteredTypes[i].Type == Type) {
  30                         Warning("[NET  ] Attempt to register 0x%x twice", Type);
  31                         return ;
  32                 }
  33                 // Ooh! Free slot!
  34                 if(gaRegisteredTypes[i].Callback == NULL)       break;
  35         }
  36
  37         if(i + 1 == 0)
  38         {
  39                 tmp = realloc(gaRegisteredTypes, (giRegisteredTypes+1)*sizeof(*gaRegisteredTypes));
  40                 if(!tmp)        Panic("[NET  ] Out of heap space!");
  41                 i = giRegisteredTypes;
  42                 giRegisteredTypes ++;
  43                 gaRegisteredTypes = tmp;
  44         }
  45
  46         gaRegisteredTypes[i].Callback = Callback;
  47         gaRegisteredTypes[i].Type = Type;
  48 }
  49
  50 /**
  51  * \fn void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, int Length, void *Buffer)
  52  * \brief Formats and sends a packet on the specified interface
  53  */
  54 void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, int Length, void *Buffer)
  55 {
  56          int    bufSize = sizeof(tEthernetHeader) + Length;
  57         Uint8   buf[bufSize];
  58         tEthernetHeader *hdr = (void*)buf;
  59
  60         hdr->Dest = To;
  61         hdr->Src = Adapter->MacAddr;
  62         hdr->Type = htons(Type);
  63
  64         memcpy(hdr->Data, Buffer, Length);
  65
  66         VFS_Write(Adapter->DeviceFD, bufSize, buf);
  67 }
  68
  69 /**
  70  * \fn void Link_WatchDevice(tAdapter *Adapter)
  71  * \brief Spawns a worker thread to watch the specified adapter
  72  */
  73 void Link_WatchDevice(tAdapter *Adapter)
  74 {
  75          int    tid = Proc_SpawnWorker();       // Create a new worker thread
  76
  77         if(tid < 0) {
  78                 Panic("[NET  ] Unable to create watcher thread for '%s'", Adapter->Device);
  79         }
  80
  81         if(tid > 0) {
  82                 Log("[NET  ] Watching '%s' using tid %i", Adapter->Device, tid);
  83                 return ;
  84         }
  85
  86         // Child Thread
  87         while(Adapter->DeviceFD != -1)
  88         {
  89                 Uint8   buf[MAX_PACKET_SIZE];
  90                 tEthernetHeader *hdr = (void*)buf;
  91                  int    ret, i;
  92
  93                 // Wait for a packet
  94                 ret = VFS_Read(Adapter->DeviceFD, MAX_PACKET_SIZE, buf);
  95                 if(ret == -1)   break;
  96
  97                 if(ret <= sizeof(tEthernetHeader)) {
  98                         Log("[NET  ] Recieved an undersized packet");
  99                         continue;
 100                 }
 101
 102                 // Check if there is a registered callback for this packet type
 103                 for( i = giRegisteredTypes; i--; )
 104                 {
 105                         if(gaRegisteredTypes[i].Type == hdr->Type)      continue;
 106                 }
 107                 // No? Ignore it
 108                 if( i + 1 == 0 )        continue;
 109
 110                 // Call the callback
 111                 gaRegisteredTypes[i].Callback(
 112                         Adapter,
 113                         hdr->Src,
 114                         ret - sizeof(tEthernetHeader),
 115                         hdr->Data
 116                         );
 117         }
 118 }