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  * \todo Make thread safe (place a mutex on the list)
  24  */
  25 void Link_RegisterType(Uint16 Type, tPacketCallback Callback)
  26 {
  27          int    i;
  28         void    *tmp;
  29         for( i = giRegisteredTypes; i -- ; )
  30         {
  31                 if(gaRegisteredTypes[i].Type == Type) {
  32                         Warning("[NET  ] Attempt to register 0x%x twice", Type);
  33                         return ;
  34                 }
  35                 // Ooh! Free slot!
  36                 if(gaRegisteredTypes[i].Callback == NULL)       break;
  37         }
  38
  39         if(i == -1)
  40         {
  41                 tmp = realloc(gaRegisteredTypes, (giRegisteredTypes+1)*sizeof(*gaRegisteredTypes));
  42                 if(!tmp)        Panic("[NET  ] Out of heap space!");
  43                 i = giRegisteredTypes;
  44                 giRegisteredTypes ++;
  45                 gaRegisteredTypes = tmp;
  46         }
  47
  48         gaRegisteredTypes[i].Callback = Callback;
  49         gaRegisteredTypes[i].Type = Type;
  50 }
  51
  52 /**
  53  * \fn void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, int Length, void *Buffer)
  54  * \brief Formats and sends a packet on the specified interface
  55  */
  56 void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, int Length, void *Buffer)
  57 {
  58          int    bufSize = sizeof(tEthernetHeader) + Length;
  59         Uint8   buf[bufSize];
  60         tEthernetHeader *hdr = (void*)buf;
  61
  62         hdr->Dest = To;
  63         hdr->Src = Adapter->MacAddr;
  64         hdr->Type = htons(Type);
  65
  66         memcpy(hdr->Data, Buffer, Length);
  67
  68         VFS_Write(Adapter->DeviceFD, bufSize, buf);
  69 }
  70
  71 /**
  72  * \fn void Link_WatchDevice(tAdapter *Adapter)
  73  * \brief Spawns a worker thread to watch the specified adapter
  74  */
  75 void Link_WatchDevice(tAdapter *Adapter)
  76 {
  77          int    tid = Proc_SpawnWorker();       // Create a new worker thread
  78
  79         if(tid < 0) {
  80                 Panic("[NET  ] Unable to create watcher thread for '%s'", Adapter->Device);
  81         }
  82
  83         if(tid > 0) {
  84                 Log("[NET  ] Watching '%s' using tid %i", Adapter->Device, tid);
  85                 return ;
  86         }
  87
  88         // Child Thread
  89         while(Adapter->DeviceFD != -1)
  90         {
  91                 Uint8   buf[MAX_PACKET_SIZE];
  92                 tEthernetHeader *hdr = (void*)buf;
  93                  int    ret, i;
  94
  95                 // Wait for a packet (Read on a network device is blocking)
  96                 ret = VFS_Read(Adapter->DeviceFD, MAX_PACKET_SIZE, buf);
  97                 if(ret == -1)   break;
  98
  99                 if(ret <= sizeof(tEthernetHeader)) {
 100                         Log("[NET  ] Recieved an undersized packet");
 101                         continue;
 102                 }
 103
 104                 // Check if there is a registered callback for this packet type
 105                 for( i = giRegisteredTypes; i--; )
 106                 {
 107                         if(gaRegisteredTypes[i].Type == hdr->Type)      continue;
 108                 }
 109                 // No? Ignore it
 110                 if( i == -1 )   continue;
 111
 112                 // Call the callback
 113                 gaRegisteredTypes[i].Callback(
 114                         Adapter,
 115                         hdr->Src,
 116                         ret - sizeof(tEthernetHeader),
 117                         hdr->Data
 118                         );
 119         }
 120
 121         Log("[NET  ] Watcher terminated (file closed)");
 122 }