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) {
  43                         Warning("[NET  ] Out of heap space!");
  44                         return ;
  45                 }
  46                 i = giRegisteredTypes;
  47                 giRegisteredTypes ++;
  48                 gaRegisteredTypes = tmp;
  49         }
  50
  51         gaRegisteredTypes[i].Callback = Callback;
  52         gaRegisteredTypes[i].Type = Type;
  53 }
  54
  55 /**
  56  * \fn void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, int Length, void *Buffer)
  57  * \brief Formats and sends a packet on the specified interface
  58  */
  59 void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, int Length, void *Buffer)
  60 {
  61          int    bufSize = sizeof(tEthernetHeader) + Length;
  62         Uint8   buf[bufSize];
  63         tEthernetHeader *hdr = (void*)buf;
  64
  65         hdr->Dest = To;
  66         hdr->Src = Adapter->MacAddr;
  67         hdr->Type = htons(Type);
  68
  69         memcpy(hdr->Data, Buffer, Length);
  70
  71         VFS_Write(Adapter->DeviceFD, bufSize, buf);
  72 }
  73
  74 /**
  75  * \fn void Link_WatchDevice(tAdapter *Adapter)
  76  * \brief Spawns a worker thread to watch the specified adapter
  77  */
  78 void Link_WatchDevice(tAdapter *Adapter)
  79 {
  80          int    tid = Proc_SpawnWorker();       // Create a new worker thread
  81
  82         if(tid < 0) {
  83                 Warning("[NET  ] Unable to create watcher thread for '%s'", Adapter->Device);
  84                 return ;
  85         }
  86
  87         if(tid > 0) {
  88                 Log("[NET  ] Watching '%s' using tid %i", Adapter->Device, tid);
  89                 return ;
  90         }
  91
  92         // Child Thread
  93         while(Adapter->DeviceFD != -1)
  94         {
  95                 Uint8   buf[MAX_PACKET_SIZE];
  96                 tEthernetHeader *hdr = (void*)buf;
  97                  int    ret, i;
  98
  99                 // Wait for a packet (Read on a network device is blocking)
 100                 ret = VFS_Read(Adapter->DeviceFD, MAX_PACKET_SIZE, buf);
 101                 if(ret == -1)   break;
 102
 103                 if(ret <= sizeof(tEthernetHeader)) {
 104                         Log("[NET  ] Recieved an undersized packet");
 105                         continue;
 106                 }
 107
 108                 // Check if there is a registered callback for this packet type
 109                 for( i = giRegisteredTypes; i--; )
 110                 {
 111                         if(gaRegisteredTypes[i].Type == hdr->Type)      continue;
 112                 }
 113                 // No? Ignore it
 114                 if( i == -1 )   continue;
 115
 116                 // Call the callback
 117                 gaRegisteredTypes[i].Callback(
 118                         Adapter,
 119                         hdr->Src,
 120                         ret - sizeof(tEthernetHeader),
 121                         hdr->Data
 122                         );
 123         }
 124
 125         Log("[NET  ] Watcher terminated (file closed)");
 126 }