2 * Acess2 Networking Stack
3 * - By John Hodge (thePowersGang)
6 * - Ethernet/802.3 Handling code
11 #include "include/buffer.h"
12 #include "include/adapters_int.h"
15 #define LINK_LOGPACKETS 0
16 #define VALIDATE_CHECKSUM 0
17 #define MAX_PACKET_SIZE 2048
20 void Link_RegisterType(Uint16 Type, tPacketCallback Callback);
21 void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, tIPStackBuffer *Buffer);
22 int Link_HandlePacket(tAdapter *Adapter, tIPStackBuffer *Buffer);
24 void Link_InitCRC(void);
25 Uint32 Link_CalculateCRC(tIPStackBuffer *Buffer);
26 Uint32 Link_CalculatePartialCRC(Uint32 CRC, const void *Data, int Length);
29 int giRegisteredTypes = 0;
30 int giRegisteredTypeSpace = 0;
33 tPacketCallback Callback;
35 int gbLink_CRCTableGenerated = 0;
36 Uint32 gaiLink_CRCTable[256];
40 * \fn void Link_RegisterType(Uint16 Type, tPacketCallback Callback)
41 * \brief Registers a callback for a specific packet type
43 * \todo Make thread safe (place a mutex on the list)
45 void Link_RegisterType(Uint16 Type, tPacketCallback Callback)
50 for( i = giRegisteredTypes; i -- ; )
52 if(gaRegisteredTypes[i].Type == Type) {
53 Log_Warning("Net Link", "Attempt to register 0x%x twice", Type);
57 if(gaRegisteredTypes[i].Callback == NULL) break;
62 giRegisteredTypeSpace += 5;
63 tmp = realloc(gaRegisteredTypes, giRegisteredTypeSpace*sizeof(*gaRegisteredTypes));
65 Log_Warning("Net Link",
66 "Out of heap space! (Attempted to allocate %i)",
67 giRegisteredTypeSpace*sizeof(*gaRegisteredTypes)
71 gaRegisteredTypes = tmp;
72 i = giRegisteredTypes;
76 gaRegisteredTypes[i].Callback = Callback;
77 gaRegisteredTypes[i].Type = Type;
81 * \fn void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, int Length, void *Buffer)
82 * \brief Formats and sends a packet on the specified interface
84 void Link_SendPacket(tAdapter *Adapter, Uint16 Type, tMacAddr To, tIPStackBuffer *Buffer)
86 int length = IPStack_Buffer_GetLength(Buffer);
87 int ofs = (4 - (length & 3)) & 3;
88 Uint8 buf[sizeof(tEthernetHeader) + ofs + 4];
89 //Uint32 *checksum = (void*)(buf + sizeof(tEthernetHeader) + ofs);
90 tEthernetHeader *hdr = (void*)buf;
93 memcpy(&hdr->Src, Adapter->HWAddr, 6); // TODO: Remove hard coded 6
94 hdr->Type = htons(Type);
95 memset(hdr+1, 0, ofs+4); // zero padding and checksum
97 Log_Log("Net Link", "Sending %i bytes (Type 0x%x)"
98 " to %02x:%02x:%02x:%02x:%02x:%02x"
99 " from %02x:%02x:%02x:%02x:%02x:%02x",
101 To.B[0], To.B[1], To.B[2], To.B[3], To.B[4], To.B[5],
102 hdr->Src.B[0], hdr->Src.B[1], hdr->Src.B[2],
103 hdr->Src.B[3], hdr->Src.B[4], hdr->Src.B[5]
107 if( (Adapter->Type->Flags & ADAPTERFLAG_OFFLOAD_MAC) )
109 IPStack_Buffer_AppendSubBuffer(Buffer, sizeof(tEthernetHeader), ofs, hdr, NULL, NULL);
113 IPStack_Buffer_AppendSubBuffer(Buffer, sizeof(tEthernetHeader), ofs + 4, hdr, NULL, NULL);
114 *checksum = htonl( Link_CalculateCRC(Buffer) );
115 Log_Debug("Net Link", "Non-Offloaded: 0x%x, 0x%x", *checksum, ntohl(*checksum));
119 Adapter_SendPacket(Adapter, Buffer);
122 int Link_HandlePacket(tAdapter *Adapter, tIPStackBuffer *Buffer)
125 void *data = IPStack_Buffer_CompactBuffer(Buffer, &len);
127 tEthernetHeader *hdr = (void*)data;
129 if(len < sizeof(tEthernetHeader)) {
130 Log_Log("Net Link", "Recieved an undersized packet (%i < %i)",
131 len, sizeof(tEthernetHeader));
138 "Packet from %02x:%02x:%02x:%02x:%02x:%02x"
139 " to %02x:%02x:%02x:%02x:%02x:%02x (Type=%04x)",
140 hdr->Src.B[0], hdr->Src.B[1], hdr->Src.B[2],
141 hdr->Src.B[3], hdr->Src.B[4], hdr->Src.B[5],
142 hdr->Dest.B[0], hdr->Dest.B[1], hdr->Dest.B[2],
143 hdr->Dest.B[3], hdr->Dest.B[4], hdr->Dest.B[5],
148 #if VALIDATE_CHECKSUM
149 Uint32 checksum = *(Uint32*)(data + len + 4);
150 Log_Log("NET Link", "Checksum 0x%08x", checksum);
151 Uint32 calculated = Link_CalculateCRC(Buffer);
152 // TODO: Check checksum
155 // Check if there is a registered callback for this packet type
157 for( i = giRegisteredTypes; i--; )
159 if(gaRegisteredTypes[i].Type == ntohs(hdr->Type)) break;
163 Log_Log("Net Link", "Unregistered type 0x%x", ntohs(hdr->Type));
170 gaRegisteredTypes[i].Callback(
173 len - sizeof(tEthernetHeader),
182 // From http://www.cl.cam.ac.uk/research/srg/bluebook/21/crc/node6.html
183 #define QUOTIENT 0x04c11db7
184 void Link_InitCRC(void)
186 for( int i = 0; i < 256; i++ )
188 Uint32 crc = i << 24;
189 for( int j = 0; j < 8; j++ )
192 crc = (crc << 1) ^ QUOTIENT;
196 gaiLink_CRCTable[i] = crc;
199 gbLink_CRCTableGenerated = 1;
202 Uint32 Link_CalculateCRC(tIPStackBuffer *Buffer)
204 Uint32 ret = 0xFFFFFFFF;
209 while( (id = IPStack_Buffer_GetBuffer(Buffer, id, &length, &data)) != -1 )
211 ret = Link_CalculatePartialCRC(ret, data, length);
217 Uint32 Link_CalculatePartialCRC(Uint32 CRC, const void *Data, int Length)
219 // x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1
220 const Uint32 *data = Data;
222 for( int i = 0; i < Length/4; i++ )
224 CRC = (CRC << 8 | *data++) ^ gaiLink_CRCTable[CRC >> 24];