ZealOS/src/Home/Net/Ethernet.CC

class CEthernetFrame
{
	U8	source_address[6];
	U8	padding[2];
	U8	destination_address[6];
	U16	ethertype;

	U8 *data;

	I64 length;
};

class CEthernetGlobals
{
	U8 ethernet_null[6];
	U8 ethernet_broadcast[6];

} ethernet_globals;

U0 EthernetInitGlobals()
{
	I64 i;
	for (i = 0; i < 6; i++)
	{
		ethernet_globals.ethernet_null[i]		= 0;
		ethernet_globals.ethernet_broadcast[i]	= 0xFF;
	}
}

//TODO: check length , figure out the length+4 
U0 EthernetFrameParse(CEthernetFrame *frame_out, U8 *frame, U16 length)
{
	//Shrine has a FIXME for check length! We need to figure out what
	//lengths are appropriate ...... Shrine also says MemCopy has a
	//high overhead. I'm almost tempted to say that means that a lot
	//of the current system should be done with less extra allocation
	//altogether, more passing.

	NetLog("ETHERNET FRAME PARSE: Parsing frame, copying out to frame_out param.");

	MemCopy(frame_out->destination_address, frame,						MAC_ADDRESS_LENGTH);

	MemCopy(frame_out->source_address,		frame + MAC_ADDRESS_LENGTH, MAC_ADDRESS_LENGTH);

	frame_out->ethertype = frame[ETHERNET_ETHERTYPE_OFFSET + 1] | (frame[ETHERNET_ETHERTYPE_OFFSET] << 8);

	frame_out->data		 = frame + ETHERNET_DATA_OFFSET;

	frame_out->length	 = length - ETHERNET_MAC_HEADER_LENGTH - 4;	// He has a comment literally just saying "??". + or - 4?
}

EthernetInitGlobals;