Making changes to 3c90X.c

Making changes to 3c90X.c

[Marcus Ramos]

Hello,

I am developing an application for which I need to make small changes to
the source code of 3c90x.c (3com ethernet driver). Indeed, I need to
access - and modify - the contents of the packets right before they are
sent on the wire. After examining sk_buff.h, function NICSendPacket of
3c90x.c and reading chapter 14 (Network Drivers) of the book Linux
Device Drivers, I concluded that SocketBuffer->data points to the first
octet of data in the packet.

My question is: can I access the contents of the buffer simply by

*(SocketBuffer->data)
*(SocketBuffer->data+1)
*(SocketBuffer->data+2) etc ?

What is the layout of the octets starting at data ? Eth header, IP
header, TCP header etc ,or ?

Can I write new contents back to the buffer the same way ?

Thanks in advance,
Marcus.