Very Computer

Im looking for a tutorial, or explanations on useing raw sockets to
send and receive raw ethernet packets on linux.

Ive found some example of the basics, but there are caveats to the
process that dont seem to be documented. For example, how to
get the interface index given the ethernet device name, whether the
socket needs to be in blocking/non-blocking mode, can I simply
stuff a socket buffer on an interfaces outgoing queue without useing
the socket functions, relevant ioctls, etc, etc.

If anyone has any information or knows where I can find a tutorial
on this, please let me know.

Thanks !

Mike

p.s. I need to send raw ethernet frames for a new protocol im
developing. IP/UDP/TCP packets just doesnt cut it in this case.

Have you tried just opening the device (/dev/eth0 or whatever) and
talking to it? You'll probably need to use ioctls to configure its
behavior and you'll probably still need to carefully prepare standard
packet headers.

NIC manufacturers don't, in general, seem very helpful in providing
information about their products.

You might gain useful information from reading the ethernet driver and
header file source code. I found "FAST Ethernet" by Liam B. Quinn and
Richard G. Russell to be an easy and worthwhile read. The IEEE ethernet
standard would be nice to have at hand (but probably would not be more
helpful than the Quinn/Russell book -- and it'd be much more costly to
buy.)

HTH
--
Morris Dovey
West Des Moines, Iowa USA
Available for embedded C contract work

The process is fairly straightforward:

open a packet socket
use an ioctl call to get the interface index
fill in the address struct (sockaddr_ll, I think)
make your packet
send it using sendto()

Wierd.

Quote:>You'll probably need to use ioctls to configure its behavior
>and you'll probably still need to carefully prepare standard
>packet headers.

Quote:>NIC manufacturers don't, in general, seem very helpful in
>providing information about their products.

$ man packet

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