BPF filtering?

Ian Caddy ianc at goanna.iinet.net.au
Wed Jul 13 02:13:41 UTC 2005

Hi Krystian,

Welcome to the world of RTEMS.

I haven't used BPF, and from a quick look into the 4.6.2 source, it is 
not implemented in the standard RTEMS port of the BSD stack.  The other 
thing is that the RTEMS port is of a slightly older vintage of the BSD 
stack than is current in FreeBSD.

The only support I can see is in:


which includes some definitions that are used by other parts of the code 
that were ported into RTEMS.

If this is the case, there won't be any examples in RTEMS of how to use 
it, sorry.


Ian Caddy

Krystian Lewandowski wrote:
> Hello,
> it's my first post on this list, so prepare for short introduction...
> my name is Krystian, i'm student and i'm writing document about RTEMS,
> now i think about dhcp server implementation as a practical example.
> Of course before i started writing from scratch i tried using ISC dhcpd
> (1.0.0 version, for its size and simplicity). And good news is that ISC
> dhcpd is prepared for NetBSD platform - inter alia, on which RTEMS is
> based. If you are interested with more detailed description, feel free
> writing to me. Now i can say only it doesn't work as i would expect,
> but it's beginning. And i don't know if i've got as much knowledge as it
> will be needed for running ISC dhcpd in RTEMS.
> But there is one thing, i want to ask - about Berkley Packet Filter in
> RTEMS. How i should use it with my app? Are there any examples?
> BPF is used in ISC dhcpd (you can see it more detailed here
> <http://lxr.citan.net/lxr/source/bpf.c?v=dhcp-1.0.0>).
> Only first step now:
> - creating socket:
>         sock = open ("/dev/bpf0", O_RDWR, 0);
> I will use RTEMS msdos fs implementation. But as i can see in sapi
> /dev/ implementation is independent from "userland" fs. This function
> call returns with error. Should i create /dev/bpfN file with
> O_CREAT - is it legal here? Maybe it should be created with
> rtems_io_register_name, included in Device_driver_table?
> And short questions - is writev or poll function call supported
> in RTEMS?
> --
> Sorry for my poor english.
> Pozdrowienia/Cheers
> Krystian Lewandowski <jid:citan at jabber.org>

Ian Caddy
Goanna Technologies Pty Ltd
+61 8 9221 1860

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