[maybe spam] Re: linux PF_PACKET compatibility

[Da Rock]

On 02/13/11 06:15, Vlad Galu wrote:
>
>
> On Sat, Feb 12, 2011 at 12:28 PM, Da Rock 
> <freebsd-hackers at herveybayaustralia.com.au 
> <mailto:freebsd-hackers at herveybayaustralia.com.au>> wrote:
>
>     On 02/12/11 19:39, Gary Jennejohn wrote:
>
>         On Fri, 11 Feb 2011 17:19:17 -0800
>         Julian Elischer<julian at freebsd.org
>         <mailto:julian at freebsd.org>>  wrote:
>
>
>             On 2/11/11 4:03 PM, Da Rock wrote:
>
>                 Unfortunately this software uses this family instead
>                 of pcap or bpf.
>                 So when built it errors.
>
>                 I guess if I am to use this app I will have to rewrite
>                 the way it
>                 uses the network stack.
>
>             l2tp runs over UDP packets  (port 1701 (like the starship
>             enterprise))
>             I have no idea why they want raw packets.
>
>
>         Ther's a sendarp() routine which uses PF_PACKET to directly
>         access the
>         network driver and bypass the stack.  Lazy Linuxers who have
>         no idea
>         or don't care that other operating systems exist.
>
>
>     Indeed. Is it possible to leverage another compatible routine? I
>     haven't had a look yet as I just read the message, but can I
>     (after checking return values and arguments) just drop in another
>     arp routine? Or are they simply incompatible across the board?
>
>     From what I understand they should all be essentially doing the
>     same thing, but I could be wrong on this. Alternatively would I
>     have to basically rewrite the arp.c to be posix compatible (for
>     portability)?
>
>     Cheers
>
>
> You only need to rewrite the sendarp() routine, using a BPF device 
> descriptor instead of the PF_PACKET socket descriptor. Take a look at 
> libdnet[1] and rbootd[2]'s source.
>
> [1] http://libdnet.sf.net/
> [2] http://ftp.fr.openbsd.org/pub/OpenBSD/src/usr.sbin/rbootd/
>
> You will need, however, to fill the source with #ifdefs to compensate 
> the fact that Linux has assigned different names and sizes to the 
> members of struct ether_header and arphdr (and has a _BSD_SOURCE knob 
> to accomodate compiling BSD-based software)./ /
Ok, I think I know where I have this thing ass-backwards now: I was 
looking for similar structs with the same _size_- they don't have to be! 
Duh!

I've figured the out the members like ETH_ALEN and defined the bsd 
equivalent, I'll have to look into the _BSD_SOURCE.

Thx for the recorrect :)