Re: Ethereal comparison 1.265 vs 1.270 DHCP Discover

[Bill Moss <bmoss clemson edu>]

I removed the first patch from dhcpcd.c and applied the patch to 
buildmsg.c. It works. Here is what ethereal shows

324 UDP data & PAD_STOP
 +8  UDP header
= 332 UDP total
     +20 IP header
= 352 UDPIP
 +14 Ethernet header
= 366 total

I tried

#define PAD_STOP        304

and it also works

304 UDP data & PAD_STOP
 +8  UDP header
= 312 UDP total
     +20 IP header
= 332 UDPIP
 +14 Ethernet header
= 346 total

This is where you were before you deep-sixed the client id stuff. I 
think 304 suffices. This has padded with 15 bytes over what you had 
before the patch.

I tried PAD_STOP 290 which is just a pad of 1 byte.

290 UDP data & PAD_STOP
 +8  UDP header
= 298 UDP total
     +20 IP header
= 318 UDPIP
 +14 Ethernet header
= 332 total

This did not work so it is more than just having even values for these 
various sizes.

Dan Williams wrote:

> Bill,
>
> Can you apply this patch to current CVS copy of NM?  It changes 
> dhcpcd/buildmsg.c only.  It now pads the  message to over 300 bytes and ensures 
> that the message is always an even number of bytes long.
>
> Thanks,
> Dan
>
> On Fri, 11 Feb 2005, Bill Moss wrote:
>
>  
>
> > I think older hardware may reject messages that are too short. The UDP 
> > part of the message contains a BOOTP section of options and there was a 
> > time when BOOTP messages had a minimize size of 300 bytes. If this is 
> > what the SMC is doing, the a message with a UDP part of 297 bytes will 
> > not pass muster. This is just a guess. I suppose you can pad the message 
> > one byte at a time and see where the boundary is. I am betting on 300 or 
> > 312.
> >
> > --
> > Bill Moss
> > Professor, Mathematical Sciences
> > Clemson University
> >
> > _______________________________________________
> > NetworkManager-list mailing list
> > NetworkManager-list gnome org
> > http://mail.gnome.org/mailman/listinfo/networkmanager-list
> >    

--
Bill Moss
Professor, Mathematical Sciences
Clemson University


--
Bill Moss
Professor, Mathematical Sciences
Clemson University