[Click] Alignment problem on ARM

[Roberto Riggio]

Hi,

I'll try to modify click-align.cc.

Could this issue be related to the fact that the interface that i'm using
is a wireless interface running in monitor mode (madwifi driver)?

I've realized that my simple router works fine with both Align 4 0  and
4 4. So there is a two bytes offeset that must be compensated.

R.

On 01/22/2010 03:26 PM, Cliff Frey wrote:
> If those numbers are correct, then yes.  So in this case the real 
> "problem" from click-align's perspective is that FromDevice is not 
> giving you packets that are (4 2) aligned.  You can work around this 
> problem any number of ways...  easiest for you to just make WifiDecap 
> give GeneratorAligner(4,2) in click-align.cc... perhaps a good long 
> term solution would be to make FromDevice support a configuration 
> argument that click-align.cc could use.  Also, on machines without 
> HAVE_INDIFFERENT_ALIGNMENT, fromdevice could actually verify the 
> alignment of packets received and warn if they are not at the correct 
> alignment.
>
> Cliff
>
> On Fri, Jan 22, 2010 at 1:47 AM, Roberto Riggio 
> <roberto.riggio at create-net.org <mailto:roberto.riggio at create-net.org>> 
> wrote:
>
>     On 01/22/2010 06:16 AM, Cliff Frey wrote:
>
>         Also, wifi_header + llc is probably more than 8 bytes...
>
>
>     Right, wifidecap pulls 26 + 8 bytes and pushes 14 bytes,
>     while athdescdecap pulls 32  bytes, which means that neither
>     of them is modifying the alignment. right?
>
>
>