[rt2x00-users] Alignment, padding and IV/ICV

[Gertjan van Wingerde]

On 12/01/09 22:09, Benoit PAPILLAULT wrote:
> 
> OK. My feeling is that if we try to achieve header alignment + payload
> alignment + L2 pad at the same time, it will not work. For instance,
> with an ACK frame (header_length=10, l2pad=0), we cannot align both
> header + payload.

But an ACK frame won't have any payload, so no l2pad and no payload align (as
there is no payload).

> 
> If we align header for all frames + payload for data frame only, we then
> have :
> 
> - control frame : hdrlen = 16 so if we align header, payload will be
> align, except for ACK/CTS (hdrlen=10), which we don't care.
> - invalid frame : we don't care, no padding
> - data frame : if we align header+payload, L2pad will be OK as well
> (since hdrlen+l2pad is always a multiple of 4).
> - management frame : hdrlen=24, already multiple of 4. So alignment of
> header will also align the payload.
>