[PATCH v2] hostapd: add Transmit Power Envelope IE

[Rajkumar Manoharan]

On Thu, Nov 26, 2015 at 09:03:22PM +0200, Jouni Malinen wrote:
> On Mon, Nov 23, 2015 at 06:40:26PM +0530, Rajkumar Manoharan wrote:
> > Add Transmit Power Envelope element defined in
> > IEEE P802.11-REVmc/D4.3, 8.4.2.161.
> 
> Thanks, applied.
>
> > diff --git a/src/ap/ieee802_11_vht.c b/src/ap/ieee802_11_vht.c
> > +u8 * hostapd_eid_vht_txpwr_env(struct hostapd_data *hapd, u8 *eid)
> 
> > +	max_tx_power = chan->max_tx_power - local_pwr_constraint;
> > +
> > +	/*
> > +	 * Local Maximum Transmit power is encoded as 2's complement
> > +	 * with a 0.5 dB step
> > +	 */
> > +	max_tx_power = ~(max_tx_power * 2) + 1;
> 
> Though, this does not look correct.. That would mess up positive values
> pretty badly. I think I fixed this, but anyway, please take a look at
> send a patch to update this, if needed.
>
your change looks much better that above logic. It also takes care of
special cases.

> > +	*eid++ = WLAN_EID_VHT_TRANSMIT_POWER_ENVELOPE;
> > +	*eid++ = 4;
> 
> That length value is not correct since this is now variable length:
> 
oops.. my bad.
> > +	/*
> > +	 * Max Transmit Power count and
> > +	 * Max Transmit Power units = 0 (EIRP)
> > +	 */
> > +	*eid++ = tx_pwr_count;
> > +
> > +	i = 0;
> > +	while (i++ <= tx_pwr_count)
> > +		*eid++ = max_tx_power;
> 
> Here.. Fixed the length field to match.
>
Sorry for the inconvenience.. Thanks a lot.

-Rajkumar