[RFC] hostapd: add VHT channel switch IEs

Rajkumar Manoharan rmanohar at qti.qualcomm.com
Wed Apr 22 08:23:01 EDT 2015


Add wide band channel switch and VHT tx power envelope IEs for
VHT bandwidth channel switch.

Signed-off-by: Rajkumar Manoharan <rmanohar at qti.qualcomm.com>
---
 src/ap/beacon.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/src/ap/beacon.c b/src/ap/beacon.c
index e575b65..4003a46 100644
--- a/src/ap/beacon.c
+++ b/src/ap/beacon.c
@@ -337,6 +337,72 @@ static u8 * hostapd_eid_secondary_channel(struct hostapd_data *hapd, u8 *eid)
 	return eid;
 }
 
+static u8 * hostapd_eid_wide_bw_chansw(struct hostapd_data *hapd, u8 *eid)
+{
+	struct hostapd_freq_params *params = &hapd->cs_freq_params;
+	u8 chan;
+
+	if (!params->freq)
+		return eid;
+
+	if (ieee80211_freq_to_chan(params->freq, &chan) ==
+	    NUM_HOSTAPD_MODES)
+		return eid;
+
+	*eid++ = WLAN_EID_VHT_WIDE_BW_CHSWITCH;
+	*eid++ = 3;
+
+	switch (params->bandwidth) {
+	case 40:
+		*eid++ = VHT_CHANWIDTH_USE_HT;
+		break;
+	case 80:
+		*eid++ = VHT_CHANWIDTH_80MHZ;
+		break;
+	case 160:
+		*eid++ = VHT_CHANWIDTH_160MHZ;
+		break;
+	}
+	*eid++ = params->freq + params->sec_channel_offset * 10;
+	*eid++ = params->center_freq2;
+
+	return eid;
+}
+
+static u8 * hostapd_eid_vht_txpwr_env(struct hostapd_data *hapd, u8 *eid)
+{
+	struct hostapd_freq_params *params = &hapd->cs_freq_params;
+	struct hostapd_hw_modes *mode = hapd->iface->current_mode;
+	struct hostapd_channel_data *chan;
+	int i;
+	u8 channel;
+
+	if (!params->freq)
+		return eid;
+
+	if (ieee80211_freq_to_chan(params->freq, &channel) ==
+	    NUM_HOSTAPD_MODES)
+		return eid;
+
+	for (i = 0; i < mode->num_channels; i++) {
+		if (mode->channels[i].freq == params->freq)
+			break;
+	}
+	if (i == mode->num_channels)
+		return eid;
+
+	chan = &mode->channels[i];
+
+	*eid++ = WLAN_EID_VHT_TRANSMIT_POWER_ENVELOPE;
+	*eid++ = 5;
+	*eid++ = 2;
+	*eid++ = chan->max_tx_power;
+	*eid++ = chan->max_tx_power;
+	*eid++ = chan->max_tx_power;
+	*eid++ = chan->max_tx_power;
+
+	return eid;
+}
 
 static u8 * hostapd_add_csa_elems(struct hostapd_data *hapd, u8 *pos,
 				  u8 *start, unsigned int *csa_counter_off)
@@ -354,6 +420,11 @@ static u8 * hostapd_add_csa_elems(struct hostapd_data *hapd, u8 *pos,
 		*csa_counter_off = pos - start - 1;
 		pos = hostapd_eid_secondary_channel(hapd, pos);
 	}
+	if (hapd->cs_freq_params.bandwidth > 20 &&
+	    hapd->cs_freq_params.vht_enabled) {
+		pos = hostapd_eid_wide_bw_chansw(hapd, pos);
+		pos = hostapd_eid_vht_txpwr_env(hapd, pos);
+	}
 
 	return pos;
 }
-- 
2.3.5



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