From 03a72eacda5d9a1837a74387081596a0d5466ec1 Mon Sep 17 00:00:00 2001 From: Jouni Malinen Date: Thu, 17 Dec 2015 18:39:19 +0200 Subject: [PATCH] VHT: Add an interoperability workaround for 80+80 and 160 MHz channels Number of deployed 80 MHz capable VHT stations that do not support 80+80 and 160 MHz bandwidths seem to misbehave when trying to connect to an AP that advertises 80+80 or 160 MHz channel bandwidth in the VHT Operation element. To avoid such issues with deployed devices, modify the design based on newly proposed IEEE 802.11 standard changes. This allows poorly implemented VHT 80 MHz stations to connect with the AP in 80 MHz mode. 80+80 and 160 MHz capable stations need to support the new workaround mechanism to allow full bandwidth to be used. However, there are more or less no impacted station with 80+80/160 capability deployed. Signed-off-by: Jouni Malinen --- src/ap/ieee802_11_vht.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/src/ap/ieee802_11_vht.c b/src/ap/ieee802_11_vht.c index 3236016d5..08418980a 100644 --- a/src/ap/ieee802_11_vht.c +++ b/src/ap/ieee802_11_vht.c @@ -81,6 +81,26 @@ u8 * hostapd_eid_vht_operation(struct hostapd_data *hapd, u8 *eid) hapd->iconf->vht_oper_centr_freq_seg1_idx; oper->vht_op_info_chwidth = hapd->iconf->vht_oper_chwidth; + if (hapd->iconf->vht_oper_chwidth == 2) { + /* + * Convert 160 MHz channel width to new style as interop + * workaround. + */ + oper->vht_op_info_chwidth = 1; + oper->vht_op_info_chan_center_freq_seg1_idx = + oper->vht_op_info_chan_center_freq_seg0_idx; + if (hapd->iconf->channel < + hapd->iconf->vht_oper_centr_freq_seg0_idx) + oper->vht_op_info_chan_center_freq_seg0_idx -= 8; + else + oper->vht_op_info_chan_center_freq_seg0_idx += 8; + } else if (hapd->iconf->vht_oper_chwidth == 3) { + /* + * Convert 80+80 MHz channel width to new style as interop + * workaround. + */ + oper->vht_op_info_chwidth = 1; + } /* VHT Basic MCS set comes from hw */ /* Hard code 1 stream, MCS0-7 is a min Basic VHT MCS rates */