DGNum/hostapd
6
0
Fork 0
Code Issues Pull requests 1 Projects Releases Packages Wiki Activity Actions

hostapd: Extend support for HT 20/40 coexistence feature

Browse source 
Extend the minimal HT 20/40 co-ex support to include dynamic changes
during the lifetime of the BSS. If any STA connects to a 2.4 GHz AP with
40 MHz intolerant bit set then the AP will switch to 20 MHz operating
mode.

If for a period of time specified by OBSS delay factor and OBSS scan
interval AP does not have any information about 40 MHz intolerant STAs,
the BSS is switched from HT20 to HT40 mode.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
This commit is contained in:
Peng Xu 2014-04-14 20:40:56 +03:00 • committed by Jouni Malinen
parent 196c9c7cd2
commit 9c47f6a2a6
10 changed files with 140 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

34
src/ap/hw_features.c
View file

@ -19,6 +19,8 @@
#include "ap_config.h"
#include "ap_drv_ops.h"
#include "acs.h"
#include "ieee802_11.h"
#include "beacon.h"
#include "hw_features.h"
@ -414,6 +416,7 @@ static int ieee80211n_check_40mhz_2g4(struct hostapd_iface *iface,
int pri = bss->freq;
int sec = pri;
int sec_chan, pri_chan;
struct ieee802_11_elems elems;
ieee80211n_get_pri_sec_chan(bss, &pri_chan, &sec_chan);
@ -445,7 +448,23 @@ static int ieee80211n_check_40mhz_2g4(struct hostapd_iface *iface,
}
}
/* TODO: 40 MHz intolerant */
ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems,
0);
if (elems.ht_capabilities &&
elems.ht_capabilities_len >=
sizeof(struct ieee80211_ht_capabilities)) {
struct ieee80211_ht_capabilities *ht_cap =
(struct ieee80211_ht_capabilities *)
elems.ht_capabilities;
if (le_to_host16(ht_cap->ht_capabilities_info) &
HT_CAP_INFO_40MHZ_INTOLERANT) {
wpa_printf(MSG_DEBUG,
"40 MHz Intolerant is set on channel %d in BSS "
MACSTR, pri, MAC2STR(bss->bssid));
return 0;
}
}
}
return 1;
@ -475,6 +494,7 @@ static void ieee80211n_check_scan(struct hostapd_iface *iface)
oper40 = ieee80211n_check_40mhz_2g4(iface, scan_res);
wpa_scan_results_free(scan_res);
iface->secondary_ch = iface->conf->secondary_channel;
if (!oper40) {
wpa_printf(MSG_INFO, "20/40 MHz operation not permitted on "
"channel pri=%d sec=%d based on overlapping BSSes",
@ -482,9 +502,21 @@ static void ieee80211n_check_scan(struct hostapd_iface *iface)
iface->conf->channel +
iface->conf->secondary_channel * 4);
iface->conf->secondary_channel = 0;
if (iface->drv_flags & WPA_DRIVER_FLAGS_HT_2040_COEX) {
/*
* TODO: Could consider scheduling another scan to check
* if channel width can be changed if no coex reports
* are received from associating stations.
*/
}
}
res = ieee80211n_allowed_ht40_channel_pair(iface);
if (!res) {
iface->conf->secondary_channel = 0;
wpa_printf(MSG_INFO, "Fallback to 20 MHz");
}
hostapd_setup_interface_complete(iface, !res);
}