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STA OBSS: Add check for overlapping BSSs

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In the previous implementation connected STA performs OBSS scan
according to requests from its 20/40 MHz AP. However STA checks only 40
MHz intolerance subfield from HT Capabilities element in scan results.
Meanwhile, as per IEEE Std 802.11-2016, 11.16.12, STA should check
overlapping BSSs as well.

Note that all the required code to check overlapping BSSs did already
exist for AP mode since AP does those checks properly before operating
as 20/40 MHz BSS in the 2.4 GHz band. Use that existing code by replace
existing 40 MHz intolerance check in sme_proc_obss_scan() with the new
shared helper function check_bss_coex_40mhz().

Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
This commit is contained in:
Sergey Matyukevich 2019-03-19 12:35:56 +00:00 committed by Jouni Malinen
parent 3af78a4e04
commit 3204795d7a
3 changed files with 34 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
wpa_supplicant/events.c
View file

@ -1921,7 +1921,7 @@ static int _wpa_supplicant_event_scan_results(struct wpa_supplicant *wpa_s,
if (wnm_scan_process(wpa_s, 1) > 0)
goto scan_work_done;
if (sme_proc_obss_scan(wpa_s) > 0)
if (sme_proc_obss_scan(wpa_s, scan_res) > 0)
goto scan_work_done;
if (own_request && data &&

42
wpa_supplicant/sme.c
View file

@ -13,6 +13,7 @@
#include "common/ieee802_11_defs.h"
#include "common/ieee802_11_common.h"
#include "common/ocv.h"
#include "common/hw_features_common.h"
#include "eapol_supp/eapol_supp_sm.h"
#include "common/wpa_common.h"
#include "common/sae.h"
@ -2214,13 +2215,14 @@ static void sme_send_2040_bss_coex(struct wpa_supplicant *wpa_s,
}
int sme_proc_obss_scan(struct wpa_supplicant *wpa_s)
int sme_proc_obss_scan(struct wpa_supplicant *wpa_s,
struct wpa_scan_results *scan_res)
{
struct wpa_bss *bss;
const u8 *ie;
u16 ht_cap;
u8 chan_list[P2P_MAX_CHANNELS], channel;
u8 num_channels = 0, num_intol = 0, i;
size_t j;
int pri_freq, sec_freq;
if (!wpa_s->sme.sched_obss_scan)
return 0;
@ -2248,22 +2250,36 @@ int sme_proc_obss_scan(struct wpa_supplicant *wpa_s)
os_memset(chan_list, 0, sizeof(chan_list));
dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
/* Skip other band bss */
pri_freq = wpa_s->assoc_freq;
switch (wpa_s->sme.ht_sec_chan) {
case HT_SEC_CHAN_ABOVE:
sec_freq = pri_freq + 20;
break;
case HT_SEC_CHAN_BELOW:
sec_freq = pri_freq - 20;
break;
case HT_SEC_CHAN_UNKNOWN:
default:
wpa_msg(wpa_s, MSG_WARNING,
"Undefined secondary channel: drop OBSS scan results");
return 1;
}
for (j = 0; j < scan_res->num; j++) {
struct wpa_scan_res *bss = scan_res->res[j];
enum hostapd_hw_mode mode;
int res;
/* Skip other band bss */
mode = ieee80211_freq_to_chan(bss->freq, &channel);
if (mode != HOSTAPD_MODE_IEEE80211G &&
mode != HOSTAPD_MODE_IEEE80211B)
continue;
ie = wpa_bss_get_ie(bss, WLAN_EID_HT_CAP);
ht_cap = (ie && (ie[1] == 26)) ? WPA_GET_LE16(ie + 2) : 0;
wpa_printf(MSG_DEBUG, "SME OBSS scan BSS " MACSTR
" freq=%u chan=%u ht_cap=0x%x",
MAC2STR(bss->bssid), bss->freq, channel, ht_cap);
if (!ht_cap || (ht_cap & HT_CAP_INFO_40MHZ_INTOLERANT)) {
if (ht_cap & HT_CAP_INFO_40MHZ_INTOLERANT)
res = check_bss_coex_40mhz(bss, pri_freq, sec_freq);
if (res) {
if (res == 2)
num_intol++;
/* Check whether the channel is already considered */

6
wpa_supplicant/sme.h
View file

@ -37,7 +37,8 @@ void sme_disassoc_while_authenticating(struct wpa_supplicant *wpa_s,
void sme_clear_on_disassoc(struct wpa_supplicant *wpa_s);
void sme_deinit(struct wpa_supplicant *wpa_s);
int sme_proc_obss_scan(struct wpa_supplicant *wpa_s);
int sme_proc_obss_scan(struct wpa_supplicant *wpa_s,
struct wpa_scan_results *scan_res);
void sme_sched_obss_scan(struct wpa_supplicant *wpa_s, int enable);
void sme_external_auth_trigger(struct wpa_supplicant *wpa_s,
union wpa_event_data *data);
@ -112,7 +113,8 @@ static inline void sme_deinit(struct wpa_supplicant *wpa_s)
{
}
static inline int sme_proc_obss_scan(struct wpa_supplicant *wpa_s)
static inline int sme_proc_obss_scan(struct wpa_supplicant *wpa_s,
struct wpa_scan_results *scan_res)
{
return 0;
}