STA OBSS: Add check for overlapping BSSs

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>

diff --git a/wpa_supplicant/events.c b/wpa_supplicant/events.c
index 9d808c55dbc96701557785277c728708377a0bfe..f034e5040d7269d4e7b630b75cbf50de918caf8e 100644 (file)
--- a/wpa_supplicant/events.c
+++ b/wpa_supplicant/events.c
@@ -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 &&

diff --git a/wpa_supplicant/sme.c b/wpa_supplicant/sme.c
index 749802496fc61f4b420660ca0eecf796dec21a4b..08d7e3ece2d4f83f0c1f81ee38c755b46334ad82 100644 (file)
--- a/wpa_supplicant/sme.c
+++ b/wpa_supplicant/sme.c
@@ -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 */

diff --git a/wpa_supplicant/sme.h b/wpa_supplicant/sme.h
index 1a7f9e8320c749ae487bc7d748a7fc7ce2e5c32f..42d5a8317c7864570e9c53a5dca5e0b22253c614 100644 (file)
--- a/wpa_supplicant/sme.h
+++ b/wpa_supplicant/sme.h
@@ -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;
 }