Extract BSS coex 40 MHz check into a separate function

Move this implementation from check_40mhz_2g4() into a new helper
function check_bss_coex_40mhz function() so that it can be used in the
station mode case as well as the previously used AP mode case.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>

src/common/hw_features_common.c

@@ -279,12 +279,87 @@ static int check_20mhz_bss(struct wpa_scan_res *bss, int pri_freq, int start,
 }
 
 
+/*
+ * Returns:
+ * 0: no impact
+ * 1: overlapping BSS
+ * 2: overlapping BSS with 40 MHz intolerant advertisement
+ */
+int check_bss_coex_40mhz(struct wpa_scan_res *bss, int pri_freq, int sec_freq)
+{
+	int affected_start, affected_end;
+	struct ieee802_11_elems elems;
+	int pri_chan, sec_chan;
+	int pri = bss->freq;
+	int sec = pri;
+
+	if (pri_freq == sec_freq)
+		return 1;
+
+	affected_start = (pri_freq + sec_freq) / 2 - 25;
+	affected_end = (pri_freq + sec_freq) / 2 + 25;
+
+	/* Check for overlapping 20 MHz BSS */
+	if (check_20mhz_bss(bss, pri_freq, affected_start, affected_end)) {
+		wpa_printf(MSG_DEBUG, "Overlapping 20 MHz BSS is found");
+		return 1;
+	}
+
+	get_pri_sec_chan(bss, &pri_chan, &sec_chan);
+
+	if (sec_chan) {
+		if (sec_chan < pri_chan)
+			sec = pri - 20;
+		else
+			sec = pri + 20;
+	}
+
+	if ((pri < affected_start || pri > affected_end) &&
+	    (sec < affected_start || sec > affected_end))
+		return 0; /* not within affected channel range */
+
+	wpa_printf(MSG_DEBUG, "Neighboring BSS: " MACSTR
+		   " freq=%d pri=%d sec=%d",
+		   MAC2STR(bss->bssid), bss->freq, pri_chan, sec_chan);
+
+	if (sec_chan) {
+		if (pri_freq != pri || sec_freq != sec) {
+			wpa_printf(MSG_DEBUG,
+				   "40 MHz pri/sec mismatch with BSS "
+				   MACSTR
+				   " <%d,%d> (chan=%d%c) vs. <%d,%d>",
+				   MAC2STR(bss->bssid),
+				   pri, sec, pri_chan,
+				   sec > pri ? '+' : '-',
+				   pri_freq, sec_freq);
+			return 1;
+		}
+	}
+
+	ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems, 0);
+	if (elems.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 2;
+		}
+	}
+
+	return 0;
+}
+
+
 int check_40mhz_2g4(struct hostapd_hw_modes *mode,
 		    struct wpa_scan_results *scan_res, int pri_chan,
 		    int sec_chan)
 {
 	int pri_freq, sec_freq;
-	int affected_start, affected_end;
 	size_t i;
 
 	if (!mode || !scan_res || !pri_chan || !sec_chan ||
@@ -294,70 +369,12 @@ int check_40mhz_2g4(struct hostapd_hw_modes *mode,
 	pri_freq = hw_get_freq(mode, pri_chan);
 	sec_freq = hw_get_freq(mode, sec_chan);
 
-	affected_start = (pri_freq + sec_freq) / 2 - 25;
-	affected_end = (pri_freq + sec_freq) / 2 + 25;
 	wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
-		   affected_start, affected_end);
+		   (pri_freq + sec_freq) / 2 - 25,
+		   (pri_freq + sec_freq) / 2 + 25);
 	for (i = 0; i < scan_res->num; i++) {
-		struct wpa_scan_res *bss = scan_res->res[i];
+		if (check_bss_coex_40mhz(scan_res->res[i], pri_freq, sec_freq))
-		int pri = bss->freq;
-		int sec = pri;
-		struct ieee802_11_elems elems;
-
-		/* Check for overlapping 20 MHz BSS */
-		if (check_20mhz_bss(bss, pri_freq, affected_start,
-				    affected_end)) {
-			wpa_printf(MSG_DEBUG,
-				   "Overlapping 20 MHz BSS is found");
 			return 0;
-		}
-
-		get_pri_sec_chan(bss, &pri_chan, &sec_chan);
-
-		if (sec_chan) {
-			if (sec_chan < pri_chan)
-				sec = pri - 20;
-			else
-				sec = pri + 20;
-		}
-
-		if ((pri < affected_start || pri > affected_end) &&
-		    (sec < affected_start || sec > affected_end))
-			continue; /* not within affected channel range */
-
-		wpa_printf(MSG_DEBUG, "Neighboring BSS: " MACSTR
-			   " freq=%d pri=%d sec=%d",
-			   MAC2STR(bss->bssid), bss->freq, pri_chan, sec_chan);
-
-		if (sec_chan) {
-			if (pri_freq != pri || sec_freq != sec) {
-				wpa_printf(MSG_DEBUG,
-					   "40 MHz pri/sec mismatch with BSS "
-					   MACSTR
-					   " <%d,%d> (chan=%d%c) vs. <%d,%d>",
-					   MAC2STR(bss->bssid),
-					   pri, sec, pri_chan,
-					   sec > pri ? '+' : '-',
-					   pri_freq, sec_freq);
-				return 0;
-			}
-		}
-
-		ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems,
-				       0);
-		if (elems.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;

src/common/hw_features_common.h

@@ -29,6 +29,7 @@ void get_pri_sec_chan(struct wpa_scan_res *bss, int *pri_chan, int *sec_chan);
 int check_40mhz_5g(struct wpa_scan_results *scan_res,
 		   struct hostapd_channel_data *pri_chan,
 		   struct hostapd_channel_data *sec_chan);
+int check_bss_coex_40mhz(struct wpa_scan_res *bss, int pri_freq, int sec_freq);
 int check_40mhz_2g4(struct hostapd_hw_modes *mode,
 		    struct wpa_scan_results *scan_res, int pri_chan,
 		    int sec_chan);