diff --git a/src/ap/hw_features.c b/src/ap/hw_features.c
index f17891b22..a76e63767 100644
--- a/src/ap/hw_features.c
+++ b/src/ap/hw_features.c
@@ -224,66 +224,16 @@ int hostapd_prepare_rates(struct hostapd_iface *iface,
 #ifdef CONFIG_IEEE80211N
 static int ieee80211n_allowed_ht40_channel_pair(struct hostapd_iface *iface)
 {
-	int sec_chan, ok, j, first;
-	int allowed[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 149, 157,
-			  184, 192 };
-	size_t k;
+	int pri_chan, sec_chan;
 
 	if (!iface->conf->secondary_channel)
 		return 1; /* HT40 not used */
 
-	sec_chan = iface->conf->channel + iface->conf->secondary_channel * 4;
-	wpa_printf(MSG_DEBUG, "HT40: control channel: %d  "
-		   "secondary channel: %d",
-		   iface->conf->channel, sec_chan);
+	pri_chan = iface->conf->channel;
+	sec_chan = pri_chan + iface->conf->secondary_channel * 4;
 
-	/* Verify that HT40 secondary channel is an allowed 20 MHz
-	 * channel */
-	ok = 0;
-	for (j = 0; j < iface->current_mode->num_channels; j++) {
-		struct hostapd_channel_data *chan =
-			&iface->current_mode->channels[j];
-		if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
-		    chan->chan == sec_chan) {
-			ok = 1;
-			break;
-		}
-	}
-	if (!ok) {
-		wpa_printf(MSG_ERROR, "HT40 secondary channel %d not allowed",
-			   sec_chan);
-		return 0;
-	}
-
-	/*
-	 * Verify that HT40 primary,secondary channel pair is allowed per
-	 * IEEE 802.11n Annex J. This is only needed for 5 GHz band since
-	 * 2.4 GHz rules allow all cases where the secondary channel fits into
-	 * the list of allowed channels (already checked above).
-	 */
-	if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211A)
-		return 1;
-
-	if (iface->conf->secondary_channel > 0)
-		first = iface->conf->channel;
-	else
-		first = sec_chan;
-
-	ok = 0;
-	for (k = 0; k < ARRAY_SIZE(allowed); k++) {
-		if (first == allowed[k]) {
-			ok = 1;
-			break;
-		}
-	}
-	if (!ok) {
-		wpa_printf(MSG_ERROR, "HT40 channel pair (%d, %d) not allowed",
-			   iface->conf->channel,
-			   iface->conf->secondary_channel);
-		return 0;
-	}
-
-	return 1;
+	return allowed_ht40_channel_pair(iface->current_mode, pri_chan,
+					 sec_chan);
 }
 
 
diff --git a/src/common/hw_features_common.c b/src/common/hw_features_common.c
index be2b83736..28ee16472 100644
--- a/src/common/hw_features_common.c
+++ b/src/common/hw_features_common.c
@@ -80,3 +80,63 @@ int hw_get_chan(struct hostapd_hw_modes *mode, int freq)
 
 	return chan;
 }
+
+
+int allowed_ht40_channel_pair(struct hostapd_hw_modes *mode, int pri_chan,
+			      int sec_chan)
+{
+	int ok, j, first;
+	int allowed[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 149, 157,
+			  184, 192 };
+	size_t k;
+
+	if (pri_chan == sec_chan || !sec_chan)
+		return 1; /* HT40 not used */
+
+	wpa_printf(MSG_DEBUG,
+		   "HT40: control channel: %d  secondary channel: %d",
+		   pri_chan, sec_chan);
+
+	/* Verify that HT40 secondary channel is an allowed 20 MHz
+	 * channel */
+	ok = 0;
+	for (j = 0; j < mode->num_channels; j++) {
+		struct hostapd_channel_data *chan = &mode->channels[j];
+		if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
+		    chan->chan == sec_chan) {
+			ok = 1;
+			break;
+		}
+	}
+	if (!ok) {
+		wpa_printf(MSG_ERROR, "HT40 secondary channel %d not allowed",
+			   sec_chan);
+		return 0;
+	}
+
+	/*
+	 * Verify that HT40 primary,secondary channel pair is allowed per
+	 * IEEE 802.11n Annex J. This is only needed for 5 GHz band since
+	 * 2.4 GHz rules allow all cases where the secondary channel fits into
+	 * the list of allowed channels (already checked above).
+	 */
+	if (mode->mode != HOSTAPD_MODE_IEEE80211A)
+		return 1;
+
+	first = pri_chan < sec_chan ? pri_chan : sec_chan;
+
+	ok = 0;
+	for (k = 0; k < ARRAY_SIZE(allowed); k++) {
+		if (first == allowed[k]) {
+			ok = 1;
+			break;
+		}
+	}
+	if (!ok) {
+		wpa_printf(MSG_ERROR, "HT40 channel pair (%d, %d) not allowed",
+			   pri_chan, sec_chan);
+		return 0;
+	}
+
+	return 1;
+}
diff --git a/src/common/hw_features_common.h b/src/common/hw_features_common.h
index 90d5f59f1..f4e86323e 100644
--- a/src/common/hw_features_common.h
+++ b/src/common/hw_features_common.h
@@ -20,4 +20,7 @@ struct hostapd_channel_data * hw_get_channel_freq(struct hostapd_hw_modes *mode,
 int hw_get_freq(struct hostapd_hw_modes *mode, int chan);
 int hw_get_chan(struct hostapd_hw_modes *mode, int freq);
 
+int allowed_ht40_channel_pair(struct hostapd_hw_modes *mode, int pri_chan,
+			      int sec_chan);
+
 #endif /* HW_FEATURES_COMMON_H */