Allow ACS channel list to be configured as frequencies (in MHz)

The channel numbers are duplicated between 2.4 GHz / 5 GHz bands and 6
GHz band. Hence, add support to configure a list of frequencies to ACS
(freqlist) instead of a list of channel numbers (chanlist). Also, both 5
GHz and 6 GHz channels are referred by HOSTAPD_MODE_IEEE80211A. The 6
GHz channels alone can be configured by using both mode and frequency
list.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

hostapd/config_file.c

@@ -3162,6 +3162,13 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 				   line);
 			return 1;
 		}
+	} else if (os_strcmp(buf, "freqlist") == 0) {
+		if (freq_range_list_parse(&conf->acs_freq_list, pos)) {
+			wpa_printf(MSG_ERROR, "Line %d: invalid frequency list",
+				   line);
+			return 1;
+		}
+		conf->acs_freq_list_present = 1;
 	} else if (os_strcmp(buf, "beacon_int") == 0) {
 		int val = atoi(pos);
 		/* MIB defines range as 1..65535, but very small values

hostapd/hostapd.conf

@@ -205,6 +205,14 @@ channel=1
 #chanlist=100 104 108 112 116
 #chanlist=1 6 11-13
 
+# Frequency list restriction. This option allows hostapd to select one of the
+# provided frequencies when a frequency should be automatically selected.
+# Frequency list can be provided as range using hyphen ('-') or individual
+# frequencies can be specified by comma (',') separated values
+# Default: all frequencies allowed in selected hw_mode
+#freqlist=2437,5945,5965
+#freqlist=2437,5985-6105
+
 # Exclude DFS channels from ACS
 # This option can be used to exclude all DFS channels from the ACS channel list
 # in cases where the driver supports DFS channels.

src/ap/ap_config.c

@@ -936,6 +936,7 @@ void hostapd_config_free(struct hostapd_config *conf)
 	os_free(conf->supported_rates);
 	os_free(conf->basic_rates);
 	os_free(conf->acs_ch_list.range);
+	os_free(conf->acs_freq_list.range);
 	os_free(conf->driver_params);
 #ifdef CONFIG_ACS
 	os_free(conf->acs_chan_bias);

src/ap/ap_config.h

@@ -882,6 +882,8 @@ struct hostapd_config {
 	u8 edmg_channel;
 	u8 acs;
 	struct wpa_freq_range_list acs_ch_list;
+	struct wpa_freq_range_list acs_freq_list;
+	u8 acs_freq_list_present;
 	int acs_exclude_dfs;
 	enum hostapd_hw_mode hw_mode; /* HOSTAPD_MODE_IEEE80211A, .. */
 	enum {

src/ap/ap_drv_ops.c

@@ -10,6 +10,7 @@
 
 #include "utils/common.h"
 #include "common/ieee802_11_defs.h"
+#include "common/ieee802_11_common.h"
 #include "common/hw_features_common.h"
 #include "wps/wps.h"
 #include "p2p/p2p.h"
@@ -855,10 +856,20 @@ static void hostapd_get_hw_mode_any_channels(struct hostapd_data *hapd,
 	for (i = 0; i < mode->num_channels; i++) {
 		struct hostapd_channel_data *chan = &mode->channels[i];
 
-		if ((acs_ch_list_all ||
-		     freq_range_list_includes(&hapd->iface->conf->acs_ch_list,
-					      chan->chan)) &&
-		    !(chan->flag & HOSTAPD_CHAN_DISABLED) &&
+		if (!acs_ch_list_all &&
+		    (hapd->iface->conf->acs_freq_list.num &&
+		     !freq_range_list_includes(
+			     &hapd->iface->conf->acs_freq_list,
+			     chan->freq)))
+			continue;
+		if (!acs_ch_list_all &&
+		    (!hapd->iface->conf->acs_freq_list_present &&
+		     hapd->iface->conf->acs_ch_list.num &&
+		     !freq_range_list_includes(
+			     &hapd->iface->conf->acs_ch_list,
+			     chan->chan)))
+			continue;
+		if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
 		    !(hapd->iface->conf->acs_exclude_dfs &&
 		      (chan->flag & HOSTAPD_CHAN_RADAR)))
 			int_array_add_unique(freq_list, chan->freq);
@@ -898,8 +909,10 @@ int hostapd_drv_do_acs(struct hostapd_data *hapd)
 	 * If no chanlist config parameter is provided, include all enabled
 	 * channels of the selected hw_mode.
 	 */
-	if (!hapd->iface->conf->acs_ch_list.num)
-		acs_ch_list_all = 1;
+	if (hapd->iface->conf->acs_freq_list_present)
+		acs_ch_list_all = !hapd->iface->conf->acs_freq_list.num;
+	else
+		acs_ch_list_all = !hapd->iface->conf->acs_ch_list.num;
 
 	if (hapd->iface->current_mode)
 		selected_mode = hapd->iface->current_mode->mode;