xref: /external/wpa_supplicant_8/wpa_supplicant/src/ap/dfs.c

/*
 * DFS - Dynamic Frequency Selection
 * Copyright (c) 2002-2013, Jouni Malinen <j@w1.fi>
 * Copyright (c) 2013, Qualcomm Atheros, Inc.
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "utils/includes.h"

#include "utils/common.h"
#include "common/ieee802_11_defs.h"
#include "common/wpa_ctrl.h"
#include "hostapd.h"
#include "ap_drv_ops.h"
#include "drivers/driver.h"
#include "dfs.h"


static int dfs_get_used_n_chans(struct hostapd_iface *iface, int *seg1)
{
	int n_chans = 1;

	*seg1 = 0;

	if (iface->conf->ieee80211n && iface->conf->secondary_channel)
		n_chans = 2;

	if (iface->conf->ieee80211ac) {
		switch (iface->conf->vht_oper_chwidth) {
		case VHT_CHANWIDTH_USE_HT:
			break;
		case VHT_CHANWIDTH_80MHZ:
			n_chans = 4;
			break;
		case VHT_CHANWIDTH_160MHZ:
			n_chans = 8;
			break;
		case VHT_CHANWIDTH_80P80MHZ:
			n_chans = 4;
			*seg1 = 4;
			break;
		default:
			break;
		}
	}

	return n_chans;
}


static int dfs_channel_available(struct hostapd_channel_data *chan,
				 int skip_radar)
{
	/*
	 * When radar detection happens, CSA is performed. However, there's no
	 * time for CAC, so radar channels must be skipped when finding a new
	 * channel for CSA, unless they are available for immediate use.
	 */
	if (skip_radar && (chan->flag & HOSTAPD_CHAN_RADAR) &&
	    ((chan->flag & HOSTAPD_CHAN_DFS_MASK) !=
	     HOSTAPD_CHAN_DFS_AVAILABLE))
		return 0;

	if (chan->flag & HOSTAPD_CHAN_DISABLED)
		return 0;
	if ((chan->flag & HOSTAPD_CHAN_RADAR) &&
	    ((chan->flag & HOSTAPD_CHAN_DFS_MASK) ==
	     HOSTAPD_CHAN_DFS_UNAVAILABLE))
		return 0;
	return 1;
}


static int dfs_is_chan_allowed(struct hostapd_channel_data *chan, int n_chans)
{
	/*
	 * The tables contain first valid channel number based on channel width.
	 * We will also choose this first channel as the control one.
	 */
	int allowed_40[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 149, 157,
			     184, 192 };
	/*
	 * VHT80, valid channels based on center frequency:
	 * 42, 58, 106, 122, 138, 155
	 */
	int allowed_80[] = { 36, 52, 100, 116, 132, 149 };
	/*
	 * VHT160 valid channels based on center frequency:
	 * 50, 114
	 */
	int allowed_160[] = { 36, 100 };
	int *allowed = allowed_40;
	unsigned int i, allowed_no = 0;

	switch (n_chans) {
	case 2:
		allowed = allowed_40;
		allowed_no = ARRAY_SIZE(allowed_40);
		break;
	case 4:
		allowed = allowed_80;
		allowed_no = ARRAY_SIZE(allowed_80);
		break;
	case 8:
		allowed = allowed_160;
		allowed_no = ARRAY_SIZE(allowed_160);
		break;
	default:
		wpa_printf(MSG_DEBUG, "Unknown width for %d channels", n_chans);
		break;
	}

	for (i = 0; i < allowed_no; i++) {
		if (chan->chan == allowed[i])
			return 1;
	}

	return 0;
}


static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
				    int first_chan_idx, int num_chans,
				    int skip_radar)
{
	struct hostapd_channel_data *first_chan, *chan;
	int i;

	if (first_chan_idx + num_chans >= mode->num_channels)
		return 0;

	first_chan = &mode->channels[first_chan_idx];

	for (i = 0; i < num_chans; i++) {
		chan = &mode->channels[first_chan_idx + i];

		if (first_chan->freq + i * 20 != chan->freq)
			return 0;

		if (!dfs_channel_available(chan, skip_radar))
			return 0;
	}

	return 1;
}


static int is_in_chanlist(struct hostapd_iface *iface,
			  struct hostapd_channel_data *chan)
{
	int *entry;

	if (!iface->conf->chanlist)
		return 1;

	for (entry = iface->conf->chanlist; *entry != -1; entry++) {
		if (*entry == chan->chan)
			return 1;
	}
	return 0;
}


/*