hw_features.c

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/*
 * hostapd / Hardware feature query and different modes
 * Copyright 2002-2003, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright (c) 2008-2009, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "utils/includes.h"

#include "utils/common.h"
#include "utils/eloop.h"
#include "common/ieee802_11_defs.h"
#include "common/ieee802_11_common.h"
#include "drivers/driver.h"
#include "hostapd.h"
#include "ap_config.h"
#include "ap_drv_ops.h"
#include "hw_features.h"


void hostapd_free_hw_features(struct hostapd_hw_modes *hw_features,
                              size_t num_hw_features)
{
        size_t i;

        if (hw_features == NULL)
                return;

        for (i = 0; i < num_hw_features; i++) {
                os_free(hw_features[i].channels);
                os_free(hw_features[i].rates);
        }

        os_free(hw_features);
}


int hostapd_get_hw_features(struct hostapd_iface *iface)
{
        struct hostapd_data *hapd = iface->bss[0];
        int ret = 0, i, j;
        u16 num_modes, flags;
        struct hostapd_hw_modes *modes;

        if (hostapd_drv_none(hapd))
                return -1;
        modes = hostapd_get_hw_feature_data(hapd, &num_modes, &flags);
        if (modes == NULL) {
                hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
                               HOSTAPD_LEVEL_DEBUG,
                               "Fetching hardware channel/rate support not "
                               "supported.");
                return -1;
        }

        iface->hw_flags = flags;

        hostapd_free_hw_features(iface->hw_features, iface->num_hw_features);
        iface->hw_features = modes;
        iface->num_hw_features = num_modes;

        for (i = 0; i < num_modes; i++) {
                struct hostapd_hw_modes *feature = &modes[i];
                /* set flag for channels we can use in current regulatory
                 * domain */
                for (j = 0; j < feature->num_channels; j++) {
                        /*
                         * Disable all channels that are marked not to allow
                         * IBSS operation or active scanning. In addition,
                         * disable all channels that require radar detection,
                         * since that (in addition to full DFS) is not yet
                         * supported.
                         */
                        if (feature->channels[j].flag &
                            (HOSTAPD_CHAN_NO_IBSS |
                             HOSTAPD_CHAN_PASSIVE_SCAN |
                             HOSTAPD_CHAN_RADAR))
                                feature->channels[j].flag |=
                                        HOSTAPD_CHAN_DISABLED;
                        if (feature->channels[j].flag & HOSTAPD_CHAN_DISABLED)
                                continue;
                        wpa_printf(MSG_MSGDUMP, "Allowed channel: mode=%d "
                                   "chan=%d freq=%d MHz max_tx_power=%d dBm",
                                   feature->mode,
                                   feature->channels[j].chan,
                                   feature->channels[j].freq,
                                   feature->channels[j].max_tx_power);
                }
        }

        return ret;
}


static int hostapd_prepare_rates(struct hostapd_data *hapd,
                                 struct hostapd_hw_modes *mode)
{
        int i, num_basic_rates = 0;
        int basic_rates_a[] = { 60, 120, 240, -1 };
        int basic_rates_b[] = { 10, 20, -1 };
        int basic_rates_g[] = { 10, 20, 55, 110, -1 };
        int *basic_rates;

        if (hapd->iconf->basic_rates)
                basic_rates = hapd->iconf->basic_rates;
        else switch (mode->mode) {
        case HOSTAPD_MODE_IEEE80211A:
                basic_rates = basic_rates_a;
                break;
        case HOSTAPD_MODE_IEEE80211B:
                basic_rates = basic_rates_b;
                break;
        case HOSTAPD_MODE_IEEE80211G:
                basic_rates = basic_rates_g;
                break;
        default:
                return -1;
        }

        if (hostapd_set_rate_sets(hapd, hapd->iconf->supported_rates,
                                  basic_rates, mode->mode)) {
                wpa_printf(MSG_ERROR, "Failed to update rate sets in kernel "
                           "module");
        }

        os_free(hapd->iface->current_rates);
        hapd->iface->num_rates = 0;

        hapd->iface->current_rates =
                os_zalloc(mode->num_rates * sizeof(struct hostapd_rate_data));
        if (!hapd->iface->current_rates) {
                wpa_printf(MSG_ERROR, "Failed to allocate memory for rate "
                           "table.");
                return -1;
        }

        for (i = 0; i < mode->num_rates; i++) {
                struct hostapd_rate_data *rate;

                if (hapd->iconf->supported_rates &&
                    !hostapd_rate_found(hapd->iconf->supported_rates,
                                        mode->rates[i]))
                        continue;

                rate = &hapd->iface->current_rates[hapd->iface->num_rates];
                rate->rate = mode->rates[i];
                if (hostapd_rate_found(basic_rates, rate->rate)) {
                        rate->flags |= HOSTAPD_RATE_BASIC;
                        num_basic_rates++;
                }
                wpa_printf(MSG_DEBUG, "RATE[%d] rate=%d flags=0x%x",
                           hapd->iface->num_rates, rate->rate, rate->flags);
                hapd->iface->num_rates++;
        }

        if (hapd->iface->num_rates == 0 || num_basic_rates == 0) {
                wpa_printf(MSG_ERROR, "No rates remaining in supported/basic "
                           "rate sets (%d,%d).",
                           hapd->iface->num_rates, num_basic_rates);
                return -1;
        }

        return 0;
}


#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;

        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);

        /* 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 < sizeof(allowed) / sizeof(allowed[0]); 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;
}


static void ieee80211n_switch_pri_sec(struct hostapd_iface *iface)
{
        if (iface->conf->secondary_channel > 0) {
                iface->conf->channel += 4;
                iface->conf->secondary_channel = -1;
        } else {
                iface->conf->channel -= 4;
                iface->conf->secondary_channel = 1;
        }
}


static void ieee80211n_get_pri_sec_chan(struct wpa_scan_res *bss,
                                        int *pri_chan, int *sec_chan)
{
        struct ieee80211_ht_operation *oper;
        struct ieee802_11_elems elems;

        *pri_chan = *sec_chan = 0;

        ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems, 0);
        if (elems.ht_operation &&
            elems.ht_operation_len >= sizeof(*oper)) {
                oper = (struct ieee80211_ht_operation *) elems.ht_operation;
                *pri_chan = oper->control_chan;
                if (oper->ht_param & HT_INFO_HT_PARAM_REC_TRANS_CHNL_WIDTH) {
                        if (oper->ht_param &
                            HT_INFO_HT_PARAM_SECONDARY_CHNL_ABOVE)
                                *sec_chan = *pri_chan + 4;
                        else if (oper->ht_param &
                                 HT_INFO_HT_PARAM_SECONDARY_CHNL_BELOW)
                                *sec_chan = *pri_chan - 4;
                }
        }
}


static int ieee80211n_check_40mhz_5g(struct hostapd_iface *iface,
                                     struct wpa_scan_results *scan_res)
{
        int pri_chan, sec_chan, pri_freq, sec_freq, pri_bss, sec_bss;
        int bss_pri_chan, bss_sec_chan;
        size_t i;
        int match;

        pri_chan = iface->conf->channel;
        sec_chan = iface->conf->secondary_channel * 4;
        pri_freq = hostapd_hw_get_freq(iface->bss[0], pri_chan);
        if (iface->conf->secondary_channel > 0)
                sec_freq = pri_freq + 20;
        else
                sec_freq = pri_freq - 20;

        /*
         * Switch PRI/SEC channels if Beacons were detected on selected SEC
         * channel, but not on selected PRI channel.
         */
        pri_bss = sec_bss = 0;
        for (i = 0; i < scan_res->num; i++) {
                struct wpa_scan_res *bss = scan_res->res[i];
                if (bss->freq == pri_freq)
                        pri_bss++;
                else if (bss->freq == sec_freq)
                        sec_bss++;
        }
        if (sec_bss && !pri_bss) {
                wpa_printf(MSG_INFO, "Switch own primary and secondary "
                           "channel to get secondary channel with no Beacons "
                           "from other BSSes");
                ieee80211n_switch_pri_sec(iface);
        }

        /*
         * Match PRI/SEC channel with any existing HT40 BSS on the same
         * channels that we are about to use (if already mixed order in
         * existing BSSes, use own preference).
         */
        match = 0;
        for (i = 0; i < scan_res->num; i++) {
                struct wpa_scan_res *bss = scan_res->res[i];
                ieee80211n_get_pri_sec_chan(bss, &bss_pri_chan, &bss_sec_chan);
                if (pri_chan == bss_pri_chan &&
                    sec_chan == bss_sec_chan) {
                        match = 1;
                        break;
                }
        }
        if (!match) {
                for (i = 0; i < scan_res->num; i++) {
                        struct wpa_scan_res *bss = scan_res->res[i];
                        ieee80211n_get_pri_sec_chan(bss, &bss_pri_chan,
                                                    &bss_sec_chan);
                        if (pri_chan == bss_sec_chan &&
                            sec_chan == bss_pri_chan) {
                                wpa_printf(MSG_INFO, "Switch own primary and "
                                           "secondary channel due to BSS "
                                           "overlap with " MACSTR,
                                           MAC2STR(bss->bssid));
                                ieee80211n_switch_pri_sec(iface);
                                break;
                        }
                }
        }

        return 1;
}


static int ieee80211n_check_40mhz_2g4(struct hostapd_iface *iface,
                                      struct wpa_scan_results *scan_res)
{
        int pri_freq, sec_freq;
        int affected_start, affected_end;
        size_t i;

        pri_freq = hostapd_hw_get_freq(iface->bss[0], iface->conf->channel);
        if (iface->conf->secondary_channel > 0)
                sec_freq = pri_freq + 20;
        else
                sec_freq = pri_freq - 20;
        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);
        for (i = 0; i < scan_res->num; i++) {
                struct wpa_scan_res *bss = scan_res->res[i];
                int pri = bss->freq;
                int sec = pri;
                int sec_chan, pri_chan;

                ieee80211n_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;
                        }
                }

                /* TODO: 40 MHz intolerant */
        }

        return 1;
}


static void wpa_scan_results_free(struct wpa_scan_results *res)
{
        size_t i;

        if (res == NULL)
                return;

        for (i = 0; i < res->num; i++)
                os_free(res->res[i]);
        os_free(res->res);
        os_free(res);
}


static void ieee80211n_check_scan(struct hostapd_iface *iface)
{
        struct wpa_scan_results *scan_res;
        int oper40;

        /* Check list of neighboring BSSes (from scan) to see whether 40 MHz is
         * allowed per IEEE 802.11n/D7.0, 11.14.3.2 */

        iface->scan_cb = NULL;

        scan_res = hostapd_driver_get_scan_results(iface->bss[0]);
        if (scan_res == NULL) {
                hostapd_setup_interface_complete(iface, 1);
                return;
        }

        if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A)
                oper40 = ieee80211n_check_40mhz_5g(iface, scan_res);
        else
                oper40 = ieee80211n_check_40mhz_2g4(iface, scan_res);
        wpa_scan_results_free(scan_res);

        if (!oper40) {
                wpa_printf(MSG_INFO, "20/40 MHz operation not permitted on "
                           "channel pri=%d sec=%d based on overlapping BSSes",
                           iface->conf->channel,
                           iface->conf->channel +
                           iface->conf->secondary_channel * 4);
                iface->conf->secondary_channel = 0;
                iface->conf->ht_capab &= ~HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET;
        }

        hostapd_setup_interface_complete(iface, 0);
}


static int ieee80211n_check_40mhz(struct hostapd_iface *iface)
{
        struct wpa_driver_scan_params params;

        if (!iface->conf->secondary_channel)
                return 0; /* HT40 not used */

        wpa_printf(MSG_DEBUG, "Scan for neighboring BSSes prior to enabling "
                   "40 MHz channel");
        os_memset(&params, 0, sizeof(params));
        /* TODO: scan only the needed frequency */
        if (hostapd_driver_scan(iface->bss[0], &params) < 0) {
                wpa_printf(MSG_ERROR, "Failed to request a scan of "
                           "neighboring BSSes");
                return -1;
        }

        iface->scan_cb = ieee80211n_check_scan;
        return 1;
}


static int ieee80211n_supported_ht_capab(struct hostapd_iface *iface)
{
        u16 hw = iface->current_mode->ht_capab;
        u16 conf = iface->conf->ht_capab;

        if (!iface->conf->ieee80211n)
                return 1;

        if ((conf & HT_CAP_INFO_LDPC_CODING_CAP) &&
            !(hw & HT_CAP_INFO_LDPC_CODING_CAP)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [LDPC]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET) &&
            !(hw & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [HT40*]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_SMPS_MASK) != (hw & HT_CAP_INFO_SMPS_MASK) &&
            (conf & HT_CAP_INFO_SMPS_MASK) != HT_CAP_INFO_SMPS_DISABLED) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [SMPS-*]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_GREEN_FIELD) &&
            !(hw & HT_CAP_INFO_GREEN_FIELD)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [GF]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_SHORT_GI20MHZ) &&
            !(hw & HT_CAP_INFO_SHORT_GI20MHZ)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [SHORT-GI-20]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_SHORT_GI40MHZ) &&
            !(hw & HT_CAP_INFO_SHORT_GI40MHZ)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [SHORT-GI-40]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_TX_STBC) && !(hw & HT_CAP_INFO_TX_STBC)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [TX-STBC]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_RX_STBC_MASK) >
            (hw & HT_CAP_INFO_RX_STBC_MASK)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [RX-STBC*]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_DELAYED_BA) &&
            !(hw & HT_CAP_INFO_DELAYED_BA)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [DELAYED-BA]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_MAX_AMSDU_SIZE) &&
            !(hw & HT_CAP_INFO_MAX_AMSDU_SIZE)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [MAX-AMSDU-7935]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_DSSS_CCK40MHZ) &&
            !(hw & HT_CAP_INFO_DSSS_CCK40MHZ)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [DSSS_CCK-40]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_PSMP_SUPP) && !(hw & HT_CAP_INFO_PSMP_SUPP)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [PSMP]");
                return 0;
        }

        if ((conf & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT) &&
            !(hw & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT)) {
                wpa_printf(MSG_ERROR, "Driver does not support configured "
                           "HT capability [LSIG-TXOP-PROT]");
                return 0;
        }

        return 1;
}

#endif /* CONFIG_IEEE80211N */


int hostapd_check_ht_capab(struct hostapd_iface *iface)
{
#ifdef CONFIG_IEEE80211N
        int ret;
        ret = ieee80211n_check_40mhz(iface);
        if (ret)
                return ret;
        if (!ieee80211n_allowed_ht40_channel_pair(iface))
                return -1;
        if (!ieee80211n_supported_ht_capab(iface))
                return -1;
#endif /* CONFIG_IEEE80211N */

        return 0;
}


int hostapd_select_hw_mode(struct hostapd_iface *iface)
{
        int i, j, ok;

        if (iface->num_hw_features < 1)
                return -1;

        iface->current_mode = NULL;
        for (i = 0; i < iface->num_hw_features; i++) {
                struct hostapd_hw_modes *mode = &iface->hw_features[i];
                if (mode->mode == iface->conf->hw_mode) {
                        iface->current_mode = mode;
                        break;
                }
        }

        if (iface->current_mode == NULL) {
                wpa_printf(MSG_ERROR, "Hardware does not support configured "
                           "mode");
                hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
                               HOSTAPD_LEVEL_WARNING,
                               "Hardware does not support configured mode "
                               "(%d)", (int) iface->conf->hw_mode);
                return -1;
        }

        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 == iface->conf->channel)) {
                        ok = 1;
                        break;
                }
        }
        if (iface->conf->channel == 0) {
                /* TODO: could request a scan of neighboring BSSes and select
                 * the channel automatically */
                wpa_printf(MSG_ERROR, "Channel not configured "
                           "(hw_mode/channel in hostapd.conf)");
                return -1;
        }
        if (ok == 0 && iface->conf->channel != 0) {
                hostapd_logger(iface->bss[0], NULL,
                               HOSTAPD_MODULE_IEEE80211,
                               HOSTAPD_LEVEL_WARNING,
                               "Configured channel (%d) not found from the "
                               "channel list of current mode (%d) %s",
                               iface->conf->channel,
                               iface->current_mode->mode,
                               hostapd_hw_mode_txt(iface->current_mode->mode));
                iface->current_mode = NULL;
        }

        if (iface->current_mode == NULL) {
                hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
                               HOSTAPD_LEVEL_WARNING,
                               "Hardware does not support configured channel");
                return -1;
        }

        if (hostapd_prepare_rates(iface->bss[0], iface->current_mode)) {
                wpa_printf(MSG_ERROR, "Failed to prepare rates table.");
                hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
                                           HOSTAPD_LEVEL_WARNING,
                                           "Failed to prepare rates table.");
                return -1;
        }

        return 0;
}


const char * hostapd_hw_mode_txt(int mode)
{
        switch (mode) {
        case HOSTAPD_MODE_IEEE80211A:
                return "IEEE 802.11a";
        case HOSTAPD_MODE_IEEE80211B:
                return "IEEE 802.11b";
        case HOSTAPD_MODE_IEEE80211G:
                return "IEEE 802.11g";
        default:
                return "UNKNOWN";
        }
}


int hostapd_hw_get_freq(struct hostapd_data *hapd, int chan)
{
        int i;

        if (!hapd->iface->current_mode)
                return 0;

        for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
                struct hostapd_channel_data *ch =
                        &hapd->iface->current_mode->channels[i];
                if (ch->chan == chan)
                        return ch->freq;
        }

        return 0;
}


int hostapd_hw_get_channel(struct hostapd_data *hapd, int freq)
{
        int i;

        if (!hapd->iface->current_mode)
                return 0;

        for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
                struct hostapd_channel_data *ch =
                        &hapd->iface->current_mode->channels[i];
                if (ch->freq == freq)
                        return ch->chan;
        }

        return 0;
}