+++ /dev/null
-/*
- * ACS - Automatic Channel Selection module
- * Copyright (c) 2011, Atheros Communications
- * 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 <math.h>
-
-#include "utils/common.h"
-#include "utils/list.h"
-#include "common/ieee802_11_defs.h"
-#include "common/wpa_ctrl.h"
-#include "drivers/driver.h"
-#include "hostapd.h"
-#include "ap_drv_ops.h"
-#include "ap_config.h"
-#include "hw_features.h"
-#include "acs.h"
-
-/*
- * Automatic Channel Selection
- * ===========================
- *
- * More info at
- * ------------
- * http://wireless.kernel.org/en/users/Documentation/acs
- *
- * How to use
- * ----------
- * - make sure you have CONFIG_ACS=y in hostapd's .config
- * - use channel=0 or channel=acs to enable ACS
- *
- * How does it work
- * ----------------
- * 1. passive scans are used to collect survey data
- * (it is assumed that scan trigger collection of survey data in driver)
- * 2. interference factor is calculated for each channel
- * 3. ideal channel is picked depending on channel width by using adjacent
- * channel interference factors
- *
- * Known limitations
- * -----------------
- * - Current implementation depends heavily on the amount of time willing to
- * spend gathering survey data during hostapd startup. Short traffic bursts
- * may be missed and a suboptimal channel may be picked.
- * - Ideal channel may end up overlapping a channel with 40 MHz intolerant BSS
- *
- * Todo / Ideas
- * ------------
- * - implement other interference computation methods
- * - BSS/RSSI based
- * - spectral scan based
- * (should be possibly to hook this up with current ACS scans)
- * - add wpa_supplicant support (for P2P)
- * - collect a histogram of interference over time allowing more educated
- * guess about an ideal channel (perhaps CSA could be used to migrate AP to a
- * new "better" channel while running)
- * - include neighboring BSS scan to avoid conflicts with 40 MHz intolerant BSSs
- * when choosing the ideal channel
- *
- * Survey interference factor implementation details
- * -------------------------------------------------
- * Generic interference_factor in struct hostapd_channel_data is used.
- *
- * The survey interference factor is defined as the ratio of the
- * observed busy time over the time we spent on the channel,
- * this value is then amplified by the observed noise floor on
- * the channel in comparison to the lowest noise floor observed
- * on the entire band.
- *
- * This corresponds to:
- * ---
- * (busy time - tx time) / (active time - tx time) * 2^(chan_nf + band_min_nf)
- * ---
- *
- * The coefficient of 2 reflects the way power in "far-field"
- * radiation decreases as the square of distance from the antenna [1].
- * What this does is it decreases the observed busy time ratio if the
- * noise observed was low but increases it if the noise was high,
- * proportionally to the way "far field" radiation changes over
- * distance.
- *
- * If channel busy time is not available the fallback is to use channel RX time.
- *
- * Since noise floor is in dBm it is necessary to convert it into Watts so that
- * combined channel interference (e.g., HT40, which uses two channels) can be
- * calculated easily.
- * ---
- * (busy time - tx time) / (active time - tx time) *
- * 2^(10^(chan_nf/10) + 10^(band_min_nf/10))
- * ---
- *
- * However to account for cases where busy/rx time is 0 (channel load is then
- * 0%) channel noise floor signal power is combined into the equation so a
- * channel with lower noise floor is preferred. The equation becomes:
- * ---
- * 10^(chan_nf/5) + (busy time - tx time) / (active time - tx time) *
- * 2^(10^(chan_nf/10) + 10^(band_min_nf/10))
- * ---
- *
- * All this "interference factor" is purely subjective and only time
- * will tell how usable this is. By using the minimum noise floor we
- * remove any possible issues due to card calibration. The computation
- * of the interference factor then is dependent on what the card itself
- * picks up as the minimum noise, not an actual real possible card
- * noise value.
- *
- * Total interference computation details
- * --------------------------------------
- * The above channel interference factor is calculated with no respect to
- * target operational bandwidth.
- *
- * To find an ideal channel the above data is combined by taking into account
- * the target operational bandwidth and selected band. E.g., on 2.4 GHz channels
- * overlap with 20 MHz bandwidth, but there is no overlap for 20 MHz bandwidth
- * on 5 GHz.
- *
- * Each valid and possible channel spec (i.e., channel + width) is taken and its
- * interference factor is computed by summing up interferences of each channel
- * it overlaps. The one with least total interference is picked up.
- *
- * Note: This implies base channel interference factor must be non-negative
- * allowing easy summing up.
- *
- * Example ACS analysis printout
- * -----------------------------
- *
- * ACS: Trying survey-based ACS
- * ACS: Survey analysis for channel 1 (2412 MHz)
- * ACS: 1: min_nf=-113 interference_factor=0.0802469 nf=-113 time=162 busy=0 rx=13
- * ACS: 2: min_nf=-113 interference_factor=0.0745342 nf=-113 time=161 busy=0 rx=12
- * ACS: 3: min_nf=-113 interference_factor=0.0679012 nf=-113 time=162 busy=0 rx=11
- * ACS: 4: min_nf=-113 interference_factor=0.0310559 nf=-113 time=161 busy=0 rx=5
- * ACS: 5: min_nf=-113 interference_factor=0.0248447 nf=-113 time=161 busy=0 rx=4
- * ACS: * interference factor average: 0.0557166
- * ACS: Survey analysis for channel 2 (2417 MHz)
- * ACS: 1: min_nf=-113 interference_factor=0.0185185 nf=-113 time=162 busy=0 rx=3
- * ACS: 2: min_nf=-113 interference_factor=0.0246914 nf=-113 time=162 busy=0 rx=4
- * ACS: 3: min_nf=-113 interference_factor=0.037037 nf=-113 time=162 busy=0 rx=6
- * ACS: 4: min_nf=-113 interference_factor=0.149068 nf=-113 time=161 busy=0 rx=24
- * ACS: 5: min_nf=-113 interference_factor=0.0248447 nf=-113 time=161 busy=0 rx=4
- * ACS: * interference factor average: 0.050832
- * ACS: Survey analysis for channel 3 (2422 MHz)
- * ACS: 1: min_nf=-113 interference_factor=2.51189e-23 nf=-113 time=162 busy=0 rx=0
- * ACS: 2: min_nf=-113 interference_factor=0.0185185 nf=-113 time=162 busy=0 rx=3
- * ACS: 3: min_nf=-113 interference_factor=0.0186335 nf=-113 time=161 busy=0 rx=3
- * ACS: 4: min_nf=-113 interference_factor=0.0186335 nf=-113 time=161 busy=0 rx=3
- * ACS: 5: min_nf=-113 interference_factor=0.0186335 nf=-113 time=161 busy=0 rx=3
- * ACS: * interference factor average: 0.0148838
- * ACS: Survey analysis for channel 4 (2427 MHz)
- * ACS: 1: min_nf=-114 interference_factor=1.58489e-23 nf=-114 time=162 busy=0 rx=0
- * ACS: 2: min_nf=-114 interference_factor=0.0555556 nf=-114 time=162 busy=0 rx=9
- * ACS: 3: min_nf=-114 interference_factor=1.58489e-23 nf=-114 time=161 busy=0 rx=0
- * ACS: 4: min_nf=-114 interference_factor=0.0186335 nf=-114 time=161 busy=0 rx=3
- * ACS: 5: min_nf=-114 interference_factor=0.00621118 nf=-114 time=161 busy=0 rx=1
- * ACS: * interference factor average: 0.0160801
- * ACS: Survey analysis for channel 5 (2432 MHz)
- * ACS: 1: min_nf=-114 interference_factor=0.409938 nf=-113 time=161 busy=0 rx=66
- * ACS: 2: min_nf=-114 interference_factor=0.0432099 nf=-113 time=162 busy=0 rx=7
- * ACS: 3: min_nf=-114 interference_factor=0.0124224 nf=-113 time=161 busy=0 rx=2
- * ACS: 4: min_nf=-114 interference_factor=0.677019 nf=-113 time=161 busy=0 rx=109
- * ACS: 5: min_nf=-114 interference_factor=0.0186335 nf=-114 time=161 busy=0 rx=3
- * ACS: * interference factor average: 0.232244
- * ACS: Survey analysis for channel 6 (2437 MHz)
- * ACS: 1: min_nf=-113 interference_factor=0.552795 nf=-113 time=161 busy=0 rx=89
- * ACS: 2: min_nf=-113 interference_factor=0.0807453 nf=-112 time=161 busy=0 rx=13
- * ACS: 3: min_nf=-113 interference_factor=0.0310559 nf=-113 time=161 busy=0 rx=5
- * ACS: 4: min_nf=-113 interference_factor=0.434783 nf=-112 time=161 busy=0 rx=70
- * ACS: 5: min_nf=-113 interference_factor=0.0621118 nf=-113 time=161 busy=0 rx=10
- * ACS: * interference factor average: 0.232298
- * ACS: Survey analysis for channel 7 (2442 MHz)
- * ACS: 1: min_nf=-113 interference_factor=0.440994 nf=-112 time=161 busy=0 rx=71
- * ACS: 2: min_nf=-113 interference_factor=0.385093 nf=-113 time=161 busy=0 rx=62
- * ACS: 3: min_nf=-113 interference_factor=0.0372671 nf=-113 time=161 busy=0 rx=6
- * ACS: 4: min_nf=-113 interference_factor=0.0372671 nf=-113 time=161 busy=0 rx=6
- * ACS: 5: min_nf=-113 interference_factor=0.0745342 nf=-113 time=161 busy=0 rx=12
- * ACS: * interference factor average: 0.195031
- * ACS: Survey analysis for channel 8 (2447 MHz)
- * ACS: 1: min_nf=-114 interference_factor=0.0496894 nf=-112 time=161 busy=0 rx=8
- * ACS: 2: min_nf=-114 interference_factor=0.0496894 nf=-114 time=161 busy=0 rx=8
- * ACS: 3: min_nf=-114 interference_factor=0.0372671 nf=-113 time=161 busy=0 rx=6
- * ACS: 4: min_nf=-114 interference_factor=0.12963 nf=-113 time=162 busy=0 rx=21
- * ACS: 5: min_nf=-114 interference_factor=0.166667 nf=-114 time=162 busy=0 rx=27
- * ACS: * interference factor average: 0.0865885
- * ACS: Survey analysis for channel 9 (2452 MHz)
- * ACS: 1: min_nf=-114 interference_factor=0.0124224 nf=-114 time=161 busy=0 rx=2
- * ACS: 2: min_nf=-114 interference_factor=0.0310559 nf=-114 time=161 busy=0 rx=5
- * ACS: 3: min_nf=-114 interference_factor=1.58489e-23 nf=-114 time=161 busy=0 rx=0
- * ACS: 4: min_nf=-114 interference_factor=0.00617284 nf=-114 time=162 busy=0 rx=1
- * ACS: 5: min_nf=-114 interference_factor=1.58489e-23 nf=-114 time=162 busy=0 rx=0
- * ACS: * interference factor average: 0.00993022
- * ACS: Survey analysis for channel 10 (2457 MHz)
- * ACS: 1: min_nf=-114 interference_factor=0.00621118 nf=-114 time=161 busy=0 rx=1
- * ACS: 2: min_nf=-114 interference_factor=0.00621118 nf=-114 time=161 busy=0 rx=1
- * ACS: 3: min_nf=-114 interference_factor=0.00621118 nf=-114 time=161 busy=0 rx=1
- * ACS: 4: min_nf=-114 interference_factor=0.0493827 nf=-114 time=162 busy=0 rx=8
- * ACS: 5: min_nf=-114 interference_factor=1.58489e-23 nf=-114 time=162 busy=0 rx=0
- * ACS: * interference factor average: 0.0136033
- * ACS: Survey analysis for channel 11 (2462 MHz)
- * ACS: 1: min_nf=-114 interference_factor=1.58489e-23 nf=-114 time=161 busy=0 rx=0
- * ACS: 2: min_nf=-114 interference_factor=2.51189e-23 nf=-113 time=161 busy=0 rx=0
- * ACS: 3: min_nf=-114 interference_factor=2.51189e-23 nf=-113 time=161 busy=0 rx=0
- * ACS: 4: min_nf=-114 interference_factor=0.0432099 nf=-114 time=162 busy=0 rx=7
- * ACS: 5: min_nf=-114 interference_factor=0.0925926 nf=-114 time=162 busy=0 rx=15
- * ACS: * interference factor average: 0.0271605
- * ACS: Survey analysis for channel 12 (2467 MHz)
- * ACS: 1: min_nf=-114 interference_factor=0.0621118 nf=-113 time=161 busy=0 rx=10
- * ACS: 2: min_nf=-114 interference_factor=0.00621118 nf=-114 time=161 busy=0 rx=1
- * ACS: 3: min_nf=-114 interference_factor=2.51189e-23 nf=-113 time=162 busy=0 rx=0
- * ACS: 4: min_nf=-114 interference_factor=2.51189e-23 nf=-113 time=162 busy=0 rx=0
- * ACS: 5: min_nf=-114 interference_factor=0.00617284 nf=-113 time=162 busy=0 rx=1
- * ACS: * interference factor average: 0.0148992
- * ACS: Survey analysis for channel 13 (2472 MHz)
- * ACS: 1: min_nf=-114 interference_factor=0.0745342 nf=-114 time=161 busy=0 rx=12
- * ACS: 2: min_nf=-114 interference_factor=0.0555556 nf=-114 time=162 busy=0 rx=9
- * ACS: 3: min_nf=-114 interference_factor=1.58489e-23 nf=-114 time=162 busy=0 rx=0
- * ACS: 4: min_nf=-114 interference_factor=1.58489e-23 nf=-114 time=162 busy=0 rx=0
- * ACS: 5: min_nf=-114 interference_factor=1.58489e-23 nf=-114 time=162 busy=0 rx=0
- * ACS: * interference factor average: 0.0260179
- * ACS: Survey analysis for selected bandwidth 20MHz
- * ACS: * channel 1: total interference = 0.121432
- * ACS: * channel 2: total interference = 0.137512
- * ACS: * channel 3: total interference = 0.369757
- * ACS: * channel 4: total interference = 0.546338
- * ACS: * channel 5: total interference = 0.690538
- * ACS: * channel 6: total interference = 0.762242
- * ACS: * channel 7: total interference = 0.756092
- * ACS: * channel 8: total interference = 0.537451
- * ACS: * channel 9: total interference = 0.332313
- * ACS: * channel 10: total interference = 0.152182
- * ACS: * channel 11: total interference = 0.0916111
- * ACS: * channel 12: total interference = 0.0816809
- * ACS: * channel 13: total interference = 0.0680776
- * ACS: Ideal channel is 13 (2472 MHz) with total interference factor of 0.0680776
- *
- * [1] http://en.wikipedia.org/wiki/Near_and_far_field
- */
-
-
-static int acs_request_scan(struct hostapd_iface *iface);
-static int acs_survey_is_sufficient(struct freq_survey *survey);
-
-
-static void acs_clean_chan_surveys(struct hostapd_channel_data *chan)
-{
- struct freq_survey *survey, *tmp;
-
- if (dl_list_empty(&chan->survey_list))
- return;
-
- dl_list_for_each_safe(survey, tmp, &chan->survey_list,
- struct freq_survey, list) {
- dl_list_del(&survey->list);
- os_free(survey);
- }
-}
-
-
-static void acs_cleanup(struct hostapd_iface *iface)
-{
- int i;
- struct hostapd_channel_data *chan;
-
- for (i = 0; i < iface->current_mode->num_channels; i++) {
- chan = &iface->current_mode->channels[i];
-
- if (chan->flag & HOSTAPD_CHAN_SURVEY_LIST_INITIALIZED)
- acs_clean_chan_surveys(chan);
-
- dl_list_init(&chan->survey_list);
- chan->flag |= HOSTAPD_CHAN_SURVEY_LIST_INITIALIZED;
- chan->min_nf = 0;
- }
-
- iface->chans_surveyed = 0;
- iface->acs_num_completed_scans = 0;
-}
-
-
-static void acs_fail(struct hostapd_iface *iface)
-{
- wpa_printf(MSG_ERROR, "ACS: Failed to start");
- acs_cleanup(iface);
- hostapd_disable_iface(iface);
-}
-
-
-static long double
-acs_survey_interference_factor(struct freq_survey *survey, s8 min_nf)
-{
- long double factor, busy, total;
-
- if (survey->filled & SURVEY_HAS_CHAN_TIME_BUSY)
- busy = survey->channel_time_busy;
- else if (survey->filled & SURVEY_HAS_CHAN_TIME_RX)
- busy = survey->channel_time_rx;
- else {
- /* This shouldn't really happen as survey data is checked in
- * acs_sanity_check() */
- wpa_printf(MSG_ERROR, "ACS: Survey data missing");
- return 0;
- }
-
- total = survey->channel_time;
-
- if (survey->filled & SURVEY_HAS_CHAN_TIME_TX) {
- busy -= survey->channel_time_tx;
- total -= survey->channel_time_tx;
- }
-
- /* TODO: figure out the best multiplier for noise floor base */
- factor = pow(10, survey->nf / 5.0L) +
- (busy / total) *
- pow(2, pow(10, (long double) survey->nf / 10.0L) -
- pow(10, (long double) min_nf / 10.0L));
-
- return factor;
-}
-
-
-static void
-acs_survey_chan_interference_factor(struct hostapd_iface *iface,
- struct hostapd_channel_data *chan)
-{
- struct freq_survey *survey;
- unsigned int i = 0;
- long double int_factor = 0;
- unsigned count = 0;
-
- if (dl_list_empty(&chan->survey_list))
- return;
-
- if (chan->flag & HOSTAPD_CHAN_DISABLED)
- return;
-
- chan->interference_factor = 0;
-
- dl_list_for_each(survey, &chan->survey_list, struct freq_survey, list)
- {
- i++;
-
- if (!acs_survey_is_sufficient(survey)) {
- wpa_printf(MSG_DEBUG, "ACS: %d: insufficient data", i);
- continue;
- }
-
- count++;
- int_factor = acs_survey_interference_factor(survey,
- iface->lowest_nf);
- chan->interference_factor += int_factor;
- wpa_printf(MSG_DEBUG, "ACS: %d: min_nf=%d interference_factor=%Lg nf=%d time=%lu busy=%lu rx=%lu",
- i, chan->min_nf, int_factor,
- survey->nf, (unsigned long) survey->channel_time,
- (unsigned long) survey->channel_time_busy,
- (unsigned long) survey->channel_time_rx);
- }
-
- if (!count)
- return;
- chan->interference_factor /= count;
-}
-
-
-static int acs_usable_ht40_chan(struct hostapd_channel_data *chan)
-{
- const int allowed[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 149,
- 157, 184, 192 };
- unsigned int i;
-
- for (i = 0; i < ARRAY_SIZE(allowed); i++)
- if (chan->chan == allowed[i])
- return 1;
-
- return 0;
-}
-
-
-static int acs_usable_vht80_chan(struct hostapd_channel_data *chan)
-{
- const int allowed[] = { 36, 52, 100, 116, 132, 149 };
- unsigned int i;
-
- for (i = 0; i < ARRAY_SIZE(allowed); i++)
- if (chan->chan == allowed[i])
- return 1;
-
- return 0;
-}
-
-
-static int acs_survey_is_sufficient(struct freq_survey *survey)
-{
- if (!(survey->filled & SURVEY_HAS_NF)) {
- wpa_printf(MSG_INFO, "ACS: Survey is missing noise floor");
- return 0;
- }
-
- if (!(survey->filled & SURVEY_HAS_CHAN_TIME)) {
- wpa_printf(MSG_INFO, "ACS: Survey is missing channel time");
- return 0;
- }
-
- if (!(survey->filled & SURVEY_HAS_CHAN_TIME_BUSY) &&
- !(survey->filled & SURVEY_HAS_CHAN_TIME_RX)) {
- wpa_printf(MSG_INFO,
- "ACS: Survey is missing RX and busy time (at least one is required)");
- return 0;
- }
-
- return 1;
-}
-
-
-static int acs_survey_list_is_sufficient(struct hostapd_channel_data *chan)
-{
- struct freq_survey *survey;
- int ret = -1;
-
- dl_list_for_each(survey, &chan->survey_list, struct freq_survey, list)
- {
- if (acs_survey_is_sufficient(survey)) {
- ret = 1;
- break;
- }
- ret = 0;
- }
-
- if (ret == -1)
- ret = 1; /* no survey list entries */
-
- if (!ret) {
- wpa_printf(MSG_INFO,
- "ACS: Channel %d has insufficient survey data",
- chan->chan);
- }
-
- return ret;
-}
-
-
-static int acs_surveys_are_sufficient(struct hostapd_iface *iface)
-{
- int i;
- struct hostapd_channel_data *chan;
- int valid = 0;
-
- for (i = 0; i < iface->current_mode->num_channels; i++) {
- chan = &iface->current_mode->channels[i];
- if (chan->flag & HOSTAPD_CHAN_DISABLED)
- continue;
-
- if (!acs_survey_list_is_sufficient(chan))
- continue;
-
- valid++;
- }
-
- /* We need at least survey data for one channel */
- return !!valid;
-}
-
-
-static int acs_usable_chan(struct hostapd_channel_data *chan)
-{
- if (dl_list_empty(&chan->survey_list))
- return 0;
- if (chan->flag & HOSTAPD_CHAN_DISABLED)
- return 0;
- if (!acs_survey_list_is_sufficient(chan))
- return 0;
- return 1;
-}
-
-
-static int is_in_chanlist(struct hostapd_iface *iface,
- struct hostapd_channel_data *chan)
-{
- if (!iface->conf->acs_ch_list.num)
- return 1;
-
- return freq_range_list_includes(&iface->conf->acs_ch_list, chan->chan);
-}
-
-
-static void acs_survey_all_chans_intereference_factor(
- struct hostapd_iface *iface)
-{
- int i;
- struct hostapd_channel_data *chan;
-
- for (i = 0; i < iface->current_mode->num_channels; i++) {
- chan = &iface->current_mode->channels[i];
-
- if (!acs_usable_chan(chan))
- continue;
-
- if (!is_in_chanlist(iface, chan))
- continue;
-
- wpa_printf(MSG_DEBUG, "ACS: Survey analysis for channel %d (%d MHz)",
- chan->chan, chan->freq);
-
- acs_survey_chan_interference_factor(iface, chan);
-
- wpa_printf(MSG_DEBUG, "ACS: * interference factor average: %Lg",
- chan->interference_factor);
- }
-}
-
-
-static struct hostapd_channel_data *acs_find_chan(struct hostapd_iface *iface,
- int freq)
-{
- struct hostapd_channel_data *chan;
- int i;
-
- for (i = 0; i < iface->current_mode->num_channels; i++) {
- chan = &iface->current_mode->channels[i];
-
- if (chan->flag & HOSTAPD_CHAN_DISABLED)
- continue;
-
- if (chan->freq == freq)
- return chan;
- }
-
- return NULL;
-}
-
-
-static int is_24ghz_mode(enum hostapd_hw_mode mode)
-{
- return mode == HOSTAPD_MODE_IEEE80211B ||
- mode == HOSTAPD_MODE_IEEE80211G;
-}
-
-
-static int is_common_24ghz_chan(int chan)
-{
- return chan == 1 || chan == 6 || chan == 11;
-}
-
-
-#ifndef ACS_ADJ_WEIGHT
-#define ACS_ADJ_WEIGHT 0.85
-#endif /* ACS_ADJ_WEIGHT */
-
-#ifndef ACS_NEXT_ADJ_WEIGHT
-#define ACS_NEXT_ADJ_WEIGHT 0.55
-#endif /* ACS_NEXT_ADJ_WEIGHT */
-
-#ifndef ACS_24GHZ_PREFER_1_6_11
-/*
- * Select commonly used channels 1, 6, 11 by default even if a neighboring
- * channel has a smaller interference factor as long as it is not better by more
- * than this multiplier.
- */
-#define ACS_24GHZ_PREFER_1_6_11 0.8
-#endif /* ACS_24GHZ_PREFER_1_6_11 */
-
-/*
- * At this point it's assumed chan->interface_factor has been computed.
- * This function should be reusable regardless of interference computation
- * option (survey, BSS, spectral, ...). chan->interference factor must be
- * summable (i.e., must be always greater than zero).
- */
-static struct hostapd_channel_data *
-acs_find_ideal_chan(struct hostapd_iface *iface)
-{
- struct hostapd_channel_data *chan, *adj_chan, *ideal_chan = NULL,
- *rand_chan = NULL;
- long double factor, ideal_factor = 0;
- int i, j;
- int n_chans = 1;
- unsigned int k;
-
- /* TODO: HT40- support */
-
- if (iface->conf->ieee80211n &&
- iface->conf->secondary_channel == -1) {
- wpa_printf(MSG_ERROR, "ACS: HT40- is not supported yet. Please try HT40+");
- return NULL;
- }
-
- if (iface->conf->ieee80211n &&
- iface->conf->secondary_channel)
- n_chans = 2;
-
- if (iface->conf->ieee80211ac &&
- iface->conf->vht_oper_chwidth == 1)
- n_chans = 4;
-
- /* TODO: VHT80+80, VHT160. Update acs_adjust_vht_center_freq() too. */
-
- wpa_printf(MSG_DEBUG, "ACS: Survey analysis for selected bandwidth %d MHz",
- n_chans == 1 ? 20 :
- n_chans == 2 ? 40 :
- 80);
-
- for (i = 0; i < iface->current_mode->num_channels; i++) {
- double total_weight;
- struct acs_bias *bias, tmp_bias;
-
- chan = &iface->current_mode->channels[i];
-
- if (chan->flag & HOSTAPD_CHAN_DISABLED)
- continue;
-
- if (!is_in_chanlist(iface, chan))
- continue;
-
- /* HT40 on 5 GHz has a limited set of primary channels as per
- * 11n Annex J */
- if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A &&
- iface->conf->ieee80211n &&
- iface->conf->secondary_channel &&
- !acs_usable_ht40_chan(chan)) {
- wpa_printf(MSG_DEBUG, "ACS: Channel %d: not allowed as primary channel for HT40",
- chan->chan);
- continue;
- }
-
- if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A &&
- iface->conf->ieee80211ac &&
- iface->conf->vht_oper_chwidth == 1 &&
- !acs_usable_vht80_chan(chan)) {
- wpa_printf(MSG_DEBUG, "ACS: Channel %d: not allowed as primary channel for VHT80",
- chan->chan);
- continue;
- }
-
- factor = 0;
- if (acs_usable_chan(chan))
- factor = chan->interference_factor;
- total_weight = 1;
-
- for (j = 1; j < n_chans; j++) {
- adj_chan = acs_find_chan(iface, chan->freq + (j * 20));
- if (!adj_chan)
- break;
-
- if (acs_usable_chan(adj_chan)) {
- factor += adj_chan->interference_factor;
- total_weight += 1;
- }
- }
-
- if (j != n_chans) {
- wpa_printf(MSG_DEBUG, "ACS: Channel %d: not enough bandwidth",
- chan->chan);
- continue;
- }
-
- /* 2.4 GHz has overlapping 20 MHz channels. Include adjacent
- * channel interference factor. */
- if (is_24ghz_mode(iface->current_mode->mode)) {
- for (j = 0; j < n_chans; j++) {
- adj_chan = acs_find_chan(iface, chan->freq +
- (j * 20) - 5);
- if (adj_chan && acs_usable_chan(adj_chan)) {
- factor += ACS_ADJ_WEIGHT *
- adj_chan->interference_factor;
- total_weight += ACS_ADJ_WEIGHT;
- }
-
- adj_chan = acs_find_chan(iface, chan->freq +
- (j * 20) - 10);
- if (adj_chan && acs_usable_chan(adj_chan)) {
- factor += ACS_NEXT_ADJ_WEIGHT *
- adj_chan->interference_factor;
- total_weight += ACS_NEXT_ADJ_WEIGHT;
- }
-
- adj_chan = acs_find_chan(iface, chan->freq +
- (j * 20) + 5);
- if (adj_chan && acs_usable_chan(adj_chan)) {
- factor += ACS_ADJ_WEIGHT *
- adj_chan->interference_factor;
- total_weight += ACS_ADJ_WEIGHT;
- }
-
- adj_chan = acs_find_chan(iface, chan->freq +
- (j * 20) + 10);
- if (adj_chan && acs_usable_chan(adj_chan)) {
- factor += ACS_NEXT_ADJ_WEIGHT *
- adj_chan->interference_factor;
- total_weight += ACS_NEXT_ADJ_WEIGHT;
- }
- }
- }
-
- factor /= total_weight;
-
- bias = NULL;
- if (iface->conf->acs_chan_bias) {
- for (k = 0; k < iface->conf->num_acs_chan_bias; k++) {
- bias = &iface->conf->acs_chan_bias[k];
- if (bias->channel == chan->chan)
- break;
- bias = NULL;
- }
- } else if (is_24ghz_mode(iface->current_mode->mode) &&
- is_common_24ghz_chan(chan->chan)) {
- tmp_bias.channel = chan->chan;
- tmp_bias.bias = ACS_24GHZ_PREFER_1_6_11;
- bias = &tmp_bias;
- }
-
- if (bias) {
- factor *= bias->bias;
- wpa_printf(MSG_DEBUG,
- "ACS: * channel %d: total interference = %Lg (%f bias)",
- chan->chan, factor, bias->bias);
- } else {
- wpa_printf(MSG_DEBUG,
- "ACS: * channel %d: total interference = %Lg",
- chan->chan, factor);
- }
-
- if (acs_usable_chan(chan) &&
- (!ideal_chan || factor < ideal_factor)) {
- ideal_factor = factor;
- ideal_chan = chan;
- }
-
- /* This channel would at least be usable */
- if (!rand_chan)
- rand_chan = chan;
- }
-
- if (ideal_chan) {
- wpa_printf(MSG_DEBUG, "ACS: Ideal channel is %d (%d MHz) with total interference factor of %Lg",
- ideal_chan->chan, ideal_chan->freq, ideal_factor);
- return ideal_chan;
- }
-
- return rand_chan;
-}
-
-
-static void acs_adjust_vht_center_freq(struct hostapd_iface *iface)
-{
- int offset;
-
- wpa_printf(MSG_DEBUG, "ACS: Adjusting VHT center frequency");
-
- switch (iface->conf->vht_oper_chwidth) {
- case VHT_CHANWIDTH_USE_HT:
- offset = 2 * iface->conf->secondary_channel;
- break;
- case VHT_CHANWIDTH_80MHZ:
- offset = 6;
- break;
- default:
- /* TODO: How can this be calculated? Adjust
- * acs_find_ideal_chan() */
- wpa_printf(MSG_INFO, "ACS: Only VHT20/40/80 is supported now");
- return;
- }
-
- iface->conf->vht_oper_centr_freq_seg0_idx =
- iface->conf->channel + offset;
-}
-
-
-static int acs_study_survey_based(struct hostapd_iface *iface)
-{
- wpa_printf(MSG_DEBUG, "ACS: Trying survey-based ACS");
-
- if (!iface->chans_surveyed) {
- wpa_printf(MSG_ERROR, "ACS: Unable to collect survey data");
- return -1;
- }
-
- if (!acs_surveys_are_sufficient(iface)) {
- wpa_printf(MSG_ERROR, "ACS: Surveys have insufficient data");
- return -1;
- }
-
- acs_survey_all_chans_intereference_factor(iface);
- return 0;
-}
-
-
-static int acs_study_options(struct hostapd_iface *iface)
-{
- int err;
-
- err = acs_study_survey_based(iface);
- if (err == 0)
- return 0;
-
- /* TODO: If no surveys are available/sufficient this is a good
- * place to fallback to BSS-based ACS */
-
- return -1;
-}
-
-
-static void acs_study(struct hostapd_iface *iface)
-{
- struct hostapd_channel_data *ideal_chan;
- int err;
-
- err = acs_study_options(iface);
- if (err < 0) {
- wpa_printf(MSG_ERROR, "ACS: All study options have failed");
- goto fail;
- }
-
- ideal_chan = acs_find_ideal_chan(iface);
- if (!ideal_chan) {
- wpa_printf(MSG_ERROR, "ACS: Failed to compute ideal channel");
- err = -1;
- goto fail;
- }
-
- iface->conf->channel = ideal_chan->chan;
-
- if (iface->conf->ieee80211ac)
- acs_adjust_vht_center_freq(iface);
-
- err = 0;
-fail:
- /*
- * hostapd_setup_interface_complete() will return -1 on failure,
- * 0 on success and 0 is HOSTAPD_CHAN_VALID :)
- */
- if (hostapd_acs_completed(iface, err) == HOSTAPD_CHAN_VALID) {
- acs_cleanup(iface);
- return;
- }
-
- /* This can possibly happen if channel parameters (secondary
- * channel, center frequencies) are misconfigured */
- wpa_printf(MSG_ERROR, "ACS: Possibly channel configuration is invalid, please report this along with your config file.");
- acs_fail(iface);
-}
-
-
-static void acs_scan_complete(struct hostapd_iface *iface)
-{
- int err;
-
- iface->scan_cb = NULL;
-
- wpa_printf(MSG_DEBUG, "ACS: Using survey based algorithm (acs_num_scans=%d)",
- iface->conf->acs_num_scans);
-
- err = hostapd_drv_get_survey(iface->bss[0], 0);
- if (err) {
- wpa_printf(MSG_ERROR, "ACS: Failed to get survey data");
- goto fail;
- }
-
- if (++iface->acs_num_completed_scans < iface->conf->acs_num_scans) {
- err = acs_request_scan(iface);
- if (err) {
- wpa_printf(MSG_ERROR, "ACS: Failed to request scan");
- goto fail;
- }
-
- return;
- }
-
- acs_study(iface);
- return;
-fail:
- hostapd_acs_completed(iface, 1);
- acs_fail(iface);
-}
-
-
-static int acs_request_scan(struct hostapd_iface *iface)
-{
- struct wpa_driver_scan_params params;
- struct hostapd_channel_data *chan;
- int i, *freq;
-
- os_memset(¶ms, 0, sizeof(params));
- params.freqs = os_calloc(iface->current_mode->num_channels + 1,
- sizeof(params.freqs[0]));
- if (params.freqs == NULL)
- return -1;
-
- freq = params.freqs;
- for (i = 0; i < iface->current_mode->num_channels; i++) {
- chan = &iface->current_mode->channels[i];
- if (chan->flag & HOSTAPD_CHAN_DISABLED)
- continue;
-
- if (!is_in_chanlist(iface, chan))
- continue;
-
- *freq++ = chan->freq;
- }
- *freq = 0;
-
- iface->scan_cb = acs_scan_complete;
-
- wpa_printf(MSG_DEBUG, "ACS: Scanning %d / %d",
- iface->acs_num_completed_scans + 1,
- iface->conf->acs_num_scans);
-
- if (hostapd_driver_scan(iface->bss[0], ¶ms) < 0) {
- wpa_printf(MSG_ERROR, "ACS: Failed to request initial scan");
- acs_cleanup(iface);
- os_free(params.freqs);
- return -1;
- }
-
- os_free(params.freqs);
- return 0;
-}
-
-
-enum hostapd_chan_status acs_init(struct hostapd_iface *iface)
-{
- int err;
-
- wpa_printf(MSG_INFO, "ACS: Automatic channel selection started, this may take a bit");
-
- if (iface->drv_flags & WPA_DRIVER_FLAGS_ACS_OFFLOAD) {
- wpa_printf(MSG_INFO, "ACS: Offloading to driver");
- err = hostapd_drv_do_acs(iface->bss[0]);
- if (err)
- return HOSTAPD_CHAN_INVALID;
- return HOSTAPD_CHAN_ACS;
- }
-
- if (!iface->current_mode)
- return HOSTAPD_CHAN_INVALID;
-
- acs_cleanup(iface);
-
- err = acs_request_scan(iface);
- if (err < 0)
- return HOSTAPD_CHAN_INVALID;
-
- hostapd_set_state(iface, HAPD_IFACE_ACS);
- wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, ACS_EVENT_STARTED);
-
- return HOSTAPD_CHAN_ACS;
-}
projects / mech_eap.git / blobdiff