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Scan only affected frequencies for 20/40 MHz co-ex check for

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When starting an AP with HT40 on 2.4 GHz, limit the set of channels
to scan for based on the affected frequency range to speed up the
AP setup.

Signed-hostap: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2012-04-08 12:12:32 +03:00
parent 3208b5a0fe
commit 7fa56233ae
1 changed files with 46 additions and 3 deletions
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49
src/ap/hw_features.c
View file

@ -2,7 +2,7 @@
* hostapd / Hardware feature query and different modes * hostapd / Hardware feature query and different modes
* Copyright 2002-2003, Instant802 Networks, Inc. * Copyright 2002-2003, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc. * Copyright 2005-2006, Devicescape Software, Inc.
* Copyright (c) 2008-2011, Jouni Malinen <j@w1.fi> * Copyright (c) 2008-2012, Jouni Malinen <j@w1.fi>
* *
* This program is free software; you can redistribute it and/or modify * 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 * it under the terms of the GNU General Public License version 2 as
@ -416,7 +416,7 @@ static void ieee80211n_check_scan(struct hostapd_iface *iface)
int res; int res;
/* Check list of neighboring BSSes (from scan) to see whether 40 MHz is /* Check list of neighboring BSSes (from scan) to see whether 40 MHz is
* allowed per IEEE 802.11n/D7.0, 11.14.3.2 */ * allowed per IEEE Std 802.11-2012, 10.15.3.2 */
iface->scan_cb = NULL; iface->scan_cb = NULL;
@ -447,6 +447,46 @@ static void ieee80211n_check_scan(struct hostapd_iface *iface)
} }
static void ieee80211n_scan_channels_2g4(struct hostapd_iface *iface,
struct wpa_driver_scan_params *params)
{
/* Scan only the affected frequency range */
int pri_freq, sec_freq;
int affected_start, affected_end;
int i, pos;
struct hostapd_hw_modes *mode;
if (iface->current_mode == NULL)
return;
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);
mode = iface->current_mode;
params->freqs = os_zalloc((mode->num_channels + 1) * sizeof(int));
if (params->freqs == NULL)
return;
pos = 0;
for (i = 0; i < mode->num_channels; i++) {
struct hostapd_channel_data *chan = &mode->channels[i];
if (chan->flag & HOSTAPD_CHAN_DISABLED)
continue;
if (chan->freq < affected_start ||
chan->freq > affected_end)
continue;
params->freqs[pos++] = chan->freq;
}
}
static int ieee80211n_check_40mhz(struct hostapd_iface *iface) static int ieee80211n_check_40mhz(struct hostapd_iface *iface)
{ {
struct wpa_driver_scan_params params; struct wpa_driver_scan_params params;
@ -457,12 +497,15 @@ static int ieee80211n_check_40mhz(struct hostapd_iface *iface)
wpa_printf(MSG_DEBUG, "Scan for neighboring BSSes prior to enabling " wpa_printf(MSG_DEBUG, "Scan for neighboring BSSes prior to enabling "
"40 MHz channel"); "40 MHz channel");
os_memset(&params, 0, sizeof(params)); os_memset(&params, 0, sizeof(params));
/* TODO: scan only the needed frequency */ if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211G)
ieee80211n_scan_channels_2g4(iface, &params);
if (hostapd_driver_scan(iface->bss[0], &params) < 0) { if (hostapd_driver_scan(iface->bss[0], &params) < 0) {
wpa_printf(MSG_ERROR, "Failed to request a scan of " wpa_printf(MSG_ERROR, "Failed to request a scan of "
"neighboring BSSes"); "neighboring BSSes");
os_free(params.freqs);
return -1; return -1;
} }
os_free(params.freqs);
iface->scan_cb = ieee80211n_check_scan; iface->scan_cb = ieee80211n_check_scan;
return 1; return 1;