From 32595da6087f13a93ee9407ede279de06d431c23 Mon Sep 17 00:00:00 2001 From: Michal Kazior Date: Thu, 31 Oct 2013 14:46:09 +0200 Subject: [PATCH] DFS: Fix HT40/VHT calculation Decouple HT/VHT offset/center-freq calculations from channel lookup. This will be necessary for further improvements on the DFS codebase. Signed-hostap: Michal Kazior --- src/ap/dfs.c | 96 ++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 66 insertions(+), 30 deletions(-) diff --git a/src/ap/dfs.c b/src/ap/dfs.c index a30861fa8..6a16306c5 100644 --- a/src/ap/dfs.c +++ b/src/ap/dfs.c @@ -94,6 +94,13 @@ static int dfs_is_chan_allowed(struct hostapd_channel_data *chan, int n_chans) } +/* + * The function assumes HT40+ operation. + * Make sure to adjust the following variables after calling this: + * - hapd->secondary_channel + * - hapd->vht_oper_centr_freq_seg0_idx + * - hapd->vht_oper_centr_freq_seg1_idx + */ static int dfs_find_channel(struct hostapd_data *hapd, struct hostapd_channel_data **ret_chan, int idx) @@ -126,9 +133,6 @@ static int dfs_find_channel(struct hostapd_data *hapd, } if (j != n_chans) continue; - - /* Set HT40+ */ - hapd->iconf->secondary_channel = 1; } if (ret_chan && idx == channel_idx) { @@ -144,7 +148,9 @@ static int dfs_find_channel(struct hostapd_data *hapd, static void dfs_adjust_vht_center_freq(struct hostapd_data *hapd, - struct hostapd_channel_data *chan) + struct hostapd_channel_data *chan, + u8 *vht_oper_centr_freq_seg0_idx, + u8 *vht_oper_centr_freq_seg1_idx) { if (!hapd->iconf->ieee80211ac) return; @@ -152,31 +158,31 @@ static void dfs_adjust_vht_center_freq(struct hostapd_data *hapd, if (!chan) return; + *vht_oper_centr_freq_seg1_idx = 0; + switch (hapd->iconf->vht_oper_chwidth) { case VHT_CHANWIDTH_USE_HT: if (hapd->iconf->secondary_channel == 1) - hapd->iconf->vht_oper_centr_freq_seg0_idx = - chan->chan + 2; + *vht_oper_centr_freq_seg0_idx = chan->chan + 2; else if (hapd->iconf->secondary_channel == -1) - hapd->iconf->vht_oper_centr_freq_seg0_idx = - chan->chan - 2; + *vht_oper_centr_freq_seg0_idx = chan->chan - 2; else - hapd->iconf->vht_oper_centr_freq_seg0_idx = chan->chan; + *vht_oper_centr_freq_seg0_idx = chan->chan; break; case VHT_CHANWIDTH_80MHZ: - hapd->iconf->vht_oper_centr_freq_seg0_idx = chan->chan + 6; + *vht_oper_centr_freq_seg0_idx = chan->chan + 6; break; case VHT_CHANWIDTH_160MHZ: - hapd->iconf->vht_oper_centr_freq_seg0_idx = - chan->chan + 14; + *vht_oper_centr_freq_seg0_idx = chan->chan + 14; break; default: wpa_printf(MSG_INFO, "DFS only VHT20/40/80/160 is supported now"); break; } - wpa_printf(MSG_DEBUG, "DFS adjusting VHT center frequency: %d", - hapd->iconf->vht_oper_centr_freq_seg0_idx); + wpa_printf(MSG_DEBUG, "DFS adjusting VHT center frequency: %d, %d", + *vht_oper_centr_freq_seg0_idx, + *vht_oper_centr_freq_seg1_idx); } @@ -295,12 +301,16 @@ static int dfs_check_chans_unavailable(struct hostapd_data *hapd, } -static struct hostapd_channel_data * dfs_get_valid_channel( - struct hostapd_data *hapd) +static struct hostapd_channel_data * +dfs_get_valid_channel(struct hostapd_data *hapd, + int *secondary_channel, + u8 *vht_oper_centr_freq_seg0_idx, + u8 *vht_oper_centr_freq_seg1_idx) { struct hostapd_hw_modes *mode; struct hostapd_channel_data *chan = NULL; - int channel_idx, new_channel_idx; + int num_available_chandefs; + int chan_idx; u32 _rand; wpa_printf(MSG_DEBUG, "DFS: Selecting random channel"); @@ -312,16 +322,24 @@ static struct hostapd_channel_data * dfs_get_valid_channel( if (mode->mode != HOSTAPD_MODE_IEEE80211A) return NULL; - /* get random available channel */ - channel_idx = dfs_find_channel(hapd, NULL, 0); - if (channel_idx > 0) { - os_get_random((u8 *) &_rand, sizeof(_rand)); - new_channel_idx = _rand % channel_idx; - dfs_find_channel(hapd, &chan, new_channel_idx); - } + /* Get the count first */ + num_available_chandefs = dfs_find_channel(hapd, NULL, 0); + if (num_available_chandefs == 0) + return NULL; - /* VHT */ - dfs_adjust_vht_center_freq(hapd, chan); + os_get_random((u8 *) &_rand, sizeof(_rand)); + chan_idx = _rand % num_available_chandefs; + dfs_find_channel(hapd, &chan, chan_idx); + + /* dfs_find_channel() calculations assume HT40+ */ + if (hapd->iconf->secondary_channel) + *secondary_channel = 1; + else + *secondary_channel = 0; + + dfs_adjust_vht_center_freq(hapd, chan, + vht_oper_centr_freq_seg0_idx, + vht_oper_centr_freq_seg1_idx); return chan; } @@ -513,13 +531,20 @@ int hostapd_handle_dfs(struct hostapd_data *hapd) wpa_printf(MSG_DEBUG, "DFS %d chans unavailable - choose other channel: %s", res, res ? "yes": "no"); if (res) { - channel = dfs_get_valid_channel(hapd); + int sec; + u8 cf1, cf2; + + channel = dfs_get_valid_channel(hapd, &sec, &cf1, &cf2); if (!channel) { wpa_printf(MSG_ERROR, "could not get valid channel"); return -1; } - hapd->iconf->channel = channel->chan; + hapd->iface->freq = channel->freq; + hapd->iconf->channel = channel->chan; + hapd->iconf->secondary_channel = sec; + hapd->iconf->vht_oper_centr_freq_seg0_idx = cf1; + hapd->iconf->vht_oper_centr_freq_seg1_idx = cf2; } } while (res); @@ -563,13 +588,24 @@ static int hostapd_dfs_start_channel_switch(struct hostapd_data *hapd) { struct hostapd_channel_data *channel; int err = 1; + int secondary_channel; + u8 vht_oper_centr_freq_seg0_idx; + u8 vht_oper_centr_freq_seg1_idx; wpa_printf(MSG_DEBUG, "%s called", __func__); - channel = dfs_get_valid_channel(hapd); + channel = dfs_get_valid_channel(hapd, &secondary_channel, + &vht_oper_centr_freq_seg0_idx, + &vht_oper_centr_freq_seg1_idx); if (channel) { hapd->iconf->channel = channel->chan; - hapd->iface->freq = channel->freq; + hapd->iconf->secondary_channel = secondary_channel; + hapd->iconf->vht_oper_centr_freq_seg0_idx = + vht_oper_centr_freq_seg0_idx; + hapd->iconf->vht_oper_centr_freq_seg1_idx = + vht_oper_centr_freq_seg1_idx; err = 0; + } else { + wpa_printf(MSG_ERROR, "No valid channel available"); } if (!hapd->cac_started) {