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DFS: Allow skipping radar channels

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This is needed for AP CSA. Since CSA must happen immediately after radar
is detected there's no time to perform CAC. Thus, radar channels must be
disabled when looking for a new channel to escape to after a radar is
detected.

Signed-hostap: Michal Kazior <michal.kazior@tieto.com>
This commit is contained in:
Michal Kazior 2013-11-25 20:16:13 +01:00 committed by Jouni Malinen
parent 8d1fdde7f0
commit b72f949b07
1 changed files with 25 additions and 10 deletions
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35
src/ap/dfs.c
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@ -44,8 +44,17 @@ static int dfs_get_used_n_chans(struct hostapd_iface *iface)
}
static int dfs_channel_available(struct hostapd_channel_data *chan)
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.
*/
if (skip_radar && chan->flag & HOSTAPD_CHAN_RADAR)
return 0;
if (chan->flag & HOSTAPD_CHAN_DISABLED)
return 0;
if ((chan->flag & HOSTAPD_CHAN_RADAR) &&
@ -96,7 +105,8 @@ static int dfs_is_chan_allowed(struct hostapd_channel_data *chan, int n_chans)
static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
int first_chan_idx, int num_chans)
int first_chan_idx, int num_chans,
int skip_radar)
{
struct hostapd_channel_data *first_chan, *chan;
int i;
@ -112,7 +122,7 @@ static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
if (first_chan->freq + i * 20 != chan->freq)
return 0;
if (!dfs_channel_available(chan))
if (!dfs_channel_available(chan, skip_radar))
return 0;
}
@ -129,7 +139,7 @@ static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
*/
static int dfs_find_channel(struct hostapd_iface *iface,
struct hostapd_channel_data **ret_chan,
int idx)
int idx, int skip_radar)
{
struct hostapd_hw_modes *mode;
struct hostapd_channel_data *chan;
@ -149,7 +159,7 @@ static int dfs_find_channel(struct hostapd_iface *iface,
continue;
/* Skip incompatible chandefs */
if (!dfs_chan_range_available(mode, i, n_chans))
if (!dfs_chan_range_available(mode, i, n_chans, skip_radar))
continue;
if (ret_chan && idx == channel_idx) {
@ -322,7 +332,8 @@ static struct hostapd_channel_data *
dfs_get_valid_channel(struct hostapd_iface *iface,
int *secondary_channel,
u8 *vht_oper_centr_freq_seg0_idx,
u8 *vht_oper_centr_freq_seg1_idx)
u8 *vht_oper_centr_freq_seg1_idx,
int skip_radar)
{
struct hostapd_hw_modes *mode;
struct hostapd_channel_data *chan = NULL;
@ -340,13 +351,13 @@ dfs_get_valid_channel(struct hostapd_iface *iface,
return NULL;
/* Get the count first */
num_available_chandefs = dfs_find_channel(iface, NULL, 0);
num_available_chandefs = dfs_find_channel(iface, NULL, 0, skip_radar);
if (num_available_chandefs == 0)
return NULL;
os_get_random((u8 *) &_rand, sizeof(_rand));
chan_idx = _rand % num_available_chandefs;
dfs_find_channel(iface, &chan, chan_idx);
dfs_find_channel(iface, &chan, chan_idx, skip_radar);
/* dfs_find_channel() calculations assume HT40+ */
if (iface->conf->secondary_channel)
@ -518,6 +529,7 @@ int hostapd_handle_dfs(struct hostapd_iface *iface)
{
struct hostapd_channel_data *channel;
int res, n_chans, start_chan_idx;
int skip_radar = 0;
iface->cac_started = 0;
@ -555,7 +567,8 @@ int hostapd_handle_dfs(struct hostapd_iface *iface)
int sec;
u8 cf1, cf2;
channel = dfs_get_valid_channel(iface, &sec, &cf1, &cf2);
channel = dfs_get_valid_channel(iface, &sec, &cf1, &cf2,
skip_radar);
if (!channel) {
wpa_printf(MSG_ERROR, "could not get valid channel");
return -1;
@ -621,11 +634,13 @@ static int hostapd_dfs_start_channel_switch(struct hostapd_iface *iface)
int secondary_channel;
u8 vht_oper_centr_freq_seg0_idx;
u8 vht_oper_centr_freq_seg1_idx;
int skip_radar = 1;
wpa_printf(MSG_DEBUG, "%s called", __func__);
channel = dfs_get_valid_channel(iface, &secondary_channel,
&vht_oper_centr_freq_seg0_idx,
&vht_oper_centr_freq_seg1_idx);
&vht_oper_centr_freq_seg1_idx,
skip_radar);
if (channel) {
wpa_printf(MSG_DEBUG, "DFS will switch to a new channel %d",
channel->chan);