hostapd: Select any supported channel if ACS fails

Signed-hostap: Helmut Schaa <helmut.schaa@googlemail.com>

diff --git a/src/ap/acs.c b/src/ap/acs.c
index 05d0fa5647a3f2eece34e23480f774b95e53f969..8536e481a990d6724b4f18c0e5cc520d210476cc 100644 (file)
--- a/src/ap/acs.c
+++ b/src/ap/acs.c
@@ -472,7 +472,7 @@ static struct hostapd_channel_data *acs_find_chan(struct hostapd_iface *iface,
        for (i = 0; i < iface->current_mode->num_channels; i++) {
                chan = &iface->current_mode->channels[i];
 
-               if (!acs_usable_chan(chan))
+               if (chan->flag & HOSTAPD_CHAN_DISABLED)
                        continue;
 
                if (chan->freq == freq)
@@ -492,7 +492,8 @@ static struct hostapd_channel_data *acs_find_chan(struct hostapd_iface *iface,
 static struct hostapd_channel_data *
 acs_find_ideal_chan(struct hostapd_iface *iface)
 {
-       struct hostapd_channel_data *chan, *adj_chan, *ideal_chan = NULL;
+       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;
@@ -524,9 +525,10 @@ acs_find_ideal_chan(struct hostapd_iface *iface)
        for (i = 0; i < iface->current_mode->num_channels; i++) {
                chan = &iface->current_mode->channels[i];
 
-               if (!acs_usable_chan(chan))
+               if (chan->flag & HOSTAPD_CHAN_DISABLED)
                        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 &&
@@ -538,14 +540,17 @@ acs_find_ideal_chan(struct hostapd_iface *iface)
                        continue;
                }
 
-               factor = chan->interference_factor;
+               factor = 0;
+               if (acs_usable_chan(chan))
+                       factor = chan->interference_factor;
 
                for (j = 1; j < n_chans; j++) {
                        adj_chan = acs_find_chan(iface, chan->freq + (j * 20));
                        if (!adj_chan)
                                break;
 
-                       factor += adj_chan->interference_factor;
+                       if (acs_usable_chan(adj_chan))
+                               factor += adj_chan->interference_factor;
                }
 
                if (j != n_chans) {
@@ -564,22 +569,22 @@ acs_find_ideal_chan(struct hostapd_iface *iface)
 
                                adj_chan = acs_find_chan(iface, chan->freq +
                                                         (j * 20) - 5);
-                               if (adj_chan)
+                               if (adj_chan && acs_usable_chan(adj_chan))
                                        factor += adj_chan->interference_factor;
 
                                adj_chan = acs_find_chan(iface, chan->freq +
                                                         (j * 20) - 10);
-                               if (adj_chan)
+                               if (adj_chan && acs_usable_chan(adj_chan))
                                        factor += adj_chan->interference_factor;
 
                                adj_chan = acs_find_chan(iface, chan->freq +
                                                         (j * 20) + 5);
-                               if (adj_chan)
+                               if (adj_chan && acs_usable_chan(adj_chan))
                                        factor += adj_chan->interference_factor;
 
                                adj_chan = acs_find_chan(iface, chan->freq +
                                                         (j * 20) + 10);
-                               if (adj_chan)
+                               if (adj_chan && acs_usable_chan(adj_chan))
                                        factor += adj_chan->interference_factor;
                        }
                }
@@ -587,17 +592,24 @@ acs_find_ideal_chan(struct hostapd_iface *iface)
                wpa_printf(MSG_DEBUG, "ACS:  * channel %d: total interference = %Lg",
                           chan->chan, factor);
 
-               if (!ideal_chan || factor < ideal_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)
+       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 ideal_chan;
+       return rand_chan;
 }