[PATCH 4/4] DFS: add supported channel BW checking

[Dmitrii Lebed]

From: Dmitry Lebed <dlebed at quantenna.com>

While selecting new channel as a reation to radar event
we need to take into account supported BW for each channel
provided via nl80211.
Without this modification hostapd can select unsupported
channel, will fail to use it and eventually will halt.

Signed-off-by: Dmitry Lebed <dlebed at quantenna.com>
---
 src/ap/dfs.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/ap/dfs.c b/src/ap/dfs.c
index 8c56cbb96..f2c115ca5 100644
--- a/src/ap/dfs.c
+++ b/src/ap/dfs.c
@@ -143,18 +143,30 @@ static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
 {
        struct hostapd_channel_data *first_chan, *chan;
        int i;
+       const u32 bw = num_chan_to_bw(num_chans);

        if (first_chan_idx + num_chans > mode->num_channels)
                return 0;

        first_chan = &mode->channels[first_chan_idx];

+       /* hostapd DFS implementation assumes first channel as primary,
+        * if it's not allowed to use fist channel as primary
+        * then decline the whole channel range */
+       if (!chan_pri_allowed(first_chan))
+               return 0;
+
        for (i = 0; i < num_chans; i++) {
                chan = dfs_get_chan_data(mode, first_chan->freq + i * 20,
                                         first_chan_idx);
                if (!chan)
                        return 0;

+               /* HT 40MHz secondary channel availability checked only for
+                * primary channel */
+               if (!chan_bw_allowed(chan, bw, 1, !i))
+                       return 0;
+
                if (!dfs_channel_available(chan, skip_radar))
                        return 0;
        }
@@ -195,9 +207,9 @@ static int dfs_find_channel(struct hostapd_iface *iface,
                chan = &mode->channels[i];

                /* Skip HT40/VHT incompatible channels */
-               if (iface->conf->ieee80211n &&
-                   iface->conf->secondary_channel &&
-                   !dfs_is_chan_allowed(chan, n_chans))
+               if (iface->conf->ieee80211n && iface->conf->secondary_channel &&
+                   (!dfs_is_chan_allowed(chan, n_chans) ||
+                    !(chan->allowed_bw & HOSTAPD_CHAN_WIDTH_40P)))
                        continue;

                /* Skip incompatible chandefs */
--
2.16.1



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