DFS: Add capability to select radar-only channels

Introduce type parameter to dfs_get_valid_channel() routine to allow
selection of a radar-only channel where the CAC detection has not been
performed yet. This is a preliminary patch to enable background
radar/CAC detection.

Tested-by: Owen Peng <owen.peng@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

diff --git a/src/ap/dfs.c b/src/ap/dfs.c
index f9cfb7473dc41b7e5ac92048ef69c8bc64ff7dca..f2bc7eeb2fe83a52d5e765a556b7c4c7b8df288d 100644 (file)
--- a/src/ap/dfs.c
+++ b/src/ap/dfs.c
@@ -51,15 +51,33 @@ static int dfs_get_used_n_chans(struct hostapd_iface *iface, int *seg1)
 }
 
 
+enum dfs_channel_type {
+       DFS_ANY_CHANNEL,
+       DFS_AVAILABLE, /* non-radar or radar-available */
+       DFS_NO_CAC_YET, /* radar-not-yet-available */
+};
+
+/* dfs_channel_available: select new channel according to type parameter */
 static int dfs_channel_available(struct hostapd_channel_data *chan,
-                                int skip_radar)
+                                enum dfs_channel_type type)
 {
+       if (type == DFS_NO_CAC_YET) {
+               /* Select only radar channel where CAC has not been
+                * performed yet
+                */
+               if ((chan->flag & HOSTAPD_CHAN_RADAR) &&
+                   (chan->flag & HOSTAPD_CHAN_DFS_MASK) ==
+                    HOSTAPD_CHAN_DFS_USABLE)
+                       return 1;
+               return 0;
+       }
+
        /*
         * 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, unless they are available for immediate use.
         */
-       if (skip_radar && (chan->flag & HOSTAPD_CHAN_RADAR) &&
+       if (type == DFS_AVAILABLE && (chan->flag & HOSTAPD_CHAN_RADAR) &&
            ((chan->flag & HOSTAPD_CHAN_DFS_MASK) !=
             HOSTAPD_CHAN_DFS_AVAILABLE))
                return 0;
@@ -138,7 +156,7 @@ dfs_get_chan_data(struct hostapd_hw_modes *mode, int freq, int first_chan_idx)
 
 static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
                                    int first_chan_idx, int num_chans,
-                                   int skip_radar)
+                                   enum dfs_channel_type type)
 {
        struct hostapd_channel_data *first_chan, *chan;
        int i;
@@ -177,7 +195,7 @@ static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
                        return 0;
                }
 
-               if (!dfs_channel_available(chan, skip_radar)) {
+               if (!dfs_channel_available(chan, type)) {
                        wpa_printf(MSG_DEBUG, "DFS: channel not available %d",
                                   first_chan->freq + i * 20);
                        return 0;
@@ -207,7 +225,7 @@ static int is_in_chanlist(struct hostapd_iface *iface,
  */
 static int dfs_find_channel(struct hostapd_iface *iface,
                            struct hostapd_channel_data **ret_chan,
-                           int idx, int skip_radar)
+                           int idx, enum dfs_channel_type type)
 {
        struct hostapd_hw_modes *mode;
        struct hostapd_channel_data *chan;
@@ -232,7 +250,7 @@ static int dfs_find_channel(struct hostapd_iface *iface,
                }
 
                /* Skip incompatible chandefs */
-               if (!dfs_chan_range_available(mode, i, n_chans, skip_radar)) {
+               if (!dfs_chan_range_available(mode, i, n_chans, type)) {
                        wpa_printf(MSG_DEBUG,
                                   "DFS: range not available for %d (%d)",
                                   chan->freq, chan->chan);
@@ -475,7 +493,7 @@ dfs_get_valid_channel(struct hostapd_iface *iface,
                      int *secondary_channel,
                      u8 *oper_centr_freq_seg0_idx,
                      u8 *oper_centr_freq_seg1_idx,
-                     int skip_radar)
+                     enum dfs_channel_type type)
 {
        struct hostapd_hw_modes *mode;
        struct hostapd_channel_data *chan = NULL;
@@ -499,7 +517,7 @@ dfs_get_valid_channel(struct hostapd_iface *iface,
                return NULL;
 
        /* Get the count first */
-       num_available_chandefs = dfs_find_channel(iface, NULL, 0, skip_radar);
+       num_available_chandefs = dfs_find_channel(iface, NULL, 0, type);
        wpa_printf(MSG_DEBUG, "DFS: num_available_chandefs=%d",
                   num_available_chandefs);
        if (num_available_chandefs == 0)
@@ -508,7 +526,7 @@ dfs_get_valid_channel(struct hostapd_iface *iface,
        if (os_get_random((u8 *) &_rand, sizeof(_rand)) < 0)
                return NULL;
        chan_idx = _rand % num_available_chandefs;
-       dfs_find_channel(iface, &chan, chan_idx, skip_radar);
+       dfs_find_channel(iface, &chan, chan_idx, type);
        if (!chan) {
                wpa_printf(MSG_DEBUG, "DFS: no random channel found");
                return NULL;
@@ -537,7 +555,7 @@ dfs_get_valid_channel(struct hostapd_iface *iface,
                for (i = 0; i < num_available_chandefs - 1; i++) {
                        /* start from chan_idx + 1, end when chan_idx - 1 */
                        chan_idx2 = (chan_idx + 1 + i) % num_available_chandefs;
-                       dfs_find_channel(iface, &chan2, chan_idx2, skip_radar);
+                       dfs_find_channel(iface, &chan2, chan_idx2, type);
                        if (chan2 && abs(chan2->chan - chan->chan) > 12) {
                                /* two channels are not adjacent */
                                sec_chan_idx_80p80 = chan2->chan;
@@ -575,7 +593,8 @@ static int dfs_set_valid_channel(struct hostapd_iface *iface, int skip_radar)
        int sec = 0;
 
        channel = dfs_get_valid_channel(iface, &sec, &cf1, &cf2,
-                                       skip_radar);
+                                       skip_radar ? DFS_AVAILABLE :
+                                       DFS_ANY_CHANNEL);
        if (!channel) {
                wpa_printf(MSG_ERROR, "could not get valid channel");
                return -1;
@@ -958,7 +977,8 @@ dfs_downgrade_bandwidth(struct hostapd_iface *iface, int *secondary_channel,
                channel = dfs_get_valid_channel(iface, secondary_channel,
                                                oper_centr_freq_seg0_idx,
                                                oper_centr_freq_seg1_idx,
-                                               *skip_radar);
+                                               *skip_radar ? DFS_AVAILABLE :
+                                               DFS_ANY_CHANNEL);
                if (channel) {
                        wpa_printf(MSG_DEBUG, "DFS: Selected channel: %d",
                                   channel->chan);
@@ -999,7 +1019,8 @@ static int hostapd_dfs_start_channel_switch_cac(struct hostapd_iface *iface)
        channel = dfs_get_valid_channel(iface, &secondary_channel,
                                        &oper_centr_freq_seg0_idx,
                                        &oper_centr_freq_seg1_idx,
-                                       skip_radar);
+                                       skip_radar ? DFS_AVAILABLE :
+                                       DFS_ANY_CHANNEL);
 
        if (!channel) {
                channel = dfs_downgrade_bandwidth(iface, &secondary_channel,
@@ -1070,7 +1091,8 @@ static int hostapd_dfs_start_channel_switch(struct hostapd_iface *iface)
        channel = dfs_get_valid_channel(iface, &secondary_channel,
                                        &oper_centr_freq_seg0_idx,
                                        &oper_centr_freq_seg1_idx,
-                                       skip_radar);
+                                       skip_radar ? DFS_AVAILABLE :
+                                       DFS_ANY_CHANNEL);
 
        if (!channel) {
                /*