hostapd: Add config option chanlist for DFS channels

Different channels allow different transmission power, at least in ETSI
countries. Also, ETSI requires a "channel plan" for DFS operation, and
channels should be randomly choosen from these channels.

Add a channel list configuration option for users to add channels
hostapd may pick from.

Signed-hostap: Simon Wunderlich <sw@simonwunderlich.de>

diff --git a/hostapd/config_file.c b/hostapd/config_file.c
index b7d1f2f..b6f1d1b 100644 (file)
--- a/hostapd/config_file.c
+++ b/hostapd/config_file.c
@@ -2486,6 +2486,13 @@ static int hostapd_config_fill(struct hostapd_config *conf,
                                conf->channel = 0;
                        } else
                                conf->channel = atoi(pos);
+               } else if (os_strcmp(buf, "chanlist") == 0) {
+                       if (hostapd_parse_intlist(&conf->chanlist, pos)) {
+                               wpa_printf(MSG_ERROR,
+                                          "Line %d: invalid channel list",
+                                          line);
+                               errors++;
+                       }
                } else if (os_strcmp(buf, "beacon_int") == 0) {
                        int val = atoi(pos);
                        /* MIB defines range as 1..65535, but very small values

diff --git a/hostapd/hostapd.conf b/hostapd/hostapd.conf
index c745fe8..7ea186e 100644 (file)
--- a/hostapd/hostapd.conf
+++ b/hostapd/hostapd.conf
@@ -154,6 +154,14 @@ channel=1
 # Defaults:
 #acs_num_scans=5
 
+# Channel list restriction. This option allows hostapd to select one of the
+# provided channels when a channel should be automatically selected. This
+# is currently only used for DFS when the current channels becomes unavailable
+# due to radar interference, and is currently only useful when ieee80211h=1 is
+# set.
+# Default: not set (allow any enabled channel to be selected)
+#chanlist=100 104 108 112 116
+
 # Beacon interval in kus (1.024 ms) (default: 100; range 15..65535)
 beacon_int=100
 

diff --git a/src/ap/ap_config.c b/src/ap/ap_config.c
index 5252cba..3ca85a0 100644 (file)
--- a/src/ap/ap_config.c
+++ b/src/ap/ap_config.c
@@ -562,6 +562,7 @@ void hostapd_config_free(struct hostapd_config *conf)
        os_free(conf->bss);
        os_free(conf->supported_rates);
        os_free(conf->basic_rates);
+       os_free(conf->chanlist);
 
        os_free(conf);
 }

diff --git a/src/ap/ap_config.h b/src/ap/ap_config.h
index 638a21c..aa3a51a 100644 (file)
--- a/src/ap/ap_config.h
+++ b/src/ap/ap_config.h
@@ -525,6 +525,7 @@ struct hostapd_config {
        int fragm_threshold;
        u8 send_probe_response;
        u8 channel;
+       int *chanlist;
        enum hostapd_hw_mode hw_mode; /* HOSTAPD_MODE_IEEE80211A, .. */
        enum {
                LONG_PREAMBLE = 0,

diff --git a/src/ap/dfs.c b/src/ap/dfs.c
index 92eda21..590a03a 100644 (file)
--- a/src/ap/dfs.c
+++ b/src/ap/dfs.c
@@ -139,6 +139,22 @@ static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
 }
 
 
+static int is_in_chanlist(struct hostapd_iface *iface,
+                         struct hostapd_channel_data *chan)
+{
+       int *entry;
+
+       if (!iface->conf->chanlist)
+               return 1;
+
+       for (entry = iface->conf->chanlist; *entry != -1; entry++) {
+               if (*entry == chan->chan)
+                       return 1;
+       }
+       return 0;
+}
+
+
 /*
  * The function assumes HT40+ operation.
  * Make sure to adjust the following variables after calling this:
@@ -171,6 +187,9 @@ static int dfs_find_channel(struct hostapd_iface *iface,
                if (!dfs_chan_range_available(mode, i, n_chans, skip_radar))
                        continue;
 
+               if (!is_in_chanlist(iface, chan))
+                       continue;
+
                if (ret_chan && idx == channel_idx) {
                        wpa_printf(MSG_DEBUG, "Selected ch. #%d", chan->chan);
                        *ret_chan = chan;