[PATCH 2/2] hostapd: Configure spectrum management capability

Marek Puzyniak marek.puzyniak at tieto.com
Fri Feb 21 08:42:18 EST 2014


From: Chaitanya T K <chaitanyatk at posedge.com>

Add configuration of Spectrum Managment subfield in
the Capability Information of Beacon, Probe Response and
Association Response. Spectrum Management bit is set when directly
requested by new configuration option spectrum_mgmt_required=1
or when AP is running on DFS channels. In future also TPC
shall require this bit to be set.

Signed-hostap: Srinivasan <srinivasanb at posedge.com>
Signed-hostap: Chaitanya T K <chaitanyatk at posedge.com>
Signed-hostap: Marek Puzyniak <marek.puzyniak at tieto.com>
---
 hostapd/config_file.c |  2 ++
 hostapd/hostapd.conf  |  7 +++++++
 src/ap/ap_config.c    |  6 ++++++
 src/ap/ap_config.h    |  3 +++
 src/ap/beacon.c       | 43 +++++++++++++++++++++++++++++++++++++++----
 src/ap/dfs.c          | 19 +++++++++++++++++++
 src/ap/dfs.h          |  2 ++
 src/ap/ieee802_11.c   | 21 +++++++++++++++++++++
 8 files changed, 99 insertions(+), 4 deletions(-)

diff --git a/hostapd/config_file.c b/hostapd/config_file.c
index ef4958a..cde78f1 100644
--- a/hostapd/config_file.c
+++ b/hostapd/config_file.c
@@ -2916,6 +2916,8 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 				errors++;
 			} else
 				conf->local_pwr_constraint = val;
+		} else if (os_strcmp(buf, "spectrum_mgmt_required") == 0) {
+			conf->spectrum_mgmt_required = atoi(pos);
 		} else {
 			wpa_printf(MSG_ERROR, "Line %d: unknown configuration "
 				   "item '%s'", line, buf);
diff --git a/hostapd/hostapd.conf b/hostapd/hostapd.conf
index 15cd364..5ae1ab9 100644
--- a/hostapd/hostapd.conf
+++ b/hostapd/hostapd.conf
@@ -116,6 +116,13 @@ ssid=test
 # Valid values are 0..255.
 #local_pwr_constraint=3
 
+# Set Spectrum Managment subfield in the Capability Information field.
+# This config option forces Spectrum Management bit to be set. When this
+# option is not set then value of Spectrum Management bit depends on whether
+# DFS or TPC is reuired by regulatory authorities.This can be used only with
+# ieee80211d=1 and local_pwr_constraint configured.
+#spectrum_mgmt_required=1
+
 # Operation mode (a = IEEE 802.11a, b = IEEE 802.11b, g = IEEE 802.11g,
 # ad = IEEE 802.11ad (60 GHz); a/g options are used with IEEE 802.11n, too, to
 # specify band)
diff --git a/src/ap/ap_config.c b/src/ap/ap_config.c
index 6c80e48..cc64f92 100644
--- a/src/ap/ap_config.c
+++ b/src/ap/ap_config.c
@@ -838,6 +838,12 @@ int hostapd_config_check(struct hostapd_config *conf, int full_config)
 		return -1;
 	}
 
+	if (full_config && conf->spectrum_mgmt_required &&
+	    conf->local_pwr_constraint == -1) {
+		wpa_printf(MSG_ERROR, "Cannot set Spectrum Management bit "
+			   "without Country and Power Constraint elements");
+		return -1;
+	}
 	for (i = 0; i < conf->num_bss; i++) {
 		if (hostapd_config_check_bss(conf->bss[i], conf, full_config))
 			return -1;
diff --git a/src/ap/ap_config.h b/src/ap/ap_config.h
index c641a83..c8ba441 100644
--- a/src/ap/ap_config.h
+++ b/src/ap/ap_config.h
@@ -526,6 +526,9 @@ struct hostapd_config {
 	 */
 	int local_pwr_constraint;
 
+	/* Control Spectrum Management bit */
+	int spectrum_mgmt_required;
+
 	struct hostapd_tx_queue_params tx_queue[NUM_TX_QUEUES];
 
 	/*
diff --git a/src/ap/beacon.c b/src/ap/beacon.c
index 36b0074..5da68f1 100644
--- a/src/ap/beacon.c
+++ b/src/ap/beacon.c
@@ -27,6 +27,7 @@
 #include "ap_drv_ops.h"
 #include "beacon.h"
 #include "hs20.h"
+#include "dfs.h"
 
 
 #ifdef NEED_AP_MLME
@@ -105,13 +106,44 @@ static u8 * hostapd_eid_erp_info(struct hostapd_data *hapd, u8 *eid)
 static u8 * hostapd_eid_pwr_constraint(struct hostapd_data *hapd, u8 *eid)
 {
 	u8 *pos = eid;
+	int local_pwr_constraint = 0;
+	int dfs;
 
-	if (hapd->iconf->local_pwr_constraint == -1 ||
-	    hapd->iface->current_mode == NULL ||
-	    hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211A)
+	if (hapd->iface->current_mode == NULL ||
+            hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211A)
+                return eid;
+
+	/*
+	 * There is no DFS support and power constraint was not direcly
+	 * requested by config option.
+	 */
+	if (!hapd->iconf->ieee80211h &&
+	    hapd->iconf->local_pwr_constraint == -1)
+		return eid;
+
+	/* Check if DFS is required by regulatory. */
+	dfs = hostapd_is_dfs_required(hapd->iface);
+	if (dfs < 0 ) {
+		wpa_printf(MSG_WARNING, "Failed to check if dfs "
+			   "is required ret=%d", dfs);
+		dfs = 0;
+	}
+
+	if (dfs == 0 && hapd->iconf->local_pwr_constraint == -1)
 		return eid;
 
 	/*
+	 * ieee80211h (DFS) is enabled so Power Constraint element shall
+	 * be added when running on DFS channel whenever local_pwr_constraint
+	 * is configured or not. In order to meet regulations when TPC is not
+	 * implemented using a transmit power that is below the legal maximum
+	 * (including any mitigation factor) should help. In this case 3dB below
+	 * maximum allowed transmit power.
+	 */
+	if (hapd->iconf->local_pwr_constraint == -1)
+		local_pwr_constraint = 3;
+
+	/*
 	 * A STA that is not an AP shall use a transmit power less than or
 	 * equal to the local maximum transmit power level for the channel.
 	 * The local maximum transmit power can be calculated from the formula:
@@ -126,7 +158,10 @@ static u8 * hostapd_eid_pwr_constraint(struct hostapd_data *hapd, u8 *eid)
 	/* Length */
 	*pos++ = 1;
 	/* Local Power Constraint */
-	*pos++ = hapd->iconf->local_pwr_constraint;
+	if (local_pwr_constraint)
+		*pos++ = local_pwr_constraint;
+	else
+		*pos++ = hapd->iconf->local_pwr_constraint;
 
 	return pos;
 }
diff --git a/src/ap/dfs.c b/src/ap/dfs.c
index ec691db..cd8742e 100644
--- a/src/ap/dfs.c
+++ b/src/ap/dfs.c
@@ -801,3 +801,22 @@ int hostapd_dfs_nop_finished(struct hostapd_iface *iface, int freq,
 		      cf1, cf2, HOSTAPD_CHAN_DFS_USABLE);
 	return 0;
 }
+
+int hostapd_is_dfs_required(struct hostapd_iface *iface)
+{
+	int n_chans, start_chan_idx;
+	int res = 0;
+
+	/* Get start (first) channel for current configuration */
+	start_chan_idx = dfs_get_start_chan_idx(iface);
+	if (start_chan_idx == -1)
+		return -1;
+
+	/* Get number of used channels, depend on width */
+	n_chans = dfs_get_used_n_chans(iface);
+
+	/* Check if any of configured channels require DFS */
+	res = dfs_check_chans_radar(iface, start_chan_idx, n_chans);
+
+	return res;
+}
diff --git a/src/ap/dfs.h b/src/ap/dfs.h
index 859ff79..2710021 100644
--- a/src/ap/dfs.h
+++ b/src/ap/dfs.h
@@ -21,5 +21,7 @@ int hostapd_dfs_radar_detected(struct hostapd_iface *iface, int freq,
 int hostapd_dfs_nop_finished(struct hostapd_iface *iface, int freq,
 			     int ht_enabled,
 			     int chan_offset, int chan_width, int cf1, int cf2);
+int hostapd_is_dfs_required(struct hostapd_iface *iface);
+
 
 #endif /* DFS_H */
diff --git a/src/ap/ieee802_11.c b/src/ap/ieee802_11.c
index 9251ac3..342ef8d 100644
--- a/src/ap/ieee802_11.c
+++ b/src/ap/ieee802_11.c
@@ -38,6 +38,7 @@
 #include "ap_drv_ops.h"
 #include "wnm_ap.h"
 #include "ieee802_11.h"
+#include "dfs.h"
 
 
 u8 * hostapd_eid_supp_rates(struct hostapd_data *hapd, u8 *eid)
@@ -137,6 +138,15 @@ u16 hostapd_own_capab_info(struct hostapd_data *hapd, struct sta_info *sta,
 {
 	int capab = WLAN_CAPABILITY_ESS;
 	int privacy;
+	int dfs;
+
+	/* Check if any of configured channels require DFS */
+	dfs = hostapd_is_dfs_required(hapd->iface);
+	if (dfs < 0 ) {
+		wpa_printf(MSG_WARNING, "Failed to check if dfs "
+			   "is required ret=%d", dfs);
+		dfs = 0;
+	}
 
 	if (hapd->iface->num_sta_no_short_preamble == 0 &&
 	    hapd->iconf->preamble == SHORT_PREAMBLE)
@@ -174,6 +184,17 @@ u16 hostapd_own_capab_info(struct hostapd_data *hapd, struct sta_info *sta,
 	    hapd->iface->num_sta_no_short_slot_time == 0)
 		capab |= WLAN_CAPABILITY_SHORT_SLOT_TIME;
 
+	/*
+	 * Currently Spectrum Management capability bit is set when directly
+	 * requested in configuration by spectrum_mgmt_required or when AP is
+	 * running on DFS channel.
+	 * TODO: Also consider driver support for TPC to set Spectrum Mgmt bit
+	 */
+	if (hapd->iface->current_mode &&
+	    hapd->iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A &&
+	    (hapd->iconf->spectrum_mgmt_required || dfs))
+		capab |= WLAN_CAPABILITY_SPECTRUM_MGMT;
+
 	return capab;
 }
 
-- 
1.8.1.2



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