WNM: Configurable BSS Max Idle Period management on AP

Allow AP's behavior for BSS Max Idle Period management to be configured.
Previously, this was automatically enabled for all CONFIG_WNM_AP=y
builds. This can now be changed with the new hostapd configuration
parameter bss_max_idle:
0 = BSS Max Idle Period management disabled
1 = BSS Max Idle Period management enabled
    (default and the previous behavior)
2 = BSS Max Idle Period management enabled with requirement for
    protected keep-alive frames

Signed-off-by: Jouni Malinen <quic_jouni@quicinc.com>

hostapd/config_file.c

@@ -2549,6 +2549,15 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 		bss->ap_max_inactivity = atoi(pos);
 	} else if (os_strcmp(buf, "skip_inactivity_poll") == 0) {
 		bss->skip_inactivity_poll = atoi(pos);
+	} else if (os_strcmp(buf, "bss_max_idle") == 0) {
+		int val = atoi(pos);
+
+		if (val < 0 || val > 2) {
+			wpa_printf(MSG_ERROR,
+				   "Line %d: Invalid bss_max_idle value", line);
+			return 1;
+		}
+		bss->bss_max_idle = val;
 	} else if (os_strcmp(buf, "config_id") == 0) {
 		os_free(bss->config_id);
 		bss->config_id = os_strdup(pos);

hostapd/hostapd.conf

@@ -522,6 +522,13 @@ wmm_ac_vo_acm=0
 # even if they are still in range of the AP. This can be done by setting
 # skip_inactivity_poll to 1 (default 0).
 #skip_inactivity_poll=0
+#
+# BSS max idle period management
+# 0 = disabled (do not advertise and manage BSS max idle period)
+# 1 = enabled (advertise and manage BSS max idle period; default)
+# 2 = enabled requiring protected frames (advertise and manage BSS max idle
+#     period and require STAs to use protected keep-alive frames)
+#bss_max_idle=1
 
 # Disassociate stations based on excessive transmission failures or other
 # indications of connection loss. This depends on the driver capabilities and

src/ap/ap_config.c

@@ -92,6 +92,7 @@ void hostapd_config_defaults_bss(struct hostapd_bss_config *bss)
 	bss->eap_sim_id = 3;
 	bss->eap_sim_aka_fast_reauth_limit = 1000;
 	bss->ap_max_inactivity = AP_MAX_INACTIVITY;
+	bss->bss_max_idle = 1;
 	bss->eapol_version = EAPOL_VERSION;
 
 	bss->max_listen_interval = 65535;

src/ap/ap_config.h

@@ -465,6 +465,7 @@ struct hostapd_bss_config {
 				 */
 
 	int ap_max_inactivity;
+	int bss_max_idle;
 	int ignore_broadcast_ssid;
 	int no_probe_resp_if_max_sta;
 

src/ap/ieee802_11_shared.c

@@ -742,7 +742,8 @@ u8 * hostapd_eid_bss_max_idle_period(struct hostapd_data *hapd, u8 *eid)
 	u8 *pos = eid;
 
 #ifdef CONFIG_WNM_AP
-	if (hapd->conf->ap_max_inactivity > 0) {
+	if (hapd->conf->ap_max_inactivity > 0 &&
+	    hapd->conf->bss_max_idle) {
 		unsigned int val;
 		*pos++ = WLAN_EID_BSS_MAX_IDLE_PERIOD;
 		*pos++ = 3;
@@ -757,7 +758,9 @@ u8 * hostapd_eid_bss_max_idle_period(struct hostapd_data *hapd, u8 *eid)
 			val = 65535;
 		WPA_PUT_LE16(pos, val);
 		pos += 2;
-		*pos++ = 0x00; /* TODO: Protected Keep-Alive Required */
+		/* Set the Protected Keep-Alive Required bit based on
+		 * configuration */
+		*pos++ = hapd->conf->bss_max_idle == 2 ? BIT(0) : 0x00;
 	}
 #endif /* CONFIG_WNM_AP */