hostapd: add support for specifying the maxassoc parameter as a devic…

…e option

It allows enforcing a limit on associated stations to be enforced for the
full device, e.g. in order to deal with hardware/driver limitations

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/network/services/hostapd/files/hostapd.sh

@@ -103,6 +103,7 @@ hostapd_common_add_device_config() {
 	config_add_int rts_threshold
 	config_add_int rssi_reject_assoc_rssi
 	config_add_int rssi_ignore_probe_request
+	config_add_int maxassoc
 
 	config_add_string acs_chan_bias
 	config_add_array hostapd_options
@@ -120,7 +121,7 @@ hostapd_prepare_device_config() {
 
 	json_get_vars country country_ie beacon_int:100 dtim_period:2 doth require_mode legacy_rates \
 		acs_chan_bias local_pwr_constraint spectrum_mgmt_required airtime_mode cell_density \
-		rts_threshold beacon_rate rssi_reject_assoc_rssi rssi_ignore_probe_request
+		rts_threshold beacon_rate rssi_reject_assoc_rssi rssi_ignore_probe_request maxassoc
 
 	hostapd_set_log_options base_cfg
 
@@ -220,6 +221,7 @@ hostapd_prepare_device_config() {
 	[ -n "$rts_threshold" ] && append base_cfg "rts_threshold=$rts_threshold" "$N"
 	append base_cfg "dtim_period=$dtim_period" "$N"
 	[ "$airtime_mode" -gt 0 ] && append base_cfg "airtime_mode=$airtime_mode" "$N"
+	[ -n "$maxassoc" ] && append base_cfg "iface_max_num_sta=$maxassoc" "$N"
 
 	json_get_values opts hostapd_options
 	for val in $opts; do

package/network/services/hostapd/patches/720-iface_max_num_sta.patch

@@ -0,0 +1,82 @@
+--- a/hostapd/config_file.c
++++ b/hostapd/config_file.c
+@@ -2873,6 +2873,14 @@ static int hostapd_config_fill(struct ho
+ 				   line, bss->max_num_sta, MAX_STA_COUNT);
+ 			return 1;
+ 		}
++	} else if (os_strcmp(buf, "iface_max_num_sta") == 0) {
++		conf->max_num_sta = atoi(pos);
++		if (conf->max_num_sta < 0 ||
++		    conf->max_num_sta > MAX_STA_COUNT) {
++			wpa_printf(MSG_ERROR, "Line %d: Invalid max_num_sta=%d; allowed range 0..%d",
++				   line, conf->max_num_sta, MAX_STA_COUNT);
++			return 1;
++		}
+ 	} else if (os_strcmp(buf, "wpa") == 0) {
+ 		bss->wpa = atoi(pos);
+ 	} else if (os_strcmp(buf, "extended_key_id") == 0) {
+--- a/src/ap/hostapd.h
++++ b/src/ap/hostapd.h
+@@ -648,6 +648,7 @@ void hostapd_cleanup_cs_params(struct ho
+ void hostapd_periodic_iface(struct hostapd_iface *iface);
+ int hostapd_owe_trans_get_info(struct hostapd_data *hapd);
+ void hostapd_ocv_check_csa_sa_query(void *eloop_ctx, void *timeout_ctx);
++int hostapd_check_max_sta(struct hostapd_data *hapd);
+
+ /* utils.c */
+ int hostapd_register_probereq_cb(struct hostapd_data *hapd,
+--- a/src/ap/hostapd.c
++++ b/src/ap/hostapd.c
+@@ -236,6 +236,30 @@ static int hostapd_iface_conf_changed(st
+ }
+
+
++static inline int hostapd_iface_num_sta(struct hostapd_iface *iface)
++{
++	int num_sta = 0;
++	int i;
++
++	for (i = 0; i < iface->num_bss; i++)
++		num_sta += iface->bss[i]->num_sta;
++
++	return num_sta;
++}
++
++
++int hostapd_check_max_sta(struct hostapd_data *hapd)
++{
++	if (hapd->num_sta >= hapd->conf->max_num_sta)
++		return 1;
++
++	if (hapd->iconf->max_num_sta &&
++	    hostapd_iface_num_sta(hapd->iface) >= hapd->iconf->max_num_sta)
++		return 1;
++
++	return 0;
++}
++
+ int hostapd_reload_config(struct hostapd_iface *iface, int reconf)
+ {
+ 	struct hapd_interfaces *interfaces = iface->interfaces;
+--- a/src/ap/beacon.c
++++ b/src/ap/beacon.c
+@@ -1039,7 +1039,7 @@ void handle_probe_req(struct hostapd_dat
+ 	if (hapd->conf->no_probe_resp_if_max_sta &&
+ 	    is_multicast_ether_addr(mgmt->da) &&
+ 	    is_multicast_ether_addr(mgmt->bssid) &&
+-	    hapd->num_sta >= hapd->conf->max_num_sta &&
++	    hostapd_check_max_sta(hapd) &&
+ 	    !ap_get_sta(hapd, mgmt->sa)) {
+ 		wpa_printf(MSG_MSGDUMP, "%s: Ignore Probe Request from " MACSTR
+ 			   " since no room for additional STA",
+--- a/src/ap/ap_config.h
++++ b/src/ap/ap_config.h
+@@ -976,6 +976,8 @@ struct hostapd_config {
+ 	unsigned int track_sta_max_num;
+ 	unsigned int track_sta_max_age;
+
++	int max_num_sta;
++
+ 	char country[3]; /* first two octets: country code as described in
+ 			  * ISO/IEC 3166-1. Third octet:
+ 			  * ' ' (ascii 32): all environments