hostapd: provide BSS-transition-queries to ubus subscribers

Provide incoming BSS transition queries to ubus subscribers.

This allows external steering daemons to provide clients with
an optimal list of transition candidates.

This commit has no functional state in case no ubus subscriber is
present or it does not handle this ubus message.

To prevent hostapd from sending out a generic response by itself, a
subscribing daemon has to return a non-zero response code to hostapd.

Signed-off-by: David Bauer <[email protected]>

package/network/services/hostapd/patches/600-ubus_support.patch

@@ -515,7 +515,17 @@
 
 --- a/src/ap/wnm_ap.c
 +++ b/src/ap/wnm_ap.c
-@@ -463,7 +463,7 @@ static void ieee802_11_rx_bss_trans_mgmt
+@@ -441,7 +441,8 @@ static void ieee802_11_rx_bss_trans_mgmt
+ 	wpa_hexdump(MSG_DEBUG, "WNM: BSS Transition Candidate List Entries",
+ 		    pos, end - pos);
+
+-	ieee802_11_send_bss_trans_mgmt_request(hapd, addr, dialog_token);
++	if (!hostapd_ubus_notify_bss_transition_query(hapd, addr, dialog_token, reason, pos, end - pos))
++		ieee802_11_send_bss_trans_mgmt_request(hapd, addr, dialog_token);
+ }
+
+
+@@ -463,7 +464,7 @@ static void ieee802_11_rx_bss_trans_mgmt
  					      size_t len)
  {
  	u8 dialog_token, status_code, bss_termination_delay;
@@ -524,15 +534,15 @@
  	int enabled = hapd->conf->bss_transition;
  	struct sta_info *sta;
 
-@@ -510,6 +510,7 @@ static void ieee802_11_rx_bss_trans_mgmt
+@@ -510,6 +511,7 @@ static void ieee802_11_rx_bss_trans_mgmt
  			wpa_printf(MSG_DEBUG, "WNM: not enough room for Target BSSID field");
  			return;
  		}
 +		target_bssid = pos;
  		sta->agreed_to_steer = 1;
  		eloop_cancel_timeout(ap_sta_reset_steer_flag_timer, hapd, sta);
  		eloop_register_timeout(2, 0, ap_sta_reset_steer_flag_timer,
-@@ -529,6 +530,10 @@ static void ieee802_11_rx_bss_trans_mgmt
+@@ -529,6 +531,10 @@ static void ieee802_11_rx_bss_trans_mgmt
  			MAC2STR(addr), status_code, bss_termination_delay);
  	}
 

package/network/services/hostapd/src/src/ap/ubus.c

@@ -1850,13 +1850,30 @@ void hostapd_ubus_notify_radar_detected(struct hostapd_iface *iface, int frequen
 	}
 }
 
+#ifdef CONFIG_WNM_AP
+static void hostapd_ubus_notify_bss_transition_add_candidate_list(
+	const u8 *candidate_list, u16 candidate_list_len)
+{
+	char *cl_str;
+	int i;
+
+	if (candidate_list_len == 0)
+		return;
+
+	cl_str = blobmsg_alloc_string_buffer(&b, "candidate-list", candidate_list_len * 2 + 1);
+	for (i = 0; i < candidate_list_len; i++)
+		snprintf(&cl_str[i*2], 3, "%02X", candidate_list[i]);
+	blobmsg_add_string_buffer(&b);
+
+}
+#endif
+
 void hostapd_ubus_notify_bss_transition_response(
 	struct hostapd_data *hapd, const u8 *addr, u8 dialog_token, u8 status_code,
 	u8 bss_termination_delay, const u8 *target_bssid,
 	const u8 *candidate_list, u16 candidate_list_len)
 {
 #ifdef CONFIG_WNM_AP
-	char *cl_str;
 	u16 i;
 
 	if (!hapd->ubus.obj.has_subscribers)
@@ -1872,13 +1889,45 @@ void hostapd_ubus_notify_bss_transition_response(
 	blobmsg_add_u8(&b, "bss-termination-delay", bss_termination_delay);
 	if (target_bssid)
 		blobmsg_add_macaddr(&b, "target-bssid", target_bssid);
-	if (candidate_list_len > 0) {
-		cl_str = blobmsg_alloc_string_buffer(&b, "candidate-list", candidate_list_len * 2 + 1);
-		for (i = 0; i < candidate_list_len; i++)
-			snprintf(&cl_str[i*2], 3, "%02X", candidate_list[i]);
-		blobmsg_add_string_buffer(&b);
-	}
+
+	hostapd_ubus_notify_bss_transition_add_candidate_list(candidate_list, candidate_list_len);
 
 	ubus_notify(ctx, &hapd->ubus.obj, "bss-transition-response", b.head, -1);
 #endif
 }
+
+int hostapd_ubus_notify_bss_transition_query(
+	struct hostapd_data *hapd, const u8 *addr, u8 dialog_token, u8 reason,
+	const u8 *candidate_list, u16 candidate_list_len)
+{
+#ifdef CONFIG_WNM_AP
+	struct ubus_event_req ureq = {};
+	char *cl_str;
+	u16 i;
+
+	if (!hapd->ubus.obj.has_subscribers)
+		return 0;
+
+	if (!addr)
+		return 0;
+
+	blob_buf_init(&b, 0);
+	blobmsg_add_macaddr(&b, "address", addr);
+	blobmsg_add_u8(&b, "dialog-token", dialog_token);
+	blobmsg_add_u8(&b, "reason", reason);
+	hostapd_ubus_notify_bss_transition_add_candidate_list(candidate_list, candidate_list_len);
+
+	if (!hapd->ubus.notify_response) {
+		ubus_notify(ctx, &hapd->ubus.obj, "bss-transition-query", b.head, -1);
+		return 0;
+	}
+
+	if (ubus_notify_async(ctx, &hapd->ubus.obj, "bss-transition-query", b.head, &ureq.nreq))
+		return 0;
+
+	ureq.nreq.status_cb = ubus_event_cb;
+	ubus_complete_request(ctx, &ureq.nreq.req, 100);
+
+	return ureq.resp;
+#endif
+}