AP MLD: Link-specific flushing of stations

Whenever a BSS was set up,hostapd flushed all stations via the flush()
driver operation which maps to NL80211_CMD_DEL_STATION in the nl80211
interface. However, in case of MLO, a station could have been connected
to other links by the time this link is coming up. Since link ID was not
passed to flush(), all those stations entries were also removed in the
driver which is wrong.

Include the link ID along with the command in AP MLD so that the driver
can use this link ID and flush only the stations that use the passed
link ID as one of their links.

Signed-off-by: Aditya Kumar Singh <quic_adisi@quicinc.com>

src/ap/ap_drv_ops.c

@@ -627,9 +627,17 @@ int hostapd_get_seqnum(const char *ifname, struct hostapd_data *hapd,
 
 int hostapd_flush(struct hostapd_data *hapd)
 {
+	int link_id = -1;
+
 	if (hapd->driver == NULL || hapd->driver->flush == NULL)
 		return 0;
-	return hapd->driver->flush(hapd->drv_priv);
+
+#ifdef CONFIG_IEEE80211BE
+	if (hapd->conf && hapd->conf->mld_ap)
+		link_id = hapd->mld_link_id;
+#endif /* CONFIG_IEEE80211BE */
+
+	return hapd->driver->flush(hapd->drv_priv, link_id);
 }
 
 

src/drivers/driver.h

@@ -3588,13 +3588,15 @@ struct wpa_driver_ops {
 	/**
 	 * flush - Flush all association stations (AP only)
 	 * @priv: Private driver interface data
+	 * @link_id: In case of MLO, valid link ID on which all associated
+	 *	stations will be flushed, -1 otherwise.
 	 * Returns: 0 on success, -1 on failure
 	 *
 	 * This function requests the driver to disassociate all associated
 	 * stations. This function does not need to be implemented if the
 	 * driver does not process association frames internally.
 	 */
-	int (*flush)(void *priv);
+	int (*flush)(void *priv, int link_id);
 
 	/**
 	 * set_generic_elem - Add IEs into Beacon/Probe Response frames (AP)

src/drivers/driver_atheros.c

@@ -632,7 +632,7 @@ atheros_get_seqnum(const char *ifname, void *priv, const u8 *addr, int idx,
 
 
 static int
-atheros_flush(void *priv)
+atheros_flush(void *priv, int link_id)
 {
 	u8 allsta[IEEE80211_ADDR_LEN];
 	os_memset(allsta, 0xff, IEEE80211_ADDR_LEN);

src/drivers/driver_bsd.c

@@ -946,7 +946,7 @@ bsd_get_seqnum(const char *ifname, void *priv, const u8 *addr, int idx,
 
 
 static int
-bsd_flush(void *priv)
+bsd_flush(void *priv, int link_id)
 {
 	u8 allsta[IEEE80211_ADDR_LEN];
 

src/drivers/driver_hostap.c

@@ -572,7 +572,7 @@ static int hostap_set_ssid(void *priv, const u8 *buf, int len)
 }
 
 
-static int hostap_flush(void *priv)
+static int hostap_flush(void *priv, int link_id)
 {
 	struct hostap_driver_data *drv = priv;
 	struct prism2_hostapd_param param;

src/drivers/driver_nl80211.c

@@ -7724,25 +7724,37 @@ static int i802_set_frag(void *priv, int frag)
 }
 
 
-static int i802_flush(void *priv)
+static int i802_flush(void *priv, int link_id)
 {
 	struct i802_bss *bss = priv;
 	struct nl_msg *msg;
 	int res;
 
-	wpa_printf(MSG_DEBUG, "nl80211: flush -> DEL_STATION %s (all)",
+	if (link_id == NL80211_DRV_LINK_ID_NA)
-		   bss->ifname);
+		wpa_printf(MSG_DEBUG, "nl80211: flush -> DEL_STATION %s (all)",
+			   bss->ifname);
+	else
+		wpa_printf(MSG_DEBUG,
+			   "nl80211: flush -> DEL_STATION %s (with link %d)",
+			   bss->ifname, link_id);
 
 	/*
 	 * XXX: FIX! this needs to flush all VLANs too
 	 */
 	msg = nl80211_bss_msg(bss, 0, NL80211_CMD_DEL_STATION);
+	if (link_id >= 0 && (bss->valid_links & BIT(link_id)) &&
+	    nla_put_u8(msg, NL80211_ATTR_MLO_LINK_ID, link_id))
+		goto fail;
+
 	res = send_and_recv_cmd(bss->drv, msg);
 	if (res) {
 		wpa_printf(MSG_DEBUG, "nl80211: Station flush failed: ret=%d "
 			   "(%s)", res, strerror(-res));
 	}
 	return res;
+fail:
+	nlmsg_free(msg);
+	return -1;
 }