Bluetooth: adv: add USE_NRPA advertising option

Allows the application to force the use of an NRPA.

This is applied regardless of any other roles running (ie scanner) or
advertising type.

Signed-off-by: Jonathan Rico <[email protected]>
Co-authored-by: Aleksander Wasaznik <[email protected]>

Author: 2 people

include/zephyr/bluetooth/bluetooth.h

@@ -685,6 +685,20 @@ enum {
 	 * @note Requires @ref BT_LE_ADV_OPT_USE_NAME
 	 */
 	BT_LE_ADV_OPT_FORCE_NAME_IN_AD = BIT(18),
+
+	/**
+	 * @brief Advertise using a Non-Resolvable Private Address.
+	 *
+	 * A new NRPA is set when updating the advertising parameters.
+	 *
+	 * This is an advanced feature; most users will want to enable
+	 * @kconfig{CONFIG_BT_EXT_ADV} instead.
+	 *
+	 * @note Not implemented when @kconfig{CONFIG_BT_PRIVACY}.
+	 *
+	 * @note Mutually exclusive with BT_LE_ADV_OPT_USE_IDENTITY.
+	 */
+	BT_LE_ADV_OPT_USE_NRPA = BIT(19),
 };
 
 /** LE Advertising Parameters. */

subsys/bluetooth/host/adv.c

@@ -1130,6 +1130,8 @@ static int le_ext_adv_param_set(struct bt_le_ext_adv *adv,
 	cp = net_buf_add(buf, sizeof(*cp));
 	(void)memset(cp, 0, sizeof(*cp));
 
+	adv->options = param->options;
+
 	err = bt_id_set_adv_own_addr(adv, param->options, dir_adv,
 				     &cp->own_addr_type);
 	if (err) {
@@ -1151,8 +1153,6 @@ static int le_ext_adv_param_set(struct bt_le_ext_adv *adv,
 	cp->filter_policy = get_filter_policy(param->options);
 	cp->tx_power = BT_HCI_LE_ADV_TX_POWER_NO_PREF;
 
-	adv->options = param->options;
-
 	cp->prim_adv_phy = BT_HCI_LE_PHY_1M;
 	if ((param->options & BT_LE_ADV_OPT_EXT_ADV) &&
 	    !(param->options & BT_LE_ADV_OPT_NO_2M)) {
@@ -2206,6 +2206,9 @@ void bt_hci_le_adv_set_terminated(struct net_buf *buf)
 					bt_addr_copy(&conn->le.resp_addr.a,
 						     &adv->random_addr.a);
 				}
+			} else if (adv->options & BT_LE_ADV_OPT_USE_NRPA) {
+				bt_addr_le_copy(&conn->le.resp_addr,
+						&adv->random_addr);
 			} else {
 				bt_addr_le_copy(&conn->le.resp_addr,
 					&bt_dev.id_addr[conn->id]);

subsys/bluetooth/host/id.c

@@ -329,6 +329,16 @@ int bt_id_set_adv_private_addr(struct bt_le_ext_adv *adv)
 		return -EINVAL;
 	}
 
+	if (IS_ENABLED(CONFIG_BT_PRIVACY) &&
+	    (adv->options & BT_LE_ADV_OPT_USE_NRPA)) {
+		/* The host doesn't support setting NRPAs when BT_PRIVACY=y.
+		 * In that case you probably want to use an RPA anyway.
+		 */
+		LOG_ERR("NRPA not supported when BT_PRIVACY=y");
+
+		return -ENOSYS;
+	}
+
 	if (!(IS_ENABLED(CONFIG_BT_EXT_ADV) &&
 	      BT_DEV_FEAT_LE_EXT_ADV(bt_dev.le.features))) {
 		return bt_id_set_private_addr(adv->id);
@@ -1754,6 +1764,23 @@ int bt_id_set_adv_own_addr(struct bt_le_ext_adv *adv, uint32_t options,
 	/* Set which local identity address we're advertising with */
 	id_addr = &bt_dev.id_addr[adv->id];
 
+	/* Short-circuit to force NRPA usage */
+	if (options & BT_LE_ADV_OPT_USE_NRPA) {
+		if (options & BT_LE_ADV_OPT_USE_IDENTITY) {
+			LOG_ERR("Can't set both IDENTITY & NRPA");
+
+			return -EINVAL;
+		}
+
+		err = bt_id_set_adv_private_addr(adv);
+		if (err) {
+			return err;
+		}
+		*own_addr_type = BT_ADDR_LE_RANDOM;
+
+		return 0;
+	}
+
 	if (options & BT_LE_ADV_OPT_CONNECTABLE) {
 		if (dir_adv && (options & BT_LE_ADV_OPT_DIR_ADDR_RPA) &&
 		    !BT_FEAT_LE_PRIVACY(bt_dev.le.features)) {