Bluetooth: L2CAP_BR: incorrect result returned if config opt unsupported

The `BT_L2CAP_CONF_SUCCESS` is returned as result for the config
req with supported opt.

Result `BT_L2CAP_CONF_UNKNOWN_OPT` should be returned for this case.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>

Author: lylezhu2012

subsys/bluetooth/host/classic/l2cap_br.c

@@ -707,6 +707,13 @@ static void l2cap_br_conf_add_mtu(struct net_buf *buf, const uint16_t mtu)
 	net_buf_add_le16(buf, mtu);
 }
 
+static void l2cap_br_conf_add_opt(struct net_buf *buf, const struct bt_l2cap_conf_opt *opt)
+{
+	net_buf_add_u8(buf, opt->type & BT_L2CAP_CONF_MASK);
+	net_buf_add_u8(buf, opt->len);
+	net_buf_add_mem(buf, opt->data, opt->len);
+}
+
 static void l2cap_br_conf(struct bt_l2cap_chan *chan)
 {
 	struct bt_l2cap_sig_hdr *hdr;
@@ -1235,7 +1242,7 @@ static void l2cap_br_conf_req(struct bt_l2cap_br *l2cap, uint8_t ident,
 	struct bt_l2cap_conf_req *req;
 	struct bt_l2cap_sig_hdr *hdr;
 	struct bt_l2cap_conf_rsp *rsp;
-	struct bt_l2cap_conf_opt *opt;
+	struct bt_l2cap_conf_opt *opt = NULL;
 	uint16_t flags, dcid, opt_len, hint, result = BT_L2CAP_CONF_SUCCESS;
 
 	if (buf->len < sizeof(*req)) {
@@ -1294,6 +1301,7 @@ static void l2cap_br_conf_req(struct bt_l2cap_br *l2cap, uint8_t ident,
 		default:
 			if (!hint) {
 				LOG_DBG("option %u not handled", opt->type);
+				result = BT_L2CAP_CONF_UNKNOWN_OPT;
 				goto send_rsp;
 			}
 
@@ -1322,6 +1330,10 @@ static void l2cap_br_conf_req(struct bt_l2cap_br *l2cap, uint8_t ident,
 	 */
 	if (result == BT_L2CAP_CONF_UNACCEPT) {
 		l2cap_br_conf_add_mtu(buf, BR_CHAN(chan)->tx.mtu);
+	} else if (result == BT_L2CAP_CONF_UNKNOWN_OPT) {
+		if (opt) {
+			l2cap_br_conf_add_opt(buf, opt);
+		}
 	}
 
 	hdr->len = sys_cpu_to_le16(buf->len - sizeof(*hdr));

subsys/bluetooth/host/classic/l2cap_br_internal.h

@@ -72,6 +72,9 @@ struct bt_l2cap_conn_rsp {
 #define BT_L2CAP_CONF_SUCCESS           0x0000
 #define BT_L2CAP_CONF_UNACCEPT          0x0001
 #define BT_L2CAP_CONF_REJECT            0x0002
+#define BT_L2CAP_CONF_UNKNOWN_OPT       0x0003
+#define BT_L2CAP_CONF_PENDING           0x0004
+#define BT_L2CAP_CONF_FLOW_SPEC_REJECT  0x0005
 
 #define BT_L2CAP_CONF_REQ               0x04
 struct bt_l2cap_conf_req {