Bluetooth: Classic: L2CAP: Handle multi L2CAP packets of a HCI ACL

In current implementation, if the HCI ACL data length exceeds on L2CAP
packet, the HCI ACL data will be discarded.

Support the case if the transport is classic.

Add a function `bt_br_acl_recv()` to handle the multi L2CAP packets
one by one.

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

Author: lylezhu2012

subsys/bluetooth/host/classic/conn_br.c

@@ -143,3 +143,30 @@ const bt_addr_t *bt_conn_get_dst_br(const struct bt_conn *conn)
 
 	return &conn->br.dst;
 }
+
+void bt_br_acl_recv(struct bt_conn *conn, struct net_buf *buf, bool complete)
+{
+	uint16_t acl_total_len;
+	struct bt_l2cap_hdr *hdr;
+	struct net_buf_simple_state state;
+
+	do {
+		net_buf_simple_save(&buf->b, &state);
+
+		hdr = (void *)buf->data;
+		acl_total_len = sys_le16_to_cpu(hdr->len) + sizeof(*hdr);
+		if (buf->len > acl_total_len) {
+			LOG_DBG("Multiple L2CAP packet (%u > %u)", buf->len, acl_total_len);
+			buf->len = acl_total_len;
+		} else if (buf->len < acl_total_len) {
+			LOG_ERR("Short packet (%u < %u)", buf->len, acl_total_len);
+			break;
+		}
+		bt_l2cap_recv(conn, net_buf_ref(buf), complete);
+
+		net_buf_simple_restore(&buf->b, &state);
+		net_buf_pull(buf, acl_total_len);
+	} while (buf->len > 0);
+
+	net_buf_unref(buf);
+}

subsys/bluetooth/host/classic/conn_br_internal.h

@@ -10,3 +10,5 @@
  */
 
 int bt_hci_connect_br_cancel(struct bt_conn *conn);
+
+void bt_br_acl_recv(struct bt_conn *conn, struct net_buf *buf, bool complete);

subsys/bluetooth/host/conn.c

@@ -471,7 +471,7 @@ static void bt_acl_recv(struct bt_conn *conn, struct net_buf *buf, uint8_t flags
 
 	net_buf_unref(buf);
 
-	if (conn->rx->len > acl_total_len) {
+	if ((conn->type != BT_CONN_TYPE_BR) && (conn->rx->len > acl_total_len)) {
 		LOG_ERR("ACL len mismatch (%u > %u)", conn->rx->len, acl_total_len);
 		bt_conn_reset_rx_state(conn);
 		return;
@@ -484,7 +484,11 @@ static void bt_acl_recv(struct bt_conn *conn, struct net_buf *buf, uint8_t flags
 	__ASSERT(buf->ref == 1, "buf->ref %d", buf->ref);
 
 	LOG_DBG("Successfully parsed %u byte L2CAP packet", buf->len);
-	bt_l2cap_recv(conn, buf, true);
+	if (IS_ENABLED(CONFIG_BT_CLASSIC) && (conn->type == BT_CONN_TYPE_BR)) {
+		bt_br_acl_recv(conn, buf, true);
+	} else {
+		bt_l2cap_recv(conn, buf, true);
+	}
 }
 
 void bt_conn_recv(struct bt_conn *conn, struct net_buf *buf, uint8_t flags)