// NewServer returns an ATT (Attribute Protocol) server.
func NewServer(db *DB, l2c ble.Conn) (*Server, error) {
mtu := l2c.RxMTU()
if mtu < ble.DefaultMTU || mtu > ble.MaxMTU {
return nil, fmt.Errorf("invalid MTU")
}
// Although the rxBuf is initialized with the capacity of rxMTU, it is
// not discovered, and only the default ATT_MTU (23 bytes) of it shall
// be used until remote central request ExchangeMTU.
s := &Server{
conn: &conn{
Conn: l2c,
cccs: make(map[uint16]uint16),
in: make(map[uint16]ble.Notifier),
nn: make(map[uint16]ble.Notifier),
},
db: db,
rxMTU: mtu,
txBuf: make([]byte, ble.DefaultMTU, ble.DefaultMTU),
chNotBuf: make(chan []byte, 1),
chIndBuf: make(chan []byte, 1),
chConfirm: make(chan bool),
dummyRspWriter: ble.NewResponseWriter(nil),
}
s.conn.svr = s
s.chNotBuf <- make([]byte, ble.DefaultMTU, ble.DefaultMTU)
s.chIndBuf <- make([]byte, ble.DefaultMTU, ble.DefaultMTU)
return s, nil
}
