sdk/fidl/fuchsia.bluetooth.le/l2cap.fidl

// Copyright 2024 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
library fuchsia.bluetooth.le;

using fuchsia.bluetooth as bt;
using zx;

/// The set of parameters for accepting a channel when listening for new channel
/// connections.
///
/// See [`ChannelListenerRegistry/ListenL2cap`].
@available(added=24)
type AcceptedChannelParameters = table {
    /// All channel modes that should be accepted while listening. Must contain
    /// at least one channel mode or the call will fail with
    /// `ZX_ERR_INVALID_ARGS`.
    /// Required.
    1: accepted_channel_modes vector<bt.ChannelMode>:MAX;
    /// Maximum supported packet size for receiving.
    /// Optional. If not provided, the size will be determined by the Bluetooth
    /// system. No guarantees are given regarding the size selected.
    2: max_packet_size uint16;
};

/// Represents a service or protocol that accepts incoming channel requests.
/// Incoming channel requests for the associated PSM will be connected via this
/// protocol. Closing this protocol will also cease accepting any incoming
/// channel requests, but existing established channels will not be affected.
/// Additionally, once this protocol is closed the implementation is free to
/// reuse the PSM that was previously assigned for this instance.
@available(added=24)
open protocol ChannelListener {
    flexible Accept(resource struct {
        channel client_end:bt.Channel;
    }) -> ();
};

/// An identifier for a service that accepts connection-oriented channel
/// connections. Referred to as a (simplified) protocol/service multiplexer
/// in the Bluetooth specification.
@available(added=24)
alias Psm = uint16;

/// Represents the ability to register and accept incoming connections on
/// connection oriented channels.
@available(added=24)
closed protocol ChannelListenerRegistry {
    /// Register a listener for incoming channels. The registry will assign a
    /// PSM value that is unique for the local device, as well as open a
    /// [`ChannelListener`] for accepting incoming channels. In the unlikely
    /// event that all PSMs have been assigned, this call will fail with
    /// `ZX_ERR_NO_RESOURCES`.
    ///
    /// Note that the method of service discovery or advertising is defined by
    /// the service or protocol, so it is the responsibility of the caller to
    /// communicate the assigned PSM to any clients.
    strict ListenL2cap(resource table {
        /// Accepted parameters for the local side of the channel.
        1: parameters AcceptedChannelParameters;
        /// The channel listener protocol to open.
        2: listener client_end:ChannelListener;
    }) -> (table {
        /// PSM assigned by the registry. Guaranteed to be in the `DYNAMIC`
        /// range of PSM values.
        1: psm Psm;
    }) error zx.Status;
};