// Copyright 2019 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.net.neighbor;

using fuchsia.hardware.ethernet;
using fuchsia.net;
using zx;

/// Information on a neighboring device in the local network.
///
/// There are two types of entries available in the neighbor table.
///   1. Dynamic entries are discovered automatically by neighbor discovery
///      protocols (e.g. ARP, NDP). These protocols will attempt to reconfirm
///      reachability with the device once its `state` becomes
///      [`EntryState.stale`].
///   2. Static entries are explicitly added by a user with
///      [`Controller.AddStaticEntry`] and have no expiration. Their `state` is
///      always [`EntryState.static`].
table Entry {
    /// Identifier for the interface used for communicating with the neighbor.
    1: InterfaceID interface;

    /// IP address of the neighbor.
    2: fuchsia.net.IpAddress neighbor;

    /// State of the entry within the Neighbor Unreachability Detection (NUD)
    /// state machine defined by RFC 4861 section 7.3.
    3: EntryState state;

    /// MAC address of the neighboring device's network interface controller.
    /// Absent for dynamic entries in [`EntryState.incomplete`].
    4: fuchsia.hardware.ethernet.MacAddress mac;

    /// Timestamp when this entry has changed `state`.
    5: zx.time updated_at;
};