// Copyright 2018 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;

/// The maximum length of a hostname, as per
/// [RFC 1035 section 2.3.4](https://tools.ietf.org/html/rfc1035#section-2.3.4).
// TODO(https://fxbug.dev/42164951): inline this constant below.
const MAX_HOSTNAME_SIZE uint64 = 255;

/// A hostname.
///
/// Although the maximum length of a domain or hostname is 255 characters,
/// each label within a name must not be longer than 63 characters as per
/// [RFC 1035 section 2.3.4](https://tools.ietf.org/html/rfc1035#section-2.3.4).
/// A label in a host name is the alphanumeric characters or hyphens, seperated
/// by a period (e.g. abc.com has two labels, 'abc' and 'com').
alias Hostname = string:MAX_HOSTNAME_SIZE;

/// A unique non-zero interface identifier.
alias InterfaceId = uint64;

/// IpVersion is an IP version.
type IpVersion = strict enum {
    V4 = 1;
    V6 = 2;
};

/// Ipv4Address is expressed in network byte order, so the most significant byte
/// ("127" in the address "127.0.0.1") will be at index 0.
type Ipv4Address = struct {
    // TODO(https://fxbug.dev/42094982): rename to octets.
    addr array<uint8, 4>;
};

/// Ipv6Address is expressed in network byte order, so the most significant byte
/// ("ff" in the address "ff02::1") will be at index 0.
type Ipv6Address = struct {
    // TODO(https://fxbug.dev/42094982): rename to octets.
    addr array<uint8, 16>;
};

/// Represents an IP address that may be either v4 or v6.
type IpAddress = strict union {
    1: ipv4 Ipv4Address;
    2: ipv6 Ipv6Address;
};

// TODO(https://fxbug.dev/42131655): rename Subnet to AddressWithPrefix when
// binding support is ready, so we don't have to recursively fix all users.
/// An IP address with its subnet prefix length.
type Subnet = struct {
    /// The IPv4 or IPv6 address.
    addr IpAddress;

    /// The number of bits set to 1 in the subnet mask.
    ///
    /// When [`addr`] is [`IpAddress.ipv4`], must be in the range `[0, 32]`.
    /// When [`addr`] is [`IpAddress.ipv6`], must be in the range `[0, 128]`.
    // TODO(https://fxbug.dev/42094982): rename to prefix_length.
    prefix_len uint8;
};

/// An IPv4 address with its subnet prefix length.
type Ipv4AddressWithPrefix = struct {
    /// The IPv4 address.
    addr Ipv4Address;

    /// The prefix length. Must be in the range [0, 32].
    prefix_len uint8;
};

/// An IPv6 address with its subnet prefix length.
type Ipv6AddressWithPrefix = struct {
    /// The IPv6 address.
    addr Ipv6Address;

    /// The prefix length. Must be in the range [0, 128].
    prefix_len uint8;
};

/// A MAC address used to identify a network interface on the data link layer within the network.
type MacAddress = struct {
    octets array<uint8, 6>;
};

/// The metric of a route. Lower metrics indicate higher priority.
alias RouteMetric = uint32;