ip_addr.rs - source
Description: Source of the Rust file `library/core/src/net/ip_addr.rs`.

#
core/net/
ip_addr.rs

    1use super::display_buffer::DisplayBuffer;
    2use crate::cmp::Ordering;
    3use crate::fmt::{self, Write};
    4use crate::hash::{Hash, Hasher};
    5use crate::mem::transmute;
    6use crate::ops::{BitAnd, BitAndAssign, BitOr, BitOrAssign, Not};
    7
    8/// An IP address, either IPv4 or IPv6.
    9///
    10/// This enum can contain either an [`Ipv4Addr`] or an [`Ipv6Addr`], see their
    11/// respective documentation for more details.
    12///
    13/// # Examples
    14///
    15/// ```
    16/// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    17///
    18/// let localhost_v4 = IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1));
    19/// let localhost_v6 = IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1));
    20///
    21/// assert_eq!("127.0.0.1".parse(), Ok(localhost_v4));
    22/// assert_eq!("::1".parse(), Ok(localhost_v6));
    23///
    24/// assert_eq!(localhost_v4.is_ipv6(), false);
    25/// assert_eq!(localhost_v4.is_ipv4(), true);
    26/// ```
    27#[rustc_diagnostic_item = "IpAddr"]
    28#[stable(feature = "ip_addr", since = "1.7.0")]
    29#[derive(Copy, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
    30pub enum IpAddr {
    31    /// An IPv4 address.
    32    #[stable(feature = "ip_addr", since = "1.7.0")]
    33    V4(#[stable(feature = "ip_addr", since = "1.7.0")] Ipv4Addr),
    34    /// An IPv6 address.
    35    #[stable(feature = "ip_addr", since = "1.7.0")]
    36    V6(#[stable(feature = "ip_addr", since = "1.7.0")] Ipv6Addr),
    37}
    38
    39/// An IPv4 address.
    40///
    41/// IPv4 addresses are defined as 32-bit integers in [IETF RFC 791].
    42/// They are usually represented as four octets.
    43///
    44/// See [`IpAddr`] for a type encompassing both IPv4 and IPv6 addresses.
    45///
    46/// [IETF RFC 791]: https://tools.ietf.org/html/rfc791
    47///
    48/// # Textual representation
    49///
    50/// `Ipv4Addr` provides a [`FromStr`] implementation. The four octets are in decimal
    51/// notation, divided by `.` (this is called "dot-decimal notation").
    52/// Notably, octal numbers (which are indicated with a leading `0`) and hexadecimal numbers (which
    53/// are indicated with a leading `0x`) are not allowed per [IETF RFC 6943].
    54///
    55/// [IETF RFC 6943]: https://tools.ietf.org/html/rfc6943#section-3.1.1
    56/// [`FromStr`]: crate::str::FromStr
    57///
    58/// # Examples
    59///
    60/// ```
    61/// use std::net::Ipv4Addr;
    62///
    63/// let localhost = Ipv4Addr::new(127, 0, 0, 1);
    64/// assert_eq!("127.0.0.1".parse(), Ok(localhost));
    65/// assert_eq!(localhost.is_loopback(), true);
    66/// assert!("012.004.002.000".parse::<Ipv4Addr>().is_err()); // all octets are in octal
    67/// assert!("0000000.0.0.0".parse::<Ipv4Addr>().is_err()); // first octet is a zero in octal
    68/// assert!("0xcb.0x0.0x71.0x00".parse::<Ipv4Addr>().is_err()); // all octets are in hex
    69/// ```
    70#[rustc_diagnostic_item = "Ipv4Addr"]
    71#[derive(Copy, Clone, PartialEq, Eq)]
    72#[stable(feature = "rust1", since = "1.0.0")]
    73pub struct Ipv4Addr {
    74    octets: [u8; 4],
    75}
    76
    77#[stable(feature = "rust1", since = "1.0.0")]
    78impl Hash for Ipv4Addr {
    79    fn hash<H: Hasher>(&self, state: &mut H) {
    80        // Hashers are often more efficient at hashing a fixed-width integer
    81        // than a bytestring, so convert before hashing. We don't use to_bits()
    82        // here as that may involve a byteswap which is unnecessary.
    83        u32::from_ne_bytes(self.octets).hash(state);
    84    }
    85}
    86
    87/// An IPv6 address.
    88///
    89/// IPv6 addresses are defined as 128-bit integers in [IETF RFC 4291].
    90/// They are usually represented as eight 16-bit segments.
    91///
    92/// [IETF RFC 4291]: https://tools.ietf.org/html/rfc4291
    93///
    94/// # Embedding IPv4 Addresses
    95///
    96/// See [`IpAddr`] for a type encompassing both IPv4 and IPv6 addresses.
    97///
    98/// To assist in the transition from IPv4 to IPv6 two types of IPv6 addresses that embed an IPv4 address were defined:
    99/// IPv4-compatible and IPv4-mapped addresses. Of these IPv4-compatible addresses have been officially deprecated.
    100///
    101/// Both types of addresses are not assigned any special meaning by this implementation,
    102/// other than what the relevant standards prescribe. This means that an address like `::ffff:127.0.0.1`,
    103/// while representing an IPv4 loopback address, is not itself an IPv6 loopback address; only `::1` is.
    104/// To handle these so called "IPv4-in-IPv6" addresses, they have to first be converted to their canonical IPv4 address.
    105///
    106/// ### IPv4-Compatible IPv6 Addresses
    107///
    108/// IPv4-compatible IPv6 addresses are defined in [IETF RFC 4291 Section 2.5.5.1], and have been officially deprecated.
    109/// The RFC describes the format of an "IPv4-Compatible IPv6 address" as follows:
    110///
    111/// ```text
    112/// |                80 bits               | 16 |      32 bits        |
    113/// +--------------------------------------+--------------------------+
    114/// |0000..............................0000|0000|    IPv4 address     |
    115/// +--------------------------------------+----+---------------------+
    116/// ```
    117/// So `::a.b.c.d` would be an IPv4-compatible IPv6 address representing the IPv4 address `a.b.c.d`.
    118///
    119/// To convert from an IPv4 address to an IPv4-compatible IPv6 address, use [`Ipv4Addr::to_ipv6_compatible`].
    120/// Use [`Ipv6Addr::to_ipv4`] to convert an IPv4-compatible IPv6 address to the canonical IPv4 address.
    121///
    122/// [IETF RFC 4291 Section 2.5.5.1]: https://datatracker.ietf.org/doc/html/rfc4291#section-2.5.5.1
    123///
    124/// ### IPv4-Mapped IPv6 Addresses
    125///
    126/// IPv4-mapped IPv6 addresses are defined in [IETF RFC 4291 Section 2.5.5.2].
    127/// The RFC describes the format of an "IPv4-Mapped IPv6 address" as follows:
    128///
    129/// ```text
    130/// |                80 bits               | 16 |      32 bits        |
    131/// +--------------------------------------+--------------------------+
    132/// |0000..............................0000|FFFF|    IPv4 address     |
    133/// +--------------------------------------+----+---------------------+
    134/// ```
    135/// So `::ffff:a.b.c.d` would be an IPv4-mapped IPv6 address representing the IPv4 address `a.b.c.d`.
    136///
    137/// To convert from an IPv4 address to an IPv4-mapped IPv6 address, use [`Ipv4Addr::to_ipv6_mapped`].
    138/// Use [`Ipv6Addr::to_ipv4`] to convert an IPv4-mapped IPv6 address to the canonical IPv4 address.
    139/// Note that this will also convert the IPv6 loopback address `::1` to `0.0.0.1`. Use
    140/// [`Ipv6Addr::to_ipv4_mapped`] to avoid this.
    141///
    142/// [IETF RFC 4291 Section 2.5.5.2]: https://datatracker.ietf.org/doc/html/rfc4291#section-2.5.5.2
    143///
    144/// # Textual representation
    145///
    146/// `Ipv6Addr` provides a [`FromStr`] implementation. There are many ways to represent
    147/// an IPv6 address in text, but in general, each segments is written in hexadecimal
    148/// notation, and segments are separated by `:`. For more information, see
    149/// [IETF RFC 5952].
    150///
    151/// [`FromStr`]: crate::str::FromStr
    152/// [IETF RFC 5952]: https://tools.ietf.org/html/rfc5952
    153///
    154/// # Examples
    155///
    156/// ```
    157/// use std::net::Ipv6Addr;
    158///
    159/// let localhost = Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1);
    160/// assert_eq!("::1".parse(), Ok(localhost));
    161/// assert_eq!(localhost.is_loopback(), true);
    162/// ```
    163#[rustc_diagnostic_item = "Ipv6Addr"]
    164#[derive(Copy, Clone, PartialEq, Eq)]
    165#[stable(feature = "rust1", since = "1.0.0")]
    166pub struct Ipv6Addr {
    167    octets: [u8; 16],
    168}
    169
    170#[stable(feature = "rust1", since = "1.0.0")]
    171impl Hash for Ipv6Addr {
    172    fn hash<H: Hasher>(&self, state: &mut H) {
    173        // Hashers are often more efficient at hashing a fixed-width integer
    174        // than a bytestring, so convert before hashing. We don't use to_bits()
    175        // here as that may involve unnecessary byteswaps.
    176        u128::from_ne_bytes(self.octets).hash(state);
    177    }
    178}
    179
    180/// Scope of an [IPv6 multicast address] as defined in [IETF RFC 7346 section 2].
    181///
    182/// # Stability Guarantees
    183///
    184/// Not all possible values for a multicast scope have been assigned.
    185/// Future RFCs may introduce new scopes, which will be added as variants to this enum;
    186/// because of this the enum is marked as `#[non_exhaustive]`.
    187///
    188/// # Examples
    189/// ```
    190/// #![feature(ip)]
    191///
    192/// use std::net::Ipv6Addr;
    193/// use std::net::Ipv6MulticastScope::*;
    194///
    195/// // An IPv6 multicast address with global scope (`ff0e::`).
    196/// let address = Ipv6Addr::new(0xff0e, 0, 0, 0, 0, 0, 0, 0);
    197///
    198/// // Will print "Global scope".
    199/// match address.multicast_scope() {
    200///     Some(InterfaceLocal) => println!("Interface-Local scope"),
    201///     Some(LinkLocal) => println!("Link-Local scope"),
    202///     Some(RealmLocal) => println!("Realm-Local scope"),
    203///     Some(AdminLocal) => println!("Admin-Local scope"),
    204///     Some(SiteLocal) => println!("Site-Local scope"),
    205///     Some(OrganizationLocal) => println!("Organization-Local scope"),
    206///     Some(Global) => println!("Global scope"),
    207///     Some(_) => println!("Unknown scope"),
    208///     None => println!("Not a multicast address!")
    209/// }
    210///
    211/// ```
    212///
    213/// [IPv6 multicast address]: Ipv6Addr
    214/// [IETF RFC 7346 section 2]: https://tools.ietf.org/html/rfc7346#section-2
    215#[derive(Copy, PartialEq, Eq, Clone, Hash, Debug)]
    216#[unstable(feature = "ip", issue = "27709")]
    217#[non_exhaustive]
    218pub enum Ipv6MulticastScope {
    219    /// Interface-Local scope.
    220    InterfaceLocal,
    221    /// Link-Local scope.
    222    LinkLocal,
    223    /// Realm-Local scope.
    224    RealmLocal,
    225    /// Admin-Local scope.
    226    AdminLocal,
    227    /// Site-Local scope.
    228    SiteLocal,
    229    /// Organization-Local scope.
    230    OrganizationLocal,
    231    /// Global scope.
    232    Global,
    233}
    234
    235impl IpAddr {
    236    /// Returns [`true`] for the special 'unspecified' address.
    237    ///
    238    /// See the documentation for [`Ipv4Addr::is_unspecified()`] and
    239    /// [`Ipv6Addr::is_unspecified()`] for more details.
    240    ///
    241    /// # Examples
    242    ///
    243    /// ```
    244    /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    245    ///
    246    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(0, 0, 0, 0)).is_unspecified(), true);
    247    /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0)).is_unspecified(), true);
    248    /// ```
    249    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    250    #[stable(feature = "ip_shared", since = "1.12.0")]
    251    #[must_use]
    252    #[inline]
    253    pub const fn is_unspecified(&self) -> bool {
    254        match self {
    255            IpAddr::V4(ip) => ip.is_unspecified(),
    256            IpAddr::V6(ip) => ip.is_unspecified(),
    257        }
    258    }
    259
    260    /// Returns [`true`] if this is a loopback address.
    261    ///
    262    /// See the documentation for [`Ipv4Addr::is_loopback()`] and
    263    /// [`Ipv6Addr::is_loopback()`] for more details.
    264    ///
    265    /// # Examples
    266    ///
    267    /// ```
    268    /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    269    ///
    270    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)).is_loopback(), true);
    271    /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0x1)).is_loopback(), true);
    272    /// ```
    273    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    274    #[stable(feature = "ip_shared", since = "1.12.0")]
    275    #[must_use]
    276    #[inline]
    277    pub const fn is_loopback(&self) -> bool {
    278        match self {
    279            IpAddr::V4(ip) => ip.is_loopback(),
    280            IpAddr::V6(ip) => ip.is_loopback(),
    281        }
    282    }
    283
    284    /// Returns [`true`] if the address appears to be globally routable.
    285    ///
    286    /// See the documentation for [`Ipv4Addr::is_global()`] and
    287    /// [`Ipv6Addr::is_global()`] for more details.
    288    ///
    289    /// # Examples
    290    ///
    291    /// ```
    292    /// #![feature(ip)]
    293    ///
    294    /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    295    ///
    296    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(80, 9, 12, 3)).is_global(), true);
    297    /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0, 0, 0x1c9, 0, 0, 0xafc8, 0, 0x1)).is_global(), true);
    298    /// ```
    299    #[unstable(feature = "ip", issue = "27709")]
    300    #[must_use]
    301    #[inline]
    302    pub const fn is_global(&self) -> bool {
    303        match self {
    304            IpAddr::V4(ip) => ip.is_global(),
    305            IpAddr::V6(ip) => ip.is_global(),
    306        }
    307    }
    308
    309    /// Returns [`true`] if this is a multicast address.
    310    ///
    311    /// See the documentation for [`Ipv4Addr::is_multicast()`] and
    312    /// [`Ipv6Addr::is_multicast()`] for more details.
    313    ///
    314    /// # Examples
    315    ///
    316    /// ```
    317    /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    318    ///
    319    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(224, 254, 0, 0)).is_multicast(), true);
    320    /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0xff00, 0, 0, 0, 0, 0, 0, 0)).is_multicast(), true);
    321    /// ```
    322    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    323    #[stable(feature = "ip_shared", since = "1.12.0")]
    324    #[must_use]
    325    #[inline]
    326    pub const fn is_multicast(&self) -> bool {
    327        match self {
    328            IpAddr::V4(ip) => ip.is_multicast(),
    329            IpAddr::V6(ip) => ip.is_multicast(),
    330        }
    331    }
    332
    333    /// Returns [`true`] if this address is in a range designated for documentation.
    334    ///
    335    /// See the documentation for [`Ipv4Addr::is_documentation()`] and
    336    /// [`Ipv6Addr::is_documentation()`] for more details.
    337    ///
    338    /// # Examples
    339    ///
    340    /// ```
    341    /// #![feature(ip)]
    342    ///
    343    /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    344    ///
    345    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(203, 0, 113, 6)).is_documentation(), true);
    346    /// assert_eq!(
    347    ///     IpAddr::V6(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0)).is_documentation(),
    348    ///     true
    349    /// );
    350    /// ```
    351    #[unstable(feature = "ip", issue = "27709")]
    352    #[must_use]
    353    #[inline]
    354    pub const fn is_documentation(&self) -> bool {
    355        match self {
    356            IpAddr::V4(ip) => ip.is_documentation(),
    357            IpAddr::V6(ip) => ip.is_documentation(),
    358        }
    359    }
    360
    361    /// Returns [`true`] if this address is in a range designated for benchmarking.
    362    ///
    363    /// See the documentation for [`Ipv4Addr::is_benchmarking()`] and
    364    /// [`Ipv6Addr::is_benchmarking()`] for more details.
    365    ///
    366    /// # Examples
    367    ///
    368    /// ```
    369    /// #![feature(ip)]
    370    ///
    371    /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    372    ///
    373    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(198, 19, 255, 255)).is_benchmarking(), true);
    374    /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0x2001, 0x2, 0, 0, 0, 0, 0, 0)).is_benchmarking(), true);
    375    /// ```
    376    #[unstable(feature = "ip", issue = "27709")]
    377    #[must_use]
    378    #[inline]
    379    pub const fn is_benchmarking(&self) -> bool {
    380        match self {
    381            IpAddr::V4(ip) => ip.is_benchmarking(),
    382            IpAddr::V6(ip) => ip.is_benchmarking(),
    383        }
    384    }
    385
    386    /// Returns [`true`] if this address is an [`IPv4` address], and [`false`]
    387    /// otherwise.
    388    ///
    389    /// [`IPv4` address]: IpAddr::V4
    390    ///
    391    /// # Examples
    392    ///
    393    /// ```
    394    /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    395    ///
    396    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(203, 0, 113, 6)).is_ipv4(), true);
    397    /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0)).is_ipv4(), false);
    398    /// ```
    399    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    400    #[stable(feature = "ipaddr_checker", since = "1.16.0")]
    401    #[must_use]
    402    #[inline]
    403    pub const fn is_ipv4(&self) -> bool {
    404        matches!(self, IpAddr::V4(_))
    405    }
    406
    407    /// Returns [`true`] if this address is an [`IPv6` address], and [`false`]
    408    /// otherwise.
    409    ///
    410    /// [`IPv6` address]: IpAddr::V6
    411    ///
    412    /// # Examples
    413    ///
    414    /// ```
    415    /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    416    ///
    417    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(203, 0, 113, 6)).is_ipv6(), false);
    418    /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0)).is_ipv6(), true);
    419    /// ```
    420    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    421    #[stable(feature = "ipaddr_checker", since = "1.16.0")]
    422    #[must_use]
    423    #[inline]
    424    pub const fn is_ipv6(&self) -> bool {
    425        matches!(self, IpAddr::V6(_))
    426    }
    427
    428    /// Converts this address to an `IpAddr::V4` if it is an IPv4-mapped IPv6
    429    /// address, otherwise returns `self` as-is.
    430    ///
    431    /// # Examples
    432    ///
    433    /// ```
    434    /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
    435    ///
    436    /// let localhost_v4 = Ipv4Addr::new(127, 0, 0, 1);
    437    ///
    438    /// assert_eq!(IpAddr::V4(localhost_v4).to_canonical(), localhost_v4);
    439    /// assert_eq!(IpAddr::V6(localhost_v4.to_ipv6_mapped()).to_canonical(), localhost_v4);
    440    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)).to_canonical().is_loopback(), true);
    441    /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0x7f00, 0x1)).is_loopback(), false);
    442    /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0x7f00, 0x1)).to_canonical().is_loopback(), true);
    443    /// ```
    444    #[inline]
    445    #[must_use = "this returns the result of the operation, \
    446                  without modifying the original"]
    447    #[stable(feature = "ip_to_canonical", since = "1.75.0")]
    448    #[rustc_const_stable(feature = "ip_to_canonical", since = "1.75.0")]
    449    pub const fn to_canonical(&self) -> IpAddr {
    450        match self {
    451            IpAddr::V4(_) => *self,
    452            IpAddr::V6(v6) => v6.to_canonical(),
    453        }
    454    }
    455
    456    /// Returns the eight-bit integers this address consists of as a slice.
    457    ///
    458    /// # Examples
    459    ///
    460    /// ```
    461    /// #![feature(ip_as_octets)]
    462    ///
    463    /// use std::net::{Ipv4Addr, Ipv6Addr, IpAddr};
    464    ///
    465    /// assert_eq!(IpAddr::V4(Ipv4Addr::LOCALHOST).as_octets(), &[127, 0, 0, 1]);
    466    /// assert_eq!(IpAddr::V6(Ipv6Addr::LOCALHOST).as_octets(),
    467    ///            &[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1])
    468    /// ```
    469    #[unstable(feature = "ip_as_octets", issue = "137259")]
    470    #[inline]
    471    pub const fn as_octets(&self) -> &[u8] {
    472        match self {
    473            IpAddr::V4(ip) => ip.as_octets().as_slice(),
    474            IpAddr::V6(ip) => ip.as_octets().as_slice(),
    475        }
    476    }
    477}
    478
    479impl Ipv4Addr {
    480    /// Creates a new IPv4 address from four eight-bit octets.
    481    ///
    482    /// The result will represent the IP address `a`.`b`.`c`.`d`.
    483    ///
    484    /// # Examples
    485    ///
    486    /// ```
    487    /// use std::net::Ipv4Addr;
    488    ///
    489    /// let addr = Ipv4Addr::new(127, 0, 0, 1);
    490    /// ```
    491    #[rustc_const_stable(feature = "const_ip_32", since = "1.32.0")]
    492    #[stable(feature = "rust1", since = "1.0.0")]
    493    #[must_use]
    494    #[inline]
    495    pub const fn new(a: u8, b: u8, c: u8, d: u8) -> Ipv4Addr {
    496        Ipv4Addr { octets: [a, b, c, d] }
    497    }
    498
    499    /// The size of an IPv4 address in bits.
    500    ///
    501    /// # Examples
    502    ///
    503    /// ```
    504    /// use std::net::Ipv4Addr;
    505    ///
    506    /// assert_eq!(Ipv4Addr::BITS, 32);
    507    /// ```
    508    #[stable(feature = "ip_bits", since = "1.80.0")]
    509    pub const BITS: u32 = 32;
    510
    511    /// Converts an IPv4 address into a `u32` representation using native byte order.
    512    ///
    513    /// Although IPv4 addresses are big-endian, the `u32` value will use the target platform's
    514    /// native byte order. That is, the `u32` value is an integer representation of the IPv4
    515    /// address and not an integer interpretation of the IPv4 address's big-endian bitstring. This
    516    /// means that the `u32` value masked with `0xffffff00` will set the last octet in the address
    517    /// to 0, regardless of the target platform's endianness.
    518    ///
    519    /// # Examples
    520    ///
    521    /// ```
    522    /// use std::net::Ipv4Addr;
    523    ///
    524    /// let addr = Ipv4Addr::new(0x12, 0x34, 0x56, 0x78);
    525    /// assert_eq!(0x12345678, addr.to_bits());
    526    /// ```
    527    ///
    528    /// ```
    529    /// use std::net::Ipv4Addr;
    530    ///
    531    /// let addr = Ipv4Addr::new(0x12, 0x34, 0x56, 0x78);
    532    /// let addr_bits = addr.to_bits() & 0xffffff00;
    533    /// assert_eq!(Ipv4Addr::new(0x12, 0x34, 0x56, 0x00), Ipv4Addr::from_bits(addr_bits));
    534    ///
    535    /// ```
    536    #[rustc_const_stable(feature = "ip_bits", since = "1.80.0")]
    537    #[stable(feature = "ip_bits", since = "1.80.0")]
    538    #[must_use]
    539    #[inline]
    540    pub const fn to_bits(self) -> u32 {
    541        u32::from_be_bytes(self.octets)
    542    }
    543
    544    /// Converts a native byte order `u32` into an IPv4 address.
    545    ///
    546    /// See [`Ipv4Addr::to_bits`] for an explanation on endianness.
    547    ///
    548    /// # Examples
    549    ///
    550    /// ```
    551    /// use std::net::Ipv4Addr;
    552    ///
    553    /// let addr = Ipv4Addr::from_bits(0x12345678);
    554    /// assert_eq!(Ipv4Addr::new(0x12, 0x34, 0x56, 0x78), addr);
    555    /// ```
    556    #[rustc_const_stable(feature = "ip_bits", since = "1.80.0")]
    557    #[stable(feature = "ip_bits", since = "1.80.0")]
    558    #[must_use]
    559    #[inline]
    560    pub const fn from_bits(bits: u32) -> Ipv4Addr {
    561        Ipv4Addr { octets: bits.to_be_bytes() }
    562    }
    563
    564    /// An IPv4 address with the address pointing to localhost: `127.0.0.1`
    565    ///
    566    /// # Examples
    567    ///
    568    /// ```
    569    /// use std::net::Ipv4Addr;
    570    ///
    571    /// let addr = Ipv4Addr::LOCALHOST;
    572    /// assert_eq!(addr, Ipv4Addr::new(127, 0, 0, 1));
    573    /// ```
    574    #[stable(feature = "ip_constructors", since = "1.30.0")]
    575    pub const LOCALHOST: Self = Ipv4Addr::new(127, 0, 0, 1);
    576
    577    /// An IPv4 address representing an unspecified address: `0.0.0.0`
    578    ///
    579    /// This corresponds to the constant `INADDR_ANY` in other languages.
    580    ///
    581    /// # Examples
    582    ///
    583    /// ```
    584    /// use std::net::Ipv4Addr;
    585    ///
    586    /// let addr = Ipv4Addr::UNSPECIFIED;
    587    /// assert_eq!(addr, Ipv4Addr::new(0, 0, 0, 0));
    588    /// ```
    589    #[doc(alias = "INADDR_ANY")]
    590    #[stable(feature = "ip_constructors", since = "1.30.0")]
    591    pub const UNSPECIFIED: Self = Ipv4Addr::new(0, 0, 0, 0);
    592
    593    /// An IPv4 address representing the broadcast address: `255.255.255.255`.
    594    ///
    595    /// # Examples
    596    ///
    597    /// ```
    598    /// use std::net::Ipv4Addr;
    599    ///
    600    /// let addr = Ipv4Addr::BROADCAST;
    601    /// assert_eq!(addr, Ipv4Addr::new(255, 255, 255, 255));
    602    /// ```
    603    #[stable(feature = "ip_constructors", since = "1.30.0")]
    604    pub const BROADCAST: Self = Ipv4Addr::new(255, 255, 255, 255);
    605
    606    /// Returns the four eight-bit integers that make up this address.
    607    ///
    608    /// # Examples
    609    ///
    610    /// ```
    611    /// use std::net::Ipv4Addr;
    612    ///
    613    /// let addr = Ipv4Addr::new(127, 0, 0, 1);
    614    /// assert_eq!(addr.octets(), [127, 0, 0, 1]);
    615    /// ```
    616    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    617    #[stable(feature = "rust1", since = "1.0.0")]
    618    #[must_use]
    619    #[inline]
    620    pub const fn octets(&self) -> [u8; 4] {
    621        self.octets
    622    }
    623
    624    /// Creates an `Ipv4Addr` from a four element byte array.
    625    ///
    626    /// # Examples
    627    ///
    628    /// ```
    629    /// use std::net::Ipv4Addr;
    630    ///
    631    /// let addr = Ipv4Addr::from_octets([13u8, 12u8, 11u8, 10u8]);
    632    /// assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);
    633    /// ```
    634    #[stable(feature = "ip_from", since = "1.91.0")]
    635    #[rustc_const_stable(feature = "ip_from", since = "1.91.0")]
    636    #[must_use]
    637    #[inline]
    638    pub const fn from_octets(octets: [u8; 4]) -> Ipv4Addr {
    639        Ipv4Addr { octets }
    640    }
    641
    642    /// Returns the four eight-bit integers that make up this address
    643    /// as a slice.
    644    ///
    645    /// # Examples
    646    ///
    647    /// ```
    648    /// #![feature(ip_as_octets)]
    649    ///
    650    /// use std::net::Ipv4Addr;
    651    ///
    652    /// let addr = Ipv4Addr::new(127, 0, 0, 1);
    653    /// assert_eq!(addr.as_octets(), &[127, 0, 0, 1]);
    654    /// ```
    655    #[unstable(feature = "ip_as_octets", issue = "137259")]
    656    #[inline]
    657    pub const fn as_octets(&self) -> &[u8; 4] {
    658        &self.octets
    659    }
    660
    661    /// Returns [`true`] for the special 'unspecified' address (`0.0.0.0`).
    662    ///
    663    /// This property is defined in _UNIX Network Programming, Second Edition_,
    664    /// W. Richard Stevens, p. 891; see also [ip7].
    665    ///
    666    /// [ip7]: https://man7.org/linux/man-pages/man7/ip.7.html
    667    ///
    668    /// # Examples
    669    ///
    670    /// ```
    671    /// use std::net::Ipv4Addr;
    672    ///
    673    /// assert_eq!(Ipv4Addr::new(0, 0, 0, 0).is_unspecified(), true);
    674    /// assert_eq!(Ipv4Addr::new(45, 22, 13, 197).is_unspecified(), false);
    675    /// ```
    676    #[rustc_const_stable(feature = "const_ip_32", since = "1.32.0")]
    677    #[stable(feature = "ip_shared", since = "1.12.0")]
    678    #[must_use]
    679    #[inline]
    680    pub const fn is_unspecified(&self) -> bool {
    681        u32::from_be_bytes(self.octets) == 0
    682    }
    683
    684    /// Returns [`true`] if this is a loopback address (`127.0.0.0/8`).
    685    ///
    686    /// This property is defined by [IETF RFC 1122].
    687    ///
    688    /// [IETF RFC 1122]: https://tools.ietf.org/html/rfc1122
    689    ///
    690    /// # Examples
    691    ///
    692    /// ```
    693    /// use std::net::Ipv4Addr;
    694    ///
    695    /// assert_eq!(Ipv4Addr::new(127, 0, 0, 1).is_loopback(), true);
    696    /// assert_eq!(Ipv4Addr::new(45, 22, 13, 197).is_loopback(), false);
    697    /// ```
    698    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    699    #[stable(since = "1.7.0", feature = "ip_17")]
    700    #[must_use]
    701    #[inline]
    702    pub const fn is_loopback(&self) -> bool {
    703        self.octets()[0] == 127
    704    }
    705
    706    /// Returns [`true`] if this is a private address.
    707    ///
    708    /// The private address ranges are defined in [IETF RFC 1918] and include:
    709    ///
    710    ///  - `10.0.0.0/8`
    711    ///  - `172.16.0.0/12`
    712    ///  - `192.168.0.0/16`
    713    ///
    714    /// [IETF RFC 1918]: https://tools.ietf.org/html/rfc1918
    715    ///
    716    /// # Examples
    717    ///
    718    /// ```
    719    /// use std::net::Ipv4Addr;
    720    ///
    721    /// assert_eq!(Ipv4Addr::new(10, 0, 0, 1).is_private(), true);
    722    /// assert_eq!(Ipv4Addr::new(10, 10, 10, 10).is_private(), true);
    723    /// assert_eq!(Ipv4Addr::new(172, 16, 10, 10).is_private(), true);
    724    /// assert_eq!(Ipv4Addr::new(172, 29, 45, 14).is_private(), true);
    725    /// assert_eq!(Ipv4Addr::new(172, 32, 0, 2).is_private(), false);
    726    /// assert_eq!(Ipv4Addr::new(192, 168, 0, 2).is_private(), true);
    727    /// assert_eq!(Ipv4Addr::new(192, 169, 0, 2).is_private(), false);
    728    /// ```
    729    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    730    #[stable(since = "1.7.0", feature = "ip_17")]
    731    #[must_use]
    732    #[inline]
    733    pub const fn is_private(&self) -> bool {
    734        match self.octets() {
    735            [10, ..] => true,
    736            [172, b, ..] if b >= 16 && b <= 31 => true,
    737            [192, 168, ..] => true,
    738            _ => false,
    739        }
    740    }
    741
    742    /// Returns [`true`] if the address is link-local (`169.254.0.0/16`).
    743    ///
    744    /// This property is defined by [IETF RFC 3927].
    745    ///
    746    /// [IETF RFC 3927]: https://tools.ietf.org/html/rfc3927
    747    ///
    748    /// # Examples
    749    ///
    750    /// ```
    751    /// use std::net::Ipv4Addr;
    752    ///
    753    /// assert_eq!(Ipv4Addr::new(169, 254, 0, 0).is_link_local(), true);
    754    /// assert_eq!(Ipv4Addr::new(169, 254, 10, 65).is_link_local(), true);
    755    /// assert_eq!(Ipv4Addr::new(16, 89, 10, 65).is_link_local(), false);
    756    /// ```
    757    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    758    #[stable(since = "1.7.0", feature = "ip_17")]
    759    #[must_use]
    760    #[inline]
    761    pub const fn is_link_local(&self) -> bool {
    762        matches!(self.octets(), [169, 254, ..])
    763    }
    764
    765    /// Returns [`true`] if the address appears to be globally reachable
    766    /// as specified by the [IANA IPv4 Special-Purpose Address Registry].
    767    ///
    768    /// Whether or not an address is practically reachable will depend on your
    769    /// network configuration. Most IPv4 addresses are globally reachable, unless
    770    /// they are specifically defined as *not* globally reachable.
    771    ///
    772    /// Non-exhaustive list of notable addresses that are not globally reachable:
    773    ///
    774    /// - The [unspecified address] ([`is_unspecified`](Ipv4Addr::is_unspecified))
    775    /// - Addresses reserved for private use ([`is_private`](Ipv4Addr::is_private))
    776    /// - Addresses in the shared address space ([`is_shared`](Ipv4Addr::is_shared))
    777    /// - Loopback addresses ([`is_loopback`](Ipv4Addr::is_loopback))
    778    /// - Link-local addresses ([`is_link_local`](Ipv4Addr::is_link_local))
    779    /// - Addresses reserved for documentation ([`is_documentation`](Ipv4Addr::is_documentation))
    780    /// - Addresses reserved for benchmarking ([`is_benchmarking`](Ipv4Addr::is_benchmarking))
    781    /// - Reserved addresses ([`is_reserved`](Ipv4Addr::is_reserved))
    782    /// - The [broadcast address] ([`is_broadcast`](Ipv4Addr::is_broadcast))
    783    ///
    784    /// For the complete overview of which addresses are globally reachable, see the table at the [IANA IPv4 Special-Purpose Address Registry].
    785    ///
    786    /// [IANA IPv4 Special-Purpose Address Registry]: https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml
    787    /// [unspecified address]: Ipv4Addr::UNSPECIFIED
    788    /// [broadcast address]: Ipv4Addr::BROADCAST
    789    ///
    790    /// # Examples
    791    ///
    792    /// ```
    793    /// #![feature(ip)]
    794    ///
    795    /// use std::net::Ipv4Addr;
    796    ///
    797    /// // Most IPv4 addresses are globally reachable:
    798    /// assert_eq!(Ipv4Addr::new(80, 9, 12, 3).is_global(), true);
    799    ///
    800    /// // However some addresses have been assigned a special meaning
    801    /// // that makes them not globally reachable. Some examples are:
    802    ///
    803    /// // The unspecified address (`0.0.0.0`)
    804    /// assert_eq!(Ipv4Addr::UNSPECIFIED.is_global(), false);
    805    ///
    806    /// // Addresses reserved for private use (`10.0.0.0/8`, `172.16.0.0/12`, 192.168.0.0/16)
    807    /// assert_eq!(Ipv4Addr::new(10, 254, 0, 0).is_global(), false);
    808    /// assert_eq!(Ipv4Addr::new(192, 168, 10, 65).is_global(), false);
    809    /// assert_eq!(Ipv4Addr::new(172, 16, 10, 65).is_global(), false);
    810    ///
    811    /// // Addresses in the shared address space (`100.64.0.0/10`)
    812    /// assert_eq!(Ipv4Addr::new(100, 100, 0, 0).is_global(), false);
    813    ///
    814    /// // The loopback addresses (`127.0.0.0/8`)
    815    /// assert_eq!(Ipv4Addr::LOCALHOST.is_global(), false);
    816    ///
    817    /// // Link-local addresses (`169.254.0.0/16`)
    818    /// assert_eq!(Ipv4Addr::new(169, 254, 45, 1).is_global(), false);
    819    ///
    820    /// // Addresses reserved for documentation (`192.0.2.0/24`, `198.51.100.0/24`, `203.0.113.0/24`)
    821    /// assert_eq!(Ipv4Addr::new(192, 0, 2, 255).is_global(), false);
    822    /// assert_eq!(Ipv4Addr::new(198, 51, 100, 65).is_global(), false);
    823    /// assert_eq!(Ipv4Addr::new(203, 0, 113, 6).is_global(), false);
    824    ///
    825    /// // Addresses reserved for benchmarking (`198.18.0.0/15`)
    826    /// assert_eq!(Ipv4Addr::new(198, 18, 0, 0).is_global(), false);
    827    ///
    828    /// // Reserved addresses (`240.0.0.0/4`)
    829    /// assert_eq!(Ipv4Addr::new(250, 10, 20, 30).is_global(), false);
    830    ///
    831    /// // The broadcast address (`255.255.255.255`)
    832    /// assert_eq!(Ipv4Addr::BROADCAST.is_global(), false);
    833    ///
    834    /// // For a complete overview see the IANA IPv4 Special-Purpose Address Registry.
    835    /// ```
    836    #[unstable(feature = "ip", issue = "27709")]
    837    #[must_use]
    838    #[inline]
    839    pub const fn is_global(&self) -> bool {
    840        !(self.octets()[0] == 0 // "This network"
    841            || self.is_private()
    842            || self.is_shared()
    843            || self.is_loopback()
    844            || self.is_link_local()
    845            // addresses reserved for future protocols (`192.0.0.0/24`)
    846            // .9 and .10 are documented as globally reachable so they're excluded
    847            || (
    848                self.octets()[0] == 192 && self.octets()[1] == 0 && self.octets()[2] == 0
    849                && self.octets()[3] != 9 && self.octets()[3] != 10
    850            )
    851            || self.is_documentation()
    852            || self.is_benchmarking()
    853            || self.is_reserved()
    854            || self.is_broadcast())
    855    }
    856
    857    /// Returns [`true`] if this address is part of the Shared Address Space defined in
    858    /// [IETF RFC 6598] (`100.64.0.0/10`).
    859    ///
    860    /// [IETF RFC 6598]: https://tools.ietf.org/html/rfc6598
    861    ///
    862    /// # Examples
    863    ///
    864    /// ```
    865    /// #![feature(ip)]
    866    /// use std::net::Ipv4Addr;
    867    ///
    868    /// assert_eq!(Ipv4Addr::new(100, 64, 0, 0).is_shared(), true);
    869    /// assert_eq!(Ipv4Addr::new(100, 127, 255, 255).is_shared(), true);
    870    /// assert_eq!(Ipv4Addr::new(100, 128, 0, 0).is_shared(), false);
    871    /// ```
    872    #[unstable(feature = "ip", issue = "27709")]
    873    #[must_use]
    874    #[inline]
    875    pub const fn is_shared(&self) -> bool {
    876        self.octets()[0] == 100 && (self.octets()[1] & 0b1100_0000 == 0b0100_0000)
    877    }
    878
    879    /// Returns [`true`] if this address part of the `198.18.0.0/15` range, which is reserved for
    880    /// network devices benchmarking.
    881    ///
    882    /// This range is defined in [IETF RFC 2544] as `192.18.0.0` through
    883    /// `198.19.255.255` but [errata 423] corrects it to `198.18.0.0/15`.
    884    ///
    885    /// [IETF RFC 2544]: https://tools.ietf.org/html/rfc2544
    886    /// [errata 423]: https://www.rfc-editor.org/errata/eid423
    887    ///
    888    /// # Examples
    889    ///
    890    /// ```
    891    /// #![feature(ip)]
    892    /// use std::net::Ipv4Addr;
    893    ///
    894    /// assert_eq!(Ipv4Addr::new(198, 17, 255, 255).is_benchmarking(), false);
    895    /// assert_eq!(Ipv4Addr::new(198, 18, 0, 0).is_benchmarking(), true);
    896    /// assert_eq!(Ipv4Addr::new(198, 19, 255, 255).is_benchmarking(), true);
    897    /// assert_eq!(Ipv4Addr::new(198, 20, 0, 0).is_benchmarking(), false);
    898    /// ```
    899    #[unstable(feature = "ip", issue = "27709")]
    900    #[must_use]
    901    #[inline]
    902    pub const fn is_benchmarking(&self) -> bool {
    903        self.octets()[0] == 198 && (self.octets()[1] & 0xfe) == 18
    904    }
    905
    906    /// Returns [`true`] if this address is reserved by IANA for future use.
    907    ///
    908    /// [IETF RFC 1112] defines the block of reserved addresses as `240.0.0.0/4`.
    909    /// This range normally includes the broadcast address `255.255.255.255`, but
    910    /// this implementation explicitly excludes it, since it is obviously not
    911    /// reserved for future use.
    912    ///
    913    /// [IETF RFC 1112]: https://tools.ietf.org/html/rfc1112
    914    ///
    915    /// # Warning
    916    ///
    917    /// As IANA assigns new addresses, this method will be
    918    /// updated. This may result in non-reserved addresses being
    919    /// treated as reserved in code that relies on an outdated version
    920    /// of this method.
    921    ///
    922    /// # Examples
    923    ///
    924    /// ```
    925    /// #![feature(ip)]
    926    /// use std::net::Ipv4Addr;
    927    ///
    928    /// assert_eq!(Ipv4Addr::new(240, 0, 0, 0).is_reserved(), true);
    929    /// assert_eq!(Ipv4Addr::new(255, 255, 255, 254).is_reserved(), true);
    930    ///
    931    /// assert_eq!(Ipv4Addr::new(239, 255, 255, 255).is_reserved(), false);
    932    /// // The broadcast address is not considered as reserved for future use by this implementation
    933    /// assert_eq!(Ipv4Addr::new(255, 255, 255, 255).is_reserved(), false);
    934    /// ```
    935    #[unstable(feature = "ip", issue = "27709")]
    936    #[must_use]
    937    #[inline]
    938    pub const fn is_reserved(&self) -> bool {
    939        self.octets()[0] & 240 == 240 && !self.is_broadcast()
    940    }
    941
    942    /// Returns [`true`] if this is a multicast address (`224.0.0.0/4`).
    943    ///
    944    /// Multicast addresses have a most significant octet between `224` and `239`,
    945    /// and is defined by [IETF RFC 5771].
    946    ///
    947    /// [IETF RFC 5771]: https://tools.ietf.org/html/rfc5771
    948    ///
    949    /// # Examples
    950    ///
    951    /// ```
    952    /// use std::net::Ipv4Addr;
    953    ///
    954    /// assert_eq!(Ipv4Addr::new(224, 254, 0, 0).is_multicast(), true);
    955    /// assert_eq!(Ipv4Addr::new(236, 168, 10, 65).is_multicast(), true);
    956    /// assert_eq!(Ipv4Addr::new(172, 16, 10, 65).is_multicast(), false);
    957    /// ```
    958    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    959    #[stable(since = "1.7.0", feature = "ip_17")]
    960    #[must_use]
    961    #[inline]
    962    pub const fn is_multicast(&self) -> bool {
    963        self.octets()[0] >= 224 && self.octets()[0] <= 239
    964    }
    965
    966    /// Returns [`true`] if this is a broadcast address (`255.255.255.255`).
    967    ///
    968    /// A broadcast address has all octets set to `255` as defined in [IETF RFC 919].
    969    ///
    970    /// [IETF RFC 919]: https://tools.ietf.org/html/rfc919
    971    ///
    972    /// # Examples
    973    ///
    974    /// ```
    975    /// use std::net::Ipv4Addr;
    976    ///
    977    /// assert_eq!(Ipv4Addr::new(255, 255, 255, 255).is_broadcast(), true);
    978    /// assert_eq!(Ipv4Addr::new(236, 168, 10, 65).is_broadcast(), false);
    979    /// ```
    980    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    981    #[stable(since = "1.7.0", feature = "ip_17")]
    982    #[must_use]
    983    #[inline]
    984    pub const fn is_broadcast(&self) -> bool {
    985        u32::from_be_bytes(self.octets()) == u32::from_be_bytes(Self::BROADCAST.octets())
    986    }
    987
    988    /// Returns [`true`] if this address is in a range designated for documentation.
    989    ///
    990    /// This is defined in [IETF RFC 5737]:
    991    ///
    992    /// - `192.0.2.0/24` (TEST-NET-1)
    993    /// - `198.51.100.0/24` (TEST-NET-2)
    994    /// - `203.0.113.0/24` (TEST-NET-3)
    995    ///
    996    /// [IETF RFC 5737]: https://tools.ietf.org/html/rfc5737
    997    ///
    998    /// # Examples
    999    ///
    1000    /// ```
    1001    /// use std::net::Ipv4Addr;
    1002    ///
    1003    /// assert_eq!(Ipv4Addr::new(192, 0, 2, 255).is_documentation(), true);
    1004    /// assert_eq!(Ipv4Addr::new(198, 51, 100, 65).is_documentation(), true);
    1005    /// assert_eq!(Ipv4Addr::new(203, 0, 113, 6).is_documentation(), true);
    1006    /// assert_eq!(Ipv4Addr::new(193, 34, 17, 19).is_documentation(), false);
    1007    /// ```
    1008    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    1009    #[stable(since = "1.7.0", feature = "ip_17")]
    1010    #[must_use]
    1011    #[inline]
    1012    pub const fn is_documentation(&self) -> bool {
    1013        matches!(self.octets(), [192, 0, 2, _] | [198, 51, 100, _] | [203, 0, 113, _])
    1014    }
    1015
    1016    /// Converts this address to an [IPv4-compatible] [`IPv6` address].
    1017    ///
    1018    /// `a.b.c.d` becomes `::a.b.c.d`
    1019    ///
    1020    /// Note that IPv4-compatible addresses have been officially deprecated.
    1021    /// If you don't explicitly need an IPv4-compatible address for legacy reasons, consider using `to_ipv6_mapped` instead.
    1022    ///
    1023    /// [IPv4-compatible]: Ipv6Addr#ipv4-compatible-ipv6-addresses
    1024    /// [`IPv6` address]: Ipv6Addr
    1025    ///
    1026    /// # Examples
    1027    ///
    1028    /// ```
    1029    /// use std::net::{Ipv4Addr, Ipv6Addr};
    1030    ///
    1031    /// assert_eq!(
    1032    ///     Ipv4Addr::new(192, 0, 2, 255).to_ipv6_compatible(),
    1033    ///     Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0xc000, 0x2ff)
    1034    /// );
    1035    /// ```
    1036    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    1037    #[stable(feature = "rust1", since = "1.0.0")]
    1038    #[must_use = "this returns the result of the operation, \
    1039                  without modifying the original"]
    1040    #[inline]
    1041    pub const fn to_ipv6_compatible(&self) -> Ipv6Addr {
    1042        let [a, b, c, d] = self.octets();
    1043        Ipv6Addr { octets: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, a, b, c, d] }
    1044    }
    1045
    1046    /// Converts this address to an [IPv4-mapped] [`IPv6` address].
    1047    ///
    1048    /// `a.b.c.d` becomes `::ffff:a.b.c.d`
    1049    ///
    1050    /// [IPv4-mapped]: Ipv6Addr#ipv4-mapped-ipv6-addresses
    1051    /// [`IPv6` address]: Ipv6Addr
    1052    ///
    1053    /// # Examples
    1054    ///
    1055    /// ```
    1056    /// use std::net::{Ipv4Addr, Ipv6Addr};
    1057    ///
    1058    /// assert_eq!(Ipv4Addr::new(192, 0, 2, 255).to_ipv6_mapped(),
    1059    ///            Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc000, 0x2ff));
    1060    /// ```
    1061    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    1062    #[stable(feature = "rust1", since = "1.0.0")]
    1063    #[must_use = "this returns the result of the operation, \
    1064                  without modifying the original"]
    1065    #[inline]
    1066    pub const fn to_ipv6_mapped(&self) -> Ipv6Addr {
    1067        let [a, b, c, d] = self.octets();
    1068        Ipv6Addr { octets: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, a, b, c, d] }
    1069    }
    1070}
    1071
    1072#[stable(feature = "ip_addr", since = "1.7.0")]
    1073impl fmt::Display for IpAddr {
    1074    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
    1075        match self {
    1076            IpAddr::V4(ip) => ip.fmt(fmt),
    1077            IpAddr::V6(ip) => ip.fmt(fmt),
    1078        }
    1079    }
    1080}
    1081
    1082#[stable(feature = "ip_addr", since = "1.7.0")]
    1083impl fmt::Debug for IpAddr {
    1084    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
    1085        fmt::Display::fmt(self, fmt)
    1086    }
    1087}
    1088
    1089#[stable(feature = "ip_from_ip", since = "1.16.0")]
    1090#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    1091impl const From<Ipv4Addr> for IpAddr {
    1092    /// Copies this address to a new `IpAddr::V4`.
    1093    ///
    1094    /// # Examples
    1095    ///
    1096    /// ```
    1097    /// use std::net::{IpAddr, Ipv4Addr};
    1098    ///
    1099    /// let addr = Ipv4Addr::new(127, 0, 0, 1);
    1100    ///
    1101    /// assert_eq!(
    1102    ///     IpAddr::V4(addr),
    1103    ///     IpAddr::from(addr)
    1104    /// )
    1105    /// ```
    1106    #[inline]
    1107    fn from(ipv4: Ipv4Addr) -> IpAddr {
    1108        IpAddr::V4(ipv4)
    1109    }
    1110}
    1111
    1112#[stable(feature = "ip_from_ip", since = "1.16.0")]
    1113#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    1114impl const From<Ipv6Addr> for IpAddr {
    1115    /// Copies this address to a new `IpAddr::V6`.
    1116    ///
    1117    /// # Examples
    1118    ///
    1119    /// ```
    1120    /// use std::net::{IpAddr, Ipv6Addr};
    1121    ///
    1122    /// let addr = Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff);
    1123    ///
    1124    /// assert_eq!(
    1125    ///     IpAddr::V6(addr),
    1126    ///     IpAddr::from(addr)
    1127    /// );
    1128    /// ```
    1129    #[inline]
    1130    fn from(ipv6: Ipv6Addr) -> IpAddr {
    1131        IpAddr::V6(ipv6)
    1132    }
    1133}
    1134
    1135#[stable(feature = "rust1", since = "1.0.0")]
    1136impl fmt::Display for Ipv4Addr {
    1137    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
    1138        let octets = self.octets();
    1139
    1140        // If there are no alignment requirements, write the IP address directly to `f`.
    1141        // Otherwise, write it to a local buffer and then use `f.pad`.
    1142        if fmt.precision().is_none() && fmt.width().is_none() {
    1143            write!(fmt, "{}.{}.{}.{}", octets[0], octets[1], octets[2], octets[3])
    1144        } else {
    1145            const LONGEST_IPV4_ADDR: &str = "255.255.255.255";
    1146
    1147            let mut buf = DisplayBuffer::<{ LONGEST_IPV4_ADDR.len() }>::new();
    1148            // Buffer is long enough for the longest possible IPv4 address, so this should never fail.
    1149            write!(buf, "{}.{}.{}.{}", octets[0], octets[1], octets[2], octets[3]).unwrap();
    1150
    1151            fmt.pad(buf.as_str())
    1152        }
    1153    }
    1154}
    1155
    1156#[stable(feature = "rust1", since = "1.0.0")]
    1157impl fmt::Debug for Ipv4Addr {
    1158    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
    1159        fmt::Display::fmt(self, fmt)
    1160    }
    1161}
    1162
    1163#[stable(feature = "ip_cmp", since = "1.16.0")]
    1164impl PartialEq<Ipv4Addr> for IpAddr {
    1165    #[inline]
    1166    fn eq(&self, other: &Ipv4Addr) -> bool {
    1167        match self {
    1168            IpAddr::V4(v4) => v4 == other,
    1169            IpAddr::V6(_) => false,
    1170        }
    1171    }
    1172}
    1173
    1174#[stable(feature = "ip_cmp", since = "1.16.0")]
    1175impl PartialEq<IpAddr> for Ipv4Addr {
    1176    #[inline]
    1177    fn eq(&self, other: &IpAddr) -> bool {
    1178        match other {
    1179            IpAddr::V4(v4) => self == v4,
    1180            IpAddr::V6(_) => false,
    1181        }
    1182    }
    1183}
    1184
    1185#[stable(feature = "rust1", since = "1.0.0")]
    1186impl PartialOrd for Ipv4Addr {
    1187    #[inline]
    1188    fn partial_cmp(&self, other: &Ipv4Addr) -> Option<Ordering> {
    1189        Some(self.cmp(other))
    1190    }
    1191}
    1192
    1193#[stable(feature = "ip_cmp", since = "1.16.0")]
    1194impl PartialOrd<Ipv4Addr> for IpAddr {
    1195    #[inline]
    1196    fn partial_cmp(&self, other: &Ipv4Addr) -> Option<Ordering> {
    1197        match self {
    1198            IpAddr::V4(v4) => v4.partial_cmp(other),
    1199            IpAddr::V6(_) => Some(Ordering::Greater),
    1200        }
    1201    }
    1202}
    1203
    1204#[stable(feature = "ip_cmp", since = "1.16.0")]
    1205impl PartialOrd<IpAddr> for Ipv4Addr {
    1206    #[inline]
    1207    fn partial_cmp(&self, other: &IpAddr) -> Option<Ordering> {
    1208        match other {
    1209            IpAddr::V4(v4) => self.partial_cmp(v4),
    1210            IpAddr::V6(_) => Some(Ordering::Less),
    1211        }
    1212    }
    1213}
    1214
    1215#[stable(feature = "rust1", since = "1.0.0")]
    1216impl Ord for Ipv4Addr {
    1217    #[inline]
    1218    fn cmp(&self, other: &Ipv4Addr) -> Ordering {
    1219        self.octets.cmp(&other.octets)
    1220    }
    1221}
    1222
    1223#[stable(feature = "ip_u32", since = "1.1.0")]
    1224#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    1225impl const From<Ipv4Addr> for u32 {
    1226    /// Uses [`Ipv4Addr::to_bits`] to convert an IPv4 address to a host byte order `u32`.
    1227    #[inline]
    1228    fn from(ip: Ipv4Addr) -> u32 {
    1229        ip.to_bits()
    1230    }
    1231}
    1232
    1233#[stable(feature = "ip_u32", since = "1.1.0")]
    1234#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    1235impl const From<u32> for Ipv4Addr {
    1236    /// Uses [`Ipv4Addr::from_bits`] to convert a host byte order `u32` into an IPv4 address.
    1237    #[inline]
    1238    fn from(ip: u32) -> Ipv4Addr {
    1239        Ipv4Addr::from_bits(ip)
    1240    }
    1241}
    1242
    1243#[stable(feature = "from_slice_v4", since = "1.9.0")]
    1244#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    1245impl const From<[u8; 4]> for Ipv4Addr {
    1246    /// Creates an `Ipv4Addr` from a four element byte array.
    1247    ///
    1248    /// # Examples
    1249    ///
    1250    /// ```
    1251    /// use std::net::Ipv4Addr;
    1252    ///
    1253    /// let addr = Ipv4Addr::from([13u8, 12u8, 11u8, 10u8]);
    1254    /// assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);
    1255    /// ```
    1256    #[inline]
    1257    fn from(octets: [u8; 4]) -> Ipv4Addr {
    1258        Ipv4Addr { octets }
    1259    }
    1260}
    1261
    1262#[stable(feature = "ip_from_slice", since = "1.17.0")]
    1263#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    1264impl const From<[u8; 4]> for IpAddr {
    1265    /// Creates an `IpAddr::V4` from a four element byte array.
    1266    ///
    1267    /// # Examples
    1268    ///
    1269    /// ```
    1270    /// use std::net::{IpAddr, Ipv4Addr};
    1271    ///
    1272    /// let addr = IpAddr::from([13u8, 12u8, 11u8, 10u8]);
    1273    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(13, 12, 11, 10)), addr);
    1274    /// ```
    1275    #[inline]
    1276    fn from(octets: [u8; 4]) -> IpAddr {
    1277        IpAddr::V4(Ipv4Addr::from(octets))
    1278    }
    1279}
    1280
    1281impl Ipv6Addr {
    1282    /// Creates a new IPv6 address from eight 16-bit segments.
    1283    ///
    1284    /// The result will represent the IP address `a:b:c:d:e:f:g:h`.
    1285    ///
    1286    /// # Examples
    1287    ///
    1288    /// ```
    1289    /// use std::net::Ipv6Addr;
    1290    ///
    1291    /// let addr = Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff);
    1292    /// ```
    1293    #[rustc_const_stable(feature = "const_ip_32", since = "1.32.0")]
    1294    #[stable(feature = "rust1", since = "1.0.0")]
    1295    #[must_use]
    1296    #[inline]
    1297    pub const fn new(a: u16, b: u16, c: u16, d: u16, e: u16, f: u16, g: u16, h: u16) -> Ipv6Addr {
    1298        let addr16 = [
    1299            a.to_be(),
    1300            b.to_be(),
    1301            c.to_be(),
    1302            d.to_be(),
    1303            e.to_be(),
    1304            f.to_be(),
    1305            g.to_be(),
    1306            h.to_be(),
    1307        ];
    1308        Ipv6Addr {
    1309            // All elements in `addr16` are big endian.
    1310            // SAFETY: `[u16; 8]` is always safe to transmute to `[u8; 16]`.
    1311            octets: unsafe { transmute::<_, [u8; 16]>(addr16) },
    1312        }
    1313    }
    1314
    1315    /// The size of an IPv6 address in bits.
    1316    ///
    1317    /// # Examples
    1318    ///
    1319    /// ```
    1320    /// use std::net::Ipv6Addr;
    1321    ///
    1322    /// assert_eq!(Ipv6Addr::BITS, 128);
    1323    /// ```
    1324    #[stable(feature = "ip_bits", since = "1.80.0")]
    1325    pub const BITS: u32 = 128;
    1326
    1327    /// Converts an IPv6 address into a `u128` representation using native byte order.
    1328    ///
    1329    /// Although IPv6 addresses are big-endian, the `u128` value will use the target platform's
    1330    /// native byte order. That is, the `u128` value is an integer representation of the IPv6
    1331    /// address and not an integer interpretation of the IPv6 address's big-endian bitstring. This
    1332    /// means that the `u128` value masked with `0xffffffffffffffffffffffffffff0000_u128` will set
    1333    /// the last segment in the address to 0, regardless of the target platform's endianness.
    1334    ///
    1335    /// # Examples
    1336    ///
    1337    /// ```
    1338    /// use std::net::Ipv6Addr;
    1339    ///
    1340    /// let addr = Ipv6Addr::new(
    1341    ///     0x1020, 0x3040, 0x5060, 0x7080,
    1342    ///     0x90A0, 0xB0C0, 0xD0E0, 0xF00D,
    1343    /// );
    1344    /// assert_eq!(0x102030405060708090A0B0C0D0E0F00D_u128, addr.to_bits());
    1345    /// ```
    1346    ///
    1347    /// ```
    1348    /// use std::net::Ipv6Addr;
    1349    ///
    1350    /// let addr = Ipv6Addr::new(
    1351    ///     0x1020, 0x3040, 0x5060, 0x7080,
    1352    ///     0x90A0, 0xB0C0, 0xD0E0, 0xF00D,
    1353    /// );
    1354    /// let addr_bits = addr.to_bits() & 0xffffffffffffffffffffffffffff0000_u128;
    1355    /// assert_eq!(
    1356    ///     Ipv6Addr::new(
    1357    ///         0x1020, 0x3040, 0x5060, 0x7080,
    1358    ///         0x90A0, 0xB0C0, 0xD0E0, 0x0000,
    1359    ///     ),
    1360    ///     Ipv6Addr::from_bits(addr_bits));
    1361    ///
    1362    /// ```
    1363    #[rustc_const_stable(feature = "ip_bits", since = "1.80.0")]
    1364    #[stable(feature = "ip_bits", since = "1.80.0")]
    1365    #[must_use]
    1366    #[inline]
    1367    pub const fn to_bits(self) -> u128 {
    1368        u128::from_be_bytes(self.octets)
    1369    }
    1370
    1371    /// Converts a native byte order `u128` into an IPv6 address.
    1372    ///
    1373    /// See [`Ipv6Addr::to_bits`] for an explanation on endianness.
    1374    ///
    1375    /// # Examples
    1376    ///
    1377    /// ```
    1378    /// use std::net::Ipv6Addr;
    1379    ///
    1380    /// let addr = Ipv6Addr::from_bits(0x102030405060708090A0B0C0D0E0F00D_u128);
    1381    /// assert_eq!(
    1382    ///     Ipv6Addr::new(
    1383    ///         0x1020, 0x3040, 0x5060, 0x7080,
    1384    ///         0x90A0, 0xB0C0, 0xD0E0, 0xF00D,
    1385    ///     ),
    1386    ///     addr);
    1387    /// ```
    1388    #[rustc_const_stable(feature = "ip_bits", since = "1.80.0")]
    1389    #[stable(feature = "ip_bits", since = "1.80.0")]
    1390    #[must_use]
    1391    #[inline]
    1392    pub const fn from_bits(bits: u128) -> Ipv6Addr {
    1393        Ipv6Addr { octets: bits.to_be_bytes() }
    1394    }
    1395
    1396    /// An IPv6 address representing localhost: `::1`.
    1397    ///
    1398    /// This corresponds to constant `IN6ADDR_LOOPBACK_INIT` or `in6addr_loopback` in other
    1399    /// languages.
    1400    ///
    1401    /// # Examples
    1402    ///
    1403    /// ```
    1404    /// use std::net::Ipv6Addr;
    1405    ///
    1406    /// let addr = Ipv6Addr::LOCALHOST;
    1407    /// assert_eq!(addr, Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1));
    1408    /// ```
    1409    #[doc(alias = "IN6ADDR_LOOPBACK_INIT")]
    1410    #[doc(alias = "in6addr_loopback")]
    1411    #[stable(feature = "ip_constructors", since = "1.30.0")]
    1412    pub const LOCALHOST: Self = Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1);
    1413
    1414    /// An IPv6 address representing the unspecified address: `::`.
    1415    ///
    1416    /// This corresponds to constant `IN6ADDR_ANY_INIT` or `in6addr_any` in other languages.
    1417    ///
    1418    /// # Examples
    1419    ///
    1420    /// ```
    1421    /// use std::net::Ipv6Addr;
    1422    ///
    1423    /// let addr = Ipv6Addr::UNSPECIFIED;
    1424    /// assert_eq!(addr, Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0));
    1425    /// ```
    1426    #[doc(alias = "IN6ADDR_ANY_INIT")]
    1427    #[doc(alias = "in6addr_any")]
    1428    #[stable(feature = "ip_constructors", since = "1.30.0")]
    1429    pub const UNSPECIFIED: Self = Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0);
    1430
    1431    /// Returns the eight 16-bit segments that make up this address.
    1432    ///
    1433    /// # Examples
    1434    ///
    1435    /// ```
    1436    /// use std::net::Ipv6Addr;
    1437    ///
    1438    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).segments(),
    1439    ///            [0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff]);
    1440    /// ```
    1441    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    1442    #[stable(feature = "rust1", since = "1.0.0")]
    1443    #[must_use]
    1444    #[inline]
    1445    pub const fn segments(&self) -> [u16; 8] {
    1446        // All elements in `self.octets` must be big endian.
    1447        // SAFETY: `[u8; 16]` is always safe to transmute to `[u16; 8]`.
    1448        let [a, b, c, d, e, f, g, h] = unsafe { transmute::<_, [u16; 8]>(self.octets) };
    1449        // We want native endian u16
    1450        [
    1451            u16::from_be(a),
    1452            u16::from_be(b),
    1453            u16::from_be(c),
    1454            u16::from_be(d),
    1455            u16::from_be(e),
    1456            u16::from_be(f),
    1457            u16::from_be(g),
    1458            u16::from_be(h),
    1459        ]
    1460    }
    1461
    1462    /// Creates an `Ipv6Addr` from an eight element 16-bit array.
    1463    ///
    1464    /// # Examples
    1465    ///
    1466    /// ```
    1467    /// use std::net::Ipv6Addr;
    1468    ///
    1469    /// let addr = Ipv6Addr::from_segments([
    1470    ///     0x20du16, 0x20cu16, 0x20bu16, 0x20au16,
    1471    ///     0x209u16, 0x208u16, 0x207u16, 0x206u16,
    1472    /// ]);
    1473    /// assert_eq!(
    1474    ///     Ipv6Addr::new(
    1475    ///         0x20d, 0x20c, 0x20b, 0x20a,
    1476    ///         0x209, 0x208, 0x207, 0x206,
    1477    ///     ),
    1478    ///     addr
    1479    /// );
    1480    /// ```
    1481    #[stable(feature = "ip_from", since = "1.91.0")]
    1482    #[rustc_const_stable(feature = "ip_from", since = "1.91.0")]
    1483    #[must_use]
    1484    #[inline]
    1485    pub const fn from_segments(segments: [u16; 8]) -> Ipv6Addr {
    1486        let [a, b, c, d, e, f, g, h] = segments;
    1487        Ipv6Addr::new(a, b, c, d, e, f, g, h)
    1488    }
    1489
    1490    /// Returns [`true`] for the special 'unspecified' address (`::`).
    1491    ///
    1492    /// This property is defined in [IETF RFC 4291].
    1493    ///
    1494    /// [IETF RFC 4291]: https://tools.ietf.org/html/rfc4291
    1495    ///
    1496    /// # Examples
    1497    ///
    1498    /// ```
    1499    /// use std::net::Ipv6Addr;
    1500    ///
    1501    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).is_unspecified(), false);
    1502    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0).is_unspecified(), true);
    1503    /// ```
    1504    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    1505    #[stable(since = "1.7.0", feature = "ip_17")]
    1506    #[must_use]
    1507    #[inline]
    1508    pub const fn is_unspecified(&self) -> bool {
    1509        u128::from_be_bytes(self.octets()) == u128::from_be_bytes(Ipv6Addr::UNSPECIFIED.octets())
    1510    }
    1511
    1512    /// Returns [`true`] if this is the [loopback address] (`::1`),
    1513    /// as defined in [IETF RFC 4291 section 2.5.3].
    1514    ///
    1515    /// Contrary to IPv4, in IPv6 there is only one loopback address.
    1516    ///
    1517    /// [loopback address]: Ipv6Addr::LOCALHOST
    1518    /// [IETF RFC 4291 section 2.5.3]: https://tools.ietf.org/html/rfc4291#section-2.5.3
    1519    ///
    1520    /// # Examples
    1521    ///
    1522    /// ```
    1523    /// use std::net::Ipv6Addr;
    1524    ///
    1525    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).is_loopback(), false);
    1526    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0x1).is_loopback(), true);
    1527    /// ```
    1528    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    1529    #[stable(since = "1.7.0", feature = "ip_17")]
    1530    #[must_use]
    1531    #[inline]
    1532    pub const fn is_loopback(&self) -> bool {
    1533        u128::from_be_bytes(self.octets()) == u128::from_be_bytes(Ipv6Addr::LOCALHOST.octets())
    1534    }
    1535
    1536    /// Returns [`true`] if the address appears to be globally reachable
    1537    /// as specified by the [IANA IPv6 Special-Purpose Address Registry].
    1538    ///
    1539    /// Whether or not an address is practically reachable will depend on your
    1540    /// network configuration. Most IPv6 addresses are globally reachable, unless
    1541    /// they are specifically defined as *not* globally reachable.
    1542    ///
    1543    /// Non-exhaustive list of notable addresses that are not globally reachable:
    1544    /// - The [unspecified address] ([`is_unspecified`](Ipv6Addr::is_unspecified))
    1545    /// - The [loopback address] ([`is_loopback`](Ipv6Addr::is_loopback))
    1546    /// - IPv4-mapped addresses
    1547    /// - Addresses reserved for benchmarking ([`is_benchmarking`](Ipv6Addr::is_benchmarking))
    1548    /// - Addresses reserved for documentation ([`is_documentation`](Ipv6Addr::is_documentation))
    1549    /// - Unique local addresses ([`is_unique_local`](Ipv6Addr::is_unique_local))
    1550    /// - Unicast addresses with link-local scope ([`is_unicast_link_local`](Ipv6Addr::is_unicast_link_local))
    1551    ///
    1552    /// For the complete overview of which addresses are globally reachable, see the table at the [IANA IPv6 Special-Purpose Address Registry].
    1553    ///
    1554    /// Note that an address having global scope is not the same as being globally reachable,
    1555    /// and there is no direct relation between the two concepts: There exist addresses with global scope
    1556    /// that are not globally reachable (for example unique local addresses),
    1557    /// and addresses that are globally reachable without having global scope
    1558    /// (multicast addresses with non-global scope).
    1559    ///
    1560    /// [IANA IPv6 Special-Purpose Address Registry]: https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml
    1561    /// [unspecified address]: Ipv6Addr::UNSPECIFIED
    1562    /// [loopback address]: Ipv6Addr::LOCALHOST
    1563    ///
    1564    /// # Examples
    1565    ///
    1566    /// ```
    1567    /// #![feature(ip)]
    1568    ///
    1569    /// use std::net::Ipv6Addr;
    1570    ///
    1571    /// // Most IPv6 addresses are globally reachable:
    1572    /// assert_eq!(Ipv6Addr::new(0x26, 0, 0x1c9, 0, 0, 0xafc8, 0x10, 0x1).is_global(), true);
    1573    ///
    1574    /// // However some addresses have been assigned a special meaning
    1575    /// // that makes them not globally reachable. Some examples are:
    1576    ///
    1577    /// // The unspecified address (`::`)
    1578    /// assert_eq!(Ipv6Addr::UNSPECIFIED.is_global(), false);
    1579    ///
    1580    /// // The loopback address (`::1`)
    1581    /// assert_eq!(Ipv6Addr::LOCALHOST.is_global(), false);
    1582    ///
    1583    /// // IPv4-mapped addresses (`::ffff:0:0/96`)
    1584    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).is_global(), false);
    1585    ///
    1586    /// // Addresses reserved for benchmarking (`2001:2::/48`)
    1587    /// assert_eq!(Ipv6Addr::new(0x2001, 2, 0, 0, 0, 0, 0, 1,).is_global(), false);
    1588    ///
    1589    /// // Addresses reserved for documentation (`2001:db8::/32` and `3fff::/20`)
    1590    /// assert_eq!(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 1).is_global(), false);
    1591    /// assert_eq!(Ipv6Addr::new(0x3fff, 0, 0, 0, 0, 0, 0, 0).is_global(), false);
    1592    ///
    1593    /// // Unique local addresses (`fc00::/7`)
    1594    /// assert_eq!(Ipv6Addr::new(0xfc02, 0, 0, 0, 0, 0, 0, 1).is_global(), false);
    1595    ///
    1596    /// // Unicast addresses with link-local scope (`fe80::/10`)
    1597    /// assert_eq!(Ipv6Addr::new(0xfe81, 0, 0, 0, 0, 0, 0, 1).is_global(), false);
    1598    ///
    1599    /// // For a complete overview see the IANA IPv6 Special-Purpose Address Registry.
    1600    /// ```
    1601    #[unstable(feature = "ip", issue = "27709")]
    1602    #[must_use]
    1603    #[inline]
    1604    pub const fn is_global(&self) -> bool {
    1605        !(self.is_unspecified()
    1606            || self.is_loopback()
    1607            // IPv4-mapped Address (`::ffff:0:0/96`)
    1608            || matches!(self.segments(), [0, 0, 0, 0, 0, 0xffff, _, _])
    1609            // IPv4-IPv6 Translat. (`64:ff9b:1::/48`)
    1610            || matches!(self.segments(), [0x64, 0xff9b, 1, _, _, _, _, _])
    1611            // Discard-Only Address Block (`100::/64`)
    1612            || matches!(self.segments(), [0x100, 0, 0, 0, _, _, _, _])
    1613            // IETF Protocol Assignments (`2001::/23`)
    1614            || (matches!(self.segments(), [0x2001, b, _, _, _, _, _, _] if b < 0x200)
    1615                && !(
    1616                    // Port Control Protocol Anycast (`2001:1::1`)
    1617                    u128::from_be_bytes(self.octets()) == 0x2001_0001_0000_0000_0000_0000_0000_0001
    1618                    // Traversal Using Relays around NAT Anycast (`2001:1::2`)
    1619                    || u128::from_be_bytes(self.octets()) == 0x2001_0001_0000_0000_0000_0000_0000_0002
    1620                    // AMT (`2001:3::/32`)
    1621                    || matches!(self.segments(), [0x2001, 3, _, _, _, _, _, _])
    1622                    // AS112-v6 (`2001:4:112::/48`)
    1623                    || matches!(self.segments(), [0x2001, 4, 0x112, _, _, _, _, _])
    1624                    // ORCHIDv2 (`2001:20::/28`)
    1625                    // Drone Remote ID Protocol Entity Tags (DETs) Prefix (`2001:30::/28`)`
    1626                    || matches!(self.segments(), [0x2001, b, _, _, _, _, _, _] if b >= 0x20 && b <= 0x3F)
    1627                ))
    1628            // 6to4 (`2002::/16`) – it's not explicitly documented as globally reachable,
    1629            // IANA says N/A.
    1630            || matches!(self.segments(), [0x2002, _, _, _, _, _, _, _])
    1631            || self.is_documentation()
    1632            // Segment Routing (SRv6) SIDs (`5f00::/16`)
    1633            || matches!(self.segments(), [0x5f00, ..])
    1634            || self.is_unique_local()
    1635            || self.is_unicast_link_local())
    1636    }
    1637
    1638    /// Returns [`true`] if this is a unique local address (`fc00::/7`).
    1639    ///
    1640    /// This property is defined in [IETF RFC 4193].
    1641    ///
    1642    /// [IETF RFC 4193]: https://tools.ietf.org/html/rfc4193
    1643    ///
    1644    /// # Examples
    1645    ///
    1646    /// ```
    1647    /// use std::net::Ipv6Addr;
    1648    ///
    1649    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).is_unique_local(), false);
    1650    /// assert_eq!(Ipv6Addr::new(0xfc02, 0, 0, 0, 0, 0, 0, 0).is_unique_local(), true);
    1651    /// ```
    1652    #[must_use]
    1653    #[inline]
    1654    #[stable(feature = "ipv6_is_unique_local", since = "1.84.0")]
    1655    #[rustc_const_stable(feature = "ipv6_is_unique_local", since = "1.84.0")]
    1656    pub const fn is_unique_local(&self) -> bool {
    1657        (self.segments()[0] & 0xfe00) == 0xfc00
    1658    }
    1659
    1660    /// Returns [`true`] if this is a unicast address, as defined by [IETF RFC 4291].
    1661    /// Any address that is not a [multicast address] (`ff00::/8`) is unicast.
    1662    ///
    1663    /// [IETF RFC 4291]: https://tools.ietf.org/html/rfc4291
    1664    /// [multicast address]: Ipv6Addr::is_multicast
    1665    ///
    1666    /// # Examples
    1667    ///
    1668    /// ```
    1669    /// #![feature(ip)]
    1670    ///
    1671    /// use std::net::Ipv6Addr;
    1672    ///
    1673    /// // The unspecified and loopback addresses are unicast.
    1674    /// assert_eq!(Ipv6Addr::UNSPECIFIED.is_unicast(), true);
    1675    /// assert_eq!(Ipv6Addr::LOCALHOST.is_unicast(), true);
    1676    ///
    1677    /// // Any address that is not a multicast address (`ff00::/8`) is unicast.
    1678    /// assert_eq!(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0).is_unicast(), true);
    1679    /// assert_eq!(Ipv6Addr::new(0xff00, 0, 0, 0, 0, 0, 0, 0).is_unicast(), false);
    1680    /// ```
    1681    #[unstable(feature = "ip", issue = "27709")]
    1682    #[must_use]
    1683    #[inline]
    1684    pub const fn is_unicast(&self) -> bool {
    1685        !self.is_multicast()
    1686    }
    1687
    1688    /// Returns `true` if the address is a unicast address with link-local scope,
    1689    /// as defined in [RFC 4291].
    1690    ///
    1691    /// A unicast address has link-local scope if it has the prefix `fe80::/10`, as per [RFC 4291 section 2.4].
    1692    /// Note that this encompasses more addresses than those defined in [RFC 4291 section 2.5.6],
    1693    /// which describes "Link-Local IPv6 Unicast Addresses" as having the following stricter format:
    1694    ///
    1695    /// ```text
    1696    /// | 10 bits  |         54 bits         |          64 bits           |
    1697    /// +----------+-------------------------+----------------------------+
    1698    /// |1111111010|           0             |       interface ID         |
    1699    /// +----------+-------------------------+----------------------------+
    1700    /// ```
    1701    /// So while currently the only addresses with link-local scope an application will encounter are all in `fe80::/64`,
    1702    /// this might change in the future with the publication of new standards. More addresses in `fe80::/10` could be allocated,
    1703    /// and those addresses will have link-local scope.
    1704    ///
    1705    /// Also note that while [RFC 4291 section 2.5.3] mentions about the [loopback address] (`::1`) that "it is treated as having Link-Local scope",
    1706    /// this does not mean that the loopback address actually has link-local scope and this method will return `false` on it.
    1707    ///
    1708    /// [RFC 4291]: https://tools.ietf.org/html/rfc4291
    1709    /// [RFC 4291 section 2.4]: https://tools.ietf.org/html/rfc4291#section-2.4
    1710    /// [RFC 4291 section 2.5.3]: https://tools.ietf.org/html/rfc4291#section-2.5.3
    1711    /// [RFC 4291 section 2.5.6]: https://tools.ietf.org/html/rfc4291#section-2.5.6
    1712    /// [loopback address]: Ipv6Addr::LOCALHOST
    1713    ///
    1714    /// # Examples
    1715    ///
    1716    /// ```
    1717    /// use std::net::Ipv6Addr;
    1718    ///
    1719    /// // The loopback address (`::1`) does not actually have link-local scope.
    1720    /// assert_eq!(Ipv6Addr::LOCALHOST.is_unicast_link_local(), false);
    1721    ///
    1722    /// // Only addresses in `fe80::/10` have link-local scope.
    1723    /// assert_eq!(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0).is_unicast_link_local(), false);
    1724    /// assert_eq!(Ipv6Addr::new(0xfe80, 0, 0, 0, 0, 0, 0, 0).is_unicast_link_local(), true);
    1725    ///
    1726    /// // Addresses outside the stricter `fe80::/64` also have link-local scope.
    1727    /// assert_eq!(Ipv6Addr::new(0xfe80, 0, 0, 1, 0, 0, 0, 0).is_unicast_link_local(), true);
    1728    /// assert_eq!(Ipv6Addr::new(0xfe81, 0, 0, 0, 0, 0, 0, 0).is_unicast_link_local(), true);
    1729    /// ```
    1730    #[must_use]
    1731    #[inline]
    1732    #[stable(feature = "ipv6_is_unique_local", since = "1.84.0")]
    1733    #[rustc_const_stable(feature = "ipv6_is_unique_local", since = "1.84.0")]
    1734    pub const fn is_unicast_link_local(&self) -> bool {
    1735        (self.segments()[0] & 0xffc0) == 0xfe80
    1736    }
    1737
    1738    /// Returns [`true`] if this is an address reserved for documentation
    1739    /// (`2001:db8::/32` and `3fff::/20`).
    1740    ///
    1741    /// This property is defined by [IETF RFC 3849] and [IETF RFC 9637].
    1742    ///
    1743    /// [IETF RFC 3849]: https://tools.ietf.org/html/rfc3849
    1744    /// [IETF RFC 9637]: https://tools.ietf.org/html/rfc9637
    1745    ///
    1746    /// # Examples
    1747    ///
    1748    /// ```
    1749    /// #![feature(ip)]
    1750    ///
    1751    /// use std::net::Ipv6Addr;
    1752    ///
    1753    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).is_documentation(), false);
    1754    /// assert_eq!(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0).is_documentation(), true);
    1755    /// assert_eq!(Ipv6Addr::new(0x3fff, 0, 0, 0, 0, 0, 0, 0).is_documentation(), true);
    1756    /// ```
    1757    #[unstable(feature = "ip", issue = "27709")]
    1758    #[must_use]
    1759    #[inline]
    1760    pub const fn is_documentation(&self) -> bool {
    1761        matches!(self.segments(), [0x2001, 0xdb8, ..] | [0x3fff, 0..=0x0fff, ..])
    1762    }
    1763
    1764    /// Returns [`true`] if this is an address reserved for benchmarking (`2001:2::/48`).
    1765    ///
    1766    /// This property is defined in [IETF RFC 5180], where it is mistakenly specified as covering the range `2001:0200::/48`.
    1767    /// This is corrected in [IETF RFC Errata 1752] to `2001:0002::/48`.
    1768    ///
    1769    /// [IETF RFC 5180]: https://tools.ietf.org/html/rfc5180
    1770    /// [IETF RFC Errata 1752]: https://www.rfc-editor.org/errata_search.php?eid=1752
    1771    ///
    1772    /// ```
    1773    /// #![feature(ip)]
    1774    ///
    1775    /// use std::net::Ipv6Addr;
    1776    ///
    1777    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc613, 0x0).is_benchmarking(), false);
    1778    /// assert_eq!(Ipv6Addr::new(0x2001, 0x2, 0, 0, 0, 0, 0, 0).is_benchmarking(), true);
    1779    /// ```
    1780    #[unstable(feature = "ip", issue = "27709")]
    1781    #[must_use]
    1782    #[inline]
    1783    pub const fn is_benchmarking(&self) -> bool {
    1784        (self.segments()[0] == 0x2001) && (self.segments()[1] == 0x2) && (self.segments()[2] == 0)
    1785    }
    1786
    1787    /// Returns [`true`] if the address is a globally routable unicast address.
    1788    ///
    1789    /// The following return false:
    1790    ///
    1791    /// - the loopback address
    1792    /// - the link-local addresses
    1793    /// - unique local addresses
    1794    /// - the unspecified address
    1795    /// - the address range reserved for documentation
    1796    ///
    1797    /// This method returns [`true`] for site-local addresses as per [RFC 4291 section 2.5.7]
    1798    ///
    1799    /// ```no_rust
    1800    /// The special behavior of [the site-local unicast] prefix defined in [RFC3513] must no longer
    1801    /// be supported in new implementations (i.e., new implementations must treat this prefix as
    1802    /// Global Unicast).
    1803    /// ```
    1804    ///
    1805    /// [RFC 4291 section 2.5.7]: https://tools.ietf.org/html/rfc4291#section-2.5.7
    1806    ///
    1807    /// # Examples
    1808    ///
    1809    /// ```
    1810    /// #![feature(ip)]
    1811    ///
    1812    /// use std::net::Ipv6Addr;
    1813    ///
    1814    /// assert_eq!(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0).is_unicast_global(), false);
    1815    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).is_unicast_global(), true);
    1816    /// ```
    1817    #[unstable(feature = "ip", issue = "27709")]
    1818    #[must_use]
    1819    #[inline]
    1820    pub const fn is_unicast_global(&self) -> bool {
    1821        self.is_unicast()
    1822            && !self.is_loopback()
    1823            && !self.is_unicast_link_local()
    1824            && !self.is_unique_local()
    1825            && !self.is_unspecified()
    1826            && !self.is_documentation()
    1827            && !self.is_benchmarking()
    1828    }
    1829
    1830    /// Returns the address's multicast scope if the address is multicast.
    1831    ///
    1832    /// # Examples
    1833    ///
    1834    /// ```
    1835    /// #![feature(ip)]
    1836    ///
    1837    /// use std::net::{Ipv6Addr, Ipv6MulticastScope};
    1838    ///
    1839    /// assert_eq!(
    1840    ///     Ipv6Addr::new(0xff0e, 0, 0, 0, 0, 0, 0, 0).multicast_scope(),
    1841    ///     Some(Ipv6MulticastScope::Global)
    1842    /// );
    1843    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).multicast_scope(), None);
    1844    /// ```
    1845    #[unstable(feature = "ip", issue = "27709")]
    1846    #[must_use]
    1847    #[inline]
    1848    pub const fn multicast_scope(&self) -> Option<Ipv6MulticastScope> {
    1849        if self.is_multicast() {
    1850            match self.segments()[0] & 0x000f {
    1851                1 => Some(Ipv6MulticastScope::InterfaceLocal),
    1852                2 => Some(Ipv6MulticastScope::LinkLocal),
    1853                3 => Some(Ipv6MulticastScope::RealmLocal),
    1854                4 => Some(Ipv6MulticastScope::AdminLocal),
    1855                5 => Some(Ipv6MulticastScope::SiteLocal),
    1856                8 => Some(Ipv6MulticastScope::OrganizationLocal),
    1857                14 => Some(Ipv6MulticastScope::Global),
    1858                _ => None,
    1859            }
    1860        } else {
    1861            None
    1862        }
    1863    }
    1864
    1865    /// Returns [`true`] if this is a multicast address (`ff00::/8`).
    1866    ///
    1867    /// This property is defined by [IETF RFC 4291].
    1868    ///
    1869    /// [IETF RFC 4291]: https://tools.ietf.org/html/rfc4291
    1870    ///
    1871    /// # Examples
    1872    ///
    1873    /// ```
    1874    /// use std::net::Ipv6Addr;
    1875    ///
    1876    /// assert_eq!(Ipv6Addr::new(0xff00, 0, 0, 0, 0, 0, 0, 0).is_multicast(), true);
    1877    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).is_multicast(), false);
    1878    /// ```
    1879    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    1880    #[stable(since = "1.7.0", feature = "ip_17")]
    1881    #[must_use]
    1882    #[inline]
    1883    pub const fn is_multicast(&self) -> bool {
    1884        (self.segments()[0] & 0xff00) == 0xff00
    1885    }
    1886
    1887    /// Returns [`true`] if the address is an IPv4-mapped address (`::ffff:0:0/96`).
    1888    ///
    1889    /// IPv4-mapped addresses can be converted to their canonical IPv4 address with
    1890    /// [`to_ipv4_mapped`](Ipv6Addr::to_ipv4_mapped).
    1891    ///
    1892    /// # Examples
    1893    /// ```
    1894    /// #![feature(ip)]
    1895    ///
    1896    /// use std::net::{Ipv4Addr, Ipv6Addr};
    1897    ///
    1898    /// let ipv4_mapped = Ipv4Addr::new(192, 0, 2, 255).to_ipv6_mapped();
    1899    /// assert_eq!(ipv4_mapped.is_ipv4_mapped(), true);
    1900    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc000, 0x2ff).is_ipv4_mapped(), true);
    1901    ///
    1902    /// assert_eq!(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0).is_ipv4_mapped(), false);
    1903    /// ```
    1904    #[unstable(feature = "ip", issue = "27709")]
    1905    #[must_use]
    1906    #[inline]
    1907    pub const fn is_ipv4_mapped(&self) -> bool {
    1908        matches!(self.segments(), [0, 0, 0, 0, 0, 0xffff, _, _])
    1909    }
    1910
    1911    /// Converts this address to an [`IPv4` address] if it's an [IPv4-mapped] address,
    1912    /// as defined in [IETF RFC 4291 section 2.5.5.2], otherwise returns [`None`].
    1913    ///
    1914    /// `::ffff:a.b.c.d` becomes `a.b.c.d`.
    1915    /// All addresses *not* starting with `::ffff` will return `None`.
    1916    ///
    1917    /// [`IPv4` address]: Ipv4Addr
    1918    /// [IPv4-mapped]: Ipv6Addr
    1919    /// [IETF RFC 4291 section 2.5.5.2]: https://tools.ietf.org/html/rfc4291#section-2.5.5.2
    1920    ///
    1921    /// # Examples
    1922    ///
    1923    /// ```
    1924    /// use std::net::{Ipv4Addr, Ipv6Addr};
    1925    ///
    1926    /// assert_eq!(Ipv6Addr::new(0xff00, 0, 0, 0, 0, 0, 0, 0).to_ipv4_mapped(), None);
    1927    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).to_ipv4_mapped(),
    1928    ///            Some(Ipv4Addr::new(192, 10, 2, 255)));
    1929    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1).to_ipv4_mapped(), None);
    1930    /// ```
    1931    #[inline]
    1932    #[must_use = "this returns the result of the operation, \
    1933                  without modifying the original"]
    1934    #[stable(feature = "ipv6_to_ipv4_mapped", since = "1.63.0")]
    1935    #[rustc_const_stable(feature = "const_ipv6_to_ipv4_mapped", since = "1.75.0")]
    1936    pub const fn to_ipv4_mapped(&self) -> Option<Ipv4Addr> {
    1937        match self.octets() {
    1938            [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, a, b, c, d] => {
    1939                Some(Ipv4Addr::new(a, b, c, d))
    1940            }
    1941            _ => None,
    1942        }
    1943    }
    1944
    1945    /// Converts this address to an [`IPv4` address] if it is either
    1946    /// an [IPv4-compatible] address as defined in [IETF RFC 4291 section 2.5.5.1],
    1947    /// or an [IPv4-mapped] address as defined in [IETF RFC 4291 section 2.5.5.2],
    1948    /// otherwise returns [`None`].
    1949    ///
    1950    /// Note that this will return an [`IPv4` address] for the IPv6 loopback address `::1`. Use
    1951    /// [`Ipv6Addr::to_ipv4_mapped`] to avoid this.
    1952    ///
    1953    /// `::a.b.c.d` and `::ffff:a.b.c.d` become `a.b.c.d`. `::1` becomes `0.0.0.1`.
    1954    /// All addresses *not* starting with either all zeroes or `::ffff` will return `None`.
    1955    ///
    1956    /// [`IPv4` address]: Ipv4Addr
    1957    /// [IPv4-compatible]: Ipv6Addr#ipv4-compatible-ipv6-addresses
    1958    /// [IPv4-mapped]: Ipv6Addr#ipv4-mapped-ipv6-addresses
    1959    /// [IETF RFC 4291 section 2.5.5.1]: https://tools.ietf.org/html/rfc4291#section-2.5.5.1
    1960    /// [IETF RFC 4291 section 2.5.5.2]: https://tools.ietf.org/html/rfc4291#section-2.5.5.2
    1961    ///
    1962    /// # Examples
    1963    ///
    1964    /// ```
    1965    /// use std::net::{Ipv4Addr, Ipv6Addr};
    1966    ///
    1967    /// assert_eq!(Ipv6Addr::new(0xff00, 0, 0, 0, 0, 0, 0, 0).to_ipv4(), None);
    1968    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).to_ipv4(),
    1969    ///            Some(Ipv4Addr::new(192, 10, 2, 255)));
    1970    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1).to_ipv4(),
    1971    ///            Some(Ipv4Addr::new(0, 0, 0, 1)));
    1972    /// ```
    1973    #[rustc_const_stable(feature = "const_ip_50", since = "1.50.0")]
    1974    #[stable(feature = "rust1", since = "1.0.0")]
    1975    #[must_use = "this returns the result of the operation, \
    1976                  without modifying the original"]
    1977    #[inline]
    1978    pub const fn to_ipv4(&self) -> Option<Ipv4Addr> {
    1979        if let [0, 0, 0, 0, 0, 0 | 0xffff, ab, cd] = self.segments() {
    1980            let [a, b] = ab.to_be_bytes();
    1981            let [c, d] = cd.to_be_bytes();
    1982            Some(Ipv4Addr::new(a, b, c, d))
    1983        } else {
    1984            None
    1985        }
    1986    }
    1987
    1988    /// Converts this address to an `IpAddr::V4` if it is an IPv4-mapped address,
    1989    /// otherwise returns self wrapped in an `IpAddr::V6`.
    1990    ///
    1991    /// # Examples
    1992    ///
    1993    /// ```
    1994    /// use std::net::Ipv6Addr;
    1995    ///
    1996    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0x7f00, 0x1).is_loopback(), false);
    1997    /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0x7f00, 0x1).to_canonical().is_loopback(), true);
    1998    /// ```
    1999    #[inline]
    2000    #[must_use = "this returns the result of the operation, \
    2001                  without modifying the original"]
    2002    #[stable(feature = "ip_to_canonical", since = "1.75.0")]
    2003    #[rustc_const_stable(feature = "ip_to_canonical", since = "1.75.0")]
    2004    pub const fn to_canonical(&self) -> IpAddr {
    2005        if let Some(mapped) = self.to_ipv4_mapped() {
    2006            return IpAddr::V4(mapped);
    2007        }
    2008        IpAddr::V6(*self)
    2009    }
    2010
    2011    /// Returns the sixteen eight-bit integers the IPv6 address consists of.
    2012    ///
    2013    /// ```
    2014    /// use std::net::Ipv6Addr;
    2015    ///
    2016    /// assert_eq!(Ipv6Addr::new(0xff00, 0, 0, 0, 0, 0, 0, 0).octets(),
    2017    ///            [0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]);
    2018    /// ```
    2019    #[rustc_const_stable(feature = "const_ip_32", since = "1.32.0")]
    2020    #[stable(feature = "ipv6_to_octets", since = "1.12.0")]
    2021    #[must_use]
    2022    #[inline]
    2023    pub const fn octets(&self) -> [u8; 16] {
    2024        self.octets
    2025    }
    2026
    2027    /// Creates an `Ipv6Addr` from a sixteen element byte array.
    2028    ///
    2029    /// # Examples
    2030    ///
    2031    /// ```
    2032    /// use std::net::Ipv6Addr;
    2033    ///
    2034    /// let addr = Ipv6Addr::from_octets([
    2035    ///     0x19u8, 0x18u8, 0x17u8, 0x16u8, 0x15u8, 0x14u8, 0x13u8, 0x12u8,
    2036    ///     0x11u8, 0x10u8, 0x0fu8, 0x0eu8, 0x0du8, 0x0cu8, 0x0bu8, 0x0au8,
    2037    /// ]);
    2038    /// assert_eq!(
    2039    ///     Ipv6Addr::new(
    2040    ///         0x1918, 0x1716, 0x1514, 0x1312,
    2041    ///         0x1110, 0x0f0e, 0x0d0c, 0x0b0a,
    2042    ///     ),
    2043    ///     addr
    2044    /// );
    2045    /// ```
    2046    #[stable(feature = "ip_from", since = "1.91.0")]
    2047    #[rustc_const_stable(feature = "ip_from", since = "1.91.0")]
    2048    #[must_use]
    2049    #[inline]
    2050    pub const fn from_octets(octets: [u8; 16]) -> Ipv6Addr {
    2051        Ipv6Addr { octets }
    2052    }
    2053
    2054    /// Returns the sixteen eight-bit integers the IPv6 address consists of
    2055    /// as a slice.
    2056    ///
    2057    /// # Examples
    2058    ///
    2059    /// ```
    2060    /// #![feature(ip_as_octets)]
    2061    ///
    2062    /// use std::net::Ipv6Addr;
    2063    ///
    2064    /// assert_eq!(Ipv6Addr::new(0xff00, 0, 0, 0, 0, 0, 0, 0).as_octets(),
    2065    ///            &[255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])
    2066    /// ```
    2067    #[unstable(feature = "ip_as_octets", issue = "137259")]
    2068    #[inline]
    2069    pub const fn as_octets(&self) -> &[u8; 16] {
    2070        &self.octets
    2071    }
    2072}
    2073
    2074/// Writes an Ipv6Addr, conforming to the canonical style described by
    2075/// [RFC 5952](https://tools.ietf.org/html/rfc5952).
    2076#[stable(feature = "rust1", since = "1.0.0")]
    2077impl fmt::Display for Ipv6Addr {
    2078    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
    2079        // If there are no alignment requirements, write the IP address directly to `f`.
    2080        // Otherwise, write it to a local buffer and then use `f.pad`.
    2081        if f.precision().is_none() && f.width().is_none() {
    2082            let segments = self.segments();
    2083
    2084            if let Some(ipv4) = self.to_ipv4_mapped() {
    2085                write!(f, "::ffff:{}", ipv4)
    2086            } else {
    2087                #[derive(Copy, Clone, Default)]
    2088                struct Span {
    2089                    start: usize,
    2090                    len: usize,
    2091                }
    2092
    2093                // Find the inner 0 span
    2094                let zeroes = {
    2095                    let mut longest = Span::default();
    2096                    let mut current = Span::default();
    2097
    2098                    for (i, &segment) in segments.iter().enumerate() {
    2099                        if segment == 0 {
    2100                            if current.len == 0 {
    2101                                current.start = i;
    2102                            }
    2103
    2104                            current.len += 1;
    2105
    2106                            if current.len > longest.len {
    2107                                longest = current;
    2108                            }
    2109                        } else {
    2110                            current = Span::default();
    2111                        }
    2112                    }
    2113
    2114                    longest
    2115                };
    2116
    2117                /// Writes a colon-separated part of the address.
    2118                #[inline]
    2119                fn fmt_subslice(f: &mut fmt::Formatter<'_>, chunk: &[u16]) -> fmt::Result {
    2120                    if let Some((first, tail)) = chunk.split_first() {
    2121                        write!(f, "{:x}", first)?;
    2122                        for segment in tail {
    2123                            f.write_char(':')?;
    2124                            write!(f, "{:x}", segment)?;
    2125                        }
    2126                    }
    2127                    Ok(())
    2128                }
    2129
    2130                if zeroes.len > 1 {
    2131                    fmt_subslice(f, &segments[..zeroes.start])?;
    2132                    f.write_str("::")?;
    2133                    fmt_subslice(f, &segments[zeroes.start + zeroes.len..])
    2134                } else {
    2135                    fmt_subslice(f, &segments)
    2136                }
    2137            }
    2138        } else {
    2139            const LONGEST_IPV6_ADDR: &str = "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff";
    2140
    2141            let mut buf = DisplayBuffer::<{ LONGEST_IPV6_ADDR.len() }>::new();
    2142            // Buffer is long enough for the longest possible IPv6 address, so this should never fail.
    2143            write!(buf, "{}", self).unwrap();
    2144
    2145            f.pad(buf.as_str())
    2146        }
    2147    }
    2148}
    2149
    2150#[stable(feature = "rust1", since = "1.0.0")]
    2151impl fmt::Debug for Ipv6Addr {
    2152    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
    2153        fmt::Display::fmt(self, fmt)
    2154    }
    2155}
    2156
    2157#[stable(feature = "ip_cmp", since = "1.16.0")]
    2158impl PartialEq<IpAddr> for Ipv6Addr {
    2159    #[inline]
    2160    fn eq(&self, other: &IpAddr) -> bool {
    2161        match other {
    2162            IpAddr::V4(_) => false,
    2163            IpAddr::V6(v6) => self == v6,
    2164        }
    2165    }
    2166}
    2167
    2168#[stable(feature = "ip_cmp", since = "1.16.0")]
    2169impl PartialEq<Ipv6Addr> for IpAddr {
    2170    #[inline]
    2171    fn eq(&self, other: &Ipv6Addr) -> bool {
    2172        match self {
    2173            IpAddr::V4(_) => false,
    2174            IpAddr::V6(v6) => v6 == other,
    2175        }
    2176    }
    2177}
    2178
    2179#[stable(feature = "rust1", since = "1.0.0")]
    2180impl PartialOrd for Ipv6Addr {
    2181    #[inline]
    2182    fn partial_cmp(&self, other: &Ipv6Addr) -> Option<Ordering> {
    2183        Some(self.cmp(other))
    2184    }
    2185}
    2186
    2187#[stable(feature = "ip_cmp", since = "1.16.0")]
    2188impl PartialOrd<Ipv6Addr> for IpAddr {
    2189    #[inline]
    2190    fn partial_cmp(&self, other: &Ipv6Addr) -> Option<Ordering> {
    2191        match self {
    2192            IpAddr::V4(_) => Some(Ordering::Less),
    2193            IpAddr::V6(v6) => v6.partial_cmp(other),
    2194        }
    2195    }
    2196}
    2197
    2198#[stable(feature = "ip_cmp", since = "1.16.0")]
    2199impl PartialOrd<IpAddr> for Ipv6Addr {
    2200    #[inline]
    2201    fn partial_cmp(&self, other: &IpAddr) -> Option<Ordering> {
    2202        match other {
    2203            IpAddr::V4(_) => Some(Ordering::Greater),
    2204            IpAddr::V6(v6) => self.partial_cmp(v6),
    2205        }
    2206    }
    2207}
    2208
    2209#[stable(feature = "rust1", since = "1.0.0")]
    2210impl Ord for Ipv6Addr {
    2211    #[inline]
    2212    fn cmp(&self, other: &Ipv6Addr) -> Ordering {
    2213        self.segments().cmp(&other.segments())
    2214    }
    2215}
    2216
    2217#[stable(feature = "i128", since = "1.26.0")]
    2218#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    2219impl const From<Ipv6Addr> for u128 {
    2220    /// Uses [`Ipv6Addr::to_bits`] to convert an IPv6 address to a host byte order `u128`.
    2221    #[inline]
    2222    fn from(ip: Ipv6Addr) -> u128 {
    2223        ip.to_bits()
    2224    }
    2225}
    2226#[stable(feature = "i128", since = "1.26.0")]
    2227#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    2228impl const From<u128> for Ipv6Addr {
    2229    /// Uses [`Ipv6Addr::from_bits`] to convert a host byte order `u128` to an IPv6 address.
    2230    #[inline]
    2231    fn from(ip: u128) -> Ipv6Addr {
    2232        Ipv6Addr::from_bits(ip)
    2233    }
    2234}
    2235
    2236#[stable(feature = "ipv6_from_octets", since = "1.9.0")]
    2237#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    2238impl const From<[u8; 16]> for Ipv6Addr {
    2239    /// Creates an `Ipv6Addr` from a sixteen element byte array.
    2240    ///
    2241    /// # Examples
    2242    ///
    2243    /// ```
    2244    /// use std::net::Ipv6Addr;
    2245    ///
    2246    /// let addr = Ipv6Addr::from([
    2247    ///     0x19u8, 0x18u8, 0x17u8, 0x16u8, 0x15u8, 0x14u8, 0x13u8, 0x12u8,
    2248    ///     0x11u8, 0x10u8, 0x0fu8, 0x0eu8, 0x0du8, 0x0cu8, 0x0bu8, 0x0au8,
    2249    /// ]);
    2250    /// assert_eq!(
    2251    ///     Ipv6Addr::new(
    2252    ///         0x1918, 0x1716, 0x1514, 0x1312,
    2253    ///         0x1110, 0x0f0e, 0x0d0c, 0x0b0a,
    2254    ///     ),
    2255    ///     addr
    2256    /// );
    2257    /// ```
    2258    #[inline]
    2259    fn from(octets: [u8; 16]) -> Ipv6Addr {
    2260        Ipv6Addr { octets }
    2261    }
    2262}
    2263
    2264#[stable(feature = "ipv6_from_segments", since = "1.16.0")]
    2265#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    2266impl const From<[u16; 8]> for Ipv6Addr {
    2267    /// Creates an `Ipv6Addr` from an eight element 16-bit array.
    2268    ///
    2269    /// # Examples
    2270    ///
    2271    /// ```
    2272    /// use std::net::Ipv6Addr;
    2273    ///
    2274    /// let addr = Ipv6Addr::from([
    2275    ///     0x20du16, 0x20cu16, 0x20bu16, 0x20au16,
    2276    ///     0x209u16, 0x208u16, 0x207u16, 0x206u16,
    2277    /// ]);
    2278    /// assert_eq!(
    2279    ///     Ipv6Addr::new(
    2280    ///         0x20d, 0x20c, 0x20b, 0x20a,
    2281    ///         0x209, 0x208, 0x207, 0x206,
    2282    ///     ),
    2283    ///     addr
    2284    /// );
    2285    /// ```
    2286    #[inline]
    2287    fn from(segments: [u16; 8]) -> Ipv6Addr {
    2288        let [a, b, c, d, e, f, g, h] = segments;
    2289        Ipv6Addr::new(a, b, c, d, e, f, g, h)
    2290    }
    2291}
    2292
    2293#[stable(feature = "ip_from_slice", since = "1.17.0")]
    2294#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    2295impl const From<[u8; 16]> for IpAddr {
    2296    /// Creates an `IpAddr::V6` from a sixteen element byte array.
    2297    ///
    2298    /// # Examples
    2299    ///
    2300    /// ```
    2301    /// use std::net::{IpAddr, Ipv6Addr};
    2302    ///
    2303    /// let addr = IpAddr::from([
    2304    ///     0x19u8, 0x18u8, 0x17u8, 0x16u8, 0x15u8, 0x14u8, 0x13u8, 0x12u8,
    2305    ///     0x11u8, 0x10u8, 0x0fu8, 0x0eu8, 0x0du8, 0x0cu8, 0x0bu8, 0x0au8,
    2306    /// ]);
    2307    /// assert_eq!(
    2308    ///     IpAddr::V6(Ipv6Addr::new(
    2309    ///         0x1918, 0x1716, 0x1514, 0x1312,
    2310    ///         0x1110, 0x0f0e, 0x0d0c, 0x0b0a,
    2311    ///     )),
    2312    ///     addr
    2313    /// );
    2314    /// ```
    2315    #[inline]
    2316    fn from(octets: [u8; 16]) -> IpAddr {
    2317        IpAddr::V6(Ipv6Addr::from(octets))
    2318    }
    2319}
    2320
    2321#[stable(feature = "ip_from_slice", since = "1.17.0")]
    2322#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
    2323impl const From<[u16; 8]> for IpAddr {
    2324    /// Creates an `IpAddr::V6` from an eight element 16-bit array.
    2325    ///
    2326    /// # Examples
    2327    ///
    2328    /// ```
    2329    /// use std::net::{IpAddr, Ipv6Addr};
    2330    ///
    2331    /// let addr = IpAddr::from([
    2332    ///     0x20du16, 0x20cu16, 0x20bu16, 0x20au16,
    2333    ///     0x209u16, 0x208u16, 0x207u16, 0x206u16,
    2334    /// ]);
    2335    /// assert_eq!(
    2336    ///     IpAddr::V6(Ipv6Addr::new(
    2337    ///         0x20d, 0x20c, 0x20b, 0x20a,
    2338    ///         0x209, 0x208, 0x207, 0x206,
    2339    ///     )),
    2340    ///     addr
    2341    /// );
    2342    /// ```
    2343    #[inline]
    2344    fn from(segments: [u16; 8]) -> IpAddr {
    2345        IpAddr::V6(Ipv6Addr::from(segments))
    2346    }
    2347}
    2348
    2349#[stable(feature = "ip_bitops", since = "1.75.0")]
    2350#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
    2351impl const Not for Ipv4Addr {
    2352    type Output = Ipv4Addr;
    2353
    2354    #[inline]
    2355    fn not(mut self) -> Ipv4Addr {
    2356        let mut idx = 0;
    2357        while idx < 4 {
    2358            self.octets[idx] = !self.octets[idx];
    2359            idx += 1;
    2360        }
    2361        self
    2362    }
    2363}
    2364
    2365#[stable(feature = "ip_bitops", since = "1.75.0")]
    2366#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
    2367impl const Not for &'_ Ipv4Addr {
    2368    type Output = Ipv4Addr;
    2369
    2370    #[inline]
    2371    fn not(self) -> Ipv4Addr {
    2372        !*self
    2373    }
    2374}
    2375
    2376#[stable(feature = "ip_bitops", since = "1.75.0")]
    2377#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
    2378impl const Not for Ipv6Addr {
    2379    type Output = Ipv6Addr;
    2380
    2381    #[inline]
    2382    fn not(mut self) -> Ipv6Addr {
    2383        let mut idx = 0;
    2384        while idx < 16 {
    2385            self.octets[idx] = !self.octets[idx];
    2386            idx += 1;
    2387        }
    2388        self
    2389    }
    2390}
    2391
    2392#[stable(feature = "ip_bitops", since = "1.75.0")]
    2393#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
    2394impl const Not for &'_ Ipv6Addr {
    2395    type Output = Ipv6Addr;
    2396
    2397    #[inline]
    2398    fn not(self) -> Ipv6Addr {
    2399        !*self
    2400    }
    2401}
    2402
    2403macro_rules! bitop_impls {
    2404    ($(
    2405        $(#[$attr:meta])*
    2406        impl ($BitOp:ident, $BitOpAssign:ident) for $ty:ty = ($bitop:ident, $bitop_assign:ident);
    2407    )*) => {
    2408        $(
    2409            $(#[$attr])*
    2410            impl const $BitOpAssign for $ty {
    2411                fn $bitop_assign(&mut self, rhs: $ty) {
    2412                    let mut idx = 0;
    2413                    while idx < self.octets.len() {
    2414                        self.octets[idx].$bitop_assign(rhs.octets[idx]);
    2415                        idx += 1;
    2416                    }
    2417                }
    2418            }
    2419
    2420            $(#[$attr])*
    2421            impl const $BitOpAssign<&'_ $ty> for $ty {
    2422                fn $bitop_assign(&mut self, rhs: &'_ $ty) {
    2423                    self.$bitop_assign(*rhs);
    2424                }
    2425            }
    2426
    2427            $(#[$attr])*
    2428            impl const $BitOp for $ty {
    2429                type Output = $ty;
    2430
    2431                #[inline]
    2432                fn $bitop(mut self, rhs: $ty) -> $ty {
    2433                    self.$bitop_assign(rhs);
    2434                    self
    2435                }
    2436            }
    2437
    2438            $(#[$attr])*
    2439            impl const $BitOp<&'_ $ty> for $ty {
    2440                type Output = $ty;
    2441
    2442                #[inline]
    2443                fn $bitop(mut self, rhs: &'_ $ty) -> $ty {
    2444                    self.$bitop_assign(*rhs);
    2445                    self
    2446                }
    2447            }
    2448
    2449            $(#[$attr])*
    2450            impl const $BitOp<$ty> for &'_ $ty {
    2451                type Output = $ty;
    2452
    2453                #[inline]
    2454                fn $bitop(self, rhs: $ty) -> $ty {
    2455                    let mut lhs = *self;
    2456                    lhs.$bitop_assign(rhs);
    2457                    lhs
    2458                }
    2459            }
    2460
    2461            $(#[$attr])*
    2462            impl const $BitOp<&'_ $ty> for &'_ $ty {
    2463                type Output = $ty;
    2464
    2465                #[inline]
    2466                fn $bitop(self, rhs: &'_ $ty) -> $ty {
    2467                    let mut lhs = *self;
    2468                    lhs.$bitop_assign(*rhs);
    2469                    lhs
    2470                }
    2471            }
    2472        )*
    2473    };
    2474}
    2475
    2476bitop_impls! {
    2477    #[stable(feature = "ip_bitops", since = "1.75.0")]
    2478    #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
    2479    impl (BitAnd, BitAndAssign) for Ipv4Addr = (bitand, bitand_assign);
    2480    #[stable(feature = "ip_bitops", since = "1.75.0")]
    2481    #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
    2482    impl (BitOr, BitOrAssign) for Ipv4Addr = (bitor, bitor_assign);
    2483
    2484    #[stable(feature = "ip_bitops", since = "1.75.0")]
    2485    #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
    2486    impl (BitAnd, BitAndAssign) for Ipv6Addr = (bitand, bitand_assign);
    2487    #[stable(feature = "ip_bitops", since = "1.75.0")]
    2488    #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
    2489    impl (BitOr, BitOrAssign) for Ipv6Addr = (bitor, bitor_assign);
    2490}