/// IPv6 addresses are defined as 128-bit integers in [IETF RFC 4291].
/// They are usually represented as eight 16-bit segments.
///
-/// See [`IpAddr`] for a type encompassing both IPv4 and IPv6 addresses.
-///
/// The size of an `Ipv6Addr` struct may vary depending on the target operating
/// system.
///
/// [IETF RFC 4291]: https://tools.ietf.org/html/rfc4291
///
+/// # Embedding IPv4 Addresses
+///
+/// See [`IpAddr`] for a type encompassing both IPv4 and IPv6 addresses.
+///
+/// To assist in the transition from IPv4 to IPv6 two types of IPv6 addresses that embed an IPv4 address were defined:
+/// IPv4-compatible and IPv4-mapped addresses. Of these IPv4-compatible addresses have been officially deprecated.
+///
+/// Both types of addresses are not assigned any special meaning by this implementation,
+/// other than what the relevant standards prescribe. This means that an address like `::ffff:127.0.0.1`,
+/// while representing an IPv4 loopback address, is not itself an IPv6 loopback address; only `::1` is.
+/// To handle these so called "IPv4-in-IPv6" addresses, they have to first be converted to their canonical IPv4 address.
+///
+/// ### IPv4-Compatible IPv6 Addresses
+///
+/// IPv4-compatible IPv6 addresses are defined in [IETF RFC 4291 Section 2.5.5.1], and have been officially deprecated.
+/// The RFC describes the format of an "IPv4-Compatible IPv6 address" as follows:
+///
+/// ```text
+/// | 80 bits | 16 | 32 bits |
+/// +--------------------------------------+--------------------------+
+/// |0000..............................0000|0000| IPv4 address |
+/// +--------------------------------------+----+---------------------+
+/// ```
+/// So `::a.b.c.d` would be an IPv4-compatible IPv6 address representing the IPv4 address `a.b.c.d`.
+///
+/// To convert from an IPv4 address to an IPv4-compatible IPv6 address, use [`Ipv4Addr::to_ipv6_compatible`].
+/// Use [`Ipv6Addr::to_ipv4`] to convert an IPv4-compatible IPv6 address to the canonical IPv4 address.
+///
+/// [IETF RFC 4291 Section 2.5.5.1]: https://datatracker.ietf.org/doc/html/rfc4291#section-2.5.5.1
+///
+/// ### IPv4-Mapped IPv6 Addresses
+///
+/// IPv4-mapped IPv6 addresses are defined in [IETF RFC 4291 Section 2.5.5.2].
+/// The RFC describes the format of an "IPv4-Mapped IPv6 address" as follows:
+///
+/// ```text
+/// | 80 bits | 16 | 32 bits |
+/// +--------------------------------------+--------------------------+
+/// |0000..............................0000|FFFF| IPv4 address |
+/// +--------------------------------------+----+---------------------+
+/// ```
+/// So `::ffff:a.b.c.d` would be an IPv4-mapped IPv6 address representing the IPv4 address `a.b.c.d`.
+///
+/// To convert from an IPv4 address to an IPv4-mapped IPv6 address, use [`Ipv4Addr::to_ipv6_mapped`].
+/// Use [`Ipv6Addr::to_ipv4`] to convert an IPv4-mapped IPv6 address to the canonical IPv4 address.
+///
+/// [IETF RFC 4291 Section 2.5.5.2]: https://datatracker.ietf.org/doc/html/rfc4291#section-2.5.5.2
+///
/// # Textual representation
///
/// `Ipv6Addr` provides a [`FromStr`] implementation. There are many ways to represent
pub const fn is_ipv6(&self) -> bool {
matches!(self, IpAddr::V6(_))
}
+
+ /// Converts this address to an `IpAddr::V4` if it is a IPv4-mapped IPv6 addresses, otherwise it
+ /// return `self` as-is.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(ip)]
+ /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+ ///
+ /// assert_eq!(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)).to_canonical().is_loopback(), true);
+ /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0x7f00, 0x1)).is_loopback(), false);
+ /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0x7f00, 0x1)).to_canonical().is_loopback(), true);
+ /// ```
+ #[inline]
+ #[rustc_const_unstable(feature = "const_ip", issue = "76205")]
+ #[unstable(feature = "ip", issue = "27709")]
+ pub const fn to_canonical(&self) -> IpAddr {
+ match self {
+ &v4 @ IpAddr::V4(_) => v4,
+ IpAddr::V6(v6) => v6.to_canonical(),
+ }
+ }
}
impl Ipv4Addr {
}
}
- /// Converts this address to an IPv4-compatible [`IPv6` address].
+ /// Converts this address to an [IPv4-compatible] [`IPv6` address].
///
/// `a.b.c.d` becomes `::a.b.c.d`
///
- /// This isn't typically the method you want; these addresses don't typically
- /// function on modern systems. Use `to_ipv6_mapped` instead.
+ /// Note that IPv4-compatible addresses have been officially deprecated.
+ /// If you don't explicitly need an IPv4-compatible address for legacy reasons, consider using `to_ipv6_mapped` instead.
///
+ /// [IPv4-compatible]: Ipv6Addr#ipv4-compatible-ipv6-addresses
/// [`IPv6` address]: Ipv6Addr
///
/// # Examples
}
}
- /// Converts this address to an IPv4-mapped [`IPv6` address].
+ /// Converts this address to an [IPv4-mapped] [`IPv6` address].
///
/// `a.b.c.d` becomes `::ffff:a.b.c.d`
///
+ /// [IPv4-mapped]: Ipv6Addr#ipv4-mapped-ipv6-addresses
/// [`IPv6` address]: Ipv6Addr
///
/// # Examples
u128::from_be_bytes(self.octets()) == u128::from_be_bytes(Ipv6Addr::UNSPECIFIED.octets())
}
- /// Returns [`true`] if this is a loopback address (::1).
+ /// Returns [`true`] if this is the [loopback address] (`::1`),
+ /// as defined in [IETF RFC 4291 section 2.5.3].
///
- /// This property is defined in [IETF RFC 4291].
+ /// Contrary to IPv4, in IPv6 there is only one loopback address.
///
- /// [IETF RFC 4291]: https://tools.ietf.org/html/rfc4291
+ /// [loopback address]: Ipv6Addr::LOCALHOST
+ /// [IETF RFC 4291 section 2.5.3]: https://tools.ietf.org/html/rfc4291#section-2.5.3
///
/// # Examples
///
(self.segments()[0] & 0xff00) == 0xff00
}
- /// Converts this address to an [`IPv4` address] if it's an "IPv4-mapped IPv6 address"
- /// defined in [IETF RFC 4291 section 2.5.5.2], otherwise returns [`None`].
+ /// Converts this address to an [`IPv4` address] if it's an [IPv4-mapped] address,
+ /// as defined in [IETF RFC 4291 section 2.5.5.2], otherwise returns [`None`].
///
/// `::ffff:a.b.c.d` becomes `a.b.c.d`.
/// All addresses *not* starting with `::ffff` will return `None`.
///
/// [`IPv4` address]: Ipv4Addr
+ /// [IPv4-mapped]: Ipv6Addr
/// [IETF RFC 4291 section 2.5.5.2]: https://tools.ietf.org/html/rfc4291#section-2.5.5.2
///
/// # Examples
}
}
- /// Converts this address to an [`IPv4` address]. Returns [`None`] if this address is
- /// neither IPv4-compatible or IPv4-mapped.
+ /// Converts this address to an [`IPv4` address] if it is either
+ /// an [IPv4-compatible] address as defined in [IETF RFC 4291 section 2.5.5.1],
+ /// or an [IPv4-mapped] address as defined in [IETF RFC 4291 section 2.5.5.2],
+ /// otherwise returns [`None`].
///
/// `::a.b.c.d` and `::ffff:a.b.c.d` become `a.b.c.d`
+ /// All addresses *not* starting with either all zeroes or `::ffff` will return `None`.
///
- /// [`IPv4` address]: Ipv4Addr
+ /// [IPv4 address]: Ipv4Addr
+ /// [IPv4-compatible]: Ipv6Addr#ipv4-compatible-ipv6-addresses
+ /// [IPv4-mapped]: Ipv6Addr#ipv4-mapped-ipv6-addresses
+ /// [IETF RFC 4291 section 2.5.5.1]: https://tools.ietf.org/html/rfc4291#section-2.5.5.1
+ /// [IETF RFC 4291 section 2.5.5.2]: https://tools.ietf.org/html/rfc4291#section-2.5.5.2
///
/// # Examples
///
}
}
+ /// Converts this address to an `IpAddr::V4` if it is a IPv4-mapped addresses, otherwise it
+ /// returns self wrapped in a `IpAddr::V6`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(ip)]
+ /// use std::net::Ipv6Addr;
+ ///
+ /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0x7f00, 0x1).is_loopback(), false);
+ /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0x7f00, 0x1).to_canonical().is_loopback(), true);
+ /// ```
+ #[inline]
+ #[rustc_const_unstable(feature = "const_ipv6", issue = "76205")]
+ #[unstable(feature = "ip", issue = "27709")]
+ pub const fn to_canonical(&self) -> IpAddr {
+ if let Some(mapped) = self.to_ipv4_mapped() {
+ return IpAddr::V4(mapped);
+ }
+ IpAddr::V6(*self)
+ }
+
/// Returns the sixteen eight-bit integers the IPv6 address consists of.
///
/// ```
projects / rust.git / blobdiff