Tracking Issue for #138744: Add methods to TCP and UDP sockets to modify IPv6 hop limits

[Mallets]

Feature gate: #![feature(ipv6_hop_limit)]

This is a tracking issue for adding methods to set the values for IPV6_UNICAST_HOPS and IPV6_MULTICAST_HOPS on TCP and UDP ipv6 sockets.

Public API

TCP sockets

impl TcpStream {
  /// #![feature(ipv6_hop_limit)]
  /// use std::net::TcpStream;
  ///
  /// let stream = TcpStream::connect("[::1]:12345")
  ///                        .expect("Couldn't connect to the server...");
  /// stream.set_hop_limit_v6(88).expect("set_hop_limit_v6 call failed");
  /// ```
  pub fn set_hop_limit_v6(&self, limit: u8) -> io::Result<()>;

  /// Gets the value of the `IPV6_UNICAST_HOPS` option on this socket.
  ///
  /// For more information about this option, see [`TcpStream::set_hop_limit_v6`].
  ///
  /// # Examples
  ///
  /// ```no_run
  /// #![feature(ipv6_hop_limit)]
  /// use std::net::TcpStream;
  ///
  /// let stream = TcpStream::connect("[::1]:12345")
  ///                        .expect("Couldn't connect to the server...");
  /// stream.set_hop_limit_v6(88).expect("set_hop_limit_v6 call failed");
  /// assert_eq!(stream.hop_limit_v6().unwrap(), 88);
  /// ```
  pub fn hop_limit_v6(&self) -> io::Result<u8>;
}

impl TcpListener {
  /// Sets the value for the `IPV6_UNICAST_HOPS` option on this socket.
  ///
  /// This value sets the unicast hop limit field that is used in every packet
  /// sent from this socket.
  ///
  /// # Examples
  ///
  /// ```no_run
  /// #![feature(ipv6_hop_limit)]
  /// use std::net::TcpListener;
  ///
  /// let listener = TcpListener::bind("[::1]:12345").unwrap();
  /// listener.set_hop_limit_v6(88).expect("set_hop_limit_v6 call failed");
  /// ```
  pub fn set_hop_limit_v6(&self, limit: u8) -> io::Result<()>;

  /// Gets the value of the `IPV6_UNICAST_HOPS` option on this socket.
  ///
  /// For more information about this option, see [`TcpListener::set_hop_limit_v6`].
  ///
  /// # Examples
  ///
  /// ```no_run
  /// #![feature(ipv6_hop_limit)]
  /// use std::net::TcpListener;
  ///
  /// let listener = TcpListener::bind("[::1]:12345").unwrap();
  /// listener.set_hop_limit_v6(88).expect("set_hop_limit_v6 call failed");
  /// assert_eq!(listener.hop_limit_v6().unwrap(), 88);
  /// ```
  pub fn hop_limit_v6(&self) -> io::Result<u8>;
}

UDP sockets

impl UdpSocket {
  /// Sets the value for the `IPV6_UNICAST_HOPS` option on this socket.
  ///
  /// This value sets the unicast hop limit field that is used in every packet
  /// sent from this socket.
  ///
  /// # Examples
  ///
  /// ```no_run
  /// #![feature(ipv6_hop_limit)]
  /// use std::net::UdpSocket;
  ///
  /// let socket = UdpSocket::bind("[::1]:12345").expect("couldn't bind to address");
  /// socket.set_hop_limit_v6(88).expect("set_hop_limit_v6 call failed");
  /// ```
  pub fn set_hop_limit_v6(&self, limit: u8) -> io::Result<()>;

  /// Gets the value of the `IPV6_UNICAST_HOPS` option on this socket.
  ///
  /// For more information about this option, see [`UdpSocket::set_hop_limit_v6`].
  ///
  /// # Examples
  ///
  /// ```no_run
  /// #![feature(ipv6_hop_limit)]
  /// use std::net::UdpSocket;
  ///
  /// let socket = UdpSocket::bind("[::1]:12345").expect("couldn't bind to address");
  /// socket.set_hop_limit_v6(88).expect("set_hop_limit_v6 call failed");
  /// assert_eq!(socket.hop_limit_v6().unwrap(), 88);
  /// ```
  pub fn hop_limit_v6(&self) -> io::Result<u8>;

  /// Sets the value for the `IPV6_MULTICAST_HOPS` option on this socket.
  ///
  /// This value sets the hop limit field for outgoing multicast packets sent from this socket.
  ///
  /// # Examples
  ///
  /// ```no_run
  /// #![feature(ipv6_hop_limit)]
  /// use std::net::UdpSocket;
  ///
  /// let socket = UdpSocket::bind("[::1]:12345").expect("couldn't bind to address");
  /// socket.set_multicast_hop_limit_v6(88).expect("set_multicast_hop_limit_v6 call failed");
  /// ```
  pub fn set_multicast_hop_limit_v6(&self, limit: u8) -> io::Result<()>;

  /// Gets the value of the `IPV6_MULTICAST_HOPS` option on this socket.
  ///
  /// # Examples
  ///
  /// ```no_run
  /// #![feature(ipv6_hop_limit)]
  /// use std::net::UdpSocket;
  ///
  /// let socket = UdpSocket::bind("[::1]:12345").expect("couldn't bind to address");
  /// socket.set_multicast_hop_limit_v6(88).expect("set_multicast_hop_limit_v6 call failed");
  /// assert_eq!(socket.multicast_hop_limit_v6().unwrap(), 88);
  /// ```
  pub fn multicast_hop_limit_v6(&self) -> io::Result<u8>;
}

Steps

• Implementation:
  • unstable Add methods to TCP and UDP sockets to modify hop limit (refresh of #94678) #138744
• Final comment period (FCP)¹
• Stabilization PR

History

• Original issue UdpSocket::set_ttl does not set IPv6 hoplimit field #47727
• First (abandoned) implementation add methods to TCP and UDP sockets to modify hop limit #94678

Unresolved Questions

• None yet.

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩