Rollup merge of rust-lang#138744 - Mallets:set_ipv6_sock_hop_limit, r=dtolnay

Add methods to TCP and UDP sockets to modify hop limit (refresh of rust-lang#94678)

rust-lang#94678 was closed because of time constraints of the original author (``@kckeiks).``

This PR is a refresh of rust-lang#94678 where the original proposed changes are ported to the current status of the standard library.

In addition, this PR:
- implements the change suggested in rust-lang#94678 (comment)
- defines `set_multicast_hop_limit_v6` and `multicast_hop_limit_v6 ` only for UDP sockets and not for TCP sockets as originally proposed

Issue: rust-lang#139166

Author: ChrisDenton

Diff for: library/std/src/lib.rs

@@ -349,6 +349,7 @@
 #![feature(hashmap_internals)]
 #![feature(hint_must_use)]
 #![feature(ip)]
+#![feature(ipv6_hop_limit)]
 #![feature(lazy_get)]
 #![feature(maybe_uninit_slice)]
 #![feature(maybe_uninit_write_slice)]

Diff for: library/std/src/net/tcp.rs

@@ -548,6 +548,46 @@ impl TcpStream {
         self.0.ttl()
     }
 
+    /// 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::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");
+    /// ```
+    #[unstable(feature = "ipv6_hop_limit", issue = "139166")]
+    pub fn set_hop_limit_v6(&self, limit: u8) -> io::Result<()> {
+        self.0.set_hop_limit_v6(limit)
+    }
+
+    /// 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);
+    /// ```
+    #[unstable(feature = "ipv6_hop_limit", issue = "139166")]
+    pub fn hop_limit_v6(&self) -> io::Result<u8> {
+        self.0.hop_limit_v6()
+    }
+
     /// Gets the value of the `SO_ERROR` option on this socket.
     ///
     /// This will retrieve the stored error in the underlying socket, clearing
@@ -942,6 +982,44 @@ impl TcpListener {
         self.0.ttl()
     }
 
+    /// 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");
+    /// ```
+    #[unstable(feature = "ipv6_hop_limit", issue = "139166")]
+    pub fn set_hop_limit_v6(&self, limit: u8) -> io::Result<()> {
+        self.0.set_hop_limit_v6(limit)
+    }
+
+    /// 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);
+    /// ```
+    #[unstable(feature = "ipv6_hop_limit", issue = "139166")]
+    pub fn hop_limit_v6(&self) -> io::Result<u8> {
+        self.0.hop_limit_v6()
+    }
+
     #[stable(feature = "net2_mutators", since = "1.9.0")]
     #[deprecated(since = "1.16.0", note = "this option can only be set before the socket is bound")]
     #[allow(missing_docs)]

Diff for: library/std/src/net/tcp/tests.rs

@@ -875,6 +875,23 @@ fn ttl() {
     assert_eq!(ttl, t!(stream.ttl()));
 }
 
+#[test]
+#[cfg_attr(target_env = "sgx", ignore)]
+fn hop_limit() {
+    let hlim = 100;
+
+    let addr = next_test_ip6();
+    let listener = t!(TcpListener::bind(&addr));
+
+    t!(listener.set_hop_limit_v6(hlim));
+    assert_eq!(hlim, t!(listener.hop_limit_v6()));
+
+    let stream = t!(TcpStream::connect(&addr));
+
+    t!(stream.set_hop_limit_v6(hlim));
+    assert_eq!(hlim, t!(stream.hop_limit_v6()));
+}
+
 #[test]
 #[cfg_attr(target_env = "sgx", ignore)]
 fn set_nonblocking() {

Diff for: library/std/src/net/udp.rs

@@ -582,6 +582,82 @@ impl UdpSocket {
         self.0.ttl()
     }
 
+    /// 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");
+    /// ```
+    #[unstable(feature = "ipv6_hop_limit", issue = "139166")]
+    pub fn set_hop_limit_v6(&self, limit: u8) -> io::Result<()> {
+        self.0.set_hop_limit_v6(limit)
+    }
+
+    /// 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);
+    /// ```
+    #[unstable(feature = "ipv6_hop_limit", issue = "139166")]
+    pub fn hop_limit_v6(&self) -> io::Result<u8> {
+        self.0.hop_limit_v6()
+    }
+
+    /// 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");
+    /// ```
+    #[unstable(feature = "ipv6_hop_limit", issue = "139166")]
+    pub fn set_multicast_hop_limit_v6(&self, limit: u8) -> io::Result<()> {
+        self.0.set_multicast_hop_limit_v6(limit)
+    }
+
+    /// Gets the value of the `IPV6_MULTICAST_HOPS` option on this socket.
+    ///
+    /// For more information about this option, see [`UdpSocket::set_multicast_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_multicast_hop_limit_v6(88).expect("set_multicast_hop_limit_v6 call failed");
+    /// assert_eq!(socket.multicast_hop_limit_v6().unwrap(), 88);
+    /// ```
+    #[unstable(feature = "ipv6_hop_limit", issue = "139166")]
+    pub fn multicast_hop_limit_v6(&self) -> io::Result<u8> {
+        self.0.multicast_hop_limit_v6()
+    }
+
     /// Executes an operation of the `IP_ADD_MEMBERSHIP` type.
     ///
     /// This function specifies a new multicast group for this socket to join.

Diff for: library/std/src/net/udp/tests.rs

@@ -357,6 +357,18 @@ fn ttl() {
     assert_eq!(ttl, t!(stream.ttl()));
 }
 
+#[test]
+fn hop_limit() {
+    let hlim = 100;
+
+    let addr = next_test_ip6();
+
+    let stream = t!(UdpSocket::bind(&addr));
+
+    t!(stream.set_hop_limit_v6(hlim));
+    assert_eq!(hlim, t!(stream.hop_limit_v6()));
+}
+
 #[test]
 fn set_nonblocking() {
     each_ip(&mut |addr, _| {

Diff for: library/std/src/sys/net/connection/sgx.rs

@@ -8,6 +8,7 @@ use crate::time::Duration;
 use crate::{error, fmt};
 
 const DEFAULT_FAKE_TTL: u32 = 64;
+const DEFAULT_FAKE_HLIM: u8 = 64;
 
 #[derive(Debug, Clone)]
 pub struct Socket {
@@ -199,6 +200,14 @@ impl TcpStream {
         sgx_ineffective(DEFAULT_FAKE_TTL)
     }
 
+    pub fn set_hop_limit_v6(&self, _: u8) -> io::Result<()> {
+        sgx_ineffective(())
+    }
+
+    pub fn hop_limit_v6(&self) -> io::Result<u8> {
+        sgx_ineffective(DEFAULT_FAKE_HLIM)
+    }
+
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         Ok(None)
     }
@@ -277,6 +286,14 @@ impl TcpListener {
         sgx_ineffective(DEFAULT_FAKE_TTL)
     }
 
+    pub fn set_hop_limit_v6(&self, _: u8) -> io::Result<()> {
+        sgx_ineffective(())
+    }
+
+    pub fn hop_limit_v6(&self) -> io::Result<u8> {
+        sgx_ineffective(DEFAULT_FAKE_HLIM)
+    }
+
     pub fn set_only_v6(&self, _: bool) -> io::Result<()> {
         sgx_ineffective(())
     }
@@ -416,6 +433,22 @@ impl UdpSocket {
         self.0
     }
 
+    pub fn set_hop_limit_v6(&self, _: u8) -> io::Result<()> {
+        self.0
+    }
+
+    pub fn hop_limit_v6(&self) -> io::Result<u8> {
+        self.0
+    }
+
+    pub fn set_multicast_hop_limit_v6(&self, _: u8) -> io::Result<()> {
+        self.0
+    }
+
+    pub fn multicast_hop_limit_v6(&self) -> io::Result<u8> {
+        self.0
+    }
+
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         self.0
     }

Diff for: library/std/src/sys/net/connection/socket.rs

@@ -454,6 +454,15 @@ impl TcpStream {
         Ok(raw as u32)
     }
 
+    pub fn set_hop_limit_v6(&self, limit: u8) -> io::Result<()> {
+        setsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_UNICAST_HOPS, limit as c_int)
+    }
+
+    pub fn hop_limit_v6(&self) -> io::Result<u8> {
+        let raw: c_int = getsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_UNICAST_HOPS)?;
+        Ok(raw as u8)
+    }
+
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         self.inner.take_error()
     }
@@ -581,6 +590,15 @@ impl TcpListener {
         Ok(raw as u32)
     }
 
+    pub fn set_hop_limit_v6(&self, limit: u8) -> io::Result<()> {
+        setsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_UNICAST_HOPS, limit as c_int)
+    }
+
+    pub fn hop_limit_v6(&self) -> io::Result<u8> {
+        let raw: c_int = getsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_UNICAST_HOPS)?;
+        Ok(raw as u8)
+    }
+
     pub fn set_only_v6(&self, only_v6: bool) -> io::Result<()> {
         setsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_V6ONLY, only_v6 as c_int)
     }
@@ -786,6 +804,24 @@ impl UdpSocket {
         Ok(raw as u32)
     }
 
+    pub fn set_hop_limit_v6(&self, limit: u8) -> io::Result<()> {
+        setsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_UNICAST_HOPS, limit as c_int)
+    }
+
+    pub fn hop_limit_v6(&self) -> io::Result<u8> {
+        let raw: c_int = getsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_UNICAST_HOPS)?;
+        Ok(raw as u8)
+    }
+
+    pub fn set_multicast_hop_limit_v6(&self, limit: u8) -> io::Result<()> {
+        setsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_MULTICAST_HOPS, limit as c_int)
+    }
+
+    pub fn multicast_hop_limit_v6(&self) -> io::Result<u8> {
+        let raw: c_int = getsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_MULTICAST_HOPS)?;
+        Ok(raw as u8)
+    }
+
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         self.inner.take_error()
     }

Diff for: library/std/src/sys/net/connection/socket/windows.rs

@@ -30,10 +30,10 @@ pub(super) mod netc {
     pub use crate::sys::c::{
         ADDRESS_FAMILY as sa_family_t, ADDRINFOA as addrinfo, IP_ADD_MEMBERSHIP,
         IP_DROP_MEMBERSHIP, IP_MULTICAST_LOOP, IP_MULTICAST_TTL, IP_TTL, IPPROTO_IP, IPPROTO_IPV6,
-        IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP, IPV6_MULTICAST_LOOP, IPV6_V6ONLY, SO_BROADCAST,
-        SO_RCVTIMEO, SO_SNDTIMEO, SOCK_DGRAM, SOCK_STREAM, SOCKADDR as sockaddr,
-        SOCKADDR_STORAGE as sockaddr_storage, SOL_SOCKET, bind, connect, freeaddrinfo, getpeername,
-        getsockname, getsockopt, listen, setsockopt,
+        IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP, IPV6_MULTICAST_HOPS, IPV6_MULTICAST_LOOP,
+        IPV6_UNICAST_HOPS, IPV6_V6ONLY, SO_BROADCAST, SO_RCVTIMEO, SO_SNDTIMEO, SOCK_DGRAM,
+        SOCK_STREAM, SOCKADDR as sockaddr, SOCKADDR_STORAGE as sockaddr_storage, SOL_SOCKET, bind,
+        connect, freeaddrinfo, getpeername, getsockname, getsockopt, listen, setsockopt,
     };
 
     #[allow(non_camel_case_types)]