Add set_min_ttl_v4 and set_min_hopcount_v6

src/socket.rs

@@ -1631,6 +1631,28 @@ impl Socket {
         unsafe { setsockopt(self.as_raw(), sys::IPPROTO_IP, sys::IP_TTL, ttl as c_int) }
     }
 
+    /// Get the value of the `IP_MINTTL` option for this socket.
+    ///
+    /// For more information about this option, see [`set_min_ttl_v4`].
+    ///
+    /// [`set_min_ttl_v4`]: Socket::set_min_ttl_v4
+    #[cfg(all(feature = "all", any(target_os = "linux", target_os = "illumos")))]
+    pub fn min_ttl_v4(&self) -> io::Result<u32> {
+        unsafe {
+            getsockopt::<c_int>(self.as_raw(), sys::IPPROTO_IP, sys::IP_MINTTL)
+                .map(|ttl| ttl as u32)
+        }
+    }
+
+    /// Set the value of the `IP_MINTTL` option for this socket.
+    ///
+    /// If enabled, received IPv4 packets are discarded if the value of the
+    /// time-to-live field of the IPv4 header is lower than the option value.
+    #[cfg(all(feature = "all", any(target_os = "linux", target_os = "illumos")))]
+    pub fn set_min_ttl_v4(&self, ttl: u32) -> io::Result<()> {
+        unsafe { setsockopt(self.as_raw(), sys::IPPROTO_IP, sys::IP_MINTTL, ttl as c_int) }
+    }
+
     /// Set the value of the `IP_TOS` option for this socket.
     ///
     /// This value sets the type-of-service field that is used in every packet
@@ -2057,6 +2079,35 @@ impl Socket {
         }
     }
 
+    /// Get the value of the `IPV6_MINHOPCOUNT` option for this socket.
+    ///
+    /// For more information about this option, see [`set_min_hopcount_v6`].
+    ///
+    /// [`set_min_hopcount_v6`]: Socket::set_min_hopcount_v6
+    #[cfg(all(feature = "all", any(target_os = "linux", target_os = "illumos")))]
+    pub fn min_hopcount_v6(&self) -> io::Result<u32> {
+        unsafe {
+            getsockopt::<c_int>(self.as_raw(), sys::IPPROTO_IPV6, sys::IPV6_MINHOPCOUNT)
+                .map(|hops| hops as u32)
+        }
+    }
+
+    /// Set the value of the `IPV6_MINHOPCOUNT` option for this socket.
+    ///
+    /// If enabled, received IPv6 packets are discarded if the value of the
+    /// hop limit field of the IPv6 header is lower than the option value.
+    #[cfg(all(feature = "all", any(target_os = "linux", target_os = "illumos")))]
+    pub fn set_min_hopcount_v6(&self, hops: u32) -> io::Result<()> {
+        unsafe {
+            setsockopt(
+                self.as_raw(),
+                sys::IPPROTO_IPV6,
+                sys::IPV6_MINHOPCOUNT,
+                hops as c_int,
+            )
+        }
+    }
+
     /// Get the value of the `IPV6_V6ONLY` option for this socket.
     ///
     /// For more information about this option, see [`set_only_v6`].

src/sys/unix.rs

@@ -305,6 +305,8 @@ pub(crate) use libc::{IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP};
 pub(crate) use libc::{
     IPV6_JOIN_GROUP as IPV6_ADD_MEMBERSHIP, IPV6_LEAVE_GROUP as IPV6_DROP_MEMBERSHIP,
 };
+#[cfg(all(feature = "all", any(target_os = "linux", target_os = "illumos")))]
+pub(crate) use libc::{IPV6_MINHOPCOUNT, IP_MINTTL};
 #[cfg(not(target_os = "wasi"))]
 pub(crate) use libc::{IPV6_MULTICAST_HOPS, IPV6_MULTICAST_IF, IP_MULTICAST_IF, MSG_OOB};
 #[cfg(all(

tests/socket.rs

@@ -1519,6 +1519,9 @@ test!(IPv6 freebind_v6, set_freebind_v6(true));
 
 test!(IPv4 ttl_v4, set_ttl_v4(40));
 
+#[cfg(all(feature = "all", any(target_os = "linux", target_os = "illumos")))]
+test!(IPv4 min_ttl_v4, set_min_ttl_v4(50));
+
 #[cfg(not(any(
     target_os = "fuchsia",
     target_os = "redox",
@@ -1552,6 +1555,9 @@ test!(IPv4 broadcast, set_broadcast(true));
 #[cfg(not(target_os = "vita"))]
 test!(IPv6 unicast_hops_v6, set_unicast_hops_v6(20));
 
+#[cfg(all(feature = "all", any(target_os = "linux", target_os = "illumos")))]
+test!(IPv6 min_hopcount_v6, set_min_hopcount_v6(30));
+
 #[cfg(not(any(
     windows,
     target_os = "dragonfly",
@@ -1970,3 +1976,27 @@ fn set_busy_poll() {
         assert!(socket.busy_poll().unwrap() == i);
     }
 }
+
+#[cfg(all(feature = "all", any(target_os = "linux", target_os = "illumos")))]
+#[test]
+fn min_ttl_v4_preserves_outbound_ttl() {
+    let socket = Socket::new(Domain::IPV4, Type::STREAM, None).unwrap();
+
+    socket.set_ttl_v4(61).unwrap();
+    socket.set_min_ttl_v4(197).unwrap();
+
+    assert_eq!(socket.min_ttl_v4().unwrap(), 197);
+    assert_eq!(socket.ttl_v4().unwrap(), 61);
+}
+
+#[cfg(all(feature = "all", any(target_os = "linux", target_os = "illumos")))]
+#[test]
+fn min_hopcount_v6_preserves_outbound_hops() {
+    let socket = Socket::new(Domain::IPV6, Type::STREAM, None).unwrap();
+
+    socket.set_unicast_hops_v6(61).unwrap();
+    socket.set_min_hopcount_v6(197).unwrap();
+
+    assert_eq!(socket.min_hopcount_v6().unwrap(), 197);
+    assert_eq!(socket.unicast_hops_v6().unwrap(), 61);
+}