For invalid IP address conversions with future Rust versions

Rust's standard library no longer guarantees that Ipv4Addr and Ipv6Addr
are wrappers around the C types (though for now at least, they are
identical on all platforms I'm aware of).  So do the conversions
explicitly instead of transmuting.

Fixes #2053

1 files changed, 6 insertions, 10 deletions

diff --git a/src/sys/socket/addr.rs b/src/sys/socket/addr.rs
index 48309749..2b3a1ed4 100644
--- a/src/sys/socket/addr.rs
+++ b/src/sys/socket/addr.rs
@@ -39,18 +39,17 @@ use std::{fmt, mem, net, ptr, slice};
 /// Convert a std::net::Ipv4Addr into the libc form.
 #[cfg(feature = "net")]
 pub(crate) const fn ipv4addr_to_libc(addr: net::Ipv4Addr) -> libc::in_addr {
-    static_assertions::assert_eq_size!(net::Ipv4Addr, libc::in_addr);
-    // Safe because both types have the same memory layout, and no fancy Drop
-    // impls.
-    unsafe { mem::transmute(addr) }
+    libc::in_addr {
+        s_addr: u32::from_ne_bytes(addr.octets())
+    }
 }
 
 /// Convert a std::net::Ipv6Addr into the libc form.
 #[cfg(feature = "net")]
 pub(crate) const fn ipv6addr_to_libc(addr: &net::Ipv6Addr) -> libc::in6_addr {
-    static_assertions::assert_eq_size!(net::Ipv6Addr, libc::in6_addr);
-    // Safe because both are Newtype wrappers around the same libc type
-    unsafe { mem::transmute(*addr) }
+    libc::in6_addr {
+        s6_addr: addr.octets()
+    }
 }
 
 /// These constants specify the protocol family to be used
@@ -949,9 +948,6 @@ impl SockaddrLike for () {
 }
 
 /// An IPv4 socket address
-// This is identical to net::SocketAddrV4.  But the standard library
-// doesn't allow direct access to the libc fields, which we need.  So we
-// reimplement it here.
 #[cfg(feature = "net")]
 #[repr(transparent)]
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]