Add trait to reduce duplicated code between socket address types, implement netlink addresses (#1004)

* Add SocketAddrArg trait to reduce code duplicated across address types

* Move `SocketAddrStorage` to `crate::net::addr`

* Replace SocketAddrAny enum with a safe wrapper for SocketAddrStorage

To support extensibility over address types, use sockaddr_storage and
Into / TryInto conversions.

* Remove address type variants of `bind`, `connect`, `sendmsg`, `sendto`

Removes:
* `bind_any`, `bind_unix`, `bind_v4`, `bind_v6`, `bind_xdp` in favor of `bind`,
* `connect_any`, `connect_unix`, `connect_v4`, `connect_v6` in favor of `connect` (leaving address-less `connect_unspec`)
* `sendmsg_v4`, `sendmsg_v6`, `sendmsg_unix`, `sendmsg_xdp`, `sendmsg_any` in favor of `sendmsg_addr` (leaving address-less `sendmsg`)
* `sendto_any`, `sendto_v4`, `sendto_v6`, `sendto_unix`, `sendto_xdp` in favor of `sendto`

* Add support for Netlink socket addresses

* Introduce a `SocketAddrLen` type and use it for `SocketAddrOpaque` sizes.

* Fix `bind(&s, &"127.0.0.1:0".parse().unwrap())` in tests.

---------

Co-authored-by: Dan Gohman <dev@sunfishcode.online>

Author: kevinmehall

src/backend/libc/net/addr.rs

@@ -8,6 +8,7 @@ use core::slice;
 use {
     crate::ffi::CStr,
     crate::io,
+    crate::net::addr::SocketAddrLen,
     crate::path,
     core::cmp::Ordering,
     core::fmt,
@@ -151,14 +152,14 @@ impl SocketAddrUnix {
     }
 
     #[inline]
-    pub(crate) fn addr_len(&self) -> c::socklen_t {
+    pub(crate) fn addr_len(&self) -> SocketAddrLen {
         #[cfg(not(any(bsd, target_os = "haiku")))]
         {
-            self.len
+            self.len as _
         }
         #[cfg(any(bsd, target_os = "haiku"))]
         {
-            c::socklen_t::from(self.unix.sun_len)
+            c::socklen_t::from(self.unix.sun_len) as _
         }
     }
 
@@ -169,7 +170,7 @@ impl SocketAddrUnix {
 
     #[inline]
     fn bytes(&self) -> Option<&[u8]> {
-        let len = self.len() as usize;
+        let len = self.len();
         if len != 0 {
             let bytes = &self.unix.sun_path[..len - offsetof_sun_path()];
             // SAFETY: `from_raw_parts` to convert from `&[c_char]` to `&[u8]`.
@@ -238,6 +239,7 @@ impl fmt::Debug for SocketAddrUnix {
 
 /// `struct sockaddr_storage`.
 #[repr(transparent)]
+#[derive(Copy, Clone)]
 pub struct SocketAddrStorage(c::sockaddr_storage);
 
 impl SocketAddrStorage {

src/backend/libc/net/msghdr.rs

@@ -5,32 +5,26 @@
 
 use crate::backend::c;
 use crate::backend::conv::{msg_control_len, msg_iov_len};
-#[cfg(target_os = "linux")]
-use crate::backend::net::write_sockaddr::encode_sockaddr_xdp;
-use crate::backend::net::write_sockaddr::{encode_sockaddr_v4, encode_sockaddr_v6};
 
 use crate::io::{self, IoSlice, IoSliceMut};
-#[cfg(target_os = "linux")]
-use crate::net::xdp::SocketAddrXdp;
-use crate::net::{RecvAncillaryBuffer, SendAncillaryBuffer, SocketAddrV4, SocketAddrV6};
-use crate::utils::as_ptr;
+use crate::net::SocketAddrBuf;
+use crate::net::{addr::SocketAddrArg, RecvAncillaryBuffer, SendAncillaryBuffer};
 
-use core::mem::{size_of, zeroed, MaybeUninit};
+use core::mem::zeroed;
 
 /// Create a message header intended to receive a datagram.
 pub(crate) fn with_recv_msghdr<R>(
-    name: &mut MaybeUninit<c::sockaddr_storage>,
+    name: &mut SocketAddrBuf,
     iov: &mut [IoSliceMut<'_>],
     control: &mut RecvAncillaryBuffer<'_>,
     f: impl FnOnce(&mut c::msghdr) -> io::Result<R>,
 ) -> io::Result<R> {
     control.clear();
 
-    let namelen = size_of::<c::sockaddr_storage>() as c::socklen_t;
     let mut msghdr = {
         let mut h = zero_msghdr();
-        h.msg_name = name.as_mut_ptr().cast();
-        h.msg_namelen = namelen;
+        h.msg_name = name.storage.as_mut_ptr().cast();
+        h.msg_namelen = name.len;
         h.msg_iov = iov.as_mut_ptr().cast();
         h.msg_iovlen = msg_iov_len(iov.len());
         h.msg_control = control.as_control_ptr().cast();
@@ -47,6 +41,8 @@ pub(crate) fn with_recv_msghdr<R>(
         }
     }
 
+    name.len = msghdr.msg_namelen;
+
     res
 }
 
@@ -66,87 +62,24 @@ pub(crate) fn with_noaddr_msghdr<R>(
     })
 }
 
-/// Create a message header intended to send with an IPv4 address.
-pub(crate) fn with_v4_msghdr<R>(
-    addr: &SocketAddrV4,
-    iov: &[IoSlice<'_>],
-    control: &mut SendAncillaryBuffer<'_, '_, '_>,
-    f: impl FnOnce(c::msghdr) -> R,
-) -> R {
-    let encoded = encode_sockaddr_v4(addr);
-
-    f({
-        let mut h = zero_msghdr();
-        h.msg_name = as_ptr(&encoded) as _;
-        h.msg_namelen = size_of::<SocketAddrV4>() as _;
-        h.msg_iov = iov.as_ptr() as _;
-        h.msg_iovlen = msg_iov_len(iov.len());
-        h.msg_control = control.as_control_ptr().cast();
-        h.msg_controllen = msg_control_len(control.control_len());
-        h
-    })
-}
-
-/// Create a message header intended to send with an IPv6 address.
-pub(crate) fn with_v6_msghdr<R>(
-    addr: &SocketAddrV6,
-    iov: &[IoSlice<'_>],
-    control: &mut SendAncillaryBuffer<'_, '_, '_>,
-    f: impl FnOnce(c::msghdr) -> R,
-) -> R {
-    let encoded = encode_sockaddr_v6(addr);
-
-    f({
-        let mut h = zero_msghdr();
-        h.msg_name = as_ptr(&encoded) as _;
-        h.msg_namelen = size_of::<SocketAddrV6>() as _;
-        h.msg_iov = iov.as_ptr() as _;
-        h.msg_iovlen = msg_iov_len(iov.len());
-        h.msg_control = control.as_control_ptr().cast();
-        h.msg_controllen = msg_control_len(control.control_len());
-        h
-    })
-}
-
-/// Create a message header intended to send with a Unix address.
-#[cfg(all(unix, not(target_os = "redox")))]
-pub(crate) fn with_unix_msghdr<R>(
-    addr: &crate::net::SocketAddrUnix,
+/// Create a message header intended to send with the specified address.
+pub(crate) fn with_msghdr<R>(
+    addr: &impl SocketAddrArg,
     iov: &[IoSlice<'_>],
     control: &mut SendAncillaryBuffer<'_, '_, '_>,
     f: impl FnOnce(c::msghdr) -> R,
 ) -> R {
-    f({
-        let mut h = zero_msghdr();
-        h.msg_name = as_ptr(&addr.unix) as _;
-        h.msg_namelen = addr.addr_len();
-        h.msg_iov = iov.as_ptr() as _;
-        h.msg_iovlen = msg_iov_len(iov.len());
-        h.msg_control = control.as_control_ptr().cast();
-        h.msg_controllen = msg_control_len(control.control_len());
-        h
-    })
-}
-
-/// Create a message header intended to send with an IPv6 address.
-#[cfg(target_os = "linux")]
-pub(crate) fn with_xdp_msghdr<R>(
-    addr: &SocketAddrXdp,
-    iov: &[IoSlice<'_>],
-    control: &mut SendAncillaryBuffer<'_, '_, '_>,
-    f: impl FnOnce(c::msghdr) -> R,
-) -> R {
-    let encoded = encode_sockaddr_xdp(addr);
-
-    f({
-        let mut h = zero_msghdr();
-        h.msg_name = as_ptr(&encoded) as _;
-        h.msg_namelen = size_of::<SocketAddrXdp>() as _;
-        h.msg_iov = iov.as_ptr() as _;
-        h.msg_iovlen = msg_iov_len(iov.len());
-        h.msg_control = control.as_control_ptr().cast();
-        h.msg_controllen = msg_control_len(control.control_len());
-        h
+    addr.with_sockaddr(|addr_ptr, addr_len| {
+        f({
+            let mut h = zero_msghdr();
+            h.msg_name = addr_ptr as *mut _;
+            h.msg_namelen = addr_len as _;
+            h.msg_iov = iov.as_ptr() as _;
+            h.msg_iovlen = msg_iov_len(iov.len());
+            h.msg_control = control.as_control_ptr().cast();
+            h.msg_controllen = msg_control_len(control.control_len());
+            h
+        })
     })
 }