std::net: adding acceptfilter feature for netbsd/freebsd.

similar to linux's ext deferaccept, to filter incoming connections
before accept.

library/std/src/os/freebsd/net.rs

@@ -2,6 +2,7 @@
 
 #![unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
 
+use crate::ffi::CStr;
 use crate::io;
 use crate::os::unix::net;
 use crate::sealed::Sealed;
@@ -40,6 +41,15 @@ pub trait UnixSocketExt: Sealed {
  /// ```
  #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
  fn set_local_creds_persistent(&self, local_creds_persistent: bool) -> io::Result<()>;
+
+ /// Get a filter name if one had been set previously on the socket.
+ #[unstable(feature = "acceptfilter", issue = "121891")]
+ fn acceptfilter(&self) -> io::Result<&CStr>;
+
+ /// Set or disable a filter on the socket to filter incoming connections
+ /// to defer it before accept(2)
+ #[unstable(feature = "acceptfilter", issue = "121891")]
+ fn set_acceptfilter(&self, name: &CStr) -> io::Result<()>;
 }
 
 #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
@@ -51,6 +61,14 @@ impl UnixSocketExt for net::UnixDatagram {
  fn set_local_creds_persistent(&self, local_creds_persistent: bool) -> io::Result<()> {
  self.as_inner().set_local_creds_persistent(local_creds_persistent)
  }
+
+ fn acceptfilter(&self) -> io::Result<&CStr> {
+ self.as_inner().acceptfilter()
+ }
+
+ fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+ self.as_inner().set_acceptfilter(name)
+ }
 }
 
 #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
@@ -62,4 +80,12 @@ impl UnixSocketExt for net::UnixStream {
  fn set_local_creds_persistent(&self, local_creds_persistent: bool) -> io::Result<()> {
  self.as_inner().set_local_creds_persistent(local_creds_persistent)
  }
+
+ fn acceptfilter(&self) -> io::Result<&CStr> {
+ self.as_inner().acceptfilter()
+ }
+
+ fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+ self.as_inner().set_acceptfilter(name)
+ }
 }

library/std/src/os/netbsd/net.rs

@@ -2,6 +2,7 @@
 
 #![unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
 
+use crate::ffi::CStr;
 use crate::io;
 use crate::os::unix::net;
 use crate::sealed::Sealed;
@@ -40,6 +41,15 @@ pub trait UnixSocketExt: Sealed {
  /// ```
  #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
  fn set_local_creds(&self, local_creds: bool) -> io::Result<()>;
+
+ /// Get a filter name if one had been set previously on the socket.
+ #[unstable(feature = "acceptfilter", issue = "121891")]
+ fn acceptfilter(&self) -> io::Result<&CStr>;
+
+ /// Set or disable a filter on the socket to filter incoming connections
+ /// to defer it before accept(2)
+ #[unstable(feature = "acceptfilter", issue = "121891")]
+ fn set_acceptfilter(&self, name: &CStr) -> io::Result<()>;
 }
 
 #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
@@ -51,6 +61,14 @@ impl UnixSocketExt for net::UnixDatagram {
  fn set_local_creds(&self, local_creds: bool) -> io::Result<()> {
  self.as_inner().set_local_creds(local_creds)
  }
+
+ fn acceptfilter(&self) -> io::Result<&CStr> {
+ self.as_inner().acceptfilter()
+ }
+
+ fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+ self.as_inner().set_acceptfilter(name)
+ }
 }
 
 #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
@@ -62,4 +80,12 @@ impl UnixSocketExt for net::UnixStream {
  fn set_local_creds(&self, local_creds: bool) -> io::Result<()> {
  self.as_inner().set_local_creds(local_creds)
  }
+
+ fn acceptfilter(&self) -> io::Result<&CStr> {
+ self.as_inner().acceptfilter()
+ }
+
+ fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+ self.as_inner().set_acceptfilter(name)
+ }
 }

library/std/src/sys/pal/unix/net.rs

@@ -453,6 +453,37 @@ impl Socket {
  Ok(raw as u32)
  }
 
+ #[cfg(any(target_os = "freebsd", target_os = "netbsd"))]
+ pub fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+ if !name.to_bytes().is_empty() {
+ const AF_NAME_MAX: usize = 16;
+ let mut buf = [0; AF_NAME_MAX];
+ for (src, dst) in name.to_bytes().iter().zip(&mut buf[..AF_NAME_MAX - 1]) {
+ *dst = *src as i8;
+ }
+ let mut arg: libc::accept_filter_arg = unsafe { mem::zeroed() };
+ arg.af_name = buf;
+ setsockopt(self, libc::SOL_SOCKET, libc::SO_ACCEPTFILTER, &mut arg)
+ } else {
+ setsockopt(
+ self,
+ libc::SOL_SOCKET,
+ libc::SO_ACCEPTFILTER,
+ core::ptr::null_mut() as *mut c_void,
+ )
+ }
+ }
+
+ #[cfg(any(target_os = "freebsd", target_os = "netbsd"))]
+ pub fn acceptfilter(&self) -> io::Result<&CStr> {
+ let arg: libc::accept_filter_arg =
+ getsockopt(self, libc::SOL_SOCKET, libc::SO_ACCEPTFILTER)?;
+ let s: &[u8] =
+ unsafe { core::slice::from_raw_parts(arg.af_name.as_ptr() as *const u8, 16) };
+ let name = CStr::from_bytes_with_nul(s).unwrap();
+ Ok(name)
+ }
+
  #[cfg(any(target_os = "android", target_os = "linux",))]
  pub fn set_passcred(&self, passcred: bool) -> io::Result<()> {
  setsockopt(self, libc::SOL_SOCKET, libc::SO_PASSCRED, passcred as libc::c_int)