src/lib.rs - platform/external/rust/crates/vsock - Gitiles

 /*
  * Copyright 2019 fsyncd, Berlin, Germany.
  * Additional material Copyright the Rust project and it's contributors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 //! Virtio socket support for Rust.

 use libc::*;
 use nix::ioctl_read_bad;
 use std::ffi::c_void;
 use std::fs::File;
 use std::io::{Error, ErrorKind, Read, Result, Write};
 use std::mem::{self, size_of};
 use std::net::Shutdown;
 use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
 use std::time::Duration;

 pub use libc::{VMADDR_CID_ANY, VMADDR_CID_HOST, VMADDR_CID_HYPERVISOR, VMADDR_CID_LOCAL};
 pub use nix::sys::socket::{SockAddr, VsockAddr};

 fn new_socket() -> libc::c_int {
     unsafe { socket(AF_VSOCK, SOCK_STREAM | SOCK_CLOEXEC, 0) }
 }

 /// An iterator that infinitely accepts connections on a VsockListener.
 #[derive(Debug)]
 pub struct Incoming<'a> {
     listener: &'a VsockListener,
 }

 impl<'a> Iterator for Incoming<'a> {
     type Item = Result<VsockStream>;

     fn next(&mut self) -> Option<Result<VsockStream>> {
         Some(self.listener.accept().map(|p| p.0))
     }
 }

 /// A virtio socket server, listening for connections.
 #[derive(Debug, Clone)]
 pub struct VsockListener {
     socket: RawFd,
 }

 impl VsockListener {
     /// Create a new VsockListener which is bound and listening on the socket address.
     pub fn bind(addr: &SockAddr) -> Result<VsockListener> {
         let mut vsock_addr = if let SockAddr::Vsock(addr) = addr {
             addr.0
         } else {
             return Err(Error::new(
                 ErrorKind::Other,
                 "requires a virtio socket address",
             ));
         };

         let socket = new_socket();
         if socket < 0 {
             return Err(Error::last_os_error());
         }

         let res = unsafe {
             bind(
                 socket,
                 &mut vsock_addr as *mut _ as *mut sockaddr,
                 size_of::<sockaddr_vm>() as socklen_t,
             )
         };
         if res < 0 {
             return Err(Error::last_os_error());
         }

         // rust stdlib uses a 128 connection backlog
         let res = unsafe { listen(socket, 128) };
         if res < 0 {
             return Err(Error::last_os_error());
         }

         Ok(Self { socket })
     }

     /// Create a new VsockListener with specified cid and port.
     pub fn bind_with_cid_port(cid: u32, port: u32) -> Result<VsockListener> {
         Self::bind(&SockAddr::Vsock(VsockAddr::new(cid, port)))
     }

     /// The local socket address of the listener.
     pub fn local_addr(&self) -> Result<SockAddr> {
         let mut vsock_addr = sockaddr_vm {
             svm_family: AF_VSOCK as sa_family_t,
             svm_reserved1: 0,
             svm_port: 0,
             svm_cid: 0,
             svm_zero: [0u8; 4],
         };
         let mut vsock_addr_len = size_of::<sockaddr_vm>() as socklen_t;
         if unsafe {
             getsockname(
                 self.socket,
                 &mut vsock_addr as *mut _ as *mut sockaddr,
                 &mut vsock_addr_len,
             )
         } < 0
         {
             Err(Error::last_os_error())
         } else {
             Ok(SockAddr::Vsock(VsockAddr(vsock_addr)))
         }
     }

     /// Create a new independently owned handle to the underlying socket.
     pub fn try_clone(&self) -> Result<Self> {
         Ok(self.clone())
     }

     /// Accept a new incoming connection from this listener.
     pub fn accept(&self) -> Result<(VsockStream, SockAddr)> {
         let mut vsock_addr = sockaddr_vm {
             svm_family: AF_VSOCK as sa_family_t,
             svm_reserved1: 0,
             svm_port: 0,
             svm_cid: 0,
             svm_zero: [0u8; 4],
         };
         let mut vsock_addr_len = size_of::<sockaddr_vm>() as socklen_t;
         let socket = unsafe {
             accept4(
                 self.socket,
                 &mut vsock_addr as *mut _ as *mut sockaddr,
                 &mut vsock_addr_len,
                 SOCK_CLOEXEC,
             )
         };
         if socket < 0 {
             Err(Error::last_os_error())
         } else {
             Ok((
                 unsafe { VsockStream::from_raw_fd(socket as RawFd) },
                 SockAddr::Vsock(VsockAddr::new(vsock_addr.svm_cid, vsock_addr.svm_port)),
             ))
         }
     }

     /// An iterator over the connections being received on this listener.
     pub fn incoming(&self) -> Incoming {
         Incoming { listener: self }
     }

     /// Retrieve the latest error associated with the underlying socket.
     pub fn take_error(&self) -> Result<Option<Error>> {
         let mut error: i32 = 0;
         let mut error_len: socklen_t = 0;
         if unsafe {
             getsockopt(
                 self.socket,
                 SOL_SOCKET,
                 SO_ERROR,
                 &mut error as *mut _ as *mut c_void,
                 &mut error_len,
             )
         } < 0
         {
             Err(Error::last_os_error())
         } else {
             Ok(if error == 0 {
                 None
             } else {
                 Some(Error::from_raw_os_error(error))
             })
         }
     }

     /// Move this stream in and out of nonblocking mode.
     pub fn set_nonblocking(&self, nonblocking: bool) -> Result<()> {
         let mut nonblocking: i32 = if nonblocking { 1 } else { 0 };
         if unsafe { ioctl(self.socket, FIONBIO, &mut nonblocking) } < 0 {
             Err(Error::last_os_error())
         } else {
             Ok(())
         }
     }
 }

 impl AsRawFd for VsockListener {
     fn as_raw_fd(&self) -> RawFd {
         self.socket
     }
 }

 impl FromRawFd for VsockListener {
     unsafe fn from_raw_fd(socket: RawFd) -> Self {
         Self { socket }
     }
 }

 impl IntoRawFd for VsockListener {
     fn into_raw_fd(self) -> RawFd {
         let fd = self.socket;
         mem::forget(self);
         fd
     }
 }

 impl Drop for VsockListener {
     fn drop(&mut self) {
         unsafe { close(self.socket) };
     }
 }

 /// A virtio stream between a local and a remote socket.
 #[derive(Debug, Clone)]
 pub struct VsockStream {
     socket: RawFd,
 }

 impl VsockStream {
     /// Open a connection to a remote host.
     pub fn connect(addr: &SockAddr) -> Result<Self> {
         let vsock_addr = if let SockAddr::Vsock(addr) = addr {
             addr.0
         } else {
             return Err(Error::new(
                 ErrorKind::Other,
                 "requires a virtio socket address",
             ));
         };

         let sock = new_socket();
         if sock < 0 {
             return Err(Error::last_os_error());
         }
         if unsafe {
             connect(
                 sock,
                 &vsock_addr as *const _ as *const sockaddr,
                 size_of::<sockaddr_vm>() as socklen_t,
             )
         } < 0
         {
             Err(Error::last_os_error())
         } else {
             Ok(unsafe { VsockStream::from_raw_fd(sock) })
         }
     }

     /// Open a connection to a remote host with specified cid and port.
     pub fn connect_with_cid_port(cid: u32, port: u32) -> Result<Self> {
         Self::connect(&SockAddr::Vsock(VsockAddr::new(cid, port)))
     }

     /// Virtio socket address of the remote peer associated with this connection.
     pub fn peer_addr(&self) -> Result<SockAddr> {
         let mut vsock_addr = sockaddr_vm {
             svm_family: AF_VSOCK as sa_family_t,
             svm_reserved1: 0,
             svm_port: 0,
             svm_cid: 0,
             svm_zero: [0u8; 4],
         };
         let mut vsock_addr_len = size_of::<sockaddr_vm>() as socklen_t;
         if unsafe {
             getpeername(
                 self.socket,
                 &mut vsock_addr as *mut _ as *mut sockaddr,
                 &mut vsock_addr_len,
             )
         } < 0
         {
             Err(Error::last_os_error())
         } else {
             Ok(SockAddr::Vsock(VsockAddr(vsock_addr)))
         }
     }

     /// Virtio socket address of the local address associated with this connection.
     pub fn local_addr(&self) -> Result<SockAddr> {
         let mut vsock_addr = sockaddr_vm {
             svm_family: AF_VSOCK as sa_family_t,
             svm_reserved1: 0,
             svm_port: 0,
             svm_cid: 0,
             svm_zero: [0u8; 4],
         };
         let mut vsock_addr_len = size_of::<sockaddr_vm>() as socklen_t;
         if unsafe {
             getsockname(
                 self.socket,
                 &mut vsock_addr as *mut _ as *mut sockaddr,
                 &mut vsock_addr_len,
             )
         } < 0
         {
             Err(Error::last_os_error())
         } else {
             Ok(SockAddr::Vsock(VsockAddr(vsock_addr)))
         }
     }

     /// Shutdown the read, write, or both halves of this connection.
     pub fn shutdown(&self, how: Shutdown) -> Result<()> {
         let how = match how {
             Shutdown::Write => SHUT_WR,
             Shutdown::Read => SHUT_RD,
             Shutdown::Both => SHUT_RDWR,
         };
         if unsafe { shutdown(self.socket, how) } < 0 {
             Err(Error::last_os_error())
         } else {
             Ok(())
         }
     }

     /// Create a new independently owned handle to the underlying socket.
     pub fn try_clone(&self) -> Result<Self> {
         Ok(self.clone())
     }

     /// Set the timeout on read operations.
     pub fn set_read_timeout(&self, dur: Option<Duration>) -> Result<()> {
         let timeout = Self::timeval_from_duration(dur)?;
         if unsafe {
             setsockopt(
                 self.socket,
                 SOL_SOCKET,
                 SO_SNDTIMEO,
                 &timeout as *const _ as *const c_void,
                 size_of::<timeval>() as socklen_t,
             )
         } < 0
         {
             Err(Error::last_os_error())
         } else {
             Ok(())
         }
     }

     /// Set the timeout on write operations.
     pub fn set_write_timeout(&self, dur: Option<Duration>) -> Result<()> {
         let timeout = Self::timeval_from_duration(dur)?;
         if unsafe {
             setsockopt(
                 self.socket,
                 SOL_SOCKET,
                 SO_RCVTIMEO,
                 &timeout as *const _ as *const c_void,
                 size_of::<timeval>() as socklen_t,
             )
         } < 0
         {
             Err(Error::last_os_error())
         } else {
             Ok(())
         }
     }

     /// Retrieve the latest error associated with the underlying socket.
     pub fn take_error(&self) -> Result<Option<Error>> {
         let mut error: i32 = 0;
         let mut error_len: socklen_t = 0;
         if unsafe {
             getsockopt(
                 self.socket,
                 SOL_SOCKET,
                 SO_ERROR,
                 &mut error as *mut _ as *mut c_void,
                 &mut error_len,
             )
         } < 0
         {
             Err(Error::last_os_error())
         } else {
             Ok(if error == 0 {
                 None
             } else {
                 Some(Error::from_raw_os_error(error))
             })
         }
     }

     /// Move this stream in and out of nonblocking mode.
     pub fn set_nonblocking(&self, nonblocking: bool) -> Result<()> {
         let mut nonblocking: i32 = if nonblocking { 1 } else { 0 };
         if unsafe { ioctl(self.socket, FIONBIO, &mut nonblocking) } < 0 {
             Err(Error::last_os_error())
         } else {
             Ok(())
         }
     }

     fn timeval_from_duration(dur: Option<Duration>) -> Result<timeval> {
         match dur {
             Some(dur) => {
                 if dur.as_secs() == 0 && dur.subsec_nanos() == 0 {
                     return Err(Error::new(
                         ErrorKind::InvalidInput,
                         "cannot set a zero duration timeout",
                     ));
                 }

                 // https://github.com/rust-lang/libc/issues/1848
                 #[cfg_attr(target_env = "musl", allow(deprecated))]
                 let secs = if dur.as_secs() > time_t::max_value() as u64 {
                     time_t::max_value()
                 } else {
                     dur.as_secs() as time_t
                 };
                 let mut timeout = timeval {
                     tv_sec: secs,
                     tv_usec: i64::from(dur.subsec_micros()) as suseconds_t,
                 };
                 if timeout.tv_sec == 0 && timeout.tv_usec == 0 {
                     timeout.tv_usec = 1;
                 }
                 Ok(timeout)
             }
             None => Ok(timeval {
                 tv_sec: 0,
                 tv_usec: 0,
             }),
         }
     }
 }

 impl Read for VsockStream {
     fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
         <&Self>::read(&mut &*self, buf)
     }
 }

 impl Write for VsockStream {
     fn write(&mut self, buf: &[u8]) -> Result<usize> {
         <&Self>::write(&mut &*self, buf)
     }

     fn flush(&mut self) -> Result<()> {
         Ok(())
     }
 }

 impl Read for &VsockStream {
     fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
         let ret = unsafe { recv(self.socket, buf.as_mut_ptr() as *mut c_void, buf.len(), 0) };
         if ret < 0 {
             Err(Error::last_os_error())
         } else {
             Ok(ret as usize)
         }
     }
 }

 impl Write for &VsockStream {
     fn write(&mut self, buf: &[u8]) -> Result<usize> {
         let ret = unsafe {
             send(
                 self.socket,
                 buf.as_ptr() as *const c_void,
                 buf.len(),
                 MSG_NOSIGNAL,
             )
         };
         if ret < 0 {
             Err(Error::last_os_error())
         } else {
             Ok(ret as usize)
         }
     }

     fn flush(&mut self) -> Result<()> {
         Ok(())
     }
 }

 impl AsRawFd for VsockStream {
     fn as_raw_fd(&self) -> RawFd {
         self.socket
     }
 }

 impl FromRawFd for VsockStream {
     unsafe fn from_raw_fd(socket: RawFd) -> Self {
         Self { socket }
     }
 }

 impl IntoRawFd for VsockStream {
     fn into_raw_fd(self) -> RawFd {
         let fd = self.socket;
         mem::forget(self);
         fd
     }
 }

 impl Drop for VsockStream {
     fn drop(&mut self) {
         unsafe { close(self.socket) };
     }
 }

 const IOCTL_VM_SOCKETS_GET_LOCAL_CID: usize = 0x7b9;
 ioctl_read_bad!(
     vm_sockets_get_local_cid,
     IOCTL_VM_SOCKETS_GET_LOCAL_CID,
     u32
 );

 /// Gets the CID of the local machine.
 ///
 /// Note that when calling [`VsockListener::bind`], you should generally use [`VMADDR_CID_ANY`]
 /// instead, and for making a loopback connection you should use [`VMADDR_CID_LOCAL`].
 pub fn get_local_cid() -> Result<u32> {
     let f = File::open("/dev/vsock")?;
     let mut cid = 0;
     // SAFETY: the kernel only modifies the given u32 integer.
     unsafe { vm_sockets_get_local_cid(f.as_raw_fd(), &mut cid) }?;
     Ok(cid)
 }
	/*
	* Copyright 2019 fsyncd, Berlin, Germany.
	* Additional material Copyright the Rust project and it's contributors.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	//! Virtio socket support for Rust.

	use libc::*;
	use nix::ioctl_read_bad;
	use std::ffi::c_void;
	use std::fs::File;
	use std::io::{Error, ErrorKind, Read, Result, Write};
	use std::mem::{self, size_of};
	use std::net::Shutdown;
	use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
	use std::time::Duration;

	pub use libc::{VMADDR_CID_ANY, VMADDR_CID_HOST, VMADDR_CID_HYPERVISOR, VMADDR_CID_LOCAL};
	pub use nix::sys::socket::{SockAddr, VsockAddr};

	fn new_socket() -> libc::c_int {
	unsafe { socket(AF_VSOCK, SOCK_STREAM \| SOCK_CLOEXEC, 0) }
	}

	/// An iterator that infinitely accepts connections on a VsockListener.
	#[derive(Debug)]
	pub struct Incoming<'a> {
	listener: &'a VsockListener,
	}

	impl<'a> Iterator for Incoming<'a> {
	type Item = Result<VsockStream>;

	fn next(&mut self) -> Option<Result<VsockStream>> {
	Some(self.listener.accept().map(\|p\| p.0))
	}
	}

	/// A virtio socket server, listening for connections.
	#[derive(Debug, Clone)]
	pub struct VsockListener {
	socket: RawFd,
	}

	impl VsockListener {
	/// Create a new VsockListener which is bound and listening on the socket address.
	pub fn bind(addr: &SockAddr) -> Result<VsockListener> {
	let mut vsock_addr = if let SockAddr::Vsock(addr) = addr {
	addr.0
	} else {
	return Err(Error::new(
	ErrorKind::Other,
	"requires a virtio socket address",
	));
	};

	let socket = new_socket();
	if socket < 0 {
	return Err(Error::last_os_error());
	}

	let res = unsafe {
	bind(
	socket,
	&mut vsock_addr as mut _ as mut sockaddr,
	size_of::<sockaddr_vm>() as socklen_t,
	)
	};
	if res < 0 {
	return Err(Error::last_os_error());
	}

	// rust stdlib uses a 128 connection backlog
	let res = unsafe { listen(socket, 128) };
	if res < 0 {
	return Err(Error::last_os_error());
	}

	Ok(Self { socket })
	}

	/// Create a new VsockListener with specified cid and port.
	pub fn bind_with_cid_port(cid: u32, port: u32) -> Result<VsockListener> {
	Self::bind(&SockAddr::Vsock(VsockAddr::new(cid, port)))
	}

	/// The local socket address of the listener.
	pub fn local_addr(&self) -> Result<SockAddr> {
	let mut vsock_addr = sockaddr_vm {
	svm_family: AF_VSOCK as sa_family_t,
	svm_reserved1: 0,
	svm_port: 0,
	svm_cid: 0,
	svm_zero: [0u8; 4],
	};
	let mut vsock_addr_len = size_of::<sockaddr_vm>() as socklen_t;
	if unsafe {
	getsockname(
	self.socket,
	&mut vsock_addr as mut _ as mut sockaddr,
	&mut vsock_addr_len,
	)
	} < 0
	{
	Err(Error::last_os_error())
	} else {
	Ok(SockAddr::Vsock(VsockAddr(vsock_addr)))
	}
	}

	/// Create a new independently owned handle to the underlying socket.
	pub fn try_clone(&self) -> Result<Self> {
	Ok(self.clone())
	}

	/// Accept a new incoming connection from this listener.
	pub fn accept(&self) -> Result<(VsockStream, SockAddr)> {
	let mut vsock_addr = sockaddr_vm {
	svm_family: AF_VSOCK as sa_family_t,
	svm_reserved1: 0,
	svm_port: 0,
	svm_cid: 0,
	svm_zero: [0u8; 4],
	};
	let mut vsock_addr_len = size_of::<sockaddr_vm>() as socklen_t;
	let socket = unsafe {
	accept4(
	self.socket,
	&mut vsock_addr as mut _ as mut sockaddr,
	&mut vsock_addr_len,
	SOCK_CLOEXEC,
	)
	};
	if socket < 0 {
	Err(Error::last_os_error())
	} else {
	Ok((
	unsafe { VsockStream::from_raw_fd(socket as RawFd) },
	SockAddr::Vsock(VsockAddr::new(vsock_addr.svm_cid, vsock_addr.svm_port)),
	))
	}
	}

	/// An iterator over the connections being received on this listener.
	pub fn incoming(&self) -> Incoming {
	Incoming { listener: self }
	}

	/// Retrieve the latest error associated with the underlying socket.
	pub fn take_error(&self) -> Result<Option<Error>> {
	let mut error: i32 = 0;
	let mut error_len: socklen_t = 0;
	if unsafe {
	getsockopt(
	self.socket,
	SOL_SOCKET,
	SO_ERROR,
	&mut error as mut _ as mut c_void,
	&mut error_len,
	)
	} < 0
	{
	Err(Error::last_os_error())
	} else {
	Ok(if error == 0 {
	None
	} else {
	Some(Error::from_raw_os_error(error))
	})
	}
	}

	/// Move this stream in and out of nonblocking mode.
	pub fn set_nonblocking(&self, nonblocking: bool) -> Result<()> {
	let mut nonblocking: i32 = if nonblocking { 1 } else { 0 };
	if unsafe { ioctl(self.socket, FIONBIO, &mut nonblocking) } < 0 {
	Err(Error::last_os_error())
	} else {
	Ok(())
	}
	}
	}

	impl AsRawFd for VsockListener {
	fn as_raw_fd(&self) -> RawFd {
	self.socket
	}
	}

	impl FromRawFd for VsockListener {
	unsafe fn from_raw_fd(socket: RawFd) -> Self {
	Self { socket }
	}
	}

	impl IntoRawFd for VsockListener {
	fn into_raw_fd(self) -> RawFd {
	let fd = self.socket;
	mem::forget(self);
	fd
	}
	}

	impl Drop for VsockListener {
	fn drop(&mut self) {
	unsafe { close(self.socket) };
	}
	}

	/// A virtio stream between a local and a remote socket.
	#[derive(Debug, Clone)]
	pub struct VsockStream {
	socket: RawFd,
	}

	impl VsockStream {
	/// Open a connection to a remote host.
	pub fn connect(addr: &SockAddr) -> Result<Self> {
	let vsock_addr = if let SockAddr::Vsock(addr) = addr {
	addr.0
	} else {
	return Err(Error::new(
	ErrorKind::Other,
	"requires a virtio socket address",
	));
	};

	let sock = new_socket();
	if sock < 0 {
	return Err(Error::last_os_error());
	}
	if unsafe {
	connect(
	sock,
	&vsock_addr as const _ as const sockaddr,
	size_of::<sockaddr_vm>() as socklen_t,
	)
	} < 0
	{
	Err(Error::last_os_error())
	} else {
	Ok(unsafe { VsockStream::from_raw_fd(sock) })
	}
	}

	/// Open a connection to a remote host with specified cid and port.
	pub fn connect_with_cid_port(cid: u32, port: u32) -> Result<Self> {
	Self::connect(&SockAddr::Vsock(VsockAddr::new(cid, port)))
	}

	/// Virtio socket address of the remote peer associated with this connection.
	pub fn peer_addr(&self) -> Result<SockAddr> {
	let mut vsock_addr = sockaddr_vm {
	svm_family: AF_VSOCK as sa_family_t,
	svm_reserved1: 0,
	svm_port: 0,
	svm_cid: 0,
	svm_zero: [0u8; 4],
	};
	let mut vsock_addr_len = size_of::<sockaddr_vm>() as socklen_t;
	if unsafe {
	getpeername(
	self.socket,
	&mut vsock_addr as mut _ as mut sockaddr,
	&mut vsock_addr_len,
	)
	} < 0
	{
	Err(Error::last_os_error())
	} else {
	Ok(SockAddr::Vsock(VsockAddr(vsock_addr)))
	}
	}

	/// Virtio socket address of the local address associated with this connection.
	pub fn local_addr(&self) -> Result<SockAddr> {
	let mut vsock_addr = sockaddr_vm {
	svm_family: AF_VSOCK as sa_family_t,
	svm_reserved1: 0,
	svm_port: 0,
	svm_cid: 0,
	svm_zero: [0u8; 4],
	};
	let mut vsock_addr_len = size_of::<sockaddr_vm>() as socklen_t;
	if unsafe {
	getsockname(
	self.socket,
	&mut vsock_addr as mut _ as mut sockaddr,
	&mut vsock_addr_len,
	)
	} < 0
	{
	Err(Error::last_os_error())
	} else {
	Ok(SockAddr::Vsock(VsockAddr(vsock_addr)))
	}
	}

	/// Shutdown the read, write, or both halves of this connection.
	pub fn shutdown(&self, how: Shutdown) -> Result<()> {
	let how = match how {
	Shutdown::Write => SHUT_WR,
	Shutdown::Read => SHUT_RD,
	Shutdown::Both => SHUT_RDWR,
	};
	if unsafe { shutdown(self.socket, how) } < 0 {
	Err(Error::last_os_error())
	} else {
	Ok(())
	}
	}

	/// Create a new independently owned handle to the underlying socket.
	pub fn try_clone(&self) -> Result<Self> {
	Ok(self.clone())
	}

	/// Set the timeout on read operations.
	pub fn set_read_timeout(&self, dur: Option<Duration>) -> Result<()> {
	let timeout = Self::timeval_from_duration(dur)?;
	if unsafe {
	setsockopt(
	self.socket,
	SOL_SOCKET,
	SO_SNDTIMEO,
	&timeout as const _ as const c_void,
	size_of::<timeval>() as socklen_t,
	)
	} < 0
	{
	Err(Error::last_os_error())
	} else {
	Ok(())
	}
	}

	/// Set the timeout on write operations.
	pub fn set_write_timeout(&self, dur: Option<Duration>) -> Result<()> {
	let timeout = Self::timeval_from_duration(dur)?;
	if unsafe {
	setsockopt(
	self.socket,
	SOL_SOCKET,
	SO_RCVTIMEO,
	&timeout as const _ as const c_void,
	size_of::<timeval>() as socklen_t,
	)
	} < 0
	{
	Err(Error::last_os_error())
	} else {
	Ok(())
	}
	}

	/// Retrieve the latest error associated with the underlying socket.
	pub fn take_error(&self) -> Result<Option<Error>> {
	let mut error: i32 = 0;
	let mut error_len: socklen_t = 0;
	if unsafe {
	getsockopt(
	self.socket,
	SOL_SOCKET,
	SO_ERROR,
	&mut error as mut _ as mut c_void,
	&mut error_len,
	)
	} < 0
	{
	Err(Error::last_os_error())
	} else {
	Ok(if error == 0 {
	None
	} else {
	Some(Error::from_raw_os_error(error))
	})
	}
	}

	/// Move this stream in and out of nonblocking mode.
	pub fn set_nonblocking(&self, nonblocking: bool) -> Result<()> {
	let mut nonblocking: i32 = if nonblocking { 1 } else { 0 };
	if unsafe { ioctl(self.socket, FIONBIO, &mut nonblocking) } < 0 {
	Err(Error::last_os_error())
	} else {
	Ok(())
	}
	}

	fn timeval_from_duration(dur: Option<Duration>) -> Result<timeval> {
	match dur {
	Some(dur) => {
	if dur.as_secs() == 0 && dur.subsec_nanos() == 0 {
	return Err(Error::new(
	ErrorKind::InvalidInput,
	"cannot set a zero duration timeout",
	));
	}

	// https://github.com/rust-lang/libc/issues/1848
	#[cfg_attr(target_env = "musl", allow(deprecated))]
	let secs = if dur.as_secs() > time_t::max_value() as u64 {
	time_t::max_value()
	} else {
	dur.as_secs() as time_t
	};
	let mut timeout = timeval {
	tv_sec: secs,
	tv_usec: i64::from(dur.subsec_micros()) as suseconds_t,
	};
	if timeout.tv_sec == 0 && timeout.tv_usec == 0 {
	timeout.tv_usec = 1;
	}
	Ok(timeout)
	}
	None => Ok(timeval {
	tv_sec: 0,
	tv_usec: 0,
	}),
	}
	}
	}

	impl Read for VsockStream {
	fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
	<&Self>::read(&mut &*self, buf)
	}
	}

	impl Write for VsockStream {
	fn write(&mut self, buf: &[u8]) -> Result<usize> {
	<&Self>::write(&mut &*self, buf)
	}

	fn flush(&mut self) -> Result<()> {
	Ok(())
	}
	}

	impl Read for &VsockStream {
	fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
	let ret = unsafe { recv(self.socket, buf.as_mut_ptr() as *mut c_void, buf.len(), 0) };
	if ret < 0 {
	Err(Error::last_os_error())
	} else {
	Ok(ret as usize)
	}
	}
	}

	impl Write for &VsockStream {
	fn write(&mut self, buf: &[u8]) -> Result<usize> {
	let ret = unsafe {
	send(
	self.socket,
	buf.as_ptr() as *const c_void,
	buf.len(),
	MSG_NOSIGNAL,
	)
	};
	if ret < 0 {
	Err(Error::last_os_error())
	} else {
	Ok(ret as usize)
	}
	}

	fn flush(&mut self) -> Result<()> {
	Ok(())
	}
	}

	impl AsRawFd for VsockStream {
	fn as_raw_fd(&self) -> RawFd {
	self.socket
	}
	}

	impl FromRawFd for VsockStream {
	unsafe fn from_raw_fd(socket: RawFd) -> Self {
	Self { socket }
	}
	}

	impl IntoRawFd for VsockStream {
	fn into_raw_fd(self) -> RawFd {
	let fd = self.socket;
	mem::forget(self);
	fd
	}
	}

	impl Drop for VsockStream {
	fn drop(&mut self) {
	unsafe { close(self.socket) };
	}
	}

	const IOCTL_VM_SOCKETS_GET_LOCAL_CID: usize = 0x7b9;
	ioctl_read_bad!(
	vm_sockets_get_local_cid,
	IOCTL_VM_SOCKETS_GET_LOCAL_CID,
	u32
	);

	/// Gets the CID of the local machine.
	///
	/// Note that when calling [`VsockListener::bind`], you should generally use [`VMADDR_CID_ANY`]
	/// instead, and for making a loopback connection you should use [`VMADDR_CID_LOCAL`].
	pub fn get_local_cid() -> Result<u32> {
	let f = File::open("/dev/vsock")?;
	let mut cid = 0;
	// SAFETY: the kernel only modifies the given u32 integer.
	unsafe { vm_sockets_get_local_cid(f.as_raw_fd(), &mut cid) }?;
	Ok(cid)
	}