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//! Network related types. //! //! The network module support two types of protocols: //! //! * [Transmission Control Protocol] (TCP) module provides three main types: //! * A [TCP stream] between a local and a remote socket. //! * A [TCP listening socket], a socket used to listen for connections. //! * A [TCP server], listens for connections and starts a new actor for each. //! * [User Datagram Protocol] (UDP) only provides a single socket type: //! * [`UdpSocket`]. //! //! [Transmission Control Protocol]: crate::net::tcp //! [TCP stream]: crate::net::TcpStream //! [TCP listening socket]: crate::net::TcpListener //! [TCP server]: crate::net::TcpServer //! [User Datagram Protocol]: crate::net::udp //! //! # I/O with Heph's socket //! //! The different socket types provide two or three variants of most I/O //! functions. The `try_*` funtions, which makes the system calls once. For //! example [`TcpStream::try_send`] calls `send(2)` once, not handling any //! errors (including [`WouldBlock`] errors!). //! //! In addition they provide a [`Future`] function which handles would block //! errors. For `TcpStream::try_send` the future version is [`TcpStream::send`], //! i.e. without the `try_` prefix. //! //! Finally for a lot of function a convenience version is provided that handle //! various cases. For example with sending you might want to ensure all bytes //! are send, for this you can use [`TcpStream::send_all`]. But also see //! functions such as [`TcpStream::recv_n`]; which receives at least `n` bytes, //! or [`TcpStream::send_entire_file`]; which sends an entire file using the //! `sendfile(2)` system call. //! //! [`WouldBlock`]: io::ErrorKind::WouldBlock //! [`Future`]: std::future::Future //! //! # Notes //! //! All types in the `net` module around [bound] to an actor. See the //! [`actor::Bound`] trait for more information. //! //! [bound]: crate::actor::Bound //! [`actor::Bound`]: crate::actor::Bound use std::cmp::min; use std::mem::MaybeUninit; use std::net::SocketAddr; use std::ops::{Deref, DerefMut}; use std::{fmt, io, slice}; use socket2::SockAddr; /// A macro to try an I/O function. /// /// Note that this is used in the tcp and udp modules and has to be defined /// before them, otherwise this would have been place below. macro_rules! try_io { ($op: expr) => { loop { match $op { Ok(ok) => break Poll::Ready(Ok(ok)), Err(ref err) if err.kind() == io::ErrorKind::WouldBlock => break Poll::Pending, Err(ref err) if err.kind() == io::ErrorKind::Interrupted => continue, Err(err) => break Poll::Ready(Err(err)), } } }; } pub mod tcp; pub mod udp; #[doc(no_inline)] pub use tcp::{TcpListener, TcpServer, TcpStream}; #[doc(no_inline)] pub use udp::UdpSocket; /// Trait to make easier to work with uninitialised buffers. /// /// This is implemented for common types such as `Vec<u8>`, [see below]. /// /// [see below]: #foreign-impls pub trait Bytes { /// Returns itself as a slice of bytes that may or may not be initialised. /// /// # Notes /// /// The implementation must guarantee that two calls (without a call to /// [`update_length`] in between) returns the same slice of bytes. /// /// [`update_length`]: Bytes::update_length fn as_bytes(&mut self) -> &mut [MaybeUninit<u8>]; /// Returns the length of the buffer as returned by [`as_bytes`]. /// /// [`as_bytes`]: Bytes::as_bytes fn spare_capacity(&self) -> usize; /// Returns `true` if the buffer has spare capacity. fn has_spare_capacity(&self) -> bool { self.spare_capacity() == 0 } /// Update the length of the byte slice, marking `n` bytes as initialised. /// /// # Safety /// /// The caller must ensure that at least the first `n` bytes returned by /// [`as_bytes`] are initialised. /// /// [`as_bytes`]: Bytes::as_bytes /// /// # Notes /// /// If this method is not implemented correctly methods such as /// [`TcpStream::recv_n`] will not work correctly (as the buffer will /// overwrite itself on successive reads). unsafe fn update_length(&mut self, n: usize); /// Wrap the buffer in `LimitedBytes`, which limits the amount of bytes used /// to `limit`. /// /// [`LimitedBytes::into_inner`] can be used to retrieve the buffer again, /// or a mutable reference to the buffer can be used and the limited buffer /// be dropped after usage. fn limit(self, limit: usize) -> LimitedBytes<Self> where Self: Sized, { LimitedBytes { buf: self, limit } } } impl<B> Bytes for &mut B where B: Bytes + ?Sized, { fn as_bytes(&mut self) -> &mut [MaybeUninit<u8>] { (&mut **self).as_bytes() } fn spare_capacity(&self) -> usize { (&**self).spare_capacity() } fn has_spare_capacity(&self) -> bool { (&**self).has_spare_capacity() } unsafe fn update_length(&mut self, n: usize) { (&mut **self).update_length(n) } } /// The implementation for `Vec<u8>` only uses the uninitialised capacity of the /// vector. In other words the bytes currently in the vector remain untouched. /// /// # Examples /// /// The following example shows that the bytes already in the vector remain /// untouched. /// /// ``` /// use heph::net::Bytes; /// /// let mut buf = Vec::with_capacity(100); /// buf.extend(b"Hello world!"); /// /// write_bytes(b" Hello mars!", &mut buf); /// /// assert_eq!(&*buf, b"Hello world! Hello mars!"); /// /// fn write_bytes<B>(src: &[u8], mut buf: B) where B: Bytes { /// // Writes `src` to `buf`. /// # let dst = buf.as_bytes(); /// # let len = std::cmp::min(src.len(), dst.len()); /// # // Safety: both the src and dst pointers are good. And we've ensured /// # // that the length is correct, not overwriting data we don't own or /// # // reading data we don't own. /// # unsafe { /// # std::ptr::copy_nonoverlapping(src.as_ptr(), dst.as_mut_ptr().cast(), len); /// # buf.update_length(len); /// # } /// } /// ``` impl Bytes for Vec<u8> { fn as_bytes(&mut self) -> &mut [MaybeUninit<u8>] { self.spare_capacity_mut() } fn spare_capacity(&self) -> usize { self.capacity() - self.len() } fn has_spare_capacity(&self) -> bool { self.capacity() != self.len() } unsafe fn update_length(&mut self, n: usize) { let new = self.len() + n; debug_assert!(self.capacity() >= new); self.set_len(new); } } /// A version of [`IoSliceMut`] that allows the buffer to be uninitialised. /// /// [`IoSliceMut`]: std::io::IoSliceMut #[repr(transparent)] pub struct MaybeUninitSlice<'a>(socket2::MaybeUninitSlice<'a>); impl<'a> fmt::Debug for MaybeUninitSlice<'a> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { self.0.fmt(f) } } impl<'a> MaybeUninitSlice<'a> { /// Creates a new `MaybeUninitSlice` wrapping a byte slice. /// /// # Panics /// /// Panics on Windows if the slice is larger than 4GB. pub fn new(buf: &'a mut [MaybeUninit<u8>]) -> MaybeUninitSlice<'a> { MaybeUninitSlice(socket2::MaybeUninitSlice::new(buf)) } /// Creates a new `MaybeUninitSlice` from a [`Vec`]tor. /// /// Similar to the [`Bytes`] implementation for `Vec<u8>` this only uses the /// uninitialised capacity of the vector. /// /// # Panics /// /// Panics on Windows if the vector's uninitialised capacity is larger than /// 4GB. pub fn from_vec(buf: &'a mut Vec<u8>) -> MaybeUninitSlice<'a> { MaybeUninitSlice(socket2::MaybeUninitSlice::new(buf.as_bytes())) } fn limit(&mut self, limit: usize) { let len = self.len(); assert!(len >= limit); self.0 = unsafe { // SAFETY: this should be the line below, but I couldn't figure out // the lifetime. Since we're only making the slices smaller (as // checked by the assert above) this should be safe. //self.0 = socket2::MaybeUninitSlice::new(&mut self[..limit]); socket2::MaybeUninitSlice::new(slice::from_raw_parts_mut(self.0.as_mut_ptr(), limit)) }; } /// Returns `bufs` as [`socket2::MaybeUninitSlice`]. #[allow(clippy::wrong_self_convention)] fn as_socket2<'b>( bufs: &'b mut [MaybeUninitSlice<'a>], ) -> &'b mut [socket2::MaybeUninitSlice<'a>] { // Safety: this is safe because `MaybeUninitSlice` has the // `repr(transparent)` attribute. unsafe { &mut *(bufs as *mut _ as *mut _) } } } impl<'a> Deref for MaybeUninitSlice<'a> { type Target = [MaybeUninit<u8>]; fn deref(&self) -> &[MaybeUninit<u8>] { &*self.0 } } impl<'a> DerefMut for MaybeUninitSlice<'a> { fn deref_mut(&mut self) -> &mut [MaybeUninit<u8>] { &mut *self.0 } } /// Trait to make easier to work with uninitialised buffers using vectored I/O. /// /// This trait is implemented for arrays and tuples. When all of buffers are /// *homogeneous*, i.e. of the same type, the array implementation is the /// easiest to use along side with the [`Bytes`] trait. If however the buffers /// are *heterogeneous*, i.e. of different types, the tuple implementation can /// be used. See the examples below. /// /// # Examples /// /// Using the homogeneous array implementation. /// /// ``` /// # #![feature(maybe_uninit_write_slice)] /// use heph::net::BytesVectored; /// /// let mut buf1 = Vec::with_capacity(12); /// let mut buf2 = Vec::with_capacity(1); /// let mut buf3 = Vec::with_capacity(5); /// let mut buf4 = Vec::with_capacity(10); // Has extra capacity. /// /// let bufs = [&mut buf1, &mut buf2, &mut buf3, &mut buf4]; /// let text = b"Hello world. From mars!"; /// let bytes_written = write_vectored(bufs, text); /// assert_eq!(bytes_written, text.len()); /// /// assert_eq!(buf1, b"Hello world."); /// assert_eq!(buf2, b" "); /// assert_eq!(buf3, b"From "); /// assert_eq!(buf4, b"mars!"); /// /// /// Writes `text` to the `bufs`. /// fn write_vectored<B>(mut bufs: B, text: &[u8]) -> usize /// where B: BytesVectored, /// { /// // Implementation is not relevant to the example. /// # let mut written = 0; /// # let mut left = text; /// # for buf in bufs.as_bufs().as_mut().iter_mut() { /// # let n = std::cmp::min(buf.len(), left.len()); /// # let _ = std::mem::MaybeUninit::write_slice(&mut buf[..n], &left[..n]); /// # left = &left[n..]; /// # written += n; /// # if left.is_empty() { /// # break; /// # } /// # } /// # // NOTE: we could update the length of the buffers in the loop above, /// # // but this also acts as a smoke test for the implementation and this is /// # // what would happen with actual vectored I/O. /// # unsafe { bufs.update_lengths(written); } /// # written /// } /// ``` /// /// Using the heterogeneous tuple implementation. /// /// ``` /// # #![feature(maybe_uninit_uninit_array, maybe_uninit_slice, maybe_uninit_write_slice)] /// use std::mem::MaybeUninit; /// /// use heph::net::{Bytes, BytesVectored}; /// /// // Buffers of different types. /// let mut buf1 = Vec::with_capacity(12); /// let mut buf2 = StackBuf::new(); // Has extra capacity. /// /// // Using tuples we can use different kind of buffers. Here we use a `Vec` and /// // our own `StackBuf` type. /// let bufs = (&mut buf1, &mut buf2); /// let text = b"Hello world. From mars!"; /// let bytes_written = write_vectored(bufs, text); /// assert_eq!(bytes_written, text.len()); /// /// assert_eq!(buf1, b"Hello world."); /// assert_eq!(buf2.bytes(), b" From mars!"); /// /// /// Writes `text` to the `bufs`. /// fn write_vectored<B>(mut bufs: B, text: &[u8]) -> usize /// where B: BytesVectored, /// { /// // Implementation is not relevant to the example. /// # let mut written = 0; /// # let mut left = text; /// # for buf in bufs.as_bufs().as_mut().iter_mut() { /// # let n = std::cmp::min(buf.len(), left.len()); /// # let _ = MaybeUninit::write_slice(&mut buf[..n], &left[..n]); /// # left = &left[n..]; /// # written += n; /// # if left.is_empty() { /// # break; /// # } /// # } /// # // NOTE: we could update the length of the buffers in the loop above, /// # // but this also acts as a smoke test for the implementation and this is /// # // what would happen with actual vectored I/O. /// # unsafe { bufs.update_lengths(written); } /// # written /// } /// /// /// Custom stack buffer type that implements the `Bytes` trait. /// struct StackBuf { /// bytes: [MaybeUninit<u8>; 4096], /// initialised: usize, /// } /// /// impl StackBuf { /// fn new() -> StackBuf { /// StackBuf { /// bytes: MaybeUninit::uninit_array(), /// initialised: 0, /// } /// } /// /// fn bytes(&self) -> &[u8] { /// unsafe { MaybeUninit::slice_assume_init_ref(&self.bytes[..self.initialised]) } /// } /// } /// /// impl Bytes for StackBuf { /// fn as_bytes(&mut self) -> &mut [MaybeUninit<u8>] { /// &mut self.bytes[self.initialised..] /// } /// /// fn spare_capacity(&self) -> usize { /// self.bytes.len() - self.initialised /// } /// /// fn has_spare_capacity(&self) -> bool { /// self.bytes.len() != self.initialised /// } /// /// unsafe fn update_length(&mut self, n: usize) { /// self.initialised += n; /// } /// } /// ``` pub trait BytesVectored { /// Type used as slice of buffers, usually this is an array. type Bufs<'b>: AsMut<[MaybeUninitSlice<'b>]>; /// Returns itself as a slice of [`MaybeUninitSlice`]. fn as_bufs<'b>(&'b mut self) -> Self::Bufs<'b>; /// Returns the total length of the buffers as returned by [`as_bufs`]. /// /// [`as_bufs`]: BytesVectored::as_bufs fn spare_capacity(&self) -> usize; /// Returns `true` if (one of) the buffers has spare capacity. fn has_spare_capacity(&self) -> bool { self.spare_capacity() == 0 } /// Update the length of the buffers in the slice. /// /// # Safety /// /// The caller must ensure that at least the first `n` bytes returned by /// [`as_bufs`] are initialised, starting at the first buffer continuing /// into the next one, etc. /// /// [`as_bufs`]: BytesVectored::as_bufs /// /// # Notes /// /// If this method is not implemented correctly methods such as /// [`TcpStream::recv_n_vectored`] will not work correctly (as the buffer /// will overwrite itself on successive reads). unsafe fn update_lengths(&mut self, n: usize); /// Wrap the buffer in `LimitedBytes`, which limits the amount of bytes used /// to `limit`. /// /// [`LimitedBytes::into_inner`] can be used to retrieve the buffer again, /// or a mutable reference to the buffer can be used and the limited buffer /// be dropped after usage. fn limit(self, limit: usize) -> LimitedBytes<Self> where Self: Sized, { LimitedBytes { buf: self, limit } } } impl<B> BytesVectored for &mut B where B: BytesVectored + ?Sized, { type Bufs<'b> = B::Bufs<'b>; fn as_bufs<'b>(&'b mut self) -> Self::Bufs<'b> { (&mut **self).as_bufs() } fn spare_capacity(&self) -> usize { (&**self).spare_capacity() } fn has_spare_capacity(&self) -> bool { (&**self).has_spare_capacity() } unsafe fn update_lengths(&mut self, n: usize) { (&mut **self).update_lengths(n) } } impl<B, const N: usize> BytesVectored for [B; N] where B: Bytes, { type Bufs<'b> = [MaybeUninitSlice<'b>; N]; fn as_bufs<'b>(&'b mut self) -> Self::Bufs<'b> { let mut bufs = MaybeUninit::uninit_array::<N>(); for (i, buf) in self.iter_mut().enumerate() { let _ = bufs[i].write(MaybeUninitSlice::new(buf.as_bytes())); } // Safety: initialised the buffers above. unsafe { MaybeUninit::array_assume_init(bufs) } } fn spare_capacity(&self) -> usize { self.iter().map(|b| b.spare_capacity()).sum() } fn has_spare_capacity(&self) -> bool { self.iter().any(|b| b.has_spare_capacity()) } unsafe fn update_lengths(&mut self, n: usize) { let mut left = n; for buf in self.iter_mut() { let n = min(left, buf.spare_capacity()); buf.update_length(n); left -= n; if left == 0 { return; } } } } macro_rules! impl_vectored_bytes_tuple { ( $N: tt : $( $t: ident $idx: tt ),+ ) => { impl<$( $t ),+> BytesVectored for ( $( $t ),+ ) where $( $t: Bytes ),+ { type Bufs<'b> = [MaybeUninitSlice<'b>; $N]; fn as_bufs<'b>(&'b mut self) -> Self::Bufs<'b> { let mut bufs = MaybeUninit::uninit_array::<$N>(); $( let _ = bufs[$idx].write(MaybeUninitSlice::new(self.$idx.as_bytes())); )+ // Safety: initialised the buffers above. unsafe { MaybeUninit::array_assume_init(bufs) } } fn spare_capacity(&self) -> usize { $( self.$idx.spare_capacity() + )+ 0 } fn has_spare_capacity(&self) -> bool { $( self.$idx.has_spare_capacity() || )+ false } unsafe fn update_lengths(&mut self, n: usize) { let mut left = n; $( let n = min(left, self.$idx.spare_capacity()); self.$idx.update_length(n); left -= n; if left == 0 { return; } )+ } } }; } impl_vectored_bytes_tuple! { 12: B0 0, B1 1, B2 2, B3 3, B4 4, B5 5, B6 6, B7 7, B8 8, B9 9, B10 10, B11 11 } impl_vectored_bytes_tuple! { 11: B0 0, B1 1, B2 2, B3 3, B4 4, B5 5, B6 6, B7 7, B8 8, B9 9, B10 10 } impl_vectored_bytes_tuple! { 10: B0 0, B1 1, B2 2, B3 3, B4 4, B5 5, B6 6, B7 7, B8 8, B9 9 } impl_vectored_bytes_tuple! { 9: B0 0, B1 1, B2 2, B3 3, B4 4, B5 5, B6 6, B7 7, B8 8 } impl_vectored_bytes_tuple! { 8: B0 0, B1 1, B2 2, B3 3, B4 4, B5 5, B6 6, B7 7 } impl_vectored_bytes_tuple! { 7: B0 0, B1 1, B2 2, B3 3, B4 4, B5 5, B6 6 } impl_vectored_bytes_tuple! { 6: B0 0, B1 1, B2 2, B3 3, B4 4, B5 5 } impl_vectored_bytes_tuple! { 5: B0 0, B1 1, B2 2, B3 3, B4 4 } impl_vectored_bytes_tuple! { 4: B0 0, B1 1, B2 2, B3 3 } impl_vectored_bytes_tuple! { 3: B0 0, B1 1, B2 2 } impl_vectored_bytes_tuple! { 2: B0 0, B1 1 } /// Wrapper to limit the number of bytes `B` can use. /// /// See [`Bytes::limit`] and [`BytesVectored::limit`]. #[derive(Debug)] pub struct LimitedBytes<B> { buf: B, limit: usize, } impl<B> LimitedBytes<B> { /// Returns the underlying buffer. pub fn into_inner(self) -> B { self.buf } } impl<B> Bytes for LimitedBytes<B> where B: Bytes, { fn as_bytes(&mut self) -> &mut [MaybeUninit<u8>] { let bytes = self.buf.as_bytes(); if bytes.len() > self.limit { &mut bytes[..self.limit] } else { bytes } } fn spare_capacity(&self) -> usize { min(self.buf.spare_capacity(), self.limit) } fn has_spare_capacity(&self) -> bool { self.spare_capacity() > 0 } unsafe fn update_length(&mut self, n: usize) { self.buf.update_length(n); self.limit -= n; } } impl<B> BytesVectored for LimitedBytes<B> where B: BytesVectored, { type Bufs<'b> = B::Bufs<'b>; fn as_bufs<'b>(&'b mut self) -> Self::Bufs<'b> { let mut bufs = self.buf.as_bufs(); let mut left = self.limit; let mut iter = bufs.as_mut().iter_mut(); while let Some(buf) = iter.next() { let len = buf.len(); if left > len { left -= len; } else { buf.limit(left); for buf in iter { *buf = MaybeUninitSlice::new(&mut []); } break; } } bufs } fn spare_capacity(&self) -> usize { if self.limit == 0 { 0 } else { min(self.buf.spare_capacity(), self.limit) } } fn has_spare_capacity(&self) -> bool { self.limit != 0 && self.buf.has_spare_capacity() } unsafe fn update_lengths(&mut self, n: usize) { self.buf.update_lengths(n); self.limit -= n; } } /// Convert a `socket2:::SockAddr` into a `std::net::SocketAddr`. #[allow(clippy::needless_pass_by_value)] fn convert_address(address: SockAddr) -> io::Result<SocketAddr> { match address.as_socket() { Some(address) => Ok(address), None => Err(io::Error::new( io::ErrorKind::InvalidInput, "invalid address family (not IPv4 or IPv6)", )), } }