diff options
Diffstat (limited to 'vendor/rustix/src/net/send_recv')
| -rw-r--r-- | vendor/rustix/src/net/send_recv/mod.rs | 380 | ||||
| -rw-r--r-- | vendor/rustix/src/net/send_recv/msg.rs | 966 |
2 files changed, 1346 insertions, 0 deletions
diff --git a/vendor/rustix/src/net/send_recv/mod.rs b/vendor/rustix/src/net/send_recv/mod.rs new file mode 100644 index 0000000..cad2d5c --- /dev/null +++ b/vendor/rustix/src/net/send_recv/mod.rs @@ -0,0 +1,380 @@ +//! `recv`, `send`, and variants. + +#![allow(unsafe_code)] + +use crate::buffer::split_init; +#[cfg(unix)] +use crate::net::SocketAddrUnix; +use crate::net::{SocketAddr, SocketAddrAny, SocketAddrV4, SocketAddrV6}; +use crate::{backend, io}; +use backend::fd::{AsFd, BorrowedFd}; +use core::mem::MaybeUninit; + +pub use backend::net::send_recv::{RecvFlags, SendFlags}; + +#[cfg(not(any( + windows, + target_os = "espidf", + target_os = "redox", + target_os = "vita", + target_os = "wasi" +)))] +mod msg; + +#[cfg(not(any( + windows, + target_os = "espidf", + target_os = "redox", + target_os = "vita", + target_os = "wasi" +)))] +pub use msg::*; + +/// `recv(fd, buf, flags)`—Reads data from a socket. +/// +/// # References +/// - [Beej's Guide to Network Programming] +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [Winsock] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// - [glibc] +/// +/// [Beej's Guide to Network Programming]: https://beej.us/guide/bgnet/html/split/system-calls-or-bust.html#sendrecv +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/recv.html +/// [Linux]: https://man7.org/linux/man-pages/man2/recv.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/recv.2.html +/// [Winsock]: https://docs.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-recv +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=recv&sektion=2 +/// [NetBSD]: https://man.netbsd.org/recv.2 +/// [OpenBSD]: https://man.openbsd.org/recv.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=recv§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/recv +/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Receiving-Data.html +#[inline] +pub fn recv<Fd: AsFd>(fd: Fd, buf: &mut [u8], flags: RecvFlags) -> io::Result<usize> { + unsafe { backend::net::syscalls::recv(fd.as_fd(), buf.as_mut_ptr(), buf.len(), flags) } +} + +/// `recv(fd, buf, flags)`—Reads data from a socket. +/// +/// This is equivalent to [`recv`], except that it can read into uninitialized +/// memory. It returns the slice that was initialized by this function and the +/// slice that remains uninitialized. +#[inline] +pub fn recv_uninit<Fd: AsFd>( + fd: Fd, + buf: &mut [MaybeUninit<u8>], + flags: RecvFlags, +) -> io::Result<(&mut [u8], &mut [MaybeUninit<u8>])> { + let length = unsafe { + backend::net::syscalls::recv(fd.as_fd(), buf.as_mut_ptr() as *mut u8, buf.len(), flags) + }; + + Ok(unsafe { split_init(buf, length?) }) +} + +/// `send(fd, buf, flags)`—Writes data to a socket. +/// +/// # References +/// - [Beej's Guide to Network Programming] +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [Winsock] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// - [glibc] +/// +/// [Beej's Guide to Network Programming]: https://beej.us/guide/bgnet/html/split/system-calls-or-bust.html#sendrecv +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/send.html +/// [Linux]: https://man7.org/linux/man-pages/man2/send.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/send.2.html +/// [Winsock]: https://docs.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-send +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=send&sektion=2 +/// [NetBSD]: https://man.netbsd.org/send.2 +/// [OpenBSD]: https://man.openbsd.org/send.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=send§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/send +/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Sending-Data.html +#[inline] +pub fn send<Fd: AsFd>(fd: Fd, buf: &[u8], flags: SendFlags) -> io::Result<usize> { + backend::net::syscalls::send(fd.as_fd(), buf, flags) +} + +/// `recvfrom(fd, buf, flags, addr, len)`—Reads data from a socket and +/// returns the sender address. +/// +/// # References +/// - [Beej's Guide to Network Programming] +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [Winsock] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// - [glibc] +/// +/// [Beej's Guide to Network Programming]: https://beej.us/guide/bgnet/html/split/system-calls-or-bust.html#sendtorecv +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/recvfrom.html +/// [Linux]: https://man7.org/linux/man-pages/man2/recvfrom.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/recvfrom.2.html +/// [Winsock]: https://docs.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-recvfrom +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=recvfrom&sektion=2 +/// [NetBSD]: https://man.netbsd.org/recvfrom.2 +/// [OpenBSD]: https://man.openbsd.org/recvfrom.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=recvfrom§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/recvfrom +/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Receiving-Datagrams.html +#[inline] +pub fn recvfrom<Fd: AsFd>( + fd: Fd, + buf: &mut [u8], + flags: RecvFlags, +) -> io::Result<(usize, Option<SocketAddrAny>)> { + unsafe { backend::net::syscalls::recvfrom(fd.as_fd(), buf.as_mut_ptr(), buf.len(), flags) } +} + +/// `recvfrom(fd, buf, flags, addr, len)`—Reads data from a socket and +/// returns the sender address. +/// +/// This is equivalent to [`recvfrom`], except that it can read into +/// uninitialized memory. It returns the slice that was initialized by this +/// function and the slice that remains uninitialized. +#[allow(clippy::type_complexity)] +#[inline] +pub fn recvfrom_uninit<Fd: AsFd>( + fd: Fd, + buf: &mut [MaybeUninit<u8>], + flags: RecvFlags, +) -> io::Result<(&mut [u8], &mut [MaybeUninit<u8>], Option<SocketAddrAny>)> { + let (length, addr) = unsafe { + backend::net::syscalls::recvfrom(fd.as_fd(), buf.as_mut_ptr() as *mut u8, buf.len(), flags)? + }; + let (init, uninit) = unsafe { split_init(buf, length) }; + Ok((init, uninit, addr)) +} + +/// `sendto(fd, buf, flags, addr)`—Writes data to a socket to a specific IP +/// address. +/// +/// # References +/// - [Beej's Guide to Network Programming] +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [Winsock] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// - [glibc] +/// +/// [Beej's Guide to Network Programming]: https://beej.us/guide/bgnet/html/split/system-calls-or-bust.html#sendtorecv +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendto.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendto.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendto.2.html +/// [Winsock]: https://docs.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-sendto +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendto&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendto.2 +/// [OpenBSD]: https://man.openbsd.org/sendto.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendto§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendto +/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Sending-Datagrams.html +pub fn sendto<Fd: AsFd>( + fd: Fd, + buf: &[u8], + flags: SendFlags, + addr: &SocketAddr, +) -> io::Result<usize> { + _sendto(fd.as_fd(), buf, flags, addr) +} + +fn _sendto( + fd: BorrowedFd<'_>, + buf: &[u8], + flags: SendFlags, + addr: &SocketAddr, +) -> io::Result<usize> { + match addr { + SocketAddr::V4(v4) => backend::net::syscalls::sendto_v4(fd, buf, flags, v4), + SocketAddr::V6(v6) => backend::net::syscalls::sendto_v6(fd, buf, flags, v6), + } +} + +/// `sendto(fd, buf, flags, addr)`—Writes data to a socket to a specific +/// address. +/// +/// # References +/// - [Beej's Guide to Network Programming] +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [Winsock] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// - [glibc] +/// +/// [Beej's Guide to Network Programming]: https://beej.us/guide/bgnet/html/split/system-calls-or-bust.html#sendtorecv +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendto.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendto.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendto.2.html +/// [Winsock]: https://docs.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-sendto +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendto&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendto.2 +/// [OpenBSD]: https://man.openbsd.org/sendto.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendto§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendto +/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Sending-Datagrams.html +pub fn sendto_any<Fd: AsFd>( + fd: Fd, + buf: &[u8], + flags: SendFlags, + addr: &SocketAddrAny, +) -> io::Result<usize> { + _sendto_any(fd.as_fd(), buf, flags, addr) +} + +fn _sendto_any( + fd: BorrowedFd<'_>, + buf: &[u8], + flags: SendFlags, + addr: &SocketAddrAny, +) -> io::Result<usize> { + match addr { + SocketAddrAny::V4(v4) => backend::net::syscalls::sendto_v4(fd, buf, flags, v4), + SocketAddrAny::V6(v6) => backend::net::syscalls::sendto_v6(fd, buf, flags, v6), + #[cfg(unix)] + SocketAddrAny::Unix(unix) => backend::net::syscalls::sendto_unix(fd, buf, flags, unix), + } +} + +/// `sendto(fd, buf, flags, addr, sizeof(struct sockaddr_in))`—Writes data to +/// a socket to a specific IPv4 address. +/// +/// # References +/// - [Beej's Guide to Network Programming] +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [Winsock] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// - [glibc] +/// +/// [Beej's Guide to Network Programming]: https://beej.us/guide/bgnet/html/split/system-calls-or-bust.html#sendtorecv +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendto.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendto.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendto.2.html +/// [Winsock]: https://docs.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-sendto +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendto&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendto.2 +/// [OpenBSD]: https://man.openbsd.org/sendto.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendto§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendto +/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Sending-Datagrams.html +#[inline] +#[doc(alias = "sendto")] +pub fn sendto_v4<Fd: AsFd>( + fd: Fd, + buf: &[u8], + flags: SendFlags, + addr: &SocketAddrV4, +) -> io::Result<usize> { + backend::net::syscalls::sendto_v4(fd.as_fd(), buf, flags, addr) +} + +/// `sendto(fd, buf, flags, addr, sizeof(struct sockaddr_in6))`—Writes data +/// to a socket to a specific IPv6 address. +/// +/// # References +/// - [Beej's Guide to Network Programming] +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [Winsock] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// - [glibc] +/// +/// [Beej's Guide to Network Programming]: https://beej.us/guide/bgnet/html/split/system-calls-or-bust.html#sendtorecv +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendto.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendto.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendto.2.html +/// [Winsock]: https://docs.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-sendto +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendto&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendto.2 +/// [OpenBSD]: https://man.openbsd.org/sendto.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendto§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendto +/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Sending-Datagrams.html +#[inline] +#[doc(alias = "sendto")] +pub fn sendto_v6<Fd: AsFd>( + fd: Fd, + buf: &[u8], + flags: SendFlags, + addr: &SocketAddrV6, +) -> io::Result<usize> { + backend::net::syscalls::sendto_v6(fd.as_fd(), buf, flags, addr) +} + +/// `sendto(fd, buf, flags, addr, sizeof(struct sockaddr_un))`—Writes data to +/// a socket to a specific Unix-domain socket address. +/// +/// # References +/// - [Beej's Guide to Network Programming] +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [Winsock] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// - [glibc] +/// +/// [Beej's Guide to Network Programming]: https://beej.us/guide/bgnet/html/split/system-calls-or-bust.html#sendtorecv +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendto.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendto.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendto.2.html +/// [Winsock]: https://docs.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-sendto +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendto&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendto.2 +/// [OpenBSD]: https://man.openbsd.org/sendto.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendto§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendto +/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Sending-Datagrams.html +#[cfg(unix)] +#[inline] +#[doc(alias = "sendto")] +pub fn sendto_unix<Fd: AsFd>( + fd: Fd, + buf: &[u8], + flags: SendFlags, + addr: &SocketAddrUnix, +) -> io::Result<usize> { + backend::net::syscalls::sendto_unix(fd.as_fd(), buf, flags, addr) +} diff --git a/vendor/rustix/src/net/send_recv/msg.rs b/vendor/rustix/src/net/send_recv/msg.rs new file mode 100644 index 0000000..78fb865 --- /dev/null +++ b/vendor/rustix/src/net/send_recv/msg.rs @@ -0,0 +1,966 @@ +//! [`recvmsg`], [`sendmsg`], and related functions. + +#![allow(unsafe_code)] + +use crate::backend::{self, c}; +use crate::fd::{AsFd, BorrowedFd, OwnedFd}; +use crate::io::{self, IoSlice, IoSliceMut}; +#[cfg(linux_kernel)] +use crate::net::UCred; + +use core::iter::FusedIterator; +use core::marker::PhantomData; +use core::mem::{align_of, size_of, size_of_val, take}; +#[cfg(linux_kernel)] +use core::ptr::addr_of; +use core::{ptr, slice}; + +use super::{RecvFlags, SendFlags, SocketAddrAny, SocketAddrV4, SocketAddrV6}; + +/// Macro for defining the amount of space to allocate in a buffer for use with +/// [`RecvAncillaryBuffer::new`] and [`SendAncillaryBuffer::new`]. +/// +/// # Examples +/// +/// Allocate a buffer for a single file descriptor: +/// ``` +/// # use rustix::cmsg_space; +/// let mut space = [0; rustix::cmsg_space!(ScmRights(1))]; +/// ``` +/// +/// Allocate a buffer for credentials: +/// ``` +/// # #[cfg(linux_kernel)] +/// # { +/// # use rustix::cmsg_space; +/// let mut space = [0; rustix::cmsg_space!(ScmCredentials(1))]; +/// # } +/// ``` +/// +/// Allocate a buffer for two file descriptors and credentials: +/// ``` +/// # #[cfg(linux_kernel)] +/// # { +/// # use rustix::cmsg_space; +/// let mut space = [0; rustix::cmsg_space!(ScmRights(2), ScmCredentials(1))]; +/// # } +/// ``` +#[macro_export] +macro_rules! cmsg_space { + // Base Rules + (ScmRights($len:expr)) => { + $crate::net::__cmsg_space( + $len * ::core::mem::size_of::<$crate::fd::BorrowedFd<'static>>(), + ) + }; + (ScmCredentials($len:expr)) => { + $crate::net::__cmsg_space( + $len * ::core::mem::size_of::<$crate::net::UCred>(), + ) + }; + + // Combo Rules + ($firstid:ident($firstex:expr), $($restid:ident($restex:expr)),*) => {{ + // We only have to add `cmsghdr` alignment once; all other times we can + // use `cmsg_aligned_space`. + let sum = $crate::cmsg_space!($firstid($firstex)); + $( + let sum = sum + $crate::cmsg_aligned_space!($restid($restex)); + )* + sum + }}; +} + +/// Like `cmsg_space`, but doesn't add padding for `cmsghdr` alignment. +#[doc(hidden)] +#[macro_export] +macro_rules! cmsg_aligned_space { + // Base Rules + (ScmRights($len:expr)) => { + $crate::net::__cmsg_aligned_space( + $len * ::core::mem::size_of::<$crate::fd::BorrowedFd<'static>>(), + ) + }; + (ScmCredentials($len:expr)) => { + $crate::net::__cmsg_aligned_space( + $len * ::core::mem::size_of::<$crate::net::UCred>(), + ) + }; + + // Combo Rules + ($firstid:ident($firstex:expr), $($restid:ident($restex:expr)),*) => {{ + let sum = cmsg_aligned_space!($firstid($firstex)); + $( + let sum = sum + cmsg_aligned_space!($restid($restex)); + )* + sum + }}; +} + +#[doc(hidden)] +pub const fn __cmsg_space(len: usize) -> usize { + // Add `align_of::<c::cmsghdr>()` so that we can align the user-provided + // `&[u8]` to the required alignment boundary. + let len = len + align_of::<c::cmsghdr>(); + + __cmsg_aligned_space(len) +} + +#[doc(hidden)] +pub const fn __cmsg_aligned_space(len: usize) -> usize { + // Convert `len` to `u32` for `CMSG_SPACE`. This would be `try_into()` if + // we could call that in a `const fn`. + let converted_len = len as u32; + if converted_len as usize != len { + unreachable!(); // `CMSG_SPACE` size overflow + } + + unsafe { c::CMSG_SPACE(converted_len) as usize } +} + +/// Ancillary message for [`sendmsg`], [`sendmsg_v4`], [`sendmsg_v6`], +/// [`sendmsg_unix`], and [`sendmsg_any`]. +#[non_exhaustive] +pub enum SendAncillaryMessage<'slice, 'fd> { + /// Send file descriptors. + #[doc(alias = "SCM_RIGHTS")] + ScmRights(&'slice [BorrowedFd<'fd>]), + /// Send process credentials. + #[cfg(linux_kernel)] + #[doc(alias = "SCM_CREDENTIAL")] + ScmCredentials(UCred), +} + +impl SendAncillaryMessage<'_, '_> { + /// Get the maximum size of an ancillary message. + /// + /// This can be helpful in determining the size of the buffer you allocate. + pub const fn size(&self) -> usize { + match self { + Self::ScmRights(slice) => cmsg_space!(ScmRights(slice.len())), + #[cfg(linux_kernel)] + Self::ScmCredentials(_) => cmsg_space!(ScmCredentials(1)), + } + } +} + +/// Ancillary message for [`recvmsg`]. +#[non_exhaustive] +pub enum RecvAncillaryMessage<'a> { + /// Received file descriptors. + #[doc(alias = "SCM_RIGHTS")] + ScmRights(AncillaryIter<'a, OwnedFd>), + /// Received process credentials. + #[cfg(linux_kernel)] + #[doc(alias = "SCM_CREDENTIALS")] + ScmCredentials(UCred), +} + +/// Buffer for sending ancillary messages with [`sendmsg`], [`sendmsg_v4`], +/// [`sendmsg_v6`], [`sendmsg_unix`], and [`sendmsg_any`]. +/// +/// Use the [`push`] function to add messages to send. +/// +/// [`push`]: SendAncillaryBuffer::push +pub struct SendAncillaryBuffer<'buf, 'slice, 'fd> { + /// Raw byte buffer for messages. + buffer: &'buf mut [u8], + + /// The amount of the buffer that is used. + length: usize, + + /// Phantom data for lifetime of `&'slice [BorrowedFd<'fd>]`. + _phantom: PhantomData<&'slice [BorrowedFd<'fd>]>, +} + +impl<'buf> From<&'buf mut [u8]> for SendAncillaryBuffer<'buf, '_, '_> { + fn from(buffer: &'buf mut [u8]) -> Self { + Self::new(buffer) + } +} + +impl Default for SendAncillaryBuffer<'_, '_, '_> { + fn default() -> Self { + Self { + buffer: &mut [], + length: 0, + _phantom: PhantomData, + } + } +} + +impl<'buf, 'slice, 'fd> SendAncillaryBuffer<'buf, 'slice, 'fd> { + /// Create a new, empty `SendAncillaryBuffer` from a raw byte buffer. + /// + /// The buffer size may be computed with [`cmsg_space`], or it may be + /// zero for an empty buffer, however in that case, consider `default()` + /// instead, or even using [`send`] instead of `sendmsg`. + /// + /// # Examples + /// + /// Allocate a buffer for a single file descriptor: + /// ``` + /// # use rustix::cmsg_space; + /// # use rustix::net::SendAncillaryBuffer; + /// let mut space = [0; rustix::cmsg_space!(ScmRights(1))]; + /// let mut cmsg_buffer = SendAncillaryBuffer::new(&mut space); + /// ``` + /// + /// Allocate a buffer for credentials: + /// ``` + /// # #[cfg(linux_kernel)] + /// # { + /// # use rustix::cmsg_space; + /// # use rustix::net::SendAncillaryBuffer; + /// let mut space = [0; rustix::cmsg_space!(ScmCredentials(1))]; + /// let mut cmsg_buffer = SendAncillaryBuffer::new(&mut space); + /// # } + /// ``` + /// + /// Allocate a buffer for two file descriptors and credentials: + /// ``` + /// # #[cfg(linux_kernel)] + /// # { + /// # use rustix::cmsg_space; + /// # use rustix::net::SendAncillaryBuffer; + /// let mut space = [0; rustix::cmsg_space!(ScmRights(2), ScmCredentials(1))]; + /// let mut cmsg_buffer = SendAncillaryBuffer::new(&mut space); + /// # } + /// ``` + /// + /// [`send`]: crate::net::send + #[inline] + pub fn new(buffer: &'buf mut [u8]) -> Self { + Self { + buffer: align_for_cmsghdr(buffer), + length: 0, + _phantom: PhantomData, + } + } + + /// Returns a pointer to the message data. + pub(crate) fn as_control_ptr(&mut self) -> *mut u8 { + // When the length is zero, we may be using a `&[]` address, which may + // be an invalid but non-null pointer, and on some platforms, that + // causes `sendmsg` to fail with `EFAULT` or `EINVAL` + #[cfg(not(linux_kernel))] + if self.length == 0 { + return core::ptr::null_mut(); + } + + self.buffer.as_mut_ptr() + } + + /// Returns the length of the message data. + pub(crate) fn control_len(&self) -> usize { + self.length + } + + /// Delete all messages from the buffer. + pub fn clear(&mut self) { + self.length = 0; + } + + /// Add an ancillary message to the buffer. + /// + /// Returns `true` if the message was added successfully. + pub fn push(&mut self, msg: SendAncillaryMessage<'slice, 'fd>) -> bool { + match msg { + SendAncillaryMessage::ScmRights(fds) => { + let fds_bytes = + unsafe { slice::from_raw_parts(fds.as_ptr().cast::<u8>(), size_of_val(fds)) }; + self.push_ancillary(fds_bytes, c::SOL_SOCKET as _, c::SCM_RIGHTS as _) + } + #[cfg(linux_kernel)] + SendAncillaryMessage::ScmCredentials(ucred) => { + let ucred_bytes = unsafe { + slice::from_raw_parts(addr_of!(ucred).cast::<u8>(), size_of_val(&ucred)) + }; + self.push_ancillary(ucred_bytes, c::SOL_SOCKET as _, c::SCM_CREDENTIALS as _) + } + } + } + + /// Pushes an ancillary message to the buffer. + fn push_ancillary(&mut self, source: &[u8], cmsg_level: c::c_int, cmsg_type: c::c_int) -> bool { + macro_rules! leap { + ($e:expr) => {{ + match ($e) { + Some(x) => x, + None => return false, + } + }}; + } + + // Calculate the length of the message. + let source_len = leap!(u32::try_from(source.len()).ok()); + + // Calculate the new length of the buffer. + let additional_space = unsafe { c::CMSG_SPACE(source_len) }; + let new_length = leap!(self.length.checked_add(additional_space as usize)); + let buffer = leap!(self.buffer.get_mut(..new_length)); + + // Fill the new part of the buffer with zeroes. + buffer[self.length..new_length].fill(0); + self.length = new_length; + + // Get the last header in the buffer. + let last_header = leap!(messages::Messages::new(buffer).last()); + + // Set the header fields. + last_header.cmsg_len = unsafe { c::CMSG_LEN(source_len) } as _; + last_header.cmsg_level = cmsg_level; + last_header.cmsg_type = cmsg_type; + + // Get the pointer to the payload and copy the data. + unsafe { + let payload = c::CMSG_DATA(last_header); + ptr::copy_nonoverlapping(source.as_ptr(), payload, source_len as _); + } + + true + } +} + +impl<'slice, 'fd> Extend<SendAncillaryMessage<'slice, 'fd>> + for SendAncillaryBuffer<'_, 'slice, 'fd> +{ + fn extend<T: IntoIterator<Item = SendAncillaryMessage<'slice, 'fd>>>(&mut self, iter: T) { + // TODO: This could be optimized to add every message in one go. + iter.into_iter().all(|msg| self.push(msg)); + } +} + +/// Buffer for receiving ancillary messages with [`recvmsg`]. +/// +/// Use the [`drain`] function to iterate over the received messages. +/// +/// [`drain`]: RecvAncillaryBuffer::drain +#[derive(Default)] +pub struct RecvAncillaryBuffer<'buf> { + /// Raw byte buffer for messages. + buffer: &'buf mut [u8], + + /// The portion of the buffer we've read from already. + read: usize, + + /// The amount of the buffer that is used. + length: usize, +} + +impl<'buf> From<&'buf mut [u8]> for RecvAncillaryBuffer<'buf> { + fn from(buffer: &'buf mut [u8]) -> Self { + Self::new(buffer) + } +} + +impl<'buf> RecvAncillaryBuffer<'buf> { + /// Create a new, empty `RecvAncillaryBuffer` from a raw byte buffer. + /// + /// The buffer size may be computed with [`cmsg_space`], or it may be + /// zero for an empty buffer, however in that case, consider `default()` + /// instead, or even using [`recv`] instead of `recvmsg`. + /// + /// # Examples + /// + /// Allocate a buffer for a single file descriptor: + /// ``` + /// # use rustix::cmsg_space; + /// # use rustix::net::RecvAncillaryBuffer; + /// let mut space = [0; rustix::cmsg_space!(ScmRights(1))]; + /// let mut cmsg_buffer = RecvAncillaryBuffer::new(&mut space); + /// ``` + /// + /// Allocate a buffer for credentials: + /// ``` + /// # #[cfg(linux_kernel)] + /// # { + /// # use rustix::cmsg_space; + /// # use rustix::net::RecvAncillaryBuffer; + /// let mut space = [0; rustix::cmsg_space!(ScmCredentials(1))]; + /// let mut cmsg_buffer = RecvAncillaryBuffer::new(&mut space); + /// # } + /// ``` + /// + /// Allocate a buffer for two file descriptors and credentials: + /// ``` + /// # #[cfg(linux_kernel)] + /// # { + /// # use rustix::cmsg_space; + /// # use rustix::net::RecvAncillaryBuffer; + /// let mut space = [0; rustix::cmsg_space!(ScmRights(2), ScmCredentials(1))]; + /// let mut cmsg_buffer = RecvAncillaryBuffer::new(&mut space); + /// # } + /// ``` + /// + /// [`recv`]: crate::net::recv + #[inline] + pub fn new(buffer: &'buf mut [u8]) -> Self { + Self { + buffer: align_for_cmsghdr(buffer), + read: 0, + length: 0, + } + } + + /// Returns a pointer to the message data. + pub(crate) fn as_control_ptr(&mut self) -> *mut u8 { + // When the length is zero, we may be using a `&[]` address, which may + // be an invalid but non-null pointer, and on some platforms, that + // causes `sendmsg` to fail with `EFAULT` or `EINVAL` + #[cfg(not(linux_kernel))] + if self.buffer.is_empty() { + return core::ptr::null_mut(); + } + + self.buffer.as_mut_ptr() + } + + /// Returns the length of the message data. + pub(crate) fn control_len(&self) -> usize { + self.buffer.len() + } + + /// Set the length of the message data. + /// + /// # Safety + /// + /// The buffer must be filled with valid message data. + pub(crate) unsafe fn set_control_len(&mut self, len: usize) { + self.length = len; + self.read = 0; + } + + /// Delete all messages from the buffer. + pub(crate) fn clear(&mut self) { + self.drain().for_each(drop); + } + + /// Drain all messages from the buffer. + pub fn drain(&mut self) -> AncillaryDrain<'_> { + AncillaryDrain { + messages: messages::Messages::new(&mut self.buffer[self.read..][..self.length]), + read: &mut self.read, + length: &mut self.length, + } + } +} + +impl Drop for RecvAncillaryBuffer<'_> { + fn drop(&mut self) { + self.clear(); + } +} + +/// Return a slice of `buffer` starting at the first `cmsghdr` alignment +/// boundary. +#[inline] +fn align_for_cmsghdr(buffer: &mut [u8]) -> &mut [u8] { + // If the buffer is empty, we won't be writing anything into it, so it + // doesn't need to be aligned. + if buffer.is_empty() { + return buffer; + } + + let align = align_of::<c::cmsghdr>(); + let addr = buffer.as_ptr() as usize; + let adjusted = (addr + (align - 1)) & align.wrapping_neg(); + &mut buffer[adjusted - addr..] +} + +/// An iterator that drains messages from a [`RecvAncillaryBuffer`]. +pub struct AncillaryDrain<'buf> { + /// Inner iterator over messages. + messages: messages::Messages<'buf>, + + /// Increment the number of messages we've read. + read: &'buf mut usize, + + /// Decrement the total length. + length: &'buf mut usize, +} + +impl<'buf> AncillaryDrain<'buf> { + /// A closure that converts a message into a [`RecvAncillaryMessage`]. + fn cvt_msg( + read: &mut usize, + length: &mut usize, + msg: &c::cmsghdr, + ) -> Option<RecvAncillaryMessage<'buf>> { + unsafe { + // Advance the `read` pointer. + let msg_len = msg.cmsg_len as usize; + *read += msg_len; + *length -= msg_len; + + // Get a pointer to the payload. + let payload = c::CMSG_DATA(msg); + let payload_len = msg.cmsg_len as usize - c::CMSG_LEN(0) as usize; + + // Get a mutable slice of the payload. + let payload: &'buf mut [u8] = slice::from_raw_parts_mut(payload, payload_len); + + // Determine what type it is. + let (level, msg_type) = (msg.cmsg_level, msg.cmsg_type); + match (level as _, msg_type as _) { + (c::SOL_SOCKET, c::SCM_RIGHTS) => { + // Create an iterator that reads out the file descriptors. + let fds = AncillaryIter::new(payload); + + Some(RecvAncillaryMessage::ScmRights(fds)) + } + #[cfg(linux_kernel)] + (c::SOL_SOCKET, c::SCM_CREDENTIALS) => { + if payload_len >= size_of::<UCred>() { + let ucred = payload.as_ptr().cast::<UCred>().read_unaligned(); + Some(RecvAncillaryMessage::ScmCredentials(ucred)) + } else { + None + } + } + _ => None, + } + } + } +} + +impl<'buf> Iterator for AncillaryDrain<'buf> { + type Item = RecvAncillaryMessage<'buf>; + + fn next(&mut self) -> Option<Self::Item> { + let read = &mut self.read; + let length = &mut self.length; + self.messages.find_map(|ev| Self::cvt_msg(read, length, ev)) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let (_, max) = self.messages.size_hint(); + (0, max) + } + + fn fold<B, F>(self, init: B, f: F) -> B + where + Self: Sized, + F: FnMut(B, Self::Item) -> B, + { + let read = self.read; + let length = self.length; + self.messages + .filter_map(|ev| Self::cvt_msg(read, length, ev)) + .fold(init, f) + } + + fn count(self) -> usize { + let read = self.read; + let length = self.length; + self.messages + .filter_map(|ev| Self::cvt_msg(read, length, ev)) + .count() + } + + fn last(self) -> Option<Self::Item> + where + Self: Sized, + { + let read = self.read; + let length = self.length; + self.messages + .filter_map(|ev| Self::cvt_msg(read, length, ev)) + .last() + } + + fn collect<B: FromIterator<Self::Item>>(self) -> B + where + Self: Sized, + { + let read = self.read; + let length = self.length; + self.messages + .filter_map(|ev| Self::cvt_msg(read, length, ev)) + .collect() + } +} + +impl FusedIterator for AncillaryDrain<'_> {} + +/// `sendmsg(msghdr)`—Sends a message on a socket. +/// +/// # References +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendmsg.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendmsg.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendmsg.2.html +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendmsg&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendmsg.2 +/// [OpenBSD]: https://man.openbsd.org/sendmsg.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendmsg§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendmsg +#[inline] +pub fn sendmsg( + socket: impl AsFd, + iov: &[IoSlice<'_>], + control: &mut SendAncillaryBuffer<'_, '_, '_>, + flags: SendFlags, +) -> io::Result<usize> { + backend::net::syscalls::sendmsg(socket.as_fd(), iov, control, flags) +} + +/// `sendmsg(msghdr)`—Sends a message on a socket to a specific IPv4 address. +/// +/// # References +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendmsg.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendmsg.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendmsg.2.html +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendmsg&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendmsg.2 +/// [OpenBSD]: https://man.openbsd.org/sendmsg.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendmsg§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendmsg +#[inline] +pub fn sendmsg_v4( + socket: impl AsFd, + addr: &SocketAddrV4, + iov: &[IoSlice<'_>], + control: &mut SendAncillaryBuffer<'_, '_, '_>, + flags: SendFlags, +) -> io::Result<usize> { + backend::net::syscalls::sendmsg_v4(socket.as_fd(), addr, iov, control, flags) +} + +/// `sendmsg(msghdr)`—Sends a message on a socket to a specific IPv6 address. +/// +/// # References +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendmsg.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendmsg.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendmsg.2.html +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendmsg&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendmsg.2 +/// [OpenBSD]: https://man.openbsd.org/sendmsg.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendmsg§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendmsg +#[inline] +pub fn sendmsg_v6( + socket: impl AsFd, + addr: &SocketAddrV6, + iov: &[IoSlice<'_>], + control: &mut SendAncillaryBuffer<'_, '_, '_>, + flags: SendFlags, +) -> io::Result<usize> { + backend::net::syscalls::sendmsg_v6(socket.as_fd(), addr, iov, control, flags) +} + +/// `sendmsg(msghdr)`—Sends a message on a socket to a specific Unix-domain +/// address. +/// +/// # References +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendmsg.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendmsg.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendmsg.2.html +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendmsg&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendmsg.2 +/// [OpenBSD]: https://man.openbsd.org/sendmsg.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendmsg§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendmsg +#[inline] +#[cfg(unix)] +pub fn sendmsg_unix( + socket: impl AsFd, + addr: &super::SocketAddrUnix, + iov: &[IoSlice<'_>], + control: &mut SendAncillaryBuffer<'_, '_, '_>, + flags: SendFlags, +) -> io::Result<usize> { + backend::net::syscalls::sendmsg_unix(socket.as_fd(), addr, iov, control, flags) +} + +/// `sendmsg(msghdr)`—Sends a message on a socket to a specific address. +/// +/// # References +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sendmsg.html +/// [Linux]: https://man7.org/linux/man-pages/man2/sendmsg.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/sendmsg.2.html +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=sendmsg&sektion=2 +/// [NetBSD]: https://man.netbsd.org/sendmsg.2 +/// [OpenBSD]: https://man.openbsd.org/sendmsg.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=sendmsg§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/sendmsg +#[inline] +pub fn sendmsg_any( + socket: impl AsFd, + addr: Option<&SocketAddrAny>, + iov: &[IoSlice<'_>], + control: &mut SendAncillaryBuffer<'_, '_, '_>, + flags: SendFlags, +) -> io::Result<usize> { + match addr { + None => backend::net::syscalls::sendmsg(socket.as_fd(), iov, control, flags), + Some(SocketAddrAny::V4(addr)) => { + backend::net::syscalls::sendmsg_v4(socket.as_fd(), addr, iov, control, flags) + } + Some(SocketAddrAny::V6(addr)) => { + backend::net::syscalls::sendmsg_v6(socket.as_fd(), addr, iov, control, flags) + } + #[cfg(unix)] + Some(SocketAddrAny::Unix(addr)) => { + backend::net::syscalls::sendmsg_unix(socket.as_fd(), addr, iov, control, flags) + } + } +} + +/// `recvmsg(msghdr)`—Receives a message from a socket. +/// +/// # References +/// - [POSIX] +/// - [Linux] +/// - [Apple] +/// - [FreeBSD] +/// - [NetBSD] +/// - [OpenBSD] +/// - [DragonFly BSD] +/// - [illumos] +/// +/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/recvmsg.html +/// [Linux]: https://man7.org/linux/man-pages/man2/recvmsg.2.html +/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/recvmsg.2.html +/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=recvmsg&sektion=2 +/// [NetBSD]: https://man.netbsd.org/recvmsg.2 +/// [OpenBSD]: https://man.openbsd.org/recvmsg.2 +/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=recvmsg§ion=2 +/// [illumos]: https://illumos.org/man/3SOCKET/recvmsg +#[inline] +pub fn recvmsg( + socket: impl AsFd, + iov: &mut [IoSliceMut<'_>], + control: &mut RecvAncillaryBuffer<'_>, + flags: RecvFlags, +) -> io::Result<RecvMsgReturn> { + backend::net::syscalls::recvmsg(socket.as_fd(), iov, control, flags) +} + +/// The result of a successful [`recvmsg`] call. +pub struct RecvMsgReturn { + /// The number of bytes received. + pub bytes: usize, + + /// The flags received. + pub flags: RecvFlags, + + /// The address of the socket we received from, if any. + pub address: Option<SocketAddrAny>, +} + +/// An iterator over data in an ancillary buffer. +pub struct AncillaryIter<'data, T> { + /// The data we're iterating over. + data: &'data mut [u8], + + /// The raw data we're removing. + _marker: PhantomData<T>, +} + +impl<'data, T> AncillaryIter<'data, T> { + /// Create a new iterator over data in an ancillary buffer. + /// + /// # Safety + /// + /// The buffer must contain valid ancillary data. + unsafe fn new(data: &'data mut [u8]) -> Self { + assert_eq!(data.len() % size_of::<T>(), 0); + + Self { + data, + _marker: PhantomData, + } + } +} + +impl<'data, T> Drop for AncillaryIter<'data, T> { + fn drop(&mut self) { + self.for_each(drop); + } +} + +impl<T> Iterator for AncillaryIter<'_, T> { + type Item = T; + + fn next(&mut self) -> Option<Self::Item> { + // See if there is a next item. + if self.data.len() < size_of::<T>() { + return None; + } + + // Get the next item. + let item = unsafe { self.data.as_ptr().cast::<T>().read_unaligned() }; + + // Move forward. + let data = take(&mut self.data); + self.data = &mut data[size_of::<T>()..]; + + Some(item) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let len = self.len(); + (len, Some(len)) + } + + fn count(self) -> usize { + self.len() + } + + fn last(mut self) -> Option<Self::Item> { + self.next_back() + } +} + +impl<T> FusedIterator for AncillaryIter<'_, T> {} + +impl<T> ExactSizeIterator for AncillaryIter<'_, T> { + fn len(&self) -> usize { + self.data.len() / size_of::<T>() + } +} + +impl<T> DoubleEndedIterator for AncillaryIter<'_, T> { + fn next_back(&mut self) -> Option<Self::Item> { + // See if there is a next item. + if self.data.len() < size_of::<T>() { + return None; + } + + // Get the next item. + let item = unsafe { + let ptr = self.data.as_ptr().add(self.data.len() - size_of::<T>()); + ptr.cast::<T>().read_unaligned() + }; + + // Move forward. + let len = self.data.len(); + let data = take(&mut self.data); + self.data = &mut data[..len - size_of::<T>()]; + + Some(item) + } +} + +mod messages { + use crate::backend::c; + use crate::backend::net::msghdr; + use core::iter::FusedIterator; + use core::marker::PhantomData; + use core::ptr::NonNull; + + /// An iterator over the messages in an ancillary buffer. + pub(super) struct Messages<'buf> { + /// The message header we're using to iterate over the messages. + msghdr: c::msghdr, + + /// The current pointer to the next message header to return. + /// + /// This has a lifetime of `'buf`. + header: Option<NonNull<c::cmsghdr>>, + + /// Capture the original lifetime of the buffer. + _buffer: PhantomData<&'buf mut [u8]>, + } + + impl<'buf> Messages<'buf> { + /// Create a new iterator over messages from a byte buffer. + pub(super) fn new(buf: &'buf mut [u8]) -> Self { + let msghdr = { + let mut h = msghdr::zero_msghdr(); + h.msg_control = buf.as_mut_ptr().cast(); + h.msg_controllen = buf.len().try_into().expect("buffer too large for msghdr"); + h + }; + + // Get the first header. + let header = NonNull::new(unsafe { c::CMSG_FIRSTHDR(&msghdr) }); + + Self { + msghdr, + header, + _buffer: PhantomData, + } + } + } + + impl<'a> Iterator for Messages<'a> { + type Item = &'a mut c::cmsghdr; + + #[inline] + fn next(&mut self) -> Option<Self::Item> { + // Get the current header. + let header = self.header?; + + // Get the next header. + self.header = NonNull::new(unsafe { c::CMSG_NXTHDR(&self.msghdr, header.as_ptr()) }); + + // If the headers are equal, we're done. + if Some(header) == self.header { + self.header = None; + } + + // SAFETY: The lifetime of `header` is tied to this. + Some(unsafe { &mut *header.as_ptr() }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.header.is_some() { + // The remaining buffer *could* be filled with zero-length + // messages. + let max_size = unsafe { c::CMSG_LEN(0) } as usize; + let remaining_count = self.msghdr.msg_controllen as usize / max_size; + (1, Some(remaining_count)) + } else { + (0, Some(0)) + } + } + } + + impl FusedIterator for Messages<'_> {} +} |