Overhaul the net types. (#691)

* Overhaul the `net` types.

 - Factor out per-backend src/backend/*/net/types.rs into a common
   src/net/types.rs source file.

 - Add `NETLINK_*`, `ETH_P_*`, and other protocol constants.

 - Remove `Protocol::default()` and change `socket`'s protocol argument
   to be `Option<Protocol>`, to better model how `0` means to use the
   default protocol.

Fixes #688.

* Add more documentation links.

* Encode the `ETH_P_*` constants as 16-bit big-endian.

Author: sunfishcode

Cargo.toml

@@ -38,7 +38,7 @@ once_cell = { version = "1.5.2", optional = true }
 # libc backend can be selected via adding `--cfg=rustix_use_libc` to
 # `RUSTFLAGS` or enabling the `use-libc` cargo feature.
 [target.'cfg(all(not(rustix_use_libc), not(miri), target_os = "linux", target_endian = "little", any(target_arch = "arm", all(target_arch = "aarch64", target_pointer_width = "64"), target_arch = "powerpc64", target_arch = "riscv64", target_arch = "mips", target_arch = "mips64", target_arch = "x86", all(target_arch = "x86_64", target_pointer_width = "64"))))'.dependencies]
-linux-raw-sys = { version = "0.4.1", default-features = false, features = ["general", "errno", "ioctl", "no_std"] }
+linux-raw-sys = { version = "0.4.2", default-features = false, features = ["general", "errno", "ioctl", "no_std"] }
 libc_errno = { package = "errno", version = "0.3.1", default-features = false, optional = true }
 libc = { version = "0.2.144", features = ["extra_traits"], optional = true }
 
@@ -55,7 +55,7 @@ libc = { version = "0.2.144", features = ["extra_traits"] }
 # Some syscalls do not have libc wrappers, such as in `io_uring`. For these,
 # the libc backend uses the linux-raw-sys ABI and `libc::syscall`.
 [target.'cfg(all(any(target_os = "android", target_os = "linux"), any(rustix_use_libc, miri, not(all(target_os = "linux", target_endian = "little", any(target_arch = "arm", all(target_arch = "aarch64", target_pointer_width = "64"), target_arch = "powerpc64", target_arch = "riscv64", target_arch = "mips", target_arch = "mips64", target_arch = "x86", all(target_arch = "x86_64", target_pointer_width = "64")))))))'.dependencies]
-linux-raw-sys = { version = "0.4.1", default-features = false, features = ["general", "ioctl", "no_std"] }
+linux-raw-sys = { version = "0.4.2", default-features = false, features = ["general", "ioctl", "no_std"] }
 
 # For the libc backend on Windows, use the Winsock2 API in windows-sys.
 [target.'cfg(windows)'.dependencies.windows-sys]
@@ -148,7 +148,7 @@ fs = []
 io_uring = ["fs", "net", "linux-raw-sys/io_uring"]
 
 # Enable `rustix::net::*`.
-net = ["linux-raw-sys/net"]
+net = ["linux-raw-sys/net", "linux-raw-sys/netlink", "linux-raw-sys/if_ether"]
 
 # Enable `rustix::thread::*`.
 thread = ["linux-raw-sys/prctl"]

src/backend/libc/c.rs

@@ -12,6 +12,56 @@ pub(crate) const PROC_SUPER_MAGIC: u32 = 0x0000_9fa0;
 #[cfg(all(linux_kernel, target_env = "musl"))]
 pub(crate) const NFS_SUPER_MAGIC: u32 = 0x0000_6969;
 
+// Submitted upstream in https://github.com/rust-lang/libc/pull/3272.
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const IPPROTO_ETHERNET: c_int = linux_raw_sys::net::IPPROTO_ETHERNET as _;
+
+// TODO: Upstream these.
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_TSN: c_int = linux_raw_sys::if_ether::ETH_P_TSN as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_ERSPAN2: c_int = linux_raw_sys::if_ether::ETH_P_ERSPAN2 as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_ERSPAN: c_int = linux_raw_sys::if_ether::ETH_P_ERSPAN as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_PROFINET: c_int = linux_raw_sys::if_ether::ETH_P_PROFINET as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_REALTEK: c_int = linux_raw_sys::if_ether::ETH_P_REALTEK as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_ETHERCAT: c_int = linux_raw_sys::if_ether::ETH_P_ETHERCAT as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_PREAUTH: c_int = linux_raw_sys::if_ether::ETH_P_PREAUTH as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_LLDP: c_int = linux_raw_sys::if_ether::ETH_P_LLDP as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_MRP: c_int = linux_raw_sys::if_ether::ETH_P_MRP as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_NCSI: c_int = linux_raw_sys::if_ether::ETH_P_NCSI as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_CFM: c_int = linux_raw_sys::if_ether::ETH_P_CFM as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_IBOE: c_int = linux_raw_sys::if_ether::ETH_P_IBOE as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_HSR: c_int = linux_raw_sys::if_ether::ETH_P_HSR as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_NSH: c_int = linux_raw_sys::if_ether::ETH_P_NSH as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_DSA_8021Q: c_int = linux_raw_sys::if_ether::ETH_P_DSA_8021Q as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_DSA_A5PSW: c_int = linux_raw_sys::if_ether::ETH_P_DSA_A5PSW as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_IFE: c_int = linux_raw_sys::if_ether::ETH_P_IFE as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_CAN: c_int = linux_raw_sys::if_ether::ETH_P_CAN as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_CANXL: c_int = linux_raw_sys::if_ether::ETH_P_CANXL as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_XDSA: c_int = linux_raw_sys::if_ether::ETH_P_XDSA as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_MAP: c_int = linux_raw_sys::if_ether::ETH_P_MAP as _;
+#[cfg(all(linux_kernel, feature = "net"))]
+pub(crate) const ETH_P_MCTP: c_int = linux_raw_sys::if_ether::ETH_P_MCTP as _;
+
 #[cfg(all(
     linux_kernel,
     any(

src/backend/libc/event/epoll.rs

@@ -13,14 +13,13 @@
 //! use rustix::fd::AsFd;
 //! use rustix::io::{ioctl_fionbio, read, write};
 //! use rustix::net::{
-//!     accept, bind_v4, listen, socket, AddressFamily, Ipv4Addr, Protocol, SocketAddrV4,
-//!     SocketType,
+//!     accept, bind_v4, listen, socket, AddressFamily, Ipv4Addr, SocketAddrV4, SocketType,
 //! };
 //! use std::collections::HashMap;
 //! use std::os::unix::io::AsRawFd;
 //!
 //! // Create a socket and listen on it.
-//! let listen_sock = socket(AddressFamily::INET, SocketType::STREAM, Protocol::default())?;
+//! let listen_sock = socket(AddressFamily::INET, SocketType::STREAM, None)?;
 //! bind_v4(&listen_sock, &SocketAddrV4::new(Ipv4Addr::LOCALHOST, 0))?;
 //! listen(&listen_sock, 1)?;
 //!

src/backend/libc/net/mod.rs

@@ -5,5 +5,4 @@ pub(crate) mod msghdr;
 pub(crate) mod read_sockaddr;
 pub(crate) mod send_recv;
 pub(crate) mod syscalls;
-pub(crate) mod types;
 pub(crate) mod write_sockaddr;

src/backend/libc/net/syscalls.rs

@@ -20,8 +20,8 @@ use {
 use {
     super::read_sockaddr::{initialize_family_to_unspec, maybe_read_sockaddr_os, read_sockaddr_os},
     super::send_recv::{RecvFlags, SendFlags},
-    super::types::{AddressFamily, Protocol, Shutdown, SocketFlags, SocketType},
     super::write_sockaddr::{encode_sockaddr_v4, encode_sockaddr_v6},
+    crate::net::{AddressFamily, Protocol, Shutdown, SocketFlags, SocketType},
     core::ptr::null_mut,
 };
 
@@ -142,13 +142,17 @@ pub(crate) fn sendto_unix(
 pub(crate) fn socket(
     domain: AddressFamily,
     type_: SocketType,
-    protocol: Protocol,
+    protocol: Option<Protocol>,
 ) -> io::Result<OwnedFd> {
+    let raw_protocol = match protocol {
+        Some(p) => p.0.get(),
+        None => 0,
+    };
     unsafe {
         ret_owned_fd(c::socket(
             domain.0 as c::c_int,
             type_.0 as c::c_int,
-            protocol.0,
+            raw_protocol as c::c_int,
         ))
     }
 }
@@ -158,13 +162,17 @@ pub(crate) fn socket_with(
     domain: AddressFamily,
     type_: SocketType,
     flags: SocketFlags,
-    protocol: Protocol,
+    protocol: Option<Protocol>,
 ) -> io::Result<OwnedFd> {
+    let raw_protocol = match protocol {
+        Some(p) => p.0.get(),
+        None => 0,
+    };
     unsafe {
         ret_owned_fd(c::socket(
             domain.0 as c::c_int,
-            type_.0 as c::c_int | flags.bits(),
-            protocol.0,
+            (type_.0 | flags.bits()) as c::c_int,
+            raw_protocol as c::c_int,
         ))
     }
 }
@@ -339,7 +347,7 @@ pub(crate) fn accept_with(sockfd: BorrowedFd<'_>, flags: SocketFlags) -> io::Res
             borrowed_fd(sockfd),
             null_mut(),
             null_mut(),
-            flags.bits(),
+            flags.bits() as c::c_int,
         ))?;
         Ok(owned_fd)
     }
@@ -380,7 +388,7 @@ pub(crate) fn acceptfrom_with(
             borrowed_fd(sockfd),
             storage.as_mut_ptr().cast(),
             &mut len,
-            flags.bits(),
+            flags.bits() as c::c_int,
         ))?;
         Ok((
             owned_fd,
@@ -447,14 +455,18 @@ pub(crate) fn socketpair(
     domain: AddressFamily,
     type_: SocketType,
     flags: SocketFlags,
-    protocol: Protocol,
+    protocol: Option<Protocol>,
 ) -> io::Result<(OwnedFd, OwnedFd)> {
+    let raw_protocol = match protocol {
+        Some(p) => p.0.get(),
+        None => 0,
+    };
     unsafe {
         let mut fds = MaybeUninit::<[OwnedFd; 2]>::uninit();
         ret(c::socketpair(
             c::c_int::from(domain.0),
-            type_.0 as c::c_int | flags.bits(),
-            protocol.0,
+            (type_.0 | flags.bits()) as c::c_int,
+            raw_protocol as c::c_int,
             fds.as_mut_ptr().cast::<c::c_int>(),
         ))?;