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

   1 use crate::cmp;
   2 use crate::ffi::CStr;
   3 use crate::io::{self, IoSlice, IoSliceMut};
   4 use crate::mem;
   5 use crate::net::{Shutdown, SocketAddr};
   6 use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
   7 use crate::str;
   8 use crate::sys::fd::FileDesc;
   9 use crate::sys_common::net::{getsockopt, setsockopt, sockaddr_to_addr};
  10 use crate::sys_common::{AsInner, FromInner, IntoInner};
  11 use crate::time::{Duration, Instant};
  12
  13 use libc::{c_int, c_void, size_t, sockaddr, socklen_t, MSG_PEEK};
  14
  15 cfg_if::cfg_if! {
  16     if #[cfg(target_vendor = "apple")] {
  17         use libc::SO_LINGER_SEC as SO_LINGER;
  18     } else {
  19         use libc::SO_LINGER;
  20     }
  21 }
  22
  23 pub use crate::sys::{cvt, cvt_r};
  24
  25 #[allow(unused_extern_crates)]
  26 pub extern crate libc as netc;
  27
  28 pub type wrlen_t = size_t;
  29
  30 pub struct Socket(FileDesc);
  31
  32 pub fn init() {}
  33
  34 pub fn cvt_gai(err: c_int) -> io::Result<()> {
  35     if err == 0 {
  36         return Ok(());
  37     }
  38
  39     // We may need to trigger a glibc workaround. See on_resolver_failure() for details.
  40     on_resolver_failure();
  41
  42     #[cfg(not(target_os = "espidf"))]
  43     if err == libc::EAI_SYSTEM {
  44         return Err(io::Error::last_os_error());
  45     }
  46
  47     #[cfg(not(target_os = "espidf"))]
  48     let detail = unsafe {
  49         str::from_utf8(CStr::from_ptr(libc::gai_strerror(err)).to_bytes()).unwrap().to_owned()
  50     };
  51
  52     #[cfg(target_os = "espidf")]
  53     let detail = "";
  54
  55     Err(io::Error::new(
  56         io::ErrorKind::Uncategorized,
  57         &format!("failed to lookup address information: {detail}")[..],
  58     ))
  59 }
  60
  61 impl Socket {
  62     pub fn new(addr: &SocketAddr, ty: c_int) -> io::Result<Socket> {
  63         let fam = match *addr {
  64             SocketAddr::V4(..) => libc::AF_INET,
  65             SocketAddr::V6(..) => libc::AF_INET6,
  66         };
  67         Socket::new_raw(fam, ty)
  68     }
  69
  70     pub fn new_raw(fam: c_int, ty: c_int) -> io::Result<Socket> {
  71         unsafe {
  72             cfg_if::cfg_if! {
  73                 if #[cfg(any(
  74                     target_os = "android",
  75                     target_os = "dragonfly",
  76                     target_os = "freebsd",
  77                     target_os = "illumos",
  78                     target_os = "linux",
  79                     target_os = "netbsd",
  80                     target_os = "openbsd",
  81                 ))] {
  82                     // On platforms that support it we pass the SOCK_CLOEXEC
  83                     // flag to atomically create the socket and set it as
  84                     // CLOEXEC. On Linux this was added in 2.6.27.
  85                     let fd = cvt(libc::socket(fam, ty | libc::SOCK_CLOEXEC, 0))?;
  86                     Ok(Socket(FileDesc::from_raw_fd(fd)))
  87                 } else {
  88                     let fd = cvt(libc::socket(fam, ty, 0))?;
  89                     let fd = FileDesc::from_raw_fd(fd);
  90                     fd.set_cloexec()?;
  91                     let socket = Socket(fd);
  92
  93                     // macOS and iOS use `SO_NOSIGPIPE` as a `setsockopt`
  94                     // flag to disable `SIGPIPE` emission on socket.
  95                     #[cfg(target_vendor = "apple")]
  96                     setsockopt(&socket, libc::SOL_SOCKET, libc::SO_NOSIGPIPE, 1)?;
  97
  98                     Ok(socket)
  99                 }
 100             }
 101         }
 102     }
 103
 104     #[cfg(not(target_os = "vxworks"))]
 105     pub fn new_pair(fam: c_int, ty: c_int) -> io::Result<(Socket, Socket)> {
 106         unsafe {
 107             let mut fds = [0, 0];
 108
 109             cfg_if::cfg_if! {
 110                 if #[cfg(any(
 111                     target_os = "android",
 112                     target_os = "dragonfly",
 113                     target_os = "freebsd",
 114                     target_os = "illumos",
 115                     target_os = "linux",
 116                     target_os = "netbsd",
 117                     target_os = "openbsd",
 118                 ))] {
 119                     // Like above, set cloexec atomically
 120                     cvt(libc::socketpair(fam, ty | libc::SOCK_CLOEXEC, 0, fds.as_mut_ptr()))?;
 121                     Ok((Socket(FileDesc::from_raw_fd(fds[0])), Socket(FileDesc::from_raw_fd(fds[1]))))
 122                 } else {
 123                     cvt(libc::socketpair(fam, ty, 0, fds.as_mut_ptr()))?;
 124                     let a = FileDesc::from_raw_fd(fds[0]);
 125                     let b = FileDesc::from_raw_fd(fds[1]);
 126                     a.set_cloexec()?;
 127                     b.set_cloexec()?;
 128                     Ok((Socket(a), Socket(b)))
 129                 }
 130             }
 131         }
 132     }
 133
 134     #[cfg(target_os = "vxworks")]
 135     pub fn new_pair(_fam: c_int, _ty: c_int) -> io::Result<(Socket, Socket)> {
 136         unimplemented!()
 137     }
 138
 139     pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Result<()> {
 140         self.set_nonblocking(true)?;
 141         let r = unsafe {
 142             let (addrp, len) = addr.into_inner();
 143             cvt(libc::connect(self.as_raw_fd(), addrp, len))
 144         };
 145         self.set_nonblocking(false)?;
 146
 147         match r {
 148             Ok(_) => return Ok(()),
 149             // there's no ErrorKind for EINPROGRESS :(
 150             Err(ref e) if e.raw_os_error() == Some(libc::EINPROGRESS) => {}
 151             Err(e) => return Err(e),
 152         }
 153
 154         let mut pollfd = libc::pollfd { fd: self.as_raw_fd(), events: libc::POLLOUT, revents: 0 };
 155
 156         if timeout.as_secs() == 0 && timeout.subsec_nanos() == 0 {
 157             return Err(io::const_io_error!(
 158                 io::ErrorKind::InvalidInput,
 159                 "cannot set a 0 duration timeout",
 160             ));
 161         }
 162
 163         let start = Instant::now();
 164
 165         loop {
 166             let elapsed = start.elapsed();
 167             if elapsed >= timeout {
 168                 return Err(io::const_io_error!(io::ErrorKind::TimedOut, "connection timed out"));
 169             }
 170
 171             let timeout = timeout - elapsed;
 172             let mut timeout = timeout
 173                 .as_secs()
 174                 .saturating_mul(1_000)
 175                 .saturating_add(timeout.subsec_nanos() as u64 / 1_000_000);
 176             if timeout == 0 {
 177                 timeout = 1;
 178             }
 179
 180             let timeout = cmp::min(timeout, c_int::MAX as u64) as c_int;
 181
 182             match unsafe { libc::poll(&mut pollfd, 1, timeout) } {
 183                 -1 => {
 184                     let err = io::Error::last_os_error();
 185                     if err.kind() != io::ErrorKind::Interrupted {
 186                         return Err(err);
 187                     }
 188                 }
 189                 0 => {}
 190                 _ => {
 191                     // linux returns POLLOUT|POLLERR|POLLHUP for refused connections (!), so look
 192                     // for POLLHUP rather than read readiness
 193                     if pollfd.revents & libc::POLLHUP != 0 {
 194                         let e = self.take_error()?.unwrap_or_else(|| {
 195                             io::const_io_error!(
 196                                 io::ErrorKind::Uncategorized,
 197                                 "no error set after POLLHUP",
 198                             )
 199                         });
 200                         return Err(e);
 201                     }
 202
 203                     return Ok(());
 204                 }
 205             }
 206         }
 207     }
 208
 209     pub fn accept(&self, storage: *mut sockaddr, len: *mut socklen_t) -> io::Result<Socket> {
 210         // Unfortunately the only known way right now to accept a socket and
 211         // atomically set the CLOEXEC flag is to use the `accept4` syscall on
 212         // platforms that support it. On Linux, this was added in 2.6.28,
 213         // glibc 2.10 and musl 0.9.5.
 214         cfg_if::cfg_if! {
 215             if #[cfg(any(
 216                 target_os = "android",
 217                 target_os = "dragonfly",
 218                 target_os = "freebsd",
 219                 target_os = "illumos",
 220                 target_os = "linux",
 221                 target_os = "netbsd",
 222                 target_os = "openbsd",
 223             ))] {
 224                 unsafe {
 225                     let fd = cvt_r(|| libc::accept4(self.as_raw_fd(), storage, len, libc::SOCK_CLOEXEC))?;
 226                     Ok(Socket(FileDesc::from_raw_fd(fd)))
 227                 }
 228             } else {
 229                 unsafe {
 230                     let fd = cvt_r(|| libc::accept(self.as_raw_fd(), storage, len))?;
 231                     let fd = FileDesc::from_raw_fd(fd);
 232                     fd.set_cloexec()?;
 233                     Ok(Socket(fd))
 234                 }
 235             }
 236         }
 237     }
 238
 239     pub fn duplicate(&self) -> io::Result<Socket> {
 240         self.0.duplicate().map(Socket)
 241     }
 242
 243     fn recv_with_flags(&self, buf: &mut [u8], flags: c_int) -> io::Result<usize> {
 244         let ret = cvt(unsafe {
 245             libc::recv(self.as_raw_fd(), buf.as_mut_ptr() as *mut c_void, buf.len(), flags)
 246         })?;
 247         Ok(ret as usize)
 248     }
 249
 250     pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
 251         self.recv_with_flags(buf, 0)
 252     }
 253
 254     pub fn peek(&self, buf: &mut [u8]) -> io::Result<usize> {
 255         self.recv_with_flags(buf, MSG_PEEK)
 256     }
 257
 258     pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
 259         self.0.read_vectored(bufs)
 260     }
 261
 262     #[inline]
 263     pub fn is_read_vectored(&self) -> bool {
 264         self.0.is_read_vectored()
 265     }
 266
 267     fn recv_from_with_flags(
 268         &self,
 269         buf: &mut [u8],
 270         flags: c_int,
 271     ) -> io::Result<(usize, SocketAddr)> {
 272         let mut storage: libc::sockaddr_storage = unsafe { mem::zeroed() };
 273         let mut addrlen = mem::size_of_val(&storage) as libc::socklen_t;
 274
 275         let n = cvt(unsafe {
 276             libc::recvfrom(
 277                 self.as_raw_fd(),
 278                 buf.as_mut_ptr() as *mut c_void,
 279                 buf.len(),
 280                 flags,
 281                 &mut storage as *mut _ as *mut _,
 282                 &mut addrlen,
 283             )
 284         })?;
 285         Ok((n as usize, sockaddr_to_addr(&storage, addrlen as usize)?))
 286     }
 287
 288     pub fn recv_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
 289         self.recv_from_with_flags(buf, 0)
 290     }
 291
 292     #[cfg(any(
 293         target_os = "android",
 294         target_os = "dragonfly",
 295         target_os = "emscripten",
 296         target_os = "freebsd",
 297         target_os = "linux",
 298         target_os = "netbsd",
 299         target_os = "openbsd",
 300     ))]
 301     pub fn recv_msg(&self, msg: &mut libc::msghdr) -> io::Result<usize> {
 302         let n = cvt(unsafe { libc::recvmsg(self.as_raw_fd(), msg, libc::MSG_CMSG_CLOEXEC) })?;
 303         Ok(n as usize)
 304     }
 305
 306     pub fn peek_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
 307         self.recv_from_with_flags(buf, MSG_PEEK)
 308     }
 309
 310     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
 311         self.0.write(buf)
 312     }
 313
 314     pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
 315         self.0.write_vectored(bufs)
 316     }
 317
 318     #[inline]
 319     pub fn is_write_vectored(&self) -> bool {
 320         self.0.is_write_vectored()
 321     }
 322
 323     #[cfg(any(
 324         target_os = "android",
 325         target_os = "dragonfly",
 326         target_os = "emscripten",
 327         target_os = "freebsd",
 328         target_os = "linux",
 329         target_os = "netbsd",
 330         target_os = "openbsd",
 331     ))]
 332     pub fn send_msg(&self, msg: &mut libc::msghdr) -> io::Result<usize> {
 333         let n = cvt(unsafe { libc::sendmsg(self.as_raw_fd(), msg, 0) })?;
 334         Ok(n as usize)
 335     }
 336
 337     pub fn set_timeout(&self, dur: Option<Duration>, kind: libc::c_int) -> io::Result<()> {
 338         let timeout = match dur {
 339             Some(dur) => {
 340                 if dur.as_secs() == 0 && dur.subsec_nanos() == 0 {
 341                     return Err(io::const_io_error!(
 342                         io::ErrorKind::InvalidInput,
 343                         "cannot set a 0 duration timeout",
 344                     ));
 345                 }
 346
 347                 let secs = if dur.as_secs() > libc::time_t::MAX as u64 {
 348                     libc::time_t::MAX
 349                 } else {
 350                     dur.as_secs() as libc::time_t
 351                 };
 352                 let mut timeout = libc::timeval {
 353                     tv_sec: secs,
 354                     tv_usec: dur.subsec_micros() as libc::suseconds_t,
 355                 };
 356                 if timeout.tv_sec == 0 && timeout.tv_usec == 0 {
 357                     timeout.tv_usec = 1;
 358                 }
 359                 timeout
 360             }
 361             None => libc::timeval { tv_sec: 0, tv_usec: 0 },
 362         };
 363         setsockopt(self, libc::SOL_SOCKET, kind, timeout)
 364     }
 365
 366     pub fn timeout(&self, kind: libc::c_int) -> io::Result<Option<Duration>> {
 367         let raw: libc::timeval = getsockopt(self, libc::SOL_SOCKET, kind)?;
 368         if raw.tv_sec == 0 && raw.tv_usec == 0 {
 369             Ok(None)
 370         } else {
 371             let sec = raw.tv_sec as u64;
 372             let nsec = (raw.tv_usec as u32) * 1000;
 373             Ok(Some(Duration::new(sec, nsec)))
 374         }
 375     }
 376
 377     pub fn shutdown(&self, how: Shutdown) -> io::Result<()> {
 378         let how = match how {
 379             Shutdown::Write => libc::SHUT_WR,
 380             Shutdown::Read => libc::SHUT_RD,
 381             Shutdown::Both => libc::SHUT_RDWR,
 382         };
 383         cvt(unsafe { libc::shutdown(self.as_raw_fd(), how) })?;
 384         Ok(())
 385     }
 386
 387     pub fn set_linger(&self, linger: Option<Duration>) -> io::Result<()> {
 388         let linger = libc::linger {
 389             l_onoff: linger.is_some() as libc::c_int,
 390             l_linger: linger.unwrap_or_default().as_secs() as libc::c_int,
 391         };
 392
 393         setsockopt(self, libc::SOL_SOCKET, SO_LINGER, linger)
 394     }
 395
 396     pub fn linger(&self) -> io::Result<Option<Duration>> {
 397         let val: libc::linger = getsockopt(self, libc::SOL_SOCKET, SO_LINGER)?;
 398
 399         Ok((val.l_onoff != 0).then(|| Duration::from_secs(val.l_linger as u64)))
 400     }
 401
 402     pub fn set_nodelay(&self, nodelay: bool) -> io::Result<()> {
 403         setsockopt(self, libc::IPPROTO_TCP, libc::TCP_NODELAY, nodelay as c_int)
 404     }
 405
 406     pub fn nodelay(&self) -> io::Result<bool> {
 407         let raw: c_int = getsockopt(self, libc::IPPROTO_TCP, libc::TCP_NODELAY)?;
 408         Ok(raw != 0)
 409     }
 410
 411     #[cfg(any(target_os = "android", target_os = "linux",))]
 412     pub fn set_passcred(&self, passcred: bool) -> io::Result<()> {
 413         setsockopt(self, libc::SOL_SOCKET, libc::SO_PASSCRED, passcred as libc::c_int)
 414     }
 415
 416     #[cfg(any(target_os = "android", target_os = "linux",))]
 417     pub fn passcred(&self) -> io::Result<bool> {
 418         let passcred: libc::c_int = getsockopt(self, libc::SOL_SOCKET, libc::SO_PASSCRED)?;
 419         Ok(passcred != 0)
 420     }
 421
 422     #[cfg(target_os = "netbsd")]
 423     pub fn set_passcred(&self, passcred: bool) -> io::Result<()> {
 424         setsockopt(self, 0 as libc::c_int, libc::LOCAL_CREDS, passcred as libc::c_int)
 425     }
 426
 427     #[cfg(target_os = "netbsd")]
 428     pub fn passcred(&self) -> io::Result<bool> {
 429         let passcred: libc::c_int = getsockopt(self, 0 as libc::c_int, libc::LOCAL_CREDS)?;
 430         Ok(passcred != 0)
 431     }
 432
 433     #[cfg(not(any(target_os = "solaris", target_os = "illumos")))]
 434     pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
 435         let mut nonblocking = nonblocking as libc::c_int;
 436         cvt(unsafe { libc::ioctl(self.as_raw_fd(), libc::FIONBIO, &mut nonblocking) }).map(drop)
 437     }
 438
 439     #[cfg(any(target_os = "solaris", target_os = "illumos"))]
 440     pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
 441         // FIONBIO is inadequate for sockets on illumos/Solaris, so use the
 442         // fcntl(F_[GS]ETFL)-based method provided by FileDesc instead.
 443         self.0.set_nonblocking(nonblocking)
 444     }
 445
 446     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
 447         let raw: c_int = getsockopt(self, libc::SOL_SOCKET, libc::SO_ERROR)?;
 448         if raw == 0 { Ok(None) } else { Ok(Some(io::Error::from_raw_os_error(raw as i32))) }
 449     }
 450
 451     // This is used by sys_common code to abstract over Windows and Unix.
 452     pub fn as_raw(&self) -> RawFd {
 453         self.as_raw_fd()
 454     }
 455 }
 456
 457 impl AsInner<FileDesc> for Socket {
 458     fn as_inner(&self) -> &FileDesc {
 459         &self.0
 460     }
 461 }
 462
 463 impl IntoInner<FileDesc> for Socket {
 464     fn into_inner(self) -> FileDesc {
 465         self.0
 466     }
 467 }
 468
 469 impl FromInner<FileDesc> for Socket {
 470     fn from_inner(file_desc: FileDesc) -> Self {
 471         Self(file_desc)
 472     }
 473 }
 474
 475 impl AsFd for Socket {
 476     fn as_fd(&self) -> BorrowedFd<'_> {
 477         self.0.as_fd()
 478     }
 479 }
 480
 481 impl AsRawFd for Socket {
 482     fn as_raw_fd(&self) -> RawFd {
 483         self.0.as_raw_fd()
 484     }
 485 }
 486
 487 impl IntoRawFd for Socket {
 488     fn into_raw_fd(self) -> RawFd {
 489         self.0.into_raw_fd()
 490     }
 491 }
 492
 493 impl FromRawFd for Socket {
 494     unsafe fn from_raw_fd(raw_fd: RawFd) -> Self {
 495         Self(FromRawFd::from_raw_fd(raw_fd))
 496     }
 497 }
 498
 499 // In versions of glibc prior to 2.26, there's a bug where the DNS resolver
 500 // will cache the contents of /etc/resolv.conf, so changes to that file on disk
 501 // can be ignored by a long-running program. That can break DNS lookups on e.g.
 502 // laptops where the network comes and goes. See
 503 // https://sourceware.org/bugzilla/show_bug.cgi?id=984. Note however that some
 504 // distros including Debian have patched glibc to fix this for a long time.
 505 //
 506 // A workaround for this bug is to call the res_init libc function, to clear
 507 // the cached configs. Unfortunately, while we believe glibc's implementation
 508 // of res_init is thread-safe, we know that other implementations are not
 509 // (https://github.com/rust-lang/rust/issues/43592). Code here in libstd could
 510 // try to synchronize its res_init calls with a Mutex, but that wouldn't
 511 // protect programs that call into libc in other ways. So instead of calling
 512 // res_init unconditionally, we call it only when we detect we're linking
 513 // against glibc version < 2.26. (That is, when we both know its needed and
 514 // believe it's thread-safe).
 515 #[cfg(all(target_os = "linux", target_env = "gnu"))]
 516 fn on_resolver_failure() {
 517     use crate::sys;
 518
 519     // If the version fails to parse, we treat it the same as "not glibc".
 520     if let Some(version) = sys::os::glibc_version() {
 521         if version < (2, 26) {
 522             unsafe { libc::res_init() };
 523         }
 524     }
 525 }
 526
 527 #[cfg(not(all(target_os = "linux", target_env = "gnu")))]
 528 fn on_resolver_failure() {}