Add support for SO_TIMESTAMP

CHANGELOG.md

@@ -6,6 +6,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased]
 
 ### Added
+- Added `nix::sys::socket::ControlMessage::ScmTimestamp`
+  ([#663](https://github.com/nix-rust/nix/pull/663))
 - Added `sys::signal::SigAction::{ flags, mask, handler}`
   ([#611](https://github.com/nix-rust/nix/pull/609)
 - Added `nix::sys::pthread::pthread_self`

src/sys/socket/consts.rs

@@ -109,6 +109,7 @@ mod os {
 
     // Ancillary message types
     pub const SCM_RIGHTS: c_int = libc::SCM_RIGHTS;
+    pub const SCM_TIMESTAMP: c_int = libc::SCM_TIMESTAMP;
 }
 
 // Not all of these constants exist on freebsd
@@ -235,6 +236,7 @@ mod os {
 
     // Ancillary message types
     pub const SCM_RIGHTS: c_int = 1;
+    pub const SCM_TIMESTAMP: c_int = libc::SCM_TIMESTAMP;
 }
 
 #[cfg(target_os = "dragonfly")]

src/sys/socket/mod.rs

@@ -9,6 +9,7 @@ use libc::{c_void, c_int, socklen_t, size_t, pid_t, uid_t, gid_t};
 use std::{mem, ptr, slice};
 use std::os::unix::io::RawFd;
 use sys::uio::IoVec;
+use sys::time::TimeVal;
 
 mod addr;
 mod consts;
@@ -162,6 +163,10 @@ impl<'a> Iterator for CmsgIterator<'a> {
                     slice::from_raw_parts(
                         &cmsg.cmsg_data as *const _ as *const _, 1)))
             },
+            (SOL_SOCKET, SCM_TIMESTAMP) => unsafe {
+                Some(ControlMessage::ScmTimestamp(
+                    &*(&cmsg.cmsg_data as *const _ as *const _)))
+            },
             (_, _) => unsafe {
                 Some(ControlMessage::Unknown(UnknownCmsg(
                     &cmsg,
@@ -182,6 +187,11 @@ pub enum ControlMessage<'a> {
     /// "Ancillary messages" section of the
     /// [unix(7) man page](http://man7.org/linux/man-pages/man7/unix.7.html).
     ScmRights(&'a [RawFd]),
+    /// A message of type SCM_TIMESTAMP, containing the time the packet
+    /// was received by the kernel. See the kernel's explanation in
+    /// "SO_TIMESTAMP" of
+    /// [networking/timestamping](https://www.kernel.org/doc/Documentation/networking/timestamping.txt).
+    ScmTimestamp(&'a TimeVal),
     #[doc(hidden)]
     Unknown(UnknownCmsg<'a>),
 }
@@ -207,6 +217,9 @@ impl<'a> ControlMessage<'a> {
             ControlMessage::ScmRights(fds) => {
                 mem::size_of_val(fds)
             },
+            ControlMessage::ScmTimestamp(t) => {
+                mem::size_of_val(t)
+            },
             ControlMessage::Unknown(UnknownCmsg(_, bytes)) => {
                 mem::size_of_val(bytes)
             }
@@ -237,6 +250,25 @@ impl<'a> ControlMessage<'a> {
 
                 copy_bytes(fds, buf);
             },
+            ControlMessage::ScmTimestamp(t) => {
+                let cmsg = cmsghdr {
+                    cmsg_len: self.len() as type_of_cmsg_len,
+                    cmsg_level: SOL_SOCKET,
+                    cmsg_type: SCM_TIMESTAMP,
+                    cmsg_data: [],
+                };
+                copy_bytes(&cmsg, buf);
+
+                let padlen = cmsg_align(mem::size_of_val(&cmsg)) -
+                    mem::size_of_val(&cmsg);
+
+                let mut tmpbuf = &mut [][..];
+                mem::swap(&mut tmpbuf, buf);
+                let (_padding, mut remainder) = tmpbuf.split_at_mut(padlen);
+                mem::swap(buf, &mut remainder);
+
+                copy_bytes(t, buf);
+            },
             ControlMessage::Unknown(UnknownCmsg(orig_cmsg, bytes)) => {
                 copy_bytes(orig_cmsg, buf);
                 copy_bytes(bytes, buf);

src/sys/socket/sockopt.rs

@@ -176,6 +176,7 @@ sockopt_impl!(GetOnly, SockType, consts::SOL_SOCKET, consts::SO_TYPE, super::Soc
 sockopt_impl!(GetOnly, AcceptConn, consts::SOL_SOCKET, consts::SO_ACCEPTCONN, bool);
 #[cfg(target_os = "linux")]
 sockopt_impl!(GetOnly, OriginalDst, consts::SOL_IP, consts::SO_ORIGINAL_DST, sockaddr_in);
+sockopt_impl!(Both, ReceiveTimestamp, consts::SOL_SOCKET, consts::SO_TIMESTAMP, bool);
 
 /*
  *