Move MsgFlags onto RecvMsgSettings

apps/src/recvfrom.rs

@@ -2,8 +2,6 @@ use dgram::RecvData;
 
 use std::io;
 
-// TODO: migrate setup code to use [dgram::SocketCapabilities].
-
 /// For Linux, try to detect if GRO is available. If it is, the
 /// [`UdpGroSegment`] socket option will be set on the passed socket.
 ///
@@ -41,26 +39,21 @@ pub fn recv_from(
     use dgram::RecvMsgSettings;
     use std::os::unix::io::AsRawFd;
 
-    let mut recvmsg_cmsg_settings = RecvMsgSettings {
-        store_cmsgs: false,
-        cmsg_space: vec![],
-    };
-
+    let mut recvmsg_cmsg_settings = RecvMsgSettings::default();
     socket.try_io(|| {
         let fd =
             unsafe { std::os::fd::BorrowedFd::borrow_raw(socket.as_raw_fd()) };
 
-        dgram::sync::recv_from(&fd, buf, None, &mut recvmsg_cmsg_settings)
+        dgram::sync::recv_from(&fd, buf, &mut recvmsg_cmsg_settings)
     })
 }
 
-// TODO: shoould it be up to the user to handle blocking errors?
 #[cfg(not(target_os = "linux"))]
 fn recv_from(
     socket: &mio::net::UdpSocket, buf: &mut [u8],
 ) -> std::io::Result<RecvData> {
     match socket.recv_from(buf) {
         Ok((read, from)) => Ok(RecvData::new(Some(from), read, 0)),
-        Err(_) => {},
+        Err(e) => Err(e),
     }
 }

dgram/src/lib.rs

@@ -13,6 +13,7 @@ use libc::in_pktinfo;
 use libc::sockaddr_in;
 use libc::sockaddr_in6;
 use nix::sys::socket::ControlMessageOwned;
+use nix::sys::socket::MsgFlags;
 
 /// Settings for handling control messages when sending data.
 #[cfg(target_os = "linux")]
@@ -30,10 +31,10 @@ pub struct SendMsgSettings {
 
 /// Settings for handling control messages when receiving data.
 #[cfg(target_os = "linux")]
-#[derive(Clone, Default)]
+#[derive(Clone)]
 pub struct RecvMsgSettings {
-    // TODO: deprecate store_cmsgs and only store based on what cmsg_space can
-    // handle.
+    // TODO(evanrittenhouse): deprecate store_cmsgs and only store based on what
+    // cmsg_space can handle.
     /// If cmsgs should be stored when receiving a message. If set, cmsgs will
     /// be stored in the `cmsg_space` vector.
     pub store_cmsgs: bool,
@@ -45,6 +46,20 @@ pub struct RecvMsgSettings {
     ///
     /// [`cmsg_space`]: https://docs.rs/nix/latest/nix/macro.cmsg_space.html
     pub cmsg_space: Vec<u8>,
+    /// Flags for [`recvmsg`]. See [MsgFlags] for more.
+    ///
+    /// [`recvmsg`]: [nix::sys::socket::recvmsg]
+    pub msg_flags: MsgFlags,
+}
+
+impl Default for RecvMsgSettings {
+    fn default() -> Self {
+        Self {
+            msg_flags: MsgFlags::empty(),
+            store_cmsgs: false,
+            cmsg_space: vec![],
+        }
+    }
 }
 
 /// Output of a `recvmsg` call.

dgram/src/sync.rs

@@ -25,15 +25,9 @@ pub fn send_to(
 
 #[cfg(target_os = "linux")]
 pub fn recv_from(
-    fd: &impl AsFd, read_buf: &mut [u8], msg_flags: Option<MsgFlags>,
-    store_cmsg_settings: &mut RecvMsgSettings,
+    fd: &impl AsFd, read_buf: &mut [u8], recvmsg_settings: &mut RecvMsgSettings,
 ) -> Result<RecvData> {
-    let recvd = recv_msg(
-        fd,
-        read_buf,
-        msg_flags.unwrap_or(MsgFlags::empty()),
-        store_cmsg_settings,
-    );
+    let recvd = recv_msg(fd, read_buf, recvmsg_settings);
 
     match recvd {
         Ok(r) => Ok(r),

dgram/src/syscalls.rs

@@ -95,14 +95,14 @@ pub fn send_msg(
 /// to set any relevant socket options.
 #[cfg(target_os = "linux")]
 pub fn recv_msg(
-    fd: impl AsFd, read_buf: &mut [u8], msg_flags: MsgFlags,
-    recvmsg_settings: &mut RecvMsgSettings,
+    fd: impl AsFd, read_buf: &mut [u8], recvmsg_settings: &mut RecvMsgSettings,
 ) -> SyscallResult<RecvData> {
     use crate::IpOrigDstAddr;
 
     let RecvMsgSettings {
         store_cmsgs,
         ref mut cmsg_space,
+        msg_flags,
     } = recvmsg_settings;
 
     cmsg_space.clear();
@@ -115,7 +115,7 @@ pub fn recv_msg(
         borrowed.as_raw_fd(),
         iov_s,
         Some(cmsg_space),
-        msg_flags,
+        *msg_flags,
     ) {
         Ok(r) => {
             let bytes = r.bytes;
@@ -260,12 +260,8 @@ mod tests {
         sendmsg(send.as_raw_fd(), &iov, &[], MsgFlags::empty(), Some(&addr))?;
 
         let mut read_buf = [0; 4];
-        let recv_data = recv_msg(
-            recv,
-            &mut read_buf,
-            MsgFlags::empty(),
-            &mut RecvMsgSettings::default(),
-        )?;
+        let recv_data =
+            recv_msg(recv, &mut read_buf, &mut RecvMsgSettings::default())?;
 
         assert_eq!(recv_data.bytes, 4);
         assert_eq!(&read_buf, b"jets");
@@ -325,15 +321,11 @@ mod tests {
         let mut recvmsg_settings = RecvMsgSettings {
             store_cmsgs: true,
             cmsg_space,
+            msg_flags: MsgFlags::empty(),
         };
 
         let mut read_buf = [0; 4];
-        let recv_data = recv_msg(
-            recv,
-            &mut read_buf,
-            MsgFlags::empty(),
-            &mut recvmsg_settings,
-        )?;
+        let recv_data = recv_msg(recv, &mut read_buf, &mut recvmsg_settings)?;
 
         assert_eq!(recv_data.bytes, 4);
         assert_eq!(&read_buf, b"jets");