diff --git a/compio-driver/src/iocp/op.rs b/compio-driver/src/iocp/op.rs
index 705971b8..cf2b2740 100644
--- a/compio-driver/src/iocp/op.rs
+++ b/compio-driver/src/iocp/op.rs
@@ -786,6 +786,7 @@ pub struct RecvMsg<T: IoVectoredBufMut, C: IoBufMut, S> {
     fd: SharedFd<S>,
     buffer: T,
     control: C,
+    control_len: u32,
     _p: PhantomPinned,
 }
 
@@ -806,16 +807,22 @@ impl<T: IoVectoredBufMut, C: IoBufMut, S> RecvMsg<T, C, S> {
             fd,
             buffer,
             control,
+            control_len: 0,
             _p: PhantomPinned,
         }
     }
 }
 
 impl<T: IoVectoredBufMut, C: IoBufMut, S> IntoInner for RecvMsg<T, C, S> {
-    type Inner = ((T, C), SOCKADDR_STORAGE, socklen_t);
+    type Inner = ((T, C), SOCKADDR_STORAGE, socklen_t, usize);
 
     fn into_inner(self) -> Self::Inner {
-        ((self.buffer, self.control), self.addr, self.addr_len)
+        (
+            (self.buffer, self.control),
+            self.addr,
+            self.addr_len,
+            self.control_len as _,
+        )
     }
 }
 
@@ -837,6 +844,7 @@ impl<T: IoVectoredBufMut, C: IoBufMut, S: AsRawFd> OpCode for RecvMsg<T, C, S> {
             Control: std::mem::transmute::<IoSliceMut, WSABUF>(this.control.as_io_slice_mut()),
             dwFlags: 0,
         };
+        this.control_len = 0;
 
         let mut received = 0;
         let res = recvmsg_fn(
@@ -846,6 +854,7 @@ impl<T: IoVectoredBufMut, C: IoBufMut, S: AsRawFd> OpCode for RecvMsg<T, C, S> {
             optr,
             None,
         );
+        this.control_len = msg.Control.len;
         winsock_result(res, received)
     }
 
diff --git a/compio-driver/src/op.rs b/compio-driver/src/op.rs
index 89b60d10..743a6c5f 100644
--- a/compio-driver/src/op.rs
+++ b/compio-driver/src/op.rs
@@ -49,23 +49,47 @@ impl<T: SetBufInit, O> BufResultExt for BufResult<(usize, O), T> {
     }
 }
 
-/// Helper trait for [`RecvFrom`] and [`RecvFromVectored`].
+impl<T: SetBufInit, C: SetBufInit, O> BufResultExt for BufResult<(usize, usize, O), (T, C)> {
+    fn map_advanced(self) -> Self {
+        self.map(
+            |(init_buffer, init_control, obj), (mut buffer, mut control)| {
+                unsafe {
+                    buffer.set_buf_init(init_buffer);
+                    control.set_buf_init(init_control);
+                }
+                ((init_buffer, init_control, obj), (buffer, control))
+            },
+        )
+    }
+}
+
+/// Helper trait for [`RecvFrom`], [`RecvFromVectored`] and [`RecvMsg`].
 pub trait RecvResultExt {
     /// The mapped result.
-    type RecvFromResult;
+    type RecvResult;
 
     /// Create [`SockAddr`] if the result is [`Ok`].
-    fn map_addr(self) -> Self::RecvFromResult;
+    fn map_addr(self) -> Self::RecvResult;
 }
 
 impl<T> RecvResultExt for BufResult<usize, (T, sockaddr_storage, socklen_t)> {
-    type RecvFromResult = BufResult<(usize, SockAddr), T>;
+    type RecvResult = BufResult<(usize, SockAddr), T>;
+
+    fn map_addr(self) -> Self::RecvResult {
+        self.map_buffer(|(buffer, addr_buffer, addr_size)| (buffer, addr_buffer, addr_size, 0))
+            .map_addr()
+            .map_res(|(res, _, addr)| (res, addr))
+    }
+}
+
+impl<T> RecvResultExt for BufResult<usize, (T, sockaddr_storage, socklen_t, usize)> {
+    type RecvResult = BufResult<(usize, usize, SockAddr), T>;
 
-    fn map_addr(self) -> Self::RecvFromResult {
+    fn map_addr(self) -> Self::RecvResult {
         self.map2(
-            |res, (buffer, addr_buffer, addr_size)| {
+            |res, (buffer, addr_buffer, addr_size, len)| {
                 let addr = unsafe { SockAddr::new(addr_buffer, addr_size) };
-                ((res, addr), buffer)
+                ((res, len, addr), buffer)
             },
             |(buffer, ..)| buffer,
         )
diff --git a/compio-driver/src/unix/op.rs b/compio-driver/src/unix/op.rs
index aff5899a..2d14bc1b 100644
--- a/compio-driver/src/unix/op.rs
+++ b/compio-driver/src/unix/op.rs
@@ -411,15 +411,20 @@ impl<T: IoVectoredBufMut, C: IoBufMut, S> RecvMsg<T, C, S> {
         self.msg.msg_iov = self.slices.as_mut_ptr() as _;
         self.msg.msg_iovlen = self.slices.len() as _;
         self.msg.msg_control = self.control.as_buf_mut_ptr() as _;
-        self.msg.msg_controllen = self.control.buf_len() as _;
+        self.msg.msg_controllen = self.control.buf_capacity() as _;
     }
 }
 
 impl<T: IoVectoredBufMut, C: IoBufMut, S> IntoInner for RecvMsg<T, C, S> {
-    type Inner = ((T, C), sockaddr_storage, socklen_t);
+    type Inner = ((T, C), sockaddr_storage, socklen_t, usize);
 
     fn into_inner(self) -> Self::Inner {
-        ((self.buffer, self.control), self.addr, self.msg.msg_namelen)
+        (
+            (self.buffer, self.control),
+            self.addr,
+            self.msg.msg_namelen,
+            self.msg.msg_controllen as _,
+        )
     }
 }
 
diff --git a/compio-net/src/socket.rs b/compio-net/src/socket.rs
index 0f84dd08..d7bc5a8d 100644
--- a/compio-net/src/socket.rs
+++ b/compio-net/src/socket.rs
@@ -261,7 +261,7 @@ impl Socket {
         &self,
         buffer: T,
         control: C,
-    ) -> BufResult<(usize, SockAddr), (T, C)> {
+    ) -> BufResult<(usize, usize, SockAddr), (T, C)> {
         self.recv_msg_vectored([buffer], control)
             .await
             .map_buffer(|([buffer], control)| (buffer, control))
@@ -271,20 +271,14 @@ impl Socket {
         &self,
         buffer: T,
         control: C,
-    ) -> BufResult<(usize, SockAddr), (T, C)> {
+    ) -> BufResult<(usize, usize, SockAddr), (T, C)> {
         let fd = self.to_shared_fd();
         let op = RecvMsg::new(fd, buffer, control);
         compio_runtime::submit(op)
             .await
             .into_inner()
             .map_addr()
-            .map(|(init, obj), (mut buffer, control)| {
-                // SAFETY: The number of bytes received would not bypass the buffer capacity.
-                unsafe {
-                    buffer.set_buf_init(init);
-                }
-                ((init, obj), (buffer, control))
-            })
+            .map_advanced()
     }
 
     pub async fn send_to<T: IoBuf>(&self, buffer: T, addr: &SockAddr) -> BufResult<usize, T> {
diff --git a/compio-net/src/udp.rs b/compio-net/src/udp.rs
index 1063eed9..13e59d73 100644
--- a/compio-net/src/udp.rs
+++ b/compio-net/src/udp.rs
@@ -228,11 +228,11 @@ impl UdpSocket {
         &self,
         buffer: T,
         control: C,
-    ) -> BufResult<(usize, SocketAddr), (T, C)> {
+    ) -> BufResult<(usize, usize, SocketAddr), (T, C)> {
         self.inner
             .recv_msg(buffer, control)
             .await
-            .map_res(|(n, addr)| (n, addr.as_socket().expect("should be SocketAddr")))
+            .map_res(|(n, m, addr)| (n, m, addr.as_socket().expect("should be SocketAddr")))
     }
 
     /// Receives a single datagram message and ancillary data on the socket. On
@@ -241,11 +241,11 @@ impl UdpSocket {
         &self,
         buffer: T,
         control: C,
-    ) -> BufResult<(usize, SocketAddr), (T, C)> {
+    ) -> BufResult<(usize, usize, SocketAddr), (T, C)> {
         self.inner
             .recv_msg_vectored(buffer, control)
             .await
-            .map_res(|(n, addr)| (n, addr.as_socket().expect("should be SocketAddr")))
+            .map_res(|(n, m, addr)| (n, m, addr.as_socket().expect("should be SocketAddr")))
     }
 
     /// Sends data on the socket to the given address. On success, returns the
diff --git a/compio-net/tests/udp.rs b/compio-net/tests/udp.rs
index fe7dc263..d813290e 100644
--- a/compio-net/tests/udp.rs
+++ b/compio-net/tests/udp.rs
@@ -103,14 +103,18 @@ async fn send_msg_with_ipv6_ecn() {
 
     active.send_msg(MSG, control, passive_addr).await.unwrap();
 
-    let res = passive.recv_msg(Vec::with_capacity(20), [0u8; 32]).await;
-    assert_eq!(res.0.unwrap().1, active_addr);
-    assert_eq!(res.1.0, MSG.as_bytes());
+    let ((_, _, addr), (buffer, control)) = passive
+        .recv_msg(Vec::with_capacity(20), Vec::with_capacity(32))
+        .await
+        .unwrap();
+    assert_eq!(addr, active_addr);
+    assert_eq!(buffer, MSG.as_bytes());
     unsafe {
-        let mut iter = CMsgIter::new(&res.1.1);
+        let mut iter = CMsgIter::new(&control);
         let cmsg = iter.next().unwrap();
         assert_eq!(cmsg.level(), IPPROTO_IPV6);
         assert_eq!(cmsg.ty(), IPV6_TCLASS);
         assert_eq!(cmsg.data::<i32>(), &ECN_BITS);
+        assert!(iter.next().is_none());
     }
 }