Merge pull request #834 from hunhoffe/bug/peek_slice

Match the behavior of peek_slice to recv_slice

src/socket/tcp.rs

@@ -1173,10 +1173,7 @@ impl<'a> Socket<'a> {
  ///
  /// This function otherwise behaves identically to [recv_slice](#method.recv_slice).
  pub fn peek_slice(&mut self, data: &mut [u8]) -> Result<usize, RecvError> {
- let buffer = self.peek(data.len())?;
- let data = &mut data[..buffer.len()];
- data.copy_from_slice(buffer);
- Ok(buffer.len())
+ Ok(self.rx_buffer.read_allocated(0, data))
  }
 
  /// Return the amount of octets queued in the transmit buffer.
@@ -1868,7 +1865,10 @@ impl<'a> Socket<'a> {
  let assembler_was_empty = self.assembler.is_empty();
 
  // Try adding payload octets to the assembler.
- let Ok(contig_len) = self.assembler.add_then_remove_front(payload_offset, payload_len) else {
+ let Ok(contig_len) = self
+ .assembler
+ .add_then_remove_front(payload_offset, payload_len)
+ else {
  net_debug!(
  "assembler: too many holes to add {} octets at offset {}",
  payload_len,
@@ -3667,6 +3667,58 @@ mod test {
  assert_eq!(s.rx_buffer.dequeue_many(6), &b"abcdef"[..]);
  }
 
+ #[test]
+ fn test_peek_slice() {
+ const BUF_SIZE: usize = 10;
+
+ let send_buf = b"0123456";
+
+ let mut s = socket_established_with_buffer_sizes(BUF_SIZE, BUF_SIZE);
+
+ // Populate the recv buffer
+ send!(
+ s,
+ TcpRepr {
+ seq_number: REMOTE_SEQ + 1,
+ ack_number: Some(LOCAL_SEQ + 1),
+ payload: &send_buf[..],
+ ..SEND_TEMPL
+ }
+ );
+
+ // Peek into the recv buffer
+ let mut peeked_buf = [0u8; BUF_SIZE];
+ let actually_peeked = s.peek_slice(&mut peeked_buf[..]).unwrap();
+ let mut recv_buf = [0u8; BUF_SIZE];
+ let actually_recvd = s.recv_slice(&mut recv_buf[..]).unwrap();
+ assert_eq!(
+ &mut peeked_buf[..actually_peeked],
+ &mut recv_buf[..actually_recvd]
+ );
+ }
+
+ #[test]
+ fn test_peek_slice_buffer_wrap() {
+ const BUF_SIZE: usize = 10;
+
+ let send_buf = b"0123456789";
+
+ let mut s = socket_established_with_buffer_sizes(BUF_SIZE, BUF_SIZE);
+
+ let _ = s.rx_buffer.enqueue_slice(&send_buf[..8]);
+ let _ = s.rx_buffer.dequeue_many(6);
+ let _ = s.rx_buffer.enqueue_slice(&send_buf[..5]);
+
+ let mut peeked_buf = [0u8; BUF_SIZE];
+ let actually_peeked = s.peek_slice(&mut peeked_buf[..]).unwrap();
+ let mut recv_buf = [0u8; BUF_SIZE];
+ let actually_recvd = s.recv_slice(&mut recv_buf[..]).unwrap();
+ assert_eq!(
+ &mut peeked_buf[..actually_peeked],
+ &mut recv_buf[..actually_recvd]
+ );
+ }
+
  fn setup_rfc2018_cases() -> (TestSocket, Vec<u8>) {
  // This is a utility function used by the tests for RFC 2018 cases. It configures a socket
  // in a particular way suitable for those cases.