1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
use crate::net::{TcpListener, TcpStream};

use std::fmt;
use std::io;
use std::net::SocketAddr;

#[cfg(unix)]
use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
#[cfg(windows)]
use std::os::windows::io::{AsRawSocket, FromRawSocket, IntoRawSocket, RawSocket};
use std::time::Duration;

cfg_net! {
    /// A TCP socket that has not yet been converted to a `TcpStream` or
    /// `TcpListener`.
    ///
    /// `TcpSocket` wraps an operating system socket and enables the caller to
    /// configure the socket before establishing a TCP connection or accepting
    /// inbound connections. The caller is able to set socket option and explicitly
    /// bind the socket with a socket address.
    ///
    /// The underlying socket is closed when the `TcpSocket` value is dropped.
    ///
    /// `TcpSocket` should only be used directly if the default configuration used
    /// by `TcpStream::connect` and `TcpListener::bind` does not meet the required
    /// use case.
    ///
    /// Calling `TcpStream::connect("127.0.0.1:8080")` is equivalent to:
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     let stream = socket.connect(addr).await?;
    /// # drop(stream);
    ///
    ///     Ok(())
    /// }
    /// ```
    ///
    /// Calling `TcpListener::bind("127.0.0.1:8080")` is equivalent to:
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     // On platforms with Berkeley-derived sockets, this allows to quickly
    ///     // rebind a socket, without needing to wait for the OS to clean up the
    ///     // previous one.
    ///     //
    ///     // On Windows, this allows rebinding sockets which are actively in use,
    ///     // which allows “socket hijacking”, so we explicitly don't set it here.
    ///     // https://docs.microsoft.com/en-us/windows/win32/winsock/using-so-reuseaddr-and-so-exclusiveaddruse
    ///     socket.set_reuseaddr(true)?;
    ///     socket.bind(addr)?;
    ///
    ///     let listener = socket.listen(1024)?;
    /// # drop(listener);
    ///
    ///     Ok(())
    /// }
    /// ```
    ///
    /// Setting socket options not explicitly provided by `TcpSocket` may be done by
    /// accessing the `RawFd`/`RawSocket` using [`AsRawFd`]/[`AsRawSocket`] and
    /// setting the option with a crate like [`socket2`].
    ///
    /// [`RawFd`]: https://doc.rust-lang.org/std/os/unix/io/type.RawFd.html
    /// [`RawSocket`]: https://doc.rust-lang.org/std/os/windows/io/type.RawSocket.html
    /// [`AsRawFd`]: https://doc.rust-lang.org/std/os/unix/io/trait.AsRawFd.html
    /// [`AsRawSocket`]: https://doc.rust-lang.org/std/os/windows/io/trait.AsRawSocket.html
    /// [`socket2`]: https://docs.rs/socket2/
    #[cfg_attr(docsrs, doc(alias = "connect_std"))]
    pub struct TcpSocket {
        inner: socket2::Socket,
    }
}

impl TcpSocket {
    /// Creates a new socket configured for IPv4.
    ///
    /// Calls `socket(2)` with `AF_INET` and `SOCK_STREAM`.
    ///
    /// # Returns
    ///
    /// On success, the newly created `TcpSocket` is returned. If an error is
    /// encountered, it is returned instead.
    ///
    /// # Examples
    ///
    /// Create a new IPv4 socket and start listening.
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///     let socket = TcpSocket::new_v4()?;
    ///     socket.bind(addr)?;
    ///
    ///     let listener = socket.listen(128)?;
    /// # drop(listener);
    ///     Ok(())
    /// }
    /// ```
    pub fn new_v4() -> io::Result<TcpSocket> {
        TcpSocket::new(socket2::Domain::IPV4)
    }

    /// Creates a new socket configured for IPv6.
    ///
    /// Calls `socket(2)` with `AF_INET6` and `SOCK_STREAM`.
    ///
    /// # Returns
    ///
    /// On success, the newly created `TcpSocket` is returned. If an error is
    /// encountered, it is returned instead.
    ///
    /// # Examples
    ///
    /// Create a new IPv6 socket and start listening.
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "[::1]:8080".parse().unwrap();
    ///     let socket = TcpSocket::new_v6()?;
    ///     socket.bind(addr)?;
    ///
    ///     let listener = socket.listen(128)?;
    /// # drop(listener);
    ///     Ok(())
    /// }
    /// ```
    pub fn new_v6() -> io::Result<TcpSocket> {
        TcpSocket::new(socket2::Domain::IPV6)
    }

    fn new(domain: socket2::Domain) -> io::Result<TcpSocket> {
        let ty = socket2::Type::STREAM;
        #[cfg(any(
            target_os = "android",
            target_os = "dragonfly",
            target_os = "freebsd",
            target_os = "fuchsia",
            target_os = "illumos",
            target_os = "linux",
            target_os = "netbsd",
            target_os = "openbsd"
        ))]
        let ty = ty.nonblocking();
        let inner = socket2::Socket::new(domain, ty, Some(socket2::Protocol::TCP))?;
        #[cfg(not(any(
            target_os = "android",
            target_os = "dragonfly",
            target_os = "freebsd",
            target_os = "fuchsia",
            target_os = "illumos",
            target_os = "linux",
            target_os = "netbsd",
            target_os = "openbsd"
        )))]
        inner.set_nonblocking(true)?;
        Ok(TcpSocket { inner })
    }

    /// Allows the socket to bind to an in-use address.
    ///
    /// Behavior is platform specific. Refer to the target platform's
    /// documentation for more details.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     socket.set_reuseaddr(true)?;
    ///     socket.bind(addr)?;
    ///
    ///     let listener = socket.listen(1024)?;
    /// # drop(listener);
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn set_reuseaddr(&self, reuseaddr: bool) -> io::Result<()> {
        self.inner.set_reuse_address(reuseaddr)
    }

    /// Retrieves the value set for `SO_REUSEADDR` on this socket.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     socket.set_reuseaddr(true)?;
    ///     assert!(socket.reuseaddr().unwrap());
    ///     socket.bind(addr)?;
    ///
    ///     let listener = socket.listen(1024)?;
    ///     Ok(())
    /// }
    /// ```
    pub fn reuseaddr(&self) -> io::Result<bool> {
        self.inner.reuse_address()
    }

    /// Allows the socket to bind to an in-use port. Only available for unix systems
    /// (excluding Solaris & Illumos).
    ///
    /// Behavior is platform specific. Refer to the target platform's
    /// documentation for more details.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     socket.set_reuseport(true)?;
    ///     socket.bind(addr)?;
    ///
    ///     let listener = socket.listen(1024)?;
    ///     Ok(())
    /// }
    /// ```
    #[cfg(all(unix, not(target_os = "solaris"), not(target_os = "illumos")))]
    #[cfg_attr(
        docsrs,
        doc(cfg(all(unix, not(target_os = "solaris"), not(target_os = "illumos"))))
    )]
    pub fn set_reuseport(&self, reuseport: bool) -> io::Result<()> {
        self.inner.set_reuse_port(reuseport)
    }

    /// Allows the socket to bind to an in-use port. Only available for unix systems
    /// (excluding Solaris & Illumos).
    ///
    /// Behavior is platform specific. Refer to the target platform's
    /// documentation for more details.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     socket.set_reuseport(true)?;
    ///     assert!(socket.reuseport().unwrap());
    ///     socket.bind(addr)?;
    ///
    ///     let listener = socket.listen(1024)?;
    ///     Ok(())
    /// }
    /// ```
    #[cfg(all(unix, not(target_os = "solaris"), not(target_os = "illumos")))]
    #[cfg_attr(
        docsrs,
        doc(cfg(all(unix, not(target_os = "solaris"), not(target_os = "illumos"))))
    )]
    pub fn reuseport(&self) -> io::Result<bool> {
        self.inner.reuse_port()
    }

    /// Sets the size of the TCP send buffer on this socket.
    ///
    /// On most operating systems, this sets the `SO_SNDBUF` socket option.
    pub fn set_send_buffer_size(&self, size: u32) -> io::Result<()> {
        self.inner.set_send_buffer_size(size as usize)
    }

    /// Returns the size of the TCP send buffer for this socket.
    ///
    /// On most operating systems, this is the value of the `SO_SNDBUF` socket
    /// option.
    ///
    /// Note that if [`set_send_buffer_size`] has been called on this socket
    /// previously, the value returned by this function may not be the same as
    /// the argument provided to `set_send_buffer_size`. This is for the
    /// following reasons:
    ///
    /// * Most operating systems have minimum and maximum allowed sizes for the
    ///   send buffer, and will clamp the provided value if it is below the
    ///   minimum or above the maximum. The minimum and maximum buffer sizes are
    ///   OS-dependent.
    /// * Linux will double the buffer size to account for internal bookkeeping
    ///   data, and returns the doubled value from `getsockopt(2)`. As per `man
    ///   7 socket`:
    ///   > Sets or gets the maximum socket send buffer in bytes. The
    ///   > kernel doubles this value (to allow space for bookkeeping
    ///   > overhead) when it is set using `setsockopt(2)`, and this doubled
    ///   > value is returned by `getsockopt(2)`.
    ///
    /// [`set_send_buffer_size`]: #method.set_send_buffer_size
    pub fn send_buffer_size(&self) -> io::Result<u32> {
        self.inner.send_buffer_size().map(|n| n as u32)
    }

    /// Sets the size of the TCP receive buffer on this socket.
    ///
    /// On most operating systems, this sets the `SO_RCVBUF` socket option.
    pub fn set_recv_buffer_size(&self, size: u32) -> io::Result<()> {
        self.inner.set_recv_buffer_size(size as usize)
    }

    /// Returns the size of the TCP receive buffer for this socket.
    ///
    /// On most operating systems, this is the value of the `SO_RCVBUF` socket
    /// option.
    ///
    /// Note that if [`set_recv_buffer_size`] has been called on this socket
    /// previously, the value returned by this function may not be the same as
    /// the argument provided to `set_send_buffer_size`. This is for the
    /// following reasons:
    ///
    /// * Most operating systems have minimum and maximum allowed sizes for the
    ///   receive buffer, and will clamp the provided value if it is below the
    ///   minimum or above the maximum. The minimum and maximum buffer sizes are
    ///   OS-dependent.
    /// * Linux will double the buffer size to account for internal bookkeeping
    ///   data, and returns the doubled value from `getsockopt(2)`. As per `man
    ///   7 socket`:
    ///   > Sets or gets the maximum socket send buffer in bytes. The
    ///   > kernel doubles this value (to allow space for bookkeeping
    ///   > overhead) when it is set using `setsockopt(2)`, and this doubled
    ///   > value is returned by `getsockopt(2)`.
    ///
    /// [`set_recv_buffer_size`]: #method.set_recv_buffer_size
    pub fn recv_buffer_size(&self) -> io::Result<u32> {
        self.inner.recv_buffer_size().map(|n| n as u32)
    }

    /// Sets the linger duration of this socket by setting the SO_LINGER option.
    ///
    /// This option controls the action taken when a stream has unsent messages and the stream is
    /// closed. If SO_LINGER is set, the system shall block the process until it can transmit the
    /// data or until the time expires.
    ///
    /// If SO_LINGER is not specified, and the socket is closed, the system handles the call in a
    /// way that allows the process to continue as quickly as possible.
    pub fn set_linger(&self, dur: Option<Duration>) -> io::Result<()> {
        self.inner.set_linger(dur)
    }

    /// Reads the linger duration for this socket by getting the `SO_LINGER`
    /// option.
    ///
    /// For more information about this option, see [`set_linger`].
    ///
    /// [`set_linger`]: TcpSocket::set_linger
    pub fn linger(&self) -> io::Result<Option<Duration>> {
        self.inner.linger()
    }

    /// Gets the value of the `IP_TOS` option for this socket.
    ///
    /// For more information about this option, see [`set_tos`].
    ///
    /// **NOTE:** On Windows, `IP_TOS` is only supported on [Windows 8+ or
    /// Windows Server 2012+.](https://docs.microsoft.com/en-us/windows/win32/winsock/ipproto-ip-socket-options)
    ///
    /// [`set_tos`]: Self::set_tos
    // https://docs.rs/socket2/0.4.2/src/socket2/socket.rs.html#1178
    #[cfg(not(any(
        target_os = "fuchsia",
        target_os = "redox",
        target_os = "solaris",
        target_os = "illumos",
    )))]
    #[cfg_attr(
        docsrs,
        doc(cfg(not(any(
            target_os = "fuchsia",
            target_os = "redox",
            target_os = "solaris",
            target_os = "illumos",
        ))))
    )]
    pub fn tos(&self) -> io::Result<u32> {
        self.inner.tos()
    }

    /// Sets the value for the `IP_TOS` option on this socket.
    ///
    /// This value sets the type-of-service field that is used in every packet
    /// sent from this socket.
    ///
    /// **NOTE:** On Windows, `IP_TOS` is only supported on [Windows 8+ or
    /// Windows Server 2012+.](https://docs.microsoft.com/en-us/windows/win32/winsock/ipproto-ip-socket-options)
    // https://docs.rs/socket2/0.4.2/src/socket2/socket.rs.html#1178
    #[cfg(not(any(
        target_os = "fuchsia",
        target_os = "redox",
        target_os = "solaris",
        target_os = "illumos",
    )))]
    #[cfg_attr(
        docsrs,
        doc(cfg(not(any(
            target_os = "fuchsia",
            target_os = "redox",
            target_os = "solaris",
            target_os = "illumos",
        ))))
    )]
    pub fn set_tos(&self, tos: u32) -> io::Result<()> {
        self.inner.set_tos(tos)
    }

    /// Gets the value for the `SO_BINDTODEVICE` option on this socket
    ///
    /// This value gets the socket binded device's interface name.
    #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux",))]
    #[cfg_attr(
        docsrs,
        doc(cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux",)))
    )]
    pub fn device(&self) -> io::Result<Option<Vec<u8>>> {
        self.inner.device()
    }

    /// Sets the value for the `SO_BINDTODEVICE` option on this socket
    ///
    /// If a socket is bound to an interface, only packets received from that
    /// particular interface are processed by the socket. Note that this only
    /// works for some socket types, particularly `AF_INET` sockets.
    ///
    /// If `interface` is `None` or an empty string it removes the binding.
    #[cfg(all(any(target_os = "android", target_os = "fuchsia", target_os = "linux")))]
    #[cfg_attr(
        docsrs,
        doc(cfg(all(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))))
    )]
    pub fn bind_device(&self, interface: Option<&[u8]>) -> io::Result<()> {
        self.inner.bind_device(interface)
    }

    /// Gets the local address of this socket.
    ///
    /// Will fail on windows if called before `bind`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     socket.bind(addr)?;
    ///     assert_eq!(socket.local_addr().unwrap().to_string(), "127.0.0.1:8080");
    ///     let listener = socket.listen(1024)?;
    ///     Ok(())
    /// }
    /// ```
    pub fn local_addr(&self) -> io::Result<SocketAddr> {
        self.inner.local_addr().and_then(convert_address)
    }

    /// Returns the value of the `SO_ERROR` option.
    pub fn take_error(&self) -> io::Result<Option<io::Error>> {
        self.inner.take_error()
    }

    /// Binds the socket to the given address.
    ///
    /// This calls the `bind(2)` operating-system function. Behavior is
    /// platform specific. Refer to the target platform's documentation for more
    /// details.
    ///
    /// # Examples
    ///
    /// Bind a socket before listening.
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     socket.bind(addr)?;
    ///
    ///     let listener = socket.listen(1024)?;
    /// # drop(listener);
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn bind(&self, addr: SocketAddr) -> io::Result<()> {
        self.inner.bind(&addr.into())
    }

    /// Establishes a TCP connection with a peer at the specified socket address.
    ///
    /// The `TcpSocket` is consumed. Once the connection is established, a
    /// connected [`TcpStream`] is returned. If the connection fails, the
    /// encountered error is returned.
    ///
    /// [`TcpStream`]: TcpStream
    ///
    /// This calls the `connect(2)` operating-system function. Behavior is
    /// platform specific. Refer to the target platform's documentation for more
    /// details.
    ///
    /// # Examples
    ///
    /// Connecting to a peer.
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     let stream = socket.connect(addr).await?;
    /// # drop(stream);
    ///
    ///     Ok(())
    /// }
    /// ```
    pub async fn connect(self, addr: SocketAddr) -> io::Result<TcpStream> {
        if let Err(err) = self.inner.connect(&addr.into()) {
            #[cfg(unix)]
            if err.raw_os_error() != Some(libc::EINPROGRESS) {
                return Err(err);
            }
            #[cfg(windows)]
            if err.kind() != io::ErrorKind::WouldBlock {
                return Err(err);
            }
        }
        #[cfg(unix)]
        let mio = {
            use std::os::unix::io::{FromRawFd, IntoRawFd};

            let raw_fd = self.inner.into_raw_fd();
            unsafe { mio::net::TcpStream::from_raw_fd(raw_fd) }
        };

        #[cfg(windows)]
        let mio = {
            use std::os::windows::io::{FromRawSocket, IntoRawSocket};

            let raw_socket = self.inner.into_raw_socket();
            unsafe { mio::net::TcpStream::from_raw_socket(raw_socket) }
        };

        TcpStream::connect_mio(mio).await
    }

    /// Converts the socket into a `TcpListener`.
    ///
    /// `backlog` defines the maximum number of pending connections are queued
    /// by the operating system at any given time. Connection are removed from
    /// the queue with [`TcpListener::accept`]. When the queue is full, the
    /// operating-system will start rejecting connections.
    ///
    /// [`TcpListener::accept`]: TcpListener::accept
    ///
    /// This calls the `listen(2)` operating-system function, marking the socket
    /// as a passive socket. Behavior is platform specific. Refer to the target
    /// platform's documentation for more details.
    ///
    /// # Examples
    ///
    /// Create a `TcpListener`.
    ///
    /// ```no_run
    /// use tokio::net::TcpSocket;
    ///
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let addr = "127.0.0.1:8080".parse().unwrap();
    ///
    ///     let socket = TcpSocket::new_v4()?;
    ///     socket.bind(addr)?;
    ///
    ///     let listener = socket.listen(1024)?;
    /// # drop(listener);
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn listen(self, backlog: u32) -> io::Result<TcpListener> {
        self.inner.listen(backlog as i32)?;
        #[cfg(unix)]
        let mio = {
            use std::os::unix::io::{FromRawFd, IntoRawFd};

            let raw_fd = self.inner.into_raw_fd();
            unsafe { mio::net::TcpListener::from_raw_fd(raw_fd) }
        };

        #[cfg(windows)]
        let mio = {
            use std::os::windows::io::{FromRawSocket, IntoRawSocket};

            let raw_socket = self.inner.into_raw_socket();
            unsafe { mio::net::TcpListener::from_raw_socket(raw_socket) }
        };

        TcpListener::new(mio)
    }

    /// Converts a [`std::net::TcpStream`] into a `TcpSocket`. The provided
    /// socket must not have been connected prior to calling this function. This
    /// function is typically used together with crates such as [`socket2`] to
    /// configure socket options that are not available on `TcpSocket`.
    ///
    /// [`std::net::TcpStream`]: struct@std::net::TcpStream
    /// [`socket2`]: https://docs.rs/socket2/
    ///
    /// # Examples
    ///
    /// ```
    /// use tokio::net::TcpSocket;
    /// use socket2::{Domain, Socket, Type};
    ///
    /// #[tokio::main]
    /// async fn main() -> std::io::Result<()> {
    ///
    ///     let socket2_socket = Socket::new(Domain::IPV4, Type::STREAM, None)?;
    ///
    ///     let socket = TcpSocket::from_std_stream(socket2_socket.into());
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn from_std_stream(std_stream: std::net::TcpStream) -> TcpSocket {
        #[cfg(unix)]
        {
            use std::os::unix::io::{FromRawFd, IntoRawFd};

            let raw_fd = std_stream.into_raw_fd();
            unsafe { TcpSocket::from_raw_fd(raw_fd) }
        }

        #[cfg(windows)]
        {
            use std::os::windows::io::{FromRawSocket, IntoRawSocket};

            let raw_socket = std_stream.into_raw_socket();
            unsafe { TcpSocket::from_raw_socket(raw_socket) }
        }
    }
}

fn convert_address(address: socket2::SockAddr) -> io::Result<SocketAddr> {
    match address.as_socket() {
        Some(address) => Ok(address),
        None => Err(io::Error::new(
            io::ErrorKind::InvalidInput,
            "invalid address family (not IPv4 or IPv6)",
        )),
    }
}

impl fmt::Debug for TcpSocket {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.inner.fmt(fmt)
    }
}

#[cfg(unix)]
impl AsRawFd for TcpSocket {
    fn as_raw_fd(&self) -> RawFd {
        self.inner.as_raw_fd()
    }
}

#[cfg(unix)]
impl FromRawFd for TcpSocket {
    /// Converts a `RawFd` to a `TcpSocket`.
    ///
    /// # Notes
    ///
    /// The caller is responsible for ensuring that the socket is in
    /// non-blocking mode.
    unsafe fn from_raw_fd(fd: RawFd) -> TcpSocket {
        let inner = socket2::Socket::from_raw_fd(fd);
        TcpSocket { inner }
    }
}

#[cfg(unix)]
impl IntoRawFd for TcpSocket {
    fn into_raw_fd(self) -> RawFd {
        self.inner.into_raw_fd()
    }
}

#[cfg(windows)]
impl IntoRawSocket for TcpSocket {
    fn into_raw_socket(self) -> RawSocket {
        self.inner.into_raw_socket()
    }
}

#[cfg(windows)]
impl AsRawSocket for TcpSocket {
    fn as_raw_socket(&self) -> RawSocket {
        self.inner.as_raw_socket()
    }
}

#[cfg(windows)]
impl FromRawSocket for TcpSocket {
    /// Converts a `RawSocket` to a `TcpStream`.
    ///
    /// # Notes
    ///
    /// The caller is responsible for ensuring that the socket is in
    /// non-blocking mode.
    unsafe fn from_raw_socket(socket: RawSocket) -> TcpSocket {
        let inner = socket2::Socket::from_raw_socket(socket);
        TcpSocket { inner }
    }
}