rama-tls 0.4.0

rama TLS-agnostic types and utilities
Documentation 
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

use std::{num::NonZeroUsize, time::Duration};

use rama_core::{
    Service,
    error::{BoxError, ErrorContext},
    io::{
        HeapReader, PeekIoProvider, PrefixedIo,
        peek::{
            PeekOutput, PeekStopReason, PeekTimeoutError, PeekTimeoutPolicy, PeekVerdict,
            peek_input_until_verdict_growing_with_output, peek_input_until_verdict_with_options,
        },
    },
    service::RejectService,
    telemetry::tracing,
};
use rama_utils::octets::kib;
use tokio::time::Instant;

use crate::client::{ClientHello, ClientHelloHandshakePrefix, parse_client_hello_handshake_prefix};

use super::NoTlsRejectError;

/// A peek [`Service`] which returns the [`ClientHello`] to the inner
/// service for tls-detected traffic, and otherwise make use of the Reject service.
///
/// The difference with [`SniRouter`] is that the entire
/// [`ClientHello`] is parsed and returned instead of just the SNI. Use the router
/// in case all you care about is the SNI, given it is more efficient.
///
/// By default non-tls traffic is rejected using [`RejectService`].
/// Use [`PeekTlsClientHelloService::with_fallback`] to configure the fallback service.
/// A definitive non-TLS or malformed ClientHello prefix invokes that fallback
/// under either timeout policy; an inconclusive timeout is fail-open by default
/// and can be made fail-closed with
/// [`PeekTlsClientHelloService::with_peek_timeout_policy`].
///
/// Use the standalone [`peek_client_hello_from_input`] function if you prefer
/// this is as a standalone function instead.
///
/// [`SniRouter`]: super::SniRouter
#[derive(Debug, Clone)]
pub struct PeekTlsClientHelloService<S, F = RejectService<(), NoTlsRejectError>> {
    service: S,
    fallback: F,
    peek_timeout: Option<Duration>,
    peek_timeout_policy: PeekTimeoutPolicy,
}

impl<S> PeekTlsClientHelloService<S> {
    /// Create a new [`PeekTlsClientHelloService`].
    pub fn new(service: S) -> Self {
        Self {
            service,
            fallback: RejectService::new(NoTlsRejectError),
            peek_timeout: None,
            peek_timeout_policy: PeekTimeoutPolicy::default(),
        }
    }

    /// Attach a fallback [`Service`] to this [`PeekTlsClientHelloService`].
    ///
    /// Used in case the traffic is not Tls traffic (defined by the first bytes).
    pub fn with_fallback<F>(self, fallback: F) -> PeekTlsClientHelloService<S, F> {
        PeekTlsClientHelloService {
            service: self.service,
            fallback,
            peek_timeout: self.peek_timeout,
            peek_timeout_policy: self.peek_timeout_policy,
        }
    }
}

impl<S, F> PeekTlsClientHelloService<S, F> {
    rama_utils::macros::generate_set_and_with! {
        /// Set the maximum time spent peeking for a TLS ClientHello.
        ///
        /// A timeout is inconclusive. Use
        /// [`PeekTlsClientHelloService::with_peek_timeout_policy`] to choose
        /// whether it invokes the fallback or rejects the connection.
        pub fn peek_timeout(mut self, peek_timeout: Option<Duration>) -> Self {
            self.peek_timeout = peek_timeout;
            self
        }
    }

    rama_utils::macros::generate_set_and_with! {
        /// Set how an inconclusive peek timeout is handled.
        ///
        /// Defaults to [`PeekTimeoutPolicy::FailOpen`]. A definitive non-TLS or
        /// malformed ClientHello prefix invokes the fallback under either policy.
        pub fn peek_timeout_policy(mut self, peek_timeout_policy: PeekTimeoutPolicy) -> Self {
            self.peek_timeout_policy = peek_timeout_policy;
            self
        }
    }
}

/// Functional API to try to peek TLS:CH from an existing I/O input,
/// returning the stream as-is with the read data prefixed from memory.
///
/// Timeouts use [`PeekTimeoutPolicy::FailOpen`] for backward compatibility. Use
/// [`peek_client_hello_from_input_with_timeout_policy`] to select an explicit
/// policy.
///
/// Use [`PeekTlsClientHelloService`] if you prefer it as a rama [`Service`] instead.
pub async fn peek_client_hello_from_input<PeekableInput>(
    input: PeekableInput,
    timeout: Option<Duration>,
) -> Result<
    (
        PeekableInput::Mapped<TlsClientHelloPrefixedIo<PeekableInput::PeekIo>>,
        Option<ClientHello>,
    ),
    std::io::Error,
>
where
    PeekableInput: PeekIoProvider<PeekIo: Unpin>,
{
    peek_client_hello_from_input_with_timeout_policy(input, timeout, PeekTimeoutPolicy::FailOpen)
        .await
}

/// Functional API to try to peek a TLS ClientHello with an explicit timeout
/// policy, returning the stream with every consumed byte prefixed from memory.
///
/// A definitive non-TLS or malformed prefix returns `Ok((input, None))` under
/// either policy. An inconclusive timeout returns a timed-out [`std::io::Error`]
/// when [`PeekTimeoutPolicy::FailClosed`] is selected.
pub async fn peek_client_hello_from_input_with_timeout_policy<PeekableInput>(
    mut input: PeekableInput,
    timeout: Option<Duration>,
    timeout_policy: PeekTimeoutPolicy,
) -> Result<
    (
        PeekableInput::Mapped<TlsClientHelloPrefixedIo<PeekableInput::PeekIo>>,
        Option<ClientHello>,
    ),
    std::io::Error,
>
where
    PeekableInput: PeekIoProvider<PeekIo: Unpin>,
{
    let mut peek_buf = [0u8; TLS_HEADER_PEEK_LEN];
    let peekable_io = input.peek_io_mut();

    let start = Instant::now();

    // Fail fast on non-TLS prefixes (see `tls_record_header_verdict`) instead of
    // blocking until the full 5-byte window arrives; no attempt cap so a
    // fragmented but still-plausible TLS header keeps reading (bounded by the
    // buffer, EOF, and the optional timeout).
    let PeekOutput {
        data,
        peek_size,
        stop_reason,
    } = peek_input_until_verdict_with_options(
        peekable_io,
        &mut peek_buf,
        0,
        timeout,
        None,
        super::peek::tls_record_header_verdict,
    )
    .await;

    if stop_reason == PeekStopReason::Timeout && timeout_policy == PeekTimeoutPolicy::FailClosed {
        return Err(PeekTimeoutError::new().into());
    }

    let is_tls = data.is_some();
    tracing::trace!("tls prefix header read (is tls: {is_tls})");

    if !is_tls {
        if TLS_HEADER_PEEK_LEN.saturating_sub(peek_size) > 0 {
            tracing::trace!(
                "move tls peek buffer cursor due to reading not enough (read: {peek_size})"
            );
        }

        let prefix_data = HeapReader::from(&peek_buf[..peek_size.min(TLS_HEADER_PEEK_LEN)]);
        let peeked_input = input.map_peek_io(|io| PrefixedIo::new(prefix_data, io));

        tracing::trace!("return early for non-tls traffic: missing peek header");
        return Ok((peeked_input, None));
    }

    // Grow the peek buffer with the bytes actually received (up to a hard cap)
    // rather than pre-allocating the peer-declared record length: memory tracks
    // real input, while the cap still bounds a very large — or lying — peer,
    // which then falls through as non-ClientHello. The handshake-length-aware
    // classifier returns `Match` exactly when the hello is complete, so the grow
    // loop never over-reads past it (an extra read would block on the awaited
    // ServerHello). Modern ClientHellos (Firefox/Chrome with post-quantum key
    // shares, GREASE, ALPS, full cipher lists) routinely exceed 2 KiB, hence the
    // 16 KiB ceiling (RFC 8446 §5.1: a record payload is at most 2^14 bytes).
    const MAX_TLS_RECORD: usize = kib(16) + TLS_HEADER_PEEK_LEN;
    let read_chunk = NonZeroUsize::new(1024).unwrap_or(NonZeroUsize::MIN);

    let new_timeout = timeout.map(|t| t.saturating_sub(start.elapsed()));

    let mut v = Vec::with_capacity(read_chunk.get() + TLS_HEADER_PEEK_LEN);
    v.extend_from_slice(&peek_buf[..]);

    let output = peek_input_until_verdict_growing_with_output(
        peekable_io,
        &mut v,
        MAX_TLS_RECORD,
        read_chunk,
        new_timeout,
        |buffer| match parse_client_hello_handshake_prefix(buffer) {
            ClientHelloHandshakePrefix::Complete(hello) => PeekVerdict::Match(hello),
            ClientHelloHandshakePrefix::Incomplete => PeekVerdict::NeedMore,
            ClientHelloHandshakePrefix::Invalid => PeekVerdict::Reject,
        },
    )
    .await;

    if output.stop_reason == PeekStopReason::Timeout
        && timeout_policy == PeekTimeoutPolicy::FailClosed
    {
        return Err(PeekTimeoutError::new().into());
    }

    let prefix_data = HeapReader::from(v);
    let peeked_input = input.map_peek_io(|io| PrefixedIo::new(prefix_data, io));

    Ok((peeked_input, output.data))
}

impl<PeekableInput, Output, S, F> Service<PeekableInput> for PeekTlsClientHelloService<S, F>
where
    PeekableInput: PeekIoProvider<PeekIo: Unpin>,
    Output: Send + 'static,
    S: Service<
            InputWithClientHello<
                PeekableInput::Mapped<TlsClientHelloPrefixedIo<PeekableInput::PeekIo>>,
            >,
            Output = Output,
            Error: Into<BoxError>,
        >,
    F: Service<
            PeekableInput::Mapped<TlsClientHelloPrefixedIo<PeekableInput::PeekIo>>,
            Output = Output,
            Error: Into<BoxError>,
        >,
{
    type Output = Output;
    type Error = BoxError;

    async fn serve(&self, input: PeekableInput) -> Result<Self::Output, Self::Error> {
        let (peeked_input, maybe_client_hello) = peek_client_hello_from_input_with_timeout_policy(
            input,
            self.peek_timeout,
            self.peek_timeout_policy,
        )
        .await
        .context("I/O error while peeking TLS:CH from existing input")?;

        if let Some(client_hello) = maybe_client_hello {
            self.service
                .serve(InputWithClientHello {
                    input: peeked_input,
                    client_hello,
                })
                .await
                .map_err(Into::into)
        } else {
            self.fallback.serve(peeked_input).await.map_err(Into::into)
        }
    }
}

const TLS_HEADER_PEEK_LEN: usize = 5;

/// [`PrefixedIo`] alias used by [`PeekTlsClientHelloService`].
pub type TlsClientHelloPrefixedIo<S> = PrefixedIo<HeapReader, S>;

/// An `input` with a Client Hello (tls) attached to it,
/// usually used in combination with [`PeekTlsClientHelloService`].
#[derive(Debug, Clone)]
pub struct InputWithClientHello<Input> {
    pub input: Input,
    pub client_hello: ClientHello,
}

#[cfg(test)]
mod test {
    use rama_core::{
        ServiceInput,
        service::{RejectError, service_fn},
    };
    use std::{
        convert::Infallible,
        sync::{
            Arc,
            atomic::{AtomicUsize, Ordering},
        },
    };
    use tokio::io::{AsyncReadExt as _, AsyncWriteExt as _};

    use rama_core::io::Io;

    use super::*;

    const CH_ONE_ONE_ONE_ONE: &[u8] = &[
        0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03, 0x02, 0x15, 0xfd, 0xe2,
        0x92, 0xc0, 0x46, 0x9f, 0x92, 0xbe, 0xd7, 0xe9, 0x1a, 0x3c, 0x50, 0x5e, 0x55, 0x49, 0x17,
        0xa6, 0xf8, 0xa5, 0xca, 0xa4, 0x6d, 0x60, 0xcc, 0xea, 0xf7, 0x25, 0xf0, 0x6e, 0x20, 0x41,
        0x20, 0x18, 0x66, 0x5c, 0xae, 0x08, 0xb0, 0x10, 0x96, 0x3c, 0xad, 0xb4, 0x13, 0xe1, 0x92,
        0xce, 0x96, 0xad, 0x9d, 0x45, 0x05, 0xb7, 0xa6, 0x4c, 0x01, 0x71, 0x08, 0x74, 0x0d, 0x1f,
        0x35, 0x00, 0x2a, 0x3a, 0x3a, 0x13, 0x01, 0x13, 0x02, 0x13, 0x03, 0xc0, 0x2c, 0xc0, 0x2b,
        0xcc, 0xa9, 0xc0, 0x30, 0xc0, 0x2f, 0xcc, 0xa8, 0xc0, 0x0a, 0xc0, 0x09, 0xc0, 0x14, 0xc0,
        0x13, 0x00, 0x9d, 0x00, 0x9c, 0x00, 0x35, 0x00, 0x2f, 0xc0, 0x08, 0xc0, 0x12, 0x00, 0x0a,
        0x01, 0x00, 0x01, 0x89, 0xda, 0xda, 0x00, 0x00, 0x00, 0x00, 0x00, 0x14, 0x00, 0x12, 0x00,
        0x00, 0x0f, 0x6f, 0x6e, 0x65, 0x2e, 0x6f, 0x6e, 0x65, 0x2e, 0x6f, 0x6e, 0x65, 0x2e, 0x6f,
        0x6e, 0x65, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01, 0x00, 0x00, 0x0a, 0x00, 0x0c,
        0x00, 0x0a, 0xfa, 0xfa, 0x00, 0x1d, 0x00, 0x17, 0x00, 0x18, 0x00, 0x19, 0x00, 0x0b, 0x00,
        0x02, 0x01, 0x00, 0x00, 0x05, 0x00, 0x05, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0d, 0x00,
        0x16, 0x00, 0x14, 0x04, 0x03, 0x08, 0x04, 0x04, 0x01, 0x05, 0x03, 0x08, 0x05, 0x08, 0x05,
        0x05, 0x01, 0x08, 0x06, 0x06, 0x01, 0x02, 0x01, 0x00, 0x12, 0x00, 0x00, 0x00, 0x33, 0x00,
        0x2b, 0x00, 0x29, 0xfa, 0xfa, 0x00, 0x01, 0x00, 0x00, 0x1d, 0x00, 0x20, 0x7c, 0xe1, 0xc6,
        0xc2, 0x01, 0x69, 0x42, 0xba, 0x2b, 0xec, 0x07, 0x2f, 0x04, 0xbd, 0xb6, 0x2a, 0x7e, 0x04,
        0x6b, 0x96, 0x98, 0x51, 0x4e, 0x80, 0xb3, 0x2a, 0x4c, 0x4f, 0x1f, 0x39, 0x82, 0x2b, 0x00,
        0x2d, 0x00, 0x02, 0x01, 0x01, 0x00, 0x2b, 0x00, 0x0b, 0x0a, 0x6a, 0x6a, 0x03, 0x04, 0x03,
        0x03, 0x03, 0x02, 0x03, 0x01, 0x00, 0x1b, 0x00, 0x03, 0x02, 0x00, 0x01, 0x3a, 0x3a, 0x00,
        0x01, 0x00, 0x00, 0x15, 0x00, 0xd3, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    ];

    const TLS_BUT_NO_SNI: &[u8] = &[
        0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03, 0x28, 0x5b, 0x8f, 0x90,
        0x22, 0x2a, 0x90, 0x95, 0x89, 0xa9, 0x62, 0x1f, 0xdb, 0x68, 0xbe, 0x4c, 0x0e, 0xdf, 0xe4,
        0x76, 0x50, 0x48, 0xa5, 0x40, 0x56, 0x5f, 0x9a, 0xba, 0x19, 0x29, 0x66, 0xdd, 0x20, 0x7a,
        0x7f, 0x7e, 0xc7, 0xbd, 0xfb, 0x88, 0x07, 0xd9, 0xf5, 0x99, 0xfa, 0xf3, 0x0d, 0x37, 0x30,
        0x52, 0x4d, 0x44, 0xe4, 0x26, 0xc0, 0xd1, 0x9a, 0xcd, 0x78, 0xf6, 0x7a, 0xf1, 0x7a, 0x66,
        0xe1, 0x00, 0x3e, 0x13, 0x02, 0x13, 0x03, 0x13, 0x01, 0xc0, 0x2c, 0xc0, 0x30, 0x00, 0x9f,
        0xcc, 0xa9, 0xcc, 0xa8, 0xcc, 0xaa, 0xc0, 0x2b, 0xc0, 0x2f, 0x00, 0x9e, 0xc0, 0x24, 0xc0,
        0x28, 0x00, 0x6b, 0xc0, 0x23, 0xc0, 0x27, 0x00, 0x67, 0xc0, 0x0a, 0xc0, 0x14, 0x00, 0x39,
        0xc0, 0x09, 0xc0, 0x13, 0x00, 0x33, 0x00, 0x9d, 0x00, 0x9c, 0x00, 0x3d, 0x00, 0x3c, 0x00,
        0x35, 0x00, 0x2f, 0x00, 0xff, 0x01, 0x00, 0x01, 0x75, 0x00, 0x0b, 0x00, 0x04, 0x03, 0x00,
        0x01, 0x02, 0x00, 0x0a, 0x00, 0x16, 0x00, 0x14, 0x00, 0x1d, 0x00, 0x17, 0x00, 0x1e, 0x00,
        0x19, 0x00, 0x18, 0x01, 0x00, 0x01, 0x01, 0x01, 0x02, 0x01, 0x03, 0x01, 0x04, 0x00, 0x10,
        0x00, 0x0e, 0x00, 0x0c, 0x02, 0x68, 0x32, 0x08, 0x68, 0x74, 0x74, 0x70, 0x2f, 0x31, 0x2e,
        0x31, 0x00, 0x16, 0x00, 0x00, 0x00, 0x17, 0x00, 0x00, 0x00, 0x31, 0x00, 0x00, 0x00, 0x0d,
        0x00, 0x2a, 0x00, 0x28, 0x04, 0x03, 0x05, 0x03, 0x06, 0x03, 0x08, 0x07, 0x08, 0x08, 0x08,
        0x09, 0x08, 0x0a, 0x08, 0x0b, 0x08, 0x04, 0x08, 0x05, 0x08, 0x06, 0x04, 0x01, 0x05, 0x01,
        0x06, 0x01, 0x03, 0x03, 0x03, 0x01, 0x03, 0x02, 0x04, 0x02, 0x05, 0x02, 0x06, 0x02, 0x00,
        0x2b, 0x00, 0x05, 0x04, 0x03, 0x04, 0x03, 0x03, 0x00, 0x2d, 0x00, 0x02, 0x01, 0x01, 0x00,
        0x33, 0x00, 0x26, 0x00, 0x24, 0x00, 0x1d, 0x00, 0x20, 0xe0, 0xb9, 0xfb, 0x5a, 0xd5, 0x60,
        0x30, 0x39, 0xad, 0xfb, 0xd3, 0x94, 0xa2, 0xff, 0x08, 0x71, 0x9b, 0xcc, 0x6f, 0xbe, 0x9e,
        0xcc, 0x7b, 0xad, 0x3c, 0xd0, 0xde, 0xe8, 0x3e, 0x5d, 0xba, 0x6b, 0x00, 0x15, 0x00, 0xca,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    ];

    #[tokio::test]
    async fn test_client_hello_peek_service() {
        let tls_service = service_fn(async |input: InputWithClientHello<_>| {
            let sni = input
                .client_hello
                .ext_server_name()
                .map(ToString::to_string);
            Ok::<_, Infallible>(sni)
        });
        let plain_service = service_fn(async || Ok::<_, Infallible>(Some("plain".to_owned())));

        let peek_tls_svc = PeekTlsClientHelloService::new(tls_service).with_fallback(plain_service);
        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(b"".to_vec())))
            .await
            .unwrap();
        assert_eq!(Some("plain".to_owned()), response);

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(
                CH_ONE_ONE_ONE_ONE.to_vec(),
            )))
            .await
            .unwrap();
        assert_eq!(Some("one.one.one.one".to_owned()), response);

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(b"foo".to_vec())))
            .await
            .unwrap();
        assert_eq!(Some("plain".to_owned()), response);

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(b"foobar".to_vec())))
            .await
            .unwrap();
        assert_eq!(Some("plain".to_owned()), response);

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(
                TLS_BUT_NO_SNI.to_vec(),
            )))
            .await
            .unwrap();
        assert_eq!(None, response);
    }

    #[tokio::test]
    async fn test_peek_router_read_eof() {
        async fn tls_service_fn(
            InputWithClientHello {
                mut input,
                client_hello,
            }: InputWithClientHello<impl Io + Unpin>,
        ) -> Result<&'static str, BoxError> {
            let mut v = Vec::default();
            _ = input.read_to_end(&mut v).await?;
            assert_eq!(CH_ONE_ONE_ONE_ONE, v);
            assert!(client_hello.ext_server_name().is_some());
            assert_eq!(
                "one.one.one.one",
                client_hello.ext_server_name().unwrap().to_string()
            );
            Ok("ok")
        }
        let tls_service = service_fn(tls_service_fn);

        let peek_tls_svc =
            PeekTlsClientHelloService::new(tls_service).with_fallback(RejectService::<
                &'static str,
                RejectError,
            >::new(
                RejectError::default()
            ));

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(
                CH_ONE_ONE_ONE_ONE.to_vec(),
            )))
            .await
            .unwrap();
        assert_eq!("ok", response);
    }

    #[tokio::test]
    async fn test_peek_router_read_no_tls_eof() {
        let cases = ["", "foo", "abcd", "abcde", "foobarbazbananas"];
        for content in cases {
            async fn tls_service_fn() -> Result<Vec<u8>, BoxError> {
                Ok("tls".as_bytes().to_vec())
            }
            let tls_service = service_fn(tls_service_fn);

            async fn plain_service_fn(mut stream: impl Io + Unpin) -> Result<Vec<u8>, BoxError> {
                let mut v = Vec::default();
                _ = stream.read_to_end(&mut v).await?;
                Ok(v)
            }
            let plain_service = service_fn(plain_service_fn);

            let peek_tls_svc =
                PeekTlsClientHelloService::new(tls_service).with_fallback(plain_service);

            let response = peek_tls_svc
                .serve(ServiceInput::new(std::io::Cursor::new(
                    content.as_bytes().to_vec(),
                )))
                .await
                .unwrap();

            assert_eq!(content.as_bytes(), &response[..]);
        }
    }

    #[tokio::test]
    async fn test_partial_client_hello_does_not_prefix_zero_padding() {
        const SPLIT_AT: usize = 64;
        const PEEK_TIMEOUT: Duration = Duration::from_millis(10);

        let (mut client, server) = tokio::io::duplex(CH_ONE_ONE_ONE_ONE.len());
        let (prefix_sent_tx, prefix_sent_rx) = tokio::sync::oneshot::channel();
        let (continue_tx, continue_rx) = tokio::sync::oneshot::channel();
        let writer = tokio::spawn(async move {
            client
                .write_all(&CH_ONE_ONE_ONE_ONE[..SPLIT_AT])
                .await
                .unwrap();
            prefix_sent_tx.send(()).unwrap();
            continue_rx.await.unwrap();
            client
                .write_all(&CH_ONE_ONE_ONE_ONE[SPLIT_AT..])
                .await
                .unwrap();
        });
        prefix_sent_rx.await.unwrap();

        let (mut input, client_hello) =
            peek_client_hello_from_input(ServiceInput::new(server), Some(PEEK_TIMEOUT))
                .await
                .unwrap();
        assert!(client_hello.is_none());
        continue_tx.send(()).unwrap();

        let mut bytes = Vec::new();
        input.read_to_end(&mut bytes).await.unwrap();
        writer.await.unwrap();

        assert_eq!(CH_ONE_ONE_ONE_ONE, bytes);
    }

    #[tokio::test]
    async fn partial_client_hello_fail_closed_returns_timeout_without_fallback() {
        const SPLIT_AT: usize = 64;

        let fallback_calls = Arc::new(AtomicUsize::new(0));
        let fallback_calls_for_service = Arc::clone(&fallback_calls);
        let fallback = service_fn(move || {
            fallback_calls_for_service.fetch_add(1, Ordering::SeqCst);
            async { Ok::<_, Infallible>("fallback") }
        });
        let router =
            PeekTlsClientHelloService::new(service_fn(async || Ok::<_, Infallible>("tls")))
                .with_peek_timeout(Duration::from_millis(10))
                .with_peek_timeout_policy(PeekTimeoutPolicy::FailClosed)
                .with_fallback(fallback);
        let (mut client, server) = tokio::io::duplex(CH_ONE_ONE_ONE_ONE.len());
        client
            .write_all(&CH_ONE_ONE_ONE_ONE[..SPLIT_AT])
            .await
            .unwrap();

        let error = router.serve(ServiceInput::new(server)).await.unwrap_err();

        assert!(error_chain_has_peek_timeout(error.as_ref()));
        assert_eq!(0, fallback_calls.load(Ordering::SeqCst));
    }

    #[tokio::test]
    async fn malformed_client_hello_falls_back_under_both_timeout_policies() {
        let malformed = [
            0x16, 0x03, 0x03, 0x00, 0x06, 0x02, 0x00, 0x00, 0x02, 0xaa, 0xbb,
        ];

        for policy in [PeekTimeoutPolicy::FailOpen, PeekTimeoutPolicy::FailClosed] {
            let router =
                PeekTlsClientHelloService::new(service_fn(async || Ok::<_, Infallible>("tls")))
                    .with_peek_timeout(Duration::from_millis(10))
                    .with_peek_timeout_policy(policy)
                    .with_fallback(service_fn(async || Ok::<_, Infallible>("fallback")));

            let response = router
                .serve(ServiceInput::new(std::io::Cursor::new(malformed.to_vec())))
                .await
                .unwrap();
            assert_eq!("fallback", response);
        }
    }

    fn error_chain_has_peek_timeout(mut error: &(dyn std::error::Error + 'static)) -> bool {
        loop {
            if error.downcast_ref::<PeekTimeoutError>().is_some()
                || error
                    .downcast_ref::<std::io::Error>()
                    .is_some_and(|error| error.kind() == std::io::ErrorKind::TimedOut)
            {
                return true;
            }
            let Some(source) = error.source() else {
                return false;
            };
            error = source;
        }
    }

    #[tokio::test]
    async fn test_peek_router_read_tls_no_sni_eof() {
        async fn tls_service_fn(
            InputWithClientHello {
                mut input,
                client_hello,
            }: InputWithClientHello<impl Io + Unpin>,
        ) -> Result<&'static str, BoxError> {
            let mut v = Vec::default();
            _ = input.read_to_end(&mut v).await?;
            assert_eq!(TLS_BUT_NO_SNI, v);
            assert!(client_hello.ext_server_name().is_none());
            Ok("ok")
        }
        let tls_service = service_fn(tls_service_fn);

        let peek_tls_svc =
            PeekTlsClientHelloService::new(tls_service).with_fallback(RejectService::<
                &'static str,
                RejectError,
            >::new(
                RejectError::default()
            ));

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(
                TLS_BUT_NO_SNI.to_vec(),
            )))
            .await
            .unwrap();
        assert_eq!("ok", response);
    }
}