summaryrefslogtreecommitdiffhomepage
path: root/https.cpp
blob: 523acb574f0f68145e60875913a018ecb84ce5c7 (plain)
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
#include "https.h"

#include "config.h"
#include "server.h"
#include "response.h"

#include "libreichwein/file.h"

#include <openssl/ssl.h>
#include <openssl/crypto.h>

#include <boost/asio/buffer.hpp>
#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>
#include <boost/asio/dispatch.hpp>
#include <boost/asio/ssl/context.hpp>
#ifdef BOOST_LATEST
#include <boost/beast/ssl.hpp>
#else
#include <boost/asio/ip/tcp.hpp>
#include <boost/asio/ssl/stream.hpp>
#include <boost/asio/bind_executor.hpp>
#endif
#include <boost/asio/strand.hpp>
#include <boost/config.hpp>

#include <algorithm>
#include <cstddef>
#include <cstdlib>
#include <filesystem>
#include <functional>
#include <iostream>
#include <memory>
#include <optional>
#include <string>
#include <thread>
#include <vector>

namespace fs = std::filesystem;
namespace beast = boost::beast;         // from <boost/beast.hpp>
namespace http = beast::http;           // from <boost/beast/http.hpp>
namespace net = boost::asio;            // from <boost/asio.hpp>
namespace ssl = boost::asio::ssl;       // from <boost/asio/ssl.hpp>
using tcp = boost::asio::ip::tcp;       // from <boost/asio/ip/tcp.hpp>
using namespace Reichwein;

namespace {

//------------------------------------------------------------------------------

// Report a failure
void fail(
#ifdef BOOST_LATEST
     beast::error_code ec,
#else
     boost::system::error_code ec,
#endif
     char const* what)
{
#ifdef BOOST_LATEST
    // ssl::error::stream_truncated, also known as an SSL "short read",
    // indicates the peer closed the connection without performing the
    // required closing handshake (for example, Google does this to
    // improve performance). Generally this can be a security issue,
    // but if your communication protocol is self-terminated (as
    // it is with both HTTP and WebSocket) then you may simply
    // ignore the lack of close_notify.
    //
    // https://github.com/boostorg/beast/issues/38
    //
    // https://security.stackexchange.com/questions/91435/how-to-handle-a-malicious-ssl-tls-shutdown
    //
    // When a short read would cut off the end of an HTTP message,
    // Beast returns the error beast::http::error::partial_message.
    // Therefore, if we see a short read here, it has occurred
    // after the message has been completed, so it is safe to ignore it.

    if(ec == net::ssl::error::stream_truncated)
        return;
#endif

    std::cerr << what << ": " << ec.message() << "\n";
}

// Handles an HTTP server connection
class session : public std::enable_shared_from_this<session>
{
#ifdef BOOST_LATEST
 beast::ssl_stream<beast::tcp_stream> stream_;
#else
 tcp::socket socket_;
 ssl::stream<tcp::socket&> stream_;
 boost::asio::strand<boost::asio::io_context::executor_type> strand_;
#endif
 beast::flat_buffer buffer_;
 Server& m_server;
 std::optional<http::request_parser<http::string_body>> parser_; // need to reset parser every time, no other mechanism currently
 http::request<http::string_body> req_;
 std::shared_ptr<response_type> res_; // std::shared_ptr<void>

 void handle_request(::Server& server, request_type&& req)
 {
#ifdef BOOST_LATEST
  beast::get_lowest_layer(stream_).expires_after(std::chrono::seconds(300)); // timeout on write by server much longer than read timeout from client
#else
  // beast::get_lowest_layer<tcp::socket>(stream_).expires_after(std::chrono::seconds(300)); // not supported by boost
#endif
  auto sp = std::make_shared<response_type>(generate_response(req, server));

  res_ = sp;

  // Write the response
#ifdef BOOST_LATEST
  http::async_write(
      stream_,
      *sp,
      beast::bind_front_handler(
          &session::on_write,
          shared_from_this(),
          sp->need_eof()));
#else
  http::async_write(
      stream_,
      *sp,
      boost::asio::bind_executor(
          strand_,
          std::bind(
              &session::on_write,
              shared_from_this(),
              std::placeholders::_1,
              std::placeholders::_2,
              sp->need_eof())));
#endif
 }
public:
    // Take ownership of the socket
    explicit
    session(
#ifdef BOOST_LATEST
        tcp::socket&& socket,
#else
        tcp::socket socket,
#endif
        ssl::context& ctx,
        Server& server)
#ifdef BOOST_LATEST
        : stream_(std::move(socket), ctx)
#else
        : socket_(std::move(socket))
        , stream_(socket_, ctx)
        , strand_(socket_.get_executor())
#endif
        , m_server(server)
    {
    }

    // Start the asynchronous operation
    void
    run()
    {
#ifdef BOOST_LATEST
        // We need to be executing within a strand to perform async operations
        // on the I/O objects in this session.
        net::dispatch(
            stream_.get_executor(),
            beast::bind_front_handler(
                &session::on_run,
                shared_from_this()));
#else
        stream_.async_handshake(
            ssl::stream_base::server,
            boost::asio::bind_executor(
                strand_,
                std::bind(
                    &session::on_handshake,
                    shared_from_this(),
                    std::placeholders::_1)));
#endif
    }

#ifdef BOOST_LATEST
    void
    on_run()
    {
        // Set the timeout.
        beast::get_lowest_layer(stream_).expires_after(
            std::chrono::seconds(30));

        // Perform the SSL handshake
        stream_.async_handshake(
            ssl::stream_base::server,
            beast::bind_front_handler(
                &session::on_handshake,
                shared_from_this()));
    }
#endif

    void
    on_handshake(
#ifdef BOOST_LATEST
                 beast::error_code ec
#else
                 boost::system::error_code ec
#endif
                 )
    {
        if(ec)
            return fail(ec, "https handshake");

        do_read();
    }

    void
    do_read()
    {
        // Make the request empty before reading,
        // otherwise the operation behavior is undefined.
        req_ = {};
       
        // this is the way to reset the parser. it's necessary.
        // https://github.com/boostorg/beast/issues/927
        parser_.emplace();
        parser_->body_limit(1000000000); // 1GB limit

#ifdef BOOST_LATEST
        // Set the timeout.
        beast::get_lowest_layer(stream_).expires_after(std::chrono::seconds(30));

        // Read a request
        http::async_read(stream_, buffer_, *parser_,
            beast::bind_front_handler(
                &session::on_read,
                shared_from_this()));
#else
        http::async_read(stream_, buffer_, *parser_,
            boost::asio::bind_executor(
                strand_,
                std::bind(
                    &session::on_read,
                    shared_from_this(),
                    std::placeholders::_1,
                    std::placeholders::_2)));
#endif
    }

    void
    on_read(
#ifdef BOOST_LATEST
        beast::error_code ec,
#else
        boost::system::error_code ec,
#endif
        std::size_t bytes_transferred)
    {
        boost::ignore_unused(bytes_transferred);

        // This means they closed the connection
        if (ec == http::error::end_of_stream)
            return do_close();

        if (ec == http::error::partial_message)
         return; // ignore

        if (ec)
            return fail(ec, "https read");

        req_ = parser_->get();
        
        // Send the response
        handle_request(m_server, std::move(req_));
    }

    void
    on_write(
#ifdef BOOST_LATEST
        bool close,
        beast::error_code ec,
        std::size_t bytes_transferred
#else
        boost::system::error_code ec,
        std::size_t bytes_transferred,
        bool close
#endif
        )
    {
        boost::ignore_unused(bytes_transferred);

        if(ec)
            return fail(ec, "https write");

        if(close)
        {
            // This means we should close the connection, usually because
            // the response indicated the "Connection: close" semantic.
            return do_close();
        }

        // We're done with the response so delete it
        res_ = nullptr;

        // Read another request
        do_read();
    }

    void
    do_close()
    {
#ifdef BOOST_LATEST
        // Set the timeout.
        beast::get_lowest_layer(stream_).expires_after(std::chrono::seconds(30));

        // Perform the SSL shutdown
        stream_.async_shutdown(
            beast::bind_front_handler(
                &session::on_shutdown,
                shared_from_this()));
#else
        stream_.async_shutdown(
            boost::asio::bind_executor(
                strand_,
                std::bind(
                    &session::on_shutdown,
                    shared_from_this(),
                    std::placeholders::_1)));
#endif
    }

    void
    on_shutdown(beast::error_code ec)
    {
        if(ec)
            return fail(ec, "https shutdown");

        // At this point the connection is closed gracefully
    }
};

//------------------------------------------------------------------------------

// Accepts incoming connections and launches the sessions
class listener : public std::enable_shared_from_this<listener>
{
#ifdef BOOST_LATEST
    net::io_context& ioc_;
#endif
    ssl::context& ctx_;
    tcp::acceptor acceptor_;
#ifndef BOOST_LATEST
    tcp::socket socket_;
#endif
    ::Server& m_server;

public:
    listener(
        net::io_context& ioc,
        ssl::context& ctx,
        tcp::endpoint endpoint,
        Server& server) :
#ifdef BOOST_LATEST
        ioc_(ioc),
#endif
        ctx_(ctx)
        , acceptor_(ioc)
#ifndef BOOST_LATEST
        , socket_(ioc)
#endif
        , m_server(server)
    {
#ifdef BOOST_LATEST
        beast::error_code ec;
#else
        boost::system::error_code ec;
#endif

        // Open the acceptor
        acceptor_.open(endpoint.protocol(), ec);
        if(ec)
        {
            fail(ec, "https open");
            return;
        }

        // Allow address reuse
        acceptor_.set_option(net::socket_base::reuse_address(true), ec);
        if(ec)
        {
            fail(ec, "https set_option");
            return;
        }

        // Bind to the server address
        acceptor_.bind(endpoint, ec);
        if(ec)
        {
            fail(ec, "https bind");
            return;
        }

        // Start listening for connections
        acceptor_.listen(
            net::socket_base::max_listen_connections, ec);
        if(ec)
        {
            fail(ec, "https listen");
            return;
        }
    }

    // Start accepting incoming connections
    void
    run()
    {
#ifndef BOOST_LATEST
     if(! acceptor_.is_open())
            return;
#endif
        do_accept();
    }

private:
    void
    do_accept()
    {
        // The new connection gets its own strand
#ifdef BOOST_LATEST
        acceptor_.async_accept(
            net::make_strand(ioc_),
            beast::bind_front_handler(
                &listener::on_accept,
                shared_from_this()));
#else
        acceptor_.async_accept(
            socket_,
            std::bind(
                &listener::on_accept,
                shared_from_this(),
                std::placeholders::_1));
#endif
    }

    void
#ifdef BOOST_LATEST
    on_accept(beast::error_code ec, tcp::socket socket)
#else
    on_accept(boost::system::error_code ec)
#endif
    {
        if(ec)
        {
            fail(ec, "https accept");
        }
        else
        {
            // Create the session and run it
            std::make_shared<session>(
#ifdef BOOST_LATEST
                std::move(socket),
#else
                std::move(socket_),
#endif
                ctx_,
                m_server)->run();
        }

        // Accept another connection
        do_accept();
    }
};

/*  Load a signed certificate into the ssl context, and configure
    the context for use with a server.
*/
void load_server_certificate(boost::asio::ssl::context& ctx, const fs::path& cert_path, const fs::path& key_path)
{
    /*
        The certificate was generated from CMD.EXE on Windows 10 using:

        winpty openssl dhparam -out dh.pem 2048
        winpty openssl req -newkey rsa:4096 -sha256 -nodes -keyout key.pem -x509 -days 10000 -out cert.pem -subj "//C=DE\ST=BY\L=Munich\O=Reichwein\CN=reichwein.it"
    */

    std::string const dh =
        "-----BEGIN DH PARAMETERS-----\n"
        "MIIBCAKCAQEArzQc5mpm0Fs8yahDeySj31JZlwEphUdZ9StM2D8+Fo7TMduGtSi+\n"
        "/HRWVwHcTFAgrxVdm+dl474mOUqqaz4MpzIb6+6OVfWHbQJmXPepZKyu4LgUPvY/\n"
        "4q3/iDMjIS0fLOu/bLuObwU5ccZmDgfhmz1GanRlTQOiYRty3FiOATWZBRh6uv4u\n"
        "tff4A9Bm3V9tLx9S6djq31w31Gl7OQhryodW28kc16t9TvO1BzcV3HjRPwpe701X\n"
        "oEEZdnZWANkkpR/m/pfgdmGPU66S2sXMHgsliViQWpDCYeehrvFRHEdR9NV+XJfC\n"
        "QMUk26jPTIVTLfXmmwU0u8vUkpR7LQKkwwIBAg==\n"
        "-----END DH PARAMETERS-----\n";
    
    ctx.set_options(
        boost::asio::ssl::context::default_workarounds |
        boost::asio::ssl::context::no_sslv2 |
        boost::asio::ssl::context::single_dh_use);

    std::string cert;
    if (cert_path.empty()) {
     // use dummy self signed certificate. Will be replaced by real
     // certificate if configured upon respective session
     cert =
      "-----BEGIN CERTIFICATE-----\n"
      "MIIDnTCCAoWgAwIBAgIULkYtO+2Ddeg+qLZ+aDQpmA5b4L0wDQYJKoZIhvcNAQEL\n"
      "BQAwXjELMAkGA1UEBhMCREUxEDAOBgNVBAgMB0JhdmFyaWExDzANBgNVBAcMBk11\n"
      "bmljaDEVMBMGA1UECgwMUmVpY2h3ZWluIElUMRUwEwYDVQQDDAxyZWljaHdlaW4u\n"
      "aXQwHhcNMjAwNDA1MDgwNzIyWhcNNDcwODIyMDgwNzIyWjBeMQswCQYDVQQGEwJE\n"
      "RTEQMA4GA1UECAwHQmF2YXJpYTEPMA0GA1UEBwwGTXVuaWNoMRUwEwYDVQQKDAxS\n"
      "ZWljaHdlaW4gSVQxFTATBgNVBAMMDHJlaWNod2Vpbi5pdDCCASIwDQYJKoZIhvcN\n"
      "AQEBBQADggEPADCCAQoCggEBALJNb0WLbz+xP+YITMMk+eeK/SIOCRFs/9aZIAyK\n"
      "ParGauxa+8d25mlfJTAo6/G0h3sA240JHyNpOzVOogPU+v4dRWyGO0w5vHVD0caB\n"
      "rDb1eEfmLtqfKLLUL9iPDReUh6WAE7qoNDtfoT551uSMIae1cpPUduVTnSkEgw8k\n"
      "NjJSHYT800jSB2R+e7tJG3ErXDM63R3B8RbitZPoWACjpBxDT+Qrj0fBFS4AWw6b\n"
      "z09uitv0RrgI6CW7xRh3UAdRwEBGHiU6HTIthX6LNgez1UL0sfu1iZ22wNmYZP/S\n"
      "sL3b20WtSH9LN2PRJ4q3AGt6RMbmSGr65ljha9xkTFna0Y8CAwEAAaNTMFEwHQYD\n"
      "VR0OBBYEFKd5/MGFZUAUV502vJ/Kcswax8WVMB8GA1UdIwQYMBaAFKd5/MGFZUAU\n"
      "V502vJ/Kcswax8WVMA8GA1UdEwEB/wQFMAMBAf8wDQYJKoZIhvcNAQELBQADggEB\n"
      "AIBS4AfM7wiunQ2UZQQ5A0Un99+BLax9e+h11h/jGeJ+/9maY/E9MK6UG9LXoOv2\n"
      "z32Q7Ta2xKeRu6GC/qupwYJ0Xt3LENOfogsaNCAgxKlAN48LGlRyCTvzWsEMh28j\n"
      "RaelWonh2qQoiryKLVnRwrg8g1Bu4v+V437cIBmeZPxf0spEL9EVqlN+iS8plmel\n"
      "7/F4ULdybKGq39tgicuS7JhnY21ZzOFoq0bWnKBbAeTndmuROdb3pEppxW6pwu0q\n"
      "TFdMrSJE38kiQh2O9IchPQbTZ+Rdj0HE9NxStlrNr5bu6rjikRm50/G3JoXpzYdp\n"
      "AN4ZI2QZ6R6Y+TzDixKecNk=\n"
      "-----END CERTIFICATE-----\n"
      ;
    } else {
     cert = File::getFile(cert_path);
    }

    ctx.use_certificate_chain(
        boost::asio::buffer(cert.data(), cert.size()));

    std::string key;
    if (key_path == "") {
     // use dummy self signed key. Will be replaced by real
     // certificate if configured upon respective session
     key =
      "-----BEGIN PRIVATE KEY-----\n"
      "MIIEvgIBADANBgkqhkiG9w0BAQEFAASCBKgwggSkAgEAAoIBAQCyTW9Fi28/sT/m\n"
      "CEzDJPnniv0iDgkRbP/WmSAMij2qxmrsWvvHduZpXyUwKOvxtId7ANuNCR8jaTs1\n"
      "TqID1Pr+HUVshjtMObx1Q9HGgaw29XhH5i7anyiy1C/Yjw0XlIelgBO6qDQ7X6E+\n"
      "edbkjCGntXKT1HblU50pBIMPJDYyUh2E/NNI0gdkfnu7SRtxK1wzOt0dwfEW4rWT\n"
      "6FgAo6QcQ0/kK49HwRUuAFsOm89Pborb9Ea4COglu8UYd1AHUcBARh4lOh0yLYV+\n"
      "izYHs9VC9LH7tYmdtsDZmGT/0rC929tFrUh/Szdj0SeKtwBrekTG5khq+uZY4Wvc\n"
      "ZExZ2tGPAgMBAAECggEBAK9bJKIa3dCgPB257/TEOtsTgJyrfROcRYkCk9iBZOC9\n"
      "v46wdIrZTwY2wtY4iMPwLoY0c7ijTfJ/nfFxYjmujyK4Gvz+jvcKmWQizP8TrRFo\n"
      "HWFo6o+slFQ8BspO9itIspd7/OtIXgY+qNBO959Sig7sjsEA5eXoc9pRS6vqizq0\n"
      "j4G/UO5Amr/l3ciEJiqMJgZsIVLDKaGlqFTymydSqkB8UHQYWK1kunQxhK4Ldycu\n"
      "hTooQE7tXM0zvoFVV6v1fldV5OFsZk2kPMNtvMO6ZEpOM4rNMlg+vJy8kB1fb3Gs\n"
      "iFE/DCUpZsMSserQMU9/hfrYlndgsFD5Sr1EVGEebhECgYEA1gc9qx+ugdhYTY5j\n"
      "tJDXjOsnw8KY/l/1y+mQ8XNJ9MVdBGy1WB+uWB4teiyJchV49gn2XlKUK2rcCBvZ\n"
      "vC5CwPmFi2t70JezQgnXtDlbR0bARPlRd741i4rBpD7hEiZNCTOd2HFBpUg/CGWN\n"
      "E4n1ksazBm6jvv3Jo6WAa07Z390CgYEA1USrFqmc/fKGQpTCdH0qYZv3hQtrb1TQ\n"
      "9YnrbhtaC0haPpintZKjvhU3tCd1fPuIDXtMAgaaKSyoGiE2aMvLxt1/eV08BkMi\n"
      "kGIss9poYNi5+6ZD9QAHmHJhzZtVGj8U5L8379XmwxAByiBRVVE8CW1X/e6+iJpz\n"
      "+CLgN+zEVlsCgYEAsuOAdtxXJm4meERwL8b0cvNF3Eh1Sf/42MPTAwzCntSrh3w5\n"
      "InvwY/RtPHWnN/ScksEG7BWHhLafTCPDHJdp8hNcvIhNB68UBDln0loyYePP5pag\n"
      "sj4IUSbb7SUlR989elhrMTKQlM5K6QDAJrmjyVdM4S5urL9A3wgAyzAvyP0CgYAO\n"
      "paGuc8WxdzebWQYl4/bGL2UHgSpGwid7xZYiwMQlZDm2dNuHz+NpCaICwHcEN243\n"
      "ptEojnWGAGgnK0LGXcDIDqxTlICr2W6FRgjV7Vkf1aKoUtn1+KOM58YpzdJBdDWm\n"
      "JC/eS+2GVhIZZLDRUDv0VcsmSIBTd3AhiZumm588YwKBgBZfNqfmHAwIP2pM1wml\n"
      "Ck3vaLLvonghj3iQW9CFJ/SqLOnfT4KJkFObR6oGbxY0RtXsCrmSqidIKgDd0Kkq\n"
      "L6QbHp2j3+16GBdmLNUJlfjBTNPJp69IDKztjeCX7/8JZs79p/LAv+I9Sh4lVw4O\n"
      "IrDprlB0yzP5zigcsAZeViYJ\n"
      "-----END PRIVATE KEY-----\n"
      ;
    } else {
     key = File::getFile(key_path);
    }
    ctx.use_private_key(
        boost::asio::buffer(key.data(), key.size()),
        boost::asio::ssl::context::file_format::pem);

    ctx.use_tmp_dh(
        boost::asio::buffer(dh.data(), dh.size()));
}

int ServerNameError(SSL *s, HTTPS::Server::ctx_type& ctx_map)
{
 std::shared_ptr<ssl::context> ctx{ctx_map.at("")};
 SSL_set_SSL_CTX(s, ctx->native_handle());
 return SSL_CLIENT_HELLO_SUCCESS; // OK for now
}

std::string unbracketed(const std::string& s)
{
 if (s.size() >= 2 && s.front() == '[' && s.back() == ']') {
  return s.substr(1, s.size() - 2);
 } else {
  return s;
 }
}

int servername_callback(SSL *s, int *al, void *arg)
{
 HTTPS::Server::ctx_type& ctx_map = *(HTTPS::Server::ctx_type*)arg;

 if (0) { // not really necessary
  int* numbers;
  size_t numbers_size;
  if (SSL_client_hello_get1_extensions_present(s, &numbers, &numbers_size) != 1) {
   std::cout << "Error on SSL_client_hello_get1_extensions_present" << std::endl;
   return ServerNameError(s, ctx_map);
  }
  bool server_name_available {false};
  for (size_t i = 0; i < numbers_size; i++)
   if (numbers[i] == 0)
    server_name_available = true;

  OPENSSL_free(numbers);

  if (!server_name_available) {
   std::cout << "Error: No server_name available at SSL_client_hello_get1_extensions_present" << std::endl;
   return ServerNameError(s, ctx_map);
  }
 }

 const unsigned char* data;
 size_t data_size;
 // 0 is server_name
 if (SSL_client_hello_get0_ext(s, 0, &data, &data_size) != 1) {
  std::cout << "Warning: Error on SSL_client_hello_get0_ext: servername not available. Using dummy ctx." << std::endl;
  return ServerNameError(s, ctx_map);
 }

 // SNI Server Name, See https://tools.ietf.org/html/rfc6066 (TODO: why are there 5 bytes header?)
 std::string server_name {std::string((const char*)data, (size_t)data_size)};
 if (server_name.size() >= 5 && server_name[0] == '\0')
  server_name = server_name.substr(5);

 server_name = unbracketed(server_name);

 auto it {ctx_map.find(server_name)};
 std::shared_ptr<ssl::context> ctx{};
 if (it != ctx_map.end()) {
  ctx = it->second;
 } else {
  std::cout << "Warning: server_name " << server_name << " (" << server_name.size() << ") not found in list of prepared contexts. Using dummy ctx." << std::endl;
  return ServerNameError(s, ctx_map);
 }

 SSL_set_SSL_CTX(s, ctx->native_handle());
 
 return SSL_CLIENT_HELLO_SUCCESS;
}

} // anonymous namespace
//------------------------------------------------------------------------------

namespace HTTPS {

Server::Server(Config& config, boost::asio::io_context& ioc, const Socket& socket, plugins_container_type& plugins, Statistics& statistics)
 : ::Server(config, ioc, socket, plugins, statistics)
{
 load_certificates(); // load initially
}

Server::~Server()
{
}

void Server::load_certificates()
{
 // initial dummy, before we can add specific ctx w/ certificate
 std::shared_ptr<ssl::context> ctx_dummy{std::make_shared<ssl::context>(tls_method)};
 load_server_certificate(*ctx_dummy, "", "");
 SSL_CTX_set_client_hello_cb(ctx_dummy->native_handle(), servername_callback, &m_ctx);
 m_ctx.emplace("", ctx_dummy);

 // import the real certificates
 for (const auto& serve_site: m_socket.serve_sites) {
  for (const auto& site: m_config.Sites()) {
   if (site.first == serve_site) {
    std::shared_ptr<ssl::context> ctx {std::make_shared<ssl::context>(tls_method)};

    std::cout << "Creating SSL context/cert for site " << serve_site << " on port " << m_socket.port << std::endl;

    load_server_certificate(*ctx, site.second.cert_path, site.second.key_path);
    SSL_CTX_set_client_hello_cb(ctx->native_handle(), servername_callback, &m_ctx);

    for (const auto& host: site.second.hosts) {
     std::cout << "  Adding Host " << host << std::endl;
     m_ctx.emplace(unbracketed(host), ctx);
    }
   }
  }
 }
}

int Server::start()
{
 auto const address = net::ip::make_address(m_socket.address);
 auto const port = static_cast<unsigned short>(std::atoi(m_socket.port.data()));

 // Create and launch a listening port
 std::make_shared<listener>(
     m_ioc,
     *m_ctx[""],
     tcp::endpoint{address, port},
     *this)->run();

 return EXIT_SUCCESS;
}

} // namespace HTTPS