summaryrefslogtreecommitdiffstats
path: root/src/quic_tp.c
blob: caf48ceb94621bfa1a5be1c23a349f591a2f017c (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
706
707
708
709
710
711
712
713
714
#include <arpa/inet.h>
#include <string.h>

#include <haproxy/global.h>
#include <haproxy/ncbuf-t.h>
#include <haproxy/net_helper.h>
#include <haproxy/quic_conn.h>
#include <haproxy/quic_enc.h>
#include <haproxy/quic_tp.h>
#include <haproxy/quic_trace.h>
#include <haproxy/trace.h>

#define QUIC_MAX_UDP_PAYLOAD_SIZE     2048

/* This is the values of some QUIC transport parameters when absent.
 * Should be used to initialize any transport parameters (local or remote)
 * before updating them with customized values.
 */
struct quic_transport_params quic_dflt_transport_params = {
	.max_udp_payload_size = QUIC_TP_DFLT_MAX_UDP_PAYLOAD_SIZE,
	.ack_delay_exponent   = QUIC_TP_DFLT_ACK_DELAY_COMPONENT,
	.max_ack_delay        = QUIC_TP_DFLT_MAX_ACK_DELAY,
	.active_connection_id_limit = QUIC_TP_DFLT_ACTIVE_CONNECTION_ID_LIMIT,
};

/* Initialize <dst> transport parameters with default values (when absent)
 * from <quic_dflt_transport_params>.
 * Never fails.
 */
static void quic_dflt_transport_params_cpy(struct quic_transport_params *dst)
{
	dst->max_udp_payload_size = quic_dflt_transport_params.max_udp_payload_size;
	dst->ack_delay_exponent   = quic_dflt_transport_params.ack_delay_exponent;
	dst->max_ack_delay        = quic_dflt_transport_params.max_ack_delay;
	dst->active_connection_id_limit = quic_dflt_transport_params.active_connection_id_limit;
}

/* Initialize <p> transport parameters. <server> is a boolean, set if TPs are
 * used by a server (haproxy frontend) else this is for a client (haproxy
 * backend).
 *
 * This must only be used for haproxy local parameters. To initialize peer
 * parameters, see quic_dflt_transport_params_cpy().
 *
 * Never fails.
 */
void quic_transport_params_init(struct quic_transport_params *p, int server)
{
	const uint64_t ncb_size = global.tune.bufsize - NCB_RESERVED_SZ;
	const int max_streams_bidi = global.tune.quic_frontend_max_streams_bidi;
	const int max_streams_uni = 3;

	/* Set RFC default values for unspecified parameters. */
	quic_dflt_transport_params_cpy(p);

	/* Set the max_udp_payload_size value. If not would equal to
	 * QUIC_TP_DFLT_MAX_UDP_PAYLOAD_SIZE
	 */
	p->max_udp_payload_size = QUIC_MAX_UDP_PAYLOAD_SIZE;
	if (server)
		p->max_idle_timeout = global.tune.quic_frontend_max_idle_timeout;
	else
		p->max_idle_timeout = global.tune.quic_backend_max_idle_timeout;

	p->initial_max_streams_bidi            = max_streams_bidi;
	p->initial_max_streams_uni             = max_streams_uni;
	p->initial_max_stream_data_bidi_local  = ncb_size;
	p->initial_max_stream_data_bidi_remote = ncb_size;
	p->initial_max_stream_data_uni         = ncb_size;
	p->initial_max_data = (max_streams_bidi + max_streams_uni) * ncb_size;

	if (server) {
		p->with_stateless_reset_token  = 1;
		p->disable_active_migration    = 1;
	}

	p->active_connection_id_limit          = 8;

	p->retry_source_connection_id.len = 0;
}

/* Encode <addr> preferred address transport parameter in <buf> without its
 * "type+len" prefix.
 * It is the responsibility of the caller to check there is enough room in <buf> to encode
 * this address.
 * Never fails.
 */
static void quic_transport_param_enc_pref_addr_val(unsigned char **buf,
                                                   const unsigned char *end,
                                                   struct tp_preferred_address *addr)
{
	write_n16(*buf, addr->ipv4_port);
	*buf += sizeof addr->ipv4_port;

	memcpy(*buf, (uint8_t *)&addr->ipv4_addr.s_addr, sizeof(addr->ipv4_addr.s_addr));
	*buf += sizeof(addr->ipv4_addr.s_addr);

	write_n16(*buf, addr->ipv6_port);
	*buf += sizeof addr->ipv6_port;

	memcpy(*buf, addr->ipv6_addr.s6_addr, sizeof(addr->ipv6_addr.s6_addr));
	*buf += sizeof(addr->ipv6_addr.s6_addr);

	*(*buf)++ = addr->cid.len;
	if (addr->cid.len) {
		memcpy(*buf, addr->cid.data, addr->cid.len);
		*buf += addr->cid.len;
	}

	memcpy(*buf, addr->stateless_reset_token, sizeof addr->stateless_reset_token);
	*buf += sizeof addr->stateless_reset_token;
}

/* Decode into <addr> preferred address transport parameter found in <*buf> buffer.
 * Returns 1 if succeeded, 0 if not.
 */
static int quic_transport_param_dec_pref_addr(struct tp_preferred_address *addr,
                                              const unsigned char **buf,
                                              const unsigned char *end)
{
	ssize_t addr_len;

	addr_len = sizeof(addr->ipv4_port) + sizeof(addr->ipv4_addr.s_addr);
	addr_len += sizeof(addr->ipv6_port) + sizeof(addr->ipv6_addr.s6_addr);
	addr_len += sizeof(addr->cid.len);

	if (end - *buf < addr_len)
		return 0;

	memcpy((uint8_t *)&addr->ipv4_addr.s_addr, *buf, sizeof(addr->ipv4_addr.s_addr));
	*buf += sizeof(addr->ipv4_addr.s_addr);

	addr->ipv4_port = read_n16(*buf);
	*buf += sizeof addr->ipv4_port;

	memcpy(addr->ipv6_addr.s6_addr, *buf, sizeof(addr->ipv6_addr.s6_addr));
	*buf += sizeof(addr->ipv6_addr.s6_addr);

	addr->ipv6_port = read_n16(*buf);
	*buf += sizeof addr->ipv6_port;

	addr->cid.len = *(*buf)++;
	if (addr->cid.len) {
		if (end - sizeof(addr->stateless_reset_token) - *buf > addr->cid.len ||
		    addr->cid.len > sizeof(addr->cid.data)) {
			return 0;
		}

		memcpy(addr->cid.data, *buf, addr->cid.len);
		*buf += addr->cid.len;
	}

	if (end - *buf != sizeof(addr->stateless_reset_token))
		return 0;

	memcpy(addr->stateless_reset_token, *buf, end - *buf);
	*buf += sizeof addr->stateless_reset_token;

	return *buf == end;
}

/* Decode into <v> version information received transport parameters from <*buf>
 * buffer. <server> must be set to 1 for QUIC clients which receive server
 * transport parameters, and 0 for QUIC servers which receive client transport
 * parameters.
 * Also set the QUIC negotiated version into <tp>.
 * Return 1 if succeeded, 0 if not.
 */
static int quic_transport_param_dec_version_info(struct tp_version_information *tp,
                                                 const unsigned char **buf,
                                                 const unsigned char *end, int server)
{
	size_t tp_len = end - *buf;
	const uint32_t *ver, *others;

	/* <tp_len> must be a multiple of sizeof(uint32_t) */
	if (tp_len < sizeof tp->chosen || (tp_len & 0x3))
		return 0;

	tp->chosen = ntohl(*(uint32_t *)*buf);
	/* Must not be null */
	if (!tp->chosen)
		return 0;

	*buf += sizeof tp->chosen;
	others = (const uint32_t *)*buf;

	/* Others versions must not be null */
	for (ver = others; ver < (const uint32_t *)end; ver++) {
		if (!*ver)
			return 0;
	}

	if (server)
		/* TODO: not supported */
		return 0;

	for (ver = others; ver < (const uint32_t *)end; ver++) {
		if (!tp->negotiated_version) {
			int i;

			for (i = 0; i < quic_versions_nb; i++) {
				if (ntohl(*ver) == quic_versions[i].num) {
					tp->negotiated_version = &quic_versions[i];
					break;
				}
			}
		}

		if (preferred_version && ntohl(*ver) == preferred_version->num) {
			tp->negotiated_version = preferred_version;
			goto out;
		}
	}

 out:
	*buf = end;

	return 1;
}

/* Decode into <p> struct a transport parameter found in <*buf> buffer with
 * <type> as type and <len> as length, depending on <server> boolean value which
 * must be set to 1 for a server (haproxy listener) or 0 for a client (connection
 * to an haproxy server).
 */
static int quic_transport_param_decode(struct quic_transport_params *p,
                                       int server, uint64_t type,
                                       const unsigned char **buf, size_t len)
{
	const unsigned char *end = *buf + len;

	switch (type) {
	case QUIC_TP_ORIGINAL_DESTINATION_CONNECTION_ID:
		if (!server || len > sizeof p->original_destination_connection_id.data)
			return 0;

		if (len)
			memcpy(p->original_destination_connection_id.data, *buf, len);
		p->original_destination_connection_id.len = len;
		*buf += len;
		p->original_destination_connection_id_present = 1;
		break;
	case QUIC_TP_INITIAL_SOURCE_CONNECTION_ID:
		if (len > sizeof p->initial_source_connection_id.data)
			return 0;

		if (len)
			memcpy(p->initial_source_connection_id.data, *buf, len);
		p->initial_source_connection_id.len = len;
		*buf += len;
		p->initial_source_connection_id_present = 1;
		break;
	case QUIC_TP_STATELESS_RESET_TOKEN:
		if (!server || len != sizeof p->stateless_reset_token)
			return 0;
		memcpy(p->stateless_reset_token, *buf, len);
		*buf += len;
		p->with_stateless_reset_token = 1;
		break;
	case QUIC_TP_PREFERRED_ADDRESS:
		if (!server)
			return 0;
		if (!quic_transport_param_dec_pref_addr(&p->preferred_address, buf, *buf + len))
			return 0;
		p->with_preferred_address = 1;
		break;
	case QUIC_TP_MAX_IDLE_TIMEOUT:
		if (!quic_dec_int(&p->max_idle_timeout, buf, end))
			return 0;
		break;
	case QUIC_TP_MAX_UDP_PAYLOAD_SIZE:
		if (!quic_dec_int(&p->max_udp_payload_size, buf, end))
			return 0;
		break;
	case QUIC_TP_INITIAL_MAX_DATA:
		if (!quic_dec_int(&p->initial_max_data, buf, end))
			return 0;
		break;
	case QUIC_TP_INITIAL_MAX_STREAM_DATA_BIDI_LOCAL:
		if (!quic_dec_int(&p->initial_max_stream_data_bidi_local, buf, end))
			return 0;
		break;
	case QUIC_TP_INITIAL_MAX_STREAM_DATA_BIDI_REMOTE:
		if (!quic_dec_int(&p->initial_max_stream_data_bidi_remote, buf, end))
			return 0;
		break;
	case QUIC_TP_INITIAL_MAX_STREAM_DATA_UNI:
		if (!quic_dec_int(&p->initial_max_stream_data_uni, buf, end))
			return 0;
		break;
	case QUIC_TP_INITIAL_MAX_STREAMS_BIDI:
		if (!quic_dec_int(&p->initial_max_streams_bidi, buf, end))
			return 0;
		break;
	case QUIC_TP_INITIAL_MAX_STREAMS_UNI:
		if (!quic_dec_int(&p->initial_max_streams_uni, buf, end))
			return 0;
		break;
	case QUIC_TP_ACK_DELAY_EXPONENT:
		if (!quic_dec_int(&p->ack_delay_exponent, buf, end) ||
			p->ack_delay_exponent > QUIC_TP_ACK_DELAY_EXPONENT_LIMIT)
			return 0;
		break;
	case QUIC_TP_MAX_ACK_DELAY:
		if (!quic_dec_int(&p->max_ack_delay, buf, end) ||
			p->max_ack_delay > QUIC_TP_MAX_ACK_DELAY_LIMIT)
			return 0;
		break;
	case QUIC_TP_DISABLE_ACTIVE_MIGRATION:
		/* Zero-length parameter type. */
		if (len != 0)
			return 0;
		p->disable_active_migration = 1;
		break;
	case QUIC_TP_ACTIVE_CONNECTION_ID_LIMIT:
		if (!quic_dec_int(&p->active_connection_id_limit, buf, end))
			return 0;
		break;
	case QUIC_TP_VERSION_INFORMATION:
		if (!quic_transport_param_dec_version_info(&p->version_information,
		                                           buf, *buf + len, server))
			return 0;
		break;
	default:
		*buf += len;
	};

	return *buf == end;
}

/* Encode <type> and <len> variable length values in <buf>.
 * Returns 1 if succeeded, 0 if not.
 */
static int quic_transport_param_encode_type_len(unsigned char **buf,
                                                const unsigned char *end,
                                                uint64_t type, uint64_t len)
{
	return quic_enc_int(buf, end, type) && quic_enc_int(buf, end, len);
}

/* Decode variable length type and length values of a QUIC transport parameter
 * into <type> and <len> found in <*buf> buffer.
 * Returns 1 if succeeded, 0 if not.
 */
static int quic_transport_param_decode_type_len(uint64_t *type, uint64_t *len,
                                                const unsigned char **buf,
                                                const unsigned char *end)
{
	return quic_dec_int(type, buf, end) && quic_dec_int(len, buf, end);
}

/* Encode <param> bytes stream with <type> as type and <length> as length into buf.
 * Returns 1 if succeeded, 0 if not.
 */
static int quic_transport_param_enc_mem(unsigned char **buf, const unsigned char *end,
                                        uint64_t type, void *param, uint64_t length)
{
	if (!quic_transport_param_encode_type_len(buf, end, type, length))
		return 0;

	if (end - *buf < length)
		return 0;

	if (length)
		memcpy(*buf, param, length);
	*buf += length;

	return 1;
}

/* Encode <val> 64-bits value as variable length integer into <buf>.
 * Returns 1 if succeeded, 0 if not.
 */
static int quic_transport_param_enc_int(unsigned char **buf,
                                        const unsigned char *end,
                                        uint64_t type, uint64_t val)
{
	size_t len;

	len = quic_int_getsize(val);

	return len && quic_transport_param_encode_type_len(buf, end, type, len) &&
		quic_enc_int(buf, end, val);
}

/* Returns the required length in bytes to encode <cid> QUIC connection ID. */
static inline size_t sizeof_quic_cid(const struct tp_cid *cid)
{
	return sizeof cid->len + cid->len;
}

/* Encode <addr> preferred address into <buf>.
 * Returns 1 if succeeded, 0 if not.
 */
static int quic_transport_param_enc_pref_addr(unsigned char **buf,
                                              const unsigned char *end,
                                              struct tp_preferred_address *addr)
{
	uint64_t addr_len = 0;

	addr_len += sizeof(addr->ipv4_port) + sizeof(addr->ipv4_addr.s_addr);
	addr_len += sizeof(addr->ipv6_port) + sizeof(addr->ipv6_addr.s6_addr);
	addr_len += sizeof_quic_cid(&addr->cid);
	addr_len += sizeof(addr->stateless_reset_token);

	if (!quic_transport_param_encode_type_len(buf, end, QUIC_TP_PREFERRED_ADDRESS, addr_len))
		return 0;

	if (end - *buf < addr_len)
		return 0;

	quic_transport_param_enc_pref_addr_val(buf, end, addr);

	return 1;
}

/* Encode version information transport parameters with <chosen_version> as chosen
 * version.
 * Return 1 if succeeded, 0 if not.
 */
static int quic_transport_param_enc_version_info(unsigned char **buf,
                                                 const unsigned char *end,
                                                 const struct quic_version *chosen_version,
                                                 int server)
{
	int i;
	uint64_t tp_len;
	uint32_t ver;

	tp_len = sizeof chosen_version->num + quic_versions_nb * sizeof(uint32_t);
	if (!quic_transport_param_encode_type_len(buf, end,
	                                          QUIC_TP_VERSION_INFORMATION,
	                                          tp_len))
		return 0;

	if (end - *buf < tp_len)
		return 0;

	/* First: chosen version */
	ver = htonl(chosen_version->num);
	memcpy(*buf, &ver, sizeof ver);
	*buf += sizeof ver;
	/* For servers: all supported version, chosen included */
	for (i = 0; i < quic_versions_nb; i++) {
		ver = htonl(quic_versions[i].num);
		memcpy(*buf, &ver, sizeof ver);
		*buf += sizeof ver;
	}

	return 1;
}

/* Encode <p> transport parameter into <buf> depending on <server> value which
 * must be set to 1 for a server (haproxy listener) or 0 for a client
 * (connection to a haproxy server).
 * Return the number of bytes consumed if succeeded, 0 if not.
 */
int quic_transport_params_encode(unsigned char *buf,
                                 const unsigned char *end,
                                 struct quic_transport_params *p,
                                 const struct quic_version *chosen_version,
                                 int server)
{
	unsigned char *head;
	unsigned char *pos;

	head = pos = buf;
	if (server) {
		if (!quic_transport_param_enc_mem(&pos, end,
		                                  QUIC_TP_ORIGINAL_DESTINATION_CONNECTION_ID,
		                                  p->original_destination_connection_id.data,
		                                  p->original_destination_connection_id.len))
			return 0;

		if (p->retry_source_connection_id.len) {
			if (!quic_transport_param_enc_mem(&pos, end,
			                                  QUIC_TP_RETRY_SOURCE_CONNECTION_ID,
			                                  p->retry_source_connection_id.data,
			                                  p->retry_source_connection_id.len))
				return 0;
		}

		if (p->with_stateless_reset_token &&
			!quic_transport_param_enc_mem(&pos, end, QUIC_TP_STATELESS_RESET_TOKEN,
			                              p->stateless_reset_token,
			                              sizeof p->stateless_reset_token))
			return 0;
		if (p->with_preferred_address &&
			!quic_transport_param_enc_pref_addr(&pos, end, &p->preferred_address))
			return 0;
	}

	if (!quic_transport_param_enc_mem(&pos, end,
	                                  QUIC_TP_INITIAL_SOURCE_CONNECTION_ID,
	                                  p->initial_source_connection_id.data,
	                                  p->initial_source_connection_id.len))
		return 0;

	if (p->max_idle_timeout &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_MAX_IDLE_TIMEOUT, p->max_idle_timeout))
		return 0;

	/*
	 * "max_packet_size" transport parameter must be transmitted only if different
	 * of the default value.
	 */
	if (p->max_udp_payload_size != QUIC_TP_DFLT_MAX_UDP_PAYLOAD_SIZE &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_MAX_UDP_PAYLOAD_SIZE, p->max_udp_payload_size))
		return 0;

	if (p->initial_max_data &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_INITIAL_MAX_DATA, p->initial_max_data))
	    return 0;

	if (p->initial_max_stream_data_bidi_local &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_INITIAL_MAX_STREAM_DATA_BIDI_LOCAL,
	                                          p->initial_max_stream_data_bidi_local))
	    return 0;

	if (p->initial_max_stream_data_bidi_remote &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_INITIAL_MAX_STREAM_DATA_BIDI_REMOTE,
	                                          p->initial_max_stream_data_bidi_remote))
	    return 0;

	if (p->initial_max_stream_data_uni &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_INITIAL_MAX_STREAM_DATA_UNI,
	                                          p->initial_max_stream_data_uni))
	    return 0;

	if (p->initial_max_streams_bidi &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_INITIAL_MAX_STREAMS_BIDI,
	                                          p->initial_max_streams_bidi))
	    return 0;

	if (p->initial_max_streams_uni &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_INITIAL_MAX_STREAMS_UNI,
	                                          p->initial_max_streams_uni))
	    return 0;

	/*
	 * "ack_delay_exponent" transport parameter must be transmitted only if different
	 * of the default value.
	 */
	if (p->ack_delay_exponent != QUIC_TP_DFLT_ACK_DELAY_COMPONENT  &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_ACK_DELAY_EXPONENT, p->ack_delay_exponent))
	    return 0;

	/*
	 * "max_ack_delay" transport parameter must be transmitted only if different
	 * of the default value.
	 */
	if (p->max_ack_delay != QUIC_TP_DFLT_MAX_ACK_DELAY &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_MAX_ACK_DELAY, p->max_ack_delay))
	    return 0;

	/* 0-length value */
	if (p->disable_active_migration &&
	    !quic_transport_param_encode_type_len(&pos, end, QUIC_TP_DISABLE_ACTIVE_MIGRATION, 0))
		return 0;

	if (p->active_connection_id_limit &&
	    p->active_connection_id_limit != QUIC_TP_DFLT_ACTIVE_CONNECTION_ID_LIMIT &&
	    !quic_transport_param_enc_int(&pos, end, QUIC_TP_ACTIVE_CONNECTION_ID_LIMIT,
	                                  p->active_connection_id_limit))
	    return 0;

	if (!quic_transport_param_enc_version_info(&pos, end, chosen_version, server))
		return 0;

	return pos - head;
}

/* Decode transport parameters found in <buf> buffer into <p>, depending on
 * <server> boolean value which must be set to 1 for a server (haproxy listener)
 * or 0 for a client (connection to a haproxy server).
 * Returns 1 if succeeded, 0 if not.
 */
static int quic_transport_params_decode(struct quic_transport_params *p, int server,
                                        const unsigned char *buf,
                                        const unsigned char *end)
{
	const unsigned char *pos;
	uint64_t type, len = 0;

	pos = buf;

	while (pos != end) {
		if (!quic_transport_param_decode_type_len(&type, &len, &pos, end))
			return 0;

		if (end - pos < len)
			return 0;

		if (!quic_transport_param_decode(p, server, type, &pos, len))
			return 0;
	}

	/*
	 * A server MUST send original_destination_connection_id transport parameter.
	 * initial_source_connection_id must be present both for server and client.
	 */
	if ((server && !p->original_destination_connection_id_present) ||
	    !p->initial_source_connection_id_present)
		return 0;

	/* Note that if not received by the peer, active_connection_id_limit will
	 * have QUIC_TP_DFLT_ACTIVE_CONNECTION_ID_LIMIT as default value. This
	 * is also the minimum value for this transport parameter.
	 */
	if (p->active_connection_id_limit < QUIC_TP_DFLT_ACTIVE_CONNECTION_ID_LIMIT)
		return 0;

	return 1;
}

/* Store transport parameters found in <buf> buffer into <qc> QUIC connection
 * depending on <server> value which must be 1 for a server (haproxy listener)
 * or 0 for a client (connection to a haproxy server).
 * Note that peer transport parameters are stored in the TX part of the connection:
 * they are used to send packets to the peer with its transport parameters as
 * limitations.
 * Returns 1 if succeeded, 0 if not.
 */
int quic_transport_params_store(struct quic_conn *qc, int server,
                                const unsigned char *buf,
                                const unsigned char *end)
{
	struct quic_transport_params *tx_params = &qc->tx.params;
	struct quic_transport_params *rx_params = &qc->rx.params;
	/* Initial source connection ID */
	struct tp_cid *iscid;

	/* initialize peer TPs to RFC default value */
	quic_dflt_transport_params_cpy(tx_params);

	if (!quic_transport_params_decode(tx_params, server, buf, end))
		return 0;

	/* Update the connection from transport parameters received */
	if (tx_params->version_information.negotiated_version &&
	    tx_params->version_information.negotiated_version != qc->original_version)
		qc->negotiated_version =
			qc->tx.params.version_information.negotiated_version;

	if (tx_params->max_ack_delay)
		qc->max_ack_delay = tx_params->max_ack_delay;

	if (tx_params->max_idle_timeout && rx_params->max_idle_timeout)
		qc->max_idle_timeout =
			QUIC_MIN(tx_params->max_idle_timeout, rx_params->max_idle_timeout);
	else
		qc->max_idle_timeout =
			QUIC_MAX(tx_params->max_idle_timeout, rx_params->max_idle_timeout);
	TRACE_PROTO("\nTX(remote) transp. params.", QUIC_EV_TRANSP_PARAMS, qc, tx_params);

	/* Check that the "initial_source_connection_id" transport parameter matches
	 * the SCID received which is also the DCID of the connection.
	 */
	iscid = &tx_params->initial_source_connection_id;
	if (qc->dcid.len != iscid->len ||
	    (qc->dcid.len && memcmp(qc->dcid.data, iscid->data, qc->dcid.len))) {
		TRACE_PROTO("initial_source_connection_id transport parameter mismatch",
		            QUIC_EV_TRANSP_PARAMS, qc);
		/* Kill the connection as soon as possible */
		qc_kill_conn(qc);
	}

	return 1;
}

/* QUIC server (or haproxy listener) only function.
 * Initialize the local transport parameters <rx_params> from <listener_params>
 * coming from configuration and Initial packet information (destination
 * connection ID, source connection ID, original destination connection ID) from
 * client token.
 * Returns 1 if succeeded, 0 if not.
 */
int qc_lstnr_params_init(struct quic_conn *qc,
                         const struct quic_transport_params *listener_params,
                         const unsigned char *stateless_reset_token,
                         const unsigned char *dcid, size_t dcidlen,
                         const unsigned char *scid, size_t scidlen,
                         const struct quic_cid *token_odcid)
{
	struct quic_transport_params *rx_params = &qc->rx.params;
	struct tp_cid *odcid_param = &rx_params->original_destination_connection_id;

	/* Copy the transport parameters. */
	*rx_params = *listener_params;
	/* Copy the stateless reset token */
	memcpy(rx_params->stateless_reset_token, stateless_reset_token,
	       sizeof rx_params->stateless_reset_token);
	/* Copy original_destination_connection_id transport parameter. */
	if (token_odcid->len) {
		memcpy(odcid_param->data, token_odcid->data, token_odcid->len);
		odcid_param->len = token_odcid->len;
		/* Copy retry_source_connection_id transport parameter. */
		memcpy(rx_params->retry_source_connection_id.data, dcid, dcidlen);
		rx_params->retry_source_connection_id.len = dcidlen;
	}
	else {
		memcpy(odcid_param->data, dcid, dcidlen);
		odcid_param->len = dcidlen;
	}

	/* Copy the initial source connection ID. */
	memcpy(rx_params->initial_source_connection_id.data, scid, scidlen);
	rx_params->initial_source_connection_id.len = scidlen;
	TRACE_PROTO("\nRX(local) transp. params.", QUIC_EV_TRANSP_PARAMS, qc, rx_params);

	return 1;
}