1 /*
2 * Copyright 2023-2024 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <openssl/macros.h>
11 #include "quic_local.h"
12 #include "internal/time.h"
13 #include "internal/thread.h"
14 #include "internal/thread_arch.h"
15 #include "internal/quic_thread_assist.h"
16
17 #if !defined(OPENSSL_NO_QUIC_THREAD_ASSIST)
18
19 /* Main loop for the QUIC assist thread. */
assist_thread_main(void * arg)20 static unsigned int assist_thread_main(void *arg)
21 {
22 QUIC_THREAD_ASSIST *qta = arg;
23 CRYPTO_MUTEX *m = ossl_quic_channel_get_mutex(qta->ch);
24 QUIC_REACTOR *rtor;
25
26 ossl_crypto_mutex_lock(m);
27
28 rtor = ossl_quic_channel_get_reactor(qta->ch);
29
30 for (;;) {
31 OSSL_TIME deadline;
32
33 if (qta->teardown)
34 break;
35
36 deadline = ossl_quic_reactor_get_tick_deadline(rtor);
37 if (qta->now_cb != NULL
38 && !ossl_time_is_zero(deadline)
39 && !ossl_time_is_infinite(deadline)) {
40 /*
41 * ossl_crypto_condvar_wait_timeout needs to use real time for the
42 * deadline
43 */
44 deadline = ossl_time_add(ossl_time_subtract(deadline,
45 qta->now_cb(qta->now_cb_arg)),
46 ossl_time_now());
47 }
48 ossl_crypto_condvar_wait_timeout(qta->cv, m, deadline);
49
50 /*
51 * We have now been woken up. This can be for one of the following
52 * reasons:
53 *
54 * - We have been asked to teardown (qta->teardown is set);
55 * - The tick deadline has passed.
56 * - The tick deadline has changed.
57 *
58 * For robustness, this loop also handles spurious wakeups correctly
59 * (which does not require any extra code).
60 */
61 if (qta->teardown)
62 break;
63
64 ossl_quic_reactor_tick(rtor, QUIC_REACTOR_TICK_FLAG_CHANNEL_ONLY);
65 }
66
67 ossl_crypto_mutex_unlock(m);
68 return 1;
69 }
70
ossl_quic_thread_assist_init_start(QUIC_THREAD_ASSIST * qta,QUIC_CHANNEL * ch,OSSL_TIME (* now_cb)(void * arg),void * now_cb_arg)71 int ossl_quic_thread_assist_init_start(QUIC_THREAD_ASSIST *qta,
72 QUIC_CHANNEL *ch,
73 OSSL_TIME (*now_cb)(void *arg),
74 void *now_cb_arg)
75 {
76 CRYPTO_MUTEX *mutex = ossl_quic_channel_get_mutex(ch);
77
78 if (mutex == NULL)
79 return 0;
80
81 qta->ch = ch;
82 qta->teardown = 0;
83 qta->joined = 0;
84 qta->now_cb = now_cb;
85 qta->now_cb_arg = now_cb_arg;
86
87 qta->cv = ossl_crypto_condvar_new();
88 if (qta->cv == NULL)
89 return 0;
90
91 qta->t = ossl_crypto_thread_native_start(assist_thread_main,
92 qta, /*joinable=*/1);
93 if (qta->t == NULL) {
94 ossl_crypto_condvar_free(&qta->cv);
95 return 0;
96 }
97
98 return 1;
99 }
100
ossl_quic_thread_assist_stop_async(QUIC_THREAD_ASSIST * qta)101 int ossl_quic_thread_assist_stop_async(QUIC_THREAD_ASSIST *qta)
102 {
103 if (!qta->teardown) {
104 qta->teardown = 1;
105 ossl_crypto_condvar_signal(qta->cv);
106 }
107
108 return 1;
109 }
110
ossl_quic_thread_assist_wait_stopped(QUIC_THREAD_ASSIST * qta)111 int ossl_quic_thread_assist_wait_stopped(QUIC_THREAD_ASSIST *qta)
112 {
113 CRYPTO_THREAD_RETVAL rv;
114 CRYPTO_MUTEX *m = ossl_quic_channel_get_mutex(qta->ch);
115
116 if (qta->joined)
117 return 1;
118
119 if (!ossl_quic_thread_assist_stop_async(qta))
120 return 0;
121
122 ossl_crypto_mutex_unlock(m);
123
124 if (!ossl_crypto_thread_native_join(qta->t, &rv)) {
125 ossl_crypto_mutex_lock(m);
126 return 0;
127 }
128
129 qta->joined = 1;
130
131 ossl_crypto_mutex_lock(m);
132 return 1;
133 }
134
ossl_quic_thread_assist_cleanup(QUIC_THREAD_ASSIST * qta)135 int ossl_quic_thread_assist_cleanup(QUIC_THREAD_ASSIST *qta)
136 {
137 if (!ossl_assert(qta->joined))
138 return 0;
139
140 ossl_crypto_condvar_free(&qta->cv);
141 ossl_crypto_thread_native_clean(qta->t);
142
143 qta->ch = NULL;
144 qta->t = NULL;
145 return 1;
146 }
147
ossl_quic_thread_assist_notify_deadline_changed(QUIC_THREAD_ASSIST * qta)148 int ossl_quic_thread_assist_notify_deadline_changed(QUIC_THREAD_ASSIST *qta)
149 {
150 if (qta->teardown)
151 return 0;
152
153 ossl_crypto_condvar_signal(qta->cv);
154 return 1;
155 }
156
157 #endif
158
