1 /**
2  * \file timing.h
3  *
4  * \brief Portable interface to timeouts and to the CPU cycle counter
5  */
6 /*
7  *  Copyright The Mbed TLS Contributors
8  *  SPDX-License-Identifier: Apache-2.0
9  *
10  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
11  *  not use this file except in compliance with the License.
12  *  You may obtain a copy of the License at
13  *
14  *  http://www.apache.org/licenses/LICENSE-2.0
15  *
16  *  Unless required by applicable law or agreed to in writing, software
17  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
18  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19  *  See the License for the specific language governing permissions and
20  *  limitations under the License.
21  */
22 #ifndef MBEDTLS_TIMING_H
23 #define MBEDTLS_TIMING_H
24 #include "mbedtls/private_access.h"
25 
26 #include "mbedtls/build_info.h"
27 
28 #include <stdint.h>
29 
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33 
34 #if !defined(MBEDTLS_TIMING_ALT)
35 // Regular implementation
36 //
37 
38 /**
39  * \brief          timer structure
40  */
41 struct mbedtls_timing_hr_time
42 {
43     unsigned char MBEDTLS_PRIVATE(opaque)[32];
44 };
45 
46 /**
47  * \brief          Context for mbedtls_timing_set/get_delay()
48  */
49 typedef struct mbedtls_timing_delay_context
50 {
51     struct mbedtls_timing_hr_time   MBEDTLS_PRIVATE(timer);
52     uint32_t                        MBEDTLS_PRIVATE(int_ms);
53     uint32_t                        MBEDTLS_PRIVATE(fin_ms);
54 } mbedtls_timing_delay_context;
55 
56 #else  /* MBEDTLS_TIMING_ALT */
57 #include "timing_alt.h"
58 #endif /* MBEDTLS_TIMING_ALT */
59 
60 /* Internal use */
61 unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset );
62 
63 /**
64  * \brief          Set a pair of delays to watch
65  *                 (See \c mbedtls_timing_get_delay().)
66  *
67  * \param data     Pointer to timing data.
68  *                 Must point to a valid \c mbedtls_timing_delay_context struct.
69  * \param int_ms   First (intermediate) delay in milliseconds.
70  *                 The effect if int_ms > fin_ms is unspecified.
71  * \param fin_ms   Second (final) delay in milliseconds.
72  *                 Pass 0 to cancel the current delay.
73  *
74  * \note           To set a single delay, either use \c mbedtls_timing_set_timer
75  *                 directly or use this function with int_ms == fin_ms.
76  */
77 void mbedtls_timing_set_delay( void *data, uint32_t int_ms, uint32_t fin_ms );
78 
79 /**
80  * \brief          Get the status of delays
81  *                 (Memory helper: number of delays passed.)
82  *
83  * \param data     Pointer to timing data
84  *                 Must point to a valid \c mbedtls_timing_delay_context struct.
85  *
86  * \return         -1 if cancelled (fin_ms = 0),
87  *                  0 if none of the delays are passed,
88  *                  1 if only the intermediate delay is passed,
89  *                  2 if the final delay is passed.
90  */
91 int mbedtls_timing_get_delay( void *data );
92 
93 #ifdef __cplusplus
94 }
95 #endif
96 
97 #endif /* timing.h */
98