1 /** @file
2 * @brief GATT Current Time Service
3 */
4
5 /*
6 * Copyright (c) 2024 Croxel Inc.
7 *
8 * SPDX-License-Identifier: Apache-2.0
9 */
10
11 #undef _POSIX_C_SOURCE
12 #define _POSIX_C_SOURCE 200809L /* To get gmtime_r()'s prototype */
13
14 #ifdef CONFIG_BT_CTS_HELPER_API
15 #include <time.h>
16 #include <zephyr/sys/timeutil.h>
17 #endif
18
19 #include <stdbool.h>
20 #include <zephyr/sys/byteorder.h>
21
22 #include <zephyr/bluetooth/conn.h>
23 #include <zephyr/bluetooth/gatt.h>
24 #include <zephyr/bluetooth/uuid.h>
25 #include <zephyr/bluetooth/services/cts.h>
26
27 #include <zephyr/logging/log.h>
28 LOG_MODULE_REGISTER(cts, CONFIG_BT_CTS_LOG_LEVEL);
29
30 #define BT_CTS_ATT_ERR_VALUES_IGNORED 0x80
31 #define BT_CTS_FRACTION_256_MAX_VALUE 255
32
33 static const struct bt_cts_cb *cts_cb;
34
35 #ifdef CONFIG_BT_CTS_HELPER_API
36
bt_cts_time_to_unix_ms(const struct bt_cts_time_format * ct_time,int64_t * unix_ms)37 int bt_cts_time_to_unix_ms(const struct bt_cts_time_format *ct_time, int64_t *unix_ms)
38 {
39 struct tm date_time;
40 /* fill date time structure */
41 date_time.tm_year = sys_le16_to_cpu(ct_time->year); /* year (little endian) */
42 date_time.tm_year -= TIME_UTILS_BASE_YEAR;
43 date_time.tm_mon = ct_time->mon - 1; /* month start from 1, but need from 0 */
44 date_time.tm_mday = ct_time->mday; /* day of month */
45 date_time.tm_hour = ct_time->hours; /* hours of day */
46 date_time.tm_min = ct_time->min; /* minute of hour */
47 date_time.tm_sec = ct_time->sec; /* seconds of minute */
48 date_time.tm_wday = ct_time->wday % 7; /* for sundays convert to 0, else keep same */
49
50 LOG_DBG("CTS Write Time: %d/%d/%d %d:%d:%d", date_time.tm_year, date_time.tm_mon,
51 date_time.tm_mday, date_time.tm_hour, date_time.tm_min, date_time.tm_sec);
52 /* get unit timestamp from datetime */
53 (*unix_ms) = timeutil_timegm64(&date_time);
54 if ((*unix_ms) == ((time_t)-1)) {
55 return -EOVERFLOW;
56 }
57 LOG_DBG("CTS Write Unix: %lld", (*unix_ms));
58 (*unix_ms) *= MSEC_PER_SEC;
59 /* add fraction 256 part*/
60 (*unix_ms) += ((ct_time->fractions256 * MSEC_PER_SEC) / BT_CTS_FRACTION_256_MAX_VALUE);
61
62 return 0;
63 }
64
bt_cts_time_from_unix_ms(struct bt_cts_time_format * ct_time,int64_t unix_ms)65 int bt_cts_time_from_unix_ms(struct bt_cts_time_format *ct_time, int64_t unix_ms)
66 {
67 struct tm date_time;
68 time_t unix_ts = unix_ms / MSEC_PER_SEC;
69
70 /* 'Fractions 256 part of 'Exact Time 256' */
71 unix_ms %= MSEC_PER_SEC;
72 unix_ms *= BT_CTS_FRACTION_256_MAX_VALUE;
73 unix_ms /= MSEC_PER_SEC;
74 ct_time->fractions256 = unix_ms;
75
76 /* convert unix_ts to */
77 LOG_DBG("CTS Read Unix: %lld", unix_ts);
78 /* generate date time from unix timestamp */
79 if (gmtime_r(&unix_ts, &date_time) == NULL) {
80 return -EOVERFLOW;
81 }
82 date_time.tm_year += TIME_UTILS_BASE_YEAR;
83
84 LOG_DBG("CTS Read Time: %d/%d/%d %d:%d:%d", date_time.tm_year, date_time.tm_mon,
85 date_time.tm_mday, date_time.tm_hour, date_time.tm_min, date_time.tm_sec);
86
87 /* 'Exact Time 256' contains 'Day Date Time' which contains
88 * 'Date Time' - characteristic contains fields for:
89 * year, month, day, hours, minutes and seconds.
90 */
91 ct_time->year = sys_cpu_to_le16(date_time.tm_year);
92 ct_time->mon = date_time.tm_mon + 1; /* months starting from 1 */
93 ct_time->mday = date_time.tm_mday; /* Day of month */
94 ct_time->hours = date_time.tm_hour; /* hours */
95 ct_time->min = date_time.tm_min; /* minutes */
96 ct_time->sec = date_time.tm_sec; /* seconds */
97 /* day of week starting from 1-monday, 7-sunday */
98 ct_time->wday = date_time.tm_wday;
99 if (ct_time->wday == 0) {
100 ct_time->wday = 7; /* sunday is represented as 7 */
101 }
102 return 0;
103 }
104
105 #endif /* CONFIG_BT_CTS_HELPER_API */
106
ct_ccc_cfg_changed(const struct bt_gatt_attr * attr,uint16_t value)107 static void ct_ccc_cfg_changed(const struct bt_gatt_attr *attr, uint16_t value)
108 {
109 bool notif_enabled = (value == BT_GATT_CCC_NOTIFY);
110
111 LOG_INF("CTS Notifications %s", notif_enabled ? "enabled" : "disabled");
112
113 if (cts_cb->notification_changed) {
114 cts_cb->notification_changed(notif_enabled);
115 }
116 }
117
read_ct(struct bt_conn * conn,const struct bt_gatt_attr * attr,void * buf,uint16_t len,uint16_t offset)118 static ssize_t read_ct(struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf,
119 uint16_t len, uint16_t offset)
120 {
121 int err;
122 struct bt_cts_time_format ct_time;
123
124 err = cts_cb->fill_current_cts_time(&ct_time);
125 ct_time.reason = BT_CTS_UPDATE_REASON_UNKNOWN;
126
127 if (!err) {
128 return bt_gatt_attr_read(conn, attr, buf, len, offset, &ct_time, sizeof(ct_time));
129 } else {
130 return BT_GATT_ERR(BT_ATT_ERR_OUT_OF_RANGE);
131 }
132 }
133
write_ct(struct bt_conn * conn,const struct bt_gatt_attr * attr,const void * buf,uint16_t len,uint16_t offset,uint8_t flags)134 static ssize_t write_ct(struct bt_conn *conn, const struct bt_gatt_attr *attr, const void *buf,
135 uint16_t len, uint16_t offset, uint8_t flags)
136 {
137 int err;
138 struct bt_cts_time_format ct_time;
139
140 if (cts_cb->cts_time_write == NULL) {
141 return BT_GATT_ERR(BT_ATT_ERR_INSUFFICIENT_RESOURCES);
142 }
143
144 if ((offset != 0) || (offset + len != sizeof(ct_time))) {
145 return BT_GATT_ERR(BT_ATT_ERR_INVALID_OFFSET);
146 }
147
148 memcpy(&ct_time, buf, sizeof(ct_time));
149 err = cts_cb->cts_time_write(&ct_time);
150 if (err) {
151 return BT_GATT_ERR(BT_CTS_ATT_ERR_VALUES_IGNORED);
152 }
153
154 err = bt_cts_send_notification(BT_CTS_UPDATE_REASON_MANUAL);
155 if (err) {
156 return BT_GATT_ERR(BT_ATT_ERR_UNLIKELY);
157 }
158
159 return len;
160 }
161
162 /* Current Time Service Declaration */
163 BT_GATT_SERVICE_DEFINE(cts_svc, BT_GATT_PRIMARY_SERVICE(BT_UUID_CTS),
164 BT_GATT_CHARACTERISTIC(BT_UUID_CTS_CURRENT_TIME,
165 BT_GATT_CHRC_READ | BT_GATT_CHRC_WRITE |
166 BT_GATT_CHRC_NOTIFY,
167 BT_GATT_PERM_READ | BT_GATT_PERM_WRITE, read_ct,
168 write_ct, NULL),
169 BT_GATT_CCC(ct_ccc_cfg_changed, BT_GATT_PERM_READ | BT_GATT_PERM_WRITE));
170
bt_cts_init(const struct bt_cts_cb * cb)171 int bt_cts_init(const struct bt_cts_cb *cb)
172 {
173 __ASSERT(cb == NULL, "Current Time service need valid `struct bt_cts_cb` callback");
174 __ASSERT(cb->fill_current_cts_time == NULL,
175 "`fill_current_cts_time` callback api is required for functioning of CTS");
176 if (!cb || !cb->fill_current_cts_time) {
177 return -EINVAL;
178 }
179 cts_cb = cb;
180 return 0;
181 }
182
bt_cts_send_notification(enum bt_cts_update_reason reason)183 int bt_cts_send_notification(enum bt_cts_update_reason reason)
184 {
185 int err;
186 struct bt_cts_time_format ct_time;
187
188 err = cts_cb->fill_current_cts_time(&ct_time);
189 ct_time.reason = reason;
190 if (err) {
191 return err;
192 }
193 return bt_gatt_notify(NULL, &cts_svc.attrs[1], &ct_time, sizeof(ct_time));
194 }
195
