gprs: Add GPRS timer conversion functions
Currently, all GPRS timer values are hard-coded. To make these values
configurable in seconds and to show them, conversion functions from
and to seconds are needed.
This patch adds gprs_tmr_to_secs and gprs_secs_to_tmr_floor. Due to
the limited number of bits used to encode GPRS timer values, only a
few durations can be represented. gprs_secs_to_tmr_floor therefore
always returns the timer value that represents either the exact
number (if an exact representation exists) or the next lower number
for that an exact representation exists.
Sponsored-by: On-Waves ehf
diff --git a/openbsc/include/openbsc/gprs_utils.h b/openbsc/include/openbsc/gprs_utils.h
index 60b55a1..6880e05 100644
--- a/openbsc/include/openbsc/gprs_utils.h
+++ b/openbsc/include/openbsc/gprs_utils.h
@@ -31,6 +31,11 @@
size_t old_size, size_t new_size);
char *gprs_apn_to_str(char *out_str, const uint8_t *apn_enc, size_t rest_chars);
int gprs_str_to_apn(uint8_t *apn_enc, size_t max_len, const char *str);
+
+/* GSM 04.08, 10.5.7.3 GPRS Timer */
+int gprs_tmr_to_secs(uint8_t tmr);
+uint8_t gprs_secs_to_tmr_floor(int secs);
+
int gprs_is_mi_tmsi(const uint8_t *value, size_t value_len);
int gprs_is_mi_imsi(const uint8_t *value, size_t value_len);
int gprs_parse_mi_tmsi(const uint8_t *value, size_t value_len, uint32_t *tmsi);