gsm23003: add osmo_imei_str_valid()
Verify 14 digit and 15 digit IMEI strings. OsmoHLR will use the 14
digit version to check IMEIs before writing them to the DB.
Place the Luhn checksum code in a dedicated osmo_luhn() function, so
it can be used elsewhere.
Related: OS#2541
Change-Id: Id2d2a3a93b033bafc74c62e15297034bf4aafe61
diff --git a/include/osmocom/gsm/gsm23003.h b/include/osmocom/gsm/gsm23003.h
index 2f380ae..b5c8dcd 100644
--- a/include/osmocom/gsm/gsm23003.h
+++ b/include/osmocom/gsm/gsm23003.h
@@ -93,6 +93,7 @@
bool osmo_imsi_str_valid(const char *imsi);
bool osmo_msisdn_str_valid(const char *msisdn);
+bool osmo_imei_str_valid(const char *imei, bool with_15th_digit);
const char *osmo_mcc_name(uint16_t mcc);
const char *osmo_mnc_name(uint16_t mnc, bool mnc_3_digits);