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/core/utils.h b/include/osmocom/core/utils.h
index 04f2fb4..987080e 100644
--- a/include/osmocom/core/utils.h
+++ b/include/osmocom/core/utils.h
@@ -140,4 +140,6 @@
uint32_t osmo_isqrt32(uint32_t x);
+const char osmo_luhn(const char* in, int in_len);
+
/*! @} */