from oid.c:122
#define FN_OID_GET_OID_BY_ATTR1(FN_NAME, TYPE_T, LIST, ATTR1_TYPE, ATTR1) \
int FN_NAME( ATTR1_TYPE ATTR1, const char **oid, size_t *olen ) \
{ \
const TYPE_T *cur = (LIST); \
while( cur->descriptor.asn1 != NULL ) { \
if( cur->ATTR1 == (ATTR1) ) { \
*oid = cur->descriptor.asn1; \
*olen = cur->descriptor.asn1_len; \
return( 0 ); \
} \
cur++; \
} \
return( MBEDTLS_ERR_OID_NOT_FOUND ); \
}