cddl-cat
is a library for validating encoded data against a CDDL
document that describes the expected structure of the data.
Note: This library is fairly new, and may still contain significant bugs, ommissions, or unstable interfaces.
CDDL is a text document described by RFC8610 that describes data structures. CDDL is not tied to any specific serialization or encoding method; it can be used to validate data that is in CBOR or JSON format.
The goal of this library is to make CBOR or JSON data easy to validate against a CDDL schema description.
cddl-cat
supports Rust 1.37 and later.
Implementation Details
-
Supports CBOR and JSON encodings, controlled by the
serde_cbor
andserde_json
features. -
An "Intermediate Validation Tree" (IVT) is constructed from the CDDL AST; this removes some of the CDDL syntax detail resulting in a simplified tree that can be more easily validated. The IVT is constructed almost entirely of
Node
elements, allowing recursive validation. -
Validation is performed by first translating the incoming data into a generic form, so most of the validation code is completely agnostic to the serialization format.
-
Validation code uses a
Context
object to perform all rule lookups. This will allow stacking CDDL documents or building CDDL libraries that can be used by other CDDL schemas. In the future the validation process itself may be customized by changing theContext
configuration.
Examples
This example validates JSON-encoded data against a CDDL schema:
#
use validate_json_str;
let cddl_input = "person = {name: tstr, age: int}";
let json_str = r#"{ "name": "Bob", "age": 43 }"#;
#
validate_json_str.unwrap;
If the JSON data doesn't have the expected structure, an error will result:
#
use validate_json_str;
let cddl_input = "person = {name: tstr, age: int}";
let json_str = r#"{ "name": "Bob", "age": "forty three" }"#;
#
assert!;
A similar example, verifying CBOR-encoded data against a CDDL schema:
#
use validate_cbor_bytes;
use Serialize;
let input = PersonStruct ;
#
let cbor_bytes = to_vec.unwrap;
let cddl_input = "person = {name: tstr, age: int}";
#
validate_cbor_bytes.unwrap;
Supported prelude types:
any
,uint
,nint
,int
,bstr
,bytes
,tstr
,text
float
,float16
,float32
,float64
,float16-32
,float32-64
Note: float sizes are not validated.
Supported CDDL features:
- Basic prelude types (integers, floats, bool, nil, text strings, byte strings)
- Literal int, float, bool, UTF-8 text strings
- Byte strings in UTF-8 or hex
- Arrays and maps
- Rule lookups by name
- Groups
- Choices (using
/
or//
syntax) - Occurrences (
?
,*
,+
, orm*n
) - Ranges (e.g.
1..7
or1...8
) - Unwrapping (
~
) - Map keys with cut syntax (
^ =>
)
Unimplemented features:
- Generics
- Extend type with
/=
- Extend group with
//=
- Type sockets with
$
- Group sockets with
$$
- Control operators, e.g.
.size
,.bits
, ... - Group enumeration with
&
- Tagged data with
#
- Literal integers with
0x
or0b
- Hexfloat
- Base64 bytestring literals (
b64'...'
) - Prelude types that invoke CBOR tags (e.g.
tdate
orbiguint
)