asn1rs - ASN.1 Compiler for Rust

This crate generates Rust Code and optionally compatible Protobuf and SQL schema files from ASN.1 definitions. Basic support for serde integration is provided. The crate can be used as standalone CLI binary or used as library through its API (for example inside the build.rs script).

Support Table

| Feature | Parses | UPER | Protobuf | PSQL | Async PSQL | UPER Legacy | | --------------------|:--------|:--------|:------------|:------------|:-----------|------------------:| | SEQUENCE | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | | ...extensible | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | 🔶 not serialized | | SEQUENCE OF | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | | ...SIZE(A..B) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored️ | | ...SIZE(A..B,...) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored️ | | SET | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ⚠️ ignored️ | | ...extensible | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | 🔶 not serialized | | SET OF | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ⚠️ ignored️ | | ...SIZE(A..B) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored️ | | ...SIZE(A..B,...) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored️ | | ENUMERATED | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes |
| ...extensible | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | 🔶 not serialized |
| CHOICE | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes |
| ...extensible | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | 🔶 not serialized | | BIT STRING | ✔️ yes | ✔️ yes | ✔️ yes(1) | ✔️ yes(1) | ✔️ yes(1) | ✔️ yes | | ...SIZE(A..B) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored | | ...SIZE(A..B,...) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored | | OCTET STRING | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | | ...SIZE(A..B) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored | | ...SIZE(A..B,...) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored |
| UTF8String | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | | ...SIZE(A..B) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored | | ...SIZE(A..B,...) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ⚠️ ignored | | IA5String | ✔️ yes | ✔️ yes | ✔️ yes(1) | ✔️ yes(1) | ✔️ yes(1) | ❌ ub | | ...SIZE(A..B) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ❌ ub | | ...SIZE(A..B,...) | ✔️ yes | ✔️ yes | 🆗 ignored | 🆗 ignored | 🆗 ignored | ❌ ub |
| INTEGER | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | | ...A..B | ✔️ yes | ✔️ yes | ✔️ yes(2) | ✔️ yes(2) | ✔️ yes(2) | ✔️ yes | | ...A..B,... | ✔️ yes | ✔️ yes | ✔️ yes(2) | ✔️ yes(2) | ✔️ yes(2) | ⚠️ ignored | | BOOLEAN | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | | OPTIONAL | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | ✔️ yes | | IMPORTS..FROM..; | ✔️ yes | | | | | | | ObjectIdentifiers | ✔️ yes | | | | | |

• ✔️ yes: according to specification
• ✔️ yes(1): different representation
• ✔️ yes(2): as close as possible to the original specification (sometimes yes, sometimes yes(1))
• 🔶 not serialized: values are not serialized or deserialized in this case, might break compatibility
• ⚠️ ignored️: constraint is ignored, this most likely breaks compatibility
• 🆗 ignored: constraint is ignored but it does not break compatibility
• ❌ ub: undefined behavior - whatever seems reasonable to prevent compiler errors and somehow transmit the value
• 🟥 error: fails to compile / translate

Supported standards

• itu-t(0) identified-organization(4) etsi(0) itsDomain(5) wg1(1) ts(102894) cdd(2) version(1) (ITS-Container)
• itu-t(0) identified-organization(4) etsi(0) itsDomain(5) wg1(1) en(302637) cam(2) version(1) (CAM-PDU-Descriptions)

CLI usage

It is always helpful to check asn1rs --help in advance. The basic usage can be seen blow:

asn1rs -t rust directory/for/rust/files some.asn1 messages.asn1

asn1rs -t proto directory/for/protobuf/files some.asn1 messages.asn1

asn1rs -t sql directory/for/sql/schema/files some.asn1 messages.asn1

API usage

The following example generates Rust, Protobuf and SQL files for all .asn1-files in the asn/ directory of the project. While the generated Rust code is written to the src/ directory, the Protobuf files are written to proto/ and the SQL files are written to sql/. Additionally, in this example each generated Rust-Type also receives Serialize and Deserialize derive directives (#[derive(Serialize, Deserialize)]) for automatic serde integration.

Sample build.rs file:

```rust use asn1rs::converter::Converter; use asn1rs::gen::rust::RustCodeGenerator; use asn1rs::gen::sql::SqlDefGenerator;

pub fn main() { let mut converter = Converter::default();

// collecting all relevant .asn1 files
std::fs::read_dir("../protocol/asn")
    .into_iter()
    .flat_map(|read_dir| {
        read_dir
            .into_iter()
            .flat_map(|dir_entry| dir_entry.into_iter())
            .flat_map(|entry| {
                entry
                    .path()
                    .as_os_str()
                    .to_os_string()
                    .into_string()
                    .into_iter()
            })
            .filter(|entry| entry.ends_with(".asn1"))
    })
    .for_each(|path| {
        if let Err(e) = converter.load_file(&path) {
            println!("cargo:rerun-if-changed={}", path);
            panic!("Loading of .asn1 file failed {}: {:?}", path, e);
        }
    });

// writing the .rs files into src with serde_derive support
// feature flags decide whether additional code for protobuf and (async) psql is generated
if let Err(e) = converter.to_rust("src/", |generator: &mut RustCodeGenerator| {
    generator.add_global_derive("Serialize"); // Adds serde_derive support: #[derive(Serialize)]
    generator.add_global_derive("Deserialize"); // Adds serde_derive support: #[derive(Deserialize)]
}) {
    panic!("Conversion to rust failed: {:?}", e);
}

// OPTIONAL: writing the .proto representation to ../protocol/proto
if let Err(e) = converter.to_protobuf("../protocol/proto/") {
    panic!("Conversion to proto failed: {:?}", e);
}

// OPTIONAL: writing the .sql schema files to ../protocol/sql
if let Err(e) = converter.to_sql_with(
    "../protocol/sql/",
    SqlDefGenerator::default() // optional parameter, alternatively see Converter::to_sql(&self, &str)
        .optimize_tables_for_write_performance() // optional
        .wrap_primary_key_on_overflow(), // optional
) {
    panic!("Conversion to sql failed: {:?}", e);
}

}

```

Inlining ASN.1 with procedural macros

Minimal example by inlining the ASN.1 definition. For more examples, see tests/. ```rust use asn1rs::prelude::*;

asntorust!( r"BasicInteger DEFINITIONS AUTOMATIC TAGS ::= BEGIN

RangedMax ::= Integer (0..MAX)

NotRanged ::= Integer

END"

);

[test]

fn testwriteread() { // inner INTEGER identified as u64 let value = NotRanged(123_u64);

let mut writer = UperWriter::default();
writer.write(&value).expect("Failed to serialize");

let mut reader = writer.into_reader();
let value2 = reader.read::<NotRanged>().expect("Failed to deserialize");

assert_eq!(value, value2);

}

[test]

fn testconstrainteq() { // these types should normally not be accessed, but in this exampled they show // the way the ASN.1 constraints are encoded in to the struct type constraints. use asn1rs::syn::numbers::Constraint; asserteq!( asn1rsRangedMaxField0Constraint::MIN, _asn1rsNotRangedField0Constraint::MIN, ); asserteq!( asn1rsRangedMaxField0Constraint::MAX, _asn1rsNotRangedField0Constraint::MAX, ); } ```

Example ASN.1-Definition to Rust, Protobuf and SQL

Minimal example showcasing what is being generated from an ASN.1 definition:

```asn MyMessages DEFINITIONS AUTOMATIC TAGS ::= BEGIN

Header ::= SEQUENCE { timestamp INTEGER (0..1209600000) }

END ```

The generated Rust file:

```rust use asn1rs::prelude::*;

[asn(sequence)]

[derive(Default, Debug, Clone, PartialEq, Hash)]

pub struct Header { #[asn(integer(0..1209600000))] pub timestamp: u32, }

// OPTIONAL: Insert and query functions for async PostgreSQL impl Header { pub async fn apsqlretrievemany(context: &apsql::Context<'>, ids: &[i32]) -> Result, apsql::Error> { /*..*/ } pub async fn apsqlretrieve(context: &apsql::Context<'>, id: i32) -> Result { /*..*/ } pub async fn apsqlload(context: &apsql::Context<'>, row: &apsql::Row) -> Result { /*..*/ } pub async fn apsqlinsert(&self, context: &apsql::Context<'_>) -> Result { /../ } }

// OPTIONAL: Serialize and deserialize functions for protobuf impl ProtobufEq for Header { /../ } impl Protobuf for Header { /../ }

// OPTIONAL: Insert and query functions for non-async PostgreSQL impl PsqlRepresentable for Header { /../ } impl PsqlInsertable for Header { /../ } impl PsqlQueryable for Header { /../ } ```

OPTIONAL: The generated protobuf file:

```proto syntax = 'proto3'; package my.messages;

message Header { uint32 timestamp = 1; } ```

OPTIONAL: The generated (p)sql file:

```sql DROP TABLE IF EXISTS Header CASCADE;

CREATE TABLE Header ( id SERIAL PRIMARY KEY, timestamp INTEGER NOT NULL ); ```

Example usage of async postgres

NOTE: This requires the async-psql feature.

Using async postgres allows the message - or the batched messages - to take advantage of [pipelining] automatically. This can provide a speedup (personal experience: at around 26%) compared to the synchronous/blocking postgres implementation.

```rust use asn1rs::io::asyncpsql::*; use tokiopostgres::NoTls;

[tokio::main]

async fn main() { let transactional = true; let (mut client, connection) = tokiopostgres::connect( "host=localhost user=postgres applicationname=psqlasyncdemo", NoTls, ) .await .expect("Failed to connect");

tokio::spawn(connection);


let context = if transactional {
    let transaction = client
        .transaction()
        .await
        .expect("Failed to open a new transaction");
    Cache::default().into_transaction_context(transaction)
} else {
    Cache::default().into_client_context(client)
};

// using sample message from above
let message = Header {
    timestamp: 1234,
};

// This issues all necessary insert statements on the given Context and
// because it does not require exclusive access to the context, you can
// issue multiple inserts and await them concurrently with for example
// tokio::try_join, futures::try_join_all or the like. 
let id = message.apsql_insert(&context).await.expect("Insert failed");

// This disassembles the context, allowing the Transaction to be committed
// or rolled back. This operation also optimizes the read access to
// prepared statements of the Cache. If you do not want to do that, then call
// Context::split_unoptimized instead.
// You can also call `Cache::optimize()` manually to optimize the read access
// to the cached prepared statements.
// See the doc for more information about the usage of cached prepared statements
let (mut cache, transaction) = context.split();

// this is (logically) a nop on a non-transactional context
transaction.commit().await.expect("failed to commit");

let context = if transactional {
    let transaction = client
        .transaction()
        .await
        .expect("Failed to open a new transaction");
    Cache::default().into_transaction_context(transaction)
} else {
    Cache::default().into_client_context(client)
};

let message_from_db = Header::apsql_retrieve(&context, id).await.expect("Failed to load");
assert_eq!(message, message_from_db);

} ```

Raw uPER usage

The module asn1rs::io exposes (de-)serializers and helpers for direct usage without ASN.1 definition: ```rust use asn1rs::prelude::*; use asn1rs::io::per::unaligned::buffer::BitBuffer;

let mut buffer = BitBuffer::default(); buffer.writebit(true).unwrap(); buffer.writeutf8_string("My UTF8 Text").unwrap();

sendtoanother_host(buffer.into::>()): ```

Raw Protobuf usage

The module asn1rs::io::protobuf exposes (de-)serializers for protobuf usage: ```rust use asn1rs::io::protobuf::*;

let mut buffer = Vec::default(); buffer.writevarint(1337).unwrap(); buffer.writestring("Still UTF8 Text").unwrap();

sendtoanother_host(buffer): ```

TODO

Things to do at some point in time (PRs are welcome)

• generate a proper rust module hierarchy from the modules' object-identifier
• remove legacy rust+uper code generator (probably in 0.3)
• support #![no_std]
• refactor / clean-up (rust) code-generators
• support more encoding formats of ASN.1

License

<sup>Licensed under either of Apache License, Version 2.0 or MIT license at your option.</sup>

<sub>Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.</sub>

Origin

<sub>This crate was initially developed during a research project at IT-Designers GmbH (http://www.it-designers.de).</sub>