lib: add lte-parser crate support

This'll let us convert a Gsmtap message into a fully parsed LTE
message.

lte-parser/Cargo.toml

@@ -5,28 +5,11 @@ edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
-[build-dependencies]
-asn1-compiler = "0.6.1"
-asn1-codecs = "0.6.1"
-asn1_codecs_derive = "0.6.1"
-serde = { version = "1.0" , features = ["derive"]}
-trybuild = { version = "1.0" }
-hex = { version = "0.4" }
-bitvec = { version = "1.0" , features = ["serde"]}
-log = { version = "0.4" }
-criterion = { version = "0.5" , features = ["rayon"]}
-env_logger = { version = "0.9" }
-
 [dependencies]
 asn1-compiler = "0.6.1"
 asn1-codecs = "0.6.1"
 asn1_codecs_derive = "0.6.1"
-bitvec = "1.0"
-log = "0.4"
-
-[dev-dependencies]
-asn1-compiler = "0.6.1"
-asn1-codecs = "0.6.1"
-asn1_codecs_derive = "0.6.1"
-bitvec = "1.0"
+bitvec = { version = "1.0", features = ["serde"] }
 log = "0.4"
+thiserror = "1.0.56"
+serde = { version = "1.0.196", features = ["derive"] }

lte-parser/README.md

@@ -6,7 +6,7 @@ Rust code for parsing these messages. We're using [hampi](https://github.com/yst
 
 ## Generating the parser
 
-To install the hampi tools, run:
+To install the hampi compiler, run:
 
 ```
 > cargo install asn1-compiler
@@ -15,7 +15,7 @@ To install the hampi tools, run:
 To generate the parser, run:
 
 ```
-> ampi-rs-asn1c --codec uper --module src/lte_rrc.rs -- specs/*
+> hampi-rs-asn1c --codec uper --derive clone --derive partial-eq --derive serialize --module src/lte_rrc.rs -- specs/*
 ```
 
 ## Sourcing the ASN.1 files

lte-parser/src/lib.rs

@@ -1,2 +1,18 @@
+use asn1_codecs::{uper::UperCodec, PerCodecData, PerCodecError};
+use thiserror::Error;
 #[allow(unreachable_patterns, non_camel_case_types)]
 pub mod lte_rrc;
+
+#[derive(Error, Debug)]
+pub enum ParsingError {
+    #[error("Failed to decode UPER data: {0}")]
+    UperDecodeError(PerCodecError),
+}
+
+pub fn decode<T>(data: &[u8]) -> Result<T, ParsingError>
+    where T: UperCodec<Output = T>
+{
+    let mut asn_data = PerCodecData::from_slice_uper(data);
+    T::uper_decode(&mut asn_data)
+        .map_err(|e| ParsingError::UperDecodeError(e))
+}