Cleaned up the protocol layer and metadata

- request() now reads exactly the expected response length with
  read_exact instead of a single non-guaranteed fill_buf, fixing a
  latent bug where a response split across multiple TCP packets could
  be mistaken for malformed data; the per-method length checks are now
  redundant and were removed
- sequence_number wraps explicitly via wrapping_add instead of
  relying on implicit (and debug-vs-release inconsistent) overflow
  behavior after 65536 requests
- get_name validates UTF-8 strictly instead of silently lossy-decoding
  invalid bytes; on invalid data it now returns the FromUtf8Error
  itself (byte-level \0 trimming moved after the UTF-8 check), letting
  the caller choose to fail or fall back to a lossy rendering
- removed the unused Default derive from Clock and Record
- removed npm from the CI image (no JS/Node in this repo), fixed a
  typo in a CI step name
- fixed the Cargo.toml license field to the actual SPDX identifier
  (AGPL-3.0-or-later, per the notice at the end of LICENSE) instead of
  the free-text "GNU AGPLv3.0"

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitea/workflows/check-format-and-test.yaml

@@ -11,7 +11,7 @@ jobs:
         run: |
           rustup component add clippy rustfmt &&
           apk update &&
-          apk add musl-dev git npm
+          apk add musl-dev git
 
       - name: Checkout the code
         uses: actions/checkout@v3
@@ -27,5 +27,5 @@ jobs:
       - name: Check if the code is formatted correctly
         run: cargo fmt --check
 
-      - name: Check if Clippy has someting to say
+      - name: Check if Clippy has something to say
         run: cargo clippy --all-targets

Cargo.toml

@@ -2,7 +2,7 @@
 name = "r701"
 version = "0.1.0"
 edition = "2021"
-license = "GNU AGPLv3.0"
+license = "AGPL-3.0-or-later"
 repository = "https://git.nicolabelluti.me/nicolabelluti/r701"
 
 [dependencies]

README.md

@@ -45,11 +45,11 @@ If you want to read about this reverse engineering attempt, check out
        println!("No\tMchn\tEnNo\t\tName\t\tMode\tIOMd\tDateTime\t");
        while let Some(record) = record_stream.next().await {
            let record = record.unwrap();
-           let name = r701
-               .get_name(record.employee_id)
-               .await
-               .unwrap()
-               .unwrap_or(format!("user #{}", record.employee_id));
+           let name = match r701.get_name(record.employee_id).await.unwrap() {
+               Some(Ok(name)) => name,
+               Some(Err(error)) => String::from_utf8_lossy(error.as_bytes()).into_owned(),
+               None => format!("user #{}", record.employee_id),
+           };
 
            println!(
                "{:0>6}\t{}\t{:0>9}\t{: <10}\t{}\t{}\t{}",

src/r701.rs

@@ -1,6 +1,6 @@
 use crate::RecordIterator;
 use std::io::{Error, ErrorKind::InvalidData, Result};
-use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio::net::{TcpStream, ToSocketAddrs};
 use tokio::sync::Mutex;
 
@@ -35,7 +35,7 @@ impl R701 {
     // The lock must stay held for the whole write+read round-trip, so that
     // concurrent callers can't interleave their requests on the wire
     #[allow(clippy::significant_drop_tightening)]
-    pub async fn request(&self, payload: &[u8; 12]) -> Result<Vec<u8>> {
+    pub async fn request(&self, payload: &[u8; 12], response_len: usize) -> Result<Vec<u8>> {
         let mut state = self.state.lock().await;
 
         // Create a blank request
@@ -46,14 +46,16 @@ impl R701 {
 
         // Insert the sequence number
         request[14..].clone_from_slice(&state.sequence_number.to_le_bytes());
-        state.sequence_number += 1;
+        state.sequence_number = state.sequence_number.wrapping_add(1);
 
         // Send the request
         state.tcp_stream.write_all(&request).await?;
 
-        // Create a buffer and return the response
-        let mut buffer = BufReader::new(&mut state.tcp_stream);
-        Ok(buffer.fill_buf().await?.to_vec())
+        // Read exactly response_len bytes, looping over multiple reads if
+        // the response arrives split across several TCP packets
+        let mut buffer = vec![0u8; response_len];
+        state.tcp_stream.read_exact(&mut buffer).await?;
+        Ok(buffer)
     }
 
     #[allow(clippy::missing_errors_doc)]
@@ -61,7 +63,7 @@ impl R701 {
         // Create a request with a payload of `01 80 00 00 00 00 00 00 00 00 00
         // 00` and get the response
         let response = self
-            .request(&[0x01, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])
+            .request(&[0x01, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 10)
             .await?;
 
         // If the response is not `aa 55 01 01 00 00 00 00 00 00` then return an
@@ -74,39 +76,38 @@ impl R701 {
     }
 
     #[allow(clippy::missing_errors_doc)]
-    pub async fn get_name(&self, id: u32) -> Result<Option<String>> {
+    pub async fn get_name(
+        &self,
+        id: u32,
+    ) -> Result<Option<std::result::Result<String, std::string::FromUtf8Error>>> {
         // Create a request with a payload of `01 c7 xx xx xx xx 00 00 00 00 14
         // 00`, where `xx xx xx xx` is the employee ID in little endian
         let mut request = [0x01, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0x14, 0];
         request[2..6].clone_from_slice(&id.to_le_bytes());
 
         // Get the response
-        let response = self.request(&request).await?;
+        let response = self.request(&request, 34).await?;
 
-        // If the response length is right but the header is `01 00 00 00 00 00
-        // 00 00` then the request is been succesful but the name was not found
-        if response.len() == 34
-            && response[..12] == [0xaa, 0x55, 0x01, 0, 0, 0, 0, 0, 0, 0, 0x55, 0xaa]
-        {
+        // If the header is `01 00 00 00 00 00 00 00` then the request has
+        // been succesful but the name was not found
+        if response[..12] == [0xaa, 0x55, 0x01, 0, 0, 0, 0, 0, 0, 0, 0x55, 0xaa] {
             return Ok(None);
         }
 
-        // If one between the response length or the response header is wrong
-        // return an error
-        if response.len() != 34
-            || response[..12] != [0xaa, 0x55, 0x01, 0x01, 0, 0, 0, 0, 0, 0, 0x55, 0xaa]
-        {
+        // If the response header is wrong return an error
+        if response[..12] != [0xaa, 0x55, 0x01, 0x01, 0, 0, 0, 0, 0, 0, 0x55, 0xaa] {
             return Err(Error::new(InvalidData, "Malformed response"));
         }
 
         // Get the name as a UTF-8 string and delete the `\0` at the end
-        let name = String::from_utf8_lossy(&response[12..22])
-            .trim_end_matches('\0')
-            .to_string();
+        let name = match String::from_utf8(response[12..22].to_vec()) {
+            Ok(name) => name.trim_end_matches('\0').to_string(),
+            Err(error) => return Ok(Some(Err(error))),
+        };
 
         // Return None if the name is empty, else return the name wrapped into a
         // Some
-        Ok(Some(name).filter(|name| !name.is_empty()))
+        Ok(Some(name).filter(|name| !name.is_empty()).map(Ok))
     }
 
     #[allow(clippy::missing_errors_doc)]
@@ -114,15 +115,12 @@ impl R701 {
         // Create a request with a payload of `01 b4 08 00 00 00 00 00 ff ff 00
         // 00` and get the response
         let response = self
-            .request(&[0x01, 0xb4, 0x08, 0, 0, 0, 0, 0, 0xff, 0xff, 0, 0])
+            .request(&[0x01, 0xb4, 0x08, 0, 0, 0, 0, 0, 0xff, 0xff, 0, 0], 10)
             .await?;
 
-        // If one between the response length or the response header is wrong
+        // If one between the response header or the trailing bytes is wrong
         // return an error
-        if response.len() != 10
-            || response[..4] != [0xaa, 0x55, 0x01, 0x01]
-            || response[6..] != [0u8; 4]
-        {
+        if response[..4] != [0xaa, 0x55, 0x01, 0x01] || response[6..] != [0u8; 4] {
             return Err(Error::new(InvalidData, "Malformed response"));
         }
 
@@ -155,12 +153,11 @@ impl R701 {
         }
 
         // Get the response
-        let response = self.request(&request).await?;
+        let response = self.request(&request, 1038).await?;
 
-        // If one between the response length, the response header or the last
-        // two bits is wrong return an error
-        if response.len() != 1038
-            || response[..12] != [0xaa, 0x55, 0x01, 0x01, 0, 0, 0, 0, 0, 0, 0x55, 0xaa]
+        // If one between the response header or the last two bits is wrong
+        // return an error
+        if response[..12] != [0xaa, 0x55, 0x01, 0x01, 0, 0, 0, 0, 0, 0, 0x55, 0xaa]
             || response[1036..] != [0, 0]
         {
             return Err(Error::new(InvalidData, "Malformed response"));

src/record.rs

@@ -2,20 +2,16 @@ use chrono::{DateTime, Local, TimeZone};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
-#[derive(Debug, Clone, Copy, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum Clock {
-    #[default]
     FirstIn,
     FirstOut,
     SecondIn,
     SecondOut,
 }
 
-// unsafe impl Send for Clock {}
-// unsafe impl Sync for Clock {}
-
-#[derive(Debug, Clone, Copy, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Record {
     pub employee_id: u32,
@@ -23,9 +19,6 @@ pub struct Record {
     pub datetime: DateTime<Local>,
 }
 
-// unsafe impl Send for Record {}
-// unsafe impl Sync for Record {}
-
 impl TryFrom<&[u8]> for Record {
     type Error = &'static str;