Refactor lib/binary into separate crates

wavehunter/src/main.rs

@@ -0,0 +1,233 @@
+use axum::body::Body;
+use axum::http::header::CONTENT_TYPE;
+use futures_core::Stream;
+use log::error;
+use wavehunter::diag_device::{DiagDevice, DiagDeviceError};
+use wavehunter::diag_reader::DiagReader;
+use wavehunter::gsmtap_parser::GsmtapParser;
+use wavehunter::pcap::GsmtapPcapWriter;
+
+use axum::Router;
+use axum::extract::State;
+use axum::http::StatusCode;
+use axum::response::{Response, IntoResponse};
+use axum::routing::get;
+use std::fs::File;
+use thiserror::Error;
+use serde::Deserialize;
+use wavehunter::qmdl::{QmdlReader, QmdlReaderError};
+use std::io::Write;
+use std::sync::Arc;
+use std::net::SocketAddr;
+use std::pin::Pin;
+use std::task::{Poll, Context};
+use tokio::net::TcpListener;
+use tokio::sync::{mpsc, RwLock};
+use toml;
+
+#[derive(Error, Debug)]
+enum WavehunterError {
+    #[error("Missing config file: {0}")]
+    MissingConfigFile(String),
+    #[error("Config file parsing error: {0}")]
+    ConfigFileParsingError(#[from] toml::de::Error),
+    #[error("Diag intialization error: {0}")]
+    DiagInitError(DiagDeviceError),
+    #[error("Diag read error: {0}")]
+    DiagReadError(DiagDeviceError),
+    #[error("Tokio error: {0}")]
+    TokioError(#[from] tokio::io::Error),
+}
+
+#[derive(Deserialize)]
+struct ConfigFile {
+    qmdl_path: Option<String>,
+    port: Option<u16>,
+}
+
+#[derive(Debug)]
+struct Config {
+    qmdl_path: String,
+    port: u16,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Config {
+            qmdl_path: "./wavehunter.qmdl".to_string(),
+            port: 8080,
+        }
+    }
+}
+
+fn parse_config<P>(path: P) -> Result<Config, WavehunterError> where P: AsRef<std::path::Path> {
+    let config_file = std::fs::read_to_string(&path)
+        .map_err(|_| WavehunterError::MissingConfigFile(format!("{:?}", path.as_ref())))?;
+    let parsed_config: ConfigFile = toml::from_str(&config_file)
+        .map_err(WavehunterError::ConfigFileParsingError)?;
+    let mut config = Config::default();
+    parsed_config.qmdl_path.map(|path| config.qmdl_path = path);
+    parsed_config.port.map(|path| config.port = path);
+    Ok(config)
+}
+
+struct Args {
+    config_path: String,
+}
+
+fn parse_args() -> Args {
+    let args: Vec<String> = std::env::args().collect();
+    if args.len() != 2 {
+        println!("Usage: {} /path/to/config/file", args[0]);
+        std::process::exit(1);
+    }
+    Args {
+        config_path: args[1].clone(),
+    }
+}
+
+fn run_diag_read_thread(mut dev: DiagDevice, bytes_read_lock: Arc<RwLock<usize>>) -> tokio::task::JoinHandle<Result<(), WavehunterError>> {
+    tokio::task::spawn_blocking(move || {
+        loop {
+            // TODO: once we're actually doing analysis, we'll wanna use the messages
+            // returned here. Until then, the DiagDevice has already written those messages
+            // to the QMDL file, so we can just ignore them.
+            let _messages = dev.read_response().map_err(WavehunterError::DiagReadError)?;
+
+            // keep track of how many bytes were written to the QMDL file so we can read
+            // a valid block of data from it in the HTTP server
+            let mut bytes_read = bytes_read_lock.blocking_write();
+            *bytes_read = dev.qmdl_writer.total_written;
+        }
+    })
+}
+
+// Streams a pcap file chunk-by-chunk to the client by reading the QMDL data
+// written so far. This is done by spawning a blocking thread (a tokio thread
+// capable of handling blocking operations) which streams chunks of pcap data to
+// a channel that's piped to the client.
+async fn serve_pcap(State(state): State<Arc<ServerState>>) -> Result<Response, (StatusCode, String)> {
+    let qmdl_bytes_written = *state.qmdl_bytes_written.read().await;
+    if qmdl_bytes_written == 0 {
+        return Err((
+            StatusCode::SERVICE_UNAVAILABLE,
+            "QMDL file is empty, try again in a bit!".to_string()
+        ));
+    }
+
+    let (tx, rx) = mpsc::channel(1);
+    let channel_reader = ChannelReader { rx };
+    let channel_writer = ChannelWriter { tx };
+    tokio::task::spawn_blocking(move || {
+        // the QMDL reader should stop at the last successfully written data
+        // chunk (qmdl_bytes_written)
+        let qmdl_file = File::open(&state.qmdl_path).unwrap();
+        let mut qmdl_reader = QmdlReader::new(qmdl_file, Some(qmdl_bytes_written));
+
+        let mut gsmtap_parser = GsmtapParser::new();
+        let mut pcap_writer = GsmtapPcapWriter::new(channel_writer).unwrap();
+        pcap_writer.write_iface_header().unwrap();
+        loop {
+            match qmdl_reader.read_response() {
+                Ok(messages) => {
+                    for maybe_msg in messages {
+                        match maybe_msg {
+                            Ok(msg) => {
+                                let maybe_gsmtap_msg = gsmtap_parser.recv_message(msg)
+                                    .expect("error parsing gsmtap message");
+                                if let Some((timestamp, gsmtap_msg)) = maybe_gsmtap_msg {
+                                    pcap_writer.write_gsmtap_message(gsmtap_msg, timestamp)
+                                        .expect("error writing pcap packet");
+                                }
+                            },
+                            Err(e) => {
+                                error!("error parsing message: {:?}", e);
+                            },
+                        }
+                    }
+                },
+                // this is expected, and just means we've reached the end of the
+                // safely written QMDL data
+                Err(QmdlReaderError::MaxBytesReached(_)) => break,
+                Err(e) => {
+                    error!("error reading qmdl file: {:?}", e);
+                    break;
+                },
+            }
+        }
+    });
+
+    let headers = [(CONTENT_TYPE, "application/vnd.tcpdump.pcap")];
+    let body = Body::from_stream(channel_reader);
+    Ok((headers, body).into_response())
+}
+
+struct ChannelWriter {
+    tx: mpsc::Sender<Vec<u8>>,
+}
+
+impl Write for ChannelWriter {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        self.tx.blocking_send(buf.to_vec())
+            .map_err(|_| std::io::Error::new(std::io::ErrorKind::Other, "channel closed"))?;
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
+
+struct ChannelReader {
+    rx: mpsc::Receiver<Vec<u8>>,
+}
+
+impl Stream for ChannelReader {
+    type Item = Result<Vec<u8>, String>;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        match self.rx.poll_recv(cx) {
+            Poll::Ready(Some(msg)) => Poll::Ready(Some(Ok(msg))),
+            Poll::Ready(None) => Poll::Ready(None),
+            Poll::Pending => Poll::Pending,
+        }
+    }
+}
+
+struct ServerState {
+    qmdl_bytes_written: Arc<RwLock<usize>>,
+    qmdl_path: String,
+}
+
+#[tokio::main]
+async fn main() -> Result<(), WavehunterError> {
+    env_logger::init();
+
+    let args = parse_args();
+    let config = parse_config(&args.config_path)?;
+
+    let mut dev = DiagDevice::new(&config.qmdl_path)
+        .map_err(WavehunterError::DiagInitError)?;
+    dev.config_logs()
+        .map_err(WavehunterError::DiagInitError)?;
+
+    let qmdl_bytes_lock = Arc::new(RwLock::new(dev.qmdl_writer.total_written));
+    // TODO: handle exiting gracefully
+    let _read_thread_handle = run_diag_read_thread(dev, qmdl_bytes_lock.clone());
+
+    println!("The orca is hunting for stingrays...");
+
+    let addr = SocketAddr::from(([127, 0, 0, 1], config.port));
+    let listener = TcpListener::bind(&addr).await?;
+    let state = Arc::new(ServerState {
+        qmdl_bytes_written: qmdl_bytes_lock,
+        qmdl_path: config.qmdl_path,
+    });
+
+    let app = Router::new()
+        .route("/output.pcap", get(serve_pcap))
+        .with_state(state);
+    axum::serve(listener, app).await.unwrap();
+
+    Ok(())
+}