feat: Initial implementation

Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>

filtermail/src/main.rs

@@ -0,0 +1,75 @@
+mod config;
+pub(crate) mod error;
+pub(crate) mod inbound;
+pub(crate) mod message;
+pub(crate) mod openpgp;
+pub(crate) mod outbound;
+pub(crate) mod rate_limiter;
+pub(crate) mod smtp_server;
+pub(crate) mod utils;
+
+use config::Config;
+use env_logger::Env;
+use inbound::IncomingBeforeQueueHandler;
+use outbound::OutgoingBeforeQueueHandler;
+use smtp_server::run_smtp_server;
+use std::env;
+use std::process;
+use std::sync::Arc;
+
+const ENCRYPTION_NEEDED_523: &str = "523 Encryption Needed: Invalid Unencrypted Mail";
+
+#[tokio::main]
+async fn main() {
+    // default to info level
+    let env = Env::new().filter_or("RUST_LOG", "info");
+    env_logger::Builder::from_env(env)
+        // disable timestamps - automatically added by systemd
+        .format_timestamp(None)
+        .init();
+
+    let args: Vec<String> = env::args().collect();
+    if args.len() != 3 {
+        eprintln!("Usage: {} <config_file> <mode>", args[0]);
+        eprintln!("  mode: incoming or outgoing");
+        process::exit(1);
+    }
+
+    let config_path = &args[1];
+    let mode = &args[2];
+
+    if mode != "incoming" && mode != "outgoing" {
+        eprintln!("Error: mode must be 'incoming' or 'outgoing'");
+        process::exit(1);
+    }
+
+    let config = match Config::from_file(config_path) {
+        Ok(c) => c,
+        Err(e) => {
+            eprintln!("Failed to read config: {}", e);
+            process::exit(1);
+        }
+    };
+
+    if mode == "outgoing" {
+        let handler = Arc::new(OutgoingBeforeQueueHandler::new(config.clone()));
+        let addr = format!("127.0.0.1:{}", config.filtermail_smtp_port);
+        let max_size = config.max_message_size;
+        log::debug!("Outgoing SMTP server listening on {}", addr);
+
+        if let Err(e) = run_smtp_server(&addr, handler, max_size).await {
+            eprintln!("Server error: {}", e);
+            process::exit(1);
+        }
+    } else {
+        let handler = Arc::new(IncomingBeforeQueueHandler::new(config.clone()));
+        let addr = format!("127.0.0.1:{}", config.filtermail_smtp_port_incoming);
+        let max_size = config.max_message_size;
+        log::debug!("Incoming SMTP server listening on {}", addr);
+
+        if let Err(e) = run_smtp_server(&addr, handler, max_size).await {
+            eprintln!("Server error: {}", e);
+            process::exit(1);
+        }
+    }
+}