fix: extract client IP correctly behind reverse proxy

Add X-Forwarded-For as fallback header when X-Real-IP is missing.
Validate IP format before storing. Log which source was used.

release: bal-server-0.3.2

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bal_server"
-version = "0.3.1"
+version = "0.3.2"
 edition = "2024"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

src/bin/bal-server.rs

@@ -217,6 +217,38 @@ async fn echo_version() -> impl Responder {
     HttpResponse::Ok().body(VERSION)
 }
 
+fn is_valid_ip(ip: &str) -> bool {
+    ip.parse::<std::net::IpAddr>().is_ok()
+}
+
+fn extract_client_ip(req: &actix_web::HttpRequest) -> String {
+    if let Some(val) = req.headers().get("X-Real-IP")
+        && let Ok(s) = val.to_str()
+    {
+        let ip = s.split(',').next().unwrap_or(s).trim();
+        if is_valid_ip(ip) {
+            debug!("client IP from X-Real-IP: {}", ip);
+            return ip.to_string();
+        }
+    }
+    if let Some(val) = req.headers().get("X-Forwarded-For")
+        && let Ok(s) = val.to_str()
+    {
+        let ip = s.split(',').next().unwrap_or(s).trim();
+        if is_valid_ip(ip) {
+            debug!("client IP from X-Forwarded-For: {}", ip);
+            return ip.to_string();
+        }
+    }
+    let fallback = req
+        .connection_info()
+        .peer_addr()
+        .unwrap_or("unknown")
+        .to_string();
+    debug!("client IP from peer_addr fallback: {}", fallback);
+    fallback
+}
+
 async fn echo_info(
     path: web::Path<String>,
     data: web::Data<AppState>,
@@ -232,18 +264,7 @@ async fn echo_info(
         debug!("network disabled {}", param);
         return HttpResponse::BadRequest().body("error");
     }
-    let remote_addr = req
-        .headers()
-        .get("X-Real-IP")
-        .and_then(|value| value.to_str().ok())
-        .and_then(|xff| xff.split(',').next())
-        .map(|ip| ip.trim().to_string())
-        .unwrap_or_else(|| {
-            req.connection_info()
-                .peer_addr()
-                .unwrap_or("unknown")
-                .to_string()
-        });
+    let remote_addr = extract_client_ip(&req);
     let address = match netconfig.xpub {
         false => {
             let address = netconfig.address.to_string();