refactor: unify client IP extraction into extract_real_ip

Replace extract_client_ip (manual header parsing without proxy
verification) and is_valid_ip with a single extract_real_ip function
that uses the same proxy-checking logic as RealIpKeyExtractor.

- If peer IP == trusted proxy: use realip_remote_addr() (Forwarded/
  X-Forwarded-For) — safe because peer was verified
- Otherwise: use peer_addr() directly (local/direct connection)

echo_info now extracts the trusted proxy from web::Data<IpAddr>
and passes it to extract_real_ip, ensuring consistent IP resolution
across rate limiting and address derivation.

src/bin/bal-server.rs

@@ -227,8 +227,19 @@ async fn echo_version() -> impl Responder {
     HttpResponse::Ok().body(VERSION)
 }
 
-fn is_valid_ip(ip: &str) -> bool {
+fn extract_real_ip(req: &actix_web::HttpRequest, trusted_proxy: IpAddr) -> String {
-    ip.parse::<std::net::IpAddr>().is_ok()
+    let peer_ip = req.peer_addr().map(|socket| socket.ip());
+    let connection_info = req.connection_info();
+
+    let ip = match peer_ip {
+        Some(peer) if peer == trusted_proxy => {
+            connection_info.realip_remote_addr().unwrap_or("unknown")
+        }
+        _ => connection_info.peer_addr().unwrap_or("unknown"),
+    };
+
+    debug!("client IP: {}", ip);
+    ip.to_string()
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -276,37 +287,10 @@ impl KeyExtractor for RealIpKeyExtractor {
     }
 }
 
-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>,
+    proxy: web::Data<IpAddr>,
     req: actix_web::HttpRequest,
 ) -> impl Responder {
     let param = path.into_inner();
@@ -319,7 +303,7 @@ async fn echo_info(
         debug!("network disabled {}", param);
         return HttpResponse::BadRequest().body("error");
     }
-    let remote_addr = extract_client_ip(&req);
+    let remote_addr = extract_real_ip(&req, **proxy);
     let address = match netconfig.xpub {
         false => {
             let address = netconfig.address.to_string();