diff --git a/src/hbbr/main.rs b/src/hbbr/main.rs
index 8edd5e7..e33080f 100644
--- a/src/hbbr/main.rs
+++ b/src/hbbr/main.rs
@@ -1,22 +1,7 @@
 use clap::App;
-use hbb_common::{
-    env_logger::*,
-    log,
-    protobuf::Message as _,
-    rendezvous_proto::*,
-    sleep,
-    tcp::{new_listener, FramedStream},
-    tokio, ResultType,
-};
-use std::{
-    collections::HashMap,
-    net::SocketAddr,
-    sync::{Arc, Mutex},
-};
-
-lazy_static::lazy_static! {
-    static ref PEERS: Arc<Mutex<HashMap<String, FramedStream>>> = Arc::new(Mutex::new(HashMap::new()));
-}
+mod relay_server;
+use hbb_common::{env_logger::*, tokio, ResultType};
+use relay_server::start;
 
 const DEFAULT_PORT: &'static str = "21117";
 
@@ -33,68 +18,6 @@ async fn main() -> ResultType<()> {
         .about("RustDesk Relay Server")
         .args_from_usage(&args)
         .get_matches();
-    let addr = format!(
-        "0.0.0.0:{}",
-        matches.value_of("port").unwrap_or(DEFAULT_PORT)
-    );
-    log::info!("Listening on {}", addr);
-    let mut listener = new_listener(addr, false).await?;
-    loop {
-        tokio::select! {
-            Ok((stream, addr)) = listener.accept() => {
-                tokio::spawn(async move {
-                    make_pair(FramedStream::from(stream), addr).await.ok();
-                });
-            }
-        }
-    }
-}
-
-async fn make_pair(stream: FramedStream, addr: SocketAddr) -> ResultType<()> {
-    let mut stream = stream;
-    if let Some(Ok(bytes)) = stream.next_timeout(30_000).await {
-        if let Ok(msg_in) = RendezvousMessage::parse_from_bytes(&bytes) {
-            if let Some(rendezvous_message::Union::request_relay(rf)) = msg_in.union {
-                if !rf.uuid.is_empty() {
-                    let peer = PEERS.lock().unwrap().remove(&rf.uuid);
-                    if let Some(peer) = peer {
-                        log::info!("Forward request {} from {} got paired", rf.uuid, addr);
-                        return relay(stream, peer).await;
-                    } else {
-                        log::info!("New relay request {} from {}", rf.uuid, addr);
-                        PEERS.lock().unwrap().insert(rf.uuid.clone(), stream);
-                        sleep(30.).await;
-                        PEERS.lock().unwrap().remove(&rf.uuid);
-                    }
-                }
-            }
-        }
-    }
-    Ok(())
-}
-
-async fn relay(stream: FramedStream, peer: FramedStream) -> ResultType<()> {
-    let mut peer = peer;
-    let mut stream = stream;
-    peer.set_raw();
-    stream.set_raw();
-    loop {
-        tokio::select! {
-            res = peer.next() => {
-                if let Some(Ok(bytes)) = res {
-                    stream.send_bytes(bytes.into()).await?;
-                } else {
-                    break;
-                }
-            },
-            res = stream.next() => {
-                if let Some(Ok(bytes)) = res {
-                    peer.send_bytes(bytes.into()).await?;
-                } else {
-                    break;
-                }
-            },
-        }
-    }
+    start(matches.value_of("port").unwrap_or(DEFAULT_PORT)).await?;
     Ok(())
 }
diff --git a/src/hbbr/relay_server.rs b/src/hbbr/relay_server.rs
new file mode 100644
index 0000000..9becb4c
--- /dev/null
+++ b/src/hbbr/relay_server.rs
@@ -0,0 +1,81 @@
+use hbb_common::{
+    log,
+    protobuf::Message as _,
+    rendezvous_proto::*,
+    sleep,
+    tcp::{new_listener, FramedStream},
+    tokio, ResultType,
+};
+use std::{
+    collections::HashMap,
+    net::SocketAddr,
+    sync::{Arc, Mutex},
+};
+
+lazy_static::lazy_static! {
+    static ref PEERS: Arc<Mutex<HashMap<String, FramedStream>>> = Arc::new(Mutex::new(HashMap::new()));
+}
+
+pub async fn start(port: &str) -> ResultType<()> {
+    let addr = format!("0.0.0.0:{}", port);
+    log::info!("Listening on {}", addr);
+    let mut listener = new_listener(addr, false).await?;
+    loop {
+        tokio::select! {
+            Ok((stream, addr)) = listener.accept() => {
+                tokio::spawn(async move {
+                    make_pair(FramedStream::from(stream), addr).await.ok();
+                });
+            }
+        }
+    }
+}
+
+async fn make_pair(stream: FramedStream, addr: SocketAddr) -> ResultType<()> {
+    let mut stream = stream;
+    if let Some(Ok(bytes)) = stream.next_timeout(30_000).await {
+        if let Ok(msg_in) = RendezvousMessage::parse_from_bytes(&bytes) {
+            if let Some(rendezvous_message::Union::request_relay(rf)) = msg_in.union {
+                if !rf.uuid.is_empty() {
+                    let peer = PEERS.lock().unwrap().remove(&rf.uuid);
+                    if let Some(peer) = peer {
+                        log::info!("Forward request {} from {} got paired", rf.uuid, addr);
+                        return relay(stream, peer).await;
+                    } else {
+                        log::info!("New relay request {} from {}", rf.uuid, addr);
+                        PEERS.lock().unwrap().insert(rf.uuid.clone(), stream);
+                        sleep(30.).await;
+                        PEERS.lock().unwrap().remove(&rf.uuid);
+                    }
+                }
+            }
+        }
+    }
+    Ok(())
+}
+
+async fn relay(stream: FramedStream, peer: FramedStream) -> ResultType<()> {
+    let mut peer = peer;
+    let mut stream = stream;
+    peer.set_raw();
+    stream.set_raw();
+    loop {
+        tokio::select! {
+            res = peer.next() => {
+                if let Some(Ok(bytes)) = res {
+                    stream.send_bytes(bytes.into()).await?;
+                } else {
+                    break;
+                }
+            },
+            res = stream.next() => {
+                if let Some(Ok(bytes)) = res {
+                    peer.send_bytes(bytes.into()).await?;
+                } else {
+                    break;
+                }
+            },
+        }
+    }
+    Ok(())
+}