diff --git a/broker/src/chain_tracker.rs b/broker/src/chain_tracker.rs
new file mode 100644
index 0000000..06cd663
--- /dev/null
+++ b/broker/src/chain_tracker.rs
@@ -0,0 +1,41 @@
+use crate::{ChannelReply, ChannelRequest};
+use async_trait::async_trait;
+use tokio::sync::{mpsc, oneshot};
+use vls_protocol::{Error, Result};
+use vls_protocol_client::SignerPort;
+
+pub struct MqttSignerPort {
+    sender: mpsc::Sender<ChannelRequest>,
+}
+
+#[async_trait]
+impl SignerPort for MqttSignerPort {
+    async fn handle_message(&self, message: Vec<u8>) -> Result<Vec<u8>> {
+        let reply_rx = self.send_request(message).await?;
+        self.get_reply(reply_rx).await
+    }
+
+    fn clone(&self) -> Box<dyn SignerPort> {
+        Box::new(Self {
+            sender: self.sender.clone(),
+        })
+    }
+}
+
+impl MqttSignerPort {
+    pub fn new(sender: mpsc::Sender<ChannelRequest>) -> Self {
+        Self { sender }
+    }
+
+    async fn send_request(&self, message: Vec<u8>) -> Result<oneshot::Receiver<ChannelReply>> {
+        let (reply_tx, reply_rx) = oneshot::channel();
+        let request = ChannelRequest { message, reply_tx };
+        self.sender.send(request).await.map_err(|_| Error::Eof)?;
+        Ok(reply_rx)
+    }
+
+    async fn get_reply(&self, reply_rx: oneshot::Receiver<ChannelReply>) -> Result<Vec<u8>> {
+        let reply = reply_rx.await.map_err(|_| Error::Eof)?;
+        Ok(reply.reply)
+    }
+}
diff --git a/broker/src/main.rs b/broker/src/main.rs
index 1cd2f7c..4830fff 100644
--- a/broker/src/main.rs
+++ b/broker/src/main.rs
@@ -1,12 +1,14 @@
 #![feature(once_cell)]
+mod chain_tracker;
 mod init;
 mod mqtt;
 mod run_test;
 mod unix_fd;
 mod util;
 
+use crate::chain_tracker::MqttSignerPort;
 use crate::mqtt::start_broker;
-use crate::unix_fd::{MqttSignerPort, SignerLoop};
+use crate::unix_fd::SignerLoop;
 use bitcoin::Network;
 use clap::{arg, App, AppSettings, Arg};
 use std::env;
diff --git a/broker/src/unix_fd.rs b/broker/src/unix_fd.rs
index e81fa55..4161fa5 100644
--- a/broker/src/unix_fd.rs
+++ b/broker/src/unix_fd.rs
@@ -1,13 +1,10 @@
 use crate::{Channel, ChannelReply, ChannelRequest};
-use async_trait::async_trait;
 use log::*;
 use secp256k1::PublicKey;
 use sphinx_key_parser as parser;
 use std::thread;
 use tokio::sync::{mpsc, oneshot};
-use tokio::task::spawn_blocking;
 use vls_protocol::{msgs, msgs::Message, Error, Result};
-use vls_protocol_client::SignerPort;
 use vls_proxy::client::Client;
 
 #[derive(Clone, Debug)]
@@ -134,42 +131,3 @@ impl<C: 'static + Client> SignerLoop<C> {
         Ok(reply.reply)
     }
 }
-
-pub struct MqttSignerPort {
-    sender: mpsc::Sender<ChannelRequest>,
-}
-
-#[async_trait]
-impl SignerPort for MqttSignerPort {
-    async fn handle_message(&self, message: Vec<u8>) -> Result<Vec<u8>> {
-        let reply_rx = self.send_request(message).await?;
-        self.get_reply(reply_rx).await
-    }
-
-    fn clone(&self) -> Box<dyn SignerPort> {
-        Box::new(Self {
-            sender: self.sender.clone(),
-        })
-    }
-}
-
-impl MqttSignerPort {
-    pub fn new(sender: mpsc::Sender<ChannelRequest>) -> Self {
-        Self { sender }
-    }
-
-    async fn send_request(&self, message: Vec<u8>) -> Result<oneshot::Receiver<ChannelReply>> {
-        let (reply_tx, reply_rx) = oneshot::channel();
-        let request = ChannelRequest { message, reply_tx };
-        self.sender.send(request).await.map_err(|_| Error::Eof)?;
-        Ok(reply_rx)
-    }
-
-    async fn get_reply(&self, reply_rx: oneshot::Receiver<ChannelReply>) -> Result<Vec<u8>> {
-        let reply = spawn_blocking(move || reply_rx.blocking_recv())
-            .await
-            .map_err(|_| Error::Eof)?
-            .map_err(|_| Error::Eof)?;
-        Ok(reply.reply)
-    }
-}