From 05d9675d8513daef9caa7ac0fa99adfa66b92ef7 Mon Sep 17 00:00:00 2001
From: Nguyen Le Vu Long <vulongvn98@gmail.com>
Date: Mon, 18 Mar 2019 23:36:33 +0700
Subject: [PATCH] [JENKINS-50095] Update X-Remoting-Minimum-Version header in
 /tcpSlaveAgentListener

---
 core/src/main/java/hudson/TcpSlaveAgentListener.java   | 10 +++++++++-
 .../resources/hudson/TcpSlaveAgentListener/index.jelly |  2 ++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/hudson/TcpSlaveAgentListener.java b/core/src/main/java/hudson/TcpSlaveAgentListener.java
index bd2b8a158137..07f71b7575bb 100644
--- a/core/src/main/java/hudson/TcpSlaveAgentListener.java
+++ b/core/src/main/java/hudson/TcpSlaveAgentListener.java
@@ -33,6 +33,7 @@
 import javax.annotation.Nullable;
 
 import hudson.model.AperiodicWork;
+import hudson.util.VersionNumber;
 import jenkins.model.Jenkins;
 import jenkins.model.identity.InstanceIdentityProvider;
 import jenkins.security.stapler.StaplerAccessibleType;
@@ -153,6 +154,13 @@ public String getAgentProtocolNames() {
         return StringUtils.join(Jenkins.getInstance().getAgentProtocols(), ", ");
     }
 
+    /**
+     * Gets Remoting minimum supported version to prevent unsupported agents from connecting
+     */
+    public VersionNumber getRemotingMinimumVersion() {
+        return RemotingVersionInfo.getMinimumSupportedVersion();
+    }
+
     @Override
     public void run() {
         try {
@@ -304,7 +312,7 @@ private void respondHello(String header, Socket s) throws IOException {
                     o.write("Jenkins-Session: " + Jenkins.SESSION_HASH + "\r\n");
                     o.write("Client: " + s.getInetAddress().getHostAddress() + "\r\n");
                     o.write("Server: " + s.getLocalAddress().getHostAddress() + "\r\n");
-                    o.write("Remoting-Minimum-Version: " + RemotingVersionInfo.getMinimumSupportedVersion() + "\r\n");
+                    o.write("Remoting-Minimum-Version: " + getRemotingMinimumVersion() + "\r\n");
                     o.flush();
                     s.shutdownOutput();
                 } else {
diff --git a/core/src/main/resources/hudson/TcpSlaveAgentListener/index.jelly b/core/src/main/resources/hudson/TcpSlaveAgentListener/index.jelly
index 85471432ae05..879acdca5ad0 100644
--- a/core/src/main/resources/hudson/TcpSlaveAgentListener/index.jelly
+++ b/core/src/main/resources/hudson/TcpSlaveAgentListener/index.jelly
@@ -39,6 +39,8 @@ THE SOFTWARE.
   <st:header name="X-Instance-Identity" value="${app.tcpSlaveAgentListener.identityPublicKey}" />
   <!-- reduce the number of client connection attempts during protocol negotiation -->
   <st:header name="X-Jenkins-Agent-Protocols" value="${app.tcpSlaveAgentListener.agentProtocolNames}"/>
+  <!-- publish minimum supported version of remoting agent -->
+  <st:header name="X-Remoting-Minimum-Version" value="${app.tcpSlaveAgentListener.remotingMinimumVersion}"/>
 
   Jenkins
 </j:jelly>