From a0844e9499efc78c49e1b4869caf9edccf5cc59d Mon Sep 17 00:00:00 2001
From: Craig Perkins <cwperx@amazon.com>
Date: Fri, 18 Oct 2024 15:10:12 -0400
Subject: [PATCH] Respond to comments, update usages and update docstring

Signed-off-by: Craig Perkins <cwperx@amazon.com>
---
 .../netty4/ssl/SecureNetty4Transport.java     | 18 ++++++++++---
 .../SecureTransportSettingsProvider.java      | 26 ++++++++++++++++---
 2 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/ssl/SecureNetty4Transport.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/ssl/SecureNetty4Transport.java
index 8e2aa750dcd04..b9e1704a2e343 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/ssl/SecureNetty4Transport.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/ssl/SecureNetty4Transport.java
@@ -57,6 +57,7 @@
 import java.net.SocketAddress;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
+import java.util.Optional;
 
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandler;
@@ -142,9 +143,14 @@ public SSLServerChannelInitializer(String name) {
         protected void initChannel(Channel ch) throws Exception {
             super.initChannel(ch);
 
-            final boolean dualModeEnabled = secureTransportSettingsProvider.isDualModeEnabled(settings);
+            boolean dualModeEnabled = false;
+            Optional<SecureTransportSettingsProvider.SecureTransportParameters> parameters = secureTransportSettingsProvider.parameters(
+                settings
+            );
+            if (parameters.isPresent()) {
+                dualModeEnabled = parameters.get().dualModeEnabled();
+            }
             if (dualModeEnabled) {
-                logger.info("SSL Dual mode enabled, using port unification handler");
                 final ChannelHandler portUnificationHandler = new DualModeSslHandler(
                     settings,
                     secureTransportSettingsProvider,
@@ -258,7 +264,13 @@ protected class SSLClientChannelInitializer extends Netty4Transport.ClientChanne
         public SSLClientChannelInitializer(DiscoveryNode node) {
             this.node = node;
 
-            final boolean dualModeEnabled = secureTransportSettingsProvider.isDualModeEnabled(settings);
+            boolean dualModeEnabled = false;
+            Optional<SecureTransportSettingsProvider.SecureTransportParameters> parameters = secureTransportSettingsProvider.parameters(
+                settings
+            );
+            if (parameters.isPresent()) {
+                dualModeEnabled = parameters.get().dualModeEnabled();
+            }
             hostnameVerificationEnabled = NetworkModule.TRANSPORT_SSL_ENFORCE_HOSTNAME_VERIFICATION.get(settings);
             hostnameVerificationResolveHostName = NetworkModule.TRANSPORT_SSL_ENFORCE_HOSTNAME_VERIFICATION_RESOLVE_HOST_NAME.get(settings);
 
diff --git a/server/src/main/java/org/opensearch/plugins/SecureTransportSettingsProvider.java b/server/src/main/java/org/opensearch/plugins/SecureTransportSettingsProvider.java
index df3258a1c7648..50fc6e98a1114 100644
--- a/server/src/main/java/org/opensearch/plugins/SecureTransportSettingsProvider.java
+++ b/server/src/main/java/org/opensearch/plugins/SecureTransportSettingsProvider.java
@@ -38,12 +38,30 @@ default Collection<TransportAdapterProvider<Transport>> getTransportAdapterProvi
     }
 
     /**
-     * Returns true if dual mode is enabled. Dual mode domains support both encrypted and non-encrypted traffic
+     * Returns parameters that can be dynamically provided by a plugin providing a {@link SecureTransportSettingsProvider}
+     * implementation
      * @param settings settings
-     * @return a boolean indicating if dual mode is enabled
+     * @return an instance of {@link SecureTransportParameters}
      */
-    default boolean isDualModeEnabled(Settings settings) {
-        return NetworkModule.TRANSPORT_SSL_DUAL_MODE_ENABLED.get(settings);
+    default Optional<SecureTransportParameters> parameters(Settings settings) {
+        return Optional.of(new DefaultSecureTransportParameters(settings));
+    }
+
+    interface SecureTransportParameters {
+        boolean dualModeEnabled();
+    }
+
+    class DefaultSecureTransportParameters implements SecureTransportParameters {
+        private final Settings settings;
+
+        DefaultSecureTransportParameters(Settings settings) {
+            this.settings = settings;
+        }
+
+        @Override
+        public boolean dualModeEnabled() {
+            return NetworkModule.TRANSPORT_SSL_DUAL_MODE_ENABLED.get(settings);
+        }
     }
 
     /**