From f7fb54dc8a7a119fa360d32f45d62a94fea042a9 Mon Sep 17 00:00:00 2001
From: Matthew Nesbit <matthew.nesbit@r3.com>
Date: Wed, 16 May 2018 16:00:41 +0100
Subject: [PATCH] Detect duplicate bridge operation and terminate JVM to
 prevent re-ordering flow messages and causing odd behaviour.

---
 .../bridging/BridgeControlListener.kt         | 42 +++++++++++++++++--
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/node-api/src/main/kotlin/net/corda/nodeapi/internal/bridging/BridgeControlListener.kt b/node-api/src/main/kotlin/net/corda/nodeapi/internal/bridging/BridgeControlListener.kt
index 6d49eee754..cddfcfaeae 100644
--- a/node-api/src/main/kotlin/net/corda/nodeapi/internal/bridging/BridgeControlListener.kt
+++ b/node-api/src/main/kotlin/net/corda/nodeapi/internal/bridging/BridgeControlListener.kt
@@ -28,6 +28,7 @@ import org.apache.activemq.artemis.api.core.RoutingType
 import org.apache.activemq.artemis.api.core.SimpleString
 import org.apache.activemq.artemis.api.core.client.ClientConsumer
 import org.apache.activemq.artemis.api.core.client.ClientMessage
+import org.apache.activemq.artemis.api.core.client.ClientSession
 import rx.Observable
 import rx.subjects.PublishSubject
 import java.util.*
@@ -39,11 +40,13 @@ class BridgeControlListener(val config: NodeSSLConfiguration,
                             val artemisMessageClientFactory: () -> ArtemisSessionProvider) : AutoCloseable {
     private val bridgeId: String = UUID.randomUUID().toString()
     private val bridgeControlQueue = "$BRIDGE_CONTROL.$bridgeId"
+    private val bridgeNotifyQueue = "$BRIDGE_NOTIFY.$bridgeId"
     private val bridgeManager: BridgeManager = AMQPBridgeManager(config, socksProxyConfig, maxMessageSize,
             artemisMessageClientFactory)
     private val validInboundQueues = mutableSetOf<String>()
     private var artemis: ArtemisSessionProvider? = null
     private var controlConsumer: ClientConsumer? = null
+    private var notifyConsumer: ClientConsumer? = null
 
     constructor(config: NodeSSLConfiguration,
                 p2pAddress: NetworkHostAndPort,
@@ -71,11 +74,21 @@ class BridgeControlListener(val config: NodeSSLConfiguration,
         artemis.start()
         val artemisClient = artemis.started!!
         val artemisSession = artemisClient.session
+        registerBridgeControlListener(artemisSession)
+        registerBridgeDuplicateChecker(artemisSession)
+        val startupMessage = BridgeControl.BridgeToNodeSnapshotRequest(bridgeId).serialize(context = SerializationDefaults.P2P_CONTEXT).bytes
+        val bridgeRequest = artemisSession.createMessage(false)
+        bridgeRequest.writeBodyBufferBytes(startupMessage)
+        artemisClient.producer.send(BRIDGE_NOTIFY, bridgeRequest)
+    }
+
+    private fun registerBridgeControlListener(artemisSession: ClientSession) {
         try {
             artemisSession.createTemporaryQueue(BRIDGE_CONTROL, RoutingType.MULTICAST, bridgeControlQueue)
         } catch (ex: ActiveMQQueueExistsException) {
             // Ignore if there is a queue still not cleaned up
         }
+
         val control = artemisSession.createConsumer(bridgeControlQueue)
         controlConsumer = control
         control.setMessageHandler { msg ->
@@ -85,10 +98,28 @@ class BridgeControlListener(val config: NodeSSLConfiguration,
                 log.error("Unable to process bridge control message", ex)
             }
         }
-        val startupMessage = BridgeControl.BridgeToNodeSnapshotRequest(bridgeId).serialize(context = SerializationDefaults.P2P_CONTEXT).bytes
-        val bridgeRequest = artemisSession.createMessage(false)
-        bridgeRequest.writeBodyBufferBytes(startupMessage)
-        artemisClient.producer.send(BRIDGE_NOTIFY, bridgeRequest)
+    }
+
+    private fun registerBridgeDuplicateChecker(artemisSession: ClientSession) {
+        try {
+            artemisSession.createTemporaryQueue(BRIDGE_NOTIFY, RoutingType.MULTICAST, bridgeNotifyQueue)
+        } catch (ex: ActiveMQQueueExistsException) {
+            // Ignore if there is a queue still not cleaned up
+        }
+        val notify = artemisSession.createConsumer(bridgeNotifyQueue)
+        notifyConsumer = notify
+        notify.setMessageHandler { msg ->
+            try {
+                val data: ByteArray = ByteArray(msg.bodySize).apply { msg.bodyBuffer.readBytes(this) }
+                val notifyMessage = data.deserialize<BridgeControl.BridgeToNodeSnapshotRequest>(context = SerializationDefaults.P2P_CONTEXT)
+                if (notifyMessage.bridgeIdentity != bridgeId) {
+                    log.error("Fatal Error! Two bridges have been configured simultaneously! Check the enterpriseConfiguration.externalBridge status")
+                    System.exit(1)
+                }
+            } catch (ex: Exception) {
+                log.error("Unable to process bridge notification message", ex)
+            }
+        }
     }
 
     fun stop() {
@@ -98,8 +129,11 @@ class BridgeControlListener(val config: NodeSSLConfiguration,
         validInboundQueues.clear()
         controlConsumer?.close()
         controlConsumer = null
+        notifyConsumer?.close()
+        notifyConsumer = null
         artemis?.apply {
             started?.session?.deleteQueue(bridgeControlQueue)
+            started?.session?.deleteQueue(bridgeNotifyQueue)
             stop()
         }
         artemis = null