From e77ca735a07e851641067cbacf0ba61798511238 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mjumper@apache.org>
Date: Sat, 1 Sep 2018 14:35:01 -0700
Subject: [PATCH] GUACAMOLE-622: Increase size of instruction queue within
 FailoverGuacamoleSocket. Allow limit to be overridden.

Some protocols, in particular SSH and telnet, may send a decent amount
of data before the connection status is known.
---
 .../protocol/FailoverGuacamoleSocket.java     | 50 ++++++++++++++++---
 1 file changed, 42 insertions(+), 8 deletions(-)

diff --git a/guacamole-common/src/main/java/org/apache/guacamole/protocol/FailoverGuacamoleSocket.java b/guacamole-common/src/main/java/org/apache/guacamole/protocol/FailoverGuacamoleSocket.java
index 627c9fbad..3c64c51e7 100644
--- a/guacamole-common/src/main/java/org/apache/guacamole/protocol/FailoverGuacamoleSocket.java
+++ b/guacamole-common/src/main/java/org/apache/guacamole/protocol/FailoverGuacamoleSocket.java
@@ -49,11 +49,10 @@ public class FailoverGuacamoleSocket implements GuacamoleSocket {
             LoggerFactory.getLogger(FailoverGuacamoleSocket.class);
 
     /**
-     * The maximum number of characters of Guacamole instruction data to store
-     * within the instruction queue while searching for errors. Once this limit
-     * is exceeded, the connection is assumed to be successful.
+     * The default maximum number of characters of Guacamole instruction data
+     * to store if no explicit limit is provided.
      */
-    private static final int INSTRUCTION_QUEUE_LIMIT = 2048;
+    private static final int DEFAULT_INSTRUCTION_QUEUE_LIMIT = 131072;
 
     /**
      * The wrapped socket being used.
@@ -131,9 +130,11 @@ public class FailoverGuacamoleSocket implements GuacamoleSocket {
     /**
      * Creates a new FailoverGuacamoleSocket which reads Guacamole instructions
      * from the given socket, searching for errors from the upstream remote
-     * desktop. If an upstream error is encountered, it is thrown as a
+     * desktop until the given instruction queue limit is reached. If an
+     * upstream error is encountered, it is thrown as a
      * GuacamoleUpstreamException. This constructor will block until an error
-     * is encountered, or until the connection appears to have been successful.
+     * is encountered, until insufficient space remains in the instruction
+     * queue, or until the connection appears to have been successful.
      * Once the FailoverGuacamoleSocket has been created, all reads, writes,
      * etc. will be delegated to the provided socket.
      *
@@ -141,6 +142,11 @@ public class FailoverGuacamoleSocket implements GuacamoleSocket {
      *     The GuacamoleSocket of the Guacamole connection this
      *     FailoverGuacamoleSocket should handle.
      *
+     * @param instructionQueueLimit
+     *     The maximum number of characters of Guacamole instruction data to
+     *     store within the instruction queue while searching for errors. Once
+     *     this limit is exceeded, the connection is assumed to be successful.
+     *
      * @throws GuacamoleException
      *     If an error occurs while reading data from the provided socket.
      *
@@ -148,7 +154,8 @@ public class FailoverGuacamoleSocket implements GuacamoleSocket {
      *     If the connection to guacd succeeded, but an error occurred while
      *     connecting to the remote desktop.
      */
-    public FailoverGuacamoleSocket(GuacamoleSocket socket)
+    public FailoverGuacamoleSocket(GuacamoleSocket socket,
+            final int instructionQueueLimit)
             throws GuacamoleException, GuacamoleUpstreamException {
 
         int totalQueueSize = 0;
@@ -177,7 +184,7 @@ public class FailoverGuacamoleSocket implements GuacamoleSocket {
             // Otherwise, track total data parsed, and assume connection is
             // successful if no error encountered within reasonable space
             totalQueueSize += instruction.toString().length();
-            if (totalQueueSize >= INSTRUCTION_QUEUE_LIMIT)
+            if (totalQueueSize >= instructionQueueLimit)
                 break;
 
         }
@@ -186,6 +193,33 @@ public class FailoverGuacamoleSocket implements GuacamoleSocket {
 
     }
 
+    /**
+     * Creates a new FailoverGuacamoleSocket which reads Guacamole instructions
+     * from the given socket, searching for errors from the upstream remote
+     * desktop until a maximum of 128KB of instruction data has been queued. If
+     * an upstream error is encountered, it is thrown as a
+     * GuacamoleUpstreamException. This constructor will block until an error
+     * is encountered, until insufficient space remains in the instruction
+     * queue, or until the connection appears to have been successful.
+     * Once the FailoverGuacamoleSocket has been created, all reads, writes,
+     * etc. will be delegated to the provided socket.
+     *
+     * @param socket
+     *     The GuacamoleSocket of the Guacamole connection this
+     *     FailoverGuacamoleSocket should handle.
+     *
+     * @throws GuacamoleException
+     *     If an error occurs while reading data from the provided socket.
+     *
+     * @throws GuacamoleUpstreamException
+     *     If the connection to guacd succeeded, but an error occurred while
+     *     connecting to the remote desktop.
+     */
+    public FailoverGuacamoleSocket(GuacamoleSocket socket)
+            throws GuacamoleException, GuacamoleUpstreamException {
+        this(socket, DEFAULT_INSTRUCTION_QUEUE_LIMIT);
+    }
+
     /**
      * GuacamoleReader which reads instructions from the queue populated when
      * the FailoverGuacamoleSocket was constructed. Once the queue has been