Merge branch 'cassandra-3.9' into trunk

CHANGES.txt

@@ -18,6 +18,8 @@
  * cqlsh: Fix handling of $$-escaped strings (CASSANDRA-12189)
  * Fix SSL JMX requiring truststore containing server cert (CASSANDRA-12109)
 Merged from 3.0:
+ * Respond with v1/v2 protocol header when responding to driver that attempts
+   to connect with too low of a protocol version (CASSANDRA-11464)
  * NullPointerExpception when reading/compacting table (CASSANDRA-11988)
  * Fix problem with undeleteable rows on upgrade to new sstable format (CASSANDRA-12144)
 Merged from 2.2:

src/java/org/apache/cassandra/transport/Frame.java

@@ -176,7 +176,8 @@ public class Frame
             int version = firstByte & PROTOCOL_VERSION_MASK;
             if (version < Server.MIN_SUPPORTED_VERSION || version > Server.CURRENT_VERSION)
                 throw new ProtocolException(String.format("Invalid or unsupported protocol version (%d); the lowest supported version is %d and the greatest is %d",
-                                                          version, Server.MIN_SUPPORTED_VERSION, Server.CURRENT_VERSION));
+                                                          version, Server.MIN_SUPPORTED_VERSION, Server.CURRENT_VERSION),
+                                            version);
 
             // Wait until we have the complete header
             if (readableBytes < Header.LENGTH)
@@ -275,6 +276,8 @@ public class Frame
             header.writeByte(type.direction.addToVersion(frame.header.version));
             header.writeByte(Header.Flag.serialize(frame.header.flags));
 
+            // Continue to support writing pre-v3 headers so that we can give proper error messages to drivers that
+            // connect with the v1/v2 protocol. See CASSANDRA-11464.
             if (frame.header.version >= Server.VERSION_3)
                 header.writeShort(frame.header.streamId);
             else

src/java/org/apache/cassandra/transport/Message.java

@@ -150,6 +150,7 @@ public abstract class Message
     private int streamId;
     private Frame sourceFrame;
     private Map<String, ByteBuffer> customPayload;
+    protected Integer forcedProtocolVersion = null;
 
     protected Message(Type type)
     {
@@ -389,7 +390,12 @@ public abstract class Message
                     throw e;
                 }
 
-                results.add(Frame.create(message.type, message.getStreamId(), version, flags, body));
+                // if the driver attempted to connect with a protocol version lower than the minimum supported
+                // version, respond with a protocol error message with the correct frame header for that version
+                int responseVersion = message.forcedProtocolVersion == null
+                                    ? version
+                                    : message.forcedProtocolVersion;
+                results.add(Frame.create(message.type, message.getStreamId(), responseVersion, flags, body));
             }
             catch (Throwable e)
             {

src/java/org/apache/cassandra/transport/ProtocolException.java

@@ -25,13 +25,31 @@ import org.apache.cassandra.exceptions.TransportException;
  */
 public class ProtocolException extends RuntimeException implements TransportException
 {
+    private final Integer attemptedLowProtocolVersion;
+
     public ProtocolException(String msg)
+    {
+        this(msg, null);
+    }
+
+    public ProtocolException(String msg, Integer attemptedLowProtocolVersion)
     {
         super(msg);
+        this.attemptedLowProtocolVersion = attemptedLowProtocolVersion;
     }
 
     public ExceptionCode code()
     {
         return ExceptionCode.PROTOCOL_ERROR;
     }
+
+    /**
+     * If the ProtocolException is due to a connection being made with a protocol version that is lower
+     * than Server.MIN_SUPPORTED_VERSION, this will return that unsupported protocol version.  Otherwise,
+     * null is returned.
+     */
+    public Integer getAttemptedLowProtocolVersion()
+    {
+        return attemptedLowProtocolVersion;
+    }
 }

src/java/org/apache/cassandra/transport/messages/ErrorMessage.java

@@ -331,7 +331,18 @@ public class ErrorMessage extends Message.Response
         }
 
         if (e instanceof TransportException)
-            return new ErrorMessage((TransportException)e, streamId);
+        {
+            ErrorMessage message = new ErrorMessage((TransportException) e, streamId);
+            if (e instanceof ProtocolException)
+            {
+                // if the driver attempted to connect with a protocol version lower than the minimum supported
+                // version, respond with a protocol error message with the correct frame header for that version
+                Integer attemptedLowProtocolVersion = ((ProtocolException) e).getAttemptedLowProtocolVersion();
+                if (attemptedLowProtocolVersion != null)
+                    message.forcedProtocolVersion = attemptedLowProtocolVersion;
+            }
+            return message;
+        }
 
         // Unexpected exception
         if (unexpectedExceptionHandler == null || !unexpectedExceptionHandler.apply(e))