Fix TCP-search bug in server and client

src/core/com/cosylab/epics/caj/cas/handlers/SearchResponse.java

@@ -138,14 +138,16 @@ private void searchResponse(InetSocketAddress responseFrom, CASTransport tcp, sh
 			try
 			{
 				// TODO prepend version header (if context.getLastReceivedSequenceNumber() != 0)
-				SearchRequest searchRequest = new SearchRequest(context.getBroadcastTransport(), (short)dataCount, cid);
+				// UDP includes payload (version) in reply, TCP has no payload
 				if (tcp == null)
 				{
+					SearchRequest searchRequest = new SearchRequest(context.getBroadcastTransport(), null, true, (short)dataCount, cid);
 					context.getLogger().log(Level.FINE, "UDP EXISTS_HERE search reply");
 					context.getBroadcastTransport().send(searchRequest, responseFrom);
 				}
 				else
 				{
+					SearchRequest searchRequest = new SearchRequest(context.getBroadcastTransport(), null, false, (short)dataCount, cid);
 					context.getLogger().log(Level.FINE, "TCP EXISTS_HERE search reply");
 				    tcp.send(searchRequest.getRequestMessage());
 				}
@@ -155,18 +157,18 @@ private void searchResponse(InetSocketAddress responseFrom, CASTransport tcp, sh
 		}
 		else if (completion.doesExistElsewhere())
 		{
-			// send back
+			// Same comments as for EXISTS_HERE
 			try
 			{
-				// TODO prepend version header (if context.getLastReceivedSequenceNumber() != 0)
-				SearchRequest searchRequest = new SearchRequest(context.getBroadcastTransport(), completion.getOtherAddress(), (short)dataCount, cid);
 				if (tcp == null)
 				{
+					SearchRequest searchRequest = new SearchRequest(context.getBroadcastTransport(), completion.getOtherAddress(), true, (short)dataCount, cid);
 					context.getLogger().log(Level.FINE, "UDP EXISTS_ELSEWHERE search reply: " + completion.getOtherAddress());
 					context.getBroadcastTransport().send(searchRequest, responseFrom);
 				}
 				else
 				{
+					SearchRequest searchRequest = new SearchRequest(context.getBroadcastTransport(), completion.getOtherAddress(), false, (short)dataCount, cid);
 					context.getLogger().log(Level.FINE, "TCP EXISTS_ELSEWHERE search reply: " + completion.getOtherAddress());
 				    tcp.send(searchRequest.getRequestMessage());
 				}

src/core/com/cosylab/epics/caj/cas/requests/SearchRequest.java

@@ -36,23 +36,14 @@ public class SearchRequest extends AbstractCARequest {
 
 	private static final Logger logger = Logger.getLogger(SearchRequest.class.getName());
 
-	/**
-	 * @param transport Transport to use
-	 * @param clientMinorVersion
-	 * @param cid Channel ID
-	 */
-	public SearchRequest(Transport transport, short clientMinorVersion, int cid)
-	{
-		this(transport, null, clientMinorVersion, cid);
-	}
-
 	/**
 	 * @param transport Transport to use
 	 * @param other_address Optional other address to report, null to use this transport
+	 * @param with_version Include minor version in payload (for UDP), or no payload (for TCP)?
 	 * @param clientMinorVersion
 	 * @param cid Channel ID
 	 */
-	public SearchRequest(Transport transport, InetSocketAddress other_address, short clientMinorVersion, int cid) {
+	public SearchRequest(Transport transport, InetSocketAddress other_address, boolean with_version, short clientMinorVersion, int cid) {
 		super(transport);
 
 		// add minor version payload (aligned by 8)
@@ -72,17 +63,20 @@ public SearchRequest(Transport transport, InetSocketAddress other_address, short
 									  : other_address.getAddress();
 			if (serverAddress != null && !serverAddress.isAnyLocalAddress())
 				serverIP = InetAddressUtil.ipv4AddressToInt(serverAddress);
-			logger.log(Level.FINE, "Replying to search with " + serverAddress + ":" + port);
 		}
 
 		requestMessage = insertCAHeader(transport, requestMessage,
-										(short)6, (short)8, (short)port, 0,
+										(short)6, (short)(with_version ? 8 : 0), (short)port, 0,
 										serverIP, cid);
-
-		requestMessage.putShort(CAConstants.CAS_MINOR_PROTOCOL_REVISION);
-		// clear rest of the message (security)
-		requestMessage.putShort((short)0);
-		requestMessage.putInt(0);
+		if (with_version)
+		{
+			requestMessage.putShort(CAConstants.CAS_MINOR_PROTOCOL_REVISION);
+			// clear rest of the message (security)
+			requestMessage.putShort((short)0);
+			requestMessage.putInt(0);
+			logger.log(Level.FINE, "Replying to search with " + serverIP + ":" + port + ", minor " + CAConstants.CAS_MINOR_PROTOCOL_REVISION);
+		}
+		logger.log(Level.FINE, "Replying to search with " + serverIP + ":" + port + ", no payload");
 	}
 
 	/**

src/core/com/cosylab/epics/caj/impl/handlers/SearchResponse.java

@@ -25,6 +25,7 @@
 import com.cosylab.epics.caj.impl.CATransport;
 import com.cosylab.epics.caj.impl.Transport;
 import com.cosylab.epics.caj.util.InetAddressUtil;
+import com.cosylab.epics.caj.util.HexDump;
 
 /**
  * @author <a href="mailto:matej.sekoranjaATcosylab.com">Matej Sekoranja</a>
@@ -53,21 +54,69 @@ protected void internalHandleResponse(
 		//
 
 		short minorVersion = CAConstants.CA_UNKNOWN_MINOR_PROTOCOL_REVISION;
+
+		// Search response via UDP: Only response[0]
+		// Payload size 8, with only a 'short minor' in payload
+		//
+		// Hexdump [response[0] @ 16] size = 24
+		// 00 06 00 08  13 C8 00 00  FF FF FF FF  00 00 00 01  .... .... .... .... 
+		// 00 0B 00 00  00 00 00 00 
+		// or
+		// Hexdump [response[0] @ 32] size = 40
+		// 00 00 00 00  00 01 00 0D  00 00 00 01  00 00 00 00  .... .... .... .... 
+		// 00 06 00 08  13 C8 00 00  FF FF FF FF  00 00 00 01  .... .... .... .... 
+		// 00 0D 00 00  00 00 00 00                            .... .... 
+
+		// Search response via TCP: Two buffers
+		// No payload, second buffer is empty
+		//
+		// Hexdump [response[0] @ 16] size = 16
+		// 00 06 00 00  13 C8 00 00  FF FF FF FF  00 00 00 01  .... .... .... .... 
+		// Hexdump [response[1] @ 0] size = 0
+
+		// Earlier CAJ server server added the 8 byte payload to TCP response,
+		// which caused client to crash.
+		// Now handle that as well in client.
+		// Hexdump [response[0] @ 16] size = 16
+		// 00 06 00 08  13 C8 00 00  FF FF FF FF  00 00 00 01  .... .... .... .... 
+		// Hexdump [response[1] @ 0] size = 8
+		// 00 0B 00 00  00 00 00 00     
+
+		// System.out.println("Client received search response");
+		// System.out.println(response[0]);
+		// if (response.length > 1)
+		// 	System.out.println(response[1]);
+		//
+		// byte[] data = new byte[response[0].limit()];
+		// for (int i=0; i<response[0].limit(); ++i)
+		// 	data[i] = response[0].get(i);
+		// HexDump.hexDump("response[0] @ " + response[0].position(), data, 0, response[0].limit());
+		// if (response.length > 1)
+		// {
+		// 	data = new byte[response[1].limit()];
+		// 	for (int i=0; i<response[1].limit(); ++i)
+		// 		data[i] = response[1].get(i);
+		// 	HexDump.hexDump("response[1] @ " + response[1].position(), data, 0, response[1].limit());
+		// }
 
 		// Starting with CA V4.1 the minor version number is
 		// appended to the end of each search reply.
 		int payloadStart = response[0].position();
 		if (payloadSize >= 2 /* short size = 2 bytes */)
 		{ 
-			// UDP response (all in buffer 0)
-			minorVersion = response[0].getShort();
+			// UDP response (all in buffer 0), or TCP (payload in buffer 1)?
+			if (response.length == 1)
+				minorVersion = response[0].getShort();
+			else
+				minorVersion = response[1].getShort();
 		} else if(transport instanceof CATransport) {
 			// for TCP transport use already provided version
 			minorVersion = transport.getMinorRevision();
 		}
 
 		// read rest of the playload (needed for UDP)
-		response[0].position(payloadStart + payloadSize);
+		if (response.length == 1)
+			response[0].position(payloadStart + payloadSize);
 
 		// signed short conversion -> signed int 
 		int port = dataType & 0xFFFF;

test/com/cosylab/epics/caj/cas/test/CANameServer.java

@@ -42,6 +42,7 @@
  *  via UDP port 5064, while the IOC runs on 9876 (UDP and TCP).
  * 
  *  Now run this CANameServer on the same host,
+ *      java -cp target/classes:target/test-classes -DCAJ_DEBUG=true com.cosylab.epics.caj.cas.test.CANameServer
  *  and try `caget ramp` again.
  *  The client will reach the name server via UDP 5064.
  *  The name server replies with 127.0.0.1, port 9876

test/com/cosylab/epics/caj/test/caget.java

@@ -0,0 +1,48 @@
+package com.cosylab.epics.caj.test;
+
+import gov.aps.jca.JCALibrary;
+import gov.aps.jca.Context;
+import com.cosylab.epics.caj.CAJContext;
+import gov.aps.jca.Channel;
+import gov.aps.jca.dbr.DBR;
+import gov.aps.jca.dbr.DBRType;
+import gov.aps.jca.dbr.DBR_Double;
+
+/** Bad but simple 'caget' demo
+ *  Better implementation would use listeners
+ *  instead of fixed wait times,
+ *  handle all data types,
+ *  and properly close channel and context.
+ * 
+ *  Example invocation:
+ *  java -cp target/classes:target/test-classes -DCAJ_DEBUG=true -Djca.use_env=true com.cosylab.epics.caj.test.caget PV_name
+ */
+public class caget
+{
+    public static void main(String[] args) throws Exception
+    {
+        if (args.length != 1)
+        {
+            System.err.println("USAGE: caget PV_name");
+            System.exit(1);
+        }
+        final String name = args[0];
+
+        final JCALibrary jca = JCALibrary.getInstance();
+        final Context context = new CAJContext();
+        final Channel channel = context.createChannel(name);
+        context.pendIO(2.0);
+
+        DBR data = channel.get(DBRType.DOUBLE, 1);
+        context.pendIO(2.0);
+
+        if (data instanceof DBR_Double)
+        {
+            DBR_Double value = (DBR_Double) data;
+            System.out.println(name + " = " + value.getDoubleValue()[0]);
+        }
+        else
+            System.out.println(data);
+        System.exit(0);
+    }
+}

test/resources/ramp.db

@@ -0,0 +1,6 @@
+record(calc, "ramp")
+{
+  field(SCAN, "1 second")
+  field(CALC, "A+1")
+  field(INPA, "ramp")
+}