Adding upstream version 4.2.2.upstream/4.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 86 insertions, 0 deletions

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+OpcUa Plugin:
+=============
+
+This plugin implements the dissection of the OpcUa Binary Protocol.
+Authors: Gerhard Gappmeier & Hannes Mezger
+         ascolab GmbH
+         http://www.ascolab.com
+	
+Overview:
+=========
+
+OpcUa (OPC Unified Architecture) is a vendor and platform independent
+protocol for automation technology. It is the successor of the
+COM/DCOM based specifications OPC DA, OPC Alarm & Events, OPC HDA, etc.
+It unifies all this technologies into a single protocol.
+
+The specification describes abstract services that are independent
+of the underlying protocol. For now there exist protocol mappings
+to a Binary TCP based protocol and a SOAP based Webservice.
+Also a hybrid version will be available where the Binary messages are transported
+by a single webservice command called "Invoke".
+
+More information about the technology you can find on
+http://www.ascolab.com/index.php?file=ua&lang=en.
+
+Protocol Mappings:
+==================
+
+Binary (TCP): The fastest and most flexible version (small footprint, no XML and SOAP necessary)
+              can easily be tunneled (SSH, IPSEC, etc.), redirected, ...
+SOAP version: Easy to implement with verious tools like .Net, JAVA, gSOAP, etc.
+              Better to communicate through firewalls via HTTP.
+SOAP with Binary Attachment: Combines the advantages of both.
+              The messages are encoded as Binary, and transported via SOAP as binary
+              attachment.
+
+The OPC Foundation offers a free Opc Ua stack implementation in ANSI C
+for all members. This stack implements the binary protocol as well
+as the SOAP version. It's easily portable to different kinds of operating
+systems from embedded devices to servers.
+This makes it easy to implement Opc Ua applications based on this stack
+and it is expected that the binary protocol will be the most used
+protocol.
+Nevertheless it's free to everbody to implement an own stack according
+to the specification. An own implementation of the SOAP version 
+should be easy with the various SOAP toolkits.
+
+For more information see http://www.opcfoundation.org
+
+Known limitations:
+==================
+
+* Only the security policy http://opcfoundation.org/UA/SecurityPolicy#None is
+  supported, which means the encryption and signing is turned off.
+  
+Machine-generated dissector:
+============================
+Parts of the OpcUa dissector are machine generated.  Several of the files are
+marked "DON'T MODIFY THIS FILE!" for this reason.
+
+However, the code to create this dissector is not part of the Wireshark source
+source code distribution.  This was discussed prior to the plugin's inclusion.
+From https://www.wireshark.org/lists/wireshark-dev/200704/msg00025.html :
+
+~~~
+> a lot of the code seems to be autogenerated (as the comments suggest)
+> It might make sense to include the sources and the build process instead 
+> of the intermediate files (if the amount of code/tools to build the 
+> files seems reasonable). The reason: When people start to hack your code 
+> (e.g. to remove warnings on a compiler you don't even think about), 
+> you'll might get into annoying trouble with merging code the next time 
+> you've update the upcua files.
+>
+>   
+I'm sorry, but I cannot give you the sources of the code generator,
+because they are owned by the OPC Foundation.
+I only extended the existing code generator to produce also wireshark code.
+It's .Net based so I guess you don't want to have it anyway ;-)
+~~~
+
+So, if changes must be made to the machine-generated files, it just means the
+upstream source will have to be modified before pushing any updates back to
+Wireshark.
+
+Of course it also means that care must be taken when applying patches from
+upstream to ensure local changes aren't reversed.