Developer documentation

The purpose of this documentation is to explain Seagull interns. It is a summary to help developers make their way through Seagull and not intended to be a definitive developer documentation.

Main modules

• generator-core: core of Seagull. Contains the main functions.
• generator-model: internal model of Seagull to manage protocols, channels and transports.
• generator-scenario: model for the scenario
• generator-traffic: traffic model. Management of the call context, of the read/write on transport channel, of the execution of the calls.
• protocol-data: definition of generic data used by the generator
• protocol-frame: virtual definition of a protocol and its messages. It contains the only objects that will be used by the generator
• transport-frame: generic definition of a transport

Other modules

• common: contains all the .h files to adapt some system includes to the target compilation platform
• data-log: deals with response time logs (csv file)
• exe-env: execution environment for each protocol
• external-data: manage external data files, to insert data into scenario messages during the call
• generator-common: utils for the tool (buffer management, id, ...)
• library-trans-extsctp: SCTP transport library; daughter class of C_Transport
• library-trans-ip: IP v4 & v6 transport transport; daughter class of C_Transport
• protocol-binary: binary protocol definition (e.g. Diameter); daughter class of C_ProtocolBinaryFrame, C_MessageFrame
• statistics: stats management
• xml-parser: parsing the xml files (dictionary, scenario and configuration file)

Main objects

• C_Generator (module generator-core): Main object
• C_ReadControl (module generator-traffic)
• C_CallControl (module generator-traffic): Objects for the execution of the scenario
• Protocol objects:
  
  
• C_ProtocolControl (module generator-model): The only object that knows about the non-virtual message and protocol objects.

Threads

There are 5 threads in Seagull:

• One thread that handles the whole traffic,
• One thread for the keyboard,
• One thread for the tool display,
• One thread for the logs,
• One thread for the statistics.

They are handled in generator-core module

Protocol and messages

• To implement a text protocol, you need to create a new implementation of C_ProtocolFrame and C_MessageFrame like C_ProtocolBinary and C_MessageBinary
• In those classes, you implement the management of the XML tags and the protocol definition
• You need to add them in C_ProtocolControl to be instantiated by the tool

XML parsing

• Handled in module xml-parser
• XML files are parsed by C_XmlParser
• XML data are represented as a tree of elements (based on stl types): (<TAG (FIELD=“VALUE”)*> <\TAG>)*
• Useful functions in C_XmlData allows to get the name of a tag, retrieve the value of a field or the list (stl) of element under one element.

Channel creation

• C_TransIP (module library-trans-ip) implements the transport, based on virtual object C_Transport (module transport-frame)
• Done/Declared in conf file.
• Channel = link between one protocol and one transport, with an open command for the transport

Multi-channel policy

Automatic session based: possible to open several channels (using same or different protocols), but only the first channel used can be server.