Seagull code documentation

Go back to user documentation: http://gull.sf.net/doc/

Introduction

The purpose of this documentation is to explain Seagull interns. It is a summary to help developers make their way through Seagull and start contributing.

Main modules

• C_Generator: core of Seagull. Contains the main functions.
• C_TrafficModel: internal model of Seagull to control the way new scenarios are created.
• C_CallContext: Management of the call context
• C_CallControl: Management of the calls. Pause, restart traffic, set call rate...
• C_ReadControl: Takes care of reading the protocol events, keyboard events and associated scheduling.
• generator-scenario: C_ScenarioControl provides methods relating to the execution of the scenario. C_Scenario takes care of reading and interpreting scenarios.
• ProtocolData.cpp: definition of generic data types (string, number, number64, ...) used by Seagull, as well as associated operator overloads.
• C_ProtocolFrame: virtual definition of a protocol and its messages. It contains the only objects that will be used by the generator
• C_Transport: generic definition of a transport
• C_CommandAction: Class from which derives all classes implementing an action. Start here if you want to add one.
• C_DisplayObject: Class that displays various screens (statistics, help, traffic, ...)

Other modules

• common directory: contains all the .h files to adapt some system includes to the target compilation platform
• C_DataLogRTDistrib: deals with response time logs (csv file)
• exe-env directory: execution environment for each protocol
• C_ExternalDataControl: manage external data files, to insert data into scenario messages during the call
• generator-common: utils for the tool (buffer management, id, ...)
• C_TransIP: IP v4 & v6 transport transport; daughter class of C_Transport
• C_TransSCTP: SCTP transport library; daughter class of C_Transport
• C_TransIPTLS: TLS transport; daughter class of C_TransIP
• C_TransOCTcap32: OpenCall TCAP API transport; daughter class of C_Transport
• C_ProtocolBinary: binary protocol definition (e.g. Diameter); daughter class of C_ProtocolBinaryFrame, C_MessageFrame
• statistics: stats management
• C_XmlData and C_XmlParser to parse the xml files (dictionary, scenario and configuration file)

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”)*> <>)*
• 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.

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