Proxy ProtocolsSOCKS 4, 4a, and 5Advanced Software Engineering (CSE870)Instructor: Dr. B. ChengContact info: chengb at cse dot msu dot edu

Kayra HopkinsLoretta Macklem

Outline

? Introduction?Frameworks?Demo?Extra Credit Implementation?Demo

Introduction

?SOCKS - an Internet protocol that allows client-server applications to transparently use the services of a network.

SOCKS Protocols

? SOCKS 4– No authentication– Simple connect and bind connections supported

? SOCKS 4a– Domain resolution

? SOCKS 5– Authentication plus UDP connection supported

Frameworks

?Framework - a reusable design for a software system expressed as

– Set of abstract classes

– The way their instances collaborate for a specific type of software

Use of Frameworks for SOCKS

?SOCKS versions have a large amount of common functionality

?First step was to identify all major common functionality.

Whitebox? Commonalities

– Identify if client or server can access IP requested– Creating a connection to a server – Receiving messages– Forwarding messages – Sending reply messages– Authentication

? Differences (points of extension)– Parsing the request message – Forming the reply message – Creating new types of authentication

Whitebox, cont.

?Design Pattern

– Iterator Pattern

• Username/Password Login

• Domain Resolution

• Authentication

Whitebox Class Diagram

Magenta is Design Pattern, Green is where user implements functionality, Blue is abstract class

Greybox

?Changes– Authentication is now an interface– At the time only one protocol used

authentication so we thought it would be the easiest to change for greybox

Red is interfaces, Magenta is Design Pattern, Green is where user implements functionality, Blue is abstract class

Blackbox

?All extension are done through interfaces

Red is interfaces, Magenta is Design Pattern, Green is where user implements functionality

State Diagram

Connected Connection Denied

Demo

Problems We Encountered

? Figuring out how to get the information from the request messages without having the control loop be changed much

? Solution - have implementation of parsing the request message have a function which returns an array with all of the needed values to be passed to reply message implementation

What We Learned

?No comment on whether making a whitebox is easier than making a blackbox

?Able to identify where we have used frameworks previously without knowing it

Applying Our Framework to MISys

?Decided to place all patient records on a separate server, apart from the application

?MISys uses proxy to connect to other server and obtain patient information

Class Diagram

MISys

SOCKS Framework

Framework accesses Patient or Appointment Records

Makes call to obtain Patient or Appt Records

Connects to Iterator Class

Connects to MISysMainUI class

MISys Demo

Questions?