WebPad Management Protocol

1
WebPad Management Protocol

• D87526013 ???
• B87506017 ???

2
Motivation

• Homework -P
• Management issues for mobile or wide-spread
  devices

3
Working Environment

• Server side
• Central controlling Server on Win32
• Monitor all the client directly
• Client Side
• A client app running on mobile WebPad
• Browser on WebPad must co-operate with the client
  app
• Browser ask the client app for access/deny list

4
Design Criteria

• Feasible for mobile/low-power devices
• Not depending on other mechanisms
• Really help for MIS team
• Easy to implement maintain
• Combining existing/popular applications helping
  for management

5
Why Not SNMP?

• Not really simple
• ASN.1
• Database (MIB) required
• Security issues

6
For MIS Point of View

• Collecting information from thin-client machines
• Maintaining consistency and availability among
  clients
• Offering online/real-time communication with users

7
Demands

• Status report
• Shell commands
• Access list for Web Browser
• Message alert
• Online update
• ICA/VNC server
• Reset
• Security

8
Protocol Design

• Manager v.s. Agent
• TCP/UDP port 6147
• Current implementation based on UDP.
• Session continuation
• Packet formats
• Readable Text/ Easy debugging

9
Commands Responses

• Commands format
• AGENT ltagentidgt command paramater...
• MANAGER ltmanageridgt command paramater...
• keyword FOLLOWING indicates line continuation
• Responses format
• ltreply codegt reply string
• reply code is a 3 digit number, while reply
  string contains information for advanced parsing

10
Negotiation

• Registration
• User login
• Communication security
• Server force client to UNREG or LOGOUT
• Server migration due to failure
• Directly give command to client by MIS for
  special case ...
• Timeout policy
• 3 rounds of push 1 round of polling
• re-register while command failed with return code
  510
• Access list

11
Authentication

• Scheme Negotiation
• Currently defined scheme
• Listed clients
• Password
• Public Key
• SSLv3

12
Requests 1/2

• Manager Side
• ManagerMigration
• RefreshAccessList
• StatusReportPolling
• StatusReportPush
• DisplayMessageAlert
• AgentReset
• HardwareReset

13
Requests (2/2)

• Manager Side
• UpdateFirmware
• LaunchApplication
• ForceLogout
• Agent Side
• GetAccessList
• OnlineHelp

14
Status Report

• MIME format
• Polling or Push mode
• Report Items
• ActivePage
• StorageUtil
• MemoryUtil
• NetworkUtil
• TotalUtil
• UserStatics

15
Sample Conversation

• A AGENT 0 REG pc1 ntucsie
• M 200 Accepted. ManagerIdC7200AE7
  AgentIdS4432768
• M MANAGER C7200AE7 AUTH SSLv3
• A 500 not supported currently.
• M MANAGER C7200AE7 RQST StatusReportPush 300000
• A 200 Sending status report every 5 minutes.
• M MANAGER C7200AE7 RQST RefreshAccessList
  FOLLOWING
• deny all
• .
• A 200 Access list accepted.
• .... 17 minutes later
• A AGENT S4432768 LOGIN kevin
• M 200 User kevin added to online list.

16
Sample Conversation

• M MANAGER C7200AE7 RQST RefreshAccessList
  FOLLOWING
• allow all
• deny www.geocities.com
• .
• A 200 Access list updated.
• ..... five minutes later
• A AGENT S4432768 REPO FOLLOWING
• ActivePage http//www.hinet.net/index.html
• MemoryUtil 75
• UserOnline kevin
• .
• M 200 Report received. Good boy. )
• .... 3 hours later
• A UNREG C7200AE7
• M 200 Agent pc1/ntucsie quit.

17
Implementation Issues for Agents

• iCava Webpads
• Linux kernel proprietary window system
• Full TCP/IP implementation
• Complete SDK Windows Emulator
• Threads
• 2 threads for listening sending reports
• commands responses parsing

18
Implementation Issues for Agents

• Access List
• Client side receive the access list from server
• Browser on WebPad deny or allow some pages viewed
  by user
• SSLv3

19
Implementation Issues for Managers (1/2)

• Manager is written by BCB.
• Why Java ?
• Java can run on everywhere.
• Javas java.net. package is simple and ease to
  use.
• BUT, Im not familiar with Java AWT. So GUI
  design is difficult.

20
Implementation Issues for Managers (2/2)

• Why BCB ?
• BCBs RAD environment is convenient
• BCBs VCL component is also easy to program.
• Deed not to care about the thread detail (the
  event driven do this for you)
• Possible improvement
• Port the Manager to Java, so it can run on
  anywhere, even server side is also a mobile
  device or embedded system

21
Conclusion Future Works

• Meets our requirement
• Incomplete Implementation
• Authentication
• Security issue
• Load balancing
• Grouping
• Group management policy