Janos
A Java-based Active Network
Operating System
Jay Lepreau, Patrick Tullmann, Kristin Wright
Wilson Hsieh, Godmar Back, many more...
University of Utah
Flux Research Group www.cs.utah.edu/flux/
March 30, 1999
Department of Computer Science Janos Project

Goals

Develop a principled yet efficient local OS architecture for active nodes, oriented to hierarchical structure, resource control , and security.

Produce separately useful OS, security, and Java VM components.
Department of Computer Science Janos Project

Goals 2

Investigate local resource management and security in language-based systems
– Java, in particular

Investigate OS support for active networking

Investigate broader resource management issues
Department of Computer Science Janos Project

Resources (obvious)

Memory

CPU

Network bandwidth
Department of Computer Science Janos Project

Resources (less obvious)

Backing/caching store

Persistent store


Encryption hardware
Other specialized hardware…
– DSPsl
– Reconfigurable HW?
– Special links (eg long set up time)

Specialized data...
– Routing table entries?
– ...
Department of Computer Science Janos Project

Genesis

Builds on three lines of existing work:
– Fluke Nested Process Model
»
Strong OS model with a new protection mechanism: focus on resource control
– Flask security architecture
» Policy-flexible fine-grain mechanisms
– The OSKit
»
Reusable low-level components and a framework (COM, APIs)

Other:
– Optimization of Java for systems code
» predictability, speed
– Network testbed (possibly)
Department of Computer Science Janos Project

Department of Computer Science
Janos Structure
AN Execution Environment
Janos VM
The OSKit
Hardware or Unix
Janos Project

Primary Execution Environment

Java-based

Prototype will be based on ANTS [Wetherall et al. 97]
– Initial changes to ANTS structure and execution model to better support resource control (released June ‘98)

Integration with Janos resource management
– Admission control
– Prevent denial of service
– Fair sharing
Department of Computer Science Janos Project

The Nested Process Model
Child process is encapsulated in its parent.
Traditional Process Model
Parent
Process
State
Nested Process Model
Child
State
Parent
Process
State
Child
State
Child
State
Child
State
Parent has complete control over the child
.
Department of Computer Science

Nested Process Model
Parent
Process
State
Child
State
Parent
Process
State
Child
State
Child
State
Child
State




Traditional Fluke
Derived from a recursive virtual machine model
Resources for a process are obtained from parent
Parent services requests for new resources and for management
Strict hierarchy enabled, not enforced
Department of Computer Science Janos Project


Fluke: microkernel and server implementation of OS model

Flask: high-security version of Fluke

Alta: Fluke architecture implemented in a JVM, using type-safety for memory protection
Department of Computer Science Janos Project

Department of Computer Science
Swap in Patrick
Janos Project


Joint with NSA R23, SCC

Security architecture orthogonal to Flask implementation

Augments Fluke with fine grained security mechanisms
– Explicit security bindings
– Mandatory controls
– Mutual authentication
Department of Computer Science Janos Project

Flask: Security Policy

Policy flexibility:
– Dynamic both in time and in configuration
– Economic and market reasons
– Separate security policy “decider” makes all policy decisions
– Revocation support

Investigating extensions to multiple policy servers
Department of Computer Science Janos Project

The OSKit
Department of Computer Science Janos Project

Dual Execution Modes
Department of Computer Science Janos Project

User
Friendly
OS
Development
….!?
Department of Computer Science Janos Project

Example Working Kernel
#include <stdio.h> main()
{ printf("Hello, world.\n"); return 0;
}
Department of Computer Science

OSKit Status

Major releases 18 Dec 98, 15 Jan 99
– Unique downloads running 1000/month
– 600 on mailing list

Base for Janos prototype on bare hardware

Another route for Utah/NSA security tech xfer

Likely vehicle for external OS research tech xfer
(Quorum, NT)

Evolving into flexible OS itself
Department of Computer Science Janos Project

OSKit: Ongoing and Future

Make components more separable

Dynamic loading and linking


Module configuration language & GUI
“Protection” component


Further integrate with languages
– Java
– Scheme (Indiana, Kansas, Rice)
– ML (MIT, CMU)
….
Department of Computer Science Janos Project

OSKit future components

Buffering/caching (IO-Lite?), network mgmt protocols, ...

Modular protocol impl.

Secure boot (Penn), filesys (Linux xfer), policy engine

Network components
– access checks at all levels and objects (local node, remote node, interface, routing table, …)

Crypto, auth,


PCC verifier (w/ CMU/Cedilla)
….
Department of Computer Science Janos Project

CPU Inheritance Scheduling

Threads schedule each other by donating the CPU using a directed yield primitive

One root scheduler per processor sources all CPU time

Kernel d ispatcher manages threads, events, and CPU donation without making any scheduling policy decisions
Department of Computer Science Janos Project

Stride (WFQ) Scheduling
50
20 % CPU
400
600
50
20 % CPU
60 % CPU
Department of Computer Science Janos Project

Possible Curves in the Road

Fluke model will likely be modified

Hardware protection may be included

Flask security architecture may not map well to Java and Janos


Challenges in GC and cpu interactions.
More surprises undoubtedly await…
Department of Computer Science Janos Project

The Big Todo

GVM and Alta prototypes: evaluate, choose best pieces, synthesize

Evaluate use of hardware protection in the OSKit

Refine and integrate AN execution environment

Measure and tune performance

Leverage AN-specifc fine-grained sharing
Department of Computer Science Janos Project

Summary

Resource control and security in Java
– Applicable in other language-based systems
– Explore power/speed of software mechanisms

Primary motivation: active networks and other mobile code

Useful in other contexts
– Servlet environments
– Active service environments
– OS without hardware protection

Wide applicability and tech xfer thru the OSKit
 www.cs.utah.edu/flux/
Department of Computer Science Janos Project