Open Source: An Introduction to the AllJoyn Project

Greg BurnsSenior Director, Engineering, Qualcomm Innovation Center, Inc.

Agenda

AllJoyn Overview Architecture and Concepts Security Framework Performance Considerations Code Example Q&A

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AllJoyn Overview

What is AllJoyn?

AllJoyn is a new proximity based mobile peer-to-peer software framework developed by Qualcomm Innovation

Center, Inc. ("QuIC")

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What we mean by Peer-to-Peer

But, How Do You Find and painlessly connect

to devices around you Discover services running on devices Adapt to devices coming and going Deal with different transports Interoperate across different

operating systems Exchange information and services Provide reliable performance

in wireless environments Ensure no one nearby maliciously

hacks into your phone

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Simple Definition:Communicating withstuff around you without need for a server

Framework: Removing Barriers

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Performance Optimizations

Transport/ OS Agnostic

LanguageBindings

Managed Networking

SimpleDiscovery

Developers write to a simple API

* Supportforthcoming

SessionsLower Latency

Point to MultipointRaw-Data

RoutingMulti-Threading

Data MarshallingAd-hoc networks

ServiceDevice

JavaC++

JavaScript

BT / Wi-FiAndroid/Linux/

Windows* Wi-Fi Direct

Fueling Innovation and Enabling New User Experiences

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SOCIAL APPLICATIONS

INFORMATION EXCHANGE

MULTIPLAYER GAMING

P2P AUGMENTED REALITY

GROUPWARE PROXIMITY-BASED SERVICES

MEDIA ENTERTAINMENT

Why Develop AllJoyn?

Simplify and extend device inter-communication capabilities

Always-on always-connecting

Fuel new and creative application usage models

OS independent platform for peer-to-peer innovation

Seed the peer-to-peer application ecosystem

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An Open Source Project

AllJoyn Open Source Project: www.alljoyn.org

Launched Jan. 2011 GitHub hosts source Apache 2.0 License

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Documentation SDK Tools Contribute Download Forums

Architecture Concepts

Architecture Overview

AllJoyn is a distributed software bus Each device runs a bus daemon Applications communicate directly only with the daemon Daemons on each device communicate with daemons on other

devices Daemons do message routing and namespace management

Bus formation is ad hoc Based on proximal discovery Abstracts multiple discovery mechanisms

Protocol is transport independent Ground-up implementation of the DBus wire-protocol with extensions Supports Wi-Fi and Bluetooth currently

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Why the Dbus Wire Protocol?

Why reinvent the wheel? www.freedesktop.org/wiki/Software/dbus

IPC mechanisms used on many Linux distributions Deeply integrated with system services and session management Supports RPCs as well as unicast and multicast events

Object oriented Objects, interfaces, methods, and properties

Language neutral Bindings for C, Java, Python, Perl, etc.

Message bus architecture RPC and events implemented as messages Daemon handles messaging routing between clients

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DBus Compatibility

Distributed Bus

Management

Distributed Bus

Management

Peer sessionsPeer sessionsService

Advertisement & Discovery

Service Advertisement

& Discovery

Device-to-device message routing

Device-to-device message routing

Authentication&

Encryption

Authentication&

Encryption

Header Compression

Header Compression

Message Expiration (TTL)

Message Expiration (TTL)

Raw Sessionsupport

Raw Sessionsupport

BluetoothBluetooth

Topology management

Topology management

Wire-protocolWire-protocol

Object modelObject model

Routing rulesRouting rules

Client-bus authentication

Client-bus authentication SignalsSignals

Name spaceName space

IntrospectionIntrospection Remote procedure callRemote

procedure call

WiFiWiFi

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DBus Compatibility

Message Types and Properties

Serial numberfor matching method replies to method calls Senderautomatically inserted by AllJoyn Destinationnull for broadcast or multicast messages Object-pathpath to an object Interfaceinterface name implemented by named object Membermethod name or signal name Signaturespecifies argument types for data payload Session IDfor device-to-device communication Payloaddescribed by the signature

1. Signalsasynchronous event broadcast, multicast, or point-to-point2. Method Callscall portion of an RPC3. Method Repliesreturn portion of an RPC4. Errorserror response to an RPC

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Bus Attachments, Objects, Proxy Objects An application needs a Bus Attachment to communicate with the bus

Bus Attachments provide a root (/) for the object hierarchy

Bus Objects implement interfaces Bus Objects path names look like file paths, e.g. /org/AllJoyn/Games/chess Bus Object have methods than can be called remotely Bus Objects can emit signals

Proxy Bus Objects are local representations of remote Bus Objects Applications use proxy bus objects to make method calls to remote objects

BusBus

Bus Attachment Bus Attachment

BusObject Tree

Application Application

ProxyObject

Event handler

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Distributed Software Bus

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App X

Device 1

App Y

Daemon

App X

Device 2

Daemon

App Y

Device 3

App Z

Daemon

Conceptually peers are applications, not devices.

Applications communicatewith a local daemon.

Daemons handle routing between devices.

TCP or BluetoothLocal socket

Ad-hoc Bus Formation

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Device

Daemon

Actual discovery mechanism is transport dependent: On Wi-Fi a lightweight IP multicast protocol. On Bluetooth device discovery with EIR and SDP query. On Wi-Fi-Direct TBD.

Find-Name request

Eureka!

Device

Daemon

Find-Name request

Client App Service App

Ad-hoc Bus Formation

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Device

Once connected, daemons form single bus with shared namespace- Peers can discover when other peers join or leave bus- Peers can make RPC calls and send and receive events

Device

Peer Session

Distributed Bus

Client App Service App

Daemon Daemon

- Session reference counting keeps device-to-device connections alive- Multicast events can be sent to all peers in the session

Security Framework

Security Framework

Authentication and encryption is app-to-app: The bus is not involved other than to route.

Trust relationship established between the applications. Device pairing not required unless the transport requires it. In case of Bluetooth, AllJoyn does not normally trigger pairing.

Security is enabled per-interface: Authentication and key exchange initiated on demand.

Security-enabled interface: Authentication is required to make method calls. Authentication required to receive signals.

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AllJoynDistributed Bus

AllJoynDistributed Bus

AllJoynApplication

AllJoynApplication

AllJoynApplication

Security ModelAuthentication and Encryption

Signals from a security-enabled interface are encrypted and authenticated

Application can allow a mix of security-enabled and non-secure interfaces. Maintain own key storecan use password

Method calls to security-enabled interface are encrypted and authenticated. If call encrypted, so is reply

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Key Store

Key Store

Key Store

Built-in Authentication Mechanisms

Three mechanisms supported Mechanism negotiated using SASL protocol Application developer chooses which mechanism to use Algorithms adapted from TLS protocols per RFC 5246

Pin-code Authentication with a single-use password Trust relationship is persistent

Logon User name and password type Password required every time peers connect

Certificate-based RSA public key authentication and X.509 certificates Trust relationship lasts while certificate valid

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Encrypted Message

Serial #

Header length

Body length

Header fields

Zero padding

Body

Authenticationfield

Endian flagVersion #Flag bits

Message type

Indicates message is encrypted

The header and the body are authenticated using AES-CCM .

The body (payload) is encrypted. The header is required for routing, so

is authenticated but not encrypted. Structurally an encrypted message

still conforms to the DBusspecification.

Authenticatedheader

0-7 bytes

Body lengthbytes

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Performance Considerations

Message Efficiency

Time to live: Added for multi-player games and streaming where stale data is useless. Mainly applies to signals. Introduces a new message header field. Expired messages are silently discarded.

Header compression: Significantly reduces the size of message headers. Intended for messages that are sent frequently. Allows short messages to fit into single-slot Bluetooth packets.

Multipoint sessions: Bounds the scope of broadcast signals to session members. Provides mechanism for deciding when radios are no longer in use.

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Direct Point-To-Point Bulk Data Exchange

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Removes overhead by providing direct access to underlying socket

Application can read/write any data to the socket

Removes overhead by providing direct access to underlying socket

Application can read/write any data to the socket

Raw Sessions

1. AllJoyn sets up a peer-to-peer normal session

2. Peers call daemon to obtain the file descriptor for socket

3. Daemon returns open file descriptors to peers, closes session

4. Session is gone but sockets remain open

1. AllJoyn sets up a peer-to-peer normal session

2. Peers call daemon to obtain the file descriptor for socket

3. Daemon returns open file descriptors to peers, closes session

4. Session is gone but sockets remain open

Process

Code Snippets

Language Bindings

Native implementation for AllJoyn is C++ Java binding is available for Android Binding for JavaScript is under development Considering bindings for C, Python, and Lua Object model is similar for all bindings

Create a BusAttachment to connect to the bus Create BusInterfact(s) that will be implemented by BusObjects Create and register BusObject(s) with the BusAttachment BusObjects handle remote method calls and emit Signals Applications call methods on remote objects using

ProxyBusObjects Applications register Signal handlers with BusAttachment

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AllJoyn Hello World in Java*import org.alljoyn.bus.BusException;import org.alljoyn.bus.annotation.BusInterface;import org.alljoyn.bus.annotation.BusMethod;

/** This interface implements a simple echo method that returns the same string* that is receives.*/

@BusInterfacepublic interface EchoInterface {

/** Echo a string.** inStr is the string to be echoed by the service, returns the echoed string.*/

@BusMethod(signature="s, replySignature="s")public String Echo(String inStr) throws BusException;

}

* Code snippets licensed under the Apache License, version 2.0 http://www.apache.org/licenses/LICENSE-2.0

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The Echo Service*public class Service implements EchoInterface, BusObject {

public static void main(String[] args) {/* Create a bus connection and connect to the bus */BusAttachment bus = new BusAttachment(Service.class.getName());bus.connect();/* Register the service */Service service = new Service();bus.registerBusObject(service, "/myobject");/* Request a well-known name */try {

bus.RequestName("org.alljoyn.echo", REQUEST_NAME_NO_FLAGS);} catch (BusException ex) {return;}/* Echo until told to stop */while (!stop) { Thread.currentThread().sleep(10000); }

}/* Implementation of the echo method */public String Echo(String inStr) {

return inStr;} }

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* Code snippets licensed under the Apache License, version 2.0 http://www.apache.org/licenses/LICENSE-2.0

The Echo Client*public class Client {

public static void main(String[] args) {

/* Create a bus connection and connect to the bus */BusAttachment bus = new BusAttachment(Client.class.getName());bus.connect();/* Get a remote object */Class[] ifaces = { EchoInterface.class };ProxyBusObject proxyObj = bus.getProxyBusObject("org.alljoyn.echo", "/myobject", ifaces);EchoInterface proxy = proxyObj.getInterface(EchoInterface.class);

/* Call the ping method on the remote object */try {

String ret = proxy.Echo("Hello World");System.out.println(Echo returned: " + ret);

} catch (BusException ex) {return;

}}

}

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* Code snippets licensed under the Apache License, version 2.0 http://www.apache.org/licenses/LICENSE-2.0

Summary

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OS and platform independent

Multiple language bindings

Multiple transports

OS and platform independent

Multiple language bindings

Multiple transports

Easier P2P Development

Launched January 2011

SDK download and forums at www.alljoyn.org

Sourced code available on GitHub at www.github.com/alljoyn

Launched January 2011

SDK download and forums at www.alljoyn.org

Sourced code available on GitHub at www.github.com/alljoyn

Open Source Sponsored by QulC

Download SDK Download Source Code Contribute

Questions?

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Nothing in these materials is an offer to sell any of the components or devices referenced herein. Certain components for use inthe U.S. are available only through licensed suppliers. Some components are not available for use in the U.S.

Disclaimer

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QUALCOMM Innovation Center, Incorporated5775 Morehouse Drive

San Diego, CA. 92121-1714U.S.A.

Copyright 2011 Qualcomm Innovation Center, Incorporated.

All rights reserved.

Not to be used, copied, reproduced in whole or in part, nor its contents revealed in any manner to others without the expresswritten permission of Qualcomm.

Qualcomm and Uplinq are trademarks of Qualcomm Incorporated, registered in the United States.

ALLJOYN is a trademark of Qualcomm Innovation Center, Inc.

Other product and brand names may be trademarks or registered trademarks of their respective owners.