A presentation by Dr. Robin Upton (2008-11-02).

Available for download at www.altruists.org/ff1

Attribution – NonCommercial - ShareAlikewww.altruists.org

FF1: Friend2Friend Technical Overview

What is a Friend2Friend Network?

v1.0.1

What is a Friend2Friend (F2F) Network?

. Friend2Friend.net?

In Client-Server networks (Websites), unprivileged clients connect to more powerful servers.

C C C C C C C

S

In Peer2Peer networks (Napster, BitTorrent ...) users connect, sometimes via a central server, to random individuals (peers).

P

S P

PP

PP

P

P

In Friend2Friend networks, you connect yourself directly to known individuals (friends).

F

F F

F FF

Friend2Friend.net

. F2F Network

Home of an F2F system that ...

is XML-based;

has a GUI/SDK for FireFox;

is Free & Open Source;

is not yet working ;-)

is Extensible/scriptable in XSLT;

F2F Network

F2F Structure

f2f.RobinUpton.com

f2f.ekushey.org

f2f.honesty.org f2f.gifteconomy.org

f2f.re-cycle.org

Connections

Server-Server

Client-Server

f2f.emni.com.bd

Like WWW servers, F2F servers both send and receive data.

Unlike WWW, traffic is digitally signed, & packets travel between F2F servers in multiple hops.

F2F Structure

Client Structure

The F2F network is built from 2 sorts of node

'Client' Node

'Server' Node

Interaction with users

JS + Java Intermittent (on demand)

Data storage and communication

PHP + Java24/7

PurposeCodingAvailability

Client Structure

Server Structure

Human-readable

DOM

Machine- readable

DOM

Display

XMLJAVA

Decryption

Handle Events, clipboard etc.

The F2F client runs in a browser, managing traffic, making the HTML to show the user & responding to user interaction.

OutJAVA

Encryption

p9;45p[54t[po'kljh67O:M SEESuDETB6ED7iEuho DEDE ^Teu#'[hEB B GE& E7Unun KDUCe IunKDE{OccsdcscdK OKDEJ JLKJE LKDEED'@sdf 45r;oki4IOiJKkujYT-0345

p9;45p[54t[po'kljh:M0 SEESuDETB6ED7iEuhoEDE ^Teu#'[hEB B GE& E7Un emni09wd;lkjIU£'jk3e

In

<window:window> <section location=”top”> <icon:icon/> <f2f:tagline/> <f2f:login-box/> </section> <section location=”left”> <link id=”3”/> ... <link id=”5”/> </section> </window:window>

Server Structure

Soft Nodes

The F2F server is a tree of

nodes, called soft nodes.

/f2f

/f2f/users

/f2f/users/jim

/f2f/lib

/f2f/lib/demo

/f2f/users/tom

/f2f/lib/etc

/f2f/users/jim .../public

<f2f:message> 'bubble' around

the tree...

JAVA Decryption

p9;45p[54t[po'kljh67O:M SEESuDETB6ED7iEuho DEDE ^Teu#'[hEB B GE& E7Unu IunKDE{OccsdcscOKDELKJE LKDEED'@sdfKkujYT-0345;Incoming Outgoing

p9;45p[54t[po'kljh:M0 SEESuDETB6ED7iEuhoEDE ^Teu#'[hEB B GE& E7Un emni09wd;lkjIU£'jk3eJAVA

Encryption

...transformed by sets of XSD/XSLT

filters between nodes as they

do so.

Soft Nodes

Modules

Each soft node has...

(1) a namespace, identifying its type

http://friend2friend.net/modules/user

(3) a store of user data

(2) a unique path on that server

/f2f/users/jim

(4) the system's record of ongoing transactions

Soft nodes are installed from F2F modules. They are analagous to installed software.

/f2f/users/jim

default.xml

dynamic.xml

Modules

Message Structure

An F2F module has...

F2F Modules add extra functionality; they are analagous to software installers.

(5) An XSLT script for each service, display or filter

(3) A list of any services & displays it provides

(4) A list of filters it uses

(2) A schema to define its datatypes

(1) A unique namespace and matching digital signaturehttp://friend2friend.net/modules/user

Message Structure

Bubbling Messages

<f2f:message type=“down”>

<f2f:message>

<f2f:to node= “/f2f/users/tom”>

<f2f:from node= “/f2f/users/jim” thread= ”2” sreq=”6” >

<f2f:data>

... Any XML, (typically <f2f:servicereq... >)

</f2f:data>

/f2f/users

/f2f/users/jim

/f2f/users/tom

Thread #2

XX MM

LL

Between F2F servers, <f2f:messages> are encrypted and signed.

Bubbling Messages

Receiving Messages

On receipt of data from the outside...

1) The F2F server uses its private key to produce a decrypted <f2f:message>

2) If this does not have a valid <f2f:to> address, discard it.

Else bubble the <f2f:message> from root

To bubble <f2f:message> from a softnode:

1) If it is at the node specified in <f2f:to>, receive the <f2f:message> here. Else:

2) Execute any filters which apply to the message.

3) If <f2f:to> is an external address, and here is root, send out the message

Else move the resulting message one node towards <f2f:to> and bubble

Receiving Messages

Crunching Threads

1) Create a new <f2f:thread>, setting

<f2f:from> = the <f2f:from> item of the <f2f:message><f2f:data> = the <f2f:data> item of the <f2f:message>

2) Crunch this thread.

To receive <f2f:message> at a soft node:

Crunching Threads

Finishing Threads

1) If <f2f:data> contains no active <f2f:servicereq> items, finish <f2f:thread> here.

Else execute the next active <f2f:servicereq> in <f2f:thread> here,

then crunch <f2f:thread> here...

To crunch <f2f:thread> at a soft node:

Finishing Threads

To finish <f2f:thread> at a soft node:

1) Create a new <f2f:message>, setting

@type = “term”<f2f:to> = the

<f2f:from> of this <f2f:thread><f2f:from> = this node's address

<f2f:data> = the <f2f:data> of this <f2f:thread>

2) Remove this <f2f:thread>

3) Bubble this <f2f:message>

Executing <f2f:servicereq>

Executing <f2f:servicereq>

Rerouting <f2f:servicereq>

To execute <f2f:servicereq> in <f2f:thread> at a soft node:

1) Look up @function in this node's table of addresses

2) If it is not present, fail.

Elseif this address is elsewhere, reroute <f2f:servicereq> to that address

Else process <f2f:servicereq> in <f2f:thread> here

Rerouting <f2f:servicereq>

Processing <f2f:servicereq>

To reroute <f2f:servicereq> at a soft node to another soft node:

1) Create a new <f2f:message> item, setting

@type = “down” <f2f:to> = the other node's address<f2f:from> = this node's address<f2f:data> = the <f2f:servicereq>

2) Bubble this <f2f:message>

Processing <f2f:servicereq>

To process <f2f:servicereq> in <f2f:thread> at a soft node:

1) Carry out any pre-processing directives on <f2f:servicereq>

2) If @function is a core service, pass <f2f:servicereq> to the appropriate PHP() call

Else apply the appropriate .XSLT to <f2f:servicereq>

3) Carry out any post-processing directives on the data returned by 2)

4) Remove <f2f:servicereq> from <f2f:thread> and replace it by the output of 3)

. All you need to know to start coding...

All you need to know to start coding...

Key Aspects

<random-xml-parent included="for clarity's sake"><f2f:servicereq name=”http://example.org/f2f”>

... optional XML children here ...</f2f:servicereq>

</random-xml-parent>

<random-xml-parent included="for clarity's sake"><example:result xmlns:example=”http://example.org/f2f”>

... some block of XML data here, maybe ...</example:result>

</random-xml-parent>

Key Aspects

XML for all data exchange.

Strong Cryptography secures all internet traffic.

Non-hierarchical system architecture.

XSLT-based scripting language.

FF F

F FF

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