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authorAlex Auvolat <alex.auvolat@ens.fr>2014-12-01 21:10:35 +0100
committerAlex Auvolat <alex.auvolat@ens.fr>2014-12-01 21:10:35 +0100
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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:x="http://www.texmacs.org/2002/extensions" xmlns:m="http://www.w3.org/1998/Math/MathML">
+ <head>
+ <title>No title</title>
+ <meta content="TeXmacs 1.99.2" name="generator"></meta>
+ <style type="text/css">
+ body { text-align: justify } h5 { display: inline; padding-right: 1em }
+ h6 { display: inline; padding-right: 1em } table { border-collapse:
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+ margin-left: -0.4em; top: -0.1em } .title-block { width: 100%;
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+ inline-block; padding: 0.2em; } .right-tab { float: right; position:
+ relative; top: -1em }
+ </style>
+ </head>
+ <body>
+ <table class="title-block">
+ <tr>
+ <td><table class="title-block">
+ <tr>
+ <td><font size="+3"><b>The NARP protocol specification
+ </b></font></td>
+ </tr>
+ </table><table class="title-block">
+ <tr>
+ <td><font size="+1"><b>A Generic Recursive Communication Protocol for
+ Networked Applications</b></font></td>
+ </tr>
+ </table></td>
+ </tr>
+ </table>
+ <p>
+ In this document we explain the purpose and provide a draft
+ specification for the NARP protocol, a general-purpose networking
+ protocol destined to be used in many layers of a new operating system
+ and networking system.
+ </p>
+ <h2 id="auto-1">1<span style="margin-left: 1em"></span>Introduction</h2>
+ <p>
+ We begin by remarking that a basic operation in all computer operation
+ processes consists in naming objects and providing acces to these named
+ objects. Here are a few examples of naming in real use cases:
+ </p>
+ <ul>
+ <li>
+ <p>
+ Naming of files on a local or distant file system
+ </p>
+ </li>
+ <li>
+ <p>
+ Naming of devices in the <tt class="verbatim">/dev</tt> virtual filesystem on
+ Unix machines
+ </p>
+ </li>
+ <li>
+ <p>
+ Naming of networked machines (with IP adresses and DNS records)
+ </p>
+ </li>
+ <li>
+ <p>
+ Naming of internet ressources over protocols such as HTTP, IMAP,
+ IRC, specfic web services, &hellip;
+ </p>
+ </li>
+ </ul>
+ <p>
+ We propose here a novel architecture with the purpose of unifying all
+ the naming happening at all levels of the system, with two base concepts
+ : <em>objects</em> and <em>service</em>.
+ </p>
+ <ul>
+ <li>
+ <p>
+ <em>objects</em> are ressources that may implement different
+ semantics : bidirectionnal communication (such as sockets) ;
+ unidirectionnal communication (FIFO-like) ; file semantics ; etc.
+ </p>
+ </li>
+ <li>
+ <p>
+ <em>services</em> are a way of naming objects, querying the
+ interfaces they implement, and multiplexing communications with them
+ </p>
+ </li>
+ </ul>
+ <p>
+ We suggest that a NARP service may be provided on any bidirectionnal
+ channel of communication supporting the (reliable) sending and recieving
+ of messages. In addition, NARP objects may implement such a send/recieve
+ interface ; therefore a NARP service can be channeled into an object.
+ Such a construction of using a NARP object to access a NARP service is a
+ fundamental operation that we call <em>recursive multiplexing</em>, or
+ just <em>multiplexing</em>.
+ </p>
+ <p>
+ The NARP protocol is a client/server protocol meant to include a variety
+ of different operations that may or may not be implemented by a specific
+ NARP server.
+ </p>
+ <h2 id="auto-2">2<span style="margin-left: 1em"></span>High-level overview</h2>
+ <h3 id="auto-3">2.1<span style="margin-left: 1em"></span>The basic operations on services and
+ objects</h3>
+ <p>
+ A NARP service is basically any object that implements the following
+ operations:
+ </p>
+ <ul>
+ <li>
+ <p>
+ <em>query</em> : get information on a ressource identified by name
+ </p>
+ </li>
+ <li>
+ <p>
+ <em>list</em> : know the names of ressources presented by the
+ service (possibly in a specific sub-path)
+ </p>
+ </li>
+ <li>
+ <p>
+ <em>attach</em> : get an object interface for accessing a ressource,
+ identified by name
+ </p>
+ </li>
+ </ul>
+ <p>
+ A NARP object is basically any object that implements the following
+ operations :
+ </p>
+ <ul>
+ <li>
+ <p>
+ <em>send</em> : send a message (an arbitrary byte string) to the
+ object
+ </p>
+ </li>
+ <li>
+ <p>
+ <em>recieve</em> : recieve a message from the object (this may be
+ done asynchronously with handler functions)
+ </p>
+ </li>
+ <li>
+ <p>
+ <em>detach</em> : delete object connection
+ </p>
+ </li>
+ </ul>
+ <h3 id="auto-4">2.2<span style="margin-left: 1em"></span>The basics of the NARP protocol</h3>
+ <p>
+ Given any interface with send/recieve capabilities considered as an
+ assymetric (client/server) configuration, the following client messages
+ consitute the basics of the NARP protocol for providing a NARP service
+ on the interface:
+ </p>
+ <ul>
+ <li>
+ <p>
+ <tt class="verbatim">hello</tt> : initialize a connection, check version
+ information, &hellip;
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">authenticate</tt> and appropriate response messages : use
+ credentials (user/password or access token) to gain acces to some
+ ressources provided by the server (the protocol is thus statefull)
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">walk</tt>, <tt class="verbatim">list</tt> and appropriate response
+ messages : get information about the available ressources
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">attach</tt> and appropriate response messages : give an
+ identifier (a descriptor) to a ressource in order to communicate
+ with it
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">send</tt> and appropriate response messages : send a
+ message to an attached ressource, identified by its descriptor
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">detach</tt> : close a descriptor and detach from a
+ ressource
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">create</tt>, <tt class="verbatim">delete</tt>, <tt class="verbatim">rename</tt>,
+ <tt class="verbatim">link</tt> : requests the creation or modification of a
+ ressource in the namespace
+ </p>
+ </li>
+ </ul>
+ <p>
+ The server may also at any moment send a message, including:
+ </p>
+ <ul>
+ <li>
+ <p>
+ a response to a query
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">recieve</tt> : a notification of a message sent from the
+ object to the client
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">detached</tt> : the connection to the object has been
+ terminated by the object server
+ </p>
+ </li>
+ </ul>
+ <h3 id="auto-5">2.3<span style="margin-left: 1em"></span>Recursion</h3>
+ <p>
+ If an object is a NARP server, the messages sent to it and recieved from
+ it are messages of the NARP protocol. Otherwise, they are arbitrary.
+ </p>
+ <h3 id="auto-6"><a id="rev-sock"></a>2.4<span style="margin-left: 1em"></span>Reverse object</h3>
+ <p>
+ Some NARP servers may support reverse object serving: the client creates
+ an object on the server and handles all the requests arriving to this
+ object (therefore the initial NARP server only serves as a relay between
+ the new server and its clients
+ <p>
+ <font size="-1"><div align="justify">
+ <div style="margin-left: 0px">
+ <div style="margin-right: 0px">
+ <class style="font-style: normal"><p>
+ 1. Research is to be done on shortcutting mechanisms in
+ specific situations where too many levels of recursion cause a
+ performance issue.
+ </p></class>
+ </div>
+ </div>
+ </div></font>
+ </p>
+ <span style="margin-left: 0em"></span>
+ <a id="footnr-1"></a>
+ <sup><class style="font-style: normal"><a href="#footnote-1">1</a></class></sup>
+ ). A client wishing to act as a reverse object server may use the
+ following commands:
+ </p>
+ <ul>
+ <li>
+ <p>
+ <tt class="verbatim">serve</tt> : listen for attach requests on a servable
+ (empty) object created in the server namespace (if authorized)
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">accept</tt> and <tt class="verbatim">reject</tt> : accept (or
+ reject) an attach request to the object
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">detach</tt> : close connection between object and client
+ (this is the same detach message as in standard communications)
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">unserve</tt> : stop serving for the object. Attached
+ clients continue to be attached.
+ </p>
+ </li>
+ </ul>
+ <p>
+ The server may in turn send the following messages concerning the server
+ object:
+ </p>
+ <ul>
+ <li>
+ <p>
+ <tt class="verbatim">attach_request</tt> : a client is willing to attach to
+ the object. A descriptor is already associated to the connection to
+ be established, but the server may reject it.
+ </p>
+ </li>
+ </ul>
+ <p>
+ Once a client is attached to the object, a classical send/recieved
+ interface is provided.
+ </p>
+ <p>
+ Typically, the protocol exchanged over the object is NARP protocol,
+ therefore enabling the reverse server to provide its own namespace and
+ other functionnality.
+ </p>
+ <h3 id="auto-7">2.5<span style="margin-left: 1em"></span>Specific object types and associated
+ messages</h3>
+ <h4 id="auto-8">2.5.1<span style="margin-left: 1em"></span>Objects are sockets</h4>
+ <p>
+ Sockets are the basis of the NARP protocol : attaching to an objects
+ opens a socket connection to the process serving the object, and when
+ the connection is accepted, basic send/recieve functionnality is
+ provided. See also the reverse object protocol described in section <a
+ href="#rev-sock">2.4</a>.
+ </p>
+ <h4 id="auto-9">2.5.2<span style="margin-left: 1em"></span>File objects</h4>
+ <p>
+ Small files may implement the following interface:
+ </p>
+ <ul>
+ <li>
+ <p>
+ <tt class="verbatim">put</tt> : erase the whole file and put the transmitted
+ content
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">get</tt> : retrieve the whole file content
+ </p>
+ </li>
+ </ul>
+ <p>
+ Big files may implement the following interface:
+ </p>
+ <ul>
+ <li>
+ <p>
+ <tt class="verbatim">write</tt> : write a portion of the file at a given
+ offset
+ </p>
+ </li>
+ <li>
+ <p>
+ <tt class="verbatim">read</tt> : read a portion of the file at a given offset
+ </p>
+ </li>
+ </ul>
+ <h4 id="auto-10">2.5.3<span style="margin-left: 1em"></span>User IO (terminals&hellip;)</h4>
+ <p>
+ Virtual terminals can be seen as objects implementing a simple
+ send/recieve semantic, where the data transmitted is unstructured (or
+ structured given a specific terminal data structure). More specific
+ interfaces can be defined for advanced terminals and GUIs.
+ </p>
+ <h4 id="auto-11">2.5.4<span style="margin-left: 1em"></span>Specific applications</h4>
+ <p>
+ Specific applications may define custom messages. Examples include:
+ </p>
+ <ul>
+ <li>
+ <p>
+ e-mail
+ </p>
+ </li>
+ <li>
+ <p>
+ instant messaging
+ </p>
+ </li>
+ <li>
+ <p>
+ collaborative editing of text-based documents
+ </p>
+ </li>
+ </ul>
+ <p>
+ and many other applications yet to be invented.
+ </p>
+ <h3 id="auto-12">2.6<span style="margin-left: 1em"></span>Big messages</h3>
+ <p>
+ The message size in the NARP protocol is limited to 64kb, and
+ recommended not to exceed 4kb+header (4kb is the size of a memory page
+ on many machines). Therefore a possibility would be for the NARP
+ protocol to include a way to transmit big messages by fragmenting them
+ into small messages. Optionnal error correction may be included. This
+ can be useful for example when using <tt class="verbatim">put</tt> or <tt class="verbatim">get</tt>
+ on large files, or <tt class="verbatim">read</tt>s and <tt class="verbatim">write</tt>s of
+ big file portions. The recieving of a large fragmented message may have
+ a specific implementation allowing the reciever to work with the partial
+ data as soon as it starts arriving and not having to wait for the whole
+ message to be transmitted and buffered. Research is yet to be done on
+ this specific subject.
+ </p>
+ <h3 id="auto-13">2.7<span style="margin-left: 1em"></span>Permissions</h3>
+ <p>
+ For each attached client the server may keep track of associated
+ permissions, and accept or reject requests according to those
+ permissions. The client may use an authentication command to gain
+ supplementary privileges on the server's ressources. The client may
+ request a token to delegate it's privileges on a given object to another
+ client. Advanced right management functionnalities are to be discussed.
+ </p>
+ <h3 id="auto-14">2.8<span style="margin-left: 1em"></span>Reliability concerns</h3>
+ <p>
+ The NARP protocol relies on the fact that when transmitting a message,
+ the other end will recieve it. It is nevertheless recommended that NARP
+ implementations support the repeating of messages if an expected
+ acknowlegment has not arrived after a given delay.
+ </p>
+ <h3 id="auto-15">2.9<span style="margin-left: 1em"></span>Example NARP servers</h3>
+ <h4 id="auto-16">2.9.1<span style="margin-left: 1em"></span>Virtual NARP server (i.e. NARP
+ router)</h4>
+ <p>
+ This server implements a namespace where any client may create an empty
+ object and serve connections to it. Additionnaly, the server may
+ implement the possibility to create virtual files, virtual directories,
+ FIFO queues, etc.
+ </p>
+ <p>
+ This server may be connected to other virtual NARP servers in order to
+ provide a global namespace accessible to all. Each virtual NARP server
+ acts as an endpoint into the network and may have functionnality for
+ routing the communications to objects to the clients that serve them.
+ </p>
+ <h4 id="auto-17">2.9.2<span style="margin-left: 1em"></span>NARP file server</h4>
+ <p>
+ This server simply implements access to a filesystem : listed ressources
+ are the same as the files present in a served directory, each of these
+ implements the filing protocol (served directly by the file server), and
+ the creation of files/directories may also be implemented.
+ </p>
+ <h4 id="auto-18">2.9.3<span style="margin-left: 1em"></span>NARP terminal/GUI server</h4>
+ <p>
+ Clients may create objects on the server ; each of these objects
+ correspond to a GUI window. Two interfaces may be implemented : text IO
+ (terminal) and graphical interaction. Advanced terminal interaction
+ features may be implemented at the protocol level, such as
+ auto-completion of commands or of text being edited&hellip;
+ </p>
+ <p>
+ Suggestion for a third kind of window : the data sent by the client
+ corresponds to a description of the scene in a given markup language and
+ the server does the rendering. The client can also subscribed to events
+ such as clicking on an item or entering text. This possibility is to be
+ explored.
+ </p>
+ <h4 id="auto-19">2.9.4<span style="margin-left: 1em"></span>NARP e-mail and newsgroup server</h4>
+ <p>
+ Several features to be implemented:
+ </p>
+ <ul>
+ <li>
+ <p>
+ user login and private user mailboxes
+ </p>
+ </li>
+ <li>
+ <p>
+ bridge to standard SMTP/POP3/IMAP services
+ </p>
+ </li>
+ <li>
+ <p>
+ private threads of conversation with access rights (the users don't
+ each have a copy of the thread)
+ </p>
+ </li>
+ <li>
+ <p>
+ synchronization between many servers
+ </p>
+ </li>
+ <li>
+ <p>
+ public discussion forums
+ </p>
+ </li>
+ </ul>
+ <h4 id="auto-20">2.9.5<span style="margin-left: 1em"></span>NARP chat server</h4>
+ <ul>
+ <li>
+ <p>
+ user login and status notification
+ </p>
+ </li>
+ <li>
+ <p>
+ online and offline private messaging
+ </p>
+ </li>
+ <li>
+ <p>
+ public chat rooms, chat room logging independently of user being
+ online or offline
+ </p>
+ </li>
+ <li>
+ <p>
+ bridging and synchronization between many servers
+ </p>
+ </li>
+ </ul>
+ <h4 id="auto-21">2.9.6<span style="margin-left: 1em"></span>NARP applicative server</h4>
+ <p>
+ TODO&hellip;
+ </p>
+ <h2 id="auto-22">3<span style="margin-left: 1em"></span>Specifics of the NARP protocol</h2>
+ <h3 id="auto-23">3.1<span style="margin-left: 1em"></span>Protocol description format</h3>
+ <p>
+ A protocol message is given in the following form:
+ </p>
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid">element type</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">element type</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">&hellip;</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">element type</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">element description</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">element description</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">&hellip;</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">element description</td>
+ </tr></tbody>
+ </table>
+ <p>
+ The following element types apply:
+ </p>
+ <ul>
+ <li>
+ <p>
+ int16, int32, int64 : 16-bit, 32-bit or 64-bit little-endian
+ integers
+ </p>
+ </li>
+ <li>
+ <p>
+ str : a string, prefixed by a 16-bit length header
+ </p>
+ </li>
+ <li>
+ <p>
+ arr(<var>T</var>) : an array of <var>T</var>'s (where <var>T</var>
+ is another element type), prefixed by a 16-bit length header
+ </p>
+ </li>
+ <li>
+ <p>
+ * (for the last element) : consider all the rest of the message as a
+ byte string
+ </p>
+ </li>
+ </ul>
+ <h3 id="auto-24">3.2<span style="margin-left: 1em"></span>Basic message format</h3>
+ <p>
+ The basic format of a message is :
+ </p>
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid">int16</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int16</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">*</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">message size</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">message type</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">payload</td>
+ </tr></tbody>
+ </table>
+ <p>
+ We will abbreviate by &ldquo;header&rdquo; the first 32 bits (4 bytes)
+ of the message. The list of message types is given in section <a href="#type-nums">3.7.1</a>.
+ </p>
+ <p>
+ Messages for communication with an attached ressource will have the
+ following format :
+ </p>
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid">int16</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int16</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">*</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">message size</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">message type</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">ressource descriptor (handle)</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">payload</td>
+ </tr></tbody>
+ </table>
+ <p>
+ Many client messages awating a response will have a message ID included
+ ; this message ID is an arbitrary number generated by the client and
+ used by the server when giving its response. The header then looks like
+ this:
+ </p>
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid">int16</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int16</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">*</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">message size</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">message type</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">message ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">payload</td>
+ </tr></tbody>
+ </table>
+ <h3 id="auto-25">3.3<span style="margin-left: 1em"></span>Message list for core NARP protocol</h3>
+ <p>
+ Client messages have an up arrow (<var>&uarr;</var>) next to their name,
+ while server messages have a down arrow (<var>&darr;</var>).
+ </p>
+ <p>
+ The core NARP protocol is meant for small size and rapidity (so that
+ many layers can be encapsulated with minimal overhead), therefore no
+ acknowlegment is to be sent for recursive send/recieve messages. Other
+ messages usually imply some kind of action or getting of information,
+ therefore an acknowlegment or an error is usually sent as a response.
+ </p>
+ <p>
+ <a id="auto-26"></a><h5>Hello<var>&uarr;</var><var>&darr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">arr(int32)</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">version</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">list of needed/provided interfaces</td>
+ </tr></tbody>
+ </table>
+
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ When a NARP connection is established, the client is always the
+ first to send a <strong>Hello</strong> message. The object may then
+ respond either with a <strong>Hello</strong> message indicating that
+ the requested interfaces can be provided, or with an
+ <strong>Error</strong> message. The two common error causes are
+ <em>interface not implemented</em> and <em>incompatible
+ versions</em>.
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ For interface numbers : see table in section <a href="#interface-nums">3.7.3</a>.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-27"></a><h5>Error<var>&darr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Generic error response message for any operation.
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">error ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">error string</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Common error IDs are specified in section <a href="#error-nums">3.7.2</a>.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-28"></a><h5>Ack<var>&darr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Generic acknowlegment message for commands that require it. An
+ acknowlege implies the command has been sucessfully executed
+ (otherwise an error message is sent).
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-29"></a><h5>Stat<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">filename</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ The request ID is an ID decided by the client so that it can
+ identify the answer.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-30"></a><h5>StatR<var>&darr;</var></h5>Response to the
+ <strong>Stat</strong> message.
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">arr(int32)</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">implemented interface</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Common interface numbers are to be found in section <a href="#interface-nums">3.7.3</a>.
+ </p>
+ <p>
+ If a <strong>Stat</strong> query on an object gives a certain list
+ of interfaces, then when connecting to the object at least all these
+ interfaces must be included in the server's <strong>Hello</strong>
+ message as supported interfaces.
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Note that some interface numbers correspond to actions that can be
+ done on the object from the connection where the object exists (e.g.
+ : symbolic link, directory), and others correspond to actions that
+ can be performed after attaching to the object (e.g. file, terminal,
+ &hellip;)
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-31"></a><h5>List<var>&uarr;</var></h5>
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">first entry number</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">number of entries requested</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">base path string</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+ <a id="auto-32"></a><h5>ListR<var>&darr;</var></h5>Response to the
+ <strong>List</strong> message.
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ One message is passed for each entry in the requested range:
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">entry number</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">entry name</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ After the directory has finished being enumerated, a supplementary
+ entry is given with entry number the last valid entry number plus
+ one and an empty entry name. This supplementary entry is only given
+ if its (ficious) entry number is included in the range requested by
+ the client.
+ </p>
+ </div>
+ </p>
+ <p>
+ Possible extension : combine List and Stat so that when the answer to
+ List is given, information is also given on the object's implemented
+ interfaces.
+ </p>
+ <p>
+ <a id="auto-33"></a><h5>Attach<var>&uarr;</var></h5>
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">filename</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+ <a id="auto-34"></a><h5>Attached<var>&darr;</var></h5>Response to the
+ <strong>Attach</strong> command.
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">handle</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ (the handle, ie the ressource descriptor, is attributed by the
+ server)
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-35"></a><h5>Send<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">*</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">handle</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">payload</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ This message does not expect a response.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-36"></a><h5>Recieve<var>&darr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Spontaneous server message indicating some data is sent by an
+ attached ressource. This message does not expect a response.
+ </p>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">*</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">handle</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">payload</td>
+ </tr></tbody>
+ </table>
+ </div>
+ </p>
+ <p>
+ <a id="auto-37"></a><h5>Detach<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">handle</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ This message does not expect a response.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-38"></a><h5>Detached<var>&darr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Spontaneous server message indicating the object has been detached.
+ </p>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">handle</td>
+ </tr></tbody>
+ </table>
+ </div>
+ </p>
+ <p>
+ <a id="auto-39"></a><h5><strong>Create<var>&uarr;</var></strong></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">arr(int32)</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">needed interfaces</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">path</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ A create request is accompanied with a list of needed interfaces
+ that direct the server into creating the corresponding type of
+ object (e.g. an empty object to be served, a directory, a file,
+ &hellip;)
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-40"></a><h5>Created<var>&darr;</var></h5>Response to the
+ <strong>Create</strong> command.
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">arr(int32)</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">implemented interfaces</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Signals that the object has been created, and has corresponding
+ interfaces associated to it.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-41"></a><h5>Delete<var>&uarr;</var><tt class="verbatim"></tt></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">path</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ This message expects a standard <strong>Ack</strong> response
+ message.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-42"></a><h5>Link<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">destination path</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">link path</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ This message expects a standard <strong>Ack</strong> response
+ message.
+ </p>
+ <p>
+ Semantics of the link object:
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <ul>
+ <li>
+ <p>
+ attaching or serving on this objects corresponds to resolving
+ the linked path and attaching/serving on the linked object
+ </p>
+ </li>
+ <li>
+ <p>
+ stating the link will stat the linked object and add as an
+ implemented interface the &ldquo;this is a symlink&rdquo;
+ information
+ </p>
+ </li>
+ <li>
+ <p>
+ directory listings follow links
+ </p>
+ </li>
+ <li>
+ <p>
+ deleting the link will not delete the original file but only the
+ link
+ </p>
+ </li>
+ </ul>
+ </div>
+ </p>
+ <p>
+ <a id="auto-43"></a><h5>ReadLink<var>&uarr;</var></h5>
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">path</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+ <a id="auto-44"></a><h5>ReadLinkR<var>&darr;</var></h5>Response to the
+ <strong>ReadLink</strong> message.
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">link description</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ This will only return the first level of linking, ie the link data
+ directly associated to the link object.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-45"></a><h5>Rename<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">original path</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">new path</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ This message expects a standard <strong>Ack</strong> response
+ message.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-46"></a><h5>Serve<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">array(int32)</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">path</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">announced interfaces</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ This message is a request for the client to be a reverse server to
+ an object. The response message to this message is an
+ <strong>Attached</strong> message. The handle attributed to the
+ served object is known as the <em>server handle</em> and is used in
+ the <strong>Incoming</strong> and <strong>Detach</strong> messages.
+ </p>
+ <p>
+ To stop serving an object, the client simply sends a
+ <strong>Detach</strong> command on the server handle. The semantics
+ is that all connections that have been openned through the
+ reverse-served object are preserved when the object stops being
+ served, and an individual <strong>Detach</strong> message must be
+ sent to all of them if we want to close them.
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ The <em>announced interfaces</em> serves to answer
+ <strong>Stat</strong> messages on the object while we are serving
+ it.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-47"></a><h5>Incoming<var>&darr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">server handle</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">client hande</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ This message is sent by the server when another client wishes to
+ attach to an object reverse-served by this client. The server handle
+ is the one given as a response to the <strong>Serve</strong>
+ message. The client handle is a handle associated to the connection.
+ The reverse server may reject the connection by issuing a
+ <strong>Detach</strong> command on the client handle, or may accept
+ it using the <strong>Accept</strong> message given below.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-48"></a><h5>Accept<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">client handle</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Once a connection has been accepted, the reverse server may at any
+ moment close it by sending a <strong>Detach</strong> command on the
+ corresponding client handle.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-49"></a><h5>Unbox<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">outer handle</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">inner handle</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Consider the handle <em>outer handle</em> as a NARP protocol
+ service, and associate a handle in the outer layer to the handle of
+ the inner layer with handle <em>inner handle</em>.
+ </p>
+ <p>
+ Example : in connection A we have a connection open on handle 5
+ which contains NARP data that we will call B, and in connection B we
+ have another connection open on handle 7. Issuing a Unbox(id, 5, 7)
+ request on A will lead to the server creating a handle (say 12)
+ where sending corresponds to sending a message to handle 7 on
+ connection B, and such that all messages recieved on handle 5 (ie on
+ connection B) are filtered and messages whose destination is handle
+ 7 on connection B are removed from the stream and issued on handle
+ 12 of connection A instead.
+ </p>
+ <p>
+ The answer to such a request is an <strong>Attached</strong>
+ response giving a handle to the unboxed connection.
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Systematically unboxing open connections may lead in some cases to
+ the network infrastructure being able to do simplifications in the
+ interconnections. In other cases it may result to useless overhead
+ on the server side : in such a case the server may refuse an unbox
+ request.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-50"></a><h5>Plug<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">handle A</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">handle B</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Ask the server to redirect all messages recieved on handle A to
+ handle B and all mesages recieved on handle B to handle A. The
+ messages recieved on either handle are not sent to the client
+ anymore.
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ The answer messages are standard
+ <strong>Ack</strong>/<strong>Error</strong> messages.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-51"></a><h5>Unplug<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">request ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">handle A</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">handle B</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Undoes a plugging.
+ </p>
+ </div>
+ </p>
+ <h3 id="auto-52">3.4<span style="margin-left: 1em"></span>Big message protocol</h3>
+ <p>
+ To be defined. Is it really usefull? What role exactly does it have? Can
+ it implement repetition in the case where the message hasn't been
+ acknowledge? &hellip;
+ </p>
+ <h3 id="auto-53">3.5<span style="margin-left: 1em"></span>Authentification and rights managment
+ commands</h3>
+ <p>
+ <a id="auto-54"></a><h5>Authenticate<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">*</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">message ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">authentification method</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">authentification data</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Used to gain access using credentials (user/password, token,
+ &hellip;). Response messages are standard <strong>Ack</strong> on
+ success or <strong>Error</strong> on failure. Autentification
+ methods include :
+ </p>
+ </div>
+ <div style="margin-left: 35.145870328812px">
+ <ul>
+ <li>
+ <p>
+ 1 : user + password
+ </p>
+ </li>
+ <li>
+ <p>
+ 2 : token
+ </p>
+ </li>
+ </ul>
+ </div>
+ </p>
+ <p>
+ <a id="auto-55"></a><h5>NewToken<var>&uarr;</var></h5>
+ </p>
+ <p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">message ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">path</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ Requests the server to create an authentication token for accessing
+ a given object with the privileges of the connected client. Once the
+ token has been returned, it may be transmitted to another client so
+ that that client will use it to gain same access to the object.
+ </p>
+ </div>
+ </p>
+ <p>
+ <a id="auto-56"></a><h5>NewTokenR<var>&darr;</var></h5>Response to the
+ <strong>NewToken</strong> message.
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.1em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">int32</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-top: 1px solid">str</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center; border-left: 1px solid">header</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">message ID</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; text-align: center">token</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+ TODO : request account creation, manage user groups and ACLs, &hellip;
+ </p>
+ <h3 id="auto-57">3.6<span style="margin-left: 1em"></span>TODO</h3>
+ <ul>
+ <li>
+ <p>
+ file protocol
+ </p>
+ <p>
+
+ </p>
+ </li>
+ <li>
+ <p>
+ system protocols (see section on OS design using NARP)
+ </p>
+ </li>
+ <li>
+ <p>
+ UI protocols (terminal, GUI)
+ </p>
+ </li>
+ <li>
+ <p>
+ communication protocols (mail, IM)
+ </p>
+ </li>
+ </ul>
+ <h3 id="auto-58">3.7<span style="margin-left: 1em"></span>Table of IDs</h3>
+ <p>
+ The tables presented in this section give the number associated to the
+ message types. These tables are the reference on the subject ; any
+ information found somewhere else is wrong if it is not the same as found
+ here. This is for protocol version 1.
+ </p>
+ <h4 id="auto-59"><a id="type-nums"></a>3.7.1<span style="margin-left: 1em"></span>Message types</h4>
+ <p>
+ <a id="auto-60"></a><h5>Base protocol</h5>
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -6.6em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid; border-top: 1px solid">message</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid"><var>&uarr;</var> id</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid"><var>&darr;</var> id</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid; border-top: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid">message</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid"><var>&uarr;</var> id</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid"><var>&darr;</var> id</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Hello</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">0</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10000</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>Stat</strong> / <strong>StatR</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10010</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Error</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10001</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>List</strong> / <strong>ListR</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">11</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10011</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Ack</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10002</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>Create</strong> / <strong>Created</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">12</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10012</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>Delete</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">13</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Attach</strong> / <strong>Attached</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">5</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10005</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>Rename</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">14</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Send</strong> / <strong>Recieve</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">6</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10006</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>Link</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">15</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Detach</strong> / <strong>Detached</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">7</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10007</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>ReadLink</strong> /
+ <strong>ReadLinkR</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">16</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10016</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Serve</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">8</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Incoming</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10008</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>Unbox</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">20</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Accept</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">9</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>Plug</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">21</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 0 solid; border-bottom: 0 solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>Unplug</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">22</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr></tbody>
+ </table>
+ </div>
+ <p>
+ <a id="auto-61"></a><h5>Authentication &amp; privileges</h5>
+ </p>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -1.65em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid; border-top: 1px solid">message</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid"><var>&uarr;</var> id</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid"><var>&darr;</var> id</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>Authenticate</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">30</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"><strong>NewToken</strong> /
+ <strong>NewTokenR</strong></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">31</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">10031</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <h4 id="auto-62"><a id="error-nums"></a>3.7.2<span style="margin-left: 1em"></span>Error messages</h4>
+ <div style="margin-left: 35.145870328812px">
+ <table style="display: inline; vertical-align: -6.05em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid; border-top: 1px solid">id</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid">cause</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">1</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">Incompatible versions</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">2</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">Command/interface not implemented</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">3</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">Invalid request (e.g. : out of bounds)</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">4</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">Invalid handle</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">5</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">Attach request rejected</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">6</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">Action impossible because object is in use (cannot
+ delete, &hellip;)</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">7</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">No such object (invalid path)</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">8</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">Could not resolve link</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">9</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">Incorrect credentials</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">10</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">Unauthorized</td>
+ </tr></tbody>
+ </table>
+ </div>
+ <h4 id="auto-63">3.7.3<span style="margin-left: 1em"></span>Object interfaces<a id="interface-nums"></a></h4>
+ <div style="margin-left: 35.145870328812px">
+ <p>
+ <table style="display: inline; vertical-align: -7.15em">
+ <tbody><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid; border-top: 1px solid">id</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid">name</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-top: 1px solid">must implement messages</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">0</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">servable</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>Serve</strong>, <strong>Accept</strong>,
+ <strong>Incoming</strong></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">1</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">enumerable</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>List</strong>, <strong>ListR</strong></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">2</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">is symlink</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"><strong>ReadLink</strong>,
+ <strong>ReadLinkR</strong></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">9</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">non-NARP inside</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">once attached, inside data is arbitrary</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">10</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">NARP service</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">once attached, inside data is a NARP service (ie has
+ objects, &hellip;)</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">11</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">NARP unbox</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">once attached, <strong>Unbox</strong> command
+ supported</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">12</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">NARP plug</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">once attached, <strong>Plug</strong> and
+ <strong>Unplug</strong> commands supported</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid"></td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">20</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">file</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">once attached, file semantics</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">21</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">terminal</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">once attached, terminal semantics</td>
+ </tr><tr>
+ <td style="border-right: 1px solid; border-bottom: 1px solid; border-left: 1px solid">22</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">graphics window</td>
+ <td style="border-right: 1px solid; border-bottom: 1px solid">once attached, GUI semantics</td>
+ </tr></tbody>
+ </table>
+
+ </p>
+ </div>
+ <p>
+ <a id="auto-64"></a><h5>Servable</h5>This interface specifies that the object is
+ currently an empty object waiting for someone to issue a
+ <strong>Serve</strong> command on it, providing it with an
+ implementation of some interfaces.
+ </p>
+ <p>
+ <a id="auto-65"></a><h5>non-NARP inside</h5>This interfaces indicates that once
+ attached to the object, the messages sent/recieved to it are not
+ supposed to be NARP format but any arbitrary format. If this interface
+ is not specified, then it is expected that the messages transmitted will
+ follow the general NARP protocol (message format, standard
+ hello/ack/error messages).
+ </p>
+ <p>
+ <a id="auto-66"></a><h5>NARP service</h5>This interface indicates that once
+ attached to the object, one can have access to a new NARP namespace
+ where at least the following operations are supported :
+ <strong>Stat</strong>, <strong>Attach</strong>, <strong>Send</strong>,
+ <strong>Recieve</strong>, <strong>Detach</strong>. Additionnal messages
+ may or may not be supported.
+ </p>
+ <h2 id="auto-67">4<span style="margin-left: 1em"></span>Architecture of a NARP implementation in
+ OCaml or Haskell</h2>
+ <p>
+ An asynchronous implementation can be easily programmed in functionnal
+ languages such as OCaml or Haskell, using closures as continuations for
+ <em>what to do when a (response) message arrives</em>.
+ </p>
+ <p>
+ TODO
+ </p>
+ <h2 id="auto-68">5<span style="margin-left: 1em"></span>Using NARP to design an Operating System</h2>
+ <p>
+ When designing the NARP protocol, we had in mind that it would be
+ possible to use it in a new operating system design at many levels :
+ access to devices, process management, memory management, filesystems,
+ IPC, GUI, &hellip;
+ </p>
+ <p>
+ Kernel helpers could be developped so that a part of the NARP
+ multiplexing and demultiplexing takes place in kernel land, before
+ messages are passed to userspace. For instance, this would allow the
+ simplification of useless mux-demux chains taking place on the same
+ machine. The mux-demux helper can be implemented via the
+ <strong>Unbox</strong> protocol message, handled at the level of the
+ root stream of NARP communication with the kernel. Another possible
+ helper would be to map a virtual memory region to a NARP ressource
+ implementing a standard filing protocol, much like memory mapped files
+ in standard OSes (only this would work with arbitrary ressources).
+ </p>
+ <p>
+ In this section we will develop on a concrete proposal for a NARP-based
+ operating system.
+ </p>
+ <h3 id="auto-69">5.1<span style="margin-left: 1em"></span>Architecture of the OS</h3>
+ <p>
+ The basic primitive of the system being message-passing, the system
+ looks a lot like a micro-kernel. Only the message format has a complex
+ semantic and the communication layer is not really &ldquo;simple&rdquo;.
+ Furthermore, the system has device drivers, file system and networking
+ running as kernel-mode processes, making the kernel more monolithic (but
+ still having a micro-kernel spirit). It should be easy to make any user
+ mode process run as a kernel mode process instead, for the sake of
+ performance (eg : graphical server &amp; compositor).
+ </p>
+ <p>
+ The kernel land is divided in three major parts, with strict dependency
+ order:
+ </p>
+ <ul>
+ <li>
+ <p>
+ Level 0 : System ressource managment : physical memory, virtual
+ memory, hardware interaction (IRQ, v86), debug output
+ </p>
+ </li>
+ <li>
+ <p>
+ Level 1 : Scheduler, IPC &amp; NARP core server : builds on top of
+ level 0, adds support for processes and communication between them
+ restricted to NARP protocol data.
+ </p>
+ </li>
+ <li>
+ <p>
+ Level 2 : System processes : hardware, file systems, network,
+ &hellip; (may access level 0 and level 1 features)
+ </p>
+ </li>
+ </ul>
+ <p>
+ User processes are restricted to syscalls that call level 1 primitives.
+ </p>
+ <p>
+ Here are a few basic principles for the design of these three levels :
+ </p>
+ <ul>
+ <li>
+ <p>
+ Level 2 processes may not communicate directly nor share memory :
+ they must go through level 0 and level 1 primitives to achieve such
+ a goal. Each level 2 process has a separate heap, which is
+ completely freed when the process dies. Level 2 processes do not use
+ separate virtual memory spaces : since the kernel memory space is
+ mapped in all page directories, a level 2 process may run with any
+ page directory.
+ </p>
+ <p>
+ Benefits : critical system parts are restricted to level 0 and level
+ 1. Level 2 components may leak or crash with less consequences.
+ </p>
+ </li>
+ <li>
+ <p>
+ All synchronization &amp; locking is handle by level 1, except for
+ level 0 that must implement its own locking devices (since it cannot
+ rely on level 1).
+ </p>
+ <p>
+ Benefits : no complex synchronization in most of the code (which is
+ either level 2 or userland), only simple message passing and waiting
+ for stuff to happen
+ </p>
+ </li>
+ <li>
+ <p>
+ No concept of &ldquo;threads&rdquo; : system processes are actually
+ kernel threads, but we call them processes since they use separate
+ parts of memory. Userlands processes cannot spawn multiple threads
+ of execution either : they must fork and communicate through NARP if
+ they want to do so (eg: launching an expensive communication in the
+ background).
+ </p>
+ <p>
+ (since fork is a complicated system call, and features such as
+ copy-on-write depend on processes using different paging
+ directories, the fork system call is accessible only to userland
+ processes : level 2 processes may not fork, but only create new
+ processes)
+ </p>
+ </li>
+ <li>
+ <p>
+ Level 1 also has a memory heap ; it is used with <tt class="verbatim">core_malloc/core_free</tt>.
+ Level 2 proceses use standard <tt class="verbatim">malloc/free</tt>, which are
+ modified to act on the heap of the current process.
+ </p>
+ </li>
+ <li>
+ <p>
+ Each process (system or user) has a <em>mailbox</em>, ie a queue of
+ incoming NARP messages waiting to be transferred. The mailbox has a
+ maximum <em>size</em> (buffer size), and a <em>send</em> call may
+ fail with a <em>no space left in queue</em> error. This is the only
+ possible failure for a <em>send</em> call.
+ </p>
+ <p>
+ System processes (level 2) spend most of their time in <em>waiting
+ mode</em> ; they may be waked up by either recieving a NARP messsage
+ or by a hardware event. Therefore the <em>wait_for_event</em>
+ function that composes the main loop may return either : <em>a
+ message was recieved</em> or <em>a system event happenned</em>. If
+ the reason is <em>a message was recieved</em>, the process is free
+ not to read the message immediately.
+ </p>
+ <p>
+ On the other hand, user processes can wait for only one thing :
+ recieving a NARP message. Each user process has a <em>message
+ zone</em> in its memory space, and the <em>wait for message</em>
+ function just copies the first message of the mailbox into this zone
+ (overwriting whatever was there before) and returns control to the
+ process (returning the length of the message).
+ </p>
+ </li>
+ <li>
+ <p>
+ Handling of IRQs : some hardware stuff requires action as soon as
+ the interrupt is fired, therefore a specifi IRQ handler may be used.
+ Such a handler must do as little as possible, and when it is done
+ signal level 1 that an IRQ has happenned (it may add specific data
+ to the &ldquo;IRQ happenned&rdquo; message). Level 1 adds a message
+ to the queue of the recipient process (if there is one) and returns
+ immediately : the IRQ handler must leave as soon as possible. An IRQ
+ is handled on whatever stack is currently used, and the IF flag is
+ constantly off while the IRQ handler is running. The timer IRQ is
+ the only one that behaves differently, since it has to trigger a
+ task switch.
+ </p>
+ </li>
+ </ul>
+ <h3 id="auto-70">5.2<span style="margin-left: 1em"></span>Steps of the developpment of the OS</h3>
+ <ol>
+ <li>
+ <p>
+ Develop level 0 completely and with cleanest possible design
+ </p>
+ </li>
+ <li>
+ <p>
+ Develop level 1 with only basic funcionnality
+ </p>
+ </li>
+ <li>
+ <p>
+ Develop some basic applications in level 2 : display, keyboard, mini
+ kernel shell, mini file system, &hellip;
+ </p>
+ </li>
+ <li>
+ <p>
+ Improve level 1 with more complex stuff ; try to quickly attain a
+ complete level 1
+ </p>
+ </li>
+ <li>
+ <p>
+ Work on the rest of the stuff
+ </p>
+ </li>
+ </ol>
+ </body>
+</html> \ No newline at end of file
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new file mode 100644
index 0000000..231858b
--- /dev/null
+++ b/doc/spec-2.pdf
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