<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html xmlns:fn="http://www.w3.org/2005/02/xpath-functions"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <link rel="stylesheet" href="../../../../doc/otp_doc.css" type="text/css"> <title>Erlang -- diameter_codec(3)</title> </head> <body bgcolor="white" text="#000000" link="#0000ff" vlink="#ff00ff" alink="#ff0000"><div id="container"> <script id="js" type="text/javascript" language="JavaScript" src="../../../../doc/js/flipmenu/flipmenu.js"></script><script id="js2" type="text/javascript" src="../../../../doc/js/erlresolvelinks.js"></script><script language="JavaScript" type="text/javascript"> <!-- function getWinHeight() { var myHeight = 0; if( typeof( window.innerHeight ) == 'number' ) { //Non-IE myHeight = window.innerHeight; } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) { //IE 6+ in 'standards compliant mode' 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href="../../../../doc/index.html">Top</a></small><p><strong>Diameter</strong><br><strong>Reference Manual</strong><br><small>Version 1.3</small></p> <br><a href="javascript:openAllFlips()">Expand All</a><br><a href="javascript:closeAllFlips()">Contract All</a><p><small><strong>Table of Contents</strong></small></p> <ul class="flipMenu"> <li id="no" title="diameter " expanded="false">diameter<ul> <li><a href="diameter.html"> Top of manual page </a></li> <li title="add_transport-2"><a href="diameter.html#add_transport-2">add_transport/2</a></li> <li title="call-4"><a href="diameter.html#call-4">call/4</a></li> <li title="origin_state_id-0"><a href="diameter.html#origin_state_id-0">origin_state_id/0</a></li> <li title="remove_transport-2"><a href="diameter.html#remove_transport-2">remove_transport/2</a></li> <li title="service_info-2"><a href="diameter.html#service_info-2">service_info/2</a></li> <li title="services-0"><a href="diameter.html#services-0">services/0</a></li> <li title="session_id-1"><a href="diameter.html#session_id-1">session_id/1</a></li> <li title="start-0"><a href="diameter.html#start-0">start/0</a></li> <li title="start_service-2"><a href="diameter.html#start_service-2">start_service/2</a></li> <li title="stop-0"><a href="diameter.html#stop-0">stop/0</a></li> <li title="stop_service-1"><a href="diameter.html#stop_service-1">stop_service/1</a></li> <li title="subscribe-1"><a href="diameter.html#subscribe-1">subscribe/1</a></li> <li title="unsubscribe-1"><a href="diameter.html#unsubscribe-1">unsubscribe/1</a></li> </ul> </li> <li title="diameterc"><a href="diameterc.html">diameterc</a></li> <li id="no" title="diameter_app " expanded="false">diameter_app<ul> <li><a href="diameter_app.html"> Top of manual page </a></li> <li title="Mod:peer_up-3"><a href="diameter_app.html#Mod:peer_up-3">Mod:peer_up/3</a></li> <li title="Mod:peer_down-3"><a href="diameter_app.html#Mod:peer_down-3">Mod:peer_down/3</a></li> <li title="Mod:pick_peer-4"><a href="diameter_app.html#Mod:pick_peer-4">Mod:pick_peer/4</a></li> <li title="Mod:prepare_request-3"><a href="diameter_app.html#Mod:prepare_request-3">Mod:prepare_request/3</a></li> <li title="Mod:prepare_retransmit-3"><a href="diameter_app.html#Mod:prepare_retransmit-3">Mod:prepare_retransmit/3</a></li> <li title="Mod:handle_answer-4"><a href="diameter_app.html#Mod:handle_answer-4">Mod:handle_answer/4</a></li> <li title="Mod:handle_error-4"><a href="diameter_app.html#Mod:handle_error-4">Mod:handle_error/4</a></li> <li title="Mod:handle_request-3"><a href="diameter_app.html#Mod:handle_request-3">Mod:handle_request/3</a></li> </ul> </li> <li id="loadscrollpos" title="diameter_codec " expanded="true">diameter_codec<ul> <li><a href="diameter_codec.html"> Top of manual page </a></li> <li title="decode-2"><a href="diameter_codec.html#decode-2">decode/2</a></li> <li title="encode-2"><a href="diameter_codec.html#encode-2">encode/2</a></li> </ul> </li> <li title="diameter_dict"><a href="diameter_dict.html">diameter_dict</a></li> <li id="no" title="diameter_make " expanded="false">diameter_make<ul> <li><a href="diameter_make.html"> Top of manual page </a></li> <li title="codec-2"><a href="diameter_make.html#codec-2">codec/2</a></li> </ul> </li> <li id="no" title="diameter_transport " expanded="false">diameter_transport<ul> <li><a href="diameter_transport.html"> Top of manual page </a></li> <li title="Mod:start-3"><a href="diameter_transport.html#Mod:start-3">Mod:start/3</a></li> </ul> </li> <li id="no" title="diameter_tcp " expanded="false">diameter_tcp<ul> <li><a href="diameter_tcp.html"> Top of manual page </a></li> <li title="start-3"><a href="diameter_tcp.html#start-3">start/3</a></li> </ul> </li> <li id="no" title="diameter_sctp " expanded="false">diameter_sctp<ul> <li><a href="diameter_sctp.html"> Top of manual page </a></li> <li title="start-3"><a href="diameter_sctp.html#start-3">start/3</a></li> </ul> </li> </ul> </div></div> <div id="content"> <div class="innertube"> <!-- refpage --><center><h1>diameter_codec</h1></center> <h3>MODULE</h3> <div class="REFBODY">diameter_codec</div> <h3>MODULE SUMMARY</h3> <div class="REFBODY">Decode and encode of Diameter messages.</div> <h3>DESCRIPTION</h3> <div class="REFBODY"><p> <p> Incoming Diameter messages are decoded from binary() before being communicated to <span class="bold_code"><a href="diameter_app.html">diameter_app(3)</a></span> callbacks. Similarly, outgoing Diameter messages are encoded into binary() before being passed to the appropriate <span class="bold_code"><a href="diameter_transport.html">diameter_transport(3)</a></span> module for transmission. The functions in this module implement this encode/decode.</p> <div class="note"> <div class="label">Note</div> <div class="content"><p> <p> Calls to this module are made by diameter itself as a consequence of configuration passed to <span class="bold_code"><a href="diameter.html#start_service-2">diameter:start_service/2</a></span>. The encode/decode functions may also be useful for other purposes (eg. test) but the diameter user does not need to call them explicitly when sending and receiving messages using <span class="bold_code"><a href="diameter.html#call-4">diameter:call/4</a></span> and the callback interface documented in <span class="bold_code"><a href="diameter_app.html">diameter_app(3)</a></span>.</p> </p></div> </div> <p> The <span class="bold_code"><a href="#header">header()</a></span> and <span class="bold_code"><a href="#packet">packet()</a></span> records below are defined in diameter.hrl, which can be included as follows.</p> <div class="example"><pre> -include_lib("diameter/include/diameter.hrl"). </pre></div> <p> Application-specific records are definied in the hrl files resulting from dictionary file compilation.</p> </p></div> <h3><a name="id75816">DATA TYPES</a></h3> <div class="REFBODY"> <p></p> <dl> <a name="integers"></a> <dt><strong><span class="code">uint8() = 0..255</span></strong></dt> <dt><strong><span class="code">uint24() = 0..16777215</span></strong></dt> <dt><strong><span class="code">uint32() = 0..4294967295</span></strong></dt> <dd> <p> 8-bit, 24-bit and 32-bit integers occurring in Diameter and AVP headers.</p> </dd> <a name="avp"></a> <dt><strong><span class="code">avp() = #diameter_avp{}</span></strong></dt> <dd> <p> The application-neutral representation of an AVP. Primarily intended for use by relay applications that need to handle arbitrary Diameter applications. A service implementing a specific Diameter application (for which it configures a dictionary) can manipulate values of type <span class="bold_code"><a href="#message">message()</a></span> instead.</p> <p> Fields have the following types.</p> <dl> <dt><strong><span class="code">code = uint32()</span></strong></dt> <dt><strong><span class="code">is_mandatory = boolean()</span></strong></dt> <dt><strong><span class="code">need_encryption = boolean()</span></strong></dt> <dt><strong><span class="code">vendor_id = uint32() | undefined</span></strong></dt> <dd> <p> Values in the AVP header, corresponding to AVP Code, the M flag, P flags and Vendor-ID respectivelty. A Vendor-ID other than <span class="code">undefined</span> implies a set V flag.</p> </dd> <dt><strong><span class="code">data = iolist()</span></strong></dt> <dd> <p> The data bytes of the AVP.</p> </dd> <dt><strong><span class="code">name = atom()</span></strong></dt> <dd> <p> The name of the AVP as defined in the dictionary file in question, or <span class="code">undefined</span> if the AVP is unknown to the dictionary file in question.</p> </dd> <dt><strong><span class="code">value = term()</span></strong></dt> <dd> <p> The decoded value of an AVP. Will be <span class="code">undefined</span> on decode if the data bytes could not be decoded or the AVP is unknown. The type of a decoded value is as document in <span class="bold_code"><a href="diameter_dict.html#DATA_TYPES">diameter_dict(4)</a></span>.</p> </dd> <dt><strong><span class="code">type = atom()</span></strong></dt> <dd> <p> The type of the AVP as specified in the dictionary file in question (or one it inherits). Possible types are <span class="code">undefined</span> and the Diameter types: <span class="code">OctetString</span>, <span class="code">Integer32</span>, <span class="code">Integer64</span>, <span class="code">Unsigned32</span>, <span class="code">Unsigned64</span>, <span class="code">Float32</span>, <span class="code">Float64</span>, <span class="code">Grouped</span>, <span class="code">Enumerated</span>, <span class="code">Address</span>, <span class="code">Time</span>, <span class="code">UTF8String</span>, <span class="code">DiameterIdentity</span>, <span class="code">DiameterURI</span>, <span class="code">IPFilterRule</span> and <span class="code">QoSFilterRule</span>.</p> </dd> </dl> </dd> <a name="dictionary"></a> <dt><strong><span class="code">dictionary() = module()</span></strong></dt> <dd> <p> The name of a generated dictionary module as generated by <span class="bold_code"><a href="diameterc.html">diameterc(1)</a></span> or <span class="bold_code"><a href="diameter_make.html#codec-2">diameter_make:codec/2</a></span>. The interface provided by a dictionary module is an implementation detail that may change.</p> </dd> <a name="header"></a> <dt><strong><span class="code">header() = #diameter_header{}</span></strong></dt> <dd> <p> The record representation of the Diameter header. Values in a <span class="bold_code"><a href="#packet">packet()</a></span> returned by <span class="bold_code"><a href="#decode-2">decode/2</a></span> are as extracted from the incoming message. Values set in an <span class="bold_code"><a href="#packet">packet()</a></span> passed to <span class="bold_code"><a href="#encode-2">encode/2</a></span> are preserved in the encoded binary(), with the exception of <span class="code">length</span>, <span class="code">cmd_code</span> and <span class="code">application_id</span>, all of which are determined by the <span class="bold_code"><a href="#dictionary">dictionary()</a></span> in question.</p> <div class="note"> <div class="label">Note</div> <div class="content"><p> <p> It is not necessary to set header fields explicitly in outgoing messages as diameter itself will set appropriate values. Setting inappropriate values can be useful for test purposes.</p> </p></div> </div> <p> Fields have the following types.</p> <dl> <dt><strong><span class="code">version = uint8()</span></strong></dt> <dt><strong><span class="code">length = uint24()</span></strong></dt> <dt><strong><span class="code">cmd_code = uint24()</span></strong></dt> <dt><strong><span class="code">application_id = uint32()</span></strong></dt> <dt><strong><span class="code">hop_by_hop_id = uint32()</span></strong></dt> <dt><strong><span class="code">end_to_end_id = uint32()</span></strong></dt> <dd> <p> Values of the Version, Message Length, Command-Code, Application-ID, Hop-by-Hop Identifier and End-to-End Identifier fields of the Diameter header.</p> </dd> <dt><strong><span class="code">is_request = boolean()</span></strong></dt> <dt><strong><span class="code">is_proxiable = boolean()</span></strong></dt> <dt><strong><span class="code">is_error = boolean()</span></strong></dt> <dt><strong><span class="code">is_retransmitted = boolean()</span></strong></dt> <dd> <p> Values correspoding to the R(equest), P(roxiable), E(rror) and T(Potentially re-transmitted message) flags of the Diameter header.</p> </dd> </dl> </dd> <a name="message"></a> <dt><strong><span class="code">message() = record() | list()</span></strong></dt> <dd> <p> The representation of a Diameter message as passed to <span class="bold_code"><a href="diameter.html#call-4">diameter:call/4</a></span> or returned from a <span class="bold_code"><a href="diameter_app.html#Mod:handle_request-3">handle_request/3</a></span> callback. The record representation is as outlined in <span class="bold_code"><a href="diameter_dict.html#MESSAGE_RECORDS">diameter_dict(4)</a></span>: a message as defined in a dictionary file is encoded as a record with one field for each component AVP. Equivalently, a message can also be encoded as a list whose head is the atom-valued message name (as specified in the relevant dictionary file) and whose tail is a list of <span class="code">{AvpName, AvpValue}</span> pairs.</p> <p> Another list-valued representation allows a message to be specified as a list whose head is a <span class="bold_code"><a href="#header">header()</a></span> and whose tail is an <span class="bold_code"><a href="#avp">avp()</a></span> list. This representation is used by diameter itself when relaying requests as directed by the return value of a <span class="bold_code"><a href="diameter_app.html#Mod:handle_request-3">handle_request/3</a></span> callback. It differs from the other other two in that it bypasses the checks for messages that do not agree with their definitions in the dictionary in question: messages are sent exactly as specified.</p> </dd> <a name="packet"></a> <dt><strong><span class="code">packet() = #diameter_packet{}</span></strong></dt> <dd> <p> A container for incoming and outgoing Diameter messages. Fields have the following types.</p> <dl> <dt><strong><span class="code">header = <span class="bold_code"><a href="#header">header()</a></span> | undefined</span></strong></dt> <dd> <p> The Diameter header of the message. Can be (and typically should be) <span class="code">undefined</span> for an outgoing message in a non-relay application, in which case diameter provides appropriate values.</p> </dd> <dt><strong><span class="code">avps = [<span class="bold_code"><a href="#avp">avp()</a></span>] | undefined</span></strong></dt> <dd> <p> The AVPs of the message. Ignored for an outgoing message if the <span class="code">msg</span> field is set to a value other than <span class="code">undefined</span>.</p> </dd> <dt><strong><span class="code">msg = <span class="bold_code"><a href="#message">message()</a></span> | undefined</span></strong></dt> <dd> <p> The incoming/outgoing message. For an incoming message, a record if the message can be decoded in a non-relay application, <span class="code">undefined</span> otherwise. For an outgoing message, setting a <span class="code">[<span class="bold_code"><a href="#header">header()</a></span> | <span class="bold_code"><a href="#avp">avp()</a></span>]</span> list is equivalent to setting the <span class="code">header</span> and <span class="code">avps</span> fields to the corresponding values.</p> <div class="warning"> <div class="label">Warning</div> <div class="content"><p> <p> A record-valued <span class="code">msg</span> field does <strong>not</strong> imply an absence of decode errors. The <span class="code">errors</span> field should also be examined.</p> </p></div> </div> </dd> <dt><strong><span class="code">bin = binary()</span></strong></dt> <dd> <p> The incoming message prior to encode or the outgoing message after encode.</p> </dd> <dt><strong><span class="code">errors = [5000..5999 | {5000..5999, avp()}]</span></strong></dt> <dd> <p> Errors detected at decode of an incoming message, as identified by a corresponding 5xxx series Result-Code (Permanent Failures). For an incoming request, these should be used to formulate an appropriate answer as documented for the <span class="bold_code"><a href="diameter_app.html#Mod:handle_request-3">handle_request/3</a></span> callback in <span class="bold_code"><a href="diameter_app.html">diameter_app(3)</a></span>. For an incoming answer, the <span class="bold_code"><a href="diameter.html#application_opt">diameter:application_opt()</a></span> <span class="code">answer_errors</span> determines the behaviour.</p> </dd> <dt><strong><span class="code">transport_data = term()</span></strong></dt> <dd> <p> An arbitrary term of meaning only to the transport process in question, as documented in <span class="bold_code"><a href="diameter_transport.html">diameter_transport(3)</a></span>.</p> </dd> </dl> </dd> </dl> </div> <h3>EXPORTS</h3> <p><a name="decode-2"><span class="bold_code">decode(Mod, Bin) -> Pkt</span></a><br></p> <div class="REFBODY"> <p>Types:</p> <div class="REFTYPES"> <span class="bold_code">Mod = <span class="bold_code"><a href="#dictionary">dictionary()</a></span></span><br> </div> <div class="REFTYPES"> <span class="bold_code">Bin = binary()</span><br> </div> <div class="REFTYPES"> <span class="bold_code">Pkt = <span class="bold_code"><a href="#packet">packet()</a></span></span><br> </div> </div> <div class="REFBODY"><p> <p> Decode a Diameter message.</p> </p></div> <p><a name="encode-2"><span class="bold_code">encode(Mod, Msg) -> Pkt</span></a><br></p> <div class="REFBODY"> <p>Types:</p> <div class="REFTYPES"> <span class="bold_code">Mod = <span class="bold_code"><a href="#dictionary">dictionary()</a></span></span><br> </div> <div class="REFTYPES"> <span class="bold_code">Msg = <span class="bold_code"><a href="#message">message()</a></span> | <span class="bold_code"><a href="#packet">packet()</a></span></span><br> </div> <div class="REFTYPES"> <span class="bold_code">Pkt = <span class="bold_code"><a href="#packet">packet()</a></span></span><br> </div> </div> <div class="REFBODY"><p> <p> Encode a Diameter message. </p> </p></div> <h3><a name="id76604">SEE ALSO</a></h3> <div class="REFBODY"> <p> <span class="bold_code"><a href="diameterc.html">diameterc(1)</a></span>, <span class="bold_code"><a href="diameter_app.html">diameter_app(3)</a></span>, <span class="bold_code"><a href="diameter_dict.html">diameter_dict(4)</a></span>, <span class="bold_code"><a href="diameter_make.html">diameter_make(3)</a></span></p> </div> </div> <div class="footer"> <hr> <p>Copyright © 2011-2012 Ericsson AB. All Rights Reserved.</p> </div> </div> </div></body> </html>