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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<section id="hdr_field" xmlns:xi="http://www.w3.org/2001/XInclude">
<sectioninfo>
<revhistory>
<revision>
<revnumber>$Revision$</revnumber>
<date>$Date$</date>
</revision>
</revhistory>
</sectioninfo>
<title>Structure <structname>hdr_field</structname></title>
<para>
The structure represents a header field of a SIP message. A header
field consist of <emphasis>name</emphasis> and
<emphasis>body</emphasis> separated by a double colon. For example:
"Server: SIP Express Router\r\n" is one header field. "Server" is
header field name and "SI Express Router\r\n" is header field body.
</para>
<para>
The structure is defined in file <filename>hf.h</filename> under
<filename>parser</filename> subdirectory.
</para>
<para>
<emphasis>Structure Declaration</emphasis>
<programlisting>
struct hdr_field {
int type; /* Header field type */
str name; /* Header field name */
str body; /* Header field body */
void* parsed; /* Parsed data structures */
struct hdr_field* next; /* Next header field in the list */
};
</programlisting>
</para>
<para>
<emphasis>Field Description:</emphasis>
<itemizedlist>
<listitem>
<para>
<structfield>type</structfield> - Type of the header field,
the following header field types are defined (and
recognized by the parser):
</para>
<para>
HDR_VIA1, HDR_VIA2, HDR_TO, HDR_FROM, HDR_CSEQ, HDR_CALLID,
HDR_CONTACT, HDR_MAXFORWARDS, HDR_ROUTE, HDR_RECORDROUTE,
HDR_CONTENTTYPE, HDR_CONTENTLENGTH, HDR_AUTHORIZATION,
HDR_EXPIRES, HDR_PROXYAUTH, HDR_WWWAUTH, HDR_SUPPORTED,
HDR_REQUIRE, HDR_PROXYREQUIRE, HDR_UNSUPPORTED, HDR_ALLOW,
HDR_EVENT, HDR_OTHER.
</para>
<para>
Their meaning is self explanatory. HDR_OTHER marks header
field not recognized by the parser.
</para>
</listitem>
<listitem>
<para>
<structfield>name</structfield> - Name of the header field
(the part before colon)
</para>
</listitem>
<listitem>
<para>
<structfield>body</structfield> - body of the header field
(the part after colon)
</para>
</listitem>
<listitem>
<para>
<structfield>parsed</structfield> - Each header field body
can be further parsed. The field contains pointer to parsed
structure if the header field was parsed already. The
pointer is of type <type>void*</type> because it can point
to different types of structure depending on the header
field type.
</para>
</listitem>
<listitem>
<para>
<structfield>next</structfield> - Pointer to the next
header field in linked list.
</para>
</listitem>
</itemizedlist>
</para>
</section>
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