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diff --git a/lib/liblwres/man/lwres_resutil.docbook b/lib/liblwres/man/lwres_resutil.docbook new file mode 100644 index 000000000..72d6dc614 --- /dev/null +++ b/lib/liblwres/man/lwres_resutil.docbook @@ -0,0 +1,221 @@ +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN"> +<!-- + - Copyright (C) 2001 Internet Software Consortium. + - + - Permission to use, copy, modify, and distribute this software for any + - purpose with or without fee is hereby granted, provided that the above + - copyright notice and this permission notice appear in all copies. + - + - THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM + - DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL + - IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL + - INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, + - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING + - FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, + - NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION + - WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +--> + +<!-- $Id: lwres_resutil.docbook,v 1.1 2004/03/15 20:35:25 as Exp $ --> + +<refentry> + +<refentryinfo> +<date>Jun 30, 2000</date> +</refentryinfo> + +<refmeta> + <refentrytitle>lwres_resutil</refentrytitle> + <manvolnum>3</manvolnum> + <refmiscinfo>BIND9</refmiscinfo> +</refmeta> + +<refnamediv> +<refname>lwres_string_parse</refname> +<refname>lwres_addr_parse</refname> +<refname>lwres_getaddrsbyname</refname> +<refname>lwres_getnamebyaddr</refname> +<refpurpose>lightweight resolver utility functions</refpurpose> +</refnamediv> +<refsynopsisdiv> +<funcsynopsis> +<funcsynopsisinfo>#include <lwres/lwres.h></funcsynopsisinfo> +<funcprototype> +<funcdef> +lwres_result_t +<function>lwres_string_parse</function></funcdef> +<paramdef>lwres_buffer_t *b</paramdef> +<paramdef>char **c</paramdef> +<paramdef>lwres_uint16_t *len</paramdef> +</funcprototype> +<funcprototype> +<funcdef> +lwres_result_t +<function>lwres_addr_parse</function></funcdef> +<paramdef>lwres_buffer_t *b</paramdef> +<paramdef>lwres_addr_t *addr</paramdef> +</funcprototype> +<funcprototype> +<funcdef> +lwres_result_t +<function>lwres_getaddrsbyname</function></funcdef> +<paramdef>lwres_context_t *ctx</paramdef> +<paramdef>const char *name</paramdef> +<paramdef>lwres_uint32_t addrtypes</paramdef> +<paramdef>lwres_gabnresponse_t **structp</paramdef> +</funcprototype> +<funcprototype> +<funcdef> +lwres_result_t +<function>lwres_getnamebyaddr</function></funcdef> +<paramdef>lwres_context_t *ctx</paramdef> +<paramdef>lwres_uint32_t addrtype</paramdef> +<paramdef>lwres_uint16_t addrlen</paramdef> +<paramdef>const unsigned char *addr</paramdef> +<paramdef>lwres_gnbaresponse_t **structp</paramdef> +</funcprototype> +</funcsynopsis> +</refsynopsisdiv> + +<refsect1> +<title>DESCRIPTION</title> + +<para> +<function>lwres_string_parse()</function> retrieves a DNS-encoded +string starting the current pointer of lightweight resolver buffer +<parameter>b</parameter>: i.e. <constant>b->current</constant>. +When the function returns, the address of the first byte of the +encoded string is returned via <parameter>*c</parameter> and the +length of that string is given by <parameter>*len</parameter>. The +buffer's current pointer is advanced to point at the character +following the string length, the encoded string, and the trailing +<type>NULL</type> character. +</para> + +<para> +<function>lwres_addr_parse()</function> extracts an address from the +buffer <parameter>b</parameter>. The buffer's current pointer +<constant>b->current</constant> is presumed to point at an encoded +address: the address preceded by a 32-bit protocol family identifier +and a 16-bit length field. The encoded address is copied to +<constant>addr->address</constant> and +<constant>addr->length</constant> indicates the size in bytes of +the address that was copied. <constant>b->current</constant> is +advanced to point at the next byte of available data in the buffer +following the encoded address. +</para> + +<para> +<function>lwres_getaddrsbyname()</function> +and +<function>lwres_getnamebyaddr()</function> +use the +<type>lwres_gnbaresponse_t</type> +structure defined below: +<programlisting> +typedef struct { + lwres_uint32_t flags; + lwres_uint16_t naliases; + lwres_uint16_t naddrs; + char *realname; + char **aliases; + lwres_uint16_t realnamelen; + lwres_uint16_t *aliaslen; + lwres_addrlist_t addrs; + void *base; + size_t baselen; +} lwres_gabnresponse_t; +</programlisting> +The contents of this structure are not manipulated directly but +they are controlled through the +<citerefentry> +<refentrytitle>lwres_gabn</refentrytitle><manvolnum>3 +</manvolnum> +</citerefentry> +functions. +</para> + +<para> +The lightweight resolver uses +<function>lwres_getaddrsbyname()</function> to perform foward lookups. +Hostname <parameter>name</parameter> is looked up using the resolver +context <parameter>ctx</parameter> for memory allocation. +<parameter>addrtypes</parameter> is a bitmask indicating which type of +addresses are to be looked up. Current values for this bitmask are +<type>LWRES_ADDRTYPE_V4</type> for IPv4 addresses and +<type>LWRES_ADDRTYPE_V6</type> for IPv6 addresses. Results of the +lookup are returned in <parameter>*structp</parameter>. +</para> + +<para> +<function>lwres_getnamebyaddr()</function> performs reverse lookups. +Resolver context <parameter>ctx</parameter> is used for memory +allocation. The address type is indicated by +<parameter>addrtype</parameter>: <type>LWRES_ADDRTYPE_V4</type> or +<type>LWRES_ADDRTYPE_V6</type>. The address to be looked up is given +by <parameter>addr</parameter> and its length is +<parameter>addrlen</parameter> bytes. The result of the function call +is made available through <parameter>*structp</parameter>. +</para> +</refsect1> + +<refsect1> +<title>RETURN VALUES</title> +<para> +Successful calls to +<function>lwres_string_parse()</function> +and +<function>lwres_addr_parse()</function> +return +<errorcode>LWRES_R_SUCCESS.</errorcode> +Both functions return +<errorcode>LWRES_R_FAILURE</errorcode> +if the buffer is corrupt or +<errorcode>LWRES_R_UNEXPECTEDEND</errorcode> +if the buffer has less space than expected for the components of the +encoded string or address. +</para> +<para> +<function>lwres_getaddrsbyname()</function> +returns +<errorcode>LWRES_R_SUCCESS</errorcode> +on success and it returns +<errorcode>LWRES_R_NOTFOUND</errorcode> +if the hostname +<parameter>name</parameter> +could not be found. +</para> +<para> +<errorcode>LWRES_R_SUCCESS</errorcode> +is returned by a successful call to +<function>lwres_getnamebyaddr()</function>. +</para> + +<para> +Both +<function>lwres_getaddrsbyname()</function> +and +<function>lwres_getnamebyaddr()</function> +return +<errorcode>LWRES_R_NOMEMORY</errorcode> +when memory allocation requests fail and +<errorcode>LWRES_R_UNEXPECTEDEND</errorcode> +if the buffers used for sending queries and receiving replies are too +small. +</para> + +</refsect1> +<refsect1> +<title>SEE ALSO</title> +<para> +<citerefentry> +<refentrytitle>lwres_buffer</refentrytitle><manvolnum>3</manvolnum> +</citerefentry>, + +<citerefentry> +<refentrytitle>lwres_gabn</refentrytitle><manvolnum>3</manvolnum> +</citerefentry>. +</para> + +</refsect1> +</refentry> |