.\" Copyright (C) 2000, 2001, 2004, 2005, 2007, 2014-2016, 2018-2020 Internet Systems Consortium, Inc. ("ISC")

.\" 

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'\" t

.\"     Title: lwres_gabn

.\"    Author: 

.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>

.\"      Date: 2007-06-18

.\"    Manual: BIND9

.\"    Source: ISC

.\"  Language: English

.\"

.TH "LWRES_GABN" "3" "2007\-06\-18" "ISC" "BIND9"

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.SH "NAME"

lwres_gabnrequest_render, lwres_gabnresponse_render, lwres_gabnrequest_parse, lwres_gabnresponse_parse, lwres_gabnresponse_free, lwres_gabnrequest_free \- lightweight resolver getaddrbyname message handling

.SH "SYNOPSIS"

.sp

.ft B

.nf

#include <lwres/lwres\&.h>

.fi

.ft

.HP \w'lwres_result_t\ lwres_gabnrequest_render('u

.BI "lwres_result_t lwres_gabnrequest_render(lwres_context_t\ *" "ctx" ", lwres_gabnrequest_t\ *" "req" ", lwres_lwpacket_t\ *" "pkt" ", lwres_buffer_t\ *" "b" ");"

.HP \w'lwres_result_t\ lwres_gabnresponse_render('u

.BI "lwres_result_t lwres_gabnresponse_render(lwres_context_t\ *" "ctx" ", lwres_gabnresponse_t\ *" "req" ", lwres_lwpacket_t\ *" "pkt" ", lwres_buffer_t\ *" "b" ");"

.HP \w'lwres_result_t\ lwres_gabnrequest_parse('u

.BI "lwres_result_t lwres_gabnrequest_parse(lwres_context_t\ *" "ctx" ", lwres_buffer_t\ *" "b" ", lwres_lwpacket_t\ *" "pkt" ", lwres_gabnrequest_t\ **" "structp" ");"

.HP \w'lwres_result_t\ lwres_gabnresponse_parse('u

.BI "lwres_result_t lwres_gabnresponse_parse(lwres_context_t\ *" "ctx" ", lwres_buffer_t\ *" "b" ", lwres_lwpacket_t\ *" "pkt" ", lwres_gabnresponse_t\ **" "structp" ");"

.HP \w'void\ lwres_gabnresponse_free('u

.BI "void lwres_gabnresponse_free(lwres_context_t\ *" "ctx" ", lwres_gabnresponse_t\ **" "structp" ");"

.HP \w'void\ lwres_gabnrequest_free('u

.BI "void lwres_gabnrequest_free(lwres_context_t\ *" "ctx" ", lwres_gabnrequest_t\ **" "structp" ");"

.SH "DESCRIPTION"

.PP

These are low\-level routines for creating and parsing lightweight resolver name\-to\-address lookup request and response messages\&.

.PP

There are four main functions for the getaddrbyname opcode\&. One render function converts a getaddrbyname request structure \(em

\fBlwres_gabnrequest_t\fR

\(em to the lightweight resolver\*(Aqs canonical format\&. It is complemented by a parse function that converts a packet in this canonical format to a getaddrbyname request structure\&. Another render function converts the getaddrbyname response structure \(em

\fBlwres_gabnresponse_t\fR

\(em to the canonical format\&. This is complemented by a parse function which converts a packet in canonical format to a getaddrbyname response structure\&.

.PP

These structures are defined in

<lwres/lwres\&.h>\&. They are shown below\&.

.PP

.if n \{\

.RS 4

.\}

.nf

#define LWRES_OPCODE_GETADDRSBYNAME     0x00010001U

.fi

.if n \{\

.RE

.\}

.PP

.if n \{\

.RS 4

.\}

.nf

typedef struct lwres_addr lwres_addr_t;

typedef LWRES_LIST(lwres_addr_t) lwres_addrlist_t;

.fi

.if n \{\

.RE

.\}

.PP

.if n \{\

.RS 4

.\}

.nf

typedef struct {

        uint32_t  flags;

        uint32_t  addrtypes;

        uint16_t  namelen;

        char           *name;

} lwres_gabnrequest_t;

.fi

.if n \{\

.RE

.\}

.PP

.if n \{\

.RS 4

.\}

.nf

typedef struct {

        uint32_t          flags;

        uint16_t          naliases;

        uint16_t          naddrs;

        char                   *realname;

        char                  **aliases;

        uint16_t          realnamelen;

        uint16_t         *aliaslen;

        lwres_addrlist_t        addrs;

        void                   *base;

        size_t                  baselen;

} lwres_gabnresponse_t;

.fi

.if n \{\

.RE

.\}

.PP

\fBlwres_gabnrequest_render()\fR

uses resolver context

\fIctx\fR

to convert getaddrbyname request structure

\fIreq\fR

to canonical format\&. The packet header structure

\fIpkt\fR

is initialised and transferred to buffer

\fIb\fR\&. The contents of

\fI*req\fR

are then appended to the buffer in canonical format\&.

\fBlwres_gabnresponse_render()\fR

performs the same task, except it converts a getaddrbyname response structure

\fBlwres_gabnresponse_t\fR

to the lightweight resolver\*(Aqs canonical format\&.

.PP

\fBlwres_gabnrequest_parse()\fR

uses context

\fIctx\fR

to convert the contents of packet

\fIpkt\fR

to a

\fBlwres_gabnrequest_t\fR

structure\&. Buffer

\fIb\fR

provides space to be used for storing this structure\&. When the function succeeds, the resulting

\fBlwres_gabnrequest_t\fR

is made available through

\fI*structp\fR\&.

\fBlwres_gabnresponse_parse()\fR

offers the same semantics as

\fBlwres_gabnrequest_parse()\fR

except it yields a

\fBlwres_gabnresponse_t\fR

structure\&.

.PP

\fBlwres_gabnresponse_free()\fR

and

\fBlwres_gabnrequest_free()\fR

release the memory in resolver context

\fIctx\fR

that was allocated to the

\fBlwres_gabnresponse_t\fR

or

\fBlwres_gabnrequest_t\fR

structures referenced via

\fIstructp\fR\&. Any memory associated with ancillary buffers and strings for those structures is also discarded\&.

.SH "RETURN VALUES"

.PP

The getaddrbyname opcode functions

\fBlwres_gabnrequest_render()\fR,

\fBlwres_gabnresponse_render()\fR\fBlwres_gabnrequest_parse()\fR

and

\fBlwres_gabnresponse_parse()\fR

all return

\fBLWRES_R_SUCCESS\fR

on success\&. They return

\fBLWRES_R_NOMEMORY\fR

if memory allocation fails\&.

\fBLWRES_R_UNEXPECTEDEND\fR

is returned if the available space in the buffer

\fIb\fR

is too small to accommodate the packet header or the

\fBlwres_gabnrequest_t\fR

and

\fBlwres_gabnresponse_t\fR

structures\&.

\fBlwres_gabnrequest_parse()\fR

and

\fBlwres_gabnresponse_parse()\fR

will return

\fBLWRES_R_UNEXPECTEDEND\fR

if the buffer is not empty after decoding the received packet\&. These functions will return

\fBLWRES_R_FAILURE\fR

if

\fIpktflags\fR

in the packet header structure

\fBlwres_lwpacket_t\fR

indicate that the packet is not a response to an earlier query\&.

.SH "SEE ALSO"

.PP

\fBlwres_packet\fR(3)

.SH "AUTHOR"

.PP

\fBInternet Systems Consortium, Inc\&.\fR

.SH "COPYRIGHT"

.br

Copyright \(co 2000, 2001, 2004, 2005, 2007, 2014-2016, 2018-2020 Internet Systems Consortium, Inc. ("ISC")

.br