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.\"
.\" Copyright (C) 2000, 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.
.\"
.TH "LWRES_GNBA" "3" "Jun 30, 2000" "BIND9" ""
.SH NAME
lwres_gnbarequest_render, lwres_gnbaresponse_render, lwres_gnbarequest_parse, lwres_gnbaresponse_parse, lwres_gnbaresponse_free, lwres_gnbarequest_free \- lightweight resolver getnamebyaddress message handling
.SH SYNOPSIS
\fB#include <lwres/lwres.h>
.sp
.na
lwres_result_t
lwres_gnbarequest_render(lwres_context_t *\fIctx\fB, lwres_gnbarequest_t *\fIreq\fB, lwres_lwpacket_t *\fIpkt\fB, lwres_buffer_t *\fIb\fB);
.ad
.sp
.na
lwres_result_t
lwres_gnbaresponse_render(lwres_context_t *ctx, lwres_gnbaresponse_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);
.ad
.sp
.na
lwres_result_t
lwres_gnbarequest_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gnbarequest_t **structp);
.ad
.sp
.na
lwres_result_t
lwres_gnbaresponse_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gnbaresponse_t **structp);
.ad
.sp
.na
void
lwres_gnbaresponse_free(lwres_context_t *ctx, lwres_gnbaresponse_t **structp);
.ad
.sp
.na
void
lwres_gnbarequest_free(lwres_context_t *ctx, lwres_gnbarequest_t **structp);
.ad
\fR.SH "DESCRIPTION"
.PP
These are low-level routines for creating and parsing
lightweight resolver address-to-name lookup request and
response messages.
.PP
There are four main functions for the getnamebyaddr opcode.
One render function converts a getnamebyaddr request structure \(em
\fBlwres_gnbarequest_t\fR \(em
to the lightweight resolver's canonical format.
It is complemented by a parse function that converts a packet in this
canonical format to a getnamebyaddr request structure.
Another render function converts the getnamebyaddr response structure \(em
\fBlwres_gnbaresponse_t\fR
to the canonical format.
This is complemented by a parse function which converts a packet in
canonical format to a getnamebyaddr response structure.
.PP
These structures are defined in
\fIlwres/lwres.h\fR.
They are shown below.
.sp
.nf
#define LWRES_OPCODE_GETNAMEBYADDR 0x00010002U
typedef struct {
lwres_uint32_t flags;
lwres_addr_t addr;
} lwres_gnbarequest_t;
typedef struct {
lwres_uint32_t flags;
lwres_uint16_t naliases;
char *realname;
char **aliases;
lwres_uint16_t realnamelen;
lwres_uint16_t *aliaslen;
void *base;
size_t baselen;
} lwres_gnbaresponse_t;
.sp
.fi
.PP
\fBlwres_gnbarequest_render()\fR
uses resolver context
ctx
to convert getnamebyaddr request structure
req
to canonical format.
The packet header structure
pkt
is initialised and transferred to
buffer
b.
The contents of
*req
are then appended to the buffer in canonical format.
\fBlwres_gnbaresponse_render()\fR
performs the same task, except it converts a getnamebyaddr response structure
\fBlwres_gnbaresponse_t\fR
to the lightweight resolver's canonical format.
.PP
\fBlwres_gnbarequest_parse()\fR
uses context
ctx
to convert the contents of packet
pkt
to a
\fBlwres_gnbarequest_t\fR
structure.
Buffer
b
provides space to be used for storing this structure.
When the function succeeds, the resulting
\fBlwres_gnbarequest_t\fR
is made available through
*structp.
\fBlwres_gnbaresponse_parse()\fR
offers the same semantics as
\fBlwres_gnbarequest_parse()\fR
except it yields a
\fBlwres_gnbaresponse_t\fR
structure.
.PP
\fBlwres_gnbaresponse_free()\fR
and
\fBlwres_gnbarequest_free()\fR
release the memory in resolver context
ctx
that was allocated to the
\fBlwres_gnbaresponse_t\fR
or
\fBlwres_gnbarequest_t\fR
structures referenced via
structp.
Any memory associated with ancillary buffers and strings for those
structures is also discarded.
.SH "RETURN VALUES"
.PP
The getnamebyaddr opcode functions
\fBlwres_gnbarequest_render()\fR,
\fBlwres_gnbaresponse_render()\fR
\fBlwres_gnbarequest_parse()\fR
and
\fBlwres_gnbaresponse_parse()\fR
all return
LWRES_R_SUCCESS
on success.
They return
LWRES_R_NOMEMORY
if memory allocation fails.
LWRES_R_UNEXPECTEDEND
is returned if the available space in the buffer
b
is too small to accommodate the packet header or the
\fBlwres_gnbarequest_t\fR
and
\fBlwres_gnbaresponse_t\fR
structures.
\fBlwres_gnbarequest_parse()\fR
and
\fBlwres_gnbaresponse_parse()\fR
will return
LWRES_R_UNEXPECTEDEND
if the buffer is not empty after decoding the received packet.
These functions will return
LWRES_R_FAILURE
if
\fBpktflags\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).
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