188 lines
5.3 KiB
Groff
188 lines
5.3 KiB
Groff
.\"
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.\" Copyright (C) 2000, 2001 Internet Software Consortium.
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.\"
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.\" Permission to use, copy, modify, and distribute this software for any
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.\" purpose with or without fee is hereby granted, provided that the above
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.\" copyright notice and this permission notice appear in all copies.
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.\"
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.\" THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
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.\" DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
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.\" INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
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.\" INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
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.\" FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
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.\" NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
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.\" WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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.\"
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.TH "LWRES_GNBA" "3" "Jun 30, 2000" "BIND9" ""
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.SH NAME
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lwres_gnbarequest_render, lwres_gnbaresponse_render, lwres_gnbarequest_parse, lwres_gnbaresponse_parse, lwres_gnbaresponse_free, lwres_gnbarequest_free \- lightweight resolver getnamebyaddress message handling
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.SH SYNOPSIS
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\fB#include <lwres/lwres.h>
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.sp
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.na
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lwres_result_t
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lwres_gnbarequest_render(lwres_context_t *\fIctx\fB, lwres_gnbarequest_t *\fIreq\fB, lwres_lwpacket_t *\fIpkt\fB, lwres_buffer_t *\fIb\fB);
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.ad
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.sp
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.na
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lwres_result_t
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lwres_gnbaresponse_render(lwres_context_t *ctx, lwres_gnbaresponse_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);
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.ad
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.sp
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.na
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lwres_result_t
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lwres_gnbarequest_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gnbarequest_t **structp);
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.ad
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.sp
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.na
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lwres_result_t
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lwres_gnbaresponse_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gnbaresponse_t **structp);
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.ad
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.sp
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.na
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void
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lwres_gnbaresponse_free(lwres_context_t *ctx, lwres_gnbaresponse_t **structp);
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.ad
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.sp
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.na
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void
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lwres_gnbarequest_free(lwres_context_t *ctx, lwres_gnbarequest_t **structp);
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.ad
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\fR
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.SH "DESCRIPTION"
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.PP
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These are low-level routines for creating and parsing
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lightweight resolver address-to-name lookup request and
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response messages.
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.PP
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There are four main functions for the getnamebyaddr opcode.
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One render function converts a getnamebyaddr request structure \(em
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\fBlwres_gnbarequest_t\fR \(em
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to the lightweight resolver's canonical format.
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It is complemented by a parse function that converts a packet in this
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canonical format to a getnamebyaddr request structure.
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Another render function converts the getnamebyaddr response structure \(em
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\fBlwres_gnbaresponse_t\fR
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to the canonical format.
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This is complemented by a parse function which converts a packet in
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canonical format to a getnamebyaddr response structure.
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.PP
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These structures are defined in
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\fIlwres/lwres.h\fR.
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They are shown below.
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.sp
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.nf
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#define LWRES_OPCODE_GETNAMEBYADDR 0x00010002U
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typedef struct {
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lwres_uint32_t flags;
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lwres_addr_t addr;
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} lwres_gnbarequest_t;
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typedef struct {
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lwres_uint32_t flags;
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lwres_uint16_t naliases;
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char *realname;
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char **aliases;
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lwres_uint16_t realnamelen;
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lwres_uint16_t *aliaslen;
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void *base;
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size_t baselen;
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} lwres_gnbaresponse_t;
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.sp
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.fi
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.PP
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\fBlwres_gnbarequest_render()\fR
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uses resolver context
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ctx
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to convert getnamebyaddr request structure
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req
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to canonical format.
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The packet header structure
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pkt
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is initialised and transferred to
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buffer
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b.
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The contents of
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*req
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are then appended to the buffer in canonical format.
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\fBlwres_gnbaresponse_render()\fR
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performs the same task, except it converts a getnamebyaddr response structure
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\fBlwres_gnbaresponse_t\fR
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to the lightweight resolver's canonical format.
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.PP
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\fBlwres_gnbarequest_parse()\fR
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uses context
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ctx
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to convert the contents of packet
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pkt
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to a
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\fBlwres_gnbarequest_t\fR
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structure.
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Buffer
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b
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provides space to be used for storing this structure.
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When the function succeeds, the resulting
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\fBlwres_gnbarequest_t\fR
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is made available through
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*structp.
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\fBlwres_gnbaresponse_parse()\fR
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offers the same semantics as
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\fBlwres_gnbarequest_parse()\fR
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except it yields a
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\fBlwres_gnbaresponse_t\fR
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structure.
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.PP
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\fBlwres_gnbaresponse_free()\fR
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and
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\fBlwres_gnbarequest_free()\fR
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release the memory in resolver context
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ctx
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that was allocated to the
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\fBlwres_gnbaresponse_t\fR
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or
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\fBlwres_gnbarequest_t\fR
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structures referenced via
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structp.
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Any memory associated with ancillary buffers and strings for those
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structures is also discarded.
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.SH "RETURN VALUES"
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.PP
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The getnamebyaddr opcode functions
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\fBlwres_gnbarequest_render()\fR,
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\fBlwres_gnbaresponse_render()\fR
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\fBlwres_gnbarequest_parse()\fR
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and
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\fBlwres_gnbaresponse_parse()\fR
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all return
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LWRES_R_SUCCESS
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on success.
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They return
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LWRES_R_NOMEMORY
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if memory allocation fails.
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LWRES_R_UNEXPECTEDEND
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is returned if the available space in the buffer
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b
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is too small to accommodate the packet header or the
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\fBlwres_gnbarequest_t\fR
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and
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\fBlwres_gnbaresponse_t\fR
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structures.
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\fBlwres_gnbarequest_parse()\fR
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and
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\fBlwres_gnbaresponse_parse()\fR
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will return
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LWRES_R_UNEXPECTEDEND
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if the buffer is not empty after decoding the received packet.
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These functions will return
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LWRES_R_FAILURE
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if
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\fBpktflags\fR
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in the packet header structure
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\fBlwres_lwpacket_t\fR
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indicate that the packet is not a response to an earlier query.
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.SH "SEE ALSO"
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.PP
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\fBlwres_packet\fR(3).
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