162 lines
5.3 KiB
Groff
162 lines
5.3 KiB
Groff
.\"
|
|
.\" 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_NOOP" "3" "Jun 30, 2000" "BIND9" ""
|
|
.SH NAME
|
|
lwres_nooprequest_render, lwres_noopresponse_render, lwres_nooprequest_parse, lwres_noopresponse_parse, lwres_noopresponse_free, lwres_nooprequest_free \- lightweight resolver no-op message handling
|
|
.SH SYNOPSIS
|
|
\fB#include <lwres/lwres.h>
|
|
.sp
|
|
.na
|
|
lwres_result_t
|
|
lwres_nooprequest_render(lwres_context_t *ctx, lwres_nooprequest_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);
|
|
.ad
|
|
.sp
|
|
.na
|
|
lwres_result_t
|
|
lwres_noopresponse_render(lwres_context_t *ctx, lwres_noopresponse_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);
|
|
.ad
|
|
.sp
|
|
.na
|
|
lwres_result_t
|
|
lwres_nooprequest_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_nooprequest_t **structp);
|
|
.ad
|
|
.sp
|
|
.na
|
|
lwres_result_t
|
|
lwres_noopresponse_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_noopresponse_t **structp);
|
|
.ad
|
|
.sp
|
|
.na
|
|
void
|
|
lwres_noopresponse_free(lwres_context_t *ctx, lwres_noopresponse_t **structp);
|
|
.ad
|
|
.sp
|
|
.na
|
|
void
|
|
lwres_nooprequest_free(lwres_context_t *ctx, lwres_nooprequest_t **structp);
|
|
.ad
|
|
\fR
|
|
.SH "DESCRIPTION"
|
|
.PP
|
|
These are low-level routines for creating and parsing
|
|
lightweight resolver no-op request and response messages.
|
|
.PP
|
|
The no-op message is analogous to a \fBping\fR packet:
|
|
a packet is sent to the resolver daemon and is simply echoed back.
|
|
The opcode is intended to allow a client to determine if the server is
|
|
operational or not.
|
|
.PP
|
|
There are four main functions for the no-op opcode.
|
|
One render function converts a no-op request structure \(em
|
|
\fBlwres_nooprequest_t\fR \(em
|
|
to the lighweight resolver's canonical format.
|
|
It is complemented by a parse function that converts a packet in this
|
|
canonical format to a no-op request structure.
|
|
Another render function converts the no-op response structure \(em
|
|
\fBlwres_noopresponse_t\fR
|
|
to the canonical format.
|
|
This is complemented by a parse function which converts a packet in
|
|
canonical format to a no-op response structure.
|
|
.PP
|
|
These structures are defined in
|
|
\fIlwres/lwres.h\fR.
|
|
They are shown below.
|
|
.sp
|
|
.nf
|
|
#define LWRES_OPCODE_NOOP 0x00000000U
|
|
|
|
typedef struct {
|
|
lwres_uint16_t datalength;
|
|
unsigned char *data;
|
|
} lwres_nooprequest_t;
|
|
|
|
typedef struct {
|
|
lwres_uint16_t datalength;
|
|
unsigned char *data;
|
|
} lwres_noopresponse_t;
|
|
.sp
|
|
.fi
|
|
Although the structures have different types, they are identical.
|
|
This is because the no-op opcode simply echos whatever data was sent:
|
|
the response is therefore identical to the request.
|
|
.PP
|
|
\fBlwres_nooprequest_render()\fR uses resolver
|
|
context \fIctx\fR to convert no-op 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_noopresponse_render()\fR
|
|
performs the same task, except it converts a no-op response structure
|
|
\fBlwres_noopresponse_t\fR to the lightweight resolver's
|
|
canonical format.
|
|
.PP
|
|
\fBlwres_nooprequest_parse()\fR uses context
|
|
\fIctx\fR to convert the contents of packet
|
|
\fIpkt\fR to a \fBlwres_nooprequest_t\fR
|
|
structure. Buffer \fIb\fR provides space to be used
|
|
for storing this structure. When the function succeeds, the resulting
|
|
\fBlwres_nooprequest_t\fR is made available through
|
|
\fI*structp\fR.
|
|
\fBlwres_noopresponse_parse()\fR offers the same
|
|
semantics as \fBlwres_nooprequest_parse()\fR except it
|
|
yields a \fBlwres_noopresponse_t\fR structure.
|
|
.PP
|
|
\fBlwres_noopresponse_free()\fR and
|
|
\fBlwres_nooprequest_free()\fR release the memory in
|
|
resolver context \fIctx\fR that was allocated to the
|
|
\fBlwres_noopresponse_t\fR or \fBlwres_nooprequest_t\fR
|
|
structures referenced via \fIstructp\fR.
|
|
.SH "RETURN VALUES"
|
|
.PP
|
|
The no-op opcode functions
|
|
\fBlwres_nooprequest_render()\fR,
|
|
\fBlwres_noopresponse_render()\fR
|
|
\fBlwres_nooprequest_parse()\fR
|
|
and
|
|
\fBlwres_noopresponse_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
|
|
\fIb\fR
|
|
is too small to accommodate the packet header or the
|
|
\fBlwres_nooprequest_t\fR
|
|
and
|
|
\fBlwres_noopresponse_t\fR
|
|
structures.
|
|
\fBlwres_nooprequest_parse()\fR
|
|
and
|
|
\fBlwres_noopresponse_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
|
|
pktflags
|
|
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)
|