On Apache
Under GNU General Public License
2024-04-19 12:18 @18.118.145.114 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
LWRES_NOOP(3) BIND9 LWRES_NOOP(3)
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
SYNOPSIS
#include <lwres/lwres.h>
lwres_result_t lwres_nooprequest_render(lwres_context_t *ctx, lwres_nooprequest_t *req,
lwres_lwpacket_t *pkt, lwres_buffer_t *b);
lwres_result_t lwres_noopresponse_render(lwres_context_t *ctx, lwres_noopresponse_t *req,
lwres_lwpacket_t *pkt, lwres_buffer_t *b);
lwres_result_t lwres_nooprequest_parse(lwres_context_t *ctx, lwres_buffer_t *b,
lwres_lwpacket_t *pkt,
lwres_nooprequest_t **structp);
lwres_result_t lwres_noopresponse_parse(lwres_context_t *ctx, lwres_buffer_t *b,
lwres_lwpacket_t *pkt,
lwres_noopresponse_t **structp);
void lwres_noopresponse_free(lwres_context_t *ctx, lwres_noopresponse_t **structp);
void lwres_nooprequest_free(lwres_context_t *ctx, lwres_nooprequest_t **structp);
DESCRIPTION
These are low-level routines for creating and parsing lightweight resolver no-op request
and response messages.
The no-op message is analogous to a ping 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.
There are four main functions for the no-op opcode. One render function converts a no-op
request structure -- lwres_nooprequest_t -- to the lightweight 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 -- lwres_noopresponse_t to the canonical format. This is complemented by a parse
function which converts a packet in canonical format to a no-op response structure.
These structures are defined in lwres/lwres.h. They are shown below.
#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;
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.
lwres_nooprequest_render() uses resolver context ctx to convert no-op 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.
lwres_noopresponse_render() performs the same task, except it converts a no-op response
structure lwres_noopresponse_t to the lightweight resolver's canonical format.
lwres_nooprequest_parse() uses context ctx to convert the contents of packet pkt to a
lwres_nooprequest_t structure. Buffer b provides space to be used for storing this
structure. When the function succeeds, the resulting lwres_nooprequest_t is made available
through *structp. lwres_noopresponse_parse() offers the same semantics as
lwres_nooprequest_parse() except it yields a lwres_noopresponse_t structure.
lwres_noopresponse_free() and lwres_nooprequest_free() release the memory in resolver
context ctx that was allocated to the lwres_noopresponse_t or lwres_nooprequest_t
structures referenced via structp.
RETURN VALUES
The no-op opcode functions lwres_nooprequest_render(),
lwres_noopresponse_render()lwres_nooprequest_parse() and lwres_noopresponse_parse() 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 lwres_nooprequest_t and lwres_noopresponse_t
structures. lwres_nooprequest_parse() and lwres_noopresponse_parse() 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
lwres_lwpacket_t indicate that the packet is not a response to an earlier query.
SEE ALSO
lwres_packet(3)
AUTHOR
Internet Systems Consortium, Inc.
COPYRIGHT
Copyright (C) 2000, 2001, 2004, 2005, 2007, 2014-2016, 2018 Internet Systems Consortium,
Inc. ("ISC")
ISC 2007-06-18 LWRES_NOOP(3)
Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2024-04-19 12:18 @18.118.145.114 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)