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lwres_gnbaresponse_parse


  1. lwres_gnbaresponse_parse.3.man


1. lwres_gnbaresponse_parse.3.man

Manpage of LWRES_GNBA

LWRES_GNBA

Section: BIND9 (3)
Updated: Jun 30, 2000
Index Return to Main Contents
 

NAME

lwres_gnbarequest_render, lwres_gnbaresponse_render, lwres_gnbarequest_parse, lwres_gnbaresponse_parse, lwres_gnbaresponse_free, lwres_gnbarequest_free - lightweight resolver getnamebyaddress message handling  

SYNOPSIS

#include <lwres/lwres.h>
lwres_result_t lwres_gnbarequest_render(lwres_context_t *ctx, lwres_gnbarequest_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);
lwres_result_t lwres_gnbaresponse_render(lwres_context_t *ctx, lwres_gnbaresponse_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);
lwres_result_t lwres_gnbarequest_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gnbarequest_t **structp);
lwres_result_t lwres_gnbaresponse_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gnbaresponse_t **structp);
void lwres_gnbaresponse_free(lwres_context_t *ctx, lwres_gnbaresponse_t **structp);
void lwres_gnbarequest_free(lwres_context_t *ctx, lwres_gnbarequest_t **structp);
 

DESCRIPTION

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

There are four main functions for the getnamebyaddr opcode. One render function converts a getnamebyaddr request structure --- lwres_gnbarequest_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 getnamebyaddr request structure. Another render function converts the getnamebyaddr response structure --- lwres_gnbaresponse_t to the canonical format. This is complemented by a parse function which converts a packet in canonical format to a getnamebyaddr response structure.

These structures are defined in lwres/lwres.h. They are shown below.

#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;

lwres_gnbarequest_render() 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. lwres_gnbaresponse_render() performs the same task, except it converts a getnamebyaddr response structure lwres_gnbaresponse_t to the lightweight resolver's canonical format.

lwres_gnbarequest_parse() uses context ctx to convert the contents of packet pkt to a lwres_gnbarequest_t structure. Buffer b provides space to be used for storing this structure. When the function succeeds, the resulting lwres_gnbarequest_t is made available through *structp. lwres_gnbaresponse_parse() offers the same semantics as lwres_gnbarequest_parse() except it yields a lwres_gnbaresponse_t structure.

lwres_gnbaresponse_free() and lwres_gnbarequest_free() release the memory in resolver context ctx that was allocated to the lwres_gnbaresponse_t or lwres_gnbarequest_t structures referenced via structp. Any memory associated with ancillary buffers and strings for those structures is also discarded.  

RETURN VALUES

The getnamebyaddr opcode functions lwres_gnbarequest_render(), lwres_gnbaresponse_render() lwres_gnbarequest_parse() and lwres_gnbaresponse_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_gnbarequest_t and lwres_gnbaresponse_t structures. lwres_gnbarequest_parse() and lwres_gnbaresponse_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).  

COPYRIGHT

Copyright © 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
Copyright © 2000, 2001 Internet Software Consortium.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUES
SEE ALSO
COPYRIGHT

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Time: 17:31:34 GMT, October 23, 2013

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