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Title: lwres_gnba
Author:
Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
Date: 2007-06-18
Manual: BIND9
Source: ISC
Language: English
* Define some portability stuff
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http://bugs.debian.org/507673
http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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* set default formatting
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* MAIN CONTENT STARTS HERE *
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#include <lwres/lwres.h>
\w'lwres_result_t lwres_gnbarequest_render('u "lwres_result_t lwres_gnbarequest_render(lwres_context_t *" "ctx" ", lwres_gnbarequest_t *" "req" ", lwres_lwpacket_t *" "pkt" ", lwres_buffer_t *" "b" ");"
\w'lwres_result_t lwres_gnbaresponse_render('u "lwres_result_t lwres_gnbaresponse_render(lwres_context_t *" "ctx" ", lwres_gnbaresponse_t *" "req" ", lwres_lwpacket_t *" "pkt" ", lwres_buffer_t *" "b" ");"
\w'lwres_result_t lwres_gnbarequest_parse('u "lwres_result_t lwres_gnbarequest_parse(lwres_context_t *" "ctx" ", lwres_buffer_t *" "b" ", lwres_lwpacket_t *" "pkt" ", lwres_gnbarequest_t **" "structp" ");"
\w'lwres_result_t lwres_gnbaresponse_parse('u "lwres_result_t lwres_gnbaresponse_parse(lwres_context_t *" "ctx" ", lwres_buffer_t *" "b" ", lwres_lwpacket_t *" "pkt" ", lwres_gnbaresponse_t **" "structp" ");"
\w'void lwres_gnbaresponse_free('u "void lwres_gnbaresponse_free(lwres_context_t *" "ctx" ", lwres_gnbaresponse_t **" "structp" ");"
\w'void lwres_gnbarequest_free('u "void lwres_gnbarequest_free(lwres_context_t *" "ctx" ", lwres_gnbarequest_t **" "structp" ");"
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 \(em lwres_gnbarequest_t \(em to the lightweight resolver\*(Aqs 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 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\*(Aqs 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.
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.
lwres_packet(3).
Internet Systems Consortium, Inc.
Copyright \(co 2000, 2001, 2004, 2005, 2007, 2014-2016 Internet Systems Consortium, Inc. ("ISC")