lwres_gnba(3)

LWRES_GNBA(3)                 BIND9                 LWRES_GNBA(3)

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_result_t
                                              lwres_gnbaresponse_render(lwres_context_t *ctx,
                                              lwres_gnbaresponse_t *req,
                                              lwres_lwpacket_t *pkt

     lwres_result_t lwres_gnbarequest_parse(lwres_context_t *ctx,
                                            lwres_buffer_t *b,
                                            lwres_lwpacket_t *pkt

     lwres_result_t
                                             lwres_gnbaresponse_parse(lwres_context_t *ctx,
                                             lwres_buffer_t *b,
                                             lwres_lwpacket_t *pkt

     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.

ISC                  Last change: 2007-06-18                    1

LWRES_GNBA(3)                 BIND9                 LWRES_GNBA(3)

         #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

ISC                  Last change: 2007-06-18                    2

LWRES_GNBA(3)                 BIND9                 LWRES_GNBA(3)

     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).

AUTHOR

     Internet Systems Consortium, Inc.

COPYRIGHT

     Copyright 8c9 2004, 2005, 2007, 2014-2016 Internet Systems
     Consortium, Inc. ("ISC")
     Copyright 8c9 2000, 2001 Internet Software Consortium.

ISC                  Last change: 2007-06-18                    3