contrib/bind-9.2.4rc7/lib/lwres/man/lwres_gabn.3

   1 .\" Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
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  16 .\" $Id: lwres_gabn.3,v 1.13.2.2 2004/03/15 04:45:01 marka Exp $
  17 .\"
  18 .TH "LWRES_GABN" "3" "Jun 30, 2000" "BIND9" ""
  19 .SH NAME
  20 lwres_gabnrequest_render, lwres_gabnresponse_render, lwres_gabnrequest_parse, lwres_gabnresponse_parse, lwres_gabnresponse_free, lwres_gabnrequest_free \- lightweight resolver getaddrbyname message handling
  21 .SH SYNOPSIS
  22 \fB#include <lwres/lwres.h>
  23 .sp
  24 .na
  25 lwres_result_t
  26 lwres_gabnrequest_render(lwres_context_t *ctx, lwres_gabnrequest_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);
  27 .ad
  28 .sp
  29 .na
  30 lwres_result_t
  31 lwres_gabnresponse_render(lwres_context_t *ctx, lwres_gabnresponse_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);
  32 .ad
  33 .sp
  34 .na
  35 lwres_result_t
  36 lwres_gabnrequest_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gabnrequest_t **structp);
  37 .ad
  38 .sp
  39 .na
  40 lwres_result_t
  41 lwres_gabnresponse_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gabnresponse_t **structp);
  42 .ad
  43 .sp
  44 .na
  45 void
  46 lwres_gabnresponse_free(lwres_context_t *ctx, lwres_gabnresponse_t **structp);
  47 .ad
  48 .sp
  49 .na
  50 void
  51 lwres_gabnrequest_free(lwres_context_t *ctx, lwres_gabnrequest_t **structp);
  52 .ad
  53 \fR
  54 .SH "DESCRIPTION"
  55 .PP
  56 These are low-level routines for creating and parsing
  57 lightweight resolver name-to-address lookup request and
  58 response messages.
  59 .PP
  60 There are four main functions for the getaddrbyname opcode.
  61 One render function converts a getaddrbyname request structure \(em
  62 \fBlwres_gabnrequest_t\fR \(em
  63 to the lighweight resolver's canonical format.
  64 It is complemented by a parse function that converts a packet in this
  65 canonical format to a getaddrbyname request structure.
  66 Another render function converts the getaddrbyname response structure \(em
  67 \fBlwres_gabnresponse_t\fR \(em
  68 to the canonical format.
  69 This is complemented by a parse function which converts a packet in
  70 canonical format to a getaddrbyname response structure.
  71 .PP
  72 These structures are defined in
  73 \fI<lwres/lwres.h>\fR.
  74 They are shown below.
  75 .sp
  76 .nf
  77 #define LWRES_OPCODE_GETADDRSBYNAME     0x00010001U
  78
  79 typedef struct lwres_addr lwres_addr_t;
  80 typedef LWRES_LIST(lwres_addr_t) lwres_addrlist_t;
  81
  82 typedef struct {
  83         lwres_uint32_t  flags;
  84         lwres_uint32_t  addrtypes;
  85         lwres_uint16_t  namelen;
  86         char           *name;
  87 } lwres_gabnrequest_t;
  88
  89 typedef struct {
  90         lwres_uint32_t          flags;
  91         lwres_uint16_t          naliases;
  92         lwres_uint16_t          naddrs;
  93         char                   *realname;
  94         char                  **aliases;
  95         lwres_uint16_t          realnamelen;
  96         lwres_uint16_t         *aliaslen;
  97         lwres_addrlist_t        addrs;
  98         void                   *base;
  99         size_t                  baselen;
 100 } lwres_gabnresponse_t;
 101 .sp
 102 .fi
 103 .PP
 104 \fBlwres_gabnrequest_render()\fR
 105 uses resolver context
 106 \fIctx\fR
 107 to convert getaddrbyname request structure
 108 \fIreq\fR
 109 to canonical format.
 110 The packet header structure
 111 \fIpkt\fR
 112 is initialised and transferred to
 113 buffer
 114 \fIb\fR.
 115 The contents of
 116 \fI*req\fR
 117 are then appended to the buffer in canonical format.
 118 \fBlwres_gabnresponse_render()\fR
 119 performs the same task, except it converts a getaddrbyname response structure
 120 \fBlwres_gabnresponse_t\fR
 121 to the lightweight resolver's canonical format.
 122 .PP
 123 \fBlwres_gabnrequest_parse()\fR
 124 uses context
 125 \fIctx\fR
 126 to convert the contents of packet
 127 \fIpkt\fR
 128 to a
 129 \fBlwres_gabnrequest_t\fR
 130 structure.
 131 Buffer
 132 \fIb\fR
 133 provides space to be used for storing this structure.
 134 When the function succeeds, the resulting
 135 \fBlwres_gabnrequest_t\fR
 136 is made available through
 137 \fI*structp\fR.
 138 \fBlwres_gabnresponse_parse()\fR
 139 offers the same semantics as
 140 \fBlwres_gabnrequest_parse()\fR
 141 except it yields a
 142 \fBlwres_gabnresponse_t\fR
 143 structure.
 144 .PP
 145 \fBlwres_gabnresponse_free()\fR
 146 and
 147 \fBlwres_gabnrequest_free()\fR
 148 release the memory in resolver context
 149 \fIctx\fR
 150 that was allocated to the
 151 \fBlwres_gabnresponse_t\fR
 152 or
 153 \fBlwres_gabnrequest_t\fR
 154 structures referenced via
 155 \fIstructp\fR.
 156 Any memory associated with ancillary buffers and strings for those
 157 structures is also discarded.
 158 .SH "RETURN VALUES"
 159 .PP
 160 The getaddrbyname opcode functions
 161 \fBlwres_gabnrequest_render()\fR,
 162 \fBlwres_gabnresponse_render()\fR
 163 \fBlwres_gabnrequest_parse()\fR
 164 and
 165 \fBlwres_gabnresponse_parse()\fR
 166 all return
 167 LWRES_R_SUCCESS
 168 on success.
 169 They return
 170 LWRES_R_NOMEMORY
 171 if memory allocation fails.
 172 LWRES_R_UNEXPECTEDEND
 173 is returned if the available space in the buffer
 174 \fIb\fR
 175 is too small to accommodate the packet header or the
 176 \fBlwres_gabnrequest_t\fR
 177 and
 178 \fBlwres_gabnresponse_t\fR
 179 structures.
 180 \fBlwres_gabnrequest_parse()\fR
 181 and
 182 \fBlwres_gabnresponse_parse()\fR
 183 will return
 184 LWRES_R_UNEXPECTEDEND
 185 if the buffer is not empty after decoding the received packet.
 186 These functions will return
 187 LWRES_R_FAILURE
 188 if
 189 \fBpktflags\fR
 190 in the packet header structure
 191 \fBlwres_lwpacket_t\fR
 192 indicate that the packet is not a response to an earlier query.
 193 .SH "SEE ALSO"
 194 .PP
 195 \fBlwres_packet\fR(3)