contrib/bind-9.2.4rc7/lib/dns/soa.c

   1 /*
   2  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000, 2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: soa.c,v 1.3.2.1 2004/03/09 06:11:08 marka Exp $ */
  19
  20 #include <config.h>
  21
  22 #include <isc/util.h>
  23
  24 #include <dns/rdata.h>
  25 #include <dns/soa.h>
  26
  27 static inline isc_uint32_t
  28 decode_uint32(unsigned char *p) {
  29         return ((p[0] << 24) +
  30                 (p[1] << 16) +
  31                 (p[2] <<  8) +
  32                 (p[3] <<  0));
  33 }
  34
  35 static inline void
  36 encode_uint32(isc_uint32_t val, unsigned char *p) {
  37         p[0] = (isc_uint8_t)(val >> 24);
  38         p[1] = (isc_uint8_t)(val >> 16);
  39         p[2] = (isc_uint8_t)(val >>  8);
  40         p[3] = (isc_uint8_t)(val >>  0);
  41 }
  42
  43 static isc_uint32_t
  44 soa_get(dns_rdata_t *rdata, int offset) {
  45         INSIST(rdata->type == dns_rdatatype_soa);
  46         /*
  47          * Locate the field within the SOA RDATA based
  48          * on its position relative to the end of the data.
  49          *
  50          * This is a bit of a kludge, but the alternative approach of
  51          * using dns_rdata_tostruct() and dns_rdata_fromstruct() would
  52          * involve a lot of unnecessary work (like building domain
  53          * names and allocating temporary memory) when all we really
  54          * want to do is to get 32 bits of fixed-sized data.
  55          */
  56         INSIST(rdata->length >= 20);
  57         INSIST(offset >= 0 && offset <= 16);
  58         return (decode_uint32(rdata->data + rdata->length - 20 + offset));
  59 }
  60
  61 isc_uint32_t
  62 dns_soa_getserial(dns_rdata_t *rdata) {
  63         return soa_get(rdata, 0);
  64 }
  65 isc_uint32_t
  66 dns_soa_getrefresh(dns_rdata_t *rdata) {
  67         return soa_get(rdata, 4);
  68 }
  69 isc_uint32_t
  70 dns_soa_getretry(dns_rdata_t *rdata) {
  71         return soa_get(rdata, 8);
  72 }
  73 isc_uint32_t
  74 dns_soa_getexpire(dns_rdata_t *rdata) {
  75         return soa_get(rdata, 12);
  76 }
  77 isc_uint32_t
  78 dns_soa_getminimum(dns_rdata_t *rdata) {
  79         return soa_get(rdata, 16);
  80 }
  81
  82 static void
  83 soa_set(dns_rdata_t *rdata, isc_uint32_t val, int offset) {
  84         INSIST(rdata->type == dns_rdatatype_soa);
  85         INSIST(rdata->length >= 20);
  86         INSIST(offset >= 0 && offset <= 16);
  87         encode_uint32(val, rdata->data + rdata->length - 20 + offset);
  88 }
  89
  90 void
  91 dns_soa_setserial(isc_uint32_t val, dns_rdata_t *rdata) {
  92         soa_set(rdata, val, 0);
  93 }
  94 void
  95 dns_soa_setrefresh(isc_uint32_t val, dns_rdata_t *rdata) {
  96         soa_set(rdata, val, 4);
  97 }
  98 void
  99 dns_soa_setretry(isc_uint32_t val, dns_rdata_t *rdata) {
 100         soa_set(rdata, val, 8);
 101 }
 102 void
 103 dns_soa_setexpire(isc_uint32_t val, dns_rdata_t *rdata) {
 104         soa_set(rdata, val, 12);
 105 }
 106 void
 107 dns_soa_setminimum(isc_uint32_t val, dns_rdata_t *rdata) {
 108         soa_set(rdata, val, 16);
 109 }