contrib/bind-9.5.2/lib/dns/soa.c

   1 /*
   2  * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000, 2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or 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 1.8 2007/06/19 23:47:16 tbox Exp $ */
  19
  20 /*! \file */
  21
  22 #include <config.h>
  23
  24 #include <isc/util.h>
  25
  26 #include <dns/rdata.h>
  27 #include <dns/soa.h>
  28
  29 static inline isc_uint32_t
  30 decode_uint32(unsigned char *p) {
  31         return ((p[0] << 24) +
  32                 (p[1] << 16) +
  33                 (p[2] <<  8) +
  34                 (p[3] <<  0));
  35 }
  36
  37 static inline void
  38 encode_uint32(isc_uint32_t val, unsigned char *p) {
  39         p[0] = (isc_uint8_t)(val >> 24);
  40         p[1] = (isc_uint8_t)(val >> 16);
  41         p[2] = (isc_uint8_t)(val >>  8);
  42         p[3] = (isc_uint8_t)(val >>  0);
  43 }
  44
  45 static isc_uint32_t
  46 soa_get(dns_rdata_t *rdata, int offset) {
  47         INSIST(rdata->type == dns_rdatatype_soa);
  48         /*
  49          * Locate the field within the SOA RDATA based
  50          * on its position relative to the end of the data.
  51          *
  52          * This is a bit of a kludge, but the alternative approach of
  53          * using dns_rdata_tostruct() and dns_rdata_fromstruct() would
  54          * involve a lot of unnecessary work (like building domain
  55          * names and allocating temporary memory) when all we really
  56          * want to do is to get 32 bits of fixed-sized data.
  57          */
  58         INSIST(rdata->length >= 20);
  59         INSIST(offset >= 0 && offset <= 16);
  60         return (decode_uint32(rdata->data + rdata->length - 20 + offset));
  61 }
  62
  63 isc_uint32_t
  64 dns_soa_getserial(dns_rdata_t *rdata) {
  65         return soa_get(rdata, 0);
  66 }
  67 isc_uint32_t
  68 dns_soa_getrefresh(dns_rdata_t *rdata) {
  69         return soa_get(rdata, 4);
  70 }
  71 isc_uint32_t
  72 dns_soa_getretry(dns_rdata_t *rdata) {
  73         return soa_get(rdata, 8);
  74 }
  75 isc_uint32_t
  76 dns_soa_getexpire(dns_rdata_t *rdata) {
  77         return soa_get(rdata, 12);
  78 }
  79 isc_uint32_t
  80 dns_soa_getminimum(dns_rdata_t *rdata) {
  81         return soa_get(rdata, 16);
  82 }
  83
  84 static void
  85 soa_set(dns_rdata_t *rdata, isc_uint32_t val, int offset) {
  86         INSIST(rdata->type == dns_rdatatype_soa);
  87         INSIST(rdata->length >= 20);
  88         INSIST(offset >= 0 && offset <= 16);
  89         encode_uint32(val, rdata->data + rdata->length - 20 + offset);
  90 }
  91
  92 void
  93 dns_soa_setserial(isc_uint32_t val, dns_rdata_t *rdata) {
  94         soa_set(rdata, val, 0);
  95 }
  96 void
  97 dns_soa_setrefresh(isc_uint32_t val, dns_rdata_t *rdata) {
  98         soa_set(rdata, val, 4);
  99 }
 100 void
 101 dns_soa_setretry(isc_uint32_t val, dns_rdata_t *rdata) {
 102         soa_set(rdata, val, 8);
 103 }
 104 void
 105 dns_soa_setexpire(isc_uint32_t val, dns_rdata_t *rdata) {
 106         soa_set(rdata, val, 12);
 107 }
 108 void
 109 dns_soa_setminimum(isc_uint32_t val, dns_rdata_t *rdata) {
 110         soa_set(rdata, val, 16);
 111 }