1 /* $NetBSD: soa.c,v 1.6 2022/09/23 12:15:30 christos Exp $ */ 2 3 /* 4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC") 5 * 6 * SPDX-License-Identifier: MPL-2.0 7 * 8 * This Source Code Form is subject to the terms of the Mozilla Public 9 * License, v. 2.0. If a copy of the MPL was not distributed with this 10 * file, you can obtain one at https://mozilla.org/MPL/2.0/. 11 * 12 * See the COPYRIGHT file distributed with this work for additional 13 * information regarding copyright ownership. 14 */ 15 16 /*! \file */ 17 18 #include <inttypes.h> 19 #include <string.h> 20 21 #include <isc/buffer.h> 22 #include <isc/util.h> 23 24 #include <dns/rdata.h> 25 #include <dns/rdatastruct.h> 26 #include <dns/soa.h> 27 28 static uint32_t 29 decode_uint32(unsigned char *p) { 30 return (((uint32_t)p[0] << 24) + ((uint32_t)p[1] << 16) + 31 ((uint32_t)p[2] << 8) + ((uint32_t)p[3] << 0)); 32 } 33 34 static void 35 encode_uint32(uint32_t val, unsigned char *p) { 36 p[0] = (uint8_t)(val >> 24); 37 p[1] = (uint8_t)(val >> 16); 38 p[2] = (uint8_t)(val >> 8); 39 p[3] = (uint8_t)(val >> 0); 40 } 41 42 static uint32_t 43 soa_get(dns_rdata_t *rdata, int offset) { 44 INSIST(rdata->type == dns_rdatatype_soa); 45 /* 46 * Locate the field within the SOA RDATA based 47 * on its position relative to the end of the data. 48 * 49 * This is a bit of a kludge, but the alternative approach of 50 * using dns_rdata_tostruct() and dns_rdata_fromstruct() would 51 * involve a lot of unnecessary work (like building domain 52 * names and allocating temporary memory) when all we really 53 * want to do is to get 32 bits of fixed-sized data. 54 */ 55 INSIST(rdata->length >= 20); 56 INSIST(offset >= 0 && offset <= 16); 57 return (decode_uint32(rdata->data + rdata->length - 20 + offset)); 58 } 59 60 isc_result_t 61 dns_soa_buildrdata(const dns_name_t *origin, const dns_name_t *contact, 62 dns_rdataclass_t rdclass, uint32_t serial, uint32_t refresh, 63 uint32_t retry, uint32_t expire, uint32_t minimum, 64 unsigned char *buffer, dns_rdata_t *rdata) { 65 dns_rdata_soa_t soa; 66 isc_buffer_t rdatabuf; 67 68 REQUIRE(origin != NULL); 69 REQUIRE(contact != NULL); 70 71 memset(buffer, 0, DNS_SOA_BUFFERSIZE); 72 isc_buffer_init(&rdatabuf, buffer, DNS_SOA_BUFFERSIZE); 73 74 soa.common.rdtype = dns_rdatatype_soa; 75 soa.common.rdclass = rdclass; 76 soa.mctx = NULL; 77 soa.serial = serial; 78 soa.refresh = refresh; 79 soa.retry = retry; 80 soa.expire = expire; 81 soa.minimum = minimum; 82 dns_name_init(&soa.origin, NULL); 83 dns_name_clone(origin, &soa.origin); 84 dns_name_init(&soa.contact, NULL); 85 dns_name_clone(contact, &soa.contact); 86 87 return (dns_rdata_fromstruct(rdata, rdclass, dns_rdatatype_soa, &soa, 88 &rdatabuf)); 89 } 90 91 uint32_t 92 dns_soa_getserial(dns_rdata_t *rdata) { 93 return (soa_get(rdata, 0)); 94 } 95 uint32_t 96 dns_soa_getrefresh(dns_rdata_t *rdata) { 97 return (soa_get(rdata, 4)); 98 } 99 uint32_t 100 dns_soa_getretry(dns_rdata_t *rdata) { 101 return (soa_get(rdata, 8)); 102 } 103 uint32_t 104 dns_soa_getexpire(dns_rdata_t *rdata) { 105 return (soa_get(rdata, 12)); 106 } 107 uint32_t 108 dns_soa_getminimum(dns_rdata_t *rdata) { 109 return (soa_get(rdata, 16)); 110 } 111 112 static void 113 soa_set(dns_rdata_t *rdata, uint32_t val, int offset) { 114 INSIST(rdata->type == dns_rdatatype_soa); 115 INSIST(rdata->length >= 20); 116 INSIST(offset >= 0 && offset <= 16); 117 encode_uint32(val, rdata->data + rdata->length - 20 + offset); 118 } 119 120 void 121 dns_soa_setserial(uint32_t val, dns_rdata_t *rdata) { 122 soa_set(rdata, val, 0); 123 } 124 void 125 dns_soa_setrefresh(uint32_t val, dns_rdata_t *rdata) { 126 soa_set(rdata, val, 4); 127 } 128 void 129 dns_soa_setretry(uint32_t val, dns_rdata_t *rdata) { 130 soa_set(rdata, val, 8); 131 } 132 void 133 dns_soa_setexpire(uint32_t val, dns_rdata_t *rdata) { 134 soa_set(rdata, val, 12); 135 } 136 void 137 dns_soa_setminimum(uint32_t val, dns_rdata_t *rdata) { 138 soa_set(rdata, val, 16); 139 } 140