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