diff options
Diffstat (limited to 'lib/dns/soa.c')
| -rw-r--r-- | lib/dns/soa.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/lib/dns/soa.c b/lib/dns/soa.c new file mode 100644 index 0000000..ca5ca88 --- /dev/null +++ b/lib/dns/soa.c @@ -0,0 +1,137 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * SPDX-License-Identifier: MPL-2.0 + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, you can obtain one at https://mozilla.org/MPL/2.0/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +/*! \file */ + +#include <inttypes.h> +#include <string.h> + +#include <isc/buffer.h> +#include <isc/util.h> + +#include <dns/rdata.h> +#include <dns/rdatastruct.h> +#include <dns/soa.h> + +static uint32_t +decode_uint32(unsigned char *p) { + return (((uint32_t)p[0] << 24) + ((uint32_t)p[1] << 16) + + ((uint32_t)p[2] << 8) + ((uint32_t)p[3] << 0)); +} + +static void +encode_uint32(uint32_t val, unsigned char *p) { + p[0] = (uint8_t)(val >> 24); + p[1] = (uint8_t)(val >> 16); + p[2] = (uint8_t)(val >> 8); + p[3] = (uint8_t)(val >> 0); +} + +static uint32_t +soa_get(dns_rdata_t *rdata, int offset) { + INSIST(rdata->type == dns_rdatatype_soa); + /* + * Locate the field within the SOA RDATA based + * on its position relative to the end of the data. + * + * This is a bit of a kludge, but the alternative approach of + * using dns_rdata_tostruct() and dns_rdata_fromstruct() would + * involve a lot of unnecessary work (like building domain + * names and allocating temporary memory) when all we really + * want to do is to get 32 bits of fixed-sized data. + */ + INSIST(rdata->length >= 20); + INSIST(offset >= 0 && offset <= 16); + return (decode_uint32(rdata->data + rdata->length - 20 + offset)); +} + +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) { + dns_rdata_soa_t soa; + isc_buffer_t rdatabuf; + + REQUIRE(origin != NULL); + REQUIRE(contact != NULL); + + memset(buffer, 0, DNS_SOA_BUFFERSIZE); + isc_buffer_init(&rdatabuf, buffer, DNS_SOA_BUFFERSIZE); + + soa.common.rdtype = dns_rdatatype_soa; + soa.common.rdclass = rdclass; + soa.mctx = NULL; + soa.serial = serial; + soa.refresh = refresh; + soa.retry = retry; + soa.expire = expire; + soa.minimum = minimum; + dns_name_init(&soa.origin, NULL); + dns_name_clone(origin, &soa.origin); + dns_name_init(&soa.contact, NULL); + dns_name_clone(contact, &soa.contact); + + return (dns_rdata_fromstruct(rdata, rdclass, dns_rdatatype_soa, &soa, + &rdatabuf)); +} + +uint32_t +dns_soa_getserial(dns_rdata_t *rdata) { + return (soa_get(rdata, 0)); +} +uint32_t +dns_soa_getrefresh(dns_rdata_t *rdata) { + return (soa_get(rdata, 4)); +} +uint32_t +dns_soa_getretry(dns_rdata_t *rdata) { + return (soa_get(rdata, 8)); +} +uint32_t +dns_soa_getexpire(dns_rdata_t *rdata) { + return (soa_get(rdata, 12)); +} +uint32_t +dns_soa_getminimum(dns_rdata_t *rdata) { + return (soa_get(rdata, 16)); +} + +static void +soa_set(dns_rdata_t *rdata, uint32_t val, int offset) { + INSIST(rdata->type == dns_rdatatype_soa); + INSIST(rdata->length >= 20); + INSIST(offset >= 0 && offset <= 16); + encode_uint32(val, rdata->data + rdata->length - 20 + offset); +} + +void +dns_soa_setserial(uint32_t val, dns_rdata_t *rdata) { + soa_set(rdata, val, 0); +} +void +dns_soa_setrefresh(uint32_t val, dns_rdata_t *rdata) { + soa_set(rdata, val, 4); +} +void +dns_soa_setretry(uint32_t val, dns_rdata_t *rdata) { + soa_set(rdata, val, 8); +} +void +dns_soa_setexpire(uint32_t val, dns_rdata_t *rdata) { + soa_set(rdata, val, 12); +} +void +dns_soa_setminimum(uint32_t val, dns_rdata_t *rdata) { + soa_set(rdata, val, 16); +} |