1 files changed, 142 insertions, 0 deletions
diff --git a/lib/dns/soa.c b/lib/dns/soa.c
new file mode 100644
index 0000000..9be3467
--- /dev/null
+++ b/lib/dns/soa.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * 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 http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+
+/*! \file */
+
+#include <config.h>
+
+#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 inline uint32_t
+decode_uint32(unsigned char *p) {
+	return ((p[0] << 24) +
+		(p[1] << 16) +
+		(p[2] <<  8) +
+		(p[3] <<  0));
+}
+
+static inline 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(dns_name_t *origin, 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);
+}