1 files changed, 277 insertions, 0 deletions
diff --git a/lib/dns/nsec.c b/lib/dns/nsec.c
new file mode 100644
index 0000000..53a3b5e
--- /dev/null
+++ b/lib/dns/nsec.c
@@ -0,0 +1,277 @@
+/*
+ * Copyright (C) 2004, 2005, 2007, 2008  Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (C) 1999-2001, 2003  Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* $Id: nsec.c,v 1.11 2008/09/25 04:02:38 tbox Exp $ */
+
+/*! \file */
+
+#include <config.h>
+
+#include <isc/string.h>
+#include <isc/util.h>
+
+#include <dns/db.h>
+#include <dns/nsec.h>
+#include <dns/rdata.h>
+#include <dns/rdatalist.h>
+#include <dns/rdataset.h>
+#include <dns/rdatasetiter.h>
+#include <dns/rdatastruct.h>
+#include <dns/result.h>
+
+#include <dst/dst.h>
+
+#define RETERR(x) do { \
+	result = (x); \
+	if (result != ISC_R_SUCCESS) \
+		goto failure; \
+	} while (0)
+
+static void
+set_bit(unsigned char *array, unsigned int index, unsigned int bit) {
+	unsigned int shift, mask;
+
+	shift = 7 - (index % 8);
+	mask = 1 << shift;
+
+	if (bit != 0)
+		array[index / 8] |= mask;
+	else
+		array[index / 8] &= (~mask & 0xFF);
+}
+
+static unsigned int
+bit_isset(unsigned char *array, unsigned int index) {
+	unsigned int byte, shift, mask;
+
+	byte = array[index / 8];
+	shift = 7 - (index % 8);
+	mask = 1 << shift;
+
+	return ((byte & mask) != 0);
+}
+
+isc_result_t
+dns_nsec_buildrdata(dns_db_t *db, dns_dbversion_t *version,
+		    dns_dbnode_t *node, dns_name_t *target,
+		    unsigned char *buffer, dns_rdata_t *rdata)
+{
+	isc_result_t result;
+	dns_rdataset_t rdataset;
+	isc_region_t r;
+	unsigned int i, window;
+	int octet;
+
+	unsigned char *nsec_bits, *bm;
+	unsigned int max_type;
+	dns_rdatasetiter_t *rdsiter;
+
+	memset(buffer, 0, DNS_NSEC_BUFFERSIZE);
+	dns_name_toregion(target, &r);
+	memcpy(buffer, r.base, r.length);
+	r.base = buffer;
+	/*
+	 * Use the end of the space for a raw bitmap leaving enough
+	 * space for the window identifiers and length octets.
+	 */
+	bm = r.base + r.length + 512;
+	nsec_bits = r.base + r.length;
+	set_bit(bm, dns_rdatatype_rrsig, 1);
+	set_bit(bm, dns_rdatatype_nsec, 1);
+	max_type = dns_rdatatype_nsec;
+	dns_rdataset_init(&rdataset);
+	rdsiter = NULL;
+	result = dns_db_allrdatasets(db, node, version, 0, &rdsiter);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	for (result = dns_rdatasetiter_first(rdsiter);
+	     result == ISC_R_SUCCESS;
+	     result = dns_rdatasetiter_next(rdsiter))
+	{
+		dns_rdatasetiter_current(rdsiter, &rdataset);
+		if (rdataset.type != dns_rdatatype_nsec &&
+		    rdataset.type != dns_rdatatype_nsec3 &&
+		    rdataset.type != dns_rdatatype_rrsig) {
+			if (rdataset.type > max_type)
+				max_type = rdataset.type;
+			set_bit(bm, rdataset.type, 1);
+		}
+		dns_rdataset_disassociate(&rdataset);
+	}
+
+	/*
+	 * At zone cuts, deny the existence of glue in the parent zone.
+	 */
+	if (bit_isset(bm, dns_rdatatype_ns) &&
+	    ! bit_isset(bm, dns_rdatatype_soa)) {
+		for (i = 0; i <= max_type; i++) {
+			if (bit_isset(bm, i) &&
+			    ! dns_rdatatype_iszonecutauth((dns_rdatatype_t)i))
+				set_bit(bm, i, 0);
+		}
+	}
+
+	dns_rdatasetiter_destroy(&rdsiter);
+	if (result != ISC_R_NOMORE)
+		return (result);
+
+	for (window = 0; window < 256; window++) {
+		if (window * 256 > max_type)
+			break;
+		for (octet = 31; octet >= 0; octet--)
+			if (bm[window * 32 + octet] != 0)
+				break;
+		if (octet < 0)
+			continue;
+		nsec_bits[0] = window;
+		nsec_bits[1] = octet + 1;
+		/*
+		 * Note: potential overlapping move.
+		 */
+		memmove(&nsec_bits[2], &bm[window * 32], octet + 1);
+		nsec_bits += 3 + octet;
+	}
+	r.length = nsec_bits - r.base;
+	INSIST(r.length <= DNS_NSEC_BUFFERSIZE);
+	dns_rdata_fromregion(rdata,
+			     dns_db_class(db),
+			     dns_rdatatype_nsec,
+			     &r);
+
+	return (ISC_R_SUCCESS);
+}
+
+
+isc_result_t
+dns_nsec_build(dns_db_t *db, dns_dbversion_t *version, dns_dbnode_t *node,
+	       dns_name_t *target, dns_ttl_t ttl)
+{
+	isc_result_t result;
+	dns_rdata_t rdata = DNS_RDATA_INIT;
+	unsigned char data[DNS_NSEC_BUFFERSIZE];
+	dns_rdatalist_t rdatalist;
+	dns_rdataset_t rdataset;
+
+	dns_rdataset_init(&rdataset);
+	dns_rdata_init(&rdata);
+
+	RETERR(dns_nsec_buildrdata(db, version, node, target, data, &rdata));
+
+	rdatalist.rdclass = dns_db_class(db);
+	rdatalist.type = dns_rdatatype_nsec;
+	rdatalist.covers = 0;
+	rdatalist.ttl = ttl;
+	ISC_LIST_INIT(rdatalist.rdata);
+	ISC_LIST_APPEND(rdatalist.rdata, &rdata, link);
+	RETERR(dns_rdatalist_tordataset(&rdatalist, &rdataset));
+	result = dns_db_addrdataset(db, node, version, 0, &rdataset,
+				    0, NULL);
+	if (result == DNS_R_UNCHANGED)
+		result = ISC_R_SUCCESS;
+	RETERR(result);
+ failure:
+	if (dns_rdataset_isassociated(&rdataset))
+		dns_rdataset_disassociate(&rdataset);
+	return (result);
+}
+
+isc_boolean_t
+dns_nsec_typepresent(dns_rdata_t *nsec, dns_rdatatype_t type) {
+	dns_rdata_nsec_t nsecstruct;
+	isc_result_t result;
+	isc_boolean_t present;
+	unsigned int i, len, window;
+
+	REQUIRE(nsec != NULL);
+	REQUIRE(nsec->type == dns_rdatatype_nsec);
+
+	/* This should never fail */
+	result = dns_rdata_tostruct(nsec, &nsecstruct, NULL);
+	INSIST(result == ISC_R_SUCCESS);
+
+	present = ISC_FALSE;
+	for (i = 0; i < nsecstruct.len; i += len) {
+		INSIST(i + 2 <= nsecstruct.len);
+		window = nsecstruct.typebits[i];
+		len = nsecstruct.typebits[i + 1];
+		INSIST(len > 0 && len <= 32);
+		i += 2;
+		INSIST(i + len <= nsecstruct.len);
+		if (window * 256 > type)
+			break;
+		if ((window + 1) * 256 <= type)
+			continue;
+		if (type < (window * 256) + len * 8)
+			present = ISC_TF(bit_isset(&nsecstruct.typebits[i],
+						   type % 256));
+		break;
+	}
+	dns_rdata_freestruct(&nsec);
+	return (present);
+}
+
+isc_result_t
+dns_nsec_nseconly(dns_db_t *db, dns_dbversion_t *version,
+		  isc_boolean_t *answer)
+{
+	dns_dbnode_t *node = NULL;
+	dns_rdataset_t rdataset;
+	dns_rdata_dnskey_t dnskey;
+	isc_result_t result;
+
+	REQUIRE(answer != NULL);
+
+	dns_rdataset_init(&rdataset);
+
+	result = dns_db_getoriginnode(db, &node);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+
+	result = dns_db_findrdataset(db, node, version, dns_rdatatype_dnskey,
+				     0, 0, &rdataset, NULL);
+	dns_db_detachnode(db, &node);
+
+	if (result == ISC_R_NOTFOUND) {
+		*answer = ISC_FALSE;
+		return (ISC_R_SUCCESS);
+	}
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	for (result = dns_rdataset_first(&rdataset);
+	     result == ISC_R_SUCCESS;
+	     result = dns_rdataset_next(&rdataset)) {
+		dns_rdata_t rdata = DNS_RDATA_INIT;
+
+		dns_rdataset_current(&rdataset, &rdata);
+		result = dns_rdata_tostruct(&rdata, &dnskey, NULL);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+		if (dnskey.algorithm == DST_ALG_RSAMD5 ||
+		    dnskey.algorithm == DST_ALG_RSASHA1 ||
+		    dnskey.algorithm == DST_ALG_DSA ||
+		    dnskey.algorithm == DST_ALG_ECC)
+			break;
+	}
+	dns_rdataset_disassociate(&rdataset);
+	if (result == ISC_R_SUCCESS)
+		*answer = ISC_TRUE;
+	if (result == ISC_R_NOMORE) {
+		*answer = ISC_FALSE;
+		result = ISC_R_SUCCESS;
+	}
+	return (result);
+}