xref: /dports/dns/getdns/getdns-1.5.2/src/dnssec.c

/**
 *
 * /brief functions for DNSSEC
 *
 * In this file, the "dnssec_return_validation_chain" extension is implemented
 * (with the _getdns_get_validation_chain() function)
 * Also the function getdns_validate_dnssec is implemented.
 * DNSSEC validation as a stub combines those two functionalities, by first
 * fetching all the records that are necessary to be able to validate a
 * request (i.e. the "dnssec_return_validation_chain" extension) and then
 * performing DNSSEC validation for a request with those support records
 * (and a trust anchor of course).
 */

/*
 * Copyright (c) 2013, NLnet Labs, Verisign, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * * Neither the names of the copyright holders nor the
 *   names of its contributors may be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL Verisign, Inc. BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * From the API:
 *
 * The "dnssec_return_validation_chain" extension as explained in section 3.1:
 *
 *	Applications that want to do their own validation will want to have the
 *	DNSSEC-related records for a particular response. Use the
 *	dnssec_return_validation_chain extension. The extension's value
 *	(an int) is set to GETDNS_EXTENSION_TRUE to cause a set of additional
 *	DNSSEC-related records needed for validation to be returned in the
 *	response object. This set comes as validation_chain (a list) at the top
 *	level of the response object. This list includes all resource record
 *	dicts for all the resource records (DS, DNSKEY and their RRSIGs) that
 *	are needed to perform the validation from the root up.
 *
 *
 * The getdns_validate_dnssec() function as explained in section 7:
 *
 *	If an application wants the API do perform DNSSEC validation without
 *	using the extensions, it can use the getdns_validate_dnssec() helper
 *	function.
 *
 *	getdns_return_t
 *	getdns_validate_dnssec(
 *		getdns_list     *record_to_validate,
 *		getdns_list     *bundle_of_support_records,
 *		getdns_list     *trust_anchor_records
 *	);
 *
 *	The record_to_validate is the resource record being validated together
 *	with the associated signatures. The API will use the resource records
 *	in bundle_of_support_records to construct the validation chain and the
 *	DNSKEY or DS records in trust_anchor_records as trust anchors. The
 * 	function returns one of GETDNS_DNSSEC_SECURE, GETDNS_DNSSEC_BOGUS,
 *	GETDNS_DNSSEC_INDETERMINATE, or GETDNS_DNSSEC_INSECURE.
 */

/* Outline of operations in this file
 * ==================================
 *
 * Data structure to represent the delegation/referral hierarchy
 * -------------------------------------------------------------
 * Both the "dnssec_return_validation_chain" extension, and the
 * getdns_validate_dnssec() function use the same structs to represent the
 * involved pieces of the DNS in a hierarchical manner.
 *
 * However, the tree is not represented from the root, but from the RRsets that
 * need to be validated.  The RRset to validate is a member of the chain_head
 * struct for this.  The chain_head struct has a "next" member to form a linked
 * list of RRsets to validate.
 *
 * The chain_head struct also has a "parent" member to a linked list of
 * chain_node structs (linked with the "parent" member of those chain_nodes).
 * For each label in the name of the rrset in a chain_head, is a chain_node,
 * all the way to the root.  The last chain_node is thus always the root, for
 * every chain_head.
 *
 * The construction functions for this datastructure make sure there is always
 * a single chain_node representing the same name.  They also make sure space
 * for chain_head + the number of extra chain_nodes needed is allocated in a
 * single region, so that on destruction one only has to free the chain_heads.
 *
 * A chain_node contains two RRset members, "dnskey" and "ds" which represent
 * the potential client side DNSKEYs and the parent side DS records of a
 * potential zonecut at this point.  Whether or not there is an actual zone
 * cut is determined separately.  With the "dnssec_return_validation_chain"
 * extension by scheduling queries, and with the getdns_validation_dnssec()
 * function by provisioning the support records at the chain nodes.
 *
 * In the construction functions a chain_head is created for every RRset in
 * the answer and authority section of a given packet (except for synthesized
 * CNAMEs).  Furthermore, if the queries for name/class/type is not in the
 * packet, a chain_head for the non-existent rrset is created too, to that
 * it will be evaluated for non-existence later in the validation process.
 *
 * The chain_head and chain_node structs are defined in section:
 * "Validation Chain Data Structs".  The functions to construct the hierarchy
 * are defined in section "Validation Chain Construction".  When the
 * construction functions are called for the purpose of the
 * "dnssec_return_validation_chain" extension, queries to provision the
 * chain_nodes are scheduled.  Function theretofore are in section:
 * "Schedule Queries to Provision Validation Chain"
 *
 *
 * _getdns_rrset
 * ------------
 * RRsets used in the structure described above are represented by the
 * _getdns_rrset struct.  They consist of name/rr_class and rr_type members
 * plus a reference to the wireformat packet that should contain the RRset.
 *
 * The actual RR's in the rrset and the signatures are only accessed via
 * iterators; substantiated with the rrtype_iter struct to iterate over RRs
 * in a _getdns_rrset, and the rrsig_iter to iterate over the RRSIGs covering
 * the RRs in the _getdns_rrset.
 *
 * The _getdns_rrsets are already equipped with name/rr_class and rr_type when
 * constructing the linked list of chain_nodes up to the root for a chain_head.
 * They are substantiated with the wireformat packets that are returned with
 * the queries that were sheduled in the context of the
 * "dnssec_return_validation_chain" extension.
 *
 * Note that the NSEC(3) RRsets proving the non-existance of a _getdns_rrset
 * can be found by processing that _getdns_rrset, as it contains the pointer
 * to the wireformat data that should either contain the RRset or the proof
 * of non-existance.
 *
 * The getdns_validate_dnssec() function, after it constructed the chain_heads
 * hierarchy, creates an artificial packet for the support records and equips
 * all the ds and dnskey _getdns_rrsets on the chain_nodes with this packet.
 *
 * The _getdns_rrset + support function and data types are defined in section:
 * "_getdns_rrset + Support Iterators"
 *
 *
 * Validation
 * ----------
 * Validation of a constructed chain is done by the
 * chain_set_netreq_dnssec_status() function when validating in stub mode.
 * And with the chain_validate_dnssec() function when using the
 * getdns_validate_dnssec() function.  They are the same, except that
 * chain_set_netreq_dnssec_status() evaluates DNSSEC status per network
 * request and chain_validate_dnssec() does it for the whole chain.
 *
 * They both evaluate the DNSSEC status for each head in turn.  The worst
 * DNSSEC status determines the status of all heads evaluated.  Where
 * INSECURE is worse than SECURE, and BOGUS is worse than INSECURE.
 *
 * For each head, the closest (most labels still a parent of the head's name)
 * trust anchor is tried.  Without fitting trust anchors, DNSSEC_INDETERMINATE
 * is returned.
 *
 * Security status for a head (with a specific trust anchor) is evaluated by
 * first finding a authenticated keyset from the parent chain_nodes, and then
 * evaluating the rrset of the head (existent or not) with that keyset.
 *
 * Functions that implement DNSSEC validation are in section:
 * "DNSSEC Validation".
 *
 * Many functions are of key verification boolean return type; e.g.
 * key_proves_nonexistance(), ds_authenticates_keys(), a_key_signed_rrset()
 * These will return the keytag identifying the key that was used to
 * authenticate + 0x10000 to allow keytag 0.
 *
 * These returned keytag's are used later with function
 * append_rrs2val_chain_list() to return a "dnssec_validation_chain" that
 * enumerates a single RRSIG per RRset.  This can be found in section:
 * "dnssec_return_validation_chain Extension".
 */

#include "config.h"
#include "debug.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <ctype.h>
#include "getdns/getdns.h"
#include "context.h"
#include "util-internal.h"
#include "types-internal.h"
#include "dnssec.h"
#include "rr-dict.h"
#include "gldns/str2wire.h"
#include "gldns/wire2str.h"
#include "gldns/keyraw.h"
#include "gldns/parseutil.h"
#include "general.h"
#include "dict.h"
#include "list.h"
#include "util/val_secalgo.h"
#include "anchor.h"
#include "tls.h"

#define SIGNATURE_VERIFIED         0x10000
#define NSEC3_ITERATION_COUNT_HIGH 0x20000
#define NO_SUPPORTED_ALGORITHMS    0x40000

/*******************  Frequently Used Utility Functions  *********************
 *****************************************************************************/

static inline size_t _dname_len(const uint8_t *name)
{
	const uint8_t *p;
	for (p = name; *p; p += *p + 1)
		/* pass */
		;
	return p - name + 1;
}

static inline size_t _dname_label_count(const uint8_t *name)
{
	size_t c;
	for (c = 0; *name; name += *name + 1, c++)
		/* pass */
		;
	return c;
}

static inline int _dname_equal(const uint8_t *left, const uint8_t *right)
{
	return _getdns_dname_equal(left, right);
}

static int _dname_is_parent(
    const uint8_t * const parent, const uint8_t *subdomain)
{
	if (*parent == 0)
		return 1;

	else while (*subdomain) {
		if (_dname_equal(parent, subdomain))
			return 1;

		subdomain += *subdomain + 1;
	}
	return 0;
}

static uint8_t *_dname_label_copy(uint8_t *dst, const uint8_t *src, size_t dst_len)
{
	uint8_t *r = dst, i;

	if (!src || (size_t)*src + 1 > dst_len)
		return NULL;

	for (i = (*dst++ = *src++); i ; i--)
		*dst++ = tolower(*src++);

	return r;
}


/* Fills the array pointed to by labels (of at least 128 uint8_t * pointers)
 * with pointers to labels in given dname in reversed order.  So that
 * labels[0] will point to the root.
 * labels[1] will point to the tld etc.
 * A pointer just past the last assigned array element will be returned.
 *
 * So if dname would be "www.getdnsapi.net"
 * labels[0] will be "."
 * labels[1] will be "net."
 * labels[2] will be "getdnsapi.net."
 * labels[3] will be "www.getdnsapi.net."
 * The returned value will be &labels[4]
 */
static const uint8_t **reverse_labels(
    const uint8_t *dname, const uint8_t **labels)
{
	if (*dname)
		labels = reverse_labels(dname + *dname + 1, labels);
	*labels = dname;
	return labels + 1;
}

static const uint8_t *dname_shared_parent(
    const uint8_t *left, const uint8_t *right)
{
	const uint8_t *llabels[128], *rlabels[128], **last_llabel, **last_rlabel,
		**llabel, **rlabel, *l, *r;
	uint8_t sz;

	last_llabel = reverse_labels(left, llabels);
	last_rlabel = reverse_labels(right, rlabels);

	/* Always at least one label (the root) */
	assert(last_llabel > llabels);
	assert(last_rlabel > rlabels);
	assert(*llabels[0] == 0);
	assert(*rlabels[0] == 0);

	for ( llabel = &llabels[1], rlabel = &rlabels[1]
	    ; llabel < last_llabel
	    ; llabel++, rlabel++ ) {

		sz = **llabel;
		if (   rlabel == last_rlabel
		    || **llabel != **rlabel)
			return llabel[-1];

		for (l = *llabel+1, r = *rlabel+1; sz; l++, r++, sz-- )
			if (*l != *r && tolower((unsigned char)*l) !=
					tolower((unsigned char)*r))
				return llabel[-1];
	}
	return llabel[-1];
}

static int dname_compare(const uint8_t *left, const uint8_t *right)
{
	const uint8_t *llabels[128], *rlabels[128], **last_llabel, **last_rlabel,
		**llabel, **rlabel, *l, *r;
	uint8_t lsz, rsz;

	last_llabel = reverse_labels(left, llabels);
	last_rlabel = reverse_labels(right, rlabels);

	for ( llabel = llabels, rlabel = rlabels
	    ; llabel < last_llabel
	    ; llabel++, rlabel++ ) {

		if (rlabel == last_rlabel)
			return 1;

		for ( l = *llabel, lsz = *l++, r = *rlabel, rsz = *r++
		    ; lsz; l++, r++, lsz--, rsz-- ) {

			/* No compression pointers here */
			assert(lsz <= 63);
			assert(rsz <= 63);

			if (!rsz)
				return 1;
			if (*l != *r && tolower((unsigned char)*l) !=
					tolower((unsigned char)*r)) {
				if (tolower((unsigned char)*l) <
				    tolower((unsigned char)*r))
					return -1;
				return 1;
			}
		}
		if (rsz)
			return -1;
	}
	return rlabel == last_rlabel ? 0 : -1;
}

static int bitmap_has_type(_getdns_rdf_iter *bitmap, uint16_t rr_type)
{
	const uint8_t *dptr, *dend;
	uint8_t window  = rr_type >> 8;
	uint8_t subtype = rr_type & 0xFF;

	if (!bitmap || (dptr = bitmap->pos) == (dend = bitmap->nxt))
		return 0;

	/* Type Bitmap = ( Window Block # | Bitmap Length | Bitmap ) +
	 *                 dptr[0]          dptr[1]         dptr[2:]
	 */
	while (dptr < dend && dptr[0] <= window) {
		if (dptr[0] == window && subtype / 8 < dptr[1] &&
		    dptr + dptr[1] + 2 <= dend)
			return dptr[2 + subtype / 8] & (0x80 >> (subtype % 8));
		dptr += dptr[1] + 2; /* next window */
	}
	return 0;
}

#if defined(SEC_DEBUG) && SEC_DEBUG
static inline void debug_sec_print_rr(const char *msg, _getdns_rr_iter *rr)
{
	char str_spc[8192], *str = str_spc;
	size_t str_len = sizeof(str_spc);
	const uint8_t *data = rr->pos;
	size_t data_len = rr->nxt - rr->pos;

	if (!rr || !rr->pos) {
		DEBUG_SEC("%s<nil>\n", msg);
		return;
	}
	(void) gldns_wire2str_rr_scan(
	    (UNCONST_UINT8_p *) &data, &data_len, &str, &str_len,
	    (UNCONST_UINT8_p) rr->pkt, rr->pkt_end - rr->pkt);
	DEBUG_SEC("%s%s", msg, str_spc);
}
static inline void debug_sec_print_dname(const char *msg, const uint8_t *label)
{
	char str[1024];

	if (label && gldns_wire2str_dname_buf(
	    (UNCONST_UINT8_p)label, 256, str, sizeof(str)))
		DEBUG_SEC("%s%s\n", msg, str);
	else
		DEBUG_SEC("%s<nil>\n", msg);
}
#else
#define debug_sec_print_rr(...) DEBUG_OFF(__VA_ARGS__)
#define debug_sec_print_dname(...) DEBUG_OFF(__VA_ARGS__)
#define debug_sec_print_pkt(...) DEBUG_OFF(__VA_ARGS__)
#endif


/*******************  _getdns_rrset + Support Iterators  **********************
 *****************************************************************************/


#if defined(SEC_DEBUG) && SEC_DEBUG
static void debug_sec_print_rrset(const char *msg, _getdns_rrset *rrset)
{
	char owner[1024];
	char buf_space[2048];
	gldns_buffer buf;
	_getdns_rrtype_iter *rr, rr_space;
	_getdns_rrsig_iter  *rrsig, rrsig_space;
	size_t i;

	if (!rrset) {
		DEBUG_SEC("<nil>");
		return;
	}
	gldns_buffer_init_frm_data(&buf, buf_space, sizeof(buf_space));
	if (gldns_wire2str_dname_buf(
	    (UNCONST_UINT8_p)rrset->name, 256, owner, sizeof(owner)))
		gldns_buffer_printf(&buf, "%s ", owner);
	else	gldns_buffer_printf(&buf, "<nil> ");

	switch (rrset->rr_class) {
	case GETDNS_RRCLASS_IN	: gldns_buffer_printf(&buf, "IN ")  ; break;
	case GETDNS_RRCLASS_CH	: gldns_buffer_printf(&buf, "CH ")  ; break;
	case GETDNS_RRCLASS_HS	: gldns_buffer_printf(&buf, "HS ")  ; break;
	case GETDNS_RRCLASS_NONE: gldns_buffer_printf(&buf, "NONE "); break;
	case GETDNS_RRCLASS_ANY	: gldns_buffer_printf(&buf, "ANY ") ; break;
	default			: gldns_buffer_printf(&buf, "CLASS%d "
						          , rrset->rr_class);
				  break;
	}
	gldns_buffer_printf(&buf, "%s", _getdns_rr_type_name(rrset->rr_type));

	gldns_buffer_printf(&buf, ", rrs:");
	for ( rr = _getdns_rrtype_iter_init(&rr_space, rrset), i = 1
	    ; rr
	    ; rr = _getdns_rrtype_iter_next(rr), i++)
		gldns_buffer_printf(&buf, " %d", (int)i);

	gldns_buffer_printf(&buf, ", rrsigs:");
	for ( rrsig = _getdns_rrsig_iter_init(&rrsig_space, rrset), i = 1
	    ; rrsig
	    ; rrsig = _getdns_rrsig_iter_next(rrsig), i++)
		gldns_buffer_printf(&buf, " %d", (int)i);

	DEBUG_SEC("%s%s\n", msg, buf_space);
}
#else
#define debug_sec_print_rrset(...) DEBUG_OFF(__VA_ARGS__)
#endif


/*********************  Validation Chain Data Structs  ***********************
 *****************************************************************************/

typedef struct chain_head chain_head;
typedef struct chain_node chain_node;

struct chain_head {
	struct mem_funcs  my_mf;

	size_t              lock;

	chain_head         *next;
	chain_node         *parent;
	size_t              node_count; /* Number of nodes attached directly
	                                 * to this head.  For cleaning.  */
	_getdns_rrset       rrset;
	getdns_network_req *netreq;
	int                 signer;

	uint8_t             name_spc[];
};

struct chain_node {
	chain_node  *parent;

	size_t              lock;

	_getdns_rrset       dnskey;
	getdns_network_req *dnskey_req;
	int                 dnskey_signer;

	_getdns_rrset       ds;
	getdns_network_req *ds_req;
	int                 ds_signer;

	chain_head  *chains;
};

/*********************  Validation Chain Construction  ***********************
 *****************************************************************************/

/* When construction is done in the context of stub validation, the requests
 * to equip the chain nodes with their RR sets are done alongside construction.
 * Hence they need to be enumerated before the construction functions.
 */
static void val_chain_sched(chain_head *head, const uint8_t *dname);
static void val_chain_sched_ds(chain_head *head, const uint8_t *dname);
static void val_chain_sched_signer(chain_head *head, _getdns_rrsig_iter *rrsig);

static chain_head *add_rrset2val_chain(const struct mem_funcs *mf,
    chain_head **chain_p, _getdns_rrset *rrset, getdns_network_req *netreq)
{
	chain_head *head;
	const uint8_t *labels[128], **last_label, **label;

	ssize_t     max_labels; /* max labels in common */
	chain_head *max_head;
	chain_node *max_node;

	size_t      dname_len, head_sz, node_count, n;
	const uint8_t *dname;
	uint8_t    *region;
	chain_node *node;

	last_label = reverse_labels(rrset->name, labels);

	/* Try to find a chain with the most overlapping labels.
	 * max_labels will be the number of labels in common from the root
	 *            (so at least one; the root)
	 * max_head   will be the head of the chain with max # labels in common
	 */
	max_head = NULL;
	max_labels = 0;
	for (head = *chain_p; head; head = head->next) {
		/* Also, try to prevent adding double rrsets */
		if (   rrset->rr_class == head->rrset.rr_class
		    && rrset->rr_type  == head->rrset.rr_type
		    && _dname_equal(rrset->name, head->rrset.name)) {

			if (rrset->pkt == head->rrset.pkt &&
			    rrset->pkt_len == head->rrset.pkt_len)
				return NULL;
			else {
				/* Anticipate resubmissions due to
				 * roadblock avoidance */
				head->rrset.pkt = rrset->pkt;
				head->rrset.pkt_len = rrset->pkt_len;
				return head;
			}
		}

		if (   rrset->rr_class == head->rrset.rr_class
		    && rrset->rr_type  == head->rrset.rr_type
		    && rrset->pkt      != head->rrset.pkt
		    && _dname_equal(rrset->name, head->rrset.name)) {
			return NULL;
		}
		for (label = labels; label < last_label; label++) {
			if (! _dname_is_parent(*label, head->rrset.name))
				break;
		}
		if ((ssize_t)(label - labels) > max_labels) {
			max_labels = label - labels;
			max_head = head;
		}
	}
	/* Chain found.  Now set max_node to the point in the chain where nodes
	 *               will be common.
	 */
	if (max_head) {
		for ( node = max_head->parent, n = 0
		    ; node
		    ; node = node->parent, n++);

		for ( n -= max_labels, node = max_head->parent
		    ; n && node
		    ; n--, node = node->parent);

		max_node = node;
	} else
		max_node = NULL;

	/* node_count is the amount of nodes to still allocate.
	 * the last one's parent has to hook into the max_node.
	 */
	dname_len = *labels - last_label[-1] + 1;
	head_sz = (sizeof(chain_head) + dname_len + 7) / 8 * 8;
	node_count = last_label - labels - max_labels;
	DEBUG_SEC( "%"PRIsz" labels in common. %"PRIsz" labels to allocate\n"
	         , max_labels, node_count);

	if (! (region = GETDNS_XMALLOC(*mf, uint8_t, head_sz +
	    node_count * sizeof(chain_node))))
		return NULL;

	/* Append the head on the linked list of heads */
	for (head = *chain_p; head && head->next; head = head->next)
		;
	if  (head)
		head = head->next = (chain_head *)region;
	else
		head = *chain_p   = (chain_head *)region;

	head->my_mf = *mf;
	head->lock = 1;
	head->next = NULL;
	head->rrset.name = head->name_spc;
	memcpy(head->name_spc, rrset->name, dname_len);
	head->rrset.rr_class = rrset->rr_class;
	head->rrset.rr_type = rrset->rr_type;
	head->rrset.pkt = rrset->pkt;
	head->rrset.pkt_len = rrset->pkt_len;
	head->rrset.sections = rrset->sections;
	head->netreq = netreq;
	head->signer = -1;
	head->node_count = node_count;

	if (!node_count) {
		/* When this head has no nodes of itself, it must have found
		 * another head which has nodes for its labels (i.e. max_head)
		 */
		assert(max_head != NULL);

		head->parent = max_head->parent;
		return head;
	}

	/* Initialize the nodes */

	for ( head->parent = node = (chain_node *)(region + head_sz),
	      dname = head->rrset.name
	    ; node_count
	    ; node_count--, node = node->parent =&node[1], dname += *dname + 1) {

		node->lock            = 0;
		node->ds.name         = dname;
		node->dnskey.name     = dname;
		node->ds.rr_class     = head->rrset.rr_class;
		node->dnskey.rr_class = head->rrset.rr_class;
		node->ds.rr_type      = GETDNS_RRTYPE_DS;
		node->dnskey.rr_type  = GETDNS_RRTYPE_DNSKEY;
		node->ds.pkt          = NULL;
		node->ds.pkt_len      = 0;
		node->ds.sections     = head->rrset.sections;
		node->dnskey.pkt      = NULL;
		node->dnskey.pkt_len  = 0;
		node->dnskey.sections = head->rrset.sections;
		node->ds_req          = NULL;
		node->dnskey_req      = NULL;
		node->ds_signer       = -1;
		node->dnskey_signer   = -1;

		node->chains          = *chain_p;
	}
	/* On the first chain, max_node == NULL.
	 * Schedule a root DNSKEY query, we always need that.
	 */
	if (!(node[-1].parent = max_node))
		val_chain_sched(head, (uint8_t *)"\0");

	/* For an NSEC or NSEC3 query, stop at that.  If it is valid it will
	 * have a signature which will be chased.
	 */
	if (head->rrset.rr_type == GETDNS_RRTYPE_NSEC ||
	    head->rrset.rr_type == GETDNS_RRTYPE_NSEC3)
		return head;

	/* Otherwise, schedule key lookups for the tld and sld too. */
	if (!max_node) {
		if (head->node_count > 1)
			val_chain_sched(head, node[-2].ds.name);
		if (head->node_count > 2)
			val_chain_sched(head, node[-3].ds.name);
	} else if ((max_labels == 1 || max_labels == 2) && head->node_count > 0)
		val_chain_sched(head, node[-1].ds.name);
	if (max_labels == 1 && head->node_count > 1)
		val_chain_sched(head, node[-2].ds.name);

	return head;
}

static int is_synthesized_cname(_getdns_rrset *cname)
{
	_getdns_rrset_iter *i, i_spc;
	_getdns_rrset *dname;
	_getdns_rrtype_iter rr_spc, *rr;
	_getdns_rdf_iter rdf_spc, *rdf;
	_getdns_rrtype_iter drr_spc, *drr;
	_getdns_rdf_iter drdf_spc, *drdf;
	uint8_t cname_rdata_spc[256],
	        dname_rdata_spc[256],
		synth_name[256],
	       *synth_name_end = synth_name + sizeof(synth_name) - 1, *s;
	const uint8_t *cname_rdata, *dname_rdata, *c;
	size_t cname_rdata_len = sizeof(cname_rdata_spc),
	       dname_rdata_len = sizeof(dname_rdata_len),
	       cname_labels, dname_labels;

	/* Synthesized CNAMEs don't have RRSIGs */
	if (   cname->rr_type != GETDNS_RRTYPE_CNAME
	    || _getdns_rrset_has_rrsigs(cname))
		return 0;

	/* Get canonical name rdata field */
	if (   !(rr = _getdns_rrtype_iter_init(&rr_spc, cname))
	    || !(rdf = _getdns_rdf_iter_init(&rdf_spc, &rr->rr_i))
	    || !(cname_rdata = _getdns_rdf_if_or_as_decompressed(
			    rdf, cname_rdata_spc, &cname_rdata_len)))
		return 0;

	/* Find a matching DNAME */
	for ( i = _getdns_rrset_iter_init(&i_spc, cname->pkt, cname->pkt_len
	                                        , SECTION_ANSWER)
	    ; i
	    ; i = _getdns_rrset_iter_next(i)) {

		dname = _getdns_rrset_iter_value(i);
		if (   dname->rr_type != GETDNS_RRTYPE_DNAME
		    /* DNAME->owner is parent of CNAME->owner */
		    || !_dname_is_parent(dname->name, cname->name))
			continue;


		dname_labels = _dname_label_count(dname->name);
		cname_labels = _dname_label_count(cname->name);

		/* Synthesize the canonical name.
		 * First copy labels(cname) - labels(dname) labels from
		 * CNAME's owner name, then append DNAME rdata field.
		 * If it matches CNAME's rdata field then it was synthesized
		 * with this DNAME.
		 */
		cname_labels -= dname_labels;
		for ( c = cname->name, s = synth_name
		    ; cname_labels && s +  *c + 1 < synth_name_end
		    ; cname_labels--, c += *c + 1, s += *s + 1 ) {

			memcpy(s, c, *c + 1);
		}
		if (cname_labels)
			continue;

		/* Get DNAME's rdata field */
		if (   !(drr = _getdns_rrtype_iter_init(&drr_spc, dname))
		    || !(drdf=_getdns_rdf_iter_init(&drdf_spc,&drr->rr_i))
		    || !(dname_rdata = _getdns_rdf_if_or_as_decompressed(
				    drdf, dname_rdata_spc, &dname_rdata_len)))
			continue;

		if (s + _dname_len(dname_rdata) > synth_name_end)
			continue;

		memcpy(s, dname_rdata, _dname_len(dname_rdata));
		debug_sec_print_dname("Synthesized name: ", synth_name);
		debug_sec_print_dname("  Canonical name: ", cname_rdata);
		if (_dname_equal(synth_name, cname_rdata))
			return 1;
	}
	return 0;
}

/* Create the validation chain structure for the given packet.
 * When netreq is set, queries will be scheduled for the DS
 * and DNSKEY RR's for the nodes on the validation chain.
 *
 * Scheduling is as follows.
 * If the RRset has a signature, signer name is followed to schedule DS/DNSKEY.
 * Otherwise, if the RRSET is a SOA, owner name is followed to schedule DS
 * Otherwise, if the RRset is a CNAME, a SOA query is scheduled for the parent
 * Otherwise, a SOA query is scheduled for the owner name.
 *
 * When a SOA query was successful, a query for DS will follow for that
 * owner name.
 */
static void add_pkt2val_chain(const struct mem_funcs *mf,
    chain_head **chain_p, uint8_t *pkt, size_t pkt_len,
    getdns_network_req *netreq)
{
	_getdns_rrset_iter *i, i_spc;
	_getdns_rrset *rrset;
	_getdns_rrsig_iter *rrsig, rrsig_spc;
	size_t n_rrsigs;
	chain_head *head;

	assert(pkt);
	assert(pkt_len >= GLDNS_HEADER_SIZE);

	/* For all things with signatures, create a chain */

	/* For all things without signature, find SOA (zonecut) and query DS */

	for ( i = _getdns_rrset_iter_init(&i_spc, pkt, pkt_len
	                                        , SECTION_NO_ADDITIONAL)
	    ; i
	    ; i = _getdns_rrset_iter_next(i)) {

		rrset = _getdns_rrset_iter_value(i);
		debug_sec_print_rrset("rrset: ", rrset);

		/* Schedule validation for everything, except from DNAME
		 * synthesized CNAME's
		 */
		if (is_synthesized_cname(rrset))
			continue;

		if (!(rrsig = _getdns_rrsig_iter_init(&rrsig_spc, rrset))
		    && _getdns_rr_iter_section(&i->rr_i) != SECTION_ANSWER)
			continue; /* No sigs in authority section is okayish */

		if (!(head = add_rrset2val_chain(mf, chain_p, rrset, netreq)))
			continue;

		for ( n_rrsigs = 0; rrsig
		    ; rrsig = _getdns_rrsig_iter_next(rrsig), n_rrsigs++) {

			/* Signature, so lookup DS/DNSKEY at signer's name */
			val_chain_sched_signer(head, rrsig);
		}
		if (n_rrsigs)
			continue;

		/* No signatures found for this RRset */
		if (rrset->rr_type == GETDNS_RRTYPE_SOA)
			val_chain_sched_ds(head, rrset->name);
		else if (rrset->rr_type == GETDNS_RRTYPE_CNAME)
			val_chain_sched_ds(head, rrset->name + *rrset->name + 1);
		else
			val_chain_sched_ds(head, rrset->name);
	}
}

/* For NOERROR/NODATA or NXDOMAIN responses add extra rrset to
 * the validation chain so the denial of existence will be
 * checked eventually.
 * But only if we know the question of course...
 */
static void add_question2val_chain(const struct mem_funcs *mf,
    chain_head **chain_p, uint8_t *pkt, size_t pkt_len,
    const uint8_t *qname, uint16_t qtype, uint16_t qclass,
    getdns_network_req *netreq)
{
	_getdns_rrset_iter *i, i_spc;
	_getdns_rrset *rrset;
	_getdns_rrsig_iter rrsig_spc;
	size_t n_soas;

	_getdns_rrset_spc q_rrset;
	chain_head *head;

	assert(pkt);
	assert(pkt_len >= GLDNS_HEADER_SIZE);
	assert(qname);

	/* First find the canonical name for the question */
	q_rrset.rrset.name     = qname;
	q_rrset.rrset.rr_type  = qtype;
	q_rrset.rrset.rr_class = qclass;
	q_rrset.rrset.pkt      = pkt;
	q_rrset.rrset.pkt_len  = pkt_len;
	q_rrset.rrset.sections = SECTION_ANSWER;

	if (_getdns_initialized_rrset_answer(&q_rrset))
		return;

	/* No answer for the question.  Add a head for this rrset
	 * anyway, to validate proof of non-existance, or to find
	 * proof that the packet is insecure.
	 */
	debug_sec_print_rrset("Adding NX rrset: ", &q_rrset.rrset);
	head = add_rrset2val_chain(mf, chain_p, &q_rrset.rrset, netreq);

	/* Insecure SOA indicating a zonecut in the authority section?
	 * Then schedule a DS query at the zonecut for insecure proof.
	 */
	n_soas = 0;
	for ( i = _getdns_rrset_iter_init(&i_spc, pkt, pkt_len
	                                        , SECTION_AUTHORITY)
	    ; i ; i = _getdns_rrset_iter_next(i)) {
		rrset = _getdns_rrset_iter_value(i);
		debug_sec_print_rrset("rrset: ", rrset);

		if (rrset->rr_type != GETDNS_RRTYPE_SOA)
			continue;

		n_soas += 1;

		if (_getdns_rrsig_iter_init(&rrsig_spc, rrset))
			continue;

		val_chain_sched_ds(head, rrset->name);
	}
	/* No answer and no SOA indicating a zonecut? Find zonecut */
	if (n_soas == 0)
		val_chain_sched_ds(head, q_rrset.rrset.name);
}


/*************  Schedule Queries to Provision Validation Chain ***************
 *****************************************************************************/

static getdns_dict *CD_extension(getdns_dns_req *dnsreq)
{
#ifdef DNSSEC_ROADBLOCK_AVOIDANCE
	return !dnsreq->dnssec_roadblock_avoidance
	     ? dnssec_ok_checking_disabled
	     : !dnsreq->avoid_dnssec_roadblocks
	     ? dnssec_ok_checking_disabled_roadblock_avoidance
	     : dnssec_ok_checking_disabled_avoid_roadblocks;
#else
	(void)dnsreq;
	return dnssec_ok_checking_disabled;
#endif
}

static void check_chain_complete(chain_head *chain);

static chain_head *_dnskey_query(const chain_node *node)
{
	chain_head *head;

	for (head = node->chains; head; head = head->next)
		if (head->rrset.rr_type == GETDNS_RRTYPE_DNSKEY &&
		    head->parent == node)
			return head;
	return NULL;
}

static void val_chain_node_cb(getdns_dns_req *dnsreq);
static void val_chain_sched_node(chain_node *node)
{
	getdns_context *context;
	getdns_eventloop *loop;
	char  name[1024];

	context = node->chains->netreq->owner->context;
	loop    = node->chains->netreq->owner->loop;

	if (!gldns_wire2str_dname_buf(
	    (UNCONST_UINT8_p)node->ds.name, 256, name, sizeof(name)))
		return;

	DEBUG_SEC("schedule DS & DNSKEY lookup for %s\n", name);

	node->lock++;
	if (! node->dnskey_req) {
		chain_head *head;

		/* Reuse the DNSKEY query if this node is scheduled in the
		 * context of validating a DNSKEY query, because libunbound
		 * does not callback from a callback for the same query.
		 */

		if ((head = _dnskey_query(node))) {
			DEBUG_SEC("Found DNSKEY head: %p\n", (void *)head);
			node->dnskey_req     = head->netreq;
			node->dnskey.pkt     = head->netreq->response;
			node->dnskey.pkt_len = head->netreq->response_len;

		} else if (_getdns_general_loop(
		    context, loop, name, GETDNS_RRTYPE_DNSKEY,
		    CD_extension(node->chains->netreq->owner),
		    node, &node->dnskey_req, NULL, val_chain_node_cb))

			node->dnskey_req     = NULL;
	}
	if (! node->ds_req && node->parent /* not root */ &&
	    _getdns_general_loop(context, loop, name, GETDNS_RRTYPE_DS,
	    CD_extension(node->chains->netreq->owner),
	    node, &node->ds_req, NULL, val_chain_node_cb))

		node->ds_req = NULL;

	if (node->lock) node->lock--;
}

static void val_chain_sched(chain_head *head, const uint8_t *dname)
{
	chain_node *node;

	if (!head->netreq)
		return;

	for ( node = head->parent
	    ; node && !_dname_equal(dname, node->ds.name)
	    ; node = node->parent);
	if (node)
		val_chain_sched_node(node);
}

static void val_chain_sched_ds_node(chain_node *node)
{
	getdns_context *context;
	getdns_eventloop *loop;
	char  name[1024];

	context = node->chains->netreq->owner->context;
	loop    = node->chains->netreq->owner->loop;

	if (!gldns_wire2str_dname_buf(
	    (UNCONST_UINT8_p)node->ds.name, 256, name, sizeof(name)))

		return;

	DEBUG_SEC("schedule DS lookup for %s\n", name);

	node->lock++;
	if (! node->ds_req && node->parent /* not root */ &&
	    _getdns_general_loop(context, loop, name, GETDNS_RRTYPE_DS,
	    CD_extension(node->chains->netreq->owner),
	    node, &node->ds_req, NULL, val_chain_node_cb))

		node->ds_req = NULL;

	if (node->lock) node->lock--;
}

static void val_chain_sched_ds(chain_head *head, const uint8_t *dname)
{
	chain_node *node;

	if (!head->netreq)
		return;

	for ( node = head->parent
	    ; node && !_dname_equal(dname, node->ds.name)
	    ; node = node->parent);
	if (node)
		val_chain_sched_ds_node(node);
}

static void val_chain_sched_signer_node(chain_node *node, _getdns_rrsig_iter *rrsig)
{
	_getdns_rdf_iter rdf_spc, *rdf;
	uint8_t  signer_spc[256];
	const uint8_t *signer;
	size_t   signer_len;

	if (!(rdf = _getdns_rdf_iter_init_at(&rdf_spc, &rrsig->rr_i, 7)))
		return;

	if (!(signer = _getdns_rdf_if_or_as_decompressed(
	    rdf, signer_spc, &signer_len)))
		return;

	while (node && !_dname_equal(signer, node->ds.name))
		node = node->parent;
	if (node)
		val_chain_sched_node(node);
}

static void val_chain_sched_signer(chain_head *head, _getdns_rrsig_iter *rrsig)
{
	if (!head->netreq)
		return;

	val_chain_sched_signer_node(head->parent, rrsig);
}

/* Cancel all DS and DNSKEY for subdomains of parent_dname,
 * and also the DNSKEY query at the parent_dname
 */
static void cancel_requests_for_subdomains_of(
    chain_head *head, const uint8_t *parent_dname)
{
	chain_head *next;
	chain_node *node;
	size_t      node_count;

	while (head) {
		next = head->next;

		if (!_dname_is_parent(parent_dname, head->rrset.name)) {
			head = next;
			continue;
		}
		for ( node_count = head->node_count, node = head->parent
		    ; node_count
		    ; node_count--, node = node->parent ) {

			if (!_getdns_netreq_finished(node->dnskey_req)) {
				_getdns_context_cancel_request(
				    node->dnskey_req->owner);
				node->dnskey_req = NULL;
			}

			if (_dname_equal(parent_dname, node->ds.name))
				break;

			if (!_getdns_netreq_finished(node->ds_req)) {
				_getdns_context_cancel_request(
				    node->ds_req->owner);
				node->ds_req = NULL;
			}
		}
		head = next;
	}

}

static int nsec3_matches_name(_getdns_rrset *nsec3, const uint8_t *name);
static int nsec3_covers_name(
    _getdns_rrset *nsec3, const uint8_t *name, int *opt_out);

static int insecure_delegation(_getdns_rrset *ds_rrset)
{
	_getdns_rrset        nsec_rrset;
	_getdns_rrtype_iter *rr, rr_spc;
	_getdns_rrsig_iter   rrsig_spc;
	_getdns_rdf_iter     bitmap_spc, *bitmap;
	_getdns_rrset_iter  *i, i_spc;

	/* For NSEC, an insecure delegation is a NODATA proof for DS */
	nsec_rrset = *ds_rrset;
	nsec_rrset.rr_type = GETDNS_RRTYPE_NSEC;
	if (!_getdns_rrsig_iter_init(&rrsig_spc, &nsec_rrset))
		; /* pass */
	else for ( rr = _getdns_rrtype_iter_init(&rr_spc, &nsec_rrset)
	         ; rr ; rr = _getdns_rrtype_iter_next(rr)) {

		if ((bitmap = _getdns_rdf_iter_init_at( &bitmap_spc
		                                      , &rr->rr_i, 1))
		    &&  bitmap_has_type(bitmap, GETDNS_RRTYPE_NS)
		    && !bitmap_has_type(bitmap, GETDNS_RRTYPE_DS)
		    && _getdns_rrsig_iter_init(&rrsig_spc, &nsec_rrset))
			return 1;
	}

	/* For NSEC3 it is either a NODATA proof with a delegation,
           or a NSEC3 opt-out coverage  */
	for ( i = _getdns_rrset_iter_init(&i_spc, ds_rrset->pkt
	                                        , ds_rrset->pkt_len
	                                        , SECTION_NO_ADDITIONAL)
	    ; i ; i = _getdns_rrset_iter_next(i)) {
		_getdns_rrset *nsec3_rrset = _getdns_rrset_iter_value(i);
		int opt_out;

		if (  !nsec3_rrset
		    || nsec3_rrset->rr_type != GETDNS_RRTYPE_NSEC3
		    ||!(rr = _getdns_rrtype_iter_init(&rr_spc, nsec3_rrset)))
			continue;

		if (!nsec3_covers_name(nsec3_rrset, ds_rrset->name, &opt_out))
			continue;

		if (nsec3_matches_name(nsec3_rrset, ds_rrset->name)) {
			bitmap = _getdns_rdf_iter_init_at( &bitmap_spc
			                                 , &rr->rr_i, 5);
			return  bitmap
			    &&  bitmap_has_type(bitmap, GETDNS_RRTYPE_NS)
			    && !bitmap_has_type(bitmap, GETDNS_RRTYPE_DS);
		}
		else if (opt_out)
			return 1;
	}
	return 0;
}

static void val_chain_node_cb(getdns_dns_req *dnsreq)
{
	chain_node *node = (chain_node *)dnsreq->user_pointer;
	getdns_network_req *netreq = dnsreq->netreqs[0];
	_getdns_rrset_iter *i, i_spc;
	_getdns_rrset *rrset;
	_getdns_rrsig_iter  *rrsig, rrsig_spc;
	size_t n_signers;

	switch (netreq->request_type) {
	case GETDNS_RRTYPE_DS    : node->ds.pkt     = netreq->response;
	                           node->ds.pkt_len = netreq->response_len;
	                           break;
	case GETDNS_RRTYPE_DNSKEY: node->dnskey.pkt     = netreq->response;
	                           node->dnskey.pkt_len = netreq->response_len;
		                   /* fallthrough */
	default                  : check_chain_complete(node->chains);
				   return;
	}
	node->lock++;
	n_signers = 0;
	for ( i = _getdns_rrset_iter_init(&i_spc, netreq->response
	                                        , netreq->response_len
	                                        , SECTION_NO_ADDITIONAL)
	    ; i
	    ; i = _getdns_rrset_iter_next(i)) {

		rrset = _getdns_rrset_iter_value(i);

		if (rrset->rr_type != GETDNS_RRTYPE_DS     &&
		    rrset->rr_type != GETDNS_RRTYPE_NSEC   &&
		    rrset->rr_type != GETDNS_RRTYPE_NSEC3)
			continue;

		for ( rrsig = _getdns_rrsig_iter_init(&rrsig_spc, rrset)
		    ; rrsig; rrsig = _getdns_rrsig_iter_next(rrsig)) {

			val_chain_sched_signer_node(node, rrsig);
			n_signers++;
		}
	}
	if (netreq->request_type != GETDNS_RRTYPE_DS)
		; /* pass */
	else if (n_signers) {
		_getdns_rrtype_iter ds_spc;

		if (_getdns_rrtype_iter_init(&ds_spc, &node->ds))
			; /* pass */

		else if (insecure_delegation(&node->ds)) {
			debug_sec_print_rrset("Insecure delegation. "
			    "Canceling requests below ", &node->ds);
			cancel_requests_for_subdomains_of(
			    node->chains, node->ds.name);
		} else {
			debug_sec_print_rrset("No DS at ", &node->ds);
		}
	} else {
		/* No signed DS and no signed proof of non-existance.
		 * Search further up the tree...
		 */
		val_chain_sched_ds_node(node->parent);
	}
	if (node->lock) node->lock--;
	check_chain_complete(node->chains);
}


/***************************  DNSSEC Validation  *****************************
 *****************************************************************************/


/* Returns whether a key in set dnskey is used to sign rrset.
 * Only keytag and signer name is compared.  The signature is not verified.
 */
static int key_matches_signer(_getdns_rrset *dnskey, _getdns_rrset *rrset)
{
	_getdns_rrtype_iter rr_spc, *rr;
	_getdns_rrsig_iter rrsig_spc, *rrsig;
	uint16_t keytag;
	_getdns_rdf_iter rdf_spc, *rdf;
	uint8_t signer_spc[256];
	const uint8_t *signer;
	size_t signer_len = sizeof(signer_spc);

	assert(dnskey->rr_type == GETDNS_RRTYPE_DNSKEY);


	for ( rr = _getdns_rrtype_iter_init(&rr_spc, dnskey)
	    ; rr ; rr = _getdns_rrtype_iter_next(rr) ) {


		/* Enough space to at least read algorithm field? */
		if (rr->rr_i.nxt < rr->rr_i.rr_type + 14)
			continue;

		/* Then we have at least 4 bytes to calculate keytag */
		keytag = gldns_calc_keytag_raw(
		    (UNCONST_UINT8_p)rr->rr_i.rr_type + 10,
		    rr->rr_i.nxt - rr->rr_i.rr_type - 10);

		for ( rrsig = _getdns_rrsig_iter_init(&rrsig_spc, rrset)
		    ; rrsig ; rrsig = _getdns_rrsig_iter_next(rrsig) ) {

			if (/* Space for keytag & signer in rrsig rdata? */
			       rrsig->rr_i.nxt >= rrsig->rr_i.rr_type + 28

			    /* Does Algorithm match */
			    && rrsig->rr_i.rr_type[12] == rr->rr_i.rr_type[13]

			    /* Does the keytag match? */
			    && gldns_read_uint16(rrsig->rr_i.rr_type + 26)
					    == keytag

			    /* Does the signer name match? */
			    && (rdf = _getdns_rdf_iter_init_at(
					    &rdf_spc, &rrsig->rr_i, 7))

			    && (signer = _getdns_rdf_if_or_as_decompressed(
					    rdf, signer_spc, &signer_len))

			    && _dname_equal(dnskey->name, signer))

				return keytag;
		}
	}
	return 0;
}

static size_t _rr_uncompressed_rdata_size(_getdns_rrtype_iter *rr)
{
	_getdns_rdf_iter *rdf, rdf_spc;
	uint8_t decompressed[256];
	size_t sz = 0, decompressed_sz;

	for ( rdf = _getdns_rdf_iter_init(&rdf_spc, &rr->rr_i)
	    ; rdf
	    ; rdf = _getdns_rdf_iter_next(rdf)) {

		if ((rdf->rdd_pos->type & GETDNS_RDF_N_C) == GETDNS_RDF_N_C) {
			decompressed_sz = sizeof(decompressed);
			if (_getdns_rdf_if_or_as_decompressed(
			    rdf, decompressed, &decompressed_sz))
				sz += decompressed_sz;
		} else
			sz += rdf->nxt - rdf->pos;
	}
	return sz;
}

static size_t _rr_rdata_size(_getdns_rrtype_iter *rr)
{
	const _getdns_rr_def *rr_def;
	size_t i;

	rr_def = _getdns_rr_def_lookup(gldns_read_uint16(rr->rr_i.rr_type));

	for (i = 0; i < rr_def->n_rdata_fields; i++)
		if ((rr_def->rdata[i].type & GETDNS_RDF_N_C) == GETDNS_RDF_N_C)
			return _rr_uncompressed_rdata_size(rr);

	/* assert(gldns_read_uint16(rr->rr_type+8) == rr->nxt-rr->rr_type-10);
	 */
	return rr->rr_i.nxt - rr->rr_i.rr_type - 10;
}

/* Iterate byte by byte over rdata canonicalizing dname's */
typedef struct canon_rdata_iter {
	_getdns_rdf_iter  rdf_spc;
	_getdns_rdf_iter *rdf;
	uint8_t           cdname[256]; /* Canonical dname */
	const uint8_t    *pos;
	size_t            len;
} canon_rdata_iter;

static inline void canon_rdata_iter_field_init(canon_rdata_iter *i)
{
	for (;;) {
		if ((i->rdf->rdd_pos->type & GETDNS_RDF_N) == GETDNS_RDF_N) {
			i->len = sizeof(i->cdname);
			if ((i->pos = _getdns_rdf_if_or_as_decompressed(
			    i->rdf, i->cdname, &i->len))) {
				_dname_canonicalize(i->pos, i->cdname);
				i->pos = i->cdname;
			}
		} else {
			i->pos = i->rdf->pos;
			i->len = i->rdf->nxt - i->rdf->pos;
		}
		if (i->len || !(i->rdf = _getdns_rdf_iter_next(i->rdf)))
			return;
	}
}

static inline void canon_rdata_iter_init(canon_rdata_iter*i,_getdns_rr_iter*rr)
{
	if ((i->rdf = _getdns_rdf_iter_init(&i->rdf_spc, rr)))
		canon_rdata_iter_field_init(i);
}

static inline int canon_rdata_iter_data(canon_rdata_iter *i)
{
	return i->rdf != NULL;
}

static inline uint8_t canon_rdata_iter_byte(canon_rdata_iter *i)
{
	return *i->pos;
}

static inline void canon_rdata_iter_next(canon_rdata_iter *i)
{
	if (--i->len == 0 && (i->rdf = _getdns_rdf_iter_next(i->rdf)))
		canon_rdata_iter_field_init(i);
	else
		i->pos++;
}

static int _rr_iter_rdata_cmp(const void *a, const void *b)
{
	_getdns_rr_iter *x = (_getdns_rr_iter *)a;
	_getdns_rr_iter *y = (_getdns_rr_iter *)b;

	uint16_t rr_type = gldns_read_uint16(x->rr_type);
	size_t x_rdata_len, y_rdata_len;
	int r;

	canon_rdata_iter p, q;

	assert(rr_type == gldns_read_uint16(y->rr_type));

	if (!_dnssec_rdata_to_canonicalize(rr_type)) {
		/* Memory compare of rdata */
		x_rdata_len = x->nxt - x->rr_type - 10;
		y_rdata_len = y->nxt - y->rr_type - 10;
		if ((r = memcmp(x->rr_type + 10, y->rr_type + 10,
		    x_rdata_len < y_rdata_len ? x_rdata_len : y_rdata_len)))
			return r;
		return x_rdata_len < y_rdata_len ? -1 :
		       x_rdata_len > y_rdata_len ?  1 : 0;
	}
	for ( canon_rdata_iter_init(&p, x), canon_rdata_iter_init(&q, y)
	    ; canon_rdata_iter_data(&p)  && canon_rdata_iter_data(&q)
	    ; canon_rdata_iter_next(&p)   , canon_rdata_iter_next(&q) ) {

		if (canon_rdata_iter_byte(&p) != canon_rdata_iter_byte(&q))
			return canon_rdata_iter_byte(&p) >
			       canon_rdata_iter_byte(&q) ? 1 : -1;
	}
	return canon_rdata_iter_data(&p) ?  1
	     : canon_rdata_iter_data(&q) ? -1 : 0;
}

/* Verifies the signature rrsig for rrset rrset with key key.
 * When the rrset was a wildcard expansion (rrsig labels < labels owner name),
 * nc_name will be set to the next closer (within rrset->name).
 */
#define VAL_RRSET_SPC_SZ 256
static int _getdns_verify_rrsig(const struct mem_funcs *mf,
    _getdns_rrset *rrset, _getdns_rrsig_iter *rrsig, _getdns_rrtype_iter *key,
    const uint8_t **nc_name)
{
	int r;
	int to_skip;
	_getdns_rr_iter  val_rrset_spc[VAL_RRSET_SPC_SZ];
	_getdns_rr_iter *val_rrset = val_rrset_spc;
	_getdns_rrtype_iter rr_spc, *rr;
	size_t n_rrs, i, valbuf_sz, owner_len;
	_getdns_rdf_iter *signer, signer_spc, *rdf, rdf_spc;
	uint8_t valbuf_spc[4096], *valbuf_buf = valbuf_spc;
	uint8_t cdname_spc[256], owner[256];
	const uint8_t *cdname, *owner_offset;
	size_t cdname_len, pos;
	uint32_t orig_ttl;
	gldns_buffer valbuf;
	char *reason;

	/* nc_name should already have been initialized by the parent! */
	assert(nc_name);
	assert(!*nc_name);

	if (!(signer = _getdns_rdf_iter_init_at(&signer_spc, &rrsig->rr_i, 7)))
		return 0;
	valbuf_sz = signer->nxt - rrsig->rr_i.rr_type - 10;

	/* We were able to get the signer,
	 * so the labels rdata field is definitely readable
	 */
	assert(rrsig->rr_i.rr_type + 14 <= rrsig->rr_i.nxt);

	/* If the number of labels in the owner is larger than  "labels" rdata
	 * field, then this is a wildcard expansion.
	 */
	if (_dname_label_count(rrset->name) > (size_t)rrsig->rr_i.rr_type[13]) {

		/* This is a valid wildcard expansion.  Calculate and return the
		 * "Next closer" name, because we need another NSEC to cover it.
		 * (except for rrsigs for NSECs, but those are dealt with later)
		 */
		to_skip = (int)_dname_label_count(rrset->name)
			- (int)rrsig->rr_i.rr_type[13];

		for ( owner_offset = rrset->name
		    ; to_skip > 0
		    ; owner_offset += *owner_offset + 1, to_skip--);

		if ((owner_len = _dname_len(owner_offset) + 2) > 255)
			return 0;

		owner[0] = 1; owner[1] = '*';
		(void) memcpy(owner + 2, owner_offset, owner_len - 2);

	} else if ((owner_len = _dname_len(rrset->name)) > 255)
		return 0;
	else
		(void) memcpy(owner, rrset->name, owner_len);

	_dname_canonicalize2(owner);

	for (;;) {
		for ( rr = _getdns_rrtype_iter_init(&rr_spc, rrset), n_rrs = 0
		    ; rr
		    ; rr = _getdns_rrtype_iter_next(rr), n_rrs++) {

			if (val_rrset == val_rrset_spc) {
				valbuf_sz += owner_len
				          +  2 /* type */
				          +  2 /* class */
				          +  4 /* Orig TTL */
					  +  2 /* Rdata len */
				          +  _rr_rdata_size(rr);
				if (n_rrs < VAL_RRSET_SPC_SZ)
					val_rrset[n_rrs] = rr->rr_i;
			} else
				val_rrset[n_rrs] = rr->rr_i;
		}
		/* Did everything fit? Then break */
		if (val_rrset != val_rrset_spc || n_rrs <= VAL_RRSET_SPC_SZ)
			break;

		/* More space needed for val_rrset */
		val_rrset = GETDNS_XMALLOC(*mf, _getdns_rr_iter, n_rrs);
	}
	DEBUG_SEC( "sizes: %"PRIsz" rrs, %"PRIsz" bytes for validation buffer\n"
	         , n_rrs, valbuf_sz);

	qsort(val_rrset, n_rrs, sizeof(_getdns_rr_iter), _rr_iter_rdata_cmp);

	if (valbuf_sz >= sizeof(valbuf_spc))
		valbuf_buf = GETDNS_XMALLOC(*mf, uint8_t, valbuf_sz);

	gldns_buffer_init_frm_data(&valbuf, valbuf_buf, valbuf_sz);
	gldns_buffer_write(&valbuf,
	    rrsig->rr_i.rr_type + 10, signer->nxt - rrsig->rr_i.rr_type - 10);
	_dname_canonicalize2(gldns_buffer_at(&valbuf, 18));

	orig_ttl = gldns_read_uint32(rrsig->rr_i.rr_type + 14);

	if (!_dnssec_rdata_to_canonicalize(rrset->rr_type))
		for (i = 0; i < n_rrs; i++) {
			/* Get rid of doubles */
			if (i && !_rr_iter_rdata_cmp(
			    &val_rrset[i], &val_rrset[i-1]))
				continue;

			gldns_buffer_write(&valbuf, owner, owner_len);
			gldns_buffer_write_u16(&valbuf, rrset->rr_type);
			gldns_buffer_write_u16(&valbuf, rrset->rr_class);
			gldns_buffer_write_u32(&valbuf, orig_ttl);
			gldns_buffer_write(&valbuf, val_rrset[i].rr_type + 8,
			    val_rrset[i].nxt - val_rrset[i].rr_type - 8);
		}
	else for (i = 0; i < n_rrs; i++) {
		if (i && !_rr_iter_rdata_cmp(&val_rrset[i], &val_rrset[i-1]))
			continue;
		gldns_buffer_write(&valbuf, owner, owner_len);
		gldns_buffer_write_u16(&valbuf, rrset->rr_type);
		gldns_buffer_write_u16(&valbuf, rrset->rr_class);
		gldns_buffer_write_u32(&valbuf, orig_ttl);
		pos = gldns_buffer_position(&valbuf);
		gldns_buffer_skip(&valbuf, 2);
		for ( rdf = _getdns_rdf_iter_init(&rdf_spc, &val_rrset[i])
		    ; rdf
		    ; rdf = _getdns_rdf_iter_next(rdf) ) {
			if (!(rdf->rdd_pos->type & GETDNS_RDF_N)) {
				gldns_buffer_write(
				    &valbuf, rdf->pos, rdf->nxt - rdf->pos);
				continue;
			}
			cdname_len = sizeof(cdname);
			if (!(cdname = _getdns_rdf_if_or_as_decompressed(
			    rdf, cdname_spc, &cdname_len)))
				continue;
			gldns_buffer_write(&valbuf, cdname, cdname_len);
			_dname_canonicalize2(
			    gldns_buffer_current(&valbuf) - cdname_len);
		}
		gldns_buffer_write_u16_at(&valbuf, pos,
		    (uint16_t)(gldns_buffer_position(&valbuf) - pos - 2));
	}
	DEBUG_SEC( "written to valbuf: %"PRIsz" bytes\n"
	         , gldns_buffer_position(&valbuf));
	assert(gldns_buffer_position(&valbuf) <= valbuf_sz);

	gldns_buffer_flip(&valbuf);
	r = _getdns_verify_canonrrset(&valbuf, key->rr_i.rr_type[13],
	    (UNCONST_UINT8_p)signer->nxt, rrsig->rr_i.nxt - signer->nxt,
	    (UNCONST_UINT8_p)key->rr_i.rr_type+14,
	    key->rr_i.nxt - key->rr_i.rr_type-14,
	    &reason);

#if defined(SEC_DEBUG) && SEC_DEBUG
	if (r == 0) {
		DEBUG_SEC("verification failed: %s\n", reason);
		debug_sec_print_dname("verification failed for: ", owner);
		debug_sec_print_rrset("verification failed for rrset: ", rrset);
		debug_sec_print_rr("verification failed sig: ", &rrsig->rr_i);
		debug_sec_print_rr("verification failed key: ", &key->rr_i);
	}
#endif
	if (val_rrset != val_rrset_spc)
		GETDNS_FREE(*mf, val_rrset);
	if (valbuf_buf != valbuf_spc)
		GETDNS_FREE(*mf, valbuf_buf);
	if (!r)
		return 0;

	/* Verification has already been done, so the labels rdata field is
	 * definitely readable
	 */
	assert(rrsig->rr_i.rr_type + 14 <= rrsig->rr_i.nxt);

	/* If the number of labels in the owner name mathes the "labels" rdata
	 * field, then this was not a wildcard expansion, and everything is
	 * good.
	 */
	if ((size_t)rrsig->rr_i.rr_type[13] == _dname_label_count(rrset->name))
		return 1;

	/* This is a valid wildcard expansion.  Calculate and return the
	 * "Next closer" name, because we need another NSEC to cover it.
	 * (except for rrsigs for NSECs, but those are dealt with later)
	 */
	to_skip = (int)_dname_label_count(rrset->name)
		- (int)rrsig->rr_i.rr_type[13] - 1;

	for ( *nc_name = rrset->name
	    ; to_skip > 0
	    ; *nc_name += **nc_name + 1, to_skip--);

	return 1;
}

/* Calculates NSEC3 hash for name, and stores that into label */
static uint8_t *_getdns_nsec3_hash_label(uint8_t *label, size_t label_len,
    const uint8_t *name, uint8_t algorithm,
    uint16_t iterations, const uint8_t *salt)
{
	uint8_t buf[512], *dst, *eob;
	const uint8_t *src;
	uint8_t md[SHA_DIGEST_LENGTH + 256];

	assert(SHA_DIGEST_LENGTH + 256 < sizeof(buf));

	if (algorithm != GLDNS_SHA1)
		return NULL;

	for ( src = name, dst = buf, eob = buf + sizeof(buf)
	    ; *src && dst + *src < eob
	    ;  src += *src + 1, dst += *dst + 1 )
		_dname_label_copy(dst, src, eob - dst);

	if (*src || dst + *salt >= eob)
		return NULL;
	*dst++ = 0;
	(void)memcpy(dst, salt + 1, *salt);
	dst += *salt;

	_getdns_tls_sha1(buf, dst - buf, md);
	if (iterations) {
		(void)memcpy(buf + SHA_DIGEST_LENGTH, salt + 1, *salt);
		while (iterations--) {
			(void)memcpy(buf, md, SHA_DIGEST_LENGTH);
			_getdns_tls_sha1(buf, SHA_DIGEST_LENGTH + *salt, md);
		}
	}
	*label = gldns_b32_ntop_extended_hex(
	    md, SHA_DIGEST_LENGTH, (char *)label + 1, label_len - 1);

	return label;
}

static uint8_t *name2nsec3_label(
    _getdns_rrset *nsec3, const uint8_t *name, uint8_t *label, size_t label_len)
{
	_getdns_rrsig_iter rrsig_spc, *rrsig;
	_getdns_rdf_iter rdf_spc, *rdf;
	uint8_t signer_spc[256];
	const uint8_t *signer;
	size_t signer_len = sizeof(signer_spc);
	_getdns_rrtype_iter rr_spc, *rr;

	if (/* With the "first" signature */
	       (rrsig = _getdns_rrsig_iter_init(&rrsig_spc, nsec3))

	    /* Access the signer name rdata field (7th) */
	    && (rdf = _getdns_rdf_iter_init_at(
			    &rdf_spc, &rrsig->rr_i, 7))

	    /* Verify & decompress */
	    && (signer = _getdns_rdf_if_or_as_decompressed(
			    rdf, signer_spc, &signer_len))

	    /* signer of the NSEC3 is direct parent for this NSEC3? */
	    && _dname_equal(
		    signer, nsec3->name + *nsec3->name + 1)

	    /* signer of the NSEC3 is parent of name? */
	    && _dname_is_parent(signer, name)

	    /* Initialize rr for getting NSEC3 rdata fields */
	    && (rr = _getdns_rrtype_iter_init(&rr_spc, nsec3))

	    /* Check for available space to get rdata fields */
	    && rr->rr_i.rr_type + 15 <= rr->rr_i.nxt
	    && rr->rr_i.rr_type + 14 + rr->rr_i.rr_type[14] <= rr->rr_i.nxt)

		/* Get the hashed label */
		return _getdns_nsec3_hash_label(label, label_len, name,
			    rr->rr_i.rr_type[10],
			    gldns_read_uint16(rr->rr_i.rr_type + 12),
			    rr->rr_i.rr_type + 14);
	return NULL;
}


static int nsec3_iteration_count_high(_getdns_rrtype_iter *dnskey, _getdns_rrset *nsec3)
{
	_getdns_rrtype_iter rr_spc, *rr;
	size_t bits;

	/* No NSEC3, then iteration count is not too high */
	if (nsec3->rr_type != GETDNS_RRTYPE_NSEC3)
		return 0;

	/* Enough space to at least read algorithm field?
	 * Without key data iteration count is definitely too high.
	 */
	if (dnskey->rr_i.nxt < dnskey->rr_i.rr_type + 14)
		return 1;

	if (/* Initialize rr for getting NSEC3 rdata fields */
	      !(rr = _getdns_rrtype_iter_init(&rr_spc, nsec3))

	    /* Check for available space to get rdata fields */
	    || rr->rr_i.rr_type + 14 > rr->rr_i.nxt)
		return 1;

	bits = gldns_rr_dnskey_key_size_raw(dnskey->rr_i.rr_type + 10,
	    dnskey->rr_i.nxt - dnskey->rr_i.rr_type - 10,
	    dnskey->rr_i.rr_type[13]);

	if (bits > 2048)
		return gldns_read_uint16(rr->rr_i.rr_type + 12) > 2500;
	else if (bits > 1024)
		return gldns_read_uint16(rr->rr_i.rr_type + 12) > 500;
	else
		return gldns_read_uint16(rr->rr_i.rr_type + 12) > 150;
}

static int check_dates(time_t now, int32_t skew, int32_t exp, int32_t inc)
{
	return (exp - inc > 0) && (inc - now < skew) && (now - exp < skew);
}

/* Returns whether dnskey signed rrset.  If the rrset was a valid wildcard
 * expansion, nc_name will point to the next closer part of the name in rrset.
 */
static int dnskey_signed_rrset(const struct mem_funcs *mf, time_t now,
    uint32_t skew, _getdns_rrtype_iter *dnskey, _getdns_rrset *rrset,
    const uint8_t **nc_name)
{
	_getdns_rrsig_iter rrsig_spc, *rrsig;
	_getdns_rdf_iter rdf_spc, *rdf;
	uint8_t signer_spc[256];
	const uint8_t *signer;
	size_t signer_len = sizeof(signer_spc);
	uint16_t keytag;

	assert(dnskey->rrset->rr_type == GETDNS_RRTYPE_DNSKEY);
	assert(nc_name);

	*nc_name = NULL;

	/* Enough space to at least read algorithm field? */
	if (dnskey->rr_i.nxt < dnskey->rr_i.rr_type + 14)
		return 0;

	/* Then we have at least 4 bytes to calculate keytag */
	keytag = gldns_calc_keytag_raw((UNCONST_UINT8_p)dnskey->rr_i.rr_type + 10,
			dnskey->rr_i.nxt - dnskey->rr_i.rr_type - 10);

	for ( rrsig = _getdns_rrsig_iter_init(&rrsig_spc, rrset)
	    ; rrsig ; rrsig = _getdns_rrsig_iter_next(rrsig) ) {

		if (/* Space for keytag & signer in rrsig rdata? */
		        rrsig->rr_i.nxt >= rrsig->rr_i.rr_type + 28

		    /* Does Algorithm match */
		    && rrsig->rr_i.rr_type[12] == dnskey->rr_i.rr_type[13]

		    /* Does the keytag match? */
		    && gldns_read_uint16(rrsig->rr_i.rr_type + 26) == keytag

		    /* Signature still (or already) valid? */
		    && check_dates(now, skew,
			    gldns_read_uint32(rrsig->rr_i.rr_type + 18),
			    gldns_read_uint32(rrsig->rr_i.rr_type + 22))

		    /* Does the signer name match? */
		    && (rdf = _getdns_rdf_iter_init_at(
				    &rdf_spc, &rrsig->rr_i, 7))

		    && (signer = _getdns_rdf_if_or_as_decompressed(
				    rdf, signer_spc, &signer_len))

		    && _dname_equal(dnskey->rrset->name, signer)

		    /* Does the signature verify? */
		    && _getdns_verify_rrsig(mf, rrset,rrsig,dnskey,nc_name)) {

			debug_sec_print_rr("key ", &dnskey->rr_i);
			debug_sec_print_rrset("signed ", rrset);

			/* Signal insecurity by too high nsec3 iteration
			 * count with NSEC3_ITERATION_COUNT_HIGH
			 * bit in return value.
			 */
			return ( nsec3_iteration_count_high(dnskey, rrset)
			       ? NSEC3_ITERATION_COUNT_HIGH
			       : SIGNATURE_VERIFIED
			       ) | keytag;
		}
	}
	return 0;
}

/* Returns whether a dnskey for keyset signed a non wildcard rrset. */
static int a_key_signed_rrset_no_wc(const struct mem_funcs *mf, time_t now,
    uint32_t skew, _getdns_rrset *keyset, _getdns_rrset *rrset)
{
	_getdns_rrtype_iter dnskey_spc, *dnskey;
	const uint8_t *nc_name; /* Initialized by dnskey_signed_rrset() */
	int keytag;

	assert(keyset->rr_type == GETDNS_RRTYPE_DNSKEY);

	for ( dnskey = _getdns_rrtype_iter_init(&dnskey_spc, keyset)
	    ; dnskey ; dnskey = _getdns_rrtype_iter_next(dnskey) ) {

		if (!(keytag = dnskey_signed_rrset(mf, now, skew,
		    dnskey, rrset, &nc_name)))
			continue;

		if (!nc_name) /* Not a wildcard, then success! */
			return keytag;

 		/* Not a wildcard expansion, but the wildcard name itself. */
		if (rrset->rr_type == GETDNS_RRTYPE_NSEC &&
		    rrset->name[0] == 1 && rrset->name[1] == '*' &&
		    nc_name == rrset->name)
			return keytag;
	}
	return 0;
}

static int find_nsec_covering_name(const struct mem_funcs *mf,
    time_t now, uint32_t skew, _getdns_rrset *dnskey,
    _getdns_rrset *rrset, const uint8_t *name, int *opt_out);

/* Returns whether a dnskey for keyset signed rrset. */
static int a_key_signed_rrset(const struct mem_funcs *mf, time_t now,
    uint32_t skew, _getdns_rrset *keyset, _getdns_rrset *rrset)
{
	_getdns_rrtype_iter dnskey_spc, *dnskey;
	const uint8_t *nc_name; /* Initialized by dnskey_signed_rrset() */

	int keytag;

	assert(keyset->rr_type == GETDNS_RRTYPE_DNSKEY);

	for ( dnskey = _getdns_rrtype_iter_init(&dnskey_spc, keyset)
	    ; dnskey ; dnskey = _getdns_rrtype_iter_next(dnskey) ) {

		if (!(keytag = dnskey_signed_rrset(mf, now, skew,
		    dnskey, rrset, &nc_name)))
			continue;

		if (!nc_name) /* Not a wildcard, then success! */
			return keytag;

		/* Wildcard RRSIG for a NSEC on the wildcard.
		 * There is no more specific!
		 */
		if (rrset->rr_type == GETDNS_RRTYPE_NSEC &&
		    rrset->name[0] == 1 && rrset->name[1] == '*' &&
		    nc_name == rrset->name)
			return keytag;

		debug_sec_print_rrset("wildcard expanded to: ", rrset);
		debug_sec_print_dname("Find NSEC covering the more sepecific: "
				, nc_name);

		if (find_nsec_covering_name(
		    mf, now, skew, keyset, rrset, nc_name, NULL))
			return keytag;
	}
	return 0;
}

/* Returns whether a DS in ds_set matches a dnskey in dnskey_set which in turn
 * signed the dnskey set.
 */
static int ds_authenticates_keys(const struct mem_funcs *mf,
    time_t now, uint32_t skew, _getdns_rrset *ds_set, _getdns_rrset *dnskey_set)
{
	_getdns_rrtype_iter dnskey_spc, *dnskey;
	_getdns_rrtype_iter ds_spc, *ds;
	uint16_t keytag;
	const uint8_t *nc_name; /* Initialized by dnskey_signed_rrset() */
	size_t valid_dsses = 0, supported_dsses = 0;
	uint8_t max_supported_digest = 0;
	int max_supported_result = 0;
	unsigned char digest_spc[256], *digest;
	unsigned char digest_buf_spc[2048], *digest_buf;
	size_t digest_len, digest_buf_len, dnskey_owner_len;

	assert(ds_set->rr_type == GETDNS_RRTYPE_DS);
	assert(dnskey_set->rr_type == GETDNS_RRTYPE_DNSKEY);

	/* The ds_set is already authenticated! */

	if (!_dname_equal(ds_set->name, dnskey_set->name))
		return 0;

	debug_sec_print_rrset("ds_authenticates_keys DS: ", ds_set);
	debug_sec_print_rrset("ds_authenticates_keys DNSKEY: ", dnskey_set);

	if ((dnskey_owner_len = _dname_len(dnskey_set->name)) >= 255)
		return 0;

	(void) memcpy(digest_buf_spc, dnskey_set->name, dnskey_owner_len);
	_dname_canonicalize2(digest_buf_spc);

	for ( dnskey = _getdns_rrtype_iter_init(&dnskey_spc, dnskey_set)
	    ; dnskey ; dnskey = _getdns_rrtype_iter_next(dnskey)) {

		/* Enough space to at least read algorithm field? */
		if (dnskey->rr_i.nxt < dnskey->rr_i.rr_type + 14)
			continue;

		keytag = gldns_calc_keytag_raw(
		    (UNCONST_UINT8_p) dnskey->rr_i.rr_type + 10,
		    dnskey->rr_i.nxt - dnskey->rr_i.rr_type - 10);

		for ( ds = _getdns_rrtype_iter_init(&ds_spc, ds_set)
		    ; ds ; ds = _getdns_rrtype_iter_next(ds)) {

			if (/* Space for keytag, algorithm & digest type? */
			       ds->rr_i.nxt < ds->rr_i.rr_type + 14

			    /* Does algorithm match? */
			    || ds->rr_i.rr_type[12] != dnskey->rr_i.rr_type[13]

			    /* Does the keytag match? */
			    || gldns_read_uint16(ds->rr_i.rr_type+10)!=keytag)

				continue;

			valid_dsses++;

			if (/* Algorithm is not RSAMD5 (deprecated) */
			       ds->rr_i.rr_type[12] == GLDNS_RSAMD5

			    /* Algorithm is supported */
			    || !_getdns_dnskey_algo_id_is_supported(
				    ds->rr_i.rr_type[12])

			    /* Digest is supported */
			    || !(digest_len = _getdns_ds_digest_size_supported(
				    ds->rr_i.rr_type[13])))

				continue;

			digest = digest_len <= sizeof(digest_spc) ? digest_spc
			    : GETDNS_XMALLOC(*mf, unsigned char, digest_len);

			digest_buf_len = dnskey->rr_i.nxt
			               - dnskey->rr_i.rr_type - 10
			               + dnskey_owner_len;
			digest_buf = digest_buf_len <= sizeof(digest_buf_spc)
			    ? digest_buf_spc
			    : GETDNS_XMALLOC(*mf, unsigned char, digest_buf_len);

			if (digest_buf != digest_buf_spc)
				(void) memcpy(digest_buf,
				    digest_buf_spc, dnskey_owner_len);

			(void) memcpy(digest_buf + dnskey_owner_len,
			    dnskey->rr_i.rr_type + 10,
			    dnskey->rr_i.nxt - dnskey->rr_i.rr_type - 10);

			if (!_getdns_secalgo_ds_digest(ds->rr_i.rr_type[13],
			    digest_buf, digest_buf_len, digest)) {

				if (digest != digest_spc)
					GETDNS_FREE(*mf, digest);
				if (digest_buf != digest_buf_spc)
					GETDNS_FREE(*mf, digest_buf);
				continue;
			}
			supported_dsses++;

			/* The result of the best digest type counts!
			 * We'll assume higher is better for now.
			 * So, continue with next DS if...
			 */
			if (/* we already had a better digest earlier */
			       ds->rr_i.rr_type[13] < max_supported_digest

			    /* or we had the same digest and it already gave
			     * a match  (to a key in dnskey_set which
			     *           authenticated the dnskey_set).
			     */
			    || (   ds->rr_i.rr_type[13] == max_supported_digest
				&& max_supported_result)) {
				if (digest != digest_spc)
					GETDNS_FREE(*mf, digest);
				if (digest_buf != digest_buf_spc)
					GETDNS_FREE(*mf, digest_buf);

				DEBUG_SEC("Better DS available\n");
				continue;
			}
			max_supported_digest = ds->rr_i.rr_type[13];
			max_supported_result = 0;

			if ((int)digest_len != ds->rr_i.nxt - ds->rr_i.rr_type-14
			    || memcmp(digest, ds->rr_i.rr_type+14, digest_len) != 0) {
				if (digest != digest_spc)
					GETDNS_FREE(*mf, digest);
				if (digest_buf != digest_buf_spc)
					GETDNS_FREE(*mf, digest_buf);

				DEBUG_SEC("HASH length mismatch %"PRIsz" != %"PRIsz"\n",
					digest_len, ds->rr_i.nxt - ds->rr_i.rr_type-14);
				continue;
			}
			/* Match! */
			if (digest != digest_spc)
				GETDNS_FREE(*mf, digest);
			if (digest_buf != digest_buf_spc)
				GETDNS_FREE(*mf, digest_buf);

			if (!dnskey_signed_rrset(mf, now, skew,
			    dnskey, dnskey_set, &nc_name)
			    || nc_name /* No DNSKEY's on wildcards! */) {

				debug_sec_print_rrset("keyset did not "
				    "authenticate: ", dnskey_set);
				continue;
			}
			debug_sec_print_rrset(
			    "keyset authenticated: ", dnskey_set);
			max_supported_result = SIGNATURE_VERIFIED | keytag;
		}
	}
	DEBUG_SEC("valid_dsses: %"PRIsz", supported_dsses: %"PRIsz"\n",
			valid_dsses, supported_dsses);
	if (valid_dsses && !supported_dsses)
		return NO_SUPPORTED_ALGORITHMS;
	else
		return max_supported_result;
}

static int nsec_covers_name(
    _getdns_rrset *nsec, const uint8_t *name, const uint8_t **ce_name)
{
	uint8_t owner_spc[256], next_spc[256];
	const uint8_t *owner, *next;
	size_t owner_len = sizeof(owner_spc), next_len = sizeof(next_spc);

	_getdns_rrtype_iter rr_spc, *rr;
	_getdns_rdf_iter rdf_spc, *rdf;
	int nsec_cmp;
	const uint8_t *common1, *common2;

	if (/* Get owner and next, nicely decompressed */
	       !(rr = _getdns_rrtype_iter_init(&rr_spc, nsec))
	    || !(rdf = _getdns_rdf_iter_init(&rdf_spc, &rr->rr_i))
	    || !(owner = _getdns_owner_if_or_as_decompressed(
			    &rr->rr_i, owner_spc, &owner_len))
	    || !(next = _getdns_rdf_if_or_as_decompressed(
			    rdf, next_spc, &next_len)))
		return 0;

	debug_sec_print_dname("nsec owner: ", owner);
	debug_sec_print_dname("name      : ", name);
	debug_sec_print_dname("nsec next : ", next);

	if (ce_name) {
		common1 = dname_shared_parent(name, owner);
		common2 = dname_shared_parent(name, next);
		*ce_name = _dname_label_count(common1)
		         > _dname_label_count(common2) ? common1 : common2;
		debug_sec_print_dname("nsec closest encloser: ", *ce_name);
	}

	nsec_cmp = dname_compare(owner, next);
	if (nsec_cmp < 0) {
		/* Regular NSEC
		 * >= so it can match the wildcard
		 * (for wildcard NODATA proofs).
		 */
		return dname_compare(name, owner) >= 0
		    && dname_compare(name, next)  <  0;

	} else if (nsec_cmp > 0) {
		/* The wrap around nsec.  So NSEC->nxt == zone.name.
		 * qname must be a subdomain of that.
		 */
		return dname_compare(name, owner) >= 0
		    && _dname_is_parent(next, name) && dname_compare(next, name);

	} else {
		/* This nsec is the only nsec.
		 * zone.name NSEC zone.name, disproves everything else,
		 * but only for subdomains of that zone.
		 * (also no zone.name == qname of course)
		 */
		return _dname_is_parent(owner, name) && dname_compare(owner, name);
	}
}

static int nsec3_matches_name(_getdns_rrset *nsec3, const uint8_t *name)
{
	uint8_t label[64], owner[64];

	if (name2nsec3_label(nsec3, name, label, sizeof(label))
	    && _dname_label_copy(owner, nsec3->name, sizeof(owner)))

		return *nsec3->name == label[0] /* Labels same size? */
		    && memcmp(owner + 1, label + 1, label[0]) == 0;

	return 0;
}

static int nsec3_covers_name(
    _getdns_rrset *nsec3, const uint8_t *name, int *opt_out)
{
	uint8_t label[65], next[65], owner[65];
	_getdns_rrtype_iter rr_spc, *rr;
	_getdns_rdf_iter rdf_spc, *rdf;
	int nsz = 0, nsec_cmp;

	if (!name2nsec3_label(nsec3, name, label, sizeof(label)-1))
		return 0;

	label[label[0]+1] = 0;

	if (   !(rr = _getdns_rrtype_iter_init(&rr_spc, nsec3))
	    || !(rdf = _getdns_rdf_iter_init_at(&rdf_spc, &rr->rr_i, 4))
	    || rdf->pos + *rdf->pos + 1 > rdf->nxt
	    || (nsz = gldns_b32_ntop_extended_hex(rdf->pos + 1, *rdf->pos,
		    (char *)next + 1, sizeof(next)-2)) < 0
	    || *nsec3->name > sizeof(owner) - 2
	    || !_dname_label_copy(owner, nsec3->name, sizeof(owner)-1)) {

		DEBUG_SEC("Error getting NSEC3 owner & next labels\n");
		return 0;
	}
	owner[owner[0]+1] = 0;
	next[(next[0] = (uint8_t)nsz)+1] = 0;

	if (opt_out)
		*opt_out = (rr->rr_i.rr_type[11] & 1) != 0;

	debug_sec_print_dname("NSEC3 for: ", name);
	debug_sec_print_dname("       is: ", label);
	debug_sec_print_dname("inbetween: ", owner);
	debug_sec_print_dname("      and: ", next);

	nsec_cmp = dname_compare(owner, next);
	if (nsec_cmp >= 0) {
		/* The wrap around and apex-only nsec case */
		return dname_compare(label, owner) > 0
		    || dname_compare(label, next) < 0;
	} else {
		assert(nsec_cmp < 0);
		/* The normal case
		 * >= so it can match the wildcard
		 * (for wildcard NODATA proofs).
		 */
		return dname_compare(label, owner) >= 0
		    && dname_compare(label, next)  <  0;
	}
}

static int find_nsec_covering_name(const struct mem_funcs *mf, time_t now,
    uint32_t skew, _getdns_rrset *dnskey,
    _getdns_rrset *rrset, const uint8_t *name, int *opt_out)
{
	_getdns_rrset_iter i_spc, *i;
	_getdns_rrset *n;
	_getdns_rrtype_iter nsec_spc, *nsec_rr;
	_getdns_rdf_iter bitmap_spc, *bitmap;
	int keytag;

	if (opt_out)
		*opt_out = 0;

	for ( i = _getdns_rrset_iter_init(&i_spc, rrset->pkt, rrset->pkt_len
	                                        , SECTION_NO_ADDITIONAL)
	    ; i ; i = _getdns_rrset_iter_next(i)) {

		if ((n = _getdns_rrset_iter_value(i))
		    && n->rr_type == GETDNS_RRTYPE_NSEC3

		    /* Get the bitmap rdata field */
		    && (nsec_rr = _getdns_rrtype_iter_init(&nsec_spc, n))
		    && (bitmap = _getdns_rdf_iter_init_at(
				    &bitmap_spc, &nsec_rr->rr_i, 5))

		    && (keytag = a_key_signed_rrset_no_wc(
				    mf, now, skew, dnskey, n))
		    && (   keytag & NSEC3_ITERATION_COUNT_HIGH

		        || (   nsec3_covers_name(n, name, opt_out)
			    /* NSEC should cover, but not match name...
			     * Unless it is wildcard match, but then we have to
			     * check that rrset->rr_type is not enlisted,
			     * because otherwise it should have matched the
			     * wildcard.
			     *
			     * Also no CNAME... cause that should have matched too.
			     */

		            && (    !nsec3_matches_name(n, name)
		                || (   name[0] == 1 && name[1] == (uint8_t)'*'
		                    && !bitmap_has_type(bitmap, rrset->rr_type)
		                    && !bitmap_has_type(bitmap,
					    GETDNS_RRTYPE_CNAME)
		                   )
		               )
		           )
		       )
		    ) {

			debug_sec_print_rrset("NSEC3:   ", n);
			debug_sec_print_dname("covered: ", name);

			return keytag;
		}
		if ((n = _getdns_rrset_iter_value(i))
		    && n->rr_type == GETDNS_RRTYPE_NSEC
		    && nsec_covers_name(n, name, NULL)

		    /* Get the bitmap rdata field */
		    && (nsec_rr = _getdns_rrtype_iter_init(&nsec_spc, n))
		    && (bitmap = _getdns_rdf_iter_init_at(
				    &bitmap_spc, &nsec_rr->rr_i, 1))

		    /* NSEC should cover, but not match name...
		     * Unless it is wildcard match, but then we have to check
		     * that rrset->rr_type is not enlisted, because otherwise
		     * it should have matched the wildcard.
		     *
		     * Also no CNAME... cause that should have matched too.
		     */
		    && (    !_dname_equal(n->name, name)
		        || (   name[0] == 1 && name[1] == (uint8_t)'*'
		            && !bitmap_has_type(bitmap, rrset->rr_type)
		            && !bitmap_has_type(bitmap, GETDNS_RRTYPE_CNAME)
		           )
		       )

		    /* When qname is a subdomain of the NSEC owner, make
		     * sure there is no DNAME, and no delegation point
		     * there.
		     */
		    && (   !_dname_is_parent(n->name, name)
		        || (   !bitmap_has_type(bitmap, GETDNS_RRTYPE_DNAME)
		            && (   !bitmap_has_type(bitmap, GETDNS_RRTYPE_NS)
		                ||  bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA)
		               )
		           )
		       )

		    && (keytag = a_key_signed_rrset_no_wc(
					    mf, now, skew, dnskey, n))) {

			debug_sec_print_rrset("NSEC:   ", n);
			debug_sec_print_dname("covered: ", name);

			return keytag;
		}
	}
	return 0;
}

static int nsec3_find_next_closer(
    const struct mem_funcs *mf, time_t now, uint32_t skew,
    _getdns_rrset *dnskey, _getdns_rrset *rrset,
    const uint8_t *nc_name, int *opt_out)
{
	uint8_t wc_name[256] = { 1, (uint8_t)'*' };
	int my_opt_out, keytag;

	if (opt_out)
		*opt_out = 0;

	if (!(keytag = find_nsec_covering_name(
	    mf, now, skew, dnskey, rrset, nc_name, &my_opt_out))) {
		/* TODO: At least google doesn't return next_closer on wildcard
		 * nodata for DS query.  And in fact returns even bogus for,
		 * for example bladiebla.xavier.nlnet.nl DS.
		 */
		return 0;
	}
	if (opt_out)
		*opt_out = my_opt_out;

	/* Wild card not needed on a "covering" NODATA response,
	 * because of opt-out?
	 *
	 * We check for opt-out bit, because rcode is unreliable...
	 * ... the checked packet might be artificially constructed
	 * (if we came here via getdns_validate_dnssec) in which case
	 * rcode is always NOERROR.
	 */
	if (my_opt_out || keytag & NSEC3_ITERATION_COUNT_HIGH)
		return keytag;

	nc_name += *nc_name + 1;
	if (_dname_len(nc_name) > sizeof(wc_name) - 2)
		return 0;
	else
		(void) memcpy(wc_name + 2, nc_name, _dname_len(nc_name));

	return find_nsec_covering_name(
	    mf, now, skew, dnskey, rrset, wc_name, opt_out);
}

/*
 * Does a key from keyset dnskey prove the nonexistence of the (name, type)
 * tuple in rrset?
 *
 * On success returns the keytag + SIGNATURE_VERIFIED (0x10000) of the key
 * that signed the proof.
 * Or in case there were NSEC3's with too high iteration count for the
 * verifying key: it returns keytag + NSEC3_ITERATION_COUNT_HIGH (0x20000)
 */
static int key_proves_nonexistance(
    const struct mem_funcs *mf, time_t now, uint32_t skew,
    _getdns_rrset *keyset, _getdns_rrset *rrset, int *opt_out)
{
	_getdns_rrset nsec_rrset, *cover, *ce;
	_getdns_rrtype_iter nsec_spc, *nsec_rr;
	_getdns_rdf_iter bitmap_spc, *bitmap;
	_getdns_rrset_iter i_spc, *i;
	const uint8_t *ce_name, *nc_name;
	uint8_t wc_name[256] = { 1, (uint8_t)'*' };
	int keytag;

	assert(keyset->rr_type == GETDNS_RRTYPE_DNSKEY);

	debug_sec_print_rrset("Commencing NX proof for: ", rrset);
	if (opt_out)
		*opt_out = 0;

	/* The NSEC NODATA case
	 * ====================
	 * NSEC has same ownername as the rrset to deny.
	 * Only the rr_type is missing from the bitmap.
	 */
	nsec_rrset = *rrset;
	nsec_rrset.rr_type = GETDNS_RRTYPE_NSEC;
	nsec_rrset.sections = SECTION_NO_ADDITIONAL;

	if (/* A NSEC RR exists at the owner name of rrset */
	      (nsec_rr = _getdns_rrtype_iter_init(&nsec_spc, &nsec_rrset))

	    /* Get the bitmap rdata field */
	    && (bitmap = _getdns_rdf_iter_init_at(
			    &bitmap_spc, &nsec_rr->rr_i, 1))

	    /* At least the rr_type of rrset should be missing from it */
	    && !bitmap_has_type(bitmap, rrset->rr_type)

	    /* If the name is a CNAME, then we should have gotten the CNAME,
	     * So no CNAME bit either.
	     */
	    && !bitmap_has_type(bitmap, GETDNS_RRTYPE_CNAME)

	    /* In case of a DS query, make sure we have the parent side NSEC
	     * and not the child (so no SOA).
	     * Except for the root that is checked by itself.
	     */
	    && (    rrset->rr_type != GETDNS_RRTYPE_DS
	        || !bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA)
		|| *rrset->name == 0
	       )

	    /* If not a DS query, then make sure the NSEC does not contain NS,
	     * or if it does, then also contains SOA, otherwise we have a parent
	     * side delegation point NSEC where we should have gotten a child
	     * side NSEC!
	     */
	    && (    rrset->rr_type == GETDNS_RRTYPE_DS
		|| !bitmap_has_type(bitmap, GETDNS_RRTYPE_NS)
		||  bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA))

	    /* And a valid signature please */
	    && (keytag = a_key_signed_rrset_no_wc(
				    mf, now, skew, keyset, &nsec_rrset))) {

		/* Flag an insecure delegation via opt_out.
		 * See usage of key_proves_nonexistance() from
		 * chain_node_get_trusted_keys() for explanation.
		 */
		if (opt_out && rrset->rr_type == GETDNS_RRTYPE_DS)
			*opt_out =  bitmap_has_type(bitmap, GETDNS_RRTYPE_NS)
			        && !bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA);

		debug_sec_print_rrset("NSEC NODATA proof for: ", rrset);
		return keytag;
	}
	/* More NSEC NODATA cases
	 * ======================
	 * There are a few NSEC NODATA cases where qname doesn't match
	 * NSEC->name:
	 *
	 * - An empty non terminal (ENT) will result in a NSEC covering the
	 *   qname, where qname > NSEC->name and ce(qname) is parent of NXT.
	 *   This case is handled below after the covering NSEC is found.
	 *
	 * - Or a wildcard match without the type.  The wildcard owner name
	 *   match has special handing in the find_nsec_covering_name function.
	 *   We still expect a NSEC covering the name though.
	 */

	/* The NSEC Name error case
	 * ========================
	 * - First find the NSEC that covers the owner name.
	 */
	for ( i = _getdns_rrset_iter_init(&i_spc, rrset->pkt, rrset->pkt_len
	                                        , SECTION_NO_ADDITIONAL)
	    ; i ; i = _getdns_rrset_iter_next(i)) {

		cover = _getdns_rrset_iter_value(i);

		if (/* Is cover an NSEC rrset? */
		       cover->rr_type != GETDNS_RRTYPE_NSEC

		    /* Does it cover the name */
		    || !nsec_covers_name(cover, rrset->name, &ce_name)

		    /* But not a match (because that would be NODATA case) */
		    || _dname_equal(cover->name, rrset->name)

		    /* Get the bitmap rdata field */
		    || !(nsec_rr = _getdns_rrtype_iter_init(&nsec_spc, cover))
		    || !(bitmap = _getdns_rdf_iter_init_at(
				    &bitmap_spc, &nsec_rr->rr_i, 1))

		    /* When qname is a subdomain of the NSEC owner, make
		     * sure there is no DNAME, and no delegation point
		     * there.
		     */
		    || (   _dname_is_parent(cover->name, rrset->name)
		        && (   bitmap_has_type(bitmap, GETDNS_RRTYPE_DNAME)
		            || (    bitmap_has_type(bitmap, GETDNS_RRTYPE_NS)
		                && !bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA)
		               )
		           )
		       )

		    /* And a valid signature please (as always) */
		    || !(keytag = a_key_signed_rrset_no_wc(
					    mf, now, skew, keyset, cover)))
			continue;

		/* We could have found a NSEC covering an Empty Non Terminal.
		 * In that case no NSEC covering the wildcard is needed.
		 * Because it was actually a NODATA proof.
		 *
		 * Empty NON terminals can be identified, by
		 * qname > NSEC->name && NSEC->nxt is subdomain of qname.
		 *
		 * nsec_covers_name() will set ce_name to qname when NSEC->nxt
		 * is a subdomain of qname.
		 */
		if (   dname_compare(rrset->name, cover->name) > 0
		    && dname_compare(rrset->name, ce_name) == 0) {

			debug_sec_print_dname("Empty Non Terminal: ", ce_name);
			return keytag;
		}

		debug_sec_print_dname("Closest Encloser: ", ce_name);

		if (_dname_len(ce_name) > sizeof(wc_name) - 2)
			return 0;
		else
			(void) memcpy(wc_name+2, ce_name, _dname_len(ce_name));

		debug_sec_print_dname("        Wildcard: ", wc_name);

		return find_nsec_covering_name(
		    mf, now, skew, keyset, rrset, wc_name, NULL);
	}

	/* The NSEC3 NODATA case
	 * =====================
	 * NSEC3 has same (hashed) ownername as the rrset to deny.
	 */
	for ( i = _getdns_rrset_iter_init(&i_spc, rrset->pkt, rrset->pkt_len
	                                        , SECTION_NO_ADDITIONAL)
	    ; i ; i = _getdns_rrset_iter_next(i)) {

		/* ce is potentially the NSEC3 that matches complete qname
		 * (so is also the closest encloser)
		 */
		ce = _getdns_rrset_iter_value(i);
		if (    ce->rr_type == GETDNS_RRTYPE_NSEC3

		    /* A NSEC3 RR exists at the owner name of rrset
		     * (this is always true)
		     */
		    && (nsec_rr = _getdns_rrtype_iter_init(&nsec_spc, ce))

		    /* Get the bitmap rdata field */
		    && (bitmap = _getdns_rdf_iter_init_at(
				    &bitmap_spc, &nsec_rr->rr_i, 5))

		    /* At least the rr_type of rrset should be missing */
		    && !bitmap_has_type(bitmap, rrset->rr_type)

		    /* If the name is a CNAME, then we should have gotten it,
		     * So no CNAME bit either.
		     */
		    && !bitmap_has_type(bitmap, GETDNS_RRTYPE_CNAME)

		    /* In case of a DS query, make sure we have the parent side
		     * NSEC and not the child (so no SOA).
		     * (except for the root...)
		     */
		    && (    rrset->rr_type != GETDNS_RRTYPE_DS
			|| !bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA)
		        || *rrset->name == 0
		       )

		    /* If not a DS query, then make sure the NSEC does not
		     * contain NS, or if it does, then also contains SOA,
		     * otherwise we have a parent side delegation point NSEC
		     * where we should have gotten a child side NSEC!
		     */
		    && (    rrset->rr_type == GETDNS_RRTYPE_DS
			|| !bitmap_has_type(bitmap, GETDNS_RRTYPE_NS)
			||  bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA))

		    /* It must have a valid signature */
		    && (keytag = a_key_signed_rrset_no_wc(
					    mf, now, skew, keyset, ce))

		    /* The qname must match the NSEC3 */
		    && (   keytag & NSEC3_ITERATION_COUNT_HIGH
		        || nsec3_matches_name(ce, rrset->name))) {

			/* Flag an insecure delegation via opt_out.
			 * See usage of key_proves_nonexistance() from
			 * chain_node_get_trusted_keys() for explanation.
			 */
			if (opt_out && rrset->rr_type == GETDNS_RRTYPE_DS)
				*opt_out =
				    bitmap_has_type(bitmap, GETDNS_RRTYPE_NS)
				&& !bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA);

			debug_sec_print_rrset("NSEC3 No Data for: ", rrset);
			return keytag;
		}
	}
	/* More NSEC3 NODATA cases
	 * ======================
	 * There are a few NSEC NODATA cases where qname doesn't match
	 * NSEC->name:
	 *
	 * - NSEC3 ownername match for qtype == NSEC3 (TODO?)
	 * - Wildcard NODATA (wildcard owner name match has special handing
	 *                    find_nsec_covering_name())
	 */

	/* The NSEC3 Name error case
	 * ========================+
	 * First find the closest encloser.
	 */
	if (*rrset->name)
	for ( nc_name = rrset->name, ce_name = rrset->name + *rrset->name + 1
	    ; *ce_name ; nc_name = ce_name, ce_name += *ce_name + 1) {

		for ( i = _getdns_rrset_iter_init(&i_spc, rrset->pkt, rrset->pkt_len
		                                        , SECTION_NO_ADDITIONAL)
		    ; i ; i = _getdns_rrset_iter_next(i)) {

			if (   !(ce = _getdns_rrset_iter_value(i))
			    || ce->rr_type != GETDNS_RRTYPE_NSEC3

			    /* Get the bitmap rdata field */
			    || !(nsec_rr = _getdns_rrtype_iter_init(&nsec_spc, ce))
			    || !(bitmap = _getdns_rdf_iter_init_at(
					    &bitmap_spc, &nsec_rr->rr_i, 1))

			    /* No DNAME or delegation point at the closest
			     * encloser.
			     *
			     * TODO: Ask Wouter
			     * Unbound val_nsec3:1024 finishes insecurely
			     * here (instead of bogus) when DS is also missing.
			     * Should we not have followed the delegation then
			     * too?
			     * The NSEC could come from a parent zone!
			     *
			     */
			    || bitmap_has_type(bitmap, GETDNS_RRTYPE_DNAME)
			    || (    bitmap_has_type(bitmap, GETDNS_RRTYPE_NS)
			        && !bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA)
			       )

			    || !(keytag = a_key_signed_rrset_no_wc(
						    mf, now, skew, keyset, ce))
			    || (   !(keytag & NSEC3_ITERATION_COUNT_HIGH)
			        && !nsec3_matches_name(ce, ce_name)))
				continue;

			debug_sec_print_rrset("Closest Encloser: ", ce);
			debug_sec_print_dname("Closest Encloser: ", ce_name);
			debug_sec_print_dname("     Next closer: ", nc_name);

			if (    keytag & NSEC3_ITERATION_COUNT_HIGH
			    || (keytag = nsec3_find_next_closer(mf, now, skew,
					    keyset, rrset, nc_name, opt_out)))

				return keytag;
		}
	}
	return 0;
}

/* Ascend up to the root along chain_nodes.  Try to find a keyset
 * authenticated by a key in ta rrset (trust anchor).  When we found one,
 * descend back down, authenticating more specific keysets along the chain.
 *
 * The most specific keyset is returned in keys.  Also a DNSSEC status is
 * returned.  BOGUS if no keyset could be found.  INSECURE if the
 * non-existence of a DS along the path is proofed, and SECURE otherwise.
 */
static int chain_node_get_trusted_keys(
    const struct mem_funcs *mf, time_t now, uint32_t skew,
    chain_node *node, _getdns_rrset *ta, _getdns_rrset **keys)
{
	int s, keytag;
	int opt_out;

	/* Ascend up to the root */
	if (! node)
		return GETDNS_DNSSEC_BOGUS;

	else if (ta->rr_type == GETDNS_RRTYPE_DS) {

		if ((keytag = ds_authenticates_keys(
		    mf, now, skew, ta, &node->dnskey))) {
			*keys = &node->dnskey;
			node->dnskey_signer = keytag;
			return keytag & NO_SUPPORTED_ALGORITHMS
			     ? GETDNS_DNSSEC_INSECURE
			     : GETDNS_DNSSEC_SECURE;
		}

	} else if (ta->rr_type == GETDNS_RRTYPE_DNSKEY) {

		/* ta is KSK */
		if ((keytag = a_key_signed_rrset_no_wc(
		    mf, now, skew, ta, &node->dnskey))) {
			*keys = &node->dnskey;
			node->dnskey_signer = keytag;
			return GETDNS_DNSSEC_SECURE;
		}
		/* ta is the DNSKEY for this name? */
		if (_dname_equal(ta->name, node->dnskey.name)) {
			*keys = ta;
			return GETDNS_DNSSEC_SECURE;
		}
		/* ta is parent's ZSK proving insecurity below this node? */
		if ((keytag = key_proves_nonexistance(
		    mf, now, skew, ta, &node->ds, &opt_out))) {
			node->ds_signer = keytag;

			/* When the proof is in an opt_out span, result will
			 * be INSECURE regardless the purpose of the searched
			 * for key.
			 *
			 * Otherwise, INSECURE only when this is a zonecut.
			 * i.e. a NODATA proof, with the NS bit and no SOA bit.
			 *
			 * key_proves_nonexistance() will set opt_out also for
			 * these conditions.
			 */
			if (opt_out)
				return GETDNS_DNSSEC_INSECURE;

			/* If this is not an insecurity proof,
			 * continue searching one label up.
			 */

		/* ta is parent's ZSK authenticating DS? */
		} else if ((keytag = a_key_signed_rrset_no_wc(
					mf, now, skew, ta, &node->ds))) {
			node->ds_signer = keytag;
			/* DS should authenticate the DNSKEY rrset now */
			if ((keytag = ds_authenticates_keys(
			    mf, now, skew, &node->ds, &node->dnskey))) {
				*keys = &node->dnskey;
				node->dnskey_signer = keytag;
				return keytag & NO_SUPPORTED_ALGORITHMS
				     ? GETDNS_DNSSEC_INSECURE
				     : GETDNS_DNSSEC_SECURE;
			}
			/* DS without DNSKEY rrset == BOGUS */
			return GETDNS_DNSSEC_BOGUS;
		}
	} else
		return GETDNS_DNSSEC_BOGUS;

	s = chain_node_get_trusted_keys(mf, now, skew, node->parent, ta, keys);
	/* Set dnssec status on root DNSKEY request (for TA management) */
	if (!node->parent && node->dnskey_req &&
	     node->dnskey.name && *node->dnskey.name == 0)
		node->dnskey_req->dnssec_status = s;

	if (s != GETDNS_DNSSEC_SECURE)
		return s;

	/* keys is an authenticated dnskey rrset always now (i.e. ZSK) */
	ta = *keys;
	/* Back down to the head */
	/*************************/
	if ((keytag = key_proves_nonexistance(
	    mf, now, skew, ta, &node->ds, &opt_out))) {
		node->ds_signer = keytag;

		/* When the proof is in an opt_out span, result will be
		 * INSECURE regardless the purpose of the searched for key.
		 *
		 * Otherwise, INSECURE only when this is a zonecut.
		 * i.e. a NODATA proof, with the NS bit, but no SOA bit.
		 *
		 * key_proves_nonexistance() will set opt_out also for these
		 * conditions. (NODATA of DS with NS bit and wihout SOA bit)
		 */
		return opt_out ? GETDNS_DNSSEC_INSECURE
		               : GETDNS_DNSSEC_SECURE;
	}
	if (key_matches_signer(ta, &node->ds)) {

		if ((node->ds_signer = a_key_signed_rrset_no_wc(
						mf, now, skew, ta, &node->ds))
		   && (keytag = ds_authenticates_keys(
				mf, now, skew, &node->ds, &node->dnskey))){

			*keys = &node->dnskey;
			node->dnskey_signer = keytag;
			return keytag & NO_SUPPORTED_ALGORITHMS
			     ? GETDNS_DNSSEC_INSECURE
			     : GETDNS_DNSSEC_SECURE;
		}
		return GETDNS_DNSSEC_BOGUS;
	}
	/* If we are on a zone cut, we must return BOGUS, because there should
	 * have been a more specific DS set.  We can be sure of a zone cut if
	 * a request for the DSset was sent (because they are done only for
	 * signer names and when there was a SOA) or if we do have a DS,
	 * but not signed with a current trusted key.
	 *
	 * For the getdns_validate_dnssec case, we must make sure to insert
	 * an empty DS for this name in the validation chain... so it can
	 * be used for the support_records parameter.
	 */
	if (node->ds_req || _getdns_rrset_has_rrs(&node->ds))
		return GETDNS_DNSSEC_BOGUS;

	/* Not at a zone cut, the trusted keyset must be authenticating
	 * something below (closer to head) this node.
	 */
	return GETDNS_DNSSEC_SECURE;
}

/* The DNSSEC status of the rrset of head is evaluated with trust anchor ta.
 * For this first a secure keyset is looked up, with which the keyset is
 * evaluated.
 */
static int chain_head_validate_with_ta(const struct mem_funcs *mf,
    time_t now, uint32_t skew, chain_head *head, _getdns_rrset *ta)
{
	_getdns_rrset *keys;
	int s, keytag, opt_out;

	_getdns_rrtype_iter nsec_spc, *nsec_rr;
	_getdns_rdf_iter bitmap_spc, *bitmap;
	chain_node *parent;

	debug_sec_print_rrset("Validating ", &head->rrset);
	debug_sec_print_rrset("\twith trust anchor ", ta);

	/* A DS is never at the apex */
	if (   head->rrset.rr_type == GETDNS_RRTYPE_DS
	    && head->parent->parent)
		parent = head->parent->parent;

	/* Only at the apex, a NSEC is signed with a DNSKEY with the same
	 * owner name.  All other are signed by the parent domain or higher.
	 * Besides a shortcut, choosing to search for a trusted key from the
	 * parent is essential for NSECs at a delagation point! (which would
	 * otherwise turn out BOGUS).
	 */
	else if (head->rrset.rr_type == GETDNS_RRTYPE_NSEC
	    &&  head->parent->parent
	    && (nsec_rr = _getdns_rrtype_iter_init(&nsec_spc, &head->rrset))
	    && (bitmap = _getdns_rdf_iter_init_at(
			    &bitmap_spc, &nsec_rr->rr_i, 1))
	    && !bitmap_has_type(bitmap, GETDNS_RRTYPE_SOA))
		parent = head->parent->parent;

	/* NSEC3 is always signed by the parent domain!
	 * ( the ownername of the NSEC3 itself is not in the original zone!
	 *   so a search for a trusted key at that name gives either INSECURE
	 *   (with opt-out) or BOGUS! )
	 */
	else if (head->rrset.rr_type == GETDNS_RRTYPE_NSEC3
	    && head->parent->parent)
		parent = head->parent->parent;
	else
		parent = head->parent;

	if ((s = chain_node_get_trusted_keys(
	    mf, now, skew, parent, ta, &keys)) != GETDNS_DNSSEC_SECURE) {
		debug_sec_print_rrset("Could not get trusted keys "
		                      "for validating ", &head->rrset);
		DEBUG_SEC("\tstatus: %d\n", (int)s);
		return s;
	}
	debug_sec_print_rrset("Validating ", &head->rrset);
	debug_sec_print_rrset("\twith keys ", keys);

	if (_getdns_rrset_has_rrs(&head->rrset)) {
		if ((keytag = a_key_signed_rrset(
		    mf, now, skew, keys, &head->rrset))) {
			DEBUG_SEC("Key %d proved\n", (int)keytag);
			debug_sec_print_rrset("\tSECURE: ", &head->rrset);
			head->signer = keytag;
			return GETDNS_DNSSEC_SECURE;

		} else if (!_getdns_rrset_has_rrsigs(&head->rrset)
				&& (keytag = key_proves_nonexistance(mf, now,
					skew, keys, &head->rrset, &opt_out))
				&& opt_out) {

			DEBUG_SEC("Key %d proved (optout)\n", (int)keytag);
			debug_sec_print_rrset("\tINSECURE: ", &head->rrset);
			head->signer = keytag;
			return GETDNS_DNSSEC_INSECURE;
		}
	} else if ((keytag = key_proves_nonexistance(mf, now, skew,
					keys, &head->rrset, &opt_out))) {
		DEBUG_SEC("Key %d proved (NX)\n", (int)keytag);
		debug_sec_print_rrset("\tSECURE: ", &head->rrset);
		head->signer = keytag;
		return opt_out || (keytag & NSEC3_ITERATION_COUNT_HIGH)
		     ? GETDNS_DNSSEC_INSECURE : GETDNS_DNSSEC_SECURE;
	}
	debug_sec_print_rrset("BOGUS: ", &head->rrset);
	debug_sec_print_rrset("\twith trust anchor: ", ta);
	return GETDNS_DNSSEC_BOGUS;
}

/* The DNSSEC status of the rrset in head is evaluated by trying the trust
 * anchors in tas in turn.  The best outcome counts.
 */
static int chain_head_validate(const struct mem_funcs *mf, time_t now,
    uint32_t skew, chain_head *head, _getdns_rrset_iter *tas)
{
	_getdns_rrset_iter *i;
	_getdns_rrset *ta, dnskey_ta, ds_ta;
	_getdns_rrset_iter closest_ta;
	int closest_labels, s = GETDNS_DNSSEC_INDETERMINATE;
	size_t ta_labels, supported_algorithms;
	_getdns_rrtype_iter rr_spc, *rr;

	/* Find the TA closest to the head's RRset name */
	closest_labels = -1;
	for (i = _getdns_rrset_iter_rewind(tas); i ;i = _getdns_rrset_iter_next(i)) {
		ta = _getdns_rrset_iter_value(i);

		if ((ta->rr_type == GETDNS_RRTYPE_DNSKEY ||
		     ta->rr_type == GETDNS_RRTYPE_DS)
		    && _dname_is_parent(ta->name, head->rrset.name)
		    && (int)(ta_labels = _dname_label_count(ta->name))
		                       > closest_labels ) {

			closest_labels = (int)ta_labels;
			closest_ta = *i;
			if (i->rrset.name == i->name_spc)
				closest_ta.rrset.name = closest_ta.name_spc;
		}
	}
	DEBUG_SEC("closest labels for TA: %d\n", closest_labels);
	if (closest_labels == -1)
		return GETDNS_DNSSEC_INDETERMINATE;

	ta = _getdns_rrset_iter_value(&closest_ta);
	dnskey_ta = *ta;
	dnskey_ta.rr_type = GETDNS_RRTYPE_DNSKEY;
	ds_ta = *ta;
	ds_ta.rr_type = GETDNS_RRTYPE_DS;

	if (!_getdns_rrset_has_rrs(&dnskey_ta))
		return chain_head_validate_with_ta(mf,now,skew,head,&ds_ta);

	/* Does the selected DNSKEY set have supported algorithms? */
	supported_algorithms = 0;
	for ( rr = _getdns_rrtype_iter_init(&rr_spc, ta)
	    ; rr; rr = _getdns_rrtype_iter_next(rr)) {

		if (   rr->rr_i.rr_type + 14 <= rr->rr_i.nxt
		    && _getdns_dnskey_algo_id_is_supported(
			    rr->rr_i.rr_type[13]))

			supported_algorithms++;
	}
	if (!supported_algorithms) {
		if (_getdns_rrset_has_rrs(&ds_ta))
			return chain_head_validate_with_ta(
			    mf, now, skew, head, &ds_ta);

		return GETDNS_DNSSEC_INSECURE;
	}
	s = chain_head_validate_with_ta(mf, now, skew, head, &dnskey_ta);
	if (_getdns_rrset_has_rrs(&ds_ta)) {
		switch (chain_head_validate_with_ta(mf,now,skew,head,&ds_ta)) {
		case GETDNS_DNSSEC_SECURE  : s = GETDNS_DNSSEC_SECURE;
		                             /* fallthrough */
		case GETDNS_DNSSEC_INSECURE: if (s != GETDNS_DNSSEC_SECURE)
						     s = GETDNS_DNSSEC_INSECURE;
					     break;
		case GETDNS_DNSSEC_BOGUS   : if (s != GETDNS_DNSSEC_SECURE &&
						 s != GETDNS_DNSSEC_INSECURE)
						     s = GETDNS_DNSSEC_BOGUS;
					     break;
		default                    : break;
		}
	}
	return s;
}

/* The DNSSEC status of the network requests which constructed the chain is
 * evaluated by processing each head in turn.  The worst outcome per network request
 * is the dnssec status for that network request.
 */
#ifdef STUB_NATIVE_DNSSEC
static void chain_set_netreq_dnssec_status(chain_head *chain, _getdns_rrset_iter *tas)
{
	chain_head *head;

	/* The netreq status is the worst for any head */
	for (head = chain; head; head = head->next) {
		if (!head->netreq)
			continue;

		switch (chain_head_validate(priv_getdns_context_mf(
		    head->netreq->owner->context), time(NULL),
		    head->netreq->owner->context->dnssec_allowed_skew,
		    head, tas)) {

		case GETDNS_DNSSEC_SECURE:
			if (head->netreq->dnssec_status ==
			    GETDNS_DNSSEC_INDETERMINATE)
				head->netreq->dnssec_status =
				    GETDNS_DNSSEC_SECURE;
			break;

		case GETDNS_DNSSEC_INSECURE:
			if (head->netreq->dnssec_status != GETDNS_DNSSEC_BOGUS)
				head->netreq->dnssec_status =
					GETDNS_DNSSEC_INSECURE;
			break;

		case GETDNS_DNSSEC_BOGUS :
			head->netreq->dnssec_status = GETDNS_DNSSEC_BOGUS;
			break;

		default:
			break;
		}
	}
}

static void chain_clear_netreq_dnssec_status(chain_head *chain)
{
	chain_head *head;
	size_t      node_count;
	chain_node *node;

	/* The netreq status is the worst for any head */
	for (head = chain; head; head = head->next) {
		if (!head->netreq)
			continue;

		head->netreq->dnssec_status = GETDNS_DNSSEC_INDETERMINATE;
		for ( node_count = head->node_count, node = head->parent
		    ; node && node_count ; node_count--, node = node->parent ) {

			node->ds_signer = -1;
			node->dnskey_signer = -1;

			if ( ! node->parent && node->dnskey_req
			    && node->dnskey.name && !*node->dnskey.name) {
				node->dnskey_req->dnssec_status =
				    GETDNS_DNSSEC_INDETERMINATE;
			}
		}
	}
}
#endif

/* The DNSSEC status of all heads for a chain structure is evaluated by
 * processing each head in turn.  The worst outcome is the dnssec status for
 * the whole.
 */
static int chain_validate_dnssec(const struct mem_funcs *mf,
    time_t now, uint32_t skew, chain_head *chain, _getdns_rrset_iter *tas)
{
	int s = GETDNS_DNSSEC_INDETERMINATE, t;
	chain_head *head;

	/* The netreq status is the worst for any head */
	for (head = chain; head; head = head->next) {
		t = chain_head_validate(mf, now, skew, head, tas);
		switch (t) {
		case GETDNS_DNSSEC_SECURE:
			if (s == GETDNS_DNSSEC_INDETERMINATE)
				s = GETDNS_DNSSEC_SECURE;
			break;

		case GETDNS_DNSSEC_INSECURE:
			if (s != GETDNS_DNSSEC_BOGUS)
				s = GETDNS_DNSSEC_INSECURE;
			break;

		case GETDNS_DNSSEC_BOGUS :
			s = GETDNS_DNSSEC_BOGUS;
			break;

		default:
			break;
		}
	}
	DEBUG_SEC("chain_validate_dnssec() returning %d\n", s);
	return s;
}


/****************  dnssec_return_validation_chain Extension ******************
 *****************************************************************************/

static size_t count_outstanding_requests(chain_head *head)
{
	size_t count;
	chain_node *node;

	if (!head)
		return 0;

	for ( node = head->parent, count = head->lock
	    ; node
	    ; node = node->parent) {

		count += node->lock;

		if (!_getdns_netreq_finished(node->dnskey_req))
			count++;

		if (!_getdns_netreq_finished(node->ds_req))
			count++;
	}
	return count + count_outstanding_requests(head->next);
}

static int rrset_in_list(_getdns_rrset *rrset, getdns_list *list)
{
	size_t          i;
	getdns_dict    *rr_dict;
	uint32_t        rr_type;
	uint32_t        rr_class;
	getdns_bindata *name;

	for (i = 0; !getdns_list_get_dict(list, i, &rr_dict); i++) {
		if (!getdns_dict_get_int(rr_dict, "type", &rr_type) &&
		    rrset->rr_type == rr_type &&
		    !getdns_dict_get_int(rr_dict, "class", &rr_class) &&
		    rrset->rr_class == rr_class &&
		    !getdns_dict_get_bindata(rr_dict, "name", &name) &&
		    dname_compare(rrset->name, name->data) == 0)
			return 1;
	}
	return 0;
}

static void append_rrset2val_chain_list(
    getdns_list *val_chain_list, _getdns_rrset *rrset, int signer)
{
	_getdns_rr_iter  val_rrset_spc[VAL_RRSET_SPC_SZ];
	_getdns_rr_iter *val_rrset = val_rrset_spc;
	_getdns_rrtype_iter rr_spc, *rr;
	size_t n_rrs, i;
	uint32_t orig_ttl;
	getdns_dict *rr_dict;
	_getdns_rrsig_iter  *rrsig, rrsig_spc;

	assert(val_chain_list && rrset);

	if (signer < 0)
		return;

	for ( rrsig = _getdns_rrsig_iter_init(&rrsig_spc, rrset)
	    ; rrsig &&
	      (   rrsig->rr_i.nxt < rrsig->rr_i.rr_type + 28
	       || gldns_read_uint16(rrsig->rr_i.rr_type + 26)
	          != (signer & 0xFFFF))
	    ; rrsig = _getdns_rrsig_iter_next(rrsig))
		; /* pass */

	if (!rrsig)
		return;

	/* keytag was already read, so orig_ttl should cause no problem */
	assert(rrsig->rr_i.nxt >= rrsig->rr_i.rr_type + 18);

	orig_ttl = gldns_read_uint32(rrsig->rr_i.rr_type + 14);

	for (;;) {
		for ( rr = _getdns_rrtype_iter_init(&rr_spc, rrset), n_rrs = 0
		    ; rr
		    ; rr = _getdns_rrtype_iter_next(rr), n_rrs++) {

			if (n_rrs < VAL_RRSET_SPC_SZ ||
			    val_rrset != val_rrset_spc)
				val_rrset[n_rrs] = rr->rr_i;
		}
		/* Did everything fit? Then break */
		if (val_rrset != val_rrset_spc || n_rrs <= VAL_RRSET_SPC_SZ)
			break;

		/* More space needed for val_rrset */
		val_rrset = GETDNS_XMALLOC(
		    val_chain_list->mf, _getdns_rr_iter, n_rrs);
	}
	qsort(val_rrset, n_rrs, sizeof(_getdns_rr_iter), _rr_iter_rdata_cmp);
	for (i = 0; i < n_rrs; i++) {
		/* Get rid of doubles */
		if (i && !_rr_iter_rdata_cmp(&val_rrset[i], &val_rrset[i-1]))
			continue;

		if (!(rr_dict =  _getdns_rr_iter2rr_dict_canonical(
		    &val_chain_list->mf, &val_rrset[i], &orig_ttl)))
			continue;

		if (_getdns_list_append_this_dict(val_chain_list, rr_dict))
			getdns_dict_destroy(rr_dict);
	}
	if ((rr_dict =  _getdns_rr_iter2rr_dict_canonical(
	    &val_chain_list->mf, &rrsig->rr_i, &orig_ttl)) &&
	    _getdns_list_append_this_dict(val_chain_list, rr_dict))
		getdns_dict_destroy(rr_dict);

	/* Append the other RRSIGs, which were not used for validation too,
	 * because other validators might not have the same algorithm support.
	 */
	for ( rrsig = _getdns_rrsig_iter_init(&rrsig_spc, rrset)
	    ; rrsig
	    ; rrsig = _getdns_rrsig_iter_next(rrsig)) {

		if (rrsig->rr_i.nxt < rrsig->rr_i.rr_type + 28)
			continue;

		if (gldns_read_uint16(rrsig->rr_i.rr_type + 26)
		    == (signer & 0xFFFF))
			continue;

		orig_ttl = gldns_read_uint32(rrsig->rr_i.rr_type + 14);
		if ((rr_dict =  _getdns_rr_iter2rr_dict_canonical(
		    &val_chain_list->mf, &rrsig->rr_i, &orig_ttl)) &&
		    _getdns_list_append_this_dict(val_chain_list, rr_dict))
			getdns_dict_destroy(rr_dict);
	}
	if (val_rrset != val_rrset_spc)
		GETDNS_FREE(val_chain_list->mf, val_rrset);
}

static void append_rrs2val_chain_list(getdns_context *ctxt,
    getdns_list *val_chain_list, getdns_network_req *netreq, int signer)
{
	_getdns_rrset_iter *i, i_spc;
	_getdns_rrset *rrset;
	_getdns_rrtype_iter *rr, rr_spc;
	_getdns_rrsig_iter  *rrsig, rrsig_spc;
	getdns_dict *rr_dict;

	for ( i = _getdns_rrset_iter_init(&i_spc, netreq->response
	                                        , netreq->response_len
	                                        , SECTION_NO_ADDITIONAL)
	    ; i
	    ; i = _getdns_rrset_iter_next(i)) {

		rrset = _getdns_rrset_iter_value(i);

		if (rrset->rr_type == GETDNS_RRTYPE_NSEC   ||
		    rrset->rr_type == GETDNS_RRTYPE_NSEC3) {

			if (rrset_in_list(rrset, val_chain_list))
				continue;

		} else if (rrset->rr_type != GETDNS_RRTYPE_DNSKEY &&
		           rrset->rr_type != GETDNS_RRTYPE_DS)
			continue;

		if (signer > 0) {
			/* We have a signer!  Return RRset in canonical
			 * form and order with only the RRSIG that signed
			 * the RRset.
			 */
			append_rrset2val_chain_list(
			   val_chain_list, rrset, signer);
			continue;
		}
		for ( rr = _getdns_rrtype_iter_init(&rr_spc, rrset)
		    ; rr; rr = _getdns_rrtype_iter_next(rr)) {

			if (!(rr_dict = _getdns_rr_iter2rr_dict(
			    &ctxt->mf, &rr->rr_i)))
				continue;

			if (_getdns_list_append_this_dict(val_chain_list, rr_dict))
				getdns_dict_destroy(rr_dict);
		}
		for ( rrsig = _getdns_rrsig_iter_init(&rrsig_spc, rrset)
		    ; rrsig; rrsig = _getdns_rrsig_iter_next(rrsig)) {

			if (!(rr_dict = _getdns_rr_iter2rr_dict(
						&ctxt->mf, &rrsig->rr_i)))
				continue;

			if (_getdns_list_append_this_dict(val_chain_list, rr_dict))
				getdns_dict_destroy(rr_dict);
		}
	}
}

static void append_empty_ds2val_chain_list(
    getdns_context *context, getdns_list *val_chain_list, _getdns_rrset *ds)
{
	getdns_dict *rr_dict;
	getdns_bindata bindata;
	getdns_dict *rdata_dict;

	if (!(rr_dict = getdns_dict_create_with_context(context)))
		return;

	bindata.size = _dname_len(ds->name);
	bindata.data = (UNCONST_UINT8_p)ds->name;
	(void) getdns_dict_set_bindata(rr_dict, "name", &bindata);
	(void) getdns_dict_set_int(rr_dict, "class", ds->rr_class);
	(void) getdns_dict_set_int(rr_dict, "type", ds->rr_type);
	(void) getdns_dict_set_int(rr_dict, "ttl", 0);

	if (!(rdata_dict = getdns_dict_create_with_context(context))) {
		getdns_dict_destroy(rr_dict);
		return;
	}
	bindata.size = 0;
	bindata.data = NULL;
	(void) getdns_dict_set_bindata(rdata_dict, "rdata_raw", &bindata);
	getdns_dict_destroy(rdata_dict);

	if (_getdns_list_append_this_dict(val_chain_list, rr_dict))
		getdns_dict_destroy(rr_dict);
}
static inline chain_node *_to_the_root(chain_node *node)
{
	while (node->parent) node = node->parent;
	return node;
}

int _getdns_bogus(getdns_dns_req *dnsreq)
{
	getdns_network_req **netreq_p, *netreq;

	for (netreq_p = dnsreq->netreqs; (netreq = *netreq_p) ; netreq_p++) {
		if (netreq->dnssec_status == GETDNS_DNSSEC_BOGUS)
			return 1;
	}
	return 0;
}

static void check_chain_complete(chain_head *chain)
{
	getdns_dns_req *dnsreq;
	getdns_context *context;
	size_t o, node_count;
	chain_head *head, *next, *same_chain;
	chain_node *node;
	getdns_list *val_chain_list;
	getdns_dict *response_dict;
	_getdns_rrset_iter tas_iter;

	if ((o = count_outstanding_requests(chain)) > 0) {
		DEBUG_SEC("%"PRIsz" outstanding requests\n", o);
		return;
	}
	DEBUG_SEC("Chain done!\n");
	dnsreq = chain->netreq->owner;
	context = dnsreq->context;

	if (dnsreq->waiting_for_ta) {
		getdns_dns_req **d;

		for (d = &context->ta_notify; *d; d = &(*d)->ta_notify) {
			if (*d == dnsreq) {
				*d = dnsreq->ta_notify;
				dnsreq->ta_notify = NULL;
				break;
			}
		}

	} else {
		if (context->trust_anchors_source == GETDNS_TASRC_FETCHING) {
			dnsreq->waiting_for_ta = 1;
			dnsreq->ta_notify = context->ta_notify;
			context->ta_notify = dnsreq;
			return;
		}
	}
#ifdef STUB_NATIVE_DNSSEC
	if (context->trust_anchors)

		chain_set_netreq_dnssec_status(chain,_getdns_rrset_iter_init(&tas_iter,
		    context->trust_anchors, context->trust_anchors_len,
		    SECTION_ANSWER));
#else
	if (context->trust_anchors)

		(void) chain_validate_dnssec(priv_getdns_context_mf(context),
		    time(NULL), context->dnssec_allowed_skew,
		    chain, _getdns_rrset_iter_init( &tas_iter
		                          , context->trust_anchors
		                          , context->trust_anchors_len
		                          , SECTION_ANSWER));
#endif
	if (context->trust_anchors_source == GETDNS_TASRC_XML) {
		if ((head = chain) && (node = _to_the_root(head->parent)) &&
		    node->dnskey.name && *node->dnskey.name == 0)
			_getdns_context_update_root_ksk(context,&node->dnskey);

	} else if (_getdns_bogus(dnsreq)) {
		_getdns_rrsig_iter rrsig_spc;

		if ((head = chain) && (node = _to_the_root(head->parent))
 		    /* The root DNSKEY rrset */
		    && node->dnskey.name && *node->dnskey.name == 0
		    /* We queried it and had a response */
		    && node->dnskey_req
		    /* The response was bogus */
		    && node->dnskey_req->dnssec_status == GETDNS_DNSSEC_BOGUS
		    /* The response was bogus, but not because it has no rrsigs */
		    && _getdns_rrsig_iter_init(&rrsig_spc, &node->dnskey)
		    ){

			_getdns_log( &context->log
				   , GETDNS_LOG_SYS_ANCHOR, GETDNS_LOG_NOTICE
				   , "root DNSKEY set was bogus!\n");
			if (!dnsreq->waiting_for_ta) {
				uint64_t now_ms = 0;

				dnsreq->waiting_for_ta = 1;
				_getdns_context_equip_with_anchor(
				    context, &now_ms);

				if (context->trust_anchors_source
				    == GETDNS_TASRC_XML) {
					chain_clear_netreq_dnssec_status(chain);
					check_chain_complete(chain);
					return;
				}
				if (context->trust_anchors_source ==
						GETDNS_TASRC_FAILED
				&& 0 == _getdns_ms_until_expiry2(
				    context->trust_anchors_backoff_expiry,
				    &now_ms)) {
					context->trust_anchors_source =
					    GETDNS_TASRC_NONE;
				}
				if (context->trust_anchors_source
				!=  GETDNS_TASRC_FAILED) {
					_getdns_start_fetching_ta(
					    context,  dnsreq->loop, &now_ms);
				}
				if (dnsreq->waiting_for_ta &&
				    context->trust_anchors_source
				    == GETDNS_TASRC_FETCHING) {

					chain_clear_netreq_dnssec_status(chain);
					dnsreq->ta_notify = context->ta_notify;
					context->ta_notify = dnsreq;
					return;
				}
			}
		}
	}

#ifdef DNSSEC_ROADBLOCK_AVOIDANCE
	if (    dnsreq->dnssec_roadblock_avoidance
	    && !dnsreq->avoid_dnssec_roadblocks
	    &&  _getdns_bogus(dnsreq)) {

		getdns_network_req **netreq_p, *netreq;
		uint64_t now_ms = 0;

		dnsreq->avoid_dnssec_roadblocks = 1;
		dnsreq->chain->lock += 1;

		for ( netreq_p = dnsreq->netreqs
		    ; (netreq = *netreq_p)
		    ; netreq_p++) {

			_getdns_netreq_change_state(netreq, NET_REQ_NOT_SENT);
			netreq->dnssec_status =
				GETDNS_DNSSEC_INDETERMINATE;
			netreq->owner = dnsreq;
			(void) _getdns_submit_netreq(netreq, &now_ms);
		}
		if (!dnsreq->dnssec_return_validation_chain)
			return;

		for ( head = chain; head ; head = next ) {
			next = head->next;
			for ( node_count = head->node_count
			    , node = head->parent
			    ; node_count
			    ; node_count--, node = node->parent ) {

				if (node->dnskey_req) {
					_getdns_netreq_change_state(
					    node->dnskey_req,
					    NET_REQ_NOT_SENT);
					node->dnskey_req->owner->
					    avoid_dnssec_roadblocks = 1;
					(void) _getdns_submit_netreq(
					    node->dnskey_req, &now_ms);
				}
				if (node->ds_req) {
					_getdns_netreq_change_state(
					    node->ds_req, NET_REQ_NOT_SENT);
					node->ds_req->owner->
					    avoid_dnssec_roadblocks = 1;
					(void) _getdns_submit_netreq(
					    node->ds_req, &now_ms);
				}
			}
		}
		return;
	}
#endif
	dnsreq->waiting_for_ta = 0;
	val_chain_list = dnsreq->dnssec_return_validation_chain
		? getdns_list_create_with_context(context) : NULL;

	/* Walk chain to add values to val_chain_list.  We do not cleanup yet.
	 * The chain will eventually be freed when the dns request is descheduled
	 * with getdns_context_clear_outbound_request().
	 */
	for ( head = chain; head ; head = next ) {
		next = head->next;
		if (dnsreq->dnssec_return_full_validation_chain &&
		    head->node_count && head->signer > 0) {

			append_rrset2val_chain_list(
			    val_chain_list, &head->rrset, head->signer);

			for ( same_chain = next
			    ; same_chain && same_chain->signer == head->signer
			    ; same_chain = same_chain->next) {
				append_rrset2val_chain_list(val_chain_list,
				    &same_chain->rrset, same_chain->signer);
				same_chain->signer = -1;
			}
		}
		for ( node_count = head->node_count, node = head->parent
		    ; node_count
		    ; node_count--, node = node->parent ) {

			if (node->dnskey_req) {
				if (val_chain_list)
					append_rrs2val_chain_list(
					    context, val_chain_list,
					    node->dnskey_req,
					    node->dnskey_signer);
			}
			if (node->ds_req) {
				if (val_chain_list)
					append_rrs2val_chain_list(
					    context, val_chain_list,
					    node->ds_req, node->ds_signer);

				if (val_chain_list && node->ds_signer == -1 &&
				    !_getdns_rrset_has_rrs(&node->ds)) {
					/* Add empty DS, to prevent less
					 * specific to be able to authenticate
					 * below a zone cut (closer to head)
					 */
					append_empty_ds2val_chain_list(
					    context, val_chain_list,
					    &node->ds);
				}
			}
		}
	}

	response_dict = _getdns_create_getdns_response(dnsreq);
	if (val_chain_list) {
		if (_getdns_dict_set_this_list(
		    response_dict, "validation_chain", val_chain_list))
			getdns_list_destroy(val_chain_list);
	}

	/* Final user callback */
	dnsreq->validating = 0;
	_getdns_call_user_callback(dnsreq, response_dict);
}

void _getdns_ta_notify_dnsreqs(getdns_context *context)
{
	getdns_dns_req **dnsreq_p, *dnsreq = NULL;
	uint64_t now_ms = 0;

	assert(context);

	if (context->trust_anchors_source == GETDNS_TASRC_NONE ||
	    context->trust_anchors_source == GETDNS_TASRC_FETCHING)
		return;

	dnsreq_p = &context->ta_notify;
	while ((dnsreq = *dnsreq_p)) {
		assert(dnsreq->waiting_for_ta);

		if (dnsreq->chain)
			check_chain_complete(dnsreq->chain);
		else {
			getdns_network_req *netreq, **netreq_p;
			int r = GETDNS_RETURN_GOOD;

			(void) _getdns_context_prepare_for_resolution(context);

			*dnsreq_p = dnsreq->ta_notify;
			for ( netreq_p = dnsreq->netreqs
			    ; !r && (netreq = *netreq_p)
			    ; netreq_p++ ) {

				if (!(r = _getdns_submit_netreq(netreq, &now_ms)))
					continue;
				if (r == DNS_REQ_FINISHED)
					break;
				_getdns_netreq_change_state(netreq, NET_REQ_ERRORED);
			}
		}
		assert(*dnsreq_p != dnsreq);
	}
}

void _getdns_validation_chain_timeout(getdns_dns_req *dnsreq)
{
	cancel_requests_for_subdomains_of(dnsreq->chain, (uint8_t *)"\0");
	dnsreq->request_timed_out = 1;
	check_chain_complete(dnsreq->chain);
}

void _getdns_cancel_validation_chain(getdns_dns_req *dnsreq)
{
	chain_head *head, *next;
	chain_node *node;
	size_t      node_count;

	/* Clear nodes under direct DNSKEY queries.
	 * They share the DNSKEY lookup netreq, but _dnskey_query() can not
	 * be used because we're free'ing the heads.
	 */
	for (head = dnsreq->chain; head; head = head->next) {
		if (  head->rrset.rr_type == GETDNS_RRTYPE_DNSKEY
		   && head->node_count
		   && head->netreq == head->parent->dnskey_req)
			head->parent->dnskey_req = NULL;
	}
	head = dnsreq->chain;
	dnsreq->chain = NULL;
	while (head) {
		next = head->next;

		for ( node_count = head->node_count, node = head->parent
		    ; node_count
		    ; node_count--, node = node->parent ) {

			if (node->dnskey_req)
				_getdns_context_cancel_request(
				    node->dnskey_req->owner);

			if (node->ds_req)
				_getdns_context_cancel_request(
				    node->ds_req->owner);
		}
		GETDNS_FREE(head->my_mf, head);
		head = next;
	}
}

void _getdns_get_validation_chain(getdns_dns_req *dnsreq)
{
	getdns_network_req *netreq, **netreq_p;
	chain_head *chain = NULL, *chain_p;

	if (dnsreq->avoid_dnssec_roadblocks) {
		chain = dnsreq->chain;

	} else if (dnsreq->validating)
		return;
	dnsreq->validating = 1;

	if (dnsreq->avoid_dnssec_roadblocks && chain->lock == 0)
		; /* pass */

	else for (netreq_p = dnsreq->netreqs; (netreq = *netreq_p) ; netreq_p++) {
		if (!  netreq->response
		    || netreq->response_len < GLDNS_HEADER_SIZE
		    || ( GLDNS_RCODE_WIRE(netreq->response)
			 != GETDNS_RCODE_NOERROR &&
			 GLDNS_RCODE_WIRE(netreq->response)
			 != GETDNS_RCODE_NXDOMAIN) ) {

			netreq->dnssec_status = GETDNS_DNSSEC_INSECURE;
			continue;

		} else if (netreq->unbound_id != -1)
			netreq->dnssec_status = GETDNS_DNSSEC_INDETERMINATE;

		add_pkt2val_chain( &dnsreq->my_mf, &chain
		                 , netreq->response, netreq->response_len
				 , netreq
		                 );
		add_question2val_chain( &dnsreq->my_mf, &chain
		                      , netreq->response, netreq->response_len
		                      , netreq->owner->name
		                      , netreq->request_type
		                      , netreq->owner->request_class
				      , netreq
		                      );
	}
	if (chain) {
		for (chain_p = chain; chain_p; chain_p = chain_p->next) {
			if (chain_p->lock) chain_p->lock--;
		}
		dnsreq->chain = chain;
		if (dnsreq->avoid_dnssec_roadblocks && chain->lock)
			chain->lock -= 1;

		check_chain_complete(chain);
	} else {
		dnsreq->validating = 0;
		_getdns_call_user_callback(dnsreq,
		    _getdns_create_getdns_response(dnsreq));
	}
}


/*******************  getdns_validate_dnssec() Function  *********************
 *****************************************************************************/


static int wire_validate_dnssec(const struct mem_funcs *mf,
    time_t now, uint32_t skew, uint8_t *to_val, size_t to_val_len,
    uint8_t *support, size_t support_len, uint8_t *tas, size_t tas_len)
{
	chain_head *chain, *head, *next_head;
	chain_node *node;

	uint8_t qname_spc[256];
	const uint8_t *qname = NULL;
	size_t qname_len = sizeof(qname_spc);
	uint16_t qtype = 0, qclass = GETDNS_RRCLASS_IN;

	_getdns_rr_iter rr_spc, *rr;
	_getdns_rrset_iter tas_iter;

	int s;


	if (to_val_len < GLDNS_HEADER_SIZE)
		return GETDNS_RETURN_GENERIC_ERROR;

#if defined(SEC_DEBUG) && SEC_DEBUG
	char *str = gldns_wire2str_pkt(to_val, to_val_len);
	DEBUG_SEC("to validate: %s\n", str);
	free(str);
#endif

	if (GLDNS_RCODE_WIRE(to_val) != GETDNS_RCODE_NOERROR &&
	    GLDNS_RCODE_WIRE(to_val) != GETDNS_RCODE_NXDOMAIN)
		return GETDNS_DNSSEC_INSECURE;

	if (GLDNS_QDCOUNT(to_val) == 0 && GLDNS_ANCOUNT(to_val) == 0)
		return GETDNS_RETURN_GENERIC_ERROR;

	chain = NULL;
	/* First create a chain (head + nodes) for each rr in the answer and
	 * authority section of the fake to_val packet.
	 */
	add_pkt2val_chain(mf, &chain, to_val, to_val_len, NULL);

	/* For each question in the question section add a chain head.
	 */
	if (   (rr = _getdns_rr_iter_init(&rr_spc, to_val, to_val_len))
	    && _getdns_rr_iter_section(rr) == SECTION_QUESTION
	    && (qname = _getdns_owner_if_or_as_decompressed(
			    rr, qname_spc, &qname_len))
	    && rr->nxt >= rr->rr_type + 4) {

		qtype = gldns_read_uint16(rr->rr_type);
		qclass = gldns_read_uint16(rr->rr_type + 2);

		add_question2val_chain(mf, &chain, to_val, to_val_len,
		    qname, qtype, qclass, NULL);
	}

	/* Now equip the nodes with the support records wireformat */
	for (head = chain; head; head = head->next) {
		for (node = head->parent; node; node = node->parent) {

			node->dnskey.pkt = support;
			node->dnskey.pkt_len = support_len;
			node->ds.pkt = support;
			node->ds.pkt_len = support_len;
		}
	}
	s = chain_validate_dnssec(mf, now, skew, chain,
	    _getdns_rrset_iter_init(
		    &tas_iter, tas, tas_len, SECTION_ANSWER));

	/* Cleanup the chain */
	for (head = chain; head; head = next_head) {
		next_head = head->next;
		GETDNS_FREE(*mf, head);
	}
	return s;
}

/*
 * getdns_validate_dnssec
 *
 */
getdns_return_t
getdns_validate_dnssec2(const getdns_list *records_to_validate,
    const getdns_list *support_records,
    const getdns_list *trust_anchors,
    time_t now, uint32_t skew)
{
	uint8_t to_val_buf[4096], *to_val,
		support_buf[4096], *support,
		tas_buf[4096], *tas;

	size_t to_val_len = sizeof(to_val_buf),
	       support_len = sizeof(support_buf),
	       tas_len = sizeof(tas_buf);

	int r = GETDNS_RETURN_MEMORY_ERROR;
	const struct mem_funcs *mf;

	size_t i;
	getdns_dict *reply;

#if defined(SEC_DEBUG) && SEC_DEBUG
	fflush(stdout);
#endif

	if (!records_to_validate || !trust_anchors)
		return GETDNS_RETURN_INVALID_PARAMETER;
	mf = &records_to_validate->mf;

	/* First convert everything to wire format
	 */

	if (!support_records)
		(void) memset((support = support_buf), 0, GLDNS_HEADER_SIZE);

	else if (!(support = _getdns_list2wire(support_records,
	    support_buf, &support_len, mf)))
		return GETDNS_RETURN_MEMORY_ERROR;

	if (!(tas = _getdns_list2wire(trust_anchors,
	    tas_buf, &tas_len, mf)))
		goto exit_free_support;

	if (!(to_val = _getdns_list2wire(records_to_validate,
	    to_val_buf, &to_val_len, mf)))
		goto exit_free_tas;

	if ((r = wire_validate_dnssec(mf, now, skew, to_val, to_val_len,
	    support,support_len, tas,tas_len)) != GETDNS_RETURN_GENERIC_ERROR)
		goto exit_free_to_val;

	for (i = 0; !getdns_list_get_dict(records_to_validate,i,&reply); i++) {

		DEBUG_SEC("REPLY %"PRIsz", r: %d\n", i, r);
		if (to_val != to_val_buf)
			GETDNS_FREE(*mf, to_val);
		to_val_len = sizeof(to_val_buf);

		if (!(to_val = _getdns_reply2wire(
		    reply, to_val_buf, &to_val_len, mf)))
			continue;

		r = GETDNS_DNSSEC_INDETERMINATE;
		switch (wire_validate_dnssec(mf, now, skew,
		    to_val, to_val_len, support, support_len, tas, tas_len)) {
		case GETDNS_DNSSEC_SECURE:
			if (r == GETDNS_DNSSEC_INDETERMINATE)
				r = GETDNS_DNSSEC_SECURE;
			break;
		case GETDNS_DNSSEC_INSECURE:
			if (r != GETDNS_DNSSEC_BOGUS)
				r = GETDNS_DNSSEC_INSECURE;
			break;
		case GETDNS_DNSSEC_BOGUS:
			r = GETDNS_DNSSEC_BOGUS;
			break;
		default:
			break;
		}
	}
	DEBUG_SEC("REPLY %"PRIsz", r: %d\n", i, r);

exit_free_to_val:
	if (to_val != to_val_buf)
		GETDNS_FREE(*mf, to_val);
exit_free_tas:
	if (tas != tas_buf)
		GETDNS_FREE(*mf, tas);
exit_free_support:
	if (support != support_buf)
		GETDNS_FREE(*mf, support);

	return r;
}


getdns_return_t
getdns_validate_dnssec(const getdns_list *records_to_validate,
    const getdns_list *support_records,
    const getdns_list *trust_anchors)
{
	return getdns_validate_dnssec2(records_to_validate, support_records,
	    trust_anchors, time(NULL), 0);
}

/******************  getdns_root_trust_anchor() Function  ********************
 *****************************************************************************/

uint16_t
_getdns_parse_ta_file(time_t *ta_mtime, gldns_buffer *gbuf)
{

	struct gldns_file_parse_state pst;
	struct stat st;
	uint8_t rr[8192]; /* Reasonable size for a single DNSKEY or DS RR */
	size_t len, dname_len;
	FILE *in;
	uint16_t ta_count = 0;
	size_t pkt_start;

	if (stat(TRUST_ANCHOR_FILE, &st) != 0)
		return 0;

	if (ta_mtime)
		*ta_mtime = st.st_mtime;

	if (!(in = fopen(TRUST_ANCHOR_FILE, "r")))
		return 0;

	memset(&pst, 0, sizeof(pst));
	pst.default_ttl = 3600;
	pst.lineno = 1;

	pkt_start = gldns_buffer_position(gbuf);
	/* Empty header */
	gldns_buffer_write_u32(gbuf, 0);
	gldns_buffer_write_u32(gbuf, 0);
	gldns_buffer_write_u32(gbuf, 0);

	while (!feof(in)) {
		len = sizeof(rr);
		dname_len = 0;
		if (gldns_fp2wire_rr_buf(in, rr, &len, &dname_len, &pst))
			break;
		if (len == 0)  /* empty, $TTL, $ORIGIN */
			continue;
		if (gldns_wirerr_get_type(rr, len, dname_len)
		    != GLDNS_RR_TYPE_DS &&
		    gldns_wirerr_get_type(rr, len, dname_len)
		    != GLDNS_RR_TYPE_DNSKEY)
			continue;

		gldns_buffer_write(gbuf, rr, len);
		ta_count++;
	}
	fclose(in);
	gldns_buffer_write_u16_at(gbuf, pkt_start+GLDNS_ANCOUNT_OFF, ta_count);

	return ta_count;
}

getdns_list *
getdns_root_trust_anchor(time_t *utc_date_of_anchor)
{
	gldns_buffer *gbuf;
	getdns_list *ta_rrs;

	if (!(ta_rrs = getdns_list_create()))
		return NULL;

	if (!(gbuf = gldns_buffer_new(4096)))
		goto error_free_ta_rrs;

	if (!_getdns_parse_ta_file(utc_date_of_anchor, gbuf))
		goto error_free_gbuf;

	_getdns_wire2list( gldns_buffer_begin(gbuf)
	                 , gldns_buffer_position(gbuf), ta_rrs);

	gldns_buffer_free(gbuf);
	return ta_rrs;

error_free_gbuf:
	gldns_buffer_free(gbuf);
error_free_ta_rrs:
	getdns_list_destroy(ta_rrs);
	return NULL;
}

/* dnssec.c */