text: /*
   * validator/val_neg.c - validator aggressive negative caching functions.
   *
   * Copyright (c) 2008, NLnet Labs. All rights reserved.
   *
   * This software is open source.
   * 
   * 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 name of the NLNET LABS 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 THE REGENTS OR CONTRIBUTORS 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.
   */
  
  /**
   * \file
   *
   * This file contains helper functions for the validator module.
   * The functions help with aggressive negative caching.
   * This creates new denials of existance, and proofs for absence of types
   * from cached NSEC records.
   */
  #include "config.h"
  #ifdef HAVE_OPENSSL_SSL_H
  #include "openssl/ssl.h"
  #define NSEC3_SHA_LEN SHA_DIGEST_LENGTH
  #else
  #define NSEC3_SHA_LEN 20
  #endif
  #include "validator/val_neg.h"
  #include "validator/val_nsec.h"
  #include "validator/val_nsec3.h"
  #include "validator/val_utils.h"
  #include "util/data/dname.h"
  #include "util/data/msgreply.h"
  #include "util/log.h"
  #include "util/net_help.h"
  #include "util/config_file.h"
  #include "services/cache/rrset.h"
  #include "services/cache/dns.h"
  #include "ldns/rrdef.h"
  #include "ldns/sbuffer.h"
  
  int val_neg_data_compare(const void* a, const void* b)
  {
  	struct val_neg_data* x = (struct val_neg_data*)a;
  	struct val_neg_data* y = (struct val_neg_data*)b;
  	int m;
  	return dname_canon_lab_cmp(x->name, x->labs, y->name, y->labs, &m);
  }
  
  int val_neg_zone_compare(const void* a, const void* b)
  {
  	struct val_neg_zone* x = (struct val_neg_zone*)a;
  	struct val_neg_zone* y = (struct val_neg_zone*)b;
  	int m;
  	if(x->dclass != y->dclass) {
  		if(x->dclass < y->dclass)
  			return -1;
  		return 1;
  	}
  	return dname_canon_lab_cmp(x->name, x->labs, y->name, y->labs, &m);
  }
  
  struct val_neg_cache* val_neg_create(struct config_file* cfg, size_t maxiter)
  {
  	struct val_neg_cache* neg = (struct val_neg_cache*)calloc(1, 
  		sizeof(*neg));
  	if(!neg) {
  		log_err("Could not create neg cache: out of memory");
  		return NULL;
  	}
  	neg->nsec3_max_iter = maxiter;
  	neg->max = 1024*1024; /* 1 M is thousands of entries */
  	if(cfg) neg->max = cfg->neg_cache_size;
  	rbtree_init(&neg->tree, &val_neg_zone_compare);
  	lock_basic_init(&neg->lock);
  	lock_protect(&neg->lock, neg, sizeof(*neg));
  	return neg;
  }
  
  size_t val_neg_get_mem(struct val_neg_cache* neg)
  {
  	size_t result;
  	lock_basic_lock(&neg->lock);
  	result = sizeof(*neg) + neg->use;
  	lock_basic_unlock(&neg->lock);
  	return result;
  }
  
  /** clear datas on cache deletion */
  static void
  neg_clear_datas(rbnode_t* n, void* ATTR_UNUSED(arg))
  {
  	struct val_neg_data* d = (struct val_neg_data*)n;
  	free(d->name);
  	free(d);
  }
  
  /** clear zones on cache deletion */
  static void
  neg_clear_zones(rbnode_t* n, void* ATTR_UNUSED(arg))
  {
  	struct val_neg_zone* z = (struct val_neg_zone*)n;
  	/* delete all the rrset entries in the tree */
  	traverse_postorder(&z->tree, &neg_clear_datas, NULL);
  	free(z->nsec3_salt);
  	free(z->name);
  	free(z);
  }
  
  void neg_cache_delete(struct val_neg_cache* neg)
  {
  	if(!neg) return;
  	lock_basic_destroy(&neg->lock);
  	/* delete all the zones in the tree */
  	traverse_postorder(&neg->tree, &neg_clear_zones, NULL);
  	free(neg);
  }
  
  /**
   * Put data element at the front of the LRU list.
   * @param neg: negative cache with LRU start and end.
   * @param data: this data is fronted.
   */
  static void neg_lru_front(struct val_neg_cache* neg, 
  	struct val_neg_data* data)
  {
  	data->prev = NULL;
  	data->next = neg->first;
  	if(!neg->first)
  		neg->last = data;
  	else	neg->first->prev = data;
  	neg->first = data;
  }
  
  /**
   * Remove data element from LRU list.
   * @param neg: negative cache with LRU start and end.
   * @param data: this data is removed from the list.
   */
  static void neg_lru_remove(struct val_neg_cache* neg, 
  	struct val_neg_data* data)
  {
  	if(data->prev)
  		data->prev->next = data->next;
  	else	neg->first = data->next;
  	if(data->next)
  		data->next->prev = data->prev;
  	else	neg->last = data->prev;
  }
  
  /**
   * Touch LRU for data element, put it at the start of the LRU list.
   * @param neg: negative cache with LRU start and end.
   * @param data: this data is used.
   */
  static void neg_lru_touch(struct val_neg_cache* neg, 
  	struct val_neg_data* data)
  {
  	if(data == neg->first)
  		return; /* nothing to do */
  	/* remove from current lru position */
  	neg_lru_remove(neg, data);
  	/* add at front */
  	neg_lru_front(neg, data);
  }
  
  /**
   * Delete a zone element from the negative cache.
   * May delete other zone elements to keep tree coherent, or
   * only mark the element as 'not in use'.
   * @param neg: negative cache.
   * @param z: zone element to delete.
   */
  static void neg_delete_zone(struct val_neg_cache* neg, struct val_neg_zone* z)
  {
  	struct val_neg_zone* p, *np;
  	if(!z) return;
  	log_assert(z->in_use);
  	log_assert(z->count > 0);
  	z->in_use = 0;
  
  	/* go up the tree and reduce counts */
  	p = z;
  	while(p) {
  		log_assert(p->count > 0);
  		p->count --;
  		p = p->parent;
  	}
  
  	/* remove zones with zero count */
  	p = z;
  	while(p && p->count == 0) {
  		np = p->parent;
  		(void)rbtree_delete(&neg->tree, &p->node);
  		neg->use -= p->len + sizeof(*p);
  		free(p->nsec3_salt);
  		free(p->name);
  		free(p);
  		p = np;
  	}
  }
  	
  void neg_delete_data(struct val_neg_cache* neg, struct val_neg_data* el)
  {
  	struct val_neg_zone* z;
  	struct val_neg_data* p, *np;
  	if(!el) return;
  	z = el->zone;
  	log_assert(el->in_use);
  	log_assert(el->count > 0);
  	el->in_use = 0;
  
  	/* remove it from the lru list */
  	neg_lru_remove(neg, el);
  	
  	/* go up the tree and reduce counts */
  	p = el;
  	while(p) {
  		log_assert(p->count > 0);
  		p->count --;
  		p = p->parent;
  	}
  
  	/* delete 0 count items from tree */
  	p = el;
  	while(p && p->count == 0) {
  		np = p->parent;
  		(void)rbtree_delete(&z->tree, &p->node);
  		neg->use -= p->len + sizeof(*p);
  		free(p->name);
  		free(p);
  		p = np;
  	}
  
  	/* check if the zone is now unused */
  	if(z->tree.count == 0) {
  		neg_delete_zone(neg, z);
  	}
  }
  
  /**
   * Create more space in negative cache
   * The oldest elements are deleted until enough space is present.
   * Empty zones are deleted.
   * @param neg: negative cache.
   * @param need: how many bytes are needed.
   */
  static void neg_make_space(struct val_neg_cache* neg, size_t need)
  {
  	/* delete elements until enough space or its empty */
  	while(neg->last && neg->max < neg->use + need) {
  		neg_delete_data(neg, neg->last);
  	}
  }
  
  struct val_neg_zone* neg_find_zone(struct val_neg_cache* neg, 
  	uint8_t* nm, size_t len, uint16_t dclass)
  {
  	struct val_neg_zone lookfor;
  	struct val_neg_zone* result;
  	lookfor.node.key = &lookfor;
  	lookfor.name = nm;
  	lookfor.len = len;
  	lookfor.labs = dname_count_labels(lookfor.name);
  	lookfor.dclass = dclass;
  
  	result = (struct val_neg_zone*)
  		rbtree_search(&neg->tree, lookfor.node.key);
  	return result;
  }
  
  /**
   * Find the given data
   * @param zone: negative zone
   * @param nm: what to look for.
   * @param len: length of nm
   * @param labs: labels in nm
   * @return data or NULL if not found.
   */
  static struct val_neg_data* neg_find_data(struct val_neg_zone* zone, 
  	uint8_t* nm, size_t len, int labs)
  {
  	struct val_neg_data lookfor;
  	struct val_neg_data* result;
  	lookfor.node.key = &lookfor;
  	lookfor.name = nm;
  	lookfor.len = len;
  	lookfor.labs = labs;
  
  	result = (struct val_neg_data*)
  		rbtree_search(&zone->tree, lookfor.node.key);
  	return result;
  }
  
  /**
   * Calculate space needed for the data and all its parents
   * @param rep: NSEC entries.
   * @return size.
   */
  static size_t calc_data_need(struct reply_info* rep)
  {
  	uint8_t* d;
  	size_t i, len, res = 0;
  
  	for(i=rep->an_numrrsets; i<rep->an_numrrsets+rep->ns_numrrsets; i++) {
  		if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC) {
  			d = rep->rrsets[i]->rk.dname;
  			len = rep->rrsets[i]->rk.dname_len;
  			res = sizeof(struct val_neg_data) + len;
  			while(!dname_is_root(d)) {
  				log_assert(len > 1); /* not root label */
  				dname_remove_label(&d, &len);
  				res += sizeof(struct val_neg_data) + len;
  			}
  		}
  	}
  	return res;
  }
  
  /**
   * Calculate space needed for zone and all its parents
   * @param d: name of zone
   * @param len: length of name
   * @return size.
   */
  static size_t calc_zone_need(uint8_t* d, size_t len)
  {
  	size_t res = sizeof(struct val_neg_zone) + len;
  	while(!dname_is_root(d)) {
  		log_assert(len > 1); /* not root label */
  		dname_remove_label(&d, &len);
  		res += sizeof(struct val_neg_zone) + len;
  	}
  	return res;
  }
  
  /**
   * Find closest existing parent zone of the given name.
   * @param neg: negative cache.
   * @param nm: name to look for
   * @param nm_len: length of nm
   * @param labs: labelcount of nm.
   * @param qclass: class.
   * @return the zone or NULL if none found.
   */
  static struct val_neg_zone* neg_closest_zone_parent(struct val_neg_cache* neg,
  	uint8_t* nm, size_t nm_len, int labs, uint16_t qclass)
  {
  	struct val_neg_zone key;
  	struct val_neg_zone* result;
  	rbnode_t* res = NULL;
  	key.node.key = &key;
  	key.name = nm;
  	key.len = nm_len;
  	key.labs = labs;
  	key.dclass = qclass;
  	if(rbtree_find_less_equal(&neg->tree, &key, &res)) {
  		/* exact match */
  		result = (struct val_neg_zone*)res;
  	} else {
  		/* smaller element (or no element) */
  		int m;
  		result = (struct val_neg_zone*)res;
  		if(!result || result->dclass != qclass)
  			return NULL;
  		/* count number of labels matched */
  		(void)dname_lab_cmp(result->name, result->labs, key.name,
  			key.labs, &m);
  		while(result) { /* go up until qname is subdomain of stub */
  			if(result->labs <= m)
  				break;
  			result = result->parent;
  		}
  	}
  	return result;
  }
  
  /**
   * Find closest existing parent data for the given name.
   * @param zone: to look in.
   * @param nm: name to look for
   * @param nm_len: length of nm
   * @param labs: labelcount of nm.
   * @return the data or NULL if none found.
   */
  static struct val_neg_data* neg_closest_data_parent(
  	struct val_neg_zone* zone, uint8_t* nm, size_t nm_len, int labs)
  {
  	struct val_neg_data key;
  	struct val_neg_data* result;
  	rbnode_t* res = NULL;
  	key.node.key = &key;
  	key.name = nm;
  	key.len = nm_len;
  	key.labs = labs;
  	if(rbtree_find_less_equal(&zone->tree, &key, &res)) {
  		/* exact match */
  		result = (struct val_neg_data*)res;
  	} else {
  		/* smaller element (or no element) */
  		int m;
  		result = (struct val_neg_data*)res;
  		if(!result)
  			return NULL;
  		/* count number of labels matched */
  		(void)dname_lab_cmp(result->name, result->labs, key.name,
  			key.labs, &m);
  		while(result) { /* go up until qname is subdomain of stub */
  			if(result->labs <= m)
  				break;
  			result = result->parent;
  		}
  	}
  	return result;
  }
  
  /**
   * Create a single zone node
   * @param nm: name for zone (copied)
   * @param nm_len: length of name
   * @param labs: labels in name.
   * @param dclass: class of zone, host order.
   * @return new zone or NULL on failure
   */
  static struct val_neg_zone* neg_setup_zone_node(
  	uint8_t* nm, size_t nm_len, int labs, uint16_t dclass)
  {
  	struct val_neg_zone* zone = 
  		(struct val_neg_zone*)calloc(1, sizeof(*zone));
  	if(!zone) {
  		return NULL;
  	}
  	zone->node.key = zone;
  	zone->name = memdup(nm, nm_len);
  	if(!zone->name) {
  		free(zone);
  		return NULL;
  	}
  	zone->len = nm_len;
  	zone->labs = labs;
  	zone->dclass = dclass;
  
  	rbtree_init(&zone->tree, &val_neg_data_compare);
  	return zone;
  }
  
  /**
   * Create a linked list of parent zones, starting at longname ending on
   * the parent (can be NULL, creates to the root).
   * @param nm: name for lowest in chain
   * @param nm_len: length of name
   * @param labs: labels in name.
   * @param dclass: class of zone.
   * @param parent: NULL for to root, else so it fits under here.
   * @return zone; a chain of zones and their parents up to the parent.
   *  	or NULL on malloc failure
   */
  static struct val_neg_zone* neg_zone_chain(
  	uint8_t* nm, size_t nm_len, int labs, uint16_t dclass,
  	struct val_neg_zone* parent)
  {
  	int i;
  	int tolabs = parent?parent->labs:0;
  	struct val_neg_zone* zone, *prev = NULL, *first = NULL;
  
  	/* create the new subtree, i is labelcount of current creation */
  	/* this creates a 'first' to z->parent=NULL list of zones */
  	for(i=labs; i!=tolabs; i--) {
  		/* create new item */
  		zone = neg_setup_zone_node(nm, nm_len, i, dclass);
  		if(!zone) {
  			/* need to delete other allocations in this routine!*/
  			struct val_neg_zone* p=first, *np;
  			while(p) {
  				np = p->parent;
  				free(p->name);
  				free(p);
  				p = np;
  			}
  			return NULL;
  		}
  		if(i == labs) {
  			first = zone;
  		} else {
  			prev->parent = zone;
  		}
  		/* prepare for next name */
  		prev = zone;
  		dname_remove_label(&nm, &nm_len);
  	}
  	return first;
  }	
  
  void val_neg_zone_take_inuse(struct val_neg_zone* zone)
  {
  	if(!zone->in_use) {
  		struct val_neg_zone* p;
  		zone->in_use = 1;
  		/* increase usage count of all parents */
  		for(p=zone; p; p = p->parent) {
  			p->count++;
  		}
  	}
  }
  
  struct val_neg_zone* neg_create_zone(struct val_neg_cache* neg,
  	uint8_t* nm, size_t nm_len, uint16_t dclass)
  {
  	struct val_neg_zone* zone;
  	struct val_neg_zone* parent;
  	struct val_neg_zone* p, *np;
  	int labs = dname_count_labels(nm);
  
  	/* find closest enclosing parent zone that (still) exists */
  	parent = neg_closest_zone_parent(neg, nm, nm_len, labs, dclass);
  	if(parent && query_dname_compare(parent->name, nm) == 0)
  		return parent; /* already exists, weird */
  	/* if parent exists, it is in use */
  	log_assert(!parent || parent->count > 0);
  	zone = neg_zone_chain(nm, nm_len, labs, dclass, parent);
  	if(!zone) {
  		return NULL;
  	}
  
  	/* insert the list of zones into the tree */
  	p = zone;
  	while(p) {
  		np = p->parent;
  		/* mem use */
  		neg->use += sizeof(struct val_neg_zone) + p->len;
  		/* insert in tree */
  		(void)rbtree_insert(&neg->tree, &p->node);
  		/* last one needs proper parent pointer */
  		if(np == NULL)
  			p->parent = parent;
  		p = np;
  	}
  	return zone;
  }
  
  /** find zone name of message, returns the SOA record */
  static struct ub_packed_rrset_key* reply_find_soa(struct reply_info* rep)
  {
  	size_t i;
  	for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
  		if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_SOA)
  			return rep->rrsets[i];
  	}
  	return NULL;
  }
  
  /** see if the reply has NSEC records worthy of caching */
  static int reply_has_nsec(struct reply_info* rep)
  {
  	size_t i;
  	struct packed_rrset_data* d;
  	if(rep->security != sec_status_secure)
  		return 0;
  	for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
  		if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC) {
  			d = (struct packed_rrset_data*)rep->rrsets[i]->
  				entry.data;
  			if(d->security == sec_status_secure)
  				return 1;
  		}
  	}
  	return 0;
  }
  
  
  /**
   * Create single node of data element.
   * @param nm: name (copied)
   * @param nm_len: length of name
   * @param labs: labels in name.
   * @return element with name nm, or NULL malloc failure.
   */
  static struct val_neg_data* neg_setup_data_node(
  	uint8_t* nm, size_t nm_len, int labs)
  {
  	struct val_neg_data* el;
  	el = (struct val_neg_data*)calloc(1, sizeof(*el));
  	if(!el) {
  		return NULL;
  	}
  	el->node.key = el;
  	el->name = memdup(nm, nm_len);
  	if(!el->name) {
  		free(el);
  		return NULL;
  	}
  	el->len = nm_len;
  	el->labs = labs;
  	return el;
  }
  
  /**
   * Create chain of data element and parents
   * @param nm: name
   * @param nm_len: length of name
   * @param labs: labels in name.
   * @param parent: up to where to make, if NULL up to root label.
   * @return lowest element with name nm, or NULL malloc failure.
   */
  static struct val_neg_data* neg_data_chain(
  	uint8_t* nm, size_t nm_len, int labs, struct val_neg_data* parent)
  {
  	int i;
  	int tolabs = parent?parent->labs:0;
  	struct val_neg_data* el, *first = NULL, *prev = NULL;
  
  	/* create the new subtree, i is labelcount of current creation */
  	/* this creates a 'first' to z->parent=NULL list of zones */
  	for(i=labs; i!=tolabs; i--) {
  		/* create new item */
  		el = neg_setup_data_node(nm, nm_len, i);
  		if(!el) {
  			/* need to delete other allocations in this routine!*/
  			struct val_neg_data* p = first, *np;
  			while(p) {
  				np = p->parent;
  				free(p->name);
  				free(p);
  				p = np;
  			}
  			return NULL;
  		}
  		if(i == labs) {
  			first = el;
  		} else {
  			prev->parent = el;
  		}
  
  		/* prepare for next name */
  		prev = el;
  		dname_remove_label(&nm, &nm_len);
  	}
  	return first;
  }
  
  /**
   * Remove NSEC records between start and end points.
   * By walking the tree, the tree is sorted canonically.
   * @param neg: negative cache.
   * @param zone: the zone
   * @param el: element to start walking at.
   * @param nsec: the nsec record with the end point
   */
  static void wipeout(struct val_neg_cache* neg, struct val_neg_zone* zone, 
  	struct val_neg_data* el, struct ub_packed_rrset_key* nsec)
  {
  	struct packed_rrset_data* d = (struct packed_rrset_data*)nsec->
  		entry.data;
  	uint8_t* end;
  	size_t end_len;
  	int end_labs, m;
  	rbnode_t* walk, *next;
  	struct val_neg_data* cur;
  	uint8_t buf[257];
  	/* get endpoint */
  	if(!d || d->count == 0 || d->rr_len[0] < 2+1)
  		return;
  	if(ntohs(nsec->rk.type) == LDNS_RR_TYPE_NSEC) {
  		end = d->rr_data[0]+2;
  		end_len = dname_valid(end, d->rr_len[0]-2);
  		end_labs = dname_count_labels(end);
  	} else {
  		/* NSEC3 */
  		if(!nsec3_get_nextowner_b32(nsec, 0, buf, sizeof(buf)))
  			return;
  		end = buf;
  		end_labs = dname_count_size_labels(end, &end_len);
  	}
  
  	/* sanity check, both owner and end must be below the zone apex */
  	if(!dname_subdomain_c(el->name, zone->name) || 
  		!dname_subdomain_c(end, zone->name))
  		return;
  
  	/* detect end of zone NSEC ; wipe until the end of zone */
  	if(query_dname_compare(end, zone->name) == 0) {
  		end = NULL;
  	}
  
  	walk = rbtree_next(&el->node);
  	while(walk && walk != RBTREE_NULL) {
  		cur = (struct val_neg_data*)walk;
  		/* sanity check: must be larger than start */
  		if(dname_canon_lab_cmp(cur->name, cur->labs, 
  			el->name, el->labs, &m) <= 0) {
  			/* r == 0 skip original record. */
  			/* r < 0  too small! */
  			walk = rbtree_next(walk);
  			continue;
  		}
  		/* stop at endpoint, also data at empty nonterminals must be
  		 * removed (no NSECs there) so everything between 
  		 * start and end */
  		if(end && dname_canon_lab_cmp(cur->name, cur->labs,
  			end, end_labs, &m) >= 0) {
  			break;
  		}
  		/* this element has to be deleted, but we cannot do it
  		 * now, because we are walking the tree still ... */
  		/* get the next element: */
  		next = rbtree_next(walk);
  		/* now delete the original element, this may trigger
  		 * rbtree rebalances, but really, the next element is
  		 * the one we need.
  		 * But it may trigger delete of other data and the
  		 * entire zone. However, if that happens, this is done
  		 * by deleting the *parents* of the element for deletion,
  		 * and maybe also the entire zone if it is empty. 
  		 * But parents are smaller in canonical compare, thus,
  		 * if a larger element exists, then it is not a parent,
  		 * it cannot get deleted, the zone cannot get empty.
  		 * If the next==NULL, then zone can be empty. */
  		if(cur->in_use)
  			neg_delete_data(neg, cur);
  		walk = next;
  	}
  }
  
  void neg_insert_data(struct val_neg_cache* neg, 
  	struct val_neg_zone* zone, struct ub_packed_rrset_key* nsec)
  {
  	struct packed_rrset_data* d;
  	struct val_neg_data* parent;
  	struct val_neg_data* el;
  	uint8_t* nm = nsec->rk.dname;
  	size_t nm_len = nsec->rk.dname_len;
  	int labs = dname_count_labels(nsec->rk.dname);
  
  	d = (struct packed_rrset_data*)nsec->entry.data;
  	if( !(d->security == sec_status_secure ||
  		(d->security == sec_status_unchecked && d->rrsig_count > 0)))
  		return;
  	log_nametypeclass(VERB_ALGO, "negcache rr", 
  		nsec->rk.dname, ntohs(nsec->rk.type), 
  		ntohs(nsec->rk.rrset_class));
  
  	/* find closest enclosing parent data that (still) exists */
  	parent = neg_closest_data_parent(zone, nm, nm_len, labs);
  	if(parent && query_dname_compare(parent->name, nm) == 0) {
  		/* perfect match already exists */
  		log_assert(parent->count > 0);
  		el = parent;
  	} else { 
  		struct val_neg_data* p, *np;
  
  		/* create subtree for perfect match */
  		/* if parent exists, it is in use */
  		log_assert(!parent || parent->count > 0);
  
  		el = neg_data_chain(nm, nm_len, labs, parent);
  		if(!el) {
  			log_err("out of memory inserting NSEC negative cache");
  			return;
  		}
  		el->in_use = 0; /* set on below */
  
  		/* insert the list of zones into the tree */
  		p = el;
  		while(p) {
  			np = p->parent;
  			/* mem use */
  			neg->use += sizeof(struct val_neg_data) + p->len;
  			/* insert in tree */
  			p->zone = zone;
  			(void)rbtree_insert(&zone->tree, &p->node);
  			/* last one needs proper parent pointer */
  			if(np == NULL)
  				p->parent = parent;
  			p = np;
  		}
  	}
  
  	if(!el->in_use) {
  		struct val_neg_data* p;
  
  		el->in_use = 1;
  		/* increase usage count of all parents */
  		for(p=el; p; p = p->parent) {
  			p->count++;
  		}
  
  		neg_lru_front(neg, el);
  	} else {
  		/* in use, bring to front, lru */
  		neg_lru_touch(neg, el);
  	}
  
  	/* if nsec3 store last used parameters */
  	if(ntohs(nsec->rk.type) == LDNS_RR_TYPE_NSEC3) {
  		int h;
  		uint8_t* s;
  		size_t slen, it;
  		if(nsec3_get_params(nsec, 0, &h, &it, &s, &slen) &&
  			it <= neg->nsec3_max_iter &&
  			(h != zone->nsec3_hash || it != zone->nsec3_iter ||
  			slen != zone->nsec3_saltlen || 
  			memcmp(zone->nsec3_salt, s, slen) != 0)) {
  			uint8_t* sa = memdup(s, slen);
  			if(sa) {
  				free(zone->nsec3_salt);
  				zone->nsec3_salt = sa;
  				zone->nsec3_saltlen = slen;
  				zone->nsec3_hash = h;
  				zone->nsec3_iter = it;
  			}
  		}
  	}
  
  	/* wipe out the cache items between NSEC start and end */
  	wipeout(neg, zone, el, nsec);
  }
  
  void val_neg_addreply(struct val_neg_cache* neg, struct reply_info* rep)
  {
  	size_t i, need;
  	struct ub_packed_rrset_key* soa;
  	struct val_neg_zone* zone;
  	/* see if secure nsecs inside */
  	if(!reply_has_nsec(rep))
  		return;
  	/* find the zone name in message */
  	soa = reply_find_soa(rep);
  	if(!soa)
  		return;
  
  	log_nametypeclass(VERB_ALGO, "negcache insert for zone",
  		soa->rk.dname, LDNS_RR_TYPE_SOA, ntohs(soa->rk.rrset_class));
  	
  	/* ask for enough space to store all of it */
  	need = calc_data_need(rep) + 
  		calc_zone_need(soa->rk.dname, soa->rk.dname_len);
  	lock_basic_lock(&neg->lock);
  	neg_make_space(neg, need);
  
  	/* find or create the zone entry */
  	zone = neg_find_zone(neg, soa->rk.dname, soa->rk.dname_len,
  		ntohs(soa->rk.rrset_class));
  	if(!zone) {
  		if(!(zone = neg_create_zone(neg, soa->rk.dname, 
  			soa->rk.dname_len, ntohs(soa->rk.rrset_class)))) {
  			lock_basic_unlock(&neg->lock);
  			log_err("out of memory adding negative zone");
  			return;
  		}
  	}
  	val_neg_zone_take_inuse(zone);
  
  	/* insert the NSECs */
  	for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
  		if(ntohs(rep->rrsets[i]->rk.type) != LDNS_RR_TYPE_NSEC)
  			continue;
  		if(!dname_subdomain_c(rep->rrsets[i]->rk.dname, 
  			zone->name)) continue;
  		/* insert NSEC into this zone's tree */
  		neg_insert_data(neg, zone, rep->rrsets[i]);
  	}
  	if(zone->tree.count == 0) {
  		/* remove empty zone if inserts failed */
  		neg_delete_zone(neg, zone);
  	}
  	lock_basic_unlock(&neg->lock);
  }
  
  /**
   * Lookup closest data record. For NSEC denial.
   * @param zone: zone to look in
   * @param qname: name to look for.
   * @param len: length of name
   * @param labs: labels in name
   * @param data: data element, exact or smaller or NULL
   * @return true if exact match.
   */
  static int neg_closest_data(struct val_neg_zone* zone,
  	uint8_t* qname, size_t len, int labs, struct val_neg_data** data)
  {
  	struct val_neg_data key;
  	rbnode_t* r;
  	key.node.key = &key;
  	key.name = qname;
  	key.len = len;
  	key.labs = labs;
  	if(rbtree_find_less_equal(&zone->tree, &key, &r)) {
  		/* exact match */
  		*data = (struct val_neg_data*)r;
  		return 1;
  	} else {
  		/* smaller match */
  		*data = (struct val_neg_data*)r;
  		return 0;
  	}
  }
  
  int val_neg_dlvlookup(struct val_neg_cache* neg, uint8_t* qname, size_t len,
          uint16_t qclass, struct rrset_cache* rrset_cache, time_t now)
  {
  	/* lookup closest zone */
  	struct val_neg_zone* zone;
  	struct val_neg_data* data;
  	int labs;
  	struct ub_packed_rrset_key* nsec;
  	struct packed_rrset_data* d;
  	uint32_t flags;
  	uint8_t* wc;
  	struct query_info qinfo;
  	if(!neg) return 0;
  
  	log_nametypeclass(VERB_ALGO, "negcache dlvlookup", qname, 
  		LDNS_RR_TYPE_DLV, qclass);
  	
  	labs = dname_count_labels(qname);
  	lock_basic_lock(&neg->lock);
  	zone = neg_closest_zone_parent(neg, qname, len, labs, qclass);
  	while(zone && !zone->in_use)
  		zone = zone->parent;
  	if(!zone) {
  		lock_basic_unlock(&neg->lock);
  		return 0;
  	}
  	log_nametypeclass(VERB_ALGO, "negcache zone", zone->name, 0, 
  		zone->dclass);
  
  	/* DLV is defined to use NSEC only */
  	if(zone->nsec3_hash) {
  		lock_basic_unlock(&neg->lock);
  		return 0;
  	}
  
  	/* lookup closest data record */
  	(void)neg_closest_data(zone, qname, len, labs, &data);
  	while(data && !data->in_use)
  		data = data->parent;
  	if(!data) {
  		lock_basic_unlock(&neg->lock);
  		return 0;
  	}
  	log_nametypeclass(VERB_ALGO, "negcache rr", data->name, 
  		LDNS_RR_TYPE_NSEC, zone->dclass);
  
  	/* lookup rrset in rrset cache */
  	flags = 0;
  	if(query_dname_compare(data->name, zone->name) == 0)
  		flags = PACKED_RRSET_NSEC_AT_APEX;
  	nsec = rrset_cache_lookup(rrset_cache, data->name, data->len,
  		LDNS_RR_TYPE_NSEC, zone->dclass, flags, now, 0);
  
  	/* check if secure and TTL ok */
  	if(!nsec) {
  		lock_basic_unlock(&neg->lock);
  		return 0;
  	}
  	d = (struct packed_rrset_data*)nsec->entry.data;
  	if(!d || now > d->ttl) {
  		lock_rw_unlock(&nsec->entry.lock);
  		/* delete data record if expired */
  		neg_delete_data(neg, data);
  		lock_basic_unlock(&neg->lock);
  		return 0;
  	}
  	if(d->security != sec_status_secure) {
  		lock_rw_unlock(&nsec->entry.lock);
  		neg_delete_data(neg, data);
  		lock_basic_unlock(&neg->lock);
  		return 0;
  	}
  	verbose(VERB_ALGO, "negcache got secure rrset");
  
  	/* check NSEC security */
  	/* check if NSEC proves no DLV type exists */
  	/* check if NSEC proves NXDOMAIN for qname */
  	qinfo.qname = qname;
  	qinfo.qtype = LDNS_RR_TYPE_DLV;
  	qinfo.qclass = qclass;
  	if(!nsec_proves_nodata(nsec, &qinfo, &wc) &&
  		!val_nsec_proves_name_error(nsec, qname)) {
  		/* the NSEC is not a denial for the DLV */
  		lock_rw_unlock(&nsec->entry.lock);
  		lock_basic_unlock(&neg->lock);
  		verbose(VERB_ALGO, "negcache not proven");
  		return 0;
  	}
  	/* so the NSEC was a NODATA proof, or NXDOMAIN proof. */
  
  	/* no need to check for wildcard NSEC; no wildcards in DLV repos */
  	/* no need to lookup SOA record for client; no response message */
  
  	lock_rw_unlock(&nsec->entry.lock);
  	/* if OK touch the LRU for neg_data element */
  	neg_lru_touch(neg, data);
  	lock_basic_unlock(&neg->lock);
  	verbose(VERB_ALGO, "negcache DLV denial proven");
  	return 1;
  }
  
  /** see if the reply has signed NSEC records and return the signer */
  static uint8_t* reply_nsec_signer(struct reply_info* rep, size_t* signer_len,
  	uint16_t* dclass)
  {
  	size_t i;
  	struct packed_rrset_data* d;
  	uint8_t* s;
  	for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
  		if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC ||
  			ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC3) {
  			d = (struct packed_rrset_data*)rep->rrsets[i]->
  				entry.data;
  			/* return first signer name of first NSEC */
  			if(d->rrsig_count != 0) {
  				val_find_rrset_signer(rep->rrsets[i],
  					&s, signer_len);
  				if(s && *signer_len) {
  					*dclass = ntohs(rep->rrsets[i]->
  						rk.rrset_class);
  					return s;
  				}
  			}
  		}
  	}
  	return 0;
  }
  
  void val_neg_addreferral(struct val_neg_cache* neg, struct reply_info* rep,
  	uint8_t* zone_name)
  {
  	size_t i, need;
  	uint8_t* signer;
  	size_t signer_len;
  	uint16_t dclass;
  	struct val_neg_zone* zone;
  	/* no SOA in this message, find RRSIG over NSEC's signer name.
  	 * note the NSEC records are maybe not validated yet */
  	signer = reply_nsec_signer(rep, &signer_len, &dclass);
  	if(!signer) 
  		return;
  	if(!dname_subdomain_c(signer, zone_name)) {
  		/* the signer is not in the bailiwick, throw it out */
  		return;
  	}
  
  	log_nametypeclass(VERB_ALGO, "negcache insert referral ",
  		signer, LDNS_RR_TYPE_NS, dclass);
  	
  	/* ask for enough space to store all of it */
  	need = calc_data_need(rep) + calc_zone_need(signer, signer_len);
  	lock_basic_lock(&neg->lock);
  	neg_make_space(neg, need);
  
  	/* find or create the zone entry */
  	zone = neg_find_zone(neg, signer, signer_len, dclass);
  	if(!zone) {
  		if(!(zone = neg_create_zone(neg, signer, signer_len, 
  			dclass))) {
  			lock_basic_unlock(&neg->lock);
  			log_err("out of memory adding negative zone");
  			return;
  		}
  	}
  	val_neg_zone_take_inuse(zone);
  
  	/* insert the NSECs */
  	for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
  		if(ntohs(rep->rrsets[i]->rk.type) != LDNS_RR_TYPE_NSEC &&
  			ntohs(rep->rrsets[i]->rk.type) != LDNS_RR_TYPE_NSEC3)
  			continue;
  		if(!dname_subdomain_c(rep->rrsets[i]->rk.dname, 
  			zone->name)) continue;
  		/* insert NSEC into this zone's tree */
  		neg_insert_data(neg, zone, rep->rrsets[i]);
  	}
  	if(zone->tree.count == 0) {
  		/* remove empty zone if inserts failed */
  		neg_delete_zone(neg, zone);
  	}
  	lock_basic_unlock(&neg->lock);
  }
  
  /**
   * Check that an NSEC3 rrset does not have a type set.
   * None of the nsec3s in a hash-collision are allowed to have the type.
   * (since we do not know which one is the nsec3 looked at, flags, ..., we
   * ignore the cached item and let it bypass negative caching).
   * @param k: the nsec3 rrset to check.
   * @param t: type to check
   * @return true if no RRs have the type.
   */
  static int nsec3_no_type(struct ub_packed_rrset_key* k, uint16_t t)
  {
  	int count = (int)((struct packed_rrset_data*)k->entry.data)->count;
  	int i;
  	for(i=0; i<count; i++)
  		if(nsec3_has_type(k, i, t))
  			return 0;
  	return 1;
  }
  
  /**
   * See if rrset exists in rrset cache.
   * If it does, the bit is checked, and if not expired, it is returned
   * allocated in region.
   * @param rrset_cache: rrset cache
   * @param qname: to lookup rrset name
   * @param qname_len: length of qname.
   * @param qtype: type of rrset to lookup, host order
   * @param qclass: class of rrset to lookup, host order
   * @param flags: flags for rrset to lookup
   * @param region: where to alloc result
   * @param checkbit: if true, a bit in the nsec typemap is checked for absence.
   * @param checktype: which bit to check
   * @param now: to check ttl against
   * @return rrset or NULL
   */
  static struct ub_packed_rrset_key*
  grab_nsec(struct rrset_cache* rrset_cache, uint8_t* qname, size_t qname_len,
  	uint16_t qtype, uint16_t qclass, uint32_t flags, 
  	struct regional* region, int checkbit, uint16_t checktype, 
  	time_t now)
  {
  	struct ub_packed_rrset_key* r, *k = rrset_cache_lookup(rrset_cache,
  		qname, qname_len, qtype, qclass, flags, now, 0);
  	struct packed_rrset_data* d;
  	if(!k) return NULL;
  	d = (struct packed_rrset_data*)k->entry.data;
  	if(d->ttl < now) {
  		lock_rw_unlock(&k->entry.lock);
  		return NULL;
  	}
  	/* only secure or unchecked records that have signatures. */
  	if( ! ( d->security == sec_status_secure ||
  		(d->security == sec_status_unchecked &&
  		d->rrsig_count > 0) ) ) {
  		lock_rw_unlock(&k->entry.lock);
  		return NULL;
  	}
  	/* check if checktype is absent */
  	if(checkbit && (
  		(qtype == LDNS_RR_TYPE_NSEC && nsec_has_type(k, checktype)) ||
  		(qtype == LDNS_RR_TYPE_NSEC3 && !nsec3_no_type(k, checktype))
  		)) {
  		lock_rw_unlock(&k->entry.lock);
  		return NULL;
  	}
  	/* looks OK! copy to region and return it */
  	r = packed_rrset_copy_region(k, region, now);
  	/* if it failed, we return the NULL */
  	lock_rw_unlock(&k->entry.lock);
  	return r;
  }
  
  /** find nsec3 closest encloser in neg cache */
  static struct val_neg_data*
  neg_find_nsec3_ce(struct val_neg_zone* zone, uint8_t* qname, size_t qname_len,
  		int qlabs, sldns_buffer* buf, uint8_t* hashnc, size_t* nclen)
  {
  	struct val_neg_data* data;
  	uint8_t hashce[NSEC3_SHA_LEN];
  	uint8_t b32[257];
  	size_t celen, b32len;
  
  	*nclen = 0;
  	while(qlabs > 0) {
  		/* hash */
  		if(!(celen=nsec3_get_hashed(buf, qname, qname_len, 
  			zone->nsec3_hash, zone->nsec3_iter, zone->nsec3_salt, 
  			zone->nsec3_saltlen, hashce, sizeof(hashce))))
  			return NULL;
  		if(!(b32len=nsec3_hash_to_b32(hashce, celen, zone->name,
  			zone->len, b32, sizeof(b32))))
  			return NULL;
  
  		/* lookup (exact match only) */
  		data = neg_find_data(zone, b32, b32len, zone->labs+1);
  		if(data && data->in_use) {
  			/* found ce match! */
  			return data;
  		}
  
  		*nclen = celen;
  		memmove(hashnc, hashce, celen);
  		dname_remove_label(&qname, &qname_len);
  		qlabs --;
  	}
  	return NULL;
  }
  
  /** check nsec3 parameters on nsec3 rrset with current zone values */
  static int
  neg_params_ok(struct val_neg_zone* zone, struct ub_packed_rrset_key* rrset)
  {
  	int h;
  	uint8_t* s;
  	size_t slen, it;
  	if(!nsec3_get_params(rrset, 0, &h, &it, &s, &slen))
  		return 0;
  	return (h == zone->nsec3_hash && it == zone->nsec3_iter &&
  		slen == zone->nsec3_saltlen &&
  		memcmp(zone->nsec3_salt, s, slen) == 0);
  }
  
  /** get next closer for nsec3 proof */
  static struct ub_packed_rrset_key*
  neg_nsec3_getnc(struct val_neg_zone* zone, uint8_t* hashnc, size_t nclen,
  	struct rrset_cache* rrset_cache, struct regional* region, 
  	time_t now, uint8_t* b32, size_t maxb32)
  {
  	struct ub_packed_rrset_key* nc_rrset;
  	struct val_neg_data* data;
  	size_t b32len;
  
  	if(!(b32len=nsec3_hash_to_b32(hashnc, nclen, zone->name,
  		zone->len, b32, maxb32)))
  		return NULL;
  	(void)neg_closest_data(zone, b32, b32len, zone->labs+1, &data);
  	if(!data && zone->tree.count != 0) {
  		/* could be before the first entry ; return the last
  		 * entry (possibly the rollover nsec3 at end) */
  		data = (struct val_neg_data*)rbtree_last(&zone->tree);
  	}
  	while(data && !data->in_use)
  		data = data->parent;
  	if(!data)
  		return NULL;
  	/* got a data element in tree, grab it */
  	nc_rrset = grab_nsec(rrset_cache, data->name, data->len, 
  		LDNS_RR_TYPE_NSEC3, zone->dclass, 0, region, 0, 0, now);
  	if(!nc_rrset)
  		return NULL;
  	if(!neg_params_ok(zone, nc_rrset))
  		return NULL;
  	return nc_rrset;
  }
  
  /** neg cache nsec3 proof procedure*/
  static struct dns_msg*
  neg_nsec3_proof_ds(struct val_neg_zone* zone, uint8_t* qname, size_t qname_len,
  		int qlabs, sldns_buffer* buf, struct rrset_cache* rrset_cache,
  		struct regional* region, time_t now, uint8_t* topname)
  {
  	struct dns_msg* msg;
  	struct val_neg_data* data;
  	uint8_t hashnc[NSEC3_SHA_LEN];
  	size_t nclen;
  	struct ub_packed_rrset_key* ce_rrset, *nc_rrset;
  	struct nsec3_cached_hash c;
  	uint8_t nc_b32[257];
  
  	/* for NSEC3 ; determine the closest encloser for which we
  	 * can find an exact match. Remember the hashed lower name,
  	 * since that is the one we need a closest match for. 
  	 * If we find a match straight away, then it becomes NODATA.
  	 * Otherwise, NXDOMAIN or if OPTOUT, an insecure delegation.
  	 * Also check that parameters are the same on closest encloser
  	 * and on closest match.
  	 */
  	if(!zone->nsec3_hash) 
  		return NULL; /* not nsec3 zone */
  
  	if(!(data=neg_find_nsec3_ce(zone, qname, qname_len, qlabs, buf,
  		hashnc, &nclen))) {
  		return NULL;
  	}
  
  	/* grab the ce rrset */
  	ce_rrset = grab_nsec(rrset_cache, data->name, data->len, 
  		LDNS_RR_TYPE_NSEC3, zone->dclass, 0, region, 1, 
  		LDNS_RR_TYPE_DS, now);
  	if(!ce_rrset)
  		return NULL;
  	if(!neg_params_ok(zone, ce_rrset))
  		return NULL;
  
  	if(nclen == 0) {
  		/* exact match, just check the type bits */
  		/* need: -SOA, -DS, +NS */
  		if(nsec3_has_type(ce_rrset, 0, LDNS_RR_TYPE_SOA) ||
  			nsec3_has_type(ce_rrset, 0, LDNS_RR_TYPE_DS) ||
  			!nsec3_has_type(ce_rrset, 0, LDNS_RR_TYPE_NS))
  			return NULL;
  		if(!(msg = dns_msg_create(qname, qname_len, 
  			LDNS_RR_TYPE_DS, zone->dclass, region, 1))) 
  			return NULL;
  		/* TTL reduced in grab_nsec */
  		if(!dns_msg_authadd(msg, region, ce_rrset, 0)) 
  			return NULL;
  		return msg;
  	}
  
  	/* optout is not allowed without knowing the trust-anchor in use,
  	 * otherwise the optout could spoof away that anchor */
  	if(!topname)
  		return NULL;
  
  	/* if there is no exact match, it must be in an optout span
  	 * (an existing DS implies an NSEC3 must exist) */
  	nc_rrset = neg_nsec3_getnc(zone, hashnc, nclen, rrset_cache, 
  		region, now, nc_b32, sizeof(nc_b32));
  	if(!nc_rrset) 
  		return NULL;
  	if(!neg_params_ok(zone, nc_rrset))
  		return NULL;
  	if(!nsec3_has_optout(nc_rrset, 0))
  		return NULL;
  	c.hash = hashnc;
  	c.hash_len = nclen;
  	c.b32 = nc_b32+1;
  	c.b32_len = (size_t)nc_b32[0];
  	if(nsec3_covers(zone->name, &c, nc_rrset, 0, buf)) {
  		/* nc_rrset covers the next closer name.
  		 * ce_rrset equals a closer encloser.
  		 * nc_rrset is optout.
  		 * No need to check wildcard for type DS */
  		/* capacity=3: ce + nc + soa(if needed) */
  		if(!(msg = dns_msg_create(qname, qname_len, 
  			LDNS_RR_TYPE_DS, zone->dclass, region, 3))) 
  			return NULL;
  		/* now=0 because TTL was reduced in grab_nsec */
  		if(!dns_msg_authadd(msg, region, ce_rrset, 0)) 
  			return NULL;
  		if(!dns_msg_authadd(msg, region, nc_rrset, 0)) 
  			return NULL;
  		return msg;
  	}
  	return NULL;
  }
  
  /**
   * Add SOA record for external responses.
   * @param rrset_cache: to look into.
   * @param now: current time.
   * @param region: where to perform the allocation
   * @param msg: current msg with NSEC.
   * @param zone: val_neg_zone if we have one.
   * @return false on lookup or alloc failure.
   */
  static int add_soa(struct rrset_cache* rrset_cache, time_t now,
  	struct regional* region, struct dns_msg* msg, struct val_neg_zone* zone)
  {
  	struct ub_packed_rrset_key* soa;
  	uint8_t* nm;
  	size_t nmlen;
  	uint16_t dclass;
  	if(zone) {
  		nm = zone->name;
  		nmlen = zone->len;
  		dclass = zone->dclass;
  	} else {
  		/* Assumes the signer is the zone SOA to add */
  		nm = reply_nsec_signer(msg->rep, &nmlen, &dclass);
  		if(!nm) 
  			return 0;
  	}
  	soa = rrset_cache_lookup(rrset_cache, nm, nmlen, LDNS_RR_TYPE_SOA, 
  		dclass, PACKED_RRSET_SOA_NEG, now, 0);
  	if(!soa)
  		return 0;
  	if(!dns_msg_authadd(msg, region, soa, now)) {
  		lock_rw_unlock(&soa->entry.lock);
  		return 0;
  	}
  	lock_rw_unlock(&soa->entry.lock);
  	return 1;
  }
  
  struct dns_msg* 
  val_neg_getmsg(struct val_neg_cache* neg, struct query_info* qinfo, 
  	struct regional* region, struct rrset_cache* rrset_cache, 
  	sldns_buffer* buf, time_t now, int addsoa, uint8_t* topname)
  {
  	struct dns_msg* msg;
  	struct ub_packed_rrset_key* rrset;
  	uint8_t* zname;
  	size_t zname_len;
  	int zname_labs;
  	struct val_neg_zone* zone;
  
  	/* only for DS queries */
  	if(qinfo->qtype != LDNS_RR_TYPE_DS)
  		return NULL;
  	log_assert(!topname || dname_subdomain_c(qinfo->qname, topname));
  
  	/* see if info from neg cache is available 
  	 * For NSECs, because there is no optout; a DS next to a delegation
  	 * always has exactly an NSEC for it itself; check its DS bit.
  	 * flags=0 (not the zone apex).
  	 */
  	rrset = grab_nsec(rrset_cache, qinfo->qname, qinfo->qname_len,
  		LDNS_RR_TYPE_NSEC, qinfo->qclass, 0, region, 1, 
  		qinfo->qtype, now);
  	if(rrset) {
  		/* return msg with that rrset */
  		if(!(msg = dns_msg_create(qinfo->qname, qinfo->qname_len, 
  			qinfo->qtype, qinfo->qclass, region, 2))) 
  			return NULL;
  		/* TTL already subtracted in grab_nsec */
  		if(!dns_msg_authadd(msg, region, rrset, 0)) 
  			return NULL;
  		if(addsoa && !add_soa(rrset_cache, now, region, msg, NULL))
  			return NULL;
  		return msg;
  	}
  
  	/* check NSEC3 neg cache for type DS */
  	/* need to look one zone higher for DS type */
  	zname = qinfo->qname;
  	zname_len = qinfo->qname_len;
  	dname_remove_label(&zname, &zname_len);
  	zname_labs = dname_count_labels(zname);
  
  	/* lookup closest zone */
  	lock_basic_lock(&neg->lock);
  	zone = neg_closest_zone_parent(neg, zname, zname_len, zname_labs, 
  		qinfo->qclass);
  	while(zone && !zone->in_use)
  		zone = zone->parent;
  	/* check that the zone is not too high up so that we do not pick data
  	 * out of a zone that is above the last-seen key (or trust-anchor). */
  	if(zone && topname) {
  		if(!dname_subdomain_c(zone->name, topname))
  			zone = NULL;
  	}
  	if(!zone) {
  		lock_basic_unlock(&neg->lock);
  		return NULL;
  	}
  
  	msg = neg_nsec3_proof_ds(zone, qinfo->qname, qinfo->qname_len, 
  		zname_labs+1, buf, rrset_cache, region, now, topname);
  	if(msg && addsoa && !add_soa(rrset_cache, now, region, msg, zone)) {
  		lock_basic_unlock(&neg->lock);
  		return NULL;
  	}
  	lock_basic_unlock(&neg->lock);
  	return msg;
  }
  