/*
 * validator/val_nsec3.c - validator NSEC3 denial of existence functions.
 *
 * Copyright (c) 2007, 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 COPYRIGHT
 * HOLDER 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 NSEC3 checking, the different NSEC3 proofs
 * for denial of existence, and proofs for presence of types.
 */
#include "config.h"
#include <ctype.h>
#include "validator/val_nsec3.h"
#include "validator/val_secalgo.h"
#include "validator/validator.h"
#include "validator/val_kentry.h"
#include "services/cache/rrset.h"
#include "util/regional.h"
#include "util/rbtree.h"
#include "util/module.h"
#include "util/net_help.h"
#include "util/data/packed_rrset.h"
#include "util/data/dname.h"
#include "util/data/msgreply.h"
/* we include nsec.h for the bitmap_has_type function */
#include "validator/val_nsec.h"
#include "sldns/sbuffer.h"
#include "util/config_file.h"

/**
 * Max number of NSEC3 calculations at once, suspend query for later.
 * 8 is low enough and allows for cases where multiple proofs are needed.
 */
#define MAX_NSEC3_CALCULATIONS 8
/**
 * When all allowed NSEC3 calculations at once resulted in error treat as
 * bogus. NSEC3 hash errors are not cached and this helps breaks loops with
 * erroneous data.
 */
#define MAX_NSEC3_ERRORS -1

/** 
 * This function we get from ldns-compat or from base system 
 * it returns the number of data bytes stored at the target, or <0 on error.
 */
int sldns_b32_ntop_extended_hex(uint8_t const *src, size_t srclength,
        char *target, size_t targsize);
/** 
 * This function we get from ldns-compat or from base system 
 * it returns the number of data bytes stored at the target, or <0 on error.
 */
int sldns_b32_pton_extended_hex(char const *src, size_t hashed_owner_str_len, 
        uint8_t *target, size_t targsize);

/**
 * Closest encloser (ce) proof results
 * Contains the ce and the next-closer (nc) proof.
 */
struct ce_response {
        /** the closest encloser name */
        uint8_t* ce;
        /** length of ce */
        size_t ce_len;
        /** NSEC3 record that proved ce. rrset */
        struct ub_packed_rrset_key* ce_rrset;
        /** NSEC3 record that proved ce. rr number */
        int ce_rr;
        /** NSEC3 record that proved nc. rrset */
        struct ub_packed_rrset_key* nc_rrset;
        /** NSEC3 record that proved nc. rr*/
        int nc_rr;
};

/**
 * Filter conditions for NSEC3 proof
 * Used to iterate over the applicable NSEC3 RRs.
 */
struct nsec3_filter {
        /** Zone name, only NSEC3 records for this zone are considered */
        uint8_t* zone;
        /** length of the zonename */
        size_t zone_len;
        /** the list of NSEC3s to filter; array */
        struct ub_packed_rrset_key** list;
        /** number of rrsets in list */
        size_t num;
        /** class of records for the NSEC3, only this class applies */
        uint16_t fclass;
};

/** return number of rrs in an rrset */
static size_t
rrset_get_count(struct ub_packed_rrset_key* rrset)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        if(!d) return 0;
        return d->count;
}

/** return if nsec3 RR has unknown flags */
static int
nsec3_unknown_flags(struct ub_packed_rrset_key* rrset, int r)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        log_assert(d && r < (int)d->count);
        if(d->rr_len[r] < 2+2)
                return 0; /* malformed */
        return (int)(d->rr_data[r][2+1] & NSEC3_UNKNOWN_FLAGS);
}

int
nsec3_has_optout(struct ub_packed_rrset_key* rrset, int r)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        log_assert(d && r < (int)d->count);
        if(d->rr_len[r] < 2+2)
                return 0; /* malformed */
        return (int)(d->rr_data[r][2+1] & NSEC3_OPTOUT);
}

/** return nsec3 RR algorithm */
static int
nsec3_get_algo(struct ub_packed_rrset_key* rrset, int r)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        log_assert(d && r < (int)d->count);
        if(d->rr_len[r] < 2+1)
                return 0; /* malformed */
        return (int)(d->rr_data[r][2+0]);
}

/** return if nsec3 RR has known algorithm */
static int
nsec3_known_algo(struct ub_packed_rrset_key* rrset, int r)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        log_assert(d && r < (int)d->count);
        if(d->rr_len[r] < 2+1)
                return 0; /* malformed */
        switch(d->rr_data[r][2+0]) {
                case NSEC3_HASH_SHA1:
                        return 1;
        }
        return 0;
}

/** return nsec3 RR iteration count */
static size_t
nsec3_get_iter(struct ub_packed_rrset_key* rrset, int r)
{
        uint16_t i;
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        log_assert(d && r < (int)d->count);
        if(d->rr_len[r] < 2+4)
                return 0; /* malformed */
        memmove(&i, d->rr_data[r]+2+2, sizeof(i));
        i = ntohs(i);
        return (size_t)i;
}

/** return nsec3 RR salt */
static int
nsec3_get_salt(struct ub_packed_rrset_key* rrset, int r,
        uint8_t** salt, size_t* saltlen)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        log_assert(d && r < (int)d->count);
        if(d->rr_len[r] < 2+5) {
                *salt = 0;
                *saltlen = 0;
                return 0; /* malformed */
        }
        *saltlen = (size_t)d->rr_data[r][2+4];
        if(d->rr_len[r] < 2+5+(size_t)*saltlen) {
                *salt = 0;
                *saltlen = 0;
                return 0; /* malformed */
        }
        *salt = d->rr_data[r]+2+5;
        return 1;
}

int nsec3_get_params(struct ub_packed_rrset_key* rrset, int r,
        int* algo, size_t* iter, uint8_t** salt, size_t* saltlen)
{
        if(!nsec3_known_algo(rrset, r) || nsec3_unknown_flags(rrset, r))
                return 0;
        if(!nsec3_get_salt(rrset, r, salt, saltlen))
                return 0;
        *algo = nsec3_get_algo(rrset, r);
        *iter = nsec3_get_iter(rrset, r);
        return 1;
}

int
nsec3_get_nextowner(struct ub_packed_rrset_key* rrset, int r,
        uint8_t** next, size_t* nextlen)
{
        size_t saltlen;
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        log_assert(d && r < (int)d->count);
        if(d->rr_len[r] < 2+5) {
                *next = 0;
                *nextlen = 0;
                return 0; /* malformed */
        }
        saltlen = (size_t)d->rr_data[r][2+4];
        if(d->rr_len[r] < 2+5+saltlen+1) {
                *next = 0;
                *nextlen = 0;
                return 0; /* malformed */
        }
        *nextlen = (size_t)d->rr_data[r][2+5+saltlen];
        if(d->rr_len[r] < 2+5+saltlen+1+*nextlen) {
                *next = 0;
                *nextlen = 0;
                return 0; /* malformed */
        }
        *next = d->rr_data[r]+2+5+saltlen+1;
        return 1;
}

size_t nsec3_hash_to_b32(uint8_t* hash, size_t hashlen, uint8_t* zone,
        size_t zonelen, uint8_t* buf, size_t max)
{
        /* write b32 of name, leave one for length */
        int ret;
        if(max < hashlen*2+1) /* quick approx of b32, as if hexb16 */
                return 0;
        ret = sldns_b32_ntop_extended_hex(hash, hashlen, (char*)buf+1, max-1);
        if(ret < 1) 
                return 0;
        buf[0] = (uint8_t)ret; /* length of b32 label */
        ret++;
        if(max - ret < zonelen)
                return 0;
        memmove(buf+ret, zone, zonelen);
        return zonelen+(size_t)ret;
}

size_t nsec3_get_nextowner_b32(struct ub_packed_rrset_key* rrset, int r,
        uint8_t* buf, size_t max)
{
        uint8_t* nm, *zone;
        size_t nmlen, zonelen;
        if(!nsec3_get_nextowner(rrset, r, &nm, &nmlen))
                return 0;
        /* append zone name; the owner name must be <b32>.zone */
        zone = rrset->rk.dname;
        zonelen = rrset->rk.dname_len;
        dname_remove_label(&zone, &zonelen);
        return nsec3_hash_to_b32(nm, nmlen, zone, zonelen, buf, max);
}

int
nsec3_has_type(struct ub_packed_rrset_key* rrset, int r, uint16_t type)
{
        uint8_t* bitmap;
        size_t bitlen, skiplen;
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        log_assert(d && r < (int)d->count);
        skiplen = 2+4;
        /* skip salt */
        if(d->rr_len[r] < skiplen+1)
                return 0; /* malformed, too short */
        skiplen += 1+(size_t)d->rr_data[r][skiplen]; 
        /* skip next hashed owner */
        if(d->rr_len[r] < skiplen+1)
                return 0; /* malformed, too short */
        skiplen += 1+(size_t)d->rr_data[r][skiplen]; 
        if(d->rr_len[r] < skiplen)
                return 0; /* malformed, too short */
        bitlen = d->rr_len[r] - skiplen;
        bitmap = d->rr_data[r]+skiplen;
        return nsecbitmap_has_type_rdata(bitmap, bitlen, type);
}
        
/** 
 * Iterate through NSEC3 list, per RR 
 * This routine gives the next RR in the list (or sets rrset null). 
 * Usage:
 *
 * size_t rrsetnum;
 * int rrnum;
 * struct ub_packed_rrset_key* rrset;
 * for(rrset=filter_first(filter, &rrsetnum, &rrnum); rrset; 
 *      rrset=filter_next(filter, &rrsetnum, &rrnum))
 *              do_stuff;
 * 
 * Also filters out 
 *      o unknown flag NSEC3s
 *      o unknown algorithm NSEC3s.
 * @param filter: nsec3 filter structure.
 * @param rrsetnum: in/out rrset number to look at.
 * @param rrnum: in/out rr number in rrset to look at.
 * @returns ptr to the next rrset (or NULL at end).
 */
static struct ub_packed_rrset_key*
filter_next(struct nsec3_filter* filter, size_t* rrsetnum, int* rrnum)
{
        size_t i;
        int r;
        uint8_t* nm;
        size_t nmlen;
        if(!filter->zone) /* empty list */
                return NULL;
        for(i=*rrsetnum; i<filter->num; i++) {
                /* see if RRset qualifies */
                if(ntohs(filter->list[i]->rk.type) != LDNS_RR_TYPE_NSEC3 ||
                        ntohs(filter->list[i]->rk.rrset_class) != 
                        filter->fclass) 
                        continue;
                /* check RRset zone */
                nm = filter->list[i]->rk.dname;
                nmlen = filter->list[i]->rk.dname_len;
                dname_remove_label(&nm, &nmlen);
                if(query_dname_compare(nm, filter->zone) != 0)
                        continue;
                if(i == *rrsetnum)
                        r = (*rrnum) + 1; /* continue at next RR */
                else    r = 0;          /* new RRset start at first RR */
                for(; r < (int)rrset_get_count(filter->list[i]); r++) {
                        /* skip unknown flags, algo */
                        if(nsec3_unknown_flags(filter->list[i], r) ||
                                !nsec3_known_algo(filter->list[i], r))
                                continue;
                        /* this one is a good target */
                        *rrsetnum = i;
                        *rrnum = r;
                        return filter->list[i];
                }
        }
        return NULL;
}

/**
 * Start iterating over NSEC3 records.
 * @param filter: the filter structure, must have been filter_init-ed.
 * @param rrsetnum: can be undefined on call, initialised.
 * @param rrnum: can be undefined on call, initialised.
 * @return first rrset of an NSEC3, together with rrnum this points to
 *      the first RR to examine. Is NULL on empty list.
 */
static struct ub_packed_rrset_key*
filter_first(struct nsec3_filter* filter, size_t* rrsetnum, int* rrnum)
{
        *rrsetnum = 0;
        *rrnum = -1;
        return filter_next(filter, rrsetnum, rrnum);
}

/** see if at least one RR is known (flags, algo) */
static int
nsec3_rrset_has_known(struct ub_packed_rrset_key* s)
{
        int r;
        for(r=0; r < (int)rrset_get_count(s); r++) {
                if(!nsec3_unknown_flags(s, r) && nsec3_known_algo(s, r))
                        return 1;
        }
        return 0;
}

/** 
 * Initialize the filter structure.
 * Finds the zone by looking at available NSEC3 records and best match.
 *      (skips the unknown flag and unknown algo NSEC3s).
 *
 * @param filter: nsec3 filter structure.
 * @param list: list of rrsets, an array of them.
 * @param num: number of rrsets in list.
 * @param qinfo: 
 *      query name to match a zone for.
 *      query type (if DS a higher zone must be chosen)
 *      qclass, to filter NSEC3s with.
 */
static void
filter_init(struct nsec3_filter* filter, struct ub_packed_rrset_key** list,
        size_t num, struct query_info* qinfo)
{
        size_t i;
        uint8_t* nm;
        size_t nmlen;
        filter->zone = NULL;
        filter->zone_len = 0;
        filter->list = list;
        filter->num = num;
        filter->fclass = qinfo->qclass;
        for(i=0; i<num; i++) {
                /* ignore other stuff in the list */
                if(ntohs(list[i]->rk.type) != LDNS_RR_TYPE_NSEC3 ||
                        ntohs(list[i]->rk.rrset_class) != qinfo->qclass) 
                        continue;
                /* skip unknown flags, algo */
                if(!nsec3_rrset_has_known(list[i]))
                        continue;

                /* since NSEC3s are base32.zonename, we can find the zone
                 * name by stripping off the first label of the record */
                nm = list[i]->rk.dname;
                nmlen = list[i]->rk.dname_len;
                dname_remove_label(&nm, &nmlen);
                /* if we find a domain that can prove about the qname,
                 * and if this domain is closer to the qname */
                if(dname_subdomain_c(qinfo->qname, nm) && (!filter->zone ||
                        dname_subdomain_c(nm, filter->zone))) {
                        /* for a type DS do not accept a zone equal to qname*/
                        if(qinfo->qtype == LDNS_RR_TYPE_DS && 
                                query_dname_compare(qinfo->qname, nm) == 0 &&
                                !dname_is_root(qinfo->qname))
                                continue;
                        filter->zone = nm;
                        filter->zone_len = nmlen;
                }
        }
}

/**
 * Find max iteration count using config settings and key size
 * @param ve: validator environment with iteration count config settings.
 * @param bits: key size
 * @return max iteration count
 */
static size_t
get_max_iter(struct val_env* ve, size_t bits)
{
        int i;
        log_assert(ve->nsec3_keyiter_count > 0);
        /* round up to nearest config keysize, linear search, keep it small */
        for(i=0; i<ve->nsec3_keyiter_count; i++) {
                if(bits <= ve->nsec3_keysize[i])
                        return ve->nsec3_maxiter[i];
        }
        /* else, use value for biggest key */
        return ve->nsec3_maxiter[ve->nsec3_keyiter_count-1];
}

/** 
 * Determine if any of the NSEC3 rrs iteration count is too high, from key.
 * @param ve: validator environment with iteration count config settings.
 * @param filter: what NSEC3s to loop over.
 * @param kkey: key entry used for verification; used for iteration counts.
 * @return 1 if some nsec3s are above the max iteration count.
 */
static int
nsec3_iteration_count_high(struct val_env* ve, struct nsec3_filter* filter, 
        struct key_entry_key* kkey)
{
        size_t rrsetnum;
        int rrnum;
        struct ub_packed_rrset_key* rrset;
        /* first determine the max number of iterations */
        size_t bits = key_entry_keysize(kkey);
        size_t max_iter = get_max_iter(ve, bits);
        verbose(VERB_ALGO, "nsec3: keysize %d bits, max iterations %d",
                (int)bits, (int)max_iter);

        for(rrset=filter_first(filter, &rrsetnum, &rrnum); rrset; 
                rrset=filter_next(filter, &rrsetnum, &rrnum)) {
                if(nsec3_get_iter(rrset, rrnum) > max_iter)
                        return 1;
        }
        return 0;
}

/* nsec3_cache_compare for rbtree */
int
nsec3_hash_cmp(const void* c1, const void* c2) 
{
        struct nsec3_cached_hash* h1 = (struct nsec3_cached_hash*)c1;
        struct nsec3_cached_hash* h2 = (struct nsec3_cached_hash*)c2;
        uint8_t* s1, *s2;
        size_t s1len, s2len;
        int c = query_dname_compare(h1->dname, h2->dname);
        if(c != 0)
                return c;
        /* compare parameters */
        /* if both malformed, its equal, robustness */
        if(nsec3_get_algo(h1->nsec3, h1->rr) !=
                nsec3_get_algo(h2->nsec3, h2->rr)) {
                if(nsec3_get_algo(h1->nsec3, h1->rr) <
                        nsec3_get_algo(h2->nsec3, h2->rr))
                        return -1;
                return 1;
        }
        if(nsec3_get_iter(h1->nsec3, h1->rr) !=
                nsec3_get_iter(h2->nsec3, h2->rr)) {
                if(nsec3_get_iter(h1->nsec3, h1->rr) <
                        nsec3_get_iter(h2->nsec3, h2->rr))
                        return -1;
                return 1;
        }
        (void)nsec3_get_salt(h1->nsec3, h1->rr, &s1, &s1len);
        (void)nsec3_get_salt(h2->nsec3, h2->rr, &s2, &s2len);
        if(s1len == 0 && s2len == 0)
                return 0;
        if(!s1) return -1;
        if(!s2) return 1;
        if(s1len != s2len) {
                if(s1len < s2len)
                        return -1;
                return 1;
        }
        return memcmp(s1, s2, s1len);
}

int
nsec3_cache_table_init(struct nsec3_cache_table* ct, struct regional* region)
{
        if(ct->ct) return 1;
        ct->ct = (rbtree_type*)regional_alloc(region, sizeof(*ct->ct));
        if(!ct->ct) return 0;
        ct->region = region;
        rbtree_init(ct->ct, &nsec3_hash_cmp);
        return 1;
}

size_t
nsec3_get_hashed(sldns_buffer* buf, uint8_t* nm, size_t nmlen, int algo, 
        size_t iter, uint8_t* salt, size_t saltlen, uint8_t* res, size_t max)
{
        size_t i, hash_len;
        /* prepare buffer for first iteration */
        sldns_buffer_clear(buf);
        sldns_buffer_write(buf, nm, nmlen);
        query_dname_tolower(sldns_buffer_begin(buf));
        if(saltlen != 0)
                sldns_buffer_write(buf, salt, saltlen);
        sldns_buffer_flip(buf);
        hash_len = nsec3_hash_algo_size_supported(algo);
        if(hash_len == 0) {
                log_err("nsec3 hash of unknown algo %d", algo);
                return 0;
        }
        if(hash_len > max)
                return 0;
        if(!secalgo_nsec3_hash(algo, (unsigned char*)sldns_buffer_begin(buf),
                sldns_buffer_limit(buf), (unsigned char*)res))
                return 0;
        for(i=0; i<iter; i++) {
                sldns_buffer_clear(buf);
                sldns_buffer_write(buf, res, hash_len);
                if(saltlen != 0)
                        sldns_buffer_write(buf, salt, saltlen);
                sldns_buffer_flip(buf);
                if(!secalgo_nsec3_hash(algo,
                        (unsigned char*)sldns_buffer_begin(buf),
                        sldns_buffer_limit(buf), (unsigned char*)res))
                        return 0;
        }
        return hash_len;
}

/** perform hash of name */
static int
nsec3_calc_hash(struct regional* region, sldns_buffer* buf, 
        struct nsec3_cached_hash* c)
{
        int algo = nsec3_get_algo(c->nsec3, c->rr);
        size_t iter = nsec3_get_iter(c->nsec3, c->rr);
        uint8_t* salt;
        size_t saltlen, i;
        if(!nsec3_get_salt(c->nsec3, c->rr, &salt, &saltlen))
                return -1;
        /* prepare buffer for first iteration */
        sldns_buffer_clear(buf);
        sldns_buffer_write(buf, c->dname, c->dname_len);
        query_dname_tolower(sldns_buffer_begin(buf));
        sldns_buffer_write(buf, salt, saltlen);
        sldns_buffer_flip(buf);
        c->hash_len = nsec3_hash_algo_size_supported(algo);
        if(c->hash_len == 0) {
                log_err("nsec3 hash of unknown algo %d", algo);
                return -1;
        }
        c->hash = (uint8_t*)regional_alloc(region, c->hash_len);
        if(!c->hash)
                return 0;
        (void)secalgo_nsec3_hash(algo, (unsigned char*)sldns_buffer_begin(buf),
                sldns_buffer_limit(buf), (unsigned char*)c->hash);
        for(i=0; i<iter; i++) {
                sldns_buffer_clear(buf);
                sldns_buffer_write(buf, c->hash, c->hash_len);
                sldns_buffer_write(buf, salt, saltlen);
                sldns_buffer_flip(buf);
                (void)secalgo_nsec3_hash(algo,
                        (unsigned char*)sldns_buffer_begin(buf),
                        sldns_buffer_limit(buf), (unsigned char*)c->hash);
        }
        return 1;
}

/** perform b32 encoding of hash */
static int
nsec3_calc_b32(struct regional* region, sldns_buffer* buf, 
        struct nsec3_cached_hash* c)
{
        int r;
        sldns_buffer_clear(buf);
        r = sldns_b32_ntop_extended_hex(c->hash, c->hash_len,
                (char*)sldns_buffer_begin(buf), sldns_buffer_limit(buf));
        if(r < 1) {
                log_err("b32_ntop_extended_hex: error in encoding: %d", r);
                return 0;
        }
        c->b32_len = (size_t)r;
        c->b32 = regional_alloc_init(region, sldns_buffer_begin(buf), 
                c->b32_len);
        if(!c->b32)
                return 0;
        return 1;
}

int
nsec3_hash_name(rbtree_type* table, struct regional* region, sldns_buffer* buf,
        struct ub_packed_rrset_key* nsec3, int rr, uint8_t* dname, 
        size_t dname_len, struct nsec3_cached_hash** hash)
{
        struct nsec3_cached_hash* c;
        struct nsec3_cached_hash looki;
#ifdef UNBOUND_DEBUG
        rbnode_type* n;
#endif
        int r;
        looki.node.key = &looki;
        looki.nsec3 = nsec3;
        looki.rr = rr;
        looki.dname = dname;
        looki.dname_len = dname_len;
        /* lookup first in cache */
        c = (struct nsec3_cached_hash*)rbtree_search(table, &looki);
        if(c) {
                *hash = c;
                return 2;
        }
        /* create a new entry */
        c = (struct nsec3_cached_hash*)regional_alloc(region, sizeof(*c));
        if(!c) return 0;
        c->node.key = c;
        c->nsec3 = nsec3;
        c->rr = rr;
        c->dname = dname;
        c->dname_len = dname_len;
        r = nsec3_calc_hash(region, buf, c);
        if(r != 1)
                return r;  /* returns -1 or 0 */
        r = nsec3_calc_b32(region, buf, c);
        if(r != 1)
                return r;  /* returns 0 */
#ifdef UNBOUND_DEBUG
        n =
#else
        (void)
#endif
        rbtree_insert(table, &c->node);
        log_assert(n); /* cannot be duplicate, just did lookup */
        *hash = c;
        return 1;
}

/**
 * compare a label lowercased
 */
static int
label_compare_lower(uint8_t* lab1, uint8_t* lab2, size_t lablen)
{
        size_t i;
        for(i=0; i<lablen; i++) {
                if(tolower((unsigned char)*lab1) != tolower((unsigned char)*lab2)) {
                        if(tolower((unsigned char)*lab1) < tolower((unsigned char)*lab2))
                                return -1;
                        return 1;
                }
                lab1++;
                lab2++;
        }
        return 0;
}

/**
 * Compare a hashed name with the owner name of an NSEC3 RRset.
 * @param flt: filter with zone name.
 * @param hash: the hashed name.
 * @param s: rrset with owner name.
 * @return true if matches exactly, false if not.
 */
static int
nsec3_hash_matches_owner(struct nsec3_filter* flt, 
        struct nsec3_cached_hash* hash, struct ub_packed_rrset_key* s)
{
        uint8_t* nm = s->rk.dname;
        if(!hash) return 0; /* please clang */
        /* compare, does hash of name based on params in this NSEC3
         * match the owner name of this NSEC3? 
         * name must be: <hashlength>base32 . zone name 
         * so; first label must not be root label (not zero length),
         * and match the b32 encoded hash length, 
         * and the label content match the b32 encoded hash
         * and the rest must be the zone name.
         */
        if(hash->b32_len != 0 && (size_t)nm[0] == hash->b32_len &&
                label_compare_lower(nm+1, hash->b32, hash->b32_len) == 0 &&
                query_dname_compare(nm+(size_t)nm[0]+1, flt->zone) == 0) {
                return 1;
        }
        return 0;
}

/**
 * Find matching NSEC3
 * Find the NSEC3Record that matches a hash of a name.
 * @param env: module environment with temporary region and buffer.
 * @param flt: the NSEC3 RR filter, contains zone name and RRs.
 * @param ct: cached hashes table.
 * @param nm: name to look for.
 * @param nmlen: length of name.
 * @param rrset: nsec3 that matches is returned here.
 * @param rr: rr number in nsec3 rrset that matches.
 * @param calculations: current hash calculations.
 * @return true if a matching NSEC3 is found, false if not.
 */
static int
find_matching_nsec3(struct module_env* env, struct nsec3_filter* flt,
        struct nsec3_cache_table* ct, uint8_t* nm, size_t nmlen,
        struct ub_packed_rrset_key** rrset, int* rr,
        int* calculations)
{
        size_t i_rs;
        int i_rr;
        struct ub_packed_rrset_key* s;
        struct nsec3_cached_hash* hash = NULL;
        int r;
        int calc_errors = 0;

        /* this loop skips other-zone and unknown NSEC3s, also non-NSEC3 RRs */
        for(s=filter_first(flt, &i_rs, &i_rr); s; 
                s=filter_next(flt, &i_rs, &i_rr)) {
                /* check if we are allowed more calculations */
                if(*calculations >= MAX_NSEC3_CALCULATIONS) {
                        if(calc_errors == *calculations) {
                                *calculations = MAX_NSEC3_ERRORS;
                        }
                        break;
                }
                /* get name hashed for this NSEC3 RR */
                r = nsec3_hash_name(ct->ct, ct->region, env->scratch_buffer,
                        s, i_rr, nm, nmlen, &hash);
                if(r == 0) {
                        log_err("nsec3: malloc failure");
                        break; /* alloc failure */
                } else if(r < 0) {
                        /* malformed NSEC3 */
                        calc_errors++;
                        (*calculations)++;
                        continue;
                } else {
                        if(r == 1) (*calculations)++;
                        if(nsec3_hash_matches_owner(flt, hash, s)) {
                                *rrset = s; /* rrset with this name */
                                *rr = i_rr; /* matches hash with these parameters */
                                return 1;
                        }
                }
        }
        *rrset = NULL;
        *rr = 0;
        return 0;
}

int
nsec3_covers(uint8_t* zone, struct nsec3_cached_hash* hash,
        struct ub_packed_rrset_key* rrset, int rr, sldns_buffer* buf)
{
        uint8_t* next, *owner;
        size_t nextlen;
        int len;
        if(!nsec3_get_nextowner(rrset, rr, &next, &nextlen))
                return 0; /* malformed RR proves nothing */

        if(!hash) return 0; /* please clang */
        /* check the owner name is a hashed value . apex
         * base32 encoded values must have equal length. 
         * hash_value and next hash value must have equal length. */
        if(nextlen != hash->hash_len || hash->hash_len==0||hash->b32_len==0|| 
                (size_t)*rrset->rk.dname != hash->b32_len ||
                query_dname_compare(rrset->rk.dname+1+
                        (size_t)*rrset->rk.dname, zone) != 0)
                return 0; /* bad lengths or owner name */

        /* This is the "normal case: owner < next and owner < hash < next */
        if(label_compare_lower(rrset->rk.dname+1, hash->b32, 
                hash->b32_len) < 0 && 
                memcmp(hash->hash, next, nextlen) < 0)
                return 1;

        /* convert owner name from text to binary */
        sldns_buffer_clear(buf);
        owner = sldns_buffer_begin(buf);
        len = sldns_b32_pton_extended_hex((char*)rrset->rk.dname+1, 
                hash->b32_len, owner, sldns_buffer_limit(buf));
        if(len<1)
                return 0; /* bad owner name in some way */
        if((size_t)len != hash->hash_len || (size_t)len != nextlen)
                return 0; /* wrong length */

        /* this is the end of zone case: next <= owner && 
         *      (hash > owner || hash < next) 
         * this also covers the only-apex case of next==owner.
         */
        if(memcmp(next, owner, nextlen) <= 0 &&
                ( memcmp(hash->hash, owner, nextlen) > 0 ||
                  memcmp(hash->hash, next, nextlen) < 0)) {
                return 1;
        }
        return 0;
}

/**
 * findCoveringNSEC3
 * Given a name, find a covering NSEC3 from among a list of NSEC3s.
 *
 * @param env: module environment with temporary region and buffer.
 * @param flt: the NSEC3 RR filter, contains zone name and RRs.
 * @param ct: cached hashes table.
 * @param nm: name to check if covered.
 * @param nmlen: length of name.
 * @param rrset: covering NSEC3 rrset is returned here.
 * @param rr: rr of cover is returned here.
 * @param calculations: current hash calculations.
 * @return true if a covering NSEC3 is found, false if not.
 */
static int
find_covering_nsec3(struct module_env* env, struct nsec3_filter* flt,
        struct nsec3_cache_table* ct, uint8_t* nm, size_t nmlen,
        struct ub_packed_rrset_key** rrset, int* rr,
        int* calculations)
{
        size_t i_rs;
        int i_rr;
        struct ub_packed_rrset_key* s;
        struct nsec3_cached_hash* hash = NULL;
        int r;
        int calc_errors = 0;

        /* this loop skips other-zone and unknown NSEC3s, also non-NSEC3 RRs */
        for(s=filter_first(flt, &i_rs, &i_rr); s; 
                s=filter_next(flt, &i_rs, &i_rr)) {
                /* check if we are allowed more calculations */
                if(*calculations >= MAX_NSEC3_CALCULATIONS) {
                        if(calc_errors == *calculations) {
                                *calculations = MAX_NSEC3_ERRORS;
                        }
                        break;
                }
                /* get name hashed for this NSEC3 RR */
                r = nsec3_hash_name(ct->ct, ct->region, env->scratch_buffer,
                        s, i_rr, nm, nmlen, &hash);
                if(r == 0) {
                        log_err("nsec3: malloc failure");
                        break; /* alloc failure */
                } else if(r < 0) {
                        /* malformed NSEC3 */
                        calc_errors++;
                        (*calculations)++;
                        continue;
                } else {
                        if(r == 1) (*calculations)++;
                        if(nsec3_covers(flt->zone, hash, s, i_rr,
                                env->scratch_buffer)) {
                                *rrset = s; /* rrset with this name */
                                *rr = i_rr; /* covers hash with these parameters */
                                return 1;
                        }
                }
        }
        *rrset = NULL;
        *rr = 0;
        return 0;
}

/**
 * findClosestEncloser
 * Given a name and a list of NSEC3s, find the candidate closest encloser.
 * This will be the first ancestor of 'name' (including itself) to have a
 * matching NSEC3 RR.
 * @param env: module environment with temporary region and buffer.
 * @param flt: the NSEC3 RR filter, contains zone name and RRs.
 * @param ct: cached hashes table.
 * @param qinfo: query that is verified for.
 * @param ce: closest encloser information is returned in here.
 * @param calculations: current hash calculations.
 * @return true if a closest encloser candidate is found, false if not.
 */
static int
nsec3_find_closest_encloser(struct module_env* env, struct nsec3_filter* flt,
        struct nsec3_cache_table* ct, struct query_info* qinfo,
        struct ce_response* ce, int* calculations)
{
        uint8_t* nm = qinfo->qname;
        size_t nmlen = qinfo->qname_len;

        /* This scans from longest name to shortest, so the first match 
         * we find is the only viable candidate. */

        /* (David:) FIXME: modify so that the NSEC3 matching the zone apex need 
         * not be present. (Mark Andrews idea).
         * (Wouter:) But make sure you check for DNAME bit in zone apex,
         * if the NSEC3 you find is the only NSEC3 in the zone, then this
         * may be the case. */

        while(dname_subdomain_c(nm, flt->zone)) {
                if(*calculations >= MAX_NSEC3_CALCULATIONS ||
                        *calculations == MAX_NSEC3_ERRORS) {
                        return 0;
                }
                if(find_matching_nsec3(env, flt, ct, nm, nmlen, 
                        &ce->ce_rrset, &ce->ce_rr, calculations)) {
                        ce->ce = nm;
                        ce->ce_len = nmlen;
                        return 1;
                }
                dname_remove_label(&nm, &nmlen);
        }
        return 0;
}

/**
 * Given a qname and its proven closest encloser, calculate the "next
 * closest" name. Basically, this is the name that is one label longer than
 * the closest encloser that is still a subdomain of qname.
 *
 * @param qname: query name.
 * @param qnamelen: length of qname.
 * @param ce: closest encloser
 * @param nm: result name.
 * @param nmlen: length of nm.
 */
static void
next_closer(uint8_t* qname, size_t qnamelen, uint8_t* ce, 
        uint8_t** nm, size_t* nmlen)
{
        int strip = dname_count_labels(qname) - dname_count_labels(ce) -1;
        *nm = qname;
        *nmlen = qnamelen;
        if(strip>0)
                dname_remove_labels(nm, nmlen, strip);
}

/**
 * proveClosestEncloser
 * Given a List of nsec3 RRs, find and prove the closest encloser to qname.
 * @param env: module environment with temporary region and buffer.
 * @param flt: the NSEC3 RR filter, contains zone name and RRs.
 * @param ct: cached hashes table.
 * @param qinfo: query that is verified for.
 * @param prove_does_not_exist: If true, then if the closest encloser 
 *      turns out to be qname, then null is returned.
 *      If set true, and the return value is true, then you can be 
 *      certain that the ce.nc_rrset and ce.nc_rr are set properly.
 * @param ce: closest encloser information is returned in here.
 * @param calculations: pointer to the current NSEC3 hash calculations.
 * @return bogus if no closest encloser could be proven.
 *      secure if a closest encloser could be proven, ce is set.
 *      insecure if the closest-encloser candidate turns out to prove
 *              that an insecure delegation exists above the qname.
 *      unchecked if no more hash calculations are allowed at this point.
 */
static enum sec_status
nsec3_prove_closest_encloser(struct module_env* env, struct nsec3_filter* flt,
        struct nsec3_cache_table* ct, struct query_info* qinfo,
        int prove_does_not_exist, struct ce_response* ce, int* calculations)
{
        uint8_t* nc;
        size_t nc_len;
        /* robust: clean out ce, in case it gets abused later */
        memset(ce, 0, sizeof(*ce));

        if(!nsec3_find_closest_encloser(env, flt, ct, qinfo, ce, calculations)) {
                if(*calculations == MAX_NSEC3_ERRORS) {
                        verbose(VERB_ALGO, "nsec3 proveClosestEncloser: could "
                                "not find a candidate for the closest "
                                "encloser; all attempted hash calculations "
                                "were erroneous; bogus");
                        return sec_status_bogus;
                } else if(*calculations >= MAX_NSEC3_CALCULATIONS) {
                        verbose(VERB_ALGO, "nsec3 proveClosestEncloser: could "
                                "not find a candidate for the closest "
                                "encloser; reached MAX_NSEC3_CALCULATIONS "
                                "(%d); unchecked still",
                                MAX_NSEC3_CALCULATIONS);
                        return sec_status_unchecked;
                }
                verbose(VERB_ALGO, "nsec3 proveClosestEncloser: could "
                        "not find a candidate for the closest encloser.");
                return sec_status_bogus;
        }
        log_nametypeclass(VERB_ALGO, "ce candidate", ce->ce, 0, 0);

        if(query_dname_compare(ce->ce, qinfo->qname) == 0) {
                if(prove_does_not_exist) {
                        verbose(VERB_ALGO, "nsec3 proveClosestEncloser: "
                                "proved that qname existed, bad");
                        return sec_status_bogus;
                }
                /* otherwise, we need to nothing else to prove that qname 
                 * is its own closest encloser. */
                return sec_status_secure;
        }

        /* If the closest encloser is actually a delegation, then the 
         * response should have been a referral. If it is a DNAME, then 
         * it should have been a DNAME response. */
        if(nsec3_has_type(ce->ce_rrset, ce->ce_rr, LDNS_RR_TYPE_NS) &&
                !nsec3_has_type(ce->ce_rrset, ce->ce_rr, LDNS_RR_TYPE_SOA)) {
                if(!nsec3_has_type(ce->ce_rrset, ce->ce_rr, LDNS_RR_TYPE_DS)) {
                        verbose(VERB_ALGO, "nsec3 proveClosestEncloser: "
                                "closest encloser is insecure delegation");
                        return sec_status_insecure;
                }
                verbose(VERB_ALGO, "nsec3 proveClosestEncloser: closest "
                        "encloser was a delegation, bad");
                return sec_status_bogus;
        }
        if(nsec3_has_type(ce->ce_rrset, ce->ce_rr, LDNS_RR_TYPE_DNAME)) {
                verbose(VERB_ALGO, "nsec3 proveClosestEncloser: closest "
                        "encloser was a DNAME, bad");
                return sec_status_bogus;
        }
        
        /* Otherwise, we need to show that the next closer name is covered. */
        next_closer(qinfo->qname, qinfo->qname_len, ce->ce, &nc, &nc_len);
        if(!find_covering_nsec3(env, flt, ct, nc, nc_len, 
                &ce->nc_rrset, &ce->nc_rr, calculations)) {
                if(*calculations == MAX_NSEC3_ERRORS) {
                        verbose(VERB_ALGO, "nsec3: Could not find proof that the "
                                "candidate encloser was the closest encloser; "
                                "all attempted hash calculations were "
                                "erroneous; bogus");
                        return sec_status_bogus;
                } else if(*calculations >= MAX_NSEC3_CALCULATIONS) {
                        verbose(VERB_ALGO, "nsec3: Could not find proof that the "
                                "candidate encloser was the closest encloser; "
                                "reached MAX_NSEC3_CALCULATIONS (%d); "
                                "unchecked still",
                                MAX_NSEC3_CALCULATIONS);
                        return sec_status_unchecked;
                }
                verbose(VERB_ALGO, "nsec3: Could not find proof that the "
                        "candidate encloser was the closest encloser");
                return sec_status_bogus;
        }
        return sec_status_secure;
}

/** allocate a wildcard for the closest encloser */
static uint8_t*
nsec3_ce_wildcard(struct regional* region, uint8_t* ce, size_t celen,
        size_t* len)
{
        uint8_t* nm;
        if(celen > LDNS_MAX_DOMAINLEN - 2)
                return 0; /* too long */
        nm = (uint8_t*)regional_alloc(region, celen+2);
        if(!nm) {
                log_err("nsec3 wildcard: out of memory");
                return 0; /* alloc failure */
        }
        nm[0] = 1;
        nm[1] = (uint8_t)'*'; /* wildcard label */
        memmove(nm+2, ce, celen);
        *len = celen+2;
        return nm;
}

/** Do the name error proof */
static enum sec_status
nsec3_do_prove_nameerror(struct module_env* env, struct nsec3_filter* flt,
        struct nsec3_cache_table* ct, struct query_info* qinfo, int* calc)
{
        struct ce_response ce;
        uint8_t* wc;
        size_t wclen;
        struct ub_packed_rrset_key* wc_rrset;
        int wc_rr;
        enum sec_status sec;

        /* First locate and prove the closest encloser to qname. We will 
         * use the variant that fails if the closest encloser turns out 
         * to be qname. */
        sec = nsec3_prove_closest_encloser(env, flt, ct, qinfo, 1, &ce, calc);
        if(sec != sec_status_secure) {
                if(sec == sec_status_bogus)
                        verbose(VERB_ALGO, "nsec3 nameerror proof: failed "
                                "to prove a closest encloser");
                else if(sec == sec_status_unchecked)
                        verbose(VERB_ALGO, "nsec3 nameerror proof: will "
                                "continue proving closest encloser after "
                                "suspend");
                else    verbose(VERB_ALGO, "nsec3 nameerror proof: closest "
                                "nsec3 is an insecure delegation");
                return sec;
        }
        log_nametypeclass(VERB_ALGO, "nsec3 nameerror: proven ce=", ce.ce,0,0);

        /* At this point, we know that qname does not exist. Now we need 
         * to prove that the wildcard does not exist. */
        log_assert(ce.ce);
        wc = nsec3_ce_wildcard(ct->region, ce.ce, ce.ce_len, &wclen);
        if(!wc) {
                verbose(VERB_ALGO, "nsec3 nameerror proof: could not prove "
                        "that the applicable wildcard did not exist.");
                return sec_status_bogus;
        }
        if(!find_covering_nsec3(env, flt, ct, wc, wclen, &wc_rrset, &wc_rr, calc)) {
                if(*calc == MAX_NSEC3_ERRORS) {
                        verbose(VERB_ALGO, "nsec3 nameerror proof: could not prove "
                                "that the applicable wildcard did not exist; "
                                "all attempted hash calculations were "
                                "erroneous; bogus");
                        return sec_status_bogus;
                } else if(*calc >= MAX_NSEC3_CALCULATIONS) {
                        verbose(VERB_ALGO, "nsec3 nameerror proof: could not prove "
                                "that the applicable wildcard did not exist; "
                                "reached MAX_NSEC3_CALCULATIONS (%d); "
                                "unchecked still",
                                MAX_NSEC3_CALCULATIONS);
                        return sec_status_unchecked;
                }
                verbose(VERB_ALGO, "nsec3 nameerror proof: could not prove "
                        "that the applicable wildcard did not exist.");
                return sec_status_bogus;
        }

        if(ce.nc_rrset && nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
                verbose(VERB_ALGO, "nsec3 nameerror proof: nc has optout");
                return sec_status_insecure;
        }
        return sec_status_secure;
}

enum sec_status
nsec3_prove_nameerror(struct module_env* env, struct val_env* ve,
        struct ub_packed_rrset_key** list, size_t num,
        struct query_info* qinfo, struct key_entry_key* kkey,
        struct nsec3_cache_table* ct, int* calc)
{
        struct nsec3_filter flt;

        if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
                return sec_status_bogus; /* no valid NSEC3s, bogus */
        filter_init(&flt, list, num, qinfo); /* init RR iterator */
        if(!flt.zone)
                return sec_status_bogus; /* no RRs */
        if(nsec3_iteration_count_high(ve, &flt, kkey))
                return sec_status_insecure; /* iteration count too high */
        log_nametypeclass(VERB_ALGO, "start nsec3 nameerror proof, zone", 
                flt.zone, 0, 0);
        return nsec3_do_prove_nameerror(env, &flt, ct, qinfo, calc);
}

/* 
 * No code to handle qtype=NSEC3 specially. 
 * This existed in early drafts, but was later (-05) removed.
 */

/** Do the nodata proof */
static enum sec_status
nsec3_do_prove_nodata(struct module_env* env, struct nsec3_filter* flt,
        struct nsec3_cache_table* ct, struct query_info* qinfo,
        int* calc)
{
        struct ce_response ce;
        uint8_t* wc;
        size_t wclen;
        struct ub_packed_rrset_key* rrset;
        int rr;
        enum sec_status sec;

        if(find_matching_nsec3(env, flt, ct, qinfo->qname, qinfo->qname_len, 
                &rrset, &rr, calc)) {
                /* cases 1 and 2 */
                if(nsec3_has_type(rrset, rr, qinfo->qtype)) {
                        verbose(VERB_ALGO, "proveNodata: Matching NSEC3 "
                                "proved that type existed, bogus");
                        return sec_status_bogus;
                } else if(nsec3_has_type(rrset, rr, LDNS_RR_TYPE_CNAME)) {
                        verbose(VERB_ALGO, "proveNodata: Matching NSEC3 "
                                "proved that a CNAME existed, bogus");
                        return sec_status_bogus;
                }

                /* 
                 * If type DS: filter_init zone find already found a parent
                 *   zone, so this nsec3 is from a parent zone. 
                 *   o can be not a delegation (unusual query for normal name,
                 *      no DS anyway, but we can verify that).
                 *   o can be a delegation (which is the usual DS check).
                 *   o may not have the SOA bit set (only the top of the
                 *      zone, which must have been above the name, has that).
                 *      Except for the root; which is checked by itself.
                 *
                 * If not type DS: matching nsec3 must not be a delegation.
                 */
                if(qinfo->qtype == LDNS_RR_TYPE_DS && qinfo->qname_len != 1 
                        && nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA) &&
                        !dname_is_root(qinfo->qname)) {
                        verbose(VERB_ALGO, "proveNodata: apex NSEC3 "
                                "abused for no DS proof, bogus");
                        return sec_status_bogus;
                } else if(qinfo->qtype != LDNS_RR_TYPE_DS && 
                        nsec3_has_type(rrset, rr, LDNS_RR_TYPE_NS) &&
                        !nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA)) {
                        if(!nsec3_has_type(rrset, rr, LDNS_RR_TYPE_DS)) {
                                verbose(VERB_ALGO, "proveNodata: matching "
                                        "NSEC3 is insecure delegation");
                                return sec_status_insecure;
                        }
                        verbose(VERB_ALGO, "proveNodata: matching "
                                "NSEC3 is a delegation, bogus");
                        return sec_status_bogus;
                }
                return sec_status_secure;
        }
        if(*calc == MAX_NSEC3_ERRORS) {
                verbose(VERB_ALGO, "proveNodata: all attempted hash "
                        "calculations were erroneous while finding a matching "
                        "NSEC3, bogus");
                return sec_status_bogus;
        } else if(*calc >= MAX_NSEC3_CALCULATIONS) {
                verbose(VERB_ALGO, "proveNodata: reached "
                        "MAX_NSEC3_CALCULATIONS (%d) while finding a "
                        "matching NSEC3; unchecked still",
                        MAX_NSEC3_CALCULATIONS);
                return sec_status_unchecked;
        }

        /* For cases 3 - 5, we need the proven closest encloser, and it 
         * can't match qname. Although, at this point, we know that it 
         * won't since we just checked that. */
        sec = nsec3_prove_closest_encloser(env, flt, ct, qinfo, 1, &ce, calc);
        if(sec == sec_status_bogus) {
                verbose(VERB_ALGO, "proveNodata: did not match qname, "
                          "nor found a proven closest encloser.");
                return sec_status_bogus;
        } else if(sec==sec_status_insecure && qinfo->qtype!=LDNS_RR_TYPE_DS){
                verbose(VERB_ALGO, "proveNodata: closest nsec3 is insecure "
                          "delegation.");
                return sec_status_insecure;
        } else if(sec==sec_status_unchecked) {
                return sec_status_unchecked;
        }

        /* Case 3: removed */

        /* Case 4: */
        log_assert(ce.ce);
        wc = nsec3_ce_wildcard(ct->region, ce.ce, ce.ce_len, &wclen);
        if(wc && find_matching_nsec3(env, flt, ct, wc, wclen, &rrset, &rr,
                calc)) {
                /* found wildcard */
                if(nsec3_has_type(rrset, rr, qinfo->qtype)) {
                        verbose(VERB_ALGO, "nsec3 nodata proof: matching "
                                "wildcard had qtype, bogus");
                        return sec_status_bogus;
                } else if(nsec3_has_type(rrset, rr, LDNS_RR_TYPE_CNAME)) {
                        verbose(VERB_ALGO, "nsec3 nodata proof: matching "
                                "wildcard had a CNAME, bogus");
                        return sec_status_bogus;
                }
                if(qinfo->qtype == LDNS_RR_TYPE_DS && qinfo->qname_len != 1 
                        && nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA)) {
                        verbose(VERB_ALGO, "nsec3 nodata proof: matching "
                                "wildcard for no DS proof has a SOA, bogus");
                        return sec_status_bogus;
                } else if(qinfo->qtype != LDNS_RR_TYPE_DS && 
                        nsec3_has_type(rrset, rr, LDNS_RR_TYPE_NS) &&
                        !nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA)) {
                        verbose(VERB_ALGO, "nsec3 nodata proof: matching "
                                "wildcard is a delegation, bogus");
                        return sec_status_bogus;
                }
                /* everything is peachy keen, except for optout spans */
                if(ce.nc_rrset && nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
                        verbose(VERB_ALGO, "nsec3 nodata proof: matching "
                                "wildcard is in optout range, insecure");
                        return sec_status_insecure;
                }
                return sec_status_secure;
        }
        if(*calc == MAX_NSEC3_ERRORS) {
                verbose(VERB_ALGO, "nsec3 nodata proof: all attempted hash "
                        "calculations were erroneous while matching "
                        "wildcard, bogus");
                return sec_status_bogus;
        } else if(*calc >= MAX_NSEC3_CALCULATIONS) {
                verbose(VERB_ALGO, "nsec3 nodata proof: reached "
                        "MAX_NSEC3_CALCULATIONS (%d) while matching "
                        "wildcard, unchecked still",
                        MAX_NSEC3_CALCULATIONS);
                return sec_status_unchecked;
        }

        /* Case 5: */
        /* Due to forwarders, cnames, and other collating effects, we
         * can see the ordinary unsigned data from a zone beneath an
         * insecure delegation under an optout here */
        if(!ce.nc_rrset) {
                verbose(VERB_ALGO, "nsec3 nodata proof: no next closer nsec3");
                return sec_status_bogus;
        }

        /* We need to make sure that the covering NSEC3 is opt-out. */
        log_assert(ce.nc_rrset);
        if(!nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
                if(qinfo->qtype == LDNS_RR_TYPE_DS)
                  verbose(VERB_ALGO, "proveNodata: covering NSEC3 was not "
                        "opt-out in an opt-out DS NOERROR/NODATA case.");
                else verbose(VERB_ALGO, "proveNodata: could not find matching "
                        "NSEC3, nor matching wildcard, nor optout NSEC3 "
                        "-- no more options, bogus.");
                return sec_status_bogus;
        }
        /* RFC5155 section 9.2: if nc has optout then no AD flag set */
        return sec_status_insecure;
}

enum sec_status
nsec3_prove_nodata(struct module_env* env, struct val_env* ve,
        struct ub_packed_rrset_key** list, size_t num,
        struct query_info* qinfo, struct key_entry_key* kkey,
        struct nsec3_cache_table* ct, int* calc)
{
        struct nsec3_filter flt;

        if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
                return sec_status_bogus; /* no valid NSEC3s, bogus */
        filter_init(&flt, list, num, qinfo); /* init RR iterator */
        if(!flt.zone)
                return sec_status_bogus; /* no RRs */
        if(nsec3_iteration_count_high(ve, &flt, kkey))
                return sec_status_insecure; /* iteration count too high */
        return nsec3_do_prove_nodata(env, &flt, ct, qinfo, calc);
}

enum sec_status
nsec3_prove_wildcard(struct module_env* env, struct val_env* ve,
        struct ub_packed_rrset_key** list, size_t num,
        struct query_info* qinfo, struct key_entry_key* kkey, uint8_t* wc,
        struct nsec3_cache_table* ct, int* calc)
{
        struct nsec3_filter flt;
        struct ce_response ce;
        uint8_t* nc;
        size_t nc_len;
        size_t wclen;
        (void)dname_count_size_labels(wc, &wclen);

        if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
                return sec_status_bogus; /* no valid NSEC3s, bogus */
        filter_init(&flt, list, num, qinfo); /* init RR iterator */
        if(!flt.zone)
                return sec_status_bogus; /* no RRs */
        if(nsec3_iteration_count_high(ve, &flt, kkey))
                return sec_status_insecure; /* iteration count too high */

        /* We know what the (purported) closest encloser is by just 
         * looking at the supposed generating wildcard. 
         * The *. has already been removed from the wc name.
         */
        memset(&ce, 0, sizeof(ce));
        ce.ce = wc;
        ce.ce_len = wclen;

        /* Now we still need to prove that the original data did not exist.
         * Otherwise, we need to show that the next closer name is covered. */
        next_closer(qinfo->qname, qinfo->qname_len, ce.ce, &nc, &nc_len);
        if(!find_covering_nsec3(env, &flt, ct, nc, nc_len,
                &ce.nc_rrset, &ce.nc_rr, calc)) {
                if(*calc == MAX_NSEC3_ERRORS) {
                        verbose(VERB_ALGO, "proveWildcard: did not find a "
                                "covering NSEC3 that covered the next closer "
                                "name; all attempted hash calculations were "
                                "erroneous; bogus");
                        return sec_status_bogus;
                } else if(*calc >= MAX_NSEC3_CALCULATIONS) {
                        verbose(VERB_ALGO, "proveWildcard: did not find a "
                                "covering NSEC3 that covered the next closer "
                                "name; reached MAX_NSEC3_CALCULATIONS "
                                "(%d); unchecked still",
                                MAX_NSEC3_CALCULATIONS);
                        return sec_status_unchecked;
                }
                verbose(VERB_ALGO, "proveWildcard: did not find a covering "
                        "NSEC3 that covered the next closer name.");
                return sec_status_bogus;
        }
        if(ce.nc_rrset && nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
                verbose(VERB_ALGO, "proveWildcard: NSEC3 optout");
                return sec_status_insecure;
        }
        return sec_status_secure;
}

/** test if list is all secure */
static int
list_is_secure(struct module_env* env, struct val_env* ve, 
        struct ub_packed_rrset_key** list, size_t num,
        struct key_entry_key* kkey, char** reason, sldns_ede_code *reason_bogus,
        struct module_qstate* qstate, char* reasonbuf, size_t reasonlen)
{
        struct packed_rrset_data* d;
        size_t i;
        int verified = 0;
        for(i=0; i<num; i++) {
                d = (struct packed_rrset_data*)list[i]->entry.data;
                if(list[i]->rk.type != htons(LDNS_RR_TYPE_NSEC3))
                        continue;
                if(d->security == sec_status_secure)
                        continue;
                rrset_check_sec_status(env->rrset_cache, list[i], *env->now);
                if(d->security == sec_status_secure)
                        continue;
                d->security = val_verify_rrset_entry(env, ve, list[i], kkey,
                        reason, reason_bogus, LDNS_SECTION_AUTHORITY, qstate,
                        &verified, reasonbuf, reasonlen);
                if(d->security != sec_status_secure) {
                        verbose(VERB_ALGO, "NSEC3 did not verify");
                        return 0;
                }
                rrset_update_sec_status(env->rrset_cache, list[i], *env->now);
        }
        return 1;
}

enum sec_status
nsec3_prove_nods(struct module_env* env, struct val_env* ve,
        struct ub_packed_rrset_key** list, size_t num,
        struct query_info* qinfo, struct key_entry_key* kkey, char** reason,
        sldns_ede_code* reason_bogus, struct module_qstate* qstate,
        struct nsec3_cache_table* ct, char* reasonbuf, size_t reasonlen)
{
        struct nsec3_filter flt;
        struct ce_response ce;
        struct ub_packed_rrset_key* rrset;
        int rr;
        int calc = 0;
        enum sec_status sec;

        log_assert(qinfo->qtype == LDNS_RR_TYPE_DS);

        if(!list || num == 0 || !kkey || !key_entry_isgood(kkey)) {
                *reason = "no valid NSEC3s";
                return sec_status_bogus; /* no valid NSEC3s, bogus */
        }
        if(!list_is_secure(env, ve, list, num, kkey, reason, reason_bogus,
                qstate, reasonbuf, reasonlen)) {
                *reason = "not all NSEC3 records secure";
                return sec_status_bogus; /* not all NSEC3 records secure */
        }
        filter_init(&flt, list, num, qinfo); /* init RR iterator */
        if(!flt.zone) {
                *reason = "no NSEC3 records";
                return sec_status_bogus; /* no RRs */
        }
        if(nsec3_iteration_count_high(ve, &flt, kkey))
                return sec_status_insecure; /* iteration count too high */

        /* Look for a matching NSEC3 to qname -- this is the normal 
         * NODATA case. */
        if(find_matching_nsec3(env, &flt, ct, qinfo->qname, qinfo->qname_len,
                &rrset, &rr, &calc)) {
                /* If the matching NSEC3 has the SOA bit set, it is from 
                 * the wrong zone (the child instead of the parent). If 
                 * it has the DS bit set, then we were lied to. */
                if(nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA) && 
                        qinfo->qname_len != 1) {
                        verbose(VERB_ALGO, "nsec3 provenods: NSEC3 is from"
                                " child zone, bogus");
                        *reason = "NSEC3 from child zone";
                        return sec_status_bogus;
                } else if(nsec3_has_type(rrset, rr, LDNS_RR_TYPE_DS)) {
                        verbose(VERB_ALGO, "nsec3 provenods: NSEC3 has qtype"
                                " DS, bogus");
                        *reason = "NSEC3 has DS in bitmap";
                        return sec_status_bogus;
                }
                /* If the NSEC3 RR doesn't have the NS bit set, then 
                 * this wasn't a delegation point. */
                if(!nsec3_has_type(rrset, rr, LDNS_RR_TYPE_NS))
                        return sec_status_indeterminate;
                /* Otherwise, this proves no DS. */
                return sec_status_secure;
        }
        if(calc == MAX_NSEC3_ERRORS) {
                verbose(VERB_ALGO, "nsec3 provenods: all attempted hash "
                        "calculations were erroneous while finding a matching "
                        "NSEC3, bogus");
                return sec_status_bogus;
        } else if(calc >= MAX_NSEC3_CALCULATIONS) {
                verbose(VERB_ALGO, "nsec3 provenods: reached "
                        "MAX_NSEC3_CALCULATIONS (%d) while finding a "
                        "matching NSEC3, unchecked still",
                        MAX_NSEC3_CALCULATIONS);
                return sec_status_unchecked;
        }

        /* Otherwise, we are probably in the opt-out case. */
        sec = nsec3_prove_closest_encloser(env, &flt, ct, qinfo, 1, &ce, &calc);
        if(sec == sec_status_unchecked) {
                return sec_status_unchecked;
        } else if(sec != sec_status_secure) {
                /* an insecure delegation *above* the qname does not prove
                 * anything about this qname exactly, and bogus is bogus */
                verbose(VERB_ALGO, "nsec3 provenods: did not match qname, "
                          "nor found a proven closest encloser.");
                *reason = "no NSEC3 closest encloser";
                return sec_status_bogus;
        }

        /* robust extra check */
        if(!ce.nc_rrset) {
                verbose(VERB_ALGO, "nsec3 nods proof: no next closer nsec3");
                *reason = "no NSEC3 next closer";
                return sec_status_bogus;
        }

        /* we had the closest encloser proof, then we need to check that the
         * covering NSEC3 was opt-out -- the proveClosestEncloser step already
         * checked to see if the closest encloser was a delegation or DNAME.
         */
        log_assert(ce.nc_rrset);
        if(!nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
                verbose(VERB_ALGO, "nsec3 provenods: covering NSEC3 was not "
                        "opt-out in an opt-out DS NOERROR/NODATA case.");
                *reason = "covering NSEC3 was not opt-out in an opt-out "
                        "DS NOERROR/NODATA case";
                return sec_status_bogus;
        }
        /* RFC5155 section 9.2: if nc has optout then no AD flag set */
        return sec_status_insecure;
}

enum sec_status
nsec3_prove_nxornodata(struct module_env* env, struct val_env* ve,
        struct ub_packed_rrset_key** list, size_t num,
        struct query_info* qinfo, struct key_entry_key* kkey, int* nodata,
        struct  nsec3_cache_table* ct, int* calc)
{
        enum sec_status sec, secnx;
        struct nsec3_filter flt;
        *nodata = 0;

        if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
                return sec_status_bogus; /* no valid NSEC3s, bogus */
        filter_init(&flt, list, num, qinfo); /* init RR iterator */
        if(!flt.zone)
                return sec_status_bogus; /* no RRs */
        if(nsec3_iteration_count_high(ve, &flt, kkey))
                return sec_status_insecure; /* iteration count too high */

        /* try nxdomain and nodata after another, while keeping the
         * hash cache intact */

        secnx = nsec3_do_prove_nameerror(env, &flt, ct, qinfo, calc);
        if(secnx==sec_status_secure)
                return sec_status_secure;
        else if(secnx == sec_status_unchecked)
                return sec_status_unchecked;
        sec = nsec3_do_prove_nodata(env, &flt, ct, qinfo, calc);
        if(sec==sec_status_secure) {
                *nodata = 1;
        } else if(sec == sec_status_insecure) {
                *nodata = 1;
        } else if(secnx == sec_status_insecure) {
                sec = sec_status_insecure;
        } else if(sec == sec_status_unchecked) {
                return sec_status_unchecked;
        }
        return sec;
}