xref: /netbsd-src/external/bsd/unbound/dist/util/data/msgreply.c (revision 91f7d55fb697b5e0475da4718fa34c3a3ebeac85)

/*
 * util/data/msgreply.c - store message and reply data.
 *
 * 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 a data structure to store a message and its reply.
 */

#include "config.h"
#include "util/data/msgreply.h"
#include "util/storage/lookup3.h"
#include "util/log.h"
#include "util/alloc.h"
#include "util/netevent.h"
#include "util/net_help.h"
#include "util/data/dname.h"
#include "util/regional.h"
#include "util/data/msgparse.h"
#include "util/data/msgencode.h"
#include "sldns/sbuffer.h"
#include "sldns/wire2str.h"
#include "util/module.h"
#include "util/fptr_wlist.h"

/** MAX TTL default for messages and rrsets */
time_t MAX_TTL = 3600 * 24 * 10; /* ten days */
/** MIN TTL default for messages and rrsets */
time_t MIN_TTL = 0;
/** MAX Negative TTL, for SOA records in authority section */
time_t MAX_NEG_TTL = 3600; /* one hour */
/** If we serve expired entries and prefetch them */
int SERVE_EXPIRED = 0;
/** Time to serve records after expiration */
time_t SERVE_EXPIRED_TTL = 0;
/** TTL to use for expired records */
time_t SERVE_EXPIRED_REPLY_TTL = 30;
/** If we serve the original TTL or decrementing TTLs */
int SERVE_ORIGINAL_TTL = 0;

/** allocate qinfo, return 0 on error */
static int
parse_create_qinfo(sldns_buffer* pkt, struct msg_parse* msg,
	struct query_info* qinf, struct regional* region)
{
	if(msg->qname) {
		if(region)
			qinf->qname = (uint8_t*)regional_alloc(region,
				msg->qname_len);
		else	qinf->qname = (uint8_t*)malloc(msg->qname_len);
		if(!qinf->qname) return 0;
		dname_pkt_copy(pkt, qinf->qname, msg->qname);
	} else	qinf->qname = 0;
	qinf->qname_len = msg->qname_len;
	qinf->qtype = msg->qtype;
	qinf->qclass = msg->qclass;
	qinf->local_alias = NULL;
	return 1;
}

/** constructor for replyinfo */
struct reply_info*
construct_reply_info_base(struct regional* region, uint16_t flags, size_t qd,
	time_t ttl, time_t prettl, time_t expttl, size_t an, size_t ns,
	size_t ar, size_t total, enum sec_status sec, sldns_ede_code reason_bogus)
{
	struct reply_info* rep;
	/* rrset_count-1 because the first ref is part of the struct. */
	size_t s = sizeof(struct reply_info) - sizeof(struct rrset_ref) +
		sizeof(struct ub_packed_rrset_key*) * total;
	if(total >= RR_COUNT_MAX) return NULL; /* sanity check on numRRS*/
	if(region)
		rep = (struct reply_info*)regional_alloc(region, s);
	else	rep = (struct reply_info*)malloc(s +
			sizeof(struct rrset_ref) * (total));
	if(!rep)
		return NULL;
	rep->flags = flags;
	rep->qdcount = qd;
	rep->ttl = ttl;
	rep->prefetch_ttl = prettl;
	rep->serve_expired_ttl = expttl;
	rep->an_numrrsets = an;
	rep->ns_numrrsets = ns;
	rep->ar_numrrsets = ar;
	rep->rrset_count = total;
	rep->security = sec;
	rep->reason_bogus = reason_bogus;
	/* this is only allocated and used for caching on copy */
	rep->reason_bogus_str = NULL;
	rep->authoritative = 0;
	/* array starts after the refs */
	if(region)
		rep->rrsets = (struct ub_packed_rrset_key**)&(rep->ref[0]);
	else	rep->rrsets = (struct ub_packed_rrset_key**)&(rep->ref[total]);
	/* zero the arrays to assist cleanup in case of malloc failure */
	memset( rep->rrsets, 0, sizeof(struct ub_packed_rrset_key*) * total);
	if(!region)
		memset( &rep->ref[0], 0, sizeof(struct rrset_ref) * total);
	return rep;
}

/** allocate replyinfo, return 0 on error */
static int
parse_create_repinfo(struct msg_parse* msg, struct reply_info** rep,
	struct regional* region)
{
	*rep = construct_reply_info_base(region, msg->flags, msg->qdcount, 0,
		0, 0, msg->an_rrsets, msg->ns_rrsets, msg->ar_rrsets,
		msg->rrset_count, sec_status_unchecked, LDNS_EDE_NONE);
	if(!*rep)
		return 0;
	return 1;
}

int
reply_info_alloc_rrset_keys(struct reply_info* rep, struct alloc_cache* alloc,
	struct regional* region)
{
	size_t i;
	for(i=0; i<rep->rrset_count; i++) {
		if(region) {
			rep->rrsets[i] = (struct ub_packed_rrset_key*)
				regional_alloc(region,
				sizeof(struct ub_packed_rrset_key));
			if(rep->rrsets[i]) {
				memset(rep->rrsets[i], 0,
					sizeof(struct ub_packed_rrset_key));
				rep->rrsets[i]->entry.key = rep->rrsets[i];
			}
		}
		else	rep->rrsets[i] = alloc_special_obtain(alloc);
		if(!rep->rrsets[i])
			return 0;
		rep->rrsets[i]->entry.data = NULL;
	}
	return 1;
}

struct reply_info *
make_new_reply_info(const struct reply_info* rep, struct regional* region,
	size_t an_numrrsets, size_t copy_rrsets)
{
	struct reply_info* new_rep;
	size_t i;

	/* create a base struct.  we specify 'insecure' security status as
	 * the modified response won't be DNSSEC-valid.  In our faked response
	 * the authority and additional sections will be empty (except possible
	 * EDNS0 OPT RR in the additional section appended on sending it out),
	 * so the total number of RRsets is an_numrrsets. */
	new_rep = construct_reply_info_base(region, rep->flags,
		rep->qdcount, rep->ttl, rep->prefetch_ttl,
		rep->serve_expired_ttl, an_numrrsets, 0, 0, an_numrrsets,
		sec_status_insecure, LDNS_EDE_NONE);
	if(!new_rep)
		return NULL;
	if(!reply_info_alloc_rrset_keys(new_rep, NULL, region))
		return NULL;
	for(i=0; i<copy_rrsets; i++)
		new_rep->rrsets[i] = rep->rrsets[i];

	return new_rep;
}

/** find the minimumttl in the rdata of SOA record */
static time_t
soa_find_minttl(struct rr_parse* rr)
{
	uint16_t rlen = sldns_read_uint16(rr->ttl_data+4);
	if(rlen < 20)
		return 0; /* rdata too small for SOA (dname, dname, 5*32bit) */
	/* minimum TTL is the last 32bit value in the rdata of the record */
	/* at position ttl_data + 4(ttl) + 2(rdatalen) + rdatalen - 4(timeval)*/
	return (time_t)sldns_read_uint32(rr->ttl_data+6+rlen-4);
}

/** do the rdata copy */
static int
rdata_copy(sldns_buffer* pkt, struct packed_rrset_data* data, uint8_t* to,
	struct rr_parse* rr, time_t* rr_ttl, uint16_t type,
	sldns_pkt_section section)
{
	uint16_t pkt_len;
	const sldns_rr_descriptor* desc;

	*rr_ttl = sldns_read_uint32(rr->ttl_data);
	/* RFC 2181 Section 8. if msb of ttl is set treat as if zero. */
	if(*rr_ttl & 0x80000000U)
		*rr_ttl = 0;
	if(type == LDNS_RR_TYPE_SOA && section == LDNS_SECTION_AUTHORITY) {
		/* negative response. see if TTL of SOA record larger than the
		 * minimum-ttl in the rdata of the SOA record */
		if(*rr_ttl > soa_find_minttl(rr))
			*rr_ttl = soa_find_minttl(rr);
	}
	if(!SERVE_ORIGINAL_TTL && (*rr_ttl < MIN_TTL))
		*rr_ttl = MIN_TTL;
	if(!SERVE_ORIGINAL_TTL && (*rr_ttl > MAX_TTL))
		*rr_ttl = MAX_TTL;
	if(type == LDNS_RR_TYPE_SOA && section == LDNS_SECTION_AUTHORITY) {
		/* max neg ttl overrides the min and max ttl of everything
		 * else, it is for a more specific record */
		if(*rr_ttl > MAX_NEG_TTL)
			*rr_ttl = MAX_NEG_TTL;
	}
	if(*rr_ttl < data->ttl)
		data->ttl = *rr_ttl;

	if(rr->outside_packet) {
		/* uncompressed already, only needs copy */
		memmove(to, rr->ttl_data+sizeof(uint32_t), rr->size);
		return 1;
	}

	sldns_buffer_set_position(pkt, (size_t)
		(rr->ttl_data - sldns_buffer_begin(pkt) + sizeof(uint32_t)));
	/* insert decompressed size into rdata len stored in memory */
	/* -2 because rdatalen bytes are not included. */
	pkt_len = htons(rr->size - 2);
	memmove(to, &pkt_len, sizeof(uint16_t));
	to += 2;
	/* read packet rdata len */
	pkt_len = sldns_buffer_read_u16(pkt);
	if(sldns_buffer_remaining(pkt) < pkt_len)
		return 0;
	desc = sldns_rr_descript(type);
	if(pkt_len > 0 && desc && desc->_dname_count > 0) {
		int count = (int)desc->_dname_count;
		int rdf = 0;
		size_t len;
		size_t oldpos;
		/* decompress dnames. */
		while(pkt_len > 0 && count) {
			switch(desc->_wireformat[rdf]) {
			case LDNS_RDF_TYPE_DNAME:
				oldpos = sldns_buffer_position(pkt);
				dname_pkt_copy(pkt, to,
					sldns_buffer_current(pkt));
				to += pkt_dname_len(pkt);
				pkt_len -= sldns_buffer_position(pkt)-oldpos;
				count--;
				len = 0;
				break;
			case LDNS_RDF_TYPE_STR:
				len = sldns_buffer_current(pkt)[0] + 1;
				break;
			default:
				len = get_rdf_size(desc->_wireformat[rdf]);
				break;
			}
			if(len) {
				log_assert(len <= pkt_len);
				memmove(to, sldns_buffer_current(pkt), len);
				to += len;
				sldns_buffer_skip(pkt, (ssize_t)len);
				pkt_len -= len;
			}
			rdf++;
		}
	}
	/* copy remaining rdata */
	if(pkt_len >  0)
		memmove(to, sldns_buffer_current(pkt), pkt_len);

	return 1;
}

/** copy over the data into packed rrset */
static int
parse_rr_copy(sldns_buffer* pkt, struct rrset_parse* pset,
	struct packed_rrset_data* data)
{
	size_t i;
	struct rr_parse* rr = pset->rr_first;
	uint8_t* nextrdata;
	size_t total = pset->rr_count + pset->rrsig_count;
	data->ttl = MAX_TTL;
	data->count = pset->rr_count;
	data->rrsig_count = pset->rrsig_count;
	data->trust = rrset_trust_none;
	data->security = sec_status_unchecked;
	/* layout: struct - rr_len - rr_data - rr_ttl - rdata - rrsig */
	data->rr_len = (size_t*)((uint8_t*)data +
		sizeof(struct packed_rrset_data));
	data->rr_data = (uint8_t**)&(data->rr_len[total]);
	data->rr_ttl = (time_t*)&(data->rr_data[total]);
	nextrdata = (uint8_t*)&(data->rr_ttl[total]);
	for(i=0; i<data->count; i++) {
		data->rr_len[i] = rr->size;
		data->rr_data[i] = nextrdata;
		nextrdata += rr->size;
		if(!rdata_copy(pkt, data, data->rr_data[i], rr,
			&data->rr_ttl[i], pset->type, pset->section))
			return 0;
		rr = rr->next;
	}
	/* if rrsig, its rdata is at nextrdata */
	rr = pset->rrsig_first;
	for(i=data->count; i<total; i++) {
		data->rr_len[i] = rr->size;
		data->rr_data[i] = nextrdata;
		nextrdata += rr->size;
		if(!rdata_copy(pkt, data, data->rr_data[i], rr,
			&data->rr_ttl[i], LDNS_RR_TYPE_RRSIG, pset->section))
			return 0;
		rr = rr->next;
	}
	return 1;
}

/** create rrset return 0 on failure */
static int
parse_create_rrset(sldns_buffer* pkt, struct rrset_parse* pset,
	struct packed_rrset_data** data, struct regional* region)
{
	/* allocate */
	size_t s;
	if(pset->rr_count > RR_COUNT_MAX || pset->rrsig_count > RR_COUNT_MAX ||
		pset->size > RR_COUNT_MAX)
		return 0; /* protect against integer overflow */
	s = sizeof(struct packed_rrset_data) +
		(pset->rr_count + pset->rrsig_count) *
		(sizeof(size_t)+sizeof(uint8_t*)+sizeof(time_t)) +
		pset->size;
	if(region)
		*data = regional_alloc_zero(region, s);
	else	*data = calloc(1, s);
	if(!*data)
		return 0;
	/* copy & decompress */
	if(!parse_rr_copy(pkt, pset, *data)) {
		if(!region) {
			free(*data);
			*data = NULL;
		}
		return 0;
	}
	return 1;
}

/** get trust value for rrset */
static enum rrset_trust
get_rrset_trust(struct msg_parse* msg, struct rrset_parse* rrset)
{
	uint16_t AA = msg->flags & BIT_AA;
	if(rrset->section == LDNS_SECTION_ANSWER) {
		if(AA) {
			/* RFC2181 says remainder of CNAME chain is nonauth*/
			if(msg->rrset_first &&
				msg->rrset_first->section==LDNS_SECTION_ANSWER
				&& msg->rrset_first->type==LDNS_RR_TYPE_CNAME){
				if(rrset == msg->rrset_first)
					return rrset_trust_ans_AA;
				else 	return rrset_trust_ans_noAA;
			}
			if(msg->rrset_first &&
				msg->rrset_first->section==LDNS_SECTION_ANSWER
				&& msg->rrset_first->type==LDNS_RR_TYPE_DNAME){
				if(rrset == msg->rrset_first ||
				   rrset == msg->rrset_first->rrset_all_next)
					return rrset_trust_ans_AA;
				else 	return rrset_trust_ans_noAA;
			}
			return rrset_trust_ans_AA;
		}
		else	return rrset_trust_ans_noAA;
	} else if(rrset->section == LDNS_SECTION_AUTHORITY) {
		if(AA)	return rrset_trust_auth_AA;
		else	return rrset_trust_auth_noAA;
	} else {
		/* addit section */
		if(AA)	return rrset_trust_add_AA;
		else	return rrset_trust_add_noAA;
	}
	/* NOTREACHED */
	return rrset_trust_none;
}

int
parse_copy_decompress_rrset(sldns_buffer* pkt, struct msg_parse* msg,
	struct rrset_parse *pset, struct regional* region,
	struct ub_packed_rrset_key* pk)
{
	struct packed_rrset_data* data;
	pk->rk.flags = pset->flags;
	pk->rk.dname_len = pset->dname_len;
	if(region)
		pk->rk.dname = (uint8_t*)regional_alloc(
			region, pset->dname_len);
	else	pk->rk.dname =
			(uint8_t*)malloc(pset->dname_len);
	if(!pk->rk.dname)
		return 0;
	/** copy & decompress dname */
	dname_pkt_copy(pkt, pk->rk.dname, pset->dname);
	/** copy over type and class */
	pk->rk.type = htons(pset->type);
	pk->rk.rrset_class = pset->rrset_class;
	/** read data part. */
	if(!parse_create_rrset(pkt, pset, &data, region)) {
		if(!region) {
			free(pk->rk.dname);
			pk->rk.dname = NULL;
		}
		return 0;
	}
	pk->entry.data = (void*)data;
	pk->entry.key = (void*)pk;
	pk->entry.hash = pset->hash;
	data->trust = get_rrset_trust(msg, pset);
	return 1;
}

/**
 * Copy and decompress rrs
 * @param pkt: the packet for compression pointer resolution.
 * @param msg: the parsed message
 * @param rep: reply info to put rrs into.
 * @param region: if not NULL, used for allocation.
 * @return 0 on failure.
 */
static int
parse_copy_decompress(sldns_buffer* pkt, struct msg_parse* msg,
	struct reply_info* rep, struct regional* region)
{
	size_t i;
	struct rrset_parse *pset = msg->rrset_first;
	struct packed_rrset_data* data;
	log_assert(rep);
	rep->ttl = MAX_TTL;
	rep->security = sec_status_unchecked;
	if(rep->rrset_count == 0)
		rep->ttl = NORR_TTL;

	for(i=0; i<rep->rrset_count; i++) {
		if(!parse_copy_decompress_rrset(pkt, msg, pset, region,
			rep->rrsets[i]))
			return 0;
		data = (struct packed_rrset_data*)rep->rrsets[i]->entry.data;
		if(data->ttl < rep->ttl)
			rep->ttl = data->ttl;

		pset = pset->rrset_all_next;
	}
	rep->prefetch_ttl = PREFETCH_TTL_CALC(rep->ttl);
	rep->serve_expired_ttl = rep->ttl + SERVE_EXPIRED_TTL;
	return 1;
}

int
parse_create_msg(sldns_buffer* pkt, struct msg_parse* msg,
	struct alloc_cache* alloc, struct query_info* qinf,
	struct reply_info** rep, struct regional* region)
{
	log_assert(pkt && msg);
	if(!parse_create_qinfo(pkt, msg, qinf, region))
		return 0;
	if(!parse_create_repinfo(msg, rep, region))
		return 0;
	if(!reply_info_alloc_rrset_keys(*rep, alloc, region)) {
		if(!region) reply_info_parsedelete(*rep, alloc);
		return 0;
	}
	if(!parse_copy_decompress(pkt, msg, *rep, region)) {
		if(!region) reply_info_parsedelete(*rep, alloc);
		return 0;
	}
	return 1;
}

int reply_info_parse(sldns_buffer* pkt, struct alloc_cache* alloc,
        struct query_info* qinf, struct reply_info** rep,
	struct regional* region, struct edns_data* edns)
{
	/* use scratch pad region-allocator during parsing. */
	struct msg_parse* msg;
	int ret;

	qinf->qname = NULL;
	qinf->local_alias = NULL;
	*rep = NULL;
	if(!(msg = regional_alloc(region, sizeof(*msg)))) {
		return LDNS_RCODE_SERVFAIL;
	}
	memset(msg, 0, sizeof(*msg));

	sldns_buffer_set_position(pkt, 0);
	if((ret = parse_packet(pkt, msg, region)) != 0) {
		return ret;
	}
	if((ret = parse_extract_edns_from_response_msg(msg, edns, region)) != 0)
		return ret;

	/* parse OK, allocate return structures */
	/* this also performs dname decompression */
	if(!parse_create_msg(pkt, msg, alloc, qinf, rep, NULL)) {
		query_info_clear(qinf);
		*rep = NULL;
		return LDNS_RCODE_SERVFAIL;
	}
	return 0;
}

/** helper compare function to sort in lock order */
static int
reply_info_sortref_cmp(const void* a, const void* b)
{
	struct rrset_ref* x = (struct rrset_ref*)a;
	struct rrset_ref* y = (struct rrset_ref*)b;
	if(x->key < y->key) return -1;
	if(x->key > y->key) return 1;
	return 0;
}

void
reply_info_sortref(struct reply_info* rep)
{
	qsort(&rep->ref[0], rep->rrset_count, sizeof(struct rrset_ref),
		reply_info_sortref_cmp);
}

void
reply_info_set_ttls(struct reply_info* rep, time_t timenow)
{
	size_t i, j;
	rep->ttl += timenow;
	rep->prefetch_ttl += timenow;
	rep->serve_expired_ttl += timenow;
	for(i=0; i<rep->rrset_count; i++) {
		struct packed_rrset_data* data = (struct packed_rrset_data*)
			rep->ref[i].key->entry.data;
		if(i>0 && rep->ref[i].key == rep->ref[i-1].key)
			continue;
		data->ttl += timenow;
		for(j=0; j<data->count + data->rrsig_count; j++) {
			data->rr_ttl[j] += timenow;
		}
		data->ttl_add = timenow;
	}
}

void
reply_info_parsedelete(struct reply_info* rep, struct alloc_cache* alloc)
{
	size_t i;
	if(!rep)
		return;
	/* no need to lock, since not shared in hashtables. */
	for(i=0; i<rep->rrset_count; i++) {
		ub_packed_rrset_parsedelete(rep->rrsets[i], alloc);
	}
	if(rep->reason_bogus_str) {
		free(rep->reason_bogus_str);
		rep->reason_bogus_str = NULL;
	}
	free(rep);
}

int
query_info_parse(struct query_info* m, sldns_buffer* query)
{
	uint8_t* q = sldns_buffer_begin(query);
	/* minimum size: header + \0 + qtype + qclass */
	if(sldns_buffer_limit(query) < LDNS_HEADER_SIZE + 5)
		return 0;
	if((LDNS_OPCODE_WIRE(q) != LDNS_PACKET_QUERY && LDNS_OPCODE_WIRE(q) !=
		LDNS_PACKET_NOTIFY) || LDNS_QDCOUNT(q) != 1 ||
		sldns_buffer_position(query) != 0)
		return 0;
	sldns_buffer_skip(query, LDNS_HEADER_SIZE);
	m->qname = sldns_buffer_current(query);
	if((m->qname_len = query_dname_len(query)) == 0)
		return 0; /* parse error */
	if(sldns_buffer_remaining(query) < 4)
		return 0; /* need qtype, qclass */
	m->qtype = sldns_buffer_read_u16(query);
	m->qclass = sldns_buffer_read_u16(query);
	m->local_alias = NULL;
	return 1;
}

/** tiny subroutine for msgreply_compare */
#define COMPARE_IT(x, y) \
	if( (x) < (y) ) return -1; \
	else if( (x) > (y) ) return +1; \
	log_assert( (x) == (y) );

int
query_info_compare(void* m1, void* m2)
{
	struct query_info* msg1 = (struct query_info*)m1;
	struct query_info* msg2 = (struct query_info*)m2;
	int mc;
	/* from most different to least different for speed */
	COMPARE_IT(msg1->qtype, msg2->qtype);
	if((mc = query_dname_compare(msg1->qname, msg2->qname)) != 0)
		return mc;
	log_assert(msg1->qname_len == msg2->qname_len);
	COMPARE_IT(msg1->qclass, msg2->qclass);
	return 0;
#undef COMPARE_IT
}

void
query_info_clear(struct query_info* m)
{
	free(m->qname);
	m->qname = NULL;
}

size_t
msgreply_sizefunc(void* k, void* d)
{
	struct msgreply_entry* q = (struct msgreply_entry*)k;
	struct reply_info* r = (struct reply_info*)d;
	size_t s = sizeof(struct msgreply_entry) + sizeof(struct reply_info)
		+ q->key.qname_len + lock_get_mem(&q->entry.lock)
		- sizeof(struct rrset_ref);
	s += r->rrset_count * sizeof(struct rrset_ref);
	s += r->rrset_count * sizeof(struct ub_packed_rrset_key*);
	return s;
}

void
query_entry_delete(void *k, void* ATTR_UNUSED(arg))
{
	struct msgreply_entry* q = (struct msgreply_entry*)k;
	lock_rw_destroy(&q->entry.lock);
	query_info_clear(&q->key);
	free(q);
}

void
reply_info_delete(void* d, void* ATTR_UNUSED(arg))
{
	struct reply_info* r = (struct reply_info*)d;
	if(r->reason_bogus_str) {
		free(r->reason_bogus_str);
		r->reason_bogus_str = NULL;
	}
	free(r);
}

hashvalue_type
query_info_hash(struct query_info *q, uint16_t flags)
{
	hashvalue_type h = 0xab;
	h = hashlittle(&q->qtype, sizeof(q->qtype), h);
	if(q->qtype == LDNS_RR_TYPE_AAAA && (flags&BIT_CD))
		h++;
	h = hashlittle(&q->qclass, sizeof(q->qclass), h);
	h = dname_query_hash(q->qname, h);
	return h;
}

struct msgreply_entry*
query_info_entrysetup(struct query_info* q, struct reply_info* r,
	hashvalue_type h)
{
	struct msgreply_entry* e = (struct msgreply_entry*)malloc(
		sizeof(struct msgreply_entry));
	if(!e) return NULL;
	memcpy(&e->key, q, sizeof(*q));
	e->entry.hash = h;
	e->entry.key = e;
	e->entry.data = r;
	lock_rw_init(&e->entry.lock);
	lock_protect(&e->entry.lock, &e->key.qname, sizeof(e->key.qname));
	lock_protect(&e->entry.lock, &e->key.qname_len, sizeof(e->key.qname_len));
	lock_protect(&e->entry.lock, &e->key.qtype, sizeof(e->key.qtype));
	lock_protect(&e->entry.lock, &e->key.qclass, sizeof(e->key.qclass));
	lock_protect(&e->entry.lock, &e->key.local_alias, sizeof(e->key.local_alias));
	lock_protect(&e->entry.lock, &e->entry.hash, sizeof(e->entry.hash));
	lock_protect(&e->entry.lock, &e->entry.key, sizeof(e->entry.key));
	lock_protect(&e->entry.lock, &e->entry.data, sizeof(e->entry.data));
	lock_protect(&e->entry.lock, e->key.qname, e->key.qname_len);
	q->qname = NULL;
	return e;
}

/** copy rrsets from replyinfo to dest replyinfo */
static int
repinfo_copy_rrsets(struct reply_info* dest, struct reply_info* from,
	struct regional* region)
{
	size_t i, s;
	struct packed_rrset_data* fd, *dd;
	struct ub_packed_rrset_key* fk, *dk;
	for(i=0; i<dest->rrset_count; i++) {
		fk = from->rrsets[i];
		dk = dest->rrsets[i];
		fd = (struct packed_rrset_data*)fk->entry.data;
		dk->entry.hash = fk->entry.hash;
		dk->rk = fk->rk;
		if(region) {
			dk->id = fk->id;
			dk->rk.dname = (uint8_t*)regional_alloc_init(region,
				fk->rk.dname, fk->rk.dname_len);
		} else
			dk->rk.dname = (uint8_t*)memdup(fk->rk.dname,
				fk->rk.dname_len);
		if(!dk->rk.dname)
			return 0;
		s = packed_rrset_sizeof(fd);
		if(region)
			dd = (struct packed_rrset_data*)regional_alloc_init(
				region, fd, s);
		else	dd = (struct packed_rrset_data*)memdup(fd, s);
		if(!dd)
			return 0;
		packed_rrset_ptr_fixup(dd);
		dk->entry.data = (void*)dd;
	}
	return 1;
}

struct reply_info*
reply_info_copy(struct reply_info* rep, struct alloc_cache* alloc,
	struct regional* region)
{
	struct reply_info* cp;
	cp = construct_reply_info_base(region, rep->flags, rep->qdcount,
		rep->ttl, rep->prefetch_ttl, rep->serve_expired_ttl,
		rep->an_numrrsets, rep->ns_numrrsets, rep->ar_numrrsets,
		rep->rrset_count, rep->security, rep->reason_bogus);
	if(!cp)
		return NULL;

	if(rep->reason_bogus_str && *rep->reason_bogus_str != 0) {
		if(region) {
			cp->reason_bogus_str = (char*)regional_alloc(region,
				sizeof(char)
				* (strlen(rep->reason_bogus_str)+1));
		} else {
			cp->reason_bogus_str = malloc(sizeof(char)
				* (strlen(rep->reason_bogus_str)+1));
		}
		if(!cp->reason_bogus_str) {
			if(!region)
				reply_info_parsedelete(cp, alloc);
			return NULL;
		}
		memcpy(cp->reason_bogus_str, rep->reason_bogus_str,
			strlen(rep->reason_bogus_str)+1);
	}

	/* allocate ub_key structures special or not */
	if(!reply_info_alloc_rrset_keys(cp, alloc, region)) {
		if(!region)
			reply_info_parsedelete(cp, alloc);
		return NULL;
	}
	if(!repinfo_copy_rrsets(cp, rep, region)) {
		if(!region)
			reply_info_parsedelete(cp, alloc);
		return NULL;
	}
	return cp;
}

uint8_t*
reply_find_final_cname_target(struct query_info* qinfo, struct reply_info* rep)
{
	uint8_t* sname = qinfo->qname;
	size_t snamelen = qinfo->qname_len;
	size_t i;
	for(i=0; i<rep->an_numrrsets; i++) {
		struct ub_packed_rrset_key* s = rep->rrsets[i];
		/* follow CNAME chain (if any) */
		if(ntohs(s->rk.type) == LDNS_RR_TYPE_CNAME &&
			ntohs(s->rk.rrset_class) == qinfo->qclass &&
			snamelen == s->rk.dname_len &&
			query_dname_compare(sname, s->rk.dname) == 0) {
			get_cname_target(s, &sname, &snamelen);
		}
	}
	if(sname != qinfo->qname)
		return sname;
	return NULL;
}

struct ub_packed_rrset_key*
reply_find_answer_rrset(struct query_info* qinfo, struct reply_info* rep)
{
	uint8_t* sname = qinfo->qname;
	size_t snamelen = qinfo->qname_len;
	size_t i;
	for(i=0; i<rep->an_numrrsets; i++) {
		struct ub_packed_rrset_key* s = rep->rrsets[i];
		/* first match type, for query of qtype cname */
		if(ntohs(s->rk.type) == qinfo->qtype &&
			ntohs(s->rk.rrset_class) == qinfo->qclass &&
			snamelen == s->rk.dname_len &&
			query_dname_compare(sname, s->rk.dname) == 0) {
			return s;
		}
		/* follow CNAME chain (if any) */
		if(ntohs(s->rk.type) == LDNS_RR_TYPE_CNAME &&
			ntohs(s->rk.rrset_class) == qinfo->qclass &&
			snamelen == s->rk.dname_len &&
			query_dname_compare(sname, s->rk.dname) == 0) {
			get_cname_target(s, &sname, &snamelen);
		}
	}
	return NULL;
}

struct ub_packed_rrset_key* reply_find_rrset_section_an(struct reply_info* rep,
	uint8_t* name, size_t namelen, uint16_t type, uint16_t dclass)
{
	size_t i;
	for(i=0; i<rep->an_numrrsets; i++) {
		struct ub_packed_rrset_key* s = rep->rrsets[i];
		if(ntohs(s->rk.type) == type &&
			ntohs(s->rk.rrset_class) == dclass &&
			namelen == s->rk.dname_len &&
			query_dname_compare(name, s->rk.dname) == 0) {
			return s;
		}
	}
	return NULL;
}

struct ub_packed_rrset_key* reply_find_rrset_section_ns(struct reply_info* rep,
	uint8_t* name, size_t namelen, uint16_t type, uint16_t dclass)
{
	size_t i;
	for(i=rep->an_numrrsets; i<rep->an_numrrsets+rep->ns_numrrsets; i++) {
		struct ub_packed_rrset_key* s = rep->rrsets[i];
		if(ntohs(s->rk.type) == type &&
			ntohs(s->rk.rrset_class) == dclass &&
			namelen == s->rk.dname_len &&
			query_dname_compare(name, s->rk.dname) == 0) {
			return s;
		}
	}
	return NULL;
}

struct ub_packed_rrset_key* reply_find_rrset(struct reply_info* rep,
	uint8_t* name, size_t namelen, uint16_t type, uint16_t dclass)
{
	size_t i;
	for(i=0; i<rep->rrset_count; i++) {
		struct ub_packed_rrset_key* s = rep->rrsets[i];
		if(ntohs(s->rk.type) == type &&
			ntohs(s->rk.rrset_class) == dclass &&
			namelen == s->rk.dname_len &&
			query_dname_compare(name, s->rk.dname) == 0) {
			return s;
		}
	}
	return NULL;
}

void
log_dns_msg(const char* str, struct query_info* qinfo, struct reply_info* rep)
{
	/* not particularly fast but flexible, make wireformat and print */
	sldns_buffer* buf = sldns_buffer_new(65535);
	struct regional* region = regional_create();
	if(!(buf && region)) {
		log_err("%s: log_dns_msg: out of memory", str);
		sldns_buffer_free(buf);
		regional_destroy(region);
		return;
	}
	if(!reply_info_encode(qinfo, rep, 0, rep->flags, buf, 0,
		region, 65535, 1, 0)) {
		log_err("%s: log_dns_msg: out of memory", str);
	} else {
		char* s = sldns_wire2str_pkt(sldns_buffer_begin(buf),
			sldns_buffer_limit(buf));
		if(!s) {
			log_info("%s: log_dns_msg: ldns tostr failed", str);
		} else {
			log_info("%s %s", str, s);
		}
		free(s);
	}
	sldns_buffer_free(buf);
	regional_destroy(region);
}

void
log_reply_info(enum verbosity_value v, struct query_info *qinf,
	struct sockaddr_storage *addr, socklen_t addrlen, struct timeval dur,
	int cached, struct sldns_buffer *rmsg)
{
	char qname_buf[LDNS_MAX_DOMAINLEN+1];
	char clientip_buf[128];
	char rcode_buf[16];
	char type_buf[16];
	char class_buf[16];
	size_t pktlen;
	uint16_t rcode = FLAGS_GET_RCODE(sldns_buffer_read_u16_at(rmsg, 2));

	if(verbosity < v)
	  return;

	sldns_wire2str_rcode_buf((int)rcode, rcode_buf, sizeof(rcode_buf));
	addr_to_str(addr, addrlen, clientip_buf, sizeof(clientip_buf));
	if(rcode == LDNS_RCODE_FORMERR)
	{
		if(LOG_TAG_QUERYREPLY)
			log_reply("%s - - - %s - - - ", clientip_buf, rcode_buf);
		else	log_info("%s - - - %s - - - ", clientip_buf, rcode_buf);
	} else {
		if(qinf->qname)
			dname_str(qinf->qname, qname_buf);
		else	snprintf(qname_buf, sizeof(qname_buf), "null");
		pktlen = sldns_buffer_limit(rmsg);
		sldns_wire2str_type_buf(qinf->qtype, type_buf, sizeof(type_buf));
		sldns_wire2str_class_buf(qinf->qclass, class_buf, sizeof(class_buf));
		if(LOG_TAG_QUERYREPLY)
		     log_reply("%s %s %s %s %s " ARG_LL "d.%6.6d %d %d",
			clientip_buf, qname_buf, type_buf, class_buf,
			rcode_buf, (long long)dur.tv_sec, (int)dur.tv_usec, cached, (int)pktlen);
		else log_info("%s %s %s %s %s " ARG_LL "d.%6.6d %d %d",
			clientip_buf, qname_buf, type_buf, class_buf,
			rcode_buf, (long long)dur.tv_sec, (int)dur.tv_usec, cached, (int)pktlen);
	}
}

void
log_query_info(enum verbosity_value v, const char* str,
	struct query_info* qinf)
{
	log_nametypeclass(v, str, qinf->qname, qinf->qtype, qinf->qclass);
}

int
reply_check_cname_chain(struct query_info* qinfo, struct reply_info* rep)
{
	/* check only answer section rrs for matching cname chain.
	 * the cache may return changed rdata, but owner names are untouched.*/
	size_t i;
	uint8_t* sname = qinfo->qname;
	size_t snamelen = qinfo->qname_len;
	for(i=0; i<rep->an_numrrsets; i++) {
		uint16_t t = ntohs(rep->rrsets[i]->rk.type);
		if(t == LDNS_RR_TYPE_DNAME)
			continue; /* skip dnames; note TTL 0 not cached */
		/* verify that owner matches current sname */
		if(query_dname_compare(sname, rep->rrsets[i]->rk.dname) != 0){
			/* cname chain broken */
			return 0;
		}
		/* if this is a cname; move on */
		if(t == LDNS_RR_TYPE_CNAME) {
			get_cname_target(rep->rrsets[i], &sname, &snamelen);
		}
	}
	return 1;
}

int
reply_all_rrsets_secure(struct reply_info* rep)
{
	size_t i;
	for(i=0; i<rep->rrset_count; i++) {
		if( ((struct packed_rrset_data*)rep->rrsets[i]->entry.data)
			->security != sec_status_secure )
		return 0;
	}
	return 1;
}

struct reply_info*
parse_reply_in_temp_region(sldns_buffer* pkt, struct regional* region,
	struct query_info* qi)
{
	struct reply_info* rep;
	struct msg_parse* msg;
	if(!(msg = regional_alloc(region, sizeof(*msg)))) {
		return NULL;
	}
	memset(msg, 0, sizeof(*msg));
	sldns_buffer_set_position(pkt, 0);
	if(parse_packet(pkt, msg, region) != 0){
		return 0;
	}
	if(!parse_create_msg(pkt, msg, NULL, qi, &rep, region)) {
		return 0;
	}
	return rep;
}

int edns_opt_list_append_ede(struct edns_option** list, struct regional* region,
	sldns_ede_code code, const char *txt)
{
	struct edns_option** prevp;
	struct edns_option* opt;
	size_t txt_len = txt ? strlen(txt) : 0;

	/* allocate new element */
	opt = (struct edns_option*)regional_alloc(region, sizeof(*opt));
	if(!opt)
		return 0;
	opt->next = NULL;
	opt->opt_code = LDNS_EDNS_EDE;
	opt->opt_len = txt_len + sizeof(uint16_t);
	opt->opt_data = regional_alloc(region, txt_len + sizeof(uint16_t));
	if(!opt->opt_data)
		return 0;
	sldns_write_uint16(opt->opt_data, (uint16_t)code);
	if (txt_len)
		memmove(opt->opt_data + 2, txt, txt_len);

	/* append at end of list */
	prevp = list;
	while(*prevp != NULL)
		prevp = &((*prevp)->next);
	verbose(VERB_ALGO, "attached EDE code: %d with message: %s", code, (txt?txt:"\"\""));
	*prevp = opt;
	return 1;
}

int edns_opt_list_append_keepalive(struct edns_option** list, int msec,
	struct regional* region)
{
	uint8_t data[2]; /* For keepalive value */
	data[0] = (uint8_t)((msec >> 8) & 0xff);
	data[1] = (uint8_t)(msec & 0xff);
	return edns_opt_list_append(list, LDNS_EDNS_KEEPALIVE, sizeof(data),
		data, region);
}

int edns_opt_list_append(struct edns_option** list, uint16_t code, size_t len,
	uint8_t* data, struct regional* region)
{
	struct edns_option** prevp;
	struct edns_option* opt;

	/* allocate new element */
	opt = (struct edns_option*)regional_alloc(region, sizeof(*opt));
	if(!opt)
		return 0;
	opt->next = NULL;
	opt->opt_code = code;
	opt->opt_len = len;
	opt->opt_data = NULL;
	if(len > 0) {
		opt->opt_data = regional_alloc_init(region, data, len);
		if(!opt->opt_data)
			return 0;
	}

	/* append at end of list */
	prevp = list;
	while(*prevp != NULL) {
		prevp = &((*prevp)->next);
	}
	*prevp = opt;
	return 1;
}

int edns_opt_list_remove(struct edns_option** list, uint16_t code)
{
	/* The list should already be allocated in a region. Freeing the
	 * allocated space in a region is not possible. We just unlink the
	 * required elements and they will be freed together with the region. */

	struct edns_option* prev;
	struct edns_option* curr;
	if(!list || !(*list)) return 0;

	/* Unlink and repoint if the element(s) are first in list */
	while(list && *list && (*list)->opt_code == code) {
		*list = (*list)->next;
	}

	if(!list || !(*list)) return 1;
	/* Unlink elements and reattach the list */
	prev = *list;
	curr = (*list)->next;
	while(curr != NULL) {
		if(curr->opt_code == code) {
			prev->next = curr->next;
			curr = curr->next;
		} else {
			prev = curr;
			curr = curr->next;
		}
	}
	return 1;
}

static int inplace_cb_reply_call_generic(
    struct inplace_cb* callback_list, enum inplace_cb_list_type type,
	struct query_info* qinfo, struct module_qstate* qstate,
	struct reply_info* rep, int rcode, struct edns_data* edns,
	struct comm_reply* repinfo, struct regional* region,
	struct timeval* start_time)
{
	struct inplace_cb* cb;
	struct edns_option* opt_list_out = NULL;
#if defined(EXPORT_ALL_SYMBOLS)
	(void)type; /* param not used when fptr_ok disabled */
#endif
	if(qstate)
		opt_list_out = qstate->edns_opts_front_out;
	for(cb=callback_list; cb; cb=cb->next) {
		fptr_ok(fptr_whitelist_inplace_cb_reply_generic(
			(inplace_cb_reply_func_type*)cb->cb, type));
		(void)(*(inplace_cb_reply_func_type*)cb->cb)(qinfo, qstate, rep,
			rcode, edns, &opt_list_out, repinfo, region, start_time, cb->id, cb->cb_arg);
	}
	edns->opt_list_inplace_cb_out = opt_list_out;
	return 1;
}

int inplace_cb_reply_call(struct module_env* env, struct query_info* qinfo,
	struct module_qstate* qstate, struct reply_info* rep, int rcode,
	struct edns_data* edns, struct comm_reply* repinfo, struct regional* region,
	struct timeval* start_time)
{
	return inplace_cb_reply_call_generic(
		env->inplace_cb_lists[inplace_cb_reply], inplace_cb_reply, qinfo,
		qstate, rep, rcode, edns, repinfo, region, start_time);
}

int inplace_cb_reply_cache_call(struct module_env* env,
	struct query_info* qinfo, struct module_qstate* qstate,
	struct reply_info* rep, int rcode, struct edns_data* edns,
	struct comm_reply* repinfo, struct regional* region,
	struct timeval* start_time)
{
	return inplace_cb_reply_call_generic(
		env->inplace_cb_lists[inplace_cb_reply_cache], inplace_cb_reply_cache,
		qinfo, qstate, rep, rcode, edns, repinfo, region, start_time);
}

int inplace_cb_reply_local_call(struct module_env* env,
	struct query_info* qinfo, struct module_qstate* qstate,
	struct reply_info* rep, int rcode, struct edns_data* edns,
	struct comm_reply* repinfo, struct regional* region,
	struct timeval* start_time)
{
	return inplace_cb_reply_call_generic(
		env->inplace_cb_lists[inplace_cb_reply_local], inplace_cb_reply_local,
		qinfo, qstate, rep, rcode, edns, repinfo, region, start_time);
}

int inplace_cb_reply_servfail_call(struct module_env* env,
	struct query_info* qinfo, struct module_qstate* qstate,
	struct reply_info* rep, int rcode, struct edns_data* edns,
	struct comm_reply* repinfo, struct regional* region,
	struct timeval* start_time)
{
	/* We are going to servfail. Remove any potential edns options. */
	if(qstate)
		qstate->edns_opts_front_out = NULL;
	return inplace_cb_reply_call_generic(
		env->inplace_cb_lists[inplace_cb_reply_servfail],
		inplace_cb_reply_servfail, qinfo, qstate, rep, rcode, edns, repinfo,
		region, start_time);
}

int inplace_cb_query_call(struct module_env* env, struct query_info* qinfo,
	uint16_t flags, struct sockaddr_storage* addr, socklen_t addrlen,
	uint8_t* zone, size_t zonelen, struct module_qstate* qstate,
	struct regional* region)
{
	struct inplace_cb* cb = env->inplace_cb_lists[inplace_cb_query];
	for(; cb; cb=cb->next) {
		fptr_ok(fptr_whitelist_inplace_cb_query(
			(inplace_cb_query_func_type*)cb->cb));
		(void)(*(inplace_cb_query_func_type*)cb->cb)(qinfo, flags,
			qstate, addr, addrlen, zone, zonelen, region,
			cb->id, cb->cb_arg);
	}
	return 1;
}

int inplace_cb_edns_back_parsed_call(struct module_env* env,
	struct module_qstate* qstate)
{
	struct inplace_cb* cb =
		env->inplace_cb_lists[inplace_cb_edns_back_parsed];
	for(; cb; cb=cb->next) {
		fptr_ok(fptr_whitelist_inplace_cb_edns_back_parsed(
			(inplace_cb_edns_back_parsed_func_type*)cb->cb));
		(void)(*(inplace_cb_edns_back_parsed_func_type*)cb->cb)(qstate,
			cb->id, cb->cb_arg);
	}
	return 1;
}

int inplace_cb_query_response_call(struct module_env* env,
	struct module_qstate* qstate, struct dns_msg* response) {
	struct inplace_cb* cb =
		env->inplace_cb_lists[inplace_cb_query_response];
	for(; cb; cb=cb->next) {
		fptr_ok(fptr_whitelist_inplace_cb_query_response(
			(inplace_cb_query_response_func_type*)cb->cb));
		(void)(*(inplace_cb_query_response_func_type*)cb->cb)(qstate,
			response, cb->id, cb->cb_arg);
	}
	return 1;
}

struct edns_option* edns_opt_copy_region(struct edns_option* list,
	struct regional* region)
{
	struct edns_option* result = NULL, *cur = NULL, *s;
	while(list) {
		/* copy edns option structure */
		s = regional_alloc_init(region, list, sizeof(*list));
		if(!s) return NULL;
		s->next = NULL;

		/* copy option data */
		if(s->opt_data) {
			s->opt_data = regional_alloc_init(region, s->opt_data,
				s->opt_len);
			if(!s->opt_data)
				return NULL;
		}

		/* link into list */
		if(cur)
			cur->next = s;
		else	result = s;
		cur = s;

		/* examine next element */
		list = list->next;
	}
	return result;
}

struct edns_option* edns_opt_copy_filter_region(struct edns_option* list,
	uint16_t* filter_list, size_t filter_list_len, struct regional* region)
{
	struct edns_option* result = NULL, *cur = NULL, *s;
	size_t i;
	while(list) {
		for(i=0; i<filter_list_len; i++)
			if(filter_list[i] == list->opt_code) goto found;
		if(i == filter_list_len) goto next;
found:
		/* copy edns option structure */
		s = regional_alloc_init(region, list, sizeof(*list));
		if(!s) return NULL;
		s->next = NULL;

		/* copy option data */
		if(s->opt_data) {
			s->opt_data = regional_alloc_init(region, s->opt_data,
				s->opt_len);
			if(!s->opt_data)
				return NULL;
		}

		/* link into list */
		if(cur)
			cur->next = s;
		else	result = s;
		cur = s;

next:
		/* examine next element */
		list = list->next;
	}
	return result;
}

int edns_opt_compare(struct edns_option* p, struct edns_option* q)
{
	if(!p && !q) return 0;
	if(!p) return -1;
	if(!q) return 1;
	log_assert(p && q);
	if(p->opt_code != q->opt_code)
		return (int)q->opt_code - (int)p->opt_code;
	if(p->opt_len != q->opt_len)
		return (int)q->opt_len - (int)p->opt_len;
	if(p->opt_len != 0)
		return memcmp(p->opt_data, q->opt_data, p->opt_len);
	return 0;
}

int edns_opt_list_compare(struct edns_option* p, struct edns_option* q)
{
	int r;
	while(p && q) {
		r = edns_opt_compare(p, q);
		if(r != 0)
			return r;
		p = p->next;
		q = q->next;
	}
	if(p || q) {
		/* uneven length lists */
		if(p) return 1;
		if(q) return -1;
	}
	return 0;
}

void edns_opt_list_free(struct edns_option* list)
{
	struct edns_option* n;
	while(list) {
		free(list->opt_data);
		n = list->next;
		free(list);
		list = n;
	}
}

struct edns_option* edns_opt_copy_alloc(struct edns_option* list)
{
	struct edns_option* result = NULL, *cur = NULL, *s;
	while(list) {
		/* copy edns option structure */
		s = memdup(list, sizeof(*list));
		if(!s) {
			edns_opt_list_free(result);
			return NULL;
		}
		s->next = NULL;

		/* copy option data */
		if(s->opt_data) {
			s->opt_data = memdup(s->opt_data, s->opt_len);
			if(!s->opt_data) {
				free(s);
				edns_opt_list_free(result);
				return NULL;
			}
		}

		/* link into list */
		if(cur)
			cur->next = s;
		else	result = s;
		cur = s;

		/* examine next element */
		list = list->next;
	}
	return result;
}

struct edns_option* edns_opt_list_find(struct edns_option* list, uint16_t code)
{
	struct edns_option* p;
	for(p=list; p; p=p->next) {
		if(p->opt_code == code)
			return p;
	}
	return NULL;
}