/*
 * daemon/worker.c - worker that handles a pending list of requests.
 *
 * 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 implements the worker that handles callbacks on events, for
 * pending requests.
 */
#include "config.h"
#include "util/log.h"
#include "util/net_help.h"
#include "util/random.h"
#include "daemon/worker.h"
#include "daemon/daemon.h"
#include "daemon/remote.h"
#include "daemon/acl_list.h"
#include "util/netevent.h"
#include "util/config_file.h"
#include "util/module.h"
#include "util/regional.h"
#include "util/storage/slabhash.h"
#include "services/listen_dnsport.h"
#include "services/outside_network.h"
#include "services/outbound_list.h"
#include "services/cache/rrset.h"
#include "services/cache/infra.h"
#include "services/cache/dns.h"
#include "services/authzone.h"
#include "services/mesh.h"
#include "services/localzone.h"
#include "services/rpz.h"
#include "util/data/msgparse.h"
#include "util/data/msgencode.h"
#include "util/data/dname.h"
#include "util/fptr_wlist.h"
#include "util/proxy_protocol.h"
#include "util/tube.h"
#include "util/edns.h"
#include "util/timeval_func.h"
#include "iterator/iter_fwd.h"
#include "iterator/iter_hints.h"
#include "iterator/iter_utils.h"
#include "validator/autotrust.h"
#include "validator/val_anchor.h"
#include "respip/respip.h"
#include "libunbound/context.h"
#include "libunbound/libworker.h"
#include "sldns/sbuffer.h"
#include "sldns/wire2str.h"
#include "util/shm_side/shm_main.h"
#include "dnscrypt/dnscrypt.h"
#include "dnstap/dtstream.h"

#ifdef HAVE_SYS_TYPES_H
#  include <sys/types.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#include <signal.h>
#ifdef UB_ON_WINDOWS
#include "winrc/win_svc.h"
#endif

/** Size of an UDP datagram */
#define NORMAL_UDP_SIZE 512 /* bytes */
/** ratelimit for error responses */
#define ERROR_RATELIMIT 100 /* qps */

/**
 * seconds to add to prefetch leeway.  This is a TTL that expires old rrsets
 * earlier than they should in order to put the new update into the cache.
 * This additional value is to make sure that if not all TTLs are equal in
 * the message to be updated(and replaced), that rrsets with up to this much
 * extra TTL are also replaced.  This means that the resulting new message
 * will have (most likely) this TTL at least, avoiding very small 'split
 * second' TTLs due to operators choosing relative primes for TTLs (or so).
 * Also has to be at least one to break ties (and overwrite cached entry).
 */
#define PREFETCH_EXPIRY_ADD 60

/** Report on memory usage by this thread and global */
static void
worker_mem_report(struct worker* ATTR_UNUSED(worker),
        struct serviced_query* ATTR_UNUSED(cur_serv))
{
#ifdef UNBOUND_ALLOC_STATS
        /* measure memory leakage */
        extern size_t unbound_mem_alloc, unbound_mem_freed;
        /* debug func in validator module */
        size_t total, front, back, mesh, msg, rrset, infra, ac, superac;
        size_t me, iter, val, anch;
        int i;
#ifdef CLIENT_SUBNET
        size_t subnet = 0;
#endif /* CLIENT_SUBNET */
        if(verbosity < VERB_ALGO)
                return;
        front = listen_get_mem(worker->front);
        back = outnet_get_mem(worker->back);
        msg = slabhash_get_mem(worker->env.msg_cache);
        rrset = slabhash_get_mem(&worker->env.rrset_cache->table);
        infra = infra_get_mem(worker->env.infra_cache);
        mesh = mesh_get_mem(worker->env.mesh);
        ac = alloc_get_mem(worker->alloc);
        superac = alloc_get_mem(&worker->daemon->superalloc);
        anch = anchors_get_mem(worker->env.anchors);
        iter = 0;
        val = 0;
        for(i=0; i<worker->env.mesh->mods.num; i++) {
                fptr_ok(fptr_whitelist_mod_get_mem(worker->env.mesh->
                        mods.mod[i]->get_mem));
                if(strcmp(worker->env.mesh->mods.mod[i]->name, "validator")==0)
                        val += (*worker->env.mesh->mods.mod[i]->get_mem)
                                (&worker->env, i);
#ifdef CLIENT_SUBNET
                else if(strcmp(worker->env.mesh->mods.mod[i]->name,
                        "subnetcache")==0)
                        subnet += (*worker->env.mesh->mods.mod[i]->get_mem)
                                (&worker->env, i);
#endif /* CLIENT_SUBNET */
                else    iter += (*worker->env.mesh->mods.mod[i]->get_mem)
                                (&worker->env, i);
        }
        me = sizeof(*worker) + sizeof(*worker->base) + sizeof(*worker->comsig)
                + comm_point_get_mem(worker->cmd_com)
                + sizeof(worker->rndstate)
                + regional_get_mem(worker->scratchpad)
                + sizeof(*worker->env.scratch_buffer)
                + sldns_buffer_capacity(worker->env.scratch_buffer);
        if(worker->daemon->env->fwds)
                log_info("forwards=%u", (unsigned)forwards_get_mem(worker->env.fwds));
        if(worker->daemon->env->hints)
                log_info("hints=%u", (unsigned)hints_get_mem(worker->env.hints));
        if(worker->thread_num == 0)
                me += acl_list_get_mem(worker->daemon->acl);
        if(cur_serv) {
                me += serviced_get_mem(cur_serv);
        }
        total = front+back+mesh+msg+rrset+infra+iter+val+ac+superac+me;
#ifdef CLIENT_SUBNET
        total += subnet;
        log_info("Memory conditions: %u front=%u back=%u mesh=%u msg=%u "
                "rrset=%u infra=%u iter=%u val=%u subnet=%u anchors=%u "
                "alloccache=%u globalalloccache=%u me=%u",
                (unsigned)total, (unsigned)front, (unsigned)back,
                (unsigned)mesh, (unsigned)msg, (unsigned)rrset, (unsigned)infra,
                (unsigned)iter, (unsigned)val,
                (unsigned)subnet, (unsigned)anch, (unsigned)ac,
                (unsigned)superac, (unsigned)me);
#else /* no CLIENT_SUBNET */
        log_info("Memory conditions: %u front=%u back=%u mesh=%u msg=%u "
                "rrset=%u infra=%u iter=%u val=%u anchors=%u "
                "alloccache=%u globalalloccache=%u me=%u",
                (unsigned)total, (unsigned)front, (unsigned)back,
                (unsigned)mesh, (unsigned)msg, (unsigned)rrset,
                (unsigned)infra, (unsigned)iter, (unsigned)val, (unsigned)anch,
                (unsigned)ac, (unsigned)superac, (unsigned)me);
#endif /* CLIENT_SUBNET */
        log_info("Total heap memory estimate: %u  total-alloc: %u  "
                "total-free: %u", (unsigned)total,
                (unsigned)unbound_mem_alloc, (unsigned)unbound_mem_freed);
#else /* no UNBOUND_ALLOC_STATS */
        size_t val = 0;
#ifdef CLIENT_SUBNET
        size_t subnet = 0;
#endif /* CLIENT_SUBNET */
        int i;
        if(verbosity < VERB_QUERY)
                return;
        for(i=0; i<worker->env.mesh->mods.num; i++) {
                fptr_ok(fptr_whitelist_mod_get_mem(worker->env.mesh->
                        mods.mod[i]->get_mem));
                if(strcmp(worker->env.mesh->mods.mod[i]->name, "validator")==0)
                        val += (*worker->env.mesh->mods.mod[i]->get_mem)
                                (&worker->env, i);
#ifdef CLIENT_SUBNET
                else if(strcmp(worker->env.mesh->mods.mod[i]->name,
                        "subnetcache")==0)
                        subnet += (*worker->env.mesh->mods.mod[i]->get_mem)
                                (&worker->env, i);
#endif /* CLIENT_SUBNET */
        }
#ifdef CLIENT_SUBNET
        verbose(VERB_QUERY, "cache memory msg=%u rrset=%u infra=%u val=%u "
                "subnet=%u",
                (unsigned)slabhash_get_mem(worker->env.msg_cache),
                (unsigned)slabhash_get_mem(&worker->env.rrset_cache->table),
                (unsigned)infra_get_mem(worker->env.infra_cache),
                (unsigned)val, (unsigned)subnet);
#else /* no CLIENT_SUBNET */
        verbose(VERB_QUERY, "cache memory msg=%u rrset=%u infra=%u val=%u",
                (unsigned)slabhash_get_mem(worker->env.msg_cache),
                (unsigned)slabhash_get_mem(&worker->env.rrset_cache->table),
                (unsigned)infra_get_mem(worker->env.infra_cache),
                (unsigned)val);
#endif /* CLIENT_SUBNET */
#endif /* UNBOUND_ALLOC_STATS */
}

void
worker_send_cmd(struct worker* worker, enum worker_commands cmd)
{
        uint32_t c = (uint32_t)htonl(cmd);
        if(!tube_write_msg(worker->cmd, (uint8_t*)&c, sizeof(c), 0)) {
                log_err("worker send cmd %d failed", (int)cmd);
        }
}

int
worker_handle_service_reply(struct comm_point* c, void* arg, int error,
        struct comm_reply* reply_info)
{
        struct outbound_entry* e = (struct outbound_entry*)arg;
        struct worker* worker = e->qstate->env->worker;
        struct serviced_query *sq = e->qsent;

        verbose(VERB_ALGO, "worker svcd callback for qstate %p", e->qstate);
        if(error != 0) {
                mesh_report_reply(worker->env.mesh, e, reply_info, error);
                worker_mem_report(worker, sq);
                return 0;
        }
        /* sanity check. */
        if(sldns_buffer_limit(c->buffer) < LDNS_HEADER_SIZE
                || !LDNS_QR_WIRE(sldns_buffer_begin(c->buffer))
                || LDNS_OPCODE_WIRE(sldns_buffer_begin(c->buffer)) !=
                        LDNS_PACKET_QUERY
                || LDNS_QDCOUNT(sldns_buffer_begin(c->buffer)) > 1) {
                /* error becomes timeout for the module as if this reply
                 * never arrived. */
                verbose(VERB_ALGO, "worker: bad reply handled as timeout");
                mesh_report_reply(worker->env.mesh, e, reply_info,
                        NETEVENT_TIMEOUT);
                worker_mem_report(worker, sq);
                return 0;
        }
        mesh_report_reply(worker->env.mesh, e, reply_info, NETEVENT_NOERROR);
        worker_mem_report(worker, sq);
        return 0;
}

/** ratelimit error replies
 * @param worker: the worker struct with ratelimit counter
 * @param err: error code that would be wanted.
 * @return value of err if okay, or -1 if it should be discarded instead.
 */
static int
worker_err_ratelimit(struct worker* worker, int err)
{
        if(worker->err_limit_time == *worker->env.now) {
                /* see if limit is exceeded for this second */
                if(worker->err_limit_count++ > ERROR_RATELIMIT)
                        return -1;
        } else {
                /* new second, new limits */
                worker->err_limit_time = *worker->env.now;
                worker->err_limit_count = 1;
        }
        return err;
}

/**
 * Reply with an error.
 * This reply includes the qname if it has been parsed.
 * For error ratelimiting, the err ratelimit routine should be checked
 * beforehand. The reply is without EDNS, and copies RD and sets QR flag.
 * @param pkt: the packet buffer from the comm point.
 * @param err: the error code that would be wanted.
 * @param qname_len: 0 if not parsed, and the qname length in packet.
 */
static void
query_error(sldns_buffer* pkt, int err, size_t qname_len)
{
        /* Preserve the RD flag.
         * The CD flag must be cleared in authoritative answers,
         * also the AD flag need not be copied into answers.
         * The other flags need not be copied into the answer. */
        sldns_buffer_write_u16_at(pkt, 2,
                sldns_buffer_read_u16_at(pkt, 2)&0x0100U);
        LDNS_QR_SET(sldns_buffer_begin(pkt)); /* Set QR flag. */
        LDNS_RCODE_SET(sldns_buffer_begin(pkt), err); /* Set rcode */

        if(qname_len && LDNS_QDCOUNT(sldns_buffer_begin(pkt))>=1 &&
                qname_len <= LDNS_MAX_DOMAINLEN) {
                /* Copy query into the answer. */
                LDNS_QDCOUNT_SET(sldns_buffer_begin(pkt), 1);
                sldns_buffer_set_position(pkt, LDNS_HEADER_SIZE +
                        qname_len + 2 /* type */ + 2 /* class */ );
        } else {
                /* No query section in answer. */
                LDNS_QDCOUNT_SET(sldns_buffer_begin(pkt), 0);
                sldns_buffer_set_position(pkt, LDNS_HEADER_SIZE);
        }
        LDNS_ANCOUNT_SET(sldns_buffer_begin(pkt), 0);
        LDNS_NSCOUNT_SET(sldns_buffer_begin(pkt), 0);
        LDNS_ARCOUNT_SET(sldns_buffer_begin(pkt), 0);
        sldns_buffer_flip(pkt);
}

/**
 * Structure holding the result of the worker_check_request function.
 * Based on configuration it could be called up to four times; ideally should
 * be called once.
 */
struct check_request_result {
        int checked;
        int value;
};
/** check request sanity.
 * @param pkt: the wire packet to examine for sanity.
 * @param worker: parameters for checking.
 * @param out: struct to update with the result.
*/
static void
worker_check_request(sldns_buffer* pkt, struct worker* worker,
        struct check_request_result* out)
{
        if(out->checked) return;
        out->checked = 1;
        if(sldns_buffer_limit(pkt) < LDNS_HEADER_SIZE) {
                verbose(VERB_QUERY, "request too short, discarded");
                out->value = -1;
                return;
        }
        if(sldns_buffer_limit(pkt) > NORMAL_UDP_SIZE &&
                worker->daemon->cfg->harden_large_queries) {
                verbose(VERB_QUERY, "request too large, discarded");
                out->value = -1;
                return;
        }
        if(LDNS_QR_WIRE(sldns_buffer_begin(pkt))) {
                verbose(VERB_QUERY, "request has QR bit on, discarded");
                out->value = -1;
                return;
        }
        if(LDNS_TC_WIRE(sldns_buffer_begin(pkt))) {
                verbose(VERB_QUERY, "request bad, has TC bit on");
                out->value = worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
                return;
        }
        if(LDNS_OPCODE_WIRE(sldns_buffer_begin(pkt)) != LDNS_PACKET_QUERY &&
                LDNS_OPCODE_WIRE(sldns_buffer_begin(pkt)) != LDNS_PACKET_NOTIFY) {
                verbose(VERB_QUERY, "request unknown opcode %d",
                        LDNS_OPCODE_WIRE(sldns_buffer_begin(pkt)));
                out->value = worker_err_ratelimit(worker, LDNS_RCODE_NOTIMPL);
                return;
        }
        if(LDNS_QDCOUNT(sldns_buffer_begin(pkt)) != 1) {
                verbose(VERB_QUERY, "request wrong nr qd=%d",
                        LDNS_QDCOUNT(sldns_buffer_begin(pkt)));
                out->value = worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
                return;
        }
        if(LDNS_ANCOUNT(sldns_buffer_begin(pkt)) != 0 &&
                (LDNS_ANCOUNT(sldns_buffer_begin(pkt)) != 1 ||
                LDNS_OPCODE_WIRE(sldns_buffer_begin(pkt)) != LDNS_PACKET_NOTIFY)) {
                verbose(VERB_QUERY, "request wrong nr an=%d",
                        LDNS_ANCOUNT(sldns_buffer_begin(pkt)));
                out->value = worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
                return;
        }
        if(LDNS_NSCOUNT(sldns_buffer_begin(pkt)) != 0) {
                verbose(VERB_QUERY, "request wrong nr ns=%d",
                        LDNS_NSCOUNT(sldns_buffer_begin(pkt)));
                out->value = worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
                return;
        }
        if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) > 1) {
                verbose(VERB_QUERY, "request wrong nr ar=%d",
                        LDNS_ARCOUNT(sldns_buffer_begin(pkt)));
                out->value = worker_err_ratelimit(worker, LDNS_RCODE_FORMERR);
                return;
        }
        out->value = 0;
        return;
}

/**
 * Send fast-reload acknowledgement to the mainthread in one byte.
 * This signals that this worker has received the previous command.
 * The worker is waiting if that is after a reload_stop command.
 * Or the worker has briefly processed the event itself, and in doing so
 * released data pointers to old config, after a reload_poll command.
 */
static void
worker_send_reload_ack(struct worker* worker)
{
        /* If this is clipped to 8 bits because thread_num>255, then that
         * is not a problem, the receiver counts the number of bytes received.
         * The number is informative only. */
        uint8_t c = (uint8_t)worker->thread_num;
        ssize_t ret;
        while(1) {
                ret = send(worker->daemon->fast_reload_thread->commreload[1],
                        (void*)&c, 1, 0);
                if(ret == -1) {
                        if(
#ifndef USE_WINSOCK
                                errno == EINTR || errno == EAGAIN
#  ifdef EWOULDBLOCK
                                || errno == EWOULDBLOCK
#  endif
#else
                                WSAGetLastError() == WSAEINTR ||
                                WSAGetLastError() == WSAEINPROGRESS ||
                                WSAGetLastError() == WSAEWOULDBLOCK
#endif
                                )
                                continue; /* Try again. */
                        log_err("worker reload ack reply: send failed: %s",
                                sock_strerror(errno));
                        break;
                }
                break;
        }
}

/** stop and wait to resume the worker */
static void
worker_stop_and_wait(struct worker* worker)
{
        uint8_t* buf = NULL;
        uint32_t len = 0, cmd;
        worker_send_reload_ack(worker);
        /* wait for reload */
        if(!tube_read_msg(worker->cmd, &buf, &len, 0)) {
                log_err("worker reload read reply failed");
                return;
        }
        if(len != sizeof(uint32_t)) {
                log_err("worker reload reply, bad control msg length %d",
                        (int)len);
                free(buf);
                return;
        }
        cmd = sldns_read_uint32(buf);
        free(buf);
        if(cmd == worker_cmd_quit) {
                /* quit anyway */
                verbose(VERB_ALGO, "reload reply, control cmd quit");
                comm_base_exit(worker->base);
                return;
        }
        if(cmd != worker_cmd_reload_start) {
                log_err("worker reload reply, wrong reply command");
        }
        if(worker->daemon->fast_reload_drop_mesh) {
                verbose(VERB_ALGO, "worker: drop mesh queries after reload");
                mesh_delete_all(worker->env.mesh);
        }
        fast_reload_worker_pickup_changes(worker);
        worker_send_reload_ack(worker);
        verbose(VERB_ALGO, "worker resume after reload");
}

void
worker_handle_control_cmd(struct tube* ATTR_UNUSED(tube), uint8_t* msg,
        size_t len, int error, void* arg)
{
        struct worker* worker = (struct worker*)arg;
        enum worker_commands cmd;
        if(error != NETEVENT_NOERROR) {
                free(msg);
                if(error == NETEVENT_CLOSED)
                        comm_base_exit(worker->base);
                else    log_info("control event: %d", error);
                return;
        }
        if(len != sizeof(uint32_t)) {
                fatal_exit("bad control msg length %d", (int)len);
        }
        cmd = sldns_read_uint32(msg);
        free(msg);
        switch(cmd) {
        case worker_cmd_quit:
                verbose(VERB_ALGO, "got control cmd quit");
                comm_base_exit(worker->base);
                break;
        case worker_cmd_stats:
                verbose(VERB_ALGO, "got control cmd stats");
                server_stats_reply(worker, 1);
                break;
        case worker_cmd_stats_noreset:
                verbose(VERB_ALGO, "got control cmd stats_noreset");
                server_stats_reply(worker, 0);
                break;
        case worker_cmd_remote:
                verbose(VERB_ALGO, "got control cmd remote");
                daemon_remote_exec(worker);
                break;
        case worker_cmd_reload_stop:
                verbose(VERB_ALGO, "got control cmd reload_stop");
                worker_stop_and_wait(worker);
                break;
        case worker_cmd_reload_poll:
                verbose(VERB_ALGO, "got control cmd reload_poll");
                fast_reload_worker_pickup_changes(worker);
                worker_send_reload_ack(worker);
                break;
        default:
                log_err("bad command %d", (int)cmd);
                break;
        }
}

/** check if a delegation is secure */
static enum sec_status
check_delegation_secure(struct reply_info *rep)
{
        /* return smallest security status */
        size_t i;
        enum sec_status sec = sec_status_secure;
        enum sec_status s;
        size_t num = rep->an_numrrsets + rep->ns_numrrsets;
        /* check if answer and authority are OK */
        for(i=0; i<num; i++) {
                s = ((struct packed_rrset_data*)rep->rrsets[i]->entry.data)
                        ->security;
                if(s < sec)
                        sec = s;
        }
        /* in additional, only unchecked triggers revalidation */
        for(i=num; i<rep->rrset_count; i++) {
                s = ((struct packed_rrset_data*)rep->rrsets[i]->entry.data)
                        ->security;
                if(s == sec_status_unchecked)
                        return s;
        }
        return sec;
}

/** remove nonsecure from a delegation referral additional section */
static void
deleg_remove_nonsecure_additional(struct reply_info* rep)
{
        /* we can simply edit it, since we are working in the scratch region */
        size_t i;
        enum sec_status s;

        for(i = rep->an_numrrsets+rep->ns_numrrsets; i<rep->rrset_count; i++) {
                s = ((struct packed_rrset_data*)rep->rrsets[i]->entry.data)
                        ->security;
                if(s != sec_status_secure) {
                        memmove(rep->rrsets+i, rep->rrsets+i+1,
                                sizeof(struct ub_packed_rrset_key*)*
                                (rep->rrset_count - i - 1));
                        rep->ar_numrrsets--;
                        rep->rrset_count--;
                        i--;
                }
        }
}

/** answer nonrecursive query from the cache */
static int
answer_norec_from_cache(struct worker* worker, struct query_info* qinfo,
        uint16_t id, uint16_t flags, struct comm_reply* repinfo,
        struct edns_data* edns)
{
        /* for a nonrecursive query return either:
         *      o an error (servfail; we try to avoid this)
         *      o a delegation (closest we have; this routine tries that)
         *      o the answer (checked by answer_from_cache)
         *
         * So, grab a delegation from the rrset cache.
         * Then check if it needs validation, if so, this routine fails,
         * so that iterator can prime and validator can verify rrsets.
         */
        uint16_t udpsize = edns->udp_size;
        int secure = 0;
        time_t timenow = *worker->env.now;
        int has_cd_bit = (flags&BIT_CD);
        int must_validate = (!has_cd_bit || worker->env.cfg->ignore_cd)
                && worker->env.need_to_validate;
        struct dns_msg *msg = NULL;
        struct delegpt *dp;

        dp = dns_cache_find_delegation(&worker->env, qinfo->qname,
                qinfo->qname_len, qinfo->qtype, qinfo->qclass,
                worker->scratchpad, &msg, timenow, 0, NULL, 0);
        if(!dp) { /* no delegation, need to reprime */
                return 0;
        }
        /* In case we have a local alias, copy it into the delegation message.
         * Shallow copy should be fine, as we'll be done with msg in this
         * function. */
        msg->qinfo.local_alias = qinfo->local_alias;
        if(must_validate) {
                switch(check_delegation_secure(msg->rep)) {
                case sec_status_unchecked:
                        /* some rrsets have not been verified yet, go and
                         * let validator do that */
                        return 0;
                case sec_status_bogus:
                case sec_status_secure_sentinel_fail:
                        /* some rrsets are bogus, reply servfail */
                        edns->edns_version = EDNS_ADVERTISED_VERSION;
                        edns->udp_size = EDNS_ADVERTISED_SIZE;
                        edns->ext_rcode = 0;
                        edns->bits &= EDNS_DO;
                        if(!inplace_cb_reply_servfail_call(&worker->env, qinfo, NULL,
                                msg->rep, LDNS_RCODE_SERVFAIL, edns, repinfo, worker->scratchpad,
                                worker->env.now_tv))
                                        return 0;
                        /* Attach the cached EDE (RFC8914) */
                        if(worker->env.cfg->ede &&
                                msg->rep->reason_bogus != LDNS_EDE_NONE) {
                                edns_opt_list_append_ede(&edns->opt_list_out,
                                        worker->scratchpad, msg->rep->reason_bogus,
                                        msg->rep->reason_bogus_str);
                        }
                        error_encode(repinfo->c->buffer, LDNS_RCODE_SERVFAIL,
                                &msg->qinfo, id, flags, edns);
                        if(worker->stats.extended) {
                                worker->stats.ans_bogus++;
                                worker->stats.ans_rcode[LDNS_RCODE_SERVFAIL]++;
                        }
                        return 1;
                case sec_status_secure:
                        /* all rrsets are secure */
                        /* remove non-secure rrsets from the add. section*/
                        if(worker->env.cfg->val_clean_additional)
                                deleg_remove_nonsecure_additional(msg->rep);
                        secure = 1;
                        break;
                case sec_status_indeterminate:
                case sec_status_insecure:
                default:
                        /* not secure */
                        secure = 0;
                        break;
                }
        }
        /* return this delegation from the cache */
        edns->edns_version = EDNS_ADVERTISED_VERSION;
        edns->udp_size = EDNS_ADVERTISED_SIZE;
        edns->ext_rcode = 0;
        edns->bits &= EDNS_DO;
        if(worker->env.cfg->disable_edns_do && (edns->bits & EDNS_DO))
                edns->edns_present = 0;
        if(!inplace_cb_reply_cache_call(&worker->env, qinfo, NULL, msg->rep,
                (int)(flags&LDNS_RCODE_MASK), edns, repinfo, worker->scratchpad,
                worker->env.now_tv))
                        return 0;
        msg->rep->flags |= BIT_QR|BIT_RA;
        /* Attach the cached EDE (RFC8914) if CD bit is set and the answer is
         * bogus. */
        if(worker->env.cfg->ede && has_cd_bit &&
                (check_delegation_secure(msg->rep) == sec_status_bogus ||
                check_delegation_secure(msg->rep) == sec_status_secure_sentinel_fail) &&
                msg->rep->reason_bogus != LDNS_EDE_NONE) {
                edns_opt_list_append_ede(&edns->opt_list_out,
                        worker->scratchpad, msg->rep->reason_bogus,
                        msg->rep->reason_bogus_str);
        }
        if(!reply_info_answer_encode(&msg->qinfo, msg->rep, id, flags,
                repinfo->c->buffer, 0, 1, worker->scratchpad,
                udpsize, edns, (int)(edns->bits & EDNS_DO), secure)) {
                if(!inplace_cb_reply_servfail_call(&worker->env, qinfo, NULL, NULL,
                        LDNS_RCODE_SERVFAIL, edns, repinfo, worker->scratchpad,
                        worker->env.now_tv))
                                edns->opt_list_inplace_cb_out = NULL;
                error_encode(repinfo->c->buffer, LDNS_RCODE_SERVFAIL,
                        &msg->qinfo, id, flags, edns);
        }
        if(worker->stats.extended) {
                if(secure) worker->stats.ans_secure++;
                server_stats_insrcode(&worker->stats, repinfo->c->buffer);
        }
        return 1;
}

/** Apply, if applicable, a response IP action to a cached answer.
 * If the answer is rewritten as a result of an action, '*encode_repp' will
 * point to the reply info containing the modified answer.  '*encode_repp' will
 * be intact otherwise.
 * It returns 1 on success, 0 otherwise. */
static int
apply_respip_action(struct worker* worker, const struct query_info* qinfo,
        struct respip_client_info* cinfo, struct reply_info* rep,
        struct sockaddr_storage* addr, socklen_t addrlen,
        struct ub_packed_rrset_key** alias_rrset,
        struct reply_info** encode_repp, struct auth_zones* az)
{
        struct respip_action_info actinfo = {0, 0, 0, 0, NULL, 0, NULL};
        actinfo.action = respip_none;

        if(qinfo->qtype != LDNS_RR_TYPE_A &&
                qinfo->qtype != LDNS_RR_TYPE_AAAA &&
                qinfo->qtype != LDNS_RR_TYPE_ANY)
                return 1;

        if(!respip_rewrite_reply(qinfo, cinfo, rep, encode_repp, &actinfo,
                alias_rrset, 0, worker->scratchpad, az, NULL,
                worker->env.views, worker->env.respip_set))
                return 0;

        /* xxx_deny actions mean dropping the reply, unless the original reply
         * was redirected to response-ip data. */
        if(actinfo.action == respip_always_deny ||
                ((actinfo.action == respip_deny ||
                actinfo.action == respip_inform_deny) &&
                *encode_repp == rep))
                *encode_repp = NULL;

        /* If address info is returned, it means the action should be an
         * 'inform' variant and the information should be logged. */
        if(actinfo.addrinfo) {
                respip_inform_print(&actinfo, qinfo->qname,
                        qinfo->qtype, qinfo->qclass, qinfo->local_alias,
                        addr, addrlen);

                if(worker->stats.extended && actinfo.rpz_used) {
                        if(actinfo.rpz_disabled)
                                worker->stats.rpz_action[RPZ_DISABLED_ACTION]++;
                        if(actinfo.rpz_cname_override)
                                worker->stats.rpz_action[RPZ_CNAME_OVERRIDE_ACTION]++;
                        else
                                worker->stats.rpz_action[
                                        respip_action_to_rpz_action(actinfo.action)]++;
                }
        }

        return 1;
}

/** answer query from the cache.
 * Normally, the answer message will be built in repinfo->c->buffer; if the
 * answer is supposed to be suppressed or the answer is supposed to be an
 * incomplete CNAME chain, the buffer is explicitly cleared to signal the
 * caller as such.  In the latter case *partial_rep will point to the incomplete
 * reply, and this function is (possibly) supposed to be called again with that
 * *partial_rep value to complete the chain.  In addition, if the query should
 * be completely dropped, '*need_drop' will be set to 1. */
static int
answer_from_cache(struct worker* worker, struct query_info* qinfo,
        struct respip_client_info* cinfo, int* need_drop, int* is_expired_answer,
        int* is_secure_answer, struct ub_packed_rrset_key** alias_rrset,
        struct reply_info** partial_repp,
        struct reply_info* rep, uint16_t id, uint16_t flags,
        struct comm_reply* repinfo, struct edns_data* edns)
{
        time_t timenow = *worker->env.now;
        uint16_t udpsize = edns->udp_size;
        struct reply_info* encode_rep = rep;
        struct reply_info* partial_rep = *partial_repp;
        int has_cd_bit = (flags&BIT_CD);
        int must_validate = (!has_cd_bit || worker->env.cfg->ignore_cd)
                && worker->env.need_to_validate;
        *partial_repp = NULL;  /* avoid accidental further pass */

        /* Check TTL */
        if(TTL_IS_EXPIRED(rep->ttl, timenow)) {
                /* Check if we need to serve expired now */
                if(worker->env.cfg->serve_expired &&
                        /* if serve-expired-client-timeout is set, serve
                         * an expired record without attempting recursion
                         * if the serve_expired_norec_ttl is set for the record
                         * as we know that recursion is currently failing. */
                        (!worker->env.cfg->serve_expired_client_timeout ||
                         timenow < rep->serve_expired_norec_ttl)
#ifdef USE_CACHEDB
                        && !(worker->env.cachedb_enabled &&
                          worker->env.cfg->cachedb_check_when_serve_expired)
#endif
                        ) {
                                if(!reply_info_can_answer_expired(rep, timenow))
                                        return 0;
                                if(!rrset_array_lock(rep->ref, rep->rrset_count, 0))
                                        return 0;
                                *is_expired_answer = 1;
                } else {
                        /* the rrsets may have been updated in the meantime.
                         * we will refetch the message format from the
                         * authoritative server
                         */
                        return 0;
                }
        } else {
                if(!rrset_array_lock(rep->ref, rep->rrset_count, timenow))
                        return 0;
        }
        /* locked and ids and ttls are OK. */

        /* check CNAME chain (if any) */
        if(rep->an_numrrsets > 0 && (rep->rrsets[0]->rk.type ==
                htons(LDNS_RR_TYPE_CNAME) || rep->rrsets[0]->rk.type ==
                htons(LDNS_RR_TYPE_DNAME))) {
                if(!reply_check_cname_chain(qinfo, rep)) {
                        /* cname chain invalid, redo iterator steps */
                        verbose(VERB_ALGO, "Cache reply: cname chain broken");
                        goto bail_out;
                }
        }
        /* check security status of the cached answer */
        if(must_validate && (rep->security == sec_status_bogus ||
                rep->security == sec_status_secure_sentinel_fail)) {
                /* BAD cached */
                edns->edns_version = EDNS_ADVERTISED_VERSION;
                edns->udp_size = EDNS_ADVERTISED_SIZE;
                edns->ext_rcode = 0;
                edns->bits &= EDNS_DO;
                if(worker->env.cfg->disable_edns_do && (edns->bits & EDNS_DO))
                        edns->edns_present = 0;
                if(!inplace_cb_reply_servfail_call(&worker->env, qinfo, NULL, rep,
                        LDNS_RCODE_SERVFAIL, edns, repinfo, worker->scratchpad,
                        worker->env.now_tv))
                        goto bail_out;
                /* Attach the cached EDE (RFC8914) */
                if(worker->env.cfg->ede && rep->reason_bogus != LDNS_EDE_NONE) {
                        edns_opt_list_append_ede(&edns->opt_list_out,
                                        worker->scratchpad, rep->reason_bogus,
                                        rep->reason_bogus_str);
                }
                error_encode(repinfo->c->buffer, LDNS_RCODE_SERVFAIL,
                        qinfo, id, flags, edns);
                rrset_array_unlock_touch(worker->env.rrset_cache,
                        worker->scratchpad, rep->ref, rep->rrset_count);
                if(worker->stats.extended) {
                        worker->stats.ans_bogus ++;
                        worker->stats.ans_rcode[LDNS_RCODE_SERVFAIL] ++;
                }
                return 1;
        } else if(rep->security == sec_status_unchecked && must_validate) {
                verbose(VERB_ALGO, "Cache reply: unchecked entry needs "
                        "validation");
                goto bail_out; /* need to validate cache entry first */
        } else if(rep->security == sec_status_secure) {
                if(reply_all_rrsets_secure(rep)) {
                        *is_secure_answer = 1;
                } else {
                        if(must_validate) {
                                verbose(VERB_ALGO, "Cache reply: secure entry"
                                        " changed status");
                                goto bail_out; /* rrset changed, re-verify */
                        }
                        *is_secure_answer = 0;
                }
        } else *is_secure_answer = 0;

        edns->edns_version = EDNS_ADVERTISED_VERSION;
        edns->udp_size = EDNS_ADVERTISED_SIZE;
        edns->ext_rcode = 0;
        edns->bits &= EDNS_DO;
        if(worker->env.cfg->disable_edns_do && (edns->bits & EDNS_DO))
                edns->edns_present = 0;
        *alias_rrset = NULL; /* avoid confusion if caller set it to non-NULL */
        if((worker->daemon->use_response_ip || worker->daemon->use_rpz) &&
                !partial_rep && !apply_respip_action(worker, qinfo, cinfo, rep,
                &repinfo->client_addr, repinfo->client_addrlen, alias_rrset,
                &encode_rep, worker->env.auth_zones)) {
                goto bail_out;
        } else if(partial_rep &&
                !respip_merge_cname(partial_rep, qinfo, rep, cinfo,
                must_validate, &encode_rep, worker->scratchpad,
                worker->env.auth_zones, worker->env.views,
                worker->env.respip_set)) {
                goto bail_out;
        }
        if(encode_rep != rep) {
                /* if rewritten, it can't be considered "secure" */
                *is_secure_answer = 0;
        }
        if(!encode_rep || *alias_rrset) {
                if(!encode_rep)
                        *need_drop = 1;
                else {
                        /* If a partial CNAME chain is found, we first need to
                         * make a copy of the reply in the scratchpad so we
                         * can release the locks and lookup the cache again. */
                        *partial_repp = reply_info_copy(encode_rep, NULL,
                                worker->scratchpad);
                        if(!*partial_repp)
                                goto bail_out;
                }
        } else {
                if(*is_expired_answer == 1 &&
                        worker->env.cfg->ede_serve_expired && worker->env.cfg->ede) {
                        EDNS_OPT_LIST_APPEND_EDE(&edns->opt_list_out,
                                worker->scratchpad, LDNS_EDE_STALE_ANSWER, "");
                }
                /* Attach the cached EDE (RFC8914) if CD bit is set and the
                 * answer is bogus. */
                if(*is_secure_answer == 0 &&
                        worker->env.cfg->ede && has_cd_bit &&
                        encode_rep->reason_bogus != LDNS_EDE_NONE) {
                        edns_opt_list_append_ede(&edns->opt_list_out,
                                worker->scratchpad, encode_rep->reason_bogus,
                                encode_rep->reason_bogus_str);
                }
                if(!inplace_cb_reply_cache_call(&worker->env, qinfo, NULL, encode_rep,
                        (int)(flags&LDNS_RCODE_MASK), edns, repinfo, worker->scratchpad,
                        worker->env.now_tv))
                        goto bail_out;
                if(!reply_info_answer_encode(qinfo, encode_rep, id, flags,
                        repinfo->c->buffer, timenow, 1, worker->scratchpad,
                        udpsize, edns, (int)(edns->bits & EDNS_DO),
                        *is_secure_answer)) {
                        if(!inplace_cb_reply_servfail_call(&worker->env, qinfo,
                                NULL, NULL, LDNS_RCODE_SERVFAIL, edns, repinfo,
                                worker->scratchpad, worker->env.now_tv))
                                        edns->opt_list_inplace_cb_out = NULL;
                        error_encode(repinfo->c->buffer, LDNS_RCODE_SERVFAIL,
                                qinfo, id, flags, edns);
                }
        }
        /* cannot send the reply right now, because blocking network syscall
         * is bad while holding locks. */
        rrset_array_unlock_touch(worker->env.rrset_cache, worker->scratchpad,
                rep->ref, rep->rrset_count);
        /* go and return this buffer to the client */
        return 1;

bail_out:
        rrset_array_unlock_touch(worker->env.rrset_cache,
                worker->scratchpad, rep->ref, rep->rrset_count);
        return 0;
}

/** Reply to client and perform prefetch to keep cache up to date. */
static void
reply_and_prefetch(struct worker* worker, struct query_info* qinfo,
        uint16_t flags, struct comm_reply* repinfo, time_t leeway, int noreply,
        int rpz_passthru, struct edns_option* opt_list)
{
        (void)opt_list;
        /* first send answer to client to keep its latency
         * as small as a cachereply */
        if(!noreply) {
                if(repinfo->c->tcp_req_info) {
                        sldns_buffer_copy(
                                repinfo->c->tcp_req_info->spool_buffer,
                                repinfo->c->buffer);
                }
                comm_point_send_reply(repinfo);
        }
        server_stats_prefetch(&worker->stats, worker);
#ifdef CLIENT_SUBNET
        /* Check if the subnet module is enabled. In that case pass over the
         * comm_reply information for ECS generation later. The mesh states are
         * unique when subnet is enabled. */
        if(modstack_find(&worker->env.mesh->mods, "subnetcache") != -1
                && worker->env.unique_mesh) {
                mesh_new_prefetch(worker->env.mesh, qinfo, flags, leeway +
                        PREFETCH_EXPIRY_ADD, rpz_passthru,
                        &repinfo->client_addr, opt_list);
                return;
        }
#endif
        /* create the prefetch in the mesh as a normal lookup without
         * client addrs waiting, which has the cache blacklisted (to bypass
         * the cache and go to the network for the data). */
        /* this (potentially) runs the mesh for the new query */
        mesh_new_prefetch(worker->env.mesh, qinfo, flags, leeway +
                PREFETCH_EXPIRY_ADD, rpz_passthru, NULL, NULL);
}

/**
 * Fill CH class answer into buffer. Keeps query.
 * @param pkt: buffer
 * @param str: string to put into text record (<255).
 *      array of strings, every string becomes a text record.
 * @param num: number of strings in array.
 * @param edns: edns reply information.
 * @param worker: worker with scratch region.
 * @param repinfo: reply information for a communication point.
 */
static void
chaos_replystr(sldns_buffer* pkt, char** str, int num, struct edns_data* edns,
        struct worker* worker, struct comm_reply* repinfo)
{
        int i;
        unsigned int rd = LDNS_RD_WIRE(sldns_buffer_begin(pkt));
        unsigned int cd = LDNS_CD_WIRE(sldns_buffer_begin(pkt));
        size_t udpsize = edns->udp_size;
        edns->edns_version = EDNS_ADVERTISED_VERSION;
        edns->udp_size = EDNS_ADVERTISED_SIZE;
        edns->ext_rcode = 0;
        edns->bits &= EDNS_DO;
        if(!inplace_cb_reply_local_call(&worker->env, NULL, NULL, NULL,
                LDNS_RCODE_NOERROR, edns, repinfo, worker->scratchpad,
                worker->env.now_tv))
                        edns->opt_list_inplace_cb_out = NULL;
        sldns_buffer_clear(pkt);
        sldns_buffer_skip(pkt, (ssize_t)sizeof(uint16_t)); /* skip id */
        sldns_buffer_write_u16(pkt, (uint16_t)(BIT_QR|BIT_RA));
        if(rd) LDNS_RD_SET(sldns_buffer_begin(pkt));
        if(cd) LDNS_CD_SET(sldns_buffer_begin(pkt));
        sldns_buffer_write_u16(pkt, 1); /* qdcount */
        sldns_buffer_write_u16(pkt, (uint16_t)num); /* ancount */
        sldns_buffer_write_u16(pkt, 0); /* nscount */
        sldns_buffer_write_u16(pkt, 0); /* arcount */
        (void)query_dname_len(pkt); /* skip qname */
        sldns_buffer_skip(pkt, (ssize_t)sizeof(uint16_t)); /* skip qtype */
        sldns_buffer_skip(pkt, (ssize_t)sizeof(uint16_t)); /* skip qclass */
        for(i=0; i<num; i++) {
                size_t len = strlen(str[i]);
                if(len>255) len=255; /* cap size of TXT record */
                if(sldns_buffer_position(pkt)+2+2+2+4+2+1+len+
                        calc_edns_field_size(edns) > udpsize) {
                        sldns_buffer_write_u16_at(pkt, 6, i); /* ANCOUNT */
                        LDNS_TC_SET(sldns_buffer_begin(pkt));
                        break;
                }
                sldns_buffer_write_u16(pkt, 0xc00c); /* compr ptr to query */
                sldns_buffer_write_u16(pkt, LDNS_RR_TYPE_TXT);
                sldns_buffer_write_u16(pkt, LDNS_RR_CLASS_CH);
                sldns_buffer_write_u32(pkt, 0); /* TTL */
                sldns_buffer_write_u16(pkt, sizeof(uint8_t) + len);
                sldns_buffer_write_u8(pkt, len);
                sldns_buffer_write(pkt, str[i], len);
        }
        sldns_buffer_flip(pkt);
        if(sldns_buffer_capacity(pkt) >=
                sldns_buffer_limit(pkt)+calc_edns_field_size(edns))
                attach_edns_record(pkt, edns);
}

/** Reply with one string */
static void
chaos_replyonestr(sldns_buffer* pkt, const char* str, struct edns_data* edns,
        struct worker* worker, struct comm_reply* repinfo)
{
        chaos_replystr(pkt, (char**)&str, 1, edns, worker, repinfo);
}

/**
 * Create CH class trustanchor answer.
 * @param pkt: buffer
 * @param edns: edns reply information.
 * @param w: worker with scratch region.
 * @param repinfo: reply information for a communication point.
 */
static void
chaos_trustanchor(sldns_buffer* pkt, struct edns_data* edns, struct worker* w,
        struct comm_reply* repinfo)
{
#define TA_RESPONSE_MAX_TXT 16 /* max number of TXT records */
#define TA_RESPONSE_MAX_TAGS 32 /* max number of tags printed per zone */
        char* str_array[TA_RESPONSE_MAX_TXT];
        uint16_t tags[TA_RESPONSE_MAX_TAGS];
        int num = 0;
        struct trust_anchor* ta;

        if(!w->env.need_to_validate) {
                /* no validator module, reply no trustanchors */
                chaos_replystr(pkt, NULL, 0, edns, w, repinfo);
                return;
        }

        /* fill the string with contents */
        lock_basic_lock(&w->env.anchors->lock);
        RBTREE_FOR(ta, struct trust_anchor*, w->env.anchors->tree) {
                char* str;
                size_t i, numtag, str_len = 255;
                if(num == TA_RESPONSE_MAX_TXT) continue;
                str = (char*)regional_alloc(w->scratchpad, str_len);
                if(!str) continue;
                lock_basic_lock(&ta->lock);
                numtag = anchor_list_keytags(ta, tags, TA_RESPONSE_MAX_TAGS);
                if(numtag == 0) {
                        /* empty, insecure point */
                        lock_basic_unlock(&ta->lock);
                        continue;
                }
                str_array[num] = str;
                num++;

                /* spool name of anchor */
                (void)sldns_wire2str_dname_buf(ta->name, ta->namelen, str, str_len);
                str_len -= strlen(str); str += strlen(str);
                /* spool tags */
                for(i=0; i<numtag; i++) {
                        snprintf(str, str_len, " %u", (unsigned)tags[i]);
                        str_len -= strlen(str); str += strlen(str);
                }
                lock_basic_unlock(&ta->lock);
        }
        lock_basic_unlock(&w->env.anchors->lock);

        chaos_replystr(pkt, str_array, num, edns, w, repinfo);
        regional_free_all(w->scratchpad);
}

/**
 * Answer CH class queries.
 * @param w: worker
 * @param qinfo: query info. Pointer into packet buffer.
 * @param edns: edns info from query.
 * @param repinfo: reply information for a communication point.
 * @param pkt: packet buffer.
 * @return: true if a reply is to be sent.
 */
static int
answer_chaos(struct worker* w, struct query_info* qinfo,
        struct edns_data* edns, struct comm_reply* repinfo, sldns_buffer* pkt)
{
        struct config_file* cfg = w->env.cfg;
        if(qinfo->qtype != LDNS_RR_TYPE_ANY && qinfo->qtype != LDNS_RR_TYPE_TXT)
                return 0;
        if(query_dname_compare(qinfo->qname,
                (uint8_t*)"\002id\006server") == 0 ||
                query_dname_compare(qinfo->qname,
                (uint8_t*)"\010hostname\004bind") == 0)
        {
                if(cfg->hide_identity)
                        return 0;
                if(cfg->identity==NULL || cfg->identity[0]==0) {
                        char buf[MAXHOSTNAMELEN+1];
                        if (gethostname(buf, MAXHOSTNAMELEN) == 0) {
                                buf[MAXHOSTNAMELEN] = 0;
                                chaos_replyonestr(pkt, buf, edns, w, repinfo);
                        } else  {
                                log_err("gethostname: %s", strerror(errno));
                                chaos_replyonestr(pkt, "no hostname", edns, w, repinfo);
                        }
                }
                else    chaos_replyonestr(pkt, cfg->identity, edns, w, repinfo);
                return 1;
        }
        if(query_dname_compare(qinfo->qname,
                (uint8_t*)"\007version\006server") == 0 ||
                query_dname_compare(qinfo->qname,
                (uint8_t*)"\007version\004bind") == 0)
        {
                if(cfg->hide_version)
                        return 0;
                if(cfg->version==NULL || cfg->version[0]==0)
                        chaos_replyonestr(pkt, PACKAGE_STRING, edns, w, repinfo);
                else    chaos_replyonestr(pkt, cfg->version, edns, w, repinfo);
                return 1;
        }
        if(query_dname_compare(qinfo->qname,
                (uint8_t*)"\013trustanchor\007unbound") == 0)
        {
                if(cfg->hide_trustanchor)
                        return 0;
                chaos_trustanchor(pkt, edns, w, repinfo);
                return 1;
        }

        return 0;
}

/**
 * Answer notify queries.  These are notifies for authoritative zones,
 * the reply is an ack that the notify has been received.  We need to check
 * access permission here.
 * @param w: worker
 * @param qinfo: query info. Pointer into packet buffer.
 * @param edns: edns info from query.
 * @param addr: client address.
 * @param addrlen: client address length.
 * @param pkt: packet buffer.
 */
static void
answer_notify(struct worker* w, struct query_info* qinfo,
        struct edns_data* edns, sldns_buffer* pkt,
        struct sockaddr_storage* addr, socklen_t addrlen)
{
        int refused = 0;
        int rcode = LDNS_RCODE_NOERROR;
        uint32_t serial = 0;
        int has_serial;
        if(!w->env.auth_zones) return;
        has_serial = auth_zone_parse_notify_serial(pkt, &serial);
        if(auth_zones_notify(w->env.auth_zones, &w->env, qinfo->qname,
                qinfo->qname_len, qinfo->qclass, addr,
                addrlen, has_serial, serial, &refused)) {
                rcode = LDNS_RCODE_NOERROR;
        } else {
                if(refused)
                        rcode = LDNS_RCODE_REFUSED;
                else    rcode = LDNS_RCODE_SERVFAIL;
        }

        if(verbosity >= VERB_DETAIL) {
                char buf[380];
                char zname[LDNS_MAX_DOMAINLEN];
                char sr[25];
                dname_str(qinfo->qname, zname);
                sr[0]=0;
                if(has_serial)
                        snprintf(sr, sizeof(sr), "serial %u ",
                                (unsigned)serial);
                if(rcode == LDNS_RCODE_REFUSED)
                        snprintf(buf, sizeof(buf),
                                "refused NOTIFY %sfor %s from", sr, zname);
                else if(rcode == LDNS_RCODE_SERVFAIL)
                        snprintf(buf, sizeof(buf),
                                "servfail for NOTIFY %sfor %s from", sr, zname);
                else    snprintf(buf, sizeof(buf),
                                "received NOTIFY %sfor %s from", sr, zname);
                log_addr(VERB_DETAIL, buf, addr, addrlen);
        }
        edns->edns_version = EDNS_ADVERTISED_VERSION;
        edns->udp_size = EDNS_ADVERTISED_SIZE;
        edns->ext_rcode = 0;
        edns->bits &= EDNS_DO;
        error_encode(pkt, rcode, qinfo,
                *(uint16_t*)(void *)sldns_buffer_begin(pkt),
                sldns_buffer_read_u16_at(pkt, 2), edns);
        LDNS_OPCODE_SET(sldns_buffer_begin(pkt), LDNS_PACKET_NOTIFY);
}

static int
deny_refuse(struct comm_point* c, enum acl_access acl,
        enum acl_access deny, enum acl_access refuse,
        struct worker* worker, struct comm_reply* repinfo,
        struct acl_addr* acladdr, int ede,
        struct check_request_result* check_result)
{
        if(acl == deny) {
                if(verbosity >= VERB_ALGO) {
                        log_acl_action("dropped", &repinfo->client_addr,
                                repinfo->client_addrlen, acl, acladdr);
                        log_buf(VERB_ALGO, "dropped", c->buffer);
                }
                comm_point_drop_reply(repinfo);
                if(worker->stats.extended)
                        worker->stats.unwanted_queries++;
                return 0;
        } else if(acl == refuse) {
                size_t opt_rr_mark;

                if(verbosity >= VERB_ALGO) {
                        log_acl_action("refused", &repinfo->client_addr,
                                repinfo->client_addrlen, acl, acladdr);
                        log_buf(VERB_ALGO, "refuse", c->buffer);
                }

                if(worker->stats.extended)
                        worker->stats.unwanted_queries++;
                worker_check_request(c->buffer, worker, check_result);
                if(check_result->value != 0) {
                        if(check_result->value != -1) {
                                query_error(c->buffer, check_result->value, 0);
                                return 1;
                        }
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
                /* worker_check_request() above guarantees that the buffer contains at
                 * least a header and that qdcount == 1
                 */
                log_assert(sldns_buffer_limit(c->buffer) >= LDNS_HEADER_SIZE
                        && LDNS_QDCOUNT(sldns_buffer_begin(c->buffer)) == 1);

                sldns_buffer_set_position(c->buffer, LDNS_HEADER_SIZE); /* skip header */

                /* check additional section is present and that we respond with EDEs */
                if(LDNS_ARCOUNT(sldns_buffer_begin(c->buffer)) != 1
                        || !ede) {
                        query_error(c->buffer, LDNS_RCODE_REFUSED, 0);
                        return 1;
                }

                if (!query_dname_len(c->buffer)) {
                        query_error(c->buffer, LDNS_RCODE_FORMERR, 0);
                        return 1;
                }
                /* space available for query type and class? */
                if (sldns_buffer_remaining(c->buffer) < 2 * sizeof(uint16_t)) {
                        query_error(c->buffer, LDNS_RCODE_FORMERR, 0);
                        return 1;
                }
                LDNS_QR_SET(sldns_buffer_begin(c->buffer));
                LDNS_RCODE_SET(sldns_buffer_begin(c->buffer),
                        LDNS_RCODE_REFUSED);

                sldns_buffer_skip(c->buffer, (ssize_t)sizeof(uint16_t)); /* skip qtype */

                sldns_buffer_skip(c->buffer, (ssize_t)sizeof(uint16_t)); /* skip qclass */

                /* The OPT RR to be returned should come directly after
                 * the query, so mark this spot.
                 */
                opt_rr_mark = sldns_buffer_position(c->buffer);

                /* Skip through the RR records */
                if(LDNS_ANCOUNT(sldns_buffer_begin(c->buffer)) != 0 ||
                        LDNS_NSCOUNT(sldns_buffer_begin(c->buffer)) != 0) {
                        if(!skip_pkt_rrs(c->buffer,
                                ((int)LDNS_ANCOUNT(sldns_buffer_begin(c->buffer)))+
                                ((int)LDNS_NSCOUNT(sldns_buffer_begin(c->buffer))))) {
                                query_error(c->buffer, LDNS_RCODE_FORMERR,
                                        opt_rr_mark - LDNS_HEADER_SIZE
                                        - 2 /* qtype */ - 2 /* qclass */);
                                return 1;
                        }
                }
                /* Do we have a valid OPT RR here? If not return REFUSED (could be a valid TSIG or something so no FORMERR) */
                /* domain name must be the root of length 1. */
                if(sldns_buffer_remaining(c->buffer) < 1 || *sldns_buffer_current(c->buffer) != 0) {
                        query_error(c->buffer, LDNS_RCODE_REFUSED,
                                opt_rr_mark - LDNS_HEADER_SIZE
                                - 2 /* qtype */ - 2 /* qclass */);
                        return 1;
                } else {
                        sldns_buffer_skip(c->buffer, 1); /* skip root label */
                }
                if(sldns_buffer_remaining(c->buffer) < 2 ||
                        sldns_buffer_read_u16(c->buffer) != LDNS_RR_TYPE_OPT) {
                        query_error(c->buffer, LDNS_RCODE_REFUSED,
                                opt_rr_mark - LDNS_HEADER_SIZE
                                - 2 /* qtype */ - 2 /* qclass */);
                        return 1;
                }
                /* Write OPT RR directly after the query,
                 * so without the (possibly skipped) Answer and NS RRs
                 */
                LDNS_ANCOUNT_SET(sldns_buffer_begin(c->buffer), 0);
                LDNS_NSCOUNT_SET(sldns_buffer_begin(c->buffer), 0);
                sldns_buffer_clear(c->buffer); /* reset write limit */
                sldns_buffer_set_position(c->buffer, opt_rr_mark);

                /* Check if OPT record can be written
                 * 17 == root label (1) + RR type (2) + UDP Size (2)
                 *     + Fields (4) + rdata len (2) + EDE Option code (2)
                 *     + EDE Option length (2) + EDE info-code (2)
                 */
                if (sldns_buffer_available(c->buffer, 17) == 0) {
                        LDNS_ARCOUNT_SET(sldns_buffer_begin(c->buffer), 0);
                        sldns_buffer_flip(c->buffer);
                        return 1;
                }

                LDNS_ARCOUNT_SET(sldns_buffer_begin(c->buffer), 1);

                /* root label */
                sldns_buffer_write_u8(c->buffer, 0);
                sldns_buffer_write_u16(c->buffer, LDNS_RR_TYPE_OPT);
                sldns_buffer_write_u16(c->buffer, EDNS_ADVERTISED_SIZE);

                /* write OPT Record TTL Field */
                sldns_buffer_write_u32(c->buffer, 0);

                /* write rdata len: EDE option + length + info-code */
                sldns_buffer_write_u16(c->buffer, 6);

                /* write OPTIONS; add EDE option code */
                sldns_buffer_write_u16(c->buffer, LDNS_EDNS_EDE);

                /* write single EDE option length (for just 1 info-code) */
                sldns_buffer_write_u16(c->buffer, 2);

                /* write single EDE info-code */
                sldns_buffer_write_u16(c->buffer, LDNS_EDE_PROHIBITED);

                sldns_buffer_flip(c->buffer);

                verbose(VERB_ALGO, "attached EDE code: %d", LDNS_EDE_PROHIBITED);

                return 1;

        }

        return -1;
}

static int
deny_refuse_all(struct comm_point* c, enum acl_access* acl,
        struct worker* worker, struct comm_reply* repinfo,
        struct acl_addr** acladdr, int ede, int check_proxy,
        struct check_request_result* check_result)
{
        if(check_proxy) {
                *acladdr = acl_addr_lookup(worker->daemon->acl,
                        &repinfo->remote_addr, repinfo->remote_addrlen);
        } else {
                *acladdr = acl_addr_lookup(worker->daemon->acl,
                        &repinfo->client_addr, repinfo->client_addrlen);
        }
        /* If there is no ACL based on client IP use the interface ACL. */
        if(!(*acladdr) && c->socket) {
                *acladdr = c->socket->acl;
        }
        *acl = acl_get_control(*acladdr);
        return deny_refuse(c, *acl, acl_deny, acl_refuse, worker, repinfo,
                *acladdr, ede, check_result);
}

static int
deny_refuse_non_local(struct comm_point* c, enum acl_access acl,
        struct worker* worker, struct comm_reply* repinfo,
        struct acl_addr* acladdr, int ede,
        struct check_request_result* check_result)
{
        return deny_refuse(c, acl, acl_deny_non_local, acl_refuse_non_local,
                worker, repinfo, acladdr, ede, check_result);
}

/* Check if the query is blocked by source IP rate limiting.
 * Returns 1 if it passes the check, 0 otherwise. */
static int
check_ip_ratelimit(struct worker* worker, struct sockaddr_storage* addr,
        socklen_t addrlen, int has_cookie, sldns_buffer* pkt)
{
        if(!infra_ip_ratelimit_inc(worker->env.infra_cache, addr, addrlen,
                        *worker->env.now, has_cookie,
                        worker->env.cfg->ip_ratelimit_backoff, pkt)) {
                /* See if we can pass through with slip factor */
                if(!has_cookie && worker->env.cfg->ip_ratelimit_factor != 0 &&
                        ub_random_max(worker->env.rnd,
                        worker->env.cfg->ip_ratelimit_factor) == 0) {
                        char addrbuf[128];
                        addr_to_str(addr, addrlen, addrbuf, sizeof(addrbuf));
                        verbose(VERB_QUERY, "ip_ratelimit allowed through for "
                                "ip address %s because of slip in "
                                "ip_ratelimit_factor", addrbuf);
                        return 1;
                }
                return 0;
        }
        return 1;
}

/*
 * This is the callback function when a request arrives. It is passed
 * the packet and user argument. Return true to send a reply.
 * This is of type comm_point_callback_type. The struct comm_point contains
 * more comments on the comm_point.callback member about the function.
 * @param c: the comm_point where the request arrives on.
 * @param arg: the user argument for the callback, the worker.
 * @param error: This can be NETEVENT_NOERROR, NETEVENT_TIMEOUT,
 *      NETEVENT_CLOSED or other comm point callback error values.
 * @param repinfo: The reply info, use it to send a reply. If the reply
 *      is immediate, return 1. If the reply is later on return 0 and save
 *      the repinfo, to call comm_point_send_reply on.
 * @return 1 to sent a reply straight away, for like cache response so that
 *      no allocation needs to be done. And only internal preallocated buffers
 *      are used. Return 0 and save the repinfo to reply later, for responses
 *      that need to be looked up. Return 0 and call comm_point_drop_reply on
 *      the repinfo to drop the response.
 */
int
worker_handle_request(struct comm_point* c, void* arg, int error,
        struct comm_reply* repinfo)
{
        struct worker* worker = (struct worker*)arg;
        int ret;
        hashvalue_type h;
        struct lruhash_entry* e;
        struct query_info qinfo;
        struct edns_data edns;
        struct edns_option* original_edns_list = NULL;
        enum acl_access acl;
        struct acl_addr* acladdr;
        int pre_edns_ip_ratelimit = 1;
        int rc = 0;
        int need_drop = 0;
        int is_expired_answer = 0;
        int is_secure_answer = 0;
        int rpz_passthru = 0;
        long long wait_queue_time = 0;
        /* We might have to chase a CNAME chain internally, in which case
         * we'll have up to two replies and combine them to build a complete
         * answer.  These variables control this case. */
        struct ub_packed_rrset_key* alias_rrset = NULL;
        struct reply_info* partial_rep = NULL;
        struct query_info* lookup_qinfo = &qinfo;
        struct query_info qinfo_tmp; /* placeholder for lookup_qinfo */
        struct respip_client_info* cinfo = NULL, cinfo_tmp;
        struct timeval wait_time;
        struct check_request_result check_result = {0,0};
        memset(&qinfo, 0, sizeof(qinfo));

        if((error != NETEVENT_NOERROR && error != NETEVENT_DONE)|| !repinfo) {
                /* some bad tcp query DNS formats give these error calls */
                verbose(VERB_ALGO, "handle request called with err=%d", error);
                return 0;
        }

        if (worker->env.cfg->sock_queue_timeout && timeval_isset(&c->recv_tv)) {
                timeval_subtract(&wait_time, worker->env.now_tv, &c->recv_tv);
                wait_queue_time = wait_time.tv_sec * 1000000 +  wait_time.tv_usec;
                if (worker->stats.max_query_time_us < wait_queue_time)
                        worker->stats.max_query_time_us = wait_queue_time;
                if(wait_queue_time >
                        (long long)(worker->env.cfg->sock_queue_timeout * 1000000)) {
                        /* count and drop queries that were sitting in the socket queue too long */
                        worker->stats.num_queries_timed_out++;
                        return 0;
                }
        }

#ifdef USE_DNSCRYPT
        repinfo->max_udp_size = worker->daemon->cfg->max_udp_size;
        if(!dnsc_handle_curved_request(worker->daemon->dnscenv, repinfo)) {
                worker->stats.num_query_dnscrypt_crypted_malformed++;
                return 0;
        }
        if(c->dnscrypt && !repinfo->is_dnscrypted) {
                char buf[LDNS_MAX_DOMAINLEN];
                /* Check if this is unencrypted and asking for certs */
                worker_check_request(c->buffer, worker, &check_result);
                if(check_result.value != 0) {
                        verbose(VERB_ALGO,
                                "dnscrypt: worker check request: bad query.");
                        log_addr(VERB_CLIENT,"from",&repinfo->client_addr,
                                repinfo->client_addrlen);
                        if(check_result.value != -1) {
                                query_error(c->buffer, check_result.value, 0);
                                return 1;
                        }
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
                if(!query_info_parse(&qinfo, c->buffer)) {
                        verbose(VERB_ALGO,
                                "dnscrypt: worker parse request: formerror.");
                        log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
                                repinfo->client_addrlen);
                        if(worker_err_ratelimit(worker, LDNS_RCODE_FORMERR) == -1) {
                                comm_point_drop_reply(repinfo);
                                return 0;
                        }
                        query_error(c->buffer, LDNS_RCODE_FORMERR, 0);
                        sldns_buffer_copy(c->dnscrypt_buffer, c->buffer);
                        return 1;
                }
                dname_str(qinfo.qname, buf);
                if(!(qinfo.qtype == LDNS_RR_TYPE_TXT &&
                        strcasecmp(buf,
                        worker->daemon->dnscenv->provider_name) == 0)) {
                        verbose(VERB_ALGO,
                                "dnscrypt: not TXT \"%s\". Received: %s \"%s\"",
                                worker->daemon->dnscenv->provider_name,
                                sldns_rr_descript(qinfo.qtype)->_name,
                                buf);
                        if(worker_err_ratelimit(worker, LDNS_RCODE_SERVFAIL) == -1) {
                                comm_point_drop_reply(repinfo);
                                return 0;
                        }
                        query_error(c->buffer, LDNS_RCODE_SERVFAIL,
                                qinfo.qname_len);
                        worker->stats.num_query_dnscrypt_cleartext++;
                        sldns_buffer_copy(c->dnscrypt_buffer, c->buffer);
                        return 1;
                }
                worker->stats.num_query_dnscrypt_cert++;
                sldns_buffer_rewind(c->buffer);
        } else if(c->dnscrypt && repinfo->is_dnscrypted) {
                worker->stats.num_query_dnscrypt_crypted++;
        }
#endif
#ifdef USE_DNSTAP
        /*
         * sending src (client)/dst (local service) addresses over DNSTAP from incoming request handler
         */
        if(worker->dtenv.log_client_query_messages) {
                log_addr(VERB_ALGO, "request from client", &repinfo->client_addr, repinfo->client_addrlen);
                log_addr(VERB_ALGO, "to local addr", (void*)repinfo->c->socket->addr, repinfo->c->socket->addrlen);
                dt_msg_send_client_query(&worker->dtenv, &repinfo->client_addr, (void*)repinfo->c->socket->addr, c->type, c->ssl, c->buffer,
                ((worker->env.cfg->sock_queue_timeout && timeval_isset(&c->recv_tv))?&c->recv_tv:NULL));
        }
#endif
        /* Check deny/refuse ACLs */
        if(repinfo->is_proxied) {
                if((ret=deny_refuse_all(c, &acl, worker, repinfo, &acladdr,
                        worker->env.cfg->ede, 1, &check_result)) != -1) {
                        if(ret == 1)
                                goto send_reply;
                        return ret;
                }
        }
        if((ret=deny_refuse_all(c, &acl, worker, repinfo, &acladdr,
                worker->env.cfg->ede, 0, &check_result)) != -1) {
                if(ret == 1)
                        goto send_reply;
                return ret;
        }

        worker_check_request(c->buffer, worker, &check_result);
        if(check_result.value != 0) {
                verbose(VERB_ALGO, "worker check request: bad query.");
                log_addr(VERB_CLIENT,"from",&repinfo->client_addr, repinfo->client_addrlen);
                if(check_result.value != -1) {
                        query_error(c->buffer, check_result.value, 0);
                        return 1;
                }
                comm_point_drop_reply(repinfo);
                return 0;
        }

        worker->stats.num_queries++;
        pre_edns_ip_ratelimit = !worker->env.cfg->do_answer_cookie
                || sldns_buffer_limit(c->buffer) < LDNS_HEADER_SIZE
                || LDNS_ARCOUNT(sldns_buffer_begin(c->buffer)) == 0;

        /* If the IP rate limiting check needs extra EDNS information (e.g.,
         * DNS Cookies) postpone the check until after EDNS is parsed. */
        if(pre_edns_ip_ratelimit) {
                /* NOTE: we always check the repinfo->client_address.
                 *       IP ratelimiting is implicitly disabled for proxies. */
                if(!check_ip_ratelimit(worker, &repinfo->client_addr,
                        repinfo->client_addrlen, 0, c->buffer)) {
                        worker->stats.num_queries_ip_ratelimited++;
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
        }

        if(!query_info_parse(&qinfo, c->buffer)) {
                verbose(VERB_ALGO, "worker parse request: formerror.");
                log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
                        repinfo->client_addrlen);
                memset(&qinfo, 0, sizeof(qinfo)); /* zero qinfo.qname */
                if(worker_err_ratelimit(worker, LDNS_RCODE_FORMERR) == -1) {
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
                query_error(c->buffer, LDNS_RCODE_FORMERR, 0);
                goto send_reply;
        }
        if(worker->env.cfg->log_queries) {
                char ip[128];
                addr_to_str(&repinfo->client_addr, repinfo->client_addrlen, ip, sizeof(ip));
                log_query_in(ip, qinfo.qname, qinfo.qtype, qinfo.qclass);
        }
        if(qinfo.qtype == LDNS_RR_TYPE_AXFR ||
                qinfo.qtype == LDNS_RR_TYPE_IXFR) {
                verbose(VERB_ALGO, "worker request: refused zone transfer.");
                log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
                        repinfo->client_addrlen);
                if(worker_err_ratelimit(worker, LDNS_RCODE_REFUSED) == -1) {
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
                query_error(c->buffer, LDNS_RCODE_REFUSED, qinfo.qname_len);
                if(worker->stats.extended) {
                        worker->stats.qtype[qinfo.qtype]++;
                }
                goto send_reply;
        }
        if(qinfo.qtype == LDNS_RR_TYPE_OPT ||
                qinfo.qtype == LDNS_RR_TYPE_TSIG ||
                qinfo.qtype == LDNS_RR_TYPE_TKEY ||
                qinfo.qtype == LDNS_RR_TYPE_MAILA ||
                qinfo.qtype == LDNS_RR_TYPE_MAILB ||
                (qinfo.qtype >= 128 && qinfo.qtype <= 248)) {
                verbose(VERB_ALGO, "worker request: formerror for meta-type.");
                log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
                        repinfo->client_addrlen);
                if(worker_err_ratelimit(worker, LDNS_RCODE_FORMERR) == -1) {
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
                query_error(c->buffer, LDNS_RCODE_FORMERR, qinfo.qname_len);
                if(worker->stats.extended) {
                        worker->stats.qtype[qinfo.qtype]++;
                }
                goto send_reply;
        }
        if((ret=parse_edns_from_query_pkt(
                        c->buffer, &edns, worker->env.cfg, c, repinfo,
                        *worker->env.now, worker->scratchpad,
                        worker->daemon->cookie_secrets)) != 0) {
                struct edns_data reply_edns;
                verbose(VERB_ALGO, "worker parse edns: formerror.");
                log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
                        repinfo->client_addrlen);
                if(worker_err_ratelimit(worker, ret) == -1) {
                        comm_point_drop_reply(repinfo);
                        regional_free_all(worker->scratchpad);
                        return 0;
                }
                memset(&reply_edns, 0, sizeof(reply_edns));
                reply_edns.edns_present = 1;
                error_encode(c->buffer, ret, &qinfo,
                        *(uint16_t*)(void *)sldns_buffer_begin(c->buffer),
                        sldns_buffer_read_u16_at(c->buffer, 2), &reply_edns);
                regional_free_all(worker->scratchpad);
                goto send_reply;
        }
        if(edns.edns_present) {
                if(edns.edns_version != 0) {
                        edns.opt_list_in = NULL;
                        edns.opt_list_out = NULL;
                        edns.opt_list_inplace_cb_out = NULL;
                        verbose(VERB_ALGO, "query with bad edns version.");
                        log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
                                repinfo->client_addrlen);
                        if(worker_err_ratelimit(worker, EDNS_RCODE_BADVERS) == -1) {
                                comm_point_drop_reply(repinfo);
                                regional_free_all(worker->scratchpad);
                                return 0;
                        }
                        extended_error_encode(c->buffer, EDNS_RCODE_BADVERS, &qinfo,
                                *(uint16_t*)(void *)sldns_buffer_begin(c->buffer),
                                sldns_buffer_read_u16_at(c->buffer, 2), 0, &edns);
                        regional_free_all(worker->scratchpad);
                        goto send_reply;
                }
                if(edns.udp_size < NORMAL_UDP_SIZE &&
                   worker->daemon->cfg->harden_short_bufsize) {
                        verbose(VERB_QUERY, "worker request: EDNS bufsize %d ignored",
                                (int)edns.udp_size);
                        log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
                                repinfo->client_addrlen);
                        edns.udp_size = NORMAL_UDP_SIZE;
                }
        }

        /* Get stats for cookies */
        server_stats_downstream_cookie(&worker->stats, &edns);

        /* If the IP rate limiting check was postponed, check now. */
        if(!pre_edns_ip_ratelimit) {
                /* NOTE: we always check the repinfo->client_address.
                 *       IP ratelimiting is implicitly disabled for proxies. */
                if(!check_ip_ratelimit(worker, &repinfo->client_addr,
                        repinfo->client_addrlen, edns.cookie_valid,
                        c->buffer)) {
                        worker->stats.num_queries_ip_ratelimited++;
                        regional_free_all(worker->scratchpad);
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
        }

        /* "if, else if" sequence below deals with downstream DNS Cookies */
        if(acl != acl_allow_cookie)
                ; /* pass; No cookie downstream processing whatsoever */

        else if(edns.cookie_valid)
                ; /* pass; Valid cookie is good! */

        else if(c->type != comm_udp)
                ; /* pass; Stateful transport */

        else if(edns.cookie_present) {
                /* Cookie present, but not valid: Cookie was bad! */
                if(worker_err_ratelimit(worker, LDNS_EXT_RCODE_BADCOOKIE) == -1) {
                        comm_point_drop_reply(repinfo);
                        regional_free_all(worker->scratchpad);
                        return 0;
                }
                extended_error_encode(c->buffer,
                        LDNS_EXT_RCODE_BADCOOKIE, &qinfo,
                        *(uint16_t*)(void *)
                        sldns_buffer_begin(c->buffer),
                        sldns_buffer_read_u16_at(c->buffer, 2),
                        0, &edns);
                regional_free_all(worker->scratchpad);
                goto send_reply;
        } else {
                /* Cookie required, but no cookie present on UDP */
                verbose(VERB_ALGO, "worker request: "
                        "need cookie or stateful transport");
                log_addr(VERB_ALGO, "from",&repinfo->remote_addr
                                          , repinfo->remote_addrlen);
                if(worker_err_ratelimit(worker, LDNS_RCODE_REFUSED) == -1) {
                        comm_point_drop_reply(repinfo);
                        regional_free_all(worker->scratchpad);
                        return 0;
                }
                EDNS_OPT_LIST_APPEND_EDE(&edns.opt_list_out,
                        worker->scratchpad, LDNS_EDE_OTHER,
                        "DNS Cookie needed for UDP replies");
                error_encode(c->buffer,
                        (LDNS_RCODE_REFUSED|BIT_TC), &qinfo,
                        *(uint16_t*)(void *)
                        sldns_buffer_begin(c->buffer),
                        sldns_buffer_read_u16_at(c->buffer, 2),
                        &edns);
                regional_free_all(worker->scratchpad);
                goto send_reply;
        }

        if(edns.udp_size > worker->daemon->cfg->max_udp_size &&
                c->type == comm_udp) {
                verbose(VERB_QUERY,
                        "worker request: max UDP reply size modified"
                        " (%d to max-udp-size)", (int)edns.udp_size);
                log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
                        repinfo->client_addrlen);
                edns.udp_size = worker->daemon->cfg->max_udp_size;
        }
        if(edns.udp_size < LDNS_HEADER_SIZE) {
                verbose(VERB_ALGO, "worker request: edns is too small.");
                log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
                        repinfo->client_addrlen);
                if(worker_err_ratelimit(worker, LDNS_RCODE_SERVFAIL) == -1) {
                        comm_point_drop_reply(repinfo);
                        regional_free_all(worker->scratchpad);
                        return 0;
                }
                /* A small error without qname, and TC flag on. */
                query_error(c->buffer, LDNS_RCODE_SERVFAIL, 0);
                LDNS_TC_SET(sldns_buffer_begin(c->buffer));
                regional_free_all(worker->scratchpad);
                goto send_reply;
        }
        if(worker->stats.extended)
                server_stats_insquery(&worker->stats, c, qinfo.qtype,
                        qinfo.qclass, &edns, repinfo);
        if(c->type != comm_udp)
#ifdef USE_DNSCRYPT
                edns.udp_size = (c->dnscrypt && repinfo->is_dnscrypted)
                        ? sldns_buffer_capacity(c->buffer) - DNSCRYPT_REPLY_HEADER_SIZE
                        : 65535;
#else
                edns.udp_size = 65535; /* max size for TCP replies */
#endif
        if(qinfo.qclass == LDNS_RR_CLASS_CH && answer_chaos(worker, &qinfo,
                &edns, repinfo, c->buffer)) {
                regional_free_all(worker->scratchpad);
                goto send_reply;
        }
        if(LDNS_OPCODE_WIRE(sldns_buffer_begin(c->buffer)) ==
                LDNS_PACKET_NOTIFY) {
                answer_notify(worker, &qinfo, &edns, c->buffer,
                        &repinfo->client_addr, repinfo->client_addrlen);
                regional_free_all(worker->scratchpad);
                goto send_reply;
        }
        if(local_zones_answer(worker->daemon->local_zones, &worker->env, &qinfo,
                &edns, c->buffer, worker->scratchpad, repinfo, acladdr->taglist,
                acladdr->taglen, acladdr->tag_actions,
                acladdr->tag_actions_size, acladdr->tag_datas,
                acladdr->tag_datas_size, worker->daemon->cfg->tagname,
                worker->daemon->cfg->num_tags, acladdr->view)) {
                regional_free_all(worker->scratchpad);
                if(sldns_buffer_limit(c->buffer) == 0) {
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
                goto send_reply;
        }
        if(worker->env.auth_zones &&
                rpz_callback_from_worker_request(worker->env.auth_zones,
                &worker->env, &qinfo, &edns, c->buffer, worker->scratchpad,
                repinfo, acladdr->taglist, acladdr->taglen, &worker->stats,
                &rpz_passthru)) {
                regional_free_all(worker->scratchpad);
                if(sldns_buffer_limit(c->buffer) == 0) {
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
                goto send_reply;
        }
        if(worker->env.auth_zones &&
                auth_zones_downstream_answer(worker->env.auth_zones,
                &worker->env, &qinfo, &edns, repinfo, c->buffer,
                worker->scratchpad)) {
                regional_free_all(worker->scratchpad);
                if(sldns_buffer_limit(c->buffer) == 0) {
                        comm_point_drop_reply(repinfo);
                        return 0;
                }
                /* set RA for everyone that can have recursion (based on
                 * access control list) */
                if(LDNS_RD_WIRE(sldns_buffer_begin(c->buffer)) &&
                   acl != acl_deny_non_local && acl != acl_refuse_non_local)
                        LDNS_RA_SET(sldns_buffer_begin(c->buffer));
                goto send_reply;
        }

        /* We've looked in our local zones. If the answer isn't there, we
         * might need to bail out based on ACLs now. */
        if((ret=deny_refuse_non_local(c, acl, worker, repinfo, acladdr,
                worker->env.cfg->ede, &check_result)) != -1)
        {
                regional_free_all(worker->scratchpad);
                if(ret == 1)
                        goto send_reply;
                return ret;
        }

        /* If this request does not have the recursion bit set, verify
         * ACLs allow the recursion bit to be treated as set. */
        if(!(LDNS_RD_WIRE(sldns_buffer_begin(c->buffer))) &&
                acl == acl_allow_setrd ) {
                LDNS_RD_SET(sldns_buffer_begin(c->buffer));
        }

        /* If this request does not have the recursion bit set, verify
         * ACLs allow the snooping. */
        if(!(LDNS_RD_WIRE(sldns_buffer_begin(c->buffer))) &&
                acl != acl_allow_snoop ) {
                log_addr(VERB_ALGO, "refused nonrec (cache snoop) query from",
                        &repinfo->client_addr, repinfo->client_addrlen);
                /* This ratelimited error query is accounted in the stats,
                 * as an incoming query. */
                if(worker_err_ratelimit(worker, LDNS_RCODE_REFUSED) == -1) {
                        comm_point_drop_reply(repinfo);
                        regional_free_all(worker->scratchpad);
                        return 0;
                }
                if(worker->env.cfg->ede) {
                        EDNS_OPT_LIST_APPEND_EDE(&edns.opt_list_out,
                                worker->scratchpad, LDNS_EDE_NOT_AUTHORITATIVE, "");
                }
                error_encode(c->buffer, LDNS_RCODE_REFUSED, &qinfo,
                        *(uint16_t*)(void *)sldns_buffer_begin(c->buffer),
                        sldns_buffer_read_u16_at(c->buffer, 2), &edns);
                regional_free_all(worker->scratchpad);
                goto send_reply;
        }

        /* If we've found a local alias, replace the qname with the alias
         * target before resolving it. */
        if(qinfo.local_alias) {
                if(!local_alias_shallow_copy_qname(qinfo.local_alias, &qinfo.qname,
                        &qinfo.qname_len)) {
                        regional_free_all(worker->scratchpad);
                        return 0; /* drop it */
                }
        }

        /* If we may apply IP-based actions to the answer, build the client
         * information.  As this can be expensive, skip it if there is
         * absolutely no possibility of it. */
        if((worker->daemon->use_response_ip || worker->daemon->use_rpz) &&
                (qinfo.qtype == LDNS_RR_TYPE_A ||
                qinfo.qtype == LDNS_RR_TYPE_AAAA ||
                qinfo.qtype == LDNS_RR_TYPE_ANY)) {
                cinfo_tmp.taglist = acladdr->taglist;
                cinfo_tmp.taglen = acladdr->taglen;
                cinfo_tmp.tag_actions = acladdr->tag_actions;
                cinfo_tmp.tag_actions_size = acladdr->tag_actions_size;
                cinfo_tmp.tag_datas = acladdr->tag_datas;
                cinfo_tmp.tag_datas_size = acladdr->tag_datas_size;
                cinfo_tmp.view = acladdr->view;
                cinfo_tmp.view_name = NULL;
                cinfo = &cinfo_tmp;
        }

        /* Keep the original edns list around. The pointer could change if there is
         * a cached answer (through the inplace callback function there).
         * No need to actually copy the contents as they shouldn't change.
         * Used while prefetching and subnet is enabled. */
        original_edns_list = edns.opt_list_in;
lookup_cache:
        /* Lookup the cache.  In case we chase an intermediate CNAME chain
         * this is a two-pass operation, and lookup_qinfo is different for
         * each pass.  We should still pass the original qinfo to
         * answer_from_cache(), however, since it's used to build the reply. */
        if(!edns_bypass_cache_stage(edns.opt_list_in, &worker->env)) {
                is_expired_answer = 0;
                is_secure_answer = 0;
                h = query_info_hash(lookup_qinfo, sldns_buffer_read_u16_at(c->buffer, 2));
                if((e=slabhash_lookup(worker->env.msg_cache, h, lookup_qinfo, 0))) {
                        struct reply_info* rep = (struct reply_info*)e->data;
                        /* answer from cache - we have acquired a readlock on it */
                        if(answer_from_cache(worker, &qinfo, cinfo, &need_drop,
                                &is_expired_answer, &is_secure_answer,
                                &alias_rrset, &partial_rep, rep,
                                *(uint16_t*)(void *)sldns_buffer_begin(c->buffer),
                                sldns_buffer_read_u16_at(c->buffer, 2), repinfo,
                                &edns)) {
                                /* prefetch it if the prefetch TTL expired.
                                 * Note that if there is more than one pass
                                 * its qname must be that used for cache
                                 * lookup. */
                                if((worker->env.cfg->prefetch &&
                                        rep->prefetch_ttl <= *worker->env.now) ||
                                        (worker->env.cfg->serve_expired &&
                                        TTL_IS_EXPIRED(rep->ttl, *worker->env.now) &&
                                        !(*worker->env.now < rep->serve_expired_norec_ttl))) {
                                        time_t leeway =
                                                TTL_IS_EXPIRED(rep->ttl, *worker->env.now)
                                                ? 0 : rep->ttl - *worker->env.now;
                                        lock_rw_unlock(&e->lock);

                                        reply_and_prefetch(worker, lookup_qinfo,
                                                sldns_buffer_read_u16_at(c->buffer, 2),
                                                repinfo, leeway,
                                                (partial_rep || need_drop),
                                                rpz_passthru,
                                                original_edns_list);
                                        if(!partial_rep) {
                                                rc = 0;
                                                regional_free_all(worker->scratchpad);
                                                goto send_reply_rc;
                                        }
                                } else if(!partial_rep) {
                                        lock_rw_unlock(&e->lock);
                                        regional_free_all(worker->scratchpad);
                                        goto send_reply;
                                } else {
                                        /* Note that we've already released the
                                         * lock if we're here after prefetch. */
                                        lock_rw_unlock(&e->lock);
                                }
                                /* We've found a partial reply ending with an
                                 * alias.  Replace the lookup qinfo for the
                                 * alias target and lookup the cache again to
                                 * (possibly) complete the reply.  As we're
                                 * passing the "base" reply, there will be no
                                 * more alias chasing. */
                                memset(&qinfo_tmp, 0, sizeof(qinfo_tmp));
                                get_cname_target(alias_rrset, &qinfo_tmp.qname,
                                        &qinfo_tmp.qname_len);
                                if(!qinfo_tmp.qname) {
                                        log_err("unexpected: invalid answer alias");
                                        regional_free_all(worker->scratchpad);
                                        return 0; /* drop query */
                                }
                                qinfo_tmp.qtype = qinfo.qtype;
                                qinfo_tmp.qclass = qinfo.qclass;
                                lookup_qinfo = &qinfo_tmp;
                                goto lookup_cache;
                        }
                        verbose(VERB_ALGO, "answer from the cache failed");
                        lock_rw_unlock(&e->lock);
                }

                if(!LDNS_RD_WIRE(sldns_buffer_begin(c->buffer))) {
                        if(answer_norec_from_cache(worker, &qinfo,
                                *(uint16_t*)(void *)sldns_buffer_begin(c->buffer),
                                sldns_buffer_read_u16_at(c->buffer, 2), repinfo,
                                &edns)) {
                                regional_free_all(worker->scratchpad);
                                goto send_reply;
                        }
                        verbose(VERB_ALGO, "answer norec from cache -- "
                                "need to validate or not primed");
                }
        }
        sldns_buffer_rewind(c->buffer);
        server_stats_querymiss(&worker->stats, worker);

        if(verbosity >= VERB_CLIENT) {
                if(c->type == comm_udp)
                        log_addr(VERB_CLIENT, "udp request from",
                                &repinfo->client_addr, repinfo->client_addrlen);
                else    log_addr(VERB_CLIENT, "tcp request from",
                                &repinfo->client_addr, repinfo->client_addrlen);
        }

        /* grab a work request structure for this new request */
        mesh_new_client(worker->env.mesh, &qinfo, cinfo,
                sldns_buffer_read_u16_at(c->buffer, 2),
                &edns, repinfo, *(uint16_t*)(void *)sldns_buffer_begin(c->buffer),
                rpz_passthru);
        regional_free_all(worker->scratchpad);
        worker_mem_report(worker, NULL);
        return 0;

send_reply:
        rc = 1;
send_reply_rc:
        if(need_drop) {
                comm_point_drop_reply(repinfo);
                return 0;
        }
        if(is_expired_answer) {
                worker->stats.ans_expired++;
        }
        server_stats_insrcode(&worker->stats, c->buffer);
        if(worker->stats.extended) {
                if(is_secure_answer) worker->stats.ans_secure++;
        }
#ifdef USE_DNSTAP
        /*
         * sending src (client)/dst (local service) addresses over DNSTAP from send_reply code label (when we serviced local zone for ex.)
         */
        if(worker->dtenv.log_client_response_messages && rc !=0) {
                log_addr(VERB_ALGO, "from local addr", (void*)repinfo->c->socket->addr, repinfo->c->socket->addrlen);
                log_addr(VERB_ALGO, "response to client", &repinfo->client_addr, repinfo->client_addrlen);
                dt_msg_send_client_response(&worker->dtenv, &repinfo->client_addr, (void*)repinfo->c->socket->addr, c->type, c->ssl, c->buffer);
        }
#endif
        if(worker->env.cfg->log_replies)
        {
                struct timeval tv;
                memset(&tv, 0, sizeof(tv));
                if(qinfo.local_alias && qinfo.local_alias->rrset &&
                        qinfo.local_alias->rrset->rk.dname) {
                        /* log original qname, before the local alias was
                         * used to resolve that CNAME to something else */
                        qinfo.qname = qinfo.local_alias->rrset->rk.dname;
                        log_reply_info(NO_VERBOSE, &qinfo,
                                &repinfo->client_addr, repinfo->client_addrlen,
                                tv, 1, c->buffer,
                                (worker->env.cfg->log_destaddr?(void*)repinfo->c->socket->addr:NULL),
                                c->type, c->ssl);
                } else {
                        log_reply_info(NO_VERBOSE, &qinfo,
                                &repinfo->client_addr, repinfo->client_addrlen,
                                tv, 1, c->buffer,
                                (worker->env.cfg->log_destaddr?(void*)repinfo->c->socket->addr:NULL),
                                c->type, c->ssl);
                }
        }
#ifdef USE_DNSCRYPT
        if(!dnsc_handle_uncurved_request(repinfo, c->buffer)) {
                return 0;
        }
#endif
        return rc;
}

void
worker_sighandler(int sig, void* arg)
{
        /* note that log, print, syscalls here give race conditions.
         * And cause hangups if the log-lock is held by the application. */
        struct worker* worker = (struct worker*)arg;
        switch(sig) {
#ifdef SIGHUP
                case SIGHUP:
                        comm_base_exit(worker->base);
                        break;
#endif
#ifdef SIGBREAK
                case SIGBREAK:
#endif
                case SIGINT:
                        worker->need_to_exit = 1;
                        comm_base_exit(worker->base);
                        break;
#ifdef SIGQUIT
                case SIGQUIT:
                        worker->need_to_exit = 1;
                        comm_base_exit(worker->base);
                        break;
#endif
                case SIGTERM:
                        worker->need_to_exit = 1;
                        comm_base_exit(worker->base);
                        break;
                default:
                        /* unknown signal, ignored */
                        break;
        }
}

/** restart statistics timer for worker, if enabled */
static void
worker_restart_timer(struct worker* worker)
{
        if(worker->env.cfg->stat_interval > 0) {
                struct timeval tv;
                if(worker->daemon->stat_time_specific) {
                        struct timeval dest, now;
                        int interval = worker->env.cfg->stat_interval;
                        int offset = worker->daemon->stat_time_offset;
                        int nows, spec;
                        if(gettimeofday(&now, NULL) < 0)
                                log_err("gettimeofday: %s", strerror(errno));
#ifndef S_SPLINT_S
                        nows = (int)now.tv_sec;
                        /* The next time is on the timer interval, at the
                         * specific offset, time value % interval = offset. */
                        /* It relies on the integer division below to drop the
                         * remainder in order to calculate the expected
                         * result. */
                        spec = ((nows-offset)/interval+1)*interval+offset;
                        /* This is instead of an assertion, and should not
                         * be needed. So assert(spec > nows), tv is going to
                         * be positive. */
                        if(spec<=nows) spec += interval;
                        dest.tv_sec = spec;
                        dest.tv_usec = 0;
#endif
                        /* Subtract in timeval, so the fractions of a second
                         * are rounded to the whole specific time. */
                        timeval_subtract(&tv, &dest, &now);
                } else {
#ifndef S_SPLINT_S
                        tv.tv_sec = worker->env.cfg->stat_interval;
                        tv.tv_usec = 0;
#endif
                }
                comm_timer_set(worker->stat_timer, &tv);
        }
}

void worker_stat_timer_cb(void* arg)
{
        struct worker* worker = (struct worker*)arg;
        server_stats_log(&worker->stats, worker, worker->thread_num);
        mesh_stats(worker->env.mesh, "mesh has");
        worker_mem_report(worker, NULL);
        /* SHM is enabled, process data to SHM */
        if (worker->daemon->cfg->shm_enable) {
                shm_main_run(worker);
        }
        if(!worker->daemon->cfg->stat_cumulative) {
                worker_stats_clear(worker);
        }
        /* start next timer */
        worker_restart_timer(worker);
}

void worker_probe_timer_cb(void* arg)
{
        struct worker* worker = (struct worker*)arg;
        struct timeval tv;
#ifndef S_SPLINT_S
        tv.tv_sec = (time_t)autr_probe_timer(&worker->env);
        tv.tv_usec = 0;
#endif
        if(tv.tv_sec != 0)
                comm_timer_set(worker->env.probe_timer, &tv);
}

struct worker*
worker_create(struct daemon* daemon, int id)
{
        unsigned int seed;
        struct worker* worker = (struct worker*)calloc(1,
                sizeof(struct worker));
        if(!worker)
                return NULL;
        worker->daemon = daemon;
        worker->thread_num = id;
        if(!(worker->cmd = tube_create())) {
                free(worker);
                return NULL;
        }
        /* create random state here to avoid locking trouble in RAND_bytes */
        if(!(worker->rndstate = ub_initstate(daemon->rand))) {
                log_err("could not init random numbers.");
                tube_delete(worker->cmd);
                free(worker);
                return NULL;
        }
        explicit_bzero(&seed, sizeof(seed));
        return worker;
}

int
worker_init(struct worker* worker, struct config_file *cfg,
        struct listen_port* ports, int do_sigs)
{
#ifdef USE_DNSTAP
        struct dt_env* dtenv = &worker->dtenv;
#else
        void* dtenv = NULL;
#endif
        worker->need_to_exit = 0;
        worker->base = comm_base_create(do_sigs);
        if(!worker->base) {
                log_err("could not create event handling base");
                worker_delete(worker);
                return 0;
        }
        comm_base_set_slow_accept_handlers(worker->base, &worker_stop_accept,
                &worker_start_accept, worker);
        if(do_sigs) {
#ifdef SIGHUP
                ub_thread_sig_unblock(SIGHUP);
#endif
#ifdef SIGBREAK
                ub_thread_sig_unblock(SIGBREAK);
#endif
                ub_thread_sig_unblock(SIGINT);
#ifdef SIGQUIT
                ub_thread_sig_unblock(SIGQUIT);
#endif
                ub_thread_sig_unblock(SIGTERM);
#ifndef LIBEVENT_SIGNAL_PROBLEM
                worker->comsig = comm_signal_create(worker->base,
                        worker_sighandler, worker);
                if(!worker->comsig
#ifdef SIGHUP
                        || !comm_signal_bind(worker->comsig, SIGHUP)
#endif
#ifdef SIGQUIT
                        || !comm_signal_bind(worker->comsig, SIGQUIT)
#endif
                        || !comm_signal_bind(worker->comsig, SIGTERM)
#ifdef SIGBREAK
                        || !comm_signal_bind(worker->comsig, SIGBREAK)
#endif
                        || !comm_signal_bind(worker->comsig, SIGINT)) {
                        log_err("could not create signal handlers");
                        worker_delete(worker);
                        return 0;
                }
#endif /* LIBEVENT_SIGNAL_PROBLEM */
                if(!daemon_remote_open_accept(worker->daemon->rc,
                        worker->daemon->rc_ports, worker)) {
                        worker_delete(worker);
                        return 0;
                }
#ifdef UB_ON_WINDOWS
                wsvc_setup_worker(worker);
#endif /* UB_ON_WINDOWS */
        } else { /* !do_sigs */
                worker->comsig = NULL;
        }
#ifdef USE_DNSTAP
        if(cfg->dnstap) {
                log_assert(worker->daemon->dtenv != NULL);
                memcpy(&worker->dtenv, worker->daemon->dtenv, sizeof(struct dt_env));
                if(!dt_init(&worker->dtenv, worker->base))
                        fatal_exit("dt_init failed");
        }
#endif
        worker->front = listen_create(worker->base, ports,
                cfg->msg_buffer_size, (int)cfg->incoming_num_tcp,
                cfg->do_tcp_keepalive
                        ? cfg->tcp_keepalive_timeout
                        : cfg->tcp_idle_timeout,
                cfg->harden_large_queries, cfg->http_max_streams,
                cfg->http_endpoint, cfg->http_notls_downstream,
                worker->daemon->tcl, worker->daemon->listen_dot_sslctx,
                worker->daemon->listen_doh_sslctx,
                worker->daemon->listen_quic_sslctx,
                dtenv, worker->daemon->doq_table, worker->env.rnd,
                cfg, worker_handle_request, worker);
        if(!worker->front) {
                log_err("could not create listening sockets");
                worker_delete(worker);
                return 0;
        }
        worker->back = outside_network_create(worker->base,
                cfg->msg_buffer_size, (size_t)cfg->outgoing_num_ports,
                cfg->out_ifs, cfg->num_out_ifs, cfg->do_ip4, cfg->do_ip6,
                cfg->do_tcp?cfg->outgoing_num_tcp:0, cfg->ip_dscp,
                worker->daemon->env->infra_cache, worker->rndstate,
                cfg->use_caps_bits_for_id,
                cfg->unwanted_threshold, cfg->outgoing_tcp_mss,
                &worker_alloc_cleanup, worker,
                cfg->do_udp || cfg->udp_upstream_without_downstream,
                worker->daemon->connect_dot_sslctx, cfg->delay_close,
                cfg->tls_use_sni, dtenv, cfg->udp_connect,
                cfg->max_reuse_tcp_queries, cfg->tcp_reuse_timeout,
                cfg->tcp_auth_query_timeout, worker->daemon->shared_ports);
        if(!worker->back) {
                log_err("could not create outgoing sockets");
                worker_delete(worker);
                return 0;
        }
        iterator_set_ip46_support(&worker->daemon->mods, worker->daemon->env,
                worker->back);
        /* start listening to commands */
        if(!tube_setup_bg_listen(worker->cmd, worker->base,
                &worker_handle_control_cmd, worker)) {
                log_err("could not create control compt.");
                worker_delete(worker);
                return 0;
        }
        worker->stat_timer = comm_timer_create(worker->base,
                worker_stat_timer_cb, worker);
        if(!worker->stat_timer) {
                log_err("could not create statistics timer");
        }

        /* we use the msg_buffer_size as a good estimate for what the
         * user wants for memory usage sizes */
        worker->scratchpad = regional_create_custom(cfg->msg_buffer_size);
        if(!worker->scratchpad) {
                log_err("malloc failure");
                worker_delete(worker);
                return 0;
        }

        server_stats_init(&worker->stats, cfg);
        worker->alloc = worker->daemon->worker_allocs[worker->thread_num];
        alloc_set_id_cleanup(worker->alloc, &worker_alloc_cleanup, worker);
        worker->env = *worker->daemon->env;
        comm_base_timept(worker->base, &worker->env.now, &worker->env.now_tv);
        worker->env.worker = worker;
        worker->env.worker_base = worker->base;
        worker->env.send_query = &worker_send_query;
        worker->env.alloc = worker->alloc;
        worker->env.outnet = worker->back;
        worker->env.rnd = worker->rndstate;
        /* If case prefetch is triggered, the corresponding mesh will clear
         * the scratchpad for the module env in the middle of request handling.
         * It would be prone to a use-after-free kind of bug, so we avoid
         * sharing it with worker's own scratchpad at the cost of having
         * one more pad per worker. */
        worker->env.scratch = regional_create_custom(cfg->msg_buffer_size);
        if(!worker->env.scratch) {
                log_err("malloc failure");
                worker_delete(worker);
                return 0;
        }
        worker->env.mesh = mesh_create(&worker->daemon->mods, &worker->env);
        if(!worker->env.mesh) {
                log_err("malloc failure");
                worker_delete(worker);
                return 0;
        }
        /* Pass on daemon variables that we would need in the mesh area */
        worker->env.mesh->use_response_ip = worker->daemon->use_response_ip;
        worker->env.mesh->use_rpz = worker->daemon->use_rpz;

        worker->env.detach_subs = &mesh_detach_subs;
        worker->env.attach_sub = &mesh_attach_sub;
        worker->env.add_sub = &mesh_add_sub;
        worker->env.kill_sub = &mesh_state_delete;
        worker->env.detect_cycle = &mesh_detect_cycle;
        worker->env.scratch_buffer = sldns_buffer_new(cfg->msg_buffer_size);
        if(!worker->env.scratch_buffer) {
                log_err("malloc failure");
                worker_delete(worker);
                return 0;
        }
        /* one probe timer per process -- if we have 5011 anchors */
        if(autr_get_num_anchors(worker->env.anchors) > 0
#ifndef THREADS_DISABLED
                && worker->thread_num == 0
#endif
                ) {
                struct timeval tv;
                tv.tv_sec = 0;
                tv.tv_usec = 0;
                worker->env.probe_timer = comm_timer_create(worker->base,
                        worker_probe_timer_cb, worker);
                if(!worker->env.probe_timer) {
                        log_err("could not create 5011-probe timer");
                } else {
                        /* let timer fire, then it can reset itself */
                        comm_timer_set(worker->env.probe_timer, &tv);
                }
        }
        /* zone transfer tasks, setup once per process, if any */
        if(worker->env.auth_zones
#ifndef THREADS_DISABLED
                && worker->thread_num == 0
#endif
                ) {
                auth_xfer_pickup_initial(worker->env.auth_zones, &worker->env);
                auth_zones_pickup_zonemd_verify(worker->env.auth_zones,
                        &worker->env);
        }
#ifdef USE_DNSTAP
        if(worker->daemon->cfg->dnstap
#ifndef THREADS_DISABLED
                && worker->thread_num == 0
#endif
                ) {
                if(!dt_io_thread_start(dtenv->dtio, comm_base_internal(
                        worker->base), worker->daemon->num)) {
                        log_err("could not start dnstap io thread");
                        worker_delete(worker);
                        return 0;
                }
        }
#endif /* USE_DNSTAP */
        worker_mem_report(worker, NULL);
        /* if statistics enabled start timer */
        if(worker->env.cfg->stat_interval > 0) {
                verbose(VERB_ALGO, "set statistics interval %d secs",
                        worker->env.cfg->stat_interval);
                worker_restart_timer(worker);
        }
        pp_init(&sldns_write_uint16, &sldns_write_uint32);
        return 1;
}

void
worker_work(struct worker* worker)
{
        comm_base_dispatch(worker->base);
}

void
worker_delete(struct worker* worker)
{
        if(!worker)
                return;
        if(worker->env.mesh && verbosity >= VERB_OPS) {
                server_stats_log(&worker->stats, worker, worker->thread_num);
                mesh_stats(worker->env.mesh, "mesh has");
                worker_mem_report(worker, NULL);
        }
        outside_network_quit_prepare(worker->back);
        mesh_delete(worker->env.mesh);
        sldns_buffer_free(worker->env.scratch_buffer);
        listen_delete(worker->front);
        outside_network_delete(worker->back);
        comm_signal_delete(worker->comsig);
        tube_delete(worker->cmd);
        comm_timer_delete(worker->stat_timer);
        comm_timer_delete(worker->env.probe_timer);
        if(worker->thread_num == 0) {
#ifdef UB_ON_WINDOWS
                wsvc_desetup_worker(worker);
#endif /* UB_ON_WINDOWS */
        }
#ifdef USE_DNSTAP
        if(worker->daemon->cfg->dnstap
#ifndef THREADS_DISABLED
                && worker->thread_num == 0
#endif
                ) {
                dt_io_thread_stop(worker->dtenv.dtio);
        }
        dt_deinit(&worker->dtenv);
#endif /* USE_DNSTAP */
        comm_base_delete(worker->base);
        ub_randfree(worker->rndstate);
        /* don't touch worker->alloc, as it's maintained in daemon */
        regional_destroy(worker->env.scratch);
        regional_destroy(worker->scratchpad);
        free(worker);
}

struct outbound_entry*
worker_send_query(struct query_info* qinfo, uint16_t flags, int dnssec,
        int want_dnssec, int nocaps, int check_ratelimit,
        struct sockaddr_storage* addr, socklen_t addrlen, uint8_t* zone,
        size_t zonelen, int tcp_upstream, int ssl_upstream, char* tls_auth_name,
        struct module_qstate* q, int* was_ratelimited)
{
        struct worker* worker = q->env->worker;
        struct outbound_entry* e = (struct outbound_entry*)regional_alloc(
                q->region, sizeof(*e));
        if(!e)
                return NULL;
        e->qstate = q;
        e->qsent = outnet_serviced_query(worker->back, qinfo, flags, dnssec,
                want_dnssec, nocaps, check_ratelimit, tcp_upstream,
                ssl_upstream, tls_auth_name, addr, addrlen, zone, zonelen, q,
                worker_handle_service_reply, e, worker->back->udp_buff, q->env,
                was_ratelimited);
        if(!e->qsent) {
                return NULL;
        }
        return e;
}

void
worker_alloc_cleanup(void* arg)
{
        struct worker* worker = (struct worker*)arg;
        slabhash_clear(&worker->env.rrset_cache->table);
        slabhash_clear(worker->env.msg_cache);
}

void worker_stats_clear(struct worker* worker)
{
        server_stats_init(&worker->stats, worker->env.cfg);
        mesh_stats_clear(worker->env.mesh);
        worker->back->unwanted_replies = 0;
        worker->back->num_tcp_outgoing = 0;
        worker->back->num_udp_outgoing = 0;
}

void worker_start_accept(void* arg)
{
        struct worker* worker = (struct worker*)arg;
        listen_start_accept(worker->front);
        if(worker->thread_num == 0)
                daemon_remote_start_accept(worker->daemon->rc);
}

void worker_stop_accept(void* arg)
{
        struct worker* worker = (struct worker*)arg;
        listen_stop_accept(worker->front);
        if(worker->thread_num == 0)
                daemon_remote_stop_accept(worker->daemon->rc);
}

/* --- fake callbacks for fptr_wlist to work --- */
struct outbound_entry* libworker_send_query(
        struct query_info* ATTR_UNUSED(qinfo),
        uint16_t ATTR_UNUSED(flags), int ATTR_UNUSED(dnssec),
        int ATTR_UNUSED(want_dnssec), int ATTR_UNUSED(nocaps),
        int ATTR_UNUSED(check_ratelimit),
        struct sockaddr_storage* ATTR_UNUSED(addr), socklen_t ATTR_UNUSED(addrlen),
        uint8_t* ATTR_UNUSED(zone), size_t ATTR_UNUSED(zonelen), int ATTR_UNUSED(tcp_upstream),
        int ATTR_UNUSED(ssl_upstream), char* ATTR_UNUSED(tls_auth_name),
        struct module_qstate* ATTR_UNUSED(q), int* ATTR_UNUSED(was_ratelimited))
{
        log_assert(0);
        return 0;
}

int libworker_handle_service_reply(struct comm_point* ATTR_UNUSED(c),
        void* ATTR_UNUSED(arg), int ATTR_UNUSED(error),
        struct comm_reply* ATTR_UNUSED(reply_info))
{
        log_assert(0);
        return 0;
}

void libworker_handle_control_cmd(struct tube* ATTR_UNUSED(tube),
        uint8_t* ATTR_UNUSED(buffer), size_t ATTR_UNUSED(len),
        int ATTR_UNUSED(error), void* ATTR_UNUSED(arg))
{
        log_assert(0);
}

void libworker_fg_done_cb(void* ATTR_UNUSED(arg), int ATTR_UNUSED(rcode),
        sldns_buffer* ATTR_UNUSED(buf), enum sec_status ATTR_UNUSED(s),
        char* ATTR_UNUSED(why_bogus), int ATTR_UNUSED(was_ratelimited))
{
        log_assert(0);
}

void libworker_bg_done_cb(void* ATTR_UNUSED(arg), int ATTR_UNUSED(rcode),
        sldns_buffer* ATTR_UNUSED(buf), enum sec_status ATTR_UNUSED(s),
        char* ATTR_UNUSED(why_bogus), int ATTR_UNUSED(was_ratelimited))
{
        log_assert(0);
}

void libworker_event_done_cb(void* ATTR_UNUSED(arg), int ATTR_UNUSED(rcode),
        sldns_buffer* ATTR_UNUSED(buf), enum sec_status ATTR_UNUSED(s),
        char* ATTR_UNUSED(why_bogus), int ATTR_UNUSED(was_ratelimited))
{
        log_assert(0);
}

void libworker_alloc_cleanup(void* ATTR_UNUSED(arg))
{
        log_assert(0);
}

int context_query_cmp(const void* ATTR_UNUSED(a), const void* ATTR_UNUSED(b))
{
        log_assert(0);
        return 0;
}

int order_lock_cmp(const void* ATTR_UNUSED(e1), const void* ATTR_UNUSED(e2))
{
        log_assert(0);
        return 0;
}

int codeline_cmp(const void* ATTR_UNUSED(a), const void* ATTR_UNUSED(b))
{
        log_assert(0);
        return 0;
}

#ifdef USE_DNSTAP
void dtio_tap_callback(int ATTR_UNUSED(fd), short ATTR_UNUSED(ev),
        void* ATTR_UNUSED(arg))
{
        log_assert(0);
}
#endif

#ifdef USE_DNSTAP
void dtio_mainfdcallback(int ATTR_UNUSED(fd), short ATTR_UNUSED(ev),
        void* ATTR_UNUSED(arg))
{
        log_assert(0);
}
#endif

#ifdef HAVE_NGTCP2
void doq_client_event_cb(int ATTR_UNUSED(fd), short ATTR_UNUSED(ev),
        void* ATTR_UNUSED(arg))
{
        log_assert(0);
}
#endif

#ifdef HAVE_NGTCP2
void doq_client_timer_cb(int ATTR_UNUSED(fd), short ATTR_UNUSED(ev),
        void* ATTR_UNUSED(arg))
{
        log_assert(0);
}
#endif