/*
 * libunbound/worker.c - worker thread or process that resolves
 *
 * Copyright (c) 2007, NLnet Labs. All rights reserved.
 *
 * This software is open source.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * Neither the name of the NLNET LABS nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * \file
 *
 * This file contains the worker process or thread that performs
 * the DNS resolving and validation. The worker is called by a procedure
 * and if in the background continues until exit, if in the foreground
 * returns from the procedure when done.
 */
#include "config.h"
#ifdef HAVE_SSL
#include <openssl/ssl.h>
#endif
#include "libunbound/libworker.h"
#include "libunbound/context.h"
#include "libunbound/unbound.h"
#include "libunbound/worker.h"
#include "libunbound/unbound-event.h"
#include "services/outside_network.h"
#include "services/mesh.h"
#include "services/localzone.h"
#include "services/cache/rrset.h"
#include "services/outbound_list.h"
#include "services/authzone.h"
#include "util/fptr_wlist.h"
#include "util/module.h"
#include "util/regional.h"
#include "util/random.h"
#include "util/config_file.h"
#include "util/netevent.h"
#include "util/proxy_protocol.h"
#include "util/storage/lookup3.h"
#include "util/storage/slabhash.h"
#include "util/net_help.h"
#include "util/data/dname.h"
#include "util/data/msgreply.h"
#include "util/data/msgencode.h"
#include "util/tube.h"
#include "sldns/sbuffer.h"
#include "sldns/str2wire.h"
#ifdef USE_DNSTAP
#include "dnstap/dtstream.h"
#endif

#ifdef HAVE_TARGETCONDITIONALS_H
#include <TargetConditionals.h>
#endif

#if (defined(TARGET_OS_TV) && TARGET_OS_TV) || (defined(TARGET_OS_WATCH) && TARGET_OS_WATCH)
#undef HAVE_FORK
#endif

/** handle new query command for bg worker */
static void handle_newq(struct libworker* w, uint8_t* buf, uint32_t len);

/** delete libworker env */
static void
libworker_delete_env(struct libworker* w)
{
        if(w->env) {
                outside_network_quit_prepare(w->back);
                mesh_delete(w->env->mesh);
                context_release_alloc(w->ctx, w->env->alloc, 
                        !w->is_bg || w->is_bg_thread);
                sldns_buffer_free(w->env->scratch_buffer);
                regional_destroy(w->env->scratch);
                ub_randfree(w->env->rnd);
                free(w->env);
        }
#ifdef HAVE_SSL
        SSL_CTX_free(w->sslctx);
#endif
        outside_network_delete(w->back);
}

/** delete libworker struct */
static void
libworker_delete(struct libworker* w)
{
        if(!w) return;
        libworker_delete_env(w);
        comm_base_delete(w->base);
        free(w);
}

void
libworker_delete_event(struct libworker* w)
{
        if(!w) return;
        libworker_delete_env(w);
        comm_base_delete_no_base(w->base);
        free(w);
}

/** setup fresh libworker struct */
static struct libworker*
libworker_setup(struct ub_ctx* ctx, int is_bg, struct ub_event_base* eb)
{
        struct libworker* w = (struct libworker*)calloc(1, sizeof(*w));
        struct config_file* cfg = ctx->env->cfg;
        int* ports;
        int numports;
        if(!w) return NULL;
        w->is_bg = is_bg;
        w->ctx = ctx;
        w->env = (struct module_env*)malloc(sizeof(*w->env));
        if(!w->env) {
                free(w);
                return NULL;
        }
        *w->env = *ctx->env;
        w->env->alloc = context_obtain_alloc(ctx, !w->is_bg || w->is_bg_thread);
        if(!w->env->alloc) {
                libworker_delete(w);
                return NULL;
        }
        w->thread_num = w->env->alloc->thread_num;
        alloc_set_id_cleanup(w->env->alloc, &libworker_alloc_cleanup, w);
        if(!w->is_bg || w->is_bg_thread) {
                lock_basic_lock(&ctx->cfglock);
        }
        w->env->scratch = regional_create_custom(cfg->msg_buffer_size);
        w->env->scratch_buffer = sldns_buffer_new(cfg->msg_buffer_size);
#ifdef HAVE_SSL
        w->sslctx = connect_sslctx_create(NULL, NULL,
                cfg->tls_cert_bundle, cfg->tls_win_cert);
        if(!w->sslctx) {
                /* to make the setup fail after unlock */
                sldns_buffer_free(w->env->scratch_buffer);
                w->env->scratch_buffer = NULL;
        }
#endif
        if(!w->is_bg || w->is_bg_thread) {
                lock_basic_unlock(&ctx->cfglock);
        }
        if(!w->env->scratch || !w->env->scratch_buffer) {
                libworker_delete(w);
                return NULL;
        }
        w->env->worker = (struct worker*)w;
        w->env->probe_timer = NULL;
        if(!w->is_bg || w->is_bg_thread) {
                lock_basic_lock(&ctx->cfglock);
        }
        if(!(w->env->rnd = ub_initstate(ctx->seed_rnd))) {
                if(!w->is_bg || w->is_bg_thread) {
                        lock_basic_unlock(&ctx->cfglock);
                }
                libworker_delete(w);
                return NULL;
        }
        if(!w->is_bg || w->is_bg_thread) {
                lock_basic_unlock(&ctx->cfglock);
        }
        if(1) {
                /* primitive lockout for threading: if it overwrites another
                 * thread it is like wiping the cache (which is likely empty
                 * at the start) */
                /* note we are holding the ctx lock in normal threaded
                 * cases so that is solved properly, it is only for many ctx
                 * in different threads that this may clash */
                static int done_raninit = 0;
                if(!done_raninit) {
                        done_raninit = 1;
                        hash_set_raninit((uint32_t)ub_random(w->env->rnd));
                }
        }

        if(eb)
                w->base = comm_base_create_event(eb);
        else    w->base = comm_base_create(0);
        if(!w->base) {
                libworker_delete(w);
                return NULL;
        }
        w->env->worker_base = w->base;
        if(!w->is_bg || w->is_bg_thread) {
                lock_basic_lock(&ctx->cfglock);
        }
        numports = cfg_condense_ports(cfg, &ports);
        if(numports == 0) {
                if(!w->is_bg || w->is_bg_thread) {
                        lock_basic_unlock(&ctx->cfglock);
                }
                libworker_delete(w);
                return NULL;
        }
        w->back = outside_network_create(w->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,
                w->env->infra_cache, w->env->rnd, cfg->use_caps_bits_for_id,
                ports, numports, cfg->unwanted_threshold,
                cfg->outgoing_tcp_mss, &libworker_alloc_cleanup, w,
                cfg->do_udp || cfg->udp_upstream_without_downstream, w->sslctx,
                cfg->delay_close, cfg->tls_use_sni, NULL, cfg->udp_connect,
                cfg->max_reuse_tcp_queries, cfg->tcp_reuse_timeout,
                cfg->tcp_auth_query_timeout);
        w->env->outnet = w->back;
        if(!w->is_bg || w->is_bg_thread) {
                lock_basic_unlock(&ctx->cfglock);
        }
        free(ports);
        if(!w->back) {
                libworker_delete(w);
                return NULL;
        }
        w->env->mesh = mesh_create(&ctx->mods, w->env);
        if(!w->env->mesh) {
                libworker_delete(w);
                return NULL;
        }
        w->env->send_query = &libworker_send_query;
        w->env->detach_subs = &mesh_detach_subs;
        w->env->attach_sub = &mesh_attach_sub;
        w->env->add_sub = &mesh_add_sub;
        w->env->kill_sub = &mesh_state_delete;
        w->env->detect_cycle = &mesh_detect_cycle;
        comm_base_timept(w->base, &w->env->now, &w->env->now_tv);
        pp_init(&sldns_write_uint16, &sldns_write_uint32);
        return w;
}

struct libworker* libworker_create_event(struct ub_ctx* ctx,
        struct ub_event_base* eb)
{
        return libworker_setup(ctx, 0, eb);
}

/** handle cancel command for bg worker */
static void
handle_cancel(struct libworker* w, uint8_t* buf, uint32_t len)
{
        struct ctx_query* q;
        if(w->is_bg_thread) {
                lock_basic_lock(&w->ctx->cfglock);
                q = context_deserialize_cancel(w->ctx, buf, len);
                lock_basic_unlock(&w->ctx->cfglock);
        } else {
                q = context_deserialize_cancel(w->ctx, buf, len);
        }
        if(!q) {
                /* probably simply lookup failed, i.e. the message had been
                 * processed and answered before the cancel arrived */
                return;
        }
        q->cancelled = 1;
        free(buf);
}

/** do control command coming into bg server */
static void
libworker_do_cmd(struct libworker* w, uint8_t* msg, uint32_t len)
{
        switch(context_serial_getcmd(msg, len)) {
                default:
                case UB_LIBCMD_ANSWER:
                        log_err("unknown command for bg worker %d", 
                                (int)context_serial_getcmd(msg, len));
                        /* and fall through to quit */
                        ATTR_FALLTHROUGH
                        /* fallthrough */
                case UB_LIBCMD_QUIT:
                        free(msg);
                        comm_base_exit(w->base);
                        break;
                case UB_LIBCMD_NEWQUERY:
                        handle_newq(w, msg, len);
                        break;
                case UB_LIBCMD_CANCEL:
                        handle_cancel(w, msg, len);
                        break;
        }
}

/** handle control command coming into server */
void 
libworker_handle_control_cmd(struct tube* ATTR_UNUSED(tube), 
        uint8_t* msg, size_t len, int err, void* arg)
{
        struct libworker* w = (struct libworker*)arg;

        if(err != 0) {
                free(msg);
                /* it is of no use to go on, exit */
                comm_base_exit(w->base);
                return;
        }
        libworker_do_cmd(w, msg, len); /* also frees the buf */
}

/** the background thread func */
static void*
libworker_dobg(void* arg)
{
        /* setup */
        uint32_t m;
        struct libworker* w = (struct libworker*)arg;
        struct ub_ctx* ctx;
        if(!w) {
                log_err("libunbound bg worker init failed, nomem");
                return NULL;
        }
        ctx = w->ctx;
        log_thread_set(&w->thread_num);
#ifdef THREADS_DISABLED
        /* we are forked */
        w->is_bg_thread = 0;
        /* close non-used parts of the pipes */
        tube_close_write(ctx->qq_pipe);
        tube_close_read(ctx->rr_pipe);
#endif
        if(!tube_setup_bg_listen(ctx->qq_pipe, w->base, 
                libworker_handle_control_cmd, w)) {
                log_err("libunbound bg worker init failed, no bglisten");
                return NULL;
        }
        if(!tube_setup_bg_write(ctx->rr_pipe, w->base)) {
                log_err("libunbound bg worker init failed, no bgwrite");
                return NULL;
        }

        /* do the work */
        comm_base_dispatch(w->base);

        /* cleanup */
        m = UB_LIBCMD_QUIT;
        w->want_quit = 1;
        tube_remove_bg_listen(w->ctx->qq_pipe);
        tube_remove_bg_write(w->ctx->rr_pipe);
        libworker_delete(w);
        (void)tube_write_msg(ctx->rr_pipe, (uint8_t*)&m, 
                (uint32_t)sizeof(m), 0);
#ifdef THREADS_DISABLED
        /* close pipes from forked process before exit */
        tube_close_read(ctx->qq_pipe);
        tube_close_write(ctx->rr_pipe);
#endif
        return NULL;
}

int libworker_bg(struct ub_ctx* ctx)
{
        struct libworker* w;
        /* fork or threadcreate */
        lock_basic_lock(&ctx->cfglock);
        if(ctx->dothread) {
                lock_basic_unlock(&ctx->cfglock);
                w = libworker_setup(ctx, 1, NULL);
                if(!w) return UB_NOMEM;
                w->is_bg_thread = 1;
                ctx->thread_worker = w;
#ifdef ENABLE_LOCK_CHECKS
                w->thread_num = 1; /* for nicer DEBUG checklocks */
#endif
                ub_thread_create(&ctx->bg_tid, libworker_dobg, w);
        } else {
                lock_basic_unlock(&ctx->cfglock);
#ifndef HAVE_FORK
                /* no fork on windows */
                return UB_FORKFAIL;
#else /* HAVE_FORK */
                switch((ctx->bg_pid=fork())) {
                        case 0:
                                w = libworker_setup(ctx, 1, NULL);
                                if(!w) fatal_exit("out of memory");
                                /* close non-used parts of the pipes */
                                tube_close_write(ctx->qq_pipe);
                                tube_close_read(ctx->rr_pipe);
                                (void)libworker_dobg(w);
                                exit(0);
                                break;
                        case -1:
                                return UB_FORKFAIL;
                        default:
                                /* close non-used parts, so that the worker
                                 * bgprocess gets 'pipe closed' when the
                                 * main process exits */
                                tube_close_read(ctx->qq_pipe);
                                tube_close_write(ctx->rr_pipe);
                                break;
                }
#endif /* HAVE_FORK */ 
        }
        return UB_NOERROR;
}

/** insert canonname */
static int
fill_canon(struct ub_result* res, uint8_t* s)
{
        char buf[LDNS_MAX_DOMAINLEN];
        dname_str(s, buf);
        res->canonname = strdup(buf);
        return res->canonname != 0;
}

/** fill data into result */
static int
fill_res(struct ub_result* res, struct ub_packed_rrset_key* answer,
        uint8_t* finalcname, struct query_info* rq, struct reply_info* rep)
{
        size_t i;
        struct packed_rrset_data* data;
        res->ttl = 0;
        if(!answer) {
                if(finalcname) {
                        if(!fill_canon(res, finalcname))
                                return 0; /* out of memory */
                }
                if(rep->rrset_count != 0)
                        res->ttl = (int)rep->ttl;
                res->data = (char**)calloc(1, sizeof(char*));
                if(!res->data)
                        return 0; /* out of memory */
                res->len = (int*)calloc(1, sizeof(int));
                if(!res->len) {
                        free(res->data);
                        res->data = NULL;
                        return 0; /* out of memory */
                }
                return 1;
        }
        data = (struct packed_rrset_data*)answer->entry.data;
        if(query_dname_compare(rq->qname, answer->rk.dname) != 0) {
                if(!fill_canon(res, answer->rk.dname))
                        return 0; /* out of memory */
        } else  res->canonname = NULL;
        res->data = (char**)calloc(data->count+1, sizeof(char*));
        if(!res->data)
                return 0; /* out of memory */
        res->len = (int*)calloc(data->count+1, sizeof(int));
        if(!res->len) {
                free(res->data);
                res->data = NULL;
                return 0; /* out of memory */
        }
        for(i=0; i<data->count; i++) {
                /* remove rdlength from rdata */
                res->len[i] = (int)(data->rr_len[i] - 2);
                res->data[i] = memdup(data->rr_data[i]+2, (size_t)res->len[i]);
                if(!res->data[i]) {
                        size_t j;
                        for(j=0; j<i; j++) {
                                free(res->data[j]);
                                res->data[j] = NULL;
                        }
                        free(res->data);
                        res->data = NULL;
                        free(res->len);
                        res->len = NULL;
                        return 0; /* out of memory */
                }
        }
        /* ttl for positive answers, from CNAME and answer RRs */
        if(data->count != 0) {
                size_t j;
                res->ttl = (int)data->ttl;
                for(j=0; j<rep->an_numrrsets; j++) {
                        struct packed_rrset_data* d =
                                (struct packed_rrset_data*)rep->rrsets[j]->
                                entry.data;
                        if((int)d->ttl < res->ttl)
                                res->ttl = (int)d->ttl;
                }
        }
        /* ttl for negative answers */
        if(data->count == 0 && rep->rrset_count != 0)
                res->ttl = (int)rep->ttl;
        res->data[data->count] = NULL;
        res->len[data->count] = 0;
        return 1;
}

/** fill result from parsed message, on error fills servfail */
void
libworker_enter_result(struct ub_result* res, sldns_buffer* buf,
        struct regional* temp, enum sec_status msg_security)
{
        struct query_info rq;
        struct reply_info* rep;
        res->rcode = LDNS_RCODE_SERVFAIL;
        rep = parse_reply_in_temp_region(buf, temp, &rq);
        if(!rep) {
                log_err("cannot parse buf");
                return; /* error parsing buf, or out of memory */
        }
        if(!fill_res(res, reply_find_answer_rrset(&rq, rep), 
                reply_find_final_cname_target(&rq, rep), &rq, rep))
                return; /* out of memory */
        /* rcode, havedata, nxdomain, secure, bogus */
        res->rcode = (int)FLAGS_GET_RCODE(rep->flags);
        if(res->data && res->data[0])
                res->havedata = 1;
        if(res->rcode == LDNS_RCODE_NXDOMAIN)
                res->nxdomain = 1;
        if(msg_security == sec_status_secure)
                res->secure = 1;
        if(msg_security == sec_status_bogus ||
                msg_security == sec_status_secure_sentinel_fail)
                res->bogus = 1;
}

/** fillup fg results */
static void
libworker_fillup_fg(struct ctx_query* q, int rcode, sldns_buffer* buf, 
        enum sec_status s, char* why_bogus, int was_ratelimited)
{
        q->res->was_ratelimited = was_ratelimited;
        if(why_bogus)
                q->res->why_bogus = strdup(why_bogus);
        if(rcode != 0) {
                q->res->rcode = rcode;
                q->msg_security = s;
                return;
        }

        q->res->rcode = LDNS_RCODE_SERVFAIL;
        q->msg_security = sec_status_unchecked;
        q->msg = memdup(sldns_buffer_begin(buf), sldns_buffer_limit(buf));
        q->msg_len = sldns_buffer_limit(buf);
        if(!q->msg) {
                return; /* the error is in the rcode */
        }

        /* canonname and results */
        q->msg_security = s;
        libworker_enter_result(q->res, buf, q->w->env->scratch, s);
}

void
libworker_fg_done_cb(void* arg, int rcode, sldns_buffer* buf, enum sec_status s,
        char* why_bogus, int was_ratelimited)
{
        struct ctx_query* q = (struct ctx_query*)arg;
        /* fg query is done; exit comm base */
        comm_base_exit(q->w->base);

        libworker_fillup_fg(q, rcode, buf, s, why_bogus, was_ratelimited);
}

/** setup qinfo and edns */
static int
setup_qinfo_edns(struct libworker* w, struct ctx_query* q, 
        struct query_info* qinfo, struct edns_data* edns)
{
        qinfo->qtype = (uint16_t)q->res->qtype;
        qinfo->qclass = (uint16_t)q->res->qclass;
        qinfo->local_alias = NULL;
        qinfo->qname = sldns_str2wire_dname(q->res->qname, &qinfo->qname_len);
        if(!qinfo->qname) {
                return 0;
        }
        edns->edns_present = 1;
        edns->ext_rcode = 0;
        edns->edns_version = 0;
        edns->bits = EDNS_DO;
        edns->opt_list_in = NULL;
        edns->opt_list_out = NULL;
        edns->opt_list_inplace_cb_out = NULL;
        edns->padding_block_size = 0;
        edns->cookie_present = 0;
        edns->cookie_valid = 0;
        if(sldns_buffer_capacity(w->back->udp_buff) < 65535)
                edns->udp_size = (uint16_t)sldns_buffer_capacity(
                        w->back->udp_buff);
        else    edns->udp_size = 65535;
        return 1;
}

int libworker_fg(struct ub_ctx* ctx, struct ctx_query* q)
{
        struct libworker* w = libworker_setup(ctx, 0, NULL);
        uint16_t qflags, qid;
        struct query_info qinfo;
        struct edns_data edns;
        if(!w)
                return UB_INITFAIL;
        if(!setup_qinfo_edns(w, q, &qinfo, &edns)) {
                libworker_delete(w);
                return UB_SYNTAX;
        }
        qid = 0;
        qflags = BIT_RD;
        q->w = w;
        /* see if there is a fixed answer */
        sldns_buffer_write_u16_at(w->back->udp_buff, 0, qid);
        sldns_buffer_write_u16_at(w->back->udp_buff, 2, qflags);
        if(local_zones_answer(ctx->local_zones, w->env, &qinfo, &edns, 
                w->back->udp_buff, w->env->scratch, NULL, NULL, 0, NULL, 0,
                NULL, 0, NULL, 0, NULL)) {
                regional_free_all(w->env->scratch);
                libworker_fillup_fg(q, LDNS_RCODE_NOERROR, 
                        w->back->udp_buff, sec_status_insecure, NULL, 0);
                libworker_delete(w);
                free(qinfo.qname);
                return UB_NOERROR;
        }
        if(ctx->env->auth_zones && auth_zones_downstream_answer(
                ctx->env->auth_zones, w->env, &qinfo, &edns, NULL,
                w->back->udp_buff, w->env->scratch)) {
                regional_free_all(w->env->scratch);
                libworker_fillup_fg(q, LDNS_RCODE_NOERROR, 
                        w->back->udp_buff, sec_status_insecure, NULL, 0);
                libworker_delete(w);
                free(qinfo.qname);
                return UB_NOERROR;
        }
        /* process new query */
        if(!mesh_new_callback(w->env->mesh, &qinfo, qflags, &edns, 
                w->back->udp_buff, qid, libworker_fg_done_cb, q, 0)) {
                free(qinfo.qname);
                return UB_NOMEM;
        }
        free(qinfo.qname);

        /* wait for reply */
        comm_base_dispatch(w->base);

        libworker_delete(w);
        return UB_NOERROR;
}

void
libworker_event_done_cb(void* arg, int rcode, sldns_buffer* buf,
        enum sec_status s, char* why_bogus, int was_ratelimited)
{
        struct ctx_query* q = (struct ctx_query*)arg;
        ub_event_callback_type cb = q->cb_event;
        void* cb_arg = q->cb_arg;
        int cancelled = q->cancelled;

        /* delete it now */
        struct ub_ctx* ctx = q->w->ctx;
        lock_basic_lock(&ctx->cfglock);
        (void)rbtree_delete(&ctx->queries, q->node.key);
        ctx->num_async--;
        context_query_delete(q);
        lock_basic_unlock(&ctx->cfglock);

        if(!cancelled) {
                /* call callback */
                int sec = 0;
                if(s == sec_status_bogus)
                        sec = 1;
                else if(s == sec_status_secure)
                        sec = 2;
                (*cb)(cb_arg, rcode, (buf?(void*)sldns_buffer_begin(buf):NULL),
                        (buf?(int)sldns_buffer_limit(buf):0), sec, why_bogus, was_ratelimited);
        }
}

int libworker_attach_mesh(struct ub_ctx* ctx, struct ctx_query* q,
        int* async_id)
{
        struct libworker* w = ctx->event_worker;
        uint16_t qflags, qid;
        struct query_info qinfo;
        struct edns_data edns;
        if(!w)
                return UB_INITFAIL;
        if(!setup_qinfo_edns(w, q, &qinfo, &edns))
                return UB_SYNTAX;
        qid = 0;
        qflags = BIT_RD;
        q->w = w;
        /* see if there is a fixed answer */
        sldns_buffer_write_u16_at(w->back->udp_buff, 0, qid);
        sldns_buffer_write_u16_at(w->back->udp_buff, 2, qflags);
        if(local_zones_answer(ctx->local_zones, w->env, &qinfo, &edns, 
                w->back->udp_buff, w->env->scratch, NULL, NULL, 0, NULL, 0,
                NULL, 0, NULL, 0, NULL)) {
                regional_free_all(w->env->scratch);
                free(qinfo.qname);
                libworker_event_done_cb(q, LDNS_RCODE_NOERROR,
                        w->back->udp_buff, sec_status_insecure, NULL, 0);
                return UB_NOERROR;
        }
        if(ctx->env->auth_zones && auth_zones_downstream_answer(
                ctx->env->auth_zones, w->env, &qinfo, &edns, NULL,
                w->back->udp_buff, w->env->scratch)) {
                regional_free_all(w->env->scratch);
                free(qinfo.qname);
                libworker_event_done_cb(q, LDNS_RCODE_NOERROR,
                        w->back->udp_buff, sec_status_insecure, NULL, 0);
                return UB_NOERROR;
        }
        /* process new query */
        if(async_id)
                *async_id = q->querynum;
        if(!mesh_new_callback(w->env->mesh, &qinfo, qflags, &edns, 
                w->back->udp_buff, qid, libworker_event_done_cb, q, 0)) {
                free(qinfo.qname);
                return UB_NOMEM;
        }
        free(qinfo.qname);
        return UB_NOERROR;
}

/** add result to the bg worker result queue */
static void
add_bg_result(struct libworker* w, struct ctx_query* q, sldns_buffer* pkt, 
        int err, char* reason, int was_ratelimited)
{
        uint8_t* msg = NULL;
        uint32_t len = 0;

        if(w->want_quit) {
                context_query_delete(q);
                return;
        }
        /* serialize and delete unneeded q */
        if(w->is_bg_thread) {
                lock_basic_lock(&w->ctx->cfglock);
                if(reason)
                        q->res->why_bogus = strdup(reason);
                q->res->was_ratelimited = was_ratelimited;
                if(pkt) {
                        q->msg_len = sldns_buffer_remaining(pkt);
                        q->msg = memdup(sldns_buffer_begin(pkt), q->msg_len);
                        if(!q->msg) {
                                msg = context_serialize_answer(q, UB_NOMEM, NULL, &len);
                        } else {
                                msg = context_serialize_answer(q, err, NULL, &len);
                        }
                } else {
                        msg = context_serialize_answer(q, err, NULL, &len);
                }
                lock_basic_unlock(&w->ctx->cfglock);
        } else {
                if(reason)
                        q->res->why_bogus = strdup(reason);
                q->res->was_ratelimited = was_ratelimited;
                msg = context_serialize_answer(q, err, pkt, &len);
                (void)rbtree_delete(&w->ctx->queries, q->node.key);
                w->ctx->num_async--;
                context_query_delete(q);
        }

        if(!msg) {
                log_err("out of memory for async answer");
                return;
        }
        if(!tube_queue_item(w->ctx->rr_pipe, msg, len)) {
                log_err("out of memory for async answer");
                return;
        }
}

void
libworker_bg_done_cb(void* arg, int rcode, sldns_buffer* buf, enum sec_status s,
        char* why_bogus, int was_ratelimited)
{
        struct ctx_query* q = (struct ctx_query*)arg;

        if(q->cancelled || q->w->back->want_to_quit) {
                if(q->w->is_bg_thread) {
                        /* delete it now */
                        struct ub_ctx* ctx = q->w->ctx;
                        lock_basic_lock(&ctx->cfglock);
                        (void)rbtree_delete(&ctx->queries, q->node.key);
                        ctx->num_async--;
                        context_query_delete(q);
                        lock_basic_unlock(&ctx->cfglock);
                }
                /* cancelled, do not give answer */
                return;
        }
        q->msg_security = s;
        if(!buf) {
                buf = q->w->env->scratch_buffer;
        }
        if(rcode != 0) {
                error_encode(buf, rcode, NULL, 0, BIT_RD, NULL);
        }
        add_bg_result(q->w, q, buf, UB_NOERROR, why_bogus, was_ratelimited);
}


/** handle new query command for bg worker */
static void
handle_newq(struct libworker* w, uint8_t* buf, uint32_t len)
{
        uint16_t qflags, qid;
        struct query_info qinfo;
        struct edns_data edns;
        struct ctx_query* q;
        if(w->is_bg_thread) {
                lock_basic_lock(&w->ctx->cfglock);
                q = context_lookup_new_query(w->ctx, buf, len);
                lock_basic_unlock(&w->ctx->cfglock);
        } else {
                q = context_deserialize_new_query(w->ctx, buf, len);
        }
        free(buf);
        if(!q) {
                log_err("failed to deserialize newq");
                return;
        }
        if(!setup_qinfo_edns(w, q, &qinfo, &edns)) {
                add_bg_result(w, q, NULL, UB_SYNTAX, NULL, 0);
                return;
        }
        qid = 0;
        qflags = BIT_RD;
        /* see if there is a fixed answer */
        sldns_buffer_write_u16_at(w->back->udp_buff, 0, qid);
        sldns_buffer_write_u16_at(w->back->udp_buff, 2, qflags);
        if(local_zones_answer(w->ctx->local_zones, w->env, &qinfo, &edns, 
                w->back->udp_buff, w->env->scratch, NULL, NULL, 0, NULL, 0,
                NULL, 0, NULL, 0, NULL)) {
                regional_free_all(w->env->scratch);
                q->msg_security = sec_status_insecure;
                add_bg_result(w, q, w->back->udp_buff, UB_NOERROR, NULL, 0);
                free(qinfo.qname);
                return;
        }
        if(w->ctx->env->auth_zones && auth_zones_downstream_answer(
                w->ctx->env->auth_zones, w->env, &qinfo, &edns, NULL,
                w->back->udp_buff, w->env->scratch)) {
                regional_free_all(w->env->scratch);
                q->msg_security = sec_status_insecure;
                add_bg_result(w, q, w->back->udp_buff, UB_NOERROR, NULL, 0);
                free(qinfo.qname);
                return;
        }
        q->w = w;
        /* process new query */
        if(!mesh_new_callback(w->env->mesh, &qinfo, qflags, &edns, 
                w->back->udp_buff, qid, libworker_bg_done_cb, q, 0)) {
                add_bg_result(w, q, NULL, UB_NOMEM, NULL, 0);
        }
        free(qinfo.qname);
}

void libworker_alloc_cleanup(void* arg)
{
        struct libworker* w = (struct libworker*)arg;
        slabhash_clear(&w->env->rrset_cache->table);
        slabhash_clear(w->env->msg_cache);
}

struct outbound_entry* libworker_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 libworker* w = (struct libworker*)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(w->back, qinfo, flags, dnssec,
                want_dnssec, nocaps, check_ratelimit, tcp_upstream, ssl_upstream,
                tls_auth_name, addr, addrlen, zone, zonelen, q,
                libworker_handle_service_reply, e, w->back->udp_buff, q->env,
                was_ratelimited);
        if(!e->qsent) {
                return NULL;
        }
        return e;
}

int 
libworker_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 libworker* lw = (struct libworker*)e->qstate->env->worker;

        if(error != 0) {
                mesh_report_reply(lw->env->mesh, e, reply_info, error);
                return 0;
        }
        /* sanity check. */
        if(!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. */
                mesh_report_reply(lw->env->mesh, e, reply_info, 
                        NETEVENT_TIMEOUT);
                return 0;
        }
        mesh_report_reply(lw->env->mesh,  e, reply_info, NETEVENT_NOERROR);
        return 0;
}

/* --- fake callbacks for fptr_wlist to work --- */
void worker_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);
}

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

int worker_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;
}

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

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

void worker_sighandler(int ATTR_UNUSED(sig), void* ATTR_UNUSED(arg))
{
        log_assert(0);
}

struct outbound_entry* worker_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;
}

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

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

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

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

void worker_stop_accept(void* ATTR_UNUSED(arg))
{
        log_assert(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;
}

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

void remote_get_opt_ssl(char* ATTR_UNUSED(str), void* ATTR_UNUSED(arg))
{
        log_assert(0);
}

#ifdef UB_ON_WINDOWS
void
worker_win_stop_cb(int ATTR_UNUSED(fd), short ATTR_UNUSED(ev), void* 
        ATTR_UNUSED(arg)) {
        log_assert(0);
}

void
wsvc_cron_cb(void* ATTR_UNUSED(arg))
{
        log_assert(0);
}
#endif /* UB_ON_WINDOWS */

#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

void fast_reload_service_cb(int ATTR_UNUSED(fd), short ATTR_UNUSED(ev),
        void* ATTR_UNUSED(arg))
{
        log_assert(0);
}

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

#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