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worker.c

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/*
 * 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 REGENTS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * \file
 *
 * This file 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/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/mesh.h"
#include "services/localzone.h"
#include "util/data/msgparse.h"
#include "util/data/msgencode.h"
#include "util/data/dname.h"
#include "util/fptr_wlist.h"

#ifdef HAVE_SYS_TYPES_H
#  include <sys/types.h>
#endif
#include <netdb.h>
#include <signal.h>

/** Size of an UDP datagram */
00074 #define NORMAL_UDP_SIZE 512 /* bytes */

#ifdef UNBOUND_ALLOC_STATS
/** measure memory leakage */
static void
debug_memleak(size_t accounted, size_t heap, 
      size_t total_alloc, size_t total_free)
{
      static int init = 0;
      static size_t base_heap, base_accounted, base_alloc, base_free;
      size_t base_af, cur_af, grow_af, grow_acc;
      if(!init) {
            init = 1;
            base_heap = heap;
            base_accounted = accounted;
            base_alloc = total_alloc;
            base_free = total_free;
      }
      base_af = base_alloc - base_free;
      cur_af = total_alloc - total_free;
      grow_af = cur_af - base_af;
      grow_acc = accounted - base_accounted;
      log_info("Leakage: %d leaked. growth: %u use, %u acc, %u heap",
            (int)(grow_af - grow_acc), (unsigned)grow_af, 
            (unsigned)grow_acc, (unsigned)(heap - base_heap));
}

/** give debug heap size indication */
static void
debug_total_mem(size_t calctotal)
{
      extern void* unbound_start_brk;
      extern size_t unbound_mem_alloc, unbound_mem_freed;
      void* cur = sbrk(0);
      int total = cur-unbound_start_brk;
      log_info("Total heap memory estimate: %u  total-alloc: %u  "
            "total-free: %u", (unsigned)total, 
            (unsigned)unbound_mem_alloc, (unsigned)unbound_mem_freed);
      debug_memleak(calctotal, (size_t)total, 
            unbound_mem_alloc, unbound_mem_freed);
}
#endif /* UNBOUND_ALLOC_STATS */

/** Report on memory usage by this thread and global */
void
00119 worker_mem_report(struct worker* ATTR_UNUSED(worker), 
      struct serviced_query* ATTR_UNUSED(cur_serv))
{
#ifdef UNBOUND_ALLOC_STATS
      /* debug func in validator module */
      size_t total, front, back, mesh, msg, rrset, infra, ac, superac;
      size_t me, iter, val;
      int i;
      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);
      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);
            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) 
            + ldns_buffer_capacity(worker->env.scratch_buffer);
      if(cur_serv) {
            me += serviced_get_mem(cur_serv);
      }
      total = front+back+mesh+msg+rrset+infra+iter+val+ac+superac+me;
      log_info("Memory conditions: %u front=%u back=%u mesh=%u msg=%u "
            "rrset=%u infra=%u iter=%u val=%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)ac, 
            (unsigned)superac, (unsigned)me);
      debug_total_mem(total);
#else /* no UNBOUND_ALLOC_STATS */
      size_t val = 0;
      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);
      }
      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 /* UNBOUND_ALLOC_STATS */
}

void 
00187 worker_send_cmd(struct worker* worker, ldns_buffer* buffer,
      enum worker_commands cmd)
{
      ldns_buffer_clear(buffer);
      /* like DNS message, length data */
      ldns_buffer_write_u16(buffer, sizeof(uint32_t));
      ldns_buffer_write_u32(buffer, (uint32_t)cmd);
      ldns_buffer_flip(buffer);
      if(!write_socket(worker->cmd_send_fd, ldns_buffer_begin(buffer),
            ldns_buffer_limit(buffer)))
            log_err("write socket: %s", strerror(errno));
}

int 
00201 worker_handle_reply(struct comm_point* c, void* arg, int error, 
      struct comm_reply* reply_info)
{
      struct module_qstate* q = (struct module_qstate*)arg;
      struct worker* worker = q->env->worker;
      struct outbound_entry e;
      e.qstate = q;
      e.qsent = NULL;

      if(error != 0) {
            mesh_report_reply(worker->env.mesh, &e, 0, reply_info);
            worker_mem_report(worker, NULL);
            return 0;
      }
      /* sanity check. */
      if(!LDNS_QR_WIRE(ldns_buffer_begin(c->buffer))
            || LDNS_OPCODE_WIRE(ldns_buffer_begin(c->buffer)) != 
                  LDNS_PACKET_QUERY
            || LDNS_QDCOUNT(ldns_buffer_begin(c->buffer)) > 1) {
            /* error becomes timeout for the module as if this reply
             * never arrived. */
            mesh_report_reply(worker->env.mesh, &e, 0, reply_info);
            worker_mem_report(worker, NULL);
            return 0;
      }
      mesh_report_reply(worker->env.mesh, &e, 1, reply_info);
      worker_mem_report(worker, NULL);
      return 0;
}

int 
00232 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, 0, reply_info);
            worker_mem_report(worker, sq);
            return 0;
      }
      /* sanity check. */
      if(!LDNS_QR_WIRE(ldns_buffer_begin(c->buffer))
            || LDNS_OPCODE_WIRE(ldns_buffer_begin(c->buffer)) != 
                  LDNS_PACKET_QUERY
            || LDNS_QDCOUNT(ldns_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, 0, reply_info);
            worker_mem_report(worker, sq);
            return 0;
      }
      mesh_report_reply(worker->env.mesh, e, 1, reply_info);
      worker_mem_report(worker, sq);
      return 0;
}

/** check request sanity. Returns error code, 0 OK, or -1 discard. 
 * @param pkt: the wire packet to examine for sanity.
 * @param worker: parameters for checking.
*/
static int 
00267 worker_check_request(ldns_buffer* pkt, struct worker* worker)
{
      if(ldns_buffer_limit(pkt) < LDNS_HEADER_SIZE) {
            verbose(VERB_QUERY, "request too short, discarded");
            return -1;
      }
      if(ldns_buffer_limit(pkt) > NORMAL_UDP_SIZE && 
            worker->daemon->cfg->harden_large_queries) {
            verbose(VERB_QUERY, "request too large, discarded");
            return -1;
      }
      if(LDNS_QR_WIRE(ldns_buffer_begin(pkt))) {
            verbose(VERB_QUERY, "request has QR bit on, discarded");
            return -1;
      }
      if(LDNS_TC_WIRE(ldns_buffer_begin(pkt))) {
            LDNS_TC_CLR(ldns_buffer_begin(pkt));
            verbose(VERB_QUERY, "request bad, has TC bit on");
            return LDNS_RCODE_FORMERR;
      }
      if(LDNS_OPCODE_WIRE(ldns_buffer_begin(pkt)) != LDNS_PACKET_QUERY) {
            verbose(VERB_QUERY, "request unknown opcode %d", 
                  LDNS_OPCODE_WIRE(ldns_buffer_begin(pkt)));
            return LDNS_RCODE_NOTIMPL;
      }
      if(LDNS_QDCOUNT(ldns_buffer_begin(pkt)) != 1) {
            verbose(VERB_QUERY, "request wrong nr qd=%d", 
                  LDNS_QDCOUNT(ldns_buffer_begin(pkt)));
            return LDNS_RCODE_FORMERR;
      }
      if(LDNS_ANCOUNT(ldns_buffer_begin(pkt)) != 0) {
            verbose(VERB_QUERY, "request wrong nr an=%d", 
                  LDNS_ANCOUNT(ldns_buffer_begin(pkt)));
            return LDNS_RCODE_FORMERR;
      }
      if(LDNS_NSCOUNT(ldns_buffer_begin(pkt)) != 0) {
            verbose(VERB_QUERY, "request wrong nr ns=%d", 
                  LDNS_NSCOUNT(ldns_buffer_begin(pkt)));
            return LDNS_RCODE_FORMERR;
      }
      if(LDNS_ARCOUNT(ldns_buffer_begin(pkt)) > 1) {
            verbose(VERB_QUERY, "request wrong nr ar=%d", 
                  LDNS_ARCOUNT(ldns_buffer_begin(pkt)));
            return LDNS_RCODE_FORMERR;
      }
      return 0;
}

int 
worker_handle_control_cmd(struct comm_point* c, void* arg, int error, 
      struct comm_reply* ATTR_UNUSED(reply_info))
{
      struct worker* worker = (struct worker*)arg;
      enum worker_commands cmd;
      if(error != NETEVENT_NOERROR) {
            if(error == NETEVENT_CLOSED)
                  comm_base_exit(worker->base);
            else  log_info("control event: %d", error);
            return 0;
      }
      if(ldns_buffer_limit(c->buffer) != sizeof(uint32_t)) {
            fatal_exit("bad control msg length %d", 
                  (int)ldns_buffer_limit(c->buffer));
      }
      cmd = ldns_buffer_read_u32(c->buffer);
      switch(cmd) {
      case worker_cmd_quit:
            verbose(VERB_ALGO, "got control cmd quit");
            comm_base_exit(worker->base);
            break;
      default:
            log_err("bad command %d", (int)cmd);
            break;
      }
      return 0;
}

/** check if a delegation is secure */
static enum sec_status
00346 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
00372 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
00394 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;
      uint32_t timenow = *worker->env.now;
      int must_validate = !(flags&BIT_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);
      if(!dp) { /* no delegation, need to reprime */
            regional_free_all(worker->scratchpad);
            return 0;
      }
      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 */
                  regional_free_all(worker->scratchpad);
                  return 0;
            case sec_status_bogus:
                  /* 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;
                  error_encode(repinfo->c->buffer, LDNS_RCODE_SERVFAIL, 
                        &msg->qinfo, id, flags, edns);
                  regional_free_all(worker->scratchpad);
                  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;
      msg->rep->flags |= BIT_QR|BIT_RA;
      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)) {
            error_encode(repinfo->c->buffer, LDNS_RCODE_SERVFAIL, 
                  &msg->qinfo, id, flags, edns);
      }
      regional_free_all(worker->scratchpad);
      return 1;
}

/** check cname chain in cache reply */
static int
00471 check_cache_chain(struct reply_info* rep) {
      /* check only answer section rrs for matching cname chain.
       * the cache may return changed rdata, but owner names are untouched.*/
      size_t i;
      uint8_t* sname = rep->rrsets[0]->rk.dname;
      size_t snamelen = rep->rrsets[0]->rk.dname_len;
      for(i=0; i<rep->an_numrrsets; i++) {
            uint16_t t = ntohs(rep->rrsets[i]->rk.type);
            if(t == LDNS_RR_TYPE_DNAME)
                  continue; /* skip dnames; note TTL 0 not cached */
            /* verify that owner matches current sname */
            if(query_dname_compare(sname, rep->rrsets[i]->rk.dname) != 0){
                  /* cname chain broken */
                  return 0;
            }
            /* if this is a cname; move on */
            if(t == LDNS_RR_TYPE_CNAME) {
                  get_cname_target(rep->rrsets[i], &sname, &snamelen);
            }
      }
      return 1;
}

/** check security status in cache reply */
static int
00496 all_rrsets_secure(struct reply_info* rep) {
      size_t i;
      for(i=0; i<rep->rrset_count; i++) {
            if( ((struct packed_rrset_data*)rep->rrsets[i]->entry.data)
                  ->security != sec_status_secure )
                  return 0;
      }
      return 1;
}

/** answer query from the cache */
static int
00508 answer_from_cache(struct worker* worker, struct query_info* qinfo,
      struct reply_info* rep, uint16_t id, uint16_t flags, 
      struct comm_reply* repinfo, struct edns_data* edns)
{
      uint32_t timenow = *worker->env.now;
      uint16_t udpsize = edns->udp_size;
      int secure;
      int must_validate = !(flags&BIT_CD) && worker->env.need_to_validate;
      /* see if it is possible */
      if(rep->ttl <= timenow) {
            /* the rrsets may have been updated in the meantime.
             * we will refetch the message format from the
             * authoritative server 
             */
            return 0;
      }
      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(!check_cache_chain(rep)) {
                  /* cname chain invalid, redo iterator steps */
                  verbose(VERB_ALGO, "Cache reply: cname chain broken");
            bail_out:
                  rrset_array_unlock_touch(worker->env.rrset_cache, 
                        worker->scratchpad, rep->ref, rep->rrset_count);
                  regional_free_all(worker->scratchpad);
                  return 0;
            }
      }
      /* check security status of the cached answer */
      if( rep->security == sec_status_bogus && must_validate) {
            /* BAD cached */
            edns->edns_version = EDNS_ADVERTISED_VERSION;
            edns->udp_size = EDNS_ADVERTISED_SIZE;
            edns->ext_rcode = 0;
            edns->bits &= EDNS_DO;
            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);
            regional_free_all(worker->scratchpad);
            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(all_rrsets_secure(rep))
                  secure = 1;
            else  {
                  if(must_validate) {
                        verbose(VERB_ALGO, "Cache reply: secure entry"
                              " changed status");
                        goto bail_out; /* rrset changed, re-verify */
                  }
                  secure = 0;
            }
      } else      secure = 0;

      edns->edns_version = EDNS_ADVERTISED_VERSION;
      edns->udp_size = EDNS_ADVERTISED_SIZE;
      edns->ext_rcode = 0;
      edns->bits &= EDNS_DO;
      if(!reply_info_answer_encode(qinfo, rep, id, flags, 
            repinfo->c->buffer, timenow, 1, worker->scratchpad,
            udpsize, edns, (int)(edns->bits & EDNS_DO), secure)) {
            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);
      regional_free_all(worker->scratchpad);
      /* go and return this buffer to the client */
      return 1;
}

/**
 * Fill CH class answer into buffer. Keeps query.
 * @param pkt: buffer
 * @param str: string to put into text record (<255).
 * @param edns: edns reply information.
 */
static void
00597 chaos_replystr(ldns_buffer* pkt, const char* str, struct edns_data* edns)
{
      size_t len = strlen(str);
      unsigned int rd = LDNS_RD_WIRE(ldns_buffer_begin(pkt));
      unsigned int cd = LDNS_CD_WIRE(ldns_buffer_begin(pkt));
      if(len>255) len=255; /* cap size of TXT record */
      ldns_buffer_clear(pkt);
      ldns_buffer_skip(pkt, (ssize_t)sizeof(uint16_t)); /* skip id */
      ldns_buffer_write_u16(pkt, (uint16_t)(BIT_QR|BIT_RA));
      if(rd) LDNS_RD_SET(ldns_buffer_begin(pkt));
      if(cd) LDNS_CD_SET(ldns_buffer_begin(pkt));
      ldns_buffer_write_u16(pkt, 1); /* qdcount */
      ldns_buffer_write_u16(pkt, 1); /* ancount */
      ldns_buffer_write_u16(pkt, 0); /* nscount */
      ldns_buffer_write_u16(pkt, 0); /* arcount */
      (void)query_dname_len(pkt); /* skip qname */
      ldns_buffer_skip(pkt, (ssize_t)sizeof(uint16_t)); /* skip qtype */
      ldns_buffer_skip(pkt, (ssize_t)sizeof(uint16_t)); /* skip qclass */
      ldns_buffer_write_u16(pkt, 0xc00c); /* compr ptr to query */
      ldns_buffer_write_u16(pkt, LDNS_RR_TYPE_TXT);
      ldns_buffer_write_u16(pkt, LDNS_RR_CLASS_CH);
      ldns_buffer_write_u32(pkt, 0); /* TTL */
      ldns_buffer_write_u16(pkt, sizeof(uint8_t) + len);
      ldns_buffer_write_u8(pkt, len);
      ldns_buffer_write(pkt, str, len);
      ldns_buffer_flip(pkt);
      edns->edns_version = EDNS_ADVERTISED_VERSION;
      edns->udp_size = EDNS_ADVERTISED_SIZE;
      edns->bits &= EDNS_DO;
      attach_edns_record(pkt, edns);
}

/**
 * Answer CH class queries.
 * @param w: worker
 * @param qinfo: query info. Pointer into packet buffer.
 * @param edns: edns info from query.
 * @param pkt: packet buffer.
 * @return: true if a reply is to be sent.
 */
static int
00638 answer_chaos(struct worker* w, struct query_info* qinfo, 
      struct edns_data* edns, ldns_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_replystr(pkt, buf, edns);
                  } else      {
                        log_err("gethostname: %s", strerror(errno));
                        chaos_replystr(pkt, "no hostname", edns);
                  }
            }
            else  chaos_replystr(pkt, cfg->identity, edns);
            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_replystr(pkt, PACKAGE_STRING, edns);
            else  chaos_replystr(pkt, cfg->version, edns);
            return 1;
      }
      return 0;
}

int 
00680 worker_handle_request(struct comm_point* c, void* arg, int error,
      struct comm_reply* repinfo)
{
      struct worker* worker = (struct worker*)arg;
      int ret;
      hashvalue_t h;
      struct lruhash_entry* e;
      struct query_info qinfo;
      struct edns_data edns;
      enum acl_access acl;

      if(error != NETEVENT_NOERROR) {
            /* some bad tcp query DNS formats give these error calls */
            verbose(VERB_ALGO, "handle request called with err=%d", error);
            return 0;
      }
      acl = acl_list_lookup(worker->daemon->acl, &repinfo->addr, 
            repinfo->addrlen);
      if(acl == acl_deny) {
            comm_point_drop_reply(repinfo);
            return 0;
      } else if(acl == acl_refuse) {
            ldns_buffer_set_limit(c->buffer, LDNS_HEADER_SIZE);
            ldns_buffer_write_at(c->buffer, 4, 
                  (uint8_t*)"\0\0\0\0\0\0\0\0", 8);
            LDNS_QR_SET(ldns_buffer_begin(c->buffer));
            LDNS_RCODE_SET(ldns_buffer_begin(c->buffer), 
                  LDNS_RCODE_REFUSED);
            log_addr(VERB_ALGO, "refused query from",
                  &repinfo->addr, repinfo->addrlen);
            log_buf(VERB_ALGO, "refuse", c->buffer);
            return 1;
      }
      if((ret=worker_check_request(c->buffer, worker)) != 0) {
            verbose(VERB_ALGO, "worker check request: bad query.");
            if(ret != -1) {
                  LDNS_QR_SET(ldns_buffer_begin(c->buffer));
                  LDNS_RCODE_SET(ldns_buffer_begin(c->buffer), ret);
                  return 1;
            }
            comm_point_drop_reply(repinfo);
            return 0;
      }
      worker->stats.num_queries++;
      /* see if query is in the cache */
      if(!query_info_parse(&qinfo, c->buffer)) {
            verbose(VERB_ALGO, "worker parse request: formerror.");
            LDNS_QR_SET(ldns_buffer_begin(c->buffer));
            LDNS_RCODE_SET(ldns_buffer_begin(c->buffer), 
                  LDNS_RCODE_FORMERR);
            return 1;
      }
      if(qinfo.qtype == LDNS_RR_TYPE_AXFR || 
            qinfo.qtype == LDNS_RR_TYPE_IXFR) {
            verbose(VERB_ALGO, "worker request: refused zone transfer.");
            LDNS_QR_SET(ldns_buffer_begin(c->buffer));
            LDNS_RCODE_SET(ldns_buffer_begin(c->buffer), 
                  LDNS_RCODE_REFUSED);
            return 1;
      }
      if((ret=parse_edns_from_pkt(c->buffer, &edns)) != 0) {
            verbose(VERB_ALGO, "worker parse edns: formerror.");
            LDNS_QR_SET(ldns_buffer_begin(c->buffer));
            LDNS_RCODE_SET(ldns_buffer_begin(c->buffer), ret);
            return 1;
      }
      if(edns.edns_present && edns.edns_version != 0) {
            edns.ext_rcode = (uint8_t)(EDNS_RCODE_BADVERS>>4);
            edns.edns_version = EDNS_ADVERTISED_VERSION;
            edns.udp_size = EDNS_ADVERTISED_SIZE;
            edns.bits &= EDNS_DO;
            verbose(VERB_ALGO, "query with bad edns version.");
            error_encode(c->buffer, EDNS_RCODE_BADVERS&0xf, &qinfo,
                  *(uint16_t*)ldns_buffer_begin(c->buffer),
                  ldns_buffer_read_u16_at(c->buffer, 2), NULL);
            attach_edns_record(c->buffer, &edns);
            return 1;
      }
      if(edns.edns_present && 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);
            edns.udp_size = NORMAL_UDP_SIZE;
      }
      if(edns.edns_present && edns.udp_size < LDNS_HEADER_SIZE) {
            verbose(VERB_ALGO, "worker request: edns is too small.");
            LDNS_QR_SET(ldns_buffer_begin(c->buffer));
            LDNS_TC_SET(ldns_buffer_begin(c->buffer));
            LDNS_RCODE_SET(ldns_buffer_begin(c->buffer), 
                  LDNS_RCODE_SERVFAIL);
            ldns_buffer_set_position(c->buffer, LDNS_HEADER_SIZE);
            ldns_buffer_write_at(c->buffer, 4, 
                  (uint8_t*)"\0\0\0\0\0\0\0\0", 8);
            ldns_buffer_flip(c->buffer);
            return 1;
      }
      if(c->type != comm_udp)
            edns.udp_size = 65535; /* max size for TCP replies */
      if(qinfo.qclass == LDNS_RR_CLASS_CH && answer_chaos(worker, &qinfo,
            &edns, c->buffer)) {
            return 1;
      }
      if(local_zones_answer(worker->daemon->local_zones, &qinfo, &edns, 
            c->buffer, worker->scratchpad)) {
            return (ldns_buffer_limit(c->buffer) != 0);
      }
      h = query_info_hash(&qinfo);
      if((e=slabhash_lookup(worker->env.msg_cache, h, &qinfo, 0))) {
            /* answer from cache - we have acquired a readlock on it */
            if(answer_from_cache(worker, &qinfo, 
                  (struct reply_info*)e->data, 
                  *(uint16_t*)ldns_buffer_begin(c->buffer), 
                  ldns_buffer_read_u16_at(c->buffer, 2), repinfo, 
                  &edns)) {
                  lock_rw_unlock(&e->lock);
                  return 1;
            }
            verbose(VERB_ALGO, "answer from the cache failed");
            lock_rw_unlock(&e->lock);
      }
      if(!LDNS_RD_WIRE(ldns_buffer_begin(c->buffer))) {
            if(answer_norec_from_cache(worker, &qinfo,
                  *(uint16_t*)ldns_buffer_begin(c->buffer), 
                  ldns_buffer_read_u16_at(c->buffer, 2), repinfo, 
                  &edns)) {
                  return 1;
            }
            verbose(VERB_ALGO, "answer norec from cache -- "
                  "need to validate or not primed");
      }
      ldns_buffer_rewind(c->buffer);
      server_stats_querymiss(&worker->stats, worker);

      /* grab a work request structure for this new request */
      if(worker->env.mesh->all.count > worker->request_size) {
            verbose(VERB_ALGO, "Too many requests active. "
                  "dropping incoming query.");
            worker->stats.num_query_list_exceeded++;
            comm_point_drop_reply(repinfo);
            return 0;
      } else if(worker->env.mesh->num_reply_addrs>worker->request_size*16) {
            verbose(VERB_ALGO, "Too many requests queued. "
                  "dropping incoming query.");
            worker->stats.num_query_list_exceeded++;
            comm_point_drop_reply(repinfo);
            return 0;
      }
      mesh_new_client(worker->env.mesh, &qinfo, 
            ldns_buffer_read_u16_at(c->buffer, 2),
            &edns, repinfo, *(uint16_t*)ldns_buffer_begin(c->buffer));
      worker_mem_report(worker, NULL);
      return 0;
}

void 
00835 worker_sighandler(int sig, void* arg)
{
      /* note that log, print, syscalls here give race conditions. */
      /* we still print DETAIL logs, because this is extensive per message
       * logging anyway, and the operator may then have an interest
       * in the cause for unbound to exit */
      struct worker* worker = (struct worker*)arg;
      switch(sig) {
            case SIGHUP:
                  verbose(VERB_QUERY, "caught signal SIGHUP");
                  comm_base_exit(worker->base);
                  break;
            case SIGINT:
                  verbose(VERB_QUERY, "caught signal SIGINT");
                  worker->need_to_exit = 1;
                  comm_base_exit(worker->base);
                  break;
            case SIGQUIT:
                  verbose(VERB_QUERY, "caught signal SIGQUIT");
                  worker->need_to_exit = 1;
                  comm_base_exit(worker->base);
                  break;
            case SIGTERM:
                  verbose(VERB_QUERY, "caught signal SIGTERM");
                  worker->need_to_exit = 1;
                  comm_base_exit(worker->base);
                  break;
            default:
                  log_err("unknown signal: %d, ignored", sig);
                  break;
      }
}

/** restart statistics timer for worker, if enabled */
static void
00870 worker_restart_timer(struct worker* worker)
{
      if(worker->env.cfg->stat_interval > 0) {
            struct timeval tv;
            tv.tv_sec = worker->env.cfg->stat_interval;
            tv.tv_usec = 0;
            comm_timer_set(worker->stat_timer, &tv);
      }
}

00880 void worker_stat_timer_cb(void* arg)
{
      struct worker* worker = (struct worker*)arg;
      server_stats_log(&worker->stats, worker->thread_num);
      mesh_stats(worker->env.mesh, "mesh has");
      worker_mem_report(worker, NULL);
      if(!worker->daemon->cfg->stat_cumulative) {
            server_stats_init(&worker->stats);
            mesh_stats_clear(worker->env.mesh);
      }
      /* start next timer */
      worker_restart_timer(worker);
}

struct worker* 
00895 worker_create(struct daemon* daemon, int id, int* ports, int n)
{
      struct worker* worker = (struct worker*)calloc(1, 
            sizeof(struct worker));
      if(!worker) 
            return NULL;
      worker->numports = n;
      worker->ports = (int*)memdup(ports, sizeof(int)*n);
      if(!worker->ports) {
            free(worker);
            return NULL;
      }
      worker->daemon = daemon;
      worker->thread_num = id;
      worker->cmd_send_fd = -1;
      worker->cmd_recv_fd = -1;
      if(id != 0) {
            int sv[2];
            /* create socketpair to communicate with worker */
            if(socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == -1) {
                  free(worker);
                  log_err("socketpair: %s", strerror(errno));
                  return NULL;
            }
            if(!fd_set_nonblock(sv[0]) || !fd_set_nonblock(sv[1])) {
                  close(sv[0]);
                  close(sv[1]);
                  free(worker);
                  return NULL;
            }
            worker->cmd_send_fd = sv[0];
            worker->cmd_recv_fd = sv[1];
      }
      return worker;
}

int
00932 worker_init(struct worker* worker, struct config_file *cfg, 
      struct listen_port* ports, int do_sigs)
{
      unsigned int seed;
      worker->need_to_exit = 0;
      worker->base = comm_base_create();
      if(!worker->base) {
            log_err("could not create event handling base");
            worker_delete(worker);
            return 0;
      }
      if(do_sigs) {
            ub_thread_sig_unblock(SIGHUP);
            ub_thread_sig_unblock(SIGINT);
            ub_thread_sig_unblock(SIGQUIT);
            ub_thread_sig_unblock(SIGTERM);
#ifndef LIBEVENT_SIGNAL_PROBLEM
            worker->comsig = comm_signal_create(worker->base, 
                  worker_sighandler, worker);
            if(!worker->comsig || !comm_signal_bind(worker->comsig, SIGHUP)
                  || !comm_signal_bind(worker->comsig, SIGINT)
                  || !comm_signal_bind(worker->comsig, SIGTERM)
                  || !comm_signal_bind(worker->comsig, SIGQUIT)) {
                  log_err("could not create signal handlers");
                  worker_delete(worker);
                  return 0;
            }
#endif /* LIBEVENT_SIGNAL_PROBLEM */
      } else { /* !do_sigs */
            worker->comsig = 0;
      }
      seed = (unsigned int)time(NULL) ^ (unsigned int)getpid() ^
            (((unsigned int)worker->thread_num)<<17);
            /* shift thread_num so it does not match out pid bits */
      if(!(worker->rndstate = ub_initstate(seed, NULL))) {
            seed = 0;
            log_err("could not init random numbers.");
            worker_delete(worker);
            return 0;
      }
      seed = 0;
      worker->front = listen_create(worker->base, ports,
            cfg->msg_buffer_size, (int)cfg->incoming_num_tcp, 
            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, 
            worker->daemon->env->infra_cache, worker->rndstate,
            cfg->use_caps_bits_for_id, worker->ports, worker->numports);
      if(!worker->back) {
            log_err("could not create outgoing sockets");
            worker_delete(worker);
            return 0;
      }
      if(worker->thread_num != 0) {
            /* start listening to commands */
            if(!(worker->cmd_com=comm_point_create_local(worker->base, 
                  worker->cmd_recv_fd, cfg->msg_buffer_size, 
                  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;
      }
      worker->request_size = cfg->num_queries_per_thread;

      server_stats_init(&worker->stats);
      alloc_init(&worker->alloc, &worker->daemon->superalloc, 
            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);
      if(worker->thread_num == 0)
            log_set_time(worker->env.now);
      worker->env.worker = worker;
      worker->env.send_packet = &worker_send_packet;
      worker->env.send_query = &worker_send_query;
      worker->env.alloc = &worker->alloc;
      worker->env.rnd = worker->rndstate;
      worker->env.scratch = worker->scratchpad;
      worker->env.mesh = mesh_create(&worker->daemon->mods, &worker->env);
      worker->env.detach_subs = &mesh_detach_subs;
      worker->env.attach_sub = &mesh_attach_sub;
      worker->env.kill_sub = &mesh_state_delete;
      worker->env.detect_cycle = &mesh_detect_cycle;
      worker->env.scratch_buffer = ldns_buffer_new(cfg->msg_buffer_size);
      if(!worker->env.mesh || !worker->env.scratch_buffer) {
            worker_delete(worker);
            return 0;
      }
      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);
      }
      return 1;
}

void 
01053 worker_work(struct worker* worker)
{
      comm_base_dispatch(worker->base);
}

void 
01059 worker_delete(struct worker* worker)
{
      if(!worker) 
            return;
      if(worker->env.mesh && verbosity >= VERB_OPS) {
            server_stats_log(&worker->stats, worker->thread_num);
            mesh_stats(worker->env.mesh, "mesh has");
            worker_mem_report(worker, NULL);
      }
      mesh_delete(worker->env.mesh);
      ldns_buffer_free(worker->env.scratch_buffer);
      listen_delete(worker->front);
      outside_network_delete(worker->back);
      comm_signal_delete(worker->comsig);
      comm_point_delete(worker->cmd_com);
      comm_timer_delete(worker->stat_timer);
      free(worker->ports);
      if(worker->thread_num == 0)
            log_set_time(NULL);
      comm_base_delete(worker->base);
      ub_randfree(worker->rndstate);
      /* close fds after deleting commpoints, to be sure.
         Also epoll does not like closing fd before event_del */
      if(worker->cmd_send_fd != -1)
            close(worker->cmd_send_fd);
      worker->cmd_send_fd = -1;
      if(worker->cmd_recv_fd != -1)
            close(worker->cmd_recv_fd);
      worker->cmd_recv_fd = -1;
      alloc_clear(&worker->alloc);
      regional_destroy(worker->scratchpad);
      free(worker);
}

int 
01094 worker_send_packet(ldns_buffer* pkt, struct sockaddr_storage* addr,
        socklen_t addrlen, int timeout, struct module_qstate* q, int use_tcp)
{
      struct worker* worker = q->env->worker;
      if(use_tcp) {
            return pending_tcp_query(worker->back, pkt, addr, addrlen, 
                  timeout, worker_handle_reply, q) != 0;
      }
      return pending_udp_query(worker->back, pkt, addr, addrlen, 
            timeout*1000, worker_handle_reply, q) != 0;
}

/** compare outbound entry qstates */
static int
01108 outbound_entry_compare(void* a, void* b)
{
      struct outbound_entry* e1 = (struct outbound_entry*)a;
      struct outbound_entry* e2 = (struct outbound_entry*)b;
      if(e1->qstate == e2->qstate)
            return 1;
      return 0;
}

struct outbound_entry*
01118 worker_send_query(uint8_t* qname, size_t qnamelen, uint16_t qtype,
      uint16_t qclass, uint16_t flags, int dnssec,
      struct sockaddr_storage* addr, socklen_t addrlen,
      struct module_qstate* q)
{
      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, qname,
            qnamelen, qtype, qclass, flags, dnssec, addr, addrlen, 
            worker_handle_service_reply, e, worker->back->udp_buff,
            &outbound_entry_compare);
      if(!e->qsent) {
            return NULL;
      }
      return e;
}

void 
01140 worker_alloc_cleanup(void* arg)
{
      struct worker* worker = (struct worker*)arg;
      slabhash_clear(&worker->env.rrset_cache->table);
      slabhash_clear(worker->env.msg_cache);
}

/* --- fake callbacks for fptr_wlist to work --- */
int libworker_send_packet(ldns_buffer* ATTR_UNUSED(pkt), 
      struct sockaddr_storage* ATTR_UNUSED(addr), 
      socklen_t ATTR_UNUSED(addrlen), int ATTR_UNUSED(timeout), 
      struct module_qstate* ATTR_UNUSED(q), int ATTR_UNUSED(use_tcp))
{
      log_assert(0);
      return 0;
}

struct outbound_entry* libworker_send_query(uint8_t* ATTR_UNUSED(qname), 
      size_t ATTR_UNUSED(qnamelen), uint16_t ATTR_UNUSED(qtype), 
      uint16_t ATTR_UNUSED(qclass), uint16_t ATTR_UNUSED(flags), 
      int ATTR_UNUSED(dnssec), struct sockaddr_storage* ATTR_UNUSED(addr), 
      socklen_t ATTR_UNUSED(addrlen), struct module_qstate* ATTR_UNUSED(q))
{
      log_assert(0);
      return 0;
}

int libworker_handle_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 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;
}

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

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