/src/unbound/services/outside_network.c

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/*
 * services/outside_network.c - implement sending of queries and wait answer.
 *
 * 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 has functions to send queries to authoritative servers and
 * wait for the pending answer events.
 */
#include "config.h"
#include <ctype.h>
#ifdef HAVE_SYS_TYPES_H
#  include <sys/types.h>
#endif
#include <sys/time.h>
#include "services/outside_network.h"
#include "services/listen_dnsport.h"
#include "services/cache/infra.h"
#include "iterator/iterator.h"
#include "util/data/msgparse.h"
#include "util/data/msgreply.h"
#include "util/data/msgencode.h"
#include "util/data/dname.h"
#include "util/netevent.h"
#include "util/log.h"
#include "util/net_help.h"
#include "util/random.h"
#include "util/fptr_wlist.h"
#include "util/edns.h"
#include "sldns/sbuffer.h"
#include "dnstap/dnstap.h"
#ifdef HAVE_OPENSSL_SSL_H
#include <openssl/ssl.h>
#endif
#ifdef HAVE_X509_VERIFY_PARAM_SET1_HOST
#include <openssl/x509v3.h>
#endif

#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#include <fcntl.h>

/** number of times to retry making a random ID that is unique. */
#define MAX_ID_RETRY 1000
/** number of times to retry finding interface, port that can be opened. */
#define MAX_PORT_RETRY 10000
/** number of retries on outgoing UDP queries */
#define OUTBOUND_UDP_RETRY 1

/** initiate TCP transaction for serviced query */
static void serviced_tcp_initiate(struct serviced_query* sq, sldns_buffer* buff);
/** with a fd available, randomize and send UDP */
static int randomize_and_send_udp(struct pending* pend, sldns_buffer* packet,
  int timeout);

/** select a DNS ID for a TCP stream */
static uint16_t tcp_select_id(struct outside_network* outnet,
  struct reuse_tcp* reuse);

/** Perform serviced query UDP sending operation */
static int serviced_udp_send(struct serviced_query* sq, sldns_buffer* buff);

/** Send serviced query over TCP return false on initial failure */
static int serviced_tcp_send(struct serviced_query* sq, sldns_buffer* buff);

/** call the callbacks for a serviced query */
static void serviced_callbacks(struct serviced_query* sq, int error,
  struct comm_point* c, struct comm_reply* rep);

int 
pending_cmp(const void* key1, const void* key2)
{
  struct pending *p1 = (struct pending*)key1;
  struct pending *p2 = (struct pending*)key2;
  if(p1->id < p2->id)
    return -1;
  if(p1->id > p2->id)
    return 1;
  log_assert(p1->id == p2->id);
  return sockaddr_cmp(&p1->addr, p1->addrlen, &p2->addr, p2->addrlen);
}

int 
serviced_cmp(const void* key1, const void* key2)
{
  struct serviced_query* q1 = (struct serviced_query*)key1;
  struct serviced_query* q2 = (struct serviced_query*)key2;
  int r;
  if(q1->qbuflen < q2->qbuflen)
    return -1;
  if(q1->qbuflen > q2->qbuflen)
    return 1;
  log_assert(q1->qbuflen == q2->qbuflen);
  log_assert(q1->qbuflen >= 15 /* 10 header, root, type, class */);
  /* alternate casing of qname is still the same query */
  if((r = memcmp(q1->qbuf, q2->qbuf, 10)) != 0)
    return r;
  if((r = memcmp(q1->qbuf+q1->qbuflen-4, q2->qbuf+q2->qbuflen-4, 4)) != 0)
    return r;
  if(q1->dnssec != q2->dnssec) {
    if(q1->dnssec < q2->dnssec)
      return -1;
    return 1;
  }
  if((r = query_dname_compare(q1->qbuf+10, q2->qbuf+10)) != 0)
    return r;
  if((r = edns_opt_list_compare(q1->opt_list, q2->opt_list)) != 0)
    return r;
  return sockaddr_cmp(&q1->addr, q1->addrlen, &q2->addr, q2->addrlen);
}

/** compare if the reuse element has the same address, port and same ssl-is
 * used-for-it characteristic */
static int
reuse_cmp_addrportssl(const void* key1, const void* key2)
{
  struct reuse_tcp* r1 = (struct reuse_tcp*)key1;
  struct reuse_tcp* r2 = (struct reuse_tcp*)key2;
  int r;
  /* compare address and port */
  r = sockaddr_cmp(&r1->addr, r1->addrlen, &r2->addr, r2->addrlen);
  if(r != 0)
    return r;

  /* compare if SSL-enabled */
  if(r1->is_ssl && !r2->is_ssl)
    return 1;
  if(!r1->is_ssl && r2->is_ssl)
    return -1;
  return 0;
}

int
reuse_cmp(const void* key1, const void* key2)
{
  int r;
  r = reuse_cmp_addrportssl(key1, key2);
  if(r != 0)
    return r;

  /* compare ptr value */
  if(key1 < key2) return -1;
  if(key1 > key2) return 1;
  return 0;
}

int reuse_id_cmp(const void* key1, const void* key2)
{
  struct waiting_tcp* w1 = (struct waiting_tcp*)key1;
  struct waiting_tcp* w2 = (struct waiting_tcp*)key2;
  if(w1->id < w2->id)
    return -1;
  if(w1->id > w2->id)
    return 1;
  return 0;
}

/** delete waiting_tcp entry. Does not unlink from waiting list. 
 * @param w: to delete.
 */
static void
waiting_tcp_delete(struct waiting_tcp* w)
{
  if(!w) return;
  if(w->timer)
    comm_timer_delete(w->timer);
  free(w);
}

/** 
 * Pick random outgoing-interface of that family, and bind it.
 * port set to 0 so OS picks a port number for us.
 * if it is the ANY address, do not bind.
 * @param pend: pending tcp structure, for storing the local address choice.
 * @param w: tcp structure with destination address.
 * @param s: socket fd.
 * @return false on error, socket closed.
 */
static int
pick_outgoing_tcp(struct pending_tcp* pend, struct waiting_tcp* w, int s)
{
  struct port_if* pi = NULL;
  int num;
  pend->pi = NULL;
#ifdef INET6
  if(addr_is_ip6(&w->addr, w->addrlen))
    num = w->outnet->num_ip6;
  else
#endif
    num = w->outnet->num_ip4;
  if(num == 0) {
    log_err("no TCP outgoing interfaces of family");
    log_addr(VERB_OPS, "for addr", &w->addr, w->addrlen);
    sock_close(s);
    return 0;
  }
#ifdef INET6
  if(addr_is_ip6(&w->addr, w->addrlen))
    pi = &w->outnet->ip6_ifs[ub_random_max(w->outnet->rnd, num)];
  else
#endif
    pi = &w->outnet->ip4_ifs[ub_random_max(w->outnet->rnd, num)];
  log_assert(pi);
  pend->pi = pi;
  if(addr_is_any(&pi->addr, pi->addrlen)) {
    /* binding to the ANY interface is for listening sockets */
    return 1;
  }
  /* set port to 0 */
  if(addr_is_ip6(&pi->addr, pi->addrlen))
    ((struct sockaddr_in6*)&pi->addr)->sin6_port = 0;
  else  ((struct sockaddr_in*)&pi->addr)->sin_port = 0;
  if(bind(s, (struct sockaddr*)&pi->addr, pi->addrlen) != 0) {
#ifndef USE_WINSOCK
#ifdef EADDRNOTAVAIL
    if(!(verbosity < 4 && errno == EADDRNOTAVAIL))
#endif
#else /* USE_WINSOCK */
    if(!(verbosity < 4 && WSAGetLastError() == WSAEADDRNOTAVAIL))
#endif
        log_err("outgoing tcp: bind: %s", sock_strerror(errno));
    sock_close(s);
    return 0;
  }
  log_addr(VERB_ALGO, "tcp bound to src", &pi->addr, pi->addrlen);
  return 1;
}

/** get TCP file descriptor for address, returns -1 on failure,
 * tcp_mss is 0 or maxseg size to set for TCP packets. */
int
outnet_get_tcp_fd(struct sockaddr_storage* addr, socklen_t addrlen,
  int tcp_mss, int dscp, int nodelay)
{
  int s;
  int af;
  char* err;
#if defined(SO_REUSEADDR) || defined(IP_BIND_ADDRESS_NO_PORT) \
  || defined(TCP_NODELAY)
  int on = 1;
#endif
#ifdef INET6
  if(addr_is_ip6(addr, addrlen)){
    s = socket(PF_INET6, SOCK_STREAM, IPPROTO_TCP);
    af = AF_INET6;
  } else {
#else
  {
#endif
    af = AF_INET;
    s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  }
  if(s == -1) {
    log_err_addr("outgoing tcp: socket", sock_strerror(errno),
      addr, addrlen);
    return -1;
  }

#ifdef SO_REUSEADDR
  if(setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (void*)&on,
    (socklen_t)sizeof(on)) < 0) {
    verbose(VERB_ALGO, "outgoing tcp:"
      " setsockopt(.. SO_REUSEADDR ..) failed");
  }
#endif

  err = set_ip_dscp(s, af, dscp);
  if(err != NULL) {
    verbose(VERB_ALGO, "outgoing tcp:"
      "error setting IP DiffServ codepoint on socket");
  }

  if(tcp_mss > 0) {
#if defined(IPPROTO_TCP) && defined(TCP_MAXSEG)
    if(setsockopt(s, IPPROTO_TCP, TCP_MAXSEG,
      (void*)&tcp_mss, (socklen_t)sizeof(tcp_mss)) < 0) {
      verbose(VERB_ALGO, "outgoing tcp:"
        " setsockopt(.. TCP_MAXSEG ..) failed");
    }
#else
    verbose(VERB_ALGO, "outgoing tcp:"
      " setsockopt(TCP_MAXSEG) unsupported");
#endif /* defined(IPPROTO_TCP) && defined(TCP_MAXSEG) */
  }
#ifdef IP_BIND_ADDRESS_NO_PORT
  if(setsockopt(s, IPPROTO_IP, IP_BIND_ADDRESS_NO_PORT, (void*)&on,
    (socklen_t)sizeof(on)) < 0) {
    verbose(VERB_ALGO, "outgoing tcp:"
      " setsockopt(.. IP_BIND_ADDRESS_NO_PORT ..) failed");
  }
#endif /* IP_BIND_ADDRESS_NO_PORT */
  if(nodelay) {
#if defined(IPPROTO_TCP) && defined(TCP_NODELAY)
    if(setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (void*)&on,
      (socklen_t)sizeof(on)) < 0) {
      verbose(VERB_ALGO, "outgoing tcp:"
        " setsockopt(.. TCP_NODELAY ..) failed");
    }
#else
    verbose(VERB_ALGO, "outgoing tcp:"
      " setsockopt(.. TCP_NODELAY ..) unsupported");
#endif /* defined(IPPROTO_TCP) && defined(TCP_NODELAY) */
  }
  return s;
}

/** connect tcp connection to addr, 0 on failure */
int
outnet_tcp_connect(int s, struct sockaddr_storage* addr, socklen_t addrlen)
{
  if(connect(s, (struct sockaddr*)addr, addrlen) == -1) {
#ifndef USE_WINSOCK
#ifdef EINPROGRESS
    if(errno != EINPROGRESS) {
#endif
      if(tcp_connect_errno_needs_log(
        (struct sockaddr*)addr, addrlen))
        log_err_addr("outgoing tcp: connect",
          strerror(errno), addr, addrlen);
      close(s);
      return 0;
#ifdef EINPROGRESS
    }
#endif
#else /* USE_WINSOCK */
    if(WSAGetLastError() != WSAEINPROGRESS &&
      WSAGetLastError() != WSAEWOULDBLOCK) {
      closesocket(s);
      return 0;
    }
#endif
  }
  return 1;
}

/** log reuse item addr and ptr with message */
static void
log_reuse_tcp(enum verbosity_value v, const char* msg, struct reuse_tcp* reuse)
{
  uint16_t port;
  char addrbuf[128];
  if(verbosity < v) return;
  if(!reuse || !reuse->pending || !reuse->pending->c)
    return;
  addr_to_str(&reuse->addr, reuse->addrlen, addrbuf, sizeof(addrbuf));
  port = ntohs(((struct sockaddr_in*)&reuse->addr)->sin_port);
  verbose(v, "%s %s#%u fd %d", msg, addrbuf, (unsigned)port,
    reuse->pending->c->fd);
}

/** pop the first element from the writewait list */
struct waiting_tcp*
reuse_write_wait_pop(struct reuse_tcp* reuse)
{
  struct waiting_tcp* w = reuse->write_wait_first;
  if(!w)
    return NULL;
  log_assert(w->write_wait_queued);
  log_assert(!w->write_wait_prev);
  reuse->write_wait_first = w->write_wait_next;
  if(w->write_wait_next)
    w->write_wait_next->write_wait_prev = NULL;
  else  reuse->write_wait_last = NULL;
  w->write_wait_queued = 0;
  w->write_wait_next = NULL;
  w->write_wait_prev = NULL;
  return w;
}

/** remove the element from the writewait list */
void
reuse_write_wait_remove(struct reuse_tcp* reuse, struct waiting_tcp* w)
{
  log_assert(w);
  log_assert(w->write_wait_queued);
  if(!w)
    return;
  if(!w->write_wait_queued)
    return;
  if(w->write_wait_prev)
    w->write_wait_prev->write_wait_next = w->write_wait_next;
  else  reuse->write_wait_first = w->write_wait_next;
  log_assert(!w->write_wait_prev ||
    w->write_wait_prev->write_wait_next != w->write_wait_prev);
  if(w->write_wait_next)
    w->write_wait_next->write_wait_prev = w->write_wait_prev;
  else  reuse->write_wait_last = w->write_wait_prev;
  log_assert(!w->write_wait_next
    || w->write_wait_next->write_wait_prev != w->write_wait_next);
  w->write_wait_queued = 0;
  w->write_wait_next = NULL;
  w->write_wait_prev = NULL;
}

/** push the element after the last on the writewait list */
void
reuse_write_wait_push_back(struct reuse_tcp* reuse, struct waiting_tcp* w)
{
  if(!w) return;
  log_assert(!w->write_wait_queued);
  if(reuse->write_wait_last) {
    reuse->write_wait_last->write_wait_next = w;
    log_assert(reuse->write_wait_last->write_wait_next !=
      reuse->write_wait_last);
    w->write_wait_prev = reuse->write_wait_last;
  } else {
    reuse->write_wait_first = w;
    w->write_wait_prev = NULL;
  }
  w->write_wait_next = NULL;
  reuse->write_wait_last = w;
  w->write_wait_queued = 1;
}

/** insert element in tree by id */
void
reuse_tree_by_id_insert(struct reuse_tcp* reuse, struct waiting_tcp* w)
{
#ifdef UNBOUND_DEBUG
  rbnode_type* added;
#endif
  log_assert(w->id_node.key == NULL);
  w->id_node.key = w;
#ifdef UNBOUND_DEBUG
  added =
#else
  (void)
#endif
  rbtree_insert(&reuse->tree_by_id, &w->id_node);
  log_assert(added);  /* should have been added */
}

/** find element in tree by id */
struct waiting_tcp*
reuse_tcp_by_id_find(struct reuse_tcp* reuse, uint16_t id)
{
  struct waiting_tcp key_w;
  rbnode_type* n;
  memset(&key_w, 0, sizeof(key_w));
  key_w.id_node.key = &key_w;
  key_w.id = id;
  n = rbtree_search(&reuse->tree_by_id, &key_w);
  if(!n) return NULL;
  return (struct waiting_tcp*)n->key;
}

/** return ID value of rbnode in tree_by_id */
static uint16_t
tree_by_id_get_id(rbnode_type* node)
{
  struct waiting_tcp* w = (struct waiting_tcp*)node->key;
  return w->id;
}

/** insert into reuse tcp tree and LRU, false on failure (duplicate) */
int
reuse_tcp_insert(struct outside_network* outnet, struct pending_tcp* pend_tcp)
{
  log_reuse_tcp(VERB_CLIENT, "reuse_tcp_insert", &pend_tcp->reuse);
  if(pend_tcp->reuse.item_on_lru_list) {
    if(!pend_tcp->reuse.node.key)
      log_err("internal error: reuse_tcp_insert: "
        "in lru list without key");
    return 1;
  }
  pend_tcp->reuse.node.key = &pend_tcp->reuse;
  pend_tcp->reuse.pending = pend_tcp;
  if(!rbtree_insert(&outnet->tcp_reuse, &pend_tcp->reuse.node)) {
    /* We are not in the LRU list but we are already in the
     * tcp_reuse tree, strange.
     * Continue to add ourselves to the LRU list. */
    log_err("internal error: reuse_tcp_insert: in lru list but "
      "not in the tree");
  }
  /* insert into LRU, first is newest */
  pend_tcp->reuse.lru_prev = NULL;
  if(outnet->tcp_reuse_first) {
    pend_tcp->reuse.lru_next = outnet->tcp_reuse_first;
    log_assert(pend_tcp->reuse.lru_next != &pend_tcp->reuse);
    outnet->tcp_reuse_first->lru_prev = &pend_tcp->reuse;
    log_assert(outnet->tcp_reuse_first->lru_prev !=
      outnet->tcp_reuse_first);
  } else {
    pend_tcp->reuse.lru_next = NULL;
    outnet->tcp_reuse_last = &pend_tcp->reuse;
  }
  outnet->tcp_reuse_first = &pend_tcp->reuse;
  pend_tcp->reuse.item_on_lru_list = 1;
  log_assert((!outnet->tcp_reuse_first && !outnet->tcp_reuse_last) ||
    (outnet->tcp_reuse_first && outnet->tcp_reuse_last));
  log_assert(outnet->tcp_reuse_first != outnet->tcp_reuse_first->lru_next &&
    outnet->tcp_reuse_first != outnet->tcp_reuse_first->lru_prev);
  log_assert(outnet->tcp_reuse_last != outnet->tcp_reuse_last->lru_next &&
    outnet->tcp_reuse_last != outnet->tcp_reuse_last->lru_prev);
  return 1;
}

/** find reuse tcp stream to destination for query, or NULL if none */
static struct reuse_tcp*
reuse_tcp_find(struct outside_network* outnet, struct sockaddr_storage* addr,
  socklen_t addrlen, int use_ssl)
{
  struct waiting_tcp key_w;
  struct pending_tcp key_p;
  struct comm_point c;
  rbnode_type* result = NULL, *prev;
  verbose(VERB_CLIENT, "reuse_tcp_find");
  memset(&key_w, 0, sizeof(key_w));
  memset(&key_p, 0, sizeof(key_p));
  memset(&c, 0, sizeof(c));
  key_p.query = &key_w;
  key_p.c = &c;
  key_p.reuse.pending = &key_p;
  key_p.reuse.node.key = &key_p.reuse;
  if(use_ssl)
    key_p.reuse.is_ssl = 1;
  if(addrlen > (socklen_t)sizeof(key_p.reuse.addr))
    return NULL;
  memmove(&key_p.reuse.addr, addr, addrlen);
  key_p.reuse.addrlen = addrlen;

  verbose(VERB_CLIENT, "reuse_tcp_find: num reuse streams %u",
    (unsigned)outnet->tcp_reuse.count);
  if(outnet->tcp_reuse.root == NULL ||
    outnet->tcp_reuse.root == RBTREE_NULL)
    return NULL;
  if(rbtree_find_less_equal(&outnet->tcp_reuse, &key_p.reuse,
    &result)) {
    /* exact match */
    /* but the key is on stack, and ptr is compared, impossible */
    log_assert(&key_p.reuse != (struct reuse_tcp*)result);
    log_assert(&key_p != ((struct reuse_tcp*)result)->pending);
  }

  /* It is possible that we search for something before the first element
   * in the tree. Replace a null pointer with the first element.
   */
  if (!result) {
    verbose(VERB_CLIENT, "reuse_tcp_find: taking first");
    result = rbtree_first(&outnet->tcp_reuse);
  }

  /* not found, return null */
  if(!result || result == RBTREE_NULL)
    return NULL;

  /* It is possible that we got the previous address, but that the
   * address we are looking for is in the tree. If the address we got
   * is less than the address we are looking, then take the next entry.
   */
  if (reuse_cmp_addrportssl(result->key, &key_p.reuse) < 0) {
    verbose(VERB_CLIENT, "reuse_tcp_find: key too low");
    result = rbtree_next(result);
  }

  verbose(VERB_CLIENT, "reuse_tcp_find check inexact match");
  /* inexact match, find one of possibly several connections to the
   * same destination address, with the correct port, ssl, and
   * also less than max number of open queries, or else, fail to open
   * a new one */
  /* rewind to start of sequence of same address,port,ssl */
  prev = rbtree_previous(result);
  while(prev && prev != RBTREE_NULL &&
    reuse_cmp_addrportssl(prev->key, &key_p.reuse) == 0) {
    result = prev;
    prev = rbtree_previous(result);
  }

  /* loop to find first one that has correct characteristics */
  while(result && result != RBTREE_NULL &&
    reuse_cmp_addrportssl(result->key, &key_p.reuse) == 0) {
    if(((struct reuse_tcp*)result)->tree_by_id.count <
      outnet->max_reuse_tcp_queries) {
      /* same address, port, ssl-yes-or-no, and has
       * space for another query */
      return (struct reuse_tcp*)result;
    }
    result = rbtree_next(result);
  }
  return NULL;
}

/** use the buffer to setup writing the query */
static void
outnet_tcp_take_query_setup(int s, struct pending_tcp* pend,
  struct waiting_tcp* w)
{
  struct timeval tv;
  verbose(VERB_CLIENT, "outnet_tcp_take_query_setup: setup packet to write "
    "len %d timeout %d msec",
    (int)w->pkt_len, w->timeout);
  pend->c->tcp_write_pkt = w->pkt;
  pend->c->tcp_write_pkt_len = w->pkt_len;
  pend->c->tcp_write_and_read = 1;
  pend->c->tcp_write_byte_count = 0;
  pend->c->tcp_is_reading = 0;
  comm_point_start_listening(pend->c, s, -1);
  /* set timer on the waiting_tcp entry, this is the write timeout
   * for the written packet.  The timer on pend->c is the timer
   * for when there is no written packet and we have readtimeouts */
#ifndef S_SPLINT_S
  tv.tv_sec = w->timeout/1000;
  tv.tv_usec = (w->timeout%1000)*1000;
#endif
  /* if the waiting_tcp was previously waiting for a buffer in the
   * outside_network.tcpwaitlist, then the timer is reset now that
   * we start writing it */
  comm_timer_set(w->timer, &tv);
}

/** use next free buffer to service a tcp query */
static int
outnet_tcp_take_into_use(struct waiting_tcp* w)
{
  struct pending_tcp* pend = w->outnet->tcp_free;
  int s;
  log_assert(pend);
  log_assert(w->pkt);
  log_assert(w->pkt_len > 0);
  log_assert(w->addrlen > 0);
  pend->c->tcp_do_toggle_rw = 0;
  pend->c->tcp_do_close = 0;

  /* Consistency check, if we have ssl_upstream but no sslctx, then
   * log an error and return failure.
   */
  if (w->ssl_upstream && !w->outnet->sslctx) {
    log_err("SSL upstream requested but no SSL context");
    return 0;
  }

  /* open socket */
  s = outnet_get_tcp_fd(&w->addr, w->addrlen, w->outnet->tcp_mss,
    w->outnet->ip_dscp, w->ssl_upstream);

  if(s == -1)
    return 0;

  if(!pick_outgoing_tcp(pend, w, s))
    return 0;

  fd_set_nonblock(s);
#ifdef USE_OSX_MSG_FASTOPEN
  /* API for fast open is different here. We use a connectx() function and 
     then writes can happen as normal even using SSL.*/
  /* connectx requires that the len be set in the sockaddr struct*/
  struct sockaddr_in *addr_in = (struct sockaddr_in *)&w->addr;
  addr_in->sin_len = w->addrlen;
  sa_endpoints_t endpoints;
  endpoints.sae_srcif = 0;
  endpoints.sae_srcaddr = NULL;
  endpoints.sae_srcaddrlen = 0;
  endpoints.sae_dstaddr = (struct sockaddr *)&w->addr;
  endpoints.sae_dstaddrlen = w->addrlen;
  if (connectx(s, &endpoints, SAE_ASSOCID_ANY,  
               CONNECT_DATA_IDEMPOTENT | CONNECT_RESUME_ON_READ_WRITE,
               NULL, 0, NULL, NULL) == -1) {
    /* if fails, failover to connect for OSX 10.10 */
#ifdef EINPROGRESS
    if(errno != EINPROGRESS) {
#else
    if(1) {
#endif
      if(connect(s, (struct sockaddr*)&w->addr, w->addrlen) == -1) {
#else /* USE_OSX_MSG_FASTOPEN*/
#ifdef USE_MSG_FASTOPEN
  pend->c->tcp_do_fastopen = 1;
  /* Only do TFO for TCP in which case no connect() is required here.
     Don't combine client TFO with SSL, since OpenSSL can't 
     currently support doing a handshake on fd that already isn't connected*/
  if (w->outnet->sslctx && w->ssl_upstream) {
    if(connect(s, (struct sockaddr*)&w->addr, w->addrlen) == -1) {
#else /* USE_MSG_FASTOPEN*/
  if(connect(s, (struct sockaddr*)&w->addr, w->addrlen) == -1) {
#endif /* USE_MSG_FASTOPEN*/
#endif /* USE_OSX_MSG_FASTOPEN*/
#ifndef USE_WINSOCK
#ifdef EINPROGRESS
    if(errno != EINPROGRESS) {
#else
    if(1) {
#endif
      if(tcp_connect_errno_needs_log(
        (struct sockaddr*)&w->addr, w->addrlen))
        log_err_addr("outgoing tcp: connect",
          strerror(errno), &w->addr, w->addrlen);
      close(s);
#else /* USE_WINSOCK */
    if(WSAGetLastError() != WSAEINPROGRESS &&
      WSAGetLastError() != WSAEWOULDBLOCK) {
      closesocket(s);
#endif
      return 0;
    }
  }
#ifdef USE_MSG_FASTOPEN
  }
#endif /* USE_MSG_FASTOPEN */
#ifdef USE_OSX_MSG_FASTOPEN
    }
  }
#endif /* USE_OSX_MSG_FASTOPEN */
  if(w->outnet->sslctx && w->ssl_upstream) {
    pend->c->ssl = outgoing_ssl_fd(w->outnet->sslctx, s);
    if(!pend->c->ssl) {
      pend->c->fd = s;
      comm_point_close(pend->c);
      return 0;
    }
    verbose(VERB_ALGO, "the query is using TLS encryption, for %s",
      (w->tls_auth_name?w->tls_auth_name:"an unauthenticated connection"));
#ifdef USE_WINSOCK
    comm_point_tcp_win_bio_cb(pend->c, pend->c->ssl);
#endif
    pend->c->ssl_shake_state = comm_ssl_shake_write;
    if(!set_auth_name_on_ssl(pend->c->ssl, w->tls_auth_name,
      w->outnet->tls_use_sni)) {
      pend->c->fd = s;
#ifdef HAVE_SSL
      SSL_free(pend->c->ssl);
#endif
      pend->c->ssl = NULL;
      comm_point_close(pend->c);
      return 0;
    }
  }
  w->next_waiting = (void*)pend;
  w->outnet->num_tcp_outgoing++;
  w->outnet->tcp_free = pend->next_free;
  pend->next_free = NULL;
  pend->query = w;
  pend->reuse.outnet = w->outnet;
  pend->c->repinfo.remote_addrlen = w->addrlen;
  pend->c->tcp_more_read_again = &pend->reuse.cp_more_read_again;
  pend->c->tcp_more_write_again = &pend->reuse.cp_more_write_again;
  pend->reuse.cp_more_read_again = 0;
  pend->reuse.cp_more_write_again = 0;
  memcpy(&pend->c->repinfo.remote_addr, &w->addr, w->addrlen);
  pend->reuse.pending = pend;

  /* Remove from tree in case the is_ssl will be different and causes the
   * identity of the reuse_tcp to change; could result in nodes not being
   * deleted from the tree (because the new identity does not match the
   * previous node) but their ->key would be changed to NULL. */
  if(pend->reuse.node.key)
    reuse_tcp_remove_tree_list(w->outnet, &pend->reuse);

  if(pend->c->ssl)
    pend->reuse.is_ssl = 1;
  else  pend->reuse.is_ssl = 0;
  /* insert in reuse by address tree if not already inserted there */
  (void)reuse_tcp_insert(w->outnet, pend);
  reuse_tree_by_id_insert(&pend->reuse, w);
  outnet_tcp_take_query_setup(s, pend, w);
  return 1;
}

/** Touch the lru of a reuse_tcp element, it is in use.
 * This moves it to the front of the list, where it is not likely to
 * be closed.  Items at the back of the list are closed to make space. */
void
reuse_tcp_lru_touch(struct outside_network* outnet, struct reuse_tcp* reuse)
{
  if(!reuse->item_on_lru_list) {
    log_err("internal error: we need to touch the lru_list but item not in list");
    return; /* not on the list, no lru to modify */
  }
  log_assert(reuse->lru_prev ||
    (!reuse->lru_prev && outnet->tcp_reuse_first == reuse));
  if(!reuse->lru_prev)
    return; /* already first in the list */
  /* remove at current position */
  /* since it is not first, there is a previous element */
  reuse->lru_prev->lru_next = reuse->lru_next;
  log_assert(reuse->lru_prev->lru_next != reuse->lru_prev);
  if(reuse->lru_next)
    reuse->lru_next->lru_prev = reuse->lru_prev;
  else  outnet->tcp_reuse_last = reuse->lru_prev;
  log_assert(!reuse->lru_next || reuse->lru_next->lru_prev != reuse->lru_next);
  log_assert(outnet->tcp_reuse_last != outnet->tcp_reuse_last->lru_next &&
    outnet->tcp_reuse_last != outnet->tcp_reuse_last->lru_prev);
  /* insert at the front */
  reuse->lru_prev = NULL;
  reuse->lru_next = outnet->tcp_reuse_first;
  if(outnet->tcp_reuse_first) {
    outnet->tcp_reuse_first->lru_prev = reuse;
  }
  log_assert(reuse->lru_next != reuse);
  /* since it is not first, it is not the only element and
   * lru_next is thus not NULL and thus reuse is now not the last in
   * the list, so outnet->tcp_reuse_last does not need to be modified */
  outnet->tcp_reuse_first = reuse;
  log_assert(outnet->tcp_reuse_first != outnet->tcp_reuse_first->lru_next &&
    outnet->tcp_reuse_first != outnet->tcp_reuse_first->lru_prev);
  log_assert((!outnet->tcp_reuse_first && !outnet->tcp_reuse_last) ||
    (outnet->tcp_reuse_first && outnet->tcp_reuse_last));
}

/** Snip the last reuse_tcp element off of the LRU list */
struct reuse_tcp*
reuse_tcp_lru_snip(struct outside_network* outnet)
{
  struct reuse_tcp* reuse = outnet->tcp_reuse_last;
  if(!reuse) return NULL;
  /* snip off of LRU */
  log_assert(reuse->lru_next == NULL);
  if(reuse->lru_prev) {
    outnet->tcp_reuse_last = reuse->lru_prev;
    reuse->lru_prev->lru_next = NULL;
  } else {
    outnet->tcp_reuse_last = NULL;
    outnet->tcp_reuse_first = NULL;
  }
  log_assert((!outnet->tcp_reuse_first && !outnet->tcp_reuse_last) ||
    (outnet->tcp_reuse_first && outnet->tcp_reuse_last));
  reuse->item_on_lru_list = 0;
  reuse->lru_next = NULL;
  reuse->lru_prev = NULL;
  return reuse;
}

/** remove waiting tcp from the outnet waiting list */
void
outnet_waiting_tcp_list_remove(struct outside_network* outnet, struct waiting_tcp* w)
{
  struct waiting_tcp* p = outnet->tcp_wait_first, *prev = NULL;
  w->on_tcp_waiting_list = 0;
  while(p) {
    if(p == w) {
      /* remove w */
      if(prev)
        prev->next_waiting = w->next_waiting;
      else  outnet->tcp_wait_first = w->next_waiting;
      if(outnet->tcp_wait_last == w)
        outnet->tcp_wait_last = prev;
      w->next_waiting = NULL;
      return;
    }
    prev = p;
    p = p->next_waiting;
  }
  /* outnet_waiting_tcp_list_remove is currently called only with items
   * that are already in the waiting list. */
  log_assert(0);
}

/** pop the first waiting tcp from the outnet waiting list */
struct waiting_tcp*
outnet_waiting_tcp_list_pop(struct outside_network* outnet)
{
  struct waiting_tcp* w = outnet->tcp_wait_first;
  if(!outnet->tcp_wait_first) return NULL;
  log_assert(w->on_tcp_waiting_list);
  outnet->tcp_wait_first = w->next_waiting;
  if(outnet->tcp_wait_last == w)
    outnet->tcp_wait_last = NULL;
  w->on_tcp_waiting_list = 0;
  w->next_waiting = NULL;
  return w;
}

/** add waiting_tcp element to the outnet tcp waiting list */
void
outnet_waiting_tcp_list_add(struct outside_network* outnet,
  struct waiting_tcp* w, int set_timer)
{
  struct timeval tv;
  log_assert(!w->on_tcp_waiting_list);
  if(w->on_tcp_waiting_list)
    return;
  w->next_waiting = NULL;
  if(outnet->tcp_wait_last)
    outnet->tcp_wait_last->next_waiting = w;
  else  outnet->tcp_wait_first = w;
  outnet->tcp_wait_last = w;
  w->on_tcp_waiting_list = 1;
  if(set_timer) {
#ifndef S_SPLINT_S
    tv.tv_sec = w->timeout/1000;
    tv.tv_usec = (w->timeout%1000)*1000;
#endif
    comm_timer_set(w->timer, &tv);
  }
}

/** add waiting_tcp element as first to the outnet tcp waiting list */
void
outnet_waiting_tcp_list_add_first(struct outside_network* outnet,
  struct waiting_tcp* w, int reset_timer)
{
  struct timeval tv;
  log_assert(!w->on_tcp_waiting_list);
  if(w->on_tcp_waiting_list)
    return;
  w->next_waiting = outnet->tcp_wait_first;
  log_assert(w->next_waiting != w);
  if(!outnet->tcp_wait_last)
    outnet->tcp_wait_last = w;
  outnet->tcp_wait_first = w;
  w->on_tcp_waiting_list = 1;
  if(reset_timer) {
#ifndef S_SPLINT_S
    tv.tv_sec = w->timeout/1000;
    tv.tv_usec = (w->timeout%1000)*1000;
#endif
    comm_timer_set(w->timer, &tv);
  }
  log_assert(
    (!outnet->tcp_reuse_first && !outnet->tcp_reuse_last) ||
    (outnet->tcp_reuse_first && outnet->tcp_reuse_last));
}

/** call callback on waiting_tcp, if not NULL */
static void
waiting_tcp_callback(struct waiting_tcp* w, struct comm_point* c, int error,
  struct comm_reply* reply_info)
{
  if(w && w->cb) {
    fptr_ok(fptr_whitelist_pending_tcp(w->cb));
    (void)(*w->cb)(c, w->cb_arg, error, reply_info);
  }
}

/** see if buffers can be used to service TCP queries */
static void
use_free_buffer(struct outside_network* outnet)
{
  struct waiting_tcp* w;
  while(outnet->tcp_wait_first && !outnet->want_to_quit) {
#ifdef USE_DNSTAP
    struct pending_tcp* pend_tcp = NULL;
#endif
    struct reuse_tcp* reuse = NULL;
    w = outnet_waiting_tcp_list_pop(outnet);
    log_assert(
      (!outnet->tcp_reuse_first && !outnet->tcp_reuse_last) ||
      (outnet->tcp_reuse_first && outnet->tcp_reuse_last));
    reuse = reuse_tcp_find(outnet, &w->addr, w->addrlen,
      w->ssl_upstream);
    /* re-select an ID when moving to a new TCP buffer */
    w->id = tcp_select_id(outnet, reuse);
    LDNS_ID_SET(w->pkt, w->id);
    if(reuse) {
      log_reuse_tcp(VERB_CLIENT, "use free buffer for waiting tcp: "
        "found reuse", reuse);
#ifdef USE_DNSTAP
      pend_tcp = reuse->pending;
#endif
      reuse_tcp_lru_touch(outnet, reuse);
      comm_timer_disable(w->timer);
      w->next_waiting = (void*)reuse->pending;
      reuse_tree_by_id_insert(reuse, w);
      if(reuse->pending->query) {
        /* on the write wait list */
        reuse_write_wait_push_back(reuse, w);
      } else {
        /* write straight away */
        /* stop the timer on read of the fd */
        comm_point_stop_listening(reuse->pending->c);
        reuse->pending->query = w;
        outnet_tcp_take_query_setup(
          reuse->pending->c->fd, reuse->pending,
          w);
      }
    } else if(outnet->tcp_free) {
      struct pending_tcp* pend = w->outnet->tcp_free;
      rbtree_init(&pend->reuse.tree_by_id, reuse_id_cmp);
      pend->reuse.pending = pend;
      memcpy(&pend->reuse.addr, &w->addr, w->addrlen);
      pend->reuse.addrlen = w->addrlen;
      if(!outnet_tcp_take_into_use(w)) {
        waiting_tcp_callback(w, NULL, NETEVENT_CLOSED,
          NULL);
        waiting_tcp_delete(w);
#ifdef USE_DNSTAP
        w = NULL;
#endif
      }
#ifdef USE_DNSTAP
      pend_tcp = pend;
#endif
    } else {
      /* no reuse and no free buffer, put back at the start */
      outnet_waiting_tcp_list_add_first(outnet, w, 0);
      break;
    }
#ifdef USE_DNSTAP
    if(outnet->dtenv && pend_tcp && w && w->sq &&
      (outnet->dtenv->log_resolver_query_messages ||
      outnet->dtenv->log_forwarder_query_messages)) {
      sldns_buffer tmp;
      sldns_buffer_init_frm_data(&tmp, w->pkt, w->pkt_len);
      dt_msg_send_outside_query(outnet->dtenv, &w->sq->addr,
        &pend_tcp->pi->addr, comm_tcp, NULL, w->sq->zone,
        w->sq->zonelen, &tmp);
    }
#endif
  }
}

/** delete element from tree by id */
static void
reuse_tree_by_id_delete(struct reuse_tcp* reuse, struct waiting_tcp* w)
{
#ifdef UNBOUND_DEBUG
  rbnode_type* rem;
#endif
  log_assert(w->id_node.key != NULL);
#ifdef UNBOUND_DEBUG
  rem =
#else
  (void)
#endif
  rbtree_delete(&reuse->tree_by_id, w);
  log_assert(rem);  /* should have been there */
  w->id_node.key = NULL;
}

/** move writewait list to go for another connection. */
static void
reuse_move_writewait_away(struct outside_network* outnet,
  struct pending_tcp* pend)
{
  /* the writewait list has not been written yet, so if the
   * stream was closed, they have not actually been failed, only
   * the queries written.  Other queries can get written to another
   * stream.  For upstreams that do not support multiple queries
   * and answers, the stream can get closed, and then the queries
   * can get written on a new socket */
  struct waiting_tcp* w;
  if(pend->query && pend->query->error_count == 0 &&
    pend->c->tcp_write_pkt == pend->query->pkt &&
    pend->c->tcp_write_pkt_len == pend->query->pkt_len) {
    /* since the current query is not written, it can also
     * move to a free buffer */
    if(verbosity >= VERB_CLIENT && pend->query->pkt_len > 12+2+2 &&
      LDNS_QDCOUNT(pend->query->pkt) > 0 &&
      dname_valid(pend->query->pkt+12, pend->query->pkt_len-12)) {
      char buf[LDNS_MAX_DOMAINLEN];
      dname_str(pend->query->pkt+12, buf);
      verbose(VERB_CLIENT, "reuse_move_writewait_away current %s %d bytes were written",
        buf, (int)pend->c->tcp_write_byte_count);
    }
    pend->c->tcp_write_pkt = NULL;
    pend->c->tcp_write_pkt_len = 0;
    pend->c->tcp_write_and_read = 0;
    pend->reuse.cp_more_read_again = 0;
    pend->reuse.cp_more_write_again = 0;
    pend->c->tcp_is_reading = 1;
    w = pend->query;
    pend->query = NULL;
    /* increase error count, so that if the next socket fails too
     * the server selection is run again with this query failed
     * and it can select a different server (if possible), or
     * fail the query */
    w->error_count ++;
    reuse_tree_by_id_delete(&pend->reuse, w);
    outnet_waiting_tcp_list_add(outnet, w, 1);
  }
  while((w = reuse_write_wait_pop(&pend->reuse)) != NULL) {
    if(verbosity >= VERB_CLIENT && w->pkt_len > 12+2+2 &&
      LDNS_QDCOUNT(w->pkt) > 0 &&
      dname_valid(w->pkt+12, w->pkt_len-12)) {
      char buf[LDNS_MAX_DOMAINLEN];
      dname_str(w->pkt+12, buf);
      verbose(VERB_CLIENT, "reuse_move_writewait_away item %s", buf);
    }
    reuse_tree_by_id_delete(&pend->reuse, w);
    outnet_waiting_tcp_list_add(outnet, w, 1);
  }
}

/** remove reused element from tree and lru list */
void
reuse_tcp_remove_tree_list(struct outside_network* outnet,
  struct reuse_tcp* reuse)
{
  verbose(VERB_CLIENT, "reuse_tcp_remove_tree_list");
  if(reuse->node.key) {
    /* delete it from reuse tree */
    if(!rbtree_delete(&outnet->tcp_reuse, reuse)) {
      /* should not be possible, it should be there */
      char buf[256];
      addr_to_str(&reuse->addr, reuse->addrlen, buf,
        sizeof(buf));
      log_err("reuse tcp delete: node not present, internal error, %s ssl %d lru %d", buf, reuse->is_ssl, reuse->item_on_lru_list);
    }
    reuse->node.key = NULL;
    /* defend against loops on broken tree by zeroing the
     * rbnode structure */
    memset(&reuse->node, 0, sizeof(reuse->node));
  }
  /* delete from reuse list */
  if(reuse->item_on_lru_list) {
    if(reuse->lru_prev) {
      /* assert that members of the lru list are waiting
       * and thus have a pending pointer to the struct */
      log_assert(reuse->lru_prev->pending);
      reuse->lru_prev->lru_next = reuse->lru_next;
      log_assert(reuse->lru_prev->lru_next != reuse->lru_prev);
    } else {
      log_assert(!reuse->lru_next || reuse->lru_next->pending);
      outnet->tcp_reuse_first = reuse->lru_next;
      log_assert(!outnet->tcp_reuse_first ||
        (outnet->tcp_reuse_first !=
         outnet->tcp_reuse_first->lru_next &&
         outnet->tcp_reuse_first !=
         outnet->tcp_reuse_first->lru_prev));
    }
    if(reuse->lru_next) {
      /* assert that members of the lru list are waiting
       * and thus have a pending pointer to the struct */
      log_assert(reuse->lru_next->pending);
      reuse->lru_next->lru_prev = reuse->lru_prev;
      log_assert(reuse->lru_next->lru_prev != reuse->lru_next);
    } else {
      log_assert(!reuse->lru_prev || reuse->lru_prev->pending);
      outnet->tcp_reuse_last = reuse->lru_prev;
      log_assert(!outnet->tcp_reuse_last ||
        (outnet->tcp_reuse_last !=
         outnet->tcp_reuse_last->lru_next &&
         outnet->tcp_reuse_last !=
         outnet->tcp_reuse_last->lru_prev));
    }
    log_assert((!outnet->tcp_reuse_first && !outnet->tcp_reuse_last) ||
      (outnet->tcp_reuse_first && outnet->tcp_reuse_last));
    reuse->item_on_lru_list = 0;
    reuse->lru_next = NULL;
    reuse->lru_prev = NULL;
  }
  reuse->pending = NULL;
}

/** helper function that deletes an element from the tree of readwait
 * elements in tcp reuse structure */
static void reuse_del_readwait_elem(rbnode_type* node, void* ATTR_UNUSED(arg))
{
  struct waiting_tcp* w = (struct waiting_tcp*)node->key;
  waiting_tcp_delete(w);
}

/** delete readwait waiting_tcp elements, deletes the elements in the list */
void reuse_del_readwait(rbtree_type* tree_by_id)
{
  if(tree_by_id->root == NULL ||
    tree_by_id->root == RBTREE_NULL)
    return;
  traverse_postorder(tree_by_id, &reuse_del_readwait_elem, NULL);
  rbtree_init(tree_by_id, reuse_id_cmp);
}

/** decommission a tcp buffer, closes commpoint and frees waiting_tcp entry */
static void
decommission_pending_tcp(struct outside_network* outnet, 
  struct pending_tcp* pend)
{
  verbose(VERB_CLIENT, "decommission_pending_tcp");
  /* A certain code path can lead here twice for the same pending_tcp
   * creating a loop in the free pending_tcp list. */
  if(outnet->tcp_free != pend) {
    pend->next_free = outnet->tcp_free;
    outnet->tcp_free = pend;
  }
  if(pend->reuse.node.key) {
    /* needs unlink from the reuse tree to get deleted */
    reuse_tcp_remove_tree_list(outnet, &pend->reuse);
  }
  /* free SSL structure after remove from outnet tcp reuse tree,
   * because the c->ssl null or not is used for sorting in the tree */
  if(pend->c->ssl) {
#ifdef HAVE_SSL
    SSL_shutdown(pend->c->ssl);
    SSL_free(pend->c->ssl);
    pend->c->ssl = NULL;
#endif
  }
  comm_point_close(pend->c);
  pend->reuse.cp_more_read_again = 0;
  pend->reuse.cp_more_write_again = 0;
  /* unlink the query and writewait list, it is part of the tree
   * nodes and is deleted */
  pend->query = NULL;
  pend->reuse.write_wait_first = NULL;
  pend->reuse.write_wait_last = NULL;
  reuse_del_readwait(&pend->reuse.tree_by_id);
}

/** perform failure callbacks for waiting queries in reuse read rbtree */
static void reuse_cb_readwait_for_failure(rbtree_type* tree_by_id, int err)
{
  rbnode_type* node;
  if(tree_by_id->root == NULL ||
    tree_by_id->root == RBTREE_NULL)
    return;
  node = rbtree_first(tree_by_id);
  while(node && node != RBTREE_NULL) {
    struct waiting_tcp* w = (struct waiting_tcp*)node->key;
    waiting_tcp_callback(w, NULL, err, NULL);
    node = rbtree_next(node);
  }
}

/** mark the entry for being in the cb_and_decommission stage */
static void mark_for_cb_and_decommission(rbnode_type* node,
  void* ATTR_UNUSED(arg))
{
  struct waiting_tcp* w = (struct waiting_tcp*)node->key;
  /* Mark the waiting_tcp to signal later code (serviced_delete) that
   * this item is part of the backed up tree_by_id and will be deleted
   * later. */
  w->in_cb_and_decommission = 1;
  /* Mark the serviced_query for deletion so that later code through
   * callbacks (iter_clear .. outnet_serviced_query_stop) won't
   * prematurely delete it. */
  if(w->cb)
    ((struct serviced_query*)w->cb_arg)->to_be_deleted = 1;
}

/** perform callbacks for failure and also decommission pending tcp.
 * the callbacks remove references in sq->pending to the waiting_tcp
 * members of the tree_by_id in the pending tcp.  The pending_tcp is
 * removed before the callbacks, so that the callbacks do not modify
 * the pending_tcp due to its reference in the outside_network reuse tree */
static void reuse_cb_and_decommission(struct outside_network* outnet,
  struct pending_tcp* pend, int error)
{
  rbtree_type store;
  store = pend->reuse.tree_by_id;
  pend->query = NULL;
  rbtree_init(&pend->reuse.tree_by_id, reuse_id_cmp);
  pend->reuse.write_wait_first = NULL;
  pend->reuse.write_wait_last = NULL;
  decommission_pending_tcp(outnet, pend);
  if(store.root != NULL && store.root != RBTREE_NULL) {
    traverse_postorder(&store, &mark_for_cb_and_decommission, NULL);
  }
  reuse_cb_readwait_for_failure(&store, error);
  reuse_del_readwait(&store);
}

/** set timeout on tcp fd and setup read event to catch incoming dns msgs */
static void
reuse_tcp_setup_timeout(struct pending_tcp* pend_tcp, int tcp_reuse_timeout)
{
  log_reuse_tcp(VERB_CLIENT, "reuse_tcp_setup_timeout", &pend_tcp->reuse);
  comm_point_start_listening(pend_tcp->c, -1, tcp_reuse_timeout);
}

/** set timeout on tcp fd and setup read event to catch incoming dns msgs */
static void
reuse_tcp_setup_read_and_timeout(struct pending_tcp* pend_tcp, int tcp_reuse_timeout)
{
  log_reuse_tcp(VERB_CLIENT, "reuse_tcp_setup_readtimeout", &pend_tcp->reuse);
  sldns_buffer_clear(pend_tcp->c->buffer);
  pend_tcp->c->tcp_is_reading = 1;
  pend_tcp->c->tcp_byte_count = 0;
  comm_point_stop_listening(pend_tcp->c);
  comm_point_start_listening(pend_tcp->c, -1, tcp_reuse_timeout);
}

int 
outnet_tcp_cb(struct comm_point* c, void* arg, int error,
  struct comm_reply *reply_info)
{
  struct pending_tcp* pend = (struct pending_tcp*)arg;
  struct outside_network* outnet = pend->reuse.outnet;
  struct waiting_tcp* w = NULL;
  log_assert(pend->reuse.item_on_lru_list && pend->reuse.node.key);
  verbose(VERB_ALGO, "outnettcp cb");
  if(error == NETEVENT_TIMEOUT) {
    if(pend->c->tcp_write_and_read) {
      verbose(VERB_QUERY, "outnettcp got tcp timeout "
        "for read, ignored because write underway");
      /* if we are writing, ignore readtimer, wait for write timer
       * or write is done */
      return 0;
    } else {
      verbose(VERB_QUERY, "outnettcp got tcp timeout %s",
        (pend->reuse.tree_by_id.count?"for reading pkt":
        "for keepalive for reuse"));
    }
    /* must be timeout for reading or keepalive reuse,
     * close it. */
    reuse_tcp_remove_tree_list(outnet, &pend->reuse);
  } else if(error == NETEVENT_PKT_WRITTEN) {
    /* the packet we want to write has been written. */
    verbose(VERB_ALGO, "outnet tcp pkt was written event");
    log_assert(c == pend->c);
    log_assert(pend->query->pkt == pend->c->tcp_write_pkt);
    log_assert(pend->query->pkt_len == pend->c->tcp_write_pkt_len);
    pend->c->tcp_write_pkt = NULL;
    pend->c->tcp_write_pkt_len = 0;
    /* the pend.query is already in tree_by_id */
    log_assert(pend->query->id_node.key);
    pend->query = NULL;
    /* setup to write next packet or setup read timeout */
    if(pend->reuse.write_wait_first) {
      verbose(VERB_ALGO, "outnet tcp setup next pkt");
      /* we can write it straight away perhaps, set flag
       * because this callback called after a tcp write
       * succeeded and likely more buffer space is available
       * and we can write some more. */
      pend->reuse.cp_more_write_again = 1;
      pend->query = reuse_write_wait_pop(&pend->reuse);
      comm_point_stop_listening(pend->c);
      outnet_tcp_take_query_setup(pend->c->fd, pend,
        pend->query);
    } else {
      verbose(VERB_ALGO, "outnet tcp writes done, wait");
      pend->c->tcp_write_and_read = 0;
      pend->reuse.cp_more_read_again = 0;
      pend->reuse.cp_more_write_again = 0;
      pend->c->tcp_is_reading = 1;
      comm_point_stop_listening(pend->c);
      reuse_tcp_setup_timeout(pend, outnet->tcp_reuse_timeout);
    }
    return 0;
  } else if(error != NETEVENT_NOERROR) {
    verbose(VERB_QUERY, "outnettcp got tcp error %d", error);
    reuse_move_writewait_away(outnet, pend);
    /* pass error below and exit */
  } else {
    /* check ID */
    if(sldns_buffer_limit(c->buffer) < sizeof(uint16_t)) {
      log_addr(VERB_QUERY, 
        "outnettcp: bad ID in reply, too short, from:",
        &pend->reuse.addr, pend->reuse.addrlen);
      error = NETEVENT_CLOSED;
    } else {
      uint16_t id = LDNS_ID_WIRE(sldns_buffer_begin(
        c->buffer));
      /* find the query the reply is for */
      w = reuse_tcp_by_id_find(&pend->reuse, id);
      /* Make sure that the reply we got is at least for a
       * sent query with the same ID; the waiting_tcp that
       * gets a reply is assumed to not be waiting to be
       * sent. */
      if(w && (w->on_tcp_waiting_list || w->write_wait_queued))
        w = NULL;
    }
  }
  if(error == NETEVENT_NOERROR && !w) {
    /* no struct waiting found in tree, no reply to call */
    log_addr(VERB_QUERY, "outnettcp: bad ID in reply, from:",
      &pend->reuse.addr, pend->reuse.addrlen);
    error = NETEVENT_CLOSED;
  }
  if(error == NETEVENT_NOERROR) {
    /* add to reuse tree so it can be reused, if not a failure.
     * This is possible if the state machine wants to make a tcp
     * query again to the same destination. */
    if(outnet->tcp_reuse.count < outnet->tcp_reuse_max) {
      (void)reuse_tcp_insert(outnet, pend);
    }
  }
  if(w) {
    log_assert(!w->on_tcp_waiting_list);
    log_assert(!w->write_wait_queued);
    reuse_tree_by_id_delete(&pend->reuse, w);
    verbose(VERB_CLIENT, "outnet tcp callback query err %d buflen %d",
      error, (int)sldns_buffer_limit(c->buffer));
    waiting_tcp_callback(w, c, error, reply_info);
    waiting_tcp_delete(w);
  }
  verbose(VERB_CLIENT, "outnet_tcp_cb reuse after cb");
  if(error == NETEVENT_NOERROR && pend->reuse.node.key) {
    verbose(VERB_CLIENT, "outnet_tcp_cb reuse after cb: keep it");
    /* it is in the reuse_tcp tree, with other queries, or
     * on the empty list. do not decommission it */
    /* if there are more outstanding queries, we could try to
     * read again, to see if it is on the input,
     * because this callback called after a successful read
     * and there could be more bytes to read on the input */
    if(pend->reuse.tree_by_id.count != 0)
      pend->reuse.cp_more_read_again = 1;
    reuse_tcp_setup_read_and_timeout(pend, outnet->tcp_reuse_timeout);
    return 0;
  }
  verbose(VERB_CLIENT, "outnet_tcp_cb reuse after cb: decommission it");
  /* no queries on it, no space to keep it. or timeout or closed due
   * to error.  Close it */
  reuse_cb_and_decommission(outnet, pend, (error==NETEVENT_TIMEOUT?
    NETEVENT_TIMEOUT:NETEVENT_CLOSED));
  use_free_buffer(outnet);
  return 0;
}

/** lower use count on pc, see if it can be closed */
static void
portcomm_loweruse(struct outside_network* outnet, struct port_comm* pc)
{
  struct port_if* pif;
  pc->num_outstanding--;
  if(pc->num_outstanding > 0) {
    return;
  }
  /* close it and replace in unused list */
  verbose(VERB_ALGO, "close of port %d", pc->number);
  comm_point_close(pc->cp);
  pif = pc->pif;
  log_assert(pif->inuse > 0);
#ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
  pif->avail_ports[pif->avail_total - pif->inuse] = pc->number;
#endif
  pif->inuse--;
  pif->out[pc->index] = pif->out[pif->inuse];
  pif->out[pc->index]->index = pc->index;
  pc->next = outnet->unused_fds;
  outnet->unused_fds = pc;
}

/** try to send waiting UDP queries */
static void
outnet_send_wait_udp(struct outside_network* outnet)
{
  struct pending* pend;
  /* process waiting queries */
  while(outnet->udp_wait_first && outnet->unused_fds
    && !outnet->want_to_quit) {
    pend = outnet->udp_wait_first;
    outnet->udp_wait_first = pend->next_waiting;
    if(!pend->next_waiting) outnet->udp_wait_last = NULL;
    sldns_buffer_clear(outnet->udp_buff);
    sldns_buffer_write(outnet->udp_buff, pend->pkt, pend->pkt_len);
    sldns_buffer_flip(outnet->udp_buff);
    free(pend->pkt); /* freeing now makes get_mem correct */
    pend->pkt = NULL;
    pend->pkt_len = 0;
    log_assert(!pend->sq->busy);
    pend->sq->busy = 1;
    if(!randomize_and_send_udp(pend, outnet->udp_buff,
      pend->timeout)) {
      /* callback error on pending */
      if(pend->cb) {
        fptr_ok(fptr_whitelist_pending_udp(pend->cb));
        (void)(*pend->cb)(outnet->unused_fds->cp, pend->cb_arg, 
          NETEVENT_CLOSED, NULL);
      }
      pending_delete(outnet, pend);
    } else {
      pend->sq->busy = 0;
    }
  }
}

int 
outnet_udp_cb(struct comm_point* c, void* arg, int error,
  struct comm_reply *reply_info)
{
  struct outside_network* outnet = (struct outside_network*)arg;
  struct pending key;
  struct pending* p;
  verbose(VERB_ALGO, "answer cb");

  if(error != NETEVENT_NOERROR) {
    verbose(VERB_QUERY, "outnetudp got udp error %d", error);
    return 0;
  }
  if(sldns_buffer_limit(c->buffer) < LDNS_HEADER_SIZE) {
    verbose(VERB_QUERY, "outnetudp udp too short");
    return 0;
  }
  log_assert(reply_info);

  /* setup lookup key */
  key.id = (unsigned)LDNS_ID_WIRE(sldns_buffer_begin(c->buffer));
  memcpy(&key.addr, &reply_info->remote_addr, reply_info->remote_addrlen);
  key.addrlen = reply_info->remote_addrlen;
  verbose(VERB_ALGO, "Incoming reply id = %4.4x", key.id);
  log_addr(VERB_ALGO, "Incoming reply addr =", 
    &reply_info->remote_addr, reply_info->remote_addrlen);

  /* find it, see if this thing is a valid query response */
  verbose(VERB_ALGO, "lookup size is %d entries", (int)outnet->pending->count);
  p = (struct pending*)rbtree_search(outnet->pending, &key);
  if(!p) {
    verbose(VERB_QUERY, "received unwanted or unsolicited udp reply dropped.");
    log_buf(VERB_ALGO, "dropped message", c->buffer);
    outnet->unwanted_replies++;
    if(outnet->unwanted_threshold && ++outnet->unwanted_total 
      >= outnet->unwanted_threshold) {
      log_warn("unwanted reply total reached threshold (%u)"
        " you may be under attack."
        " defensive action: clearing the cache",
        (unsigned)outnet->unwanted_threshold);
      fptr_ok(fptr_whitelist_alloc_cleanup(
        outnet->unwanted_action));
      (*outnet->unwanted_action)(outnet->unwanted_param);
      outnet->unwanted_total = 0;
    }
    return 0;
  }

  verbose(VERB_ALGO, "received udp reply.");
  log_buf(VERB_ALGO, "udp message", c->buffer);
  if(p->pc->cp != c) {
    verbose(VERB_QUERY, "received reply id,addr on wrong port. "
      "dropped.");
    outnet->unwanted_replies++;
    if(outnet->unwanted_threshold && ++outnet->unwanted_total 
      >= outnet->unwanted_threshold) {
      log_warn("unwanted reply total reached threshold (%u)"
        " you may be under attack."
        " defensive action: clearing the cache",
        (unsigned)outnet->unwanted_threshold);
      fptr_ok(fptr_whitelist_alloc_cleanup(
        outnet->unwanted_action));
      (*outnet->unwanted_action)(outnet->unwanted_param);
      outnet->unwanted_total = 0;
    }
    return 0;
  }
  comm_timer_disable(p->timer);
  verbose(VERB_ALGO, "outnet handle udp reply");
  /* delete from tree first in case callback creates a retry */
  (void)rbtree_delete(outnet->pending, p->node.key);
  if(p->cb) {
    fptr_ok(fptr_whitelist_pending_udp(p->cb));
    (void)(*p->cb)(p->pc->cp, p->cb_arg, NETEVENT_NOERROR, reply_info);
  }
  portcomm_loweruse(outnet, p->pc);
  pending_delete(NULL, p);
  outnet_send_wait_udp(outnet);
  return 0;
}

/** calculate number of ip4 and ip6 interfaces*/
static void 
calc_num46(char** ifs, int num_ifs, int do_ip4, int do_ip6, 
  int* num_ip4, int* num_ip6)
{
  int i;
  *num_ip4 = 0;
  *num_ip6 = 0;
  if(num_ifs <= 0) {
    if(do_ip4)
      *num_ip4 = 1;
    if(do_ip6)
      *num_ip6 = 1;
    return;
  }
  for(i=0; i<num_ifs; i++)
  {
    if(str_is_ip6(ifs[i])) {
      if(do_ip6)
        (*num_ip6)++;
    } else {
      if(do_ip4)
        (*num_ip4)++;
    }
  }
}

void
pending_udp_timer_delay_cb(void* arg)
{
  struct pending* p = (struct pending*)arg;
  struct outside_network* outnet = p->outnet;
  verbose(VERB_ALGO, "timeout udp with delay");
  portcomm_loweruse(outnet, p->pc);
  pending_delete(outnet, p);
  outnet_send_wait_udp(outnet);
}

void 
pending_udp_timer_cb(void *arg)
{
  struct pending* p = (struct pending*)arg;
  struct outside_network* outnet = p->outnet;
  /* it timed out */
  verbose(VERB_ALGO, "timeout udp");
  if(p->cb) {
    fptr_ok(fptr_whitelist_pending_udp(p->cb));
    (void)(*p->cb)(p->pc->cp, p->cb_arg, NETEVENT_TIMEOUT, NULL);
  }
  /* if delayclose, keep port open for a longer time.
   * But if the udpwaitlist exists, then we are struggling to
   * keep up with demand for sockets, so do not wait, but service
   * the customer (customer service more important than portICMPs) */
  if(outnet->delayclose && !outnet->udp_wait_first) {
    p->cb = NULL;
    p->timer->callback = &pending_udp_timer_delay_cb;
    comm_timer_set(p->timer, &outnet->delay_tv);
    return;
  }
  portcomm_loweruse(outnet, p->pc);
  pending_delete(outnet, p);
  outnet_send_wait_udp(outnet);
}

/** create pending_tcp buffers */
static int
create_pending_tcp(struct outside_network* outnet, size_t bufsize)
{
  size_t i;
  if(outnet->num_tcp == 0)
    return 1; /* no tcp needed, nothing to do */
  if(!(outnet->tcp_conns = (struct pending_tcp **)calloc(
      outnet->num_tcp, sizeof(struct pending_tcp*))))
    return 0;
  for(i=0; i<outnet->num_tcp; i++) {
    if(!(outnet->tcp_conns[i] = (struct pending_tcp*)calloc(1, 
      sizeof(struct pending_tcp))))
      return 0;
    outnet->tcp_conns[i]->next_free = outnet->tcp_free;
    outnet->tcp_free = outnet->tcp_conns[i];
    outnet->tcp_conns[i]->c = comm_point_create_tcp_out(
      outnet->base, bufsize, outnet_tcp_cb, 
      outnet->tcp_conns[i]);
    if(!outnet->tcp_conns[i]->c)
      return 0;
  }
  return 1;
}

/** setup an outgoing interface, ready address */
static int setup_if(struct port_if* pif, const char* addrstr, 
  int* avail, int numavail, size_t numfd)
{
#ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
  pif->avail_total = numavail;
  pif->avail_ports = (int*)memdup(avail, (size_t)numavail*sizeof(int));
  if(!pif->avail_ports)
    return 0;
#endif
  if(!ipstrtoaddr(addrstr, UNBOUND_DNS_PORT, &pif->addr, &pif->addrlen) &&
     !netblockstrtoaddr(addrstr, UNBOUND_DNS_PORT,
            &pif->addr, &pif->addrlen, &pif->pfxlen))
    return 0;
  pif->maxout = (int)numfd;
  pif->inuse = 0;
  pif->out = (struct port_comm**)calloc(numfd, 
    sizeof(struct port_comm*));
  if(!pif->out)
    return 0;
  return 1;
}

struct outside_network* 
outside_network_create(struct comm_base *base, size_t bufsize, 
  size_t num_ports, char** ifs, int num_ifs, int do_ip4, 
  int do_ip6, size_t num_tcp, int dscp, struct infra_cache* infra,
  struct ub_randstate* rnd, int use_caps_for_id, int* availports, 
  int numavailports, size_t unwanted_threshold, int tcp_mss,
  void (*unwanted_action)(void*), void* unwanted_param, int do_udp,
  void* sslctx, int delayclose, int tls_use_sni, struct dt_env* dtenv,
  int udp_connect, int max_reuse_tcp_queries, int tcp_reuse_timeout,
  int tcp_auth_query_timeout)
{
  struct outside_network* outnet = (struct outside_network*)
    calloc(1, sizeof(struct outside_network));
  size_t k;
  if(!outnet) {
    log_err("malloc failed");
    return NULL;
  }
  comm_base_timept(base, &outnet->now_secs, &outnet->now_tv);
  outnet->base = base;
  outnet->num_tcp = num_tcp;
  outnet->max_reuse_tcp_queries = max_reuse_tcp_queries;
  outnet->tcp_reuse_timeout= tcp_reuse_timeout;
  outnet->tcp_auth_query_timeout = tcp_auth_query_timeout;
  outnet->num_tcp_outgoing = 0;
  outnet->num_udp_outgoing = 0;
  outnet->infra = infra;
  outnet->rnd = rnd;
  outnet->sslctx = sslctx;
  outnet->tls_use_sni = tls_use_sni;
#ifdef USE_DNSTAP
  outnet->dtenv = dtenv;
#else
  (void)dtenv;
#endif
  outnet->svcd_overhead = 0;
  outnet->want_to_quit = 0;
  outnet->unwanted_threshold = unwanted_threshold;
  outnet->unwanted_action = unwanted_action;
  outnet->unwanted_param = unwanted_param;
  outnet->use_caps_for_id = use_caps_for_id;
  outnet->do_udp = do_udp;
  outnet->tcp_mss = tcp_mss;
  outnet->ip_dscp = dscp;
#ifndef S_SPLINT_S
  if(delayclose) {
    outnet->delayclose = 1;
    outnet->delay_tv.tv_sec = delayclose/1000;
    outnet->delay_tv.tv_usec = (delayclose%1000)*1000;
  }
#endif
  if(udp_connect) {
    outnet->udp_connect = 1;
  }
  if(numavailports == 0 || num_ports == 0) {
    log_err("no outgoing ports available");
    outside_network_delete(outnet);
    return NULL;
  }
#ifndef INET6
  do_ip6 = 0;
#endif
  calc_num46(ifs, num_ifs, do_ip4, do_ip6, 
    &outnet->num_ip4, &outnet->num_ip6);
  if(outnet->num_ip4 != 0) {
    if(!(outnet->ip4_ifs = (struct port_if*)calloc(
      (size_t)outnet->num_ip4, sizeof(struct port_if)))) {
      log_err("malloc failed");
      outside_network_delete(outnet);
      return NULL;
    }
  }
  if(outnet->num_ip6 != 0) {
    if(!(outnet->ip6_ifs = (struct port_if*)calloc(
      (size_t)outnet->num_ip6, sizeof(struct port_if)))) {
      log_err("malloc failed");
      outside_network_delete(outnet);
      return NULL;
    }
  }
  if( !(outnet->udp_buff = sldns_buffer_new(bufsize)) ||
    !(outnet->pending = rbtree_create(pending_cmp)) ||
    !(outnet->serviced = rbtree_create(serviced_cmp)) ||
    !create_pending_tcp(outnet, bufsize)) {
    log_err("malloc failed");
    outside_network_delete(outnet);
    return NULL;
  }
  rbtree_init(&outnet->tcp_reuse, reuse_cmp);
  outnet->tcp_reuse_max = num_tcp;

  /* allocate commpoints */
  for(k=0; k<num_ports; k++) {
    struct port_comm* pc;
    pc = (struct port_comm*)calloc(1, sizeof(*pc));
    if(!pc) {
      log_err("malloc failed");
      outside_network_delete(outnet);
      return NULL;
    }
    pc->cp = comm_point_create_udp(outnet->base, -1, 
      outnet->udp_buff, 0, outnet_udp_cb, outnet, NULL);
    if(!pc->cp) {
      log_err("malloc failed");
      free(pc);
      outside_network_delete(outnet);
      return NULL;
    }
    pc->next = outnet->unused_fds;
    outnet->unused_fds = pc;
  }

  /* allocate interfaces */
  if(num_ifs == 0) {
    if(do_ip4 && !setup_if(&outnet->ip4_ifs[0], "0.0.0.0", 
      availports, numavailports, num_ports)) {
      log_err("malloc failed");
      outside_network_delete(outnet);
      return NULL;
    }
    if(do_ip6 && !setup_if(&outnet->ip6_ifs[0], "::", 
      availports, numavailports, num_ports)) {
      log_err("malloc failed");
      outside_network_delete(outnet);
      return NULL;
    }
  } else {
    size_t done_4 = 0, done_6 = 0;
    int i;
    for(i=0; i<num_ifs; i++) {
      if(str_is_ip6(ifs[i]) && do_ip6) {
        if(!setup_if(&outnet->ip6_ifs[done_6], ifs[i],
          availports, numavailports, num_ports)){
          log_err("malloc failed");
          outside_network_delete(outnet);
          return NULL;
        }
        done_6++;
      }
      if(!str_is_ip6(ifs[i]) && do_ip4) {
        if(!setup_if(&outnet->ip4_ifs[done_4], ifs[i],
          availports, numavailports, num_ports)){
          log_err("malloc failed");
          outside_network_delete(outnet);
          return NULL;
        }
        done_4++;
      }
    }
  }
  return outnet;
}

/** helper pending delete */
static void
pending_node_del(rbnode_type* node, void* arg)
{
  struct pending* pend = (struct pending*)node;
  struct outside_network* outnet = (struct outside_network*)arg;
  pending_delete(outnet, pend);
}

/** helper serviced delete */
static void
serviced_node_del(rbnode_type* node, void* ATTR_UNUSED(arg))
{
  struct serviced_query* sq = (struct serviced_query*)node;
  alloc_reg_release(sq->alloc, sq->region);
  if(sq->timer)
    comm_timer_delete(sq->timer);
  free(sq);
}

void 
outside_network_quit_prepare(struct outside_network* outnet)
{
  if(!outnet)
    return;
  /* prevent queued items from being sent */
  outnet->want_to_quit = 1; 
}

void 
outside_network_delete(struct outside_network* outnet)
{
  if(!outnet)
    return;
  outnet->want_to_quit = 1;
  /* check every element, since we can be called on malloc error */
  if(outnet->pending) {
    /* free pending elements, but do no unlink from tree. */
    traverse_postorder(outnet->pending, pending_node_del, NULL);
    free(outnet->pending);
  }
  if(outnet->serviced) {
    traverse_postorder(outnet->serviced, serviced_node_del, NULL);
    free(outnet->serviced);
  }
  if(outnet->udp_buff)
    sldns_buffer_free(outnet->udp_buff);
  if(outnet->unused_fds) {
    struct port_comm* p = outnet->unused_fds, *np;
    while(p) {
      np = p->next;
      comm_point_delete(p->cp);
      free(p);
      p = np;
    }
    outnet->unused_fds = NULL;
  }
  if(outnet->ip4_ifs) {
    int i, k;
    for(i=0; i<outnet->num_ip4; i++) {
      for(k=0; k<outnet->ip4_ifs[i].inuse; k++) {
        struct port_comm* pc = outnet->ip4_ifs[i].
          out[k];
        comm_point_delete(pc->cp);
        free(pc);
      }
#ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
      free(outnet->ip4_ifs[i].avail_ports);
#endif
      free(outnet->ip4_ifs[i].out);
    }
    free(outnet->ip4_ifs);
  }
  if(outnet->ip6_ifs) {
    int i, k;
    for(i=0; i<outnet->num_ip6; i++) {
      for(k=0; k<outnet->ip6_ifs[i].inuse; k++) {
        struct port_comm* pc = outnet->ip6_ifs[i].
          out[k];
        comm_point_delete(pc->cp);
        free(pc);
      }
#ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
      free(outnet->ip6_ifs[i].avail_ports);
#endif
      free(outnet->ip6_ifs[i].out);
    }
    free(outnet->ip6_ifs);
  }
  if(outnet->tcp_conns) {
    size_t i;
    for(i=0; i<outnet->num_tcp; i++)
      if(outnet->tcp_conns[i]) {
        struct pending_tcp* pend;
        pend = outnet->tcp_conns[i];
        if(pend->reuse.item_on_lru_list) {
          /* delete waiting_tcp elements that
           * the tcp conn is working on */
          decommission_pending_tcp(outnet, pend);
        }
        comm_point_delete(outnet->tcp_conns[i]->c);
        free(outnet->tcp_conns[i]);
        outnet->tcp_conns[i] = NULL;
      }
    free(outnet->tcp_conns);
    outnet->tcp_conns = NULL;
  }
  if(outnet->tcp_wait_first) {
    struct waiting_tcp* p = outnet->tcp_wait_first, *np;
    while(p) {
      np = p->next_waiting;
      waiting_tcp_delete(p);
      p = np;
    }
  }
  /* was allocated in struct pending that was deleted above */
  rbtree_init(&outnet->tcp_reuse, reuse_cmp);
  outnet->tcp_reuse_first = NULL;
  outnet->tcp_reuse_last = NULL;
  if(outnet->udp_wait_first) {
    struct pending* p = outnet->udp_wait_first, *np;
    while(p) {
      np = p->next_waiting;
      pending_delete(NULL, p);
      p = np;
    }
  }
  free(outnet);
}

void 
pending_delete(struct outside_network* outnet, struct pending* p)
{
  if(!p)
    return;
  if(outnet && outnet->udp_wait_first &&
    (p->next_waiting || p == outnet->udp_wait_last) ) {
    /* delete from waiting list, if it is in the waiting list */
    struct pending* prev = NULL, *x = outnet->udp_wait_first;
    while(x && x != p) {
      prev = x;
      x = x->next_waiting;
    }
    if(x) {
      log_assert(x == p);
      if(prev)
        prev->next_waiting = p->next_waiting;
      else  outnet->udp_wait_first = p->next_waiting;
      if(outnet->udp_wait_last == p)
        outnet->udp_wait_last = prev;
    }
  }
  if(outnet) {
    (void)rbtree_delete(outnet->pending, p->node.key);
  }
  if(p->timer)
    comm_timer_delete(p->timer);
  free(p->pkt);
  free(p);
}

static void
sai6_putrandom(struct sockaddr_in6 *sa, int pfxlen, struct ub_randstate *rnd)
{
  int i, last;
  if(!(pfxlen > 0 && pfxlen < 128))
    return;
  for(i = 0; i < (128 - pfxlen) / 8; i++) {
    sa->sin6_addr.s6_addr[15-i] = (uint8_t)ub_random_max(rnd, 256);
  }
  last = pfxlen & 7;
  if(last != 0) {
    sa->sin6_addr.s6_addr[15-i] |=
      ((0xFF >> last) & ub_random_max(rnd, 256));
  }
}

/**
 * Try to open a UDP socket for outgoing communication.
 * Sets sockets options as needed.
 * @param addr: socket address.
 * @param addrlen: length of address.
 * @param pfxlen: length of network prefix (for address randomisation).
 * @param port: port override for addr.
 * @param inuse: if -1 is returned, this bool means the port was in use.
 * @param rnd: random state (for address randomisation).
 * @param dscp: DSCP to use.
 * @return fd or -1
 */
static int
udp_sockport(struct sockaddr_storage* addr, socklen_t addrlen, int pfxlen,
  int port, int* inuse, struct ub_randstate* rnd, int dscp)
{
  int fd, noproto;
  if(addr_is_ip6(addr, addrlen)) {
    int freebind = 0;
    struct sockaddr_in6 sa = *(struct sockaddr_in6*)addr;
    sa.sin6_port = (in_port_t)htons((uint16_t)port);
    sa.sin6_flowinfo = 0;
    sa.sin6_scope_id = 0;
    if(pfxlen != 0) {
      freebind = 1;
      sai6_putrandom(&sa, pfxlen, rnd);
    }
    fd = create_udp_sock(AF_INET6, SOCK_DGRAM, 
      (struct sockaddr*)&sa, addrlen, 1, inuse, &noproto,
      0, 0, 0, NULL, 0, freebind, 0, dscp);
  } else {
    struct sockaddr_in* sa = (struct sockaddr_in*)addr;
    sa->sin_port = (in_port_t)htons((uint16_t)port);
    fd = create_udp_sock(AF_INET, SOCK_DGRAM, 
      (struct sockaddr*)addr, addrlen, 1, inuse, &noproto,
      0, 0, 0, NULL, 0, 0, 0, dscp);
  }
  return fd;
}

/** Select random ID */
static int
select_id(struct outside_network* outnet, struct pending* pend,
  sldns_buffer* packet)
{
  int id_tries = 0;
  pend->id = GET_RANDOM_ID(outnet->rnd);
  LDNS_ID_SET(sldns_buffer_begin(packet), pend->id);

  /* insert in tree */
  pend->node.key = pend;
  while(!rbtree_insert(outnet->pending, &pend->node)) {
    /* change ID to avoid collision */
    pend->id = GET_RANDOM_ID(outnet->rnd);
    LDNS_ID_SET(sldns_buffer_begin(packet), pend->id);
    id_tries++;
    if(id_tries == MAX_ID_RETRY) {
      pend->id=99999; /* non existent ID */
      log_err("failed to generate unique ID, drop msg");
      return 0;
    }
  }
  verbose(VERB_ALGO, "inserted new pending reply id=%4.4x", pend->id);
  return 1;
}

/** return true is UDP connect error needs to be logged */
static int udp_connect_needs_log(int err, struct sockaddr_storage* addr,
  socklen_t addrlen)
{
  switch(err) {
  case ECONNREFUSED:
#  ifdef ENETUNREACH
  case ENETUNREACH:
#  endif
#  ifdef EHOSTDOWN
  case EHOSTDOWN:
#  endif
#  ifdef EHOSTUNREACH
  case EHOSTUNREACH:
#  endif
#  ifdef ENETDOWN
  case ENETDOWN:
#  endif
#  ifdef EADDRNOTAVAIL
  case EADDRNOTAVAIL:
#  endif
  case EPERM:
  case EACCES:
    if(verbosity >= VERB_ALGO)
      return 1;
    return 0;
  case EINVAL:
    /* Stop 'Invalid argument for fe80::/10' addresses appearing
     * in the logs, at low verbosity. They cannot be sent to. */
    if(addr_is_ip6linklocal(addr, addrlen)) {
      if(verbosity >= VERB_ALGO)
        return 1;
      return 0;
    }
    break;
  default:
    break;
  }
  return 1;
}


/** Select random interface and port */
static int
select_ifport(struct outside_network* outnet, struct pending* pend,
  int num_if, struct port_if* ifs)
{
  int my_if, my_port, fd, portno, inuse, tries=0;
  struct port_if* pif;
  /* randomly select interface and port */
  if(num_if == 0) {
    verbose(VERB_QUERY, "Need to send query but have no "
      "outgoing interfaces of that family");
    return 0;
  }
  log_assert(outnet->unused_fds);
  tries = 0;
  while(1) {
    my_if = ub_random_max(outnet->rnd, num_if);
    pif = &ifs[my_if];
#ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
    if(outnet->udp_connect) {
      /* if we connect() we cannot reuse fds for a port */
      if(pif->inuse >= pif->avail_total) {
        tries++;
        if(tries < MAX_PORT_RETRY)
          continue;
        log_err("failed to find an open port, drop msg");
        return 0;
      }
      my_port = pif->inuse + ub_random_max(outnet->rnd,
        pif->avail_total - pif->inuse);
    } else  {
      my_port = ub_random_max(outnet->rnd, pif->avail_total);
      if(my_port < pif->inuse) {
        /* port already open */
        pend->pc = pif->out[my_port];
        verbose(VERB_ALGO, "using UDP if=%d port=%d",
          my_if, pend->pc->number);
        break;
      }
    }
    /* try to open new port, if fails, loop to try again */
    log_assert(pif->inuse < pif->maxout);
    portno = pif->avail_ports[my_port - pif->inuse];
#else
    my_port = portno = 0;
#endif
    fd = udp_sockport(&pif->addr, pif->addrlen, pif->pfxlen,
      portno, &inuse, outnet->rnd, outnet->ip_dscp);
    if(fd == -1 && !inuse) {
      /* nonrecoverable error making socket */
      return 0;
    }
    if(fd != -1) {
      verbose(VERB_ALGO, "opened UDP if=%d port=%d", 
        my_if, portno);
      if(outnet->udp_connect) {
        /* connect() to the destination */
        if(connect(fd, (struct sockaddr*)&pend->addr,
          pend->addrlen) < 0) {
          if(udp_connect_needs_log(errno,
            &pend->addr, pend->addrlen)) {
            log_err_addr("udp connect failed",
              strerror(errno), &pend->addr,
              pend->addrlen);
          }
          sock_close(fd);
          return 0;
        }
      }
      /* grab fd */
      pend->pc = outnet->unused_fds;
      outnet->unused_fds = pend->pc->next;

      /* setup portcomm */
      pend->pc->next = NULL;
      pend->pc->number = portno;
      pend->pc->pif = pif;
      pend->pc->index = pif->inuse;
      pend->pc->num_outstanding = 0;
      comm_point_start_listening(pend->pc->cp, fd, -1);

      /* grab port in interface */
      pif->out[pif->inuse] = pend->pc;
#ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
      pif->avail_ports[my_port - pif->inuse] =
        pif->avail_ports[pif->avail_total-pif->inuse-1];
#endif
      pif->inuse++;
      break;
    }
    /* failed, already in use */
    verbose(VERB_QUERY, "port %d in use, trying another", portno);
    tries++;
    if(tries == MAX_PORT_RETRY) {
      log_err("failed to find an open port, drop msg");
      return 0;
    }
  }
  log_assert(pend->pc);
  pend->pc->num_outstanding++;

  return 1;
}

static int
randomize_and_send_udp(struct pending* pend, sldns_buffer* packet, int timeout)
{
  struct timeval tv;
  struct outside_network* outnet = pend->sq->outnet;

  /* select id */
  if(!select_id(outnet, pend, packet)) {
    return 0;
  }

  /* select src_if, port */
  if(addr_is_ip6(&pend->addr, pend->addrlen)) {
    if(!select_ifport(outnet, pend, 
      outnet->num_ip6, outnet->ip6_ifs))
      return 0;
  } else {
    if(!select_ifport(outnet, pend, 
      outnet->num_ip4, outnet->ip4_ifs))
      return 0;
  }
  log_assert(pend->pc && pend->pc->cp);

  /* send it over the commlink */
  if(!comm_point_send_udp_msg(pend->pc->cp, packet,
    (struct sockaddr*)&pend->addr, pend->addrlen, outnet->udp_connect)) {
    portcomm_loweruse(outnet, pend->pc);
    return 0;
  }
  outnet->num_udp_outgoing++;

  /* system calls to set timeout after sending UDP to make roundtrip
     smaller. */
#ifndef S_SPLINT_S
  tv.tv_sec = timeout/1000;
  tv.tv_usec = (timeout%1000)*1000;
#endif
  comm_timer_set(pend->timer, &tv);

#ifdef USE_DNSTAP
  /*
   * sending src (local service)/dst (upstream) addresses over DNSTAP
   * There are no chances to get the src (local service) addr if unbound
   * is not configured with specific outgoing IP-addresses. So we will
   * pass 0.0.0.0 (::) to argument for
   * dt_msg_send_outside_query()/dt_msg_send_outside_response() calls.
   */
  if(outnet->dtenv &&
     (outnet->dtenv->log_resolver_query_messages ||
    outnet->dtenv->log_forwarder_query_messages)) {
      log_addr(VERB_ALGO, "from local addr", &pend->pc->pif->addr, pend->pc->pif->addrlen);
      log_addr(VERB_ALGO, "request to upstream", &pend->addr, pend->addrlen);
      dt_msg_send_outside_query(outnet->dtenv, &pend->addr, &pend->pc->pif->addr, comm_udp, NULL,
        pend->sq->zone, pend->sq->zonelen, packet);
  }
#endif
  return 1;
}

struct pending* 
pending_udp_query(struct serviced_query* sq, struct sldns_buffer* packet,
  int timeout, comm_point_callback_type* cb, void* cb_arg)
{
  struct pending* pend = (struct pending*)calloc(1, sizeof(*pend));
  if(!pend) return NULL;
  pend->outnet = sq->outnet;
  pend->sq = sq;
  pend->addrlen = sq->addrlen;
  memmove(&pend->addr, &sq->addr, sq->addrlen);
  pend->cb = cb;
  pend->cb_arg = cb_arg;
  pend->node.key = pend;
  pend->timer = comm_timer_create(sq->outnet->base, pending_udp_timer_cb,
    pend);
  if(!pend->timer) {
    free(pend);
    return NULL;
  }

  if(sq->outnet->unused_fds == NULL) {
    /* no unused fd, cannot create a new port (randomly) */
    verbose(VERB_ALGO, "no fds available, udp query waiting");
    pend->timeout = timeout;
    pend->pkt_len = sldns_buffer_limit(packet);
    pend->pkt = (uint8_t*)memdup(sldns_buffer_begin(packet),
      pend->pkt_len);
    if(!pend->pkt) {
      comm_timer_delete(pend->timer);
      free(pend);
      return NULL;
    }
    /* put at end of waiting list */
    if(sq->outnet->udp_wait_last)
      sq->outnet->udp_wait_last->next_waiting = pend;
    else 
      sq->outnet->udp_wait_first = pend;
    sq->outnet->udp_wait_last = pend;
    return pend;
  }
  log_assert(!sq->busy);
  sq->busy = 1;
  if(!randomize_and_send_udp(pend, packet, timeout)) {
    pending_delete(sq->outnet, pend);
    return NULL;
  }
  sq->busy = 0;
  return pend;
}

void
outnet_tcptimer(void* arg)
{
  struct waiting_tcp* w = (struct waiting_tcp*)arg;
  struct outside_network* outnet = w->outnet;
  verbose(VERB_CLIENT, "outnet_tcptimer");
  if(w->on_tcp_waiting_list) {
    /* it is on the waiting list */
    outnet_waiting_tcp_list_remove(outnet, w);
    waiting_tcp_callback(w, NULL, NETEVENT_TIMEOUT, NULL);
    waiting_tcp_delete(w);
  } else {
    /* it was in use */
    struct pending_tcp* pend=(struct pending_tcp*)w->next_waiting;
    reuse_cb_and_decommission(outnet, pend, NETEVENT_TIMEOUT);
  }
  use_free_buffer(outnet);
}

/** close the oldest reuse_tcp connection to make a fd and struct pend
 * available for a new stream connection */
static void
reuse_tcp_close_oldest(struct outside_network* outnet)
{
  struct reuse_tcp* reuse;
  verbose(VERB_CLIENT, "reuse_tcp_close_oldest");
  reuse = reuse_tcp_lru_snip(outnet);
  if(!reuse) return;
  /* free up */
  reuse_cb_and_decommission(outnet, reuse->pending, NETEVENT_CLOSED);
}

static uint16_t
tcp_select_id(struct outside_network* outnet, struct reuse_tcp* reuse)
{
  if(reuse)
    return reuse_tcp_select_id(reuse, outnet);
  return GET_RANDOM_ID(outnet->rnd);
}

/** find spare ID value for reuse tcp stream.  That is random and also does
 * not collide with an existing query ID that is in use or waiting */
uint16_t
reuse_tcp_select_id(struct reuse_tcp* reuse, struct outside_network* outnet)
{
  uint16_t id = 0, curid, nextid;
  const int try_random = 2000;
  int i;
  unsigned select, count, space;
  rbnode_type* node;

  /* make really sure the tree is not empty */
  if(reuse->tree_by_id.count == 0) {
    id = GET_RANDOM_ID(outnet->rnd);
    return id;
  }

  /* try to find random empty spots by picking them */
  for(i = 0; i<try_random; i++) {
    id = GET_RANDOM_ID(outnet->rnd);
    if(!reuse_tcp_by_id_find(reuse, id)) {
      return id;
    }
  }

  /* equally pick a random unused element from the tree that is
   * not in use.  Pick a the n-th index of an unused number,
   * then loop over the empty spaces in the tree and find it */
  log_assert(reuse->tree_by_id.count < 0xffff);
  select = ub_random_max(outnet->rnd, 0xffff - reuse->tree_by_id.count);
  /* select value now in 0 .. num free - 1 */

  count = 0; /* number of free spaces passed by */
  node = rbtree_first(&reuse->tree_by_id);
  log_assert(node && node != RBTREE_NULL); /* tree not empty */
  /* see if select is before first node */
  if(select < (unsigned)tree_by_id_get_id(node))
    return select;
  count += tree_by_id_get_id(node);
  /* perhaps select is between nodes */
  while(node && node != RBTREE_NULL) {
    rbnode_type* next = rbtree_next(node);
    if(next && next != RBTREE_NULL) {
      curid = tree_by_id_get_id(node);
      nextid = tree_by_id_get_id(next);
      log_assert(curid < nextid);
      if(curid != 0xffff && curid + 1 < nextid) {
        /* space between nodes */
        space = nextid - curid - 1;
        log_assert(select >= count);
        if(select < count + space) {
          /* here it is */
          return curid + 1 + (select - count);
        }
        count += space;
      }
    }
    node = next;
  }

  /* select is after the last node */
  /* count is the number of free positions before the nodes in the
   * tree */
  node = rbtree_last(&reuse->tree_by_id);
  log_assert(node && node != RBTREE_NULL); /* tree not empty */
  curid = tree_by_id_get_id(node);
  log_assert(count + (0xffff-curid) + reuse->tree_by_id.count == 0xffff);
  return curid + 1 + (select - count);
}

struct waiting_tcp*
pending_tcp_query(struct serviced_query* sq, sldns_buffer* packet,
  int timeout, comm_point_callback_type* callback, void* callback_arg)
{
  struct pending_tcp* pend = sq->outnet->tcp_free;
  struct reuse_tcp* reuse = NULL;
  struct waiting_tcp* w;

  verbose(VERB_CLIENT, "pending_tcp_query");
  if(sldns_buffer_limit(packet) < sizeof(uint16_t)) {
    verbose(VERB_ALGO, "pending tcp query with too short buffer < 2");
    return NULL;
  }

  /* find out if a reused stream to the target exists */
  /* if so, take it into use */
  reuse = reuse_tcp_find(sq->outnet, &sq->addr, sq->addrlen,
    sq->ssl_upstream);
  if(reuse) {
    log_reuse_tcp(VERB_CLIENT, "pending_tcp_query: found reuse", reuse);
    log_assert(reuse->pending);
    pend = reuse->pending;
    reuse_tcp_lru_touch(sq->outnet, reuse);
  }

  log_assert(!reuse || (reuse && pend));
  /* if !pend but we have reuse streams, close a reuse stream
   * to be able to open a new one to this target, no use waiting
   * to reuse a file descriptor while another query needs to use
   * that buffer and file descriptor now. */
  if(!pend) {
    reuse_tcp_close_oldest(sq->outnet);
    pend = sq->outnet->tcp_free;
    log_assert(!reuse || (pend == reuse->pending));
  }

  /* allocate space to store query */
  w = (struct waiting_tcp*)malloc(sizeof(struct waiting_tcp) 
    + sldns_buffer_limit(packet));
  if(!w) {
    return NULL;
  }
  if(!(w->timer = comm_timer_create(sq->outnet->base, outnet_tcptimer, w))) {
    free(w);
    return NULL;
  }
  w->pkt = (uint8_t*)w + sizeof(struct waiting_tcp);
  w->pkt_len = sldns_buffer_limit(packet);
  memmove(w->pkt, sldns_buffer_begin(packet), w->pkt_len);
  w->id = tcp_select_id(sq->outnet, reuse);
  LDNS_ID_SET(w->pkt, w->id);
  memcpy(&w->addr, &sq->addr, sq->addrlen);
  w->addrlen = sq->addrlen;
  w->outnet = sq->outnet;
  w->on_tcp_waiting_list = 0;
  w->next_waiting = NULL;
  w->cb = callback;
  w->cb_arg = callback_arg;
  w->ssl_upstream = sq->ssl_upstream;
  w->tls_auth_name = sq->tls_auth_name;
  w->timeout = timeout;
  w->id_node.key = NULL;
  w->write_wait_prev = NULL;
  w->write_wait_next = NULL;
  w->write_wait_queued = 0;
  w->error_count = 0;
#ifdef USE_DNSTAP
  w->sq = NULL;
#endif
  w->in_cb_and_decommission = 0;
  if(pend) {
    /* we have a buffer available right now */
    if(reuse) {
      log_assert(reuse == &pend->reuse);
      /* reuse existing fd, write query and continue */
      /* store query in tree by id */
      verbose(VERB_CLIENT, "pending_tcp_query: reuse, store");
      w->next_waiting = (void*)pend;
      reuse_tree_by_id_insert(&pend->reuse, w);
      /* can we write right now? */
      if(pend->query == NULL) {
        /* write straight away */
        /* stop the timer on read of the fd */
        comm_point_stop_listening(pend->c);
        pend->query = w;
        outnet_tcp_take_query_setup(pend->c->fd, pend,
          w);
      } else {
        /* put it in the waiting list for
         * this stream */
        reuse_write_wait_push_back(&pend->reuse, w);
      }
    } else {
      /* create new fd and connect to addr, setup to
       * write query */
      verbose(VERB_CLIENT, "pending_tcp_query: new fd, connect");
      rbtree_init(&pend->reuse.tree_by_id, reuse_id_cmp);
      pend->reuse.pending = pend;
      memcpy(&pend->reuse.addr, &sq->addr, sq->addrlen);
      pend->reuse.addrlen = sq->addrlen;
      if(!outnet_tcp_take_into_use(w)) {
        waiting_tcp_delete(w);
        return NULL;
      }
    }
#ifdef USE_DNSTAP
    if(sq->outnet->dtenv &&
       (sq->outnet->dtenv->log_resolver_query_messages ||
        sq->outnet->dtenv->log_forwarder_query_messages)) {
      /* use w->pkt, because it has the ID value */
      sldns_buffer tmp;
      sldns_buffer_init_frm_data(&tmp, w->pkt, w->pkt_len);
      dt_msg_send_outside_query(sq->outnet->dtenv, &sq->addr,
        &pend->pi->addr, comm_tcp, NULL, sq->zone,
        sq->zonelen, &tmp);
    }
#endif
  } else {
    /* queue up */
    /* waiting for a buffer on the outside network buffer wait
     * list */
    verbose(VERB_CLIENT, "pending_tcp_query: queue to wait");
#ifdef USE_DNSTAP
    w->sq = sq;
#endif
    outnet_waiting_tcp_list_add(sq->outnet, w, 1);
  }
  return w;
}

/** create query for serviced queries */
static void
serviced_gen_query(sldns_buffer* buff, uint8_t* qname, size_t qnamelen, 
  uint16_t qtype, uint16_t qclass, uint16_t flags)
{
  sldns_buffer_clear(buff);
  /* skip id */
  sldns_buffer_write_u16(buff, flags);
  sldns_buffer_write_u16(buff, 1); /* qdcount */
  sldns_buffer_write_u16(buff, 0); /* ancount */
  sldns_buffer_write_u16(buff, 0); /* nscount */
  sldns_buffer_write_u16(buff, 0); /* arcount */
  sldns_buffer_write(buff, qname, qnamelen);
  sldns_buffer_write_u16(buff, qtype);
  sldns_buffer_write_u16(buff, qclass);
  sldns_buffer_flip(buff);
}

/** lookup serviced query in serviced query rbtree */
static struct serviced_query*
lookup_serviced(struct outside_network* outnet, sldns_buffer* buff, int dnssec,
  struct sockaddr_storage* addr, socklen_t addrlen,
  struct edns_option* opt_list)
{
  struct serviced_query key;
  key.node.key = &key;
  key.qbuf = sldns_buffer_begin(buff);
  key.qbuflen = sldns_buffer_limit(buff);
  key.dnssec = dnssec;
  memcpy(&key.addr, addr, addrlen);
  key.addrlen = addrlen;
  key.outnet = outnet;
  key.opt_list = opt_list;
  return (struct serviced_query*)rbtree_search(outnet->serviced, &key);
}

void
serviced_timer_cb(void* arg)
{
  struct serviced_query* sq = (struct serviced_query*)arg;
  struct outside_network* outnet = sq->outnet;
  verbose(VERB_ALGO, "serviced send timer");
  /* By the time this cb is called, if we don't have any registered
   * callbacks for this serviced_query anymore; do not send. */
  if(!sq->cblist)
    goto delete;
  /* perform first network action */
  if(outnet->do_udp && !(sq->tcp_upstream || sq->ssl_upstream)) {
    if(!serviced_udp_send(sq, outnet->udp_buff))
      goto delete;
  } else {
    if(!serviced_tcp_send(sq, outnet->udp_buff))
      goto delete;
  }
  /* Maybe by this time we don't have callbacks attached anymore. Don't
   * proactively try to delete; let it run and maybe another callback
   * will get attached by the time we get an answer. */
  return;
delete:
  serviced_callbacks(sq, NETEVENT_CLOSED, NULL, NULL);
}

/** Create new serviced entry */
static struct serviced_query*
serviced_create(struct outside_network* outnet, sldns_buffer* buff, int dnssec,
  int want_dnssec, int nocaps, int tcp_upstream, int ssl_upstream,
  char* tls_auth_name, struct sockaddr_storage* addr, socklen_t addrlen,
  uint8_t* zone, size_t zonelen, int qtype, struct edns_option* opt_list,
  size_t pad_queries_block_size, struct alloc_cache* alloc,
  struct regional* region)
{
  struct serviced_query* sq = (struct serviced_query*)malloc(sizeof(*sq));
  struct timeval t;
#ifdef UNBOUND_DEBUG
  rbnode_type* ins;
#endif
  if(!sq) {
    alloc_reg_release(alloc, region);
    return NULL;
  }
  sq->node.key = sq;
  sq->alloc = alloc;
  sq->region = region;
  sq->qbuf = regional_alloc_init(region, sldns_buffer_begin(buff),
    sldns_buffer_limit(buff));
  if(!sq->qbuf) {
    alloc_reg_release(alloc, region);
    free(sq);
    return NULL;
  }
  sq->qbuflen = sldns_buffer_limit(buff);
  sq->zone = regional_alloc_init(region, zone, zonelen);
  if(!sq->zone) {
    alloc_reg_release(alloc, region);
    free(sq);
    return NULL;
  }
  sq->zonelen = zonelen;
  sq->qtype = qtype;
  sq->dnssec = dnssec;
  sq->want_dnssec = want_dnssec;
  sq->nocaps = nocaps;
  sq->tcp_upstream = tcp_upstream;
  sq->ssl_upstream = ssl_upstream;
  if(tls_auth_name) {
    sq->tls_auth_name = regional_strdup(region, tls_auth_name);
    if(!sq->tls_auth_name) {
      alloc_reg_release(alloc, region);
      free(sq);
      return NULL;
    }
  } else {
    sq->tls_auth_name = NULL;
  }
  memcpy(&sq->addr, addr, addrlen);
  sq->addrlen = addrlen;
  sq->opt_list = opt_list;
  sq->busy = 0;
  sq->timer = comm_timer_create(outnet->base, serviced_timer_cb, sq);
  if(!sq->timer) {
    alloc_reg_release(alloc, region);
    free(sq);
    return NULL;
  }
  memset(&t, 0, sizeof(t));
  comm_timer_set(sq->timer, &t);
  sq->outnet = outnet;
  sq->cblist = NULL;
  sq->pending = NULL;
  sq->status = serviced_initial;
  sq->retry = 0;
  sq->to_be_deleted = 0;
  sq->padding_block_size = pad_queries_block_size;
#ifdef UNBOUND_DEBUG
  ins =
#else
  (void)
#endif
  rbtree_insert(outnet->serviced, &sq->node);
  log_assert(ins != NULL); /* must not be already present */
  return sq;
}

/** reuse tcp stream, remove serviced query from stream,
 * return true if the stream is kept, false if it is to be closed */
static int
reuse_tcp_remove_serviced_keep(struct waiting_tcp* w,
  struct serviced_query* sq)
{
  struct pending_tcp* pend_tcp = (struct pending_tcp*)w->next_waiting;
  verbose(VERB_CLIENT, "reuse_tcp_remove_serviced_keep");
  /* remove the callback. let query continue to write to not cancel
   * the stream itself.  also keep it as an entry in the tree_by_id,
   * in case the answer returns (that we no longer want), but we cannot
   * pick the same ID number meanwhile */
  w->cb = NULL;
  /* see if can be entered in reuse tree
   * for that the FD has to be non-1 */
  if(pend_tcp->c->fd == -1) {
    verbose(VERB_CLIENT, "reuse_tcp_remove_serviced_keep: -1 fd");
    return 0;
  }
  /* if in tree and used by other queries */
  if(pend_tcp->reuse.node.key) {
    verbose(VERB_CLIENT, "reuse_tcp_remove_serviced_keep: in use by other queries");
    /* do not reset the keepalive timer, for that
     * we'd need traffic, and this is where the serviced is
     * removed due to state machine internal reasons,
     * eg. iterator no longer interested in this query */
    return 1;
  }
  /* if still open and want to keep it open */
  if(pend_tcp->c->fd != -1 && sq->outnet->tcp_reuse.count <
    sq->outnet->tcp_reuse_max) {
    verbose(VERB_CLIENT, "reuse_tcp_remove_serviced_keep: keep open");
    /* set a keepalive timer on it */
    if(!reuse_tcp_insert(sq->outnet, pend_tcp)) {
      return 0;
    }
    reuse_tcp_setup_timeout(pend_tcp, sq->outnet->tcp_reuse_timeout);
    return 1;
  }
  return 0;
}

/** cleanup serviced query entry */
static void
serviced_delete(struct serviced_query* sq)
{
  verbose(VERB_CLIENT, "serviced_delete");
  if(sq->pending) {
    /* clear up the pending query */
    if(sq->status == serviced_query_UDP_EDNS ||
      sq->status == serviced_query_UDP ||
      sq->status == serviced_query_UDP_EDNS_FRAG ||
      sq->status == serviced_query_UDP_EDNS_fallback) {
      struct pending* p = (struct pending*)sq->pending;
      verbose(VERB_CLIENT, "serviced_delete: UDP");
      if(p->pc)
        portcomm_loweruse(sq->outnet, p->pc);
      pending_delete(sq->outnet, p);
      /* this call can cause reentrant calls back into the
       * mesh */
      outnet_send_wait_udp(sq->outnet);
    } else {
      struct waiting_tcp* w = (struct waiting_tcp*)
        sq->pending;
      verbose(VERB_CLIENT, "serviced_delete: TCP");
      log_assert(!(w->write_wait_queued && w->on_tcp_waiting_list));
      /* if on stream-write-waiting list then
       * remove from waiting list and waiting_tcp_delete */
      if(w->write_wait_queued) {
        struct pending_tcp* pend =
          (struct pending_tcp*)w->next_waiting;
        verbose(VERB_CLIENT, "serviced_delete: writewait");
        if(!w->in_cb_and_decommission)
          reuse_tree_by_id_delete(&pend->reuse, w);
        reuse_write_wait_remove(&pend->reuse, w);
        if(!w->in_cb_and_decommission)
          waiting_tcp_delete(w);
      } else if(!w->on_tcp_waiting_list) {
        struct pending_tcp* pend =
          (struct pending_tcp*)w->next_waiting;
        verbose(VERB_CLIENT, "serviced_delete: tcpreusekeep");
        /* w needs to stay on tree_by_id to not assign
         * the same ID; remove the callback since its
         * serviced_query will be gone. */
        w->cb = NULL;
        if(!reuse_tcp_remove_serviced_keep(w, sq)) {
          if(!w->in_cb_and_decommission)
            reuse_cb_and_decommission(sq->outnet,
              pend, NETEVENT_CLOSED);
          use_free_buffer(sq->outnet);
        }
        sq->pending = NULL;
      } else {
        verbose(VERB_CLIENT, "serviced_delete: tcpwait");
        outnet_waiting_tcp_list_remove(sq->outnet, w);
        if(!w->in_cb_and_decommission)
          waiting_tcp_delete(w);
      }
    }
  }
  /* does not delete from tree, caller has to do that */
  serviced_node_del(&sq->node, NULL);
}

/** perturb a dname capitalization randomly */
static void
serviced_perturb_qname(struct ub_randstate* rnd, uint8_t* qbuf, size_t len)
{
  uint8_t lablen;
  uint8_t* d = qbuf + 10;
  long int random = 0;
  int bits = 0;
  log_assert(len >= 10 + 5 /* offset qname, root, qtype, qclass */);
  (void)len;
  lablen = *d++;
  while(lablen) {
    while(lablen--) {
      /* only perturb A-Z, a-z */
      if(isalpha((unsigned char)*d)) {
        /* get a random bit */  
        if(bits == 0) {
          random = ub_random(rnd);
          bits = 30;
        }
        if((random & 0x1)) {
          *d = (uint8_t)toupper((unsigned char)*d);
        } else {
          *d = (uint8_t)tolower((unsigned char)*d);
        }
        random >>= 1;
        bits--;
      }
      d++;
    }
    lablen = *d++;
  }
  if(verbosity >= VERB_ALGO) {
    char buf[LDNS_MAX_DOMAINLEN];
    dname_str(qbuf+10, buf);
    verbose(VERB_ALGO, "qname perturbed to %s", buf);
  }
}

static uint16_t
serviced_query_udp_size(struct serviced_query* sq, enum serviced_query_status status) {
  uint16_t udp_size;
  if(status == serviced_query_UDP_EDNS_FRAG) {
    if(addr_is_ip6(&sq->addr, sq->addrlen)) {
      if(EDNS_FRAG_SIZE_IP6 < EDNS_ADVERTISED_SIZE)
        udp_size = EDNS_FRAG_SIZE_IP6;
      else  udp_size = EDNS_ADVERTISED_SIZE;
    } else {
      if(EDNS_FRAG_SIZE_IP4 < EDNS_ADVERTISED_SIZE)
        udp_size = EDNS_FRAG_SIZE_IP4;
      else  udp_size = EDNS_ADVERTISED_SIZE;
    }
  } else {
    udp_size = EDNS_ADVERTISED_SIZE;
  }
  return udp_size;
}

/** put serviced query into a buffer */
static void
serviced_encode(struct serviced_query* sq, sldns_buffer* buff, int with_edns)
{
  /* if we are using 0x20 bits for ID randomness, perturb them */
  if(sq->outnet->use_caps_for_id && !sq->nocaps) {
    serviced_perturb_qname(sq->outnet->rnd, sq->qbuf, sq->qbuflen);
  }
  /* generate query */
  sldns_buffer_clear(buff);
  sldns_buffer_write_u16(buff, 0); /* id placeholder */
  sldns_buffer_write(buff, sq->qbuf, sq->qbuflen);
  sldns_buffer_flip(buff);
  if(with_edns) {
    /* add edns section */
    struct edns_data edns;
    struct edns_option padding_option;
    edns.edns_present = 1;
    edns.ext_rcode = 0;
    edns.edns_version = EDNS_ADVERTISED_VERSION;
    edns.opt_list_in = NULL;
    edns.opt_list_out = sq->opt_list;
    edns.opt_list_inplace_cb_out = NULL;
    edns.udp_size = serviced_query_udp_size(sq, sq->status);
    edns.bits = 0;
    if((sq->dnssec & EDNS_DO))
      edns.bits = EDNS_DO;
    if((sq->dnssec & BIT_CD))
      LDNS_CD_SET(sldns_buffer_begin(buff));
    if (sq->ssl_upstream && sq->padding_block_size) {
      padding_option.opt_code = LDNS_EDNS_PADDING;
      padding_option.opt_len = 0;
      padding_option.opt_data = NULL;
      padding_option.next = edns.opt_list_out;
      edns.opt_list_out = &padding_option;
      edns.padding_block_size = sq->padding_block_size;
    }
    attach_edns_record(buff, &edns);
  }
}

/**
 * Perform serviced query UDP sending operation.
 * Sends UDP with EDNS, unless infra host marked non EDNS.
 * @param sq: query to send.
 * @param buff: buffer scratch space.
 * @return 0 on error.
 */
static int
serviced_udp_send(struct serviced_query* sq, sldns_buffer* buff)
{
  int rtt, vs;
  uint8_t edns_lame_known;
  time_t now = *sq->outnet->now_secs;

  if(!infra_host(sq->outnet->infra, &sq->addr, sq->addrlen, sq->zone,
    sq->zonelen, now, &vs, &edns_lame_known, &rtt))
    return 0;
  sq->last_rtt = rtt;
  verbose(VERB_ALGO, "EDNS lookup known=%d vs=%d", edns_lame_known, vs);
  if(sq->status == serviced_initial) {
    if(vs != -1) {
      sq->status = serviced_query_UDP_EDNS;
    } else {   
      sq->status = serviced_query_UDP; 
    }
  }
  serviced_encode(sq, buff, (sq->status == serviced_query_UDP_EDNS) ||
    (sq->status == serviced_query_UDP_EDNS_FRAG));
  sq->last_sent_time = *sq->outnet->now_tv;
  sq->edns_lame_known = (int)edns_lame_known;
  verbose(VERB_ALGO, "serviced query UDP timeout=%d msec", rtt);
  sq->pending = pending_udp_query(sq, buff, rtt,
    serviced_udp_callback, sq);
  if(!sq->pending)
    return 0;
  return 1;
}

/** check that perturbed qname is identical */
static int
serviced_check_qname(sldns_buffer* pkt, uint8_t* qbuf, size_t qbuflen)
{
  uint8_t* d1 = sldns_buffer_begin(pkt)+12;
  uint8_t* d2 = qbuf+10;
  uint8_t len1, len2;
  int count = 0;
  if(sldns_buffer_limit(pkt) < 12+1+4) /* packet too small for qname */
    return 0;
  log_assert(qbuflen >= 15 /* 10 header, root, type, class */);
  len1 = *d1++;
  len2 = *d2++;
  while(len1 != 0 || len2 != 0) {
    if(LABEL_IS_PTR(len1)) {
      /* check if we can read *d1 with compression ptr rest */
      if(d1 >= sldns_buffer_at(pkt, sldns_buffer_limit(pkt)))
        return 0;
      d1 = sldns_buffer_begin(pkt)+PTR_OFFSET(len1, *d1);
      /* check if we can read the destination *d1 */
      if(d1 >= sldns_buffer_at(pkt, sldns_buffer_limit(pkt)))
        return 0;
      len1 = *d1++;
      if(count++ > MAX_COMPRESS_PTRS)
        return 0;
      continue;
    }
    if(d2 > qbuf+qbuflen)
      return 0;
    if(len1 != len2)
      return 0;
    if(len1 > LDNS_MAX_LABELLEN)
      return 0;
    /* check len1 + 1(next length) are okay to read */
    if(d1+len1 >= sldns_buffer_at(pkt, sldns_buffer_limit(pkt)))
      return 0;
    log_assert(len1 <= LDNS_MAX_LABELLEN);
    log_assert(len2 <= LDNS_MAX_LABELLEN);
    log_assert(len1 == len2 && len1 != 0);
    /* compare the labels - bitwise identical */
    if(memcmp(d1, d2, len1) != 0)
      return 0;
    d1 += len1;
    d2 += len2;
    len1 = *d1++;
    len2 = *d2++;
  }
  return 1;
}

/** call the callbacks for a serviced query */
static void
serviced_callbacks(struct serviced_query* sq, int error, struct comm_point* c,
  struct comm_reply* rep)
{
  struct service_callback* p;
  int dobackup = (sq->cblist && sq->cblist->next); /* >1 cb*/
  uint8_t *backup_p = NULL;
  size_t backlen = 0;
#ifdef UNBOUND_DEBUG
  rbnode_type* rem =
#else
  (void)
#endif
  /* remove from tree, and schedule for deletion, so that callbacks
   * can safely deregister themselves and even create new serviced
   * queries that are identical to this one. */
  rbtree_delete(sq->outnet->serviced, sq);
  log_assert(rem); /* should have been present */
  sq->to_be_deleted = 1; 
  verbose(VERB_ALGO, "svcd callbacks start");
  if(sq->outnet->use_caps_for_id && error == NETEVENT_NOERROR && c &&
    !sq->nocaps && sq->qtype != LDNS_RR_TYPE_PTR) {
    /* for type PTR do not check perturbed name in answer,
     * compatibility with cisco dns guard boxes that mess up
     * reverse queries 0x20 contents */
    /* noerror and nxdomain must have a qname in reply */
    if(sldns_buffer_read_u16_at(c->buffer, 4) == 0 &&
      (LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer))
        == LDNS_RCODE_NOERROR || 
       LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer))
        == LDNS_RCODE_NXDOMAIN)) {
      verbose(VERB_DETAIL, "no qname in reply to check 0x20ID");
      log_addr(VERB_DETAIL, "from server", 
        &sq->addr, sq->addrlen);
      log_buf(VERB_DETAIL, "for packet", c->buffer);
      error = NETEVENT_CLOSED;
      c = NULL;
    } else if(sldns_buffer_read_u16_at(c->buffer, 4) > 0 &&
      !serviced_check_qname(c->buffer, sq->qbuf, 
      sq->qbuflen)) {
      verbose(VERB_DETAIL, "wrong 0x20-ID in reply qname");
      log_addr(VERB_DETAIL, "from server", 
        &sq->addr, sq->addrlen);
      log_buf(VERB_DETAIL, "for packet", c->buffer);
      error = NETEVENT_CAPSFAIL;
      /* and cleanup too */
      pkt_dname_tolower(c->buffer, 
        sldns_buffer_at(c->buffer, 12));
    } else {
      verbose(VERB_ALGO, "good 0x20-ID in reply qname");
      /* cleanup caps, prettier cache contents. */
      pkt_dname_tolower(c->buffer, 
        sldns_buffer_at(c->buffer, 12));
    }
  }
  if(dobackup && c) {
    /* make a backup of the query, since the querystate processing
     * may send outgoing queries that overwrite the buffer.
     * use secondary buffer to store the query.
     * This is a data copy, but faster than packet to server */
    backlen = sldns_buffer_limit(c->buffer);
    backup_p = regional_alloc_init(sq->region,
      sldns_buffer_begin(c->buffer), backlen);
    if(!backup_p) {
      log_err("malloc failure in serviced query callbacks");
      error = NETEVENT_CLOSED;
      c = NULL;
    }
    sq->outnet->svcd_overhead = backlen;
  }
  /* test the actual sq->cblist, because the next elem could be deleted*/
  while((p=sq->cblist) != NULL) {
    sq->cblist = p->next; /* remove this element */
    if(dobackup && c) {
      sldns_buffer_clear(c->buffer);
      sldns_buffer_write(c->buffer, backup_p, backlen);
      sldns_buffer_flip(c->buffer);
    }
    fptr_ok(fptr_whitelist_serviced_query(p->cb));
    (void)(*p->cb)(c, p->cb_arg, error, rep);
  }
  if(backup_p) {
    sq->outnet->svcd_overhead = 0;
  }
  verbose(VERB_ALGO, "svcd callbacks end");
  log_assert(sq->cblist == NULL);
  serviced_delete(sq);
}

int 
serviced_tcp_callback(struct comm_point* c, void* arg, int error,
        struct comm_reply* rep)
{
  struct serviced_query* sq = (struct serviced_query*)arg;
  struct comm_reply r2;
#ifdef USE_DNSTAP
  struct waiting_tcp* w = (struct waiting_tcp*)sq->pending;
  struct pending_tcp* pend_tcp = NULL;
  struct port_if* pi = NULL;
  if(w && !w->on_tcp_waiting_list && w->next_waiting) {
    pend_tcp = (struct pending_tcp*)w->next_waiting;
    pi = pend_tcp->pi;
  }
#endif
  sq->pending = NULL; /* removed after this callback */
  if(error != NETEVENT_NOERROR)
    log_addr(VERB_QUERY, "tcp error for address", 
      &sq->addr, sq->addrlen);
  if(error==NETEVENT_NOERROR)
    infra_update_tcp_works(sq->outnet->infra, &sq->addr,
      sq->addrlen, sq->zone, sq->zonelen);
#ifdef USE_DNSTAP
  /*
   * sending src (local service)/dst (upstream) addresses over DNSTAP
   */
  if(error==NETEVENT_NOERROR && pi && sq->outnet->dtenv &&
     (sq->outnet->dtenv->log_resolver_response_messages ||
      sq->outnet->dtenv->log_forwarder_response_messages)) {
    log_addr(VERB_ALGO, "response from upstream", &sq->addr, sq->addrlen);
    log_addr(VERB_ALGO, "to local addr", &pi->addr, pi->addrlen);
    dt_msg_send_outside_response(sq->outnet->dtenv, &sq->addr,
      &pi->addr, c->type, c->ssl, sq->zone, sq->zonelen, sq->qbuf,
      sq->qbuflen, &sq->last_sent_time, sq->outnet->now_tv,
      c->buffer);
  }
#endif
  if(error==NETEVENT_NOERROR && sq->status == serviced_query_TCP_EDNS &&
    (LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == 
    LDNS_RCODE_FORMERR || LDNS_RCODE_WIRE(sldns_buffer_begin(
    c->buffer)) == LDNS_RCODE_NOTIMPL) ) {
    /* attempt to fallback to nonEDNS */
    sq->status = serviced_query_TCP_EDNS_fallback;
    serviced_tcp_initiate(sq, c->buffer);
    return 0;
  } else if(error==NETEVENT_NOERROR && 
    sq->status == serviced_query_TCP_EDNS_fallback &&
      (LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == 
      LDNS_RCODE_NOERROR || LDNS_RCODE_WIRE(
      sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NXDOMAIN 
      || LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) 
      == LDNS_RCODE_YXDOMAIN)) {
    /* the fallback produced a result that looks promising, note
     * that this server should be approached without EDNS */
    /* only store noEDNS in cache if domain is noDNSSEC */
    if(!sq->want_dnssec)
      if(!infra_edns_update(sq->outnet->infra, &sq->addr, 
      sq->addrlen, sq->zone, sq->zonelen, -1,
      *sq->outnet->now_secs))
      log_err("Out of memory caching no edns for host");
    sq->status = serviced_query_TCP;
  }
  if(sq->tcp_upstream || sq->ssl_upstream) {
      struct timeval now = *sq->outnet->now_tv;
      if(error!=NETEVENT_NOERROR) {
          if(!infra_rtt_update(sq->outnet->infra, &sq->addr,
        sq->addrlen, sq->zone, sq->zonelen, sq->qtype,
        -1, sq->last_rtt, (time_t)now.tv_sec))
        log_err("out of memory in TCP exponential backoff.");
      } else if(now.tv_sec > sq->last_sent_time.tv_sec ||
    (now.tv_sec == sq->last_sent_time.tv_sec &&
    now.tv_usec > sq->last_sent_time.tv_usec)) {
    /* convert from microseconds to milliseconds */
    int roundtime = ((int)(now.tv_sec - sq->last_sent_time.tv_sec))*1000
      + ((int)now.tv_usec - (int)sq->last_sent_time.tv_usec)/1000;
    verbose(VERB_ALGO, "measured TCP-time at %d msec", roundtime);
    log_assert(roundtime >= 0);
    /* only store if less then AUTH_TIMEOUT seconds, it could be
     * huge due to system-hibernated and we woke up */
    if(roundtime < 60000) {
        if(!infra_rtt_update(sq->outnet->infra, &sq->addr,
      sq->addrlen, sq->zone, sq->zonelen, sq->qtype,
      roundtime, sq->last_rtt, (time_t)now.tv_sec))
      log_err("out of memory noting rtt.");
    }
      }
  }
  /* insert address into reply info */
  if(!rep) {
    /* create one if there isn't (on errors) */
    rep = &r2;
    r2.c = c;
  }
  memcpy(&rep->remote_addr, &sq->addr, sq->addrlen);
  rep->remote_addrlen = sq->addrlen;
  serviced_callbacks(sq, error, c, rep);
  return 0;
}

static void
serviced_tcp_initiate(struct serviced_query* sq, sldns_buffer* buff)
{
  verbose(VERB_ALGO, "initiate TCP query %s", 
    sq->status==serviced_query_TCP_EDNS?"EDNS":"");
  serviced_encode(sq, buff, sq->status == serviced_query_TCP_EDNS);
  sq->last_sent_time = *sq->outnet->now_tv;
  log_assert(!sq->busy);
  sq->busy = 1;
  sq->pending = pending_tcp_query(sq, buff, sq->outnet->tcp_auth_query_timeout,
    serviced_tcp_callback, sq);
  sq->busy = 0;
  if(!sq->pending) {
    /* delete from tree so that a retry by above layer does not
     * clash with this entry */
    verbose(VERB_ALGO, "serviced_tcp_initiate: failed to send tcp query");
    serviced_callbacks(sq, NETEVENT_CLOSED, NULL, NULL);
  }
}

/** Send serviced query over TCP return false on initial failure */
static int
serviced_tcp_send(struct serviced_query* sq, sldns_buffer* buff)
{
  int vs, rtt, timeout;
  uint8_t edns_lame_known;
  if(!infra_host(sq->outnet->infra, &sq->addr, sq->addrlen, sq->zone,
    sq->zonelen, *sq->outnet->now_secs, &vs, &edns_lame_known,
    &rtt))
    return 0;
  sq->last_rtt = rtt;
  if(vs != -1)
    sq->status = serviced_query_TCP_EDNS;
  else  sq->status = serviced_query_TCP;
  serviced_encode(sq, buff, sq->status == serviced_query_TCP_EDNS);
  sq->last_sent_time = *sq->outnet->now_tv;
  if(sq->tcp_upstream || sq->ssl_upstream) {
    timeout = rtt;
    if(rtt >= UNKNOWN_SERVER_NICENESS && rtt < sq->outnet->tcp_auth_query_timeout)
      timeout = sq->outnet->tcp_auth_query_timeout;
  } else {
    timeout = sq->outnet->tcp_auth_query_timeout;
  }
  log_assert(!sq->busy);
  sq->busy = 1;
  sq->pending = pending_tcp_query(sq, buff, timeout,
    serviced_tcp_callback, sq);
  sq->busy = 0;
  return sq->pending != NULL;
}

/* see if packet is edns malformed; got zeroes at start.
 * This is from servers that return malformed packets to EDNS0 queries,
 * but they return good packets for nonEDNS0 queries.
 * We try to detect their output; without resorting to a full parse or
 * check for too many bytes after the end of the packet. */
static int
packet_edns_malformed(struct sldns_buffer* buf, int qtype)
{
  size_t len;
  if(sldns_buffer_limit(buf) < LDNS_HEADER_SIZE)
    return 1; /* malformed */
  /* they have NOERROR rcode, 1 answer. */
  if(LDNS_RCODE_WIRE(sldns_buffer_begin(buf)) != LDNS_RCODE_NOERROR)
    return 0;
  /* one query (to skip) and answer records */
  if(LDNS_QDCOUNT(sldns_buffer_begin(buf)) != 1 ||
    LDNS_ANCOUNT(sldns_buffer_begin(buf)) == 0)
    return 0;
  /* skip qname */
  len = dname_valid(sldns_buffer_at(buf, LDNS_HEADER_SIZE),
    sldns_buffer_limit(buf)-LDNS_HEADER_SIZE);
  if(len == 0)
    return 0;
  if(len == 1 && qtype == 0)
    return 0; /* we asked for '.' and type 0 */
  /* and then 4 bytes (type and class of query) */
  if(sldns_buffer_limit(buf) < LDNS_HEADER_SIZE + len + 4 + 3)
    return 0;

  /* and start with 11 zeroes as the answer RR */
  /* so check the qtype of the answer record, qname=0, type=0 */
  if(sldns_buffer_at(buf, LDNS_HEADER_SIZE+len+4)[0] == 0 &&
     sldns_buffer_at(buf, LDNS_HEADER_SIZE+len+4)[1] == 0 &&
     sldns_buffer_at(buf, LDNS_HEADER_SIZE+len+4)[2] == 0)
    return 1;
  return 0;
}

int 
serviced_udp_callback(struct comm_point* c, void* arg, int error,
        struct comm_reply* rep)
{
  struct serviced_query* sq = (struct serviced_query*)arg;
  struct outside_network* outnet = sq->outnet;
  struct timeval now = *sq->outnet->now_tv;
#ifdef USE_DNSTAP
  struct pending* p = (struct pending*)sq->pending;
#endif

  sq->pending = NULL; /* removed after callback */
  if(error == NETEVENT_TIMEOUT) {
    if(sq->status == serviced_query_UDP_EDNS && sq->last_rtt < 5000 &&
       (serviced_query_udp_size(sq, serviced_query_UDP_EDNS_FRAG) < serviced_query_udp_size(sq, serviced_query_UDP_EDNS))) {
      /* fallback to 1480/1280 */
      sq->status = serviced_query_UDP_EDNS_FRAG;
      log_name_addr(VERB_ALGO, "try edns1xx0", sq->qbuf+10,
        &sq->addr, sq->addrlen);
      if(!serviced_udp_send(sq, c->buffer)) {
        serviced_callbacks(sq, NETEVENT_CLOSED, c, rep);
      }
      return 0;
    }
    if(sq->status == serviced_query_UDP_EDNS_FRAG) {
      /* fragmentation size did not fix it */
      sq->status = serviced_query_UDP_EDNS;
    }
    sq->retry++;
    if(!infra_rtt_update(outnet->infra, &sq->addr, sq->addrlen,
      sq->zone, sq->zonelen, sq->qtype, -1, sq->last_rtt,
      (time_t)now.tv_sec))
      log_err("out of memory in UDP exponential backoff");
    if(sq->retry < OUTBOUND_UDP_RETRY) {
      log_name_addr(VERB_ALGO, "retry query", sq->qbuf+10,
        &sq->addr, sq->addrlen);
      if(!serviced_udp_send(sq, c->buffer)) {
        serviced_callbacks(sq, NETEVENT_CLOSED, c, rep);
      }
      return 0;
    }
  }
  if(error != NETEVENT_NOERROR) {
    /* udp returns error (due to no ID or interface available) */
    serviced_callbacks(sq, error, c, rep);
    return 0;
  }
#ifdef USE_DNSTAP
  /*
   * sending src (local service)/dst (upstream) addresses over DNSTAP
   */
  if(error == NETEVENT_NOERROR && outnet->dtenv && p->pc &&
    (outnet->dtenv->log_resolver_response_messages ||
    outnet->dtenv->log_forwarder_response_messages)) {
    log_addr(VERB_ALGO, "response from upstream", &sq->addr, sq->addrlen);
    log_addr(VERB_ALGO, "to local addr", &p->pc->pif->addr,
      p->pc->pif->addrlen);
    dt_msg_send_outside_response(outnet->dtenv, &sq->addr,
      &p->pc->pif->addr, c->type, c->ssl, sq->zone, sq->zonelen,
      sq->qbuf, sq->qbuflen, &sq->last_sent_time,
      sq->outnet->now_tv, c->buffer);
  }
#endif
  if( (sq->status == serviced_query_UDP_EDNS 
    ||sq->status == serviced_query_UDP_EDNS_FRAG)
    && (LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) 
      == LDNS_RCODE_FORMERR || LDNS_RCODE_WIRE(
      sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NOTIMPL
        || packet_edns_malformed(c->buffer, sq->qtype)
      )) {
    /* try to get an answer by falling back without EDNS */
    verbose(VERB_ALGO, "serviced query: attempt without EDNS");
    sq->status = serviced_query_UDP_EDNS_fallback;
    sq->retry = 0;
    if(!serviced_udp_send(sq, c->buffer)) {
      serviced_callbacks(sq, NETEVENT_CLOSED, c, rep);
    }
    return 0;
  } else if(sq->status == serviced_query_UDP_EDNS && 
    !sq->edns_lame_known) {
    /* now we know that edns queries received answers store that */
    log_addr(VERB_ALGO, "serviced query: EDNS works for",
      &sq->addr, sq->addrlen);
    if(!infra_edns_update(outnet->infra, &sq->addr, sq->addrlen, 
      sq->zone, sq->zonelen, 0, (time_t)now.tv_sec)) {
      log_err("Out of memory caching edns works");
    }
    sq->edns_lame_known = 1;
  } else if(sq->status == serviced_query_UDP_EDNS_fallback &&
    !sq->edns_lame_known && (LDNS_RCODE_WIRE(
    sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NOERROR || 
    LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == 
    LDNS_RCODE_NXDOMAIN || LDNS_RCODE_WIRE(sldns_buffer_begin(
    c->buffer)) == LDNS_RCODE_YXDOMAIN)) {
    /* the fallback produced a result that looks promising, note
     * that this server should be approached without EDNS */
    /* only store noEDNS in cache if domain is noDNSSEC */
    if(!sq->want_dnssec) {
      log_addr(VERB_ALGO, "serviced query: EDNS fails for",
      &sq->addr, sq->addrlen);
      if(!infra_edns_update(outnet->infra, &sq->addr, sq->addrlen,
      sq->zone, sq->zonelen, -1, (time_t)now.tv_sec)) {
      log_err("Out of memory caching no edns for host");
      }
    } else {
      log_addr(VERB_ALGO, "serviced query: EDNS fails, but "
      "not stored because need DNSSEC for", &sq->addr,
      sq->addrlen);
    }
    sq->status = serviced_query_UDP;
  }
  if(now.tv_sec > sq->last_sent_time.tv_sec ||
    (now.tv_sec == sq->last_sent_time.tv_sec &&
    now.tv_usec > sq->last_sent_time.tv_usec)) {
    /* convert from microseconds to milliseconds */
    int roundtime = ((int)(now.tv_sec - sq->last_sent_time.tv_sec))*1000
      + ((int)now.tv_usec - (int)sq->last_sent_time.tv_usec)/1000;
    verbose(VERB_ALGO, "measured roundtrip at %d msec", roundtime);
    log_assert(roundtime >= 0);
    /* in case the system hibernated, do not enter a huge value,
     * above this value gives trouble with server selection */
    if(roundtime < 60000) {
        if(!infra_rtt_update(outnet->infra, &sq->addr, sq->addrlen, 
      sq->zone, sq->zonelen, sq->qtype, roundtime,
      sq->last_rtt, (time_t)now.tv_sec))
      log_err("out of memory noting rtt.");
    }
  }
  /* perform TC flag check and TCP fallback after updating our
   * cache entries for EDNS status and RTT times */
  if(LDNS_TC_WIRE(sldns_buffer_begin(c->buffer))) {
    /* fallback to TCP */
    /* this discards partial UDP contents */
    if(sq->status == serviced_query_UDP_EDNS ||
      sq->status == serviced_query_UDP_EDNS_FRAG ||
      sq->status == serviced_query_UDP_EDNS_fallback)
      /* if we have unfinished EDNS_fallback, start again */
      sq->status = serviced_query_TCP_EDNS;
    else  sq->status = serviced_query_TCP;
    serviced_tcp_initiate(sq, c->buffer);
    return 0;
  }
  /* yay! an answer */
  serviced_callbacks(sq, error, c, rep);
  return 0;
}

struct serviced_query* 
outnet_serviced_query(struct outside_network* outnet,
  struct query_info* qinfo, uint16_t flags, int dnssec, int want_dnssec,
  int nocaps, int check_ratelimit, int tcp_upstream, int ssl_upstream,
  char* tls_auth_name, struct sockaddr_storage* addr, socklen_t addrlen,
  uint8_t* zone, size_t zonelen, struct module_qstate* qstate,
  comm_point_callback_type* callback, void* callback_arg,
  sldns_buffer* buff, struct module_env* env, int* was_ratelimited)
{
  struct serviced_query* sq;
  struct service_callback* cb;
  struct edns_string_addr* client_string_addr;
  struct regional* region;
  struct edns_option* backed_up_opt_list = qstate->edns_opts_back_out;
  struct edns_option* per_upstream_opt_list = NULL;
  time_t timenow = 0;

  /* If we have an already populated EDNS option list make a copy since
   * we may now add upstream specific EDNS options. */
  /* Use a region that could be attached to a serviced_query, if it needs
   * to be created. If an existing one is found then this region will be
   * destroyed here. */
  region = alloc_reg_obtain(env->alloc);
  if(!region) return NULL;
  if(qstate->edns_opts_back_out) {
    per_upstream_opt_list = edns_opt_copy_region(
      qstate->edns_opts_back_out, region);
    if(!per_upstream_opt_list) {
      alloc_reg_release(env->alloc, region);
      return NULL;
    }
    qstate->edns_opts_back_out = per_upstream_opt_list;
  }

  if(!inplace_cb_query_call(env, qinfo, flags, addr, addrlen, zone,
    zonelen, qstate, region)) {
    alloc_reg_release(env->alloc, region);
    return NULL;
  }
  /* Restore the option list; we can explicitly use the copied one from
   * now on. */
  per_upstream_opt_list = qstate->edns_opts_back_out;
  qstate->edns_opts_back_out = backed_up_opt_list;

  if((client_string_addr = edns_string_addr_lookup(
    &env->edns_strings->client_strings, addr, addrlen))) {
    edns_opt_list_append(&per_upstream_opt_list,
      env->edns_strings->client_string_opcode,
      client_string_addr->string_len,
      client_string_addr->string, region);
  }

  serviced_gen_query(buff, qinfo->qname, qinfo->qname_len, qinfo->qtype,
    qinfo->qclass, flags);
  sq = lookup_serviced(outnet, buff, dnssec, addr, addrlen,
    per_upstream_opt_list);
  if(!sq) {
    /* Check ratelimit only for new serviced_query */
    if(check_ratelimit) {
      timenow = *env->now;
      if(!infra_ratelimit_inc(env->infra_cache, zone,
        zonelen, timenow, env->cfg->ratelimit_backoff,
        &qstate->qinfo,
        qstate->mesh_info->reply_list
          ?&qstate->mesh_info->reply_list->query_reply
          :NULL)) {
        /* Can we pass through with slip factor? */
        if(env->cfg->ratelimit_factor == 0 ||
          ub_random_max(env->rnd,
          env->cfg->ratelimit_factor) != 1) {
          *was_ratelimited = 1;
          alloc_reg_release(env->alloc, region);
          return NULL;
        }
        log_nametypeclass(VERB_ALGO,
          "ratelimit allowed through for "
          "delegation point", zone,
          LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
      }
    }
    /* make new serviced query entry */
    sq = serviced_create(outnet, buff, dnssec, want_dnssec, nocaps,
      tcp_upstream, ssl_upstream, tls_auth_name, addr,
      addrlen, zone, zonelen, (int)qinfo->qtype,
      per_upstream_opt_list,
      ( ssl_upstream && env->cfg->pad_queries
      ? env->cfg->pad_queries_block_size : 0 ),
      env->alloc, region);
    if(!sq) {
      if(check_ratelimit) {
        infra_ratelimit_dec(env->infra_cache,
          zone, zonelen, timenow);
      }
      return NULL;
    }
    if(!(cb = (struct service_callback*)regional_alloc(
      sq->region, sizeof(*cb)))) {
      if(check_ratelimit) {
        infra_ratelimit_dec(env->infra_cache,
          zone, zonelen, timenow);
      }
      (void)rbtree_delete(outnet->serviced, sq);
      serviced_node_del(&sq->node, NULL);
      return NULL;
    }
    /* No network action at this point; it will be invoked with the
     * serviced_query timer instead to run outside of the mesh. */
  } else {
    /* We don't need this region anymore. */
    alloc_reg_release(env->alloc, region);
    /* duplicate entries are included in the callback list, because
     * there is a counterpart registration by our caller that needs
     * to be doubly-removed (with callbacks perhaps). */
    if(!(cb = (struct service_callback*)regional_alloc(
      sq->region, sizeof(*cb)))) {
      return NULL;
    }
  }
  /* add callback to list of callbacks */
  cb->cb = callback;
  cb->cb_arg = callback_arg;
  cb->next = sq->cblist;
  sq->cblist = cb;
  return sq;
}

/** remove callback from list */
static void
callback_list_remove(struct serviced_query* sq, void* cb_arg)
{
  struct service_callback** pp = &sq->cblist;
  while(*pp) {
    if((*pp)->cb_arg == cb_arg) {
      struct service_callback* del = *pp;
      *pp = del->next;
      return;
    }
    pp = &(*pp)->next;
  }
}

void outnet_serviced_query_stop(struct serviced_query* sq, void* cb_arg)
{
  if(!sq)
    return;
  callback_list_remove(sq, cb_arg);
  /* if callbacks() routine scheduled deletion, let it do that */
  if(!sq->cblist && !sq->busy && !sq->to_be_deleted) {
    (void)rbtree_delete(sq->outnet->serviced, sq);
    serviced_delete(sq);
  }
}

/** create fd to send to this destination */
static int
fd_for_dest(struct outside_network* outnet, struct sockaddr_storage* to_addr,
  socklen_t to_addrlen)
{
  struct sockaddr_storage* addr;
  socklen_t addrlen;
  int i, try, pnum, dscp;
  struct port_if* pif;

  /* create fd */
  dscp = outnet->ip_dscp;
  for(try = 0; try<1000; try++) {
    int port = 0;
    int freebind = 0;
    int noproto = 0;
    int inuse = 0;
    int fd = -1;

    /* select interface */
    if(addr_is_ip6(to_addr, to_addrlen)) {
      if(outnet->num_ip6 == 0) {
        char to[64];
        addr_to_str(to_addr, to_addrlen, to, sizeof(to));
        verbose(VERB_QUERY, "need ipv6 to send, but no ipv6 outgoing interfaces, for %s", to);
        return -1;
      }
      i = ub_random_max(outnet->rnd, outnet->num_ip6);
      pif = &outnet->ip6_ifs[i];
    } else {
      if(outnet->num_ip4 == 0) {
        char to[64];
        addr_to_str(to_addr, to_addrlen, to, sizeof(to));
        verbose(VERB_QUERY, "need ipv4 to send, but no ipv4 outgoing interfaces, for %s", to);
        return -1;
      }
      i = ub_random_max(outnet->rnd, outnet->num_ip4);
      pif = &outnet->ip4_ifs[i];
    }
    addr = &pif->addr;
    addrlen = pif->addrlen;
#ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
    pnum = ub_random_max(outnet->rnd, pif->avail_total);
    if(pnum < pif->inuse) {
      /* port already open */
      port = pif->out[pnum]->number;
    } else {
      /* unused ports in start part of array */
      port = pif->avail_ports[pnum - pif->inuse];
    }
#else
    pnum = port = 0;
#endif
    if(addr_is_ip6(to_addr, to_addrlen)) {
      struct sockaddr_in6 sa = *(struct sockaddr_in6*)addr;
      sa.sin6_port = (in_port_t)htons((uint16_t)port);
      fd = create_udp_sock(AF_INET6, SOCK_DGRAM,
        (struct sockaddr*)&sa, addrlen, 1, &inuse, &noproto,
        0, 0, 0, NULL, 0, freebind, 0, dscp);
    } else {
      struct sockaddr_in* sa = (struct sockaddr_in*)addr;
      sa->sin_port = (in_port_t)htons((uint16_t)port);
      fd = create_udp_sock(AF_INET, SOCK_DGRAM, 
        (struct sockaddr*)addr, addrlen, 1, &inuse, &noproto,
        0, 0, 0, NULL, 0, freebind, 0, dscp);
    }
    if(fd != -1) {
      return fd;
    }
    if(!inuse) {
      return -1;
    }
  }
  /* too many tries */
  log_err("cannot send probe, ports are in use");
  return -1;
}

struct comm_point*
outnet_comm_point_for_udp(struct outside_network* outnet,
  comm_point_callback_type* cb, void* cb_arg,
  struct sockaddr_storage* to_addr, socklen_t to_addrlen)
{
  struct comm_point* cp;
  int fd = fd_for_dest(outnet, to_addr, to_addrlen);
  if(fd == -1) {
    return NULL;
  }
  cp = comm_point_create_udp(outnet->base, fd, outnet->udp_buff, 0,
    cb, cb_arg, NULL);
  if(!cp) {
    log_err("malloc failure");
    close(fd);
    return NULL;
  }
  return cp;
}

/** setup SSL for comm point */
static int
setup_comm_ssl(struct comm_point* cp, struct outside_network* outnet,
  int fd, char* host)
{
  cp->ssl = outgoing_ssl_fd(outnet->sslctx, fd);
  if(!cp->ssl) {
    log_err("cannot create SSL object");
    return 0;
  }
#ifdef USE_WINSOCK
  comm_point_tcp_win_bio_cb(cp, cp->ssl);
#endif
  cp->ssl_shake_state = comm_ssl_shake_write;
  /* https verification */
#ifdef HAVE_SSL
  if(outnet->tls_use_sni) {
    (void)SSL_set_tlsext_host_name(cp->ssl, host);
  }
#endif
#ifdef HAVE_SSL_SET1_HOST
  if((SSL_CTX_get_verify_mode(outnet->sslctx)&SSL_VERIFY_PEER)) {
    /* because we set SSL_VERIFY_PEER, in netevent in
     * ssl_handshake, it'll check if the certificate
     * verification has succeeded */
    /* SSL_VERIFY_PEER is set on the sslctx */
    /* and the certificates to verify with are loaded into
     * it with SSL_load_verify_locations or
     * SSL_CTX_set_default_verify_paths */
    /* setting the hostname makes openssl verify the
     * host name in the x509 certificate in the
     * SSL connection*/
    if(!SSL_set1_host(cp->ssl, host)) {
      log_err("SSL_set1_host failed");
      return 0;
    }
  }
#elif defined(HAVE_X509_VERIFY_PARAM_SET1_HOST)
  /* openssl 1.0.2 has this function that can be used for
   * set1_host like verification */
  if((SSL_CTX_get_verify_mode(outnet->sslctx)&SSL_VERIFY_PEER)) {
    X509_VERIFY_PARAM* param = SSL_get0_param(cp->ssl);
#  ifdef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
    X509_VERIFY_PARAM_set_hostflags(param, X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS);
#  endif
    if(!X509_VERIFY_PARAM_set1_host(param, host, strlen(host))) {
      log_err("X509_VERIFY_PARAM_set1_host failed");
      return 0;
    }
  }
#else
  (void)host;
#endif /* HAVE_SSL_SET1_HOST */
  return 1;
}

struct comm_point*
outnet_comm_point_for_tcp(struct outside_network* outnet,
  comm_point_callback_type* cb, void* cb_arg,
  struct sockaddr_storage* to_addr, socklen_t to_addrlen,
  sldns_buffer* query, int timeout, int ssl, char* host)
{
  struct comm_point* cp;
  int fd = outnet_get_tcp_fd(to_addr, to_addrlen, outnet->tcp_mss,
    outnet->ip_dscp, ssl);
  if(fd == -1) {
    return 0;
  }
  fd_set_nonblock(fd);
  if(!outnet_tcp_connect(fd, to_addr, to_addrlen)) {
    /* outnet_tcp_connect has closed fd on error for us */
    return 0;
  }
  cp = comm_point_create_tcp_out(outnet->base, 65552, cb, cb_arg);
  if(!cp) {
    log_err("malloc failure");
    close(fd);
    return 0;
  }
  cp->repinfo.remote_addrlen = to_addrlen;
  memcpy(&cp->repinfo.remote_addr, to_addr, to_addrlen);

  /* setup for SSL (if needed) */
  if(ssl) {
    if(!setup_comm_ssl(cp, outnet, fd, host)) {
      log_err("cannot setup XoT");
      comm_point_delete(cp);
      return NULL;
    }
  }

  /* set timeout on TCP connection */
  comm_point_start_listening(cp, fd, timeout);
  /* copy scratch buffer to cp->buffer */
  sldns_buffer_copy(cp->buffer, query);
  return cp;
}

/** setup the User-Agent HTTP header based on http-user-agent configuration */
static void
setup_http_user_agent(sldns_buffer* buf, struct config_file* cfg)
{
  if(cfg->hide_http_user_agent) return;
  if(cfg->http_user_agent==NULL || cfg->http_user_agent[0] == 0) {
    sldns_buffer_printf(buf, "User-Agent: %s/%s\r\n", PACKAGE_NAME,
      PACKAGE_VERSION);
  } else {
    sldns_buffer_printf(buf, "User-Agent: %s\r\n", cfg->http_user_agent);
  }
}

/** setup http request headers in buffer for sending query to destination */
static int
setup_http_request(sldns_buffer* buf, char* host, char* path,
  struct config_file* cfg)
{
  sldns_buffer_clear(buf);
  sldns_buffer_printf(buf, "GET /%s HTTP/1.1\r\n", path);
  sldns_buffer_printf(buf, "Host: %s\r\n", host);
  setup_http_user_agent(buf, cfg);
  /* We do not really do multiple queries per connection,
   * but this header setting is also not needed.
   * sldns_buffer_printf(buf, "Connection: close\r\n") */
  sldns_buffer_printf(buf, "\r\n");
  if(sldns_buffer_position(buf)+10 > sldns_buffer_capacity(buf))
    return 0; /* somehow buffer too short, but it is about 60K
    and the request is only a couple bytes long. */
  sldns_buffer_flip(buf);
  return 1;
}

struct comm_point*
outnet_comm_point_for_http(struct outside_network* outnet,
  comm_point_callback_type* cb, void* cb_arg,
  struct sockaddr_storage* to_addr, socklen_t to_addrlen, int timeout,
  int ssl, char* host, char* path, struct config_file* cfg)
{
  /* cp calls cb with err=NETEVENT_DONE when transfer is done */
  struct comm_point* cp;
  int fd = outnet_get_tcp_fd(to_addr, to_addrlen, outnet->tcp_mss,
    outnet->ip_dscp, ssl);
  if(fd == -1) {
    return 0;
  }
  fd_set_nonblock(fd);
  if(!outnet_tcp_connect(fd, to_addr, to_addrlen)) {
    /* outnet_tcp_connect has closed fd on error for us */
    return 0;
  }
  cp = comm_point_create_http_out(outnet->base, 65552, cb, cb_arg,
    outnet->udp_buff);
  if(!cp) {
    log_err("malloc failure");
    close(fd);
    return 0;
  }
  cp->repinfo.remote_addrlen = to_addrlen;
  memcpy(&cp->repinfo.remote_addr, to_addr, to_addrlen);

  /* setup for SSL (if needed) */
  if(ssl) {
    if(!setup_comm_ssl(cp, outnet, fd, host)) {
      log_err("cannot setup https");
      comm_point_delete(cp);
      return NULL;
    }
  }

  /* set timeout on TCP connection */
  comm_point_start_listening(cp, fd, timeout);

  /* setup http request in cp->buffer */
  if(!setup_http_request(cp->buffer, host, path, cfg)) {
    log_err("error setting up http request");
    comm_point_delete(cp);
    return NULL;
  }
  return cp;
}

/** get memory used by waiting tcp entry (in use or not) */
static size_t
waiting_tcp_get_mem(struct waiting_tcp* w)
{
  size_t s;
  if(!w) return 0;
  s = sizeof(*w) + w->pkt_len;
  if(w->timer)
    s += comm_timer_get_mem(w->timer);
  return s;
}

/** get memory used by port if */
static size_t
if_get_mem(struct port_if* pif)
{
  size_t s;
  int i;
  s = sizeof(*pif) +
#ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
      sizeof(int)*pif->avail_total +
#endif
    sizeof(struct port_comm*)*pif->maxout;
  for(i=0; i<pif->inuse; i++)
    s += sizeof(*pif->out[i]) + 
      comm_point_get_mem(pif->out[i]->cp);
  return s;
}

/** get memory used by waiting udp */
static size_t
waiting_udp_get_mem(struct pending* w)
{
  size_t s;
  s = sizeof(*w) + comm_timer_get_mem(w->timer) + w->pkt_len;
  return s;
}

size_t outnet_get_mem(struct outside_network* outnet)
{
  size_t i;
  int k;
  struct waiting_tcp* w;
  struct pending* u;
  struct serviced_query* sq;
  struct service_callback* sb;
  struct port_comm* pc;
  size_t s = sizeof(*outnet) + sizeof(*outnet->base) + 
    sizeof(*outnet->udp_buff) + 
    sldns_buffer_capacity(outnet->udp_buff);
  /* second buffer is not ours */
  for(pc = outnet->unused_fds; pc; pc = pc->next) {
    s += sizeof(*pc) + comm_point_get_mem(pc->cp);
  }
  for(k=0; k<outnet->num_ip4; k++)
    s += if_get_mem(&outnet->ip4_ifs[k]);
  for(k=0; k<outnet->num_ip6; k++)
    s += if_get_mem(&outnet->ip6_ifs[k]);
  for(u=outnet->udp_wait_first; u; u=u->next_waiting)
    s += waiting_udp_get_mem(u);
  
  s += sizeof(struct pending_tcp*)*outnet->num_tcp;
  for(i=0; i<outnet->num_tcp; i++) {
    s += sizeof(struct pending_tcp);
    s += comm_point_get_mem(outnet->tcp_conns[i]->c);
    if(outnet->tcp_conns[i]->query)
      s += waiting_tcp_get_mem(outnet->tcp_conns[i]->query);
  }
  for(w=outnet->tcp_wait_first; w; w = w->next_waiting)
    s += waiting_tcp_get_mem(w);
  s += sizeof(*outnet->pending);
  s += (sizeof(struct pending) + comm_timer_get_mem(NULL)) * 
    outnet->pending->count;
  s += sizeof(*outnet->serviced);
  s += outnet->svcd_overhead;
  RBTREE_FOR(sq, struct serviced_query*, outnet->serviced) {
    s += sizeof(*sq) + sq->qbuflen;
    for(sb = sq->cblist; sb; sb = sb->next)
      s += sizeof(*sb);
  }
  return s;
}

size_t 
serviced_get_mem(struct serviced_query* sq)
{
  struct service_callback* sb;
  size_t s;
  s = sizeof(*sq) + sq->qbuflen;
  for(sb = sq->cblist; sb; sb = sb->next)
    s += sizeof(*sb);
  if(sq->status == serviced_query_UDP_EDNS ||
    sq->status == serviced_query_UDP ||
    sq->status == serviced_query_UDP_EDNS_FRAG ||
    sq->status == serviced_query_UDP_EDNS_fallback) {
    s += sizeof(struct pending);
    s += comm_timer_get_mem(NULL);
  } else {
    /* does not have size of the pkt pointer */
    /* always has a timer except on malloc failures */

    /* these sizes are part of the main outside network mem */
    /*
    s += sizeof(struct waiting_tcp);
    s += comm_timer_get_mem(NULL);
    */
  }
  return s;
}


Coverage Report

Created: 2025-08-28 06:16