Fix one case of last checkin.

[glibc.git] / sysdeps / posix / getaddrinfo.c

/* The Inner Net License, Version 2.00

  The author(s) grant permission for redistribution and use in source and
binary forms, with or without modification, of the software and documentation
provided that the following conditions are met:

0. If you receive a version of the software that is specifically labelled
   as not being for redistribution (check the version message and/or README),
   you are not permitted to redistribute that version of the software in any
   way or form.
1. All terms of the all other applicable copyrights and licenses must be
   followed.
2. Redistributions of source code must retain the authors' copyright
   notice(s), this list of conditions, and the following disclaimer.
3. Redistributions in binary form must reproduce the authors' copyright
   notice(s), this list of conditions, and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
4. [The copyright holder has authorized the removal of this clause.]
5. Neither the name(s) of the author(s) 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 ITS AUTHORS 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 AUTHORS 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.

  If these license terms cause you a real problem, contact the author.  */

/* This software is Copyright 1996 by Craig Metz, All Rights Reserved.  */

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <ifaddrs.h>
#include <netdb.h>
#include <nss.h>
#include <resolv.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/utsname.h>
#include <unistd.h>
#include <nsswitch.h>
#include <bits/libc-lock.h>
#include <not-cancel.h>
#include <nscd/nscd-client.h>
#include <nscd/nscd_proto.h>
#include <resolv/res_hconf.h>

#ifdef HAVE_LIBIDN
extern int __idna_to_ascii_lz (const char *input, char **output, int flags);
extern int __idna_to_unicode_lzlz (const char *input, char **output,
                                   int flags);
# include <libidn/idna.h>
#endif

#define GAIH_OKIFUNSPEC 0x0100
#define GAIH_EAI        ~(GAIH_OKIFUNSPEC)

#ifndef UNIX_PATH_MAX
# define UNIX_PATH_MAX  108
#endif

struct gaih_service
  {
    const char *name;
    int num;
  };

struct gaih_servtuple
  {
    struct gaih_servtuple *next;
    int socktype;
    int protocol;
    int port;
  };

static const struct gaih_servtuple nullserv;


struct gaih_typeproto
  {
    int socktype;
    int protocol;
    uint8_t protoflag;
    bool defaultflag;
    char name[8];
  };

/* Values for `protoflag'.  */
#define GAI_PROTO_NOSERVICE     1
#define GAI_PROTO_PROTOANY      2

static const struct gaih_typeproto gaih_inet_typeproto[] =
{
  { 0, 0, 0, false, "" },
  { SOCK_STREAM, IPPROTO_TCP, 0, true, "tcp" },
  { SOCK_DGRAM, IPPROTO_UDP, 0, true, "udp" },
#if defined SOCK_DCCP && defined IPPROTO_DCCP
  { SOCK_DCCP, IPPROTO_DCCP, 0, false, "dccp" },
#endif
#ifdef IPPROTO_UDPLITE
  { SOCK_DGRAM, IPPROTO_UDPLITE, 0, false, "udplite" },
#endif
#ifdef IPPROTO_SCTP
  { SOCK_STREAM, IPPROTO_SCTP, 0, false, "sctp" },
  { SOCK_SEQPACKET, IPPROTO_SCTP, 0, false, "sctp" },
#endif
  { SOCK_RAW, 0, GAI_PROTO_PROTOANY|GAI_PROTO_NOSERVICE, true, "raw" },
  { 0, 0, 0, false, "" }
};

struct gaih
  {
    int family;
    int (*gaih)(const char *name, const struct gaih_service *service,
                const struct addrinfo *req, struct addrinfo **pai,
                unsigned int *naddrs);
  };

static const struct addrinfo default_hints =
  {
    .ai_flags = AI_DEFAULT,
    .ai_family = PF_UNSPEC,
    .ai_socktype = 0,
    .ai_protocol = 0,
    .ai_addrlen = 0,
    .ai_addr = NULL,
    .ai_canonname = NULL,
    .ai_next = NULL
  };


static int
gaih_inet_serv (const char *servicename, const struct gaih_typeproto *tp,
                const struct addrinfo *req, struct gaih_servtuple *st)
{
  struct servent *s;
  size_t tmpbuflen = 1024;
  struct servent ts;
  char *tmpbuf;
  int r;

  do
    {
      tmpbuf = __alloca (tmpbuflen);

      r = __getservbyname_r (servicename, tp->name, &ts, tmpbuf, tmpbuflen,
                             &s);
      if (r != 0 || s == NULL)
        {
          if (r == ERANGE)
            tmpbuflen *= 2;
          else
            return GAIH_OKIFUNSPEC | -EAI_SERVICE;
        }
    }
  while (r);

  st->next = NULL;
  st->socktype = tp->socktype;
  st->protocol = ((tp->protoflag & GAI_PROTO_PROTOANY)
                  ? req->ai_protocol : tp->protocol);
  st->port = s->s_port;

  return 0;
}

#define gethosts(_family, _type) \
 {                                                                            \
  int i;                                                                      \
  int herrno;                                                                 \
  struct hostent th;                                                          \
  struct hostent *h;                                                          \
  char *localcanon = NULL;                                                    \
  no_data = 0;                                                                \
  while (1) {                                                                 \
    rc = 0;                                                                   \
    status = DL_CALL_FCT (fct, (name, _family, &th, tmpbuf, tmpbuflen,        \
                                &rc, &herrno, NULL, &localcanon));            \
    if (rc != ERANGE || herrno != NETDB_INTERNAL)                             \
      break;                                                                  \
    tmpbuf = extend_alloca (tmpbuf, tmpbuflen, 2 * tmpbuflen);                \
  }                                                                           \
  if (status == NSS_STATUS_SUCCESS && rc == 0)                                \
    h = &th;                                                                  \
  else                                                                        \
    h = NULL;                                                                 \
  if (rc != 0)                                                                \
    {                                                                         \
      if (herrno == NETDB_INTERNAL)                                           \
        {                                                                     \
          __set_h_errno (herrno);                                             \
          _res.options = old_res_options;                                     \
          return -EAI_SYSTEM;                                                 \
        }                                                                     \
      if (herrno == TRY_AGAIN)                                                \
        no_data = EAI_AGAIN;                                                  \
      else                                                                    \
        no_data = herrno == NO_DATA;                                          \
    }                                                                         \
  else if (h != NULL)                                                         \
    {                                                                         \
      for (i = 0; h->h_addr_list[i]; i++)                                     \
        {                                                                     \
          if (*pat == NULL)                                                   \
            {                                                                 \
              *pat = __alloca (sizeof (struct gaih_addrtuple));               \
              (*pat)->scopeid = 0;                                            \
            }                                                                 \
          uint32_t *addr = (*pat)->addr;                                      \
          (*pat)->next = NULL;                                                \
          (*pat)->name = i == 0 ? strdupa (h->h_name) : NULL;                 \
          if (_family == AF_INET && req->ai_family == AF_INET6)               \
            {                                                                 \
              (*pat)->family = AF_INET6;                                      \
              addr[3] = *(uint32_t *) h->h_addr_list[i];                      \
              addr[2] = htonl (0xffff);                                       \
              addr[1] = 0;                                                    \
              addr[0] = 0;                                                    \
            }                                                                 \
          else                                                                \
            {                                                                 \
              (*pat)->family = _family;                                       \
              memcpy (addr, h->h_addr_list[i], sizeof(_type));                \
            }                                                                 \
          pat = &((*pat)->next);                                              \
        }                                                                     \
                                                                              \
      if (localcanon != NULL && canon == NULL)                                \
        canon = strdupa (localcanon);                                         \
                                                                              \
      if (_family == AF_INET6 && i > 0)                                       \
        got_ipv6 = true;                                                      \
    }                                                                         \
 }


typedef enum nss_status (*nss_gethostbyname4_r)
  (const char *name, struct gaih_addrtuple **pat,
   char *buffer, size_t buflen, int *errnop,
   int *h_errnop, int32_t *ttlp);
typedef enum nss_status (*nss_gethostbyname3_r)
  (const char *name, int af, struct hostent *host,
   char *buffer, size_t buflen, int *errnop,
   int *h_errnop, int32_t *ttlp, char **canonp);
typedef enum nss_status (*nss_getcanonname_r)
  (const char *name, char *buffer, size_t buflen, char **result,
   int *errnop, int *h_errnop);
extern service_user *__nss_hosts_database attribute_hidden;


static int
gaih_inet (const char *name, const struct gaih_service *service,
           const struct addrinfo *req, struct addrinfo **pai,
           unsigned int *naddrs)
{
  const struct gaih_typeproto *tp = gaih_inet_typeproto;
  struct gaih_servtuple *st = (struct gaih_servtuple *) &nullserv;
  struct gaih_addrtuple *at = NULL;
  int rc;
  bool got_ipv6 = false;
  const char *canon = NULL;
  const char *orig_name = name;

  if (req->ai_protocol || req->ai_socktype)
    {
      ++tp;

      while (tp->name[0]
             && ((req->ai_socktype != 0 && req->ai_socktype != tp->socktype)
                 || (req->ai_protocol != 0
                     && !(tp->protoflag & GAI_PROTO_PROTOANY)
                     && req->ai_protocol != tp->protocol)))
        ++tp;

      if (! tp->name[0])
        {
          if (req->ai_socktype)
            return GAIH_OKIFUNSPEC | -EAI_SOCKTYPE;
          else
            return GAIH_OKIFUNSPEC | -EAI_SERVICE;
        }
    }

  int port = 0;
  if (service != NULL)
    {
      if ((tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
        return GAIH_OKIFUNSPEC | -EAI_SERVICE;

      if (service->num < 0)
        {
          if (tp->name[0])
            {
              st = (struct gaih_servtuple *)
                __alloca (sizeof (struct gaih_servtuple));

              if ((rc = gaih_inet_serv (service->name, tp, req, st)))
                return rc;
            }
          else
            {
              struct gaih_servtuple **pst = &st;
              for (tp++; tp->name[0]; tp++)
                {
                  struct gaih_servtuple *newp;

                  if ((tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
                    continue;

                  if (req->ai_socktype != 0
                      && req->ai_socktype != tp->socktype)
                    continue;
                  if (req->ai_protocol != 0
                      && !(tp->protoflag & GAI_PROTO_PROTOANY)
                      && req->ai_protocol != tp->protocol)
                    continue;

                  newp = (struct gaih_servtuple *)
                    __alloca (sizeof (struct gaih_servtuple));

                  if ((rc = gaih_inet_serv (service->name, tp, req, newp)))
                    {
                      if (rc & GAIH_OKIFUNSPEC)
                        continue;
                      return rc;
                    }

                  *pst = newp;
                  pst = &(newp->next);
                }
              if (st == (struct gaih_servtuple *) &nullserv)
                return GAIH_OKIFUNSPEC | -EAI_SERVICE;
            }
        }
      else
        {
          port = htons (service->num);
          goto got_port;
        }
    }
  else
    {
    got_port:

      if (req->ai_socktype || req->ai_protocol)
        {
          st = __alloca (sizeof (struct gaih_servtuple));
          st->next = NULL;
          st->socktype = tp->socktype;
          st->protocol = ((tp->protoflag & GAI_PROTO_PROTOANY)
                          ? req->ai_protocol : tp->protocol);
          st->port = port;
        }
      else
        {
          /* Neither socket type nor protocol is set.  Return all socket types
             we know about.  */
          struct gaih_servtuple **lastp = &st;
          for (++tp; tp->name[0]; ++tp)
            if (tp->defaultflag)
              {
                struct gaih_servtuple *newp;

                newp = __alloca (sizeof (struct gaih_servtuple));
                newp->next = NULL;
                newp->socktype = tp->socktype;
                newp->protocol = tp->protocol;
                newp->port = port;

                *lastp = newp;
                lastp = &newp->next;
              }
        }
    }

  if (name != NULL)
    {
      at = __alloca (sizeof (struct gaih_addrtuple));

      at->family = AF_UNSPEC;
      at->scopeid = 0;
      at->next = NULL;

#ifdef HAVE_LIBIDN
      if (req->ai_flags & AI_IDN)
        {
          int idn_flags = 0;
          if (req->ai_flags & AI_IDN_ALLOW_UNASSIGNED)
            idn_flags |= IDNA_ALLOW_UNASSIGNED;
          if (req->ai_flags & AI_IDN_USE_STD3_ASCII_RULES)
            idn_flags |= IDNA_USE_STD3_ASCII_RULES;

          char *p = NULL;
          rc = __idna_to_ascii_lz (name, &p, idn_flags);
          if (rc != IDNA_SUCCESS)
            {
              if (rc == IDNA_MALLOC_ERROR)
                return -EAI_MEMORY;
              if (rc == IDNA_DLOPEN_ERROR)
                return -EAI_SYSTEM;
              return -EAI_IDN_ENCODE;
            }
          /* In case the output string is the same as the input string
             no new string has been allocated.  */
          if (p != name)
            {
              name = strdupa (p);
              free (p);
            }
        }
#endif

      if (__inet_aton (name, (struct in_addr *) at->addr) != 0)
        {
          if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET)
            at->family = AF_INET;
          else if (req->ai_family == AF_INET6 && (req->ai_flags & AI_V4MAPPED))
            {
              at->addr[3] = at->addr[0];
              at->addr[2] = htonl (0xffff);
              at->addr[1] = 0;
              at->addr[0] = 0;
              at->family = AF_INET6;
            }
          else
            return -EAI_ADDRFAMILY;

          if (req->ai_flags & AI_CANONNAME)
            canon = name;
        }
      else if (at->family == AF_UNSPEC)
        {
          char *namebuf = (char *) name;
          char *scope_delim = strchr (name, SCOPE_DELIMITER);

          if (__builtin_expect (scope_delim != NULL, 0))
            {
              namebuf = alloca (scope_delim - name + 1);
              *((char *) __mempcpy (namebuf, name, scope_delim - name)) = '\0';
            }

          if (inet_pton (AF_INET6, namebuf, at->addr) > 0)
            {
              if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET6)
                at->family = AF_INET6;
              else if (req->ai_family == AF_INET
                       && IN6_IS_ADDR_V4MAPPED (at->addr))
                {
                  at->addr[0] = at->addr[3];
                  at->family = AF_INET;
                }
              else
                return -EAI_ADDRFAMILY;

              if (scope_delim != NULL)
                {
                  int try_numericscope = 0;
                  if (IN6_IS_ADDR_LINKLOCAL (at->addr)
                      || IN6_IS_ADDR_MC_LINKLOCAL (at->addr))
                    {
                      at->scopeid = if_nametoindex (scope_delim + 1);
                      if (at->scopeid == 0)
                        try_numericscope = 1;
                    }
                  else
                    try_numericscope = 1;

                  if (try_numericscope != 0)
                    {
                      char *end;
                      assert (sizeof (uint32_t) <= sizeof (unsigned long));
                      at->scopeid = (uint32_t) strtoul (scope_delim + 1, &end,
                                                        10);
                      if (*end != '\0')
                        return GAIH_OKIFUNSPEC | -EAI_NONAME;
                    }
                }

              if (req->ai_flags & AI_CANONNAME)
                canon = name;
            }
        }

      if (at->family == AF_UNSPEC && (req->ai_flags & AI_NUMERICHOST) == 0)
        {
          struct gaih_addrtuple **pat = &at;
          int no_data = 0;
          int no_inet6_data = 0;
          service_user *nip = NULL;
          enum nss_status inet6_status = NSS_STATUS_UNAVAIL;
          enum nss_status status = NSS_STATUS_UNAVAIL;
          int no_more;
          int old_res_options;

          /* If we do not have to look for IPv4 and IPv6 together, use
             the simple, old functions.  */
          if (req->ai_family == AF_INET
              || (req->ai_family == AF_INET6
                  && ((req->ai_flags & AI_V4MAPPED) == 0
                      || (req->ai_flags & AI_ALL) == 0)))
            {
              int family = req->ai_family;
              size_t tmpbuflen = 512;
              char *tmpbuf = alloca (tmpbuflen);
              int rc;
              struct hostent th;
              struct hostent *h;
              int herrno;

            simple_again:
              while (1)
                {
                  rc = __gethostbyname2_r (name, family, &th, tmpbuf,
                                           tmpbuflen, &h, &herrno);
                  if (rc != ERANGE || herrno != NETDB_INTERNAL)
                    break;
                  tmpbuf = extend_alloca (tmpbuf, tmpbuflen, 2 * tmpbuflen);
                }

              if (rc == 0)
                {
                  if (h == NULL)
                    {
                      if (req->ai_family == AF_INET6
                          && (req->ai_flags & AI_V4MAPPED)
                          && family == AF_INET6)
                        {
                          /* Try again, this time looking for IPv4
                             addresses.  */
                          family = AF_INET;
                          goto simple_again;
                        }
                    }
                  else
                    {
                      /* We found data, now convert it into the list.  */
                      for (int i = 0; h->h_addr_list[i]; ++i)
                        {
                          if (*pat == NULL)
                            {
                              *pat = __alloca (sizeof (struct gaih_addrtuple));
                              (*pat)->scopeid = 0;
                            }
                          (*pat)->next = NULL;
                          (*pat)->family = req->ai_family;
                          if (family == req->ai_family)
                            memcpy ((*pat)->addr, h->h_addr_list[i],
                                    h->h_length);
                          else
                            {
                              uint32_t *addr = (uint32_t *) (*pat)->addr;
                              addr[3] = *(uint32_t *) h->h_addr_list[i];
                              addr[2] = htonl (0xffff);
                              addr[1] = 0;
                              addr[0] = 0;
                            }
                          pat = &((*pat)->next);
                        }
                    }
                }
              else
                {
                  if (herrno == NETDB_INTERNAL)
                    {
                      __set_h_errno (herrno);
                      return -EAI_SYSTEM;
                    }
                  if (herrno == TRY_AGAIN)
                    {
                      return -EAI_AGAIN;
                    }
                  /* We made requests but they turned out no data.
                     The name is known, though.  */
                  return GAIH_OKIFUNSPEC | -EAI_NODATA;
                }

              goto process_list;
            }

#ifdef USE_NSCD
          if (__nss_not_use_nscd_hosts > 0
              && ++__nss_not_use_nscd_hosts > NSS_NSCD_RETRY)
            __nss_not_use_nscd_hosts = 0;

          if (!__nss_not_use_nscd_hosts)
            {
              /* Try to use nscd.  */
              struct nscd_ai_result *air = NULL;
              int herrno;
              int err = __nscd_getai (name, &air, &herrno);
              if (air != NULL)
                {
                  /* Transform into gaih_addrtuple list.  */
                  bool added_canon = (req->ai_flags & AI_CANONNAME) == 0;
                  char *addrs = air->addrs;

                  for (int i = 0; i < air->naddrs; ++i)
                    {
                      socklen_t size = (air->family[i] == AF_INET
                                        ? INADDRSZ : IN6ADDRSZ);
                      if (*pat == NULL)
                        {
                          *pat = __alloca (sizeof (struct gaih_addrtuple));
                          (*pat)->scopeid = 0;
                        }
                      uint32_t *pataddr = (*pat)->addr;
                      (*pat)->next = NULL;
                      if (added_canon || air->canon == NULL)
                        (*pat)->name = NULL;
                      else
                        canon = (*pat)->name = strdupa (air->canon);

                      if (air->family[i] == AF_INET
                          && req->ai_family == AF_INET6
                          && (req->ai_flags & AI_V4MAPPED))
                        {
                          (*pat)->family = AF_INET6;
                          pataddr[3] = *(uint32_t *) addrs;
                          pataddr[2] = htonl (0xffff);
                          pataddr[1] = 0;
                          pataddr[0] = 0;
                          pat = &((*pat)->next);
                          added_canon = true;
                        }
                      else if (req->ai_family == AF_UNSPEC
                               || air->family[i] == req->ai_family)
                        {
                          (*pat)->family = air->family[i];
                          memcpy (pataddr, addrs, size);
                          pat = &((*pat)->next);
                          added_canon = true;
                          if (air->family[i] == AF_INET6)
                            got_ipv6 = true;
                        }
                      addrs += size;
                    }

                  free (air);

                  if (at->family == AF_UNSPEC)
                    return GAIH_OKIFUNSPEC | -EAI_NONAME;

                  goto process_list;
                }
              else if (err == 0)
                /* The database contains a negative entry.  */
                return 0;
              else if (__nss_not_use_nscd_hosts == 0)
                {
                  if (herrno == NETDB_INTERNAL && errno == ENOMEM)
                    return -EAI_MEMORY;
                  if (herrno == TRY_AGAIN)
                    return -EAI_AGAIN;
                  return -EAI_SYSTEM;
                }
            }
#endif

          if (__nss_hosts_database != NULL)
            {
              no_more = 0;
              nip = __nss_hosts_database;
            }
          else
            no_more = __nss_database_lookup ("hosts", NULL,
                                             "dns [!UNAVAIL=return] files",
                                             &nip);

          /* Initialize configurations.  */
          if (__builtin_expect (!_res_hconf.initialized, 0))
            _res_hconf_init ();
          if (__res_maybe_init (&_res, 0) == -1)
            no_more = 1;

          /* If we are looking for both IPv4 and IPv6 address we don't
             want the lookup functions to automatically promote IPv4
             addresses to IPv6 addresses.  Currently this is decided
             by setting the RES_USE_INET6 bit in _res.options.  */
          old_res_options = _res.options;
          _res.options &= ~RES_USE_INET6;

          size_t tmpbuflen = 1024;
          char *tmpbuf = alloca (tmpbuflen);

          while (!no_more)
            {
              no_data = 0;
              nss_gethostbyname4_r fct4
                = __nss_lookup_function (nip, "gethostbyname4_r");
              if (fct4 != NULL)
                {
                  int herrno;

                  while (1)
                    {
                      rc = 0;
                      status = DL_CALL_FCT (fct4, (name, pat, tmpbuf,
                                                   tmpbuflen, &rc, &herrno,
                                                   NULL));
                      if (status == NSS_STATUS_SUCCESS)
                        break;
                      if (status != NSS_STATUS_TRYAGAIN
                          || rc != ERANGE || herrno != NETDB_INTERNAL)
                        {
                          if (status == NSS_STATUS_TRYAGAIN
                              && herrno == TRY_AGAIN)
                            no_data = EAI_AGAIN;
                          else
                            no_data = herrno == NO_DATA;
                          break;
                        }
                      tmpbuf = extend_alloca (tmpbuf,
                                              tmpbuflen, 2 * tmpbuflen);
                    }

                  no_inet6_data = no_data;

                  if (status == NSS_STATUS_SUCCESS)
                    {
                      if ((req->ai_flags & AI_CANONNAME) != 0 && canon == NULL)
                        canon = (*pat)->name;

                      while (*pat != NULL)
                        pat = &((*pat)->next);
                    }
                }
              else
                {
                  nss_gethostbyname3_r fct = NULL;
                  if (req->ai_flags & AI_CANONNAME)
                    /* No need to use this function if we do not look for
                       the canonical name.  The function does not exist in
                       all NSS modules and therefore the lookup would
                       often fail.  */
                    fct = __nss_lookup_function (nip, "gethostbyname3_r");
                  if (fct == NULL)
                    /* We are cheating here.  The gethostbyname2_r
                       function does not have the same interface as
                       gethostbyname3_r but the extra arguments the
                       latter takes are added at the end.  So the
                       gethostbyname2_r code will just ignore them.  */
                    fct = __nss_lookup_function (nip, "gethostbyname2_r");

                  if (fct != NULL)
                    {
                      if (req->ai_family == AF_INET6
                          || req->ai_family == AF_UNSPEC)
                        {
                          gethosts (AF_INET6, struct in6_addr);
                          no_inet6_data = no_data;
                          inet6_status = status;
                        }
                      if (req->ai_family == AF_INET
                          || req->ai_family == AF_UNSPEC
                          || (req->ai_family == AF_INET6
                              && (req->ai_flags & AI_V4MAPPED)
                              /* Avoid generating the mapped addresses if we
                                 know we are not going to need them.  */
                              && ((req->ai_flags & AI_ALL) || !got_ipv6)))
                        {
                          gethosts (AF_INET, struct in_addr);

                          if (req->ai_family == AF_INET)
                            {
                              no_inet6_data = no_data;
                              inet6_status = status;
                            }
                        }

                      /* If we found one address for AF_INET or AF_INET6,
                         don't continue the search.  */
                      if (inet6_status == NSS_STATUS_SUCCESS
                          || status == NSS_STATUS_SUCCESS)
                        {
                          if ((req->ai_flags & AI_CANONNAME) != 0
                              && canon == NULL)
                            {
                              /* If we need the canonical name, get it
                                 from the same service as the result.  */
                              nss_getcanonname_r cfct;
                              int herrno;

                              cfct = __nss_lookup_function (nip,
                                                            "getcanonname_r");
                              if (cfct != NULL)
                                {
                                  const size_t max_fqdn_len = 256;
                                  char *buf = alloca (max_fqdn_len);
                                  char *s;

                                  if (DL_CALL_FCT (cfct, (at->name ?: name,
                                                          buf, max_fqdn_len,
                                                          &s, &rc, &herrno))
                                      == NSS_STATUS_SUCCESS)
                                    canon = s;
                                  else
                                    /* Set to name now to avoid using
                                       gethostbyaddr.  */
                                    canon = name;
                                }
                            }
                          status = NSS_STATUS_SUCCESS;
                        }
                      else
                        {
                          /* We can have different states for AF_INET and
                             AF_INET6.  Try to find a useful one for both.  */
                          if (inet6_status == NSS_STATUS_TRYAGAIN)
                            status = NSS_STATUS_TRYAGAIN;
                          else if (status == NSS_STATUS_UNAVAIL
                                   && inet6_status != NSS_STATUS_UNAVAIL)
                            status = inet6_status;
                        }
                    }
                  else
                    status = NSS_STATUS_UNAVAIL;
                }

              if (nss_next_action (nip, status) == NSS_ACTION_RETURN)
                break;

              if (nip->next == NULL)
                no_more = -1;
              else
                nip = nip->next;
            }

          _res.options = old_res_options;

          if (no_data != 0 && no_inet6_data != 0)
            {
              /* If both requests timed out report this.  */
              if (no_data == EAI_AGAIN && no_inet6_data == EAI_AGAIN)
                return -EAI_AGAIN;

              /* We made requests but they turned out no data.  The name
                 is known, though.  */
              return GAIH_OKIFUNSPEC | -EAI_NODATA;
            }
        }

    process_list:
      if (at->family == AF_UNSPEC)
        return GAIH_OKIFUNSPEC | -EAI_NONAME;
    }
  else
    {
      struct gaih_addrtuple *atr;
      atr = at = __alloca (sizeof (struct gaih_addrtuple));
      memset (at, '\0', sizeof (struct gaih_addrtuple));

      if (req->ai_family == AF_UNSPEC)
        {
          at->next = __alloca (sizeof (struct gaih_addrtuple));
          memset (at->next, '\0', sizeof (struct gaih_addrtuple));
        }

      if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET6)
        {
          at->family = AF_INET6;
          if ((req->ai_flags & AI_PASSIVE) == 0)
            memcpy (at->addr, &in6addr_loopback, sizeof (struct in6_addr));
          atr = at->next;
        }

      if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET)
        {
          atr->family = AF_INET;
          if ((req->ai_flags & AI_PASSIVE) == 0)
            atr->addr[0] = htonl (INADDR_LOOPBACK);
        }
    }

  {
    struct gaih_servtuple *st2;
    struct gaih_addrtuple *at2 = at;
    size_t socklen;
    sa_family_t family;

    /*
      buffer is the size of an unformatted IPv6 address in printable format.
     */
    while (at2 != NULL)
      {
        /* Only the first entry gets the canonical name.  */
        if (at2 == at && (req->ai_flags & AI_CANONNAME) != 0)
          {
            if (canon == NULL)
              {
                struct hostent *h = NULL;
                int herrno;
                struct hostent th;
                size_t tmpbuflen = 512;
                char *tmpbuf = NULL;

                do
                  {
                    tmpbuf = extend_alloca (tmpbuf, tmpbuflen, tmpbuflen * 2);
                    rc = __gethostbyaddr_r (at2->addr,
                                            ((at2->family == AF_INET6)
                                             ? sizeof (struct in6_addr)
                                             : sizeof (struct in_addr)),
                                            at2->family, &th, tmpbuf,
                                            tmpbuflen, &h, &herrno);
                  }
                while (rc == ERANGE && herrno == NETDB_INTERNAL);

                if (rc != 0 && herrno == NETDB_INTERNAL)
                  {
                    __set_h_errno (herrno);
                    return -EAI_SYSTEM;
                  }

                if (h != NULL)
                  canon = h->h_name;
                else
                  {
                    assert (orig_name != NULL);
                    /* If the canonical name cannot be determined, use
                       the passed in string.  */
                    canon = orig_name;
                  }
              }

#ifdef HAVE_LIBIDN
            if (req->ai_flags & AI_CANONIDN)
              {
                int idn_flags = 0;
                if (req->ai_flags & AI_IDN_ALLOW_UNASSIGNED)
                  idn_flags |= IDNA_ALLOW_UNASSIGNED;
                if (req->ai_flags & AI_IDN_USE_STD3_ASCII_RULES)
                  idn_flags |= IDNA_USE_STD3_ASCII_RULES;

                char *out;
                int rc = __idna_to_unicode_lzlz (canon, &out, idn_flags);
                if (rc != IDNA_SUCCESS)
                  {
                    if (rc == IDNA_MALLOC_ERROR)
                      return -EAI_MEMORY;
                    if (rc == IDNA_DLOPEN_ERROR)
                      return -EAI_SYSTEM;
                    return -EAI_IDN_ENCODE;
                  }
                /* In case the output string is the same as the input
                   string no new string has been allocated and we
                   make a copy.  */
                if (out == canon)
                  goto make_copy;
              }
            else
#endif
              {
#ifdef HAVE_LIBIDN
              make_copy:
#endif
                canon = strdup (canon);
                if (canon == NULL)
                  return -EAI_MEMORY;
              }
          }

        family = at2->family;
        if (family == AF_INET6)
          {
            socklen = sizeof (struct sockaddr_in6);

            /* If we looked up IPv4 mapped address discard them here if
               the caller isn't interested in all address and we have
               found at least one IPv6 address.  */
            if (got_ipv6
                && (req->ai_flags & (AI_V4MAPPED|AI_ALL)) == AI_V4MAPPED
                && IN6_IS_ADDR_V4MAPPED (at2->addr))
              goto ignore;
          }
        else
          socklen = sizeof (struct sockaddr_in);

        for (st2 = st; st2 != NULL; st2 = st2->next)
          {
            struct addrinfo *ai;
            ai = *pai = malloc (sizeof (struct addrinfo) + socklen);
            if (ai == NULL)
              {
                free ((char *) canon);
                return -EAI_MEMORY;
              }

            ai->ai_flags = req->ai_flags;
            ai->ai_family = family;
            ai->ai_socktype = st2->socktype;
            ai->ai_protocol = st2->protocol;
            ai->ai_addrlen = socklen;
            ai->ai_addr = (void *) (ai + 1);

            /* We only add the canonical name once.  */
            ai->ai_canonname = (char *) canon;
            canon = NULL;

#ifdef _HAVE_SA_LEN
            ai->ai_addr->sa_len = socklen;
#endif /* _HAVE_SA_LEN */
            ai->ai_addr->sa_family = family;

            /* In case of an allocation error the list must be NULL
               terminated.  */
            ai->ai_next = NULL;

            if (family == AF_INET6)
              {
                struct sockaddr_in6 *sin6p =
                  (struct sockaddr_in6 *) ai->ai_addr;

                sin6p->sin6_port = st2->port;
                sin6p->sin6_flowinfo = 0;
                memcpy (&sin6p->sin6_addr,
                        at2->addr, sizeof (struct in6_addr));
                sin6p->sin6_scope_id = at2->scopeid;
              }
            else
              {
                struct sockaddr_in *sinp =
                  (struct sockaddr_in *) ai->ai_addr;
                sinp->sin_port = st2->port;
                memcpy (&sinp->sin_addr,
                        at2->addr, sizeof (struct in_addr));
                memset (sinp->sin_zero, '\0', sizeof (sinp->sin_zero));
              }

            pai = &(ai->ai_next);
          }

        ++*naddrs;

      ignore:
        at2 = at2->next;
      }
  }
  return 0;
}


struct sort_result
{
  struct addrinfo *dest_addr;
  /* Using sockaddr_storage is for now overkill.  We only support IPv4
     and IPv6 so far.  If this changes at some point we can adjust the
     type here.  */
  struct sockaddr_in6 source_addr;
  uint8_t source_addr_len;
  bool got_source_addr;
  uint8_t source_addr_flags;
  uint8_t prefixlen;
  uint32_t index;
  int32_t native;
};

struct sort_result_combo
{
  struct sort_result *results;
  int nresults;
};


#if __BYTE_ORDER == __BIG_ENDIAN
# define htonl_c(n) n
#else
# define htonl_c(n) __bswap_constant_32 (n)
#endif

static const struct scopeentry
{
  union
  {
    char addr[4];
    uint32_t addr32;
  };
  uint32_t netmask;
  int32_t scope;
} default_scopes[] =
  {
    /* Link-local addresses: scope 2.  */
    { { { 169, 254, 0, 0 } }, htonl_c (0xffff0000), 2 },
    { { { 127, 0, 0, 0 } }, htonl_c (0xff000000), 2 },
    /* Site-local addresses: scope 5.  */
    { { { 10, 0, 0, 0 } }, htonl_c (0xff000000), 5 },
    { { { 172, 16, 0, 0 } }, htonl_c (0xfff00000), 5 },
    { { { 192, 168, 0, 0 } }, htonl_c (0xffff0000), 5 },
    /* Default: scope 14.  */
    { { { 0, 0, 0, 0 } }, htonl_c (0x00000000), 14 }
  };

/* The label table.  */
static const struct scopeentry *scopes;


static int
get_scope (const struct sockaddr_in6 *in6)
{
  int scope;
  if (in6->sin6_family == PF_INET6)
    {
      if (! IN6_IS_ADDR_MULTICAST (&in6->sin6_addr))
        {
          if (IN6_IS_ADDR_LINKLOCAL (&in6->sin6_addr)
              /* RFC 4291 2.5.3 says that the loopback address is to be
                 treated like a link-local address.  */
              || IN6_IS_ADDR_LOOPBACK (&in6->sin6_addr))
            scope = 2;
          else if (IN6_IS_ADDR_SITELOCAL (&in6->sin6_addr))
            scope = 5;
          else
            /* XXX Is this the correct default behavior?  */
            scope = 14;
        }
      else
        scope = in6->sin6_addr.s6_addr[1] & 0xf;
    }
  else if (in6->sin6_family == PF_INET)
    {
      const struct sockaddr_in *in = (const struct sockaddr_in *) in6;

      size_t cnt = 0;
      while (1)
        {
          if ((in->sin_addr.s_addr & scopes[cnt].netmask)
              == scopes[cnt].addr32)
            return scopes[cnt].scope;

          ++cnt;
        }
      /* NOTREACHED */
    }
  else
    /* XXX What is a good default?  */
    scope = 15;

  return scope;
}


struct prefixentry
{
  struct in6_addr prefix;
  unsigned int bits;
  int val;
};


/* The label table.  */
static const struct prefixentry *labels;

/* Default labels.  */
static const struct prefixentry default_labels[] =
  {
    /* See RFC 3484 for the details.  */
    { { .__in6_u
        = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } }
      }, 128, 0 },
    { { .__in6_u
        = { .__u6_addr8 = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
      }, 16, 2 },
    { { .__in6_u
        = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
      }, 96, 3 },
    { { .__in6_u
        = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 } }
      }, 96, 4 },
    /* The next two entries differ from RFC 3484.  We need to treat
       IPv6 site-local addresses special because they are never NATed,
       unlike site-locale IPv4 addresses.  If this would not happen, on
       machines which have only IPv4 and IPv6 site-local addresses, the
       sorting would prefer the IPv6 site-local addresses, causing
       unnecessary delays when trying to connect to a global IPv6 address
       through a site-local IPv6 address.  */
    { { .__in6_u
        = { .__u6_addr8 = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
      }, 10, 5 },
    { { .__in6_u
        = { .__u6_addr8 = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
      }, 7, 6 },
    /* Additional rule for Teredo tunnels.  */
    { { .__in6_u
        = { .__u6_addr8 = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
      }, 32, 7 },
    { { .__in6_u
        = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
      }, 0, 1 }
  };


/* The precedence table.  */
static const struct prefixentry *precedence;

/* The default precedences.  */
static const struct prefixentry default_precedence[] =
  {
    /* See RFC 3484 for the details.  */
    { { .__in6_u
        = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } }
      }, 128, 50 },
    { { .__in6_u
        = { .__u6_addr8 = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
      }, 16, 30 },
    { { .__in6_u
        = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
      }, 96, 20 },
    { { .__in6_u
        = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 } }
      }, 96, 10 },
    { { .__in6_u
        = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
      }, 0, 40 }
  };


static int
match_prefix (const struct sockaddr_in6 *in6,
              const struct prefixentry *list, int default_val)
{
  int idx;
  struct sockaddr_in6 in6_mem;

  if (in6->sin6_family == PF_INET)
    {
      const struct sockaddr_in *in = (const struct sockaddr_in *) in6;

      /* Construct a V4-to-6 mapped address.  */
      in6_mem.sin6_family = PF_INET6;
      in6_mem.sin6_port = in->sin_port;
      in6_mem.sin6_flowinfo = 0;
      memset (&in6_mem.sin6_addr, '\0', sizeof (in6_mem.sin6_addr));
      in6_mem.sin6_addr.s6_addr16[5] = 0xffff;
      in6_mem.sin6_addr.s6_addr32[3] = in->sin_addr.s_addr;
      in6_mem.sin6_scope_id = 0;

      in6 = &in6_mem;
    }
  else if (in6->sin6_family != PF_INET6)
    return default_val;

  for (idx = 0; ; ++idx)
    {
      unsigned int bits = list[idx].bits;
      const uint8_t *mask = list[idx].prefix.s6_addr;
      const uint8_t *val = in6->sin6_addr.s6_addr;

      while (bits >= 8)
        {
          if (*mask != *val)
            break;

          ++mask;
          ++val;
          bits -= 8;
        }

      if (bits < 8)
        {
          if ((*mask & (0xff00 >> bits)) == (*val & (0xff00 >> bits)))
            /* Match!  */
            break;
        }
    }

  return list[idx].val;
}


static int
get_label (const struct sockaddr_in6 *in6)
{
  /* XXX What is a good default value?  */
  return match_prefix (in6, labels, INT_MAX);
}


static int
get_precedence (const struct sockaddr_in6 *in6)
{
  /* XXX What is a good default value?  */
  return match_prefix (in6, precedence, 0);
}


/* Find last bit set in a word.  */
static int
fls (uint32_t a)
{
  uint32_t mask;
  int n;
  for (n = 0, mask = 1 << 31; n < 32; mask >>= 1, ++n)
    if ((a & mask) != 0)
      break;
  return n;
}


static int
rfc3484_sort (const void *p1, const void *p2, void *arg)
{
  const size_t idx1 = *(const size_t *) p1;
  const size_t idx2 = *(const size_t *) p2;
  struct sort_result_combo *src = (struct sort_result_combo *) arg;
  struct sort_result *a1 = &src->results[idx1];
  struct sort_result *a2 = &src->results[idx2];

  /* Rule 1: Avoid unusable destinations.
     We have the got_source_addr flag set if the destination is reachable.  */
  if (a1->got_source_addr && ! a2->got_source_addr)
    return -1;
  if (! a1->got_source_addr && a2->got_source_addr)
    return 1;


  /* Rule 2: Prefer matching scope.  Only interesting if both
     destination addresses are IPv6.  */
  int a1_dst_scope
    = get_scope ((struct sockaddr_in6 *) a1->dest_addr->ai_addr);

  int a2_dst_scope
    = get_scope ((struct sockaddr_in6 *) a2->dest_addr->ai_addr);

  if (a1->got_source_addr)
    {
      int a1_src_scope = get_scope (&a1->source_addr);
      int a2_src_scope = get_scope (&a2->source_addr);

      if (a1_dst_scope == a1_src_scope && a2_dst_scope != a2_src_scope)
        return -1;
      if (a1_dst_scope != a1_src_scope && a2_dst_scope == a2_src_scope)
        return 1;
    }


  /* Rule 3: Avoid deprecated addresses.  */
  if (a1->got_source_addr)
    {
      if (!(a1->source_addr_flags & in6ai_deprecated)
          && (a2->source_addr_flags & in6ai_deprecated))
        return -1;
      if ((a1->source_addr_flags & in6ai_deprecated)
          && !(a2->source_addr_flags & in6ai_deprecated))
        return 1;
    }

  /* Rule 4: Prefer home addresses.  */
  if (a1->got_source_addr)
    {
      if (!(a1->source_addr_flags & in6ai_homeaddress)
          && (a2->source_addr_flags & in6ai_homeaddress))
        return 1;
      if ((a1->source_addr_flags & in6ai_homeaddress)
          && !(a2->source_addr_flags & in6ai_homeaddress))
        return -1;
    }

  /* Rule 5: Prefer matching label.  */
  if (a1->got_source_addr)
    {
      int a1_dst_label
        = get_label ((struct sockaddr_in6 *) a1->dest_addr->ai_addr);
      int a1_src_label = get_label (&a1->source_addr);

      int a2_dst_label
        = get_label ((struct sockaddr_in6 *) a2->dest_addr->ai_addr);
      int a2_src_label = get_label (&a2->source_addr);

      if (a1_dst_label == a1_src_label && a2_dst_label != a2_src_label)
        return -1;
      if (a1_dst_label != a1_src_label && a2_dst_label == a2_src_label)
        return 1;
    }


  /* Rule 6: Prefer higher precedence.  */
  int a1_prec
    = get_precedence ((struct sockaddr_in6 *) a1->dest_addr->ai_addr);
  int a2_prec
    = get_precedence ((struct sockaddr_in6 *) a2->dest_addr->ai_addr);

  if (a1_prec > a2_prec)
    return -1;
  if (a1_prec < a2_prec)
    return 1;


  /* Rule 7: Prefer native transport.  */
  if (a1->got_source_addr)
    {
      /* The same interface index means the same interface which means
         there is no difference in transport.  This should catch many
         (most?) cases.  */
      if (a1->index != a2->index)
        {
          int a1_native = a1->native;
          int a2_native = a2->native;

          if (a1_native == -1 || a2_native == -1)
            {
              uint32_t a1_index;
              if (a1_native == -1)
                {
                  /* If we do not have the information use 'native' as
                     the default.  */
                  a1_native = 0;
                  a1_index = a1->index;
                }
              else
                a1_index = 0xffffffffu;

              uint32_t a2_index;
              if (a2_native == -1)
                {
                  /* If we do not have the information use 'native' as
                     the default.  */
                  a2_native = 0;
                  a2_index = a2->index;
                }
              else
                a2_index = 0xffffffffu;

              __check_native (a1_index, &a1_native, a2_index, &a2_native);

              /* Fill in the results in all the records.  */
              for (int i = 0; i < src->nresults; ++i)
                if (src->results[i].index == a1_index)
                  {
                    assert (src->results[i].native == -1
                            || src->results[i].native == a1_native);
                    src->results[i].native = a1_native;
                  }
                else if (src->results[i].index == a2_index)
                  {
                    assert (src->results[i].native == -1
                            || src->results[i].native == a2_native);
                    src->results[i].native = a2_native;
                  }
            }

          if (a1_native && !a2_native)
            return -1;
          if (!a1_native && a2_native)
            return 1;
        }
    }


  /* Rule 8: Prefer smaller scope.  */
  if (a1_dst_scope < a2_dst_scope)
    return -1;
  if (a1_dst_scope > a2_dst_scope)
    return 1;


  /* Rule 9: Use longest matching prefix.  */
  if (a1->got_source_addr
      && a1->dest_addr->ai_family == a2->dest_addr->ai_family)
    {
      int bit1 = 0;
      int bit2 = 0;

      if (a1->dest_addr->ai_family == PF_INET)
        {
          assert (a1->source_addr.sin6_family == PF_INET);
          assert (a2->source_addr.sin6_family == PF_INET);

          /* Outside of subnets, as defined by the network masks,
             common address prefixes for IPv4 addresses make no sense.
             So, define a non-zero value only if source and
             destination address are on the same subnet.  */
          struct sockaddr_in *in1_dst
            = (struct sockaddr_in *) a1->dest_addr->ai_addr;
          in_addr_t in1_dst_addr = ntohl (in1_dst->sin_addr.s_addr);
          struct sockaddr_in *in1_src
            = (struct sockaddr_in *) &a1->source_addr;
          in_addr_t in1_src_addr = ntohl (in1_src->sin_addr.s_addr);
          in_addr_t netmask1 = 0xffffffffu << (32 - a1->prefixlen);

          if ((in1_src_addr & netmask1) == (in1_dst_addr & netmask1))
            bit1 = fls (in1_dst_addr ^ in1_src_addr);

          struct sockaddr_in *in2_dst
            = (struct sockaddr_in *) a2->dest_addr->ai_addr;
          in_addr_t in2_dst_addr = ntohl (in2_dst->sin_addr.s_addr);
          struct sockaddr_in *in2_src
            = (struct sockaddr_in *) &a2->source_addr;
          in_addr_t in2_src_addr = ntohl (in2_src->sin_addr.s_addr);
          in_addr_t netmask2 = 0xffffffffu << (32 - a2->prefixlen);

          if ((in2_src_addr & netmask2) == (in2_dst_addr & netmask2))
            bit2 = fls (in2_dst_addr ^ in2_src_addr);
        }
      else if (a1->dest_addr->ai_family == PF_INET6)
        {
          assert (a1->source_addr.sin6_family == PF_INET6);
          assert (a2->source_addr.sin6_family == PF_INET6);

          struct sockaddr_in6 *in1_dst;
          struct sockaddr_in6 *in1_src;
          struct sockaddr_in6 *in2_dst;
          struct sockaddr_in6 *in2_src;

          in1_dst = (struct sockaddr_in6 *) a1->dest_addr->ai_addr;
          in1_src = (struct sockaddr_in6 *) &a1->source_addr;
          in2_dst = (struct sockaddr_in6 *) a2->dest_addr->ai_addr;
          in2_src = (struct sockaddr_in6 *) &a2->source_addr;

          int i;
          for (i = 0; i < 4; ++i)
            if (in1_dst->sin6_addr.s6_addr32[i]
                != in1_src->sin6_addr.s6_addr32[i]
                || (in2_dst->sin6_addr.s6_addr32[i]
                    != in2_src->sin6_addr.s6_addr32[i]))
              break;

          if (i < 4)
            {
              bit1 = fls (ntohl (in1_dst->sin6_addr.s6_addr32[i]
                                 ^ in1_src->sin6_addr.s6_addr32[i]));
              bit2 = fls (ntohl (in2_dst->sin6_addr.s6_addr32[i]
                                 ^ in2_src->sin6_addr.s6_addr32[i]));
            }
        }

      if (bit1 > bit2)
        return -1;
      if (bit1 < bit2)
        return 1;
    }


  /* Rule 10: Otherwise, leave the order unchanged.  To ensure this
     compare with the value indicating the order in which the entries
     have been received from the services.  NB: no two entries can have
     the same order so the test will never return zero.  */
  return idx1 < idx2 ? -1 : 1;
}


static int
in6aicmp (const void *p1, const void *p2)
{
  struct in6addrinfo *a1 = (struct in6addrinfo *) p1;
  struct in6addrinfo *a2 = (struct in6addrinfo *) p2;

  return memcmp (a1->addr, a2->addr, sizeof (a1->addr));
}


/* Name of the config file for RFC 3484 sorting (for now).  */
#define GAICONF_FNAME "/etc/gai.conf"


/* Non-zero if we are supposed to reload the config file automatically
   whenever it changed.  */
static int gaiconf_reload_flag;

/* Non-zero if gaiconf_reload_flag was ever set to true.  */
static int gaiconf_reload_flag_ever_set;

/* Last modification time.  */
static struct timespec gaiconf_mtime;


libc_freeres_fn(fini)
{
  if (labels != default_labels)
    {
      const struct prefixentry *old = labels;
      labels = default_labels;
      free ((void *) old);
    }

  if (precedence != default_precedence)
    {
      const struct prefixentry *old = precedence;
      precedence = default_precedence;
      free ((void *) old);
    }

  if (scopes != default_scopes)
    {
      const struct scopeentry *old = scopes;
      scopes = default_scopes;
      free ((void *) old);
    }
}


struct prefixlist
{
  struct prefixentry entry;
  struct prefixlist *next;
};


struct scopelist
{
  struct scopeentry entry;
  struct scopelist *next;
};


static void
free_prefixlist (struct prefixlist *list)
{
  while (list != NULL)
    {
      struct prefixlist *oldp = list;
      list = list->next;
      free (oldp);
    }
}


static void
free_scopelist (struct scopelist *list)
{
  while (list != NULL)
    {
      struct scopelist *oldp = list;
      list = list->next;
      free (oldp);
    }
}


static int
prefixcmp (const void *p1, const void *p2)
{
  const struct prefixentry *e1 = (const struct prefixentry *) p1;
  const struct prefixentry *e2 = (const struct prefixentry *) p2;

  if (e1->bits < e2->bits)
    return 1;
  if (e1->bits == e2->bits)
    return 0;
  return -1;
}


static int
scopecmp (const void *p1, const void *p2)
{
  const struct scopeentry *e1 = (const struct scopeentry *) p1;
  const struct scopeentry *e2 = (const struct scopeentry *) p2;

  if (e1->netmask > e2->netmask)
    return -1;
  if (e1->netmask == e2->netmask)
    return 0;
  return 1;
}


static void
gaiconf_init (void)
{
  struct prefixlist *labellist = NULL;
  size_t nlabellist = 0;
  bool labellist_nullbits = false;
  struct prefixlist *precedencelist = NULL;
  size_t nprecedencelist = 0;
  bool precedencelist_nullbits = false;
  struct scopelist *scopelist =  NULL;
  size_t nscopelist = 0;
  bool scopelist_nullbits = false;

  FILE *fp = fopen (GAICONF_FNAME, "rc");
  if (fp != NULL)
    {
      struct stat64 st;
      if (__fxstat64 (_STAT_VER, fileno (fp), &st) != 0)
        {
          fclose (fp);
          goto no_file;
        }

      char *line = NULL;
      size_t linelen = 0;

      __fsetlocking (fp, FSETLOCKING_BYCALLER);

      while (!feof_unlocked (fp))
        {
          ssize_t n = __getline (&line, &linelen, fp);
          if (n <= 0)
            break;

          /* Handle comments.  No escaping possible so this is easy.  */
          char *cp = strchr (line, '#');
          if (cp != NULL)
            *cp = '\0';

          cp = line;
          while (isspace (*cp))
            ++cp;

          char *cmd = cp;
          while (*cp != '\0' && !isspace (*cp))
            ++cp;
          size_t cmdlen = cp - cmd;

          if (*cp != '\0')
            *cp++ = '\0';
          while (isspace (*cp))
            ++cp;

          char *val1 = cp;
          while (*cp != '\0' && !isspace (*cp))
            ++cp;
          size_t val1len = cp - cmd;

          /* We always need at least two values.  */
          if (val1len == 0)
            continue;

          if (*cp != '\0')
            *cp++ = '\0';
          while (isspace (*cp))
            ++cp;

          char *val2 = cp;
          while (*cp != '\0' && !isspace (*cp))
            ++cp;

          /*  Ignore the rest of the line.  */
          *cp = '\0';

          struct prefixlist **listp;
          size_t *lenp;
          bool *nullbitsp;
          switch (cmdlen)
            {
            case 5:
              if (strcmp (cmd, "label") == 0)
                {
                  struct in6_addr prefix;
                  unsigned long int bits;
                  unsigned long int val;
                  char *endp;

                  listp = &labellist;
                  lenp = &nlabellist;
                  nullbitsp = &labellist_nullbits;

                new_elem:
                  bits = 128;
                  __set_errno (0);
                  cp = strchr (val1, '/');
                  if (cp != NULL)
                    *cp++ = '\0';
                  if (inet_pton (AF_INET6, val1, &prefix)
                      && (cp == NULL
                          || (bits = strtoul (cp, &endp, 10)) != ULONG_MAX
                          || errno != ERANGE)
                      && *endp == '\0'
                      && bits <= 128
                      && ((val = strtoul (val2, &endp, 10)) != ULONG_MAX
                          || errno != ERANGE)
                      && *endp == '\0'
                      && val <= INT_MAX)
                    {
                      struct prefixlist *newp = malloc (sizeof (*newp));
                      if (newp == NULL)
                        {
                          free (line);
                          fclose (fp);
                          goto no_file;
                        }

                      memcpy (&newp->entry.prefix, &prefix, sizeof (prefix));
                      newp->entry.bits = bits;
                      newp->entry.val = val;
                      newp->next = *listp;
                      *listp = newp;
                      ++*lenp;
                      *nullbitsp |= bits == 0;
                    }
                }
              break;

            case 6:
              if (strcmp (cmd, "reload") == 0)
                {
                  gaiconf_reload_flag = strcmp (val1, "yes") == 0;
                  if (gaiconf_reload_flag)
                    gaiconf_reload_flag_ever_set = 1;
                }
              break;

            case 7:
              if (strcmp (cmd, "scopev4") == 0)
                {
                  struct in6_addr prefix;
                  unsigned long int bits;
                  unsigned long int val;
                  char *endp;

                  bits = 32;
                  __set_errno (0);
                  cp = strchr (val1, '/');
                  if (cp != NULL)
                    *cp++ = '\0';
                  if (inet_pton (AF_INET6, val1, &prefix))
                    {
                      bits = 128;
                      if (IN6_IS_ADDR_V4MAPPED (&prefix)
                          && (cp == NULL
                              || (bits = strtoul (cp, &endp, 10)) != ULONG_MAX
                              || errno != ERANGE)
                          && *endp == '\0'
                          && bits >= 96
                          && bits <= 128
                          && ((val = strtoul (val2, &endp, 10)) != ULONG_MAX
                              || errno != ERANGE)
                          && *endp == '\0'
                          && val <= INT_MAX)
                        {
                          struct scopelist *newp;
                        new_scope:
                          newp = malloc (sizeof (*newp));
                          if (newp == NULL)
                            {
                              free (line);
                              fclose (fp);
                              goto no_file;
                            }

                          newp->entry.netmask = htonl (bits != 96
                                                       ? (0xffffffff
                                                          << (128 - bits))
                                                       : 0);
                          newp->entry.addr32 = (prefix.s6_addr32[3]
                                                & newp->entry.netmask);
                          newp->entry.scope = val;
                          newp->next = scopelist;
                          scopelist = newp;
                          ++nscopelist;
                          scopelist_nullbits |= bits == 96;
                        }
                    }
                  else if (inet_pton (AF_INET, val1, &prefix.s6_addr32[3])
                           && (cp == NULL
                               || (bits = strtoul (cp, &endp, 10)) != ULONG_MAX
                               || errno != ERANGE)
                           && *endp == '\0'
                           && bits <= 32
                           && ((val = strtoul (val2, &endp, 10)) != ULONG_MAX
                               || errno != ERANGE)
                           && *endp == '\0'
                           && val <= INT_MAX)
                    {
                      bits += 96;
                      goto new_scope;
                    }
                }
              break;

            case 10:
              if (strcmp (cmd, "precedence") == 0)
                {
                  listp = &precedencelist;
                  lenp = &nprecedencelist;
                  nullbitsp = &precedencelist_nullbits;
                  goto new_elem;
                }
              break;
            }
        }

      free (line);

      fclose (fp);

      /* Create the array for the labels.  */
      struct prefixentry *new_labels;
      if (nlabellist > 0)
        {
          if (!labellist_nullbits)
            ++nlabellist;
          new_labels = malloc (nlabellist * sizeof (*new_labels));
          if (new_labels == NULL)
            goto no_file;

          int i = nlabellist;
          if (!labellist_nullbits)
            {
              --i;
              memset (&new_labels[i].prefix, '\0', sizeof (struct in6_addr));
              new_labels[i].bits = 0;
              new_labels[i].val = 1;
            }

          struct prefixlist *l = labellist;
          while (i-- > 0)
            {
              new_labels[i] = l->entry;
              l = l->next;
            }
          free_prefixlist (labellist);

          /* Sort the entries so that the most specific ones are at
             the beginning.  */
          qsort (new_labels, nlabellist, sizeof (*new_labels), prefixcmp);
        }
      else
        new_labels = (struct prefixentry *) default_labels;

      struct prefixentry *new_precedence;
      if (nprecedencelist > 0)
        {
          if (!precedencelist_nullbits)
            ++nprecedencelist;
          new_precedence = malloc (nprecedencelist * sizeof (*new_precedence));
          if (new_precedence == NULL)
            {
              if (new_labels != default_labels)
                free (new_labels);
              goto no_file;
            }

          int i = nprecedencelist;
          if (!precedencelist_nullbits)
            {
              --i;
              memset (&new_precedence[i].prefix, '\0',
                      sizeof (struct in6_addr));
              new_precedence[i].bits = 0;
              new_precedence[i].val = 40;
            }

          struct prefixlist *l = precedencelist;
          while (i-- > 0)
            {
              new_precedence[i] = l->entry;
              l = l->next;
            }
          free_prefixlist (precedencelist);

          /* Sort the entries so that the most specific ones are at
             the beginning.  */
          qsort (new_precedence, nprecedencelist, sizeof (*new_precedence),
                 prefixcmp);
        }
      else
        new_precedence = (struct prefixentry *) default_precedence;

      struct scopeentry *new_scopes;
      if (nscopelist > 0)
        {
          if (!scopelist_nullbits)
            ++nscopelist;
          new_scopes = malloc (nscopelist * sizeof (*new_scopes));
          if (new_scopes == NULL)
            {
              if (new_labels != default_labels)
                free (new_labels);
              if (new_precedence != default_precedence)
                free (new_precedence);
              goto no_file;
            }

          int i = nscopelist;
          if (!scopelist_nullbits)
            {
              --i;
              new_scopes[i].addr32 = 0;
              new_scopes[i].netmask = 0;
              new_scopes[i].scope = 14;
            }

          struct scopelist *l = scopelist;
          while (i-- > 0)
            {
              new_scopes[i] = l->entry;
              l = l->next;
            }
          free_scopelist (scopelist);

          /* Sort the entries so that the most specific ones are at
             the beginning.  */
          qsort (new_scopes, nscopelist, sizeof (*new_scopes),
                 scopecmp);
        }
      else
        new_scopes = (struct scopeentry *) default_scopes;

      /* Now we are ready to replace the values.  */
      const struct prefixentry *old = labels;
      labels = new_labels;
      if (old != default_labels)
        free ((void *) old);

      old = precedence;
      precedence = new_precedence;
      if (old != default_precedence)
        free ((void *) old);

      const struct scopeentry *oldscope = scopes;
      scopes = new_scopes;
      if (oldscope != default_scopes)
        free ((void *) oldscope);

      gaiconf_mtime = st.st_mtim;
    }
  else
    {
    no_file:
      free_prefixlist (labellist);
      free_prefixlist (precedencelist);
      free_scopelist (scopelist);

      /* If we previously read the file but it is gone now, free the
         old data and use the builtin one.  Leave the reload flag
         alone.  */
      fini ();
    }
}


static void
gaiconf_reload (void)
{
  struct stat64 st;
  if (__xstat64 (_STAT_VER, GAICONF_FNAME, &st) != 0
      || memcmp (&st.st_mtim, &gaiconf_mtime, sizeof (gaiconf_mtime)) != 0)
    gaiconf_init ();
}


int
getaddrinfo (const char *name, const char *service,
             const struct addrinfo *hints, struct addrinfo **pai)
{
  int i = 0, last_i = 0;
  int nresults = 0;
  struct addrinfo *p = NULL;
  struct gaih_service gaih_service, *pservice;
  struct addrinfo local_hints;

  if (name != NULL && name[0] == '*' && name[1] == 0)
    name = NULL;

  if (service != NULL && service[0] == '*' && service[1] == 0)
    service = NULL;

  if (name == NULL && service == NULL)
    return EAI_NONAME;

  if (hints == NULL)
    hints = &default_hints;

  if (hints->ai_flags
      & ~(AI_PASSIVE|AI_CANONNAME|AI_NUMERICHOST|AI_ADDRCONFIG|AI_V4MAPPED
#ifdef HAVE_LIBIDN
          |AI_IDN|AI_CANONIDN|AI_IDN_ALLOW_UNASSIGNED
          |AI_IDN_USE_STD3_ASCII_RULES
#endif
          |AI_NUMERICSERV|AI_ALL))
    return EAI_BADFLAGS;

  if ((hints->ai_flags & AI_CANONNAME) && name == NULL)
    return EAI_BADFLAGS;

  struct in6addrinfo *in6ai = NULL;
  size_t in6ailen = 0;
  bool seen_ipv4 = false;
  bool seen_ipv6 = false;
  /* We might need information about what interfaces are available.
     Also determine whether we have IPv4 or IPv6 interfaces or both.  We
     cannot cache the results since new interfaces could be added at
     any time.  */
  __check_pf (&seen_ipv4, &seen_ipv6, &in6ai, &in6ailen);

  if (hints->ai_flags & AI_ADDRCONFIG)
    {
      /* Now make a decision on what we return, if anything.  */
      if (hints->ai_family == PF_UNSPEC && (seen_ipv4 || seen_ipv6))
        {
          /* If we haven't seen both IPv4 and IPv6 interfaces we can
             narrow down the search.  */
          if ((! seen_ipv4 || ! seen_ipv6) && (seen_ipv4 || seen_ipv6))
            {
              local_hints = *hints;
              local_hints.ai_family = seen_ipv4 ? PF_INET : PF_INET6;
              hints = &local_hints;
            }
        }
      else if ((hints->ai_family == PF_INET && ! seen_ipv4)
               || (hints->ai_family == PF_INET6 && ! seen_ipv6))
        {
          /* We cannot possibly return a valid answer.  */
          free (in6ai);
          return EAI_NONAME;
        }
    }

  if (service && service[0])
    {
      char *c;
      gaih_service.name = service;
      gaih_service.num = strtoul (gaih_service.name, &c, 10);
      if (*c != '\0')
        {
          if (hints->ai_flags & AI_NUMERICSERV)
            {
              free (in6ai);
              return EAI_NONAME;
            }

          gaih_service.num = -1;
        }

      pservice = &gaih_service;
    }
  else
    pservice = NULL;

  struct addrinfo **end = &p;

  unsigned int naddrs = 0;
  if (hints->ai_family == AF_UNSPEC || hints->ai_family == AF_INET
      || hints->ai_family == AF_INET6)
    {
      last_i = gaih_inet (name, pservice, hints, end, &naddrs);
      if (last_i != 0)
        {
          freeaddrinfo (p);
          free (in6ai);

          return -(last_i & GAIH_EAI);
        }
      while (*end)
        {
          end = &((*end)->ai_next);
          ++nresults;
        }
    }
  else
    {
      free (in6ai);
      return EAI_FAMILY;
    }

  if (naddrs > 1)
    {
      /* Read the config file.  */
      __libc_once_define (static, once);
      __typeof (once) old_once = once;
      __libc_once (once, gaiconf_init);
      /* Sort results according to RFC 3484.  */
      struct sort_result results[nresults];
      size_t order[nresults];
      struct addrinfo *q;
      struct addrinfo *last = NULL;
      char *canonname = NULL;

      /* If we have information about deprecated and temporary addresses
         sort the array now.  */
      if (in6ai != NULL)
        qsort (in6ai, in6ailen, sizeof (*in6ai), in6aicmp);

      int fd = -1;
      int af = AF_UNSPEC;

      for (i = 0, q = p; q != NULL; ++i, last = q, q = q->ai_next)
        {
          results[i].dest_addr = q;
          results[i].native = -1;
          order[i] = i;

          /* If we just looked up the address for a different
             protocol, reuse the result.  */
          if (last != NULL && last->ai_addrlen == q->ai_addrlen
              && memcmp (last->ai_addr, q->ai_addr, q->ai_addrlen) == 0)
            {
              memcpy (&results[i].source_addr, &results[i - 1].source_addr,
                      results[i - 1].source_addr_len);
              results[i].source_addr_len = results[i - 1].source_addr_len;
              results[i].got_source_addr = results[i - 1].got_source_addr;
              results[i].source_addr_flags = results[i - 1].source_addr_flags;
              results[i].prefixlen = results[i - 1].prefixlen;
              results[i].index = results[i - 1].index;
            }
          else
            {
              results[i].got_source_addr = false;
              results[i].source_addr_flags = 0;
              results[i].prefixlen = 0;
              results[i].index = 0xffffffffu;

              /* We overwrite the type with SOCK_DGRAM since we do not
                 want connect() to connect to the other side.  If we
                 cannot determine the source address remember this
                 fact.  */
              if (fd == -1 || (af == AF_INET && q->ai_family == AF_INET6))
                {
                  if (fd != -1)
                  close_retry:
                    close_not_cancel_no_status (fd);
                  af = q->ai_family;
                  fd = __socket (af, SOCK_DGRAM, IPPROTO_IP);
                }
              else
                {
                  /* Reset the connection.  */
                  struct sockaddr sa = { .sa_family = AF_UNSPEC };
                  __connect (fd, &sa, sizeof (sa));
                }

              socklen_t sl = sizeof (results[i].source_addr);
              if (fd != -1
                  && __connect (fd, q->ai_addr, q->ai_addrlen) == 0
                  && __getsockname (fd,
                                    (struct sockaddr *) &results[i].source_addr,
                                    &sl) == 0)
                {
                  results[i].source_addr_len = sl;
                  results[i].got_source_addr = true;

                  if (in6ai != NULL)
                    {
                      /* See whether the source address is on the list of
                         deprecated or temporary addresses.  */
                      struct in6addrinfo tmp;

                      if (q->ai_family == AF_INET && af == AF_INET)
                        {
                          struct sockaddr_in *sinp
                            = (struct sockaddr_in *) &results[i].source_addr;
                          tmp.addr[0] = 0;
                          tmp.addr[1] = 0;
                          tmp.addr[2] = htonl (0xffff);
                          tmp.addr[3] = sinp->sin_addr.s_addr;
                        }
                      else
                        {
                          struct sockaddr_in6 *sin6p
                            = (struct sockaddr_in6 *) &results[i].source_addr;
                          memcpy (tmp.addr, &sin6p->sin6_addr, IN6ADDRSZ);
                        }

                      struct in6addrinfo *found
                        = bsearch (&tmp, in6ai, in6ailen, sizeof (*in6ai),
                                   in6aicmp);
                      if (found != NULL)
                        {
                          results[i].source_addr_flags = found->flags;
                          results[i].prefixlen = found->prefixlen;
                          results[i].index = found->index;
                        }
                    }

                  if (q->ai_family == AF_INET && af == AF_INET6)
                    {
                      /* We have to convert the address.  The socket is
                         IPv6 and the request is for IPv4.  */
                      struct sockaddr_in6 *sin6
                        = (struct sockaddr_in6 *) &results[i].source_addr;
                      struct sockaddr_in *sin
                        = (struct sockaddr_in *) &results[i].source_addr;
                      assert (IN6_IS_ADDR_V4MAPPED (sin6->sin6_addr.s6_addr32));
                      sin->sin_family = AF_INET;
                      /* We do not have to initialize sin_port since this
                         fields has the same position and size in the IPv6
                         structure.  */
                      assert (offsetof (struct sockaddr_in, sin_port)
                              == offsetof (struct sockaddr_in6, sin6_port));
                      assert (sizeof (sin->sin_port)
                              == sizeof (sin6->sin6_port));
                      memcpy (&sin->sin_addr,
                              &sin6->sin6_addr.s6_addr32[3], INADDRSZ);
                      results[i].source_addr_len = sizeof (struct sockaddr_in);
                    }
                }
              else if (errno == EAFNOSUPPORT && af == AF_INET6
                       && q->ai_family == AF_INET)
                /* This could mean IPv6 sockets are IPv6-only.  */
                goto close_retry;
              else
                /* Just make sure that if we have to process the same
                   address again we do not copy any memory.  */
                results[i].source_addr_len = 0;
            }

          /* Remember the canonical name.  */
          if (q->ai_canonname != NULL)
            {
              assert (canonname == NULL);
              canonname = q->ai_canonname;
              q->ai_canonname = NULL;
            }
        }

      if (fd != -1)
        close_not_cancel_no_status (fd);

      /* We got all the source addresses we can get, now sort using
         the information.  */
      struct sort_result_combo src
        = { .results = results, .nresults = nresults };
      if (__builtin_expect (gaiconf_reload_flag_ever_set, 0))
        {
          __libc_lock_define_initialized (static, lock);

          __libc_lock_lock (lock);
          if (old_once && gaiconf_reload_flag)
            gaiconf_reload ();
          qsort_r (order, nresults, sizeof (order[0]), rfc3484_sort, &src);
          __libc_lock_unlock (lock);
        }
      else
        qsort_r (order, nresults, sizeof (order[0]), rfc3484_sort, &src);

      /* Queue the results up as they come out of sorting.  */
      q = p = results[order[0]].dest_addr;
      for (i = 1; i < nresults; ++i)
        q = q->ai_next = results[order[i]].dest_addr;
      q->ai_next = NULL;

      /* Fill in the canonical name into the new first entry.  */
      p->ai_canonname = canonname;
    }

  free (in6ai);

  if (p)
    {
      *pai = p;
      return 0;
    }

  return last_i ? -(last_i & GAIH_EAI) : EAI_NONAME;
}
libc_hidden_def (getaddrinfo)

static_link_warning (getaddrinfo)

void
freeaddrinfo (struct addrinfo *ai)
{
  struct addrinfo *p;

  while (ai != NULL)
    {
      p = ai;
      ai = ai->ai_next;
      free (p->ai_canonname);
      free (p);
    }
}
libc_hidden_def (freeaddrinfo)