StdLib/BsdSocketLib/res_send.c - device/linaro/bootloader/edk2 - Git at Google

 /*
  * Copyright (c) 1985, 1989, 1993
  *    The Regents of the University of California.  All rights reserved.
  *
  * Portions copyright (c) 1999, 2000
  * Intel Corporation.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. 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.
  *
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
  *
  *    This product includes software developed by the University of
  *    California, Berkeley, Intel Corporation, and its contributors.
  *
  * 4. Neither the name of University, Intel Corporation, or their respective
  *    contributors may be used to endorse or promote products derived from
  *    this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE REGENTS, INTEL CORPORATION AND
  * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS,
  * INTEL CORPORATION 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.
  *
  */

 /*
  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies, and that
  * the name of Digital Equipment Corporation not be used in advertising or
  * publicity pertaining to distribution of the document or software without
  * specific, written prior permission.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  * SOFTWARE.
  */

 /*
  * Portions Copyright (c) 1996 by Internet Software Consortium.
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  * SOFTWARE.
  */

 #if defined(LIBC_SCCS) && !defined(lint)
 static char sccsid[] = "@(#)res_send.c  8.1 (Berkeley) 6/4/93";
 static char orig_rcsid[] = "From: Id: res_send.c,v 8.20 1998/04/06 23:27:51 halley Exp $";
 static char rcsid[] = "$Id: res_send.c,v 1.1.1.1 2003/11/19 01:51:39 kyu3 Exp $";
 #endif /* LIBC_SCCS and not lint */

 /*
  * Send query to name server and wait for reply.
  */

 #include <sys/types.h>
 #include <sys/param.h>
 #include <sys/select.h>
 #include <sys/socket.h>
 #include <sys/time.h>
 #include <sys/uio.h>

 #include <netinet/in.h>
 #include <arpa/nameser.h>
 #include <arpa/inet.h>

 #include <errno.h>
 #include <netdb.h>
 #include <resolv.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 #include "res_config.h"

 #ifndef _ORG_FREEBSD_
 #define NOPOLL
 #endif

 #ifdef NOPOLL           /* libc_r doesn't wrap poll yet() */
 #else
 #include <poll.h>
 static int use_poll = 1;    /* adapt to poll() syscall availability */
                 /* 0 = not present, 1 = try it, 2 = exists */
 #endif

 static int s = -1;      /* socket used for communications */
 static int connected = 0;   /* is the socket connected */
 static int vc = 0;      /* is the socket a virtual circuit? */
 static res_send_qhook Qhook = NULL;
 static res_send_rhook Rhook = NULL;


 #define CAN_RECONNECT 1

 #ifndef DEBUG
 #   define Dprint(cond, args) /*empty*/
 #   define DprintQ(cond, args, query, size) /*empty*/
 #   define Aerror(file, string, error, address) /*empty*/
 #   define Perror(file, string, error) /*empty*/
 #else
 #   define Dprint(cond, args) if (cond) {fprintf args;} else {}
 #   define DprintQ(cond, args, query, size) if (cond) {\
             fprintf args;\
             __fp_nquery(query, size, stdout);\
         } else {}

 static void
 Aerror(
     FILE *file,
     char *string,
     int error,
     struct sockaddr_in address
     )
 {
     int save = errno;

     if (_res.options & RES_DEBUG) {
         fprintf(file, "res_send: %s ([%s].%u): %s\n",
             string,
             inet_ntoa(address.sin_addr),
             ntohs(address.sin_port),
             strerror(error));
     }
     errno = save;
 }


 static void
 Perror(
     FILE *file,
     char *string,
     int error
     )
 {
     int save = errno;

     if (_res.options & RES_DEBUG) {
         fprintf(file, "res_send: %s: %s\n",
             string, strerror(error));
     }
     errno = save;
 }
 #endif

 void
 res_send_setqhook(
     res_send_qhook hook
     )
 {

     Qhook = hook;
 }

 void
 res_send_setrhook(
     res_send_rhook hook
     )
 {

     Rhook = hook;
 }

 /* int
  * res_isourserver(ina)
  *  looks up "ina" in _res.ns_addr_list[]
  * returns:
  *  0  : not found
  *  >0 : found
  * author:
  *  paul vixie, 29may94
  */
 int
 res_isourserver(
     const struct sockaddr_in *inp
     )
 {
     struct sockaddr_in ina;
     int ns, ret;

     ina = *inp;
     ret = 0;
     for (ns = 0;  ns < _res.nscount;  ns++) {
         const struct sockaddr_in *srv = &_res.nsaddr_list[ns];

         if (srv->sin_family == ina.sin_family &&
             srv->sin_port == ina.sin_port &&
             (srv->sin_addr.s_addr == INADDR_ANY ||
              srv->sin_addr.s_addr == ina.sin_addr.s_addr)) {
             ret++;
             break;
         }
     }
     return (ret);
 }

 /* int
  * res_nameinquery(name, type, class, buf, eom)
  *  look for (name,type,class) in the query section of packet (buf,eom)
  * requires:
  *  buf + HFIXEDSZ <= eom
  * returns:
  *  -1 : format error
  *  0  : not found
  *  >0 : found
  * author:
  *  paul vixie, 29may94
  */
 int
 res_nameinquery(
     const char *name,
     int type,
     int class,
     const u_char *buf,
     const u_char *eom
     )
 {
     const u_char *cp = buf + HFIXEDSZ;
     int qdcount = ntohs(((HEADER*)buf)->qdcount);

     while (qdcount-- > 0) {
         char tname[MAXDNAME+1];
         int n, ttype, tclass;

         n = dn_expand(buf, eom, cp, tname, sizeof tname);
         if (n < 0)
             return (-1);
         cp += n;
         if (cp + 2 * INT16SZ > eom)
             return (-1);
         ttype = ns_get16(cp); cp += INT16SZ;
         tclass = ns_get16(cp); cp += INT16SZ;
         if (ttype == type &&
             tclass == class &&
             strcasecmp(tname, name) == 0)
             return (1);
     }
     return (0);
 }

 /* int
  * res_queriesmatch(buf1, eom1, buf2, eom2)
  *  is there a 1:1 mapping of (name,type,class)
  *  in (buf1,eom1) and (buf2,eom2)?
  * returns:
  *  -1 : format error
  *  0  : not a 1:1 mapping
  *  >0 : is a 1:1 mapping
  * author:
  *  paul vixie, 29may94
  */
 int
 res_queriesmatch(
     const u_char *buf1,
     const u_char *eom1,
     const u_char *buf2,
     const u_char *eom2
     )
 {
     const u_char *cp = buf1 + HFIXEDSZ;
     int qdcount = ntohs(((HEADER*)buf1)->qdcount);

     if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
         return (-1);

     /*
      * Only header section present in replies to
      * dynamic update packets.
      */
     if ( (((HEADER *)buf1)->opcode == ns_o_update) &&
          (((HEADER *)buf2)->opcode == ns_o_update) )
         return (1);

     if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
         return (0);
     while (qdcount-- > 0) {
         char tname[MAXDNAME+1];
         int n, ttype, tclass;

         n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
         if (n < 0)
             return (-1);
         cp += n;
         if (cp + 2 * INT16SZ > eom1)
             return (-1);
         ttype = ns_get16(cp);   cp += INT16SZ;
         tclass = ns_get16(cp); cp += INT16SZ;
         if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
             return (0);
     }
     return (1);
 }

 int
 res_send(
     const u_char *buf,
     int buflen,
     u_char *ans,
     int anssiz
     )
 {
     HEADER *hp = (HEADER *) buf;
     HEADER *anhp = (HEADER *) ans;
     int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns;
     ssize_t n;
     u_int32_t badns;    /* XXX NSMAX can't exceed #/bits in this variable */

     if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
         /* errno should have been set by res_init() in this case. */
         return (-1);
     }
     if (anssiz < HFIXEDSZ) {
         errno = EINVAL;
         return (-1);
     }
     DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY),
         (stdout, ";; res_send()\n"), buf, buflen);
     v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
     gotsomewhere = 0;
     connreset = 0;
     terrno = ETIMEDOUT;
     badns = 0;

     /*
      * Send request, RETRY times, or until successful
      */
     for (try = 0; try < _res.retry; try++) {
         for (ns = 0; ns < _res.nscount; ns++) {
         struct sockaddr_in *nsap = &_res.nsaddr_list[ns];
     same_ns:
         if (badns & (1 << ns)) {
             res_close();
             goto next_ns;
         }

         if (Qhook) {
             int done = 0, loops = 0;

             do {
                 res_sendhookact act;

                 act = (*Qhook)(&nsap, &buf, &buflen,
                            ans, anssiz, &resplen);
                 switch (act) {
                 case res_goahead:
                     done = 1;
                     break;
                 case res_nextns:
                     res_close();
                     goto next_ns;
                 case res_done:
                     return (resplen);
                 case res_modified:
                     /* give the hook another try */
                     if (++loops < 42) /*doug adams*/
                         break;
                     /*FALLTHROUGH*/
                 case res_error:
                     /*FALLTHROUGH*/
                 default:
                     return (-1);
                 }
             } while (!done);
         }

         Dprint(_res.options & RES_DEBUG,
                (stdout, ";; Querying server (# %d) address = %s\n",
             ns + 1, inet_ntoa(nsap->sin_addr)));

         if (v_circuit) {
             int truncated;
             struct iovec iov[2];
             u_short len;
             u_char *cp;

             /*
              * Use virtual circuit;
              * at most one attempt per server.
              */
             try = _res.retry;
             truncated = 0;
             if (s < 0 || !vc || hp->opcode == ns_o_update) {
                 if (s >= 0)
                     res_close();

                 s = socket(PF_INET, SOCK_STREAM, 0);
                 if (s < 0) {
                     terrno = errno;
                     Perror(stderr, "socket(vc)", errno);
                     return (-1);
                 }
                 errno = 0;
                 nsap->sin_len = sizeof ( *nsap );
                 if (connect(s, (struct sockaddr *)nsap,
                         sizeof *nsap) < 0) {
                     terrno = errno;
                     Aerror(stderr, "connect/vc",
                            errno, *nsap);
                     badns |= (1 << ns);
                     res_close();
                     goto next_ns;
                 }
                 vc = 1;
             }
             /*
              * Send length & message
              */
             putshort((u_short)buflen, (u_char*)&len);
             iov[0].iov_base = (caddr_t)&len;
             iov[0].iov_len = INT16SZ;
             iov[1].iov_base = (caddr_t)buf;
             iov[1].iov_len = buflen;
             if (writev(s, iov, 2) != (INT16SZ + buflen)) {
                 terrno = errno;
                 Perror(stderr, "write failed", errno);
                 badns |= (1 << ns);
                 res_close();
                 goto next_ns;
             }
             /*
              * Receive length & response
              */
 read_len:
             cp = ans;
             len = INT16SZ;
             while ((n = read(s, (char *)cp, (int)len)) > 0) {
                 cp += n;
                 len = (u_short)( len - n );
                 if (len <= 0)
                     break;
             }
             if (n <= 0) {
                 terrno = errno;
                 Perror(stderr, "read failed", errno);
                 res_close();
                 /*
                  * A long running process might get its TCP
                  * connection reset if the remote server was
                  * restarted.  Requery the server instead of
                  * trying a new one.  When there is only one
                  * server, this means that a query might work
                  * instead of failing.  We only allow one reset
                  * per query to prevent looping.
                  */
                 if (terrno == ECONNRESET && !connreset) {
                     connreset = 1;
                     res_close();
                     goto same_ns;
                 }
                 res_close();
                 goto next_ns;
             }
             resplen = ns_get16(ans);
             if (resplen > anssiz) {
                 Dprint(_res.options & RES_DEBUG,
                        (stdout, ";; response truncated\n")
                        );
                 truncated = 1;
                 len = (ushort)anssiz;
             } else
                 len = (ushort)resplen;
             if (len < HFIXEDSZ) {
                 /*
                  * Undersized message.
                  */
                 Dprint(_res.options & RES_DEBUG,
                        (stdout, ";; undersized: %d\n", len));
                 terrno = EMSGSIZE;
                 badns |= (1 << ns);
                 res_close();
                 goto next_ns;
             }
             cp = ans;
             while (len != 0 &&
                    (n = read(s, (char *)cp, (int)len)) > 0) {
                 cp += n;
                 len = (u_short)( len - n );
             }
             if (n <= 0) {
                 terrno = errno;
                 Perror(stderr, "read(vc)", errno);
                 res_close();
                 goto next_ns;
             }
             if (truncated) {
                 /*
                  * Flush rest of answer
                  * so connection stays in synch.
                  */
                 anhp->tc = 1;
                 len = (ushort)( resplen - anssiz );
                 while (len != 0) {
                     char junk[PACKETSZ];

                     n = (len > sizeof(junk)
                          ? sizeof(junk)
                          : len);
                     if ((n = read(s, junk, n)) > 0)
                         len = (u_short)( len - n );
                     else
                         break;
                 }
             }
             /*
              * The calling applicating has bailed out of
              * a previous call and failed to arrange to have
              * the circuit closed or the server has got
              * itself confused. Anyway drop the packet and
              * wait for the correct one.
              */
             if (hp->id != anhp->id) {
                 DprintQ((_res.options & RES_DEBUG) ||
                     (_res.pfcode & RES_PRF_REPLY),
                     (stdout, ";; old answer (unexpected):\n"),
                     ans, (resplen>anssiz)?anssiz:resplen);
                 goto read_len;
             }
         } else {
             /*
              * Use datagrams.
              */
 #ifndef NOPOLL
             struct pollfd pfd;
             int msec;
 #endif
             struct timeval timeout;
             fd_set dsmask, *dsmaskp;
             int dsmasklen;
             struct sockaddr_in from;
             int fromlen;

             if ((s < 0) || vc) {
                 if (vc)
                     res_close();
                 s = socket(PF_INET, SOCK_DGRAM, 0);
                 if (s < 0) {
 #ifndef CAN_RECONNECT
  bad_dg_sock:
 #endif
                     terrno = errno;
                     Perror(stderr, "socket(dg)", errno);
                     return (-1);
                 }
                 connected = 0;
             }
 #ifndef CANNOT_CONNECT_DGRAM
             /*
              * On a 4.3BSD+ machine (client and server,
              * actually), sending to a nameserver datagram
              * port with no nameserver will cause an
              * ICMP port unreachable message to be returned.
              * If our datagram socket is "connected" to the
              * server, we get an ECONNREFUSED error on the next
              * socket operation, and select returns if the
              * error message is received.  We can thus detect
              * the absence of a nameserver without timing out.
              * If we have sent queries to at least two servers,
              * however, we don't want to remain connected,
              * as we wish to receive answers from the first
              * server to respond.
              */
             if (_res.nscount == 1 || (try == 0 && ns == 0)) {
                 /*
                  * Connect only if we are sure we won't
                  * receive a response from another server.
                  */
                 if (!connected) {
                     nsap->sin_len = sizeof ( *nsap );
                     if (connect(s, (struct sockaddr *)nsap,
                             sizeof *nsap
                             ) < 0) {
                         Aerror(stderr,
                                "connect(dg)",
                                errno, *nsap);
                         badns |= (1 << ns);
                         res_close();
                         goto next_ns;
                     }
                     connected = 1;
                 }
                 if (send(s, (char*)buf, buflen, 0) != buflen) {
                     Perror(stderr, "send", errno);
                     badns |= (1 << ns);
                     res_close();
                     goto next_ns;
                 }
             } else {
                 /*
                  * Disconnect if we want to listen
                  * for responses from more than one server.
                  */
                 if (connected) {
 #ifdef CAN_RECONNECT
                     struct sockaddr_in no_addr;

                     no_addr.sin_family = AF_INET;
                     no_addr.sin_addr.s_addr = INADDR_ANY;
                     no_addr.sin_port = 0;
                     (void) connect(s,
                                (struct sockaddr *)
                                 &no_addr,
                                sizeof no_addr);
 #else
                     int s1 = socket(PF_INET, SOCK_DGRAM,0);
                     if (s1 < 0)
                         goto bad_dg_sock;
                     (void) dup2(s1, s);
                     (void) close(s1);
                     Dprint(_res.options & RES_DEBUG,
                         (stdout, ";; new DG socket\n"))
 #endif /* CAN_RECONNECT */
                     connected = 0;
                     errno = 0;
                 }
 #endif /* !CANNOT_CONNECT_DGRAM */
                 if (sendto(s, (char*)buf, buflen, 0,
                        (struct sockaddr *)nsap,
                        sizeof *nsap)
                     != buflen) {
                     Aerror(stderr, "sendto", errno, *nsap);
                     badns |= (1 << ns);
                     res_close();
                     goto next_ns;
                 }
 #ifndef CANNOT_CONNECT_DGRAM
             }
 #endif /* !CANNOT_CONNECT_DGRAM */

             /*
              * Wait for reply
              */
 #ifndef NOPOLL
     othersyscall:
             if (use_poll) {
                 msec = (_res.retrans << try) * 1000;
                 if (try > 0)
                     msec /= _res.nscount;
                 if (msec <= 0)
                     msec = 1000;
             } else {
 #endif
                 timeout.tv_sec = (_res.retrans << try);
                 if (try > 0)
                     timeout.tv_sec /= _res.nscount;
                 if ((long) timeout.tv_sec <= 0)
                     timeout.tv_sec = 1;
                 timeout.tv_usec = 0;
 #ifndef NOPOLL
             }
 #endif
     wait:
             if (s < 0) {
                 Perror(stderr, "s out-of-bounds", EMFILE);
                 res_close();
                 goto next_ns;
             }
 #ifndef NOPOLL
             if (use_poll) {
                 struct sigaction sa, osa;
                 int sigsys_installed = 0;

                 pfd.fd = s;
                 pfd.events = POLLIN;
                 if (use_poll == 1) {
                     bzero(&sa, sizeof(sa));
                     sa.sa_handler = SIG_IGN;
                     if (sigaction(SIGSYS, &sa, &osa) >= 0)
                         sigsys_installed = 1;
                 }
                 n = poll(&pfd, 1, msec);
                 if (sigsys_installed == 1) {
                     int oerrno = errno;
                     sigaction(SIGSYS, &osa, NULL);
                     errno = oerrno;
                 }
                 /* XXX why does nosys() return EINVAL? */
                 if (n < 0 && (errno == ENOSYS ||
                     errno == EINVAL)) {
                     use_poll = 0;
                     goto othersyscall;
                 } else if (use_poll == 1)
                     use_poll = 2;
                 if (n < 0) {
                     if (errno == EINTR)
                         goto wait;
                     Perror(stderr, "poll", errno);
                     res_close();
                     goto next_ns;
                 }
             } else {
 #endif
                 dsmasklen = howmany(s + 1, NFDBITS) *
                         sizeof(fd_mask);
                 if (dsmasklen > sizeof(fd_set)) {
                     dsmaskp = (fd_set *)malloc(dsmasklen);
                     if (dsmaskp == NULL) {
                         res_close();
                         goto next_ns;
                     }
                 } else
                     dsmaskp = &dsmask;
                 /* only zero what we need */
                 memset((char *)dsmaskp, 0, dsmasklen);
                 FD_SET(s, dsmaskp);
                 n = select(s + 1, dsmaskp, (fd_set *)NULL,
                        (fd_set *)NULL, &timeout);
                 if (dsmaskp != &dsmask)
                     free(dsmaskp);
                 if (n < 0) {
                     if (errno == EINTR)
                         goto wait;
                     Perror(stderr, "select", errno);
                     res_close();
                     goto next_ns;
                 }
 #ifndef NOPOLL
             }
 #endif

             if (n == 0) {
                 /*
                  * timeout
                  */
                 Dprint(_res.options & RES_DEBUG,
                        (stdout, ";; timeout\n"));
                 gotsomewhere = 1;
                 res_close();
                 goto next_ns;
             }
             errno = 0;
             fromlen = sizeof(struct sockaddr_in);
             resplen = (int)recvfrom(s, (char*)ans, anssiz, 0,
                        (struct sockaddr *)&from, (socklen_t *)&fromlen);
             if (resplen <= 0) {
                 Perror(stderr, "recvfrom", errno);
                 res_close();
                 goto next_ns;
             }
             gotsomewhere = 1;
             if (resplen < HFIXEDSZ) {
                 /*
                  * Undersized message.
                  */
                 Dprint(_res.options & RES_DEBUG,
                        (stdout, ";; undersized: %d\n",
                     resplen));
                 terrno = EMSGSIZE;
                 badns |= (1 << ns);
                 res_close();
                 goto next_ns;
             }
             if (hp->id != anhp->id) {
                 /*
                  * response from old query, ignore it.
                  * XXX - potential security hazard could
                  *   be detected here.
                  */
                 DprintQ((_res.options & RES_DEBUG) ||
                     (_res.pfcode & RES_PRF_REPLY),
                     (stdout, ";; old answer:\n"),
                     ans, (resplen>anssiz)?anssiz:resplen);
                 goto wait;
             }
 #ifdef CHECK_SRVR_ADDR
             if (!(_res.options & RES_INSECURE1) &&
                 !res_isourserver(&from)) {
                 /*
                  * response from wrong server? ignore it.
                  * XXX - potential security hazard could
                  *   be detected here.
                  */
                 DprintQ((_res.options & RES_DEBUG) ||
                     (_res.pfcode & RES_PRF_REPLY),
                     (stdout, ";; not our server:\n"),
                     ans, (resplen>anssiz)?anssiz:resplen);
                 goto wait;
             }
 #endif
             if (!(_res.options & RES_INSECURE2) &&
                 !res_queriesmatch(buf, buf + buflen,
                           ans, ans + anssiz)) {
                 /*
                  * response contains wrong query? ignore it.
                  * XXX - potential security hazard could
                  *   be detected here.
                  */
                 DprintQ((_res.options & RES_DEBUG) ||
                     (_res.pfcode & RES_PRF_REPLY),
                     (stdout, ";; wrong query name:\n"),
                     ans, (resplen>anssiz)?anssiz:resplen);
                 goto wait;
             }
             if (anhp->rcode == SERVFAIL ||
                 anhp->rcode == NOTIMP ||
                 anhp->rcode == REFUSED) {
                 DprintQ(_res.options & RES_DEBUG,
                     (stdout, "server rejected query:\n"),
                     ans, (resplen>anssiz)?anssiz:resplen);
                 badns |= (1 << ns);
                 res_close();
                 /* don't retry if called from dig */
                 if (!_res.pfcode)
                     goto next_ns;
             }
             if (!(_res.options & RES_IGNTC) && anhp->tc) {
                 /*
                  * get rest of answer;
                  * use TCP with same server.
                  */
                 Dprint(_res.options & RES_DEBUG,
                        (stdout, ";; truncated answer\n"));
                 v_circuit = 1;
                 res_close();
                 goto same_ns;
             }
         } /*if vc/dg*/
         Dprint((_res.options & RES_DEBUG) ||
                ((_res.pfcode & RES_PRF_REPLY) &&
             (_res.pfcode & RES_PRF_HEAD1)),
                (stdout, ";; got answer:\n"));
         if((_res.options & RES_DEBUG) ||
             (_res.pfcode & RES_PRF_REPLY)) {
             __fp_nquery(ans, (resplen>anssiz)?anssiz:resplen, stdout);
         }
         /*
          * If using virtual circuits, we assume that the first server
          * is preferred over the rest (i.e. it is on the local
          * machine) and only keep that one open.
          * If we have temporarily opened a virtual circuit,
          * or if we haven't been asked to keep a socket open,
          * close the socket.
          */
         if ((v_circuit && (!(_res.options & RES_USEVC) || ns != 0)) ||
             !(_res.options & RES_STAYOPEN)) {
             res_close();
         }
         if (Rhook) {
             int done = 0, loops = 0;

             do {
                 res_sendhookact act;

                 act = (*Rhook)(nsap, buf, buflen,
                            ans, anssiz, &resplen);
                 switch (act) {
                 case res_goahead:
                 case res_done:
                     done = 1;
                     break;
                 case res_nextns:
                     res_close();
                     goto next_ns;
                 case res_modified:
                     /* give the hook another try */
                     if (++loops < 42) /*doug adams*/
                         break;
                     /*FALLTHROUGH*/
                 case res_error:
                     /*FALLTHROUGH*/
                 default:
                     return (-1);
                 }
             } while (!done);

         }
         return (resplen);
     next_ns: ;
        } /*foreach ns*/
     } /*foreach retry*/
     res_close();
     if (!v_circuit) {
         if (!gotsomewhere)
             errno = ECONNREFUSED;   /* no nameservers found */
         else
             errno = ETIMEDOUT;  /* no answer obtained */
     } else
         errno = terrno;
     return (-1);
 }

 /*
  * This routine is for closing the socket if a virtual circuit is used and
  * the program wants to close it.  This provides support for endhostent()
  * which expects to close the socket.
  *
  * This routine is not expected to be user visible.
  */
 void
 res_close()
 {
     if (s >= 0) {
         (void) close(s);
         s = -1;
         connected = 0;
         vc = 0;
     }
 }
	/*
	* Copyright (c) 1985, 1989, 1993
	* The Regents of the University of California. All rights reserved.
	*
	* Portions copyright (c) 1999, 2000
	* Intel Corporation.
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. 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.
	*
	* 3. All advertising materials mentioning features or use of this software
	* must display the following acknowledgement:
	*
	* This product includes software developed by the University of
	* California, Berkeley, Intel Corporation, and its contributors.
	*
	* 4. Neither the name of University, Intel Corporation, or their respective
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE REGENTS, INTEL CORPORATION AND
	* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
	* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
	* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS,
	* INTEL CORPORATION 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.
	*
	*/

	/*
	* Portions Copyright (c) 1993 by Digital Equipment Corporation.
	*
	* Permission to use, copy, modify, and distribute this software for any
	* purpose with or without fee is hereby granted, provided that the above
	* copyright notice and this permission notice appear in all copies, and that
	* the name of Digital Equipment Corporation not be used in advertising or
	* publicity pertaining to distribution of the document or software without
	* specific, written prior permission.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
	* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
	* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
	* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
	* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
	* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
	* SOFTWARE.
	*/

	/*
	* Portions Copyright (c) 1996 by Internet Software Consortium.
	*
	* Permission to use, copy, modify, and distribute this software for any
	* purpose with or without fee is hereby granted, provided that the above
	* copyright notice and this permission notice appear in all copies.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
	* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
	* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
	* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
	* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
	* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
	* SOFTWARE.
	*/

	#if defined(LIBC_SCCS) && !defined(lint)
	static char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
	static char orig_rcsid[] = "From: Id: res_send.c,v 8.20 1998/04/06 23:27:51 halley Exp $";
	static char rcsid[] = "$Id: res_send.c,v 1.1.1.1 2003/11/19 01:51:39 kyu3 Exp $";
	#endif /* LIBC_SCCS and not lint */

	/*
	* Send query to name server and wait for reply.
	*/

	#include <sys/types.h>
	#include <sys/param.h>
	#include <sys/select.h>
	#include <sys/socket.h>
	#include <sys/time.h>
	#include <sys/uio.h>

	#include <netinet/in.h>
	#include <arpa/nameser.h>
	#include <arpa/inet.h>

	#include <errno.h>
	#include <netdb.h>
	#include <resolv.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>

	#include "res_config.h"

	#ifndef _ORG_FREEBSD_
	#define NOPOLL
	#endif

	#ifdef NOPOLL /* libc_r doesn't wrap poll yet() */
	#else
	#include <poll.h>
	static int use_poll = 1; /* adapt to poll() syscall availability */
	/* 0 = not present, 1 = try it, 2 = exists */
	#endif

	static int s = -1; /* socket used for communications */
	static int connected = 0; /* is the socket connected */
	static int vc = 0; /* is the socket a virtual circuit? */
	static res_send_qhook Qhook = NULL;
	static res_send_rhook Rhook = NULL;


	#define CAN_RECONNECT 1

	#ifndef DEBUG
	# define Dprint(cond, args) /empty/
	# define DprintQ(cond, args, query, size) /empty/
	# define Aerror(file, string, error, address) /empty/
	# define Perror(file, string, error) /empty/
	#else
	# define Dprint(cond, args) if (cond) {fprintf args;} else {}
	# define DprintQ(cond, args, query, size) if (cond) {\
	fprintf args;\
	__fp_nquery(query, size, stdout);\
	} else {}

	static void
	Aerror(
	FILE *file,
	char *string,
	int error,
	struct sockaddr_in address
	)
	{
	int save = errno;

	if (_res.options & RES_DEBUG) {
	fprintf(file, "res_send: %s ([%s].%u): %s\n",
	string,
	inet_ntoa(address.sin_addr),
	ntohs(address.sin_port),
	strerror(error));
	}
	errno = save;
	}


	static void
	Perror(
	FILE *file,
	char *string,
	int error
	)
	{
	int save = errno;

	if (_res.options & RES_DEBUG) {
	fprintf(file, "res_send: %s: %s\n",
	string, strerror(error));
	}
	errno = save;
	}
	#endif

	void
	res_send_setqhook(
	res_send_qhook hook
	)
	{

	Qhook = hook;
	}

	void
	res_send_setrhook(
	res_send_rhook hook
	)
	{

	Rhook = hook;
	}

	/* int
	* res_isourserver(ina)
	* looks up "ina" in _res.ns_addr_list[]
	* returns:
	* 0 : not found
	* >0 : found
	* author:
	* paul vixie, 29may94
	*/
	int
	res_isourserver(
	const struct sockaddr_in *inp
	)
	{
	struct sockaddr_in ina;
	int ns, ret;

	ina = *inp;
	ret = 0;
	for (ns = 0; ns < _res.nscount; ns++) {
	const struct sockaddr_in *srv = &_res.nsaddr_list[ns];

	if (srv->sin_family == ina.sin_family &&
	srv->sin_port == ina.sin_port &&
	(srv->sin_addr.s_addr == INADDR_ANY \|\|
	srv->sin_addr.s_addr == ina.sin_addr.s_addr)) {
	ret++;
	break;
	}
	}
	return (ret);
	}

	/* int
	* res_nameinquery(name, type, class, buf, eom)
	* look for (name,type,class) in the query section of packet (buf,eom)
	* requires:
	* buf + HFIXEDSZ <= eom
	* returns:
	* -1 : format error
	* 0 : not found
	* >0 : found
	* author:
	* paul vixie, 29may94
	*/
	int
	res_nameinquery(
	const char *name,
	int type,
	int class,
	const u_char *buf,
	const u_char *eom
	)
	{
	const u_char *cp = buf + HFIXEDSZ;
	int qdcount = ntohs(((HEADER*)buf)->qdcount);

	while (qdcount-- > 0) {
	char tname[MAXDNAME+1];
	int n, ttype, tclass;

	n = dn_expand(buf, eom, cp, tname, sizeof tname);
	if (n < 0)
	return (-1);
	cp += n;
	if (cp + 2 * INT16SZ > eom)
	return (-1);
	ttype = ns_get16(cp); cp += INT16SZ;
	tclass = ns_get16(cp); cp += INT16SZ;
	if (ttype == type &&
	tclass == class &&
	strcasecmp(tname, name) == 0)
	return (1);
	}
	return (0);
	}

	/* int
	* res_queriesmatch(buf1, eom1, buf2, eom2)
	* is there a 1:1 mapping of (name,type,class)
	* in (buf1,eom1) and (buf2,eom2)?
	* returns:
	* -1 : format error
	* 0 : not a 1:1 mapping
	* >0 : is a 1:1 mapping
	* author:
	* paul vixie, 29may94
	*/
	int
	res_queriesmatch(
	const u_char *buf1,
	const u_char *eom1,
	const u_char *buf2,
	const u_char *eom2
	)
	{
	const u_char *cp = buf1 + HFIXEDSZ;
	int qdcount = ntohs(((HEADER*)buf1)->qdcount);

	if (buf1 + HFIXEDSZ > eom1 \|\| buf2 + HFIXEDSZ > eom2)
	return (-1);

	/*
	* Only header section present in replies to
	* dynamic update packets.
	*/
	if ( (((HEADER *)buf1)->opcode == ns_o_update) &&
	(((HEADER *)buf2)->opcode == ns_o_update) )
	return (1);

	if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
	return (0);
	while (qdcount-- > 0) {
	char tname[MAXDNAME+1];
	int n, ttype, tclass;

	n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
	if (n < 0)
	return (-1);
	cp += n;
	if (cp + 2 * INT16SZ > eom1)
	return (-1);
	ttype = ns_get16(cp); cp += INT16SZ;
	tclass = ns_get16(cp); cp += INT16SZ;
	if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
	return (0);
	}
	return (1);
	}

	int
	res_send(
	const u_char *buf,
	int buflen,
	u_char *ans,
	int anssiz
	)
	{
	HEADER hp = (HEADER ) buf;
	HEADER anhp = (HEADER ) ans;
	int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns;
	ssize_t n;
	u_int32_t badns; /* XXX NSMAX can't exceed #/bits in this variable */

	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
	/* errno should have been set by res_init() in this case. */
	return (-1);
	}
	if (anssiz < HFIXEDSZ) {
	errno = EINVAL;
	return (-1);
	}
	DprintQ((_res.options & RES_DEBUG) \|\| (_res.pfcode & RES_PRF_QUERY),
	(stdout, ";; res_send()\n"), buf, buflen);
	v_circuit = (_res.options & RES_USEVC) \|\| buflen > PACKETSZ;
	gotsomewhere = 0;
	connreset = 0;
	terrno = ETIMEDOUT;
	badns = 0;

	/*
	* Send request, RETRY times, or until successful
	*/
	for (try = 0; try < _res.retry; try++) {
	for (ns = 0; ns < _res.nscount; ns++) {
	struct sockaddr_in *nsap = &_res.nsaddr_list[ns];
	same_ns:
	if (badns & (1 << ns)) {
	res_close();
	goto next_ns;
	}

	if (Qhook) {
	int done = 0, loops = 0;

	do {
	res_sendhookact act;

	act = (*Qhook)(&nsap, &buf, &buflen,
	ans, anssiz, &resplen);
	switch (act) {
	case res_goahead:
	done = 1;
	break;
	case res_nextns:
	res_close();
	goto next_ns;
	case res_done:
	return (resplen);
	case res_modified:
	/* give the hook another try */
	if (++loops < 42) /doug adams/
	break;
	/FALLTHROUGH/
	case res_error:
	/FALLTHROUGH/
	default:
	return (-1);
	}
	} while (!done);
	}

	Dprint(_res.options & RES_DEBUG,
	(stdout, ";; Querying server (# %d) address = %s\n",
	ns + 1, inet_ntoa(nsap->sin_addr)));

	if (v_circuit) {
	int truncated;
	struct iovec iov[2];
	u_short len;
	u_char *cp;

	/*
	* Use virtual circuit;
	* at most one attempt per server.
	*/
	try = _res.retry;
	truncated = 0;
	if (s < 0 \|\| !vc \|\| hp->opcode == ns_o_update) {
	if (s >= 0)
	res_close();

	s = socket(PF_INET, SOCK_STREAM, 0);
	if (s < 0) {
	terrno = errno;
	Perror(stderr, "socket(vc)", errno);
	return (-1);
	}
	errno = 0;
	nsap->sin_len = sizeof ( *nsap );
	if (connect(s, (struct sockaddr *)nsap,
	sizeof *nsap) < 0) {
	terrno = errno;
	Aerror(stderr, "connect/vc",
	errno, *nsap);
	badns \|= (1 << ns);
	res_close();
	goto next_ns;
	}
	vc = 1;
	}
	/*
	* Send length & message
	*/
	putshort((u_short)buflen, (u_char*)&len);
	iov[0].iov_base = (caddr_t)&len;
	iov[0].iov_len = INT16SZ;
	iov[1].iov_base = (caddr_t)buf;
	iov[1].iov_len = buflen;
	if (writev(s, iov, 2) != (INT16SZ + buflen)) {
	terrno = errno;
	Perror(stderr, "write failed", errno);
	badns \|= (1 << ns);
	res_close();
	goto next_ns;
	}
	/*
	* Receive length & response
	*/
	read_len:
	cp = ans;
	len = INT16SZ;
	while ((n = read(s, (char *)cp, (int)len)) > 0) {
	cp += n;
	len = (u_short)( len - n );
	if (len <= 0)
	break;
	}
	if (n <= 0) {
	terrno = errno;
	Perror(stderr, "read failed", errno);
	res_close();
	/*
	* A long running process might get its TCP
	* connection reset if the remote server was
	* restarted. Requery the server instead of
	* trying a new one. When there is only one
	* server, this means that a query might work
	* instead of failing. We only allow one reset
	* per query to prevent looping.
	*/
	if (terrno == ECONNRESET && !connreset) {
	connreset = 1;
	res_close();
	goto same_ns;
	}
	res_close();
	goto next_ns;
	}
	resplen = ns_get16(ans);
	if (resplen > anssiz) {
	Dprint(_res.options & RES_DEBUG,
	(stdout, ";; response truncated\n")
	);
	truncated = 1;
	len = (ushort)anssiz;
	} else
	len = (ushort)resplen;
	if (len < HFIXEDSZ) {
	/*
	* Undersized message.
	*/
	Dprint(_res.options & RES_DEBUG,
	(stdout, ";; undersized: %d\n", len));
	terrno = EMSGSIZE;
	badns \|= (1 << ns);
	res_close();
	goto next_ns;
	}
	cp = ans;
	while (len != 0 &&
	(n = read(s, (char *)cp, (int)len)) > 0) {
	cp += n;
	len = (u_short)( len - n );
	}
	if (n <= 0) {
	terrno = errno;
	Perror(stderr, "read(vc)", errno);
	res_close();
	goto next_ns;
	}
	if (truncated) {
	/*
	* Flush rest of answer
	* so connection stays in synch.
	*/
	anhp->tc = 1;
	len = (ushort)( resplen - anssiz );
	while (len != 0) {
	char junk[PACKETSZ];

	n = (len > sizeof(junk)
	? sizeof(junk)
	: len);
	if ((n = read(s, junk, n)) > 0)
	len = (u_short)( len - n );
	else
	break;
	}
	}
	/*
	* The calling applicating has bailed out of
	* a previous call and failed to arrange to have
	* the circuit closed or the server has got
	* itself confused. Anyway drop the packet and
	* wait for the correct one.
	*/
	if (hp->id != anhp->id) {
	DprintQ((_res.options & RES_DEBUG) \|\|
	(_res.pfcode & RES_PRF_REPLY),
	(stdout, ";; old answer (unexpected):\n"),
	ans, (resplen>anssiz)?anssiz:resplen);
	goto read_len;
	}
	} else {
	/*
	* Use datagrams.
	*/
	#ifndef NOPOLL
	struct pollfd pfd;
	int msec;
	#endif
	struct timeval timeout;
	fd_set dsmask, *dsmaskp;
	int dsmasklen;
	struct sockaddr_in from;
	int fromlen;

	if ((s < 0) \|\| vc) {
	if (vc)
	res_close();
	s = socket(PF_INET, SOCK_DGRAM, 0);
	if (s < 0) {
	#ifndef CAN_RECONNECT
	bad_dg_sock:
	#endif
	terrno = errno;
	Perror(stderr, "socket(dg)", errno);
	return (-1);
	}
	connected = 0;
	}
	#ifndef CANNOT_CONNECT_DGRAM
	/*
	* On a 4.3BSD+ machine (client and server,
	* actually), sending to a nameserver datagram
	* port with no nameserver will cause an
	* ICMP port unreachable message to be returned.
	* If our datagram socket is "connected" to the
	* server, we get an ECONNREFUSED error on the next
	* socket operation, and select returns if the
	* error message is received. We can thus detect
	* the absence of a nameserver without timing out.
	* If we have sent queries to at least two servers,
	* however, we don't want to remain connected,
	* as we wish to receive answers from the first
	* server to respond.
	*/
	if (_res.nscount == 1 \|\| (try == 0 && ns == 0)) {
	/*
	* Connect only if we are sure we won't
	* receive a response from another server.
	*/
	if (!connected) {
	nsap->sin_len = sizeof ( *nsap );
	if (connect(s, (struct sockaddr *)nsap,
	sizeof *nsap
	) < 0) {
	Aerror(stderr,
	"connect(dg)",
	errno, *nsap);
	badns \|= (1 << ns);
	res_close();
	goto next_ns;
	}
	connected = 1;
	}
	if (send(s, (char*)buf, buflen, 0) != buflen) {
	Perror(stderr, "send", errno);
	badns \|= (1 << ns);
	res_close();
	goto next_ns;
	}
	} else {
	/*
	* Disconnect if we want to listen
	* for responses from more than one server.
	*/
	if (connected) {
	#ifdef CAN_RECONNECT
	struct sockaddr_in no_addr;

	no_addr.sin_family = AF_INET;
	no_addr.sin_addr.s_addr = INADDR_ANY;
	no_addr.sin_port = 0;
	(void) connect(s,
	(struct sockaddr *)
	&no_addr,
	sizeof no_addr);
	#else
	int s1 = socket(PF_INET, SOCK_DGRAM,0);
	if (s1 < 0)
	goto bad_dg_sock;
	(void) dup2(s1, s);
	(void) close(s1);
	Dprint(_res.options & RES_DEBUG,
	(stdout, ";; new DG socket\n"))
	#endif /* CAN_RECONNECT */
	connected = 0;
	errno = 0;
	}
	#endif /* !CANNOT_CONNECT_DGRAM */
	if (sendto(s, (char*)buf, buflen, 0,
	(struct sockaddr *)nsap,
	sizeof *nsap)
	!= buflen) {
	Aerror(stderr, "sendto", errno, *nsap);
	badns \|= (1 << ns);
	res_close();
	goto next_ns;
	}
	#ifndef CANNOT_CONNECT_DGRAM
	}
	#endif /* !CANNOT_CONNECT_DGRAM */

	/*
	* Wait for reply
	*/
	#ifndef NOPOLL
	othersyscall:
	if (use_poll) {
	msec = (_res.retrans << try) * 1000;
	if (try > 0)
	msec /= _res.nscount;
	if (msec <= 0)
	msec = 1000;
	} else {
	#endif
	timeout.tv_sec = (_res.retrans << try);
	if (try > 0)
	timeout.tv_sec /= _res.nscount;
	if ((long) timeout.tv_sec <= 0)
	timeout.tv_sec = 1;
	timeout.tv_usec = 0;
	#ifndef NOPOLL
	}
	#endif
	wait:
	if (s < 0) {
	Perror(stderr, "s out-of-bounds", EMFILE);
	res_close();
	goto next_ns;
	}
	#ifndef NOPOLL
	if (use_poll) {
	struct sigaction sa, osa;
	int sigsys_installed = 0;

	pfd.fd = s;
	pfd.events = POLLIN;
	if (use_poll == 1) {
	bzero(&sa, sizeof(sa));
	sa.sa_handler = SIG_IGN;
	if (sigaction(SIGSYS, &sa, &osa) >= 0)
	sigsys_installed = 1;
	}
	n = poll(&pfd, 1, msec);
	if (sigsys_installed == 1) {
	int oerrno = errno;
	sigaction(SIGSYS, &osa, NULL);
	errno = oerrno;
	}
	/* XXX why does nosys() return EINVAL? */
	if (n < 0 && (errno == ENOSYS \|\|
	errno == EINVAL)) {
	use_poll = 0;
	goto othersyscall;
	} else if (use_poll == 1)
	use_poll = 2;
	if (n < 0) {
	if (errno == EINTR)
	goto wait;
	Perror(stderr, "poll", errno);
	res_close();
	goto next_ns;
	}
	} else {
	#endif
	dsmasklen = howmany(s + 1, NFDBITS) *
	sizeof(fd_mask);
	if (dsmasklen > sizeof(fd_set)) {
	dsmaskp = (fd_set *)malloc(dsmasklen);
	if (dsmaskp == NULL) {
	res_close();
	goto next_ns;
	}
	} else
	dsmaskp = &dsmask;
	/* only zero what we need */
	memset((char *)dsmaskp, 0, dsmasklen);
	FD_SET(s, dsmaskp);
	n = select(s + 1, dsmaskp, (fd_set *)NULL,
	(fd_set *)NULL, &timeout);
	if (dsmaskp != &dsmask)
	free(dsmaskp);
	if (n < 0) {
	if (errno == EINTR)
	goto wait;
	Perror(stderr, "select", errno);
	res_close();
	goto next_ns;
	}
	#ifndef NOPOLL
	}
	#endif

	if (n == 0) {
	/*
	* timeout
	*/
	Dprint(_res.options & RES_DEBUG,
	(stdout, ";; timeout\n"));
	gotsomewhere = 1;
	res_close();
	goto next_ns;
	}
	errno = 0;
	fromlen = sizeof(struct sockaddr_in);
	resplen = (int)recvfrom(s, (char*)ans, anssiz, 0,
	(struct sockaddr )&from, (socklen_t )&fromlen);
	if (resplen <= 0) {
	Perror(stderr, "recvfrom", errno);
	res_close();
	goto next_ns;
	}
	gotsomewhere = 1;
	if (resplen < HFIXEDSZ) {
	/*
	* Undersized message.
	*/
	Dprint(_res.options & RES_DEBUG,
	(stdout, ";; undersized: %d\n",
	resplen));
	terrno = EMSGSIZE;
	badns \|= (1 << ns);
	res_close();
	goto next_ns;
	}
	if (hp->id != anhp->id) {
	/*
	* response from old query, ignore it.
	* XXX - potential security hazard could
	* be detected here.
	*/
	DprintQ((_res.options & RES_DEBUG) \|\|
	(_res.pfcode & RES_PRF_REPLY),
	(stdout, ";; old answer:\n"),
	ans, (resplen>anssiz)?anssiz:resplen);
	goto wait;
	}
	#ifdef CHECK_SRVR_ADDR
	if (!(_res.options & RES_INSECURE1) &&
	!res_isourserver(&from)) {
	/*
	* response from wrong server? ignore it.
	* XXX - potential security hazard could
	* be detected here.
	*/
	DprintQ((_res.options & RES_DEBUG) \|\|
	(_res.pfcode & RES_PRF_REPLY),
	(stdout, ";; not our server:\n"),
	ans, (resplen>anssiz)?anssiz:resplen);
	goto wait;
	}
	#endif
	if (!(_res.options & RES_INSECURE2) &&
	!res_queriesmatch(buf, buf + buflen,
	ans, ans + anssiz)) {
	/*
	* response contains wrong query? ignore it.
	* XXX - potential security hazard could
	* be detected here.
	*/
	DprintQ((_res.options & RES_DEBUG) \|\|
	(_res.pfcode & RES_PRF_REPLY),
	(stdout, ";; wrong query name:\n"),
	ans, (resplen>anssiz)?anssiz:resplen);
	goto wait;
	}
	if (anhp->rcode == SERVFAIL \|\|
	anhp->rcode == NOTIMP \|\|
	anhp->rcode == REFUSED) {
	DprintQ(_res.options & RES_DEBUG,
	(stdout, "server rejected query:\n"),
	ans, (resplen>anssiz)?anssiz:resplen);
	badns \|= (1 << ns);
	res_close();
	/* don't retry if called from dig */
	if (!_res.pfcode)
	goto next_ns;
	}
	if (!(_res.options & RES_IGNTC) && anhp->tc) {
	/*
	* get rest of answer;
	* use TCP with same server.
	*/
	Dprint(_res.options & RES_DEBUG,
	(stdout, ";; truncated answer\n"));
	v_circuit = 1;
	res_close();
	goto same_ns;
	}
	} /if vc/dg/
	Dprint((_res.options & RES_DEBUG) \|\|
	((_res.pfcode & RES_PRF_REPLY) &&
	(_res.pfcode & RES_PRF_HEAD1)),
	(stdout, ";; got answer:\n"));
	if((_res.options & RES_DEBUG) \|\|
	(_res.pfcode & RES_PRF_REPLY)) {
	__fp_nquery(ans, (resplen>anssiz)?anssiz:resplen, stdout);
	}
	/*
	* If using virtual circuits, we assume that the first server
	* is preferred over the rest (i.e. it is on the local
	* machine) and only keep that one open.
	* If we have temporarily opened a virtual circuit,
	* or if we haven't been asked to keep a socket open,
	* close the socket.
	*/
	if ((v_circuit && (!(_res.options & RES_USEVC) \|\| ns != 0)) \|\|
	!(_res.options & RES_STAYOPEN)) {
	res_close();
	}
	if (Rhook) {
	int done = 0, loops = 0;

	do {
	res_sendhookact act;

	act = (*Rhook)(nsap, buf, buflen,
	ans, anssiz, &resplen);
	switch (act) {
	case res_goahead:
	case res_done:
	done = 1;
	break;
	case res_nextns:
	res_close();
	goto next_ns;
	case res_modified:
	/* give the hook another try */
	if (++loops < 42) /doug adams/
	break;
	/FALLTHROUGH/
	case res_error:
	/FALLTHROUGH/
	default:
	return (-1);
	}
	} while (!done);

	}
	return (resplen);
	next_ns: ;
	} /foreach ns/
	} /foreach retry/
	res_close();
	if (!v_circuit) {
	if (!gotsomewhere)
	errno = ECONNREFUSED; /* no nameservers found */
	else
	errno = ETIMEDOUT; /* no answer obtained */
	} else
	errno = terrno;
	return (-1);
	}

	/*
	* This routine is for closing the socket if a virtual circuit is used and
	* the program wants to close it. This provides support for endhostent()
	* which expects to close the socket.
	*
	* This routine is not expected to be user visible.
	*/
	void
	res_close()
	{
	if (s >= 0) {
	(void) close(s);
	s = -1;
	connected = 0;
	vc = 0;
	}
	}