Sigh, back out the last bright idea I had here about compiling the res_*

routines from contrib/bind directly.  There were too many problems,
including having to add -DUSE_OPTIONS_H to the entire libc source in
order for the contrib code to pick up it's options, and so on.

Instead, I've merged the changes, libc is now self contained again.

1 files changed, 741 insertions, 0 deletions

diff --git a/lib/libc/net/res_send.c b/lib/libc/net/res_send.c
new file mode 100644
index 0000000..dcb0220
--- /dev/null
+++ b/lib/libc/net/res_send.c
@@ -0,0 +1,741 @@
+/*
+ * ++Copyright++ 1985, 1989, 1993
+ * -
+ * Copyright (c) 1985, 1989, 1993
+ *    The Regents of the University of California.  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 and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * -
+ * 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.
+ * -
+ * --Copyright--
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)res_send.c	8.1 (Berkeley) 6/4/93";
+static char rcsid[] = "$Id: res_send.c,v 8.9 1996/08/05 08:31:35 vixie 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/time.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include "res_config.h"
+#include <arpa/nameser.h>
+
+#include <stdio.h>
+#include <netdb.h>
+#include <errno.h>
+#include <resolv.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+void _res_close __P((void));
+
+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 ciruit? */
+
+#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, string, error, address)
+	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, string, error)
+	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
+
+static res_send_qhook Qhook = NULL;
+static res_send_rhook Rhook = NULL;
+
+void
+res_send_setqhook(hook)
+	res_send_qhook hook;
+{
+
+	Qhook = hook;
+}
+
+void
+res_send_setrhook(hook)
+	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(inp)
+	const struct sockaddr_in *inp;
+{
+	struct sockaddr_in ina;
+	register int ns, ret;
+
+	ina = *inp;
+	ret = 0;
+	for (ns = 0;  ns < _res.nscount;  ns++) {
+		register 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)
+ * returns:
+ *	-1 : format error
+ *	0  : not found
+ *	>0 : found
+ * author:
+ *	paul vixie, 29may94
+ */
+int
+res_nameinquery(name, type, class, buf, eom)
+	const char *name;
+	register int type, class;
+	const u_char *buf, *eom;
+{
+	register const u_char *cp = buf + HFIXEDSZ;
+	int qdcount = ntohs(((HEADER*)buf)->qdcount);
+
+	while (qdcount-- > 0) {
+		char tname[MAXDNAME+1];
+		register int n, ttype, tclass;
+
+		n = dn_expand(buf, eom, cp, tname, sizeof tname);
+		if (n < 0)
+			return (-1);
+		cp += n;
+		ttype = _getshort(cp); cp += INT16SZ;
+		tclass = _getshort(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(buf1, eom1, buf2, eom2)
+	const u_char *buf1, *eom1;
+	const u_char *buf2, *eom2;
+{
+	register const u_char *cp = buf1 + HFIXEDSZ;
+	int qdcount = ntohs(((HEADER*)buf1)->qdcount);
+
+	if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
+		return (0);
+	while (qdcount-- > 0) {
+		char tname[MAXDNAME+1];
+		register int n, ttype, tclass;
+
+		n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
+		if (n < 0)
+			return (-1);
+		cp += n;
+		ttype = _getshort(cp);	cp += INT16SZ;
+		tclass = _getshort(cp); cp += INT16SZ;
+		if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
+			return (0);
+	}
+	return (1);
+}
+
+int
+res_send(buf, buflen, ans, anssiz)
+	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;
+	register int n;
+	u_int badns;	/* XXX NSMAX can't exceed #/bits in this var */
+
+	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+		/* errno should have been set by res_init() in this case. */
+		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)) {
+				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;
+				if (connect(s, (struct sockaddr *)nsap,
+					    sizeof(struct sockaddr)) < 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;
+				if ((len -= n) <= 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 = _getshort(ans);
+			if (resplen > anssiz) {
+				Dprint(_res.options & RES_DEBUG,
+				       (stdout, ";; response truncated\n")
+				       );
+				truncated = 1;
+				len = anssiz;
+			} else
+				len = resplen;
+			cp = ans;
+			while (len != 0 &&
+			       (n = read(s, (char *)cp, (int)len)) > 0) {
+				cp += n;
+				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 = resplen - anssiz;
+				while (len != 0) {
+					char junk[PACKETSZ];
+
+					n = (len > sizeof(junk)
+					     ? sizeof(junk)
+					     : len);
+					if ((n = read(s, junk, n)) > 0)
+						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.
+			 */
+			struct timeval timeout;
+			fd_set dsmask;
+			struct sockaddr_in from;
+			int fromlen;
+
+			if ((s < 0) || vc) {
+				if (vc)
+					_res_close();
+				s = socket(PF_INET, SOCK_DGRAM, 0);
+				if (s < 0) {
+					terrno = errno;
+					Perror(stderr, "socket(dg)", errno);
+					return (-1);
+				}
+				connected = 0;
+			}
+			/*
+			 * 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) {
+					if (connect(s, (struct sockaddr *)nsap,
+						    sizeof(struct sockaddr)
+						    ) < 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) {
+					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));
+					connected = 0;
+					errno = 0;
+				}
+				if (sendto(s, (char*)buf, buflen, 0,
+					   (struct sockaddr *)nsap,
+					   sizeof(struct sockaddr))
+				    != buflen) {
+					Aerror(stderr, "sendto", errno, *nsap);
+					badns |= (1 << ns);
+					_res_close();
+					goto next_ns;
+				}
+			}
+
+			/*
+			 * Wait for reply
+			 */
+			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;
+    wait:
+			FD_ZERO(&dsmask);
+			FD_SET(s, &dsmask);
+			n = select(s+1, &dsmask, (fd_set *)NULL,
+				   (fd_set *)NULL, &timeout);
+			if (n < 0) {
+				if (errno == EINTR)
+					goto wait;
+				Perror(stderr, "select", errno);
+				_res_close();
+				goto next_ns;
+			}
+			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 = recvfrom(s, (char*)ans, anssiz, 0,
+					   (struct sockaddr *)&from, &fromlen);
+			if (resplen <= 0) {
+				Perror(stderr, "recvfrom", errno);
+				_res_close();
+				goto next_ns;
+			}
+			gotsomewhere = 1;
+			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;
+			}
+#if 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"));
+		DprintQ((_res.options & RES_DEBUG) ||
+			(_res.pfcode & RES_PRF_REPLY),
+			(stdout, ""),
+			ans, (resplen>anssiz)?anssiz:resplen);
+		/*
+		 * 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;
+	}
+}