StdLib/BsdSocketLib/gethostbydns.c - third_party/edk2 - Git at Google

 /*
  * ++Copyright++ 1985, 1988, 1993
  * -
  * Copyright (c) 1985, 1988, 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--
  */

 /*
  * 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 Intel Corporation and
  *    its contributors.
  *
  * 4. Neither the name of Intel Corporation or its contributors may be
  *    used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY 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 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.
  *
  */

 #if defined(LIBC_SCCS) && !defined(lint)
 static char sccsid[] = "@(#)gethostnamadr.c	8.1 (Berkeley) 6/4/93";
 static char fromrcsid[] = "From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $";
 static char rcsid[] = "$Id: gethostbydns.c,v 1.1.1.1 2003/11/19 01:51:27 kyu3 Exp $";
 #endif /* LIBC_SCCS and not lint */

 #include <sys/types.h>
 #include <sys/param.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <arpa/nameser.h>

 #include <stdio.h>
 #include <unistd.h>
 #include <string.h>
 #include <netdb.h>
 #include <resolv.h>
 #include <ctype.h>
 #include <errno.h>
 #ifdef _ORG_FREEBSD_
 #include <syslog.h>
 #else
 #include <stdlib.h>
 u_int32_t _getlong(const u_char *src);
 u_int16_t _getshort(const u_char *src);
 #endif

 #include "res_config.h"
 #include "Socklib_internals.h"

 #define SPRINTF(x) ((size_t)sprintf x)

 #define	MAXALIASES	35
 #define	MAXADDRS	35

 #ifdef _ORG_FREEBSD_
 static const char AskedForGot[] =
 		"gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
 #endif

 static char *h_addr_ptrs[MAXADDRS + 1];

 static struct hostent host;
 static char *host_aliases[MAXALIASES];
 static char hostbuf[8*1024];
 static u_char host_addr[16];	/* IPv4 or IPv6 */

 #ifdef RESOLVSORT
 static void addrsort(char **, int);
 #endif

 #if PACKETSZ > 1024
 #define	MAXPACKET	PACKETSZ
 #else
 #define	MAXPACKET	1024
 #endif

 typedef union {
     HEADER hdr;
     u_char buf[MAXPACKET];
 } querybuf;

 typedef union {
     int32_t al;
     char ac;
 } align;

 extern int h_errno;
 int _dns_ttl_;

 #ifdef DEBUG_RES
 static void
 dprintf(char *msg, int num)
 {
 	if (_res.options & RES_DEBUG) {
 		int save = errno;

 		printf(msg, num);
 		errno = save;
 	}
 }
 #else
 # define dprintf(msg, num) /*nada*/
 #endif

 #define BOUNDED_INCR(x) \
 	do { \
 		cp += x; \
 		if (cp > eom) { \
 			h_errno = NO_RECOVERY; \
 			return (NULL); \
 		} \
 	} while (0)

 #define BOUNDS_CHECK(ptr, count) \
 	do { \
 		if ((ptr) + (count) > eom) { \
 			h_errno = NO_RECOVERY; \
 			return (NULL); \
 		} \
 	} while (0)

 static struct hostent *
 gethostanswer(const querybuf *answer, int anslen, const char *qname, int qtype)
 {
 	register const HEADER *hp;
 	register const u_char *cp;
 	register int n;
 	const u_char *eom, *erdata;
 	char *bp, **ap, **hap;
 	int type, class, buflen, ancount, qdcount;
 	int haveanswer, had_error;
 	int toobig = 0;
 	char tbuf[MAXDNAME];
 	const char *tname;
 	int (*name_ok)(const char *);

 	tname = qname;
 	host.h_name = NULL;
 	eom = answer->buf + anslen;
 	switch (qtype) {
 	case T_A:
 	case T_AAAA:
 		name_ok = res_hnok;
 		break;
 	case T_PTR:
 		name_ok = res_dnok;
 		break;
 	default:
 		h_errno = NO_RECOVERY;
 		return (NULL);	/* XXX should be abort(); */
 	}
 	/*
 	 * find first satisfactory answer
 	 */
 	hp = &answer->hdr;
 	ancount = ntohs(hp->ancount);
 	qdcount = ntohs(hp->qdcount);
 	bp = hostbuf;
 	buflen = sizeof hostbuf;
 	cp = answer->buf;
 	BOUNDED_INCR(HFIXEDSZ);
 	if (qdcount != 1) {
 		h_errno = NO_RECOVERY;
 		return (NULL);
 	}
 	n = dn_expand(answer->buf, eom, cp, bp, buflen);
 	if ((n < 0) || !(*name_ok)(bp)) {
 		h_errno = NO_RECOVERY;
 		return (NULL);
 	}
 	BOUNDED_INCR(n + QFIXEDSZ);
 	if (qtype == T_A || qtype == T_AAAA) {
 		/* res_send() has already verified that the query name is the
 		 * same as the one we sent; this just gets the expanded name
 		 * (i.e., with the succeeding search-domain tacked on).
 		 */
 		n = (int)strlen(bp) + 1;		/* for the \0 */
 		if (n >= MAXHOSTNAMELEN) {
 			h_errno = NO_RECOVERY;
 			return (NULL);
 		}
 		host.h_name = bp;
 		bp += n;
 		buflen -= n;
 		/* The qname can be abbreviated, but h_name is now absolute. */
 		qname = host.h_name;
 	}
 	ap = host_aliases;
 	*ap = NULL;
 	host.h_aliases = host_aliases;
 	hap = h_addr_ptrs;
 	*hap = NULL;
 	host.h_addr_list = h_addr_ptrs;
 	haveanswer = 0;
 	had_error = 0;
 	_dns_ttl_ = -1;
 	while (ancount-- > 0 && cp < eom && !had_error) {
 		n = dn_expand(answer->buf, eom, cp, bp, buflen);
 		if ((n < 0) || !(*name_ok)(bp)) {
 			had_error++;
 			continue;
 		}
 		cp += n;			/* name */
 		BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 		type = _getshort(cp);
  		cp += INT16SZ;			/* type */
 		class = _getshort(cp);
  		cp += INT16SZ;			/* class */
 		if (qtype == T_A  && type == T_A)
 			_dns_ttl_ = _getlong(cp);
 		cp += INT32SZ;			/* TTL */
 		n = _getshort(cp);
 		cp += INT16SZ;			/* len */
 		BOUNDS_CHECK(cp, n);
 		erdata = cp + n;
 		if (class != C_IN) {
 			/* XXX - debug? syslog? */
 			cp += n;
 			continue;		/* XXX - had_error++ ? */
 		}
 		if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 			if (ap >= &host_aliases[MAXALIASES-1])
 				continue;
 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 			if ((n < 0) || !(*name_ok)(tbuf)) {
 				had_error++;
 				continue;
 			}
 			cp += n;
 			if (cp != erdata) {
 				h_errno = NO_RECOVERY;
 				return (NULL);
 			}
 			/* Store alias. */
 			*ap++ = bp;
 			n = (int)strlen(bp) + 1;	/* for the \0 */
 			if (n >= MAXHOSTNAMELEN) {
 				had_error++;
 				continue;
 			}
 			bp += n;
 			buflen -= n;
 			/* Get canonical name. */
 			n = (int)strlen(tbuf) + 1;	/* for the \0 */
 			if (n > buflen || n >= MAXHOSTNAMELEN) {
 				had_error++;
 				continue;
 			}
 			strcpy(bp, tbuf);
 			host.h_name = bp;
 			bp += n;
 			buflen -= n;
 			continue;
 		}
 		if (qtype == T_PTR && type == T_CNAME) {
 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 			if (n < 0 || !res_dnok(tbuf)) {
 				had_error++;
 				continue;
 			}
 			cp += n;
 			if (cp != erdata) {
 				h_errno = NO_RECOVERY;
 				return (NULL);
 			}
 			/* Get canonical name. */
 			n = (int)strlen(tbuf) + 1;	/* for the \0 */
 			if (n > buflen || n >= MAXHOSTNAMELEN) {
 				had_error++;
 				continue;
 			}
 			strcpy(bp, tbuf);
 			tname = bp;
 			bp += n;
 			buflen -= n;
 			continue;
 		}
 		if (type != qtype) {
 #ifdef _ORG_FREEBSD_
 			syslog(LOG_NOTICE|LOG_AUTH,
 	"gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
 			       qname, p_class(C_IN), p_type(qtype),
 			       p_type(type));
 #endif
 			cp += n;
 			continue;		/* XXX - had_error++ ? */
 		}
 		switch (type) {
 		case T_PTR:
 			if (strcasecmp(tname, bp) != 0) {
 #ifdef _ORG_FREEBSD_
 				syslog(LOG_NOTICE|LOG_AUTH,
 				       AskedForGot, qname, bp);
 #endif
 				cp += n;
 				continue;	/* XXX - had_error++ ? */
 			}
 			n = dn_expand(answer->buf, eom, cp, bp, buflen);
 			if ((n < 0) || !res_hnok(bp)) {
 				had_error++;
 				break;
 			}
 #if MULTI_PTRS_ARE_ALIASES
 			cp += n;
 			if (cp != erdata) {
 				h_errno = NO_RECOVERY;
 				return (NULL);
 			}
 			if (!haveanswer)
 				host.h_name = bp;
 			else if (ap < &host_aliases[MAXALIASES-1])
 				*ap++ = bp;
 			else
 				n = -1;
 			if (n != -1) {
 				n = (int)strlen(bp) + 1;	/* for the \0 */
 				if (n >= MAXHOSTNAMELEN) {
 					had_error++;
 					break;
 				}
 				bp += n;
 				buflen -= n;
 			}
 			break;
 #else
 			host.h_name = bp;
 			if (_res.options & RES_USE_INET6) {
 				n = strlen(bp) + 1;	/* for the \0 */
 				if (n >= MAXHOSTNAMELEN) {
 					had_error++;
 					break;
 				}
 				bp += n;
 				buflen -= n;
 				_map_v4v6_hostent(&host, &bp, &buflen);
 			}
 			h_errno = NETDB_SUCCESS;
 			return (&host);
 #endif
 		case T_A:
 		case T_AAAA:
 			if (strcasecmp(host.h_name, bp) != 0) {
 #ifdef _ORG_FREEBSD_
 				syslog(LOG_NOTICE|LOG_AUTH,
 				       AskedForGot, host.h_name, bp);
 #endif
 				cp += n;
 				continue;	/* XXX - had_error++ ? */
 			}
 			if (n != host.h_length) {
 				cp += n;
 				continue;
 			}
 			if (!haveanswer) {
 				register int nn;

 				host.h_name = bp;
 				nn = (int)strlen(bp) + 1;	/* for the \0 */
 				bp += nn;
 				buflen -= nn;
 			}

 			bp += sizeof(align) - ((size_t)bp % sizeof(align));

 			if (bp + n >= &hostbuf[sizeof hostbuf]) {
 				dprintf("size (%d) too big\n", n);
 				had_error++;
 				continue;
 			}
 			if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 				if (!toobig++)
 					dprintf("Too many addresses (%d)\n",
 						MAXADDRS);
 				cp += n;
 				continue;
 			}
       *hap++ = bp;
 			bcopy(cp, bp, n);
 			bp += n;
 			buflen -= n;
 			cp += n;
 			if (cp != erdata) {
 				h_errno = NO_RECOVERY;
 				return (NULL);
 			}
 			break;
 		default:
 			dprintf("Impossible condition (type=%d)\n", type);
 			h_errno = NO_RECOVERY;
 			return (NULL);
 			/* BIND has abort() here, too risky on bad data */
 		}
 		if (!had_error)
 			haveanswer++;
 	}
 	if (haveanswer) {
 		*ap = NULL;
 		*hap = NULL;
 # if defined(RESOLVSORT)
 		/*
 		 * Note: we sort even if host can take only one address
 		 * in its return structures - should give it the "best"
 		 * address in that case, not some random one
 		 */
 		if (_res.nsort && haveanswer > 1 && qtype == T_A)
 			addrsort(h_addr_ptrs, haveanswer);
 # endif /*RESOLVSORT*/
 		if (!host.h_name) {
 			n = (int)strlen(qname) + 1;	/* for the \0 */
 			if (n > buflen || n >= MAXHOSTNAMELEN)
 				goto no_recovery;
 			strcpy(bp, qname);
 			host.h_name = bp;
 			bp += n;
 			buflen -= n;
 		}
 		if (_res.options & RES_USE_INET6)
 			_map_v4v6_hostent(&host, &bp, &buflen);
 		h_errno = NETDB_SUCCESS;
 		return (&host);
 	}
  no_recovery:
 	h_errno = NO_RECOVERY;
 	return (NULL);
 }

 struct hostent *
 __dns_getanswer(const char *answer, int anslen, const char *qname, int qtype)
 {
 	switch(qtype) {
 	case T_AAAA:
 		host.h_addrtype = AF_INET6;
 		host.h_length = IN6ADDRSZ;
 		break;
 	case T_A:
 	default:
 		host.h_addrtype = AF_INET;
 		host.h_length = INADDRSZ;
 		break;
 	}

 	return(gethostanswer((const querybuf *)answer, anslen, qname, qtype));
 }

 struct hostent *
 _gethostbydnsname(const char *name, int af)
 {
 	querybuf buf;
 	register const char *cp;
 	char *bp;
 	int n, size, type, len;

 	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
 		return (NULL);
 	}

 	switch (af) {
 	case AF_INET:
 		size = INADDRSZ;
 		type = T_A;
 		break;
 	case AF_INET6:
 		size = IN6ADDRSZ;
 		type = T_AAAA;
 		break;
 	default:
 		h_errno = NETDB_INTERNAL;
 		errno = EAFNOSUPPORT;
 		return (NULL);
 	}

 	host.h_addrtype = af;
 	host.h_length = size;

 	/*
 	 * if there aren't any dots, it could be a user-level alias.
 	 * this is also done in res_query() since we are not the only
 	 * function that looks up host names.
 	 */
 	if (!strchr(name, '.') && ( NULL != (cp = __hostalias(name))))
 		name = cp;

 	/*
 	 * disallow names consisting only of digits/dots, unless
 	 * they end in a dot.
 	 */
 	if (isdigit(name[0]))
 		for (cp = name;; ++cp) {
 			if (!*cp) {
 				if (*--cp == '.')
 					break;
 				/*
 				 * All-numeric, no dot at the end.
 				 * Fake up a hostent as if we'd actually
 				 * done a lookup.
 				 */
 				if (inet_pton(af, name, host_addr) <= 0) {
 					h_errno = HOST_NOT_FOUND;
 					return (NULL);
 				}
 				strncpy(hostbuf, name, MAXDNAME);
 				hostbuf[MAXDNAME] = '\0';
 				bp = hostbuf + MAXDNAME;
 				len = sizeof hostbuf - MAXDNAME;
 				host.h_name = hostbuf;
 				host.h_aliases = host_aliases;
 				host_aliases[0] = NULL;
 				h_addr_ptrs[0] = (char *)host_addr;
 				h_addr_ptrs[1] = NULL;
 				host.h_addr_list = h_addr_ptrs;
 				if (_res.options & RES_USE_INET6)
 					_map_v4v6_hostent(&host, &bp, &len);
 				h_errno = NETDB_SUCCESS;
 				return (&host);
 			}
 			if (!isdigit(*cp) && *cp != '.')
 				break;
 		}
 	if ((isxdigit(name[0]) && strchr(name, ':') != NULL) ||
 	    name[0] == ':')
 		for (cp = name;; ++cp) {
 			if (!*cp) {
 				if (*--cp == '.')
 					break;
 				/*
 				 * All-IPv6-legal, no dot at the end.
 				 * Fake up a hostent as if we'd actually
 				 * done a lookup.
 				 */
 				if (inet_pton(af, name, host_addr) <= 0) {
 					h_errno = HOST_NOT_FOUND;
 					return (NULL);
 				}
 				strncpy(hostbuf, name, MAXDNAME);
 				hostbuf[MAXDNAME] = '\0';
 				bp = hostbuf + MAXDNAME;
 				len = sizeof hostbuf - MAXDNAME;
 				host.h_name = hostbuf;
 				host.h_aliases = host_aliases;
 				host_aliases[0] = NULL;
 				h_addr_ptrs[0] = (char *)host_addr;
 				h_addr_ptrs[1] = NULL;
 				host.h_addr_list = h_addr_ptrs;
 				h_errno = NETDB_SUCCESS;
 				return (&host);
 			}
 			if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
 				break;
 		}

 	if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf))) < 0) {
 		dprintf("res_search failed (%d)\n", n);
 		return (NULL);
 	}
 	return (gethostanswer(&buf, n, name, type));
 }

 struct hostent *
 _gethostbydnsaddr(const char *addr, int len, int af)
 {
 	const u_char *uaddr = (const u_char *)addr;
 	static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 	static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 	int n, size;
 	querybuf buf;
 	register struct hostent *hp;
 	char qbuf[MAXDNAME+1], *qp;
 #ifdef SUNSECURITY
 	register struct hostent *rhp;
 	char **haddr;
 	u_long old_options;
 	char hname2[MAXDNAME+1];
 #endif /*SUNSECURITY*/

 	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
 		return (NULL);
 	}
 	if (af == AF_INET6 && len == IN6ADDRSZ &&
 	    (!bcmp(uaddr, mapped, sizeof mapped) ||
 	     !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
 		/* Unmap. */
 		addr += sizeof mapped;
 		uaddr += sizeof mapped;
 		af = AF_INET;
 		len = INADDRSZ;
 	}
 	switch (af) {
 	case AF_INET:
 		size = INADDRSZ;
 		break;
 	case AF_INET6:
 		size = IN6ADDRSZ;
 		break;
 	default:
 		errno = EAFNOSUPPORT;
 		h_errno = NETDB_INTERNAL;
 		return (NULL);
 	}
 	if (size != len) {
 		errno = EINVAL;
 		h_errno = NETDB_INTERNAL;
 		return (NULL);
 	}
 	switch (af) {
 	case AF_INET:
 		(void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 			       (uaddr[3] & 0xff),
 			       (uaddr[2] & 0xff),
 			       (uaddr[1] & 0xff),
 			       (uaddr[0] & 0xff));
 		break;
 	case AF_INET6:
 		qp = qbuf;
 		for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 			qp += SPRINTF((qp, "%x.%x.",
 				       uaddr[n] & 0xf,
 				       (uaddr[n] >> 4) & 0xf));
 		}
 		strcpy(qp, "ip6.int");
 		break;
 	default:
 		abort();
 	}
 	n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
 	if (n < 0) {
 		dprintf("res_query failed (%d)\n", n);
 		return (NULL);
 	}
 	if ( NULL == (hp = gethostanswer(&buf, n, qbuf, T_PTR)))
 		return (NULL);	/* h_errno was set by gethostanswer() */
 #ifdef SUNSECURITY
 	if (af == AF_INET) {
 	    /*
 	     * turn off search as the name should be absolute,
 	     * 'localhost' should be matched by defnames
 	     */
 	    strncpy(hname2, hp->h_name, MAXDNAME);
 	    hname2[MAXDNAME] = '\0';
 	    old_options = _res.options;
 	    _res.options &= ~RES_DNSRCH;
 	    _res.options |= RES_DEFNAMES;
 	    if (!(rhp = gethostbyname(hname2))) {
 #ifdef _ORG_FREEBSD_
 		syslog(LOG_NOTICE|LOG_AUTH,
 		       "gethostbyaddr: No A record for %s (verifying [%s])",
 		       hname2, inet_ntoa(*((struct in_addr *)addr)));
 #endif
 		_res.options = old_options;
 		h_errno = HOST_NOT_FOUND;
 		return (NULL);
 	    }
 	    _res.options = old_options;
 	    for (haddr = rhp->h_addr_list; *haddr; haddr++)
 		if (!memcmp(*haddr, addr, INADDRSZ))
 			break;
 	    if (!*haddr) {
 #ifdef _ORG_FREEBSD_
 		syslog(LOG_NOTICE|LOG_AUTH,
 		       "gethostbyaddr: A record of %s != PTR record [%s]",
 		       hname2, inet_ntoa(*((struct in_addr *)addr)));
 #endif
 		h_errno = HOST_NOT_FOUND;
 		return (NULL);
 	    }
 	}
 #endif /*SUNSECURITY*/
 	hp->h_addrtype = af;
 	hp->h_length = len;
 	bcopy(addr, host_addr, len);
 	h_addr_ptrs[0] = (char *)host_addr;
 	h_addr_ptrs[1] = NULL;
 	if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 		_map_v4v6_address((char*)host_addr, (char*)host_addr);
 		hp->h_addrtype = AF_INET6;
 		hp->h_length = IN6ADDRSZ;
 	}
 	h_errno = NETDB_SUCCESS;
 	return (hp);
 }

 #ifdef RESOLVSORT
 static void
 addrsort(char **ap, int num)
 {
 	short i, j;
 	char **p;
 	short aval[MAXADDRS];
 	short needsort = 0;

 	p = ap;
 	for (i = 0; i < num; i++, p++) {
 	    for (j = 0 ; (unsigned)j < _res.nsort; j++)
 		if (_res.sort_list[j].addr.s_addr ==
 		    (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 			break;
 	    aval[i] = j;
 	    if (needsort == 0 && i > 0 && j < aval[i-1])
 		needsort = i;
 	}
 	if (!needsort)
 	    return;

 	while (needsort < num) {
 	    for (j = needsort - 1; j >= 0; j--) {
 		if (aval[j] > aval[j+1]) {
 		    char *hp;

 		    i = aval[j];
 		    aval[j] = aval[j+1];
 		    aval[j+1] = i;

 		    hp = ap[j];
 		    ap[j] = ap[j+1];
 		    ap[j+1] = hp;

 		} else
 		    break;
 	    }
 	    needsort++;
 	}
 }
 #endif
 void
 _sethostdnsent(int stayopen)
 {
 	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
 		return;
 	if (stayopen)
 		_res.options |= RES_STAYOPEN | RES_USEVC;
 }

 void
 _endhostdnsent()
 {
 	_res.options &= ~(RES_STAYOPEN | RES_USEVC);
 	res_close();
 }
	/*
	* ++Copyright++ 1985, 1988, 1993
	* -
	* Copyright (c) 1985, 1988, 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--
	*/

	/*
	* 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 Intel Corporation and
	* its contributors.
	*
	* 4. Neither the name of Intel Corporation or its contributors may be
	* used to endorse or promote products derived from this software
	* without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY 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 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.
	*
	*/

	#if defined(LIBC_SCCS) && !defined(lint)
	static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93";
	static char fromrcsid[] = "From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $";
	static char rcsid[] = "$Id: gethostbydns.c,v 1.1.1.1 2003/11/19 01:51:27 kyu3 Exp $";
	#endif /* LIBC_SCCS and not lint */

	#include <sys/types.h>
	#include <sys/param.h>
	#include <sys/socket.h>
	#include <netinet/in.h>
	#include <arpa/inet.h>
	#include <arpa/nameser.h>

	#include <stdio.h>
	#include <unistd.h>
	#include <string.h>
	#include <netdb.h>
	#include <resolv.h>
	#include <ctype.h>
	#include <errno.h>
	#ifdef _ORG_FREEBSD_
	#include <syslog.h>
	#else
	#include <stdlib.h>
	u_int32_t _getlong(const u_char *src);
	u_int16_t _getshort(const u_char *src);
	#endif

	#include "res_config.h"
	#include "Socklib_internals.h"

	#define SPRINTF(x) ((size_t)sprintf x)

	#define MAXALIASES 35
	#define MAXADDRS 35

	#ifdef _ORG_FREEBSD_
	static const char AskedForGot[] =
	"gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
	#endif

	static char *h_addr_ptrs[MAXADDRS + 1];

	static struct hostent host;
	static char *host_aliases[MAXALIASES];
	static char hostbuf[8*1024];
	static u_char host_addr[16]; /* IPv4 or IPv6 */

	#ifdef RESOLVSORT
	static void addrsort(char **, int);
	#endif

	#if PACKETSZ > 1024
	#define MAXPACKET PACKETSZ
	#else
	#define MAXPACKET 1024
	#endif

	typedef union {
	HEADER hdr;
	u_char buf[MAXPACKET];
	} querybuf;

	typedef union {
	int32_t al;
	char ac;
	} align;

	extern int h_errno;
	int _dns_ttl_;

	#ifdef DEBUG_RES
	static void
	dprintf(char *msg, int num)
	{
	if (_res.options & RES_DEBUG) {
	int save = errno;

	printf(msg, num);
	errno = save;
	}
	}
	#else
	# define dprintf(msg, num) /nada/
	#endif

	#define BOUNDED_INCR(x) \
	do { \
	cp += x; \
	if (cp > eom) { \
	h_errno = NO_RECOVERY; \
	return (NULL); \
	} \
	} while (0)

	#define BOUNDS_CHECK(ptr, count) \
	do { \
	if ((ptr) + (count) > eom) { \
	h_errno = NO_RECOVERY; \
	return (NULL); \
	} \
	} while (0)

	static struct hostent *
	gethostanswer(const querybuf answer, int anslen, const char qname, int qtype)
	{
	register const HEADER *hp;
	register const u_char *cp;
	register int n;
	const u_char eom, erdata;
	char bp, ap, *hap;
	int type, class, buflen, ancount, qdcount;
	int haveanswer, had_error;
	int toobig = 0;
	char tbuf[MAXDNAME];
	const char *tname;
	int (name_ok)(const char );

	tname = qname;
	host.h_name = NULL;
	eom = answer->buf + anslen;
	switch (qtype) {
	case T_A:
	case T_AAAA:
	name_ok = res_hnok;
	break;
	case T_PTR:
	name_ok = res_dnok;
	break;
	default:
	h_errno = NO_RECOVERY;
	return (NULL); /* XXX should be abort(); */
	}
	/*
	* find first satisfactory answer
	*/
	hp = &answer->hdr;
	ancount = ntohs(hp->ancount);
	qdcount = ntohs(hp->qdcount);
	bp = hostbuf;
	buflen = sizeof hostbuf;
	cp = answer->buf;
	BOUNDED_INCR(HFIXEDSZ);
	if (qdcount != 1) {
	h_errno = NO_RECOVERY;
	return (NULL);
	}
	n = dn_expand(answer->buf, eom, cp, bp, buflen);
	if ((n < 0) \|\| !(*name_ok)(bp)) {
	h_errno = NO_RECOVERY;
	return (NULL);
	}
	BOUNDED_INCR(n + QFIXEDSZ);
	if (qtype == T_A \|\| qtype == T_AAAA) {
	/* res_send() has already verified that the query name is the
	* same as the one we sent; this just gets the expanded name
	* (i.e., with the succeeding search-domain tacked on).
	*/
	n = (int)strlen(bp) + 1; /* for the \0 */
	if (n >= MAXHOSTNAMELEN) {
	h_errno = NO_RECOVERY;
	return (NULL);
	}
	host.h_name = bp;
	bp += n;
	buflen -= n;
	/* The qname can be abbreviated, but h_name is now absolute. */
	qname = host.h_name;
	}
	ap = host_aliases;
	*ap = NULL;
	host.h_aliases = host_aliases;
	hap = h_addr_ptrs;
	*hap = NULL;
	host.h_addr_list = h_addr_ptrs;
	haveanswer = 0;
	had_error = 0;
	_dns_ttl_ = -1;
	while (ancount-- > 0 && cp < eom && !had_error) {
	n = dn_expand(answer->buf, eom, cp, bp, buflen);
	if ((n < 0) \|\| !(*name_ok)(bp)) {
	had_error++;
	continue;
	}
	cp += n; /* name */
	BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
	type = _getshort(cp);
	cp += INT16SZ; /* type */
	class = _getshort(cp);
	cp += INT16SZ; /* class */
	if (qtype == T_A && type == T_A)
	_dns_ttl_ = _getlong(cp);
	cp += INT32SZ; /* TTL */
	n = _getshort(cp);
	cp += INT16SZ; /* len */
	BOUNDS_CHECK(cp, n);
	erdata = cp + n;
	if (class != C_IN) {
	/* XXX - debug? syslog? */
	cp += n;
	continue; /* XXX - had_error++ ? */
	}
	if ((qtype == T_A \|\| qtype == T_AAAA) && type == T_CNAME) {
	if (ap >= &host_aliases[MAXALIASES-1])
	continue;
	n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
	if ((n < 0) \|\| !(*name_ok)(tbuf)) {
	had_error++;
	continue;
	}
	cp += n;
	if (cp != erdata) {
	h_errno = NO_RECOVERY;
	return (NULL);
	}
	/* Store alias. */
	*ap++ = bp;
	n = (int)strlen(bp) + 1; /* for the \0 */
	if (n >= MAXHOSTNAMELEN) {
	had_error++;
	continue;
	}
	bp += n;
	buflen -= n;
	/* Get canonical name. */
	n = (int)strlen(tbuf) + 1; /* for the \0 */
	if (n > buflen \|\| n >= MAXHOSTNAMELEN) {
	had_error++;
	continue;
	}
	strcpy(bp, tbuf);
	host.h_name = bp;
	bp += n;
	buflen -= n;
	continue;
	}
	if (qtype == T_PTR && type == T_CNAME) {
	n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
	if (n < 0 \|\| !res_dnok(tbuf)) {
	had_error++;
	continue;
	}
	cp += n;
	if (cp != erdata) {
	h_errno = NO_RECOVERY;
	return (NULL);
	}
	/* Get canonical name. */
	n = (int)strlen(tbuf) + 1; /* for the \0 */
	if (n > buflen \|\| n >= MAXHOSTNAMELEN) {
	had_error++;
	continue;
	}
	strcpy(bp, tbuf);
	tname = bp;
	bp += n;
	buflen -= n;
	continue;
	}
	if (type != qtype) {
	#ifdef _ORG_FREEBSD_
	syslog(LOG_NOTICE\|LOG_AUTH,
	"gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
	qname, p_class(C_IN), p_type(qtype),
	p_type(type));
	#endif
	cp += n;
	continue; /* XXX - had_error++ ? */
	}
	switch (type) {
	case T_PTR:
	if (strcasecmp(tname, bp) != 0) {
	#ifdef _ORG_FREEBSD_
	syslog(LOG_NOTICE\|LOG_AUTH,
	AskedForGot, qname, bp);
	#endif
	cp += n;
	continue; /* XXX - had_error++ ? */
	}
	n = dn_expand(answer->buf, eom, cp, bp, buflen);
	if ((n < 0) \|\| !res_hnok(bp)) {
	had_error++;
	break;
	}
	#if MULTI_PTRS_ARE_ALIASES
	cp += n;
	if (cp != erdata) {
	h_errno = NO_RECOVERY;
	return (NULL);
	}
	if (!haveanswer)
	host.h_name = bp;
	else if (ap < &host_aliases[MAXALIASES-1])
	*ap++ = bp;
	else
	n = -1;
	if (n != -1) {
	n = (int)strlen(bp) + 1; /* for the \0 */
	if (n >= MAXHOSTNAMELEN) {
	had_error++;
	break;
	}
	bp += n;
	buflen -= n;
	}
	break;
	#else
	host.h_name = bp;
	if (_res.options & RES_USE_INET6) {
	n = strlen(bp) + 1; /* for the \0 */
	if (n >= MAXHOSTNAMELEN) {
	had_error++;
	break;
	}
	bp += n;
	buflen -= n;
	_map_v4v6_hostent(&host, &bp, &buflen);
	}
	h_errno = NETDB_SUCCESS;
	return (&host);
	#endif
	case T_A:
	case T_AAAA:
	if (strcasecmp(host.h_name, bp) != 0) {
	#ifdef _ORG_FREEBSD_
	syslog(LOG_NOTICE\|LOG_AUTH,
	AskedForGot, host.h_name, bp);
	#endif
	cp += n;
	continue; /* XXX - had_error++ ? */
	}
	if (n != host.h_length) {
	cp += n;
	continue;
	}
	if (!haveanswer) {
	register int nn;

	host.h_name = bp;
	nn = (int)strlen(bp) + 1; /* for the \0 */
	bp += nn;
	buflen -= nn;
	}

	bp += sizeof(align) - ((size_t)bp % sizeof(align));

	if (bp + n >= &hostbuf[sizeof hostbuf]) {
	dprintf("size (%d) too big\n", n);
	had_error++;
	continue;
	}
	if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
	if (!toobig++)
	dprintf("Too many addresses (%d)\n",
	MAXADDRS);
	cp += n;
	continue;
	}
	*hap++ = bp;
	bcopy(cp, bp, n);
	bp += n;
	buflen -= n;
	cp += n;
	if (cp != erdata) {
	h_errno = NO_RECOVERY;
	return (NULL);
	}
	break;
	default:
	dprintf("Impossible condition (type=%d)\n", type);
	h_errno = NO_RECOVERY;
	return (NULL);
	/* BIND has abort() here, too risky on bad data */
	}
	if (!had_error)
	haveanswer++;
	}
	if (haveanswer) {
	*ap = NULL;
	*hap = NULL;
	# if defined(RESOLVSORT)
	/*
	* Note: we sort even if host can take only one address
	* in its return structures - should give it the "best"
	* address in that case, not some random one
	*/
	if (_res.nsort && haveanswer > 1 && qtype == T_A)
	addrsort(h_addr_ptrs, haveanswer);
	# endif /RESOLVSORT/
	if (!host.h_name) {
	n = (int)strlen(qname) + 1; /* for the \0 */
	if (n > buflen \|\| n >= MAXHOSTNAMELEN)
	goto no_recovery;
	strcpy(bp, qname);
	host.h_name = bp;
	bp += n;
	buflen -= n;
	}
	if (_res.options & RES_USE_INET6)
	_map_v4v6_hostent(&host, &bp, &buflen);
	h_errno = NETDB_SUCCESS;
	return (&host);
	}
	no_recovery:
	h_errno = NO_RECOVERY;
	return (NULL);
	}

	struct hostent *
	__dns_getanswer(const char answer, int anslen, const char qname, int qtype)
	{
	switch(qtype) {
	case T_AAAA:
	host.h_addrtype = AF_INET6;
	host.h_length = IN6ADDRSZ;
	break;
	case T_A:
	default:
	host.h_addrtype = AF_INET;
	host.h_length = INADDRSZ;
	break;
	}

	return(gethostanswer((const querybuf *)answer, anslen, qname, qtype));
	}

	struct hostent *
	_gethostbydnsname(const char *name, int af)
	{
	querybuf buf;
	register const char *cp;
	char *bp;
	int n, size, type, len;

	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
	h_errno = NETDB_INTERNAL;
	return (NULL);
	}

	switch (af) {
	case AF_INET:
	size = INADDRSZ;
	type = T_A;
	break;
	case AF_INET6:
	size = IN6ADDRSZ;
	type = T_AAAA;
	break;
	default:
	h_errno = NETDB_INTERNAL;
	errno = EAFNOSUPPORT;
	return (NULL);
	}

	host.h_addrtype = af;
	host.h_length = size;

	/*
	* if there aren't any dots, it could be a user-level alias.
	* this is also done in res_query() since we are not the only
	* function that looks up host names.
	*/
	if (!strchr(name, '.') && ( NULL != (cp = __hostalias(name))))
	name = cp;

	/*
	* disallow names consisting only of digits/dots, unless
	* they end in a dot.
	*/
	if (isdigit(name[0]))
	for (cp = name;; ++cp) {
	if (!*cp) {
	if (*--cp == '.')
	break;
	/*
	* All-numeric, no dot at the end.
	* Fake up a hostent as if we'd actually
	* done a lookup.
	*/
	if (inet_pton(af, name, host_addr) <= 0) {
	h_errno = HOST_NOT_FOUND;
	return (NULL);
	}
	strncpy(hostbuf, name, MAXDNAME);
	hostbuf[MAXDNAME] = '\0';
	bp = hostbuf + MAXDNAME;
	len = sizeof hostbuf - MAXDNAME;
	host.h_name = hostbuf;
	host.h_aliases = host_aliases;
	host_aliases[0] = NULL;
	h_addr_ptrs[0] = (char *)host_addr;
	h_addr_ptrs[1] = NULL;
	host.h_addr_list = h_addr_ptrs;
	if (_res.options & RES_USE_INET6)
	_map_v4v6_hostent(&host, &bp, &len);
	h_errno = NETDB_SUCCESS;
	return (&host);
	}
	if (!isdigit(cp) && cp != '.')
	break;
	}
	if ((isxdigit(name[0]) && strchr(name, ':') != NULL) \|\|
	name[0] == ':')
	for (cp = name;; ++cp) {
	if (!*cp) {
	if (*--cp == '.')
	break;
	/*
	* All-IPv6-legal, no dot at the end.
	* Fake up a hostent as if we'd actually
	* done a lookup.
	*/
	if (inet_pton(af, name, host_addr) <= 0) {
	h_errno = HOST_NOT_FOUND;
	return (NULL);
	}
	strncpy(hostbuf, name, MAXDNAME);
	hostbuf[MAXDNAME] = '\0';
	bp = hostbuf + MAXDNAME;
	len = sizeof hostbuf - MAXDNAME;
	host.h_name = hostbuf;
	host.h_aliases = host_aliases;
	host_aliases[0] = NULL;
	h_addr_ptrs[0] = (char *)host_addr;
	h_addr_ptrs[1] = NULL;
	host.h_addr_list = h_addr_ptrs;
	h_errno = NETDB_SUCCESS;
	return (&host);
	}
	if (!isxdigit(cp) && cp != ':' && *cp != '.')
	break;
	}

	if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf))) < 0) {
	dprintf("res_search failed (%d)\n", n);
	return (NULL);
	}
	return (gethostanswer(&buf, n, name, type));
	}

	struct hostent *
	_gethostbydnsaddr(const char *addr, int len, int af)
	{
	const u_char uaddr = (const u_char )addr;
	static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
	static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
	int n, size;
	querybuf buf;
	register struct hostent *hp;
	char qbuf[MAXDNAME+1], *qp;
	#ifdef SUNSECURITY
	register struct hostent *rhp;
	char **haddr;
	u_long old_options;
	char hname2[MAXDNAME+1];
	#endif /SUNSECURITY/

	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
	h_errno = NETDB_INTERNAL;
	return (NULL);
	}
	if (af == AF_INET6 && len == IN6ADDRSZ &&
	(!bcmp(uaddr, mapped, sizeof mapped) \|\|
	!bcmp(uaddr, tunnelled, sizeof tunnelled))) {
	/* Unmap. */
	addr += sizeof mapped;
	uaddr += sizeof mapped;
	af = AF_INET;
	len = INADDRSZ;
	}
	switch (af) {
	case AF_INET:
	size = INADDRSZ;
	break;
	case AF_INET6:
	size = IN6ADDRSZ;
	break;
	default:
	errno = EAFNOSUPPORT;
	h_errno = NETDB_INTERNAL;
	return (NULL);
	}
	if (size != len) {
	errno = EINVAL;
	h_errno = NETDB_INTERNAL;
	return (NULL);
	}
	switch (af) {
	case AF_INET:
	(void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
	(uaddr[3] & 0xff),
	(uaddr[2] & 0xff),
	(uaddr[1] & 0xff),
	(uaddr[0] & 0xff));
	break;
	case AF_INET6:
	qp = qbuf;
	for (n = IN6ADDRSZ - 1; n >= 0; n--) {
	qp += SPRINTF((qp, "%x.%x.",
	uaddr[n] & 0xf,
	(uaddr[n] >> 4) & 0xf));
	}
	strcpy(qp, "ip6.int");
	break;
	default:
	abort();
	}
	n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
	if (n < 0) {
	dprintf("res_query failed (%d)\n", n);
	return (NULL);
	}
	if ( NULL == (hp = gethostanswer(&buf, n, qbuf, T_PTR)))
	return (NULL); /* h_errno was set by gethostanswer() */
	#ifdef SUNSECURITY
	if (af == AF_INET) {
	/*
	* turn off search as the name should be absolute,
	* 'localhost' should be matched by defnames
	*/
	strncpy(hname2, hp->h_name, MAXDNAME);
	hname2[MAXDNAME] = '\0';
	old_options = _res.options;
	_res.options &= ~RES_DNSRCH;
	_res.options \|= RES_DEFNAMES;
	if (!(rhp = gethostbyname(hname2))) {
	#ifdef _ORG_FREEBSD_
	syslog(LOG_NOTICE\|LOG_AUTH,
	"gethostbyaddr: No A record for %s (verifying [%s])",
	hname2, inet_ntoa(((struct in_addr )addr)));
	#endif
	_res.options = old_options;
	h_errno = HOST_NOT_FOUND;
	return (NULL);
	}
	_res.options = old_options;
	for (haddr = rhp->h_addr_list; *haddr; haddr++)
	if (!memcmp(*haddr, addr, INADDRSZ))
	break;
	if (!*haddr) {
	#ifdef _ORG_FREEBSD_
	syslog(LOG_NOTICE\|LOG_AUTH,
	"gethostbyaddr: A record of %s != PTR record [%s]",
	hname2, inet_ntoa(((struct in_addr )addr)));
	#endif
	h_errno = HOST_NOT_FOUND;
	return (NULL);
	}
	}
	#endif /SUNSECURITY/
	hp->h_addrtype = af;
	hp->h_length = len;
	bcopy(addr, host_addr, len);
	h_addr_ptrs[0] = (char *)host_addr;
	h_addr_ptrs[1] = NULL;
	if (af == AF_INET && (_res.options & RES_USE_INET6)) {
	_map_v4v6_address((char)host_addr, (char)host_addr);
	hp->h_addrtype = AF_INET6;
	hp->h_length = IN6ADDRSZ;
	}
	h_errno = NETDB_SUCCESS;
	return (hp);
	}

	#ifdef RESOLVSORT
	static void
	addrsort(char **ap, int num)
	{
	short i, j;
	char **p;
	short aval[MAXADDRS];
	short needsort = 0;

	p = ap;
	for (i = 0; i < num; i++, p++) {
	for (j = 0 ; (unsigned)j < _res.nsort; j++)
	if (_res.sort_list[j].addr.s_addr ==
	(((struct in_addr )(p))->s_addr & _res.sort_list[j].mask))
	break;
	aval[i] = j;
	if (needsort == 0 && i > 0 && j < aval[i-1])
	needsort = i;
	}
	if (!needsort)
	return;

	while (needsort < num) {
	for (j = needsort - 1; j >= 0; j--) {
	if (aval[j] > aval[j+1]) {
	char *hp;

	i = aval[j];
	aval[j] = aval[j+1];
	aval[j+1] = i;

	hp = ap[j];
	ap[j] = ap[j+1];
	ap[j+1] = hp;

	} else
	break;
	}
	needsort++;
	}
	}
	#endif
	void
	_sethostdnsent(int stayopen)
	{
	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
	return;
	if (stayopen)
	_res.options \|= RES_STAYOPEN \| RES_USEVC;
	}

	void
	_endhostdnsent()
	{
	_res.options &= ~(RES_STAYOPEN \| RES_USEVC);
	res_close();
	}