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distrib > Mandriva > 2010.0 > i586 > media > contrib-release > by-pkgid > ccd6d20295ff28f0d90115b0394355f1 > files > 142

libdnssec-tools-devel-1.5-2mdv2010.0.i586.rpm

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Netscape Portable Runtime (NSPR).
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998-2000
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "primpl.h"

#include <string.h>

#ifdef MOZ_DNSSEC
#include <validator/validator.h>
#endif

/*
 * On Unix, the error code for gethostbyname() and gethostbyaddr()
 * is returned in the global variable h_errno, instead of the usual
 * errno.
 */
#if defined(XP_UNIX)
#if defined(_PR_NEED_H_ERRNO)
extern int h_errno;
#endif
#define _MD_GETHOST_ERRNO() h_errno
#else
#define _MD_GETHOST_ERRNO() _MD_ERRNO()
#endif

/*
 * The meaning of the macros related to gethostbyname, gethostbyaddr,
 * and gethostbyname2 is defined below.
 * - _PR_HAVE_THREADSAFE_GETHOST: the gethostbyXXX functions return
 *   the result in thread specific storage.  For example, AIX, HP-UX,
 *   and OSF1.
 * -  _PR_HAVE_GETHOST_R: have the gethostbyXXX_r functions. See next
 *   two macros.
 * - _PR_HAVE_GETHOST_R_INT: the gethostbyXXX_r functions return an
 *   int.  For example, Linux glibc.
 * - _PR_HAVE_GETHOST_R_POINTER: the gethostbyXXX_r functions return
 *   a struct hostent* pointer.  For example, Solaris and IRIX.
 */
#if (defined(_PR_NO_PREEMPT) || defined(_PR_HAVE_GETHOST_R) \
     || defined(_PR_HAVE_THREADSAFE_GETHOST))
#define _PR_NO_DNS_LOCK
#endif

#if defined(_PR_NO_DNS_LOCK)
#define LOCK_DNS()
#define UNLOCK_DNS()
#else
PRLock *_pr_dnsLock = NULL;
#define LOCK_DNS() PR_Lock(_pr_dnsLock)
#define UNLOCK_DNS() PR_Unlock(_pr_dnsLock)
#endif  /* defined(_PR_NO_DNS_LOCK) */

/*
 * Some platforms have the reentrant getprotobyname_r() and
 * getprotobynumber_r().  However, they come in two flavors.
 * Some return a pointer to struct protoent, others return
 * an int.
 */
#if defined(XP_BEOS) && defined(BONE_VERSION)
#include <arpa/inet.h>  /* pick up define for inet_addr */
#include <sys/socket.h>
#define _PR_HAVE_GETPROTO_R
#define _PR_HAVE_GETPROTO_R_POINTER
#endif

#if defined(SOLARIS) || (defined(BSDI) && defined(_REENTRANT)) \
	|| (defined(LINUX) && defined(_REENTRANT) \
        && !(defined(__GLIBC__) && __GLIBC__ >= 2))
#define _PR_HAVE_GETPROTO_R
#define _PR_HAVE_GETPROTO_R_POINTER
#endif

#if defined(OSF1) \
        || defined(AIX4_3_PLUS) || (defined(AIX) && defined(_THREAD_SAFE)) \
	|| (defined(HPUX10_10) && defined(_REENTRANT)) \
        || (defined(HPUX10_20) && defined(_REENTRANT))
#define _PR_HAVE_GETPROTO_R
#define _PR_HAVE_GETPROTO_R_INT
#endif

#if __FreeBSD_version >= 602000
#define _PR_HAVE_GETPROTO_R
#define _PR_HAVE_5_ARG_GETPROTO_R
#endif

#if (defined(LINUX) && defined(__GLIBC__) && __GLIBC__ >= 2)
#define _PR_HAVE_GETPROTO_R
#define _PR_HAVE_5_ARG_GETPROTO_R
#endif

#if !defined(_PR_HAVE_GETPROTO_R)
PRLock* _getproto_lock = NULL;
#endif

#if defined(_PR_INET6_PROBE)
PR_EXTERN(PRBool) _pr_ipv6_is_present;
#endif

#define _PR_IN6_IS_ADDR_UNSPECIFIED(a)				\
				(((a)->pr_s6_addr32[0] == 0) &&	\
				((a)->pr_s6_addr32[1] == 0) &&		\
				((a)->pr_s6_addr32[2] == 0) &&		\
				((a)->pr_s6_addr32[3] == 0))
 
#define _PR_IN6_IS_ADDR_LOOPBACK(a)					\
               (((a)->pr_s6_addr32[0] == 0)	&&	\
               ((a)->pr_s6_addr32[1] == 0)		&&	\
               ((a)->pr_s6_addr32[2] == 0)		&&	\
               ((a)->pr_s6_addr[12] == 0)		&&	\
               ((a)->pr_s6_addr[13] == 0)		&&	\
               ((a)->pr_s6_addr[14] == 0)		&&	\
               ((a)->pr_s6_addr[15] == 0x1U))
 
const PRIPv6Addr _pr_in6addr_any =	{{{ 0, 0, 0, 0,
										0, 0, 0, 0,
										0, 0, 0, 0,
										0, 0, 0, 0 }}};

const PRIPv6Addr _pr_in6addr_loopback = {{{ 0, 0, 0, 0,
											0, 0, 0, 0,
											0, 0, 0, 0,
											0, 0, 0, 0x1U }}};
/*
 * The values at bytes 10 and 11 are compared using pointers to
 * 8-bit fields, and not 32-bit fields, to make the comparison work on
 * both big-endian and little-endian systems
 */

#define _PR_IN6_IS_ADDR_V4MAPPED(a)			\
		(((a)->pr_s6_addr32[0] == 0) 	&&	\
		((a)->pr_s6_addr32[1] == 0)	&&	\
		((a)->pr_s6_addr[8] == 0)		&&	\
		((a)->pr_s6_addr[9] == 0)		&&	\
		((a)->pr_s6_addr[10] == 0xff)	&&	\
		((a)->pr_s6_addr[11] == 0xff))

#define _PR_IN6_IS_ADDR_V4COMPAT(a)			\
		(((a)->pr_s6_addr32[0] == 0) &&	\
		((a)->pr_s6_addr32[1] == 0) &&		\
		((a)->pr_s6_addr32[2] == 0))

#define _PR_IN6_V4MAPPED_TO_IPADDR(a) ((a)->pr_s6_addr32[3])

#if defined(_PR_INET6) && defined(_PR_HAVE_GETHOSTBYNAME2)

/*
 * The _pr_QueryNetIfs() function finds out if the system has
 * IPv4 or IPv6 source addresses configured and sets _pr_have_inet_if
 * and _pr_have_inet6_if accordingly.
 *
 * We have an implementation using SIOCGIFCONF ioctl and a
 * default implementation that simply sets _pr_have_inet_if
 * and _pr_have_inet6_if to true.  A better implementation
 * would be to use the routing sockets (see Chapter 17 of
 * W. Richard Stevens' Unix Network Programming, Vol. 1, 2nd. Ed.)
 */

static PRLock *_pr_query_ifs_lock = NULL;
static PRBool _pr_have_inet_if = PR_FALSE;
static PRBool _pr_have_inet6_if = PR_FALSE;

#undef DEBUG_QUERY_IFS

#if defined(AIX) \
    || (defined(DARWIN) && (!defined(HAVE_GETIFADDRS) \
        || (defined(XP_MACOSX) && (!defined(MAC_OS_X_VERSION_10_2) || \
        MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_2))))

/*
 * Use SIOCGIFCONF ioctl on platforms that don't have routing
 * sockets.  Warning: whether SIOCGIFCONF ioctl returns AF_INET6
 * network interfaces is not portable.
 *
 * The _pr_QueryNetIfs() function is derived from the code in
 * src/lib/libc/net/getifaddrs.c in BSD Unix and the code in
 * Section 16.6 of W. Richard Stevens' Unix Network Programming,
 * Vol. 1, 2nd. Ed.
 */

#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>

#ifdef DEBUG_QUERY_IFS
static void
_pr_PrintIfreq(struct ifreq *ifr)
{
    PRNetAddr addr;
    struct sockaddr *sa;
    const char* family;
    char addrstr[64];

    sa = &ifr->ifr_addr;
    if (sa->sa_family == AF_INET) {
        struct sockaddr_in *sin = (struct sockaddr_in *)sa;
        family = "inet";
        memcpy(&addr.inet.ip, &sin->sin_addr, sizeof(sin->sin_addr));
    } else if (sa->sa_family == AF_INET6) {
        struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
        family = "inet6";
        memcpy(&addr.ipv6.ip, &sin6->sin6_addr, sizeof(sin6->sin6_addr));
    } else {
        return;  /* skip if not AF_INET or AF_INET6 */
    }
    addr.raw.family = sa->sa_family;
    PR_NetAddrToString(&addr, addrstr, sizeof(addrstr));
    printf("%s: %s %s\n", ifr->ifr_name, family, addrstr);
}
#endif

static void
_pr_QueryNetIfs(void)
{
    int sock;
    int rv;
    struct ifconf ifc;
    struct ifreq *ifr;
    struct ifreq *lifr;
    PRUint32 len, lastlen;
    char *buf;

    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        return;
    }

    /* Issue SIOCGIFCONF request in a loop. */
    lastlen = 0;
    len = 100 * sizeof(struct ifreq);  /* initial buffer size guess */
    for (;;) {
        buf = (char *)PR_Malloc(len);
        if (NULL == buf) {
            close(sock);
            return;
        }
        ifc.ifc_buf = buf;
        ifc.ifc_len = len;
        rv = ioctl(sock, SIOCGIFCONF, &ifc);
        if (rv < 0) {
            if (errno != EINVAL || lastlen != 0) {
                close(sock);
                PR_Free(buf);
                return;
            }
        } else {
            if (ifc.ifc_len == lastlen)
                break;  /* success, len has not changed */
            lastlen = ifc.ifc_len;
        }
        len += 10 * sizeof(struct ifreq);  /* increment */
        PR_Free(buf);
    }
    close(sock);

    ifr = ifc.ifc_req;
    lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];

    while (ifr < lifr) {
        struct sockaddr *sa;
        int sa_len;

#ifdef DEBUG_QUERY_IFS
        _pr_PrintIfreq(ifr);
#endif
        sa = &ifr->ifr_addr;
        if (sa->sa_family == AF_INET) {
            struct sockaddr_in *sin = (struct sockaddr_in *) sa;
            if (sin->sin_addr.s_addr != htonl(INADDR_LOOPBACK)) {
                _pr_have_inet_if = PR_TRUE;
            } 
        } else if (sa->sa_family == AF_INET6) {
            struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) sa;
            if (!IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)
                    && !IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
                _pr_have_inet6_if = PR_TRUE;
            } 
        }

#ifdef _PR_HAVE_SOCKADDR_LEN
        sa_len = PR_MAX(sa->sa_len, sizeof(struct sockaddr));
#else
        switch (sa->sa_family) {
#ifdef AF_LINK
        case AF_LINK:
            sa_len = sizeof(struct sockaddr_dl);
            break;
#endif
        case AF_INET6:
            sa_len = sizeof(struct sockaddr_in6);
            break;
        default:
            sa_len = sizeof(struct sockaddr);
            break;
        }
#endif
        ifr = (struct ifreq *)(((char *)sa) + sa_len);
    }
    PR_Free(buf);
}

#elif (defined(DARWIN) && defined(HAVE_GETIFADDRS)) || defined(FREEBSD) \
    || defined(NETBSD) || defined(OPENBSD)

/*
 * Use the BSD getifaddrs function.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <ifaddrs.h>
#include <netinet/in.h>

#ifdef DEBUG_QUERY_IFS
static void
_pr_PrintIfaddrs(struct ifaddrs *ifa)
{
    struct sockaddr *sa;
    const char* family;
    void *addrp;
    char addrstr[64];

    sa = ifa->ifa_addr;
    if (sa->sa_family == AF_INET) {
        struct sockaddr_in *sin = (struct sockaddr_in *)sa;
        family = "inet";
        addrp = &sin->sin_addr;
    } else if (sa->sa_family == AF_INET6) {
        struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
        family = "inet6";
        addrp = &sin6->sin6_addr;
    } else {
        return;  /* skip if not AF_INET or AF_INET6 */
    }
    inet_ntop(sa->sa_family, addrp, addrstr, sizeof(addrstr));
    printf("%s: %s %s\n", ifa->ifa_name, family, addrstr);
}
#endif

static void
_pr_QueryNetIfs(void)
{
    struct ifaddrs *ifp;
    struct ifaddrs *ifa;

    if (getifaddrs(&ifp) == -1) {
        return;
    }
    for (ifa = ifp; ifa; ifa = ifa->ifa_next) {
        struct sockaddr *sa;

#ifdef DEBUG_QUERY_IFS
        _pr_PrintIfaddrs(ifa);
#endif
        sa = ifa->ifa_addr;
        if (sa->sa_family == AF_INET) {
            struct sockaddr_in *sin = (struct sockaddr_in *) sa;
            if (sin->sin_addr.s_addr != htonl(INADDR_LOOPBACK)) {
                _pr_have_inet_if = 1;
            } 
        } else if (sa->sa_family == AF_INET6) {
            struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) sa;
            if (!IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)
                    && !IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
                _pr_have_inet6_if = 1;
            } 
        }
    } 
    freeifaddrs(ifp);
}

#else  /* default */

/*
 * Emulate the code in NSPR 4.2 or older.  PR_GetIPNodeByName behaves
 * as if the system had both IPv4 and IPv6 source addresses configured.
 */
static void
_pr_QueryNetIfs(void)
{
    _pr_have_inet_if = PR_TRUE;
    _pr_have_inet6_if = PR_TRUE;
}

#endif

#endif  /* _PR_INET6 && _PR_HAVE_GETHOSTBYNAME2 */

void _PR_InitNet(void)
{
#if defined(XP_UNIX)
#ifdef HAVE_NETCONFIG
	/*
	 * This one-liner prevents the endless re-open's and re-read's of
	 * /etc/netconfig on EACH and EVERY call to accept(), connect(), etc.
	 */
	 (void)setnetconfig();
#endif
#endif
#if !defined(_PR_NO_DNS_LOCK)
	_pr_dnsLock = PR_NewLock();
#endif
#if !defined(_PR_HAVE_GETPROTO_R)
	_getproto_lock = PR_NewLock();
#endif
#if defined(_PR_INET6) && defined(_PR_HAVE_GETHOSTBYNAME2)
	_pr_query_ifs_lock = PR_NewLock();
#endif
}

void _PR_CleanupNet(void)
{
#if !defined(_PR_NO_DNS_LOCK)
    if (_pr_dnsLock) {
        PR_DestroyLock(_pr_dnsLock);
        _pr_dnsLock = NULL;
    }
#endif
#if !defined(_PR_HAVE_GETPROTO_R)
    if (_getproto_lock) {
        PR_DestroyLock(_getproto_lock);
        _getproto_lock = NULL;
    }
#endif
#if defined(_PR_INET6) && defined(_PR_HAVE_GETHOSTBYNAME2)
    if (_pr_query_ifs_lock) {
        PR_DestroyLock(_pr_query_ifs_lock);
        _pr_query_ifs_lock = NULL;
    }
#endif
}

/*
** Allocate space from the buffer, aligning it to "align" before doing
** the allocation. "align" must be a power of 2.
*/
static char *Alloc(PRIntn amount, char **bufp, PRIntn *buflenp, PRIntn align)
{
	char *buf = *bufp;
	PRIntn buflen = *buflenp;

	if (align && ((long)buf & (align - 1))) {
		PRIntn skip = align - ((ptrdiff_t)buf & (align - 1));
		if (buflen < skip) {
			return 0;
		}
		buf += skip;
		buflen -= skip;
	}
	if (buflen < amount) {
		return 0;
	}
	*bufp = buf + amount;
	*buflenp = buflen - amount;
	return buf;
}

typedef enum _PRIPAddrConversion {
    _PRIPAddrNoConversion,
    _PRIPAddrIPv4Mapped,
    _PRIPAddrIPv4Compat
} _PRIPAddrConversion;

/*
** Convert an IPv4 address (v4) to an IPv4-mapped IPv6 address (v6).
*/
static void MakeIPv4MappedAddr(const char *v4, char *v6)
{
    memset(v6, 0, 10);
    memset(v6 + 10, 0xff, 2);
    memcpy(v6 + 12, v4, 4);
}

/*
** Convert an IPv4 address (v4) to an IPv4-compatible IPv6 address (v6).
*/
static void MakeIPv4CompatAddr(const char *v4, char *v6)
{
    memset(v6, 0, 12);
    memcpy(v6 + 12, v4, 4);
}

/*
** Copy a hostent, and all of the memory that it refers to into
** (hopefully) stacked buffers.
*/
static PRStatus CopyHostent(
    struct hostent *from,
    char **buf,
    PRIntn *bufsize,
    _PRIPAddrConversion conversion,
    PRHostEnt *to)
{
	PRIntn len, na;
	char **ap;

	if (conversion != _PRIPAddrNoConversion
			&& from->h_addrtype == AF_INET) {
		PR_ASSERT(from->h_length == 4);
		to->h_addrtype = PR_AF_INET6;
		to->h_length = 16;
	} else {
#if defined(_PR_INET6) || defined(_PR_INET6_PROBE)
		if (AF_INET6 == from->h_addrtype)
			to->h_addrtype = PR_AF_INET6;
		else
#endif
			to->h_addrtype = from->h_addrtype;
		to->h_length = from->h_length;
	}

	/* Copy the official name */
	if (!from->h_name) return PR_FAILURE;
	len = strlen(from->h_name) + 1;
	to->h_name = Alloc(len, buf, bufsize, 0);
	if (!to->h_name) return PR_FAILURE;
	memcpy(to->h_name, from->h_name, len);

	/* Count the aliases, then allocate storage for the pointers */
	if (!from->h_aliases) {
		na = 1;
	} else {
		for (na = 1, ap = from->h_aliases; *ap != 0; na++, ap++){;} /* nothing to execute */
	}
	to->h_aliases = (char**)Alloc(
	    na * sizeof(char*), buf, bufsize, sizeof(char**));
	if (!to->h_aliases) return PR_FAILURE;

	/* Copy the aliases, one at a time */
	if (!from->h_aliases) {
		to->h_aliases[0] = 0;
	} else {
		for (na = 0, ap = from->h_aliases; *ap != 0; na++, ap++) {
			len = strlen(*ap) + 1;
			to->h_aliases[na] = Alloc(len, buf, bufsize, 0);
			if (!to->h_aliases[na]) return PR_FAILURE;
			memcpy(to->h_aliases[na], *ap, len);
		}
		to->h_aliases[na] = 0;
	}

	/* Count the addresses, then allocate storage for the pointers */
	for (na = 1, ap = from->h_addr_list; *ap != 0; na++, ap++){;} /* nothing to execute */
	to->h_addr_list = (char**)Alloc(
	    na * sizeof(char*), buf, bufsize, sizeof(char**));
	if (!to->h_addr_list) return PR_FAILURE;

	/* Copy the addresses, one at a time */
	for (na = 0, ap = from->h_addr_list; *ap != 0; na++, ap++) {
		to->h_addr_list[na] = Alloc(to->h_length, buf, bufsize, 0);
		if (!to->h_addr_list[na]) return PR_FAILURE;
		if (conversion != _PRIPAddrNoConversion
				&& from->h_addrtype == AF_INET) {
			if (conversion == _PRIPAddrIPv4Mapped) {
				MakeIPv4MappedAddr(*ap, to->h_addr_list[na]);
			} else {
				PR_ASSERT(conversion == _PRIPAddrIPv4Compat);
				MakeIPv4CompatAddr(*ap, to->h_addr_list[na]);
			}
		} else {
			memcpy(to->h_addr_list[na], *ap, to->h_length);
		}
	}
	to->h_addr_list[na] = 0;
	return PR_SUCCESS;
}

#if !defined(_PR_HAVE_GETPROTO_R)
/*
** Copy a protoent, and all of the memory that it refers to into
** (hopefully) stacked buffers.
*/
static PRStatus CopyProtoent(
    struct protoent *from, char *buf, PRIntn bufsize, PRProtoEnt *to)
{
	PRIntn len, na;
	char **ap;

	/* Do the easy stuff */
	to->p_num = from->p_proto;

	/* Copy the official name */
	if (!from->p_name) return PR_FAILURE;
	len = strlen(from->p_name) + 1;
	to->p_name = Alloc(len, &buf, &bufsize, 0);
	if (!to->p_name) return PR_FAILURE;
	memcpy(to->p_name, from->p_name, len);

	/* Count the aliases, then allocate storage for the pointers */
	for (na = 1, ap = from->p_aliases; *ap != 0; na++, ap++){;} /* nothing to execute */
	to->p_aliases = (char**)Alloc(
	    na * sizeof(char*), &buf, &bufsize, sizeof(char**));
	if (!to->p_aliases) return PR_FAILURE;

	/* Copy the aliases, one at a time */
	for (na = 0, ap = from->p_aliases; *ap != 0; na++, ap++) {
		len = strlen(*ap) + 1;
		to->p_aliases[na] = Alloc(len, &buf, &bufsize, 0);
		if (!to->p_aliases[na]) return PR_FAILURE;
		memcpy(to->p_aliases[na], *ap, len);
	}
	to->p_aliases[na] = 0;

	return PR_SUCCESS;
}
#endif /* !defined(_PR_HAVE_GETPROTO_R) */

#define DNSSEC_FAILURE 0
#define DNSSEC_SUCCESS 1
/* START DNSSEC INTERNAL */
#define DODNSSECDEBUG
#ifdef DODNSSECDEBUG
#define DNSSECDEBUG(x) fprintf x;
#define DNSSECFUNBEGIN()                        \
  {                                             \
    fprintf(stderr, "vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv\n"); \
    fprintf(stderr, "BEGIN  %s:%d: \n  ", __FUNCTION__, __LINE__);       \
  }
#define DNSSECFUNDEBUG(x) { DNSSECFUNBEGIN(); DNSSECDEBUG(x); }
#define DNSSECFUNEXIT()   {                                             \
    fprintf(stderr, "EXIT   %s:%d:  \n", __FUNCTION__, __LINE__);          \
    fprintf(stderr, "^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n"); \
  }
#define DNSSECFUNRETURN(retval)    \
  {                                             \
    DNSSECDEBUG((stderr, "  returning: %x", (unsigned int) retval));    \
    if ((int) retval == DNSSEC_SUCCESS) {                                \
      DNSSECDEBUG((stderr, "  (success)"));                             \
    } else if ((int) retval == DNSSEC_SUCCESS || (int) retval == -1) {   \
      DNSSECDEBUG((stderr, "  (FAIL)"));                                \
    }                                                                   \
    DNSSECDEBUG((stderr, "\n"));						    \
    DNSSECFUNEXIT();                                                    \
    return retval;                                                      \
  }
#else
#define DNSSECDEBUG(x) 
#define DNSSECFUNDEBUG(x) 
#define DNSSECFUNEXIT()
#define DNSSECFUNRETURN(retval) return retval;
#endif
/* END DNSSEC INTERNAL */


/* 0 = enforce system policy, 1 = ignore, 2 = always secure */
int global_policy = 0;
#define DNSSEC_POLICY_ENFORCE_SYS_POLICY 0
#define DNSSEC_POLICY_IGNORE              1
#define DNSSEC_POLICY_ALWAYS_SECURE       2
void
PR_set_dnssec_validate_policy(int policy)
{
  DNSSECFUNDEBUG((stderr, "DNSSEC Setting policy: %d\n", policy));
  global_policy = policy;
}


#ifdef MOZ_DNSSEC
/* XXX: include drop or configurize */
#include <stdio.h>
#include <netdb.h>

/* prototypes */
int dnssec_check_policy(int dnssec_status, int policytype);
/**
 * dnssec_validate(HOSTNAME)
 *
 * attempts to validate HOSTNAME using dnssec.  It will return one of:
 *
 * If global_policy = DNSSEC_POLICY_IGNORE
 *    - DNSSEC_SUCCESS: 
 *
 * If global_policy = DNSSEC_POLICY_ENFORCE_SYS_POLICY
 *    - DNSSEC_SUCCESS if verified
 *    - DNSSEC_FAILURE if not
 *
 * If global_policy = DNSSEC_POLICY_ENFORCE_SYS_POLICY
 *    - DNSSEC_SUCCESS if verified
 *    - DNSSEC_FAILURE if not
 */
/* XXX: pass in address type? */
int dnssec_validate (const char *domain_name) {
    int dnssec_status;
    struct hostent hentry, *hentryp;
    char buf[1024];
    size_t buflen = sizeof(buf);
    int h_errno;
    val_status_t val_status;

    DNSSECFUNDEBUG((stderr, "DNSSECvalidating: %s\n", domain_name));
    
    /* don't even bother validating when the policy doesn't call for it */
    if (global_policy == DNSSEC_POLICY_IGNORE) {
        DNSSECDEBUG((stderr, "  OK: policy is always allow\n"));
        DNSSECFUNRETURN(DNSSEC_SUCCESS);
    }

    /* explicitly catch localhost */
    if (strcmp(domain_name, "localhost") == 0) {
        DNSSECDEBUG((stderr, "  OK: 'localhost' is always allowed\n"));
        DNSSECFUNRETURN(DNSSEC_SUCCESS);
    }
    
    /* attempt a lookup */
    dnssec_status = val_gethostbyname_r(NULL, domain_name, &hentry,
                                        buf, buflen,&hentryp, &h_errno,
                                        &val_status);

    /* check the results, or assume indeterminate if we don't know why
       the above failed */
    DNSSECDEBUG((stderr, "  val_gethostbyname returned %d,val_st=%d,errno=%d,ptr=%x\n", dnssec_status, val_status, h_errno, (unsigned int) hentryp));
    if (!hentryp && val_status == VAL_DONT_KNOW)  // Should never happen?
        val_status = VAL_BOGUS;

    DNSSECDEBUG((stderr, "  val_gethostbyname's dnssec status was %d\n", dnssec_status));

    if (dnssec_check_policy(val_status, global_policy) == DNSSEC_SUCCESS)
        DNSSECFUNRETURN(DNSSEC_SUCCESS);

    DNSSECFUNRETURN(DNSSEC_FAILURE);
}

int
dnssec_check_policy(int val_status, int policytype) 
{
  DNSSECFUNDEBUG((stderr, "input: policy=%d, status=%d = %s\n", policytype, val_status, p_val_error(val_status)));

  /*
   * POLICY: if val_status == VAL_AC_UNSET then return SUCCESS (unknown host)
   *   (this is already an error)
   */
  if (val_status == VAL_AC_UNSET)
      DNSSECFUNRETURN(DNSSEC_SUCCESS);

  /*
   * POLICY: ignore errors
   */
  if (policytype == DNSSEC_POLICY_IGNORE)
      DNSSECFUNRETURN(DNSSEC_SUCCESS);

  /*
   * POLICY: require only when possible
   *   -- IE, trust the policy specified in dnssec-tools's dnsval.conf
   */
  if (policytype == DNSSEC_POLICY_ENFORCE_SYS_POLICY) {
    if (val_istrusted(val_status))
        DNSSECFUNRETURN(DNSSEC_SUCCESS);
    DNSSECFUNRETURN(DNSSEC_FAILURE);
  }
  
  /*
   * POLICY: always secure.
   *    -- IE, require all lookups to return only secure results
   */
  
  if (val_status == VAL_SUCCESS)
      DNSSECFUNRETURN(DNSSEC_SUCCESS);
  DNSSECFUNRETURN(DNSSEC_FAILURE);
}

struct hostent *
dnssec_gethostbyname(const char *name,
                     struct hostent *ret, char *buf, size_t buflen,
                     struct hostent **result, int *h_errnop)
{
  val_status_t val_status;
  int ret_stat;
  
  DNSSECFUNDEBUG((stderr, "input: name=%s\n", name));
  ret_stat = val_gethostbyname_r(NULL, name, ret, buf, buflen, result, h_errnop,
                                 &val_status);
  if (!ret_stat) {
    DNSSECDEBUG((stderr, "  ERROR: ret_stat=%d returned\n", ret_stat));
    DNSSECFUNRETURN(NULL);
  }
  
  if (dnssec_check_policy(val_status, global_policy) == DNSSEC_SUCCESS) {
    DNSSECDEBUG((stderr, "  policy = success\n"));
    DNSSECFUNRETURN(ret);
  }
  /* XXX: if ret exists (but policy says no), free it? */
  DNSSECDEBUG((stderr, "  failed to lookup host\n"));
  DNSSECFUNRETURN(NULL);
}

struct hostent *
dnssec_gethostbyname2(const char *name, int af,
                     struct hostent *ret, char *buf, size_t buflen,
                     struct hostent **result, int *h_errnop)
{
  val_status_t val_status;
  int ret_stat;
  
  DNSSECFUNDEBUG((stderr, "input: name=%s\n", name));
  ret_stat = val_gethostbyname2_r(NULL, name, af, 
                                  ret, buf, buflen, result, h_errnop,
                                  &val_status);
  if (!ret_stat) {
    DNSSECDEBUG((stderr, "  ERROR: ret_stat=%d returned\n", ret_stat));
    DNSSECFUNRETURN(NULL);
  }
  
  if (dnssec_check_policy(val_status, global_policy) == DNSSEC_SUCCESS) {
    DNSSECDEBUG((stderr, "  policy = success\n"));
    DNSSECFUNRETURN(ret);
  }
  /* XXX: if ret exists (but policy says no), free it? */
  DNSSECDEBUG((stderr, "  failed to lookup host\n"));
  DNSSECFUNRETURN(NULL);
}

#else  /* !MOZ_DNSSEC */

int dnssec_validate (const char *domain_name) {
  return DNSSEC_SUCCESS;
}

#endif /* !MOZ_DNSSEC */

/*
 * #################################################################
 * NOTE: tmphe, tmpbuf, bufsize, h, and h_err are local variables
 * or arguments of PR_GetHostByName, PR_GetIPNodeByName, and
 * PR_GetHostByAddr.  DO NOT CHANGE THE NAMES OF THESE LOCAL 
 * VARIABLES OR ARGUMENTS.
 * #################################################################
 */
#if defined(_PR_HAVE_GETHOST_R_INT)

#define GETHOSTBYNAME(name) \
    (gethostbyname_r(name, &tmphe, tmpbuf, bufsize, &h, &h_err), h)
#define GETHOSTBYNAME2(name, af) \
    (gethostbyname2_r(name, af, &tmphe, tmpbuf, bufsize, &h, &h_err), h)
#define GETHOSTBYADDR(addr, addrlen, af) \
    (gethostbyaddr_r(addr, addrlen, af, \
    &tmphe, tmpbuf, bufsize, &h, &h_err), h)

#elif defined(_PR_HAVE_GETHOST_R_POINTER)

#define GETHOSTBYNAME(name) \
    gethostbyname_r(name, &tmphe, tmpbuf, bufsize, &h_err)
#define GETHOSTBYNAME2(name, af) \
    gethostbyname2_r(name, af, &tmphe, tmpbuf, bufsize, &h_err)
#define GETHOSTBYADDR(addr, addrlen, af) \
    gethostbyaddr_r(addr, addrlen, af, &tmphe, tmpbuf, bufsize, &h_err)

#else

#define GETHOSTBYNAME(name) gethostbyname(name)
#define GETHOSTBYNAME2(name, af) gethostbyname2(name, af)
#define GETHOSTBYADDR(addr, addrlen, af) gethostbyaddr(addr, addrlen, af)

#endif  /* definition of GETHOSTBYXXX */

/* override functions if MOZ_DNSSEC is enabled */
#ifdef MOZ_DNSSEC

/* We do this in a special section to allow the GETHOSTBYADDR to be
   pulled above as normal.  Unfortunately, even though the DNSSEC APIs
   are thread safe, if GETHOSTBYADDR is not then we'll still perform
   safe locking because this code doesn't differentiate between calls
   at all.
*/
#undef GETHOSTBYNAME
#undef GETHOSTBYNAME2

#define GETHOSTBYNAME(name) \
    (dnssec_gethostbyname(name, &tmphe, tmpbuf, bufsize, &h, &h_err), h)
#define GETHOSTBYNAME2(name, af)                                           \
  (dnssec_gethostbyname2(name, af, &tmphe, tmpbuf, bufsize, &h, &h_err), h)

#endif /* MOZ_DNSSEC */

/* note: not DNSSEC specific, but only currently needed for DNSSEC */
/* converts a return value from one which may include other (newer)
   DNS error codes like those provided by DNSSEC validation to
   something which older code can still understand */
static void simplify_return_value(void)
{
  PRErrorCode errcode = PR_GetError();
  switch(errcode) {
    /* Pass the original codes */
  case PR_DNSSEC_VALIDATION_ERROR:
    PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, 0);
    break;
  case PR_DNSSEC_DNE_ERROR:
    PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, 0);
    break;
  default:
    /* everything else can pass on as before */
    break;
  }
}

PR_IMPLEMENT(PRStatus) PR_GetHostByNameExtended(
    const char *name, char *buf, PRIntn bufsize, PRHostEnt *hp)
{
	struct hostent *h;
	PRStatus rv = PR_FAILURE;
#if defined(_PR_HAVE_GETHOST_R)
    char localbuf[PR_NETDB_BUF_SIZE];
    char *tmpbuf;
    struct hostent tmphe;
    int h_err;
#endif

    if (!_pr_initialized) _PR_ImplicitInitialization();
    DNSSECFUNDEBUG((stderr, "input=%s\n", name));

#if defined(_PR_HAVE_GETHOST_R)
    tmpbuf = localbuf;
    if (bufsize > sizeof(localbuf))
    {
        tmpbuf = (char *)PR_Malloc(bufsize);
        if (NULL == tmpbuf)
        {
            PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
            DNSSECFUNRETURN(rv);
        }
    }
#endif

	LOCK_DNS();

#ifdef XP_OS2_VACPP
	h = GETHOSTBYNAME((char *)name);
#else
	h = GETHOSTBYNAME(name);
#endif

    /* XXX */
    DNSSECDEBUG((stderr, "DNSSECgethostbyname results: host=%s h_errno=%d\n", name, h_errno));
    if (NULL == h)
	{
        DNSSECDEBUG((stderr, "********** Status = LOOKUP_ERROR\n"));
	    PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_GETHOST_ERRNO());
	}
	else
	{
        DNSSECDEBUG((stderr, "********** Status = SUCCESS\n"));
		_PRIPAddrConversion conversion = _PRIPAddrNoConversion;
		rv = CopyHostent(h, &buf, &bufsize, conversion, hp);
		if (PR_SUCCESS != rv)
		    PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, 0);
	}
	UNLOCK_DNS();
#if defined(_PR_HAVE_GETHOST_R)
    if (tmpbuf != localbuf)
        PR_Free(tmpbuf);
#endif
    DNSSECFUNRETURN(rv);
}

PR_IMPLEMENT(PRStatus) PR_GetHostByName(
    const char *name, char *buf, PRIntn bufsize, PRHostEnt *hp)
{
    PRStatus ret;
    DNSSECFUNDEBUG((stderr, "input=%s\n", name));
    ret = PR_GetHostByNameExtended(name, buf, bufsize, hp);
    simplify_return_value();
    return ret;
}

#if !defined(_PR_INET6) && \
        defined(_PR_INET6_PROBE) && defined(_PR_HAVE_GETIPNODEBYNAME)
typedef struct hostent  * (*_pr_getipnodebyname_t)(const char *, int,
										int, int *);
typedef struct hostent  * (*_pr_getipnodebyaddr_t)(const void *, size_t,
													int, int *);
typedef void (*_pr_freehostent_t)(struct hostent *);
static void * _pr_getipnodebyname_fp;
static void * _pr_getipnodebyaddr_fp;
static void * _pr_freehostent_fp;

/*
 * Look up the addresses of getipnodebyname, getipnodebyaddr,
 * and freehostent.
 */
PRStatus
_pr_find_getipnodebyname(void)
{
    PRLibrary *lib;	
    PRStatus rv;
#if defined(VMS)
#define GETIPNODEBYNAME getenv("GETIPNODEBYNAME")
#define GETIPNODEBYADDR getenv("GETIPNODEBYADDR")
#define FREEHOSTENT     getenv("FREEHOSTENT")
#else
#define GETIPNODEBYNAME "getipnodebyname"
#define GETIPNODEBYADDR "getipnodebyaddr"
#define FREEHOSTENT     "freehostent"
#endif
    _pr_getipnodebyname_fp = PR_FindSymbolAndLibrary(GETIPNODEBYNAME, &lib);
    if (NULL != _pr_getipnodebyname_fp) {
        _pr_freehostent_fp = PR_FindSymbol(lib, FREEHOSTENT);
        if (NULL != _pr_freehostent_fp) {
            _pr_getipnodebyaddr_fp = PR_FindSymbol(lib, GETIPNODEBYADDR);
            if (NULL != _pr_getipnodebyaddr_fp)
                rv = PR_SUCCESS;
            else
                rv = PR_FAILURE;
        } else
            rv = PR_FAILURE;
        (void)PR_UnloadLibrary(lib);
    } else
        rv = PR_FAILURE;
    return rv;
}
#endif

#if defined(_PR_INET6) && defined(_PR_HAVE_GETHOSTBYNAME2)
/*
** Append the V4 addresses to the end of the list
*/
static PRStatus AppendV4AddrsToHostent(
    struct hostent *from,
    char **buf,
    PRIntn *bufsize,
    PRHostEnt *to)
{
    PRIntn na, na_old;
    char **ap;
    char **new_addr_list;
			
    /* Count the addresses, then grow storage for the pointers */
    for (na_old = 0, ap = to->h_addr_list; *ap != 0; na_old++, ap++)
        {;} /* nothing to execute */
    for (na = na_old + 1, ap = from->h_addr_list; *ap != 0; na++, ap++)
        {;} /* nothing to execute */
    new_addr_list = (char**)Alloc(
        na * sizeof(char*), buf, bufsize, sizeof(char**));
    if (!new_addr_list) return PR_FAILURE;

    /* Copy the V6 addresses, one at a time */
    for (na = 0, ap = to->h_addr_list; *ap != 0; na++, ap++) {
        new_addr_list[na] = to->h_addr_list[na];
    }
    to->h_addr_list = new_addr_list;

    /* Copy the V4 addresses, one at a time */
    for (ap = from->h_addr_list; *ap != 0; na++, ap++) {
        to->h_addr_list[na] = Alloc(to->h_length, buf, bufsize, 0);
        if (!to->h_addr_list[na]) return PR_FAILURE;
        MakeIPv4MappedAddr(*ap, to->h_addr_list[na]);
    }
    to->h_addr_list[na] = 0;
    return PR_SUCCESS;
}
#endif

PR_IMPLEMENT(PRStatus) PR_GetIPNodeByNameExtended(
    const char *name, PRUint16 af, PRIntn flags,
    char *buf, PRIntn bufsize, PRHostEnt *hp)
{
	struct hostent *h = 0;
	PRStatus rv = PR_FAILURE;
#if defined(_PR_HAVE_GETHOST_R)
    char localbuf[PR_NETDB_BUF_SIZE];
    char *tmpbuf;
    struct hostent tmphe;
    int h_err;
#endif
#if defined(_PR_HAVE_GETIPNODEBYNAME)
	PRUint16 md_af = af;
	int error_num;
	int tmp_flags = 0;
#endif
#if defined(_PR_HAVE_GETHOSTBYNAME2)
    PRBool did_af_inet = PR_FALSE;
#endif

    DNSSECFUNDEBUG((stderr, "input=%s\n", name));
    if (!_pr_initialized) _PR_ImplicitInitialization();

    if (af != PR_AF_INET && af != PR_AF_INET6) {
        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
        DNSSECFUNRETURN(PR_FAILURE);
    }

#if defined(_PR_INET6) && defined(_PR_HAVE_GETHOSTBYNAME2)
    PR_Lock(_pr_query_ifs_lock);
    /*
     * Keep querying the presence of IPv4 and IPv6 interfaces until
     * at least one is up.  This allows us to detect the local
     * machine going from offline to online.
     */
    if (!_pr_have_inet_if && !_pr_have_inet6_if) {
	_pr_QueryNetIfs();
#ifdef DEBUG_QUERY_IFS
	if (_pr_have_inet_if)
		printf("Have IPv4 source address\n");
	if (_pr_have_inet6_if)
		printf("Have IPv6 source address\n");
#endif
    }
    PR_Unlock(_pr_query_ifs_lock);
#endif

#if defined(_PR_HAVE_GETIPNODEBYNAME)
	if (flags & PR_AI_V4MAPPED)
		tmp_flags |= AI_V4MAPPED;
	if (flags & PR_AI_ADDRCONFIG)
		tmp_flags |= AI_ADDRCONFIG;
	if (flags & PR_AI_ALL)
		tmp_flags |= AI_ALL;
    if (af == PR_AF_INET6)
    	md_af = AF_INET6;
	else
    	md_af = af;
#endif

#if defined(_PR_HAVE_GETHOST_R)
    tmpbuf = localbuf;
    if (bufsize > sizeof(localbuf))
    {
        tmpbuf = (char *)PR_Malloc(bufsize);
        if (NULL == tmpbuf)
        {
            PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
            DNSSECFUNRETURN(rv);
        }
    }
#endif

    /* XXX: should be able to map gethostbyname2 -> getaddrinfo with hints */

    /* Do not need to lock the DNS lock if getipnodebyname() is called */
#ifdef _PR_INET6
#ifdef _PR_HAVE_GETHOSTBYNAME2
    LOCK_DNS();
    if (af == PR_AF_INET6)
    {
        if ((flags & PR_AI_ADDRCONFIG) == 0 || _pr_have_inet6_if)
        {
#ifdef _PR_INET6_PROBE
          if (_pr_ipv6_is_present == PR_TRUE)
#endif
            h = GETHOSTBYNAME2(name, AF_INET6); 
        }
        if ((NULL == h) && (flags & PR_AI_V4MAPPED)
        && ((flags & PR_AI_ADDRCONFIG) == 0 || _pr_have_inet_if))
        {
            did_af_inet = PR_TRUE;
            h = GETHOSTBYNAME2(name, AF_INET);
        }
    }
    else
    {
        if ((flags & PR_AI_ADDRCONFIG) == 0 || _pr_have_inet_if)
        {
            did_af_inet = PR_TRUE;
            h = GETHOSTBYNAME2(name, af);
        }
    }
#elif defined(_PR_HAVE_GETIPNODEBYNAME)
    h = getipnodebyname(name, md_af, tmp_flags, &error_num);
#else
#error "Unknown name-to-address translation function"
#endif	/* _PR_HAVE_GETHOSTBYNAME2 */
#elif defined(_PR_INET6_PROBE) && defined(_PR_HAVE_GETIPNODEBYNAME)
    if (_pr_ipv6_is_present == PR_TRUE)
    {
#ifdef PR_GETIPNODE_NOT_THREADSAFE
        LOCK_DNS();
#endif
    	h = (*((_pr_getipnodebyname_t)_pr_getipnodebyname_fp))(name, md_af, tmp_flags, &error_num);
    }
    else
    {
        LOCK_DNS();
    	h = GETHOSTBYNAME(name);
    }
#else /* _PR_INET6 */
    LOCK_DNS();
#ifdef XP_OS2_VACPP
    h = GETHOSTBYNAME((char *)name);
#else
    h = GETHOSTBYNAME(name);
#endif
#endif /* _PR_INET6 */
    
	if (NULL == h)
	{
      DNSSECDEBUG((stderr, "  lookup failed\n"));
#if defined(_PR_INET6) && defined(_PR_HAVE_GETIPNODEBYNAME)
	    PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, error_num);
#elif defined(_PR_INET6_PROBE) && defined(_PR_HAVE_GETIPNODEBYNAME)
    	if (_pr_ipv6_is_present == PR_TRUE)
	    	PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, error_num);
		else
	    	PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_GETHOST_ERRNO());
#else
	    PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_GETHOST_ERRNO());
#endif
	}
	else
	{
		_PRIPAddrConversion conversion = _PRIPAddrNoConversion;

		if (af == PR_AF_INET6) conversion = _PRIPAddrIPv4Mapped;
		rv = CopyHostent(h, &buf, &bufsize, conversion, hp);
		if (PR_SUCCESS != rv)
		    PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, 0);
#if defined(_PR_INET6) && defined(_PR_HAVE_GETIPNODEBYNAME)
		freehostent(h);
#elif defined(_PR_INET6_PROBE) && defined(_PR_HAVE_GETIPNODEBYNAME)
    	if (_pr_ipv6_is_present == PR_TRUE)
			(*((_pr_freehostent_t)_pr_freehostent_fp))(h);
#endif
#if defined(_PR_INET6) && defined(_PR_HAVE_GETHOSTBYNAME2)
		if ((PR_SUCCESS == rv) && (flags & PR_AI_V4MAPPED)
				&& ((flags & PR_AI_ALL)
				|| ((flags & PR_AI_ADDRCONFIG) && _pr_have_inet_if))
				&& !did_af_inet && (h = GETHOSTBYNAME2(name, AF_INET)) != 0) {
			rv = AppendV4AddrsToHostent(h, &buf, &bufsize, hp);
			if (PR_SUCCESS != rv)
				PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, 0);
		}
#endif
	}

    /* Must match the convoluted logic above for LOCK_DNS() */
#ifdef _PR_INET6
#ifdef _PR_HAVE_GETHOSTBYNAME2
    UNLOCK_DNS();
#endif	/* _PR_HAVE_GETHOSTBYNAME2 */
#elif defined(_PR_INET6_PROBE) && defined(_PR_HAVE_GETIPNODEBYNAME)
#ifdef PR_GETIPNODE_NOT_THREADSAFE
    UNLOCK_DNS();
#else
    if (_pr_ipv6_is_present == PR_FALSE)
        UNLOCK_DNS();
#endif
#else /* _PR_INET6 */
    UNLOCK_DNS();
#endif /* _PR_INET6 */

#if defined(_PR_HAVE_GETHOST_R)
    if (tmpbuf != localbuf)
        PR_Free(tmpbuf);
#endif

    DNSSECFUNRETURN(rv);
}

PR_IMPLEMENT(PRStatus) PR_GetIPNodeByName(
    const char *name, PRUint16 af, PRIntn flags,
    char *buf, PRIntn bufsize, PRHostEnt *hp)
{
  PRStatus ret;
  DNSSECFUNDEBUG((stderr, "input=%s\n", name));
  ret = PR_GetIPNodeByName(name, af, flags, buf, bufsize, hp);
  simplify_return_value();
  return ret;
}

PR_IMPLEMENT(PRStatus) PR_GetHostByAddr(
    const PRNetAddr *hostaddr, char *buf, PRIntn bufsize, PRHostEnt *hostentry)
{
	struct hostent *h;
	PRStatus rv = PR_FAILURE;
	const void *addr;
	PRUint32 tmp_ip;
	int addrlen;
	PRInt32 af;
#if defined(_PR_HAVE_GETHOST_R)
    char localbuf[PR_NETDB_BUF_SIZE];
    char *tmpbuf;
    struct hostent tmphe;
    int h_err;
#endif
#if defined(_PR_HAVE_GETIPNODEBYADDR)
	int error_num;
#endif

    DNSSECFUNDEBUG((stderr, "input=%x", (unsigned int) hostaddr));
    if (!_pr_initialized) _PR_ImplicitInitialization();

	if (hostaddr->raw.family == PR_AF_INET6)
	{
#if defined(_PR_INET6_PROBE)
		if (_pr_ipv6_is_present == PR_TRUE)
			af = AF_INET6;
		else
			af = AF_INET;
#elif defined(_PR_INET6)
		af = AF_INET6;
#else
		af = AF_INET;
#endif
#if defined(_PR_GHBA_DISALLOW_V4MAPPED)
		if (_PR_IN6_IS_ADDR_V4MAPPED(&hostaddr->ipv6.ip))
			af = AF_INET;
#endif
	}
	else
	{
		PR_ASSERT(hostaddr->raw.family == AF_INET);
		af = AF_INET;
	}
	if (hostaddr->raw.family == PR_AF_INET6) {
#if defined(_PR_INET6) || defined(_PR_INET6_PROBE)
		if (af == AF_INET6) {
			addr = &hostaddr->ipv6.ip;
			addrlen = sizeof(hostaddr->ipv6.ip);
		}
		else
#endif
		{
			PR_ASSERT(af == AF_INET);
			if (!_PR_IN6_IS_ADDR_V4MAPPED(&hostaddr->ipv6.ip)) {
				PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
				return rv;
			}
			tmp_ip = _PR_IN6_V4MAPPED_TO_IPADDR((PRIPv6Addr *)
												&hostaddr->ipv6.ip);
			addr = &tmp_ip;
			addrlen = sizeof(tmp_ip);
		}
	} else {
		PR_ASSERT(hostaddr->raw.family == AF_INET);
		PR_ASSERT(af == AF_INET);
		addr = &hostaddr->inet.ip;
		addrlen = sizeof(hostaddr->inet.ip);
	}

#if defined(_PR_HAVE_GETHOST_R)
    tmpbuf = localbuf;
    if (bufsize > sizeof(localbuf))
    {
        tmpbuf = (char *)PR_Malloc(bufsize);
        if (NULL == tmpbuf)
        {
            PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
            return rv;
        }
    }
#endif

    /* Do not need to lock the DNS lock if getipnodebyaddr() is called */
#if defined(_PR_HAVE_GETIPNODEBYADDR) && defined(_PR_INET6)
	h = getipnodebyaddr(addr, addrlen, af, &error_num);
#elif defined(_PR_HAVE_GETIPNODEBYADDR) && defined(_PR_INET6_PROBE)
    if (_pr_ipv6_is_present == PR_TRUE)
    {
#ifdef PR_GETIPNODE_NOT_THREADSAFE
        LOCK_DNS();
#endif
    	h = (*((_pr_getipnodebyaddr_t)_pr_getipnodebyaddr_fp))(addr, addrlen,
				af, &error_num);
    }
	else
    {
        LOCK_DNS();
		h = GETHOSTBYADDR(addr, addrlen, af);
    }
#else	/* _PR_HAVE_GETIPNODEBYADDR */
    LOCK_DNS();
#ifdef XP_OS2_VACPP
	h = GETHOSTBYADDR((char *)addr, addrlen, af);
#else
	h = GETHOSTBYADDR(addr, addrlen, af);
#endif
#endif /* _PR_HAVE_GETIPNODEBYADDR */
	if (NULL == h)
	{
#if defined(_PR_INET6) && defined(_PR_HAVE_GETIPNODEBYADDR)
		PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, error_num);
#elif defined(_PR_INET6_PROBE) && defined(_PR_HAVE_GETIPNODEBYADDR)
    	if (_pr_ipv6_is_present == PR_TRUE)
	    	PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, error_num);
		else
	    	PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_GETHOST_ERRNO());
#else
		PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_GETHOST_ERRNO());
#endif
	}
	else
	{
		_PRIPAddrConversion conversion = _PRIPAddrNoConversion;
		if (hostaddr->raw.family == PR_AF_INET6) {
			if (af == AF_INET) {
				if (_PR_IN6_IS_ADDR_V4MAPPED((PRIPv6Addr*)
												&hostaddr->ipv6.ip)) {
					conversion = _PRIPAddrIPv4Mapped;
				} else if (_PR_IN6_IS_ADDR_V4COMPAT((PRIPv6Addr *)
													&hostaddr->ipv6.ip)) {
					conversion = _PRIPAddrIPv4Compat;
				}
			}
		}
		rv = CopyHostent(h, &buf, &bufsize, conversion, hostentry);
		if (PR_SUCCESS != rv) {
		    PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, 0);
		}
#if defined(_PR_INET6) && defined(_PR_HAVE_GETIPNODEBYADDR)
		freehostent(h);
#elif defined(_PR_INET6_PROBE) && defined(_PR_HAVE_GETIPNODEBYADDR)
    	if (_pr_ipv6_is_present == PR_TRUE)
			(*((_pr_freehostent_t)_pr_freehostent_fp))(h);
#endif
	}

    /* Must match the convoluted logic above for LOCK_DNS() */
#if defined(_PR_HAVE_GETIPNODEBYADDR) && defined(_PR_INET6)
#elif defined(_PR_HAVE_GETIPNODEBYADDR) && defined(_PR_INET6_PROBE)
#ifdef PR_GETIPNODE_NOT_THREADSAFE
    UNLOCK_DNS();
#else
    if (_pr_ipv6_is_present == PR_FALSE)
        UNLOCK_DNS();
#endif
#else	/* _PR_HAVE_GETIPNODEBYADDR */
    UNLOCK_DNS();
#endif /* _PR_HAVE_GETIPNODEBYADDR */

#if defined(_PR_HAVE_GETHOST_R)
    if (tmpbuf != localbuf)
        PR_Free(tmpbuf);
#endif

	DNSSECFUNRETURN(rv);
}

/******************************************************************************/
/*
 * Some systems define a reentrant version of getprotobyname(). Too bad
 * the signature isn't always the same. But hey, they tried. If there
 * is such a definition, use it. Otherwise, grab a lock and do it here.
 */
/******************************************************************************/

#if !defined(_PR_HAVE_GETPROTO_R)
/*
 * This may seem like a silly thing to do, but the compiler SHOULD
 * complain if getprotobyname_r() is implemented on some system and
 * we're not using it. For sure these signatures are different than
 * any usable implementation.
 */

static struct protoent *getprotobyname_r(const char* name)
{
#ifdef XP_OS2_VACPP
	return getprotobyname((char *)name);
#else
	return getprotobyname(name);
#endif
} /* getprotobyname_r */

static struct protoent *getprotobynumber_r(PRInt32 number)
{
	return getprotobynumber(number);
} /* getprotobynumber_r */

#endif /* !defined(_PR_HAVE_GETPROTO_R) */

PR_IMPLEMENT(PRStatus) PR_GetProtoByName(
    const char* name, char* buffer, PRInt32 buflen, PRProtoEnt* result)
{
	PRStatus rv = PR_SUCCESS;
#if defined(_PR_HAVE_GETPROTO_R)
	struct protoent* res = (struct protoent*)result;
#endif

    if (!_pr_initialized) _PR_ImplicitInitialization();

#if defined(_PR_HAVE_GETPROTO_R_INT)
    {
        /*
        ** The protoent_data has a pointer as the first field.
        ** That implies the buffer better be aligned, and char*
        ** doesn't promise much.
        */
        PRUptrdiff aligned = (PRUptrdiff)buffer;
        if (0 != (aligned & (sizeof(struct protoent_data*) - 1)))
        {
            aligned += sizeof(struct protoent_data*) - 1;
            aligned &= ~(sizeof(struct protoent_data*) - 1);
            buflen -= (aligned - (PRUptrdiff)buffer);
            buffer = (char*)aligned;
        }
    }
#endif  /* defined(_PR_HAVE_GETPROTO_R_INT) */

    if (PR_NETDB_BUF_SIZE > buflen)
    {
        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
        return PR_FAILURE;
    }

#if defined(_PR_HAVE_GETPROTO_R_POINTER)
    if (NULL == getprotobyname_r(name, res, buffer, buflen))
    {
        PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_ERRNO());
        return PR_FAILURE;
    }
#elif defined(_PR_HAVE_GETPROTO_R_INT)
    /*
    ** The buffer needs to be zero'd, and it should be
    ** at least the size of a struct protoent_data.
    */
    memset(buffer, 0, buflen);
	if (-1 == getprotobyname_r(name, res, (struct protoent_data*)buffer))
    {
        PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_ERRNO());
        return PR_FAILURE;
    }
#elif defined(_PR_HAVE_5_ARG_GETPROTO_R)
    /* The 5th argument for getprotobyname_r() cannot be NULL */
    if (-1 == getprotobyname_r(name, res, buffer, buflen, &res))
    {
        PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_ERRNO());
        return PR_FAILURE;
    }
#else  /* do it the hard way */
	{
		struct protoent *staticBuf;
		PR_Lock(_getproto_lock);
		staticBuf = getprotobyname_r(name);
		if (NULL == staticBuf)
		{
		    rv = PR_FAILURE;
		    PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_ERRNO());
        }
		else
		{
			rv = CopyProtoent(staticBuf, buffer, buflen, result);
			if (PR_FAILURE == rv)
			    PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, 0);
        }
		PR_Unlock(_getproto_lock);
	}
#endif  /* all that */
    return rv;
}

PR_IMPLEMENT(PRStatus) PR_GetProtoByNumber(
    PRInt32 number, char* buffer, PRInt32 buflen, PRProtoEnt* result)
{
	PRStatus rv = PR_SUCCESS;
#if defined(_PR_HAVE_GETPROTO_R)
	struct protoent* res = (struct protoent*)result;
#endif

    if (!_pr_initialized) _PR_ImplicitInitialization();

#if defined(_PR_HAVE_GETPROTO_R_INT)
    {
        /*
        ** The protoent_data has a pointer as the first field.
        ** That implies the buffer better be aligned, and char*
        ** doesn't promise much.
        */
        PRUptrdiff aligned = (PRUptrdiff)buffer;
        if (0 != (aligned & (sizeof(struct protoent_data*) - 1)))
        {
            aligned += sizeof(struct protoent_data*) - 1;
            aligned &= ~(sizeof(struct protoent_data*) - 1);
            buflen -= (aligned - (PRUptrdiff)buffer);
            buffer = (char*)aligned;
        }
    }
#endif /* defined(_PR_HAVE_GETPROTO_R_INT) */

    if (PR_NETDB_BUF_SIZE > buflen)
    {
        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
        return PR_FAILURE;
    }

#if defined(_PR_HAVE_GETPROTO_R_POINTER)
    if (NULL == getprotobynumber_r(number, res, buffer, buflen))
    {
        PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_ERRNO());
        return PR_FAILURE;
    }

#elif defined(_PR_HAVE_GETPROTO_R_INT)
    /*
    ** The buffer needs to be zero'd for these OS's.
    */
    memset(buffer, 0, buflen);
	if (-1 == getprotobynumber_r(number, res, (struct protoent_data*)buffer))
    {
        PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_ERRNO());
        return PR_FAILURE;
    }
#elif defined(_PR_HAVE_5_ARG_GETPROTO_R)
    /* The 5th argument for getprotobynumber_r() cannot be NULL */
    if (-1 == getprotobynumber_r(number, res, buffer, buflen, &res))
    {
        PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_ERRNO());
        return PR_FAILURE;
    }
#else  /* do it the hard way */
	{
		struct protoent *staticBuf;
		PR_Lock(_getproto_lock);
		staticBuf = getprotobynumber_r(number);
		if (NULL == staticBuf)
		{
		    rv = PR_FAILURE;
		    PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_ERRNO());
        }
		else
		{
			rv = CopyProtoent(staticBuf, buffer, buflen, result);
			if (PR_FAILURE == rv)
			    PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, 0);
        }
		PR_Unlock(_getproto_lock);
	}
#endif  /* all that crap */
    return rv;

}

PRUintn _PR_NetAddrSize(const PRNetAddr* addr)
{
    PRUintn addrsize;

    /*
     * RFC 2553 added a new field (sin6_scope_id) to
     * struct sockaddr_in6.  PRNetAddr's ipv6 member has a
     * scope_id field to match the new field.  In order to
     * work with older implementations supporting RFC 2133,
     * we take the size of struct sockaddr_in6 instead of
     * addr->ipv6.
     */
    if (AF_INET == addr->raw.family)
        addrsize = sizeof(addr->inet);
    else if (PR_AF_INET6 == addr->raw.family)
#if defined(_PR_INET6)
        addrsize = sizeof(struct sockaddr_in6);
#else
        addrsize = sizeof(addr->ipv6);
#endif
#if defined(XP_UNIX) || defined(XP_OS2_EMX)
    else if (AF_UNIX == addr->raw.family)
        addrsize = sizeof(addr->local);
#endif
    else addrsize = 0;

    return addrsize;
}  /* _PR_NetAddrSize */

PR_IMPLEMENT(PRIntn) PR_EnumerateHostEnt(
    PRIntn enumIndex, const PRHostEnt *hostEnt, PRUint16 port, PRNetAddr *address)
{
    void *addr = hostEnt->h_addr_list[enumIndex++];
    memset(address, 0, sizeof(PRNetAddr));
    if (NULL == addr) enumIndex = 0;
    else
    {
        address->raw.family = hostEnt->h_addrtype;
        if (PR_AF_INET6 == hostEnt->h_addrtype)
        {
            address->ipv6.port = htons(port);
        	address->ipv6.flowinfo = 0;
        	address->ipv6.scope_id = 0;
            memcpy(&address->ipv6.ip, addr, hostEnt->h_length);
        }
        else
        {
            PR_ASSERT(AF_INET == hostEnt->h_addrtype);
            address->inet.port = htons(port);
            memcpy(&address->inet.ip, addr, hostEnt->h_length);
        }
    }
    return enumIndex;
}  /* PR_EnumerateHostEnt */

PR_IMPLEMENT(PRStatus) PR_InitializeNetAddr(
    PRNetAddrValue val, PRUint16 port, PRNetAddr *addr)
{
    PRStatus rv = PR_SUCCESS;
    if (!_pr_initialized) _PR_ImplicitInitialization();

	if (val != PR_IpAddrNull) memset(addr, 0, sizeof(addr->inet));
	addr->inet.family = AF_INET;
	addr->inet.port = htons(port);
	switch (val)
	{
	case PR_IpAddrNull:
		break;  /* don't overwrite the address */
	case PR_IpAddrAny:
		addr->inet.ip = htonl(INADDR_ANY);
		break;
	case PR_IpAddrLoopback:
		addr->inet.ip = htonl(INADDR_LOOPBACK);
		break;
	default:
		PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
		rv = PR_FAILURE;
	}
    return rv;
}  /* PR_InitializeNetAddr */

PR_IMPLEMENT(PRStatus) PR_SetNetAddr(
    PRNetAddrValue val, PRUint16 af, PRUint16 port, PRNetAddr *addr)
{
    PRStatus rv = PR_SUCCESS;
    if (!_pr_initialized) _PR_ImplicitInitialization();

    if (af == PR_AF_INET6)
    {
        if (val != PR_IpAddrNull) memset(addr, 0, sizeof(addr->ipv6));
        addr->ipv6.family = af;
        addr->ipv6.port = htons(port);
        addr->ipv6.flowinfo = 0;
        addr->ipv6.scope_id = 0;
        switch (val)
        {
        case PR_IpAddrNull:
            break;  /* don't overwrite the address */
        case PR_IpAddrAny:
            addr->ipv6.ip = _pr_in6addr_any;
            break;
        case PR_IpAddrLoopback:
            addr->ipv6.ip = _pr_in6addr_loopback;
            break;
        default:
            PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
            rv = PR_FAILURE;
        }
    }
    else
    {
        if (val != PR_IpAddrNull) memset(addr, 0, sizeof(addr->inet));
        addr->inet.family = af;
        addr->inet.port = htons(port);
        switch (val)
        {
        case PR_IpAddrNull:
            break;  /* don't overwrite the address */
        case PR_IpAddrAny:
            addr->inet.ip = htonl(INADDR_ANY);
            break;
        case PR_IpAddrLoopback:
            addr->inet.ip = htonl(INADDR_LOOPBACK);
            break;
        default:
            PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
            rv = PR_FAILURE;
        }
    }
    return rv;
}  /* PR_SetNetAddr */

PR_IMPLEMENT(PRBool)
PR_IsNetAddrType(const PRNetAddr *addr, PRNetAddrValue val)
{
    if (addr->raw.family == PR_AF_INET6) {
        if (val == PR_IpAddrAny) {
			if (_PR_IN6_IS_ADDR_UNSPECIFIED((PRIPv6Addr *)&addr->ipv6.ip)) {
            	return PR_TRUE;
			} else if (_PR_IN6_IS_ADDR_V4MAPPED((PRIPv6Addr *)&addr->ipv6.ip)
					&& _PR_IN6_V4MAPPED_TO_IPADDR((PRIPv6Addr *)&addr->ipv6.ip)
							== htonl(INADDR_ANY)) {
            	return PR_TRUE;
			}
        } else if (val == PR_IpAddrLoopback) {
            if (_PR_IN6_IS_ADDR_LOOPBACK((PRIPv6Addr *)&addr->ipv6.ip)) {
            	return PR_TRUE;
			} else if (_PR_IN6_IS_ADDR_V4MAPPED((PRIPv6Addr *)&addr->ipv6.ip)
					&& _PR_IN6_V4MAPPED_TO_IPADDR((PRIPv6Addr *)&addr->ipv6.ip)
							== htonl(INADDR_LOOPBACK)) {
            	return PR_TRUE;
			}
        } else if (val == PR_IpAddrV4Mapped
                && _PR_IN6_IS_ADDR_V4MAPPED((PRIPv6Addr *)&addr->ipv6.ip)) {
            return PR_TRUE;
        }
    } else {
        if (addr->raw.family == AF_INET) {
            if (val == PR_IpAddrAny && addr->inet.ip == htonl(INADDR_ANY)) {
                return PR_TRUE;
            } else if (val == PR_IpAddrLoopback
                    && addr->inet.ip == htonl(INADDR_LOOPBACK)) {
                return PR_TRUE;
            }
        }
    }
    return PR_FALSE;
}

#ifndef _PR_HAVE_INET_NTOP
#define XX 127
static const unsigned char index_hex[256] = {
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
     0, 1, 2, 3,  4, 5, 6, 7,  8, 9,XX,XX, XX,XX,XX,XX,
    XX,10,11,12, 13,14,15,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,10,11,12, 13,14,15,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
};

/*
 * StringToV6Addr() returns 1 if the conversion succeeds,
 * or 0 if the input is not a valid IPv6 address string.
 * (Same as inet_pton(AF_INET6, string, addr).)
 */
static int StringToV6Addr(const char *string, PRIPv6Addr *addr)
{
    const unsigned char *s = (const unsigned char *)string;
    int section = 0;        /* index of the current section (a 16-bit
                             * piece of the address */
    int double_colon = -1;  /* index of the section after the first
                             * 16-bit group of zeros represented by
                             * the double colon */
    unsigned int val;
    int len;

    /* Handle initial (double) colon */
    if (*s == ':') {
        if (s[1] != ':') return 0;
        s += 2;
        addr->pr_s6_addr16[0] = 0;
        section = double_colon = 1;
    }

    while (*s) {
        if (section == 8) return 0; /* too long */
        if (*s == ':') {
            if (double_colon != -1) return 0; /* two double colons */
            addr->pr_s6_addr16[section++] = 0;
            double_colon = section;
            s++;
            continue;
        }
        for (len = val = 0; len < 4 && index_hex[*s] != XX; len++) {
            val = (val << 4) + index_hex[*s++];
        }
        if (*s == '.') {
            if (len == 0) return 0; /* nothing between : and . */
            break;
        }
        if (*s == ':') {
            s++;
            if (!*s) return 0; /* cannot end with single colon */
        } else if (*s) {
            return 0; /* bad character */
        }
        addr->pr_s6_addr16[section++] = htons((unsigned short)val);
    }
    
    if (*s == '.') {
        /* Have a trailing v4 format address */
        if (section > 6) return 0; /* not enough room */

        /*
         * The number before the '.' is decimal, but we parsed it
         * as hex.  That means it is in BCD.  Check it for validity
         * and convert it to binary.
         */
        if (val > 0x0255 || (val & 0xf0) > 0x90 || (val & 0xf) > 9) return 0;
        val = (val >> 8) * 100 + ((val >> 4) & 0xf) * 10 + (val & 0xf);
        addr->pr_s6_addr[2 * section] = val;

        s++;
        val = index_hex[*s++];
        if (val > 9) return 0;
        while (*s >= '0' && *s <= '9') {
            val = val * 10 + *s++ - '0';
            if (val > 255) return 0;
        }
        if (*s != '.') return 0; /* must have exactly 4 decimal numbers */
        addr->pr_s6_addr[2 * section + 1] = val;
        section++;

        s++;
        val = index_hex[*s++];
        if (val > 9) return 0;
        while (*s >= '0' && *s <= '9') {
            val = val * 10 + *s++ - '0';
            if (val > 255) return 0;
        }
        if (*s != '.') return 0; /* must have exactly 4 decimal numbers */
        addr->pr_s6_addr[2 * section] = val;

        s++;
        val = index_hex[*s++];
        if (val > 9) return 0;
        while (*s >= '0' && *s <= '9') {
            val = val * 10 + *s++ - '0';
            if (val > 255) return 0;
        }
        if (*s) return 0; /* must have exactly 4 decimal numbers */
        addr->pr_s6_addr[2 * section + 1] = val;
        section++;
    }
    
    if (double_colon != -1) {
        /* Stretch the double colon */
        int tosection;
        int ncopy = section - double_colon;
        for (tosection = 7; ncopy--; tosection--) {
            addr->pr_s6_addr16[tosection] = 
                addr->pr_s6_addr16[double_colon + ncopy];
        }
        while (tosection >= double_colon) {
            addr->pr_s6_addr16[tosection--] = 0;
        }
    } else if (section != 8) {
        return 0; /* too short */
    }
    return 1;
}
#undef XX
            
static const char *basis_hex = "0123456789abcdef";

/*
 * V6AddrToString() returns a pointer to the buffer containing
 * the text string if the conversion succeeds, and NULL otherwise.
 * (Same as inet_ntop(AF_INET6, addr, buf, size), except that errno
 * is not set on failure.)
 */
static const char *V6AddrToString(
    const PRIPv6Addr *addr, char *buf, PRUint32 size)
{
#define STUFF(c) do { \
    if (!size--) return NULL; \
    *buf++ = (c); \
} while (0)

    int double_colon = -1;          /* index of the first 16-bit
                                     * group of zeros represented
                                     * by the double colon */
    int double_colon_length = 1;    /* use double colon only if
                                     * there are two or more 16-bit
                                     * groups of zeros */
    int zero_length;
    int section;
    unsigned int val;
    const char *bufcopy = buf;

    /* Scan to find the placement of the double colon */
    for (section = 0; section < 8; section++) {
        if (addr->pr_s6_addr16[section] == 0) {
            zero_length = 1;
            section++;
            while (section < 8 && addr->pr_s6_addr16[section] == 0) {
                zero_length++;
                section++;
            }
            /* Select the longest sequence of zeros */
            if (zero_length > double_colon_length) {
                double_colon = section - zero_length;
                double_colon_length = zero_length;
            }
        }
    }

    /* Now start converting to a string */
    section = 0;

    if (double_colon == 0) {
        if (double_colon_length == 6 ||
            (double_colon_length == 5 && addr->pr_s6_addr16[5] == 0xffff)) {
            /* ipv4 format address */
            STUFF(':');
            STUFF(':');
            if (double_colon_length == 5) {
                STUFF('f');
                STUFF('f');
                STUFF('f');
                STUFF('f');
                STUFF(':');
            }
            if (addr->pr_s6_addr[12] > 99) STUFF(addr->pr_s6_addr[12]/100 + '0');
            if (addr->pr_s6_addr[12] > 9) STUFF((addr->pr_s6_addr[12]%100)/10 + '0');
            STUFF(addr->pr_s6_addr[12]%10 + '0');
            STUFF('.');
            if (addr->pr_s6_addr[13] > 99) STUFF(addr->pr_s6_addr[13]/100 + '0');
            if (addr->pr_s6_addr[13] > 9) STUFF((addr->pr_s6_addr[13]%100)/10 + '0');
            STUFF(addr->pr_s6_addr[13]%10 + '0');
            STUFF('.');
            if (addr->pr_s6_addr[14] > 99) STUFF(addr->pr_s6_addr[14]/100 + '0');
            if (addr->pr_s6_addr[14] > 9) STUFF((addr->pr_s6_addr[14]%100)/10 + '0');
            STUFF(addr->pr_s6_addr[14]%10 + '0');
            STUFF('.');
            if (addr->pr_s6_addr[15] > 99) STUFF(addr->pr_s6_addr[15]/100 + '0');
            if (addr->pr_s6_addr[15] > 9) STUFF((addr->pr_s6_addr[15]%100)/10 + '0');
            STUFF(addr->pr_s6_addr[15]%10 + '0');
            STUFF('\0');
            return bufcopy;
        }
    }

    while (section < 8) {
        if (section == double_colon) {
            STUFF(':');
            STUFF(':');
            section += double_colon_length;
            continue;
        }
        val = ntohs(addr->pr_s6_addr16[section]);
        if (val > 0xfff) {
            STUFF(basis_hex[val >> 12]);
        }
        if (val > 0xff) {
            STUFF(basis_hex[(val >> 8) & 0xf]);
        }
        if (val > 0xf) {
            STUFF(basis_hex[(val >> 4) & 0xf]);
        }
        STUFF(basis_hex[val & 0xf]);
        section++;
        if (section < 8 && section != double_colon) STUFF(':');
    }
    STUFF('\0');
    return bufcopy;
#undef STUFF    
}

#endif /* !_PR_HAVE_INET_NTOP */

PR_IMPLEMENT(PRStatus) PR_StringToNetAddr(const char *string, PRNetAddr *addr)
{
    PRStatus status = PR_SUCCESS;
    PRIntn rv;

    DNSSECFUNDEBUG((stderr,"input=%s\n",string));
#if defined(_PR_HAVE_INET_NTOP)
    rv = inet_pton(AF_INET6, string, &addr->ipv6.ip);
    if (1 == rv)
    {
        addr->raw.family = PR_AF_INET6;
    }
    else
    {
        PR_ASSERT(0 == rv);
        /* clean up after the failed inet_pton() call */
        memset(&addr->ipv6.ip, 0, sizeof(addr->ipv6.ip));
        /* XXX */
        LOCK_DNS();
        rv = inet_pton(AF_INET, string, &addr->inet.ip);
        if (1 == rv)
        {
          addr->raw.family = AF_INET;
        }
        else
        {
          PR_ASSERT(0 == rv);
          PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
          status = PR_FAILURE;
        }
        UNLOCK_DNS();
    }
#else /* _PR_HAVE_INET_NTOP */
    rv = StringToV6Addr(string, &addr->ipv6.ip);
    if (1 == rv) {
        addr->raw.family = PR_AF_INET6;
        DNSSECFUNRETURN(PR_SUCCESS);
    }
    PR_ASSERT(0 == rv);
    /* clean up after the failed StringToV6Addr() call */
    memset(&addr->ipv6.ip, 0, sizeof(addr->ipv6.ip));

    addr->inet.family = AF_INET;
#ifdef XP_OS2_VACPP
    addr->inet.ip = inet_addr((char *)string);
#else
    addr->inet.ip = inet_addr(string);
#endif
    if ((PRUint32) -1 == addr->inet.ip)
    {
        /*
         * The string argument is a malformed address string.
         */
        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
        status = PR_FAILURE;
    }
#endif /* _PR_HAVE_INET_NTOP */

    DNSSECFUNRETURN(status);
}

PR_IMPLEMENT(PRStatus) PR_NetAddrToString(
    const PRNetAddr *addr, char *string, PRUint32 size)
{
    if (PR_AF_INET6 == addr->raw.family)
    {
#if defined(_PR_HAVE_INET_NTOP)
        if (NULL == inet_ntop(AF_INET6, &addr->ipv6.ip, string, size))
#else
        if (NULL == V6AddrToString(&addr->ipv6.ip, string, size))
#endif
        {
            /* the size of the result buffer is inadequate */
            PR_SetError(PR_BUFFER_OVERFLOW_ERROR, 0);
            return PR_FAILURE;
        }
    }
    else
    {
        if (size < 16) goto failed;
        if (AF_INET != addr->raw.family) goto failed;
        else
        {
            unsigned char *byte = (unsigned char*)&addr->inet.ip;
            PR_snprintf(string, size, "%u.%u.%u.%u",
                byte[0], byte[1], byte[2], byte[3]);
        }
    }

    return PR_SUCCESS;

failed:
    PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
    return PR_FAILURE;

}  /* PR_NetAddrToString */

/*
 * Convert an IPv4 addr to an (IPv4-mapped) IPv6 addr
 */
PR_IMPLEMENT(void) PR_ConvertIPv4AddrToIPv6(PRUint32 v4addr, PRIPv6Addr *v6addr)
{
    PRUint8 *dstp;
    dstp = v6addr->pr_s6_addr;
    memset(dstp, 0, 10);
    memset(dstp + 10, 0xff, 2);
    memcpy(dstp + 12,(char *) &v4addr, 4);
}

PR_IMPLEMENT(PRUint16) PR_ntohs(PRUint16 n) { return ntohs(n); }
PR_IMPLEMENT(PRUint32) PR_ntohl(PRUint32 n) { return ntohl(n); }
PR_IMPLEMENT(PRUint16) PR_htons(PRUint16 n) { return htons(n); }
PR_IMPLEMENT(PRUint32) PR_htonl(PRUint32 n) { return htonl(n); }
PR_IMPLEMENT(PRUint64) PR_ntohll(PRUint64 n)
{
#ifdef IS_BIG_ENDIAN
    return n;
#else
    PRUint64 tmp;
    PRUint32 hi, lo;
    LL_L2UI(lo, n);
    LL_SHR(tmp, n, 32);
    LL_L2UI(hi, tmp);
    hi = PR_ntohl(hi);
    lo = PR_ntohl(lo);
    LL_UI2L(n, lo);
    LL_SHL(n, n, 32);
    LL_UI2L(tmp, hi);
    LL_ADD(n, n, tmp);
    return n;
#endif
}  /* ntohll */

PR_IMPLEMENT(PRUint64) PR_htonll(PRUint64 n)
{
#ifdef IS_BIG_ENDIAN
    return n;
#else
    PRUint64 tmp;
    PRUint32 hi, lo;
    LL_L2UI(lo, n);
    LL_SHR(tmp, n, 32);
    LL_L2UI(hi, tmp);
    hi = htonl(hi);
    lo = htonl(lo);
    LL_UI2L(n, lo);
    LL_SHL(n, n, 32);
    LL_UI2L(tmp, hi);
    LL_ADD(n, n, tmp);
    return n;
#endif
}  /* htonll */


/*
 * Implementation of PR_GetAddrInfoByName and friends
 *
 * Compile-time options:
 *
 *  _PR_HAVE_GETADDRINFO  Define this macro if the target system provides
 *                        getaddrinfo. With this defined, NSPR will require
 *                        getaddrinfo at run time. If this if not defined,
 *                        then NSPR will attempt to dynamically resolve
 *                        getaddrinfo, falling back to PR_GetHostByName if
 *                        getaddrinfo does not exist on the target system.
 *
 * Since getaddrinfo is a relatively new system call on many systems,
 * we are forced to dynamically resolve it at run time in most cases.
 * The exception includes any system (such as Mac OS X) that is known to
 * provide getaddrinfo in all versions that NSPR cares to support.
 */

#ifdef MOZ_DNSSEC
#define GETADDRINFO(a,b,c,d) val_getaddrinfo(NULL, a, b, c, d, &val_status)
#define FREEADDRINFO val_freeaddrinfo
typedef struct addrinfo PRADDRINFO;
typedef struct val_addrinfo DNSSECPRADDRINFO;

#elif defined(_PR_HAVE_GETADDRINFO)

#if defined(_PR_INET6)

typedef struct addrinfo PRADDRINFO;
typedef struct addrinfo DNSSECPRADDRINFO;

#define GETADDRINFO getaddrinfo
#define FREEADDRINFO freeaddrinfo

#elif defined(_PR_INET6_PROBE)

typedef struct addrinfo PRADDRINFO;
typedef struct addrinfo DNSSECPRADDRINFO;

/* getaddrinfo/freeaddrinfo prototypes */ 
#if defined(WIN32)
#define FUNC_MODIFIER __stdcall
#else
#define FUNC_MODIFIER
#endif
typedef int (FUNC_MODIFIER * FN_GETADDRINFO)
    (const char *nodename,
     const char *servname,
     const PRADDRINFO *hints,
     PRADDRINFO **res);
typedef int (FUNC_MODIFIER * FN_FREEADDRINFO)
    (PRADDRINFO *ai);

/* global state */
static FN_GETADDRINFO   _pr_getaddrinfo   = NULL;
static FN_FREEADDRINFO  _pr_freeaddrinfo  = NULL;

#if defined(VMS)
#define GETADDRINFO_SYMBOL getenv("GETADDRINFO")
#define FREEADDRINFO_SYMBOL getenv("FREEADDRINFO")
#else
#define GETADDRINFO_SYMBOL "getaddrinfo"
#define FREEADDRINFO_SYMBOL "freeaddrinfo"
#endif

PRStatus
_pr_find_getaddrinfo(void)
{
    PRLibrary *lib;
#ifdef WIN32
    /*
     * On windows, we need to search ws2_32.dll or wship6.dll
     * (Microsoft IPv6 Technology Preview for Windows 2000) for
     * getaddrinfo and freeaddrinfo.  These libraries might not
     * be loaded yet.
     */
    const char *libname[] = { "ws2_32.dll", "wship6.dll" };
    int i;

    for (i = 0; i < sizeof(libname)/sizeof(libname[0]); i++) {
        lib = PR_LoadLibrary(libname[i]);
        if (!lib) {
            continue;
        }
        _pr_getaddrinfo = (FN_GETADDRINFO)
            PR_FindFunctionSymbol(lib, GETADDRINFO_SYMBOL);
        if (!_pr_getaddrinfo) {
            PR_UnloadLibrary(lib);
            continue;
        }
        _pr_freeaddrinfo = (FN_FREEADDRINFO)
            PR_FindFunctionSymbol(lib, FREEADDRINFO_SYMBOL);
        PR_ASSERT(_pr_freeaddrinfo);
        /* Keep the library loaded. */
        return PR_SUCCESS;
    }
    return PR_FAILURE;
#else
    /*
     * Resolve getaddrinfo by searching all loaded libraries.  Then
     * search library containing getaddrinfo for freeaddrinfo.
     */
    _pr_getaddrinfo = (FN_GETADDRINFO)
        PR_FindFunctionSymbolAndLibrary(GETADDRINFO_SYMBOL, &lib);
    if (!_pr_getaddrinfo) {
        return PR_FAILURE;
    }
    _pr_freeaddrinfo = (FN_FREEADDRINFO)
        PR_FindFunctionSymbol(lib, FREEADDRINFO_SYMBOL);
    PR_UnloadLibrary(lib);
    if (!_pr_freeaddrinfo) {
        return PR_FAILURE;
    }
    return PR_SUCCESS;
#endif
}

#endif /* _PR_INET6 */

#endif /* _PR_HAVE_GETADDRINFO */

/*
 * If getaddrinfo does not exist, then we will fall back on
 * PR_GetHostByName, which requires that we allocate a buffer for the 
 * PRHostEnt data structure and its members.
 */
typedef struct PRAddrInfoFB {
    char      buf[PR_NETDB_BUF_SIZE];
    PRHostEnt hostent;
    PRBool    has_cname;
} PRAddrInfoFB;

static PRAddrInfo *
pr_GetAddrInfoByNameFB(const char  *hostname,
                       PRUint16     af,
                       PRIntn       flags)
{
    PRStatus rv;
    PRAddrInfoFB *ai;
    DNSSECFUNDEBUG((stderr, "input=%s", hostname));
    /* fallback on PR_GetHostByName */
    ai = PR_NEW(PRAddrInfoFB);
    if (!ai) {
        PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
        return NULL;
    }
    DNSSECDEBUG((stderr, "DNSSECgethostbyname: %d %s\n", __LINE__, hostname));
    rv = PR_GetHostByNameExtended(hostname, ai->buf, sizeof ai->buf, &ai->hostent);
    if (rv == PR_FAILURE) {
        PR_Free(ai);
        DNSSECFUNRETURN(NULL);
    }
    ai->has_cname = !(flags & PR_AI_NOCANONNAME);

    DNSSECFUNRETURN((PRAddrInfo *) ai);
}

PR_IMPLEMENT(PRAddrInfo *) PR_GetAddrInfoByNameExtended(const char  *hostname,
                                                        PRUint16     af,
                                                        PRIntn       flags,
                                                        PRUint16     *security_flags)
{
#ifdef MOZ_DNSSEC
  val_status_t val_status;
#endif
    DNSSECFUNDEBUG((stderr, "input=%s\n", hostname));

    /* wipe the security flags */
    if (security_flags)
        *security_flags = PR_DNSSEC_NO_FLAGS;
    
    /* restrict input to supported values */
    if ((af != PR_AF_INET && af != PR_AF_UNSPEC) ||
        (flags & ~ PR_AI_NOCANONNAME) != PR_AI_ADDRCONFIG) {
        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
        DNSSECFUNRETURN(NULL);
    }

    if (!_pr_initialized) _PR_ImplicitInitialization();

#if !defined(_PR_HAVE_GETADDRINFO)
    DNSSECFUNRETURN(pr_GetAddrInfoByNameFB(hostname, af, flags));
#else
#if defined(_PR_INET6_PROBE)
    if (!_pr_ipv6_is_present) {
        DNSSECFUNRETURN(pr_GetAddrInfoByNameFB(hostname, af, flags));
    }
#endif
    {
        PRADDRINFO hints;
        DNSSECPRADDRINFO *res;
        PRStatus rv;

        /*
         * we assume a RFC 2553 compliant getaddrinfo.  this may at some
         * point need to be customized as platforms begin to adopt the
         * RFC 3493.
         */

        memset(&hints, 0, sizeof(hints));
        hints.ai_flags = (flags & PR_AI_NOCANONNAME) ? 0: AI_CANONNAME;
        hints.ai_family = (af == PR_AF_INET) ? AF_INET : AF_UNSPEC;

        /*
         * it is important to select a socket type in the hints, otherwise we
         * will get back repetitive entries: one for each socket type.  since
         * we do not expose ai_socktype through our API, it is okay to do this
         * here.  the application may still choose to create a socket of some
         * other type.
         */
        hints.ai_socktype = SOCK_STREAM;

        rv = GETADDRINFO(hostname, NULL, &hints, &res);
        if (rv == EAI_AGAIN) {
          /* temporary failure...  odd...  try again? */
          PR_Sleep(1000);
          DNSSECDEBUG((stderr, "DNSSECgetaddrinfo reted/trying again: %d %d\n", rv, (unsigned int) res));
          rv = GETADDRINFO(hostname, NULL, &hints, &res);
        }
        DNSSECDEBUG((stderr, "DNSSECgetaddrinfo returned: %d\n", (unsigned int) res));

#ifdef MOZ_DNSSEC
        if (dnssec_check_policy(val_status, global_policy) != DNSSEC_SUCCESS) {
          /* DNSsec validation failed */
          PR_SetErrorText(0, "Host DNSsec validation failed");
          PR_SetError(PR_DNSSEC_VALIDATION_ERROR, 0);
          DNSSECDEBUG((stderr, "DNSSECgetaddrinfo: returning failure line:%d %s => val_status:%d\n", __LINE__, hostname, val_status));
          if(res)
              val_freeaddrinfo(res);
          DNSSECFUNRETURN(NULL);
        }

        if (!res && val_status == VAL_VALIDATED_ANSWER) {
          /* DNSSEC has proven that the record does not exist; we
             return a different error message to show that the lookup
             succeeded and there is officially no results */
          PR_SetErrorText(0, "Address does not exist");
          PR_SetError(PR_DNSSEC_DNE_ERROR, 0);
          DNSSECDEBUG((stderr, "DNSSECgetaddrinfo: returning DNE failure:%d %s => val_status:%d\n", __LINE__, hostname, val_status));
          DNSSECFUNRETURN(NULL);
        }

        /* set the security flags to how the results were achieved */
        if (security_flags) {
          if (val_isvalidated(val_status))
              *security_flags |= PR_DNSSEC_IS_VALIDATED;
          
          if (val_istrusted(val_status))
              *security_flags |= PR_DNSSEC_IS_TRUSTED;
        }
#endif

        if (rv == 0) {
          DNSSECFUNRETURN((PRAddrInfo *) res);
        }

        DNSSECDEBUG((stderr, "DNSSECgetaddrinfo failed: %d\n", rv));
        PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, rv);
    }
    DNSSECFUNRETURN(NULL);
#endif
}

PR_IMPLEMENT(PRAddrInfo *) PR_GetAddrInfoByName(const char  *hostname,
                                                PRUint16     af,
                                                PRIntn       flags)
{
  struct PRAddrInfo *result;
  DNSSECFUNDEBUG((stderr, "input=%s\n", hostname));
  result = PR_GetAddrInfoByNameExtended(hostname, af, flags, NULL);
  simplify_return_value();
  DNSSECFUNRETURN(result);
}


PR_IMPLEMENT(void) PR_FreeAddrInfo(PRAddrInfo *ai)
{
#if defined(MOZ_DNSSEC)
        FREEADDRINFO((DNSSECPRADDRINFO *) ai);
#elif defined(_PR_HAVE_GETADDRINFO)
#if defined(_PR_INET6_PROBE)
    if (!_pr_ipv6_is_present)
        PR_Free((PRAddrInfoFB *) ai);
    else
#endif
        FREEADDRINFO((PRADDRINFO *) ai);
#else
    PR_Free((PRAddrInfoFB *) ai);
#endif
}

PR_IMPLEMENT(void *) PR_EnumerateAddrInfo(void             *iterPtr,
                                          const PRAddrInfo *base,
                                          PRUint16          port,
                                          PRNetAddr        *result)
{
#if defined(_PR_HAVE_GETADDRINFO) || defined(MOZ_DNSSEC)
    DNSSECPRADDRINFO *ai;
#if defined(_PR_INET6_PROBE) && !defined(MOZ_DNSSEC)
    if (!_pr_ipv6_is_present) {
        /* using PRAddrInfoFB */
        PRIntn iter = (PRIntn)(PRPtrdiff) iterPtr;
        iter = PR_EnumerateHostEnt(iter, &((PRAddrInfoFB *) base)->hostent, port, result);
        if (iter < 0)
            iter = 0;
        return (void *)(PRPtrdiff) iter;
    }
#endif

    if (iterPtr)
        ai = ((DNSSECPRADDRINFO *) iterPtr)->ai_next;
    else
        ai = (DNSSECPRADDRINFO *) base;

    if (ai) {
        /* copy sockaddr to PRNetAddr */
        memcpy(result, ai->ai_addr, ai->ai_addrlen);
        result->raw.family = ai->ai_addr->sa_family;
        if (ai->ai_addrlen < sizeof(PRNetAddr))
            memset(((char*)result)+ai->ai_addrlen, 0, sizeof(PRNetAddr) - ai->ai_addrlen);

        if (result->raw.family == PR_AF_INET)
            result->inet.port = htons(port);
        else
            result->ipv6.port = htons(port);
    }

    return ai;
#else
    /* using PRAddrInfoFB */
    PRIntn iter = (PRIntn) iterPtr;
    iter = PR_EnumerateHostEnt(iter, &((PRAddrInfoFB *) base)->hostent, port, result);
    if (iter < 0)
        iter = 0;
    return (void *) iter;
#endif
}

PR_IMPLEMENT(const char *) PR_GetCanonNameFromAddrInfo(const PRAddrInfo *ai)
{
#if defined(_PR_HAVE_GETADDRINFO)
#if defined(_PR_INET6_PROBE)
    if (!_pr_ipv6_is_present) {
        const PRAddrInfoFB *fb = (const PRAddrInfoFB *) ai;
        return fb->has_cname ? fb->hostent.h_name : NULL;
    } 
#endif
    return ((const PRADDRINFO *) ai)->ai_canonname;
#else
    const PRAddrInfoFB *fb = (const PRAddrInfoFB *) ai;
    return fb->has_cname ? fb->hostent.h_name : NULL;
#endif
}