Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2549 insertions, 0 deletions

diff --git a/nsprpub/pr/src/misc/prnetdb.c b/nsprpub/pr/src/misc/prnetdb.c
new file mode 100644
index 0000000000..7decd96751
--- /dev/null
+++ b/nsprpub/pr/src/misc/prnetdb.c
@@ -0,0 +1,2549 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "primpl.h"
+
+#include <string.h>
+
+#if defined(LINUX)
+#include <sys/un.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.
+ * -  _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.
+ */
+#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 three flavors.
+ * Some return a pointer to struct protoent, others return
+ * an int, and glibc's flavor takes five arguments.
+ */
+
+#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(AIX4_3_PLUS) || (defined(AIX) && defined(_THREAD_SAFE)) \
+    || (defined(HPUX10_10) && defined(_REENTRANT)) \
+        || (defined(HPUX10_20) && defined(_REENTRANT)) \
+        || defined(OPENBSD)
+#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
+
+/* BeOS has glibc but not the glibc-style getprotobyxxx_r functions. */
+#if (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)
+extern PRBool _pr_ipv6_is_present(void);
+#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))
+
+/*
+ * 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) */
+
+/*
+ * #################################################################
+ * 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 */
+
+PR_IMPLEMENT(PRStatus) PR_GetHostByName(
+    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();
+    }
+
+#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
+
+    LOCK_DNS();
+
+    h = GETHOSTBYNAME(name);
+
+    if (NULL == h)
+    {
+        PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, _MD_GETHOST_ERRNO());
+    }
+    else
+    {
+        _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
+    return rv;
+}
+
+#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;
+#define GETIPNODEBYNAME "getipnodebyname"
+#define GETIPNODEBYADDR "getipnodebyaddr"
+#define FREEHOSTENT     "freehostent"
+
+    _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_GetIPNodeByName(
+    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
+
+    if (!_pr_initialized) {
+        _PR_ImplicitInitialization();
+    }
+
+    if (af != PR_AF_INET && af != PR_AF_INET6) {
+        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
+        return 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);
+            return rv;
+        }
+    }
+#endif
+
+    /* 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())
+#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())
+    {
+#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();
+    h = GETHOSTBYNAME(name);
+#endif /* _PR_INET6 */
+
+    if (NULL == h)
+    {
+#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_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_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()) {
+        UNLOCK_DNS();
+    }
+#endif
+#else /* _PR_INET6 */
+    UNLOCK_DNS();
+#endif /* _PR_INET6 */
+
+#if defined(_PR_HAVE_GETHOST_R)
+    if (tmpbuf != localbuf) {
+        PR_Free(tmpbuf);
+    }
+#endif
+
+    return rv;
+}
+
+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
+
+    if (!_pr_initialized) {
+        _PR_ImplicitInitialization();
+    }
+
+    if (hostaddr->raw.family == PR_AF_INET6)
+    {
+#if defined(_PR_INET6_PROBE)
+        af = _pr_ipv6_is_present() ? AF_INET6 : 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())
+    {
+#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();
+    h = GETHOSTBYADDR(addr, addrlen, af);
+#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_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_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()) {
+        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
+
+    return 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.
+ */
+
+#if defined(ANDROID)
+/* Android's Bionic libc system includes prototypes for these in netdb.h,
+ * but doesn't actually include implementations.  It uses the 5-arg form,
+ * so these functions end up not matching the prototype.  So just rename
+ * them if not found.
+ */
+#define getprotobyname_r _pr_getprotobyname_r
+#define getprotobynumber_r _pr_getprotobynumber_r
+#endif
+
+static struct protoent *getprotobyname_r(const char* name)
+{
+    return getprotobyname(name);
+} /* 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_MIN_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_MIN_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)
+    else if (AF_UNIX == addr->raw.family)
+    {
+#if defined(LINUX)
+        if (addr->local.path[0] == 0)
+            /* abstract socket address is supported on Linux only */
+            addrsize = strnlen(addr->local.path + 1,
+                               sizeof(addr->local.path)) +
+                       offsetof(struct sockaddr_un, sun_path) + 1;
+        else
+#endif
+            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));
+    }
+    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;
+            }
+            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;
+            }
+            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;
+            }
+            if (val == PR_IpAddrLoopback
+                && addr->inet.ip == htonl(INADDR_LOOPBACK)) {
+                return PR_TRUE;
+            }
+        }
+    }
+    return PR_FALSE;
+}
+
+extern int pr_inet_aton(const char *cp, PRUint32 *addr);
+
+#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
+
+#ifndef _PR_HAVE_INET_NTOP
+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 */
+
+/*
+ * 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
+    PRUint32 hi, lo;
+    lo = (PRUint32)n;
+    hi = (PRUint32)(n >> 32);
+    hi = PR_ntohl(hi);
+    lo = PR_ntohl(lo);
+    return ((PRUint64)lo << 32) + (PRUint64)hi;
+#endif
+}  /* ntohll */
+
+PR_IMPLEMENT(PRUint64) PR_htonll(PRUint64 n)
+{
+#ifdef IS_BIG_ENDIAN
+    return n;
+#else
+    PRUint32 hi, lo;
+    lo = (PRUint32)n;
+    hi = (PRUint32)(n >> 32);
+    hi = htonl(hi);
+    lo = htonl(lo);
+    return ((PRUint64)lo << 32) + (PRUint64)hi;
+#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.
+ */
+
+#if defined(_PR_HAVE_GETADDRINFO)
+
+#if defined(_PR_INET6)
+
+typedef struct addrinfo PRADDRINFO;
+#define GETADDRINFO getaddrinfo
+#define FREEADDRINFO freeaddrinfo
+#define GETNAMEINFO getnameinfo
+
+#elif defined(_PR_INET6_PROBE)
+
+typedef struct addrinfo PRADDRINFO;
+
+/* getaddrinfo/freeaddrinfo/getnameinfo 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);
+typedef int (FUNC_MODIFIER * FN_GETNAMEINFO)
+(const struct sockaddr *addr, int addrlen,
+ char *host, int hostlen,
+ char *serv, int servlen, int flags);
+
+/* global state */
+static FN_GETADDRINFO   _pr_getaddrinfo   = NULL;
+static FN_FREEADDRINFO  _pr_freeaddrinfo  = NULL;
+static FN_GETNAMEINFO   _pr_getnameinfo   = NULL;
+
+#define GETADDRINFO_SYMBOL "getaddrinfo"
+#define FREEADDRINFO_SYMBOL "freeaddrinfo"
+#define GETNAMEINFO_SYMBOL "getnameinfo"
+
+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_getnameinfo = (FN_GETNAMEINFO)
+                          PR_FindFunctionSymbol(lib, GETNAMEINFO_SYMBOL);
+        if (!_pr_freeaddrinfo || !_pr_getnameinfo) {
+            PR_UnloadLibrary(lib);
+            continue;
+        }
+        /* 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_getnameinfo = (FN_GETNAMEINFO)
+                      PR_FindFunctionSymbol(lib, GETNAMEINFO_SYMBOL);
+    PR_UnloadLibrary(lib);
+    if (!_pr_freeaddrinfo || !_pr_getnameinfo) {
+        return PR_FAILURE;
+    }
+    return PR_SUCCESS;
+#endif
+}
+
+#define GETADDRINFO (*_pr_getaddrinfo)
+#define FREEADDRINFO (*_pr_freeaddrinfo)
+#define GETNAMEINFO (*_pr_getnameinfo)
+
+#endif /* _PR_INET6 */
+
+#endif /* _PR_HAVE_GETADDRINFO */
+
+#if !defined(_PR_HAVE_GETADDRINFO) || defined(_PR_INET6_PROBE)
+/*
+ * 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;
+    /* fallback on PR_GetHostByName */
+    ai = PR_NEW(PRAddrInfoFB);
+    if (!ai) {
+        PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
+        return NULL;
+    }
+    rv = PR_GetHostByName(hostname, ai->buf, sizeof ai->buf, &ai->hostent);
+    if (rv == PR_FAILURE) {
+        PR_Free(ai);
+        return NULL;
+    }
+    ai->has_cname = !(flags & PR_AI_NOCANONNAME);
+
+    return (PRAddrInfo *) ai;
+}
+#endif /* !_PR_HAVE_GETADDRINFO || _PR_INET6_PROBE */
+
+PR_IMPLEMENT(PRAddrInfo *) PR_GetAddrInfoByName(const char  *hostname,
+        PRUint16     af,
+        PRIntn       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);
+        return NULL;
+    }
+
+    if (!_pr_initialized) {
+        _PR_ImplicitInitialization();
+    }
+
+#if !defined(_PR_HAVE_GETADDRINFO)
+    return pr_GetAddrInfoByNameFB(hostname, af, flags);
+#else
+#if defined(_PR_INET6_PROBE)
+    if (!_pr_ipv6_is_present()) {
+        return pr_GetAddrInfoByNameFB(hostname, af, flags);
+    }
+#endif
+    {
+        PRADDRINFO *res, hints;
+        int 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));
+        if (!(flags & PR_AI_NOCANONNAME)) {
+            hints.ai_flags |= AI_CANONNAME;
+        }
+#ifdef AI_ADDRCONFIG
+        /*
+         * Propagate AI_ADDRCONFIG to the GETADDRINFO call if PR_AI_ADDRCONFIG
+         * is set.
+         *
+         * Need a workaround for loopback host addresses:
+         * The problem is that in glibc and Windows, AI_ADDRCONFIG applies the
+         * existence of an outgoing network interface to IP addresses of the
+         * loopback interface, due to a strict interpretation of the
+         * specification.  For example, if a computer does not have any
+         * outgoing IPv6 network interface, but its loopback network interface
+         * supports IPv6, a getaddrinfo call on "localhost" with AI_ADDRCONFIG
+         * won't return the IPv6 loopback address "::1", because getaddrinfo
+         * thinks the computer cannot connect to any IPv6 destination,
+         * ignoring the remote vs. local/loopback distinction.
+         */
+        if ((flags & PR_AI_ADDRCONFIG) &&
+            strcmp(hostname, "localhost") != 0 &&
+            strcmp(hostname, "localhost.localdomain") != 0 &&
+            strcmp(hostname, "localhost6") != 0 &&
+            strcmp(hostname, "localhost6.localdomain6") != 0) {
+            hints.ai_flags |= AI_ADDRCONFIG;
+        }
+#endif
+        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);
+#ifdef AI_ADDRCONFIG
+        if (rv == EAI_BADFLAGS && (hints.ai_flags & AI_ADDRCONFIG)) {
+            hints.ai_flags &= ~AI_ADDRCONFIG;
+            rv = GETADDRINFO(hostname, NULL, &hints, &res);
+        }
+#endif
+        if (rv == 0) {
+            return (PRAddrInfo *) res;
+        }
+
+        PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, rv);
+    }
+    return NULL;
+#endif
+}
+
+PR_IMPLEMENT(PRStatus)
+PR_GetPrefLoopbackAddrInfo(PRNetAddr *result,
+                           PRUint16 port)
+{
+    char          tmpBuf[ 40 ];
+    const int     tmpBufSize = sizeof( tmpBuf );
+
+    if (!result) {
+        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
+        return PR_FAILURE;
+    }
+
+    if (!_pr_initialized) _PR_ImplicitInitialization();
+
+    PR_snprintf(tmpBuf, tmpBufSize, "%u", port );
+
+#if !defined(_PR_HAVE_GETADDRINFO) || !defined(AI_PASSIVE)
+    PR_SetError(PR_NOT_IMPLEMENTED_ERROR, 0);
+    return PR_FAILURE;
+#else
+
+    PRADDRINFO *res, hints;
+    PRStatus rv;
+
+    memset(&hints, 0, sizeof(hints));
+
+    rv = GETADDRINFO(NULL, tmpBuf, &hints, &res);
+    if (rv == 0) {
+        PRBool result_still_empty = PR_TRUE;
+        PRADDRINFO *ai = res;
+        do {
+            PRNetAddr aNetAddr;
+
+            while (ai && ai->ai_addrlen > sizeof(PRNetAddr))
+                ai = ai->ai_next;
+
+            if (ai) {
+                /* copy sockaddr to PRNetAddr */
+                memcpy(&aNetAddr, ai->ai_addr, ai->ai_addrlen);
+                aNetAddr.raw.family = ai->ai_addr->sa_family;
+#ifdef _PR_INET6
+                if (AF_INET6 == aNetAddr.raw.family)
+                    aNetAddr.raw.family = PR_AF_INET6;
+#endif
+                if (ai->ai_addrlen < sizeof(PRNetAddr))
+                    memset(((char*)result)+ai->ai_addrlen, 0,
+                           sizeof(PRNetAddr) - ai->ai_addrlen);
+            }
+
+            /* If we obtain more than one result, prefer IPv6. */
+            if (result_still_empty || aNetAddr.raw.family == PR_AF_INET6) {
+                memcpy(result, &aNetAddr, sizeof(PRNetAddr));
+            }
+            result_still_empty = PR_FALSE;
+            ai = ai->ai_next;
+        }
+        while (ai);
+
+        FREEADDRINFO(res);
+        return PR_SUCCESS;
+    }
+
+    PR_SetError(PR_DIRECTORY_LOOKUP_ERROR, rv);
+    return PR_FAILURE;
+#endif
+}
+
+PR_IMPLEMENT(void) PR_FreeAddrInfo(PRAddrInfo *ai)
+{
+#if 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)
+    PRADDRINFO *ai;
+#if defined(_PR_INET6_PROBE)
+    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 = ((PRADDRINFO *) iterPtr)->ai_next;
+    }
+    else {
+        ai = (PRADDRINFO *) base;
+    }
+
+    while (ai && ai->ai_addrlen > sizeof(PRNetAddr)) {
+        ai = ai->ai_next;
+    }
+
+    if (ai) {
+        /* copy sockaddr to PRNetAddr */
+        memcpy(result, ai->ai_addr, ai->ai_addrlen);
+        result->raw.family = ai->ai_addr->sa_family;
+#ifdef _PR_INET6
+        if (AF_INET6 == result->raw.family) {
+            result->raw.family = PR_AF_INET6;
+        }
+#endif
+        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
+}
+
+#if defined(_PR_HAVE_GETADDRINFO)
+static PRStatus pr_StringToNetAddrGAI(const char *string, PRNetAddr *addr)
+{
+    PRADDRINFO *res, hints;
+    int rv;  /* 0 for success, or the error code EAI_xxx */
+    PRNetAddr laddr;
+    PRStatus status = PR_SUCCESS;
+
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_flags = AI_NUMERICHOST;
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = SOCK_STREAM;
+
+    rv = GETADDRINFO(string, NULL, &hints, &res);
+    if (rv != 0)
+    {
+        PR_SetError(PR_INVALID_ARGUMENT_ERROR, rv);
+        return PR_FAILURE;
+    }
+
+    /* pick up the first addr */
+    memcpy(&laddr, res->ai_addr, res->ai_addrlen);
+    if (AF_INET6 == res->ai_addr->sa_family)
+    {
+        addr->ipv6.family = PR_AF_INET6;
+        addr->ipv6.ip = laddr.ipv6.ip;
+        addr->ipv6.scope_id = laddr.ipv6.scope_id;
+    }
+    else if (AF_INET == res->ai_addr->sa_family)
+    {
+        addr->inet.family = PR_AF_INET;
+        addr->inet.ip = laddr.inet.ip;
+    }
+    else
+    {
+        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
+        status = PR_FAILURE;
+    }
+
+    FREEADDRINFO(res);
+    return status;
+}
+#endif  /* _PR_HAVE_GETADDRINFO */
+
+static PRStatus pr_StringToNetAddrFB(const char *string, PRNetAddr *addr)
+{
+    PRIntn rv;
+
+    rv = pr_inet_aton(string, &addr->inet.ip);
+    if (1 == rv)
+    {
+        addr->raw.family = AF_INET;
+        return PR_SUCCESS;
+    }
+
+    PR_ASSERT(0 == rv);
+    /* clean up after the failed call */
+    memset(&addr->inet.ip, 0, sizeof(addr->inet.ip));
+
+    rv = StringToV6Addr(string, &addr->ipv6.ip);
+    if (1 == rv)
+    {
+        addr->raw.family = PR_AF_INET6;
+        return PR_SUCCESS;
+    }
+
+    PR_ASSERT(0 == rv);
+    PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
+    return PR_FAILURE;
+}
+
+PR_IMPLEMENT(PRStatus) PR_StringToNetAddr(const char *string, PRNetAddr *addr)
+{
+    if (!_pr_initialized) {
+        _PR_ImplicitInitialization();
+    }
+
+    if (!addr || !string || !*string)
+    {
+        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
+        return PR_FAILURE;
+    }
+
+#if !defined(_PR_HAVE_GETADDRINFO)
+    return pr_StringToNetAddrFB(string, addr);
+#else
+    /*
+     * getaddrinfo with AI_NUMERICHOST is much slower than pr_inet_aton on some
+     * platforms, such as Mac OS X (bug 404399), Linux glibc 2.10 (bug 344809),
+     * and most likely others. So we only use it to convert literal IP addresses
+     * that contain IPv6 scope IDs, which pr_inet_aton cannot convert.
+     */
+    if (!strchr(string, '%')) {
+        return pr_StringToNetAddrFB(string, addr);
+    }
+
+#if defined(_PR_INET6_PROBE)
+    if (!_pr_ipv6_is_present()) {
+        return pr_StringToNetAddrFB(string, addr);
+    }
+#endif
+
+    return pr_StringToNetAddrGAI(string, addr);
+#endif
+}
+
+#if defined(_PR_HAVE_GETADDRINFO)
+static PRStatus pr_NetAddrToStringGNI(
+    const PRNetAddr *addr, char *string, PRUint32 size)
+{
+    int addrlen;
+    const PRNetAddr *addrp = addr;
+#if defined(_PR_HAVE_SOCKADDR_LEN) || defined(_PR_INET6)
+    PRUint16 md_af = addr->raw.family;
+    PRNetAddr addrcopy;
+#endif
+    int rv;  /* 0 for success, or the error code EAI_xxx */
+
+#ifdef _PR_INET6
+    if (addr->raw.family == PR_AF_INET6)
+    {
+        md_af = AF_INET6;
+#ifndef _PR_HAVE_SOCKADDR_LEN
+        addrcopy = *addr;
+        addrcopy.raw.family = md_af;
+        addrp = &addrcopy;
+#endif
+    }
+#endif
+
+    addrlen = PR_NETADDR_SIZE(addr);
+#ifdef _PR_HAVE_SOCKADDR_LEN
+    addrcopy = *addr;
+    ((struct sockaddr*)&addrcopy)->sa_len = addrlen;
+    ((struct sockaddr*)&addrcopy)->sa_family = md_af;
+    addrp = &addrcopy;
+#endif
+    rv = GETNAMEINFO((const struct sockaddr *)addrp, addrlen,
+                     string, size, NULL, 0, NI_NUMERICHOST);
+    if (rv != 0)
+    {
+        PR_SetError(PR_INVALID_ARGUMENT_ERROR, rv);
+        return PR_FAILURE;
+    }
+    return PR_SUCCESS;
+}
+#endif  /* _PR_HAVE_GETADDRINFO */
+
+#if !defined(_PR_HAVE_GETADDRINFO) || defined(_PR_INET6_PROBE)
+static PRStatus pr_NetAddrToStringFB(
+    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_NetAddrToStringFB */
+#endif  /* !_PR_HAVE_GETADDRINFO || _PR_INET6_PROBE */
+
+PR_IMPLEMENT(PRStatus) PR_NetAddrToString(
+    const PRNetAddr *addr, char *string, PRUint32 size)
+{
+    if (!_pr_initialized) {
+        _PR_ImplicitInitialization();
+    }
+
+#if !defined(_PR_HAVE_GETADDRINFO)
+    return pr_NetAddrToStringFB(addr, string, size);
+#else
+#if defined(_PR_INET6_PROBE)
+    if (!_pr_ipv6_is_present()) {
+        return pr_NetAddrToStringFB(addr, string, size);
+    }
+#endif
+    return pr_NetAddrToStringGNI(addr, string, size);
+#endif
+}  /* PR_NetAddrToString */