Adding upstream version 1:9.11.5.P4+dfsg.upstream/1%9.11.5.P4+dfsgupstream

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

1 files changed, 1160 insertions, 0 deletions

diff --git a/lib/lwres/getipnode.c b/lib/lwres/getipnode.c
new file mode 100644
index 0000000..f0c0ae6
--- /dev/null
+++ b/lib/lwres/getipnode.c
@@ -0,0 +1,1160 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * 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/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/* $Id: getipnode.c,v 1.47 2009/09/01 23:47:45 tbox Exp $ */
+
+/*! \file */
+
+/**
+ *    These functions perform thread safe, protocol independent
+ *    nodename-to-address and address-to-nodename translation as defined in
+ *    RFC2553.  This use a struct hostent which is defined in namedb.h:
+ *
+ * \code
+ * struct  hostent {
+ *         char    *h_name;        // official name of host
+ *         char    **h_aliases;    // alias list
+ *         int     h_addrtype;     // host address type
+ *         int     h_length;       // length of address
+ *         char    **h_addr_list;  // list of addresses from name server
+ * };
+ * #define h_addr  h_addr_list[0]  // address, for backward compatibility
+ * \endcode
+ *
+ *    The members of this structure are:
+ *
+ * \li   h_name:
+ *           The official (canonical) name of the host.
+ *
+ * \li   h_aliases:
+ *           A NULL-terminated array of alternate names (nicknames) for the
+ *           host.
+ *
+ * \li   h_addrtype:
+ *           The type of address being returned - usually PF_INET or
+ *           PF_INET6.
+ *
+ * \li   h_length:
+ *           The length of the address in bytes.
+ *
+ * \li   h_addr_list:
+ *           A NULL terminated array of network addresses for the host. Host
+ *           addresses are returned in network byte order.
+ *
+ *    lwres_getipnodebyname() looks up addresses of protocol family af for
+ *    the hostname name. The flags parameter contains ORed flag bits to
+ *    specify the types of addresses that are searched for, and the types of
+ *    addresses that are returned. The flag bits are:
+ *
+ * \li   #AI_V4MAPPED:
+ *           This is used with an af of #AF_INET6, and causes IPv4 addresses
+ *           to be returned as IPv4-mapped IPv6 addresses.
+ *
+ * \li   #AI_ALL:
+ *           This is used with an af of #AF_INET6, and causes all known
+ *           addresses (IPv6 and IPv4) to be returned. If #AI_V4MAPPED is
+ *           also set, the IPv4 addresses are return as mapped IPv6
+ *           addresses.
+ *
+ * \li   #AI_ADDRCONFIG:
+ *           Only return an IPv6 or IPv4 address if here is an active
+ *           network interface of that type. This is not currently
+ *           implemented in the BIND 9 lightweight resolver, and the flag is
+ *           ignored.
+ *
+ * \li   #AI_DEFAULT:
+ *           This default sets the #AI_V4MAPPED and #AI_ADDRCONFIG flag bits.
+ *
+ *    lwres_getipnodebyaddr() performs a reverse lookup of address src which
+ *    is len bytes long. af denotes the protocol family, typically PF_INET
+ *    or PF_INET6.
+ *
+ *    lwres_freehostent() releases all the memory associated with the struct
+ *    hostent pointer. Any memory allocated for the h_name, h_addr_list
+ *    and h_aliases is freed, as is the memory for the hostent structure
+ *    itself.
+ *
+ * \section getipnode_return Return Values
+ *
+ *    If an error occurs, lwres_getipnodebyname() and
+ *    lwres_getipnodebyaddr() set *error_num to an appropriate error code
+ *    and the function returns a NULL pointer. The error codes and their
+ *    meanings are defined in \link netdb.h <lwres/netdb.h>\endlink:
+ *
+ * \li   #HOST_NOT_FOUND:
+ *           No such host is known.
+ *
+ * \li   #NO_ADDRESS:
+ *           The server recognised the request and the name but no address
+ *           is available. Another type of request to the name server for
+ *           the domain might return an answer.
+ *
+ * \li   #TRY_AGAIN:
+ *           A temporary and possibly transient error occurred, such as a
+ *           failure of a server to respond. The request may succeed if
+ *           retried.
+ *
+ * \li   #NO_RECOVERY:
+ *           An unexpected failure occurred, and retrying the request is
+ *           pointless.
+ *
+ *    lwres_hstrerror() translates these error codes to suitable error
+ *    messages.
+ *
+ * \section getipnode_see See Also
+ *
+ * getaddrinfo.c, gethost.c, getnameinfo.c, herror.c, RFC2553
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <lwres/lwres.h>
+#include <lwres/net.h>
+#include <lwres/netdb.h>	/* XXX #include <netdb.h> */
+
+#include "assert_p.h"
+
+#ifndef INADDRSZ
+#define INADDRSZ 4
+#endif
+#ifndef IN6ADDRSZ
+#define IN6ADDRSZ 16
+#endif
+
+#ifdef LWRES_PLATFORM_NEEDIN6ADDRANY
+LIBLWRES_EXTERNAL_DATA const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
+#endif
+
+#ifndef IN6_IS_ADDR_V4COMPAT
+static const unsigned char in6addr_compat[12] = {
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+#define IN6_IS_ADDR_V4COMPAT(x) (!memcmp((x)->s6_addr, in6addr_compat, 12) && \
+				 ((x)->s6_addr[12] != 0 || \
+				  (x)->s6_addr[13] != 0 || \
+				  (x)->s6_addr[14] != 0 || \
+				   ((x)->s6_addr[15] != 0 && \
+				    (x)->s6_addr[15] != 1)))
+#endif
+#ifndef IN6_IS_ADDR_V4MAPPED
+#define IN6_IS_ADDR_V4MAPPED(x) (!memcmp((x)->s6_addr, in6addr_mapped, 12))
+#endif
+
+static const unsigned char in6addr_mapped[12] = {
+	0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0xff, 0xff
+};
+
+/***
+ ***	Forward declarations.
+ ***/
+
+static int
+scan_interfaces(int *, int *);
+
+static struct hostent *
+copyandmerge(struct hostent *, struct hostent *, int, int *);
+
+static struct hostent *
+hostfromaddr(lwres_gnbaresponse_t *addr, int af, const void *src);
+
+static struct hostent *
+hostfromname(lwres_gabnresponse_t *name, int af);
+
+/***
+ ***	Public functions.
+ ***/
+
+/*!
+ *	AI_V4MAPPED + AF_INET6
+ *	If no IPv6 address then a query for IPv4 and map returned values.
+ *
+ *	AI_ALL + AI_V4MAPPED + AF_INET6
+ *	Return IPv6 and IPv4 mapped.
+ *
+ *	AI_ADDRCONFIG
+ *	Only return IPv6 / IPv4 address if there is an interface of that
+ *	type active.
+ */
+
+struct hostent *
+lwres_getipnodebyname(const char *name, int af, int flags, int *error_num) {
+	int have_v4 = 1, have_v6 = 1;
+	struct in_addr in4;
+	struct in6_addr in6;
+	struct hostent he, *he1 = NULL, *he2 = NULL, *he3 = NULL;
+	int v4 = 0, v6 = 0;
+	int tmp_err = 0;
+	lwres_context_t *lwrctx = NULL;
+	lwres_gabnresponse_t *by = NULL;
+	int n;
+
+	/*
+	 * If we care about active interfaces then check.
+	 */
+	if ((flags & AI_ADDRCONFIG) != 0)
+		if (scan_interfaces(&have_v4, &have_v6) == -1) {
+			*error_num = NO_RECOVERY;
+			return (NULL);
+		}
+
+	/* Check for literal address. */
+	if ((v4 = lwres_net_pton(AF_INET, name, &in4)) != 1)
+		v6 = lwres_net_pton(AF_INET6, name, &in6);
+
+	/*
+	 * Impossible combination?
+	 */
+	if ((af == AF_INET6 && (flags & AI_V4MAPPED) == 0 && v4 == 1) ||
+	    (af == AF_INET && v6 == 1) ||
+	    (have_v4 == 0 && v4 == 1) ||
+	    (have_v6 == 0 && v6 == 1) ||
+	    (have_v4 == 0 && af == AF_INET) ||
+	    (have_v6 == 0 && af == AF_INET6 &&
+	     (((flags & AI_V4MAPPED) != 0 && have_v4) ||
+	      (flags & AI_V4MAPPED) == 0))) {
+		*error_num = HOST_NOT_FOUND;
+		return (NULL);
+	}
+
+	/*
+	 * Literal address?
+	 */
+	if (v4 == 1 || v6 == 1) {
+		char *addr_list[2];
+		char *aliases[1];
+		char mappedname[sizeof("::ffff:123.123.123.123")];
+		union {
+			const char *const_name;
+			char *deconst_name;
+		} u;
+
+		u.const_name = name;
+		if (v4 == 1 && af == AF_INET6) {
+			strcpy(mappedname, "::ffff:");
+			lwres_net_ntop(AF_INET, (char *)&in4,
+				       mappedname + sizeof("::ffff:") - 1,
+				       sizeof(mappedname) - sizeof("::ffff:")
+				       + 1);
+			he.h_name = mappedname;
+		} else
+			he.h_name = u.deconst_name;
+		he.h_addr_list = addr_list;
+		he.h_addr_list[0] = (v4 == 1) ? (char *)&in4 : (char *)&in6;
+		he.h_addr_list[1] = NULL;
+		he.h_aliases = aliases;
+		he.h_aliases[0] = NULL;
+		he.h_length = (v4 == 1) ? INADDRSZ : IN6ADDRSZ;
+		he.h_addrtype = (v4 == 1) ? AF_INET : AF_INET6;
+		return (copyandmerge(&he, NULL, af, error_num));
+	}
+
+	n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
+	if (n != 0) {
+		*error_num = NO_RECOVERY;
+		goto cleanup;
+	}
+	(void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
+	tmp_err = NO_RECOVERY;
+	if (have_v6 && af == AF_INET6) {
+		n = lwres_getaddrsbyname(lwrctx, name, LWRES_ADDRTYPE_V6, &by);
+		if (n == 0) {
+			he1 = hostfromname(by, AF_INET6);
+			lwres_gabnresponse_free(lwrctx, &by);
+			if (he1 == NULL) {
+				*error_num = NO_RECOVERY;
+				goto cleanup;
+			}
+		} else {
+			if (n == LWRES_R_NOTFOUND)
+				tmp_err = HOST_NOT_FOUND;
+			else {
+				*error_num = NO_RECOVERY;
+				goto cleanup;
+			}
+		}
+	}
+
+	if (have_v4 &&
+	    ((af == AF_INET) ||
+	     (af == AF_INET6 && (flags & AI_V4MAPPED) != 0 &&
+	      (he1 == NULL || (flags & AI_ALL) != 0)))) {
+		n = lwres_getaddrsbyname(lwrctx, name, LWRES_ADDRTYPE_V4, &by);
+		if (n == 0) {
+			he2 = hostfromname(by, AF_INET);
+			lwres_gabnresponse_free(lwrctx, &by);
+			if (he2 == NULL) {
+				*error_num = NO_RECOVERY;
+				goto cleanup;
+			}
+		} else if (he1 == NULL) {
+			if (n == LWRES_R_NOTFOUND)
+				*error_num = HOST_NOT_FOUND;
+			else
+				*error_num = NO_RECOVERY;
+			goto cleanup;
+		}
+	} else
+		*error_num = tmp_err;
+
+	he3 = copyandmerge(he1, he2, af, error_num);
+
+ cleanup:
+	if (he1 != NULL)
+		lwres_freehostent(he1);
+	if (he2 != NULL)
+		lwres_freehostent(he2);
+	if (lwrctx != NULL) {
+		lwres_conf_clear(lwrctx);
+		lwres_context_destroy(&lwrctx);
+	}
+	return (he3);
+}
+
+/*% performs a reverse lookup of address src which is len bytes long. af denotes the protocol family, typically #PF_INET or PF_INET6. */
+struct hostent *
+lwres_getipnodebyaddr(const void *src, size_t len, int af, int *error_num) {
+	struct hostent *he1, *he2;
+	lwres_context_t *lwrctx = NULL;
+	lwres_gnbaresponse_t *by = NULL;
+	lwres_result_t n;
+	union {
+		const void *konst;
+		struct in6_addr *in6;
+	} u;
+
+	/*
+	 * Sanity checks.
+	 */
+	if (src == NULL) {
+		*error_num = NO_RECOVERY;
+		return (NULL);
+	}
+
+	switch (af) {
+	case AF_INET:
+		if (len != (unsigned int)INADDRSZ) {
+			*error_num = NO_RECOVERY;
+			return (NULL);
+		}
+		break;
+	case AF_INET6:
+		if (len != (unsigned int)IN6ADDRSZ) {
+			*error_num = NO_RECOVERY;
+			return (NULL);
+		}
+		break;
+	default:
+		*error_num = NO_RECOVERY;
+		return (NULL);
+	}
+
+	/*
+	 * The de-"const"-ing game is done because at least one
+	 * vendor's system (RedHat 6.0) defines the IN6_IS_ADDR_*
+	 * macros in such a way that they discard the const with
+	 * internal casting, and gcc ends up complaining.  Rather
+	 * than replacing their own (possibly optimized) definitions
+	 * with our own, cleanly discarding the const is the easiest
+	 * thing to do.
+	 */
+	u.konst = src;
+
+	/*
+	 * Look up IPv4 and IPv4 mapped/compatible addresses.
+	 */
+	if ((af == AF_INET6 && IN6_IS_ADDR_V4COMPAT(u.in6)) ||
+	    (af == AF_INET6 && IN6_IS_ADDR_V4MAPPED(u.in6)) ||
+	    (af == AF_INET)) {
+		const unsigned char *cp = src;
+
+		if (af == AF_INET6)
+			cp += 12;
+		n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
+		if (n == LWRES_R_SUCCESS)
+			(void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
+		if (n == LWRES_R_SUCCESS)
+			n = lwres_getnamebyaddr(lwrctx, LWRES_ADDRTYPE_V4,
+						INADDRSZ, cp, &by);
+		if (n != LWRES_R_SUCCESS) {
+			lwres_conf_clear(lwrctx);
+			lwres_context_destroy(&lwrctx);
+			if (n == LWRES_R_NOTFOUND)
+				*error_num = HOST_NOT_FOUND;
+			else
+				*error_num = NO_RECOVERY;
+			return (NULL);
+		}
+		he1 = hostfromaddr(by, AF_INET, cp);
+		lwres_gnbaresponse_free(lwrctx, &by);
+		lwres_conf_clear(lwrctx);
+		lwres_context_destroy(&lwrctx);
+		if (af != AF_INET6)
+			return (he1);
+
+		/*
+		 * Convert from AF_INET to AF_INET6.
+		 */
+		he2 = copyandmerge(he1, NULL, af, error_num);
+		lwres_freehostent(he1);
+		if (he2 == NULL)
+			return (NULL);
+		/*
+		 * Restore original address.
+		 */
+		memmove(he2->h_addr, src, len);
+		return (he2);
+	}
+
+	/*
+	 * Lookup IPv6 address.
+	 */
+	if (memcmp(src, &in6addr_any, IN6ADDRSZ) == 0) {
+		*error_num = HOST_NOT_FOUND;
+		return (NULL);
+	}
+
+	n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
+	if (n == LWRES_R_SUCCESS)
+		(void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
+	if (n == LWRES_R_SUCCESS)
+		n = lwres_getnamebyaddr(lwrctx, LWRES_ADDRTYPE_V6, IN6ADDRSZ,
+					src, &by);
+	if (n != 0) {
+		lwres_conf_clear(lwrctx);
+		lwres_context_destroy(&lwrctx);
+
+		if (n == LWRES_R_NOTFOUND)
+		       *error_num = HOST_NOT_FOUND;
+		else
+		       *error_num = NO_RECOVERY;
+
+		return (NULL);
+	}
+
+	he1 = hostfromaddr(by, AF_INET6, src);
+	lwres_gnbaresponse_free(lwrctx, &by);
+	if (he1 == NULL)
+		*error_num = NO_RECOVERY;
+	lwres_conf_clear(lwrctx);
+	lwres_context_destroy(&lwrctx);
+	return (he1);
+}
+
+/*% releases all the memory associated with the struct hostent pointer */
+void
+lwres_freehostent(struct hostent *he) {
+	char **cpp;
+	int names = 1;
+	int addresses = 1;
+
+	if (he == NULL)
+		return;
+
+	free(he->h_name);
+
+	cpp = he->h_addr_list;
+	while (*cpp != NULL) {
+		free(*cpp);
+		*cpp = NULL;
+		cpp++;
+		addresses++;
+	}
+
+	cpp = he->h_aliases;
+	while (*cpp != NULL) {
+		free(*cpp);
+		cpp++;
+		names++;
+	}
+
+	free(he->h_aliases);
+	free(he->h_addr_list);
+	free(he);
+}
+
+/*
+ * Private
+ */
+
+/*
+ * Scan the interface table and set have_v4 and have_v6 depending
+ * upon whether there are IPv4 and IPv6 interface addresses.
+ *
+ * Returns:
+ *	0 on success
+ *	-1 on failure.
+ */
+
+#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR) && \
+    !defined(IRIX_EMUL_IOCTL_SIOCGIFCONF)
+
+#ifdef __hpux
+#define lifc_len iflc_len
+#define lifc_buf iflc_buf
+#define lifc_req iflc_req
+#define LIFCONF if_laddrconf
+#else
+#define ISC_HAVE_LIFC_FAMILY 1
+#define ISC_HAVE_LIFC_FLAGS 1
+#define LIFCONF lifconf
+#endif
+
+#ifdef __hpux
+#define lifr_addr iflr_addr
+#define lifr_name iflr_name
+#define lifr_dstaddr iflr_dstaddr
+#define lifr_flags iflr_flags
+#define ss_family sa_family
+#define LIFREQ if_laddrreq
+#else
+#define LIFREQ lifreq
+#endif
+
+static int
+scan_interfaces6(int *have_v4, int *have_v6) {
+	struct LIFCONF lifc;
+	struct LIFREQ lifreq;
+	struct in_addr in4;
+	struct in6_addr in6;
+	char *buf = NULL, *cp, *cplim;
+	static unsigned int bufsiz = 4095;
+	int s, cpsize, n;
+
+	/*
+	 * Set to zero.  Used as loop terminators below.
+	 */
+	*have_v4 = *have_v6 = 0;
+
+	/*
+	 * Get interface list from system.
+	 */
+	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) == -1)
+		goto err_ret;
+
+	/*
+	 * Grow buffer until large enough to contain all interface
+	 * descriptions.
+	 */
+	for (;;) {
+		buf = malloc(bufsiz);
+		if (buf == NULL)
+			goto err_ret;
+#ifdef ISC_HAVE_LIFC_FAMILY
+		lifc.lifc_family = AF_UNSPEC;	/* request all families */
+#endif
+#ifdef ISC_HAVE_LIFC_FLAGS
+		lifc.lifc_flags = 0;
+#endif
+		lifc.lifc_len = bufsiz;
+		lifc.lifc_buf = buf;
+		if ((n = ioctl(s, SIOCGLIFCONF, (char *)&lifc)) != -1) {
+			/*
+			 * Some OS's just return what will fit rather
+			 * than set EINVAL if the buffer is too small
+			 * to fit all the interfaces in.  If
+			 * lifc.lifc_len is too near to the end of the
+			 * buffer we will grow it just in case and
+			 * retry.
+			 */
+			if (lifc.lifc_len + 2 * sizeof(lifreq) < bufsiz)
+				break;
+		}
+		if ((n == -1) && errno != EINVAL)
+			goto err_ret;
+
+		if (bufsiz > 1000000)
+			goto err_ret;
+
+		free(buf);
+		bufsiz += 4096;
+	}
+
+	/*
+	 * Parse system's interface list.
+	 */
+	cplim = buf + lifc.lifc_len;    /* skip over if's with big ifr_addr's */
+	for (cp = buf;
+	     (*have_v4 == 0 || *have_v6 == 0) && cp < cplim;
+	     cp += cpsize) {
+		memmove(&lifreq, cp, sizeof(lifreq));
+#ifdef LWRES_PLATFORM_HAVESALEN
+#ifdef FIX_ZERO_SA_LEN
+		if (lifreq.lifr_addr.sa_len == 0)
+			lifreq.lifr_addr.sa_len = 16;
+#endif
+#ifdef HAVE_MINIMUM_IFREQ
+		cpsize = sizeof(lifreq);
+		if (lifreq.lifr_addr.sa_len > sizeof(struct sockaddr))
+			cpsize += (int)lifreq.lifr_addr.sa_len -
+				(int)(sizeof(struct sockaddr));
+#else
+		cpsize = sizeof(lifreq.lifr_name) + lifreq.lifr_addr.sa_len;
+#endif /* HAVE_MINIMUM_IFREQ */
+#elif defined SIOCGIFCONF_ADDR
+		cpsize = sizeof(lifreq);
+#else
+		cpsize = sizeof(lifreq.lifr_name);
+		/* XXX maybe this should be a hard error? */
+		if (ioctl(s, SIOCGLIFADDR, (char *)&lifreq) < 0)
+			continue;
+#endif
+		switch (lifreq.lifr_addr.ss_family) {
+		case AF_INET:
+			if (*have_v4 == 0) {
+				memmove(&in4,
+					&((struct sockaddr_in *)
+					  &lifreq.lifr_addr)->sin_addr,
+					sizeof(in4));
+				if (in4.s_addr == INADDR_ANY)
+					break;
+				n = ioctl(s, SIOCGLIFFLAGS, (char *)&lifreq);
+				if (n < 0)
+					break;
+				if ((lifreq.lifr_flags & IFF_UP) == 0)
+					break;
+				*have_v4 = 1;
+			}
+			break;
+		case AF_INET6:
+			if (*have_v6 == 0) {
+				memmove(&in6,
+					&((struct sockaddr_in6 *)
+					  &lifreq.lifr_addr)->sin6_addr,
+					sizeof(in6));
+				if (memcmp(&in6, &in6addr_any,
+					   sizeof(in6)) == 0)
+					break;
+				n = ioctl(s, SIOCGLIFFLAGS, (char *)&lifreq);
+				if (n < 0)
+					break;
+				if ((lifreq.lifr_flags & IFF_UP) == 0)
+					break;
+				*have_v6 = 1;
+			}
+			break;
+		}
+	}
+	if (buf != NULL)
+		free(buf);
+	close(s);
+	return (0);
+ err_ret:
+	if (buf != NULL)
+		free(buf);
+	if (s != -1)
+		close(s);
+	return (-1);
+}
+#endif
+
+static int
+scan_interfaces(int *have_v4, int *have_v6) {
+#if !defined(SIOCGIFCONF) || !defined(SIOCGIFADDR)
+	*have_v4 = *have_v6 = 1;
+	return (0);
+#else
+	struct ifconf ifc;
+	union {
+		char _pad[256];		/* leave space for IPv6 addresses */
+		struct ifreq ifreq;
+	} u;
+	struct in_addr in4;
+	struct in6_addr in6;
+	char *buf = NULL, *cp, *cplim;
+	static unsigned int bufsiz = 4095;
+	int s, n;
+	size_t cpsize;
+
+#ifdef WIN32
+	InitSockets();
+#endif
+#if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR) && \
+    !defined(IRIX_EMUL_IOCTL_SIOCGIFCONF)
+	/*
+	 * Try to scan the interfaces using IPv6 ioctls().
+	 */
+	if (!scan_interfaces6(have_v4, have_v6)) {
+#ifdef WIN32
+		DestroySockets();
+#endif
+		return (0);
+	}
+#endif
+
+	/*
+	 * Set to zero.  Used as loop terminators below.
+	 */
+	*have_v4 = *have_v6 = 0;
+
+	/*
+	 * Get interface list from system.
+	 */
+	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
+		goto err_ret;
+
+	/*
+	 * Grow buffer until large enough to contain all interface
+	 * descriptions.
+	 */
+	for (;;) {
+		buf = malloc(bufsiz);
+		if (buf == NULL)
+			goto err_ret;
+		ifc.ifc_len = bufsiz;
+		ifc.ifc_buf = buf;
+#ifdef IRIX_EMUL_IOCTL_SIOCGIFCONF
+		/*
+		 * This is a fix for IRIX OS in which the call to ioctl with
+		 * the flag SIOCGIFCONF may not return an entry for all the
+		 * interfaces like most flavors of Unix.
+		 */
+		if (emul_ioctl(&ifc) >= 0)
+			break;
+#else
+		if ((n = ioctl(s, SIOCGIFCONF, (char *)&ifc)) != -1) {
+			/*
+			 * Some OS's just return what will fit rather
+			 * than set EINVAL if the buffer is too small
+			 * to fit all the interfaces in.  If
+			 * ifc.ifc_len is too near to the end of the
+			 * buffer we will grow it just in case and
+			 * retry.
+			 */
+			if (ifc.ifc_len + 2 * sizeof(u.ifreq) < bufsiz)
+				break;
+		}
+#endif
+		if ((n == -1) && errno != EINVAL)
+			goto err_ret;
+
+		if (bufsiz > 1000000)
+			goto err_ret;
+
+		free(buf);
+		bufsiz += 4096;
+	}
+
+	/*
+	 * Parse system's interface list.
+	 */
+	cplim = buf + ifc.ifc_len;    /* skip over if's with big ifr_addr's */
+	for (cp = buf;
+	     (*have_v4 == 0 || *have_v6 == 0) && cp < cplim;
+	     cp += cpsize) {
+		memmove(&u.ifreq, cp, sizeof(u.ifreq));
+#ifdef LWRES_PLATFORM_HAVESALEN
+#ifdef FIX_ZERO_SA_LEN
+		if (u.ifreq.ifr_addr.sa_len == 0)
+			u.ifreq.ifr_addr.sa_len = 16;
+#endif
+#ifdef HAVE_MINIMUM_IFREQ
+		cpsize = sizeof(u.ifreq);
+		if (u.ifreq.ifr_addr.sa_len > sizeof(struct sockaddr))
+			cpsize += (int)u.ifreq.ifr_addr.sa_len -
+				(int)(sizeof(struct sockaddr));
+#else
+		cpsize = sizeof(u.ifreq.ifr_name) + u.ifreq.ifr_addr.sa_len;
+#endif /* HAVE_MINIMUM_IFREQ */
+		if (cpsize > sizeof(u.ifreq) && cpsize <= sizeof(u))
+			memmove(&u.ifreq, cp, cpsize);
+#elif defined SIOCGIFCONF_ADDR
+		cpsize = sizeof(u.ifreq);
+#else
+		cpsize = sizeof(u.ifreq.ifr_name);
+		/* XXX maybe this should be a hard error? */
+		if (ioctl(s, SIOCGIFADDR, (char *)&u.ifreq) < 0)
+			continue;
+#endif
+		switch (u.ifreq.ifr_addr.sa_family) {
+		case AF_INET:
+			if (*have_v4 == 0) {
+				memmove(&in4,
+					&((struct sockaddr_in *)
+					  &u.ifreq.ifr_addr)->sin_addr,
+					sizeof(in4));
+				if (in4.s_addr == INADDR_ANY)
+					break;
+				n = ioctl(s, SIOCGIFFLAGS, (char *)&u.ifreq);
+				if (n < 0)
+					break;
+				if ((u.ifreq.ifr_flags & IFF_UP) == 0)
+					break;
+				*have_v4 = 1;
+			}
+			break;
+		case AF_INET6:
+			if (*have_v6 == 0) {
+				memmove(&in6,
+					&((struct sockaddr_in6 *)
+					  &u.ifreq.ifr_addr)->sin6_addr,
+					sizeof(in6));
+				if (memcmp(&in6, &in6addr_any,
+					   sizeof(in6)) == 0)
+					break;
+				n = ioctl(s, SIOCGIFFLAGS, (char *)&u.ifreq);
+				if (n < 0)
+					break;
+				if ((u.ifreq.ifr_flags & IFF_UP) == 0)
+					break;
+				*have_v6 = 1;
+			}
+			break;
+		}
+	}
+	if (buf != NULL)
+		free(buf);
+#ifdef WIN32
+	DestroySockets();
+#endif
+	close(s);
+	return (0);
+
+ err_ret:
+	if (buf != NULL)
+		free(buf);
+	if (s != -1)
+		close(s);
+#ifdef WIN32
+	DestroySockets();
+#endif
+	return (-1);
+#endif
+}
+
+static struct hostent *
+copyandmerge(struct hostent *he1, struct hostent *he2, int af, int *error_num)
+{
+	struct hostent *he = NULL;
+	int addresses = 1;	/* NULL terminator */
+	int names = 1;		/* NULL terminator */
+	int len = 0;
+	char **cpp, **npp;
+
+	/*
+	 * Work out array sizes.
+	 */
+	if (he1 != NULL) {
+		cpp = he1->h_addr_list;
+		while (*cpp != NULL) {
+			addresses++;
+			cpp++;
+		}
+		cpp = he1->h_aliases;
+		while (*cpp != NULL) {
+			names++;
+			cpp++;
+		}
+	}
+
+	if (he2 != NULL) {
+		cpp = he2->h_addr_list;
+		while (*cpp != NULL) {
+			addresses++;
+			cpp++;
+		}
+		if (he1 == NULL) {
+			cpp = he2->h_aliases;
+			while (*cpp != NULL) {
+				names++;
+				cpp++;
+			}
+		}
+	}
+
+	if (addresses == 1) {
+		*error_num = NO_ADDRESS;
+		return (NULL);
+	}
+
+	he = malloc(sizeof(*he));
+	if (he == NULL)
+		goto no_recovery;
+
+	he->h_addr_list = malloc(sizeof(char *) * (addresses));
+	if (he->h_addr_list == NULL)
+		goto cleanup0;
+	memset(he->h_addr_list, 0, sizeof(char *) * (addresses));
+
+	/*
+	 * Copy addresses.
+	 */
+	npp = he->h_addr_list;
+	if (he1 != NULL) {
+		cpp = he1->h_addr_list;
+		while (*cpp != NULL) {
+			*npp = malloc((af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
+			if (*npp == NULL)
+				goto cleanup1;
+			/*
+			 * Convert to mapped if required.
+			 */
+			if (af == AF_INET6 && he1->h_addrtype == AF_INET) {
+				memmove(*npp, in6addr_mapped,
+					sizeof(in6addr_mapped));
+				memmove(*npp + sizeof(in6addr_mapped), *cpp,
+					INADDRSZ);
+			} else {
+				memmove(*npp, *cpp,
+					(af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
+			}
+			cpp++;
+			npp++;
+		}
+	}
+
+	if (he2 != NULL) {
+		cpp = he2->h_addr_list;
+		while (*cpp != NULL) {
+			*npp = malloc((af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
+			if (*npp == NULL)
+				goto cleanup1;
+			/*
+			 * Convert to mapped if required.
+			 */
+			if (af == AF_INET6 && he2->h_addrtype == AF_INET) {
+				memmove(*npp, in6addr_mapped,
+					sizeof(in6addr_mapped));
+				memmove(*npp + sizeof(in6addr_mapped), *cpp,
+					INADDRSZ);
+			} else {
+				memmove(*npp, *cpp,
+					(af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
+			}
+			cpp++;
+			npp++;
+		}
+	}
+
+	he->h_aliases = malloc(sizeof(char *) * (names));
+	if (he->h_aliases == NULL)
+		goto cleanup1;
+	memset(he->h_aliases, 0, sizeof(char *) * (names));
+
+	/*
+	 * Copy aliases.
+	 */
+	npp = he->h_aliases;
+	cpp = (he1 != NULL) ? he1->h_aliases
+		: ((he2 != NULL) ?  he2->h_aliases : NULL);
+	while (cpp != NULL && *cpp != NULL) {
+		len = strlen (*cpp) + 1;
+		*npp = malloc(len);
+		if (*npp == NULL)
+			goto cleanup2;
+		strcpy(*npp, *cpp);
+		npp++;
+		cpp++;
+	}
+
+	/*
+	 * Copy hostname.
+	 */
+	he->h_name = malloc(strlen((he1 != NULL) ?
+			    he1->h_name : he2->h_name) + 1);
+	if (he->h_name == NULL)
+		goto cleanup2;
+	strcpy(he->h_name, (he1 != NULL) ? he1->h_name : he2->h_name);
+
+	/*
+	 * Set address type and length.
+	 */
+	he->h_addrtype = af;
+	he->h_length = (af == AF_INET) ? INADDRSZ : IN6ADDRSZ;
+	return (he);
+
+ cleanup2:
+	cpp = he->h_aliases;
+	while (*cpp != NULL) {
+		free(*cpp);
+		cpp++;
+	}
+	free(he->h_aliases);
+
+ cleanup1:
+	cpp = he->h_addr_list;
+	while (*cpp != NULL) {
+		free(*cpp);
+		*cpp = NULL;
+		cpp++;
+	}
+	free(he->h_addr_list);
+
+ cleanup0:
+	free(he);
+
+ no_recovery:
+	*error_num = NO_RECOVERY;
+	return (NULL);
+}
+
+static struct hostent *
+hostfromaddr(lwres_gnbaresponse_t *addr, int af, const void *src) {
+	struct hostent *he;
+	int i;
+
+	he = malloc(sizeof(*he));
+	if (he == NULL)
+		goto cleanup;
+	memset(he, 0, sizeof(*he));
+
+	/*
+	 * Set family and length.
+	 */
+	he->h_addrtype = af;
+	switch (af) {
+	case AF_INET:
+		he->h_length = INADDRSZ;
+		break;
+	case AF_INET6:
+		he->h_length = IN6ADDRSZ;
+		break;
+	default:
+		INSIST(0);
+	}
+
+	/*
+	 * Copy name.
+	 */
+	he->h_name = strdup(addr->realname);
+	if (he->h_name == NULL)
+		goto cleanup;
+
+	/*
+	 * Copy aliases.
+	 */
+	he->h_aliases = malloc(sizeof(char *) * (addr->naliases + 1));
+	if (he->h_aliases == NULL)
+		goto cleanup;
+	for (i = 0; i < addr->naliases; i++) {
+		he->h_aliases[i] = strdup(addr->aliases[i]);
+		if (he->h_aliases[i] == NULL)
+			goto cleanup;
+	}
+	he->h_aliases[i] = NULL;
+
+	/*
+	 * Copy address.
+	 */
+	he->h_addr_list = malloc(sizeof(char *) * 2);
+	if (he->h_addr_list == NULL)
+		goto cleanup;
+	he->h_addr_list[0] = malloc(he->h_length);
+	if (he->h_addr_list[0] == NULL)
+		goto cleanup;
+	memmove(he->h_addr_list[0], src, he->h_length);
+	he->h_addr_list[1] = NULL;
+	return (he);
+
+ cleanup:
+	if (he != NULL && he->h_addr_list != NULL) {
+		for (i = 0; he->h_addr_list[i] != NULL; i++)
+			free(he->h_addr_list[i]);
+		free(he->h_addr_list);
+	}
+	if (he != NULL && he->h_aliases != NULL) {
+		for (i = 0; he->h_aliases[i] != NULL; i++)
+			free(he->h_aliases[i]);
+		free(he->h_aliases);
+	}
+	if (he != NULL && he->h_name != NULL)
+		free(he->h_name);
+	if (he != NULL)
+		free(he);
+	return (NULL);
+}
+
+static struct hostent *
+hostfromname(lwres_gabnresponse_t *name, int af) {
+	struct hostent *he;
+	int i;
+	lwres_addr_t *addr;
+
+	he = malloc(sizeof(*he));
+	if (he == NULL)
+		goto cleanup;
+	memset(he, 0, sizeof(*he));
+
+	/*
+	 * Set family and length.
+	 */
+	he->h_addrtype = af;
+	switch (af) {
+	case AF_INET:
+		he->h_length = INADDRSZ;
+		break;
+	case AF_INET6:
+		he->h_length = IN6ADDRSZ;
+		break;
+	default:
+		INSIST(0);
+	}
+
+	/*
+	 * Copy name.
+	 */
+	he->h_name = strdup(name->realname);
+	if (he->h_name == NULL)
+		goto cleanup;
+
+	/*
+	 * Copy aliases.
+	 */
+	he->h_aliases = malloc(sizeof(char *) * (name->naliases + 1));
+	if (he->h_aliases == NULL)
+		goto cleanup;
+	for (i = 0; i < name->naliases; i++) {
+		he->h_aliases[i] = strdup(name->aliases[i]);
+		if (he->h_aliases[i] == NULL)
+			goto cleanup;
+	}
+	he->h_aliases[i] = NULL;
+
+	/*
+	 * Copy addresses.
+	 */
+	he->h_addr_list = malloc(sizeof(char *) * (name->naddrs + 1));
+	if (he->h_addr_list == NULL)
+		goto cleanup;
+	addr = LWRES_LIST_HEAD(name->addrs);
+	i = 0;
+	while (addr != NULL) {
+		he->h_addr_list[i] = malloc(he->h_length);
+		if (he->h_addr_list[i] == NULL)
+			goto cleanup;
+		memmove(he->h_addr_list[i], addr->address, he->h_length);
+		addr = LWRES_LIST_NEXT(addr, link);
+		i++;
+	}
+	he->h_addr_list[i] = NULL;
+	return (he);
+
+ cleanup:
+	if (he != NULL && he->h_addr_list != NULL) {
+		for (i = 0; he->h_addr_list[i] != NULL; i++)
+			free(he->h_addr_list[i]);
+		free(he->h_addr_list);
+	}
+	if (he != NULL && he->h_aliases != NULL) {
+		for (i = 0; he->h_aliases[i] != NULL; i++)
+			free(he->h_aliases[i]);
+		free(he->h_aliases);
+	}
+	if (he != NULL && he->h_name != NULL)
+		free(he->h_name);
+	if (he != NULL)
+		free(he);
+	return (NULL);
+}