r17586: merge lib/netif into lib/socket and use -lnsl -lsocket on the

configure check for the interfaces.

should fix the build on some old sun boxes

metze
(This used to be commit f20e251bfd9f1eb7ce5c00739631b1625a2aa467)

5 files changed, 851 insertions, 0 deletions

diff --git a/source4/lib/socket/config.m4 b/source4/lib/socket/config.m4
index 7ea7e2b809..0965cd1245 100644
--- a/source4/lib/socket/config.m4
+++ b/source4/lib/socket/config.m4
@@ -97,3 +97,54 @@ if $have_ipv6 = true; then
 fi
 dnl don't build ipv6 by default, unless the above test enables it, or
 dnl the configure uses --with-static-modules=socket_ipv6
+
+AC_CHECK_HEADERS(arpa/inet.h net/if.h netdb.h netinet/in.h sys/time.h)
+AC_CHECK_HEADERS(netinet/ip.h netinet/tcp.h netinet/in_systm.h netinet/in_ip.h)
+
+
+##################
+# look for a method of finding the list of network interfaces
+#
+# This tests need LIBS="$NSL_LIBS $SOCKET_LIBS"
+#
+old_LIBS=$LIBS
+LIBS="$NSL_LIBS $SOCKET_LIBS"
+iface=no;
+AC_CACHE_CHECK([for iface AIX],samba_cv_HAVE_IFACE_AIX,[
+AC_TRY_RUN([
+#define HAVE_IFACE_AIX 1
+#define AUTOCONF_TEST 1
+#include "confdefs.h"
+#include "${srcdir-.}/lib/socket/netif.c"],
+           samba_cv_HAVE_IFACE_AIX=yes,samba_cv_HAVE_IFACE_AIX=no,samba_cv_HAVE_IFACE_AIX=cross)])
+if test x"$samba_cv_HAVE_IFACE_AIX" = x"yes"; then
+    iface=yes;AC_DEFINE(HAVE_IFACE_AIX,1,[Whether iface AIX is available])
+fi
+
+if test $iface = no; then
+AC_CACHE_CHECK([for iface ifconf],samba_cv_HAVE_IFACE_IFCONF,[
+AC_TRY_RUN([
+#define HAVE_IFACE_IFCONF 1
+#define AUTOCONF_TEST 1
+#include "confdefs.h"
+#include "${srcdir-.}/lib/socket/netif.c"],
+           samba_cv_HAVE_IFACE_IFCONF=yes,samba_cv_HAVE_IFACE_IFCONF=no,samba_cv_HAVE_IFACE_IFCONF=cross)])
+if test x"$samba_cv_HAVE_IFACE_IFCONF" = x"yes"; then
+    iface=yes;AC_DEFINE(HAVE_IFACE_IFCONF,1,[Whether iface ifconf is available])
+fi
+fi
+
+if test $iface = no; then
+AC_CACHE_CHECK([for iface ifreq],samba_cv_HAVE_IFACE_IFREQ,[
+AC_TRY_RUN([
+#define HAVE_IFACE_IFREQ 1
+#define AUTOCONF_TEST 1
+#include "confdefs.h"
+#include "${srcdir-.}/lib/socket/netif.c"],
+           samba_cv_HAVE_IFACE_IFREQ=yes,samba_cv_HAVE_IFACE_IFREQ=no,samba_cv_HAVE_IFACE_IFREQ=cross)])
+if test x"$samba_cv_HAVE_IFACE_IFREQ" = x"yes"; then
+    iface=yes;AC_DEFINE(HAVE_IFACE_IFREQ,1,[Whether iface ifreq is available])
+fi
+fi
+
+LIBS=$old_LIBS
diff --git a/source4/lib/socket/config.mk b/source4/lib/socket/config.mk
index 1e22edb1d7..a823efb23e 100644
--- a/source4/lib/socket/config.mk
+++ b/source4/lib/socket/config.mk
@@ -1,3 +1,13 @@
+##############################
+# Start SUBSYSTEM LIBNETIF
+[SUBSYSTEM::LIBNETIF]
+PRIVATE_PROTO_HEADER = netif_proto.h
+OBJ_FILES = \
+		interface.o \
+		netif.o
+PRIVATE_DEPENDENCIES = LIBSAMBA-UTIL EXT_SOCKET EXT_NSL
+# End SUBSYSTEM LIBNETIF
+##############################
 
 ################################################
 # Start MODULE socket_ipv4
diff --git a/source4/lib/socket/interface.c b/source4/lib/socket/interface.c
new file mode 100644
index 0000000000..5b2b4fd1ab
--- /dev/null
+++ b/source4/lib/socket/interface.c
@@ -0,0 +1,354 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   multiple interface handling
+
+   Copyright (C) Andrew Tridgell 1992-2005
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+#include "system/network.h"
+#include "lib/socket/netif.h"
+#include "dlinklist.h"
+
+/** used for network interfaces */
+struct interface {
+	struct interface *next, *prev;
+	struct ipv4_addr ip;
+	struct ipv4_addr nmask;
+	const char *ip_s;
+	const char *bcast_s;
+	const char *nmask_s;
+};
+
+static struct interface *local_interfaces;
+
+#define ALLONES  ((uint32_t)0xFFFFFFFF)
+/*
+  address construction based on a patch from fred@datalync.com
+*/
+#define MKBCADDR(_IP, _NM) ((_IP & _NM) | (_NM ^ ALLONES))
+#define MKNETADDR(_IP, _NM) (_IP & _NM)
+
+static struct ipv4_addr tov4(struct in_addr in)
+{
+	struct ipv4_addr in2;
+	in2.addr = in.s_addr;
+	return in2;
+}
+
+/****************************************************************************
+Try and find an interface that matches an ip. If we cannot, return NULL
+  **************************************************************************/
+static struct interface *iface_find(struct in_addr ip, BOOL CheckMask)
+{
+	struct interface *i;
+	if (is_zero_ip(tov4(ip))) return local_interfaces;
+
+	for (i=local_interfaces;i;i=i->next)
+		if (CheckMask) {
+			if (same_net(i->ip,tov4(ip),i->nmask)) return i;
+		} else if (i->ip.addr == ip.s_addr) return i;
+
+	return NULL;
+}
+
+
+/****************************************************************************
+add an interface to the linked list of interfaces
+****************************************************************************/
+static void add_interface(struct in_addr ip, struct in_addr nmask)
+{
+	struct interface *iface;
+	struct ipv4_addr bcast;
+	if (iface_find(ip, False)) {
+		DEBUG(3,("not adding duplicate interface %s\n",inet_ntoa(ip)));
+		return;
+	}
+
+	iface = talloc(local_interfaces, struct interface);
+	if (!iface) return;
+	
+	ZERO_STRUCTPN(iface);
+
+	iface->ip = tov4(ip);
+	iface->nmask = tov4(nmask);
+	bcast.addr = MKBCADDR(iface->ip.addr, iface->nmask.addr);
+
+	/* keep string versions too, to avoid people tripping over the implied
+	   static in sys_inet_ntoa() */
+	iface->ip_s = talloc_strdup(iface, sys_inet_ntoa(iface->ip));
+	iface->nmask_s = talloc_strdup(iface, sys_inet_ntoa(iface->nmask));
+	
+	if (nmask.s_addr != ~0) {
+		iface->bcast_s = talloc_strdup(iface, sys_inet_ntoa(bcast));
+	}
+
+	DLIST_ADD_END(local_interfaces, iface, struct interface *);
+
+	DEBUG(2,("added interface ip=%s nmask=%s\n", iface->ip_s, iface->nmask_s));
+}
+
+
+
+/**
+interpret a single element from a interfaces= config line 
+
+This handles the following different forms:
+
+1) wildcard interface name
+2) DNS name
+3) IP/masklen
+4) ip/mask
+5) bcast/mask
+**/
+static void interpret_interface(const char *token, 
+				struct iface_struct *probed_ifaces, 
+				int total_probed)
+{
+	struct in_addr ip, nmask;
+	char *p;
+	int i, added=0;
+
+	ip.s_addr = 0;
+	nmask.s_addr = 0;
+	
+	/* first check if it is an interface name */
+	for (i=0;i<total_probed;i++) {
+		if (gen_fnmatch(token, probed_ifaces[i].name) == 0) {
+			add_interface(probed_ifaces[i].ip,
+				      probed_ifaces[i].netmask);
+			added = 1;
+		}
+	}
+	if (added) return;
+
+	/* maybe it is a DNS name */
+	p = strchr_m(token,'/');
+	if (!p) {
+		/* don't try to do dns lookups on wildcard names */
+		if (strpbrk(token, "*?") != NULL) {
+			return;
+		}
+		ip.s_addr = interpret_addr2(token).addr;
+		for (i=0;i<total_probed;i++) {
+			if (ip.s_addr == probed_ifaces[i].ip.s_addr) {
+				add_interface(probed_ifaces[i].ip,
+					      probed_ifaces[i].netmask);
+				return;
+			}
+		}
+		DEBUG(2,("can't determine netmask for %s\n", token));
+		return;
+	}
+
+	/* parse it into an IP address/netmasklength pair */
+	*p++ = 0;
+
+	ip.s_addr = interpret_addr2(token).addr;
+
+	if (strlen(p) > 2) {
+		nmask.s_addr = interpret_addr2(p).addr;
+	} else {
+		nmask.s_addr = htonl(((ALLONES >> atoi(p)) ^ ALLONES));
+	}
+
+	/* maybe the first component was a broadcast address */
+	if (ip.s_addr == MKBCADDR(ip.s_addr, nmask.s_addr) ||
+	    ip.s_addr == MKNETADDR(ip.s_addr, nmask.s_addr)) {
+		for (i=0;i<total_probed;i++) {
+			if (same_net(tov4(ip), tov4(probed_ifaces[i].ip), tov4(nmask))) {
+				add_interface(probed_ifaces[i].ip, nmask);
+				return;
+			}
+		}
+		DEBUG(2,("Can't determine ip for broadcast address %s\n", token));
+		return;
+	}
+
+	add_interface(ip, nmask);
+}
+
+
+/**
+load the list of network interfaces
+**/
+static void load_interfaces(void)
+{
+	const char **ptr;
+	int i;
+	struct iface_struct ifaces[MAX_INTERFACES];
+	struct ipv4_addr loopback_ip;
+	int total_probed;
+
+	if (local_interfaces != NULL) {
+		return;
+	}
+
+	ptr = lp_interfaces();
+	loopback_ip = interpret_addr2("127.0.0.1");
+
+	/* probe the kernel for interfaces */
+	total_probed = get_interfaces(ifaces, MAX_INTERFACES);
+
+	/* if we don't have a interfaces line then use all interfaces
+	   except loopback */
+	if (!ptr || !*ptr || !**ptr) {
+		if (total_probed <= 0) {
+			DEBUG(0,("ERROR: Could not determine network interfaces, you must use a interfaces config line\n"));
+		}
+		for (i=0;i<total_probed;i++) {
+			if (ifaces[i].ip.s_addr != loopback_ip.addr) {
+				add_interface(ifaces[i].ip, 
+					      ifaces[i].netmask);
+			}
+		}
+	}
+
+	while (ptr && *ptr) {
+		interpret_interface(*ptr, ifaces, total_probed);
+		ptr++;
+	}
+
+	if (!local_interfaces) {
+		DEBUG(0,("WARNING: no network interfaces found\n"));
+	}
+}
+
+
+/**
+  unload the interfaces list, so it can be reloaded when needed
+*/
+void unload_interfaces(void)
+{
+	talloc_free(local_interfaces);
+	local_interfaces = NULL;
+}
+
+/**
+  how many interfaces do we have
+  **/
+int iface_count(void)
+{
+	int ret = 0;
+	struct interface *i;
+
+	load_interfaces();
+
+	for (i=local_interfaces;i;i=i->next)
+		ret++;
+	return ret;
+}
+
+/**
+  return IP of the Nth interface
+  **/
+const char *iface_n_ip(int n)
+{
+	struct interface *i;
+  
+	load_interfaces();
+
+	for (i=local_interfaces;i && n;i=i->next)
+		n--;
+
+	if (i) {
+		return i->ip_s;
+	}
+	return NULL;
+}
+
+/**
+  return bcast of the Nth interface
+  **/
+const char *iface_n_bcast(int n)
+{
+	struct interface *i;
+  
+	load_interfaces();
+
+	for (i=local_interfaces;i && n;i=i->next)
+		n--;
+
+	if (i) {
+		return i->bcast_s;
+	}
+	return NULL;
+}
+
+/**
+  return netmask of the Nth interface
+  **/
+const char *iface_n_netmask(int n)
+{
+	struct interface *i;
+  
+	load_interfaces();
+
+	for (i=local_interfaces;i && n;i=i->next)
+		n--;
+
+	if (i) {
+		return i->nmask_s;
+	}
+	return NULL;
+}
+
+/**
+  return the local IP address that best matches a destination IP, or
+  our first interface if none match
+*/
+const char *iface_best_ip(const char *dest)
+{
+	struct interface *iface;
+	struct in_addr ip;
+
+	load_interfaces();
+
+	ip.s_addr = interpret_addr(dest);
+	iface = iface_find(ip, True);
+	if (iface) {
+		return iface->ip_s;
+	}
+	return iface_n_ip(0);
+}
+
+/**
+  return True if an IP is one one of our local networks
+*/
+BOOL iface_is_local(const char *dest)
+{
+	struct in_addr ip;
+
+	load_interfaces();
+
+	ip.s_addr = interpret_addr(dest);
+	if (iface_find(ip, True)) {
+		return True;
+	}
+	return False;
+}
+
+/**
+  return True if a IP matches a IP/netmask pair
+*/
+BOOL iface_same_net(const char *ip1, const char *ip2, const char *netmask)
+{
+	return same_net(interpret_addr2(ip1),
+			interpret_addr2(ip2),
+			interpret_addr2(netmask));
+}
diff --git a/source4/lib/socket/netif.c b/source4/lib/socket/netif.c
new file mode 100644
index 0000000000..0344febf38
--- /dev/null
+++ b/source4/lib/socket/netif.c
@@ -0,0 +1,403 @@
+/* 
+   Unix SMB/CIFS implementation.
+   return a list of network interfaces
+   Copyright (C) Andrew Tridgell 1998
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+
+/* working out the interfaces for a OS is an incredibly non-portable
+   thing. We have several possible implementations below, and autoconf
+   tries each of them to see what works
+
+   Note that this file does _not_ include includes.h. That is so this code
+   can be called directly from the autoconf tests. That also means
+   this code cannot use any of the normal Samba debug stuff or defines.
+   This is standalone code.
+
+*/
+
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <netdb.h>
+#include <sys/ioctl.h>
+#include <netdb.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#ifndef AUTOCONF_TEST
+#include "config.h"
+#endif
+
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+#ifndef SIOCGIFCONF
+#ifdef HAVE_SYS_SOCKIO_H
+#include <sys/sockio.h>
+#endif
+#endif
+
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+
+#ifdef HAVE_STRINGS_H
+#include <strings.h>
+#endif
+
+#ifdef __COMPAR_FN_T
+#define QSORT_CAST (__compar_fn_t)
+#endif
+
+#ifndef QSORT_CAST
+#define QSORT_CAST (int (*)(const void *, const void *))
+#endif
+
+#include <net/if.h>
+#define BOOL int
+#include "netif.h"
+
+#if HAVE_IFACE_IFCONF
+
+/* this works for Linux 2.2, Solaris 2.5, SunOS4, HPUX 10.20, OSF1
+   V4.0, Ultrix 4.4, SCO Unix 3.2, IRIX 6.4 and FreeBSD 3.2.
+
+   It probably also works on any BSD style system.  */
+
+/****************************************************************************
+  get the netmask address for a local interface
+****************************************************************************/
+static int _get_interfaces(struct iface_struct *ifaces, int max_interfaces)
+{  
+	struct ifconf ifc;
+	char buff[8192];
+	int fd, i, n;
+	struct ifreq *ifr=NULL;
+	int total = 0;
+	struct in_addr ipaddr;
+	struct in_addr nmask;
+	char *iname;
+
+	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
+		return -1;
+	}
+  
+	ifc.ifc_len = sizeof(buff);
+	ifc.ifc_buf = buff;
+
+	if (ioctl(fd, SIOCGIFCONF, &ifc) != 0) {
+		close(fd);
+		return -1;
+	} 
+
+	ifr = ifc.ifc_req;
+  
+	n = ifc.ifc_len / sizeof(struct ifreq);
+
+	/* Loop through interfaces, looking for given IP address */
+	for (i=n-1;i>=0 && total < max_interfaces;i--) {
+		if (ioctl(fd, SIOCGIFADDR, &ifr[i]) != 0) {
+			continue;
+		}
+
+		iname = ifr[i].ifr_name;
+		ipaddr = (*(struct sockaddr_in *)&ifr[i].ifr_addr).sin_addr;
+
+		if (ioctl(fd, SIOCGIFFLAGS, &ifr[i]) != 0) {
+			continue;
+		}  
+
+		if (!(ifr[i].ifr_flags & IFF_UP)) {
+			continue;
+		}
+
+		if (ioctl(fd, SIOCGIFNETMASK, &ifr[i]) != 0) {
+			continue;
+		}  
+
+		nmask = ((struct sockaddr_in *)&ifr[i].ifr_addr)->sin_addr;
+
+		strncpy(ifaces[total].name, iname, sizeof(ifaces[total].name)-1);
+		ifaces[total].name[sizeof(ifaces[total].name)-1] = 0;
+		ifaces[total].ip = ipaddr;
+		ifaces[total].netmask = nmask;
+		total++;
+	}
+
+	close(fd);
+
+	return total;
+}  
+
+#elif HAVE_IFACE_IFREQ
+
+#ifndef I_STR
+#include <sys/stropts.h>
+#endif
+
+/****************************************************************************
+this should cover most of the streams based systems
+Thanks to Andrej.Borsenkow@mow.siemens.ru for several ideas in this code
+****************************************************************************/
+static int _get_interfaces(struct iface_struct *ifaces, int max_interfaces)
+{
+	struct ifreq ifreq;
+	struct strioctl strioctl;
+	char buff[8192];
+	int fd, i, n;
+	struct ifreq *ifr=NULL;
+	int total = 0;
+	struct in_addr ipaddr;
+	struct in_addr nmask;
+	char *iname;
+
+	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
+		return -1;
+	}
+  
+	strioctl.ic_cmd = SIOCGIFCONF;
+	strioctl.ic_dp  = buff;
+	strioctl.ic_len = sizeof(buff);
+	if (ioctl(fd, I_STR, &strioctl) < 0) {
+		close(fd);
+		return -1;
+	} 
+
+	/* we can ignore the possible sizeof(int) here as the resulting
+	   number of interface structures won't change */
+	n = strioctl.ic_len / sizeof(struct ifreq);
+
+	/* we will assume that the kernel returns the length as an int
+           at the start of the buffer if the offered size is a
+           multiple of the structure size plus an int */
+	if (n*sizeof(struct ifreq) + sizeof(int) == strioctl.ic_len) {
+		ifr = (struct ifreq *)(buff + sizeof(int));  
+	} else {
+		ifr = (struct ifreq *)buff;  
+	}
+
+	/* Loop through interfaces */
+
+	for (i = 0; i<n && total < max_interfaces; i++) {
+		ifreq = ifr[i];
+  
+		strioctl.ic_cmd = SIOCGIFFLAGS;
+		strioctl.ic_dp  = (char *)&ifreq;
+		strioctl.ic_len = sizeof(struct ifreq);
+		if (ioctl(fd, I_STR, &strioctl) != 0) {
+			continue;
+		}
+		
+		if (!(ifreq.ifr_flags & IFF_UP)) {
+			continue;
+		}
+
+		strioctl.ic_cmd = SIOCGIFADDR;
+		strioctl.ic_dp  = (char *)&ifreq;
+		strioctl.ic_len = sizeof(struct ifreq);
+		if (ioctl(fd, I_STR, &strioctl) != 0) {
+			continue;
+		}
+
+		ipaddr = (*(struct sockaddr_in *) &ifreq.ifr_addr).sin_addr;
+		iname = ifreq.ifr_name;
+
+		strioctl.ic_cmd = SIOCGIFNETMASK;
+		strioctl.ic_dp  = (char *)&ifreq;
+		strioctl.ic_len = sizeof(struct ifreq);
+		if (ioctl(fd, I_STR, &strioctl) != 0) {
+			continue;
+		}
+
+		nmask = ((struct sockaddr_in *)&ifreq.ifr_addr)->sin_addr;
+
+		strncpy(ifaces[total].name, iname, sizeof(ifaces[total].name)-1);
+		ifaces[total].name[sizeof(ifaces[total].name)-1] = 0;
+		ifaces[total].ip = ipaddr;
+		ifaces[total].netmask = nmask;
+
+		total++;
+	}
+
+	close(fd);
+
+	return total;
+}
+
+#elif HAVE_IFACE_AIX
+
+/****************************************************************************
+this one is for AIX (tested on 4.2)
+****************************************************************************/
+static int _get_interfaces(struct iface_struct *ifaces, int max_interfaces)
+{
+	char buff[8192];
+	int fd, i;
+	struct ifconf ifc;
+	struct ifreq *ifr=NULL;
+	struct in_addr ipaddr;
+	struct in_addr nmask;
+	char *iname;
+	int total = 0;
+
+	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
+		return -1;
+	}
+
+
+	ifc.ifc_len = sizeof(buff);
+	ifc.ifc_buf = buff;
+
+	if (ioctl(fd, SIOCGIFCONF, &ifc) != 0) {
+		close(fd);
+		return -1;
+	}
+
+	ifr = ifc.ifc_req;
+
+	/* Loop through interfaces */
+	i = ifc.ifc_len;
+
+	while (i > 0 && total < max_interfaces) {
+		uint_t inc;
+
+		inc = ifr->ifr_addr.sa_len;
+
+		if (ioctl(fd, SIOCGIFADDR, ifr) != 0) {
+			goto next;
+		}
+
+		ipaddr = (*(struct sockaddr_in *) &ifr->ifr_addr).sin_addr;
+		iname = ifr->ifr_name;
+
+		if (ioctl(fd, SIOCGIFFLAGS, ifr) != 0) {
+			goto next;
+		}
+
+		if (!(ifr->ifr_flags & IFF_UP)) {
+			goto next;
+		}
+
+		if (ioctl(fd, SIOCGIFNETMASK, ifr) != 0) {
+			goto next;
+		}
+
+		nmask = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
+
+		strncpy(ifaces[total].name, iname, sizeof(ifaces[total].name)-1);
+		ifaces[total].name[sizeof(ifaces[total].name)-1] = 0;
+		ifaces[total].ip = ipaddr;
+		ifaces[total].netmask = nmask;
+
+		total++;
+
+	next:
+		/*
+		 * Patch from Archie Cobbs (archie@whistle.com).  The
+		 * addresses in the SIOCGIFCONF interface list have a
+		 * minimum size. Usually this doesn't matter, but if
+		 * your machine has tunnel interfaces, etc. that have
+		 * a zero length "link address", this does matter.  */
+
+		if (inc < sizeof(ifr->ifr_addr))
+			inc = sizeof(ifr->ifr_addr);
+		inc += IFNAMSIZ;
+
+		ifr = (struct ifreq*) (((char*) ifr) + inc);
+		i -= inc;
+	}
+  
+
+	close(fd);
+	return total;
+}
+
+#else /* a dummy version */
+static int _get_interfaces(struct iface_struct *ifaces, int max_interfaces)
+{
+	return -1;
+}
+#endif
+
+
+static int iface_comp(struct iface_struct *i1, struct iface_struct *i2)
+{
+	int r;
+	r = strcmp(i1->name, i2->name);
+	if (r) return r;
+	r = ntohl(i1->ip.s_addr) - ntohl(i2->ip.s_addr);
+	if (r) return r;
+	r = ntohl(i1->netmask.s_addr) - ntohl(i2->netmask.s_addr);
+	return r;
+}
+
+/* this wrapper is used to remove duplicates from the interface list generated
+   above */
+int get_interfaces(struct iface_struct *ifaces, int max_interfaces)
+{
+	int total, i, j;
+
+	total = _get_interfaces(ifaces, max_interfaces);
+	if (total <= 0) return total;
+
+	/* now we need to remove duplicates */
+	qsort(ifaces, total, sizeof(ifaces[0]), QSORT_CAST iface_comp);
+
+	for (i=1;i<total;) {
+		if (iface_comp(&ifaces[i-1], &ifaces[i]) == 0) {
+			for (j=i-1;j<total-1;j++) {
+				ifaces[j] = ifaces[j+1];
+			}
+			total--;
+		} else {
+			i++;
+		}
+	}
+
+	return total;
+}
+
+
+#ifdef AUTOCONF_TEST
+/* this is the autoconf driver to test get_interfaces() */
+
+ int main()
+{
+	struct iface_struct ifaces[MAX_INTERFACES];
+	int total = get_interfaces(ifaces, MAX_INTERFACES);
+	int i;
+
+	printf("got %d interfaces:\n", total);
+	if (total <= 0) exit(1);
+
+	for (i=0;i<total;i++) {
+		printf("%-10s ", ifaces[i].name);
+		printf("IP=%s ", inet_ntoa(ifaces[i].ip));
+		printf("NETMASK=%s\n", inet_ntoa(ifaces[i].netmask));
+	}
+	return 0;
+}
+#endif
diff --git a/source4/lib/socket/netif.h b/source4/lib/socket/netif.h
new file mode 100644
index 0000000000..ad7c31eb9e
--- /dev/null
+++ b/source4/lib/socket/netif.h
@@ -0,0 +1,33 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   structures for lib/netif/
+
+   Copyright (C) Andrew Tridgell 2004
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+struct iface_struct {
+	char name[16];
+	struct in_addr ip;
+	struct in_addr netmask;
+};
+
+#define MAX_INTERFACES 128
+
+#ifndef AUTOCONF_TEST
+#include "lib/socket/netif_proto.h"
+#endif