diff --git a/freebsd-userspace/Makefile b/freebsd-userspace/Makefile
index df5e4f2f..7b31a3fc 100644
--- a/freebsd-userspace/Makefile
+++ b/freebsd-userspace/Makefile
@@ -75,6 +75,7 @@ C_FILES += lib/libc/nameser/ns_samedomain.c
 C_FILES += lib/libc/nameser/ns_ttl.c
 C_FILES += lib/libc/net/if_indextoname.c
 C_FILES += lib/libc/net/if_nameindex.c
+C_FILES += lib/libc/net/if_nametoindex.c
 C_FILES += lib/libc/net/linkaddr.c
 C_FILES += lib/libc/net/map_v4v6.c
 C_FILES += lib/libc/net/name6.c
diff --git a/freebsd-userspace/lib/libc/net/if_nametoindex.c b/freebsd-userspace/lib/libc/net/if_nametoindex.c
new file mode 100644
index 00000000..a278ca07
--- /dev/null
+++ b/freebsd-userspace/lib/libc/net/if_nametoindex.c
@@ -0,0 +1,102 @@
+/*	$KAME: if_nametoindex.c,v 1.6 2000/11/24 08:18:54 itojun Exp $	*/
+
+/*-
+ * Copyright (c) 1997, 2000
+ *	Berkeley Software Design, Inc.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	BSDI Id: if_nametoindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "namespace.h"
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/sockio.h>
+#include <net/if.h>
+#include <net/if_dl.h>
+#include <ifaddrs.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include "un-namespace.h"
+#ifdef __rtems__
+#include <freebsd/sys/sockio.h>
+#endif
+
+/*
+ * From RFC 2553:
+ *
+ * 4.1 Name-to-Index
+ *
+ *
+ *    The first function maps an interface name into its corresponding
+ *    index.
+ *
+ *       #include <net/if.h>
+ *
+ *       unsigned int  if_nametoindex(const char *ifname);
+ *
+ *    If the specified interface name does not exist, the return value is
+ *    0, and errno is set to ENXIO.  If there was a system error (such as
+ *    running out of memory), the return value is 0 and errno is set to the
+ *    proper value (e.g., ENOMEM).
+ */
+
+unsigned int
+if_nametoindex(const char *ifname)
+{
+	int s;
+	struct ifreq ifr;
+	struct ifaddrs *ifaddrs, *ifa;
+	unsigned int ni;
+
+	s = _socket(AF_INET, SOCK_DGRAM, 0);
+	if (s != -1) {
+		strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+		if (_ioctl(s, SIOCGIFINDEX, &ifr) != -1) {
+			_close(s);
+			return (ifr.ifr_index);
+		}
+		_close(s);
+	}
+
+	if (getifaddrs(&ifaddrs) < 0)
+		return(0);
+
+	ni = 0;
+
+	for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
+		if (ifa->ifa_addr &&
+		    ifa->ifa_addr->sa_family == AF_LINK &&
+		    strcmp(ifa->ifa_name, ifname) == 0) {
+			ni = ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index;
+			break;
+		}
+	}
+
+	freeifaddrs(ifaddrs);
+	if (!ni)
+		errno = ENXIO;
+	return(ni);
+}