--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/util-src/net.c	Tue Jun 18 09:04:44 2013 +0100
@@ -0,0 +1,107 @@
+/* Prosody IM
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+-- Copyright (C) 2012 Paul Aurich
+-- Copyright (C) 2013 Matthew Wild
+-- Copyright (C) 2013 Florian Zeitz
+--
+*/
+
+#include <stddef.h>
+#include <string.h>
+#include <errno.h>
+
+#ifndef _WIN32
+  #include <sys/ioctl.h>
+  #include <sys/types.h>
+  #include <sys/socket.h>
+  #include <net/if.h>
+  #include <ifaddrs.h>
+  #include <arpa/inet.h>
+#endif
+
+#include <lua.h>
+#include <lauxlib.h>
+
+/* Enumerate all locally configured IP addresses */
+
+const char * const type_strings[] = {
+	"both",
+	"ipv4",
+	"ipv6",
+	NULL
+};
+
+static int lc_local_addresses(lua_State *L)
+{
+	/* Link-local IPv4 addresses; see RFC 3927 and RFC 5735 */
+	const long ip4_linklocal = htonl(0xa9fe0000); /* 169.254.0.0 */
+	const long ip4_mask      = htonl(0xffff0000);
+#ifndef _WIN32
+	struct ifaddrs *addr = NULL, *a;
+	int n = 1;
+#endif
+	int type = luaL_checkoption(L, 1, "both", type_strings);
+	const char link_local = lua_toboolean(L, 2); /* defaults to 0 (false) */
+	const char ipv4 = (type == 0 || type == 1);
+	const char ipv6 = (type == 0 || type == 2);
+
+#ifndef _WIN32
+	if (getifaddrs(&addr) < 0) {
+		lua_pushnil(L);
+		lua_pushfstring(L, "getifaddrs failed (%d): %s", errno,
+		strerror(errno));
+		return 2;
+	}
+
+	lua_newtable(L);
+
+	for (a = addr; a; a = a->ifa_next) {
+		int family;
+		char ipaddr[INET6_ADDRSTRLEN];
+		const char *tmp = NULL;
+
+		if (a->ifa_addr == NULL || a->ifa_flags & IFF_LOOPBACK)
+			continue;
+
+		family = a->ifa_addr->sa_family;
+
+		if (ipv4 && family == AF_INET) {
+			struct sockaddr_in *sa = (struct sockaddr_in *)a->ifa_addr;
+			if (!link_local &&((sa->sin_addr.s_addr & ip4_mask) == ip4_linklocal))
+				continue;
+			tmp = inet_ntop(family, &sa->sin_addr, ipaddr, sizeof(ipaddr));
+		} else if (ipv6 && family == AF_INET6) {
+			struct sockaddr_in6 *sa = (struct sockaddr_in6 *)a->ifa_addr;
+			if (!link_local && IN6_IS_ADDR_LINKLOCAL(&sa->sin6_addr))
+				continue;
+			if (IN6_IS_ADDR_V4MAPPED(&sa->sin6_addr) || IN6_IS_ADDR_V4COMPAT(&sa->sin6_addr))
+				continue;
+			tmp = inet_ntop(family, &sa->sin6_addr, ipaddr, sizeof(ipaddr));
+		}
+
+		if (tmp != NULL) {
+			lua_pushstring(L, tmp);
+			lua_rawseti(L, -2, n++);
+		}
+		/* TODO: Error reporting? */
+	}
+
+	freeifaddrs(addr);
+
+	return 1;
+#endif
+}
+
+int luaopen_util_net(lua_State* L)
+{
+	luaL_Reg exports[] = {
+		{ "local_addresses", lc_local_addresses },
+		{ NULL, NULL }
+	};
+
+	luaL_register(L, "net",  exports);
+	return 1;
+}