--- /dev/null
+/*
+ *
+ * Connection Manager
+ *
+ * Copyright (C) 2007-2009 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <arpa/inet.h>
+
+static unsigned char netmask2prefixlen(const char *netmask)
+{
+ unsigned char bits = 0;
+ in_addr_t mask = inet_network(netmask);
+ in_addr_t host = ~mask;
+
+ /* a valid netmask must be 2^n - 1 */
+ if ((host & (host + 1)) != 0)
+ return -1;
+
+ for (; mask; mask <<= 1)
+ ++bits;
+
+ return bits;
+}
+
+int main(int argc, char *argv[])
+{
+ const char *masks[] = { "255.255.255.255", "255.255.255.0",
+ "255.255.0.0", "255.0.0.0" };
+ struct in_addr addr;
+ int i, len;
+
+ for (i = 0; i < 4; i++) {
+ printf("subnet %-16s prefixlen %u\n", masks[i],
+ netmask2prefixlen(masks[i]));
+ }
+
+ printf("\n");
+
+ for (i = 0; i < 4; i++) {
+ len = (i + 1) * 8;
+ addr.s_addr = htonl(~(0xfffffffflu >> len));
+ printf("prefixlen %-2u netmask %s\n", len, inet_ntoa(addr));
+ }
+
+ return 0;
+}