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/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
/* NetworkManager -- Network link manager
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Copyright (C) 2013 Red Hat, Inc.
*/
#include <config.h>
#include <string.h>
#include <arpa/inet.h>
#include "nm-dnsmasq-utils.h"
#include "nm-platform.h"
#include "nm-utils.h"
gboolean
nm_dnsmasq_utils_get_range (const NMPlatformIP4Address *addr,
char *out_first,
char *out_last,
char **out_error_desc)
{
guint32 host = addr->address;
guint32 prefix = addr->plen;
guint32 netmask = nm_utils_ip4_prefix_to_netmask (prefix);
guint32 first, last, reserved;
g_return_val_if_fail (out_first != NULL, FALSE);
g_return_val_if_fail (out_last != NULL, FALSE);
if (prefix > 30) {
if (out_error_desc)
*out_error_desc = g_strdup_printf ("Address prefix %d is too small for DHCP.", prefix);
return FALSE;
}
/* Find the first available address *after* the local machine's IP */
first = (host & netmask) + htonl (1);
/* Shortcut: allow a max of 253 addresses; the - htonl(1) here is to assure
* that we don't set 'last' to the broadcast address of the network. */
if (prefix < 24)
last = (host | ~nm_utils_ip4_prefix_to_netmask (24)) - htonl (1);
else
last = (host | ~netmask) - htonl(1);
/* Figure out which range (either above the host address or below it)
* has more addresses. Reserve some addresses for static IPs.
*/
if (ntohl (host) - ntohl (first) > ntohl (last) - ntohl (host)) {
/* Range below the host's IP address */
reserved = (guint32) ((ntohl (host) - ntohl (first)) / 10);
last = host - htonl (MIN (reserved, 8)) - htonl (1);
} else {
/* Range above host's IP address */
reserved = (guint32) ((ntohl (last) - ntohl (host)) / 10);
first = host + htonl (MIN (reserved, 8)) + htonl (1);
}
nm_utils_inet4_ntop (first, out_first);
nm_utils_inet4_ntop (last, out_last);
return TRUE;
}
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