1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
/*
*
* 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;
}
|
