1 /*
2 * netof - return the net address part of an ip address in a sockaddr_storage structure
3 * (zero out host part)
4 */
5 #include <config.h>
6 #include <stdio.h>
7 #include <syslog.h>
8
9 #include "ntp_fp.h"
10 #include "ntp_net.h"
11 #include "ntp_stdlib.h"
12 #include "ntp.h"
13
14 sockaddr_u *
netof(sockaddr_u * hostaddr)15 netof(
16 sockaddr_u *hostaddr
17 )
18 {
19 static sockaddr_u netofbuf[8];
20 static int next_netofbuf;
21 u_int32 netnum;
22 sockaddr_u * netaddr;
23
24 netaddr = &netofbuf[next_netofbuf];
25 next_netofbuf = (next_netofbuf + 1) % COUNTOF(netofbuf);
26
27 memcpy(netaddr, hostaddr, sizeof(*netaddr));
28
29 if (IS_IPV4(netaddr)) {
30 netnum = SRCADR(netaddr);
31
32 /*
33 * We live in a modern CIDR world where the basement nets, which
34 * used to be class A, are now probably associated with each
35 * host address. So, for class-A nets, all bits are significant.
36 */
37 if (IN_CLASSC(netnum))
38 netnum &= IN_CLASSC_NET;
39 else if (IN_CLASSB(netnum))
40 netnum &= IN_CLASSB_NET;
41
42 SET_ADDR4(netaddr, netnum);
43
44 } else if (IS_IPV6(netaddr))
45 /* assume the typical /64 subnet size */
46 zero_mem(&NSRCADR6(netaddr)[8], 8);
47 #ifdef DEBUG
48 else {
49 msyslog(LOG_ERR, "netof unknown AF %d", AF(netaddr));
50 exit(1);
51 }
52 #endif
53
54 return netaddr;
55 }
56