freebsd-nq/libntp/netof.c
Ollivier Robert 2b45e011ca Virgin import of ntpd 4.2.6p5.
When the series of commits is complete, things like
https://cert.litnet.lt/en/docs/ntp-distributed-reflection-dos-attacks
should be fixed.

PR:		bin/148836 (except that we import a newer version)
Asked by:	Too many
MFC after:	2 weeks
2013-12-04 21:33:17 +00:00

55 lines
1.2 KiB
C

/*
* netof - return the net address part of an ip address in a sockaddr_storage structure
* (zero out host part)
*/
#include <stdio.h>
#include <syslog.h>
#include "ntp_fp.h"
#include "ntp_net.h"
#include "ntp_stdlib.h"
#include "ntp.h"
sockaddr_u *
netof(
sockaddr_u *hostaddr
)
{
static sockaddr_u netofbuf[8];
static int next_netofbuf;
u_int32 netnum;
sockaddr_u * netaddr;
netaddr = &netofbuf[next_netofbuf];
next_netofbuf = (next_netofbuf + 1) % COUNTOF(netofbuf);
memcpy(netaddr, hostaddr, sizeof(*netaddr));
if (IS_IPV4(netaddr)) {
netnum = SRCADR(netaddr);
/*
* We live in a modern CIDR world where the basement nets, which
* used to be class A, are now probably associated with each
* host address. So, for class-A nets, all bits are significant.
*/
if (IN_CLASSC(netnum))
netnum &= IN_CLASSC_NET;
else if (IN_CLASSB(netnum))
netnum &= IN_CLASSB_NET;
SET_ADDR4(netaddr, netnum);
} else if (IS_IPV6(netaddr))
/* assume the typical /64 subnet size */
memset(&NSRCADR6(netaddr)[8], 0, 8);
#ifdef DEBUG
else {
msyslog(LOG_ERR, "netof unknown AF %d", AF(netaddr));
exit(1);
}
#endif
return netaddr;
}