freebsd-dev/contrib/ntp/libntp/netof.c
2004-07-20 15:01:56 +00:00

49 lines
1.3 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 "ntp_fp.h"
#include "ntp_stdlib.h"
#include "ntp.h"
#define NUM_NETOF_BUFS 10
static struct sockaddr_storage ssbuf[NUM_NETOF_BUFS];
static int next_ssbuf = 0;
struct sockaddr_storage*
netof(
struct sockaddr_storage* hostaddr
)
{
register u_int32 netnum;
struct sockaddr_storage *netaddr;
netaddr = &ssbuf[next_ssbuf++];
if (next_ssbuf == NUM_NETOF_BUFS)
next_ssbuf = 0;
memcpy(netaddr, hostaddr, sizeof(struct sockaddr_storage));
if(netaddr->ss_family == AF_INET) {
netnum = ((struct sockaddr_in*)netaddr)->sin_addr.s_addr;
/*
* 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;
((struct sockaddr_in*)netaddr)->sin_addr.s_addr = netnum;
}
else if(netaddr->ss_family == AF_INET6) {
/* Here we put 0 at the local link address so we get net address */
memset(&((struct sockaddr_in6*)netaddr)->sin6_addr.s6_addr[8], 0, 8*sizeof(u_char));
}
return netaddr;
}