1 /* $NetBSD: netof.c,v 1.5 2020/05/25 20:47:24 christos Exp $ */ 2 3 /* 4 * netof - return the net address part of an ip address in a sockaddr_storage structure 5 * (zero out host part) 6 */ 7 #include <config.h> 8 #include <stdio.h> 9 #include <syslog.h> 10 11 #include "ntp_fp.h" 12 #include "ntp_net.h" 13 #include "ntp_stdlib.h" 14 #include "ntp.h" 15 16 sockaddr_u * 17 netof( 18 sockaddr_u *hostaddr 19 ) 20 { 21 static sockaddr_u netofbuf[8]; 22 static int next_netofbuf; 23 u_int32 netnum; 24 sockaddr_u * netaddr; 25 26 netaddr = &netofbuf[next_netofbuf]; 27 next_netofbuf = (next_netofbuf + 1) % COUNTOF(netofbuf); 28 29 memcpy(netaddr, hostaddr, sizeof(*netaddr)); 30 31 if (IS_IPV4(netaddr)) { 32 netnum = SRCADR(netaddr); 33 34 /* 35 * We live in a modern CIDR world where the basement nets, which 36 * used to be class A, are now probably associated with each 37 * host address. So, for class-A nets, all bits are significant. 38 */ 39 if (IN_CLASSC(netnum)) 40 netnum &= IN_CLASSC_NET; 41 else if (IN_CLASSB(netnum)) 42 netnum &= IN_CLASSB_NET; 43 44 SET_ADDR4(netaddr, netnum); 45 46 } else if (IS_IPV6(netaddr)) 47 /* assume the typical /64 subnet size */ 48 zero_mem(&NSRCADR6(netaddr)[8], 8); 49 #ifdef DEBUG 50 else { 51 msyslog(LOG_ERR, "netof unknown AF %d", AF(netaddr)); 52 exit(1); 53 } 54 #endif 55 56 return netaddr; 57 } 58