1 /* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #if defined(LIBC_SCCS) && !defined(lint) 9 static char sccsid[] = "@(#)inet_netof.c 8.1 (Berkeley) 06/04/93"; 10 #endif /* LIBC_SCCS and not lint */ 11 12 #include <sys/param.h> 13 #include <netinet/in.h> 14 #include <arpa/inet.h> 15 16 /* 17 * Return the network number from an internet 18 * address; handles class a/b/c network #'s. 19 */ 20 u_long 21 inet_netof(in) 22 struct in_addr in; 23 { 24 register u_long i = ntohl(in.s_addr); 25 26 if (IN_CLASSA(i)) 27 return (((i)&IN_CLASSA_NET) >> IN_CLASSA_NSHIFT); 28 else if (IN_CLASSB(i)) 29 return (((i)&IN_CLASSB_NET) >> IN_CLASSB_NSHIFT); 30 else 31 return (((i)&IN_CLASSC_NET) >> IN_CLASSC_NSHIFT); 32 } 33