1 /* 2 * Copyright (c) 1983 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #if defined(LIBC_SCCS) && !defined(lint) 19 static char sccsid[] = "@(#)inet_netof.c 5.5 (Berkeley) 06/27/88"; 20 #endif /* LIBC_SCCS and not lint */ 21 22 #include <sys/types.h> 23 #include <netinet/in.h> 24 25 /* 26 * Return the network number from an internet 27 * address; handles class a/b/c network #'s. 28 */ 29 u_long 30 inet_netof(in) 31 struct in_addr in; 32 { 33 register u_long i = ntohl(in.s_addr); 34 35 if (IN_CLASSA(i)) 36 return (((i)&IN_CLASSA_NET) >> IN_CLASSA_NSHIFT); 37 else if (IN_CLASSB(i)) 38 return (((i)&IN_CLASSB_NET) >> IN_CLASSB_NSHIFT); 39 else 40 return (((i)&IN_CLASSC_NET) >> IN_CLASSC_NSHIFT); 41 } 42