1: /*
    2:  * Copyright (c) 1983, 1993
    3:  *      The Regents of the University of California.  All rights reserved.
    4:  *
    5:  * Redistribution and use in source and binary forms, with or without
    6:  * modification, are permitted provided that the following conditions
    7:  * are met:
    8:  * 1. Redistributions of source code must retain the above copyright
    9:  *    notice, this list of conditions and the following disclaimer.
   10:  * 2. Redistributions in binary form must reproduce the above copyright
   11:  *    notice, this list of conditions and the following disclaimer in the
   12:  *    documentation and/or other materials provided with the distribution.
   13:  * 4. Neither the name of the University nor the names of its contributors
   14:  *    may be used to endorse or promote products derived from this software
   15:  *    without specific prior written permission.
   16:  *
   17:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27:  * SUCH DAMAGE.
   28:  */
   29: 
   30: #if defined(LIBC_SCCS) && !defined(lint)
   31: static char sccsid[] = "@(#)inet_netof.c        8.1 (Berkeley) 6/4/93";
   32: #endif /* LIBC_SCCS and not lint */
   33: 
   34: #include <sys/param.h>
   35: #include <netinet/in.h>
   36: #include <arpa/inet.h>
   37: 
   38: /*
   39:  * Return the network number from an internet
   40:  * address; handles class a/b/c network #'s.
   41:  */
   42: in_addr_t
   43: inet_netof(in)
   44:         struct in_addr in;
   45: {
   46:         register u_int32_t i = ntohl(in.s_addr);
   47: 
   48:         if (IN_CLASSA(i))
   49:                 return (((i)&IN_CLASSA_NET) >> IN_CLASSA_NSHIFT);
   50:         else if (IN_CLASSB(i))
   51:                 return (((i)&IN_CLASSB_NET) >> IN_CLASSB_NSHIFT);
   52:         else
   53:                 return (((i)&IN_CLASSC_NET) >> IN_CLASSC_NSHIFT);
   54: }
   55: libc_hidden_def (inet_netof)