xref: /csrg-svn/sbin/routed/inet.c (revision 33489)
121994Sdist /*
221994Sdist  * Copyright (c) 1983 Regents of the University of California.
3*33489Sbostic  * All rights reserved.
4*33489Sbostic  *
5*33489Sbostic  * Redistribution and use in source and binary forms are permitted
6*33489Sbostic  * provided that this notice is preserved and that due credit is given
7*33489Sbostic  * to the University of California at Berkeley. The name of the University
8*33489Sbostic  * may not be used to endorse or promote products derived from this
9*33489Sbostic  * software without specific prior written permission. This software
10*33489Sbostic  * is provided ``as is'' without express or implied warranty.
1121994Sdist  */
1221994Sdist 
1316395Skarels #ifndef lint
14*33489Sbostic static char sccsid[] = "@(#)inet.c	5.6 (Berkeley) 02/16/88";
15*33489Sbostic #endif /* not lint */
1621994Sdist 
1716395Skarels /*
1816395Skarels  * Temporarily, copy these routines from the kernel,
1916395Skarels  * as we need to know about subnets.
2016395Skarels  */
2116395Skarels #include "defs.h"
2216395Skarels 
2321846Skarels extern struct interface *ifnet;
2421846Skarels 
2516395Skarels /*
2621846Skarels  * Formulate an Internet address from network + host.
2716395Skarels  */
2816395Skarels struct in_addr
2921846Skarels inet_makeaddr(net, host)
3021846Skarels 	u_long net, host;
3116395Skarels {
3221846Skarels 	register struct interface *ifp;
3321846Skarels 	register u_long mask;
3416395Skarels 	u_long addr;
3516395Skarels 
3621846Skarels 	if (IN_CLASSA(net))
3721846Skarels 		mask = IN_CLASSA_HOST;
3821846Skarels 	else if (IN_CLASSB(net))
3921846Skarels 		mask = IN_CLASSB_HOST;
4016395Skarels 	else
4121846Skarels 		mask = IN_CLASSC_HOST;
4221846Skarels 	for (ifp = ifnet; ifp; ifp = ifp->int_next)
4321846Skarels 		if ((ifp->int_netmask & net) == ifp->int_net) {
4421846Skarels 			mask = ~ifp->int_subnetmask;
4521846Skarels 			break;
4621846Skarels 		}
4721846Skarels 	addr = net | (host & mask);
4816395Skarels 	addr = htonl(addr);
4916395Skarels 	return (*(struct in_addr *)&addr);
5016395Skarels }
5116395Skarels 
5216395Skarels /*
5316395Skarels  * Return the network number from an internet address.
5416395Skarels  */
5516395Skarels inet_netof(in)
5616395Skarels 	struct in_addr in;
5716395Skarels {
5816395Skarels 	register u_long i = ntohl(in.s_addr);
5921846Skarels 	register u_long net;
6016429Skarels 	register struct interface *ifp;
6116395Skarels 
6221846Skarels 	if (IN_CLASSA(i))
6321846Skarels 		net = i & IN_CLASSA_NET;
6421846Skarels 	else if (IN_CLASSB(i))
6521846Skarels 		net = i & IN_CLASSB_NET;
6621846Skarels 	else
6721846Skarels 		net = i & IN_CLASSC_NET;
6816429Skarels 
6916429Skarels 	/*
7021846Skarels 	 * Check whether network is a subnet;
7116429Skarels 	 * if so, return subnet number.
7216429Skarels 	 */
7321846Skarels 	for (ifp = ifnet; ifp; ifp = ifp->int_next)
7421846Skarels 		if ((ifp->int_netmask & net) == ifp->int_net)
7521846Skarels 			return (i & ifp->int_subnetmask);
7616429Skarels 	return (net);
7716395Skarels }
7816395Skarels 
7916395Skarels /*
8016395Skarels  * Return the host portion of an internet address.
8116395Skarels  */
8216395Skarels inet_lnaof(in)
8316395Skarels 	struct in_addr in;
8416395Skarels {
8516395Skarels 	register u_long i = ntohl(in.s_addr);
8621846Skarels 	register u_long net, host;
8716429Skarels 	register struct interface *ifp;
8816395Skarels 
8916395Skarels 	if (IN_CLASSA(i)) {
9021846Skarels 		net = i & IN_CLASSA_NET;
9121846Skarels 		host = i & IN_CLASSA_HOST;
9216395Skarels 	} else if (IN_CLASSB(i)) {
9321846Skarels 		net = i & IN_CLASSB_NET;
9421846Skarels 		host = i & IN_CLASSB_HOST;
9516395Skarels 	} else {
9621846Skarels 		net = i & IN_CLASSC_NET;
9721846Skarels 		host = i & IN_CLASSC_HOST;
9816395Skarels 	}
9916395Skarels 
10016429Skarels 	/*
10121846Skarels 	 * Check whether network is a subnet;
10216429Skarels 	 * if so, use the modified interpretation of `host'.
10316429Skarels 	 */
10421846Skarels 	for (ifp = ifnet; ifp; ifp = ifp->int_next)
10521846Skarels 		if ((ifp->int_netmask & net) == ifp->int_net)
10621846Skarels 			return (host &~ ifp->int_subnetmask);
10716429Skarels 	return (host);
10816395Skarels }
10927231Skarels 
11027231Skarels /*
11127231Skarels  * Return RTF_HOST if the address is
11227231Skarels  * for an Internet host, RTF_SUBNET for a subnet,
11327231Skarels  * 0 for a network.
11427231Skarels  */
11527231Skarels inet_rtflags(sin)
11627231Skarels 	struct sockaddr_in *sin;
11727231Skarels {
11827231Skarels 	register u_long i = ntohl(sin->sin_addr.s_addr);
11927231Skarels 	register u_long net, host;
12027231Skarels 	register struct interface *ifp;
12127231Skarels 
12227231Skarels 	if (IN_CLASSA(i)) {
12327231Skarels 		net = i & IN_CLASSA_NET;
12427231Skarels 		host = i & IN_CLASSA_HOST;
12527231Skarels 	} else if (IN_CLASSB(i)) {
12627231Skarels 		net = i & IN_CLASSB_NET;
12727231Skarels 		host = i & IN_CLASSB_HOST;
12827231Skarels 	} else {
12927231Skarels 		net = i & IN_CLASSC_NET;
13027231Skarels 		host = i & IN_CLASSC_HOST;
13127231Skarels 	}
13227231Skarels 
13327231Skarels 	/*
13427231Skarels 	 * Check whether this network is subnetted;
13527231Skarels 	 * if so, check whether this is a subnet or a host.
13627231Skarels 	 */
13727231Skarels 	for (ifp = ifnet; ifp; ifp = ifp->int_next)
13827231Skarels 		if (net == ifp->int_net) {
13928994Skarels 			if (host &~ ifp->int_subnetmask)
14028994Skarels 				return (RTF_HOST);
14128994Skarels 			else if (ifp->int_subnetmask != ifp->int_netmask)
14227231Skarels 				return (RTF_SUBNET);
14327231Skarels 			else
14428994Skarels 				return (0);		/* network */
14527231Skarels 		}
14628994Skarels 	if (host == 0)
14728994Skarels 		return (0);	/* network */
14828994Skarels 	else
14928994Skarels 		return (RTF_HOST);
15027231Skarels }
15127231Skarels 
15227231Skarels /*
15331220Skarels  * Return true if a route to subnet/host of route rt should be sent to dst.
15431220Skarels  * Send it only if dst is on the same logical network if not "internal",
15531220Skarels  * otherwise only if the route is the "internal" route for the logical net.
15627231Skarels  */
15731220Skarels inet_sendroute(rt, dst)
15828906Skarels 	struct rt_entry *rt;
15928906Skarels 	struct sockaddr_in *dst;
16027231Skarels {
16128906Skarels 	register u_long r =
16228906Skarels 	    ntohl(((struct sockaddr_in *)&rt->rt_dst)->sin_addr.s_addr);
16327231Skarels 	register u_long d = ntohl(dst->sin_addr.s_addr);
16427231Skarels 
16528906Skarels 	if (IN_CLASSA(r)) {
16628906Skarels 		if ((r & IN_CLASSA_NET) == (d & IN_CLASSA_NET)) {
16728906Skarels 			if ((r & IN_CLASSA_HOST) == 0)
16828906Skarels 				return ((rt->rt_state & RTS_INTERNAL) == 0);
16927231Skarels 			return (1);
17028906Skarels 		}
17128994Skarels 		if (r & IN_CLASSA_HOST)
17228994Skarels 			return (0);
17328994Skarels 		return ((rt->rt_state & RTS_INTERNAL) != 0);
17428906Skarels 	} else if (IN_CLASSB(r)) {
17528906Skarels 		if ((r & IN_CLASSB_NET) == (d & IN_CLASSB_NET)) {
17628906Skarels 			if ((r & IN_CLASSB_HOST) == 0)
17728906Skarels 				return ((rt->rt_state & RTS_INTERNAL) == 0);
17827231Skarels 			return (1);
17928906Skarels 		}
18028994Skarels 		if (r & IN_CLASSB_HOST)
18128994Skarels 			return (0);
18228994Skarels 		return ((rt->rt_state & RTS_INTERNAL) != 0);
18327231Skarels 	} else {
18428906Skarels 		if ((r & IN_CLASSC_NET) == (d & IN_CLASSC_NET)) {
18528906Skarels 			if ((r & IN_CLASSC_HOST) == 0)
18628906Skarels 				return ((rt->rt_state & RTS_INTERNAL) == 0);
18727231Skarels 			return (1);
18828906Skarels 		}
18928994Skarels 		if (r & IN_CLASSC_HOST)
19028994Skarels 			return (0);
19128994Skarels 		return ((rt->rt_state & RTS_INTERNAL) != 0);
19227231Skarels 	}
19327231Skarels }
194