in.c

很好的一个嵌入式linux平台下的bootloader

/* $Id: in.c,v 1.2 1996/01/16 14:22:07 chris Exp $ */
/*
 * Copyright (c) 1982, 1986, 1991 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)in.c	7.17 (Berkeley) 4/20/91
 */

#include "param.h"
#include "ioctl.h"
#include "mbuf.h"
#include "socket.h"
#include "socketvar.h"
#include "in_systm.h"
#include "net/if.h"
#include "net/route.h"
#include "net/af.h"
#include "in.h"
#include "in_var.h"

#ifdef INET
/*
 * Formulate an Internet address from network + host.
 */
struct in_addr
in_makeaddr(net, host)
	u_long net, host;
{
	register struct in_ifaddr *ia;
	register u_long mask;
	u_long addr;

	if (IN_CLASSA(net))
		mask = IN_CLASSA_HOST;
	else if (IN_CLASSB(net))
		mask = IN_CLASSB_HOST;
	else
		mask = IN_CLASSC_HOST;
	for (ia = in_ifaddr; ia; ia = ia->ia_next)
		if ((ia->ia_netmask & net) == ia->ia_net) {
			mask = ~ia->ia_subnetmask;
			break;
		}
	addr = htonl(net | (host & mask));
	return (*(struct in_addr *)&addr);
}

/*
 * Return the network number from an internet address.
 */
u_long
in_netof(in)
	struct in_addr in;
{
	register u_long i = ntohl(in.s_addr);
	register u_long net;
	register struct in_ifaddr *ia;

	if (IN_CLASSA(i))
		net = i & IN_CLASSA_NET;
	else if (IN_CLASSB(i))
		net = i & IN_CLASSB_NET;
	else if (IN_CLASSC(i))
		net = i & IN_CLASSC_NET;
	else
		return (0);

	/*
	 * Check whether network is a subnet;
	 * if so, return subnet number.
	 */
	for (ia = in_ifaddr; ia; ia = ia->ia_next)
		if (net == ia->ia_net)
			return (i & ia->ia_subnetmask);
	return (net);
}

/*
 * Compute and save network mask as sockaddr from an internet address.
 */
in_sockmaskof(in, sockmask)
	struct in_addr in;
	register struct sockaddr_in *sockmask;
{
	register u_long net;
	register u_long mask;
    {
	register u_long i = ntohl(in.s_addr);

	if (i == 0)
		net = 0, mask = 0;
	else if (IN_CLASSA(i))
		net = i & IN_CLASSA_NET, mask = IN_CLASSA_NET;
	else if (IN_CLASSB(i))
		net = i & IN_CLASSB_NET, mask = IN_CLASSB_NET;
	else if (IN_CLASSC(i))
		net = i & IN_CLASSC_NET, mask = IN_CLASSC_NET;
	else
		net = i, mask = -1;
    }
    {
	register struct in_ifaddr *ia;
	/*
	 * Check whether network is a subnet;
	 * if so, return subnet number.
	 */
	for (ia = in_ifaddr; ia; ia = ia->ia_next)
		if (net == ia->ia_net)
			mask =  ia->ia_subnetmask;
    }
    {
	register char *cpbase = (char *)&(sockmask->sin_addr);
	register char *cp = (char *)(1 + &(sockmask->sin_addr));

	sockmask->sin_addr.s_addr = htonl(mask);
	sockmask->sin_len = 0;
	while (--cp >= cpbase)
		if (*cp) {
			sockmask->sin_len = 1 + cp - (caddr_t)sockmask;
			break;
		}
    }
}

/*
 * Return the host portion of an internet address.
 */
u_long
in_lnaof(in)
	struct in_addr in;
{
	register u_long i = ntohl(in.s_addr);
	register u_long net, host;
	register struct in_ifaddr *ia;

	if (IN_CLASSA(i)) {
		net = i & IN_CLASSA_NET;
		host = i & IN_CLASSA_HOST;
	} else if (IN_CLASSB(i)) {
		net = i & IN_CLASSB_NET;
		host = i & IN_CLASSB_HOST;
	} else if (IN_CLASSC(i)) {
		net = i & IN_CLASSC_NET;
		host = i & IN_CLASSC_HOST;
	} else
		return (i);

	/*
	 * Check whether network is a subnet;
	 * if so, use the modified interpretation of `host'.
	 */
	for (ia = in_ifaddr; ia; ia = ia->ia_next)
		if (net == ia->ia_net)
			return (host &~ ia->ia_subnetmask);
	return (host);
}

#ifndef SUBNETSARELOCAL
#define	SUBNETSARELOCAL	1
#endif

#ifdef PROM
const int subnetsarelocal = SUBNETSARELOCAL;
#else
int subnetsarelocal = SUBNETSARELOCAL;
#endif

/*
 * Return 1 if an internet address is for a ``local'' host
 * (one to which we have a connection).  If subnetsarelocal
 * is true, this includes other subnets of the local net.
 * Otherwise, it includes only the directly-connected (sub)nets.
 */
in_localaddr(in)
	struct in_addr in;
{
	register u_long i = ntohl(in.s_addr);
	register struct in_ifaddr *ia;

	if (subnetsarelocal) {
		for (ia = in_ifaddr; ia; ia = ia->ia_next)
			if ((i & ia->ia_netmask) == ia->ia_net)
				return (1);
	} else {
		for (ia = in_ifaddr; ia; ia = ia->ia_next)
			if ((i & ia->ia_subnetmask) == ia->ia_subnet)
				return (1);
	}
	return (0);
}

/*
 * Determine whether an IP address is in a reserved set of addresses
 * that may not be forwarded, or whether datagrams to that destination
 * may be forwarded.
 */
in_canforward(in)
	struct in_addr in;
{
	register u_long i = ntohl(in.s_addr);
	register u_long net;

	if (IN_EXPERIMENTAL(i))
		return (0);
	if (IN_CLASSA(i)) {
		net = i & IN_CLASSA_NET;
		if (net == 0 || net == IN_LOOPBACKNET)
			return (0);
	}
	return (1);
}

int	in_interfaces;		/* number of external internet interfaces */
extern	struct ifnet loif;

/*
 * Generic internet control operations (ioctl's).
 * Ifp is 0 if not an interface-specific ioctl.
 */
/* ARGSUSED */
in_control(so, cmd, data, ifp)
	struct socket *so;
	int cmd;
	caddr_t data;
	register struct ifnet *ifp;
{
	register struct ifreq *ifr = (struct ifreq *)data;
	register struct in_ifaddr *ia = 0;
	register struct ifaddr *ifa;
	struct in_ifaddr *oia;
	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
	struct mbuf *m;
	struct sockaddr_in oldaddr;
	int error, hostIsNew, maskIsNew;
	u_long i;

	/*
	 * Find address for this interface, if it exists.
	 */
	if (ifp)
		for (ia = in_ifaddr; ia; ia = ia->ia_next)
			if (ia->ia_ifp == ifp)
				break;

	switch (cmd) {

	case SIOCAIFADDR:
	case SIOCDIFADDR:
		if (ifra->ifra_addr.sin_family == AF_INET)
		    for (oia = ia; ia; ia = ia->ia_next) {
			if (ia->ia_ifp == ifp  &&
			    ia->ia_addr.sin_addr.s_addr ==
				ifra->ifra_addr.sin_addr.s_addr)
			    break;
		}
		if (cmd == SIOCDIFADDR && ia == 0)
			return (EADDRNOTAVAIL);
		/* FALLTHROUGH */
	case SIOCSIFADDR:
	case SIOCSIFNETMASK:
	case SIOCSIFDSTADDR:
		if ((so->so_state & SS_PRIV) == 0)
			return (EPERM);

		if (ifp == 0)
			panic("in_control");
		if (ia == (struct in_ifaddr *)0) {
			m = m_getclr(M_WAIT, MT_IFADDR);
			if (m == (struct mbuf *)NULL)
				return (ENOBUFS);
			if (ia = in_ifaddr) {
				for ( ; ia->ia_next; ia = ia->ia_next)
					;
				ia->ia_next = mtod(m, struct in_ifaddr *);
			} else