in.c

基于组件方式开发操作系统的OSKIT源代码

/*
 * Copyright (c) 1982, 1986, 1991, 1993
 *	The 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	8.4 (Berkeley) 1/9/95
 *	$Id: in.c,v 1.39.2.1 1999/04/25 07:09:54 luigi Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sockio.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_var.h>

#include <netinet/igmp_var.h>

static MALLOC_DEFINE(M_IPMADDR, "in_multi", "internet multicast address");

static void	in_socktrim __P((struct sockaddr_in *));
static int	in_ifinit __P((struct ifnet *,
	    struct in_ifaddr *, struct sockaddr_in *, int));

static int subnetsarelocal = 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW, 
	&subnetsarelocal, 0, "");

struct in_multihead in_multihead; /* XXX BSS initialization */

/*
 * 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.
 */
int
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_ifaddrhead.tqh_first; ia; 
		     ia = ia->ia_link.tqe_next)
			if ((i & ia->ia_netmask) == ia->ia_net)
				return (1);
	} else {
		for (ia = in_ifaddrhead.tqh_first; ia;
		     ia = ia->ia_link.tqe_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.
 */
int
in_canforward(in)
	struct in_addr in;
{
	register u_long i = ntohl(in.s_addr);
	register u_long net;

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

/*
 * Trim a mask in a sockaddr
 */
static void
in_socktrim(ap)
struct sockaddr_in *ap;
{
    register char *cplim = (char *) &ap->sin_addr;
    register char *cp = (char *) (&ap->sin_addr + 1);

    ap->sin_len = 0;
    while (--cp >= cplim)
        if (*cp) {
	    (ap)->sin_len = cp - (char *) (ap) + 1;
	    break;
	}
}

static int in_interfaces;	/* number of external internet interfaces */

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

	/*
	 * Find address for this interface, if it exists.
	 *
	 * If an alias address was specified, find that one instead of
	 * the first one on the interface.
	 */
	if (ifp)
		for (iap = in_ifaddrhead.tqh_first; iap; 
		     iap = iap->ia_link.tqe_next)
			if (iap->ia_ifp == ifp) {
				if (((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr.s_addr ==
				    iap->ia_addr.sin_addr.s_addr) {
					ia = iap;
					break;
				} else if (ia == NULL) {
					ia = iap;
					if (ifr->ifr_addr.sa_family != AF_INET)
						break;
				}
			}

	switch (cmd) {

	case SIOCAIFADDR:
	case SIOCDIFADDR:
		if (ifp == 0)
			return (EADDRNOTAVAIL);
		if (ifra->ifra_addr.sin_family == AF_INET) {
			for (oia = ia; ia; ia = ia->ia_link.tqe_next) {
				if (ia->ia_ifp == ifp  &&
				    ia->ia_addr.sin_addr.s_addr ==
				    ifra->ifra_addr.sin_addr.s_addr)
					break;
			}
			if ((ifp->if_flags & IFF_POINTOPOINT)
			    && (cmd == SIOCAIFADDR)
			    && (ifra->ifra_dstaddr.sin_addr.s_addr
				== INADDR_ANY)) {
				return EDESTADDRREQ;
			}
		}
		if (cmd == SIOCDIFADDR && ia == 0)
			return (EADDRNOTAVAIL);
		/* FALLTHROUGH */
	case SIOCSIFADDR:
	case SIOCSIFNETMASK:
	case SIOCSIFDSTADDR:
		if (p && (error = suser(p->p_ucred, &p->p_acflag)) != 0)
			return error;

		if (ifp == 0)
			return (EADDRNOTAVAIL);
		if (ia == (struct in_ifaddr *)0) {
			ia = (struct in_ifaddr *)
				malloc(sizeof *ia, M_IFADDR, M_WAITOK);
			if (ia == (struct in_ifaddr *)NULL)
				return (ENOBUFS);
			bzero((caddr_t)ia, sizeof *ia);
			/*
			 * Protect from ipintr() traversing address list
			 * while we're modifying it.
			 */
			s = splnet();
			
			TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link);
			ifa = &ia->ia_ifa;
			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);

			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
			ia->ia_sockmask.sin_len = 8;
			if (ifp->if_flags & IFF_BROADCAST) {
				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
				ia->ia_broadaddr.sin_family = AF_INET;
			}
			ia->ia_ifp = ifp;
			if (!(ifp->if_flags & IFF_LOOPBACK))
				in_interfaces++;
			splx(s);
		}
		break;

	case SIOCSIFBRDADDR:
		if (p && (error = suser(p->p_ucred, &p->p_acflag)) != 0)
			return error;
		/* FALLTHROUGH */

	case SIOCGIFADDR:
	case SIOCGIFNETMASK:
	case SIOCGIFDSTADDR:
	case SIOCGIFBRDADDR:
		if (ia == (struct in_ifaddr *)0)
			return (EADDRNOTAVAIL);
		break;
	}
	switch (cmd) {

	case SIOCGIFADDR:
		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
		break;

	case SIOCGIFBRDADDR:
		if ((ifp->if_flags & IFF_BROADCAST) == 0)
			return (EINVAL);
		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
		break;

	case SIOCGIFDSTADDR:
		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
			return (EINVAL);
		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
		break;

	case SIOCGIFNETMASK:
		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
		break;

	case SIOCSIFDSTADDR:
		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
			return (EINVAL);
		oldaddr = ia->ia_dstaddr;
		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
		if (ifp->if_ioctl && (error = (*ifp->if_ioctl)
					(ifp, SIOCSIFDSTADDR, (caddr_t)ia))) {
			ia->ia_dstaddr = oldaddr;
			return (error);
		}
		if (ia->ia_flags & IFA_ROUTE) {
			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
			ia->ia_ifa.ifa_dstaddr =
					(struct sockaddr *)&ia->ia_dstaddr;
			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
		}
		break;

	case SIOCSIFBRDADDR:
		if ((ifp->if_flags & IFF_BROADCAST) == 0)
			return (EINVAL);
		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
		break;

	case SIOCSIFADDR:
		return (in_ifinit(ifp, ia,