in.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char *sccsid = "@(#)in.c	4.1		(ULTRIX)	7/2/90";
#endif lint

/************************************************************************
 *									*
 *			Copyright (c) 1985 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *			Modification History				*
 *	8-Nov-89	Ursula Sinkewicz
 *		Remove lk_ifnet and lk_in_ifaddr to coincides with 
 *		changes to slip.
 *
 *	9-June-89	Ursula Sinkewicz
 *		Added changes for asymmetric network drivers.
 *
 *	27-Mar-89	Ursula Sinkewicz
 *		Lower ipl of lk_ifnet, lk_in_ifaddr, lk_retentry as
 *		per lp changes 3//16/89.
 *
 *	3-Mar-89	Ursula Sinkewicz
 *		Pmax/smp merge.  Added CLASSA/B checks in in_localaddr.
 *
 *	13-Feb-89	Ursula Sinkewicz
 *		Changed kmalloc flag to nowait.  Added assertions of 
 *		lk_in_ifaddr and lk_ifnet.
 *	
 *	15-Jan-88	lp
 *		Merge of final 43BSD changes.
 *
 *	Larry Cohen  -	09/16/85					*
 * 		Add 43bsd alpha tape changes for subnet routing		*
 *									*
 *	Larry Cohen  -  01/17/86					*
 *		Add boolean: net_conservative.  If set then a different *
 *		subnet will be viewed as non-local in in_localaddr().   *
 *		This will result in tcp using the default maxseg size   *
 *		instead of the mtu of the local interface.		*
 *									*
 *	Marc Teitelbaum and Fred Templin - 08/21/86			*
 *		Added 4.3BSD beta tape enhancements. "in_interfaces"	*
 *		to count number of physical interfaces attached. Also,	*
 *		new code for SICSIFBRDADDR ioctl to init		*
 *		"ia_netbroadcast"					*
 *									*
 *	12/16/86 - lp							*
 *		Bugfix for changing addr.				*
 *									*
 *									*
 ************************************************************************/

/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *	in.c	7.5 (Berkeley) 6/4/87
 */

#include "../h/param.h"
#include "../h/ioctl.h"
#include "../h/mbuf.h"
#include "../h/protosw.h"
#include "../h/socket.h"
#include "../h/socketvar.h"
#include "../h/uio.h"
#include "../h/dir.h"

#include "../h/cpudata.h"
#include "../h/user.h"
#include "../h/buf.h"
#include "../h/conf.h"
#include "../h/proc.h"
#include "../h/smp_lock.h"
#include "../net/netinet/in_systm.h"
#include "../net/net/if.h"
#include "../net/net/route.h"
#include "../net/net/af.h"
#include "../net/netinet/in.h"
#include "../net/netinet/in_var.h"

struct lock_t lk_in_ifaddr;	/* smp */
#ifdef INET
inet_hash(sin, hp)
	register struct sockaddr_in *sin;
	struct afhash *hp;
{
	register u_long n;

	n = in_netof(sin->sin_addr);
	if (n)
	    while ((n & 0xff) == 0)
		n >>= 8;
	hp->afh_nethash = n;
	hp->afh_hosthash = ntohl(sin->sin_addr.s_addr);
}

inet_netmatch(sin1, sin2)
	struct sockaddr_in *sin1, *sin2;
{

	return (in_netof(sin1->sin_addr) == in_netof(sin2->sin_addr));
}

/*
 * 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 ((ia->ia_netmask & net) == ia->ia_net){
			return (i & ia->ia_subnetmask);
		}
	return (net);
}

/*
 * 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;
	u_long host_return;

	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'.
	 */
/* NO LOCK */
	for (ia = in_ifaddr; ia; ia = ia->ia_next)
		if ((ia->ia_netmask & net) == ia->ia_net){
			host_return = host &~ ia->ia_subnetmask;
			return (host_return);
		}
	return (host);
}

#ifndef SUBNETSARELOCAL
#define SUBNETSARELOCAL 1
#endif
int subnetsarelocal = SUBNETSARELOCAL;
/*
 * 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;
	u_long net;

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

        for (ia = in_ifaddr; ia; ia = ia->ia_next)
                if (net == (subnetsarelocal ? ia->ia_net : 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;
	u_long tmp;
	struct ifaddr *ifa;
	struct mbuf *m;
	int error;
	int saveaffinity;  /* support for nonsmp dvrs.  8.9.88.us */

	/*
	 * 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 SIOCSIFADDR:
	case SIOCSIFNETMASK:
	case SIOCSIFDSTADDR: