usr/src/sys/netinet/in.c

/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *      @(#)in.c        7.10 (Berkeley) %G%
 */

#include "param.h"
#include "ioctl.h"
#include "mbuf.h"
#include "protosw.h"
#include "socket.h"
#include "socketvar.h"
#include "uio.h"
#include "dir.h"
#include "user.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 *cp = (char *)&(sockmask->sin_port);
        register char *cpbase = (char *)&(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
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;

        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 (!suser())
                        return (u.u_error);

                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
                                in_ifaddr = mtod(m, struct in_ifaddr *);
                        ia = mtod(m, struct in_ifaddr *);
                        if (ifa = ifp->if_addrlist) {
                                for ( ; ifa->ifa_next; ifa = ifa->ifa_next)
                                        ;
                                ifa->ifa_next = (struct ifaddr *) ia;
                        } else
                                ifp->if_addrlist = (struct ifaddr *) ia;
                        ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
                        ia->ia_ifa.ifa_dstaddr
                                        = (struct sockaddr *)&ia->ia_dstaddr;
                        ia->ia_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 != &loif)
                                in_interfaces++;
                }
                break;

        case SIOCSIFBRDADDR:
                if (!suser())
                        return (u.u_error);
                /* FALLTHROUGH */

        default:
                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, 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_addr;
                        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,
                    (struct sockaddr_in *) &ifr->ifr_addr, 1));

        case SIOCSIFNETMASK:
                i = ifra->ifra_addr.sin_addr.s_addr;
                ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr = i);
                break;

        case SIOCAIFADDR:
                maskIsNew = 0; hostIsNew = 1; error = u.u_error;
                if (ia->ia_addr.sin_family == AF_INET) {
                        if (ifra->ifra_addr.sin_len == 0) {
                                ifra->ifra_addr = ia->ia_addr;
                                hostIsNew = 0;
                        } else if (ifra->ifra_addr.sin_addr.s_addr ==
                                               ia->ia_addr.sin_addr.s_addr)
                                hostIsNew = 0;
                }
                if (ifra->ifra_mask.sin_len) {
                        in_ifscrub(ifp, ia);
                        ia->ia_sockmask = ifra->ifra_mask;
                        ia->ia_subnetmask =
                                        ntohl(ia->ia_sockmask.sin_addr.s_addr);
                        maskIsNew = 1;
                }
                if ((ifp->if_flags & IFF_POINTOPOINT) &&
                    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
                        in_ifscrub(ifp, ia);
                        ia->ia_dstaddr = ifra->ifra_dstaddr;
                        maskIsNew  = 1; /* We lie; but the effect's the same */
                }
                if (ifra->ifra_addr.sin_family == AF_INET &&
                                            (hostIsNew || maskIsNew))
                        error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
                if ((ifp->if_flags & IFF_BROADCAST) &&
                    (ifra->ifra_broadaddr.sin_family == AF_INET))
                        ia->ia_broadaddr = ifra->ifra_broadaddr;
                return (error);

        case SIOCDIFADDR:
                in_ifscrub(ifp, ia);
                if ((ifa = ifp->if_addrlist) == (struct ifaddr *)ia)
                        ifp->if_addrlist = ifa->ifa_next;
                else {
                        while (ifa->ifa_next &&
                               (ifa->ifa_next != (struct ifaddr *)ia))
                                    ifa = ifa->ifa_next;
                        if (ifa->ifa_next)
                            ifa->ifa_next = ((struct ifaddr *)ia)->ifa_next;
                        else
                                printf("Couldn't unlink inifaddr from ifp\n");
                }
                oia = ia;
                if (oia == (ia = in_ifaddr)) {
                        in_ifaddr = ia->ia_next;
                } else {
                        while (ia->ia_next && (ia->ia_next != oia)) {
                                ia = ia->ia_next;
                        }
                        if (ia->ia_next)
                            ia->ia_next = oia->ia_next;
                        else
                                printf("Didn't unlink inifadr from list\n");
                }
                (void) m_free(dtom(oia));
                break;

        default:
                if (ifp == 0 || ifp->if_ioctl == 0)
                        return (EOPNOTSUPP);
                return ((*ifp->if_ioctl)(ifp, cmd, data));
        }
        return (0);
}

/*
 * Delete any existing route for an interface.
 */
in_ifscrub(ifp, ia)
        register struct ifnet *ifp;
        register struct in_ifaddr *ia;
{

        if ((ia->ia_flags & IFA_ROUTE) == 0)
                return;
        if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT))
                rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
        else
                rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
        ia->ia_flags &= ~IFA_ROUTE;
}

/*
 * Initialize an interface's internet address
 * and routing table entry.
 */
in_ifinit(ifp, ia, sin, scrub)
        register struct ifnet *ifp;
        register struct in_ifaddr *ia;
        struct sockaddr_in *sin;
{
        register u_long i = ntohl(sin->sin_addr.s_addr);
        struct sockaddr_in oldaddr;
        int s = splimp(), error;

        oldaddr = ia->ia_addr;
        ia->ia_addr = *sin;
        /*
         * Give the interface a chance to initialize
         * if this is its first address,
         * and to validate the address if necessary.
         */
        if (ifp->if_ioctl && (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, ia))) {
                splx(s);
                ia->ia_addr = oldaddr;
                return (error);
        }
        if (scrub) {
                ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
                in_ifscrub(ifp, ia);
                ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
        }
        if (IN_CLASSA(i))
                ia->ia_netmask = IN_CLASSA_NET;
        else if (IN_CLASSB(i))
                ia->ia_netmask = IN_CLASSB_NET;
        else
                ia->ia_netmask = IN_CLASSC_NET;
        ia->ia_net = i & ia->ia_netmask;
        /*
         * The subnet mask includes at least the standard network part,
         * but may already have been set to a larger value.
         */
        ia->ia_subnetmask |= ia->ia_netmask;
        ia->ia_subnet = i & ia->ia_subnetmask;
        ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
        if (ifp->if_flags & IFF_BROADCAST) {
                ia->ia_broadaddr.sin_addr =
                        in_makeaddr(ia->ia_subnet, INADDR_BROADCAST);
                ia->ia_netbroadcast.s_addr =
                    htonl(ia->ia_net | (INADDR_BROADCAST &~ ia->ia_netmask));
        }
        /*
         * Add route for the network.
         */
        if (ifp->if_flags & IFF_LOOPBACK) {
                ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
                rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
        } else if (ifp->if_flags & IFF_POINTOPOINT &&
                 ia->ia_dstaddr.sin_family == AF_INET)
                rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
        else {
                rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_UP);
        }
        ia->ia_flags |= IFA_ROUTE;
        splx(s);
        return (0);
}

/*
 * Return address info for specified internet network.
 */
struct in_ifaddr *
in_iaonnetof(net)
        u_long net;
{
        register struct in_ifaddr *ia;

        for (ia = in_ifaddr; ia; ia = ia->ia_next)
                if (ia->ia_subnet == net)
                        return (ia);
        return ((struct in_ifaddr *)0);
}

/*
 * Return 1 if the address might be a local broadcast address.
 */
in_broadcast(in)
        struct in_addr in;
{
        register struct in_ifaddr *ia;
        u_long t;

        /*
         * Look through the list of addresses for a match
         * with a broadcast address.
         */
        for (ia = in_ifaddr; ia; ia = ia->ia_next)
            if (ia->ia_ifp->if_flags & IFF_BROADCAST) {
                if (ia->ia_broadaddr.sin_addr.s_addr == in.s_addr)
                     return (1);
                /*
                 * Check for old-style (host 0) broadcast.
                 */
                if ((t = ntohl(in.s_addr)) == ia->ia_subnet || t == ia->ia_net)
                    return (1);
        }
        if (in.s_addr == INADDR_BROADCAST || in.s_addr == INADDR_ANY)
                return (1);
        return (0);
}
#endif