BSD 4_4 release

[unix-history] / usr / src / sys / netinet / in.c

diff --git a/usr/src/sys/netinet/in.c b/usr/src/sys/netinet/in.c
index b5703fc..cee7e8a 100644 (file)
--- a/usr/src/sys/netinet/in.c
+++ b/usr/src/sys/netinet/in.c
@@ -1,114 +1,623 @@
-/*     in.c    4.9     82/10/21        */
-
-#include "../h/param.h"
-#include "../h/mbuf.h"
-#include "../h/protosw.h"
-#include "../h/socket.h"
-#include "../h/socketvar.h"
-#include "../netinet/in.h"
-#include "../netinet/in_systm.h"
-#include "../net/if.h"
-#include "../net/route.h"
-#include "../net/af.h"
+/*
+ * 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        8.1 (Berkeley) 6/10/93
+ */
+
+#include <sys/param.h>
+#include <sys/ioctl.h>
+#include <sys/errno.h>
+#include <sys/malloc.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+
+#include <net/if.h>
+#include <net/route.h>
+#include <net/af.h>
+
+#include <netinet/in_systm.h>
+#include <netinet/in.h>
+#include <netinet/in_var.h>
+#include <netinet/if_ether.h>

 
 #ifdef INET
 
 #ifdef INET

-inet_hash(sin, hp)
-       register struct sockaddr_in *sin;
-       struct afhash *hp;
+/*
+ * 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;

 
 

-       hp->afh_nethash = in_netof(sin->sin_addr);
-       hp->afh_hosthash = sin->sin_addr.s_addr;
-#if vax || pdp11 || ns16032
-       hp->afh_hosthash = ntohl((u_long)hp->afh_hosthash);
+       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 if (IN_CLASSD(i))
+               net = i & IN_CLASSD_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);
+}
+
+#ifndef SUBNETSARELOCAL
+#define        SUBNETSARELOCAL 1

 #endif
 #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);

 }
 
 }
 

-inet_netmatch(sin1, sin2)
-       struct sockaddr_in *sin1, *sin2;
+/*
+ * 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;

 
 

-       return (sin1->sin_addr.s_net == sin2->sin_addr.s_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);

 }
 
 /*
 }
 
 /*

- * Formulate an Internet address from network + host.  Used in
- * building addresses stored in the ifnet structure.
+ * Trim a mask in a sockaddr

  */
  */

-struct in_addr
-if_makeaddr(net, host)
-       int net, host;
+void
+in_socktrim(ap)
+struct sockaddr_in *ap;

 {
 {

-       u_long addr;
+    register char *cplim = (char *) &ap->sin_addr;
+    register char *cp = (char *) (&ap->sin_addr + 1);

 
 

-       if (net < 128)
-               addr = (net << IN_CLASSA_NSHIFT) | host;
-       else if (net < 65536)
-               addr = (net << IN_CLASSB_NSHIFT) | host;
-       else
-               addr = (net << IN_CLASSC_NSHIFT) | host;
-#ifdef vax || pdp11 || ns16032
-       addr = htonl(addr);
-#endif
-       return (*(struct in_addr *)&addr);
+    ap->sin_len = 0;
+    while (--cp > cplim)
+        if (*cp) {
+           (ap)->sin_len = cp - (char *) (ap) + 1;
+           break;
+       }

 }
 
 }
 

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

 /*
 /*

- * Return the network number from an internet address.
+ * Generic internet control operations (ioctl's).
+ * Ifp is 0 if not an interface-specific ioctl.

  */
  */

-in_netof(in)
-       struct in_addr in;
+/* ARGSUSED */
+in_control(so, cmd, data, ifp)
+       struct socket *so;
+       int cmd;
+       caddr_t data;
+       register struct ifnet *ifp;

 {
 {

-       register u_long i = in.s_addr;
+       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 sockaddr_in oldaddr;
+       int error, hostIsNew, maskIsNew;
+       u_long i;

 
 

-#ifdef vax || pdp11 || ns16032
-       i = ntohl(i);
-#endif
-       if (IN_CLASSA(i))
-               return (((i)&IN_CLASSA_NET) >> IN_CLASSA_NSHIFT);
-       else if (IN_CLASSB(i))
-               return (((i)&IN_CLASSB_NET) >> IN_CLASSB_NSHIFT);
+       /*
+        * 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) {
+                       oia = (struct in_ifaddr *)
+                               malloc(sizeof *oia, M_IFADDR, M_WAITOK);
+                       if (oia == (struct in_ifaddr *)NULL)
+                               return (ENOBUFS);
+                       bzero((caddr_t)oia, sizeof *oia);
+                       if (ia = in_ifaddr) {
+                               for ( ; ia->ia_next; ia = ia->ia_next)
+                                       continue;
+                               ia->ia_next = oia;
+                       } else
+                               in_ifaddr = oia;
+                       ia = oia;
+                       if (ifa = ifp->if_addrlist) {
+                               for ( ; ifa->ifa_next; ifa = ifa->ifa_next)
+                                       continue;
+                               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 ((so->so_state & SS_PRIV) == 0)
+                       return (EPERM);
+               /* 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,
+                   (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 = 0;
+               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");
+               }
+               IFAFREE((&oia->ia_ifa));
+               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.
+ */
+void
+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
        else

-               return (((i)&IN_CLASSC_NET) >> IN_CLASSC_NSHIFT);
+               rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0);
+       ia->ia_flags &= ~IFA_ROUTE;

 }
 
 }
 

-#ifdef notdef

 /*
 /*

- * Return the host portion of an internet address.
+ * Initialize an interface's internet address
+ * and routing table entry.

  */
  */

-in_lnaof(in)
-       struct in_addr in;
+in_ifinit(ifp, ia, sin, scrub)
+       register struct ifnet *ifp;
+       register struct in_ifaddr *ia;
+       struct sockaddr_in *sin;
+       int scrub;

 {
 {

-       register u_long i = in.s_addr;
+       register u_long i = ntohl(sin->sin_addr.s_addr);
+       struct sockaddr_in oldaddr;
+       int s = splimp(), flags = RTF_UP, error, ether_output();

 
 

-#ifdef vax || pdp11 || ns16032
-       i = ntohl(i);
-#endif
+       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, (caddr_t)ia))) {
+               splx(s);
+               ia->ia_addr = oldaddr;
+               return (error);
+       }
+       if (ifp->if_output == ether_output) { /* XXX: Another Kludge */
+               ia->ia_ifa.ifa_rtrequest = arp_rtrequest;
+               ia->ia_ifa.ifa_flags |= RTF_CLONING;
+       }
+       splx(s);
+       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))
        if (IN_CLASSA(i))

-               return ((i)&IN_CLASSA_HOST);
+               ia->ia_netmask = IN_CLASSA_NET;

        else if (IN_CLASSB(i))
        else if (IN_CLASSB(i))

-               return ((i)&IN_CLASSB_HOST);
+               ia->ia_netmask = IN_CLASSB_NET;

        else
        else

-               return ((i)&IN_CLASSC_HOST);
+               ia->ia_netmask = IN_CLASSC_NET;
+       /*
+        * The subnet mask usually includes at least the standard network part,
+        * but may may be smaller in the case of supernetting.
+        * If it is set, we believe it.
+        */
+       if (ia->ia_subnetmask == 0) {
+               ia->ia_subnetmask = ia->ia_netmask;
+               ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
+       } else
+               ia->ia_netmask &= ia->ia_subnetmask;
+       ia->ia_net = i & ia->ia_netmask;
+       ia->ia_subnet = i & ia->ia_subnetmask;
+       in_socktrim(&ia->ia_sockmask);
+       /*
+        * Add route for the network.
+        */
+       ia->ia_ifa.ifa_metric = ifp->if_metric;
+       if (ifp->if_flags & IFF_BROADCAST) {
+               ia->ia_broadaddr.sin_addr.s_addr =
+                       htonl(ia->ia_subnet | ~ia->ia_subnetmask);
+               ia->ia_netbroadcast.s_addr =
+                       htonl(ia->ia_net | ~ ia->ia_netmask);
+       } else if (ifp->if_flags & IFF_LOOPBACK) {
+               ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr;
+               flags |= RTF_HOST;
+       } else if (ifp->if_flags & IFF_POINTOPOINT) {
+               if (ia->ia_dstaddr.sin_family != AF_INET)
+                       return (0);
+               flags |= RTF_HOST;
+       }
+       if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD, flags)) == 0)
+               ia->ia_flags |= IFA_ROUTE;
+       /*
+        * If the interface supports multicast, join the "all hosts"
+        * multicast group on that interface.
+        */
+       if (ifp->if_flags & IFF_MULTICAST) {
+               struct in_addr addr;
+
+               addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
+               in_addmulti(&addr, ifp);
+       }
+       return (error);

 }
 }

-#endif
+

 
 /*
 
 /*

- * Initialize an interface's routing
- * table entry according to the network.
- * INTERNET SPECIFIC.
+ * Return 1 if the address might be a local broadcast address.

  */
  */

-if_rtinit(ifp, flags)
+in_broadcast(in, ifp)
+       struct in_addr in;
+        struct ifnet *ifp;
+{
+       register struct ifaddr *ifa;
+       u_long t;
+
+       if (in.s_addr == INADDR_BROADCAST ||
+           in.s_addr == INADDR_ANY)
+               return 1;
+       if ((ifp->if_flags & IFF_BROADCAST) == 0)
+               return 0;
+       t = ntohl(in.s_addr);
+       /*
+        * Look through the list of addresses for a match
+        * with a broadcast address.
+        */
+#define ia ((struct in_ifaddr *)ifa)
+       for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
+               if (ifa->ifa_addr->sa_family == AF_INET &&
+                   (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
+                    in.s_addr == ia->ia_netbroadcast.s_addr ||
+                    /*
+                     * Check for old-style (host 0) broadcast.
+                     */
+                    t == ia->ia_subnet || t == ia->ia_net))
+                           return 1;
+       return (0);
+#undef ia
+}
+/*
+ * Add an address to the list of IP multicast addresses for a given interface.
+ */
+struct in_multi *
+in_addmulti(ap, ifp)
+       register struct in_addr *ap;

        register struct ifnet *ifp;
        register struct ifnet *ifp;

-       int flags;

 {
 {

-       struct sockaddr_in sin;
+       register struct in_multi *inm;
+       struct ifreq ifr;
+       struct in_ifaddr *ia;
+       int s = splnet();

 
 

-       if (ifp->if_flags & IFF_ROUTE)
-               return;
-       bzero((caddr_t)&sin, sizeof (sin));
-       sin.sin_family = AF_INET;
-       sin.sin_addr = if_makeaddr(ifp->if_net, 0);
-       rtinit((struct sockaddr *)&sin, &ifp->if_addr, flags);
+       /*
+        * See if address already in list.
+        */
+       IN_LOOKUP_MULTI(*ap, ifp, inm);
+       if (inm != NULL) {
+               /*
+                * Found it; just increment the reference count.
+                */
+               ++inm->inm_refcount;
+       }
+       else {
+               /*
+                * New address; allocate a new multicast record
+                * and link it into the interface's multicast list.
+                */
+               inm = (struct in_multi *)malloc(sizeof(*inm),
+                   M_IPMADDR, M_NOWAIT);
+               if (inm == NULL) {
+                       splx(s);
+                       return (NULL);
+               }
+               inm->inm_addr = *ap;
+               inm->inm_ifp = ifp;
+               inm->inm_refcount = 1;
+               IFP_TO_IA(ifp, ia);
+               if (ia == NULL) {
+                       free(inm, M_IPMADDR);
+                       splx(s);
+                       return (NULL);
+               }
+               inm->inm_ia = ia;
+               inm->inm_next = ia->ia_multiaddrs;
+               ia->ia_multiaddrs = inm;
+               /*
+                * Ask the network driver to update its multicast reception
+                * filter appropriately for the new address.
+                */
+               ((struct sockaddr_in *)&ifr.ifr_addr)->sin_family = AF_INET;
+               ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr = *ap;
+               if ((ifp->if_ioctl == NULL) ||
+                   (*ifp->if_ioctl)(ifp, SIOCADDMULTI,(caddr_t)&ifr) != 0) {
+                       ia->ia_multiaddrs = inm->inm_next;
+                       free(inm, M_IPMADDR);
+                       splx(s);
+                       return (NULL);
+               }
+               /*
+                * Let IGMP know that we have joined a new IP multicast group.
+                */
+               igmp_joingroup(inm);
+       }
+       splx(s);
+       return (inm);
+}
+
+/*
+ * Delete a multicast address record.
+ */
+int
+in_delmulti(inm)
+       register struct in_multi *inm;
+{
+       register struct in_multi **p;
+       struct ifreq ifr;
+       int s = splnet();
+
+       if (--inm->inm_refcount == 0) {
+               /*
+                * No remaining claims to this record; let IGMP know that
+                * we are leaving the multicast group.
+                */
+               igmp_leavegroup(inm);
+               /*
+                * Unlink from list.
+                */
+               for (p = &inm->inm_ia->ia_multiaddrs;
+                    *p != inm;
+                    p = &(*p)->inm_next)
+                        continue;
+               *p = (*p)->inm_next;
+               /*
+                * Notify the network driver to update its multicast reception
+                * filter.
+                */
+               ((struct sockaddr_in *)&(ifr.ifr_addr))->sin_family = AF_INET;
+               ((struct sockaddr_in *)&(ifr.ifr_addr))->sin_addr =
+                                                               inm->inm_addr;
+               (*inm->inm_ifp->if_ioctl)(inm->inm_ifp, SIOCDELMULTI,
+                                                            (caddr_t)&ifr);
+               free(inm, M_IPMADDR);
+       }
+       splx(s);

 }
 #endif
 }
 #endif