NetBSD/sys/net/if_ethersubr.c

/*	$NetBSD: if_ethersubr.c,v 1.38 1998/10/13 02:34:32 kim Exp $	*/

/*
 * Copyright (c) 1982, 1989, 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.
 *
 *	@(#)if_ethersubr.c	8.2 (Berkeley) 4/4/96
 */

#include "opt_inet.h"
#include "opt_atalk.h"
#include "opt_ccitt.h"
#include "opt_llc.h"
#include "opt_iso.h"
#include "opt_ns.h"
#include "opt_gateway.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/syslog.h>

#include <machine/cpu.h>

#include <net/if.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/if_llc.h>
#include <net/if_dl.h>
#include <net/if_types.h>

#include <net/if_ether.h>

#include <netinet/in.h>
#ifdef INET
#include <netinet/in_var.h>
#endif
#include <netinet/if_inarp.h>

#ifdef NS
#include <netns/ns.h>
#include <netns/ns_if.h>
#endif

#ifdef IPX
#include <netipx/ipx.h>
#include <netipx/ipx_if.h>
#endif

#ifdef ISO
#include <netiso/argo_debug.h>
#include <netiso/iso.h>
#include <netiso/iso_var.h>
#include <netiso/iso_snpac.h>
#endif

#ifdef LLC
#include <netccitt/dll.h>
#include <netccitt/llc_var.h>
#endif

#if defined(LLC) && defined(CCITT)
extern struct ifqueue pkintrq;
#endif

#ifdef NETATALK
#include <netatalk/at.h>
#include <netatalk/at_var.h>
#include <netatalk/at_extern.h>

#define llc_snap_org_code llc_un.type_snap.org_code
#define llc_snap_ether_type llc_un.type_snap.ether_type

extern u_char	at_org_code[3];
extern u_char	aarp_org_code[3];
#endif /* NETATALK */

u_char	etherbroadcastaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
#define senderr(e) { error = (e); goto bad;}

#define SIN(x) ((struct sockaddr_in *)x)

/*
 * Ethernet output routine.
 * Encapsulate a packet of type family for the local net.
 * Assumes that ifp is actually pointer to ethercom structure.
 */
int
ether_output(ifp, m0, dst, rt0)
	struct ifnet *ifp;
	struct mbuf *m0;
	struct sockaddr *dst;
	struct rtentry *rt0;
{
	u_int16_t etype;
	int s, error = 0, hdrcmplt = 0;
 	u_char esrc[6], edst[6];
	struct mbuf *m = m0;
	struct rtentry *rt;
	struct mbuf *mcopy = (struct mbuf *)0;
	struct ether_header *eh;
#ifdef INET
	struct arphdr *ah;
#endif /* INET */
#ifdef NETATALK
	struct at_ifaddr *aa;
#endif /* NETATALK */

	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
		senderr(ENETDOWN);
	ifp->if_lastchange = time;
	if ((rt = rt0) != NULL) {
		if ((rt->rt_flags & RTF_UP) == 0) {
			if ((rt0 = rt = rtalloc1(dst, 1)) != NULL) {
				rt->rt_refcnt--;
				if (rt->rt_ifp != ifp)
					return (*rt->rt_ifp->if_output)
							(ifp, m0, dst, rt);
			} else 
				senderr(EHOSTUNREACH);
		}
		if ((rt->rt_flags & RTF_GATEWAY) && dst->sa_family != AF_NS) {
			if (rt->rt_gwroute == 0)
				goto lookup;
			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
				rtfree(rt); rt = rt0;
			lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
				if ((rt = rt->rt_gwroute) == 0)
					senderr(EHOSTUNREACH);
				/* the "G" test below also prevents rt == rt0 */
				if ((rt->rt_flags & RTF_GATEWAY) ||
				    (rt->rt_ifp != ifp)) {
					rt->rt_refcnt--;
					rt0->rt_gwroute = 0;
					senderr(EHOSTUNREACH);
				}
			}
		}
		if (rt->rt_flags & RTF_REJECT)
			if (rt->rt_rmx.rmx_expire == 0 ||
			    time.tv_sec < rt->rt_rmx.rmx_expire)
				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
	}
	switch (dst->sa_family) {

#ifdef INET
	case AF_INET:
		if (m->m_flags & M_BCAST)
                	bcopy((caddr_t)etherbroadcastaddr, (caddr_t)edst,
				sizeof(edst));

		else if (m->m_flags & M_MCAST) {
			ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr,
			    (caddr_t)edst)

		} else if (!arpresolve(ifp, rt, m, dst, edst))
			return (0);	/* if not yet resolved */
		/* If broadcasting on a simplex interface, loopback a copy */
		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
			mcopy = m_copy(m, 0, (int)M_COPYALL);
		etype = htons(ETHERTYPE_IP);
		break;

	case AF_ARP:
		ah = mtod(m, struct arphdr *);
		if (m->m_flags & M_BCAST)
                	bcopy((caddr_t)etherbroadcastaddr, (caddr_t)edst,
				sizeof(edst));
		else
			bcopy((caddr_t)ar_tha(ah),
				(caddr_t)edst, sizeof(edst));
		
		ah->ar_hrd = htons(ARPHRD_ETHER);

		switch(ntohs(ah->ar_op)) {
		case ARPOP_REVREQUEST:
		case ARPOP_REVREPLY:
			etype = htons(ETHERTYPE_REVARP);
			break;

		case ARPOP_REQUEST:
		case ARPOP_REPLY:
		default:
			etype = htons(ETHERTYPE_ARP);
		}

		break;
#endif
#ifdef NETATALK
    case AF_APPLETALK:
		if (!aarpresolve(ifp, m, (struct sockaddr_at *)dst, edst)) {
#ifdef NETATALKDEBUG
			printf("aarpresolv failed\n");
#endif /* NETATALKDEBUG */
			return (0);
		}
		/*
		 * ifaddr is the first thing in at_ifaddr
		 */
		aa = (struct at_ifaddr *) at_ifawithnet(
		    (struct sockaddr_at *)dst, ifp);
		if (aa == NULL)
		    goto bad;
		
		/*
		 * In the phase 2 case, we need to prepend an mbuf for the
		 * llc header.  Since we must preserve the value of m,
		 * which is passed to us by value, we m_copy() the first
		 * mbuf, and use it for our llc header.
		 */
		if (aa->aa_flags & AFA_PHASE2) {
			struct llc llc;

			M_PREPEND(m, sizeof(struct llc), M_WAIT);
			llc.llc_dsap = llc.llc_ssap = LLC_SNAP_LSAP;
			llc.llc_control = LLC_UI;
			bcopy(at_org_code, llc.llc_snap_org_code,
			    sizeof(llc.llc_snap_org_code));
			llc.llc_snap_ether_type = htons(ETHERTYPE_ATALK);
			bcopy(&llc, mtod(m, caddr_t), sizeof(struct llc));
			etype = htons(m->m_pkthdr.len);
		} else {
			etype = htons(ETHERTYPE_ATALK);
		}
		break;
#endif /* NETATALK */
#ifdef NS
	case AF_NS:
		etype = htons(ETHERTYPE_NS);
 		bcopy((caddr_t)&(((struct sockaddr_ns *)dst)->sns_addr.x_host),
		    (caddr_t)edst, sizeof (edst));
		if (!bcmp((caddr_t)edst, (caddr_t)&ns_thishost, sizeof(edst)))
			return (looutput(ifp, m, dst, rt));
		/* If broadcasting on a simplex interface, loopback a copy */
		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
			mcopy = m_copy(m, 0, (int)M_COPYALL);
		break;
#endif
#ifdef IPX
	case AF_IPX:
		etype = ETHERTYPE_IPX;
 		bcopy((caddr_t)&satosipx(dst)->sipx_addr.ipx_host,
		    (caddr_t)edst, sizeof (edst));
		if (!bcmp((caddr_t)edst, (caddr_t)&ipx_thishost, sizeof(edst)))
			return (looutput(ifp, m, dst, rt));
		/* If broadcasting on a simplex interface, loopback a copy */
		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
			mcopy = m_copy(m, 0, (int)M_COPYALL);
		break;
#endif
#ifdef	ISO
	case AF_ISO: {
		int	snpalen;
		struct	llc *l;
		struct sockaddr_dl *sdl;

		if (rt && (sdl = (struct sockaddr_dl *)rt->rt_gateway) &&
		    sdl->sdl_family == AF_LINK && sdl->sdl_alen > 0) {
			bcopy(LLADDR(sdl), (caddr_t)edst, sizeof(edst));
		} else {
			error = iso_snparesolve(ifp, (struct sockaddr_iso *)dst,
						(char *)edst, &snpalen);
			if (error)
				goto bad; /* Not Resolved */
		}
		/* If broadcasting on a simplex interface, loopback a copy */
		if (*edst & 1)
			m->m_flags |= (M_BCAST|M_MCAST);
		if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX) &&
		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
			if (mcopy) {
				eh = mtod(mcopy, struct ether_header *);
				bcopy((caddr_t)edst,
				      (caddr_t)eh->ether_dhost, sizeof (edst));
				bcopy(LLADDR(ifp->if_sadl),
				      (caddr_t)eh->ether_shost, sizeof (edst));
			}
		}
		M_PREPEND(m, 3, M_DONTWAIT);
		if (m == NULL)
			return (0);
		etype = htons(m->m_pkthdr.len);
		l = mtod(m, struct llc *);
		l->llc_dsap = l->llc_ssap = LLC_ISO_LSAP;
		l->llc_control = LLC_UI;
#ifdef ARGO_DEBUG
		if (argo_debug[D_ETHER]) {
			int i;
			printf("unoutput: sending pkt to: ");
			for (i=0; i<6; i++)
				printf("%x ", edst[i] & 0xff);
			printf("\n");
		}
#endif
		} break;
#endif /* ISO */
#ifdef	LLC
/*	case AF_NSAP: */
	case AF_CCITT: {
		struct sockaddr_dl *sdl = 
			(struct sockaddr_dl *) rt -> rt_gateway;

		if (sdl && sdl->sdl_family == AF_LINK
		    && sdl->sdl_alen > 0) {
			bcopy(LLADDR(sdl), (char *)edst,
				sizeof(edst));
		} else goto bad; /* Not a link interface ? Funny ... */
		if ((ifp->if_flags & IFF_SIMPLEX) && (*edst & 1) &&
		    (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
			M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
			if (mcopy) {
				eh = mtod(mcopy, struct ether_header *);
				bcopy((caddr_t)edst,
				      (caddr_t)eh->ether_dhost, sizeof (edst));
				bcopy(LLADDR(ifp->if_sadl),
				      (caddr_t)eh->ether_shost, sizeof (edst));
			}
		}
		etype = htons(m->m_pkthdr.len);
#ifdef LLC_DEBUG
		{
			int i;
			struct llc *l = mtod(m, struct llc *);

			printf("ether_output: sending LLC2 pkt to: ");
			for (i=0; i<6; i++)
				printf("%x ", edst[i] & 0xff);
			printf(" len 0x%x dsap 0x%x ssap 0x%x control 0x%x\n", 
			    m->m_pkthdr.len, l->llc_dsap & 0xff, l->llc_ssap &0xff,
			    l->llc_control & 0xff);

		}
#endif /* LLC_DEBUG */
		} break;
#endif /* LLC */	

	case pseudo_AF_HDRCMPLT:
		hdrcmplt = 1;
		eh = (struct ether_header *)dst->sa_data;
		bcopy((caddr_t)eh->ether_shost, (caddr_t)esrc, sizeof (esrc));
		/* FALLTHROUGH */

	case AF_UNSPEC:
		eh = (struct ether_header *)dst->sa_data;
 		bcopy((caddr_t)eh->ether_dhost, (caddr_t)edst, sizeof (edst));
		/* AF_UNSPEC doesn't swap the byte order of the ether_type. */
		etype = eh->ether_type;
		break;

	default:
		printf("%s: can't handle af%d\n", ifp->if_xname,
			dst->sa_family);
		senderr(EAFNOSUPPORT);
	}

	if (mcopy)
		(void) looutput(ifp, mcopy, dst, rt);

	/*
	 * Add local net header.  If no space in first mbuf,
	 * allocate another.
	 */
	M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
	if (m == 0)
		senderr(ENOBUFS);
	eh = mtod(m, struct ether_header *);
	bcopy((caddr_t)&etype,(caddr_t)&eh->ether_type,
		sizeof(eh->ether_type));
 	bcopy((caddr_t)edst, (caddr_t)eh->ether_dhost, sizeof (edst));
	if (hdrcmplt)
		bcopy((caddr_t)esrc, (caddr_t)eh->ether_shost,
		    sizeof(eh->ether_shost));
	else
	 	bcopy(LLADDR(ifp->if_sadl), (caddr_t)eh->ether_shost,
		    sizeof(eh->ether_shost));
	s = splimp();
	/*
	 * Queue message on interface, and start output if interface
	 * not yet active.
	 */
	if (IF_QFULL(&ifp->if_snd)) {
		IF_DROP(&ifp->if_snd);
		splx(s);
		senderr(ENOBUFS);
	}
	ifp->if_obytes += m->m_pkthdr.len;
	IF_ENQUEUE(&ifp->if_snd, m);
	if ((ifp->if_flags & IFF_OACTIVE) == 0)
		(*ifp->if_start)(ifp);
	splx(s);
	if (m->m_flags & M_MCAST)
		ifp->if_omcasts++;
	return (error);

bad:
	if (m)
		m_freem(m);
	return (error);
}

/*
 * Process a received Ethernet packet;
 * the packet is in the mbuf chain m without
 * the ether header, which is provided separately.
 */
void
ether_input(ifp, eh, m)
	struct ifnet *ifp;
	struct ether_header *eh;
	struct mbuf *m;
{
	struct ifqueue *inq;
	u_int16_t etype;
	int s;
#if defined (ISO) || defined (LLC) || defined(NETATALK)
	struct llc *l;
#endif

	if ((ifp->if_flags & IFF_UP) == 0) {
		m_freem(m);
		return;
	}
	ifp->if_lastchange = time;
	ifp->if_ibytes += m->m_pkthdr.len + sizeof (*eh);
	if (eh->ether_dhost[0] & 1) {
		if (bcmp((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
		    sizeof(etherbroadcastaddr)) == 0)
			m->m_flags |= M_BCAST;
		else
			m->m_flags |= M_MCAST;
	}
	if (m->m_flags & (M_BCAST|M_MCAST))
		ifp->if_imcasts++;

	etype = ntohs(eh->ether_type);
	switch (etype) {
#ifdef INET
	case ETHERTYPE_IP:
#ifdef GATEWAY
		if (ipflow_fastforward(m))
			return;
#endif
		schednetisr(NETISR_IP);
		inq = &ipintrq;
		break;

	case ETHERTYPE_ARP:
		schednetisr(NETISR_ARP);
		inq = &arpintrq;
		break;

	case ETHERTYPE_REVARP:
		revarpinput(m);	/* XXX queue? */
		return;
#endif
#ifdef NS
	case ETHERTYPE_NS:
		schednetisr(NETISR_NS);
		inq = &nsintrq;
		break;

#endif
#ifdef IPX
	case ETHERTYPE_IPX:
		schednetisr(NETISR_IPX);
		inq = &ipxintrq;
		break;
#endif
#ifdef NETATALK
        case ETHERTYPE_ATALK:
                schednetisr(NETISR_ATALK);
                inq = &atintrq1;
                break;
        case ETHERTYPE_AARP:
		/* probably this should be done with a NETISR as well */
                aarpinput(ifp, m); /* XXX */
                return;
#endif /* NETATALK */
	default:
#if defined (ISO) || defined (LLC) || defined (NETATALK)
		if (etype > ETHERMTU)
			goto dropanyway;
		l = mtod(m, struct llc *);
		switch (l->llc_dsap) {
#ifdef NETATALK
		case LLC_SNAP_LSAP:
			switch (l->llc_control) {
			case LLC_UI:
				if (l->llc_ssap != LLC_SNAP_LSAP) {
					goto dropanyway;
				}
	    
				if (Bcmp(&(l->llc_snap_org_code)[0],
				    at_org_code, sizeof(at_org_code)) == 0 &&
				    ntohs(l->llc_snap_ether_type) ==
				    ETHERTYPE_ATALK) {
					inq = &atintrq2;
					m_adj(m, sizeof(struct llc));
					schednetisr(NETISR_ATALK);
					break;
				}

				if (Bcmp(&(l->llc_snap_org_code)[0],
				    aarp_org_code,
				    sizeof(aarp_org_code)) == 0 &&
				    ntohs(l->llc_snap_ether_type) ==
				    ETHERTYPE_AARP) {
					m_adj( m, sizeof(struct llc));
					aarpinput(ifp, m); /* XXX */
				    return;
				}
		    
			default:
				goto dropanyway;
			}
			break;
#endif /* NETATALK */
#ifdef	ISO
		case LLC_ISO_LSAP: 
			switch (l->llc_control) {
			case LLC_UI:
				/* LLC_UI_P forbidden in class 1 service */
				if ((l->llc_dsap == LLC_ISO_LSAP) &&
				    (l->llc_ssap == LLC_ISO_LSAP)) {
					/* LSAP for ISO */
					if (m->m_pkthdr.len > etype)
						m_adj(m, etype - m->m_pkthdr.len);
					m->m_data += 3;		/* XXX */
					m->m_len -= 3;		/* XXX */
					m->m_pkthdr.len -= 3;	/* XXX */
					M_PREPEND(m, sizeof *eh, M_DONTWAIT);
					if (m == 0)
						return;
					*mtod(m, struct ether_header *) = *eh;
#ifdef ARGO_DEBUG
					if (argo_debug[D_ETHER])
						printf("clnp packet");
#endif
					schednetisr(NETISR_ISO);
					inq = &clnlintrq;
					break;
				}
				goto dropanyway;
				
			case LLC_XID:
			case LLC_XID_P:
				if(m->m_len < 6)
					goto dropanyway;
				l->llc_window = 0;
				l->llc_fid = 9;
				l->llc_class = 1;
				l->llc_dsap = l->llc_ssap = 0;
				/* Fall through to */
			case LLC_TEST:
			case LLC_TEST_P:
			{
				struct sockaddr sa;
				struct ether_header *eh2;
				int i;
				u_char c = l->llc_dsap;

				l->llc_dsap = l->llc_ssap;
				l->llc_ssap = c;
				if (m->m_flags & (M_BCAST | M_MCAST))
					bcopy(LLADDR(ifp->if_sadl),
					      (caddr_t)eh->ether_dhost, 6);
				sa.sa_family = AF_UNSPEC;
				sa.sa_len = sizeof(sa);
				eh2 = (struct ether_header *)sa.sa_data;
				for (i = 0; i < 6; i++) {
					eh2->ether_shost[i] = c = 
					    eh->ether_dhost[i];
					eh2->ether_dhost[i] = 
					    eh->ether_dhost[i] =
					    eh->ether_shost[i];
					eh->ether_shost[i] = c;
				}
				ifp->if_output(ifp, m, &sa, NULL);
				return;
			}
			default:
				m_freem(m);
				return;
			}
			break;
#endif /* ISO */
#ifdef LLC
		case LLC_X25_LSAP:
		{
			if (m->m_pkthdr.len > etype)
				m_adj(m, etype - m->m_pkthdr.len);
			M_PREPEND(m, sizeof(struct sdl_hdr) , M_DONTWAIT);
			if (m == 0)
				return;
			if ( !sdl_sethdrif(ifp, eh->ether_shost, LLC_X25_LSAP,
					    eh->ether_dhost, LLC_X25_LSAP, 6, 
					    mtod(m, struct sdl_hdr *)))
				panic("ETHER cons addr failure");
			mtod(m, struct sdl_hdr *)->sdlhdr_len = etype;
#ifdef LLC_DEBUG
				printf("llc packet\n");
#endif /* LLC_DEBUG */
			schednetisr(NETISR_CCITT);
			inq = &llcintrq;
			break;
		}
#endif /* LLC */
		dropanyway:
		default:
			m_freem(m);
			return;
		}
#else /* ISO || LLC  || NETATALK*/
	    m_freem(m);
	    return;
#endif /* ISO || LLC || NETATALK*/
	}

	s = splimp();
	if (IF_QFULL(inq)) {
		IF_DROP(inq);
		m_freem(m);
	} else
		IF_ENQUEUE(inq, m);
	splx(s);
}

/*
 * Convert Ethernet address to printable (loggable) representation.
 */
static char digits[] = "0123456789abcdef";
char *
ether_sprintf(ap)
	u_char *ap;
{
	static char etherbuf[18];
	char *cp = etherbuf;
	int i;

	for (i = 0; i < 6; i++) {
		*cp++ = digits[*ap >> 4];
		*cp++ = digits[*ap++ & 0xf];
		*cp++ = ':';
	}
	*--cp = 0;
	return (etherbuf);
}

/*
 * Perform common duties while attaching to interface list
 */
void
ether_ifattach(ifp, lla)
	struct ifnet *ifp;
	u_int8_t * lla;
{
	struct sockaddr_dl *sdl;

	ifp->if_type = IFT_ETHER;
	ifp->if_addrlen = 6;
	ifp->if_hdrlen = 14;
	ifp->if_mtu = ETHERMTU;
	ifp->if_output = ether_output;
	if ((sdl = ifp->if_sadl) &&
	    sdl->sdl_family == AF_LINK) {
		sdl->sdl_type = IFT_ETHER;
		sdl->sdl_alen = ifp->if_addrlen;
		bcopy((caddr_t)lla, LLADDR(sdl), ifp->if_addrlen);
	}
	LIST_INIT(&((struct ethercom *)ifp)->ec_multiaddrs);
	ifp->if_broadcastaddr = etherbroadcastaddr;
}

u_char	ether_ipmulticast_min[6] = { 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
u_char	ether_ipmulticast_max[6] = { 0x01, 0x00, 0x5e, 0x7f, 0xff, 0xff };
/*
 * Add an Ethernet multicast address or range of addresses to the list for a
 * given interface.
 */
int
ether_addmulti(ifr, ec)
	struct ifreq *ifr;
	struct ethercom *ec;
{
	struct ether_multi *enm;
#ifdef INET
	struct sockaddr_in *sin;
#endif /* INET */
	u_char addrlo[6];
	u_char addrhi[6];
	int s = splimp();

	switch (ifr->ifr_addr.sa_family) {

	case AF_UNSPEC:
		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
		bcopy(addrlo, addrhi, 6);
		break;

#ifdef INET
	case AF_INET:
		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
		if (sin->sin_addr.s_addr == INADDR_ANY) {
			/*
			 * An IP address of INADDR_ANY means listen to all
			 * of the Ethernet multicast addresses used for IP.
			 * (This is for the sake of IP multicast routers.)
			 */
			bcopy(ether_ipmulticast_min, addrlo, 6);
			bcopy(ether_ipmulticast_max, addrhi, 6);
		}
		else {
			ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
			bcopy(addrlo, addrhi, 6);
		}
		break;
#endif

	default:
		splx(s);
		return (EAFNOSUPPORT);
	}

	/*
	 * Verify that we have valid Ethernet multicast addresses.
	 */
	if ((addrlo[0] & 0x01) != 1 || (addrhi[0] & 0x01) != 1) {
		splx(s);
		return (EINVAL);
	}
	/*
	 * See if the address range is already in the list.
	 */
	ETHER_LOOKUP_MULTI(addrlo, addrhi, ec, enm);
	if (enm != NULL) {
		/*
		 * Found it; just increment the reference count.
		 */
		++enm->enm_refcount;
		splx(s);
		return (0);
	}
	/*
	 * New address or range; malloc a new multicast record
	 * and link it into the interface's multicast list.
	 */
	enm = (struct ether_multi *)malloc(sizeof(*enm), M_IFMADDR, M_NOWAIT);
	if (enm == NULL) {
		splx(s);
		return (ENOBUFS);
	}
	bcopy(addrlo, enm->enm_addrlo, 6);
	bcopy(addrhi, enm->enm_addrhi, 6);
	enm->enm_ec = ec;
	enm->enm_refcount = 1;
	LIST_INSERT_HEAD(&ec->ec_multiaddrs, enm, enm_list);
	ec->ec_multicnt++;
	splx(s);
	/*
	 * Return ENETRESET to inform the driver that the list has changed
	 * and its reception filter should be adjusted accordingly.
	 */
	return (ENETRESET);
}

/*
 * Delete a multicast address record.
 */
int
ether_delmulti(ifr, ec)
	struct ifreq *ifr;
	struct ethercom *ec;
{
	struct ether_multi *enm;
#ifdef INET
	struct sockaddr_in *sin;
#endif /* INET */
	u_char addrlo[6];
	u_char addrhi[6];
	int s = splimp();

	switch (ifr->ifr_addr.sa_family) {

	case AF_UNSPEC:
		bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
		bcopy(addrlo, addrhi, 6);
		break;

#ifdef INET
	case AF_INET:
		sin = (struct sockaddr_in *)&(ifr->ifr_addr);
		if (sin->sin_addr.s_addr == INADDR_ANY) {
			/*
			 * An IP address of INADDR_ANY means stop listening
			 * to the range of Ethernet multicast addresses used
			 * for IP.
			 */
			bcopy(ether_ipmulticast_min, addrlo, 6);
			bcopy(ether_ipmulticast_max, addrhi, 6);
		}
		else {
			ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
			bcopy(addrlo, addrhi, 6);
		}
		break;
#endif

	default:
		splx(s);
		return (EAFNOSUPPORT);
	}

	/*
	 * Look up the address in our list.
	 */
	ETHER_LOOKUP_MULTI(addrlo, addrhi, ec, enm);
	if (enm == NULL) {
		splx(s);
		return (ENXIO);
	}
	if (--enm->enm_refcount != 0) {
		/*
		 * Still some claims to this record.
		 */
		splx(s);
		return (0);
	}
	/*
	 * No remaining claims to this record; unlink and free it.
	 */
	LIST_REMOVE(enm, enm_list);
	free(enm, M_IFMADDR);
	ec->ec_multicnt--;
	splx(s);
	/*
	 * Return ENETRESET to inform the driver that the list has changed
	 * and its reception filter should be adjusted accordingly.
	 */
	return (ENETRESET);
}