if_ethersubr.c

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//==========================================================================
//
//      src/sys/net/if_ethersubr.c
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// Portions created by Red Hat are
// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*
 * 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	8.1 (Berkeley) 6/10/93
 * $FreeBSD: src/sys/net/if_ethersubr.c,v 1.70.2.17 2001/08/01 00:47:49 fenner Exp $
 */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>

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

#if defined(INET) || defined(INET6)
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/if_ether.h>
#endif
#ifdef INET6
#include <netinet6/nd6.h>
#endif

#ifdef IPX
#include <netipx/ipx.h>
#include <netipx/ipx_if.h>
int (*ef_inputp)(struct ifnet*, struct ether_header *eh, struct mbuf *m);
int (*ef_outputp)(struct ifnet *ifp, struct mbuf **mp,
		struct sockaddr *dst, short *tp, int *hlen);
#endif

#ifdef NS
#include <netns/ns.h>
#include <netns/ns_if.h>
ushort ns_nettype;
int ether_outputdebug = 0;
int ether_inputdebug = 0;
#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 */

#ifdef BRIDGE
#include <net/bridge.h>
#endif

#define NVLAN 0
#if NVLAN > 0
#include <net/if_vlan_var.h>
#endif /* NVLAN > 0 */

/* netgraph node hooks for ng_ether(4) */
void	(*ng_ether_input_p)(struct ifnet *ifp,
		struct mbuf **mp, struct ether_header *eh);
void	(*ng_ether_input_orphan_p)(struct ifnet *ifp,
		struct mbuf *m, struct ether_header *eh);
int	(*ng_ether_output_p)(struct ifnet *ifp, struct mbuf **mp);
void	(*ng_ether_attach_p)(struct ifnet *ifp);
void	(*ng_ether_detach_p)(struct ifnet *ifp);

static	int ether_resolvemulti __P((struct ifnet *, struct sockaddr **,
				    struct sockaddr *));
u_char	etherbroadcastaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
#define senderr(e) do { error = (e); goto bad;} while (0)
#define IFP2AC(IFP) ((struct arpcom *)IFP)

/*
 * Ethernet output routine.
 * Encapsulate a packet of type family for the local net.
 * Use trailer local net encapsulation if enough data in first
 * packet leaves a multiple of 512 bytes of data in remainder.
 * Assumes that ifp is actually pointer to arpcom structure.
 */
int
ether_output(ifp, m, dst, rt0)
	register struct ifnet *ifp;
	struct mbuf *m;
	struct sockaddr *dst;
	struct rtentry *rt0;
{
	short type;
	int error = 0, hdrcmplt = 0;
 	u_char esrc[6], edst[6];
	register struct rtentry *rt;
	register struct ether_header *eh;
	int off, loop_copy = 0;
	int hlen;	/* link layer header lenght */
	struct arpcom *ac = IFP2AC(ifp);

	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
		senderr(ENETDOWN);
	rt = rt0;
	if (rt) {
		if ((rt->rt_flags & RTF_UP) == 0) {
			rt0 = rt = rtalloc1(dst, 1, 0UL);
			if (rt0)
				rt->rt_refcnt--;
			else
				senderr(EHOSTUNREACH);
		}
		if (rt->rt_flags & RTF_GATEWAY) {
			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,
							  0UL);
				if ((rt = rt->rt_gwroute) == 0)
					senderr(EHOSTUNREACH);
			}
		}
		if (rt->rt_flags & RTF_REJECT)
			if (rt->rt_rmx.rmx_expire == 0 ||
			    time_second < rt->rt_rmx.rmx_expire)
				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
	}
	hlen = ETHER_HDR_LEN;
	switch (dst->sa_family) {
#ifdef INET
	case AF_INET:
		if (!arpresolve(ac, rt, m, dst, edst, rt0))
			return (0);	/* if not yet resolved */
		off = m->m_pkthdr.len - m->m_len;
		type = htons(ETHERTYPE_IP);
		break;
#endif
#ifdef INET6
	case AF_INET6:
		if (!nd6_storelladdr(&ac->ac_if, rt, m, dst, (u_char *)edst)) {
			/* Something bad happened */
			return(0);
		}
		off = m->m_pkthdr.len - m->m_len;
		type = htons(ETHERTYPE_IPV6);
		break;
#endif
#ifdef IPX
	case AF_IPX:
		if (ef_outputp) {
		    error = ef_outputp(ifp, &m, dst, &type, &hlen);
		    if (error)
			goto bad;
		} else
		    type = htons(ETHERTYPE_IPX);
 		bcopy((caddr_t)&(((struct sockaddr_ipx *)dst)->sipx_addr.x_host),
		    (caddr_t)edst, sizeof (edst));
		break;
#endif
#ifdef NETATALK
	case AF_APPLETALK:
	  {
	    struct at_ifaddr *aa;

	    if ((aa = at_ifawithnet((struct sockaddr_at *)dst)) == NULL) {
		    goto bad;
	    }
	    if (!aarpresolve(ac, m, (struct sockaddr_at *)dst, edst))
		    return (0);
	    /*
	     * In the phase 2 case, 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(at_org_code));
		llc.llc_snap_ether_type = htons( ETHERTYPE_AT );
		bcopy(&llc, mtod(m, caddr_t), sizeof(struct llc));
		type = htons(m->m_pkthdr.len);
		hlen = sizeof(struct llc) + ETHER_HDR_LEN;
	    } else {
		type = htons(ETHERTYPE_AT);
	    }
	    break;
	  }
#endif /* NETATALK */
#ifdef NS
	case AF_NS:
		switch(ns_nettype){
		default:
		case 0x8137: /* Novell Ethernet_II Ethernet TYPE II */
			type = 0x8137;
			break;
		case 0x0: /* Novell 802.3 */
			type = htons( m->m_pkthdr.len);
			break;
		case 0xe0e0: /* Novell 802.2 and Token-Ring */
			M_PREPEND(m, 3, M_WAIT);
			type = htons( m->m_pkthdr.len);
			cp = mtod(m, u_char *);
			*cp++ = 0xE0;
			*cp++ = 0xE0;
			*cp++ = 0x03;
			break;
		}
 		bcopy((caddr_t)&(((struct sockaddr_ns *)dst)->sns_addr.x_host),
		    (caddr_t)edst, sizeof (edst));
		/*
		 * XXX if ns_thishost is the same as the node's ethernet
		 * address then just the default code will catch this anyhow.
		 * So I'm not sure if this next clause should be here at all?
		 * [JRE]
		 */
		if (!bcmp((caddr_t)edst, (caddr_t)&ns_thishost, sizeof(edst))){
			m->m_pkthdr.rcvif = ifp;
			schednetisr(NETISR_NS);
			inq = &nsintrq;
			s = splimp();
			if (IF_QFULL(inq)) {
				IF_DROP(inq);
				m_freem(m);
			} else
				IF_ENQUEUE(inq, m);
			splx(s);
			return (error);
		}
		if (!bcmp((caddr_t)edst, (caddr_t)&ns_broadhost, sizeof(edst))){
			m->m_flags |= M_BCAST;
		}
		break;
#endif /* NS */

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

	case AF_UNSPEC:
		loop_copy = -1; /* if this is for us, don't do it */
		eh = (struct ether_header *)dst->sa_data;
 		(void)memcpy(edst, eh->ether_dhost, sizeof (edst));
		type = eh->ether_type;
		break;

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

	/*
	 * 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 *);
	(void)memcpy(&eh->ether_type, &type,
		sizeof(eh->ether_type));
 	(void)memcpy(eh->ether_dhost, edst, sizeof (edst));
	if (hdrcmplt)
		(void)memcpy(eh->ether_shost, esrc,
			sizeof(eh->ether_shost));
	else
		(void)memcpy(eh->ether_shost, ac->ac_enaddr,
			sizeof(eh->ether_shost));

	/*
	 * If a simplex interface, and the packet is being sent to our
	 * Ethernet address or a broadcast address, loopback a copy.
	 * XXX To make a simplex device behave exactly like a duplex
	 * device, we should copy in the case of sending to our own
	 * ethernet address (thus letting the original actually appear
	 * on the wire). However, we don't do that here for security
	 * reasons and compatibility with the original behavior.
	 */
	if ((ifp->if_flags & IFF_SIMPLEX) && (loop_copy != -1)) {
		if ((m->m_flags & M_BCAST) || (loop_copy > 0)) {
			struct mbuf *n = m_copy(m, 0, (int)M_COPYALL);
            
            if ( n == 0 ) {
                error = 0;
                goto bad;
            }

			(void) if_simloop(ifp, n, dst->sa_family, hlen);
		} else if (bcmp(eh->ether_dhost,
		    eh->ether_shost, ETHER_ADDR_LEN) == 0) {
			(void) if_simloop(ifp, m, dst->sa_family, hlen);
			return (0);	/* XXX */
		}
	}

	/* Handle ng_ether(4) processing, if any */
	if (ng_ether_output_p != NULL) {
		if ((error = (*ng_ether_output_p)(ifp, &m)) != 0) {
bad:			if (m != NULL)
				m_freem(m);
			return (error);
		}
		if (m == NULL)
			return (0);
	}

	/* Continue with link-layer output */
	return ether_output_frame(ifp, m);
}

/*
 * Ethernet link layer output routine to send a raw frame to the device.
 *
 * This assumes that the 14 byte Ethernet header is present and contiguous
 * in the first mbuf (if BRIDGE'ing).
 */
int
ether_output_frame(ifp, m)
	struct ifnet *ifp;
	struct mbuf *m;
{
	int s, len, error = 0;
	short mflags;
#ifdef ALTQ
	struct altq_pktattr pktattr;
#endif

#ifdef BRIDGE
	if (do_bridge && BDG_USED(ifp) ) {
		struct ether_header *eh; /* a ptr suffices */

		m->m_pkthdr.rcvif = NULL;
		eh = mtod(m, struct ether_header *);
		m_adj(m, ETHER_HDR_LEN);
		m = bdg_forward(m, eh, ifp);
		if (m != NULL)
			m_freem(m);
		return (0);
	}
#endif
#ifdef ALTQ
	if (ALTQ_IS_ENABLED(&ifp->if_snd))
		altq_etherclassify(&ifp->if_snd, m, &pktattr);
#endif
	mflags = m->m_flags;
	len = m->m_pkthdr.len;
	s = splimp();
	/*
	 * Queue message on interface, and start output if interface
	 * not yet active.
	 */
#ifdef ALTQ
	IFQ_ENQUEUE(&ifp->if_snd, m, &pktattr, error);
#else
	IFQ_ENQUEUE(&ifp->if_snd, m, error);
#endif
	if (error) {
		/* mbuf is already freed */
		splx(s);
		return (error);
	}
	ifp->if_obytes += len;
	if (mflags & M_MCAST)
		ifp->if_omcasts++;
	if ((ifp->if_flags & IFF_OACTIVE) == 0)
		(*ifp->if_start)(ifp);
	splx(s);
	return (error);
}

/*
 * Process a received Ethernet packet;
 * the packet is in the mbuf chain m without
 * the ether header, which is provided separately.
 *
 * First we perform any link layer operations, then continue
 * to the upper layers with ether_demux().
 */
void
ether_input(ifp, eh, m)
	struct ifnet *ifp;
	struct ether_header *eh;
	struct mbuf *m;
{
#ifdef BRIDGE
	struct ether_header save_eh;
#endif

#ifdef BPF
	/* Check for a BPF tap */
	if (ifp->if_bpf != NULL) {
		struct m_hdr mh;

		/* This kludge is OK; BPF treats the "mbuf" as read-only */
		mh.mh_next = m;
		mh.mh_data = (char *)eh;
		mh.mh_len = ETHER_HDR_LEN;
		bpf_mtap(ifp, (struct mbuf *)&mh);
	}
#endif

	/* Handle ng_ether(4) processing, if any */
	if (ng_ether_input_p != NULL) {
		(*ng_ether_input_p)(ifp, &m, eh);
		if (m == NULL)
			return;
	}

#ifdef BRIDGE
	/* Check for bridging mode */
	if (do_bridge && BDG_USED(ifp) ) {
		struct ifnet *bif;

		/* Check with bridging code */
		if ((bif = bridge_in(ifp, eh)) == BDG_DROP) {
			m_freem(m);
			return;