ether_mod-2.4.c

来自「网络通讯的源代码」· C语言 代码 · 共 379 行

/*
 *  $Id: ether_mod-2.4.c,v 1.2 1999/10/27 01:37:26 route Exp $
 *
 *  libnet
 *  OpenBSD 2.4 ether_mod.c - lkm replacement for ether_output
 *
 *  Copyright (c) 1998, 1999, 2000 Mike D. Schiffman <[e-mail]>
 *
 *  Original code and idea 1997 Thomas Ptacek <[e-mail]>
 *  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.
 *
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 */

#define INET

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

#include <netccitt/x25.h>
#include <netccitt/pk.h>
#include <netccitt/pk_extern.h>
#include <netccitt/dll.h>
#include <netccitt/llc_var.h>

#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 */

#if defined(CCITT)
#include <sys/socketvar.h>
#endif

#define senderr(e) { error = (e); goto bad;}


int ether_output_spoof(register struct ifnet *, struct mbuf *,
                        struct sockaddr *, struct rtentry *);

/*
 * Ethernet output routine.
 * Encapsulate a packet of type family for the local net.
 * Assumes that ifp is actually pointer to arpcom structure.
 */
int
ether_output_spoof(ifp, m0, dst, rt0)
	register struct ifnet *ifp;
	struct mbuf *m0;
	struct sockaddr *dst;
	struct rtentry *rt0;
{
	u_int16_t etype;
	int s, error = 0;
 	u_char edst[6], esrc[6];
	register struct mbuf *m = m0;
	register struct rtentry *rt;
	struct mbuf *mcopy = (struct mbuf *)0;
	register struct ether_header *eh;
	struct arpcom *ac = (struct arpcom *)ifp;

	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--;
			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);
				if ((rt = rt->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 (!arpresolve(ac, 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);
                bcopy((caddr_t)ac->ac_enaddr,esrc,sizeof(esrc));
		break;
#endif
#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 = htons(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 NETATALK
	case AF_APPLETALK: {
		struct at_ifaddr *aa;

		if (!aarpresolve(ac, m, (struct sockaddr_at *)dst, edst)) {
#ifdef NETATALKDEBUG
			extern char *prsockaddr(struct sockaddr *);
			printf("aarpresolv: failed for %s\n", prsockaddr(dst));
#endif /* NETATALKDEBUG */
			return (0);
		}

		/*
		 * ifaddr is the first thing in at_ifaddr
		 */
		aa = (struct at_ifaddr *)at_ifawithnet(
			(struct sockaddr_at *)dst,
			ifp->if_addrlist.tqh_first);
		if (aa == 0)
			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;

			/* XXX Really this should use netisr too */
			M_PREPEND(m, AT_LLC_SIZE, M_WAIT);
			/*
			 * FreeBSD doesn't count the LLC len in
			 * ifp->obytes, so they increment a length
			 * field here. We don't do this.
			 */
			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), AT_LLC_SIZE);
			etype = htons(m->m_pkthdr.len);
		} else {
			etype = htons(ETHERTYPE_AT);
		}
		} break;
#endif /* NETATALK */
#ifdef	ISO
	case AF_ISO: {
		int	snpalen;
		struct	llc *l;
		register 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((caddr_t)ac->ac_enaddr,
				      (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 */
/*	case AF_NSAP: */
	case AF_CCITT: {
		register 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((caddr_t)ac->ac_enaddr,
				      (caddr_t)eh->ether_shost, sizeof (edst));
			}
		}
		etype = htons(m->m_pkthdr.len);
#ifdef LLC_DEBUG
		{
			int i;
			register 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;

	case AF_UNSPEC:
		eh = (struct ether_header *)dst->sa_data;
 		bcopy((caddr_t)eh->ether_dhost, (caddr_t)edst, sizeof (edst));
                bcopy((caddr_t)eh->ether_shost, (caddr_t)esrc, sizeof (esrc));
		/* 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));
 	bcopy((caddr_t)esrc, (caddr_t)eh->ether_shost, sizeof (esrc));

	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 (m->m_flags & M_MCAST)
		ifp->if_omcasts++;
	if ((ifp->if_flags & IFF_OACTIVE) == 0)
		(*ifp->if_start)(ifp);
	splx(s);
	return (error);

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