freebsd/sys/netipx/ipx_input.c

/*
 * Copyright (c) 1995, Mike Mitchell
 * Copyright (c) 1984, 1985, 1986, 1987, 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.
 *
 *	@(#)ipx_input.c
 *
 * $Id: ipx_input.c,v 1.17 1998/04/06 09:30:42 phk Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/route.h>
#include <net/netisr.h>

#include <netipx/ipx.h>
#include <netipx/spx.h>
#include <netipx/ipx_if.h>
#include <netipx/ipx_pcb.h>
#include <netipx/ipx_var.h>

#include <machine/random.h>

int	ipxcksum = 0;
SYSCTL_INT(_net_ipx_ipx, OID_AUTO, checksum, CTLFLAG_RW,
	   &ipxcksum, 0, "");

static int	ipxprintfs = 0;		/* printing forwarding information */
SYSCTL_INT(_net_ipx_ipx, OID_AUTO, ipxprintfs, CTLFLAG_RW,
	   &ipxprintfs, 0, "");

static int	ipxforwarding = 0;
SYSCTL_INT(_net_ipx_ipx, OID_AUTO, ipxforwarding, CTLFLAG_RW,
	    &ipxforwarding, 0, "");

static int	ipxnetbios = 0;
SYSCTL_INT(_net_ipx, OID_AUTO, ipxnetbios, CTLFLAG_RW,
	   &ipxnetbios, 0, "");

union	ipx_net ipx_zeronet;
union	ipx_host ipx_zerohost;

union	ipx_net	ipx_broadnet;
union	ipx_host ipx_broadhost;

struct	ipxstat ipxstat;
struct	sockaddr_ipx ipx_netmask, ipx_hostmask;

static	u_short allones[] = {-1, -1, -1};

struct	ipxpcb ipxpcb;
struct	ipxpcb ipxrawpcb;

struct	ifqueue	ipxintrq;
static int ipxqmaxlen = IFQ_MAXLEN;

long	ipx_pexseq;

NETISR_SET(NETISR_IPX, ipxintr);

static	int ipx_do_route(struct ipx_addr *src, struct route *ro);
static	void ipx_undo_route(struct route *ro);
static	void ipx_forward(struct mbuf *m);

/*
 * IPX initialization.
 */

void
ipx_init()
{
	ipx_broadnet = *(union ipx_net *)allones;
	ipx_broadhost = *(union ipx_host *)allones;

	read_random(&ipx_pexseq, sizeof ipx_pexseq);
	ipxintrq.ifq_maxlen = ipxqmaxlen;
	ipxpcb.ipxp_next = ipxpcb.ipxp_prev = &ipxpcb;
	ipxrawpcb.ipxp_next = ipxrawpcb.ipxp_prev = &ipxrawpcb;

	ipx_netmask.sipx_len = 6;
	ipx_netmask.sipx_addr.x_net = ipx_broadnet;

	ipx_hostmask.sipx_len = 12;
	ipx_hostmask.sipx_addr.x_net = ipx_broadnet;
	ipx_hostmask.sipx_addr.x_host = ipx_broadhost;
}

/*
 * IPX input routine.  Pass to next level.
 */
void
ipxintr()
{
	register struct ipx *ipx;
	register struct mbuf *m;
	register struct ipxpcb *ipxp;
	struct ipx_ifaddr *ia;
	register int i;
	int len, s;
	char oddshortpacket = 0;

next:
	/*
	 * Get next datagram off input queue and get IPX header
	 * in first mbuf.
	 */
	s = splimp();
	IF_DEQUEUE(&ipxintrq, m);
	splx(s);
	if (m == NULL)
		return;
	/*
	 * If no IPX addresses have been set yet but the interfaces
	 * are receiving, can't do anything with incoming packets yet.
	 */
	if (ipx_ifaddr == NULL)
		goto bad;

	ipxstat.ipxs_total++;

	if ((m->m_flags & M_EXT || m->m_len < sizeof(struct ipx)) &&
	    (m = m_pullup(m, sizeof(struct ipx))) == 0) {
		ipxstat.ipxs_toosmall++;
		goto next;
	}

	/*
	 * Give any raw listeners a crack at the packet
	 */
	for (ipxp = ipxrawpcb.ipxp_next; ipxp != &ipxrawpcb;
	     ipxp = ipxp->ipxp_next) {
		struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL);
		if (m1 != NULL)
			ipx_input(m1, ipxp);
	}

	ipx = mtod(m, struct ipx *);
	len = ntohs(ipx->ipx_len);
	if ((len < m->m_pkthdr.len) && (oddshortpacket = len & 1)) {
		/*
		 * If this packet is of odd length, and the length
		 * inside the header is less than the received packet
		 * length, preserve garbage byte for possible checksum.
		 */
		len++;
	}

	/*
	 * Check that the amount of data in the buffers
	 * is as at least much as the IPX header would have us expect.
	 * Trim mbufs if longer than we expect.
	 * Drop packet if shorter than we expect.
	 */
	if (m->m_pkthdr.len < len) {
		ipxstat.ipxs_tooshort++;
		goto bad;
	}
	if (m->m_pkthdr.len > len) {
		if (m->m_len == m->m_pkthdr.len) {
			m->m_len = len;
			m->m_pkthdr.len = len;
		} else
			m_adj(m, len - m->m_pkthdr.len);
	}
	if (ipxcksum && ((i = ipx->ipx_sum) != 0xffff)) {
		ipx->ipx_sum = 0;
		if (i != (ipx->ipx_sum = ipx_cksum(m, len))) {
			ipxstat.ipxs_badsum++;
			goto bad;
		}
	}

	/*
	 * Propagated (Netbios) packets (type 20) has to be handled
	 * different. :-(
	 */
	if (ipx->ipx_pt == IPXPROTO_NETBIOS) {
		if (ipxnetbios) {
			ipx_output_type20(m);
			goto next;
		} else
			goto bad;
	}

	/*
	 * Is this a directed broadcast?
	 */
	if (ipx_hosteqnh(ipx_broadhost,ipx->ipx_dna.x_host)) {
		if ((!ipx_neteq(ipx->ipx_dna, ipx->ipx_sna)) &&
		    (!ipx_neteqnn(ipx->ipx_dna.x_net, ipx_broadnet)) &&
		    (!ipx_neteqnn(ipx->ipx_sna.x_net, ipx_zeronet)) &&
		    (!ipx_neteqnn(ipx->ipx_dna.x_net, ipx_zeronet)) ) {
			/*
			 * If it is a broadcast to the net where it was
			 * received from, treat it as ours.
			 */
			for (ia = ipx_ifaddr; ia != NULL; ia = ia->ia_next)
				if((ia->ia_ifa.ifa_ifp == m->m_pkthdr.rcvif) &&
				   ipx_neteq(ia->ia_addr.sipx_addr, 
					     ipx->ipx_dna))
					goto ours;

			/*
			 * Look to see if I need to eat this packet.
			 * Algorithm is to forward all young packets
			 * and prematurely age any packets which will
			 * by physically broadcasted.
			 * Any very old packets eaten without forwarding
			 * would die anyway.
			 *
			 * Suggestion of Bill Nesheim, Cornell U.
			 */
			if (ipx->ipx_tc < IPX_MAXHOPS) {
				ipx_forward(m);
				goto next;
			}
		}
	/*
	 * Is this our packet? If not, forward.
	 */
	} else {
		for (ia = ipx_ifaddr; ia != NULL; ia = ia->ia_next)
			if (ipx_hosteq(ipx->ipx_dna, ia->ia_addr.sipx_addr) &&
			    (ipx_neteq(ipx->ipx_dna, ia->ia_addr.sipx_addr) ||
			     ipx_neteqnn(ipx->ipx_dna.x_net, ipx_zeronet)))
				break;

		if (ia == NULL) {
			ipx_forward(m);
			goto next;
		}
	}
ours:
	/*
	 * Locate pcb for datagram.
	 */
	ipxp = ipx_pcblookup(&ipx->ipx_sna, ipx->ipx_dna.x_port, IPX_WILDCARD);
	/*
	 * Switch out to protocol's input routine.
	 */
	if (ipxp != NULL) {
		if (oddshortpacket) {
			m_adj(m, -1);
		}
		ipxstat.ipxs_delivered++;
		if ((ipxp->ipxp_flags & IPXP_ALL_PACKETS) == 0)
			switch (ipx->ipx_pt) {

			    case IPXPROTO_SPX:
				    spx_input(m, ipxp);
				    goto next;
			}
		ipx_input(m, ipxp);
	} else
		goto bad;

	goto next;

bad:
	m_freem(m);
	goto next;
}

void
ipx_ctlinput(cmd, arg_as_sa, dummy)
	int cmd;
	struct sockaddr *arg_as_sa;	/* XXX should be swapped with dummy */
	void *dummy;
{
	caddr_t arg = (/* XXX */ caddr_t)arg_as_sa;
	struct ipx_addr *ipx;

	if (cmd < 0 || cmd > PRC_NCMDS)
		return;
	switch (cmd) {
		struct sockaddr_ipx *sipx;

	case PRC_IFDOWN:
	case PRC_HOSTDEAD:
	case PRC_HOSTUNREACH:
		sipx = (struct sockaddr_ipx *)arg;
		if (sipx->sipx_family != AF_IPX)
			return;
		ipx = &sipx->sipx_addr;
		break;

	default:
		if (ipxprintfs)
			printf("ipx_ctlinput: cmd %d.\n", cmd);
		break;
	}
}

/*
 * Forward a packet. If some error occurs drop the packet. IPX don't
 * have a way to return errors to the sender.
 */

static struct route ipx_droute;
static struct route ipx_sroute;

static void
ipx_forward(m)
struct mbuf *m;
{
	register struct ipx *ipx = mtod(m, struct ipx *);
	register int error;
	struct mbuf *mcopy = NULL;
	int agedelta = 1;
	int flags = IPX_FORWARDING;
	int ok_there = 0;
	int ok_back = 0;

	if (ipxforwarding == 0) {
		/* can't tell difference between net and host */
		ipxstat.ipxs_cantforward++;
		m_freem(m);
		goto cleanup;
	}
	ipx->ipx_tc++;
	if (ipx->ipx_tc > IPX_MAXHOPS) {
		ipxstat.ipxs_cantforward++;
		m_freem(m);
		goto cleanup;
	}

	if ((ok_there = ipx_do_route(&ipx->ipx_dna,&ipx_droute)) == 0) {
		ipxstat.ipxs_noroute++;
		m_freem(m);
		goto cleanup;
	}
	/*
	 * Here we think about  forwarding  broadcast packets,
	 * so we try to insure that it doesn't go back out
	 * on the interface it came in on.  Also, if we
	 * are going to physically broadcast this, let us
	 * age the packet so we can eat it safely the second time around.
	 */
	if (ipx->ipx_dna.x_host.c_host[0] & 0x1) {
		struct ipx_ifaddr *ia = ipx_iaonnetof(&ipx->ipx_dna);
		struct ifnet *ifp;
		if (ia != NULL) {
			/* I'm gonna hafta eat this packet */
			agedelta += IPX_MAXHOPS - ipx->ipx_tc;
			ipx->ipx_tc = IPX_MAXHOPS;
		}
		if ((ok_back = ipx_do_route(&ipx->ipx_sna,&ipx_sroute)) == 0) {
			/* error = ENETUNREACH; He'll never get it! */
			ipxstat.ipxs_noroute++;
			m_freem(m);
			goto cleanup;
		}
		if (ipx_droute.ro_rt &&
		    (ifp = ipx_droute.ro_rt->rt_ifp) &&
		    ipx_sroute.ro_rt &&
		    (ifp != ipx_sroute.ro_rt->rt_ifp)) {
			flags |= IPX_ALLOWBROADCAST;
		} else {
			ipxstat.ipxs_noroute++;
			m_freem(m);
			goto cleanup;
		}
	}
	/* XXX
	 * I think the checksum generation is bogus. According to the NLSP
	 * spec the ipx_tc (hop count) field and the ipx_sum should be
	 * zero'ed before generating the checksum, ie. it should not be
	 * necesary to recompute it in the forwarding function.
	 */
	/* need to adjust checksum */
	if (ipxcksum && ipx->ipx_sum != 0xffff) {
		union bytes {
			u_char c[4];
			u_short s[2];
			long l;
		} x;
		register int shift;
		x.l = 0;
		x.c[0] = agedelta;
		shift = (((((int)ntohs(ipx->ipx_len)) + 1) >> 1) - 2) & 0xf;
		x.l = ipx->ipx_sum + (x.s[0] << shift);
		x.l = x.s[0] + x.s[1];
		x.l = x.s[0] + x.s[1];
		if (x.l == 0xffff)
			ipx->ipx_sum = 0;
		else
			ipx->ipx_sum = x.l;
	} else 
		ipx->ipx_sum = 0xffff;

	error = ipx_outputfl(m, &ipx_droute, flags);
	if (error == 0) {
		ipxstat.ipxs_forward++;

		if (ipxprintfs) {
			printf("forward: ");
			ipx_printhost(&ipx->ipx_sna);
			printf(" to ");
			ipx_printhost(&ipx->ipx_dna);
			printf(" hops %d\n", ipx->ipx_tc);
		}
	} else if (mcopy != NULL) {
		ipx = mtod(mcopy, struct ipx *);
		switch (error) {

		case ENETUNREACH:
		case EHOSTDOWN:
		case EHOSTUNREACH:
		case ENETDOWN:
		case EPERM:
			ipxstat.ipxs_noroute++;
			break;

		case EMSGSIZE:
			ipxstat.ipxs_mtutoosmall++;
			break;

		case ENOBUFS:
			ipxstat.ipxs_odropped++;
			break;
		}
		mcopy = NULL;
		m_freem(m);
	}
cleanup:
	if (ok_there)
		ipx_undo_route(&ipx_droute);
	if (ok_back)
		ipx_undo_route(&ipx_sroute);
	if (mcopy != NULL)
		m_freem(mcopy);
}

static int
ipx_do_route(src, ro)
struct ipx_addr *src;
struct route *ro;
{
	struct sockaddr_ipx *dst;

	bzero((caddr_t)ro, sizeof(*ro));
	dst = (struct sockaddr_ipx *)&ro->ro_dst;

	dst->sipx_len = sizeof(*dst);
	dst->sipx_family = AF_IPX;
	dst->sipx_addr = *src;
	dst->sipx_addr.x_port = 0;
	rtalloc(ro);
	if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp == NULL) {
		return (0);
	}
	ro->ro_rt->rt_use++;
	return (1);
}

static void
ipx_undo_route(ro)
register struct route *ro;
{
	if (ro->ro_rt != NULL) {
		RTFREE(ro->ro_rt);
	}
}

void
ipx_watch_output(m, ifp)
struct mbuf *m;
struct ifnet *ifp;
{
	register struct ipxpcb *ipxp;
	register struct ifaddr *ifa;
	register struct ipx_ifaddr *ia;
	/*
	 * Give any raw listeners a crack at the packet
	 */
	for (ipxp = ipxrawpcb.ipxp_next; ipxp != &ipxrawpcb;
	     ipxp = ipxp->ipxp_next) {
		struct mbuf *m0 = m_copy(m, 0, (int)M_COPYALL);
		if (m0 != NULL) {
			register struct ipx *ipx;

			M_PREPEND(m0, sizeof(*ipx), M_DONTWAIT);
			if (m0 == NULL)
				continue;
			ipx = mtod(m0, struct ipx *);
			ipx->ipx_sna.x_net = ipx_zeronet;
			for (ia = ipx_ifaddr; ia != NULL; ia = ia->ia_next)
				if (ifp == ia->ia_ifp)
					break;
			if (ia == NULL)
				ipx->ipx_sna.x_host = ipx_zerohost;  
			else 
				ipx->ipx_sna.x_host =
				    ia->ia_addr.sipx_addr.x_host;

			if (ifp != NULL && (ifp->if_flags & IFF_POINTOPOINT))
			    for(ifa = ifp->if_addrhead.tqh_first; ifa != NULL;
						ifa = ifa->ifa_link.tqe_next) {
				if (ifa->ifa_addr->sa_family == AF_IPX) {
				    ipx->ipx_sna = IA_SIPX(ifa)->sipx_addr;
				    break;
				}
			    }
			ipx->ipx_len = ntohl(m0->m_pkthdr.len);
			ipx_input(m0, ipxp);
		}
	}
}