sys/netatalk/ddp_input.c

/*-
 * Copyright (c) 2004 Robert N. M. Watson
 * 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.
 */
/*-
 * Copyright (c) 1990,1994 Regents of The University of Michigan.
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby granted,
 * provided that the above copyright notice appears in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation, and that the name of The University
 * of Michigan not be used in advertising or publicity pertaining to
 * distribution of the software without specific, written prior
 * permission. This software is supplied as is without expressed or
 * implied warranties of any kind.
 *
 * This product includes software developed by the University of
 * California, Berkeley and its contributors.
 *
 *	Research Systems Unix Group
 *	The University of Michigan
 *	c/o Wesley Craig
 *	535 W. William Street
 *	Ann Arbor, Michigan
 *	+1-313-764-2278
 *	netatalk@umich.edu
 *
 * $FreeBSD: head/sys/netatalk/ddp_input.c 139827 2005-01-07 02:35:34Z imp $
 */

#include "opt_mac.h"

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mac.h>
#include <sys/mbuf.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sx.h>
#include <sys/systm.h>
#include <net/if.h>
#include <net/route.h>

#include <netatalk/at.h>
#include <netatalk/at_var.h>
#include <netatalk/ddp.h>
#include <netatalk/ddp_var.h>
#include <netatalk/ddp_pcb.h>
#include <netatalk/at_extern.h>

static volatile int	ddp_forward = 1;
static volatile int	ddp_firewall = 0;
static struct ddpstat	ddpstat;

static struct route	forwro;

static void     ddp_input(struct mbuf *, struct ifnet *, struct elaphdr *, int);

/*
 * Could probably merge these two code segments a little better...
 */
void
at2intr(struct mbuf *m)
{

	/*
	 * Phase 2 packet handling
	 */
	ddp_input(m, m->m_pkthdr.rcvif, NULL, 2);
	return;
}

void
at1intr(struct mbuf *m)
{
	struct elaphdr *elhp, elh;

	/*
	 * Phase 1 packet handling
	 */
	if (m->m_len < SZ_ELAPHDR && ((m = m_pullup(m, SZ_ELAPHDR)) == NULL)) {
		ddpstat.ddps_tooshort++;
		return;
	}

	/*
	 * This seems a little dubious, but I don't know phase 1 so leave it.
	 */
	elhp = mtod(m, struct elaphdr *);
	m_adj(m, SZ_ELAPHDR);

	if (elhp->el_type == ELAP_DDPEXTEND) {
		ddp_input(m, m->m_pkthdr.rcvif, NULL, 1);
	} else {
		bcopy((caddr_t)elhp, (caddr_t)&elh, SZ_ELAPHDR);
		ddp_input(m, m->m_pkthdr.rcvif, &elh, 1);
	}
	return;
}

static void
ddp_input(m, ifp, elh, phase)
    struct mbuf		*m;
    struct ifnet	*ifp;
    struct elaphdr	*elh;
    int			phase;
{
    struct sockaddr_at	from, to;
    struct ddpshdr	*dsh, ddps;
    struct at_ifaddr	*aa;
    struct ddpehdr	*deh = NULL, ddpe;
    struct ddpcb	*ddp;
    int			dlen, mlen;
    u_short		cksum = 0;

    bzero((caddr_t)&from, sizeof(struct sockaddr_at));
    bzero((caddr_t)&to, sizeof(struct sockaddr_at));
    if (elh != NULL) {
	/*
	 * Extract the information in the short header.
	 * netowrk information is defaulted to ATADDR_ANYNET
	 * and node information comes from the elh info.
	 * We must be phase 1.
	 */
	ddpstat.ddps_short++;

	if (m->m_len < sizeof(struct ddpshdr) &&
		((m = m_pullup(m, sizeof(struct ddpshdr))) == NULL)) {
	    ddpstat.ddps_tooshort++;
	    return;
	}

	dsh = mtod(m, struct ddpshdr *);
	bcopy((caddr_t)dsh, (caddr_t)&ddps, sizeof(struct ddpshdr));
	ddps.dsh_bytes = ntohl(ddps.dsh_bytes);
	dlen = ddps.dsh_len;

	to.sat_addr.s_net = ATADDR_ANYNET;
	to.sat_addr.s_node = elh->el_dnode;
	to.sat_port = ddps.dsh_dport;
	from.sat_addr.s_net = ATADDR_ANYNET;
	from.sat_addr.s_node = elh->el_snode;
	from.sat_port = ddps.dsh_sport;

	/*
	 * Make sure that we point to the phase1 ifaddr info
	 * and that it's valid for this packet.
	 */
	for (aa = at_ifaddr_list; aa != NULL; aa = aa->aa_next) {
	    if ((aa->aa_ifp == ifp)
	    && ((aa->aa_flags & AFA_PHASE2) == 0)
	    && ((to.sat_addr.s_node == AA_SAT(aa)->sat_addr.s_node)
	      || (to.sat_addr.s_node == ATADDR_BCAST))) {
		break;
	    }
	}
	/*
	 * maybe we got a broadcast not meant for us.. ditch it.
	 */
	if (aa == NULL) {
	    m_freem(m);
	    return;
	}
    } else {
	/*
	 * There was no 'elh' passed on. This could still be
	 * either phase1 or phase2.
	 * We have a long header, but we may be running on a phase 1 net.
	 * Extract out all the info regarding this packet's src & dst.
	 */
	ddpstat.ddps_long++;

	if (m->m_len < sizeof(struct ddpehdr) &&
		((m = m_pullup(m, sizeof(struct ddpehdr))) == NULL)) {
	    ddpstat.ddps_tooshort++;
	    return;
	}

	deh = mtod(m, struct ddpehdr *);
	bcopy((caddr_t)deh, (caddr_t)&ddpe, sizeof(struct ddpehdr));
	ddpe.deh_bytes = ntohl(ddpe.deh_bytes);
	dlen = ddpe.deh_len;

	if ((cksum = ddpe.deh_sum) == 0) {
	    ddpstat.ddps_nosum++;
	}

	from.sat_addr.s_net = ddpe.deh_snet;
	from.sat_addr.s_node = ddpe.deh_snode;
	from.sat_port = ddpe.deh_sport;
	to.sat_addr.s_net = ddpe.deh_dnet;
	to.sat_addr.s_node = ddpe.deh_dnode;
	to.sat_port = ddpe.deh_dport;

	if (to.sat_addr.s_net == ATADDR_ANYNET) {
	    /*
	     * The TO address doesn't specify a net,
	     * So by definition it's for this net.
	     * Try find ifaddr info with the right phase,
	     * the right interface, and either to our node, a broadcast,
	     * or looped back (though that SHOULD be covered in the other
	     * cases).
	     *
	     * XXX If we have multiple interfaces, then the first with
	     * this node number will match (which may NOT be what we want,
	     * but it's probably safe in 99.999% of cases.
	     */
	    for (aa = at_ifaddr_list; aa != NULL; aa = aa->aa_next) {
		if (phase == 1 && (aa->aa_flags & AFA_PHASE2)) {
		    continue;
		}
		if (phase == 2 && (aa->aa_flags & AFA_PHASE2) == 0) {
		    continue;
		}
		if ((aa->aa_ifp == ifp)
		&& ((to.sat_addr.s_node == AA_SAT(aa)->sat_addr.s_node)
		  || (to.sat_addr.s_node == ATADDR_BCAST)
		  || (ifp->if_flags & IFF_LOOPBACK))) {
		    break;
		}
	    }
	} else {
	    /*
	     * A destination network was given. We just try to find
	     * which ifaddr info matches it.
	     */
	    for (aa = at_ifaddr_list; aa != NULL; aa = aa->aa_next) {
		/*
		 * This is a kludge. Accept packets that are
		 * for any router on a local netrange.
		 */
		if (to.sat_addr.s_net == aa->aa_firstnet &&
			to.sat_addr.s_node == 0) {
		    break;
		}
		/*
		 * Don't use ifaddr info for which we are totally outside the
		 * netrange, and it's not a startup packet.
		 * Startup packets are always implicitly allowed on to
		 * the next test.
		 */
		if (((ntohs(to.sat_addr.s_net) < ntohs(aa->aa_firstnet))
		    || (ntohs(to.sat_addr.s_net) > ntohs(aa->aa_lastnet)))
		 && ((ntohs(to.sat_addr.s_net) < 0xff00)
		    || (ntohs(to.sat_addr.s_net) > 0xfffe))) {
		    continue;
		}

		/*
		 * Don't record a match either if we just don't have a match
		 * in the node address. This can have if the interface
		 * is in promiscuous mode for example.
		 */
		if ((to.sat_addr.s_node != AA_SAT(aa)->sat_addr.s_node)
		&& (to.sat_addr.s_node != ATADDR_BCAST)) {
		    continue;
		}
		break;
	    }
	}
    }

    /*
     * Adjust the length, removing any padding that may have been added
     * at a link layer.  We do this before we attempt to forward a packet,
     * possibly on a different media.
     */
    mlen = m->m_pkthdr.len;
    if (mlen < dlen) {
	ddpstat.ddps_toosmall++;
	m_freem(m);
	return;
    }
    if (mlen > dlen) {
	m_adj(m, dlen - mlen);
    }

    /*
     * If it aint for a net on any of our interfaces,
     * or it IS for a net on a different interface than it came in on,
     * (and it is not looped back) then consider if we should forward it.
     * As we are not really a router this is a bit cheeky, but it may be
     * useful some day.
     */
    if ((aa == NULL)
    || ((to.sat_addr.s_node == ATADDR_BCAST)
      && (aa->aa_ifp != ifp)
      && ((ifp->if_flags & IFF_LOOPBACK) == 0))) {
	/*
	 * If we've explicitly disabled it, don't route anything
	 */
	if (ddp_forward == 0) {
	    m_freem(m);
	    return;
	}
	/*
	 * If the cached forwarding route is still valid, use it.
	 */
	if (forwro.ro_rt
	&& (satosat(&forwro.ro_dst)->sat_addr.s_net != to.sat_addr.s_net
	  || satosat(&forwro.ro_dst)->sat_addr.s_node != to.sat_addr.s_node)) {
	    RTFREE(forwro.ro_rt);
	    forwro.ro_rt = NULL;
	}

	/*
	 * If we don't have a cached one (any more) or it's useless,
	 * Then get a new route.
	 * XXX this could cause a 'route leak'. check this!
	 */
	if (forwro.ro_rt == NULL || forwro.ro_rt->rt_ifp == NULL) {
	    forwro.ro_dst.sa_len = sizeof(struct sockaddr_at);
	    forwro.ro_dst.sa_family = AF_APPLETALK;
	    satosat(&forwro.ro_dst)->sat_addr.s_net = to.sat_addr.s_net;
	    satosat(&forwro.ro_dst)->sat_addr.s_node = to.sat_addr.s_node;
	    rtalloc(&forwro);
	}

	/*
	 * If it's not going to get there on this hop, and it's
	 * already done too many hops, then throw it away.
	 */
	if ((to.sat_addr.s_net != satosat(&forwro.ro_dst)->sat_addr.s_net)
	&& (ddpe.deh_hops == DDP_MAXHOPS)) {
	    m_freem(m);
	    return;
	}

	/*
	 * A ddp router might use the same interface
	 * to forward the packet, which this would not effect.
	 * Don't allow packets to cross from one interface to another however.
	 */
	if (ddp_firewall
	&& ((forwro.ro_rt == NULL)
	  || (forwro.ro_rt->rt_ifp != ifp))) {
	    m_freem(m);
	    return;
	}

	/*
	 * Adjust the header.
	 * If it was a short header then it would have not gotten here,
	 * so we can assume there is room to drop the header in.
	 * XXX what about promiscuous mode, etc...
	 */
	ddpe.deh_hops++;
	ddpe.deh_bytes = htonl(ddpe.deh_bytes);
	bcopy((caddr_t)&ddpe, (caddr_t)deh, sizeof(u_short)); /* XXX deh? */
	if (ddp_route(m, &forwro)) {
	    ddpstat.ddps_cantforward++;
	} else {
	    ddpstat.ddps_forward++;
	}
	return;
    }

    /*
     * It was for us, and we have an ifaddr to use with it.
     */
    from.sat_len = sizeof(struct sockaddr_at);
    from.sat_family = AF_APPLETALK;

    /*
     * We are no longer interested in the link layer.
     * so cut it off.
     */
    if (elh != NULL) {
	m_adj(m, sizeof(struct ddpshdr));
    } else {
	if (ddp_cksum && cksum && cksum != at_cksum(m, sizeof(int))) {
	    ddpstat.ddps_badsum++;
	    m_freem(m);
	    return;
	}
	m_adj(m, sizeof(struct ddpehdr));
    }

    /*
     * Search for ddp protocol control blocks that match these
     * addresses.
     */
    DDP_LIST_SLOCK();
    if ((ddp = ddp_search(&from, &to, aa)) == NULL) {
	goto out;
    }

#ifdef MAC
    SOCK_LOCK(ddp->ddp_socket);
    if (mac_check_socket_deliver(ddp->ddp_socket, m) != 0) {
	SOCK_UNLOCK(ddp->ddp_socket);
	goto out;
    }
    SOCK_UNLOCK(ddp->ddp_socket);
#endif

    /*
     * If we found one, deliver the packet to the socket
     */
    SOCKBUF_LOCK(&ddp->ddp_socket->so_rcv);
    if (sbappendaddr_locked(&ddp->ddp_socket->so_rcv, (struct sockaddr *)&from,
	    m, NULL) == 0) {
    	SOCKBUF_UNLOCK(&ddp->ddp_socket->so_rcv);
	/*
	 * If the socket is full (or similar error) dump the packet.
	 */
	ddpstat.ddps_nosockspace++;
	goto out;
    }
    /*
     * And wake up whatever might be waiting for it
     */
    sorwakeup_locked(ddp->ddp_socket);
    m = NULL;
out:
    DDP_LIST_SUNLOCK();
    if (m != NULL)
	m_freem(m);
}

#if 0
/* As if we haven't got enough of this sort of think floating
around the kernel :) */

#define BPXLEN	48
#define BPALEN	16
#include <ctype.h>
char	hexdig[] = "0123456789ABCDEF";

static void
bprint(char *data, int len)
{
    char	xout[ BPXLEN ], aout[ BPALEN ];
    int		i = 0;

    bzero(xout, BPXLEN);
    bzero(aout, BPALEN);

    for (;;) {
	if (len < 1) {
	    if (i != 0) {
		printf("%s\t%s\n", xout, aout);
	    }
	    printf("%s\n", "(end)");
	    break;
	}

	xout[ (i*3) ] = hexdig[ (*data & 0xf0) >> 4 ];
	xout[ (i*3) + 1 ] = hexdig[ *data & 0x0f ];

	if ((u_char)*data < 0x7f && (u_char)*data > 0x20) {
	    aout[ i ] = *data;
	} else {
	    aout[ i ] = '.';
	}

	xout[ (i*3) + 2 ] = ' ';

	i++;
	len--;
	data++;

	if (i > BPALEN - 2) {
	    printf("%s\t%s\n", xout, aout);
	    bzero(xout, BPXLEN);
	    bzero(aout, BPALEN);
	    i = 0;
	    continue;
	}
    }
}

static void
m_printm(struct mbuf *m)
{
    for (; m; m = m->m_next) {
	bprint(mtod(m, char *), m->m_len);
    }
}
#endif