FreeBSD/Linux Kernel Cross Reference
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
     *
     * $FreeBSD$
     */
    
    #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

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