The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/netatalk/ddp_input.c

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    1 /*
    2  * Copyright (c) 1990,1994 Regents of The University of Michigan.
    3  * All Rights Reserved.  See COPYRIGHT.
    4  */
    5 
    6 #include <sys/param.h>
    7 #include <sys/systm.h>
    8 #include <sys/kernel.h>
    9 #include <net/netisr.h>
   10 #include <sys/mbuf.h>
   11 #include <sys/socket.h>
   12 #include <sys/socketvar.h>
   13 #include <net/if.h>
   14 #include <net/route.h>
   15 
   16 #include <netatalk/at.h>
   17 #include <netatalk/at_var.h>
   18 #include <netatalk/ddp.h>
   19 #include <netatalk/ddp_var.h>
   20 #include <netatalk/at_extern.h>
   21 
   22 struct ifqueue          atintrq1, atintrq2;
   23 
   24 static volatile int     ddp_forward = 1;
   25 static volatile int     ddp_firewall = 0;
   26 static struct ddpstat   ddpstat;
   27 static struct route     forwro;
   28 
   29 static void     ddp_input(struct mbuf *, struct ifnet *, struct elaphdr *, int);
   30 
   31 /*
   32  * Could probably merge these two code segments a little better...
   33  */
   34 static void
   35 atintr( void )
   36 {
   37     struct elaphdr      *elhp, elh;
   38     struct ifnet        *ifp;
   39     struct mbuf         *m;
   40     int                 s;
   41 
   42     /*
   43      * First pull off all the phase 2 packets.
   44      */
   45     for (;;) {
   46         s = splimp();
   47 
   48         IF_DEQUEUE( &atintrq2, m );
   49 
   50         splx( s );
   51 
   52         if ( m == 0 ) {                 /* no more queued packets */
   53             break;
   54         }
   55 
   56         ifp = m->m_pkthdr.rcvif;
   57         ddp_input( m, ifp, (struct elaphdr *)NULL, 2 );
   58     }
   59 
   60     /*
   61      * Then pull off all the phase 1 packets.
   62      */
   63     for (;;) {
   64         s = splimp();
   65 
   66         IF_DEQUEUE( &atintrq1, m );
   67 
   68         splx( s );
   69 
   70         if ( m == 0 ) {                 /* no more queued packets */
   71             break;
   72         }
   73 
   74         ifp = m->m_pkthdr.rcvif;
   75 
   76         if ( m->m_len < SZ_ELAPHDR &&
   77                 (( m = m_pullup( m, SZ_ELAPHDR )) == 0 )) {
   78             ddpstat.ddps_tooshort++;
   79             continue;
   80         }
   81 
   82         /*
   83          * this seems a little dubios, but I don't know phase 1 so leave it.
   84          */
   85         elhp = mtod( m, struct elaphdr *);
   86         m_adj( m, SZ_ELAPHDR );
   87 
   88         if ( elhp->el_type == ELAP_DDPEXTEND ) {
   89             ddp_input( m, ifp, (struct elaphdr *)NULL, 1 );
   90         } else {
   91             bcopy((caddr_t)elhp, (caddr_t)&elh, SZ_ELAPHDR );
   92             ddp_input( m, ifp, &elh, 1 );
   93         }
   94     }
   95     return;
   96 }
   97 
   98 NETISR_SET(NETISR_ATALK, atintr);
   99 
  100 static void
  101 ddp_input( m, ifp, elh, phase )
  102     struct mbuf         *m;
  103     struct ifnet        *ifp;
  104     struct elaphdr      *elh;
  105     int                 phase;
  106 {
  107     struct sockaddr_at  from, to;
  108     struct ddpshdr      *dsh, ddps;
  109     struct at_ifaddr    *aa;
  110     struct ddpehdr      *deh = NULL, ddpe;
  111     struct ddpcb        *ddp;
  112     int                 dlen, mlen;
  113     u_short             cksum = 0;
  114 
  115     bzero( (caddr_t)&from, sizeof( struct sockaddr_at ));
  116     bzero( (caddr_t)&to, sizeof( struct sockaddr_at ));
  117     if ( elh ) {
  118         /*
  119          * Extract the information in the short header.
  120          * netowrk information is defaulted to ATADDR_ANYNET
  121          * and node information comes from the elh info.
  122          * We must be phase 1.
  123          */
  124         ddpstat.ddps_short++;
  125 
  126         if ( m->m_len < sizeof( struct ddpshdr ) &&
  127                 (( m = m_pullup( m, sizeof( struct ddpshdr ))) == 0 )) {
  128             ddpstat.ddps_tooshort++;
  129             return;
  130         }
  131 
  132         dsh = mtod( m, struct ddpshdr *);
  133         bcopy( (caddr_t)dsh, (caddr_t)&ddps, sizeof( struct ddpshdr ));
  134         ddps.dsh_bytes = ntohl( ddps.dsh_bytes );
  135         dlen = ddps.dsh_len;
  136 
  137         to.sat_addr.s_net = ATADDR_ANYNET;
  138         to.sat_addr.s_node = elh->el_dnode;
  139         to.sat_port = ddps.dsh_dport;
  140         from.sat_addr.s_net = ATADDR_ANYNET;
  141         from.sat_addr.s_node = elh->el_snode;
  142         from.sat_port = ddps.dsh_sport;
  143 
  144         /* 
  145          * Make sure that we point to the phase1 ifaddr info 
  146          * and that it's valid for this packet.
  147          */
  148         for ( aa = at_ifaddr; aa; aa = aa->aa_next ) {
  149             if ( (aa->aa_ifp == ifp)
  150             && ( (aa->aa_flags & AFA_PHASE2) == 0)
  151             && ( (to.sat_addr.s_node == AA_SAT( aa )->sat_addr.s_node)
  152               || (to.sat_addr.s_node == ATADDR_BCAST))) {
  153                 break;
  154             }
  155         }
  156         /* 
  157          * maybe we got a broadcast not meant for us.. ditch it.
  158          */
  159         if ( aa == NULL ) {
  160             m_freem( m );
  161             return;
  162         }
  163     } else {
  164         /*
  165          * There was no 'elh' passed on. This could still be
  166          * either phase1 or phase2.
  167          * We have a long header, but we may be running on a phase 1 net.
  168          * Extract out all the info regarding this packet's src & dst.
  169          */
  170         ddpstat.ddps_long++;
  171 
  172         if ( m->m_len < sizeof( struct ddpehdr ) &&
  173                 (( m = m_pullup( m, sizeof( struct ddpehdr ))) == 0 )) {
  174             ddpstat.ddps_tooshort++;
  175             return;
  176         }
  177 
  178         deh = mtod( m, struct ddpehdr *);
  179         bcopy( (caddr_t)deh, (caddr_t)&ddpe, sizeof( struct ddpehdr ));
  180         ddpe.deh_bytes = ntohl( ddpe.deh_bytes );
  181         dlen = ddpe.deh_len;
  182 
  183         if (( cksum = ddpe.deh_sum ) == 0 ) {
  184             ddpstat.ddps_nosum++;
  185         }
  186 
  187         from.sat_addr.s_net = ddpe.deh_snet;
  188         from.sat_addr.s_node = ddpe.deh_snode;
  189         from.sat_port = ddpe.deh_sport;
  190         to.sat_addr.s_net = ddpe.deh_dnet;
  191         to.sat_addr.s_node = ddpe.deh_dnode;
  192         to.sat_port = ddpe.deh_dport;
  193 
  194         if ( to.sat_addr.s_net == ATADDR_ANYNET ) {
  195             /*
  196              * The TO address doesn't specify a net,
  197              * So by definition it's for this net.
  198              * Try find ifaddr info with the right phase, 
  199              * the right interface, and either to our node, a broadcast,
  200              * or looped back (though that SHOULD be covered in the other
  201              * cases).
  202              *
  203              * XXX If we have multiple interfaces, then the first with
  204              * this node number will match (which may NOT be what we want,
  205              * but it's probably safe in 99.999% of cases.
  206              */
  207             for ( aa = at_ifaddr; aa; aa = aa->aa_next ) {
  208                 if ( phase == 1 && ( aa->aa_flags & AFA_PHASE2 )) {
  209                     continue;
  210                 }
  211                 if ( phase == 2 && ( aa->aa_flags & AFA_PHASE2 ) == 0 ) {
  212                     continue;
  213                 }
  214                 if ( (aa->aa_ifp == ifp)
  215                 && ( (to.sat_addr.s_node == AA_SAT( aa )->sat_addr.s_node)
  216                   || (to.sat_addr.s_node == ATADDR_BCAST)
  217                   || (ifp->if_flags & IFF_LOOPBACK))) {
  218                     break;
  219                 }
  220             }
  221         } else {
  222             /* 
  223              * A destination network was given. We just try to find 
  224              * which ifaddr info matches it.
  225              */
  226             for ( aa = at_ifaddr; aa; aa = aa->aa_next ) {
  227                 /*
  228                  * This is a kludge. Accept packets that are
  229                  * for any router on a local netrange.
  230                  */
  231                 if ( to.sat_addr.s_net == aa->aa_firstnet &&
  232                         to.sat_addr.s_node == 0 ) {
  233                     break;
  234                 }
  235                 /*
  236                  * Don't use ifaddr info for which we are totally outside the
  237                  * netrange, and it's not a startup packet.
  238                  * Startup packets are always implicitly allowed on to
  239                  * the next test.
  240                  */
  241                 if ((( ntohs( to.sat_addr.s_net ) < ntohs( aa->aa_firstnet ))
  242                     || (ntohs( to.sat_addr.s_net ) > ntohs( aa->aa_lastnet )))
  243                  && (( ntohs( to.sat_addr.s_net ) < 0xff00)
  244                     || (ntohs( to.sat_addr.s_net ) > 0xfffe ))) {
  245                     continue;
  246                 }
  247 
  248                 /*
  249                  * Don't record a match either if we just don't have a match
  250                  * in the node address. This can have if the interface
  251                  * is in promiscuous mode for example.
  252                  */
  253                 if (( to.sat_addr.s_node != AA_SAT( aa )->sat_addr.s_node)
  254                 && (to.sat_addr.s_node != ATADDR_BCAST) ) {
  255                     continue;
  256                 }
  257                 break;
  258             }
  259         }
  260     }
  261 
  262     /*
  263      * Adjust the length, removing any padding that may have been added
  264      * at a link layer.  We do this before we attempt to forward a packet,
  265      * possibly on a different media.
  266      */
  267     mlen = m->m_pkthdr.len;
  268     if ( mlen < dlen ) {
  269         ddpstat.ddps_toosmall++;
  270         m_freem( m );
  271         return;
  272     }
  273     if ( mlen > dlen ) {
  274         m_adj( m, dlen - mlen );
  275     }
  276 
  277     /*
  278      * If it aint for a net on any of our interfaces,
  279      * or it IS for a net on a different interface than it came in on,
  280      * (and it is not looped back) then consider if we should forward it.
  281      * As we are not really a router this is a bit cheeky, but it may be
  282      * useful some day.
  283      */
  284     if ( (aa == NULL)
  285     || ( (to.sat_addr.s_node == ATADDR_BCAST)
  286       && (aa->aa_ifp != ifp)
  287       && (( ifp->if_flags & IFF_LOOPBACK ) == 0 ))) {
  288         /* 
  289          * If we've explicitly disabled it, don't route anything
  290          */
  291         if ( ddp_forward == 0 ) {
  292             m_freem( m );
  293             return;
  294         }
  295         /* 
  296          * If the cached forwarding route is still valid, use it.
  297          */
  298         if ( forwro.ro_rt
  299         && ( satosat(&forwro.ro_dst)->sat_addr.s_net != to.sat_addr.s_net
  300           || satosat(&forwro.ro_dst)->sat_addr.s_node != to.sat_addr.s_node )) {
  301             RTFREE( forwro.ro_rt );
  302             forwro.ro_rt = (struct rtentry *)0;
  303         }
  304 
  305         /*
  306          * If we don't have a cached one (any more) or it's useless,
  307          * Then get a new route.
  308          * XXX this could cause a 'route leak'. check this!
  309          */
  310         if ( forwro.ro_rt == (struct rtentry *)0
  311         || forwro.ro_rt->rt_ifp == (struct ifnet *)0 ) {
  312             forwro.ro_dst.sa_len = sizeof( struct sockaddr_at );
  313             forwro.ro_dst.sa_family = AF_APPLETALK;
  314             satosat(&forwro.ro_dst)->sat_addr.s_net = to.sat_addr.s_net;
  315             satosat(&forwro.ro_dst)->sat_addr.s_node = to.sat_addr.s_node;
  316             rtalloc(&forwro);
  317         }
  318 
  319         /* 
  320          * If it's not going to get there on this hop, and it's
  321          * already done too many hops, then throw it away.
  322          */
  323         if ( (to.sat_addr.s_net != satosat( &forwro.ro_dst )->sat_addr.s_net)
  324         && (ddpe.deh_hops == DDP_MAXHOPS) ) {
  325             m_freem( m );
  326             return;
  327         }
  328 
  329         /*
  330          * A ddp router might use the same interface
  331          * to forward the packet, which this would not effect.
  332          * Don't allow packets to cross from one interface to another however.
  333          */
  334         if ( ddp_firewall
  335         && ( (forwro.ro_rt == NULL)
  336           || (forwro.ro_rt->rt_ifp != ifp))) {
  337             m_freem( m );
  338             return;
  339         }
  340 
  341         /*
  342          * Adjust the header.
  343          * If it was a short header then it would have not gotten here,
  344          * so we can assume there is room to drop the header in.
  345          * XXX what about promiscuous mode, etc...
  346          */
  347         ddpe.deh_hops++;
  348         ddpe.deh_bytes = htonl( ddpe.deh_bytes );
  349         bcopy( (caddr_t)&ddpe, (caddr_t)deh, sizeof( u_short )); /* XXX deh? */
  350         if ( ddp_route( m, &forwro )) {
  351             ddpstat.ddps_cantforward++;
  352         } else {
  353             ddpstat.ddps_forward++;
  354         }
  355         return;
  356     }
  357 
  358     /*
  359      * It was for us, and we have an ifaddr to use with it.
  360      */
  361     from.sat_len = sizeof( struct sockaddr_at );
  362     from.sat_family = AF_APPLETALK;
  363 
  364     /* 
  365      * We are no longer interested in the link layer.
  366      * so cut it off.
  367      */
  368     if ( elh ) {
  369         m_adj( m, sizeof( struct ddpshdr ));
  370     } else {
  371         if ( ddp_cksum && cksum && cksum != at_cksum( m, sizeof( int ))) {
  372             ddpstat.ddps_badsum++;
  373             m_freem( m );
  374             return;
  375         }
  376         m_adj( m, sizeof( struct ddpehdr ));
  377     }
  378 
  379     /* 
  380      * Search for ddp protocol control blocks that match these
  381      * addresses. 
  382      */
  383     if (( ddp = ddp_search( &from, &to, aa )) == NULL ) {
  384         m_freem( m );
  385         return;
  386     }
  387 
  388     /* 
  389      * If we found one, deliver th epacket to the socket
  390      */
  391     if ( sbappendaddr( &ddp->ddp_socket->so_rcv, (struct sockaddr *)&from,
  392             m, (struct mbuf *)0 ) == 0 ) {
  393         /* 
  394          * If the socket is full (or similar error) dump the packet.
  395          */
  396         ddpstat.ddps_nosockspace++;
  397         m_freem( m );
  398         return;
  399     }
  400     /*
  401      * And wake up whatever might be waiting for it
  402      */
  403     sorwakeup( ddp->ddp_socket );
  404 }
  405 
  406 #if 0
  407 /* As if we haven't got enough of this sort of think floating
  408 around the kernel :) */
  409 
  410 #define BPXLEN  48
  411 #define BPALEN  16
  412 #include <ctype.h>
  413 char    hexdig[] = "0123456789ABCDEF";
  414 
  415 static void
  416 bprint( char *data, int len )
  417 {
  418     char        xout[ BPXLEN ], aout[ BPALEN ];
  419     int         i = 0;
  420 
  421     bzero( xout, BPXLEN );
  422     bzero( aout, BPALEN );
  423 
  424     for ( ;; ) {
  425         if ( len < 1 ) {
  426             if ( i != 0 ) {
  427                 printf( "%s\t%s\n", xout, aout );
  428             }
  429             printf( "%s\n", "(end)" );
  430             break;
  431         }
  432 
  433         xout[ (i*3) ] = hexdig[ ( *data & 0xf0 ) >> 4 ];
  434         xout[ (i*3) + 1 ] = hexdig[ *data & 0x0f ];
  435 
  436         if ( (u_char)*data < 0x7f && (u_char)*data > 0x20 ) {
  437             aout[ i ] = *data;
  438         } else {
  439             aout[ i ] = '.';
  440         }
  441 
  442         xout[ (i*3) + 2 ] = ' ';
  443 
  444         i++;
  445         len--;
  446         data++;
  447 
  448         if ( i > BPALEN - 2 ) {
  449             printf( "%s\t%s\n", xout, aout );
  450             bzero( xout, BPXLEN );
  451             bzero( aout, BPALEN );
  452             i = 0;
  453             continue;
  454         }
  455     }
  456 }
  457 
  458 static void
  459 m_printm( struct mbuf *m )
  460 {
  461     for (; m; m = m->m_next ) {
  462         bprint( mtod( m, char * ), m->m_len );
  463     }
  464 }
  465 #endif

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