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

     /*
      * Copyright (c) 1990,1994 Regents of The University of Michigan.
      * All Rights Reserved.  See COPYRIGHT.
      *
      * $FreeBSD: releng/5.2/sys/netatalk/ddp_input.c 122320 2003-11-08 22:28:40Z sam $
      */
     
     #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/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)
    {
            GIANT_REQUIRED;
    
            /*
             * 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)) == 0)) {
                    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);
    
            GIANT_REQUIRED;
    
            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 ) {
            /*
            * 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 ))) == 0 )) {
               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; aa; 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 ))) == 0 )) {
               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; aa; 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; aa; 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 = (struct rtentry *)0;
           }
   
           /*
            * 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 == (struct rtentry *)0
           || forwro.ro_rt->rt_ifp == (struct ifnet *)0 ) {
               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 ) {
           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. 
        */
       if (( ddp = ddp_search( &from, &to, aa )) == NULL ) {
           m_freem( m );
           return;
       }
   
   #ifdef MAC
       if (mac_check_socket_deliver(ddp->ddp_socket, m) != 0) {
           m_freem( m );
           return;
       }
   #endif
   
       /* 
        * If we found one, deliver th epacket to the socket
        */
       if ( sbappendaddr( &ddp->ddp_socket->so_rcv, (struct sockaddr *)&from,
               m, (struct mbuf *)0 ) == 0 ) {
           /* 
            * If the socket is full (or similar error) dump the packet.
            */
           ddpstat.ddps_nosockspace++;
           m_freem( m );
           return;
       }
       /*
        * And wake up whatever might be waiting for it
        */
       sorwakeup( ddp->ddp_socket );
   }
   
   #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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