sys/netproto/atalk/ddp_output.c

   1 /*
   2  * Copyright (c) 1990,1991 Regents of The University of Michigan.
   3  * All Rights Reserved.
   4  *
   5  * Permission to use, copy, modify, and distribute this software and
   6  * its documentation for any purpose and without fee is hereby granted,
   7  * provided that the above copyright notice appears in all copies and
   8  * that both that copyright notice and this permission notice appear
   9  * in supporting documentation, and that the name of The University
  10  * of Michigan not be used in advertising or publicity pertaining to
  11  * distribution of the software without specific, written prior
  12  * permission. This software is supplied as is without expressed or
  13  * implied warranties of any kind.
  14  *
  15  *      Research Systems Unix Group
  16  *      The University of Michigan
  17  *      c/o Mike Clark
  18  *      535 W. William Street
  19  *      Ann Arbor, Michigan
  20  *      +1-313-763-0525
  21  *      netatalk@itd.umich.edu
  22  */
  23
  24 /* $FreeBSD: src/sys/netatalk/ddp_output.c,v 1.13.6.1 2000/06/02 22:39:07 archie Exp $ */
  25 /* $DragonFly: src/sys/netproto/atalk/ddp_output.c,v 1.9 2006/12/22 23:57:53 swildner Exp $ */
  26
  27 #include <sys/param.h>
  28 #include <sys/systm.h>
  29 #include <sys/mbuf.h>
  30 #include <sys/socket.h>
  31 #include <sys/socketvar.h>
  32
  33 #include <net/if.h>
  34 #include <net/route.h>
  35
  36 #undef s_net
  37
  38 #include "at.h"
  39 #include "at_var.h"
  40 #include "ddp.h"
  41 #include "ddp_var.h"
  42 #include "at_extern.h"
  43
  44 int     ddp_cksum = 1;
  45
  46 int
  47 ddp_output(struct mbuf *m, struct socket *so, ...)
  48 {
  49     struct ddpehdr      *deh;
  50     struct ddpcb *ddp = sotoddpcb( so );
  51
  52     M_PREPEND( m, sizeof( struct ddpehdr ), MB_WAIT );
  53     if (m == NULL)
  54             return (ENOBUFS);
  55
  56     deh = mtod( m, struct ddpehdr *);
  57     deh->deh_pad = 0;
  58     deh->deh_hops = 0;
  59
  60     deh->deh_len = m->m_pkthdr.len;
  61
  62     deh->deh_dnet = ddp->ddp_fsat.sat_addr.s_net;
  63     deh->deh_dnode = ddp->ddp_fsat.sat_addr.s_node;
  64     deh->deh_dport = ddp->ddp_fsat.sat_port;
  65     deh->deh_snet = ddp->ddp_lsat.sat_addr.s_net;
  66     deh->deh_snode = ddp->ddp_lsat.sat_addr.s_node;
  67     deh->deh_sport = ddp->ddp_lsat.sat_port;
  68
  69     /*
  70      * The checksum calculation is done after all of the other bytes have
  71      * been filled in.
  72      */
  73     if ( ddp_cksum ) {
  74         deh->deh_sum = at_cksum( m, sizeof( int ));
  75     } else {
  76         deh->deh_sum = 0;
  77     }
  78     deh->deh_bytes = htonl( deh->deh_bytes );
  79
  80 #ifdef NETATALK_DEBUG
  81     kprintf ("ddp_output: from %d.%d:%d to %d.%d:%d\n",
  82         ntohs(deh->deh_snet), deh->deh_snode, deh->deh_sport,
  83         ntohs(deh->deh_dnet), deh->deh_dnode, deh->deh_dport);
  84 #endif
  85     return( ddp_route( m, &ddp->ddp_route ));
  86 }
  87
  88 u_short
  89 at_cksum( struct mbuf *m, int skip)
  90 {
  91     u_char      *data, *end;
  92     u_long      cksum = 0;
  93
  94     for (; m; m = m->m_next ) {
  95         for ( data = mtod( m, u_char * ), end = data + m->m_len; data < end;
  96                 data++ ) {
  97             if ( skip ) {
  98                 skip--;
  99                 continue;
 100             }
 101             cksum = ( cksum + *data ) << 1;
 102             if ( cksum & 0x00010000 ) {
 103                 cksum++;
 104             }
 105             cksum &= 0x0000ffff;
 106         }
 107     }
 108
 109     if ( cksum == 0 ) {
 110         cksum = 0x0000ffff;
 111     }
 112     return( (u_short)cksum );
 113 }
 114
 115 int
 116 ddp_route( struct mbuf *m, struct route *ro)
 117 {
 118     struct sockaddr_at  gate;
 119     struct elaphdr      *elh;
 120     struct mbuf         *m0;
 121     struct at_ifaddr    *aa = NULL;
 122     struct ifnet        *ifp = NULL;
 123     u_short             net;
 124     int error;
 125
 126 #if 0
 127     /* Check for net zero, node zero ("myself") */
 128     if (satosat(&ro->ro_dst)->sat_addr.s_net == ATADDR_ANYNET
 129         && satosat(&ro->ro_dst)->sat_addr.s_node == ATADDR_ANYNODE) {
 130             /* Find the loopback interface */
 131     }
 132 #endif
 133
 134     /*
 135      * if we have a route, find the ifa that refers to this route.
 136      * I.e The ifa used to get to the gateway.
 137      */
 138     if ( (ro->ro_rt == NULL)
 139     || ( ro->ro_rt->rt_ifa == NULL )
 140     || ( (ifp = ro->ro_rt->rt_ifa->ifa_ifp) == NULL )) {
 141         rtalloc(ro);
 142     }
 143     if ( (ro->ro_rt != NULL)
 144     && ( ro->ro_rt->rt_ifa )
 145     && ( ifp = ro->ro_rt->rt_ifa->ifa_ifp )) {
 146         net = ntohs(satosat(ro->ro_rt->rt_gateway)->sat_addr.s_net);
 147         for ( aa = at_ifaddr; aa; aa = aa->aa_next ) {
 148             if (((net == 0) || (aa->aa_ifp == ifp)) &&
 149                     net >= ntohs( aa->aa_firstnet ) &&
 150                     net <= ntohs( aa->aa_lastnet )) {
 151                 break;
 152             }
 153         }
 154     } else {
 155         m_freem( m );
 156 #ifdef NETATALK_DEBUG
 157         if (ro->ro_rt == NULL)
 158             kprintf ("ddp_route: no ro_rt.\n");
 159         else if (ro->ro_rt->rt_ifa == NULL)
 160             kprintf ("ddp_route: no ro_rt->rt_ifa\n");
 161         else
 162             kprintf ("ddp_route: no ro_rt->rt_ifa->ifa_ifp\n");
 163 #endif
 164         return( ENETUNREACH );
 165     }
 166
 167     if ( aa == NULL ) {
 168 #ifdef NETATALK_DEBUG
 169         kprintf( "ddp_route: no atalk address found for %s\n",
 170             ifp->if_xname);
 171 #endif
 172         m_freem( m );
 173         return( ENETUNREACH );
 174     }
 175
 176     /*
 177      * if the destination address is on a directly attached node use that,
 178      * else use the official gateway.
 179      */
 180     if ( ntohs( satosat( &ro->ro_dst )->sat_addr.s_net ) >=
 181             ntohs( aa->aa_firstnet ) &&
 182             ntohs( satosat( &ro->ro_dst )->sat_addr.s_net ) <=
 183             ntohs( aa->aa_lastnet )) {
 184         gate = *satosat( &ro->ro_dst );
 185     } else {
 186         gate = *satosat( ro->ro_rt->rt_gateway );
 187     }
 188
 189     /*
 190      * There are several places in the kernel where data is added to
 191      * an mbuf without ensuring that the mbuf pointer is aligned.
 192      * This is bad for transition routing, since phase 1 and phase 2
 193      * packets end up poorly aligned due to the three byte elap header.
 194      */
 195     if ( !(aa->aa_flags & AFA_PHASE2) ) {
 196         MGET( m0, MB_WAIT, MT_HEADER );
 197         if ( m0 == 0 ) {
 198             m_freem( m );
 199             kprintf("ddp_route: no buffers\n");
 200             return( ENOBUFS );
 201         }
 202         m0->m_next = m;
 203         /* XXX perhaps we ought to align the header? */
 204         m0->m_len = SZ_ELAPHDR;
 205         m = m0;
 206
 207         elh = mtod( m, struct elaphdr *);
 208         elh->el_snode = satosat( &aa->aa_addr )->sat_addr.s_node;
 209         elh->el_type = ELAP_DDPEXTEND;
 210         elh->el_dnode = gate.sat_addr.s_node;
 211     }
 212     ro->ro_rt->rt_use++;
 213
 214 #ifdef NETATALK_DEBUG
 215     kprintf ("ddp_route: from %d.%d to %d.%d, via %d.%d (%s)\n",
 216         ntohs(satosat(&aa->aa_addr)->sat_addr.s_net),
 217         satosat(&aa->aa_addr)->sat_addr.s_node,
 218         ntohs(satosat(&ro->ro_dst)->sat_addr.s_net),
 219         satosat(&ro->ro_dst)->sat_addr.s_node,
 220         ntohs(gate.sat_addr.s_net),
 221         gate.sat_addr.s_node,
 222         ifp->if_xname);
 223 #endif
 224
 225     /* short-circuit the output if we're sending this to ourself */
 226     if ((satosat(&aa->aa_addr)->sat_addr.s_net  == satosat(&ro->ro_dst)->sat_addr.s_net) &&
 227         (satosat(&aa->aa_addr)->sat_addr.s_node == satosat(&ro->ro_dst)->sat_addr.s_node))
 228     {
 229         return (if_simloop(ifp, m, gate.sat_family, 0));
 230     }
 231
 232     /* XXX */
 233     lwkt_serialize_enter(ifp->if_serializer);
 234     error = (*ifp->if_output)( ifp, m, (struct sockaddr *)&gate, NULL);
 235     lwkt_serialize_exit(ifp->if_serializer);
 236     return (error);
 237 }