usr.sbin/IPXrouted/input.c

   1 /*
   2  * Copyright (c) 1985, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Copyright (c) 1995 John Hay.  All rights reserved.
   6  *
   7  * This file includes significant work done at Cornell University by
   8  * Bill Nesheim.  That work included by permission.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  * $FreeBSD: src/usr.sbin/IPXrouted/input.c,v 1.7 1999/08/28 01:15:02 peter Exp $
  39  * $DragonFly: src/usr.sbin/IPXrouted/input.c,v 1.3 2004/03/11 09:38:59 hmp Exp $
  40  *
  41  * @(#)input.c  8.1 (Berkeley) 6/5/93
  42  */
  43
  44 /*
  45  * IPX Routing Table Management Daemon
  46  */
  47 #include "defs.h"
  48
  49 struct sockaddr *
  50 ipx_nettosa(union ipx_net net)
  51 {
  52         static struct sockaddr_ipx sxn;
  53
  54         bzero(&sxn, sizeof (struct sockaddr_ipx));
  55         sxn.sipx_family = AF_IPX;
  56         sxn.sipx_len = sizeof (sxn);
  57         sxn.sipx_addr.x_net = net;
  58         return( (struct sockaddr *)&sxn);
  59
  60 }
  61
  62 /*
  63  * Process a newly received packet.
  64  */
  65 void
  66 rip_input(struct sockaddr *from, int size)
  67 {
  68         int newsize;
  69         int rtchanged = 0;
  70         struct rt_entry *rt;
  71         struct netinfo *n;
  72         struct interface *ifp = 0;
  73         struct afswitch *afp;
  74         struct sockaddr_ipx *ipxp;
  75
  76         ifp = if_ifwithnet(from);
  77         ipxp = (struct sockaddr_ipx *)from;
  78         if (ifp == 0) {
  79                 if(ftrace) {
  80                         fprintf(ftrace, "Received bogus packet from %s\n",
  81                                 ipxdp_ntoa(&ipxp->sipx_addr));
  82                 }
  83                 return;
  84         }
  85
  86         TRACE_INPUT(ifp, from, size);
  87         if (from->sa_family >= AF_MAX)
  88                 return;
  89         afp = &afswitch[from->sa_family];
  90
  91         size -= sizeof (u_short)        /* command */;
  92         n = msg->rip_nets;
  93
  94         switch (ntohs(msg->rip_cmd)) {
  95
  96         case RIPCMD_REQUEST:
  97                 if (ipx_hosteq(satoipx_addr(ifp->int_addr), ipxp->sipx_addr))
  98                         return;
  99                 newsize = 0;
 100                 while (size > 0) {
 101                         if (size < sizeof (struct netinfo))
 102                                 break;
 103                         size -= sizeof (struct netinfo);
 104
 105                         /*
 106                          * A single entry with rip_dst == DSTNETS_ALL and
 107                          * metric ``infinity'' means ``all routes''.
 108                          *
 109                          * XXX According to the IPX RIP spec the metric
 110                          * and tick fields can be anything. So maybe we
 111                          * should not check the metric???
 112                          */
 113                         if (ipx_neteqnn(n->rip_dst, ipx_anynet) &&
 114                             ntohs(n->rip_metric) == HOPCNT_INFINITY &&
 115                             size == 0) {
 116                                 supply(from, 0, ifp, 0);
 117                                 return;
 118                         }
 119                         /*
 120                          * request for specific nets
 121                          */
 122                         rt = rtlookup(ipx_nettosa(n->rip_dst));
 123                         if (ftrace) {
 124                                 fprintf(ftrace,
 125                                         "specific request for %s",
 126                                         ipxdp_nettoa(n->rip_dst));
 127                                 fprintf(ftrace,
 128                                         " yields route %x\n",
 129                                         (u_int)rt);
 130                         }
 131                         /*
 132                          * XXX We break out on the first net that isn't
 133                          * found. The specs is a bit vague here. I'm not
 134                          * sure what we should do.
 135                          */
 136                         if (rt == 0)
 137                                 return;
 138                         /* XXX
 139                          * According to the spec we should not include
 140                          * information about networks for which the number
 141                          * of hops is 16.
 142                          */
 143                         if (rt->rt_metric == (HOPCNT_INFINITY-1))
 144                                 return;
 145                         n->rip_metric = htons( rt == 0 ? HOPCNT_INFINITY :
 146                                 min(rt->rt_metric+1, HOPCNT_INFINITY));
 147                         n->rip_ticks = htons(rt->rt_ticks+1);
 148
 149                         /*
 150                          * We use split horizon with a twist. If the requested
 151                          * net is the directly connected net we supply an
 152                          * answer. This is so that the host can learn about
 153                          * the routers on its net.
 154                          */
 155                         {
 156                                 struct rt_entry *trt = rt;
 157
 158                                 while (trt) {
 159                                         if ((trt->rt_ifp == ifp) &&
 160                                             !ipx_neteqnn(n->rip_dst,
 161                                                 satoipx_addr(ifp->int_addr).x_net))
 162                                                 return;
 163                                         trt = trt->rt_clone;
 164                                 }
 165                                 n++;
 166                                 newsize += sizeof (struct netinfo);
 167                         }
 168                 }
 169                 if (newsize > 0) {
 170                         msg->rip_cmd = htons(RIPCMD_RESPONSE);
 171                         newsize += sizeof (u_short);
 172                         /* should check for if with dstaddr(from) first */
 173                         (*afp->af_output)(ripsock, 0, from, newsize);
 174                         TRACE_OUTPUT(ifp, from, newsize);
 175                         if (ftrace) {
 176                                 /* XXX This should not happen anymore. */
 177                                 if(ifp == 0)
 178                                         fprintf(ftrace, "--- ifp = 0\n");
 179                                 else
 180                                         fprintf(ftrace,
 181                                                 "request arrived on interface %s\n",
 182                                                 ifp->int_name);
 183                         }
 184                 }
 185                 return;
 186
 187         case RIPCMD_RESPONSE:
 188                 /* verify message came from a router */
 189                 if ((*afp->af_portmatch)(from) == 0)
 190                         return;
 191                 (*afp->af_canon)(from);
 192                 /* are we talking to ourselves? */
 193                 if ((ifp = if_ifwithaddr(from)) != 0) {
 194                         rt = rtfind(from);
 195                         if (rt == 0 || (rt->rt_state & RTS_INTERFACE) == 0) {
 196                                 addrouteforif(ifp);
 197                                 rtchanged = 1;
 198                         } else
 199                                 rt->rt_timer = 0;
 200                         return;
 201                 }
 202                 /* Update timer for interface on which the packet arrived.
 203                  * If from other end of a point-to-point link that isn't
 204                  * in the routing tables, (re-)add the route.
 205                  */
 206                 if ((rt = rtfind(from)) && (rt->rt_state & RTS_INTERFACE)) {
 207                         if(ftrace) fprintf(ftrace, "Got route\n");
 208                         rt->rt_timer = 0;
 209                 } else if ((ifp = if_ifwithdstaddr(from)) != 0) {
 210                         if(ftrace) fprintf(ftrace, "Got partner\n");
 211                         addrouteforif(ifp);
 212                         rtchanged = 1;
 213                 }
 214                 for (; size > 0; size -= sizeof (struct netinfo), n++) {
 215                         struct sockaddr *sa;
 216                         if (size < sizeof (struct netinfo))
 217                                 break;
 218                         if ((unsigned) ntohs(n->rip_metric) > HOPCNT_INFINITY)
 219                                 continue;
 220                         rt = rtfind(sa = ipx_nettosa(n->rip_dst));
 221                         if (rt == 0) {
 222                                 if (ntohs(n->rip_metric) == HOPCNT_INFINITY)
 223                                         continue;
 224                                 rtadd(sa, from, ntohs(n->rip_metric),
 225                                         ntohs(n->rip_ticks), 0);
 226                                 rtchanged = 1;
 227                                 continue;
 228                         }
 229
 230                         /*
 231                          * A clone is a different route to the same net
 232                          * with exactly the same cost (ticks and metric).
 233                          * They must all be recorded because those interfaces
 234                          * must be handled in the same way as the first route
 235                          * to that net. ie When using the split horizon
 236                          * algorithm we must look at these interfaces also.
 237                          *
 238                          * Update if from gateway and different,
 239                          * from anywhere and less ticks or
 240                          * if same ticks and shorter,
 241                          * or getting stale and equivalent.
 242                          */
 243                         if (!equal(from, &rt->rt_router) &&
 244                             ntohs(n->rip_ticks) == rt->rt_ticks &&
 245                             ntohs(n->rip_metric) == rt->rt_metric &&
 246                             ntohs(n->rip_metric) != HOPCNT_INFINITY) {
 247                                 struct rt_entry *trt = rt->rt_clone;
 248
 249                                 while (trt) {
 250                                         if (equal(from, &trt->rt_router)) {
 251                                                 trt->rt_timer = 0;
 252                                                 break;
 253                                         }
 254                                         trt = trt->rt_clone;
 255                                 }
 256                                 if (trt == NULL) {
 257                                         rtadd_clone(rt, sa, from,
 258                                                     ntohs(n->rip_metric),
 259                                                     ntohs(n->rip_ticks), 0);
 260                                 }
 261                                 continue;
 262                         }
 263                         if ((equal(from, &rt->rt_router) &&
 264                             ((ntohs(n->rip_ticks) != rt->rt_ticks) ||
 265                             (ntohs(n->rip_metric) != rt->rt_metric))) ||
 266                             (ntohs(n->rip_ticks) < rt->rt_ticks) ||
 267                             ((ntohs(n->rip_ticks) == rt->rt_ticks) &&
 268                             (ntohs(n->rip_metric) < rt->rt_metric)) ||
 269                             (rt->rt_timer > (EXPIRE_TIME*2/3) &&
 270                             rt->rt_metric == ntohs(n->rip_metric) &&
 271                             ntohs(n->rip_metric) != HOPCNT_INFINITY)) {
 272                                 rtchange(rt, from, ntohs(n->rip_metric),
 273                                         ntohs(n->rip_ticks));
 274                                 if (ntohs(n->rip_metric) == HOPCNT_INFINITY)
 275                                         rt->rt_timer = EXPIRE_TIME;
 276                                 else
 277                                         rt->rt_timer = 0;
 278                                 rtchanged = 1;
 279                         } else if (equal(from, &rt->rt_router) &&
 280                                    (ntohs(n->rip_ticks) == rt->rt_ticks) &&
 281                                    (ntohs(n->rip_metric) == rt->rt_metric) &&
 282                                    (ntohs(n->rip_metric) != HOPCNT_INFINITY)) {
 283                                 rt->rt_timer = 0;
 284                         }
 285                 }
 286                 if (rtchanged) {
 287                         struct rthash *rh;
 288                         struct rt_entry *rt;
 289
 290                         toall(supply, NULL, 1);
 291                         for (rh = nethash; rh < &nethash[ROUTEHASHSIZ]; rh++)
 292                                 for (rt = rh->rt_forw;
 293                                     rt != (struct rt_entry *)rh;
 294                                     rt = rt->rt_forw)
 295                                         rt->rt_state &= ~RTS_CHANGED;
 296                 }
 297
 298                 return;
 299         }
 300 }