net/ax25/ax25_route.c

   1 /*
   2  *      AX.25 release 037
   3  *
   4  *      This code REQUIRES 2.1.15 or higher/ NET3.038
   5  *
   6  *      This module:
   7  *              This module is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              as published by the Free Software Foundation; either version
  10  *              2 of the License, or (at your option) any later version.
  11  *
  12  *      Other kernels modules in this kit are generally BSD derived. See the copyright headers.
  13  *
  14  *
  15  *      History
  16  *      AX.25 020       Jonathan(G4KLX) First go.
  17  *      AX.25 022       Jonathan(G4KLX) Added the actual meat to this - we now have a nice heard list.
  18  *      AX.25 025       Alan(GW4PTS)    First cut at autobinding by route scan.
  19  *      AX.25 028b      Jonathan(G4KLX) Extracted AX25 control block from the
  20  *                                      sock structure. Device removal now
  21  *                                      removes the heard structure.
  22  *      AX.25 029       Steven(GW7RRM)  Added /proc information for uid/callsign mapping.
  23  *                      Jonathan(G4KLX) Handling of IP mode in the routing list and /proc entry.
  24  *      AX.25 030       Jonathan(G4KLX) Added digi-peaters to routing table, and
  25  *                                      ioctls to manipulate them. Added port
  26  *                                      configuration.
  27  *      AX.25 031       Jonathan(G4KLX) Added concept of default route.
  28  *                      Joerg(DL1BKE)   ax25_rt_build_path() find digipeater list and device by
  29  *                                      destination call. Needed for IP routing via digipeater
  30  *                      Jonathan(G4KLX) Added routing for IP datagram packets.
  31  *                      Joerg(DL1BKE)   Changed routing for IP datagram and VC to use a default
  32  *                                      route if available. Does not overwrite default routes
  33  *                                      on route-table overflow anymore.
  34  *                      Joerg(DL1BKE)   Fixed AX.25 routing of IP datagram and VC, new ioctl()
  35  *                                      "SIOCAX25OPTRT" to set IP mode and a 'permanent' flag
  36  *                                      on routes.
  37  *      AX.25 033       Jonathan(G4KLX) Remove auto-router.
  38  *                      Joerg(DL1BKE)   Moved BPQ Ethernet driver to separate device.
  39  *      AX.25 035       Frederic(F1OAT) Support for pseudo-digipeating.
  40  *                      Jonathan(G4KLX) Support for packet forwarding.
  41  *                      Arnaldo C. Melo s/suser/capable/
  42  */
  43
  44 #include <linux/errno.h>
  45 #include <linux/types.h>
  46 #include <linux/socket.h>
  47 #include <linux/in.h>
  48 #include <linux/kernel.h>
  49 #include <linux/sched.h>
  50 #include <linux/timer.h>
  51 #include <linux/string.h>
  52 #include <linux/sockios.h>
  53 #include <linux/net.h>
  54 #include <net/ax25.h>
  55 #include <linux/inet.h>
  56 #include <linux/netdevice.h>
  57 #include <linux/if_arp.h>
  58 #include <linux/skbuff.h>
  59 #include <net/sock.h>
  60 #include <asm/uaccess.h>
  61 #include <asm/system.h>
  62 #include <linux/fcntl.h>
  63 #include <linux/mm.h>
  64 #include <linux/interrupt.h>
  65 #include <linux/init.h>
  66
  67 static ax25_route *ax25_route_list;
  68
  69 static ax25_route *ax25_find_route(ax25_address *, struct net_device *);
  70
  71 /*
  72  * small macro to drop non-digipeated digipeaters and reverse path
  73  */
  74 static inline void ax25_route_invert(ax25_digi *in, ax25_digi *out)
  75 {
  76         int k;
  77
  78         for (k = 0; k < in->ndigi; k++)
  79                 if (!in->repeated[k])
  80                         break;
  81
  82         in->ndigi = k;
  83
  84         ax25_digi_invert(in, out);
  85 }
  86
  87 void ax25_rt_device_down(struct net_device *dev)
  88 {
  89         ax25_route *s, *t, *ax25_rt = ax25_route_list;
  90
  91         while (ax25_rt != NULL) {
  92                 s       = ax25_rt;
  93                 ax25_rt = ax25_rt->next;
  94
  95                 if (s->dev == dev) {
  96                         if (ax25_route_list == s) {
  97                                 ax25_route_list = s->next;
  98                                 if (s->digipeat != NULL)
  99                                         kfree(s->digipeat);
 100                                 kfree(s);
 101                         } else {
 102                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 103                                         if (t->next == s) {
 104                                                 t->next = s->next;
 105                                                 if (s->digipeat != NULL)
 106                                                         kfree(s->digipeat);
 107                                                 kfree(s);
 108                                                 break;
 109                                         }
 110                                 }
 111                         }
 112                 }
 113         }
 114 }
 115
 116 int ax25_rt_ioctl(unsigned int cmd, void *arg)
 117 {
 118         unsigned long flags;
 119         ax25_route *s, *t, *ax25_rt;
 120         struct ax25_routes_struct route;
 121         struct ax25_route_opt_struct rt_option;
 122         ax25_dev *ax25_dev;
 123         int i;
 124
 125         switch (cmd) {
 126                 case SIOCADDRT:
 127                         if (copy_from_user(&route, arg, sizeof(route)))
 128                                 return -EFAULT;
 129                         if ((ax25_dev = ax25_addr_ax25dev(&route.port_addr)) == NULL)
 130                                 return -EINVAL;
 131                         if (route.digi_count > AX25_MAX_DIGIS)
 132                                 return -EINVAL;
 133                         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 134                                 if (ax25cmp(&ax25_rt->callsign, &route.dest_addr) == 0 && ax25_rt->dev == ax25_dev->dev) {
 135                                         if (ax25_rt->digipeat != NULL) {
 136                                                 kfree(ax25_rt->digipeat);
 137                                                 ax25_rt->digipeat = NULL;
 138                                         }
 139                                         if (route.digi_count != 0) {
 140                                                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL)
 141                                                         return -ENOMEM;
 142                                                 ax25_rt->digipeat->lastrepeat = -1;
 143                                                 ax25_rt->digipeat->ndigi      = route.digi_count;
 144                                                 for (i = 0; i < route.digi_count; i++) {
 145                                                         ax25_rt->digipeat->repeated[i] = 0;
 146                                                         ax25_rt->digipeat->calls[i]    = route.digi_addr[i];
 147                                                 }
 148                                         }
 149                                         return 0;
 150                                 }
 151                         }
 152                         if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL)
 153                                 return -ENOMEM;
 154                         ax25_rt->callsign     = route.dest_addr;
 155                         ax25_rt->dev          = ax25_dev->dev;
 156                         ax25_rt->digipeat     = NULL;
 157                         ax25_rt->ip_mode      = ' ';
 158                         if (route.digi_count != 0) {
 159                                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 160                                         kfree(ax25_rt);
 161                                         return -ENOMEM;
 162                                 }
 163                                 ax25_rt->digipeat->lastrepeat = -1;
 164                                 ax25_rt->digipeat->ndigi      = route.digi_count;
 165                                 for (i = 0; i < route.digi_count; i++) {
 166                                         ax25_rt->digipeat->repeated[i] = 0;
 167                                         ax25_rt->digipeat->calls[i]    = route.digi_addr[i];
 168                                 }
 169                         }
 170                         save_flags(flags); cli();
 171                         ax25_rt->next   = ax25_route_list;
 172                         ax25_route_list = ax25_rt;
 173                         restore_flags(flags);
 174                         break;
 175
 176                 case SIOCDELRT:
 177                         if (copy_from_user(&route, arg, sizeof(route)))
 178                                 return -EFAULT;
 179                         if ((ax25_dev = ax25_addr_ax25dev(&route.port_addr)) == NULL)
 180                                 return -EINVAL;
 181                         ax25_rt = ax25_route_list;
 182                         while (ax25_rt != NULL) {
 183                                 s       = ax25_rt;
 184                                 ax25_rt = ax25_rt->next;
 185                                 if (s->dev == ax25_dev->dev && ax25cmp(&route.dest_addr, &s->callsign) == 0) {
 186                                         if (ax25_route_list == s) {
 187                                                 ax25_route_list = s->next;
 188                                                 if (s->digipeat != NULL)
 189                                                         kfree(s->digipeat);
 190                                                 kfree(s);
 191                                         } else {
 192                                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 193                                                         if (t->next == s) {
 194                                                                 t->next = s->next;
 195                                                                 if (s->digipeat != NULL)
 196                                                                         kfree(s->digipeat);
 197                                                                 kfree(s);
 198                                                                 break;
 199                                                         }
 200                                                 }
 201                                         }
 202                                 }
 203                         }
 204                         break;
 205
 206                 case SIOCAX25OPTRT:
 207                         if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 208                                 return -EFAULT;
 209                         if ((ax25_dev = ax25_addr_ax25dev(&rt_option.port_addr)) == NULL)
 210                                 return -EINVAL;
 211                         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 212                                 if (ax25_rt->dev == ax25_dev->dev && ax25cmp(&rt_option.dest_addr, &ax25_rt->callsign) == 0) {
 213                                         switch (rt_option.cmd) {
 214                                                 case AX25_SET_RT_IPMODE:
 215                                                         switch (rt_option.arg) {
 216                                                                 case ' ':
 217                                                                 case 'D':
 218                                                                 case 'V':
 219                                                                         ax25_rt->ip_mode = rt_option.arg;
 220                                                                         break;
 221                                                                 default:
 222                                                                         return -EINVAL;
 223                                                         }
 224                                                         break;
 225                                                 default:
 226                                                         return -EINVAL;
 227                                         }
 228                                 }
 229                         }
 230                         break;
 231
 232                 default:
 233                         return -EINVAL;
 234         }
 235
 236         return 0;
 237 }
 238
 239 int ax25_rt_get_info(char *buffer, char **start, off_t offset, int length)
 240 {
 241         ax25_route *ax25_rt;
 242         int len     = 0;
 243         off_t pos   = 0;
 244         off_t begin = 0;
 245         char *callsign;
 246         int i;
 247
 248         cli();
 249
 250         len += sprintf(buffer, "callsign  dev  mode digipeaters\n");
 251
 252         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 253                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 254                         callsign = "default";
 255                 else
 256                         callsign = ax2asc(&ax25_rt->callsign);
 257                 len += sprintf(buffer + len, "%-9s %-4s",
 258                         callsign,
 259                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 260
 261                 switch (ax25_rt->ip_mode) {
 262                         case 'V':
 263                                 len += sprintf(buffer + len, "   vc");
 264                                 break;
 265                         case 'D':
 266                                 len += sprintf(buffer + len, "   dg");
 267                                 break;
 268                         default:
 269                                 len += sprintf(buffer + len, "    *");
 270                                 break;
 271                 }
 272
 273                 if (ax25_rt->digipeat != NULL)
 274                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 275                                 len += sprintf(buffer + len, " %s", ax2asc(&ax25_rt->digipeat->calls[i]));
 276
 277                 len += sprintf(buffer + len, "\n");
 278
 279                 pos = begin + len;
 280
 281                 if (pos < offset) {
 282                         len   = 0;
 283                         begin = pos;
 284                 }
 285
 286                 if (pos > offset + length)
 287                         break;
 288         }
 289
 290         sti();
 291
 292         *start = buffer + (offset - begin);
 293         len   -= (offset - begin);
 294
 295         if (len > length) len = length;
 296
 297         return len;
 298 }
 299
 300 /*
 301  *      Find AX.25 route
 302  */
 303 static ax25_route *ax25_find_route(ax25_address *addr, struct net_device *dev)
 304 {
 305         ax25_route *ax25_spe_rt = NULL;
 306         ax25_route *ax25_def_rt = NULL;
 307         ax25_route *ax25_rt;
 308
 309         /*
 310          *      Bind to the physical interface we heard them on, or the default
 311          *      route if none is found;
 312          */
 313         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 314                 if (dev == NULL) {
 315                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 316                                 ax25_spe_rt = ax25_rt;
 317                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 318                                 ax25_def_rt = ax25_rt;
 319                 } else {
 320                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 321                                 ax25_spe_rt = ax25_rt;
 322                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 323                                 ax25_def_rt = ax25_rt;
 324                 }
 325         }
 326
 327         if (ax25_spe_rt != NULL)
 328                 return ax25_spe_rt;
 329
 330         return ax25_def_rt;
 331 }
 332
 333 /*
 334  *      Adjust path: If you specify a default route and want to connect
 335  *      a target on the digipeater path but w/o having a special route
 336  *      set before, the path has to be truncated from your target on.
 337  */
 338 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 339 {
 340         int k;
 341
 342         for (k = 0; k < digipeat->ndigi; k++) {
 343                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 344                         break;
 345         }
 346
 347         digipeat->ndigi = k;
 348 }
 349
 350
 351 /*
 352  *      Find which interface to use.
 353  */
 354 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 355 {
 356         ax25_route *ax25_rt;
 357         ax25_address *call;
 358
 359         if ((ax25_rt = ax25_find_route(addr, NULL)) == NULL)
 360                 return -EHOSTUNREACH;
 361
 362         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL)
 363                 return -EHOSTUNREACH;
 364
 365         if ((call = ax25_findbyuid(current->euid)) == NULL) {
 366                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE))
 367                         return -EPERM;
 368                 call = (ax25_address *)ax25->ax25_dev->dev->dev_addr;
 369         }
 370
 371         ax25->source_addr = *call;
 372
 373         if (ax25_rt->digipeat != NULL) {
 374                 if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL)
 375                         return -ENOMEM;
 376                 memcpy(ax25->digipeat, ax25_rt->digipeat, sizeof(ax25_digi));
 377                 ax25_adjust_path(addr, ax25->digipeat);
 378         }
 379
 380         if (ax25->sk != NULL)
 381                 ax25->sk->zapped = 0;
 382
 383         return 0;
 384 }
 385
 386 /*
 387  *      dl1bke 960117: build digipeater path
 388  *      dl1bke 960301: use the default route if it exists
 389  */
 390 ax25_route *ax25_rt_find_route(ax25_address *addr, struct net_device *dev)
 391 {
 392         static ax25_route route;
 393         ax25_route *ax25_rt;
 394
 395         if ((ax25_rt = ax25_find_route(addr, dev)) == NULL) {
 396                 route.next     = NULL;
 397                 route.callsign = *addr;
 398                 route.dev      = dev;
 399                 route.digipeat = NULL;
 400                 route.ip_mode  = ' ';
 401                 return &route;
 402         }
 403
 404         return ax25_rt;
 405 }
 406
 407 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src, ax25_address *dest, ax25_digi *digi)
 408 {
 409         struct sk_buff *skbn;
 410         unsigned char *bp;
 411         int len;
 412
 413         len = digi->ndigi * AX25_ADDR_LEN;
 414
 415         if (skb_headroom(skb) < len) {
 416                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
 417                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 418                         return NULL;
 419                 }
 420
 421                 if (skb->sk != NULL)
 422                         skb_set_owner_w(skbn, skb->sk);
 423
 424                 kfree_skb(skb);
 425
 426                 skb = skbn;
 427         }
 428
 429         bp = skb_push(skb, len);
 430
 431         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 432
 433         return skb;
 434 }
 435
 436 /*
 437  *      Free all memory associated with routing structures.
 438  */
 439 void __exit ax25_rt_free(void)
 440 {
 441         ax25_route *s, *ax25_rt = ax25_route_list;
 442
 443         while (ax25_rt != NULL) {
 444                 s       = ax25_rt;
 445                 ax25_rt = ax25_rt->next;
 446
 447                 if (s->digipeat != NULL)
 448                         kfree(s->digipeat);
 449
 450                 kfree(s);
 451         }
 452 }