net/ax25/ax25_route.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
   8  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   9  * Copyright (C) Steven Whitehouse GW7RRM (stevew@acm.org)
  10  * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
  11  * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
  12  * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
  13  */
  14
  15 #include <linux/capability.h>
  16 #include <linux/errno.h>
  17 #include <linux/types.h>
  18 #include <linux/socket.h>
  19 #include <linux/timer.h>
  20 #include <linux/in.h>
  21 #include <linux/kernel.h>
  22 #include <linux/sched.h>
  23 #include <linux/string.h>
  24 #include <linux/sockios.h>
  25 #include <linux/net.h>
  26 #include <linux/slab.h>
  27 #include <net/ax25.h>
  28 #include <linux/inet.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/if_arp.h>
  31 #include <linux/skbuff.h>
  32 #include <linux/spinlock.h>
  33 #include <net/sock.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/mm.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/init.h>
  39 #include <linux/seq_file.h>
  40 #include <linux/export.h>
  41
  42 static ax25_route *ax25_route_list;
  43 DEFINE_RWLOCK(ax25_route_lock);
  44
  45 void ax25_rt_device_down(struct net_device *dev)
  46 {
  47         ax25_route *s, *t, *ax25_rt;
  48
  49         write_lock_bh(&ax25_route_lock);
  50         ax25_rt = ax25_route_list;
  51         while (ax25_rt != NULL) {
  52                 s       = ax25_rt;
  53                 ax25_rt = ax25_rt->next;
  54
  55                 if (s->dev == dev) {
  56                         if (ax25_route_list == s) {
  57                                 ax25_route_list = s->next;
  58                                 kfree(s->digipeat);
  59                                 kfree(s);
  60                         } else {
  61                                 for (t = ax25_route_list; t != NULL; t = t->next) {
  62                                         if (t->next == s) {
  63                                                 t->next = s->next;
  64                                                 kfree(s->digipeat);
  65                                                 kfree(s);
  66                                                 break;
  67                                         }
  68                                 }
  69                         }
  70                 }
  71         }
  72         write_unlock_bh(&ax25_route_lock);
  73 }
  74
  75 static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
  76 {
  77         ax25_route *ax25_rt;
  78         ax25_dev *ax25_dev;
  79         int i;
  80
  81         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
  82                 return -EINVAL;
  83         if (route->digi_count > AX25_MAX_DIGIS)
  84                 return -EINVAL;
  85
  86         write_lock_bh(&ax25_route_lock);
  87
  88         ax25_rt = ax25_route_list;
  89         while (ax25_rt != NULL) {
  90                 if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
  91                             ax25_rt->dev == ax25_dev->dev) {
  92                         kfree(ax25_rt->digipeat);
  93                         ax25_rt->digipeat = NULL;
  94                         if (route->digi_count != 0) {
  95                                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
  96                                         write_unlock_bh(&ax25_route_lock);
  97                                         return -ENOMEM;
  98                                 }
  99                                 ax25_rt->digipeat->lastrepeat = -1;
 100                                 ax25_rt->digipeat->ndigi      = route->digi_count;
 101                                 for (i = 0; i < route->digi_count; i++) {
 102                                         ax25_rt->digipeat->repeated[i] = 0;
 103                                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 104                                 }
 105                         }
 106                         write_unlock_bh(&ax25_route_lock);
 107                         return 0;
 108                 }
 109                 ax25_rt = ax25_rt->next;
 110         }
 111
 112         if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
 113                 write_unlock_bh(&ax25_route_lock);
 114                 return -ENOMEM;
 115         }
 116
 117         refcount_set(&ax25_rt->refcount, 1);
 118         ax25_rt->callsign     = route->dest_addr;
 119         ax25_rt->dev          = ax25_dev->dev;
 120         ax25_rt->digipeat     = NULL;
 121         ax25_rt->ip_mode      = ' ';
 122         if (route->digi_count != 0) {
 123                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 124                         write_unlock_bh(&ax25_route_lock);
 125                         kfree(ax25_rt);
 126                         return -ENOMEM;
 127                 }
 128                 ax25_rt->digipeat->lastrepeat = -1;
 129                 ax25_rt->digipeat->ndigi      = route->digi_count;
 130                 for (i = 0; i < route->digi_count; i++) {
 131                         ax25_rt->digipeat->repeated[i] = 0;
 132                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 133                 }
 134         }
 135         ax25_rt->next   = ax25_route_list;
 136         ax25_route_list = ax25_rt;
 137         write_unlock_bh(&ax25_route_lock);
 138
 139         return 0;
 140 }
 141
 142 void __ax25_put_route(ax25_route *ax25_rt)
 143 {
 144         kfree(ax25_rt->digipeat);
 145         kfree(ax25_rt);
 146 }
 147
 148 static int ax25_rt_del(struct ax25_routes_struct *route)
 149 {
 150         ax25_route *s, *t, *ax25_rt;
 151         ax25_dev *ax25_dev;
 152
 153         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
 154                 return -EINVAL;
 155
 156         write_lock_bh(&ax25_route_lock);
 157
 158         ax25_rt = ax25_route_list;
 159         while (ax25_rt != NULL) {
 160                 s       = ax25_rt;
 161                 ax25_rt = ax25_rt->next;
 162                 if (s->dev == ax25_dev->dev &&
 163                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
 164                         if (ax25_route_list == s) {
 165                                 ax25_route_list = s->next;
 166                                 ax25_put_route(s);
 167                         } else {
 168                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 169                                         if (t->next == s) {
 170                                                 t->next = s->next;
 171                                                 ax25_put_route(s);
 172                                                 break;
 173                                         }
 174                                 }
 175                         }
 176                 }
 177         }
 178         write_unlock_bh(&ax25_route_lock);
 179
 180         return 0;
 181 }
 182
 183 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
 184 {
 185         ax25_route *ax25_rt;
 186         ax25_dev *ax25_dev;
 187         int err = 0;
 188
 189         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
 190                 return -EINVAL;
 191
 192         write_lock_bh(&ax25_route_lock);
 193
 194         ax25_rt = ax25_route_list;
 195         while (ax25_rt != NULL) {
 196                 if (ax25_rt->dev == ax25_dev->dev &&
 197                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
 198                         switch (rt_option->cmd) {
 199                         case AX25_SET_RT_IPMODE:
 200                                 switch (rt_option->arg) {
 201                                 case ' ':
 202                                 case 'D':
 203                                 case 'V':
 204                                         ax25_rt->ip_mode = rt_option->arg;
 205                                         break;
 206                                 default:
 207                                         err = -EINVAL;
 208                                         goto out;
 209                                 }
 210                                 break;
 211                         default:
 212                                 err = -EINVAL;
 213                                 goto out;
 214                         }
 215                 }
 216                 ax25_rt = ax25_rt->next;
 217         }
 218
 219 out:
 220         write_unlock_bh(&ax25_route_lock);
 221         return err;
 222 }
 223
 224 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
 225 {
 226         struct ax25_route_opt_struct rt_option;
 227         struct ax25_routes_struct route;
 228
 229         switch (cmd) {
 230         case SIOCADDRT:
 231                 if (copy_from_user(&route, arg, sizeof(route)))
 232                         return -EFAULT;
 233                 return ax25_rt_add(&route);
 234
 235         case SIOCDELRT:
 236                 if (copy_from_user(&route, arg, sizeof(route)))
 237                         return -EFAULT;
 238                 return ax25_rt_del(&route);
 239
 240         case SIOCAX25OPTRT:
 241                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 242                         return -EFAULT;
 243                 return ax25_rt_opt(&rt_option);
 244
 245         default:
 246                 return -EINVAL;
 247         }
 248 }
 249
 250 #ifdef CONFIG_PROC_FS
 251
 252 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
 253         __acquires(ax25_route_lock)
 254 {
 255         struct ax25_route *ax25_rt;
 256         int i = 1;
 257
 258         read_lock(&ax25_route_lock);
 259         if (*pos == 0)
 260                 return SEQ_START_TOKEN;
 261
 262         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 263                 if (i == *pos)
 264                         return ax25_rt;
 265                 ++i;
 266         }
 267
 268         return NULL;
 269 }
 270
 271 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 272 {
 273         ++*pos;
 274         return (v == SEQ_START_TOKEN) ? ax25_route_list :
 275                 ((struct ax25_route *) v)->next;
 276 }
 277
 278 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
 279         __releases(ax25_route_lock)
 280 {
 281         read_unlock(&ax25_route_lock);
 282 }
 283
 284 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
 285 {
 286         char buf[11];
 287
 288         if (v == SEQ_START_TOKEN)
 289                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 290         else {
 291                 struct ax25_route *ax25_rt = v;
 292                 const char *callsign;
 293                 int i;
 294
 295                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 296                         callsign = "default";
 297                 else
 298                         callsign = ax2asc(buf, &ax25_rt->callsign);
 299
 300                 seq_printf(seq, "%-9s %-4s",
 301                         callsign,
 302                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 303
 304                 switch (ax25_rt->ip_mode) {
 305                 case 'V':
 306                         seq_puts(seq, "   vc");
 307                         break;
 308                 case 'D':
 309                         seq_puts(seq, "   dg");
 310                         break;
 311                 default:
 312                         seq_puts(seq, "    *");
 313                         break;
 314                 }
 315
 316                 if (ax25_rt->digipeat != NULL)
 317                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 318                                 seq_printf(seq, " %s",
 319                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
 320
 321                 seq_puts(seq, "\n");
 322         }
 323         return 0;
 324 }
 325
 326 const struct seq_operations ax25_rt_seqops = {
 327         .start = ax25_rt_seq_start,
 328         .next = ax25_rt_seq_next,
 329         .stop = ax25_rt_seq_stop,
 330         .show = ax25_rt_seq_show,
 331 };
 332 #endif
 333
 334 /*
 335  *      Find AX.25 route
 336  *
 337  *      Only routes with a reference count of zero can be destroyed.
 338  *      Must be called with ax25_route_lock read locked.
 339  */
 340 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 341 {
 342         ax25_route *ax25_spe_rt = NULL;
 343         ax25_route *ax25_def_rt = NULL;
 344         ax25_route *ax25_rt;
 345
 346         /*
 347          *      Bind to the physical interface we heard them on, or the default
 348          *      route if none is found;
 349          */
 350         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 351                 if (dev == NULL) {
 352                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 353                                 ax25_spe_rt = ax25_rt;
 354                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 355                                 ax25_def_rt = ax25_rt;
 356                 } else {
 357                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 358                                 ax25_spe_rt = ax25_rt;
 359                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 360                                 ax25_def_rt = ax25_rt;
 361                 }
 362         }
 363
 364         ax25_rt = ax25_def_rt;
 365         if (ax25_spe_rt != NULL)
 366                 ax25_rt = ax25_spe_rt;
 367
 368         return ax25_rt;
 369 }
 370
 371 /*
 372  *      Adjust path: If you specify a default route and want to connect
 373  *      a target on the digipeater path but w/o having a special route
 374  *      set before, the path has to be truncated from your target on.
 375  */
 376 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 377 {
 378         int k;
 379
 380         for (k = 0; k < digipeat->ndigi; k++) {
 381                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 382                         break;
 383         }
 384
 385         digipeat->ndigi = k;
 386 }
 387
 388
 389 /*
 390  *      Find which interface to use.
 391  */
 392 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 393 {
 394         ax25_uid_assoc *user;
 395         ax25_route *ax25_rt;
 396         int err = 0;
 397
 398         ax25_route_lock_use();
 399         ax25_rt = ax25_get_route(addr, NULL);
 400         if (!ax25_rt) {
 401                 ax25_route_lock_unuse();
 402                 return -EHOSTUNREACH;
 403         }
 404         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 405                 err = -EHOSTUNREACH;
 406                 goto put;
 407         }
 408
 409         user = ax25_findbyuid(current_euid());
 410         if (user) {
 411                 ax25->source_addr = user->call;
 412                 ax25_uid_put(user);
 413         } else {
 414                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 415                         err = -EPERM;
 416                         goto put;
 417                 }
 418                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
 419         }
 420
 421         if (ax25_rt->digipeat != NULL) {
 422                 ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
 423                                          GFP_ATOMIC);
 424                 if (ax25->digipeat == NULL) {
 425                         err = -ENOMEM;
 426                         goto put;
 427                 }
 428                 ax25_adjust_path(addr, ax25->digipeat);
 429         }
 430
 431         if (ax25->sk != NULL) {
 432                 local_bh_disable();
 433                 bh_lock_sock(ax25->sk);
 434                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 435                 bh_unlock_sock(ax25->sk);
 436                 local_bh_enable();
 437         }
 438
 439 put:
 440         ax25_route_lock_unuse();
 441         return err;
 442 }
 443
 444 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 445         ax25_address *dest, ax25_digi *digi)
 446 {
 447         struct sk_buff *skbn;
 448         unsigned char *bp;
 449         int len;
 450
 451         len = digi->ndigi * AX25_ADDR_LEN;
 452
 453         if (skb_headroom(skb) < len) {
 454                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
 455                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 456                         return NULL;
 457                 }
 458
 459                 if (skb->sk != NULL)
 460                         skb_set_owner_w(skbn, skb->sk);
 461
 462                 consume_skb(skb);
 463
 464                 skb = skbn;
 465         }
 466
 467         bp = skb_push(skb, len);
 468
 469         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 470
 471         return skb;
 472 }
 473
 474 /*
 475  *      Free all memory associated with routing structures.
 476  */
 477 void __exit ax25_rt_free(void)
 478 {
 479         ax25_route *s, *ax25_rt = ax25_route_list;
 480
 481         write_lock_bh(&ax25_route_lock);
 482         while (ax25_rt != NULL) {
 483                 s       = ax25_rt;
 484                 ax25_rt = ax25_rt->next;
 485
 486                 kfree(s->digipeat);
 487                 kfree(s);
 488         }
 489         write_unlock_bh(&ax25_route_lock);
 490 }