net/ax25/ax25_route.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *
   4  * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
   5  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   6  * Copyright (C) Steven Whitehouse GW7RRM (stevew@acm.org)
   7  * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
   8  * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
   9  * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
  10  */
  11
  12 #include <linux/capability.h>
  13 #include <linux/errno.h>
  14 #include <linux/types.h>
  15 #include <linux/socket.h>
  16 #include <linux/timer.h>
  17 #include <linux/in.h>
  18 #include <linux/kernel.h>
  19 #include <linux/sched.h>
  20 #include <linux/string.h>
  21 #include <linux/sockios.h>
  22 #include <linux/net.h>
  23 #include <linux/slab.h>
  24 #include <net/ax25.h>
  25 #include <linux/inet.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/if_arp.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/spinlock.h>
  30 #include <net/sock.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/fcntl.h>
  33 #include <linux/mm.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/init.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/export.h>
  38
  39 static ax25_route *ax25_route_list;
  40 DEFINE_RWLOCK(ax25_route_lock);
  41
  42 void ax25_rt_device_down(struct net_device *dev)
  43 {
  44         ax25_route *s, *t, *ax25_rt;
  45
  46         write_lock_bh(&ax25_route_lock);
  47         ax25_rt = ax25_route_list;
  48         while (ax25_rt != NULL) {
  49                 s       = ax25_rt;
  50                 ax25_rt = ax25_rt->next;
  51
  52                 if (s->dev == dev) {
  53                         if (ax25_route_list == s) {
  54                                 ax25_route_list = s->next;
  55                                 kfree(s->digipeat);
  56                                 kfree(s);
  57                         } else {
  58                                 for (t = ax25_route_list; t != NULL; t = t->next) {
  59                                         if (t->next == s) {
  60                                                 t->next = s->next;
  61                                                 kfree(s->digipeat);
  62                                                 kfree(s);
  63                                                 break;
  64                                         }
  65                                 }
  66                         }
  67                 }
  68         }
  69         write_unlock_bh(&ax25_route_lock);
  70 }
  71
  72 static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
  73 {
  74         ax25_route *ax25_rt;
  75         ax25_dev *ax25_dev;
  76         int i;
  77
  78         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
  79                 return -EINVAL;
  80         if (route->digi_count > AX25_MAX_DIGIS)
  81                 return -EINVAL;
  82
  83         write_lock_bh(&ax25_route_lock);
  84
  85         ax25_rt = ax25_route_list;
  86         while (ax25_rt != NULL) {
  87                 if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
  88                             ax25_rt->dev == ax25_dev->dev) {
  89                         kfree(ax25_rt->digipeat);
  90                         ax25_rt->digipeat = NULL;
  91                         if (route->digi_count != 0) {
  92                                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
  93                                         write_unlock_bh(&ax25_route_lock);
  94                                         return -ENOMEM;
  95                                 }
  96                                 ax25_rt->digipeat->lastrepeat = -1;
  97                                 ax25_rt->digipeat->ndigi      = route->digi_count;
  98                                 for (i = 0; i < route->digi_count; i++) {
  99                                         ax25_rt->digipeat->repeated[i] = 0;
 100                                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 101                                 }
 102                         }
 103                         write_unlock_bh(&ax25_route_lock);
 104                         return 0;
 105                 }
 106                 ax25_rt = ax25_rt->next;
 107         }
 108
 109         if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
 110                 write_unlock_bh(&ax25_route_lock);
 111                 return -ENOMEM;
 112         }
 113
 114         refcount_set(&ax25_rt->refcount, 1);
 115         ax25_rt->callsign     = route->dest_addr;
 116         ax25_rt->dev          = ax25_dev->dev;
 117         ax25_rt->digipeat     = NULL;
 118         ax25_rt->ip_mode      = ' ';
 119         if (route->digi_count != 0) {
 120                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 121                         write_unlock_bh(&ax25_route_lock);
 122                         kfree(ax25_rt);
 123                         return -ENOMEM;
 124                 }
 125                 ax25_rt->digipeat->lastrepeat = -1;
 126                 ax25_rt->digipeat->ndigi      = route->digi_count;
 127                 for (i = 0; i < route->digi_count; i++) {
 128                         ax25_rt->digipeat->repeated[i] = 0;
 129                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 130                 }
 131         }
 132         ax25_rt->next   = ax25_route_list;
 133         ax25_route_list = ax25_rt;
 134         write_unlock_bh(&ax25_route_lock);
 135
 136         return 0;
 137 }
 138
 139 void __ax25_put_route(ax25_route *ax25_rt)
 140 {
 141         kfree(ax25_rt->digipeat);
 142         kfree(ax25_rt);
 143 }
 144
 145 static int ax25_rt_del(struct ax25_routes_struct *route)
 146 {
 147         ax25_route *s, *t, *ax25_rt;
 148         ax25_dev *ax25_dev;
 149
 150         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
 151                 return -EINVAL;
 152
 153         write_lock_bh(&ax25_route_lock);
 154
 155         ax25_rt = ax25_route_list;
 156         while (ax25_rt != NULL) {
 157                 s       = ax25_rt;
 158                 ax25_rt = ax25_rt->next;
 159                 if (s->dev == ax25_dev->dev &&
 160                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
 161                         if (ax25_route_list == s) {
 162                                 ax25_route_list = s->next;
 163                                 ax25_put_route(s);
 164                         } else {
 165                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 166                                         if (t->next == s) {
 167                                                 t->next = s->next;
 168                                                 ax25_put_route(s);
 169                                                 break;
 170                                         }
 171                                 }
 172                         }
 173                 }
 174         }
 175         write_unlock_bh(&ax25_route_lock);
 176
 177         return 0;
 178 }
 179
 180 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
 181 {
 182         ax25_route *ax25_rt;
 183         ax25_dev *ax25_dev;
 184         int err = 0;
 185
 186         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
 187                 return -EINVAL;
 188
 189         write_lock_bh(&ax25_route_lock);
 190
 191         ax25_rt = ax25_route_list;
 192         while (ax25_rt != NULL) {
 193                 if (ax25_rt->dev == ax25_dev->dev &&
 194                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
 195                         switch (rt_option->cmd) {
 196                         case AX25_SET_RT_IPMODE:
 197                                 switch (rt_option->arg) {
 198                                 case ' ':
 199                                 case 'D':
 200                                 case 'V':
 201                                         ax25_rt->ip_mode = rt_option->arg;
 202                                         break;
 203                                 default:
 204                                         err = -EINVAL;
 205                                         goto out;
 206                                 }
 207                                 break;
 208                         default:
 209                                 err = -EINVAL;
 210                                 goto out;
 211                         }
 212                 }
 213                 ax25_rt = ax25_rt->next;
 214         }
 215
 216 out:
 217         write_unlock_bh(&ax25_route_lock);
 218         return err;
 219 }
 220
 221 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
 222 {
 223         struct ax25_route_opt_struct rt_option;
 224         struct ax25_routes_struct route;
 225
 226         switch (cmd) {
 227         case SIOCADDRT:
 228                 if (copy_from_user(&route, arg, sizeof(route)))
 229                         return -EFAULT;
 230                 return ax25_rt_add(&route);
 231
 232         case SIOCDELRT:
 233                 if (copy_from_user(&route, arg, sizeof(route)))
 234                         return -EFAULT;
 235                 return ax25_rt_del(&route);
 236
 237         case SIOCAX25OPTRT:
 238                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 239                         return -EFAULT;
 240                 return ax25_rt_opt(&rt_option);
 241
 242         default:
 243                 return -EINVAL;
 244         }
 245 }
 246
 247 #ifdef CONFIG_PROC_FS
 248
 249 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
 250         __acquires(ax25_route_lock)
 251 {
 252         struct ax25_route *ax25_rt;
 253         int i = 1;
 254
 255         read_lock(&ax25_route_lock);
 256         if (*pos == 0)
 257                 return SEQ_START_TOKEN;
 258
 259         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 260                 if (i == *pos)
 261                         return ax25_rt;
 262                 ++i;
 263         }
 264
 265         return NULL;
 266 }
 267
 268 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 269 {
 270         ++*pos;
 271         return (v == SEQ_START_TOKEN) ? ax25_route_list :
 272                 ((struct ax25_route *) v)->next;
 273 }
 274
 275 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
 276         __releases(ax25_route_lock)
 277 {
 278         read_unlock(&ax25_route_lock);
 279 }
 280
 281 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
 282 {
 283         char buf[11];
 284
 285         if (v == SEQ_START_TOKEN)
 286                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 287         else {
 288                 struct ax25_route *ax25_rt = v;
 289                 const char *callsign;
 290                 int i;
 291
 292                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 293                         callsign = "default";
 294                 else
 295                         callsign = ax2asc(buf, &ax25_rt->callsign);
 296
 297                 seq_printf(seq, "%-9s %-4s",
 298                         callsign,
 299                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 300
 301                 switch (ax25_rt->ip_mode) {
 302                 case 'V':
 303                         seq_puts(seq, "   vc");
 304                         break;
 305                 case 'D':
 306                         seq_puts(seq, "   dg");
 307                         break;
 308                 default:
 309                         seq_puts(seq, "    *");
 310                         break;
 311                 }
 312
 313                 if (ax25_rt->digipeat != NULL)
 314                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 315                                 seq_printf(seq, " %s",
 316                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
 317
 318                 seq_puts(seq, "\n");
 319         }
 320         return 0;
 321 }
 322
 323 const struct seq_operations ax25_rt_seqops = {
 324         .start = ax25_rt_seq_start,
 325         .next = ax25_rt_seq_next,
 326         .stop = ax25_rt_seq_stop,
 327         .show = ax25_rt_seq_show,
 328 };
 329 #endif
 330
 331 /*
 332  *      Find AX.25 route
 333  *
 334  *      Only routes with a reference count of zero can be destroyed.
 335  *      Must be called with ax25_route_lock read locked.
 336  */
 337 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 338 {
 339         ax25_route *ax25_spe_rt = NULL;
 340         ax25_route *ax25_def_rt = NULL;
 341         ax25_route *ax25_rt;
 342
 343         /*
 344          *      Bind to the physical interface we heard them on, or the default
 345          *      route if none is found;
 346          */
 347         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 348                 if (dev == NULL) {
 349                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 350                                 ax25_spe_rt = ax25_rt;
 351                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 352                                 ax25_def_rt = ax25_rt;
 353                 } else {
 354                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 355                                 ax25_spe_rt = ax25_rt;
 356                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 357                                 ax25_def_rt = ax25_rt;
 358                 }
 359         }
 360
 361         ax25_rt = ax25_def_rt;
 362         if (ax25_spe_rt != NULL)
 363                 ax25_rt = ax25_spe_rt;
 364
 365         return ax25_rt;
 366 }
 367
 368 /*
 369  *      Adjust path: If you specify a default route and want to connect
 370  *      a target on the digipeater path but w/o having a special route
 371  *      set before, the path has to be truncated from your target on.
 372  */
 373 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 374 {
 375         int k;
 376
 377         for (k = 0; k < digipeat->ndigi; k++) {
 378                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 379                         break;
 380         }
 381
 382         digipeat->ndigi = k;
 383 }
 384
 385
 386 /*
 387  *      Find which interface to use.
 388  */
 389 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 390 {
 391         ax25_uid_assoc *user;
 392         ax25_route *ax25_rt;
 393         int err = 0;
 394
 395         ax25_route_lock_use();
 396         ax25_rt = ax25_get_route(addr, NULL);
 397         if (!ax25_rt) {
 398                 ax25_route_lock_unuse();
 399                 return -EHOSTUNREACH;
 400         }
 401         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 402                 err = -EHOSTUNREACH;
 403                 goto put;
 404         }
 405
 406         user = ax25_findbyuid(current_euid());
 407         if (user) {
 408                 ax25->source_addr = user->call;
 409                 ax25_uid_put(user);
 410         } else {
 411                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 412                         err = -EPERM;
 413                         goto put;
 414                 }
 415                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
 416         }
 417
 418         if (ax25_rt->digipeat != NULL) {
 419                 ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
 420                                          GFP_ATOMIC);
 421                 if (ax25->digipeat == NULL) {
 422                         err = -ENOMEM;
 423                         goto put;
 424                 }
 425                 ax25_adjust_path(addr, ax25->digipeat);
 426         }
 427
 428         if (ax25->sk != NULL) {
 429                 local_bh_disable();
 430                 bh_lock_sock(ax25->sk);
 431                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 432                 bh_unlock_sock(ax25->sk);
 433                 local_bh_enable();
 434         }
 435
 436 put:
 437         ax25_route_lock_unuse();
 438         return err;
 439 }
 440
 441 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 442         ax25_address *dest, ax25_digi *digi)
 443 {
 444         struct sk_buff *skbn;
 445         unsigned char *bp;
 446         int len;
 447
 448         len = digi->ndigi * AX25_ADDR_LEN;
 449
 450         if (skb_headroom(skb) < len) {
 451                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
 452                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 453                         return NULL;
 454                 }
 455
 456                 if (skb->sk != NULL)
 457                         skb_set_owner_w(skbn, skb->sk);
 458
 459                 consume_skb(skb);
 460
 461                 skb = skbn;
 462         }
 463
 464         bp = skb_push(skb, len);
 465
 466         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 467
 468         return skb;
 469 }
 470
 471 /*
 472  *      Free all memory associated with routing structures.
 473  */
 474 void __exit ax25_rt_free(void)
 475 {
 476         ax25_route *s, *ax25_rt = ax25_route_list;
 477
 478         write_lock_bh(&ax25_route_lock);
 479         while (ax25_rt != NULL) {
 480                 s       = ax25_rt;
 481                 ax25_rt = ax25_rt->next;
 482
 483                 kfree(s->digipeat);
 484                 kfree(s);
 485         }
 486         write_unlock_bh(&ax25_route_lock);
 487 }