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 (route->digi_count > AX25_MAX_DIGIS)
  79                 return -EINVAL;
  80
  81         ax25_dev = ax25_addr_ax25dev(&route->port_addr);
  82         if (!ax25_dev)
  83                 return -EINVAL;
  84
  85         write_lock_bh(&ax25_route_lock);
  86
  87         ax25_rt = ax25_route_list;
  88         while (ax25_rt != NULL) {
  89                 if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
  90                             ax25_rt->dev == ax25_dev->dev) {
  91                         kfree(ax25_rt->digipeat);
  92                         ax25_rt->digipeat = NULL;
  93                         if (route->digi_count != 0) {
  94                                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
  95                                         write_unlock_bh(&ax25_route_lock);
  96                                         ax25_dev_put(ax25_dev);
  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                         ax25_dev_put(ax25_dev);
 108                         return 0;
 109                 }
 110                 ax25_rt = ax25_rt->next;
 111         }
 112
 113         if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
 114                 write_unlock_bh(&ax25_route_lock);
 115                 ax25_dev_put(ax25_dev);
 116                 return -ENOMEM;
 117         }
 118
 119         ax25_rt->callsign     = route->dest_addr;
 120         ax25_rt->dev          = ax25_dev->dev;
 121         ax25_rt->digipeat     = NULL;
 122         ax25_rt->ip_mode      = ' ';
 123         if (route->digi_count != 0) {
 124                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 125                         write_unlock_bh(&ax25_route_lock);
 126                         kfree(ax25_rt);
 127                         ax25_dev_put(ax25_dev);
 128                         return -ENOMEM;
 129                 }
 130                 ax25_rt->digipeat->lastrepeat = -1;
 131                 ax25_rt->digipeat->ndigi      = route->digi_count;
 132                 for (i = 0; i < route->digi_count; i++) {
 133                         ax25_rt->digipeat->repeated[i] = 0;
 134                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 135                 }
 136         }
 137         ax25_rt->next   = ax25_route_list;
 138         ax25_route_list = ax25_rt;
 139         write_unlock_bh(&ax25_route_lock);
 140         ax25_dev_put(ax25_dev);
 141
 142         return 0;
 143 }
 144
 145 void __ax25_put_route(ax25_route *ax25_rt)
 146 {
 147         kfree(ax25_rt->digipeat);
 148         kfree(ax25_rt);
 149 }
 150
 151 static int ax25_rt_del(struct ax25_routes_struct *route)
 152 {
 153         ax25_route *s, *t, *ax25_rt;
 154         ax25_dev *ax25_dev;
 155
 156         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
 157                 return -EINVAL;
 158
 159         write_lock_bh(&ax25_route_lock);
 160
 161         ax25_rt = ax25_route_list;
 162         while (ax25_rt != NULL) {
 163                 s       = ax25_rt;
 164                 ax25_rt = ax25_rt->next;
 165                 if (s->dev == ax25_dev->dev &&
 166                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
 167                         if (ax25_route_list == s) {
 168                                 ax25_route_list = s->next;
 169                                 __ax25_put_route(s);
 170                         } else {
 171                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 172                                         if (t->next == s) {
 173                                                 t->next = s->next;
 174                                                 __ax25_put_route(s);
 175                                                 break;
 176                                         }
 177                                 }
 178                         }
 179                 }
 180         }
 181         write_unlock_bh(&ax25_route_lock);
 182         ax25_dev_put(ax25_dev);
 183
 184         return 0;
 185 }
 186
 187 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
 188 {
 189         ax25_route *ax25_rt;
 190         ax25_dev *ax25_dev;
 191         int err = 0;
 192
 193         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
 194                 return -EINVAL;
 195
 196         write_lock_bh(&ax25_route_lock);
 197
 198         ax25_rt = ax25_route_list;
 199         while (ax25_rt != NULL) {
 200                 if (ax25_rt->dev == ax25_dev->dev &&
 201                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
 202                         switch (rt_option->cmd) {
 203                         case AX25_SET_RT_IPMODE:
 204                                 switch (rt_option->arg) {
 205                                 case ' ':
 206                                 case 'D':
 207                                 case 'V':
 208                                         ax25_rt->ip_mode = rt_option->arg;
 209                                         break;
 210                                 default:
 211                                         err = -EINVAL;
 212                                         goto out;
 213                                 }
 214                                 break;
 215                         default:
 216                                 err = -EINVAL;
 217                                 goto out;
 218                         }
 219                 }
 220                 ax25_rt = ax25_rt->next;
 221         }
 222
 223 out:
 224         write_unlock_bh(&ax25_route_lock);
 225         ax25_dev_put(ax25_dev);
 226         return err;
 227 }
 228
 229 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
 230 {
 231         struct ax25_route_opt_struct rt_option;
 232         struct ax25_routes_struct route;
 233
 234         switch (cmd) {
 235         case SIOCADDRT:
 236                 if (copy_from_user(&route, arg, sizeof(route)))
 237                         return -EFAULT;
 238                 return ax25_rt_add(&route);
 239
 240         case SIOCDELRT:
 241                 if (copy_from_user(&route, arg, sizeof(route)))
 242                         return -EFAULT;
 243                 return ax25_rt_del(&route);
 244
 245         case SIOCAX25OPTRT:
 246                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 247                         return -EFAULT;
 248                 return ax25_rt_opt(&rt_option);
 249
 250         default:
 251                 return -EINVAL;
 252         }
 253 }
 254
 255 #ifdef CONFIG_PROC_FS
 256
 257 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
 258         __acquires(ax25_route_lock)
 259 {
 260         struct ax25_route *ax25_rt;
 261         int i = 1;
 262
 263         read_lock(&ax25_route_lock);
 264         if (*pos == 0)
 265                 return SEQ_START_TOKEN;
 266
 267         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 268                 if (i == *pos)
 269                         return ax25_rt;
 270                 ++i;
 271         }
 272
 273         return NULL;
 274 }
 275
 276 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 277 {
 278         ++*pos;
 279         return (v == SEQ_START_TOKEN) ? ax25_route_list :
 280                 ((struct ax25_route *) v)->next;
 281 }
 282
 283 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
 284         __releases(ax25_route_lock)
 285 {
 286         read_unlock(&ax25_route_lock);
 287 }
 288
 289 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
 290 {
 291         char buf[11];
 292
 293         if (v == SEQ_START_TOKEN)
 294                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 295         else {
 296                 struct ax25_route *ax25_rt = v;
 297                 const char *callsign;
 298                 int i;
 299
 300                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 301                         callsign = "default";
 302                 else
 303                         callsign = ax2asc(buf, &ax25_rt->callsign);
 304
 305                 seq_printf(seq, "%-9s %-4s",
 306                         callsign,
 307                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 308
 309                 switch (ax25_rt->ip_mode) {
 310                 case 'V':
 311                         seq_puts(seq, "   vc");
 312                         break;
 313                 case 'D':
 314                         seq_puts(seq, "   dg");
 315                         break;
 316                 default:
 317                         seq_puts(seq, "    *");
 318                         break;
 319                 }
 320
 321                 if (ax25_rt->digipeat != NULL)
 322                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 323                                 seq_printf(seq, " %s",
 324                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
 325
 326                 seq_puts(seq, "\n");
 327         }
 328         return 0;
 329 }
 330
 331 const struct seq_operations ax25_rt_seqops = {
 332         .start = ax25_rt_seq_start,
 333         .next = ax25_rt_seq_next,
 334         .stop = ax25_rt_seq_stop,
 335         .show = ax25_rt_seq_show,
 336 };
 337 #endif
 338
 339 /*
 340  *      Find AX.25 route
 341  *
 342  *      Only routes with a reference count of zero can be destroyed.
 343  *      Must be called with ax25_route_lock read locked.
 344  */
 345 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 346 {
 347         ax25_route *ax25_spe_rt = NULL;
 348         ax25_route *ax25_def_rt = NULL;
 349         ax25_route *ax25_rt;
 350
 351         /*
 352          *      Bind to the physical interface we heard them on, or the default
 353          *      route if none is found;
 354          */
 355         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 356                 if (dev == NULL) {
 357                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 358                                 ax25_spe_rt = ax25_rt;
 359                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 360                                 ax25_def_rt = ax25_rt;
 361                 } else {
 362                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 363                                 ax25_spe_rt = ax25_rt;
 364                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 365                                 ax25_def_rt = ax25_rt;
 366                 }
 367         }
 368
 369         ax25_rt = ax25_def_rt;
 370         if (ax25_spe_rt != NULL)
 371                 ax25_rt = ax25_spe_rt;
 372
 373         return ax25_rt;
 374 }
 375
 376 /*
 377  *      Adjust path: If you specify a default route and want to connect
 378  *      a target on the digipeater path but w/o having a special route
 379  *      set before, the path has to be truncated from your target on.
 380  */
 381 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 382 {
 383         int k;
 384
 385         for (k = 0; k < digipeat->ndigi; k++) {
 386                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 387                         break;
 388         }
 389
 390         digipeat->ndigi = k;
 391 }
 392
 393
 394 /*
 395  *      Find which interface to use.
 396  */
 397 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 398 {
 399         ax25_uid_assoc *user;
 400         ax25_route *ax25_rt;
 401         int err = 0;
 402
 403         ax25_route_lock_use();
 404         ax25_rt = ax25_get_route(addr, NULL);
 405         if (!ax25_rt) {
 406                 ax25_route_lock_unuse();
 407                 return -EHOSTUNREACH;
 408         }
 409         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 410                 err = -EHOSTUNREACH;
 411                 goto put;
 412         }
 413
 414         user = ax25_findbyuid(current_euid());
 415         if (user) {
 416                 ax25->source_addr = user->call;
 417                 ax25_uid_put(user);
 418         } else {
 419                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 420                         err = -EPERM;
 421                         goto put;
 422                 }
 423                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
 424         }
 425
 426         if (ax25_rt->digipeat != NULL) {
 427                 ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
 428                                          GFP_ATOMIC);
 429                 if (ax25->digipeat == NULL) {
 430                         err = -ENOMEM;
 431                         goto put;
 432                 }
 433                 ax25_adjust_path(addr, ax25->digipeat);
 434         }
 435
 436         if (ax25->sk != NULL) {
 437                 local_bh_disable();
 438                 bh_lock_sock(ax25->sk);
 439                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 440                 bh_unlock_sock(ax25->sk);
 441                 local_bh_enable();
 442         }
 443
 444 put:
 445         ax25_route_lock_unuse();
 446         return err;
 447 }
 448
 449 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 450         ax25_address *dest, ax25_digi *digi)
 451 {
 452         unsigned char *bp;
 453         int len;
 454
 455         len = digi->ndigi * AX25_ADDR_LEN;
 456
 457         if (unlikely(skb_headroom(skb) < len)) {
 458                 skb = skb_expand_head(skb, len);
 459                 if (!skb) {
 460                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 461                         return NULL;
 462                 }
 463         }
 464
 465         bp = skb_push(skb, len);
 466
 467         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 468
 469         return skb;
 470 }
 471
 472 /*
 473  *      Free all memory associated with routing structures.
 474  */
 475 void __exit ax25_rt_free(void)
 476 {
 477         ax25_route *s, *ax25_rt = ax25_route_list;
 478
 479         write_lock_bh(&ax25_route_lock);
 480         while (ax25_rt != NULL) {
 481                 s       = ax25_rt;
 482                 ax25_rt = ax25_rt->next;
 483
 484                 kfree(s->digipeat);
 485                 kfree(s);
 486         }
 487         write_unlock_bh(&ax25_route_lock);
 488 }