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         refcount_set(&ax25_rt->refcount, 1);
 120         ax25_rt->callsign     = route->dest_addr;
 121         ax25_rt->dev          = ax25_dev->dev;
 122         ax25_rt->digipeat     = NULL;
 123         ax25_rt->ip_mode      = ' ';
 124         if (route->digi_count != 0) {
 125                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 126                         write_unlock_bh(&ax25_route_lock);
 127                         kfree(ax25_rt);
 128                         ax25_dev_put(ax25_dev);
 129                         return -ENOMEM;
 130                 }
 131                 ax25_rt->digipeat->lastrepeat = -1;
 132                 ax25_rt->digipeat->ndigi      = route->digi_count;
 133                 for (i = 0; i < route->digi_count; i++) {
 134                         ax25_rt->digipeat->repeated[i] = 0;
 135                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 136                 }
 137         }
 138         ax25_rt->next   = ax25_route_list;
 139         ax25_route_list = ax25_rt;
 140         write_unlock_bh(&ax25_route_lock);
 141         ax25_dev_put(ax25_dev);
 142
 143         return 0;
 144 }
 145
 146 void __ax25_put_route(ax25_route *ax25_rt)
 147 {
 148         kfree(ax25_rt->digipeat);
 149         kfree(ax25_rt);
 150 }
 151
 152 static int ax25_rt_del(struct ax25_routes_struct *route)
 153 {
 154         ax25_route *s, *t, *ax25_rt;
 155         ax25_dev *ax25_dev;
 156
 157         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
 158                 return -EINVAL;
 159
 160         write_lock_bh(&ax25_route_lock);
 161
 162         ax25_rt = ax25_route_list;
 163         while (ax25_rt != NULL) {
 164                 s       = ax25_rt;
 165                 ax25_rt = ax25_rt->next;
 166                 if (s->dev == ax25_dev->dev &&
 167                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
 168                         if (ax25_route_list == s) {
 169                                 ax25_route_list = s->next;
 170                                 ax25_put_route(s);
 171                         } else {
 172                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 173                                         if (t->next == s) {
 174                                                 t->next = s->next;
 175                                                 ax25_put_route(s);
 176                                                 break;
 177                                         }
 178                                 }
 179                         }
 180                 }
 181         }
 182         write_unlock_bh(&ax25_route_lock);
 183         ax25_dev_put(ax25_dev);
 184
 185         return 0;
 186 }
 187
 188 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
 189 {
 190         ax25_route *ax25_rt;
 191         ax25_dev *ax25_dev;
 192         int err = 0;
 193
 194         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
 195                 return -EINVAL;
 196
 197         write_lock_bh(&ax25_route_lock);
 198
 199         ax25_rt = ax25_route_list;
 200         while (ax25_rt != NULL) {
 201                 if (ax25_rt->dev == ax25_dev->dev &&
 202                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
 203                         switch (rt_option->cmd) {
 204                         case AX25_SET_RT_IPMODE:
 205                                 switch (rt_option->arg) {
 206                                 case ' ':
 207                                 case 'D':
 208                                 case 'V':
 209                                         ax25_rt->ip_mode = rt_option->arg;
 210                                         break;
 211                                 default:
 212                                         err = -EINVAL;
 213                                         goto out;
 214                                 }
 215                                 break;
 216                         default:
 217                                 err = -EINVAL;
 218                                 goto out;
 219                         }
 220                 }
 221                 ax25_rt = ax25_rt->next;
 222         }
 223
 224 out:
 225         write_unlock_bh(&ax25_route_lock);
 226         ax25_dev_put(ax25_dev);
 227         return err;
 228 }
 229
 230 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
 231 {
 232         struct ax25_route_opt_struct rt_option;
 233         struct ax25_routes_struct route;
 234
 235         switch (cmd) {
 236         case SIOCADDRT:
 237                 if (copy_from_user(&route, arg, sizeof(route)))
 238                         return -EFAULT;
 239                 return ax25_rt_add(&route);
 240
 241         case SIOCDELRT:
 242                 if (copy_from_user(&route, arg, sizeof(route)))
 243                         return -EFAULT;
 244                 return ax25_rt_del(&route);
 245
 246         case SIOCAX25OPTRT:
 247                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 248                         return -EFAULT;
 249                 return ax25_rt_opt(&rt_option);
 250
 251         default:
 252                 return -EINVAL;
 253         }
 254 }
 255
 256 #ifdef CONFIG_PROC_FS
 257
 258 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
 259         __acquires(ax25_route_lock)
 260 {
 261         struct ax25_route *ax25_rt;
 262         int i = 1;
 263
 264         read_lock(&ax25_route_lock);
 265         if (*pos == 0)
 266                 return SEQ_START_TOKEN;
 267
 268         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 269                 if (i == *pos)
 270                         return ax25_rt;
 271                 ++i;
 272         }
 273
 274         return NULL;
 275 }
 276
 277 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 278 {
 279         ++*pos;
 280         return (v == SEQ_START_TOKEN) ? ax25_route_list :
 281                 ((struct ax25_route *) v)->next;
 282 }
 283
 284 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
 285         __releases(ax25_route_lock)
 286 {
 287         read_unlock(&ax25_route_lock);
 288 }
 289
 290 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
 291 {
 292         char buf[11];
 293
 294         if (v == SEQ_START_TOKEN)
 295                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 296         else {
 297                 struct ax25_route *ax25_rt = v;
 298                 const char *callsign;
 299                 int i;
 300
 301                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 302                         callsign = "default";
 303                 else
 304                         callsign = ax2asc(buf, &ax25_rt->callsign);
 305
 306                 seq_printf(seq, "%-9s %-4s",
 307                         callsign,
 308                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 309
 310                 switch (ax25_rt->ip_mode) {
 311                 case 'V':
 312                         seq_puts(seq, "   vc");
 313                         break;
 314                 case 'D':
 315                         seq_puts(seq, "   dg");
 316                         break;
 317                 default:
 318                         seq_puts(seq, "    *");
 319                         break;
 320                 }
 321
 322                 if (ax25_rt->digipeat != NULL)
 323                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 324                                 seq_printf(seq, " %s",
 325                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
 326
 327                 seq_puts(seq, "\n");
 328         }
 329         return 0;
 330 }
 331
 332 const struct seq_operations ax25_rt_seqops = {
 333         .start = ax25_rt_seq_start,
 334         .next = ax25_rt_seq_next,
 335         .stop = ax25_rt_seq_stop,
 336         .show = ax25_rt_seq_show,
 337 };
 338 #endif
 339
 340 /*
 341  *      Find AX.25 route
 342  *
 343  *      Only routes with a reference count of zero can be destroyed.
 344  *      Must be called with ax25_route_lock read locked.
 345  */
 346 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 347 {
 348         ax25_route *ax25_spe_rt = NULL;
 349         ax25_route *ax25_def_rt = NULL;
 350         ax25_route *ax25_rt;
 351
 352         /*
 353          *      Bind to the physical interface we heard them on, or the default
 354          *      route if none is found;
 355          */
 356         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 357                 if (dev == NULL) {
 358                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 359                                 ax25_spe_rt = ax25_rt;
 360                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 361                                 ax25_def_rt = ax25_rt;
 362                 } else {
 363                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 364                                 ax25_spe_rt = ax25_rt;
 365                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 366                                 ax25_def_rt = ax25_rt;
 367                 }
 368         }
 369
 370         ax25_rt = ax25_def_rt;
 371         if (ax25_spe_rt != NULL)
 372                 ax25_rt = ax25_spe_rt;
 373
 374         return ax25_rt;
 375 }
 376
 377 /*
 378  *      Adjust path: If you specify a default route and want to connect
 379  *      a target on the digipeater path but w/o having a special route
 380  *      set before, the path has to be truncated from your target on.
 381  */
 382 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 383 {
 384         int k;
 385
 386         for (k = 0; k < digipeat->ndigi; k++) {
 387                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 388                         break;
 389         }
 390
 391         digipeat->ndigi = k;
 392 }
 393
 394
 395 /*
 396  *      Find which interface to use.
 397  */
 398 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 399 {
 400         ax25_uid_assoc *user;
 401         ax25_route *ax25_rt;
 402         int err = 0;
 403
 404         ax25_route_lock_use();
 405         ax25_rt = ax25_get_route(addr, NULL);
 406         if (!ax25_rt) {
 407                 ax25_route_lock_unuse();
 408                 return -EHOSTUNREACH;
 409         }
 410         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 411                 err = -EHOSTUNREACH;
 412                 goto put;
 413         }
 414
 415         user = ax25_findbyuid(current_euid());
 416         if (user) {
 417                 ax25->source_addr = user->call;
 418                 ax25_uid_put(user);
 419         } else {
 420                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 421                         err = -EPERM;
 422                         goto put;
 423                 }
 424                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
 425         }
 426
 427         if (ax25_rt->digipeat != NULL) {
 428                 ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
 429                                          GFP_ATOMIC);
 430                 if (ax25->digipeat == NULL) {
 431                         err = -ENOMEM;
 432                         goto put;
 433                 }
 434                 ax25_adjust_path(addr, ax25->digipeat);
 435         }
 436
 437         if (ax25->sk != NULL) {
 438                 local_bh_disable();
 439                 bh_lock_sock(ax25->sk);
 440                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 441                 bh_unlock_sock(ax25->sk);
 442                 local_bh_enable();
 443         }
 444
 445 put:
 446         ax25_route_lock_unuse();
 447         return err;
 448 }
 449
 450 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 451         ax25_address *dest, ax25_digi *digi)
 452 {
 453         unsigned char *bp;
 454         int len;
 455
 456         len = digi->ndigi * AX25_ADDR_LEN;
 457
 458         if (unlikely(skb_headroom(skb) < len)) {
 459                 skb = skb_expand_head(skb, len);
 460                 if (!skb) {
 461                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 462                         return NULL;
 463                 }
 464         }
 465
 466         bp = skb_push(skb, len);
 467
 468         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 469
 470         return skb;
 471 }
 472
 473 /*
 474  *      Free all memory associated with routing structures.
 475  */
 476 void __exit ax25_rt_free(void)
 477 {
 478         ax25_route *s, *ax25_rt = ax25_route_list;
 479
 480         write_lock_bh(&ax25_route_lock);
 481         while (ax25_rt != NULL) {
 482                 s       = ax25_rt;
 483                 ax25_rt = ax25_rt->next;
 484
 485                 kfree(s->digipeat);
 486                 kfree(s);
 487         }
 488         write_unlock_bh(&ax25_route_lock);
 489 }