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 <asm/uaccess.h>
  35 #include <asm/system.h>
  36 #include <linux/fcntl.h>
  37 #include <linux/mm.h>
  38 #include <linux/interrupt.h>
  39 #include <linux/init.h>
  40 #include <linux/seq_file.h>
  41 #include <linux/export.h>
  42
  43 static ax25_route *ax25_route_list;
  44 static DEFINE_RWLOCK(ax25_route_lock);
  45
  46 void ax25_rt_device_down(struct net_device *dev)
  47 {
  48         ax25_route *s, *t, *ax25_rt;
  49
  50         write_lock_bh(&ax25_route_lock);
  51         ax25_rt = ax25_route_list;
  52         while (ax25_rt != NULL) {
  53                 s       = ax25_rt;
  54                 ax25_rt = ax25_rt->next;
  55
  56                 if (s->dev == dev) {
  57                         if (ax25_route_list == s) {
  58                                 ax25_route_list = s->next;
  59                                 kfree(s->digipeat);
  60                                 kfree(s);
  61                         } else {
  62                                 for (t = ax25_route_list; t != NULL; t = t->next) {
  63                                         if (t->next == s) {
  64                                                 t->next = s->next;
  65                                                 kfree(s->digipeat);
  66                                                 kfree(s);
  67                                                 break;
  68                                         }
  69                                 }
  70                         }
  71                 }
  72         }
  73         write_unlock_bh(&ax25_route_lock);
  74 }
  75
  76 static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
  77 {
  78         ax25_route *ax25_rt;
  79         ax25_dev *ax25_dev;
  80         int i;
  81
  82         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
  83                 return -EINVAL;
  84         if (route->digi_count > AX25_MAX_DIGIS)
  85                 return -EINVAL;
  86
  87         write_lock_bh(&ax25_route_lock);
  88
  89         ax25_rt = ax25_route_list;
  90         while (ax25_rt != NULL) {
  91                 if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
  92                             ax25_rt->dev == ax25_dev->dev) {
  93                         kfree(ax25_rt->digipeat);
  94                         ax25_rt->digipeat = NULL;
  95                         if (route->digi_count != 0) {
  96                                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
  97                                         write_unlock_bh(&ax25_route_lock);
  98                                         return -ENOMEM;
  99                                 }
 100                                 ax25_rt->digipeat->lastrepeat = -1;
 101                                 ax25_rt->digipeat->ndigi      = route->digi_count;
 102                                 for (i = 0; i < route->digi_count; i++) {
 103                                         ax25_rt->digipeat->repeated[i] = 0;
 104                                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 105                                 }
 106                         }
 107                         write_unlock_bh(&ax25_route_lock);
 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                 return -ENOMEM;
 116         }
 117
 118         atomic_set(&ax25_rt->refcount, 1);
 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                         return -ENOMEM;
 128                 }
 129                 ax25_rt->digipeat->lastrepeat = -1;
 130                 ax25_rt->digipeat->ndigi      = route->digi_count;
 131                 for (i = 0; i < route->digi_count; i++) {
 132                         ax25_rt->digipeat->repeated[i] = 0;
 133                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 134                 }
 135         }
 136         ax25_rt->next   = ax25_route_list;
 137         ax25_route_list = ax25_rt;
 138         write_unlock_bh(&ax25_route_lock);
 139
 140         return 0;
 141 }
 142
 143 void __ax25_put_route(ax25_route *ax25_rt)
 144 {
 145         kfree(ax25_rt->digipeat);
 146         kfree(ax25_rt);
 147 }
 148
 149 static int ax25_rt_del(struct ax25_routes_struct *route)
 150 {
 151         ax25_route *s, *t, *ax25_rt;
 152         ax25_dev *ax25_dev;
 153
 154         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
 155                 return -EINVAL;
 156
 157         write_lock_bh(&ax25_route_lock);
 158
 159         ax25_rt = ax25_route_list;
 160         while (ax25_rt != NULL) {
 161                 s       = ax25_rt;
 162                 ax25_rt = ax25_rt->next;
 163                 if (s->dev == ax25_dev->dev &&
 164                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
 165                         if (ax25_route_list == s) {
 166                                 ax25_route_list = s->next;
 167                                 ax25_put_route(s);
 168                         } else {
 169                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 170                                         if (t->next == s) {
 171                                                 t->next = s->next;
 172                                                 ax25_put_route(s);
 173                                                 break;
 174                                         }
 175                                 }
 176                         }
 177                 }
 178         }
 179         write_unlock_bh(&ax25_route_lock);
 180
 181         return 0;
 182 }
 183
 184 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
 185 {
 186         ax25_route *ax25_rt;
 187         ax25_dev *ax25_dev;
 188         int err = 0;
 189
 190         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
 191                 return -EINVAL;
 192
 193         write_lock_bh(&ax25_route_lock);
 194
 195         ax25_rt = ax25_route_list;
 196         while (ax25_rt != NULL) {
 197                 if (ax25_rt->dev == ax25_dev->dev &&
 198                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
 199                         switch (rt_option->cmd) {
 200                         case AX25_SET_RT_IPMODE:
 201                                 switch (rt_option->arg) {
 202                                 case ' ':
 203                                 case 'D':
 204                                 case 'V':
 205                                         ax25_rt->ip_mode = rt_option->arg;
 206                                         break;
 207                                 default:
 208                                         err = -EINVAL;
 209                                         goto out;
 210                                 }
 211                                 break;
 212                         default:
 213                                 err = -EINVAL;
 214                                 goto out;
 215                         }
 216                 }
 217                 ax25_rt = ax25_rt->next;
 218         }
 219
 220 out:
 221         write_unlock_bh(&ax25_route_lock);
 222         return err;
 223 }
 224
 225 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
 226 {
 227         struct ax25_route_opt_struct rt_option;
 228         struct ax25_routes_struct route;
 229
 230         switch (cmd) {
 231         case SIOCADDRT:
 232                 if (copy_from_user(&route, arg, sizeof(route)))
 233                         return -EFAULT;
 234                 return ax25_rt_add(&route);
 235
 236         case SIOCDELRT:
 237                 if (copy_from_user(&route, arg, sizeof(route)))
 238                         return -EFAULT;
 239                 return ax25_rt_del(&route);
 240
 241         case SIOCAX25OPTRT:
 242                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 243                         return -EFAULT;
 244                 return ax25_rt_opt(&rt_option);
 245
 246         default:
 247                 return -EINVAL;
 248         }
 249 }
 250
 251 #ifdef CONFIG_PROC_FS
 252
 253 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
 254         __acquires(ax25_route_lock)
 255 {
 256         struct ax25_route *ax25_rt;
 257         int i = 1;
 258
 259         read_lock(&ax25_route_lock);
 260         if (*pos == 0)
 261                 return SEQ_START_TOKEN;
 262
 263         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 264                 if (i == *pos)
 265                         return ax25_rt;
 266                 ++i;
 267         }
 268
 269         return NULL;
 270 }
 271
 272 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 273 {
 274         ++*pos;
 275         return (v == SEQ_START_TOKEN) ? ax25_route_list :
 276                 ((struct ax25_route *) v)->next;
 277 }
 278
 279 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
 280         __releases(ax25_route_lock)
 281 {
 282         read_unlock(&ax25_route_lock);
 283 }
 284
 285 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
 286 {
 287         char buf[11];
 288
 289         if (v == SEQ_START_TOKEN)
 290                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 291         else {
 292                 struct ax25_route *ax25_rt = v;
 293                 const char *callsign;
 294                 int i;
 295
 296                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 297                         callsign = "default";
 298                 else
 299                         callsign = ax2asc(buf, &ax25_rt->callsign);
 300
 301                 seq_printf(seq, "%-9s %-4s",
 302                         callsign,
 303                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 304
 305                 switch (ax25_rt->ip_mode) {
 306                 case 'V':
 307                         seq_puts(seq, "   vc");
 308                         break;
 309                 case 'D':
 310                         seq_puts(seq, "   dg");
 311                         break;
 312                 default:
 313                         seq_puts(seq, "    *");
 314                         break;
 315                 }
 316
 317                 if (ax25_rt->digipeat != NULL)
 318                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 319                                 seq_printf(seq, " %s",
 320                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
 321
 322                 seq_puts(seq, "\n");
 323         }
 324         return 0;
 325 }
 326
 327 static const struct seq_operations ax25_rt_seqops = {
 328         .start = ax25_rt_seq_start,
 329         .next = ax25_rt_seq_next,
 330         .stop = ax25_rt_seq_stop,
 331         .show = ax25_rt_seq_show,
 332 };
 333
 334 static int ax25_rt_info_open(struct inode *inode, struct file *file)
 335 {
 336         return seq_open(file, &ax25_rt_seqops);
 337 }
 338
 339 const struct file_operations ax25_route_fops = {
 340         .owner = THIS_MODULE,
 341         .open = ax25_rt_info_open,
 342         .read = seq_read,
 343         .llseek = seq_lseek,
 344         .release = seq_release,
 345 };
 346
 347 #endif
 348
 349 /*
 350  *      Find AX.25 route
 351  *
 352  *      Only routes with a reference count of zero can be destroyed.
 353  */
 354 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 355 {
 356         ax25_route *ax25_spe_rt = NULL;
 357         ax25_route *ax25_def_rt = NULL;
 358         ax25_route *ax25_rt;
 359
 360         read_lock(&ax25_route_lock);
 361         /*
 362          *      Bind to the physical interface we heard them on, or the default
 363          *      route if none is found;
 364          */
 365         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 366                 if (dev == NULL) {
 367                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 368                                 ax25_spe_rt = ax25_rt;
 369                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 370                                 ax25_def_rt = ax25_rt;
 371                 } else {
 372                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 373                                 ax25_spe_rt = ax25_rt;
 374                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 375                                 ax25_def_rt = ax25_rt;
 376                 }
 377         }
 378
 379         ax25_rt = ax25_def_rt;
 380         if (ax25_spe_rt != NULL)
 381                 ax25_rt = ax25_spe_rt;
 382
 383         if (ax25_rt != NULL)
 384                 ax25_hold_route(ax25_rt);
 385
 386         read_unlock(&ax25_route_lock);
 387
 388         return ax25_rt;
 389 }
 390
 391 /*
 392  *      Adjust path: If you specify a default route and want to connect
 393  *      a target on the digipeater path but w/o having a special route
 394  *      set before, the path has to be truncated from your target on.
 395  */
 396 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 397 {
 398         int k;
 399
 400         for (k = 0; k < digipeat->ndigi; k++) {
 401                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 402                         break;
 403         }
 404
 405         digipeat->ndigi = k;
 406 }
 407
 408
 409 /*
 410  *      Find which interface to use.
 411  */
 412 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 413 {
 414         ax25_uid_assoc *user;
 415         ax25_route *ax25_rt;
 416         int err = 0;
 417
 418         if ((ax25_rt = ax25_get_route(addr, NULL)) == NULL)
 419                 return -EHOSTUNREACH;
 420
 421         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 422                 err = -EHOSTUNREACH;
 423                 goto put;
 424         }
 425
 426         user = ax25_findbyuid(current_euid());
 427         if (user) {
 428                 ax25->source_addr = user->call;
 429                 ax25_uid_put(user);
 430         } else {
 431                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 432                         err = -EPERM;
 433                         goto put;
 434                 }
 435                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
 436         }
 437
 438         if (ax25_rt->digipeat != NULL) {
 439                 ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
 440                                          GFP_ATOMIC);
 441                 if (ax25->digipeat == NULL) {
 442                         err = -ENOMEM;
 443                         goto put;
 444                 }
 445                 ax25_adjust_path(addr, ax25->digipeat);
 446         }
 447
 448         if (ax25->sk != NULL) {
 449                 bh_lock_sock(ax25->sk);
 450                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 451                 bh_unlock_sock(ax25->sk);
 452         }
 453
 454 put:
 455         ax25_put_route(ax25_rt);
 456
 457         return err;
 458 }
 459
 460 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 461         ax25_address *dest, ax25_digi *digi)
 462 {
 463         struct sk_buff *skbn;
 464         unsigned char *bp;
 465         int len;
 466
 467         len = digi->ndigi * AX25_ADDR_LEN;
 468
 469         if (skb_headroom(skb) < len) {
 470                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
 471                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 472                         return NULL;
 473                 }
 474
 475                 if (skb->sk != NULL)
 476                         skb_set_owner_w(skbn, skb->sk);
 477
 478                 kfree_skb(skb);
 479
 480                 skb = skbn;
 481         }
 482
 483         bp = skb_push(skb, len);
 484
 485         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 486
 487         return skb;
 488 }
 489
 490 /*
 491  *      Free all memory associated with routing structures.
 492  */
 493 void __exit ax25_rt_free(void)
 494 {
 495         ax25_route *s, *ax25_rt = ax25_route_list;
 496
 497         write_lock_bh(&ax25_route_lock);
 498         while (ax25_rt != NULL) {
 499                 s       = ax25_rt;
 500                 ax25_rt = ax25_rt->next;
 501
 502                 kfree(s->digipeat);
 503                 kfree(s);
 504         }
 505         write_unlock_bh(&ax25_route_lock);
 506 }