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 <net/ax25.h>
  27 #include <linux/inet.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/if_arp.h>
  30 #include <linux/skbuff.h>
  31 #include <linux/spinlock.h>
  32 #include <net/sock.h>
  33 #include <asm/uaccess.h>
  34 #include <asm/system.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
  41 static ax25_route *ax25_route_list;
  42 static DEFINE_RWLOCK(ax25_route_lock);
  43
  44 static ax25_route *ax25_get_route(ax25_address *, struct net_device *);
  45
  46 void ax25_rt_device_down(struct net_device *dev)
  47 {
  48         ax25_route *s, *t, *ax25_rt;
  49
  50         write_lock(&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(&ax25_route_lock);
  74 }
  75
  76 static int 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(&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(&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(&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(&ax25_route_lock);
 115                 return -ENOMEM;
 116         }
 117
 118         atomic_set(&ax25_rt->ref, 0);
 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(&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(&ax25_route_lock);
 139
 140         return 0;
 141 }
 142
 143 static void ax25_rt_destroy(ax25_route *ax25_rt)
 144 {
 145         if (atomic_read(&ax25_rt->ref) == 0) {
 146                 kfree(ax25_rt->digipeat);
 147                 kfree(ax25_rt);
 148                 return;
 149         }
 150
 151         /*
 152          * Uh...  Route is still in use; we can't yet destroy it.  Retry later.
 153          */
 154         init_timer(&ax25_rt->timer);
 155         ax25_rt->timer.data     = (unsigned long) ax25_rt;
 156         ax25_rt->timer.function = (void *) ax25_rt_destroy;
 157         ax25_rt->timer.expires  = jiffies + 5 * HZ;
 158
 159         add_timer(&ax25_rt->timer);
 160 }
 161
 162 static int ax25_rt_del(struct ax25_routes_struct *route)
 163 {
 164         ax25_route *s, *t, *ax25_rt;
 165         ax25_dev *ax25_dev;
 166
 167         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
 168                 return -EINVAL;
 169
 170         write_lock(&ax25_route_lock);
 171
 172         ax25_rt = ax25_route_list;
 173         while (ax25_rt != NULL) {
 174                 s       = ax25_rt;
 175                 ax25_rt = ax25_rt->next;
 176                 if (s->dev == ax25_dev->dev &&
 177                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
 178                         if (ax25_route_list == s) {
 179                                 ax25_route_list = s->next;
 180                                 ax25_rt_destroy(s);
 181                         } else {
 182                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 183                                         if (t->next == s) {
 184                                                 t->next = s->next;
 185                                                 ax25_rt_destroy(s);
 186                                                 break;
 187                                         }
 188                                 }
 189                         }
 190                 }
 191         }
 192         write_unlock(&ax25_route_lock);
 193
 194         return 0;
 195 }
 196
 197 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
 198 {
 199         ax25_route *ax25_rt;
 200         ax25_dev *ax25_dev;
 201         int err = 0;
 202
 203         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
 204                 return -EINVAL;
 205
 206         write_lock(&ax25_route_lock);
 207
 208         ax25_rt = ax25_route_list;
 209         while (ax25_rt != NULL) {
 210                 if (ax25_rt->dev == ax25_dev->dev &&
 211                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
 212                         switch (rt_option->cmd) {
 213                         case AX25_SET_RT_IPMODE:
 214                                 switch (rt_option->arg) {
 215                                 case ' ':
 216                                 case 'D':
 217                                 case 'V':
 218                                         ax25_rt->ip_mode = rt_option->arg;
 219                                         break;
 220                                 default:
 221                                         err = -EINVAL;
 222                                         goto out;
 223                                 }
 224                                 break;
 225                         default:
 226                                 err = -EINVAL;
 227                                 goto out;
 228                         }
 229                 }
 230                 ax25_rt = ax25_rt->next;
 231         }
 232
 233 out:
 234         write_unlock(&ax25_route_lock);
 235         return err;
 236 }
 237
 238 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
 239 {
 240         struct ax25_route_opt_struct rt_option;
 241         struct ax25_routes_struct route;
 242
 243         switch (cmd) {
 244         case SIOCADDRT:
 245                 if (copy_from_user(&route, arg, sizeof(route)))
 246                         return -EFAULT;
 247                 return ax25_rt_add(&route);
 248
 249         case SIOCDELRT:
 250                 if (copy_from_user(&route, arg, sizeof(route)))
 251                         return -EFAULT;
 252                 return ax25_rt_del(&route);
 253
 254         case SIOCAX25OPTRT:
 255                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 256                         return -EFAULT;
 257                 return ax25_rt_opt(&rt_option);
 258
 259         default:
 260                 return -EINVAL;
 261         }
 262 }
 263
 264 #ifdef CONFIG_PROC_FS
 265
 266 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
 267 {
 268         struct ax25_route *ax25_rt;
 269         int i = 1;
 270
 271         read_lock(&ax25_route_lock);
 272         if (*pos == 0)
 273                 return SEQ_START_TOKEN;
 274
 275         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 276                 if (i == *pos)
 277                         return ax25_rt;
 278                 ++i;
 279         }
 280
 281         return NULL;
 282 }
 283
 284 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 285 {
 286         ++*pos;
 287         return (v == SEQ_START_TOKEN) ? ax25_route_list :
 288                 ((struct ax25_route *) v)->next;
 289 }
 290
 291 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
 292 {
 293         read_unlock(&ax25_route_lock);
 294 }
 295
 296 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
 297 {
 298         char buf[11];
 299
 300         if (v == SEQ_START_TOKEN)
 301                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 302         else {
 303                 struct ax25_route *ax25_rt = v;
 304                 const char *callsign;
 305                 int i;
 306
 307                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 308                         callsign = "default";
 309                 else
 310                         callsign = ax2asc(buf, &ax25_rt->callsign);
 311
 312                 seq_printf(seq, "%-9s %-4s",
 313                         callsign,
 314                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 315
 316                 switch (ax25_rt->ip_mode) {
 317                 case 'V':
 318                         seq_puts(seq, "   vc");
 319                         break;
 320                 case 'D':
 321                         seq_puts(seq, "   dg");
 322                         break;
 323                 default:
 324                         seq_puts(seq, "    *");
 325                         break;
 326                 }
 327
 328                 if (ax25_rt->digipeat != NULL)
 329                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 330                                 seq_printf(seq, " %s",
 331                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
 332
 333                 seq_puts(seq, "\n");
 334         }
 335         return 0;
 336 }
 337
 338 static struct seq_operations ax25_rt_seqops = {
 339         .start = ax25_rt_seq_start,
 340         .next = ax25_rt_seq_next,
 341         .stop = ax25_rt_seq_stop,
 342         .show = ax25_rt_seq_show,
 343 };
 344
 345 static int ax25_rt_info_open(struct inode *inode, struct file *file)
 346 {
 347         return seq_open(file, &ax25_rt_seqops);
 348 }
 349
 350 struct file_operations ax25_route_fops = {
 351         .owner = THIS_MODULE,
 352         .open = ax25_rt_info_open,
 353         .read = seq_read,
 354         .llseek = seq_lseek,
 355         .release = seq_release,
 356 };
 357
 358 #endif
 359
 360 /*
 361  *      Find AX.25 route
 362  *
 363  *      Only routes with a reference count of zero can be destroyed.
 364  */
 365 static ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 366 {
 367         ax25_route *ax25_spe_rt = NULL;
 368         ax25_route *ax25_def_rt = NULL;
 369         ax25_route *ax25_rt;
 370
 371         read_lock(&ax25_route_lock);
 372         /*
 373          *      Bind to the physical interface we heard them on, or the default
 374          *      route if none is found;
 375          */
 376         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 377                 if (dev == NULL) {
 378                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 379                                 ax25_spe_rt = ax25_rt;
 380                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 381                                 ax25_def_rt = ax25_rt;
 382                 } else {
 383                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 384                                 ax25_spe_rt = ax25_rt;
 385                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 386                                 ax25_def_rt = ax25_rt;
 387                 }
 388         }
 389
 390         ax25_rt = ax25_def_rt;
 391         if (ax25_spe_rt != NULL)
 392                 ax25_rt = ax25_spe_rt;
 393
 394         if (ax25_rt != NULL)
 395                 atomic_inc(&ax25_rt->ref);
 396
 397         read_unlock(&ax25_route_lock);
 398
 399         return ax25_rt;
 400 }
 401
 402 /*
 403  *      Adjust path: If you specify a default route and want to connect
 404  *      a target on the digipeater path but w/o having a special route
 405  *      set before, the path has to be truncated from your target on.
 406  */
 407 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 408 {
 409         int k;
 410
 411         for (k = 0; k < digipeat->ndigi; k++) {
 412                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 413                         break;
 414         }
 415
 416         digipeat->ndigi = k;
 417 }
 418
 419
 420 /*
 421  *      Find which interface to use.
 422  */
 423 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 424 {
 425         ax25_uid_assoc *user;
 426         ax25_route *ax25_rt;
 427         int err;
 428
 429         if ((ax25_rt = ax25_get_route(addr, NULL)) == NULL)
 430                 return -EHOSTUNREACH;
 431
 432         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 433                 err = -EHOSTUNREACH;
 434                 goto put;
 435         }
 436
 437         user = ax25_findbyuid(current->euid);
 438         if (user) {
 439                 ax25->source_addr = user->call;
 440                 ax25_uid_put(user);
 441         } else {
 442                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 443                         err = -EPERM;
 444                         goto put;
 445                 }
 446                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
 447         }
 448
 449         if (ax25_rt->digipeat != NULL) {
 450                 if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 451                         err = -ENOMEM;
 452                         goto put;
 453                 }
 454                 memcpy(ax25->digipeat, ax25_rt->digipeat, sizeof(ax25_digi));
 455                 ax25_adjust_path(addr, ax25->digipeat);
 456         }
 457
 458         if (ax25->sk != NULL) {
 459                 bh_lock_sock(ax25->sk);
 460                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 461                 bh_unlock_sock(ax25->sk);
 462         }
 463
 464 put:
 465         ax25_put_route(ax25_rt);
 466
 467         return 0;
 468 }
 469
 470 ax25_route *ax25_rt_find_route(ax25_route * route, ax25_address *addr,
 471         struct net_device *dev)
 472 {
 473         ax25_route *ax25_rt;
 474
 475         if ((ax25_rt = ax25_get_route(addr, dev)))
 476                 return ax25_rt;
 477
 478         route->next     = NULL;
 479         atomic_set(&route->ref, 1);
 480         route->callsign = *addr;
 481         route->dev      = dev;
 482         route->digipeat = NULL;
 483         route->ip_mode  = ' ';
 484
 485         return route;
 486 }
 487
 488 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 489         ax25_address *dest, ax25_digi *digi)
 490 {
 491         struct sk_buff *skbn;
 492         unsigned char *bp;
 493         int len;
 494
 495         len = digi->ndigi * AX25_ADDR_LEN;
 496
 497         if (skb_headroom(skb) < len) {
 498                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
 499                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 500                         return NULL;
 501                 }
 502
 503                 if (skb->sk != NULL)
 504                         skb_set_owner_w(skbn, skb->sk);
 505
 506                 kfree_skb(skb);
 507
 508                 skb = skbn;
 509         }
 510
 511         bp = skb_push(skb, len);
 512
 513         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 514
 515         return skb;
 516 }
 517
 518 /*
 519  *      Free all memory associated with routing structures.
 520  */
 521 void __exit ax25_rt_free(void)
 522 {
 523         ax25_route *s, *ax25_rt = ax25_route_list;
 524
 525         write_lock(&ax25_route_lock);
 526         while (ax25_rt != NULL) {
 527                 s       = ax25_rt;
 528                 ax25_rt = ax25_rt->next;
 529
 530                 kfree(s->digipeat);
 531                 kfree(s);
 532         }
 533         write_unlock(&ax25_route_lock);
 534 }