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 #include <linux/errno.h>
  15 #include <linux/types.h>
  16 #include <linux/socket.h>
  17 #include <linux/timer.h>
  18 #include <linux/in.h>
  19 #include <linux/kernel.h>
  20 #include <linux/sched.h>
  21 #include <linux/string.h>
  22 #include <linux/sockios.h>
  23 #include <linux/net.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 <asm/uaccess.h>
  32 #include <asm/system.h>
  33 #include <linux/fcntl.h>
  34 #include <linux/mm.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/init.h>
  37 #include <linux/seq_file.h>
  38
  39 static ax25_route *ax25_route_list;
  40 static DEFINE_RWLOCK(ax25_route_lock);
  41
  42 static ax25_route *ax25_get_route(ax25_address *, struct net_device *);
  43
  44 void ax25_rt_device_down(struct net_device *dev)
  45 {
  46         ax25_route *s, *t, *ax25_rt;
  47
  48         write_lock(&ax25_route_lock);
  49         ax25_rt = ax25_route_list;
  50         while (ax25_rt != NULL) {
  51                 s       = ax25_rt;
  52                 ax25_rt = ax25_rt->next;
  53
  54                 if (s->dev == dev) {
  55                         if (ax25_route_list == s) {
  56                                 ax25_route_list = s->next;
  57                                 if (s->digipeat != NULL)
  58                                         kfree(s->digipeat);
  59                                 kfree(s);
  60                         } else {
  61                                 for (t = ax25_route_list; t != NULL; t = t->next) {
  62                                         if (t->next == s) {
  63                                                 t->next = s->next;
  64                                                 if (s->digipeat != NULL)
  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                         if (ax25_rt->digipeat != NULL) {
  94                                 kfree(ax25_rt->digipeat);
  95                                 ax25_rt->digipeat = NULL;
  96                         }
  97                         if (route->digi_count != 0) {
  98                                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
  99                                         write_unlock(&ax25_route_lock);
 100                                         return -ENOMEM;
 101                                 }
 102                                 ax25_rt->digipeat->lastrepeat = -1;
 103                                 ax25_rt->digipeat->ndigi      = route->digi_count;
 104                                 for (i = 0; i < route->digi_count; i++) {
 105                                         ax25_rt->digipeat->repeated[i] = 0;
 106                                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 107                                 }
 108                         }
 109                         write_unlock(&ax25_route_lock);
 110                         return 0;
 111                 }
 112                 ax25_rt = ax25_rt->next;
 113         }
 114
 115         if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
 116                 write_unlock(&ax25_route_lock);
 117                 return -ENOMEM;
 118         }
 119
 120         atomic_set(&ax25_rt->ref, 0);
 121         ax25_rt->callsign     = route->dest_addr;
 122         ax25_rt->dev          = ax25_dev->dev;
 123         ax25_rt->digipeat     = NULL;
 124         ax25_rt->ip_mode      = ' ';
 125         if (route->digi_count != 0) {
 126                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 127                         write_unlock(&ax25_route_lock);
 128                         kfree(ax25_rt);
 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(&ax25_route_lock);
 141
 142         return 0;
 143 }
 144
 145 static void ax25_rt_destroy(ax25_route *ax25_rt)
 146 {
 147         if (atomic_read(&ax25_rt->ref) == 0) {
 148                 if (ax25_rt->digipeat != NULL)
 149                         kfree(ax25_rt->digipeat);
 150                 kfree(ax25_rt);
 151                 return;
 152         }
 153
 154         /*
 155          * Uh...  Route is still in use; we can't yet destroy it.  Retry later.
 156          */
 157         init_timer(&ax25_rt->timer);
 158         ax25_rt->timer.data     = (unsigned long) ax25_rt;
 159         ax25_rt->timer.function = (void *) ax25_rt_destroy;
 160         ax25_rt->timer.expires  = jiffies + 5 * HZ;
 161
 162         add_timer(&ax25_rt->timer);
 163 }
 164
 165 static int ax25_rt_del(struct ax25_routes_struct *route)
 166 {
 167         ax25_route *s, *t, *ax25_rt;
 168         ax25_dev *ax25_dev;
 169
 170         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
 171                 return -EINVAL;
 172
 173         write_lock(&ax25_route_lock);
 174
 175         ax25_rt = ax25_route_list;
 176         while (ax25_rt != NULL) {
 177                 s       = ax25_rt;
 178                 ax25_rt = ax25_rt->next;
 179                 if (s->dev == ax25_dev->dev &&
 180                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
 181                         if (ax25_route_list == s) {
 182                                 ax25_route_list = s->next;
 183                                 ax25_rt_destroy(s);
 184                         } else {
 185                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 186                                         if (t->next == s) {
 187                                                 t->next = s->next;
 188                                                 ax25_rt_destroy(s);
 189                                                 break;
 190                                         }
 191                                 }
 192                         }
 193                 }
 194         }
 195         write_unlock(&ax25_route_lock);
 196
 197         return 0;
 198 }
 199
 200 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
 201 {
 202         ax25_route *ax25_rt;
 203         ax25_dev *ax25_dev;
 204         int err = 0;
 205
 206         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
 207                 return -EINVAL;
 208
 209         write_lock(&ax25_route_lock);
 210
 211         ax25_rt = ax25_route_list;
 212         while (ax25_rt != NULL) {
 213                 if (ax25_rt->dev == ax25_dev->dev &&
 214                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
 215                         switch (rt_option->cmd) {
 216                         case AX25_SET_RT_IPMODE:
 217                                 switch (rt_option->arg) {
 218                                 case ' ':
 219                                 case 'D':
 220                                 case 'V':
 221                                         ax25_rt->ip_mode = rt_option->arg;
 222                                         break;
 223                                 default:
 224                                         err = -EINVAL;
 225                                         goto out;
 226                                 }
 227                                 break;
 228                         default:
 229                                 err = -EINVAL;
 230                                 goto out;
 231                         }
 232                 }
 233                 ax25_rt = ax25_rt->next;
 234         }
 235
 236 out:
 237         write_unlock(&ax25_route_lock);
 238         return err;
 239 }
 240
 241 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
 242 {
 243         struct ax25_route_opt_struct rt_option;
 244         struct ax25_routes_struct route;
 245
 246         switch (cmd) {
 247         case SIOCADDRT:
 248                 if (copy_from_user(&route, arg, sizeof(route)))
 249                         return -EFAULT;
 250                 return ax25_rt_add(&route);
 251
 252         case SIOCDELRT:
 253                 if (copy_from_user(&route, arg, sizeof(route)))
 254                         return -EFAULT;
 255                 return ax25_rt_del(&route);
 256
 257         case SIOCAX25OPTRT:
 258                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 259                         return -EFAULT;
 260                 return ax25_rt_opt(&rt_option);
 261
 262         default:
 263                 return -EINVAL;
 264         }
 265 }
 266
 267 #ifdef CONFIG_PROC_FS
 268
 269 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
 270 {
 271         struct ax25_route *ax25_rt;
 272         int i = 1;
 273
 274         read_lock(&ax25_route_lock);
 275         if (*pos == 0)
 276                 return SEQ_START_TOKEN;
 277
 278         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 279                 if (i == *pos)
 280                         return ax25_rt;
 281                 ++i;
 282         }
 283
 284         return NULL;
 285 }
 286
 287 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 288 {
 289         ++*pos;
 290         return (v == SEQ_START_TOKEN) ? ax25_route_list :
 291                 ((struct ax25_route *) v)->next;
 292 }
 293
 294 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
 295 {
 296         read_unlock(&ax25_route_lock);
 297 }
 298
 299 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
 300 {
 301         char buf[11];
 302
 303         if (v == SEQ_START_TOKEN)
 304                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 305         else {
 306                 struct ax25_route *ax25_rt = v;
 307                 const char *callsign;
 308                 int i;
 309
 310                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 311                         callsign = "default";
 312                 else
 313                         callsign = ax2asc(buf, &ax25_rt->callsign);
 314
 315                 seq_printf(seq, "%-9s %-4s",
 316                         callsign,
 317                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 318
 319                 switch (ax25_rt->ip_mode) {
 320                 case 'V':
 321                         seq_puts(seq, "   vc");
 322                         break;
 323                 case 'D':
 324                         seq_puts(seq, "   dg");
 325                         break;
 326                 default:
 327                         seq_puts(seq, "    *");
 328                         break;
 329                 }
 330
 331                 if (ax25_rt->digipeat != NULL)
 332                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 333                                 seq_printf(seq, " %s",
 334                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
 335
 336                 seq_puts(seq, "\n");
 337         }
 338         return 0;
 339 }
 340
 341 static struct seq_operations ax25_rt_seqops = {
 342         .start = ax25_rt_seq_start,
 343         .next = ax25_rt_seq_next,
 344         .stop = ax25_rt_seq_stop,
 345         .show = ax25_rt_seq_show,
 346 };
 347
 348 static int ax25_rt_info_open(struct inode *inode, struct file *file)
 349 {
 350         return seq_open(file, &ax25_rt_seqops);
 351 }
 352
 353 struct file_operations ax25_route_fops = {
 354         .owner = THIS_MODULE,
 355         .open = ax25_rt_info_open,
 356         .read = seq_read,
 357         .llseek = seq_lseek,
 358         .release = seq_release,
 359 };
 360
 361 #endif
 362
 363 /*
 364  *      Find AX.25 route
 365  *
 366  *      Only routes with a refernce rout of zero can be destroyed.
 367  */
 368 static ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 369 {
 370         ax25_route *ax25_spe_rt = NULL;
 371         ax25_route *ax25_def_rt = NULL;
 372         ax25_route *ax25_rt;
 373
 374         read_lock(&ax25_route_lock);
 375         /*
 376          *      Bind to the physical interface we heard them on, or the default
 377          *      route if none is found;
 378          */
 379         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 380                 if (dev == NULL) {
 381                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 382                                 ax25_spe_rt = ax25_rt;
 383                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 384                                 ax25_def_rt = ax25_rt;
 385                 } else {
 386                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 387                                 ax25_spe_rt = ax25_rt;
 388                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 389                                 ax25_def_rt = ax25_rt;
 390                 }
 391         }
 392
 393         ax25_rt = ax25_def_rt;
 394         if (ax25_spe_rt != NULL)
 395                 ax25_rt = ax25_spe_rt;
 396
 397         if (ax25_rt != NULL)
 398                 atomic_inc(&ax25_rt->ref);
 399
 400         read_unlock(&ax25_route_lock);
 401
 402         return ax25_rt;
 403 }
 404
 405 /*
 406  *      Adjust path: If you specify a default route and want to connect
 407  *      a target on the digipeater path but w/o having a special route
 408  *      set before, the path has to be truncated from your target on.
 409  */
 410 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 411 {
 412         int k;
 413
 414         for (k = 0; k < digipeat->ndigi; k++) {
 415                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 416                         break;
 417         }
 418
 419         digipeat->ndigi = k;
 420 }
 421
 422
 423 /*
 424  *      Find which interface to use.
 425  */
 426 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 427 {
 428         ax25_uid_assoc *user;
 429         ax25_route *ax25_rt;
 430         int err;
 431
 432         if ((ax25_rt = ax25_get_route(addr, NULL)) == NULL)
 433                 return -EHOSTUNREACH;
 434
 435         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 436                 err = -EHOSTUNREACH;
 437                 goto put;
 438         }
 439
 440         user = ax25_findbyuid(current->euid);
 441         if (user) {
 442                 ax25->source_addr = user->call;
 443                 ax25_uid_put(user);
 444         } else {
 445                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 446                         err = -EPERM;
 447                         goto put;
 448                 }
 449                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
 450         }
 451
 452         if (ax25_rt->digipeat != NULL) {
 453                 if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 454                         err = -ENOMEM;
 455                         goto put;
 456                 }
 457                 memcpy(ax25->digipeat, ax25_rt->digipeat, sizeof(ax25_digi));
 458                 ax25_adjust_path(addr, ax25->digipeat);
 459         }
 460
 461         if (ax25->sk != NULL) {
 462                 bh_lock_sock(ax25->sk);
 463                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 464                 bh_unlock_sock(ax25->sk);
 465         }
 466
 467 put:
 468         ax25_put_route(ax25_rt);
 469
 470         return 0;
 471 }
 472
 473 ax25_route *ax25_rt_find_route(ax25_route * route, ax25_address *addr,
 474         struct net_device *dev)
 475 {
 476         ax25_route *ax25_rt;
 477
 478         if ((ax25_rt = ax25_get_route(addr, dev)))
 479                 return ax25_rt;
 480
 481         route->next     = NULL;
 482         atomic_set(&route->ref, 1);
 483         route->callsign = *addr;
 484         route->dev      = dev;
 485         route->digipeat = NULL;
 486         route->ip_mode  = ' ';
 487
 488         return route;
 489 }
 490
 491 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 492         ax25_address *dest, ax25_digi *digi)
 493 {
 494         struct sk_buff *skbn;
 495         unsigned char *bp;
 496         int len;
 497
 498         len = digi->ndigi * AX25_ADDR_LEN;
 499
 500         if (skb_headroom(skb) < len) {
 501                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
 502                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 503                         return NULL;
 504                 }
 505
 506                 if (skb->sk != NULL)
 507                         skb_set_owner_w(skbn, skb->sk);
 508
 509                 kfree_skb(skb);
 510
 511                 skb = skbn;
 512         }
 513
 514         bp = skb_push(skb, len);
 515
 516         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 517
 518         return skb;
 519 }
 520
 521 /*
 522  *      Free all memory associated with routing structures.
 523  */
 524 void __exit ax25_rt_free(void)
 525 {
 526         ax25_route *s, *ax25_rt = ax25_route_list;
 527
 528         write_lock(&ax25_route_lock);
 529         while (ax25_rt != NULL) {
 530                 s       = ax25_rt;
 531                 ax25_rt = ax25_rt->next;
 532
 533                 if (s->digipeat != NULL)
 534                         kfree(s->digipeat);
 535
 536                 kfree(s);
 537         }
 538         write_unlock(&ax25_route_lock);
 539 }