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         if (v == SEQ_START_TOKEN)
 302                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 303         else {
 304                 struct ax25_route *ax25_rt = v;
 305                 const char *callsign;
 306                 int i;
 307
 308                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 309                         callsign = "default";
 310                 else
 311                         callsign = ax2asc(&ax25_rt->callsign);
 312
 313                 seq_printf(seq, "%-9s %-4s",
 314                         callsign,
 315                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 316
 317                 switch (ax25_rt->ip_mode) {
 318                 case 'V':
 319                         seq_puts(seq, "   vc");
 320                         break;
 321                 case 'D':
 322                         seq_puts(seq, "   dg");
 323                         break;
 324                 default:
 325                         seq_puts(seq, "    *");
 326                         break;
 327                 }
 328
 329                 if (ax25_rt->digipeat != NULL)
 330                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 331                                 seq_printf(seq, " %s", ax2asc(&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 refernce rout 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_route *ax25_rt;
 426         ax25_address *call;
 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         if ((call = ax25_findbyuid(current->euid)) == NULL) {
 438                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 439                         err = -EPERM;
 440                         goto put;
 441                 }
 442                 call = (ax25_address *)ax25->ax25_dev->dev->dev_addr;
 443         }
 444
 445         ax25->source_addr = *call;
 446
 447         if (ax25_rt->digipeat != NULL) {
 448                 if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 449                         err = -ENOMEM;
 450                         goto put;
 451                 }
 452                 memcpy(ax25->digipeat, ax25_rt->digipeat, sizeof(ax25_digi));
 453                 ax25_adjust_path(addr, ax25->digipeat);
 454         }
 455
 456         if (ax25->sk != NULL) {
 457                 bh_lock_sock(ax25->sk);
 458                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 459                 bh_unlock_sock(ax25->sk);
 460         }
 461
 462 put:
 463         ax25_put_route(ax25_rt);
 464
 465         return 0;
 466 }
 467
 468 ax25_route *ax25_rt_find_route(ax25_route * route, ax25_address *addr,
 469         struct net_device *dev)
 470 {
 471         ax25_route *ax25_rt;
 472
 473         if ((ax25_rt = ax25_get_route(addr, dev)))
 474                 return ax25_rt;
 475
 476         route->next     = NULL;
 477         atomic_set(&route->ref, 1);
 478         route->callsign = *addr;
 479         route->dev      = dev;
 480         route->digipeat = NULL;
 481         route->ip_mode  = ' ';
 482
 483         return route;
 484 }
 485
 486 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 487         ax25_address *dest, ax25_digi *digi)
 488 {
 489         struct sk_buff *skbn;
 490         unsigned char *bp;
 491         int len;
 492
 493         len = digi->ndigi * AX25_ADDR_LEN;
 494
 495         if (skb_headroom(skb) < len) {
 496                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
 497                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 498                         return NULL;
 499                 }
 500
 501                 if (skb->sk != NULL)
 502                         skb_set_owner_w(skbn, skb->sk);
 503
 504                 kfree_skb(skb);
 505
 506                 skb = skbn;
 507         }
 508
 509         bp = skb_push(skb, len);
 510
 511         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 512
 513         return skb;
 514 }
 515
 516 /*
 517  *      Free all memory associated with routing structures.
 518  */
 519 void __exit ax25_rt_free(void)
 520 {
 521         ax25_route *s, *ax25_rt = ax25_route_list;
 522
 523         write_lock(&ax25_route_lock);
 524         while (ax25_rt != NULL) {
 525                 s       = ax25_rt;
 526                 ax25_rt = ax25_rt->next;
 527
 528                 if (s->digipeat != NULL)
 529                         kfree(s->digipeat);
 530
 531                 kfree(s);
 532         }
 533         write_unlock(&ax25_route_lock);
 534 }