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 void ax25_rt_device_down(struct net_device *dev)
  45 {
  46         ax25_route *s, *t, *ax25_rt;
  47
  48         write_lock_bh(&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                                 kfree(s->digipeat);
  58                                 kfree(s);
  59                         } else {
  60                                 for (t = ax25_route_list; t != NULL; t = t->next) {
  61                                         if (t->next == s) {
  62                                                 t->next = s->next;
  63                                                 kfree(s->digipeat);
  64                                                 kfree(s);
  65                                                 break;
  66                                         }
  67                                 }
  68                         }
  69                 }
  70         }
  71         write_unlock_bh(&ax25_route_lock);
  72 }
  73
  74 static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
  75 {
  76         ax25_route *ax25_rt;
  77         ax25_dev *ax25_dev;
  78         int i;
  79
  80         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
  81                 return -EINVAL;
  82         if (route->digi_count > AX25_MAX_DIGIS)
  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                                         return -ENOMEM;
  97                                 }
  98                                 ax25_rt->digipeat->lastrepeat = -1;
  99                                 ax25_rt->digipeat->ndigi      = route->digi_count;
 100                                 for (i = 0; i < route->digi_count; i++) {
 101                                         ax25_rt->digipeat->repeated[i] = 0;
 102                                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 103                                 }
 104                         }
 105                         write_unlock_bh(&ax25_route_lock);
 106                         return 0;
 107                 }
 108                 ax25_rt = ax25_rt->next;
 109         }
 110
 111         if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
 112                 write_unlock_bh(&ax25_route_lock);
 113                 return -ENOMEM;
 114         }
 115
 116         atomic_set(&ax25_rt->refcount, 1);
 117         ax25_rt->callsign     = route->dest_addr;
 118         ax25_rt->dev          = ax25_dev->dev;
 119         ax25_rt->digipeat     = NULL;
 120         ax25_rt->ip_mode      = ' ';
 121         if (route->digi_count != 0) {
 122                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 123                         write_unlock_bh(&ax25_route_lock);
 124                         kfree(ax25_rt);
 125                         return -ENOMEM;
 126                 }
 127                 ax25_rt->digipeat->lastrepeat = -1;
 128                 ax25_rt->digipeat->ndigi      = route->digi_count;
 129                 for (i = 0; i < route->digi_count; i++) {
 130                         ax25_rt->digipeat->repeated[i] = 0;
 131                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 132                 }
 133         }
 134         ax25_rt->next   = ax25_route_list;
 135         ax25_route_list = ax25_rt;
 136         write_unlock_bh(&ax25_route_lock);
 137
 138         return 0;
 139 }
 140
 141 void __ax25_put_route(ax25_route *ax25_rt)
 142 {
 143         kfree(ax25_rt->digipeat);
 144         kfree(ax25_rt);
 145 }
 146
 147 static int ax25_rt_del(struct ax25_routes_struct *route)
 148 {
 149         ax25_route *s, *t, *ax25_rt;
 150         ax25_dev *ax25_dev;
 151
 152         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
 153                 return -EINVAL;
 154
 155         write_lock_bh(&ax25_route_lock);
 156
 157         ax25_rt = ax25_route_list;
 158         while (ax25_rt != NULL) {
 159                 s       = ax25_rt;
 160                 ax25_rt = ax25_rt->next;
 161                 if (s->dev == ax25_dev->dev &&
 162                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
 163                         if (ax25_route_list == s) {
 164                                 ax25_route_list = s->next;
 165                                 ax25_put_route(s);
 166                         } else {
 167                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 168                                         if (t->next == s) {
 169                                                 t->next = s->next;
 170                                                 ax25_put_route(s);
 171                                                 break;
 172                                         }
 173                                 }
 174                         }
 175                 }
 176         }
 177         write_unlock_bh(&ax25_route_lock);
 178
 179         return 0;
 180 }
 181
 182 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
 183 {
 184         ax25_route *ax25_rt;
 185         ax25_dev *ax25_dev;
 186         int err = 0;
 187
 188         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
 189                 return -EINVAL;
 190
 191         write_lock_bh(&ax25_route_lock);
 192
 193         ax25_rt = ax25_route_list;
 194         while (ax25_rt != NULL) {
 195                 if (ax25_rt->dev == ax25_dev->dev &&
 196                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
 197                         switch (rt_option->cmd) {
 198                         case AX25_SET_RT_IPMODE:
 199                                 switch (rt_option->arg) {
 200                                 case ' ':
 201                                 case 'D':
 202                                 case 'V':
 203                                         ax25_rt->ip_mode = rt_option->arg;
 204                                         break;
 205                                 default:
 206                                         err = -EINVAL;
 207                                         goto out;
 208                                 }
 209                                 break;
 210                         default:
 211                                 err = -EINVAL;
 212                                 goto out;
 213                         }
 214                 }
 215                 ax25_rt = ax25_rt->next;
 216         }
 217
 218 out:
 219         write_unlock_bh(&ax25_route_lock);
 220         return err;
 221 }
 222
 223 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
 224 {
 225         struct ax25_route_opt_struct rt_option;
 226         struct ax25_routes_struct route;
 227
 228         switch (cmd) {
 229         case SIOCADDRT:
 230                 if (copy_from_user(&route, arg, sizeof(route)))
 231                         return -EFAULT;
 232                 return ax25_rt_add(&route);
 233
 234         case SIOCDELRT:
 235                 if (copy_from_user(&route, arg, sizeof(route)))
 236                         return -EFAULT;
 237                 return ax25_rt_del(&route);
 238
 239         case SIOCAX25OPTRT:
 240                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 241                         return -EFAULT;
 242                 return ax25_rt_opt(&rt_option);
 243
 244         default:
 245                 return -EINVAL;
 246         }
 247 }
 248
 249 #ifdef CONFIG_PROC_FS
 250
 251 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
 252         __acquires(ax25_route_lock)
 253 {
 254         struct ax25_route *ax25_rt;
 255         int i = 1;
 256
 257         read_lock(&ax25_route_lock);
 258         if (*pos == 0)
 259                 return SEQ_START_TOKEN;
 260
 261         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 262                 if (i == *pos)
 263                         return ax25_rt;
 264                 ++i;
 265         }
 266
 267         return NULL;
 268 }
 269
 270 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 271 {
 272         ++*pos;
 273         return (v == SEQ_START_TOKEN) ? ax25_route_list :
 274                 ((struct ax25_route *) v)->next;
 275 }
 276
 277 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
 278         __releases(ax25_route_lock)
 279 {
 280         read_unlock(&ax25_route_lock);
 281 }
 282
 283 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
 284 {
 285         char buf[11];
 286
 287         if (v == SEQ_START_TOKEN)
 288                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 289         else {
 290                 struct ax25_route *ax25_rt = v;
 291                 const char *callsign;
 292                 int i;
 293
 294                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 295                         callsign = "default";
 296                 else
 297                         callsign = ax2asc(buf, &ax25_rt->callsign);
 298
 299                 seq_printf(seq, "%-9s %-4s",
 300                         callsign,
 301                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 302
 303                 switch (ax25_rt->ip_mode) {
 304                 case 'V':
 305                         seq_puts(seq, "   vc");
 306                         break;
 307                 case 'D':
 308                         seq_puts(seq, "   dg");
 309                         break;
 310                 default:
 311                         seq_puts(seq, "    *");
 312                         break;
 313                 }
 314
 315                 if (ax25_rt->digipeat != NULL)
 316                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 317                                 seq_printf(seq, " %s",
 318                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
 319
 320                 seq_puts(seq, "\n");
 321         }
 322         return 0;
 323 }
 324
 325 static const struct seq_operations ax25_rt_seqops = {
 326         .start = ax25_rt_seq_start,
 327         .next = ax25_rt_seq_next,
 328         .stop = ax25_rt_seq_stop,
 329         .show = ax25_rt_seq_show,
 330 };
 331
 332 static int ax25_rt_info_open(struct inode *inode, struct file *file)
 333 {
 334         return seq_open(file, &ax25_rt_seqops);
 335 }
 336
 337 const struct file_operations ax25_route_fops = {
 338         .owner = THIS_MODULE,
 339         .open = ax25_rt_info_open,
 340         .read = seq_read,
 341         .llseek = seq_lseek,
 342         .release = seq_release,
 343 };
 344
 345 #endif
 346
 347 /*
 348  *      Find AX.25 route
 349  *
 350  *      Only routes with a reference count of zero can be destroyed.
 351  */
 352 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 353 {
 354         ax25_route *ax25_spe_rt = NULL;
 355         ax25_route *ax25_def_rt = NULL;
 356         ax25_route *ax25_rt;
 357
 358         read_lock(&ax25_route_lock);
 359         /*
 360          *      Bind to the physical interface we heard them on, or the default
 361          *      route if none is found;
 362          */
 363         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 364                 if (dev == NULL) {
 365                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 366                                 ax25_spe_rt = ax25_rt;
 367                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 368                                 ax25_def_rt = ax25_rt;
 369                 } else {
 370                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 371                                 ax25_spe_rt = ax25_rt;
 372                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 373                                 ax25_def_rt = ax25_rt;
 374                 }
 375         }
 376
 377         ax25_rt = ax25_def_rt;
 378         if (ax25_spe_rt != NULL)
 379                 ax25_rt = ax25_spe_rt;
 380
 381         if (ax25_rt != NULL)
 382                 ax25_hold_route(ax25_rt);
 383
 384         read_unlock(&ax25_route_lock);
 385
 386         return ax25_rt;
 387 }
 388
 389 /*
 390  *      Adjust path: If you specify a default route and want to connect
 391  *      a target on the digipeater path but w/o having a special route
 392  *      set before, the path has to be truncated from your target on.
 393  */
 394 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 395 {
 396         int k;
 397
 398         for (k = 0; k < digipeat->ndigi; k++) {
 399                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 400                         break;
 401         }
 402
 403         digipeat->ndigi = k;
 404 }
 405
 406
 407 /*
 408  *      Find which interface to use.
 409  */
 410 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 411 {
 412         ax25_uid_assoc *user;
 413         ax25_route *ax25_rt;
 414         int err;
 415
 416         if ((ax25_rt = ax25_get_route(addr, NULL)) == NULL)
 417                 return -EHOSTUNREACH;
 418
 419         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 420                 err = -EHOSTUNREACH;
 421                 goto put;
 422         }
 423
 424         user = ax25_findbyuid(current->euid);
 425         if (user) {
 426                 ax25->source_addr = user->call;
 427                 ax25_uid_put(user);
 428         } else {
 429                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 430                         err = -EPERM;
 431                         goto put;
 432                 }
 433                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
 434         }
 435
 436         if (ax25_rt->digipeat != NULL) {
 437                 ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
 438                                          GFP_ATOMIC);
 439                 if (ax25->digipeat == NULL) {
 440                         err = -ENOMEM;
 441                         goto put;
 442                 }
 443                 ax25_adjust_path(addr, ax25->digipeat);
 444         }
 445
 446         if (ax25->sk != NULL) {
 447                 bh_lock_sock(ax25->sk);
 448                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 449                 bh_unlock_sock(ax25->sk);
 450         }
 451
 452 put:
 453         ax25_put_route(ax25_rt);
 454
 455         return 0;
 456 }
 457
 458 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 459         ax25_address *dest, ax25_digi *digi)
 460 {
 461         struct sk_buff *skbn;
 462         unsigned char *bp;
 463         int len;
 464
 465         len = digi->ndigi * AX25_ADDR_LEN;
 466
 467         if (skb_headroom(skb) < len) {
 468                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
 469                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 470                         return NULL;
 471                 }
 472
 473                 if (skb->sk != NULL)
 474                         skb_set_owner_w(skbn, skb->sk);
 475
 476                 kfree_skb(skb);
 477
 478                 skb = skbn;
 479         }
 480
 481         bp = skb_push(skb, len);
 482
 483         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 484
 485         return skb;
 486 }
 487
 488 /*
 489  *      Free all memory associated with routing structures.
 490  */
 491 void __exit ax25_rt_free(void)
 492 {
 493         ax25_route *s, *ax25_rt = ax25_route_list;
 494
 495         write_lock_bh(&ax25_route_lock);
 496         while (ax25_rt != NULL) {
 497                 s       = ax25_rt;
 498                 ax25_rt = ax25_rt->next;
 499
 500                 kfree(s->digipeat);
 501                 kfree(s);
 502         }
 503         write_unlock_bh(&ax25_route_lock);
 504 }