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 <linux/uaccess.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 #include <linux/export.h>
  41
  42 static ax25_route *ax25_route_list;
  43 DEFINE_RWLOCK(ax25_route_lock);
  44
  45 void ax25_rt_device_down(struct net_device *dev)
  46 {
  47         ax25_route *s, *t, *ax25_rt;
  48
  49         write_lock_bh(&ax25_route_lock);
  50         ax25_rt = ax25_route_list;
  51         while (ax25_rt != NULL) {
  52                 s       = ax25_rt;
  53                 ax25_rt = ax25_rt->next;
  54
  55                 if (s->dev == dev) {
  56                         if (ax25_route_list == s) {
  57                                 ax25_route_list = s->next;
  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                                                 kfree(s->digipeat);
  65                                                 kfree(s);
  66                                                 break;
  67                                         }
  68                                 }
  69                         }
  70                 }
  71         }
  72         write_unlock_bh(&ax25_route_lock);
  73 }
  74
  75 static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
  76 {
  77         ax25_route *ax25_rt;
  78         ax25_dev *ax25_dev;
  79         int i;
  80
  81         if (route->digi_count > AX25_MAX_DIGIS)
  82                 return -EINVAL;
  83
  84         ax25_dev = ax25_addr_ax25dev(&route->port_addr);
  85         if (!ax25_dev)
  86                 return -EINVAL;
  87
  88         write_lock_bh(&ax25_route_lock);
  89
  90         ax25_rt = ax25_route_list;
  91         while (ax25_rt != NULL) {
  92                 if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
  93                             ax25_rt->dev == ax25_dev->dev) {
  94                         kfree(ax25_rt->digipeat);
  95                         ax25_rt->digipeat = NULL;
  96                         if (route->digi_count != 0) {
  97                                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
  98                                         write_unlock_bh(&ax25_route_lock);
  99                                         ax25_dev_put(ax25_dev);
 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_bh(&ax25_route_lock);
 110                         ax25_dev_put(ax25_dev);
 111                         return 0;
 112                 }
 113                 ax25_rt = ax25_rt->next;
 114         }
 115
 116         if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
 117                 write_unlock_bh(&ax25_route_lock);
 118                 ax25_dev_put(ax25_dev);
 119                 return -ENOMEM;
 120         }
 121
 122         refcount_set(&ax25_rt->refcount, 1);
 123         ax25_rt->callsign     = route->dest_addr;
 124         ax25_rt->dev          = ax25_dev->dev;
 125         ax25_rt->digipeat     = NULL;
 126         ax25_rt->ip_mode      = ' ';
 127         if (route->digi_count != 0) {
 128                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
 129                         write_unlock_bh(&ax25_route_lock);
 130                         kfree(ax25_rt);
 131                         ax25_dev_put(ax25_dev);
 132                         return -ENOMEM;
 133                 }
 134                 ax25_rt->digipeat->lastrepeat = -1;
 135                 ax25_rt->digipeat->ndigi      = route->digi_count;
 136                 for (i = 0; i < route->digi_count; i++) {
 137                         ax25_rt->digipeat->repeated[i] = 0;
 138                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
 139                 }
 140         }
 141         ax25_rt->next   = ax25_route_list;
 142         ax25_route_list = ax25_rt;
 143         write_unlock_bh(&ax25_route_lock);
 144         ax25_dev_put(ax25_dev);
 145
 146         return 0;
 147 }
 148
 149 void __ax25_put_route(ax25_route *ax25_rt)
 150 {
 151         kfree(ax25_rt->digipeat);
 152         kfree(ax25_rt);
 153 }
 154
 155 static int ax25_rt_del(struct ax25_routes_struct *route)
 156 {
 157         ax25_route *s, *t, *ax25_rt;
 158         ax25_dev *ax25_dev;
 159
 160         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
 161                 return -EINVAL;
 162
 163         write_lock_bh(&ax25_route_lock);
 164
 165         ax25_rt = ax25_route_list;
 166         while (ax25_rt != NULL) {
 167                 s       = ax25_rt;
 168                 ax25_rt = ax25_rt->next;
 169                 if (s->dev == ax25_dev->dev &&
 170                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
 171                         if (ax25_route_list == s) {
 172                                 ax25_route_list = s->next;
 173                                 ax25_put_route(s);
 174                         } else {
 175                                 for (t = ax25_route_list; t != NULL; t = t->next) {
 176                                         if (t->next == s) {
 177                                                 t->next = s->next;
 178                                                 ax25_put_route(s);
 179                                                 break;
 180                                         }
 181                                 }
 182                         }
 183                 }
 184         }
 185         write_unlock_bh(&ax25_route_lock);
 186         ax25_dev_put(ax25_dev);
 187
 188         return 0;
 189 }
 190
 191 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
 192 {
 193         ax25_route *ax25_rt;
 194         ax25_dev *ax25_dev;
 195         int err = 0;
 196
 197         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
 198                 return -EINVAL;
 199
 200         write_lock_bh(&ax25_route_lock);
 201
 202         ax25_rt = ax25_route_list;
 203         while (ax25_rt != NULL) {
 204                 if (ax25_rt->dev == ax25_dev->dev &&
 205                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
 206                         switch (rt_option->cmd) {
 207                         case AX25_SET_RT_IPMODE:
 208                                 switch (rt_option->arg) {
 209                                 case ' ':
 210                                 case 'D':
 211                                 case 'V':
 212                                         ax25_rt->ip_mode = rt_option->arg;
 213                                         break;
 214                                 default:
 215                                         err = -EINVAL;
 216                                         goto out;
 217                                 }
 218                                 break;
 219                         default:
 220                                 err = -EINVAL;
 221                                 goto out;
 222                         }
 223                 }
 224                 ax25_rt = ax25_rt->next;
 225         }
 226
 227 out:
 228         write_unlock_bh(&ax25_route_lock);
 229         ax25_dev_put(ax25_dev);
 230         return err;
 231 }
 232
 233 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
 234 {
 235         struct ax25_route_opt_struct rt_option;
 236         struct ax25_routes_struct route;
 237
 238         switch (cmd) {
 239         case SIOCADDRT:
 240                 if (copy_from_user(&route, arg, sizeof(route)))
 241                         return -EFAULT;
 242                 return ax25_rt_add(&route);
 243
 244         case SIOCDELRT:
 245                 if (copy_from_user(&route, arg, sizeof(route)))
 246                         return -EFAULT;
 247                 return ax25_rt_del(&route);
 248
 249         case SIOCAX25OPTRT:
 250                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
 251                         return -EFAULT;
 252                 return ax25_rt_opt(&rt_option);
 253
 254         default:
 255                 return -EINVAL;
 256         }
 257 }
 258
 259 #ifdef CONFIG_PROC_FS
 260
 261 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
 262         __acquires(ax25_route_lock)
 263 {
 264         struct ax25_route *ax25_rt;
 265         int i = 1;
 266
 267         read_lock(&ax25_route_lock);
 268         if (*pos == 0)
 269                 return SEQ_START_TOKEN;
 270
 271         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 272                 if (i == *pos)
 273                         return ax25_rt;
 274                 ++i;
 275         }
 276
 277         return NULL;
 278 }
 279
 280 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 281 {
 282         ++*pos;
 283         return (v == SEQ_START_TOKEN) ? ax25_route_list :
 284                 ((struct ax25_route *) v)->next;
 285 }
 286
 287 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
 288         __releases(ax25_route_lock)
 289 {
 290         read_unlock(&ax25_route_lock);
 291 }
 292
 293 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
 294 {
 295         char buf[11];
 296
 297         if (v == SEQ_START_TOKEN)
 298                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
 299         else {
 300                 struct ax25_route *ax25_rt = v;
 301                 const char *callsign;
 302                 int i;
 303
 304                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
 305                         callsign = "default";
 306                 else
 307                         callsign = ax2asc(buf, &ax25_rt->callsign);
 308
 309                 seq_printf(seq, "%-9s %-4s",
 310                         callsign,
 311                         ax25_rt->dev ? ax25_rt->dev->name : "???");
 312
 313                 switch (ax25_rt->ip_mode) {
 314                 case 'V':
 315                         seq_puts(seq, "   vc");
 316                         break;
 317                 case 'D':
 318                         seq_puts(seq, "   dg");
 319                         break;
 320                 default:
 321                         seq_puts(seq, "    *");
 322                         break;
 323                 }
 324
 325                 if (ax25_rt->digipeat != NULL)
 326                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
 327                                 seq_printf(seq, " %s",
 328                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
 329
 330                 seq_puts(seq, "\n");
 331         }
 332         return 0;
 333 }
 334
 335 static const struct seq_operations ax25_rt_seqops = {
 336         .start = ax25_rt_seq_start,
 337         .next = ax25_rt_seq_next,
 338         .stop = ax25_rt_seq_stop,
 339         .show = ax25_rt_seq_show,
 340 };
 341
 342 static int ax25_rt_info_open(struct inode *inode, struct file *file)
 343 {
 344         return seq_open(file, &ax25_rt_seqops);
 345 }
 346
 347 const struct file_operations ax25_route_fops = {
 348         .owner = THIS_MODULE,
 349         .open = ax25_rt_info_open,
 350         .read = seq_read,
 351         .llseek = seq_lseek,
 352         .release = seq_release,
 353 };
 354
 355 #endif
 356
 357 /*
 358  *      Find AX.25 route
 359  *
 360  *      Only routes with a reference count of zero can be destroyed.
 361  *      Must be called with ax25_route_lock read locked.
 362  */
 363 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
 364 {
 365         ax25_route *ax25_spe_rt = NULL;
 366         ax25_route *ax25_def_rt = NULL;
 367         ax25_route *ax25_rt;
 368
 369         /*
 370          *      Bind to the physical interface we heard them on, or the default
 371          *      route if none is found;
 372          */
 373         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
 374                 if (dev == NULL) {
 375                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
 376                                 ax25_spe_rt = ax25_rt;
 377                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
 378                                 ax25_def_rt = ax25_rt;
 379                 } else {
 380                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
 381                                 ax25_spe_rt = ax25_rt;
 382                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
 383                                 ax25_def_rt = ax25_rt;
 384                 }
 385         }
 386
 387         ax25_rt = ax25_def_rt;
 388         if (ax25_spe_rt != NULL)
 389                 ax25_rt = ax25_spe_rt;
 390
 391         return ax25_rt;
 392 }
 393
 394 /*
 395  *      Adjust path: If you specify a default route and want to connect
 396  *      a target on the digipeater path but w/o having a special route
 397  *      set before, the path has to be truncated from your target on.
 398  */
 399 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
 400 {
 401         int k;
 402
 403         for (k = 0; k < digipeat->ndigi; k++) {
 404                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
 405                         break;
 406         }
 407
 408         digipeat->ndigi = k;
 409 }
 410
 411
 412 /*
 413  *      Find which interface to use.
 414  */
 415 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 416 {
 417         ax25_uid_assoc *user;
 418         ax25_route *ax25_rt;
 419         int err = 0;
 420
 421         ax25_route_lock_use();
 422         ax25_rt = ax25_get_route(addr, NULL);
 423         if (!ax25_rt) {
 424                 ax25_route_lock_unuse();
 425                 return -EHOSTUNREACH;
 426         }
 427         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
 428                 err = -EHOSTUNREACH;
 429                 goto put;
 430         }
 431
 432         user = ax25_findbyuid(current_euid());
 433         if (user) {
 434                 ax25->source_addr = user->call;
 435                 ax25_uid_put(user);
 436         } else {
 437                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 438                         err = -EPERM;
 439                         goto put;
 440                 }
 441                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
 442         }
 443
 444         if (ax25_rt->digipeat != NULL) {
 445                 ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
 446                                          GFP_ATOMIC);
 447                 if (ax25->digipeat == NULL) {
 448                         err = -ENOMEM;
 449                         goto put;
 450                 }
 451                 ax25_adjust_path(addr, ax25->digipeat);
 452         }
 453
 454         if (ax25->sk != NULL) {
 455                 local_bh_disable();
 456                 bh_lock_sock(ax25->sk);
 457                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
 458                 bh_unlock_sock(ax25->sk);
 459                 local_bh_enable();
 460         }
 461
 462 put:
 463         ax25_route_lock_unuse();
 464         return err;
 465 }
 466
 467 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
 468         ax25_address *dest, ax25_digi *digi)
 469 {
 470         struct sk_buff *skbn;
 471         unsigned char *bp;
 472         int len;
 473
 474         len = digi->ndigi * AX25_ADDR_LEN;
 475
 476         if (skb_headroom(skb) < len) {
 477                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
 478                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
 479                         return NULL;
 480                 }
 481
 482                 if (skb->sk != NULL)
 483                         skb_set_owner_w(skbn, skb->sk);
 484
 485                 consume_skb(skb);
 486
 487                 skb = skbn;
 488         }
 489
 490         bp = skb_push(skb, len);
 491
 492         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
 493
 494         return skb;
 495 }
 496
 497 /*
 498  *      Free all memory associated with routing structures.
 499  */
 500 void __exit ax25_rt_free(void)
 501 {
 502         ax25_route *s, *ax25_rt = ax25_route_list;
 503
 504         write_lock_bh(&ax25_route_lock);
 505         while (ax25_rt != NULL) {
 506                 s       = ax25_rt;
 507                 ax25_rt = ax25_rt->next;
 508
 509                 kfree(s->digipeat);
 510                 kfree(s);
 511         }
 512         write_unlock_bh(&ax25_route_lock);
 513 }