drivers/staging/batman-adv/vis.c

   1 /*
   2  * Copyright (C) 2008-2010 B.A.T.M.A.N. contributors:
   3  *
   4  * Simon Wunderlich
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA
  19  *
  20  */
  21
  22 #include "main.h"
  23 #include "send.h"
  24 #include "translation-table.h"
  25 #include "vis.h"
  26 #include "soft-interface.h"
  27 #include "hard-interface.h"
  28 #include "hash.h"
  29
  30 /* Returns the smallest signed integer in two's complement with the sizeof x */
  31 #define smallest_signed_int(x) (1u << (7u + 8u * (sizeof(x) - 1u)))
  32
  33 /* Checks if a sequence number x is a predecessor/successor of y.
  34    they handle overflows/underflows and can correctly check for a
  35    predecessor/successor unless the variable sequence number has grown by
  36    more then 2**(bitwidth(x)-1)-1.
  37    This means that for a uint8_t with the maximum value 255, it would think:
  38     * when adding nothing - it is neither a predecessor nor a successor
  39     * before adding more than 127 to the starting value - it is a predecessor,
  40     * when adding 128 - it is neither a predecessor nor a successor,
  41     * after adding more than 127 to the starting value - it is a successor */
  42 #define seq_before(x, y) ({typeof(x) _dummy = (x - y); \
  43                           _dummy > smallest_signed_int(_dummy); })
  44 #define seq_after(x, y) seq_before(y, x)
  45
  46 struct hashtable_t *vis_hash;
  47 DEFINE_SPINLOCK(vis_hash_lock);
  48 static DEFINE_SPINLOCK(recv_list_lock);
  49 static struct vis_info *my_vis_info;
  50 static struct list_head send_list;      /* always locked with vis_hash_lock */
  51
  52 static void start_vis_timer(void);
  53
  54 /* free the info */
  55 static void free_info(struct kref *ref)
  56 {
  57         struct vis_info *info = container_of(ref, struct vis_info, refcount);
  58         struct recvlist_node *entry, *tmp;
  59         unsigned long flags;
  60
  61         list_del_init(&info->send_list);
  62         spin_lock_irqsave(&recv_list_lock, flags);
  63         list_for_each_entry_safe(entry, tmp, &info->recv_list, list) {
  64                 list_del(&entry->list);
  65                 kfree(entry);
  66         }
  67         spin_unlock_irqrestore(&recv_list_lock, flags);
  68         kfree(info);
  69 }
  70
  71 /* Compare two vis packets, used by the hashing algorithm */
  72 static int vis_info_cmp(void *data1, void *data2)
  73 {
  74         struct vis_info *d1, *d2;
  75         d1 = data1;
  76         d2 = data2;
  77         return compare_orig(d1->packet.vis_orig, d2->packet.vis_orig);
  78 }
  79
  80 /* hash function to choose an entry in a hash table of given size */
  81 /* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */
  82 static int vis_info_choose(void *data, int size)
  83 {
  84         struct vis_info *vis_info = data;
  85         unsigned char *key;
  86         uint32_t hash = 0;
  87         size_t i;
  88
  89         key = vis_info->packet.vis_orig;
  90         for (i = 0; i < ETH_ALEN; i++) {
  91                 hash += key[i];
  92                 hash += (hash << 10);
  93                 hash ^= (hash >> 6);
  94         }
  95
  96         hash += (hash << 3);
  97         hash ^= (hash >> 11);
  98         hash += (hash << 15);
  99
 100         return hash % size;
 101 }
 102
 103 /* insert interface to the list of interfaces of one originator, if it
 104  * does not already exist in the list */
 105 void proc_vis_insert_interface(const uint8_t *interface,
 106                                       struct hlist_head *if_list,
 107                                       bool primary)
 108 {
 109         struct if_list_entry *entry;
 110         struct hlist_node *pos;
 111
 112         hlist_for_each_entry(entry, pos, if_list, list) {
 113                 if (compare_orig(entry->addr, (void *)interface))
 114                         return;
 115         }
 116
 117         /* its a new address, add it to the list */
 118         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 119         if (!entry)
 120                 return;
 121         memcpy(entry->addr, interface, ETH_ALEN);
 122         entry->primary = primary;
 123         hlist_add_head(&entry->list, if_list);
 124 }
 125
 126 void proc_vis_read_prim_sec(struct seq_file *seq,
 127                             struct hlist_head *if_list)
 128 {
 129         struct if_list_entry *entry;
 130         struct hlist_node *pos;
 131         char tmp_addr_str[ETH_STR_LEN];
 132
 133         hlist_for_each_entry(entry, pos, if_list, list) {
 134                 if (entry->primary)
 135                         seq_printf(seq, "PRIMARY, ");
 136                 else {
 137                         addr_to_string(tmp_addr_str, entry->addr);
 138                         seq_printf(seq, "SEC %s, ", tmp_addr_str);
 139                 }
 140         }
 141 }
 142
 143 /* read an entry  */
 144 void proc_vis_read_entry(struct seq_file *seq,
 145                                 struct vis_info_entry *entry,
 146                                 uint8_t *src,
 147                                 bool primary)
 148 {
 149         char to[40];
 150
 151         addr_to_string(to, entry->dest);
 152         if (primary && entry->quality == 0)
 153                 seq_printf(seq, "HNA %s, ", to);
 154         else if (compare_orig(entry->src, src))
 155                 seq_printf(seq, "TQ %s %d, ", to, entry->quality);
 156 }
 157
 158 /* add the info packet to the send list, if it was not
 159  * already linked in. */
 160 static void send_list_add(struct vis_info *info)
 161 {
 162         if (list_empty(&info->send_list)) {
 163                 kref_get(&info->refcount);
 164                 list_add_tail(&info->send_list, &send_list);
 165         }
 166 }
 167
 168 /* delete the info packet from the send list, if it was
 169  * linked in. */
 170 static void send_list_del(struct vis_info *info)
 171 {
 172         if (!list_empty(&info->send_list)) {
 173                 list_del_init(&info->send_list);
 174                 kref_put(&info->refcount, free_info);
 175         }
 176 }
 177
 178 /* tries to add one entry to the receive list. */
 179 static void recv_list_add(struct list_head *recv_list, char *mac)
 180 {
 181         struct recvlist_node *entry;
 182         unsigned long flags;
 183
 184         entry = kmalloc(sizeof(struct recvlist_node), GFP_ATOMIC);
 185         if (!entry)
 186                 return;
 187
 188         memcpy(entry->mac, mac, ETH_ALEN);
 189         spin_lock_irqsave(&recv_list_lock, flags);
 190         list_add_tail(&entry->list, recv_list);
 191         spin_unlock_irqrestore(&recv_list_lock, flags);
 192 }
 193
 194 /* returns 1 if this mac is in the recv_list */
 195 static int recv_list_is_in(struct list_head *recv_list, char *mac)
 196 {
 197         struct recvlist_node *entry;
 198         unsigned long flags;
 199
 200         spin_lock_irqsave(&recv_list_lock, flags);
 201         list_for_each_entry(entry, recv_list, list) {
 202                 if (memcmp(entry->mac, mac, ETH_ALEN) == 0) {
 203                         spin_unlock_irqrestore(&recv_list_lock, flags);
 204                         return 1;
 205                 }
 206         }
 207         spin_unlock_irqrestore(&recv_list_lock, flags);
 208         return 0;
 209 }
 210
 211 /* try to add the packet to the vis_hash. return NULL if invalid (e.g. too old,
 212  * broken.. ).  vis hash must be locked outside.  is_new is set when the packet
 213  * is newer than old entries in the hash. */
 214 static struct vis_info *add_packet(struct vis_packet *vis_packet,
 215                                    int vis_info_len, int *is_new,
 216                                    int make_broadcast)
 217 {
 218         struct vis_info *info, *old_info;
 219         struct vis_info search_elem;
 220
 221         *is_new = 0;
 222         /* sanity check */
 223         if (vis_hash == NULL)
 224                 return NULL;
 225
 226         /* see if the packet is already in vis_hash */
 227         memcpy(search_elem.packet.vis_orig, vis_packet->vis_orig, ETH_ALEN);
 228         old_info = hash_find(vis_hash, &search_elem);
 229
 230         if (old_info != NULL) {
 231                 if (!seq_after(vis_packet->seqno, old_info->packet.seqno)) {
 232                         if (old_info->packet.seqno == vis_packet->seqno) {
 233                                 recv_list_add(&old_info->recv_list,
 234                                               vis_packet->sender_orig);
 235                                 return old_info;
 236                         } else {
 237                                 /* newer packet is already in hash. */
 238                                 return NULL;
 239                         }
 240                 }
 241                 /* remove old entry */
 242                 hash_remove(vis_hash, old_info);
 243                 send_list_del(old_info);
 244                 kref_put(&old_info->refcount, free_info);
 245         }
 246
 247         info = kmalloc(sizeof(struct vis_info) + vis_info_len, GFP_ATOMIC);
 248         if (info == NULL)
 249                 return NULL;
 250
 251         kref_init(&info->refcount);
 252         INIT_LIST_HEAD(&info->send_list);
 253         INIT_LIST_HEAD(&info->recv_list);
 254         info->first_seen = jiffies;
 255         memcpy(&info->packet, vis_packet,
 256                sizeof(struct vis_packet) + vis_info_len);
 257
 258         /* initialize and add new packet. */
 259         *is_new = 1;
 260
 261         /* Make it a broadcast packet, if required */
 262         if (make_broadcast)
 263                 memcpy(info->packet.target_orig, broadcastAddr, ETH_ALEN);
 264
 265         /* repair if entries is longer than packet. */
 266         if (info->packet.entries * sizeof(struct vis_info_entry) > vis_info_len)
 267                 info->packet.entries = vis_info_len /
 268                         sizeof(struct vis_info_entry);
 269
 270         recv_list_add(&info->recv_list, info->packet.sender_orig);
 271
 272         /* try to add it */
 273         if (hash_add(vis_hash, info) < 0) {
 274                 /* did not work (for some reason) */
 275                 kref_put(&old_info->refcount, free_info);
 276                 info = NULL;
 277         }
 278
 279         return info;
 280 }
 281
 282 /* handle the server sync packet, forward if needed. */
 283 void receive_server_sync_packet(struct vis_packet *vis_packet, int vis_info_len)
 284 {
 285         struct vis_info *info;
 286         int is_new, make_broadcast;
 287         unsigned long flags;
 288         int vis_server = atomic_read(&vis_mode);
 289
 290         make_broadcast = (vis_server == VIS_TYPE_SERVER_SYNC);
 291
 292         spin_lock_irqsave(&vis_hash_lock, flags);
 293         info = add_packet(vis_packet, vis_info_len, &is_new, make_broadcast);
 294         if (info == NULL)
 295                 goto end;
 296
 297         /* only if we are server ourselves and packet is newer than the one in
 298          * hash.*/
 299         if (vis_server == VIS_TYPE_SERVER_SYNC && is_new)
 300                 send_list_add(info);
 301 end:
 302         spin_unlock_irqrestore(&vis_hash_lock, flags);
 303 }
 304
 305 /* handle an incoming client update packet and schedule forward if needed. */
 306 void receive_client_update_packet(struct vis_packet *vis_packet,
 307                                   int vis_info_len)
 308 {
 309         struct vis_info *info;
 310         int is_new;
 311         unsigned long flags;
 312         int vis_server = atomic_read(&vis_mode);
 313         int are_target = 0;
 314
 315         /* clients shall not broadcast. */
 316         if (is_bcast(vis_packet->target_orig))
 317                 return;
 318
 319         /* Are we the target for this VIS packet? */
 320         if (vis_server == VIS_TYPE_SERVER_SYNC  &&
 321             is_my_mac(vis_packet->target_orig))
 322                 are_target = 1;
 323
 324         spin_lock_irqsave(&vis_hash_lock, flags);
 325         info = add_packet(vis_packet, vis_info_len, &is_new, are_target);
 326         if (info == NULL)
 327                 goto end;
 328         /* note that outdated packets will be dropped at this point. */
 329
 330
 331         /* send only if we're the target server or ... */
 332         if (are_target && is_new) {
 333                 info->packet.vis_type = VIS_TYPE_SERVER_SYNC;   /* upgrade! */
 334                 send_list_add(info);
 335
 336                 /* ... we're not the recipient (and thus need to forward). */
 337         } else if (!is_my_mac(info->packet.target_orig)) {
 338                 send_list_add(info);
 339         }
 340 end:
 341         spin_unlock_irqrestore(&vis_hash_lock, flags);
 342 }
 343
 344 /* Walk the originators and find the VIS server with the best tq. Set the packet
 345  * address to its address and return the best_tq.
 346  *
 347  * Must be called with the originator hash locked */
 348 static int find_best_vis_server(struct vis_info *info)
 349 {
 350         HASHIT(hashit);
 351         struct orig_node *orig_node;
 352         int best_tq = -1;
 353
 354         while (hash_iterate(orig_hash, &hashit)) {
 355                 orig_node = hashit.bucket->data;
 356                 if ((orig_node != NULL) &&
 357                     (orig_node->router != NULL) &&
 358                     (orig_node->flags & VIS_SERVER) &&
 359                     (orig_node->router->tq_avg > best_tq)) {
 360                         best_tq = orig_node->router->tq_avg;
 361                         memcpy(info->packet.target_orig, orig_node->orig,
 362                                ETH_ALEN);
 363                 }
 364         }
 365         return best_tq;
 366 }
 367
 368 /* Return true if the vis packet is full. */
 369 static bool vis_packet_full(struct vis_info *info)
 370 {
 371         if (info->packet.entries + 1 >
 372             (1000 - sizeof(struct vis_info)) / sizeof(struct vis_info_entry))
 373                 return true;
 374         return false;
 375 }
 376
 377 /* generates a packet of own vis data,
 378  * returns 0 on success, -1 if no packet could be generated */
 379 static int generate_vis_packet(void)
 380 {
 381         HASHIT(hashit_local);
 382         HASHIT(hashit_global);
 383         struct orig_node *orig_node;
 384         struct vis_info *info = (struct vis_info *)my_vis_info;
 385         struct vis_info_entry *entry, *entry_array;
 386         struct hna_local_entry *hna_local_entry;
 387         int best_tq = -1;
 388         unsigned long flags;
 389
 390         info->first_seen = jiffies;
 391         info->packet.vis_type = atomic_read(&vis_mode);
 392
 393         spin_lock_irqsave(&orig_hash_lock, flags);
 394         memcpy(info->packet.target_orig, broadcastAddr, ETH_ALEN);
 395         info->packet.ttl = TTL;
 396         info->packet.seqno++;
 397         info->packet.entries = 0;
 398
 399         if (info->packet.vis_type == VIS_TYPE_CLIENT_UPDATE) {
 400                 best_tq = find_best_vis_server(info);
 401                 if (best_tq < 0) {
 402                         spin_unlock_irqrestore(&orig_hash_lock, flags);
 403                         return -1;
 404                 }
 405         }
 406
 407         entry_array = (struct vis_info_entry *)
 408                 ((char *)info + sizeof(struct vis_info));
 409
 410         while (hash_iterate(orig_hash, &hashit_global)) {
 411                 orig_node = hashit_global.bucket->data;
 412                 if (orig_node->router != NULL
 413                         && compare_orig(orig_node->router->addr,
 414                                         orig_node->orig)
 415                         && orig_node->batman_if
 416                         && (orig_node->batman_if->if_active == IF_ACTIVE)
 417                     && orig_node->router->tq_avg > 0) {
 418
 419                         /* fill one entry into buffer. */
 420                         entry = &entry_array[info->packet.entries];
 421                         memcpy(entry->src,
 422                                orig_node->batman_if->net_dev->dev_addr,
 423                                ETH_ALEN);
 424                         memcpy(entry->dest, orig_node->orig, ETH_ALEN);
 425                         entry->quality = orig_node->router->tq_avg;
 426                         info->packet.entries++;
 427
 428                         if (vis_packet_full(info)) {
 429                                 spin_unlock_irqrestore(&orig_hash_lock, flags);
 430                                 return 0;
 431                         }
 432                 }
 433         }
 434
 435         spin_unlock_irqrestore(&orig_hash_lock, flags);
 436
 437         spin_lock_irqsave(&hna_local_hash_lock, flags);
 438         while (hash_iterate(hna_local_hash, &hashit_local)) {
 439                 hna_local_entry = hashit_local.bucket->data;
 440                 entry = &entry_array[info->packet.entries];
 441                 memset(entry->src, 0, ETH_ALEN);
 442                 memcpy(entry->dest, hna_local_entry->addr, ETH_ALEN);
 443                 entry->quality = 0; /* 0 means HNA */
 444                 info->packet.entries++;
 445
 446                 if (vis_packet_full(info)) {
 447                         spin_unlock_irqrestore(&hna_local_hash_lock, flags);
 448                         return 0;
 449                 }
 450         }
 451         spin_unlock_irqrestore(&hna_local_hash_lock, flags);
 452         return 0;
 453 }
 454
 455 /* free old vis packets. Must be called with this vis_hash_lock
 456  * held */
 457 static void purge_vis_packets(void)
 458 {
 459         HASHIT(hashit);
 460         struct vis_info *info;
 461
 462         while (hash_iterate(vis_hash, &hashit)) {
 463                 info = hashit.bucket->data;
 464                 if (info == my_vis_info)        /* never purge own data. */
 465                         continue;
 466                 if (time_after(jiffies,
 467                                info->first_seen + (VIS_TIMEOUT*HZ)/1000)) {
 468                         hash_remove_bucket(vis_hash, &hashit);
 469                         send_list_del(info);
 470                         kref_put(&info->refcount, free_info);
 471                 }
 472         }
 473 }
 474
 475 static void broadcast_vis_packet(struct vis_info *info, int packet_length)
 476 {
 477         HASHIT(hashit);
 478         struct orig_node *orig_node;
 479         unsigned long flags;
 480         struct batman_if *batman_if;
 481         uint8_t dstaddr[ETH_ALEN];
 482
 483         spin_lock_irqsave(&orig_hash_lock, flags);
 484
 485         /* send to all routers in range. */
 486         while (hash_iterate(orig_hash, &hashit)) {
 487                 orig_node = hashit.bucket->data;
 488
 489                 /* if it's a vis server and reachable, send it. */
 490                 if ((!orig_node) || (!orig_node->batman_if) ||
 491                     (!orig_node->router))
 492                         continue;
 493                 if (!(orig_node->flags & VIS_SERVER))
 494                         continue;
 495                 /* don't send it if we already received the packet from
 496                  * this node. */
 497                 if (recv_list_is_in(&info->recv_list, orig_node->orig))
 498                         continue;
 499
 500                 memcpy(info->packet.target_orig, orig_node->orig, ETH_ALEN);
 501                 batman_if = orig_node->batman_if;
 502                 memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);
 503                 spin_unlock_irqrestore(&orig_hash_lock, flags);
 504
 505                 send_raw_packet((unsigned char *)&info->packet,
 506                                 packet_length, batman_if, dstaddr);
 507
 508                 spin_lock_irqsave(&orig_hash_lock, flags);
 509
 510         }
 511         spin_unlock_irqrestore(&orig_hash_lock, flags);
 512         memcpy(info->packet.target_orig, broadcastAddr, ETH_ALEN);
 513 }
 514
 515 static void unicast_vis_packet(struct vis_info *info, int packet_length)
 516 {
 517         struct orig_node *orig_node;
 518         unsigned long flags;
 519         struct batman_if *batman_if;
 520         uint8_t dstaddr[ETH_ALEN];
 521
 522         spin_lock_irqsave(&orig_hash_lock, flags);
 523         orig_node = ((struct orig_node *)
 524                      hash_find(orig_hash, info->packet.target_orig));
 525
 526         if ((!orig_node) || (!orig_node->batman_if) || (!orig_node->router))
 527                 goto out;
 528
 529         /* don't lock while sending the packets ... we therefore
 530          * copy the required data before sending */
 531         batman_if = orig_node->batman_if;
 532         memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);
 533         spin_unlock_irqrestore(&orig_hash_lock, flags);
 534
 535         send_raw_packet((unsigned char *)&info->packet,
 536                         packet_length, batman_if, dstaddr);
 537         return;
 538
 539 out:
 540         spin_unlock_irqrestore(&orig_hash_lock, flags);
 541 }
 542
 543 /* only send one vis packet. called from send_vis_packets() */
 544 static void send_vis_packet(struct vis_info *info)
 545 {
 546         int packet_length;
 547
 548         if (info->packet.ttl < 2) {
 549                 printk(KERN_WARNING "batman-adv: Error - can't send vis packet: ttl exceeded\n");
 550                 return;
 551         }
 552
 553         memcpy(info->packet.sender_orig, mainIfAddr, ETH_ALEN);
 554         info->packet.ttl--;
 555
 556         packet_length = sizeof(struct vis_packet) +
 557                 info->packet.entries * sizeof(struct vis_info_entry);
 558
 559         if (is_bcast(info->packet.target_orig))
 560                 broadcast_vis_packet(info, packet_length);
 561         else
 562                 unicast_vis_packet(info, packet_length);
 563         info->packet.ttl++; /* restore TTL */
 564 }
 565
 566 /* called from timer; send (and maybe generate) vis packet. */
 567 static void send_vis_packets(struct work_struct *work)
 568 {
 569         struct vis_info *info, *temp;
 570         unsigned long flags;
 571
 572         spin_lock_irqsave(&vis_hash_lock, flags);
 573
 574         purge_vis_packets();
 575
 576         if (generate_vis_packet() == 0) {
 577                 /* schedule if generation was successful */
 578                 send_list_add(my_vis_info);
 579         }
 580
 581         list_for_each_entry_safe(info, temp, &send_list, send_list) {
 582
 583                 kref_get(&info->refcount);
 584                 spin_unlock_irqrestore(&vis_hash_lock, flags);
 585
 586                 send_vis_packet(info);
 587
 588                 spin_lock_irqsave(&vis_hash_lock, flags);
 589                 send_list_del(info);
 590                 kref_put(&info->refcount, free_info);
 591         }
 592         spin_unlock_irqrestore(&vis_hash_lock, flags);
 593         start_vis_timer();
 594 }
 595 static DECLARE_DELAYED_WORK(vis_timer_wq, send_vis_packets);
 596
 597 /* init the vis server. this may only be called when if_list is already
 598  * initialized (e.g. bat0 is initialized, interfaces have been added) */
 599 int vis_init(void)
 600 {
 601         unsigned long flags;
 602         if (vis_hash)
 603                 return 1;
 604
 605         spin_lock_irqsave(&vis_hash_lock, flags);
 606
 607         vis_hash = hash_new(256, vis_info_cmp, vis_info_choose);
 608         if (!vis_hash) {
 609                 printk(KERN_ERR "batman-adv:Can't initialize vis_hash\n");
 610                 goto err;
 611         }
 612
 613         my_vis_info = kmalloc(1000, GFP_ATOMIC);
 614         if (!my_vis_info) {
 615                 printk(KERN_ERR "batman-adv:Can't initialize vis packet\n");
 616                 goto err;
 617         }
 618
 619         /* prefill the vis info */
 620         my_vis_info->first_seen = jiffies - atomic_read(&vis_interval);
 621         INIT_LIST_HEAD(&my_vis_info->recv_list);
 622         INIT_LIST_HEAD(&my_vis_info->send_list);
 623         kref_init(&my_vis_info->refcount);
 624         my_vis_info->packet.version = COMPAT_VERSION;
 625         my_vis_info->packet.packet_type = BAT_VIS;
 626         my_vis_info->packet.ttl = TTL;
 627         my_vis_info->packet.seqno = 0;
 628         my_vis_info->packet.entries = 0;
 629
 630         INIT_LIST_HEAD(&send_list);
 631
 632         memcpy(my_vis_info->packet.vis_orig, mainIfAddr, ETH_ALEN);
 633         memcpy(my_vis_info->packet.sender_orig, mainIfAddr, ETH_ALEN);
 634
 635         if (hash_add(vis_hash, my_vis_info) < 0) {
 636                 printk(KERN_ERR
 637                        "batman-adv:Can't add own vis packet into hash\n");
 638                 /* not in hash, need to remove it manually. */
 639                 kref_put(&my_vis_info->refcount, free_info);
 640                 goto err;
 641         }
 642
 643         spin_unlock_irqrestore(&vis_hash_lock, flags);
 644         start_vis_timer();
 645         return 1;
 646
 647 err:
 648         spin_unlock_irqrestore(&vis_hash_lock, flags);
 649         vis_quit();
 650         return 0;
 651 }
 652
 653 /* Decrease the reference count on a hash item info */
 654 static void free_info_ref(void *data)
 655 {
 656         struct vis_info *info = data;
 657
 658         send_list_del(info);
 659         kref_put(&info->refcount, free_info);
 660 }
 661
 662 /* shutdown vis-server */
 663 void vis_quit(void)
 664 {
 665         unsigned long flags;
 666         if (!vis_hash)
 667                 return;
 668
 669         cancel_delayed_work_sync(&vis_timer_wq);
 670
 671         spin_lock_irqsave(&vis_hash_lock, flags);
 672         /* properly remove, kill timers ... */
 673         hash_delete(vis_hash, free_info_ref);
 674         vis_hash = NULL;
 675         my_vis_info = NULL;
 676         spin_unlock_irqrestore(&vis_hash_lock, flags);
 677 }
 678
 679 /* schedule packets for (re)transmission */
 680 static void start_vis_timer(void)
 681 {
 682         queue_delayed_work(bat_event_workqueue, &vis_timer_wq,
 683                            (atomic_read(&vis_interval) * HZ) / 1000);
 684 }