net/decnet/dn_neigh.c

   1 /*
   2  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   3  *              operating system.  DECnet is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              DECnet Neighbour Functions (Adjacency Database and
   7  *                                                        On-Ethernet Cache)
   8  *
   9  * Author:      Steve Whitehouse <SteveW@ACM.org>
  10  *
  11  *
  12  * Changes:
  13  *     Steve Whitehouse     : Fixed router listing routine
  14  *     Steve Whitehouse     : Added error_report functions
  15  *     Steve Whitehouse     : Added default router detection
  16  *     Steve Whitehouse     : Hop counts in outgoing messages
  17  *     Steve Whitehouse     : Fixed src/dst in outgoing messages so
  18  *                            forwarding now stands a good chance of
  19  *                            working.
  20  *     Steve Whitehouse     : Fixed neighbour states (for now anyway).
  21  *     Steve Whitehouse     : Made error_report functions dummies. This
  22  *                            is not the right place to return skbs.
  23  *     Steve Whitehouse     : Convert to seq_file
  24  *
  25  */
  26
  27 #include <linux/net.h>
  28 #include <linux/module.h>
  29 #include <linux/socket.h>
  30 #include <linux/if_arp.h>
  31 #include <linux/slab.h>
  32 #include <linux/if_ether.h>
  33 #include <linux/init.h>
  34 #include <linux/proc_fs.h>
  35 #include <linux/string.h>
  36 #include <linux/netfilter_decnet.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/seq_file.h>
  39 #include <linux/rcupdate.h>
  40 #include <linux/jhash.h>
  41 #include <linux/atomic.h>
  42 #include <net/net_namespace.h>
  43 #include <net/neighbour.h>
  44 #include <net/dst.h>
  45 #include <net/flow.h>
  46 #include <net/dn.h>
  47 #include <net/dn_dev.h>
  48 #include <net/dn_neigh.h>
  49 #include <net/dn_route.h>
  50
  51 static int dn_neigh_construct(struct neighbour *);
  52 static void dn_neigh_error_report(struct neighbour *, struct sk_buff *);
  53 static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb);
  54
  55 /*
  56  * Operations for adding the link layer header.
  57  */
  58 static const struct neigh_ops dn_neigh_ops = {
  59         .family =               AF_DECnet,
  60         .error_report =         dn_neigh_error_report,
  61         .output =               dn_neigh_output,
  62         .connected_output =     dn_neigh_output,
  63 };
  64
  65 static u32 dn_neigh_hash(const void *pkey,
  66                          const struct net_device *dev,
  67                          __u32 *hash_rnd)
  68 {
  69         return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
  70 }
  71
  72 static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)
  73 {
  74         return neigh_key_eq16(neigh, pkey);
  75 }
  76
  77 struct neigh_table dn_neigh_table = {
  78         .family =                       PF_DECnet,
  79         .entry_size =                   NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
  80         .key_len =                      sizeof(__le16),
  81         .protocol =                     cpu_to_be16(ETH_P_DNA_RT),
  82         .hash =                         dn_neigh_hash,
  83         .key_eq =                       dn_key_eq,
  84         .constructor =                  dn_neigh_construct,
  85         .id =                           "dn_neigh_cache",
  86         .parms ={
  87                 .tbl =                  &dn_neigh_table,
  88                 .reachable_time =       30 * HZ,
  89                 .data = {
  90                         [NEIGH_VAR_MCAST_PROBES] = 0,
  91                         [NEIGH_VAR_UCAST_PROBES] = 0,
  92                         [NEIGH_VAR_APP_PROBES] = 0,
  93                         [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
  94                         [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
  95                         [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
  96                         [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
  97                         [NEIGH_VAR_QUEUE_LEN_BYTES] = 64*1024,
  98                         [NEIGH_VAR_PROXY_QLEN] = 0,
  99                         [NEIGH_VAR_ANYCAST_DELAY] = 0,
 100                         [NEIGH_VAR_PROXY_DELAY] = 0,
 101                         [NEIGH_VAR_LOCKTIME] = 1 * HZ,
 102                 },
 103         },
 104         .gc_interval =                  30 * HZ,
 105         .gc_thresh1 =                   128,
 106         .gc_thresh2 =                   512,
 107         .gc_thresh3 =                   1024,
 108 };
 109
 110 static int dn_neigh_construct(struct neighbour *neigh)
 111 {
 112         struct net_device *dev = neigh->dev;
 113         struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
 114         struct dn_dev *dn_db;
 115         struct neigh_parms *parms;
 116
 117         rcu_read_lock();
 118         dn_db = rcu_dereference(dev->dn_ptr);
 119         if (dn_db == NULL) {
 120                 rcu_read_unlock();
 121                 return -EINVAL;
 122         }
 123
 124         parms = dn_db->neigh_parms;
 125         if (!parms) {
 126                 rcu_read_unlock();
 127                 return -EINVAL;
 128         }
 129
 130         __neigh_parms_put(neigh->parms);
 131         neigh->parms = neigh_parms_clone(parms);
 132         rcu_read_unlock();
 133
 134         neigh->ops = &dn_neigh_ops;
 135         neigh->nud_state = NUD_NOARP;
 136         neigh->output = neigh->ops->connected_output;
 137
 138         if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 139                 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 140         else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 141                 dn_dn2eth(neigh->ha, dn->addr);
 142         else {
 143                 net_dbg_ratelimited("Trying to create neigh for hw %d\n",
 144                                     dev->type);
 145                 return -EINVAL;
 146         }
 147
 148         /*
 149          * Make an estimate of the remote block size by assuming that its
 150          * two less then the device mtu, which it true for ethernet (and
 151          * other things which support long format headers) since there is
 152          * an extra length field (of 16 bits) which isn't part of the
 153          * ethernet headers and which the DECnet specs won't admit is part
 154          * of the DECnet routing headers either.
 155          *
 156          * If we over estimate here its no big deal, the NSP negotiations
 157          * will prevent us from sending packets which are too large for the
 158          * remote node to handle. In any case this figure is normally updated
 159          * by a hello message in most cases.
 160          */
 161         dn->blksize = dev->mtu - 2;
 162
 163         return 0;
 164 }
 165
 166 static void dn_neigh_error_report(struct neighbour *neigh, struct sk_buff *skb)
 167 {
 168         printk(KERN_DEBUG "dn_neigh_error_report: called\n");
 169         kfree_skb(skb);
 170 }
 171
 172 static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb)
 173 {
 174         struct dst_entry *dst = skb_dst(skb);
 175         struct dn_route *rt = (struct dn_route *)dst;
 176         struct net_device *dev = neigh->dev;
 177         char mac_addr[ETH_ALEN];
 178         unsigned int seq;
 179         int err;
 180
 181         dn_dn2eth(mac_addr, rt->rt_local_src);
 182         do {
 183                 seq = read_seqbegin(&neigh->ha_lock);
 184                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
 185                                       neigh->ha, mac_addr, skb->len);
 186         } while (read_seqretry(&neigh->ha_lock, seq));
 187
 188         if (err >= 0)
 189                 err = dev_queue_xmit(skb);
 190         else {
 191                 kfree_skb(skb);
 192                 err = -EINVAL;
 193         }
 194         return err;
 195 }
 196
 197 static int dn_neigh_output_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
 198 {
 199         struct dst_entry *dst = skb_dst(skb);
 200         struct dn_route *rt = (struct dn_route *)dst;
 201         struct neighbour *neigh = rt->n;
 202
 203         return neigh->output(neigh, skb);
 204 }
 205
 206 /*
 207  * For talking to broadcast devices: Ethernet & PPP
 208  */
 209 static int dn_long_output(struct neighbour *neigh, struct sock *sk,
 210                           struct sk_buff *skb)
 211 {
 212         struct net_device *dev = neigh->dev;
 213         int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
 214         unsigned char *data;
 215         struct dn_long_packet *lp;
 216         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 217
 218
 219         if (skb_headroom(skb) < headroom) {
 220                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 221                 if (skb2 == NULL) {
 222                         net_crit_ratelimited("dn_long_output: no memory\n");
 223                         kfree_skb(skb);
 224                         return -ENOBUFS;
 225                 }
 226                 consume_skb(skb);
 227                 skb = skb2;
 228                 net_info_ratelimited("dn_long_output: Increasing headroom\n");
 229         }
 230
 231         data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
 232         lp = (struct dn_long_packet *)(data+3);
 233
 234         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 235         *(data + 2) = 1 | DN_RT_F_PF; /* Padding */
 236
 237         lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
 238         lp->d_area   = lp->d_subarea = 0;
 239         dn_dn2eth(lp->d_id, cb->dst);
 240         lp->s_area   = lp->s_subarea = 0;
 241         dn_dn2eth(lp->s_id, cb->src);
 242         lp->nl2      = 0;
 243         lp->visit_ct = cb->hops & 0x3f;
 244         lp->s_class  = 0;
 245         lp->pt       = 0;
 246
 247         skb_reset_network_header(skb);
 248
 249         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
 250                        &init_net, sk, skb, NULL, neigh->dev,
 251                        dn_neigh_output_packet);
 252 }
 253
 254 /*
 255  * For talking to pointopoint and multidrop devices: DDCMP and X.25
 256  */
 257 static int dn_short_output(struct neighbour *neigh, struct sock *sk,
 258                            struct sk_buff *skb)
 259 {
 260         struct net_device *dev = neigh->dev;
 261         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 262         struct dn_short_packet *sp;
 263         unsigned char *data;
 264         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 265
 266
 267         if (skb_headroom(skb) < headroom) {
 268                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 269                 if (skb2 == NULL) {
 270                         net_crit_ratelimited("dn_short_output: no memory\n");
 271                         kfree_skb(skb);
 272                         return -ENOBUFS;
 273                 }
 274                 consume_skb(skb);
 275                 skb = skb2;
 276                 net_info_ratelimited("dn_short_output: Increasing headroom\n");
 277         }
 278
 279         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 280         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 281         sp = (struct dn_short_packet *)(data+2);
 282
 283         sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 284         sp->dstnode    = cb->dst;
 285         sp->srcnode    = cb->src;
 286         sp->forward    = cb->hops & 0x3f;
 287
 288         skb_reset_network_header(skb);
 289
 290         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
 291                        &init_net, sk, skb, NULL, neigh->dev,
 292                        dn_neigh_output_packet);
 293 }
 294
 295 /*
 296  * For talking to DECnet phase III nodes
 297  * Phase 3 output is the same as short output, execpt that
 298  * it clears the area bits before transmission.
 299  */
 300 static int dn_phase3_output(struct neighbour *neigh, struct sock *sk,
 301                             struct sk_buff *skb)
 302 {
 303         struct net_device *dev = neigh->dev;
 304         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 305         struct dn_short_packet *sp;
 306         unsigned char *data;
 307         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 308
 309         if (skb_headroom(skb) < headroom) {
 310                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 311                 if (skb2 == NULL) {
 312                         net_crit_ratelimited("dn_phase3_output: no memory\n");
 313                         kfree_skb(skb);
 314                         return -ENOBUFS;
 315                 }
 316                 consume_skb(skb);
 317                 skb = skb2;
 318                 net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
 319         }
 320
 321         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 322         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 323         sp = (struct dn_short_packet *)(data + 2);
 324
 325         sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 326         sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
 327         sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
 328         sp->forward  = cb->hops & 0x3f;
 329
 330         skb_reset_network_header(skb);
 331
 332         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
 333                        &init_net, sk, skb, NULL, neigh->dev,
 334                        dn_neigh_output_packet);
 335 }
 336
 337 int dn_to_neigh_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 338 {
 339         struct dst_entry *dst = skb_dst(skb);
 340         struct dn_route *rt = (struct dn_route *) dst;
 341         struct neighbour *neigh = rt->n;
 342         struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
 343         struct dn_dev *dn_db;
 344         bool use_long;
 345
 346         rcu_read_lock();
 347         dn_db = rcu_dereference(neigh->dev->dn_ptr);
 348         if (dn_db == NULL) {
 349                 rcu_read_unlock();
 350                 return -EINVAL;
 351         }
 352         use_long = dn_db->use_long;
 353         rcu_read_unlock();
 354
 355         if (dn->flags & DN_NDFLAG_P3)
 356                 return dn_phase3_output(neigh, sk, skb);
 357         if (use_long)
 358                 return dn_long_output(neigh, sk, skb);
 359         else
 360                 return dn_short_output(neigh, sk, skb);
 361 }
 362
 363 /*
 364  * Unfortunately, the neighbour code uses the device in its hash
 365  * function, so we don't get any advantage from it. This function
 366  * basically does a neigh_lookup(), but without comparing the device
 367  * field. This is required for the On-Ethernet cache
 368  */
 369
 370 /*
 371  * Pointopoint link receives a hello message
 372  */
 373 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 374 {
 375         kfree_skb(skb);
 376 }
 377
 378 /*
 379  * Ethernet router hello message received
 380  */
 381 int dn_neigh_router_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
 382 {
 383         struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 384
 385         struct neighbour *neigh;
 386         struct dn_neigh *dn;
 387         struct dn_dev *dn_db;
 388         __le16 src;
 389
 390         src = dn_eth2dn(msg->id);
 391
 392         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 393
 394         dn = container_of(neigh, struct dn_neigh, n);
 395
 396         if (neigh) {
 397                 write_lock(&neigh->lock);
 398
 399                 neigh->used = jiffies;
 400                 dn_db = rcu_dereference(neigh->dev->dn_ptr);
 401
 402                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 403                         neigh->updated = jiffies;
 404
 405                         if (neigh->dev->type == ARPHRD_ETHER)
 406                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 407
 408                         dn->blksize  = le16_to_cpu(msg->blksize);
 409                         dn->priority = msg->priority;
 410
 411                         dn->flags &= ~DN_NDFLAG_P3;
 412
 413                         switch (msg->iinfo & DN_RT_INFO_TYPE) {
 414                         case DN_RT_INFO_L1RT:
 415                                 dn->flags &=~DN_NDFLAG_R2;
 416                                 dn->flags |= DN_NDFLAG_R1;
 417                                 break;
 418                         case DN_RT_INFO_L2RT:
 419                                 dn->flags |= DN_NDFLAG_R2;
 420                         }
 421                 }
 422
 423                 /* Only use routers in our area */
 424                 if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
 425                         if (!dn_db->router) {
 426                                 dn_db->router = neigh_clone(neigh);
 427                         } else {
 428                                 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 429                                         neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 430                         }
 431                 }
 432                 write_unlock(&neigh->lock);
 433                 neigh_release(neigh);
 434         }
 435
 436         kfree_skb(skb);
 437         return 0;
 438 }
 439
 440 /*
 441  * Endnode hello message received
 442  */
 443 int dn_neigh_endnode_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
 444 {
 445         struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 446         struct neighbour *neigh;
 447         struct dn_neigh *dn;
 448         __le16 src;
 449
 450         src = dn_eth2dn(msg->id);
 451
 452         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 453
 454         dn = container_of(neigh, struct dn_neigh, n);
 455
 456         if (neigh) {
 457                 write_lock(&neigh->lock);
 458
 459                 neigh->used = jiffies;
 460
 461                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 462                         neigh->updated = jiffies;
 463
 464                         if (neigh->dev->type == ARPHRD_ETHER)
 465                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 466                         dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 467                         dn->blksize  = le16_to_cpu(msg->blksize);
 468                         dn->priority = 0;
 469                 }
 470
 471                 write_unlock(&neigh->lock);
 472                 neigh_release(neigh);
 473         }
 474
 475         kfree_skb(skb);
 476         return 0;
 477 }
 478
 479 static char *dn_find_slot(char *base, int max, int priority)
 480 {
 481         int i;
 482         unsigned char *min = NULL;
 483
 484         base += 6; /* skip first id */
 485
 486         for(i = 0; i < max; i++) {
 487                 if (!min || (*base < *min))
 488                         min = base;
 489                 base += 7; /* find next priority */
 490         }
 491
 492         if (!min)
 493                 return NULL;
 494
 495         return (*min < priority) ? (min - 6) : NULL;
 496 }
 497
 498 struct elist_cb_state {
 499         struct net_device *dev;
 500         unsigned char *ptr;
 501         unsigned char *rs;
 502         int t, n;
 503 };
 504
 505 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 506 {
 507         struct elist_cb_state *s = _info;
 508         struct dn_neigh *dn;
 509
 510         if (neigh->dev != s->dev)
 511                 return;
 512
 513         dn = container_of(neigh, struct dn_neigh, n);
 514         if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 515                 return;
 516
 517         if (s->t == s->n)
 518                 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 519         else
 520                 s->t++;
 521         if (s->rs == NULL)
 522                 return;
 523
 524         dn_dn2eth(s->rs, dn->addr);
 525         s->rs += 6;
 526         *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 527         *(s->rs) |= dn->priority;
 528         s->rs++;
 529 }
 530
 531 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 532 {
 533         struct elist_cb_state state;
 534
 535         state.dev = dev;
 536         state.t = 0;
 537         state.n = n;
 538         state.ptr = ptr;
 539         state.rs = ptr;
 540
 541         neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 542
 543         return state.t;
 544 }
 545
 546
 547 #ifdef CONFIG_PROC_FS
 548
 549 static inline void dn_neigh_format_entry(struct seq_file *seq,
 550                                          struct neighbour *n)
 551 {
 552         struct dn_neigh *dn = container_of(n, struct dn_neigh, n);
 553         char buf[DN_ASCBUF_LEN];
 554
 555         read_lock(&n->lock);
 556         seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 557                    dn_addr2asc(le16_to_cpu(dn->addr), buf),
 558                    (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 559                    (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 560                    (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 561                    dn->n.nud_state,
 562                    refcount_read(&dn->n.refcnt),
 563                    dn->blksize,
 564                    (dn->n.dev) ? dn->n.dev->name : "?");
 565         read_unlock(&n->lock);
 566 }
 567
 568 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 569 {
 570         if (v == SEQ_START_TOKEN) {
 571                 seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 572         } else {
 573                 dn_neigh_format_entry(seq, v);
 574         }
 575
 576         return 0;
 577 }
 578
 579 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 580 {
 581         return neigh_seq_start(seq, pos, &dn_neigh_table,
 582                                NEIGH_SEQ_NEIGH_ONLY);
 583 }
 584
 585 static const struct seq_operations dn_neigh_seq_ops = {
 586         .start = dn_neigh_seq_start,
 587         .next  = neigh_seq_next,
 588         .stop  = neigh_seq_stop,
 589         .show  = dn_neigh_seq_show,
 590 };
 591
 592 static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 593 {
 594         return seq_open_net(inode, file, &dn_neigh_seq_ops,
 595                             sizeof(struct neigh_seq_state));
 596 }
 597
 598 static const struct file_operations dn_neigh_seq_fops = {
 599         .owner          = THIS_MODULE,
 600         .open           = dn_neigh_seq_open,
 601         .read           = seq_read,
 602         .llseek         = seq_lseek,
 603         .release        = seq_release_net,
 604 };
 605
 606 #endif
 607
 608 void __init dn_neigh_init(void)
 609 {
 610         neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
 611         proc_create("decnet_neigh", S_IRUGO, init_net.proc_net,
 612                     &dn_neigh_seq_fops);
 613 }
 614
 615 void __exit dn_neigh_cleanup(void)
 616 {
 617         remove_proc_entry("decnet_neigh", init_net.proc_net);
 618         neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
 619 }