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_long_error_report(struct neighbour *, struct sk_buff *);
  53 static void dn_short_error_report(struct neighbour *, struct sk_buff *);
  54 static int dn_long_output(struct neighbour *, struct sk_buff *);
  55 static int dn_short_output(struct neighbour *, struct sk_buff *);
  56 static int dn_phase3_output(struct neighbour *, struct sk_buff *);
  57
  58
  59 /*
  60  * For talking to broadcast devices: Ethernet & PPP
  61  */
  62 static const struct neigh_ops dn_long_ops = {
  63         .family =               AF_DECnet,
  64         .error_report =         dn_long_error_report,
  65         .output =               dn_long_output,
  66         .connected_output =     dn_long_output,
  67 };
  68
  69 /*
  70  * For talking to pointopoint and multidrop devices: DDCMP and X.25
  71  */
  72 static const struct neigh_ops dn_short_ops = {
  73         .family =               AF_DECnet,
  74         .error_report =         dn_short_error_report,
  75         .output =               dn_short_output,
  76         .connected_output =     dn_short_output,
  77 };
  78
  79 /*
  80  * For talking to DECnet phase III nodes
  81  */
  82 static const struct neigh_ops dn_phase3_ops = {
  83         .family =               AF_DECnet,
  84         .error_report =         dn_short_error_report, /* Can use short version here */
  85         .output =               dn_phase3_output,
  86         .connected_output =     dn_phase3_output,
  87 };
  88
  89 static u32 dn_neigh_hash(const void *pkey,
  90                          const struct net_device *dev,
  91                          __u32 *hash_rnd)
  92 {
  93         return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
  94 }
  95
  96 struct neigh_table dn_neigh_table = {
  97         .family =                       PF_DECnet,
  98         .entry_size =                   NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
  99         .key_len =                      sizeof(__le16),
 100         .protocol =                     cpu_to_be16(ETH_P_DNA_RT),
 101         .hash =                         dn_neigh_hash,
 102         .constructor =                  dn_neigh_construct,
 103         .id =                           "dn_neigh_cache",
 104         .parms ={
 105                 .tbl =                  &dn_neigh_table,
 106                 .reachable_time =       30 * HZ,
 107                 .data = {
 108                         [NEIGH_VAR_MCAST_PROBES] = 0,
 109                         [NEIGH_VAR_UCAST_PROBES] = 0,
 110                         [NEIGH_VAR_APP_PROBES] = 0,
 111                         [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
 112                         [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
 113                         [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
 114                         [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
 115                         [NEIGH_VAR_QUEUE_LEN_BYTES] = 64*1024,
 116                         [NEIGH_VAR_PROXY_QLEN] = 0,
 117                         [NEIGH_VAR_ANYCAST_DELAY] = 0,
 118                         [NEIGH_VAR_PROXY_DELAY] = 0,
 119                         [NEIGH_VAR_LOCKTIME] = 1 * HZ,
 120                 },
 121         },
 122         .gc_interval =                  30 * HZ,
 123         .gc_thresh1 =                   128,
 124         .gc_thresh2 =                   512,
 125         .gc_thresh3 =                   1024,
 126 };
 127
 128 static int dn_neigh_construct(struct neighbour *neigh)
 129 {
 130         struct net_device *dev = neigh->dev;
 131         struct dn_neigh *dn = (struct dn_neigh *)neigh;
 132         struct dn_dev *dn_db;
 133         struct neigh_parms *parms;
 134
 135         rcu_read_lock();
 136         dn_db = rcu_dereference(dev->dn_ptr);
 137         if (dn_db == NULL) {
 138                 rcu_read_unlock();
 139                 return -EINVAL;
 140         }
 141
 142         parms = dn_db->neigh_parms;
 143         if (!parms) {
 144                 rcu_read_unlock();
 145                 return -EINVAL;
 146         }
 147
 148         __neigh_parms_put(neigh->parms);
 149         neigh->parms = neigh_parms_clone(parms);
 150
 151         if (dn_db->use_long)
 152                 neigh->ops = &dn_long_ops;
 153         else
 154                 neigh->ops = &dn_short_ops;
 155         rcu_read_unlock();
 156
 157         if (dn->flags & DN_NDFLAG_P3)
 158                 neigh->ops = &dn_phase3_ops;
 159
 160         neigh->nud_state = NUD_NOARP;
 161         neigh->output = neigh->ops->connected_output;
 162
 163         if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 164                 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 165         else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 166                 dn_dn2eth(neigh->ha, dn->addr);
 167         else {
 168                 net_dbg_ratelimited("Trying to create neigh for hw %d\n",
 169                                     dev->type);
 170                 return -EINVAL;
 171         }
 172
 173         /*
 174          * Make an estimate of the remote block size by assuming that its
 175          * two less then the device mtu, which it true for ethernet (and
 176          * other things which support long format headers) since there is
 177          * an extra length field (of 16 bits) which isn't part of the
 178          * ethernet headers and which the DECnet specs won't admit is part
 179          * of the DECnet routing headers either.
 180          *
 181          * If we over estimate here its no big deal, the NSP negotiations
 182          * will prevent us from sending packets which are too large for the
 183          * remote node to handle. In any case this figure is normally updated
 184          * by a hello message in most cases.
 185          */
 186         dn->blksize = dev->mtu - 2;
 187
 188         return 0;
 189 }
 190
 191 static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
 192 {
 193         printk(KERN_DEBUG "dn_long_error_report: called\n");
 194         kfree_skb(skb);
 195 }
 196
 197
 198 static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
 199 {
 200         printk(KERN_DEBUG "dn_short_error_report: called\n");
 201         kfree_skb(skb);
 202 }
 203
 204 static int dn_neigh_output_packet(struct sk_buff *skb)
 205 {
 206         struct dst_entry *dst = skb_dst(skb);
 207         struct dn_route *rt = (struct dn_route *)dst;
 208         struct neighbour *neigh = rt->n;
 209         struct net_device *dev = neigh->dev;
 210         char mac_addr[ETH_ALEN];
 211         unsigned int seq;
 212         int err;
 213
 214         dn_dn2eth(mac_addr, rt->rt_local_src);
 215         do {
 216                 seq = read_seqbegin(&neigh->ha_lock);
 217                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
 218                                       neigh->ha, mac_addr, skb->len);
 219         } while (read_seqretry(&neigh->ha_lock, seq));
 220
 221         if (err >= 0)
 222                 err = dev_queue_xmit(skb);
 223         else {
 224                 kfree_skb(skb);
 225                 err = -EINVAL;
 226         }
 227         return err;
 228 }
 229
 230 static int dn_long_output(struct neighbour *neigh, struct sk_buff *skb)
 231 {
 232         struct net_device *dev = neigh->dev;
 233         int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
 234         unsigned char *data;
 235         struct dn_long_packet *lp;
 236         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 237
 238
 239         if (skb_headroom(skb) < headroom) {
 240                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 241                 if (skb2 == NULL) {
 242                         net_crit_ratelimited("dn_long_output: no memory\n");
 243                         kfree_skb(skb);
 244                         return -ENOBUFS;
 245                 }
 246                 consume_skb(skb);
 247                 skb = skb2;
 248                 net_info_ratelimited("dn_long_output: Increasing headroom\n");
 249         }
 250
 251         data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
 252         lp = (struct dn_long_packet *)(data+3);
 253
 254         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 255         *(data + 2) = 1 | DN_RT_F_PF; /* Padding */
 256
 257         lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
 258         lp->d_area   = lp->d_subarea = 0;
 259         dn_dn2eth(lp->d_id, cb->dst);
 260         lp->s_area   = lp->s_subarea = 0;
 261         dn_dn2eth(lp->s_id, cb->src);
 262         lp->nl2      = 0;
 263         lp->visit_ct = cb->hops & 0x3f;
 264         lp->s_class  = 0;
 265         lp->pt       = 0;
 266
 267         skb_reset_network_header(skb);
 268
 269         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 270                        neigh->dev, dn_neigh_output_packet);
 271 }
 272
 273 static int dn_short_output(struct neighbour *neigh, struct sk_buff *skb)
 274 {
 275         struct net_device *dev = neigh->dev;
 276         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 277         struct dn_short_packet *sp;
 278         unsigned char *data;
 279         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 280
 281
 282         if (skb_headroom(skb) < headroom) {
 283                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 284                 if (skb2 == NULL) {
 285                         net_crit_ratelimited("dn_short_output: no memory\n");
 286                         kfree_skb(skb);
 287                         return -ENOBUFS;
 288                 }
 289                 consume_skb(skb);
 290                 skb = skb2;
 291                 net_info_ratelimited("dn_short_output: Increasing headroom\n");
 292         }
 293
 294         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 295         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 296         sp = (struct dn_short_packet *)(data+2);
 297
 298         sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 299         sp->dstnode    = cb->dst;
 300         sp->srcnode    = cb->src;
 301         sp->forward    = cb->hops & 0x3f;
 302
 303         skb_reset_network_header(skb);
 304
 305         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 306                        neigh->dev, dn_neigh_output_packet);
 307 }
 308
 309 /*
 310  * Phase 3 output is the same is short output, execpt that
 311  * it clears the area bits before transmission.
 312  */
 313 static int dn_phase3_output(struct neighbour *neigh, struct sk_buff *skb)
 314 {
 315         struct net_device *dev = neigh->dev;
 316         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 317         struct dn_short_packet *sp;
 318         unsigned char *data;
 319         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 320
 321         if (skb_headroom(skb) < headroom) {
 322                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 323                 if (skb2 == NULL) {
 324                         net_crit_ratelimited("dn_phase3_output: no memory\n");
 325                         kfree_skb(skb);
 326                         return -ENOBUFS;
 327                 }
 328                 consume_skb(skb);
 329                 skb = skb2;
 330                 net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
 331         }
 332
 333         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 334         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 335         sp = (struct dn_short_packet *)(data + 2);
 336
 337         sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 338         sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
 339         sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
 340         sp->forward  = cb->hops & 0x3f;
 341
 342         skb_reset_network_header(skb);
 343
 344         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 345                        neigh->dev, dn_neigh_output_packet);
 346 }
 347
 348 /*
 349  * Unfortunately, the neighbour code uses the device in its hash
 350  * function, so we don't get any advantage from it. This function
 351  * basically does a neigh_lookup(), but without comparing the device
 352  * field. This is required for the On-Ethernet cache
 353  */
 354
 355 /*
 356  * Pointopoint link receives a hello message
 357  */
 358 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 359 {
 360         kfree_skb(skb);
 361 }
 362
 363 /*
 364  * Ethernet router hello message received
 365  */
 366 int dn_neigh_router_hello(struct sk_buff *skb)
 367 {
 368         struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 369
 370         struct neighbour *neigh;
 371         struct dn_neigh *dn;
 372         struct dn_dev *dn_db;
 373         __le16 src;
 374
 375         src = dn_eth2dn(msg->id);
 376
 377         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 378
 379         dn = (struct dn_neigh *)neigh;
 380
 381         if (neigh) {
 382                 write_lock(&neigh->lock);
 383
 384                 neigh->used = jiffies;
 385                 dn_db = rcu_dereference(neigh->dev->dn_ptr);
 386
 387                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 388                         neigh->updated = jiffies;
 389
 390                         if (neigh->dev->type == ARPHRD_ETHER)
 391                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 392
 393                         dn->blksize  = le16_to_cpu(msg->blksize);
 394                         dn->priority = msg->priority;
 395
 396                         dn->flags &= ~DN_NDFLAG_P3;
 397
 398                         switch (msg->iinfo & DN_RT_INFO_TYPE) {
 399                         case DN_RT_INFO_L1RT:
 400                                 dn->flags &=~DN_NDFLAG_R2;
 401                                 dn->flags |= DN_NDFLAG_R1;
 402                                 break;
 403                         case DN_RT_INFO_L2RT:
 404                                 dn->flags |= DN_NDFLAG_R2;
 405                         }
 406                 }
 407
 408                 /* Only use routers in our area */
 409                 if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
 410                         if (!dn_db->router) {
 411                                 dn_db->router = neigh_clone(neigh);
 412                         } else {
 413                                 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 414                                         neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 415                         }
 416                 }
 417                 write_unlock(&neigh->lock);
 418                 neigh_release(neigh);
 419         }
 420
 421         kfree_skb(skb);
 422         return 0;
 423 }
 424
 425 /*
 426  * Endnode hello message received
 427  */
 428 int dn_neigh_endnode_hello(struct sk_buff *skb)
 429 {
 430         struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 431         struct neighbour *neigh;
 432         struct dn_neigh *dn;
 433         __le16 src;
 434
 435         src = dn_eth2dn(msg->id);
 436
 437         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 438
 439         dn = (struct dn_neigh *)neigh;
 440
 441         if (neigh) {
 442                 write_lock(&neigh->lock);
 443
 444                 neigh->used = jiffies;
 445
 446                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 447                         neigh->updated = jiffies;
 448
 449                         if (neigh->dev->type == ARPHRD_ETHER)
 450                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 451                         dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 452                         dn->blksize  = le16_to_cpu(msg->blksize);
 453                         dn->priority = 0;
 454                 }
 455
 456                 write_unlock(&neigh->lock);
 457                 neigh_release(neigh);
 458         }
 459
 460         kfree_skb(skb);
 461         return 0;
 462 }
 463
 464 static char *dn_find_slot(char *base, int max, int priority)
 465 {
 466         int i;
 467         unsigned char *min = NULL;
 468
 469         base += 6; /* skip first id */
 470
 471         for(i = 0; i < max; i++) {
 472                 if (!min || (*base < *min))
 473                         min = base;
 474                 base += 7; /* find next priority */
 475         }
 476
 477         if (!min)
 478                 return NULL;
 479
 480         return (*min < priority) ? (min - 6) : NULL;
 481 }
 482
 483 struct elist_cb_state {
 484         struct net_device *dev;
 485         unsigned char *ptr;
 486         unsigned char *rs;
 487         int t, n;
 488 };
 489
 490 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 491 {
 492         struct elist_cb_state *s = _info;
 493         struct dn_neigh *dn;
 494
 495         if (neigh->dev != s->dev)
 496                 return;
 497
 498         dn = (struct dn_neigh *) neigh;
 499         if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 500                 return;
 501
 502         if (s->t == s->n)
 503                 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 504         else
 505                 s->t++;
 506         if (s->rs == NULL)
 507                 return;
 508
 509         dn_dn2eth(s->rs, dn->addr);
 510         s->rs += 6;
 511         *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 512         *(s->rs) |= dn->priority;
 513         s->rs++;
 514 }
 515
 516 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 517 {
 518         struct elist_cb_state state;
 519
 520         state.dev = dev;
 521         state.t = 0;
 522         state.n = n;
 523         state.ptr = ptr;
 524         state.rs = ptr;
 525
 526         neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 527
 528         return state.t;
 529 }
 530
 531
 532 #ifdef CONFIG_PROC_FS
 533
 534 static inline void dn_neigh_format_entry(struct seq_file *seq,
 535                                          struct neighbour *n)
 536 {
 537         struct dn_neigh *dn = (struct dn_neigh *) n;
 538         char buf[DN_ASCBUF_LEN];
 539
 540         read_lock(&n->lock);
 541         seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 542                    dn_addr2asc(le16_to_cpu(dn->addr), buf),
 543                    (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 544                    (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 545                    (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 546                    dn->n.nud_state,
 547                    atomic_read(&dn->n.refcnt),
 548                    dn->blksize,
 549                    (dn->n.dev) ? dn->n.dev->name : "?");
 550         read_unlock(&n->lock);
 551 }
 552
 553 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 554 {
 555         if (v == SEQ_START_TOKEN) {
 556                 seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 557         } else {
 558                 dn_neigh_format_entry(seq, v);
 559         }
 560
 561         return 0;
 562 }
 563
 564 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 565 {
 566         return neigh_seq_start(seq, pos, &dn_neigh_table,
 567                                NEIGH_SEQ_NEIGH_ONLY);
 568 }
 569
 570 static const struct seq_operations dn_neigh_seq_ops = {
 571         .start = dn_neigh_seq_start,
 572         .next  = neigh_seq_next,
 573         .stop  = neigh_seq_stop,
 574         .show  = dn_neigh_seq_show,
 575 };
 576
 577 static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 578 {
 579         return seq_open_net(inode, file, &dn_neigh_seq_ops,
 580                             sizeof(struct neigh_seq_state));
 581 }
 582
 583 static const struct file_operations dn_neigh_seq_fops = {
 584         .owner          = THIS_MODULE,
 585         .open           = dn_neigh_seq_open,
 586         .read           = seq_read,
 587         .llseek         = seq_lseek,
 588         .release        = seq_release_net,
 589 };
 590
 591 #endif
 592
 593 void __init dn_neigh_init(void)
 594 {
 595         neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
 596         proc_create("decnet_neigh", S_IRUGO, init_net.proc_net,
 597                     &dn_neigh_seq_fops);
 598 }
 599
 600 void __exit dn_neigh_cleanup(void)
 601 {
 602         remove_proc_entry("decnet_neigh", init_net.proc_net);
 603         neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
 604 }