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 static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)
  97 {
  98         return neigh_key_eq16(neigh, pkey);
  99 }
 100
 101 struct neigh_table dn_neigh_table = {
 102         .family =                       PF_DECnet,
 103         .entry_size =                   NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
 104         .key_len =                      sizeof(__le16),
 105         .protocol =                     cpu_to_be16(ETH_P_DNA_RT),
 106         .hash =                         dn_neigh_hash,
 107         .key_eq =                       dn_key_eq,
 108         .constructor =                  dn_neigh_construct,
 109         .id =                           "dn_neigh_cache",
 110         .parms ={
 111                 .tbl =                  &dn_neigh_table,
 112                 .reachable_time =       30 * HZ,
 113                 .data = {
 114                         [NEIGH_VAR_MCAST_PROBES] = 0,
 115                         [NEIGH_VAR_UCAST_PROBES] = 0,
 116                         [NEIGH_VAR_APP_PROBES] = 0,
 117                         [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
 118                         [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
 119                         [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
 120                         [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
 121                         [NEIGH_VAR_QUEUE_LEN_BYTES] = 64*1024,
 122                         [NEIGH_VAR_PROXY_QLEN] = 0,
 123                         [NEIGH_VAR_ANYCAST_DELAY] = 0,
 124                         [NEIGH_VAR_PROXY_DELAY] = 0,
 125                         [NEIGH_VAR_LOCKTIME] = 1 * HZ,
 126                 },
 127         },
 128         .gc_interval =                  30 * HZ,
 129         .gc_thresh1 =                   128,
 130         .gc_thresh2 =                   512,
 131         .gc_thresh3 =                   1024,
 132 };
 133
 134 static int dn_neigh_construct(struct neighbour *neigh)
 135 {
 136         struct net_device *dev = neigh->dev;
 137         struct dn_neigh *dn = (struct dn_neigh *)neigh;
 138         struct dn_dev *dn_db;
 139         struct neigh_parms *parms;
 140
 141         rcu_read_lock();
 142         dn_db = rcu_dereference(dev->dn_ptr);
 143         if (dn_db == NULL) {
 144                 rcu_read_unlock();
 145                 return -EINVAL;
 146         }
 147
 148         parms = dn_db->neigh_parms;
 149         if (!parms) {
 150                 rcu_read_unlock();
 151                 return -EINVAL;
 152         }
 153
 154         __neigh_parms_put(neigh->parms);
 155         neigh->parms = neigh_parms_clone(parms);
 156
 157         if (dn_db->use_long)
 158                 neigh->ops = &dn_long_ops;
 159         else
 160                 neigh->ops = &dn_short_ops;
 161         rcu_read_unlock();
 162
 163         if (dn->flags & DN_NDFLAG_P3)
 164                 neigh->ops = &dn_phase3_ops;
 165
 166         neigh->nud_state = NUD_NOARP;
 167         neigh->output = neigh->ops->connected_output;
 168
 169         if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 170                 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 171         else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 172                 dn_dn2eth(neigh->ha, dn->addr);
 173         else {
 174                 net_dbg_ratelimited("Trying to create neigh for hw %d\n",
 175                                     dev->type);
 176                 return -EINVAL;
 177         }
 178
 179         /*
 180          * Make an estimate of the remote block size by assuming that its
 181          * two less then the device mtu, which it true for ethernet (and
 182          * other things which support long format headers) since there is
 183          * an extra length field (of 16 bits) which isn't part of the
 184          * ethernet headers and which the DECnet specs won't admit is part
 185          * of the DECnet routing headers either.
 186          *
 187          * If we over estimate here its no big deal, the NSP negotiations
 188          * will prevent us from sending packets which are too large for the
 189          * remote node to handle. In any case this figure is normally updated
 190          * by a hello message in most cases.
 191          */
 192         dn->blksize = dev->mtu - 2;
 193
 194         return 0;
 195 }
 196
 197 static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
 198 {
 199         printk(KERN_DEBUG "dn_long_error_report: called\n");
 200         kfree_skb(skb);
 201 }
 202
 203
 204 static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
 205 {
 206         printk(KERN_DEBUG "dn_short_error_report: called\n");
 207         kfree_skb(skb);
 208 }
 209
 210 static int dn_neigh_output_packet(struct sk_buff *skb)
 211 {
 212         struct dst_entry *dst = skb_dst(skb);
 213         struct dn_route *rt = (struct dn_route *)dst;
 214         struct neighbour *neigh = rt->n;
 215         struct net_device *dev = neigh->dev;
 216         char mac_addr[ETH_ALEN];
 217         unsigned int seq;
 218         int err;
 219
 220         dn_dn2eth(mac_addr, rt->rt_local_src);
 221         do {
 222                 seq = read_seqbegin(&neigh->ha_lock);
 223                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
 224                                       neigh->ha, mac_addr, skb->len);
 225         } while (read_seqretry(&neigh->ha_lock, seq));
 226
 227         if (err >= 0)
 228                 err = dev_queue_xmit(skb);
 229         else {
 230                 kfree_skb(skb);
 231                 err = -EINVAL;
 232         }
 233         return err;
 234 }
 235
 236 static int dn_long_output(struct neighbour *neigh, struct sk_buff *skb)
 237 {
 238         struct net_device *dev = neigh->dev;
 239         int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
 240         unsigned char *data;
 241         struct dn_long_packet *lp;
 242         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 243
 244
 245         if (skb_headroom(skb) < headroom) {
 246                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 247                 if (skb2 == NULL) {
 248                         net_crit_ratelimited("dn_long_output: no memory\n");
 249                         kfree_skb(skb);
 250                         return -ENOBUFS;
 251                 }
 252                 consume_skb(skb);
 253                 skb = skb2;
 254                 net_info_ratelimited("dn_long_output: Increasing headroom\n");
 255         }
 256
 257         data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
 258         lp = (struct dn_long_packet *)(data+3);
 259
 260         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 261         *(data + 2) = 1 | DN_RT_F_PF; /* Padding */
 262
 263         lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
 264         lp->d_area   = lp->d_subarea = 0;
 265         dn_dn2eth(lp->d_id, cb->dst);
 266         lp->s_area   = lp->s_subarea = 0;
 267         dn_dn2eth(lp->s_id, cb->src);
 268         lp->nl2      = 0;
 269         lp->visit_ct = cb->hops & 0x3f;
 270         lp->s_class  = 0;
 271         lp->pt       = 0;
 272
 273         skb_reset_network_header(skb);
 274
 275         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 276                        neigh->dev, dn_neigh_output_packet);
 277 }
 278
 279 static int dn_short_output(struct neighbour *neigh, struct sk_buff *skb)
 280 {
 281         struct net_device *dev = neigh->dev;
 282         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 283         struct dn_short_packet *sp;
 284         unsigned char *data;
 285         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 286
 287
 288         if (skb_headroom(skb) < headroom) {
 289                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 290                 if (skb2 == NULL) {
 291                         net_crit_ratelimited("dn_short_output: no memory\n");
 292                         kfree_skb(skb);
 293                         return -ENOBUFS;
 294                 }
 295                 consume_skb(skb);
 296                 skb = skb2;
 297                 net_info_ratelimited("dn_short_output: Increasing headroom\n");
 298         }
 299
 300         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 301         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 302         sp = (struct dn_short_packet *)(data+2);
 303
 304         sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 305         sp->dstnode    = cb->dst;
 306         sp->srcnode    = cb->src;
 307         sp->forward    = cb->hops & 0x3f;
 308
 309         skb_reset_network_header(skb);
 310
 311         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 312                        neigh->dev, dn_neigh_output_packet);
 313 }
 314
 315 /*
 316  * Phase 3 output is the same is short output, execpt that
 317  * it clears the area bits before transmission.
 318  */
 319 static int dn_phase3_output(struct neighbour *neigh, struct sk_buff *skb)
 320 {
 321         struct net_device *dev = neigh->dev;
 322         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 323         struct dn_short_packet *sp;
 324         unsigned char *data;
 325         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 326
 327         if (skb_headroom(skb) < headroom) {
 328                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 329                 if (skb2 == NULL) {
 330                         net_crit_ratelimited("dn_phase3_output: no memory\n");
 331                         kfree_skb(skb);
 332                         return -ENOBUFS;
 333                 }
 334                 consume_skb(skb);
 335                 skb = skb2;
 336                 net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
 337         }
 338
 339         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 340         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 341         sp = (struct dn_short_packet *)(data + 2);
 342
 343         sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 344         sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
 345         sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
 346         sp->forward  = cb->hops & 0x3f;
 347
 348         skb_reset_network_header(skb);
 349
 350         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 351                        neigh->dev, dn_neigh_output_packet);
 352 }
 353
 354 /*
 355  * Unfortunately, the neighbour code uses the device in its hash
 356  * function, so we don't get any advantage from it. This function
 357  * basically does a neigh_lookup(), but without comparing the device
 358  * field. This is required for the On-Ethernet cache
 359  */
 360
 361 /*
 362  * Pointopoint link receives a hello message
 363  */
 364 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 365 {
 366         kfree_skb(skb);
 367 }
 368
 369 /*
 370  * Ethernet router hello message received
 371  */
 372 int dn_neigh_router_hello(struct sk_buff *skb)
 373 {
 374         struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 375
 376         struct neighbour *neigh;
 377         struct dn_neigh *dn;
 378         struct dn_dev *dn_db;
 379         __le16 src;
 380
 381         src = dn_eth2dn(msg->id);
 382
 383         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 384
 385         dn = (struct dn_neigh *)neigh;
 386
 387         if (neigh) {
 388                 write_lock(&neigh->lock);
 389
 390                 neigh->used = jiffies;
 391                 dn_db = rcu_dereference(neigh->dev->dn_ptr);
 392
 393                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 394                         neigh->updated = jiffies;
 395
 396                         if (neigh->dev->type == ARPHRD_ETHER)
 397                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 398
 399                         dn->blksize  = le16_to_cpu(msg->blksize);
 400                         dn->priority = msg->priority;
 401
 402                         dn->flags &= ~DN_NDFLAG_P3;
 403
 404                         switch (msg->iinfo & DN_RT_INFO_TYPE) {
 405                         case DN_RT_INFO_L1RT:
 406                                 dn->flags &=~DN_NDFLAG_R2;
 407                                 dn->flags |= DN_NDFLAG_R1;
 408                                 break;
 409                         case DN_RT_INFO_L2RT:
 410                                 dn->flags |= DN_NDFLAG_R2;
 411                         }
 412                 }
 413
 414                 /* Only use routers in our area */
 415                 if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
 416                         if (!dn_db->router) {
 417                                 dn_db->router = neigh_clone(neigh);
 418                         } else {
 419                                 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 420                                         neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 421                         }
 422                 }
 423                 write_unlock(&neigh->lock);
 424                 neigh_release(neigh);
 425         }
 426
 427         kfree_skb(skb);
 428         return 0;
 429 }
 430
 431 /*
 432  * Endnode hello message received
 433  */
 434 int dn_neigh_endnode_hello(struct sk_buff *skb)
 435 {
 436         struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 437         struct neighbour *neigh;
 438         struct dn_neigh *dn;
 439         __le16 src;
 440
 441         src = dn_eth2dn(msg->id);
 442
 443         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 444
 445         dn = (struct dn_neigh *)neigh;
 446
 447         if (neigh) {
 448                 write_lock(&neigh->lock);
 449
 450                 neigh->used = jiffies;
 451
 452                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 453                         neigh->updated = jiffies;
 454
 455                         if (neigh->dev->type == ARPHRD_ETHER)
 456                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 457                         dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 458                         dn->blksize  = le16_to_cpu(msg->blksize);
 459                         dn->priority = 0;
 460                 }
 461
 462                 write_unlock(&neigh->lock);
 463                 neigh_release(neigh);
 464         }
 465
 466         kfree_skb(skb);
 467         return 0;
 468 }
 469
 470 static char *dn_find_slot(char *base, int max, int priority)
 471 {
 472         int i;
 473         unsigned char *min = NULL;
 474
 475         base += 6; /* skip first id */
 476
 477         for(i = 0; i < max; i++) {
 478                 if (!min || (*base < *min))
 479                         min = base;
 480                 base += 7; /* find next priority */
 481         }
 482
 483         if (!min)
 484                 return NULL;
 485
 486         return (*min < priority) ? (min - 6) : NULL;
 487 }
 488
 489 struct elist_cb_state {
 490         struct net_device *dev;
 491         unsigned char *ptr;
 492         unsigned char *rs;
 493         int t, n;
 494 };
 495
 496 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 497 {
 498         struct elist_cb_state *s = _info;
 499         struct dn_neigh *dn;
 500
 501         if (neigh->dev != s->dev)
 502                 return;
 503
 504         dn = (struct dn_neigh *) neigh;
 505         if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 506                 return;
 507
 508         if (s->t == s->n)
 509                 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 510         else
 511                 s->t++;
 512         if (s->rs == NULL)
 513                 return;
 514
 515         dn_dn2eth(s->rs, dn->addr);
 516         s->rs += 6;
 517         *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 518         *(s->rs) |= dn->priority;
 519         s->rs++;
 520 }
 521
 522 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 523 {
 524         struct elist_cb_state state;
 525
 526         state.dev = dev;
 527         state.t = 0;
 528         state.n = n;
 529         state.ptr = ptr;
 530         state.rs = ptr;
 531
 532         neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 533
 534         return state.t;
 535 }
 536
 537
 538 #ifdef CONFIG_PROC_FS
 539
 540 static inline void dn_neigh_format_entry(struct seq_file *seq,
 541                                          struct neighbour *n)
 542 {
 543         struct dn_neigh *dn = (struct dn_neigh *) n;
 544         char buf[DN_ASCBUF_LEN];
 545
 546         read_lock(&n->lock);
 547         seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 548                    dn_addr2asc(le16_to_cpu(dn->addr), buf),
 549                    (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 550                    (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 551                    (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 552                    dn->n.nud_state,
 553                    atomic_read(&dn->n.refcnt),
 554                    dn->blksize,
 555                    (dn->n.dev) ? dn->n.dev->name : "?");
 556         read_unlock(&n->lock);
 557 }
 558
 559 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 560 {
 561         if (v == SEQ_START_TOKEN) {
 562                 seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 563         } else {
 564                 dn_neigh_format_entry(seq, v);
 565         }
 566
 567         return 0;
 568 }
 569
 570 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 571 {
 572         return neigh_seq_start(seq, pos, &dn_neigh_table,
 573                                NEIGH_SEQ_NEIGH_ONLY);
 574 }
 575
 576 static const struct seq_operations dn_neigh_seq_ops = {
 577         .start = dn_neigh_seq_start,
 578         .next  = neigh_seq_next,
 579         .stop  = neigh_seq_stop,
 580         .show  = dn_neigh_seq_show,
 581 };
 582
 583 static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 584 {
 585         return seq_open_net(inode, file, &dn_neigh_seq_ops,
 586                             sizeof(struct neigh_seq_state));
 587 }
 588
 589 static const struct file_operations dn_neigh_seq_fops = {
 590         .owner          = THIS_MODULE,
 591         .open           = dn_neigh_seq_open,
 592         .read           = seq_read,
 593         .llseek         = seq_lseek,
 594         .release        = seq_release_net,
 595 };
 596
 597 #endif
 598
 599 void __init dn_neigh_init(void)
 600 {
 601         neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
 602         proc_create("decnet_neigh", S_IRUGO, init_net.proc_net,
 603                     &dn_neigh_seq_fops);
 604 }
 605
 606 void __exit dn_neigh_cleanup(void)
 607 {
 608         remove_proc_entry("decnet_neigh", init_net.proc_net);
 609         neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
 610 }