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