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