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                 if (net_ratelimit())
 166                         printk(KERN_DEBUG "Trying to create neigh for hw %d\n",  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 = dst_get_neighbour_noref(dst);
 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                         if (net_ratelimit())
 240                                 printk(KERN_CRIT "dn_long_output: no memory\n");
 241                         kfree_skb(skb);
 242                         return -ENOBUFS;
 243                 }
 244                 kfree_skb(skb);
 245                 skb = skb2;
 246                 if (net_ratelimit())
 247                         printk(KERN_INFO "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                         if (net_ratelimit())
 285                                 printk(KERN_CRIT "dn_short_output: no memory\n");
 286                         kfree_skb(skb);
 287                         return -ENOBUFS;
 288                 }
 289                 kfree_skb(skb);
 290                 skb = skb2;
 291                 if (net_ratelimit())
 292                         printk(KERN_INFO "dn_short_output: Increasing headroom\n");
 293         }
 294
 295         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 296         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 297         sp = (struct dn_short_packet *)(data+2);
 298
 299         sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 300         sp->dstnode    = cb->dst;
 301         sp->srcnode    = cb->src;
 302         sp->forward    = cb->hops & 0x3f;
 303
 304         skb_reset_network_header(skb);
 305
 306         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 307                        neigh->dev, dn_neigh_output_packet);
 308 }
 309
 310 /*
 311  * Phase 3 output is the same is short output, execpt that
 312  * it clears the area bits before transmission.
 313  */
 314 static int dn_phase3_output(struct neighbour *neigh, struct sk_buff *skb)
 315 {
 316         struct net_device *dev = neigh->dev;
 317         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 318         struct dn_short_packet *sp;
 319         unsigned char *data;
 320         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 321
 322         if (skb_headroom(skb) < headroom) {
 323                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 324                 if (skb2 == NULL) {
 325                         if (net_ratelimit())
 326                                 printk(KERN_CRIT "dn_phase3_output: no memory\n");
 327                         kfree_skb(skb);
 328                         return -ENOBUFS;
 329                 }
 330                 kfree_skb(skb);
 331                 skb = skb2;
 332                 if (net_ratelimit())
 333                         printk(KERN_INFO "dn_phase3_output: Increasing headroom\n");
 334         }
 335
 336         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 337         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 338         sp = (struct dn_short_packet *)(data + 2);
 339
 340         sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 341         sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
 342         sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
 343         sp->forward  = cb->hops & 0x3f;
 344
 345         skb_reset_network_header(skb);
 346
 347         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 348                        neigh->dev, dn_neigh_output_packet);
 349 }
 350
 351 /*
 352  * Unfortunately, the neighbour code uses the device in its hash
 353  * function, so we don't get any advantage from it. This function
 354  * basically does a neigh_lookup(), but without comparing the device
 355  * field. This is required for the On-Ethernet cache
 356  */
 357
 358 /*
 359  * Pointopoint link receives a hello message
 360  */
 361 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 362 {
 363         kfree_skb(skb);
 364 }
 365
 366 /*
 367  * Ethernet router hello message received
 368  */
 369 int dn_neigh_router_hello(struct sk_buff *skb)
 370 {
 371         struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 372
 373         struct neighbour *neigh;
 374         struct dn_neigh *dn;
 375         struct dn_dev *dn_db;
 376         __le16 src;
 377
 378         src = dn_eth2dn(msg->id);
 379
 380         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 381
 382         dn = (struct dn_neigh *)neigh;
 383
 384         if (neigh) {
 385                 write_lock(&neigh->lock);
 386
 387                 neigh->used = jiffies;
 388                 dn_db = rcu_dereference(neigh->dev->dn_ptr);
 389
 390                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 391                         neigh->updated = jiffies;
 392
 393                         if (neigh->dev->type == ARPHRD_ETHER)
 394                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 395
 396                         dn->blksize  = le16_to_cpu(msg->blksize);
 397                         dn->priority = msg->priority;
 398
 399                         dn->flags &= ~DN_NDFLAG_P3;
 400
 401                         switch (msg->iinfo & DN_RT_INFO_TYPE) {
 402                         case DN_RT_INFO_L1RT:
 403                                 dn->flags &=~DN_NDFLAG_R2;
 404                                 dn->flags |= DN_NDFLAG_R1;
 405                                 break;
 406                         case DN_RT_INFO_L2RT:
 407                                 dn->flags |= DN_NDFLAG_R2;
 408                         }
 409                 }
 410
 411                 /* Only use routers in our area */
 412                 if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
 413                         if (!dn_db->router) {
 414                                 dn_db->router = neigh_clone(neigh);
 415                         } else {
 416                                 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 417                                         neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 418                         }
 419                 }
 420                 write_unlock(&neigh->lock);
 421                 neigh_release(neigh);
 422         }
 423
 424         kfree_skb(skb);
 425         return 0;
 426 }
 427
 428 /*
 429  * Endnode hello message received
 430  */
 431 int dn_neigh_endnode_hello(struct sk_buff *skb)
 432 {
 433         struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 434         struct neighbour *neigh;
 435         struct dn_neigh *dn;
 436         __le16 src;
 437
 438         src = dn_eth2dn(msg->id);
 439
 440         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 441
 442         dn = (struct dn_neigh *)neigh;
 443
 444         if (neigh) {
 445                 write_lock(&neigh->lock);
 446
 447                 neigh->used = jiffies;
 448
 449                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 450                         neigh->updated = jiffies;
 451
 452                         if (neigh->dev->type == ARPHRD_ETHER)
 453                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 454                         dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 455                         dn->blksize  = le16_to_cpu(msg->blksize);
 456                         dn->priority = 0;
 457                 }
 458
 459                 write_unlock(&neigh->lock);
 460                 neigh_release(neigh);
 461         }
 462
 463         kfree_skb(skb);
 464         return 0;
 465 }
 466
 467 static char *dn_find_slot(char *base, int max, int priority)
 468 {
 469         int i;
 470         unsigned char *min = NULL;
 471
 472         base += 6; /* skip first id */
 473
 474         for(i = 0; i < max; i++) {
 475                 if (!min || (*base < *min))
 476                         min = base;
 477                 base += 7; /* find next priority */
 478         }
 479
 480         if (!min)
 481                 return NULL;
 482
 483         return (*min < priority) ? (min - 6) : NULL;
 484 }
 485
 486 struct elist_cb_state {
 487         struct net_device *dev;
 488         unsigned char *ptr;
 489         unsigned char *rs;
 490         int t, n;
 491 };
 492
 493 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 494 {
 495         struct elist_cb_state *s = _info;
 496         struct dn_neigh *dn;
 497
 498         if (neigh->dev != s->dev)
 499                 return;
 500
 501         dn = (struct dn_neigh *) neigh;
 502         if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 503                 return;
 504
 505         if (s->t == s->n)
 506                 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 507         else
 508                 s->t++;
 509         if (s->rs == NULL)
 510                 return;
 511
 512         dn_dn2eth(s->rs, dn->addr);
 513         s->rs += 6;
 514         *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 515         *(s->rs) |= dn->priority;
 516         s->rs++;
 517 }
 518
 519 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 520 {
 521         struct elist_cb_state state;
 522
 523         state.dev = dev;
 524         state.t = 0;
 525         state.n = n;
 526         state.ptr = ptr;
 527         state.rs = ptr;
 528
 529         neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 530
 531         return state.t;
 532 }
 533
 534
 535 #ifdef CONFIG_PROC_FS
 536
 537 static inline void dn_neigh_format_entry(struct seq_file *seq,
 538                                          struct neighbour *n)
 539 {
 540         struct dn_neigh *dn = (struct dn_neigh *) n;
 541         char buf[DN_ASCBUF_LEN];
 542
 543         read_lock(&n->lock);
 544         seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 545                    dn_addr2asc(le16_to_cpu(dn->addr), buf),
 546                    (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 547                    (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 548                    (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 549                    dn->n.nud_state,
 550                    atomic_read(&dn->n.refcnt),
 551                    dn->blksize,
 552                    (dn->n.dev) ? dn->n.dev->name : "?");
 553         read_unlock(&n->lock);
 554 }
 555
 556 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 557 {
 558         if (v == SEQ_START_TOKEN) {
 559                 seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 560         } else {
 561                 dn_neigh_format_entry(seq, v);
 562         }
 563
 564         return 0;
 565 }
 566
 567 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 568 {
 569         return neigh_seq_start(seq, pos, &dn_neigh_table,
 570                                NEIGH_SEQ_NEIGH_ONLY);
 571 }
 572
 573 static const struct seq_operations dn_neigh_seq_ops = {
 574         .start = dn_neigh_seq_start,
 575         .next  = neigh_seq_next,
 576         .stop  = neigh_seq_stop,
 577         .show  = dn_neigh_seq_show,
 578 };
 579
 580 static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 581 {
 582         return seq_open_net(inode, file, &dn_neigh_seq_ops,
 583                             sizeof(struct neigh_seq_state));
 584 }
 585
 586 static const struct file_operations dn_neigh_seq_fops = {
 587         .owner          = THIS_MODULE,
 588         .open           = dn_neigh_seq_open,
 589         .read           = seq_read,
 590         .llseek         = seq_lseek,
 591         .release        = seq_release_net,
 592 };
 593
 594 #endif
 595
 596 void __init dn_neigh_init(void)
 597 {
 598         neigh_table_init(&dn_neigh_table);
 599         proc_net_fops_create(&init_net, "decnet_neigh", S_IRUGO, &dn_neigh_seq_fops);
 600 }
 601
 602 void __exit dn_neigh_cleanup(void)
 603 {
 604         proc_net_remove(&init_net, "decnet_neigh");
 605         neigh_table_clear(&dn_neigh_table);
 606 }