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 <asm/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 u32 dn_neigh_hash(const void *pkey, const struct net_device *dev);
  52 static int dn_neigh_construct(struct neighbour *);
  53 static void dn_long_error_report(struct neighbour *, struct sk_buff *);
  54 static void dn_short_error_report(struct neighbour *, struct sk_buff *);
  55 static int dn_long_output(struct sk_buff *);
  56 static int dn_short_output(struct sk_buff *);
  57 static int dn_phase3_output(struct sk_buff *);
  58
  59
  60 /*
  61  * For talking to broadcast devices: Ethernet & PPP
  62  */
  63 static const struct neigh_ops dn_long_ops = {
  64         .family =               AF_DECnet,
  65         .error_report =         dn_long_error_report,
  66         .output =               dn_long_output,
  67         .connected_output =     dn_long_output,
  68         .hh_output =            dev_queue_xmit,
  69         .queue_xmit =           dev_queue_xmit,
  70 };
  71
  72 /*
  73  * For talking to pointopoint and multidrop devices: DDCMP and X.25
  74  */
  75 static const struct neigh_ops dn_short_ops = {
  76         .family =               AF_DECnet,
  77         .error_report =         dn_short_error_report,
  78         .output =               dn_short_output,
  79         .connected_output =     dn_short_output,
  80         .hh_output =            dev_queue_xmit,
  81         .queue_xmit =           dev_queue_xmit,
  82 };
  83
  84 /*
  85  * For talking to DECnet phase III nodes
  86  */
  87 static const struct neigh_ops dn_phase3_ops = {
  88         .family =               AF_DECnet,
  89         .error_report =         dn_short_error_report, /* Can use short version here */
  90         .output =               dn_phase3_output,
  91         .connected_output =     dn_phase3_output,
  92         .hh_output =            dev_queue_xmit,
  93         .queue_xmit =           dev_queue_xmit
  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 =            3,
 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 u32 dn_neigh_hash(const void *pkey, const struct net_device *dev)
 126 {
 127         return jhash_2words(*(__u16 *)pkey, 0, dn_neigh_table.hash_rnd);
 128 }
 129
 130 static int dn_neigh_construct(struct neighbour *neigh)
 131 {
 132         struct net_device *dev = neigh->dev;
 133         struct dn_neigh *dn = (struct dn_neigh *)neigh;
 134         struct dn_dev *dn_db;
 135         struct neigh_parms *parms;
 136
 137         rcu_read_lock();
 138         dn_db = rcu_dereference(dev->dn_ptr);
 139         if (dn_db == NULL) {
 140                 rcu_read_unlock();
 141                 return -EINVAL;
 142         }
 143
 144         parms = dn_db->neigh_parms;
 145         if (!parms) {
 146                 rcu_read_unlock();
 147                 return -EINVAL;
 148         }
 149
 150         __neigh_parms_put(neigh->parms);
 151         neigh->parms = neigh_parms_clone(parms);
 152
 153         if (dn_db->use_long)
 154                 neigh->ops = &dn_long_ops;
 155         else
 156                 neigh->ops = &dn_short_ops;
 157         rcu_read_unlock();
 158
 159         if (dn->flags & DN_NDFLAG_P3)
 160                 neigh->ops = &dn_phase3_ops;
 161
 162         neigh->nud_state = NUD_NOARP;
 163         neigh->output = neigh->ops->connected_output;
 164
 165         if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 166                 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 167         else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 168                 dn_dn2eth(neigh->ha, dn->addr);
 169         else {
 170                 if (net_ratelimit())
 171                         printk(KERN_DEBUG "Trying to create neigh for hw %d\n",  dev->type);
 172                 return -EINVAL;
 173         }
 174
 175         /*
 176          * Make an estimate of the remote block size by assuming that its
 177          * two less then the device mtu, which it true for ethernet (and
 178          * other things which support long format headers) since there is
 179          * an extra length field (of 16 bits) which isn't part of the
 180          * ethernet headers and which the DECnet specs won't admit is part
 181          * of the DECnet routing headers either.
 182          *
 183          * If we over estimate here its no big deal, the NSP negotiations
 184          * will prevent us from sending packets which are too large for the
 185          * remote node to handle. In any case this figure is normally updated
 186          * by a hello message in most cases.
 187          */
 188         dn->blksize = dev->mtu - 2;
 189
 190         return 0;
 191 }
 192
 193 static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
 194 {
 195         printk(KERN_DEBUG "dn_long_error_report: called\n");
 196         kfree_skb(skb);
 197 }
 198
 199
 200 static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
 201 {
 202         printk(KERN_DEBUG "dn_short_error_report: called\n");
 203         kfree_skb(skb);
 204 }
 205
 206 static int dn_neigh_output_packet(struct sk_buff *skb)
 207 {
 208         struct dst_entry *dst = skb_dst(skb);
 209         struct dn_route *rt = (struct dn_route *)dst;
 210         struct neighbour *neigh = dst->neighbour;
 211         struct net_device *dev = neigh->dev;
 212         char mac_addr[ETH_ALEN];
 213
 214         dn_dn2eth(mac_addr, rt->rt_local_src);
 215         if (dev_hard_header(skb, dev, ntohs(skb->protocol), neigh->ha,
 216                             mac_addr, skb->len) >= 0)
 217                 return neigh->ops->queue_xmit(skb);
 218
 219         if (net_ratelimit())
 220                 printk(KERN_DEBUG "dn_neigh_output_packet: oops, can't send packet\n");
 221
 222         kfree_skb(skb);
 223         return -EINVAL;
 224 }
 225
 226 static int dn_long_output(struct sk_buff *skb)
 227 {
 228         struct dst_entry *dst = skb_dst(skb);
 229         struct neighbour *neigh = dst->neighbour;
 230         struct net_device *dev = neigh->dev;
 231         int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
 232         unsigned char *data;
 233         struct dn_long_packet *lp;
 234         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 235
 236
 237         if (skb_headroom(skb) < headroom) {
 238                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 239                 if (skb2 == NULL) {
 240                         if (net_ratelimit())
 241                                 printk(KERN_CRIT "dn_long_output: no memory\n");
 242                         kfree_skb(skb);
 243                         return -ENOBUFS;
 244                 }
 245                 kfree_skb(skb);
 246                 skb = skb2;
 247                 if (net_ratelimit())
 248                         printk(KERN_INFO "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(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 270 }
 271
 272 static int dn_short_output(struct sk_buff *skb)
 273 {
 274         struct dst_entry *dst = skb_dst(skb);
 275         struct neighbour *neigh = dst->neighbour;
 276         struct net_device *dev = neigh->dev;
 277         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 278         struct dn_short_packet *sp;
 279         unsigned char *data;
 280         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 281
 282
 283         if (skb_headroom(skb) < headroom) {
 284                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 285                 if (skb2 == NULL) {
 286                         if (net_ratelimit())
 287                                 printk(KERN_CRIT "dn_short_output: no memory\n");
 288                         kfree_skb(skb);
 289                         return -ENOBUFS;
 290                 }
 291                 kfree_skb(skb);
 292                 skb = skb2;
 293                 if (net_ratelimit())
 294                         printk(KERN_INFO "dn_short_output: Increasing headroom\n");
 295         }
 296
 297         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 298         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 299         sp = (struct dn_short_packet *)(data+2);
 300
 301         sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 302         sp->dstnode    = cb->dst;
 303         sp->srcnode    = cb->src;
 304         sp->forward    = cb->hops & 0x3f;
 305
 306         skb_reset_network_header(skb);
 307
 308         return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 309 }
 310
 311 /*
 312  * Phase 3 output is the same is short output, execpt that
 313  * it clears the area bits before transmission.
 314  */
 315 static int dn_phase3_output(struct sk_buff *skb)
 316 {
 317         struct dst_entry *dst = skb_dst(skb);
 318         struct neighbour *neigh = dst->neighbour;
 319         struct net_device *dev = neigh->dev;
 320         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 321         struct dn_short_packet *sp;
 322         unsigned char *data;
 323         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 324
 325         if (skb_headroom(skb) < headroom) {
 326                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 327                 if (skb2 == NULL) {
 328                         if (net_ratelimit())
 329                                 printk(KERN_CRIT "dn_phase3_output: no memory\n");
 330                         kfree_skb(skb);
 331                         return -ENOBUFS;
 332                 }
 333                 kfree_skb(skb);
 334                 skb = skb2;
 335                 if (net_ratelimit())
 336                         printk(KERN_INFO "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(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 351 }
 352
 353 /*
 354  * Unfortunately, the neighbour code uses the device in its hash
 355  * function, so we don't get any advantage from it. This function
 356  * basically does a neigh_lookup(), but without comparing the device
 357  * field. This is required for the On-Ethernet cache
 358  */
 359
 360 /*
 361  * Pointopoint link receives a hello message
 362  */
 363 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 364 {
 365         kfree_skb(skb);
 366 }
 367
 368 /*
 369  * Ethernet router hello message received
 370  */
 371 int dn_neigh_router_hello(struct sk_buff *skb)
 372 {
 373         struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 374
 375         struct neighbour *neigh;
 376         struct dn_neigh *dn;
 377         struct dn_dev *dn_db;
 378         __le16 src;
 379
 380         src = dn_eth2dn(msg->id);
 381
 382         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 383
 384         dn = (struct dn_neigh *)neigh;
 385
 386         if (neigh) {
 387                 write_lock(&neigh->lock);
 388
 389                 neigh->used = jiffies;
 390                 dn_db = (struct dn_dev *)neigh->dev->dn_ptr;
 391
 392                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 393                         neigh->updated = jiffies;
 394
 395                         if (neigh->dev->type == ARPHRD_ETHER)
 396                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 397
 398                         dn->blksize  = le16_to_cpu(msg->blksize);
 399                         dn->priority = msg->priority;
 400
 401                         dn->flags &= ~DN_NDFLAG_P3;
 402
 403                         switch(msg->iinfo & DN_RT_INFO_TYPE) {
 404                                 case DN_RT_INFO_L1RT:
 405                                         dn->flags &=~DN_NDFLAG_R2;
 406                                         dn->flags |= DN_NDFLAG_R1;
 407                                         break;
 408                                 case DN_RT_INFO_L2RT:
 409                                         dn->flags |= DN_NDFLAG_R2;
 410                         }
 411                 }
 412
 413                 /* Only use routers in our area */
 414                 if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
 415                         if (!dn_db->router) {
 416                                 dn_db->router = neigh_clone(neigh);
 417                         } else {
 418                                 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 419                                         neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 420                         }
 421                 }
 422                 write_unlock(&neigh->lock);
 423                 neigh_release(neigh);
 424         }
 425
 426         kfree_skb(skb);
 427         return 0;
 428 }
 429
 430 /*
 431  * Endnode hello message received
 432  */
 433 int dn_neigh_endnode_hello(struct sk_buff *skb)
 434 {
 435         struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 436         struct neighbour *neigh;
 437         struct dn_neigh *dn;
 438         __le16 src;
 439
 440         src = dn_eth2dn(msg->id);
 441
 442         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 443
 444         dn = (struct dn_neigh *)neigh;
 445
 446         if (neigh) {
 447                 write_lock(&neigh->lock);
 448
 449                 neigh->used = jiffies;
 450
 451                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 452                         neigh->updated = jiffies;
 453
 454                         if (neigh->dev->type == ARPHRD_ETHER)
 455                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 456                         dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 457                         dn->blksize  = le16_to_cpu(msg->blksize);
 458                         dn->priority = 0;
 459                 }
 460
 461                 write_unlock(&neigh->lock);
 462                 neigh_release(neigh);
 463         }
 464
 465         kfree_skb(skb);
 466         return 0;
 467 }
 468
 469 static char *dn_find_slot(char *base, int max, int priority)
 470 {
 471         int i;
 472         unsigned char *min = NULL;
 473
 474         base += 6; /* skip first id */
 475
 476         for(i = 0; i < max; i++) {
 477                 if (!min || (*base < *min))
 478                         min = base;
 479                 base += 7; /* find next priority */
 480         }
 481
 482         if (!min)
 483                 return NULL;
 484
 485         return (*min < priority) ? (min - 6) : NULL;
 486 }
 487
 488 struct elist_cb_state {
 489         struct net_device *dev;
 490         unsigned char *ptr;
 491         unsigned char *rs;
 492         int t, n;
 493 };
 494
 495 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 496 {
 497         struct elist_cb_state *s = _info;
 498         struct dn_neigh *dn;
 499
 500         if (neigh->dev != s->dev)
 501                 return;
 502
 503         dn = (struct dn_neigh *) neigh;
 504         if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 505                 return;
 506
 507         if (s->t == s->n)
 508                 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 509         else
 510                 s->t++;
 511         if (s->rs == NULL)
 512                 return;
 513
 514         dn_dn2eth(s->rs, dn->addr);
 515         s->rs += 6;
 516         *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 517         *(s->rs) |= dn->priority;
 518         s->rs++;
 519 }
 520
 521 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 522 {
 523         struct elist_cb_state state;
 524
 525         state.dev = dev;
 526         state.t = 0;
 527         state.n = n;
 528         state.ptr = ptr;
 529         state.rs = ptr;
 530
 531         neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 532
 533         return state.t;
 534 }
 535
 536
 537 #ifdef CONFIG_PROC_FS
 538
 539 static inline void dn_neigh_format_entry(struct seq_file *seq,
 540                                          struct neighbour *n)
 541 {
 542         struct dn_neigh *dn = (struct dn_neigh *) n;
 543         char buf[DN_ASCBUF_LEN];
 544
 545         read_lock(&n->lock);
 546         seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 547                    dn_addr2asc(le16_to_cpu(dn->addr), buf),
 548                    (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 549                    (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 550                    (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 551                    dn->n.nud_state,
 552                    atomic_read(&dn->n.refcnt),
 553                    dn->blksize,
 554                    (dn->n.dev) ? dn->n.dev->name : "?");
 555         read_unlock(&n->lock);
 556 }
 557
 558 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 559 {
 560         if (v == SEQ_START_TOKEN) {
 561                 seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 562         } else {
 563                 dn_neigh_format_entry(seq, v);
 564         }
 565
 566         return 0;
 567 }
 568
 569 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 570 {
 571         return neigh_seq_start(seq, pos, &dn_neigh_table,
 572                                NEIGH_SEQ_NEIGH_ONLY);
 573 }
 574
 575 static const struct seq_operations dn_neigh_seq_ops = {
 576         .start = dn_neigh_seq_start,
 577         .next  = neigh_seq_next,
 578         .stop  = neigh_seq_stop,
 579         .show  = dn_neigh_seq_show,
 580 };
 581
 582 static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 583 {
 584         return seq_open_net(inode, file, &dn_neigh_seq_ops,
 585                             sizeof(struct neigh_seq_state));
 586 }
 587
 588 static const struct file_operations dn_neigh_seq_fops = {
 589         .owner          = THIS_MODULE,
 590         .open           = dn_neigh_seq_open,
 591         .read           = seq_read,
 592         .llseek         = seq_lseek,
 593         .release        = seq_release_net,
 594 };
 595
 596 #endif
 597
 598 void __init dn_neigh_init(void)
 599 {
 600         neigh_table_init(&dn_neigh_table);
 601         proc_net_fops_create(&init_net, "decnet_neigh", S_IRUGO, &dn_neigh_seq_fops);
 602 }
 603
 604 void __exit dn_neigh_cleanup(void)
 605 {
 606         proc_net_remove(&init_net, "decnet_neigh");
 607         neigh_table_clear(&dn_neigh_table);
 608 }