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/if_ether.h>
  32 #include <linux/init.h>
  33 #include <linux/proc_fs.h>
  34 #include <linux/string.h>
  35 #include <linux/netfilter_decnet.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/seq_file.h>
  38 #include <linux/rcupdate.h>
  39 #include <linux/jhash.h>
  40 #include <asm/atomic.h>
  41 #include <net/net_namespace.h>
  42 #include <net/neighbour.h>
  43 #include <net/dst.h>
  44 #include <net/flow.h>
  45 #include <net/dn.h>
  46 #include <net/dn_dev.h>
  47 #include <net/dn_neigh.h>
  48 #include <net/dn_route.h>
  49
  50 static u32 dn_neigh_hash(const void *pkey, const struct net_device *dev);
  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 sk_buff *);
  55 static int dn_short_output(struct sk_buff *);
  56 static int dn_phase3_output(struct sk_buff *);
  57
  58
  59 /*
  60  * For talking to broadcast devices: Ethernet & PPP
  61  */
  62 static 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         .hh_output =            dev_queue_xmit,
  68         .queue_xmit =           dev_queue_xmit,
  69 };
  70
  71 /*
  72  * For talking to pointopoint and multidrop devices: DDCMP and X.25
  73  */
  74 static struct neigh_ops dn_short_ops = {
  75         .family =               AF_DECnet,
  76         .error_report =         dn_short_error_report,
  77         .output =               dn_short_output,
  78         .connected_output =     dn_short_output,
  79         .hh_output =            dev_queue_xmit,
  80         .queue_xmit =           dev_queue_xmit,
  81 };
  82
  83 /*
  84  * For talking to DECnet phase III nodes
  85  */
  86 static struct neigh_ops dn_phase3_ops = {
  87         .family =               AF_DECnet,
  88         .error_report =         dn_short_error_report, /* Can use short version here */
  89         .output =               dn_phase3_output,
  90         .connected_output =     dn_phase3_output,
  91         .hh_output =            dev_queue_xmit,
  92         .queue_xmit =           dev_queue_xmit
  93 };
  94
  95 struct neigh_table dn_neigh_table = {
  96         .family =                       PF_DECnet,
  97         .entry_size =                   sizeof(struct dn_neigh),
  98         .key_len =                      sizeof(__le16),
  99         .hash =                         dn_neigh_hash,
 100         .constructor =                  dn_neigh_construct,
 101         .id =                           "dn_neigh_cache",
 102         .parms ={
 103                 .tbl =                  &dn_neigh_table,
 104                 .base_reachable_time =  30 * HZ,
 105                 .retrans_time = 1 * HZ,
 106                 .gc_staletime = 60 * HZ,
 107                 .reachable_time =               30 * HZ,
 108                 .delay_probe_time =     5 * HZ,
 109                 .queue_len =            3,
 110                 .ucast_probes = 0,
 111                 .app_probes =           0,
 112                 .mcast_probes = 0,
 113                 .anycast_delay =        0,
 114                 .proxy_delay =          0,
 115                 .proxy_qlen =           0,
 116                 .locktime =             1 * HZ,
 117         },
 118         .gc_interval =                  30 * HZ,
 119         .gc_thresh1 =                   128,
 120         .gc_thresh2 =                   512,
 121         .gc_thresh3 =                   1024,
 122 };
 123
 124 static u32 dn_neigh_hash(const void *pkey, const struct net_device *dev)
 125 {
 126         return jhash_2words(*(__u16 *)pkey, 0, dn_neigh_table.hash_rnd);
 127 }
 128
 129 static int dn_neigh_construct(struct neighbour *neigh)
 130 {
 131         struct net_device *dev = neigh->dev;
 132         struct dn_neigh *dn = (struct dn_neigh *)neigh;
 133         struct dn_dev *dn_db;
 134         struct neigh_parms *parms;
 135
 136         rcu_read_lock();
 137         dn_db = rcu_dereference(dev->dn_ptr);
 138         if (dn_db == NULL) {
 139                 rcu_read_unlock();
 140                 return -EINVAL;
 141         }
 142
 143         parms = dn_db->neigh_parms;
 144         if (!parms) {
 145                 rcu_read_unlock();
 146                 return -EINVAL;
 147         }
 148
 149         __neigh_parms_put(neigh->parms);
 150         neigh->parms = neigh_parms_clone(parms);
 151
 152         if (dn_db->use_long)
 153                 neigh->ops = &dn_long_ops;
 154         else
 155                 neigh->ops = &dn_short_ops;
 156         rcu_read_unlock();
 157
 158         if (dn->flags & DN_NDFLAG_P3)
 159                 neigh->ops = &dn_phase3_ops;
 160
 161         neigh->nud_state = NUD_NOARP;
 162         neigh->output = neigh->ops->connected_output;
 163
 164         if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 165                 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 166         else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 167                 dn_dn2eth(neigh->ha, dn->addr);
 168         else {
 169                 if (net_ratelimit())
 170                         printk(KERN_DEBUG "Trying to create neigh for hw %d\n",  dev->type);
 171                 return -EINVAL;
 172         }
 173
 174         /*
 175          * Make an estimate of the remote block size by assuming that its
 176          * two less then the device mtu, which it true for ethernet (and
 177          * other things which support long format headers) since there is
 178          * an extra length field (of 16 bits) which isn't part of the
 179          * ethernet headers and which the DECnet specs won't admit is part
 180          * of the DECnet routing headers either.
 181          *
 182          * If we over estimate here its no big deal, the NSP negotiations
 183          * will prevent us from sending packets which are too large for the
 184          * remote node to handle. In any case this figure is normally updated
 185          * by a hello message in most cases.
 186          */
 187         dn->blksize = dev->mtu - 2;
 188
 189         return 0;
 190 }
 191
 192 static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
 193 {
 194         printk(KERN_DEBUG "dn_long_error_report: called\n");
 195         kfree_skb(skb);
 196 }
 197
 198
 199 static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
 200 {
 201         printk(KERN_DEBUG "dn_short_error_report: called\n");
 202         kfree_skb(skb);
 203 }
 204
 205 static int dn_neigh_output_packet(struct sk_buff *skb)
 206 {
 207         struct dst_entry *dst = skb->dst;
 208         struct dn_route *rt = (struct dn_route *)dst;
 209         struct neighbour *neigh = dst->neighbour;
 210         struct net_device *dev = neigh->dev;
 211         char mac_addr[ETH_ALEN];
 212
 213         dn_dn2eth(mac_addr, rt->rt_local_src);
 214         if (dev_hard_header(skb, dev, ntohs(skb->protocol), neigh->ha,
 215                             mac_addr, skb->len) >= 0)
 216                 return neigh->ops->queue_xmit(skb);
 217
 218         if (net_ratelimit())
 219                 printk(KERN_DEBUG "dn_neigh_output_packet: oops, can't send packet\n");
 220
 221         kfree_skb(skb);
 222         return -EINVAL;
 223 }
 224
 225 static int dn_long_output(struct sk_buff *skb)
 226 {
 227         struct dst_entry *dst = skb->dst;
 228         struct neighbour *neigh = dst->neighbour;
 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) = dn_htons(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(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 269 }
 270
 271 static int dn_short_output(struct sk_buff *skb)
 272 {
 273         struct dst_entry *dst = skb->dst;
 274         struct neighbour *neigh = dst->neighbour;
 275         struct net_device *dev = neigh->dev;
 276         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 277         struct dn_short_packet *sp;
 278         unsigned char *data;
 279         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 280
 281
 282         if (skb_headroom(skb) < headroom) {
 283                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 284                 if (skb2 == NULL) {
 285                         if (net_ratelimit())
 286                                 printk(KERN_CRIT "dn_short_output: no memory\n");
 287                         kfree_skb(skb);
 288                         return -ENOBUFS;
 289                 }
 290                 kfree_skb(skb);
 291                 skb = skb2;
 292                 if (net_ratelimit())
 293                         printk(KERN_INFO "dn_short_output: Increasing headroom\n");
 294         }
 295
 296         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 297         *((__le16 *)data) = dn_htons(skb->len - 2);
 298         sp = (struct dn_short_packet *)(data+2);
 299
 300         sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 301         sp->dstnode    = cb->dst;
 302         sp->srcnode    = cb->src;
 303         sp->forward    = cb->hops & 0x3f;
 304
 305         skb_reset_network_header(skb);
 306
 307         return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, 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 sk_buff *skb)
 315 {
 316         struct dst_entry *dst = skb->dst;
 317         struct neighbour *neigh = dst->neighbour;
 318         struct net_device *dev = neigh->dev;
 319         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 320         struct dn_short_packet *sp;
 321         unsigned char *data;
 322         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 323
 324         if (skb_headroom(skb) < headroom) {
 325                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 326                 if (skb2 == NULL) {
 327                         if (net_ratelimit())
 328                                 printk(KERN_CRIT "dn_phase3_output: no memory\n");
 329                         kfree_skb(skb);
 330                         return -ENOBUFS;
 331                 }
 332                 kfree_skb(skb);
 333                 skb = skb2;
 334                 if (net_ratelimit())
 335                         printk(KERN_INFO "dn_phase3_output: Increasing headroom\n");
 336         }
 337
 338         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 339         *((__le16 *)data) = dn_htons(skb->len - 2);
 340         sp = (struct dn_short_packet *)(data + 2);
 341
 342         sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 343         sp->dstnode  = cb->dst & dn_htons(0x03ff);
 344         sp->srcnode  = cb->src & dn_htons(0x03ff);
 345         sp->forward  = cb->hops & 0x3f;
 346
 347         skb_reset_network_header(skb);
 348
 349         return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 350 }
 351
 352 /*
 353  * Unfortunately, the neighbour code uses the device in its hash
 354  * function, so we don't get any advantage from it. This function
 355  * basically does a neigh_lookup(), but without comparing the device
 356  * field. This is required for the On-Ethernet cache
 357  */
 358
 359 /*
 360  * Pointopoint link receives a hello message
 361  */
 362 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 363 {
 364         kfree_skb(skb);
 365 }
 366
 367 /*
 368  * Ethernet router hello message received
 369  */
 370 int dn_neigh_router_hello(struct sk_buff *skb)
 371 {
 372         struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 373
 374         struct neighbour *neigh;
 375         struct dn_neigh *dn;
 376         struct dn_dev *dn_db;
 377         __le16 src;
 378
 379         src = dn_eth2dn(msg->id);
 380
 381         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 382
 383         dn = (struct dn_neigh *)neigh;
 384
 385         if (neigh) {
 386                 write_lock(&neigh->lock);
 387
 388                 neigh->used = jiffies;
 389                 dn_db = (struct dn_dev *)neigh->dev->dn_ptr;
 390
 391                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 392                         neigh->updated = jiffies;
 393
 394                         if (neigh->dev->type == ARPHRD_ETHER)
 395                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 396
 397                         dn->blksize  = dn_ntohs(msg->blksize);
 398                         dn->priority = msg->priority;
 399
 400                         dn->flags &= ~DN_NDFLAG_P3;
 401
 402                         switch(msg->iinfo & DN_RT_INFO_TYPE) {
 403                                 case DN_RT_INFO_L1RT:
 404                                         dn->flags &=~DN_NDFLAG_R2;
 405                                         dn->flags |= DN_NDFLAG_R1;
 406                                         break;
 407                                 case DN_RT_INFO_L2RT:
 408                                         dn->flags |= DN_NDFLAG_R2;
 409                         }
 410                 }
 411
 412                 /* Only use routers in our area */
 413                 if ((dn_ntohs(src)>>10) == (dn_ntohs((decnet_address))>>10)) {
 414                         if (!dn_db->router) {
 415                                 dn_db->router = neigh_clone(neigh);
 416                         } else {
 417                                 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 418                                         neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 419                         }
 420                 }
 421                 write_unlock(&neigh->lock);
 422                 neigh_release(neigh);
 423         }
 424
 425         kfree_skb(skb);
 426         return 0;
 427 }
 428
 429 /*
 430  * Endnode hello message received
 431  */
 432 int dn_neigh_endnode_hello(struct sk_buff *skb)
 433 {
 434         struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 435         struct neighbour *neigh;
 436         struct dn_neigh *dn;
 437         __le16 src;
 438
 439         src = dn_eth2dn(msg->id);
 440
 441         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 442
 443         dn = (struct dn_neigh *)neigh;
 444
 445         if (neigh) {
 446                 write_lock(&neigh->lock);
 447
 448                 neigh->used = jiffies;
 449
 450                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 451                         neigh->updated = jiffies;
 452
 453                         if (neigh->dev->type == ARPHRD_ETHER)
 454                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 455                         dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 456                         dn->blksize  = dn_ntohs(msg->blksize);
 457                         dn->priority = 0;
 458                 }
 459
 460                 write_unlock(&neigh->lock);
 461                 neigh_release(neigh);
 462         }
 463
 464         kfree_skb(skb);
 465         return 0;
 466 }
 467
 468 static char *dn_find_slot(char *base, int max, int priority)
 469 {
 470         int i;
 471         unsigned char *min = NULL;
 472
 473         base += 6; /* skip first id */
 474
 475         for(i = 0; i < max; i++) {
 476                 if (!min || (*base < *min))
 477                         min = base;
 478                 base += 7; /* find next priority */
 479         }
 480
 481         if (!min)
 482                 return NULL;
 483
 484         return (*min < priority) ? (min - 6) : NULL;
 485 }
 486
 487 struct elist_cb_state {
 488         struct net_device *dev;
 489         unsigned char *ptr;
 490         unsigned char *rs;
 491         int t, n;
 492 };
 493
 494 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 495 {
 496         struct elist_cb_state *s = _info;
 497         struct dn_neigh *dn;
 498
 499         if (neigh->dev != s->dev)
 500                 return;
 501
 502         dn = (struct dn_neigh *) neigh;
 503         if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 504                 return;
 505
 506         if (s->t == s->n)
 507                 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 508         else
 509                 s->t++;
 510         if (s->rs == NULL)
 511                 return;
 512
 513         dn_dn2eth(s->rs, dn->addr);
 514         s->rs += 6;
 515         *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 516         *(s->rs) |= dn->priority;
 517         s->rs++;
 518 }
 519
 520 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 521 {
 522         struct elist_cb_state state;
 523
 524         state.dev = dev;
 525         state.t = 0;
 526         state.n = n;
 527         state.ptr = ptr;
 528         state.rs = ptr;
 529
 530         neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 531
 532         return state.t;
 533 }
 534
 535
 536 #ifdef CONFIG_PROC_FS
 537
 538 static inline void dn_neigh_format_entry(struct seq_file *seq,
 539                                          struct neighbour *n)
 540 {
 541         struct dn_neigh *dn = (struct dn_neigh *) n;
 542         char buf[DN_ASCBUF_LEN];
 543
 544         read_lock(&n->lock);
 545         seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 546                    dn_addr2asc(dn_ntohs(dn->addr), buf),
 547                    (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 548                    (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 549                    (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 550                    dn->n.nud_state,
 551                    atomic_read(&dn->n.refcnt),
 552                    dn->blksize,
 553                    (dn->n.dev) ? dn->n.dev->name : "?");
 554         read_unlock(&n->lock);
 555 }
 556
 557 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 558 {
 559         if (v == SEQ_START_TOKEN) {
 560                 seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 561         } else {
 562                 dn_neigh_format_entry(seq, v);
 563         }
 564
 565         return 0;
 566 }
 567
 568 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 569 {
 570         return neigh_seq_start(seq, pos, &dn_neigh_table,
 571                                NEIGH_SEQ_NEIGH_ONLY);
 572 }
 573
 574 static const struct seq_operations dn_neigh_seq_ops = {
 575         .start = dn_neigh_seq_start,
 576         .next  = neigh_seq_next,
 577         .stop  = neigh_seq_stop,
 578         .show  = dn_neigh_seq_show,
 579 };
 580
 581 static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 582 {
 583         return seq_open_private(file, &dn_neigh_seq_ops,
 584                         sizeof(struct neigh_seq_state));
 585 }
 586
 587 static const struct file_operations dn_neigh_seq_fops = {
 588         .owner          = THIS_MODULE,
 589         .open           = dn_neigh_seq_open,
 590         .read           = seq_read,
 591         .llseek         = seq_lseek,
 592         .release        = seq_release_private,
 593 };
 594
 595 #endif
 596
 597 void __init dn_neigh_init(void)
 598 {
 599         neigh_table_init(&dn_neigh_table);
 600         proc_net_fops_create(&init_net, "decnet_neigh", S_IRUGO, &dn_neigh_seq_fops);
 601 }
 602
 603 void __exit dn_neigh_cleanup(void)
 604 {
 605         proc_net_remove(&init_net, "decnet_neigh");
 606         neigh_table_clear(&dn_neigh_table);
 607 }