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 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 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         .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 const 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 const 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 static u32 dn_neigh_hash(const void *pkey,
  96                          const struct net_device *dev,
  97                          __u32 hash_rnd)
  98 {
  99         return jhash_2words(*(__u16 *)pkey, 0, hash_rnd);
 100 }
 101
 102 struct neigh_table dn_neigh_table = {
 103         .family =                       PF_DECnet,
 104         .entry_size =                   sizeof(struct dn_neigh),
 105         .key_len =                      sizeof(__le16),
 106         .hash =                         dn_neigh_hash,
 107         .constructor =                  dn_neigh_construct,
 108         .id =                           "dn_neigh_cache",
 109         .parms ={
 110                 .tbl =                  &dn_neigh_table,
 111                 .base_reachable_time =  30 * HZ,
 112                 .retrans_time = 1 * HZ,
 113                 .gc_staletime = 60 * HZ,
 114                 .reachable_time =               30 * HZ,
 115                 .delay_probe_time =     5 * HZ,
 116                 .queue_len =            3,
 117                 .ucast_probes = 0,
 118                 .app_probes =           0,
 119                 .mcast_probes = 0,
 120                 .anycast_delay =        0,
 121                 .proxy_delay =          0,
 122                 .proxy_qlen =           0,
 123                 .locktime =             1 * HZ,
 124         },
 125         .gc_interval =                  30 * HZ,
 126         .gc_thresh1 =                   128,
 127         .gc_thresh2 =                   512,
 128         .gc_thresh3 =                   1024,
 129 };
 130
 131 static int dn_neigh_construct(struct neighbour *neigh)
 132 {
 133         struct net_device *dev = neigh->dev;
 134         struct dn_neigh *dn = (struct dn_neigh *)neigh;
 135         struct dn_dev *dn_db;
 136         struct neigh_parms *parms;
 137
 138         rcu_read_lock();
 139         dn_db = rcu_dereference(dev->dn_ptr);
 140         if (dn_db == NULL) {
 141                 rcu_read_unlock();
 142                 return -EINVAL;
 143         }
 144
 145         parms = dn_db->neigh_parms;
 146         if (!parms) {
 147                 rcu_read_unlock();
 148                 return -EINVAL;
 149         }
 150
 151         __neigh_parms_put(neigh->parms);
 152         neigh->parms = neigh_parms_clone(parms);
 153
 154         if (dn_db->use_long)
 155                 neigh->ops = &dn_long_ops;
 156         else
 157                 neigh->ops = &dn_short_ops;
 158         rcu_read_unlock();
 159
 160         if (dn->flags & DN_NDFLAG_P3)
 161                 neigh->ops = &dn_phase3_ops;
 162
 163         neigh->nud_state = NUD_NOARP;
 164         neigh->output = neigh->ops->connected_output;
 165
 166         if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 167                 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 168         else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 169                 dn_dn2eth(neigh->ha, dn->addr);
 170         else {
 171                 if (net_ratelimit())
 172                         printk(KERN_DEBUG "Trying to create neigh for hw %d\n",  dev->type);
 173                 return -EINVAL;
 174         }
 175
 176         /*
 177          * Make an estimate of the remote block size by assuming that its
 178          * two less then the device mtu, which it true for ethernet (and
 179          * other things which support long format headers) since there is
 180          * an extra length field (of 16 bits) which isn't part of the
 181          * ethernet headers and which the DECnet specs won't admit is part
 182          * of the DECnet routing headers either.
 183          *
 184          * If we over estimate here its no big deal, the NSP negotiations
 185          * will prevent us from sending packets which are too large for the
 186          * remote node to handle. In any case this figure is normally updated
 187          * by a hello message in most cases.
 188          */
 189         dn->blksize = dev->mtu - 2;
 190
 191         return 0;
 192 }
 193
 194 static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
 195 {
 196         printk(KERN_DEBUG "dn_long_error_report: called\n");
 197         kfree_skb(skb);
 198 }
 199
 200
 201 static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
 202 {
 203         printk(KERN_DEBUG "dn_short_error_report: called\n");
 204         kfree_skb(skb);
 205 }
 206
 207 static int dn_neigh_output_packet(struct sk_buff *skb)
 208 {
 209         struct dst_entry *dst = skb_dst(skb);
 210         struct dn_route *rt = (struct dn_route *)dst;
 211         struct neighbour *neigh = dst->neighbour;
 212         struct net_device *dev = neigh->dev;
 213         char mac_addr[ETH_ALEN];
 214
 215         dn_dn2eth(mac_addr, rt->rt_local_src);
 216         if (dev_hard_header(skb, dev, ntohs(skb->protocol), neigh->ha,
 217                             mac_addr, skb->len) >= 0)
 218                 return neigh->ops->queue_xmit(skb);
 219
 220         if (net_ratelimit())
 221                 printk(KERN_DEBUG "dn_neigh_output_packet: oops, can't send packet\n");
 222
 223         kfree_skb(skb);
 224         return -EINVAL;
 225 }
 226
 227 static int dn_long_output(struct sk_buff *skb)
 228 {
 229         struct dst_entry *dst = skb_dst(skb);
 230         struct neighbour *neigh = dst->neighbour;
 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                         if (net_ratelimit())
 242                                 printk(KERN_CRIT "dn_long_output: no memory\n");
 243                         kfree_skb(skb);
 244                         return -ENOBUFS;
 245                 }
 246                 kfree_skb(skb);
 247                 skb = skb2;
 248                 if (net_ratelimit())
 249                         printk(KERN_INFO "dn_long_output: Increasing headroom\n");
 250         }
 251
 252         data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
 253         lp = (struct dn_long_packet *)(data+3);
 254
 255         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 256         *(data + 2) = 1 | DN_RT_F_PF; /* Padding */
 257
 258         lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
 259         lp->d_area   = lp->d_subarea = 0;
 260         dn_dn2eth(lp->d_id, cb->dst);
 261         lp->s_area   = lp->s_subarea = 0;
 262         dn_dn2eth(lp->s_id, cb->src);
 263         lp->nl2      = 0;
 264         lp->visit_ct = cb->hops & 0x3f;
 265         lp->s_class  = 0;
 266         lp->pt       = 0;
 267
 268         skb_reset_network_header(skb);
 269
 270         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 271                        neigh->dev, dn_neigh_output_packet);
 272 }
 273
 274 static int dn_short_output(struct sk_buff *skb)
 275 {
 276         struct dst_entry *dst = skb_dst(skb);
 277         struct neighbour *neigh = dst->neighbour;
 278         struct net_device *dev = neigh->dev;
 279         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 280         struct dn_short_packet *sp;
 281         unsigned char *data;
 282         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 283
 284
 285         if (skb_headroom(skb) < headroom) {
 286                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 287                 if (skb2 == NULL) {
 288                         if (net_ratelimit())
 289                                 printk(KERN_CRIT "dn_short_output: no memory\n");
 290                         kfree_skb(skb);
 291                         return -ENOBUFS;
 292                 }
 293                 kfree_skb(skb);
 294                 skb = skb2;
 295                 if (net_ratelimit())
 296                         printk(KERN_INFO "dn_short_output: Increasing headroom\n");
 297         }
 298
 299         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 300         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 301         sp = (struct dn_short_packet *)(data+2);
 302
 303         sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 304         sp->dstnode    = cb->dst;
 305         sp->srcnode    = cb->src;
 306         sp->forward    = cb->hops & 0x3f;
 307
 308         skb_reset_network_header(skb);
 309
 310         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 311                        neigh->dev, dn_neigh_output_packet);
 312 }
 313
 314 /*
 315  * Phase 3 output is the same is short output, execpt that
 316  * it clears the area bits before transmission.
 317  */
 318 static int dn_phase3_output(struct sk_buff *skb)
 319 {
 320         struct dst_entry *dst = skb_dst(skb);
 321         struct neighbour *neigh = dst->neighbour;
 322         struct net_device *dev = neigh->dev;
 323         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 324         struct dn_short_packet *sp;
 325         unsigned char *data;
 326         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 327
 328         if (skb_headroom(skb) < headroom) {
 329                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 330                 if (skb2 == NULL) {
 331                         if (net_ratelimit())
 332                                 printk(KERN_CRIT "dn_phase3_output: no memory\n");
 333                         kfree_skb(skb);
 334                         return -ENOBUFS;
 335                 }
 336                 kfree_skb(skb);
 337                 skb = skb2;
 338                 if (net_ratelimit())
 339                         printk(KERN_INFO "dn_phase3_output: Increasing headroom\n");
 340         }
 341
 342         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 343         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 344         sp = (struct dn_short_packet *)(data + 2);
 345
 346         sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 347         sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
 348         sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
 349         sp->forward  = cb->hops & 0x3f;
 350
 351         skb_reset_network_header(skb);
 352
 353         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 354                        neigh->dev, dn_neigh_output_packet);
 355 }
 356
 357 /*
 358  * Unfortunately, the neighbour code uses the device in its hash
 359  * function, so we don't get any advantage from it. This function
 360  * basically does a neigh_lookup(), but without comparing the device
 361  * field. This is required for the On-Ethernet cache
 362  */
 363
 364 /*
 365  * Pointopoint link receives a hello message
 366  */
 367 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 368 {
 369         kfree_skb(skb);
 370 }
 371
 372 /*
 373  * Ethernet router hello message received
 374  */
 375 int dn_neigh_router_hello(struct sk_buff *skb)
 376 {
 377         struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 378
 379         struct neighbour *neigh;
 380         struct dn_neigh *dn;
 381         struct dn_dev *dn_db;
 382         __le16 src;
 383
 384         src = dn_eth2dn(msg->id);
 385
 386         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 387
 388         dn = (struct dn_neigh *)neigh;
 389
 390         if (neigh) {
 391                 write_lock(&neigh->lock);
 392
 393                 neigh->used = jiffies;
 394                 dn_db = (struct dn_dev *)neigh->dev->dn_ptr;
 395
 396                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 397                         neigh->updated = jiffies;
 398
 399                         if (neigh->dev->type == ARPHRD_ETHER)
 400                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 401
 402                         dn->blksize  = le16_to_cpu(msg->blksize);
 403                         dn->priority = msg->priority;
 404
 405                         dn->flags &= ~DN_NDFLAG_P3;
 406
 407                         switch(msg->iinfo & DN_RT_INFO_TYPE) {
 408                                 case DN_RT_INFO_L1RT:
 409                                         dn->flags &=~DN_NDFLAG_R2;
 410                                         dn->flags |= DN_NDFLAG_R1;
 411                                         break;
 412                                 case DN_RT_INFO_L2RT:
 413                                         dn->flags |= DN_NDFLAG_R2;
 414                         }
 415                 }
 416
 417                 /* Only use routers in our area */
 418                 if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
 419                         if (!dn_db->router) {
 420                                 dn_db->router = neigh_clone(neigh);
 421                         } else {
 422                                 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 423                                         neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 424                         }
 425                 }
 426                 write_unlock(&neigh->lock);
 427                 neigh_release(neigh);
 428         }
 429
 430         kfree_skb(skb);
 431         return 0;
 432 }
 433
 434 /*
 435  * Endnode hello message received
 436  */
 437 int dn_neigh_endnode_hello(struct sk_buff *skb)
 438 {
 439         struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 440         struct neighbour *neigh;
 441         struct dn_neigh *dn;
 442         __le16 src;
 443
 444         src = dn_eth2dn(msg->id);
 445
 446         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 447
 448         dn = (struct dn_neigh *)neigh;
 449
 450         if (neigh) {
 451                 write_lock(&neigh->lock);
 452
 453                 neigh->used = jiffies;
 454
 455                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 456                         neigh->updated = jiffies;
 457
 458                         if (neigh->dev->type == ARPHRD_ETHER)
 459                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 460                         dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 461                         dn->blksize  = le16_to_cpu(msg->blksize);
 462                         dn->priority = 0;
 463                 }
 464
 465                 write_unlock(&neigh->lock);
 466                 neigh_release(neigh);
 467         }
 468
 469         kfree_skb(skb);
 470         return 0;
 471 }
 472
 473 static char *dn_find_slot(char *base, int max, int priority)
 474 {
 475         int i;
 476         unsigned char *min = NULL;
 477
 478         base += 6; /* skip first id */
 479
 480         for(i = 0; i < max; i++) {
 481                 if (!min || (*base < *min))
 482                         min = base;
 483                 base += 7; /* find next priority */
 484         }
 485
 486         if (!min)
 487                 return NULL;
 488
 489         return (*min < priority) ? (min - 6) : NULL;
 490 }
 491
 492 struct elist_cb_state {
 493         struct net_device *dev;
 494         unsigned char *ptr;
 495         unsigned char *rs;
 496         int t, n;
 497 };
 498
 499 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 500 {
 501         struct elist_cb_state *s = _info;
 502         struct dn_neigh *dn;
 503
 504         if (neigh->dev != s->dev)
 505                 return;
 506
 507         dn = (struct dn_neigh *) neigh;
 508         if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 509                 return;
 510
 511         if (s->t == s->n)
 512                 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 513         else
 514                 s->t++;
 515         if (s->rs == NULL)
 516                 return;
 517
 518         dn_dn2eth(s->rs, dn->addr);
 519         s->rs += 6;
 520         *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 521         *(s->rs) |= dn->priority;
 522         s->rs++;
 523 }
 524
 525 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 526 {
 527         struct elist_cb_state state;
 528
 529         state.dev = dev;
 530         state.t = 0;
 531         state.n = n;
 532         state.ptr = ptr;
 533         state.rs = ptr;
 534
 535         neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 536
 537         return state.t;
 538 }
 539
 540
 541 #ifdef CONFIG_PROC_FS
 542
 543 static inline void dn_neigh_format_entry(struct seq_file *seq,
 544                                          struct neighbour *n)
 545 {
 546         struct dn_neigh *dn = (struct dn_neigh *) n;
 547         char buf[DN_ASCBUF_LEN];
 548
 549         read_lock(&n->lock);
 550         seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 551                    dn_addr2asc(le16_to_cpu(dn->addr), buf),
 552                    (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 553                    (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 554                    (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 555                    dn->n.nud_state,
 556                    atomic_read(&dn->n.refcnt),
 557                    dn->blksize,
 558                    (dn->n.dev) ? dn->n.dev->name : "?");
 559         read_unlock(&n->lock);
 560 }
 561
 562 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 563 {
 564         if (v == SEQ_START_TOKEN) {
 565                 seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 566         } else {
 567                 dn_neigh_format_entry(seq, v);
 568         }
 569
 570         return 0;
 571 }
 572
 573 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 574 {
 575         return neigh_seq_start(seq, pos, &dn_neigh_table,
 576                                NEIGH_SEQ_NEIGH_ONLY);
 577 }
 578
 579 static const struct seq_operations dn_neigh_seq_ops = {
 580         .start = dn_neigh_seq_start,
 581         .next  = neigh_seq_next,
 582         .stop  = neigh_seq_stop,
 583         .show  = dn_neigh_seq_show,
 584 };
 585
 586 static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 587 {
 588         return seq_open_net(inode, file, &dn_neigh_seq_ops,
 589                             sizeof(struct neigh_seq_state));
 590 }
 591
 592 static const struct file_operations dn_neigh_seq_fops = {
 593         .owner          = THIS_MODULE,
 594         .open           = dn_neigh_seq_open,
 595         .read           = seq_read,
 596         .llseek         = seq_lseek,
 597         .release        = seq_release_net,
 598 };
 599
 600 #endif
 601
 602 void __init dn_neigh_init(void)
 603 {
 604         neigh_table_init(&dn_neigh_table);
 605         proc_net_fops_create(&init_net, "decnet_neigh", S_IRUGO, &dn_neigh_seq_fops);
 606 }
 607
 608 void __exit dn_neigh_cleanup(void)
 609 {
 610         proc_net_remove(&init_net, "decnet_neigh");
 611         neigh_table_clear(&dn_neigh_table);
 612 }