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/neighbour.h>
  42 #include <net/dst.h>
  43 #include <net/flow.h>
  44 #include <net/dn.h>
  45 #include <net/dn_dev.h>
  46 #include <net/dn_neigh.h>
  47 #include <net/dn_route.h>
  48
  49 static u32 dn_neigh_hash(const void *pkey, const struct net_device *dev);
  50 static int dn_neigh_construct(struct neighbour *);
  51 static void dn_long_error_report(struct neighbour *, struct sk_buff *);
  52 static void dn_short_error_report(struct neighbour *, struct sk_buff *);
  53 static int dn_long_output(struct sk_buff *);
  54 static int dn_short_output(struct sk_buff *);
  55 static int dn_phase3_output(struct sk_buff *);
  56
  57
  58 /*
  59  * For talking to broadcast devices: Ethernet & PPP
  60  */
  61 static struct neigh_ops dn_long_ops = {
  62         .family =               AF_DECnet,
  63         .error_report =         dn_long_error_report,
  64         .output =               dn_long_output,
  65         .connected_output =     dn_long_output,
  66         .hh_output =            dev_queue_xmit,
  67         .queue_xmit =           dev_queue_xmit,
  68 };
  69
  70 /*
  71  * For talking to pointopoint and multidrop devices: DDCMP and X.25
  72  */
  73 static struct neigh_ops dn_short_ops = {
  74         .family =               AF_DECnet,
  75         .error_report =         dn_short_error_report,
  76         .output =               dn_short_output,
  77         .connected_output =     dn_short_output,
  78         .hh_output =            dev_queue_xmit,
  79         .queue_xmit =           dev_queue_xmit,
  80 };
  81
  82 /*
  83  * For talking to DECnet phase III nodes
  84  */
  85 static struct neigh_ops dn_phase3_ops = {
  86         .family =               AF_DECnet,
  87         .error_report =         dn_short_error_report, /* Can use short version here */
  88         .output =               dn_phase3_output,
  89         .connected_output =     dn_phase3_output,
  90         .hh_output =            dev_queue_xmit,
  91         .queue_xmit =           dev_queue_xmit
  92 };
  93
  94 struct neigh_table dn_neigh_table = {
  95         .family =                       PF_DECnet,
  96         .entry_size =                   sizeof(struct dn_neigh),
  97         .key_len =                      sizeof(__le16),
  98         .hash =                         dn_neigh_hash,
  99         .constructor =                  dn_neigh_construct,
 100         .id =                           "dn_neigh_cache",
 101         .parms ={
 102                 .tbl =                  &dn_neigh_table,
 103                 .base_reachable_time =  30 * HZ,
 104                 .retrans_time = 1 * HZ,
 105                 .gc_staletime = 60 * HZ,
 106                 .reachable_time =               30 * HZ,
 107                 .delay_probe_time =     5 * HZ,
 108                 .queue_len =            3,
 109                 .ucast_probes = 0,
 110                 .app_probes =           0,
 111                 .mcast_probes = 0,
 112                 .anycast_delay =        0,
 113                 .proxy_delay =          0,
 114                 .proxy_qlen =           0,
 115                 .locktime =             1 * HZ,
 116         },
 117         .gc_interval =                  30 * HZ,
 118         .gc_thresh1 =                   128,
 119         .gc_thresh2 =                   512,
 120         .gc_thresh3 =                   1024,
 121 };
 122
 123 static u32 dn_neigh_hash(const void *pkey, const struct net_device *dev)
 124 {
 125         return jhash_2words(*(__u16 *)pkey, 0, dn_neigh_table.hash_rnd);
 126 }
 127
 128 static int dn_neigh_construct(struct neighbour *neigh)
 129 {
 130         struct net_device *dev = neigh->dev;
 131         struct dn_neigh *dn = (struct dn_neigh *)neigh;
 132         struct dn_dev *dn_db;
 133         struct neigh_parms *parms;
 134
 135         rcu_read_lock();
 136         dn_db = rcu_dereference(dev->dn_ptr);
 137         if (dn_db == NULL) {
 138                 rcu_read_unlock();
 139                 return -EINVAL;
 140         }
 141
 142         parms = dn_db->neigh_parms;
 143         if (!parms) {
 144                 rcu_read_unlock();
 145                 return -EINVAL;
 146         }
 147
 148         __neigh_parms_put(neigh->parms);
 149         neigh->parms = neigh_parms_clone(parms);
 150
 151         if (dn_db->use_long)
 152                 neigh->ops = &dn_long_ops;
 153         else
 154                 neigh->ops = &dn_short_ops;
 155         rcu_read_unlock();
 156
 157         if (dn->flags & DN_NDFLAG_P3)
 158                 neigh->ops = &dn_phase3_ops;
 159
 160         neigh->nud_state = NUD_NOARP;
 161         neigh->output = neigh->ops->connected_output;
 162
 163         if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 164                 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 165         else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 166                 dn_dn2eth(neigh->ha, dn->addr);
 167         else {
 168                 if (net_ratelimit())
 169                         printk(KERN_DEBUG "Trying to create neigh for hw %d\n",  dev->type);
 170                 return -EINVAL;
 171         }
 172
 173         /*
 174          * Make an estimate of the remote block size by assuming that its
 175          * two less then the device mtu, which it true for ethernet (and
 176          * other things which support long format headers) since there is
 177          * an extra length field (of 16 bits) which isn't part of the
 178          * ethernet headers and which the DECnet specs won't admit is part
 179          * of the DECnet routing headers either.
 180          *
 181          * If we over estimate here its no big deal, the NSP negotiations
 182          * will prevent us from sending packets which are too large for the
 183          * remote node to handle. In any case this figure is normally updated
 184          * by a hello message in most cases.
 185          */
 186         dn->blksize = dev->mtu - 2;
 187
 188         return 0;
 189 }
 190
 191 static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
 192 {
 193         printk(KERN_DEBUG "dn_long_error_report: called\n");
 194         kfree_skb(skb);
 195 }
 196
 197
 198 static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
 199 {
 200         printk(KERN_DEBUG "dn_short_error_report: called\n");
 201         kfree_skb(skb);
 202 }
 203
 204 static int dn_neigh_output_packet(struct sk_buff *skb)
 205 {
 206         struct dst_entry *dst = skb->dst;
 207         struct dn_route *rt = (struct dn_route *)dst;
 208         struct neighbour *neigh = dst->neighbour;
 209         struct net_device *dev = neigh->dev;
 210         char mac_addr[ETH_ALEN];
 211
 212         dn_dn2eth(mac_addr, rt->rt_local_src);
 213         if (!dev->hard_header || dev->hard_header(skb, dev, ntohs(skb->protocol), neigh->ha, mac_addr, skb->len) >= 0)
 214                 return neigh->ops->queue_xmit(skb);
 215
 216         if (net_ratelimit())
 217                 printk(KERN_DEBUG "dn_neigh_output_packet: oops, can't send packet\n");
 218
 219         kfree_skb(skb);
 220         return -EINVAL;
 221 }
 222
 223 static int dn_long_output(struct sk_buff *skb)
 224 {
 225         struct dst_entry *dst = skb->dst;
 226         struct neighbour *neigh = dst->neighbour;
 227         struct net_device *dev = neigh->dev;
 228         int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
 229         unsigned char *data;
 230         struct dn_long_packet *lp;
 231         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 232
 233
 234         if (skb_headroom(skb) < headroom) {
 235                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 236                 if (skb2 == NULL) {
 237                         if (net_ratelimit())
 238                                 printk(KERN_CRIT "dn_long_output: no memory\n");
 239                         kfree_skb(skb);
 240                         return -ENOBUFS;
 241                 }
 242                 kfree_skb(skb);
 243                 skb = skb2;
 244                 if (net_ratelimit())
 245                         printk(KERN_INFO "dn_long_output: Increasing headroom\n");
 246         }
 247
 248         data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
 249         lp = (struct dn_long_packet *)(data+3);
 250
 251         *((__le16 *)data) = dn_htons(skb->len - 2);
 252         *(data + 2) = 1 | DN_RT_F_PF; /* Padding */
 253
 254         lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
 255         lp->d_area   = lp->d_subarea = 0;
 256         dn_dn2eth(lp->d_id, cb->dst);
 257         lp->s_area   = lp->s_subarea = 0;
 258         dn_dn2eth(lp->s_id, cb->src);
 259         lp->nl2      = 0;
 260         lp->visit_ct = cb->hops & 0x3f;
 261         lp->s_class  = 0;
 262         lp->pt       = 0;
 263
 264         skb_reset_network_header(skb);
 265
 266         return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 267 }
 268
 269 static int dn_short_output(struct sk_buff *skb)
 270 {
 271         struct dst_entry *dst = skb->dst;
 272         struct neighbour *neigh = dst->neighbour;
 273         struct net_device *dev = neigh->dev;
 274         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 275         struct dn_short_packet *sp;
 276         unsigned char *data;
 277         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 278
 279
 280         if (skb_headroom(skb) < headroom) {
 281                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 282                 if (skb2 == NULL) {
 283                         if (net_ratelimit())
 284                                 printk(KERN_CRIT "dn_short_output: no memory\n");
 285                         kfree_skb(skb);
 286                         return -ENOBUFS;
 287                 }
 288                 kfree_skb(skb);
 289                 skb = skb2;
 290                 if (net_ratelimit())
 291                         printk(KERN_INFO "dn_short_output: Increasing headroom\n");
 292         }
 293
 294         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 295         *((__le16 *)data) = dn_htons(skb->len - 2);
 296         sp = (struct dn_short_packet *)(data+2);
 297
 298         sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 299         sp->dstnode    = cb->dst;
 300         sp->srcnode    = cb->src;
 301         sp->forward    = cb->hops & 0x3f;
 302
 303         skb_reset_network_header(skb);
 304
 305         return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 306 }
 307
 308 /*
 309  * Phase 3 output is the same is short output, execpt that
 310  * it clears the area bits before transmission.
 311  */
 312 static int dn_phase3_output(struct sk_buff *skb)
 313 {
 314         struct dst_entry *dst = skb->dst;
 315         struct neighbour *neigh = dst->neighbour;
 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) = dn_htons(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 & dn_htons(0x03ff);
 342         sp->srcnode  = cb->src & dn_htons(0x03ff);
 343         sp->forward  = cb->hops & 0x3f;
 344
 345         skb_reset_network_header(skb);
 346
 347         return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 348 }
 349
 350 /*
 351  * Unfortunately, the neighbour code uses the device in its hash
 352  * function, so we don't get any advantage from it. This function
 353  * basically does a neigh_lookup(), but without comparing the device
 354  * field. This is required for the On-Ethernet cache
 355  */
 356
 357 /*
 358  * Pointopoint link receives a hello message
 359  */
 360 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 361 {
 362         kfree_skb(skb);
 363 }
 364
 365 /*
 366  * Ethernet router hello message received
 367  */
 368 int dn_neigh_router_hello(struct sk_buff *skb)
 369 {
 370         struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 371
 372         struct neighbour *neigh;
 373         struct dn_neigh *dn;
 374         struct dn_dev *dn_db;
 375         __le16 src;
 376
 377         src = dn_eth2dn(msg->id);
 378
 379         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 380
 381         dn = (struct dn_neigh *)neigh;
 382
 383         if (neigh) {
 384                 write_lock(&neigh->lock);
 385
 386                 neigh->used = jiffies;
 387                 dn_db = (struct dn_dev *)neigh->dev->dn_ptr;
 388
 389                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 390                         neigh->updated = jiffies;
 391
 392                         if (neigh->dev->type == ARPHRD_ETHER)
 393                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 394
 395                         dn->blksize  = dn_ntohs(msg->blksize);
 396                         dn->priority = msg->priority;
 397
 398                         dn->flags &= ~DN_NDFLAG_P3;
 399
 400                         switch(msg->iinfo & DN_RT_INFO_TYPE) {
 401                                 case DN_RT_INFO_L1RT:
 402                                         dn->flags &=~DN_NDFLAG_R2;
 403                                         dn->flags |= DN_NDFLAG_R1;
 404                                         break;
 405                                 case DN_RT_INFO_L2RT:
 406                                         dn->flags |= DN_NDFLAG_R2;
 407                         }
 408                 }
 409
 410                 /* Only use routers in our area */
 411                 if ((dn_ntohs(src)>>10) == (dn_ntohs((decnet_address))>>10)) {
 412                         if (!dn_db->router) {
 413                                 dn_db->router = neigh_clone(neigh);
 414                         } else {
 415                                 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 416                                         neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 417                         }
 418                 }
 419                 write_unlock(&neigh->lock);
 420                 neigh_release(neigh);
 421         }
 422
 423         kfree_skb(skb);
 424         return 0;
 425 }
 426
 427 /*
 428  * Endnode hello message received
 429  */
 430 int dn_neigh_endnode_hello(struct sk_buff *skb)
 431 {
 432         struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 433         struct neighbour *neigh;
 434         struct dn_neigh *dn;
 435         __le16 src;
 436
 437         src = dn_eth2dn(msg->id);
 438
 439         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 440
 441         dn = (struct dn_neigh *)neigh;
 442
 443         if (neigh) {
 444                 write_lock(&neigh->lock);
 445
 446                 neigh->used = jiffies;
 447
 448                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 449                         neigh->updated = jiffies;
 450
 451                         if (neigh->dev->type == ARPHRD_ETHER)
 452                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 453                         dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 454                         dn->blksize  = dn_ntohs(msg->blksize);
 455                         dn->priority = 0;
 456                 }
 457
 458                 write_unlock(&neigh->lock);
 459                 neigh_release(neigh);
 460         }
 461
 462         kfree_skb(skb);
 463         return 0;
 464 }
 465
 466 static char *dn_find_slot(char *base, int max, int priority)
 467 {
 468         int i;
 469         unsigned char *min = NULL;
 470
 471         base += 6; /* skip first id */
 472
 473         for(i = 0; i < max; i++) {
 474                 if (!min || (*base < *min))
 475                         min = base;
 476                 base += 7; /* find next priority */
 477         }
 478
 479         if (!min)
 480                 return NULL;
 481
 482         return (*min < priority) ? (min - 6) : NULL;
 483 }
 484
 485 struct elist_cb_state {
 486         struct net_device *dev;
 487         unsigned char *ptr;
 488         unsigned char *rs;
 489         int t, n;
 490 };
 491
 492 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 493 {
 494         struct elist_cb_state *s = _info;
 495         struct dn_neigh *dn;
 496
 497         if (neigh->dev != s->dev)
 498                 return;
 499
 500         dn = (struct dn_neigh *) neigh;
 501         if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 502                 return;
 503
 504         if (s->t == s->n)
 505                 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 506         else
 507                 s->t++;
 508         if (s->rs == NULL)
 509                 return;
 510
 511         dn_dn2eth(s->rs, dn->addr);
 512         s->rs += 6;
 513         *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 514         *(s->rs) |= dn->priority;
 515         s->rs++;
 516 }
 517
 518 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 519 {
 520         struct elist_cb_state state;
 521
 522         state.dev = dev;
 523         state.t = 0;
 524         state.n = n;
 525         state.ptr = ptr;
 526         state.rs = ptr;
 527
 528         neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 529
 530         return state.t;
 531 }
 532
 533
 534 #ifdef CONFIG_PROC_FS
 535
 536 static inline void dn_neigh_format_entry(struct seq_file *seq,
 537                                          struct neighbour *n)
 538 {
 539         struct dn_neigh *dn = (struct dn_neigh *) n;
 540         char buf[DN_ASCBUF_LEN];
 541
 542         read_lock(&n->lock);
 543         seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 544                    dn_addr2asc(dn_ntohs(dn->addr), buf),
 545                    (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 546                    (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 547                    (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 548                    dn->n.nud_state,
 549                    atomic_read(&dn->n.refcnt),
 550                    dn->blksize,
 551                    (dn->n.dev) ? dn->n.dev->name : "?");
 552         read_unlock(&n->lock);
 553 }
 554
 555 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 556 {
 557         if (v == SEQ_START_TOKEN) {
 558                 seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 559         } else {
 560                 dn_neigh_format_entry(seq, v);
 561         }
 562
 563         return 0;
 564 }
 565
 566 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 567 {
 568         return neigh_seq_start(seq, pos, &dn_neigh_table,
 569                                NEIGH_SEQ_NEIGH_ONLY);
 570 }
 571
 572 static struct seq_operations dn_neigh_seq_ops = {
 573         .start = dn_neigh_seq_start,
 574         .next  = neigh_seq_next,
 575         .stop  = neigh_seq_stop,
 576         .show  = dn_neigh_seq_show,
 577 };
 578
 579 static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 580 {
 581         struct seq_file *seq;
 582         int rc = -ENOMEM;
 583         struct neigh_seq_state *s = kzalloc(sizeof(*s), GFP_KERNEL);
 584
 585         if (!s)
 586                 goto out;
 587
 588         rc = seq_open(file, &dn_neigh_seq_ops);
 589         if (rc)
 590                 goto out_kfree;
 591
 592         seq          = file->private_data;
 593         seq->private = s;
 594 out:
 595         return rc;
 596 out_kfree:
 597         kfree(s);
 598         goto out;
 599 }
 600
 601 static const struct file_operations dn_neigh_seq_fops = {
 602         .owner          = THIS_MODULE,
 603         .open           = dn_neigh_seq_open,
 604         .read           = seq_read,
 605         .llseek         = seq_lseek,
 606         .release        = seq_release_private,
 607 };
 608
 609 #endif
 610
 611 void __init dn_neigh_init(void)
 612 {
 613         neigh_table_init(&dn_neigh_table);
 614         proc_net_fops_create("decnet_neigh", S_IRUGO, &dn_neigh_seq_fops);
 615 }
 616
 617 void __exit dn_neigh_cleanup(void)
 618 {
 619         proc_net_remove("decnet_neigh");
 620         neigh_table_clear(&dn_neigh_table);
 621 }