net/decnet/dn_route.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 Routing Functions (Endnode and Router)
   7  *
   8  * Authors:     Steve Whitehouse <SteveW@ACM.org>
   9  *              Eduardo Marcelo Serrat <emserrat@geocities.com>
  10  *
  11  * Changes:
  12  *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
  13  *                                 "return-to-sender" bits on outgoing
  14  *                                 packets.
  15  *              Steve Whitehouse : Timeouts for cached routes.
  16  *              Steve Whitehouse : Use dst cache for input routes too.
  17  *              Steve Whitehouse : Fixed error values in dn_send_skb.
  18  *              Steve Whitehouse : Rework routing functions to better fit
  19  *                                 DECnet routing design
  20  *              Alexey Kuznetsov : New SMP locking
  21  *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
  22  *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
  23  *                                 Fixed possible skb leak in rtnetlink funcs.
  24  *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
  25  *                                 Alexey Kuznetsov's finer grained locking
  26  *                                 from ipv4/route.c.
  27  *              Steve Whitehouse : Routing is now starting to look like a
  28  *                                 sensible set of code now, mainly due to
  29  *                                 my copying the IPv4 routing code. The
  30  *                                 hooks here are modified and will continue
  31  *                                 to evolve for a while.
  32  *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
  33  *                                 stuff. Look out raw sockets your days
  34  *                                 are numbered!
  35  *              Steve Whitehouse : Added return-to-sender functions. Added
  36  *                                 backlog congestion level return codes.
  37  *              Steve Whitehouse : Fixed bug where routes were set up with
  38  *                                 no ref count on net devices.
  39  *              Steve Whitehouse : RCU for the route cache
  40  *              Steve Whitehouse : Preparations for the flow cache
  41  *              Steve Whitehouse : Prepare for nonlinear skbs
  42  */
  43
  44 /******************************************************************************
  45     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
  46
  47     This program is free software; you can redistribute it and/or modify
  48     it under the terms of the GNU General Public License as published by
  49     the Free Software Foundation; either version 2 of the License, or
  50     any later version.
  51
  52     This program is distributed in the hope that it will be useful,
  53     but WITHOUT ANY WARRANTY; without even the implied warranty of
  54     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  55     GNU General Public License for more details.
  56 *******************************************************************************/
  57
  58 #include <linux/errno.h>
  59 #include <linux/types.h>
  60 #include <linux/socket.h>
  61 #include <linux/in.h>
  62 #include <linux/kernel.h>
  63 #include <linux/sockios.h>
  64 #include <linux/net.h>
  65 #include <linux/netdevice.h>
  66 #include <linux/inet.h>
  67 #include <linux/route.h>
  68 #include <linux/in_route.h>
  69 #include <linux/slab.h>
  70 #include <net/sock.h>
  71 #include <linux/mm.h>
  72 #include <linux/proc_fs.h>
  73 #include <linux/seq_file.h>
  74 #include <linux/init.h>
  75 #include <linux/rtnetlink.h>
  76 #include <linux/string.h>
  77 #include <linux/netfilter_decnet.h>
  78 #include <linux/rcupdate.h>
  79 #include <linux/times.h>
  80 #include <linux/export.h>
  81 #include <asm/errno.h>
  82 #include <net/net_namespace.h>
  83 #include <net/netlink.h>
  84 #include <net/neighbour.h>
  85 #include <net/dst.h>
  86 #include <net/flow.h>
  87 #include <net/fib_rules.h>
  88 #include <net/dn.h>
  89 #include <net/dn_dev.h>
  90 #include <net/dn_nsp.h>
  91 #include <net/dn_route.h>
  92 #include <net/dn_neigh.h>
  93 #include <net/dn_fib.h>
  94
  95 struct dn_rt_hash_bucket
  96 {
  97         struct dn_route __rcu *chain;
  98         spinlock_t lock;
  99 };
 100
 101 extern struct neigh_table dn_neigh_table;
 102
 103
 104 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 105
 106 static const int dn_rt_min_delay = 2 * HZ;
 107 static const int dn_rt_max_delay = 10 * HZ;
 108 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 109
 110 static unsigned long dn_rt_deadline;
 111
 112 static int dn_dst_gc(struct dst_ops *ops);
 113 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 114 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst);
 115 static unsigned int dn_dst_mtu(const struct dst_entry *dst);
 116 static void dn_dst_destroy(struct dst_entry *);
 117 static void dn_dst_ifdown(struct dst_entry *, struct net_device *dev, int how);
 118 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 119 static void dn_dst_link_failure(struct sk_buff *);
 120 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
 121                                struct sk_buff *skb , u32 mtu);
 122 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
 123                             struct sk_buff *skb);
 124 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
 125                                              struct sk_buff *skb,
 126                                              const void *daddr);
 127 static int dn_route_input(struct sk_buff *);
 128 static void dn_run_flush(unsigned long dummy);
 129
 130 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 131 static unsigned int dn_rt_hash_mask;
 132
 133 static struct timer_list dn_route_timer;
 134 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 135 int decnet_dst_gc_interval = 2;
 136
 137 static struct dst_ops dn_dst_ops = {
 138         .family =               PF_DECnet,
 139         .protocol =             cpu_to_be16(ETH_P_DNA_RT),
 140         .gc_thresh =            128,
 141         .gc =                   dn_dst_gc,
 142         .check =                dn_dst_check,
 143         .default_advmss =       dn_dst_default_advmss,
 144         .mtu =                  dn_dst_mtu,
 145         .cow_metrics =          dst_cow_metrics_generic,
 146         .destroy =              dn_dst_destroy,
 147         .ifdown =               dn_dst_ifdown,
 148         .negative_advice =      dn_dst_negative_advice,
 149         .link_failure =         dn_dst_link_failure,
 150         .update_pmtu =          dn_dst_update_pmtu,
 151         .redirect =             dn_dst_redirect,
 152         .neigh_lookup =         dn_dst_neigh_lookup,
 153 };
 154
 155 static void dn_dst_destroy(struct dst_entry *dst)
 156 {
 157         struct dn_route *rt = (struct dn_route *) dst;
 158
 159         if (rt->n)
 160                 neigh_release(rt->n);
 161         dst_destroy_metrics_generic(dst);
 162 }
 163
 164 static void dn_dst_ifdown(struct dst_entry *dst, struct net_device *dev, int how)
 165 {
 166         if (how) {
 167                 struct dn_route *rt = (struct dn_route *) dst;
 168                 struct neighbour *n = rt->n;
 169
 170                 if (n && n->dev == dev) {
 171                         n->dev = dev_net(dev)->loopback_dev;
 172                         dev_hold(n->dev);
 173                         dev_put(dev);
 174                 }
 175         }
 176 }
 177
 178 static __inline__ unsigned int dn_hash(__le16 src, __le16 dst)
 179 {
 180         __u16 tmp = (__u16 __force)(src ^ dst);
 181         tmp ^= (tmp >> 3);
 182         tmp ^= (tmp >> 5);
 183         tmp ^= (tmp >> 10);
 184         return dn_rt_hash_mask & (unsigned int)tmp;
 185 }
 186
 187 static inline void dnrt_free(struct dn_route *rt)
 188 {
 189         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 190 }
 191
 192 static inline void dnrt_drop(struct dn_route *rt)
 193 {
 194         dst_release(&rt->dst);
 195         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 196 }
 197
 198 static void dn_dst_check_expire(unsigned long dummy)
 199 {
 200         int i;
 201         struct dn_route *rt;
 202         struct dn_route __rcu **rtp;
 203         unsigned long now = jiffies;
 204         unsigned long expire = 120 * HZ;
 205
 206         for (i = 0; i <= dn_rt_hash_mask; i++) {
 207                 rtp = &dn_rt_hash_table[i].chain;
 208
 209                 spin_lock(&dn_rt_hash_table[i].lock);
 210                 while ((rt = rcu_dereference_protected(*rtp,
 211                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 212                         if (atomic_read(&rt->dst.__refcnt) ||
 213                                         (now - rt->dst.lastuse) < expire) {
 214                                 rtp = &rt->dst.dn_next;
 215                                 continue;
 216                         }
 217                         *rtp = rt->dst.dn_next;
 218                         rt->dst.dn_next = NULL;
 219                         dnrt_free(rt);
 220                 }
 221                 spin_unlock(&dn_rt_hash_table[i].lock);
 222
 223                 if ((jiffies - now) > 0)
 224                         break;
 225         }
 226
 227         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 228 }
 229
 230 static int dn_dst_gc(struct dst_ops *ops)
 231 {
 232         struct dn_route *rt;
 233         struct dn_route __rcu **rtp;
 234         int i;
 235         unsigned long now = jiffies;
 236         unsigned long expire = 10 * HZ;
 237
 238         for (i = 0; i <= dn_rt_hash_mask; i++) {
 239
 240                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 241                 rtp = &dn_rt_hash_table[i].chain;
 242
 243                 while ((rt = rcu_dereference_protected(*rtp,
 244                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 245                         if (atomic_read(&rt->dst.__refcnt) ||
 246                                         (now - rt->dst.lastuse) < expire) {
 247                                 rtp = &rt->dst.dn_next;
 248                                 continue;
 249                         }
 250                         *rtp = rt->dst.dn_next;
 251                         rt->dst.dn_next = NULL;
 252                         dnrt_drop(rt);
 253                         break;
 254                 }
 255                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 256         }
 257
 258         return 0;
 259 }
 260
 261 /*
 262  * The decnet standards don't impose a particular minimum mtu, what they
 263  * do insist on is that the routing layer accepts a datagram of at least
 264  * 230 bytes long. Here we have to subtract the routing header length from
 265  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 266  * assume the worst and use a long header size.
 267  *
 268  * We update both the mtu and the advertised mss (i.e. the segment size we
 269  * advertise to the other end).
 270  */
 271 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
 272                                struct sk_buff *skb, u32 mtu)
 273 {
 274         struct dn_route *rt = (struct dn_route *) dst;
 275         struct neighbour *n = rt->n;
 276         u32 min_mtu = 230;
 277         struct dn_dev *dn;
 278
 279         dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL;
 280
 281         if (dn && dn->use_long == 0)
 282                 min_mtu -= 6;
 283         else
 284                 min_mtu -= 21;
 285
 286         if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
 287                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
 288                         dst_metric_set(dst, RTAX_MTU, mtu);
 289                         dst_set_expires(dst, dn_rt_mtu_expires);
 290                 }
 291                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 292                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 293                         u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
 294                         if (!existing_mss || existing_mss > mss)
 295                                 dst_metric_set(dst, RTAX_ADVMSS, mss);
 296                 }
 297         }
 298 }
 299
 300 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
 301                             struct sk_buff *skb)
 302 {
 303 }
 304
 305 /*
 306  * When a route has been marked obsolete. (e.g. routing cache flush)
 307  */
 308 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 309 {
 310         return NULL;
 311 }
 312
 313 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 314 {
 315         dst_release(dst);
 316         return NULL;
 317 }
 318
 319 static void dn_dst_link_failure(struct sk_buff *skb)
 320 {
 321 }
 322
 323 static inline int compare_keys(struct flowidn *fl1, struct flowidn *fl2)
 324 {
 325         return ((fl1->daddr ^ fl2->daddr) |
 326                 (fl1->saddr ^ fl2->saddr) |
 327                 (fl1->flowidn_mark ^ fl2->flowidn_mark) |
 328                 (fl1->flowidn_scope ^ fl2->flowidn_scope) |
 329                 (fl1->flowidn_oif ^ fl2->flowidn_oif) |
 330                 (fl1->flowidn_iif ^ fl2->flowidn_iif)) == 0;
 331 }
 332
 333 static int dn_insert_route(struct dn_route *rt, unsigned int hash, struct dn_route **rp)
 334 {
 335         struct dn_route *rth;
 336         struct dn_route __rcu **rthp;
 337         unsigned long now = jiffies;
 338
 339         rthp = &dn_rt_hash_table[hash].chain;
 340
 341         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 342         while ((rth = rcu_dereference_protected(*rthp,
 343                                                 lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
 344                 if (compare_keys(&rth->fld, &rt->fld)) {
 345                         /* Put it first */
 346                         *rthp = rth->dst.dn_next;
 347                         rcu_assign_pointer(rth->dst.dn_next,
 348                                            dn_rt_hash_table[hash].chain);
 349                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 350
 351                         dst_use(&rth->dst, now);
 352                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 353
 354                         dnrt_drop(rt);
 355                         *rp = rth;
 356                         return 0;
 357                 }
 358                 rthp = &rth->dst.dn_next;
 359         }
 360
 361         rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain);
 362         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 363
 364         dst_use(&rt->dst, now);
 365         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 366         *rp = rt;
 367         return 0;
 368 }
 369
 370 static void dn_run_flush(unsigned long dummy)
 371 {
 372         int i;
 373         struct dn_route *rt, *next;
 374
 375         for (i = 0; i < dn_rt_hash_mask; i++) {
 376                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 377
 378                 if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
 379                         goto nothing_to_declare;
 380
 381                 for(; rt; rt = next) {
 382                         next = rcu_dereference_raw(rt->dst.dn_next);
 383                         RCU_INIT_POINTER(rt->dst.dn_next, NULL);
 384                         dst_free((struct dst_entry *)rt);
 385                 }
 386
 387 nothing_to_declare:
 388                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 389         }
 390 }
 391
 392 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 393
 394 void dn_rt_cache_flush(int delay)
 395 {
 396         unsigned long now = jiffies;
 397         int user_mode = !in_interrupt();
 398
 399         if (delay < 0)
 400                 delay = dn_rt_min_delay;
 401
 402         spin_lock_bh(&dn_rt_flush_lock);
 403
 404         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 405                 long tmo = (long)(dn_rt_deadline - now);
 406
 407                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 408                         tmo = 0;
 409
 410                 if (delay > tmo)
 411                         delay = tmo;
 412         }
 413
 414         if (delay <= 0) {
 415                 spin_unlock_bh(&dn_rt_flush_lock);
 416                 dn_run_flush(0);
 417                 return;
 418         }
 419
 420         if (dn_rt_deadline == 0)
 421                 dn_rt_deadline = now + dn_rt_max_delay;
 422
 423         dn_rt_flush_timer.expires = now + delay;
 424         add_timer(&dn_rt_flush_timer);
 425         spin_unlock_bh(&dn_rt_flush_lock);
 426 }
 427
 428 /**
 429  * dn_return_short - Return a short packet to its sender
 430  * @skb: The packet to return
 431  *
 432  */
 433 static int dn_return_short(struct sk_buff *skb)
 434 {
 435         struct dn_skb_cb *cb;
 436         unsigned char *ptr;
 437         __le16 *src;
 438         __le16 *dst;
 439
 440         /* Add back headers */
 441         skb_push(skb, skb->data - skb_network_header(skb));
 442
 443         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 444                 return NET_RX_DROP;
 445
 446         cb = DN_SKB_CB(skb);
 447         /* Skip packet length and point to flags */
 448         ptr = skb->data + 2;
 449         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 450
 451         dst = (__le16 *)ptr;
 452         ptr += 2;
 453         src = (__le16 *)ptr;
 454         ptr += 2;
 455         *ptr = 0; /* Zero hop count */
 456
 457         swap(*src, *dst);
 458
 459         skb->pkt_type = PACKET_OUTGOING;
 460         dn_rt_finish_output(skb, NULL, NULL);
 461         return NET_RX_SUCCESS;
 462 }
 463
 464 /**
 465  * dn_return_long - Return a long packet to its sender
 466  * @skb: The long format packet to return
 467  *
 468  */
 469 static int dn_return_long(struct sk_buff *skb)
 470 {
 471         struct dn_skb_cb *cb;
 472         unsigned char *ptr;
 473         unsigned char *src_addr, *dst_addr;
 474         unsigned char tmp[ETH_ALEN];
 475
 476         /* Add back all headers */
 477         skb_push(skb, skb->data - skb_network_header(skb));
 478
 479         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 480                 return NET_RX_DROP;
 481
 482         cb = DN_SKB_CB(skb);
 483         /* Ignore packet length and point to flags */
 484         ptr = skb->data + 2;
 485
 486         /* Skip padding */
 487         if (*ptr & DN_RT_F_PF) {
 488                 char padlen = (*ptr & ~DN_RT_F_PF);
 489                 ptr += padlen;
 490         }
 491
 492         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 493         ptr += 2;
 494         dst_addr = ptr;
 495         ptr += 8;
 496         src_addr = ptr;
 497         ptr += 6;
 498         *ptr = 0; /* Zero hop count */
 499
 500         /* Swap source and destination */
 501         memcpy(tmp, src_addr, ETH_ALEN);
 502         memcpy(src_addr, dst_addr, ETH_ALEN);
 503         memcpy(dst_addr, tmp, ETH_ALEN);
 504
 505         skb->pkt_type = PACKET_OUTGOING;
 506         dn_rt_finish_output(skb, dst_addr, src_addr);
 507         return NET_RX_SUCCESS;
 508 }
 509
 510 /**
 511  * dn_route_rx_packet - Try and find a route for an incoming packet
 512  * @skb: The packet to find a route for
 513  *
 514  * Returns: result of input function if route is found, error code otherwise
 515  */
 516 static int dn_route_rx_packet(struct sk_buff *skb)
 517 {
 518         struct dn_skb_cb *cb;
 519         int err;
 520
 521         if ((err = dn_route_input(skb)) == 0)
 522                 return dst_input(skb);
 523
 524         cb = DN_SKB_CB(skb);
 525         if (decnet_debug_level & 4) {
 526                 char *devname = skb->dev ? skb->dev->name : "???";
 527
 528                 printk(KERN_DEBUG
 529                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 530                         (int)cb->rt_flags, devname, skb->len,
 531                         le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
 532                         err, skb->pkt_type);
 533         }
 534
 535         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 536                 switch (cb->rt_flags & DN_RT_PKT_MSK) {
 537                 case DN_RT_PKT_SHORT:
 538                         return dn_return_short(skb);
 539                 case DN_RT_PKT_LONG:
 540                         return dn_return_long(skb);
 541                 }
 542         }
 543
 544         kfree_skb(skb);
 545         return NET_RX_DROP;
 546 }
 547
 548 static int dn_route_rx_long(struct sk_buff *skb)
 549 {
 550         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 551         unsigned char *ptr = skb->data;
 552
 553         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 554                 goto drop_it;
 555
 556         skb_pull(skb, 20);
 557         skb_reset_transport_header(skb);
 558
 559         /* Destination info */
 560         ptr += 2;
 561         cb->dst = dn_eth2dn(ptr);
 562         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 563                 goto drop_it;
 564         ptr += 6;
 565
 566
 567         /* Source info */
 568         ptr += 2;
 569         cb->src = dn_eth2dn(ptr);
 570         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 571                 goto drop_it;
 572         ptr += 6;
 573         /* Other junk */
 574         ptr++;
 575         cb->hops = *ptr++; /* Visit Count */
 576
 577         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 578                        dn_route_rx_packet);
 579
 580 drop_it:
 581         kfree_skb(skb);
 582         return NET_RX_DROP;
 583 }
 584
 585
 586
 587 static int dn_route_rx_short(struct sk_buff *skb)
 588 {
 589         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 590         unsigned char *ptr = skb->data;
 591
 592         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 593                 goto drop_it;
 594
 595         skb_pull(skb, 5);
 596         skb_reset_transport_header(skb);
 597
 598         cb->dst = *(__le16 *)ptr;
 599         ptr += 2;
 600         cb->src = *(__le16 *)ptr;
 601         ptr += 2;
 602         cb->hops = *ptr & 0x3f;
 603
 604         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 605                        dn_route_rx_packet);
 606
 607 drop_it:
 608         kfree_skb(skb);
 609         return NET_RX_DROP;
 610 }
 611
 612 static int dn_route_discard(struct sk_buff *skb)
 613 {
 614         /*
 615          * I know we drop the packet here, but thats considered success in
 616          * this case
 617          */
 618         kfree_skb(skb);
 619         return NET_RX_SUCCESS;
 620 }
 621
 622 static int dn_route_ptp_hello(struct sk_buff *skb)
 623 {
 624         dn_dev_hello(skb);
 625         dn_neigh_pointopoint_hello(skb);
 626         return NET_RX_SUCCESS;
 627 }
 628
 629 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 630 {
 631         struct dn_skb_cb *cb;
 632         unsigned char flags = 0;
 633         __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 634         struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
 635         unsigned char padlen = 0;
 636
 637         if (!net_eq(dev_net(dev), &init_net))
 638                 goto dump_it;
 639
 640         if (dn == NULL)
 641                 goto dump_it;
 642
 643         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 644                 goto out;
 645
 646         if (!pskb_may_pull(skb, 3))
 647                 goto dump_it;
 648
 649         skb_pull(skb, 2);
 650
 651         if (len > skb->len)
 652                 goto dump_it;
 653
 654         skb_trim(skb, len);
 655
 656         flags = *skb->data;
 657
 658         cb = DN_SKB_CB(skb);
 659         cb->stamp = jiffies;
 660         cb->iif = dev->ifindex;
 661
 662         /*
 663          * If we have padding, remove it.
 664          */
 665         if (flags & DN_RT_F_PF) {
 666                 padlen = flags & ~DN_RT_F_PF;
 667                 if (!pskb_may_pull(skb, padlen + 1))
 668                         goto dump_it;
 669                 skb_pull(skb, padlen);
 670                 flags = *skb->data;
 671         }
 672
 673         skb_reset_network_header(skb);
 674
 675         /*
 676          * Weed out future version DECnet
 677          */
 678         if (flags & DN_RT_F_VER)
 679                 goto dump_it;
 680
 681         cb->rt_flags = flags;
 682
 683         if (decnet_debug_level & 1)
 684                 printk(KERN_DEBUG
 685                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 686                         (int)flags, (dev) ? dev->name : "???", len, skb->len,
 687                         padlen);
 688
 689         if (flags & DN_RT_PKT_CNTL) {
 690                 if (unlikely(skb_linearize(skb)))
 691                         goto dump_it;
 692
 693                 switch (flags & DN_RT_CNTL_MSK) {
 694                 case DN_RT_PKT_INIT:
 695                         dn_dev_init_pkt(skb);
 696                         break;
 697                 case DN_RT_PKT_VERI:
 698                         dn_dev_veri_pkt(skb);
 699                         break;
 700                 }
 701
 702                 if (dn->parms.state != DN_DEV_S_RU)
 703                         goto dump_it;
 704
 705                 switch (flags & DN_RT_CNTL_MSK) {
 706                 case DN_RT_PKT_HELO:
 707                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 708                                        skb, skb->dev, NULL,
 709                                        dn_route_ptp_hello);
 710
 711                 case DN_RT_PKT_L1RT:
 712                 case DN_RT_PKT_L2RT:
 713                         return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
 714                                        skb, skb->dev, NULL,
 715                                        dn_route_discard);
 716                 case DN_RT_PKT_ERTH:
 717                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 718                                        skb, skb->dev, NULL,
 719                                        dn_neigh_router_hello);
 720
 721                 case DN_RT_PKT_EEDH:
 722                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 723                                        skb, skb->dev, NULL,
 724                                        dn_neigh_endnode_hello);
 725                 }
 726         } else {
 727                 if (dn->parms.state != DN_DEV_S_RU)
 728                         goto dump_it;
 729
 730                 skb_pull(skb, 1); /* Pull flags */
 731
 732                 switch (flags & DN_RT_PKT_MSK) {
 733                 case DN_RT_PKT_LONG:
 734                         return dn_route_rx_long(skb);
 735                 case DN_RT_PKT_SHORT:
 736                         return dn_route_rx_short(skb);
 737                 }
 738         }
 739
 740 dump_it:
 741         kfree_skb(skb);
 742 out:
 743         return NET_RX_DROP;
 744 }
 745
 746 static int dn_output(struct sock *sk, struct sk_buff *skb)
 747 {
 748         struct dst_entry *dst = skb_dst(skb);
 749         struct dn_route *rt = (struct dn_route *)dst;
 750         struct net_device *dev = dst->dev;
 751         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 752
 753         int err = -EINVAL;
 754
 755         if (rt->n == NULL)
 756                 goto error;
 757
 758         skb->dev = dev;
 759
 760         cb->src = rt->rt_saddr;
 761         cb->dst = rt->rt_daddr;
 762
 763         /*
 764          * Always set the Intra-Ethernet bit on all outgoing packets
 765          * originated on this node. Only valid flag from upper layers
 766          * is return-to-sender-requested. Set hop count to 0 too.
 767          */
 768         cb->rt_flags &= ~DN_RT_F_RQR;
 769         cb->rt_flags |= DN_RT_F_IE;
 770         cb->hops = 0;
 771
 772         return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, skb, NULL, dev,
 773                        dn_to_neigh_output);
 774
 775 error:
 776         net_dbg_ratelimited("dn_output: This should not happen\n");
 777
 778         kfree_skb(skb);
 779
 780         return err;
 781 }
 782
 783 static int dn_forward(struct sk_buff *skb)
 784 {
 785         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 786         struct dst_entry *dst = skb_dst(skb);
 787         struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
 788         struct dn_route *rt;
 789         int header_len;
 790 #ifdef CONFIG_NETFILTER
 791         struct net_device *dev = skb->dev;
 792 #endif
 793
 794         if (skb->pkt_type != PACKET_HOST)
 795                 goto drop;
 796
 797         /* Ensure that we have enough space for headers */
 798         rt = (struct dn_route *)skb_dst(skb);
 799         header_len = dn_db->use_long ? 21 : 6;
 800         if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
 801                 goto drop;
 802
 803         /*
 804          * Hop count exceeded.
 805          */
 806         if (++cb->hops > 30)
 807                 goto drop;
 808
 809         skb->dev = rt->dst.dev;
 810
 811         /*
 812          * If packet goes out same interface it came in on, then set
 813          * the Intra-Ethernet bit. This has no effect for short
 814          * packets, so we don't need to test for them here.
 815          */
 816         cb->rt_flags &= ~DN_RT_F_IE;
 817         if (rt->rt_flags & RTCF_DOREDIRECT)
 818                 cb->rt_flags |= DN_RT_F_IE;
 819
 820         return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, skb, dev, skb->dev,
 821                        dn_to_neigh_output);
 822
 823 drop:
 824         kfree_skb(skb);
 825         return NET_RX_DROP;
 826 }
 827
 828 /*
 829  * Used to catch bugs. This should never normally get
 830  * called.
 831  */
 832 static int dn_rt_bug_sk(struct sock *sk, struct sk_buff *skb)
 833 {
 834         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 835
 836         net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
 837                             le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 838
 839         kfree_skb(skb);
 840
 841         return NET_RX_DROP;
 842 }
 843
 844 static int dn_rt_bug(struct sk_buff *skb)
 845 {
 846         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 847
 848         net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
 849                             le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 850
 851         kfree_skb(skb);
 852
 853         return NET_RX_DROP;
 854 }
 855
 856 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
 857 {
 858         return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
 859 }
 860
 861 static unsigned int dn_dst_mtu(const struct dst_entry *dst)
 862 {
 863         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
 864
 865         return mtu ? : dst->dev->mtu;
 866 }
 867
 868 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
 869                                              struct sk_buff *skb,
 870                                              const void *daddr)
 871 {
 872         return __neigh_lookup_errno(&dn_neigh_table, daddr, dst->dev);
 873 }
 874
 875 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 876 {
 877         struct dn_fib_info *fi = res->fi;
 878         struct net_device *dev = rt->dst.dev;
 879         unsigned int mss_metric;
 880         struct neighbour *n;
 881
 882         if (fi) {
 883                 if (DN_FIB_RES_GW(*res) &&
 884                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 885                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 886                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
 887         }
 888         rt->rt_type = res->type;
 889
 890         if (dev != NULL && rt->n == NULL) {
 891                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 892                 if (IS_ERR(n))
 893                         return PTR_ERR(n);
 894                 rt->n = n;
 895         }
 896
 897         if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
 898                 dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
 899         mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
 900         if (mss_metric) {
 901                 unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
 902                 if (mss_metric > mss)
 903                         dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
 904         }
 905         return 0;
 906 }
 907
 908 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 909 {
 910         __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 911         int match = 16;
 912         while(tmp) {
 913                 tmp >>= 1;
 914                 match--;
 915         }
 916         return match;
 917 }
 918
 919 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 920 {
 921         __le16 saddr = 0;
 922         struct dn_dev *dn_db;
 923         struct dn_ifaddr *ifa;
 924         int best_match = 0;
 925         int ret;
 926
 927         rcu_read_lock();
 928         dn_db = rcu_dereference(dev->dn_ptr);
 929         for (ifa = rcu_dereference(dn_db->ifa_list);
 930              ifa != NULL;
 931              ifa = rcu_dereference(ifa->ifa_next)) {
 932                 if (ifa->ifa_scope > scope)
 933                         continue;
 934                 if (!daddr) {
 935                         saddr = ifa->ifa_local;
 936                         break;
 937                 }
 938                 ret = dn_match_addr(daddr, ifa->ifa_local);
 939                 if (ret > best_match)
 940                         saddr = ifa->ifa_local;
 941                 if (best_match == 0)
 942                         saddr = ifa->ifa_local;
 943         }
 944         rcu_read_unlock();
 945
 946         return saddr;
 947 }
 948
 949 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 950 {
 951         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 952 }
 953
 954 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 955 {
 956         __le16 mask = dnet_make_mask(res->prefixlen);
 957         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 958 }
 959
 960 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowidn *oldflp, int try_hard)
 961 {
 962         struct flowidn fld = {
 963                 .daddr = oldflp->daddr,
 964                 .saddr = oldflp->saddr,
 965                 .flowidn_scope = RT_SCOPE_UNIVERSE,
 966                 .flowidn_mark = oldflp->flowidn_mark,
 967                 .flowidn_iif = LOOPBACK_IFINDEX,
 968                 .flowidn_oif = oldflp->flowidn_oif,
 969         };
 970         struct dn_route *rt = NULL;
 971         struct net_device *dev_out = NULL, *dev;
 972         struct neighbour *neigh = NULL;
 973         unsigned int hash;
 974         unsigned int flags = 0;
 975         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 976         int err;
 977         int free_res = 0;
 978         __le16 gateway = 0;
 979
 980         if (decnet_debug_level & 16)
 981                 printk(KERN_DEBUG
 982                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 983                        " iif=%d oif=%d\n", le16_to_cpu(oldflp->daddr),
 984                        le16_to_cpu(oldflp->saddr),
 985                        oldflp->flowidn_mark, LOOPBACK_IFINDEX,
 986                        oldflp->flowidn_oif);
 987
 988         /* If we have an output interface, verify its a DECnet device */
 989         if (oldflp->flowidn_oif) {
 990                 dev_out = dev_get_by_index(&init_net, oldflp->flowidn_oif);
 991                 err = -ENODEV;
 992                 if (dev_out && dev_out->dn_ptr == NULL) {
 993                         dev_put(dev_out);
 994                         dev_out = NULL;
 995                 }
 996                 if (dev_out == NULL)
 997                         goto out;
 998         }
 999
1000         /* If we have a source address, verify that its a local address */
1001         if (oldflp->saddr) {
1002                 err = -EADDRNOTAVAIL;
1003
1004                 if (dev_out) {
1005                         if (dn_dev_islocal(dev_out, oldflp->saddr))
1006                                 goto source_ok;
1007                         dev_put(dev_out);
1008                         goto out;
1009                 }
1010                 rcu_read_lock();
1011                 for_each_netdev_rcu(&init_net, dev) {
1012                         if (!dev->dn_ptr)
1013                                 continue;
1014                         if (!dn_dev_islocal(dev, oldflp->saddr))
1015                                 continue;
1016                         if ((dev->flags & IFF_LOOPBACK) &&
1017                             oldflp->daddr &&
1018                             !dn_dev_islocal(dev, oldflp->daddr))
1019                                 continue;
1020
1021                         dev_out = dev;
1022                         break;
1023                 }
1024                 rcu_read_unlock();
1025                 if (dev_out == NULL)
1026                         goto out;
1027                 dev_hold(dev_out);
1028 source_ok:
1029                 ;
1030         }
1031
1032         /* No destination? Assume its local */
1033         if (!fld.daddr) {
1034                 fld.daddr = fld.saddr;
1035
1036                 err = -EADDRNOTAVAIL;
1037                 if (dev_out)
1038                         dev_put(dev_out);
1039                 dev_out = init_net.loopback_dev;
1040                 dev_hold(dev_out);
1041                 if (!fld.daddr) {
1042                         fld.daddr =
1043                         fld.saddr = dnet_select_source(dev_out, 0,
1044                                                        RT_SCOPE_HOST);
1045                         if (!fld.daddr)
1046                                 goto out;
1047                 }
1048                 fld.flowidn_oif = LOOPBACK_IFINDEX;
1049                 res.type = RTN_LOCAL;
1050                 goto make_route;
1051         }
1052
1053         if (decnet_debug_level & 16)
1054                 printk(KERN_DEBUG
1055                        "dn_route_output_slow: initial checks complete."
1056                        " dst=%04x src=%04x oif=%d try_hard=%d\n",
1057                        le16_to_cpu(fld.daddr), le16_to_cpu(fld.saddr),
1058                        fld.flowidn_oif, try_hard);
1059
1060         /*
1061          * N.B. If the kernel is compiled without router support then
1062          * dn_fib_lookup() will evaluate to non-zero so this if () block
1063          * will always be executed.
1064          */
1065         err = -ESRCH;
1066         if (try_hard || (err = dn_fib_lookup(&fld, &res)) != 0) {
1067                 struct dn_dev *dn_db;
1068                 if (err != -ESRCH)
1069                         goto out;
1070                 /*
1071                  * Here the fallback is basically the standard algorithm for
1072                  * routing in endnodes which is described in the DECnet routing
1073                  * docs
1074                  *
1075                  * If we are not trying hard, look in neighbour cache.
1076                  * The result is tested to ensure that if a specific output
1077                  * device/source address was requested, then we honour that
1078                  * here
1079                  */
1080                 if (!try_hard) {
1081                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fld.daddr);
1082                         if (neigh) {
1083                                 if ((oldflp->flowidn_oif &&
1084                                     (neigh->dev->ifindex != oldflp->flowidn_oif)) ||
1085                                     (oldflp->saddr &&
1086                                     (!dn_dev_islocal(neigh->dev,
1087                                                      oldflp->saddr)))) {
1088                                         neigh_release(neigh);
1089                                         neigh = NULL;
1090                                 } else {
1091                                         if (dev_out)
1092                                                 dev_put(dev_out);
1093                                         if (dn_dev_islocal(neigh->dev, fld.daddr)) {
1094                                                 dev_out = init_net.loopback_dev;
1095                                                 res.type = RTN_LOCAL;
1096                                         } else {
1097                                                 dev_out = neigh->dev;
1098                                         }
1099                                         dev_hold(dev_out);
1100                                         goto select_source;
1101                                 }
1102                         }
1103                 }
1104
1105                 /* Not there? Perhaps its a local address */
1106                 if (dev_out == NULL)
1107                         dev_out = dn_dev_get_default();
1108                 err = -ENODEV;
1109                 if (dev_out == NULL)
1110                         goto out;
1111                 dn_db = rcu_dereference_raw(dev_out->dn_ptr);
1112                 /* Possible improvement - check all devices for local addr */
1113                 if (dn_dev_islocal(dev_out, fld.daddr)) {
1114                         dev_put(dev_out);
1115                         dev_out = init_net.loopback_dev;
1116                         dev_hold(dev_out);
1117                         res.type = RTN_LOCAL;
1118                         goto select_source;
1119                 }
1120                 /* Not local either.... try sending it to the default router */
1121                 neigh = neigh_clone(dn_db->router);
1122                 BUG_ON(neigh && neigh->dev != dev_out);
1123
1124                 /* Ok then, we assume its directly connected and move on */
1125 select_source:
1126                 if (neigh)
1127                         gateway = ((struct dn_neigh *)neigh)->addr;
1128                 if (gateway == 0)
1129                         gateway = fld.daddr;
1130                 if (fld.saddr == 0) {
1131                         fld.saddr = dnet_select_source(dev_out, gateway,
1132                                                        res.type == RTN_LOCAL ?
1133                                                        RT_SCOPE_HOST :
1134                                                        RT_SCOPE_LINK);
1135                         if (fld.saddr == 0 && res.type != RTN_LOCAL)
1136                                 goto e_addr;
1137                 }
1138                 fld.flowidn_oif = dev_out->ifindex;
1139                 goto make_route;
1140         }
1141         free_res = 1;
1142
1143         if (res.type == RTN_NAT)
1144                 goto e_inval;
1145
1146         if (res.type == RTN_LOCAL) {
1147                 if (!fld.saddr)
1148                         fld.saddr = fld.daddr;
1149                 if (dev_out)
1150                         dev_put(dev_out);
1151                 dev_out = init_net.loopback_dev;
1152                 dev_hold(dev_out);
1153                 fld.flowidn_oif = dev_out->ifindex;
1154                 if (res.fi)
1155                         dn_fib_info_put(res.fi);
1156                 res.fi = NULL;
1157                 goto make_route;
1158         }
1159
1160         if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1161                 dn_fib_select_multipath(&fld, &res);
1162
1163         /*
1164          * We could add some logic to deal with default routes here and
1165          * get rid of some of the special casing above.
1166          */
1167
1168         if (!fld.saddr)
1169                 fld.saddr = DN_FIB_RES_PREFSRC(res);
1170
1171         if (dev_out)
1172                 dev_put(dev_out);
1173         dev_out = DN_FIB_RES_DEV(res);
1174         dev_hold(dev_out);
1175         fld.flowidn_oif = dev_out->ifindex;
1176         gateway = DN_FIB_RES_GW(res);
1177
1178 make_route:
1179         if (dev_out->flags & IFF_LOOPBACK)
1180                 flags |= RTCF_LOCAL;
1181
1182         rt = dst_alloc(&dn_dst_ops, dev_out, 1, DST_OBSOLETE_NONE, DST_HOST);
1183         if (rt == NULL)
1184                 goto e_nobufs;
1185
1186         memset(&rt->fld, 0, sizeof(rt->fld));
1187         rt->fld.saddr        = oldflp->saddr;
1188         rt->fld.daddr        = oldflp->daddr;
1189         rt->fld.flowidn_oif  = oldflp->flowidn_oif;
1190         rt->fld.flowidn_iif  = 0;
1191         rt->fld.flowidn_mark = oldflp->flowidn_mark;
1192
1193         rt->rt_saddr      = fld.saddr;
1194         rt->rt_daddr      = fld.daddr;
1195         rt->rt_gateway    = gateway ? gateway : fld.daddr;
1196         rt->rt_local_src  = fld.saddr;
1197
1198         rt->rt_dst_map    = fld.daddr;
1199         rt->rt_src_map    = fld.saddr;
1200
1201         rt->n = neigh;
1202         neigh = NULL;
1203
1204         rt->dst.lastuse = jiffies;
1205         rt->dst.output  = dn_output;
1206         rt->dst.input   = dn_rt_bug;
1207         rt->rt_flags      = flags;
1208         if (flags & RTCF_LOCAL)
1209                 rt->dst.input = dn_nsp_rx;
1210
1211         err = dn_rt_set_next_hop(rt, &res);
1212         if (err)
1213                 goto e_neighbour;
1214
1215         hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1216         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1217
1218 done:
1219         if (neigh)
1220                 neigh_release(neigh);
1221         if (free_res)
1222                 dn_fib_res_put(&res);
1223         if (dev_out)
1224                 dev_put(dev_out);
1225 out:
1226         return err;
1227
1228 e_addr:
1229         err = -EADDRNOTAVAIL;
1230         goto done;
1231 e_inval:
1232         err = -EINVAL;
1233         goto done;
1234 e_nobufs:
1235         err = -ENOBUFS;
1236         goto done;
1237 e_neighbour:
1238         dst_free(&rt->dst);
1239         goto e_nobufs;
1240 }
1241
1242
1243 /*
1244  * N.B. The flags may be moved into the flowi at some future stage.
1245  */
1246 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowidn *flp, int flags)
1247 {
1248         unsigned int hash = dn_hash(flp->saddr, flp->daddr);
1249         struct dn_route *rt = NULL;
1250
1251         if (!(flags & MSG_TRYHARD)) {
1252                 rcu_read_lock_bh();
1253                 for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1254                         rt = rcu_dereference_bh(rt->dst.dn_next)) {
1255                         if ((flp->daddr == rt->fld.daddr) &&
1256                             (flp->saddr == rt->fld.saddr) &&
1257                             (flp->flowidn_mark == rt->fld.flowidn_mark) &&
1258                             dn_is_output_route(rt) &&
1259                             (rt->fld.flowidn_oif == flp->flowidn_oif)) {
1260                                 dst_use(&rt->dst, jiffies);
1261                                 rcu_read_unlock_bh();
1262                                 *pprt = &rt->dst;
1263                                 return 0;
1264                         }
1265                 }
1266                 rcu_read_unlock_bh();
1267         }
1268
1269         return dn_route_output_slow(pprt, flp, flags);
1270 }
1271
1272 static int dn_route_output_key(struct dst_entry **pprt, struct flowidn *flp, int flags)
1273 {
1274         int err;
1275
1276         err = __dn_route_output_key(pprt, flp, flags);
1277         if (err == 0 && flp->flowidn_proto) {
1278                 *pprt = xfrm_lookup(&init_net, *pprt,
1279                                     flowidn_to_flowi(flp), NULL, 0);
1280                 if (IS_ERR(*pprt)) {
1281                         err = PTR_ERR(*pprt);
1282                         *pprt = NULL;
1283                 }
1284         }
1285         return err;
1286 }
1287
1288 int dn_route_output_sock(struct dst_entry __rcu **pprt, struct flowidn *fl, struct sock *sk, int flags)
1289 {
1290         int err;
1291
1292         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1293         if (err == 0 && fl->flowidn_proto) {
1294                 *pprt = xfrm_lookup(&init_net, *pprt,
1295                                     flowidn_to_flowi(fl), sk, 0);
1296                 if (IS_ERR(*pprt)) {
1297                         err = PTR_ERR(*pprt);
1298                         *pprt = NULL;
1299                 }
1300         }
1301         return err;
1302 }
1303
1304 static int dn_route_input_slow(struct sk_buff *skb)
1305 {
1306         struct dn_route *rt = NULL;
1307         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1308         struct net_device *in_dev = skb->dev;
1309         struct net_device *out_dev = NULL;
1310         struct dn_dev *dn_db;
1311         struct neighbour *neigh = NULL;
1312         unsigned int hash;
1313         int flags = 0;
1314         __le16 gateway = 0;
1315         __le16 local_src = 0;
1316         struct flowidn fld = {
1317                 .daddr = cb->dst,
1318                 .saddr = cb->src,
1319                 .flowidn_scope = RT_SCOPE_UNIVERSE,
1320                 .flowidn_mark = skb->mark,
1321                 .flowidn_iif = skb->dev->ifindex,
1322         };
1323         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1324         int err = -EINVAL;
1325         int free_res = 0;
1326
1327         dev_hold(in_dev);
1328
1329         if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
1330                 goto out;
1331
1332         /* Zero source addresses are not allowed */
1333         if (fld.saddr == 0)
1334                 goto out;
1335
1336         /*
1337          * In this case we've just received a packet from a source
1338          * outside ourselves pretending to come from us. We don't
1339          * allow it any further to prevent routing loops, spoofing and
1340          * other nasties. Loopback packets already have the dst attached
1341          * so this only affects packets which have originated elsewhere.
1342          */
1343         err  = -ENOTUNIQ;
1344         if (dn_dev_islocal(in_dev, cb->src))
1345                 goto out;
1346
1347         err = dn_fib_lookup(&fld, &res);
1348         if (err) {
1349                 if (err != -ESRCH)
1350                         goto out;
1351                 /*
1352                  * Is the destination us ?
1353                  */
1354                 if (!dn_dev_islocal(in_dev, cb->dst))
1355                         goto e_inval;
1356
1357                 res.type = RTN_LOCAL;
1358         } else {
1359                 __le16 src_map = fld.saddr;
1360                 free_res = 1;
1361
1362                 out_dev = DN_FIB_RES_DEV(res);
1363                 if (out_dev == NULL) {
1364                         net_crit_ratelimited("Bug in dn_route_input_slow() No output device\n");
1365                         goto e_inval;
1366                 }
1367                 dev_hold(out_dev);
1368
1369                 if (res.r)
1370                         src_map = fld.saddr; /* no NAT support for now */
1371
1372                 gateway = DN_FIB_RES_GW(res);
1373                 if (res.type == RTN_NAT) {
1374                         fld.daddr = dn_fib_rules_map_destination(fld.daddr, &res);
1375                         dn_fib_res_put(&res);
1376                         free_res = 0;
1377                         if (dn_fib_lookup(&fld, &res))
1378                                 goto e_inval;
1379                         free_res = 1;
1380                         if (res.type != RTN_UNICAST)
1381                                 goto e_inval;
1382                         flags |= RTCF_DNAT;
1383                         gateway = fld.daddr;
1384                 }
1385                 fld.saddr = src_map;
1386         }
1387
1388         switch(res.type) {
1389         case RTN_UNICAST:
1390                 /*
1391                  * Forwarding check here, we only check for forwarding
1392                  * being turned off, if you want to only forward intra
1393                  * area, its up to you to set the routing tables up
1394                  * correctly.
1395                  */
1396                 if (dn_db->parms.forwarding == 0)
1397                         goto e_inval;
1398
1399                 if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1400                         dn_fib_select_multipath(&fld, &res);
1401
1402                 /*
1403                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1404                  * flag as a hint to set the intra-ethernet bit when
1405                  * forwarding. If we've got NAT in operation, we don't do
1406                  * this optimisation.
1407                  */
1408                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1409                         flags |= RTCF_DOREDIRECT;
1410
1411                 local_src = DN_FIB_RES_PREFSRC(res);
1412
1413         case RTN_BLACKHOLE:
1414         case RTN_UNREACHABLE:
1415                 break;
1416         case RTN_LOCAL:
1417                 flags |= RTCF_LOCAL;
1418                 fld.saddr = cb->dst;
1419                 fld.daddr = cb->src;
1420
1421                 /* Routing tables gave us a gateway */
1422                 if (gateway)
1423                         goto make_route;
1424
1425                 /* Packet was intra-ethernet, so we know its on-link */
1426                 if (cb->rt_flags & DN_RT_F_IE) {
1427                         gateway = cb->src;
1428                         goto make_route;
1429                 }
1430
1431                 /* Use the default router if there is one */
1432                 neigh = neigh_clone(dn_db->router);
1433                 if (neigh) {
1434                         gateway = ((struct dn_neigh *)neigh)->addr;
1435                         goto make_route;
1436                 }
1437
1438                 /* Close eyes and pray */
1439                 gateway = cb->src;
1440                 goto make_route;
1441         default:
1442                 goto e_inval;
1443         }
1444
1445 make_route:
1446         rt = dst_alloc(&dn_dst_ops, out_dev, 0, DST_OBSOLETE_NONE, DST_HOST);
1447         if (rt == NULL)
1448                 goto e_nobufs;
1449
1450         memset(&rt->fld, 0, sizeof(rt->fld));
1451         rt->rt_saddr      = fld.saddr;
1452         rt->rt_daddr      = fld.daddr;
1453         rt->rt_gateway    = fld.daddr;
1454         if (gateway)
1455                 rt->rt_gateway = gateway;
1456         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1457
1458         rt->rt_dst_map    = fld.daddr;
1459         rt->rt_src_map    = fld.saddr;
1460
1461         rt->fld.saddr        = cb->src;
1462         rt->fld.daddr        = cb->dst;
1463         rt->fld.flowidn_oif  = 0;
1464         rt->fld.flowidn_iif  = in_dev->ifindex;
1465         rt->fld.flowidn_mark = fld.flowidn_mark;
1466
1467         rt->n = neigh;
1468         rt->dst.lastuse = jiffies;
1469         rt->dst.output = dn_rt_bug_sk;
1470         switch (res.type) {
1471         case RTN_UNICAST:
1472                 rt->dst.input = dn_forward;
1473                 break;
1474         case RTN_LOCAL:
1475                 rt->dst.output = dn_output;
1476                 rt->dst.input = dn_nsp_rx;
1477                 rt->dst.dev = in_dev;
1478                 flags |= RTCF_LOCAL;
1479                 break;
1480         default:
1481         case RTN_UNREACHABLE:
1482         case RTN_BLACKHOLE:
1483                 rt->dst.input = dst_discard;
1484         }
1485         rt->rt_flags = flags;
1486
1487         err = dn_rt_set_next_hop(rt, &res);
1488         if (err)
1489                 goto e_neighbour;
1490
1491         hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1492         dn_insert_route(rt, hash, &rt);
1493         skb_dst_set(skb, &rt->dst);
1494
1495 done:
1496         if (neigh)
1497                 neigh_release(neigh);
1498         if (free_res)
1499                 dn_fib_res_put(&res);
1500         dev_put(in_dev);
1501         if (out_dev)
1502                 dev_put(out_dev);
1503 out:
1504         return err;
1505
1506 e_inval:
1507         err = -EINVAL;
1508         goto done;
1509
1510 e_nobufs:
1511         err = -ENOBUFS;
1512         goto done;
1513
1514 e_neighbour:
1515         dst_free(&rt->dst);
1516         goto done;
1517 }
1518
1519 static int dn_route_input(struct sk_buff *skb)
1520 {
1521         struct dn_route *rt;
1522         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1523         unsigned int hash = dn_hash(cb->src, cb->dst);
1524
1525         if (skb_dst(skb))
1526                 return 0;
1527
1528         rcu_read_lock();
1529         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1530             rt = rcu_dereference(rt->dst.dn_next)) {
1531                 if ((rt->fld.saddr == cb->src) &&
1532                     (rt->fld.daddr == cb->dst) &&
1533                     (rt->fld.flowidn_oif == 0) &&
1534                     (rt->fld.flowidn_mark == skb->mark) &&
1535                     (rt->fld.flowidn_iif == cb->iif)) {
1536                         dst_use(&rt->dst, jiffies);
1537                         rcu_read_unlock();
1538                         skb_dst_set(skb, (struct dst_entry *)rt);
1539                         return 0;
1540                 }
1541         }
1542         rcu_read_unlock();
1543
1544         return dn_route_input_slow(skb);
1545 }
1546
1547 static int dn_rt_fill_info(struct sk_buff *skb, u32 portid, u32 seq,
1548                            int event, int nowait, unsigned int flags)
1549 {
1550         struct dn_route *rt = (struct dn_route *)skb_dst(skb);
1551         struct rtmsg *r;
1552         struct nlmsghdr *nlh;
1553         long expires;
1554
1555         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
1556         if (!nlh)
1557                 return -EMSGSIZE;
1558
1559         r = nlmsg_data(nlh);
1560         r->rtm_family = AF_DECnet;
1561         r->rtm_dst_len = 16;
1562         r->rtm_src_len = 0;
1563         r->rtm_tos = 0;
1564         r->rtm_table = RT_TABLE_MAIN;
1565         r->rtm_type = rt->rt_type;
1566         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1567         r->rtm_scope = RT_SCOPE_UNIVERSE;
1568         r->rtm_protocol = RTPROT_UNSPEC;
1569
1570         if (rt->rt_flags & RTCF_NOTIFY)
1571                 r->rtm_flags |= RTM_F_NOTIFY;
1572
1573         if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN) < 0 ||
1574             nla_put_le16(skb, RTA_DST, rt->rt_daddr) < 0)
1575                 goto errout;
1576
1577         if (rt->fld.saddr) {
1578                 r->rtm_src_len = 16;
1579                 if (nla_put_le16(skb, RTA_SRC, rt->fld.saddr) < 0)
1580                         goto errout;
1581         }
1582         if (rt->dst.dev &&
1583             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex) < 0)
1584                 goto errout;
1585
1586         /*
1587          * Note to self - change this if input routes reverse direction when
1588          * they deal only with inputs and not with replies like they do
1589          * currently.
1590          */
1591         if (nla_put_le16(skb, RTA_PREFSRC, rt->rt_local_src) < 0)
1592                 goto errout;
1593
1594         if (rt->rt_daddr != rt->rt_gateway &&
1595             nla_put_le16(skb, RTA_GATEWAY, rt->rt_gateway) < 0)
1596                 goto errout;
1597
1598         if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
1599                 goto errout;
1600
1601         expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
1602         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires,
1603                                rt->dst.error) < 0)
1604                 goto errout;
1605
1606         if (dn_is_input_route(rt) &&
1607             nla_put_u32(skb, RTA_IIF, rt->fld.flowidn_iif) < 0)
1608                 goto errout;
1609
1610         nlmsg_end(skb, nlh);
1611         return 0;
1612
1613 errout:
1614         nlmsg_cancel(skb, nlh);
1615         return -EMSGSIZE;
1616 }
1617
1618 const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
1619         [RTA_DST]               = { .type = NLA_U16 },
1620         [RTA_SRC]               = { .type = NLA_U16 },
1621         [RTA_IIF]               = { .type = NLA_U32 },
1622         [RTA_OIF]               = { .type = NLA_U32 },
1623         [RTA_GATEWAY]           = { .type = NLA_U16 },
1624         [RTA_PRIORITY]          = { .type = NLA_U32 },
1625         [RTA_PREFSRC]           = { .type = NLA_U16 },
1626         [RTA_METRICS]           = { .type = NLA_NESTED },
1627         [RTA_MULTIPATH]         = { .type = NLA_NESTED },
1628         [RTA_TABLE]             = { .type = NLA_U32 },
1629         [RTA_MARK]              = { .type = NLA_U32 },
1630 };
1631
1632 /*
1633  * This is called by both endnodes and routers now.
1634  */
1635 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
1636 {
1637         struct net *net = sock_net(in_skb->sk);
1638         struct rtmsg *rtm = nlmsg_data(nlh);
1639         struct dn_route *rt = NULL;
1640         struct dn_skb_cb *cb;
1641         int err;
1642         struct sk_buff *skb;
1643         struct flowidn fld;
1644         struct nlattr *tb[RTA_MAX+1];
1645
1646         if (!net_eq(net, &init_net))
1647                 return -EINVAL;
1648
1649         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_dn_policy);
1650         if (err < 0)
1651                 return err;
1652
1653         memset(&fld, 0, sizeof(fld));
1654         fld.flowidn_proto = DNPROTO_NSP;
1655
1656         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1657         if (skb == NULL)
1658                 return -ENOBUFS;
1659         skb_reset_mac_header(skb);
1660         cb = DN_SKB_CB(skb);
1661
1662         if (tb[RTA_SRC])
1663                 fld.saddr = nla_get_le16(tb[RTA_SRC]);
1664
1665         if (tb[RTA_DST])
1666                 fld.daddr = nla_get_le16(tb[RTA_DST]);
1667
1668         if (tb[RTA_IIF])
1669                 fld.flowidn_iif = nla_get_u32(tb[RTA_IIF]);
1670
1671         if (fld.flowidn_iif) {
1672                 struct net_device *dev;
1673                 dev = __dev_get_by_index(&init_net, fld.flowidn_iif);
1674                 if (!dev || !dev->dn_ptr) {
1675                         kfree_skb(skb);
1676                         return -ENODEV;
1677                 }
1678                 skb->protocol = htons(ETH_P_DNA_RT);
1679                 skb->dev = dev;
1680                 cb->src = fld.saddr;
1681                 cb->dst = fld.daddr;
1682                 local_bh_disable();
1683                 err = dn_route_input(skb);
1684                 local_bh_enable();
1685                 memset(cb, 0, sizeof(struct dn_skb_cb));
1686                 rt = (struct dn_route *)skb_dst(skb);
1687                 if (!err && -rt->dst.error)
1688                         err = rt->dst.error;
1689         } else {
1690                 if (tb[RTA_OIF])
1691                         fld.flowidn_oif = nla_get_u32(tb[RTA_OIF]);
1692
1693                 err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
1694         }
1695
1696         skb->dev = NULL;
1697         if (err)
1698                 goto out_free;
1699         skb_dst_set(skb, &rt->dst);
1700         if (rtm->rtm_flags & RTM_F_NOTIFY)
1701                 rt->rt_flags |= RTCF_NOTIFY;
1702
1703         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1704         if (err < 0) {
1705                 err = -EMSGSIZE;
1706                 goto out_free;
1707         }
1708
1709         return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).portid);
1710
1711 out_free:
1712         kfree_skb(skb);
1713         return err;
1714 }
1715
1716 /*
1717  * For routers, this is called from dn_fib_dump, but for endnodes its
1718  * called directly from the rtnetlink dispatch table.
1719  */
1720 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1721 {
1722         struct net *net = sock_net(skb->sk);
1723         struct dn_route *rt;
1724         int h, s_h;
1725         int idx, s_idx;
1726         struct rtmsg *rtm;
1727
1728         if (!net_eq(net, &init_net))
1729                 return 0;
1730
1731         if (nlmsg_len(cb->nlh) < sizeof(struct rtmsg))
1732                 return -EINVAL;
1733
1734         rtm = nlmsg_data(cb->nlh);
1735         if (!(rtm->rtm_flags & RTM_F_CLONED))
1736                 return 0;
1737
1738         s_h = cb->args[0];
1739         s_idx = idx = cb->args[1];
1740         for(h = 0; h <= dn_rt_hash_mask; h++) {
1741                 if (h < s_h)
1742                         continue;
1743                 if (h > s_h)
1744                         s_idx = 0;
1745                 rcu_read_lock_bh();
1746                 for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1747                         rt;
1748                         rt = rcu_dereference_bh(rt->dst.dn_next), idx++) {
1749                         if (idx < s_idx)
1750                                 continue;
1751                         skb_dst_set(skb, dst_clone(&rt->dst));
1752                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).portid,
1753                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1754                                         1, NLM_F_MULTI) < 0) {
1755                                 skb_dst_drop(skb);
1756                                 rcu_read_unlock_bh();
1757                                 goto done;
1758                         }
1759                         skb_dst_drop(skb);
1760                 }
1761                 rcu_read_unlock_bh();
1762         }
1763
1764 done:
1765         cb->args[0] = h;
1766         cb->args[1] = idx;
1767         return skb->len;
1768 }
1769
1770 #ifdef CONFIG_PROC_FS
1771 struct dn_rt_cache_iter_state {
1772         int bucket;
1773 };
1774
1775 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1776 {
1777         struct dn_route *rt = NULL;
1778         struct dn_rt_cache_iter_state *s = seq->private;
1779
1780         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1781                 rcu_read_lock_bh();
1782                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1783                 if (rt)
1784                         break;
1785                 rcu_read_unlock_bh();
1786         }
1787         return rt;
1788 }
1789
1790 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1791 {
1792         struct dn_rt_cache_iter_state *s = seq->private;
1793
1794         rt = rcu_dereference_bh(rt->dst.dn_next);
1795         while (!rt) {
1796                 rcu_read_unlock_bh();
1797                 if (--s->bucket < 0)
1798                         break;
1799                 rcu_read_lock_bh();
1800                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1801         }
1802         return rt;
1803 }
1804
1805 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1806 {
1807         struct dn_route *rt = dn_rt_cache_get_first(seq);
1808
1809         if (rt) {
1810                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1811                         --*pos;
1812         }
1813         return *pos ? NULL : rt;
1814 }
1815
1816 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1817 {
1818         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1819         ++*pos;
1820         return rt;
1821 }
1822
1823 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1824 {
1825         if (v)
1826                 rcu_read_unlock_bh();
1827 }
1828
1829 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1830 {
1831         struct dn_route *rt = v;
1832         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1833
1834         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1835                    rt->dst.dev ? rt->dst.dev->name : "*",
1836                    dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1837                    dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1838                    atomic_read(&rt->dst.__refcnt),
1839                    rt->dst.__use, 0);
1840         return 0;
1841 }
1842
1843 static const struct seq_operations dn_rt_cache_seq_ops = {
1844         .start  = dn_rt_cache_seq_start,
1845         .next   = dn_rt_cache_seq_next,
1846         .stop   = dn_rt_cache_seq_stop,
1847         .show   = dn_rt_cache_seq_show,
1848 };
1849
1850 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1851 {
1852         return seq_open_private(file, &dn_rt_cache_seq_ops,
1853                         sizeof(struct dn_rt_cache_iter_state));
1854 }
1855
1856 static const struct file_operations dn_rt_cache_seq_fops = {
1857         .owner   = THIS_MODULE,
1858         .open    = dn_rt_cache_seq_open,
1859         .read    = seq_read,
1860         .llseek  = seq_lseek,
1861         .release = seq_release_private,
1862 };
1863
1864 #endif /* CONFIG_PROC_FS */
1865
1866 void __init dn_route_init(void)
1867 {
1868         int i, goal, order;
1869
1870         dn_dst_ops.kmem_cachep =
1871                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1872                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1873         dst_entries_init(&dn_dst_ops);
1874         setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1875         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1876         add_timer(&dn_route_timer);
1877
1878         goal = totalram_pages >> (26 - PAGE_SHIFT);
1879
1880         for(order = 0; (1UL << order) < goal; order++)
1881                 /* NOTHING */;
1882
1883         /*
1884          * Only want 1024 entries max, since the table is very, very unlikely
1885          * to be larger than that.
1886          */
1887         while(order && ((((1UL << order) * PAGE_SIZE) /
1888                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1889                 order--;
1890
1891         do {
1892                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1893                         sizeof(struct dn_rt_hash_bucket);
1894                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1895                         dn_rt_hash_mask--;
1896                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1897                         __get_free_pages(GFP_ATOMIC, order);
1898         } while (dn_rt_hash_table == NULL && --order > 0);
1899
1900         if (!dn_rt_hash_table)
1901                 panic("Failed to allocate DECnet route cache hash table\n");
1902
1903         printk(KERN_INFO
1904                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1905                 dn_rt_hash_mask,
1906                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1907
1908         dn_rt_hash_mask--;
1909         for(i = 0; i <= dn_rt_hash_mask; i++) {
1910                 spin_lock_init(&dn_rt_hash_table[i].lock);
1911                 dn_rt_hash_table[i].chain = NULL;
1912         }
1913
1914         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1915
1916         proc_create("decnet_cache", S_IRUGO, init_net.proc_net,
1917                     &dn_rt_cache_seq_fops);
1918
1919 #ifdef CONFIG_DECNET_ROUTER
1920         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1921                       dn_fib_dump, NULL);
1922 #else
1923         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1924                       dn_cache_dump, NULL);
1925 #endif
1926 }
1927
1928 void __exit dn_route_cleanup(void)
1929 {
1930         del_timer(&dn_route_timer);
1931         dn_run_flush(0);
1932
1933         remove_proc_entry("decnet_cache", init_net.proc_net);
1934         dst_entries_destroy(&dn_dst_ops);
1935 }
1936