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(struct timer_list *unused);
 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);
 135 int decnet_dst_gc_interval = 2;
 136
 137 static struct dst_ops dn_dst_ops = {
 138         .family =               PF_DECnet,
 139         .gc_thresh =            128,
 140         .gc =                   dn_dst_gc,
 141         .check =                dn_dst_check,
 142         .default_advmss =       dn_dst_default_advmss,
 143         .mtu =                  dn_dst_mtu,
 144         .cow_metrics =          dst_cow_metrics_generic,
 145         .destroy =              dn_dst_destroy,
 146         .ifdown =               dn_dst_ifdown,
 147         .negative_advice =      dn_dst_negative_advice,
 148         .link_failure =         dn_dst_link_failure,
 149         .update_pmtu =          dn_dst_update_pmtu,
 150         .redirect =             dn_dst_redirect,
 151         .neigh_lookup =         dn_dst_neigh_lookup,
 152 };
 153
 154 static void dn_dst_destroy(struct dst_entry *dst)
 155 {
 156         struct dn_route *rt = (struct dn_route *) dst;
 157
 158         if (rt->n)
 159                 neigh_release(rt->n);
 160         dst_destroy_metrics_generic(dst);
 161 }
 162
 163 static void dn_dst_ifdown(struct dst_entry *dst, struct net_device *dev, int how)
 164 {
 165         if (how) {
 166                 struct dn_route *rt = (struct dn_route *) dst;
 167                 struct neighbour *n = rt->n;
 168
 169                 if (n && n->dev == dev) {
 170                         n->dev = dev_net(dev)->loopback_dev;
 171                         dev_hold(n->dev);
 172                         dev_put(dev);
 173                 }
 174         }
 175 }
 176
 177 static __inline__ unsigned int dn_hash(__le16 src, __le16 dst)
 178 {
 179         __u16 tmp = (__u16 __force)(src ^ dst);
 180         tmp ^= (tmp >> 3);
 181         tmp ^= (tmp >> 5);
 182         tmp ^= (tmp >> 10);
 183         return dn_rt_hash_mask & (unsigned int)tmp;
 184 }
 185
 186 static void dn_dst_check_expire(struct timer_list *unused)
 187 {
 188         int i;
 189         struct dn_route *rt;
 190         struct dn_route __rcu **rtp;
 191         unsigned long now = jiffies;
 192         unsigned long expire = 120 * HZ;
 193
 194         for (i = 0; i <= dn_rt_hash_mask; i++) {
 195                 rtp = &dn_rt_hash_table[i].chain;
 196
 197                 spin_lock(&dn_rt_hash_table[i].lock);
 198                 while ((rt = rcu_dereference_protected(*rtp,
 199                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 200                         if (atomic_read(&rt->dst.__refcnt) > 1 ||
 201                             (now - rt->dst.lastuse) < expire) {
 202                                 rtp = &rt->dn_next;
 203                                 continue;
 204                         }
 205                         *rtp = rt->dn_next;
 206                         rt->dn_next = NULL;
 207                         dst_dev_put(&rt->dst);
 208                         dst_release(&rt->dst);
 209                 }
 210                 spin_unlock(&dn_rt_hash_table[i].lock);
 211
 212                 if ((jiffies - now) > 0)
 213                         break;
 214         }
 215
 216         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 217 }
 218
 219 static int dn_dst_gc(struct dst_ops *ops)
 220 {
 221         struct dn_route *rt;
 222         struct dn_route __rcu **rtp;
 223         int i;
 224         unsigned long now = jiffies;
 225         unsigned long expire = 10 * HZ;
 226
 227         for (i = 0; i <= dn_rt_hash_mask; i++) {
 228
 229                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 230                 rtp = &dn_rt_hash_table[i].chain;
 231
 232                 while ((rt = rcu_dereference_protected(*rtp,
 233                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 234                         if (atomic_read(&rt->dst.__refcnt) > 1 ||
 235                             (now - rt->dst.lastuse) < expire) {
 236                                 rtp = &rt->dn_next;
 237                                 continue;
 238                         }
 239                         *rtp = rt->dn_next;
 240                         rt->dn_next = NULL;
 241                         dst_dev_put(&rt->dst);
 242                         dst_release(&rt->dst);
 243                         break;
 244                 }
 245                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 246         }
 247
 248         return 0;
 249 }
 250
 251 /*
 252  * The decnet standards don't impose a particular minimum mtu, what they
 253  * do insist on is that the routing layer accepts a datagram of at least
 254  * 230 bytes long. Here we have to subtract the routing header length from
 255  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 256  * assume the worst and use a long header size.
 257  *
 258  * We update both the mtu and the advertised mss (i.e. the segment size we
 259  * advertise to the other end).
 260  */
 261 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
 262                                struct sk_buff *skb, u32 mtu)
 263 {
 264         struct dn_route *rt = (struct dn_route *) dst;
 265         struct neighbour *n = rt->n;
 266         u32 min_mtu = 230;
 267         struct dn_dev *dn;
 268
 269         dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL;
 270
 271         if (dn && dn->use_long == 0)
 272                 min_mtu -= 6;
 273         else
 274                 min_mtu -= 21;
 275
 276         if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
 277                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
 278                         dst_metric_set(dst, RTAX_MTU, mtu);
 279                         dst_set_expires(dst, dn_rt_mtu_expires);
 280                 }
 281                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 282                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 283                         u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
 284                         if (!existing_mss || existing_mss > mss)
 285                                 dst_metric_set(dst, RTAX_ADVMSS, mss);
 286                 }
 287         }
 288 }
 289
 290 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
 291                             struct sk_buff *skb)
 292 {
 293 }
 294
 295 /*
 296  * When a route has been marked obsolete. (e.g. routing cache flush)
 297  */
 298 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 299 {
 300         return NULL;
 301 }
 302
 303 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 304 {
 305         dst_release(dst);
 306         return NULL;
 307 }
 308
 309 static void dn_dst_link_failure(struct sk_buff *skb)
 310 {
 311 }
 312
 313 static inline int compare_keys(struct flowidn *fl1, struct flowidn *fl2)
 314 {
 315         return ((fl1->daddr ^ fl2->daddr) |
 316                 (fl1->saddr ^ fl2->saddr) |
 317                 (fl1->flowidn_mark ^ fl2->flowidn_mark) |
 318                 (fl1->flowidn_scope ^ fl2->flowidn_scope) |
 319                 (fl1->flowidn_oif ^ fl2->flowidn_oif) |
 320                 (fl1->flowidn_iif ^ fl2->flowidn_iif)) == 0;
 321 }
 322
 323 static int dn_insert_route(struct dn_route *rt, unsigned int hash, struct dn_route **rp)
 324 {
 325         struct dn_route *rth;
 326         struct dn_route __rcu **rthp;
 327         unsigned long now = jiffies;
 328
 329         rthp = &dn_rt_hash_table[hash].chain;
 330
 331         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 332         while ((rth = rcu_dereference_protected(*rthp,
 333                                                 lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
 334                 if (compare_keys(&rth->fld, &rt->fld)) {
 335                         /* Put it first */
 336                         *rthp = rth->dn_next;
 337                         rcu_assign_pointer(rth->dn_next,
 338                                            dn_rt_hash_table[hash].chain);
 339                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 340
 341                         dst_hold_and_use(&rth->dst, now);
 342                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 343
 344                         dst_release_immediate(&rt->dst);
 345                         *rp = rth;
 346                         return 0;
 347                 }
 348                 rthp = &rth->dn_next;
 349         }
 350
 351         rcu_assign_pointer(rt->dn_next, dn_rt_hash_table[hash].chain);
 352         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 353
 354         dst_hold_and_use(&rt->dst, now);
 355         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 356         *rp = rt;
 357         return 0;
 358 }
 359
 360 static void dn_run_flush(struct timer_list *unused)
 361 {
 362         int i;
 363         struct dn_route *rt, *next;
 364
 365         for (i = 0; i < dn_rt_hash_mask; i++) {
 366                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 367
 368                 if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
 369                         goto nothing_to_declare;
 370
 371                 for(; rt; rt = next) {
 372                         next = rcu_dereference_raw(rt->dn_next);
 373                         RCU_INIT_POINTER(rt->dn_next, NULL);
 374                         dst_dev_put(&rt->dst);
 375                         dst_release(&rt->dst);
 376                 }
 377
 378 nothing_to_declare:
 379                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 380         }
 381 }
 382
 383 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 384
 385 void dn_rt_cache_flush(int delay)
 386 {
 387         unsigned long now = jiffies;
 388         int user_mode = !in_interrupt();
 389
 390         if (delay < 0)
 391                 delay = dn_rt_min_delay;
 392
 393         spin_lock_bh(&dn_rt_flush_lock);
 394
 395         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 396                 long tmo = (long)(dn_rt_deadline - now);
 397
 398                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 399                         tmo = 0;
 400
 401                 if (delay > tmo)
 402                         delay = tmo;
 403         }
 404
 405         if (delay <= 0) {
 406                 spin_unlock_bh(&dn_rt_flush_lock);
 407                 dn_run_flush(0);
 408                 return;
 409         }
 410
 411         if (dn_rt_deadline == 0)
 412                 dn_rt_deadline = now + dn_rt_max_delay;
 413
 414         dn_rt_flush_timer.expires = now + delay;
 415         add_timer(&dn_rt_flush_timer);
 416         spin_unlock_bh(&dn_rt_flush_lock);
 417 }
 418
 419 /**
 420  * dn_return_short - Return a short packet to its sender
 421  * @skb: The packet to return
 422  *
 423  */
 424 static int dn_return_short(struct sk_buff *skb)
 425 {
 426         struct dn_skb_cb *cb;
 427         unsigned char *ptr;
 428         __le16 *src;
 429         __le16 *dst;
 430
 431         /* Add back headers */
 432         skb_push(skb, skb->data - skb_network_header(skb));
 433
 434         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 435                 return NET_RX_DROP;
 436
 437         cb = DN_SKB_CB(skb);
 438         /* Skip packet length and point to flags */
 439         ptr = skb->data + 2;
 440         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 441
 442         dst = (__le16 *)ptr;
 443         ptr += 2;
 444         src = (__le16 *)ptr;
 445         ptr += 2;
 446         *ptr = 0; /* Zero hop count */
 447
 448         swap(*src, *dst);
 449
 450         skb->pkt_type = PACKET_OUTGOING;
 451         dn_rt_finish_output(skb, NULL, NULL);
 452         return NET_RX_SUCCESS;
 453 }
 454
 455 /**
 456  * dn_return_long - Return a long packet to its sender
 457  * @skb: The long format packet to return
 458  *
 459  */
 460 static int dn_return_long(struct sk_buff *skb)
 461 {
 462         struct dn_skb_cb *cb;
 463         unsigned char *ptr;
 464         unsigned char *src_addr, *dst_addr;
 465         unsigned char tmp[ETH_ALEN];
 466
 467         /* Add back all headers */
 468         skb_push(skb, skb->data - skb_network_header(skb));
 469
 470         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 471                 return NET_RX_DROP;
 472
 473         cb = DN_SKB_CB(skb);
 474         /* Ignore packet length and point to flags */
 475         ptr = skb->data + 2;
 476
 477         /* Skip padding */
 478         if (*ptr & DN_RT_F_PF) {
 479                 char padlen = (*ptr & ~DN_RT_F_PF);
 480                 ptr += padlen;
 481         }
 482
 483         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 484         ptr += 2;
 485         dst_addr = ptr;
 486         ptr += 8;
 487         src_addr = ptr;
 488         ptr += 6;
 489         *ptr = 0; /* Zero hop count */
 490
 491         /* Swap source and destination */
 492         memcpy(tmp, src_addr, ETH_ALEN);
 493         memcpy(src_addr, dst_addr, ETH_ALEN);
 494         memcpy(dst_addr, tmp, ETH_ALEN);
 495
 496         skb->pkt_type = PACKET_OUTGOING;
 497         dn_rt_finish_output(skb, dst_addr, src_addr);
 498         return NET_RX_SUCCESS;
 499 }
 500
 501 /**
 502  * dn_route_rx_packet - Try and find a route for an incoming packet
 503  * @skb: The packet to find a route for
 504  *
 505  * Returns: result of input function if route is found, error code otherwise
 506  */
 507 static int dn_route_rx_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
 508 {
 509         struct dn_skb_cb *cb;
 510         int err;
 511
 512         if ((err = dn_route_input(skb)) == 0)
 513                 return dst_input(skb);
 514
 515         cb = DN_SKB_CB(skb);
 516         if (decnet_debug_level & 4) {
 517                 char *devname = skb->dev ? skb->dev->name : "???";
 518
 519                 printk(KERN_DEBUG
 520                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 521                         (int)cb->rt_flags, devname, skb->len,
 522                         le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
 523                         err, skb->pkt_type);
 524         }
 525
 526         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 527                 switch (cb->rt_flags & DN_RT_PKT_MSK) {
 528                 case DN_RT_PKT_SHORT:
 529                         return dn_return_short(skb);
 530                 case DN_RT_PKT_LONG:
 531                         return dn_return_long(skb);
 532                 }
 533         }
 534
 535         kfree_skb(skb);
 536         return NET_RX_DROP;
 537 }
 538
 539 static int dn_route_rx_long(struct sk_buff *skb)
 540 {
 541         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 542         unsigned char *ptr = skb->data;
 543
 544         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 545                 goto drop_it;
 546
 547         skb_pull(skb, 20);
 548         skb_reset_transport_header(skb);
 549
 550         /* Destination info */
 551         ptr += 2;
 552         cb->dst = dn_eth2dn(ptr);
 553         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 554                 goto drop_it;
 555         ptr += 6;
 556
 557
 558         /* Source info */
 559         ptr += 2;
 560         cb->src = dn_eth2dn(ptr);
 561         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 562                 goto drop_it;
 563         ptr += 6;
 564         /* Other junk */
 565         ptr++;
 566         cb->hops = *ptr++; /* Visit Count */
 567
 568         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
 569                        &init_net, NULL, skb, skb->dev, NULL,
 570                        dn_route_rx_packet);
 571
 572 drop_it:
 573         kfree_skb(skb);
 574         return NET_RX_DROP;
 575 }
 576
 577
 578
 579 static int dn_route_rx_short(struct sk_buff *skb)
 580 {
 581         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 582         unsigned char *ptr = skb->data;
 583
 584         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 585                 goto drop_it;
 586
 587         skb_pull(skb, 5);
 588         skb_reset_transport_header(skb);
 589
 590         cb->dst = *(__le16 *)ptr;
 591         ptr += 2;
 592         cb->src = *(__le16 *)ptr;
 593         ptr += 2;
 594         cb->hops = *ptr & 0x3f;
 595
 596         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
 597                        &init_net, NULL, skb, skb->dev, NULL,
 598                        dn_route_rx_packet);
 599
 600 drop_it:
 601         kfree_skb(skb);
 602         return NET_RX_DROP;
 603 }
 604
 605 static int dn_route_discard(struct net *net, struct sock *sk, struct sk_buff *skb)
 606 {
 607         /*
 608          * I know we drop the packet here, but thats considered success in
 609          * this case
 610          */
 611         kfree_skb(skb);
 612         return NET_RX_SUCCESS;
 613 }
 614
 615 static int dn_route_ptp_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
 616 {
 617         dn_dev_hello(skb);
 618         dn_neigh_pointopoint_hello(skb);
 619         return NET_RX_SUCCESS;
 620 }
 621
 622 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 623 {
 624         struct dn_skb_cb *cb;
 625         unsigned char flags = 0;
 626         __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 627         struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
 628         unsigned char padlen = 0;
 629
 630         if (!net_eq(dev_net(dev), &init_net))
 631                 goto dump_it;
 632
 633         if (dn == NULL)
 634                 goto dump_it;
 635
 636         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 637                 goto out;
 638
 639         if (!pskb_may_pull(skb, 3))
 640                 goto dump_it;
 641
 642         skb_pull(skb, 2);
 643
 644         if (len > skb->len)
 645                 goto dump_it;
 646
 647         skb_trim(skb, len);
 648
 649         flags = *skb->data;
 650
 651         cb = DN_SKB_CB(skb);
 652         cb->stamp = jiffies;
 653         cb->iif = dev->ifindex;
 654
 655         /*
 656          * If we have padding, remove it.
 657          */
 658         if (flags & DN_RT_F_PF) {
 659                 padlen = flags & ~DN_RT_F_PF;
 660                 if (!pskb_may_pull(skb, padlen + 1))
 661                         goto dump_it;
 662                 skb_pull(skb, padlen);
 663                 flags = *skb->data;
 664         }
 665
 666         skb_reset_network_header(skb);
 667
 668         /*
 669          * Weed out future version DECnet
 670          */
 671         if (flags & DN_RT_F_VER)
 672                 goto dump_it;
 673
 674         cb->rt_flags = flags;
 675
 676         if (decnet_debug_level & 1)
 677                 printk(KERN_DEBUG
 678                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 679                         (int)flags, (dev) ? dev->name : "???", len, skb->len,
 680                         padlen);
 681
 682         if (flags & DN_RT_PKT_CNTL) {
 683                 if (unlikely(skb_linearize(skb)))
 684                         goto dump_it;
 685
 686                 switch (flags & DN_RT_CNTL_MSK) {
 687                 case DN_RT_PKT_INIT:
 688                         dn_dev_init_pkt(skb);
 689                         break;
 690                 case DN_RT_PKT_VERI:
 691                         dn_dev_veri_pkt(skb);
 692                         break;
 693                 }
 694
 695                 if (dn->parms.state != DN_DEV_S_RU)
 696                         goto dump_it;
 697
 698                 switch (flags & DN_RT_CNTL_MSK) {
 699                 case DN_RT_PKT_HELO:
 700                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 701                                        &init_net, NULL, skb, skb->dev, NULL,
 702                                        dn_route_ptp_hello);
 703
 704                 case DN_RT_PKT_L1RT:
 705                 case DN_RT_PKT_L2RT:
 706                         return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
 707                                        &init_net, NULL, skb, skb->dev, NULL,
 708                                        dn_route_discard);
 709                 case DN_RT_PKT_ERTH:
 710                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 711                                        &init_net, NULL, skb, skb->dev, NULL,
 712                                        dn_neigh_router_hello);
 713
 714                 case DN_RT_PKT_EEDH:
 715                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 716                                        &init_net, NULL, skb, skb->dev, NULL,
 717                                        dn_neigh_endnode_hello);
 718                 }
 719         } else {
 720                 if (dn->parms.state != DN_DEV_S_RU)
 721                         goto dump_it;
 722
 723                 skb_pull(skb, 1); /* Pull flags */
 724
 725                 switch (flags & DN_RT_PKT_MSK) {
 726                 case DN_RT_PKT_LONG:
 727                         return dn_route_rx_long(skb);
 728                 case DN_RT_PKT_SHORT:
 729                         return dn_route_rx_short(skb);
 730                 }
 731         }
 732
 733 dump_it:
 734         kfree_skb(skb);
 735 out:
 736         return NET_RX_DROP;
 737 }
 738
 739 static int dn_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 740 {
 741         struct dst_entry *dst = skb_dst(skb);
 742         struct dn_route *rt = (struct dn_route *)dst;
 743         struct net_device *dev = dst->dev;
 744         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 745
 746         int err = -EINVAL;
 747
 748         if (rt->n == NULL)
 749                 goto error;
 750
 751         skb->dev = dev;
 752
 753         cb->src = rt->rt_saddr;
 754         cb->dst = rt->rt_daddr;
 755
 756         /*
 757          * Always set the Intra-Ethernet bit on all outgoing packets
 758          * originated on this node. Only valid flag from upper layers
 759          * is return-to-sender-requested. Set hop count to 0 too.
 760          */
 761         cb->rt_flags &= ~DN_RT_F_RQR;
 762         cb->rt_flags |= DN_RT_F_IE;
 763         cb->hops = 0;
 764
 765         return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT,
 766                        &init_net, sk, skb, NULL, dev,
 767                        dn_to_neigh_output);
 768
 769 error:
 770         net_dbg_ratelimited("dn_output: This should not happen\n");
 771
 772         kfree_skb(skb);
 773
 774         return err;
 775 }
 776
 777 static int dn_forward(struct sk_buff *skb)
 778 {
 779         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 780         struct dst_entry *dst = skb_dst(skb);
 781         struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
 782         struct dn_route *rt;
 783         int header_len;
 784         struct net_device *dev = skb->dev;
 785
 786         if (skb->pkt_type != PACKET_HOST)
 787                 goto drop;
 788
 789         /* Ensure that we have enough space for headers */
 790         rt = (struct dn_route *)skb_dst(skb);
 791         header_len = dn_db->use_long ? 21 : 6;
 792         if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
 793                 goto drop;
 794
 795         /*
 796          * Hop count exceeded.
 797          */
 798         if (++cb->hops > 30)
 799                 goto drop;
 800
 801         skb->dev = rt->dst.dev;
 802
 803         /*
 804          * If packet goes out same interface it came in on, then set
 805          * the Intra-Ethernet bit. This has no effect for short
 806          * packets, so we don't need to test for them here.
 807          */
 808         cb->rt_flags &= ~DN_RT_F_IE;
 809         if (rt->rt_flags & RTCF_DOREDIRECT)
 810                 cb->rt_flags |= DN_RT_F_IE;
 811
 812         return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD,
 813                        &init_net, NULL, skb, dev, skb->dev,
 814                        dn_to_neigh_output);
 815
 816 drop:
 817         kfree_skb(skb);
 818         return NET_RX_DROP;
 819 }
 820
 821 /*
 822  * Used to catch bugs. This should never normally get
 823  * called.
 824  */
 825 static int dn_rt_bug_out(struct net *net, struct sock *sk, struct sk_buff *skb)
 826 {
 827         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 828
 829         net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
 830                             le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 831
 832         kfree_skb(skb);
 833
 834         return NET_RX_DROP;
 835 }
 836
 837 static int dn_rt_bug(struct sk_buff *skb)
 838 {
 839         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 840
 841         net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
 842                             le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 843
 844         kfree_skb(skb);
 845
 846         return NET_RX_DROP;
 847 }
 848
 849 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
 850 {
 851         return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
 852 }
 853
 854 static unsigned int dn_dst_mtu(const struct dst_entry *dst)
 855 {
 856         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
 857
 858         return mtu ? : dst->dev->mtu;
 859 }
 860
 861 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
 862                                              struct sk_buff *skb,
 863                                              const void *daddr)
 864 {
 865         return __neigh_lookup_errno(&dn_neigh_table, daddr, dst->dev);
 866 }
 867
 868 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 869 {
 870         struct dn_fib_info *fi = res->fi;
 871         struct net_device *dev = rt->dst.dev;
 872         unsigned int mss_metric;
 873         struct neighbour *n;
 874
 875         if (fi) {
 876                 if (DN_FIB_RES_GW(*res) &&
 877                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 878                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 879                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
 880         }
 881         rt->rt_type = res->type;
 882
 883         if (dev != NULL && rt->n == NULL) {
 884                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 885                 if (IS_ERR(n))
 886                         return PTR_ERR(n);
 887                 rt->n = n;
 888         }
 889
 890         if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
 891                 dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
 892         mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
 893         if (mss_metric) {
 894                 unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
 895                 if (mss_metric > mss)
 896                         dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
 897         }
 898         return 0;
 899 }
 900
 901 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 902 {
 903         __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 904         int match = 16;
 905         while(tmp) {
 906                 tmp >>= 1;
 907                 match--;
 908         }
 909         return match;
 910 }
 911
 912 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 913 {
 914         __le16 saddr = 0;
 915         struct dn_dev *dn_db;
 916         struct dn_ifaddr *ifa;
 917         int best_match = 0;
 918         int ret;
 919
 920         rcu_read_lock();
 921         dn_db = rcu_dereference(dev->dn_ptr);
 922         for (ifa = rcu_dereference(dn_db->ifa_list);
 923              ifa != NULL;
 924              ifa = rcu_dereference(ifa->ifa_next)) {
 925                 if (ifa->ifa_scope > scope)
 926                         continue;
 927                 if (!daddr) {
 928                         saddr = ifa->ifa_local;
 929                         break;
 930                 }
 931                 ret = dn_match_addr(daddr, ifa->ifa_local);
 932                 if (ret > best_match)
 933                         saddr = ifa->ifa_local;
 934                 if (best_match == 0)
 935                         saddr = ifa->ifa_local;
 936         }
 937         rcu_read_unlock();
 938
 939         return saddr;
 940 }
 941
 942 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 943 {
 944         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 945 }
 946
 947 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 948 {
 949         __le16 mask = dnet_make_mask(res->prefixlen);
 950         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 951 }
 952
 953 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowidn *oldflp, int try_hard)
 954 {
 955         struct flowidn fld = {
 956                 .daddr = oldflp->daddr,
 957                 .saddr = oldflp->saddr,
 958                 .flowidn_scope = RT_SCOPE_UNIVERSE,
 959                 .flowidn_mark = oldflp->flowidn_mark,
 960                 .flowidn_iif = LOOPBACK_IFINDEX,
 961                 .flowidn_oif = oldflp->flowidn_oif,
 962         };
 963         struct dn_route *rt = NULL;
 964         struct net_device *dev_out = NULL, *dev;
 965         struct neighbour *neigh = NULL;
 966         unsigned int hash;
 967         unsigned int flags = 0;
 968         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 969         int err;
 970         int free_res = 0;
 971         __le16 gateway = 0;
 972
 973         if (decnet_debug_level & 16)
 974                 printk(KERN_DEBUG
 975                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 976                        " iif=%d oif=%d\n", le16_to_cpu(oldflp->daddr),
 977                        le16_to_cpu(oldflp->saddr),
 978                        oldflp->flowidn_mark, LOOPBACK_IFINDEX,
 979                        oldflp->flowidn_oif);
 980
 981         /* If we have an output interface, verify its a DECnet device */
 982         if (oldflp->flowidn_oif) {
 983                 dev_out = dev_get_by_index(&init_net, oldflp->flowidn_oif);
 984                 err = -ENODEV;
 985                 if (dev_out && dev_out->dn_ptr == NULL) {
 986                         dev_put(dev_out);
 987                         dev_out = NULL;
 988                 }
 989                 if (dev_out == NULL)
 990                         goto out;
 991         }
 992
 993         /* If we have a source address, verify that its a local address */
 994         if (oldflp->saddr) {
 995                 err = -EADDRNOTAVAIL;
 996
 997                 if (dev_out) {
 998                         if (dn_dev_islocal(dev_out, oldflp->saddr))
 999                                 goto source_ok;
1000                         dev_put(dev_out);
1001                         goto out;
1002                 }
1003                 rcu_read_lock();
1004                 for_each_netdev_rcu(&init_net, dev) {
1005                         if (!dev->dn_ptr)
1006                                 continue;
1007                         if (!dn_dev_islocal(dev, oldflp->saddr))
1008                                 continue;
1009                         if ((dev->flags & IFF_LOOPBACK) &&
1010                             oldflp->daddr &&
1011                             !dn_dev_islocal(dev, oldflp->daddr))
1012                                 continue;
1013
1014                         dev_out = dev;
1015                         break;
1016                 }
1017                 rcu_read_unlock();
1018                 if (dev_out == NULL)
1019                         goto out;
1020                 dev_hold(dev_out);
1021 source_ok:
1022                 ;
1023         }
1024
1025         /* No destination? Assume its local */
1026         if (!fld.daddr) {
1027                 fld.daddr = fld.saddr;
1028
1029                 if (dev_out)
1030                         dev_put(dev_out);
1031                 err = -EINVAL;
1032                 dev_out = init_net.loopback_dev;
1033                 if (!dev_out->dn_ptr)
1034                         goto out;
1035                 err = -EADDRNOTAVAIL;
1036                 dev_hold(dev_out);
1037                 if (!fld.daddr) {
1038                         fld.daddr =
1039                         fld.saddr = dnet_select_source(dev_out, 0,
1040                                                        RT_SCOPE_HOST);
1041                         if (!fld.daddr)
1042                                 goto out;
1043                 }
1044                 fld.flowidn_oif = LOOPBACK_IFINDEX;
1045                 res.type = RTN_LOCAL;
1046                 goto make_route;
1047         }
1048
1049         if (decnet_debug_level & 16)
1050                 printk(KERN_DEBUG
1051                        "dn_route_output_slow: initial checks complete."
1052                        " dst=%04x src=%04x oif=%d try_hard=%d\n",
1053                        le16_to_cpu(fld.daddr), le16_to_cpu(fld.saddr),
1054                        fld.flowidn_oif, try_hard);
1055
1056         /*
1057          * N.B. If the kernel is compiled without router support then
1058          * dn_fib_lookup() will evaluate to non-zero so this if () block
1059          * will always be executed.
1060          */
1061         err = -ESRCH;
1062         if (try_hard || (err = dn_fib_lookup(&fld, &res)) != 0) {
1063                 struct dn_dev *dn_db;
1064                 if (err != -ESRCH)
1065                         goto out;
1066                 /*
1067                  * Here the fallback is basically the standard algorithm for
1068                  * routing in endnodes which is described in the DECnet routing
1069                  * docs
1070                  *
1071                  * If we are not trying hard, look in neighbour cache.
1072                  * The result is tested to ensure that if a specific output
1073                  * device/source address was requested, then we honour that
1074                  * here
1075                  */
1076                 if (!try_hard) {
1077                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fld.daddr);
1078                         if (neigh) {
1079                                 if ((oldflp->flowidn_oif &&
1080                                     (neigh->dev->ifindex != oldflp->flowidn_oif)) ||
1081                                     (oldflp->saddr &&
1082                                     (!dn_dev_islocal(neigh->dev,
1083                                                      oldflp->saddr)))) {
1084                                         neigh_release(neigh);
1085                                         neigh = NULL;
1086                                 } else {
1087                                         if (dev_out)
1088                                                 dev_put(dev_out);
1089                                         if (dn_dev_islocal(neigh->dev, fld.daddr)) {
1090                                                 dev_out = init_net.loopback_dev;
1091                                                 res.type = RTN_LOCAL;
1092                                         } else {
1093                                                 dev_out = neigh->dev;
1094                                         }
1095                                         dev_hold(dev_out);
1096                                         goto select_source;
1097                                 }
1098                         }
1099                 }
1100
1101                 /* Not there? Perhaps its a local address */
1102                 if (dev_out == NULL)
1103                         dev_out = dn_dev_get_default();
1104                 err = -ENODEV;
1105                 if (dev_out == NULL)
1106                         goto out;
1107                 dn_db = rcu_dereference_raw(dev_out->dn_ptr);
1108                 if (!dn_db)
1109                         goto e_inval;
1110                 /* Possible improvement - check all devices for local addr */
1111                 if (dn_dev_islocal(dev_out, fld.daddr)) {
1112                         dev_put(dev_out);
1113                         dev_out = init_net.loopback_dev;
1114                         dev_hold(dev_out);
1115                         res.type = RTN_LOCAL;
1116                         goto select_source;
1117                 }
1118                 /* Not local either.... try sending it to the default router */
1119                 neigh = neigh_clone(dn_db->router);
1120                 BUG_ON(neigh && neigh->dev != dev_out);
1121
1122                 /* Ok then, we assume its directly connected and move on */
1123 select_source:
1124                 if (neigh)
1125                         gateway = ((struct dn_neigh *)neigh)->addr;
1126                 if (gateway == 0)
1127                         gateway = fld.daddr;
1128                 if (fld.saddr == 0) {
1129                         fld.saddr = dnet_select_source(dev_out, gateway,
1130                                                        res.type == RTN_LOCAL ?
1131                                                        RT_SCOPE_HOST :
1132                                                        RT_SCOPE_LINK);
1133                         if (fld.saddr == 0 && res.type != RTN_LOCAL)
1134                                 goto e_addr;
1135                 }
1136                 fld.flowidn_oif = dev_out->ifindex;
1137                 goto make_route;
1138         }
1139         free_res = 1;
1140
1141         if (res.type == RTN_NAT)
1142                 goto e_inval;
1143
1144         if (res.type == RTN_LOCAL) {
1145                 if (!fld.saddr)
1146                         fld.saddr = fld.daddr;
1147                 if (dev_out)
1148                         dev_put(dev_out);
1149                 dev_out = init_net.loopback_dev;
1150                 dev_hold(dev_out);
1151                 if (!dev_out->dn_ptr)
1152                         goto e_inval;
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, 0, DST_OBSOLETE_NONE, DST_HOST);
1183         if (rt == NULL)
1184                 goto e_nobufs;
1185
1186         rt->dn_next = NULL;
1187         memset(&rt->fld, 0, sizeof(rt->fld));
1188         rt->fld.saddr        = oldflp->saddr;
1189         rt->fld.daddr        = oldflp->daddr;
1190         rt->fld.flowidn_oif  = oldflp->flowidn_oif;
1191         rt->fld.flowidn_iif  = 0;
1192         rt->fld.flowidn_mark = oldflp->flowidn_mark;
1193
1194         rt->rt_saddr      = fld.saddr;
1195         rt->rt_daddr      = fld.daddr;
1196         rt->rt_gateway    = gateway ? gateway : fld.daddr;
1197         rt->rt_local_src  = fld.saddr;
1198
1199         rt->rt_dst_map    = fld.daddr;
1200         rt->rt_src_map    = fld.saddr;
1201
1202         rt->n = neigh;
1203         neigh = NULL;
1204
1205         rt->dst.lastuse = jiffies;
1206         rt->dst.output  = dn_output;
1207         rt->dst.input   = dn_rt_bug;
1208         rt->rt_flags      = flags;
1209         if (flags & RTCF_LOCAL)
1210                 rt->dst.input = dn_nsp_rx;
1211
1212         err = dn_rt_set_next_hop(rt, &res);
1213         if (err)
1214                 goto e_neighbour;
1215
1216         hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1217         /* dn_insert_route() increments dst->__refcnt */
1218         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1219
1220 done:
1221         if (neigh)
1222                 neigh_release(neigh);
1223         if (free_res)
1224                 dn_fib_res_put(&res);
1225         if (dev_out)
1226                 dev_put(dev_out);
1227 out:
1228         return err;
1229
1230 e_addr:
1231         err = -EADDRNOTAVAIL;
1232         goto done;
1233 e_inval:
1234         err = -EINVAL;
1235         goto done;
1236 e_nobufs:
1237         err = -ENOBUFS;
1238         goto done;
1239 e_neighbour:
1240         dst_release_immediate(&rt->dst);
1241         goto e_nobufs;
1242 }
1243
1244
1245 /*
1246  * N.B. The flags may be moved into the flowi at some future stage.
1247  */
1248 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowidn *flp, int flags)
1249 {
1250         unsigned int hash = dn_hash(flp->saddr, flp->daddr);
1251         struct dn_route *rt = NULL;
1252
1253         if (!(flags & MSG_TRYHARD)) {
1254                 rcu_read_lock_bh();
1255                 for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1256                         rt = rcu_dereference_bh(rt->dn_next)) {
1257                         if ((flp->daddr == rt->fld.daddr) &&
1258                             (flp->saddr == rt->fld.saddr) &&
1259                             (flp->flowidn_mark == rt->fld.flowidn_mark) &&
1260                             dn_is_output_route(rt) &&
1261                             (rt->fld.flowidn_oif == flp->flowidn_oif)) {
1262                                 dst_hold_and_use(&rt->dst, jiffies);
1263                                 rcu_read_unlock_bh();
1264                                 *pprt = &rt->dst;
1265                                 return 0;
1266                         }
1267                 }
1268                 rcu_read_unlock_bh();
1269         }
1270
1271         return dn_route_output_slow(pprt, flp, flags);
1272 }
1273
1274 static int dn_route_output_key(struct dst_entry **pprt, struct flowidn *flp, int flags)
1275 {
1276         int err;
1277
1278         err = __dn_route_output_key(pprt, flp, flags);
1279         if (err == 0 && flp->flowidn_proto) {
1280                 *pprt = xfrm_lookup(&init_net, *pprt,
1281                                     flowidn_to_flowi(flp), NULL, 0);
1282                 if (IS_ERR(*pprt)) {
1283                         err = PTR_ERR(*pprt);
1284                         *pprt = NULL;
1285                 }
1286         }
1287         return err;
1288 }
1289
1290 int dn_route_output_sock(struct dst_entry __rcu **pprt, struct flowidn *fl, struct sock *sk, int flags)
1291 {
1292         int err;
1293
1294         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1295         if (err == 0 && fl->flowidn_proto) {
1296                 *pprt = xfrm_lookup(&init_net, *pprt,
1297                                     flowidn_to_flowi(fl), sk, 0);
1298                 if (IS_ERR(*pprt)) {
1299                         err = PTR_ERR(*pprt);
1300                         *pprt = NULL;
1301                 }
1302         }
1303         return err;
1304 }
1305
1306 static int dn_route_input_slow(struct sk_buff *skb)
1307 {
1308         struct dn_route *rt = NULL;
1309         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1310         struct net_device *in_dev = skb->dev;
1311         struct net_device *out_dev = NULL;
1312         struct dn_dev *dn_db;
1313         struct neighbour *neigh = NULL;
1314         unsigned int hash;
1315         int flags = 0;
1316         __le16 gateway = 0;
1317         __le16 local_src = 0;
1318         struct flowidn fld = {
1319                 .daddr = cb->dst,
1320                 .saddr = cb->src,
1321                 .flowidn_scope = RT_SCOPE_UNIVERSE,
1322                 .flowidn_mark = skb->mark,
1323                 .flowidn_iif = skb->dev->ifindex,
1324         };
1325         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1326         int err = -EINVAL;
1327         int free_res = 0;
1328
1329         dev_hold(in_dev);
1330
1331         if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
1332                 goto out;
1333
1334         /* Zero source addresses are not allowed */
1335         if (fld.saddr == 0)
1336                 goto out;
1337
1338         /*
1339          * In this case we've just received a packet from a source
1340          * outside ourselves pretending to come from us. We don't
1341          * allow it any further to prevent routing loops, spoofing and
1342          * other nasties. Loopback packets already have the dst attached
1343          * so this only affects packets which have originated elsewhere.
1344          */
1345         err  = -ENOTUNIQ;
1346         if (dn_dev_islocal(in_dev, cb->src))
1347                 goto out;
1348
1349         err = dn_fib_lookup(&fld, &res);
1350         if (err) {
1351                 if (err != -ESRCH)
1352                         goto out;
1353                 /*
1354                  * Is the destination us ?
1355                  */
1356                 if (!dn_dev_islocal(in_dev, cb->dst))
1357                         goto e_inval;
1358
1359                 res.type = RTN_LOCAL;
1360         } else {
1361                 __le16 src_map = fld.saddr;
1362                 free_res = 1;
1363
1364                 out_dev = DN_FIB_RES_DEV(res);
1365                 if (out_dev == NULL) {
1366                         net_crit_ratelimited("Bug in dn_route_input_slow() No output device\n");
1367                         goto e_inval;
1368                 }
1369                 dev_hold(out_dev);
1370
1371                 if (res.r)
1372                         src_map = fld.saddr; /* no NAT support for now */
1373
1374                 gateway = DN_FIB_RES_GW(res);
1375                 if (res.type == RTN_NAT) {
1376                         fld.daddr = dn_fib_rules_map_destination(fld.daddr, &res);
1377                         dn_fib_res_put(&res);
1378                         free_res = 0;
1379                         if (dn_fib_lookup(&fld, &res))
1380                                 goto e_inval;
1381                         free_res = 1;
1382                         if (res.type != RTN_UNICAST)
1383                                 goto e_inval;
1384                         flags |= RTCF_DNAT;
1385                         gateway = fld.daddr;
1386                 }
1387                 fld.saddr = src_map;
1388         }
1389
1390         switch(res.type) {
1391         case RTN_UNICAST:
1392                 /*
1393                  * Forwarding check here, we only check for forwarding
1394                  * being turned off, if you want to only forward intra
1395                  * area, its up to you to set the routing tables up
1396                  * correctly.
1397                  */
1398                 if (dn_db->parms.forwarding == 0)
1399                         goto e_inval;
1400
1401                 if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1402                         dn_fib_select_multipath(&fld, &res);
1403
1404                 /*
1405                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1406                  * flag as a hint to set the intra-ethernet bit when
1407                  * forwarding. If we've got NAT in operation, we don't do
1408                  * this optimisation.
1409                  */
1410                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1411                         flags |= RTCF_DOREDIRECT;
1412
1413                 local_src = DN_FIB_RES_PREFSRC(res);
1414
1415         case RTN_BLACKHOLE:
1416         case RTN_UNREACHABLE:
1417                 break;
1418         case RTN_LOCAL:
1419                 flags |= RTCF_LOCAL;
1420                 fld.saddr = cb->dst;
1421                 fld.daddr = cb->src;
1422
1423                 /* Routing tables gave us a gateway */
1424                 if (gateway)
1425                         goto make_route;
1426
1427                 /* Packet was intra-ethernet, so we know its on-link */
1428                 if (cb->rt_flags & DN_RT_F_IE) {
1429                         gateway = cb->src;
1430                         goto make_route;
1431                 }
1432
1433                 /* Use the default router if there is one */
1434                 neigh = neigh_clone(dn_db->router);
1435                 if (neigh) {
1436                         gateway = ((struct dn_neigh *)neigh)->addr;
1437                         goto make_route;
1438                 }
1439
1440                 /* Close eyes and pray */
1441                 gateway = cb->src;
1442                 goto make_route;
1443         default:
1444                 goto e_inval;
1445         }
1446
1447 make_route:
1448         rt = dst_alloc(&dn_dst_ops, out_dev, 1, DST_OBSOLETE_NONE, DST_HOST);
1449         if (rt == NULL)
1450                 goto e_nobufs;
1451
1452         rt->dn_next = NULL;
1453         memset(&rt->fld, 0, sizeof(rt->fld));
1454         rt->rt_saddr      = fld.saddr;
1455         rt->rt_daddr      = fld.daddr;
1456         rt->rt_gateway    = fld.daddr;
1457         if (gateway)
1458                 rt->rt_gateway = gateway;
1459         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1460
1461         rt->rt_dst_map    = fld.daddr;
1462         rt->rt_src_map    = fld.saddr;
1463
1464         rt->fld.saddr        = cb->src;
1465         rt->fld.daddr        = cb->dst;
1466         rt->fld.flowidn_oif  = 0;
1467         rt->fld.flowidn_iif  = in_dev->ifindex;
1468         rt->fld.flowidn_mark = fld.flowidn_mark;
1469
1470         rt->n = neigh;
1471         rt->dst.lastuse = jiffies;
1472         rt->dst.output = dn_rt_bug_out;
1473         switch (res.type) {
1474         case RTN_UNICAST:
1475                 rt->dst.input = dn_forward;
1476                 break;
1477         case RTN_LOCAL:
1478                 rt->dst.output = dn_output;
1479                 rt->dst.input = dn_nsp_rx;
1480                 rt->dst.dev = in_dev;
1481                 flags |= RTCF_LOCAL;
1482                 break;
1483         default:
1484         case RTN_UNREACHABLE:
1485         case RTN_BLACKHOLE:
1486                 rt->dst.input = dst_discard;
1487         }
1488         rt->rt_flags = flags;
1489
1490         err = dn_rt_set_next_hop(rt, &res);
1491         if (err)
1492                 goto e_neighbour;
1493
1494         hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1495         /* dn_insert_route() increments dst->__refcnt */
1496         dn_insert_route(rt, hash, &rt);
1497         skb_dst_set(skb, &rt->dst);
1498
1499 done:
1500         if (neigh)
1501                 neigh_release(neigh);
1502         if (free_res)
1503                 dn_fib_res_put(&res);
1504         dev_put(in_dev);
1505         if (out_dev)
1506                 dev_put(out_dev);
1507 out:
1508         return err;
1509
1510 e_inval:
1511         err = -EINVAL;
1512         goto done;
1513
1514 e_nobufs:
1515         err = -ENOBUFS;
1516         goto done;
1517
1518 e_neighbour:
1519         dst_release_immediate(&rt->dst);
1520         goto done;
1521 }
1522
1523 static int dn_route_input(struct sk_buff *skb)
1524 {
1525         struct dn_route *rt;
1526         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1527         unsigned int hash = dn_hash(cb->src, cb->dst);
1528
1529         if (skb_dst(skb))
1530                 return 0;
1531
1532         rcu_read_lock();
1533         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1534             rt = rcu_dereference(rt->dn_next)) {
1535                 if ((rt->fld.saddr == cb->src) &&
1536                     (rt->fld.daddr == cb->dst) &&
1537                     (rt->fld.flowidn_oif == 0) &&
1538                     (rt->fld.flowidn_mark == skb->mark) &&
1539                     (rt->fld.flowidn_iif == cb->iif)) {
1540                         dst_hold_and_use(&rt->dst, jiffies);
1541                         rcu_read_unlock();
1542                         skb_dst_set(skb, (struct dst_entry *)rt);
1543                         return 0;
1544                 }
1545         }
1546         rcu_read_unlock();
1547
1548         return dn_route_input_slow(skb);
1549 }
1550
1551 static int dn_rt_fill_info(struct sk_buff *skb, u32 portid, u32 seq,
1552                            int event, int nowait, unsigned int flags)
1553 {
1554         struct dn_route *rt = (struct dn_route *)skb_dst(skb);
1555         struct rtmsg *r;
1556         struct nlmsghdr *nlh;
1557         long expires;
1558
1559         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
1560         if (!nlh)
1561                 return -EMSGSIZE;
1562
1563         r = nlmsg_data(nlh);
1564         r->rtm_family = AF_DECnet;
1565         r->rtm_dst_len = 16;
1566         r->rtm_src_len = 0;
1567         r->rtm_tos = 0;
1568         r->rtm_table = RT_TABLE_MAIN;
1569         r->rtm_type = rt->rt_type;
1570         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1571         r->rtm_scope = RT_SCOPE_UNIVERSE;
1572         r->rtm_protocol = RTPROT_UNSPEC;
1573
1574         if (rt->rt_flags & RTCF_NOTIFY)
1575                 r->rtm_flags |= RTM_F_NOTIFY;
1576
1577         if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN) < 0 ||
1578             nla_put_le16(skb, RTA_DST, rt->rt_daddr) < 0)
1579                 goto errout;
1580
1581         if (rt->fld.saddr) {
1582                 r->rtm_src_len = 16;
1583                 if (nla_put_le16(skb, RTA_SRC, rt->fld.saddr) < 0)
1584                         goto errout;
1585         }
1586         if (rt->dst.dev &&
1587             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex) < 0)
1588                 goto errout;
1589
1590         /*
1591          * Note to self - change this if input routes reverse direction when
1592          * they deal only with inputs and not with replies like they do
1593          * currently.
1594          */
1595         if (nla_put_le16(skb, RTA_PREFSRC, rt->rt_local_src) < 0)
1596                 goto errout;
1597
1598         if (rt->rt_daddr != rt->rt_gateway &&
1599             nla_put_le16(skb, RTA_GATEWAY, rt->rt_gateway) < 0)
1600                 goto errout;
1601
1602         if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
1603                 goto errout;
1604
1605         expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
1606         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires,
1607                                rt->dst.error) < 0)
1608                 goto errout;
1609
1610         if (dn_is_input_route(rt) &&
1611             nla_put_u32(skb, RTA_IIF, rt->fld.flowidn_iif) < 0)
1612                 goto errout;
1613
1614         nlmsg_end(skb, nlh);
1615         return 0;
1616
1617 errout:
1618         nlmsg_cancel(skb, nlh);
1619         return -EMSGSIZE;
1620 }
1621
1622 const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
1623         [RTA_DST]               = { .type = NLA_U16 },
1624         [RTA_SRC]               = { .type = NLA_U16 },
1625         [RTA_IIF]               = { .type = NLA_U32 },
1626         [RTA_OIF]               = { .type = NLA_U32 },
1627         [RTA_GATEWAY]           = { .type = NLA_U16 },
1628         [RTA_PRIORITY]          = { .type = NLA_U32 },
1629         [RTA_PREFSRC]           = { .type = NLA_U16 },
1630         [RTA_METRICS]           = { .type = NLA_NESTED },
1631         [RTA_MULTIPATH]         = { .type = NLA_NESTED },
1632         [RTA_TABLE]             = { .type = NLA_U32 },
1633         [RTA_MARK]              = { .type = NLA_U32 },
1634 };
1635
1636 /*
1637  * This is called by both endnodes and routers now.
1638  */
1639 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
1640                              struct netlink_ext_ack *extack)
1641 {
1642         struct net *net = sock_net(in_skb->sk);
1643         struct rtmsg *rtm = nlmsg_data(nlh);
1644         struct dn_route *rt = NULL;
1645         struct dn_skb_cb *cb;
1646         int err;
1647         struct sk_buff *skb;
1648         struct flowidn fld;
1649         struct nlattr *tb[RTA_MAX+1];
1650
1651         if (!net_eq(net, &init_net))
1652                 return -EINVAL;
1653
1654         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_dn_policy,
1655                           extack);
1656         if (err < 0)
1657                 return err;
1658
1659         memset(&fld, 0, sizeof(fld));
1660         fld.flowidn_proto = DNPROTO_NSP;
1661
1662         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1663         if (skb == NULL)
1664                 return -ENOBUFS;
1665         skb_reset_mac_header(skb);
1666         cb = DN_SKB_CB(skb);
1667
1668         if (tb[RTA_SRC])
1669                 fld.saddr = nla_get_le16(tb[RTA_SRC]);
1670
1671         if (tb[RTA_DST])
1672                 fld.daddr = nla_get_le16(tb[RTA_DST]);
1673
1674         if (tb[RTA_IIF])
1675                 fld.flowidn_iif = nla_get_u32(tb[RTA_IIF]);
1676
1677         if (fld.flowidn_iif) {
1678                 struct net_device *dev;
1679                 dev = __dev_get_by_index(&init_net, fld.flowidn_iif);
1680                 if (!dev || !dev->dn_ptr) {
1681                         kfree_skb(skb);
1682                         return -ENODEV;
1683                 }
1684                 skb->protocol = htons(ETH_P_DNA_RT);
1685                 skb->dev = dev;
1686                 cb->src = fld.saddr;
1687                 cb->dst = fld.daddr;
1688                 local_bh_disable();
1689                 err = dn_route_input(skb);
1690                 local_bh_enable();
1691                 memset(cb, 0, sizeof(struct dn_skb_cb));
1692                 rt = (struct dn_route *)skb_dst(skb);
1693                 if (!err && -rt->dst.error)
1694                         err = rt->dst.error;
1695         } else {
1696                 if (tb[RTA_OIF])
1697                         fld.flowidn_oif = nla_get_u32(tb[RTA_OIF]);
1698
1699                 err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
1700         }
1701
1702         skb->dev = NULL;
1703         if (err)
1704                 goto out_free;
1705         skb_dst_set(skb, &rt->dst);
1706         if (rtm->rtm_flags & RTM_F_NOTIFY)
1707                 rt->rt_flags |= RTCF_NOTIFY;
1708
1709         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1710         if (err < 0) {
1711                 err = -EMSGSIZE;
1712                 goto out_free;
1713         }
1714
1715         return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).portid);
1716
1717 out_free:
1718         kfree_skb(skb);
1719         return err;
1720 }
1721
1722 /*
1723  * For routers, this is called from dn_fib_dump, but for endnodes its
1724  * called directly from the rtnetlink dispatch table.
1725  */
1726 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1727 {
1728         struct net *net = sock_net(skb->sk);
1729         struct dn_route *rt;
1730         int h, s_h;
1731         int idx, s_idx;
1732         struct rtmsg *rtm;
1733
1734         if (!net_eq(net, &init_net))
1735                 return 0;
1736
1737         if (nlmsg_len(cb->nlh) < sizeof(struct rtmsg))
1738                 return -EINVAL;
1739
1740         rtm = nlmsg_data(cb->nlh);
1741         if (!(rtm->rtm_flags & RTM_F_CLONED))
1742                 return 0;
1743
1744         s_h = cb->args[0];
1745         s_idx = idx = cb->args[1];
1746         for(h = 0; h <= dn_rt_hash_mask; h++) {
1747                 if (h < s_h)
1748                         continue;
1749                 if (h > s_h)
1750                         s_idx = 0;
1751                 rcu_read_lock_bh();
1752                 for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1753                         rt;
1754                         rt = rcu_dereference_bh(rt->dn_next), idx++) {
1755                         if (idx < s_idx)
1756                                 continue;
1757                         skb_dst_set(skb, dst_clone(&rt->dst));
1758                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).portid,
1759                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1760                                         1, NLM_F_MULTI) < 0) {
1761                                 skb_dst_drop(skb);
1762                                 rcu_read_unlock_bh();
1763                                 goto done;
1764                         }
1765                         skb_dst_drop(skb);
1766                 }
1767                 rcu_read_unlock_bh();
1768         }
1769
1770 done:
1771         cb->args[0] = h;
1772         cb->args[1] = idx;
1773         return skb->len;
1774 }
1775
1776 #ifdef CONFIG_PROC_FS
1777 struct dn_rt_cache_iter_state {
1778         int bucket;
1779 };
1780
1781 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1782 {
1783         struct dn_route *rt = NULL;
1784         struct dn_rt_cache_iter_state *s = seq->private;
1785
1786         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1787                 rcu_read_lock_bh();
1788                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1789                 if (rt)
1790                         break;
1791                 rcu_read_unlock_bh();
1792         }
1793         return rt;
1794 }
1795
1796 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1797 {
1798         struct dn_rt_cache_iter_state *s = seq->private;
1799
1800         rt = rcu_dereference_bh(rt->dn_next);
1801         while (!rt) {
1802                 rcu_read_unlock_bh();
1803                 if (--s->bucket < 0)
1804                         break;
1805                 rcu_read_lock_bh();
1806                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1807         }
1808         return rt;
1809 }
1810
1811 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1812 {
1813         struct dn_route *rt = dn_rt_cache_get_first(seq);
1814
1815         if (rt) {
1816                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1817                         --*pos;
1818         }
1819         return *pos ? NULL : rt;
1820 }
1821
1822 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1823 {
1824         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1825         ++*pos;
1826         return rt;
1827 }
1828
1829 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1830 {
1831         if (v)
1832                 rcu_read_unlock_bh();
1833 }
1834
1835 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1836 {
1837         struct dn_route *rt = v;
1838         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1839
1840         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1841                    rt->dst.dev ? rt->dst.dev->name : "*",
1842                    dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1843                    dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1844                    atomic_read(&rt->dst.__refcnt),
1845                    rt->dst.__use, 0);
1846         return 0;
1847 }
1848
1849 static const struct seq_operations dn_rt_cache_seq_ops = {
1850         .start  = dn_rt_cache_seq_start,
1851         .next   = dn_rt_cache_seq_next,
1852         .stop   = dn_rt_cache_seq_stop,
1853         .show   = dn_rt_cache_seq_show,
1854 };
1855
1856 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1857 {
1858         return seq_open_private(file, &dn_rt_cache_seq_ops,
1859                         sizeof(struct dn_rt_cache_iter_state));
1860 }
1861
1862 static const struct file_operations dn_rt_cache_seq_fops = {
1863         .open    = dn_rt_cache_seq_open,
1864         .read    = seq_read,
1865         .llseek  = seq_lseek,
1866         .release = seq_release_private,
1867 };
1868
1869 #endif /* CONFIG_PROC_FS */
1870
1871 void __init dn_route_init(void)
1872 {
1873         int i, goal, order;
1874
1875         dn_dst_ops.kmem_cachep =
1876                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1877                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1878         dst_entries_init(&dn_dst_ops);
1879         timer_setup(&dn_route_timer, dn_dst_check_expire, 0);
1880         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1881         add_timer(&dn_route_timer);
1882
1883         goal = totalram_pages >> (26 - PAGE_SHIFT);
1884
1885         for(order = 0; (1UL << order) < goal; order++)
1886                 /* NOTHING */;
1887
1888         /*
1889          * Only want 1024 entries max, since the table is very, very unlikely
1890          * to be larger than that.
1891          */
1892         while(order && ((((1UL << order) * PAGE_SIZE) /
1893                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1894                 order--;
1895
1896         do {
1897                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1898                         sizeof(struct dn_rt_hash_bucket);
1899                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1900                         dn_rt_hash_mask--;
1901                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1902                         __get_free_pages(GFP_ATOMIC, order);
1903         } while (dn_rt_hash_table == NULL && --order > 0);
1904
1905         if (!dn_rt_hash_table)
1906                 panic("Failed to allocate DECnet route cache hash table\n");
1907
1908         printk(KERN_INFO
1909                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1910                 dn_rt_hash_mask,
1911                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1912
1913         dn_rt_hash_mask--;
1914         for(i = 0; i <= dn_rt_hash_mask; i++) {
1915                 spin_lock_init(&dn_rt_hash_table[i].lock);
1916                 dn_rt_hash_table[i].chain = NULL;
1917         }
1918
1919         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1920
1921         proc_create("decnet_cache", 0444, init_net.proc_net,
1922                     &dn_rt_cache_seq_fops);
1923
1924 #ifdef CONFIG_DECNET_ROUTER
1925         rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_GETROUTE,
1926                              dn_cache_getroute, dn_fib_dump, 0);
1927 #else
1928         rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_GETROUTE,
1929                              dn_cache_getroute, dn_cache_dump, 0);
1930 #endif
1931 }
1932
1933 void __exit dn_route_cleanup(void)
1934 {
1935         del_timer(&dn_route_timer);
1936         dn_run_flush(0);
1937
1938         remove_proc_entry("decnet_cache", init_net.proc_net);
1939         dst_entries_destroy(&dn_dst_ops);
1940 }
1941