net/decnet/dn_route.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   4  *              operating system.  DECnet is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              DECnet Routing Functions (Endnode and Router)
   8  *
   9  * Authors:     Steve Whitehouse <SteveW@ACM.org>
  10  *              Eduardo Marcelo Serrat <emserrat@geocities.com>
  11  *
  12  * Changes:
  13  *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
  14  *                                 "return-to-sender" bits on outgoing
  15  *                                 packets.
  16  *              Steve Whitehouse : Timeouts for cached routes.
  17  *              Steve Whitehouse : Use dst cache for input routes too.
  18  *              Steve Whitehouse : Fixed error values in dn_send_skb.
  19  *              Steve Whitehouse : Rework routing functions to better fit
  20  *                                 DECnet routing design
  21  *              Alexey Kuznetsov : New SMP locking
  22  *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
  23  *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
  24  *                                 Fixed possible skb leak in rtnetlink funcs.
  25  *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
  26  *                                 Alexey Kuznetsov's finer grained locking
  27  *                                 from ipv4/route.c.
  28  *              Steve Whitehouse : Routing is now starting to look like a
  29  *                                 sensible set of code now, mainly due to
  30  *                                 my copying the IPv4 routing code. The
  31  *                                 hooks here are modified and will continue
  32  *                                 to evolve for a while.
  33  *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
  34  *                                 stuff. Look out raw sockets your days
  35  *                                 are numbered!
  36  *              Steve Whitehouse : Added return-to-sender functions. Added
  37  *                                 backlog congestion level return codes.
  38  *              Steve Whitehouse : Fixed bug where routes were set up with
  39  *                                 no ref count on net devices.
  40  *              Steve Whitehouse : RCU for the route cache
  41  *              Steve Whitehouse : Preparations for the flow cache
  42  *              Steve Whitehouse : Prepare for nonlinear skbs
  43  */
  44
  45 /******************************************************************************
  46     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
  47
  48 *******************************************************************************/
  49
  50 #include <linux/errno.h>
  51 #include <linux/types.h>
  52 #include <linux/socket.h>
  53 #include <linux/in.h>
  54 #include <linux/kernel.h>
  55 #include <linux/sockios.h>
  56 #include <linux/net.h>
  57 #include <linux/netdevice.h>
  58 #include <linux/inet.h>
  59 #include <linux/route.h>
  60 #include <linux/in_route.h>
  61 #include <linux/slab.h>
  62 #include <net/sock.h>
  63 #include <linux/mm.h>
  64 #include <linux/proc_fs.h>
  65 #include <linux/seq_file.h>
  66 #include <linux/init.h>
  67 #include <linux/rtnetlink.h>
  68 #include <linux/string.h>
  69 #include <linux/netfilter_decnet.h>
  70 #include <linux/rcupdate.h>
  71 #include <linux/times.h>
  72 #include <linux/export.h>
  73 #include <asm/errno.h>
  74 #include <net/net_namespace.h>
  75 #include <net/netlink.h>
  76 #include <net/neighbour.h>
  77 #include <net/dst.h>
  78 #include <net/flow.h>
  79 #include <net/fib_rules.h>
  80 #include <net/dn.h>
  81 #include <net/dn_dev.h>
  82 #include <net/dn_nsp.h>
  83 #include <net/dn_route.h>
  84 #include <net/dn_neigh.h>
  85 #include <net/dn_fib.h>
  86
  87 struct dn_rt_hash_bucket
  88 {
  89         struct dn_route __rcu *chain;
  90         spinlock_t lock;
  91 };
  92
  93 extern struct neigh_table dn_neigh_table;
  94
  95
  96 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
  97
  98 static const int dn_rt_min_delay = 2 * HZ;
  99 static const int dn_rt_max_delay = 10 * HZ;
 100 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 101
 102 static unsigned long dn_rt_deadline;
 103
 104 static int dn_dst_gc(struct dst_ops *ops);
 105 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 106 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst);
 107 static unsigned int dn_dst_mtu(const struct dst_entry *dst);
 108 static void dn_dst_destroy(struct dst_entry *);
 109 static void dn_dst_ifdown(struct dst_entry *, struct net_device *dev, int how);
 110 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 111 static void dn_dst_link_failure(struct sk_buff *);
 112 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
 113                                struct sk_buff *skb , u32 mtu,
 114                                bool confirm_neigh);
 115 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
 116                             struct sk_buff *skb);
 117 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
 118                                              struct sk_buff *skb,
 119                                              const void *daddr);
 120 static int dn_route_input(struct sk_buff *);
 121 static void dn_run_flush(struct timer_list *unused);
 122
 123 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 124 static unsigned int dn_rt_hash_mask;
 125
 126 static struct timer_list dn_route_timer;
 127 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush);
 128 int decnet_dst_gc_interval = 2;
 129
 130 static struct dst_ops dn_dst_ops = {
 131         .family =               PF_DECnet,
 132         .gc_thresh =            128,
 133         .gc =                   dn_dst_gc,
 134         .check =                dn_dst_check,
 135         .default_advmss =       dn_dst_default_advmss,
 136         .mtu =                  dn_dst_mtu,
 137         .cow_metrics =          dst_cow_metrics_generic,
 138         .destroy =              dn_dst_destroy,
 139         .ifdown =               dn_dst_ifdown,
 140         .negative_advice =      dn_dst_negative_advice,
 141         .link_failure =         dn_dst_link_failure,
 142         .update_pmtu =          dn_dst_update_pmtu,
 143         .redirect =             dn_dst_redirect,
 144         .neigh_lookup =         dn_dst_neigh_lookup,
 145 };
 146
 147 static void dn_dst_destroy(struct dst_entry *dst)
 148 {
 149         struct dn_route *rt = (struct dn_route *) dst;
 150
 151         if (rt->n)
 152                 neigh_release(rt->n);
 153         dst_destroy_metrics_generic(dst);
 154 }
 155
 156 static void dn_dst_ifdown(struct dst_entry *dst, struct net_device *dev, int how)
 157 {
 158         if (how) {
 159                 struct dn_route *rt = (struct dn_route *) dst;
 160                 struct neighbour *n = rt->n;
 161
 162                 if (n && n->dev == dev) {
 163                         n->dev = dev_net(dev)->loopback_dev;
 164                         dev_hold(n->dev);
 165                         dev_put(dev);
 166                 }
 167         }
 168 }
 169
 170 static __inline__ unsigned int dn_hash(__le16 src, __le16 dst)
 171 {
 172         __u16 tmp = (__u16 __force)(src ^ dst);
 173         tmp ^= (tmp >> 3);
 174         tmp ^= (tmp >> 5);
 175         tmp ^= (tmp >> 10);
 176         return dn_rt_hash_mask & (unsigned int)tmp;
 177 }
 178
 179 static void dn_dst_check_expire(struct timer_list *unused)
 180 {
 181         int i;
 182         struct dn_route *rt;
 183         struct dn_route __rcu **rtp;
 184         unsigned long now = jiffies;
 185         unsigned long expire = 120 * HZ;
 186
 187         for (i = 0; i <= dn_rt_hash_mask; i++) {
 188                 rtp = &dn_rt_hash_table[i].chain;
 189
 190                 spin_lock(&dn_rt_hash_table[i].lock);
 191                 while ((rt = rcu_dereference_protected(*rtp,
 192                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 193                         if (atomic_read(&rt->dst.__refcnt) > 1 ||
 194                             (now - rt->dst.lastuse) < expire) {
 195                                 rtp = &rt->dn_next;
 196                                 continue;
 197                         }
 198                         *rtp = rt->dn_next;
 199                         rt->dn_next = NULL;
 200                         dst_dev_put(&rt->dst);
 201                         dst_release(&rt->dst);
 202                 }
 203                 spin_unlock(&dn_rt_hash_table[i].lock);
 204
 205                 if ((jiffies - now) > 0)
 206                         break;
 207         }
 208
 209         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 210 }
 211
 212 static int dn_dst_gc(struct dst_ops *ops)
 213 {
 214         struct dn_route *rt;
 215         struct dn_route __rcu **rtp;
 216         int i;
 217         unsigned long now = jiffies;
 218         unsigned long expire = 10 * HZ;
 219
 220         for (i = 0; i <= dn_rt_hash_mask; i++) {
 221
 222                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 223                 rtp = &dn_rt_hash_table[i].chain;
 224
 225                 while ((rt = rcu_dereference_protected(*rtp,
 226                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 227                         if (atomic_read(&rt->dst.__refcnt) > 1 ||
 228                             (now - rt->dst.lastuse) < expire) {
 229                                 rtp = &rt->dn_next;
 230                                 continue;
 231                         }
 232                         *rtp = rt->dn_next;
 233                         rt->dn_next = NULL;
 234                         dst_dev_put(&rt->dst);
 235                         dst_release(&rt->dst);
 236                         break;
 237                 }
 238                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 239         }
 240
 241         return 0;
 242 }
 243
 244 /*
 245  * The decnet standards don't impose a particular minimum mtu, what they
 246  * do insist on is that the routing layer accepts a datagram of at least
 247  * 230 bytes long. Here we have to subtract the routing header length from
 248  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 249  * assume the worst and use a long header size.
 250  *
 251  * We update both the mtu and the advertised mss (i.e. the segment size we
 252  * advertise to the other end).
 253  */
 254 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
 255                                struct sk_buff *skb, u32 mtu,
 256                                bool confirm_neigh)
 257 {
 258         struct dn_route *rt = (struct dn_route *) dst;
 259         struct neighbour *n = rt->n;
 260         u32 min_mtu = 230;
 261         struct dn_dev *dn;
 262
 263         dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL;
 264
 265         if (dn && dn->use_long == 0)
 266                 min_mtu -= 6;
 267         else
 268                 min_mtu -= 21;
 269
 270         if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
 271                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
 272                         dst_metric_set(dst, RTAX_MTU, mtu);
 273                         dst_set_expires(dst, dn_rt_mtu_expires);
 274                 }
 275                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 276                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 277                         u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
 278                         if (!existing_mss || existing_mss > mss)
 279                                 dst_metric_set(dst, RTAX_ADVMSS, mss);
 280                 }
 281         }
 282 }
 283
 284 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
 285                             struct sk_buff *skb)
 286 {
 287 }
 288
 289 /*
 290  * When a route has been marked obsolete. (e.g. routing cache flush)
 291  */
 292 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 293 {
 294         return NULL;
 295 }
 296
 297 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 298 {
 299         dst_release(dst);
 300         return NULL;
 301 }
 302
 303 static void dn_dst_link_failure(struct sk_buff *skb)
 304 {
 305 }
 306
 307 static inline int compare_keys(struct flowidn *fl1, struct flowidn *fl2)
 308 {
 309         return ((fl1->daddr ^ fl2->daddr) |
 310                 (fl1->saddr ^ fl2->saddr) |
 311                 (fl1->flowidn_mark ^ fl2->flowidn_mark) |
 312                 (fl1->flowidn_scope ^ fl2->flowidn_scope) |
 313                 (fl1->flowidn_oif ^ fl2->flowidn_oif) |
 314                 (fl1->flowidn_iif ^ fl2->flowidn_iif)) == 0;
 315 }
 316
 317 static int dn_insert_route(struct dn_route *rt, unsigned int hash, struct dn_route **rp)
 318 {
 319         struct dn_route *rth;
 320         struct dn_route __rcu **rthp;
 321         unsigned long now = jiffies;
 322
 323         rthp = &dn_rt_hash_table[hash].chain;
 324
 325         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 326         while ((rth = rcu_dereference_protected(*rthp,
 327                                                 lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
 328                 if (compare_keys(&rth->fld, &rt->fld)) {
 329                         /* Put it first */
 330                         *rthp = rth->dn_next;
 331                         rcu_assign_pointer(rth->dn_next,
 332                                            dn_rt_hash_table[hash].chain);
 333                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 334
 335                         dst_hold_and_use(&rth->dst, now);
 336                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 337
 338                         dst_release_immediate(&rt->dst);
 339                         *rp = rth;
 340                         return 0;
 341                 }
 342                 rthp = &rth->dn_next;
 343         }
 344
 345         rcu_assign_pointer(rt->dn_next, dn_rt_hash_table[hash].chain);
 346         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 347
 348         dst_hold_and_use(&rt->dst, now);
 349         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 350         *rp = rt;
 351         return 0;
 352 }
 353
 354 static void dn_run_flush(struct timer_list *unused)
 355 {
 356         int i;
 357         struct dn_route *rt, *next;
 358
 359         for (i = 0; i < dn_rt_hash_mask; i++) {
 360                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 361
 362                 if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
 363                         goto nothing_to_declare;
 364
 365                 for(; rt; rt = next) {
 366                         next = rcu_dereference_raw(rt->dn_next);
 367                         RCU_INIT_POINTER(rt->dn_next, NULL);
 368                         dst_dev_put(&rt->dst);
 369                         dst_release(&rt->dst);
 370                 }
 371
 372 nothing_to_declare:
 373                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 374         }
 375 }
 376
 377 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 378
 379 void dn_rt_cache_flush(int delay)
 380 {
 381         unsigned long now = jiffies;
 382         int user_mode = !in_interrupt();
 383
 384         if (delay < 0)
 385                 delay = dn_rt_min_delay;
 386
 387         spin_lock_bh(&dn_rt_flush_lock);
 388
 389         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 390                 long tmo = (long)(dn_rt_deadline - now);
 391
 392                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 393                         tmo = 0;
 394
 395                 if (delay > tmo)
 396                         delay = tmo;
 397         }
 398
 399         if (delay <= 0) {
 400                 spin_unlock_bh(&dn_rt_flush_lock);
 401                 dn_run_flush(NULL);
 402                 return;
 403         }
 404
 405         if (dn_rt_deadline == 0)
 406                 dn_rt_deadline = now + dn_rt_max_delay;
 407
 408         dn_rt_flush_timer.expires = now + delay;
 409         add_timer(&dn_rt_flush_timer);
 410         spin_unlock_bh(&dn_rt_flush_lock);
 411 }
 412
 413 /**
 414  * dn_return_short - Return a short packet to its sender
 415  * @skb: The packet to return
 416  *
 417  */
 418 static int dn_return_short(struct sk_buff *skb)
 419 {
 420         struct dn_skb_cb *cb;
 421         unsigned char *ptr;
 422         __le16 *src;
 423         __le16 *dst;
 424
 425         /* Add back headers */
 426         skb_push(skb, skb->data - skb_network_header(skb));
 427
 428         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 429                 return NET_RX_DROP;
 430
 431         cb = DN_SKB_CB(skb);
 432         /* Skip packet length and point to flags */
 433         ptr = skb->data + 2;
 434         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 435
 436         dst = (__le16 *)ptr;
 437         ptr += 2;
 438         src = (__le16 *)ptr;
 439         ptr += 2;
 440         *ptr = 0; /* Zero hop count */
 441
 442         swap(*src, *dst);
 443
 444         skb->pkt_type = PACKET_OUTGOING;
 445         dn_rt_finish_output(skb, NULL, NULL);
 446         return NET_RX_SUCCESS;
 447 }
 448
 449 /**
 450  * dn_return_long - Return a long packet to its sender
 451  * @skb: The long format packet to return
 452  *
 453  */
 454 static int dn_return_long(struct sk_buff *skb)
 455 {
 456         struct dn_skb_cb *cb;
 457         unsigned char *ptr;
 458         unsigned char *src_addr, *dst_addr;
 459         unsigned char tmp[ETH_ALEN];
 460
 461         /* Add back all headers */
 462         skb_push(skb, skb->data - skb_network_header(skb));
 463
 464         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 465                 return NET_RX_DROP;
 466
 467         cb = DN_SKB_CB(skb);
 468         /* Ignore packet length and point to flags */
 469         ptr = skb->data + 2;
 470
 471         /* Skip padding */
 472         if (*ptr & DN_RT_F_PF) {
 473                 char padlen = (*ptr & ~DN_RT_F_PF);
 474                 ptr += padlen;
 475         }
 476
 477         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 478         ptr += 2;
 479         dst_addr = ptr;
 480         ptr += 8;
 481         src_addr = ptr;
 482         ptr += 6;
 483         *ptr = 0; /* Zero hop count */
 484
 485         /* Swap source and destination */
 486         memcpy(tmp, src_addr, ETH_ALEN);
 487         memcpy(src_addr, dst_addr, ETH_ALEN);
 488         memcpy(dst_addr, tmp, ETH_ALEN);
 489
 490         skb->pkt_type = PACKET_OUTGOING;
 491         dn_rt_finish_output(skb, dst_addr, src_addr);
 492         return NET_RX_SUCCESS;
 493 }
 494
 495 /**
 496  * dn_route_rx_packet - Try and find a route for an incoming packet
 497  * @net: The applicable net namespace
 498  * @sk: Socket packet transmitted on
 499  * @skb: The packet to find a route for
 500  *
 501  * Returns: result of input function if route is found, error code otherwise
 502  */
 503 static int dn_route_rx_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
 504 {
 505         struct dn_skb_cb *cb;
 506         int err;
 507
 508         if ((err = dn_route_input(skb)) == 0)
 509                 return dst_input(skb);
 510
 511         cb = DN_SKB_CB(skb);
 512         if (decnet_debug_level & 4) {
 513                 char *devname = skb->dev ? skb->dev->name : "???";
 514
 515                 printk(KERN_DEBUG
 516                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 517                         (int)cb->rt_flags, devname, skb->len,
 518                         le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
 519                         err, skb->pkt_type);
 520         }
 521
 522         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 523                 switch (cb->rt_flags & DN_RT_PKT_MSK) {
 524                 case DN_RT_PKT_SHORT:
 525                         return dn_return_short(skb);
 526                 case DN_RT_PKT_LONG:
 527                         return dn_return_long(skb);
 528                 }
 529         }
 530
 531         kfree_skb(skb);
 532         return NET_RX_DROP;
 533 }
 534
 535 static int dn_route_rx_long(struct sk_buff *skb)
 536 {
 537         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 538         unsigned char *ptr = skb->data;
 539
 540         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 541                 goto drop_it;
 542
 543         skb_pull(skb, 20);
 544         skb_reset_transport_header(skb);
 545
 546         /* Destination info */
 547         ptr += 2;
 548         cb->dst = dn_eth2dn(ptr);
 549         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 550                 goto drop_it;
 551         ptr += 6;
 552
 553
 554         /* Source info */
 555         ptr += 2;
 556         cb->src = dn_eth2dn(ptr);
 557         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 558                 goto drop_it;
 559         ptr += 6;
 560         /* Other junk */
 561         ptr++;
 562         cb->hops = *ptr++; /* Visit Count */
 563
 564         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
 565                        &init_net, NULL, skb, skb->dev, NULL,
 566                        dn_route_rx_packet);
 567
 568 drop_it:
 569         kfree_skb(skb);
 570         return NET_RX_DROP;
 571 }
 572
 573
 574
 575 static int dn_route_rx_short(struct sk_buff *skb)
 576 {
 577         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 578         unsigned char *ptr = skb->data;
 579
 580         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 581                 goto drop_it;
 582
 583         skb_pull(skb, 5);
 584         skb_reset_transport_header(skb);
 585
 586         cb->dst = *(__le16 *)ptr;
 587         ptr += 2;
 588         cb->src = *(__le16 *)ptr;
 589         ptr += 2;
 590         cb->hops = *ptr & 0x3f;
 591
 592         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
 593                        &init_net, NULL, skb, skb->dev, NULL,
 594                        dn_route_rx_packet);
 595
 596 drop_it:
 597         kfree_skb(skb);
 598         return NET_RX_DROP;
 599 }
 600
 601 static int dn_route_discard(struct net *net, struct sock *sk, struct sk_buff *skb)
 602 {
 603         /*
 604          * I know we drop the packet here, but thats considered success in
 605          * this case
 606          */
 607         kfree_skb(skb);
 608         return NET_RX_SUCCESS;
 609 }
 610
 611 static int dn_route_ptp_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
 612 {
 613         dn_dev_hello(skb);
 614         dn_neigh_pointopoint_hello(skb);
 615         return NET_RX_SUCCESS;
 616 }
 617
 618 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 619 {
 620         struct dn_skb_cb *cb;
 621         unsigned char flags = 0;
 622         __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 623         struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
 624         unsigned char padlen = 0;
 625
 626         if (!net_eq(dev_net(dev), &init_net))
 627                 goto dump_it;
 628
 629         if (dn == NULL)
 630                 goto dump_it;
 631
 632         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 633                 goto out;
 634
 635         if (!pskb_may_pull(skb, 3))
 636                 goto dump_it;
 637
 638         skb_pull(skb, 2);
 639
 640         if (len > skb->len)
 641                 goto dump_it;
 642
 643         skb_trim(skb, len);
 644
 645         flags = *skb->data;
 646
 647         cb = DN_SKB_CB(skb);
 648         cb->stamp = jiffies;
 649         cb->iif = dev->ifindex;
 650
 651         /*
 652          * If we have padding, remove it.
 653          */
 654         if (flags & DN_RT_F_PF) {
 655                 padlen = flags & ~DN_RT_F_PF;
 656                 if (!pskb_may_pull(skb, padlen + 1))
 657                         goto dump_it;
 658                 skb_pull(skb, padlen);
 659                 flags = *skb->data;
 660         }
 661
 662         skb_reset_network_header(skb);
 663
 664         /*
 665          * Weed out future version DECnet
 666          */
 667         if (flags & DN_RT_F_VER)
 668                 goto dump_it;
 669
 670         cb->rt_flags = flags;
 671
 672         if (decnet_debug_level & 1)
 673                 printk(KERN_DEBUG
 674                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 675                         (int)flags, dev->name, len, skb->len,
 676                         padlen);
 677
 678         if (flags & DN_RT_PKT_CNTL) {
 679                 if (unlikely(skb_linearize(skb)))
 680                         goto dump_it;
 681
 682                 switch (flags & DN_RT_CNTL_MSK) {
 683                 case DN_RT_PKT_INIT:
 684                         dn_dev_init_pkt(skb);
 685                         break;
 686                 case DN_RT_PKT_VERI:
 687                         dn_dev_veri_pkt(skb);
 688                         break;
 689                 }
 690
 691                 if (dn->parms.state != DN_DEV_S_RU)
 692                         goto dump_it;
 693
 694                 switch (flags & DN_RT_CNTL_MSK) {
 695                 case DN_RT_PKT_HELO:
 696                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 697                                        &init_net, NULL, skb, skb->dev, NULL,
 698                                        dn_route_ptp_hello);
 699
 700                 case DN_RT_PKT_L1RT:
 701                 case DN_RT_PKT_L2RT:
 702                         return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
 703                                        &init_net, NULL, skb, skb->dev, NULL,
 704                                        dn_route_discard);
 705                 case DN_RT_PKT_ERTH:
 706                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 707                                        &init_net, NULL, skb, skb->dev, NULL,
 708                                        dn_neigh_router_hello);
 709
 710                 case DN_RT_PKT_EEDH:
 711                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 712                                        &init_net, NULL, skb, skb->dev, NULL,
 713                                        dn_neigh_endnode_hello);
 714                 }
 715         } else {
 716                 if (dn->parms.state != DN_DEV_S_RU)
 717                         goto dump_it;
 718
 719                 skb_pull(skb, 1); /* Pull flags */
 720
 721                 switch (flags & DN_RT_PKT_MSK) {
 722                 case DN_RT_PKT_LONG:
 723                         return dn_route_rx_long(skb);
 724                 case DN_RT_PKT_SHORT:
 725                         return dn_route_rx_short(skb);
 726                 }
 727         }
 728
 729 dump_it:
 730         kfree_skb(skb);
 731 out:
 732         return NET_RX_DROP;
 733 }
 734
 735 static int dn_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 736 {
 737         struct dst_entry *dst = skb_dst(skb);
 738         struct dn_route *rt = (struct dn_route *)dst;
 739         struct net_device *dev = dst->dev;
 740         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 741
 742         int err = -EINVAL;
 743
 744         if (rt->n == NULL)
 745                 goto error;
 746
 747         skb->dev = dev;
 748
 749         cb->src = rt->rt_saddr;
 750         cb->dst = rt->rt_daddr;
 751
 752         /*
 753          * Always set the Intra-Ethernet bit on all outgoing packets
 754          * originated on this node. Only valid flag from upper layers
 755          * is return-to-sender-requested. Set hop count to 0 too.
 756          */
 757         cb->rt_flags &= ~DN_RT_F_RQR;
 758         cb->rt_flags |= DN_RT_F_IE;
 759         cb->hops = 0;
 760
 761         return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT,
 762                        &init_net, sk, skb, NULL, dev,
 763                        dn_to_neigh_output);
 764
 765 error:
 766         net_dbg_ratelimited("dn_output: This should not happen\n");
 767
 768         kfree_skb(skb);
 769
 770         return err;
 771 }
 772
 773 static int dn_forward(struct sk_buff *skb)
 774 {
 775         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 776         struct dst_entry *dst = skb_dst(skb);
 777         struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
 778         struct dn_route *rt;
 779         int header_len;
 780         struct net_device *dev = skb->dev;
 781
 782         if (skb->pkt_type != PACKET_HOST)
 783                 goto drop;
 784
 785         /* Ensure that we have enough space for headers */
 786         rt = (struct dn_route *)skb_dst(skb);
 787         header_len = dn_db->use_long ? 21 : 6;
 788         if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
 789                 goto drop;
 790
 791         /*
 792          * Hop count exceeded.
 793          */
 794         if (++cb->hops > 30)
 795                 goto drop;
 796
 797         skb->dev = rt->dst.dev;
 798
 799         /*
 800          * If packet goes out same interface it came in on, then set
 801          * the Intra-Ethernet bit. This has no effect for short
 802          * packets, so we don't need to test for them here.
 803          */
 804         cb->rt_flags &= ~DN_RT_F_IE;
 805         if (rt->rt_flags & RTCF_DOREDIRECT)
 806                 cb->rt_flags |= DN_RT_F_IE;
 807
 808         return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD,
 809                        &init_net, NULL, skb, dev, skb->dev,
 810                        dn_to_neigh_output);
 811
 812 drop:
 813         kfree_skb(skb);
 814         return NET_RX_DROP;
 815 }
 816
 817 /*
 818  * Used to catch bugs. This should never normally get
 819  * called.
 820  */
 821 static int dn_rt_bug_out(struct net *net, struct sock *sk, struct sk_buff *skb)
 822 {
 823         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 824
 825         net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
 826                             le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 827
 828         kfree_skb(skb);
 829
 830         return NET_RX_DROP;
 831 }
 832
 833 static int dn_rt_bug(struct sk_buff *skb)
 834 {
 835         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 836
 837         net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
 838                             le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 839
 840         kfree_skb(skb);
 841
 842         return NET_RX_DROP;
 843 }
 844
 845 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
 846 {
 847         return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
 848 }
 849
 850 static unsigned int dn_dst_mtu(const struct dst_entry *dst)
 851 {
 852         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
 853
 854         return mtu ? : dst->dev->mtu;
 855 }
 856
 857 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
 858                                              struct sk_buff *skb,
 859                                              const void *daddr)
 860 {
 861         return __neigh_lookup_errno(&dn_neigh_table, daddr, dst->dev);
 862 }
 863
 864 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 865 {
 866         struct dn_fib_info *fi = res->fi;
 867         struct net_device *dev = rt->dst.dev;
 868         unsigned int mss_metric;
 869         struct neighbour *n;
 870
 871         if (fi) {
 872                 if (DN_FIB_RES_GW(*res) &&
 873                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 874                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 875                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
 876         }
 877         rt->rt_type = res->type;
 878
 879         if (dev != NULL && rt->n == NULL) {
 880                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 881                 if (IS_ERR(n))
 882                         return PTR_ERR(n);
 883                 rt->n = n;
 884         }
 885
 886         if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
 887                 dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
 888         mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
 889         if (mss_metric) {
 890                 unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
 891                 if (mss_metric > mss)
 892                         dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
 893         }
 894         return 0;
 895 }
 896
 897 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 898 {
 899         __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 900         int match = 16;
 901         while(tmp) {
 902                 tmp >>= 1;
 903                 match--;
 904         }
 905         return match;
 906 }
 907
 908 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 909 {
 910         __le16 saddr = 0;
 911         struct dn_dev *dn_db;
 912         struct dn_ifaddr *ifa;
 913         int best_match = 0;
 914         int ret;
 915
 916         rcu_read_lock();
 917         dn_db = rcu_dereference(dev->dn_ptr);
 918         for (ifa = rcu_dereference(dn_db->ifa_list);
 919              ifa != NULL;
 920              ifa = rcu_dereference(ifa->ifa_next)) {
 921                 if (ifa->ifa_scope > scope)
 922                         continue;
 923                 if (!daddr) {
 924                         saddr = ifa->ifa_local;
 925                         break;
 926                 }
 927                 ret = dn_match_addr(daddr, ifa->ifa_local);
 928                 if (ret > best_match)
 929                         saddr = ifa->ifa_local;
 930                 if (best_match == 0)
 931                         saddr = ifa->ifa_local;
 932         }
 933         rcu_read_unlock();
 934
 935         return saddr;
 936 }
 937
 938 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 939 {
 940         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 941 }
 942
 943 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 944 {
 945         __le16 mask = dnet_make_mask(res->prefixlen);
 946         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 947 }
 948
 949 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowidn *oldflp, int try_hard)
 950 {
 951         struct flowidn fld = {
 952                 .daddr = oldflp->daddr,
 953                 .saddr = oldflp->saddr,
 954                 .flowidn_scope = RT_SCOPE_UNIVERSE,
 955                 .flowidn_mark = oldflp->flowidn_mark,
 956                 .flowidn_iif = LOOPBACK_IFINDEX,
 957                 .flowidn_oif = oldflp->flowidn_oif,
 958         };
 959         struct dn_route *rt = NULL;
 960         struct net_device *dev_out = NULL, *dev;
 961         struct neighbour *neigh = NULL;
 962         unsigned int hash;
 963         unsigned int flags = 0;
 964         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 965         int err;
 966         int free_res = 0;
 967         __le16 gateway = 0;
 968
 969         if (decnet_debug_level & 16)
 970                 printk(KERN_DEBUG
 971                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 972                        " iif=%d oif=%d\n", le16_to_cpu(oldflp->daddr),
 973                        le16_to_cpu(oldflp->saddr),
 974                        oldflp->flowidn_mark, LOOPBACK_IFINDEX,
 975                        oldflp->flowidn_oif);
 976
 977         /* If we have an output interface, verify its a DECnet device */
 978         if (oldflp->flowidn_oif) {
 979                 dev_out = dev_get_by_index(&init_net, oldflp->flowidn_oif);
 980                 err = -ENODEV;
 981                 if (dev_out && dev_out->dn_ptr == NULL) {
 982                         dev_put(dev_out);
 983                         dev_out = NULL;
 984                 }
 985                 if (dev_out == NULL)
 986                         goto out;
 987         }
 988
 989         /* If we have a source address, verify that its a local address */
 990         if (oldflp->saddr) {
 991                 err = -EADDRNOTAVAIL;
 992
 993                 if (dev_out) {
 994                         if (dn_dev_islocal(dev_out, oldflp->saddr))
 995                                 goto source_ok;
 996                         dev_put(dev_out);
 997                         goto out;
 998                 }
 999                 rcu_read_lock();
1000                 for_each_netdev_rcu(&init_net, dev) {
1001                         if (!dev->dn_ptr)
1002                                 continue;
1003                         if (!dn_dev_islocal(dev, oldflp->saddr))
1004                                 continue;
1005                         if ((dev->flags & IFF_LOOPBACK) &&
1006                             oldflp->daddr &&
1007                             !dn_dev_islocal(dev, oldflp->daddr))
1008                                 continue;
1009
1010                         dev_out = dev;
1011                         break;
1012                 }
1013                 rcu_read_unlock();
1014                 if (dev_out == NULL)
1015                         goto out;
1016                 dev_hold(dev_out);
1017 source_ok:
1018                 ;
1019         }
1020
1021         /* No destination? Assume its local */
1022         if (!fld.daddr) {
1023                 fld.daddr = fld.saddr;
1024
1025                 if (dev_out)
1026                         dev_put(dev_out);
1027                 err = -EINVAL;
1028                 dev_out = init_net.loopback_dev;
1029                 if (!dev_out->dn_ptr)
1030                         goto out;
1031                 err = -EADDRNOTAVAIL;
1032                 dev_hold(dev_out);
1033                 if (!fld.daddr) {
1034                         fld.daddr =
1035                         fld.saddr = dnet_select_source(dev_out, 0,
1036                                                        RT_SCOPE_HOST);
1037                         if (!fld.daddr)
1038                                 goto out;
1039                 }
1040                 fld.flowidn_oif = LOOPBACK_IFINDEX;
1041                 res.type = RTN_LOCAL;
1042                 goto make_route;
1043         }
1044
1045         if (decnet_debug_level & 16)
1046                 printk(KERN_DEBUG
1047                        "dn_route_output_slow: initial checks complete."
1048                        " dst=%04x src=%04x oif=%d try_hard=%d\n",
1049                        le16_to_cpu(fld.daddr), le16_to_cpu(fld.saddr),
1050                        fld.flowidn_oif, try_hard);
1051
1052         /*
1053          * N.B. If the kernel is compiled without router support then
1054          * dn_fib_lookup() will evaluate to non-zero so this if () block
1055          * will always be executed.
1056          */
1057         err = -ESRCH;
1058         if (try_hard || (err = dn_fib_lookup(&fld, &res)) != 0) {
1059                 struct dn_dev *dn_db;
1060                 if (err != -ESRCH)
1061                         goto out;
1062                 /*
1063                  * Here the fallback is basically the standard algorithm for
1064                  * routing in endnodes which is described in the DECnet routing
1065                  * docs
1066                  *
1067                  * If we are not trying hard, look in neighbour cache.
1068                  * The result is tested to ensure that if a specific output
1069                  * device/source address was requested, then we honour that
1070                  * here
1071                  */
1072                 if (!try_hard) {
1073                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fld.daddr);
1074                         if (neigh) {
1075                                 if ((oldflp->flowidn_oif &&
1076                                     (neigh->dev->ifindex != oldflp->flowidn_oif)) ||
1077                                     (oldflp->saddr &&
1078                                     (!dn_dev_islocal(neigh->dev,
1079                                                      oldflp->saddr)))) {
1080                                         neigh_release(neigh);
1081                                         neigh = NULL;
1082                                 } else {
1083                                         if (dev_out)
1084                                                 dev_put(dev_out);
1085                                         if (dn_dev_islocal(neigh->dev, fld.daddr)) {
1086                                                 dev_out = init_net.loopback_dev;
1087                                                 res.type = RTN_LOCAL;
1088                                         } else {
1089                                                 dev_out = neigh->dev;
1090                                         }
1091                                         dev_hold(dev_out);
1092                                         goto select_source;
1093                                 }
1094                         }
1095                 }
1096
1097                 /* Not there? Perhaps its a local address */
1098                 if (dev_out == NULL)
1099                         dev_out = dn_dev_get_default();
1100                 err = -ENODEV;
1101                 if (dev_out == NULL)
1102                         goto out;
1103                 dn_db = rcu_dereference_raw(dev_out->dn_ptr);
1104                 if (!dn_db)
1105                         goto e_inval;
1106                 /* Possible improvement - check all devices for local addr */
1107                 if (dn_dev_islocal(dev_out, fld.daddr)) {
1108                         dev_put(dev_out);
1109                         dev_out = init_net.loopback_dev;
1110                         dev_hold(dev_out);
1111                         res.type = RTN_LOCAL;
1112                         goto select_source;
1113                 }
1114                 /* Not local either.... try sending it to the default router */
1115                 neigh = neigh_clone(dn_db->router);
1116                 BUG_ON(neigh && neigh->dev != dev_out);
1117
1118                 /* Ok then, we assume its directly connected and move on */
1119 select_source:
1120                 if (neigh)
1121                         gateway = ((struct dn_neigh *)neigh)->addr;
1122                 if (gateway == 0)
1123                         gateway = fld.daddr;
1124                 if (fld.saddr == 0) {
1125                         fld.saddr = dnet_select_source(dev_out, gateway,
1126                                                        res.type == RTN_LOCAL ?
1127                                                        RT_SCOPE_HOST :
1128                                                        RT_SCOPE_LINK);
1129                         if (fld.saddr == 0 && res.type != RTN_LOCAL)
1130                                 goto e_addr;
1131                 }
1132                 fld.flowidn_oif = dev_out->ifindex;
1133                 goto make_route;
1134         }
1135         free_res = 1;
1136
1137         if (res.type == RTN_NAT)
1138                 goto e_inval;
1139
1140         if (res.type == RTN_LOCAL) {
1141                 if (!fld.saddr)
1142                         fld.saddr = fld.daddr;
1143                 if (dev_out)
1144                         dev_put(dev_out);
1145                 dev_out = init_net.loopback_dev;
1146                 dev_hold(dev_out);
1147                 if (!dev_out->dn_ptr)
1148                         goto e_inval;
1149                 fld.flowidn_oif = dev_out->ifindex;
1150                 if (res.fi)
1151                         dn_fib_info_put(res.fi);
1152                 res.fi = NULL;
1153                 goto make_route;
1154         }
1155
1156         if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1157                 dn_fib_select_multipath(&fld, &res);
1158
1159         /*
1160          * We could add some logic to deal with default routes here and
1161          * get rid of some of the special casing above.
1162          */
1163
1164         if (!fld.saddr)
1165                 fld.saddr = DN_FIB_RES_PREFSRC(res);
1166
1167         if (dev_out)
1168                 dev_put(dev_out);
1169         dev_out = DN_FIB_RES_DEV(res);
1170         dev_hold(dev_out);
1171         fld.flowidn_oif = dev_out->ifindex;
1172         gateway = DN_FIB_RES_GW(res);
1173
1174 make_route:
1175         if (dev_out->flags & IFF_LOOPBACK)
1176                 flags |= RTCF_LOCAL;
1177
1178         rt = dst_alloc(&dn_dst_ops, dev_out, 0, DST_OBSOLETE_NONE, 0);
1179         if (rt == NULL)
1180                 goto e_nobufs;
1181
1182         rt->dn_next = NULL;
1183         memset(&rt->fld, 0, sizeof(rt->fld));
1184         rt->fld.saddr        = oldflp->saddr;
1185         rt->fld.daddr        = oldflp->daddr;
1186         rt->fld.flowidn_oif  = oldflp->flowidn_oif;
1187         rt->fld.flowidn_iif  = 0;
1188         rt->fld.flowidn_mark = oldflp->flowidn_mark;
1189
1190         rt->rt_saddr      = fld.saddr;
1191         rt->rt_daddr      = fld.daddr;
1192         rt->rt_gateway    = gateway ? gateway : fld.daddr;
1193         rt->rt_local_src  = fld.saddr;
1194
1195         rt->rt_dst_map    = fld.daddr;
1196         rt->rt_src_map    = fld.saddr;
1197
1198         rt->n = neigh;
1199         neigh = NULL;
1200
1201         rt->dst.lastuse = jiffies;
1202         rt->dst.output  = dn_output;
1203         rt->dst.input   = dn_rt_bug;
1204         rt->rt_flags      = flags;
1205         if (flags & RTCF_LOCAL)
1206                 rt->dst.input = dn_nsp_rx;
1207
1208         err = dn_rt_set_next_hop(rt, &res);
1209         if (err)
1210                 goto e_neighbour;
1211
1212         hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1213         /* dn_insert_route() increments dst->__refcnt */
1214         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1215
1216 done:
1217         if (neigh)
1218                 neigh_release(neigh);
1219         if (free_res)
1220                 dn_fib_res_put(&res);
1221         if (dev_out)
1222                 dev_put(dev_out);
1223 out:
1224         return err;
1225
1226 e_addr:
1227         err = -EADDRNOTAVAIL;
1228         goto done;
1229 e_inval:
1230         err = -EINVAL;
1231         goto done;
1232 e_nobufs:
1233         err = -ENOBUFS;
1234         goto done;
1235 e_neighbour:
1236         dst_release_immediate(&rt->dst);
1237         goto e_nobufs;
1238 }
1239
1240
1241 /*
1242  * N.B. The flags may be moved into the flowi at some future stage.
1243  */
1244 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowidn *flp, int flags)
1245 {
1246         unsigned int hash = dn_hash(flp->saddr, flp->daddr);
1247         struct dn_route *rt = NULL;
1248
1249         if (!(flags & MSG_TRYHARD)) {
1250                 rcu_read_lock_bh();
1251                 for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1252                         rt = rcu_dereference_bh(rt->dn_next)) {
1253                         if ((flp->daddr == rt->fld.daddr) &&
1254                             (flp->saddr == rt->fld.saddr) &&
1255                             (flp->flowidn_mark == rt->fld.flowidn_mark) &&
1256                             dn_is_output_route(rt) &&
1257                             (rt->fld.flowidn_oif == flp->flowidn_oif)) {
1258                                 dst_hold_and_use(&rt->dst, jiffies);
1259                                 rcu_read_unlock_bh();
1260                                 *pprt = &rt->dst;
1261                                 return 0;
1262                         }
1263                 }
1264                 rcu_read_unlock_bh();
1265         }
1266
1267         return dn_route_output_slow(pprt, flp, flags);
1268 }
1269
1270 static int dn_route_output_key(struct dst_entry **pprt, struct flowidn *flp, int flags)
1271 {
1272         int err;
1273
1274         err = __dn_route_output_key(pprt, flp, flags);
1275         if (err == 0 && flp->flowidn_proto) {
1276                 *pprt = xfrm_lookup(&init_net, *pprt,
1277                                     flowidn_to_flowi(flp), NULL, 0);
1278                 if (IS_ERR(*pprt)) {
1279                         err = PTR_ERR(*pprt);
1280                         *pprt = NULL;
1281                 }
1282         }
1283         return err;
1284 }
1285
1286 int dn_route_output_sock(struct dst_entry __rcu **pprt, struct flowidn *fl, struct sock *sk, int flags)
1287 {
1288         int err;
1289
1290         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1291         if (err == 0 && fl->flowidn_proto) {
1292                 *pprt = xfrm_lookup(&init_net, *pprt,
1293                                     flowidn_to_flowi(fl), sk, 0);
1294                 if (IS_ERR(*pprt)) {
1295                         err = PTR_ERR(*pprt);
1296                         *pprt = NULL;
1297                 }
1298         }
1299         return err;
1300 }
1301
1302 static int dn_route_input_slow(struct sk_buff *skb)
1303 {
1304         struct dn_route *rt = NULL;
1305         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1306         struct net_device *in_dev = skb->dev;
1307         struct net_device *out_dev = NULL;
1308         struct dn_dev *dn_db;
1309         struct neighbour *neigh = NULL;
1310         unsigned int hash;
1311         int flags = 0;
1312         __le16 gateway = 0;
1313         __le16 local_src = 0;
1314         struct flowidn fld = {
1315                 .daddr = cb->dst,
1316                 .saddr = cb->src,
1317                 .flowidn_scope = RT_SCOPE_UNIVERSE,
1318                 .flowidn_mark = skb->mark,
1319                 .flowidn_iif = skb->dev->ifindex,
1320         };
1321         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1322         int err = -EINVAL;
1323         int free_res = 0;
1324
1325         dev_hold(in_dev);
1326
1327         if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
1328                 goto out;
1329
1330         /* Zero source addresses are not allowed */
1331         if (fld.saddr == 0)
1332                 goto out;
1333
1334         /*
1335          * In this case we've just received a packet from a source
1336          * outside ourselves pretending to come from us. We don't
1337          * allow it any further to prevent routing loops, spoofing and
1338          * other nasties. Loopback packets already have the dst attached
1339          * so this only affects packets which have originated elsewhere.
1340          */
1341         err  = -ENOTUNIQ;
1342         if (dn_dev_islocal(in_dev, cb->src))
1343                 goto out;
1344
1345         err = dn_fib_lookup(&fld, &res);
1346         if (err) {
1347                 if (err != -ESRCH)
1348                         goto out;
1349                 /*
1350                  * Is the destination us ?
1351                  */
1352                 if (!dn_dev_islocal(in_dev, cb->dst))
1353                         goto e_inval;
1354
1355                 res.type = RTN_LOCAL;
1356         } else {
1357                 __le16 src_map = fld.saddr;
1358                 free_res = 1;
1359
1360                 out_dev = DN_FIB_RES_DEV(res);
1361                 if (out_dev == NULL) {
1362                         net_crit_ratelimited("Bug in dn_route_input_slow() No output device\n");
1363                         goto e_inval;
1364                 }
1365                 dev_hold(out_dev);
1366
1367                 if (res.r)
1368                         src_map = fld.saddr; /* no NAT support for now */
1369
1370                 gateway = DN_FIB_RES_GW(res);
1371                 if (res.type == RTN_NAT) {
1372                         fld.daddr = dn_fib_rules_map_destination(fld.daddr, &res);
1373                         dn_fib_res_put(&res);
1374                         free_res = 0;
1375                         if (dn_fib_lookup(&fld, &res))
1376                                 goto e_inval;
1377                         free_res = 1;
1378                         if (res.type != RTN_UNICAST)
1379                                 goto e_inval;
1380                         flags |= RTCF_DNAT;
1381                         gateway = fld.daddr;
1382                 }
1383                 fld.saddr = src_map;
1384         }
1385
1386         switch(res.type) {
1387         case RTN_UNICAST:
1388                 /*
1389                  * Forwarding check here, we only check for forwarding
1390                  * being turned off, if you want to only forward intra
1391                  * area, its up to you to set the routing tables up
1392                  * correctly.
1393                  */
1394                 if (dn_db->parms.forwarding == 0)
1395                         goto e_inval;
1396
1397                 if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1398                         dn_fib_select_multipath(&fld, &res);
1399
1400                 /*
1401                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1402                  * flag as a hint to set the intra-ethernet bit when
1403                  * forwarding. If we've got NAT in operation, we don't do
1404                  * this optimisation.
1405                  */
1406                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1407                         flags |= RTCF_DOREDIRECT;
1408
1409                 local_src = DN_FIB_RES_PREFSRC(res);
1410
1411         case RTN_BLACKHOLE:
1412         case RTN_UNREACHABLE:
1413                 break;
1414         case RTN_LOCAL:
1415                 flags |= RTCF_LOCAL;
1416                 fld.saddr = cb->dst;
1417                 fld.daddr = cb->src;
1418
1419                 /* Routing tables gave us a gateway */
1420                 if (gateway)
1421                         goto make_route;
1422
1423                 /* Packet was intra-ethernet, so we know its on-link */
1424                 if (cb->rt_flags & DN_RT_F_IE) {
1425                         gateway = cb->src;
1426                         goto make_route;
1427                 }
1428
1429                 /* Use the default router if there is one */
1430                 neigh = neigh_clone(dn_db->router);
1431                 if (neigh) {
1432                         gateway = ((struct dn_neigh *)neigh)->addr;
1433                         goto make_route;
1434                 }
1435
1436                 /* Close eyes and pray */
1437                 gateway = cb->src;
1438                 goto make_route;
1439         default:
1440                 goto e_inval;
1441         }
1442
1443 make_route:
1444         rt = dst_alloc(&dn_dst_ops, out_dev, 1, DST_OBSOLETE_NONE, 0);
1445         if (rt == NULL)
1446                 goto e_nobufs;
1447
1448         rt->dn_next = NULL;
1449         memset(&rt->fld, 0, sizeof(rt->fld));
1450         rt->rt_saddr      = fld.saddr;
1451         rt->rt_daddr      = fld.daddr;
1452         rt->rt_gateway    = fld.daddr;
1453         if (gateway)
1454                 rt->rt_gateway = gateway;
1455         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1456
1457         rt->rt_dst_map    = fld.daddr;
1458         rt->rt_src_map    = fld.saddr;
1459
1460         rt->fld.saddr        = cb->src;
1461         rt->fld.daddr        = cb->dst;
1462         rt->fld.flowidn_oif  = 0;
1463         rt->fld.flowidn_iif  = in_dev->ifindex;
1464         rt->fld.flowidn_mark = fld.flowidn_mark;
1465
1466         rt->n = neigh;
1467         rt->dst.lastuse = jiffies;
1468         rt->dst.output = dn_rt_bug_out;
1469         switch (res.type) {
1470         case RTN_UNICAST:
1471                 rt->dst.input = dn_forward;
1472                 break;
1473         case RTN_LOCAL:
1474                 rt->dst.output = dn_output;
1475                 rt->dst.input = dn_nsp_rx;
1476                 rt->dst.dev = in_dev;
1477                 flags |= RTCF_LOCAL;
1478                 break;
1479         default:
1480         case RTN_UNREACHABLE:
1481         case RTN_BLACKHOLE:
1482                 rt->dst.input = dst_discard;
1483         }
1484         rt->rt_flags = flags;
1485
1486         err = dn_rt_set_next_hop(rt, &res);
1487         if (err)
1488                 goto e_neighbour;
1489
1490         hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1491         /* dn_insert_route() increments dst->__refcnt */
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_release_immediate(&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->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_hold_and_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                              struct netlink_ext_ack *extack)
1637 {
1638         struct net *net = sock_net(in_skb->sk);
1639         struct rtmsg *rtm = nlmsg_data(nlh);
1640         struct dn_route *rt = NULL;
1641         struct dn_skb_cb *cb;
1642         int err;
1643         struct sk_buff *skb;
1644         struct flowidn fld;
1645         struct nlattr *tb[RTA_MAX+1];
1646
1647         if (!net_eq(net, &init_net))
1648                 return -EINVAL;
1649
1650         err = nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
1651                                      rtm_dn_policy, extack);
1652         if (err < 0)
1653                 return err;
1654
1655         memset(&fld, 0, sizeof(fld));
1656         fld.flowidn_proto = DNPROTO_NSP;
1657
1658         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1659         if (skb == NULL)
1660                 return -ENOBUFS;
1661         skb_reset_mac_header(skb);
1662         cb = DN_SKB_CB(skb);
1663
1664         if (tb[RTA_SRC])
1665                 fld.saddr = nla_get_le16(tb[RTA_SRC]);
1666
1667         if (tb[RTA_DST])
1668                 fld.daddr = nla_get_le16(tb[RTA_DST]);
1669
1670         if (tb[RTA_IIF])
1671                 fld.flowidn_iif = nla_get_u32(tb[RTA_IIF]);
1672
1673         if (fld.flowidn_iif) {
1674                 struct net_device *dev;
1675                 dev = __dev_get_by_index(&init_net, fld.flowidn_iif);
1676                 if (!dev || !dev->dn_ptr) {
1677                         kfree_skb(skb);
1678                         return -ENODEV;
1679                 }
1680                 skb->protocol = htons(ETH_P_DNA_RT);
1681                 skb->dev = dev;
1682                 cb->src = fld.saddr;
1683                 cb->dst = fld.daddr;
1684                 local_bh_disable();
1685                 err = dn_route_input(skb);
1686                 local_bh_enable();
1687                 memset(cb, 0, sizeof(struct dn_skb_cb));
1688                 rt = (struct dn_route *)skb_dst(skb);
1689                 if (!err && -rt->dst.error)
1690                         err = rt->dst.error;
1691         } else {
1692                 if (tb[RTA_OIF])
1693                         fld.flowidn_oif = nla_get_u32(tb[RTA_OIF]);
1694
1695                 err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
1696         }
1697
1698         skb->dev = NULL;
1699         if (err)
1700                 goto out_free;
1701         skb_dst_set(skb, &rt->dst);
1702         if (rtm->rtm_flags & RTM_F_NOTIFY)
1703                 rt->rt_flags |= RTCF_NOTIFY;
1704
1705         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1706         if (err < 0) {
1707                 err = -EMSGSIZE;
1708                 goto out_free;
1709         }
1710
1711         return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).portid);
1712
1713 out_free:
1714         kfree_skb(skb);
1715         return err;
1716 }
1717
1718 /*
1719  * For routers, this is called from dn_fib_dump, but for endnodes its
1720  * called directly from the rtnetlink dispatch table.
1721  */
1722 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1723 {
1724         struct net *net = sock_net(skb->sk);
1725         struct dn_route *rt;
1726         int h, s_h;
1727         int idx, s_idx;
1728         struct rtmsg *rtm;
1729
1730         if (!net_eq(net, &init_net))
1731                 return 0;
1732
1733         if (nlmsg_len(cb->nlh) < sizeof(struct rtmsg))
1734                 return -EINVAL;
1735
1736         rtm = nlmsg_data(cb->nlh);
1737         if (!(rtm->rtm_flags & RTM_F_CLONED))
1738                 return 0;
1739
1740         s_h = cb->args[0];
1741         s_idx = idx = cb->args[1];
1742         for(h = 0; h <= dn_rt_hash_mask; h++) {
1743                 if (h < s_h)
1744                         continue;
1745                 if (h > s_h)
1746                         s_idx = 0;
1747                 rcu_read_lock_bh();
1748                 for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1749                         rt;
1750                         rt = rcu_dereference_bh(rt->dn_next), idx++) {
1751                         if (idx < s_idx)
1752                                 continue;
1753                         skb_dst_set(skb, dst_clone(&rt->dst));
1754                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).portid,
1755                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1756                                         1, NLM_F_MULTI) < 0) {
1757                                 skb_dst_drop(skb);
1758                                 rcu_read_unlock_bh();
1759                                 goto done;
1760                         }
1761                         skb_dst_drop(skb);
1762                 }
1763                 rcu_read_unlock_bh();
1764         }
1765
1766 done:
1767         cb->args[0] = h;
1768         cb->args[1] = idx;
1769         return skb->len;
1770 }
1771
1772 #ifdef CONFIG_PROC_FS
1773 struct dn_rt_cache_iter_state {
1774         int bucket;
1775 };
1776
1777 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1778 {
1779         struct dn_route *rt = NULL;
1780         struct dn_rt_cache_iter_state *s = seq->private;
1781
1782         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1783                 rcu_read_lock_bh();
1784                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1785                 if (rt)
1786                         break;
1787                 rcu_read_unlock_bh();
1788         }
1789         return rt;
1790 }
1791
1792 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1793 {
1794         struct dn_rt_cache_iter_state *s = seq->private;
1795
1796         rt = rcu_dereference_bh(rt->dn_next);
1797         while (!rt) {
1798                 rcu_read_unlock_bh();
1799                 if (--s->bucket < 0)
1800                         break;
1801                 rcu_read_lock_bh();
1802                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1803         }
1804         return rt;
1805 }
1806
1807 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1808 {
1809         struct dn_route *rt = dn_rt_cache_get_first(seq);
1810
1811         if (rt) {
1812                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1813                         --*pos;
1814         }
1815         return *pos ? NULL : rt;
1816 }
1817
1818 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1819 {
1820         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1821         ++*pos;
1822         return rt;
1823 }
1824
1825 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1826 {
1827         if (v)
1828                 rcu_read_unlock_bh();
1829 }
1830
1831 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1832 {
1833         struct dn_route *rt = v;
1834         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1835
1836         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1837                    rt->dst.dev ? rt->dst.dev->name : "*",
1838                    dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1839                    dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1840                    atomic_read(&rt->dst.__refcnt),
1841                    rt->dst.__use, 0);
1842         return 0;
1843 }
1844
1845 static const struct seq_operations dn_rt_cache_seq_ops = {
1846         .start  = dn_rt_cache_seq_start,
1847         .next   = dn_rt_cache_seq_next,
1848         .stop   = dn_rt_cache_seq_stop,
1849         .show   = dn_rt_cache_seq_show,
1850 };
1851 #endif /* CONFIG_PROC_FS */
1852
1853 void __init dn_route_init(void)
1854 {
1855         int i, goal, order;
1856
1857         dn_dst_ops.kmem_cachep =
1858                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1859                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1860         dst_entries_init(&dn_dst_ops);
1861         timer_setup(&dn_route_timer, dn_dst_check_expire, 0);
1862         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1863         add_timer(&dn_route_timer);
1864
1865         goal = totalram_pages() >> (26 - PAGE_SHIFT);
1866
1867         for(order = 0; (1UL << order) < goal; order++)
1868                 /* NOTHING */;
1869
1870         /*
1871          * Only want 1024 entries max, since the table is very, very unlikely
1872          * to be larger than that.
1873          */
1874         while(order && ((((1UL << order) * PAGE_SIZE) /
1875                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1876                 order--;
1877
1878         do {
1879                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1880                         sizeof(struct dn_rt_hash_bucket);
1881                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1882                         dn_rt_hash_mask--;
1883                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1884                         __get_free_pages(GFP_ATOMIC, order);
1885         } while (dn_rt_hash_table == NULL && --order > 0);
1886
1887         if (!dn_rt_hash_table)
1888                 panic("Failed to allocate DECnet route cache hash table\n");
1889
1890         printk(KERN_INFO
1891                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1892                 dn_rt_hash_mask,
1893                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1894
1895         dn_rt_hash_mask--;
1896         for(i = 0; i <= dn_rt_hash_mask; i++) {
1897                 spin_lock_init(&dn_rt_hash_table[i].lock);
1898                 dn_rt_hash_table[i].chain = NULL;
1899         }
1900
1901         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1902
1903         proc_create_seq_private("decnet_cache", 0444, init_net.proc_net,
1904                         &dn_rt_cache_seq_ops,
1905                         sizeof(struct dn_rt_cache_iter_state), NULL);
1906
1907 #ifdef CONFIG_DECNET_ROUTER
1908         rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_GETROUTE,
1909                              dn_cache_getroute, dn_fib_dump, 0);
1910 #else
1911         rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_GETROUTE,
1912                              dn_cache_getroute, dn_cache_dump, 0);
1913 #endif
1914 }
1915
1916 void __exit dn_route_cleanup(void)
1917 {
1918         del_timer(&dn_route_timer);
1919         dn_run_flush(NULL);
1920
1921         remove_proc_entry("decnet_cache", init_net.proc_net);
1922         dst_entries_destroy(&dn_dst_ops);
1923 }