net/decnet/dn_route.c

   1 /*
   2  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   3  *              operating system.  DECnet is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              DECnet Routing Functions (Endnode and Router)
   7  *
   8  * Authors:     Steve Whitehouse <SteveW@ACM.org>
   9  *              Eduardo Marcelo Serrat <emserrat@geocities.com>
  10  *
  11  * Changes:
  12  *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
  13  *                                 "return-to-sender" bits on outgoing
  14  *                                 packets.
  15  *              Steve Whitehouse : Timeouts for cached routes.
  16  *              Steve Whitehouse : Use dst cache for input routes too.
  17  *              Steve Whitehouse : Fixed error values in dn_send_skb.
  18  *              Steve Whitehouse : Rework routing functions to better fit
  19  *                                 DECnet routing design
  20  *              Alexey Kuznetsov : New SMP locking
  21  *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
  22  *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
  23  *                                 Fixed possible skb leak in rtnetlink funcs.
  24  *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
  25  *                                 Alexey Kuznetsov's finer grained locking
  26  *                                 from ipv4/route.c.
  27  *              Steve Whitehouse : Routing is now starting to look like a
  28  *                                 sensible set of code now, mainly due to
  29  *                                 my copying the IPv4 routing code. The
  30  *                                 hooks here are modified and will continue
  31  *                                 to evolve for a while.
  32  *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
  33  *                                 stuff. Look out raw sockets your days
  34  *                                 are numbered!
  35  *              Steve Whitehouse : Added return-to-sender functions. Added
  36  *                                 backlog congestion level return codes.
  37  *              Steve Whitehouse : Fixed bug where routes were set up with
  38  *                                 no ref count on net devices.
  39  *              Steve Whitehouse : RCU for the route cache
  40  *              Steve Whitehouse : Preparations for the flow cache
  41  *              Steve Whitehouse : Prepare for nonlinear skbs
  42  */
  43
  44 /******************************************************************************
  45     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
  46
  47     This program is free software; you can redistribute it and/or modify
  48     it under the terms of the GNU General Public License as published by
  49     the Free Software Foundation; either version 2 of the License, or
  50     any later version.
  51
  52     This program is distributed in the hope that it will be useful,
  53     but WITHOUT ANY WARRANTY; without even the implied warranty of
  54     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  55     GNU General Public License for more details.
  56 *******************************************************************************/
  57
  58 #include <linux/errno.h>
  59 #include <linux/types.h>
  60 #include <linux/socket.h>
  61 #include <linux/in.h>
  62 #include <linux/kernel.h>
  63 #include <linux/sockios.h>
  64 #include <linux/net.h>
  65 #include <linux/netdevice.h>
  66 #include <linux/inet.h>
  67 #include <linux/route.h>
  68 #include <linux/in_route.h>
  69 #include <linux/slab.h>
  70 #include <net/sock.h>
  71 #include <linux/mm.h>
  72 #include <linux/proc_fs.h>
  73 #include <linux/seq_file.h>
  74 #include <linux/init.h>
  75 #include <linux/rtnetlink.h>
  76 #include <linux/string.h>
  77 #include <linux/netfilter_decnet.h>
  78 #include <linux/rcupdate.h>
  79 #include <linux/times.h>
  80 #include <linux/export.h>
  81 #include <asm/errno.h>
  82 #include <net/net_namespace.h>
  83 #include <net/netlink.h>
  84 #include <net/neighbour.h>
  85 #include <net/dst.h>
  86 #include <net/flow.h>
  87 #include <net/fib_rules.h>
  88 #include <net/dn.h>
  89 #include <net/dn_dev.h>
  90 #include <net/dn_nsp.h>
  91 #include <net/dn_route.h>
  92 #include <net/dn_neigh.h>
  93 #include <net/dn_fib.h>
  94
  95 struct dn_rt_hash_bucket
  96 {
  97         struct dn_route __rcu *chain;
  98         spinlock_t lock;
  99 };
 100
 101 extern struct neigh_table dn_neigh_table;
 102
 103
 104 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 105
 106 static const int dn_rt_min_delay = 2 * HZ;
 107 static const int dn_rt_max_delay = 10 * HZ;
 108 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 109
 110 static unsigned long dn_rt_deadline;
 111
 112 static int dn_dst_gc(struct dst_ops *ops);
 113 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 114 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst);
 115 static unsigned int dn_dst_mtu(const struct dst_entry *dst);
 116 static void dn_dst_destroy(struct dst_entry *);
 117 static void dn_dst_ifdown(struct dst_entry *, struct net_device *dev, int how);
 118 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 119 static void dn_dst_link_failure(struct sk_buff *);
 120 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
 121                                struct sk_buff *skb , u32 mtu);
 122 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
 123                             struct sk_buff *skb);
 124 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
 125                                              struct sk_buff *skb,
 126                                              const void *daddr);
 127 static int dn_route_input(struct sk_buff *);
 128 static void dn_run_flush(unsigned long dummy);
 129
 130 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 131 static unsigned int dn_rt_hash_mask;
 132
 133 static struct timer_list dn_route_timer;
 134 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 135 int decnet_dst_gc_interval = 2;
 136
 137 static struct dst_ops dn_dst_ops = {
 138         .family =               PF_DECnet,
 139         .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 inline void dnrt_free(struct dn_route *rt)
 187 {
 188         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 189 }
 190
 191 static void dn_dst_check_expire(unsigned long dummy)
 192 {
 193         int i;
 194         struct dn_route *rt;
 195         struct dn_route __rcu **rtp;
 196         unsigned long now = jiffies;
 197         unsigned long expire = 120 * HZ;
 198
 199         for (i = 0; i <= dn_rt_hash_mask; i++) {
 200                 rtp = &dn_rt_hash_table[i].chain;
 201
 202                 spin_lock(&dn_rt_hash_table[i].lock);
 203                 while ((rt = rcu_dereference_protected(*rtp,
 204                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 205                         if (atomic_read(&rt->dst.__refcnt) ||
 206                                         (now - rt->dst.lastuse) < expire) {
 207                                 rtp = &rt->dst.dn_next;
 208                                 continue;
 209                         }
 210                         *rtp = rt->dst.dn_next;
 211                         rt->dst.dn_next = NULL;
 212                         dnrt_free(rt);
 213                 }
 214                 spin_unlock(&dn_rt_hash_table[i].lock);
 215
 216                 if ((jiffies - now) > 0)
 217                         break;
 218         }
 219
 220         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 221 }
 222
 223 static int dn_dst_gc(struct dst_ops *ops)
 224 {
 225         struct dn_route *rt;
 226         struct dn_route __rcu **rtp;
 227         int i;
 228         unsigned long now = jiffies;
 229         unsigned long expire = 10 * HZ;
 230
 231         for (i = 0; i <= dn_rt_hash_mask; i++) {
 232
 233                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 234                 rtp = &dn_rt_hash_table[i].chain;
 235
 236                 while ((rt = rcu_dereference_protected(*rtp,
 237                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 238                         if (atomic_read(&rt->dst.__refcnt) ||
 239                                         (now - rt->dst.lastuse) < expire) {
 240                                 rtp = &rt->dst.dn_next;
 241                                 continue;
 242                         }
 243                         *rtp = rt->dst.dn_next;
 244                         rt->dst.dn_next = NULL;
 245                         dnrt_free(rt);
 246                         break;
 247                 }
 248                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 249         }
 250
 251         return 0;
 252 }
 253
 254 /*
 255  * The decnet standards don't impose a particular minimum mtu, what they
 256  * do insist on is that the routing layer accepts a datagram of at least
 257  * 230 bytes long. Here we have to subtract the routing header length from
 258  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 259  * assume the worst and use a long header size.
 260  *
 261  * We update both the mtu and the advertised mss (i.e. the segment size we
 262  * advertise to the other end).
 263  */
 264 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
 265                                struct sk_buff *skb, u32 mtu)
 266 {
 267         struct dn_route *rt = (struct dn_route *) dst;
 268         struct neighbour *n = rt->n;
 269         u32 min_mtu = 230;
 270         struct dn_dev *dn;
 271
 272         dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL;
 273
 274         if (dn && dn->use_long == 0)
 275                 min_mtu -= 6;
 276         else
 277                 min_mtu -= 21;
 278
 279         if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
 280                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
 281                         dst_metric_set(dst, RTAX_MTU, mtu);
 282                         dst_set_expires(dst, dn_rt_mtu_expires);
 283                 }
 284                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 285                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 286                         u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
 287                         if (!existing_mss || existing_mss > mss)
 288                                 dst_metric_set(dst, RTAX_ADVMSS, mss);
 289                 }
 290         }
 291 }
 292
 293 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
 294                             struct sk_buff *skb)
 295 {
 296 }
 297
 298 /*
 299  * When a route has been marked obsolete. (e.g. routing cache flush)
 300  */
 301 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 302 {
 303         return NULL;
 304 }
 305
 306 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 307 {
 308         dst_release(dst);
 309         return NULL;
 310 }
 311
 312 static void dn_dst_link_failure(struct sk_buff *skb)
 313 {
 314 }
 315
 316 static inline int compare_keys(struct flowidn *fl1, struct flowidn *fl2)
 317 {
 318         return ((fl1->daddr ^ fl2->daddr) |
 319                 (fl1->saddr ^ fl2->saddr) |
 320                 (fl1->flowidn_mark ^ fl2->flowidn_mark) |
 321                 (fl1->flowidn_scope ^ fl2->flowidn_scope) |
 322                 (fl1->flowidn_oif ^ fl2->flowidn_oif) |
 323                 (fl1->flowidn_iif ^ fl2->flowidn_iif)) == 0;
 324 }
 325
 326 static int dn_insert_route(struct dn_route *rt, unsigned int hash, struct dn_route **rp)
 327 {
 328         struct dn_route *rth;
 329         struct dn_route __rcu **rthp;
 330         unsigned long now = jiffies;
 331
 332         rthp = &dn_rt_hash_table[hash].chain;
 333
 334         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 335         while ((rth = rcu_dereference_protected(*rthp,
 336                                                 lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
 337                 if (compare_keys(&rth->fld, &rt->fld)) {
 338                         /* Put it first */
 339                         *rthp = rth->dst.dn_next;
 340                         rcu_assign_pointer(rth->dst.dn_next,
 341                                            dn_rt_hash_table[hash].chain);
 342                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 343
 344                         dst_use(&rth->dst, now);
 345                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 346
 347                         dst_free(&rt->dst);
 348                         *rp = rth;
 349                         return 0;
 350                 }
 351                 rthp = &rth->dst.dn_next;
 352         }
 353
 354         rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain);
 355         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 356
 357         dst_use(&rt->dst, now);
 358         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 359         *rp = rt;
 360         return 0;
 361 }
 362
 363 static void dn_run_flush(unsigned long dummy)
 364 {
 365         int i;
 366         struct dn_route *rt, *next;
 367
 368         for (i = 0; i < dn_rt_hash_mask; i++) {
 369                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 370
 371                 if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
 372                         goto nothing_to_declare;
 373
 374                 for(; rt; rt = next) {
 375                         next = rcu_dereference_raw(rt->dst.dn_next);
 376                         RCU_INIT_POINTER(rt->dst.dn_next, NULL);
 377                         dnrt_free(rt);
 378                 }
 379
 380 nothing_to_declare:
 381                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 382         }
 383 }
 384
 385 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 386
 387 void dn_rt_cache_flush(int delay)
 388 {
 389         unsigned long now = jiffies;
 390         int user_mode = !in_interrupt();
 391
 392         if (delay < 0)
 393                 delay = dn_rt_min_delay;
 394
 395         spin_lock_bh(&dn_rt_flush_lock);
 396
 397         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 398                 long tmo = (long)(dn_rt_deadline - now);
 399
 400                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 401                         tmo = 0;
 402
 403                 if (delay > tmo)
 404                         delay = tmo;
 405         }
 406
 407         if (delay <= 0) {
 408                 spin_unlock_bh(&dn_rt_flush_lock);
 409                 dn_run_flush(0);
 410                 return;
 411         }
 412
 413         if (dn_rt_deadline == 0)
 414                 dn_rt_deadline = now + dn_rt_max_delay;
 415
 416         dn_rt_flush_timer.expires = now + delay;
 417         add_timer(&dn_rt_flush_timer);
 418         spin_unlock_bh(&dn_rt_flush_lock);
 419 }
 420
 421 /**
 422  * dn_return_short - Return a short packet to its sender
 423  * @skb: The packet to return
 424  *
 425  */
 426 static int dn_return_short(struct sk_buff *skb)
 427 {
 428         struct dn_skb_cb *cb;
 429         unsigned char *ptr;
 430         __le16 *src;
 431         __le16 *dst;
 432
 433         /* Add back headers */
 434         skb_push(skb, skb->data - skb_network_header(skb));
 435
 436         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 437                 return NET_RX_DROP;
 438
 439         cb = DN_SKB_CB(skb);
 440         /* Skip packet length and point to flags */
 441         ptr = skb->data + 2;
 442         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 443
 444         dst = (__le16 *)ptr;
 445         ptr += 2;
 446         src = (__le16 *)ptr;
 447         ptr += 2;
 448         *ptr = 0; /* Zero hop count */
 449
 450         swap(*src, *dst);
 451
 452         skb->pkt_type = PACKET_OUTGOING;
 453         dn_rt_finish_output(skb, NULL, NULL);
 454         return NET_RX_SUCCESS;
 455 }
 456
 457 /**
 458  * dn_return_long - Return a long packet to its sender
 459  * @skb: The long format packet to return
 460  *
 461  */
 462 static int dn_return_long(struct sk_buff *skb)
 463 {
 464         struct dn_skb_cb *cb;
 465         unsigned char *ptr;
 466         unsigned char *src_addr, *dst_addr;
 467         unsigned char tmp[ETH_ALEN];
 468
 469         /* Add back all headers */
 470         skb_push(skb, skb->data - skb_network_header(skb));
 471
 472         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 473                 return NET_RX_DROP;
 474
 475         cb = DN_SKB_CB(skb);
 476         /* Ignore packet length and point to flags */
 477         ptr = skb->data + 2;
 478
 479         /* Skip padding */
 480         if (*ptr & DN_RT_F_PF) {
 481                 char padlen = (*ptr & ~DN_RT_F_PF);
 482                 ptr += padlen;
 483         }
 484
 485         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 486         ptr += 2;
 487         dst_addr = ptr;
 488         ptr += 8;
 489         src_addr = ptr;
 490         ptr += 6;
 491         *ptr = 0; /* Zero hop count */
 492
 493         /* Swap source and destination */
 494         memcpy(tmp, src_addr, ETH_ALEN);
 495         memcpy(src_addr, dst_addr, ETH_ALEN);
 496         memcpy(dst_addr, tmp, ETH_ALEN);
 497
 498         skb->pkt_type = PACKET_OUTGOING;
 499         dn_rt_finish_output(skb, dst_addr, src_addr);
 500         return NET_RX_SUCCESS;
 501 }
 502
 503 /**
 504  * dn_route_rx_packet - Try and find a route for an incoming packet
 505  * @skb: The packet to find a route for
 506  *
 507  * Returns: result of input function if route is found, error code otherwise
 508  */
 509 static int dn_route_rx_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
 510 {
 511         struct dn_skb_cb *cb;
 512         int err;
 513
 514         if ((err = dn_route_input(skb)) == 0)
 515                 return dst_input(skb);
 516
 517         cb = DN_SKB_CB(skb);
 518         if (decnet_debug_level & 4) {
 519                 char *devname = skb->dev ? skb->dev->name : "???";
 520
 521                 printk(KERN_DEBUG
 522                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 523                         (int)cb->rt_flags, devname, skb->len,
 524                         le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
 525                         err, skb->pkt_type);
 526         }
 527
 528         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 529                 switch (cb->rt_flags & DN_RT_PKT_MSK) {
 530                 case DN_RT_PKT_SHORT:
 531                         return dn_return_short(skb);
 532                 case DN_RT_PKT_LONG:
 533                         return dn_return_long(skb);
 534                 }
 535         }
 536
 537         kfree_skb(skb);
 538         return NET_RX_DROP;
 539 }
 540
 541 static int dn_route_rx_long(struct sk_buff *skb)
 542 {
 543         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 544         unsigned char *ptr = skb->data;
 545
 546         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 547                 goto drop_it;
 548
 549         skb_pull(skb, 20);
 550         skb_reset_transport_header(skb);
 551
 552         /* Destination info */
 553         ptr += 2;
 554         cb->dst = dn_eth2dn(ptr);
 555         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 556                 goto drop_it;
 557         ptr += 6;
 558
 559
 560         /* Source info */
 561         ptr += 2;
 562         cb->src = dn_eth2dn(ptr);
 563         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 564                 goto drop_it;
 565         ptr += 6;
 566         /* Other junk */
 567         ptr++;
 568         cb->hops = *ptr++; /* Visit Count */
 569
 570         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
 571                        &init_net, NULL, skb, skb->dev, NULL,
 572                        dn_route_rx_packet);
 573
 574 drop_it:
 575         kfree_skb(skb);
 576         return NET_RX_DROP;
 577 }
 578
 579
 580
 581 static int dn_route_rx_short(struct sk_buff *skb)
 582 {
 583         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 584         unsigned char *ptr = skb->data;
 585
 586         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 587                 goto drop_it;
 588
 589         skb_pull(skb, 5);
 590         skb_reset_transport_header(skb);
 591
 592         cb->dst = *(__le16 *)ptr;
 593         ptr += 2;
 594         cb->src = *(__le16 *)ptr;
 595         ptr += 2;
 596         cb->hops = *ptr & 0x3f;
 597
 598         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
 599                        &init_net, NULL, skb, skb->dev, NULL,
 600                        dn_route_rx_packet);
 601
 602 drop_it:
 603         kfree_skb(skb);
 604         return NET_RX_DROP;
 605 }
 606
 607 static int dn_route_discard(struct net *net, struct sock *sk, struct sk_buff *skb)
 608 {
 609         /*
 610          * I know we drop the packet here, but thats considered success in
 611          * this case
 612          */
 613         kfree_skb(skb);
 614         return NET_RX_SUCCESS;
 615 }
 616
 617 static int dn_route_ptp_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
 618 {
 619         dn_dev_hello(skb);
 620         dn_neigh_pointopoint_hello(skb);
 621         return NET_RX_SUCCESS;
 622 }
 623
 624 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 625 {
 626         struct dn_skb_cb *cb;
 627         unsigned char flags = 0;
 628         __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 629         struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
 630         unsigned char padlen = 0;
 631
 632         if (!net_eq(dev_net(dev), &init_net))
 633                 goto dump_it;
 634
 635         if (dn == NULL)
 636                 goto dump_it;
 637
 638         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 639                 goto out;
 640
 641         if (!pskb_may_pull(skb, 3))
 642                 goto dump_it;
 643
 644         skb_pull(skb, 2);
 645
 646         if (len > skb->len)
 647                 goto dump_it;
 648
 649         skb_trim(skb, len);
 650
 651         flags = *skb->data;
 652
 653         cb = DN_SKB_CB(skb);
 654         cb->stamp = jiffies;
 655         cb->iif = dev->ifindex;
 656
 657         /*
 658          * If we have padding, remove it.
 659          */
 660         if (flags & DN_RT_F_PF) {
 661                 padlen = flags & ~DN_RT_F_PF;
 662                 if (!pskb_may_pull(skb, padlen + 1))
 663                         goto dump_it;
 664                 skb_pull(skb, padlen);
 665                 flags = *skb->data;
 666         }
 667
 668         skb_reset_network_header(skb);
 669
 670         /*
 671          * Weed out future version DECnet
 672          */
 673         if (flags & DN_RT_F_VER)
 674                 goto dump_it;
 675
 676         cb->rt_flags = flags;
 677
 678         if (decnet_debug_level & 1)
 679                 printk(KERN_DEBUG
 680                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 681                         (int)flags, (dev) ? dev->name : "???", len, skb->len,
 682                         padlen);
 683
 684         if (flags & DN_RT_PKT_CNTL) {
 685                 if (unlikely(skb_linearize(skb)))
 686                         goto dump_it;
 687
 688                 switch (flags & DN_RT_CNTL_MSK) {
 689                 case DN_RT_PKT_INIT:
 690                         dn_dev_init_pkt(skb);
 691                         break;
 692                 case DN_RT_PKT_VERI:
 693                         dn_dev_veri_pkt(skb);
 694                         break;
 695                 }
 696
 697                 if (dn->parms.state != DN_DEV_S_RU)
 698                         goto dump_it;
 699
 700                 switch (flags & DN_RT_CNTL_MSK) {
 701                 case DN_RT_PKT_HELO:
 702                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 703                                        &init_net, NULL, skb, skb->dev, NULL,
 704                                        dn_route_ptp_hello);
 705
 706                 case DN_RT_PKT_L1RT:
 707                 case DN_RT_PKT_L2RT:
 708                         return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
 709                                        &init_net, NULL, skb, skb->dev, NULL,
 710                                        dn_route_discard);
 711                 case DN_RT_PKT_ERTH:
 712                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 713                                        &init_net, NULL, skb, skb->dev, NULL,
 714                                        dn_neigh_router_hello);
 715
 716                 case DN_RT_PKT_EEDH:
 717                         return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 718                                        &init_net, NULL, skb, skb->dev, NULL,
 719                                        dn_neigh_endnode_hello);
 720                 }
 721         } else {
 722                 if (dn->parms.state != DN_DEV_S_RU)
 723                         goto dump_it;
 724
 725                 skb_pull(skb, 1); /* Pull flags */
 726
 727                 switch (flags & DN_RT_PKT_MSK) {
 728                 case DN_RT_PKT_LONG:
 729                         return dn_route_rx_long(skb);
 730                 case DN_RT_PKT_SHORT:
 731                         return dn_route_rx_short(skb);
 732                 }
 733         }
 734
 735 dump_it:
 736         kfree_skb(skb);
 737 out:
 738         return NET_RX_DROP;
 739 }
 740
 741 static int dn_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 742 {
 743         struct dst_entry *dst = skb_dst(skb);
 744         struct dn_route *rt = (struct dn_route *)dst;
 745         struct net_device *dev = dst->dev;
 746         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 747
 748         int err = -EINVAL;
 749
 750         if (rt->n == NULL)
 751                 goto error;
 752
 753         skb->dev = dev;
 754
 755         cb->src = rt->rt_saddr;
 756         cb->dst = rt->rt_daddr;
 757
 758         /*
 759          * Always set the Intra-Ethernet bit on all outgoing packets
 760          * originated on this node. Only valid flag from upper layers
 761          * is return-to-sender-requested. Set hop count to 0 too.
 762          */
 763         cb->rt_flags &= ~DN_RT_F_RQR;
 764         cb->rt_flags |= DN_RT_F_IE;
 765         cb->hops = 0;
 766
 767         return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT,
 768                        &init_net, sk, skb, NULL, dev,
 769                        dn_to_neigh_output);
 770
 771 error:
 772         net_dbg_ratelimited("dn_output: This should not happen\n");
 773
 774         kfree_skb(skb);
 775
 776         return err;
 777 }
 778
 779 static int dn_forward(struct sk_buff *skb)
 780 {
 781         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 782         struct dst_entry *dst = skb_dst(skb);
 783         struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
 784         struct dn_route *rt;
 785         int header_len;
 786         struct net_device *dev = skb->dev;
 787
 788         if (skb->pkt_type != PACKET_HOST)
 789                 goto drop;
 790
 791         /* Ensure that we have enough space for headers */
 792         rt = (struct dn_route *)skb_dst(skb);
 793         header_len = dn_db->use_long ? 21 : 6;
 794         if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
 795                 goto drop;
 796
 797         /*
 798          * Hop count exceeded.
 799          */
 800         if (++cb->hops > 30)
 801                 goto drop;
 802
 803         skb->dev = rt->dst.dev;
 804
 805         /*
 806          * If packet goes out same interface it came in on, then set
 807          * the Intra-Ethernet bit. This has no effect for short
 808          * packets, so we don't need to test for them here.
 809          */
 810         cb->rt_flags &= ~DN_RT_F_IE;
 811         if (rt->rt_flags & RTCF_DOREDIRECT)
 812                 cb->rt_flags |= DN_RT_F_IE;
 813
 814         return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD,
 815                        &init_net, NULL, skb, dev, skb->dev,
 816                        dn_to_neigh_output);
 817
 818 drop:
 819         kfree_skb(skb);
 820         return NET_RX_DROP;
 821 }
 822
 823 /*
 824  * Used to catch bugs. This should never normally get
 825  * called.
 826  */
 827 static int dn_rt_bug_out(struct net *net, struct sock *sk, struct sk_buff *skb)
 828 {
 829         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 830
 831         net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
 832                             le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 833
 834         kfree_skb(skb);
 835
 836         return NET_RX_DROP;
 837 }
 838
 839 static int dn_rt_bug(struct sk_buff *skb)
 840 {
 841         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 842
 843         net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
 844                             le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 845
 846         kfree_skb(skb);
 847
 848         return NET_RX_DROP;
 849 }
 850
 851 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
 852 {
 853         return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
 854 }
 855
 856 static unsigned int dn_dst_mtu(const struct dst_entry *dst)
 857 {
 858         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
 859
 860         return mtu ? : dst->dev->mtu;
 861 }
 862
 863 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
 864                                              struct sk_buff *skb,
 865                                              const void *daddr)
 866 {
 867         return __neigh_lookup_errno(&dn_neigh_table, daddr, dst->dev);
 868 }
 869
 870 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 871 {
 872         struct dn_fib_info *fi = res->fi;
 873         struct net_device *dev = rt->dst.dev;
 874         unsigned int mss_metric;
 875         struct neighbour *n;
 876
 877         if (fi) {
 878                 if (DN_FIB_RES_GW(*res) &&
 879                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 880                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 881                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
 882         }
 883         rt->rt_type = res->type;
 884
 885         if (dev != NULL && rt->n == NULL) {
 886                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 887                 if (IS_ERR(n))
 888                         return PTR_ERR(n);
 889                 rt->n = n;
 890         }
 891
 892         if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
 893                 dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
 894         mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
 895         if (mss_metric) {
 896                 unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
 897                 if (mss_metric > mss)
 898                         dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
 899         }
 900         return 0;
 901 }
 902
 903 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 904 {
 905         __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 906         int match = 16;
 907         while(tmp) {
 908                 tmp >>= 1;
 909                 match--;
 910         }
 911         return match;
 912 }
 913
 914 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 915 {
 916         __le16 saddr = 0;
 917         struct dn_dev *dn_db;
 918         struct dn_ifaddr *ifa;
 919         int best_match = 0;
 920         int ret;
 921
 922         rcu_read_lock();
 923         dn_db = rcu_dereference(dev->dn_ptr);
 924         for (ifa = rcu_dereference(dn_db->ifa_list);
 925              ifa != NULL;
 926              ifa = rcu_dereference(ifa->ifa_next)) {
 927                 if (ifa->ifa_scope > scope)
 928                         continue;
 929                 if (!daddr) {
 930                         saddr = ifa->ifa_local;
 931                         break;
 932                 }
 933                 ret = dn_match_addr(daddr, ifa->ifa_local);
 934                 if (ret > best_match)
 935                         saddr = ifa->ifa_local;
 936                 if (best_match == 0)
 937                         saddr = ifa->ifa_local;
 938         }
 939         rcu_read_unlock();
 940
 941         return saddr;
 942 }
 943
 944 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 945 {
 946         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 947 }
 948
 949 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 950 {
 951         __le16 mask = dnet_make_mask(res->prefixlen);
 952         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 953 }
 954
 955 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowidn *oldflp, int try_hard)
 956 {
 957         struct flowidn fld = {
 958                 .daddr = oldflp->daddr,
 959                 .saddr = oldflp->saddr,
 960                 .flowidn_scope = RT_SCOPE_UNIVERSE,
 961                 .flowidn_mark = oldflp->flowidn_mark,
 962                 .flowidn_iif = LOOPBACK_IFINDEX,
 963                 .flowidn_oif = oldflp->flowidn_oif,
 964         };
 965         struct dn_route *rt = NULL;
 966         struct net_device *dev_out = NULL, *dev;
 967         struct neighbour *neigh = NULL;
 968         unsigned int hash;
 969         unsigned int flags = 0;
 970         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 971         int err;
 972         int free_res = 0;
 973         __le16 gateway = 0;
 974
 975         if (decnet_debug_level & 16)
 976                 printk(KERN_DEBUG
 977                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 978                        " iif=%d oif=%d\n", le16_to_cpu(oldflp->daddr),
 979                        le16_to_cpu(oldflp->saddr),
 980                        oldflp->flowidn_mark, LOOPBACK_IFINDEX,
 981                        oldflp->flowidn_oif);
 982
 983         /* If we have an output interface, verify its a DECnet device */
 984         if (oldflp->flowidn_oif) {
 985                 dev_out = dev_get_by_index(&init_net, oldflp->flowidn_oif);
 986                 err = -ENODEV;
 987                 if (dev_out && dev_out->dn_ptr == NULL) {
 988                         dev_put(dev_out);
 989                         dev_out = NULL;
 990                 }
 991                 if (dev_out == NULL)
 992                         goto out;
 993         }
 994
 995         /* If we have a source address, verify that its a local address */
 996         if (oldflp->saddr) {
 997                 err = -EADDRNOTAVAIL;
 998
 999                 if (dev_out) {
1000                         if (dn_dev_islocal(dev_out, oldflp->saddr))
1001                                 goto source_ok;
1002                         dev_put(dev_out);
1003                         goto out;
1004                 }
1005                 rcu_read_lock();
1006                 for_each_netdev_rcu(&init_net, dev) {
1007                         if (!dev->dn_ptr)
1008                                 continue;
1009                         if (!dn_dev_islocal(dev, oldflp->saddr))
1010                                 continue;
1011                         if ((dev->flags & IFF_LOOPBACK) &&
1012                             oldflp->daddr &&
1013                             !dn_dev_islocal(dev, oldflp->daddr))
1014                                 continue;
1015
1016                         dev_out = dev;
1017                         break;
1018                 }
1019                 rcu_read_unlock();
1020                 if (dev_out == NULL)
1021                         goto out;
1022                 dev_hold(dev_out);
1023 source_ok:
1024                 ;
1025         }
1026
1027         /* No destination? Assume its local */
1028         if (!fld.daddr) {
1029                 fld.daddr = fld.saddr;
1030
1031                 if (dev_out)
1032                         dev_put(dev_out);
1033                 err = -EINVAL;
1034                 dev_out = init_net.loopback_dev;
1035                 if (!dev_out->dn_ptr)
1036                         goto out;
1037                 err = -EADDRNOTAVAIL;
1038                 dev_hold(dev_out);
1039                 if (!fld.daddr) {
1040                         fld.daddr =
1041                         fld.saddr = dnet_select_source(dev_out, 0,
1042                                                        RT_SCOPE_HOST);
1043                         if (!fld.daddr)
1044                                 goto out;
1045                 }
1046                 fld.flowidn_oif = LOOPBACK_IFINDEX;
1047                 res.type = RTN_LOCAL;
1048                 goto make_route;
1049         }
1050
1051         if (decnet_debug_level & 16)
1052                 printk(KERN_DEBUG
1053                        "dn_route_output_slow: initial checks complete."
1054                        " dst=%04x src=%04x oif=%d try_hard=%d\n",
1055                        le16_to_cpu(fld.daddr), le16_to_cpu(fld.saddr),
1056                        fld.flowidn_oif, try_hard);
1057
1058         /*
1059          * N.B. If the kernel is compiled without router support then
1060          * dn_fib_lookup() will evaluate to non-zero so this if () block
1061          * will always be executed.
1062          */
1063         err = -ESRCH;
1064         if (try_hard || (err = dn_fib_lookup(&fld, &res)) != 0) {
1065                 struct dn_dev *dn_db;
1066                 if (err != -ESRCH)
1067                         goto out;
1068                 /*
1069                  * Here the fallback is basically the standard algorithm for
1070                  * routing in endnodes which is described in the DECnet routing
1071                  * docs
1072                  *
1073                  * If we are not trying hard, look in neighbour cache.
1074                  * The result is tested to ensure that if a specific output
1075                  * device/source address was requested, then we honour that
1076                  * here
1077                  */
1078                 if (!try_hard) {
1079                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fld.daddr);
1080                         if (neigh) {
1081                                 if ((oldflp->flowidn_oif &&
1082                                     (neigh->dev->ifindex != oldflp->flowidn_oif)) ||
1083                                     (oldflp->saddr &&
1084                                     (!dn_dev_islocal(neigh->dev,
1085                                                      oldflp->saddr)))) {
1086                                         neigh_release(neigh);
1087                                         neigh = NULL;
1088                                 } else {
1089                                         if (dev_out)
1090                                                 dev_put(dev_out);
1091                                         if (dn_dev_islocal(neigh->dev, fld.daddr)) {
1092                                                 dev_out = init_net.loopback_dev;
1093                                                 res.type = RTN_LOCAL;
1094                                         } else {
1095                                                 dev_out = neigh->dev;
1096                                         }
1097                                         dev_hold(dev_out);
1098                                         goto select_source;
1099                                 }
1100                         }
1101                 }
1102
1103                 /* Not there? Perhaps its a local address */
1104                 if (dev_out == NULL)
1105                         dev_out = dn_dev_get_default();
1106                 err = -ENODEV;
1107                 if (dev_out == NULL)
1108                         goto out;
1109                 dn_db = rcu_dereference_raw(dev_out->dn_ptr);
1110                 if (!dn_db)
1111                         goto e_inval;
1112                 /* Possible improvement - check all devices for local addr */
1113                 if (dn_dev_islocal(dev_out, fld.daddr)) {
1114                         dev_put(dev_out);
1115                         dev_out = init_net.loopback_dev;
1116                         dev_hold(dev_out);
1117                         res.type = RTN_LOCAL;
1118                         goto select_source;
1119                 }
1120                 /* Not local either.... try sending it to the default router */
1121                 neigh = neigh_clone(dn_db->router);
1122                 BUG_ON(neigh && neigh->dev != dev_out);
1123
1124                 /* Ok then, we assume its directly connected and move on */
1125 select_source:
1126                 if (neigh)
1127                         gateway = ((struct dn_neigh *)neigh)->addr;
1128                 if (gateway == 0)
1129                         gateway = fld.daddr;
1130                 if (fld.saddr == 0) {
1131                         fld.saddr = dnet_select_source(dev_out, gateway,
1132                                                        res.type == RTN_LOCAL ?
1133                                                        RT_SCOPE_HOST :
1134                                                        RT_SCOPE_LINK);
1135                         if (fld.saddr == 0 && res.type != RTN_LOCAL)
1136                                 goto e_addr;
1137                 }
1138                 fld.flowidn_oif = dev_out->ifindex;
1139                 goto make_route;
1140         }
1141         free_res = 1;
1142
1143         if (res.type == RTN_NAT)
1144                 goto e_inval;
1145
1146         if (res.type == RTN_LOCAL) {
1147                 if (!fld.saddr)
1148                         fld.saddr = fld.daddr;
1149                 if (dev_out)
1150                         dev_put(dev_out);
1151                 dev_out = init_net.loopback_dev;
1152                 dev_hold(dev_out);
1153                 if (!dev_out->dn_ptr)
1154                         goto e_inval;
1155                 fld.flowidn_oif = dev_out->ifindex;
1156                 if (res.fi)
1157                         dn_fib_info_put(res.fi);
1158                 res.fi = NULL;
1159                 goto make_route;
1160         }
1161
1162         if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1163                 dn_fib_select_multipath(&fld, &res);
1164
1165         /*
1166          * We could add some logic to deal with default routes here and
1167          * get rid of some of the special casing above.
1168          */
1169
1170         if (!fld.saddr)
1171                 fld.saddr = DN_FIB_RES_PREFSRC(res);
1172
1173         if (dev_out)
1174                 dev_put(dev_out);
1175         dev_out = DN_FIB_RES_DEV(res);
1176         dev_hold(dev_out);
1177         fld.flowidn_oif = dev_out->ifindex;
1178         gateway = DN_FIB_RES_GW(res);
1179
1180 make_route:
1181         if (dev_out->flags & IFF_LOOPBACK)
1182                 flags |= RTCF_LOCAL;
1183
1184         rt = dst_alloc(&dn_dst_ops, dev_out, 0, DST_OBSOLETE_NONE, DST_HOST);
1185         if (rt == NULL)
1186                 goto e_nobufs;
1187
1188         memset(&rt->fld, 0, sizeof(rt->fld));
1189         rt->fld.saddr        = oldflp->saddr;
1190         rt->fld.daddr        = oldflp->daddr;
1191         rt->fld.flowidn_oif  = oldflp->flowidn_oif;
1192         rt->fld.flowidn_iif  = 0;
1193         rt->fld.flowidn_mark = oldflp->flowidn_mark;
1194
1195         rt->rt_saddr      = fld.saddr;
1196         rt->rt_daddr      = fld.daddr;
1197         rt->rt_gateway    = gateway ? gateway : fld.daddr;
1198         rt->rt_local_src  = fld.saddr;
1199
1200         rt->rt_dst_map    = fld.daddr;
1201         rt->rt_src_map    = fld.saddr;
1202
1203         rt->n = neigh;
1204         neigh = NULL;
1205
1206         rt->dst.lastuse = jiffies;
1207         rt->dst.output  = dn_output;
1208         rt->dst.input   = dn_rt_bug;
1209         rt->rt_flags      = flags;
1210         if (flags & RTCF_LOCAL)
1211                 rt->dst.input = dn_nsp_rx;
1212
1213         err = dn_rt_set_next_hop(rt, &res);
1214         if (err)
1215                 goto e_neighbour;
1216
1217         hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
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_free(&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->dst.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_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, 0, DST_OBSOLETE_NONE, DST_HOST);
1449         if (rt == NULL)
1450                 goto e_nobufs;
1451
1452         memset(&rt->fld, 0, sizeof(rt->fld));
1453         rt->rt_saddr      = fld.saddr;
1454         rt->rt_daddr      = fld.daddr;
1455         rt->rt_gateway    = fld.daddr;
1456         if (gateway)
1457                 rt->rt_gateway = gateway;
1458         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1459
1460         rt->rt_dst_map    = fld.daddr;
1461         rt->rt_src_map    = fld.saddr;
1462
1463         rt->fld.saddr        = cb->src;
1464         rt->fld.daddr        = cb->dst;
1465         rt->fld.flowidn_oif  = 0;
1466         rt->fld.flowidn_iif  = in_dev->ifindex;
1467         rt->fld.flowidn_mark = fld.flowidn_mark;
1468
1469         rt->n = neigh;
1470         rt->dst.lastuse = jiffies;
1471         rt->dst.output = dn_rt_bug_out;
1472         switch (res.type) {
1473         case RTN_UNICAST:
1474                 rt->dst.input = dn_forward;
1475                 break;
1476         case RTN_LOCAL:
1477                 rt->dst.output = dn_output;
1478                 rt->dst.input = dn_nsp_rx;
1479                 rt->dst.dev = in_dev;
1480                 flags |= RTCF_LOCAL;
1481                 break;
1482         default:
1483         case RTN_UNREACHABLE:
1484         case RTN_BLACKHOLE:
1485                 rt->dst.input = dst_discard;
1486         }
1487         rt->rt_flags = flags;
1488
1489         err = dn_rt_set_next_hop(rt, &res);
1490         if (err)
1491                 goto e_neighbour;
1492
1493         hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1494         dn_insert_route(rt, hash, &rt);
1495         skb_dst_set(skb, &rt->dst);
1496
1497 done:
1498         if (neigh)
1499                 neigh_release(neigh);
1500         if (free_res)
1501                 dn_fib_res_put(&res);
1502         dev_put(in_dev);
1503         if (out_dev)
1504                 dev_put(out_dev);
1505 out:
1506         return err;
1507
1508 e_inval:
1509         err = -EINVAL;
1510         goto done;
1511
1512 e_nobufs:
1513         err = -ENOBUFS;
1514         goto done;
1515
1516 e_neighbour:
1517         dst_free(&rt->dst);
1518         goto done;
1519 }
1520
1521 static int dn_route_input(struct sk_buff *skb)
1522 {
1523         struct dn_route *rt;
1524         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1525         unsigned int hash = dn_hash(cb->src, cb->dst);
1526
1527         if (skb_dst(skb))
1528                 return 0;
1529
1530         rcu_read_lock();
1531         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1532             rt = rcu_dereference(rt->dst.dn_next)) {
1533                 if ((rt->fld.saddr == cb->src) &&
1534                     (rt->fld.daddr == cb->dst) &&
1535                     (rt->fld.flowidn_oif == 0) &&
1536                     (rt->fld.flowidn_mark == skb->mark) &&
1537                     (rt->fld.flowidn_iif == cb->iif)) {
1538                         dst_use(&rt->dst, jiffies);
1539                         rcu_read_unlock();
1540                         skb_dst_set(skb, (struct dst_entry *)rt);
1541                         return 0;
1542                 }
1543         }
1544         rcu_read_unlock();
1545
1546         return dn_route_input_slow(skb);
1547 }
1548
1549 static int dn_rt_fill_info(struct sk_buff *skb, u32 portid, u32 seq,
1550                            int event, int nowait, unsigned int flags)
1551 {
1552         struct dn_route *rt = (struct dn_route *)skb_dst(skb);
1553         struct rtmsg *r;
1554         struct nlmsghdr *nlh;
1555         long expires;
1556
1557         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
1558         if (!nlh)
1559                 return -EMSGSIZE;
1560
1561         r = nlmsg_data(nlh);
1562         r->rtm_family = AF_DECnet;
1563         r->rtm_dst_len = 16;
1564         r->rtm_src_len = 0;
1565         r->rtm_tos = 0;
1566         r->rtm_table = RT_TABLE_MAIN;
1567         r->rtm_type = rt->rt_type;
1568         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1569         r->rtm_scope = RT_SCOPE_UNIVERSE;
1570         r->rtm_protocol = RTPROT_UNSPEC;
1571
1572         if (rt->rt_flags & RTCF_NOTIFY)
1573                 r->rtm_flags |= RTM_F_NOTIFY;
1574
1575         if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN) < 0 ||
1576             nla_put_le16(skb, RTA_DST, rt->rt_daddr) < 0)
1577                 goto errout;
1578
1579         if (rt->fld.saddr) {
1580                 r->rtm_src_len = 16;
1581                 if (nla_put_le16(skb, RTA_SRC, rt->fld.saddr) < 0)
1582                         goto errout;
1583         }
1584         if (rt->dst.dev &&
1585             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex) < 0)
1586                 goto errout;
1587
1588         /*
1589          * Note to self - change this if input routes reverse direction when
1590          * they deal only with inputs and not with replies like they do
1591          * currently.
1592          */
1593         if (nla_put_le16(skb, RTA_PREFSRC, rt->rt_local_src) < 0)
1594                 goto errout;
1595
1596         if (rt->rt_daddr != rt->rt_gateway &&
1597             nla_put_le16(skb, RTA_GATEWAY, rt->rt_gateway) < 0)
1598                 goto errout;
1599
1600         if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
1601                 goto errout;
1602
1603         expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
1604         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires,
1605                                rt->dst.error) < 0)
1606                 goto errout;
1607
1608         if (dn_is_input_route(rt) &&
1609             nla_put_u32(skb, RTA_IIF, rt->fld.flowidn_iif) < 0)
1610                 goto errout;
1611
1612         nlmsg_end(skb, nlh);
1613         return 0;
1614
1615 errout:
1616         nlmsg_cancel(skb, nlh);
1617         return -EMSGSIZE;
1618 }
1619
1620 const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
1621         [RTA_DST]               = { .type = NLA_U16 },
1622         [RTA_SRC]               = { .type = NLA_U16 },
1623         [RTA_IIF]               = { .type = NLA_U32 },
1624         [RTA_OIF]               = { .type = NLA_U32 },
1625         [RTA_GATEWAY]           = { .type = NLA_U16 },
1626         [RTA_PRIORITY]          = { .type = NLA_U32 },
1627         [RTA_PREFSRC]           = { .type = NLA_U16 },
1628         [RTA_METRICS]           = { .type = NLA_NESTED },
1629         [RTA_MULTIPATH]         = { .type = NLA_NESTED },
1630         [RTA_TABLE]             = { .type = NLA_U32 },
1631         [RTA_MARK]              = { .type = NLA_U32 },
1632 };
1633
1634 /*
1635  * This is called by both endnodes and routers now.
1636  */
1637 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
1638 {
1639         struct net *net = sock_net(in_skb->sk);
1640         struct rtmsg *rtm = nlmsg_data(nlh);
1641         struct dn_route *rt = NULL;
1642         struct dn_skb_cb *cb;
1643         int err;
1644         struct sk_buff *skb;
1645         struct flowidn fld;
1646         struct nlattr *tb[RTA_MAX+1];
1647
1648         if (!net_eq(net, &init_net))
1649                 return -EINVAL;
1650
1651         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_dn_policy);
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->dst.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->dst.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
1852 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1853 {
1854         return seq_open_private(file, &dn_rt_cache_seq_ops,
1855                         sizeof(struct dn_rt_cache_iter_state));
1856 }
1857
1858 static const struct file_operations dn_rt_cache_seq_fops = {
1859         .owner   = THIS_MODULE,
1860         .open    = dn_rt_cache_seq_open,
1861         .read    = seq_read,
1862         .llseek  = seq_lseek,
1863         .release = seq_release_private,
1864 };
1865
1866 #endif /* CONFIG_PROC_FS */
1867
1868 void __init dn_route_init(void)
1869 {
1870         int i, goal, order;
1871
1872         dn_dst_ops.kmem_cachep =
1873                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1874                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1875         dst_entries_init(&dn_dst_ops);
1876         setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1877         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1878         add_timer(&dn_route_timer);
1879
1880         goal = totalram_pages >> (26 - PAGE_SHIFT);
1881
1882         for(order = 0; (1UL << order) < goal; order++)
1883                 /* NOTHING */;
1884
1885         /*
1886          * Only want 1024 entries max, since the table is very, very unlikely
1887          * to be larger than that.
1888          */
1889         while(order && ((((1UL << order) * PAGE_SIZE) /
1890                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1891                 order--;
1892
1893         do {
1894                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1895                         sizeof(struct dn_rt_hash_bucket);
1896                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1897                         dn_rt_hash_mask--;
1898                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1899                         __get_free_pages(GFP_ATOMIC, order);
1900         } while (dn_rt_hash_table == NULL && --order > 0);
1901
1902         if (!dn_rt_hash_table)
1903                 panic("Failed to allocate DECnet route cache hash table\n");
1904
1905         printk(KERN_INFO
1906                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1907                 dn_rt_hash_mask,
1908                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1909
1910         dn_rt_hash_mask--;
1911         for(i = 0; i <= dn_rt_hash_mask; i++) {
1912                 spin_lock_init(&dn_rt_hash_table[i].lock);
1913                 dn_rt_hash_table[i].chain = NULL;
1914         }
1915
1916         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1917
1918         proc_create("decnet_cache", S_IRUGO, init_net.proc_net,
1919                     &dn_rt_cache_seq_fops);
1920
1921 #ifdef CONFIG_DECNET_ROUTER
1922         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1923                       dn_fib_dump, NULL);
1924 #else
1925         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1926                       dn_cache_dump, NULL);
1927 #endif
1928 }
1929
1930 void __exit dn_route_cleanup(void)
1931 {
1932         del_timer(&dn_route_timer);
1933         dn_run_flush(0);
1934
1935         remove_proc_entry("decnet_cache", init_net.proc_net);
1936         dst_entries_destroy(&dn_dst_ops);
1937 }
1938