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 <asm/errno.h>
  81 #include <net/net_namespace.h>
  82 #include <net/netlink.h>
  83 #include <net/neighbour.h>
  84 #include <net/dst.h>
  85 #include <net/flow.h>
  86 #include <net/fib_rules.h>
  87 #include <net/dn.h>
  88 #include <net/dn_dev.h>
  89 #include <net/dn_nsp.h>
  90 #include <net/dn_route.h>
  91 #include <net/dn_neigh.h>
  92 #include <net/dn_fib.h>
  93
  94 struct dn_rt_hash_bucket
  95 {
  96         struct dn_route __rcu *chain;
  97         spinlock_t lock;
  98 };
  99
 100 extern struct neigh_table dn_neigh_table;
 101
 102
 103 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 104
 105 static const int dn_rt_min_delay = 2 * HZ;
 106 static const int dn_rt_max_delay = 10 * HZ;
 107 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 108
 109 static unsigned long dn_rt_deadline;
 110
 111 static int dn_dst_gc(struct dst_ops *ops);
 112 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 113 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 114 static void dn_dst_link_failure(struct sk_buff *);
 115 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
 116 static int dn_route_input(struct sk_buff *);
 117 static void dn_run_flush(unsigned long dummy);
 118
 119 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 120 static unsigned dn_rt_hash_mask;
 121
 122 static struct timer_list dn_route_timer;
 123 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 124 int decnet_dst_gc_interval = 2;
 125
 126 static struct dst_ops dn_dst_ops = {
 127         .family =               PF_DECnet,
 128         .protocol =             cpu_to_be16(ETH_P_DNA_RT),
 129         .gc_thresh =            128,
 130         .gc =                   dn_dst_gc,
 131         .check =                dn_dst_check,
 132         .negative_advice =      dn_dst_negative_advice,
 133         .link_failure =         dn_dst_link_failure,
 134         .update_pmtu =          dn_dst_update_pmtu,
 135 };
 136
 137 static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
 138 {
 139         __u16 tmp = (__u16 __force)(src ^ dst);
 140         tmp ^= (tmp >> 3);
 141         tmp ^= (tmp >> 5);
 142         tmp ^= (tmp >> 10);
 143         return dn_rt_hash_mask & (unsigned)tmp;
 144 }
 145
 146 static inline void dnrt_free(struct dn_route *rt)
 147 {
 148         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 149 }
 150
 151 static inline void dnrt_drop(struct dn_route *rt)
 152 {
 153         dst_release(&rt->dst);
 154         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 155 }
 156
 157 static void dn_dst_check_expire(unsigned long dummy)
 158 {
 159         int i;
 160         struct dn_route *rt;
 161         struct dn_route __rcu **rtp;
 162         unsigned long now = jiffies;
 163         unsigned long expire = 120 * HZ;
 164
 165         for (i = 0; i <= dn_rt_hash_mask; i++) {
 166                 rtp = &dn_rt_hash_table[i].chain;
 167
 168                 spin_lock(&dn_rt_hash_table[i].lock);
 169                 while ((rt = rcu_dereference_protected(*rtp,
 170                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 171                         if (atomic_read(&rt->dst.__refcnt) ||
 172                                         (now - rt->dst.lastuse) < expire) {
 173                                 rtp = &rt->dst.dn_next;
 174                                 continue;
 175                         }
 176                         *rtp = rt->dst.dn_next;
 177                         rt->dst.dn_next = NULL;
 178                         dnrt_free(rt);
 179                 }
 180                 spin_unlock(&dn_rt_hash_table[i].lock);
 181
 182                 if ((jiffies - now) > 0)
 183                         break;
 184         }
 185
 186         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 187 }
 188
 189 static int dn_dst_gc(struct dst_ops *ops)
 190 {
 191         struct dn_route *rt;
 192         struct dn_route __rcu **rtp;
 193         int i;
 194         unsigned long now = jiffies;
 195         unsigned long expire = 10 * HZ;
 196
 197         for (i = 0; i <= dn_rt_hash_mask; i++) {
 198
 199                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 200                 rtp = &dn_rt_hash_table[i].chain;
 201
 202                 while ((rt = rcu_dereference_protected(*rtp,
 203                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 204                         if (atomic_read(&rt->dst.__refcnt) ||
 205                                         (now - rt->dst.lastuse) < expire) {
 206                                 rtp = &rt->dst.dn_next;
 207                                 continue;
 208                         }
 209                         *rtp = rt->dst.dn_next;
 210                         rt->dst.dn_next = NULL;
 211                         dnrt_drop(rt);
 212                         break;
 213                 }
 214                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 215         }
 216
 217         return 0;
 218 }
 219
 220 /*
 221  * The decnet standards don't impose a particular minimum mtu, what they
 222  * do insist on is that the routing layer accepts a datagram of at least
 223  * 230 bytes long. Here we have to subtract the routing header length from
 224  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 225  * assume the worst and use a long header size.
 226  *
 227  * We update both the mtu and the advertised mss (i.e. the segment size we
 228  * advertise to the other end).
 229  */
 230 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
 231 {
 232         u32 min_mtu = 230;
 233         struct dn_dev *dn = dst->neighbour ?
 234                             rcu_dereference_raw(dst->neighbour->dev->dn_ptr) : NULL;
 235
 236         if (dn && dn->use_long == 0)
 237                 min_mtu -= 6;
 238         else
 239                 min_mtu -= 21;
 240
 241         if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
 242                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
 243                         dst_metric_set(dst, RTAX_MTU, mtu);
 244                         dst_set_expires(dst, dn_rt_mtu_expires);
 245                 }
 246                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 247                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 248                         if (dst_metric(dst, RTAX_ADVMSS) > mss)
 249                                 dst_metric_set(dst, RTAX_ADVMSS, mss);
 250                 }
 251         }
 252 }
 253
 254 /*
 255  * When a route has been marked obsolete. (e.g. routing cache flush)
 256  */
 257 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 258 {
 259         return NULL;
 260 }
 261
 262 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 263 {
 264         dst_release(dst);
 265         return NULL;
 266 }
 267
 268 static void dn_dst_link_failure(struct sk_buff *skb)
 269 {
 270 }
 271
 272 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
 273 {
 274         return ((fl1->fld_dst ^ fl2->fld_dst) |
 275                 (fl1->fld_src ^ fl2->fld_src) |
 276                 (fl1->mark ^ fl2->mark) |
 277                 (fl1->fld_scope ^ fl2->fld_scope) |
 278                 (fl1->oif ^ fl2->oif) |
 279                 (fl1->iif ^ fl2->iif)) == 0;
 280 }
 281
 282 static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
 283 {
 284         struct dn_route *rth;
 285         struct dn_route __rcu **rthp;
 286         unsigned long now = jiffies;
 287
 288         rthp = &dn_rt_hash_table[hash].chain;
 289
 290         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 291         while ((rth = rcu_dereference_protected(*rthp,
 292                                                 lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
 293                 if (compare_keys(&rth->fl, &rt->fl)) {
 294                         /* Put it first */
 295                         *rthp = rth->dst.dn_next;
 296                         rcu_assign_pointer(rth->dst.dn_next,
 297                                            dn_rt_hash_table[hash].chain);
 298                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 299
 300                         dst_use(&rth->dst, now);
 301                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 302
 303                         dnrt_drop(rt);
 304                         *rp = rth;
 305                         return 0;
 306                 }
 307                 rthp = &rth->dst.dn_next;
 308         }
 309
 310         rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain);
 311         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 312
 313         dst_use(&rt->dst, now);
 314         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 315         *rp = rt;
 316         return 0;
 317 }
 318
 319 static void dn_run_flush(unsigned long dummy)
 320 {
 321         int i;
 322         struct dn_route *rt, *next;
 323
 324         for (i = 0; i < dn_rt_hash_mask; i++) {
 325                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 326
 327                 if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
 328                         goto nothing_to_declare;
 329
 330                 for(; rt; rt = next) {
 331                         next = rcu_dereference_raw(rt->dst.dn_next);
 332                         RCU_INIT_POINTER(rt->dst.dn_next, NULL);
 333                         dst_free((struct dst_entry *)rt);
 334                 }
 335
 336 nothing_to_declare:
 337                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 338         }
 339 }
 340
 341 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 342
 343 void dn_rt_cache_flush(int delay)
 344 {
 345         unsigned long now = jiffies;
 346         int user_mode = !in_interrupt();
 347
 348         if (delay < 0)
 349                 delay = dn_rt_min_delay;
 350
 351         spin_lock_bh(&dn_rt_flush_lock);
 352
 353         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 354                 long tmo = (long)(dn_rt_deadline - now);
 355
 356                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 357                         tmo = 0;
 358
 359                 if (delay > tmo)
 360                         delay = tmo;
 361         }
 362
 363         if (delay <= 0) {
 364                 spin_unlock_bh(&dn_rt_flush_lock);
 365                 dn_run_flush(0);
 366                 return;
 367         }
 368
 369         if (dn_rt_deadline == 0)
 370                 dn_rt_deadline = now + dn_rt_max_delay;
 371
 372         dn_rt_flush_timer.expires = now + delay;
 373         add_timer(&dn_rt_flush_timer);
 374         spin_unlock_bh(&dn_rt_flush_lock);
 375 }
 376
 377 /**
 378  * dn_return_short - Return a short packet to its sender
 379  * @skb: The packet to return
 380  *
 381  */
 382 static int dn_return_short(struct sk_buff *skb)
 383 {
 384         struct dn_skb_cb *cb;
 385         unsigned char *ptr;
 386         __le16 *src;
 387         __le16 *dst;
 388
 389         /* Add back headers */
 390         skb_push(skb, skb->data - skb_network_header(skb));
 391
 392         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 393                 return NET_RX_DROP;
 394
 395         cb = DN_SKB_CB(skb);
 396         /* Skip packet length and point to flags */
 397         ptr = skb->data + 2;
 398         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 399
 400         dst = (__le16 *)ptr;
 401         ptr += 2;
 402         src = (__le16 *)ptr;
 403         ptr += 2;
 404         *ptr = 0; /* Zero hop count */
 405
 406         swap(*src, *dst);
 407
 408         skb->pkt_type = PACKET_OUTGOING;
 409         dn_rt_finish_output(skb, NULL, NULL);
 410         return NET_RX_SUCCESS;
 411 }
 412
 413 /**
 414  * dn_return_long - Return a long packet to its sender
 415  * @skb: The long format packet to return
 416  *
 417  */
 418 static int dn_return_long(struct sk_buff *skb)
 419 {
 420         struct dn_skb_cb *cb;
 421         unsigned char *ptr;
 422         unsigned char *src_addr, *dst_addr;
 423         unsigned char tmp[ETH_ALEN];
 424
 425         /* Add back all 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         /* Ignore packet length and point to flags */
 433         ptr = skb->data + 2;
 434
 435         /* Skip padding */
 436         if (*ptr & DN_RT_F_PF) {
 437                 char padlen = (*ptr & ~DN_RT_F_PF);
 438                 ptr += padlen;
 439         }
 440
 441         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 442         ptr += 2;
 443         dst_addr = ptr;
 444         ptr += 8;
 445         src_addr = ptr;
 446         ptr += 6;
 447         *ptr = 0; /* Zero hop count */
 448
 449         /* Swap source and destination */
 450         memcpy(tmp, src_addr, ETH_ALEN);
 451         memcpy(src_addr, dst_addr, ETH_ALEN);
 452         memcpy(dst_addr, tmp, ETH_ALEN);
 453
 454         skb->pkt_type = PACKET_OUTGOING;
 455         dn_rt_finish_output(skb, dst_addr, src_addr);
 456         return NET_RX_SUCCESS;
 457 }
 458
 459 /**
 460  * dn_route_rx_packet - Try and find a route for an incoming packet
 461  * @skb: The packet to find a route for
 462  *
 463  * Returns: result of input function if route is found, error code otherwise
 464  */
 465 static int dn_route_rx_packet(struct sk_buff *skb)
 466 {
 467         struct dn_skb_cb *cb;
 468         int err;
 469
 470         if ((err = dn_route_input(skb)) == 0)
 471                 return dst_input(skb);
 472
 473         cb = DN_SKB_CB(skb);
 474         if (decnet_debug_level & 4) {
 475                 char *devname = skb->dev ? skb->dev->name : "???";
 476
 477                 printk(KERN_DEBUG
 478                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 479                         (int)cb->rt_flags, devname, skb->len,
 480                         le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
 481                         err, skb->pkt_type);
 482         }
 483
 484         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 485                 switch(cb->rt_flags & DN_RT_PKT_MSK) {
 486                         case DN_RT_PKT_SHORT:
 487                                 return dn_return_short(skb);
 488                         case DN_RT_PKT_LONG:
 489                                 return dn_return_long(skb);
 490                 }
 491         }
 492
 493         kfree_skb(skb);
 494         return NET_RX_DROP;
 495 }
 496
 497 static int dn_route_rx_long(struct sk_buff *skb)
 498 {
 499         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 500         unsigned char *ptr = skb->data;
 501
 502         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 503                 goto drop_it;
 504
 505         skb_pull(skb, 20);
 506         skb_reset_transport_header(skb);
 507
 508         /* Destination info */
 509         ptr += 2;
 510         cb->dst = dn_eth2dn(ptr);
 511         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 512                 goto drop_it;
 513         ptr += 6;
 514
 515
 516         /* Source info */
 517         ptr += 2;
 518         cb->src = dn_eth2dn(ptr);
 519         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 520                 goto drop_it;
 521         ptr += 6;
 522         /* Other junk */
 523         ptr++;
 524         cb->hops = *ptr++; /* Visit Count */
 525
 526         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 527                        dn_route_rx_packet);
 528
 529 drop_it:
 530         kfree_skb(skb);
 531         return NET_RX_DROP;
 532 }
 533
 534
 535
 536 static int dn_route_rx_short(struct sk_buff *skb)
 537 {
 538         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 539         unsigned char *ptr = skb->data;
 540
 541         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 542                 goto drop_it;
 543
 544         skb_pull(skb, 5);
 545         skb_reset_transport_header(skb);
 546
 547         cb->dst = *(__le16 *)ptr;
 548         ptr += 2;
 549         cb->src = *(__le16 *)ptr;
 550         ptr += 2;
 551         cb->hops = *ptr & 0x3f;
 552
 553         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 554                        dn_route_rx_packet);
 555
 556 drop_it:
 557         kfree_skb(skb);
 558         return NET_RX_DROP;
 559 }
 560
 561 static int dn_route_discard(struct sk_buff *skb)
 562 {
 563         /*
 564          * I know we drop the packet here, but thats considered success in
 565          * this case
 566          */
 567         kfree_skb(skb);
 568         return NET_RX_SUCCESS;
 569 }
 570
 571 static int dn_route_ptp_hello(struct sk_buff *skb)
 572 {
 573         dn_dev_hello(skb);
 574         dn_neigh_pointopoint_hello(skb);
 575         return NET_RX_SUCCESS;
 576 }
 577
 578 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 579 {
 580         struct dn_skb_cb *cb;
 581         unsigned char flags = 0;
 582         __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 583         struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
 584         unsigned char padlen = 0;
 585
 586         if (!net_eq(dev_net(dev), &init_net))
 587                 goto dump_it;
 588
 589         if (dn == NULL)
 590                 goto dump_it;
 591
 592         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 593                 goto out;
 594
 595         if (!pskb_may_pull(skb, 3))
 596                 goto dump_it;
 597
 598         skb_pull(skb, 2);
 599
 600         if (len > skb->len)
 601                 goto dump_it;
 602
 603         skb_trim(skb, len);
 604
 605         flags = *skb->data;
 606
 607         cb = DN_SKB_CB(skb);
 608         cb->stamp = jiffies;
 609         cb->iif = dev->ifindex;
 610
 611         /*
 612          * If we have padding, remove it.
 613          */
 614         if (flags & DN_RT_F_PF) {
 615                 padlen = flags & ~DN_RT_F_PF;
 616                 if (!pskb_may_pull(skb, padlen + 1))
 617                         goto dump_it;
 618                 skb_pull(skb, padlen);
 619                 flags = *skb->data;
 620         }
 621
 622         skb_reset_network_header(skb);
 623
 624         /*
 625          * Weed out future version DECnet
 626          */
 627         if (flags & DN_RT_F_VER)
 628                 goto dump_it;
 629
 630         cb->rt_flags = flags;
 631
 632         if (decnet_debug_level & 1)
 633                 printk(KERN_DEBUG
 634                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 635                         (int)flags, (dev) ? dev->name : "???", len, skb->len,
 636                         padlen);
 637
 638         if (flags & DN_RT_PKT_CNTL) {
 639                 if (unlikely(skb_linearize(skb)))
 640                         goto dump_it;
 641
 642                 switch(flags & DN_RT_CNTL_MSK) {
 643                         case DN_RT_PKT_INIT:
 644                                 dn_dev_init_pkt(skb);
 645                                 break;
 646                         case DN_RT_PKT_VERI:
 647                                 dn_dev_veri_pkt(skb);
 648                                 break;
 649                 }
 650
 651                 if (dn->parms.state != DN_DEV_S_RU)
 652                         goto dump_it;
 653
 654                 switch(flags & DN_RT_CNTL_MSK) {
 655                         case DN_RT_PKT_HELO:
 656                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 657                                                skb, skb->dev, NULL,
 658                                                dn_route_ptp_hello);
 659
 660                         case DN_RT_PKT_L1RT:
 661                         case DN_RT_PKT_L2RT:
 662                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
 663                                                skb, skb->dev, NULL,
 664                                                dn_route_discard);
 665                         case DN_RT_PKT_ERTH:
 666                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 667                                                skb, skb->dev, NULL,
 668                                                dn_neigh_router_hello);
 669
 670                         case DN_RT_PKT_EEDH:
 671                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 672                                                skb, skb->dev, NULL,
 673                                                dn_neigh_endnode_hello);
 674                 }
 675         } else {
 676                 if (dn->parms.state != DN_DEV_S_RU)
 677                         goto dump_it;
 678
 679                 skb_pull(skb, 1); /* Pull flags */
 680
 681                 switch(flags & DN_RT_PKT_MSK) {
 682                         case DN_RT_PKT_LONG:
 683                                 return dn_route_rx_long(skb);
 684                         case DN_RT_PKT_SHORT:
 685                                 return dn_route_rx_short(skb);
 686                 }
 687         }
 688
 689 dump_it:
 690         kfree_skb(skb);
 691 out:
 692         return NET_RX_DROP;
 693 }
 694
 695 static int dn_output(struct sk_buff *skb)
 696 {
 697         struct dst_entry *dst = skb_dst(skb);
 698         struct dn_route *rt = (struct dn_route *)dst;
 699         struct net_device *dev = dst->dev;
 700         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 701         struct neighbour *neigh;
 702
 703         int err = -EINVAL;
 704
 705         if ((neigh = dst->neighbour) == NULL)
 706                 goto error;
 707
 708         skb->dev = dev;
 709
 710         cb->src = rt->rt_saddr;
 711         cb->dst = rt->rt_daddr;
 712
 713         /*
 714          * Always set the Intra-Ethernet bit on all outgoing packets
 715          * originated on this node. Only valid flag from upper layers
 716          * is return-to-sender-requested. Set hop count to 0 too.
 717          */
 718         cb->rt_flags &= ~DN_RT_F_RQR;
 719         cb->rt_flags |= DN_RT_F_IE;
 720         cb->hops = 0;
 721
 722         return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, skb, NULL, dev,
 723                        neigh->output);
 724
 725 error:
 726         if (net_ratelimit())
 727                 printk(KERN_DEBUG "dn_output: This should not happen\n");
 728
 729         kfree_skb(skb);
 730
 731         return err;
 732 }
 733
 734 static int dn_forward(struct sk_buff *skb)
 735 {
 736         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 737         struct dst_entry *dst = skb_dst(skb);
 738         struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
 739         struct dn_route *rt;
 740         struct neighbour *neigh = dst->neighbour;
 741         int header_len;
 742 #ifdef CONFIG_NETFILTER
 743         struct net_device *dev = skb->dev;
 744 #endif
 745
 746         if (skb->pkt_type != PACKET_HOST)
 747                 goto drop;
 748
 749         /* Ensure that we have enough space for headers */
 750         rt = (struct dn_route *)skb_dst(skb);
 751         header_len = dn_db->use_long ? 21 : 6;
 752         if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
 753                 goto drop;
 754
 755         /*
 756          * Hop count exceeded.
 757          */
 758         if (++cb->hops > 30)
 759                 goto drop;
 760
 761         skb->dev = rt->dst.dev;
 762
 763         /*
 764          * If packet goes out same interface it came in on, then set
 765          * the Intra-Ethernet bit. This has no effect for short
 766          * packets, so we don't need to test for them here.
 767          */
 768         cb->rt_flags &= ~DN_RT_F_IE;
 769         if (rt->rt_flags & RTCF_DOREDIRECT)
 770                 cb->rt_flags |= DN_RT_F_IE;
 771
 772         return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, skb, dev, skb->dev,
 773                        neigh->output);
 774
 775 drop:
 776         kfree_skb(skb);
 777         return NET_RX_DROP;
 778 }
 779
 780 /*
 781  * Used to catch bugs. This should never normally get
 782  * called.
 783  */
 784 static int dn_rt_bug(struct sk_buff *skb)
 785 {
 786         if (net_ratelimit()) {
 787                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 788
 789                 printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
 790                                 le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 791         }
 792
 793         kfree_skb(skb);
 794
 795         return NET_RX_DROP;
 796 }
 797
 798 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 799 {
 800         struct dn_fib_info *fi = res->fi;
 801         struct net_device *dev = rt->dst.dev;
 802         struct neighbour *n;
 803         unsigned mss;
 804
 805         if (fi) {
 806                 if (DN_FIB_RES_GW(*res) &&
 807                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 808                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 809                 dst_import_metrics(&rt->dst, fi->fib_metrics);
 810         }
 811         rt->rt_type = res->type;
 812
 813         if (dev != NULL && rt->dst.neighbour == NULL) {
 814                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 815                 if (IS_ERR(n))
 816                         return PTR_ERR(n);
 817                 rt->dst.neighbour = n;
 818         }
 819
 820         if (dst_metric(&rt->dst, RTAX_MTU) == 0 ||
 821             dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
 822                 dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
 823         mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
 824         if (dst_metric(&rt->dst, RTAX_ADVMSS) == 0 ||
 825             dst_metric(&rt->dst, RTAX_ADVMSS) > mss)
 826                 dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
 827         return 0;
 828 }
 829
 830 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 831 {
 832         __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 833         int match = 16;
 834         while(tmp) {
 835                 tmp >>= 1;
 836                 match--;
 837         }
 838         return match;
 839 }
 840
 841 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 842 {
 843         __le16 saddr = 0;
 844         struct dn_dev *dn_db;
 845         struct dn_ifaddr *ifa;
 846         int best_match = 0;
 847         int ret;
 848
 849         rcu_read_lock();
 850         dn_db = rcu_dereference(dev->dn_ptr);
 851         for (ifa = rcu_dereference(dn_db->ifa_list);
 852              ifa != NULL;
 853              ifa = rcu_dereference(ifa->ifa_next)) {
 854                 if (ifa->ifa_scope > scope)
 855                         continue;
 856                 if (!daddr) {
 857                         saddr = ifa->ifa_local;
 858                         break;
 859                 }
 860                 ret = dn_match_addr(daddr, ifa->ifa_local);
 861                 if (ret > best_match)
 862                         saddr = ifa->ifa_local;
 863                 if (best_match == 0)
 864                         saddr = ifa->ifa_local;
 865         }
 866         rcu_read_unlock();
 867
 868         return saddr;
 869 }
 870
 871 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 872 {
 873         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 874 }
 875
 876 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 877 {
 878         __le16 mask = dnet_make_mask(res->prefixlen);
 879         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 880 }
 881
 882 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
 883 {
 884         struct flowi fl = { .fld_dst = oldflp->fld_dst,
 885                             .fld_src = oldflp->fld_src,
 886                             .fld_scope = RT_SCOPE_UNIVERSE,
 887                             .mark = oldflp->mark,
 888                             .iif = init_net.loopback_dev->ifindex,
 889                             .oif = oldflp->oif };
 890         struct dn_route *rt = NULL;
 891         struct net_device *dev_out = NULL, *dev;
 892         struct neighbour *neigh = NULL;
 893         unsigned hash;
 894         unsigned flags = 0;
 895         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 896         int err;
 897         int free_res = 0;
 898         __le16 gateway = 0;
 899
 900         if (decnet_debug_level & 16)
 901                 printk(KERN_DEBUG
 902                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 903                        " iif=%d oif=%d\n", le16_to_cpu(oldflp->fld_dst),
 904                        le16_to_cpu(oldflp->fld_src),
 905                        oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);
 906
 907         /* If we have an output interface, verify its a DECnet device */
 908         if (oldflp->oif) {
 909                 dev_out = dev_get_by_index(&init_net, oldflp->oif);
 910                 err = -ENODEV;
 911                 if (dev_out && dev_out->dn_ptr == NULL) {
 912                         dev_put(dev_out);
 913                         dev_out = NULL;
 914                 }
 915                 if (dev_out == NULL)
 916                         goto out;
 917         }
 918
 919         /* If we have a source address, verify that its a local address */
 920         if (oldflp->fld_src) {
 921                 err = -EADDRNOTAVAIL;
 922
 923                 if (dev_out) {
 924                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
 925                                 goto source_ok;
 926                         dev_put(dev_out);
 927                         goto out;
 928                 }
 929                 rcu_read_lock();
 930                 for_each_netdev_rcu(&init_net, dev) {
 931                         if (!dev->dn_ptr)
 932                                 continue;
 933                         if (!dn_dev_islocal(dev, oldflp->fld_src))
 934                                 continue;
 935                         if ((dev->flags & IFF_LOOPBACK) &&
 936                             oldflp->fld_dst &&
 937                             !dn_dev_islocal(dev, oldflp->fld_dst))
 938                                 continue;
 939
 940                         dev_out = dev;
 941                         break;
 942                 }
 943                 rcu_read_unlock();
 944                 if (dev_out == NULL)
 945                         goto out;
 946                 dev_hold(dev_out);
 947 source_ok:
 948                 ;
 949         }
 950
 951         /* No destination? Assume its local */
 952         if (!fl.fld_dst) {
 953                 fl.fld_dst = fl.fld_src;
 954
 955                 err = -EADDRNOTAVAIL;
 956                 if (dev_out)
 957                         dev_put(dev_out);
 958                 dev_out = init_net.loopback_dev;
 959                 dev_hold(dev_out);
 960                 if (!fl.fld_dst) {
 961                         fl.fld_dst =
 962                         fl.fld_src = dnet_select_source(dev_out, 0,
 963                                                        RT_SCOPE_HOST);
 964                         if (!fl.fld_dst)
 965                                 goto out;
 966                 }
 967                 fl.oif = init_net.loopback_dev->ifindex;
 968                 res.type = RTN_LOCAL;
 969                 goto make_route;
 970         }
 971
 972         if (decnet_debug_level & 16)
 973                 printk(KERN_DEBUG
 974                        "dn_route_output_slow: initial checks complete."
 975                        " dst=%o4x src=%04x oif=%d try_hard=%d\n",
 976                        le16_to_cpu(fl.fld_dst), le16_to_cpu(fl.fld_src),
 977                        fl.oif, try_hard);
 978
 979         /*
 980          * N.B. If the kernel is compiled without router support then
 981          * dn_fib_lookup() will evaluate to non-zero so this if () block
 982          * will always be executed.
 983          */
 984         err = -ESRCH;
 985         if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
 986                 struct dn_dev *dn_db;
 987                 if (err != -ESRCH)
 988                         goto out;
 989                 /*
 990                  * Here the fallback is basically the standard algorithm for
 991                  * routing in endnodes which is described in the DECnet routing
 992                  * docs
 993                  *
 994                  * If we are not trying hard, look in neighbour cache.
 995                  * The result is tested to ensure that if a specific output
 996                  * device/source address was requested, then we honour that
 997                  * here
 998                  */
 999                 if (!try_hard) {
1000                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fl.fld_dst);
1001                         if (neigh) {
1002                                 if ((oldflp->oif &&
1003                                     (neigh->dev->ifindex != oldflp->oif)) ||
1004                                     (oldflp->fld_src &&
1005                                     (!dn_dev_islocal(neigh->dev,
1006                                                       oldflp->fld_src)))) {
1007                                         neigh_release(neigh);
1008                                         neigh = NULL;
1009                                 } else {
1010                                         if (dev_out)
1011                                                 dev_put(dev_out);
1012                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
1013                                                 dev_out = init_net.loopback_dev;
1014                                                 res.type = RTN_LOCAL;
1015                                         } else {
1016                                                 dev_out = neigh->dev;
1017                                         }
1018                                         dev_hold(dev_out);
1019                                         goto select_source;
1020                                 }
1021                         }
1022                 }
1023
1024                 /* Not there? Perhaps its a local address */
1025                 if (dev_out == NULL)
1026                         dev_out = dn_dev_get_default();
1027                 err = -ENODEV;
1028                 if (dev_out == NULL)
1029                         goto out;
1030                 dn_db = rcu_dereference_raw(dev_out->dn_ptr);
1031                 /* Possible improvement - check all devices for local addr */
1032                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1033                         dev_put(dev_out);
1034                         dev_out = init_net.loopback_dev;
1035                         dev_hold(dev_out);
1036                         res.type = RTN_LOCAL;
1037                         goto select_source;
1038                 }
1039                 /* Not local either.... try sending it to the default router */
1040                 neigh = neigh_clone(dn_db->router);
1041                 BUG_ON(neigh && neigh->dev != dev_out);
1042
1043                 /* Ok then, we assume its directly connected and move on */
1044 select_source:
1045                 if (neigh)
1046                         gateway = ((struct dn_neigh *)neigh)->addr;
1047                 if (gateway == 0)
1048                         gateway = fl.fld_dst;
1049                 if (fl.fld_src == 0) {
1050                         fl.fld_src = dnet_select_source(dev_out, gateway,
1051                                                          res.type == RTN_LOCAL ?
1052                                                          RT_SCOPE_HOST :
1053                                                          RT_SCOPE_LINK);
1054                         if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1055                                 goto e_addr;
1056                 }
1057                 fl.oif = dev_out->ifindex;
1058                 goto make_route;
1059         }
1060         free_res = 1;
1061
1062         if (res.type == RTN_NAT)
1063                 goto e_inval;
1064
1065         if (res.type == RTN_LOCAL) {
1066                 if (!fl.fld_src)
1067                         fl.fld_src = fl.fld_dst;
1068                 if (dev_out)
1069                         dev_put(dev_out);
1070                 dev_out = init_net.loopback_dev;
1071                 dev_hold(dev_out);
1072                 fl.oif = dev_out->ifindex;
1073                 if (res.fi)
1074                         dn_fib_info_put(res.fi);
1075                 res.fi = NULL;
1076                 goto make_route;
1077         }
1078
1079         if (res.fi->fib_nhs > 1 && fl.oif == 0)
1080                 dn_fib_select_multipath(&fl, &res);
1081
1082         /*
1083          * We could add some logic to deal with default routes here and
1084          * get rid of some of the special casing above.
1085          */
1086
1087         if (!fl.fld_src)
1088                 fl.fld_src = DN_FIB_RES_PREFSRC(res);
1089
1090         if (dev_out)
1091                 dev_put(dev_out);
1092         dev_out = DN_FIB_RES_DEV(res);
1093         dev_hold(dev_out);
1094         fl.oif = dev_out->ifindex;
1095         gateway = DN_FIB_RES_GW(res);
1096
1097 make_route:
1098         if (dev_out->flags & IFF_LOOPBACK)
1099                 flags |= RTCF_LOCAL;
1100
1101         rt = dst_alloc(&dn_dst_ops);
1102         if (rt == NULL)
1103                 goto e_nobufs;
1104
1105         atomic_set(&rt->dst.__refcnt, 1);
1106         rt->dst.flags   = DST_HOST;
1107
1108         rt->fl.fld_src    = oldflp->fld_src;
1109         rt->fl.fld_dst    = oldflp->fld_dst;
1110         rt->fl.oif        = oldflp->oif;
1111         rt->fl.iif        = 0;
1112         rt->fl.mark       = oldflp->mark;
1113
1114         rt->rt_saddr      = fl.fld_src;
1115         rt->rt_daddr      = fl.fld_dst;
1116         rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1117         rt->rt_local_src  = fl.fld_src;
1118
1119         rt->rt_dst_map    = fl.fld_dst;
1120         rt->rt_src_map    = fl.fld_src;
1121
1122         rt->dst.dev = dev_out;
1123         dev_hold(dev_out);
1124         rt->dst.neighbour = neigh;
1125         neigh = NULL;
1126
1127         rt->dst.lastuse = jiffies;
1128         rt->dst.output  = dn_output;
1129         rt->dst.input   = dn_rt_bug;
1130         rt->rt_flags      = flags;
1131         if (flags & RTCF_LOCAL)
1132                 rt->dst.input = dn_nsp_rx;
1133
1134         err = dn_rt_set_next_hop(rt, &res);
1135         if (err)
1136                 goto e_neighbour;
1137
1138         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1139         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1140
1141 done:
1142         if (neigh)
1143                 neigh_release(neigh);
1144         if (free_res)
1145                 dn_fib_res_put(&res);
1146         if (dev_out)
1147                 dev_put(dev_out);
1148 out:
1149         return err;
1150
1151 e_addr:
1152         err = -EADDRNOTAVAIL;
1153         goto done;
1154 e_inval:
1155         err = -EINVAL;
1156         goto done;
1157 e_nobufs:
1158         err = -ENOBUFS;
1159         goto done;
1160 e_neighbour:
1161         dst_free(&rt->dst);
1162         goto e_nobufs;
1163 }
1164
1165
1166 /*
1167  * N.B. The flags may be moved into the flowi at some future stage.
1168  */
1169 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1170 {
1171         unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1172         struct dn_route *rt = NULL;
1173
1174         if (!(flags & MSG_TRYHARD)) {
1175                 rcu_read_lock_bh();
1176                 for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1177                         rt = rcu_dereference_bh(rt->dst.dn_next)) {
1178                         if ((flp->fld_dst == rt->fl.fld_dst) &&
1179                             (flp->fld_src == rt->fl.fld_src) &&
1180                             (flp->mark == rt->fl.mark) &&
1181                             dn_is_output_route(rt) &&
1182                             (rt->fl.oif == flp->oif)) {
1183                                 dst_use(&rt->dst, jiffies);
1184                                 rcu_read_unlock_bh();
1185                                 *pprt = &rt->dst;
1186                                 return 0;
1187                         }
1188                 }
1189                 rcu_read_unlock_bh();
1190         }
1191
1192         return dn_route_output_slow(pprt, flp, flags);
1193 }
1194
1195 static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
1196 {
1197         int err;
1198
1199         err = __dn_route_output_key(pprt, flp, flags);
1200         if (err == 0 && flp->proto) {
1201                 err = xfrm_lookup(&init_net, pprt, flp, NULL, 0);
1202         }
1203         return err;
1204 }
1205
1206 int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
1207 {
1208         int err;
1209
1210         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1211         if (err == 0 && fl->proto) {
1212                 err = xfrm_lookup(&init_net, pprt, fl, sk,
1213                                  (flags & MSG_DONTWAIT) ? 0 : XFRM_LOOKUP_WAIT);
1214         }
1215         return err;
1216 }
1217
1218 static int dn_route_input_slow(struct sk_buff *skb)
1219 {
1220         struct dn_route *rt = NULL;
1221         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1222         struct net_device *in_dev = skb->dev;
1223         struct net_device *out_dev = NULL;
1224         struct dn_dev *dn_db;
1225         struct neighbour *neigh = NULL;
1226         unsigned hash;
1227         int flags = 0;
1228         __le16 gateway = 0;
1229         __le16 local_src = 0;
1230         struct flowi fl = { .fld_dst = cb->dst,
1231                             .fld_src = cb->src,
1232                             .fld_scope = RT_SCOPE_UNIVERSE,
1233                             .mark = skb->mark,
1234                             .iif = skb->dev->ifindex };
1235         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1236         int err = -EINVAL;
1237         int free_res = 0;
1238
1239         dev_hold(in_dev);
1240
1241         if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
1242                 goto out;
1243
1244         /* Zero source addresses are not allowed */
1245         if (fl.fld_src == 0)
1246                 goto out;
1247
1248         /*
1249          * In this case we've just received a packet from a source
1250          * outside ourselves pretending to come from us. We don't
1251          * allow it any further to prevent routing loops, spoofing and
1252          * other nasties. Loopback packets already have the dst attached
1253          * so this only affects packets which have originated elsewhere.
1254          */
1255         err  = -ENOTUNIQ;
1256         if (dn_dev_islocal(in_dev, cb->src))
1257                 goto out;
1258
1259         err = dn_fib_lookup(&fl, &res);
1260         if (err) {
1261                 if (err != -ESRCH)
1262                         goto out;
1263                 /*
1264                  * Is the destination us ?
1265                  */
1266                 if (!dn_dev_islocal(in_dev, cb->dst))
1267                         goto e_inval;
1268
1269                 res.type = RTN_LOCAL;
1270         } else {
1271                 __le16 src_map = fl.fld_src;
1272                 free_res = 1;
1273
1274                 out_dev = DN_FIB_RES_DEV(res);
1275                 if (out_dev == NULL) {
1276                         if (net_ratelimit())
1277                                 printk(KERN_CRIT "Bug in dn_route_input_slow() "
1278                                                  "No output device\n");
1279                         goto e_inval;
1280                 }
1281                 dev_hold(out_dev);
1282
1283                 if (res.r)
1284                         src_map = fl.fld_src; /* no NAT support for now */
1285
1286                 gateway = DN_FIB_RES_GW(res);
1287                 if (res.type == RTN_NAT) {
1288                         fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1289                         dn_fib_res_put(&res);
1290                         free_res = 0;
1291                         if (dn_fib_lookup(&fl, &res))
1292                                 goto e_inval;
1293                         free_res = 1;
1294                         if (res.type != RTN_UNICAST)
1295                                 goto e_inval;
1296                         flags |= RTCF_DNAT;
1297                         gateway = fl.fld_dst;
1298                 }
1299                 fl.fld_src = src_map;
1300         }
1301
1302         switch(res.type) {
1303         case RTN_UNICAST:
1304                 /*
1305                  * Forwarding check here, we only check for forwarding
1306                  * being turned off, if you want to only forward intra
1307                  * area, its up to you to set the routing tables up
1308                  * correctly.
1309                  */
1310                 if (dn_db->parms.forwarding == 0)
1311                         goto e_inval;
1312
1313                 if (res.fi->fib_nhs > 1 && fl.oif == 0)
1314                         dn_fib_select_multipath(&fl, &res);
1315
1316                 /*
1317                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1318                  * flag as a hint to set the intra-ethernet bit when
1319                  * forwarding. If we've got NAT in operation, we don't do
1320                  * this optimisation.
1321                  */
1322                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1323                         flags |= RTCF_DOREDIRECT;
1324
1325                 local_src = DN_FIB_RES_PREFSRC(res);
1326
1327         case RTN_BLACKHOLE:
1328         case RTN_UNREACHABLE:
1329                 break;
1330         case RTN_LOCAL:
1331                 flags |= RTCF_LOCAL;
1332                 fl.fld_src = cb->dst;
1333                 fl.fld_dst = cb->src;
1334
1335                 /* Routing tables gave us a gateway */
1336                 if (gateway)
1337                         goto make_route;
1338
1339                 /* Packet was intra-ethernet, so we know its on-link */
1340                 if (cb->rt_flags & DN_RT_F_IE) {
1341                         gateway = cb->src;
1342                         flags |= RTCF_DIRECTSRC;
1343                         goto make_route;
1344                 }
1345
1346                 /* Use the default router if there is one */
1347                 neigh = neigh_clone(dn_db->router);
1348                 if (neigh) {
1349                         gateway = ((struct dn_neigh *)neigh)->addr;
1350                         goto make_route;
1351                 }
1352
1353                 /* Close eyes and pray */
1354                 gateway = cb->src;
1355                 flags |= RTCF_DIRECTSRC;
1356                 goto make_route;
1357         default:
1358                 goto e_inval;
1359         }
1360
1361 make_route:
1362         rt = dst_alloc(&dn_dst_ops);
1363         if (rt == NULL)
1364                 goto e_nobufs;
1365
1366         rt->rt_saddr      = fl.fld_src;
1367         rt->rt_daddr      = fl.fld_dst;
1368         rt->rt_gateway    = fl.fld_dst;
1369         if (gateway)
1370                 rt->rt_gateway = gateway;
1371         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1372
1373         rt->rt_dst_map    = fl.fld_dst;
1374         rt->rt_src_map    = fl.fld_src;
1375
1376         rt->fl.fld_src    = cb->src;
1377         rt->fl.fld_dst    = cb->dst;
1378         rt->fl.oif        = 0;
1379         rt->fl.iif        = in_dev->ifindex;
1380         rt->fl.mark       = fl.mark;
1381
1382         rt->dst.flags = DST_HOST;
1383         rt->dst.neighbour = neigh;
1384         rt->dst.dev = out_dev;
1385         rt->dst.lastuse = jiffies;
1386         rt->dst.output = dn_rt_bug;
1387         switch(res.type) {
1388                 case RTN_UNICAST:
1389                         rt->dst.input = dn_forward;
1390                         break;
1391                 case RTN_LOCAL:
1392                         rt->dst.output = dn_output;
1393                         rt->dst.input = dn_nsp_rx;
1394                         rt->dst.dev = in_dev;
1395                         flags |= RTCF_LOCAL;
1396                         break;
1397                 default:
1398                 case RTN_UNREACHABLE:
1399                 case RTN_BLACKHOLE:
1400                         rt->dst.input = dst_discard;
1401         }
1402         rt->rt_flags = flags;
1403         if (rt->dst.dev)
1404                 dev_hold(rt->dst.dev);
1405
1406         err = dn_rt_set_next_hop(rt, &res);
1407         if (err)
1408                 goto e_neighbour;
1409
1410         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1411         dn_insert_route(rt, hash, &rt);
1412         skb_dst_set(skb, &rt->dst);
1413
1414 done:
1415         if (neigh)
1416                 neigh_release(neigh);
1417         if (free_res)
1418                 dn_fib_res_put(&res);
1419         dev_put(in_dev);
1420         if (out_dev)
1421                 dev_put(out_dev);
1422 out:
1423         return err;
1424
1425 e_inval:
1426         err = -EINVAL;
1427         goto done;
1428
1429 e_nobufs:
1430         err = -ENOBUFS;
1431         goto done;
1432
1433 e_neighbour:
1434         dst_free(&rt->dst);
1435         goto done;
1436 }
1437
1438 static int dn_route_input(struct sk_buff *skb)
1439 {
1440         struct dn_route *rt;
1441         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1442         unsigned hash = dn_hash(cb->src, cb->dst);
1443
1444         if (skb_dst(skb))
1445                 return 0;
1446
1447         rcu_read_lock();
1448         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1449             rt = rcu_dereference(rt->dst.dn_next)) {
1450                 if ((rt->fl.fld_src == cb->src) &&
1451                     (rt->fl.fld_dst == cb->dst) &&
1452                     (rt->fl.oif == 0) &&
1453                     (rt->fl.mark == skb->mark) &&
1454                     (rt->fl.iif == cb->iif)) {
1455                         dst_use(&rt->dst, jiffies);
1456                         rcu_read_unlock();
1457                         skb_dst_set(skb, (struct dst_entry *)rt);
1458                         return 0;
1459                 }
1460         }
1461         rcu_read_unlock();
1462
1463         return dn_route_input_slow(skb);
1464 }
1465
1466 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1467                            int event, int nowait, unsigned int flags)
1468 {
1469         struct dn_route *rt = (struct dn_route *)skb_dst(skb);
1470         struct rtmsg *r;
1471         struct nlmsghdr *nlh;
1472         unsigned char *b = skb_tail_pointer(skb);
1473         long expires;
1474
1475         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1476         r = NLMSG_DATA(nlh);
1477         r->rtm_family = AF_DECnet;
1478         r->rtm_dst_len = 16;
1479         r->rtm_src_len = 0;
1480         r->rtm_tos = 0;
1481         r->rtm_table = RT_TABLE_MAIN;
1482         RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
1483         r->rtm_type = rt->rt_type;
1484         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1485         r->rtm_scope = RT_SCOPE_UNIVERSE;
1486         r->rtm_protocol = RTPROT_UNSPEC;
1487         if (rt->rt_flags & RTCF_NOTIFY)
1488                 r->rtm_flags |= RTM_F_NOTIFY;
1489         RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1490         if (rt->fl.fld_src) {
1491                 r->rtm_src_len = 16;
1492                 RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1493         }
1494         if (rt->dst.dev)
1495                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->dst.dev->ifindex);
1496         /*
1497          * Note to self - change this if input routes reverse direction when
1498          * they deal only with inputs and not with replies like they do
1499          * currently.
1500          */
1501         RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1502         if (rt->rt_daddr != rt->rt_gateway)
1503                 RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1504         if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
1505                 goto rtattr_failure;
1506         expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
1507         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, 0, 0, expires,
1508                                rt->dst.error) < 0)
1509                 goto rtattr_failure;
1510         if (dn_is_input_route(rt))
1511                 RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1512
1513         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1514         return skb->len;
1515
1516 nlmsg_failure:
1517 rtattr_failure:
1518         nlmsg_trim(skb, b);
1519         return -1;
1520 }
1521
1522 /*
1523  * This is called by both endnodes and routers now.
1524  */
1525 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1526 {
1527         struct net *net = sock_net(in_skb->sk);
1528         struct rtattr **rta = arg;
1529         struct rtmsg *rtm = NLMSG_DATA(nlh);
1530         struct dn_route *rt = NULL;
1531         struct dn_skb_cb *cb;
1532         int err;
1533         struct sk_buff *skb;
1534         struct flowi fl;
1535
1536         if (!net_eq(net, &init_net))
1537                 return -EINVAL;
1538
1539         memset(&fl, 0, sizeof(fl));
1540         fl.proto = DNPROTO_NSP;
1541
1542         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1543         if (skb == NULL)
1544                 return -ENOBUFS;
1545         skb_reset_mac_header(skb);
1546         cb = DN_SKB_CB(skb);
1547
1548         if (rta[RTA_SRC-1])
1549                 memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1550         if (rta[RTA_DST-1])
1551                 memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1552         if (rta[RTA_IIF-1])
1553                 memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1554
1555         if (fl.iif) {
1556                 struct net_device *dev;
1557                 if ((dev = dev_get_by_index(&init_net, fl.iif)) == NULL) {
1558                         kfree_skb(skb);
1559                         return -ENODEV;
1560                 }
1561                 if (!dev->dn_ptr) {
1562                         dev_put(dev);
1563                         kfree_skb(skb);
1564                         return -ENODEV;
1565                 }
1566                 skb->protocol = htons(ETH_P_DNA_RT);
1567                 skb->dev = dev;
1568                 cb->src = fl.fld_src;
1569                 cb->dst = fl.fld_dst;
1570                 local_bh_disable();
1571                 err = dn_route_input(skb);
1572                 local_bh_enable();
1573                 memset(cb, 0, sizeof(struct dn_skb_cb));
1574                 rt = (struct dn_route *)skb_dst(skb);
1575                 if (!err && -rt->dst.error)
1576                         err = rt->dst.error;
1577         } else {
1578                 int oif = 0;
1579                 if (rta[RTA_OIF - 1])
1580                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1581                 fl.oif = oif;
1582                 err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1583         }
1584
1585         if (skb->dev)
1586                 dev_put(skb->dev);
1587         skb->dev = NULL;
1588         if (err)
1589                 goto out_free;
1590         skb_dst_set(skb, &rt->dst);
1591         if (rtm->rtm_flags & RTM_F_NOTIFY)
1592                 rt->rt_flags |= RTCF_NOTIFY;
1593
1594         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1595
1596         if (err == 0)
1597                 goto out_free;
1598         if (err < 0) {
1599                 err = -EMSGSIZE;
1600                 goto out_free;
1601         }
1602
1603         return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
1604
1605 out_free:
1606         kfree_skb(skb);
1607         return err;
1608 }
1609
1610 /*
1611  * For routers, this is called from dn_fib_dump, but for endnodes its
1612  * called directly from the rtnetlink dispatch table.
1613  */
1614 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1615 {
1616         struct net *net = sock_net(skb->sk);
1617         struct dn_route *rt;
1618         int h, s_h;
1619         int idx, s_idx;
1620
1621         if (!net_eq(net, &init_net))
1622                 return 0;
1623
1624         if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1625                 return -EINVAL;
1626         if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1627                 return 0;
1628
1629         s_h = cb->args[0];
1630         s_idx = idx = cb->args[1];
1631         for(h = 0; h <= dn_rt_hash_mask; h++) {
1632                 if (h < s_h)
1633                         continue;
1634                 if (h > s_h)
1635                         s_idx = 0;
1636                 rcu_read_lock_bh();
1637                 for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1638                         rt;
1639                         rt = rcu_dereference_bh(rt->dst.dn_next), idx++) {
1640                         if (idx < s_idx)
1641                                 continue;
1642                         skb_dst_set(skb, dst_clone(&rt->dst));
1643                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1644                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1645                                         1, NLM_F_MULTI) <= 0) {
1646                                 skb_dst_drop(skb);
1647                                 rcu_read_unlock_bh();
1648                                 goto done;
1649                         }
1650                         skb_dst_drop(skb);
1651                 }
1652                 rcu_read_unlock_bh();
1653         }
1654
1655 done:
1656         cb->args[0] = h;
1657         cb->args[1] = idx;
1658         return skb->len;
1659 }
1660
1661 #ifdef CONFIG_PROC_FS
1662 struct dn_rt_cache_iter_state {
1663         int bucket;
1664 };
1665
1666 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1667 {
1668         struct dn_route *rt = NULL;
1669         struct dn_rt_cache_iter_state *s = seq->private;
1670
1671         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1672                 rcu_read_lock_bh();
1673                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1674                 if (rt)
1675                         break;
1676                 rcu_read_unlock_bh();
1677         }
1678         return rt;
1679 }
1680
1681 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1682 {
1683         struct dn_rt_cache_iter_state *s = seq->private;
1684
1685         rt = rcu_dereference_bh(rt->dst.dn_next);
1686         while (!rt) {
1687                 rcu_read_unlock_bh();
1688                 if (--s->bucket < 0)
1689                         break;
1690                 rcu_read_lock_bh();
1691                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1692         }
1693         return rt;
1694 }
1695
1696 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1697 {
1698         struct dn_route *rt = dn_rt_cache_get_first(seq);
1699
1700         if (rt) {
1701                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1702                         --*pos;
1703         }
1704         return *pos ? NULL : rt;
1705 }
1706
1707 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1708 {
1709         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1710         ++*pos;
1711         return rt;
1712 }
1713
1714 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1715 {
1716         if (v)
1717                 rcu_read_unlock_bh();
1718 }
1719
1720 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1721 {
1722         struct dn_route *rt = v;
1723         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1724
1725         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1726                         rt->dst.dev ? rt->dst.dev->name : "*",
1727                         dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1728                         dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1729                         atomic_read(&rt->dst.__refcnt),
1730                         rt->dst.__use,
1731                         (int) dst_metric(&rt->dst, RTAX_RTT));
1732         return 0;
1733 }
1734
1735 static const struct seq_operations dn_rt_cache_seq_ops = {
1736         .start  = dn_rt_cache_seq_start,
1737         .next   = dn_rt_cache_seq_next,
1738         .stop   = dn_rt_cache_seq_stop,
1739         .show   = dn_rt_cache_seq_show,
1740 };
1741
1742 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1743 {
1744         return seq_open_private(file, &dn_rt_cache_seq_ops,
1745                         sizeof(struct dn_rt_cache_iter_state));
1746 }
1747
1748 static const struct file_operations dn_rt_cache_seq_fops = {
1749         .owner   = THIS_MODULE,
1750         .open    = dn_rt_cache_seq_open,
1751         .read    = seq_read,
1752         .llseek  = seq_lseek,
1753         .release = seq_release_private,
1754 };
1755
1756 #endif /* CONFIG_PROC_FS */
1757
1758 void __init dn_route_init(void)
1759 {
1760         int i, goal, order;
1761
1762         dn_dst_ops.kmem_cachep =
1763                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1764                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1765         dst_entries_init(&dn_dst_ops);
1766         setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1767         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1768         add_timer(&dn_route_timer);
1769
1770         goal = totalram_pages >> (26 - PAGE_SHIFT);
1771
1772         for(order = 0; (1UL << order) < goal; order++)
1773                 /* NOTHING */;
1774
1775         /*
1776          * Only want 1024 entries max, since the table is very, very unlikely
1777          * to be larger than that.
1778          */
1779         while(order && ((((1UL << order) * PAGE_SIZE) /
1780                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1781                 order--;
1782
1783         do {
1784                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1785                         sizeof(struct dn_rt_hash_bucket);
1786                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1787                         dn_rt_hash_mask--;
1788                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1789                         __get_free_pages(GFP_ATOMIC, order);
1790         } while (dn_rt_hash_table == NULL && --order > 0);
1791
1792         if (!dn_rt_hash_table)
1793                 panic("Failed to allocate DECnet route cache hash table\n");
1794
1795         printk(KERN_INFO
1796                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1797                 dn_rt_hash_mask,
1798                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1799
1800         dn_rt_hash_mask--;
1801         for(i = 0; i <= dn_rt_hash_mask; i++) {
1802                 spin_lock_init(&dn_rt_hash_table[i].lock);
1803                 dn_rt_hash_table[i].chain = NULL;
1804         }
1805
1806         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1807
1808         proc_net_fops_create(&init_net, "decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1809
1810 #ifdef CONFIG_DECNET_ROUTER
1811         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute, dn_fib_dump);
1812 #else
1813         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1814                       dn_cache_dump);
1815 #endif
1816 }
1817
1818 void __exit dn_route_cleanup(void)
1819 {
1820         del_timer(&dn_route_timer);
1821         dn_run_flush(0);
1822
1823         proc_net_remove(&init_net, "decnet_cache");
1824         dst_entries_destroy(&dn_dst_ops);
1825 }
1826