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 unsigned int dn_dst_default_advmss(const struct dst_entry *dst);
 114 static unsigned int dn_dst_default_mtu(const struct dst_entry *dst);
 115 static void dn_dst_destroy(struct dst_entry *);
 116 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 117 static void dn_dst_link_failure(struct sk_buff *);
 118 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
 119 static int dn_route_input(struct sk_buff *);
 120 static void dn_run_flush(unsigned long dummy);
 121
 122 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 123 static unsigned dn_rt_hash_mask;
 124
 125 static struct timer_list dn_route_timer;
 126 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 127 int decnet_dst_gc_interval = 2;
 128
 129 static struct dst_ops dn_dst_ops = {
 130         .family =               PF_DECnet,
 131         .protocol =             cpu_to_be16(ETH_P_DNA_RT),
 132         .gc_thresh =            128,
 133         .gc =                   dn_dst_gc,
 134         .check =                dn_dst_check,
 135         .default_advmss =       dn_dst_default_advmss,
 136         .default_mtu =          dn_dst_default_mtu,
 137         .cow_metrics =          dst_cow_metrics_generic,
 138         .destroy =              dn_dst_destroy,
 139         .negative_advice =      dn_dst_negative_advice,
 140         .link_failure =         dn_dst_link_failure,
 141         .update_pmtu =          dn_dst_update_pmtu,
 142 };
 143
 144 static void dn_dst_destroy(struct dst_entry *dst)
 145 {
 146         dst_destroy_metrics_generic(dst);
 147 }
 148
 149 static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
 150 {
 151         __u16 tmp = (__u16 __force)(src ^ dst);
 152         tmp ^= (tmp >> 3);
 153         tmp ^= (tmp >> 5);
 154         tmp ^= (tmp >> 10);
 155         return dn_rt_hash_mask & (unsigned)tmp;
 156 }
 157
 158 static inline void dnrt_free(struct dn_route *rt)
 159 {
 160         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 161 }
 162
 163 static inline void dnrt_drop(struct dn_route *rt)
 164 {
 165         dst_release(&rt->dst);
 166         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 167 }
 168
 169 static void dn_dst_check_expire(unsigned long dummy)
 170 {
 171         int i;
 172         struct dn_route *rt;
 173         struct dn_route __rcu **rtp;
 174         unsigned long now = jiffies;
 175         unsigned long expire = 120 * HZ;
 176
 177         for (i = 0; i <= dn_rt_hash_mask; i++) {
 178                 rtp = &dn_rt_hash_table[i].chain;
 179
 180                 spin_lock(&dn_rt_hash_table[i].lock);
 181                 while ((rt = rcu_dereference_protected(*rtp,
 182                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 183                         if (atomic_read(&rt->dst.__refcnt) ||
 184                                         (now - rt->dst.lastuse) < expire) {
 185                                 rtp = &rt->dst.dn_next;
 186                                 continue;
 187                         }
 188                         *rtp = rt->dst.dn_next;
 189                         rt->dst.dn_next = NULL;
 190                         dnrt_free(rt);
 191                 }
 192                 spin_unlock(&dn_rt_hash_table[i].lock);
 193
 194                 if ((jiffies - now) > 0)
 195                         break;
 196         }
 197
 198         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 199 }
 200
 201 static int dn_dst_gc(struct dst_ops *ops)
 202 {
 203         struct dn_route *rt;
 204         struct dn_route __rcu **rtp;
 205         int i;
 206         unsigned long now = jiffies;
 207         unsigned long expire = 10 * HZ;
 208
 209         for (i = 0; i <= dn_rt_hash_mask; i++) {
 210
 211                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 212                 rtp = &dn_rt_hash_table[i].chain;
 213
 214                 while ((rt = rcu_dereference_protected(*rtp,
 215                                                 lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
 216                         if (atomic_read(&rt->dst.__refcnt) ||
 217                                         (now - rt->dst.lastuse) < expire) {
 218                                 rtp = &rt->dst.dn_next;
 219                                 continue;
 220                         }
 221                         *rtp = rt->dst.dn_next;
 222                         rt->dst.dn_next = NULL;
 223                         dnrt_drop(rt);
 224                         break;
 225                 }
 226                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 227         }
 228
 229         return 0;
 230 }
 231
 232 /*
 233  * The decnet standards don't impose a particular minimum mtu, what they
 234  * do insist on is that the routing layer accepts a datagram of at least
 235  * 230 bytes long. Here we have to subtract the routing header length from
 236  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 237  * assume the worst and use a long header size.
 238  *
 239  * We update both the mtu and the advertised mss (i.e. the segment size we
 240  * advertise to the other end).
 241  */
 242 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
 243 {
 244         u32 min_mtu = 230;
 245         struct dn_dev *dn = dst->neighbour ?
 246                             rcu_dereference_raw(dst->neighbour->dev->dn_ptr) : NULL;
 247
 248         if (dn && dn->use_long == 0)
 249                 min_mtu -= 6;
 250         else
 251                 min_mtu -= 21;
 252
 253         if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
 254                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
 255                         dst_metric_set(dst, RTAX_MTU, mtu);
 256                         dst_set_expires(dst, dn_rt_mtu_expires);
 257                 }
 258                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 259                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 260                         u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
 261                         if (!existing_mss || existing_mss > mss)
 262                                 dst_metric_set(dst, RTAX_ADVMSS, mss);
 263                 }
 264         }
 265 }
 266
 267 /*
 268  * When a route has been marked obsolete. (e.g. routing cache flush)
 269  */
 270 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 271 {
 272         return NULL;
 273 }
 274
 275 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 276 {
 277         dst_release(dst);
 278         return NULL;
 279 }
 280
 281 static void dn_dst_link_failure(struct sk_buff *skb)
 282 {
 283 }
 284
 285 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
 286 {
 287         return ((fl1->fld_dst ^ fl2->fld_dst) |
 288                 (fl1->fld_src ^ fl2->fld_src) |
 289                 (fl1->mark ^ fl2->mark) |
 290                 (fl1->fld_scope ^ fl2->fld_scope) |
 291                 (fl1->oif ^ fl2->oif) |
 292                 (fl1->iif ^ fl2->iif)) == 0;
 293 }
 294
 295 static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
 296 {
 297         struct dn_route *rth;
 298         struct dn_route __rcu **rthp;
 299         unsigned long now = jiffies;
 300
 301         rthp = &dn_rt_hash_table[hash].chain;
 302
 303         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 304         while ((rth = rcu_dereference_protected(*rthp,
 305                                                 lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
 306                 if (compare_keys(&rth->fl, &rt->fl)) {
 307                         /* Put it first */
 308                         *rthp = rth->dst.dn_next;
 309                         rcu_assign_pointer(rth->dst.dn_next,
 310                                            dn_rt_hash_table[hash].chain);
 311                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 312
 313                         dst_use(&rth->dst, now);
 314                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 315
 316                         dnrt_drop(rt);
 317                         *rp = rth;
 318                         return 0;
 319                 }
 320                 rthp = &rth->dst.dn_next;
 321         }
 322
 323         rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain);
 324         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 325
 326         dst_use(&rt->dst, now);
 327         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 328         *rp = rt;
 329         return 0;
 330 }
 331
 332 static void dn_run_flush(unsigned long dummy)
 333 {
 334         int i;
 335         struct dn_route *rt, *next;
 336
 337         for (i = 0; i < dn_rt_hash_mask; i++) {
 338                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 339
 340                 if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
 341                         goto nothing_to_declare;
 342
 343                 for(; rt; rt = next) {
 344                         next = rcu_dereference_raw(rt->dst.dn_next);
 345                         RCU_INIT_POINTER(rt->dst.dn_next, NULL);
 346                         dst_free((struct dst_entry *)rt);
 347                 }
 348
 349 nothing_to_declare:
 350                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 351         }
 352 }
 353
 354 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 355
 356 void dn_rt_cache_flush(int delay)
 357 {
 358         unsigned long now = jiffies;
 359         int user_mode = !in_interrupt();
 360
 361         if (delay < 0)
 362                 delay = dn_rt_min_delay;
 363
 364         spin_lock_bh(&dn_rt_flush_lock);
 365
 366         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 367                 long tmo = (long)(dn_rt_deadline - now);
 368
 369                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 370                         tmo = 0;
 371
 372                 if (delay > tmo)
 373                         delay = tmo;
 374         }
 375
 376         if (delay <= 0) {
 377                 spin_unlock_bh(&dn_rt_flush_lock);
 378                 dn_run_flush(0);
 379                 return;
 380         }
 381
 382         if (dn_rt_deadline == 0)
 383                 dn_rt_deadline = now + dn_rt_max_delay;
 384
 385         dn_rt_flush_timer.expires = now + delay;
 386         add_timer(&dn_rt_flush_timer);
 387         spin_unlock_bh(&dn_rt_flush_lock);
 388 }
 389
 390 /**
 391  * dn_return_short - Return a short packet to its sender
 392  * @skb: The packet to return
 393  *
 394  */
 395 static int dn_return_short(struct sk_buff *skb)
 396 {
 397         struct dn_skb_cb *cb;
 398         unsigned char *ptr;
 399         __le16 *src;
 400         __le16 *dst;
 401
 402         /* Add back headers */
 403         skb_push(skb, skb->data - skb_network_header(skb));
 404
 405         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 406                 return NET_RX_DROP;
 407
 408         cb = DN_SKB_CB(skb);
 409         /* Skip packet length and point to flags */
 410         ptr = skb->data + 2;
 411         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 412
 413         dst = (__le16 *)ptr;
 414         ptr += 2;
 415         src = (__le16 *)ptr;
 416         ptr += 2;
 417         *ptr = 0; /* Zero hop count */
 418
 419         swap(*src, *dst);
 420
 421         skb->pkt_type = PACKET_OUTGOING;
 422         dn_rt_finish_output(skb, NULL, NULL);
 423         return NET_RX_SUCCESS;
 424 }
 425
 426 /**
 427  * dn_return_long - Return a long packet to its sender
 428  * @skb: The long format packet to return
 429  *
 430  */
 431 static int dn_return_long(struct sk_buff *skb)
 432 {
 433         struct dn_skb_cb *cb;
 434         unsigned char *ptr;
 435         unsigned char *src_addr, *dst_addr;
 436         unsigned char tmp[ETH_ALEN];
 437
 438         /* Add back all headers */
 439         skb_push(skb, skb->data - skb_network_header(skb));
 440
 441         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 442                 return NET_RX_DROP;
 443
 444         cb = DN_SKB_CB(skb);
 445         /* Ignore packet length and point to flags */
 446         ptr = skb->data + 2;
 447
 448         /* Skip padding */
 449         if (*ptr & DN_RT_F_PF) {
 450                 char padlen = (*ptr & ~DN_RT_F_PF);
 451                 ptr += padlen;
 452         }
 453
 454         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 455         ptr += 2;
 456         dst_addr = ptr;
 457         ptr += 8;
 458         src_addr = ptr;
 459         ptr += 6;
 460         *ptr = 0; /* Zero hop count */
 461
 462         /* Swap source and destination */
 463         memcpy(tmp, src_addr, ETH_ALEN);
 464         memcpy(src_addr, dst_addr, ETH_ALEN);
 465         memcpy(dst_addr, tmp, ETH_ALEN);
 466
 467         skb->pkt_type = PACKET_OUTGOING;
 468         dn_rt_finish_output(skb, dst_addr, src_addr);
 469         return NET_RX_SUCCESS;
 470 }
 471
 472 /**
 473  * dn_route_rx_packet - Try and find a route for an incoming packet
 474  * @skb: The packet to find a route for
 475  *
 476  * Returns: result of input function if route is found, error code otherwise
 477  */
 478 static int dn_route_rx_packet(struct sk_buff *skb)
 479 {
 480         struct dn_skb_cb *cb;
 481         int err;
 482
 483         if ((err = dn_route_input(skb)) == 0)
 484                 return dst_input(skb);
 485
 486         cb = DN_SKB_CB(skb);
 487         if (decnet_debug_level & 4) {
 488                 char *devname = skb->dev ? skb->dev->name : "???";
 489
 490                 printk(KERN_DEBUG
 491                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 492                         (int)cb->rt_flags, devname, skb->len,
 493                         le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
 494                         err, skb->pkt_type);
 495         }
 496
 497         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 498                 switch(cb->rt_flags & DN_RT_PKT_MSK) {
 499                         case DN_RT_PKT_SHORT:
 500                                 return dn_return_short(skb);
 501                         case DN_RT_PKT_LONG:
 502                                 return dn_return_long(skb);
 503                 }
 504         }
 505
 506         kfree_skb(skb);
 507         return NET_RX_DROP;
 508 }
 509
 510 static int dn_route_rx_long(struct sk_buff *skb)
 511 {
 512         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 513         unsigned char *ptr = skb->data;
 514
 515         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 516                 goto drop_it;
 517
 518         skb_pull(skb, 20);
 519         skb_reset_transport_header(skb);
 520
 521         /* Destination info */
 522         ptr += 2;
 523         cb->dst = dn_eth2dn(ptr);
 524         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 525                 goto drop_it;
 526         ptr += 6;
 527
 528
 529         /* Source info */
 530         ptr += 2;
 531         cb->src = dn_eth2dn(ptr);
 532         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 533                 goto drop_it;
 534         ptr += 6;
 535         /* Other junk */
 536         ptr++;
 537         cb->hops = *ptr++; /* Visit Count */
 538
 539         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 540                        dn_route_rx_packet);
 541
 542 drop_it:
 543         kfree_skb(skb);
 544         return NET_RX_DROP;
 545 }
 546
 547
 548
 549 static int dn_route_rx_short(struct sk_buff *skb)
 550 {
 551         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 552         unsigned char *ptr = skb->data;
 553
 554         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 555                 goto drop_it;
 556
 557         skb_pull(skb, 5);
 558         skb_reset_transport_header(skb);
 559
 560         cb->dst = *(__le16 *)ptr;
 561         ptr += 2;
 562         cb->src = *(__le16 *)ptr;
 563         ptr += 2;
 564         cb->hops = *ptr & 0x3f;
 565
 566         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 567                        dn_route_rx_packet);
 568
 569 drop_it:
 570         kfree_skb(skb);
 571         return NET_RX_DROP;
 572 }
 573
 574 static int dn_route_discard(struct sk_buff *skb)
 575 {
 576         /*
 577          * I know we drop the packet here, but thats considered success in
 578          * this case
 579          */
 580         kfree_skb(skb);
 581         return NET_RX_SUCCESS;
 582 }
 583
 584 static int dn_route_ptp_hello(struct sk_buff *skb)
 585 {
 586         dn_dev_hello(skb);
 587         dn_neigh_pointopoint_hello(skb);
 588         return NET_RX_SUCCESS;
 589 }
 590
 591 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 592 {
 593         struct dn_skb_cb *cb;
 594         unsigned char flags = 0;
 595         __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 596         struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
 597         unsigned char padlen = 0;
 598
 599         if (!net_eq(dev_net(dev), &init_net))
 600                 goto dump_it;
 601
 602         if (dn == NULL)
 603                 goto dump_it;
 604
 605         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 606                 goto out;
 607
 608         if (!pskb_may_pull(skb, 3))
 609                 goto dump_it;
 610
 611         skb_pull(skb, 2);
 612
 613         if (len > skb->len)
 614                 goto dump_it;
 615
 616         skb_trim(skb, len);
 617
 618         flags = *skb->data;
 619
 620         cb = DN_SKB_CB(skb);
 621         cb->stamp = jiffies;
 622         cb->iif = dev->ifindex;
 623
 624         /*
 625          * If we have padding, remove it.
 626          */
 627         if (flags & DN_RT_F_PF) {
 628                 padlen = flags & ~DN_RT_F_PF;
 629                 if (!pskb_may_pull(skb, padlen + 1))
 630                         goto dump_it;
 631                 skb_pull(skb, padlen);
 632                 flags = *skb->data;
 633         }
 634
 635         skb_reset_network_header(skb);
 636
 637         /*
 638          * Weed out future version DECnet
 639          */
 640         if (flags & DN_RT_F_VER)
 641                 goto dump_it;
 642
 643         cb->rt_flags = flags;
 644
 645         if (decnet_debug_level & 1)
 646                 printk(KERN_DEBUG
 647                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 648                         (int)flags, (dev) ? dev->name : "???", len, skb->len,
 649                         padlen);
 650
 651         if (flags & DN_RT_PKT_CNTL) {
 652                 if (unlikely(skb_linearize(skb)))
 653                         goto dump_it;
 654
 655                 switch(flags & DN_RT_CNTL_MSK) {
 656                         case DN_RT_PKT_INIT:
 657                                 dn_dev_init_pkt(skb);
 658                                 break;
 659                         case DN_RT_PKT_VERI:
 660                                 dn_dev_veri_pkt(skb);
 661                                 break;
 662                 }
 663
 664                 if (dn->parms.state != DN_DEV_S_RU)
 665                         goto dump_it;
 666
 667                 switch(flags & DN_RT_CNTL_MSK) {
 668                         case DN_RT_PKT_HELO:
 669                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 670                                                skb, skb->dev, NULL,
 671                                                dn_route_ptp_hello);
 672
 673                         case DN_RT_PKT_L1RT:
 674                         case DN_RT_PKT_L2RT:
 675                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
 676                                                skb, skb->dev, NULL,
 677                                                dn_route_discard);
 678                         case DN_RT_PKT_ERTH:
 679                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 680                                                skb, skb->dev, NULL,
 681                                                dn_neigh_router_hello);
 682
 683                         case DN_RT_PKT_EEDH:
 684                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 685                                                skb, skb->dev, NULL,
 686                                                dn_neigh_endnode_hello);
 687                 }
 688         } else {
 689                 if (dn->parms.state != DN_DEV_S_RU)
 690                         goto dump_it;
 691
 692                 skb_pull(skb, 1); /* Pull flags */
 693
 694                 switch(flags & DN_RT_PKT_MSK) {
 695                         case DN_RT_PKT_LONG:
 696                                 return dn_route_rx_long(skb);
 697                         case DN_RT_PKT_SHORT:
 698                                 return dn_route_rx_short(skb);
 699                 }
 700         }
 701
 702 dump_it:
 703         kfree_skb(skb);
 704 out:
 705         return NET_RX_DROP;
 706 }
 707
 708 static int dn_output(struct sk_buff *skb)
 709 {
 710         struct dst_entry *dst = skb_dst(skb);
 711         struct dn_route *rt = (struct dn_route *)dst;
 712         struct net_device *dev = dst->dev;
 713         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 714         struct neighbour *neigh;
 715
 716         int err = -EINVAL;
 717
 718         if ((neigh = dst->neighbour) == NULL)
 719                 goto error;
 720
 721         skb->dev = dev;
 722
 723         cb->src = rt->rt_saddr;
 724         cb->dst = rt->rt_daddr;
 725
 726         /*
 727          * Always set the Intra-Ethernet bit on all outgoing packets
 728          * originated on this node. Only valid flag from upper layers
 729          * is return-to-sender-requested. Set hop count to 0 too.
 730          */
 731         cb->rt_flags &= ~DN_RT_F_RQR;
 732         cb->rt_flags |= DN_RT_F_IE;
 733         cb->hops = 0;
 734
 735         return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, skb, NULL, dev,
 736                        neigh->output);
 737
 738 error:
 739         if (net_ratelimit())
 740                 printk(KERN_DEBUG "dn_output: This should not happen\n");
 741
 742         kfree_skb(skb);
 743
 744         return err;
 745 }
 746
 747 static int dn_forward(struct sk_buff *skb)
 748 {
 749         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 750         struct dst_entry *dst = skb_dst(skb);
 751         struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
 752         struct dn_route *rt;
 753         struct neighbour *neigh = dst->neighbour;
 754         int header_len;
 755 #ifdef CONFIG_NETFILTER
 756         struct net_device *dev = skb->dev;
 757 #endif
 758
 759         if (skb->pkt_type != PACKET_HOST)
 760                 goto drop;
 761
 762         /* Ensure that we have enough space for headers */
 763         rt = (struct dn_route *)skb_dst(skb);
 764         header_len = dn_db->use_long ? 21 : 6;
 765         if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
 766                 goto drop;
 767
 768         /*
 769          * Hop count exceeded.
 770          */
 771         if (++cb->hops > 30)
 772                 goto drop;
 773
 774         skb->dev = rt->dst.dev;
 775
 776         /*
 777          * If packet goes out same interface it came in on, then set
 778          * the Intra-Ethernet bit. This has no effect for short
 779          * packets, so we don't need to test for them here.
 780          */
 781         cb->rt_flags &= ~DN_RT_F_IE;
 782         if (rt->rt_flags & RTCF_DOREDIRECT)
 783                 cb->rt_flags |= DN_RT_F_IE;
 784
 785         return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, skb, dev, skb->dev,
 786                        neigh->output);
 787
 788 drop:
 789         kfree_skb(skb);
 790         return NET_RX_DROP;
 791 }
 792
 793 /*
 794  * Used to catch bugs. This should never normally get
 795  * called.
 796  */
 797 static int dn_rt_bug(struct sk_buff *skb)
 798 {
 799         if (net_ratelimit()) {
 800                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 801
 802                 printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
 803                                 le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 804         }
 805
 806         kfree_skb(skb);
 807
 808         return NET_RX_DROP;
 809 }
 810
 811 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
 812 {
 813         return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
 814 }
 815
 816 static unsigned int dn_dst_default_mtu(const struct dst_entry *dst)
 817 {
 818         return dst->dev->mtu;
 819 }
 820
 821 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 822 {
 823         struct dn_fib_info *fi = res->fi;
 824         struct net_device *dev = rt->dst.dev;
 825         unsigned int mss_metric;
 826         struct neighbour *n;
 827
 828         if (fi) {
 829                 if (DN_FIB_RES_GW(*res) &&
 830                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 831                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 832                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
 833         }
 834         rt->rt_type = res->type;
 835
 836         if (dev != NULL && rt->dst.neighbour == NULL) {
 837                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 838                 if (IS_ERR(n))
 839                         return PTR_ERR(n);
 840                 rt->dst.neighbour = n;
 841         }
 842
 843         if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
 844                 dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
 845         mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
 846         if (mss_metric) {
 847                 unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
 848                 if (mss_metric > mss)
 849                         dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
 850         }
 851         return 0;
 852 }
 853
 854 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 855 {
 856         __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 857         int match = 16;
 858         while(tmp) {
 859                 tmp >>= 1;
 860                 match--;
 861         }
 862         return match;
 863 }
 864
 865 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 866 {
 867         __le16 saddr = 0;
 868         struct dn_dev *dn_db;
 869         struct dn_ifaddr *ifa;
 870         int best_match = 0;
 871         int ret;
 872
 873         rcu_read_lock();
 874         dn_db = rcu_dereference(dev->dn_ptr);
 875         for (ifa = rcu_dereference(dn_db->ifa_list);
 876              ifa != NULL;
 877              ifa = rcu_dereference(ifa->ifa_next)) {
 878                 if (ifa->ifa_scope > scope)
 879                         continue;
 880                 if (!daddr) {
 881                         saddr = ifa->ifa_local;
 882                         break;
 883                 }
 884                 ret = dn_match_addr(daddr, ifa->ifa_local);
 885                 if (ret > best_match)
 886                         saddr = ifa->ifa_local;
 887                 if (best_match == 0)
 888                         saddr = ifa->ifa_local;
 889         }
 890         rcu_read_unlock();
 891
 892         return saddr;
 893 }
 894
 895 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 896 {
 897         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 898 }
 899
 900 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 901 {
 902         __le16 mask = dnet_make_mask(res->prefixlen);
 903         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 904 }
 905
 906 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
 907 {
 908         struct flowi fl = { .fld_dst = oldflp->fld_dst,
 909                             .fld_src = oldflp->fld_src,
 910                             .fld_scope = RT_SCOPE_UNIVERSE,
 911                             .mark = oldflp->mark,
 912                             .iif = init_net.loopback_dev->ifindex,
 913                             .oif = oldflp->oif };
 914         struct dn_route *rt = NULL;
 915         struct net_device *dev_out = NULL, *dev;
 916         struct neighbour *neigh = NULL;
 917         unsigned hash;
 918         unsigned flags = 0;
 919         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 920         int err;
 921         int free_res = 0;
 922         __le16 gateway = 0;
 923
 924         if (decnet_debug_level & 16)
 925                 printk(KERN_DEBUG
 926                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 927                        " iif=%d oif=%d\n", le16_to_cpu(oldflp->fld_dst),
 928                        le16_to_cpu(oldflp->fld_src),
 929                        oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);
 930
 931         /* If we have an output interface, verify its a DECnet device */
 932         if (oldflp->oif) {
 933                 dev_out = dev_get_by_index(&init_net, oldflp->oif);
 934                 err = -ENODEV;
 935                 if (dev_out && dev_out->dn_ptr == NULL) {
 936                         dev_put(dev_out);
 937                         dev_out = NULL;
 938                 }
 939                 if (dev_out == NULL)
 940                         goto out;
 941         }
 942
 943         /* If we have a source address, verify that its a local address */
 944         if (oldflp->fld_src) {
 945                 err = -EADDRNOTAVAIL;
 946
 947                 if (dev_out) {
 948                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
 949                                 goto source_ok;
 950                         dev_put(dev_out);
 951                         goto out;
 952                 }
 953                 rcu_read_lock();
 954                 for_each_netdev_rcu(&init_net, dev) {
 955                         if (!dev->dn_ptr)
 956                                 continue;
 957                         if (!dn_dev_islocal(dev, oldflp->fld_src))
 958                                 continue;
 959                         if ((dev->flags & IFF_LOOPBACK) &&
 960                             oldflp->fld_dst &&
 961                             !dn_dev_islocal(dev, oldflp->fld_dst))
 962                                 continue;
 963
 964                         dev_out = dev;
 965                         break;
 966                 }
 967                 rcu_read_unlock();
 968                 if (dev_out == NULL)
 969                         goto out;
 970                 dev_hold(dev_out);
 971 source_ok:
 972                 ;
 973         }
 974
 975         /* No destination? Assume its local */
 976         if (!fl.fld_dst) {
 977                 fl.fld_dst = fl.fld_src;
 978
 979                 err = -EADDRNOTAVAIL;
 980                 if (dev_out)
 981                         dev_put(dev_out);
 982                 dev_out = init_net.loopback_dev;
 983                 dev_hold(dev_out);
 984                 if (!fl.fld_dst) {
 985                         fl.fld_dst =
 986                         fl.fld_src = dnet_select_source(dev_out, 0,
 987                                                        RT_SCOPE_HOST);
 988                         if (!fl.fld_dst)
 989                                 goto out;
 990                 }
 991                 fl.oif = init_net.loopback_dev->ifindex;
 992                 res.type = RTN_LOCAL;
 993                 goto make_route;
 994         }
 995
 996         if (decnet_debug_level & 16)
 997                 printk(KERN_DEBUG
 998                        "dn_route_output_slow: initial checks complete."
 999                        " dst=%o4x src=%04x oif=%d try_hard=%d\n",
1000                        le16_to_cpu(fl.fld_dst), le16_to_cpu(fl.fld_src),
1001                        fl.oif, try_hard);
1002
1003         /*
1004          * N.B. If the kernel is compiled without router support then
1005          * dn_fib_lookup() will evaluate to non-zero so this if () block
1006          * will always be executed.
1007          */
1008         err = -ESRCH;
1009         if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
1010                 struct dn_dev *dn_db;
1011                 if (err != -ESRCH)
1012                         goto out;
1013                 /*
1014                  * Here the fallback is basically the standard algorithm for
1015                  * routing in endnodes which is described in the DECnet routing
1016                  * docs
1017                  *
1018                  * If we are not trying hard, look in neighbour cache.
1019                  * The result is tested to ensure that if a specific output
1020                  * device/source address was requested, then we honour that
1021                  * here
1022                  */
1023                 if (!try_hard) {
1024                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fl.fld_dst);
1025                         if (neigh) {
1026                                 if ((oldflp->oif &&
1027                                     (neigh->dev->ifindex != oldflp->oif)) ||
1028                                     (oldflp->fld_src &&
1029                                     (!dn_dev_islocal(neigh->dev,
1030                                                       oldflp->fld_src)))) {
1031                                         neigh_release(neigh);
1032                                         neigh = NULL;
1033                                 } else {
1034                                         if (dev_out)
1035                                                 dev_put(dev_out);
1036                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
1037                                                 dev_out = init_net.loopback_dev;
1038                                                 res.type = RTN_LOCAL;
1039                                         } else {
1040                                                 dev_out = neigh->dev;
1041                                         }
1042                                         dev_hold(dev_out);
1043                                         goto select_source;
1044                                 }
1045                         }
1046                 }
1047
1048                 /* Not there? Perhaps its a local address */
1049                 if (dev_out == NULL)
1050                         dev_out = dn_dev_get_default();
1051                 err = -ENODEV;
1052                 if (dev_out == NULL)
1053                         goto out;
1054                 dn_db = rcu_dereference_raw(dev_out->dn_ptr);
1055                 /* Possible improvement - check all devices for local addr */
1056                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1057                         dev_put(dev_out);
1058                         dev_out = init_net.loopback_dev;
1059                         dev_hold(dev_out);
1060                         res.type = RTN_LOCAL;
1061                         goto select_source;
1062                 }
1063                 /* Not local either.... try sending it to the default router */
1064                 neigh = neigh_clone(dn_db->router);
1065                 BUG_ON(neigh && neigh->dev != dev_out);
1066
1067                 /* Ok then, we assume its directly connected and move on */
1068 select_source:
1069                 if (neigh)
1070                         gateway = ((struct dn_neigh *)neigh)->addr;
1071                 if (gateway == 0)
1072                         gateway = fl.fld_dst;
1073                 if (fl.fld_src == 0) {
1074                         fl.fld_src = dnet_select_source(dev_out, gateway,
1075                                                          res.type == RTN_LOCAL ?
1076                                                          RT_SCOPE_HOST :
1077                                                          RT_SCOPE_LINK);
1078                         if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1079                                 goto e_addr;
1080                 }
1081                 fl.oif = dev_out->ifindex;
1082                 goto make_route;
1083         }
1084         free_res = 1;
1085
1086         if (res.type == RTN_NAT)
1087                 goto e_inval;
1088
1089         if (res.type == RTN_LOCAL) {
1090                 if (!fl.fld_src)
1091                         fl.fld_src = fl.fld_dst;
1092                 if (dev_out)
1093                         dev_put(dev_out);
1094                 dev_out = init_net.loopback_dev;
1095                 dev_hold(dev_out);
1096                 fl.oif = dev_out->ifindex;
1097                 if (res.fi)
1098                         dn_fib_info_put(res.fi);
1099                 res.fi = NULL;
1100                 goto make_route;
1101         }
1102
1103         if (res.fi->fib_nhs > 1 && fl.oif == 0)
1104                 dn_fib_select_multipath(&fl, &res);
1105
1106         /*
1107          * We could add some logic to deal with default routes here and
1108          * get rid of some of the special casing above.
1109          */
1110
1111         if (!fl.fld_src)
1112                 fl.fld_src = DN_FIB_RES_PREFSRC(res);
1113
1114         if (dev_out)
1115                 dev_put(dev_out);
1116         dev_out = DN_FIB_RES_DEV(res);
1117         dev_hold(dev_out);
1118         fl.oif = dev_out->ifindex;
1119         gateway = DN_FIB_RES_GW(res);
1120
1121 make_route:
1122         if (dev_out->flags & IFF_LOOPBACK)
1123                 flags |= RTCF_LOCAL;
1124
1125         rt = dst_alloc(&dn_dst_ops, 0);
1126         if (rt == NULL)
1127                 goto e_nobufs;
1128
1129         atomic_set(&rt->dst.__refcnt, 1);
1130         rt->dst.flags   = DST_HOST;
1131
1132         rt->fl.fld_src    = oldflp->fld_src;
1133         rt->fl.fld_dst    = oldflp->fld_dst;
1134         rt->fl.oif        = oldflp->oif;
1135         rt->fl.iif        = 0;
1136         rt->fl.mark       = oldflp->mark;
1137
1138         rt->rt_saddr      = fl.fld_src;
1139         rt->rt_daddr      = fl.fld_dst;
1140         rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1141         rt->rt_local_src  = fl.fld_src;
1142
1143         rt->rt_dst_map    = fl.fld_dst;
1144         rt->rt_src_map    = fl.fld_src;
1145
1146         rt->dst.dev = dev_out;
1147         dev_hold(dev_out);
1148         rt->dst.neighbour = neigh;
1149         neigh = NULL;
1150
1151         rt->dst.lastuse = jiffies;
1152         rt->dst.output  = dn_output;
1153         rt->dst.input   = dn_rt_bug;
1154         rt->rt_flags      = flags;
1155         if (flags & RTCF_LOCAL)
1156                 rt->dst.input = dn_nsp_rx;
1157
1158         err = dn_rt_set_next_hop(rt, &res);
1159         if (err)
1160                 goto e_neighbour;
1161
1162         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1163         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1164
1165 done:
1166         if (neigh)
1167                 neigh_release(neigh);
1168         if (free_res)
1169                 dn_fib_res_put(&res);
1170         if (dev_out)
1171                 dev_put(dev_out);
1172 out:
1173         return err;
1174
1175 e_addr:
1176         err = -EADDRNOTAVAIL;
1177         goto done;
1178 e_inval:
1179         err = -EINVAL;
1180         goto done;
1181 e_nobufs:
1182         err = -ENOBUFS;
1183         goto done;
1184 e_neighbour:
1185         dst_free(&rt->dst);
1186         goto e_nobufs;
1187 }
1188
1189
1190 /*
1191  * N.B. The flags may be moved into the flowi at some future stage.
1192  */
1193 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1194 {
1195         unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1196         struct dn_route *rt = NULL;
1197
1198         if (!(flags & MSG_TRYHARD)) {
1199                 rcu_read_lock_bh();
1200                 for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1201                         rt = rcu_dereference_bh(rt->dst.dn_next)) {
1202                         if ((flp->fld_dst == rt->fl.fld_dst) &&
1203                             (flp->fld_src == rt->fl.fld_src) &&
1204                             (flp->mark == rt->fl.mark) &&
1205                             dn_is_output_route(rt) &&
1206                             (rt->fl.oif == flp->oif)) {
1207                                 dst_use(&rt->dst, jiffies);
1208                                 rcu_read_unlock_bh();
1209                                 *pprt = &rt->dst;
1210                                 return 0;
1211                         }
1212                 }
1213                 rcu_read_unlock_bh();
1214         }
1215
1216         return dn_route_output_slow(pprt, flp, flags);
1217 }
1218
1219 static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
1220 {
1221         int err;
1222
1223         err = __dn_route_output_key(pprt, flp, flags);
1224         if (err == 0 && flp->proto) {
1225                 err = xfrm_lookup(&init_net, pprt, flp, NULL, 0);
1226         }
1227         return err;
1228 }
1229
1230 int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
1231 {
1232         int err;
1233
1234         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1235         if (err == 0 && fl->proto) {
1236                 err = xfrm_lookup(&init_net, pprt, fl, sk,
1237                                  (flags & MSG_DONTWAIT) ? 0 : XFRM_LOOKUP_WAIT);
1238         }
1239         return err;
1240 }
1241
1242 static int dn_route_input_slow(struct sk_buff *skb)
1243 {
1244         struct dn_route *rt = NULL;
1245         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1246         struct net_device *in_dev = skb->dev;
1247         struct net_device *out_dev = NULL;
1248         struct dn_dev *dn_db;
1249         struct neighbour *neigh = NULL;
1250         unsigned hash;
1251         int flags = 0;
1252         __le16 gateway = 0;
1253         __le16 local_src = 0;
1254         struct flowi fl = { .fld_dst = cb->dst,
1255                             .fld_src = cb->src,
1256                             .fld_scope = RT_SCOPE_UNIVERSE,
1257                             .mark = skb->mark,
1258                             .iif = skb->dev->ifindex };
1259         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1260         int err = -EINVAL;
1261         int free_res = 0;
1262
1263         dev_hold(in_dev);
1264
1265         if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
1266                 goto out;
1267
1268         /* Zero source addresses are not allowed */
1269         if (fl.fld_src == 0)
1270                 goto out;
1271
1272         /*
1273          * In this case we've just received a packet from a source
1274          * outside ourselves pretending to come from us. We don't
1275          * allow it any further to prevent routing loops, spoofing and
1276          * other nasties. Loopback packets already have the dst attached
1277          * so this only affects packets which have originated elsewhere.
1278          */
1279         err  = -ENOTUNIQ;
1280         if (dn_dev_islocal(in_dev, cb->src))
1281                 goto out;
1282
1283         err = dn_fib_lookup(&fl, &res);
1284         if (err) {
1285                 if (err != -ESRCH)
1286                         goto out;
1287                 /*
1288                  * Is the destination us ?
1289                  */
1290                 if (!dn_dev_islocal(in_dev, cb->dst))
1291                         goto e_inval;
1292
1293                 res.type = RTN_LOCAL;
1294         } else {
1295                 __le16 src_map = fl.fld_src;
1296                 free_res = 1;
1297
1298                 out_dev = DN_FIB_RES_DEV(res);
1299                 if (out_dev == NULL) {
1300                         if (net_ratelimit())
1301                                 printk(KERN_CRIT "Bug in dn_route_input_slow() "
1302                                                  "No output device\n");
1303                         goto e_inval;
1304                 }
1305                 dev_hold(out_dev);
1306
1307                 if (res.r)
1308                         src_map = fl.fld_src; /* no NAT support for now */
1309
1310                 gateway = DN_FIB_RES_GW(res);
1311                 if (res.type == RTN_NAT) {
1312                         fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1313                         dn_fib_res_put(&res);
1314                         free_res = 0;
1315                         if (dn_fib_lookup(&fl, &res))
1316                                 goto e_inval;
1317                         free_res = 1;
1318                         if (res.type != RTN_UNICAST)
1319                                 goto e_inval;
1320                         flags |= RTCF_DNAT;
1321                         gateway = fl.fld_dst;
1322                 }
1323                 fl.fld_src = src_map;
1324         }
1325
1326         switch(res.type) {
1327         case RTN_UNICAST:
1328                 /*
1329                  * Forwarding check here, we only check for forwarding
1330                  * being turned off, if you want to only forward intra
1331                  * area, its up to you to set the routing tables up
1332                  * correctly.
1333                  */
1334                 if (dn_db->parms.forwarding == 0)
1335                         goto e_inval;
1336
1337                 if (res.fi->fib_nhs > 1 && fl.oif == 0)
1338                         dn_fib_select_multipath(&fl, &res);
1339
1340                 /*
1341                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1342                  * flag as a hint to set the intra-ethernet bit when
1343                  * forwarding. If we've got NAT in operation, we don't do
1344                  * this optimisation.
1345                  */
1346                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1347                         flags |= RTCF_DOREDIRECT;
1348
1349                 local_src = DN_FIB_RES_PREFSRC(res);
1350
1351         case RTN_BLACKHOLE:
1352         case RTN_UNREACHABLE:
1353                 break;
1354         case RTN_LOCAL:
1355                 flags |= RTCF_LOCAL;
1356                 fl.fld_src = cb->dst;
1357                 fl.fld_dst = cb->src;
1358
1359                 /* Routing tables gave us a gateway */
1360                 if (gateway)
1361                         goto make_route;
1362
1363                 /* Packet was intra-ethernet, so we know its on-link */
1364                 if (cb->rt_flags & DN_RT_F_IE) {
1365                         gateway = cb->src;
1366                         flags |= RTCF_DIRECTSRC;
1367                         goto make_route;
1368                 }
1369
1370                 /* Use the default router if there is one */
1371                 neigh = neigh_clone(dn_db->router);
1372                 if (neigh) {
1373                         gateway = ((struct dn_neigh *)neigh)->addr;
1374                         goto make_route;
1375                 }
1376
1377                 /* Close eyes and pray */
1378                 gateway = cb->src;
1379                 flags |= RTCF_DIRECTSRC;
1380                 goto make_route;
1381         default:
1382                 goto e_inval;
1383         }
1384
1385 make_route:
1386         rt = dst_alloc(&dn_dst_ops, 0);
1387         if (rt == NULL)
1388                 goto e_nobufs;
1389
1390         rt->rt_saddr      = fl.fld_src;
1391         rt->rt_daddr      = fl.fld_dst;
1392         rt->rt_gateway    = fl.fld_dst;
1393         if (gateway)
1394                 rt->rt_gateway = gateway;
1395         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1396
1397         rt->rt_dst_map    = fl.fld_dst;
1398         rt->rt_src_map    = fl.fld_src;
1399
1400         rt->fl.fld_src    = cb->src;
1401         rt->fl.fld_dst    = cb->dst;
1402         rt->fl.oif        = 0;
1403         rt->fl.iif        = in_dev->ifindex;
1404         rt->fl.mark       = fl.mark;
1405
1406         rt->dst.flags = DST_HOST;
1407         rt->dst.neighbour = neigh;
1408         rt->dst.dev = out_dev;
1409         rt->dst.lastuse = jiffies;
1410         rt->dst.output = dn_rt_bug;
1411         switch(res.type) {
1412                 case RTN_UNICAST:
1413                         rt->dst.input = dn_forward;
1414                         break;
1415                 case RTN_LOCAL:
1416                         rt->dst.output = dn_output;
1417                         rt->dst.input = dn_nsp_rx;
1418                         rt->dst.dev = in_dev;
1419                         flags |= RTCF_LOCAL;
1420                         break;
1421                 default:
1422                 case RTN_UNREACHABLE:
1423                 case RTN_BLACKHOLE:
1424                         rt->dst.input = dst_discard;
1425         }
1426         rt->rt_flags = flags;
1427         if (rt->dst.dev)
1428                 dev_hold(rt->dst.dev);
1429
1430         err = dn_rt_set_next_hop(rt, &res);
1431         if (err)
1432                 goto e_neighbour;
1433
1434         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1435         dn_insert_route(rt, hash, &rt);
1436         skb_dst_set(skb, &rt->dst);
1437
1438 done:
1439         if (neigh)
1440                 neigh_release(neigh);
1441         if (free_res)
1442                 dn_fib_res_put(&res);
1443         dev_put(in_dev);
1444         if (out_dev)
1445                 dev_put(out_dev);
1446 out:
1447         return err;
1448
1449 e_inval:
1450         err = -EINVAL;
1451         goto done;
1452
1453 e_nobufs:
1454         err = -ENOBUFS;
1455         goto done;
1456
1457 e_neighbour:
1458         dst_free(&rt->dst);
1459         goto done;
1460 }
1461
1462 static int dn_route_input(struct sk_buff *skb)
1463 {
1464         struct dn_route *rt;
1465         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1466         unsigned hash = dn_hash(cb->src, cb->dst);
1467
1468         if (skb_dst(skb))
1469                 return 0;
1470
1471         rcu_read_lock();
1472         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1473             rt = rcu_dereference(rt->dst.dn_next)) {
1474                 if ((rt->fl.fld_src == cb->src) &&
1475                     (rt->fl.fld_dst == cb->dst) &&
1476                     (rt->fl.oif == 0) &&
1477                     (rt->fl.mark == skb->mark) &&
1478                     (rt->fl.iif == cb->iif)) {
1479                         dst_use(&rt->dst, jiffies);
1480                         rcu_read_unlock();
1481                         skb_dst_set(skb, (struct dst_entry *)rt);
1482                         return 0;
1483                 }
1484         }
1485         rcu_read_unlock();
1486
1487         return dn_route_input_slow(skb);
1488 }
1489
1490 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1491                            int event, int nowait, unsigned int flags)
1492 {
1493         struct dn_route *rt = (struct dn_route *)skb_dst(skb);
1494         struct rtmsg *r;
1495         struct nlmsghdr *nlh;
1496         unsigned char *b = skb_tail_pointer(skb);
1497         long expires;
1498
1499         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1500         r = NLMSG_DATA(nlh);
1501         r->rtm_family = AF_DECnet;
1502         r->rtm_dst_len = 16;
1503         r->rtm_src_len = 0;
1504         r->rtm_tos = 0;
1505         r->rtm_table = RT_TABLE_MAIN;
1506         RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
1507         r->rtm_type = rt->rt_type;
1508         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1509         r->rtm_scope = RT_SCOPE_UNIVERSE;
1510         r->rtm_protocol = RTPROT_UNSPEC;
1511         if (rt->rt_flags & RTCF_NOTIFY)
1512                 r->rtm_flags |= RTM_F_NOTIFY;
1513         RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1514         if (rt->fl.fld_src) {
1515                 r->rtm_src_len = 16;
1516                 RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1517         }
1518         if (rt->dst.dev)
1519                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->dst.dev->ifindex);
1520         /*
1521          * Note to self - change this if input routes reverse direction when
1522          * they deal only with inputs and not with replies like they do
1523          * currently.
1524          */
1525         RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1526         if (rt->rt_daddr != rt->rt_gateway)
1527                 RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1528         if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
1529                 goto rtattr_failure;
1530         expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
1531         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, 0, 0, expires,
1532                                rt->dst.error) < 0)
1533                 goto rtattr_failure;
1534         if (dn_is_input_route(rt))
1535                 RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1536
1537         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1538         return skb->len;
1539
1540 nlmsg_failure:
1541 rtattr_failure:
1542         nlmsg_trim(skb, b);
1543         return -1;
1544 }
1545
1546 /*
1547  * This is called by both endnodes and routers now.
1548  */
1549 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1550 {
1551         struct net *net = sock_net(in_skb->sk);
1552         struct rtattr **rta = arg;
1553         struct rtmsg *rtm = NLMSG_DATA(nlh);
1554         struct dn_route *rt = NULL;
1555         struct dn_skb_cb *cb;
1556         int err;
1557         struct sk_buff *skb;
1558         struct flowi fl;
1559
1560         if (!net_eq(net, &init_net))
1561                 return -EINVAL;
1562
1563         memset(&fl, 0, sizeof(fl));
1564         fl.proto = DNPROTO_NSP;
1565
1566         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1567         if (skb == NULL)
1568                 return -ENOBUFS;
1569         skb_reset_mac_header(skb);
1570         cb = DN_SKB_CB(skb);
1571
1572         if (rta[RTA_SRC-1])
1573                 memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1574         if (rta[RTA_DST-1])
1575                 memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1576         if (rta[RTA_IIF-1])
1577                 memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1578
1579         if (fl.iif) {
1580                 struct net_device *dev;
1581                 if ((dev = dev_get_by_index(&init_net, fl.iif)) == NULL) {
1582                         kfree_skb(skb);
1583                         return -ENODEV;
1584                 }
1585                 if (!dev->dn_ptr) {
1586                         dev_put(dev);
1587                         kfree_skb(skb);
1588                         return -ENODEV;
1589                 }
1590                 skb->protocol = htons(ETH_P_DNA_RT);
1591                 skb->dev = dev;
1592                 cb->src = fl.fld_src;
1593                 cb->dst = fl.fld_dst;
1594                 local_bh_disable();
1595                 err = dn_route_input(skb);
1596                 local_bh_enable();
1597                 memset(cb, 0, sizeof(struct dn_skb_cb));
1598                 rt = (struct dn_route *)skb_dst(skb);
1599                 if (!err && -rt->dst.error)
1600                         err = rt->dst.error;
1601         } else {
1602                 int oif = 0;
1603                 if (rta[RTA_OIF - 1])
1604                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1605                 fl.oif = oif;
1606                 err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1607         }
1608
1609         if (skb->dev)
1610                 dev_put(skb->dev);
1611         skb->dev = NULL;
1612         if (err)
1613                 goto out_free;
1614         skb_dst_set(skb, &rt->dst);
1615         if (rtm->rtm_flags & RTM_F_NOTIFY)
1616                 rt->rt_flags |= RTCF_NOTIFY;
1617
1618         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1619
1620         if (err == 0)
1621                 goto out_free;
1622         if (err < 0) {
1623                 err = -EMSGSIZE;
1624                 goto out_free;
1625         }
1626
1627         return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
1628
1629 out_free:
1630         kfree_skb(skb);
1631         return err;
1632 }
1633
1634 /*
1635  * For routers, this is called from dn_fib_dump, but for endnodes its
1636  * called directly from the rtnetlink dispatch table.
1637  */
1638 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1639 {
1640         struct net *net = sock_net(skb->sk);
1641         struct dn_route *rt;
1642         int h, s_h;
1643         int idx, s_idx;
1644
1645         if (!net_eq(net, &init_net))
1646                 return 0;
1647
1648         if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1649                 return -EINVAL;
1650         if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1651                 return 0;
1652
1653         s_h = cb->args[0];
1654         s_idx = idx = cb->args[1];
1655         for(h = 0; h <= dn_rt_hash_mask; h++) {
1656                 if (h < s_h)
1657                         continue;
1658                 if (h > s_h)
1659                         s_idx = 0;
1660                 rcu_read_lock_bh();
1661                 for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1662                         rt;
1663                         rt = rcu_dereference_bh(rt->dst.dn_next), idx++) {
1664                         if (idx < s_idx)
1665                                 continue;
1666                         skb_dst_set(skb, dst_clone(&rt->dst));
1667                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1668                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1669                                         1, NLM_F_MULTI) <= 0) {
1670                                 skb_dst_drop(skb);
1671                                 rcu_read_unlock_bh();
1672                                 goto done;
1673                         }
1674                         skb_dst_drop(skb);
1675                 }
1676                 rcu_read_unlock_bh();
1677         }
1678
1679 done:
1680         cb->args[0] = h;
1681         cb->args[1] = idx;
1682         return skb->len;
1683 }
1684
1685 #ifdef CONFIG_PROC_FS
1686 struct dn_rt_cache_iter_state {
1687         int bucket;
1688 };
1689
1690 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1691 {
1692         struct dn_route *rt = NULL;
1693         struct dn_rt_cache_iter_state *s = seq->private;
1694
1695         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1696                 rcu_read_lock_bh();
1697                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1698                 if (rt)
1699                         break;
1700                 rcu_read_unlock_bh();
1701         }
1702         return rt;
1703 }
1704
1705 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1706 {
1707         struct dn_rt_cache_iter_state *s = seq->private;
1708
1709         rt = rcu_dereference_bh(rt->dst.dn_next);
1710         while (!rt) {
1711                 rcu_read_unlock_bh();
1712                 if (--s->bucket < 0)
1713                         break;
1714                 rcu_read_lock_bh();
1715                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1716         }
1717         return rt;
1718 }
1719
1720 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1721 {
1722         struct dn_route *rt = dn_rt_cache_get_first(seq);
1723
1724         if (rt) {
1725                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1726                         --*pos;
1727         }
1728         return *pos ? NULL : rt;
1729 }
1730
1731 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1732 {
1733         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1734         ++*pos;
1735         return rt;
1736 }
1737
1738 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1739 {
1740         if (v)
1741                 rcu_read_unlock_bh();
1742 }
1743
1744 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1745 {
1746         struct dn_route *rt = v;
1747         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1748
1749         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1750                         rt->dst.dev ? rt->dst.dev->name : "*",
1751                         dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1752                         dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1753                         atomic_read(&rt->dst.__refcnt),
1754                         rt->dst.__use,
1755                         (int) dst_metric(&rt->dst, RTAX_RTT));
1756         return 0;
1757 }
1758
1759 static const struct seq_operations dn_rt_cache_seq_ops = {
1760         .start  = dn_rt_cache_seq_start,
1761         .next   = dn_rt_cache_seq_next,
1762         .stop   = dn_rt_cache_seq_stop,
1763         .show   = dn_rt_cache_seq_show,
1764 };
1765
1766 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1767 {
1768         return seq_open_private(file, &dn_rt_cache_seq_ops,
1769                         sizeof(struct dn_rt_cache_iter_state));
1770 }
1771
1772 static const struct file_operations dn_rt_cache_seq_fops = {
1773         .owner   = THIS_MODULE,
1774         .open    = dn_rt_cache_seq_open,
1775         .read    = seq_read,
1776         .llseek  = seq_lseek,
1777         .release = seq_release_private,
1778 };
1779
1780 #endif /* CONFIG_PROC_FS */
1781
1782 void __init dn_route_init(void)
1783 {
1784         int i, goal, order;
1785
1786         dn_dst_ops.kmem_cachep =
1787                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1788                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1789         dst_entries_init(&dn_dst_ops);
1790         setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1791         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1792         add_timer(&dn_route_timer);
1793
1794         goal = totalram_pages >> (26 - PAGE_SHIFT);
1795
1796         for(order = 0; (1UL << order) < goal; order++)
1797                 /* NOTHING */;
1798
1799         /*
1800          * Only want 1024 entries max, since the table is very, very unlikely
1801          * to be larger than that.
1802          */
1803         while(order && ((((1UL << order) * PAGE_SIZE) /
1804                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1805                 order--;
1806
1807         do {
1808                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1809                         sizeof(struct dn_rt_hash_bucket);
1810                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1811                         dn_rt_hash_mask--;
1812                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1813                         __get_free_pages(GFP_ATOMIC, order);
1814         } while (dn_rt_hash_table == NULL && --order > 0);
1815
1816         if (!dn_rt_hash_table)
1817                 panic("Failed to allocate DECnet route cache hash table\n");
1818
1819         printk(KERN_INFO
1820                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1821                 dn_rt_hash_mask,
1822                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1823
1824         dn_rt_hash_mask--;
1825         for(i = 0; i <= dn_rt_hash_mask; i++) {
1826                 spin_lock_init(&dn_rt_hash_table[i].lock);
1827                 dn_rt_hash_table[i].chain = NULL;
1828         }
1829
1830         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1831
1832         proc_net_fops_create(&init_net, "decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1833
1834 #ifdef CONFIG_DECNET_ROUTER
1835         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute, dn_fib_dump);
1836 #else
1837         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1838                       dn_cache_dump);
1839 #endif
1840 }
1841
1842 void __exit dn_route_cleanup(void)
1843 {
1844         del_timer(&dn_route_timer);
1845         dn_run_flush(0);
1846
1847         proc_net_remove(&init_net, "decnet_cache");
1848         dst_entries_destroy(&dn_dst_ops);
1849 }
1850