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 <net/sock.h>
  70 #include <linux/mm.h>
  71 #include <linux/proc_fs.h>
  72 #include <linux/seq_file.h>
  73 #include <linux/init.h>
  74 #include <linux/rtnetlink.h>
  75 #include <linux/string.h>
  76 #include <linux/netfilter_decnet.h>
  77 #include <linux/rcupdate.h>
  78 #include <linux/times.h>
  79 #include <asm/errno.h>
  80 #include <net/neighbour.h>
  81 #include <net/dst.h>
  82 #include <net/flow.h>
  83 #include <net/fib_rules.h>
  84 #include <net/dn.h>
  85 #include <net/dn_dev.h>
  86 #include <net/dn_nsp.h>
  87 #include <net/dn_route.h>
  88 #include <net/dn_neigh.h>
  89 #include <net/dn_fib.h>
  90
  91 struct dn_rt_hash_bucket
  92 {
  93         struct dn_route *chain;
  94         spinlock_t lock;
  95 } __attribute__((__aligned__(8)));
  96
  97 extern struct neigh_table dn_neigh_table;
  98
  99
 100 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 101
 102 static const int dn_rt_min_delay = 2 * HZ;
 103 static const int dn_rt_max_delay = 10 * HZ;
 104 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 105
 106 static unsigned long dn_rt_deadline;
 107
 108 static int dn_dst_gc(void);
 109 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 110 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 111 static void dn_dst_link_failure(struct sk_buff *);
 112 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
 113 static int dn_route_input(struct sk_buff *);
 114 static void dn_run_flush(unsigned long dummy);
 115
 116 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 117 static unsigned dn_rt_hash_mask;
 118
 119 static struct timer_list dn_route_timer;
 120 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 121 int decnet_dst_gc_interval = 2;
 122
 123 static struct dst_ops dn_dst_ops = {
 124         .family =               PF_DECnet,
 125         .protocol =             __constant_htons(ETH_P_DNA_RT),
 126         .gc_thresh =            128,
 127         .gc =                   dn_dst_gc,
 128         .check =                dn_dst_check,
 129         .negative_advice =      dn_dst_negative_advice,
 130         .link_failure =         dn_dst_link_failure,
 131         .update_pmtu =          dn_dst_update_pmtu,
 132         .entry_size =           sizeof(struct dn_route),
 133         .entries =              ATOMIC_INIT(0),
 134 };
 135
 136 static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
 137 {
 138         __u16 tmp = (__u16 __force)(src ^ dst);
 139         tmp ^= (tmp >> 3);
 140         tmp ^= (tmp >> 5);
 141         tmp ^= (tmp >> 10);
 142         return dn_rt_hash_mask & (unsigned)tmp;
 143 }
 144
 145 static inline void dnrt_free(struct dn_route *rt)
 146 {
 147         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 148 }
 149
 150 static inline void dnrt_drop(struct dn_route *rt)
 151 {
 152         dst_release(&rt->u.dst);
 153         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 154 }
 155
 156 static void dn_dst_check_expire(unsigned long dummy)
 157 {
 158         int i;
 159         struct dn_route *rt, **rtp;
 160         unsigned long now = jiffies;
 161         unsigned long expire = 120 * HZ;
 162
 163         for(i = 0; i <= dn_rt_hash_mask; i++) {
 164                 rtp = &dn_rt_hash_table[i].chain;
 165
 166                 spin_lock(&dn_rt_hash_table[i].lock);
 167                 while((rt=*rtp) != NULL) {
 168                         if (atomic_read(&rt->u.dst.__refcnt) ||
 169                                         (now - rt->u.dst.lastuse) < expire) {
 170                                 rtp = &rt->u.rt_next;
 171                                 continue;
 172                         }
 173                         *rtp = rt->u.rt_next;
 174                         rt->u.rt_next = NULL;
 175                         dnrt_free(rt);
 176                 }
 177                 spin_unlock(&dn_rt_hash_table[i].lock);
 178
 179                 if ((jiffies - now) > 0)
 180                         break;
 181         }
 182
 183         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 184 }
 185
 186 static int dn_dst_gc(void)
 187 {
 188         struct dn_route *rt, **rtp;
 189         int i;
 190         unsigned long now = jiffies;
 191         unsigned long expire = 10 * HZ;
 192
 193         for(i = 0; i <= dn_rt_hash_mask; i++) {
 194
 195                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 196                 rtp = &dn_rt_hash_table[i].chain;
 197
 198                 while((rt=*rtp) != NULL) {
 199                         if (atomic_read(&rt->u.dst.__refcnt) ||
 200                                         (now - rt->u.dst.lastuse) < expire) {
 201                                 rtp = &rt->u.rt_next;
 202                                 continue;
 203                         }
 204                         *rtp = rt->u.rt_next;
 205                         rt->u.rt_next = NULL;
 206                         dnrt_drop(rt);
 207                         break;
 208                 }
 209                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 210         }
 211
 212         return 0;
 213 }
 214
 215 /*
 216  * The decnet standards don't impose a particular minimum mtu, what they
 217  * do insist on is that the routing layer accepts a datagram of at least
 218  * 230 bytes long. Here we have to subtract the routing header length from
 219  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 220  * assume the worst and use a long header size.
 221  *
 222  * We update both the mtu and the advertised mss (i.e. the segment size we
 223  * advertise to the other end).
 224  */
 225 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
 226 {
 227         u32 min_mtu = 230;
 228         struct dn_dev *dn = dst->neighbour ?
 229                             (struct dn_dev *)dst->neighbour->dev->dn_ptr : NULL;
 230
 231         if (dn && dn->use_long == 0)
 232                 min_mtu -= 6;
 233         else
 234                 min_mtu -= 21;
 235
 236         if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= min_mtu) {
 237                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
 238                         dst->metrics[RTAX_MTU-1] = mtu;
 239                         dst_set_expires(dst, dn_rt_mtu_expires);
 240                 }
 241                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 242                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 243                         if (dst->metrics[RTAX_ADVMSS-1] > mss)
 244                                 dst->metrics[RTAX_ADVMSS-1] = mss;
 245                 }
 246         }
 247 }
 248
 249 /*
 250  * When a route has been marked obsolete. (e.g. routing cache flush)
 251  */
 252 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 253 {
 254         return NULL;
 255 }
 256
 257 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 258 {
 259         dst_release(dst);
 260         return NULL;
 261 }
 262
 263 static void dn_dst_link_failure(struct sk_buff *skb)
 264 {
 265         return;
 266 }
 267
 268 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
 269 {
 270         return memcmp(&fl1->nl_u.dn_u, &fl2->nl_u.dn_u, sizeof(fl1->nl_u.dn_u)) == 0 &&
 271                 fl1->oif == fl2->oif &&
 272                 fl1->iif == fl2->iif;
 273 }
 274
 275 static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
 276 {
 277         struct dn_route *rth, **rthp;
 278         unsigned long now = jiffies;
 279
 280         rthp = &dn_rt_hash_table[hash].chain;
 281
 282         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 283         while((rth = *rthp) != NULL) {
 284                 if (compare_keys(&rth->fl, &rt->fl)) {
 285                         /* Put it first */
 286                         *rthp = rth->u.rt_next;
 287                         rcu_assign_pointer(rth->u.rt_next,
 288                                            dn_rt_hash_table[hash].chain);
 289                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 290
 291                         rth->u.dst.__use++;
 292                         dst_hold(&rth->u.dst);
 293                         rth->u.dst.lastuse = now;
 294                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 295
 296                         dnrt_drop(rt);
 297                         *rp = rth;
 298                         return 0;
 299                 }
 300                 rthp = &rth->u.rt_next;
 301         }
 302
 303         rcu_assign_pointer(rt->u.rt_next, dn_rt_hash_table[hash].chain);
 304         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 305
 306         dst_hold(&rt->u.dst);
 307         rt->u.dst.__use++;
 308         rt->u.dst.lastuse = now;
 309         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 310         *rp = rt;
 311         return 0;
 312 }
 313
 314 void dn_run_flush(unsigned long dummy)
 315 {
 316         int i;
 317         struct dn_route *rt, *next;
 318
 319         for(i = 0; i < dn_rt_hash_mask; i++) {
 320                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 321
 322                 if ((rt = xchg(&dn_rt_hash_table[i].chain, NULL)) == NULL)
 323                         goto nothing_to_declare;
 324
 325                 for(; rt; rt=next) {
 326                         next = rt->u.rt_next;
 327                         rt->u.rt_next = NULL;
 328                         dst_free((struct dst_entry *)rt);
 329                 }
 330
 331 nothing_to_declare:
 332                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 333         }
 334 }
 335
 336 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 337
 338 void dn_rt_cache_flush(int delay)
 339 {
 340         unsigned long now = jiffies;
 341         int user_mode = !in_interrupt();
 342
 343         if (delay < 0)
 344                 delay = dn_rt_min_delay;
 345
 346         spin_lock_bh(&dn_rt_flush_lock);
 347
 348         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 349                 long tmo = (long)(dn_rt_deadline - now);
 350
 351                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 352                         tmo = 0;
 353
 354                 if (delay > tmo)
 355                         delay = tmo;
 356         }
 357
 358         if (delay <= 0) {
 359                 spin_unlock_bh(&dn_rt_flush_lock);
 360                 dn_run_flush(0);
 361                 return;
 362         }
 363
 364         if (dn_rt_deadline == 0)
 365                 dn_rt_deadline = now + dn_rt_max_delay;
 366
 367         dn_rt_flush_timer.expires = now + delay;
 368         add_timer(&dn_rt_flush_timer);
 369         spin_unlock_bh(&dn_rt_flush_lock);
 370 }
 371
 372 /**
 373  * dn_return_short - Return a short packet to its sender
 374  * @skb: The packet to return
 375  *
 376  */
 377 static int dn_return_short(struct sk_buff *skb)
 378 {
 379         struct dn_skb_cb *cb;
 380         unsigned char *ptr;
 381         __le16 *src;
 382         __le16 *dst;
 383         __le16 tmp;
 384
 385         /* Add back headers */
 386         skb_push(skb, skb->data - skb->nh.raw);
 387
 388         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 389                 return NET_RX_DROP;
 390
 391         cb = DN_SKB_CB(skb);
 392         /* Skip packet length and point to flags */
 393         ptr = skb->data + 2;
 394         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 395
 396         dst = (__le16 *)ptr;
 397         ptr += 2;
 398         src = (__le16 *)ptr;
 399         ptr += 2;
 400         *ptr = 0; /* Zero hop count */
 401
 402         /* Swap source and destination */
 403         tmp  = *src;
 404         *src = *dst;
 405         *dst = tmp;
 406
 407         skb->pkt_type = PACKET_OUTGOING;
 408         dn_rt_finish_output(skb, NULL, NULL);
 409         return NET_RX_SUCCESS;
 410 }
 411
 412 /**
 413  * dn_return_long - Return a long packet to its sender
 414  * @skb: The long format packet to return
 415  *
 416  */
 417 static int dn_return_long(struct sk_buff *skb)
 418 {
 419         struct dn_skb_cb *cb;
 420         unsigned char *ptr;
 421         unsigned char *src_addr, *dst_addr;
 422         unsigned char tmp[ETH_ALEN];
 423
 424         /* Add back all headers */
 425         skb_push(skb, skb->data - skb->nh.raw);
 426
 427         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 428                 return NET_RX_DROP;
 429
 430         cb = DN_SKB_CB(skb);
 431         /* Ignore packet length and point to flags */
 432         ptr = skb->data + 2;
 433
 434         /* Skip padding */
 435         if (*ptr & DN_RT_F_PF) {
 436                 char padlen = (*ptr & ~DN_RT_F_PF);
 437                 ptr += padlen;
 438         }
 439
 440         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 441         ptr += 2;
 442         dst_addr = ptr;
 443         ptr += 8;
 444         src_addr = ptr;
 445         ptr += 6;
 446         *ptr = 0; /* Zero hop count */
 447
 448         /* Swap source and destination */
 449         memcpy(tmp, src_addr, ETH_ALEN);
 450         memcpy(src_addr, dst_addr, ETH_ALEN);
 451         memcpy(dst_addr, tmp, ETH_ALEN);
 452
 453         skb->pkt_type = PACKET_OUTGOING;
 454         dn_rt_finish_output(skb, dst_addr, src_addr);
 455         return NET_RX_SUCCESS;
 456 }
 457
 458 /**
 459  * dn_route_rx_packet - Try and find a route for an incoming packet
 460  * @skb: The packet to find a route for
 461  *
 462  * Returns: result of input function if route is found, error code otherwise
 463  */
 464 static int dn_route_rx_packet(struct sk_buff *skb)
 465 {
 466         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 467         int err;
 468
 469         if ((err = dn_route_input(skb)) == 0)
 470                 return dst_input(skb);
 471
 472         if (decnet_debug_level & 4) {
 473                 char *devname = skb->dev ? skb->dev->name : "???";
 474                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 475                 printk(KERN_DEBUG
 476                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 477                         (int)cb->rt_flags, devname, skb->len,
 478                         dn_ntohs(cb->src), dn_ntohs(cb->dst),
 479                         err, skb->pkt_type);
 480         }
 481
 482         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 483                 switch(cb->rt_flags & DN_RT_PKT_MSK) {
 484                         case DN_RT_PKT_SHORT:
 485                                 return dn_return_short(skb);
 486                         case DN_RT_PKT_LONG:
 487                                 return dn_return_long(skb);
 488                 }
 489         }
 490
 491         kfree_skb(skb);
 492         return NET_RX_DROP;
 493 }
 494
 495 static int dn_route_rx_long(struct sk_buff *skb)
 496 {
 497         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 498         unsigned char *ptr = skb->data;
 499
 500         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 501                 goto drop_it;
 502
 503         skb_pull(skb, 20);
 504         skb->h.raw = skb->data;
 505
 506         /* Destination info */
 507         ptr += 2;
 508         cb->dst = dn_eth2dn(ptr);
 509         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 510                 goto drop_it;
 511         ptr += 6;
 512
 513
 514         /* Source info */
 515         ptr += 2;
 516         cb->src = dn_eth2dn(ptr);
 517         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 518                 goto drop_it;
 519         ptr += 6;
 520         /* Other junk */
 521         ptr++;
 522         cb->hops = *ptr++; /* Visit Count */
 523
 524         return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
 525
 526 drop_it:
 527         kfree_skb(skb);
 528         return NET_RX_DROP;
 529 }
 530
 531
 532
 533 static int dn_route_rx_short(struct sk_buff *skb)
 534 {
 535         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 536         unsigned char *ptr = skb->data;
 537
 538         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 539                 goto drop_it;
 540
 541         skb_pull(skb, 5);
 542         skb->h.raw = skb->data;
 543
 544         cb->dst = *(__le16 *)ptr;
 545         ptr += 2;
 546         cb->src = *(__le16 *)ptr;
 547         ptr += 2;
 548         cb->hops = *ptr & 0x3f;
 549
 550         return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
 551
 552 drop_it:
 553         kfree_skb(skb);
 554         return NET_RX_DROP;
 555 }
 556
 557 static int dn_route_discard(struct sk_buff *skb)
 558 {
 559         /*
 560          * I know we drop the packet here, but thats considered success in
 561          * this case
 562          */
 563         kfree_skb(skb);
 564         return NET_RX_SUCCESS;
 565 }
 566
 567 static int dn_route_ptp_hello(struct sk_buff *skb)
 568 {
 569         dn_dev_hello(skb);
 570         dn_neigh_pointopoint_hello(skb);
 571         return NET_RX_SUCCESS;
 572 }
 573
 574 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 575 {
 576         struct dn_skb_cb *cb;
 577         unsigned char flags = 0;
 578         __u16 len = dn_ntohs(*(__le16 *)skb->data);
 579         struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
 580         unsigned char padlen = 0;
 581
 582         if (dn == NULL)
 583                 goto dump_it;
 584
 585         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 586                 goto out;
 587
 588         if (!pskb_may_pull(skb, 3))
 589                 goto dump_it;
 590
 591         skb_pull(skb, 2);
 592
 593         if (len > skb->len)
 594                 goto dump_it;
 595
 596         skb_trim(skb, len);
 597
 598         flags = *skb->data;
 599
 600         cb = DN_SKB_CB(skb);
 601         cb->stamp = jiffies;
 602         cb->iif = dev->ifindex;
 603
 604         /*
 605          * If we have padding, remove it.
 606          */
 607         if (flags & DN_RT_F_PF) {
 608                 padlen = flags & ~DN_RT_F_PF;
 609                 if (!pskb_may_pull(skb, padlen + 1))
 610                         goto dump_it;
 611                 skb_pull(skb, padlen);
 612                 flags = *skb->data;
 613         }
 614
 615         skb->nh.raw = skb->data;
 616
 617         /*
 618          * Weed out future version DECnet
 619          */
 620         if (flags & DN_RT_F_VER)
 621                 goto dump_it;
 622
 623         cb->rt_flags = flags;
 624
 625         if (decnet_debug_level & 1)
 626                 printk(KERN_DEBUG
 627                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 628                         (int)flags, (dev) ? dev->name : "???", len, skb->len,
 629                         padlen);
 630
 631         if (flags & DN_RT_PKT_CNTL) {
 632                 if (unlikely(skb_linearize(skb)))
 633                         goto dump_it;
 634
 635                 switch(flags & DN_RT_CNTL_MSK) {
 636                         case DN_RT_PKT_INIT:
 637                                 dn_dev_init_pkt(skb);
 638                                 break;
 639                         case DN_RT_PKT_VERI:
 640                                 dn_dev_veri_pkt(skb);
 641                                 break;
 642                 }
 643
 644                 if (dn->parms.state != DN_DEV_S_RU)
 645                         goto dump_it;
 646
 647                 switch(flags & DN_RT_CNTL_MSK) {
 648                         case DN_RT_PKT_HELO:
 649                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_route_ptp_hello);
 650
 651                         case DN_RT_PKT_L1RT:
 652                         case DN_RT_PKT_L2RT:
 653                                 return NF_HOOK(PF_DECnet, NF_DN_ROUTE, skb, skb->dev, NULL, dn_route_discard);
 654                         case DN_RT_PKT_ERTH:
 655                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_router_hello);
 656
 657                         case DN_RT_PKT_EEDH:
 658                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_endnode_hello);
 659                 }
 660         } else {
 661                 if (dn->parms.state != DN_DEV_S_RU)
 662                         goto dump_it;
 663
 664                 skb_pull(skb, 1); /* Pull flags */
 665
 666                 switch(flags & DN_RT_PKT_MSK) {
 667                         case DN_RT_PKT_LONG:
 668                                 return dn_route_rx_long(skb);
 669                         case DN_RT_PKT_SHORT:
 670                                 return dn_route_rx_short(skb);
 671                 }
 672         }
 673
 674 dump_it:
 675         kfree_skb(skb);
 676 out:
 677         return NET_RX_DROP;
 678 }
 679
 680 static int dn_output(struct sk_buff *skb)
 681 {
 682         struct dst_entry *dst = skb->dst;
 683         struct dn_route *rt = (struct dn_route *)dst;
 684         struct net_device *dev = dst->dev;
 685         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 686         struct neighbour *neigh;
 687
 688         int err = -EINVAL;
 689
 690         if ((neigh = dst->neighbour) == NULL)
 691                 goto error;
 692
 693         skb->dev = dev;
 694
 695         cb->src = rt->rt_saddr;
 696         cb->dst = rt->rt_daddr;
 697
 698         /*
 699          * Always set the Intra-Ethernet bit on all outgoing packets
 700          * originated on this node. Only valid flag from upper layers
 701          * is return-to-sender-requested. Set hop count to 0 too.
 702          */
 703         cb->rt_flags &= ~DN_RT_F_RQR;
 704         cb->rt_flags |= DN_RT_F_IE;
 705         cb->hops = 0;
 706
 707         return NF_HOOK(PF_DECnet, NF_DN_LOCAL_OUT, skb, NULL, dev, neigh->output);
 708
 709 error:
 710         if (net_ratelimit())
 711                 printk(KERN_DEBUG "dn_output: This should not happen\n");
 712
 713         kfree_skb(skb);
 714
 715         return err;
 716 }
 717
 718 static int dn_forward(struct sk_buff *skb)
 719 {
 720         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 721         struct dst_entry *dst = skb->dst;
 722         struct dn_dev *dn_db = dst->dev->dn_ptr;
 723         struct dn_route *rt;
 724         struct neighbour *neigh = dst->neighbour;
 725         int header_len;
 726 #ifdef CONFIG_NETFILTER
 727         struct net_device *dev = skb->dev;
 728 #endif
 729
 730         if (skb->pkt_type != PACKET_HOST)
 731                 goto drop;
 732
 733         /* Ensure that we have enough space for headers */
 734         rt = (struct dn_route *)skb->dst;
 735         header_len = dn_db->use_long ? 21 : 6;
 736         if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+header_len))
 737                 goto drop;
 738
 739         /*
 740          * Hop count exceeded.
 741          */
 742         if (++cb->hops > 30)
 743                 goto drop;
 744
 745         skb->dev = rt->u.dst.dev;
 746
 747         /*
 748          * If packet goes out same interface it came in on, then set
 749          * the Intra-Ethernet bit. This has no effect for short
 750          * packets, so we don't need to test for them here.
 751          */
 752         cb->rt_flags &= ~DN_RT_F_IE;
 753         if (rt->rt_flags & RTCF_DOREDIRECT)
 754                 cb->rt_flags |= DN_RT_F_IE;
 755
 756         return NF_HOOK(PF_DECnet, NF_DN_FORWARD, skb, dev, skb->dev, neigh->output);
 757
 758 drop:
 759         kfree_skb(skb);
 760         return NET_RX_DROP;
 761 }
 762
 763 /*
 764  * Drop packet. This is used for endnodes and for
 765  * when we should not be forwarding packets from
 766  * this dest.
 767  */
 768 static int dn_blackhole(struct sk_buff *skb)
 769 {
 770         kfree_skb(skb);
 771         return NET_RX_DROP;
 772 }
 773
 774 /*
 775  * Used to catch bugs. This should never normally get
 776  * called.
 777  */
 778 static int dn_rt_bug(struct sk_buff *skb)
 779 {
 780         if (net_ratelimit()) {
 781                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 782
 783                 printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
 784                                 dn_ntohs(cb->src), dn_ntohs(cb->dst));
 785         }
 786
 787         kfree_skb(skb);
 788
 789         return NET_RX_BAD;
 790 }
 791
 792 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 793 {
 794         struct dn_fib_info *fi = res->fi;
 795         struct net_device *dev = rt->u.dst.dev;
 796         struct neighbour *n;
 797         unsigned mss;
 798
 799         if (fi) {
 800                 if (DN_FIB_RES_GW(*res) &&
 801                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 802                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 803                 memcpy(rt->u.dst.metrics, fi->fib_metrics,
 804                        sizeof(rt->u.dst.metrics));
 805         }
 806         rt->rt_type = res->type;
 807
 808         if (dev != NULL && rt->u.dst.neighbour == NULL) {
 809                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 810                 if (IS_ERR(n))
 811                         return PTR_ERR(n);
 812                 rt->u.dst.neighbour = n;
 813         }
 814
 815         if (rt->u.dst.metrics[RTAX_MTU-1] == 0 ||
 816             rt->u.dst.metrics[RTAX_MTU-1] > rt->u.dst.dev->mtu)
 817                 rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
 818         mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->u.dst));
 819         if (rt->u.dst.metrics[RTAX_ADVMSS-1] == 0 ||
 820             rt->u.dst.metrics[RTAX_ADVMSS-1] > mss)
 821                 rt->u.dst.metrics[RTAX_ADVMSS-1] = mss;
 822         return 0;
 823 }
 824
 825 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 826 {
 827         __u16 tmp = dn_ntohs(addr1) ^ dn_ntohs(addr2);
 828         int match = 16;
 829         while(tmp) {
 830                 tmp >>= 1;
 831                 match--;
 832         }
 833         return match;
 834 }
 835
 836 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 837 {
 838         __le16 saddr = 0;
 839         struct dn_dev *dn_db = dev->dn_ptr;
 840         struct dn_ifaddr *ifa;
 841         int best_match = 0;
 842         int ret;
 843
 844         read_lock(&dev_base_lock);
 845         for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
 846                 if (ifa->ifa_scope > scope)
 847                         continue;
 848                 if (!daddr) {
 849                         saddr = ifa->ifa_local;
 850                         break;
 851                 }
 852                 ret = dn_match_addr(daddr, ifa->ifa_local);
 853                 if (ret > best_match)
 854                         saddr = ifa->ifa_local;
 855                 if (best_match == 0)
 856                         saddr = ifa->ifa_local;
 857         }
 858         read_unlock(&dev_base_lock);
 859
 860         return saddr;
 861 }
 862
 863 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 864 {
 865         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 866 }
 867
 868 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 869 {
 870         __le16 mask = dnet_make_mask(res->prefixlen);
 871         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 872 }
 873
 874 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
 875 {
 876         struct flowi fl = { .nl_u = { .dn_u =
 877                                       { .daddr = oldflp->fld_dst,
 878                                         .saddr = oldflp->fld_src,
 879                                         .scope = RT_SCOPE_UNIVERSE,
 880 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 881                                         .fwmark = oldflp->fld_fwmark
 882 #endif
 883                                      } },
 884                             .iif = loopback_dev.ifindex,
 885                             .oif = oldflp->oif };
 886         struct dn_route *rt = NULL;
 887         struct net_device *dev_out = NULL;
 888         struct neighbour *neigh = NULL;
 889         unsigned hash;
 890         unsigned flags = 0;
 891         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 892         int err;
 893         int free_res = 0;
 894         __le16 gateway = 0;
 895
 896         if (decnet_debug_level & 16)
 897                 printk(KERN_DEBUG
 898                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 899                        " iif=%d oif=%d\n", dn_ntohs(oldflp->fld_dst),
 900                        dn_ntohs(oldflp->fld_src),
 901                        oldflp->fld_fwmark, loopback_dev.ifindex, oldflp->oif);
 902
 903         /* If we have an output interface, verify its a DECnet device */
 904         if (oldflp->oif) {
 905                 dev_out = dev_get_by_index(oldflp->oif);
 906                 err = -ENODEV;
 907                 if (dev_out && dev_out->dn_ptr == NULL) {
 908                         dev_put(dev_out);
 909                         dev_out = NULL;
 910                 }
 911                 if (dev_out == NULL)
 912                         goto out;
 913         }
 914
 915         /* If we have a source address, verify that its a local address */
 916         if (oldflp->fld_src) {
 917                 err = -EADDRNOTAVAIL;
 918
 919                 if (dev_out) {
 920                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
 921                                 goto source_ok;
 922                         dev_put(dev_out);
 923                         goto out;
 924                 }
 925                 read_lock(&dev_base_lock);
 926                 for(dev_out = dev_base; dev_out; dev_out = dev_out->next) {
 927                         if (!dev_out->dn_ptr)
 928                                 continue;
 929                         if (!dn_dev_islocal(dev_out, oldflp->fld_src))
 930                                 continue;
 931                         if ((dev_out->flags & IFF_LOOPBACK) &&
 932                             oldflp->fld_dst &&
 933                             !dn_dev_islocal(dev_out, oldflp->fld_dst))
 934                                 continue;
 935                         break;
 936                 }
 937                 read_unlock(&dev_base_lock);
 938                 if (dev_out == NULL)
 939                         goto out;
 940                 dev_hold(dev_out);
 941 source_ok:
 942                 ;
 943         }
 944
 945         /* No destination? Assume its local */
 946         if (!fl.fld_dst) {
 947                 fl.fld_dst = fl.fld_src;
 948
 949                 err = -EADDRNOTAVAIL;
 950                 if (dev_out)
 951                         dev_put(dev_out);
 952                 dev_out = &loopback_dev;
 953                 dev_hold(dev_out);
 954                 if (!fl.fld_dst) {
 955                         fl.fld_dst =
 956                         fl.fld_src = dnet_select_source(dev_out, 0,
 957                                                        RT_SCOPE_HOST);
 958                         if (!fl.fld_dst)
 959                                 goto out;
 960                 }
 961                 fl.oif = loopback_dev.ifindex;
 962                 res.type = RTN_LOCAL;
 963                 goto make_route;
 964         }
 965
 966         if (decnet_debug_level & 16)
 967                 printk(KERN_DEBUG
 968                        "dn_route_output_slow: initial checks complete."
 969                        " dst=%o4x src=%04x oif=%d try_hard=%d\n",
 970                        dn_ntohs(fl.fld_dst), dn_ntohs(fl.fld_src),
 971                        fl.oif, try_hard);
 972
 973         /*
 974          * N.B. If the kernel is compiled without router support then
 975          * dn_fib_lookup() will evaluate to non-zero so this if () block
 976          * will always be executed.
 977          */
 978         err = -ESRCH;
 979         if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
 980                 struct dn_dev *dn_db;
 981                 if (err != -ESRCH)
 982                         goto out;
 983                 /*
 984                  * Here the fallback is basically the standard algorithm for
 985                  * routing in endnodes which is described in the DECnet routing
 986                  * docs
 987                  *
 988                  * If we are not trying hard, look in neighbour cache.
 989                  * The result is tested to ensure that if a specific output
 990                  * device/source address was requested, then we honour that
 991                  * here
 992                  */
 993                 if (!try_hard) {
 994                         neigh = neigh_lookup_nodev(&dn_neigh_table, &fl.fld_dst);
 995                         if (neigh) {
 996                                 if ((oldflp->oif &&
 997                                     (neigh->dev->ifindex != oldflp->oif)) ||
 998                                     (oldflp->fld_src &&
 999                                     (!dn_dev_islocal(neigh->dev,
1000                                                       oldflp->fld_src)))) {
1001                                         neigh_release(neigh);
1002                                         neigh = NULL;
1003                                 } else {
1004                                         if (dev_out)
1005                                                 dev_put(dev_out);
1006                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
1007                                                 dev_out = &loopback_dev;
1008                                                 res.type = RTN_LOCAL;
1009                                         } else {
1010                                                 dev_out = neigh->dev;
1011                                         }
1012                                         dev_hold(dev_out);
1013                                         goto select_source;
1014                                 }
1015                         }
1016                 }
1017
1018                 /* Not there? Perhaps its a local address */
1019                 if (dev_out == NULL)
1020                         dev_out = dn_dev_get_default();
1021                 err = -ENODEV;
1022                 if (dev_out == NULL)
1023                         goto out;
1024                 dn_db = dev_out->dn_ptr;
1025                 /* Possible improvement - check all devices for local addr */
1026                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1027                         dev_put(dev_out);
1028                         dev_out = &loopback_dev;
1029                         dev_hold(dev_out);
1030                         res.type = RTN_LOCAL;
1031                         goto select_source;
1032                 }
1033                 /* Not local either.... try sending it to the default router */
1034                 neigh = neigh_clone(dn_db->router);
1035                 BUG_ON(neigh && neigh->dev != dev_out);
1036
1037                 /* Ok then, we assume its directly connected and move on */
1038 select_source:
1039                 if (neigh)
1040                         gateway = ((struct dn_neigh *)neigh)->addr;
1041                 if (gateway == 0)
1042                         gateway = fl.fld_dst;
1043                 if (fl.fld_src == 0) {
1044                         fl.fld_src = dnet_select_source(dev_out, gateway,
1045                                                          res.type == RTN_LOCAL ?
1046                                                          RT_SCOPE_HOST :
1047                                                          RT_SCOPE_LINK);
1048                         if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1049                                 goto e_addr;
1050                 }
1051                 fl.oif = dev_out->ifindex;
1052                 goto make_route;
1053         }
1054         free_res = 1;
1055
1056         if (res.type == RTN_NAT)
1057                 goto e_inval;
1058
1059         if (res.type == RTN_LOCAL) {
1060                 if (!fl.fld_src)
1061                         fl.fld_src = fl.fld_dst;
1062                 if (dev_out)
1063                         dev_put(dev_out);
1064                 dev_out = &loopback_dev;
1065                 dev_hold(dev_out);
1066                 fl.oif = dev_out->ifindex;
1067                 if (res.fi)
1068                         dn_fib_info_put(res.fi);
1069                 res.fi = NULL;
1070                 goto make_route;
1071         }
1072
1073         if (res.fi->fib_nhs > 1 && fl.oif == 0)
1074                 dn_fib_select_multipath(&fl, &res);
1075
1076         /*
1077          * We could add some logic to deal with default routes here and
1078          * get rid of some of the special casing above.
1079          */
1080
1081         if (!fl.fld_src)
1082                 fl.fld_src = DN_FIB_RES_PREFSRC(res);
1083
1084         if (dev_out)
1085                 dev_put(dev_out);
1086         dev_out = DN_FIB_RES_DEV(res);
1087         dev_hold(dev_out);
1088         fl.oif = dev_out->ifindex;
1089         gateway = DN_FIB_RES_GW(res);
1090
1091 make_route:
1092         if (dev_out->flags & IFF_LOOPBACK)
1093                 flags |= RTCF_LOCAL;
1094
1095         rt = dst_alloc(&dn_dst_ops);
1096         if (rt == NULL)
1097                 goto e_nobufs;
1098
1099         atomic_set(&rt->u.dst.__refcnt, 1);
1100         rt->u.dst.flags   = DST_HOST;
1101
1102         rt->fl.fld_src    = oldflp->fld_src;
1103         rt->fl.fld_dst    = oldflp->fld_dst;
1104         rt->fl.oif        = oldflp->oif;
1105         rt->fl.iif        = 0;
1106 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1107         rt->fl.fld_fwmark = oldflp->fld_fwmark;
1108 #endif
1109
1110         rt->rt_saddr      = fl.fld_src;
1111         rt->rt_daddr      = fl.fld_dst;
1112         rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1113         rt->rt_local_src  = fl.fld_src;
1114
1115         rt->rt_dst_map    = fl.fld_dst;
1116         rt->rt_src_map    = fl.fld_src;
1117
1118         rt->u.dst.dev = dev_out;
1119         dev_hold(dev_out);
1120         rt->u.dst.neighbour = neigh;
1121         neigh = NULL;
1122
1123         rt->u.dst.lastuse = jiffies;
1124         rt->u.dst.output  = dn_output;
1125         rt->u.dst.input   = dn_rt_bug;
1126         rt->rt_flags      = flags;
1127         if (flags & RTCF_LOCAL)
1128                 rt->u.dst.input = dn_nsp_rx;
1129
1130         err = dn_rt_set_next_hop(rt, &res);
1131         if (err)
1132                 goto e_neighbour;
1133
1134         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1135         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1136
1137 done:
1138         if (neigh)
1139                 neigh_release(neigh);
1140         if (free_res)
1141                 dn_fib_res_put(&res);
1142         if (dev_out)
1143                 dev_put(dev_out);
1144 out:
1145         return err;
1146
1147 e_addr:
1148         err = -EADDRNOTAVAIL;
1149         goto done;
1150 e_inval:
1151         err = -EINVAL;
1152         goto done;
1153 e_nobufs:
1154         err = -ENOBUFS;
1155         goto done;
1156 e_neighbour:
1157         dst_free(&rt->u.dst);
1158         goto e_nobufs;
1159 }
1160
1161
1162 /*
1163  * N.B. The flags may be moved into the flowi at some future stage.
1164  */
1165 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1166 {
1167         unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1168         struct dn_route *rt = NULL;
1169
1170         if (!(flags & MSG_TRYHARD)) {
1171                 rcu_read_lock_bh();
1172                 for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt;
1173                         rt = rcu_dereference(rt->u.rt_next)) {
1174                         if ((flp->fld_dst == rt->fl.fld_dst) &&
1175                             (flp->fld_src == rt->fl.fld_src) &&
1176 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1177                             (flp->fld_fwmark == rt->fl.fld_fwmark) &&
1178 #endif
1179                             (rt->fl.iif == 0) &&
1180                             (rt->fl.oif == flp->oif)) {
1181                                 rt->u.dst.lastuse = jiffies;
1182                                 dst_hold(&rt->u.dst);
1183                                 rt->u.dst.__use++;
1184                                 rcu_read_unlock_bh();
1185                                 *pprt = &rt->u.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(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(pprt, fl, sk, !(flags & MSG_DONTWAIT));
1213         }
1214         return err;
1215 }
1216
1217 static int dn_route_input_slow(struct sk_buff *skb)
1218 {
1219         struct dn_route *rt = NULL;
1220         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1221         struct net_device *in_dev = skb->dev;
1222         struct net_device *out_dev = NULL;
1223         struct dn_dev *dn_db;
1224         struct neighbour *neigh = NULL;
1225         unsigned hash;
1226         int flags = 0;
1227         __le16 gateway = 0;
1228         __le16 local_src = 0;
1229         struct flowi fl = { .nl_u = { .dn_u =
1230                                      { .daddr = cb->dst,
1231                                        .saddr = cb->src,
1232                                        .scope = RT_SCOPE_UNIVERSE,
1233 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1234                                        .fwmark = skb->nfmark
1235 #endif
1236                                     } },
1237                             .iif = skb->dev->ifindex };
1238         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1239         int err = -EINVAL;
1240         int free_res = 0;
1241
1242         dev_hold(in_dev);
1243
1244         if ((dn_db = in_dev->dn_ptr) == NULL)
1245                 goto out;
1246
1247         /* Zero source addresses are not allowed */
1248         if (fl.fld_src == 0)
1249                 goto out;
1250
1251         /*
1252          * In this case we've just received a packet from a source
1253          * outside ourselves pretending to come from us. We don't
1254          * allow it any further to prevent routing loops, spoofing and
1255          * other nasties. Loopback packets already have the dst attached
1256          * so this only affects packets which have originated elsewhere.
1257          */
1258         err  = -ENOTUNIQ;
1259         if (dn_dev_islocal(in_dev, cb->src))
1260                 goto out;
1261
1262         err = dn_fib_lookup(&fl, &res);
1263         if (err) {
1264                 if (err != -ESRCH)
1265                         goto out;
1266                 /*
1267                  * Is the destination us ?
1268                  */
1269                 if (!dn_dev_islocal(in_dev, cb->dst))
1270                         goto e_inval;
1271
1272                 res.type = RTN_LOCAL;
1273                 flags |= RTCF_DIRECTSRC;
1274         } else {
1275                 __le16 src_map = fl.fld_src;
1276                 free_res = 1;
1277
1278                 out_dev = DN_FIB_RES_DEV(res);
1279                 if (out_dev == NULL) {
1280                         if (net_ratelimit())
1281                                 printk(KERN_CRIT "Bug in dn_route_input_slow() "
1282                                                  "No output device\n");
1283                         goto e_inval;
1284                 }
1285                 dev_hold(out_dev);
1286
1287                 if (res.r)
1288                         src_map = fl.fld_src; /* no NAT support for now */
1289
1290                 gateway = DN_FIB_RES_GW(res);
1291                 if (res.type == RTN_NAT) {
1292                         fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1293                         dn_fib_res_put(&res);
1294                         free_res = 0;
1295                         if (dn_fib_lookup(&fl, &res))
1296                                 goto e_inval;
1297                         free_res = 1;
1298                         if (res.type != RTN_UNICAST)
1299                                 goto e_inval;
1300                         flags |= RTCF_DNAT;
1301                         gateway = fl.fld_dst;
1302                 }
1303                 fl.fld_src = src_map;
1304         }
1305
1306         switch(res.type) {
1307         case RTN_UNICAST:
1308                 /*
1309                  * Forwarding check here, we only check for forwarding
1310                  * being turned off, if you want to only forward intra
1311                  * area, its up to you to set the routing tables up
1312                  * correctly.
1313                  */
1314                 if (dn_db->parms.forwarding == 0)
1315                         goto e_inval;
1316
1317                 if (res.fi->fib_nhs > 1 && fl.oif == 0)
1318                         dn_fib_select_multipath(&fl, &res);
1319
1320                 /*
1321                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1322                  * flag as a hint to set the intra-ethernet bit when
1323                  * forwarding. If we've got NAT in operation, we don't do
1324                  * this optimisation.
1325                  */
1326                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1327                         flags |= RTCF_DOREDIRECT;
1328
1329                 local_src = DN_FIB_RES_PREFSRC(res);
1330
1331         case RTN_BLACKHOLE:
1332         case RTN_UNREACHABLE:
1333                 break;
1334         case RTN_LOCAL:
1335                 flags |= RTCF_LOCAL;
1336                 fl.fld_src = cb->dst;
1337                 fl.fld_dst = cb->src;
1338
1339                 /* Routing tables gave us a gateway */
1340                 if (gateway)
1341                         goto make_route;
1342
1343                 /* Packet was intra-ethernet, so we know its on-link */
1344                 if (cb->rt_flags | DN_RT_F_IE) {
1345                         gateway = cb->src;
1346                         flags |= RTCF_DIRECTSRC;
1347                         goto make_route;
1348                 }
1349
1350                 /* Use the default router if there is one */
1351                 neigh = neigh_clone(dn_db->router);
1352                 if (neigh) {
1353                         gateway = ((struct dn_neigh *)neigh)->addr;
1354                         goto make_route;
1355                 }
1356
1357                 /* Close eyes and pray */
1358                 gateway = cb->src;
1359                 flags |= RTCF_DIRECTSRC;
1360                 goto make_route;
1361         default:
1362                 goto e_inval;
1363         }
1364
1365 make_route:
1366         rt = dst_alloc(&dn_dst_ops);
1367         if (rt == NULL)
1368                 goto e_nobufs;
1369
1370         rt->rt_saddr      = fl.fld_src;
1371         rt->rt_daddr      = fl.fld_dst;
1372         rt->rt_gateway    = fl.fld_dst;
1373         if (gateway)
1374                 rt->rt_gateway = gateway;
1375         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1376
1377         rt->rt_dst_map    = fl.fld_dst;
1378         rt->rt_src_map    = fl.fld_src;
1379
1380         rt->fl.fld_src    = cb->src;
1381         rt->fl.fld_dst    = cb->dst;
1382         rt->fl.oif        = 0;
1383         rt->fl.iif        = in_dev->ifindex;
1384         rt->fl.fld_fwmark = fl.fld_fwmark;
1385
1386         rt->u.dst.flags = DST_HOST;
1387         rt->u.dst.neighbour = neigh;
1388         rt->u.dst.dev = out_dev;
1389         rt->u.dst.lastuse = jiffies;
1390         rt->u.dst.output = dn_rt_bug;
1391         switch(res.type) {
1392                 case RTN_UNICAST:
1393                         rt->u.dst.input = dn_forward;
1394                         break;
1395                 case RTN_LOCAL:
1396                         rt->u.dst.output = dn_output;
1397                         rt->u.dst.input = dn_nsp_rx;
1398                         rt->u.dst.dev = in_dev;
1399                         flags |= RTCF_LOCAL;
1400                         break;
1401                 default:
1402                 case RTN_UNREACHABLE:
1403                 case RTN_BLACKHOLE:
1404                         rt->u.dst.input = dn_blackhole;
1405         }
1406         rt->rt_flags = flags;
1407         if (rt->u.dst.dev)
1408                 dev_hold(rt->u.dst.dev);
1409
1410         err = dn_rt_set_next_hop(rt, &res);
1411         if (err)
1412                 goto e_neighbour;
1413
1414         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1415         dn_insert_route(rt, hash, (struct dn_route **)&skb->dst);
1416
1417 done:
1418         if (neigh)
1419                 neigh_release(neigh);
1420         if (free_res)
1421                 dn_fib_res_put(&res);
1422         dev_put(in_dev);
1423         if (out_dev)
1424                 dev_put(out_dev);
1425 out:
1426         return err;
1427
1428 e_inval:
1429         err = -EINVAL;
1430         goto done;
1431
1432 e_nobufs:
1433         err = -ENOBUFS;
1434         goto done;
1435
1436 e_neighbour:
1437         dst_free(&rt->u.dst);
1438         goto done;
1439 }
1440
1441 int dn_route_input(struct sk_buff *skb)
1442 {
1443         struct dn_route *rt;
1444         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1445         unsigned hash = dn_hash(cb->src, cb->dst);
1446
1447         if (skb->dst)
1448                 return 0;
1449
1450         rcu_read_lock();
1451         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1452             rt = rcu_dereference(rt->u.rt_next)) {
1453                 if ((rt->fl.fld_src == cb->src) &&
1454                     (rt->fl.fld_dst == cb->dst) &&
1455                     (rt->fl.oif == 0) &&
1456 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1457                     (rt->fl.fld_fwmark == skb->nfmark) &&
1458 #endif
1459                     (rt->fl.iif == cb->iif)) {
1460                         rt->u.dst.lastuse = jiffies;
1461                         dst_hold(&rt->u.dst);
1462                         rt->u.dst.__use++;
1463                         rcu_read_unlock();
1464                         skb->dst = (struct dst_entry *)rt;
1465                         return 0;
1466                 }
1467         }
1468         rcu_read_unlock();
1469
1470         return dn_route_input_slow(skb);
1471 }
1472
1473 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1474                            int event, int nowait, unsigned int flags)
1475 {
1476         struct dn_route *rt = (struct dn_route *)skb->dst;
1477         struct rtmsg *r;
1478         struct nlmsghdr *nlh;
1479         unsigned char *b = skb->tail;
1480         struct rta_cacheinfo ci;
1481
1482         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1483         r = NLMSG_DATA(nlh);
1484         r->rtm_family = AF_DECnet;
1485         r->rtm_dst_len = 16;
1486         r->rtm_src_len = 0;
1487         r->rtm_tos = 0;
1488         r->rtm_table = RT_TABLE_MAIN;
1489         RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
1490         r->rtm_type = rt->rt_type;
1491         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1492         r->rtm_scope = RT_SCOPE_UNIVERSE;
1493         r->rtm_protocol = RTPROT_UNSPEC;
1494         if (rt->rt_flags & RTCF_NOTIFY)
1495                 r->rtm_flags |= RTM_F_NOTIFY;
1496         RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1497         if (rt->fl.fld_src) {
1498                 r->rtm_src_len = 16;
1499                 RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1500         }
1501         if (rt->u.dst.dev)
1502                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
1503         /*
1504          * Note to self - change this if input routes reverse direction when
1505          * they deal only with inputs and not with replies like they do
1506          * currently.
1507          */
1508         RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1509         if (rt->rt_daddr != rt->rt_gateway)
1510                 RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1511         if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
1512                 goto rtattr_failure;
1513         ci.rta_lastuse = jiffies_to_clock_t(jiffies - rt->u.dst.lastuse);
1514         ci.rta_used     = rt->u.dst.__use;
1515         ci.rta_clntref  = atomic_read(&rt->u.dst.__refcnt);
1516         if (rt->u.dst.expires)
1517                 ci.rta_expires = jiffies_to_clock_t(rt->u.dst.expires - jiffies);
1518         else
1519                 ci.rta_expires = 0;
1520         ci.rta_error    = rt->u.dst.error;
1521         ci.rta_id       = ci.rta_ts = ci.rta_tsage = 0;
1522         RTA_PUT(skb, RTA_CACHEINFO, sizeof(ci), &ci);
1523         if (rt->fl.iif)
1524                 RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1525
1526         nlh->nlmsg_len = skb->tail - b;
1527         return skb->len;
1528
1529 nlmsg_failure:
1530 rtattr_failure:
1531         skb_trim(skb, b - skb->data);
1532         return -1;
1533 }
1534
1535 /*
1536  * This is called by both endnodes and routers now.
1537  */
1538 int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1539 {
1540         struct rtattr **rta = arg;
1541         struct rtmsg *rtm = NLMSG_DATA(nlh);
1542         struct dn_route *rt = NULL;
1543         struct dn_skb_cb *cb;
1544         int err;
1545         struct sk_buff *skb;
1546         struct flowi fl;
1547
1548         memset(&fl, 0, sizeof(fl));
1549         fl.proto = DNPROTO_NSP;
1550
1551         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1552         if (skb == NULL)
1553                 return -ENOBUFS;
1554         skb->mac.raw = skb->data;
1555         cb = DN_SKB_CB(skb);
1556
1557         if (rta[RTA_SRC-1])
1558                 memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1559         if (rta[RTA_DST-1])
1560                 memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1561         if (rta[RTA_IIF-1])
1562                 memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1563
1564         if (fl.iif) {
1565                 struct net_device *dev;
1566                 if ((dev = dev_get_by_index(fl.iif)) == NULL) {
1567                         kfree_skb(skb);
1568                         return -ENODEV;
1569                 }
1570                 if (!dev->dn_ptr) {
1571                         dev_put(dev);
1572                         kfree_skb(skb);
1573                         return -ENODEV;
1574                 }
1575                 skb->protocol = __constant_htons(ETH_P_DNA_RT);
1576                 skb->dev = dev;
1577                 cb->src = fl.fld_src;
1578                 cb->dst = fl.fld_dst;
1579                 local_bh_disable();
1580                 err = dn_route_input(skb);
1581                 local_bh_enable();
1582                 memset(cb, 0, sizeof(struct dn_skb_cb));
1583                 rt = (struct dn_route *)skb->dst;
1584                 if (!err && -rt->u.dst.error)
1585                         err = rt->u.dst.error;
1586         } else {
1587                 int oif = 0;
1588                 if (rta[RTA_OIF - 1])
1589                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1590                 fl.oif = oif;
1591                 err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1592         }
1593
1594         if (skb->dev)
1595                 dev_put(skb->dev);
1596         skb->dev = NULL;
1597         if (err)
1598                 goto out_free;
1599         skb->dst = &rt->u.dst;
1600         if (rtm->rtm_flags & RTM_F_NOTIFY)
1601                 rt->rt_flags |= RTCF_NOTIFY;
1602
1603         NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
1604
1605         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1606
1607         if (err == 0)
1608                 goto out_free;
1609         if (err < 0) {
1610                 err = -EMSGSIZE;
1611                 goto out_free;
1612         }
1613
1614         return rtnl_unicast(skb, NETLINK_CB(in_skb).pid);
1615
1616 out_free:
1617         kfree_skb(skb);
1618         return err;
1619 }
1620
1621 /*
1622  * For routers, this is called from dn_fib_dump, but for endnodes its
1623  * called directly from the rtnetlink dispatch table.
1624  */
1625 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1626 {
1627         struct dn_route *rt;
1628         int h, s_h;
1629         int idx, s_idx;
1630
1631         if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1632                 return -EINVAL;
1633         if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1634                 return 0;
1635
1636         s_h = cb->args[0];
1637         s_idx = idx = cb->args[1];
1638         for(h = 0; h <= dn_rt_hash_mask; h++) {
1639                 if (h < s_h)
1640                         continue;
1641                 if (h > s_h)
1642                         s_idx = 0;
1643                 rcu_read_lock_bh();
1644                 for(rt = rcu_dereference(dn_rt_hash_table[h].chain), idx = 0;
1645                         rt;
1646                         rt = rcu_dereference(rt->u.rt_next), idx++) {
1647                         if (idx < s_idx)
1648                                 continue;
1649                         skb->dst = dst_clone(&rt->u.dst);
1650                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1651                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1652                                         1, NLM_F_MULTI) <= 0) {
1653                                 dst_release(xchg(&skb->dst, NULL));
1654                                 rcu_read_unlock_bh();
1655                                 goto done;
1656                         }
1657                         dst_release(xchg(&skb->dst, NULL));
1658                 }
1659                 rcu_read_unlock_bh();
1660         }
1661
1662 done:
1663         cb->args[0] = h;
1664         cb->args[1] = idx;
1665         return skb->len;
1666 }
1667
1668 #ifdef CONFIG_PROC_FS
1669 struct dn_rt_cache_iter_state {
1670         int bucket;
1671 };
1672
1673 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1674 {
1675         struct dn_route *rt = NULL;
1676         struct dn_rt_cache_iter_state *s = seq->private;
1677
1678         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1679                 rcu_read_lock_bh();
1680                 rt = dn_rt_hash_table[s->bucket].chain;
1681                 if (rt)
1682                         break;
1683                 rcu_read_unlock_bh();
1684         }
1685         return rt;
1686 }
1687
1688 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1689 {
1690         struct dn_rt_cache_iter_state *s = rcu_dereference(seq->private);
1691
1692         rt = rt->u.rt_next;
1693         while(!rt) {
1694                 rcu_read_unlock_bh();
1695                 if (--s->bucket < 0)
1696                         break;
1697                 rcu_read_lock_bh();
1698                 rt = dn_rt_hash_table[s->bucket].chain;
1699         }
1700         return rt;
1701 }
1702
1703 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1704 {
1705         struct dn_route *rt = dn_rt_cache_get_first(seq);
1706
1707         if (rt) {
1708                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1709                         --*pos;
1710         }
1711         return *pos ? NULL : rt;
1712 }
1713
1714 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1715 {
1716         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1717         ++*pos;
1718         return rt;
1719 }
1720
1721 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1722 {
1723         if (v)
1724                 rcu_read_unlock_bh();
1725 }
1726
1727 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1728 {
1729         struct dn_route *rt = v;
1730         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1731
1732         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1733                         rt->u.dst.dev ? rt->u.dst.dev->name : "*",
1734                         dn_addr2asc(dn_ntohs(rt->rt_daddr), buf1),
1735                         dn_addr2asc(dn_ntohs(rt->rt_saddr), buf2),
1736                         atomic_read(&rt->u.dst.__refcnt),
1737                         rt->u.dst.__use,
1738                         (int) dst_metric(&rt->u.dst, RTAX_RTT));
1739         return 0;
1740 }
1741
1742 static struct seq_operations dn_rt_cache_seq_ops = {
1743         .start  = dn_rt_cache_seq_start,
1744         .next   = dn_rt_cache_seq_next,
1745         .stop   = dn_rt_cache_seq_stop,
1746         .show   = dn_rt_cache_seq_show,
1747 };
1748
1749 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1750 {
1751         struct seq_file *seq;
1752         int rc = -ENOMEM;
1753         struct dn_rt_cache_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
1754
1755         if (!s)
1756                 goto out;
1757         rc = seq_open(file, &dn_rt_cache_seq_ops);
1758         if (rc)
1759                 goto out_kfree;
1760         seq             = file->private_data;
1761         seq->private    = s;
1762         memset(s, 0, sizeof(*s));
1763 out:
1764         return rc;
1765 out_kfree:
1766         kfree(s);
1767         goto out;
1768 }
1769
1770 static struct file_operations dn_rt_cache_seq_fops = {
1771         .owner   = THIS_MODULE,
1772         .open    = dn_rt_cache_seq_open,
1773         .read    = seq_read,
1774         .llseek  = seq_lseek,
1775         .release = seq_release_private,
1776 };
1777
1778 #endif /* CONFIG_PROC_FS */
1779
1780 void __init dn_route_init(void)
1781 {
1782         int i, goal, order;
1783
1784         dn_dst_ops.kmem_cachep =
1785                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1786                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1787         init_timer(&dn_route_timer);
1788         dn_route_timer.function = dn_dst_check_expire;
1789         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1790         add_timer(&dn_route_timer);
1791
1792         goal = num_physpages >> (26 - PAGE_SHIFT);
1793
1794         for(order = 0; (1UL << order) < goal; order++)
1795                 /* NOTHING */;
1796
1797         /*
1798          * Only want 1024 entries max, since the table is very, very unlikely
1799          * to be larger than that.
1800          */
1801         while(order && ((((1UL << order) * PAGE_SIZE) /
1802                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1803                 order--;
1804
1805         do {
1806                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1807                         sizeof(struct dn_rt_hash_bucket);
1808                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1809                         dn_rt_hash_mask--;
1810                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1811                         __get_free_pages(GFP_ATOMIC, order);
1812         } while (dn_rt_hash_table == NULL && --order > 0);
1813
1814         if (!dn_rt_hash_table)
1815                 panic("Failed to allocate DECnet route cache hash table\n");
1816
1817         printk(KERN_INFO
1818                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1819                 dn_rt_hash_mask,
1820                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1821
1822         dn_rt_hash_mask--;
1823         for(i = 0; i <= dn_rt_hash_mask; i++) {
1824                 spin_lock_init(&dn_rt_hash_table[i].lock);
1825                 dn_rt_hash_table[i].chain = NULL;
1826         }
1827
1828         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1829
1830         proc_net_fops_create("decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1831 }
1832
1833 void __exit dn_route_cleanup(void)
1834 {
1835         del_timer(&dn_route_timer);
1836         dn_run_flush(0);
1837
1838         proc_net_remove("decnet_cache");
1839 }
1840