git.oblomov.eu Git - linux-2.6/blob - 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/net_namespace.h>
  81 #include <net/netlink.h>
  82 #include <net/neighbour.h>
  83 #include <net/dst.h>
  84 #include <net/flow.h>
  85 #include <net/fib_rules.h>
  86 #include <net/dn.h>
  87 #include <net/dn_dev.h>
  88 #include <net/dn_nsp.h>
  89 #include <net/dn_route.h>
  90 #include <net/dn_neigh.h>
  91 #include <net/dn_fib.h>
  92
  93 struct dn_rt_hash_bucket
  94 {
  95         struct dn_route *chain;
  96         spinlock_t lock;
  97 };
  98
  99 extern struct neigh_table dn_neigh_table;
 100
 101
 102 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 103
 104 static const int dn_rt_min_delay = 2 * HZ;
 105 static const int dn_rt_max_delay = 10 * HZ;
 106 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 107
 108 static unsigned long dn_rt_deadline;
 109
 110 static int dn_dst_gc(struct dst_ops *ops);
 111 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 112 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 113 static void dn_dst_link_failure(struct sk_buff *);
 114 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
 115 static int dn_route_input(struct sk_buff *);
 116 static void dn_run_flush(unsigned long dummy);
 117
 118 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 119 static unsigned dn_rt_hash_mask;
 120
 121 static struct timer_list dn_route_timer;
 122 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 123 int decnet_dst_gc_interval = 2;
 124
 125 static struct dst_ops dn_dst_ops = {
 126         .family =               PF_DECnet,
 127         .protocol =             cpu_to_be16(ETH_P_DNA_RT),
 128         .gc_thresh =            128,
 129         .gc =                   dn_dst_gc,
 130         .check =                dn_dst_check,
 131         .negative_advice =      dn_dst_negative_advice,
 132         .link_failure =         dn_dst_link_failure,
 133         .update_pmtu =          dn_dst_update_pmtu,
 134         .entries =              ATOMIC_INIT(0),
 135 };
 136
 137 static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
 138 {
 139         __u16 tmp = (__u16 __force)(src ^ dst);
 140         tmp ^= (tmp >> 3);
 141         tmp ^= (tmp >> 5);
 142         tmp ^= (tmp >> 10);
 143         return dn_rt_hash_mask & (unsigned)tmp;
 144 }
 145
 146 static inline void dnrt_free(struct dn_route *rt)
 147 {
 148         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 149 }
 150
 151 static inline void dnrt_drop(struct dn_route *rt)
 152 {
 153         dst_release(&rt->u.dst);
 154         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 155 }
 156
 157 static void dn_dst_check_expire(unsigned long dummy)
 158 {
 159         int i;
 160         struct dn_route *rt, **rtp;
 161         unsigned long now = jiffies;
 162         unsigned long expire = 120 * HZ;
 163
 164         for(i = 0; i <= dn_rt_hash_mask; i++) {
 165                 rtp = &dn_rt_hash_table[i].chain;
 166
 167                 spin_lock(&dn_rt_hash_table[i].lock);
 168                 while((rt=*rtp) != NULL) {
 169                         if (atomic_read(&rt->u.dst.__refcnt) ||
 170                                         (now - rt->u.dst.lastuse) < expire) {
 171                                 rtp = &rt->u.dst.dn_next;
 172                                 continue;
 173                         }
 174                         *rtp = rt->u.dst.dn_next;
 175                         rt->u.dst.dn_next = NULL;
 176                         dnrt_free(rt);
 177                 }
 178                 spin_unlock(&dn_rt_hash_table[i].lock);
 179
 180                 if ((jiffies - now) > 0)
 181                         break;
 182         }
 183
 184         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 185 }
 186
 187 static int dn_dst_gc(struct dst_ops *ops)
 188 {
 189         struct dn_route *rt, **rtp;
 190         int i;
 191         unsigned long now = jiffies;
 192         unsigned long expire = 10 * HZ;
 193
 194         for(i = 0; i <= dn_rt_hash_mask; i++) {
 195
 196                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 197                 rtp = &dn_rt_hash_table[i].chain;
 198
 199                 while((rt=*rtp) != NULL) {
 200                         if (atomic_read(&rt->u.dst.__refcnt) ||
 201                                         (now - rt->u.dst.lastuse) < expire) {
 202                                 rtp = &rt->u.dst.dn_next;
 203                                 continue;
 204                         }
 205                         *rtp = rt->u.dst.dn_next;
 206                         rt->u.dst.dn_next = NULL;
 207                         dnrt_drop(rt);
 208                         break;
 209                 }
 210                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 211         }
 212
 213         return 0;
 214 }
 215
 216 /*
 217  * The decnet standards don't impose a particular minimum mtu, what they
 218  * do insist on is that the routing layer accepts a datagram of at least
 219  * 230 bytes long. Here we have to subtract the routing header length from
 220  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 221  * assume the worst and use a long header size.
 222  *
 223  * We update both the mtu and the advertised mss (i.e. the segment size we
 224  * advertise to the other end).
 225  */
 226 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
 227 {
 228         u32 min_mtu = 230;
 229         struct dn_dev *dn = dst->neighbour ?
 230                             (struct dn_dev *)dst->neighbour->dev->dn_ptr : NULL;
 231
 232         if (dn && dn->use_long == 0)
 233                 min_mtu -= 6;
 234         else
 235                 min_mtu -= 21;
 236
 237         if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
 238                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
 239                         dst->metrics[RTAX_MTU-1] = mtu;
 240                         dst_set_expires(dst, dn_rt_mtu_expires);
 241                 }
 242                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 243                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 244                         if (dst_metric(dst, RTAX_ADVMSS) > mss)
 245                                 dst->metrics[RTAX_ADVMSS-1] = mss;
 246                 }
 247         }
 248 }
 249
 250 /*
 251  * When a route has been marked obsolete. (e.g. routing cache flush)
 252  */
 253 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 254 {
 255         return NULL;
 256 }
 257
 258 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 259 {
 260         dst_release(dst);
 261         return NULL;
 262 }
 263
 264 static void dn_dst_link_failure(struct sk_buff *skb)
 265 {
 266         return;
 267 }
 268
 269 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
 270 {
 271         return ((fl1->nl_u.dn_u.daddr ^ fl2->nl_u.dn_u.daddr) |
 272                 (fl1->nl_u.dn_u.saddr ^ fl2->nl_u.dn_u.saddr) |
 273                 (fl1->mark ^ fl2->mark) |
 274                 (fl1->nl_u.dn_u.scope ^ fl2->nl_u.dn_u.scope) |
 275                 (fl1->oif ^ fl2->oif) |
 276                 (fl1->iif ^ fl2->iif)) == 0;
 277 }
 278
 279 static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
 280 {
 281         struct dn_route *rth, **rthp;
 282         unsigned long now = jiffies;
 283
 284         rthp = &dn_rt_hash_table[hash].chain;
 285
 286         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 287         while((rth = *rthp) != NULL) {
 288                 if (compare_keys(&rth->fl, &rt->fl)) {
 289                         /* Put it first */
 290                         *rthp = rth->u.dst.dn_next;
 291                         rcu_assign_pointer(rth->u.dst.dn_next,
 292                                            dn_rt_hash_table[hash].chain);
 293                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 294
 295                         dst_use(&rth->u.dst, now);
 296                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 297
 298                         dnrt_drop(rt);
 299                         *rp = rth;
 300                         return 0;
 301                 }
 302                 rthp = &rth->u.dst.dn_next;
 303         }
 304
 305         rcu_assign_pointer(rt->u.dst.dn_next, dn_rt_hash_table[hash].chain);
 306         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 307
 308         dst_use(&rt->u.dst, now);
 309         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 310         *rp = rt;
 311         return 0;
 312 }
 313
 314 static 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.dst.dn_next;
 327                         rt->u.dst.dn_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
 384         /* Add back headers */
 385         skb_push(skb, skb->data - skb_network_header(skb));
 386
 387         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 388                 return NET_RX_DROP;
 389
 390         cb = DN_SKB_CB(skb);
 391         /* Skip packet length and point to flags */
 392         ptr = skb->data + 2;
 393         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 394
 395         dst = (__le16 *)ptr;
 396         ptr += 2;
 397         src = (__le16 *)ptr;
 398         ptr += 2;
 399         *ptr = 0; /* Zero hop count */
 400
 401         swap(*src, *dst);
 402
 403         skb->pkt_type = PACKET_OUTGOING;
 404         dn_rt_finish_output(skb, NULL, NULL);
 405         return NET_RX_SUCCESS;
 406 }
 407
 408 /**
 409  * dn_return_long - Return a long packet to its sender
 410  * @skb: The long format packet to return
 411  *
 412  */
 413 static int dn_return_long(struct sk_buff *skb)
 414 {
 415         struct dn_skb_cb *cb;
 416         unsigned char *ptr;
 417         unsigned char *src_addr, *dst_addr;
 418         unsigned char tmp[ETH_ALEN];
 419
 420         /* Add back all headers */
 421         skb_push(skb, skb->data - skb_network_header(skb));
 422
 423         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 424                 return NET_RX_DROP;
 425
 426         cb = DN_SKB_CB(skb);
 427         /* Ignore packet length and point to flags */
 428         ptr = skb->data + 2;
 429
 430         /* Skip padding */
 431         if (*ptr & DN_RT_F_PF) {
 432                 char padlen = (*ptr & ~DN_RT_F_PF);
 433                 ptr += padlen;
 434         }
 435
 436         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 437         ptr += 2;
 438         dst_addr = ptr;
 439         ptr += 8;
 440         src_addr = ptr;
 441         ptr += 6;
 442         *ptr = 0; /* Zero hop count */
 443
 444         /* Swap source and destination */
 445         memcpy(tmp, src_addr, ETH_ALEN);
 446         memcpy(src_addr, dst_addr, ETH_ALEN);
 447         memcpy(dst_addr, tmp, ETH_ALEN);
 448
 449         skb->pkt_type = PACKET_OUTGOING;
 450         dn_rt_finish_output(skb, dst_addr, src_addr);
 451         return NET_RX_SUCCESS;
 452 }
 453
 454 /**
 455  * dn_route_rx_packet - Try and find a route for an incoming packet
 456  * @skb: The packet to find a route for
 457  *
 458  * Returns: result of input function if route is found, error code otherwise
 459  */
 460 static int dn_route_rx_packet(struct sk_buff *skb)
 461 {
 462         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 463         int err;
 464
 465         if ((err = dn_route_input(skb)) == 0)
 466                 return dst_input(skb);
 467
 468         if (decnet_debug_level & 4) {
 469                 char *devname = skb->dev ? skb->dev->name : "???";
 470                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 471                 printk(KERN_DEBUG
 472                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 473                         (int)cb->rt_flags, devname, skb->len,
 474                         le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
 475                         err, skb->pkt_type);
 476         }
 477
 478         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 479                 switch(cb->rt_flags & DN_RT_PKT_MSK) {
 480                         case DN_RT_PKT_SHORT:
 481                                 return dn_return_short(skb);
 482                         case DN_RT_PKT_LONG:
 483                                 return dn_return_long(skb);
 484                 }
 485         }
 486
 487         kfree_skb(skb);
 488         return NET_RX_DROP;
 489 }
 490
 491 static int dn_route_rx_long(struct sk_buff *skb)
 492 {
 493         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 494         unsigned char *ptr = skb->data;
 495
 496         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 497                 goto drop_it;
 498
 499         skb_pull(skb, 20);
 500         skb_reset_transport_header(skb);
 501
 502         /* Destination info */
 503         ptr += 2;
 504         cb->dst = dn_eth2dn(ptr);
 505         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 506                 goto drop_it;
 507         ptr += 6;
 508
 509
 510         /* Source info */
 511         ptr += 2;
 512         cb->src = dn_eth2dn(ptr);
 513         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 514                 goto drop_it;
 515         ptr += 6;
 516         /* Other junk */
 517         ptr++;
 518         cb->hops = *ptr++; /* Visit Count */
 519
 520         return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
 521
 522 drop_it:
 523         kfree_skb(skb);
 524         return NET_RX_DROP;
 525 }
 526
 527
 528
 529 static int dn_route_rx_short(struct sk_buff *skb)
 530 {
 531         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 532         unsigned char *ptr = skb->data;
 533
 534         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 535                 goto drop_it;
 536
 537         skb_pull(skb, 5);
 538         skb_reset_transport_header(skb);
 539
 540         cb->dst = *(__le16 *)ptr;
 541         ptr += 2;
 542         cb->src = *(__le16 *)ptr;
 543         ptr += 2;
 544         cb->hops = *ptr & 0x3f;
 545
 546         return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
 547
 548 drop_it:
 549         kfree_skb(skb);
 550         return NET_RX_DROP;
 551 }
 552
 553 static int dn_route_discard(struct sk_buff *skb)
 554 {
 555         /*
 556          * I know we drop the packet here, but thats considered success in
 557          * this case
 558          */
 559         kfree_skb(skb);
 560         return NET_RX_SUCCESS;
 561 }
 562
 563 static int dn_route_ptp_hello(struct sk_buff *skb)
 564 {
 565         dn_dev_hello(skb);
 566         dn_neigh_pointopoint_hello(skb);
 567         return NET_RX_SUCCESS;
 568 }
 569
 570 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 571 {
 572         struct dn_skb_cb *cb;
 573         unsigned char flags = 0;
 574         __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 575         struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
 576         unsigned char padlen = 0;
 577
 578         if (!net_eq(dev_net(dev), &init_net))
 579                 goto dump_it;
 580
 581         if (dn == NULL)
 582                 goto dump_it;
 583
 584         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 585                 goto out;
 586
 587         if (!pskb_may_pull(skb, 3))
 588                 goto dump_it;
 589
 590         skb_pull(skb, 2);
 591
 592         if (len > skb->len)
 593                 goto dump_it;
 594
 595         skb_trim(skb, len);
 596
 597         flags = *skb->data;
 598
 599         cb = DN_SKB_CB(skb);
 600         cb->stamp = jiffies;
 601         cb->iif = dev->ifindex;
 602
 603         /*
 604          * If we have padding, remove it.
 605          */
 606         if (flags & DN_RT_F_PF) {
 607                 padlen = flags & ~DN_RT_F_PF;
 608                 if (!pskb_may_pull(skb, padlen + 1))
 609                         goto dump_it;
 610                 skb_pull(skb, padlen);
 611                 flags = *skb->data;
 612         }
 613
 614         skb_reset_network_header(skb);
 615
 616         /*
 617          * Weed out future version DECnet
 618          */
 619         if (flags & DN_RT_F_VER)
 620                 goto dump_it;
 621
 622         cb->rt_flags = flags;
 623
 624         if (decnet_debug_level & 1)
 625                 printk(KERN_DEBUG
 626                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 627                         (int)flags, (dev) ? dev->name : "???", len, skb->len,
 628                         padlen);
 629
 630         if (flags & DN_RT_PKT_CNTL) {
 631                 if (unlikely(skb_linearize(skb)))
 632                         goto dump_it;
 633
 634                 switch(flags & DN_RT_CNTL_MSK) {
 635                         case DN_RT_PKT_INIT:
 636                                 dn_dev_init_pkt(skb);
 637                                 break;
 638                         case DN_RT_PKT_VERI:
 639                                 dn_dev_veri_pkt(skb);
 640                                 break;
 641                 }
 642
 643                 if (dn->parms.state != DN_DEV_S_RU)
 644                         goto dump_it;
 645
 646                 switch(flags & DN_RT_CNTL_MSK) {
 647                         case DN_RT_PKT_HELO:
 648                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_route_ptp_hello);
 649
 650                         case DN_RT_PKT_L1RT:
 651                         case DN_RT_PKT_L2RT:
 652                                 return NF_HOOK(PF_DECnet, NF_DN_ROUTE, skb, skb->dev, NULL, dn_route_discard);
 653                         case DN_RT_PKT_ERTH:
 654                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_router_hello);
 655
 656                         case DN_RT_PKT_EEDH:
 657                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_endnode_hello);
 658                 }
 659         } else {
 660                 if (dn->parms.state != DN_DEV_S_RU)
 661                         goto dump_it;
 662
 663                 skb_pull(skb, 1); /* Pull flags */
 664
 665                 switch(flags & DN_RT_PKT_MSK) {
 666                         case DN_RT_PKT_LONG:
 667                                 return dn_route_rx_long(skb);
 668                         case DN_RT_PKT_SHORT:
 669                                 return dn_route_rx_short(skb);
 670                 }
 671         }
 672
 673 dump_it:
 674         kfree_skb(skb);
 675 out:
 676         return NET_RX_DROP;
 677 }
 678
 679 static int dn_output(struct sk_buff *skb)
 680 {
 681         struct dst_entry *dst = skb->dst;
 682         struct dn_route *rt = (struct dn_route *)dst;
 683         struct net_device *dev = dst->dev;
 684         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 685         struct neighbour *neigh;
 686
 687         int err = -EINVAL;
 688
 689         if ((neigh = dst->neighbour) == NULL)
 690                 goto error;
 691
 692         skb->dev = dev;
 693
 694         cb->src = rt->rt_saddr;
 695         cb->dst = rt->rt_daddr;
 696
 697         /*
 698          * Always set the Intra-Ethernet bit on all outgoing packets
 699          * originated on this node. Only valid flag from upper layers
 700          * is return-to-sender-requested. Set hop count to 0 too.
 701          */
 702         cb->rt_flags &= ~DN_RT_F_RQR;
 703         cb->rt_flags |= DN_RT_F_IE;
 704         cb->hops = 0;
 705
 706         return NF_HOOK(PF_DECnet, NF_DN_LOCAL_OUT, skb, NULL, dev, neigh->output);
 707
 708 error:
 709         if (net_ratelimit())
 710                 printk(KERN_DEBUG "dn_output: This should not happen\n");
 711
 712         kfree_skb(skb);
 713
 714         return err;
 715 }
 716
 717 static int dn_forward(struct sk_buff *skb)
 718 {
 719         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 720         struct dst_entry *dst = skb->dst;
 721         struct dn_dev *dn_db = dst->dev->dn_ptr;
 722         struct dn_route *rt;
 723         struct neighbour *neigh = dst->neighbour;
 724         int header_len;
 725 #ifdef CONFIG_NETFILTER
 726         struct net_device *dev = skb->dev;
 727 #endif
 728
 729         if (skb->pkt_type != PACKET_HOST)
 730                 goto drop;
 731
 732         /* Ensure that we have enough space for headers */
 733         rt = (struct dn_route *)skb->dst;
 734         header_len = dn_db->use_long ? 21 : 6;
 735         if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+header_len))
 736                 goto drop;
 737
 738         /*
 739          * Hop count exceeded.
 740          */
 741         if (++cb->hops > 30)
 742                 goto drop;
 743
 744         skb->dev = rt->u.dst.dev;
 745
 746         /*
 747          * If packet goes out same interface it came in on, then set
 748          * the Intra-Ethernet bit. This has no effect for short
 749          * packets, so we don't need to test for them here.
 750          */
 751         cb->rt_flags &= ~DN_RT_F_IE;
 752         if (rt->rt_flags & RTCF_DOREDIRECT)
 753                 cb->rt_flags |= DN_RT_F_IE;
 754
 755         return NF_HOOK(PF_DECnet, NF_DN_FORWARD, skb, dev, skb->dev, neigh->output);
 756
 757 drop:
 758         kfree_skb(skb);
 759         return NET_RX_DROP;
 760 }
 761
 762 /*
 763  * Used to catch bugs. This should never normally get
 764  * called.
 765  */
 766 static int dn_rt_bug(struct sk_buff *skb)
 767 {
 768         if (net_ratelimit()) {
 769                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 770
 771                 printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
 772                                 le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 773         }
 774
 775         kfree_skb(skb);
 776
 777         return NET_RX_BAD;
 778 }
 779
 780 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 781 {
 782         struct dn_fib_info *fi = res->fi;
 783         struct net_device *dev = rt->u.dst.dev;
 784         struct neighbour *n;
 785         unsigned mss;
 786
 787         if (fi) {
 788                 if (DN_FIB_RES_GW(*res) &&
 789                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 790                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 791                 memcpy(rt->u.dst.metrics, fi->fib_metrics,
 792                        sizeof(rt->u.dst.metrics));
 793         }
 794         rt->rt_type = res->type;
 795
 796         if (dev != NULL && rt->u.dst.neighbour == NULL) {
 797                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 798                 if (IS_ERR(n))
 799                         return PTR_ERR(n);
 800                 rt->u.dst.neighbour = n;
 801         }
 802
 803         if (dst_metric(&rt->u.dst, RTAX_MTU) == 0 ||
 804             dst_metric(&rt->u.dst, RTAX_MTU) > rt->u.dst.dev->mtu)
 805                 rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
 806         mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->u.dst));
 807         if (dst_metric(&rt->u.dst, RTAX_ADVMSS) == 0 ||
 808             dst_metric(&rt->u.dst, RTAX_ADVMSS) > mss)
 809                 rt->u.dst.metrics[RTAX_ADVMSS-1] = mss;
 810         return 0;
 811 }
 812
 813 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 814 {
 815         __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 816         int match = 16;
 817         while(tmp) {
 818                 tmp >>= 1;
 819                 match--;
 820         }
 821         return match;
 822 }
 823
 824 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 825 {
 826         __le16 saddr = 0;
 827         struct dn_dev *dn_db = dev->dn_ptr;
 828         struct dn_ifaddr *ifa;
 829         int best_match = 0;
 830         int ret;
 831
 832         read_lock(&dev_base_lock);
 833         for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
 834                 if (ifa->ifa_scope > scope)
 835                         continue;
 836                 if (!daddr) {
 837                         saddr = ifa->ifa_local;
 838                         break;
 839                 }
 840                 ret = dn_match_addr(daddr, ifa->ifa_local);
 841                 if (ret > best_match)
 842                         saddr = ifa->ifa_local;
 843                 if (best_match == 0)
 844                         saddr = ifa->ifa_local;
 845         }
 846         read_unlock(&dev_base_lock);
 847
 848         return saddr;
 849 }
 850
 851 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 852 {
 853         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 854 }
 855
 856 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 857 {
 858         __le16 mask = dnet_make_mask(res->prefixlen);
 859         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 860 }
 861
 862 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
 863 {
 864         struct flowi fl = { .nl_u = { .dn_u =
 865                                       { .daddr = oldflp->fld_dst,
 866                                         .saddr = oldflp->fld_src,
 867                                         .scope = RT_SCOPE_UNIVERSE,
 868                                      } },
 869                             .mark = oldflp->mark,
 870                             .iif = init_net.loopback_dev->ifindex,
 871                             .oif = oldflp->oif };
 872         struct dn_route *rt = NULL;
 873         struct net_device *dev_out = NULL, *dev;
 874         struct neighbour *neigh = NULL;
 875         unsigned hash;
 876         unsigned flags = 0;
 877         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 878         int err;
 879         int free_res = 0;
 880         __le16 gateway = 0;
 881
 882         if (decnet_debug_level & 16)
 883                 printk(KERN_DEBUG
 884                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 885                        " iif=%d oif=%d\n", le16_to_cpu(oldflp->fld_dst),
 886                        le16_to_cpu(oldflp->fld_src),
 887                        oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);
 888
 889         /* If we have an output interface, verify its a DECnet device */
 890         if (oldflp->oif) {
 891                 dev_out = dev_get_by_index(&init_net, oldflp->oif);
 892                 err = -ENODEV;
 893                 if (dev_out && dev_out->dn_ptr == NULL) {
 894                         dev_put(dev_out);
 895                         dev_out = NULL;
 896                 }
 897                 if (dev_out == NULL)
 898                         goto out;
 899         }
 900
 901         /* If we have a source address, verify that its a local address */
 902         if (oldflp->fld_src) {
 903                 err = -EADDRNOTAVAIL;
 904
 905                 if (dev_out) {
 906                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
 907                                 goto source_ok;
 908                         dev_put(dev_out);
 909                         goto out;
 910                 }
 911                 read_lock(&dev_base_lock);
 912                 for_each_netdev(&init_net, dev) {
 913                         if (!dev->dn_ptr)
 914                                 continue;
 915                         if (!dn_dev_islocal(dev, oldflp->fld_src))
 916                                 continue;
 917                         if ((dev->flags & IFF_LOOPBACK) &&
 918                             oldflp->fld_dst &&
 919                             !dn_dev_islocal(dev, oldflp->fld_dst))
 920                                 continue;
 921
 922                         dev_out = dev;
 923                         break;
 924                 }
 925                 read_unlock(&dev_base_lock);
 926                 if (dev_out == NULL)
 927                         goto out;
 928                 dev_hold(dev_out);
 929 source_ok:
 930                 ;
 931         }
 932
 933         /* No destination? Assume its local */
 934         if (!fl.fld_dst) {
 935                 fl.fld_dst = fl.fld_src;
 936
 937                 err = -EADDRNOTAVAIL;
 938                 if (dev_out)
 939                         dev_put(dev_out);
 940                 dev_out = init_net.loopback_dev;
 941                 dev_hold(dev_out);
 942                 if (!fl.fld_dst) {
 943                         fl.fld_dst =
 944                         fl.fld_src = dnet_select_source(dev_out, 0,
 945                                                        RT_SCOPE_HOST);
 946                         if (!fl.fld_dst)
 947                                 goto out;
 948                 }
 949                 fl.oif = init_net.loopback_dev->ifindex;
 950                 res.type = RTN_LOCAL;
 951                 goto make_route;
 952         }
 953
 954         if (decnet_debug_level & 16)
 955                 printk(KERN_DEBUG
 956                        "dn_route_output_slow: initial checks complete."
 957                        " dst=%o4x src=%04x oif=%d try_hard=%d\n",
 958                        le16_to_cpu(fl.fld_dst), le16_to_cpu(fl.fld_src),
 959                        fl.oif, try_hard);
 960
 961         /*
 962          * N.B. If the kernel is compiled without router support then
 963          * dn_fib_lookup() will evaluate to non-zero so this if () block
 964          * will always be executed.
 965          */
 966         err = -ESRCH;
 967         if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
 968                 struct dn_dev *dn_db;
 969                 if (err != -ESRCH)
 970                         goto out;
 971                 /*
 972                  * Here the fallback is basically the standard algorithm for
 973                  * routing in endnodes which is described in the DECnet routing
 974                  * docs
 975                  *
 976                  * If we are not trying hard, look in neighbour cache.
 977                  * The result is tested to ensure that if a specific output
 978                  * device/source address was requested, then we honour that
 979                  * here
 980                  */
 981                 if (!try_hard) {
 982                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fl.fld_dst);
 983                         if (neigh) {
 984                                 if ((oldflp->oif &&
 985                                     (neigh->dev->ifindex != oldflp->oif)) ||
 986                                     (oldflp->fld_src &&
 987                                     (!dn_dev_islocal(neigh->dev,
 988                                                       oldflp->fld_src)))) {
 989                                         neigh_release(neigh);
 990                                         neigh = NULL;
 991                                 } else {
 992                                         if (dev_out)
 993                                                 dev_put(dev_out);
 994                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
 995                                                 dev_out = init_net.loopback_dev;
 996                                                 res.type = RTN_LOCAL;
 997                                         } else {
 998                                                 dev_out = neigh->dev;
 999                                         }
1000                                         dev_hold(dev_out);
1001                                         goto select_source;
1002                                 }
1003                         }
1004                 }
1005
1006                 /* Not there? Perhaps its a local address */
1007                 if (dev_out == NULL)
1008                         dev_out = dn_dev_get_default();
1009                 err = -ENODEV;
1010                 if (dev_out == NULL)
1011                         goto out;
1012                 dn_db = dev_out->dn_ptr;
1013                 /* Possible improvement - check all devices for local addr */
1014                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1015                         dev_put(dev_out);
1016                         dev_out = init_net.loopback_dev;
1017                         dev_hold(dev_out);
1018                         res.type = RTN_LOCAL;
1019                         goto select_source;
1020                 }
1021                 /* Not local either.... try sending it to the default router */
1022                 neigh = neigh_clone(dn_db->router);
1023                 BUG_ON(neigh && neigh->dev != dev_out);
1024
1025                 /* Ok then, we assume its directly connected and move on */
1026 select_source:
1027                 if (neigh)
1028                         gateway = ((struct dn_neigh *)neigh)->addr;
1029                 if (gateway == 0)
1030                         gateway = fl.fld_dst;
1031                 if (fl.fld_src == 0) {
1032                         fl.fld_src = dnet_select_source(dev_out, gateway,
1033                                                          res.type == RTN_LOCAL ?
1034                                                          RT_SCOPE_HOST :
1035                                                          RT_SCOPE_LINK);
1036                         if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1037                                 goto e_addr;
1038                 }
1039                 fl.oif = dev_out->ifindex;
1040                 goto make_route;
1041         }
1042         free_res = 1;
1043
1044         if (res.type == RTN_NAT)
1045                 goto e_inval;
1046
1047         if (res.type == RTN_LOCAL) {
1048                 if (!fl.fld_src)
1049                         fl.fld_src = fl.fld_dst;
1050                 if (dev_out)
1051                         dev_put(dev_out);
1052                 dev_out = init_net.loopback_dev;
1053                 dev_hold(dev_out);
1054                 fl.oif = dev_out->ifindex;
1055                 if (res.fi)
1056                         dn_fib_info_put(res.fi);
1057                 res.fi = NULL;
1058                 goto make_route;
1059         }
1060
1061         if (res.fi->fib_nhs > 1 && fl.oif == 0)
1062                 dn_fib_select_multipath(&fl, &res);
1063
1064         /*
1065          * We could add some logic to deal with default routes here and
1066          * get rid of some of the special casing above.
1067          */
1068
1069         if (!fl.fld_src)
1070                 fl.fld_src = DN_FIB_RES_PREFSRC(res);
1071
1072         if (dev_out)
1073                 dev_put(dev_out);
1074         dev_out = DN_FIB_RES_DEV(res);
1075         dev_hold(dev_out);
1076         fl.oif = dev_out->ifindex;
1077         gateway = DN_FIB_RES_GW(res);
1078
1079 make_route:
1080         if (dev_out->flags & IFF_LOOPBACK)
1081                 flags |= RTCF_LOCAL;
1082
1083         rt = dst_alloc(&dn_dst_ops);
1084         if (rt == NULL)
1085                 goto e_nobufs;
1086
1087         atomic_set(&rt->u.dst.__refcnt, 1);
1088         rt->u.dst.flags   = DST_HOST;
1089
1090         rt->fl.fld_src    = oldflp->fld_src;
1091         rt->fl.fld_dst    = oldflp->fld_dst;
1092         rt->fl.oif        = oldflp->oif;
1093         rt->fl.iif        = 0;
1094         rt->fl.mark       = oldflp->mark;
1095
1096         rt->rt_saddr      = fl.fld_src;
1097         rt->rt_daddr      = fl.fld_dst;
1098         rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1099         rt->rt_local_src  = fl.fld_src;
1100
1101         rt->rt_dst_map    = fl.fld_dst;
1102         rt->rt_src_map    = fl.fld_src;
1103
1104         rt->u.dst.dev = dev_out;
1105         dev_hold(dev_out);
1106         rt->u.dst.neighbour = neigh;
1107         neigh = NULL;
1108
1109         rt->u.dst.lastuse = jiffies;
1110         rt->u.dst.output  = dn_output;
1111         rt->u.dst.input   = dn_rt_bug;
1112         rt->rt_flags      = flags;
1113         if (flags & RTCF_LOCAL)
1114                 rt->u.dst.input = dn_nsp_rx;
1115
1116         err = dn_rt_set_next_hop(rt, &res);
1117         if (err)
1118                 goto e_neighbour;
1119
1120         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1121         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1122
1123 done:
1124         if (neigh)
1125                 neigh_release(neigh);
1126         if (free_res)
1127                 dn_fib_res_put(&res);
1128         if (dev_out)
1129                 dev_put(dev_out);
1130 out:
1131         return err;
1132
1133 e_addr:
1134         err = -EADDRNOTAVAIL;
1135         goto done;
1136 e_inval:
1137         err = -EINVAL;
1138         goto done;
1139 e_nobufs:
1140         err = -ENOBUFS;
1141         goto done;
1142 e_neighbour:
1143         dst_free(&rt->u.dst);
1144         goto e_nobufs;
1145 }
1146
1147
1148 /*
1149  * N.B. The flags may be moved into the flowi at some future stage.
1150  */
1151 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1152 {
1153         unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1154         struct dn_route *rt = NULL;
1155
1156         if (!(flags & MSG_TRYHARD)) {
1157                 rcu_read_lock_bh();
1158                 for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt;
1159                         rt = rcu_dereference(rt->u.dst.dn_next)) {
1160                         if ((flp->fld_dst == rt->fl.fld_dst) &&
1161                             (flp->fld_src == rt->fl.fld_src) &&
1162                             (flp->mark == rt->fl.mark) &&
1163                             (rt->fl.iif == 0) &&
1164                             (rt->fl.oif == flp->oif)) {
1165                                 dst_use(&rt->u.dst, jiffies);
1166                                 rcu_read_unlock_bh();
1167                                 *pprt = &rt->u.dst;
1168                                 return 0;
1169                         }
1170                 }
1171                 rcu_read_unlock_bh();
1172         }
1173
1174         return dn_route_output_slow(pprt, flp, flags);
1175 }
1176
1177 static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
1178 {
1179         int err;
1180
1181         err = __dn_route_output_key(pprt, flp, flags);
1182         if (err == 0 && flp->proto) {
1183                 err = xfrm_lookup(&init_net, pprt, flp, NULL, 0);
1184         }
1185         return err;
1186 }
1187
1188 int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
1189 {
1190         int err;
1191
1192         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1193         if (err == 0 && fl->proto) {
1194                 err = xfrm_lookup(&init_net, pprt, fl, sk,
1195                                  (flags & MSG_DONTWAIT) ? 0 : XFRM_LOOKUP_WAIT);
1196         }
1197         return err;
1198 }
1199
1200 static int dn_route_input_slow(struct sk_buff *skb)
1201 {
1202         struct dn_route *rt = NULL;
1203         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1204         struct net_device *in_dev = skb->dev;
1205         struct net_device *out_dev = NULL;
1206         struct dn_dev *dn_db;
1207         struct neighbour *neigh = NULL;
1208         unsigned hash;
1209         int flags = 0;
1210         __le16 gateway = 0;
1211         __le16 local_src = 0;
1212         struct flowi fl = { .nl_u = { .dn_u =
1213                                      { .daddr = cb->dst,
1214                                        .saddr = cb->src,
1215                                        .scope = RT_SCOPE_UNIVERSE,
1216                                     } },
1217                             .mark = skb->mark,
1218                             .iif = skb->dev->ifindex };
1219         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1220         int err = -EINVAL;
1221         int free_res = 0;
1222
1223         dev_hold(in_dev);
1224
1225         if ((dn_db = in_dev->dn_ptr) == NULL)
1226                 goto out;
1227
1228         /* Zero source addresses are not allowed */
1229         if (fl.fld_src == 0)
1230                 goto out;
1231
1232         /*
1233          * In this case we've just received a packet from a source
1234          * outside ourselves pretending to come from us. We don't
1235          * allow it any further to prevent routing loops, spoofing and
1236          * other nasties. Loopback packets already have the dst attached
1237          * so this only affects packets which have originated elsewhere.
1238          */
1239         err  = -ENOTUNIQ;
1240         if (dn_dev_islocal(in_dev, cb->src))
1241                 goto out;
1242
1243         err = dn_fib_lookup(&fl, &res);
1244         if (err) {
1245                 if (err != -ESRCH)
1246                         goto out;
1247                 /*
1248                  * Is the destination us ?
1249                  */
1250                 if (!dn_dev_islocal(in_dev, cb->dst))
1251                         goto e_inval;
1252
1253                 res.type = RTN_LOCAL;
1254         } else {
1255                 __le16 src_map = fl.fld_src;
1256                 free_res = 1;
1257
1258                 out_dev = DN_FIB_RES_DEV(res);
1259                 if (out_dev == NULL) {
1260                         if (net_ratelimit())
1261                                 printk(KERN_CRIT "Bug in dn_route_input_slow() "
1262                                                  "No output device\n");
1263                         goto e_inval;
1264                 }
1265                 dev_hold(out_dev);
1266
1267                 if (res.r)
1268                         src_map = fl.fld_src; /* no NAT support for now */
1269
1270                 gateway = DN_FIB_RES_GW(res);
1271                 if (res.type == RTN_NAT) {
1272                         fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1273                         dn_fib_res_put(&res);
1274                         free_res = 0;
1275                         if (dn_fib_lookup(&fl, &res))
1276                                 goto e_inval;
1277                         free_res = 1;
1278                         if (res.type != RTN_UNICAST)
1279                                 goto e_inval;
1280                         flags |= RTCF_DNAT;
1281                         gateway = fl.fld_dst;
1282                 }
1283                 fl.fld_src = src_map;
1284         }
1285
1286         switch(res.type) {
1287         case RTN_UNICAST:
1288                 /*
1289                  * Forwarding check here, we only check for forwarding
1290                  * being turned off, if you want to only forward intra
1291                  * area, its up to you to set the routing tables up
1292                  * correctly.
1293                  */
1294                 if (dn_db->parms.forwarding == 0)
1295                         goto e_inval;
1296
1297                 if (res.fi->fib_nhs > 1 && fl.oif == 0)
1298                         dn_fib_select_multipath(&fl, &res);
1299
1300                 /*
1301                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1302                  * flag as a hint to set the intra-ethernet bit when
1303                  * forwarding. If we've got NAT in operation, we don't do
1304                  * this optimisation.
1305                  */
1306                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1307                         flags |= RTCF_DOREDIRECT;
1308
1309                 local_src = DN_FIB_RES_PREFSRC(res);
1310
1311         case RTN_BLACKHOLE:
1312         case RTN_UNREACHABLE:
1313                 break;
1314         case RTN_LOCAL:
1315                 flags |= RTCF_LOCAL;
1316                 fl.fld_src = cb->dst;
1317                 fl.fld_dst = cb->src;
1318
1319                 /* Routing tables gave us a gateway */
1320                 if (gateway)
1321                         goto make_route;
1322
1323                 /* Packet was intra-ethernet, so we know its on-link */
1324                 if (cb->rt_flags & DN_RT_F_IE) {
1325                         gateway = cb->src;
1326                         flags |= RTCF_DIRECTSRC;
1327                         goto make_route;
1328                 }
1329
1330                 /* Use the default router if there is one */
1331                 neigh = neigh_clone(dn_db->router);
1332                 if (neigh) {
1333                         gateway = ((struct dn_neigh *)neigh)->addr;
1334                         goto make_route;
1335                 }
1336
1337                 /* Close eyes and pray */
1338                 gateway = cb->src;
1339                 flags |= RTCF_DIRECTSRC;
1340                 goto make_route;
1341         default:
1342                 goto e_inval;
1343         }
1344
1345 make_route:
1346         rt = dst_alloc(&dn_dst_ops);
1347         if (rt == NULL)
1348                 goto e_nobufs;
1349
1350         rt->rt_saddr      = fl.fld_src;
1351         rt->rt_daddr      = fl.fld_dst;
1352         rt->rt_gateway    = fl.fld_dst;
1353         if (gateway)
1354                 rt->rt_gateway = gateway;
1355         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1356
1357         rt->rt_dst_map    = fl.fld_dst;
1358         rt->rt_src_map    = fl.fld_src;
1359
1360         rt->fl.fld_src    = cb->src;
1361         rt->fl.fld_dst    = cb->dst;
1362         rt->fl.oif        = 0;
1363         rt->fl.iif        = in_dev->ifindex;
1364         rt->fl.mark       = fl.mark;
1365
1366         rt->u.dst.flags = DST_HOST;
1367         rt->u.dst.neighbour = neigh;
1368         rt->u.dst.dev = out_dev;
1369         rt->u.dst.lastuse = jiffies;
1370         rt->u.dst.output = dn_rt_bug;
1371         switch(res.type) {
1372                 case RTN_UNICAST:
1373                         rt->u.dst.input = dn_forward;
1374                         break;
1375                 case RTN_LOCAL:
1376                         rt->u.dst.output = dn_output;
1377                         rt->u.dst.input = dn_nsp_rx;
1378                         rt->u.dst.dev = in_dev;
1379                         flags |= RTCF_LOCAL;
1380                         break;
1381                 default:
1382                 case RTN_UNREACHABLE:
1383                 case RTN_BLACKHOLE:
1384                         rt->u.dst.input = dst_discard;
1385         }
1386         rt->rt_flags = flags;
1387         if (rt->u.dst.dev)
1388                 dev_hold(rt->u.dst.dev);
1389
1390         err = dn_rt_set_next_hop(rt, &res);
1391         if (err)
1392                 goto e_neighbour;
1393
1394         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1395         dn_insert_route(rt, hash, (struct dn_route **)&skb->dst);
1396
1397 done:
1398         if (neigh)
1399                 neigh_release(neigh);
1400         if (free_res)
1401                 dn_fib_res_put(&res);
1402         dev_put(in_dev);
1403         if (out_dev)
1404                 dev_put(out_dev);
1405 out:
1406         return err;
1407
1408 e_inval:
1409         err = -EINVAL;
1410         goto done;
1411
1412 e_nobufs:
1413         err = -ENOBUFS;
1414         goto done;
1415
1416 e_neighbour:
1417         dst_free(&rt->u.dst);
1418         goto done;
1419 }
1420
1421 static int dn_route_input(struct sk_buff *skb)
1422 {
1423         struct dn_route *rt;
1424         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1425         unsigned hash = dn_hash(cb->src, cb->dst);
1426
1427         if (skb->dst)
1428                 return 0;
1429
1430         rcu_read_lock();
1431         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1432             rt = rcu_dereference(rt->u.dst.dn_next)) {
1433                 if ((rt->fl.fld_src == cb->src) &&
1434                     (rt->fl.fld_dst == cb->dst) &&
1435                     (rt->fl.oif == 0) &&
1436                     (rt->fl.mark == skb->mark) &&
1437                     (rt->fl.iif == cb->iif)) {
1438                         dst_use(&rt->u.dst, jiffies);
1439                         rcu_read_unlock();
1440                         skb->dst = (struct dst_entry *)rt;
1441                         return 0;
1442                 }
1443         }
1444         rcu_read_unlock();
1445
1446         return dn_route_input_slow(skb);
1447 }
1448
1449 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1450                            int event, int nowait, unsigned int flags)
1451 {
1452         struct dn_route *rt = (struct dn_route *)skb->dst;
1453         struct rtmsg *r;
1454         struct nlmsghdr *nlh;
1455         unsigned char *b = skb_tail_pointer(skb);
1456         long expires;
1457
1458         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1459         r = NLMSG_DATA(nlh);
1460         r->rtm_family = AF_DECnet;
1461         r->rtm_dst_len = 16;
1462         r->rtm_src_len = 0;
1463         r->rtm_tos = 0;
1464         r->rtm_table = RT_TABLE_MAIN;
1465         RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
1466         r->rtm_type = rt->rt_type;
1467         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1468         r->rtm_scope = RT_SCOPE_UNIVERSE;
1469         r->rtm_protocol = RTPROT_UNSPEC;
1470         if (rt->rt_flags & RTCF_NOTIFY)
1471                 r->rtm_flags |= RTM_F_NOTIFY;
1472         RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1473         if (rt->fl.fld_src) {
1474                 r->rtm_src_len = 16;
1475                 RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1476         }
1477         if (rt->u.dst.dev)
1478                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
1479         /*
1480          * Note to self - change this if input routes reverse direction when
1481          * they deal only with inputs and not with replies like they do
1482          * currently.
1483          */
1484         RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1485         if (rt->rt_daddr != rt->rt_gateway)
1486                 RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1487         if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
1488                 goto rtattr_failure;
1489         expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
1490         if (rtnl_put_cacheinfo(skb, &rt->u.dst, 0, 0, 0, expires,
1491                                rt->u.dst.error) < 0)
1492                 goto rtattr_failure;
1493         if (rt->fl.iif)
1494                 RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1495
1496         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1497         return skb->len;
1498
1499 nlmsg_failure:
1500 rtattr_failure:
1501         nlmsg_trim(skb, b);
1502         return -1;
1503 }
1504
1505 /*
1506  * This is called by both endnodes and routers now.
1507  */
1508 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1509 {
1510         struct net *net = sock_net(in_skb->sk);
1511         struct rtattr **rta = arg;
1512         struct rtmsg *rtm = NLMSG_DATA(nlh);
1513         struct dn_route *rt = NULL;
1514         struct dn_skb_cb *cb;
1515         int err;
1516         struct sk_buff *skb;
1517         struct flowi fl;
1518
1519         if (net != &init_net)
1520                 return -EINVAL;
1521
1522         memset(&fl, 0, sizeof(fl));
1523         fl.proto = DNPROTO_NSP;
1524
1525         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1526         if (skb == NULL)
1527                 return -ENOBUFS;
1528         skb_reset_mac_header(skb);
1529         cb = DN_SKB_CB(skb);
1530
1531         if (rta[RTA_SRC-1])
1532                 memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1533         if (rta[RTA_DST-1])
1534                 memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1535         if (rta[RTA_IIF-1])
1536                 memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1537
1538         if (fl.iif) {
1539                 struct net_device *dev;
1540                 if ((dev = dev_get_by_index(&init_net, fl.iif)) == NULL) {
1541                         kfree_skb(skb);
1542                         return -ENODEV;
1543                 }
1544                 if (!dev->dn_ptr) {
1545                         dev_put(dev);
1546                         kfree_skb(skb);
1547                         return -ENODEV;
1548                 }
1549                 skb->protocol = htons(ETH_P_DNA_RT);
1550                 skb->dev = dev;
1551                 cb->src = fl.fld_src;
1552                 cb->dst = fl.fld_dst;
1553                 local_bh_disable();
1554                 err = dn_route_input(skb);
1555                 local_bh_enable();
1556                 memset(cb, 0, sizeof(struct dn_skb_cb));
1557                 rt = (struct dn_route *)skb->dst;
1558                 if (!err && -rt->u.dst.error)
1559                         err = rt->u.dst.error;
1560         } else {
1561                 int oif = 0;
1562                 if (rta[RTA_OIF - 1])
1563                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1564                 fl.oif = oif;
1565                 err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1566         }
1567
1568         if (skb->dev)
1569                 dev_put(skb->dev);
1570         skb->dev = NULL;
1571         if (err)
1572                 goto out_free;
1573         skb->dst = &rt->u.dst;
1574         if (rtm->rtm_flags & RTM_F_NOTIFY)
1575                 rt->rt_flags |= RTCF_NOTIFY;
1576
1577         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1578
1579         if (err == 0)
1580                 goto out_free;
1581         if (err < 0) {
1582                 err = -EMSGSIZE;
1583                 goto out_free;
1584         }
1585
1586         return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
1587
1588 out_free:
1589         kfree_skb(skb);
1590         return err;
1591 }
1592
1593 /*
1594  * For routers, this is called from dn_fib_dump, but for endnodes its
1595  * called directly from the rtnetlink dispatch table.
1596  */
1597 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1598 {
1599         struct net *net = sock_net(skb->sk);
1600         struct dn_route *rt;
1601         int h, s_h;
1602         int idx, s_idx;
1603
1604         if (net != &init_net)
1605                 return 0;
1606
1607         if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1608                 return -EINVAL;
1609         if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1610                 return 0;
1611
1612         s_h = cb->args[0];
1613         s_idx = idx = cb->args[1];
1614         for(h = 0; h <= dn_rt_hash_mask; h++) {
1615                 if (h < s_h)
1616                         continue;
1617                 if (h > s_h)
1618                         s_idx = 0;
1619                 rcu_read_lock_bh();
1620                 for(rt = rcu_dereference(dn_rt_hash_table[h].chain), idx = 0;
1621                         rt;
1622                         rt = rcu_dereference(rt->u.dst.dn_next), idx++) {
1623                         if (idx < s_idx)
1624                                 continue;
1625                         skb->dst = dst_clone(&rt->u.dst);
1626                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1627                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1628                                         1, NLM_F_MULTI) <= 0) {
1629                                 dst_release(xchg(&skb->dst, NULL));
1630                                 rcu_read_unlock_bh();
1631                                 goto done;
1632                         }
1633                         dst_release(xchg(&skb->dst, NULL));
1634                 }
1635                 rcu_read_unlock_bh();
1636         }
1637
1638 done:
1639         cb->args[0] = h;
1640         cb->args[1] = idx;
1641         return skb->len;
1642 }
1643
1644 #ifdef CONFIG_PROC_FS
1645 struct dn_rt_cache_iter_state {
1646         int bucket;
1647 };
1648
1649 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1650 {
1651         struct dn_route *rt = NULL;
1652         struct dn_rt_cache_iter_state *s = seq->private;
1653
1654         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1655                 rcu_read_lock_bh();
1656                 rt = dn_rt_hash_table[s->bucket].chain;
1657                 if (rt)
1658                         break;
1659                 rcu_read_unlock_bh();
1660         }
1661         return rcu_dereference(rt);
1662 }
1663
1664 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1665 {
1666         struct dn_rt_cache_iter_state *s = seq->private;
1667
1668         rt = rt->u.dst.dn_next;
1669         while(!rt) {
1670                 rcu_read_unlock_bh();
1671                 if (--s->bucket < 0)
1672                         break;
1673                 rcu_read_lock_bh();
1674                 rt = dn_rt_hash_table[s->bucket].chain;
1675         }
1676         return rcu_dereference(rt);
1677 }
1678
1679 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1680 {
1681         struct dn_route *rt = dn_rt_cache_get_first(seq);
1682
1683         if (rt) {
1684                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1685                         --*pos;
1686         }
1687         return *pos ? NULL : rt;
1688 }
1689
1690 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1691 {
1692         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1693         ++*pos;
1694         return rt;
1695 }
1696
1697 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1698 {
1699         if (v)
1700                 rcu_read_unlock_bh();
1701 }
1702
1703 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1704 {
1705         struct dn_route *rt = v;
1706         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1707
1708         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1709                         rt->u.dst.dev ? rt->u.dst.dev->name : "*",
1710                         dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1711                         dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1712                         atomic_read(&rt->u.dst.__refcnt),
1713                         rt->u.dst.__use,
1714                         (int) dst_metric(&rt->u.dst, RTAX_RTT));
1715         return 0;
1716 }
1717
1718 static const struct seq_operations dn_rt_cache_seq_ops = {
1719         .start  = dn_rt_cache_seq_start,
1720         .next   = dn_rt_cache_seq_next,
1721         .stop   = dn_rt_cache_seq_stop,
1722         .show   = dn_rt_cache_seq_show,
1723 };
1724
1725 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1726 {
1727         return seq_open_private(file, &dn_rt_cache_seq_ops,
1728                         sizeof(struct dn_rt_cache_iter_state));
1729 }
1730
1731 static const struct file_operations dn_rt_cache_seq_fops = {
1732         .owner   = THIS_MODULE,
1733         .open    = dn_rt_cache_seq_open,
1734         .read    = seq_read,
1735         .llseek  = seq_lseek,
1736         .release = seq_release_private,
1737 };
1738
1739 #endif /* CONFIG_PROC_FS */
1740
1741 void __init dn_route_init(void)
1742 {
1743         int i, goal, order;
1744
1745         dn_dst_ops.kmem_cachep =
1746                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1747                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1748         setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1749         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1750         add_timer(&dn_route_timer);
1751
1752         goal = num_physpages >> (26 - PAGE_SHIFT);
1753
1754         for(order = 0; (1UL << order) < goal; order++)
1755                 /* NOTHING */;
1756
1757         /*
1758          * Only want 1024 entries max, since the table is very, very unlikely
1759          * to be larger than that.
1760          */
1761         while(order && ((((1UL << order) * PAGE_SIZE) /
1762                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1763                 order--;
1764
1765         do {
1766                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1767                         sizeof(struct dn_rt_hash_bucket);
1768                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1769                         dn_rt_hash_mask--;
1770                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1771                         __get_free_pages(GFP_ATOMIC, order);
1772         } while (dn_rt_hash_table == NULL && --order > 0);
1773
1774         if (!dn_rt_hash_table)
1775                 panic("Failed to allocate DECnet route cache hash table\n");
1776
1777         printk(KERN_INFO
1778                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1779                 dn_rt_hash_mask,
1780                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1781
1782         dn_rt_hash_mask--;
1783         for(i = 0; i <= dn_rt_hash_mask; i++) {
1784                 spin_lock_init(&dn_rt_hash_table[i].lock);
1785                 dn_rt_hash_table[i].chain = NULL;
1786         }
1787
1788         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1789
1790         proc_net_fops_create(&init_net, "decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1791
1792 #ifdef CONFIG_DECNET_ROUTER
1793         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute, dn_fib_dump);
1794 #else
1795         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1796                       dn_cache_dump);
1797 #endif
1798 }
1799
1800 void __exit dn_route_cleanup(void)
1801 {
1802         del_timer(&dn_route_timer);
1803         dn_run_flush(0);
1804
1805         proc_net_remove(&init_net, "decnet_cache");
1806 }
1807