net/decnet/dn_route.c

   1 /*
   2  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   3  *              operating system.  DECnet is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              DECnet Routing Functions (Endnode and Router)
   7  *
   8  * Authors:     Steve Whitehouse <SteveW@ACM.org>
   9  *              Eduardo Marcelo Serrat <emserrat@geocities.com>
  10  *
  11  * Changes:
  12  *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
  13  *                                 "return-to-sender" bits on outgoing
  14  *                                 packets.
  15  *              Steve Whitehouse : Timeouts for cached routes.
  16  *              Steve Whitehouse : Use dst cache for input routes too.
  17  *              Steve Whitehouse : Fixed error values in dn_send_skb.
  18  *              Steve Whitehouse : Rework routing functions to better fit
  19  *                                 DECnet routing design
  20  *              Alexey Kuznetsov : New SMP locking
  21  *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
  22  *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
  23  *                                 Fixed possible skb leak in rtnetlink funcs.
  24  *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
  25  *                                 Alexey Kuznetsov's finer grained locking
  26  *                                 from ipv4/route.c.
  27  *              Steve Whitehouse : Routing is now starting to look like a
  28  *                                 sensible set of code now, mainly due to
  29  *                                 my copying the IPv4 routing code. The
  30  *                                 hooks here are modified and will continue
  31  *                                 to evolve for a while.
  32  *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
  33  *                                 stuff. Look out raw sockets your days
  34  *                                 are numbered!
  35  *              Steve Whitehouse : Added return-to-sender functions. Added
  36  *                                 backlog congestion level return codes.
  37  *              Steve Whitehouse : Fixed bug where routes were set up with
  38  *                                 no ref count on net devices.
  39  *              Steve Whitehouse : RCU for the route cache
  40  *              Steve Whitehouse : Preparations for the flow cache
  41  *              Steve Whitehouse : Prepare for nonlinear skbs
  42  */
  43
  44 /******************************************************************************
  45     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
  46
  47     This program is free software; you can redistribute it and/or modify
  48     it under the terms of the GNU General Public License as published by
  49     the Free Software Foundation; either version 2 of the License, or
  50     any later version.
  51
  52     This program is distributed in the hope that it will be useful,
  53     but WITHOUT ANY WARRANTY; without even the implied warranty of
  54     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  55     GNU General Public License for more details.
  56 *******************************************************************************/
  57
  58 #include <linux/errno.h>
  59 #include <linux/types.h>
  60 #include <linux/socket.h>
  61 #include <linux/in.h>
  62 #include <linux/kernel.h>
  63 #include <linux/sockios.h>
  64 #include <linux/net.h>
  65 #include <linux/netdevice.h>
  66 #include <linux/inet.h>
  67 #include <linux/route.h>
  68 #include <linux/in_route.h>
  69 #include <linux/slab.h>
  70 #include <net/sock.h>
  71 #include <linux/mm.h>
  72 #include <linux/proc_fs.h>
  73 #include <linux/seq_file.h>
  74 #include <linux/init.h>
  75 #include <linux/rtnetlink.h>
  76 #include <linux/string.h>
  77 #include <linux/netfilter_decnet.h>
  78 #include <linux/rcupdate.h>
  79 #include <linux/times.h>
  80 #include <asm/errno.h>
  81 #include <net/net_namespace.h>
  82 #include <net/netlink.h>
  83 #include <net/neighbour.h>
  84 #include <net/dst.h>
  85 #include <net/flow.h>
  86 #include <net/fib_rules.h>
  87 #include <net/dn.h>
  88 #include <net/dn_dev.h>
  89 #include <net/dn_nsp.h>
  90 #include <net/dn_route.h>
  91 #include <net/dn_neigh.h>
  92 #include <net/dn_fib.h>
  93
  94 struct dn_rt_hash_bucket
  95 {
  96         struct dn_route *chain;
  97         spinlock_t lock;
  98 };
  99
 100 extern struct neigh_table dn_neigh_table;
 101
 102
 103 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 104
 105 static const int dn_rt_min_delay = 2 * HZ;
 106 static const int dn_rt_max_delay = 10 * HZ;
 107 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 108
 109 static unsigned long dn_rt_deadline;
 110
 111 static int dn_dst_gc(struct dst_ops *ops);
 112 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 113 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 114 static void dn_dst_link_failure(struct sk_buff *);
 115 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
 116 static int dn_route_input(struct sk_buff *);
 117 static void dn_run_flush(unsigned long dummy);
 118
 119 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 120 static unsigned dn_rt_hash_mask;
 121
 122 static struct timer_list dn_route_timer;
 123 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 124 int decnet_dst_gc_interval = 2;
 125
 126 static struct dst_ops dn_dst_ops = {
 127         .family =               PF_DECnet,
 128         .protocol =             cpu_to_be16(ETH_P_DNA_RT),
 129         .gc_thresh =            128,
 130         .gc =                   dn_dst_gc,
 131         .check =                dn_dst_check,
 132         .negative_advice =      dn_dst_negative_advice,
 133         .link_failure =         dn_dst_link_failure,
 134         .update_pmtu =          dn_dst_update_pmtu,
 135 };
 136
 137 static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
 138 {
 139         __u16 tmp = (__u16 __force)(src ^ dst);
 140         tmp ^= (tmp >> 3);
 141         tmp ^= (tmp >> 5);
 142         tmp ^= (tmp >> 10);
 143         return dn_rt_hash_mask & (unsigned)tmp;
 144 }
 145
 146 static inline void dnrt_free(struct dn_route *rt)
 147 {
 148         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 149 }
 150
 151 static inline void dnrt_drop(struct dn_route *rt)
 152 {
 153         dst_release(&rt->dst);
 154         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 155 }
 156
 157 static void dn_dst_check_expire(unsigned long dummy)
 158 {
 159         int i;
 160         struct dn_route *rt, **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->dst.__refcnt) ||
 170                                         (now - rt->dst.lastuse) < expire) {
 171                                 rtp = &rt->dst.dn_next;
 172                                 continue;
 173                         }
 174                         *rtp = rt->dst.dn_next;
 175                         rt->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->dst.__refcnt) ||
 201                                         (now - rt->dst.lastuse) < expire) {
 202                                 rtp = &rt->dst.dn_next;
 203                                 continue;
 204                         }
 205                         *rtp = rt->dst.dn_next;
 206                         rt->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 }
 267
 268 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
 269 {
 270         return ((fl1->nl_u.dn_u.daddr ^ fl2->nl_u.dn_u.daddr) |
 271                 (fl1->nl_u.dn_u.saddr ^ fl2->nl_u.dn_u.saddr) |
 272                 (fl1->mark ^ fl2->mark) |
 273                 (fl1->nl_u.dn_u.scope ^ fl2->nl_u.dn_u.scope) |
 274                 (fl1->oif ^ fl2->oif) |
 275                 (fl1->iif ^ fl2->iif)) == 0;
 276 }
 277
 278 static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
 279 {
 280         struct dn_route *rth, **rthp;
 281         unsigned long now = jiffies;
 282
 283         rthp = &dn_rt_hash_table[hash].chain;
 284
 285         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 286         while((rth = *rthp) != NULL) {
 287                 if (compare_keys(&rth->fl, &rt->fl)) {
 288                         /* Put it first */
 289                         *rthp = rth->dst.dn_next;
 290                         rcu_assign_pointer(rth->dst.dn_next,
 291                                            dn_rt_hash_table[hash].chain);
 292                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 293
 294                         dst_use(&rth->dst, now);
 295                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 296
 297                         dnrt_drop(rt);
 298                         *rp = rth;
 299                         return 0;
 300                 }
 301                 rthp = &rth->dst.dn_next;
 302         }
 303
 304         rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain);
 305         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 306
 307         dst_use(&rt->dst, now);
 308         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 309         *rp = rt;
 310         return 0;
 311 }
 312
 313 static void dn_run_flush(unsigned long dummy)
 314 {
 315         int i;
 316         struct dn_route *rt, *next;
 317
 318         for(i = 0; i < dn_rt_hash_mask; i++) {
 319                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 320
 321                 if ((rt = xchg(&dn_rt_hash_table[i].chain, NULL)) == NULL)
 322                         goto nothing_to_declare;
 323
 324                 for(; rt; rt=next) {
 325                         next = rt->dst.dn_next;
 326                         rt->dst.dn_next = NULL;
 327                         dst_free((struct dst_entry *)rt);
 328                 }
 329
 330 nothing_to_declare:
 331                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 332         }
 333 }
 334
 335 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 336
 337 void dn_rt_cache_flush(int delay)
 338 {
 339         unsigned long now = jiffies;
 340         int user_mode = !in_interrupt();
 341
 342         if (delay < 0)
 343                 delay = dn_rt_min_delay;
 344
 345         spin_lock_bh(&dn_rt_flush_lock);
 346
 347         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 348                 long tmo = (long)(dn_rt_deadline - now);
 349
 350                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 351                         tmo = 0;
 352
 353                 if (delay > tmo)
 354                         delay = tmo;
 355         }
 356
 357         if (delay <= 0) {
 358                 spin_unlock_bh(&dn_rt_flush_lock);
 359                 dn_run_flush(0);
 360                 return;
 361         }
 362
 363         if (dn_rt_deadline == 0)
 364                 dn_rt_deadline = now + dn_rt_max_delay;
 365
 366         dn_rt_flush_timer.expires = now + delay;
 367         add_timer(&dn_rt_flush_timer);
 368         spin_unlock_bh(&dn_rt_flush_lock);
 369 }
 370
 371 /**
 372  * dn_return_short - Return a short packet to its sender
 373  * @skb: The packet to return
 374  *
 375  */
 376 static int dn_return_short(struct sk_buff *skb)
 377 {
 378         struct dn_skb_cb *cb;
 379         unsigned char *ptr;
 380         __le16 *src;
 381         __le16 *dst;
 382
 383         /* Add back headers */
 384         skb_push(skb, skb->data - skb_network_header(skb));
 385
 386         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 387                 return NET_RX_DROP;
 388
 389         cb = DN_SKB_CB(skb);
 390         /* Skip packet length and point to flags */
 391         ptr = skb->data + 2;
 392         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 393
 394         dst = (__le16 *)ptr;
 395         ptr += 2;
 396         src = (__le16 *)ptr;
 397         ptr += 2;
 398         *ptr = 0; /* Zero hop count */
 399
 400         swap(*src, *dst);
 401
 402         skb->pkt_type = PACKET_OUTGOING;
 403         dn_rt_finish_output(skb, NULL, NULL);
 404         return NET_RX_SUCCESS;
 405 }
 406
 407 /**
 408  * dn_return_long - Return a long packet to its sender
 409  * @skb: The long format packet to return
 410  *
 411  */
 412 static int dn_return_long(struct sk_buff *skb)
 413 {
 414         struct dn_skb_cb *cb;
 415         unsigned char *ptr;
 416         unsigned char *src_addr, *dst_addr;
 417         unsigned char tmp[ETH_ALEN];
 418
 419         /* Add back all headers */
 420         skb_push(skb, skb->data - skb_network_header(skb));
 421
 422         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 423                 return NET_RX_DROP;
 424
 425         cb = DN_SKB_CB(skb);
 426         /* Ignore packet length and point to flags */
 427         ptr = skb->data + 2;
 428
 429         /* Skip padding */
 430         if (*ptr & DN_RT_F_PF) {
 431                 char padlen = (*ptr & ~DN_RT_F_PF);
 432                 ptr += padlen;
 433         }
 434
 435         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 436         ptr += 2;
 437         dst_addr = ptr;
 438         ptr += 8;
 439         src_addr = ptr;
 440         ptr += 6;
 441         *ptr = 0; /* Zero hop count */
 442
 443         /* Swap source and destination */
 444         memcpy(tmp, src_addr, ETH_ALEN);
 445         memcpy(src_addr, dst_addr, ETH_ALEN);
 446         memcpy(dst_addr, tmp, ETH_ALEN);
 447
 448         skb->pkt_type = PACKET_OUTGOING;
 449         dn_rt_finish_output(skb, dst_addr, src_addr);
 450         return NET_RX_SUCCESS;
 451 }
 452
 453 /**
 454  * dn_route_rx_packet - Try and find a route for an incoming packet
 455  * @skb: The packet to find a route for
 456  *
 457  * Returns: result of input function if route is found, error code otherwise
 458  */
 459 static int dn_route_rx_packet(struct sk_buff *skb)
 460 {
 461         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 462         int err;
 463
 464         if ((err = dn_route_input(skb)) == 0)
 465                 return dst_input(skb);
 466
 467         if (decnet_debug_level & 4) {
 468                 char *devname = skb->dev ? skb->dev->name : "???";
 469                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 470                 printk(KERN_DEBUG
 471                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 472                         (int)cb->rt_flags, devname, skb->len,
 473                         le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
 474                         err, skb->pkt_type);
 475         }
 476
 477         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 478                 switch(cb->rt_flags & DN_RT_PKT_MSK) {
 479                         case DN_RT_PKT_SHORT:
 480                                 return dn_return_short(skb);
 481                         case DN_RT_PKT_LONG:
 482                                 return dn_return_long(skb);
 483                 }
 484         }
 485
 486         kfree_skb(skb);
 487         return NET_RX_DROP;
 488 }
 489
 490 static int dn_route_rx_long(struct sk_buff *skb)
 491 {
 492         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 493         unsigned char *ptr = skb->data;
 494
 495         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 496                 goto drop_it;
 497
 498         skb_pull(skb, 20);
 499         skb_reset_transport_header(skb);
 500
 501         /* Destination info */
 502         ptr += 2;
 503         cb->dst = dn_eth2dn(ptr);
 504         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 505                 goto drop_it;
 506         ptr += 6;
 507
 508
 509         /* Source info */
 510         ptr += 2;
 511         cb->src = dn_eth2dn(ptr);
 512         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 513                 goto drop_it;
 514         ptr += 6;
 515         /* Other junk */
 516         ptr++;
 517         cb->hops = *ptr++; /* Visit Count */
 518
 519         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 520                        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(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 547                        dn_route_rx_packet);
 548
 549 drop_it:
 550         kfree_skb(skb);
 551         return NET_RX_DROP;
 552 }
 553
 554 static int dn_route_discard(struct sk_buff *skb)
 555 {
 556         /*
 557          * I know we drop the packet here, but thats considered success in
 558          * this case
 559          */
 560         kfree_skb(skb);
 561         return NET_RX_SUCCESS;
 562 }
 563
 564 static int dn_route_ptp_hello(struct sk_buff *skb)
 565 {
 566         dn_dev_hello(skb);
 567         dn_neigh_pointopoint_hello(skb);
 568         return NET_RX_SUCCESS;
 569 }
 570
 571 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 572 {
 573         struct dn_skb_cb *cb;
 574         unsigned char flags = 0;
 575         __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 576         struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
 577         unsigned char padlen = 0;
 578
 579         if (!net_eq(dev_net(dev), &init_net))
 580                 goto dump_it;
 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_reset_network_header(skb);
 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(NFPROTO_DECNET, NF_DN_HELLO,
 650                                                skb, skb->dev, NULL,
 651                                                dn_route_ptp_hello);
 652
 653                         case DN_RT_PKT_L1RT:
 654                         case DN_RT_PKT_L2RT:
 655                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
 656                                                skb, skb->dev, NULL,
 657                                                dn_route_discard);
 658                         case DN_RT_PKT_ERTH:
 659                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 660                                                skb, skb->dev, NULL,
 661                                                dn_neigh_router_hello);
 662
 663                         case DN_RT_PKT_EEDH:
 664                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 665                                                skb, skb->dev, NULL,
 666                                                dn_neigh_endnode_hello);
 667                 }
 668         } else {
 669                 if (dn->parms.state != DN_DEV_S_RU)
 670                         goto dump_it;
 671
 672                 skb_pull(skb, 1); /* Pull flags */
 673
 674                 switch(flags & DN_RT_PKT_MSK) {
 675                         case DN_RT_PKT_LONG:
 676                                 return dn_route_rx_long(skb);
 677                         case DN_RT_PKT_SHORT:
 678                                 return dn_route_rx_short(skb);
 679                 }
 680         }
 681
 682 dump_it:
 683         kfree_skb(skb);
 684 out:
 685         return NET_RX_DROP;
 686 }
 687
 688 static int dn_output(struct sk_buff *skb)
 689 {
 690         struct dst_entry *dst = skb_dst(skb);
 691         struct dn_route *rt = (struct dn_route *)dst;
 692         struct net_device *dev = dst->dev;
 693         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 694         struct neighbour *neigh;
 695
 696         int err = -EINVAL;
 697
 698         if ((neigh = dst->neighbour) == NULL)
 699                 goto error;
 700
 701         skb->dev = dev;
 702
 703         cb->src = rt->rt_saddr;
 704         cb->dst = rt->rt_daddr;
 705
 706         /*
 707          * Always set the Intra-Ethernet bit on all outgoing packets
 708          * originated on this node. Only valid flag from upper layers
 709          * is return-to-sender-requested. Set hop count to 0 too.
 710          */
 711         cb->rt_flags &= ~DN_RT_F_RQR;
 712         cb->rt_flags |= DN_RT_F_IE;
 713         cb->hops = 0;
 714
 715         return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, skb, NULL, dev,
 716                        neigh->output);
 717
 718 error:
 719         if (net_ratelimit())
 720                 printk(KERN_DEBUG "dn_output: This should not happen\n");
 721
 722         kfree_skb(skb);
 723
 724         return err;
 725 }
 726
 727 static int dn_forward(struct sk_buff *skb)
 728 {
 729         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 730         struct dst_entry *dst = skb_dst(skb);
 731         struct dn_dev *dn_db = dst->dev->dn_ptr;
 732         struct dn_route *rt;
 733         struct neighbour *neigh = dst->neighbour;
 734         int header_len;
 735 #ifdef CONFIG_NETFILTER
 736         struct net_device *dev = skb->dev;
 737 #endif
 738
 739         if (skb->pkt_type != PACKET_HOST)
 740                 goto drop;
 741
 742         /* Ensure that we have enough space for headers */
 743         rt = (struct dn_route *)skb_dst(skb);
 744         header_len = dn_db->use_long ? 21 : 6;
 745         if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
 746                 goto drop;
 747
 748         /*
 749          * Hop count exceeded.
 750          */
 751         if (++cb->hops > 30)
 752                 goto drop;
 753
 754         skb->dev = rt->dst.dev;
 755
 756         /*
 757          * If packet goes out same interface it came in on, then set
 758          * the Intra-Ethernet bit. This has no effect for short
 759          * packets, so we don't need to test for them here.
 760          */
 761         cb->rt_flags &= ~DN_RT_F_IE;
 762         if (rt->rt_flags & RTCF_DOREDIRECT)
 763                 cb->rt_flags |= DN_RT_F_IE;
 764
 765         return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, skb, dev, skb->dev,
 766                        neigh->output);
 767
 768 drop:
 769         kfree_skb(skb);
 770         return NET_RX_DROP;
 771 }
 772
 773 /*
 774  * Used to catch bugs. This should never normally get
 775  * called.
 776  */
 777 static int dn_rt_bug(struct sk_buff *skb)
 778 {
 779         if (net_ratelimit()) {
 780                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 781
 782                 printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
 783                                 le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 784         }
 785
 786         kfree_skb(skb);
 787
 788         return NET_RX_DROP;
 789 }
 790
 791 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 792 {
 793         struct dn_fib_info *fi = res->fi;
 794         struct net_device *dev = rt->dst.dev;
 795         struct neighbour *n;
 796         unsigned mss;
 797
 798         if (fi) {
 799                 if (DN_FIB_RES_GW(*res) &&
 800                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 801                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 802                 memcpy(rt->dst.metrics, fi->fib_metrics,
 803                        sizeof(rt->dst.metrics));
 804         }
 805         rt->rt_type = res->type;
 806
 807         if (dev != NULL && rt->dst.neighbour == NULL) {
 808                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 809                 if (IS_ERR(n))
 810                         return PTR_ERR(n);
 811                 rt->dst.neighbour = n;
 812         }
 813
 814         if (dst_metric(&rt->dst, RTAX_MTU) == 0 ||
 815             dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
 816                 rt->dst.metrics[RTAX_MTU-1] = rt->dst.dev->mtu;
 817         mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
 818         if (dst_metric(&rt->dst, RTAX_ADVMSS) == 0 ||
 819             dst_metric(&rt->dst, RTAX_ADVMSS) > mss)
 820                 rt->dst.metrics[RTAX_ADVMSS-1] = mss;
 821         return 0;
 822 }
 823
 824 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 825 {
 826         __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 827         int match = 16;
 828         while(tmp) {
 829                 tmp >>= 1;
 830                 match--;
 831         }
 832         return match;
 833 }
 834
 835 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 836 {
 837         __le16 saddr = 0;
 838         struct dn_dev *dn_db = dev->dn_ptr;
 839         struct dn_ifaddr *ifa;
 840         int best_match = 0;
 841         int ret;
 842
 843         read_lock(&dev_base_lock);
 844         for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
 845                 if (ifa->ifa_scope > scope)
 846                         continue;
 847                 if (!daddr) {
 848                         saddr = ifa->ifa_local;
 849                         break;
 850                 }
 851                 ret = dn_match_addr(daddr, ifa->ifa_local);
 852                 if (ret > best_match)
 853                         saddr = ifa->ifa_local;
 854                 if (best_match == 0)
 855                         saddr = ifa->ifa_local;
 856         }
 857         read_unlock(&dev_base_lock);
 858
 859         return saddr;
 860 }
 861
 862 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 863 {
 864         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 865 }
 866
 867 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 868 {
 869         __le16 mask = dnet_make_mask(res->prefixlen);
 870         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 871 }
 872
 873 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
 874 {
 875         struct flowi fl = { .nl_u = { .dn_u =
 876                                       { .daddr = oldflp->fld_dst,
 877                                         .saddr = oldflp->fld_src,
 878                                         .scope = RT_SCOPE_UNIVERSE,
 879                                      } },
 880                             .mark = oldflp->mark,
 881                             .iif = init_net.loopback_dev->ifindex,
 882                             .oif = oldflp->oif };
 883         struct dn_route *rt = NULL;
 884         struct net_device *dev_out = NULL, *dev;
 885         struct neighbour *neigh = NULL;
 886         unsigned hash;
 887         unsigned flags = 0;
 888         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 889         int err;
 890         int free_res = 0;
 891         __le16 gateway = 0;
 892
 893         if (decnet_debug_level & 16)
 894                 printk(KERN_DEBUG
 895                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 896                        " iif=%d oif=%d\n", le16_to_cpu(oldflp->fld_dst),
 897                        le16_to_cpu(oldflp->fld_src),
 898                        oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);
 899
 900         /* If we have an output interface, verify its a DECnet device */
 901         if (oldflp->oif) {
 902                 dev_out = dev_get_by_index(&init_net, oldflp->oif);
 903                 err = -ENODEV;
 904                 if (dev_out && dev_out->dn_ptr == NULL) {
 905                         dev_put(dev_out);
 906                         dev_out = NULL;
 907                 }
 908                 if (dev_out == NULL)
 909                         goto out;
 910         }
 911
 912         /* If we have a source address, verify that its a local address */
 913         if (oldflp->fld_src) {
 914                 err = -EADDRNOTAVAIL;
 915
 916                 if (dev_out) {
 917                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
 918                                 goto source_ok;
 919                         dev_put(dev_out);
 920                         goto out;
 921                 }
 922                 rcu_read_lock();
 923                 for_each_netdev_rcu(&init_net, dev) {
 924                         if (!dev->dn_ptr)
 925                                 continue;
 926                         if (!dn_dev_islocal(dev, oldflp->fld_src))
 927                                 continue;
 928                         if ((dev->flags & IFF_LOOPBACK) &&
 929                             oldflp->fld_dst &&
 930                             !dn_dev_islocal(dev, oldflp->fld_dst))
 931                                 continue;
 932
 933                         dev_out = dev;
 934                         break;
 935                 }
 936                 rcu_read_unlock();
 937                 if (dev_out == NULL)
 938                         goto out;
 939                 dev_hold(dev_out);
 940 source_ok:
 941                 ;
 942         }
 943
 944         /* No destination? Assume its local */
 945         if (!fl.fld_dst) {
 946                 fl.fld_dst = fl.fld_src;
 947
 948                 err = -EADDRNOTAVAIL;
 949                 if (dev_out)
 950                         dev_put(dev_out);
 951                 dev_out = init_net.loopback_dev;
 952                 dev_hold(dev_out);
 953                 if (!fl.fld_dst) {
 954                         fl.fld_dst =
 955                         fl.fld_src = dnet_select_source(dev_out, 0,
 956                                                        RT_SCOPE_HOST);
 957                         if (!fl.fld_dst)
 958                                 goto out;
 959                 }
 960                 fl.oif = init_net.loopback_dev->ifindex;
 961                 res.type = RTN_LOCAL;
 962                 goto make_route;
 963         }
 964
 965         if (decnet_debug_level & 16)
 966                 printk(KERN_DEBUG
 967                        "dn_route_output_slow: initial checks complete."
 968                        " dst=%o4x src=%04x oif=%d try_hard=%d\n",
 969                        le16_to_cpu(fl.fld_dst), le16_to_cpu(fl.fld_src),
 970                        fl.oif, try_hard);
 971
 972         /*
 973          * N.B. If the kernel is compiled without router support then
 974          * dn_fib_lookup() will evaluate to non-zero so this if () block
 975          * will always be executed.
 976          */
 977         err = -ESRCH;
 978         if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
 979                 struct dn_dev *dn_db;
 980                 if (err != -ESRCH)
 981                         goto out;
 982                 /*
 983                  * Here the fallback is basically the standard algorithm for
 984                  * routing in endnodes which is described in the DECnet routing
 985                  * docs
 986                  *
 987                  * If we are not trying hard, look in neighbour cache.
 988                  * The result is tested to ensure that if a specific output
 989                  * device/source address was requested, then we honour that
 990                  * here
 991                  */
 992                 if (!try_hard) {
 993                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fl.fld_dst);
 994                         if (neigh) {
 995                                 if ((oldflp->oif &&
 996                                     (neigh->dev->ifindex != oldflp->oif)) ||
 997                                     (oldflp->fld_src &&
 998                                     (!dn_dev_islocal(neigh->dev,
 999                                                       oldflp->fld_src)))) {
1000                                         neigh_release(neigh);
1001                                         neigh = NULL;
1002                                 } else {
1003                                         if (dev_out)
1004                                                 dev_put(dev_out);
1005                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
1006                                                 dev_out = init_net.loopback_dev;
1007                                                 res.type = RTN_LOCAL;
1008                                         } else {
1009                                                 dev_out = neigh->dev;
1010                                         }
1011                                         dev_hold(dev_out);
1012                                         goto select_source;
1013                                 }
1014                         }
1015                 }
1016
1017                 /* Not there? Perhaps its a local address */
1018                 if (dev_out == NULL)
1019                         dev_out = dn_dev_get_default();
1020                 err = -ENODEV;
1021                 if (dev_out == NULL)
1022                         goto out;
1023                 dn_db = dev_out->dn_ptr;
1024                 /* Possible improvement - check all devices for local addr */
1025                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1026                         dev_put(dev_out);
1027                         dev_out = init_net.loopback_dev;
1028                         dev_hold(dev_out);
1029                         res.type = RTN_LOCAL;
1030                         goto select_source;
1031                 }
1032                 /* Not local either.... try sending it to the default router */
1033                 neigh = neigh_clone(dn_db->router);
1034                 BUG_ON(neigh && neigh->dev != dev_out);
1035
1036                 /* Ok then, we assume its directly connected and move on */
1037 select_source:
1038                 if (neigh)
1039                         gateway = ((struct dn_neigh *)neigh)->addr;
1040                 if (gateway == 0)
1041                         gateway = fl.fld_dst;
1042                 if (fl.fld_src == 0) {
1043                         fl.fld_src = dnet_select_source(dev_out, gateway,
1044                                                          res.type == RTN_LOCAL ?
1045                                                          RT_SCOPE_HOST :
1046                                                          RT_SCOPE_LINK);
1047                         if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1048                                 goto e_addr;
1049                 }
1050                 fl.oif = dev_out->ifindex;
1051                 goto make_route;
1052         }
1053         free_res = 1;
1054
1055         if (res.type == RTN_NAT)
1056                 goto e_inval;
1057
1058         if (res.type == RTN_LOCAL) {
1059                 if (!fl.fld_src)
1060                         fl.fld_src = fl.fld_dst;
1061                 if (dev_out)
1062                         dev_put(dev_out);
1063                 dev_out = init_net.loopback_dev;
1064                 dev_hold(dev_out);
1065                 fl.oif = dev_out->ifindex;
1066                 if (res.fi)
1067                         dn_fib_info_put(res.fi);
1068                 res.fi = NULL;
1069                 goto make_route;
1070         }
1071
1072         if (res.fi->fib_nhs > 1 && fl.oif == 0)
1073                 dn_fib_select_multipath(&fl, &res);
1074
1075         /*
1076          * We could add some logic to deal with default routes here and
1077          * get rid of some of the special casing above.
1078          */
1079
1080         if (!fl.fld_src)
1081                 fl.fld_src = DN_FIB_RES_PREFSRC(res);
1082
1083         if (dev_out)
1084                 dev_put(dev_out);
1085         dev_out = DN_FIB_RES_DEV(res);
1086         dev_hold(dev_out);
1087         fl.oif = dev_out->ifindex;
1088         gateway = DN_FIB_RES_GW(res);
1089
1090 make_route:
1091         if (dev_out->flags & IFF_LOOPBACK)
1092                 flags |= RTCF_LOCAL;
1093
1094         rt = dst_alloc(&dn_dst_ops);
1095         if (rt == NULL)
1096                 goto e_nobufs;
1097
1098         atomic_set(&rt->dst.__refcnt, 1);
1099         rt->dst.flags   = DST_HOST;
1100
1101         rt->fl.fld_src    = oldflp->fld_src;
1102         rt->fl.fld_dst    = oldflp->fld_dst;
1103         rt->fl.oif        = oldflp->oif;
1104         rt->fl.iif        = 0;
1105         rt->fl.mark       = oldflp->mark;
1106
1107         rt->rt_saddr      = fl.fld_src;
1108         rt->rt_daddr      = fl.fld_dst;
1109         rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1110         rt->rt_local_src  = fl.fld_src;
1111
1112         rt->rt_dst_map    = fl.fld_dst;
1113         rt->rt_src_map    = fl.fld_src;
1114
1115         rt->dst.dev = dev_out;
1116         dev_hold(dev_out);
1117         rt->dst.neighbour = neigh;
1118         neigh = NULL;
1119
1120         rt->dst.lastuse = jiffies;
1121         rt->dst.output  = dn_output;
1122         rt->dst.input   = dn_rt_bug;
1123         rt->rt_flags      = flags;
1124         if (flags & RTCF_LOCAL)
1125                 rt->dst.input = dn_nsp_rx;
1126
1127         err = dn_rt_set_next_hop(rt, &res);
1128         if (err)
1129                 goto e_neighbour;
1130
1131         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1132         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1133
1134 done:
1135         if (neigh)
1136                 neigh_release(neigh);
1137         if (free_res)
1138                 dn_fib_res_put(&res);
1139         if (dev_out)
1140                 dev_put(dev_out);
1141 out:
1142         return err;
1143
1144 e_addr:
1145         err = -EADDRNOTAVAIL;
1146         goto done;
1147 e_inval:
1148         err = -EINVAL;
1149         goto done;
1150 e_nobufs:
1151         err = -ENOBUFS;
1152         goto done;
1153 e_neighbour:
1154         dst_free(&rt->dst);
1155         goto e_nobufs;
1156 }
1157
1158
1159 /*
1160  * N.B. The flags may be moved into the flowi at some future stage.
1161  */
1162 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1163 {
1164         unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1165         struct dn_route *rt = NULL;
1166
1167         if (!(flags & MSG_TRYHARD)) {
1168                 rcu_read_lock_bh();
1169                 for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1170                         rt = rcu_dereference_bh(rt->dst.dn_next)) {
1171                         if ((flp->fld_dst == rt->fl.fld_dst) &&
1172                             (flp->fld_src == rt->fl.fld_src) &&
1173                             (flp->mark == rt->fl.mark) &&
1174                             (rt->fl.iif == 0) &&
1175                             (rt->fl.oif == flp->oif)) {
1176                                 dst_use(&rt->dst, jiffies);
1177                                 rcu_read_unlock_bh();
1178                                 *pprt = &rt->dst;
1179                                 return 0;
1180                         }
1181                 }
1182                 rcu_read_unlock_bh();
1183         }
1184
1185         return dn_route_output_slow(pprt, flp, flags);
1186 }
1187
1188 static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
1189 {
1190         int err;
1191
1192         err = __dn_route_output_key(pprt, flp, flags);
1193         if (err == 0 && flp->proto) {
1194                 err = xfrm_lookup(&init_net, pprt, flp, NULL, 0);
1195         }
1196         return err;
1197 }
1198
1199 int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
1200 {
1201         int err;
1202
1203         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1204         if (err == 0 && fl->proto) {
1205                 err = xfrm_lookup(&init_net, pprt, fl, sk,
1206                                  (flags & MSG_DONTWAIT) ? 0 : XFRM_LOOKUP_WAIT);
1207         }
1208         return err;
1209 }
1210
1211 static int dn_route_input_slow(struct sk_buff *skb)
1212 {
1213         struct dn_route *rt = NULL;
1214         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1215         struct net_device *in_dev = skb->dev;
1216         struct net_device *out_dev = NULL;
1217         struct dn_dev *dn_db;
1218         struct neighbour *neigh = NULL;
1219         unsigned hash;
1220         int flags = 0;
1221         __le16 gateway = 0;
1222         __le16 local_src = 0;
1223         struct flowi fl = { .nl_u = { .dn_u =
1224                                      { .daddr = cb->dst,
1225                                        .saddr = cb->src,
1226                                        .scope = RT_SCOPE_UNIVERSE,
1227                                     } },
1228                             .mark = skb->mark,
1229                             .iif = skb->dev->ifindex };
1230         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1231         int err = -EINVAL;
1232         int free_res = 0;
1233
1234         dev_hold(in_dev);
1235
1236         if ((dn_db = in_dev->dn_ptr) == NULL)
1237                 goto out;
1238
1239         /* Zero source addresses are not allowed */
1240         if (fl.fld_src == 0)
1241                 goto out;
1242
1243         /*
1244          * In this case we've just received a packet from a source
1245          * outside ourselves pretending to come from us. We don't
1246          * allow it any further to prevent routing loops, spoofing and
1247          * other nasties. Loopback packets already have the dst attached
1248          * so this only affects packets which have originated elsewhere.
1249          */
1250         err  = -ENOTUNIQ;
1251         if (dn_dev_islocal(in_dev, cb->src))
1252                 goto out;
1253
1254         err = dn_fib_lookup(&fl, &res);
1255         if (err) {
1256                 if (err != -ESRCH)
1257                         goto out;
1258                 /*
1259                  * Is the destination us ?
1260                  */
1261                 if (!dn_dev_islocal(in_dev, cb->dst))
1262                         goto e_inval;
1263
1264                 res.type = RTN_LOCAL;
1265         } else {
1266                 __le16 src_map = fl.fld_src;
1267                 free_res = 1;
1268
1269                 out_dev = DN_FIB_RES_DEV(res);
1270                 if (out_dev == NULL) {
1271                         if (net_ratelimit())
1272                                 printk(KERN_CRIT "Bug in dn_route_input_slow() "
1273                                                  "No output device\n");
1274                         goto e_inval;
1275                 }
1276                 dev_hold(out_dev);
1277
1278                 if (res.r)
1279                         src_map = fl.fld_src; /* no NAT support for now */
1280
1281                 gateway = DN_FIB_RES_GW(res);
1282                 if (res.type == RTN_NAT) {
1283                         fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1284                         dn_fib_res_put(&res);
1285                         free_res = 0;
1286                         if (dn_fib_lookup(&fl, &res))
1287                                 goto e_inval;
1288                         free_res = 1;
1289                         if (res.type != RTN_UNICAST)
1290                                 goto e_inval;
1291                         flags |= RTCF_DNAT;
1292                         gateway = fl.fld_dst;
1293                 }
1294                 fl.fld_src = src_map;
1295         }
1296
1297         switch(res.type) {
1298         case RTN_UNICAST:
1299                 /*
1300                  * Forwarding check here, we only check for forwarding
1301                  * being turned off, if you want to only forward intra
1302                  * area, its up to you to set the routing tables up
1303                  * correctly.
1304                  */
1305                 if (dn_db->parms.forwarding == 0)
1306                         goto e_inval;
1307
1308                 if (res.fi->fib_nhs > 1 && fl.oif == 0)
1309                         dn_fib_select_multipath(&fl, &res);
1310
1311                 /*
1312                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1313                  * flag as a hint to set the intra-ethernet bit when
1314                  * forwarding. If we've got NAT in operation, we don't do
1315                  * this optimisation.
1316                  */
1317                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1318                         flags |= RTCF_DOREDIRECT;
1319
1320                 local_src = DN_FIB_RES_PREFSRC(res);
1321
1322         case RTN_BLACKHOLE:
1323         case RTN_UNREACHABLE:
1324                 break;
1325         case RTN_LOCAL:
1326                 flags |= RTCF_LOCAL;
1327                 fl.fld_src = cb->dst;
1328                 fl.fld_dst = cb->src;
1329
1330                 /* Routing tables gave us a gateway */
1331                 if (gateway)
1332                         goto make_route;
1333
1334                 /* Packet was intra-ethernet, so we know its on-link */
1335                 if (cb->rt_flags & DN_RT_F_IE) {
1336                         gateway = cb->src;
1337                         flags |= RTCF_DIRECTSRC;
1338                         goto make_route;
1339                 }
1340
1341                 /* Use the default router if there is one */
1342                 neigh = neigh_clone(dn_db->router);
1343                 if (neigh) {
1344                         gateway = ((struct dn_neigh *)neigh)->addr;
1345                         goto make_route;
1346                 }
1347
1348                 /* Close eyes and pray */
1349                 gateway = cb->src;
1350                 flags |= RTCF_DIRECTSRC;
1351                 goto make_route;
1352         default:
1353                 goto e_inval;
1354         }
1355
1356 make_route:
1357         rt = dst_alloc(&dn_dst_ops);
1358         if (rt == NULL)
1359                 goto e_nobufs;
1360
1361         rt->rt_saddr      = fl.fld_src;
1362         rt->rt_daddr      = fl.fld_dst;
1363         rt->rt_gateway    = fl.fld_dst;
1364         if (gateway)
1365                 rt->rt_gateway = gateway;
1366         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1367
1368         rt->rt_dst_map    = fl.fld_dst;
1369         rt->rt_src_map    = fl.fld_src;
1370
1371         rt->fl.fld_src    = cb->src;
1372         rt->fl.fld_dst    = cb->dst;
1373         rt->fl.oif        = 0;
1374         rt->fl.iif        = in_dev->ifindex;
1375         rt->fl.mark       = fl.mark;
1376
1377         rt->dst.flags = DST_HOST;
1378         rt->dst.neighbour = neigh;
1379         rt->dst.dev = out_dev;
1380         rt->dst.lastuse = jiffies;
1381         rt->dst.output = dn_rt_bug;
1382         switch(res.type) {
1383                 case RTN_UNICAST:
1384                         rt->dst.input = dn_forward;
1385                         break;
1386                 case RTN_LOCAL:
1387                         rt->dst.output = dn_output;
1388                         rt->dst.input = dn_nsp_rx;
1389                         rt->dst.dev = in_dev;
1390                         flags |= RTCF_LOCAL;
1391                         break;
1392                 default:
1393                 case RTN_UNREACHABLE:
1394                 case RTN_BLACKHOLE:
1395                         rt->dst.input = dst_discard;
1396         }
1397         rt->rt_flags = flags;
1398         if (rt->dst.dev)
1399                 dev_hold(rt->dst.dev);
1400
1401         err = dn_rt_set_next_hop(rt, &res);
1402         if (err)
1403                 goto e_neighbour;
1404
1405         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1406         dn_insert_route(rt, hash, &rt);
1407         skb_dst_set(skb, &rt->dst);
1408
1409 done:
1410         if (neigh)
1411                 neigh_release(neigh);
1412         if (free_res)
1413                 dn_fib_res_put(&res);
1414         dev_put(in_dev);
1415         if (out_dev)
1416                 dev_put(out_dev);
1417 out:
1418         return err;
1419
1420 e_inval:
1421         err = -EINVAL;
1422         goto done;
1423
1424 e_nobufs:
1425         err = -ENOBUFS;
1426         goto done;
1427
1428 e_neighbour:
1429         dst_free(&rt->dst);
1430         goto done;
1431 }
1432
1433 static int dn_route_input(struct sk_buff *skb)
1434 {
1435         struct dn_route *rt;
1436         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1437         unsigned hash = dn_hash(cb->src, cb->dst);
1438
1439         if (skb_dst(skb))
1440                 return 0;
1441
1442         rcu_read_lock();
1443         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1444             rt = rcu_dereference(rt->dst.dn_next)) {
1445                 if ((rt->fl.fld_src == cb->src) &&
1446                     (rt->fl.fld_dst == cb->dst) &&
1447                     (rt->fl.oif == 0) &&
1448                     (rt->fl.mark == skb->mark) &&
1449                     (rt->fl.iif == cb->iif)) {
1450                         dst_use(&rt->dst, jiffies);
1451                         rcu_read_unlock();
1452                         skb_dst_set(skb, (struct dst_entry *)rt);
1453                         return 0;
1454                 }
1455         }
1456         rcu_read_unlock();
1457
1458         return dn_route_input_slow(skb);
1459 }
1460
1461 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1462                            int event, int nowait, unsigned int flags)
1463 {
1464         struct dn_route *rt = (struct dn_route *)skb_dst(skb);
1465         struct rtmsg *r;
1466         struct nlmsghdr *nlh;
1467         unsigned char *b = skb_tail_pointer(skb);
1468         long expires;
1469
1470         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1471         r = NLMSG_DATA(nlh);
1472         r->rtm_family = AF_DECnet;
1473         r->rtm_dst_len = 16;
1474         r->rtm_src_len = 0;
1475         r->rtm_tos = 0;
1476         r->rtm_table = RT_TABLE_MAIN;
1477         RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
1478         r->rtm_type = rt->rt_type;
1479         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1480         r->rtm_scope = RT_SCOPE_UNIVERSE;
1481         r->rtm_protocol = RTPROT_UNSPEC;
1482         if (rt->rt_flags & RTCF_NOTIFY)
1483                 r->rtm_flags |= RTM_F_NOTIFY;
1484         RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1485         if (rt->fl.fld_src) {
1486                 r->rtm_src_len = 16;
1487                 RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1488         }
1489         if (rt->dst.dev)
1490                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->dst.dev->ifindex);
1491         /*
1492          * Note to self - change this if input routes reverse direction when
1493          * they deal only with inputs and not with replies like they do
1494          * currently.
1495          */
1496         RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1497         if (rt->rt_daddr != rt->rt_gateway)
1498                 RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1499         if (rtnetlink_put_metrics(skb, rt->dst.metrics) < 0)
1500                 goto rtattr_failure;
1501         expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
1502         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, 0, 0, expires,
1503                                rt->dst.error) < 0)
1504                 goto rtattr_failure;
1505         if (rt->fl.iif)
1506                 RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1507
1508         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1509         return skb->len;
1510
1511 nlmsg_failure:
1512 rtattr_failure:
1513         nlmsg_trim(skb, b);
1514         return -1;
1515 }
1516
1517 /*
1518  * This is called by both endnodes and routers now.
1519  */
1520 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1521 {
1522         struct net *net = sock_net(in_skb->sk);
1523         struct rtattr **rta = arg;
1524         struct rtmsg *rtm = NLMSG_DATA(nlh);
1525         struct dn_route *rt = NULL;
1526         struct dn_skb_cb *cb;
1527         int err;
1528         struct sk_buff *skb;
1529         struct flowi fl;
1530
1531         if (!net_eq(net, &init_net))
1532                 return -EINVAL;
1533
1534         memset(&fl, 0, sizeof(fl));
1535         fl.proto = DNPROTO_NSP;
1536
1537         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1538         if (skb == NULL)
1539                 return -ENOBUFS;
1540         skb_reset_mac_header(skb);
1541         cb = DN_SKB_CB(skb);
1542
1543         if (rta[RTA_SRC-1])
1544                 memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1545         if (rta[RTA_DST-1])
1546                 memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1547         if (rta[RTA_IIF-1])
1548                 memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1549
1550         if (fl.iif) {
1551                 struct net_device *dev;
1552                 if ((dev = dev_get_by_index(&init_net, fl.iif)) == NULL) {
1553                         kfree_skb(skb);
1554                         return -ENODEV;
1555                 }
1556                 if (!dev->dn_ptr) {
1557                         dev_put(dev);
1558                         kfree_skb(skb);
1559                         return -ENODEV;
1560                 }
1561                 skb->protocol = htons(ETH_P_DNA_RT);
1562                 skb->dev = dev;
1563                 cb->src = fl.fld_src;
1564                 cb->dst = fl.fld_dst;
1565                 local_bh_disable();
1566                 err = dn_route_input(skb);
1567                 local_bh_enable();
1568                 memset(cb, 0, sizeof(struct dn_skb_cb));
1569                 rt = (struct dn_route *)skb_dst(skb);
1570                 if (!err && -rt->dst.error)
1571                         err = rt->dst.error;
1572         } else {
1573                 int oif = 0;
1574                 if (rta[RTA_OIF - 1])
1575                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1576                 fl.oif = oif;
1577                 err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1578         }
1579
1580         if (skb->dev)
1581                 dev_put(skb->dev);
1582         skb->dev = NULL;
1583         if (err)
1584                 goto out_free;
1585         skb_dst_set(skb, &rt->dst);
1586         if (rtm->rtm_flags & RTM_F_NOTIFY)
1587                 rt->rt_flags |= RTCF_NOTIFY;
1588
1589         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1590
1591         if (err == 0)
1592                 goto out_free;
1593         if (err < 0) {
1594                 err = -EMSGSIZE;
1595                 goto out_free;
1596         }
1597
1598         return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
1599
1600 out_free:
1601         kfree_skb(skb);
1602         return err;
1603 }
1604
1605 /*
1606  * For routers, this is called from dn_fib_dump, but for endnodes its
1607  * called directly from the rtnetlink dispatch table.
1608  */
1609 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1610 {
1611         struct net *net = sock_net(skb->sk);
1612         struct dn_route *rt;
1613         int h, s_h;
1614         int idx, s_idx;
1615
1616         if (!net_eq(net, &init_net))
1617                 return 0;
1618
1619         if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1620                 return -EINVAL;
1621         if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1622                 return 0;
1623
1624         s_h = cb->args[0];
1625         s_idx = idx = cb->args[1];
1626         for(h = 0; h <= dn_rt_hash_mask; h++) {
1627                 if (h < s_h)
1628                         continue;
1629                 if (h > s_h)
1630                         s_idx = 0;
1631                 rcu_read_lock_bh();
1632                 for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1633                         rt;
1634                         rt = rcu_dereference_bh(rt->dst.dn_next), idx++) {
1635                         if (idx < s_idx)
1636                                 continue;
1637                         skb_dst_set(skb, dst_clone(&rt->dst));
1638                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1639                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1640                                         1, NLM_F_MULTI) <= 0) {
1641                                 skb_dst_drop(skb);
1642                                 rcu_read_unlock_bh();
1643                                 goto done;
1644                         }
1645                         skb_dst_drop(skb);
1646                 }
1647                 rcu_read_unlock_bh();
1648         }
1649
1650 done:
1651         cb->args[0] = h;
1652         cb->args[1] = idx;
1653         return skb->len;
1654 }
1655
1656 #ifdef CONFIG_PROC_FS
1657 struct dn_rt_cache_iter_state {
1658         int bucket;
1659 };
1660
1661 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1662 {
1663         struct dn_route *rt = NULL;
1664         struct dn_rt_cache_iter_state *s = seq->private;
1665
1666         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1667                 rcu_read_lock_bh();
1668                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1669                 if (rt)
1670                         break;
1671                 rcu_read_unlock_bh();
1672         }
1673         return rt;
1674 }
1675
1676 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1677 {
1678         struct dn_rt_cache_iter_state *s = seq->private;
1679
1680         rt = rt->dst.dn_next;
1681         while(!rt) {
1682                 rcu_read_unlock_bh();
1683                 if (--s->bucket < 0)
1684                         break;
1685                 rcu_read_lock_bh();
1686                 rt = dn_rt_hash_table[s->bucket].chain;
1687         }
1688         return rcu_dereference_bh(rt);
1689 }
1690
1691 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1692 {
1693         struct dn_route *rt = dn_rt_cache_get_first(seq);
1694
1695         if (rt) {
1696                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1697                         --*pos;
1698         }
1699         return *pos ? NULL : rt;
1700 }
1701
1702 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1703 {
1704         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1705         ++*pos;
1706         return rt;
1707 }
1708
1709 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1710 {
1711         if (v)
1712                 rcu_read_unlock_bh();
1713 }
1714
1715 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1716 {
1717         struct dn_route *rt = v;
1718         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1719
1720         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1721                         rt->dst.dev ? rt->dst.dev->name : "*",
1722                         dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1723                         dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1724                         atomic_read(&rt->dst.__refcnt),
1725                         rt->dst.__use,
1726                         (int) dst_metric(&rt->dst, RTAX_RTT));
1727         return 0;
1728 }
1729
1730 static const struct seq_operations dn_rt_cache_seq_ops = {
1731         .start  = dn_rt_cache_seq_start,
1732         .next   = dn_rt_cache_seq_next,
1733         .stop   = dn_rt_cache_seq_stop,
1734         .show   = dn_rt_cache_seq_show,
1735 };
1736
1737 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1738 {
1739         return seq_open_private(file, &dn_rt_cache_seq_ops,
1740                         sizeof(struct dn_rt_cache_iter_state));
1741 }
1742
1743 static const struct file_operations dn_rt_cache_seq_fops = {
1744         .owner   = THIS_MODULE,
1745         .open    = dn_rt_cache_seq_open,
1746         .read    = seq_read,
1747         .llseek  = seq_lseek,
1748         .release = seq_release_private,
1749 };
1750
1751 #endif /* CONFIG_PROC_FS */
1752
1753 void __init dn_route_init(void)
1754 {
1755         int i, goal, order;
1756
1757         dn_dst_ops.kmem_cachep =
1758                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1759                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1760         dst_entries_init(&dn_dst_ops);
1761         setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1762         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1763         add_timer(&dn_route_timer);
1764
1765         goal = totalram_pages >> (26 - PAGE_SHIFT);
1766
1767         for(order = 0; (1UL << order) < goal; order++)
1768                 /* NOTHING */;
1769
1770         /*
1771          * Only want 1024 entries max, since the table is very, very unlikely
1772          * to be larger than that.
1773          */
1774         while(order && ((((1UL << order) * PAGE_SIZE) /
1775                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1776                 order--;
1777
1778         do {
1779                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1780                         sizeof(struct dn_rt_hash_bucket);
1781                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1782                         dn_rt_hash_mask--;
1783                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1784                         __get_free_pages(GFP_ATOMIC, order);
1785         } while (dn_rt_hash_table == NULL && --order > 0);
1786
1787         if (!dn_rt_hash_table)
1788                 panic("Failed to allocate DECnet route cache hash table\n");
1789
1790         printk(KERN_INFO
1791                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1792                 dn_rt_hash_mask,
1793                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1794
1795         dn_rt_hash_mask--;
1796         for(i = 0; i <= dn_rt_hash_mask; i++) {
1797                 spin_lock_init(&dn_rt_hash_table[i].lock);
1798                 dn_rt_hash_table[i].chain = NULL;
1799         }
1800
1801         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1802
1803         proc_net_fops_create(&init_net, "decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1804
1805 #ifdef CONFIG_DECNET_ROUTER
1806         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute, dn_fib_dump);
1807 #else
1808         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1809                       dn_cache_dump);
1810 #endif
1811 }
1812
1813 void __exit dn_route_cleanup(void)
1814 {
1815         del_timer(&dn_route_timer);
1816         dn_run_flush(0);
1817
1818         proc_net_remove(&init_net, "decnet_cache");
1819         dst_entries_destroy(&dn_dst_ops);
1820 }
1821