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