net/decnet/dn_route.c

   1 /*
   2  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   3  *              operating system.  DECnet is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              DECnet Routing Functions (Endnode and Router)
   7  *
   8  * Authors:     Steve Whitehouse <SteveW@ACM.org>
   9  *              Eduardo Marcelo Serrat <emserrat@geocities.com>
  10  *
  11  * Changes:
  12  *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
  13  *                                 "return-to-sender" bits on outgoing
  14  *                                 packets.
  15  *              Steve Whitehouse : Timeouts for cached routes.
  16  *              Steve Whitehouse : Use dst cache for input routes too.
  17  *              Steve Whitehouse : Fixed error values in dn_send_skb.
  18  *              Steve Whitehouse : Rework routing functions to better fit
  19  *                                 DECnet routing design
  20  *              Alexey Kuznetsov : New SMP locking
  21  *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
  22  *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
  23  *                                 Fixed possible skb leak in rtnetlink funcs.
  24  *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
  25  *                                 Alexey Kuznetsov's finer grained locking
  26  *                                 from ipv4/route.c.
  27  *              Steve Whitehouse : Routing is now starting to look like a
  28  *                                 sensible set of code now, mainly due to
  29  *                                 my copying the IPv4 routing code. The
  30  *                                 hooks here are modified and will continue
  31  *                                 to evolve for a while.
  32  *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
  33  *                                 stuff. Look out raw sockets your days
  34  *                                 are numbered!
  35  *              Steve Whitehouse : Added return-to-sender functions. Added
  36  *                                 backlog congestion level return codes.
  37  *              Steve Whitehouse : Fixed bug where routes were set up with
  38  *                                 no ref count on net devices.
  39  *              Steve Whitehouse : RCU for the route cache
  40  *              Steve Whitehouse : Preparations for the flow cache
  41  *              Steve Whitehouse : Prepare for nonlinear skbs
  42  */
  43
  44 /******************************************************************************
  45     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
  46
  47     This program is free software; you can redistribute it and/or modify
  48     it under the terms of the GNU General Public License as published by
  49     the Free Software Foundation; either version 2 of the License, or
  50     any later version.
  51
  52     This program is distributed in the hope that it will be useful,
  53     but WITHOUT ANY WARRANTY; without even the implied warranty of
  54     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  55     GNU General Public License for more details.
  56 *******************************************************************************/
  57
  58 #include <linux/errno.h>
  59 #include <linux/types.h>
  60 #include <linux/socket.h>
  61 #include <linux/in.h>
  62 #include <linux/kernel.h>
  63 #include <linux/sockios.h>
  64 #include <linux/net.h>
  65 #include <linux/netdevice.h>
  66 #include <linux/inet.h>
  67 #include <linux/route.h>
  68 #include <linux/in_route.h>
  69 #include <net/sock.h>
  70 #include <linux/mm.h>
  71 #include <linux/proc_fs.h>
  72 #include <linux/seq_file.h>
  73 #include <linux/init.h>
  74 #include <linux/rtnetlink.h>
  75 #include <linux/string.h>
  76 #include <linux/netfilter_decnet.h>
  77 #include <linux/rcupdate.h>
  78 #include <linux/times.h>
  79 #include <asm/errno.h>
  80 #include <net/net_namespace.h>
  81 #include <net/netlink.h>
  82 #include <net/neighbour.h>
  83 #include <net/dst.h>
  84 #include <net/flow.h>
  85 #include <net/fib_rules.h>
  86 #include <net/dn.h>
  87 #include <net/dn_dev.h>
  88 #include <net/dn_nsp.h>
  89 #include <net/dn_route.h>
  90 #include <net/dn_neigh.h>
  91 #include <net/dn_fib.h>
  92
  93 struct dn_rt_hash_bucket
  94 {
  95         struct dn_route *chain;
  96         spinlock_t lock;
  97 };
  98
  99 extern struct neigh_table dn_neigh_table;
 100
 101
 102 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 103
 104 static const int dn_rt_min_delay = 2 * HZ;
 105 static const int dn_rt_max_delay = 10 * HZ;
 106 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 107
 108 static unsigned long dn_rt_deadline;
 109
 110 static int dn_dst_gc(struct dst_ops *ops);
 111 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 112 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 113 static void dn_dst_link_failure(struct sk_buff *);
 114 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
 115 static int dn_route_input(struct sk_buff *);
 116 static void dn_run_flush(unsigned long dummy);
 117
 118 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 119 static unsigned dn_rt_hash_mask;
 120
 121 static struct timer_list dn_route_timer;
 122 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 123 int decnet_dst_gc_interval = 2;
 124
 125 static struct dst_ops dn_dst_ops = {
 126         .family =               PF_DECnet,
 127         .protocol =             __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(struct dst_ops *ops)
 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_metric(dst, RTAX_MTU) > 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_metric(dst, RTAX_ADVMSS) > 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 (!net_eq(dev_net(dev), &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  * Used to catch bugs. This should never normally get
 769  * called.
 770  */
 771 static int dn_rt_bug(struct sk_buff *skb)
 772 {
 773         if (net_ratelimit()) {
 774                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 775
 776                 printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
 777                                 dn_ntohs(cb->src), dn_ntohs(cb->dst));
 778         }
 779
 780         kfree_skb(skb);
 781
 782         return NET_RX_BAD;
 783 }
 784
 785 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 786 {
 787         struct dn_fib_info *fi = res->fi;
 788         struct net_device *dev = rt->u.dst.dev;
 789         struct neighbour *n;
 790         unsigned mss;
 791
 792         if (fi) {
 793                 if (DN_FIB_RES_GW(*res) &&
 794                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 795                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 796                 memcpy(rt->u.dst.metrics, fi->fib_metrics,
 797                        sizeof(rt->u.dst.metrics));
 798         }
 799         rt->rt_type = res->type;
 800
 801         if (dev != NULL && rt->u.dst.neighbour == NULL) {
 802                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 803                 if (IS_ERR(n))
 804                         return PTR_ERR(n);
 805                 rt->u.dst.neighbour = n;
 806         }
 807
 808         if (dst_metric(&rt->u.dst, RTAX_MTU) == 0 ||
 809             dst_metric(&rt->u.dst, RTAX_MTU) > rt->u.dst.dev->mtu)
 810                 rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
 811         mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->u.dst));
 812         if (dst_metric(&rt->u.dst, RTAX_ADVMSS) == 0 ||
 813             dst_metric(&rt->u.dst, RTAX_ADVMSS) > mss)
 814                 rt->u.dst.metrics[RTAX_ADVMSS-1] = mss;
 815         return 0;
 816 }
 817
 818 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 819 {
 820         __u16 tmp = dn_ntohs(addr1) ^ dn_ntohs(addr2);
 821         int match = 16;
 822         while(tmp) {
 823                 tmp >>= 1;
 824                 match--;
 825         }
 826         return match;
 827 }
 828
 829 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 830 {
 831         __le16 saddr = 0;
 832         struct dn_dev *dn_db = dev->dn_ptr;
 833         struct dn_ifaddr *ifa;
 834         int best_match = 0;
 835         int ret;
 836
 837         read_lock(&dev_base_lock);
 838         for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
 839                 if (ifa->ifa_scope > scope)
 840                         continue;
 841                 if (!daddr) {
 842                         saddr = ifa->ifa_local;
 843                         break;
 844                 }
 845                 ret = dn_match_addr(daddr, ifa->ifa_local);
 846                 if (ret > best_match)
 847                         saddr = ifa->ifa_local;
 848                 if (best_match == 0)
 849                         saddr = ifa->ifa_local;
 850         }
 851         read_unlock(&dev_base_lock);
 852
 853         return saddr;
 854 }
 855
 856 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 857 {
 858         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 859 }
 860
 861 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 862 {
 863         __le16 mask = dnet_make_mask(res->prefixlen);
 864         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 865 }
 866
 867 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
 868 {
 869         struct flowi fl = { .nl_u = { .dn_u =
 870                                       { .daddr = oldflp->fld_dst,
 871                                         .saddr = oldflp->fld_src,
 872                                         .scope = RT_SCOPE_UNIVERSE,
 873                                      } },
 874                             .mark = oldflp->mark,
 875                             .iif = init_net.loopback_dev->ifindex,
 876                             .oif = oldflp->oif };
 877         struct dn_route *rt = NULL;
 878         struct net_device *dev_out = NULL, *dev;
 879         struct neighbour *neigh = NULL;
 880         unsigned hash;
 881         unsigned flags = 0;
 882         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 883         int err;
 884         int free_res = 0;
 885         __le16 gateway = 0;
 886
 887         if (decnet_debug_level & 16)
 888                 printk(KERN_DEBUG
 889                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 890                        " iif=%d oif=%d\n", dn_ntohs(oldflp->fld_dst),
 891                        dn_ntohs(oldflp->fld_src),
 892                        oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);
 893
 894         /* If we have an output interface, verify its a DECnet device */
 895         if (oldflp->oif) {
 896                 dev_out = dev_get_by_index(&init_net, oldflp->oif);
 897                 err = -ENODEV;
 898                 if (dev_out && dev_out->dn_ptr == NULL) {
 899                         dev_put(dev_out);
 900                         dev_out = NULL;
 901                 }
 902                 if (dev_out == NULL)
 903                         goto out;
 904         }
 905
 906         /* If we have a source address, verify that its a local address */
 907         if (oldflp->fld_src) {
 908                 err = -EADDRNOTAVAIL;
 909
 910                 if (dev_out) {
 911                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
 912                                 goto source_ok;
 913                         dev_put(dev_out);
 914                         goto out;
 915                 }
 916                 read_lock(&dev_base_lock);
 917                 for_each_netdev(&init_net, dev) {
 918                         if (!dev->dn_ptr)
 919                                 continue;
 920                         if (!dn_dev_islocal(dev, oldflp->fld_src))
 921                                 continue;
 922                         if ((dev->flags & IFF_LOOPBACK) &&
 923                             oldflp->fld_dst &&
 924                             !dn_dev_islocal(dev, oldflp->fld_dst))
 925                                 continue;
 926
 927                         dev_out = dev;
 928                         break;
 929                 }
 930                 read_unlock(&dev_base_lock);
 931                 if (dev_out == NULL)
 932                         goto out;
 933                 dev_hold(dev_out);
 934 source_ok:
 935                 ;
 936         }
 937
 938         /* No destination? Assume its local */
 939         if (!fl.fld_dst) {
 940                 fl.fld_dst = fl.fld_src;
 941
 942                 err = -EADDRNOTAVAIL;
 943                 if (dev_out)
 944                         dev_put(dev_out);
 945                 dev_out = init_net.loopback_dev;
 946                 dev_hold(dev_out);
 947                 if (!fl.fld_dst) {
 948                         fl.fld_dst =
 949                         fl.fld_src = dnet_select_source(dev_out, 0,
 950                                                        RT_SCOPE_HOST);
 951                         if (!fl.fld_dst)
 952                                 goto out;
 953                 }
 954                 fl.oif = init_net.loopback_dev->ifindex;
 955                 res.type = RTN_LOCAL;
 956                 goto make_route;
 957         }
 958
 959         if (decnet_debug_level & 16)
 960                 printk(KERN_DEBUG
 961                        "dn_route_output_slow: initial checks complete."
 962                        " dst=%o4x src=%04x oif=%d try_hard=%d\n",
 963                        dn_ntohs(fl.fld_dst), dn_ntohs(fl.fld_src),
 964                        fl.oif, try_hard);
 965
 966         /*
 967          * N.B. If the kernel is compiled without router support then
 968          * dn_fib_lookup() will evaluate to non-zero so this if () block
 969          * will always be executed.
 970          */
 971         err = -ESRCH;
 972         if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
 973                 struct dn_dev *dn_db;
 974                 if (err != -ESRCH)
 975                         goto out;
 976                 /*
 977                  * Here the fallback is basically the standard algorithm for
 978                  * routing in endnodes which is described in the DECnet routing
 979                  * docs
 980                  *
 981                  * If we are not trying hard, look in neighbour cache.
 982                  * The result is tested to ensure that if a specific output
 983                  * device/source address was requested, then we honour that
 984                  * here
 985                  */
 986                 if (!try_hard) {
 987                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fl.fld_dst);
 988                         if (neigh) {
 989                                 if ((oldflp->oif &&
 990                                     (neigh->dev->ifindex != oldflp->oif)) ||
 991                                     (oldflp->fld_src &&
 992                                     (!dn_dev_islocal(neigh->dev,
 993                                                       oldflp->fld_src)))) {
 994                                         neigh_release(neigh);
 995                                         neigh = NULL;
 996                                 } else {
 997                                         if (dev_out)
 998                                                 dev_put(dev_out);
 999                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
1000                                                 dev_out = init_net.loopback_dev;
1001                                                 res.type = RTN_LOCAL;
1002                                         } else {
1003                                                 dev_out = neigh->dev;
1004                                         }
1005                                         dev_hold(dev_out);
1006                                         goto select_source;
1007                                 }
1008                         }
1009                 }
1010
1011                 /* Not there? Perhaps its a local address */
1012                 if (dev_out == NULL)
1013                         dev_out = dn_dev_get_default();
1014                 err = -ENODEV;
1015                 if (dev_out == NULL)
1016                         goto out;
1017                 dn_db = dev_out->dn_ptr;
1018                 /* Possible improvement - check all devices for local addr */
1019                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1020                         dev_put(dev_out);
1021                         dev_out = init_net.loopback_dev;
1022                         dev_hold(dev_out);
1023                         res.type = RTN_LOCAL;
1024                         goto select_source;
1025                 }
1026                 /* Not local either.... try sending it to the default router */
1027                 neigh = neigh_clone(dn_db->router);
1028                 BUG_ON(neigh && neigh->dev != dev_out);
1029
1030                 /* Ok then, we assume its directly connected and move on */
1031 select_source:
1032                 if (neigh)
1033                         gateway = ((struct dn_neigh *)neigh)->addr;
1034                 if (gateway == 0)
1035                         gateway = fl.fld_dst;
1036                 if (fl.fld_src == 0) {
1037                         fl.fld_src = dnet_select_source(dev_out, gateway,
1038                                                          res.type == RTN_LOCAL ?
1039                                                          RT_SCOPE_HOST :
1040                                                          RT_SCOPE_LINK);
1041                         if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1042                                 goto e_addr;
1043                 }
1044                 fl.oif = dev_out->ifindex;
1045                 goto make_route;
1046         }
1047         free_res = 1;
1048
1049         if (res.type == RTN_NAT)
1050                 goto e_inval;
1051
1052         if (res.type == RTN_LOCAL) {
1053                 if (!fl.fld_src)
1054                         fl.fld_src = fl.fld_dst;
1055                 if (dev_out)
1056                         dev_put(dev_out);
1057                 dev_out = init_net.loopback_dev;
1058                 dev_hold(dev_out);
1059                 fl.oif = dev_out->ifindex;
1060                 if (res.fi)
1061                         dn_fib_info_put(res.fi);
1062                 res.fi = NULL;
1063                 goto make_route;
1064         }
1065
1066         if (res.fi->fib_nhs > 1 && fl.oif == 0)
1067                 dn_fib_select_multipath(&fl, &res);
1068
1069         /*
1070          * We could add some logic to deal with default routes here and
1071          * get rid of some of the special casing above.
1072          */
1073
1074         if (!fl.fld_src)
1075                 fl.fld_src = DN_FIB_RES_PREFSRC(res);
1076
1077         if (dev_out)
1078                 dev_put(dev_out);
1079         dev_out = DN_FIB_RES_DEV(res);
1080         dev_hold(dev_out);
1081         fl.oif = dev_out->ifindex;
1082         gateway = DN_FIB_RES_GW(res);
1083
1084 make_route:
1085         if (dev_out->flags & IFF_LOOPBACK)
1086                 flags |= RTCF_LOCAL;
1087
1088         rt = dst_alloc(&dn_dst_ops);
1089         if (rt == NULL)
1090                 goto e_nobufs;
1091
1092         atomic_set(&rt->u.dst.__refcnt, 1);
1093         rt->u.dst.flags   = DST_HOST;
1094
1095         rt->fl.fld_src    = oldflp->fld_src;
1096         rt->fl.fld_dst    = oldflp->fld_dst;
1097         rt->fl.oif        = oldflp->oif;
1098         rt->fl.iif        = 0;
1099         rt->fl.mark       = oldflp->mark;
1100
1101         rt->rt_saddr      = fl.fld_src;
1102         rt->rt_daddr      = fl.fld_dst;
1103         rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1104         rt->rt_local_src  = fl.fld_src;
1105
1106         rt->rt_dst_map    = fl.fld_dst;
1107         rt->rt_src_map    = fl.fld_src;
1108
1109         rt->u.dst.dev = dev_out;
1110         dev_hold(dev_out);
1111         rt->u.dst.neighbour = neigh;
1112         neigh = NULL;
1113
1114         rt->u.dst.lastuse = jiffies;
1115         rt->u.dst.output  = dn_output;
1116         rt->u.dst.input   = dn_rt_bug;
1117         rt->rt_flags      = flags;
1118         if (flags & RTCF_LOCAL)
1119                 rt->u.dst.input = dn_nsp_rx;
1120
1121         err = dn_rt_set_next_hop(rt, &res);
1122         if (err)
1123                 goto e_neighbour;
1124
1125         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1126         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1127
1128 done:
1129         if (neigh)
1130                 neigh_release(neigh);
1131         if (free_res)
1132                 dn_fib_res_put(&res);
1133         if (dev_out)
1134                 dev_put(dev_out);
1135 out:
1136         return err;
1137
1138 e_addr:
1139         err = -EADDRNOTAVAIL;
1140         goto done;
1141 e_inval:
1142         err = -EINVAL;
1143         goto done;
1144 e_nobufs:
1145         err = -ENOBUFS;
1146         goto done;
1147 e_neighbour:
1148         dst_free(&rt->u.dst);
1149         goto e_nobufs;
1150 }
1151
1152
1153 /*
1154  * N.B. The flags may be moved into the flowi at some future stage.
1155  */
1156 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1157 {
1158         unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1159         struct dn_route *rt = NULL;
1160
1161         if (!(flags & MSG_TRYHARD)) {
1162                 rcu_read_lock_bh();
1163                 for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt;
1164                         rt = rcu_dereference(rt->u.dst.dn_next)) {
1165                         if ((flp->fld_dst == rt->fl.fld_dst) &&
1166                             (flp->fld_src == rt->fl.fld_src) &&
1167                             (flp->mark == rt->fl.mark) &&
1168                             (rt->fl.iif == 0) &&
1169                             (rt->fl.oif == flp->oif)) {
1170                                 dst_use(&rt->u.dst, jiffies);
1171                                 rcu_read_unlock_bh();
1172                                 *pprt = &rt->u.dst;
1173                                 return 0;
1174                         }
1175                 }
1176                 rcu_read_unlock_bh();
1177         }
1178
1179         return dn_route_output_slow(pprt, flp, flags);
1180 }
1181
1182 static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
1183 {
1184         int err;
1185
1186         err = __dn_route_output_key(pprt, flp, flags);
1187         if (err == 0 && flp->proto) {
1188                 err = xfrm_lookup(pprt, flp, NULL, 0);
1189         }
1190         return err;
1191 }
1192
1193 int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
1194 {
1195         int err;
1196
1197         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1198         if (err == 0 && fl->proto) {
1199                 err = xfrm_lookup(pprt, fl, sk, (flags & MSG_DONTWAIT) ?
1200                                                 0 : XFRM_LOOKUP_WAIT);
1201         }
1202         return err;
1203 }
1204
1205 static int dn_route_input_slow(struct sk_buff *skb)
1206 {
1207         struct dn_route *rt = NULL;
1208         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1209         struct net_device *in_dev = skb->dev;
1210         struct net_device *out_dev = NULL;
1211         struct dn_dev *dn_db;
1212         struct neighbour *neigh = NULL;
1213         unsigned hash;
1214         int flags = 0;
1215         __le16 gateway = 0;
1216         __le16 local_src = 0;
1217         struct flowi fl = { .nl_u = { .dn_u =
1218                                      { .daddr = cb->dst,
1219                                        .saddr = cb->src,
1220                                        .scope = RT_SCOPE_UNIVERSE,
1221                                     } },
1222                             .mark = skb->mark,
1223                             .iif = skb->dev->ifindex };
1224         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1225         int err = -EINVAL;
1226         int free_res = 0;
1227
1228         dev_hold(in_dev);
1229
1230         if ((dn_db = in_dev->dn_ptr) == NULL)
1231                 goto out;
1232
1233         /* Zero source addresses are not allowed */
1234         if (fl.fld_src == 0)
1235                 goto out;
1236
1237         /*
1238          * In this case we've just received a packet from a source
1239          * outside ourselves pretending to come from us. We don't
1240          * allow it any further to prevent routing loops, spoofing and
1241          * other nasties. Loopback packets already have the dst attached
1242          * so this only affects packets which have originated elsewhere.
1243          */
1244         err  = -ENOTUNIQ;
1245         if (dn_dev_islocal(in_dev, cb->src))
1246                 goto out;
1247
1248         err = dn_fib_lookup(&fl, &res);
1249         if (err) {
1250                 if (err != -ESRCH)
1251                         goto out;
1252                 /*
1253                  * Is the destination us ?
1254                  */
1255                 if (!dn_dev_islocal(in_dev, cb->dst))
1256                         goto e_inval;
1257
1258                 res.type = RTN_LOCAL;
1259         } else {
1260                 __le16 src_map = fl.fld_src;
1261                 free_res = 1;
1262
1263                 out_dev = DN_FIB_RES_DEV(res);
1264                 if (out_dev == NULL) {
1265                         if (net_ratelimit())
1266                                 printk(KERN_CRIT "Bug in dn_route_input_slow() "
1267                                                  "No output device\n");
1268                         goto e_inval;
1269                 }
1270                 dev_hold(out_dev);
1271
1272                 if (res.r)
1273                         src_map = fl.fld_src; /* no NAT support for now */
1274
1275                 gateway = DN_FIB_RES_GW(res);
1276                 if (res.type == RTN_NAT) {
1277                         fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1278                         dn_fib_res_put(&res);
1279                         free_res = 0;
1280                         if (dn_fib_lookup(&fl, &res))
1281                                 goto e_inval;
1282                         free_res = 1;
1283                         if (res.type != RTN_UNICAST)
1284                                 goto e_inval;
1285                         flags |= RTCF_DNAT;
1286                         gateway = fl.fld_dst;
1287                 }
1288                 fl.fld_src = src_map;
1289         }
1290
1291         switch(res.type) {
1292         case RTN_UNICAST:
1293                 /*
1294                  * Forwarding check here, we only check for forwarding
1295                  * being turned off, if you want to only forward intra
1296                  * area, its up to you to set the routing tables up
1297                  * correctly.
1298                  */
1299                 if (dn_db->parms.forwarding == 0)
1300                         goto e_inval;
1301
1302                 if (res.fi->fib_nhs > 1 && fl.oif == 0)
1303                         dn_fib_select_multipath(&fl, &res);
1304
1305                 /*
1306                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1307                  * flag as a hint to set the intra-ethernet bit when
1308                  * forwarding. If we've got NAT in operation, we don't do
1309                  * this optimisation.
1310                  */
1311                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1312                         flags |= RTCF_DOREDIRECT;
1313
1314                 local_src = DN_FIB_RES_PREFSRC(res);
1315
1316         case RTN_BLACKHOLE:
1317         case RTN_UNREACHABLE:
1318                 break;
1319         case RTN_LOCAL:
1320                 flags |= RTCF_LOCAL;
1321                 fl.fld_src = cb->dst;
1322                 fl.fld_dst = cb->src;
1323
1324                 /* Routing tables gave us a gateway */
1325                 if (gateway)
1326                         goto make_route;
1327
1328                 /* Packet was intra-ethernet, so we know its on-link */
1329                 if (cb->rt_flags & DN_RT_F_IE) {
1330                         gateway = cb->src;
1331                         flags |= RTCF_DIRECTSRC;
1332                         goto make_route;
1333                 }
1334
1335                 /* Use the default router if there is one */
1336                 neigh = neigh_clone(dn_db->router);
1337                 if (neigh) {
1338                         gateway = ((struct dn_neigh *)neigh)->addr;
1339                         goto make_route;
1340                 }
1341
1342                 /* Close eyes and pray */
1343                 gateway = cb->src;
1344                 flags |= RTCF_DIRECTSRC;
1345                 goto make_route;
1346         default:
1347                 goto e_inval;
1348         }
1349
1350 make_route:
1351         rt = dst_alloc(&dn_dst_ops);
1352         if (rt == NULL)
1353                 goto e_nobufs;
1354
1355         rt->rt_saddr      = fl.fld_src;
1356         rt->rt_daddr      = fl.fld_dst;
1357         rt->rt_gateway    = fl.fld_dst;
1358         if (gateway)
1359                 rt->rt_gateway = gateway;
1360         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1361
1362         rt->rt_dst_map    = fl.fld_dst;
1363         rt->rt_src_map    = fl.fld_src;
1364
1365         rt->fl.fld_src    = cb->src;
1366         rt->fl.fld_dst    = cb->dst;
1367         rt->fl.oif        = 0;
1368         rt->fl.iif        = in_dev->ifindex;
1369         rt->fl.mark       = fl.mark;
1370
1371         rt->u.dst.flags = DST_HOST;
1372         rt->u.dst.neighbour = neigh;
1373         rt->u.dst.dev = out_dev;
1374         rt->u.dst.lastuse = jiffies;
1375         rt->u.dst.output = dn_rt_bug;
1376         switch(res.type) {
1377                 case RTN_UNICAST:
1378                         rt->u.dst.input = dn_forward;
1379                         break;
1380                 case RTN_LOCAL:
1381                         rt->u.dst.output = dn_output;
1382                         rt->u.dst.input = dn_nsp_rx;
1383                         rt->u.dst.dev = in_dev;
1384                         flags |= RTCF_LOCAL;
1385                         break;
1386                 default:
1387                 case RTN_UNREACHABLE:
1388                 case RTN_BLACKHOLE:
1389                         rt->u.dst.input = dst_discard;
1390         }
1391         rt->rt_flags = flags;
1392         if (rt->u.dst.dev)
1393                 dev_hold(rt->u.dst.dev);
1394
1395         err = dn_rt_set_next_hop(rt, &res);
1396         if (err)
1397                 goto e_neighbour;
1398
1399         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1400         dn_insert_route(rt, hash, (struct dn_route **)&skb->dst);
1401
1402 done:
1403         if (neigh)
1404                 neigh_release(neigh);
1405         if (free_res)
1406                 dn_fib_res_put(&res);
1407         dev_put(in_dev);
1408         if (out_dev)
1409                 dev_put(out_dev);
1410 out:
1411         return err;
1412
1413 e_inval:
1414         err = -EINVAL;
1415         goto done;
1416
1417 e_nobufs:
1418         err = -ENOBUFS;
1419         goto done;
1420
1421 e_neighbour:
1422         dst_free(&rt->u.dst);
1423         goto done;
1424 }
1425
1426 int dn_route_input(struct sk_buff *skb)
1427 {
1428         struct dn_route *rt;
1429         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1430         unsigned hash = dn_hash(cb->src, cb->dst);
1431
1432         if (skb->dst)
1433                 return 0;
1434
1435         rcu_read_lock();
1436         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1437             rt = rcu_dereference(rt->u.dst.dn_next)) {
1438                 if ((rt->fl.fld_src == cb->src) &&
1439                     (rt->fl.fld_dst == cb->dst) &&
1440                     (rt->fl.oif == 0) &&
1441                     (rt->fl.mark == skb->mark) &&
1442                     (rt->fl.iif == cb->iif)) {
1443                         dst_use(&rt->u.dst, jiffies);
1444                         rcu_read_unlock();
1445                         skb->dst = (struct dst_entry *)rt;
1446                         return 0;
1447                 }
1448         }
1449         rcu_read_unlock();
1450
1451         return dn_route_input_slow(skb);
1452 }
1453
1454 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1455                            int event, int nowait, unsigned int flags)
1456 {
1457         struct dn_route *rt = (struct dn_route *)skb->dst;
1458         struct rtmsg *r;
1459         struct nlmsghdr *nlh;
1460         unsigned char *b = skb_tail_pointer(skb);
1461         long expires;
1462
1463         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1464         r = NLMSG_DATA(nlh);
1465         r->rtm_family = AF_DECnet;
1466         r->rtm_dst_len = 16;
1467         r->rtm_src_len = 0;
1468         r->rtm_tos = 0;
1469         r->rtm_table = RT_TABLE_MAIN;
1470         RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
1471         r->rtm_type = rt->rt_type;
1472         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1473         r->rtm_scope = RT_SCOPE_UNIVERSE;
1474         r->rtm_protocol = RTPROT_UNSPEC;
1475         if (rt->rt_flags & RTCF_NOTIFY)
1476                 r->rtm_flags |= RTM_F_NOTIFY;
1477         RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1478         if (rt->fl.fld_src) {
1479                 r->rtm_src_len = 16;
1480                 RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1481         }
1482         if (rt->u.dst.dev)
1483                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
1484         /*
1485          * Note to self - change this if input routes reverse direction when
1486          * they deal only with inputs and not with replies like they do
1487          * currently.
1488          */
1489         RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1490         if (rt->rt_daddr != rt->rt_gateway)
1491                 RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1492         if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
1493                 goto rtattr_failure;
1494         expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
1495         if (rtnl_put_cacheinfo(skb, &rt->u.dst, 0, 0, 0, expires,
1496                                rt->u.dst.error) < 0)
1497                 goto rtattr_failure;
1498         if (rt->fl.iif)
1499                 RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1500
1501         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1502         return skb->len;
1503
1504 nlmsg_failure:
1505 rtattr_failure:
1506         nlmsg_trim(skb, b);
1507         return -1;
1508 }
1509
1510 /*
1511  * This is called by both endnodes and routers now.
1512  */
1513 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1514 {
1515         struct net *net = sock_net(in_skb->sk);
1516         struct rtattr **rta = arg;
1517         struct rtmsg *rtm = NLMSG_DATA(nlh);
1518         struct dn_route *rt = NULL;
1519         struct dn_skb_cb *cb;
1520         int err;
1521         struct sk_buff *skb;
1522         struct flowi fl;
1523
1524         if (net != &init_net)
1525                 return -EINVAL;
1526
1527         memset(&fl, 0, sizeof(fl));
1528         fl.proto = DNPROTO_NSP;
1529
1530         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1531         if (skb == NULL)
1532                 return -ENOBUFS;
1533         skb_reset_mac_header(skb);
1534         cb = DN_SKB_CB(skb);
1535
1536         if (rta[RTA_SRC-1])
1537                 memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1538         if (rta[RTA_DST-1])
1539                 memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1540         if (rta[RTA_IIF-1])
1541                 memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1542
1543         if (fl.iif) {
1544                 struct net_device *dev;
1545                 if ((dev = dev_get_by_index(&init_net, fl.iif)) == NULL) {
1546                         kfree_skb(skb);
1547                         return -ENODEV;
1548                 }
1549                 if (!dev->dn_ptr) {
1550                         dev_put(dev);
1551                         kfree_skb(skb);
1552                         return -ENODEV;
1553                 }
1554                 skb->protocol = htons(ETH_P_DNA_RT);
1555                 skb->dev = dev;
1556                 cb->src = fl.fld_src;
1557                 cb->dst = fl.fld_dst;
1558                 local_bh_disable();
1559                 err = dn_route_input(skb);
1560                 local_bh_enable();
1561                 memset(cb, 0, sizeof(struct dn_skb_cb));
1562                 rt = (struct dn_route *)skb->dst;
1563                 if (!err && -rt->u.dst.error)
1564                         err = rt->u.dst.error;
1565         } else {
1566                 int oif = 0;
1567                 if (rta[RTA_OIF - 1])
1568                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1569                 fl.oif = oif;
1570                 err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1571         }
1572
1573         if (skb->dev)
1574                 dev_put(skb->dev);
1575         skb->dev = NULL;
1576         if (err)
1577                 goto out_free;
1578         skb->dst = &rt->u.dst;
1579         if (rtm->rtm_flags & RTM_F_NOTIFY)
1580                 rt->rt_flags |= RTCF_NOTIFY;
1581
1582         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1583
1584         if (err == 0)
1585                 goto out_free;
1586         if (err < 0) {
1587                 err = -EMSGSIZE;
1588                 goto out_free;
1589         }
1590
1591         return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
1592
1593 out_free:
1594         kfree_skb(skb);
1595         return err;
1596 }
1597
1598 /*
1599  * For routers, this is called from dn_fib_dump, but for endnodes its
1600  * called directly from the rtnetlink dispatch table.
1601  */
1602 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1603 {
1604         struct net *net = sock_net(skb->sk);
1605         struct dn_route *rt;
1606         int h, s_h;
1607         int idx, s_idx;
1608
1609         if (net != &init_net)
1610                 return 0;
1611
1612         if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1613                 return -EINVAL;
1614         if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1615                 return 0;
1616
1617         s_h = cb->args[0];
1618         s_idx = idx = cb->args[1];
1619         for(h = 0; h <= dn_rt_hash_mask; h++) {
1620                 if (h < s_h)
1621                         continue;
1622                 if (h > s_h)
1623                         s_idx = 0;
1624                 rcu_read_lock_bh();
1625                 for(rt = rcu_dereference(dn_rt_hash_table[h].chain), idx = 0;
1626                         rt;
1627                         rt = rcu_dereference(rt->u.dst.dn_next), idx++) {
1628                         if (idx < s_idx)
1629                                 continue;
1630                         skb->dst = dst_clone(&rt->u.dst);
1631                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1632                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1633                                         1, NLM_F_MULTI) <= 0) {
1634                                 dst_release(xchg(&skb->dst, NULL));
1635                                 rcu_read_unlock_bh();
1636                                 goto done;
1637                         }
1638                         dst_release(xchg(&skb->dst, NULL));
1639                 }
1640                 rcu_read_unlock_bh();
1641         }
1642
1643 done:
1644         cb->args[0] = h;
1645         cb->args[1] = idx;
1646         return skb->len;
1647 }
1648
1649 #ifdef CONFIG_PROC_FS
1650 struct dn_rt_cache_iter_state {
1651         int bucket;
1652 };
1653
1654 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1655 {
1656         struct dn_route *rt = NULL;
1657         struct dn_rt_cache_iter_state *s = seq->private;
1658
1659         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1660                 rcu_read_lock_bh();
1661                 rt = dn_rt_hash_table[s->bucket].chain;
1662                 if (rt)
1663                         break;
1664                 rcu_read_unlock_bh();
1665         }
1666         return rcu_dereference(rt);
1667 }
1668
1669 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1670 {
1671         struct dn_rt_cache_iter_state *s = seq->private;
1672
1673         rt = rt->u.dst.dn_next;
1674         while(!rt) {
1675                 rcu_read_unlock_bh();
1676                 if (--s->bucket < 0)
1677                         break;
1678                 rcu_read_lock_bh();
1679                 rt = dn_rt_hash_table[s->bucket].chain;
1680         }
1681         return rcu_dereference(rt);
1682 }
1683
1684 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1685 {
1686         struct dn_route *rt = dn_rt_cache_get_first(seq);
1687
1688         if (rt) {
1689                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1690                         --*pos;
1691         }
1692         return *pos ? NULL : rt;
1693 }
1694
1695 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1696 {
1697         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1698         ++*pos;
1699         return rt;
1700 }
1701
1702 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1703 {
1704         if (v)
1705                 rcu_read_unlock_bh();
1706 }
1707
1708 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1709 {
1710         struct dn_route *rt = v;
1711         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1712
1713         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1714                         rt->u.dst.dev ? rt->u.dst.dev->name : "*",
1715                         dn_addr2asc(dn_ntohs(rt->rt_daddr), buf1),
1716                         dn_addr2asc(dn_ntohs(rt->rt_saddr), buf2),
1717                         atomic_read(&rt->u.dst.__refcnt),
1718                         rt->u.dst.__use,
1719                         (int) dst_metric(&rt->u.dst, RTAX_RTT));
1720         return 0;
1721 }
1722
1723 static const struct seq_operations dn_rt_cache_seq_ops = {
1724         .start  = dn_rt_cache_seq_start,
1725         .next   = dn_rt_cache_seq_next,
1726         .stop   = dn_rt_cache_seq_stop,
1727         .show   = dn_rt_cache_seq_show,
1728 };
1729
1730 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1731 {
1732         return seq_open_private(file, &dn_rt_cache_seq_ops,
1733                         sizeof(struct dn_rt_cache_iter_state));
1734 }
1735
1736 static const struct file_operations dn_rt_cache_seq_fops = {
1737         .owner   = THIS_MODULE,
1738         .open    = dn_rt_cache_seq_open,
1739         .read    = seq_read,
1740         .llseek  = seq_lseek,
1741         .release = seq_release_private,
1742 };
1743
1744 #endif /* CONFIG_PROC_FS */
1745
1746 void __init dn_route_init(void)
1747 {
1748         int i, goal, order;
1749
1750         dn_dst_ops.kmem_cachep =
1751                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1752                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1753         setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1754         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1755         add_timer(&dn_route_timer);
1756
1757         goal = num_physpages >> (26 - PAGE_SHIFT);
1758
1759         for(order = 0; (1UL << order) < goal; order++)
1760                 /* NOTHING */;
1761
1762         /*
1763          * Only want 1024 entries max, since the table is very, very unlikely
1764          * to be larger than that.
1765          */
1766         while(order && ((((1UL << order) * PAGE_SIZE) /
1767                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1768                 order--;
1769
1770         do {
1771                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1772                         sizeof(struct dn_rt_hash_bucket);
1773                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1774                         dn_rt_hash_mask--;
1775                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1776                         __get_free_pages(GFP_ATOMIC, order);
1777         } while (dn_rt_hash_table == NULL && --order > 0);
1778
1779         if (!dn_rt_hash_table)
1780                 panic("Failed to allocate DECnet route cache hash table\n");
1781
1782         printk(KERN_INFO
1783                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1784                 dn_rt_hash_mask,
1785                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1786
1787         dn_rt_hash_mask--;
1788         for(i = 0; i <= dn_rt_hash_mask; i++) {
1789                 spin_lock_init(&dn_rt_hash_table[i].lock);
1790                 dn_rt_hash_table[i].chain = NULL;
1791         }
1792
1793         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1794
1795         proc_net_fops_create(&init_net, "decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1796
1797 #ifdef CONFIG_DECNET_ROUTER
1798         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute, dn_fib_dump);
1799 #else
1800         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1801                       dn_cache_dump);
1802 #endif
1803 }
1804
1805 void __exit dn_route_cleanup(void)
1806 {
1807         del_timer(&dn_route_timer);
1808         dn_run_flush(0);
1809
1810         proc_net_remove(&init_net, "decnet_cache");
1811 }
1812