net/decnet/dn_route.c

   1 /*
   2  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   3  *              operating system.  DECnet is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              DECnet Routing Functions (Endnode and Router)
   7  *
   8  * Authors:     Steve Whitehouse <SteveW@ACM.org>
   9  *              Eduardo Marcelo Serrat <emserrat@geocities.com>
  10  *
  11  * Changes:
  12  *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
  13  *                                 "return-to-sender" bits on outgoing
  14  *                                 packets.
  15  *              Steve Whitehouse : Timeouts for cached routes.
  16  *              Steve Whitehouse : Use dst cache for input routes too.
  17  *              Steve Whitehouse : Fixed error values in dn_send_skb.
  18  *              Steve Whitehouse : Rework routing functions to better fit
  19  *                                 DECnet routing design
  20  *              Alexey Kuznetsov : New SMP locking
  21  *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
  22  *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
  23  *                                 Fixed possible skb leak in rtnetlink funcs.
  24  *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
  25  *                                 Alexey Kuznetsov's finer grained locking
  26  *                                 from ipv4/route.c.
  27  *              Steve Whitehouse : Routing is now starting to look like a
  28  *                                 sensible set of code now, mainly due to
  29  *                                 my copying the IPv4 routing code. The
  30  *                                 hooks here are modified and will continue
  31  *                                 to evolve for a while.
  32  *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
  33  *                                 stuff. Look out raw sockets your days
  34  *                                 are numbered!
  35  *              Steve Whitehouse : Added return-to-sender functions. Added
  36  *                                 backlog congestion level return codes.
  37  *              Steve Whitehouse : Fixed bug where routes were set up with
  38  *                                 no ref count on net devices.
  39  *              Steve Whitehouse : RCU for the route cache
  40  *              Steve Whitehouse : Preparations for the flow cache
  41  *              Steve Whitehouse : Prepare for nonlinear skbs
  42  */
  43
  44 /******************************************************************************
  45     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
  46
  47     This program is free software; you can redistribute it and/or modify
  48     it under the terms of the GNU General Public License as published by
  49     the Free Software Foundation; either version 2 of the License, or
  50     any later version.
  51
  52     This program is distributed in the hope that it will be useful,
  53     but WITHOUT ANY WARRANTY; without even the implied warranty of
  54     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  55     GNU General Public License for more details.
  56 *******************************************************************************/
  57
  58 #include <linux/errno.h>
  59 #include <linux/types.h>
  60 #include <linux/socket.h>
  61 #include <linux/in.h>
  62 #include <linux/kernel.h>
  63 #include <linux/sockios.h>
  64 #include <linux/net.h>
  65 #include <linux/netdevice.h>
  66 #include <linux/inet.h>
  67 #include <linux/route.h>
  68 #include <linux/in_route.h>
  69 #include <linux/slab.h>
  70 #include <net/sock.h>
  71 #include <linux/mm.h>
  72 #include <linux/proc_fs.h>
  73 #include <linux/seq_file.h>
  74 #include <linux/init.h>
  75 #include <linux/rtnetlink.h>
  76 #include <linux/string.h>
  77 #include <linux/netfilter_decnet.h>
  78 #include <linux/rcupdate.h>
  79 #include <linux/times.h>
  80 #include <asm/errno.h>
  81 #include <net/net_namespace.h>
  82 #include <net/netlink.h>
  83 #include <net/neighbour.h>
  84 #include <net/dst.h>
  85 #include <net/flow.h>
  86 #include <net/fib_rules.h>
  87 #include <net/dn.h>
  88 #include <net/dn_dev.h>
  89 #include <net/dn_nsp.h>
  90 #include <net/dn_route.h>
  91 #include <net/dn_neigh.h>
  92 #include <net/dn_fib.h>
  93
  94 struct dn_rt_hash_bucket
  95 {
  96         struct dn_route *chain;
  97         spinlock_t lock;
  98 };
  99
 100 extern struct neigh_table dn_neigh_table;
 101
 102
 103 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 104
 105 static const int dn_rt_min_delay = 2 * HZ;
 106 static const int dn_rt_max_delay = 10 * HZ;
 107 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 108
 109 static unsigned long dn_rt_deadline;
 110
 111 static int dn_dst_gc(struct dst_ops *ops);
 112 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 113 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 114 static void dn_dst_link_failure(struct sk_buff *);
 115 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
 116 static int dn_route_input(struct sk_buff *);
 117 static void dn_run_flush(unsigned long dummy);
 118
 119 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 120 static unsigned dn_rt_hash_mask;
 121
 122 static struct timer_list dn_route_timer;
 123 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 124 int decnet_dst_gc_interval = 2;
 125
 126 static struct dst_ops dn_dst_ops = {
 127         .family =               PF_DECnet,
 128         .protocol =             cpu_to_be16(ETH_P_DNA_RT),
 129         .gc_thresh =            128,
 130         .gc =                   dn_dst_gc,
 131         .check =                dn_dst_check,
 132         .negative_advice =      dn_dst_negative_advice,
 133         .link_failure =         dn_dst_link_failure,
 134         .update_pmtu =          dn_dst_update_pmtu,
 135         .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 }
 268
 269 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
 270 {
 271         return ((fl1->nl_u.dn_u.daddr ^ fl2->nl_u.dn_u.daddr) |
 272                 (fl1->nl_u.dn_u.saddr ^ fl2->nl_u.dn_u.saddr) |
 273                 (fl1->mark ^ fl2->mark) |
 274                 (fl1->nl_u.dn_u.scope ^ fl2->nl_u.dn_u.scope) |
 275                 (fl1->oif ^ fl2->oif) |
 276                 (fl1->iif ^ fl2->iif)) == 0;
 277 }
 278
 279 static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
 280 {
 281         struct dn_route *rth, **rthp;
 282         unsigned long now = jiffies;
 283
 284         rthp = &dn_rt_hash_table[hash].chain;
 285
 286         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 287         while((rth = *rthp) != NULL) {
 288                 if (compare_keys(&rth->fl, &rt->fl)) {
 289                         /* Put it first */
 290                         *rthp = rth->u.dst.dn_next;
 291                         rcu_assign_pointer(rth->u.dst.dn_next,
 292                                            dn_rt_hash_table[hash].chain);
 293                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 294
 295                         dst_use(&rth->u.dst, now);
 296                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 297
 298                         dnrt_drop(rt);
 299                         *rp = rth;
 300                         return 0;
 301                 }
 302                 rthp = &rth->u.dst.dn_next;
 303         }
 304
 305         rcu_assign_pointer(rt->u.dst.dn_next, dn_rt_hash_table[hash].chain);
 306         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 307
 308         dst_use(&rt->u.dst, now);
 309         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 310         *rp = rt;
 311         return 0;
 312 }
 313
 314 static void dn_run_flush(unsigned long dummy)
 315 {
 316         int i;
 317         struct dn_route *rt, *next;
 318
 319         for(i = 0; i < dn_rt_hash_mask; i++) {
 320                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 321
 322                 if ((rt = xchg(&dn_rt_hash_table[i].chain, NULL)) == NULL)
 323                         goto nothing_to_declare;
 324
 325                 for(; rt; rt=next) {
 326                         next = rt->u.dst.dn_next;
 327                         rt->u.dst.dn_next = NULL;
 328                         dst_free((struct dst_entry *)rt);
 329                 }
 330
 331 nothing_to_declare:
 332                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 333         }
 334 }
 335
 336 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 337
 338 void dn_rt_cache_flush(int delay)
 339 {
 340         unsigned long now = jiffies;
 341         int user_mode = !in_interrupt();
 342
 343         if (delay < 0)
 344                 delay = dn_rt_min_delay;
 345
 346         spin_lock_bh(&dn_rt_flush_lock);
 347
 348         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 349                 long tmo = (long)(dn_rt_deadline - now);
 350
 351                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 352                         tmo = 0;
 353
 354                 if (delay > tmo)
 355                         delay = tmo;
 356         }
 357
 358         if (delay <= 0) {
 359                 spin_unlock_bh(&dn_rt_flush_lock);
 360                 dn_run_flush(0);
 361                 return;
 362         }
 363
 364         if (dn_rt_deadline == 0)
 365                 dn_rt_deadline = now + dn_rt_max_delay;
 366
 367         dn_rt_flush_timer.expires = now + delay;
 368         add_timer(&dn_rt_flush_timer);
 369         spin_unlock_bh(&dn_rt_flush_lock);
 370 }
 371
 372 /**
 373  * dn_return_short - Return a short packet to its sender
 374  * @skb: The packet to return
 375  *
 376  */
 377 static int dn_return_short(struct sk_buff *skb)
 378 {
 379         struct dn_skb_cb *cb;
 380         unsigned char *ptr;
 381         __le16 *src;
 382         __le16 *dst;
 383
 384         /* Add back headers */
 385         skb_push(skb, skb->data - skb_network_header(skb));
 386
 387         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 388                 return NET_RX_DROP;
 389
 390         cb = DN_SKB_CB(skb);
 391         /* Skip packet length and point to flags */
 392         ptr = skb->data + 2;
 393         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 394
 395         dst = (__le16 *)ptr;
 396         ptr += 2;
 397         src = (__le16 *)ptr;
 398         ptr += 2;
 399         *ptr = 0; /* Zero hop count */
 400
 401         swap(*src, *dst);
 402
 403         skb->pkt_type = PACKET_OUTGOING;
 404         dn_rt_finish_output(skb, NULL, NULL);
 405         return NET_RX_SUCCESS;
 406 }
 407
 408 /**
 409  * dn_return_long - Return a long packet to its sender
 410  * @skb: The long format packet to return
 411  *
 412  */
 413 static int dn_return_long(struct sk_buff *skb)
 414 {
 415         struct dn_skb_cb *cb;
 416         unsigned char *ptr;
 417         unsigned char *src_addr, *dst_addr;
 418         unsigned char tmp[ETH_ALEN];
 419
 420         /* Add back all headers */
 421         skb_push(skb, skb->data - skb_network_header(skb));
 422
 423         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 424                 return NET_RX_DROP;
 425
 426         cb = DN_SKB_CB(skb);
 427         /* Ignore packet length and point to flags */
 428         ptr = skb->data + 2;
 429
 430         /* Skip padding */
 431         if (*ptr & DN_RT_F_PF) {
 432                 char padlen = (*ptr & ~DN_RT_F_PF);
 433                 ptr += padlen;
 434         }
 435
 436         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 437         ptr += 2;
 438         dst_addr = ptr;
 439         ptr += 8;
 440         src_addr = ptr;
 441         ptr += 6;
 442         *ptr = 0; /* Zero hop count */
 443
 444         /* Swap source and destination */
 445         memcpy(tmp, src_addr, ETH_ALEN);
 446         memcpy(src_addr, dst_addr, ETH_ALEN);
 447         memcpy(dst_addr, tmp, ETH_ALEN);
 448
 449         skb->pkt_type = PACKET_OUTGOING;
 450         dn_rt_finish_output(skb, dst_addr, src_addr);
 451         return NET_RX_SUCCESS;
 452 }
 453
 454 /**
 455  * dn_route_rx_packet - Try and find a route for an incoming packet
 456  * @skb: The packet to find a route for
 457  *
 458  * Returns: result of input function if route is found, error code otherwise
 459  */
 460 static int dn_route_rx_packet(struct sk_buff *skb)
 461 {
 462         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 463         int err;
 464
 465         if ((err = dn_route_input(skb)) == 0)
 466                 return dst_input(skb);
 467
 468         if (decnet_debug_level & 4) {
 469                 char *devname = skb->dev ? skb->dev->name : "???";
 470                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 471                 printk(KERN_DEBUG
 472                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 473                         (int)cb->rt_flags, devname, skb->len,
 474                         le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
 475                         err, skb->pkt_type);
 476         }
 477
 478         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 479                 switch(cb->rt_flags & DN_RT_PKT_MSK) {
 480                         case DN_RT_PKT_SHORT:
 481                                 return dn_return_short(skb);
 482                         case DN_RT_PKT_LONG:
 483                                 return dn_return_long(skb);
 484                 }
 485         }
 486
 487         kfree_skb(skb);
 488         return NET_RX_DROP;
 489 }
 490
 491 static int dn_route_rx_long(struct sk_buff *skb)
 492 {
 493         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 494         unsigned char *ptr = skb->data;
 495
 496         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 497                 goto drop_it;
 498
 499         skb_pull(skb, 20);
 500         skb_reset_transport_header(skb);
 501
 502         /* Destination info */
 503         ptr += 2;
 504         cb->dst = dn_eth2dn(ptr);
 505         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 506                 goto drop_it;
 507         ptr += 6;
 508
 509
 510         /* Source info */
 511         ptr += 2;
 512         cb->src = dn_eth2dn(ptr);
 513         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 514                 goto drop_it;
 515         ptr += 6;
 516         /* Other junk */
 517         ptr++;
 518         cb->hops = *ptr++; /* Visit Count */
 519
 520         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 521                        dn_route_rx_packet);
 522
 523 drop_it:
 524         kfree_skb(skb);
 525         return NET_RX_DROP;
 526 }
 527
 528
 529
 530 static int dn_route_rx_short(struct sk_buff *skb)
 531 {
 532         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 533         unsigned char *ptr = skb->data;
 534
 535         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 536                 goto drop_it;
 537
 538         skb_pull(skb, 5);
 539         skb_reset_transport_header(skb);
 540
 541         cb->dst = *(__le16 *)ptr;
 542         ptr += 2;
 543         cb->src = *(__le16 *)ptr;
 544         ptr += 2;
 545         cb->hops = *ptr & 0x3f;
 546
 547         return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
 548                        dn_route_rx_packet);
 549
 550 drop_it:
 551         kfree_skb(skb);
 552         return NET_RX_DROP;
 553 }
 554
 555 static int dn_route_discard(struct sk_buff *skb)
 556 {
 557         /*
 558          * I know we drop the packet here, but thats considered success in
 559          * this case
 560          */
 561         kfree_skb(skb);
 562         return NET_RX_SUCCESS;
 563 }
 564
 565 static int dn_route_ptp_hello(struct sk_buff *skb)
 566 {
 567         dn_dev_hello(skb);
 568         dn_neigh_pointopoint_hello(skb);
 569         return NET_RX_SUCCESS;
 570 }
 571
 572 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 573 {
 574         struct dn_skb_cb *cb;
 575         unsigned char flags = 0;
 576         __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 577         struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
 578         unsigned char padlen = 0;
 579
 580         if (!net_eq(dev_net(dev), &init_net))
 581                 goto dump_it;
 582
 583         if (dn == NULL)
 584                 goto dump_it;
 585
 586         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 587                 goto out;
 588
 589         if (!pskb_may_pull(skb, 3))
 590                 goto dump_it;
 591
 592         skb_pull(skb, 2);
 593
 594         if (len > skb->len)
 595                 goto dump_it;
 596
 597         skb_trim(skb, len);
 598
 599         flags = *skb->data;
 600
 601         cb = DN_SKB_CB(skb);
 602         cb->stamp = jiffies;
 603         cb->iif = dev->ifindex;
 604
 605         /*
 606          * If we have padding, remove it.
 607          */
 608         if (flags & DN_RT_F_PF) {
 609                 padlen = flags & ~DN_RT_F_PF;
 610                 if (!pskb_may_pull(skb, padlen + 1))
 611                         goto dump_it;
 612                 skb_pull(skb, padlen);
 613                 flags = *skb->data;
 614         }
 615
 616         skb_reset_network_header(skb);
 617
 618         /*
 619          * Weed out future version DECnet
 620          */
 621         if (flags & DN_RT_F_VER)
 622                 goto dump_it;
 623
 624         cb->rt_flags = flags;
 625
 626         if (decnet_debug_level & 1)
 627                 printk(KERN_DEBUG
 628                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 629                         (int)flags, (dev) ? dev->name : "???", len, skb->len,
 630                         padlen);
 631
 632         if (flags & DN_RT_PKT_CNTL) {
 633                 if (unlikely(skb_linearize(skb)))
 634                         goto dump_it;
 635
 636                 switch(flags & DN_RT_CNTL_MSK) {
 637                         case DN_RT_PKT_INIT:
 638                                 dn_dev_init_pkt(skb);
 639                                 break;
 640                         case DN_RT_PKT_VERI:
 641                                 dn_dev_veri_pkt(skb);
 642                                 break;
 643                 }
 644
 645                 if (dn->parms.state != DN_DEV_S_RU)
 646                         goto dump_it;
 647
 648                 switch(flags & DN_RT_CNTL_MSK) {
 649                         case DN_RT_PKT_HELO:
 650                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 651                                                skb, skb->dev, NULL,
 652                                                dn_route_ptp_hello);
 653
 654                         case DN_RT_PKT_L1RT:
 655                         case DN_RT_PKT_L2RT:
 656                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
 657                                                skb, skb->dev, NULL,
 658                                                dn_route_discard);
 659                         case DN_RT_PKT_ERTH:
 660                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 661                                                skb, skb->dev, NULL,
 662                                                dn_neigh_router_hello);
 663
 664                         case DN_RT_PKT_EEDH:
 665                                 return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
 666                                                skb, skb->dev, NULL,
 667                                                dn_neigh_endnode_hello);
 668                 }
 669         } else {
 670                 if (dn->parms.state != DN_DEV_S_RU)
 671                         goto dump_it;
 672
 673                 skb_pull(skb, 1); /* Pull flags */
 674
 675                 switch(flags & DN_RT_PKT_MSK) {
 676                         case DN_RT_PKT_LONG:
 677                                 return dn_route_rx_long(skb);
 678                         case DN_RT_PKT_SHORT:
 679                                 return dn_route_rx_short(skb);
 680                 }
 681         }
 682
 683 dump_it:
 684         kfree_skb(skb);
 685 out:
 686         return NET_RX_DROP;
 687 }
 688
 689 static int dn_output(struct sk_buff *skb)
 690 {
 691         struct dst_entry *dst = skb_dst(skb);
 692         struct dn_route *rt = (struct dn_route *)dst;
 693         struct net_device *dev = dst->dev;
 694         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 695         struct neighbour *neigh;
 696
 697         int err = -EINVAL;
 698
 699         if ((neigh = dst->neighbour) == NULL)
 700                 goto error;
 701
 702         skb->dev = dev;
 703
 704         cb->src = rt->rt_saddr;
 705         cb->dst = rt->rt_daddr;
 706
 707         /*
 708          * Always set the Intra-Ethernet bit on all outgoing packets
 709          * originated on this node. Only valid flag from upper layers
 710          * is return-to-sender-requested. Set hop count to 0 too.
 711          */
 712         cb->rt_flags &= ~DN_RT_F_RQR;
 713         cb->rt_flags |= DN_RT_F_IE;
 714         cb->hops = 0;
 715
 716         return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, skb, NULL, dev,
 717                        neigh->output);
 718
 719 error:
 720         if (net_ratelimit())
 721                 printk(KERN_DEBUG "dn_output: This should not happen\n");
 722
 723         kfree_skb(skb);
 724
 725         return err;
 726 }
 727
 728 static int dn_forward(struct sk_buff *skb)
 729 {
 730         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 731         struct dst_entry *dst = skb_dst(skb);
 732         struct dn_dev *dn_db = dst->dev->dn_ptr;
 733         struct dn_route *rt;
 734         struct neighbour *neigh = dst->neighbour;
 735         int header_len;
 736 #ifdef CONFIG_NETFILTER
 737         struct net_device *dev = skb->dev;
 738 #endif
 739
 740         if (skb->pkt_type != PACKET_HOST)
 741                 goto drop;
 742
 743         /* Ensure that we have enough space for headers */
 744         rt = (struct dn_route *)skb_dst(skb);
 745         header_len = dn_db->use_long ? 21 : 6;
 746         if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+header_len))
 747                 goto drop;
 748
 749         /*
 750          * Hop count exceeded.
 751          */
 752         if (++cb->hops > 30)
 753                 goto drop;
 754
 755         skb->dev = rt->u.dst.dev;
 756
 757         /*
 758          * If packet goes out same interface it came in on, then set
 759          * the Intra-Ethernet bit. This has no effect for short
 760          * packets, so we don't need to test for them here.
 761          */
 762         cb->rt_flags &= ~DN_RT_F_IE;
 763         if (rt->rt_flags & RTCF_DOREDIRECT)
 764                 cb->rt_flags |= DN_RT_F_IE;
 765
 766         return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, skb, dev, skb->dev,
 767                        neigh->output);
 768
 769 drop:
 770         kfree_skb(skb);
 771         return NET_RX_DROP;
 772 }
 773
 774 /*
 775  * Used to catch bugs. This should never normally get
 776  * called.
 777  */
 778 static int dn_rt_bug(struct sk_buff *skb)
 779 {
 780         if (net_ratelimit()) {
 781                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 782
 783                 printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
 784                                 le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 785         }
 786
 787         kfree_skb(skb);
 788
 789         return NET_RX_DROP;
 790 }
 791
 792 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 793 {
 794         struct dn_fib_info *fi = res->fi;
 795         struct net_device *dev = rt->u.dst.dev;
 796         struct neighbour *n;
 797         unsigned mss;
 798
 799         if (fi) {
 800                 if (DN_FIB_RES_GW(*res) &&
 801                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 802                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 803                 memcpy(rt->u.dst.metrics, fi->fib_metrics,
 804                        sizeof(rt->u.dst.metrics));
 805         }
 806         rt->rt_type = res->type;
 807
 808         if (dev != NULL && rt->u.dst.neighbour == NULL) {
 809                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 810                 if (IS_ERR(n))
 811                         return PTR_ERR(n);
 812                 rt->u.dst.neighbour = n;
 813         }
 814
 815         if (dst_metric(&rt->u.dst, RTAX_MTU) == 0 ||
 816             dst_metric(&rt->u.dst, RTAX_MTU) > rt->u.dst.dev->mtu)
 817                 rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
 818         mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->u.dst));
 819         if (dst_metric(&rt->u.dst, RTAX_ADVMSS) == 0 ||
 820             dst_metric(&rt->u.dst, RTAX_ADVMSS) > mss)
 821                 rt->u.dst.metrics[RTAX_ADVMSS-1] = mss;
 822         return 0;
 823 }
 824
 825 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 826 {
 827         __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 828         int match = 16;
 829         while(tmp) {
 830                 tmp >>= 1;
 831                 match--;
 832         }
 833         return match;
 834 }
 835
 836 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 837 {
 838         __le16 saddr = 0;
 839         struct dn_dev *dn_db = dev->dn_ptr;
 840         struct dn_ifaddr *ifa;
 841         int best_match = 0;
 842         int ret;
 843
 844         read_lock(&dev_base_lock);
 845         for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
 846                 if (ifa->ifa_scope > scope)
 847                         continue;
 848                 if (!daddr) {
 849                         saddr = ifa->ifa_local;
 850                         break;
 851                 }
 852                 ret = dn_match_addr(daddr, ifa->ifa_local);
 853                 if (ret > best_match)
 854                         saddr = ifa->ifa_local;
 855                 if (best_match == 0)
 856                         saddr = ifa->ifa_local;
 857         }
 858         read_unlock(&dev_base_lock);
 859
 860         return saddr;
 861 }
 862
 863 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 864 {
 865         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 866 }
 867
 868 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 869 {
 870         __le16 mask = dnet_make_mask(res->prefixlen);
 871         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 872 }
 873
 874 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
 875 {
 876         struct flowi fl = { .nl_u = { .dn_u =
 877                                       { .daddr = oldflp->fld_dst,
 878                                         .saddr = oldflp->fld_src,
 879                                         .scope = RT_SCOPE_UNIVERSE,
 880                                      } },
 881                             .mark = oldflp->mark,
 882                             .iif = init_net.loopback_dev->ifindex,
 883                             .oif = oldflp->oif };
 884         struct dn_route *rt = NULL;
 885         struct net_device *dev_out = NULL, *dev;
 886         struct neighbour *neigh = NULL;
 887         unsigned hash;
 888         unsigned flags = 0;
 889         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 890         int err;
 891         int free_res = 0;
 892         __le16 gateway = 0;
 893
 894         if (decnet_debug_level & 16)
 895                 printk(KERN_DEBUG
 896                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 897                        " iif=%d oif=%d\n", le16_to_cpu(oldflp->fld_dst),
 898                        le16_to_cpu(oldflp->fld_src),
 899                        oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);
 900
 901         /* If we have an output interface, verify its a DECnet device */
 902         if (oldflp->oif) {
 903                 dev_out = dev_get_by_index(&init_net, oldflp->oif);
 904                 err = -ENODEV;
 905                 if (dev_out && dev_out->dn_ptr == NULL) {
 906                         dev_put(dev_out);
 907                         dev_out = NULL;
 908                 }
 909                 if (dev_out == NULL)
 910                         goto out;
 911         }
 912
 913         /* If we have a source address, verify that its a local address */
 914         if (oldflp->fld_src) {
 915                 err = -EADDRNOTAVAIL;
 916
 917                 if (dev_out) {
 918                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
 919                                 goto source_ok;
 920                         dev_put(dev_out);
 921                         goto out;
 922                 }
 923                 rcu_read_lock();
 924                 for_each_netdev_rcu(&init_net, dev) {
 925                         if (!dev->dn_ptr)
 926                                 continue;
 927                         if (!dn_dev_islocal(dev, oldflp->fld_src))
 928                                 continue;
 929                         if ((dev->flags & IFF_LOOPBACK) &&
 930                             oldflp->fld_dst &&
 931                             !dn_dev_islocal(dev, oldflp->fld_dst))
 932                                 continue;
 933
 934                         dev_out = dev;
 935                         break;
 936                 }
 937                 rcu_read_unlock();
 938                 if (dev_out == NULL)
 939                         goto out;
 940                 dev_hold(dev_out);
 941 source_ok:
 942                 ;
 943         }
 944
 945         /* No destination? Assume its local */
 946         if (!fl.fld_dst) {
 947                 fl.fld_dst = fl.fld_src;
 948
 949                 err = -EADDRNOTAVAIL;
 950                 if (dev_out)
 951                         dev_put(dev_out);
 952                 dev_out = init_net.loopback_dev;
 953                 dev_hold(dev_out);
 954                 if (!fl.fld_dst) {
 955                         fl.fld_dst =
 956                         fl.fld_src = dnet_select_source(dev_out, 0,
 957                                                        RT_SCOPE_HOST);
 958                         if (!fl.fld_dst)
 959                                 goto out;
 960                 }
 961                 fl.oif = init_net.loopback_dev->ifindex;
 962                 res.type = RTN_LOCAL;
 963                 goto make_route;
 964         }
 965
 966         if (decnet_debug_level & 16)
 967                 printk(KERN_DEBUG
 968                        "dn_route_output_slow: initial checks complete."
 969                        " dst=%o4x src=%04x oif=%d try_hard=%d\n",
 970                        le16_to_cpu(fl.fld_dst), le16_to_cpu(fl.fld_src),
 971                        fl.oif, try_hard);
 972
 973         /*
 974          * N.B. If the kernel is compiled without router support then
 975          * dn_fib_lookup() will evaluate to non-zero so this if () block
 976          * will always be executed.
 977          */
 978         err = -ESRCH;
 979         if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
 980                 struct dn_dev *dn_db;
 981                 if (err != -ESRCH)
 982                         goto out;
 983                 /*
 984                  * Here the fallback is basically the standard algorithm for
 985                  * routing in endnodes which is described in the DECnet routing
 986                  * docs
 987                  *
 988                  * If we are not trying hard, look in neighbour cache.
 989                  * The result is tested to ensure that if a specific output
 990                  * device/source address was requested, then we honour that
 991                  * here
 992                  */
 993                 if (!try_hard) {
 994                         neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fl.fld_dst);
 995                         if (neigh) {
 996                                 if ((oldflp->oif &&
 997                                     (neigh->dev->ifindex != oldflp->oif)) ||
 998                                     (oldflp->fld_src &&
 999                                     (!dn_dev_islocal(neigh->dev,
1000                                                       oldflp->fld_src)))) {
1001                                         neigh_release(neigh);
1002                                         neigh = NULL;
1003                                 } else {
1004                                         if (dev_out)
1005                                                 dev_put(dev_out);
1006                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
1007                                                 dev_out = init_net.loopback_dev;
1008                                                 res.type = RTN_LOCAL;
1009                                         } else {
1010                                                 dev_out = neigh->dev;
1011                                         }
1012                                         dev_hold(dev_out);
1013                                         goto select_source;
1014                                 }
1015                         }
1016                 }
1017
1018                 /* Not there? Perhaps its a local address */
1019                 if (dev_out == NULL)
1020                         dev_out = dn_dev_get_default();
1021                 err = -ENODEV;
1022                 if (dev_out == NULL)
1023                         goto out;
1024                 dn_db = dev_out->dn_ptr;
1025                 /* Possible improvement - check all devices for local addr */
1026                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1027                         dev_put(dev_out);
1028                         dev_out = init_net.loopback_dev;
1029                         dev_hold(dev_out);
1030                         res.type = RTN_LOCAL;
1031                         goto select_source;
1032                 }
1033                 /* Not local either.... try sending it to the default router */
1034                 neigh = neigh_clone(dn_db->router);
1035                 BUG_ON(neigh && neigh->dev != dev_out);
1036
1037                 /* Ok then, we assume its directly connected and move on */
1038 select_source:
1039                 if (neigh)
1040                         gateway = ((struct dn_neigh *)neigh)->addr;
1041                 if (gateway == 0)
1042                         gateway = fl.fld_dst;
1043                 if (fl.fld_src == 0) {
1044                         fl.fld_src = dnet_select_source(dev_out, gateway,
1045                                                          res.type == RTN_LOCAL ?
1046                                                          RT_SCOPE_HOST :
1047                                                          RT_SCOPE_LINK);
1048                         if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1049                                 goto e_addr;
1050                 }
1051                 fl.oif = dev_out->ifindex;
1052                 goto make_route;
1053         }
1054         free_res = 1;
1055
1056         if (res.type == RTN_NAT)
1057                 goto e_inval;
1058
1059         if (res.type == RTN_LOCAL) {
1060                 if (!fl.fld_src)
1061                         fl.fld_src = fl.fld_dst;
1062                 if (dev_out)
1063                         dev_put(dev_out);
1064                 dev_out = init_net.loopback_dev;
1065                 dev_hold(dev_out);
1066                 fl.oif = dev_out->ifindex;
1067                 if (res.fi)
1068                         dn_fib_info_put(res.fi);
1069                 res.fi = NULL;
1070                 goto make_route;
1071         }
1072
1073         if (res.fi->fib_nhs > 1 && fl.oif == 0)
1074                 dn_fib_select_multipath(&fl, &res);
1075
1076         /*
1077          * We could add some logic to deal with default routes here and
1078          * get rid of some of the special casing above.
1079          */
1080
1081         if (!fl.fld_src)
1082                 fl.fld_src = DN_FIB_RES_PREFSRC(res);
1083
1084         if (dev_out)
1085                 dev_put(dev_out);
1086         dev_out = DN_FIB_RES_DEV(res);
1087         dev_hold(dev_out);
1088         fl.oif = dev_out->ifindex;
1089         gateway = DN_FIB_RES_GW(res);
1090
1091 make_route:
1092         if (dev_out->flags & IFF_LOOPBACK)
1093                 flags |= RTCF_LOCAL;
1094
1095         rt = dst_alloc(&dn_dst_ops);
1096         if (rt == NULL)
1097                 goto e_nobufs;
1098
1099         atomic_set(&rt->u.dst.__refcnt, 1);
1100         rt->u.dst.flags   = DST_HOST;
1101
1102         rt->fl.fld_src    = oldflp->fld_src;
1103         rt->fl.fld_dst    = oldflp->fld_dst;
1104         rt->fl.oif        = oldflp->oif;
1105         rt->fl.iif        = 0;
1106         rt->fl.mark       = oldflp->mark;
1107
1108         rt->rt_saddr      = fl.fld_src;
1109         rt->rt_daddr      = fl.fld_dst;
1110         rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1111         rt->rt_local_src  = fl.fld_src;
1112
1113         rt->rt_dst_map    = fl.fld_dst;
1114         rt->rt_src_map    = fl.fld_src;
1115
1116         rt->u.dst.dev = dev_out;
1117         dev_hold(dev_out);
1118         rt->u.dst.neighbour = neigh;
1119         neigh = NULL;
1120
1121         rt->u.dst.lastuse = jiffies;
1122         rt->u.dst.output  = dn_output;
1123         rt->u.dst.input   = dn_rt_bug;
1124         rt->rt_flags      = flags;
1125         if (flags & RTCF_LOCAL)
1126                 rt->u.dst.input = dn_nsp_rx;
1127
1128         err = dn_rt_set_next_hop(rt, &res);
1129         if (err)
1130                 goto e_neighbour;
1131
1132         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1133         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1134
1135 done:
1136         if (neigh)
1137                 neigh_release(neigh);
1138         if (free_res)
1139                 dn_fib_res_put(&res);
1140         if (dev_out)
1141                 dev_put(dev_out);
1142 out:
1143         return err;
1144
1145 e_addr:
1146         err = -EADDRNOTAVAIL;
1147         goto done;
1148 e_inval:
1149         err = -EINVAL;
1150         goto done;
1151 e_nobufs:
1152         err = -ENOBUFS;
1153         goto done;
1154 e_neighbour:
1155         dst_free(&rt->u.dst);
1156         goto e_nobufs;
1157 }
1158
1159
1160 /*
1161  * N.B. The flags may be moved into the flowi at some future stage.
1162  */
1163 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1164 {
1165         unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1166         struct dn_route *rt = NULL;
1167
1168         if (!(flags & MSG_TRYHARD)) {
1169                 rcu_read_lock_bh();
1170                 for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1171                         rt = rcu_dereference_bh(rt->u.dst.dn_next)) {
1172                         if ((flp->fld_dst == rt->fl.fld_dst) &&
1173                             (flp->fld_src == rt->fl.fld_src) &&
1174                             (flp->mark == rt->fl.mark) &&
1175                             (rt->fl.iif == 0) &&
1176                             (rt->fl.oif == flp->oif)) {
1177                                 dst_use(&rt->u.dst, jiffies);
1178                                 rcu_read_unlock_bh();
1179                                 *pprt = &rt->u.dst;
1180                                 return 0;
1181                         }
1182                 }
1183                 rcu_read_unlock_bh();
1184         }
1185
1186         return dn_route_output_slow(pprt, flp, flags);
1187 }
1188
1189 static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
1190 {
1191         int err;
1192
1193         err = __dn_route_output_key(pprt, flp, flags);
1194         if (err == 0 && flp->proto) {
1195                 err = xfrm_lookup(&init_net, pprt, flp, NULL, 0);
1196         }
1197         return err;
1198 }
1199
1200 int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
1201 {
1202         int err;
1203
1204         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1205         if (err == 0 && fl->proto) {
1206                 err = xfrm_lookup(&init_net, pprt, fl, sk,
1207                                  (flags & MSG_DONTWAIT) ? 0 : XFRM_LOOKUP_WAIT);
1208         }
1209         return err;
1210 }
1211
1212 static int dn_route_input_slow(struct sk_buff *skb)
1213 {
1214         struct dn_route *rt = NULL;
1215         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1216         struct net_device *in_dev = skb->dev;
1217         struct net_device *out_dev = NULL;
1218         struct dn_dev *dn_db;
1219         struct neighbour *neigh = NULL;
1220         unsigned hash;
1221         int flags = 0;
1222         __le16 gateway = 0;
1223         __le16 local_src = 0;
1224         struct flowi fl = { .nl_u = { .dn_u =
1225                                      { .daddr = cb->dst,
1226                                        .saddr = cb->src,
1227                                        .scope = RT_SCOPE_UNIVERSE,
1228                                     } },
1229                             .mark = skb->mark,
1230                             .iif = skb->dev->ifindex };
1231         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1232         int err = -EINVAL;
1233         int free_res = 0;
1234
1235         dev_hold(in_dev);
1236
1237         if ((dn_db = in_dev->dn_ptr) == NULL)
1238                 goto out;
1239
1240         /* Zero source addresses are not allowed */
1241         if (fl.fld_src == 0)
1242                 goto out;
1243
1244         /*
1245          * In this case we've just received a packet from a source
1246          * outside ourselves pretending to come from us. We don't
1247          * allow it any further to prevent routing loops, spoofing and
1248          * other nasties. Loopback packets already have the dst attached
1249          * so this only affects packets which have originated elsewhere.
1250          */
1251         err  = -ENOTUNIQ;
1252         if (dn_dev_islocal(in_dev, cb->src))
1253                 goto out;
1254
1255         err = dn_fib_lookup(&fl, &res);
1256         if (err) {
1257                 if (err != -ESRCH)
1258                         goto out;
1259                 /*
1260                  * Is the destination us ?
1261                  */
1262                 if (!dn_dev_islocal(in_dev, cb->dst))
1263                         goto e_inval;
1264
1265                 res.type = RTN_LOCAL;
1266         } else {
1267                 __le16 src_map = fl.fld_src;
1268                 free_res = 1;
1269
1270                 out_dev = DN_FIB_RES_DEV(res);
1271                 if (out_dev == NULL) {
1272                         if (net_ratelimit())
1273                                 printk(KERN_CRIT "Bug in dn_route_input_slow() "
1274                                                  "No output device\n");
1275                         goto e_inval;
1276                 }
1277                 dev_hold(out_dev);
1278
1279                 if (res.r)
1280                         src_map = fl.fld_src; /* no NAT support for now */
1281
1282                 gateway = DN_FIB_RES_GW(res);
1283                 if (res.type == RTN_NAT) {
1284                         fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1285                         dn_fib_res_put(&res);
1286                         free_res = 0;
1287                         if (dn_fib_lookup(&fl, &res))
1288                                 goto e_inval;
1289                         free_res = 1;
1290                         if (res.type != RTN_UNICAST)
1291                                 goto e_inval;
1292                         flags |= RTCF_DNAT;
1293                         gateway = fl.fld_dst;
1294                 }
1295                 fl.fld_src = src_map;
1296         }
1297
1298         switch(res.type) {
1299         case RTN_UNICAST:
1300                 /*
1301                  * Forwarding check here, we only check for forwarding
1302                  * being turned off, if you want to only forward intra
1303                  * area, its up to you to set the routing tables up
1304                  * correctly.
1305                  */
1306                 if (dn_db->parms.forwarding == 0)
1307                         goto e_inval;
1308
1309                 if (res.fi->fib_nhs > 1 && fl.oif == 0)
1310                         dn_fib_select_multipath(&fl, &res);
1311
1312                 /*
1313                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1314                  * flag as a hint to set the intra-ethernet bit when
1315                  * forwarding. If we've got NAT in operation, we don't do
1316                  * this optimisation.
1317                  */
1318                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1319                         flags |= RTCF_DOREDIRECT;
1320
1321                 local_src = DN_FIB_RES_PREFSRC(res);
1322
1323         case RTN_BLACKHOLE:
1324         case RTN_UNREACHABLE:
1325                 break;
1326         case RTN_LOCAL:
1327                 flags |= RTCF_LOCAL;
1328                 fl.fld_src = cb->dst;
1329                 fl.fld_dst = cb->src;
1330
1331                 /* Routing tables gave us a gateway */
1332                 if (gateway)
1333                         goto make_route;
1334
1335                 /* Packet was intra-ethernet, so we know its on-link */
1336                 if (cb->rt_flags & DN_RT_F_IE) {
1337                         gateway = cb->src;
1338                         flags |= RTCF_DIRECTSRC;
1339                         goto make_route;
1340                 }
1341
1342                 /* Use the default router if there is one */
1343                 neigh = neigh_clone(dn_db->router);
1344                 if (neigh) {
1345                         gateway = ((struct dn_neigh *)neigh)->addr;
1346                         goto make_route;
1347                 }
1348
1349                 /* Close eyes and pray */
1350                 gateway = cb->src;
1351                 flags |= RTCF_DIRECTSRC;
1352                 goto make_route;
1353         default:
1354                 goto e_inval;
1355         }
1356
1357 make_route:
1358         rt = dst_alloc(&dn_dst_ops);
1359         if (rt == NULL)
1360                 goto e_nobufs;
1361
1362         rt->rt_saddr      = fl.fld_src;
1363         rt->rt_daddr      = fl.fld_dst;
1364         rt->rt_gateway    = fl.fld_dst;
1365         if (gateway)
1366                 rt->rt_gateway = gateway;
1367         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1368
1369         rt->rt_dst_map    = fl.fld_dst;
1370         rt->rt_src_map    = fl.fld_src;
1371
1372         rt->fl.fld_src    = cb->src;
1373         rt->fl.fld_dst    = cb->dst;
1374         rt->fl.oif        = 0;
1375         rt->fl.iif        = in_dev->ifindex;
1376         rt->fl.mark       = fl.mark;
1377
1378         rt->u.dst.flags = DST_HOST;
1379         rt->u.dst.neighbour = neigh;
1380         rt->u.dst.dev = out_dev;
1381         rt->u.dst.lastuse = jiffies;
1382         rt->u.dst.output = dn_rt_bug;
1383         switch(res.type) {
1384                 case RTN_UNICAST:
1385                         rt->u.dst.input = dn_forward;
1386                         break;
1387                 case RTN_LOCAL:
1388                         rt->u.dst.output = dn_output;
1389                         rt->u.dst.input = dn_nsp_rx;
1390                         rt->u.dst.dev = in_dev;
1391                         flags |= RTCF_LOCAL;
1392                         break;
1393                 default:
1394                 case RTN_UNREACHABLE:
1395                 case RTN_BLACKHOLE:
1396                         rt->u.dst.input = dst_discard;
1397         }
1398         rt->rt_flags = flags;
1399         if (rt->u.dst.dev)
1400                 dev_hold(rt->u.dst.dev);
1401
1402         err = dn_rt_set_next_hop(rt, &res);
1403         if (err)
1404                 goto e_neighbour;
1405
1406         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1407         dn_insert_route(rt, hash, &rt);
1408         skb_dst_set(skb, &rt->u.dst);
1409
1410 done:
1411         if (neigh)
1412                 neigh_release(neigh);
1413         if (free_res)
1414                 dn_fib_res_put(&res);
1415         dev_put(in_dev);
1416         if (out_dev)
1417                 dev_put(out_dev);
1418 out:
1419         return err;
1420
1421 e_inval:
1422         err = -EINVAL;
1423         goto done;
1424
1425 e_nobufs:
1426         err = -ENOBUFS;
1427         goto done;
1428
1429 e_neighbour:
1430         dst_free(&rt->u.dst);
1431         goto done;
1432 }
1433
1434 static int dn_route_input(struct sk_buff *skb)
1435 {
1436         struct dn_route *rt;
1437         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1438         unsigned hash = dn_hash(cb->src, cb->dst);
1439
1440         if (skb_dst(skb))
1441                 return 0;
1442
1443         rcu_read_lock();
1444         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1445             rt = rcu_dereference(rt->u.dst.dn_next)) {
1446                 if ((rt->fl.fld_src == cb->src) &&
1447                     (rt->fl.fld_dst == cb->dst) &&
1448                     (rt->fl.oif == 0) &&
1449                     (rt->fl.mark == skb->mark) &&
1450                     (rt->fl.iif == cb->iif)) {
1451                         dst_use(&rt->u.dst, jiffies);
1452                         rcu_read_unlock();
1453                         skb_dst_set(skb, (struct dst_entry *)rt);
1454                         return 0;
1455                 }
1456         }
1457         rcu_read_unlock();
1458
1459         return dn_route_input_slow(skb);
1460 }
1461
1462 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1463                            int event, int nowait, unsigned int flags)
1464 {
1465         struct dn_route *rt = (struct dn_route *)skb_dst(skb);
1466         struct rtmsg *r;
1467         struct nlmsghdr *nlh;
1468         unsigned char *b = skb_tail_pointer(skb);
1469         long expires;
1470
1471         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1472         r = NLMSG_DATA(nlh);
1473         r->rtm_family = AF_DECnet;
1474         r->rtm_dst_len = 16;
1475         r->rtm_src_len = 0;
1476         r->rtm_tos = 0;
1477         r->rtm_table = RT_TABLE_MAIN;
1478         RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
1479         r->rtm_type = rt->rt_type;
1480         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1481         r->rtm_scope = RT_SCOPE_UNIVERSE;
1482         r->rtm_protocol = RTPROT_UNSPEC;
1483         if (rt->rt_flags & RTCF_NOTIFY)
1484                 r->rtm_flags |= RTM_F_NOTIFY;
1485         RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1486         if (rt->fl.fld_src) {
1487                 r->rtm_src_len = 16;
1488                 RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1489         }
1490         if (rt->u.dst.dev)
1491                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
1492         /*
1493          * Note to self - change this if input routes reverse direction when
1494          * they deal only with inputs and not with replies like they do
1495          * currently.
1496          */
1497         RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1498         if (rt->rt_daddr != rt->rt_gateway)
1499                 RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1500         if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
1501                 goto rtattr_failure;
1502         expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
1503         if (rtnl_put_cacheinfo(skb, &rt->u.dst, 0, 0, 0, expires,
1504                                rt->u.dst.error) < 0)
1505                 goto rtattr_failure;
1506         if (rt->fl.iif)
1507                 RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1508
1509         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1510         return skb->len;
1511
1512 nlmsg_failure:
1513 rtattr_failure:
1514         nlmsg_trim(skb, b);
1515         return -1;
1516 }
1517
1518 /*
1519  * This is called by both endnodes and routers now.
1520  */
1521 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1522 {
1523         struct net *net = sock_net(in_skb->sk);
1524         struct rtattr **rta = arg;
1525         struct rtmsg *rtm = NLMSG_DATA(nlh);
1526         struct dn_route *rt = NULL;
1527         struct dn_skb_cb *cb;
1528         int err;
1529         struct sk_buff *skb;
1530         struct flowi fl;
1531
1532         if (!net_eq(net, &init_net))
1533                 return -EINVAL;
1534
1535         memset(&fl, 0, sizeof(fl));
1536         fl.proto = DNPROTO_NSP;
1537
1538         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1539         if (skb == NULL)
1540                 return -ENOBUFS;
1541         skb_reset_mac_header(skb);
1542         cb = DN_SKB_CB(skb);
1543
1544         if (rta[RTA_SRC-1])
1545                 memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1546         if (rta[RTA_DST-1])
1547                 memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1548         if (rta[RTA_IIF-1])
1549                 memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1550
1551         if (fl.iif) {
1552                 struct net_device *dev;
1553                 if ((dev = dev_get_by_index(&init_net, fl.iif)) == NULL) {
1554                         kfree_skb(skb);
1555                         return -ENODEV;
1556                 }
1557                 if (!dev->dn_ptr) {
1558                         dev_put(dev);
1559                         kfree_skb(skb);
1560                         return -ENODEV;
1561                 }
1562                 skb->protocol = htons(ETH_P_DNA_RT);
1563                 skb->dev = dev;
1564                 cb->src = fl.fld_src;
1565                 cb->dst = fl.fld_dst;
1566                 local_bh_disable();
1567                 err = dn_route_input(skb);
1568                 local_bh_enable();
1569                 memset(cb, 0, sizeof(struct dn_skb_cb));
1570                 rt = (struct dn_route *)skb_dst(skb);
1571                 if (!err && -rt->u.dst.error)
1572                         err = rt->u.dst.error;
1573         } else {
1574                 int oif = 0;
1575                 if (rta[RTA_OIF - 1])
1576                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1577                 fl.oif = oif;
1578                 err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1579         }
1580
1581         if (skb->dev)
1582                 dev_put(skb->dev);
1583         skb->dev = NULL;
1584         if (err)
1585                 goto out_free;
1586         skb_dst_set(skb, &rt->u.dst);
1587         if (rtm->rtm_flags & RTM_F_NOTIFY)
1588                 rt->rt_flags |= RTCF_NOTIFY;
1589
1590         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1591
1592         if (err == 0)
1593                 goto out_free;
1594         if (err < 0) {
1595                 err = -EMSGSIZE;
1596                 goto out_free;
1597         }
1598
1599         return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
1600
1601 out_free:
1602         kfree_skb(skb);
1603         return err;
1604 }
1605
1606 /*
1607  * For routers, this is called from dn_fib_dump, but for endnodes its
1608  * called directly from the rtnetlink dispatch table.
1609  */
1610 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1611 {
1612         struct net *net = sock_net(skb->sk);
1613         struct dn_route *rt;
1614         int h, s_h;
1615         int idx, s_idx;
1616
1617         if (!net_eq(net, &init_net))
1618                 return 0;
1619
1620         if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1621                 return -EINVAL;
1622         if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1623                 return 0;
1624
1625         s_h = cb->args[0];
1626         s_idx = idx = cb->args[1];
1627         for(h = 0; h <= dn_rt_hash_mask; h++) {
1628                 if (h < s_h)
1629                         continue;
1630                 if (h > s_h)
1631                         s_idx = 0;
1632                 rcu_read_lock_bh();
1633                 for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1634                         rt;
1635                         rt = rcu_dereference_bh(rt->u.dst.dn_next), idx++) {
1636                         if (idx < s_idx)
1637                                 continue;
1638                         skb_dst_set(skb, dst_clone(&rt->u.dst));
1639                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1640                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1641                                         1, NLM_F_MULTI) <= 0) {
1642                                 skb_dst_drop(skb);
1643                                 rcu_read_unlock_bh();
1644                                 goto done;
1645                         }
1646                         skb_dst_drop(skb);
1647                 }
1648                 rcu_read_unlock_bh();
1649         }
1650
1651 done:
1652         cb->args[0] = h;
1653         cb->args[1] = idx;
1654         return skb->len;
1655 }
1656
1657 #ifdef CONFIG_PROC_FS
1658 struct dn_rt_cache_iter_state {
1659         int bucket;
1660 };
1661
1662 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1663 {
1664         struct dn_route *rt = NULL;
1665         struct dn_rt_cache_iter_state *s = seq->private;
1666
1667         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1668                 rcu_read_lock_bh();
1669                 rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1670                 if (rt)
1671                         break;
1672                 rcu_read_unlock_bh();
1673         }
1674         return rt;
1675 }
1676
1677 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1678 {
1679         struct dn_rt_cache_iter_state *s = seq->private;
1680
1681         rt = rt->u.dst.dn_next;
1682         while(!rt) {
1683                 rcu_read_unlock_bh();
1684                 if (--s->bucket < 0)
1685                         break;
1686                 rcu_read_lock_bh();
1687                 rt = dn_rt_hash_table[s->bucket].chain;
1688         }
1689         return rcu_dereference_bh(rt);
1690 }
1691
1692 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1693 {
1694         struct dn_route *rt = dn_rt_cache_get_first(seq);
1695
1696         if (rt) {
1697                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1698                         --*pos;
1699         }
1700         return *pos ? NULL : rt;
1701 }
1702
1703 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1704 {
1705         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1706         ++*pos;
1707         return rt;
1708 }
1709
1710 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1711 {
1712         if (v)
1713                 rcu_read_unlock_bh();
1714 }
1715
1716 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1717 {
1718         struct dn_route *rt = v;
1719         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1720
1721         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1722                         rt->u.dst.dev ? rt->u.dst.dev->name : "*",
1723                         dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1724                         dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1725                         atomic_read(&rt->u.dst.__refcnt),
1726                         rt->u.dst.__use,
1727                         (int) dst_metric(&rt->u.dst, RTAX_RTT));
1728         return 0;
1729 }
1730
1731 static const struct seq_operations dn_rt_cache_seq_ops = {
1732         .start  = dn_rt_cache_seq_start,
1733         .next   = dn_rt_cache_seq_next,
1734         .stop   = dn_rt_cache_seq_stop,
1735         .show   = dn_rt_cache_seq_show,
1736 };
1737
1738 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1739 {
1740         return seq_open_private(file, &dn_rt_cache_seq_ops,
1741                         sizeof(struct dn_rt_cache_iter_state));
1742 }
1743
1744 static const struct file_operations dn_rt_cache_seq_fops = {
1745         .owner   = THIS_MODULE,
1746         .open    = dn_rt_cache_seq_open,
1747         .read    = seq_read,
1748         .llseek  = seq_lseek,
1749         .release = seq_release_private,
1750 };
1751
1752 #endif /* CONFIG_PROC_FS */
1753
1754 void __init dn_route_init(void)
1755 {
1756         int i, goal, order;
1757
1758         dn_dst_ops.kmem_cachep =
1759                 kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1760                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1761         setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1762         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1763         add_timer(&dn_route_timer);
1764
1765         goal = totalram_pages >> (26 - PAGE_SHIFT);
1766
1767         for(order = 0; (1UL << order) < goal; order++)
1768                 /* NOTHING */;
1769
1770         /*
1771          * Only want 1024 entries max, since the table is very, very unlikely
1772          * to be larger than that.
1773          */
1774         while(order && ((((1UL << order) * PAGE_SIZE) /
1775                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1776                 order--;
1777
1778         do {
1779                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1780                         sizeof(struct dn_rt_hash_bucket);
1781                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1782                         dn_rt_hash_mask--;
1783                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1784                         __get_free_pages(GFP_ATOMIC, order);
1785         } while (dn_rt_hash_table == NULL && --order > 0);
1786
1787         if (!dn_rt_hash_table)
1788                 panic("Failed to allocate DECnet route cache hash table\n");
1789
1790         printk(KERN_INFO
1791                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1792                 dn_rt_hash_mask,
1793                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1794
1795         dn_rt_hash_mask--;
1796         for(i = 0; i <= dn_rt_hash_mask; i++) {
1797                 spin_lock_init(&dn_rt_hash_table[i].lock);
1798                 dn_rt_hash_table[i].chain = NULL;
1799         }
1800
1801         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1802
1803         proc_net_fops_create(&init_net, "decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1804
1805 #ifdef CONFIG_DECNET_ROUTER
1806         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute, dn_fib_dump);
1807 #else
1808         rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1809                       dn_cache_dump);
1810 #endif
1811 }
1812
1813 void __exit dn_route_cleanup(void)
1814 {
1815         del_timer(&dn_route_timer);
1816         dn_run_flush(0);
1817
1818         proc_net_remove(&init_net, "decnet_cache");
1819 }
1820