linux/net/decnet/dn_route.c
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   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
  93struct dn_rt_hash_bucket
  94{
  95        struct dn_route *chain;
  96        spinlock_t lock;
  97};
  98
  99extern struct neigh_table dn_neigh_table;
 100
 101
 102static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 103
 104static const int dn_rt_min_delay = 2 * HZ;
 105static const int dn_rt_max_delay = 10 * HZ;
 106static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 107
 108static unsigned long dn_rt_deadline;
 109
 110static int dn_dst_gc(struct dst_ops *ops);
 111static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 112static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 113static void dn_dst_link_failure(struct sk_buff *);
 114static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
 115static int dn_route_input(struct sk_buff *);
 116static void dn_run_flush(unsigned long dummy);
 117
 118static struct dn_rt_hash_bucket *dn_rt_hash_table;
 119static unsigned dn_rt_hash_mask;
 120
 121static struct timer_list dn_route_timer;
 122static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 123int decnet_dst_gc_interval = 2;
 124
 125static struct dst_ops dn_dst_ops = {
 126        .family =               PF_DECnet,
 127        .protocol =             cpu_to_be16(ETH_P_DNA_RT),
 128        .gc_thresh =            128,
 129        .gc =                   dn_dst_gc,
 130        .check =                dn_dst_check,
 131        .negative_advice =      dn_dst_negative_advice,
 132        .link_failure =         dn_dst_link_failure,
 133        .update_pmtu =          dn_dst_update_pmtu,
 134        .entries =              ATOMIC_INIT(0),
 135};
 136
 137static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
 138{
 139        __u16 tmp = (__u16 __force)(src ^ dst);
 140        tmp ^= (tmp >> 3);
 141        tmp ^= (tmp >> 5);
 142        tmp ^= (tmp >> 10);
 143        return dn_rt_hash_mask & (unsigned)tmp;
 144}
 145
 146static inline void dnrt_free(struct dn_route *rt)
 147{
 148        call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 149}
 150
 151static inline void dnrt_drop(struct dn_route *rt)
 152{
 153        dst_release(&rt->u.dst);
 154        call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 155}
 156
 157static void dn_dst_check_expire(unsigned long dummy)
 158{
 159        int i;
 160        struct dn_route *rt, **rtp;
 161        unsigned long now = jiffies;
 162        unsigned long expire = 120 * HZ;
 163
 164        for(i = 0; i <= dn_rt_hash_mask; i++) {
 165                rtp = &dn_rt_hash_table[i].chain;
 166
 167                spin_lock(&dn_rt_hash_table[i].lock);
 168                while((rt=*rtp) != NULL) {
 169                        if (atomic_read(&rt->u.dst.__refcnt) ||
 170                                        (now - rt->u.dst.lastuse) < expire) {
 171                                rtp = &rt->u.dst.dn_next;
 172                                continue;
 173                        }
 174                        *rtp = rt->u.dst.dn_next;
 175                        rt->u.dst.dn_next = NULL;
 176                        dnrt_free(rt);
 177                }
 178                spin_unlock(&dn_rt_hash_table[i].lock);
 179
 180                if ((jiffies - now) > 0)
 181                        break;
 182        }
 183
 184        mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 185}
 186
 187static int dn_dst_gc(struct dst_ops *ops)
 188{
 189        struct dn_route *rt, **rtp;
 190        int i;
 191        unsigned long now = jiffies;
 192        unsigned long expire = 10 * HZ;
 193
 194        for(i = 0; i <= dn_rt_hash_mask; i++) {
 195
 196                spin_lock_bh(&dn_rt_hash_table[i].lock);
 197                rtp = &dn_rt_hash_table[i].chain;
 198
 199                while((rt=*rtp) != NULL) {
 200                        if (atomic_read(&rt->u.dst.__refcnt) ||
 201                                        (now - rt->u.dst.lastuse) < expire) {
 202                                rtp = &rt->u.dst.dn_next;
 203                                continue;
 204                        }
 205                        *rtp = rt->u.dst.dn_next;
 206                        rt->u.dst.dn_next = NULL;
 207                        dnrt_drop(rt);
 208                        break;
 209                }
 210                spin_unlock_bh(&dn_rt_hash_table[i].lock);
 211        }
 212
 213        return 0;
 214}
 215
 216/*
 217 * The decnet standards don't impose a particular minimum mtu, what they
 218 * do insist on is that the routing layer accepts a datagram of at least
 219 * 230 bytes long. Here we have to subtract the routing header length from
 220 * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 221 * assume the worst and use a long header size.
 222 *
 223 * We update both the mtu and the advertised mss (i.e. the segment size we
 224 * advertise to the other end).
 225 */
 226static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
 227{
 228        u32 min_mtu = 230;
 229        struct dn_dev *dn = dst->neighbour ?
 230                            (struct dn_dev *)dst->neighbour->dev->dn_ptr : NULL;
 231
 232        if (dn && dn->use_long == 0)
 233                min_mtu -= 6;
 234        else
 235                min_mtu -= 21;
 236
 237        if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
 238                if (!(dst_metric_locked(dst, RTAX_MTU))) {
 239                        dst->metrics[RTAX_MTU-1] = mtu;
 240                        dst_set_expires(dst, dn_rt_mtu_expires);
 241                }
 242                if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 243                        u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 244                        if (dst_metric(dst, RTAX_ADVMSS) > mss)
 245                                dst->metrics[RTAX_ADVMSS-1] = mss;
 246                }
 247        }
 248}
 249
 250/*
 251 * When a route has been marked obsolete. (e.g. routing cache flush)
 252 */
 253static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 254{
 255        return NULL;
 256}
 257
 258static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 259{
 260        dst_release(dst);
 261        return NULL;
 262}
 263
 264static void dn_dst_link_failure(struct sk_buff *skb)
 265{
 266        return;
 267}
 268
 269static 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
 279static 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
 314static 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
 331nothing_to_declare:
 332                spin_unlock_bh(&dn_rt_hash_table[i].lock);
 333        }
 334}
 335
 336static DEFINE_SPINLOCK(dn_rt_flush_lock);
 337
 338void 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 */
 377static 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 */
 413static 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 */
 460static 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
 491static int dn_route_rx_long(struct sk_buff *skb)
 492{
 493        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 494        unsigned char *ptr = skb->data;
 495
 496        if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 497                goto drop_it;
 498
 499        skb_pull(skb, 20);
 500        skb_reset_transport_header(skb);
 501
 502        /* Destination info */
 503        ptr += 2;
 504        cb->dst = dn_eth2dn(ptr);
 505        if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 506                goto drop_it;
 507        ptr += 6;
 508
 509
 510        /* Source info */
 511        ptr += 2;
 512        cb->src = dn_eth2dn(ptr);
 513        if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 514                goto drop_it;
 515        ptr += 6;
 516        /* Other junk */
 517        ptr++;
 518        cb->hops = *ptr++; /* Visit Count */
 519
 520        return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
 521
 522drop_it:
 523        kfree_skb(skb);
 524        return NET_RX_DROP;
 525}
 526
 527
 528
 529static int dn_route_rx_short(struct sk_buff *skb)
 530{
 531        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 532        unsigned char *ptr = skb->data;
 533
 534        if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 535                goto drop_it;
 536
 537        skb_pull(skb, 5);
 538        skb_reset_transport_header(skb);
 539
 540        cb->dst = *(__le16 *)ptr;
 541        ptr += 2;
 542        cb->src = *(__le16 *)ptr;
 543        ptr += 2;
 544        cb->hops = *ptr & 0x3f;
 545
 546        return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
 547
 548drop_it:
 549        kfree_skb(skb);
 550        return NET_RX_DROP;
 551}
 552
 553static int dn_route_discard(struct sk_buff *skb)
 554{
 555        /*
 556         * I know we drop the packet here, but thats considered success in
 557         * this case
 558         */
 559        kfree_skb(skb);
 560        return NET_RX_SUCCESS;
 561}
 562
 563static int dn_route_ptp_hello(struct sk_buff *skb)
 564{
 565        dn_dev_hello(skb);
 566        dn_neigh_pointopoint_hello(skb);
 567        return NET_RX_SUCCESS;
 568}
 569
 570int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 571{
 572        struct dn_skb_cb *cb;
 573        unsigned char flags = 0;
 574        __u16 len = le16_to_cpu(*(__le16 *)skb->data);
 575        struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
 576        unsigned char padlen = 0;
 577
 578        if (!net_eq(dev_net(dev), &init_net))
 579                goto dump_it;
 580
 581        if (dn == NULL)
 582                goto dump_it;
 583
 584        if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 585                goto out;
 586
 587        if (!pskb_may_pull(skb, 3))
 588                goto dump_it;
 589
 590        skb_pull(skb, 2);
 591
 592        if (len > skb->len)
 593                goto dump_it;
 594
 595        skb_trim(skb, len);
 596
 597        flags = *skb->data;
 598
 599        cb = DN_SKB_CB(skb);
 600        cb->stamp = jiffies;
 601        cb->iif = dev->ifindex;
 602
 603        /*
 604         * If we have padding, remove it.
 605         */
 606        if (flags & DN_RT_F_PF) {
 607                padlen = flags & ~DN_RT_F_PF;
 608                if (!pskb_may_pull(skb, padlen + 1))
 609                        goto dump_it;
 610                skb_pull(skb, padlen);
 611                flags = *skb->data;
 612        }
 613
 614        skb_reset_network_header(skb);
 615
 616        /*
 617         * Weed out future version DECnet
 618         */
 619        if (flags & DN_RT_F_VER)
 620                goto dump_it;
 621
 622        cb->rt_flags = flags;
 623
 624        if (decnet_debug_level & 1)
 625                printk(KERN_DEBUG
 626                        "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 627                        (int)flags, (dev) ? dev->name : "???", len, skb->len,
 628                        padlen);
 629
 630        if (flags & DN_RT_PKT_CNTL) {
 631                if (unlikely(skb_linearize(skb)))
 632                        goto dump_it;
 633
 634                switch(flags & DN_RT_CNTL_MSK) {
 635                        case DN_RT_PKT_INIT:
 636                                dn_dev_init_pkt(skb);
 637                                break;
 638                        case DN_RT_PKT_VERI:
 639                                dn_dev_veri_pkt(skb);
 640                                break;
 641                }
 642
 643                if (dn->parms.state != DN_DEV_S_RU)
 644                        goto dump_it;
 645
 646                switch(flags & DN_RT_CNTL_MSK) {
 647                        case DN_RT_PKT_HELO:
 648                                return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_route_ptp_hello);
 649
 650                        case DN_RT_PKT_L1RT:
 651                        case DN_RT_PKT_L2RT:
 652                                return NF_HOOK(PF_DECnet, NF_DN_ROUTE, skb, skb->dev, NULL, dn_route_discard);
 653                        case DN_RT_PKT_ERTH:
 654                                return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_router_hello);
 655
 656                        case DN_RT_PKT_EEDH:
 657                                return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_endnode_hello);
 658                }
 659        } else {
 660                if (dn->parms.state != DN_DEV_S_RU)
 661                        goto dump_it;
 662
 663                skb_pull(skb, 1); /* Pull flags */
 664
 665                switch(flags & DN_RT_PKT_MSK) {
 666                        case DN_RT_PKT_LONG:
 667                                return dn_route_rx_long(skb);
 668                        case DN_RT_PKT_SHORT:
 669                                return dn_route_rx_short(skb);
 670                }
 671        }
 672
 673dump_it:
 674        kfree_skb(skb);
 675out:
 676        return NET_RX_DROP;
 677}
 678
 679static int dn_output(struct sk_buff *skb)
 680{
 681        struct dst_entry *dst = skb->dst;
 682        struct dn_route *rt = (struct dn_route *)dst;
 683        struct net_device *dev = dst->dev;
 684        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 685        struct neighbour *neigh;
 686
 687        int err = -EINVAL;
 688
 689        if ((neigh = dst->neighbour) == NULL)
 690                goto error;
 691
 692        skb->dev = dev;
 693
 694        cb->src = rt->rt_saddr;
 695        cb->dst = rt->rt_daddr;
 696
 697        /*
 698         * Always set the Intra-Ethernet bit on all outgoing packets
 699         * originated on this node. Only valid flag from upper layers
 700         * is return-to-sender-requested. Set hop count to 0 too.
 701         */
 702        cb->rt_flags &= ~DN_RT_F_RQR;
 703        cb->rt_flags |= DN_RT_F_IE;
 704        cb->hops = 0;
 705
 706        return NF_HOOK(PF_DECnet, NF_DN_LOCAL_OUT, skb, NULL, dev, neigh->output);
 707
 708error:
 709        if (net_ratelimit())
 710                printk(KERN_DEBUG "dn_output: This should not happen\n");
 711
 712        kfree_skb(skb);
 713
 714        return err;
 715}
 716
 717static int dn_forward(struct sk_buff *skb)
 718{
 719        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 720        struct dst_entry *dst = skb->dst;
 721        struct dn_dev *dn_db = dst->dev->dn_ptr;
 722        struct dn_route *rt;
 723        struct neighbour *neigh = dst->neighbour;
 724        int header_len;
 725#ifdef CONFIG_NETFILTER
 726        struct net_device *dev = skb->dev;
 727#endif
 728
 729        if (skb->pkt_type != PACKET_HOST)
 730                goto drop;
 731
 732        /* Ensure that we have enough space for headers */
 733        rt = (struct dn_route *)skb->dst;
 734        header_len = dn_db->use_long ? 21 : 6;
 735        if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+header_len))
 736                goto drop;
 737
 738        /*
 739         * Hop count exceeded.
 740         */
 741        if (++cb->hops > 30)
 742                goto drop;
 743
 744        skb->dev = rt->u.dst.dev;
 745
 746        /*
 747         * If packet goes out same interface it came in on, then set
 748         * the Intra-Ethernet bit. This has no effect for short
 749         * packets, so we don't need to test for them here.
 750         */
 751        cb->rt_flags &= ~DN_RT_F_IE;
 752        if (rt->rt_flags & RTCF_DOREDIRECT)
 753                cb->rt_flags |= DN_RT_F_IE;
 754
 755        return NF_HOOK(PF_DECnet, NF_DN_FORWARD, skb, dev, skb->dev, neigh->output);
 756
 757drop:
 758        kfree_skb(skb);
 759        return NET_RX_DROP;
 760}
 761
 762/*
 763 * Used to catch bugs. This should never normally get
 764 * called.
 765 */
 766static int dn_rt_bug(struct sk_buff *skb)
 767{
 768        if (net_ratelimit()) {
 769                struct dn_skb_cb *cb = DN_SKB_CB(skb);
 770
 771                printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
 772                                le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
 773        }
 774
 775        kfree_skb(skb);
 776
 777        return NET_RX_BAD;
 778}
 779
 780static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 781{
 782        struct dn_fib_info *fi = res->fi;
 783        struct net_device *dev = rt->u.dst.dev;
 784        struct neighbour *n;
 785        unsigned mss;
 786
 787        if (fi) {
 788                if (DN_FIB_RES_GW(*res) &&
 789                    DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 790                        rt->rt_gateway = DN_FIB_RES_GW(*res);
 791                memcpy(rt->u.dst.metrics, fi->fib_metrics,
 792                       sizeof(rt->u.dst.metrics));
 793        }
 794        rt->rt_type = res->type;
 795
 796        if (dev != NULL && rt->u.dst.neighbour == NULL) {
 797                n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 798                if (IS_ERR(n))
 799                        return PTR_ERR(n);
 800                rt->u.dst.neighbour = n;
 801        }
 802
 803        if (dst_metric(&rt->u.dst, RTAX_MTU) == 0 ||
 804            dst_metric(&rt->u.dst, RTAX_MTU) > rt->u.dst.dev->mtu)
 805                rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
 806        mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->u.dst));
 807        if (dst_metric(&rt->u.dst, RTAX_ADVMSS) == 0 ||
 808            dst_metric(&rt->u.dst, RTAX_ADVMSS) > mss)
 809                rt->u.dst.metrics[RTAX_ADVMSS-1] = mss;
 810        return 0;
 811}
 812
 813static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 814{
 815        __u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
 816        int match = 16;
 817        while(tmp) {
 818                tmp >>= 1;
 819                match--;
 820        }
 821        return match;
 822}
 823
 824static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 825{
 826        __le16 saddr = 0;
 827        struct dn_dev *dn_db = dev->dn_ptr;
 828        struct dn_ifaddr *ifa;
 829        int best_match = 0;
 830        int ret;
 831
 832        read_lock(&dev_base_lock);
 833        for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
 834                if (ifa->ifa_scope > scope)
 835                        continue;
 836                if (!daddr) {
 837                        saddr = ifa->ifa_local;
 838                        break;
 839                }
 840                ret = dn_match_addr(daddr, ifa->ifa_local);
 841                if (ret > best_match)
 842                        saddr = ifa->ifa_local;
 843                if (best_match == 0)
 844                        saddr = ifa->ifa_local;
 845        }
 846        read_unlock(&dev_base_lock);
 847
 848        return saddr;
 849}
 850
 851static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 852{
 853        return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 854}
 855
 856static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 857{
 858        __le16 mask = dnet_make_mask(res->prefixlen);
 859        return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 860}
 861
 862static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
 863{
 864        struct flowi fl = { .nl_u = { .dn_u =
 865                                      { .daddr = oldflp->fld_dst,
 866                                        .saddr = oldflp->fld_src,
 867                                        .scope = RT_SCOPE_UNIVERSE,
 868                                     } },
 869                            .mark = oldflp->mark,
 870                            .iif = init_net.loopback_dev->ifindex,
 871                            .oif = oldflp->oif };
 872        struct dn_route *rt = NULL;
 873        struct net_device *dev_out = NULL, *dev;
 874        struct neighbour *neigh = NULL;
 875        unsigned hash;
 876        unsigned flags = 0;
 877        struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 878        int err;
 879        int free_res = 0;
 880        __le16 gateway = 0;
 881
 882        if (decnet_debug_level & 16)
 883                printk(KERN_DEBUG
 884                       "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 885                       " iif=%d oif=%d\n", le16_to_cpu(oldflp->fld_dst),
 886                       le16_to_cpu(oldflp->fld_src),
 887                       oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);
 888
 889        /* If we have an output interface, verify its a DECnet device */
 890        if (oldflp->oif) {
 891                dev_out = dev_get_by_index(&init_net, oldflp->oif);
 892                err = -ENODEV;
 893                if (dev_out && dev_out->dn_ptr == NULL) {
 894                        dev_put(dev_out);
 895                        dev_out = NULL;
 896                }
 897                if (dev_out == NULL)
 898                        goto out;
 899        }
 900
 901        /* If we have a source address, verify that its a local address */
 902        if (oldflp->fld_src) {
 903                err = -EADDRNOTAVAIL;
 904
 905                if (dev_out) {
 906                        if (dn_dev_islocal(dev_out, oldflp->fld_src))
 907                                goto source_ok;
 908                        dev_put(dev_out);
 909                        goto out;
 910                }
 911                read_lock(&dev_base_lock);
 912                for_each_netdev(&init_net, dev) {
 913                        if (!dev->dn_ptr)
 914                                continue;
 915                        if (!dn_dev_islocal(dev, oldflp->fld_src))
 916                                continue;
 917                        if ((dev->flags & IFF_LOOPBACK) &&
 918                            oldflp->fld_dst &&
 919                            !dn_dev_islocal(dev, oldflp->fld_dst))
 920                                continue;
 921
 922                        dev_out = dev;
 923                        break;
 924                }
 925                read_unlock(&dev_base_lock);
 926                if (dev_out == NULL)
 927                        goto out;
 928                dev_hold(dev_out);
 929source_ok:
 930                ;
 931        }
 932
 933        /* No destination? Assume its local */
 934        if (!fl.fld_dst) {
 935                fl.fld_dst = fl.fld_src;
 936
 937                err = -EADDRNOTAVAIL;
 938                if (dev_out)
 939                        dev_put(dev_out);
 940                dev_out = init_net.loopback_dev;
 941                dev_hold(dev_out);
 942                if (!fl.fld_dst) {
 943                        fl.fld_dst =
 944                        fl.fld_src = dnet_select_source(dev_out, 0,
 945                                                       RT_SCOPE_HOST);
 946                        if (!fl.fld_dst)
 947                                goto out;
 948                }
 949                fl.oif = init_net.loopback_dev->ifindex;
 950                res.type = RTN_LOCAL;
 951                goto make_route;
 952        }
 953
 954        if (decnet_debug_level & 16)
 955                printk(KERN_DEBUG
 956                       "dn_route_output_slow: initial checks complete."
 957                       " dst=%o4x src=%04x oif=%d try_hard=%d\n",
 958                       le16_to_cpu(fl.fld_dst), le16_to_cpu(fl.fld_src),
 959                       fl.oif, try_hard);
 960
 961        /*
 962         * N.B. If the kernel is compiled without router support then
 963         * dn_fib_lookup() will evaluate to non-zero so this if () block
 964         * will always be executed.
 965         */
 966        err = -ESRCH;
 967        if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
 968                struct dn_dev *dn_db;
 969                if (err != -ESRCH)
 970                        goto out;
 971                /*
 972                 * Here the fallback is basically the standard algorithm for
 973                 * routing in endnodes which is described in the DECnet routing
 974                 * docs
 975                 *
 976                 * If we are not trying hard, look in neighbour cache.
 977                 * The result is tested to ensure that if a specific output
 978                 * device/source address was requested, then we honour that
 979                 * here
 980                 */
 981                if (!try_hard) {
 982                        neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fl.fld_dst);
 983                        if (neigh) {
 984                                if ((oldflp->oif &&
 985                                    (neigh->dev->ifindex != oldflp->oif)) ||
 986                                    (oldflp->fld_src &&
 987                                    (!dn_dev_islocal(neigh->dev,
 988                                                      oldflp->fld_src)))) {
 989                                        neigh_release(neigh);
 990                                        neigh = NULL;
 991                                } else {
 992                                        if (dev_out)
 993                                                dev_put(dev_out);
 994                                        if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
 995                                                dev_out = init_net.loopback_dev;
 996                                                res.type = RTN_LOCAL;
 997                                        } else {
 998                                                dev_out = neigh->dev;
 999                                        }
1000                                        dev_hold(dev_out);
1001                                        goto select_source;
1002                                }
1003                        }
1004                }
1005
1006                /* Not there? Perhaps its a local address */
1007                if (dev_out == NULL)
1008                        dev_out = dn_dev_get_default();
1009                err = -ENODEV;
1010                if (dev_out == NULL)
1011                        goto out;
1012                dn_db = dev_out->dn_ptr;
1013                /* Possible improvement - check all devices for local addr */
1014                if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1015                        dev_put(dev_out);
1016                        dev_out = init_net.loopback_dev;
1017                        dev_hold(dev_out);
1018                        res.type = RTN_LOCAL;
1019                        goto select_source;
1020                }
1021                /* Not local either.... try sending it to the default router */
1022                neigh = neigh_clone(dn_db->router);
1023                BUG_ON(neigh && neigh->dev != dev_out);
1024
1025                /* Ok then, we assume its directly connected and move on */
1026select_source:
1027                if (neigh)
1028                        gateway = ((struct dn_neigh *)neigh)->addr;
1029                if (gateway == 0)
1030                        gateway = fl.fld_dst;
1031                if (fl.fld_src == 0) {
1032                        fl.fld_src = dnet_select_source(dev_out, gateway,
1033                                                         res.type == RTN_LOCAL ?
1034                                                         RT_SCOPE_HOST :
1035                                                         RT_SCOPE_LINK);
1036                        if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1037                                goto e_addr;
1038                }
1039                fl.oif = dev_out->ifindex;
1040                goto make_route;
1041        }
1042        free_res = 1;
1043
1044        if (res.type == RTN_NAT)
1045                goto e_inval;
1046
1047        if (res.type == RTN_LOCAL) {
1048                if (!fl.fld_src)
1049                        fl.fld_src = fl.fld_dst;
1050                if (dev_out)
1051                        dev_put(dev_out);
1052                dev_out = init_net.loopback_dev;
1053                dev_hold(dev_out);
1054                fl.oif = dev_out->ifindex;
1055                if (res.fi)
1056                        dn_fib_info_put(res.fi);
1057                res.fi = NULL;
1058                goto make_route;
1059        }
1060
1061        if (res.fi->fib_nhs > 1 && fl.oif == 0)
1062                dn_fib_select_multipath(&fl, &res);
1063
1064        /*
1065         * We could add some logic to deal with default routes here and
1066         * get rid of some of the special casing above.
1067         */
1068
1069        if (!fl.fld_src)
1070                fl.fld_src = DN_FIB_RES_PREFSRC(res);
1071
1072        if (dev_out)
1073                dev_put(dev_out);
1074        dev_out = DN_FIB_RES_DEV(res);
1075        dev_hold(dev_out);
1076        fl.oif = dev_out->ifindex;
1077        gateway = DN_FIB_RES_GW(res);
1078
1079make_route:
1080        if (dev_out->flags & IFF_LOOPBACK)
1081                flags |= RTCF_LOCAL;
1082
1083        rt = dst_alloc(&dn_dst_ops);
1084        if (rt == NULL)
1085                goto e_nobufs;
1086
1087        atomic_set(&rt->u.dst.__refcnt, 1);
1088        rt->u.dst.flags   = DST_HOST;
1089
1090        rt->fl.fld_src    = oldflp->fld_src;
1091        rt->fl.fld_dst    = oldflp->fld_dst;
1092        rt->fl.oif        = oldflp->oif;
1093        rt->fl.iif        = 0;
1094        rt->fl.mark       = oldflp->mark;
1095
1096        rt->rt_saddr      = fl.fld_src;
1097        rt->rt_daddr      = fl.fld_dst;
1098        rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1099        rt->rt_local_src  = fl.fld_src;
1100
1101        rt->rt_dst_map    = fl.fld_dst;
1102        rt->rt_src_map    = fl.fld_src;
1103
1104        rt->u.dst.dev = dev_out;
1105        dev_hold(dev_out);
1106        rt->u.dst.neighbour = neigh;
1107        neigh = NULL;
1108
1109        rt->u.dst.lastuse = jiffies;
1110        rt->u.dst.output  = dn_output;
1111        rt->u.dst.input   = dn_rt_bug;
1112        rt->rt_flags      = flags;
1113        if (flags & RTCF_LOCAL)
1114                rt->u.dst.input = dn_nsp_rx;
1115
1116        err = dn_rt_set_next_hop(rt, &res);
1117        if (err)
1118                goto e_neighbour;
1119
1120        hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1121        dn_insert_route(rt, hash, (struct dn_route **)pprt);
1122
1123done:
1124        if (neigh)
1125                neigh_release(neigh);
1126        if (free_res)
1127                dn_fib_res_put(&res);
1128        if (dev_out)
1129                dev_put(dev_out);
1130out:
1131        return err;
1132
1133e_addr:
1134        err = -EADDRNOTAVAIL;
1135        goto done;
1136e_inval:
1137        err = -EINVAL;
1138        goto done;
1139e_nobufs:
1140        err = -ENOBUFS;
1141        goto done;
1142e_neighbour:
1143        dst_free(&rt->u.dst);
1144        goto e_nobufs;
1145}
1146
1147
1148/*
1149 * N.B. The flags may be moved into the flowi at some future stage.
1150 */
1151static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1152{
1153        unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1154        struct dn_route *rt = NULL;
1155
1156        if (!(flags & MSG_TRYHARD)) {
1157                rcu_read_lock_bh();
1158                for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt;
1159                        rt = rcu_dereference(rt->u.dst.dn_next)) {
1160                        if ((flp->fld_dst == rt->fl.fld_dst) &&
1161                            (flp->fld_src == rt->fl.fld_src) &&
1162                            (flp->mark == rt->fl.mark) &&
1163                            (rt->fl.iif == 0) &&
1164                            (rt->fl.oif == flp->oif)) {
1165                                dst_use(&rt->u.dst, jiffies);
1166                                rcu_read_unlock_bh();
1167                                *pprt = &rt->u.dst;
1168                                return 0;
1169                        }
1170                }
1171                rcu_read_unlock_bh();
1172        }
1173
1174        return dn_route_output_slow(pprt, flp, flags);
1175}
1176
1177static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
1178{
1179        int err;
1180
1181        err = __dn_route_output_key(pprt, flp, flags);
1182        if (err == 0 && flp->proto) {
1183                err = xfrm_lookup(&init_net, pprt, flp, NULL, 0);
1184        }
1185        return err;
1186}
1187
1188int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
1189{
1190        int err;
1191
1192        err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1193        if (err == 0 && fl->proto) {
1194                err = xfrm_lookup(&init_net, pprt, fl, sk,
1195                                 (flags & MSG_DONTWAIT) ? 0 : XFRM_LOOKUP_WAIT);
1196        }
1197        return err;
1198}
1199
1200static int dn_route_input_slow(struct sk_buff *skb)
1201{
1202        struct dn_route *rt = NULL;
1203        struct dn_skb_cb *cb = DN_SKB_CB(skb);
1204        struct net_device *in_dev = skb->dev;
1205        struct net_device *out_dev = NULL;
1206        struct dn_dev *dn_db;
1207        struct neighbour *neigh = NULL;
1208        unsigned hash;
1209        int flags = 0;
1210        __le16 gateway = 0;
1211        __le16 local_src = 0;
1212        struct flowi fl = { .nl_u = { .dn_u =
1213                                     { .daddr = cb->dst,
1214                                       .saddr = cb->src,
1215                                       .scope = RT_SCOPE_UNIVERSE,
1216                                    } },
1217                            .mark = skb->mark,
1218                            .iif = skb->dev->ifindex };
1219        struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1220        int err = -EINVAL;
1221        int free_res = 0;
1222
1223        dev_hold(in_dev);
1224
1225        if ((dn_db = in_dev->dn_ptr) == NULL)
1226                goto out;
1227
1228        /* Zero source addresses are not allowed */
1229        if (fl.fld_src == 0)
1230                goto out;
1231
1232        /*
1233         * In this case we've just received a packet from a source
1234         * outside ourselves pretending to come from us. We don't
1235         * allow it any further to prevent routing loops, spoofing and
1236         * other nasties. Loopback packets already have the dst attached
1237         * so this only affects packets which have originated elsewhere.
1238         */
1239        err  = -ENOTUNIQ;
1240        if (dn_dev_islocal(in_dev, cb->src))
1241                goto out;
1242
1243        err = dn_fib_lookup(&fl, &res);
1244        if (err) {
1245                if (err != -ESRCH)
1246                        goto out;
1247                /*
1248                 * Is the destination us ?
1249                 */
1250                if (!dn_dev_islocal(in_dev, cb->dst))
1251                        goto e_inval;
1252
1253                res.type = RTN_LOCAL;
1254        } else {
1255                __le16 src_map = fl.fld_src;
1256                free_res = 1;
1257
1258                out_dev = DN_FIB_RES_DEV(res);
1259                if (out_dev == NULL) {
1260                        if (net_ratelimit())
1261                                printk(KERN_CRIT "Bug in dn_route_input_slow() "
1262                                                 "No output device\n");
1263                        goto e_inval;
1264                }
1265                dev_hold(out_dev);
1266
1267                if (res.r)
1268                        src_map = fl.fld_src; /* no NAT support for now */
1269
1270                gateway = DN_FIB_RES_GW(res);
1271                if (res.type == RTN_NAT) {
1272                        fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1273                        dn_fib_res_put(&res);
1274                        free_res = 0;
1275                        if (dn_fib_lookup(&fl, &res))
1276                                goto e_inval;
1277                        free_res = 1;
1278                        if (res.type != RTN_UNICAST)
1279                                goto e_inval;
1280                        flags |= RTCF_DNAT;
1281                        gateway = fl.fld_dst;
1282                }
1283                fl.fld_src = src_map;
1284        }
1285
1286        switch(res.type) {
1287        case RTN_UNICAST:
1288                /*
1289                 * Forwarding check here, we only check for forwarding
1290                 * being turned off, if you want to only forward intra
1291                 * area, its up to you to set the routing tables up
1292                 * correctly.
1293                 */
1294                if (dn_db->parms.forwarding == 0)
1295                        goto e_inval;
1296
1297                if (res.fi->fib_nhs > 1 && fl.oif == 0)
1298                        dn_fib_select_multipath(&fl, &res);
1299
1300                /*
1301                 * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1302                 * flag as a hint to set the intra-ethernet bit when
1303                 * forwarding. If we've got NAT in operation, we don't do
1304                 * this optimisation.
1305                 */
1306                if (out_dev == in_dev && !(flags & RTCF_NAT))
1307                        flags |= RTCF_DOREDIRECT;
1308
1309                local_src = DN_FIB_RES_PREFSRC(res);
1310
1311        case RTN_BLACKHOLE:
1312        case RTN_UNREACHABLE:
1313                break;
1314        case RTN_LOCAL:
1315                flags |= RTCF_LOCAL;
1316                fl.fld_src = cb->dst;
1317                fl.fld_dst = cb->src;
1318
1319                /* Routing tables gave us a gateway */
1320                if (gateway)
1321                        goto make_route;
1322
1323                /* Packet was intra-ethernet, so we know its on-link */
1324                if (cb->rt_flags & DN_RT_F_IE) {
1325                        gateway = cb->src;
1326                        flags |= RTCF_DIRECTSRC;
1327                        goto make_route;
1328                }
1329
1330                /* Use the default router if there is one */
1331                neigh = neigh_clone(dn_db->router);
1332                if (neigh) {
1333                        gateway = ((struct dn_neigh *)neigh)->addr;
1334                        goto make_route;
1335                }
1336
1337                /* Close eyes and pray */
1338                gateway = cb->src;
1339                flags |= RTCF_DIRECTSRC;
1340                goto make_route;
1341        default:
1342                goto e_inval;
1343        }
1344
1345make_route:
1346        rt = dst_alloc(&dn_dst_ops);
1347        if (rt == NULL)
1348                goto e_nobufs;
1349
1350        rt->rt_saddr      = fl.fld_src;
1351        rt->rt_daddr      = fl.fld_dst;
1352        rt->rt_gateway    = fl.fld_dst;
1353        if (gateway)
1354                rt->rt_gateway = gateway;
1355        rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1356
1357        rt->rt_dst_map    = fl.fld_dst;
1358        rt->rt_src_map    = fl.fld_src;
1359
1360        rt->fl.fld_src    = cb->src;
1361        rt->fl.fld_dst    = cb->dst;
1362        rt->fl.oif        = 0;
1363        rt->fl.iif        = in_dev->ifindex;
1364        rt->fl.mark       = fl.mark;
1365
1366        rt->u.dst.flags = DST_HOST;
1367        rt->u.dst.neighbour = neigh;
1368        rt->u.dst.dev = out_dev;
1369        rt->u.dst.lastuse = jiffies;
1370        rt->u.dst.output = dn_rt_bug;
1371        switch(res.type) {
1372                case RTN_UNICAST:
1373                        rt->u.dst.input = dn_forward;
1374                        break;
1375                case RTN_LOCAL:
1376                        rt->u.dst.output = dn_output;
1377                        rt->u.dst.input = dn_nsp_rx;
1378                        rt->u.dst.dev = in_dev;
1379                        flags |= RTCF_LOCAL;
1380                        break;
1381                default:
1382                case RTN_UNREACHABLE:
1383                case RTN_BLACKHOLE:
1384                        rt->u.dst.input = dst_discard;
1385        }
1386        rt->rt_flags = flags;
1387        if (rt->u.dst.dev)
1388                dev_hold(rt->u.dst.dev);
1389
1390        err = dn_rt_set_next_hop(rt, &res);
1391        if (err)
1392                goto e_neighbour;
1393
1394        hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1395        dn_insert_route(rt, hash, (struct dn_route **)&skb->dst);
1396
1397done:
1398        if (neigh)
1399                neigh_release(neigh);
1400        if (free_res)
1401                dn_fib_res_put(&res);
1402        dev_put(in_dev);
1403        if (out_dev)
1404                dev_put(out_dev);
1405out:
1406        return err;
1407
1408e_inval:
1409        err = -EINVAL;
1410        goto done;
1411
1412e_nobufs:
1413        err = -ENOBUFS;
1414        goto done;
1415
1416e_neighbour:
1417        dst_free(&rt->u.dst);
1418        goto done;
1419}
1420
1421static int dn_route_input(struct sk_buff *skb)
1422{
1423        struct dn_route *rt;
1424        struct dn_skb_cb *cb = DN_SKB_CB(skb);
1425        unsigned hash = dn_hash(cb->src, cb->dst);
1426
1427        if (skb->dst)
1428                return 0;
1429
1430        rcu_read_lock();
1431        for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1432            rt = rcu_dereference(rt->u.dst.dn_next)) {
1433                if ((rt->fl.fld_src == cb->src) &&
1434                    (rt->fl.fld_dst == cb->dst) &&
1435                    (rt->fl.oif == 0) &&
1436                    (rt->fl.mark == skb->mark) &&
1437                    (rt->fl.iif == cb->iif)) {
1438                        dst_use(&rt->u.dst, jiffies);
1439                        rcu_read_unlock();
1440                        skb->dst = (struct dst_entry *)rt;
1441                        return 0;
1442                }
1443        }
1444        rcu_read_unlock();
1445
1446        return dn_route_input_slow(skb);
1447}
1448
1449static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1450                           int event, int nowait, unsigned int flags)
1451{
1452        struct dn_route *rt = (struct dn_route *)skb->dst;
1453        struct rtmsg *r;
1454        struct nlmsghdr *nlh;
1455        unsigned char *b = skb_tail_pointer(skb);
1456        long expires;
1457
1458        nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1459        r = NLMSG_DATA(nlh);
1460        r->rtm_family = AF_DECnet;
1461        r->rtm_dst_len = 16;
1462        r->rtm_src_len = 0;
1463        r->rtm_tos = 0;
1464        r->rtm_table = RT_TABLE_MAIN;
1465        RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
1466        r->rtm_type = rt->rt_type;
1467        r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1468        r->rtm_scope = RT_SCOPE_UNIVERSE;
1469        r->rtm_protocol = RTPROT_UNSPEC;
1470        if (rt->rt_flags & RTCF_NOTIFY)
1471                r->rtm_flags |= RTM_F_NOTIFY;
1472        RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1473        if (rt->fl.fld_src) {
1474                r->rtm_src_len = 16;
1475                RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1476        }
1477        if (rt->u.dst.dev)
1478                RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
1479        /*
1480         * Note to self - change this if input routes reverse direction when
1481         * they deal only with inputs and not with replies like they do
1482         * currently.
1483         */
1484        RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1485        if (rt->rt_daddr != rt->rt_gateway)
1486                RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1487        if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
1488                goto rtattr_failure;
1489        expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
1490        if (rtnl_put_cacheinfo(skb, &rt->u.dst, 0, 0, 0, expires,
1491                               rt->u.dst.error) < 0)
1492                goto rtattr_failure;
1493        if (rt->fl.iif)
1494                RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1495
1496        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1497        return skb->len;
1498
1499nlmsg_failure:
1500rtattr_failure:
1501        nlmsg_trim(skb, b);
1502        return -1;
1503}
1504
1505/*
1506 * This is called by both endnodes and routers now.
1507 */
1508static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1509{
1510        struct net *net = sock_net(in_skb->sk);
1511        struct rtattr **rta = arg;
1512        struct rtmsg *rtm = NLMSG_DATA(nlh);
1513        struct dn_route *rt = NULL;
1514        struct dn_skb_cb *cb;
1515        int err;
1516        struct sk_buff *skb;
1517        struct flowi fl;
1518
1519        if (net != &init_net)
1520                return -EINVAL;
1521
1522        memset(&fl, 0, sizeof(fl));
1523        fl.proto = DNPROTO_NSP;
1524
1525        skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1526        if (skb == NULL)
1527                return -ENOBUFS;
1528        skb_reset_mac_header(skb);
1529        cb = DN_SKB_CB(skb);
1530
1531        if (rta[RTA_SRC-1])
1532                memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1533        if (rta[RTA_DST-1])
1534                memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1535        if (rta[RTA_IIF-1])
1536                memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1537
1538        if (fl.iif) {
1539                struct net_device *dev;
1540                if ((dev = dev_get_by_index(&init_net, fl.iif)) == NULL) {
1541                        kfree_skb(skb);
1542                        return -ENODEV;
1543                }
1544                if (!dev->dn_ptr) {
1545                        dev_put(dev);
1546                        kfree_skb(skb);
1547                        return -ENODEV;
1548                }
1549                skb->protocol = htons(ETH_P_DNA_RT);
1550                skb->dev = dev;
1551                cb->src = fl.fld_src;
1552                cb->dst = fl.fld_dst;
1553                local_bh_disable();
1554                err = dn_route_input(skb);
1555                local_bh_enable();
1556                memset(cb, 0, sizeof(struct dn_skb_cb));
1557                rt = (struct dn_route *)skb->dst;
1558                if (!err && -rt->u.dst.error)
1559                        err = rt->u.dst.error;
1560        } else {
1561                int oif = 0;
1562                if (rta[RTA_OIF - 1])
1563                        memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1564                fl.oif = oif;
1565                err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1566        }
1567
1568        if (skb->dev)
1569                dev_put(skb->dev);
1570        skb->dev = NULL;
1571        if (err)
1572                goto out_free;
1573        skb->dst = &rt->u.dst;
1574        if (rtm->rtm_flags & RTM_F_NOTIFY)
1575                rt->rt_flags |= RTCF_NOTIFY;
1576
1577        err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1578
1579        if (err == 0)
1580                goto out_free;
1581        if (err < 0) {
1582                err = -EMSGSIZE;
1583                goto out_free;
1584        }
1585
1586        return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
1587
1588out_free:
1589        kfree_skb(skb);
1590        return err;
1591}
1592
1593/*
1594 * For routers, this is called from dn_fib_dump, but for endnodes its
1595 * called directly from the rtnetlink dispatch table.
1596 */
1597int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1598{
1599        struct net *net = sock_net(skb->sk);
1600        struct dn_route *rt;
1601        int h, s_h;
1602        int idx, s_idx;
1603
1604        if (net != &init_net)
1605                return 0;
1606
1607        if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1608                return -EINVAL;
1609        if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1610                return 0;
1611
1612        s_h = cb->args[0];
1613        s_idx = idx = cb->args[1];
1614        for(h = 0; h <= dn_rt_hash_mask; h++) {
1615                if (h < s_h)
1616                        continue;
1617                if (h > s_h)
1618                        s_idx = 0;
1619                rcu_read_lock_bh();
1620                for(rt = rcu_dereference(dn_rt_hash_table[h].chain), idx = 0;
1621                        rt;
1622                        rt = rcu_dereference(rt->u.dst.dn_next), idx++) {
1623                        if (idx < s_idx)
1624                                continue;
1625                        skb->dst = dst_clone(&rt->u.dst);
1626                        if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1627                                        cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1628                                        1, NLM_F_MULTI) <= 0) {
1629                                dst_release(xchg(&skb->dst, NULL));
1630                                rcu_read_unlock_bh();
1631                                goto done;
1632                        }
1633                        dst_release(xchg(&skb->dst, NULL));
1634                }
1635                rcu_read_unlock_bh();
1636        }
1637
1638done:
1639        cb->args[0] = h;
1640        cb->args[1] = idx;
1641        return skb->len;
1642}
1643
1644#ifdef CONFIG_PROC_FS
1645struct dn_rt_cache_iter_state {
1646        int bucket;
1647};
1648
1649static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1650{
1651        struct dn_route *rt = NULL;
1652        struct dn_rt_cache_iter_state *s = seq->private;
1653
1654        for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1655                rcu_read_lock_bh();
1656                rt = dn_rt_hash_table[s->bucket].chain;
1657                if (rt)
1658                        break;
1659                rcu_read_unlock_bh();
1660        }
1661        return rcu_dereference(rt);
1662}
1663
1664static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1665{
1666        struct dn_rt_cache_iter_state *s = seq->private;
1667
1668        rt = rt->u.dst.dn_next;
1669        while(!rt) {
1670                rcu_read_unlock_bh();
1671                if (--s->bucket < 0)
1672                        break;
1673                rcu_read_lock_bh();
1674                rt = dn_rt_hash_table[s->bucket].chain;
1675        }
1676        return rcu_dereference(rt);
1677}
1678
1679static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1680{
1681        struct dn_route *rt = dn_rt_cache_get_first(seq);
1682
1683        if (rt) {
1684                while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1685                        --*pos;
1686        }
1687        return *pos ? NULL : rt;
1688}
1689
1690static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1691{
1692        struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1693        ++*pos;
1694        return rt;
1695}
1696
1697static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1698{
1699        if (v)
1700                rcu_read_unlock_bh();
1701}
1702
1703static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1704{
1705        struct dn_route *rt = v;
1706        char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1707
1708        seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1709                        rt->u.dst.dev ? rt->u.dst.dev->name : "*",
1710                        dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1711                        dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1712                        atomic_read(&rt->u.dst.__refcnt),
1713                        rt->u.dst.__use,
1714                        (int) dst_metric(&rt->u.dst, RTAX_RTT));
1715        return 0;
1716}
1717
1718static const struct seq_operations dn_rt_cache_seq_ops = {
1719        .start  = dn_rt_cache_seq_start,
1720        .next   = dn_rt_cache_seq_next,
1721        .stop   = dn_rt_cache_seq_stop,
1722        .show   = dn_rt_cache_seq_show,
1723};
1724
1725static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1726{
1727        return seq_open_private(file, &dn_rt_cache_seq_ops,
1728                        sizeof(struct dn_rt_cache_iter_state));
1729}
1730
1731static const struct file_operations dn_rt_cache_seq_fops = {
1732        .owner   = THIS_MODULE,
1733        .open    = dn_rt_cache_seq_open,
1734        .read    = seq_read,
1735        .llseek  = seq_lseek,
1736        .release = seq_release_private,
1737};
1738
1739#endif /* CONFIG_PROC_FS */
1740
1741void __init dn_route_init(void)
1742{
1743        int i, goal, order;
1744
1745        dn_dst_ops.kmem_cachep =
1746                kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1747                                  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1748        setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1749        dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1750        add_timer(&dn_route_timer);
1751
1752        goal = num_physpages >> (26 - PAGE_SHIFT);
1753
1754        for(order = 0; (1UL << order) < goal; order++)
1755                /* NOTHING */;
1756
1757        /*
1758         * Only want 1024 entries max, since the table is very, very unlikely
1759         * to be larger than that.
1760         */
1761        while(order && ((((1UL << order) * PAGE_SIZE) /
1762                                sizeof(struct dn_rt_hash_bucket)) >= 2048))
1763                order--;
1764
1765        do {
1766                dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1767                        sizeof(struct dn_rt_hash_bucket);
1768                while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1769                        dn_rt_hash_mask--;
1770                dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1771                        __get_free_pages(GFP_ATOMIC, order);
1772        } while (dn_rt_hash_table == NULL && --order > 0);
1773
1774        if (!dn_rt_hash_table)
1775                panic("Failed to allocate DECnet route cache hash table\n");
1776
1777        printk(KERN_INFO
1778                "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1779                dn_rt_hash_mask,
1780                (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1781
1782        dn_rt_hash_mask--;
1783        for(i = 0; i <= dn_rt_hash_mask; i++) {
1784                spin_lock_init(&dn_rt_hash_table[i].lock);
1785                dn_rt_hash_table[i].chain = NULL;
1786        }
1787
1788        dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1789
1790        proc_net_fops_create(&init_net, "decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1791
1792#ifdef CONFIG_DECNET_ROUTER
1793        rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute, dn_fib_dump);
1794#else
1795        rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1796                      dn_cache_dump);
1797#endif
1798}
1799
1800void __exit dn_route_cleanup(void)
1801{
1802        del_timer(&dn_route_timer);
1803        dn_run_flush(0);
1804
1805        proc_net_remove(&init_net, "decnet_cache");
1806}
1807
1808