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