linux/net/decnet/dn_neigh.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 Neighbour Functions (Adjacency Database and
   7 *                                                        On-Ethernet Cache)
   8 *
   9 * Author:      Steve Whitehouse <SteveW@ACM.org>
  10 *
  11 *
  12 * Changes:
  13 *     Steve Whitehouse     : Fixed router listing routine
  14 *     Steve Whitehouse     : Added error_report functions
  15 *     Steve Whitehouse     : Added default router detection
  16 *     Steve Whitehouse     : Hop counts in outgoing messages
  17 *     Steve Whitehouse     : Fixed src/dst in outgoing messages so
  18 *                            forwarding now stands a good chance of
  19 *                            working.
  20 *     Steve Whitehouse     : Fixed neighbour states (for now anyway).
  21 *     Steve Whitehouse     : Made error_report functions dummies. This
  22 *                            is not the right place to return skbs.
  23 *     Steve Whitehouse     : Convert to seq_file
  24 *
  25 */
  26
  27#include <linux/net.h>
  28#include <linux/module.h>
  29#include <linux/socket.h>
  30#include <linux/if_arp.h>
  31#include <linux/slab.h>
  32#include <linux/if_ether.h>
  33#include <linux/init.h>
  34#include <linux/proc_fs.h>
  35#include <linux/string.h>
  36#include <linux/netfilter_decnet.h>
  37#include <linux/spinlock.h>
  38#include <linux/seq_file.h>
  39#include <linux/rcupdate.h>
  40#include <linux/jhash.h>
  41#include <linux/atomic.h>
  42#include <net/net_namespace.h>
  43#include <net/neighbour.h>
  44#include <net/dst.h>
  45#include <net/flow.h>
  46#include <net/dn.h>
  47#include <net/dn_dev.h>
  48#include <net/dn_neigh.h>
  49#include <net/dn_route.h>
  50
  51static int dn_neigh_construct(struct neighbour *);
  52static void dn_long_error_report(struct neighbour *, struct sk_buff *);
  53static void dn_short_error_report(struct neighbour *, struct sk_buff *);
  54static int dn_long_output(struct neighbour *, struct sk_buff *);
  55static int dn_short_output(struct neighbour *, struct sk_buff *);
  56static int dn_phase3_output(struct neighbour *, struct sk_buff *);
  57
  58
  59/*
  60 * For talking to broadcast devices: Ethernet & PPP
  61 */
  62static const struct neigh_ops dn_long_ops = {
  63        .family =               AF_DECnet,
  64        .error_report =         dn_long_error_report,
  65        .output =               dn_long_output,
  66        .connected_output =     dn_long_output,
  67};
  68
  69/*
  70 * For talking to pointopoint and multidrop devices: DDCMP and X.25
  71 */
  72static const struct neigh_ops dn_short_ops = {
  73        .family =               AF_DECnet,
  74        .error_report =         dn_short_error_report,
  75        .output =               dn_short_output,
  76        .connected_output =     dn_short_output,
  77};
  78
  79/*
  80 * For talking to DECnet phase III nodes
  81 */
  82static const struct neigh_ops dn_phase3_ops = {
  83        .family =               AF_DECnet,
  84        .error_report =         dn_short_error_report, /* Can use short version here */
  85        .output =               dn_phase3_output,
  86        .connected_output =     dn_phase3_output,
  87};
  88
  89static u32 dn_neigh_hash(const void *pkey,
  90                         const struct net_device *dev,
  91                         __u32 *hash_rnd)
  92{
  93        return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
  94}
  95
  96struct neigh_table dn_neigh_table = {
  97        .family =                       PF_DECnet,
  98        .entry_size =                   NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
  99        .key_len =                      sizeof(__le16),
 100        .hash =                         dn_neigh_hash,
 101        .constructor =                  dn_neigh_construct,
 102        .id =                           "dn_neigh_cache",
 103        .parms ={
 104                .tbl =                  &dn_neigh_table,
 105                .reachable_time =       30 * HZ,
 106                .data = {
 107                        [NEIGH_VAR_MCAST_PROBES] = 0,
 108                        [NEIGH_VAR_UCAST_PROBES] = 0,
 109                        [NEIGH_VAR_APP_PROBES] = 0,
 110                        [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
 111                        [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
 112                        [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
 113                        [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
 114                        [NEIGH_VAR_QUEUE_LEN_BYTES] = 64*1024,
 115                        [NEIGH_VAR_PROXY_QLEN] = 0,
 116                        [NEIGH_VAR_ANYCAST_DELAY] = 0,
 117                        [NEIGH_VAR_PROXY_DELAY] = 0,
 118                        [NEIGH_VAR_LOCKTIME] = 1 * HZ,
 119                },
 120        },
 121        .gc_interval =                  30 * HZ,
 122        .gc_thresh1 =                   128,
 123        .gc_thresh2 =                   512,
 124        .gc_thresh3 =                   1024,
 125};
 126
 127static int dn_neigh_construct(struct neighbour *neigh)
 128{
 129        struct net_device *dev = neigh->dev;
 130        struct dn_neigh *dn = (struct dn_neigh *)neigh;
 131        struct dn_dev *dn_db;
 132        struct neigh_parms *parms;
 133
 134        rcu_read_lock();
 135        dn_db = rcu_dereference(dev->dn_ptr);
 136        if (dn_db == NULL) {
 137                rcu_read_unlock();
 138                return -EINVAL;
 139        }
 140
 141        parms = dn_db->neigh_parms;
 142        if (!parms) {
 143                rcu_read_unlock();
 144                return -EINVAL;
 145        }
 146
 147        __neigh_parms_put(neigh->parms);
 148        neigh->parms = neigh_parms_clone(parms);
 149
 150        if (dn_db->use_long)
 151                neigh->ops = &dn_long_ops;
 152        else
 153                neigh->ops = &dn_short_ops;
 154        rcu_read_unlock();
 155
 156        if (dn->flags & DN_NDFLAG_P3)
 157                neigh->ops = &dn_phase3_ops;
 158
 159        neigh->nud_state = NUD_NOARP;
 160        neigh->output = neigh->ops->connected_output;
 161
 162        if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 163                memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 164        else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 165                dn_dn2eth(neigh->ha, dn->addr);
 166        else {
 167                net_dbg_ratelimited("Trying to create neigh for hw %d\n",
 168                                    dev->type);
 169                return -EINVAL;
 170        }
 171
 172        /*
 173         * Make an estimate of the remote block size by assuming that its
 174         * two less then the device mtu, which it true for ethernet (and
 175         * other things which support long format headers) since there is
 176         * an extra length field (of 16 bits) which isn't part of the
 177         * ethernet headers and which the DECnet specs won't admit is part
 178         * of the DECnet routing headers either.
 179         *
 180         * If we over estimate here its no big deal, the NSP negotiations
 181         * will prevent us from sending packets which are too large for the
 182         * remote node to handle. In any case this figure is normally updated
 183         * by a hello message in most cases.
 184         */
 185        dn->blksize = dev->mtu - 2;
 186
 187        return 0;
 188}
 189
 190static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
 191{
 192        printk(KERN_DEBUG "dn_long_error_report: called\n");
 193        kfree_skb(skb);
 194}
 195
 196
 197static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
 198{
 199        printk(KERN_DEBUG "dn_short_error_report: called\n");
 200        kfree_skb(skb);
 201}
 202
 203static int dn_neigh_output_packet(struct sk_buff *skb)
 204{
 205        struct dst_entry *dst = skb_dst(skb);
 206        struct dn_route *rt = (struct dn_route *)dst;
 207        struct neighbour *neigh = rt->n;
 208        struct net_device *dev = neigh->dev;
 209        char mac_addr[ETH_ALEN];
 210        unsigned int seq;
 211        int err;
 212
 213        dn_dn2eth(mac_addr, rt->rt_local_src);
 214        do {
 215                seq = read_seqbegin(&neigh->ha_lock);
 216                err = dev_hard_header(skb, dev, ntohs(skb->protocol),
 217                                      neigh->ha, mac_addr, skb->len);
 218        } while (read_seqretry(&neigh->ha_lock, seq));
 219
 220        if (err >= 0)
 221                err = dev_queue_xmit(skb);
 222        else {
 223                kfree_skb(skb);
 224                err = -EINVAL;
 225        }
 226        return err;
 227}
 228
 229static int dn_long_output(struct neighbour *neigh, struct sk_buff *skb)
 230{
 231        struct net_device *dev = neigh->dev;
 232        int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
 233        unsigned char *data;
 234        struct dn_long_packet *lp;
 235        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 236
 237
 238        if (skb_headroom(skb) < headroom) {
 239                struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 240                if (skb2 == NULL) {
 241                        net_crit_ratelimited("dn_long_output: no memory\n");
 242                        kfree_skb(skb);
 243                        return -ENOBUFS;
 244                }
 245                consume_skb(skb);
 246                skb = skb2;
 247                net_info_ratelimited("dn_long_output: Increasing headroom\n");
 248        }
 249
 250        data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
 251        lp = (struct dn_long_packet *)(data+3);
 252
 253        *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 254        *(data + 2) = 1 | DN_RT_F_PF; /* Padding */
 255
 256        lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
 257        lp->d_area   = lp->d_subarea = 0;
 258        dn_dn2eth(lp->d_id, cb->dst);
 259        lp->s_area   = lp->s_subarea = 0;
 260        dn_dn2eth(lp->s_id, cb->src);
 261        lp->nl2      = 0;
 262        lp->visit_ct = cb->hops & 0x3f;
 263        lp->s_class  = 0;
 264        lp->pt       = 0;
 265
 266        skb_reset_network_header(skb);
 267
 268        return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 269                       neigh->dev, dn_neigh_output_packet);
 270}
 271
 272static int dn_short_output(struct neighbour *neigh, struct sk_buff *skb)
 273{
 274        struct net_device *dev = neigh->dev;
 275        int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 276        struct dn_short_packet *sp;
 277        unsigned char *data;
 278        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 279
 280
 281        if (skb_headroom(skb) < headroom) {
 282                struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 283                if (skb2 == NULL) {
 284                        net_crit_ratelimited("dn_short_output: no memory\n");
 285                        kfree_skb(skb);
 286                        return -ENOBUFS;
 287                }
 288                consume_skb(skb);
 289                skb = skb2;
 290                net_info_ratelimited("dn_short_output: Increasing headroom\n");
 291        }
 292
 293        data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 294        *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 295        sp = (struct dn_short_packet *)(data+2);
 296
 297        sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 298        sp->dstnode    = cb->dst;
 299        sp->srcnode    = cb->src;
 300        sp->forward    = cb->hops & 0x3f;
 301
 302        skb_reset_network_header(skb);
 303
 304        return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 305                       neigh->dev, dn_neigh_output_packet);
 306}
 307
 308/*
 309 * Phase 3 output is the same is short output, execpt that
 310 * it clears the area bits before transmission.
 311 */
 312static int dn_phase3_output(struct neighbour *neigh, struct sk_buff *skb)
 313{
 314        struct net_device *dev = neigh->dev;
 315        int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 316        struct dn_short_packet *sp;
 317        unsigned char *data;
 318        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 319
 320        if (skb_headroom(skb) < headroom) {
 321                struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 322                if (skb2 == NULL) {
 323                        net_crit_ratelimited("dn_phase3_output: no memory\n");
 324                        kfree_skb(skb);
 325                        return -ENOBUFS;
 326                }
 327                consume_skb(skb);
 328                skb = skb2;
 329                net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
 330        }
 331
 332        data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 333        *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 334        sp = (struct dn_short_packet *)(data + 2);
 335
 336        sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 337        sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
 338        sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
 339        sp->forward  = cb->hops & 0x3f;
 340
 341        skb_reset_network_header(skb);
 342
 343        return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
 344                       neigh->dev, dn_neigh_output_packet);
 345}
 346
 347/*
 348 * Unfortunately, the neighbour code uses the device in its hash
 349 * function, so we don't get any advantage from it. This function
 350 * basically does a neigh_lookup(), but without comparing the device
 351 * field. This is required for the On-Ethernet cache
 352 */
 353
 354/*
 355 * Pointopoint link receives a hello message
 356 */
 357void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 358{
 359        kfree_skb(skb);
 360}
 361
 362/*
 363 * Ethernet router hello message received
 364 */
 365int dn_neigh_router_hello(struct sk_buff *skb)
 366{
 367        struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 368
 369        struct neighbour *neigh;
 370        struct dn_neigh *dn;
 371        struct dn_dev *dn_db;
 372        __le16 src;
 373
 374        src = dn_eth2dn(msg->id);
 375
 376        neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 377
 378        dn = (struct dn_neigh *)neigh;
 379
 380        if (neigh) {
 381                write_lock(&neigh->lock);
 382
 383                neigh->used = jiffies;
 384                dn_db = rcu_dereference(neigh->dev->dn_ptr);
 385
 386                if (!(neigh->nud_state & NUD_PERMANENT)) {
 387                        neigh->updated = jiffies;
 388
 389                        if (neigh->dev->type == ARPHRD_ETHER)
 390                                memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 391
 392                        dn->blksize  = le16_to_cpu(msg->blksize);
 393                        dn->priority = msg->priority;
 394
 395                        dn->flags &= ~DN_NDFLAG_P3;
 396
 397                        switch (msg->iinfo & DN_RT_INFO_TYPE) {
 398                        case DN_RT_INFO_L1RT:
 399                                dn->flags &=~DN_NDFLAG_R2;
 400                                dn->flags |= DN_NDFLAG_R1;
 401                                break;
 402                        case DN_RT_INFO_L2RT:
 403                                dn->flags |= DN_NDFLAG_R2;
 404                        }
 405                }
 406
 407                /* Only use routers in our area */
 408                if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
 409                        if (!dn_db->router) {
 410                                dn_db->router = neigh_clone(neigh);
 411                        } else {
 412                                if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 413                                        neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 414                        }
 415                }
 416                write_unlock(&neigh->lock);
 417                neigh_release(neigh);
 418        }
 419
 420        kfree_skb(skb);
 421        return 0;
 422}
 423
 424/*
 425 * Endnode hello message received
 426 */
 427int dn_neigh_endnode_hello(struct sk_buff *skb)
 428{
 429        struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 430        struct neighbour *neigh;
 431        struct dn_neigh *dn;
 432        __le16 src;
 433
 434        src = dn_eth2dn(msg->id);
 435
 436        neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 437
 438        dn = (struct dn_neigh *)neigh;
 439
 440        if (neigh) {
 441                write_lock(&neigh->lock);
 442
 443                neigh->used = jiffies;
 444
 445                if (!(neigh->nud_state & NUD_PERMANENT)) {
 446                        neigh->updated = jiffies;
 447
 448                        if (neigh->dev->type == ARPHRD_ETHER)
 449                                memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 450                        dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 451                        dn->blksize  = le16_to_cpu(msg->blksize);
 452                        dn->priority = 0;
 453                }
 454
 455                write_unlock(&neigh->lock);
 456                neigh_release(neigh);
 457        }
 458
 459        kfree_skb(skb);
 460        return 0;
 461}
 462
 463static char *dn_find_slot(char *base, int max, int priority)
 464{
 465        int i;
 466        unsigned char *min = NULL;
 467
 468        base += 6; /* skip first id */
 469
 470        for(i = 0; i < max; i++) {
 471                if (!min || (*base < *min))
 472                        min = base;
 473                base += 7; /* find next priority */
 474        }
 475
 476        if (!min)
 477                return NULL;
 478
 479        return (*min < priority) ? (min - 6) : NULL;
 480}
 481
 482struct elist_cb_state {
 483        struct net_device *dev;
 484        unsigned char *ptr;
 485        unsigned char *rs;
 486        int t, n;
 487};
 488
 489static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 490{
 491        struct elist_cb_state *s = _info;
 492        struct dn_neigh *dn;
 493
 494        if (neigh->dev != s->dev)
 495                return;
 496
 497        dn = (struct dn_neigh *) neigh;
 498        if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 499                return;
 500
 501        if (s->t == s->n)
 502                s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 503        else
 504                s->t++;
 505        if (s->rs == NULL)
 506                return;
 507
 508        dn_dn2eth(s->rs, dn->addr);
 509        s->rs += 6;
 510        *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 511        *(s->rs) |= dn->priority;
 512        s->rs++;
 513}
 514
 515int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 516{
 517        struct elist_cb_state state;
 518
 519        state.dev = dev;
 520        state.t = 0;
 521        state.n = n;
 522        state.ptr = ptr;
 523        state.rs = ptr;
 524
 525        neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 526
 527        return state.t;
 528}
 529
 530
 531#ifdef CONFIG_PROC_FS
 532
 533static inline void dn_neigh_format_entry(struct seq_file *seq,
 534                                         struct neighbour *n)
 535{
 536        struct dn_neigh *dn = (struct dn_neigh *) n;
 537        char buf[DN_ASCBUF_LEN];
 538
 539        read_lock(&n->lock);
 540        seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 541                   dn_addr2asc(le16_to_cpu(dn->addr), buf),
 542                   (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 543                   (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 544                   (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 545                   dn->n.nud_state,
 546                   atomic_read(&dn->n.refcnt),
 547                   dn->blksize,
 548                   (dn->n.dev) ? dn->n.dev->name : "?");
 549        read_unlock(&n->lock);
 550}
 551
 552static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 553{
 554        if (v == SEQ_START_TOKEN) {
 555                seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 556        } else {
 557                dn_neigh_format_entry(seq, v);
 558        }
 559
 560        return 0;
 561}
 562
 563static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 564{
 565        return neigh_seq_start(seq, pos, &dn_neigh_table,
 566                               NEIGH_SEQ_NEIGH_ONLY);
 567}
 568
 569static const struct seq_operations dn_neigh_seq_ops = {
 570        .start = dn_neigh_seq_start,
 571        .next  = neigh_seq_next,
 572        .stop  = neigh_seq_stop,
 573        .show  = dn_neigh_seq_show,
 574};
 575
 576static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 577{
 578        return seq_open_net(inode, file, &dn_neigh_seq_ops,
 579                            sizeof(struct neigh_seq_state));
 580}
 581
 582static const struct file_operations dn_neigh_seq_fops = {
 583        .owner          = THIS_MODULE,
 584        .open           = dn_neigh_seq_open,
 585        .read           = seq_read,
 586        .llseek         = seq_lseek,
 587        .release        = seq_release_net,
 588};
 589
 590#endif
 591
 592void __init dn_neigh_init(void)
 593{
 594        neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
 595        proc_create("decnet_neigh", S_IRUGO, init_net.proc_net,
 596                    &dn_neigh_seq_fops);
 597}
 598
 599void __exit dn_neigh_cleanup(void)
 600{
 601        remove_proc_entry("decnet_neigh", init_net.proc_net);
 602        neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
 603}
 604