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_neigh_error_report(struct neighbour *, struct sk_buff *);
  53static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb);
  54
  55/*
  56 * Operations for adding the link layer header.
  57 */
  58static const struct neigh_ops dn_neigh_ops = {
  59        .family =               AF_DECnet,
  60        .error_report =         dn_neigh_error_report,
  61        .output =               dn_neigh_output,
  62        .connected_output =     dn_neigh_output,
  63};
  64
  65static u32 dn_neigh_hash(const void *pkey,
  66                         const struct net_device *dev,
  67                         __u32 *hash_rnd)
  68{
  69        return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
  70}
  71
  72static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)
  73{
  74        return neigh_key_eq16(neigh, pkey);
  75}
  76
  77struct neigh_table dn_neigh_table = {
  78        .family =                       PF_DECnet,
  79        .entry_size =                   NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
  80        .key_len =                      sizeof(__le16),
  81        .protocol =                     cpu_to_be16(ETH_P_DNA_RT),
  82        .hash =                         dn_neigh_hash,
  83        .key_eq =                       dn_key_eq,
  84        .constructor =                  dn_neigh_construct,
  85        .id =                           "dn_neigh_cache",
  86        .parms ={
  87                .tbl =                  &dn_neigh_table,
  88                .reachable_time =       30 * HZ,
  89                .data = {
  90                        [NEIGH_VAR_MCAST_PROBES] = 0,
  91                        [NEIGH_VAR_UCAST_PROBES] = 0,
  92                        [NEIGH_VAR_APP_PROBES] = 0,
  93                        [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
  94                        [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
  95                        [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
  96                        [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
  97                        [NEIGH_VAR_QUEUE_LEN_BYTES] = 64*1024,
  98                        [NEIGH_VAR_PROXY_QLEN] = 0,
  99                        [NEIGH_VAR_ANYCAST_DELAY] = 0,
 100                        [NEIGH_VAR_PROXY_DELAY] = 0,
 101                        [NEIGH_VAR_LOCKTIME] = 1 * HZ,
 102                },
 103        },
 104        .gc_interval =                  30 * HZ,
 105        .gc_thresh1 =                   128,
 106        .gc_thresh2 =                   512,
 107        .gc_thresh3 =                   1024,
 108};
 109
 110static int dn_neigh_construct(struct neighbour *neigh)
 111{
 112        struct net_device *dev = neigh->dev;
 113        struct dn_neigh *dn = (struct dn_neigh *)neigh;
 114        struct dn_dev *dn_db;
 115        struct neigh_parms *parms;
 116
 117        rcu_read_lock();
 118        dn_db = rcu_dereference(dev->dn_ptr);
 119        if (dn_db == NULL) {
 120                rcu_read_unlock();
 121                return -EINVAL;
 122        }
 123
 124        parms = dn_db->neigh_parms;
 125        if (!parms) {
 126                rcu_read_unlock();
 127                return -EINVAL;
 128        }
 129
 130        __neigh_parms_put(neigh->parms);
 131        neigh->parms = neigh_parms_clone(parms);
 132        rcu_read_unlock();
 133
 134        neigh->ops = &dn_neigh_ops;
 135        neigh->nud_state = NUD_NOARP;
 136        neigh->output = neigh->ops->connected_output;
 137
 138        if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 139                memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 140        else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 141                dn_dn2eth(neigh->ha, dn->addr);
 142        else {
 143                net_dbg_ratelimited("Trying to create neigh for hw %d\n",
 144                                    dev->type);
 145                return -EINVAL;
 146        }
 147
 148        /*
 149         * Make an estimate of the remote block size by assuming that its
 150         * two less then the device mtu, which it true for ethernet (and
 151         * other things which support long format headers) since there is
 152         * an extra length field (of 16 bits) which isn't part of the
 153         * ethernet headers and which the DECnet specs won't admit is part
 154         * of the DECnet routing headers either.
 155         *
 156         * If we over estimate here its no big deal, the NSP negotiations
 157         * will prevent us from sending packets which are too large for the
 158         * remote node to handle. In any case this figure is normally updated
 159         * by a hello message in most cases.
 160         */
 161        dn->blksize = dev->mtu - 2;
 162
 163        return 0;
 164}
 165
 166static void dn_neigh_error_report(struct neighbour *neigh, struct sk_buff *skb)
 167{
 168        printk(KERN_DEBUG "dn_neigh_error_report: called\n");
 169        kfree_skb(skb);
 170}
 171
 172static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb)
 173{
 174        struct dst_entry *dst = skb_dst(skb);
 175        struct dn_route *rt = (struct dn_route *)dst;
 176        struct net_device *dev = neigh->dev;
 177        char mac_addr[ETH_ALEN];
 178        unsigned int seq;
 179        int err;
 180
 181        dn_dn2eth(mac_addr, rt->rt_local_src);
 182        do {
 183                seq = read_seqbegin(&neigh->ha_lock);
 184                err = dev_hard_header(skb, dev, ntohs(skb->protocol),
 185                                      neigh->ha, mac_addr, skb->len);
 186        } while (read_seqretry(&neigh->ha_lock, seq));
 187
 188        if (err >= 0)
 189                err = dev_queue_xmit(skb);
 190        else {
 191                kfree_skb(skb);
 192                err = -EINVAL;
 193        }
 194        return err;
 195}
 196
 197static int dn_neigh_output_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
 198{
 199        struct dst_entry *dst = skb_dst(skb);
 200        struct dn_route *rt = (struct dn_route *)dst;
 201        struct neighbour *neigh = rt->n;
 202
 203        return neigh->output(neigh, skb);
 204}
 205
 206/*
 207 * For talking to broadcast devices: Ethernet & PPP
 208 */
 209static int dn_long_output(struct neighbour *neigh, struct sock *sk,
 210                          struct sk_buff *skb)
 211{
 212        struct net_device *dev = neigh->dev;
 213        int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
 214        unsigned char *data;
 215        struct dn_long_packet *lp;
 216        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 217
 218
 219        if (skb_headroom(skb) < headroom) {
 220                struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 221                if (skb2 == NULL) {
 222                        net_crit_ratelimited("dn_long_output: no memory\n");
 223                        kfree_skb(skb);
 224                        return -ENOBUFS;
 225                }
 226                consume_skb(skb);
 227                skb = skb2;
 228                net_info_ratelimited("dn_long_output: Increasing headroom\n");
 229        }
 230
 231        data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
 232        lp = (struct dn_long_packet *)(data+3);
 233
 234        *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 235        *(data + 2) = 1 | DN_RT_F_PF; /* Padding */
 236
 237        lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
 238        lp->d_area   = lp->d_subarea = 0;
 239        dn_dn2eth(lp->d_id, cb->dst);
 240        lp->s_area   = lp->s_subarea = 0;
 241        dn_dn2eth(lp->s_id, cb->src);
 242        lp->nl2      = 0;
 243        lp->visit_ct = cb->hops & 0x3f;
 244        lp->s_class  = 0;
 245        lp->pt       = 0;
 246
 247        skb_reset_network_header(skb);
 248
 249        return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
 250                       &init_net, sk, skb, NULL, neigh->dev,
 251                       dn_neigh_output_packet);
 252}
 253
 254/*
 255 * For talking to pointopoint and multidrop devices: DDCMP and X.25
 256 */
 257static int dn_short_output(struct neighbour *neigh, struct sock *sk,
 258                           struct sk_buff *skb)
 259{
 260        struct net_device *dev = neigh->dev;
 261        int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 262        struct dn_short_packet *sp;
 263        unsigned char *data;
 264        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 265
 266
 267        if (skb_headroom(skb) < headroom) {
 268                struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 269                if (skb2 == NULL) {
 270                        net_crit_ratelimited("dn_short_output: no memory\n");
 271                        kfree_skb(skb);
 272                        return -ENOBUFS;
 273                }
 274                consume_skb(skb);
 275                skb = skb2;
 276                net_info_ratelimited("dn_short_output: Increasing headroom\n");
 277        }
 278
 279        data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 280        *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 281        sp = (struct dn_short_packet *)(data+2);
 282
 283        sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 284        sp->dstnode    = cb->dst;
 285        sp->srcnode    = cb->src;
 286        sp->forward    = cb->hops & 0x3f;
 287
 288        skb_reset_network_header(skb);
 289
 290        return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
 291                       &init_net, sk, skb, NULL, neigh->dev,
 292                       dn_neigh_output_packet);
 293}
 294
 295/*
 296 * For talking to DECnet phase III nodes
 297 * Phase 3 output is the same as short output, execpt that
 298 * it clears the area bits before transmission.
 299 */
 300static int dn_phase3_output(struct neighbour *neigh, struct sock *sk,
 301                            struct sk_buff *skb)
 302{
 303        struct net_device *dev = neigh->dev;
 304        int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 305        struct dn_short_packet *sp;
 306        unsigned char *data;
 307        struct dn_skb_cb *cb = DN_SKB_CB(skb);
 308
 309        if (skb_headroom(skb) < headroom) {
 310                struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 311                if (skb2 == NULL) {
 312                        net_crit_ratelimited("dn_phase3_output: no memory\n");
 313                        kfree_skb(skb);
 314                        return -ENOBUFS;
 315                }
 316                consume_skb(skb);
 317                skb = skb2;
 318                net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
 319        }
 320
 321        data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 322        *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 323        sp = (struct dn_short_packet *)(data + 2);
 324
 325        sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 326        sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
 327        sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
 328        sp->forward  = cb->hops & 0x3f;
 329
 330        skb_reset_network_header(skb);
 331
 332        return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
 333                       &init_net, sk, skb, NULL, neigh->dev,
 334                       dn_neigh_output_packet);
 335}
 336
 337int dn_to_neigh_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 338{
 339        struct dst_entry *dst = skb_dst(skb);
 340        struct dn_route *rt = (struct dn_route *) dst;
 341        struct neighbour *neigh = rt->n;
 342        struct dn_neigh *dn = (struct dn_neigh *)neigh;
 343        struct dn_dev *dn_db;
 344        bool use_long;
 345
 346        rcu_read_lock();
 347        dn_db = rcu_dereference(neigh->dev->dn_ptr);
 348        if (dn_db == NULL) {
 349                rcu_read_unlock();
 350                return -EINVAL;
 351        }
 352        use_long = dn_db->use_long;
 353        rcu_read_unlock();
 354
 355        if (dn->flags & DN_NDFLAG_P3)
 356                return dn_phase3_output(neigh, sk, skb);
 357        if (use_long)
 358                return dn_long_output(neigh, sk, skb);
 359        else
 360                return dn_short_output(neigh, sk, skb);
 361}
 362
 363/*
 364 * Unfortunately, the neighbour code uses the device in its hash
 365 * function, so we don't get any advantage from it. This function
 366 * basically does a neigh_lookup(), but without comparing the device
 367 * field. This is required for the On-Ethernet cache
 368 */
 369
 370/*
 371 * Pointopoint link receives a hello message
 372 */
 373void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 374{
 375        kfree_skb(skb);
 376}
 377
 378/*
 379 * Ethernet router hello message received
 380 */
 381int dn_neigh_router_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
 382{
 383        struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 384
 385        struct neighbour *neigh;
 386        struct dn_neigh *dn;
 387        struct dn_dev *dn_db;
 388        __le16 src;
 389
 390        src = dn_eth2dn(msg->id);
 391
 392        neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 393
 394        dn = (struct dn_neigh *)neigh;
 395
 396        if (neigh) {
 397                write_lock(&neigh->lock);
 398
 399                neigh->used = jiffies;
 400                dn_db = rcu_dereference(neigh->dev->dn_ptr);
 401
 402                if (!(neigh->nud_state & NUD_PERMANENT)) {
 403                        neigh->updated = jiffies;
 404
 405                        if (neigh->dev->type == ARPHRD_ETHER)
 406                                memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 407
 408                        dn->blksize  = le16_to_cpu(msg->blksize);
 409                        dn->priority = msg->priority;
 410
 411                        dn->flags &= ~DN_NDFLAG_P3;
 412
 413                        switch (msg->iinfo & DN_RT_INFO_TYPE) {
 414                        case DN_RT_INFO_L1RT:
 415                                dn->flags &=~DN_NDFLAG_R2;
 416                                dn->flags |= DN_NDFLAG_R1;
 417                                break;
 418                        case DN_RT_INFO_L2RT:
 419                                dn->flags |= DN_NDFLAG_R2;
 420                        }
 421                }
 422
 423                /* Only use routers in our area */
 424                if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
 425                        if (!dn_db->router) {
 426                                dn_db->router = neigh_clone(neigh);
 427                        } else {
 428                                if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 429                                        neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 430                        }
 431                }
 432                write_unlock(&neigh->lock);
 433                neigh_release(neigh);
 434        }
 435
 436        kfree_skb(skb);
 437        return 0;
 438}
 439
 440/*
 441 * Endnode hello message received
 442 */
 443int dn_neigh_endnode_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
 444{
 445        struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 446        struct neighbour *neigh;
 447        struct dn_neigh *dn;
 448        __le16 src;
 449
 450        src = dn_eth2dn(msg->id);
 451
 452        neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 453
 454        dn = (struct dn_neigh *)neigh;
 455
 456        if (neigh) {
 457                write_lock(&neigh->lock);
 458
 459                neigh->used = jiffies;
 460
 461                if (!(neigh->nud_state & NUD_PERMANENT)) {
 462                        neigh->updated = jiffies;
 463
 464                        if (neigh->dev->type == ARPHRD_ETHER)
 465                                memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 466                        dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 467                        dn->blksize  = le16_to_cpu(msg->blksize);
 468                        dn->priority = 0;
 469                }
 470
 471                write_unlock(&neigh->lock);
 472                neigh_release(neigh);
 473        }
 474
 475        kfree_skb(skb);
 476        return 0;
 477}
 478
 479static char *dn_find_slot(char *base, int max, int priority)
 480{
 481        int i;
 482        unsigned char *min = NULL;
 483
 484        base += 6; /* skip first id */
 485
 486        for(i = 0; i < max; i++) {
 487                if (!min || (*base < *min))
 488                        min = base;
 489                base += 7; /* find next priority */
 490        }
 491
 492        if (!min)
 493                return NULL;
 494
 495        return (*min < priority) ? (min - 6) : NULL;
 496}
 497
 498struct elist_cb_state {
 499        struct net_device *dev;
 500        unsigned char *ptr;
 501        unsigned char *rs;
 502        int t, n;
 503};
 504
 505static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 506{
 507        struct elist_cb_state *s = _info;
 508        struct dn_neigh *dn;
 509
 510        if (neigh->dev != s->dev)
 511                return;
 512
 513        dn = (struct dn_neigh *) neigh;
 514        if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 515                return;
 516
 517        if (s->t == s->n)
 518                s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 519        else
 520                s->t++;
 521        if (s->rs == NULL)
 522                return;
 523
 524        dn_dn2eth(s->rs, dn->addr);
 525        s->rs += 6;
 526        *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 527        *(s->rs) |= dn->priority;
 528        s->rs++;
 529}
 530
 531int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 532{
 533        struct elist_cb_state state;
 534
 535        state.dev = dev;
 536        state.t = 0;
 537        state.n = n;
 538        state.ptr = ptr;
 539        state.rs = ptr;
 540
 541        neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 542
 543        return state.t;
 544}
 545
 546
 547#ifdef CONFIG_PROC_FS
 548
 549static inline void dn_neigh_format_entry(struct seq_file *seq,
 550                                         struct neighbour *n)
 551{
 552        struct dn_neigh *dn = (struct dn_neigh *) n;
 553        char buf[DN_ASCBUF_LEN];
 554
 555        read_lock(&n->lock);
 556        seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 557                   dn_addr2asc(le16_to_cpu(dn->addr), buf),
 558                   (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 559                   (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 560                   (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 561                   dn->n.nud_state,
 562                   atomic_read(&dn->n.refcnt),
 563                   dn->blksize,
 564                   (dn->n.dev) ? dn->n.dev->name : "?");
 565        read_unlock(&n->lock);
 566}
 567
 568static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 569{
 570        if (v == SEQ_START_TOKEN) {
 571                seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 572        } else {
 573                dn_neigh_format_entry(seq, v);
 574        }
 575
 576        return 0;
 577}
 578
 579static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 580{
 581        return neigh_seq_start(seq, pos, &dn_neigh_table,
 582                               NEIGH_SEQ_NEIGH_ONLY);
 583}
 584
 585static const struct seq_operations dn_neigh_seq_ops = {
 586        .start = dn_neigh_seq_start,
 587        .next  = neigh_seq_next,
 588        .stop  = neigh_seq_stop,
 589        .show  = dn_neigh_seq_show,
 590};
 591
 592static int dn_neigh_seq_open(struct inode *inode, struct file *file)
 593{
 594        return seq_open_net(inode, file, &dn_neigh_seq_ops,
 595                            sizeof(struct neigh_seq_state));
 596}
 597
 598static const struct file_operations dn_neigh_seq_fops = {
 599        .owner          = THIS_MODULE,
 600        .open           = dn_neigh_seq_open,
 601        .read           = seq_read,
 602        .llseek         = seq_lseek,
 603        .release        = seq_release_net,
 604};
 605
 606#endif
 607
 608void __init dn_neigh_init(void)
 609{
 610        neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
 611        proc_create("decnet_neigh", S_IRUGO, init_net.proc_net,
 612                    &dn_neigh_seq_fops);
 613}
 614
 615void __exit dn_neigh_cleanup(void)
 616{
 617        remove_proc_entry("decnet_neigh", init_net.proc_net);
 618        neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
 619}
 620