net/decnet/dn_neigh.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   4  *              operating system.  DECnet is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              DECnet Neighbour Functions (Adjacency Database and
   8  *                                                        On-Ethernet Cache)
   9  *
  10  * Author:      Steve Whitehouse <SteveW@ACM.org>
  11  *
  12  *
  13  * Changes:
  14  *     Steve Whitehouse     : Fixed router listing routine
  15  *     Steve Whitehouse     : Added error_report functions
  16  *     Steve Whitehouse     : Added default router detection
  17  *     Steve Whitehouse     : Hop counts in outgoing messages
  18  *     Steve Whitehouse     : Fixed src/dst in outgoing messages so
  19  *                            forwarding now stands a good chance of
  20  *                            working.
  21  *     Steve Whitehouse     : Fixed neighbour states (for now anyway).
  22  *     Steve Whitehouse     : Made error_report functions dummies. This
  23  *                            is not the right place to return skbs.
  24  *     Steve Whitehouse     : Convert to seq_file
  25  *
  26  */
  27
  28 #include <linux/net.h>
  29 #include <linux/module.h>
  30 #include <linux/socket.h>
  31 #include <linux/if_arp.h>
  32 #include <linux/slab.h>
  33 #include <linux/if_ether.h>
  34 #include <linux/init.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/string.h>
  37 #include <linux/netfilter_decnet.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/seq_file.h>
  40 #include <linux/rcupdate.h>
  41 #include <linux/jhash.h>
  42 #include <linux/atomic.h>
  43 #include <net/net_namespace.h>
  44 #include <net/neighbour.h>
  45 #include <net/dst.h>
  46 #include <net/flow.h>
  47 #include <net/dn.h>
  48 #include <net/dn_dev.h>
  49 #include <net/dn_neigh.h>
  50 #include <net/dn_route.h>
  51
  52 static int dn_neigh_construct(struct neighbour *);
  53 static void dn_neigh_error_report(struct neighbour *, struct sk_buff *);
  54 static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb);
  55
  56 /*
  57  * Operations for adding the link layer header.
  58  */
  59 static const struct neigh_ops dn_neigh_ops = {
  60         .family =               AF_DECnet,
  61         .error_report =         dn_neigh_error_report,
  62         .output =               dn_neigh_output,
  63         .connected_output =     dn_neigh_output,
  64 };
  65
  66 static u32 dn_neigh_hash(const void *pkey,
  67                          const struct net_device *dev,
  68                          __u32 *hash_rnd)
  69 {
  70         return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
  71 }
  72
  73 static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)
  74 {
  75         return neigh_key_eq16(neigh, pkey);
  76 }
  77
  78 struct neigh_table dn_neigh_table = {
  79         .family =                       PF_DECnet,
  80         .entry_size =                   NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
  81         .key_len =                      sizeof(__le16),
  82         .protocol =                     cpu_to_be16(ETH_P_DNA_RT),
  83         .hash =                         dn_neigh_hash,
  84         .key_eq =                       dn_key_eq,
  85         .constructor =                  dn_neigh_construct,
  86         .id =                           "dn_neigh_cache",
  87         .parms ={
  88                 .tbl =                  &dn_neigh_table,
  89                 .reachable_time =       30 * HZ,
  90                 .data = {
  91                         [NEIGH_VAR_MCAST_PROBES] = 0,
  92                         [NEIGH_VAR_UCAST_PROBES] = 0,
  93                         [NEIGH_VAR_APP_PROBES] = 0,
  94                         [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
  95                         [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
  96                         [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
  97                         [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
  98                         [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
  99                         [NEIGH_VAR_PROXY_QLEN] = 0,
 100                         [NEIGH_VAR_ANYCAST_DELAY] = 0,
 101                         [NEIGH_VAR_PROXY_DELAY] = 0,
 102                         [NEIGH_VAR_LOCKTIME] = 1 * HZ,
 103                 },
 104         },
 105         .gc_interval =                  30 * HZ,
 106         .gc_thresh1 =                   128,
 107         .gc_thresh2 =                   512,
 108         .gc_thresh3 =                   1024,
 109 };
 110
 111 static int dn_neigh_construct(struct neighbour *neigh)
 112 {
 113         struct net_device *dev = neigh->dev;
 114         struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
 115         struct dn_dev *dn_db;
 116         struct neigh_parms *parms;
 117
 118         rcu_read_lock();
 119         dn_db = rcu_dereference(dev->dn_ptr);
 120         if (dn_db == NULL) {
 121                 rcu_read_unlock();
 122                 return -EINVAL;
 123         }
 124
 125         parms = dn_db->neigh_parms;
 126         if (!parms) {
 127                 rcu_read_unlock();
 128                 return -EINVAL;
 129         }
 130
 131         __neigh_parms_put(neigh->parms);
 132         neigh->parms = neigh_parms_clone(parms);
 133         rcu_read_unlock();
 134
 135         neigh->ops = &dn_neigh_ops;
 136         neigh->nud_state = NUD_NOARP;
 137         neigh->output = neigh->ops->connected_output;
 138
 139         if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
 140                 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 141         else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
 142                 dn_dn2eth(neigh->ha, dn->addr);
 143         else {
 144                 net_dbg_ratelimited("Trying to create neigh for hw %d\n",
 145                                     dev->type);
 146                 return -EINVAL;
 147         }
 148
 149         /*
 150          * Make an estimate of the remote block size by assuming that its
 151          * two less then the device mtu, which it true for ethernet (and
 152          * other things which support long format headers) since there is
 153          * an extra length field (of 16 bits) which isn't part of the
 154          * ethernet headers and which the DECnet specs won't admit is part
 155          * of the DECnet routing headers either.
 156          *
 157          * If we over estimate here its no big deal, the NSP negotiations
 158          * will prevent us from sending packets which are too large for the
 159          * remote node to handle. In any case this figure is normally updated
 160          * by a hello message in most cases.
 161          */
 162         dn->blksize = dev->mtu - 2;
 163
 164         return 0;
 165 }
 166
 167 static void dn_neigh_error_report(struct neighbour *neigh, struct sk_buff *skb)
 168 {
 169         printk(KERN_DEBUG "dn_neigh_error_report: called\n");
 170         kfree_skb(skb);
 171 }
 172
 173 static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb)
 174 {
 175         struct dst_entry *dst = skb_dst(skb);
 176         struct dn_route *rt = (struct dn_route *)dst;
 177         struct net_device *dev = neigh->dev;
 178         char mac_addr[ETH_ALEN];
 179         unsigned int seq;
 180         int err;
 181
 182         dn_dn2eth(mac_addr, rt->rt_local_src);
 183         do {
 184                 seq = read_seqbegin(&neigh->ha_lock);
 185                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
 186                                       neigh->ha, mac_addr, skb->len);
 187         } while (read_seqretry(&neigh->ha_lock, seq));
 188
 189         if (err >= 0)
 190                 err = dev_queue_xmit(skb);
 191         else {
 192                 kfree_skb(skb);
 193                 err = -EINVAL;
 194         }
 195         return err;
 196 }
 197
 198 static int dn_neigh_output_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
 199 {
 200         struct dst_entry *dst = skb_dst(skb);
 201         struct dn_route *rt = (struct dn_route *)dst;
 202         struct neighbour *neigh = rt->n;
 203
 204         return neigh->output(neigh, skb);
 205 }
 206
 207 /*
 208  * For talking to broadcast devices: Ethernet & PPP
 209  */
 210 static int dn_long_output(struct neighbour *neigh, struct sock *sk,
 211                           struct sk_buff *skb)
 212 {
 213         struct net_device *dev = neigh->dev;
 214         int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
 215         unsigned char *data;
 216         struct dn_long_packet *lp;
 217         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 218
 219
 220         if (skb_headroom(skb) < headroom) {
 221                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 222                 if (skb2 == NULL) {
 223                         net_crit_ratelimited("dn_long_output: no memory\n");
 224                         kfree_skb(skb);
 225                         return -ENOBUFS;
 226                 }
 227                 consume_skb(skb);
 228                 skb = skb2;
 229                 net_info_ratelimited("dn_long_output: Increasing headroom\n");
 230         }
 231
 232         data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
 233         lp = (struct dn_long_packet *)(data+3);
 234
 235         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 236         *(data + 2) = 1 | DN_RT_F_PF; /* Padding */
 237
 238         lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
 239         lp->d_area   = lp->d_subarea = 0;
 240         dn_dn2eth(lp->d_id, cb->dst);
 241         lp->s_area   = lp->s_subarea = 0;
 242         dn_dn2eth(lp->s_id, cb->src);
 243         lp->nl2      = 0;
 244         lp->visit_ct = cb->hops & 0x3f;
 245         lp->s_class  = 0;
 246         lp->pt       = 0;
 247
 248         skb_reset_network_header(skb);
 249
 250         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
 251                        &init_net, sk, skb, NULL, neigh->dev,
 252                        dn_neigh_output_packet);
 253 }
 254
 255 /*
 256  * For talking to pointopoint and multidrop devices: DDCMP and X.25
 257  */
 258 static int dn_short_output(struct neighbour *neigh, struct sock *sk,
 259                            struct sk_buff *skb)
 260 {
 261         struct net_device *dev = neigh->dev;
 262         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 263         struct dn_short_packet *sp;
 264         unsigned char *data;
 265         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 266
 267
 268         if (skb_headroom(skb) < headroom) {
 269                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 270                 if (skb2 == NULL) {
 271                         net_crit_ratelimited("dn_short_output: no memory\n");
 272                         kfree_skb(skb);
 273                         return -ENOBUFS;
 274                 }
 275                 consume_skb(skb);
 276                 skb = skb2;
 277                 net_info_ratelimited("dn_short_output: Increasing headroom\n");
 278         }
 279
 280         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 281         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 282         sp = (struct dn_short_packet *)(data+2);
 283
 284         sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 285         sp->dstnode    = cb->dst;
 286         sp->srcnode    = cb->src;
 287         sp->forward    = cb->hops & 0x3f;
 288
 289         skb_reset_network_header(skb);
 290
 291         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
 292                        &init_net, sk, skb, NULL, neigh->dev,
 293                        dn_neigh_output_packet);
 294 }
 295
 296 /*
 297  * For talking to DECnet phase III nodes
 298  * Phase 3 output is the same as short output, execpt that
 299  * it clears the area bits before transmission.
 300  */
 301 static int dn_phase3_output(struct neighbour *neigh, struct sock *sk,
 302                             struct sk_buff *skb)
 303 {
 304         struct net_device *dev = neigh->dev;
 305         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
 306         struct dn_short_packet *sp;
 307         unsigned char *data;
 308         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 309
 310         if (skb_headroom(skb) < headroom) {
 311                 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
 312                 if (skb2 == NULL) {
 313                         net_crit_ratelimited("dn_phase3_output: no memory\n");
 314                         kfree_skb(skb);
 315                         return -ENOBUFS;
 316                 }
 317                 consume_skb(skb);
 318                 skb = skb2;
 319                 net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
 320         }
 321
 322         data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
 323         *((__le16 *)data) = cpu_to_le16(skb->len - 2);
 324         sp = (struct dn_short_packet *)(data + 2);
 325
 326         sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
 327         sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
 328         sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
 329         sp->forward  = cb->hops & 0x3f;
 330
 331         skb_reset_network_header(skb);
 332
 333         return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
 334                        &init_net, sk, skb, NULL, neigh->dev,
 335                        dn_neigh_output_packet);
 336 }
 337
 338 int dn_to_neigh_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 339 {
 340         struct dst_entry *dst = skb_dst(skb);
 341         struct dn_route *rt = (struct dn_route *) dst;
 342         struct neighbour *neigh = rt->n;
 343         struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
 344         struct dn_dev *dn_db;
 345         bool use_long;
 346
 347         rcu_read_lock();
 348         dn_db = rcu_dereference(neigh->dev->dn_ptr);
 349         if (dn_db == NULL) {
 350                 rcu_read_unlock();
 351                 return -EINVAL;
 352         }
 353         use_long = dn_db->use_long;
 354         rcu_read_unlock();
 355
 356         if (dn->flags & DN_NDFLAG_P3)
 357                 return dn_phase3_output(neigh, sk, skb);
 358         if (use_long)
 359                 return dn_long_output(neigh, sk, skb);
 360         else
 361                 return dn_short_output(neigh, sk, skb);
 362 }
 363
 364 /*
 365  * Unfortunately, the neighbour code uses the device in its hash
 366  * function, so we don't get any advantage from it. This function
 367  * basically does a neigh_lookup(), but without comparing the device
 368  * field. This is required for the On-Ethernet cache
 369  */
 370
 371 /*
 372  * Pointopoint link receives a hello message
 373  */
 374 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 375 {
 376         kfree_skb(skb);
 377 }
 378
 379 /*
 380  * Ethernet router hello message received
 381  */
 382 int dn_neigh_router_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
 383 {
 384         struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 385
 386         struct neighbour *neigh;
 387         struct dn_neigh *dn;
 388         struct dn_dev *dn_db;
 389         __le16 src;
 390
 391         src = dn_eth2dn(msg->id);
 392
 393         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 394
 395         dn = container_of(neigh, struct dn_neigh, n);
 396
 397         if (neigh) {
 398                 write_lock(&neigh->lock);
 399
 400                 neigh->used = jiffies;
 401                 dn_db = rcu_dereference(neigh->dev->dn_ptr);
 402
 403                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 404                         neigh->updated = jiffies;
 405
 406                         if (neigh->dev->type == ARPHRD_ETHER)
 407                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 408
 409                         dn->blksize  = le16_to_cpu(msg->blksize);
 410                         dn->priority = msg->priority;
 411
 412                         dn->flags &= ~DN_NDFLAG_P3;
 413
 414                         switch (msg->iinfo & DN_RT_INFO_TYPE) {
 415                         case DN_RT_INFO_L1RT:
 416                                 dn->flags &=~DN_NDFLAG_R2;
 417                                 dn->flags |= DN_NDFLAG_R1;
 418                                 break;
 419                         case DN_RT_INFO_L2RT:
 420                                 dn->flags |= DN_NDFLAG_R2;
 421                         }
 422                 }
 423
 424                 /* Only use routers in our area */
 425                 if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
 426                         if (!dn_db->router) {
 427                                 dn_db->router = neigh_clone(neigh);
 428                         } else {
 429                                 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
 430                                         neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
 431                         }
 432                 }
 433                 write_unlock(&neigh->lock);
 434                 neigh_release(neigh);
 435         }
 436
 437         kfree_skb(skb);
 438         return 0;
 439 }
 440
 441 /*
 442  * Endnode hello message received
 443  */
 444 int dn_neigh_endnode_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
 445 {
 446         struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 447         struct neighbour *neigh;
 448         struct dn_neigh *dn;
 449         __le16 src;
 450
 451         src = dn_eth2dn(msg->id);
 452
 453         neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
 454
 455         dn = container_of(neigh, struct dn_neigh, n);
 456
 457         if (neigh) {
 458                 write_lock(&neigh->lock);
 459
 460                 neigh->used = jiffies;
 461
 462                 if (!(neigh->nud_state & NUD_PERMANENT)) {
 463                         neigh->updated = jiffies;
 464
 465                         if (neigh->dev->type == ARPHRD_ETHER)
 466                                 memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
 467                         dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
 468                         dn->blksize  = le16_to_cpu(msg->blksize);
 469                         dn->priority = 0;
 470                 }
 471
 472                 write_unlock(&neigh->lock);
 473                 neigh_release(neigh);
 474         }
 475
 476         kfree_skb(skb);
 477         return 0;
 478 }
 479
 480 static char *dn_find_slot(char *base, int max, int priority)
 481 {
 482         int i;
 483         unsigned char *min = NULL;
 484
 485         base += 6; /* skip first id */
 486
 487         for(i = 0; i < max; i++) {
 488                 if (!min || (*base < *min))
 489                         min = base;
 490                 base += 7; /* find next priority */
 491         }
 492
 493         if (!min)
 494                 return NULL;
 495
 496         return (*min < priority) ? (min - 6) : NULL;
 497 }
 498
 499 struct elist_cb_state {
 500         struct net_device *dev;
 501         unsigned char *ptr;
 502         unsigned char *rs;
 503         int t, n;
 504 };
 505
 506 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
 507 {
 508         struct elist_cb_state *s = _info;
 509         struct dn_neigh *dn;
 510
 511         if (neigh->dev != s->dev)
 512                 return;
 513
 514         dn = container_of(neigh, struct dn_neigh, n);
 515         if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
 516                 return;
 517
 518         if (s->t == s->n)
 519                 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
 520         else
 521                 s->t++;
 522         if (s->rs == NULL)
 523                 return;
 524
 525         dn_dn2eth(s->rs, dn->addr);
 526         s->rs += 6;
 527         *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
 528         *(s->rs) |= dn->priority;
 529         s->rs++;
 530 }
 531
 532 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
 533 {
 534         struct elist_cb_state state;
 535
 536         state.dev = dev;
 537         state.t = 0;
 538         state.n = n;
 539         state.ptr = ptr;
 540         state.rs = ptr;
 541
 542         neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
 543
 544         return state.t;
 545 }
 546
 547
 548 #ifdef CONFIG_PROC_FS
 549
 550 static inline void dn_neigh_format_entry(struct seq_file *seq,
 551                                          struct neighbour *n)
 552 {
 553         struct dn_neigh *dn = container_of(n, struct dn_neigh, n);
 554         char buf[DN_ASCBUF_LEN];
 555
 556         read_lock(&n->lock);
 557         seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
 558                    dn_addr2asc(le16_to_cpu(dn->addr), buf),
 559                    (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
 560                    (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
 561                    (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
 562                    dn->n.nud_state,
 563                    refcount_read(&dn->n.refcnt),
 564                    dn->blksize,
 565                    (dn->n.dev) ? dn->n.dev->name : "?");
 566         read_unlock(&n->lock);
 567 }
 568
 569 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
 570 {
 571         if (v == SEQ_START_TOKEN) {
 572                 seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
 573         } else {
 574                 dn_neigh_format_entry(seq, v);
 575         }
 576
 577         return 0;
 578 }
 579
 580 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
 581 {
 582         return neigh_seq_start(seq, pos, &dn_neigh_table,
 583                                NEIGH_SEQ_NEIGH_ONLY);
 584 }
 585
 586 static const struct seq_operations dn_neigh_seq_ops = {
 587         .start = dn_neigh_seq_start,
 588         .next  = neigh_seq_next,
 589         .stop  = neigh_seq_stop,
 590         .show  = dn_neigh_seq_show,
 591 };
 592 #endif
 593
 594 void __init dn_neigh_init(void)
 595 {
 596         neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
 597         proc_create_net("decnet_neigh", 0444, init_net.proc_net,
 598                         &dn_neigh_seq_ops, sizeof(struct neigh_seq_state));
 599 }
 600
 601 void __exit dn_neigh_cleanup(void)
 602 {
 603         remove_proc_entry("decnet_neigh", init_net.proc_net);
 604         neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
 605 }