net/802/tr.c

   1 /*
   2  * NET3:        Token ring device handling subroutines
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Fixes:       3 Feb 97 Paul Norton <pnorton@cts.com> Minor routing fixes.
  10  *              Added rif table to /proc/net/tr_rif and rif timeout to
  11  *              /proc/sys/net/token-ring/rif_timeout.
  12  *              22 Jun 98 Paul Norton <p.norton@computer.org> Rearranged
  13  *              tr_header and tr_type_trans to handle passing IPX SNAP and
  14  *              802.2 through the correct layers. Eliminated tr_reformat.
  15  *
  16  */
  17
  18 #include <asm/uaccess.h>
  19 #include <asm/system.h>
  20 #include <linux/module.h>
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/jiffies.h>
  24 #include <linux/string.h>
  25 #include <linux/mm.h>
  26 #include <linux/socket.h>
  27 #include <linux/in.h>
  28 #include <linux/inet.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/trdevice.h>
  31 #include <linux/skbuff.h>
  32 #include <linux/errno.h>
  33 #include <linux/timer.h>
  34 #include <linux/net.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/init.h>
  38 #include <linux/sysctl.h>
  39 #include <linux/slab.h>
  40 #include <net/arp.h>
  41 #include <net/net_namespace.h>
  42
  43 static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev);
  44 static void rif_check_expire(unsigned long dummy);
  45
  46 #define TR_SR_DEBUG 0
  47
  48 /*
  49  *      Each RIF entry we learn is kept this way
  50  */
  51
  52 struct rif_cache {
  53         unsigned char addr[TR_ALEN];
  54         int iface;
  55         __be16 rcf;
  56         __be16 rseg[8];
  57         struct rif_cache *next;
  58         unsigned long last_used;
  59         unsigned char local_ring;
  60 };
  61
  62 #define RIF_TABLE_SIZE 32
  63
  64 /*
  65  *      We hash the RIF cache 32 ways. We do after all have to look it
  66  *      up a lot.
  67  */
  68
  69 static struct rif_cache *rif_table[RIF_TABLE_SIZE];
  70
  71 static DEFINE_SPINLOCK(rif_lock);
  72
  73
  74 /*
  75  *      Garbage disposal timer.
  76  */
  77
  78 static struct timer_list rif_timer;
  79
  80 static int sysctl_tr_rif_timeout = 60*10*HZ;
  81
  82 static inline unsigned long rif_hash(const unsigned char *addr)
  83 {
  84         unsigned long x;
  85
  86         x = addr[0];
  87         x = (x << 2) ^ addr[1];
  88         x = (x << 2) ^ addr[2];
  89         x = (x << 2) ^ addr[3];
  90         x = (x << 2) ^ addr[4];
  91         x = (x << 2) ^ addr[5];
  92
  93         x ^= x >> 8;
  94
  95         return x & (RIF_TABLE_SIZE - 1);
  96 }
  97
  98 /*
  99  *      Put the headers on a token ring packet. Token ring source routing
 100  *      makes this a little more exciting than on ethernet.
 101  */
 102
 103 static int tr_header(struct sk_buff *skb, struct net_device *dev,
 104                      unsigned short type,
 105                      const void *daddr, const void *saddr, unsigned len)
 106 {
 107         struct trh_hdr *trh;
 108         int hdr_len;
 109
 110         /*
 111          * Add the 802.2 SNAP header if IP as the IPv4/IPv6 code calls
 112          * dev->hard_header directly.
 113          */
 114         if (type == ETH_P_IP || type == ETH_P_IPV6 || type == ETH_P_ARP)
 115         {
 116                 struct trllc *trllc;
 117
 118                 hdr_len = sizeof(struct trh_hdr) + sizeof(struct trllc);
 119                 trh = (struct trh_hdr *)skb_push(skb, hdr_len);
 120                 trllc = (struct trllc *)(trh+1);
 121                 trllc->dsap = trllc->ssap = EXTENDED_SAP;
 122                 trllc->llc = UI_CMD;
 123                 trllc->protid[0] = trllc->protid[1] = trllc->protid[2] = 0x00;
 124                 trllc->ethertype = htons(type);
 125         }
 126         else
 127         {
 128                 hdr_len = sizeof(struct trh_hdr);
 129                 trh = (struct trh_hdr *)skb_push(skb, hdr_len);
 130         }
 131
 132         trh->ac=AC;
 133         trh->fc=LLC_FRAME;
 134
 135         if(saddr)
 136                 memcpy(trh->saddr,saddr,dev->addr_len);
 137         else
 138                 memcpy(trh->saddr,dev->dev_addr,dev->addr_len);
 139
 140         /*
 141          *      Build the destination and then source route the frame
 142          */
 143
 144         if(daddr)
 145         {
 146                 memcpy(trh->daddr,daddr,dev->addr_len);
 147                 tr_source_route(skb, trh, dev);
 148                 return hdr_len;
 149         }
 150
 151         return -hdr_len;
 152 }
 153
 154 /*
 155  *      A neighbour discovery of some species (eg arp) has completed. We
 156  *      can now send the packet.
 157  */
 158
 159 static int tr_rebuild_header(struct sk_buff *skb)
 160 {
 161         struct trh_hdr *trh=(struct trh_hdr *)skb->data;
 162         struct trllc *trllc=(struct trllc *)(skb->data+sizeof(struct trh_hdr));
 163         struct net_device *dev = skb->dev;
 164
 165         /*
 166          *      FIXME: We don't yet support IPv6 over token rings
 167          */
 168
 169         if(trllc->ethertype != htons(ETH_P_IP)) {
 170                 printk("tr_rebuild_header: Don't know how to resolve type %04X addresses ?\n", ntohs(trllc->ethertype));
 171                 return 0;
 172         }
 173
 174 #ifdef CONFIG_INET
 175         if(arp_find(trh->daddr, skb)) {
 176                         return 1;
 177         }
 178         else
 179 #endif
 180         {
 181                 tr_source_route(skb,trh,dev);
 182                 return 0;
 183         }
 184 }
 185
 186 /*
 187  *      Some of this is a bit hackish. We intercept RIF information
 188  *      used for source routing. We also grab IP directly and don't feed
 189  *      it via SNAP.
 190  */
 191
 192 __be16 tr_type_trans(struct sk_buff *skb, struct net_device *dev)
 193 {
 194
 195         struct trh_hdr *trh;
 196         struct trllc *trllc;
 197         unsigned riflen=0;
 198
 199         skb->dev = dev;
 200         skb_reset_mac_header(skb);
 201         trh = tr_hdr(skb);
 202
 203         if(trh->saddr[0] & TR_RII)
 204                 riflen = (ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8;
 205
 206         trllc = (struct trllc *)(skb->data+sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);
 207
 208         skb_pull(skb,sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);
 209
 210         if(*trh->daddr & 0x80)
 211         {
 212                 if(!memcmp(trh->daddr,dev->broadcast,TR_ALEN))
 213                         skb->pkt_type=PACKET_BROADCAST;
 214                 else
 215                         skb->pkt_type=PACKET_MULTICAST;
 216         }
 217         else if ( (trh->daddr[0] & 0x01) && (trh->daddr[1] & 0x00) && (trh->daddr[2] & 0x5E))
 218         {
 219                 skb->pkt_type=PACKET_MULTICAST;
 220         }
 221         else if(dev->flags & IFF_PROMISC)
 222         {
 223                 if(memcmp(trh->daddr, dev->dev_addr, TR_ALEN))
 224                         skb->pkt_type=PACKET_OTHERHOST;
 225         }
 226
 227         if ((skb->pkt_type != PACKET_BROADCAST) &&
 228             (skb->pkt_type != PACKET_MULTICAST))
 229                 tr_add_rif_info(trh,dev) ;
 230
 231         /*
 232          * Strip the SNAP header from ARP packets since we don't
 233          * pass them through to the 802.2/SNAP layers.
 234          */
 235
 236         if (trllc->dsap == EXTENDED_SAP &&
 237             (trllc->ethertype == htons(ETH_P_IP) ||
 238              trllc->ethertype == htons(ETH_P_IPV6) ||
 239              trllc->ethertype == htons(ETH_P_ARP)))
 240         {
 241                 skb_pull(skb, sizeof(struct trllc));
 242                 return trllc->ethertype;
 243         }
 244
 245         return htons(ETH_P_TR_802_2);
 246 }
 247
 248 /*
 249  *      We try to do source routing...
 250  */
 251
 252 void tr_source_route(struct sk_buff *skb,struct trh_hdr *trh,
 253                      struct net_device *dev)
 254 {
 255         int slack;
 256         unsigned int hash;
 257         struct rif_cache *entry;
 258         unsigned char *olddata;
 259         unsigned long flags;
 260         static const unsigned char mcast_func_addr[]
 261                 = {0xC0,0x00,0x00,0x04,0x00,0x00};
 262
 263         spin_lock_irqsave(&rif_lock, flags);
 264
 265         /*
 266          *      Broadcasts are single route as stated in RFC 1042
 267          */
 268         if( (!memcmp(&(trh->daddr[0]),&(dev->broadcast[0]),TR_ALEN)) ||
 269             (!memcmp(&(trh->daddr[0]),&(mcast_func_addr[0]), TR_ALEN))  )
 270         {
 271                 trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)
 272                                | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);
 273                 trh->saddr[0]|=TR_RII;
 274         }
 275         else
 276         {
 277                 hash = rif_hash(trh->daddr);
 278                 /*
 279                  *      Walk the hash table and look for an entry
 280                  */
 281                 for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->daddr[0]),TR_ALEN);entry=entry->next);
 282
 283                 /*
 284                  *      If we found an entry we can route the frame.
 285                  */
 286                 if(entry)
 287                 {
 288 #if TR_SR_DEBUG
 289 printk("source routing for %pM\n", trh->daddr);
 290 #endif
 291                         if(!entry->local_ring && (ntohs(entry->rcf) & TR_RCF_LEN_MASK) >> 8)
 292                         {
 293                                 trh->rcf=entry->rcf;
 294                                 memcpy(&trh->rseg[0],&entry->rseg[0],8*sizeof(unsigned short));
 295                                 trh->rcf^=htons(TR_RCF_DIR_BIT);
 296                                 trh->rcf&=htons(0x1fff);        /* Issam Chehab <ichehab@madge1.demon.co.uk> */
 297
 298                                 trh->saddr[0]|=TR_RII;
 299 #if TR_SR_DEBUG
 300                                 printk("entry found with rcf %04x\n", entry->rcf);
 301                         }
 302                         else
 303                         {
 304                                 printk("entry found but without rcf length, local=%02x\n", entry->local_ring);
 305 #endif
 306                         }
 307                         entry->last_used=jiffies;
 308                 }
 309                 else
 310                 {
 311                         /*
 312                          *      Without the information we simply have to shout
 313                          *      on the wire. The replies should rapidly clean this
 314                          *      situation up.
 315                          */
 316                         trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)
 317                                        | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);
 318                         trh->saddr[0]|=TR_RII;
 319 #if TR_SR_DEBUG
 320                         printk("no entry in rif table found - broadcasting frame\n");
 321 #endif
 322                 }
 323         }
 324
 325         /* Compress the RIF here so we don't have to do it in the driver(s) */
 326         if (!(trh->saddr[0] & 0x80))
 327                 slack = 18;
 328         else
 329                 slack = 18 - ((ntohs(trh->rcf) & TR_RCF_LEN_MASK)>>8);
 330         olddata = skb->data;
 331         spin_unlock_irqrestore(&rif_lock, flags);
 332
 333         skb_pull(skb, slack);
 334         memmove(skb->data, olddata, sizeof(struct trh_hdr) - slack);
 335 }
 336
 337 /*
 338  *      We have learned some new RIF information for our source
 339  *      routing.
 340  */
 341
 342 static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev)
 343 {
 344         unsigned int hash, rii_p = 0;
 345         unsigned long flags;
 346         struct rif_cache *entry;
 347         unsigned char saddr0;
 348
 349         spin_lock_irqsave(&rif_lock, flags);
 350         saddr0 = trh->saddr[0];
 351
 352         /*
 353          *      Firstly see if the entry exists
 354          */
 355
 356         if(trh->saddr[0] & TR_RII)
 357         {
 358                 trh->saddr[0]&=0x7f;
 359                 if (((ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8) > 2)
 360                 {
 361                         rii_p = 1;
 362                 }
 363         }
 364
 365         hash = rif_hash(trh->saddr);
 366         for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);entry=entry->next);
 367
 368         if(entry==NULL)
 369         {
 370 #if TR_SR_DEBUG
 371                 printk("adding rif_entry: addr:%pM rcf:%04X\n",
 372                        trh->saddr, ntohs(trh->rcf));
 373 #endif
 374                 /*
 375                  *      Allocate our new entry. A failure to allocate loses
 376                  *      use the information. This is harmless.
 377                  *
 378                  *      FIXME: We ought to keep some kind of cache size
 379                  *      limiting and adjust the timers to suit.
 380                  */
 381                 entry=kmalloc(sizeof(struct rif_cache),GFP_ATOMIC);
 382
 383                 if(!entry)
 384                 {
 385                         printk(KERN_DEBUG "tr.c: Couldn't malloc rif cache entry !\n");
 386                         spin_unlock_irqrestore(&rif_lock, flags);
 387                         return;
 388                 }
 389
 390                 memcpy(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);
 391                 entry->iface = dev->ifindex;
 392                 entry->next=rif_table[hash];
 393                 entry->last_used=jiffies;
 394                 rif_table[hash]=entry;
 395
 396                 if (rii_p)
 397                 {
 398                         entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
 399                         memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
 400                         entry->local_ring = 0;
 401                 }
 402                 else
 403                 {
 404                         entry->local_ring = 1;
 405                 }
 406         }
 407         else    /* Y. Tahara added */
 408         {
 409                 /*
 410                  *      Update existing entries
 411                  */
 412                 if (!entry->local_ring)
 413                     if (entry->rcf != (trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK)) &&
 414                          !(trh->rcf & htons(TR_RCF_BROADCAST_MASK)))
 415                     {
 416 #if TR_SR_DEBUG
 417 printk("updating rif_entry: addr:%pM rcf:%04X\n",
 418                 trh->saddr, ntohs(trh->rcf));
 419 #endif
 420                             entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
 421                             memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
 422                     }
 423                 entry->last_used=jiffies;
 424         }
 425         trh->saddr[0]=saddr0; /* put the routing indicator back for tcpdump */
 426         spin_unlock_irqrestore(&rif_lock, flags);
 427 }
 428
 429 /*
 430  *      Scan the cache with a timer and see what we need to throw out.
 431  */
 432
 433 static void rif_check_expire(unsigned long dummy)
 434 {
 435         int i;
 436         unsigned long flags, next_interval = jiffies + sysctl_tr_rif_timeout/2;
 437
 438         spin_lock_irqsave(&rif_lock, flags);
 439
 440         for(i =0; i < RIF_TABLE_SIZE; i++) {
 441                 struct rif_cache *entry, **pentry;
 442
 443                 pentry = rif_table+i;
 444                 while((entry=*pentry) != NULL) {
 445                         unsigned long expires
 446                                 = entry->last_used + sysctl_tr_rif_timeout;
 447
 448                         if (time_before_eq(expires, jiffies)) {
 449                                 *pentry = entry->next;
 450                                 kfree(entry);
 451                         } else {
 452                                 pentry = &entry->next;
 453
 454                                 if (time_before(expires, next_interval))
 455                                         next_interval = expires;
 456                         }
 457                 }
 458         }
 459
 460         spin_unlock_irqrestore(&rif_lock, flags);
 461
 462         mod_timer(&rif_timer, next_interval);
 463
 464 }
 465
 466 /*
 467  *      Generate the /proc/net information for the token ring RIF
 468  *      routing.
 469  */
 470
 471 #ifdef CONFIG_PROC_FS
 472
 473 static struct rif_cache *rif_get_idx(loff_t pos)
 474 {
 475         int i;
 476         struct rif_cache *entry;
 477         loff_t off = 0;
 478
 479         for(i = 0; i < RIF_TABLE_SIZE; i++)
 480                 for(entry = rif_table[i]; entry; entry = entry->next) {
 481                         if (off == pos)
 482                                 return entry;
 483                         ++off;
 484                 }
 485
 486         return NULL;
 487 }
 488
 489 static void *rif_seq_start(struct seq_file *seq, loff_t *pos)
 490         __acquires(&rif_lock)
 491 {
 492         spin_lock_irq(&rif_lock);
 493
 494         return *pos ? rif_get_idx(*pos - 1) : SEQ_START_TOKEN;
 495 }
 496
 497 static void *rif_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 498 {
 499         int i;
 500         struct rif_cache *ent = v;
 501
 502         ++*pos;
 503
 504         if (v == SEQ_START_TOKEN) {
 505                 i = -1;
 506                 goto scan;
 507         }
 508
 509         if (ent->next)
 510                 return ent->next;
 511
 512         i = rif_hash(ent->addr);
 513  scan:
 514         while (++i < RIF_TABLE_SIZE) {
 515                 if ((ent = rif_table[i]) != NULL)
 516                         return ent;
 517         }
 518         return NULL;
 519 }
 520
 521 static void rif_seq_stop(struct seq_file *seq, void *v)
 522         __releases(&rif_lock)
 523 {
 524         spin_unlock_irq(&rif_lock);
 525 }
 526
 527 static int rif_seq_show(struct seq_file *seq, void *v)
 528 {
 529         int j, rcf_len, segment, brdgnmb;
 530         struct rif_cache *entry = v;
 531
 532         if (v == SEQ_START_TOKEN)
 533                 seq_puts(seq,
 534                      "if     TR address       TTL   rcf   routing segments\n");
 535         else {
 536                 struct net_device *dev = dev_get_by_index(&init_net, entry->iface);
 537                 long ttl = (long) (entry->last_used + sysctl_tr_rif_timeout)
 538                                 - (long) jiffies;
 539
 540                 seq_printf(seq, "%s %pM %7li ",
 541                            dev?dev->name:"?",
 542                            entry->addr,
 543                            ttl/HZ);
 544
 545                         if (entry->local_ring)
 546                                 seq_puts(seq, "local\n");
 547                         else {
 548
 549                                 seq_printf(seq, "%04X", ntohs(entry->rcf));
 550                                 rcf_len = ((ntohs(entry->rcf) & TR_RCF_LEN_MASK)>>8)-2;
 551                                 if (rcf_len)
 552                                         rcf_len >>= 1;
 553                                 for(j = 1; j < rcf_len; j++) {
 554                                         if(j==1) {
 555                                                 segment=ntohs(entry->rseg[j-1])>>4;
 556                                                 seq_printf(seq,"  %03X",segment);
 557                                         }
 558
 559                                         segment=ntohs(entry->rseg[j])>>4;
 560                                         brdgnmb=ntohs(entry->rseg[j-1])&0x00f;
 561                                         seq_printf(seq,"-%01X-%03X",brdgnmb,segment);
 562                                 }
 563                                 seq_putc(seq, '\n');
 564                         }
 565
 566                 if (dev)
 567                         dev_put(dev);
 568                 }
 569         return 0;
 570 }
 571
 572
 573 static const struct seq_operations rif_seq_ops = {
 574         .start = rif_seq_start,
 575         .next  = rif_seq_next,
 576         .stop  = rif_seq_stop,
 577         .show  = rif_seq_show,
 578 };
 579
 580 static int rif_seq_open(struct inode *inode, struct file *file)
 581 {
 582         return seq_open(file, &rif_seq_ops);
 583 }
 584
 585 static const struct file_operations rif_seq_fops = {
 586         .owner   = THIS_MODULE,
 587         .open    = rif_seq_open,
 588         .read    = seq_read,
 589         .llseek  = seq_lseek,
 590         .release = seq_release,
 591 };
 592
 593 #endif
 594
 595 static const struct header_ops tr_header_ops = {
 596         .create = tr_header,
 597         .rebuild= tr_rebuild_header,
 598 };
 599
 600 static void tr_setup(struct net_device *dev)
 601 {
 602         /*
 603          *      Configure and register
 604          */
 605
 606         dev->header_ops = &tr_header_ops;
 607
 608         dev->type               = ARPHRD_IEEE802_TR;
 609         dev->hard_header_len    = TR_HLEN;
 610         dev->mtu                = 2000;
 611         dev->addr_len           = TR_ALEN;
 612         dev->tx_queue_len       = 100;  /* Long queues on tr */
 613
 614         memset(dev->broadcast,0xFF, TR_ALEN);
 615
 616         /* New-style flags. */
 617         dev->flags              = IFF_BROADCAST | IFF_MULTICAST ;
 618 }
 619
 620 /**
 621  * alloc_trdev - Register token ring device
 622  * @sizeof_priv: Size of additional driver-private structure to be allocated
 623  *      for this token ring device
 624  *
 625  * Fill in the fields of the device structure with token ring-generic values.
 626  *
 627  * Constructs a new net device, complete with a private data area of
 628  * size @sizeof_priv.  A 32-byte (not bit) alignment is enforced for
 629  * this private data area.
 630  */
 631 struct net_device *alloc_trdev(int sizeof_priv)
 632 {
 633         return alloc_netdev(sizeof_priv, "tr%d", tr_setup);
 634 }
 635
 636 #ifdef CONFIG_SYSCTL
 637 static struct ctl_table tr_table[] = {
 638         {
 639                 .procname       = "rif_timeout",
 640                 .data           = &sysctl_tr_rif_timeout,
 641                 .maxlen         = sizeof(int),
 642                 .mode           = 0644,
 643                 .proc_handler   = proc_dointvec
 644         },
 645         { },
 646 };
 647
 648 static __initdata struct ctl_path tr_path[] = {
 649         { .procname = "net", },
 650         { .procname = "token-ring", },
 651         { }
 652 };
 653 #endif
 654
 655 /*
 656  *      Called during bootup.  We don't actually have to initialise
 657  *      too much for this.
 658  */
 659
 660 static int __init rif_init(void)
 661 {
 662         rif_timer.expires  = jiffies + sysctl_tr_rif_timeout;
 663         setup_timer(&rif_timer, rif_check_expire, 0);
 664         add_timer(&rif_timer);
 665 #ifdef CONFIG_SYSCTL
 666         register_sysctl_paths(tr_path, tr_table);
 667 #endif
 668         proc_net_fops_create(&init_net, "tr_rif", S_IRUGO, &rif_seq_fops);
 669         return 0;
 670 }
 671
 672 module_init(rif_init);
 673
 674 EXPORT_SYMBOL(tr_type_trans);
 675 EXPORT_SYMBOL(alloc_trdev);
 676
 677 MODULE_LICENSE("GPL");