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