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/config.h>
  21 #include <linux/module.h>
  22 #include <linux/types.h>
  23 #include <linux/kernel.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/string.h>
  26 #include <linux/mm.h>
  27 #include <linux/socket.h>
  28 #include <linux/in.h>
  29 #include <linux/inet.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/trdevice.h>
  32 #include <linux/skbuff.h>
  33 #include <linux/errno.h>
  34 #include <linux/timer.h>
  35 #include <linux/net.h>
  36 #include <linux/proc_fs.h>
  37 #include <linux/seq_file.h>
  38 #include <linux/init.h>
  39 #include <net/arp.h>
  40
  41 static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev);
  42 static void rif_check_expire(unsigned long dummy);
  43
  44 #define TR_SR_DEBUG 0
  45
  46 /*
  47  *      Each RIF entry we learn is kept this way
  48  */
  49
  50 struct rif_cache_s {
  51         unsigned char addr[TR_ALEN];
  52         int iface;
  53         __u16 rcf;
  54         __u16 rseg[8];
  55         struct rif_cache_s *next;
  56         unsigned long last_used;
  57         unsigned char local_ring;
  58 };
  59
  60 #define RIF_TABLE_SIZE 32
  61
  62 /*
  63  *      We hash the RIF cache 32 ways. We do after all have to look it
  64  *      up a lot.
  65  */
  66
  67 static struct rif_cache_s *rif_table[RIF_TABLE_SIZE];
  68
  69 static spinlock_t rif_lock = SPIN_LOCK_UNLOCKED;
  70
  71
  72 /*
  73  *      Garbage disposal timer.
  74  */
  75
  76 static struct timer_list rif_timer;
  77
  78 int sysctl_tr_rif_timeout = 60*10*HZ;
  79
  80 static inline unsigned long rif_hash(const unsigned char *addr)
  81 {
  82         unsigned long x;
  83
  84         x = addr[0];
  85         x = (x << 2) ^ addr[1];
  86         x = (x << 2) ^ addr[2];
  87         x = (x << 2) ^ addr[3];
  88         x = (x << 2) ^ addr[4];
  89         x = (x << 2) ^ addr[5];
  90
  91         x ^= x >> 8;
  92
  93         return x & (RIF_TABLE_SIZE - 1);
  94 }
  95
  96 /*
  97  *      Put the headers on a token ring packet. Token ring source routing
  98  *      makes this a little more exciting than on ethernet.
  99  */
 100
 101 int tr_header(struct sk_buff *skb, struct net_device *dev, 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=(struct trllc *)(trh+1);
 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 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",(unsigned int)htons(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 unsigned short tr_type_trans(struct sk_buff *skb, struct net_device *dev)
 190 {
 191
 192         struct trh_hdr *trh=(struct trh_hdr *)skb->data;
 193         struct trllc *trllc;
 194         unsigned riflen=0;
 195
 196         skb->mac.raw = skb->data;
 197
 198         if(trh->saddr[0] & TR_RII)
 199                 riflen = (ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8;
 200
 201         trllc = (struct trllc *)(skb->data+sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);
 202
 203         skb_pull(skb,sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);
 204
 205         if(*trh->daddr & 0x80)
 206         {
 207                 if(!memcmp(trh->daddr,dev->broadcast,TR_ALEN))
 208                         skb->pkt_type=PACKET_BROADCAST;
 209                 else
 210                         skb->pkt_type=PACKET_MULTICAST;
 211         }
 212         else if ( (trh->daddr[0] & 0x01) && (trh->daddr[1] & 0x00) && (trh->daddr[2] & 0x5E))
 213         {
 214                 skb->pkt_type=PACKET_MULTICAST;
 215         }
 216         else if(dev->flags & IFF_PROMISC)
 217         {
 218                 if(memcmp(trh->daddr, dev->dev_addr, TR_ALEN))
 219                         skb->pkt_type=PACKET_OTHERHOST;
 220         }
 221
 222         if ((skb->pkt_type != PACKET_BROADCAST) &&
 223             (skb->pkt_type != PACKET_MULTICAST))
 224                 tr_add_rif_info(trh,dev) ;
 225
 226         /*
 227          * Strip the SNAP header from ARP packets since we don't
 228          * pass them through to the 802.2/SNAP layers.
 229          */
 230
 231         if (trllc->dsap == EXTENDED_SAP &&
 232             (trllc->ethertype == ntohs(ETH_P_IP) ||
 233              trllc->ethertype == ntohs(ETH_P_IPV6) ||
 234              trllc->ethertype == ntohs(ETH_P_ARP)))
 235         {
 236                 skb_pull(skb, sizeof(struct trllc));
 237                 return trllc->ethertype;
 238         }
 239
 240         return ntohs(ETH_P_802_2);
 241 }
 242
 243 /*
 244  *      We try to do source routing...
 245  */
 246
 247 void tr_source_route(struct sk_buff *skb,struct trh_hdr *trh,struct net_device *dev)
 248 {
 249         int slack;
 250         unsigned int hash;
 251         struct rif_cache_s *entry;
 252         unsigned char *olddata;
 253         static const unsigned char mcast_func_addr[]
 254                 = {0xC0,0x00,0x00,0x04,0x00,0x00};
 255
 256         spin_lock_bh(&rif_lock);
 257
 258         /*
 259          *      Broadcasts are single route as stated in RFC 1042
 260          */
 261         if( (!memcmp(&(trh->daddr[0]),&(dev->broadcast[0]),TR_ALEN)) ||
 262             (!memcmp(&(trh->daddr[0]),&(mcast_func_addr[0]), TR_ALEN))  )
 263         {
 264                 trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)
 265                                | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);
 266                 trh->saddr[0]|=TR_RII;
 267         }
 268         else
 269         {
 270                 hash = rif_hash(trh->daddr);
 271                 /*
 272                  *      Walk the hash table and look for an entry
 273                  */
 274                 for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->daddr[0]),TR_ALEN);entry=entry->next);
 275
 276                 /*
 277                  *      If we found an entry we can route the frame.
 278                  */
 279                 if(entry)
 280                 {
 281 #if TR_SR_DEBUG
 282 printk("source routing for %02X:%02X:%02X:%02X:%02X:%02X\n",trh->daddr[0],
 283                   trh->daddr[1],trh->daddr[2],trh->daddr[3],trh->daddr[4],trh->daddr[5]);
 284 #endif
 285                         if(!entry->local_ring && (ntohs(entry->rcf) & TR_RCF_LEN_MASK) >> 8)
 286                         {
 287                                 trh->rcf=entry->rcf;
 288                                 memcpy(&trh->rseg[0],&entry->rseg[0],8*sizeof(unsigned short));
 289                                 trh->rcf^=htons(TR_RCF_DIR_BIT);
 290                                 trh->rcf&=htons(0x1fff);        /* Issam Chehab <ichehab@madge1.demon.co.uk> */
 291
 292                                 trh->saddr[0]|=TR_RII;
 293 #if TR_SR_DEBUG
 294                                 printk("entry found with rcf %04x\n", entry->rcf);
 295                         }
 296                         else
 297                         {
 298                                 printk("entry found but without rcf length, local=%02x\n", entry->local_ring);
 299 #endif
 300                         }
 301                         entry->last_used=jiffies;
 302                 }
 303                 else
 304                 {
 305                         /*
 306                          *      Without the information we simply have to shout
 307                          *      on the wire. The replies should rapidly clean this
 308                          *      situation up.
 309                          */
 310                         trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)
 311                                        | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);
 312                         trh->saddr[0]|=TR_RII;
 313 #if TR_SR_DEBUG
 314                         printk("no entry in rif table found - broadcasting frame\n");
 315 #endif
 316                 }
 317         }
 318
 319         /* Compress the RIF here so we don't have to do it in the driver(s) */
 320         if (!(trh->saddr[0] & 0x80))
 321                 slack = 18;
 322         else
 323                 slack = 18 - ((ntohs(trh->rcf) & TR_RCF_LEN_MASK)>>8);
 324         olddata = skb->data;
 325         spin_unlock_bh(&rif_lock);
 326
 327         skb_pull(skb, slack);
 328         memmove(skb->data, olddata, sizeof(struct trh_hdr) - slack);
 329 }
 330
 331 /*
 332  *      We have learned some new RIF information for our source
 333  *      routing.
 334  */
 335
 336 static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev)
 337 {
 338         unsigned int hash, rii_p = 0;
 339         struct rif_cache_s *entry;
 340
 341
 342         spin_lock_bh(&rif_lock);
 343
 344         /*
 345          *      Firstly see if the entry exists
 346          */
 347
 348         if(trh->saddr[0] & TR_RII)
 349         {
 350                 trh->saddr[0]&=0x7f;
 351                 if (((ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8) > 2)
 352                 {
 353                         rii_p = 1;
 354                 }
 355         }
 356
 357         hash = rif_hash(trh->saddr);
 358         for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);entry=entry->next);
 359
 360         if(entry==NULL)
 361         {
 362 #if TR_SR_DEBUG
 363 printk("adding rif_entry: addr:%02X:%02X:%02X:%02X:%02X:%02X rcf:%04X\n",
 364                 trh->saddr[0],trh->saddr[1],trh->saddr[2],
 365                 trh->saddr[3],trh->saddr[4],trh->saddr[5],
 366                 ntohs(trh->rcf));
 367 #endif
 368                 /*
 369                  *      Allocate our new entry. A failure to allocate loses
 370                  *      use the information. This is harmless.
 371                  *
 372                  *      FIXME: We ought to keep some kind of cache size
 373                  *      limiting and adjust the timers to suit.
 374                  */
 375                 entry=kmalloc(sizeof(struct rif_cache_s),GFP_ATOMIC);
 376
 377                 if(!entry)
 378                 {
 379                         printk(KERN_DEBUG "tr.c: Couldn't malloc rif cache entry !\n");
 380                         spin_unlock_bh(&rif_lock);
 381                         return;
 382                 }
 383
 384                 memcpy(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);
 385                 entry->iface = dev->ifindex;
 386                 entry->next=rif_table[hash];
 387                 entry->last_used=jiffies;
 388                 rif_table[hash]=entry;
 389
 390                 if (rii_p)
 391                 {
 392                         entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
 393                         memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
 394                         entry->local_ring = 0;
 395                         trh->saddr[0]|=TR_RII; /* put the routing indicator back for tcpdump */
 396                 }
 397                 else
 398                 {
 399                         entry->local_ring = 1;
 400                 }
 401         }
 402         else    /* Y. Tahara added */
 403         {
 404                 /*
 405                  *      Update existing entries
 406                  */
 407                 if (!entry->local_ring)
 408                     if (entry->rcf != (trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK)) &&
 409                          !(trh->rcf & htons(TR_RCF_BROADCAST_MASK)))
 410                     {
 411 #if TR_SR_DEBUG
 412 printk("updating rif_entry: addr:%02X:%02X:%02X:%02X:%02X:%02X rcf:%04X\n",
 413                 trh->saddr[0],trh->saddr[1],trh->saddr[2],
 414                 trh->saddr[3],trh->saddr[4],trh->saddr[5],
 415                 ntohs(trh->rcf));
 416 #endif
 417                             entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
 418                             memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
 419                     }
 420                 entry->last_used=jiffies;
 421         }
 422         spin_unlock_bh(&rif_lock);
 423 }
 424
 425 /*
 426  *      Scan the cache with a timer and see what we need to throw out.
 427  */
 428
 429 static void rif_check_expire(unsigned long dummy)
 430 {
 431         int i;
 432         unsigned long next_interval = jiffies + sysctl_tr_rif_timeout/2;
 433
 434         spin_lock_bh(&rif_lock);
 435
 436         for(i =0; i < RIF_TABLE_SIZE; i++) {
 437                 struct rif_cache_s *entry, **pentry;
 438
 439                 pentry = rif_table+i;
 440                 while((entry=*pentry) != NULL) {
 441                         unsigned long expires
 442                                 = entry->last_used + sysctl_tr_rif_timeout;
 443
 444                         if (time_before_eq(expires, jiffies)) {
 445                                 *pentry = entry->next;
 446                                 kfree(entry);
 447                         } else {
 448                                 pentry = &entry->next;
 449
 450                                 if (time_before(expires, next_interval))
 451                                         next_interval = expires;
 452                         }
 453                 }
 454         }
 455
 456         spin_unlock_bh(&rif_lock);
 457
 458         mod_timer(&rif_timer, next_interval);
 459
 460 }
 461
 462 /*
 463  *      Generate the /proc/net information for the token ring RIF
 464  *      routing.
 465  */
 466
 467 #ifdef CONFIG_PROC_FS
 468
 469 static struct rif_cache_s *rif_get_idx(loff_t pos)
 470 {
 471         int i;
 472         struct rif_cache_s *entry;
 473         loff_t off = 0;
 474
 475         for(i = 0; i < RIF_TABLE_SIZE; i++)
 476                 for(entry = rif_table[i]; entry; entry = entry->next) {
 477                         if (off == pos)
 478                                 return entry;
 479                         ++off;
 480                 }
 481
 482         return NULL;
 483 }
 484
 485 static void *rif_seq_start(struct seq_file *seq, loff_t *pos)
 486 {
 487         spin_lock_bh(&rif_lock);
 488
 489         return *pos ? rif_get_idx(*pos - 1) : SEQ_START_TOKEN;
 490 }
 491
 492 static void *rif_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 493 {
 494         int i;
 495         struct rif_cache_s *ent = v;
 496
 497         ++*pos;
 498
 499         if (v == SEQ_START_TOKEN) {
 500                 i = -1;
 501                 goto scan;
 502         }
 503
 504         if (ent->next)
 505                 return ent->next;
 506
 507         i = rif_hash(ent->addr);
 508  scan:
 509         while (++i < RIF_TABLE_SIZE) {
 510                 if ((ent = rif_table[i]) != NULL)
 511                         return ent;
 512         }
 513         return NULL;
 514 }
 515
 516 static void rif_seq_stop(struct seq_file *seq, void *v)
 517 {
 518         spin_unlock_bh(&rif_lock);
 519 }
 520
 521 static int rif_seq_show(struct seq_file *seq, void *v)
 522 {
 523         int j, rcf_len, segment, brdgnmb;
 524         struct rif_cache_s *entry = v;
 525
 526         if (v == SEQ_START_TOKEN)
 527                 seq_puts(seq,
 528                      "if     TR address       TTL   rcf   routing segments\n");
 529         else {
 530                 struct net_device *dev = dev_get_by_index(entry->iface);
 531                 long ttl = (long) (entry->last_used + sysctl_tr_rif_timeout)
 532                                 - (long) jiffies;
 533
 534                 seq_printf(seq, "%s %02X:%02X:%02X:%02X:%02X:%02X %7li ",
 535                            dev?dev->name:"?",
 536                            entry->addr[0],entry->addr[1],entry->addr[2],
 537                            entry->addr[3],entry->addr[4],entry->addr[5],
 538                            ttl/HZ);
 539
 540                         if (entry->local_ring)
 541                                 seq_puts(seq, "local\n");
 542                         else {
 543
 544                                 seq_printf(seq, "%04X", ntohs(entry->rcf));
 545                                 rcf_len = ((ntohs(entry->rcf) & TR_RCF_LEN_MASK)>>8)-2;
 546                                 if (rcf_len)
 547                                         rcf_len >>= 1;
 548                                 for(j = 1; j < rcf_len; j++) {
 549                                         if(j==1) {
 550                                                 segment=ntohs(entry->rseg[j-1])>>4;
 551                                                 seq_printf(seq,"  %03X",segment);
 552                                         };
 553                                         segment=ntohs(entry->rseg[j])>>4;
 554                                         brdgnmb=ntohs(entry->rseg[j-1])&0x00f;
 555                                         seq_printf(seq,"-%01X-%03X",brdgnmb,segment);
 556                                 }
 557                                 seq_putc(seq, '\n');
 558                         }
 559                 }
 560         return 0;
 561 }
 562
 563
 564 static struct seq_operations rif_seq_ops = {
 565         .start = rif_seq_start,
 566         .next  = rif_seq_next,
 567         .stop  = rif_seq_stop,
 568         .show  = rif_seq_show,
 569 };
 570
 571 static int rif_seq_open(struct inode *inode, struct file *file)
 572 {
 573         return seq_open(file, &rif_seq_ops);
 574 }
 575
 576 static struct file_operations rif_seq_fops = {
 577         .owner   = THIS_MODULE,
 578         .open    = rif_seq_open,
 579         .read    = seq_read,
 580         .llseek  = seq_lseek,
 581         .release = seq_release,
 582 };
 583
 584 #endif
 585
 586 /*
 587  *      Called during bootup.  We don't actually have to initialise
 588  *      too much for this.
 589  */
 590
 591 static int __init rif_init(void)
 592 {
 593         init_timer(&rif_timer);
 594         rif_timer.expires  = sysctl_tr_rif_timeout;
 595         rif_timer.data     = 0L;
 596         rif_timer.function = rif_check_expire;
 597         add_timer(&rif_timer);
 598
 599         proc_net_fops_create("tr_rif", S_IRUGO, &rif_seq_fops);
 600         return 0;
 601 }
 602
 603 module_init(rif_init);
 604
 605 EXPORT_SYMBOL(tr_source_route);
 606 EXPORT_SYMBOL(tr_type_trans);