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