git.oblomov.eu Git - linux-2.6/blob - 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 <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 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 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 {
 289 DECLARE_MAC_BUF(mac);
 290 printk("source routing for %s\n",print_mac(mac, trh->daddr));
 291 }
 292 #endif
 293                         if(!entry->local_ring && (ntohs(entry->rcf) & TR_RCF_LEN_MASK) >> 8)
 294                         {
 295                                 trh->rcf=entry->rcf;
 296                                 memcpy(&trh->rseg[0],&entry->rseg[0],8*sizeof(unsigned short));
 297                                 trh->rcf^=htons(TR_RCF_DIR_BIT);
 298                                 trh->rcf&=htons(0x1fff);        /* Issam Chehab <ichehab@madge1.demon.co.uk> */
 299
 300                                 trh->saddr[0]|=TR_RII;
 301 #if TR_SR_DEBUG
 302                                 printk("entry found with rcf %04x\n", entry->rcf);
 303                         }
 304                         else
 305                         {
 306                                 printk("entry found but without rcf length, local=%02x\n", entry->local_ring);
 307 #endif
 308                         }
 309                         entry->last_used=jiffies;
 310                 }
 311                 else
 312                 {
 313                         /*
 314                          *      Without the information we simply have to shout
 315                          *      on the wire. The replies should rapidly clean this
 316                          *      situation up.
 317                          */
 318                         trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)
 319                                        | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);
 320                         trh->saddr[0]|=TR_RII;
 321 #if TR_SR_DEBUG
 322                         printk("no entry in rif table found - broadcasting frame\n");
 323 #endif
 324                 }
 325         }
 326
 327         /* Compress the RIF here so we don't have to do it in the driver(s) */
 328         if (!(trh->saddr[0] & 0x80))
 329                 slack = 18;
 330         else
 331                 slack = 18 - ((ntohs(trh->rcf) & TR_RCF_LEN_MASK)>>8);
 332         olddata = skb->data;
 333         spin_unlock_irqrestore(&rif_lock, flags);
 334
 335         skb_pull(skb, slack);
 336         memmove(skb->data, olddata, sizeof(struct trh_hdr) - slack);
 337 }
 338
 339 /*
 340  *      We have learned some new RIF information for our source
 341  *      routing.
 342  */
 343
 344 static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev)
 345 {
 346         unsigned int hash, rii_p = 0;
 347         unsigned long flags;
 348         struct rif_cache *entry;
 349         unsigned char saddr0;
 350
 351         spin_lock_irqsave(&rif_lock, flags);
 352         saddr0 = trh->saddr[0];
 353
 354         /*
 355          *      Firstly see if the entry exists
 356          */
 357
 358         if(trh->saddr[0] & TR_RII)
 359         {
 360                 trh->saddr[0]&=0x7f;
 361                 if (((ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8) > 2)
 362                 {
 363                         rii_p = 1;
 364                 }
 365         }
 366
 367         hash = rif_hash(trh->saddr);
 368         for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);entry=entry->next);
 369
 370         if(entry==NULL)
 371         {
 372 #if TR_SR_DEBUG
 373                 DECLARE_MAC_BUF(mac);
 374                 printk("adding rif_entry: addr:%s rcf:%04X\n",
 375                        print_mac(mac, trh->saddr), ntohs(trh->rcf));
 376 #endif
 377                 /*
 378                  *      Allocate our new entry. A failure to allocate loses
 379                  *      use the information. This is harmless.
 380                  *
 381                  *      FIXME: We ought to keep some kind of cache size
 382                  *      limiting and adjust the timers to suit.
 383                  */
 384                 entry=kmalloc(sizeof(struct rif_cache),GFP_ATOMIC);
 385
 386                 if(!entry)
 387                 {
 388                         printk(KERN_DEBUG "tr.c: Couldn't malloc rif cache entry !\n");
 389                         spin_unlock_irqrestore(&rif_lock, flags);
 390                         return;
 391                 }
 392
 393                 memcpy(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);
 394                 entry->iface = dev->ifindex;
 395                 entry->next=rif_table[hash];
 396                 entry->last_used=jiffies;
 397                 rif_table[hash]=entry;
 398
 399                 if (rii_p)
 400                 {
 401                         entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
 402                         memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
 403                         entry->local_ring = 0;
 404                 }
 405                 else
 406                 {
 407                         entry->local_ring = 1;
 408                 }
 409         }
 410         else    /* Y. Tahara added */
 411         {
 412                 /*
 413                  *      Update existing entries
 414                  */
 415                 if (!entry->local_ring)
 416                     if (entry->rcf != (trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK)) &&
 417                          !(trh->rcf & htons(TR_RCF_BROADCAST_MASK)))
 418                     {
 419 #if TR_SR_DEBUG
 420 {
 421 DECLARE_MAC_BUF(mac);
 422 printk("updating rif_entry: addr:%s rcf:%04X\n",
 423                 print_mac(mac, trh->saddr), ntohs(trh->rcf));
 424 }
 425 #endif
 426                             entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);
 427                             memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));
 428                     }
 429                 entry->last_used=jiffies;
 430         }
 431         trh->saddr[0]=saddr0; /* put the routing indicator back for tcpdump */
 432         spin_unlock_irqrestore(&rif_lock, flags);
 433 }
 434
 435 /*
 436  *      Scan the cache with a timer and see what we need to throw out.
 437  */
 438
 439 static void rif_check_expire(unsigned long dummy)
 440 {
 441         int i;
 442         unsigned long flags, next_interval = jiffies + sysctl_tr_rif_timeout/2;
 443
 444         spin_lock_irqsave(&rif_lock, flags);
 445
 446         for(i =0; i < RIF_TABLE_SIZE; i++) {
 447                 struct rif_cache *entry, **pentry;
 448
 449                 pentry = rif_table+i;
 450                 while((entry=*pentry) != NULL) {
 451                         unsigned long expires
 452                                 = entry->last_used + sysctl_tr_rif_timeout;
 453
 454                         if (time_before_eq(expires, jiffies)) {
 455                                 *pentry = entry->next;
 456                                 kfree(entry);
 457                         } else {
 458                                 pentry = &entry->next;
 459
 460                                 if (time_before(expires, next_interval))
 461                                         next_interval = expires;
 462                         }
 463                 }
 464         }
 465
 466         spin_unlock_irqrestore(&rif_lock, flags);
 467
 468         mod_timer(&rif_timer, next_interval);
 469
 470 }
 471
 472 /*
 473  *      Generate the /proc/net information for the token ring RIF
 474  *      routing.
 475  */
 476
 477 #ifdef CONFIG_PROC_FS
 478
 479 static struct rif_cache *rif_get_idx(loff_t pos)
 480 {
 481         int i;
 482         struct rif_cache *entry;
 483         loff_t off = 0;
 484
 485         for(i = 0; i < RIF_TABLE_SIZE; i++)
 486                 for(entry = rif_table[i]; entry; entry = entry->next) {
 487                         if (off == pos)
 488                                 return entry;
 489                         ++off;
 490                 }
 491
 492         return NULL;
 493 }
 494
 495 static void *rif_seq_start(struct seq_file *seq, loff_t *pos)
 496 {
 497         spin_lock_irq(&rif_lock);
 498
 499         return *pos ? rif_get_idx(*pos - 1) : SEQ_START_TOKEN;
 500 }
 501
 502 static void *rif_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 503 {
 504         int i;
 505         struct rif_cache *ent = v;
 506
 507         ++*pos;
 508
 509         if (v == SEQ_START_TOKEN) {
 510                 i = -1;
 511                 goto scan;
 512         }
 513
 514         if (ent->next)
 515                 return ent->next;
 516
 517         i = rif_hash(ent->addr);
 518  scan:
 519         while (++i < RIF_TABLE_SIZE) {
 520                 if ((ent = rif_table[i]) != NULL)
 521                         return ent;
 522         }
 523         return NULL;
 524 }
 525
 526 static void rif_seq_stop(struct seq_file *seq, void *v)
 527 {
 528         spin_unlock_irq(&rif_lock);
 529 }
 530
 531 static int rif_seq_show(struct seq_file *seq, void *v)
 532 {
 533         int j, rcf_len, segment, brdgnmb;
 534         struct rif_cache *entry = v;
 535         DECLARE_MAC_BUF(mac);
 536
 537         if (v == SEQ_START_TOKEN)
 538                 seq_puts(seq,
 539                      "if     TR address       TTL   rcf   routing segments\n");
 540         else {
 541                 struct net_device *dev = dev_get_by_index(&init_net, entry->iface);
 542                 long ttl = (long) (entry->last_used + sysctl_tr_rif_timeout)
 543                                 - (long) jiffies;
 544
 545                 seq_printf(seq, "%s %s %7li ",
 546                            dev?dev->name:"?",
 547                            print_mac(mac, entry->addr),
 548                            ttl/HZ);
 549
 550                         if (entry->local_ring)
 551                                 seq_puts(seq, "local\n");
 552                         else {
 553
 554                                 seq_printf(seq, "%04X", ntohs(entry->rcf));
 555                                 rcf_len = ((ntohs(entry->rcf) & TR_RCF_LEN_MASK)>>8)-2;
 556                                 if (rcf_len)
 557                                         rcf_len >>= 1;
 558                                 for(j = 1; j < rcf_len; j++) {
 559                                         if(j==1) {
 560                                                 segment=ntohs(entry->rseg[j-1])>>4;
 561                                                 seq_printf(seq,"  %03X",segment);
 562                                         }
 563
 564                                         segment=ntohs(entry->rseg[j])>>4;
 565                                         brdgnmb=ntohs(entry->rseg[j-1])&0x00f;
 566                                         seq_printf(seq,"-%01X-%03X",brdgnmb,segment);
 567                                 }
 568                                 seq_putc(seq, '\n');
 569                         }
 570                 }
 571         return 0;
 572 }
 573
 574
 575 static const struct seq_operations rif_seq_ops = {
 576         .start = rif_seq_start,
 577         .next  = rif_seq_next,
 578         .stop  = rif_seq_stop,
 579         .show  = rif_seq_show,
 580 };
 581
 582 static int rif_seq_open(struct inode *inode, struct file *file)
 583 {
 584         return seq_open(file, &rif_seq_ops);
 585 }
 586
 587 static const struct file_operations rif_seq_fops = {
 588         .owner   = THIS_MODULE,
 589         .open    = rif_seq_open,
 590         .read    = seq_read,
 591         .llseek  = seq_lseek,
 592         .release = seq_release,
 593 };
 594
 595 #endif
 596
 597 static const struct header_ops tr_header_ops = {
 598         .create = tr_header,
 599         .rebuild= tr_rebuild_header,
 600 };
 601
 602 static void tr_setup(struct net_device *dev)
 603 {
 604         /*
 605          *      Configure and register
 606          */
 607
 608         dev->header_ops = &tr_header_ops;
 609
 610         dev->type               = ARPHRD_IEEE802_TR;
 611         dev->hard_header_len    = TR_HLEN;
 612         dev->mtu                = 2000;
 613         dev->addr_len           = TR_ALEN;
 614         dev->tx_queue_len       = 100;  /* Long queues on tr */
 615
 616         memset(dev->broadcast,0xFF, TR_ALEN);
 617
 618         /* New-style flags. */
 619         dev->flags              = IFF_BROADCAST | IFF_MULTICAST ;
 620 }
 621
 622 /**
 623  * alloc_trdev - Register token ring device
 624  * @sizeof_priv: Size of additional driver-private structure to be allocated
 625  *      for this token ring device
 626  *
 627  * Fill in the fields of the device structure with token ring-generic values.
 628  *
 629  * Constructs a new net device, complete with a private data area of
 630  * size @sizeof_priv.  A 32-byte (not bit) alignment is enforced for
 631  * this private data area.
 632  */
 633 struct net_device *alloc_trdev(int sizeof_priv)
 634 {
 635         return alloc_netdev(sizeof_priv, "tr%d", tr_setup);
 636 }
 637
 638 #ifdef CONFIG_SYSCTL
 639 static struct ctl_table tr_table[] = {
 640         {
 641                 .ctl_name       = NET_TR_RIF_TIMEOUT,
 642                 .procname       = "rif_timeout",
 643                 .data           = &sysctl_tr_rif_timeout,
 644                 .maxlen         = sizeof(int),
 645                 .mode           = 0644,
 646                 .proc_handler   = &proc_dointvec
 647         },
 648         { 0 },
 649 };
 650
 651 static __initdata struct ctl_path tr_path[] = {
 652         { .procname = "net", .ctl_name = CTL_NET, },
 653         { .procname = "token-ring", .ctl_name = NET_TR, },
 654         { }
 655 };
 656 #endif
 657
 658 /*
 659  *      Called during bootup.  We don't actually have to initialise
 660  *      too much for this.
 661  */
 662
 663 static int __init rif_init(void)
 664 {
 665         rif_timer.expires  = jiffies + sysctl_tr_rif_timeout;
 666         setup_timer(&rif_timer, rif_check_expire, 0);
 667         add_timer(&rif_timer);
 668 #ifdef CONFIG_SYSCTL
 669         register_sysctl_paths(tr_path, tr_table);
 670 #endif
 671         proc_net_fops_create(&init_net, "tr_rif", S_IRUGO, &rif_seq_fops);
 672         return 0;
 673 }
 674
 675 module_init(rif_init);
 676
 677 EXPORT_SYMBOL(tr_type_trans);
 678 EXPORT_SYMBOL(alloc_trdev);