net/appletalk/aarp.c

   1 /*
   2  *      AARP:           An implementation of the AppleTalk AARP protocol for
   3  *                      Ethernet 'ELAP'.
   4  *
   5  *              Alan Cox  <Alan.Cox@linux.org>
   6  *
   7  *      This doesn't fit cleanly with the IP arp. Potentially we can use
   8  *      the generic neighbour discovery code to clean this up.
   9  *
  10  *      FIXME:
  11  *              We ought to handle the retransmits with a single list and a
  12  *      separate fast timer for when it is needed.
  13  *              Use neighbour discovery code.
  14  *              Token Ring Support.
  15  *
  16  *              This program is free software; you can redistribute it and/or
  17  *              modify it under the terms of the GNU General Public License
  18  *              as published by the Free Software Foundation; either version
  19  *              2 of the License, or (at your option) any later version.
  20  *
  21  *
  22  *      References:
  23  *              Inside AppleTalk (2nd Ed).
  24  *      Fixes:
  25  *              Jaume Grau      -       flush caches on AARP_PROBE
  26  *              Rob Newberry    -       Added proxy AARP and AARP proc fs,
  27  *                                      moved probing from DDP module.
  28  *              Arnaldo C. Melo -       don't mangle rx packets
  29  *
  30  */
  31
  32 #include <linux/config.h>
  33 #if defined(CONFIG_ATALK) || defined(CONFIG_ATALK_MODULE)
  34 #include <asm/uaccess.h>
  35 #include <asm/system.h>
  36 #include <asm/bitops.h>
  37 #include <linux/types.h>
  38 #include <linux/kernel.h>
  39 #include <linux/sched.h>
  40 #include <linux/string.h>
  41 #include <linux/mm.h>
  42 #include <linux/socket.h>
  43 #include <linux/sockios.h>
  44 #include <linux/in.h>
  45 #include <linux/errno.h>
  46 #include <linux/interrupt.h>
  47 #include <linux/if_ether.h>
  48 #include <linux/inet.h>
  49 #include <linux/notifier.h>
  50 #include <linux/netdevice.h>
  51 #include <linux/etherdevice.h>
  52 #include <linux/if_arp.h>
  53 #include <linux/skbuff.h>
  54 #include <linux/spinlock.h>
  55 #include <net/sock.h>
  56 #include <net/datalink.h>
  57 #include <net/psnap.h>
  58 #include <linux/atalk.h>
  59 #include <linux/init.h>
  60 #include <linux/proc_fs.h>
  61 #include <linux/module.h>
  62
  63 int sysctl_aarp_expiry_time = AARP_EXPIRY_TIME;
  64 int sysctl_aarp_tick_time = AARP_TICK_TIME;
  65 int sysctl_aarp_retransmit_limit = AARP_RETRANSMIT_LIMIT;
  66 int sysctl_aarp_resolve_time = AARP_RESOLVE_TIME;
  67
  68 /* Lists of aarp entries */
  69 struct aarp_entry {
  70         /* These first two are only used for unresolved entries */
  71         unsigned long last_sent;                /* Last time we xmitted the aarp request */
  72         struct sk_buff_head packet_queue;       /* Queue of frames wait for resolution */
  73         int status;                             /* Used for proxy AARP */
  74         unsigned long expires_at;               /* Entry expiry time */
  75         struct at_addr target_addr;             /* DDP Address */
  76         struct net_device *dev;                 /* Device to use */
  77         char hwaddr[6];                         /* Physical i/f address of target/router */
  78         unsigned short xmit_count;              /* When this hits 10 we give up */
  79         struct aarp_entry *next;                /* Next entry in chain */
  80 };
  81
  82 /* Hashed list of resolved, unresolved and proxy entries */
  83 static struct aarp_entry *resolved[AARP_HASH_SIZE];
  84 static struct aarp_entry *unresolved[AARP_HASH_SIZE];
  85 static struct aarp_entry *proxies[AARP_HASH_SIZE];
  86 static int unresolved_count;
  87
  88 /* One lock protects it all. */
  89 static spinlock_t aarp_lock = SPIN_LOCK_UNLOCKED;
  90
  91 /* Used to walk the list and purge/kick entries.  */
  92 static struct timer_list aarp_timer;
  93
  94 /*
  95  *      Delete an aarp queue
  96  *
  97  *      Must run under aarp_lock.
  98  */
  99 static void __aarp_expire(struct aarp_entry *a)
 100 {
 101         skb_queue_purge(&a->packet_queue);
 102         kfree(a);
 103 }
 104
 105 /*
 106  *      Send an aarp queue entry request
 107  *
 108  *      Must run under aarp_lock.
 109  */
 110
 111 static void __aarp_send_query(struct aarp_entry *a)
 112 {
 113         static char aarp_eth_multicast[ETH_ALEN] =
 114                 { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF };
 115         struct net_device *dev = a->dev;
 116         int len = dev->hard_header_len + sizeof(struct elapaarp) +
 117                 aarp_dl->header_length;
 118         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 119         struct at_addr *sat = atalk_find_dev_addr(dev);
 120         struct elapaarp *eah;
 121
 122         if (!skb)
 123                 return;
 124
 125         if (!sat) {
 126                 kfree_skb(skb);
 127                 return;
 128         }
 129
 130         /* Set up the buffer */
 131         skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length);
 132         eah             =       (struct elapaarp *)skb_put(skb,
 133                                                 sizeof(struct elapaarp));
 134         skb->protocol   =       htons(ETH_P_ATALK);
 135         skb->nh.raw     =       skb->h.raw = (void *) eah;
 136         skb->dev        =       dev;
 137
 138         /* Set up the ARP */
 139         eah->hw_type    =       htons(AARP_HW_TYPE_ETHERNET);
 140         eah->pa_type    =       htons(ETH_P_ATALK);
 141         eah->hw_len     =       ETH_ALEN;
 142         eah->pa_len     =       AARP_PA_ALEN;
 143         eah->function   =       htons(AARP_REQUEST);
 144
 145         memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN);
 146
 147         eah->pa_src_zero=       0;
 148         eah->pa_src_net =       sat->s_net;
 149         eah->pa_src_node=       sat->s_node;
 150
 151         memset(eah->hw_dst, '\0', ETH_ALEN);
 152
 153         eah->pa_dst_zero=       0;
 154         eah->pa_dst_net =       a->target_addr.s_net;
 155         eah->pa_dst_node=       a->target_addr.s_node;
 156
 157         /* Add ELAP headers and set target to the AARP multicast */
 158         aarp_dl->datalink_header(aarp_dl, skb, aarp_eth_multicast);
 159
 160         /* Send it */
 161         dev_queue_xmit(skb);
 162         /* Update the sending count */
 163         a->xmit_count++;
 164 }
 165
 166 /* This runs under aarp_lock and in softint context, so only atomic memory
 167  * allocations can be used. */
 168 static void aarp_send_reply(struct net_device *dev, struct at_addr *us,
 169                             struct at_addr *them, unsigned char *sha)
 170 {
 171         int len = dev->hard_header_len + sizeof(struct elapaarp) +
 172                         aarp_dl->header_length;
 173         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 174         struct elapaarp *eah;
 175
 176         if (!skb)
 177                 return;
 178
 179         /* Set up the buffer */
 180         skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length);
 181         eah             =       (struct elapaarp *)skb_put(skb,
 182                                         sizeof(struct elapaarp));
 183         skb->protocol   =       htons(ETH_P_ATALK);
 184         skb->nh.raw     =       skb->h.raw = (void *) eah;
 185         skb->dev        =       dev;
 186
 187         /* Set up the ARP */
 188         eah->hw_type    =       htons(AARP_HW_TYPE_ETHERNET);
 189         eah->pa_type    =       htons(ETH_P_ATALK);
 190         eah->hw_len     =       ETH_ALEN;
 191         eah->pa_len     =       AARP_PA_ALEN;
 192         eah->function   =       htons(AARP_REPLY);
 193
 194         memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN);
 195
 196         eah->pa_src_zero=       0;
 197         eah->pa_src_net =       us->s_net;
 198         eah->pa_src_node=       us->s_node;
 199
 200         if (!sha)
 201                 memset(eah->hw_dst, '\0', ETH_ALEN);
 202         else
 203                 memcpy(eah->hw_dst, sha, ETH_ALEN);
 204
 205         eah->pa_dst_zero=       0;
 206         eah->pa_dst_net =       them->s_net;
 207         eah->pa_dst_node=       them->s_node;
 208
 209         /* Add ELAP headers and set target to the AARP multicast */
 210         aarp_dl->datalink_header(aarp_dl, skb, sha);
 211         /* Send it */
 212         dev_queue_xmit(skb);
 213 }
 214
 215 /*
 216  *      Send probe frames. Called from aarp_probe_network and
 217  *      aarp_proxy_probe_network.
 218  */
 219
 220 void aarp_send_probe(struct net_device *dev, struct at_addr *us)
 221 {
 222         int len = dev->hard_header_len + sizeof(struct elapaarp) +
 223                         aarp_dl->header_length;
 224         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 225         static char aarp_eth_multicast[ETH_ALEN] =
 226                 { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF };
 227         struct elapaarp *eah;
 228
 229         if (!skb)
 230                 return;
 231
 232         /* Set up the buffer */
 233         skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length);
 234         eah             =       (struct elapaarp *)skb_put(skb,
 235                                         sizeof(struct elapaarp));
 236         skb->protocol   =       htons(ETH_P_ATALK);
 237         skb->nh.raw     =       skb->h.raw = (void *) eah;
 238         skb->dev        =       dev;
 239
 240         /* Set up the ARP */
 241         eah->hw_type    =       htons(AARP_HW_TYPE_ETHERNET);
 242         eah->pa_type    =       htons(ETH_P_ATALK);
 243         eah->hw_len     =       ETH_ALEN;
 244         eah->pa_len     =       AARP_PA_ALEN;
 245         eah->function   =       htons(AARP_PROBE);
 246
 247         memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN);
 248
 249         eah->pa_src_zero=       0;
 250         eah->pa_src_net =       us->s_net;
 251         eah->pa_src_node=       us->s_node;
 252
 253         memset(eah->hw_dst, '\0', ETH_ALEN);
 254
 255         eah->pa_dst_zero=       0;
 256         eah->pa_dst_net =       us->s_net;
 257         eah->pa_dst_node=       us->s_node;
 258
 259         /* Add ELAP headers and set target to the AARP multicast */
 260         aarp_dl->datalink_header(aarp_dl, skb, aarp_eth_multicast);
 261         /* Send it */
 262         dev_queue_xmit(skb);
 263 }
 264
 265 /*
 266  *      Handle an aarp timer expire
 267  *
 268  *      Must run under the aarp_lock.
 269  */
 270
 271 static void __aarp_expire_timer(struct aarp_entry **n)
 272 {
 273         struct aarp_entry *t;
 274
 275         while (*n)
 276                 /* Expired ? */
 277                 if (time_after(jiffies, (*n)->expires_at)) {
 278                         t = *n;
 279                         *n = (*n)->next;
 280                         __aarp_expire(t);
 281                 } else
 282                         n = &((*n)->next);
 283 }
 284
 285 /*
 286  *      Kick all pending requests 5 times a second.
 287  *
 288  *      Must run under the aarp_lock.
 289  */
 290
 291 static void __aarp_kick(struct aarp_entry **n)
 292 {
 293         struct aarp_entry *t;
 294
 295         while (*n)
 296                 /* Expired: if this will be the 11th tx, we delete instead. */
 297                 if ((*n)->xmit_count >= sysctl_aarp_retransmit_limit) {
 298                         t = *n;
 299                         *n = (*n)->next;
 300                         __aarp_expire(t);
 301                 } else {
 302                         __aarp_send_query(*n);
 303                         n = &((*n)->next);
 304                 }
 305 }
 306
 307 /*
 308  *      A device has gone down. Take all entries referring to the device
 309  *      and remove them.
 310  *
 311  *      Must run under the aarp_lock.
 312  */
 313
 314 static void __aarp_expire_device(struct aarp_entry **n, struct net_device *dev)
 315 {
 316         struct aarp_entry *t;
 317
 318         while (*n)
 319                 if ((*n)->dev == dev) {
 320                         t = *n;
 321                         *n = (*n)->next;
 322                         __aarp_expire(t);
 323                 } else
 324                         n = &((*n)->next);
 325 }
 326
 327 /* Handle the timer event */
 328 static void aarp_expire_timeout(unsigned long unused)
 329 {
 330         int ct;
 331
 332         spin_lock_bh(&aarp_lock);
 333
 334         for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 335                 __aarp_expire_timer(&resolved[ct]);
 336                 __aarp_kick(&unresolved[ct]);
 337                 __aarp_expire_timer(&unresolved[ct]);
 338                 __aarp_expire_timer(&proxies[ct]);
 339         }
 340
 341         spin_unlock_bh(&aarp_lock);
 342         mod_timer(&aarp_timer, jiffies +
 343                   (unresolved_count ? sysctl_aarp_tick_time :
 344                    sysctl_aarp_expiry_time));
 345 }
 346
 347 /* Network device notifier chain handler. */
 348 static int aarp_device_event(struct notifier_block *this, unsigned long event,
 349                                 void *ptr)
 350 {
 351         int ct;
 352
 353         if (event == NETDEV_DOWN) {
 354                 spin_lock_bh(&aarp_lock);
 355
 356                 for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 357                         __aarp_expire_device(&resolved[ct], ptr);
 358                         __aarp_expire_device(&unresolved[ct], ptr);
 359                         __aarp_expire_device(&proxies[ct], ptr);
 360                 }
 361
 362                 spin_unlock_bh(&aarp_lock);
 363         }
 364         return NOTIFY_DONE;
 365 }
 366
 367 /*
 368  *      Create a new aarp entry.  This must use GFP_ATOMIC because it
 369  *      runs while holding spinlocks.
 370  */
 371
 372 static struct aarp_entry *aarp_alloc(void)
 373 {
 374         struct aarp_entry *a = kmalloc(sizeof(struct aarp_entry), GFP_ATOMIC);
 375
 376         if (a)
 377                 skb_queue_head_init(&a->packet_queue);
 378         return a;
 379 }
 380
 381 /*
 382  * Find an entry. We might return an expired but not yet purged entry. We
 383  * don't care as it will do no harm.
 384  *
 385  * This must run under the aarp_lock.
 386  */
 387 static struct aarp_entry *__aarp_find_entry(struct aarp_entry *list,
 388                                             struct net_device *dev,
 389                                             struct at_addr *sat)
 390 {
 391         while (list) {
 392                 if (list->target_addr.s_net == sat->s_net &&
 393                     list->target_addr.s_node == sat->s_node &&
 394                     list->dev == dev)
 395                         break;
 396                 list = list->next;
 397         }
 398
 399         return list;
 400 }
 401
 402 /* Called from the DDP code, and thus must be exported. */
 403 void aarp_proxy_remove(struct net_device *dev, struct at_addr *sa)
 404 {
 405         int hash = sa->s_node % (AARP_HASH_SIZE - 1);
 406         struct aarp_entry *a;
 407
 408         spin_lock_bh(&aarp_lock);
 409
 410         a = __aarp_find_entry(proxies[hash], dev, sa);
 411         if (a)
 412                 a->expires_at = jiffies - 1;
 413
 414         spin_unlock_bh(&aarp_lock);
 415 }
 416
 417 /* This must run under aarp_lock. */
 418 static struct at_addr *__aarp_proxy_find(struct net_device *dev,
 419                                          struct at_addr *sa)
 420 {
 421         int hash = sa->s_node % (AARP_HASH_SIZE - 1);
 422         struct aarp_entry *a = __aarp_find_entry(proxies[hash], dev, sa);
 423
 424         return a ? sa : NULL;
 425 }
 426
 427 /*
 428  * Probe a Phase 1 device or a device that requires its Net:Node to
 429  * be set via an ioctl.
 430  */
 431 void aarp_send_probe_phase1(struct atalk_iface *iface)
 432 {
 433     struct ifreq atreq;
 434     struct sockaddr_at *sa = (struct sockaddr_at *)&atreq.ifr_addr;
 435
 436     sa->sat_addr.s_node = iface->address.s_node;
 437     sa->sat_addr.s_net = ntohs(iface->address.s_net);
 438
 439     /* We pass the Net:Node to the drivers/cards by a Device ioctl. */
 440     if (!(iface->dev->do_ioctl(iface->dev, &atreq, SIOCSIFADDR))) {
 441             (void)iface->dev->do_ioctl(iface->dev, &atreq, SIOCGIFADDR);
 442             if (iface->address.s_net != htons(sa->sat_addr.s_net) ||
 443                 iface->address.s_node != sa->sat_addr.s_node)
 444                     iface->status |= ATIF_PROBE_FAIL;
 445
 446             iface->address.s_net  = htons(sa->sat_addr.s_net);
 447             iface->address.s_node = sa->sat_addr.s_node;
 448     }
 449 }
 450
 451
 452 void aarp_probe_network(struct atalk_iface *atif)
 453 {
 454         if (atif->dev->type == ARPHRD_LOCALTLK ||
 455             atif->dev->type == ARPHRD_PPP)
 456                 aarp_send_probe_phase1(atif);
 457         else {
 458                 unsigned int count;
 459
 460                 for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) {
 461                         aarp_send_probe(atif->dev, &atif->address);
 462
 463                         /* Defer 1/10th */
 464                         current->state = TASK_INTERRUPTIBLE;
 465                         schedule_timeout(HZ/10);
 466
 467                         if (atif->status & ATIF_PROBE_FAIL)
 468                                 break;
 469                 }
 470         }
 471 }
 472
 473 int aarp_proxy_probe_network(struct atalk_iface *atif, struct at_addr *sa)
 474 {
 475         int hash, retval = 1;
 476         struct aarp_entry *entry;
 477         unsigned int count;
 478
 479         /*
 480          * we don't currently support LocalTalk or PPP for proxy AARP;
 481          * if someone wants to try and add it, have fun
 482          */
 483         if (atif->dev->type == ARPHRD_LOCALTLK)
 484                 return -EPROTONOSUPPORT;
 485
 486         if (atif->dev->type == ARPHRD_PPP)
 487                 return -EPROTONOSUPPORT;
 488
 489         /*
 490          * create a new AARP entry with the flags set to be published --
 491          * we need this one to hang around even if it's in use
 492          */
 493         entry = aarp_alloc();
 494         if (!entry)
 495                 return -ENOMEM;
 496
 497         entry->expires_at = -1;
 498         entry->status = ATIF_PROBE;
 499         entry->target_addr.s_node = sa->s_node;
 500         entry->target_addr.s_net = sa->s_net;
 501         entry->dev = atif->dev;
 502
 503         spin_lock_bh(&aarp_lock);
 504
 505         hash = sa->s_node % (AARP_HASH_SIZE - 1);
 506         entry->next = proxies[hash];
 507         proxies[hash] = entry;
 508
 509         for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) {
 510                 aarp_send_probe(atif->dev, sa);
 511
 512                 /* Defer 1/10th */
 513                 current->state = TASK_INTERRUPTIBLE;
 514                 spin_unlock_bh(&aarp_lock);
 515                 schedule_timeout(HZ/10);
 516                 spin_lock_bh(&aarp_lock);
 517
 518                 if (entry->status & ATIF_PROBE_FAIL)
 519                         break;
 520         }
 521
 522         if (entry->status & ATIF_PROBE_FAIL) {
 523                 entry->expires_at = jiffies - 1; /* free the entry */
 524                 retval = -EADDRINUSE; /* return network full */
 525         } else /* clear the probing flag */
 526                 entry->status &= ~ATIF_PROBE;
 527
 528         spin_unlock_bh(&aarp_lock);
 529         return retval;
 530 }
 531
 532 /* Send a DDP frame */
 533 int aarp_send_ddp(struct net_device *dev,struct sk_buff *skb,
 534                         struct at_addr *sa, void *hwaddr)
 535 {
 536         static char ddp_eth_multicast[ETH_ALEN] =
 537                 { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF };
 538         int hash;
 539         struct aarp_entry *a;
 540
 541         skb->nh.raw = skb->data;
 542
 543         /* Check for LocalTalk first */
 544         if (dev->type == ARPHRD_LOCALTLK) {
 545                 struct at_addr *at = atalk_find_dev_addr(dev);
 546                 struct ddpehdr *ddp = (struct ddpehdr *)skb->data;
 547                 int ft = 2;
 548
 549                 /*
 550                  *      Compressible ?
 551                  *
 552                  *      IFF: src_net==dest_net==device_net
 553                  *      (zero matches anything)
 554                  */
 555
 556                 if ((!ddp->deh_snet || at->s_net == ddp->deh_snet) &&
 557                     (!ddp->deh_dnet || at->s_net == ddp->deh_dnet)) {
 558                         skb_pull(skb, sizeof(struct ddpehdr) - 4);
 559
 560                         /*
 561                          *      The upper two remaining bytes are the port
 562                          *      numbers we just happen to need. Now put the
 563                          *      length in the lower two.
 564                          */
 565                         *((__u16 *)skb->data) = htons(skb->len);
 566                         ft = 1;
 567                 }
 568                 /*
 569                  *      Nice and easy. No AARP type protocols occur here
 570                  *      so we can just shovel it out with a 3 byte LLAP header
 571                  */
 572
 573                 skb_push(skb, 3);
 574                 skb->data[0] = sa->s_node;
 575                 skb->data[1] = at->s_node;
 576                 skb->data[2] = ft;
 577                 skb->dev = dev;
 578                 goto sendit;
 579         }
 580
 581         /* On a PPP link we neither compress nor aarp.  */
 582         if (dev->type == ARPHRD_PPP) {
 583                 skb->protocol = htons(ETH_P_PPPTALK);
 584                 skb->dev = dev;
 585                 goto sendit;
 586         }
 587
 588         /* Non ELAP we cannot do. */
 589         if (dev->type != ARPHRD_ETHER)
 590                 return -1;
 591
 592         skb->dev = dev;
 593         skb->protocol = htons(ETH_P_ATALK);
 594         hash = sa->s_node % (AARP_HASH_SIZE - 1);
 595
 596         /* Do we have a resolved entry? */
 597         if (sa->s_node == ATADDR_BCAST) {
 598                 ddp_dl->datalink_header(ddp_dl, skb, ddp_eth_multicast);
 599                 goto sendit;
 600         }
 601
 602         spin_lock_bh(&aarp_lock);
 603         a = __aarp_find_entry(resolved[hash], dev, sa);
 604
 605         if (a) { /* Return 1 and fill in the address */
 606                 a->expires_at = jiffies + (sysctl_aarp_expiry_time * 10);
 607                 ddp_dl->datalink_header(ddp_dl, skb, a->hwaddr);
 608                 spin_unlock_bh(&aarp_lock);
 609                 goto sendit;
 610         }
 611
 612         /* Do we have an unresolved entry: This is the less common path */
 613         a = __aarp_find_entry(unresolved[hash], dev, sa);
 614         if (a) { /* Queue onto the unresolved queue */
 615                 skb_queue_tail(&a->packet_queue, skb);
 616                 spin_unlock_bh(&aarp_lock);
 617                 return 0;
 618         }
 619
 620         /* Allocate a new entry */
 621         a = aarp_alloc();
 622         if (!a) {
 623                 /* Whoops slipped... good job it's an unreliable protocol 8) */
 624                 spin_unlock_bh(&aarp_lock);
 625                 return -1;
 626         }
 627
 628         /* Set up the queue */
 629         skb_queue_tail(&a->packet_queue, skb);
 630         a->expires_at = jiffies + sysctl_aarp_resolve_time;
 631         a->dev = dev;
 632         a->next = unresolved[hash];
 633         a->target_addr = *sa;
 634         a->xmit_count = 0;
 635         unresolved[hash] = a;
 636         unresolved_count++;
 637
 638         /* Send an initial request for the address */
 639         __aarp_send_query(a);
 640
 641         /*
 642          *      Switch to fast timer if needed (That is if this is the
 643          *      first unresolved entry to get added)
 644          */
 645
 646         if (unresolved_count == 1)
 647                 mod_timer(&aarp_timer, jiffies + sysctl_aarp_tick_time);
 648
 649         /* Now finally, it is safe to drop the lock. */
 650         spin_unlock_bh(&aarp_lock);
 651
 652         /* Tell the ddp layer we have taken over for this frame. */
 653         return 0;
 654
 655 sendit: if (skb->sk)
 656                 skb->priority = skb->sk->priority;
 657         dev_queue_xmit(skb);
 658         return 1;
 659 }
 660
 661 /*
 662  *      An entry in the aarp unresolved queue has become resolved. Send
 663  *      all the frames queued under it.
 664  *
 665  *      Must run under aarp_lock.
 666  */
 667 static void __aarp_resolved(struct aarp_entry **list, struct aarp_entry *a,
 668                                 int hash)
 669 {
 670         struct sk_buff *skb;
 671
 672         while (*list)
 673                 if (*list == a) {
 674                         unresolved_count--;
 675                         *list = a->next;
 676
 677                         /* Move into the resolved list */
 678                         a->next = resolved[hash];
 679                         resolved[hash] = a;
 680
 681                         /* Kick frames off */
 682                         while ((skb = skb_dequeue(&a->packet_queue)) != NULL) {
 683                                 a->expires_at = jiffies +
 684                                                 sysctl_aarp_expiry_time * 10;
 685                                 ddp_dl->datalink_header(ddp_dl, skb, a->hwaddr);
 686                                 if (skb->sk)
 687                                         skb->priority = skb->sk->priority;
 688                                 dev_queue_xmit(skb);
 689                         }
 690                 } else
 691                         list = &((*list)->next);
 692 }
 693
 694 /*
 695  *      This is called by the SNAP driver whenever we see an AARP SNAP
 696  *      frame. We currently only support Ethernet.
 697  */
 698 static int aarp_rcv(struct sk_buff *skb, struct net_device *dev,
 699                         struct packet_type *pt)
 700 {
 701         struct elapaarp *ea = (struct elapaarp *)skb->h.raw;
 702         int hash, ret = 0;
 703         __u16 function;
 704         struct aarp_entry *a;
 705         struct at_addr sa, *ma, da;
 706         struct atalk_iface *ifa;
 707
 708         /* We only do Ethernet SNAP AARP. */
 709         if (dev->type != ARPHRD_ETHER)
 710                 goto out0;
 711
 712         /* Frame size ok? */
 713         if (!skb_pull(skb, sizeof(*ea)))
 714                 goto out0;
 715
 716         function = ntohs(ea->function);
 717
 718         /* Sanity check fields. */
 719         if (function < AARP_REQUEST || function > AARP_PROBE ||
 720             ea->hw_len != ETH_ALEN || ea->pa_len != AARP_PA_ALEN ||
 721             ea->pa_src_zero || ea->pa_dst_zero)
 722                 goto out0;
 723
 724         /* Looks good. */
 725         hash = ea->pa_src_node % (AARP_HASH_SIZE - 1);
 726
 727         /* Build an address. */
 728         sa.s_node = ea->pa_src_node;
 729         sa.s_net = ea->pa_src_net;
 730
 731         /* Process the packet. Check for replies of me. */
 732         ifa = atalk_find_dev(dev);
 733         if (!ifa)
 734                 goto out1;
 735
 736         if (ifa->status & ATIF_PROBE &&
 737             ifa->address.s_node == ea->pa_dst_node &&
 738             ifa->address.s_net == ea->pa_dst_net) {
 739                 ifa->status |= ATIF_PROBE_FAIL; /* Fail the probe (in use) */
 740                 goto out1;
 741         }
 742
 743         /* Check for replies of proxy AARP entries */
 744         da.s_node = ea->pa_dst_node;
 745         da.s_net = ea->pa_dst_net;
 746
 747         spin_lock_bh(&aarp_lock);
 748         a = __aarp_find_entry(proxies[hash], dev, &da);
 749
 750         if (a && a->status & ATIF_PROBE) {
 751                 a->status |= ATIF_PROBE_FAIL;
 752                 /*
 753                  * we do not respond to probe or request packets for
 754                  * this address while we are probing this address
 755                  */
 756                 goto unlock;
 757         }
 758
 759         switch (function) {
 760                 case AARP_REPLY:
 761                         if (!unresolved_count)  /* Speed up */
 762                                 break;
 763
 764                         /* Find the entry.  */
 765                         a = __aarp_find_entry(unresolved[hash],dev,&sa);
 766                         if (!a || dev != a->dev)
 767                                 break;
 768
 769                         /* We can fill one in - this is good. */
 770                         memcpy(a->hwaddr,ea->hw_src,ETH_ALEN);
 771                         __aarp_resolved(&unresolved[hash],a,hash);
 772                         if (!unresolved_count)
 773                                 mod_timer(&aarp_timer,
 774                                           jiffies + sysctl_aarp_expiry_time);
 775                         break;
 776
 777                 case AARP_REQUEST:
 778                 case AARP_PROBE:
 779                         /*
 780                          *      If it is my address set ma to my address and
 781                          *      reply. We can treat probe and request the
 782                          *      same. Probe simply means we shouldn't cache
 783                          *      the querying host, as in a probe they are
 784                          *      proposing an address not using one.
 785                          *
 786                          *      Support for proxy-AARP added. We check if the
 787                          *      address is one of our proxies before we toss
 788                          *      the packet out.
 789                          */
 790
 791                         sa.s_node = ea->pa_dst_node;
 792                         sa.s_net = ea->pa_dst_net;
 793
 794                         /* See if we have a matching proxy. */
 795                         ma = __aarp_proxy_find(dev, &sa);
 796                         if (!ma)
 797                                 ma = &ifa->address;
 798                         else { /* We need to make a copy of the entry. */
 799                                 da.s_node = sa.s_node;
 800                                 da.s_net = da.s_net;
 801                                 ma = &da;
 802                         }
 803
 804                         if (function == AARP_PROBE) {
 805                                 /* A probe implies someone trying to get an
 806                                  * address. So as a precaution flush any
 807                                  * entries we have for this address. */
 808                                 struct aarp_entry *a = __aarp_find_entry(
 809                                         resolved[sa.s_node%(AARP_HASH_SIZE-1)],
 810                                         skb->dev, &sa);
 811                                 /* Make it expire next tick - that avoids us
 812                                  * getting into a probe/flush/learn/probe/
 813                                  * flush/learn cycle during probing of a slow
 814                                  * to respond host addr. */
 815                                 if (a) {
 816                                         a->expires_at = jiffies - 1;
 817                                         mod_timer(&aarp_timer, jiffies +
 818                                                         sysctl_aarp_tick_time);
 819                                 }
 820                         }
 821
 822                         if (sa.s_node != ma->s_node)
 823                                 break;
 824
 825                         if (sa.s_net && ma->s_net && sa.s_net != ma->s_net)
 826                                 break;
 827
 828                         sa.s_node = ea->pa_src_node;
 829                         sa.s_net = ea->pa_src_net;
 830
 831                         /* aarp_my_address has found the address to use for us.
 832                         */
 833                         aarp_send_reply(dev, ma, &sa, ea->hw_src);
 834                         break;
 835         }
 836
 837 unlock: spin_unlock_bh(&aarp_lock);
 838 out1:   ret = 1;
 839 out0:   kfree_skb(skb);
 840         return ret;
 841 }
 842
 843 static struct notifier_block aarp_notifier = {
 844         notifier_call:  aarp_device_event,
 845 };
 846
 847 static char aarp_snap_id[] = { 0x00, 0x00, 0x00, 0x80, 0xF3 };
 848
 849 void __init aarp_proto_init(void)
 850 {
 851         aarp_dl = register_snap_client(aarp_snap_id, aarp_rcv);
 852         if (!aarp_dl)
 853                 printk(KERN_CRIT "Unable to register AARP with SNAP.\n");
 854         init_timer(&aarp_timer);
 855         aarp_timer.function = aarp_expire_timeout;
 856         aarp_timer.data = 0;
 857         aarp_timer.expires = jiffies + sysctl_aarp_expiry_time;
 858         add_timer(&aarp_timer);
 859         register_netdevice_notifier(&aarp_notifier);
 860 }
 861
 862 /* Remove the AARP entries associated with a device. */
 863 void aarp_device_down(struct net_device *dev)
 864 {
 865         int ct;
 866
 867         spin_lock_bh(&aarp_lock);
 868
 869         for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 870                 __aarp_expire_device(&resolved[ct], dev);
 871                 __aarp_expire_device(&unresolved[ct], dev);
 872                 __aarp_expire_device(&proxies[ct], dev);
 873         }
 874
 875         spin_unlock_bh(&aarp_lock);
 876 }
 877
 878 /* Called from proc fs */
 879 static int aarp_get_info(char *buffer, char **start, off_t offset, int length)
 880 {
 881         /* we should dump all our AARP entries */
 882         struct aarp_entry *entry;
 883         int len, ct;
 884
 885         len = sprintf(buffer,
 886                 "%-10.10s  %-10.10s%-18.18s%12.12s%12.12s xmit_count  status\n",
 887                 "address", "device", "hw addr", "last_sent", "expires");
 888
 889         spin_lock_bh(&aarp_lock);
 890
 891         for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 892                 for (entry = resolved[ct]; entry; entry = entry->next) {
 893                         len+= sprintf(buffer+len,"%6u:%-3u  ",
 894                                 (unsigned int)ntohs(entry->target_addr.s_net),
 895                                 (unsigned int)(entry->target_addr.s_node));
 896                         len+= sprintf(buffer+len,"%-10.10s",
 897                                 entry->dev->name);
 898                         len+= sprintf(buffer+len,"%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X",
 899                                 (int)(entry->hwaddr[0] & 0x000000FF),
 900                                 (int)(entry->hwaddr[1] & 0x000000FF),
 901                                 (int)(entry->hwaddr[2] & 0x000000FF),
 902                                 (int)(entry->hwaddr[3] & 0x000000FF),
 903                                 (int)(entry->hwaddr[4] & 0x000000FF),
 904                                 (int)(entry->hwaddr[5] & 0x000000FF));
 905                         len+= sprintf(buffer+len,"%12lu ""%12lu ",
 906                                 (unsigned long)entry->last_sent,
 907                                 (unsigned long)entry->expires_at);
 908                         len+=sprintf(buffer+len,"%10u",
 909                                 (unsigned int)entry->xmit_count);
 910
 911                         len+=sprintf(buffer+len,"   resolved\n");
 912                 }
 913         }
 914
 915         for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 916                 for (entry = unresolved[ct]; entry; entry = entry->next) {
 917                         len+= sprintf(buffer+len,"%6u:%-3u  ",
 918                                 (unsigned int)ntohs(entry->target_addr.s_net),
 919                                 (unsigned int)(entry->target_addr.s_node));
 920                         len+= sprintf(buffer+len,"%-10.10s",
 921                                 entry->dev->name);
 922                         len+= sprintf(buffer+len,"%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X",
 923                                 (int)(entry->hwaddr[0] & 0x000000FF),
 924                                 (int)(entry->hwaddr[1] & 0x000000FF),
 925                                 (int)(entry->hwaddr[2] & 0x000000FF),
 926                                 (int)(entry->hwaddr[3] & 0x000000FF),
 927                                 (int)(entry->hwaddr[4] & 0x000000FF),
 928                                 (int)(entry->hwaddr[5] & 0x000000FF));
 929                         len+= sprintf(buffer+len,"%12lu ""%12lu ",
 930                                 (unsigned long)entry->last_sent,
 931                                 (unsigned long)entry->expires_at);
 932                         len+=sprintf(buffer+len,"%10u",
 933                                 (unsigned int)entry->xmit_count);
 934                         len+=sprintf(buffer+len," unresolved\n");
 935                 }
 936         }
 937
 938         for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 939                 for (entry = proxies[ct]; entry; entry = entry->next) {
 940                         len+= sprintf(buffer+len,"%6u:%-3u  ",
 941                                 (unsigned int)ntohs(entry->target_addr.s_net),
 942                                 (unsigned int)(entry->target_addr.s_node));
 943                         len+= sprintf(buffer+len,"%-10.10s",
 944                                 entry->dev->name);
 945                         len+= sprintf(buffer+len,"%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X",
 946                                 (int)(entry->hwaddr[0] & 0x000000FF),
 947                                 (int)(entry->hwaddr[1] & 0x000000FF),
 948                                 (int)(entry->hwaddr[2] & 0x000000FF),
 949                                 (int)(entry->hwaddr[3] & 0x000000FF),
 950                                 (int)(entry->hwaddr[4] & 0x000000FF),
 951                                 (int)(entry->hwaddr[5] & 0x000000FF));
 952                         len+= sprintf(buffer+len,"%12lu ""%12lu ",
 953                                 (unsigned long)entry->last_sent,
 954                                 (unsigned long)entry->expires_at);
 955                         len+=sprintf(buffer+len,"%10u",
 956                                 (unsigned int)entry->xmit_count);
 957                         len+=sprintf(buffer+len,"      proxy\n");
 958                 }
 959         }
 960
 961         spin_unlock_bh(&aarp_lock);
 962         return len;
 963 }
 964
 965 #ifdef MODULE
 966 /* General module cleanup. Called from cleanup_module() in ddp.c. */
 967 void aarp_cleanup_module(void)
 968 {
 969         del_timer(&aarp_timer);
 970         unregister_netdevice_notifier(&aarp_notifier);
 971         unregister_snap_client(aarp_snap_id);
 972 }
 973 #endif  /* MODULE */
 974 #ifdef CONFIG_PROC_FS
 975 void aarp_register_proc_fs(void)
 976 {
 977         proc_net_create("aarp", 0, aarp_get_info);
 978 }
 979
 980 void aarp_unregister_proc_fs(void)
 981 {
 982         proc_net_remove("aarp");
 983 }
 984 #endif
 985 #endif  /* CONFIG_ATALK || CONFIG_ATALK_MODULE */
 986 MODULE_LICENSE("GPL");