linux/net/appletalk/aarp.c
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   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/if_arp.h>
  33#include <linux/slab.h>
  34#include <net/sock.h>
  35#include <net/datalink.h>
  36#include <net/psnap.h>
  37#include <linux/atalk.h>
  38#include <linux/delay.h>
  39#include <linux/init.h>
  40#include <linux/proc_fs.h>
  41#include <linux/seq_file.h>
  42#include <linux/export.h>
  43
  44int sysctl_aarp_expiry_time = AARP_EXPIRY_TIME;
  45int sysctl_aarp_tick_time = AARP_TICK_TIME;
  46int sysctl_aarp_retransmit_limit = AARP_RETRANSMIT_LIMIT;
  47int sysctl_aarp_resolve_time = AARP_RESOLVE_TIME;
  48
  49/* Lists of aarp entries */
  50/**
  51 *      struct aarp_entry - AARP entry
  52 *      @last_sent - Last time we xmitted the aarp request
  53 *      @packet_queue - Queue of frames wait for resolution
  54 *      @status - Used for proxy AARP
  55 *      expires_at - Entry expiry time
  56 *      target_addr - DDP Address
  57 *      dev - Device to use
  58 *      hwaddr - Physical i/f address of target/router
  59 *      xmit_count - When this hits 10 we give up
  60 *      next - Next entry in chain
  61 */
  62struct aarp_entry {
  63        /* These first two are only used for unresolved entries */
  64        unsigned long           last_sent;
  65        struct sk_buff_head     packet_queue;
  66        int                     status;
  67        unsigned long           expires_at;
  68        struct atalk_addr       target_addr;
  69        struct net_device       *dev;
  70        char                    hwaddr[6];
  71        unsigned short          xmit_count;
  72        struct aarp_entry       *next;
  73};
  74
  75/* Hashed list of resolved, unresolved and proxy entries */
  76static struct aarp_entry *resolved[AARP_HASH_SIZE];
  77static struct aarp_entry *unresolved[AARP_HASH_SIZE];
  78static struct aarp_entry *proxies[AARP_HASH_SIZE];
  79static int unresolved_count;
  80
  81/* One lock protects it all. */
  82static DEFINE_RWLOCK(aarp_lock);
  83
  84/* Used to walk the list and purge/kick entries.  */
  85static struct timer_list aarp_timer;
  86
  87/*
  88 *      Delete an aarp queue
  89 *
  90 *      Must run under aarp_lock.
  91 */
  92static void __aarp_expire(struct aarp_entry *a)
  93{
  94        skb_queue_purge(&a->packet_queue);
  95        kfree(a);
  96}
  97
  98/*
  99 *      Send an aarp queue entry request
 100 *
 101 *      Must run under aarp_lock.
 102 */
 103static void __aarp_send_query(struct aarp_entry *a)
 104{
 105        static unsigned char aarp_eth_multicast[ETH_ALEN] =
 106                                        { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF };
 107        struct net_device *dev = a->dev;
 108        struct elapaarp *eah;
 109        int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length;
 110        struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 111        struct atalk_addr *sat = atalk_find_dev_addr(dev);
 112
 113        if (!skb)
 114                return;
 115
 116        if (!sat) {
 117                kfree_skb(skb);
 118                return;
 119        }
 120
 121        /* Set up the buffer */
 122        skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length);
 123        skb_reset_network_header(skb);
 124        skb_reset_transport_header(skb);
 125        skb_put(skb, sizeof(*eah));
 126        skb->protocol    = htons(ETH_P_ATALK);
 127        skb->dev         = dev;
 128        eah              = aarp_hdr(skb);
 129
 130        /* Set up the ARP */
 131        eah->hw_type     = htons(AARP_HW_TYPE_ETHERNET);
 132        eah->pa_type     = htons(ETH_P_ATALK);
 133        eah->hw_len      = ETH_ALEN;
 134        eah->pa_len      = AARP_PA_ALEN;
 135        eah->function    = htons(AARP_REQUEST);
 136
 137        memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN);
 138
 139        eah->pa_src_zero = 0;
 140        eah->pa_src_net  = sat->s_net;
 141        eah->pa_src_node = sat->s_node;
 142
 143        memset(eah->hw_dst, '\0', ETH_ALEN);
 144
 145        eah->pa_dst_zero = 0;
 146        eah->pa_dst_net  = a->target_addr.s_net;
 147        eah->pa_dst_node = a->target_addr.s_node;
 148
 149        /* Send it */
 150        aarp_dl->request(aarp_dl, skb, aarp_eth_multicast);
 151        /* Update the sending count */
 152        a->xmit_count++;
 153        a->last_sent = jiffies;
 154}
 155
 156/* This runs under aarp_lock and in softint context, so only atomic memory
 157 * allocations can be used. */
 158static void aarp_send_reply(struct net_device *dev, struct atalk_addr *us,
 159                            struct atalk_addr *them, unsigned char *sha)
 160{
 161        struct elapaarp *eah;
 162        int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length;
 163        struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 164
 165        if (!skb)
 166                return;
 167
 168        /* Set up the buffer */
 169        skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length);
 170        skb_reset_network_header(skb);
 171        skb_reset_transport_header(skb);
 172        skb_put(skb, sizeof(*eah));
 173        skb->protocol    = htons(ETH_P_ATALK);
 174        skb->dev         = dev;
 175        eah              = aarp_hdr(skb);
 176
 177        /* Set up the ARP */
 178        eah->hw_type     = htons(AARP_HW_TYPE_ETHERNET);
 179        eah->pa_type     = htons(ETH_P_ATALK);
 180        eah->hw_len      = ETH_ALEN;
 181        eah->pa_len      = AARP_PA_ALEN;
 182        eah->function    = htons(AARP_REPLY);
 183
 184        memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN);
 185
 186        eah->pa_src_zero = 0;
 187        eah->pa_src_net  = us->s_net;
 188        eah->pa_src_node = us->s_node;
 189
 190        if (!sha)
 191                memset(eah->hw_dst, '\0', ETH_ALEN);
 192        else
 193                memcpy(eah->hw_dst, sha, ETH_ALEN);
 194
 195        eah->pa_dst_zero = 0;
 196        eah->pa_dst_net  = them->s_net;
 197        eah->pa_dst_node = them->s_node;
 198
 199        /* Send it */
 200        aarp_dl->request(aarp_dl, skb, sha);
 201}
 202
 203/*
 204 *      Send probe frames. Called from aarp_probe_network and
 205 *      aarp_proxy_probe_network.
 206 */
 207
 208static void aarp_send_probe(struct net_device *dev, struct atalk_addr *us)
 209{
 210        struct elapaarp *eah;
 211        int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length;
 212        struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 213        static unsigned char aarp_eth_multicast[ETH_ALEN] =
 214                                        { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF };
 215
 216        if (!skb)
 217                return;
 218
 219        /* Set up the buffer */
 220        skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length);
 221        skb_reset_network_header(skb);
 222        skb_reset_transport_header(skb);
 223        skb_put(skb, sizeof(*eah));
 224        skb->protocol    = htons(ETH_P_ATALK);
 225        skb->dev         = dev;
 226        eah              = aarp_hdr(skb);
 227
 228        /* Set up the ARP */
 229        eah->hw_type     = htons(AARP_HW_TYPE_ETHERNET);
 230        eah->pa_type     = htons(ETH_P_ATALK);
 231        eah->hw_len      = ETH_ALEN;
 232        eah->pa_len      = AARP_PA_ALEN;
 233        eah->function    = htons(AARP_PROBE);
 234
 235        memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN);
 236
 237        eah->pa_src_zero = 0;
 238        eah->pa_src_net  = us->s_net;
 239        eah->pa_src_node = us->s_node;
 240
 241        memset(eah->hw_dst, '\0', ETH_ALEN);
 242
 243        eah->pa_dst_zero = 0;
 244        eah->pa_dst_net  = us->s_net;
 245        eah->pa_dst_node = us->s_node;
 246
 247        /* Send it */
 248        aarp_dl->request(aarp_dl, skb, aarp_eth_multicast);
 249}
 250
 251/*
 252 *      Handle an aarp timer expire
 253 *
 254 *      Must run under the aarp_lock.
 255 */
 256
 257static void __aarp_expire_timer(struct aarp_entry **n)
 258{
 259        struct aarp_entry *t;
 260
 261        while (*n)
 262                /* Expired ? */
 263                if (time_after(jiffies, (*n)->expires_at)) {
 264                        t = *n;
 265                        *n = (*n)->next;
 266                        __aarp_expire(t);
 267                } else
 268                        n = &((*n)->next);
 269}
 270
 271/*
 272 *      Kick all pending requests 5 times a second.
 273 *
 274 *      Must run under the aarp_lock.
 275 */
 276static void __aarp_kick(struct aarp_entry **n)
 277{
 278        struct aarp_entry *t;
 279
 280        while (*n)
 281                /* Expired: if this will be the 11th tx, we delete instead. */
 282                if ((*n)->xmit_count >= sysctl_aarp_retransmit_limit) {
 283                        t = *n;
 284                        *n = (*n)->next;
 285                        __aarp_expire(t);
 286                } else {
 287                        __aarp_send_query(*n);
 288                        n = &((*n)->next);
 289                }
 290}
 291
 292/*
 293 *      A device has gone down. Take all entries referring to the device
 294 *      and remove them.
 295 *
 296 *      Must run under the aarp_lock.
 297 */
 298static void __aarp_expire_device(struct aarp_entry **n, struct net_device *dev)
 299{
 300        struct aarp_entry *t;
 301
 302        while (*n)
 303                if ((*n)->dev == dev) {
 304                        t = *n;
 305                        *n = (*n)->next;
 306                        __aarp_expire(t);
 307                } else
 308                        n = &((*n)->next);
 309}
 310
 311/* Handle the timer event */
 312static void aarp_expire_timeout(unsigned long unused)
 313{
 314        int ct;
 315
 316        write_lock_bh(&aarp_lock);
 317
 318        for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 319                __aarp_expire_timer(&resolved[ct]);
 320                __aarp_kick(&unresolved[ct]);
 321                __aarp_expire_timer(&unresolved[ct]);
 322                __aarp_expire_timer(&proxies[ct]);
 323        }
 324
 325        write_unlock_bh(&aarp_lock);
 326        mod_timer(&aarp_timer, jiffies +
 327                               (unresolved_count ? sysctl_aarp_tick_time :
 328                                sysctl_aarp_expiry_time));
 329}
 330
 331/* Network device notifier chain handler. */
 332static int aarp_device_event(struct notifier_block *this, unsigned long event,
 333                             void *ptr)
 334{
 335        struct net_device *dev = ptr;
 336        int ct;
 337
 338        if (!net_eq(dev_net(dev), &init_net))
 339                return NOTIFY_DONE;
 340
 341        if (event == NETDEV_DOWN) {
 342                write_lock_bh(&aarp_lock);
 343
 344                for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 345                        __aarp_expire_device(&resolved[ct], dev);
 346                        __aarp_expire_device(&unresolved[ct], dev);
 347                        __aarp_expire_device(&proxies[ct], dev);
 348                }
 349
 350                write_unlock_bh(&aarp_lock);
 351        }
 352        return NOTIFY_DONE;
 353}
 354
 355/* Expire all entries in a hash chain */
 356static void __aarp_expire_all(struct aarp_entry **n)
 357{
 358        struct aarp_entry *t;
 359
 360        while (*n) {
 361                t = *n;
 362                *n = (*n)->next;
 363                __aarp_expire(t);
 364        }
 365}
 366
 367/* Cleanup all hash chains -- module unloading */
 368static void aarp_purge(void)
 369{
 370        int ct;
 371
 372        write_lock_bh(&aarp_lock);
 373        for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 374                __aarp_expire_all(&resolved[ct]);
 375                __aarp_expire_all(&unresolved[ct]);
 376                __aarp_expire_all(&proxies[ct]);
 377        }
 378        write_unlock_bh(&aarp_lock);
 379}
 380
 381/*
 382 *      Create a new aarp entry.  This must use GFP_ATOMIC because it
 383 *      runs while holding spinlocks.
 384 */
 385static struct aarp_entry *aarp_alloc(void)
 386{
 387        struct aarp_entry *a = kmalloc(sizeof(*a), GFP_ATOMIC);
 388
 389        if (a)
 390                skb_queue_head_init(&a->packet_queue);
 391        return a;
 392}
 393
 394/*
 395 * Find an entry. We might return an expired but not yet purged entry. We
 396 * don't care as it will do no harm.
 397 *
 398 * This must run under the aarp_lock.
 399 */
 400static struct aarp_entry *__aarp_find_entry(struct aarp_entry *list,
 401                                            struct net_device *dev,
 402                                            struct atalk_addr *sat)
 403{
 404        while (list) {
 405                if (list->target_addr.s_net == sat->s_net &&
 406                    list->target_addr.s_node == sat->s_node &&
 407                    list->dev == dev)
 408                        break;
 409                list = list->next;
 410        }
 411
 412        return list;
 413}
 414
 415/* Called from the DDP code, and thus must be exported. */
 416void aarp_proxy_remove(struct net_device *dev, struct atalk_addr *sa)
 417{
 418        int hash = sa->s_node % (AARP_HASH_SIZE - 1);
 419        struct aarp_entry *a;
 420
 421        write_lock_bh(&aarp_lock);
 422
 423        a = __aarp_find_entry(proxies[hash], dev, sa);
 424        if (a)
 425                a->expires_at = jiffies - 1;
 426
 427        write_unlock_bh(&aarp_lock);
 428}
 429
 430/* This must run under aarp_lock. */
 431static struct atalk_addr *__aarp_proxy_find(struct net_device *dev,
 432                                            struct atalk_addr *sa)
 433{
 434        int hash = sa->s_node % (AARP_HASH_SIZE - 1);
 435        struct aarp_entry *a = __aarp_find_entry(proxies[hash], dev, sa);
 436
 437        return a ? sa : NULL;
 438}
 439
 440/*
 441 * Probe a Phase 1 device or a device that requires its Net:Node to
 442 * be set via an ioctl.
 443 */
 444static void aarp_send_probe_phase1(struct atalk_iface *iface)
 445{
 446        struct ifreq atreq;
 447        struct sockaddr_at *sa = (struct sockaddr_at *)&atreq.ifr_addr;
 448        const struct net_device_ops *ops = iface->dev->netdev_ops;
 449
 450        sa->sat_addr.s_node = iface->address.s_node;
 451        sa->sat_addr.s_net = ntohs(iface->address.s_net);
 452
 453        /* We pass the Net:Node to the drivers/cards by a Device ioctl. */
 454        if (!(ops->ndo_do_ioctl(iface->dev, &atreq, SIOCSIFADDR))) {
 455                ops->ndo_do_ioctl(iface->dev, &atreq, SIOCGIFADDR);
 456                if (iface->address.s_net != htons(sa->sat_addr.s_net) ||
 457                    iface->address.s_node != sa->sat_addr.s_node)
 458                        iface->status |= ATIF_PROBE_FAIL;
 459
 460                iface->address.s_net  = htons(sa->sat_addr.s_net);
 461                iface->address.s_node = sa->sat_addr.s_node;
 462        }
 463}
 464
 465
 466void aarp_probe_network(struct atalk_iface *atif)
 467{
 468        if (atif->dev->type == ARPHRD_LOCALTLK ||
 469            atif->dev->type == ARPHRD_PPP)
 470                aarp_send_probe_phase1(atif);
 471        else {
 472                unsigned int count;
 473
 474                for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) {
 475                        aarp_send_probe(atif->dev, &atif->address);
 476
 477                        /* Defer 1/10th */
 478                        msleep(100);
 479
 480                        if (atif->status & ATIF_PROBE_FAIL)
 481                                break;
 482                }
 483        }
 484}
 485
 486int aarp_proxy_probe_network(struct atalk_iface *atif, struct atalk_addr *sa)
 487{
 488        int hash, retval = -EPROTONOSUPPORT;
 489        struct aarp_entry *entry;
 490        unsigned int count;
 491
 492        /*
 493         * we don't currently support LocalTalk or PPP for proxy AARP;
 494         * if someone wants to try and add it, have fun
 495         */
 496        if (atif->dev->type == ARPHRD_LOCALTLK ||
 497            atif->dev->type == ARPHRD_PPP)
 498                goto out;
 499
 500        /*
 501         * create a new AARP entry with the flags set to be published --
 502         * we need this one to hang around even if it's in use
 503         */
 504        entry = aarp_alloc();
 505        retval = -ENOMEM;
 506        if (!entry)
 507                goto out;
 508
 509        entry->expires_at = -1;
 510        entry->status = ATIF_PROBE;
 511        entry->target_addr.s_node = sa->s_node;
 512        entry->target_addr.s_net = sa->s_net;
 513        entry->dev = atif->dev;
 514
 515        write_lock_bh(&aarp_lock);
 516
 517        hash = sa->s_node % (AARP_HASH_SIZE - 1);
 518        entry->next = proxies[hash];
 519        proxies[hash] = entry;
 520
 521        for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) {
 522                aarp_send_probe(atif->dev, sa);
 523
 524                /* Defer 1/10th */
 525                write_unlock_bh(&aarp_lock);
 526                msleep(100);
 527                write_lock_bh(&aarp_lock);
 528
 529                if (entry->status & ATIF_PROBE_FAIL)
 530                        break;
 531        }
 532
 533        if (entry->status & ATIF_PROBE_FAIL) {
 534                entry->expires_at = jiffies - 1; /* free the entry */
 535                retval = -EADDRINUSE; /* return network full */
 536        } else { /* clear the probing flag */
 537                entry->status &= ~ATIF_PROBE;
 538                retval = 1;
 539        }
 540
 541        write_unlock_bh(&aarp_lock);
 542out:
 543        return retval;
 544}
 545
 546/* Send a DDP frame */
 547int aarp_send_ddp(struct net_device *dev, struct sk_buff *skb,
 548                  struct atalk_addr *sa, void *hwaddr)
 549{
 550        static char ddp_eth_multicast[ETH_ALEN] =
 551                { 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF };
 552        int hash;
 553        struct aarp_entry *a;
 554
 555        skb_reset_network_header(skb);
 556
 557        /* Check for LocalTalk first */
 558        if (dev->type == ARPHRD_LOCALTLK) {
 559                struct atalk_addr *at = atalk_find_dev_addr(dev);
 560                struct ddpehdr *ddp = (struct ddpehdr *)skb->data;
 561                int ft = 2;
 562
 563                /*
 564                 * Compressible ?
 565                 *
 566                 * IFF: src_net == dest_net == device_net
 567                 * (zero matches anything)
 568                 */
 569
 570                if ((!ddp->deh_snet || at->s_net == ddp->deh_snet) &&
 571                    (!ddp->deh_dnet || at->s_net == ddp->deh_dnet)) {
 572                        skb_pull(skb, sizeof(*ddp) - 4);
 573
 574                        /*
 575                         *      The upper two remaining bytes are the port
 576                         *      numbers we just happen to need. Now put the
 577                         *      length in the lower two.
 578                         */
 579                        *((__be16 *)skb->data) = htons(skb->len);
 580                        ft = 1;
 581                }
 582                /*
 583                 * Nice and easy. No AARP type protocols occur here so we can
 584                 * just shovel it out with a 3 byte LLAP header
 585                 */
 586
 587                skb_push(skb, 3);
 588                skb->data[0] = sa->s_node;
 589                skb->data[1] = at->s_node;
 590                skb->data[2] = ft;
 591                skb->dev     = dev;
 592                goto sendit;
 593        }
 594
 595        /* On a PPP link we neither compress nor aarp.  */
 596        if (dev->type == ARPHRD_PPP) {
 597                skb->protocol = htons(ETH_P_PPPTALK);
 598                skb->dev = dev;
 599                goto sendit;
 600        }
 601
 602        /* Non ELAP we cannot do. */
 603        if (dev->type != ARPHRD_ETHER)
 604                goto free_it;
 605
 606        skb->dev = dev;
 607        skb->protocol = htons(ETH_P_ATALK);
 608        hash = sa->s_node % (AARP_HASH_SIZE - 1);
 609
 610        /* Do we have a resolved entry? */
 611        if (sa->s_node == ATADDR_BCAST) {
 612                /* Send it */
 613                ddp_dl->request(ddp_dl, skb, ddp_eth_multicast);
 614                goto sent;
 615        }
 616
 617        write_lock_bh(&aarp_lock);
 618        a = __aarp_find_entry(resolved[hash], dev, sa);
 619
 620        if (a) { /* Return 1 and fill in the address */
 621                a->expires_at = jiffies + (sysctl_aarp_expiry_time * 10);
 622                ddp_dl->request(ddp_dl, skb, a->hwaddr);
 623                write_unlock_bh(&aarp_lock);
 624                goto sent;
 625        }
 626
 627        /* Do we have an unresolved entry: This is the less common path */
 628        a = __aarp_find_entry(unresolved[hash], dev, sa);
 629        if (a) { /* Queue onto the unresolved queue */
 630                skb_queue_tail(&a->packet_queue, skb);
 631                goto out_unlock;
 632        }
 633
 634        /* Allocate a new entry */
 635        a = aarp_alloc();
 636        if (!a) {
 637                /* Whoops slipped... good job it's an unreliable protocol 8) */
 638                write_unlock_bh(&aarp_lock);
 639                goto free_it;
 640        }
 641
 642        /* Set up the queue */
 643        skb_queue_tail(&a->packet_queue, skb);
 644        a->expires_at    = jiffies + sysctl_aarp_resolve_time;
 645        a->dev           = dev;
 646        a->next          = unresolved[hash];
 647        a->target_addr   = *sa;
 648        a->xmit_count    = 0;
 649        unresolved[hash] = a;
 650        unresolved_count++;
 651
 652        /* Send an initial request for the address */
 653        __aarp_send_query(a);
 654
 655        /*
 656         * Switch to fast timer if needed (That is if this is the first
 657         * unresolved entry to get added)
 658         */
 659
 660        if (unresolved_count == 1)
 661                mod_timer(&aarp_timer, jiffies + sysctl_aarp_tick_time);
 662
 663        /* Now finally, it is safe to drop the lock. */
 664out_unlock:
 665        write_unlock_bh(&aarp_lock);
 666
 667        /* Tell the ddp layer we have taken over for this frame. */
 668        goto sent;
 669
 670sendit:
 671        if (skb->sk)
 672                skb->priority = skb->sk->sk_priority;
 673        if (dev_queue_xmit(skb))
 674                goto drop;
 675sent:
 676        return NET_XMIT_SUCCESS;
 677free_it:
 678        kfree_skb(skb);
 679drop:
 680        return NET_XMIT_DROP;
 681}
 682EXPORT_SYMBOL(aarp_send_ddp);
 683
 684/*
 685 *      An entry in the aarp unresolved queue has become resolved. Send
 686 *      all the frames queued under it.
 687 *
 688 *      Must run under aarp_lock.
 689 */
 690static void __aarp_resolved(struct aarp_entry **list, struct aarp_entry *a,
 691                            int hash)
 692{
 693        struct sk_buff *skb;
 694
 695        while (*list)
 696                if (*list == a) {
 697                        unresolved_count--;
 698                        *list = a->next;
 699
 700                        /* Move into the resolved list */
 701                        a->next = resolved[hash];
 702                        resolved[hash] = a;
 703
 704                        /* Kick frames off */
 705                        while ((skb = skb_dequeue(&a->packet_queue)) != NULL) {
 706                                a->expires_at = jiffies +
 707                                                sysctl_aarp_expiry_time * 10;
 708                                ddp_dl->request(ddp_dl, skb, a->hwaddr);
 709                        }
 710                } else
 711                        list = &((*list)->next);
 712}
 713
 714/*
 715 *      This is called by the SNAP driver whenever we see an AARP SNAP
 716 *      frame. We currently only support Ethernet.
 717 */
 718static int aarp_rcv(struct sk_buff *skb, struct net_device *dev,
 719                    struct packet_type *pt, struct net_device *orig_dev)
 720{
 721        struct elapaarp *ea = aarp_hdr(skb);
 722        int hash, ret = 0;
 723        __u16 function;
 724        struct aarp_entry *a;
 725        struct atalk_addr sa, *ma, da;
 726        struct atalk_iface *ifa;
 727
 728        if (!net_eq(dev_net(dev), &init_net))
 729                goto out0;
 730
 731        /* We only do Ethernet SNAP AARP. */
 732        if (dev->type != ARPHRD_ETHER)
 733                goto out0;
 734
 735        /* Frame size ok? */
 736        if (!skb_pull(skb, sizeof(*ea)))
 737                goto out0;
 738
 739        function = ntohs(ea->function);
 740
 741        /* Sanity check fields. */
 742        if (function < AARP_REQUEST || function > AARP_PROBE ||
 743            ea->hw_len != ETH_ALEN || ea->pa_len != AARP_PA_ALEN ||
 744            ea->pa_src_zero || ea->pa_dst_zero)
 745                goto out0;
 746
 747        /* Looks good. */
 748        hash = ea->pa_src_node % (AARP_HASH_SIZE - 1);
 749
 750        /* Build an address. */
 751        sa.s_node = ea->pa_src_node;
 752        sa.s_net = ea->pa_src_net;
 753
 754        /* Process the packet. Check for replies of me. */
 755        ifa = atalk_find_dev(dev);
 756        if (!ifa)
 757                goto out1;
 758
 759        if (ifa->status & ATIF_PROBE &&
 760            ifa->address.s_node == ea->pa_dst_node &&
 761            ifa->address.s_net == ea->pa_dst_net) {
 762                ifa->status |= ATIF_PROBE_FAIL; /* Fail the probe (in use) */
 763                goto out1;
 764        }
 765
 766        /* Check for replies of proxy AARP entries */
 767        da.s_node = ea->pa_dst_node;
 768        da.s_net  = ea->pa_dst_net;
 769
 770        write_lock_bh(&aarp_lock);
 771        a = __aarp_find_entry(proxies[hash], dev, &da);
 772
 773        if (a && a->status & ATIF_PROBE) {
 774                a->status |= ATIF_PROBE_FAIL;
 775                /*
 776                 * we do not respond to probe or request packets for
 777                 * this address while we are probing this address
 778                 */
 779                goto unlock;
 780        }
 781
 782        switch (function) {
 783        case AARP_REPLY:
 784                if (!unresolved_count)  /* Speed up */
 785                        break;
 786
 787                /* Find the entry.  */
 788                a = __aarp_find_entry(unresolved[hash], dev, &sa);
 789                if (!a || dev != a->dev)
 790                        break;
 791
 792                /* We can fill one in - this is good. */
 793                memcpy(a->hwaddr, ea->hw_src, ETH_ALEN);
 794                __aarp_resolved(&unresolved[hash], a, hash);
 795                if (!unresolved_count)
 796                        mod_timer(&aarp_timer,
 797                                  jiffies + sysctl_aarp_expiry_time);
 798                break;
 799
 800        case AARP_REQUEST:
 801        case AARP_PROBE:
 802
 803                /*
 804                 * If it is my address set ma to my address and reply.
 805                 * We can treat probe and request the same.  Probe
 806                 * simply means we shouldn't cache the querying host,
 807                 * as in a probe they are proposing an address not
 808                 * using one.
 809                 *
 810                 * Support for proxy-AARP added. We check if the
 811                 * address is one of our proxies before we toss the
 812                 * packet out.
 813                 */
 814
 815                sa.s_node = ea->pa_dst_node;
 816                sa.s_net  = ea->pa_dst_net;
 817
 818                /* See if we have a matching proxy. */
 819                ma = __aarp_proxy_find(dev, &sa);
 820                if (!ma)
 821                        ma = &ifa->address;
 822                else { /* We need to make a copy of the entry. */
 823                        da.s_node = sa.s_node;
 824                        da.s_net = sa.s_net;
 825                        ma = &da;
 826                }
 827
 828                if (function == AARP_PROBE) {
 829                        /*
 830                         * A probe implies someone trying to get an
 831                         * address. So as a precaution flush any
 832                         * entries we have for this address.
 833                         */
 834                        a = __aarp_find_entry(resolved[sa.s_node %
 835                                                       (AARP_HASH_SIZE - 1)],
 836                                              skb->dev, &sa);
 837
 838                        /*
 839                         * Make it expire next tick - that avoids us
 840                         * getting into a probe/flush/learn/probe/
 841                         * flush/learn cycle during probing of a slow
 842                         * to respond host addr.
 843                         */
 844                        if (a) {
 845                                a->expires_at = jiffies - 1;
 846                                mod_timer(&aarp_timer, jiffies +
 847                                          sysctl_aarp_tick_time);
 848                        }
 849                }
 850
 851                if (sa.s_node != ma->s_node)
 852                        break;
 853
 854                if (sa.s_net && ma->s_net && sa.s_net != ma->s_net)
 855                        break;
 856
 857                sa.s_node = ea->pa_src_node;
 858                sa.s_net = ea->pa_src_net;
 859
 860                /* aarp_my_address has found the address to use for us.
 861                 */
 862                aarp_send_reply(dev, ma, &sa, ea->hw_src);
 863                break;
 864        }
 865
 866unlock:
 867        write_unlock_bh(&aarp_lock);
 868out1:
 869        ret = 1;
 870out0:
 871        kfree_skb(skb);
 872        return ret;
 873}
 874
 875static struct notifier_block aarp_notifier = {
 876        .notifier_call = aarp_device_event,
 877};
 878
 879static unsigned char aarp_snap_id[] = { 0x00, 0x00, 0x00, 0x80, 0xF3 };
 880
 881void __init aarp_proto_init(void)
 882{
 883        aarp_dl = register_snap_client(aarp_snap_id, aarp_rcv);
 884        if (!aarp_dl)
 885                printk(KERN_CRIT "Unable to register AARP with SNAP.\n");
 886        setup_timer(&aarp_timer, aarp_expire_timeout, 0);
 887        aarp_timer.expires  = jiffies + sysctl_aarp_expiry_time;
 888        add_timer(&aarp_timer);
 889        register_netdevice_notifier(&aarp_notifier);
 890}
 891
 892/* Remove the AARP entries associated with a device. */
 893void aarp_device_down(struct net_device *dev)
 894{
 895        int ct;
 896
 897        write_lock_bh(&aarp_lock);
 898
 899        for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
 900                __aarp_expire_device(&resolved[ct], dev);
 901                __aarp_expire_device(&unresolved[ct], dev);
 902                __aarp_expire_device(&proxies[ct], dev);
 903        }
 904
 905        write_unlock_bh(&aarp_lock);
 906}
 907
 908#ifdef CONFIG_PROC_FS
 909struct aarp_iter_state {
 910        int bucket;
 911        struct aarp_entry **table;
 912};
 913
 914/*
 915 * Get the aarp entry that is in the chain described
 916 * by the iterator.
 917 * If pos is set then skip till that index.
 918 * pos = 1 is the first entry
 919 */
 920static struct aarp_entry *iter_next(struct aarp_iter_state *iter, loff_t *pos)
 921{
 922        int ct = iter->bucket;
 923        struct aarp_entry **table = iter->table;
 924        loff_t off = 0;
 925        struct aarp_entry *entry;
 926
 927 rescan:
 928        while(ct < AARP_HASH_SIZE) {
 929                for (entry = table[ct]; entry; entry = entry->next) {
 930                        if (!pos || ++off == *pos) {
 931                                iter->table = table;
 932                                iter->bucket = ct;
 933                                return entry;
 934                        }
 935                }
 936                ++ct;
 937        }
 938
 939        if (table == resolved) {
 940                ct = 0;
 941                table = unresolved;
 942                goto rescan;
 943        }
 944        if (table == unresolved) {
 945                ct = 0;
 946                table = proxies;
 947                goto rescan;
 948        }
 949        return NULL;
 950}
 951
 952static void *aarp_seq_start(struct seq_file *seq, loff_t *pos)
 953        __acquires(aarp_lock)
 954{
 955        struct aarp_iter_state *iter = seq->private;
 956
 957        read_lock_bh(&aarp_lock);
 958        iter->table     = resolved;
 959        iter->bucket    = 0;
 960
 961        return *pos ? iter_next(iter, pos) : SEQ_START_TOKEN;
 962}
 963
 964static void *aarp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 965{
 966        struct aarp_entry *entry = v;
 967        struct aarp_iter_state *iter = seq->private;
 968
 969        ++*pos;
 970
 971        /* first line after header */
 972        if (v == SEQ_START_TOKEN)
 973                entry = iter_next(iter, NULL);
 974
 975        /* next entry in current bucket */
 976        else if (entry->next)
 977                entry = entry->next;
 978
 979        /* next bucket or table */
 980        else {
 981                ++iter->bucket;
 982                entry = iter_next(iter, NULL);
 983        }
 984        return entry;
 985}
 986
 987static void aarp_seq_stop(struct seq_file *seq, void *v)
 988        __releases(aarp_lock)
 989{
 990        read_unlock_bh(&aarp_lock);
 991}
 992
 993static const char *dt2str(unsigned long ticks)
 994{
 995        static char buf[32];
 996
 997        sprintf(buf, "%ld.%02ld", ticks / HZ, ((ticks % HZ) * 100 ) / HZ);
 998
 999        return buf;
1000}
1001
1002static int aarp_seq_show(struct seq_file *seq, void *v)
1003{
1004        struct aarp_iter_state *iter = seq->private;
1005        struct aarp_entry *entry = v;
1006        unsigned long now = jiffies;
1007
1008        if (v == SEQ_START_TOKEN)
1009                seq_puts(seq,
1010                         "Address  Interface   Hardware Address"
1011                         "   Expires LastSend  Retry Status\n");
1012        else {
1013                seq_printf(seq, "%04X:%02X  %-12s",
1014                           ntohs(entry->target_addr.s_net),
1015                           (unsigned int) entry->target_addr.s_node,
1016                           entry->dev ? entry->dev->name : "????");
1017                seq_printf(seq, "%pM", entry->hwaddr);
1018                seq_printf(seq, " %8s",
1019                           dt2str((long)entry->expires_at - (long)now));
1020                if (iter->table == unresolved)
1021                        seq_printf(seq, " %8s %6hu",
1022                                   dt2str(now - entry->last_sent),
1023                                   entry->xmit_count);
1024                else
1025                        seq_puts(seq, "                ");
1026                seq_printf(seq, " %s\n",
1027                           (iter->table == resolved) ? "resolved"
1028                           : (iter->table == unresolved) ? "unresolved"
1029                           : (iter->table == proxies) ? "proxies"
1030                           : "unknown");
1031        }
1032        return 0;
1033}
1034
1035static const struct seq_operations aarp_seq_ops = {
1036        .start  = aarp_seq_start,
1037        .next   = aarp_seq_next,
1038        .stop   = aarp_seq_stop,
1039        .show   = aarp_seq_show,
1040};
1041
1042static int aarp_seq_open(struct inode *inode, struct file *file)
1043{
1044        return seq_open_private(file, &aarp_seq_ops,
1045                        sizeof(struct aarp_iter_state));
1046}
1047
1048const struct file_operations atalk_seq_arp_fops = {
1049        .owner          = THIS_MODULE,
1050        .open           = aarp_seq_open,
1051        .read           = seq_read,
1052        .llseek         = seq_lseek,
1053        .release        = seq_release_private,
1054};
1055#endif
1056
1057/* General module cleanup. Called from cleanup_module() in ddp.c. */
1058void aarp_cleanup_module(void)
1059{
1060        del_timer_sync(&aarp_timer);
1061        unregister_netdevice_notifier(&aarp_notifier);
1062        unregister_snap_client(aarp_dl);
1063        aarp_purge();
1064}
1065
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