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