net/atm/clip.c

   1 /* net/atm/clip.c - RFC1577 Classical IP over ATM */
   2
   3 /* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
   4
   5 #include <linux/string.h>
   6 #include <linux/errno.h>
   7 #include <linux/kernel.h> /* for UINT_MAX */
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/netdevice.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/wait.h>
  13 #include <linux/timer.h>
  14 #include <linux/if_arp.h> /* for some manifest constants */
  15 #include <linux/notifier.h>
  16 #include <linux/atm.h>
  17 #include <linux/atmdev.h>
  18 #include <linux/atmclip.h>
  19 #include <linux/atmarp.h>
  20 #include <linux/capability.h>
  21 #include <linux/ip.h> /* for net/route.h */
  22 #include <linux/in.h> /* for struct sockaddr_in */
  23 #include <linux/if.h> /* for IFF_UP */
  24 #include <linux/inetdevice.h>
  25 #include <linux/bitops.h>
  26 #include <linux/poison.h>
  27 #include <linux/proc_fs.h>
  28 #include <linux/seq_file.h>
  29 #include <linux/rcupdate.h>
  30 #include <linux/jhash.h>
  31 #include <net/route.h> /* for struct rtable and routing */
  32 #include <net/icmp.h> /* icmp_send */
  33 #include <asm/param.h> /* for HZ */
  34 #include <asm/byteorder.h> /* for htons etc. */
  35 #include <asm/system.h> /* save/restore_flags */
  36 #include <asm/uaccess.h>
  37 #include <asm/atomic.h>
  38
  39 #include "common.h"
  40 #include "resources.h"
  41 #include <net/atmclip.h>
  42
  43 static struct net_device *clip_devs;
  44 static struct atm_vcc *atmarpd;
  45 static struct neigh_table clip_tbl;
  46 static struct timer_list idle_timer;
  47
  48 static int to_atmarpd(enum atmarp_ctrl_type type, int itf, __be32 ip)
  49 {
  50         struct sock *sk;
  51         struct atmarp_ctrl *ctrl;
  52         struct sk_buff *skb;
  53
  54         pr_debug("to_atmarpd(%d)\n", type);
  55         if (!atmarpd)
  56                 return -EUNATCH;
  57         skb = alloc_skb(sizeof(struct atmarp_ctrl),GFP_ATOMIC);
  58         if (!skb)
  59                 return -ENOMEM;
  60         ctrl = (struct atmarp_ctrl *) skb_put(skb,sizeof(struct atmarp_ctrl));
  61         ctrl->type = type;
  62         ctrl->itf_num = itf;
  63         ctrl->ip = ip;
  64         atm_force_charge(atmarpd, skb->truesize);
  65
  66         sk = sk_atm(atmarpd);
  67         skb_queue_tail(&sk->sk_receive_queue, skb);
  68         sk->sk_data_ready(sk, skb->len);
  69         return 0;
  70 }
  71
  72 static void link_vcc(struct clip_vcc *clip_vcc, struct atmarp_entry *entry)
  73 {
  74         pr_debug("link_vcc %p to entry %p (neigh %p)\n", clip_vcc, entry,
  75                 entry->neigh);
  76         clip_vcc->entry = entry;
  77         clip_vcc->xoff = 0;     /* @@@ may overrun buffer by one packet */
  78         clip_vcc->next = entry->vccs;
  79         entry->vccs = clip_vcc;
  80         entry->neigh->used = jiffies;
  81 }
  82
  83 static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
  84 {
  85         struct atmarp_entry *entry = clip_vcc->entry;
  86         struct clip_vcc **walk;
  87
  88         if (!entry) {
  89                 printk(KERN_CRIT "!clip_vcc->entry (clip_vcc %p)\n", clip_vcc);
  90                 return;
  91         }
  92         netif_tx_lock_bh(entry->neigh->dev);    /* block clip_start_xmit() */
  93         entry->neigh->used = jiffies;
  94         for (walk = &entry->vccs; *walk; walk = &(*walk)->next)
  95                 if (*walk == clip_vcc) {
  96                         int error;
  97
  98                         *walk = clip_vcc->next; /* atomic */
  99                         clip_vcc->entry = NULL;
 100                         if (clip_vcc->xoff)
 101                                 netif_wake_queue(entry->neigh->dev);
 102                         if (entry->vccs)
 103                                 goto out;
 104                         entry->expires = jiffies - 1;
 105                         /* force resolution or expiration */
 106                         error = neigh_update(entry->neigh, NULL, NUD_NONE,
 107                                              NEIGH_UPDATE_F_ADMIN);
 108                         if (error)
 109                                 printk(KERN_CRIT "unlink_clip_vcc: "
 110                                        "neigh_update failed with %d\n", error);
 111                         goto out;
 112                 }
 113         printk(KERN_CRIT "ATMARP: unlink_clip_vcc failed (entry %p, vcc "
 114                "0x%p)\n", entry, clip_vcc);
 115       out:
 116         netif_tx_unlock_bh(entry->neigh->dev);
 117 }
 118
 119 /* The neighbour entry n->lock is held. */
 120 static int neigh_check_cb(struct neighbour *n)
 121 {
 122         struct atmarp_entry *entry = NEIGH2ENTRY(n);
 123         struct clip_vcc *cv;
 124
 125         for (cv = entry->vccs; cv; cv = cv->next) {
 126                 unsigned long exp = cv->last_use + cv->idle_timeout;
 127
 128                 if (cv->idle_timeout && time_after(jiffies, exp)) {
 129                         pr_debug("releasing vcc %p->%p of entry %p\n",
 130                                 cv, cv->vcc, entry);
 131                         vcc_release_async(cv->vcc, -ETIMEDOUT);
 132                 }
 133         }
 134
 135         if (entry->vccs || time_before(jiffies, entry->expires))
 136                 return 0;
 137
 138         if (atomic_read(&n->refcnt) > 1) {
 139                 struct sk_buff *skb;
 140
 141                 pr_debug("destruction postponed with ref %d\n",
 142                         atomic_read(&n->refcnt));
 143
 144                 while ((skb = skb_dequeue(&n->arp_queue)) != NULL)
 145                         dev_kfree_skb(skb);
 146
 147                 return 0;
 148         }
 149
 150         pr_debug("expired neigh %p\n", n);
 151         return 1;
 152 }
 153
 154 static void idle_timer_check(unsigned long dummy)
 155 {
 156         write_lock(&clip_tbl.lock);
 157         __neigh_for_each_release(&clip_tbl, neigh_check_cb);
 158         mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
 159         write_unlock(&clip_tbl.lock);
 160 }
 161
 162 static int clip_arp_rcv(struct sk_buff *skb)
 163 {
 164         struct atm_vcc *vcc;
 165
 166         pr_debug("clip_arp_rcv\n");
 167         vcc = ATM_SKB(skb)->vcc;
 168         if (!vcc || !atm_charge(vcc, skb->truesize)) {
 169                 dev_kfree_skb_any(skb);
 170                 return 0;
 171         }
 172         pr_debug("pushing to %p\n", vcc);
 173         pr_debug("using %p\n", CLIP_VCC(vcc)->old_push);
 174         CLIP_VCC(vcc)->old_push(vcc, skb);
 175         return 0;
 176 }
 177
 178 static const unsigned char llc_oui[] = {
 179         0xaa,   /* DSAP: non-ISO */
 180         0xaa,   /* SSAP: non-ISO */
 181         0x03,   /* Ctrl: Unnumbered Information Command PDU */
 182         0x00,   /* OUI: EtherType */
 183         0x00,
 184         0x00
 185 };
 186
 187 static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb)
 188 {
 189         struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
 190
 191         pr_debug("clip push\n");
 192         if (!skb) {
 193                 pr_debug("removing VCC %p\n", clip_vcc);
 194                 if (clip_vcc->entry)
 195                         unlink_clip_vcc(clip_vcc);
 196                 clip_vcc->old_push(vcc, NULL);  /* pass on the bad news */
 197                 kfree(clip_vcc);
 198                 return;
 199         }
 200         atm_return(vcc, skb->truesize);
 201         skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
 202         /* clip_vcc->entry == NULL if we don't have an IP address yet */
 203         if (!skb->dev) {
 204                 dev_kfree_skb_any(skb);
 205                 return;
 206         }
 207         ATM_SKB(skb)->vcc = vcc;
 208         skb_reset_mac_header(skb);
 209         if (!clip_vcc->encap
 210             || skb->len < RFC1483LLC_LEN
 211             || memcmp(skb->data, llc_oui, sizeof (llc_oui)))
 212                 skb->protocol = htons(ETH_P_IP);
 213         else {
 214                 skb->protocol = ((__be16 *) skb->data)[3];
 215                 skb_pull(skb, RFC1483LLC_LEN);
 216                 if (skb->protocol == htons(ETH_P_ARP)) {
 217                         PRIV(skb->dev)->stats.rx_packets++;
 218                         PRIV(skb->dev)->stats.rx_bytes += skb->len;
 219                         clip_arp_rcv(skb);
 220                         return;
 221                 }
 222         }
 223         clip_vcc->last_use = jiffies;
 224         PRIV(skb->dev)->stats.rx_packets++;
 225         PRIV(skb->dev)->stats.rx_bytes += skb->len;
 226         memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
 227         netif_rx(skb);
 228 }
 229
 230 /*
 231  * Note: these spinlocks _must_not_ block on non-SMP. The only goal is that
 232  * clip_pop is atomic with respect to the critical section in clip_start_xmit.
 233  */
 234
 235 static void clip_pop(struct atm_vcc *vcc, struct sk_buff *skb)
 236 {
 237         struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
 238         struct net_device *dev = skb->dev;
 239         int old;
 240         unsigned long flags;
 241
 242         pr_debug("clip_pop(vcc %p)\n", vcc);
 243         clip_vcc->old_pop(vcc, skb);
 244         /* skb->dev == NULL in outbound ARP packets */
 245         if (!dev)
 246                 return;
 247         spin_lock_irqsave(&PRIV(dev)->xoff_lock, flags);
 248         if (atm_may_send(vcc, 0)) {
 249                 old = xchg(&clip_vcc->xoff, 0);
 250                 if (old)
 251                         netif_wake_queue(dev);
 252         }
 253         spin_unlock_irqrestore(&PRIV(dev)->xoff_lock, flags);
 254 }
 255
 256 static void clip_neigh_solicit(struct neighbour *neigh, struct sk_buff *skb)
 257 {
 258         pr_debug("clip_neigh_solicit (neigh %p, skb %p)\n", neigh, skb);
 259         to_atmarpd(act_need, PRIV(neigh->dev)->number, NEIGH2ENTRY(neigh)->ip);
 260 }
 261
 262 static void clip_neigh_error(struct neighbour *neigh, struct sk_buff *skb)
 263 {
 264 #ifndef CONFIG_ATM_CLIP_NO_ICMP
 265         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
 266 #endif
 267         kfree_skb(skb);
 268 }
 269
 270 static struct neigh_ops clip_neigh_ops = {
 271         .family =               AF_INET,
 272         .solicit =              clip_neigh_solicit,
 273         .error_report =         clip_neigh_error,
 274         .output =               dev_queue_xmit,
 275         .connected_output =     dev_queue_xmit,
 276         .hh_output =            dev_queue_xmit,
 277         .queue_xmit =           dev_queue_xmit,
 278 };
 279
 280 static int clip_constructor(struct neighbour *neigh)
 281 {
 282         struct atmarp_entry *entry = NEIGH2ENTRY(neigh);
 283         struct net_device *dev = neigh->dev;
 284         struct in_device *in_dev;
 285         struct neigh_parms *parms;
 286
 287         pr_debug("clip_constructor (neigh %p, entry %p)\n", neigh, entry);
 288         neigh->type = inet_addr_type(&init_net, entry->ip);
 289         if (neigh->type != RTN_UNICAST)
 290                 return -EINVAL;
 291
 292         rcu_read_lock();
 293         in_dev = __in_dev_get_rcu(dev);
 294         if (!in_dev) {
 295                 rcu_read_unlock();
 296                 return -EINVAL;
 297         }
 298
 299         parms = in_dev->arp_parms;
 300         __neigh_parms_put(neigh->parms);
 301         neigh->parms = neigh_parms_clone(parms);
 302         rcu_read_unlock();
 303
 304         neigh->ops = &clip_neigh_ops;
 305         neigh->output = neigh->nud_state & NUD_VALID ?
 306             neigh->ops->connected_output : neigh->ops->output;
 307         entry->neigh = neigh;
 308         entry->vccs = NULL;
 309         entry->expires = jiffies - 1;
 310         return 0;
 311 }
 312
 313 static u32 clip_hash(const void *pkey, const struct net_device *dev)
 314 {
 315         return jhash_2words(*(u32 *) pkey, dev->ifindex, clip_tbl.hash_rnd);
 316 }
 317
 318 static struct neigh_table clip_tbl = {
 319         .family         = AF_INET,
 320         .entry_size     = sizeof(struct neighbour)+sizeof(struct atmarp_entry),
 321         .key_len        = 4,
 322         .hash           = clip_hash,
 323         .constructor    = clip_constructor,
 324         .id             = "clip_arp_cache",
 325
 326         /* parameters are copied from ARP ... */
 327         .parms = {
 328                 .tbl                    = &clip_tbl,
 329                 .base_reachable_time    = 30 * HZ,
 330                 .retrans_time           = 1 * HZ,
 331                 .gc_staletime           = 60 * HZ,
 332                 .reachable_time         = 30 * HZ,
 333                 .delay_probe_time       = 5 * HZ,
 334                 .queue_len              = 3,
 335                 .ucast_probes           = 3,
 336                 .mcast_probes           = 3,
 337                 .anycast_delay          = 1 * HZ,
 338                 .proxy_delay            = (8 * HZ) / 10,
 339                 .proxy_qlen             = 64,
 340                 .locktime               = 1 * HZ,
 341         },
 342         .gc_interval    = 30 * HZ,
 343         .gc_thresh1     = 128,
 344         .gc_thresh2     = 512,
 345         .gc_thresh3     = 1024,
 346 };
 347
 348 /* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */
 349
 350 /*
 351  * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
 352  * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
 353  * don't increment the usage count. This is used to create entries in
 354  * clip_setentry.
 355  */
 356
 357 static int clip_encap(struct atm_vcc *vcc, int mode)
 358 {
 359         CLIP_VCC(vcc)->encap = mode;
 360         return 0;
 361 }
 362
 363 static int clip_start_xmit(struct sk_buff *skb, struct net_device *dev)
 364 {
 365         struct clip_priv *clip_priv = PRIV(dev);
 366         struct atmarp_entry *entry;
 367         struct atm_vcc *vcc;
 368         int old;
 369         unsigned long flags;
 370
 371         pr_debug("clip_start_xmit (skb %p)\n", skb);
 372         if (!skb->dst) {
 373                 printk(KERN_ERR "clip_start_xmit: skb->dst == NULL\n");
 374                 dev_kfree_skb(skb);
 375                 clip_priv->stats.tx_dropped++;
 376                 return 0;
 377         }
 378         if (!skb->dst->neighbour) {
 379 #if 0
 380                 skb->dst->neighbour = clip_find_neighbour(skb->dst, 1);
 381                 if (!skb->dst->neighbour) {
 382                         dev_kfree_skb(skb);     /* lost that one */
 383                         clip_priv->stats.tx_dropped++;
 384                         return 0;
 385                 }
 386 #endif
 387                 printk(KERN_ERR "clip_start_xmit: NO NEIGHBOUR !\n");
 388                 dev_kfree_skb(skb);
 389                 clip_priv->stats.tx_dropped++;
 390                 return 0;
 391         }
 392         entry = NEIGH2ENTRY(skb->dst->neighbour);
 393         if (!entry->vccs) {
 394                 if (time_after(jiffies, entry->expires)) {
 395                         /* should be resolved */
 396                         entry->expires = jiffies + ATMARP_RETRY_DELAY * HZ;
 397                         to_atmarpd(act_need, PRIV(dev)->number, entry->ip);
 398                 }
 399                 if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
 400                         skb_queue_tail(&entry->neigh->arp_queue, skb);
 401                 else {
 402                         dev_kfree_skb(skb);
 403                         clip_priv->stats.tx_dropped++;
 404                 }
 405                 return 0;
 406         }
 407         pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
 408         ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
 409         pr_debug("using neighbour %p, vcc %p\n", skb->dst->neighbour, vcc);
 410         if (entry->vccs->encap) {
 411                 void *here;
 412
 413                 here = skb_push(skb, RFC1483LLC_LEN);
 414                 memcpy(here, llc_oui, sizeof(llc_oui));
 415                 ((__be16 *) here)[3] = skb->protocol;
 416         }
 417         atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
 418         ATM_SKB(skb)->atm_options = vcc->atm_options;
 419         entry->vccs->last_use = jiffies;
 420         pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
 421         old = xchg(&entry->vccs->xoff, 1);      /* assume XOFF ... */
 422         if (old) {
 423                 printk(KERN_WARNING "clip_start_xmit: XOFF->XOFF transition\n");
 424                 return 0;
 425         }
 426         clip_priv->stats.tx_packets++;
 427         clip_priv->stats.tx_bytes += skb->len;
 428         vcc->send(vcc, skb);
 429         if (atm_may_send(vcc, 0)) {
 430                 entry->vccs->xoff = 0;
 431                 return 0;
 432         }
 433         spin_lock_irqsave(&clip_priv->xoff_lock, flags);
 434         netif_stop_queue(dev);  /* XOFF -> throttle immediately */
 435         barrier();
 436         if (!entry->vccs->xoff)
 437                 netif_start_queue(dev);
 438         /* Oh, we just raced with clip_pop. netif_start_queue should be
 439            good enough, because nothing should really be asleep because
 440            of the brief netif_stop_queue. If this isn't true or if it
 441            changes, use netif_wake_queue instead. */
 442         spin_unlock_irqrestore(&clip_priv->xoff_lock, flags);
 443         return 0;
 444 }
 445
 446 static struct net_device_stats *clip_get_stats(struct net_device *dev)
 447 {
 448         return &PRIV(dev)->stats;
 449 }
 450
 451 static int clip_mkip(struct atm_vcc *vcc, int timeout)
 452 {
 453         struct clip_vcc *clip_vcc;
 454         struct sk_buff *skb;
 455         struct sk_buff_head *rq;
 456         unsigned long flags;
 457
 458         if (!vcc->push)
 459                 return -EBADFD;
 460         clip_vcc = kmalloc(sizeof(struct clip_vcc), GFP_KERNEL);
 461         if (!clip_vcc)
 462                 return -ENOMEM;
 463         pr_debug("mkip clip_vcc %p vcc %p\n", clip_vcc, vcc);
 464         clip_vcc->vcc = vcc;
 465         vcc->user_back = clip_vcc;
 466         set_bit(ATM_VF_IS_CLIP, &vcc->flags);
 467         clip_vcc->entry = NULL;
 468         clip_vcc->xoff = 0;
 469         clip_vcc->encap = 1;
 470         clip_vcc->last_use = jiffies;
 471         clip_vcc->idle_timeout = timeout * HZ;
 472         clip_vcc->old_push = vcc->push;
 473         clip_vcc->old_pop = vcc->pop;
 474         vcc->push = clip_push;
 475         vcc->pop = clip_pop;
 476
 477         rq = &sk_atm(vcc)->sk_receive_queue;
 478
 479         spin_lock_irqsave(&rq->lock, flags);
 480         if (skb_queue_empty(rq)) {
 481                 skb = NULL;
 482         } else {
 483                 /* NULL terminate the list.  */
 484                 rq->prev->next = NULL;
 485                 skb = rq->next;
 486         }
 487         rq->prev = rq->next = (struct sk_buff *)rq;
 488         rq->qlen = 0;
 489         spin_unlock_irqrestore(&rq->lock, flags);
 490
 491         /* re-process everything received between connection setup and MKIP */
 492         while (skb) {
 493                 struct sk_buff *next = skb->next;
 494
 495                 skb->next = skb->prev = NULL;
 496                 if (!clip_devs) {
 497                         atm_return(vcc, skb->truesize);
 498                         kfree_skb(skb);
 499                 } else {
 500                         unsigned int len = skb->len;
 501
 502                         skb_get(skb);
 503                         clip_push(vcc, skb);
 504                         PRIV(skb->dev)->stats.rx_packets--;
 505                         PRIV(skb->dev)->stats.rx_bytes -= len;
 506                         kfree_skb(skb);
 507                 }
 508
 509                 skb = next;
 510         }
 511         return 0;
 512 }
 513
 514 static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
 515 {
 516         struct neighbour *neigh;
 517         struct atmarp_entry *entry;
 518         int error;
 519         struct clip_vcc *clip_vcc;
 520         struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, .tos = 1}} };
 521         struct rtable *rt;
 522
 523         if (vcc->push != clip_push) {
 524                 printk(KERN_WARNING "clip_setentry: non-CLIP VCC\n");
 525                 return -EBADF;
 526         }
 527         clip_vcc = CLIP_VCC(vcc);
 528         if (!ip) {
 529                 if (!clip_vcc->entry) {
 530                         printk(KERN_ERR "hiding hidden ATMARP entry\n");
 531                         return 0;
 532                 }
 533                 pr_debug("setentry: remove\n");
 534                 unlink_clip_vcc(clip_vcc);
 535                 return 0;
 536         }
 537         error = ip_route_output_key(&init_net, &rt, &fl);
 538         if (error)
 539                 return error;
 540         neigh = __neigh_lookup(&clip_tbl, &ip, rt->u.dst.dev, 1);
 541         ip_rt_put(rt);
 542         if (!neigh)
 543                 return -ENOMEM;
 544         entry = NEIGH2ENTRY(neigh);
 545         if (entry != clip_vcc->entry) {
 546                 if (!clip_vcc->entry)
 547                         pr_debug("setentry: add\n");
 548                 else {
 549                         pr_debug("setentry: update\n");
 550                         unlink_clip_vcc(clip_vcc);
 551                 }
 552                 link_vcc(clip_vcc, entry);
 553         }
 554         error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
 555                              NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
 556         neigh_release(neigh);
 557         return error;
 558 }
 559
 560 static void clip_setup(struct net_device *dev)
 561 {
 562         dev->hard_start_xmit = clip_start_xmit;
 563         /* sg_xmit ... */
 564         dev->get_stats = clip_get_stats;
 565         dev->type = ARPHRD_ATM;
 566         dev->hard_header_len = RFC1483LLC_LEN;
 567         dev->mtu = RFC1626_MTU;
 568         dev->tx_queue_len = 100;        /* "normal" queue (packets) */
 569         /* When using a "real" qdisc, the qdisc determines the queue */
 570         /* length. tx_queue_len is only used for the default case, */
 571         /* without any more elaborate queuing. 100 is a reasonable */
 572         /* compromise between decent burst-tolerance and protection */
 573         /* against memory hogs. */
 574 }
 575
 576 static int clip_create(int number)
 577 {
 578         struct net_device *dev;
 579         struct clip_priv *clip_priv;
 580         int error;
 581
 582         if (number != -1) {
 583                 for (dev = clip_devs; dev; dev = PRIV(dev)->next)
 584                         if (PRIV(dev)->number == number)
 585                                 return -EEXIST;
 586         } else {
 587                 number = 0;
 588                 for (dev = clip_devs; dev; dev = PRIV(dev)->next)
 589                         if (PRIV(dev)->number >= number)
 590                                 number = PRIV(dev)->number + 1;
 591         }
 592         dev = alloc_netdev(sizeof(struct clip_priv), "", clip_setup);
 593         if (!dev)
 594                 return -ENOMEM;
 595         clip_priv = PRIV(dev);
 596         sprintf(dev->name, "atm%d", number);
 597         spin_lock_init(&clip_priv->xoff_lock);
 598         clip_priv->number = number;
 599         error = register_netdev(dev);
 600         if (error) {
 601                 free_netdev(dev);
 602                 return error;
 603         }
 604         clip_priv->next = clip_devs;
 605         clip_devs = dev;
 606         pr_debug("registered (net:%s)\n", dev->name);
 607         return number;
 608 }
 609
 610 static int clip_device_event(struct notifier_block *this, unsigned long event,
 611                              void *arg)
 612 {
 613         struct net_device *dev = arg;
 614
 615         if (!net_eq(dev_net(dev), &init_net))
 616                 return NOTIFY_DONE;
 617
 618         if (event == NETDEV_UNREGISTER) {
 619                 neigh_ifdown(&clip_tbl, dev);
 620                 return NOTIFY_DONE;
 621         }
 622
 623         /* ignore non-CLIP devices */
 624         if (dev->type != ARPHRD_ATM || dev->hard_start_xmit != clip_start_xmit)
 625                 return NOTIFY_DONE;
 626
 627         switch (event) {
 628         case NETDEV_UP:
 629                 pr_debug("clip_device_event NETDEV_UP\n");
 630                 to_atmarpd(act_up, PRIV(dev)->number, 0);
 631                 break;
 632         case NETDEV_GOING_DOWN:
 633                 pr_debug("clip_device_event NETDEV_DOWN\n");
 634                 to_atmarpd(act_down, PRIV(dev)->number, 0);
 635                 break;
 636         case NETDEV_CHANGE:
 637         case NETDEV_CHANGEMTU:
 638                 pr_debug("clip_device_event NETDEV_CHANGE*\n");
 639                 to_atmarpd(act_change, PRIV(dev)->number, 0);
 640                 break;
 641         }
 642         return NOTIFY_DONE;
 643 }
 644
 645 static int clip_inet_event(struct notifier_block *this, unsigned long event,
 646                            void *ifa)
 647 {
 648         struct in_device *in_dev;
 649
 650         in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
 651         /*
 652          * Transitions are of the down-change-up type, so it's sufficient to
 653          * handle the change on up.
 654          */
 655         if (event != NETDEV_UP)
 656                 return NOTIFY_DONE;
 657         return clip_device_event(this, NETDEV_CHANGE, in_dev->dev);
 658 }
 659
 660
 661 static struct notifier_block clip_dev_notifier = {
 662         .notifier_call = clip_device_event,
 663 };
 664
 665
 666
 667 static struct notifier_block clip_inet_notifier = {
 668         .notifier_call = clip_inet_event,
 669 };
 670
 671
 672
 673 static void atmarpd_close(struct atm_vcc *vcc)
 674 {
 675         pr_debug("atmarpd_close\n");
 676
 677         rtnl_lock();
 678         atmarpd = NULL;
 679         skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
 680         rtnl_unlock();
 681
 682         pr_debug("(done)\n");
 683         module_put(THIS_MODULE);
 684 }
 685
 686
 687 static struct atmdev_ops atmarpd_dev_ops = {
 688         .close = atmarpd_close
 689 };
 690
 691
 692 static struct atm_dev atmarpd_dev = {
 693         .ops =                  &atmarpd_dev_ops,
 694         .type =                 "arpd",
 695         .number =               999,
 696         .lock =                 __SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
 697 };
 698
 699
 700 static int atm_init_atmarp(struct atm_vcc *vcc)
 701 {
 702         rtnl_lock();
 703         if (atmarpd) {
 704                 rtnl_unlock();
 705                 return -EADDRINUSE;
 706         }
 707
 708         mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);
 709
 710         atmarpd = vcc;
 711         set_bit(ATM_VF_META,&vcc->flags);
 712         set_bit(ATM_VF_READY,&vcc->flags);
 713             /* allow replies and avoid getting closed if signaling dies */
 714         vcc->dev = &atmarpd_dev;
 715         vcc_insert_socket(sk_atm(vcc));
 716         vcc->push = NULL;
 717         vcc->pop = NULL; /* crash */
 718         vcc->push_oam = NULL; /* crash */
 719         rtnl_unlock();
 720         return 0;
 721 }
 722
 723 static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 724 {
 725         struct atm_vcc *vcc = ATM_SD(sock);
 726         int err = 0;
 727
 728         switch (cmd) {
 729         case SIOCMKCLIP:
 730         case ATMARPD_CTRL:
 731         case ATMARP_MKIP:
 732         case ATMARP_SETENTRY:
 733         case ATMARP_ENCAP:
 734                 if (!capable(CAP_NET_ADMIN))
 735                         return -EPERM;
 736                 break;
 737         default:
 738                 return -ENOIOCTLCMD;
 739         }
 740
 741         switch (cmd) {
 742         case SIOCMKCLIP:
 743                 err = clip_create(arg);
 744                 break;
 745         case ATMARPD_CTRL:
 746                 err = atm_init_atmarp(vcc);
 747                 if (!err) {
 748                         sock->state = SS_CONNECTED;
 749                         __module_get(THIS_MODULE);
 750                 }
 751                 break;
 752         case ATMARP_MKIP:
 753                 err = clip_mkip(vcc, arg);
 754                 break;
 755         case ATMARP_SETENTRY:
 756                 err = clip_setentry(vcc, (__force __be32)arg);
 757                 break;
 758         case ATMARP_ENCAP:
 759                 err = clip_encap(vcc, arg);
 760                 break;
 761         }
 762         return err;
 763 }
 764
 765 static struct atm_ioctl clip_ioctl_ops = {
 766         .owner = THIS_MODULE,
 767         .ioctl = clip_ioctl,
 768 };
 769
 770 #ifdef CONFIG_PROC_FS
 771
 772 static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
 773 {
 774         static int code[] = { 1, 2, 10, 6, 1, 0 };
 775         static int e164[] = { 1, 8, 4, 6, 1, 0 };
 776
 777         if (*addr->sas_addr.pub) {
 778                 seq_printf(seq, "%s", addr->sas_addr.pub);
 779                 if (*addr->sas_addr.prv)
 780                         seq_putc(seq, '+');
 781         } else if (!*addr->sas_addr.prv) {
 782                 seq_printf(seq, "%s", "(none)");
 783                 return;
 784         }
 785         if (*addr->sas_addr.prv) {
 786                 unsigned char *prv = addr->sas_addr.prv;
 787                 int *fields;
 788                 int i, j;
 789
 790                 fields = *prv == ATM_AFI_E164 ? e164 : code;
 791                 for (i = 0; fields[i]; i++) {
 792                         for (j = fields[i]; j; j--)
 793                                 seq_printf(seq, "%02X", *prv++);
 794                         if (fields[i + 1])
 795                                 seq_putc(seq, '.');
 796                 }
 797         }
 798 }
 799
 800 /* This means the neighbour entry has no attached VCC objects. */
 801 #define SEQ_NO_VCC_TOKEN        ((void *) 2)
 802
 803 static void atmarp_info(struct seq_file *seq, struct net_device *dev,
 804                         struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
 805 {
 806         unsigned long exp;
 807         char buf[17];
 808         int svc, llc, off;
 809
 810         svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
 811                (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));
 812
 813         llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);
 814
 815         if (clip_vcc == SEQ_NO_VCC_TOKEN)
 816                 exp = entry->neigh->used;
 817         else
 818                 exp = clip_vcc->last_use;
 819
 820         exp = (jiffies - exp) / HZ;
 821
 822         seq_printf(seq, "%-6s%-4s%-4s%5ld ",
 823                    dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);
 824
 825         off = scnprintf(buf, sizeof(buf) - 1, "%d.%d.%d.%d",
 826                         NIPQUAD(entry->ip));
 827         while (off < 16)
 828                 buf[off++] = ' ';
 829         buf[off] = '\0';
 830         seq_printf(seq, "%s", buf);
 831
 832         if (clip_vcc == SEQ_NO_VCC_TOKEN) {
 833                 if (time_before(jiffies, entry->expires))
 834                         seq_printf(seq, "(resolving)\n");
 835                 else
 836                         seq_printf(seq, "(expired, ref %d)\n",
 837                                    atomic_read(&entry->neigh->refcnt));
 838         } else if (!svc) {
 839                 seq_printf(seq, "%d.%d.%d\n",
 840                            clip_vcc->vcc->dev->number,
 841                            clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
 842         } else {
 843                 svc_addr(seq, &clip_vcc->vcc->remote);
 844                 seq_putc(seq, '\n');
 845         }
 846 }
 847
 848 struct clip_seq_state {
 849         /* This member must be first. */
 850         struct neigh_seq_state ns;
 851
 852         /* Local to clip specific iteration. */
 853         struct clip_vcc *vcc;
 854 };
 855
 856 static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
 857                                           struct clip_vcc *curr)
 858 {
 859         if (!curr) {
 860                 curr = e->vccs;
 861                 if (!curr)
 862                         return SEQ_NO_VCC_TOKEN;
 863                 return curr;
 864         }
 865         if (curr == SEQ_NO_VCC_TOKEN)
 866                 return NULL;
 867
 868         curr = curr->next;
 869
 870         return curr;
 871 }
 872
 873 static void *clip_seq_vcc_walk(struct clip_seq_state *state,
 874                                struct atmarp_entry *e, loff_t * pos)
 875 {
 876         struct clip_vcc *vcc = state->vcc;
 877
 878         vcc = clip_seq_next_vcc(e, vcc);
 879         if (vcc && pos != NULL) {
 880                 while (*pos) {
 881                         vcc = clip_seq_next_vcc(e, vcc);
 882                         if (!vcc)
 883                                 break;
 884                         --(*pos);
 885                 }
 886         }
 887         state->vcc = vcc;
 888
 889         return vcc;
 890 }
 891
 892 static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
 893                                struct neighbour *n, loff_t * pos)
 894 {
 895         struct clip_seq_state *state = (struct clip_seq_state *)_state;
 896
 897         return clip_seq_vcc_walk(state, NEIGH2ENTRY(n), pos);
 898 }
 899
 900 static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
 901 {
 902         struct clip_seq_state *state = seq->private;
 903         state->ns.neigh_sub_iter = clip_seq_sub_iter;
 904         return neigh_seq_start(seq, pos, &clip_tbl, NEIGH_SEQ_NEIGH_ONLY);
 905 }
 906
 907 static int clip_seq_show(struct seq_file *seq, void *v)
 908 {
 909         static char atm_arp_banner[] =
 910             "IPitf TypeEncp Idle IP address      ATM address\n";
 911
 912         if (v == SEQ_START_TOKEN) {
 913                 seq_puts(seq, atm_arp_banner);
 914         } else {
 915                 struct clip_seq_state *state = seq->private;
 916                 struct neighbour *n = v;
 917                 struct clip_vcc *vcc = state->vcc;
 918
 919                 atmarp_info(seq, n->dev, NEIGH2ENTRY(n), vcc);
 920         }
 921         return 0;
 922 }
 923
 924 static const struct seq_operations arp_seq_ops = {
 925         .start  = clip_seq_start,
 926         .next   = neigh_seq_next,
 927         .stop   = neigh_seq_stop,
 928         .show   = clip_seq_show,
 929 };
 930
 931 static int arp_seq_open(struct inode *inode, struct file *file)
 932 {
 933         return seq_open_net(inode, file, &arp_seq_ops,
 934                             sizeof(struct clip_seq_state));
 935 }
 936
 937 static const struct file_operations arp_seq_fops = {
 938         .open           = arp_seq_open,
 939         .read           = seq_read,
 940         .llseek         = seq_lseek,
 941         .release        = seq_release_net,
 942         .owner          = THIS_MODULE
 943 };
 944 #endif
 945
 946 static void atm_clip_exit_noproc(void);
 947
 948 static int __init atm_clip_init(void)
 949 {
 950         neigh_table_init_no_netlink(&clip_tbl);
 951
 952         clip_tbl_hook = &clip_tbl;
 953         register_atm_ioctl(&clip_ioctl_ops);
 954         register_netdevice_notifier(&clip_dev_notifier);
 955         register_inetaddr_notifier(&clip_inet_notifier);
 956
 957         setup_timer(&idle_timer, idle_timer_check, 0);
 958
 959 #ifdef CONFIG_PROC_FS
 960         {
 961                 struct proc_dir_entry *p;
 962
 963                 p = proc_create("arp", S_IRUGO, atm_proc_root, &arp_seq_fops);
 964                 if (!p) {
 965                         printk(KERN_ERR "Unable to initialize "
 966                                "/proc/net/atm/arp\n");
 967                         atm_clip_exit_noproc();
 968                         return -ENOMEM;
 969                 }
 970         }
 971 #endif
 972
 973         return 0;
 974 }
 975
 976 static void atm_clip_exit_noproc(void)
 977 {
 978         struct net_device *dev, *next;
 979
 980         unregister_inetaddr_notifier(&clip_inet_notifier);
 981         unregister_netdevice_notifier(&clip_dev_notifier);
 982
 983         deregister_atm_ioctl(&clip_ioctl_ops);
 984
 985         /* First, stop the idle timer, so it stops banging
 986          * on the table.
 987          */
 988         del_timer_sync(&idle_timer);
 989
 990         /* Next, purge the table, so that the device
 991          * unregister loop below does not hang due to
 992          * device references remaining in the table.
 993          */
 994         neigh_ifdown(&clip_tbl, NULL);
 995
 996         dev = clip_devs;
 997         while (dev) {
 998                 next = PRIV(dev)->next;
 999                 unregister_netdev(dev);
1000                 free_netdev(dev);
1001                 dev = next;
1002         }
1003
1004         /* Now it is safe to fully shutdown whole table. */
1005         neigh_table_clear(&clip_tbl);
1006
1007         clip_tbl_hook = NULL;
1008 }
1009
1010 static void __exit atm_clip_exit(void)
1011 {
1012         remove_proc_entry("arp", atm_proc_root);
1013
1014         atm_clip_exit_noproc();
1015 }
1016
1017 module_init(atm_clip_init);
1018 module_exit(atm_clip_exit);
1019 MODULE_AUTHOR("Werner Almesberger");
1020 MODULE_DESCRIPTION("Classical/IP over ATM interface");
1021 MODULE_LICENSE("GPL");