net/atm/br2684.c

   1 /*
   2 Experimental ethernet netdevice using ATM AAL5 as underlying carrier
   3 (RFC1483 obsoleted by RFC2684) for Linux 2.4
   4 Author: Marcell GAL, 2000, XDSL Ltd, Hungary
   5 */
   6
   7 #include <linux/module.h>
   8 #include <linux/config.h>
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/list.h>
  12 #include <linux/netdevice.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/rtnetlink.h>
  16 #include <linux/ip.h>
  17 #include <asm/uaccess.h>
  18 #include <net/arp.h>
  19 #include <linux/atm.h>
  20 #include <linux/atmdev.h>
  21
  22 #include <linux/atmbr2684.h>
  23
  24 #include "common.h"
  25 #include "ipcommon.h"
  26
  27 /*
  28  * Define this to use a version of the code which interacts with the higher
  29  * layers in a more intellegent way, by always reserving enough space for
  30  * our header at the begining of the packet.  However, there may still be
  31  * some problems with programs like tcpdump.  In 2.5 we'll sort out what
  32  * we need to do to get this perfect.  For now we just will copy the packet
  33  * if we need space for the header
  34  */
  35 /* #define FASTER_VERSION */
  36
  37 #ifdef DEBUG
  38 #define DPRINTK(format, args...) printk(KERN_DEBUG "br2684: " format, ##args)
  39 #else
  40 #define DPRINTK(format, args...)
  41 #endif
  42
  43 #ifdef SKB_DEBUG
  44 static void skb_debug(const struct sk_buff *skb)
  45 {
  46 #define NUM2PRINT 50
  47         char buf[NUM2PRINT * 3 + 1];    /* 3 chars per byte */
  48         int i = 0;
  49         for (i = 0; i < skb->len && i < NUM2PRINT; i++) {
  50                 sprintf(buf + i * 3, "%2.2x ", 0xff & skb->data[i]);
  51         }
  52         printk(KERN_DEBUG "br2684: skb: %s\n", buf);
  53 }
  54 #else
  55 #define skb_debug(skb)  do {} while (0)
  56 #endif
  57
  58 static unsigned char llc_oui_pid_pad[] =
  59     { 0xAA, 0xAA, 0x03, 0x00, 0x80, 0xC2, 0x00, 0x07, 0x00, 0x00 };
  60 #define PADLEN  (2)
  61
  62 enum br2684_encaps {
  63         e_vc  = BR2684_ENCAPS_VC,
  64         e_llc = BR2684_ENCAPS_LLC,
  65 };
  66
  67 struct br2684_vcc {
  68         struct atm_vcc  *atmvcc;
  69         struct br2684_dev *brdev;
  70         /* keep old push,pop functions for chaining */
  71         void (*old_push)(struct atm_vcc *vcc,struct sk_buff *skb);
  72         /* void (*old_pop)(struct atm_vcc *vcc,struct sk_buff *skb); */
  73         enum br2684_encaps encaps;
  74         struct list_head brvccs;
  75 #ifdef CONFIG_ATM_BR2684_IPFILTER
  76         struct br2684_filter filter;
  77 #endif /* CONFIG_ATM_BR2684_IPFILTER */
  78 #ifndef FASTER_VERSION
  79         unsigned copies_needed, copies_failed;
  80 #endif /* FASTER_VERSION */
  81 };
  82
  83 struct br2684_dev {
  84         struct net_device net_dev;
  85         struct list_head br2684_devs;
  86         int number;
  87         struct list_head brvccs; /* one device <=> one vcc (before xmas) */
  88         struct net_device_stats stats;
  89         int mac_was_set;
  90 };
  91
  92 /*
  93  * This lock should be held for writing any time the list of devices or
  94  * their attached vcc's could be altered.  It should be held for reading
  95  * any time these are being queried.  Note that we sometimes need to
  96  * do read-locking under interrupt context, so write locking must block
  97  * the current CPU's interrupts
  98  */
  99 static rwlock_t devs_lock = RW_LOCK_UNLOCKED;
 100
 101 static LIST_HEAD(br2684_devs);
 102
 103 static inline struct br2684_dev *BRPRIV(const struct net_device *net_dev)
 104 {
 105         return (struct br2684_dev *) ((char *) (net_dev) -
 106             (unsigned long) (&((struct br2684_dev *) 0)->net_dev));
 107 }
 108
 109 static inline struct br2684_dev *list_entry_brdev(const struct list_head *le)
 110 {
 111         return list_entry(le, struct br2684_dev, br2684_devs);
 112 }
 113
 114 static inline struct br2684_vcc *BR2684_VCC(const struct atm_vcc *atmvcc)
 115 {
 116         return (struct br2684_vcc *) (atmvcc->user_back);
 117 }
 118
 119 static inline struct br2684_vcc *list_entry_brvcc(const struct list_head *le)
 120 {
 121         return list_entry(le, struct br2684_vcc, brvccs);
 122 }
 123
 124 /* Caller should hold read_lock(&devs_lock) */
 125 static struct br2684_dev *br2684_find_dev(const struct br2684_if_spec *s)
 126 {
 127         struct list_head *lh;
 128         struct br2684_dev *brdev;
 129         switch (s->method) {
 130         case BR2684_FIND_BYNUM:
 131                 list_for_each(lh, &br2684_devs) {
 132                         brdev = list_entry_brdev(lh);
 133                         if (brdev->number == s->spec.devnum)
 134                                 return brdev;
 135                 }
 136                 break;
 137         case BR2684_FIND_BYIFNAME:
 138                 list_for_each(lh, &br2684_devs) {
 139                         brdev = list_entry_brdev(lh);
 140                         if (!strncmp(brdev->net_dev.name, s->spec.ifname,
 141                             sizeof brdev->net_dev.name))
 142                                 return brdev;
 143                 }
 144                 break;
 145         }
 146         return NULL;
 147 }
 148
 149 /*
 150  * Send a packet out a particular vcc.  Not to useful right now, but paves
 151  * the way for multiple vcc's per itf.  Returns true if we can send,
 152  * otherwise false
 153  */
 154 static int br2684_xmit_vcc(struct sk_buff *skb, struct br2684_dev *brdev,
 155         struct br2684_vcc *brvcc)
 156 {
 157         struct atm_vcc *atmvcc;
 158 #ifdef FASTER_VERSION
 159         if (brvcc->encaps == e_llc)
 160                 memcpy(skb_push(skb, 8), llc_oui_pid_pad, 8);
 161         /* last 2 bytes of llc_oui_pid_pad are managed by header routines;
 162            yes, you got it: 8 + 2 = sizeof(llc_oui_pid_pad)
 163          */
 164 #else
 165         int minheadroom = (brvcc->encaps == e_llc) ? 10 : 2;
 166         if (skb_headroom(skb) < minheadroom) {
 167                 struct sk_buff *skb2 = skb_realloc_headroom(skb, minheadroom);
 168                 brvcc->copies_needed++;
 169                 dev_kfree_skb(skb);
 170                 if (skb2 == NULL) {
 171                         brvcc->copies_failed++;
 172                         return 0;
 173                 }
 174                 skb = skb2;
 175         }
 176         skb_push(skb, minheadroom);
 177         if (brvcc->encaps == e_llc)
 178                 memcpy(skb->data, llc_oui_pid_pad, 10);
 179         else
 180                 memset(skb->data, 0, 2);
 181 #endif /* FASTER_VERSION */
 182         skb_debug(skb);
 183
 184         ATM_SKB(skb)->vcc = atmvcc = brvcc->atmvcc;
 185         DPRINTK("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, atmvcc, atmvcc->dev);
 186         if (!atm_may_send(atmvcc, skb->truesize)) {
 187                 /* we free this here for now, because we cannot know in a higher
 188                         layer whether the skb point it supplied wasn't freed yet.
 189                         now, it always is.
 190                 */
 191                 dev_kfree_skb(skb);
 192                 return 0;
 193                 }
 194         atomic_add(skb->truesize, &atmvcc->sk->wmem_alloc);
 195         ATM_SKB(skb)->atm_options = atmvcc->atm_options;
 196         brdev->stats.tx_packets++;
 197         brdev->stats.tx_bytes += skb->len;
 198         atmvcc->send(atmvcc, skb);
 199         return 1;
 200 }
 201
 202 static inline struct br2684_vcc *pick_outgoing_vcc(struct sk_buff *skb,
 203         struct br2684_dev *brdev)
 204 {
 205         return list_empty(&brdev->brvccs) ? NULL :
 206             list_entry_brvcc(brdev->brvccs.next); /* 1 vcc/dev right now */
 207 }
 208
 209 static int br2684_start_xmit(struct sk_buff *skb, struct net_device *dev)
 210 {
 211         struct br2684_dev *brdev = BRPRIV(dev);
 212         struct br2684_vcc *brvcc;
 213
 214         DPRINTK("br2684_start_xmit, skb->dst=%p\n", skb->dst);
 215         read_lock(&devs_lock);
 216         brvcc = pick_outgoing_vcc(skb, brdev);
 217         if (brvcc == NULL) {
 218                 DPRINTK("no vcc attached to dev %s\n", dev->name);
 219                 brdev->stats.tx_errors++;
 220                 brdev->stats.tx_carrier_errors++;
 221                 /* netif_stop_queue(dev); */
 222                 dev_kfree_skb(skb);
 223                 read_unlock(&devs_lock);
 224                 return -EUNATCH;
 225         }
 226         if (!br2684_xmit_vcc(skb, brdev, brvcc)) {
 227                 /*
 228                  * We should probably use netif_*_queue() here, but that
 229                  * involves added complication.  We need to walk before
 230                  * we can run
 231                  */
 232                 /* don't free here! this pointer might be no longer valid!
 233                 dev_kfree_skb(skb);
 234                 */
 235                 brdev->stats.tx_errors++;
 236                 brdev->stats.tx_fifo_errors++;
 237         }
 238         read_unlock(&devs_lock);
 239         return 0;
 240 }
 241
 242 static struct net_device_stats *br2684_get_stats(struct net_device *dev)
 243 {
 244         DPRINTK("br2684_get_stats\n");
 245         return &BRPRIV(dev)->stats;
 246 }
 247
 248 #ifdef FASTER_VERSION
 249 /*
 250  * These mirror eth_header and eth_header_cache.  They are not usually
 251  * exported for use in modules, so we grab them from net_device
 252  * after ether_setup() is done with it.  Bit of a hack.
 253  */
 254 static int (*my_eth_header)(struct sk_buff *, struct net_device *,
 255         unsigned short, void *, void *, unsigned);
 256 static int (*my_eth_header_cache)(struct neighbour *, struct hh_cache *);
 257
 258 static int
 259 br2684_header(struct sk_buff *skb, struct net_device *dev,
 260               unsigned short type, void *daddr, void *saddr, unsigned len)
 261 {
 262         u16 *pad_before_eth;
 263         int t = my_eth_header(skb, dev, type, daddr, saddr, len);
 264         if (t > 0) {
 265                 pad_before_eth = (u16 *) skb_push(skb, 2);
 266                 *pad_before_eth = 0;
 267                 return dev->hard_header_len;    /* or return 16; ? */
 268         } else
 269                 return t;
 270 }
 271
 272 static int
 273 br2684_header_cache(struct neighbour *neigh, struct hh_cache *hh)
 274 {
 275 /* hh_data is 16 bytes long. if encaps is ether-llc we need 24, so
 276 xmit will add the additional header part in that case */
 277         u16 *pad_before_eth = (u16 *)(hh->hh_data);
 278         int t = my_eth_header_cache(neigh, hh);
 279         DPRINTK("br2684_header_cache, neigh=%p, hh_cache=%p\n", neigh, hh);
 280         if (t < 0)
 281                 return t;
 282         else {
 283                 *pad_before_eth = 0;
 284                 hh->hh_len = PADLEN + ETH_HLEN;
 285         }
 286         return 0;
 287 }
 288
 289 /*
 290  * This is similar to eth_type_trans, which cannot be used because of
 291  * our dev->hard_header_len
 292  */
 293 static inline unsigned short br_type_trans(struct sk_buff *skb,
 294                                                struct net_device *dev)
 295 {
 296         struct ethhdr *eth;
 297         unsigned char *rawp;
 298         eth = skb->mac.ethernet;
 299
 300         if (*eth->h_dest & 1) {
 301                 if (memcmp(eth->h_dest, dev->broadcast, ETH_ALEN) == 0)
 302                         skb->pkt_type = PACKET_BROADCAST;
 303                 else
 304                         skb->pkt_type = PACKET_MULTICAST;
 305         }
 306
 307         else if (memcmp(eth->h_dest, dev->dev_addr, ETH_ALEN))
 308                 skb->pkt_type = PACKET_OTHERHOST;
 309
 310         if (ntohs(eth->h_proto) >= 1536)
 311                 return eth->h_proto;
 312
 313         rawp = skb->data;
 314
 315         /*
 316          * This is a magic hack to spot IPX packets. Older Novell breaks
 317          * the protocol design and runs IPX over 802.3 without an 802.2 LLC
 318          * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
 319          * won't work for fault tolerant netware but does for the rest.
 320          */
 321         if (*(unsigned short *) rawp == 0xFFFF)
 322                 return htons(ETH_P_802_3);
 323
 324         /*
 325          * Real 802.2 LLC
 326          */
 327         return htons(ETH_P_802_2);
 328 }
 329 #endif /* FASTER_VERSION */
 330
 331 /*
 332  * We remember when the MAC gets set, so we don't override it later with
 333  * the ESI of the ATM card of the first VC
 334  */
 335 static int (*my_eth_mac_addr)(struct net_device *, void *);
 336 static int br2684_mac_addr(struct net_device *dev, void *p)
 337 {
 338         int err = my_eth_mac_addr(dev, p);
 339         if (!err)
 340                 BRPRIV(dev)->mac_was_set = 1;
 341         return err;
 342 }
 343
 344 #ifdef CONFIG_ATM_BR2684_IPFILTER
 345 /* this IOCTL is experimental. */
 346 static int br2684_setfilt(struct atm_vcc *atmvcc, unsigned long arg)
 347 {
 348         struct br2684_vcc *brvcc;
 349         struct br2684_filter_set fs;
 350
 351         if (copy_from_user(&fs, (void *) arg, sizeof fs))
 352                 return -EFAULT;
 353         if (fs.ifspec.method != BR2684_FIND_BYNOTHING) {
 354                 /*
 355                  * This is really a per-vcc thing, but we can also search
 356                  * by device
 357                  */
 358                 struct br2684_dev *brdev;
 359                 read_lock(&devs_lock);
 360                 brdev = br2684_find_dev(&fs.ifspec);
 361                 if (brdev == NULL || list_empty(&brdev->brvccs) ||
 362                     brdev->brvccs.next != brdev->brvccs.prev)  /* >1 VCC */
 363                         brvcc = NULL;
 364                 else
 365                         brvcc = list_entry_brvcc(brdev->brvccs.next);
 366                 read_unlock(&devs_lock);
 367                 if (brvcc == NULL)
 368                         return -ESRCH;
 369         } else
 370                 brvcc = BR2684_VCC(atmvcc);
 371         memcpy(&brvcc->filter, &fs.filter, sizeof(brvcc->filter));
 372         return 0;
 373 }
 374
 375 /* Returns 1 if packet should be dropped */
 376 static inline int
 377 packet_fails_filter(u16 type, struct br2684_vcc *brvcc, struct sk_buff *skb)
 378 {
 379         if (brvcc->filter.netmask == 0)
 380                 return 0;                       /* no filter in place */
 381         if (type == __constant_htons(ETH_P_IP) &&
 382             (((struct iphdr *) (skb->data))->daddr & brvcc->filter.
 383              netmask) == brvcc->filter.prefix)
 384                 return 0;
 385         if (type == __constant_htons(ETH_P_ARP))
 386                 return 0;
 387         /* TODO: we should probably filter ARPs too.. don't want to have
 388          *   them returning values that don't make sense, or is that ok?
 389          */
 390         return 1;               /* drop */
 391 }
 392 #endif /* CONFIG_ATM_BR2684_IPFILTER */
 393
 394 static void br2684_close_vcc(struct br2684_vcc *brvcc)
 395 {
 396         DPRINTK("removing VCC %p from dev %p\n", brvcc, brvcc->brdev);
 397         write_lock_irq(&devs_lock);
 398         list_del(&brvcc->brvccs);
 399         write_unlock_irq(&devs_lock);
 400         brvcc->atmvcc->user_back = NULL;        /* what about vcc->recvq ??? */
 401         brvcc->old_push(brvcc->atmvcc, NULL);   /* pass on the bad news */
 402         kfree(brvcc);
 403         MOD_DEC_USE_COUNT;
 404 }
 405
 406 /* when AAL5 PDU comes in: */
 407 static void br2684_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
 408 {
 409         struct br2684_vcc *brvcc = BR2684_VCC(atmvcc);
 410         struct br2684_dev *brdev = brvcc->brdev;
 411         int plen = sizeof(llc_oui_pid_pad) + ETH_HLEN;
 412
 413         DPRINTK("br2684_push\n");
 414
 415         if (skb == NULL) {      /* skb==NULL means VCC is being destroyed */
 416                 br2684_close_vcc(brvcc);
 417                 if (list_empty(&brdev->brvccs)) {
 418                         read_lock(&devs_lock);
 419                         list_del(&brdev->br2684_devs);
 420                         read_unlock(&devs_lock);
 421                         unregister_netdev(&brdev->net_dev);
 422                         kfree(brdev);
 423                 }
 424                 return;
 425         }
 426
 427         skb_debug(skb);
 428         atm_return(atmvcc, skb->truesize);
 429         DPRINTK("skb from brdev %p\n", brdev);
 430         if (brvcc->encaps == e_llc) {
 431                 /* let us waste some time for checking the encapsulation.
 432                    Note, that only 7 char is checked so frames with a valid FCS
 433                    are also accepted (but FCS is not checked of course) */
 434                 if (memcmp(skb->data, llc_oui_pid_pad, 7)) {
 435                         brdev->stats.rx_errors++;
 436                         dev_kfree_skb(skb);
 437                         return;
 438                 }
 439
 440                 /* Strip FCS if present */
 441                 if (skb->len > 7 && skb->data[7] == 0x01)
 442                         __skb_trim(skb, skb->len - 4);
 443         } else {
 444                 plen = PADLEN + ETH_HLEN;       /* pad, dstmac,srcmac, ethtype */
 445                 /* first 2 chars should be 0 */
 446                 if (*((u16 *) (skb->data)) != 0) {
 447                         brdev->stats.rx_errors++;
 448                         dev_kfree_skb(skb);
 449                         return;
 450                 }
 451         }
 452         if (skb->len < plen) {
 453                 brdev->stats.rx_errors++;
 454                 dev_kfree_skb(skb);     /* dev_ not needed? */
 455                 return;
 456         }
 457
 458 #ifdef FASTER_VERSION
 459         /* FIXME: tcpdump shows that pointer to mac header is 2 bytes earlier,
 460            than should be. What else should I set? */
 461         skb_pull(skb, plen);
 462         skb->mac.raw = ((char *) (skb->data)) - ETH_HLEN;
 463         skb->pkt_type = PACKET_HOST;
 464 #ifdef CONFIG_BR2684_FAST_TRANS
 465         skb->protocol = ((u16 *) skb->data)[-1];
 466 #else                           /* some protocols might require this: */
 467         skb->protocol = br_type_trans(skb, &brdev->net_dev);
 468 #endif /* CONFIG_BR2684_FAST_TRANS */
 469 #else
 470         skb_pull(skb, plen - ETH_HLEN);
 471         skb->protocol = eth_type_trans(skb, &brdev->net_dev);
 472 #endif /* FASTER_VERSION */
 473 #ifdef CONFIG_ATM_BR2684_IPFILTER
 474         if (packet_fails_filter(skb->protocol, brvcc, skb)) {
 475                 brdev->stats.rx_dropped++;
 476                 dev_kfree_skb(skb);
 477                 return;
 478         }
 479 #endif /* CONFIG_ATM_BR2684_IPFILTER */
 480         skb->dev = &brdev->net_dev;
 481         ATM_SKB(skb)->vcc = atmvcc;     /* needed ? */
 482         DPRINTK("received packet's protocol: %x\n", ntohs(skb->protocol));
 483         skb_debug(skb);
 484         if (!(brdev->net_dev.flags & IFF_UP)) { /* sigh, interface is down */
 485                 brdev->stats.rx_dropped++;
 486                 dev_kfree_skb(skb);
 487                 return;
 488         }
 489         brdev->stats.rx_packets++;
 490         brdev->stats.rx_bytes += skb->len;
 491         memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
 492         netif_rx(skb);
 493 }
 494
 495 static int br2684_regvcc(struct atm_vcc *atmvcc, unsigned long arg)
 496 {
 497 /* assign a vcc to a dev
 498 Note: we do not have explicit unassign, but look at _push()
 499 */
 500         int err;
 501         struct br2684_vcc *brvcc;
 502         struct sk_buff_head copy;
 503         struct sk_buff *skb;
 504         struct br2684_dev *brdev;
 505         struct atm_backend_br2684 be;
 506
 507         MOD_INC_USE_COUNT;
 508         if (copy_from_user(&be, (void *) arg, sizeof be)) {
 509                 MOD_DEC_USE_COUNT;
 510                 return -EFAULT;
 511         }
 512         write_lock_irq(&devs_lock);
 513         brdev = br2684_find_dev(&be.ifspec);
 514         if (brdev == NULL) {
 515                 printk(KERN_ERR
 516                     "br2684: tried to attach to non-existant device\n");
 517                 err = -ENXIO;
 518                 goto error;
 519         }
 520         if (atmvcc->push == NULL) {
 521                 err = -EBADFD;
 522                 goto error;
 523         }
 524         if (!list_empty(&brdev->brvccs)) {      /* Only 1 VCC/dev right now */
 525                 err = -EEXIST;
 526                 goto error;
 527         }
 528         if (be.fcs_in != BR2684_FCSIN_NO || be.fcs_out != BR2684_FCSOUT_NO ||
 529             be.fcs_auto || be.has_vpiid || be.send_padding || (be.encaps !=
 530             BR2684_ENCAPS_VC && be.encaps != BR2684_ENCAPS_LLC) ||
 531             be.min_size != 0) {
 532                 err = -EINVAL;
 533                 goto error;
 534         }
 535         brvcc = kmalloc(sizeof(struct br2684_vcc), GFP_KERNEL);
 536         if (!brvcc) {
 537                 err = -ENOMEM;
 538                 goto error;
 539         }
 540         memset(brvcc, 0, sizeof(struct br2684_vcc));
 541         DPRINTK("br2684_regvcc vcc=%p, encaps=%d, brvcc=%p\n", atmvcc, be.encaps,
 542                 brvcc);
 543         if (list_empty(&brdev->brvccs) && !brdev->mac_was_set) {
 544                 unsigned char *esi = atmvcc->dev->esi;
 545                 if (esi[0] | esi[1] | esi[2] | esi[3] | esi[4] | esi[5])
 546                         memcpy(brdev->net_dev.dev_addr, esi,
 547                             brdev->net_dev.addr_len);
 548                 else
 549                         brdev->net_dev.dev_addr[2] = 1;
 550         }
 551         list_add(&brvcc->brvccs, &brdev->brvccs);
 552         write_unlock_irq(&devs_lock);
 553         brvcc->brdev = brdev;
 554         brvcc->atmvcc = atmvcc;
 555         atmvcc->user_back = brvcc;
 556         brvcc->encaps = (enum br2684_encaps) be.encaps;
 557         brvcc->old_push = atmvcc->push;
 558         barrier();
 559         atmvcc->push = br2684_push;
 560         skb_queue_head_init(&copy);
 561         skb_migrate(&atmvcc->sk->receive_queue, &copy);
 562         while ((skb = skb_dequeue(&copy))) {
 563                 BRPRIV(skb->dev)->stats.rx_bytes -= skb->len;
 564                 BRPRIV(skb->dev)->stats.rx_packets--;
 565                 br2684_push(atmvcc, skb);
 566         }
 567         return 0;
 568     error:
 569         write_unlock_irq(&devs_lock);
 570         MOD_DEC_USE_COUNT;
 571         return err;
 572 }
 573
 574 static int br2684_create(unsigned long arg)
 575 {
 576         int err;
 577         struct br2684_dev *brdev;
 578         struct atm_newif_br2684 ni;
 579
 580         DPRINTK("br2684_create\n");
 581         /*
 582          * We track module use by vcc's NOT the devices they're on.  We're
 583          * protected here against module death by the kernel_lock, but if
 584          * we need to sleep we should make sure that the module doesn't
 585          * disappear under us.
 586          */
 587         MOD_INC_USE_COUNT;
 588         if (copy_from_user(&ni, (void *) arg, sizeof ni)) {
 589                 MOD_DEC_USE_COUNT;
 590                 return -EFAULT;
 591         }
 592         if (ni.media != BR2684_MEDIA_ETHERNET || ni.mtu != 1500) {
 593                 MOD_DEC_USE_COUNT;
 594                 return -EINVAL;
 595         }
 596         if ((brdev = kmalloc(sizeof(struct br2684_dev), GFP_KERNEL)) == NULL) {
 597                 MOD_DEC_USE_COUNT;
 598                 return -ENOMEM;
 599         }
 600         memset(brdev, 0, sizeof(struct br2684_dev));
 601         INIT_LIST_HEAD(&brdev->brvccs);
 602
 603         write_lock_irq(&devs_lock);
 604         brdev->number = list_empty(&br2684_devs) ? 1 :
 605             list_entry_brdev(br2684_devs.prev)->number + 1;
 606         list_add_tail(&brdev->br2684_devs, &br2684_devs);
 607         write_unlock_irq(&devs_lock);
 608
 609         if (ni.ifname[0] != '\0') {
 610                 memcpy(brdev->net_dev.name, ni.ifname,
 611                     sizeof(brdev->net_dev.name));
 612                 brdev->net_dev.name[sizeof(brdev->net_dev.name) - 1] = '\0';
 613         } else
 614                 sprintf(brdev->net_dev.name, "nas%d", brdev->number);
 615         DPRINTK("registered netdev %s\n", brdev->net_dev.name);
 616         ether_setup(&brdev->net_dev);
 617         brdev->mac_was_set = 0;
 618 #ifdef FASTER_VERSION
 619         my_eth_header = brdev->net_dev.hard_header;
 620         brdev->net_dev.hard_header = br2684_header;
 621         my_eth_header_cache = brdev->net_dev.hard_header_cache;
 622         brdev->net_dev.hard_header_cache = br2684_header_cache;
 623         brdev->net_dev.hard_header_len = sizeof(llc_oui_pid_pad) + ETH_HLEN;    /* 10 + 14 */
 624 #endif
 625         my_eth_mac_addr = brdev->net_dev.set_mac_address;
 626         brdev->net_dev.set_mac_address = br2684_mac_addr;
 627         brdev->net_dev.hard_start_xmit = br2684_start_xmit;
 628         brdev->net_dev.get_stats = br2684_get_stats;
 629
 630         /* open, stop, do_ioctl ? */
 631         err = register_netdev(&brdev->net_dev);
 632         MOD_DEC_USE_COUNT;
 633         if (err < 0) {
 634                 printk(KERN_ERR "br2684_create: register_netdev failed\n");
 635                 write_lock_irq(&devs_lock);
 636                 list_del(&brdev->br2684_devs);
 637                 write_unlock_irq(&devs_lock);
 638                 kfree(brdev);
 639                 return err;
 640         }
 641         return 0;
 642 }
 643
 644 /*
 645  * This handles ioctls actually performed on our vcc - we must return
 646  * -ENOIOCTLCMD for any unrecognized ioctl
 647  */
 648 static int br2684_ioctl(struct atm_vcc *atmvcc, unsigned int cmd,
 649         unsigned long arg)
 650 {
 651         int err;
 652         switch(cmd) {
 653         case ATM_SETBACKEND:
 654         case ATM_NEWBACKENDIF: {
 655                 atm_backend_t b;
 656                 MOD_INC_USE_COUNT;
 657                 err = get_user(b, (atm_backend_t *) arg);
 658                 MOD_DEC_USE_COUNT;
 659                 if (err)
 660                         return -EFAULT;
 661                 if (b != ATM_BACKEND_BR2684)
 662                         return -ENOIOCTLCMD;
 663                 if (!capable(CAP_NET_ADMIN))
 664                         return -EPERM;
 665                 if (cmd == ATM_SETBACKEND)
 666                         return br2684_regvcc(atmvcc, arg);
 667                 else
 668                         return br2684_create(arg);
 669                 }
 670 #ifdef CONFIG_ATM_BR2684_IPFILTER
 671         case BR2684_SETFILT:
 672                 if (atmvcc->push != br2684_push)
 673                         return -ENOIOCTLCMD;
 674                 if (!capable(CAP_NET_ADMIN))
 675                         return -EPERM;
 676                 MOD_INC_USE_COUNT;
 677                 err = br2684_setfilt(atmvcc, arg);
 678                 MOD_DEC_USE_COUNT;
 679                 return err;
 680 #endif /* CONFIG_ATM_BR2684_IPFILTER */
 681         }
 682         return -ENOIOCTLCMD;
 683 }
 684
 685 #ifdef CONFIG_PROC_FS
 686 /* Never put more than 256 bytes in at once */
 687 static int br2684_proc_engine(loff_t pos, char *buf)
 688 {
 689         struct list_head *lhd, *lhc;
 690         struct br2684_dev *brdev;
 691         struct br2684_vcc *brvcc;
 692         list_for_each(lhd, &br2684_devs) {
 693                 brdev = list_entry_brdev(lhd);
 694                 if (pos-- == 0)
 695                         return sprintf(buf, "dev %.16s: num=%d, mac=%02X:%02X:"
 696                             "%02X:%02X:%02X:%02X (%s)\n", brdev->net_dev.name,
 697                             brdev->number,
 698                             brdev->net_dev.dev_addr[0],
 699                             brdev->net_dev.dev_addr[1],
 700                             brdev->net_dev.dev_addr[2],
 701                             brdev->net_dev.dev_addr[3],
 702                             brdev->net_dev.dev_addr[4],
 703                             brdev->net_dev.dev_addr[5],
 704                             brdev->mac_was_set ? "set" : "auto");
 705                 list_for_each(lhc, &brdev->brvccs) {
 706                         brvcc = list_entry_brvcc(lhc);
 707                         if (pos-- == 0)
 708                                 return sprintf(buf, "  vcc %d.%d.%d: encaps=%s"
 709 #ifndef FASTER_VERSION
 710                                     ", failed copies %u/%u"
 711 #endif /* FASTER_VERSION */
 712                                     "\n", brvcc->atmvcc->dev->number,
 713                                     brvcc->atmvcc->vpi, brvcc->atmvcc->vci,
 714                                     (brvcc->encaps == e_llc) ? "LLC" : "VC"
 715 #ifndef FASTER_VERSION
 716                                     , brvcc->copies_failed
 717                                     , brvcc->copies_needed
 718 #endif /* FASTER_VERSION */
 719                                     );
 720 #ifdef CONFIG_ATM_BR2684_IPFILTER
 721 #define b1(var, byte)   ((u8 *) &brvcc->filter.var)[byte]
 722 #define bs(var)         b1(var, 0), b1(var, 1), b1(var, 2), b1(var, 3)
 723                         if (brvcc->filter.netmask != 0 && pos-- == 0)
 724                                 return sprintf(buf, "    filter=%d.%d.%d.%d/"
 725                                     "%d.%d.%d.%d\n", bs(prefix), bs(netmask));
 726 #undef bs
 727 #undef b1
 728 #endif /* CONFIG_ATM_BR2684_IPFILTER */
 729                 }
 730         }
 731         return 0;
 732 }
 733
 734 static ssize_t br2684_proc_read(struct file *file, char *buf, size_t count,
 735         loff_t *pos)
 736 {
 737         unsigned long page;
 738         int len = 0, x, left;
 739         loff_t n = *pos;
 740
 741         page = get_free_page(GFP_KERNEL);
 742         if (!page)
 743                 return -ENOMEM;
 744         left = PAGE_SIZE - 256;
 745         if (count < left)
 746                 left = count;
 747         read_lock(&devs_lock);
 748         for (;;) {
 749                 x = br2684_proc_engine(n, &((char *) page)[len]);
 750                 if (x == 0)
 751                         break;
 752                 if (x > left)
 753                         /*
 754                          * This should only happen if the user passed in
 755                          * a "count" too small for even one line
 756                          */
 757                         x = -EINVAL;
 758                 if (x < 0) {
 759                         len = x;
 760                         break;
 761                 }
 762                 len += x;
 763                 left -= x;
 764                 n++;
 765                 if (left < 256)
 766                         break;
 767         }
 768         read_unlock(&devs_lock);
 769         *pos = n;
 770         if (len > 0 && copy_to_user(buf, (char *) page, len))
 771                 len = -EFAULT;
 772         free_page(page);
 773         return len;
 774 }
 775
 776 static struct file_operations br2684_proc_operations = {
 777         read: br2684_proc_read,
 778 };
 779
 780 extern struct proc_dir_entry *atm_proc_root;    /* from proc.c */
 781 #endif /* CONFIG_PROC_FS */
 782
 783 /* the following avoids some spurious warnings from the compiler */
 784 #define UNUSED __attribute__((unused))
 785
 786 static int __init UNUSED br2684_init(void)
 787 {
 788 #ifdef CONFIG_PROC_FS
 789         struct proc_dir_entry *p;
 790         if ((p = create_proc_entry("br2684", 0, atm_proc_root)) == NULL)
 791                 return -ENOMEM;
 792         p->proc_fops = &br2684_proc_operations;
 793 #endif /* CONFIG_PROC_FS */
 794         br2684_ioctl_set(br2684_ioctl);
 795         return 0;
 796 }
 797
 798 static void __exit UNUSED br2684_exit(void)
 799 {
 800         struct br2684_dev *brdev;
 801         br2684_ioctl_set(NULL);
 802 #ifdef CONFIG_PROC_FS
 803         remove_proc_entry("br2684", atm_proc_root);
 804 #endif /* CONFIG_PROC_FS */
 805         while (!list_empty(&br2684_devs)) {
 806                 brdev = list_entry_brdev(br2684_devs.next);
 807                 unregister_netdev(&brdev->net_dev);
 808                 list_del(&brdev->br2684_devs);
 809                 kfree(brdev);
 810         }
 811 }
 812
 813 module_init(br2684_init);
 814 module_exit(br2684_exit);
 815
 816 MODULE_AUTHOR("Marcell GAL");
 817 MODULE_DESCRIPTION("RFC2684 bridged protocols over ATM/AAL5");
 818 MODULE_LICENSE("GPL");