drivers/net/pppoe.c

   1 /** -*- linux-c -*- ***********************************************************
   2  * Linux PPP over Ethernet (PPPoX/PPPoE) Sockets
   3  *
   4  * PPPoX --- Generic PPP encapsulation socket family
   5  * PPPoE --- PPP over Ethernet (RFC 2516)
   6  *
   7  *
   8  * Version:     0.7.0
   9  *
  10  * 070228 :     Fix to allow multiple sessions with same remote MAC and same
  11  *              session id by including the local device ifindex in the
  12  *              tuple identifying a session. This also ensures packets can't
  13  *              be injected into a session from interfaces other than the one
  14  *              specified by userspace. Florian Zumbiehl <florz@florz.de>
  15  *              (Oh, BTW, this one is YYMMDD, in case you were wondering ...)
  16  * 220102 :     Fix module use count on failure in pppoe_create, pppox_sk -acme
  17  * 030700 :     Fixed connect logic to allow for disconnect.
  18  * 270700 :     Fixed potential SMP problems; we must protect against
  19  *              simultaneous invocation of ppp_input
  20  *              and ppp_unregister_channel.
  21  * 040800 :     Respect reference count mechanisms on net-devices.
  22  * 200800 :     fix kfree(skb) in pppoe_rcv (acme)
  23  *              Module reference count is decremented in the right spot now,
  24  *              guards against sock_put not actually freeing the sk
  25  *              in pppoe_release.
  26  * 051000 :     Initialization cleanup.
  27  * 111100 :     Fix recvmsg.
  28  * 050101 :     Fix PADT procesing.
  29  * 140501 :     Use pppoe_rcv_core to handle all backlog. (Alexey)
  30  * 170701 :     Do not lock_sock with rwlock held. (DaveM)
  31  *              Ignore discovery frames if user has socket
  32  *              locked. (DaveM)
  33  *              Ignore return value of dev_queue_xmit in __pppoe_xmit
  34  *              or else we may kfree an SKB twice. (DaveM)
  35  * 190701 :     When doing copies of skb's in __pppoe_xmit, always delete
  36  *              the original skb that was passed in on success, never on
  37  *              failure.  Delete the copy of the skb on failure to avoid
  38  *              a memory leak.
  39  * 081001 :     Misc. cleanup (licence string, non-blocking, prevent
  40  *              reference of device on close).
  41  * 121301 :     New ppp channels interface; cannot unregister a channel
  42  *              from interrupts.  Thus, we mark the socket as a ZOMBIE
  43  *              and do the unregistration later.
  44  * 081002 :     seq_file support for proc stuff -acme
  45  * 111602 :     Merge all 2.4 fixes into 2.5/2.6 tree.  Label 2.5/2.6
  46  *              as version 0.7.  Spacing cleanup.
  47  * Author:      Michal Ostrowski <mostrows@speakeasy.net>
  48  * Contributors:
  49  *              Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  50  *              David S. Miller (davem@redhat.com)
  51  *
  52  * License:
  53  *              This program is free software; you can redistribute it and/or
  54  *              modify it under the terms of the GNU General Public License
  55  *              as published by the Free Software Foundation; either version
  56  *              2 of the License, or (at your option) any later version.
  57  *
  58  */
  59
  60 #include <linux/string.h>
  61 #include <linux/module.h>
  62 #include <linux/kernel.h>
  63 #include <linux/slab.h>
  64 #include <linux/errno.h>
  65 #include <linux/netdevice.h>
  66 #include <linux/net.h>
  67 #include <linux/inetdevice.h>
  68 #include <linux/etherdevice.h>
  69 #include <linux/skbuff.h>
  70 #include <linux/init.h>
  71 #include <linux/if_ether.h>
  72 #include <linux/if_pppox.h>
  73 #include <linux/ppp_channel.h>
  74 #include <linux/ppp_defs.h>
  75 #include <linux/if_ppp.h>
  76 #include <linux/notifier.h>
  77 #include <linux/file.h>
  78 #include <linux/proc_fs.h>
  79 #include <linux/seq_file.h>
  80
  81 #include <net/sock.h>
  82
  83 #include <asm/uaccess.h>
  84
  85 #define PPPOE_HASH_BITS 4
  86 #define PPPOE_HASH_SIZE (1<<PPPOE_HASH_BITS)
  87
  88 static struct ppp_channel_ops pppoe_chan_ops;
  89
  90 static int pppoe_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
  91 static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb);
  92 static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);
  93
  94 static const struct proto_ops pppoe_ops;
  95 static DEFINE_RWLOCK(pppoe_hash_lock);
  96
  97 static struct ppp_channel_ops pppoe_chan_ops;
  98
  99 static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
 100 {
 101         return (a->sid == b->sid &&
 102                 (memcmp(a->remote, b->remote, ETH_ALEN) == 0));
 103 }
 104
 105 static inline int cmp_addr(struct pppoe_addr *a, unsigned long sid, char *addr)
 106 {
 107         return (a->sid == sid &&
 108                 (memcmp(a->remote,addr,ETH_ALEN) == 0));
 109 }
 110
 111 static int hash_item(unsigned long sid, unsigned char *addr)
 112 {
 113         char hash = 0;
 114         int i, j;
 115
 116         for (i = 0; i < ETH_ALEN ; ++i) {
 117                 for (j = 0; j < 8/PPPOE_HASH_BITS ; ++j) {
 118                         hash ^= addr[i] >> ( j * PPPOE_HASH_BITS );
 119                 }
 120         }
 121
 122         for (i = 0; i < (sizeof(unsigned long)*8) / PPPOE_HASH_BITS ; ++i)
 123                 hash ^= sid >> (i*PPPOE_HASH_BITS);
 124
 125         return hash & ( PPPOE_HASH_SIZE - 1 );
 126 }
 127
 128 /* zeroed because its in .bss */
 129 static struct pppox_sock *item_hash_table[PPPOE_HASH_SIZE];
 130
 131 /**********************************************************************
 132  *
 133  *  Set/get/delete/rehash items  (internal versions)
 134  *
 135  **********************************************************************/
 136 static struct pppox_sock *__get_item(unsigned long sid, unsigned char *addr, int ifindex)
 137 {
 138         int hash = hash_item(sid, addr);
 139         struct pppox_sock *ret;
 140
 141         ret = item_hash_table[hash];
 142
 143         while (ret && !(cmp_addr(&ret->pppoe_pa, sid, addr) && ret->pppoe_ifindex == ifindex))
 144                 ret = ret->next;
 145
 146         return ret;
 147 }
 148
 149 static int __set_item(struct pppox_sock *po)
 150 {
 151         int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
 152         struct pppox_sock *ret;
 153
 154         ret = item_hash_table[hash];
 155         while (ret) {
 156                 if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) && ret->pppoe_ifindex == po->pppoe_ifindex)
 157                         return -EALREADY;
 158
 159                 ret = ret->next;
 160         }
 161
 162         po->next = item_hash_table[hash];
 163         item_hash_table[hash] = po;
 164
 165         return 0;
 166 }
 167
 168 static struct pppox_sock *__delete_item(unsigned long sid, char *addr, int ifindex)
 169 {
 170         int hash = hash_item(sid, addr);
 171         struct pppox_sock *ret, **src;
 172
 173         ret = item_hash_table[hash];
 174         src = &item_hash_table[hash];
 175
 176         while (ret) {
 177                 if (cmp_addr(&ret->pppoe_pa, sid, addr) && ret->pppoe_ifindex == ifindex) {
 178                         *src = ret->next;
 179                         break;
 180                 }
 181
 182                 src = &ret->next;
 183                 ret = ret->next;
 184         }
 185
 186         return ret;
 187 }
 188
 189 /**********************************************************************
 190  *
 191  *  Set/get/delete/rehash items
 192  *
 193  **********************************************************************/
 194 static inline struct pppox_sock *get_item(unsigned long sid,
 195                                          unsigned char *addr, int ifindex)
 196 {
 197         struct pppox_sock *po;
 198
 199         read_lock_bh(&pppoe_hash_lock);
 200         po = __get_item(sid, addr, ifindex);
 201         if (po)
 202                 sock_hold(sk_pppox(po));
 203         read_unlock_bh(&pppoe_hash_lock);
 204
 205         return po;
 206 }
 207
 208 static inline struct pppox_sock *get_item_by_addr(struct sockaddr_pppox *sp)
 209 {
 210         struct net_device *dev;
 211         int ifindex;
 212
 213         dev = dev_get_by_name(sp->sa_addr.pppoe.dev);
 214         if(!dev)
 215                 return NULL;
 216         ifindex = dev->ifindex;
 217         dev_put(dev);
 218         return get_item(sp->sa_addr.pppoe.sid, sp->sa_addr.pppoe.remote, ifindex);
 219 }
 220
 221 static inline struct pppox_sock *delete_item(unsigned long sid, char *addr, int ifindex)
 222 {
 223         struct pppox_sock *ret;
 224
 225         write_lock_bh(&pppoe_hash_lock);
 226         ret = __delete_item(sid, addr, ifindex);
 227         write_unlock_bh(&pppoe_hash_lock);
 228
 229         return ret;
 230 }
 231
 232
 233
 234 /***************************************************************************
 235  *
 236  *  Handler for device events.
 237  *  Certain device events require that sockets be unconnected.
 238  *
 239  **************************************************************************/
 240
 241 static void pppoe_flush_dev(struct net_device *dev)
 242 {
 243         int hash;
 244         BUG_ON(dev == NULL);
 245
 246         write_lock_bh(&pppoe_hash_lock);
 247         for (hash = 0; hash < PPPOE_HASH_SIZE; hash++) {
 248                 struct pppox_sock *po = item_hash_table[hash];
 249
 250                 while (po != NULL) {
 251                         struct sock *sk = sk_pppox(po);
 252                         if (po->pppoe_dev != dev) {
 253                                 po = po->next;
 254                                 continue;
 255                         }
 256                         po->pppoe_dev = NULL;
 257                         dev_put(dev);
 258
 259
 260                         /* We always grab the socket lock, followed by the
 261                          * pppoe_hash_lock, in that order.  Since we should
 262                          * hold the sock lock while doing any unbinding,
 263                          * we need to release the lock we're holding.
 264                          * Hold a reference to the sock so it doesn't disappear
 265                          * as we're jumping between locks.
 266                          */
 267
 268                         sock_hold(sk);
 269
 270                         write_unlock_bh(&pppoe_hash_lock);
 271                         lock_sock(sk);
 272
 273                         if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
 274                                 pppox_unbind_sock(sk);
 275                                 sk->sk_state = PPPOX_ZOMBIE;
 276                                 sk->sk_state_change(sk);
 277                         }
 278
 279                         release_sock(sk);
 280                         sock_put(sk);
 281
 282                         /* Restart scan at the beginning of this hash chain.
 283                          * While the lock was dropped the chain contents may
 284                          * have changed.
 285                          */
 286                         write_lock_bh(&pppoe_hash_lock);
 287                         po = item_hash_table[hash];
 288                 }
 289         }
 290         write_unlock_bh(&pppoe_hash_lock);
 291 }
 292
 293 static int pppoe_device_event(struct notifier_block *this,
 294                               unsigned long event, void *ptr)
 295 {
 296         struct net_device *dev = (struct net_device *) ptr;
 297
 298         /* Only look at sockets that are using this specific device. */
 299         switch (event) {
 300         case NETDEV_CHANGEMTU:
 301                 /* A change in mtu is a bad thing, requiring
 302                  * LCP re-negotiation.
 303                  */
 304
 305         case NETDEV_GOING_DOWN:
 306         case NETDEV_DOWN:
 307                 /* Find every socket on this device and kill it. */
 308                 pppoe_flush_dev(dev);
 309                 break;
 310
 311         default:
 312                 break;
 313         };
 314
 315         return NOTIFY_DONE;
 316 }
 317
 318
 319 static struct notifier_block pppoe_notifier = {
 320         .notifier_call = pppoe_device_event,
 321 };
 322
 323
 324 /************************************************************************
 325  *
 326  * Do the real work of receiving a PPPoE Session frame.
 327  *
 328  ***********************************************************************/
 329 static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
 330 {
 331         struct pppox_sock *po = pppox_sk(sk);
 332         struct pppox_sock *relay_po;
 333
 334         if (sk->sk_state & PPPOX_BOUND) {
 335                 struct pppoe_hdr *ph = pppoe_hdr(skb);
 336                 int len = ntohs(ph->length);
 337                 skb_pull_rcsum(skb, sizeof(struct pppoe_hdr));
 338                 if (pskb_trim_rcsum(skb, len))
 339                         goto abort_kfree;
 340
 341                 ppp_input(&po->chan, skb);
 342         } else if (sk->sk_state & PPPOX_RELAY) {
 343                 relay_po = get_item_by_addr(&po->pppoe_relay);
 344
 345                 if (relay_po == NULL)
 346                         goto abort_kfree;
 347
 348                 if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
 349                         goto abort_put;
 350
 351                 skb_pull(skb, sizeof(struct pppoe_hdr));
 352                 if (!__pppoe_xmit(sk_pppox(relay_po), skb))
 353                         goto abort_put;
 354         } else {
 355                 if (sock_queue_rcv_skb(sk, skb))
 356                         goto abort_kfree;
 357         }
 358
 359         return NET_RX_SUCCESS;
 360
 361 abort_put:
 362         sock_put(sk_pppox(relay_po));
 363
 364 abort_kfree:
 365         kfree_skb(skb);
 366         return NET_RX_DROP;
 367 }
 368
 369 /************************************************************************
 370  *
 371  * Receive wrapper called in BH context.
 372  *
 373  ***********************************************************************/
 374 static int pppoe_rcv(struct sk_buff *skb,
 375                      struct net_device *dev,
 376                      struct packet_type *pt,
 377                      struct net_device *orig_dev)
 378
 379 {
 380         struct pppoe_hdr *ph;
 381         struct pppox_sock *po;
 382
 383         if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
 384                 goto drop;
 385
 386         if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
 387                 goto out;
 388
 389         ph = pppoe_hdr(skb);
 390
 391         po = get_item((unsigned long) ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
 392         if (po != NULL)
 393                 return sk_receive_skb(sk_pppox(po), skb, 0);
 394 drop:
 395         kfree_skb(skb);
 396 out:
 397         return NET_RX_DROP;
 398 }
 399
 400 /************************************************************************
 401  *
 402  * Receive a PPPoE Discovery frame.
 403  * This is solely for detection of PADT frames
 404  *
 405  ***********************************************************************/
 406 static int pppoe_disc_rcv(struct sk_buff *skb,
 407                           struct net_device *dev,
 408                           struct packet_type *pt,
 409                           struct net_device *orig_dev)
 410
 411 {
 412         struct pppoe_hdr *ph;
 413         struct pppox_sock *po;
 414
 415         if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
 416                 goto abort;
 417
 418         if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
 419                 goto out;
 420
 421         ph = pppoe_hdr(skb);
 422         if (ph->code != PADT_CODE)
 423                 goto abort;
 424
 425         po = get_item((unsigned long) ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
 426         if (po) {
 427                 struct sock *sk = sk_pppox(po);
 428
 429                 bh_lock_sock(sk);
 430
 431                 /* If the user has locked the socket, just ignore
 432                  * the packet.  With the way two rcv protocols hook into
 433                  * one socket family type, we cannot (easily) distinguish
 434                  * what kind of SKB it is during backlog rcv.
 435                  */
 436                 if (sock_owned_by_user(sk) == 0) {
 437                         /* We're no longer connect at the PPPOE layer,
 438                          * and must wait for ppp channel to disconnect us.
 439                          */
 440                         sk->sk_state = PPPOX_ZOMBIE;
 441                 }
 442
 443                 bh_unlock_sock(sk);
 444                 sock_put(sk);
 445         }
 446
 447 abort:
 448         kfree_skb(skb);
 449 out:
 450         return NET_RX_SUCCESS; /* Lies... :-) */
 451 }
 452
 453 static struct packet_type pppoes_ptype = {
 454         .type   = __constant_htons(ETH_P_PPP_SES),
 455         .func   = pppoe_rcv,
 456 };
 457
 458 static struct packet_type pppoed_ptype = {
 459         .type   = __constant_htons(ETH_P_PPP_DISC),
 460         .func   = pppoe_disc_rcv,
 461 };
 462
 463 static struct proto pppoe_sk_proto = {
 464         .name     = "PPPOE",
 465         .owner    = THIS_MODULE,
 466         .obj_size = sizeof(struct pppox_sock),
 467 };
 468
 469 /***********************************************************************
 470  *
 471  * Initialize a new struct sock.
 472  *
 473  **********************************************************************/
 474 static int pppoe_create(struct socket *sock)
 475 {
 476         int error = -ENOMEM;
 477         struct sock *sk;
 478
 479         sk = sk_alloc(PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto, 1);
 480         if (!sk)
 481                 goto out;
 482
 483         sock_init_data(sock, sk);
 484
 485         sock->state = SS_UNCONNECTED;
 486         sock->ops   = &pppoe_ops;
 487
 488         sk->sk_backlog_rcv = pppoe_rcv_core;
 489         sk->sk_state       = PPPOX_NONE;
 490         sk->sk_type        = SOCK_STREAM;
 491         sk->sk_family      = PF_PPPOX;
 492         sk->sk_protocol    = PX_PROTO_OE;
 493
 494         error = 0;
 495 out:    return error;
 496 }
 497
 498 static int pppoe_release(struct socket *sock)
 499 {
 500         struct sock *sk = sock->sk;
 501         struct pppox_sock *po;
 502
 503         if (!sk)
 504                 return 0;
 505
 506         lock_sock(sk);
 507         if (sock_flag(sk, SOCK_DEAD)){
 508                 release_sock(sk);
 509                 return -EBADF;
 510         }
 511
 512         pppox_unbind_sock(sk);
 513
 514         /* Signal the death of the socket. */
 515         sk->sk_state = PPPOX_DEAD;
 516
 517
 518         /* Write lock on hash lock protects the entire "po" struct from
 519          * concurrent updates via pppoe_flush_dev. The "po" struct should
 520          * be considered part of the hash table contents, thus protected
 521          * by the hash table lock */
 522         write_lock_bh(&pppoe_hash_lock);
 523
 524         po = pppox_sk(sk);
 525         if (po->pppoe_pa.sid) {
 526                 __delete_item(po->pppoe_pa.sid,
 527                               po->pppoe_pa.remote, po->pppoe_ifindex);
 528         }
 529
 530         if (po->pppoe_dev) {
 531                 dev_put(po->pppoe_dev);
 532                 po->pppoe_dev = NULL;
 533         }
 534
 535         write_unlock_bh(&pppoe_hash_lock);
 536
 537         sock_orphan(sk);
 538         sock->sk = NULL;
 539
 540         skb_queue_purge(&sk->sk_receive_queue);
 541         release_sock(sk);
 542         sock_put(sk);
 543
 544         return 0;
 545 }
 546
 547
 548 static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
 549                   int sockaddr_len, int flags)
 550 {
 551         struct sock *sk = sock->sk;
 552         struct net_device *dev;
 553         struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
 554         struct pppox_sock *po = pppox_sk(sk);
 555         int error;
 556
 557         lock_sock(sk);
 558
 559         error = -EINVAL;
 560         if (sp->sa_protocol != PX_PROTO_OE)
 561                 goto end;
 562
 563         /* Check for already bound sockets */
 564         error = -EBUSY;
 565         if ((sk->sk_state & PPPOX_CONNECTED) && sp->sa_addr.pppoe.sid)
 566                 goto end;
 567
 568         /* Check for already disconnected sockets, on attempts to disconnect */
 569         error = -EALREADY;
 570         if ((sk->sk_state & PPPOX_DEAD) && !sp->sa_addr.pppoe.sid )
 571                 goto end;
 572
 573         error = 0;
 574         if (po->pppoe_pa.sid) {
 575                 pppox_unbind_sock(sk);
 576
 577                 /* Delete the old binding */
 578                 delete_item(po->pppoe_pa.sid,po->pppoe_pa.remote,po->pppoe_ifindex);
 579
 580                 if(po->pppoe_dev)
 581                         dev_put(po->pppoe_dev);
 582
 583                 memset(sk_pppox(po) + 1, 0,
 584                        sizeof(struct pppox_sock) - sizeof(struct sock));
 585
 586                 sk->sk_state = PPPOX_NONE;
 587         }
 588
 589         /* Don't re-bind if sid==0 */
 590         if (sp->sa_addr.pppoe.sid != 0) {
 591                 dev = dev_get_by_name(sp->sa_addr.pppoe.dev);
 592
 593                 error = -ENODEV;
 594                 if (!dev)
 595                         goto end;
 596
 597                 po->pppoe_dev = dev;
 598                 po->pppoe_ifindex = dev->ifindex;
 599
 600                 write_lock_bh(&pppoe_hash_lock);
 601                 if (!(dev->flags & IFF_UP)){
 602                         write_unlock_bh(&pppoe_hash_lock);
 603                         goto err_put;
 604                 }
 605
 606                 memcpy(&po->pppoe_pa,
 607                        &sp->sa_addr.pppoe,
 608                        sizeof(struct pppoe_addr));
 609
 610                 error = __set_item(po);
 611                 write_unlock_bh(&pppoe_hash_lock);
 612                 if (error < 0)
 613                         goto err_put;
 614
 615                 po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
 616                                    dev->hard_header_len);
 617
 618                 po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr);
 619                 po->chan.private = sk;
 620                 po->chan.ops = &pppoe_chan_ops;
 621
 622                 error = ppp_register_channel(&po->chan);
 623                 if (error)
 624                         goto err_put;
 625
 626                 sk->sk_state = PPPOX_CONNECTED;
 627         }
 628
 629         po->num = sp->sa_addr.pppoe.sid;
 630
 631  end:
 632         release_sock(sk);
 633         return error;
 634 err_put:
 635         if (po->pppoe_dev) {
 636                 dev_put(po->pppoe_dev);
 637                 po->pppoe_dev = NULL;
 638         }
 639         goto end;
 640 }
 641
 642
 643 static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
 644                   int *usockaddr_len, int peer)
 645 {
 646         int len = sizeof(struct sockaddr_pppox);
 647         struct sockaddr_pppox sp;
 648
 649         sp.sa_family    = AF_PPPOX;
 650         sp.sa_protocol  = PX_PROTO_OE;
 651         memcpy(&sp.sa_addr.pppoe, &pppox_sk(sock->sk)->pppoe_pa,
 652                sizeof(struct pppoe_addr));
 653
 654         memcpy(uaddr, &sp, len);
 655
 656         *usockaddr_len = len;
 657
 658         return 0;
 659 }
 660
 661
 662 static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
 663                 unsigned long arg)
 664 {
 665         struct sock *sk = sock->sk;
 666         struct pppox_sock *po = pppox_sk(sk);
 667         int val = 0;
 668         int err = 0;
 669
 670         switch (cmd) {
 671         case PPPIOCGMRU:
 672                 err = -ENXIO;
 673
 674                 if (!(sk->sk_state & PPPOX_CONNECTED))
 675                         break;
 676
 677                 err = -EFAULT;
 678                 if (put_user(po->pppoe_dev->mtu -
 679                              sizeof(struct pppoe_hdr) -
 680                              PPP_HDRLEN,
 681                              (int __user *) arg))
 682                         break;
 683                 err = 0;
 684                 break;
 685
 686         case PPPIOCSMRU:
 687                 err = -ENXIO;
 688                 if (!(sk->sk_state & PPPOX_CONNECTED))
 689                         break;
 690
 691                 err = -EFAULT;
 692                 if (get_user(val,(int __user *) arg))
 693                         break;
 694
 695                 if (val < (po->pppoe_dev->mtu
 696                            - sizeof(struct pppoe_hdr)
 697                            - PPP_HDRLEN))
 698                         err = 0;
 699                 else
 700                         err = -EINVAL;
 701                 break;
 702
 703         case PPPIOCSFLAGS:
 704                 err = -EFAULT;
 705                 if (get_user(val, (int __user *) arg))
 706                         break;
 707                 err = 0;
 708                 break;
 709
 710         case PPPOEIOCSFWD:
 711         {
 712                 struct pppox_sock *relay_po;
 713
 714                 err = -EBUSY;
 715                 if (sk->sk_state & (PPPOX_BOUND | PPPOX_ZOMBIE | PPPOX_DEAD))
 716                         break;
 717
 718                 err = -ENOTCONN;
 719                 if (!(sk->sk_state & PPPOX_CONNECTED))
 720                         break;
 721
 722                 /* PPPoE address from the user specifies an outbound
 723                    PPPoE address which frames are forwarded to */
 724                 err = -EFAULT;
 725                 if (copy_from_user(&po->pppoe_relay,
 726                                    (void __user *)arg,
 727                                    sizeof(struct sockaddr_pppox)))
 728                         break;
 729
 730                 err = -EINVAL;
 731                 if (po->pppoe_relay.sa_family != AF_PPPOX ||
 732                     po->pppoe_relay.sa_protocol!= PX_PROTO_OE)
 733                         break;
 734
 735                 /* Check that the socket referenced by the address
 736                    actually exists. */
 737                 relay_po = get_item_by_addr(&po->pppoe_relay);
 738
 739                 if (!relay_po)
 740                         break;
 741
 742                 sock_put(sk_pppox(relay_po));
 743                 sk->sk_state |= PPPOX_RELAY;
 744                 err = 0;
 745                 break;
 746         }
 747
 748         case PPPOEIOCDFWD:
 749                 err = -EALREADY;
 750                 if (!(sk->sk_state & PPPOX_RELAY))
 751                         break;
 752
 753                 sk->sk_state &= ~PPPOX_RELAY;
 754                 err = 0;
 755                 break;
 756
 757         default:;
 758         };
 759
 760         return err;
 761 }
 762
 763
 764 static int pppoe_sendmsg(struct kiocb *iocb, struct socket *sock,
 765                   struct msghdr *m, size_t total_len)
 766 {
 767         struct sk_buff *skb;
 768         struct sock *sk = sock->sk;
 769         struct pppox_sock *po = pppox_sk(sk);
 770         int error;
 771         struct pppoe_hdr hdr;
 772         struct pppoe_hdr *ph;
 773         struct net_device *dev;
 774         char *start;
 775
 776         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) {
 777                 error = -ENOTCONN;
 778                 goto end;
 779         }
 780
 781         hdr.ver = 1;
 782         hdr.type = 1;
 783         hdr.code = 0;
 784         hdr.sid = po->num;
 785
 786         lock_sock(sk);
 787
 788         dev = po->pppoe_dev;
 789
 790         error = -EMSGSIZE;
 791         if (total_len > (dev->mtu + dev->hard_header_len))
 792                 goto end;
 793
 794
 795         skb = sock_wmalloc(sk, total_len + dev->hard_header_len + 32,
 796                            0, GFP_KERNEL);
 797         if (!skb) {
 798                 error = -ENOMEM;
 799                 goto end;
 800         }
 801
 802         /* Reserve space for headers. */
 803         skb_reserve(skb, dev->hard_header_len);
 804         skb_reset_network_header(skb);
 805
 806         skb->dev = dev;
 807
 808         skb->priority = sk->sk_priority;
 809         skb->protocol = __constant_htons(ETH_P_PPP_SES);
 810
 811         ph = (struct pppoe_hdr *) skb_put(skb, total_len + sizeof(struct pppoe_hdr));
 812         start = (char *) &ph->tag[0];
 813
 814         error = memcpy_fromiovec(start, m->msg_iov, total_len);
 815
 816         if (error < 0) {
 817                 kfree_skb(skb);
 818                 goto end;
 819         }
 820
 821         error = total_len;
 822         dev->hard_header(skb, dev, ETH_P_PPP_SES,
 823                          po->pppoe_pa.remote, NULL, total_len);
 824
 825         memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
 826
 827         ph->length = htons(total_len);
 828
 829         dev_queue_xmit(skb);
 830
 831 end:
 832         release_sock(sk);
 833         return error;
 834 }
 835
 836
 837 /************************************************************************
 838  *
 839  * xmit function for internal use.
 840  *
 841  ***********************************************************************/
 842 static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
 843 {
 844         struct pppox_sock *po = pppox_sk(sk);
 845         struct net_device *dev = po->pppoe_dev;
 846         struct pppoe_hdr hdr;
 847         struct pppoe_hdr *ph;
 848         int headroom = skb_headroom(skb);
 849         int data_len = skb->len;
 850         struct sk_buff *skb2;
 851
 852         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 853                 goto abort;
 854
 855         hdr.ver = 1;
 856         hdr.type = 1;
 857         hdr.code = 0;
 858         hdr.sid = po->num;
 859         hdr.length = htons(skb->len);
 860
 861         if (!dev)
 862                 goto abort;
 863
 864         /* Copy the skb if there is no space for the header. */
 865         if (headroom < (sizeof(struct pppoe_hdr) + dev->hard_header_len)) {
 866                 skb2 = dev_alloc_skb(32+skb->len +
 867                                      sizeof(struct pppoe_hdr) +
 868                                      dev->hard_header_len);
 869
 870                 if (skb2 == NULL)
 871                         goto abort;
 872
 873                 skb_reserve(skb2, dev->hard_header_len + sizeof(struct pppoe_hdr));
 874                 skb_copy_from_linear_data(skb, skb_put(skb2, skb->len),
 875                                           skb->len);
 876         } else {
 877                 /* Make a clone so as to not disturb the original skb,
 878                  * give dev_queue_xmit something it can free.
 879                  */
 880                 skb2 = skb_clone(skb, GFP_ATOMIC);
 881
 882                 if (skb2 == NULL)
 883                         goto abort;
 884         }
 885
 886         ph = (struct pppoe_hdr *) skb_push(skb2, sizeof(struct pppoe_hdr));
 887         memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
 888         skb2->protocol = __constant_htons(ETH_P_PPP_SES);
 889
 890         skb_reset_network_header(skb2);
 891
 892         skb2->dev = dev;
 893
 894         dev->hard_header(skb2, dev, ETH_P_PPP_SES,
 895                          po->pppoe_pa.remote, NULL, data_len);
 896
 897         /* We're transmitting skb2, and assuming that dev_queue_xmit
 898          * will free it.  The generic ppp layer however, is expecting
 899          * that we give back 'skb' (not 'skb2') in case of failure,
 900          * but free it in case of success.
 901          */
 902
 903         if (dev_queue_xmit(skb2) < 0)
 904                 goto abort;
 905
 906         kfree_skb(skb);
 907         return 1;
 908
 909 abort:
 910         return 0;
 911 }
 912
 913
 914 /************************************************************************
 915  *
 916  * xmit function called by generic PPP driver
 917  * sends PPP frame over PPPoE socket
 918  *
 919  ***********************************************************************/
 920 static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 921 {
 922         struct sock *sk = (struct sock *) chan->private;
 923         return __pppoe_xmit(sk, skb);
 924 }
 925
 926
 927 static struct ppp_channel_ops pppoe_chan_ops = {
 928         .start_xmit = pppoe_xmit,
 929 };
 930
 931 static int pppoe_recvmsg(struct kiocb *iocb, struct socket *sock,
 932                   struct msghdr *m, size_t total_len, int flags)
 933 {
 934         struct sock *sk = sock->sk;
 935         struct sk_buff *skb;
 936         int error = 0;
 937
 938         if (sk->sk_state & PPPOX_BOUND) {
 939                 error = -EIO;
 940                 goto end;
 941         }
 942
 943         skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 944                                 flags & MSG_DONTWAIT, &error);
 945
 946         if (error < 0)
 947                 goto end;
 948
 949         m->msg_namelen = 0;
 950
 951         if (skb) {
 952                 struct pppoe_hdr *ph = pppoe_hdr(skb);
 953                 const int len = ntohs(ph->length);
 954
 955                 error = memcpy_toiovec(m->msg_iov, (unsigned char *) &ph->tag[0], len);
 956                 if (error == 0)
 957                         error = len;
 958         }
 959
 960         kfree_skb(skb);
 961 end:
 962         return error;
 963 }
 964
 965 #ifdef CONFIG_PROC_FS
 966 static int pppoe_seq_show(struct seq_file *seq, void *v)
 967 {
 968         struct pppox_sock *po;
 969         char *dev_name;
 970
 971         if (v == SEQ_START_TOKEN) {
 972                 seq_puts(seq, "Id       Address              Device\n");
 973                 goto out;
 974         }
 975
 976         po = v;
 977         dev_name = po->pppoe_pa.dev;
 978
 979         seq_printf(seq, "%08X %02X:%02X:%02X:%02X:%02X:%02X %8s\n",
 980                    po->pppoe_pa.sid,
 981                    po->pppoe_pa.remote[0], po->pppoe_pa.remote[1],
 982                    po->pppoe_pa.remote[2], po->pppoe_pa.remote[3],
 983                    po->pppoe_pa.remote[4], po->pppoe_pa.remote[5], dev_name);
 984 out:
 985         return 0;
 986 }
 987
 988 static __inline__ struct pppox_sock *pppoe_get_idx(loff_t pos)
 989 {
 990         struct pppox_sock *po;
 991         int i = 0;
 992
 993         for (; i < PPPOE_HASH_SIZE; i++) {
 994                 po = item_hash_table[i];
 995                 while (po) {
 996                         if (!pos--)
 997                                 goto out;
 998                         po = po->next;
 999                 }
1000         }
1001 out:
1002         return po;
1003 }
1004
1005 static void *pppoe_seq_start(struct seq_file *seq, loff_t *pos)
1006 {
1007         loff_t l = *pos;
1008
1009         read_lock_bh(&pppoe_hash_lock);
1010         return l ? pppoe_get_idx(--l) : SEQ_START_TOKEN;
1011 }
1012
1013 static void *pppoe_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1014 {
1015         struct pppox_sock *po;
1016
1017         ++*pos;
1018         if (v == SEQ_START_TOKEN) {
1019                 po = pppoe_get_idx(0);
1020                 goto out;
1021         }
1022         po = v;
1023         if (po->next)
1024                 po = po->next;
1025         else {
1026                 int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
1027
1028                 while (++hash < PPPOE_HASH_SIZE) {
1029                         po = item_hash_table[hash];
1030                         if (po)
1031                                 break;
1032                 }
1033         }
1034 out:
1035         return po;
1036 }
1037
1038 static void pppoe_seq_stop(struct seq_file *seq, void *v)
1039 {
1040         read_unlock_bh(&pppoe_hash_lock);
1041 }
1042
1043 static struct seq_operations pppoe_seq_ops = {
1044         .start          = pppoe_seq_start,
1045         .next           = pppoe_seq_next,
1046         .stop           = pppoe_seq_stop,
1047         .show           = pppoe_seq_show,
1048 };
1049
1050 static int pppoe_seq_open(struct inode *inode, struct file *file)
1051 {
1052         return seq_open(file, &pppoe_seq_ops);
1053 }
1054
1055 static const struct file_operations pppoe_seq_fops = {
1056         .owner          = THIS_MODULE,
1057         .open           = pppoe_seq_open,
1058         .read           = seq_read,
1059         .llseek         = seq_lseek,
1060         .release        = seq_release,
1061 };
1062
1063 static int __init pppoe_proc_init(void)
1064 {
1065         struct proc_dir_entry *p;
1066
1067         p = create_proc_entry("net/pppoe", S_IRUGO, NULL);
1068         if (!p)
1069                 return -ENOMEM;
1070
1071         p->proc_fops = &pppoe_seq_fops;
1072         return 0;
1073 }
1074 #else /* CONFIG_PROC_FS */
1075 static inline int pppoe_proc_init(void) { return 0; }
1076 #endif /* CONFIG_PROC_FS */
1077
1078 static const struct proto_ops pppoe_ops = {
1079     .family             = AF_PPPOX,
1080     .owner              = THIS_MODULE,
1081     .release            = pppoe_release,
1082     .bind               = sock_no_bind,
1083     .connect            = pppoe_connect,
1084     .socketpair         = sock_no_socketpair,
1085     .accept             = sock_no_accept,
1086     .getname            = pppoe_getname,
1087     .poll               = datagram_poll,
1088     .listen             = sock_no_listen,
1089     .shutdown           = sock_no_shutdown,
1090     .setsockopt         = sock_no_setsockopt,
1091     .getsockopt         = sock_no_getsockopt,
1092     .sendmsg            = pppoe_sendmsg,
1093     .recvmsg            = pppoe_recvmsg,
1094     .mmap               = sock_no_mmap,
1095     .ioctl              = pppox_ioctl,
1096 };
1097
1098 static struct pppox_proto pppoe_proto = {
1099     .create     = pppoe_create,
1100     .ioctl      = pppoe_ioctl,
1101     .owner      = THIS_MODULE,
1102 };
1103
1104
1105 static int __init pppoe_init(void)
1106 {
1107         int err = proto_register(&pppoe_sk_proto, 0);
1108
1109         if (err)
1110                 goto out;
1111
1112         err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
1113         if (err)
1114                 goto out_unregister_pppoe_proto;
1115
1116         err = pppoe_proc_init();
1117         if (err)
1118                 goto out_unregister_pppox_proto;
1119
1120         dev_add_pack(&pppoes_ptype);
1121         dev_add_pack(&pppoed_ptype);
1122         register_netdevice_notifier(&pppoe_notifier);
1123 out:
1124         return err;
1125 out_unregister_pppox_proto:
1126         unregister_pppox_proto(PX_PROTO_OE);
1127 out_unregister_pppoe_proto:
1128         proto_unregister(&pppoe_sk_proto);
1129         goto out;
1130 }
1131
1132 static void __exit pppoe_exit(void)
1133 {
1134         unregister_pppox_proto(PX_PROTO_OE);
1135         dev_remove_pack(&pppoes_ptype);
1136         dev_remove_pack(&pppoed_ptype);
1137         unregister_netdevice_notifier(&pppoe_notifier);
1138         remove_proc_entry("net/pppoe", NULL);
1139         proto_unregister(&pppoe_sk_proto);
1140 }
1141
1142 module_init(pppoe_init);
1143 module_exit(pppoe_exit);
1144
1145 MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
1146 MODULE_DESCRIPTION("PPP over Ethernet driver");
1147 MODULE_LICENSE("GPL");
1148 MODULE_ALIAS_NETPROTO(PF_PPPOX);