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