linux/drivers/net/ppp/pppoe.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/** -*- linux-c -*- ***********************************************************
   3 * Linux PPP over Ethernet (PPPoX/PPPoE) Sockets
   4 *
   5 * PPPoX --- Generic PPP encapsulation socket family
   6 * PPPoE --- PPP over Ethernet (RFC 2516)
   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 */
  54
  55#include <linux/string.h>
  56#include <linux/module.h>
  57#include <linux/kernel.h>
  58#include <linux/slab.h>
  59#include <linux/errno.h>
  60#include <linux/netdevice.h>
  61#include <linux/net.h>
  62#include <linux/inetdevice.h>
  63#include <linux/etherdevice.h>
  64#include <linux/skbuff.h>
  65#include <linux/init.h>
  66#include <linux/if_ether.h>
  67#include <linux/if_pppox.h>
  68#include <linux/ppp_channel.h>
  69#include <linux/ppp_defs.h>
  70#include <linux/ppp-ioctl.h>
  71#include <linux/notifier.h>
  72#include <linux/file.h>
  73#include <linux/proc_fs.h>
  74#include <linux/seq_file.h>
  75
  76#include <linux/nsproxy.h>
  77#include <net/net_namespace.h>
  78#include <net/netns/generic.h>
  79#include <net/sock.h>
  80
  81#include <linux/uaccess.h>
  82
  83#define PPPOE_HASH_BITS 4
  84#define PPPOE_HASH_SIZE (1 << PPPOE_HASH_BITS)
  85#define PPPOE_HASH_MASK (PPPOE_HASH_SIZE - 1)
  86
  87static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);
  88
  89static const struct proto_ops pppoe_ops;
  90static const struct ppp_channel_ops pppoe_chan_ops;
  91
  92/* per-net private data for this module */
  93static unsigned int pppoe_net_id __read_mostly;
  94struct pppoe_net {
  95        /*
  96         * we could use _single_ hash table for all
  97         * nets by injecting net id into the hash but
  98         * it would increase hash chains and add
  99         * a few additional math comparations messy
 100         * as well, moreover in case of SMP less locking
 101         * controversy here
 102         */
 103        struct pppox_sock *hash_table[PPPOE_HASH_SIZE];
 104        rwlock_t hash_lock;
 105};
 106
 107/*
 108 * PPPoE could be in the following stages:
 109 * 1) Discovery stage (to obtain remote MAC and Session ID)
 110 * 2) Session stage (MAC and SID are known)
 111 *
 112 * Ethernet frames have a special tag for this but
 113 * we use simpler approach based on session id
 114 */
 115static inline bool stage_session(__be16 sid)
 116{
 117        return sid != 0;
 118}
 119
 120static inline struct pppoe_net *pppoe_pernet(struct net *net)
 121{
 122        return net_generic(net, pppoe_net_id);
 123}
 124
 125static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
 126{
 127        return a->sid == b->sid && ether_addr_equal(a->remote, b->remote);
 128}
 129
 130static inline int cmp_addr(struct pppoe_addr *a, __be16 sid, char *addr)
 131{
 132        return a->sid == sid && ether_addr_equal(a->remote, addr);
 133}
 134
 135#if 8 % PPPOE_HASH_BITS
 136#error 8 must be a multiple of PPPOE_HASH_BITS
 137#endif
 138
 139static int hash_item(__be16 sid, unsigned char *addr)
 140{
 141        unsigned char hash = 0;
 142        unsigned int i;
 143
 144        for (i = 0; i < ETH_ALEN; i++)
 145                hash ^= addr[i];
 146        for (i = 0; i < sizeof(sid_t) * 8; i += 8)
 147                hash ^= (__force __u32)sid >> i;
 148        for (i = 8; (i >>= 1) >= PPPOE_HASH_BITS;)
 149                hash ^= hash >> i;
 150
 151        return hash & PPPOE_HASH_MASK;
 152}
 153
 154/**********************************************************************
 155 *
 156 *  Set/get/delete/rehash items  (internal versions)
 157 *
 158 **********************************************************************/
 159static struct pppox_sock *__get_item(struct pppoe_net *pn, __be16 sid,
 160                                unsigned char *addr, int ifindex)
 161{
 162        int hash = hash_item(sid, addr);
 163        struct pppox_sock *ret;
 164
 165        ret = pn->hash_table[hash];
 166        while (ret) {
 167                if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
 168                    ret->pppoe_ifindex == ifindex)
 169                        return ret;
 170
 171                ret = ret->next;
 172        }
 173
 174        return NULL;
 175}
 176
 177static int __set_item(struct pppoe_net *pn, struct pppox_sock *po)
 178{
 179        int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
 180        struct pppox_sock *ret;
 181
 182        ret = pn->hash_table[hash];
 183        while (ret) {
 184                if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) &&
 185                    ret->pppoe_ifindex == po->pppoe_ifindex)
 186                        return -EALREADY;
 187
 188                ret = ret->next;
 189        }
 190
 191        po->next = pn->hash_table[hash];
 192        pn->hash_table[hash] = po;
 193
 194        return 0;
 195}
 196
 197static void __delete_item(struct pppoe_net *pn, __be16 sid,
 198                                        char *addr, int ifindex)
 199{
 200        int hash = hash_item(sid, addr);
 201        struct pppox_sock *ret, **src;
 202
 203        ret = pn->hash_table[hash];
 204        src = &pn->hash_table[hash];
 205
 206        while (ret) {
 207                if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
 208                    ret->pppoe_ifindex == ifindex) {
 209                        *src = ret->next;
 210                        break;
 211                }
 212
 213                src = &ret->next;
 214                ret = ret->next;
 215        }
 216}
 217
 218/**********************************************************************
 219 *
 220 *  Set/get/delete/rehash items
 221 *
 222 **********************************************************************/
 223static inline struct pppox_sock *get_item(struct pppoe_net *pn, __be16 sid,
 224                                        unsigned char *addr, int ifindex)
 225{
 226        struct pppox_sock *po;
 227
 228        read_lock_bh(&pn->hash_lock);
 229        po = __get_item(pn, sid, addr, ifindex);
 230        if (po)
 231                sock_hold(sk_pppox(po));
 232        read_unlock_bh(&pn->hash_lock);
 233
 234        return po;
 235}
 236
 237static inline struct pppox_sock *get_item_by_addr(struct net *net,
 238                                                struct sockaddr_pppox *sp)
 239{
 240        struct net_device *dev;
 241        struct pppoe_net *pn;
 242        struct pppox_sock *pppox_sock = NULL;
 243
 244        int ifindex;
 245
 246        rcu_read_lock();
 247        dev = dev_get_by_name_rcu(net, sp->sa_addr.pppoe.dev);
 248        if (dev) {
 249                ifindex = dev->ifindex;
 250                pn = pppoe_pernet(net);
 251                pppox_sock = get_item(pn, sp->sa_addr.pppoe.sid,
 252                                sp->sa_addr.pppoe.remote, ifindex);
 253        }
 254        rcu_read_unlock();
 255        return pppox_sock;
 256}
 257
 258static inline void delete_item(struct pppoe_net *pn, __be16 sid,
 259                                        char *addr, int ifindex)
 260{
 261        write_lock_bh(&pn->hash_lock);
 262        __delete_item(pn, sid, addr, ifindex);
 263        write_unlock_bh(&pn->hash_lock);
 264}
 265
 266/***************************************************************************
 267 *
 268 *  Handler for device events.
 269 *  Certain device events require that sockets be unconnected.
 270 *
 271 **************************************************************************/
 272
 273static void pppoe_flush_dev(struct net_device *dev)
 274{
 275        struct pppoe_net *pn;
 276        int i;
 277
 278        pn = pppoe_pernet(dev_net(dev));
 279        write_lock_bh(&pn->hash_lock);
 280        for (i = 0; i < PPPOE_HASH_SIZE; i++) {
 281                struct pppox_sock *po = pn->hash_table[i];
 282                struct sock *sk;
 283
 284                while (po) {
 285                        while (po && po->pppoe_dev != dev) {
 286                                po = po->next;
 287                        }
 288
 289                        if (!po)
 290                                break;
 291
 292                        sk = sk_pppox(po);
 293
 294                        /* We always grab the socket lock, followed by the
 295                         * hash_lock, in that order.  Since we should hold the
 296                         * sock lock while doing any unbinding, we need to
 297                         * release the lock we're holding.  Hold a reference to
 298                         * the sock so it doesn't disappear as we're jumping
 299                         * between locks.
 300                         */
 301
 302                        sock_hold(sk);
 303                        write_unlock_bh(&pn->hash_lock);
 304                        lock_sock(sk);
 305
 306                        if (po->pppoe_dev == dev &&
 307                            sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
 308                                pppox_unbind_sock(sk);
 309                                sk->sk_state_change(sk);
 310                                po->pppoe_dev = NULL;
 311                                dev_put(dev);
 312                        }
 313
 314                        release_sock(sk);
 315                        sock_put(sk);
 316
 317                        /* Restart the process from the start of the current
 318                         * hash chain. We dropped locks so the world may have
 319                         * change from underneath us.
 320                         */
 321
 322                        BUG_ON(pppoe_pernet(dev_net(dev)) == NULL);
 323                        write_lock_bh(&pn->hash_lock);
 324                        po = pn->hash_table[i];
 325                }
 326        }
 327        write_unlock_bh(&pn->hash_lock);
 328}
 329
 330static int pppoe_device_event(struct notifier_block *this,
 331                              unsigned long event, void *ptr)
 332{
 333        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 334
 335        /* Only look at sockets that are using this specific device. */
 336        switch (event) {
 337        case NETDEV_CHANGEADDR:
 338        case NETDEV_CHANGEMTU:
 339                /* A change in mtu or address is a bad thing, requiring
 340                 * LCP re-negotiation.
 341                 */
 342
 343        case NETDEV_GOING_DOWN:
 344        case NETDEV_DOWN:
 345                /* Find every socket on this device and kill it. */
 346                pppoe_flush_dev(dev);
 347                break;
 348
 349        default:
 350                break;
 351        }
 352
 353        return NOTIFY_DONE;
 354}
 355
 356static struct notifier_block pppoe_notifier = {
 357        .notifier_call = pppoe_device_event,
 358};
 359
 360/************************************************************************
 361 *
 362 * Do the real work of receiving a PPPoE Session frame.
 363 *
 364 ***********************************************************************/
 365static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
 366{
 367        struct pppox_sock *po = pppox_sk(sk);
 368        struct pppox_sock *relay_po;
 369
 370        /* Backlog receive. Semantics of backlog rcv preclude any code from
 371         * executing in lock_sock()/release_sock() bounds; meaning sk->sk_state
 372         * can't change.
 373         */
 374
 375        if (skb->pkt_type == PACKET_OTHERHOST)
 376                goto abort_kfree;
 377
 378        if (sk->sk_state & PPPOX_BOUND) {
 379                ppp_input(&po->chan, skb);
 380        } else if (sk->sk_state & PPPOX_RELAY) {
 381                relay_po = get_item_by_addr(sock_net(sk),
 382                                            &po->pppoe_relay);
 383                if (relay_po == NULL)
 384                        goto abort_kfree;
 385
 386                if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
 387                        goto abort_put;
 388
 389                if (!__pppoe_xmit(sk_pppox(relay_po), skb))
 390                        goto abort_put;
 391
 392                sock_put(sk_pppox(relay_po));
 393        } else {
 394                if (sock_queue_rcv_skb(sk, skb))
 395                        goto abort_kfree;
 396        }
 397
 398        return NET_RX_SUCCESS;
 399
 400abort_put:
 401        sock_put(sk_pppox(relay_po));
 402
 403abort_kfree:
 404        kfree_skb(skb);
 405        return NET_RX_DROP;
 406}
 407
 408/************************************************************************
 409 *
 410 * Receive wrapper called in BH context.
 411 *
 412 ***********************************************************************/
 413static int pppoe_rcv(struct sk_buff *skb, struct net_device *dev,
 414                     struct packet_type *pt, struct net_device *orig_dev)
 415{
 416        struct pppoe_hdr *ph;
 417        struct pppox_sock *po;
 418        struct pppoe_net *pn;
 419        int len;
 420
 421        skb = skb_share_check(skb, GFP_ATOMIC);
 422        if (!skb)
 423                goto out;
 424
 425        if (skb_mac_header_len(skb) < ETH_HLEN)
 426                goto drop;
 427
 428        if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
 429                goto drop;
 430
 431        ph = pppoe_hdr(skb);
 432        len = ntohs(ph->length);
 433
 434        skb_pull_rcsum(skb, sizeof(*ph));
 435        if (skb->len < len)
 436                goto drop;
 437
 438        if (pskb_trim_rcsum(skb, len))
 439                goto drop;
 440
 441        ph = pppoe_hdr(skb);
 442        pn = pppoe_pernet(dev_net(dev));
 443
 444        /* Note that get_item does a sock_hold(), so sk_pppox(po)
 445         * is known to be safe.
 446         */
 447        po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
 448        if (!po)
 449                goto drop;
 450
 451        return sk_receive_skb(sk_pppox(po), skb, 0);
 452
 453drop:
 454        kfree_skb(skb);
 455out:
 456        return NET_RX_DROP;
 457}
 458
 459static void pppoe_unbind_sock_work(struct work_struct *work)
 460{
 461        struct pppox_sock *po = container_of(work, struct pppox_sock,
 462                                             proto.pppoe.padt_work);
 463        struct sock *sk = sk_pppox(po);
 464
 465        lock_sock(sk);
 466        if (po->pppoe_dev) {
 467                dev_put(po->pppoe_dev);
 468                po->pppoe_dev = NULL;
 469        }
 470        pppox_unbind_sock(sk);
 471        release_sock(sk);
 472        sock_put(sk);
 473}
 474
 475/************************************************************************
 476 *
 477 * Receive a PPPoE Discovery frame.
 478 * This is solely for detection of PADT frames
 479 *
 480 ***********************************************************************/
 481static int pppoe_disc_rcv(struct sk_buff *skb, struct net_device *dev,
 482                          struct packet_type *pt, struct net_device *orig_dev)
 483
 484{
 485        struct pppoe_hdr *ph;
 486        struct pppox_sock *po;
 487        struct pppoe_net *pn;
 488
 489        skb = skb_share_check(skb, GFP_ATOMIC);
 490        if (!skb)
 491                goto out;
 492
 493        if (skb->pkt_type != PACKET_HOST)
 494                goto abort;
 495
 496        if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
 497                goto abort;
 498
 499        ph = pppoe_hdr(skb);
 500        if (ph->code != PADT_CODE)
 501                goto abort;
 502
 503        pn = pppoe_pernet(dev_net(dev));
 504        po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
 505        if (po)
 506                if (!schedule_work(&po->proto.pppoe.padt_work))
 507                        sock_put(sk_pppox(po));
 508
 509abort:
 510        kfree_skb(skb);
 511out:
 512        return NET_RX_SUCCESS; /* Lies... :-) */
 513}
 514
 515static struct packet_type pppoes_ptype __read_mostly = {
 516        .type   = cpu_to_be16(ETH_P_PPP_SES),
 517        .func   = pppoe_rcv,
 518};
 519
 520static struct packet_type pppoed_ptype __read_mostly = {
 521        .type   = cpu_to_be16(ETH_P_PPP_DISC),
 522        .func   = pppoe_disc_rcv,
 523};
 524
 525static struct proto pppoe_sk_proto __read_mostly = {
 526        .name     = "PPPOE",
 527        .owner    = THIS_MODULE,
 528        .obj_size = sizeof(struct pppox_sock),
 529};
 530
 531/***********************************************************************
 532 *
 533 * Initialize a new struct sock.
 534 *
 535 **********************************************************************/
 536static int pppoe_create(struct net *net, struct socket *sock, int kern)
 537{
 538        struct sock *sk;
 539
 540        sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto, kern);
 541        if (!sk)
 542                return -ENOMEM;
 543
 544        sock_init_data(sock, sk);
 545
 546        sock->state     = SS_UNCONNECTED;
 547        sock->ops       = &pppoe_ops;
 548
 549        sk->sk_backlog_rcv      = pppoe_rcv_core;
 550        sk->sk_state            = PPPOX_NONE;
 551        sk->sk_type             = SOCK_STREAM;
 552        sk->sk_family           = PF_PPPOX;
 553        sk->sk_protocol         = PX_PROTO_OE;
 554
 555        INIT_WORK(&pppox_sk(sk)->proto.pppoe.padt_work,
 556                  pppoe_unbind_sock_work);
 557
 558        return 0;
 559}
 560
 561static int pppoe_release(struct socket *sock)
 562{
 563        struct sock *sk = sock->sk;
 564        struct pppox_sock *po;
 565        struct pppoe_net *pn;
 566        struct net *net = NULL;
 567
 568        if (!sk)
 569                return 0;
 570
 571        lock_sock(sk);
 572        if (sock_flag(sk, SOCK_DEAD)) {
 573                release_sock(sk);
 574                return -EBADF;
 575        }
 576
 577        po = pppox_sk(sk);
 578
 579        if (po->pppoe_dev) {
 580                dev_put(po->pppoe_dev);
 581                po->pppoe_dev = NULL;
 582        }
 583
 584        pppox_unbind_sock(sk);
 585
 586        /* Signal the death of the socket. */
 587        sk->sk_state = PPPOX_DEAD;
 588
 589        net = sock_net(sk);
 590        pn = pppoe_pernet(net);
 591
 592        /*
 593         * protect "po" from concurrent updates
 594         * on pppoe_flush_dev
 595         */
 596        delete_item(pn, po->pppoe_pa.sid, po->pppoe_pa.remote,
 597                    po->pppoe_ifindex);
 598
 599        sock_orphan(sk);
 600        sock->sk = NULL;
 601
 602        skb_queue_purge(&sk->sk_receive_queue);
 603        release_sock(sk);
 604        sock_put(sk);
 605
 606        return 0;
 607}
 608
 609static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
 610                  int sockaddr_len, int flags)
 611{
 612        struct sock *sk = sock->sk;
 613        struct sockaddr_pppox *sp = (struct sockaddr_pppox *)uservaddr;
 614        struct pppox_sock *po = pppox_sk(sk);
 615        struct net_device *dev = NULL;
 616        struct pppoe_net *pn;
 617        struct net *net = NULL;
 618        int error;
 619
 620        lock_sock(sk);
 621
 622        error = -EINVAL;
 623
 624        if (sockaddr_len != sizeof(struct sockaddr_pppox))
 625                goto end;
 626
 627        if (sp->sa_protocol != PX_PROTO_OE)
 628                goto end;
 629
 630        /* Check for already bound sockets */
 631        error = -EBUSY;
 632        if ((sk->sk_state & PPPOX_CONNECTED) &&
 633             stage_session(sp->sa_addr.pppoe.sid))
 634                goto end;
 635
 636        /* Check for already disconnected sockets, on attempts to disconnect */
 637        error = -EALREADY;
 638        if ((sk->sk_state & PPPOX_DEAD) &&
 639             !stage_session(sp->sa_addr.pppoe.sid))
 640                goto end;
 641
 642        error = 0;
 643
 644        /* Delete the old binding */
 645        if (stage_session(po->pppoe_pa.sid)) {
 646                pppox_unbind_sock(sk);
 647                pn = pppoe_pernet(sock_net(sk));
 648                delete_item(pn, po->pppoe_pa.sid,
 649                            po->pppoe_pa.remote, po->pppoe_ifindex);
 650                if (po->pppoe_dev) {
 651                        dev_put(po->pppoe_dev);
 652                        po->pppoe_dev = NULL;
 653                }
 654
 655                po->pppoe_ifindex = 0;
 656                memset(&po->pppoe_pa, 0, sizeof(po->pppoe_pa));
 657                memset(&po->pppoe_relay, 0, sizeof(po->pppoe_relay));
 658                memset(&po->chan, 0, sizeof(po->chan));
 659                po->next = NULL;
 660                po->num = 0;
 661
 662                sk->sk_state = PPPOX_NONE;
 663        }
 664
 665        /* Re-bind in session stage only */
 666        if (stage_session(sp->sa_addr.pppoe.sid)) {
 667                error = -ENODEV;
 668                net = sock_net(sk);
 669                dev = dev_get_by_name(net, sp->sa_addr.pppoe.dev);
 670                if (!dev)
 671                        goto err_put;
 672
 673                po->pppoe_dev = dev;
 674                po->pppoe_ifindex = dev->ifindex;
 675                pn = pppoe_pernet(net);
 676                if (!(dev->flags & IFF_UP)) {
 677                        goto err_put;
 678                }
 679
 680                memcpy(&po->pppoe_pa,
 681                       &sp->sa_addr.pppoe,
 682                       sizeof(struct pppoe_addr));
 683
 684                write_lock_bh(&pn->hash_lock);
 685                error = __set_item(pn, po);
 686                write_unlock_bh(&pn->hash_lock);
 687                if (error < 0)
 688                        goto err_put;
 689
 690                po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
 691                                   dev->hard_header_len);
 692
 693                po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr) - 2;
 694                po->chan.private = sk;
 695                po->chan.ops = &pppoe_chan_ops;
 696
 697                error = ppp_register_net_channel(dev_net(dev), &po->chan);
 698                if (error) {
 699                        delete_item(pn, po->pppoe_pa.sid,
 700                                    po->pppoe_pa.remote, po->pppoe_ifindex);
 701                        goto err_put;
 702                }
 703
 704                sk->sk_state = PPPOX_CONNECTED;
 705        }
 706
 707        po->num = sp->sa_addr.pppoe.sid;
 708
 709end:
 710        release_sock(sk);
 711        return error;
 712err_put:
 713        if (po->pppoe_dev) {
 714                dev_put(po->pppoe_dev);
 715                po->pppoe_dev = NULL;
 716        }
 717        goto end;
 718}
 719
 720static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
 721                  int peer)
 722{
 723        int len = sizeof(struct sockaddr_pppox);
 724        struct sockaddr_pppox sp;
 725
 726        sp.sa_family    = AF_PPPOX;
 727        sp.sa_protocol  = PX_PROTO_OE;
 728        memcpy(&sp.sa_addr.pppoe, &pppox_sk(sock->sk)->pppoe_pa,
 729               sizeof(struct pppoe_addr));
 730
 731        memcpy(uaddr, &sp, len);
 732
 733        return len;
 734}
 735
 736static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
 737                unsigned long arg)
 738{
 739        struct sock *sk = sock->sk;
 740        struct pppox_sock *po = pppox_sk(sk);
 741        int val;
 742        int err;
 743
 744        switch (cmd) {
 745        case PPPIOCGMRU:
 746                err = -ENXIO;
 747                if (!(sk->sk_state & PPPOX_CONNECTED))
 748                        break;
 749
 750                err = -EFAULT;
 751                if (put_user(po->pppoe_dev->mtu -
 752                             sizeof(struct pppoe_hdr) -
 753                             PPP_HDRLEN,
 754                             (int __user *)arg))
 755                        break;
 756                err = 0;
 757                break;
 758
 759        case PPPIOCSMRU:
 760                err = -ENXIO;
 761                if (!(sk->sk_state & PPPOX_CONNECTED))
 762                        break;
 763
 764                err = -EFAULT;
 765                if (get_user(val, (int __user *)arg))
 766                        break;
 767
 768                if (val < (po->pppoe_dev->mtu
 769                           - sizeof(struct pppoe_hdr)
 770                           - PPP_HDRLEN))
 771                        err = 0;
 772                else
 773                        err = -EINVAL;
 774                break;
 775
 776        case PPPIOCSFLAGS:
 777                err = -EFAULT;
 778                if (get_user(val, (int __user *)arg))
 779                        break;
 780                err = 0;
 781                break;
 782
 783        case PPPOEIOCSFWD:
 784        {
 785                struct pppox_sock *relay_po;
 786
 787                err = -EBUSY;
 788                if (sk->sk_state & (PPPOX_BOUND | PPPOX_DEAD))
 789                        break;
 790
 791                err = -ENOTCONN;
 792                if (!(sk->sk_state & PPPOX_CONNECTED))
 793                        break;
 794
 795                /* PPPoE address from the user specifies an outbound
 796                   PPPoE address which frames are forwarded to */
 797                err = -EFAULT;
 798                if (copy_from_user(&po->pppoe_relay,
 799                                   (void __user *)arg,
 800                                   sizeof(struct sockaddr_pppox)))
 801                        break;
 802
 803                err = -EINVAL;
 804                if (po->pppoe_relay.sa_family != AF_PPPOX ||
 805                    po->pppoe_relay.sa_protocol != PX_PROTO_OE)
 806                        break;
 807
 808                /* Check that the socket referenced by the address
 809                   actually exists. */
 810                relay_po = get_item_by_addr(sock_net(sk), &po->pppoe_relay);
 811                if (!relay_po)
 812                        break;
 813
 814                sock_put(sk_pppox(relay_po));
 815                sk->sk_state |= PPPOX_RELAY;
 816                err = 0;
 817                break;
 818        }
 819
 820        case PPPOEIOCDFWD:
 821                err = -EALREADY;
 822                if (!(sk->sk_state & PPPOX_RELAY))
 823                        break;
 824
 825                sk->sk_state &= ~PPPOX_RELAY;
 826                err = 0;
 827                break;
 828
 829        default:
 830                err = -ENOTTY;
 831        }
 832
 833        return err;
 834}
 835
 836static int pppoe_sendmsg(struct socket *sock, struct msghdr *m,
 837                         size_t total_len)
 838{
 839        struct sk_buff *skb;
 840        struct sock *sk = sock->sk;
 841        struct pppox_sock *po = pppox_sk(sk);
 842        int error;
 843        struct pppoe_hdr hdr;
 844        struct pppoe_hdr *ph;
 845        struct net_device *dev;
 846        char *start;
 847        int hlen;
 848
 849        lock_sock(sk);
 850        if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) {
 851                error = -ENOTCONN;
 852                goto end;
 853        }
 854
 855        hdr.ver = 1;
 856        hdr.type = 1;
 857        hdr.code = 0;
 858        hdr.sid = po->num;
 859
 860        dev = po->pppoe_dev;
 861
 862        error = -EMSGSIZE;
 863        if (total_len > (dev->mtu + dev->hard_header_len))
 864                goto end;
 865
 866        hlen = LL_RESERVED_SPACE(dev);
 867        skb = sock_wmalloc(sk, hlen + sizeof(*ph) + total_len +
 868                           dev->needed_tailroom, 0, GFP_KERNEL);
 869        if (!skb) {
 870                error = -ENOMEM;
 871                goto end;
 872        }
 873
 874        /* Reserve space for headers. */
 875        skb_reserve(skb, hlen);
 876        skb_reset_network_header(skb);
 877
 878        skb->dev = dev;
 879
 880        skb->priority = sk->sk_priority;
 881        skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
 882
 883        ph = skb_put(skb, total_len + sizeof(struct pppoe_hdr));
 884        start = (char *)&ph->tag[0];
 885
 886        error = memcpy_from_msg(start, m, total_len);
 887        if (error < 0) {
 888                kfree_skb(skb);
 889                goto end;
 890        }
 891
 892        error = total_len;
 893        dev_hard_header(skb, dev, ETH_P_PPP_SES,
 894                        po->pppoe_pa.remote, NULL, total_len);
 895
 896        memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
 897
 898        ph->length = htons(total_len);
 899
 900        dev_queue_xmit(skb);
 901
 902end:
 903        release_sock(sk);
 904        return error;
 905}
 906
 907/************************************************************************
 908 *
 909 * xmit function for internal use.
 910 *
 911 ***********************************************************************/
 912static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
 913{
 914        struct pppox_sock *po = pppox_sk(sk);
 915        struct net_device *dev = po->pppoe_dev;
 916        struct pppoe_hdr *ph;
 917        int data_len = skb->len;
 918
 919        /* The higher-level PPP code (ppp_unregister_channel()) ensures the PPP
 920         * xmit operations conclude prior to an unregistration call.  Thus
 921         * sk->sk_state cannot change, so we don't need to do lock_sock().
 922         * But, we also can't do a lock_sock since that introduces a potential
 923         * deadlock as we'd reverse the lock ordering used when calling
 924         * ppp_unregister_channel().
 925         */
 926
 927        if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 928                goto abort;
 929
 930        if (!dev)
 931                goto abort;
 932
 933        /* Copy the data if there is no space for the header or if it's
 934         * read-only.
 935         */
 936        if (skb_cow_head(skb, LL_RESERVED_SPACE(dev) + sizeof(*ph)))
 937                goto abort;
 938
 939        __skb_push(skb, sizeof(*ph));
 940        skb_reset_network_header(skb);
 941
 942        ph = pppoe_hdr(skb);
 943        ph->ver = 1;
 944        ph->type = 1;
 945        ph->code = 0;
 946        ph->sid = po->num;
 947        ph->length = htons(data_len);
 948
 949        skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
 950        skb->dev = dev;
 951
 952        dev_hard_header(skb, dev, ETH_P_PPP_SES,
 953                        po->pppoe_pa.remote, NULL, data_len);
 954
 955        dev_queue_xmit(skb);
 956        return 1;
 957
 958abort:
 959        kfree_skb(skb);
 960        return 1;
 961}
 962
 963/************************************************************************
 964 *
 965 * xmit function called by generic PPP driver
 966 * sends PPP frame over PPPoE socket
 967 *
 968 ***********************************************************************/
 969static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 970{
 971        struct sock *sk = (struct sock *)chan->private;
 972        return __pppoe_xmit(sk, skb);
 973}
 974
 975static const struct ppp_channel_ops pppoe_chan_ops = {
 976        .start_xmit = pppoe_xmit,
 977};
 978
 979static int pppoe_recvmsg(struct socket *sock, struct msghdr *m,
 980                         size_t total_len, int flags)
 981{
 982        struct sock *sk = sock->sk;
 983        struct sk_buff *skb;
 984        int error = 0;
 985
 986        if (sk->sk_state & PPPOX_BOUND) {
 987                error = -EIO;
 988                goto end;
 989        }
 990
 991        skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 992                                flags & MSG_DONTWAIT, &error);
 993        if (error < 0)
 994                goto end;
 995
 996        if (skb) {
 997                total_len = min_t(size_t, total_len, skb->len);
 998                error = skb_copy_datagram_msg(skb, 0, m, total_len);
 999                if (error == 0) {
1000                        consume_skb(skb);
1001                        return total_len;
1002                }
1003        }
1004
1005        kfree_skb(skb);
1006end:
1007        return error;
1008}
1009
1010#ifdef CONFIG_PROC_FS
1011static int pppoe_seq_show(struct seq_file *seq, void *v)
1012{
1013        struct pppox_sock *po;
1014        char *dev_name;
1015
1016        if (v == SEQ_START_TOKEN) {
1017                seq_puts(seq, "Id       Address              Device\n");
1018                goto out;
1019        }
1020
1021        po = v;
1022        dev_name = po->pppoe_pa.dev;
1023
1024        seq_printf(seq, "%08X %pM %8s\n",
1025                po->pppoe_pa.sid, po->pppoe_pa.remote, dev_name);
1026out:
1027        return 0;
1028}
1029
1030static inline struct pppox_sock *pppoe_get_idx(struct pppoe_net *pn, loff_t pos)
1031{
1032        struct pppox_sock *po;
1033        int i;
1034
1035        for (i = 0; i < PPPOE_HASH_SIZE; i++) {
1036                po = pn->hash_table[i];
1037                while (po) {
1038                        if (!pos--)
1039                                goto out;
1040                        po = po->next;
1041                }
1042        }
1043
1044out:
1045        return po;
1046}
1047
1048static void *pppoe_seq_start(struct seq_file *seq, loff_t *pos)
1049        __acquires(pn->hash_lock)
1050{
1051        struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1052        loff_t l = *pos;
1053
1054        read_lock_bh(&pn->hash_lock);
1055        return l ? pppoe_get_idx(pn, --l) : SEQ_START_TOKEN;
1056}
1057
1058static void *pppoe_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1059{
1060        struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1061        struct pppox_sock *po;
1062
1063        ++*pos;
1064        if (v == SEQ_START_TOKEN) {
1065                po = pppoe_get_idx(pn, 0);
1066                goto out;
1067        }
1068        po = v;
1069        if (po->next)
1070                po = po->next;
1071        else {
1072                int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
1073
1074                po = NULL;
1075                while (++hash < PPPOE_HASH_SIZE) {
1076                        po = pn->hash_table[hash];
1077                        if (po)
1078                                break;
1079                }
1080        }
1081
1082out:
1083        return po;
1084}
1085
1086static void pppoe_seq_stop(struct seq_file *seq, void *v)
1087        __releases(pn->hash_lock)
1088{
1089        struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1090        read_unlock_bh(&pn->hash_lock);
1091}
1092
1093static const struct seq_operations pppoe_seq_ops = {
1094        .start          = pppoe_seq_start,
1095        .next           = pppoe_seq_next,
1096        .stop           = pppoe_seq_stop,
1097        .show           = pppoe_seq_show,
1098};
1099#endif /* CONFIG_PROC_FS */
1100
1101static const struct proto_ops pppoe_ops = {
1102        .family         = AF_PPPOX,
1103        .owner          = THIS_MODULE,
1104        .release        = pppoe_release,
1105        .bind           = sock_no_bind,
1106        .connect        = pppoe_connect,
1107        .socketpair     = sock_no_socketpair,
1108        .accept         = sock_no_accept,
1109        .getname        = pppoe_getname,
1110        .poll           = datagram_poll,
1111        .listen         = sock_no_listen,
1112        .shutdown       = sock_no_shutdown,
1113        .sendmsg        = pppoe_sendmsg,
1114        .recvmsg        = pppoe_recvmsg,
1115        .mmap           = sock_no_mmap,
1116        .ioctl          = pppox_ioctl,
1117#ifdef CONFIG_COMPAT
1118        .compat_ioctl   = pppox_compat_ioctl,
1119#endif
1120};
1121
1122static const struct pppox_proto pppoe_proto = {
1123        .create = pppoe_create,
1124        .ioctl  = pppoe_ioctl,
1125        .owner  = THIS_MODULE,
1126};
1127
1128static __net_init int pppoe_init_net(struct net *net)
1129{
1130        struct pppoe_net *pn = pppoe_pernet(net);
1131        struct proc_dir_entry *pde;
1132
1133        rwlock_init(&pn->hash_lock);
1134
1135        pde = proc_create_net("pppoe", 0444, net->proc_net,
1136                        &pppoe_seq_ops, sizeof(struct seq_net_private));
1137#ifdef CONFIG_PROC_FS
1138        if (!pde)
1139                return -ENOMEM;
1140#endif
1141
1142        return 0;
1143}
1144
1145static __net_exit void pppoe_exit_net(struct net *net)
1146{
1147        remove_proc_entry("pppoe", net->proc_net);
1148}
1149
1150static struct pernet_operations pppoe_net_ops = {
1151        .init = pppoe_init_net,
1152        .exit = pppoe_exit_net,
1153        .id   = &pppoe_net_id,
1154        .size = sizeof(struct pppoe_net),
1155};
1156
1157static int __init pppoe_init(void)
1158{
1159        int err;
1160
1161        err = register_pernet_device(&pppoe_net_ops);
1162        if (err)
1163                goto out;
1164
1165        err = proto_register(&pppoe_sk_proto, 0);
1166        if (err)
1167                goto out_unregister_net_ops;
1168
1169        err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
1170        if (err)
1171                goto out_unregister_pppoe_proto;
1172
1173        dev_add_pack(&pppoes_ptype);
1174        dev_add_pack(&pppoed_ptype);
1175        register_netdevice_notifier(&pppoe_notifier);
1176
1177        return 0;
1178
1179out_unregister_pppoe_proto:
1180        proto_unregister(&pppoe_sk_proto);
1181out_unregister_net_ops:
1182        unregister_pernet_device(&pppoe_net_ops);
1183out:
1184        return err;
1185}
1186
1187static void __exit pppoe_exit(void)
1188{
1189        unregister_netdevice_notifier(&pppoe_notifier);
1190        dev_remove_pack(&pppoed_ptype);
1191        dev_remove_pack(&pppoes_ptype);
1192        unregister_pppox_proto(PX_PROTO_OE);
1193        proto_unregister(&pppoe_sk_proto);
1194        unregister_pernet_device(&pppoe_net_ops);
1195}
1196
1197module_init(pppoe_init);
1198module_exit(pppoe_exit);
1199
1200MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
1201MODULE_DESCRIPTION("PPP over Ethernet driver");
1202MODULE_LICENSE("GPL");
1203MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OE);
1204