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pppoe.c

/** -*- linux-c -*- ***********************************************************
 * Linux PPP over Ethernet (PPPoX/PPPoE) Sockets
 *
 * PPPoX --- Generic PPP encapsulation socket family
 * PPPoE --- PPP over Ethernet (RFC 2516)
 *
 *
 * Version: 0.7.0
 *
 * 070228 : Fix to allow multiple sessions with same remote MAC and same
 *          session id by including the local device ifindex in the
 *          tuple identifying a session. This also ensures packets can't
 *          be injected into a session from interfaces other than the one
 *          specified by userspace. Florian Zumbiehl <florz@florz.de>
 *          (Oh, BTW, this one is YYMMDD, in case you were wondering ...)
 * 220102 : Fix module use count on failure in pppoe_create, pppox_sk -acme
 * 030700 : Fixed connect logic to allow for disconnect.
 * 270700 : Fixed potential SMP problems; we must protect against
 *          simultaneous invocation of ppp_input
 *          and ppp_unregister_channel.
 * 040800 : Respect reference count mechanisms on net-devices.
 * 200800 : fix kfree(skb) in pppoe_rcv (acme)
 *          Module reference count is decremented in the right spot now,
 *          guards against sock_put not actually freeing the sk
 *          in pppoe_release.
 * 051000 : Initialization cleanup.
 * 111100 : Fix recvmsg.
 * 050101 : Fix PADT procesing.
 * 140501 : Use pppoe_rcv_core to handle all backlog. (Alexey)
 * 170701 : Do not lock_sock with rwlock held. (DaveM)
 *          Ignore discovery frames if user has socket
 *          locked. (DaveM)
 *          Ignore return value of dev_queue_xmit in __pppoe_xmit
 *          or else we may kfree an SKB twice. (DaveM)
 * 190701 : When doing copies of skb's in __pppoe_xmit, always delete
 *          the original skb that was passed in on success, never on
 *          failure.  Delete the copy of the skb on failure to avoid
 *          a memory leak.
 * 081001 : Misc. cleanup (licence string, non-blocking, prevent
 *          reference of device on close).
 * 121301 : New ppp channels interface; cannot unregister a channel
 *          from interrupts.  Thus, we mark the socket as a ZOMBIE
 *          and do the unregistration later.
 * 081002 : seq_file support for proc stuff -acme
 * 111602 : Merge all 2.4 fixes into 2.5/2.6 tree.  Label 2.5/2.6
 *          as version 0.7.  Spacing cleanup.
 * Author:  Michal Ostrowski <mostrows@speakeasy.net>
 * Contributors:
 *          Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *          David S. Miller (davem@redhat.com)
 *
 * License:
 *          This program is free software; you can redistribute it and/or
 *          modify it under the terms of the GNU General Public License
 *          as published by the Free Software Foundation; either version
 *          2 of the License, or (at your option) any later version.
 *
 */

#include <linux/string.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/net.h>
#include <linux/inetdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/if_ether.h>
#include <linux/if_pppox.h>
#include <linux/ppp_channel.h>
#include <linux/ppp_defs.h>
#include <linux/if_ppp.h>
#include <linux/notifier.h>
#include <linux/file.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

#include <net/net_namespace.h>
#include <net/sock.h>

#include <asm/uaccess.h>

#define PPPOE_HASH_BITS 4
#define PPPOE_HASH_SIZE (1<<PPPOE_HASH_BITS)

static struct ppp_channel_ops pppoe_chan_ops;

static int pppoe_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb);
static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);

static const struct proto_ops pppoe_ops;
static DEFINE_RWLOCK(pppoe_hash_lock);

static struct ppp_channel_ops pppoe_chan_ops;

static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
{
      return (a->sid == b->sid &&
            (memcmp(a->remote, b->remote, ETH_ALEN) == 0));
}

static inline int cmp_addr(struct pppoe_addr *a, __be16 sid, char *addr)
{
      return (a->sid == sid &&
            (memcmp(a->remote,addr,ETH_ALEN) == 0));
}

#if 8%PPPOE_HASH_BITS
#error 8 must be a multiple of PPPOE_HASH_BITS
#endif

static int hash_item(__be16 sid, unsigned char *addr)
{
      unsigned char hash = 0;
      unsigned int i;

      for (i = 0 ; i < ETH_ALEN ; i++) {
            hash ^= addr[i];
      }
      for (i = 0 ; i < sizeof(sid_t)*8 ; i += 8 ){
            hash ^= (__force __u32)sid>>i;
      }
      for (i = 8 ; (i>>=1) >= PPPOE_HASH_BITS ; ) {
            hash ^= hash>>i;
      }

      return hash & ( PPPOE_HASH_SIZE - 1 );
}

/* zeroed because its in .bss */
static struct pppox_sock *item_hash_table[PPPOE_HASH_SIZE];

/**********************************************************************
 *
 *  Set/get/delete/rehash items  (internal versions)
 *
 **********************************************************************/
static struct pppox_sock *__get_item(__be16 sid, unsigned char *addr, int ifindex)
{
      int hash = hash_item(sid, addr);
      struct pppox_sock *ret;

      ret = item_hash_table[hash];

      while (ret && !(cmp_addr(&ret->pppoe_pa, sid, addr) && ret->pppoe_ifindex == ifindex))
            ret = ret->next;

      return ret;
}

static int __set_item(struct pppox_sock *po)
{
      int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
      struct pppox_sock *ret;

      ret = item_hash_table[hash];
      while (ret) {
            if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) && ret->pppoe_ifindex == po->pppoe_ifindex)
                  return -EALREADY;

            ret = ret->next;
      }

      po->next = item_hash_table[hash];
      item_hash_table[hash] = po;

      return 0;
}

static struct pppox_sock *__delete_item(__be16 sid, char *addr, int ifindex)
{
      int hash = hash_item(sid, addr);
      struct pppox_sock *ret, **src;

      ret = item_hash_table[hash];
      src = &item_hash_table[hash];

      while (ret) {
            if (cmp_addr(&ret->pppoe_pa, sid, addr) && ret->pppoe_ifindex == ifindex) {
                  *src = ret->next;
                  break;
            }

            src = &ret->next;
            ret = ret->next;
      }

      return ret;
}

/**********************************************************************
 *
 *  Set/get/delete/rehash items
 *
 **********************************************************************/
static inline struct pppox_sock *get_item(__be16 sid,
                               unsigned char *addr, int ifindex)
{
      struct pppox_sock *po;

      read_lock_bh(&pppoe_hash_lock);
      po = __get_item(sid, addr, ifindex);
      if (po)
            sock_hold(sk_pppox(po));
      read_unlock_bh(&pppoe_hash_lock);

      return po;
}

static inline struct pppox_sock *get_item_by_addr(struct sockaddr_pppox *sp)
{
      struct net_device *dev;
      int ifindex;

      dev = dev_get_by_name(&init_net, sp->sa_addr.pppoe.dev);
      if(!dev)
            return NULL;
      ifindex = dev->ifindex;
      dev_put(dev);
      return get_item(sp->sa_addr.pppoe.sid, sp->sa_addr.pppoe.remote, ifindex);
}

static inline struct pppox_sock *delete_item(__be16 sid, char *addr, int ifindex)
{
      struct pppox_sock *ret;

      write_lock_bh(&pppoe_hash_lock);
      ret = __delete_item(sid, addr, ifindex);
      write_unlock_bh(&pppoe_hash_lock);

      return ret;
}



/***************************************************************************
 *
 *  Handler for device events.
 *  Certain device events require that sockets be unconnected.
 *
 **************************************************************************/

static void pppoe_flush_dev(struct net_device *dev)
{
      int hash;
      BUG_ON(dev == NULL);

      write_lock_bh(&pppoe_hash_lock);
      for (hash = 0; hash < PPPOE_HASH_SIZE; hash++) {
            struct pppox_sock *po = item_hash_table[hash];

            while (po != NULL) {
                  struct sock *sk = sk_pppox(po);
                  if (po->pppoe_dev != dev) {
                        po = po->next;
                        continue;
                  }
                  po->pppoe_dev = NULL;
                  dev_put(dev);


                  /* We always grab the socket lock, followed by the
                   * pppoe_hash_lock, in that order.  Since we should
                   * hold the sock lock while doing any unbinding,
                   * we need to release the lock we're holding.
                   * Hold a reference to the sock so it doesn't disappear
                   * as we're jumping between locks.
                   */

                  sock_hold(sk);

                  write_unlock_bh(&pppoe_hash_lock);
                  lock_sock(sk);

                  if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
                        pppox_unbind_sock(sk);
                        sk->sk_state = PPPOX_ZOMBIE;
                        sk->sk_state_change(sk);
                  }

                  release_sock(sk);
                  sock_put(sk);

                  /* Restart scan at the beginning of this hash chain.
                   * While the lock was dropped the chain contents may
                   * have changed.
                   */
                  write_lock_bh(&pppoe_hash_lock);
                  po = item_hash_table[hash];
            }
      }
      write_unlock_bh(&pppoe_hash_lock);
}

static int pppoe_device_event(struct notifier_block *this,
                        unsigned long event, void *ptr)
{
      struct net_device *dev = (struct net_device *) ptr;

      if (dev->nd_net != &init_net)
            return NOTIFY_DONE;

      /* Only look at sockets that are using this specific device. */
      switch (event) {
      case NETDEV_CHANGEMTU:
            /* A change in mtu is a bad thing, requiring
             * LCP re-negotiation.
             */

      case NETDEV_GOING_DOWN:
      case NETDEV_DOWN:
            /* Find every socket on this device and kill it. */
            pppoe_flush_dev(dev);
            break;

      default:
            break;
      };

      return NOTIFY_DONE;
}


static struct notifier_block pppoe_notifier = {
      .notifier_call = pppoe_device_event,
};


/************************************************************************
 *
 * Do the real work of receiving a PPPoE Session frame.
 *
 ***********************************************************************/
static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
{
      struct pppox_sock *po = pppox_sk(sk);
      struct pppox_sock *relay_po;

      if (sk->sk_state & PPPOX_BOUND) {
            struct pppoe_hdr *ph = pppoe_hdr(skb);
            int len = ntohs(ph->length);
            skb_pull_rcsum(skb, sizeof(struct pppoe_hdr));
            if (pskb_trim_rcsum(skb, len))
                  goto abort_kfree;

            ppp_input(&po->chan, skb);
      } else if (sk->sk_state & PPPOX_RELAY) {
            relay_po = get_item_by_addr(&po->pppoe_relay);

            if (relay_po == NULL)
                  goto abort_kfree;

            if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
                  goto abort_put;

            skb_pull(skb, sizeof(struct pppoe_hdr));
            if (!__pppoe_xmit(sk_pppox(relay_po), skb))
                  goto abort_put;
      } else {
            if (sock_queue_rcv_skb(sk, skb))
                  goto abort_kfree;
      }

      return NET_RX_SUCCESS;

abort_put:
      sock_put(sk_pppox(relay_po));

abort_kfree:
      kfree_skb(skb);
      return NET_RX_DROP;
}

/************************************************************************
 *
 * Receive wrapper called in BH context.
 *
 ***********************************************************************/
static int pppoe_rcv(struct sk_buff *skb,
                 struct net_device *dev,
                 struct packet_type *pt,
                 struct net_device *orig_dev)

{
      struct pppoe_hdr *ph;
      struct pppox_sock *po;

      if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
            goto out;

      if (dev->nd_net != &init_net)
            goto drop;

      if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
            goto drop;

      ph = pppoe_hdr(skb);

      po = get_item(ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
      if (po != NULL)
            return sk_receive_skb(sk_pppox(po), skb, 0);
drop:
      kfree_skb(skb);
out:
      return NET_RX_DROP;
}

/************************************************************************
 *
 * Receive a PPPoE Discovery frame.
 * This is solely for detection of PADT frames
 *
 ***********************************************************************/
static int pppoe_disc_rcv(struct sk_buff *skb,
                    struct net_device *dev,
                    struct packet_type *pt,
                    struct net_device *orig_dev)

{
      struct pppoe_hdr *ph;
      struct pppox_sock *po;

      if (dev->nd_net != &init_net)
            goto abort;

      if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
            goto abort;

      if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
            goto out;

      ph = pppoe_hdr(skb);
      if (ph->code != PADT_CODE)
            goto abort;

      po = get_item(ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
      if (po) {
            struct sock *sk = sk_pppox(po);

            bh_lock_sock(sk);

            /* If the user has locked the socket, just ignore
             * the packet.  With the way two rcv protocols hook into
             * one socket family type, we cannot (easily) distinguish
             * what kind of SKB it is during backlog rcv.
             */
            if (sock_owned_by_user(sk) == 0) {
                  /* We're no longer connect at the PPPOE layer,
                   * and must wait for ppp channel to disconnect us.
                   */
                  sk->sk_state = PPPOX_ZOMBIE;
            }

            bh_unlock_sock(sk);
            sock_put(sk);
      }

abort:
      kfree_skb(skb);
out:
      return NET_RX_SUCCESS; /* Lies... :-) */
}

static struct packet_type pppoes_ptype = {
      .type = __constant_htons(ETH_P_PPP_SES),
      .func = pppoe_rcv,
};

static struct packet_type pppoed_ptype = {
      .type = __constant_htons(ETH_P_PPP_DISC),
      .func = pppoe_disc_rcv,
};

static struct proto pppoe_sk_proto = {
      .name   = "PPPOE",
      .owner        = THIS_MODULE,
      .obj_size = sizeof(struct pppox_sock),
};

/***********************************************************************
 *
 * Initialize a new struct sock.
 *
 **********************************************************************/
static int pppoe_create(struct net *net, struct socket *sock)
{
      int error = -ENOMEM;
      struct sock *sk;

      sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto);
      if (!sk)
            goto out;

      sock_init_data(sock, sk);

      sock->state = SS_UNCONNECTED;
      sock->ops   = &pppoe_ops;

      sk->sk_backlog_rcv = pppoe_rcv_core;
      sk->sk_state         = PPPOX_NONE;
      sk->sk_type    = SOCK_STREAM;
      sk->sk_family        = PF_PPPOX;
      sk->sk_protocol      = PX_PROTO_OE;

      error = 0;
out:  return error;
}

static int pppoe_release(struct socket *sock)
{
      struct sock *sk = sock->sk;
      struct pppox_sock *po;

      if (!sk)
            return 0;

      lock_sock(sk);
      if (sock_flag(sk, SOCK_DEAD)){
            release_sock(sk);
            return -EBADF;
      }

      pppox_unbind_sock(sk);

      /* Signal the death of the socket. */
      sk->sk_state = PPPOX_DEAD;


      /* Write lock on hash lock protects the entire "po" struct from
       * concurrent updates via pppoe_flush_dev. The "po" struct should
       * be considered part of the hash table contents, thus protected
       * by the hash table lock */
      write_lock_bh(&pppoe_hash_lock);

      po = pppox_sk(sk);
      if (po->pppoe_pa.sid) {
            __delete_item(po->pppoe_pa.sid,
                        po->pppoe_pa.remote, po->pppoe_ifindex);
      }

      if (po->pppoe_dev) {
            dev_put(po->pppoe_dev);
            po->pppoe_dev = NULL;
      }

      write_unlock_bh(&pppoe_hash_lock);

      sock_orphan(sk);
      sock->sk = NULL;

      skb_queue_purge(&sk->sk_receive_queue);
      release_sock(sk);
      sock_put(sk);

      return 0;
}


static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
              int sockaddr_len, int flags)
{
      struct sock *sk = sock->sk;
      struct net_device *dev;
      struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
      struct pppox_sock *po = pppox_sk(sk);
      int error;

      lock_sock(sk);

      error = -EINVAL;
      if (sp->sa_protocol != PX_PROTO_OE)
            goto end;

      /* Check for already bound sockets */
      error = -EBUSY;
      if ((sk->sk_state & PPPOX_CONNECTED) && sp->sa_addr.pppoe.sid)
            goto end;

      /* Check for already disconnected sockets, on attempts to disconnect */
      error = -EALREADY;
      if ((sk->sk_state & PPPOX_DEAD) && !sp->sa_addr.pppoe.sid )
            goto end;

      error = 0;
      if (po->pppoe_pa.sid) {
            pppox_unbind_sock(sk);

            /* Delete the old binding */
            delete_item(po->pppoe_pa.sid,po->pppoe_pa.remote,po->pppoe_ifindex);

            if(po->pppoe_dev)
                  dev_put(po->pppoe_dev);

            memset(sk_pppox(po) + 1, 0,
                   sizeof(struct pppox_sock) - sizeof(struct sock));

            sk->sk_state = PPPOX_NONE;
      }

      /* Don't re-bind if sid==0 */
      if (sp->sa_addr.pppoe.sid != 0) {
            dev = dev_get_by_name(&init_net, sp->sa_addr.pppoe.dev);

            error = -ENODEV;
            if (!dev)
                  goto end;

            po->pppoe_dev = dev;
            po->pppoe_ifindex = dev->ifindex;

            write_lock_bh(&pppoe_hash_lock);
            if (!(dev->flags & IFF_UP)){
                  write_unlock_bh(&pppoe_hash_lock);
                  goto err_put;
            }

            memcpy(&po->pppoe_pa,
                   &sp->sa_addr.pppoe,
                   sizeof(struct pppoe_addr));

            error = __set_item(po);
            write_unlock_bh(&pppoe_hash_lock);
            if (error < 0)
                  goto err_put;

            po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
                           dev->hard_header_len);

            po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr);
            po->chan.private = sk;
            po->chan.ops = &pppoe_chan_ops;

            error = ppp_register_channel(&po->chan);
            if (error)
                  goto err_put;

            sk->sk_state = PPPOX_CONNECTED;
      }

      po->num = sp->sa_addr.pppoe.sid;

 end:
      release_sock(sk);
      return error;
err_put:
      if (po->pppoe_dev) {
            dev_put(po->pppoe_dev);
            po->pppoe_dev = NULL;
      }
      goto end;
}


static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
              int *usockaddr_len, int peer)
{
      int len = sizeof(struct sockaddr_pppox);
      struct sockaddr_pppox sp;

      sp.sa_family      = AF_PPPOX;
      sp.sa_protocol    = PX_PROTO_OE;
      memcpy(&sp.sa_addr.pppoe, &pppox_sk(sock->sk)->pppoe_pa,
             sizeof(struct pppoe_addr));

      memcpy(uaddr, &sp, len);

      *usockaddr_len = len;

      return 0;
}


static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
            unsigned long arg)
{
      struct sock *sk = sock->sk;
      struct pppox_sock *po = pppox_sk(sk);
      int val;
      int err;

      switch (cmd) {
      case PPPIOCGMRU:
            err = -ENXIO;

            if (!(sk->sk_state & PPPOX_CONNECTED))
                  break;

            err = -EFAULT;
            if (put_user(po->pppoe_dev->mtu -
                       sizeof(struct pppoe_hdr) -
                       PPP_HDRLEN,
                       (int __user *) arg))
                  break;
            err = 0;
            break;

      case PPPIOCSMRU:
            err = -ENXIO;
            if (!(sk->sk_state & PPPOX_CONNECTED))
                  break;

            err = -EFAULT;
            if (get_user(val,(int __user *) arg))
                  break;

            if (val < (po->pppoe_dev->mtu
                     - sizeof(struct pppoe_hdr)
                     - PPP_HDRLEN))
                  err = 0;
            else
                  err = -EINVAL;
            break;

      case PPPIOCSFLAGS:
            err = -EFAULT;
            if (get_user(val, (int __user *) arg))
                  break;
            err = 0;
            break;

      case PPPOEIOCSFWD:
      {
            struct pppox_sock *relay_po;

            err = -EBUSY;
            if (sk->sk_state & (PPPOX_BOUND | PPPOX_ZOMBIE | PPPOX_DEAD))
                  break;

            err = -ENOTCONN;
            if (!(sk->sk_state & PPPOX_CONNECTED))
                  break;

            /* PPPoE address from the user specifies an outbound
               PPPoE address which frames are forwarded to */
            err = -EFAULT;
            if (copy_from_user(&po->pppoe_relay,
                           (void __user *)arg,
                           sizeof(struct sockaddr_pppox)))
                  break;

            err = -EINVAL;
            if (po->pppoe_relay.sa_family != AF_PPPOX ||
                po->pppoe_relay.sa_protocol!= PX_PROTO_OE)
                  break;

            /* Check that the socket referenced by the address
               actually exists. */
            relay_po = get_item_by_addr(&po->pppoe_relay);

            if (!relay_po)
                  break;

            sock_put(sk_pppox(relay_po));
            sk->sk_state |= PPPOX_RELAY;
            err = 0;
            break;
      }

      case PPPOEIOCDFWD:
            err = -EALREADY;
            if (!(sk->sk_state & PPPOX_RELAY))
                  break;

            sk->sk_state &= ~PPPOX_RELAY;
            err = 0;
            break;

      default:
            err = -ENOTTY;
      }

      return err;
}


static int pppoe_sendmsg(struct kiocb *iocb, struct socket *sock,
              struct msghdr *m, size_t total_len)
{
      struct sk_buff *skb;
      struct sock *sk = sock->sk;
      struct pppox_sock *po = pppox_sk(sk);
      int error;
      struct pppoe_hdr hdr;
      struct pppoe_hdr *ph;
      struct net_device *dev;
      char *start;

      lock_sock(sk);
      if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) {
            error = -ENOTCONN;
            goto end;
      }

      hdr.ver = 1;
      hdr.type = 1;
      hdr.code = 0;
      hdr.sid = po->num;

      dev = po->pppoe_dev;

      error = -EMSGSIZE;
      if (total_len > (dev->mtu + dev->hard_header_len))
            goto end;


      skb = sock_wmalloc(sk, total_len + dev->hard_header_len + 32,
                     0, GFP_KERNEL);
      if (!skb) {
            error = -ENOMEM;
            goto end;
      }

      /* Reserve space for headers. */
      skb_reserve(skb, dev->hard_header_len);
      skb_reset_network_header(skb);

      skb->dev = dev;

      skb->priority = sk->sk_priority;
      skb->protocol = __constant_htons(ETH_P_PPP_SES);

      ph = (struct pppoe_hdr *) skb_put(skb, total_len + sizeof(struct pppoe_hdr));
      start = (char *) &ph->tag[0];

      error = memcpy_fromiovec(start, m->msg_iov, total_len);

      if (error < 0) {
            kfree_skb(skb);
            goto end;
      }

      error = total_len;
      dev_hard_header(skb, dev, ETH_P_PPP_SES,
                  po->pppoe_pa.remote, NULL, total_len);

      memcpy(ph, &hdr, sizeof(struct pppoe_hdr));

      ph->length = htons(total_len);

      dev_queue_xmit(skb);

end:
      release_sock(sk);
      return error;
}


/************************************************************************
 *
 * xmit function for internal use.
 *
 ***********************************************************************/
static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
{
      struct pppox_sock *po = pppox_sk(sk);
      struct net_device *dev = po->pppoe_dev;
      struct pppoe_hdr *ph;
      int data_len = skb->len;

      if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
            goto abort;

      if (!dev)
            goto abort;

      /* Copy the data if there is no space for the header or if it's
       * read-only.
       */
      if (skb_cow_head(skb, sizeof(*ph) + dev->hard_header_len))
            goto abort;

      __skb_push(skb, sizeof(*ph));
      skb_reset_network_header(skb);

      ph = pppoe_hdr(skb);
      ph->ver     = 1;
      ph->type = 1;
      ph->code = 0;
      ph->sid     = po->num;
      ph->length = htons(data_len);

      skb->protocol = __constant_htons(ETH_P_PPP_SES);
      skb->dev = dev;

      dev_hard_header(skb, dev, ETH_P_PPP_SES,
                  po->pppoe_pa.remote, NULL, data_len);

      dev_queue_xmit(skb);

      return 1;

abort:
      kfree_skb(skb);
      return 1;
}


/************************************************************************
 *
 * xmit function called by generic PPP driver
 * sends PPP frame over PPPoE socket
 *
 ***********************************************************************/
static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
{
      struct sock *sk = (struct sock *) chan->private;
      return __pppoe_xmit(sk, skb);
}


static struct ppp_channel_ops pppoe_chan_ops = {
      .start_xmit = pppoe_xmit,
};

static int pppoe_recvmsg(struct kiocb *iocb, struct socket *sock,
              struct msghdr *m, size_t total_len, int flags)
{
      struct sock *sk = sock->sk;
      struct sk_buff *skb;
      int error = 0;

      if (sk->sk_state & PPPOX_BOUND) {
            error = -EIO;
            goto end;
      }

      skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
                        flags & MSG_DONTWAIT, &error);

      if (error < 0)
            goto end;

      m->msg_namelen = 0;

      if (skb) {
            struct pppoe_hdr *ph = pppoe_hdr(skb);
            const int len = ntohs(ph->length);

            error = memcpy_toiovec(m->msg_iov, (unsigned char *) &ph->tag[0], len);
            if (error == 0)
                  error = len;
      }

      kfree_skb(skb);
end:
      return error;
}

#ifdef CONFIG_PROC_FS
static int pppoe_seq_show(struct seq_file *seq, void *v)
{
      struct pppox_sock *po;
      char *dev_name;
      DECLARE_MAC_BUF(mac);

      if (v == SEQ_START_TOKEN) {
            seq_puts(seq, "Id       Address              Device\n");
            goto out;
      }

      po = v;
      dev_name = po->pppoe_pa.dev;

      seq_printf(seq, "%08X %s %8s\n",
               po->pppoe_pa.sid, print_mac(mac, po->pppoe_pa.remote), dev_name);
out:
      return 0;
}

static __inline__ struct pppox_sock *pppoe_get_idx(loff_t pos)
{
      struct pppox_sock *po;
      int i = 0;

      for (; i < PPPOE_HASH_SIZE; i++) {
            po = item_hash_table[i];
            while (po) {
                  if (!pos--)
                        goto out;
                  po = po->next;
            }
      }
out:
      return po;
}

static void *pppoe_seq_start(struct seq_file *seq, loff_t *pos)
{
      loff_t l = *pos;

      read_lock_bh(&pppoe_hash_lock);
      return l ? pppoe_get_idx(--l) : SEQ_START_TOKEN;
}

static void *pppoe_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
      struct pppox_sock *po;

      ++*pos;
      if (v == SEQ_START_TOKEN) {
            po = pppoe_get_idx(0);
            goto out;
      }
      po = v;
      if (po->next)
            po = po->next;
      else {
            int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);

            while (++hash < PPPOE_HASH_SIZE) {
                  po = item_hash_table[hash];
                  if (po)
                        break;
            }
      }
out:
      return po;
}

static void pppoe_seq_stop(struct seq_file *seq, void *v)
{
      read_unlock_bh(&pppoe_hash_lock);
}

static struct seq_operations pppoe_seq_ops = {
      .start            = pppoe_seq_start,
      .next       = pppoe_seq_next,
      .stop       = pppoe_seq_stop,
      .show       = pppoe_seq_show,
};

static int pppoe_seq_open(struct inode *inode, struct file *file)
{
      return seq_open(file, &pppoe_seq_ops);
}

static const struct file_operations pppoe_seq_fops = {
      .owner            = THIS_MODULE,
      .open       = pppoe_seq_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = seq_release,
};

static int __init pppoe_proc_init(void)
{
      struct proc_dir_entry *p;

      p = create_proc_entry("pppoe", S_IRUGO, init_net.proc_net);
      if (!p)
            return -ENOMEM;

      p->proc_fops = &pppoe_seq_fops;
      return 0;
}
#else /* CONFIG_PROC_FS */
static inline int pppoe_proc_init(void) { return 0; }
#endif /* CONFIG_PROC_FS */

static const struct proto_ops pppoe_ops = {
    .family       = AF_PPPOX,
    .owner        = THIS_MODULE,
    .release            = pppoe_release,
    .bind         = sock_no_bind,
    .connect            = pppoe_connect,
    .socketpair         = sock_no_socketpair,
    .accept       = sock_no_accept,
    .getname            = pppoe_getname,
    .poll         = datagram_poll,
    .listen       = sock_no_listen,
    .shutdown           = sock_no_shutdown,
    .setsockopt         = sock_no_setsockopt,
    .getsockopt         = sock_no_getsockopt,
    .sendmsg            = pppoe_sendmsg,
    .recvmsg            = pppoe_recvmsg,
    .mmap         = sock_no_mmap,
    .ioctl        = pppox_ioctl,
};

static struct pppox_proto pppoe_proto = {
    .create = pppoe_create,
    .ioctl  = pppoe_ioctl,
    .owner  = THIS_MODULE,
};


static int __init pppoe_init(void)
{
      int err = proto_register(&pppoe_sk_proto, 0);

      if (err)
            goto out;

      err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
      if (err)
            goto out_unregister_pppoe_proto;

      err = pppoe_proc_init();
      if (err)
            goto out_unregister_pppox_proto;

      dev_add_pack(&pppoes_ptype);
      dev_add_pack(&pppoed_ptype);
      register_netdevice_notifier(&pppoe_notifier);
out:
      return err;
out_unregister_pppox_proto:
      unregister_pppox_proto(PX_PROTO_OE);
out_unregister_pppoe_proto:
      proto_unregister(&pppoe_sk_proto);
      goto out;
}

static void __exit pppoe_exit(void)
{
      unregister_pppox_proto(PX_PROTO_OE);
      dev_remove_pack(&pppoes_ptype);
      dev_remove_pack(&pppoed_ptype);
      unregister_netdevice_notifier(&pppoe_notifier);
      remove_proc_entry("pppoe", init_net.proc_net);
      proto_unregister(&pppoe_sk_proto);
}

module_init(pppoe_init);
module_exit(pppoe_exit);

MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
MODULE_DESCRIPTION("PPP over Ethernet driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_PPPOX);

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