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af_wanpipe.c

/*****************************************************************************
* af_wanpipe.c    WANPIPE(tm) Secure Socket Layer.
*
* Author:   Nenad Corbic      <ncorbic@sangoma.com>
*
* Copyright:      (c) 2000 Sangoma Technologies Inc.
*
*           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.
* ============================================================================
* Due Credit:
*               Wanpipe socket layer is based on Packet and 
*               the X25 socket layers. The above sockets were 
*               used for the specific use of Sangoma Technoloiges 
*               API programs. 
*               Packet socket Authors: Ross Biro, Fred N. van Kempen and 
*                                      Alan Cox.
*               X25 socket Author: Jonathan Naylor.
* ============================================================================
* Mar 15, 2002  Arnaldo C. Melo  o Use wp_sk()->num, as it isnt anymore in sock
* Apr 25, 2000  Nenad Corbic     o Added the ability to send zero length packets.
* Mar 13, 2000  Nenad Corbic   o Added a tx buffer check via ioctl call.
* Mar 06, 2000  Nenad Corbic     o Fixed the corrupt sock lcn problem.
*                                  Server and client applicaton can run
*                                  simultaneously without conflicts.
* Feb 29, 2000  Nenad Corbic     o Added support for PVC protocols, such as
*                                  CHDLC, Frame Relay and HDLC API.
* Jan 17, 2000    Nenad Corbic       o Initial version, based on AF_PACKET socket.
*                            X25API support only. 
*
******************************************************************************/

#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/capability.h>
#include <linux/fcntl.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/poll.h>
#include <linux/wireless.h>
#include <linux/kmod.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/if_wanpipe.h>
#include <linux/pkt_sched.h>
#include <linux/tcp_states.h>
#include <linux/if_wanpipe_common.h>

#ifdef CONFIG_INET
#include <net/inet_common.h>
#endif

#define SLOW_BACKOFF 0.1*HZ
#define FAST_BACKOFF 0.01*HZ

//#define PRINT_DEBUG
#ifdef PRINT_DEBUG
      #define DBG_PRINTK(format, a...) printk(format, ## a)
#else
      #define DBG_PRINTK(format, a...)
#endif      


/* SECURE SOCKET IMPLEMENTATION 
 * 
 *   TRANSMIT:
 *
 *      When the user sends a packet via send() system call
 *      the wanpipe_sendmsg() function is executed.  
 *      
 *      Each packet is enqueud into sk->sk_write_queue transmit
 *      queue. When the packet is enqueued, a delayed transmit
 *      timer is triggerd which acts as a Bottom Half hander. 
 *
 *      wanpipe_delay_transmit() function (BH), dequeues packets
 *      from the sk->sk_write_queue transmit queue and sends it 
 *      to the deriver via dev->hard_start_xmit(skb, dev) function.  
 *      Note, this function is actual a function pointer of if_send()
 *      routine in the wanpipe driver.
 *
 *      X25API GUARANTEED DELIVERY:
 *
 *         In order to provide 100% guaranteed packet delivery, 
 *         an atomic 'packet_sent' counter is implemented.  Counter 
 *         is incremented for each packet enqueued 
 *         into sk->sk_write_queue.  Counter is decremented each
 *         time wanpipe_delayed_transmit() function successfuly 
 *         passes the packet to the driver. Before each send(), a poll
 *         routine checks the sock resources The maximum value of
 *         packet sent counter is 1, thus if one packet is queued, the
 *         application will block until that packet is passed to the
 *         driver.
 *
 *   RECEIVE:
 *
 *      Wanpipe device drivers call the socket bottom half
 *      function, wanpipe_rcv() to queue the incoming packets
 *      into an AF_WANPIPE socket queue.  Based on wanpipe_rcv()
 *      return code, the driver knows whether the packet was
 *      successfully queued.  If the socket queue is full, 
 *      protocol flow control is used by the driver, if any, 
 *      to slow down the traffic until the sock queue is free.
 *
 *      Every time a packet arrives into a socket queue the 
 *      socket wakes up processes which are waiting to receive
 *      data.
 *
 *      If the socket queue is full, the driver sets a block
 *      bit which signals the socket to kick the wanpipe driver
 *      bottom half hander when the socket queue is partialy
 *      empty. wanpipe_recvmsg() function performs this action.
 * 
 *      In case of x25api, packets will never be dropped, since
 *      flow control is available. 
 *      
 *      In case of streaming protocols like CHDLC, packets will 
 *      be dropped but the statistics will be generated. 
 */


/* The code below is used to test memory leaks. It prints out
 * a message every time kmalloc and kfree system calls get executed.
 * If the calls match there is no leak :)
 */

/***********FOR DEBUGGING PURPOSES*********************************************
#define KMEM_SAFETYZONE 8

static void * dbg_kmalloc(unsigned int size, int prio, int line) {
      void * v = kmalloc(size,prio);
      printk(KERN_INFO "line %d  kmalloc(%d,%d) = %p\n",line,size,prio,v);
      return v;
}
static void dbg_kfree(void * v, int line) {
      printk(KERN_INFO "line %d  kfree(%p)\n",line,v);
      kfree(v);
}

#define kmalloc(x,y) dbg_kmalloc(x,y,__LINE__)
#define kfree(x) dbg_kfree(x,__LINE__)
******************************************************************************/


/* List of all wanpipe sockets. */
HLIST_HEAD(wanpipe_sklist);
static DEFINE_RWLOCK(wanpipe_sklist_lock);

atomic_t wanpipe_socks_nr;
static unsigned long wanpipe_tx_critical;

#if 0
/* Private wanpipe socket structures. */
struct wanpipe_opt
{
      void   *mbox;           /* Mail box  */
      void   *card;           /* Card bouded to */
      struct net_device *dev; /* Bounded device */
      unsigned short lcn;     /* Binded LCN */
      unsigned char  svc;     /* 0=pvc, 1=svc */
      unsigned char  timer;   /* flag for delayed transmit*/      
      struct timer_list tx_timer;
      unsigned poll_cnt;
      unsigned char force;    /* Used to force sock release */
      atomic_t packet_sent;   
};
#endif

static int sk_count;
extern const struct proto_ops wanpipe_ops;
static unsigned long find_free_critical;

static void wanpipe_unlink_driver(struct sock *sk);
static void wanpipe_link_driver(struct net_device *dev, struct sock *sk);
static void wanpipe_wakeup_driver(struct sock *sk);
static int execute_command(struct sock *, unsigned char, unsigned int);
static int check_dev(struct net_device *dev, sdla_t *card);
struct net_device *wanpipe_find_free_dev(sdla_t *card);
static void wanpipe_unlink_card (struct sock *);
static int wanpipe_link_card (struct sock *);
static struct sock *wanpipe_make_new(struct sock *);
static struct sock *wanpipe_alloc_socket(void);
static inline int get_atomic_device(struct net_device *dev);
static int wanpipe_exec_cmd(struct sock *, int, unsigned int);
static int get_ioctl_cmd (struct sock *, void *);
static int set_ioctl_cmd (struct sock *, void *);
static void release_device(struct net_device *dev);
static void wanpipe_kill_sock_timer (unsigned long data);
static void wanpipe_kill_sock_irq (struct sock *);
static void wanpipe_kill_sock_accept (struct sock *);
static int wanpipe_do_bind(struct sock *sk, struct net_device *dev,
                     int protocol);
struct sock * get_newsk_from_skb (struct sk_buff *);
static int wanpipe_debug (struct sock *, void *);
static void wanpipe_delayed_transmit (unsigned long data);
static void release_driver(struct sock *);
static void start_cleanup_timer (struct sock *);
static void check_write_queue(struct sock *);
static int check_driver_busy (struct sock *);

/*============================================================
 * wanpipe_rcv
 *
 *    Wanpipe socket bottom half handler.  This function
 *      is called by the WANPIPE device drivers to queue a
 *      incoming packet into the socket receive queue. 
 *      Once the packet is queued, all processes waiting to 
 *      read are woken up.
 *
 *      During socket bind, this function is bounded into
 *      WANPIPE driver private.
 *===========================================================*/

static int wanpipe_rcv(struct sk_buff *skb, struct net_device *dev,
                   struct sock *sk)
{
      struct wan_sockaddr_ll *sll = (struct wan_sockaddr_ll*)skb->cb;
      wanpipe_common_t *chan = dev->priv;
      /*
       *    When we registered the protocol we saved the socket in the data
       *    field for just this event.
       */

      skb->dev = dev;

      sll->sll_family = AF_WANPIPE;
      sll->sll_hatype = dev->type;
      sll->sll_protocol = skb->protocol;
      sll->sll_pkttype = skb->pkt_type;
      sll->sll_ifindex = dev->ifindex;
      sll->sll_halen = 0;

      if (dev->hard_header_parse)
            sll->sll_halen = dev->hard_header_parse(skb, sll->sll_addr);

      /* 
       * WAN_PACKET_DATA : Data which should be passed up the receive queue.
         * WAN_PACKET_ASYC : Asynchronous data like place call, which should
         *                   be passed up the listening sock.
         * WAN_PACKET_ERR  : Asynchronous data like clear call or restart 
         *                   which should go into an error queue.
         */
      switch (skb->pkt_type){

            case WAN_PACKET_DATA:
                  if (sock_queue_rcv_skb(sk,skb)<0){
                        return -ENOMEM;
                  }
                  break;
            case WAN_PACKET_CMD:
                  sk->sk_state = chan->state;
                  /* Bug fix: update Mar6. 
                         * Do not set the sock lcn number here, since
                   * cmd is not guaranteed to be executed on the
                         * board, thus Lcn could be wrong */
                  sk->sk_data_ready(sk, skb->len);
                  kfree_skb(skb);
                  break;
            case WAN_PACKET_ERR:
                  sk->sk_state = chan->state;
                  if (sock_queue_err_skb(sk,skb)<0){
                        return -ENOMEM;
                  }
                  break;
            default:
                  printk(KERN_INFO "wansock: BH Illegal Packet Type Dropping\n");
                  kfree_skb(skb); 
                  break;
      }

//??????????????????????
//    if (sk->sk_state == WANSOCK_DISCONNECTED){
//          if (sk->sk_zapped) {
//                //printk(KERN_INFO "wansock: Disconnected, killing early\n");
//                wanpipe_unlink_driver(sk);
//                sk->sk_bound_dev_if = 0;
//          }
//    }

      return 0;
}

/*============================================================
 * wanpipe_listen_rcv
 *
 *    Wanpipe LISTEN socket bottom half handler.  This function
 *      is called by the WANPIPE device drivers to queue an
 *      incoming call into the socket listening queue. 
 *      Once the packet is queued, the waiting accept() process 
 *      is woken up.
 *
 *      During socket bind, this function is bounded into
 *      WANPIPE driver private. 
 * 
 *      IMPORTANT NOTE:
 *          The accept call() is waiting for an skb packet
 *          which contains a pointer to a device structure.
 *
 *          When we do a bind to a device structre, we 
 *          bind a newly created socket into "chan->sk".  Thus, 
 *          when accept receives the skb packet, it will know 
 *          from which dev it came form, and in turn it will know
 *          the address of the new sock.
 *
 *    NOTE: This function gets called from driver ISR.
 *===========================================================*/

static int wanpipe_listen_rcv (struct sk_buff *skb,  struct sock *sk)
{
      wanpipe_opt *wp = wp_sk(sk), *newwp;
      struct wan_sockaddr_ll *sll = (struct wan_sockaddr_ll*)skb->cb;
      struct sock *newsk;
      struct net_device *dev; 
      sdla_t *card;
      mbox_cmd_t *mbox_ptr;
      wanpipe_common_t *chan;

      /* Find a free device, if none found, all svc's are busy 
         */

      card = (sdla_t*)wp->card;
      if (!card){
            printk(KERN_INFO "wansock: LISTEN ERROR, No Card\n");
            return -ENODEV;
      }
      
      dev = wanpipe_find_free_dev(card);
      if (!dev){
            printk(KERN_INFO "wansock: LISTEN ERROR, No Free Device\n");
            return -ENODEV;
      }

      chan=dev->priv;   
      chan->state = WANSOCK_CONNECTING;

      /* Allocate a new sock, which accept will bind
         * and pass up to the user 
       */
      if ((newsk = wanpipe_make_new(sk)) == NULL){
            release_device(dev);
            return -ENOMEM;
      }


      /* Initialize the new sock structure 
       */
      newsk->sk_bound_dev_if = dev->ifindex;
      newwp = wp_sk(newsk);
      newwp->card = wp->card;

      /* Insert the sock into the main wanpipe
         * sock list.
         */
      atomic_inc(&wanpipe_socks_nr);

      /* Allocate and fill in the new Mail Box. Then
         * bind the mail box to the sock. It will be 
         * used by the ioctl call to read call information
         * and to execute commands. 
         */ 
      if ((mbox_ptr = kzalloc(sizeof(mbox_cmd_t), GFP_ATOMIC)) == NULL) {
            wanpipe_kill_sock_irq (newsk);
            release_device(dev);          
            return -ENOMEM;
      }
      memcpy(mbox_ptr,skb->data,skb->len);

      /* Register the lcn on which incoming call came
         * from. Thus, if we have to clear it, we know
         * which lcn to clear
       */ 

      newwp->lcn = mbox_ptr->cmd.lcn;
      newwp->mbox = (void *)mbox_ptr;

      DBG_PRINTK(KERN_INFO "NEWSOCK : Device %s, bind to lcn %i\n",
                  dev->name,mbox_ptr->cmd.lcn);

      chan->lcn = mbox_ptr->cmd.lcn;
      card->u.x.svc_to_dev_map[(chan->lcn%MAX_X25_LCN)] = dev;

      sock_reset_flag(newsk, SOCK_ZAPPED);
      newwp->num = htons(X25_PROT);

      if (wanpipe_do_bind(newsk, dev, newwp->num)) {
            wanpipe_kill_sock_irq (newsk);
            release_device(dev);
            return -EINVAL;
      }
      newsk->sk_state = WANSOCK_CONNECTING;


      /* Fill in the standard sock address info */

      sll->sll_family = AF_WANPIPE;
      sll->sll_hatype = dev->type;
      sll->sll_protocol = skb->protocol;
      sll->sll_pkttype = skb->pkt_type;
      sll->sll_ifindex = dev->ifindex;
      sll->sll_halen = 0;

      skb->dev = dev;
      sk->sk_ack_backlog++;

      /* We must do this manually, since the sock_queue_rcv_skb()
       * function sets the skb->dev to NULL.  However, we use
       * the dev field in the accept function.*/ 
      if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >= 
          (unsigned)sk->sk_rcvbuf) {

            wanpipe_unlink_driver(newsk);
            wanpipe_kill_sock_irq (newsk);
            --sk->sk_ack_backlog;
            return -ENOMEM;
      }     

      skb_set_owner_r(skb, sk);
      skb_queue_tail(&sk->sk_receive_queue, skb);
      sk->sk_data_ready(sk, skb->len);
      
      return 0;
}



/*============================================================
 * wanpipe_make_new
 *
 *    Create a new sock, and allocate a wanpipe private
 *      structure to it. Also, copy the important data
 *      from the original sock to the new sock.
 *
 *      This function is used by wanpipe_listen_rcv() listen
 *      bottom half handler.  A copy of the listening sock
 *      is created using this function.
 *
 *===========================================================*/

static struct sock *wanpipe_make_new(struct sock *osk)
{
      struct sock *sk;

      if (osk->sk_type != SOCK_RAW)
            return NULL;

      if ((sk = wanpipe_alloc_socket()) == NULL)
            return NULL;

      sk->sk_type = osk->sk_type;
      sk->sk_socket     = osk->sk_socket;
      sk->sk_priority   = osk->sk_priority;
      sk->sk_protocol   = osk->sk_protocol;
      wp_sk(sk)->num    = wp_sk(osk)->num;
      sk->sk_rcvbuf     = osk->sk_rcvbuf;
      sk->sk_sndbuf     = osk->sk_sndbuf;
      sk->sk_state      = WANSOCK_CONNECTING;
      sk->sk_sleep      = osk->sk_sleep;

      if (sock_flag(osk, SOCK_DBG))
            sock_set_flag(sk, SOCK_DBG);

      return sk;
}

/* 
 * FIXME: wanpipe_opt has to include a sock in its definition and stop using
 * sk_protinfo, but this code is not even compilable now, so lets leave it for
 * later.
 */
static struct proto wanpipe_proto = {
      .name   = "WANPIPE",
      .owner        = THIS_MODULE,
      .obj_size = sizeof(struct sock),
};

/*============================================================
 * wanpipe_make_new
 *
 *    Allocate memory for the a new sock, and sock
 *      private data.  
 *    
 *    Increment the module use count.
 *          
 *      This function is used by wanpipe_create() and 
 *      wanpipe_make_new() functions. 
 *
 *===========================================================*/

static struct sock *wanpipe_alloc_socket(void)
{
      struct sock *sk;
      struct wanpipe_opt *wan_opt;

      if ((sk = sk_alloc(PF_WANPIPE, GFP_ATOMIC, &wanpipe_proto, 1)) == NULL)
            return NULL;

      if ((wan_opt = kzalloc(sizeof(struct wanpipe_opt), GFP_ATOMIC)) == NULL) {
            sk_free(sk);
            return NULL;
      }

      wp_sk(sk) = wan_opt;

      /* Use timer to send data to the driver. This will act
         * as a BH handler for sendmsg functions */
      init_timer(&wan_opt->tx_timer);
      wan_opt->tx_timer.data     = (unsigned long)sk;
      wan_opt->tx_timer.function = wanpipe_delayed_transmit;

      sock_init_data(NULL, sk);
      return sk;
}


/*============================================================
 * wanpipe_sendmsg
 *
 *    This function implements a sendto() system call,
 *      for AF_WANPIPE socket family. 
 *      During socket bind() sk->sk_bound_dev_if is initialized
 *      to a correct network device. This number is used
 *      to find a network device to which the packet should
 *      be passed to.
 *
 *      Each packet is queued into sk->sk_write_queue and 
 *      delayed transmit bottom half handler is marked for 
 *      execution.
 *
 *      A socket must be in WANSOCK_CONNECTED state before
 *      a packet is queued into sk->sk_write_queue.
 *===========================================================*/

static int wanpipe_sendmsg(struct kiocb *iocb, struct socket *sock,
                     struct msghdr *msg, int len)
{
      wanpipe_opt *wp;
      struct sock *sk = sock->sk;
      struct wan_sockaddr_ll *saddr=(struct wan_sockaddr_ll *)msg->msg_name;
      struct sk_buff *skb;
      struct net_device *dev;
      unsigned short proto;
      unsigned char *addr;
      int ifindex, err, reserve = 0;

      
      if (!sock_flag(sk, SOCK_ZAPPED))
            return -ENETDOWN;

      if (sk->sk_state != WANSOCK_CONNECTED)
            return -ENOTCONN; 

      if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT)) 
            return(-EINVAL);

      /* it was <=, now one can send
         * zero length packets */
      if (len < sizeof(x25api_hdr_t))
            return -EINVAL;

      wp = wp_sk(sk);

      if (saddr == NULL) {
            ifindex     = sk->sk_bound_dev_if;
            proto = wp->num;
            addr  = NULL;

      }else{
            if (msg->msg_namelen < sizeof(struct wan_sockaddr_ll)){ 
                  return -EINVAL;
            }

            ifindex = sk->sk_bound_dev_if;
            proto = saddr->sll_protocol;
            addr  = saddr->sll_addr;
      }

      dev = dev_get_by_index(ifindex);
      if (dev == NULL){
            printk(KERN_INFO "wansock: Send failed, dev index: %i\n",ifindex);
            return -ENXIO;
      }
      dev_put(dev);
      
      if (sock->type == SOCK_RAW)
            reserve = dev->hard_header_len;

      if (len > dev->mtu+reserve){
            return -EMSGSIZE;
      }

      skb = sock_alloc_send_skb(sk, len + LL_RESERVED_SPACE(dev),
                        msg->msg_flags & MSG_DONTWAIT, &err);

      if (skb==NULL){
            goto out_unlock;
      }
            
      skb_reserve(skb, LL_RESERVED_SPACE(dev));
      skb->nh.raw = skb->data;

      /* Returns -EFAULT on error */
      err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
      if (err){
            goto out_free;
      }

      if (dev->hard_header) {
            int res;
            err = -EINVAL;
            res = dev->hard_header(skb, dev, ntohs(proto), addr, NULL, len);
            if (res<0){
                  goto out_free;
            }
      }

      skb->protocol = proto;
      skb->dev = dev;
      skb->priority = sk->sk_priority;
      skb->pkt_type = WAN_PACKET_DATA;

      err = -ENETDOWN;
      if (!(dev->flags & IFF_UP))
            goto out_free;

      if (atomic_read(&sk->sk_wmem_alloc) + skb->truesize >
          (unsigned int)sk->sk_sndbuf){
            kfree_skb(skb);
            return -ENOBUFS;
      }

      skb_queue_tail(&sk->sk_write_queue,skb);
      atomic_inc(&wp->packet_sent);

      if (!(test_and_set_bit(0, &wp->timer)))
            mod_timer(&wp->tx_timer, jiffies + 1);
      
      return(len);

out_free:
      kfree_skb(skb);
out_unlock:
      return err;
}

/*============================================================
 * wanpipe_delayed_tarnsmit
 *
 *    Transmit bottom half handler. It dequeues packets
 *      from sk->sk_write_queue and passes them to the 
 *      driver.  If the driver is busy, the packet is 
 *      re-enqueued.  
 *
 *      Packet Sent counter is decremented on successful
 *      transmission. 
 *===========================================================*/


static void wanpipe_delayed_transmit (unsigned long data)
{
      struct sock *sk=(struct sock *)data;
      struct sk_buff *skb;
      wanpipe_opt *wp = wp_sk(sk);
      struct net_device *dev = wp->dev;
      sdla_t *card = (sdla_t*)wp->card;

      if (!card || !dev){
            clear_bit(0, &wp->timer);
            DBG_PRINTK(KERN_INFO "wansock: Transmit delay, no dev or card\n");
            return;
      }
      
      if (sk->sk_state != WANSOCK_CONNECTED || !sock_flag(sk, SOCK_ZAPPED)) {
            clear_bit(0, &wp->timer);
            DBG_PRINTK(KERN_INFO "wansock: Tx Timer, State not CONNECTED\n");
            return;
      }
      
      /* If driver is executing command, we must offload
         * the board by not sending data. Otherwise a 
         * pending command will never get a free buffer
         * to execute */      
      if (atomic_read(&card->u.x.command_busy)){
            wp->tx_timer.expires = jiffies + SLOW_BACKOFF;
            add_timer(&wp->tx_timer);
            DBG_PRINTK(KERN_INFO "wansock: Tx Timer, command bys BACKOFF\n");
            return;
      }

      
      if (test_and_set_bit(0,&wanpipe_tx_critical)){
            printk(KERN_INFO "WanSock: Tx timer critical %s\n",dev->name);
            wp->tx_timer.expires = jiffies + SLOW_BACKOFF;
            add_timer(&wp->tx_timer);
            return;
      }     
      
      /* Check for a packet in the fifo and send */
      if ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL){

            if (dev->hard_start_xmit(skb, dev) != 0){             

                  /* Driver failed to transmit, re-enqueue
                         * the packet and retry again later */
                  skb_queue_head(&sk->sk_write_queue,skb);
                  clear_bit(0,&wanpipe_tx_critical);
                  return;
            }else{

                  /* Packet Sent successful. Check for more packets
                         * if more packets, re-trigger the transmit routine 
                         * other wise exit
                         */
                  atomic_dec(&wp->packet_sent);

                  if (skb_peek(&sk->sk_write_queue) == NULL) {
                        /* If there is nothing to send, kick
                         * the poll routine, which will trigger
                         * the application to send more data */
                        sk->sk_data_ready(sk, 0);
                        clear_bit(0, &wp->timer);
                  }else{
                        /* Reschedule as fast as possible */
                        wp->tx_timer.expires = jiffies + 1;
                        add_timer(&wp->tx_timer);
                  }
            }
      }
      clear_bit(0,&wanpipe_tx_critical);
}

/*============================================================
 * execute_command 
 *
 *    Execute x25api commands.  The atomic variable
 *      chan->command is used to indicate to the driver that
 *      command is pending for execution.  The acutal command
 *      structure is placed into a sock mbox structure 
 *      (wp_sk(sk)->mbox).
 *
 *      The sock private structure, mbox is
 *      used as shared memory between sock and the driver.
 *      Driver uses the sock mbox to execute the command
 *      and return the result.  
 *
 *      For all command except PLACE CALL, the function
 *      waits for the result.  PLACE CALL can be ether
 *      blocking or nonblocking. The user sets this option
 *      via ioctl call.
 *===========================================================*/


static int execute_command(struct sock *sk,  unsigned char cmd, unsigned int flags)
{
      wanpipe_opt *wp = wp_sk(sk);
      struct net_device *dev;
      wanpipe_common_t *chan=NULL;
      int err=0;
      DECLARE_WAITQUEUE(wait, current);
      
      dev = dev_get_by_index(sk->sk_bound_dev_if);
      if (dev == NULL){
            printk(KERN_INFO "wansock: Exec failed no dev %i\n",
                  sk->sk_bound_dev_if);
            return -ENODEV;
      }
      dev_put(dev);

      if ((chan=dev->priv) == NULL){
            printk(KERN_INFO "wansock: Exec cmd failed no priv area\n");
            return -ENODEV;
      }

      if (atomic_read(&chan->command)){
            printk(KERN_INFO "wansock: ERROR: Command already running %x, %s\n",
                  atomic_read(&chan->command),dev->name);
            return -EINVAL;
      }

      if (!wp->mbox) {
            printk(KERN_INFO "wansock: In execute without MBOX\n");
            return -EINVAL;
      }

      ((mbox_cmd_t*)wp->mbox)->cmd.command = cmd;     
      ((mbox_cmd_t*)wp->mbox)->cmd.lcn     = wp->lcn;
      ((mbox_cmd_t*)wp->mbox)->cmd.result  = 0x7F;


      if (flags & O_NONBLOCK){
            cmd |= 0x80;
            atomic_set(&chan->command, cmd);
      }else{
            atomic_set(&chan->command, cmd);
      }

      add_wait_queue(sk->sk_sleep,&wait);
      current->state = TASK_INTERRUPTIBLE;
      for (;;){
            if (((mbox_cmd_t*)wp->mbox)->cmd.result != 0x7F) {
                  err = 0;
                  break;
            }
            if (signal_pending(current)) {
                  err = -ERESTARTSYS;
                  break;
            }
            schedule();
      }
      current->state = TASK_RUNNING;
      remove_wait_queue(sk->sk_sleep,&wait);
      
      return err;
}

/*============================================================
 * wanpipe_destroy_timer 
 *
 *    Used by wanpipe_release, to delay release of
 *      the socket.
 *===========================================================*/

static void wanpipe_destroy_timer(unsigned long data)
{
      struct sock *sk=(struct sock *)data;
      wanpipe_opt *wp = wp_sk(sk);

      if ((!atomic_read(&sk->sk_wmem_alloc) &&
           !atomic_read(&sk->sk_rmem_alloc)) ||
          (++wp->force == 5)) {

            if (atomic_read(&sk->sk_wmem_alloc) ||
                atomic_read(&sk->sk_rmem_alloc))
                  printk(KERN_INFO "wansock: Warning, Packet Discarded due to sock shutdown!\n");

            kfree(wp);
            wp_sk(sk) = NULL;
            
            if (atomic_read(&sk->sk_refcnt) != 1) {
                  atomic_set(&sk->sk_refcnt, 1);
                  DBG_PRINTK(KERN_INFO "wansock: Error, wrong reference count: %i ! :delay.\n",
                              atomic_read(&sk->sk_refcnt));
            }
            sock_put(sk);
            atomic_dec(&wanpipe_socks_nr);
            return;
      }

      sk->sk_timer.expires = jiffies + 5 * HZ;
      add_timer(&sk->sk_timer);
      printk(KERN_INFO "wansock: packet sk destroy delayed\n");
}

/*============================================================
 * wanpipe_unlink_driver
 *
 *    When the socket is released, this function is 
 *      used to remove links that bind the sock and the
 *      driver together.  
 *===========================================================*/
static void wanpipe_unlink_driver (struct sock *sk)
{
      struct net_device *dev;
      wanpipe_common_t *chan=NULL;

      sock_reset_flag(sk, SOCK_ZAPPED);
      sk->sk_state = WANSOCK_DISCONNECTED;
      wp_sk(sk)->dev = NULL;

      dev = dev_get_by_index(sk->sk_bound_dev_if);
      if (!dev){
            printk(KERN_INFO "wansock: No dev on release\n");
            return;
      }                 
      dev_put(dev);

      if ((chan = dev->priv) == NULL){
            printk(KERN_INFO "wansock: No Priv Area on release\n");
            return;
      }

      set_bit(0,&chan->common_critical);
      chan->sk=NULL;
      chan->func=NULL;
      chan->mbox=NULL;
      chan->tx_timer=NULL;
      clear_bit(0,&chan->common_critical);
      release_device(dev);
      
      return;
}

/*============================================================
 * wanpipe_link_driver
 *
 *    Upon successful bind(), sock is linked to a driver
 *      by binding in the wanpipe_rcv() bottom half handler
 *      to the driver function pointer, as well as sock and
 *      sock mailbox addresses.  This way driver can pass
 *      data up the socket.
 *===========================================================*/

static void wanpipe_link_driver(struct net_device *dev, struct sock *sk)
{
      wanpipe_opt *wp = wp_sk(sk);
      wanpipe_common_t *chan = dev->priv;
      if (!chan)
            return;
      set_bit(0,&chan->common_critical);
      chan->sk=sk;
      chan->func=wanpipe_rcv;
      chan->mbox = wp->mbox;
      chan->tx_timer = &wp->tx_timer;
      wp->dev = dev;
      sock_set_flag(sk, SOCK_ZAPPED);
      clear_bit(0,&chan->common_critical);
}


/*============================================================
 * release_device
 *
 *    During sock release, clear a critical bit, which 
 *      marks the device a being taken.
 *===========================================================*/


static void release_device(struct net_device *dev)
{
      wanpipe_common_t *chan=dev->priv;
      clear_bit(0,(void*)&chan->rw_bind);
}

/*============================================================
 * wanpipe_release
 *
 *    Close a PACKET socket. This is fairly simple. We 
 *      immediately go to 'closed' state and remove our 
 *      protocol entry in the device list.
 *===========================================================*/

static int wanpipe_release(struct socket *sock)
{
      wanpipe_opt *wp;
      struct sock *sk = sock->sk;
      
      if (!sk)
            return 0;

      wp = wp_sk(sk);
      check_write_queue(sk);

      /* Kill the tx timer, if we don't kill it now, the timer
         * will run after we kill the sock.  Timer code will 
         * try to access the sock which has been killed and cause
         * kernel panic */

      del_timer(&wp->tx_timer);

      /*
       *    Unhook packet receive handler.
       */

      if (wp->num == htons(X25_PROT) &&
          sk->sk_state != WANSOCK_DISCONNECTED && sock_flag(sk, SOCK_ZAPPED)) {
            struct net_device *dev = dev_get_by_index(sk->sk_bound_dev_if);
            wanpipe_common_t *chan;
            if (dev){
                  chan=dev->priv;
                  atomic_set(&chan->disconnect,1);
                  DBG_PRINTK(KERN_INFO "wansock: Sending Clear Indication %i\n",
                              sk->sk_state);
                  dev_put(dev);
            }     
      }

      set_bit(1,&wanpipe_tx_critical);
      write_lock(&wanpipe_sklist_lock);
      sk_del_node_init(sk);
      write_unlock(&wanpipe_sklist_lock);
      clear_bit(1,&wanpipe_tx_critical);


      
      release_driver(sk);

      
      /*
       *    Now the socket is dead. No more input will appear.
       */

      sk->sk_state_change(sk);      /* It is useless. Just for sanity. */

      sock->sk = NULL;
      sk->sk_socket = NULL;
      sock_set_flag(sk, SOCK_DEAD);

      /* Purge queues */
      skb_queue_purge(&sk->sk_receive_queue);
      skb_queue_purge(&sk->sk_write_queue);
      skb_queue_purge(&sk->sk_error_queue);

      if (atomic_read(&sk->sk_rmem_alloc) ||
          atomic_read(&sk->sk_wmem_alloc)) {
            del_timer(&sk->sk_timer);
            printk(KERN_INFO "wansock: Killing in Timer R %i , W %i\n",
                  atomic_read(&sk->sk_rmem_alloc),
                  atomic_read(&sk->sk_wmem_alloc));
            sk->sk_timer.data = (unsigned long)sk;
            sk->sk_timer.expires    = jiffies + HZ;
            sk->sk_timer.function   = wanpipe_destroy_timer;
            add_timer(&sk->sk_timer);
            return 0;
      }

      kfree(wp);
      wp_sk(sk) = NULL;

      if (atomic_read(&sk->sk_refcnt) != 1) {
            DBG_PRINTK(KERN_INFO "wansock: Error, wrong reference count: %i !:release.\n",
                              atomic_read(&sk->sk_refcnt));
            atomic_set(&sk->sk_refcnt, 1);
      }
      sock_put(sk);
      atomic_dec(&wanpipe_socks_nr);
      return 0;
}

/*============================================================
 * check_write_queue
 *
 *    During sock shutdown, if the sock state is 
 *      WANSOCK_CONNECTED and there is transmit data 
 *      pending. Wait until data is released 
 *      before proceeding.
 *===========================================================*/

static void check_write_queue(struct sock *sk)
{

      if (sk->sk_state != WANSOCK_CONNECTED)
            return;

      if (!atomic_read(&sk->sk_wmem_alloc))
            return;

      printk(KERN_INFO "wansock: MAJOR ERROR, Data lost on sock release !!!\n");

}

/*============================================================
 * release_driver
 *
 *    This function is called during sock shutdown, to 
 *      release any resources and links that bind the sock
 *      to the driver.  It also changes the state of the
 *      sock to WANSOCK_DISCONNECTED
 *===========================================================*/

static void release_driver(struct sock *sk)
{
      wanpipe_opt *wp;
      struct sk_buff *skb=NULL;
      struct sock *deadsk=NULL;

      if (sk->sk_state == WANSOCK_LISTEN ||
          sk->sk_state == WANSOCK_BIND_LISTEN) {
            while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
                  if ((deadsk = get_newsk_from_skb(skb))){
                        DBG_PRINTK (KERN_INFO "wansock: RELEASE: FOUND DEAD SOCK\n");
                        sock_set_flag(deadsk, SOCK_DEAD);
                        start_cleanup_timer(deadsk);
                  }
                  kfree_skb(skb);
            }
            if (sock_flag(sk, SOCK_ZAPPED))
                  wanpipe_unlink_card(sk);
      }else{
            if (sock_flag(sk, SOCK_ZAPPED))
                  wanpipe_unlink_driver(sk);
      }
      sk->sk_state          = WANSOCK_DISCONNECTED;
      sk->sk_bound_dev_if = 0;
      sock_reset_flag(sk, SOCK_ZAPPED);
      wp = wp_sk(sk);

      if (wp) {
            kfree(wp->mbox);
            wp->mbox = NULL;
      }
}

/*============================================================
 *  start_cleanup_timer
 *
 *    If new incoming call's are pending but the socket
 *      is being released, start the timer which will 
 *      envoke the kill routines for pending socks.
 *===========================================================*/


static void start_cleanup_timer (struct sock *sk)
{
      del_timer(&sk->sk_timer);
      sk->sk_timer.data = (unsigned long)sk;
      sk->sk_timer.expires    = jiffies + HZ;
      sk->sk_timer.function   = wanpipe_kill_sock_timer;
      add_timer(&sk->sk_timer);
}


/*============================================================
 *  wanpipe_kill_sock
 *
 *    This is a function which performs actual killing
 *      of the sock.  It releases socket resources,
 *      and unlinks the sock from the driver. 
 *===========================================================*/

static void wanpipe_kill_sock_timer (unsigned long data)
{

      struct sock *sk = (struct sock *)data;
      struct sock **skp;

      if (!sk)
            return;

      /* This function can be called from interrupt. We must use
       * appropriate locks */
      
      if (test_bit(1,&wanpipe_tx_critical)){
            sk->sk_timer.expires = jiffies + 10;
            add_timer(&sk->sk_timer);
            return;
      }
      
      write_lock(&wanpipe_sklist_lock);
      sk_del_node_init(sk);
      write_unlock(&wanpipe_sklist_lock);


      if (wp_sk(sk)->num == htons(X25_PROT) &&
          sk->sk_state != WANSOCK_DISCONNECTED) {
            struct net_device *dev = dev_get_by_index(sk->sk_bound_dev_if);
            wanpipe_common_t *chan;
            if (dev){
                  chan=dev->priv;
                  atomic_set(&chan->disconnect,1);
                  dev_put(dev);
            }     
      }

      release_driver(sk);

      sk->sk_socket = NULL;

      /* Purge queues */
      skb_queue_purge(&sk->sk_receive_queue);
      skb_queue_purge(&sk->sk_write_queue);
      skb_queue_purge(&sk->sk_error_queue);
      
      if (atomic_read(&sk->sk_rmem_alloc) ||
          atomic_read(&sk->sk_wmem_alloc)) {
            del_timer(&sk->sk_timer);
            printk(KERN_INFO "wansock: Killing SOCK in Timer\n");
            sk->sk_timer.data = (unsigned long)sk;
            sk->sk_timer.expires    = jiffies + HZ;
            sk->sk_timer.function   = wanpipe_destroy_timer;
            add_timer(&sk->sk_timer);
            return;
      }

      kfree(wp_sk(sk));
      wp_sk(sk) = NULL;

      if (atomic_read(&sk->sk_refcnt) != 1) {
            atomic_set(&sk->sk_refcnt, 1);
            DBG_PRINTK(KERN_INFO "wansock: Error, wrong reference count: %i ! :timer.\n",
                              atomic_read(&sk->sk_refcnt));
      }
      sock_put(sk);
      atomic_dec(&wanpipe_socks_nr);
      return;
}

static void wanpipe_kill_sock_accept (struct sock *sk)
{

      struct sock **skp;

      if (!sk)
            return;

      /* This function can be called from interrupt. We must use
       * appropriate locks */
      
      write_lock(&wanpipe_sklist_lock);
      sk_del_node_init(sk);
      write_unlock(&wanpipe_sklist_lock);

      sk->sk_socket = NULL;


      kfree(wp_sk(sk));
      wp_sk(sk) = NULL;

      if (atomic_read(&sk->sk_refcnt) != 1) {
            atomic_set(&sk->sk_refcnt, 1);
            DBG_PRINTK(KERN_INFO "wansock: Error, wrong reference count: %i ! :timer.\n",
                              atomic_read(&sk->sk_refcnt));
      }
      sock_put(sk);
      atomic_dec(&wanpipe_socks_nr);
      return;
}


static void wanpipe_kill_sock_irq (struct sock *sk)
{

      if (!sk)
            return;

      sk->sk_socket = NULL;

      kfree(wp_sk(sk));
      wp_sk(sk) = NULL;

      if (atomic_read(&sk->sk_refcnt) != 1) {
            atomic_set(&sk->sk_refcnt, 1);
            DBG_PRINTK(KERN_INFO "wansock: Error, wrong reference count: %i !:listen.\n",
                              atomic_read(&sk->sk_refcnt));
      }
      sock_put(sk);
      atomic_dec(&wanpipe_socks_nr);
}


/*============================================================
 *  wanpipe_do_bind
 *
 *    Bottom half of the binding system call.
 *      Once the wanpipe_bind() function checks  the
 *      legality of the call, this function binds the
 *      sock to the driver.
 *===========================================================*/

static int wanpipe_do_bind(struct sock *sk, struct net_device *dev,
                     int protocol)
{
      wanpipe_opt *wp = wp_sk(sk);
      wanpipe_common_t *chan=NULL;
      int err=0;

      if (sock_flag(sk, SOCK_ZAPPED)) {
            err = -EALREADY;
            goto bind_unlock_exit;
      }

      wp->num = protocol;

      if (protocol == 0){
            release_device(dev);
            err = -EINVAL;
            goto bind_unlock_exit;
      }

      if (dev) {
            if (dev->flags&IFF_UP) {
                  chan=dev->priv;
                  sk->sk_state = chan->state;

                  if (wp->num == htons(X25_PROT) && 
                      sk->sk_state != WANSOCK_DISCONNECTED && 
                      sk->sk_state != WANSOCK_CONNECTING) {
                        DBG_PRINTK(KERN_INFO 
                              "wansock: Binding to Device not DISCONNECTED %i\n",
                                    sk->sk_state);
                        release_device(dev);
                        err = -EAGAIN;
                        goto bind_unlock_exit;
                  }

                  wanpipe_link_driver(dev,sk);
                  sk->sk_bound_dev_if = dev->ifindex;

                  /* X25 Specific option */
                  if (wp->num == htons(X25_PROT))
                        wp_sk(sk)->svc = chan->svc;

            } else {
                  sk->sk_err = ENETDOWN;
                  sk->sk_error_report(sk);
                  release_device(dev);
                  err = -EINVAL;
            }
      } else {
            err = -ENODEV;
      }
bind_unlock_exit:
      /* FIXME where is this lock */

      return err;
}

/*============================================================
 *  wanpipe_bind
 *
 *      BIND() System call, which is bound to the AF_WANPIPE
 *      operations structure.  It checks for correct wanpipe
 *      card name, and cross references interface names with
 *      the card names.  Thus, interface name must belong to
 *      the actual card.
 *===========================================================*/


static int wanpipe_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
      struct wan_sockaddr_ll *sll = (struct wan_sockaddr_ll*)uaddr;
      struct sock *sk=sock->sk;
      wanpipe_opt *wp = wp_sk(sk);
      struct net_device *dev = NULL;
      sdla_t *card=NULL;
      char name[15];

      /*
       *    Check legality
       */
       
      if (addr_len < sizeof(struct wan_sockaddr_ll)){
            printk(KERN_INFO "wansock: Address length error\n");
            return -EINVAL;
      }
      if (sll->sll_family != AF_WANPIPE){
            printk(KERN_INFO "wansock: Illegal family name specified.\n");
            return -EINVAL;
      }

      card = wanpipe_find_card (sll->sll_card);
      if (!card){
            printk(KERN_INFO "wansock: Wanpipe card not found: %s\n",sll->sll_card);
            return -ENODEV;
      }else{
            wp_sk(sk)->card = (void *)card;
      }

      if (!strcmp(sll->sll_device,"svc_listen")){

            /* Bind a sock to a card structure for listening 
             */         
            int err=0; 

            /* This is x25 specific area if protocol doesn't
                 * match, return error */
            if (sll->sll_protocol != htons(X25_PROT))
                  return -EINVAL;

            err= wanpipe_link_card (sk);
            if (err < 0)
                  return err;

            if (sll->sll_protocol)
                  wp->num = sll->sll_protocol;
            sk->sk_state = WANSOCK_BIND_LISTEN;
            return 0;

      }else if (!strcmp(sll->sll_device,"svc_connect")){ 

            /* This is x25 specific area if protocol doesn't
                 * match, return error */
            if (sll->sll_protocol != htons(X25_PROT))
                  return -EINVAL;

            /* Find a free device 
             */
            dev = wanpipe_find_free_dev(card);
            if (dev == NULL){
                  DBG_PRINTK(KERN_INFO "wansock: No free network devices for card %s\n",
                        card->devname);
                  return -EINVAL;
            }
      }else{
            /* Bind a socket to a interface name 
                 * This is used by PVC mostly
                 */
            strlcpy(name,sll->sll_device,sizeof(name));
            dev = dev_get_by_name(name);
            if (dev == NULL){
                  printk(KERN_INFO "wansock: Failed to get Dev from name: %s,\n",
                              name);
                  return -ENODEV;
            }

            dev_put(dev);

            if (check_dev(dev, card)){
                  printk(KERN_INFO "wansock: Device %s, doesn't belong to card %s\n",
                        dev->name, card->devname);
                  return -EINVAL;
            }
            if (get_atomic_device (dev))
                  return -EINVAL;
      }

      return wanpipe_do_bind(sk, dev, sll->sll_protocol ? : wp->num);
}

/*============================================================
 * get_atomic_device
 *    
 *    Sets a bit atomically which indicates that 
 *      the interface is taken. This avoids race conditions.
 *===========================================================*/


static inline int get_atomic_device(struct net_device *dev)
{
      wanpipe_common_t *chan = dev->priv;
      if (!test_and_set_bit(0,(void *)&chan->rw_bind)){
            return 0;
      }
      return 1;
}

/*============================================================
 * check_dev
 *    
 *    Check that device name belongs to a particular card.
 *===========================================================*/

static int check_dev(struct net_device *dev, sdla_t *card)
{
      struct net_device* tmp_dev;

      for (tmp_dev = card->wandev.dev; tmp_dev;
           tmp_dev = *((struct net_device **)tmp_dev->priv)) {
            if (tmp_dev->ifindex == dev->ifindex){ 
                  return 0;   
            }
      }
      return 1;
}

/*============================================================
 *  wanpipe_find_free_dev
 *    
 *    Find a free network interface. If found set atomic
 *      bit indicating that the interface is taken.
 *      X25API Specific.
 *===========================================================*/

struct net_device *wanpipe_find_free_dev(sdla_t *card)
{
      struct net_device* dev;
      volatile wanpipe_common_t *chan;

      if (test_and_set_bit(0,&find_free_critical)){
            printk(KERN_INFO "CRITICAL in Find Free\n");
      }     

      for (dev = card->wandev.dev; dev;
           dev = *((struct net_device **)dev->priv)) {
            chan = dev->priv;
            if (!chan) 
                  continue;
            if (chan->usedby == API && chan->svc){
                  if (!get_atomic_device (dev)){
                        if (chan->state != WANSOCK_DISCONNECTED){
                              release_device(dev);
                        }else{
                              clear_bit(0,&find_free_critical);
                              return dev;
                        }
                  }
            }
      }
      clear_bit(0,&find_free_critical);
      return NULL;
}

/*============================================================
 *  wanpipe_create
 *    
 *    SOCKET() System call.  It allocates a sock structure
 *      and adds the socket to the wanpipe_sk_list. 
 *      Crates AF_WANPIPE socket.
 *===========================================================*/

static int wanpipe_create(struct socket *sock, int protocol)
{
      struct sock *sk;
      
      //FIXME: This checks for root user, SECURITY ?
      //if (!capable(CAP_NET_RAW))
      //    return -EPERM;

      if (sock->type != SOCK_DGRAM && sock->type != SOCK_RAW)
            return -ESOCKTNOSUPPORT;

      sock->state = SS_UNCONNECTED;

      if ((sk = wanpipe_alloc_socket()) == NULL)
            return -ENOBUFS;

      sk->sk_reuse = 1;
      sock->ops = &wanpipe_ops;
      sock_init_data(sock,sk);

      sock_reset_flag(sk, SOCK_ZAPPED);
      sk->sk_family         = PF_WANPIPE;
      wp_sk(sk)->num        = protocol;
      sk->sk_state          = WANSOCK_DISCONNECTED;
      sk->sk_ack_backlog  = 0;
      sk->sk_bound_dev_if = 0;

      atomic_inc(&wanpipe_socks_nr);
      
      /* We must disable interrupts because the ISR
       * can also change the list */
      set_bit(1,&wanpipe_tx_critical);
      write_lock(&wanpipe_sklist_lock);
      sk_add_node(sk, &wanpipe_sklist);
      write_unlock(&wanpipe_sklist_lock);
      clear_bit(1,&wanpipe_tx_critical);

      return(0);
}


/*============================================================
 *  wanpipe_recvmsg
 *    
 *    Pull a packet from our receive queue and hand it 
 *      to the user. If necessary we block.
 *===========================================================*/

static int wanpipe_recvmsg(struct kiocb *iocb, struct socket *sock,
                     struct msghdr *msg, int len, int flags)
{
      struct sock *sk = sock->sk;
      struct sk_buff *skb;
      int copied, err=-ENOBUFS;


      /*
       *    If the address length field is there to be filled in, we fill
       *    it in now.
       */

      msg->msg_namelen = sizeof(struct wan_sockaddr_ll);

      /*
       *    Call the generic datagram receiver. This handles all sorts
       *    of horrible races and re-entrancy so we can forget about it
       *    in the protocol layers.
       *
       *    Now it will return ENETDOWN, if device have just gone down,
       *    but then it will block.
       */

      if (flags & MSG_OOB){   
            skb = skb_dequeue(&sk->sk_error_queue);
      }else{
            skb=skb_recv_datagram(sk,flags,1,&err);
      }
      /*
       *    An error occurred so return it. Because skb_recv_datagram() 
       *    handles the blocking we don't see and worry about blocking
       *    retries.
       */

      if(skb==NULL)
            goto out;

      /*
       *    You lose any data beyond the buffer you gave. If it worries a
       *    user program they can ask the device for its MTU anyway.
       */

      copied = skb->len;
      if (copied > len)
      {
            copied=len;
            msg->msg_flags|=MSG_TRUNC;
      }

      wanpipe_wakeup_driver(sk);

      /* We can't use skb_copy_datagram here */
      err = memcpy_toiovec(msg->msg_iov, skb->data, copied);
      if (err)
            goto out_free;
      
      sock_recv_timestamp(msg, sk, skb);
      
      if (msg->msg_name)
            memcpy(msg->msg_name, skb->cb, msg->msg_namelen);

      /*
       *    Free or return the buffer as appropriate. Again this
       *    hides all the races and re-entrancy issues from us.
       */
      err = (flags&MSG_TRUNC) ? skb->len : copied;

out_free:
      skb_free_datagram(sk, skb);
out:
      return err;
}


/*============================================================
 *  wanpipe_wakeup_driver
 *    
 *    If socket receive buffer is full and driver cannot
 *      pass data up the sock, it sets a packet_block flag.
 *      This function check that flag and if sock receive 
 *      queue has room it kicks the driver BH handler. 
 *
 *    This way, driver doesn't have to poll the sock 
 *      receive queue.
 *===========================================================*/

static void wanpipe_wakeup_driver(struct sock *sk)
{
      struct net_device *dev = NULL;
      wanpipe_common_t *chan=NULL;

      dev = dev_get_by_index(sk->sk_bound_dev_if);
      if (!dev)
            return;

      dev_put(dev);

      if ((chan = dev->priv) == NULL)
            return;
      
      if (atomic_read(&chan->receive_block)){  
            if (atomic_read(&sk->sk_rmem_alloc) <
                ((unsigned)sk->sk_rcvbuf * 0.9)) {
                  printk(KERN_INFO "wansock: Queuing task for wanpipe\n");
                  atomic_set(&chan->receive_block,0);
                  wanpipe_queue_tq(&chan->wanpipe_task);
                  wanpipe_mark_bh();
            }
      }     
}     

/*============================================================
 *  wanpipe_getname
 *    
 *    I don't know what to do with this yet. 
 *      User can use this function to get sock address
 *      information. Not very useful for Sangoma's purposes.
 *===========================================================*/


static int wanpipe_getname(struct socket *sock, struct sockaddr *uaddr,
                    int *uaddr_len, int peer)
{
      struct net_device *dev;
      struct sock *sk = sock->sk;
      struct wan_sockaddr_ll *sll = (struct wan_sockaddr_ll*)uaddr;

      sll->sll_family = AF_WANPIPE;
      sll->sll_ifindex = sk->sk_bound_dev_if;
      sll->sll_protocol = wp_sk(sk)->num;
      dev = dev_get_by_index(sk->sk_bound_dev_if);
      if (dev) {
            sll->sll_hatype = dev->type;
            sll->sll_halen = dev->addr_len;
            memcpy(sll->sll_addr, dev->dev_addr, dev->addr_len);
      } else {
            sll->sll_hatype = 0;    /* Bad: we have no ARPHRD_UNSPEC */
            sll->sll_halen = 0;
      }
      *uaddr_len = sizeof(*sll);
      
      dev_put(dev);
      
      return 0;
}

/*============================================================
 *  wanpipe_notifier
 *    
 *    If driver turns off network interface, this function
 *      will be envoked. Currently I treate it as a 
 *      call disconnect. More thought should go into this
 *      function.
 *
 * FIXME: More thought should go into this function.
 *
 *===========================================================*/

static int wanpipe_notifier(struct notifier_block *this, unsigned long msg, void *data)
{
      struct sock *sk;
      hlist_node *node;
      struct net_device *dev = (struct net_device *)data;

      sk_for_each(sk, node, &wanpipe_sklist) {
            struct wanpipe_opt *po = wp_sk(sk);

            if (!po)
                  continue;
            if (dev == NULL)
                  continue;
            
            switch (msg) {
            case NETDEV_DOWN:
            case NETDEV_UNREGISTER:
                  if (dev->ifindex == sk->sk_bound_dev_if) {
                        printk(KERN_INFO "wansock: Device down %s\n",dev->name);
                        if (sock_flag(sk, SOCK_ZAPPED)) {
                              wanpipe_unlink_driver(sk);
                              sk->sk_err = ENETDOWN;
                              sk->sk_error_report(sk);
                        }

                        if (msg == NETDEV_UNREGISTER) {
                              printk(KERN_INFO "wansock: Unregistering Device: %s\n",
                                            dev->name);
                              wanpipe_unlink_driver(sk);
                              sk->sk_bound_dev_if = 0;
                        }
                  }
                  break;
            case NETDEV_UP:
                  if (dev->ifindex == sk->sk_bound_dev_if &&
                      po->num && !sock_flag(sk, SOCK_ZAPPED)) {
                        printk(KERN_INFO "wansock: Registering Device: %s\n",
                                    dev->name);
                        wanpipe_link_driver(dev,sk);
                  }
                  break;
            }
      }
      return NOTIFY_DONE;
}

/*============================================================
 *  wanpipe_ioctl
 *    
 *    Execute a user commands, and set socket options.
 *
 * FIXME: More thought should go into this function.
 *
 *===========================================================*/

static int wanpipe_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
      struct sock *sk = sock->sk;
      int err;

      switch(cmd) 
      {
            case SIOCGSTAMP:
                  return sock_get_timestamp(sk, (struct timeval __user *)arg);

            case SIOC_WANPIPE_CHECK_TX:

                  return atomic_read(&sk->sk_wmem_alloc);

            case SIOC_WANPIPE_SOCK_STATE:

                  if (sk->sk_state == WANSOCK_CONNECTED)
                        return 0;
                  
                  return 1;


            case SIOC_WANPIPE_GET_CALL_DATA:

                  return get_ioctl_cmd (sk,(void*)arg);

            case SIOC_WANPIPE_SET_CALL_DATA:

                  return set_ioctl_cmd (sk,(void*)arg);

            case SIOC_WANPIPE_ACCEPT_CALL:
            case SIOC_WANPIPE_CLEAR_CALL:
            case SIOC_WANPIPE_RESET_CALL:

                  if ((err=set_ioctl_cmd(sk,(void*)arg)) < 0)
                        return err;

                  err=wanpipe_exec_cmd(sk,cmd,0);
                  get_ioctl_cmd(sk,(void*)arg);
                  return err;

            case SIOC_WANPIPE_DEBUG:

                  return wanpipe_debug(sk,(void*)arg);
      
            case SIOC_WANPIPE_SET_NONBLOCK:

                  if (sk->sk_state != WANSOCK_DISCONNECTED)
                        return -EINVAL;

                  sock->file->f_flags |= O_NONBLOCK;
                  return 0;
      
#ifdef CONFIG_INET
            case SIOCADDRT:
            case SIOCDELRT:
            case SIOCDARP:
            case SIOCGARP:
            case SIOCSARP:
            case SIOCDRARP:
            case SIOCGRARP:
            case SIOCSRARP:
            case SIOCGIFADDR:
            case SIOCSIFADDR:
            case SIOCGIFBRDADDR:
            case SIOCSIFBRDADDR:
            case SIOCGIFNETMASK:
            case SIOCSIFNETMASK:
            case SIOCGIFDSTADDR:
            case SIOCSIFDSTADDR:
            case SIOCSIFFLAGS:
                  return inet_dgram_ops.ioctl(sock, cmd, arg);
#endif

            default:
                  return -ENOIOCTLCMD;
      }
      /*NOTREACHED*/
}

/*============================================================
 *  wanpipe_debug
 *    
 *    This function will pass up information about all
 *      active sockets.
 *
 * FIXME: More thought should go into this function.
 *
 *===========================================================*/

static int wanpipe_debug (struct sock *origsk, void *arg)
{
      struct sock *sk;
      struct hlist_node *node;
      struct net_device *dev = NULL;
      wanpipe_common_t *chan=NULL;
      int cnt=0, err=0;
      wan_debug_t *dbg_data = (wan_debug_t *)arg;

      sk_for_each(sk, node, &wanpipe_sklist) {
            wanpipe_opt *wp = wp_sk(sk);

            if (sk == origsk){
                  continue;
            }

            if ((err=put_user(1, &dbg_data->debug[cnt].free)))
                  return err;
            if ((err = put_user(sk->sk_state,
                            &dbg_data->debug[cnt].state_sk)))
                  return err;
            if ((err = put_user(sk->sk_rcvbuf,
                            &dbg_data->debug[cnt].rcvbuf)))
                  return err;
            if ((err = put_user(atomic_read(&sk->sk_rmem_alloc),
                            &dbg_data->debug[cnt].rmem)))
                  return err;
            if ((err = put_user(atomic_read(&sk->sk_wmem_alloc),
                            &dbg_data->debug[cnt].wmem)))
                  return err;
            if ((err = put_user(sk->sk_sndbuf,
                            &dbg_data->debug[cnt].sndbuf)))
                  return err;
            if ((err=put_user(sk_count, &dbg_data->debug[cnt].sk_count)))
                  return err;
            if ((err=put_user(wp->poll_cnt, &dbg_data->debug[cnt].poll_cnt)))
                  return err;
            if ((err = put_user(sk->sk_bound_dev_if,
                            &dbg_data->debug[cnt].bound)))
                  return err;

            if (sk->sk_bound_dev_if) {
                  dev = dev_get_by_index(sk->sk_bound_dev_if);
                  if (!dev)   
                        continue;

                  chan=dev->priv;
                  dev_put(dev);
      
                  if ((err=put_user(chan->state, &dbg_data->debug[cnt].d_state)))
                        return err;
                  if ((err=put_user(chan->svc, &dbg_data->debug[cnt].svc)))
                        return err;

                  if ((err=put_user(atomic_read(&chan->command), 
                                    &dbg_data->debug[cnt].command)))
                        return err;


                  if (wp){
                        sdla_t *card = (sdla_t*)wp->card;               
      
                        if (card){
                              if ((err=put_user(atomic_read(&card->u.x.command_busy), 
                                                &dbg_data->debug[cnt].cmd_busy)))
                                    return err;
                        }

                        if ((err=put_user(wp->lcn, 
                                      &dbg_data->debug[cnt].lcn)))
                              return err;
                        
                        if (wp->mbox) {
                              if ((err=put_user(1, &dbg_data->debug[cnt].mbox)))
                                    return err;
                        }
                  }

                  if ((err=put_user(atomic_read(&chan->receive_block), 
                                                &dbg_data->debug[cnt].rblock)))
                        return err;

                  if (copy_to_user(dbg_data->debug[cnt].name, dev->name, strlen(dev->name)))
                        return -EFAULT;
            }
      
            if (++cnt == MAX_NUM_DEBUG)
                  break;
      }
      return 0;
}

/*============================================================
 *  get_ioctl_cmd
 *    
 *    Pass up the contents of socket MBOX to the user.
 *===========================================================*/

static int get_ioctl_cmd (struct sock *sk, void *arg)
{
      x25api_t *usr_data = (x25api_t *)arg;
      mbox_cmd_t *mbox_ptr;
      int err;

      if (usr_data == NULL)
            return -EINVAL;

      if (!wp_sk(sk)->mbox) {
            return -EINVAL;
      }

      mbox_ptr = (mbox_cmd_t *)wp_sk(sk)->mbox;

      if ((err=put_user(mbox_ptr->cmd.qdm, &usr_data->hdr.qdm)))
            return err;
      if ((err=put_user(mbox_ptr->cmd.cause, &usr_data->hdr.cause)))
            return err;
      if ((err=put_user(mbox_ptr->cmd.diagn, &usr_data->hdr.diagn)))
            return err;
      if ((err=put_user(mbox_ptr->cmd.length, &usr_data->hdr.length)))
            return err;
      if ((err=put_user(mbox_ptr->cmd.result, &usr_data->hdr.result)))
            return err;
      if ((err=put_user(mbox_ptr->cmd.lcn, &usr_data->hdr.lcn)))
            return err; 

      if (mbox_ptr->cmd.length > 0){
            if (mbox_ptr->cmd.length > X25_MAX_DATA)
                  return -EINVAL;

            if (copy_to_user(usr_data->data, mbox_ptr->data, mbox_ptr->cmd.length)){
                  printk(KERN_INFO "wansock: Copy failed !!!\n");
                  return -EFAULT;
            }
      }
      return 0;
} 

/*============================================================
 *  set_ioctl_cmd
 *    
 *    Before command can be execute, socket MBOX must
 *      be created, and initialized with user data.   
 *===========================================================*/

static int set_ioctl_cmd (struct sock *sk, void *arg)
{
      x25api_t *usr_data = (x25api_t *)arg;
      mbox_cmd_t *mbox_ptr;
      int err;

      if (!wp_sk(sk)->mbox) {
            void *mbox_ptr;
            struct net_device *dev = dev_get_by_index(sk->sk_bound_dev_if);
            if (!dev)
                  return -ENODEV;

            dev_put(dev);
            
            if ((mbox_ptr = kzalloc(sizeof(mbox_cmd_t), GFP_ATOMIC)) == NULL)
                  return -ENOMEM;

            wp_sk(sk)->mbox = mbox_ptr;

            wanpipe_link_driver(dev,sk);
      }

      mbox_ptr = (mbox_cmd_t*)wp_sk(sk)->mbox;
      memset(mbox_ptr, 0, sizeof(mbox_cmd_t));

      if (usr_data == NULL){
            return 0;
      }
      if ((err=get_user(mbox_ptr->cmd.qdm, &usr_data->hdr.qdm)))
            return err;
      if ((err=get_user(mbox_ptr->cmd.cause, &usr_data->hdr.cause)))
            return err;
      if ((err=get_user(mbox_ptr->cmd.diagn, &usr_data->hdr.diagn)))
            return err;
      if ((err=get_user(mbox_ptr->cmd.length, &usr_data->hdr.length)))
            return err;
      if ((err=get_user(mbox_ptr->cmd.result, &usr_data->hdr.result)))
            return err;

      if (mbox_ptr->cmd.length > 0){
            if (mbox_ptr->cmd.length > X25_MAX_DATA)
                  return -EINVAL;

            if (copy_from_user(mbox_ptr->data, usr_data->data, mbox_ptr->cmd.length)){
                  printk(KERN_INFO "Copy failed\n");
                  return -EFAULT;
            }
      }
      return 0;
}


/*======================================================================
 * wanpipe_poll
 *
 *    Datagram poll: Again totally generic. This also handles
 *    sequenced packet sockets providing the socket receive queue
 *    is only ever holding data ready to receive.
 *
 *    Note: when you _don't_ use this routine for this protocol,
 *    and you use a different write policy from sock_writeable()
 *    then please supply your own write_space callback.
 *=====================================================================*/

unsigned int wanpipe_poll(struct file * file, struct socket *sock, poll_table *wait)
{
      struct sock *sk = sock->sk;
      unsigned int mask;

      ++wp_sk(sk)->poll_cnt;

      poll_wait(file, sk->sk_sleep, wait);
      mask = 0;

      /* exceptional events? */
      if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) {
            mask |= POLLPRI;
            return mask;
      }
      if (sk->sk_shutdown & RCV_SHUTDOWN)
            mask |= POLLHUP;

      /* readable? */
      if (!skb_queue_empty(&sk->sk_receive_queue)) {
            mask |= POLLIN | POLLRDNORM;
      }

      /* connection hasn't started yet */
      if (sk->sk_state == WANSOCK_CONNECTING) {
            return mask;
      }

      if (sk->sk_state == WANSOCK_DISCONNECTED) {
            mask = POLLPRI;
            return mask;
      }

      /* This check blocks the user process if there is   
       * a packet already queued in the socket write queue.
         * This option is only for X25API protocol, for other
         * protocol like chdlc enable streaming mode, 
         * where multiple packets can be pending in the socket 
         * transmit queue */

      if (wp_sk(sk)->num == htons(X25_PROT)) {
            if (atomic_read(&wp_sk(sk)->packet_sent))
                  return mask;
      }

      /* writable? */
      if (sock_writeable(sk)){
            mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
      }else{
            set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
      }
            
      return mask;
}

/*======================================================================
 * wanpipe_listen
 *
 *    X25API Specific function. Set a socket into LISTENING  MODE.
 *=====================================================================*/


static int wanpipe_listen(struct socket *sock, int backlog)
{
      struct sock *sk = sock->sk;

      /* This is x25 specific area if protocol doesn't
         * match, return error */
      if (wp_sk(sk)->num != htons(X25_PROT))
            return -EINVAL;

      if (sk->sk_state == WANSOCK_BIND_LISTEN) {

            sk->sk_max_ack_backlog = backlog;
            sk->sk_state           = WANSOCK_LISTEN;
            return 0;
      }else{
            printk(KERN_INFO "wansock: Listening sock was not binded\n");
      }

      return -EINVAL;
}

/*======================================================================
 * wanpipe_link_card
 *
 *    Connects the listening socket to the driver
 *=====================================================================*/

static int wanpipe_link_card (struct sock *sk)
{
      sdla_t *card = (sdla_t*)wp_sk(sk)->card;

      if (!card)
            return -ENOMEM;

      if ((card->sk != NULL) || (card->func != NULL)){
            printk(KERN_INFO "wansock: Listening queue is already established\n");
            return -EINVAL;
      }

      card->sk=sk;
      card->func=wanpipe_listen_rcv;
      sock_set_flag(sk, SOCK_ZAPPED);
 
      return 0;
}

/*======================================================================
 * wanpipe_listen
 *
 *    X25API Specific function. Disconnect listening socket from
 *      the driver.
 *=====================================================================*/

static void wanpipe_unlink_card (struct sock *sk)
{
      sdla_t *card = (sdla_t*)wp_sk(sk)->card; 

      if (card){
            card->sk=NULL;
            card->func=NULL;
      }
}

/*======================================================================
 * wanpipe_exec_cmd
 *
 *    Ioctl function calls this function to execute user command.
 *      Connect() sytem call also calls this function to execute
 *      place call.  This function blocks until command is executed.
 *=====================================================================*/

static int wanpipe_exec_cmd(struct sock *sk, int cmd, unsigned int flags)
{
      int err = -EINVAL;
      wanpipe_opt *wp = wp_sk(sk);
      mbox_cmd_t *mbox_ptr = (mbox_cmd_t*)wp->mbox;

      if (!mbox_ptr){
            printk(KERN_INFO "NO MBOX PTR !!!!!\n");
            return -EINVAL;
      }
      
      /* This is x25 specific area if protocol doesn't
         * match, return error */
      if (wp->num != htons(X25_PROT))
            return -EINVAL;


      switch (cmd){

            case SIOC_WANPIPE_ACCEPT_CALL:

                  if (sk->sk_state != WANSOCK_CONNECTING) {
                        err = -EHOSTDOWN;
                        break;
                  }
                  
                  err = execute_command(sk,X25_ACCEPT_CALL,0);
                  if (err < 0)
                        break;

                  /* Update. Mar6 2000. 
                         * Do not set the sock lcn number here, since
                         * it is done in wanpipe_listen_rcv(). 
                         */ 
                  if (sk->sk_state == WANSOCK_CONNECTED) {
                        wp->lcn = ((mbox_cmd_t*)wp->mbox)->cmd.lcn;     
                        DBG_PRINTK(KERN_INFO "\nwansock: Accept OK %i\n",
                              wp->lcn);
                        err = 0;

                  }else{
                        DBG_PRINTK (KERN_INFO "\nwansock: Accept Failed %i\n",
                              wp->lcn);
                        wp->lcn = 0;
                        err = -ECONNREFUSED;
                  }
                  break;

            case SIOC_WANPIPE_CLEAR_CALL:

                  if (sk->sk_state == WANSOCK_DISCONNECTED) {
                        err = -EINVAL;
                        break;
                  }


                  /* Check if data buffers are pending for transmission,
                         * if so, check whether user wants to wait until data
                         * is transmitted, or clear a call and drop packets */
                          
                  if (atomic_read(&sk->sk_wmem_alloc) ||
                      check_driver_busy(sk)) {
                        mbox_cmd_t *mbox = wp->mbox;
                        if (mbox->cmd.qdm & 0x80){
                              mbox->cmd.result = 0x35;
                              err = -EAGAIN;    
                              break;
                        }
                  }

                  sk->sk_state = WANSOCK_DISCONNECTING;

                  err = execute_command(sk,X25_CLEAR_CALL,0);
                  if (err < 0)
                        break;

                  err = -ECONNREFUSED;
                  if (sk->sk_state == WANSOCK_DISCONNECTED) {
                        DBG_PRINTK(KERN_INFO "\nwansock: CLEAR OK %i\n",
                                 wp->lcn);
                        wp->lcn = 0;
                        err = 0;
                  }
                  break;

            case SIOC_WANPIPE_RESET_CALL:

                  if (sk->sk_state != WANSOCK_CONNECTED) {
                        err = -EINVAL;
                        break;
                  }


                  /* Check if data buffers are pending for transmission,
                         * if so, check whether user wants to wait until data
                         * is transmitted, or reset a call and drop packets */
                          
                  if (atomic_read(&sk->sk_wmem_alloc) ||
                      check_driver_busy(sk)) {
                        mbox_cmd_t *mbox = wp->mbox;
                        if (mbox->cmd.qdm & 0x80){
                              mbox->cmd.result = 0x35;
                              err = -EAGAIN;    
                              break;
                        }
                  }


                  err = execute_command(sk, X25_RESET,0);
                  if (err < 0)
                        break;

                  err = mbox_ptr->cmd.result;
                  break;


            case X25_PLACE_CALL:

                  err=execute_command(sk,X25_PLACE_CALL,flags);
                  if (err < 0)
                        break;

                  if (sk->sk_state == WANSOCK_CONNECTED) {

                        wp->lcn = ((mbox_cmd_t*)wp->mbox)->cmd.lcn;     

                        DBG_PRINTK(KERN_INFO "\nwansock: PLACE CALL OK %i\n",
                              wp->lcn);
                        err = 0;

                  } else if (sk->sk_state == WANSOCK_CONNECTING &&
                           (flags & O_NONBLOCK)) {
                        wp->lcn = ((mbox_cmd_t*)wp->mbox)->cmd.lcn;
                        DBG_PRINTK(KERN_INFO "\nwansock: Place Call OK: Waiting %i\n",
                              wp->lcn);

                        err = 0;

                  }else{
                        DBG_PRINTK(KERN_INFO "\nwansock: Place call Failed\n");
                        err = -ECONNREFUSED;
                  }

                  break;

            default: 
                  return -EINVAL;
      }

      return err;
}

static int check_driver_busy (struct sock *sk)
{
      struct net_device *dev = dev_get_by_index(sk->sk_bound_dev_if);
      wanpipe_common_t *chan;

      if (!dev)
            return 0;

      dev_put(dev);

      if ((chan=dev->priv) == NULL)
            return 0;

      return atomic_read(&chan->driver_busy);
}


/*======================================================================
 * wanpipe_accept
 *
 *    ACCEPT() System call.   X25API Specific function. 
 *    For each incoming call, create a new socket and 
 *      return it to the user.      
 *=====================================================================*/

static int wanpipe_accept(struct socket *sock, struct socket *newsock, int flags)
{
      struct sock *sk;
      struct sock *newsk;
      struct sk_buff *skb;
      DECLARE_WAITQUEUE(wait, current);
      int err=0;

      if (newsock->sk != NULL){
            wanpipe_kill_sock_accept(newsock->sk);    
            newsock->sk=NULL;
      }
      
      if ((sk = sock->sk) == NULL)
            return -EINVAL;

      if (sk->sk_type != SOCK_RAW)
            return -EOPNOTSUPP;

      if (sk->sk_state != WANSOCK_LISTEN)
            return -EINVAL;

      if (wp_sk(sk)->num != htons(X25_PROT))
            return -EINVAL;

      add_wait_queue(sk->sk_sleep,&wait);
      current->state = TASK_INTERRUPTIBLE;
      for (;;){
            skb = skb_dequeue(&sk->sk_receive_queue);
            if (skb){
                  err=0;
                  break;
            }
            if (signal_pending(current)) {
                  err = -ERESTARTSYS;
                  break;
            }
            schedule();
      }
      current->state = TASK_RUNNING;
      remove_wait_queue(sk->sk_sleep,&wait);
      
      if (err != 0)
            return err;
      
      newsk = get_newsk_from_skb(skb);
      if (!newsk){
            return -EINVAL;
      }

      set_bit(1,&wanpipe_tx_critical);
      write_lock(&wanpipe_sklist_lock);
      sk_add_node(newsk, &wanpipe_sklist);
      write_unlock(&wanpipe_sklist_lock);
      clear_bit(1,&wanpipe_tx_critical);

      newsk->sk_socket = newsock;
      newsk->sk_sleep = &newsock->wait;

      /* Now attach up the new socket */
      sk->sk_ack_backlog--;
      newsock->sk = newsk;
      
      kfree_skb(skb);

      DBG_PRINTK(KERN_INFO "\nwansock: ACCEPT Got LCN %i\n",
               wp_sk(newsk)->lcn);
      return 0;
}

/*======================================================================
 *  get_newsk_from_skb
 *
 *    Accept() uses this function to get the address of the new
 *      socket structure.
 *=====================================================================*/

struct sock * get_newsk_from_skb (struct sk_buff *skb)
{
      struct net_device *dev = skb->dev;
      wanpipe_common_t *chan; 

      if (!dev){
            return NULL;
      }
            
      if ((chan = dev->priv) == NULL){
            return NULL;
      }
            
      if (!chan->sk){
            return NULL;
      }
      return (struct sock *)chan->sk;
}

/*======================================================================
 *  wanpipe_connect
 *
 *    CONNECT() System Call. X25API specific function
 *    Check the state of the sock, and execute PLACE_CALL command.
 *      Connect can ether block or return without waiting for connection, 
 *      if specified by user.
 *=====================================================================*/

static int wanpipe_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags)
{
      struct sock *sk = sock->sk;
      struct wan_sockaddr_ll *addr = (struct wan_sockaddr_ll*)uaddr;
      struct net_device *dev;
      int err;

      if (wp_sk(sk)->num != htons(X25_PROT))
            return -EINVAL;

      if (sk->sk_state == WANSOCK_CONNECTED)
            return -EISCONN;  /* No reconnect on a seqpacket socket */

      if (sk->sk_state != WAN_DISCONNECTED) {
            printk(KERN_INFO "wansock: Trying to connect on channel NON DISCONNECT\n");
            return -ECONNREFUSED;
      }

      sk->sk_state = WANSOCK_DISCONNECTED;      
      sock->state  = SS_UNCONNECTED;

      if (addr_len != sizeof(struct wan_sockaddr_ll))
            return -EINVAL;

      if (addr->sll_family != AF_WANPIPE)
            return -EINVAL;

      if ((dev = dev_get_by_index(sk->sk_bound_dev_if)) == NULL)
            return -ENETUNREACH;

      dev_put(dev);
      
      if (!sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
            return -EINVAL;

      sock->state   = SS_CONNECTING;
      sk->sk_state  = WANSOCK_CONNECTING;

      if (!wp_sk(sk)->mbox) {
            if (wp_sk (sk)->svc)
                  return -EINVAL;
            else {
                  int err;
                  if ((err=set_ioctl_cmd(sk,NULL)) < 0)
                        return err;
            }
      }

      if ((err=wanpipe_exec_cmd(sk, X25_PLACE_CALL,flags)) != 0){
            sock->state = SS_UNCONNECTED;
            sk->sk_state = WANSOCK_CONNECTED;
            return err;
      }

      if (sk->sk_state != WANSOCK_CONNECTED && (flags & O_NONBLOCK)) {
            return 0;
      }

      if (sk->sk_state != WANSOCK_CONNECTED) {
            sock->state = SS_UNCONNECTED;
            return -ECONNREFUSED; 
      }

      sock->state = SS_CONNECTED;
      return 0;
}

const struct proto_ops wanpipe_ops = {
      .family =   PF_WANPIPE,
      .owner =    THIS_MODULE,
      .release =  wanpipe_release,
      .bind =     wanpipe_bind,
      .connect =  wanpipe_connect,
      .socketpair =     sock_no_socketpair,
      .accept =   wanpipe_accept,
      .getname =  wanpipe_getname, 
      .poll =     wanpipe_poll,
      .ioctl =    wanpipe_ioctl,
      .listen =   wanpipe_listen, 
      .shutdown =       sock_no_shutdown,
      .setsockopt =     sock_no_setsockopt,
      .getsockopt =     sock_no_getsockopt,
      .sendmsg =  wanpipe_sendmsg,
      .recvmsg =  wanpipe_recvmsg
};

static struct net_proto_family wanpipe_family_ops = {
      .family = PF_WANPIPE,
      .create = wanpipe_create,
      .owner      = THIS_MODULE,
};

struct notifier_block wanpipe_netdev_notifier = {
      .notifier_call = wanpipe_notifier,
};


#ifdef MODULE
void cleanup_module(void)
{
      printk(KERN_INFO "wansock: Cleaning up \n");
      unregister_netdevice_notifier(&wanpipe_netdev_notifier);
      sock_unregister(PF_WANPIPE);
      proto_unregister(&wanpipe_proto);
}

int init_module(void)
{
      int rc;

      printk(KERN_INFO "wansock: Registering Socket \n");

      rc = proto_register(&wanpipe_proto, 0);
      if (rc != 0)
            goto out;

      sock_register(&wanpipe_family_ops);
      register_netdevice_notifier(&wanpipe_netdev_notifier);
out:
      return rc;
}
#endif
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_WANPIPE);

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