Linux-2.6.12-rc2

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / wanrouter / 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/config.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.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/wanpipe.h>
#include <linux/if_wanpipe.h>
#include <linux/pkt_sched.h>
#include <linux/tcp.h>
#include <linux/if_wanpipe_common.h>
#include <linux/sdla_x25.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 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 = kmalloc(sizeof(mbox_cmd_t), GFP_ATOMIC)) == NULL) {
                wanpipe_kill_sock_irq (newsk);
                release_device(dev);            
                return -ENOMEM;
        }
        memset(mbox_ptr, 0, sizeof(mbox_cmd_t));
        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 = kmalloc(sizeof(struct wanpipe_opt), GFP_ATOMIC)) == NULL) {
                sk_free(sk);
                return NULL;
        }
        memset(wan_opt, 0x00, sizeof(struct wanpipe_opt));

        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 && wp->mbox) {
                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;
        }

        if (wp_sk(sk)) {
                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;


        if (wp_sk(sk)) {
                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;

        if (wp_sk(sk)) {
                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 dev_ioctl(cmd,(void __user *) arg);
        }
        /*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 = kmalloc(sizeof(mbox_cmd_t), GFP_ATOMIC)) == NULL)
                        return -ENOMEM;

                memset(mbox_ptr, 0, sizeof(mbox_cmd_t));
                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;
}

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);