path: root/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 Technologies
*               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 application 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);