[NET]: Transform skb_queue_len() binary tests into skb_queue_empty()

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / irda / irlap.c

/*********************************************************************
 *
 * Filename:      irlap.c
 * Version:       1.0
 * Description:   IrLAP implementation for Linux
 * Status:        Stable
 * Author:        Dag Brattli <dagb@cs.uit.no>
 * Created at:    Mon Aug  4 20:40:53 1997
 * Modified at:   Tue Dec 14 09:26:44 1999
 * Modified by:   Dag Brattli <dagb@cs.uit.no>
 *
 *     Copyright (c) 1998-1999 Dag Brattli, All Rights Reserved.
 *     Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
 *
 *     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.
 *
 *     This program is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *     GNU General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public License
 *     along with this program; if not, write to the Free Software
 *     Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *     MA 02111-1307 USA
 *
 ********************************************************************/

#include <linux/config.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/module.h>
#include <linux/seq_file.h>

#include <net/irda/irda.h>
#include <net/irda/irda_device.h>
#include <net/irda/irqueue.h>
#include <net/irda/irlmp.h>
#include <net/irda/irlmp_frame.h>
#include <net/irda/irlap_frame.h>
#include <net/irda/irlap.h>
#include <net/irda/timer.h>
#include <net/irda/qos.h>

static hashbin_t *irlap = NULL;
int sysctl_slot_timeout = SLOT_TIMEOUT * 1000 / HZ;

/* This is the delay of missed pf period before generating an event
 * to the application. The spec mandate 3 seconds, but in some cases
 * it's way too long. - Jean II */
int sysctl_warn_noreply_time = 3;

extern void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb);
static void __irlap_close(struct irlap_cb *self);
static void irlap_init_qos_capabilities(struct irlap_cb *self,
                                        struct qos_info *qos_user);

#ifdef CONFIG_IRDA_DEBUG
static char *lap_reasons[] = {
        "ERROR, NOT USED",
        "LAP_DISC_INDICATION",
        "LAP_NO_RESPONSE",
        "LAP_RESET_INDICATION",
        "LAP_FOUND_NONE",
        "LAP_MEDIA_BUSY",
        "LAP_PRIMARY_CONFLICT",
        "ERROR, NOT USED",
};
#endif  /* CONFIG_IRDA_DEBUG */

int __init irlap_init(void)
{
        /* Check if the compiler did its job properly.
         * May happen on some ARM configuration, check with Russell King. */
        IRDA_ASSERT(sizeof(struct xid_frame) == 14, ;);
        IRDA_ASSERT(sizeof(struct test_frame) == 10, ;);
        IRDA_ASSERT(sizeof(struct ua_frame) == 10, ;);
        IRDA_ASSERT(sizeof(struct snrm_frame) == 11, ;);

        /* Allocate master array */
        irlap = hashbin_new(HB_LOCK);
        if (irlap == NULL) {
                IRDA_ERROR("%s: can't allocate irlap hashbin!\n",
                           __FUNCTION__);
                return -ENOMEM;
        }

        return 0;
}

void __exit irlap_cleanup(void)
{
        IRDA_ASSERT(irlap != NULL, return;);

        hashbin_delete(irlap, (FREE_FUNC) __irlap_close);
}

/*
 * Function irlap_open (driver)
 *
 *    Initialize IrLAP layer
 *
 */
struct irlap_cb *irlap_open(struct net_device *dev, struct qos_info *qos,
                            const char *hw_name)
{
        struct irlap_cb *self;

        IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

        /* Initialize the irlap structure. */
        self = kmalloc(sizeof(struct irlap_cb), GFP_KERNEL);
        if (self == NULL)
                return NULL;

        memset(self, 0, sizeof(struct irlap_cb));
        self->magic = LAP_MAGIC;

        /* Make a binding between the layers */
        self->netdev = dev;
        self->qos_dev = qos;
        /* Copy hardware name */
        if(hw_name != NULL) {
                strlcpy(self->hw_name, hw_name, sizeof(self->hw_name));
        } else {
                self->hw_name[0] = '\0';
        }

        /* FIXME: should we get our own field? */
        dev->atalk_ptr = self;

        self->state = LAP_OFFLINE;

        /* Initialize transmit queue */
        skb_queue_head_init(&self->txq);
        skb_queue_head_init(&self->txq_ultra);
        skb_queue_head_init(&self->wx_list);

        /* My unique IrLAP device address! */
        /* We don't want the broadcast address, neither the NULL address
         * (most often used to signify "invalid"), and we don't want an
         * address already in use (otherwise connect won't be able
         * to select the proper link). - Jean II */
        do {
                get_random_bytes(&self->saddr, sizeof(self->saddr));
        } while ((self->saddr == 0x0) || (self->saddr == BROADCAST) ||
                 (hashbin_lock_find(irlap, self->saddr, NULL)) );
        /* Copy to the driver */
        memcpy(dev->dev_addr, &self->saddr, 4);

        init_timer(&self->slot_timer);
        init_timer(&self->query_timer);
        init_timer(&self->discovery_timer);
        init_timer(&self->final_timer);
        init_timer(&self->poll_timer);
        init_timer(&self->wd_timer);
        init_timer(&self->backoff_timer);
        init_timer(&self->media_busy_timer);

        irlap_apply_default_connection_parameters(self);

        self->N3 = 3; /* # connections attemts to try before giving up */

        self->state = LAP_NDM;

        hashbin_insert(irlap, (irda_queue_t *) self, self->saddr, NULL);

        irlmp_register_link(self, self->saddr, &self->notify);

        return self;
}
EXPORT_SYMBOL(irlap_open);

/*
 * Function __irlap_close (self)
 *
 *    Remove IrLAP and all allocated memory. Stop any pending timers.
 *
 */
static void __irlap_close(struct irlap_cb *self)
{
        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        /* Stop timers */
        del_timer(&self->slot_timer);
        del_timer(&self->query_timer);
        del_timer(&self->discovery_timer);
        del_timer(&self->final_timer);
        del_timer(&self->poll_timer);
        del_timer(&self->wd_timer);
        del_timer(&self->backoff_timer);
        del_timer(&self->media_busy_timer);

        irlap_flush_all_queues(self);

        self->magic = 0;

        kfree(self);
}

/*
 * Function irlap_close (self)
 *
 *    Remove IrLAP instance
 *
 */
void irlap_close(struct irlap_cb *self)
{
        struct irlap_cb *lap;

        IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        /* We used to send a LAP_DISC_INDICATION here, but this was
         * racy. This has been move within irlmp_unregister_link()
         * itself. Jean II */

        /* Kill the LAP and all LSAPs on top of it */
        irlmp_unregister_link(self->saddr);
        self->notify.instance = NULL;

        /* Be sure that we manage to remove ourself from the hash */
        lap = hashbin_remove(irlap, self->saddr, NULL);
        if (!lap) {
                IRDA_DEBUG(1, "%s(), Didn't find myself!\n", __FUNCTION__);
                return;
        }
        __irlap_close(lap);
}
EXPORT_SYMBOL(irlap_close);

/*
 * Function irlap_connect_indication (self, skb)
 *
 *    Another device is attempting to make a connection
 *
 */
void irlap_connect_indication(struct irlap_cb *self, struct sk_buff *skb)
{
        IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        irlap_init_qos_capabilities(self, NULL); /* No user QoS! */

        irlmp_link_connect_indication(self->notify.instance, self->saddr,
                                      self->daddr, &self->qos_tx, skb);
}

/*
 * Function irlap_connect_response (self, skb)
 *
 *    Service user has accepted incoming connection
 *
 */
void irlap_connect_response(struct irlap_cb *self, struct sk_buff *userdata)
{
        IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

        irlap_do_event(self, CONNECT_RESPONSE, userdata, NULL);
}

/*
 * Function irlap_connect_request (self, daddr, qos_user, sniff)
 *
 *    Request connection with another device, sniffing is not implemented
 *    yet.
 *
 */
void irlap_connect_request(struct irlap_cb *self, __u32 daddr,
                           struct qos_info *qos_user, int sniff)
{
        IRDA_DEBUG(3, "%s(), daddr=0x%08x\n", __FUNCTION__, daddr);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        self->daddr = daddr;

        /*
         *  If the service user specifies QoS values for this connection,
         *  then use them
         */
        irlap_init_qos_capabilities(self, qos_user);

        if ((self->state == LAP_NDM) && !self->media_busy)
                irlap_do_event(self, CONNECT_REQUEST, NULL, NULL);
        else
                self->connect_pending = TRUE;
}

/*
 * Function irlap_connect_confirm (self, skb)
 *
 *    Connection request has been accepted
 *
 */
void irlap_connect_confirm(struct irlap_cb *self, struct sk_buff *skb)
{
        IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        irlmp_link_connect_confirm(self->notify.instance, &self->qos_tx, skb);
}

/*
 * Function irlap_data_indication (self, skb)
 *
 *    Received data frames from IR-port, so we just pass them up to
 *    IrLMP for further processing
 *
 */
void irlap_data_indication(struct irlap_cb *self, struct sk_buff *skb,
                           int unreliable)
{
        /* Hide LAP header from IrLMP layer */
        skb_pull(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);

        irlmp_link_data_indication(self->notify.instance, skb, unreliable);
}


/*
 * Function irlap_data_request (self, skb)
 *
 *    Queue data for transmission, must wait until XMIT state
 *
 */
void irlap_data_request(struct irlap_cb *self, struct sk_buff *skb,
                        int unreliable)
{
        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        IRDA_DEBUG(3, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(skb_headroom(skb) >= (LAP_ADDR_HEADER+LAP_CTRL_HEADER),
                    return;);
        skb_push(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);

        /*
         *  Must set frame format now so that the rest of the code knows
         *  if its dealing with an I or an UI frame
         */
        if (unreliable)
                skb->data[1] = UI_FRAME;
        else
                skb->data[1] = I_FRAME;

        /* Don't forget to refcount it - see irlmp_connect_request(). */
        skb_get(skb);

        /* Add at the end of the queue (keep ordering) - Jean II */
        skb_queue_tail(&self->txq, skb);

        /*
         *  Send event if this frame only if we are in the right state
         *  FIXME: udata should be sent first! (skb_queue_head?)
         */
        if ((self->state == LAP_XMIT_P) || (self->state == LAP_XMIT_S)) {
                /* If we are not already processing the Tx queue, trigger
                 * transmission immediately - Jean II */
                if((skb_queue_len(&self->txq) <= 1) && (!self->local_busy))
                        irlap_do_event(self, DATA_REQUEST, skb, NULL);
                /* Otherwise, the packets will be sent normally at the
                 * next pf-poll - Jean II */
        }
}

/*
 * Function irlap_unitdata_request (self, skb)
 *
 *    Send Ultra data. This is data that must be sent outside any connection
 *
 */
#ifdef CONFIG_IRDA_ULTRA
void irlap_unitdata_request(struct irlap_cb *self, struct sk_buff *skb)
{
        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        IRDA_DEBUG(3, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(skb_headroom(skb) >= (LAP_ADDR_HEADER+LAP_CTRL_HEADER),
               return;);
        skb_push(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);

        skb->data[0] = CBROADCAST;
        skb->data[1] = UI_FRAME;

        /* Don't need to refcount, see irlmp_connless_data_request() */

        skb_queue_tail(&self->txq_ultra, skb);

        irlap_do_event(self, SEND_UI_FRAME, NULL, NULL);
}
#endif /*CONFIG_IRDA_ULTRA */

/*
 * Function irlap_udata_indication (self, skb)
 *
 *    Receive Ultra data. This is data that is received outside any connection
 *
 */
#ifdef CONFIG_IRDA_ULTRA
void irlap_unitdata_indication(struct irlap_cb *self, struct sk_buff *skb)
{
        IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
        IRDA_ASSERT(skb != NULL, return;);

        /* Hide LAP header from IrLMP layer */
        skb_pull(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);

        irlmp_link_unitdata_indication(self->notify.instance, skb);
}
#endif /* CONFIG_IRDA_ULTRA */

/*
 * Function irlap_disconnect_request (void)
 *
 *    Request to disconnect connection by service user
 */
void irlap_disconnect_request(struct irlap_cb *self)
{
        IRDA_DEBUG(3, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        /* Don't disconnect until all data frames are successfully sent */
        if (!skb_queue_empty(&self->txq)) {
                self->disconnect_pending = TRUE;
                return;
        }

        /* Check if we are in the right state for disconnecting */
        switch (self->state) {
        case LAP_XMIT_P:        /* FALLTROUGH */
        case LAP_XMIT_S:        /* FALLTROUGH */
        case LAP_CONN:          /* FALLTROUGH */
        case LAP_RESET_WAIT:    /* FALLTROUGH */
        case LAP_RESET_CHECK:
                irlap_do_event(self, DISCONNECT_REQUEST, NULL, NULL);
                break;
        default:
                IRDA_DEBUG(2, "%s(), disconnect pending!\n", __FUNCTION__);
                self->disconnect_pending = TRUE;
                break;
        }
}

/*
 * Function irlap_disconnect_indication (void)
 *
 *    Disconnect request from other device
 *
 */
void irlap_disconnect_indication(struct irlap_cb *self, LAP_REASON reason)
{
        IRDA_DEBUG(1, "%s(), reason=%s\n", __FUNCTION__, lap_reasons[reason]);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        /* Flush queues */
        irlap_flush_all_queues(self);

        switch (reason) {
        case LAP_RESET_INDICATION:
                IRDA_DEBUG(1, "%s(), Sending reset request!\n", __FUNCTION__);
                irlap_do_event(self, RESET_REQUEST, NULL, NULL);
                break;
        case LAP_NO_RESPONSE:      /* FALLTROUGH */
        case LAP_DISC_INDICATION:  /* FALLTROUGH */
        case LAP_FOUND_NONE:       /* FALLTROUGH */
        case LAP_MEDIA_BUSY:
                irlmp_link_disconnect_indication(self->notify.instance, self,
                                                 reason, NULL);
                break;
        default:
                IRDA_ERROR("%s: Unknown reason %d\n", __FUNCTION__, reason);
        }
}

/*
 * Function irlap_discovery_request (gen_addr_bit)
 *
 *    Start one single discovery operation.
 *
 */
void irlap_discovery_request(struct irlap_cb *self, discovery_t *discovery)
{
        struct irlap_info info;

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
        IRDA_ASSERT(discovery != NULL, return;);

        IRDA_DEBUG(4, "%s(), nslots = %d\n", __FUNCTION__, discovery->nslots);

        IRDA_ASSERT((discovery->nslots == 1) || (discovery->nslots == 6) ||
                    (discovery->nslots == 8) || (discovery->nslots == 16),
                    return;);

        /* Discovery is only possible in NDM mode */
        if (self->state != LAP_NDM) {
                IRDA_DEBUG(4, "%s(), discovery only possible in NDM mode\n",
                           __FUNCTION__);
                irlap_discovery_confirm(self, NULL);
                /* Note : in theory, if we are not in NDM, we could postpone
                 * the discovery like we do for connection request.
                 * In practice, it's not worth it. If the media was busy,
                 * it's likely next time around it won't be busy. If we are
                 * in REPLY state, we will get passive discovery info & event.
                 * Jean II */
                return;
        }

        /* Check if last discovery request finished in time, or if
         * it was aborted due to the media busy flag. */
        if (self->discovery_log != NULL) {
                hashbin_delete(self->discovery_log, (FREE_FUNC) kfree);
                self->discovery_log = NULL;
        }

        /* All operations will occur at predictable time, no need to lock */
        self->discovery_log = hashbin_new(HB_NOLOCK);

        if (self->discovery_log == NULL) {
                IRDA_WARNING("%s(), Unable to allocate discovery log!\n",
                             __FUNCTION__);
                return;
        }

        info.S = discovery->nslots; /* Number of slots */
        info.s = 0; /* Current slot */

        self->discovery_cmd = discovery;
        info.discovery = discovery;

        /* sysctl_slot_timeout bounds are checked in irsysctl.c - Jean II */
        self->slot_timeout = sysctl_slot_timeout * HZ / 1000;

        irlap_do_event(self, DISCOVERY_REQUEST, NULL, &info);
}

/*
 * Function irlap_discovery_confirm (log)
 *
 *    A device has been discovered in front of this station, we
 *    report directly to LMP.
 */
void irlap_discovery_confirm(struct irlap_cb *self, hashbin_t *discovery_log)
{
        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        IRDA_ASSERT(self->notify.instance != NULL, return;);

        /*
         * Check for successful discovery, since we are then allowed to clear
         * the media busy condition (IrLAP 6.13.4 - p.94). This should allow
         * us to make connection attempts much faster and easier (i.e. no
         * collisions).
         * Setting media busy to false will also generate an event allowing
         * to process pending events in NDM state machine.
         * Note : the spec doesn't define what's a successful discovery is.
         * If we want Ultra to work, it's successful even if there is
         * nobody discovered - Jean II
         */
        if (discovery_log)
                irda_device_set_media_busy(self->netdev, FALSE);

        /* Inform IrLMP */
        irlmp_link_discovery_confirm(self->notify.instance, discovery_log);
}

/*
 * Function irlap_discovery_indication (log)
 *
 *    Somebody is trying to discover us!
 *
 */
void irlap_discovery_indication(struct irlap_cb *self, discovery_t *discovery)
{
        IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
        IRDA_ASSERT(discovery != NULL, return;);

        IRDA_ASSERT(self->notify.instance != NULL, return;);

        /* A device is very likely to connect immediately after it performs
         * a successful discovery. This means that in our case, we are much
         * more likely to receive a connection request over the medium.
         * So, we backoff to avoid collisions.
         * IrLAP spec 6.13.4 suggest 100ms...
         * Note : this little trick actually make a *BIG* difference. If I set
         * my Linux box with discovery enabled and one Ultra frame sent every
         * second, my Palm has no trouble connecting to it every time !
         * Jean II */
        irda_device_set_media_busy(self->netdev, SMALL);

        irlmp_link_discovery_indication(self->notify.instance, discovery);
}

/*
 * Function irlap_status_indication (quality_of_link)
 */
void irlap_status_indication(struct irlap_cb *self, int quality_of_link)
{
        switch (quality_of_link) {
        case STATUS_NO_ACTIVITY:
                IRDA_MESSAGE("IrLAP, no activity on link!\n");
                break;
        case STATUS_NOISY:
                IRDA_MESSAGE("IrLAP, noisy link!\n");
                break;
        default:
                break;
        }
        irlmp_status_indication(self->notify.instance,
                                quality_of_link, LOCK_NO_CHANGE);
}

/*
 * Function irlap_reset_indication (void)
 */
void irlap_reset_indication(struct irlap_cb *self)
{
        IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        if (self->state == LAP_RESET_WAIT)
                irlap_do_event(self, RESET_REQUEST, NULL, NULL);
        else
                irlap_do_event(self, RESET_RESPONSE, NULL, NULL);
}

/*
 * Function irlap_reset_confirm (void)
 */
void irlap_reset_confirm(void)
{
        IRDA_DEBUG(1, "%s()\n", __FUNCTION__);
}

/*
 * Function irlap_generate_rand_time_slot (S, s)
 *
 *    Generate a random time slot between s and S-1 where
 *    S = Number of slots (0 -> S-1)
 *    s = Current slot
 */
int irlap_generate_rand_time_slot(int S, int s)
{
        static int rand;
        int slot;

        IRDA_ASSERT((S - s) > 0, return 0;);

        rand += jiffies;
        rand ^= (rand << 12);
        rand ^= (rand >> 20);

        slot = s + rand % (S-s);

        IRDA_ASSERT((slot >= s) || (slot < S), return 0;);

        return slot;
}

/*
 * Function irlap_update_nr_received (nr)
 *
 *    Remove all acknowledged frames in current window queue. This code is
 *    not intuitive and you should not try to change it. If you think it
 *    contains bugs, please mail a patch to the author instead.
 */
void irlap_update_nr_received(struct irlap_cb *self, int nr)
{
        struct sk_buff *skb = NULL;
        int count = 0;

        /*
         * Remove all the ack-ed frames from the window queue.
         */

        /*
         *  Optimize for the common case. It is most likely that the receiver
         *  will acknowledge all the frames we have sent! So in that case we
         *  delete all frames stored in window.
         */
        if (nr == self->vs) {
                while ((skb = skb_dequeue(&self->wx_list)) != NULL) {
                        dev_kfree_skb(skb);
                }
                /* The last acked frame is the next to send minus one */
                self->va = nr - 1;
        } else {
                /* Remove all acknowledged frames in current window */
                while ((skb_peek(&self->wx_list) != NULL) &&
                       (((self->va+1) % 8) != nr))
                {
                        skb = skb_dequeue(&self->wx_list);
                        dev_kfree_skb(skb);

                        self->va = (self->va + 1) % 8;
                        count++;
                }
        }

        /* Advance window */
        self->window = self->window_size - skb_queue_len(&self->wx_list);
}

/*
 * Function irlap_validate_ns_received (ns)
 *
 *    Validate the next to send (ns) field from received frame.
 */
int irlap_validate_ns_received(struct irlap_cb *self, int ns)
{
        /*  ns as expected?  */
        if (ns == self->vr)
                return NS_EXPECTED;
        /*
         *  Stations are allowed to treat invalid NS as unexpected NS
         *  IrLAP, Recv ... with-invalid-Ns. p. 84
         */
        return NS_UNEXPECTED;

        /* return NR_INVALID; */
}
/*
 * Function irlap_validate_nr_received (nr)
 *
 *    Validate the next to receive (nr) field from received frame.
 *
 */
int irlap_validate_nr_received(struct irlap_cb *self, int nr)
{
        /*  nr as expected?  */
        if (nr == self->vs) {
                IRDA_DEBUG(4, "%s(), expected!\n", __FUNCTION__);
                return NR_EXPECTED;
        }

        /*
         *  unexpected nr? (but within current window), first we check if the
         *  ns numbers of the frames in the current window wrap.
         */
        if (self->va < self->vs) {
                if ((nr >= self->va) && (nr <= self->vs))
                        return NR_UNEXPECTED;
        } else {
                if ((nr >= self->va) || (nr <= self->vs))
                        return NR_UNEXPECTED;
        }

        /* Invalid nr!  */
        return NR_INVALID;
}

/*
 * Function irlap_initiate_connection_state ()
 *
 *    Initialize the connection state parameters
 *
 */
void irlap_initiate_connection_state(struct irlap_cb *self)
{
        IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        /* Next to send and next to receive */
        self->vs = self->vr = 0;

        /* Last frame which got acked (0 - 1) % 8 */
        self->va = 7;

        self->window = 1;

        self->remote_busy = FALSE;
        self->retry_count = 0;
}

/*
 * Function irlap_wait_min_turn_around (self, qos)
 *
 *    Wait negotiated minimum turn around time, this function actually sets
 *    the number of BOS's that must be sent before the next transmitted
 *    frame in order to delay for the specified amount of time. This is
 *    done to avoid using timers, and the forbidden udelay!
 */
void irlap_wait_min_turn_around(struct irlap_cb *self, struct qos_info *qos)
{
        __u32 min_turn_time;
        __u32 speed;

        /* Get QoS values.  */
        speed = qos->baud_rate.value;
        min_turn_time = qos->min_turn_time.value;

        /* No need to calculate XBOFs for speeds over 115200 bps */
        if (speed > 115200) {
                self->mtt_required = min_turn_time;
                return;
        }

        /*
         *  Send additional BOF's for the next frame for the requested
         *  min turn time, so now we must calculate how many chars (XBOF's) we
         *  must send for the requested time period (min turn time)
         */
        self->xbofs_delay = irlap_min_turn_time_in_bytes(speed, min_turn_time);
}

/*
 * Function irlap_flush_all_queues (void)
 *
 *    Flush all queues
 *
 */
void irlap_flush_all_queues(struct irlap_cb *self)
{
        struct sk_buff* skb;

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        /* Free transmission queue */
        while ((skb = skb_dequeue(&self->txq)) != NULL)
                dev_kfree_skb(skb);

        while ((skb = skb_dequeue(&self->txq_ultra)) != NULL)
                dev_kfree_skb(skb);

        /* Free sliding window buffered packets */
        while ((skb = skb_dequeue(&self->wx_list)) != NULL)
                dev_kfree_skb(skb);
}

/*
 * Function irlap_setspeed (self, speed)
 *
 *    Change the speed of the IrDA port
 *
 */
static void irlap_change_speed(struct irlap_cb *self, __u32 speed, int now)
{
        struct sk_buff *skb;

        IRDA_DEBUG(0, "%s(), setting speed to %d\n", __FUNCTION__, speed);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        self->speed = speed;

        /* Change speed now, or just piggyback speed on frames */
        if (now) {
                /* Send down empty frame to trigger speed change */
                skb = dev_alloc_skb(0);
                irlap_queue_xmit(self, skb);
        }
}

/*
 * Function irlap_init_qos_capabilities (self, qos)
 *
 *    Initialize QoS for this IrLAP session, What we do is to compute the
 *    intersection of the QoS capabilities for the user, driver and for
 *    IrLAP itself. Normally, IrLAP will not specify any values, but it can
 *    be used to restrict certain values.
 */
static void irlap_init_qos_capabilities(struct irlap_cb *self,
                                        struct qos_info *qos_user)
{
        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
        IRDA_ASSERT(self->netdev != NULL, return;);

        /* Start out with the maximum QoS support possible */
        irda_init_max_qos_capabilies(&self->qos_rx);

        /* Apply drivers QoS capabilities */
        irda_qos_compute_intersection(&self->qos_rx, self->qos_dev);

        /*
         *  Check for user supplied QoS parameters. The service user is only
         *  allowed to supply these values. We check each parameter since the
         *  user may not have set all of them.
         */
        if (qos_user) {
                IRDA_DEBUG(1, "%s(), Found user specified QoS!\n", __FUNCTION__);

                if (qos_user->baud_rate.bits)
                        self->qos_rx.baud_rate.bits &= qos_user->baud_rate.bits;

                if (qos_user->max_turn_time.bits)
                        self->qos_rx.max_turn_time.bits &= qos_user->max_turn_time.bits;
                if (qos_user->data_size.bits)
                        self->qos_rx.data_size.bits &= qos_user->data_size.bits;

                if (qos_user->link_disc_time.bits)
                        self->qos_rx.link_disc_time.bits &= qos_user->link_disc_time.bits;
        }

        /* Use 500ms in IrLAP for now */
        self->qos_rx.max_turn_time.bits &= 0x01;

        /* Set data size */
        /*self->qos_rx.data_size.bits &= 0x03;*/

        irda_qos_bits_to_value(&self->qos_rx);
}

/*
 * Function irlap_apply_default_connection_parameters (void, now)
 *
 *    Use the default connection and transmission parameters
 */
void irlap_apply_default_connection_parameters(struct irlap_cb *self)
{
        IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        /* xbofs : Default value in NDM */
        self->next_bofs   = 12;
        self->bofs_count  = 12;

        /* NDM Speed is 9600 */
        irlap_change_speed(self, 9600, TRUE);

        /* Set mbusy when going to NDM state */
        irda_device_set_media_busy(self->netdev, TRUE);

        /*
         * Generate random connection address for this session, which must
         * be 7 bits wide and different from 0x00 and 0xfe
         */
        while ((self->caddr == 0x00) || (self->caddr == 0xfe)) {
                get_random_bytes(&self->caddr, sizeof(self->caddr));
                self->caddr &= 0xfe;
        }

        /* Use default values until connection has been negitiated */
        self->slot_timeout = sysctl_slot_timeout;
        self->final_timeout = FINAL_TIMEOUT;
        self->poll_timeout = POLL_TIMEOUT;
        self->wd_timeout = WD_TIMEOUT;

        /* Set some default values */
        self->qos_tx.baud_rate.value = 9600;
        self->qos_rx.baud_rate.value = 9600;
        self->qos_tx.max_turn_time.value = 0;
        self->qos_rx.max_turn_time.value = 0;
        self->qos_tx.min_turn_time.value = 0;
        self->qos_rx.min_turn_time.value = 0;
        self->qos_tx.data_size.value = 64;
        self->qos_rx.data_size.value = 64;
        self->qos_tx.window_size.value = 1;
        self->qos_rx.window_size.value = 1;
        self->qos_tx.additional_bofs.value = 12;
        self->qos_rx.additional_bofs.value = 12;
        self->qos_tx.link_disc_time.value = 0;
        self->qos_rx.link_disc_time.value = 0;

        irlap_flush_all_queues(self);

        self->disconnect_pending = FALSE;
        self->connect_pending = FALSE;
}

/*
 * Function irlap_apply_connection_parameters (qos, now)
 *
 *    Initialize IrLAP with the negotiated QoS values
 *
 * If 'now' is false, the speed and xbofs will be changed after the next
 * frame is sent.
 * If 'now' is true, the speed and xbofs is changed immediately
 */
void irlap_apply_connection_parameters(struct irlap_cb *self, int now)
{
        IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

        /* Set the negotiated xbofs value */
        self->next_bofs   = self->qos_tx.additional_bofs.value;
        if (now)
                self->bofs_count = self->next_bofs;

        /* Set the negotiated link speed (may need the new xbofs value) */
        irlap_change_speed(self, self->qos_tx.baud_rate.value, now);

        self->window_size = self->qos_tx.window_size.value;
        self->window      = self->qos_tx.window_size.value;

#ifdef CONFIG_IRDA_DYNAMIC_WINDOW
        /*
         *  Calculate how many bytes it is possible to transmit before the
         *  link must be turned around
         */
        self->line_capacity =
                irlap_max_line_capacity(self->qos_tx.baud_rate.value,
                                        self->qos_tx.max_turn_time.value);
        self->bytes_left = self->line_capacity;
#endif /* CONFIG_IRDA_DYNAMIC_WINDOW */


        /*
         *  Initialize timeout values, some of the rules are listed on
         *  page 92 in IrLAP.
         */
        IRDA_ASSERT(self->qos_tx.max_turn_time.value != 0, return;);
        IRDA_ASSERT(self->qos_rx.max_turn_time.value != 0, return;);
        /* The poll timeout applies only to the primary station.
         * It defines the maximum time the primary stay in XMIT mode
         * before timeout and turning the link around (sending a RR).
         * Or, this is how much we can keep the pf bit in primary mode.
         * Therefore, it must be lower or equal than our *OWN* max turn around.
         * Jean II */
        self->poll_timeout = self->qos_tx.max_turn_time.value * HZ / 1000;
        /* The Final timeout applies only to the primary station.
         * It defines the maximum time the primary wait (mostly in RECV mode)
         * for an answer from the secondary station before polling it again.
         * Therefore, it must be greater or equal than our *PARTNER*
         * max turn around time - Jean II */
        self->final_timeout = self->qos_rx.max_turn_time.value * HZ / 1000;
        /* The Watchdog Bit timeout applies only to the secondary station.
         * It defines the maximum time the secondary wait (mostly in RECV mode)
         * for poll from the primary station before getting annoyed.
         * Therefore, it must be greater or equal than our *PARTNER*
         * max turn around time - Jean II */
        self->wd_timeout = self->final_timeout * 2;

        /*
         * N1 and N2 are maximum retry count for *both* the final timer
         * and the wd timer (with a factor 2) as defined above.
         * After N1 retry of a timer, we give a warning to the user.
         * After N2 retry, we consider the link dead and disconnect it.
         * Jean II
         */

        /*
         *  Set N1 to 0 if Link Disconnect/Threshold Time = 3 and set it to
         *  3 seconds otherwise. See page 71 in IrLAP for more details.
         *  Actually, it's not always 3 seconds, as we allow to set
         *  it via sysctl... Max maxtt is 500ms, and N1 need to be multiple
         *  of 2, so 1 second is minimum we can allow. - Jean II
         */
        if (self->qos_tx.link_disc_time.value == sysctl_warn_noreply_time)
                /*
                 * If we set N1 to 0, it will trigger immediately, which is
                 * not what we want. What we really want is to disable it,
                 * Jean II
                 */
                self->N1 = -2; /* Disable - Need to be multiple of 2*/
        else
                self->N1 = sysctl_warn_noreply_time * 1000 /
                  self->qos_rx.max_turn_time.value;

        IRDA_DEBUG(4, "Setting N1 = %d\n", self->N1);

        /* Set N2 to match our own disconnect time */
        self->N2 = self->qos_tx.link_disc_time.value * 1000 /
                self->qos_rx.max_turn_time.value;
        IRDA_DEBUG(4, "Setting N2 = %d\n", self->N2);
}

#ifdef CONFIG_PROC_FS
struct irlap_iter_state {
        int id;
};

static void *irlap_seq_start(struct seq_file *seq, loff_t *pos)
{
        struct irlap_iter_state *iter = seq->private;
        struct irlap_cb *self;

        /* Protect our access to the tsap list */
        spin_lock_irq(&irlap->hb_spinlock);
        iter->id = 0;

        for (self = (struct irlap_cb *) hashbin_get_first(irlap); 
             self; self = (struct irlap_cb *) hashbin_get_next(irlap)) {
                if (iter->id == *pos)
                        break;
                ++iter->id;
        }
                
        return self;
}

static void *irlap_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        struct irlap_iter_state *iter = seq->private;

        ++*pos;
        ++iter->id;
        return (void *) hashbin_get_next(irlap);
}

static void irlap_seq_stop(struct seq_file *seq, void *v)
{
        spin_unlock_irq(&irlap->hb_spinlock);
}

static int irlap_seq_show(struct seq_file *seq, void *v)
{
        const struct irlap_iter_state *iter = seq->private;
        const struct irlap_cb *self = v;
        
        IRDA_ASSERT(self->magic == LAP_MAGIC, return -EINVAL;);

        seq_printf(seq, "irlap%d ", iter->id);
        seq_printf(seq, "state: %s\n",
                   irlap_state[self->state]);

        seq_printf(seq, "  device name: %s, ",
                   (self->netdev) ? self->netdev->name : "bug");
        seq_printf(seq, "hardware name: %s\n", self->hw_name);

        seq_printf(seq, "  caddr: %#02x, ", self->caddr);
        seq_printf(seq, "saddr: %#08x, ", self->saddr);
        seq_printf(seq, "daddr: %#08x\n", self->daddr);

        seq_printf(seq, "  win size: %d, ",
                   self->window_size);
        seq_printf(seq, "win: %d, ", self->window);
#ifdef CONFIG_IRDA_DYNAMIC_WINDOW
        seq_printf(seq, "line capacity: %d, ",
                   self->line_capacity);
        seq_printf(seq, "bytes left: %d\n", self->bytes_left);
#endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
        seq_printf(seq, "  tx queue len: %d ",
                   skb_queue_len(&self->txq));
        seq_printf(seq, "win queue len: %d ",
                   skb_queue_len(&self->wx_list));
        seq_printf(seq, "rbusy: %s", self->remote_busy ?
                   "TRUE" : "FALSE");
        seq_printf(seq, " mbusy: %s\n", self->media_busy ?
                   "TRUE" : "FALSE");

        seq_printf(seq, "  retrans: %d ", self->retry_count);
        seq_printf(seq, "vs: %d ", self->vs);
        seq_printf(seq, "vr: %d ", self->vr);
        seq_printf(seq, "va: %d\n", self->va);

        seq_printf(seq, "  qos\tbps\tmaxtt\tdsize\twinsize\taddbofs\tmintt\tldisc\tcomp\n");

        seq_printf(seq, "  tx\t%d\t",
                   self->qos_tx.baud_rate.value);
        seq_printf(seq, "%d\t",
                   self->qos_tx.max_turn_time.value);
        seq_printf(seq, "%d\t",
                   self->qos_tx.data_size.value);
        seq_printf(seq, "%d\t",
                   self->qos_tx.window_size.value);
        seq_printf(seq, "%d\t",
                   self->qos_tx.additional_bofs.value);
        seq_printf(seq, "%d\t",
                   self->qos_tx.min_turn_time.value);
        seq_printf(seq, "%d\t",
                   self->qos_tx.link_disc_time.value);
        seq_printf(seq, "\n");

        seq_printf(seq, "  rx\t%d\t",
                   self->qos_rx.baud_rate.value);
        seq_printf(seq, "%d\t",
                   self->qos_rx.max_turn_time.value);
        seq_printf(seq, "%d\t",
                   self->qos_rx.data_size.value);
        seq_printf(seq, "%d\t",
                   self->qos_rx.window_size.value);
        seq_printf(seq, "%d\t",
                   self->qos_rx.additional_bofs.value);
        seq_printf(seq, "%d\t",
                   self->qos_rx.min_turn_time.value);
        seq_printf(seq, "%d\n",
                   self->qos_rx.link_disc_time.value);

        return 0;
}

static struct seq_operations irlap_seq_ops = {
        .start  = irlap_seq_start,
        .next   = irlap_seq_next,
        .stop   = irlap_seq_stop,
        .show   = irlap_seq_show,
};

static int irlap_seq_open(struct inode *inode, struct file *file)
{
        struct seq_file *seq;
        int rc = -ENOMEM;
        struct irlap_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
       
        if (!s)
                goto out;

        if (irlap == NULL) {
                rc = -EINVAL;
                goto out_kfree;
        }

        rc = seq_open(file, &irlap_seq_ops);
        if (rc)
                goto out_kfree;

        seq          = file->private_data;
        seq->private = s;
        memset(s, 0, sizeof(*s));
out:
        return rc;
out_kfree:
        kfree(s);
        goto out;
}

struct file_operations irlap_seq_fops = {
        .owner          = THIS_MODULE,
        .open           = irlap_seq_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release_private,
};

#endif /* CONFIG_PROC_FS */