irttp.c

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/*********************************************************************
 *                
 * Filename:      irttp.c
 * Version:       1.2
 * Description:   Tiny Transport Protocol (TTP) implementation
 * Status:        Stable
 * Author:        Dag Brattli <dagb@cs.uit.no>
 * Created at:    Sun Aug 31 20:14:31 1997
 * Modified at:   Sun Jan 30 14:30:32 2000
 * Modified by:   Dag Brattli <dagb@cs.uit.no>
 * 
 *     Copyright (c) 1998-2000 Dag Brattli <dagb@cs.uit.no>, 
 *     All Rights Reserved.
 *     
 *     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.
 *
 *     Neither Dag Brattli nor University of Tromsø admit liability nor
 *     provide warranty for any of this software. This material is 
 *     provided "AS-IS" and at no charge.
 *
 ********************************************************************/

#include <linux/config.h>
#include <linux/skbuff.h>
#include <linux/init.h>

#include <asm/byteorder.h>
#include <asm/unaligned.h>

#include <net/irda/irda.h>
#include <net/irda/irmod.h>
#include <net/irda/irlap.h>
#include <net/irda/irlmp.h>
#include <net/irda/parameters.h>
#include <net/irda/irttp.h>

static struct irttp_cb *irttp = NULL;

static void __irttp_close_tsap(struct tsap_cb *self);

static int irttp_data_indication(void *instance, void *sap, 
                                 struct sk_buff *skb);
static int irttp_udata_indication(void *instance, void *sap, 
                                  struct sk_buff *skb);
static void irttp_disconnect_indication(void *instance, void *sap,  
                                        LM_REASON reason, struct sk_buff *);
static void irttp_connect_indication(void *instance, void *sap, 
                                     struct qos_info *qos, __u32 max_sdu_size,
                                     __u8 header_size, struct sk_buff *skb);
static void irttp_connect_confirm(void *instance, void *sap, 
                                  struct qos_info *qos, __u32 max_sdu_size, 
                                  __u8 header_size, struct sk_buff *skb);
static void irttp_run_tx_queue(struct tsap_cb *self);
static void irttp_run_rx_queue(struct tsap_cb *self);

static void irttp_flush_queues(struct tsap_cb *self);
static void irttp_fragment_skb(struct tsap_cb *self, struct sk_buff *skb);
static void irttp_start_todo_timer(struct tsap_cb *self, int timeout);
static struct sk_buff *irttp_reassemble_skb(struct tsap_cb *self);
static int irttp_param_max_sdu_size(void *instance, irda_param_t *param, 
                                    int get);

/* Information for parsing parameters in IrTTP */
static pi_minor_info_t pi_minor_call_table[] = {
        { NULL, 0 },                                             /* 0x00 */
        { irttp_param_max_sdu_size, PV_INTEGER | PV_BIG_ENDIAN } /* 0x01 */
};
static pi_major_info_t pi_major_call_table[] = {{ pi_minor_call_table, 2 }};
static pi_param_info_t param_info = { pi_major_call_table, 1, 0x0f, 4 };

/*
 * Function irttp_init (void)
 *
 *    Initialize the IrTTP layer. Called by module initialization code
 *
 */
int __init irttp_init(void)
{
        /* Initialize the irttp structure. */
        if (irttp == NULL) {
                irttp = kmalloc(sizeof(struct irttp_cb), GFP_KERNEL);
                if (irttp == NULL)
                        return -ENOMEM;
        }
        memset(irttp, 0, sizeof(struct irttp_cb));
        
        irttp->magic = TTP_MAGIC;

        irttp->tsaps = hashbin_new(HB_LOCAL);
        if (!irttp->tsaps) {
                ERROR(__FUNCTION__ "(), can't allocate IrTTP hashbin!\n");
                return -ENOMEM;
        }
        
        return 0;
}

/*
 * Function irttp_cleanup (void)
 *
 *    Called by module destruction/cleanup code
 *
 */
#ifdef MODULE
void irttp_cleanup(void) 
{
        /* Check for main structure */
        ASSERT(irttp != NULL, return;);
        ASSERT(irttp->magic == TTP_MAGIC, return;);
        
        /*
         *  Delete hashbin and close all TSAP instances in it
         */
        hashbin_delete(irttp->tsaps, (FREE_FUNC) __irttp_close_tsap);

        irttp->magic = 0;
        
        /* De-allocate main structure */
        kfree(irttp);

        irttp = NULL;
}
#endif

/*
 * Function irttp_open_tsap (stsap, notify)
 *
 *    Create TSAP connection endpoint,
 */
struct tsap_cb *irttp_open_tsap(__u8 stsap_sel, int credit, notify_t *notify) 
{
        struct tsap_cb *self;
        struct lsap_cb *lsap;
        notify_t ttp_notify;

        ASSERT(irttp != NULL, return NULL;);
        ASSERT(irttp->magic == TTP_MAGIC, return NULL;);

        self = kmalloc(sizeof(struct tsap_cb), GFP_ATOMIC);
        if (self == NULL) {
                IRDA_DEBUG(0, __FUNCTION__ "(), unable to kmalloc!\n");
                return NULL;
        }
        memset(self, 0, sizeof(struct tsap_cb));
        spin_lock_init(&self->lock);

        init_timer(&self->todo_timer);

        /* Initialize callbacks for IrLMP to use */
        irda_notify_init(&ttp_notify);
        ttp_notify.connect_confirm = irttp_connect_confirm;
        ttp_notify.connect_indication = irttp_connect_indication;
        ttp_notify.disconnect_indication = irttp_disconnect_indication;
        ttp_notify.data_indication = irttp_data_indication;
        ttp_notify.udata_indication = irttp_udata_indication;
        ttp_notify.instance = self;
        strncpy(ttp_notify.name, notify->name, NOTIFY_MAX_NAME);

        self->magic = TTP_TSAP_MAGIC;
        self->connected = FALSE;

        skb_queue_head_init(&self->rx_queue);
        skb_queue_head_init(&self->tx_queue);
        skb_queue_head_init(&self->rx_fragments);
        /*
         *  Create LSAP at IrLMP layer
         */
        lsap = irlmp_open_lsap(stsap_sel, &ttp_notify, 0);
        if (lsap == NULL) {
                WARNING(__FUNCTION__ "(), unable to allocate LSAP!!\n");
                return NULL;
        }
        
        /*
         *  If user specified LSAP_ANY as source TSAP selector, then IrLMP
         *  will replace it with whatever source selector which is free, so
         *  the stsap_sel we have might not be valid anymore
         */
        self->stsap_sel = lsap->slsap_sel;
        IRDA_DEBUG(4, __FUNCTION__ "(), stsap_sel=%02x\n", self->stsap_sel);

        self->notify = *notify;
        self->lsap = lsap;

        hashbin_insert(irttp->tsaps, (queue_t *) self, (int) self, NULL);

        if (credit > TTP_MAX_QUEUE)
                self->initial_credit = TTP_MAX_QUEUE;
        else
                self->initial_credit = credit;

        return self;    
}

/*
 * Function irttp_close (handle)
 *
 *    Remove an instance of a TSAP. This function should only deal with the
 *    deallocation of the TSAP, and resetting of the TSAPs values;
 *
 */
static void __irttp_close_tsap(struct tsap_cb *self)
{
        /* First make sure we're connected. */
        ASSERT(self != NULL, return;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return;);

        irttp_flush_queues(self);

        del_timer(&self->todo_timer);

        self->connected = FALSE;
        self->magic = ~TTP_TSAP_MAGIC;

        kfree(self);
}

/*
 * Function irttp_close (self)
 *
 *    Remove TSAP from list of all TSAPs and then deallocate all resources
 *    associated with this TSAP
 *
 */
int irttp_close_tsap(struct tsap_cb *self)
{
        struct tsap_cb *tsap;

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

        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);

        /* Make sure tsap has been disconnected */
        if (self->connected) {
                /* Check if disconnect is not pending */
                if (!self->disconnect_pend) {
                        IRDA_DEBUG(0, __FUNCTION__ "(), TSAP still connected!\n");
                        irttp_disconnect_request(self, NULL, P_NORMAL);
                }
                self->close_pend = TRUE;
                irttp_start_todo_timer(self, 1*HZ);

                return 0; /* Will be back! */
        }
        
        tsap = hashbin_remove(irttp->tsaps, (int) self, NULL);

        ASSERT(tsap == self, return -1;);

        /* Close corresponding LSAP */
        if (self->lsap) {
                irlmp_close_lsap(self->lsap);
                self->lsap = NULL;
        }

        __irttp_close_tsap(self);

        return 0;
}

/*
 * Function irttp_udata_request (self, skb)
 *
 *    Send unreliable data on this TSAP
 *
 */
int irttp_udata_request(struct tsap_cb *self, struct sk_buff *skb) 
{
        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
        ASSERT(skb != NULL, return -1;);

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

        /* Check that nothing bad happens */
        if ((skb->len == 0) || (!self->connected)) {
                IRDA_DEBUG(1, __FUNCTION__ "(), No data, or not connected\n");
                return -1;
        }
        
        if (skb->len > self->max_seg_size) {
                IRDA_DEBUG(1, __FUNCTION__ "(), UData is to large for IrLAP!\n");
                return -1;
        }
                    
        irlmp_udata_request(self->lsap, skb);
        self->stats.tx_packets++;

        return 0;
}

/*
 * Function irttp_data_request (handle, skb)
 *
 *    Queue frame for transmission. If SAR is enabled, fragement the frame 
 *    and queue the fragments for transmission
 */
int irttp_data_request(struct tsap_cb *self, struct sk_buff *skb) 
{
        __u8 *frame;

        /* Check that nothing bad happens */
        if ((skb->len == 0) || (!self->connected)) {
                WARNING(__FUNCTION__ "(), No data, or not connected\n");
                return -ENOTCONN;
        }

        /*  
         *  Check if SAR is disabled, and the frame is larger than what fits
         *  inside an IrLAP frame
         */
        if ((self->tx_max_sdu_size == 0) && (skb->len > self->max_seg_size)) {
                ERROR(__FUNCTION__ 
                      "(), SAR disabled, and data is to large for IrLAP!\n");
                return -EMSGSIZE;
        }

        /* 
         *  Check if SAR is enabled, and the frame is larger than the 
         *  TxMaxSduSize 
         */
        if ((self->tx_max_sdu_size != 0) && 
            (self->tx_max_sdu_size != TTP_SAR_UNBOUND) && 
            (skb->len > self->tx_max_sdu_size))
        {
                ERROR(__FUNCTION__ "(), SAR enabled, "
                      "but data is larger than TxMaxSduSize!\n");
                return -EMSGSIZE;
        }
        /* 
         *  Check if transmit queue is full
         */
        if (skb_queue_len(&self->tx_queue) >= TTP_MAX_QUEUE) {
                /*
                 *  Give it a chance to empty itself
                 */
                irttp_run_tx_queue(self);
                
                return -ENOBUFS;
        }
       
        /* Queue frame, or queue frame segments */
        if ((self->tx_max_sdu_size == 0) || (skb->len < self->max_seg_size)) {
                /* Queue frame */
                ASSERT(skb_headroom(skb) >= TTP_HEADER, return -1;);
                frame = skb_push(skb, TTP_HEADER);
                frame[0] = 0x00; /* Clear more bit */
                
                skb_queue_tail(&self->tx_queue, skb);
        } else {
                /*
                 *  Fragment the frame, this function will also queue the
                 *  fragments, we don't care about the fact the the transmit
                 *  queue may be overfilled by all the segments for a little
                 *  while
                 */
                irttp_fragment_skb(self, skb);
        }

        /* Check if we can accept more data from client */
        if ((!self->tx_sdu_busy) && 
            (skb_queue_len(&self->tx_queue) > TTP_HIGH_THRESHOLD)) {
                
                /* Tx queue filling up, so stop client */
                self->tx_sdu_busy = TRUE;
                
                if (self->notify.flow_indication) {
                        self->notify.flow_indication(self->notify.instance, 
                                                     self, FLOW_STOP);
                }
        }
        
        /* Try to make some progress */
        irttp_run_tx_queue(self);
        
        return 0;
}

/*
 * Function irttp_run_tx_queue (self)
 *
 *    Transmit packets queued for transmission (if possible)
 *
 */
static void irttp_run_tx_queue(struct tsap_cb *self) 
{
        struct sk_buff *skb;
        unsigned long flags;
        int n;

        if (irda_lock(&self->tx_queue_lock) == FALSE)
                return;

        /* Try to send out frames as long as we have credits */
        while ((self->send_credit > 0) &&
               (skb = skb_dequeue(&self->tx_queue)))
        {
                /* 
                 * Make sure we don't flood IrLAP with frames just because
                 * the remote device has given us a lot of credits
                 */
                if (irlmp_get_lap_tx_queue_len(self->lsap) > LAP_MAX_QUEUE) {
                        /* Re-queue packet */
                        skb_queue_head(&self->tx_queue, skb);

                        /* Try later. Maybe IrLAP could notify us? */
                        irttp_start_todo_timer(self, MSECS_TO_JIFFIES(10));
                        
                        break;
                }

                /*
                 *  Since we can transmit and receive frames concurrently, 
                 *  the code below is a critical region and we must assure that
                 *  nobody messes with the credits while we update them.
                 */
                spin_lock_irqsave(&self->lock, flags);

                n = self->avail_credit;
                self->avail_credit = 0;
                
                /* Only room for 127 credits in frame */
                if (n > 127) {
                        self->avail_credit = n-127;
                        n = 127;
                }
                self->remote_credit += n;
                self->send_credit--;

                spin_unlock_irqrestore(&self->lock, flags);

                /* 
                 *  More bit must be set by the data_request() or fragment() 
                 *  functions
                 */
                skb->data[0] |= (n & 0x7f);
                
                irlmp_data_request(self->lsap, skb);
                self->stats.tx_packets++;

                /* Check if we can accept more frames from client */
                if ((self->tx_sdu_busy) && 
                    (skb_queue_len(&self->tx_queue) < TTP_LOW_THRESHOLD)) 
                {
                        self->tx_sdu_busy = FALSE;
                        
                        if (self->notify.flow_indication)
                                self->notify.flow_indication(
                                        self->notify.instance, self,
                                        FLOW_START);
                }
        }
        self->tx_queue_lock = 0; /* Reset lock */
}

/*
 * Function irttp_give_credit (self)
 *
 *    Send a dataless flowdata TTP-PDU and give available credit to peer
 *    TSAP
 */
void irttp_give_credit(struct tsap_cb *self) 
{
        struct sk_buff *tx_skb = NULL;
        unsigned long flags;
        int n;

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return;); 

        IRDA_DEBUG(4, __FUNCTION__ "() send=%d,avail=%d,remote=%d\n", 
                   self->send_credit, self->avail_credit, self->remote_credit);
        
        /* Give credit to peer */
        tx_skb = dev_alloc_skb(64);
        if (!tx_skb)
                return;

        /* Reserve space for LMP, and LAP header */
        skb_reserve(tx_skb, self->max_header_size);

        /*
         *  Since we can transmit and receive frames concurrently, 
         *  the code below is a critical region and we must assure that
         *  nobody messes with the credits while we update them.
         */
        spin_lock_irqsave(&self->lock, flags);

        n = self->avail_credit;
        self->avail_credit = 0;
        
        /* Only space for 127 credits in frame */
        if (n > 127) {
                self->avail_credit = n - 127;
                n = 127;
        }
        self->remote_credit += n;

        spin_unlock_irqrestore(&self->lock, flags);

        skb_put(tx_skb, 1);
        tx_skb->data[0] = (__u8) (n & 0x7f);
        
        irlmp_data_request(self->lsap, tx_skb);
        self->stats.tx_packets++;
}

/*
 * Function irttp_udata_indication (instance, sap, skb)
 *
 *    Received some unit-data (unreliable)
 *
 */
static int irttp_udata_indication(void *instance, void *sap, 
                                  struct sk_buff *skb) 
{
        struct tsap_cb *self;

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

        self = (struct tsap_cb *) instance;

        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
        ASSERT(skb != NULL, return -1;);

        /* Just pass data to layer above */
        if (self->notify.udata_indication)
                self->notify.udata_indication(self->notify.instance, self,skb);
        else
                dev_kfree_skb(skb);

        self->stats.rx_packets++;

        return 0;
}

/*
 * Function irttp_data_indication (instance, sap, skb)
 *
 *    Receive segment from IrLMP. 
 *
 */
static int irttp_data_indication(void *instance, void *sap, 
                                 struct sk_buff *skb)
{
        struct tsap_cb *self;
        int n;

        self = (struct tsap_cb *) instance;

        n = skb->data[0] & 0x7f;     /* Extract the credits */

        self->stats.rx_packets++;

        /* 
         *  Data or dataless packet? Dataless frames contains only the 
         *  TTP_HEADER. 
         */
        if (skb->len > 1) {
                /* Deal with inbound credit */
                self->send_credit += n;
                self->remote_credit--;
                
                /* 
                 *  We don't remove the TTP header, since we must preserve the
                 *  more bit, so the defragment routing knows what to do
                 */
                skb_queue_tail(&self->rx_queue, skb);
        } else {
                self->send_credit += n; /* Dataless flowdata TTP-PDU */
                dev_kfree_skb(skb);
        }

        irttp_run_rx_queue(self);

        /* 
         *  Give avay some credits to peer? 
         */
        if ((skb_queue_empty(&self->tx_queue)) && 
            (self->remote_credit < TTP_LOW_THRESHOLD) && 
            (self->avail_credit > 0)) 
        {
                /* Schedule to start immediately after this thread */
                irttp_start_todo_timer(self, 0);
                /*irttp_give_credit(self);*/
        }
        
        /* 
         * If the peer device has given us some credits and we didn't have
         * anyone from before, the we need to shedule the tx queue?  
         */
        if (self->send_credit == n) {
                /*irttp_run_tx_queue(self);*/
                irttp_start_todo_timer(self, 0);
        }
        return 0;
}

/*
 * Function irttp_flow_request (self, command)
 *
 *    This funtion could be used by the upper layers to tell IrTTP to stop
 *    delivering frames if the receive queues are starting to get full, or 
 *    to tell IrTTP to start delivering frames again.
 */
void irttp_flow_request(struct tsap_cb *self, LOCAL_FLOW flow)
{
        IRDA_DEBUG(1, __FUNCTION__ "()\n");

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return;);

        switch (flow) {
        case FLOW_STOP:
                IRDA_DEBUG(1, __FUNCTION__ "(), flow stop\n");
                self->rx_sdu_busy = TRUE;
                break;
        case FLOW_START:
                IRDA_DEBUG(1, __FUNCTION__ "(), flow start\n");
                self->rx_sdu_busy = FALSE;
                
                irttp_run_rx_queue(self);
                break;
        default:
                IRDA_DEBUG(1, __FUNCTION__ "(), Unknown flow command!\n");
        }
}
        
/*
 * Function irttp_connect_request (self, dtsap_sel, daddr, qos)
 *
 *    Try to connect to remote destination TSAP selector
 *
 */
int irttp_connect_request(struct tsap_cb *self, __u8 dtsap_sel, 
                          __u32 saddr, __u32 daddr,
                          struct qos_info *qos, __u32 max_sdu_size, 
                          struct sk_buff *userdata) 
{
        struct sk_buff *skb;
        __u8 *frame;
        __u8 n;
        
        IRDA_DEBUG(4, __FUNCTION__ "(), max_sdu_size=%d\n", max_sdu_size); 
        
        ASSERT(self != NULL, return -EBADR;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return -EBADR;);

        if (self->connected)
                return -EISCONN;
        
        /* Any userdata supplied? */
        if (userdata == NULL) {
                skb = dev_alloc_skb(64);
                if (!skb) 
                        return -ENOMEM;
                
                /* Reserve space for MUX_CONTROL and LAP header */
                skb_reserve(skb, TTP_MAX_HEADER);
        } else {
                skb = userdata;
                /*  
                 *  Check that the client has reserved enough space for 
                 *  headers
                 */
                ASSERT(skb_headroom(userdata) >= TTP_MAX_HEADER, return -1;);
        }

        /* Initialize connection parameters */
        self->connected = FALSE;
        self->avail_credit = 0;
        self->rx_max_sdu_size = max_sdu_size;
        self->rx_sdu_size = 0;
        self->rx_sdu_busy = FALSE;
        self->dtsap_sel = dtsap_sel;

        n = self->initial_credit;

        self->remote_credit = 0;
        self->send_credit = 0;
        
        /*
         *  Give away max 127 credits for now
         */
        if (n > 127) {
                self->avail_credit=n-127;
                n = 127;
        }

        self->remote_credit = n;

        /* SAR enabled? */
        if (max_sdu_size > 0) {
                ASSERT(skb_headroom(skb) >= (TTP_MAX_HEADER + TTP_SAR_HEADER), 
                       return -1;);

                /* Insert SAR parameters */
                frame = skb_push(skb, TTP_HEADER+TTP_SAR_HEADER);
                
                frame[0] = TTP_PARAMETERS | n; 
                frame[1] = 0x04; /* Length */
                frame[2] = 0x01; /* MaxSduSize */
                frame[3] = 0x02; /* Value length */

                put_unaligned(cpu_to_be16((__u16) max_sdu_size), 
                              (__u16 *)(frame+4));
        } else {
                /* Insert plain TTP header */
                frame = skb_push(skb, TTP_HEADER);
                
                /* Insert initial credit in frame */
                frame[0] = n & 0x7f;
        }

        /* Connect with IrLMP. No QoS parameters for now */
        return irlmp_connect_request(self->lsap, dtsap_sel, saddr, daddr, qos, 
                                     skb);
}

/*
 * Function irttp_connect_confirm (handle, qos, skb)
 *
 *    Sevice user confirms TSAP connection with peer. 
 *
 */
static void irttp_connect_confirm(void *instance, void *sap, 
                                  struct qos_info *qos, __u32 max_seg_size,
                                  __u8 max_header_size, struct sk_buff *skb) 
{
        struct tsap_cb *self;
        int parameters;
        int ret;
        __u8 plen;
        __u8 n;

        IRDA_DEBUG(4, __FUNCTION__ "()\n");
        
        self = (struct tsap_cb *) instance;

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
        ASSERT(skb != NULL, return;);

        self->max_seg_size = max_seg_size - TTP_HEADER;
        self->max_header_size = max_header_size + TTP_HEADER;

        /*
         *  Check if we have got some QoS parameters back! This should be the
         *  negotiated QoS for the link.
         */
        if (qos) {
                IRDA_DEBUG(4, "IrTTP, Negotiated BAUD_RATE: %02x\n", 
                       qos->baud_rate.bits);                    
                IRDA_DEBUG(4, "IrTTP, Negotiated BAUD_RATE: %d bps.\n", 
                       qos->baud_rate.value);
        }

        n = skb->data[0] & 0x7f;
        
        IRDA_DEBUG(4, __FUNCTION__ "(), Initial send_credit=%d\n", n);
        
        self->send_credit = n;
        self->tx_max_sdu_size = 0;
        self->connected = TRUE;

        parameters = skb->data[0] & 0x80;       

        ASSERT(skb->len >= TTP_HEADER, return;);
        skb_pull(skb, TTP_HEADER);

        if (parameters) {
                plen = skb->data[0];

                ret = irda_param_extract_all(self, skb->data+1,
                                             IRDA_MIN(skb->len-1, plen), 
                                             &param_info);

                /* Any errors in the parameter list? */
                if (ret < 0) {
                        WARNING(__FUNCTION__ 
                                "(), error extracting parameters\n");
                        dev_kfree_skb(skb);

                        /* Do not accept this connection attempt */
                        return;
                }
                /* Remove parameters */
                skb_pull(skb, IRDA_MIN(skb->len, plen+1));
        }
        
        IRDA_DEBUG(4, __FUNCTION__ "() send=%d,avail=%d,remote=%d\n", 
              self->send_credit, self->avail_credit, self->remote_credit);

        IRDA_DEBUG(2, __FUNCTION__ "(), MaxSduSize=%d\n", self->tx_max_sdu_size);

        if (self->notify.connect_confirm) {
                self->notify.connect_confirm(self->notify.instance, self, qos,
                                             self->tx_max_sdu_size,
                                             self->max_header_size, skb);
        }
}

/*
 * Function irttp_connect_indication (handle, skb)
 *
 *    Some other device is connecting to this TSAP
 *
 */
void irttp_connect_indication(void *instance, void *sap, struct qos_info *qos,
                              __u32 max_seg_size, __u8 max_header_size, 
                              struct sk_buff *skb) 
{
        struct tsap_cb *self;
        struct lsap_cb *lsap;
        int parameters;
        int ret;
        __u8 plen;
        __u8 n;

        self = (struct tsap_cb *) instance;

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
        ASSERT(skb != NULL, return;);

        lsap = (struct lsap_cb *) sap;

        self->max_seg_size = max_seg_size - TTP_HEADER;;
        self->max_header_size = max_header_size+TTP_HEADER;

        IRDA_DEBUG(4, __FUNCTION__ "(), TSAP sel=%02x\n", self->stsap_sel);

        /* Need to update dtsap_sel if its equal to LSAP_ANY */
        self->dtsap_sel = lsap->dlsap_sel;

        n = skb->data[0] & 0x7f;

        self->send_credit = n;
        self->tx_max_sdu_size = 0;
        
        parameters = skb->data[0] & 0x80;

        ASSERT(skb->len >= TTP_HEADER, return;);
        skb_pull(skb, TTP_HEADER);

        if (parameters) {
                plen = skb->data[0];
                
                ret = irda_param_extract_all(self, skb->data+1,
                                             IRDA_MIN(skb->len-1, plen), 
                                             &param_info);

                /* Any errors in the parameter list? */
                if (ret < 0) {
                        WARNING(__FUNCTION__ 
                                "(), error extracting parameters\n");
                        dev_kfree_skb(skb);
                        
                        /* Do not accept this connection attempt */
                        return;
                }

                /* Remove parameters */
                skb_pull(skb, IRDA_MIN(skb->len, plen+1));
        }

        if (self->notify.connect_indication) {
                self->notify.connect_indication(self->notify.instance, self, 
                                                qos, self->tx_max_sdu_size, 
                                                self->max_header_size, skb);
        } else
                dev_kfree_skb(skb);
}

/*
 * Function irttp_connect_response (handle, userdata)
 *
 *    Service user is accepting the connection, just pass it down to
 *    IrLMP!
 * 
 */
int irttp_connect_response(struct tsap_cb *self, __u32 max_sdu_size, 
                           struct sk_buff *userdata)
{
        struct sk_buff *skb;
        __u8 *frame;
        int ret;
        __u8 n;

        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);

        IRDA_DEBUG(4, __FUNCTION__ "(), Source TSAP selector=%02x\n", 
                   self->stsap_sel);
        
        /* Any userdata supplied? */
        if (userdata == NULL) {
                skb = dev_alloc_skb(64);
                if (!skb)
                        return -ENOMEM;

                /* Reserve space for MUX_CONTROL and LAP header */
                skb_reserve(skb, TTP_MAX_HEADER);
        } else {
                skb = userdata;
                /*  
                 *  Check that the client has reserved enough space for 
                 *  headers
                 */
                ASSERT(skb_headroom(skb) >= TTP_MAX_HEADER, return -1;);
        }
        
        self->avail_credit = 0;
        self->remote_credit = 0;
        self->rx_max_sdu_size = max_sdu_size;
        self->rx_sdu_size = 0;
        self->rx_sdu_busy = FALSE;

        n = self->initial_credit;

        /* Frame has only space for max 127 credits (7 bits) */
        if (n > 127) {
                self->avail_credit = n - 127;
                n = 127;
        }

        self->remote_credit = n;
        self->connected = TRUE;

        /* SAR enabled? */
        if (max_sdu_size > 0) {
                ASSERT(skb_headroom(skb) >= (TTP_MAX_HEADER+TTP_SAR_HEADER), 
                       return -1;);
                
                /* Insert TTP header with SAR parameters */
                frame = skb_push(skb, TTP_HEADER+TTP_SAR_HEADER);
                
                frame[0] = TTP_PARAMETERS | n;
                frame[1] = 0x04; /* Length */

                /* irda_param_insert(self, IRTTP_MAX_SDU_SIZE, frame+1,  */
/*                                TTP_SAR_HEADER, &param_info) */
                
                frame[2] = 0x01; /* MaxSduSize */
                frame[3] = 0x02; /* Value length */

                put_unaligned(cpu_to_be16((__u16) max_sdu_size), 
                              (__u16 *)(frame+4));
        } else {
                /* Insert TTP header */
                frame = skb_push(skb, TTP_HEADER);
                
                frame[0] = n & 0x7f;
        }
         
        ret = irlmp_connect_response(self->lsap, skb);

        return ret;
}

/*
 * Function irttp_dup (self, instance)
 *
 *    Duplicate TSAP, can be used by servers to confirm a connection on a
 *    new TSAP so it can keep listening on the old one.
 */
struct tsap_cb *irttp_dup(struct tsap_cb *orig, void *instance) 
{
        struct tsap_cb *new;

        IRDA_DEBUG(1, __FUNCTION__ "()\n");

        if (!hashbin_find(irttp->tsaps, (int) orig, NULL)) {
                IRDA_DEBUG(0, __FUNCTION__ "(), unable to find TSAP\n");
                return NULL;
        }
        new = kmalloc(sizeof(struct tsap_cb), GFP_ATOMIC);
        if (!new) {
                IRDA_DEBUG(0, __FUNCTION__ "(), unable to kmalloc\n");
                return NULL;
        }
        /* Dup */
        memcpy(new, orig, sizeof(struct tsap_cb));
        new->notify.instance = instance;
        new->lsap = irlmp_dup(orig->lsap, new);

        /* Not everything should be copied */
        init_timer(&new->todo_timer);

        skb_queue_head_init(&new->rx_queue);
        skb_queue_head_init(&new->tx_queue);
        skb_queue_head_init(&new->rx_fragments);

        hashbin_insert(irttp->tsaps, (queue_t *) new, (int) new, NULL);

        return new;
}

/*
 * Function irttp_disconnect_request (self)
 *
 *    Close this connection please! If priority is high, the queued data 
 *    segments, if any, will be deallocated first
 *
 */
int irttp_disconnect_request(struct tsap_cb *self, struct sk_buff *userdata, 
                             int priority)
{
        struct sk_buff *skb;
        int ret;

        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);

        /* Already disconnected? */
        if (!self->connected) {
                IRDA_DEBUG(4, __FUNCTION__ "(), already disconnected!\n");
                return -1;
        }

        /* Disconnect already pending? */
        if (self->disconnect_pend) {
                IRDA_DEBUG(1, __FUNCTION__ "(), disconnect already pending\n");
                if (userdata) {
                        dev_kfree_skb(userdata);
                }

                /* Try to make some progress */
                irttp_run_rx_queue(self);
                return -1;
        }

        /*
         *  Check if there is still data segments in the transmit queue
         */
        if (skb_queue_len(&self->tx_queue) > 0) {
                if (priority == P_HIGH) {
                        IRDA_DEBUG(1, __FUNCTION__  "High priority!!()\n" );
                        
                        /* 
                         *  No need to send the queued data, if we are 
                         *  disconnecting right now since the data will
                         *  not have any usable connection to be sent on
                         */
                        irttp_flush_queues(self);
                } else if (priority == P_NORMAL) {
                        /* 
                         *  Must delay disconnect til after all data segments
                         *  have been sent an the tx_queue is empty
                         */
                        if (userdata)
                                self->disconnect_skb = userdata;
                        else
                                self->disconnect_skb = NULL;

                        self->disconnect_pend = TRUE;

                        irttp_run_tx_queue(self);

                        irttp_start_todo_timer(self, MSECS_TO_JIFFIES(1000));
                        return -1;
                }
        }
        IRDA_DEBUG(1, __FUNCTION__ "(), Disconnecting ...\n");

        self->connected = FALSE;
        
        if (!userdata) {
                skb = dev_alloc_skb(64);
                if (!skb)
                        return -ENOMEM;
                
                /* 
                 *  Reserve space for MUX and LAP header 
                 */
                skb_reserve(skb, TTP_MAX_HEADER);
                
                userdata = skb;
        }
        ret = irlmp_disconnect_request(self->lsap, userdata);

        return ret;
}

/*
 * Function irttp_disconnect_indication (self, reason)
 *
 *    Disconnect indication, TSAP disconnected by peer?
 *
 */
void irttp_disconnect_indication(void *instance, void *sap, LM_REASON reason, 
                                 struct sk_buff *skb) 
{
        struct tsap_cb *self;

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

        self = (struct tsap_cb *) instance;
        
        ASSERT(self != NULL, return;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
        
        self->connected = FALSE;
        
        /* Check if client has already tried to close the TSAP */
        if (self->close_pend) {
                irttp_close_tsap(self);
                return;
        }

        /* No need to notify the client if has already tried to disconnect */
        if (self->disconnect_pend)
                return;
        
        if (self->notify.disconnect_indication)
                self->notify.disconnect_indication(self->notify.instance, self,
                                                   reason, skb);
        else
                if (skb)
                        dev_kfree_skb(skb);
}

/*
 * Function irttp_do_data_indication (self, skb)
 *
 *    Try to deliver reassebled skb to layer above, and requeue it if that
 *    for some reason should fail. We mark rx sdu as busy to apply back
 *    pressure is necessary.
 */
void irttp_do_data_indication(struct tsap_cb *self, struct sk_buff *skb)
{
        int err;

        /* Check if client has already tried to close the TSAP */
        if (self->close_pend || self->disconnect_pend) {
                dev_kfree_skb(skb);
                return;
        }

        err = self->notify.data_indication(self->notify.instance, self, skb);

        /* Usually the layer above will notify that it's input queue is
         * starting to get filled by using the flow request, but this may
         * be difficult, so it can instead just refuse to eat it and just
         * give an error back 
         */
        if (err == -ENOMEM) {
                IRDA_DEBUG(0, __FUNCTION__ "() requeueing skb!\n");

                /* Make sure we take a break */
                self->rx_sdu_busy = TRUE;
                
                /* Need to push the header in again */
                skb_push(skb, TTP_HEADER);
                skb->data[0] = 0x00; /* Make sure MORE bit is cleared */
                
                /* Put skb back on queue */
                skb_queue_head(&self->rx_queue, skb);
        }
}

/*
 * Function irttp_run_rx_queue (self)
 *
 *     Check if we have any frames to be transmitted, or if we have any
 *     available credit to give away.
 */
void irttp_run_rx_queue(struct tsap_cb *self) 
{
        struct sk_buff *skb;
        int more = 0;

        IRDA_DEBUG(2, __FUNCTION__ "() send=%d,avail=%d,remote=%d\n", 
                   self->send_credit, self->avail_credit, self->remote_credit);

        if (irda_lock(&self->rx_queue_lock) == FALSE)
                return;
        
        /*
         *  Reassemble all frames in receive queue and deliver them
         */
        while (!self->rx_sdu_busy && (skb = skb_dequeue(&self->rx_queue))) {
                self->avail_credit++;

                more = skb->data[0] & 0x80;

                /* Remove TTP header */
                skb_pull(skb, TTP_HEADER);

                /* Add the length of the remaining data */
                self->rx_sdu_size += skb->len;

                /*  
                 * If SAR is disabled, or user has requested no reassembly
                 * of received fragements then we just deliver them
                 * immediately. This can be requested by clients that
                 * implements byte streams without any message boundaries
                 */
                if (self->rx_max_sdu_size == TTP_SAR_DISABLE) {
                        irttp_do_data_indication(self, skb);
                        self->rx_sdu_size = 0;

                        continue;
                }

                /* Check if this is a fragment, and not the last fragment */
                if (more) {
                        /*  
                         *  Queue the fragment if we still are within the 
                         *  limits of the maximum size of the rx_sdu
                         */
                        if (self->rx_sdu_size <= self->rx_max_sdu_size) {
                                IRDA_DEBUG(4, __FUNCTION__ "(), queueing frag\n");
                                skb_queue_tail(&self->rx_fragments, skb);
                        } else {
                                /* Free the part of the SDU that is too big */
                                dev_kfree_skb(skb);
                        }
                        continue;
                }
                /*
                 *  This is the last fragment, so time to reassemble!
                 */
                if ((self->rx_sdu_size <= self->rx_max_sdu_size) ||
                    (self->rx_max_sdu_size == TTP_SAR_UNBOUND)) 
                {
                        /* 
                         * A little optimizing. Only queue the fragment if
                         * there are other fragments. Since if this is the
                         * last and only fragment, there is no need to
                         * reassemble :-) 
                         */
                        if (!skb_queue_empty(&self->rx_fragments)) {
                                skb_queue_tail(&self->rx_fragments, 
                                               skb);
                                
                                skb = irttp_reassemble_skb(self);
                        }
                        
                        /* Now we can deliver the reassembled skb */
                        irttp_do_data_indication(self, skb);
                } else {
                        IRDA_DEBUG(1, __FUNCTION__ "(), Truncated frame\n");
                        
                        /* Free the part of the SDU that is too big */
                        dev_kfree_skb(skb);

                        /* Deliver only the valid but truncated part of SDU */
                        skb = irttp_reassemble_skb(self);
                        
                        irttp_do_data_indication(self, skb);
                }
                self->rx_sdu_size = 0;
        }
        /* Reset lock */
        self->rx_queue_lock = 0;
}

/*
 * Function irttp_flush_queues (self)
 *
 *     Flushes (removes all frames) in transitt-buffer (tx_list)
 */
void irttp_flush_queues(struct tsap_cb *self)
{
        struct sk_buff* skb;
        
        IRDA_DEBUG(4, __FUNCTION__ "()\n");

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
        
        /* Deallocate frames waiting to be sent */
        while ((skb = skb_dequeue(&self->tx_queue)) != NULL)
                dev_kfree_skb(skb);
        
        /* Deallocate received frames */
        while ((skb = skb_dequeue(&self->rx_queue)) != NULL)
                dev_kfree_skb(skb);
        
        /* Deallocate received fragments */
        while ((skb = skb_dequeue(&self->rx_fragments)) != NULL)
                dev_kfree_skb(skb);
}

/*
 * Function irttp_reasseble (self)
 *
 *    Makes a new (continuous) skb of all the fragments in the fragment
 *    queue
 *
 */
static struct sk_buff *irttp_reassemble_skb(struct tsap_cb *self)
{
        struct sk_buff *skb, *frag;
        int n = 0;  /* Fragment index */
        
        ASSERT(self != NULL, return NULL;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return NULL;);

        IRDA_DEBUG(2, __FUNCTION__ "(), self->rx_sdu_size=%d\n", 
                   self->rx_sdu_size);

        skb = dev_alloc_skb(TTP_HEADER + self->rx_sdu_size);
        if (!skb)
                return NULL;

        /* 
         * Need to reserve space for TTP header in case this skb needs to 
         * be requeued in case delivery failes
         */
        skb_reserve(skb, TTP_HEADER);
        skb_put(skb, self->rx_sdu_size);

        /*
         *  Copy all fragments to a new buffer
         */
        while ((frag = skb_dequeue(&self->rx_fragments)) != NULL) {
                memcpy(skb->data+n, frag->data, frag->len);
                n += frag->len;
                
                dev_kfree_skb(frag);
        }
        IRDA_DEBUG(2, __FUNCTION__ "(), frame len=%d\n", n);

        IRDA_DEBUG(2, __FUNCTION__ "(), rx_sdu_size=%d\n", self->rx_sdu_size);
        ASSERT(n <= self->rx_sdu_size, return NULL;);

        /* Set the new length */
        skb_trim(skb, n);

        self->rx_sdu_size = 0;

        return skb;
}

/*
 * Function irttp_fragment_skb (skb)
 *
 *    Fragments a frame and queues all the fragments for transmission
 *
 */
static void irttp_fragment_skb(struct tsap_cb *self, struct sk_buff *skb)
{
        struct sk_buff *frag;
        __u8 *frame;

        IRDA_DEBUG(2, __FUNCTION__ "()\n");

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
        ASSERT(skb != NULL, return;);

        /*
         *  Split frame into a number of segments
         */
        while (skb->len > self->max_seg_size) {
                IRDA_DEBUG(2, __FUNCTION__  "(), fragmenting ...\n");

                /* Make new segment */
                frag = dev_alloc_skb(self->max_seg_size+self->max_header_size);
                if (!frag)
                        return;

                skb_reserve(frag, self->max_header_size);

                /* Copy data from the original skb into this fragment. */
                memcpy(skb_put(frag, self->max_seg_size), skb->data, 
                       self->max_seg_size);

                /* Insert TTP header, with the more bit set */
                frame = skb_push(frag, TTP_HEADER);
                frame[0] = TTP_MORE;
                
                /* Hide the copied data from the original skb */
                skb_pull(skb, self->max_seg_size);

                /* Queue fragment */
                skb_queue_tail(&self->tx_queue, frag);
        }
        /* Queue what is left of the original skb */
        IRDA_DEBUG(2, __FUNCTION__  "(), queuing last segment\n");
        
        frame = skb_push(skb, TTP_HEADER);
        frame[0] = 0x00; /* Clear more bit */

        /* Queue fragment */
        skb_queue_tail(&self->tx_queue, skb);
}

/*
 * Function irttp_param_max_sdu_size (self, param)
 *
 *    Handle the MaxSduSize parameter in the connect frames, this function
 *    will be called both when this parameter needs to be inserted into, and
 *    extracted from the connect frames
 */
static int irttp_param_max_sdu_size(void *instance, irda_param_t *param, 
                                    int get)
{
        struct tsap_cb *self;

        self = (struct tsap_cb *) instance;

        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);

        if (get)
                param->pv.i = self->tx_max_sdu_size;
        else
                self->tx_max_sdu_size = param->pv.i;

        IRDA_DEBUG(0, __FUNCTION__ "(), MaxSduSize=%d\n", param->pv.i);
        
        return 0;
}

/*
 * Function irttp_todo_expired (data)
 *
 *    Todo timer has expired!
 *
 */
static void irttp_todo_expired(unsigned long data)
{
        struct tsap_cb *self = (struct tsap_cb *) data;

        /* Check that we still exist */
        if (!self || self->magic != TTP_TSAP_MAGIC)
                return;
        
        irttp_run_rx_queue(self);
        irttp_run_tx_queue(self);
                
        /*  Give avay some credits to peer?  */
        if ((self->remote_credit < TTP_LOW_THRESHOLD) && 
            (self->avail_credit > 0) && (skb_queue_empty(&self->tx_queue)))
        {
                irttp_give_credit(self);
        }

        /* Check if time for disconnect */
        if (self->disconnect_pend) {
                /* Check if it's possible to disconnect yet */
                if (skb_queue_empty(&self->tx_queue)) {
                        
                        /* Make sure disconnect is not pending anymore */
                        self->disconnect_pend = FALSE;
                        if (self->disconnect_skb) {
                                irttp_disconnect_request(
                                        self, self->disconnect_skb, P_NORMAL);
                                self->disconnect_skb = NULL;
                        } else
                                irttp_disconnect_request(self, NULL,