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irttp.c
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/*********************************************************************
*
* Filename: irttp.c
* Version: 1.2
* Description: Tiny Transport Protocol (TTP) implementation
* Status: Stable
* Author: Dag Brattli <[email protected]>
* Created at: Sun Aug 31 20:14:31 1997
* Modified at: Wed Jan 5 11:31:27 2000
* Modified by: Dag Brattli <[email protected]>
*
* Copyright (c) 1998-2000 Dag Brattli <[email protected]>,
* All Rights Reserved.
* Copyright (c) 2000-2003 Jean Tourrilhes <[email protected]>
*
* 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/skbuff.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include <net/irda/irda.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;
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 struct sk_buff *irttp_reassemble_skb(struct tsap_cb *self);
static void irttp_todo_expired(unsigned long data);
static int irttp_param_max_sdu_size(void *instance, irda_param_t *param,
int get);
static void irttp_flow_indication(void *instance, void *sap, LOCAL_FLOW flow);
static void irttp_status_indication(void *instance,
LINK_STATUS link, LOCK_STATUS lock);
/* 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 };
/************************ GLOBAL PROCEDURES ************************/
/*
* Function irttp_init (void)
*
* Initialize the IrTTP layer. Called by module initialization code
*
*/
int __init irttp_init(void)
{
irttp = kzalloc(sizeof(struct irttp_cb), GFP_KERNEL);
if (irttp == NULL)
return -ENOMEM;
irttp->magic = TTP_MAGIC;
irttp->tsaps = hashbin_new(HB_LOCK);
if (!irttp->tsaps) {
IRDA_ERROR("%s: can't allocate IrTTP hashbin!\n",
__func__);
kfree(irttp);
return -ENOMEM;
}
return 0;
}
/*
* Function irttp_cleanup (void)
*
* Called by module destruction/cleanup code
*
*/
void irttp_cleanup(void)
{
/* Check for main structure */
IRDA_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;
}
/*************************** SUBROUTINES ***************************/
/*
* Function irttp_start_todo_timer (self, timeout)
*
* Start todo timer.
*
* Made it more effient and unsensitive to race conditions - Jean II
*/
static inline void irttp_start_todo_timer(struct tsap_cb *self, int timeout)
{
/* Set new value for timer */
mod_timer(&self->todo_timer, jiffies + timeout);
}
/*
* Function irttp_todo_expired (data)
*
* Todo timer has expired!
*
* One of the restriction of the timer is that it is run only on the timer
* interrupt which run every 10ms. This mean that even if you set the timer
* with a delay of 0, it may take up to 10ms before it's run.
* So, to minimise latency and keep cache fresh, we try to avoid using
* it as much as possible.
* Note : we can't use tasklets, because they can't be asynchronously
* killed (need user context), and we can't guarantee that here...
* Jean II
*/
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;
IRDA_DEBUG(4, "%s(instance=%p)\n", __func__, self);
/* Try to make some progress, especially on Tx side - Jean II */
irttp_run_rx_queue(self);
irttp_run_tx_queue(self);
/* Check if time for disconnect */
if (test_bit(0, &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 */
clear_bit(0, &self->disconnect_pend); /* FALSE */
/* Note : self->disconnect_skb may be NULL */
irttp_disconnect_request(self, self->disconnect_skb,
P_NORMAL);
self->disconnect_skb = NULL;
} else {
/* Try again later */
irttp_start_todo_timer(self, HZ/10);
/* No reason to try and close now */
return;
}
}
/* Check if it's closing time */
if (self->close_pend)
/* Finish cleanup */
irttp_close_tsap(self);
}
/*
* Function irttp_flush_queues (self)
*
* Flushes (removes all frames) in transitt-buffer (tx_list)
*/
static void irttp_flush_queues(struct tsap_cb *self)
{
struct sk_buff* skb;
IRDA_DEBUG(4, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return;);
IRDA_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_reassemble (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 */
IRDA_ASSERT(self != NULL, return NULL;);
IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return NULL;);
IRDA_DEBUG(2, "%s(), self->rx_sdu_size=%d\n", __func__,
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) {
skb_copy_to_linear_data_offset(skb, n, frag->data, frag->len);
n += frag->len;
dev_kfree_skb(frag);
}
IRDA_DEBUG(2,
"%s(), frame len=%d, rx_sdu_size=%d, rx_max_sdu_size=%d\n",
__func__, n, self->rx_sdu_size, self->rx_max_sdu_size);
/* Note : irttp_run_rx_queue() calculate self->rx_sdu_size
* by summing the size of all fragments, so we should always
* have n == self->rx_sdu_size, except in cases where we
* droped the last fragment (when self->rx_sdu_size exceed
* self->rx_max_sdu_size), where n < self->rx_sdu_size.
* Jean II */
IRDA_ASSERT(n <= self->rx_sdu_size, n = self->rx_sdu_size;);
/* 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 inline void irttp_fragment_skb(struct tsap_cb *self,
struct sk_buff *skb)
{
struct sk_buff *frag;
__u8 *frame;
IRDA_DEBUG(2, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
IRDA_ASSERT(skb != NULL, return;);
/*
* Split frame into a number of segments
*/
while (skb->len > self->max_seg_size) {
IRDA_DEBUG(2, "%s(), fragmenting ...\n", __func__);
/* Make new segment */
frag = alloc_skb(self->max_seg_size+self->max_header_size,
GFP_ATOMIC);
if (!frag)
return;
skb_reserve(frag, self->max_header_size);
/* Copy data from the original skb into this fragment. */
skb_copy_from_linear_data(skb, skb_put(frag, self->max_seg_size),
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, "%s(), queuing last segment\n", __func__);
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 = instance;
IRDA_ASSERT(self != NULL, return -1;);
IRDA_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(1, "%s(), MaxSduSize=%d\n", __func__, param->pv.i);
return 0;
}
/*************************** CLIENT CALLS ***************************/
/************************** LMP CALLBACKS **************************/
/* Everything is happily mixed up. Waiting for next clean up - Jean II */
/*
* Initialization, that has to be done on new tsap
* instance allocation and on duplication
*/
static void irttp_init_tsap(struct tsap_cb *tsap)
{
spin_lock_init(&tsap->lock);
init_timer(&tsap->todo_timer);
skb_queue_head_init(&tsap->rx_queue);
skb_queue_head_init(&tsap->tx_queue);
skb_queue_head_init(&tsap->rx_fragments);
}
/*
* 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;
IRDA_ASSERT(irttp->magic == TTP_MAGIC, return NULL;);
/* The IrLMP spec (IrLMP 1.1 p10) says that we have the right to
* use only 0x01-0x6F. Of course, we can use LSAP_ANY as well.
* JeanII */
if((stsap_sel != LSAP_ANY) &&
((stsap_sel < 0x01) || (stsap_sel >= 0x70))) {
IRDA_DEBUG(0, "%s(), invalid tsap!\n", __func__);
return NULL;
}
self = kzalloc(sizeof(struct tsap_cb), GFP_ATOMIC);
if (self == NULL) {
IRDA_DEBUG(0, "%s(), unable to kmalloc!\n", __func__);
return NULL;
}
/* Initialize internal objects */
irttp_init_tsap(self);
/* Initialise todo timer */
self->todo_timer.data = (unsigned long) self;
self->todo_timer.function = &irttp_todo_expired;
/* 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.flow_indication = irttp_flow_indication;
if(notify->status_indication != NULL)
ttp_notify.status_indication = irttp_status_indication;
ttp_notify.instance = self;
strncpy(ttp_notify.name, notify->name, NOTIFY_MAX_NAME);
self->magic = TTP_TSAP_MAGIC;
self->connected = FALSE;
/*
* Create LSAP at IrLMP layer
*/
lsap = irlmp_open_lsap(stsap_sel, &ttp_notify, 0);
if (lsap == NULL) {
IRDA_WARNING("%s: unable to allocate LSAP!!\n", __func__);
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, "%s(), stsap_sel=%02x\n", __func__, self->stsap_sel);
self->notify = *notify;
self->lsap = lsap;
hashbin_insert(irttp->tsaps, (irda_queue_t *) self, (long) self, NULL);
if (credit > TTP_RX_MAX_CREDIT)
self->initial_credit = TTP_RX_MAX_CREDIT;
else
self->initial_credit = credit;
return self;
}
EXPORT_SYMBOL(irttp_open_tsap);
/*
* 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. */
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
irttp_flush_queues(self);
del_timer(&self->todo_timer);
/* This one won't be cleaned up if we are disconnect_pend + close_pend
* and we receive a disconnect_indication */
if (self->disconnect_skb)
dev_kfree_skb(self->disconnect_skb);
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
*
* Note : because we *free* the tsap structure, it is the responsibility
* of the caller to make sure we are called only once and to deal with
* possible race conditions. - Jean II
*/
int irttp_close_tsap(struct tsap_cb *self)
{
struct tsap_cb *tsap;
IRDA_DEBUG(4, "%s()\n", __func__);
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
/* Make sure tsap has been disconnected */
if (self->connected) {
/* Check if disconnect is not pending */
if (!test_bit(0, &self->disconnect_pend)) {
IRDA_WARNING("%s: TSAP still connected!\n",
__func__);
irttp_disconnect_request(self, NULL, P_NORMAL);
}
self->close_pend = TRUE;
irttp_start_todo_timer(self, HZ/10);
return 0; /* Will be back! */
}
tsap = hashbin_remove(irttp->tsaps, (long) self, NULL);
IRDA_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;
}
EXPORT_SYMBOL(irttp_close_tsap);
/*
* Function irttp_udata_request (self, skb)
*
* Send unreliable data on this TSAP
*
*/
int irttp_udata_request(struct tsap_cb *self, struct sk_buff *skb)
{
int ret;
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
IRDA_ASSERT(skb != NULL, return -1;);
IRDA_DEBUG(4, "%s()\n", __func__);
/* Take shortcut on zero byte packets */
if (skb->len == 0) {
ret = 0;
goto err;
}
/* Check that nothing bad happens */
if (!self->connected) {
IRDA_WARNING("%s(), Not connected\n", __func__);
ret = -ENOTCONN;
goto err;
}
if (skb->len > self->max_seg_size) {
IRDA_ERROR("%s(), UData is too large for IrLAP!\n", __func__);
ret = -EMSGSIZE;
goto err;
}
irlmp_udata_request(self->lsap, skb);
self->stats.tx_packets++;
return 0;
err:
dev_kfree_skb(skb);
return ret;
}
EXPORT_SYMBOL(irttp_udata_request);
/*
* 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;
int ret;
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
IRDA_ASSERT(skb != NULL, return -1;);
IRDA_DEBUG(2, "%s() : queue len = %d\n", __func__,
skb_queue_len(&self->tx_queue));
/* Take shortcut on zero byte packets */
if (skb->len == 0) {
ret = 0;
goto err;
}
/* Check that nothing bad happens */
if (!self->connected) {
IRDA_WARNING("%s: Not connected\n", __func__);
ret = -ENOTCONN;
goto err;
}
/*
* 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)) {
IRDA_ERROR("%s: SAR disabled, and data is too large for IrLAP!\n",
__func__);
ret = -EMSGSIZE;
goto err;
}
/*
* 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))
{
IRDA_ERROR("%s: SAR enabled, but data is larger than TxMaxSduSize!\n",
__func__);
ret = -EMSGSIZE;
goto err;
}
/*
* Check if transmit queue is full
*/
if (skb_queue_len(&self->tx_queue) >= TTP_TX_MAX_QUEUE) {
/*
* Give it a chance to empty itself
*/
irttp_run_tx_queue(self);
/* Drop packet. This error code should trigger the caller
* to resend the data in the client code - Jean II */
ret = -ENOBUFS;
goto err;
}
/* Queue frame, or queue frame segments */
if ((self->tx_max_sdu_size == 0) || (skb->len < self->max_seg_size)) {
/* Queue frame */
IRDA_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 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_TX_HIGH_THRESHOLD)) {
/* Tx queue filling up, so stop client. */
if (self->notify.flow_indication) {
self->notify.flow_indication(self->notify.instance,
self, FLOW_STOP);
}
/* self->tx_sdu_busy is the state of the client.
* Update state after notifying client to avoid
* race condition with irttp_flow_indication().
* If the queue empty itself after our test but before
* we set the flag, we will fix ourselves below in
* irttp_run_tx_queue().
* Jean II */
self->tx_sdu_busy = TRUE;
}
/* Try to make some progress */
irttp_run_tx_queue(self);
return 0;
err:
dev_kfree_skb(skb);
return ret;
}
EXPORT_SYMBOL(irttp_data_request);
/*
* 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;
IRDA_DEBUG(2, "%s() : send_credit = %d, queue_len = %d\n",
__func__,
self->send_credit, skb_queue_len(&self->tx_queue));
/* Get exclusive access to the tx queue, otherwise don't touch it */
if (irda_lock(&self->tx_queue_lock) == FALSE)
return;
/* Try to send out frames as long as we have credits
* and as long as LAP is not full. If LAP is full, it will
* poll us through irttp_flow_indication() - Jean II */
while ((self->send_credit > 0) &&
(!irlmp_lap_tx_queue_full(self->lsap)) &&
(skb = skb_dequeue(&self->tx_queue)))
{
/*
* 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);
/* Detach from socket.
* The current skb has a reference to the socket that sent
* it (skb->sk). When we pass it to IrLMP, the skb will be
* stored in in IrLAP (self->wx_list). When we are within
* IrLAP, we lose the notion of socket, so we should not
* have a reference to a socket. So, we drop it here.
*
* Why does it matter ?
* When the skb is freed (kfree_skb), if it is associated
* with a socket, it release buffer space on the socket
* (through sock_wfree() and sock_def_write_space()).
* If the socket no longer exist, we may crash. Hard.
* When we close a socket, we make sure that associated packets
* in IrTTP are freed. However, we have no way to cancel
* the packet that we have passed to IrLAP. So, if a packet
* remains in IrLAP (retry on the link or else) after we
* close the socket, we are dead !
* Jean II */
if (skb->sk != NULL) {
/* IrSOCK application, IrOBEX, ... */
skb_orphan(skb);
}
/* IrCOMM over IrTTP, IrLAN, ... */
/* Pass the skb to IrLMP - done */
irlmp_data_request(self->lsap, skb);
self->stats.tx_packets++;
}
/* Check if we can accept more frames from client.
* We don't want to wait until the todo timer to do that, and we
* can't use tasklets (grr...), so we are obliged to give control
* to client. That's ok, this test will be true not too often
* (max once per LAP window) and we are called from places
* where we can spend a bit of time doing stuff. - Jean II */
if ((self->tx_sdu_busy) &&
(skb_queue_len(&self->tx_queue) < TTP_TX_LOW_THRESHOLD) &&
(!self->close_pend))
{
if (self->notify.flow_indication)
self->notify.flow_indication(self->notify.instance,
self, FLOW_START);
/* self->tx_sdu_busy is the state of the client.
* We don't really have a race here, but it's always safer
* to update our state after the client - Jean II */
self->tx_sdu_busy = FALSE;
}
/* Reset lock */
self->tx_queue_lock = 0;
}
/*
* Function irttp_give_credit (self)
*
* Send a dataless flowdata TTP-PDU and give available credit to peer
* TSAP
*/
static inline void irttp_give_credit(struct tsap_cb *self)
{
struct sk_buff *tx_skb = NULL;
unsigned long flags;
int n;
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
IRDA_DEBUG(4, "%s() send=%d,avail=%d,remote=%d\n",
__func__,
self->send_credit, self->avail_credit, self->remote_credit);
/* Give credit to peer */
tx_skb = alloc_skb(TTP_MAX_HEADER, GFP_ATOMIC);
if (!tx_skb)
return;
/* Reserve space for LMP, and LAP header */
skb_reserve(tx_skb, LMP_MAX_HEADER);
/*
* 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;
int err;
IRDA_DEBUG(4, "%s()\n", __func__);
self = instance;
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
IRDA_ASSERT(skb != NULL, return -1;);
self->stats.rx_packets++;
/* Just pass data to layer above */
if (self->notify.udata_indication) {
err = self->notify.udata_indication(self->notify.instance,
self,skb);
/* Same comment as in irttp_do_data_indication() */
if (!err)
return 0;
}
/* Either no handler, or handler returns an error */
dev_kfree_skb(skb);
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;
unsigned long flags;
int n;
self = instance;
n = skb->data[0] & 0x7f; /* Extract the credits */
self->stats.rx_packets++;
/* Deal with inbound credit
* 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);
self->send_credit += n;
if (skb->len > 1)
self->remote_credit--;
spin_unlock_irqrestore(&self->lock, flags);
/*
* Data or dataless packet? Dataless frames contains only the
* TTP_HEADER.
*/
if (skb->len > 1) {
/*
* 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 {
/* Dataless flowdata TTP-PDU */
dev_kfree_skb(skb);
}
/* Push data to the higher layer.
* We do it synchronously because running the todo timer for each
* receive packet would be too much overhead and latency.
* By passing control to the higher layer, we run the risk that
* it may take time or grab a lock. Most often, the higher layer
* will only put packet in a queue.
* Anyway, packets are only dripping through the IrDA, so we can
* have time before the next packet.
* Further, we are run from NET_BH, so the worse that can happen is
* us missing the optimal time to send back the PF bit in LAP.
* Jean II */
irttp_run_rx_queue(self);
/* We now give credits to peer in irttp_run_rx_queue().
* We need to send credit *NOW*, otherwise we are going
* to miss the next Tx window. The todo timer may take
* a while before it's run... - Jean II */
/*
* If the peer device has given us some credits and we didn't have
* anyone from before, then we need to shedule the tx queue.
* We need to do that because our Tx have stopped (so we may not
* get any LAP flow indication) and the user may be stopped as
* well. - Jean II
*/
if (self->send_credit == n) {
/* Restart pushing stuff to LAP */
irttp_run_tx_queue(self);
/* Note : we don't want to schedule the todo timer
* because it has horrible latency. No tasklets
* because the tasklet API is broken. - Jean II */
}
return 0;
}
/*
* Function irttp_status_indication (self, reason)
*
* Status_indication, just pass to the higher layer...
*
*/
static void irttp_status_indication(void *instance,
LINK_STATUS link, LOCK_STATUS lock)
{
struct tsap_cb *self;
IRDA_DEBUG(4, "%s()\n", __func__);
self = instance;