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Linux/net/irda/irttp.c

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  1 /*********************************************************************
  2  *
  3  * Filename:      irttp.c
  4  * Version:       1.2
  5  * Description:   Tiny Transport Protocol (TTP) implementation
  6  * Status:        Stable
  7  * Author:        Dag Brattli <dagb@cs.uit.no>
  8  * Created at:    Sun Aug 31 20:14:31 1997
  9  * Modified at:   Wed Jan  5 11:31:27 2000
 10  * Modified by:   Dag Brattli <dagb@cs.uit.no>
 11  *
 12  *     Copyright (c) 1998-2000 Dag Brattli <dagb@cs.uit.no>,
 13  *     All Rights Reserved.
 14  *     Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
 15  *
 16  *     This program is free software; you can redistribute it and/or
 17  *     modify it under the terms of the GNU General Public License as
 18  *     published by the Free Software Foundation; either version 2 of
 19  *     the License, or (at your option) any later version.
 20  *
 21  *     Neither Dag Brattli nor University of Tromsø admit liability nor
 22  *     provide warranty for any of this software. This material is
 23  *     provided "AS-IS" and at no charge.
 24  *
 25  ********************************************************************/
 26 
 27 #include <linux/skbuff.h>
 28 #include <linux/init.h>
 29 #include <linux/fs.h>
 30 #include <linux/seq_file.h>
 31 #include <linux/slab.h>
 32 #include <linux/export.h>
 33 
 34 #include <asm/byteorder.h>
 35 #include <asm/unaligned.h>
 36 
 37 #include <net/irda/irda.h>
 38 #include <net/irda/irlap.h>
 39 #include <net/irda/irlmp.h>
 40 #include <net/irda/parameters.h>
 41 #include <net/irda/irttp.h>
 42 
 43 static struct irttp_cb *irttp;
 44 
 45 static void __irttp_close_tsap(struct tsap_cb *self);
 46 
 47 static int irttp_data_indication(void *instance, void *sap,
 48                                  struct sk_buff *skb);
 49 static int irttp_udata_indication(void *instance, void *sap,
 50                                   struct sk_buff *skb);
 51 static void irttp_disconnect_indication(void *instance, void *sap,
 52                                         LM_REASON reason, struct sk_buff *);
 53 static void irttp_connect_indication(void *instance, void *sap,
 54                                      struct qos_info *qos, __u32 max_sdu_size,
 55                                      __u8 header_size, struct sk_buff *skb);
 56 static void irttp_connect_confirm(void *instance, void *sap,
 57                                   struct qos_info *qos, __u32 max_sdu_size,
 58                                   __u8 header_size, struct sk_buff *skb);
 59 static void irttp_run_tx_queue(struct tsap_cb *self);
 60 static void irttp_run_rx_queue(struct tsap_cb *self);
 61 
 62 static void irttp_flush_queues(struct tsap_cb *self);
 63 static void irttp_fragment_skb(struct tsap_cb *self, struct sk_buff *skb);
 64 static struct sk_buff *irttp_reassemble_skb(struct tsap_cb *self);
 65 static void irttp_todo_expired(unsigned long data);
 66 static int irttp_param_max_sdu_size(void *instance, irda_param_t *param,
 67                                     int get);
 68 
 69 static void irttp_flow_indication(void *instance, void *sap, LOCAL_FLOW flow);
 70 static void irttp_status_indication(void *instance,
 71                                     LINK_STATUS link, LOCK_STATUS lock);
 72 
 73 /* Information for parsing parameters in IrTTP */
 74 static pi_minor_info_t pi_minor_call_table[] = {
 75         { NULL, 0 },                                             /* 0x00 */
 76         { irttp_param_max_sdu_size, PV_INTEGER | PV_BIG_ENDIAN } /* 0x01 */
 77 };
 78 static pi_major_info_t pi_major_call_table[] = {{ pi_minor_call_table, 2 }};
 79 static pi_param_info_t param_info = { pi_major_call_table, 1, 0x0f, 4 };
 80 
 81 /************************ GLOBAL PROCEDURES ************************/
 82 
 83 /*
 84  * Function irttp_init (void)
 85  *
 86  *    Initialize the IrTTP layer. Called by module initialization code
 87  *
 88  */
 89 int __init irttp_init(void)
 90 {
 91         irttp = kzalloc(sizeof(struct irttp_cb), GFP_KERNEL);
 92         if (irttp == NULL)
 93                 return -ENOMEM;
 94 
 95         irttp->magic = TTP_MAGIC;
 96 
 97         irttp->tsaps = hashbin_new(HB_LOCK);
 98         if (!irttp->tsaps) {
 99                 IRDA_ERROR("%s: can't allocate IrTTP hashbin!\n",
100                            __func__);
101                 kfree(irttp);
102                 return -ENOMEM;
103         }
104 
105         return 0;
106 }
107 
108 /*
109  * Function irttp_cleanup (void)
110  *
111  *    Called by module destruction/cleanup code
112  *
113  */
114 void irttp_cleanup(void)
115 {
116         /* Check for main structure */
117         IRDA_ASSERT(irttp->magic == TTP_MAGIC, return;);
118 
119         /*
120          *  Delete hashbin and close all TSAP instances in it
121          */
122         hashbin_delete(irttp->tsaps, (FREE_FUNC) __irttp_close_tsap);
123 
124         irttp->magic = 0;
125 
126         /* De-allocate main structure */
127         kfree(irttp);
128 
129         irttp = NULL;
130 }
131 
132 /*************************** SUBROUTINES ***************************/
133 
134 /*
135  * Function irttp_start_todo_timer (self, timeout)
136  *
137  *    Start todo timer.
138  *
139  * Made it more effient and unsensitive to race conditions - Jean II
140  */
141 static inline void irttp_start_todo_timer(struct tsap_cb *self, int timeout)
142 {
143         /* Set new value for timer */
144         mod_timer(&self->todo_timer, jiffies + timeout);
145 }
146 
147 /*
148  * Function irttp_todo_expired (data)
149  *
150  *    Todo timer has expired!
151  *
152  * One of the restriction of the timer is that it is run only on the timer
153  * interrupt which run every 10ms. This mean that even if you set the timer
154  * with a delay of 0, it may take up to 10ms before it's run.
155  * So, to minimise latency and keep cache fresh, we try to avoid using
156  * it as much as possible.
157  * Note : we can't use tasklets, because they can't be asynchronously
158  * killed (need user context), and we can't guarantee that here...
159  * Jean II
160  */
161 static void irttp_todo_expired(unsigned long data)
162 {
163         struct tsap_cb *self = (struct tsap_cb *) data;
164 
165         /* Check that we still exist */
166         if (!self || self->magic != TTP_TSAP_MAGIC)
167                 return;
168 
169         IRDA_DEBUG(4, "%s(instance=%p)\n", __func__, self);
170 
171         /* Try to make some progress, especially on Tx side - Jean II */
172         irttp_run_rx_queue(self);
173         irttp_run_tx_queue(self);
174 
175         /* Check if time for disconnect */
176         if (test_bit(0, &self->disconnect_pend)) {
177                 /* Check if it's possible to disconnect yet */
178                 if (skb_queue_empty(&self->tx_queue)) {
179                         /* Make sure disconnect is not pending anymore */
180                         clear_bit(0, &self->disconnect_pend);   /* FALSE */
181 
182                         /* Note : self->disconnect_skb may be NULL */
183                         irttp_disconnect_request(self, self->disconnect_skb,
184                                                  P_NORMAL);
185                         self->disconnect_skb = NULL;
186                 } else {
187                         /* Try again later */
188                         irttp_start_todo_timer(self, HZ/10);
189 
190                         /* No reason to try and close now */
191                         return;
192                 }
193         }
194 
195         /* Check if it's closing time */
196         if (self->close_pend)
197                 /* Finish cleanup */
198                 irttp_close_tsap(self);
199 }
200 
201 /*
202  * Function irttp_flush_queues (self)
203  *
204  *     Flushes (removes all frames) in transitt-buffer (tx_list)
205  */
206 static void irttp_flush_queues(struct tsap_cb *self)
207 {
208         struct sk_buff* skb;
209 
210         IRDA_DEBUG(4, "%s()\n", __func__);
211 
212         IRDA_ASSERT(self != NULL, return;);
213         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
214 
215         /* Deallocate frames waiting to be sent */
216         while ((skb = skb_dequeue(&self->tx_queue)) != NULL)
217                 dev_kfree_skb(skb);
218 
219         /* Deallocate received frames */
220         while ((skb = skb_dequeue(&self->rx_queue)) != NULL)
221                 dev_kfree_skb(skb);
222 
223         /* Deallocate received fragments */
224         while ((skb = skb_dequeue(&self->rx_fragments)) != NULL)
225                 dev_kfree_skb(skb);
226 }
227 
228 /*
229  * Function irttp_reassemble (self)
230  *
231  *    Makes a new (continuous) skb of all the fragments in the fragment
232  *    queue
233  *
234  */
235 static struct sk_buff *irttp_reassemble_skb(struct tsap_cb *self)
236 {
237         struct sk_buff *skb, *frag;
238         int n = 0;  /* Fragment index */
239 
240         IRDA_ASSERT(self != NULL, return NULL;);
241         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return NULL;);
242 
243         IRDA_DEBUG(2, "%s(), self->rx_sdu_size=%d\n", __func__,
244                    self->rx_sdu_size);
245 
246         skb = dev_alloc_skb(TTP_HEADER + self->rx_sdu_size);
247         if (!skb)
248                 return NULL;
249 
250         /*
251          * Need to reserve space for TTP header in case this skb needs to
252          * be requeued in case delivery failes
253          */
254         skb_reserve(skb, TTP_HEADER);
255         skb_put(skb, self->rx_sdu_size);
256 
257         /*
258          *  Copy all fragments to a new buffer
259          */
260         while ((frag = skb_dequeue(&self->rx_fragments)) != NULL) {
261                 skb_copy_to_linear_data_offset(skb, n, frag->data, frag->len);
262                 n += frag->len;
263 
264                 dev_kfree_skb(frag);
265         }
266 
267         IRDA_DEBUG(2,
268                    "%s(), frame len=%d, rx_sdu_size=%d, rx_max_sdu_size=%d\n",
269                    __func__, n, self->rx_sdu_size, self->rx_max_sdu_size);
270         /* Note : irttp_run_rx_queue() calculate self->rx_sdu_size
271          * by summing the size of all fragments, so we should always
272          * have n == self->rx_sdu_size, except in cases where we
273          * droped the last fragment (when self->rx_sdu_size exceed
274          * self->rx_max_sdu_size), where n < self->rx_sdu_size.
275          * Jean II */
276         IRDA_ASSERT(n <= self->rx_sdu_size, n = self->rx_sdu_size;);
277 
278         /* Set the new length */
279         skb_trim(skb, n);
280 
281         self->rx_sdu_size = 0;
282 
283         return skb;
284 }
285 
286 /*
287  * Function irttp_fragment_skb (skb)
288  *
289  *    Fragments a frame and queues all the fragments for transmission
290  *
291  */
292 static inline void irttp_fragment_skb(struct tsap_cb *self,
293                                       struct sk_buff *skb)
294 {
295         struct sk_buff *frag;
296         __u8 *frame;
297 
298         IRDA_DEBUG(2, "%s()\n", __func__);
299 
300         IRDA_ASSERT(self != NULL, return;);
301         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
302         IRDA_ASSERT(skb != NULL, return;);
303 
304         /*
305          *  Split frame into a number of segments
306          */
307         while (skb->len > self->max_seg_size) {
308                 IRDA_DEBUG(2, "%s(), fragmenting ...\n", __func__);
309 
310                 /* Make new segment */
311                 frag = alloc_skb(self->max_seg_size+self->max_header_size,
312                                  GFP_ATOMIC);
313                 if (!frag)
314                         return;
315 
316                 skb_reserve(frag, self->max_header_size);
317 
318                 /* Copy data from the original skb into this fragment. */
319                 skb_copy_from_linear_data(skb, skb_put(frag, self->max_seg_size),
320                               self->max_seg_size);
321 
322                 /* Insert TTP header, with the more bit set */
323                 frame = skb_push(frag, TTP_HEADER);
324                 frame[0] = TTP_MORE;
325 
326                 /* Hide the copied data from the original skb */
327                 skb_pull(skb, self->max_seg_size);
328 
329                 /* Queue fragment */
330                 skb_queue_tail(&self->tx_queue, frag);
331         }
332         /* Queue what is left of the original skb */
333         IRDA_DEBUG(2, "%s(), queuing last segment\n", __func__);
334 
335         frame = skb_push(skb, TTP_HEADER);
336         frame[0] = 0x00; /* Clear more bit */
337 
338         /* Queue fragment */
339         skb_queue_tail(&self->tx_queue, skb);
340 }
341 
342 /*
343  * Function irttp_param_max_sdu_size (self, param)
344  *
345  *    Handle the MaxSduSize parameter in the connect frames, this function
346  *    will be called both when this parameter needs to be inserted into, and
347  *    extracted from the connect frames
348  */
349 static int irttp_param_max_sdu_size(void *instance, irda_param_t *param,
350                                     int get)
351 {
352         struct tsap_cb *self;
353 
354         self = instance;
355 
356         IRDA_ASSERT(self != NULL, return -1;);
357         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
358 
359         if (get)
360                 param->pv.i = self->tx_max_sdu_size;
361         else
362                 self->tx_max_sdu_size = param->pv.i;
363 
364         IRDA_DEBUG(1, "%s(), MaxSduSize=%d\n", __func__, param->pv.i);
365 
366         return 0;
367 }
368 
369 /*************************** CLIENT CALLS ***************************/
370 /************************** LMP CALLBACKS **************************/
371 /* Everything is happily mixed up. Waiting for next clean up - Jean II */
372 
373 /*
374  * Initialization, that has to be done on new tsap
375  * instance allocation and on duplication
376  */
377 static void irttp_init_tsap(struct tsap_cb *tsap)
378 {
379         spin_lock_init(&tsap->lock);
380         init_timer(&tsap->todo_timer);
381 
382         skb_queue_head_init(&tsap->rx_queue);
383         skb_queue_head_init(&tsap->tx_queue);
384         skb_queue_head_init(&tsap->rx_fragments);
385 }
386 
387 /*
388  * Function irttp_open_tsap (stsap, notify)
389  *
390  *    Create TSAP connection endpoint,
391  */
392 struct tsap_cb *irttp_open_tsap(__u8 stsap_sel, int credit, notify_t *notify)
393 {
394         struct tsap_cb *self;
395         struct lsap_cb *lsap;
396         notify_t ttp_notify;
397 
398         IRDA_ASSERT(irttp->magic == TTP_MAGIC, return NULL;);
399 
400         /* The IrLMP spec (IrLMP 1.1 p10) says that we have the right to
401          * use only 0x01-0x6F. Of course, we can use LSAP_ANY as well.
402          * JeanII */
403         if((stsap_sel != LSAP_ANY) &&
404            ((stsap_sel < 0x01) || (stsap_sel >= 0x70))) {
405                 IRDA_DEBUG(0, "%s(), invalid tsap!\n", __func__);
406                 return NULL;
407         }
408 
409         self = kzalloc(sizeof(struct tsap_cb), GFP_ATOMIC);
410         if (self == NULL) {
411                 IRDA_DEBUG(0, "%s(), unable to kmalloc!\n", __func__);
412                 return NULL;
413         }
414 
415         /* Initialize internal objects */
416         irttp_init_tsap(self);
417 
418         /* Initialise todo timer */
419         self->todo_timer.data     = (unsigned long) self;
420         self->todo_timer.function = &irttp_todo_expired;
421 
422         /* Initialize callbacks for IrLMP to use */
423         irda_notify_init(&ttp_notify);
424         ttp_notify.connect_confirm = irttp_connect_confirm;
425         ttp_notify.connect_indication = irttp_connect_indication;
426         ttp_notify.disconnect_indication = irttp_disconnect_indication;
427         ttp_notify.data_indication = irttp_data_indication;
428         ttp_notify.udata_indication = irttp_udata_indication;
429         ttp_notify.flow_indication = irttp_flow_indication;
430         if(notify->status_indication != NULL)
431                 ttp_notify.status_indication = irttp_status_indication;
432         ttp_notify.instance = self;
433         strncpy(ttp_notify.name, notify->name, NOTIFY_MAX_NAME);
434 
435         self->magic = TTP_TSAP_MAGIC;
436         self->connected = FALSE;
437 
438         /*
439          *  Create LSAP at IrLMP layer
440          */
441         lsap = irlmp_open_lsap(stsap_sel, &ttp_notify, 0);
442         if (lsap == NULL) {
443                 IRDA_DEBUG(0, "%s: unable to allocate LSAP!!\n", __func__);
444                 __irttp_close_tsap(self);
445                 return NULL;
446         }
447 
448         /*
449          *  If user specified LSAP_ANY as source TSAP selector, then IrLMP
450          *  will replace it with whatever source selector which is free, so
451          *  the stsap_sel we have might not be valid anymore
452          */
453         self->stsap_sel = lsap->slsap_sel;
454         IRDA_DEBUG(4, "%s(), stsap_sel=%02x\n", __func__, self->stsap_sel);
455 
456         self->notify = *notify;
457         self->lsap = lsap;
458 
459         hashbin_insert(irttp->tsaps, (irda_queue_t *) self, (long) self, NULL);
460 
461         if (credit > TTP_RX_MAX_CREDIT)
462                 self->initial_credit = TTP_RX_MAX_CREDIT;
463         else
464                 self->initial_credit = credit;
465 
466         return self;
467 }
468 EXPORT_SYMBOL(irttp_open_tsap);
469 
470 /*
471  * Function irttp_close (handle)
472  *
473  *    Remove an instance of a TSAP. This function should only deal with the
474  *    deallocation of the TSAP, and resetting of the TSAPs values;
475  *
476  */
477 static void __irttp_close_tsap(struct tsap_cb *self)
478 {
479         /* First make sure we're connected. */
480         IRDA_ASSERT(self != NULL, return;);
481         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
482 
483         irttp_flush_queues(self);
484 
485         del_timer(&self->todo_timer);
486 
487         /* This one won't be cleaned up if we are disconnect_pend + close_pend
488          * and we receive a disconnect_indication */
489         if (self->disconnect_skb)
490                 dev_kfree_skb(self->disconnect_skb);
491 
492         self->connected = FALSE;
493         self->magic = ~TTP_TSAP_MAGIC;
494 
495         kfree(self);
496 }
497 
498 /*
499  * Function irttp_close (self)
500  *
501  *    Remove TSAP from list of all TSAPs and then deallocate all resources
502  *    associated with this TSAP
503  *
504  * Note : because we *free* the tsap structure, it is the responsibility
505  * of the caller to make sure we are called only once and to deal with
506  * possible race conditions. - Jean II
507  */
508 int irttp_close_tsap(struct tsap_cb *self)
509 {
510         struct tsap_cb *tsap;
511 
512         IRDA_DEBUG(4, "%s()\n", __func__);
513 
514         IRDA_ASSERT(self != NULL, return -1;);
515         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
516 
517         /* Make sure tsap has been disconnected */
518         if (self->connected) {
519                 /* Check if disconnect is not pending */
520                 if (!test_bit(0, &self->disconnect_pend)) {
521                         IRDA_WARNING("%s: TSAP still connected!\n",
522                                      __func__);
523                         irttp_disconnect_request(self, NULL, P_NORMAL);
524                 }
525                 self->close_pend = TRUE;
526                 irttp_start_todo_timer(self, HZ/10);
527 
528                 return 0; /* Will be back! */
529         }
530 
531         tsap = hashbin_remove(irttp->tsaps, (long) self, NULL);
532 
533         IRDA_ASSERT(tsap == self, return -1;);
534 
535         /* Close corresponding LSAP */
536         if (self->lsap) {
537                 irlmp_close_lsap(self->lsap);
538                 self->lsap = NULL;
539         }
540 
541         __irttp_close_tsap(self);
542 
543         return 0;
544 }
545 EXPORT_SYMBOL(irttp_close_tsap);
546 
547 /*
548  * Function irttp_udata_request (self, skb)
549  *
550  *    Send unreliable data on this TSAP
551  *
552  */
553 int irttp_udata_request(struct tsap_cb *self, struct sk_buff *skb)
554 {
555         int ret;
556 
557         IRDA_ASSERT(self != NULL, return -1;);
558         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
559         IRDA_ASSERT(skb != NULL, return -1;);
560 
561         IRDA_DEBUG(4, "%s()\n", __func__);
562 
563         /* Take shortcut on zero byte packets */
564         if (skb->len == 0) {
565                 ret = 0;
566                 goto err;
567         }
568 
569         /* Check that nothing bad happens */
570         if (!self->connected) {
571                 IRDA_WARNING("%s(), Not connected\n", __func__);
572                 ret = -ENOTCONN;
573                 goto err;
574         }
575 
576         if (skb->len > self->max_seg_size) {
577                 IRDA_ERROR("%s(), UData is too large for IrLAP!\n", __func__);
578                 ret = -EMSGSIZE;
579                 goto err;
580         }
581 
582         irlmp_udata_request(self->lsap, skb);
583         self->stats.tx_packets++;
584 
585         return 0;
586 
587 err:
588         dev_kfree_skb(skb);
589         return ret;
590 }
591 EXPORT_SYMBOL(irttp_udata_request);
592 
593 
594 /*
595  * Function irttp_data_request (handle, skb)
596  *
597  *    Queue frame for transmission. If SAR is enabled, fragement the frame
598  *    and queue the fragments for transmission
599  */
600 int irttp_data_request(struct tsap_cb *self, struct sk_buff *skb)
601 {
602         __u8 *frame;
603         int ret;
604 
605         IRDA_ASSERT(self != NULL, return -1;);
606         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
607         IRDA_ASSERT(skb != NULL, return -1;);
608 
609         IRDA_DEBUG(2, "%s() : queue len = %d\n", __func__,
610                    skb_queue_len(&self->tx_queue));
611 
612         /* Take shortcut on zero byte packets */
613         if (skb->len == 0) {
614                 ret = 0;
615                 goto err;
616         }
617 
618         /* Check that nothing bad happens */
619         if (!self->connected) {
620                 IRDA_WARNING("%s: Not connected\n", __func__);
621                 ret = -ENOTCONN;
622                 goto err;
623         }
624 
625         /*
626          *  Check if SAR is disabled, and the frame is larger than what fits
627          *  inside an IrLAP frame
628          */
629         if ((self->tx_max_sdu_size == 0) && (skb->len > self->max_seg_size)) {
630                 IRDA_ERROR("%s: SAR disabled, and data is too large for IrLAP!\n",
631                            __func__);
632                 ret = -EMSGSIZE;
633                 goto err;
634         }
635 
636         /*
637          *  Check if SAR is enabled, and the frame is larger than the
638          *  TxMaxSduSize
639          */
640         if ((self->tx_max_sdu_size != 0) &&
641             (self->tx_max_sdu_size != TTP_SAR_UNBOUND) &&
642             (skb->len > self->tx_max_sdu_size))
643         {
644                 IRDA_ERROR("%s: SAR enabled, but data is larger than TxMaxSduSize!\n",
645                            __func__);
646                 ret = -EMSGSIZE;
647                 goto err;
648         }
649         /*
650          *  Check if transmit queue is full
651          */
652         if (skb_queue_len(&self->tx_queue) >= TTP_TX_MAX_QUEUE) {
653                 /*
654                  *  Give it a chance to empty itself
655                  */
656                 irttp_run_tx_queue(self);
657 
658                 /* Drop packet. This error code should trigger the caller
659                  * to resend the data in the client code - Jean II */
660                 ret = -ENOBUFS;
661                 goto err;
662         }
663 
664         /* Queue frame, or queue frame segments */
665         if ((self->tx_max_sdu_size == 0) || (skb->len < self->max_seg_size)) {
666                 /* Queue frame */
667                 IRDA_ASSERT(skb_headroom(skb) >= TTP_HEADER, return -1;);
668                 frame = skb_push(skb, TTP_HEADER);
669                 frame[0] = 0x00; /* Clear more bit */
670 
671                 skb_queue_tail(&self->tx_queue, skb);
672         } else {
673                 /*
674                  *  Fragment the frame, this function will also queue the
675                  *  fragments, we don't care about the fact the transmit
676                  *  queue may be overfilled by all the segments for a little
677                  *  while
678                  */
679                 irttp_fragment_skb(self, skb);
680         }
681 
682         /* Check if we can accept more data from client */
683         if ((!self->tx_sdu_busy) &&
684             (skb_queue_len(&self->tx_queue) > TTP_TX_HIGH_THRESHOLD)) {
685                 /* Tx queue filling up, so stop client. */
686                 if (self->notify.flow_indication) {
687                         self->notify.flow_indication(self->notify.instance,
688                                                      self, FLOW_STOP);
689                 }
690                 /* self->tx_sdu_busy is the state of the client.
691                  * Update state after notifying client to avoid
692                  * race condition with irttp_flow_indication().
693                  * If the queue empty itself after our test but before
694                  * we set the flag, we will fix ourselves below in
695                  * irttp_run_tx_queue().
696                  * Jean II */
697                 self->tx_sdu_busy = TRUE;
698         }
699 
700         /* Try to make some progress */
701         irttp_run_tx_queue(self);
702 
703         return 0;
704 
705 err:
706         dev_kfree_skb(skb);
707         return ret;
708 }
709 EXPORT_SYMBOL(irttp_data_request);
710 
711 /*
712  * Function irttp_run_tx_queue (self)
713  *
714  *    Transmit packets queued for transmission (if possible)
715  *
716  */
717 static void irttp_run_tx_queue(struct tsap_cb *self)
718 {
719         struct sk_buff *skb;
720         unsigned long flags;
721         int n;
722 
723         IRDA_DEBUG(2, "%s() : send_credit = %d, queue_len = %d\n",
724                    __func__,
725                    self->send_credit, skb_queue_len(&self->tx_queue));
726 
727         /* Get exclusive access to the tx queue, otherwise don't touch it */
728         if (irda_lock(&self->tx_queue_lock) == FALSE)
729                 return;
730 
731         /* Try to send out frames as long as we have credits
732          * and as long as LAP is not full. If LAP is full, it will
733          * poll us through irttp_flow_indication() - Jean II */
734         while ((self->send_credit > 0) &&
735                (!irlmp_lap_tx_queue_full(self->lsap)) &&
736                (skb = skb_dequeue(&self->tx_queue)))
737         {
738                 /*
739                  *  Since we can transmit and receive frames concurrently,
740                  *  the code below is a critical region and we must assure that
741                  *  nobody messes with the credits while we update them.
742                  */
743                 spin_lock_irqsave(&self->lock, flags);
744 
745                 n = self->avail_credit;
746                 self->avail_credit = 0;
747 
748                 /* Only room for 127 credits in frame */
749                 if (n > 127) {
750                         self->avail_credit = n-127;
751                         n = 127;
752                 }
753                 self->remote_credit += n;
754                 self->send_credit--;
755 
756                 spin_unlock_irqrestore(&self->lock, flags);
757 
758                 /*
759                  *  More bit must be set by the data_request() or fragment()
760                  *  functions
761                  */
762                 skb->data[0] |= (n & 0x7f);
763 
764                 /* Detach from socket.
765                  * The current skb has a reference to the socket that sent
766                  * it (skb->sk). When we pass it to IrLMP, the skb will be
767                  * stored in in IrLAP (self->wx_list). When we are within
768                  * IrLAP, we lose the notion of socket, so we should not
769                  * have a reference to a socket. So, we drop it here.
770                  *
771                  * Why does it matter ?
772                  * When the skb is freed (kfree_skb), if it is associated
773                  * with a socket, it release buffer space on the socket
774                  * (through sock_wfree() and sock_def_write_space()).
775                  * If the socket no longer exist, we may crash. Hard.
776                  * When we close a socket, we make sure that associated packets
777                  * in IrTTP are freed. However, we have no way to cancel
778                  * the packet that we have passed to IrLAP. So, if a packet
779                  * remains in IrLAP (retry on the link or else) after we
780                  * close the socket, we are dead !
781                  * Jean II */
782                 if (skb->sk != NULL) {
783                         /* IrSOCK application, IrOBEX, ... */
784                         skb_orphan(skb);
785                 }
786                         /* IrCOMM over IrTTP, IrLAN, ... */
787 
788                 /* Pass the skb to IrLMP - done */
789                 irlmp_data_request(self->lsap, skb);
790                 self->stats.tx_packets++;
791         }
792 
793         /* Check if we can accept more frames from client.
794          * We don't want to wait until the todo timer to do that, and we
795          * can't use tasklets (grr...), so we are obliged to give control
796          * to client. That's ok, this test will be true not too often
797          * (max once per LAP window) and we are called from places
798          * where we can spend a bit of time doing stuff. - Jean II */
799         if ((self->tx_sdu_busy) &&
800             (skb_queue_len(&self->tx_queue) < TTP_TX_LOW_THRESHOLD) &&
801             (!self->close_pend))
802         {
803                 if (self->notify.flow_indication)
804                         self->notify.flow_indication(self->notify.instance,
805                                                      self, FLOW_START);
806 
807                 /* self->tx_sdu_busy is the state of the client.
808                  * We don't really have a race here, but it's always safer
809                  * to update our state after the client - Jean II */
810                 self->tx_sdu_busy = FALSE;
811         }
812 
813         /* Reset lock */
814         self->tx_queue_lock = 0;
815 }
816 
817 /*
818  * Function irttp_give_credit (self)
819  *
820  *    Send a dataless flowdata TTP-PDU and give available credit to peer
821  *    TSAP
822  */
823 static inline void irttp_give_credit(struct tsap_cb *self)
824 {
825         struct sk_buff *tx_skb = NULL;
826         unsigned long flags;
827         int n;
828 
829         IRDA_ASSERT(self != NULL, return;);
830         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
831 
832         IRDA_DEBUG(4, "%s() send=%d,avail=%d,remote=%d\n",
833                    __func__,
834                    self->send_credit, self->avail_credit, self->remote_credit);
835 
836         /* Give credit to peer */
837         tx_skb = alloc_skb(TTP_MAX_HEADER, GFP_ATOMIC);
838         if (!tx_skb)
839                 return;
840 
841         /* Reserve space for LMP, and LAP header */
842         skb_reserve(tx_skb, LMP_MAX_HEADER);
843 
844         /*
845          *  Since we can transmit and receive frames concurrently,
846          *  the code below is a critical region and we must assure that
847          *  nobody messes with the credits while we update them.
848          */
849         spin_lock_irqsave(&self->lock, flags);
850 
851         n = self->avail_credit;
852         self->avail_credit = 0;
853 
854         /* Only space for 127 credits in frame */
855         if (n > 127) {
856                 self->avail_credit = n - 127;
857                 n = 127;
858         }
859         self->remote_credit += n;
860 
861         spin_unlock_irqrestore(&self->lock, flags);
862 
863         skb_put(tx_skb, 1);
864         tx_skb->data[0] = (__u8) (n & 0x7f);
865 
866         irlmp_data_request(self->lsap, tx_skb);
867         self->stats.tx_packets++;
868 }
869 
870 /*
871  * Function irttp_udata_indication (instance, sap, skb)
872  *
873  *    Received some unit-data (unreliable)
874  *
875  */
876 static int irttp_udata_indication(void *instance, void *sap,
877                                   struct sk_buff *skb)
878 {
879         struct tsap_cb *self;
880         int err;
881 
882         IRDA_DEBUG(4, "%s()\n", __func__);
883 
884         self = instance;
885 
886         IRDA_ASSERT(self != NULL, return -1;);
887         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
888         IRDA_ASSERT(skb != NULL, return -1;);
889 
890         self->stats.rx_packets++;
891 
892         /* Just pass data to layer above */
893         if (self->notify.udata_indication) {
894                 err = self->notify.udata_indication(self->notify.instance,
895                                                     self,skb);
896                 /* Same comment as in irttp_do_data_indication() */
897                 if (!err)
898                         return 0;
899         }
900         /* Either no handler, or handler returns an error */
901         dev_kfree_skb(skb);
902 
903         return 0;
904 }
905 
906 /*
907  * Function irttp_data_indication (instance, sap, skb)
908  *
909  *    Receive segment from IrLMP.
910  *
911  */
912 static int irttp_data_indication(void *instance, void *sap,
913                                  struct sk_buff *skb)
914 {
915         struct tsap_cb *self;
916         unsigned long flags;
917         int n;
918 
919         self = instance;
920 
921         n = skb->data[0] & 0x7f;     /* Extract the credits */
922 
923         self->stats.rx_packets++;
924 
925         /*  Deal with inbound credit
926          *  Since we can transmit and receive frames concurrently,
927          *  the code below is a critical region and we must assure that
928          *  nobody messes with the credits while we update them.
929          */
930         spin_lock_irqsave(&self->lock, flags);
931         self->send_credit += n;
932         if (skb->len > 1)
933                 self->remote_credit--;
934         spin_unlock_irqrestore(&self->lock, flags);
935 
936         /*
937          *  Data or dataless packet? Dataless frames contains only the
938          *  TTP_HEADER.
939          */
940         if (skb->len > 1) {
941                 /*
942                  *  We don't remove the TTP header, since we must preserve the
943                  *  more bit, so the defragment routing knows what to do
944                  */
945                 skb_queue_tail(&self->rx_queue, skb);
946         } else {
947                 /* Dataless flowdata TTP-PDU */
948                 dev_kfree_skb(skb);
949         }
950 
951 
952         /* Push data to the higher layer.
953          * We do it synchronously because running the todo timer for each
954          * receive packet would be too much overhead and latency.
955          * By passing control to the higher layer, we run the risk that
956          * it may take time or grab a lock. Most often, the higher layer
957          * will only put packet in a queue.
958          * Anyway, packets are only dripping through the IrDA, so we can
959          * have time before the next packet.
960          * Further, we are run from NET_BH, so the worse that can happen is
961          * us missing the optimal time to send back the PF bit in LAP.
962          * Jean II */
963         irttp_run_rx_queue(self);
964 
965         /* We now give credits to peer in irttp_run_rx_queue().
966          * We need to send credit *NOW*, otherwise we are going
967          * to miss the next Tx window. The todo timer may take
968          * a while before it's run... - Jean II */
969 
970         /*
971          * If the peer device has given us some credits and we didn't have
972          * anyone from before, then we need to shedule the tx queue.
973          * We need to do that because our Tx have stopped (so we may not
974          * get any LAP flow indication) and the user may be stopped as
975          * well. - Jean II
976          */
977         if (self->send_credit == n) {
978                 /* Restart pushing stuff to LAP */
979                 irttp_run_tx_queue(self);
980                 /* Note : we don't want to schedule the todo timer
981                  * because it has horrible latency. No tasklets
982                  * because the tasklet API is broken. - Jean II */
983         }
984 
985         return 0;
986 }
987 
988 /*
989  * Function irttp_status_indication (self, reason)
990  *
991  *    Status_indication, just pass to the higher layer...
992  *
993  */
994 static void irttp_status_indication(void *instance,
995                                     LINK_STATUS link, LOCK_STATUS lock)
996 {
997         struct tsap_cb *self;
998 
999         IRDA_DEBUG(4, "%s()\n", __func__);
1000 
1001         self = instance;
1002 
1003         IRDA_ASSERT(self != NULL, return;);
1004         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1005 
1006         /* Check if client has already closed the TSAP and gone away */
1007         if (self->close_pend)
1008                 return;
1009 
1010         /*
1011          *  Inform service user if he has requested it
1012          */
1013         if (self->notify.status_indication != NULL)
1014                 self->notify.status_indication(self->notify.instance,
1015                                                link, lock);
1016         else
1017                 IRDA_DEBUG(2, "%s(), no handler\n", __func__);
1018 }
1019 
1020 /*
1021  * Function irttp_flow_indication (self, reason)
1022  *
1023  *    Flow_indication : IrLAP tells us to send more data.
1024  *
1025  */
1026 static void irttp_flow_indication(void *instance, void *sap, LOCAL_FLOW flow)
1027 {
1028         struct tsap_cb *self;
1029 
1030         self = instance;
1031 
1032         IRDA_ASSERT(self != NULL, return;);
1033         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1034 
1035         IRDA_DEBUG(4, "%s(instance=%p)\n", __func__, self);
1036 
1037         /* We are "polled" directly from LAP, and the LAP want to fill
1038          * its Tx window. We want to do our best to send it data, so that
1039          * we maximise the window. On the other hand, we want to limit the
1040          * amount of work here so that LAP doesn't hang forever waiting
1041          * for packets. - Jean II */
1042 
1043         /* Try to send some packets. Currently, LAP calls us every time
1044          * there is one free slot, so we will send only one packet.
1045          * This allow the scheduler to do its round robin - Jean II */
1046         irttp_run_tx_queue(self);
1047 
1048         /* Note regarding the interraction with higher layer.
1049          * irttp_run_tx_queue() may call the client when its queue
1050          * start to empty, via notify.flow_indication(). Initially.
1051          * I wanted this to happen in a tasklet, to avoid client
1052          * grabbing the CPU, but we can't use tasklets safely. And timer
1053          * is definitely too slow.
1054          * This will happen only once per LAP window, and usually at
1055          * the third packet (unless window is smaller). LAP is still
1056          * doing mtt and sending first packet so it's sort of OK
1057          * to do that. Jean II */
1058 
1059         /* If we need to send disconnect. try to do it now */
1060         if(self->disconnect_pend)
1061                 irttp_start_todo_timer(self, 0);
1062 }
1063 
1064 /*
1065  * Function irttp_flow_request (self, command)
1066  *
1067  *    This function could be used by the upper layers to tell IrTTP to stop
1068  *    delivering frames if the receive queues are starting to get full, or
1069  *    to tell IrTTP to start delivering frames again.
1070  */
1071 void irttp_flow_request(struct tsap_cb *self, LOCAL_FLOW flow)
1072 {
1073         IRDA_DEBUG(1, "%s()\n", __func__);
1074 
1075         IRDA_ASSERT(self != NULL, return;);
1076         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1077 
1078         switch (flow) {
1079         case FLOW_STOP:
1080                 IRDA_DEBUG(1, "%s(), flow stop\n", __func__);
1081                 self->rx_sdu_busy = TRUE;
1082                 break;
1083         case FLOW_START:
1084                 IRDA_DEBUG(1, "%s(), flow start\n", __func__);
1085                 self->rx_sdu_busy = FALSE;
1086 
1087                 /* Client say he can accept more data, try to free our
1088                  * queues ASAP - Jean II */
1089                 irttp_run_rx_queue(self);
1090 
1091                 break;
1092         default:
1093                 IRDA_DEBUG(1, "%s(), Unknown flow command!\n", __func__);
1094         }
1095 }
1096 EXPORT_SYMBOL(irttp_flow_request);
1097 
1098 /*
1099  * Function irttp_connect_request (self, dtsap_sel, daddr, qos)
1100  *
1101  *    Try to connect to remote destination TSAP selector
1102  *
1103  */
1104 int irttp_connect_request(struct tsap_cb *self, __u8 dtsap_sel,
1105                           __u32 saddr, __u32 daddr,
1106                           struct qos_info *qos, __u32 max_sdu_size,
1107                           struct sk_buff *userdata)
1108 {
1109         struct sk_buff *tx_skb;
1110         __u8 *frame;
1111         __u8 n;
1112 
1113         IRDA_DEBUG(4, "%s(), max_sdu_size=%d\n", __func__, max_sdu_size);
1114 
1115         IRDA_ASSERT(self != NULL, return -EBADR;);
1116         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -EBADR;);
1117 
1118         if (self->connected) {
1119                 if(userdata)
1120                         dev_kfree_skb(userdata);
1121                 return -EISCONN;
1122         }
1123 
1124         /* Any userdata supplied? */
1125         if (userdata == NULL) {
1126                 tx_skb = alloc_skb(TTP_MAX_HEADER + TTP_SAR_HEADER,
1127                                    GFP_ATOMIC);
1128                 if (!tx_skb)
1129                         return -ENOMEM;
1130 
1131                 /* Reserve space for MUX_CONTROL and LAP header */
1132                 skb_reserve(tx_skb, TTP_MAX_HEADER + TTP_SAR_HEADER);
1133         } else {
1134                 tx_skb = userdata;
1135                 /*
1136                  *  Check that the client has reserved enough space for
1137                  *  headers
1138                  */
1139                 IRDA_ASSERT(skb_headroom(userdata) >= TTP_MAX_HEADER,
1140                         { dev_kfree_skb(userdata); return -1; } );
1141         }
1142 
1143         /* Initialize connection parameters */
1144         self->connected = FALSE;
1145         self->avail_credit = 0;
1146         self->rx_max_sdu_size = max_sdu_size;
1147         self->rx_sdu_size = 0;
1148         self->rx_sdu_busy = FALSE;
1149         self->dtsap_sel = dtsap_sel;
1150 
1151         n = self->initial_credit;
1152 
1153         self->remote_credit = 0;
1154         self->send_credit = 0;
1155 
1156         /*
1157          *  Give away max 127 credits for now
1158          */
1159         if (n > 127) {
1160                 self->avail_credit=n-127;
1161                 n = 127;
1162         }
1163 
1164         self->remote_credit = n;
1165 
1166         /* SAR enabled? */
1167         if (max_sdu_size > 0) {
1168                 IRDA_ASSERT(skb_headroom(tx_skb) >= (TTP_MAX_HEADER + TTP_SAR_HEADER),
1169                         { dev_kfree_skb(tx_skb); return -1; } );
1170 
1171                 /* Insert SAR parameters */
1172                 frame = skb_push(tx_skb, TTP_HEADER+TTP_SAR_HEADER);
1173 
1174                 frame[0] = TTP_PARAMETERS | n;
1175                 frame[1] = 0x04; /* Length */
1176                 frame[2] = 0x01; /* MaxSduSize */
1177                 frame[3] = 0x02; /* Value length */
1178 
1179                 put_unaligned(cpu_to_be16((__u16) max_sdu_size),
1180                               (__be16 *)(frame+4));
1181         } else {
1182                 /* Insert plain TTP header */
1183                 frame = skb_push(tx_skb, TTP_HEADER);
1184 
1185                 /* Insert initial credit in frame */
1186                 frame[0] = n & 0x7f;
1187         }
1188 
1189         /* Connect with IrLMP. No QoS parameters for now */
1190         return irlmp_connect_request(self->lsap, dtsap_sel, saddr, daddr, qos,
1191                                      tx_skb);
1192 }
1193 EXPORT_SYMBOL(irttp_connect_request);
1194 
1195 /*
1196  * Function irttp_connect_confirm (handle, qos, skb)
1197  *
1198  *    Service user confirms TSAP connection with peer.
1199  *
1200  */
1201 static void irttp_connect_confirm(void *instance, void *sap,
1202                                   struct qos_info *qos, __u32 max_seg_size,
1203                                   __u8 max_header_size, struct sk_buff *skb)
1204 {
1205         struct tsap_cb *self;
1206         int parameters;
1207         int ret;
1208         __u8 plen;
1209         __u8 n;
1210 
1211         IRDA_DEBUG(4, "%s()\n", __func__);
1212 
1213         self = instance;
1214 
1215         IRDA_ASSERT(self != NULL, return;);
1216         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1217         IRDA_ASSERT(skb != NULL, return;);
1218 
1219         self->max_seg_size = max_seg_size - TTP_HEADER;
1220         self->max_header_size = max_header_size + TTP_HEADER;
1221 
1222         /*
1223          *  Check if we have got some QoS parameters back! This should be the
1224          *  negotiated QoS for the link.
1225          */
1226         if (qos) {
1227                 IRDA_DEBUG(4, "IrTTP, Negotiated BAUD_RATE: %02x\n",
1228                        qos->baud_rate.bits);
1229                 IRDA_DEBUG(4, "IrTTP, Negotiated BAUD_RATE: %d bps.\n",
1230                        qos->baud_rate.value);
1231         }
1232 
1233         n = skb->data[0] & 0x7f;
1234 
1235         IRDA_DEBUG(4, "%s(), Initial send_credit=%d\n", __func__, n);
1236 
1237         self->send_credit = n;
1238         self->tx_max_sdu_size = 0;
1239         self->connected = TRUE;
1240 
1241         parameters = skb->data[0] & 0x80;
1242 
1243         IRDA_ASSERT(skb->len >= TTP_HEADER, return;);
1244         skb_pull(skb, TTP_HEADER);
1245 
1246         if (parameters) {
1247                 plen = skb->data[0];
1248 
1249                 ret = irda_param_extract_all(self, skb->data+1,
1250                                              IRDA_MIN(skb->len-1, plen),
1251                                              &param_info);
1252 
1253                 /* Any errors in the parameter list? */
1254                 if (ret < 0) {
1255                         IRDA_WARNING("%s: error extracting parameters\n",
1256                                      __func__);
1257                         dev_kfree_skb(skb);
1258 
1259                         /* Do not accept this connection attempt */
1260                         return;
1261                 }
1262                 /* Remove parameters */
1263                 skb_pull(skb, IRDA_MIN(skb->len, plen+1));
1264         }
1265 
1266         IRDA_DEBUG(4, "%s() send=%d,avail=%d,remote=%d\n", __func__,
1267               self->send_credit, self->avail_credit, self->remote_credit);
1268 
1269         IRDA_DEBUG(2, "%s(), MaxSduSize=%d\n", __func__,
1270                    self->tx_max_sdu_size);
1271 
1272         if (self->notify.connect_confirm) {
1273                 self->notify.connect_confirm(self->notify.instance, self, qos,
1274                                              self->tx_max_sdu_size,
1275                                              self->max_header_size, skb);
1276         } else
1277                 dev_kfree_skb(skb);
1278 }
1279 
1280 /*
1281  * Function irttp_connect_indication (handle, skb)
1282  *
1283  *    Some other device is connecting to this TSAP
1284  *
1285  */
1286 static void irttp_connect_indication(void *instance, void *sap,
1287                 struct qos_info *qos, __u32 max_seg_size, __u8 max_header_size,
1288                 struct sk_buff *skb)
1289 {
1290         struct tsap_cb *self;
1291         struct lsap_cb *lsap;
1292         int parameters;
1293         int ret;
1294         __u8 plen;
1295         __u8 n;
1296 
1297         self = instance;
1298 
1299         IRDA_ASSERT(self != NULL, return;);
1300         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1301         IRDA_ASSERT(skb != NULL, return;);
1302 
1303         lsap = sap;
1304 
1305         self->max_seg_size = max_seg_size - TTP_HEADER;
1306         self->max_header_size = max_header_size+TTP_HEADER;
1307 
1308         IRDA_DEBUG(4, "%s(), TSAP sel=%02x\n", __func__, self->stsap_sel);
1309 
1310         /* Need to update dtsap_sel if its equal to LSAP_ANY */
1311         self->dtsap_sel = lsap->dlsap_sel;
1312 
1313         n = skb->data[0] & 0x7f;
1314 
1315         self->send_credit = n;
1316         self->tx_max_sdu_size = 0;
1317 
1318         parameters = skb->data[0] & 0x80;
1319 
1320         IRDA_ASSERT(skb->len >= TTP_HEADER, return;);
1321         skb_pull(skb, TTP_HEADER);
1322 
1323         if (parameters) {
1324                 plen = skb->data[0];
1325 
1326                 ret = irda_param_extract_all(self, skb->data+1,
1327                                              IRDA_MIN(skb->len-1, plen),
1328                                              &param_info);
1329 
1330                 /* Any errors in the parameter list? */
1331                 if (ret < 0) {
1332                         IRDA_WARNING("%s: error extracting parameters\n",
1333                                      __func__);
1334                         dev_kfree_skb(skb);
1335 
1336                         /* Do not accept this connection attempt */
1337                         return;
1338                 }
1339 
1340                 /* Remove parameters */
1341                 skb_pull(skb, IRDA_MIN(skb->len, plen+1));
1342         }
1343 
1344         if (self->notify.connect_indication) {
1345                 self->notify.connect_indication(self->notify.instance, self,
1346                                                 qos, self->tx_max_sdu_size,
1347                                                 self->max_header_size, skb);
1348         } else
1349                 dev_kfree_skb(skb);
1350 }
1351 
1352 /*
1353  * Function irttp_connect_response (handle, userdata)
1354  *
1355  *    Service user is accepting the connection, just pass it down to
1356  *    IrLMP!
1357  *
1358  */
1359 int irttp_connect_response(struct tsap_cb *self, __u32 max_sdu_size,
1360                            struct sk_buff *userdata)
1361 {
1362         struct sk_buff *tx_skb;
1363         __u8 *frame;
1364         int ret;
1365         __u8 n;
1366 
1367         IRDA_ASSERT(self != NULL, return -1;);
1368         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
1369 
1370         IRDA_DEBUG(4, "%s(), Source TSAP selector=%02x\n", __func__,
1371                    self->stsap_sel);
1372 
1373         /* Any userdata supplied? */
1374         if (userdata == NULL) {
1375                 tx_skb = alloc_skb(TTP_MAX_HEADER + TTP_SAR_HEADER,
1376                                    GFP_ATOMIC);
1377                 if (!tx_skb)
1378                         return -ENOMEM;
1379 
1380                 /* Reserve space for MUX_CONTROL and LAP header */
1381                 skb_reserve(tx_skb, TTP_MAX_HEADER + TTP_SAR_HEADER);
1382         } else {
1383                 tx_skb = userdata;
1384                 /*
1385                  *  Check that the client has reserved enough space for
1386                  *  headers
1387                  */
1388                 IRDA_ASSERT(skb_headroom(userdata) >= TTP_MAX_HEADER,
1389                         { dev_kfree_skb(userdata); return -1; } );
1390         }
1391 
1392         self->avail_credit = 0;
1393         self->remote_credit = 0;
1394         self->rx_max_sdu_size = max_sdu_size;
1395         self->rx_sdu_size = 0;
1396         self->rx_sdu_busy = FALSE;
1397 
1398         n = self->initial_credit;
1399 
1400         /* Frame has only space for max 127 credits (7 bits) */
1401         if (n > 127) {
1402                 self->avail_credit = n - 127;
1403                 n = 127;
1404         }
1405 
1406         self->remote_credit = n;
1407         self->connected = TRUE;
1408 
1409         /* SAR enabled? */
1410         if (max_sdu_size > 0) {
1411                 IRDA_ASSERT(skb_headroom(tx_skb) >= (TTP_MAX_HEADER + TTP_SAR_HEADER),
1412                         { dev_kfree_skb(tx_skb); return -1; } );
1413 
1414                 /* Insert TTP header with SAR parameters */
1415                 frame = skb_push(tx_skb, TTP_HEADER+TTP_SAR_HEADER);
1416 
1417                 frame[0] = TTP_PARAMETERS | n;
1418                 frame[1] = 0x04; /* Length */
1419 
1420                 /* irda_param_insert(self, IRTTP_MAX_SDU_SIZE, frame+1,  */
1421 /*                                TTP_SAR_HEADER, &param_info) */
1422 
1423                 frame[2] = 0x01; /* MaxSduSize */
1424                 frame[3] = 0x02; /* Value length */
1425 
1426                 put_unaligned(cpu_to_be16((__u16) max_sdu_size),
1427                               (__be16 *)(frame+4));
1428         } else {
1429                 /* Insert TTP header */
1430                 frame = skb_push(tx_skb, TTP_HEADER);
1431 
1432                 frame[0] = n & 0x7f;
1433         }
1434 
1435         ret = irlmp_connect_response(self->lsap, tx_skb);
1436 
1437         return ret;
1438 }
1439 EXPORT_SYMBOL(irttp_connect_response);
1440 
1441 /*
1442  * Function irttp_dup (self, instance)
1443  *
1444  *    Duplicate TSAP, can be used by servers to confirm a connection on a
1445  *    new TSAP so it can keep listening on the old one.
1446  */
1447 struct tsap_cb *irttp_dup(struct tsap_cb *orig, void *instance)
1448 {
1449         struct tsap_cb *new;
1450         unsigned long flags;
1451 
1452         IRDA_DEBUG(1, "%s()\n", __func__);
1453 
1454         /* Protect our access to the old tsap instance */
1455         spin_lock_irqsave(&irttp->tsaps->hb_spinlock, flags);
1456 
1457         /* Find the old instance */
1458         if (!hashbin_find(irttp->tsaps, (long) orig, NULL)) {
1459                 IRDA_DEBUG(0, "%s(), unable to find TSAP\n", __func__);
1460                 spin_unlock_irqrestore(&irttp->tsaps->hb_spinlock, flags);
1461                 return NULL;
1462         }
1463 
1464         /* Allocate a new instance */
1465         new = kmemdup(orig, sizeof(struct tsap_cb), GFP_ATOMIC);
1466         if (!new) {
1467                 IRDA_DEBUG(0, "%s(), unable to kmalloc\n", __func__);
1468                 spin_unlock_irqrestore(&irttp->tsaps->hb_spinlock, flags);
1469                 return NULL;
1470         }
1471         spin_lock_init(&new->lock);
1472 
1473         /* We don't need the old instance any more */
1474         spin_unlock_irqrestore(&irttp->tsaps->hb_spinlock, flags);
1475 
1476         /* Try to dup the LSAP (may fail if we were too slow) */
1477         new->lsap = irlmp_dup(orig->lsap, new);
1478         if (!new->lsap) {
1479                 IRDA_DEBUG(0, "%s(), dup failed!\n", __func__);
1480                 kfree(new);
1481                 return NULL;
1482         }
1483 
1484         /* Not everything should be copied */
1485         new->notify.instance = instance;
1486 
1487         /* Initialize internal objects */
1488         irttp_init_tsap(new);
1489 
1490         /* This is locked */
1491         hashbin_insert(irttp->tsaps, (irda_queue_t *) new, (long) new, NULL);
1492 
1493         return new;
1494 }
1495 EXPORT_SYMBOL(irttp_dup);
1496 
1497 /*
1498  * Function irttp_disconnect_request (self)
1499  *
1500  *    Close this connection please! If priority is high, the queued data
1501  *    segments, if any, will be deallocated first
1502  *
1503  */
1504 int irttp_disconnect_request(struct tsap_cb *self, struct sk_buff *userdata,
1505                              int priority)
1506 {
1507         int ret;
1508 
1509         IRDA_ASSERT(self != NULL, return -1;);
1510         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
1511 
1512         /* Already disconnected? */
1513         if (!self->connected) {
1514                 IRDA_DEBUG(4, "%s(), already disconnected!\n", __func__);
1515                 if (userdata)
1516                         dev_kfree_skb(userdata);
1517                 return -1;
1518         }
1519 
1520         /* Disconnect already pending ?
1521          * We need to use an atomic operation to prevent reentry. This
1522          * function may be called from various context, like user, timer
1523          * for following a disconnect_indication() (i.e. net_bh).
1524          * Jean II */
1525         if(test_and_set_bit(0, &self->disconnect_pend)) {
1526                 IRDA_DEBUG(0, "%s(), disconnect already pending\n",
1527                            __func__);
1528                 if (userdata)
1529                         dev_kfree_skb(userdata);
1530 
1531                 /* Try to make some progress */
1532                 irttp_run_tx_queue(self);
1533                 return -1;
1534         }
1535 
1536         /*
1537          *  Check if there is still data segments in the transmit queue
1538          */
1539         if (!skb_queue_empty(&self->tx_queue)) {
1540                 if (priority == P_HIGH) {
1541                         /*
1542                          *  No need to send the queued data, if we are
1543                          *  disconnecting right now since the data will
1544                          *  not have any usable connection to be sent on
1545                          */
1546                         IRDA_DEBUG(1, "%s(): High priority!!()\n", __func__);
1547                         irttp_flush_queues(self);
1548                 } else if (priority == P_NORMAL) {
1549                         /*
1550                          *  Must delay disconnect until after all data segments
1551                          *  have been sent and the tx_queue is empty
1552                          */
1553                         /* We'll reuse this one later for the disconnect */
1554                         self->disconnect_skb = userdata;  /* May be NULL */
1555 
1556                         irttp_run_tx_queue(self);
1557 
1558                         irttp_start_todo_timer(self, HZ/10);
1559                         return -1;
1560                 }
1561         }
1562         /* Note : we don't need to check if self->rx_queue is full and the
1563          * state of self->rx_sdu_busy because the disconnect response will
1564          * be sent at the LMP level (so even if the peer has its Tx queue
1565          * full of data). - Jean II */
1566 
1567         IRDA_DEBUG(1, "%s(), Disconnecting ...\n", __func__);
1568         self->connected = FALSE;
1569 
1570         if (!userdata) {
1571                 struct sk_buff *tx_skb;
1572                 tx_skb = alloc_skb(LMP_MAX_HEADER, GFP_ATOMIC);
1573                 if (!tx_skb)
1574                         return -ENOMEM;
1575 
1576                 /*
1577                  *  Reserve space for MUX and LAP header
1578                  */
1579                 skb_reserve(tx_skb, LMP_MAX_HEADER);
1580 
1581                 userdata = tx_skb;
1582         }
1583         ret = irlmp_disconnect_request(self->lsap, userdata);
1584 
1585         /* The disconnect is no longer pending */
1586         clear_bit(0, &self->disconnect_pend);   /* FALSE */
1587 
1588         return ret;
1589 }
1590 EXPORT_SYMBOL(irttp_disconnect_request);
1591 
1592 /*
1593  * Function irttp_disconnect_indication (self, reason)
1594  *
1595  *    Disconnect indication, TSAP disconnected by peer?
1596  *
1597  */
1598 static void irttp_disconnect_indication(void *instance, void *sap,
1599                 LM_REASON reason, struct sk_buff *skb)
1600 {
1601         struct tsap_cb *self;
1602 
1603         IRDA_DEBUG(4, "%s()\n", __func__);
1604 
1605         self = instance;
1606 
1607         IRDA_ASSERT(self != NULL, return;);
1608         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1609 
1610         /* Prevent higher layer to send more data */
1611         self->connected = FALSE;
1612 
1613         /* Check if client has already tried to close the TSAP */
1614         if (self->close_pend) {
1615                 /* In this case, the higher layer is probably gone. Don't
1616                  * bother it and clean up the remains - Jean II */
1617                 if (skb)
1618                         dev_kfree_skb(skb);
1619                 irttp_close_tsap(self);
1620                 return;
1621         }
1622 
1623         /* If we are here, we assume that is the higher layer is still
1624          * waiting for the disconnect notification and able to process it,
1625          * even if he tried to disconnect. Otherwise, it would have already
1626          * attempted to close the tsap and self->close_pend would be TRUE.
1627          * Jean II */
1628 
1629         /* No need to notify the client if has already tried to disconnect */
1630         if(self->notify.disconnect_indication)
1631                 self->notify.disconnect_indication(self->notify.instance, self,
1632                                                    reason, skb);
1633         else
1634                 if (skb)
1635                         dev_kfree_skb(skb);
1636 }
1637 
1638 /*
1639  * Function irttp_do_data_indication (self, skb)
1640  *
1641  *    Try to deliver reassembled skb to layer above, and requeue it if that
1642  *    for some reason should fail. We mark rx sdu as busy to apply back
1643  *    pressure is necessary.
1644  */
1645 static void irttp_do_data_indication(struct tsap_cb *self, struct sk_buff *skb)
1646 {
1647         int err;
1648 
1649         /* Check if client has already closed the TSAP and gone away */
1650         if (self->close_pend) {
1651                 dev_kfree_skb(skb);
1652                 return;
1653         }
1654 
1655         err = self->notify.data_indication(self->notify.instance, self, skb);
1656 
1657         /* Usually the layer above will notify that it's input queue is
1658          * starting to get filled by using the flow request, but this may
1659          * be difficult, so it can instead just refuse to eat it and just
1660          * give an error back
1661          */
1662         if (err) {
1663                 IRDA_DEBUG(0, "%s() requeueing skb!\n", __func__);
1664 
1665                 /* Make sure we take a break */
1666                 self->rx_sdu_busy = TRUE;
1667 
1668                 /* Need to push the header in again */
1669                 skb_push(skb, TTP_HEADER);
1670                 skb->data[0] = 0x00; /* Make sure MORE bit is cleared */
1671 
1672                 /* Put skb back on queue */
1673                 skb_queue_head(&self->rx_queue, skb);
1674         }
1675 }
1676 
1677 /*
1678  * Function irttp_run_rx_queue (self)
1679  *
1680  *     Check if we have any frames to be transmitted, or if we have any
1681  *     available credit to give away.
1682  */
1683 static void irttp_run_rx_queue(struct tsap_cb *self)
1684 {
1685         struct sk_buff *skb;
1686         int more = 0;
1687 
1688         IRDA_DEBUG(2, "%s() send=%d,avail=%d,remote=%d\n", __func__,
1689                    self->send_credit, self->avail_credit, self->remote_credit);
1690 
1691         /* Get exclusive access to the rx queue, otherwise don't touch it */
1692         if (irda_lock(&self->rx_queue_lock) == FALSE)
1693                 return;
1694 
1695         /*
1696          *  Reassemble all frames in receive queue and deliver them
1697          */
1698         while (!self->rx_sdu_busy && (skb = skb_dequeue(&self->rx_queue))) {
1699                 /* This bit will tell us if it's the last fragment or not */
1700                 more = skb->data[0] & 0x80;
1701 
1702                 /* Remove TTP header */
1703                 skb_pull(skb, TTP_HEADER);
1704 
1705                 /* Add the length of the remaining data */
1706                 self->rx_sdu_size += skb->len;
1707 
1708                 /*
1709                  * If SAR is disabled, or user has requested no reassembly
1710                  * of received fragments then we just deliver them
1711                  * immediately. This can be requested by clients that
1712                  * implements byte streams without any message boundaries
1713                  */
1714                 if (self->rx_max_sdu_size == TTP_SAR_DISABLE) {
1715                         irttp_do_data_indication(self, skb);
1716                         self->rx_sdu_size = 0;
1717 
1718                         continue;
1719                 }
1720 
1721                 /* Check if this is a fragment, and not the last fragment */
1722                 if (more) {
1723                         /*
1724                          *  Queue the fragment if we still are within the
1725                          *  limits of the maximum size of the rx_sdu
1726                          */
1727                         if (self->rx_sdu_size <= self->rx_max_sdu_size) {
1728                                 IRDA_DEBUG(4, "%s(), queueing frag\n",
1729                                            __func__);
1730                                 skb_queue_tail(&self->rx_fragments, skb);
1731                         } else {
1732                                 /* Free the part of the SDU that is too big */
1733                                 dev_kfree_skb(skb);
1734                         }
1735                         continue;
1736                 }
1737                 /*
1738                  *  This is the last fragment, so time to reassemble!
1739                  */
1740                 if ((self->rx_sdu_size <= self->rx_max_sdu_size) ||
1741                     (self->rx_max_sdu_size == TTP_SAR_UNBOUND))
1742                 {
1743                         /*
1744                          * A little optimizing. Only queue the fragment if
1745                          * there are other fragments. Since if this is the
1746                          * last and only fragment, there is no need to
1747                          * reassemble :-)
1748                          */
1749                         if (!skb_queue_empty(&self->rx_fragments)) {
1750                                 skb_queue_tail(&self->rx_fragments,
1751                                                skb);
1752 
1753                                 skb = irttp_reassemble_skb(self);
1754                         }
1755 
1756                         /* Now we can deliver the reassembled skb */
1757                         irttp_do_data_indication(self, skb);
1758                 } else {
1759                         IRDA_DEBUG(1, "%s(), Truncated frame\n", __func__);
1760 
1761                         /* Free the part of the SDU that is too big */
1762                         dev_kfree_skb(skb);
1763 
1764                         /* Deliver only the valid but truncated part of SDU */
1765                         skb = irttp_reassemble_skb(self);
1766 
1767                         irttp_do_data_indication(self, skb);
1768                 }
1769                 self->rx_sdu_size = 0;
1770         }
1771 
1772         /*
1773          * It's not trivial to keep track of how many credits are available
1774          * by incrementing at each packet, because delivery may fail
1775          * (irttp_do_data_indication() may requeue the frame) and because
1776          * we need to take care of fragmentation.
1777          * We want the other side to send up to initial_credit packets.
1778          * We have some frames in our queues, and we have already allowed it
1779          * to send remote_credit.
1780          * No need to spinlock, write is atomic and self correcting...
1781          * Jean II
1782          */
1783         self->avail_credit = (self->initial_credit -
1784                               (self->remote_credit +
1785                                skb_queue_len(&self->rx_queue) +
1786                                skb_queue_len(&self->rx_fragments)));
1787 
1788         /* Do we have too much credits to send to peer ? */
1789         if ((self->remote_credit <= TTP_RX_MIN_CREDIT) &&
1790             (self->avail_credit > 0)) {
1791                 /* Send explicit credit frame */
1792                 irttp_give_credit(self);
1793                 /* Note : do *NOT* check if tx_queue is non-empty, that
1794                  * will produce deadlocks. I repeat : send a credit frame
1795                  * even if we have something to send in our Tx queue.
1796                  * If we have credits, it means that our Tx queue is blocked.
1797                  *
1798                  * Let's suppose the peer can't keep up with our Tx. He will
1799                  * flow control us by not sending us any credits, and we
1800                  * will stop Tx and start accumulating credits here.
1801                  * Up to the point where the peer will stop its Tx queue,
1802                  * for lack of credits.
1803                  * Let's assume the peer application is single threaded.
1804                  * It will block on Tx and never consume any Rx buffer.
1805                  * Deadlock. Guaranteed. - Jean II
1806                  */
1807         }
1808 
1809         /* Reset lock */
1810         self->rx_queue_lock = 0;
1811 }
1812 
1813 #ifdef CONFIG_PROC_FS
1814 struct irttp_iter_state {
1815         int id;
1816 };
1817 
1818 static void *irttp_seq_start(struct seq_file *seq, loff_t *pos)
1819 {
1820         struct irttp_iter_state *iter = seq->private;
1821         struct tsap_cb *self;
1822 
1823         /* Protect our access to the tsap list */
1824         spin_lock_irq(&irttp->tsaps->hb_spinlock);
1825         iter->id = 0;
1826 
1827         for (self = (struct tsap_cb *) hashbin_get_first(irttp->tsaps);
1828              self != NULL;
1829              self = (struct tsap_cb *) hashbin_get_next(irttp->tsaps)) {
1830                 if (iter->id == *pos)
1831                         break;
1832                 ++iter->id;
1833         }
1834 
1835         return self;
1836 }
1837 
1838 static void *irttp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1839 {
1840         struct irttp_iter_state *iter = seq->private;
1841 
1842         ++*pos;
1843         ++iter->id;
1844         return (void *) hashbin_get_next(irttp->tsaps);
1845 }
1846 
1847 static void irttp_seq_stop(struct seq_file *seq, void *v)
1848 {
1849         spin_unlock_irq(&irttp->tsaps->hb_spinlock);
1850 }
1851 
1852 static int irttp_seq_show(struct seq_file *seq, void *v)
1853 {
1854         const struct irttp_iter_state *iter = seq->private;
1855         const struct tsap_cb *self = v;
1856 
1857         seq_printf(seq, "TSAP %d, ", iter->id);
1858         seq_printf(seq, "stsap_sel: %02x, ",
1859                    self->stsap_sel);
1860         seq_printf(seq, "dtsap_sel: %02x\n",
1861                    self->dtsap_sel);
1862         seq_printf(seq, "  connected: %s, ",
1863                    self->connected? "TRUE":"FALSE");
1864         seq_printf(seq, "avail credit: %d, ",
1865                    self->avail_credit);
1866         seq_printf(seq, "remote credit: %d, ",
1867                    self->remote_credit);
1868         seq_printf(seq, "send credit: %d\n",
1869                    self->send_credit);
1870         seq_printf(seq, "  tx packets: %lu, ",
1871                    self->stats.tx_packets);
1872         seq_printf(seq, "rx packets: %lu, ",
1873                    self->stats.rx_packets);
1874         seq_printf(seq, "tx_queue len: %u ",
1875                    skb_queue_len(&self->tx_queue));
1876         seq_printf(seq, "rx_queue len: %u\n",
1877                    skb_queue_len(&self->rx_queue));
1878         seq_printf(seq, "  tx_sdu_busy: %s, ",
1879                    self->tx_sdu_busy? "TRUE":"FALSE");
1880         seq_printf(seq, "rx_sdu_busy: %s\n",
1881                    self->rx_sdu_busy? "TRUE":"FALSE");
1882         seq_printf(seq, "  max_seg_size: %u, ",
1883                    self->max_seg_size);
1884         seq_printf(seq, "tx_max_sdu_size: %u, ",
1885                    self->tx_max_sdu_size);
1886         seq_printf(seq, "rx_max_sdu_size: %u\n",
1887                    self->rx_max_sdu_size);
1888 
1889         seq_printf(seq, "  Used by (%s)\n\n",
1890                    self->notify.name);
1891         return 0;
1892 }
1893 
1894 static const struct seq_operations irttp_seq_ops = {
1895         .start  = irttp_seq_start,
1896         .next   = irttp_seq_next,
1897         .stop   = irttp_seq_stop,
1898         .show   = irttp_seq_show,
1899 };
1900 
1901 static int irttp_seq_open(struct inode *inode, struct file *file)
1902 {
1903         return seq_open_private(file, &irttp_seq_ops,
1904                         sizeof(struct irttp_iter_state));
1905 }
1906 
1907 const struct file_operations irttp_seq_fops = {
1908         .owner          = THIS_MODULE,
1909         .open           = irttp_seq_open,
1910         .read           = seq_read,
1911         .llseek         = seq_lseek,
1912         .release        = seq_release_private,
1913 };
1914 
1915 #endif /* PROC_FS */
1916 

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