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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                 IRDA_ERROR("%s: SAR enabled, but data is larger than TxMaxSduSize!\n",
644                            __func__);
645                 ret = -EMSGSIZE;
646                 goto err;
647         }
648         /*
649          *  Check if transmit queue is full
650          */
651         if (skb_queue_len(&self->tx_queue) >= TTP_TX_MAX_QUEUE) {
652                 /*
653                  *  Give it a chance to empty itself
654                  */
655                 irttp_run_tx_queue(self);
656 
657                 /* Drop packet. This error code should trigger the caller
658                  * to resend the data in the client code - Jean II */
659                 ret = -ENOBUFS;
660                 goto err;
661         }
662 
663         /* Queue frame, or queue frame segments */
664         if ((self->tx_max_sdu_size == 0) || (skb->len < self->max_seg_size)) {
665                 /* Queue frame */
666                 IRDA_ASSERT(skb_headroom(skb) >= TTP_HEADER, return -1;);
667                 frame = skb_push(skb, TTP_HEADER);
668                 frame[0] = 0x00; /* Clear more bit */
669 
670                 skb_queue_tail(&self->tx_queue, skb);
671         } else {
672                 /*
673                  *  Fragment the frame, this function will also queue the
674                  *  fragments, we don't care about the fact the transmit
675                  *  queue may be overfilled by all the segments for a little
676                  *  while
677                  */
678                 irttp_fragment_skb(self, skb);
679         }
680 
681         /* Check if we can accept more data from client */
682         if ((!self->tx_sdu_busy) &&
683             (skb_queue_len(&self->tx_queue) > TTP_TX_HIGH_THRESHOLD)) {
684                 /* Tx queue filling up, so stop client. */
685                 if (self->notify.flow_indication) {
686                         self->notify.flow_indication(self->notify.instance,
687                                                      self, FLOW_STOP);
688                 }
689                 /* self->tx_sdu_busy is the state of the client.
690                  * Update state after notifying client to avoid
691                  * race condition with irttp_flow_indication().
692                  * If the queue empty itself after our test but before
693                  * we set the flag, we will fix ourselves below in
694                  * irttp_run_tx_queue().
695                  * Jean II */
696                 self->tx_sdu_busy = TRUE;
697         }
698 
699         /* Try to make some progress */
700         irttp_run_tx_queue(self);
701 
702         return 0;
703 
704 err:
705         dev_kfree_skb(skb);
706         return ret;
707 }
708 EXPORT_SYMBOL(irttp_data_request);
709 
710 /*
711  * Function irttp_run_tx_queue (self)
712  *
713  *    Transmit packets queued for transmission (if possible)
714  *
715  */
716 static void irttp_run_tx_queue(struct tsap_cb *self)
717 {
718         struct sk_buff *skb;
719         unsigned long flags;
720         int n;
721 
722         IRDA_DEBUG(2, "%s() : send_credit = %d, queue_len = %d\n",
723                    __func__,
724                    self->send_credit, skb_queue_len(&self->tx_queue));
725 
726         /* Get exclusive access to the tx queue, otherwise don't touch it */
727         if (irda_lock(&self->tx_queue_lock) == FALSE)
728                 return;
729 
730         /* Try to send out frames as long as we have credits
731          * and as long as LAP is not full. If LAP is full, it will
732          * poll us through irttp_flow_indication() - Jean II */
733         while ((self->send_credit > 0) &&
734                (!irlmp_lap_tx_queue_full(self->lsap)) &&
735                (skb = skb_dequeue(&self->tx_queue))) {
736                 /*
737                  *  Since we can transmit and receive frames concurrently,
738                  *  the code below is a critical region and we must assure that
739                  *  nobody messes with the credits while we update them.
740                  */
741                 spin_lock_irqsave(&self->lock, flags);
742 
743                 n = self->avail_credit;
744                 self->avail_credit = 0;
745 
746                 /* Only room for 127 credits in frame */
747                 if (n > 127) {
748                         self->avail_credit = n-127;
749                         n = 127;
750                 }
751                 self->remote_credit += n;
752                 self->send_credit--;
753 
754                 spin_unlock_irqrestore(&self->lock, flags);
755 
756                 /*
757                  *  More bit must be set by the data_request() or fragment()
758                  *  functions
759                  */
760                 skb->data[0] |= (n & 0x7f);
761 
762                 /* Detach from socket.
763                  * The current skb has a reference to the socket that sent
764                  * it (skb->sk). When we pass it to IrLMP, the skb will be
765                  * stored in in IrLAP (self->wx_list). When we are within
766                  * IrLAP, we lose the notion of socket, so we should not
767                  * have a reference to a socket. So, we drop it here.
768                  *
769                  * Why does it matter ?
770                  * When the skb is freed (kfree_skb), if it is associated
771                  * with a socket, it release buffer space on the socket
772                  * (through sock_wfree() and sock_def_write_space()).
773                  * If the socket no longer exist, we may crash. Hard.
774                  * When we close a socket, we make sure that associated packets
775                  * in IrTTP are freed. However, we have no way to cancel
776                  * the packet that we have passed to IrLAP. So, if a packet
777                  * remains in IrLAP (retry on the link or else) after we
778                  * close the socket, we are dead !
779                  * Jean II */
780                 if (skb->sk != NULL) {
781                         /* IrSOCK application, IrOBEX, ... */
782                         skb_orphan(skb);
783                 }
784                         /* IrCOMM over IrTTP, IrLAN, ... */
785 
786                 /* Pass the skb to IrLMP - done */
787                 irlmp_data_request(self->lsap, skb);
788                 self->stats.tx_packets++;
789         }
790 
791         /* Check if we can accept more frames from client.
792          * We don't want to wait until the todo timer to do that, and we
793          * can't use tasklets (grr...), so we are obliged to give control
794          * to client. That's ok, this test will be true not too often
795          * (max once per LAP window) and we are called from places
796          * where we can spend a bit of time doing stuff. - Jean II */
797         if ((self->tx_sdu_busy) &&
798             (skb_queue_len(&self->tx_queue) < TTP_TX_LOW_THRESHOLD) &&
799             (!self->close_pend)) {
800                 if (self->notify.flow_indication)
801                         self->notify.flow_indication(self->notify.instance,
802                                                      self, FLOW_START);
803 
804                 /* self->tx_sdu_busy is the state of the client.
805                  * We don't really have a race here, but it's always safer
806                  * to update our state after the client - Jean II */
807                 self->tx_sdu_busy = FALSE;
808         }
809 
810         /* Reset lock */
811         self->tx_queue_lock = 0;
812 }
813 
814 /*
815  * Function irttp_give_credit (self)
816  *
817  *    Send a dataless flowdata TTP-PDU and give available credit to peer
818  *    TSAP
819  */
820 static inline void irttp_give_credit(struct tsap_cb *self)
821 {
822         struct sk_buff *tx_skb = NULL;
823         unsigned long flags;
824         int n;
825 
826         IRDA_ASSERT(self != NULL, return;);
827         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
828 
829         IRDA_DEBUG(4, "%s() send=%d,avail=%d,remote=%d\n",
830                    __func__,
831                    self->send_credit, self->avail_credit, self->remote_credit);
832 
833         /* Give credit to peer */
834         tx_skb = alloc_skb(TTP_MAX_HEADER, GFP_ATOMIC);
835         if (!tx_skb)
836                 return;
837 
838         /* Reserve space for LMP, and LAP header */
839         skb_reserve(tx_skb, LMP_MAX_HEADER);
840 
841         /*
842          *  Since we can transmit and receive frames concurrently,
843          *  the code below is a critical region and we must assure that
844          *  nobody messes with the credits while we update them.
845          */
846         spin_lock_irqsave(&self->lock, flags);
847 
848         n = self->avail_credit;
849         self->avail_credit = 0;
850 
851         /* Only space for 127 credits in frame */
852         if (n > 127) {
853                 self->avail_credit = n - 127;
854                 n = 127;
855         }
856         self->remote_credit += n;
857 
858         spin_unlock_irqrestore(&self->lock, flags);
859 
860         skb_put(tx_skb, 1);
861         tx_skb->data[0] = (__u8) (n & 0x7f);
862 
863         irlmp_data_request(self->lsap, tx_skb);
864         self->stats.tx_packets++;
865 }
866 
867 /*
868  * Function irttp_udata_indication (instance, sap, skb)
869  *
870  *    Received some unit-data (unreliable)
871  *
872  */
873 static int irttp_udata_indication(void *instance, void *sap,
874                                   struct sk_buff *skb)
875 {
876         struct tsap_cb *self;
877         int err;
878 
879         IRDA_DEBUG(4, "%s()\n", __func__);
880 
881         self = instance;
882 
883         IRDA_ASSERT(self != NULL, return -1;);
884         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
885         IRDA_ASSERT(skb != NULL, return -1;);
886 
887         self->stats.rx_packets++;
888 
889         /* Just pass data to layer above */
890         if (self->notify.udata_indication) {
891                 err = self->notify.udata_indication(self->notify.instance,
892                                                     self, skb);
893                 /* Same comment as in irttp_do_data_indication() */
894                 if (!err)
895                         return 0;
896         }
897         /* Either no handler, or handler returns an error */
898         dev_kfree_skb(skb);
899 
900         return 0;
901 }
902 
903 /*
904  * Function irttp_data_indication (instance, sap, skb)
905  *
906  *    Receive segment from IrLMP.
907  *
908  */
909 static int irttp_data_indication(void *instance, void *sap,
910                                  struct sk_buff *skb)
911 {
912         struct tsap_cb *self;
913         unsigned long flags;
914         int n;
915 
916         self = instance;
917 
918         n = skb->data[0] & 0x7f;     /* Extract the credits */
919 
920         self->stats.rx_packets++;
921 
922         /*  Deal with inbound credit
923          *  Since we can transmit and receive frames concurrently,
924          *  the code below is a critical region and we must assure that
925          *  nobody messes with the credits while we update them.
926          */
927         spin_lock_irqsave(&self->lock, flags);
928         self->send_credit += n;
929         if (skb->len > 1)
930                 self->remote_credit--;
931         spin_unlock_irqrestore(&self->lock, flags);
932 
933         /*
934          *  Data or dataless packet? Dataless frames contains only the
935          *  TTP_HEADER.
936          */
937         if (skb->len > 1) {
938                 /*
939                  *  We don't remove the TTP header, since we must preserve the
940                  *  more bit, so the defragment routing knows what to do
941                  */
942                 skb_queue_tail(&self->rx_queue, skb);
943         } else {
944                 /* Dataless flowdata TTP-PDU */
945                 dev_kfree_skb(skb);
946         }
947 
948 
949         /* Push data to the higher layer.
950          * We do it synchronously because running the todo timer for each
951          * receive packet would be too much overhead and latency.
952          * By passing control to the higher layer, we run the risk that
953          * it may take time or grab a lock. Most often, the higher layer
954          * will only put packet in a queue.
955          * Anyway, packets are only dripping through the IrDA, so we can
956          * have time before the next packet.
957          * Further, we are run from NET_BH, so the worse that can happen is
958          * us missing the optimal time to send back the PF bit in LAP.
959          * Jean II */
960         irttp_run_rx_queue(self);
961 
962         /* We now give credits to peer in irttp_run_rx_queue().
963          * We need to send credit *NOW*, otherwise we are going
964          * to miss the next Tx window. The todo timer may take
965          * a while before it's run... - Jean II */
966 
967         /*
968          * If the peer device has given us some credits and we didn't have
969          * anyone from before, then we need to shedule the tx queue.
970          * We need to do that because our Tx have stopped (so we may not
971          * get any LAP flow indication) and the user may be stopped as
972          * well. - Jean II
973          */
974         if (self->send_credit == n) {
975                 /* Restart pushing stuff to LAP */
976                 irttp_run_tx_queue(self);
977                 /* Note : we don't want to schedule the todo timer
978                  * because it has horrible latency. No tasklets
979                  * because the tasklet API is broken. - Jean II */
980         }
981 
982         return 0;
983 }
984 
985 /*
986  * Function irttp_status_indication (self, reason)
987  *
988  *    Status_indication, just pass to the higher layer...
989  *
990  */
991 static void irttp_status_indication(void *instance,
992                                     LINK_STATUS link, LOCK_STATUS lock)
993 {
994         struct tsap_cb *self;
995 
996         IRDA_DEBUG(4, "%s()\n", __func__);
997 
998         self = instance;
999 
1000         IRDA_ASSERT(self != NULL, return;);
1001         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1002 
1003         /* Check if client has already closed the TSAP and gone away */
1004         if (self->close_pend)
1005                 return;
1006 
1007         /*
1008          *  Inform service user if he has requested it
1009          */
1010         if (self->notify.status_indication != NULL)
1011                 self->notify.status_indication(self->notify.instance,
1012                                                link, lock);
1013         else
1014                 IRDA_DEBUG(2, "%s(), no handler\n", __func__);
1015 }
1016 
1017 /*
1018  * Function irttp_flow_indication (self, reason)
1019  *
1020  *    Flow_indication : IrLAP tells us to send more data.
1021  *
1022  */
1023 static void irttp_flow_indication(void *instance, void *sap, LOCAL_FLOW flow)
1024 {
1025         struct tsap_cb *self;
1026 
1027         self = instance;
1028 
1029         IRDA_ASSERT(self != NULL, return;);
1030         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1031 
1032         IRDA_DEBUG(4, "%s(instance=%p)\n", __func__, self);
1033 
1034         /* We are "polled" directly from LAP, and the LAP want to fill
1035          * its Tx window. We want to do our best to send it data, so that
1036          * we maximise the window. On the other hand, we want to limit the
1037          * amount of work here so that LAP doesn't hang forever waiting
1038          * for packets. - Jean II */
1039 
1040         /* Try to send some packets. Currently, LAP calls us every time
1041          * there is one free slot, so we will send only one packet.
1042          * This allow the scheduler to do its round robin - Jean II */
1043         irttp_run_tx_queue(self);
1044 
1045         /* Note regarding the interraction with higher layer.
1046          * irttp_run_tx_queue() may call the client when its queue
1047          * start to empty, via notify.flow_indication(). Initially.
1048          * I wanted this to happen in a tasklet, to avoid client
1049          * grabbing the CPU, but we can't use tasklets safely. And timer
1050          * is definitely too slow.
1051          * This will happen only once per LAP window, and usually at
1052          * the third packet (unless window is smaller). LAP is still
1053          * doing mtt and sending first packet so it's sort of OK
1054          * to do that. Jean II */
1055 
1056         /* If we need to send disconnect. try to do it now */
1057         if (self->disconnect_pend)
1058                 irttp_start_todo_timer(self, 0);
1059 }
1060 
1061 /*
1062  * Function irttp_flow_request (self, command)
1063  *
1064  *    This function could be used by the upper layers to tell IrTTP to stop
1065  *    delivering frames if the receive queues are starting to get full, or
1066  *    to tell IrTTP to start delivering frames again.
1067  */
1068 void irttp_flow_request(struct tsap_cb *self, LOCAL_FLOW flow)
1069 {
1070         IRDA_DEBUG(1, "%s()\n", __func__);
1071 
1072         IRDA_ASSERT(self != NULL, return;);
1073         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1074 
1075         switch (flow) {
1076         case FLOW_STOP:
1077                 IRDA_DEBUG(1, "%s(), flow stop\n", __func__);
1078                 self->rx_sdu_busy = TRUE;
1079                 break;
1080         case FLOW_START:
1081                 IRDA_DEBUG(1, "%s(), flow start\n", __func__);
1082                 self->rx_sdu_busy = FALSE;
1083 
1084                 /* Client say he can accept more data, try to free our
1085                  * queues ASAP - Jean II */
1086                 irttp_run_rx_queue(self);
1087 
1088                 break;
1089         default:
1090                 IRDA_DEBUG(1, "%s(), Unknown flow command!\n", __func__);
1091         }
1092 }
1093 EXPORT_SYMBOL(irttp_flow_request);
1094 
1095 /*
1096  * Function irttp_connect_request (self, dtsap_sel, daddr, qos)
1097  *
1098  *    Try to connect to remote destination TSAP selector
1099  *
1100  */
1101 int irttp_connect_request(struct tsap_cb *self, __u8 dtsap_sel,
1102                           __u32 saddr, __u32 daddr,
1103                           struct qos_info *qos, __u32 max_sdu_size,
1104                           struct sk_buff *userdata)
1105 {
1106         struct sk_buff *tx_skb;
1107         __u8 *frame;
1108         __u8 n;
1109 
1110         IRDA_DEBUG(4, "%s(), max_sdu_size=%d\n", __func__, max_sdu_size);
1111 
1112         IRDA_ASSERT(self != NULL, return -EBADR;);
1113         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -EBADR;);
1114 
1115         if (self->connected) {
1116                 if (userdata)
1117                         dev_kfree_skb(userdata);
1118                 return -EISCONN;
1119         }
1120 
1121         /* Any userdata supplied? */
1122         if (userdata == NULL) {
1123                 tx_skb = alloc_skb(TTP_MAX_HEADER + TTP_SAR_HEADER,
1124                                    GFP_ATOMIC);
1125                 if (!tx_skb)
1126                         return -ENOMEM;
1127 
1128                 /* Reserve space for MUX_CONTROL and LAP header */
1129                 skb_reserve(tx_skb, TTP_MAX_HEADER + TTP_SAR_HEADER);
1130         } else {
1131                 tx_skb = userdata;
1132                 /*
1133                  *  Check that the client has reserved enough space for
1134                  *  headers
1135                  */
1136                 IRDA_ASSERT(skb_headroom(userdata) >= TTP_MAX_HEADER,
1137                         { dev_kfree_skb(userdata); return -1; });
1138         }
1139 
1140         /* Initialize connection parameters */
1141         self->connected = FALSE;
1142         self->avail_credit = 0;
1143         self->rx_max_sdu_size = max_sdu_size;
1144         self->rx_sdu_size = 0;
1145         self->rx_sdu_busy = FALSE;
1146         self->dtsap_sel = dtsap_sel;
1147 
1148         n = self->initial_credit;
1149 
1150         self->remote_credit = 0;
1151         self->send_credit = 0;
1152 
1153         /*
1154          *  Give away max 127 credits for now
1155          */
1156         if (n > 127) {
1157                 self->avail_credit = n - 127;
1158                 n = 127;
1159         }
1160 
1161         self->remote_credit = n;
1162 
1163         /* SAR enabled? */
1164         if (max_sdu_size > 0) {
1165                 IRDA_ASSERT(skb_headroom(tx_skb) >= (TTP_MAX_HEADER + TTP_SAR_HEADER),
1166                         { dev_kfree_skb(tx_skb); return -1; });
1167 
1168                 /* Insert SAR parameters */
1169                 frame = skb_push(tx_skb, TTP_HEADER + TTP_SAR_HEADER);
1170 
1171                 frame[0] = TTP_PARAMETERS | n;
1172                 frame[1] = 0x04; /* Length */
1173                 frame[2] = 0x01; /* MaxSduSize */
1174                 frame[3] = 0x02; /* Value length */
1175 
1176                 put_unaligned(cpu_to_be16((__u16) max_sdu_size),
1177                               (__be16 *)(frame+4));
1178         } else {
1179                 /* Insert plain TTP header */
1180                 frame = skb_push(tx_skb, TTP_HEADER);
1181 
1182                 /* Insert initial credit in frame */
1183                 frame[0] = n & 0x7f;
1184         }
1185 
1186         /* Connect with IrLMP. No QoS parameters for now */
1187         return irlmp_connect_request(self->lsap, dtsap_sel, saddr, daddr, qos,
1188                                      tx_skb);
1189 }
1190 EXPORT_SYMBOL(irttp_connect_request);
1191 
1192 /*
1193  * Function irttp_connect_confirm (handle, qos, skb)
1194  *
1195  *    Service user confirms TSAP connection with peer.
1196  *
1197  */
1198 static void irttp_connect_confirm(void *instance, void *sap,
1199                                   struct qos_info *qos, __u32 max_seg_size,
1200                                   __u8 max_header_size, struct sk_buff *skb)
1201 {
1202         struct tsap_cb *self;
1203         int parameters;
1204         int ret;
1205         __u8 plen;
1206         __u8 n;
1207 
1208         IRDA_DEBUG(4, "%s()\n", __func__);
1209 
1210         self = instance;
1211 
1212         IRDA_ASSERT(self != NULL, return;);
1213         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1214         IRDA_ASSERT(skb != NULL, return;);
1215 
1216         self->max_seg_size = max_seg_size - TTP_HEADER;
1217         self->max_header_size = max_header_size + TTP_HEADER;
1218 
1219         /*
1220          *  Check if we have got some QoS parameters back! This should be the
1221          *  negotiated QoS for the link.
1222          */
1223         if (qos) {
1224                 IRDA_DEBUG(4, "IrTTP, Negotiated BAUD_RATE: %02x\n",
1225                        qos->baud_rate.bits);
1226                 IRDA_DEBUG(4, "IrTTP, Negotiated BAUD_RATE: %d bps.\n",
1227                        qos->baud_rate.value);
1228         }
1229 
1230         n = skb->data[0] & 0x7f;
1231 
1232         IRDA_DEBUG(4, "%s(), Initial send_credit=%d\n", __func__, n);
1233 
1234         self->send_credit = n;
1235         self->tx_max_sdu_size = 0;
1236         self->connected = TRUE;
1237 
1238         parameters = skb->data[0] & 0x80;
1239 
1240         IRDA_ASSERT(skb->len >= TTP_HEADER, return;);
1241         skb_pull(skb, TTP_HEADER);
1242 
1243         if (parameters) {
1244                 plen = skb->data[0];
1245 
1246                 ret = irda_param_extract_all(self, skb->data+1,
1247                                              IRDA_MIN(skb->len-1, plen),
1248                                              &param_info);
1249 
1250                 /* Any errors in the parameter list? */
1251                 if (ret < 0) {
1252                         IRDA_WARNING("%s: error extracting parameters\n",
1253                                      __func__);
1254                         dev_kfree_skb(skb);
1255 
1256                         /* Do not accept this connection attempt */
1257                         return;
1258                 }
1259                 /* Remove parameters */
1260                 skb_pull(skb, IRDA_MIN(skb->len, plen+1));
1261         }
1262 
1263         IRDA_DEBUG(4, "%s() send=%d,avail=%d,remote=%d\n", __func__,
1264               self->send_credit, self->avail_credit, self->remote_credit);
1265 
1266         IRDA_DEBUG(2, "%s(), MaxSduSize=%d\n", __func__,
1267                    self->tx_max_sdu_size);
1268 
1269         if (self->notify.connect_confirm) {
1270                 self->notify.connect_confirm(self->notify.instance, self, qos,
1271                                              self->tx_max_sdu_size,
1272                                              self->max_header_size, skb);
1273         } else
1274                 dev_kfree_skb(skb);
1275 }
1276 
1277 /*
1278  * Function irttp_connect_indication (handle, skb)
1279  *
1280  *    Some other device is connecting to this TSAP
1281  *
1282  */
1283 static void irttp_connect_indication(void *instance, void *sap,
1284                 struct qos_info *qos, __u32 max_seg_size, __u8 max_header_size,
1285                 struct sk_buff *skb)
1286 {
1287         struct tsap_cb *self;
1288         struct lsap_cb *lsap;
1289         int parameters;
1290         int ret;
1291         __u8 plen;
1292         __u8 n;
1293 
1294         self = instance;
1295 
1296         IRDA_ASSERT(self != NULL, return;);
1297         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1298         IRDA_ASSERT(skb != NULL, return;);
1299 
1300         lsap = sap;
1301 
1302         self->max_seg_size = max_seg_size - TTP_HEADER;
1303         self->max_header_size = max_header_size+TTP_HEADER;
1304 
1305         IRDA_DEBUG(4, "%s(), TSAP sel=%02x\n", __func__, self->stsap_sel);
1306 
1307         /* Need to update dtsap_sel if its equal to LSAP_ANY */
1308         self->dtsap_sel = lsap->dlsap_sel;
1309 
1310         n = skb->data[0] & 0x7f;
1311 
1312         self->send_credit = n;
1313         self->tx_max_sdu_size = 0;
1314 
1315         parameters = skb->data[0] & 0x80;
1316 
1317         IRDA_ASSERT(skb->len >= TTP_HEADER, return;);
1318         skb_pull(skb, TTP_HEADER);
1319 
1320         if (parameters) {
1321                 plen = skb->data[0];
1322 
1323                 ret = irda_param_extract_all(self, skb->data+1,
1324                                              IRDA_MIN(skb->len-1, plen),
1325                                              &param_info);
1326 
1327                 /* Any errors in the parameter list? */
1328                 if (ret < 0) {
1329                         IRDA_WARNING("%s: error extracting parameters\n",
1330                                      __func__);
1331                         dev_kfree_skb(skb);
1332 
1333                         /* Do not accept this connection attempt */
1334                         return;
1335                 }
1336 
1337                 /* Remove parameters */
1338                 skb_pull(skb, IRDA_MIN(skb->len, plen+1));
1339         }
1340 
1341         if (self->notify.connect_indication) {
1342                 self->notify.connect_indication(self->notify.instance, self,
1343                                                 qos, self->tx_max_sdu_size,
1344                                                 self->max_header_size, skb);
1345         } else
1346                 dev_kfree_skb(skb);
1347 }
1348 
1349 /*
1350  * Function irttp_connect_response (handle, userdata)
1351  *
1352  *    Service user is accepting the connection, just pass it down to
1353  *    IrLMP!
1354  *
1355  */
1356 int irttp_connect_response(struct tsap_cb *self, __u32 max_sdu_size,
1357                            struct sk_buff *userdata)
1358 {
1359         struct sk_buff *tx_skb;
1360         __u8 *frame;
1361         int ret;
1362         __u8 n;
1363 
1364         IRDA_ASSERT(self != NULL, return -1;);
1365         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
1366 
1367         IRDA_DEBUG(4, "%s(), Source TSAP selector=%02x\n", __func__,
1368                    self->stsap_sel);
1369 
1370         /* Any userdata supplied? */
1371         if (userdata == NULL) {
1372                 tx_skb = alloc_skb(TTP_MAX_HEADER + TTP_SAR_HEADER,
1373                                    GFP_ATOMIC);
1374                 if (!tx_skb)
1375                         return -ENOMEM;
1376 
1377                 /* Reserve space for MUX_CONTROL and LAP header */
1378                 skb_reserve(tx_skb, TTP_MAX_HEADER + TTP_SAR_HEADER);
1379         } else {
1380                 tx_skb = userdata;
1381                 /*
1382                  *  Check that the client has reserved enough space for
1383                  *  headers
1384                  */
1385                 IRDA_ASSERT(skb_headroom(userdata) >= TTP_MAX_HEADER,
1386                         { dev_kfree_skb(userdata); return -1; });
1387         }
1388 
1389         self->avail_credit = 0;
1390         self->remote_credit = 0;
1391         self->rx_max_sdu_size = max_sdu_size;
1392         self->rx_sdu_size = 0;
1393         self->rx_sdu_busy = FALSE;
1394 
1395         n = self->initial_credit;
1396 
1397         /* Frame has only space for max 127 credits (7 bits) */
1398         if (n > 127) {
1399                 self->avail_credit = n - 127;
1400                 n = 127;
1401         }
1402 
1403         self->remote_credit = n;
1404         self->connected = TRUE;
1405 
1406         /* SAR enabled? */
1407         if (max_sdu_size > 0) {
1408                 IRDA_ASSERT(skb_headroom(tx_skb) >= (TTP_MAX_HEADER + TTP_SAR_HEADER),
1409                         { dev_kfree_skb(tx_skb); return -1; });
1410 
1411                 /* Insert TTP header with SAR parameters */
1412                 frame = skb_push(tx_skb, TTP_HEADER + TTP_SAR_HEADER);
1413 
1414                 frame[0] = TTP_PARAMETERS | n;
1415                 frame[1] = 0x04; /* Length */
1416 
1417                 /* irda_param_insert(self, IRTTP_MAX_SDU_SIZE, frame+1,  */
1418 /*                                TTP_SAR_HEADER, &param_info) */
1419 
1420                 frame[2] = 0x01; /* MaxSduSize */
1421                 frame[3] = 0x02; /* Value length */
1422 
1423                 put_unaligned(cpu_to_be16((__u16) max_sdu_size),
1424                               (__be16 *)(frame+4));
1425         } else {
1426                 /* Insert TTP header */
1427                 frame = skb_push(tx_skb, TTP_HEADER);
1428 
1429                 frame[0] = n & 0x7f;
1430         }
1431 
1432         ret = irlmp_connect_response(self->lsap, tx_skb);
1433 
1434         return ret;
1435 }
1436 EXPORT_SYMBOL(irttp_connect_response);
1437 
1438 /*
1439  * Function irttp_dup (self, instance)
1440  *
1441  *    Duplicate TSAP, can be used by servers to confirm a connection on a
1442  *    new TSAP so it can keep listening on the old one.
1443  */
1444 struct tsap_cb *irttp_dup(struct tsap_cb *orig, void *instance)
1445 {
1446         struct tsap_cb *new;
1447         unsigned long flags;
1448 
1449         IRDA_DEBUG(1, "%s()\n", __func__);
1450 
1451         /* Protect our access to the old tsap instance */
1452         spin_lock_irqsave(&irttp->tsaps->hb_spinlock, flags);
1453 
1454         /* Find the old instance */
1455         if (!hashbin_find(irttp->tsaps, (long) orig, NULL)) {
1456                 IRDA_DEBUG(0, "%s(), unable to find TSAP\n", __func__);
1457                 spin_unlock_irqrestore(&irttp->tsaps->hb_spinlock, flags);
1458                 return NULL;
1459         }
1460 
1461         /* Allocate a new instance */
1462         new = kmemdup(orig, sizeof(struct tsap_cb), GFP_ATOMIC);
1463         if (!new) {
1464                 IRDA_DEBUG(0, "%s(), unable to kmalloc\n", __func__);
1465                 spin_unlock_irqrestore(&irttp->tsaps->hb_spinlock, flags);
1466                 return NULL;
1467         }
1468         spin_lock_init(&new->lock);
1469 
1470         /* We don't need the old instance any more */
1471         spin_unlock_irqrestore(&irttp->tsaps->hb_spinlock, flags);
1472 
1473         /* Try to dup the LSAP (may fail if we were too slow) */
1474         new->lsap = irlmp_dup(orig->lsap, new);
1475         if (!new->lsap) {
1476                 IRDA_DEBUG(0, "%s(), dup failed!\n", __func__);
1477                 kfree(new);
1478                 return NULL;
1479         }
1480 
1481         /* Not everything should be copied */
1482         new->notify.instance = instance;
1483 
1484         /* Initialize internal objects */
1485         irttp_init_tsap(new);
1486 
1487         /* This is locked */
1488         hashbin_insert(irttp->tsaps, (irda_queue_t *) new, (long) new, NULL);
1489 
1490         return new;
1491 }
1492 EXPORT_SYMBOL(irttp_dup);
1493 
1494 /*
1495  * Function irttp_disconnect_request (self)
1496  *
1497  *    Close this connection please! If priority is high, the queued data
1498  *    segments, if any, will be deallocated first
1499  *
1500  */
1501 int irttp_disconnect_request(struct tsap_cb *self, struct sk_buff *userdata,
1502                              int priority)
1503 {
1504         int ret;
1505 
1506         IRDA_ASSERT(self != NULL, return -1;);
1507         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
1508 
1509         /* Already disconnected? */
1510         if (!self->connected) {
1511                 IRDA_DEBUG(4, "%s(), already disconnected!\n", __func__);
1512                 if (userdata)
1513                         dev_kfree_skb(userdata);
1514                 return -1;
1515         }
1516 
1517         /* Disconnect already pending ?
1518          * We need to use an atomic operation to prevent reentry. This
1519          * function may be called from various context, like user, timer
1520          * for following a disconnect_indication() (i.e. net_bh).
1521          * Jean II */
1522         if (test_and_set_bit(0, &self->disconnect_pend)) {
1523                 IRDA_DEBUG(0, "%s(), disconnect already pending\n",
1524                            __func__);
1525                 if (userdata)
1526                         dev_kfree_skb(userdata);
1527 
1528                 /* Try to make some progress */
1529                 irttp_run_tx_queue(self);
1530                 return -1;
1531         }
1532 
1533         /*
1534          *  Check if there is still data segments in the transmit queue
1535          */
1536         if (!skb_queue_empty(&self->tx_queue)) {
1537                 if (priority == P_HIGH) {
1538                         /*
1539                          *  No need to send the queued data, if we are
1540                          *  disconnecting right now since the data will
1541                          *  not have any usable connection to be sent on
1542                          */
1543                         IRDA_DEBUG(1, "%s(): High priority!!()\n", __func__);
1544                         irttp_flush_queues(self);
1545                 } else if (priority == P_NORMAL) {
1546                         /*
1547                          *  Must delay disconnect until after all data segments
1548                          *  have been sent and the tx_queue is empty
1549                          */
1550                         /* We'll reuse this one later for the disconnect */
1551                         self->disconnect_skb = userdata;  /* May be NULL */
1552 
1553                         irttp_run_tx_queue(self);
1554 
1555                         irttp_start_todo_timer(self, HZ/10);
1556                         return -1;
1557                 }
1558         }
1559         /* Note : we don't need to check if self->rx_queue is full and the
1560          * state of self->rx_sdu_busy because the disconnect response will
1561          * be sent at the LMP level (so even if the peer has its Tx queue
1562          * full of data). - Jean II */
1563 
1564         IRDA_DEBUG(1, "%s(), Disconnecting ...\n", __func__);
1565         self->connected = FALSE;
1566 
1567         if (!userdata) {
1568                 struct sk_buff *tx_skb;
1569                 tx_skb = alloc_skb(LMP_MAX_HEADER, GFP_ATOMIC);
1570                 if (!tx_skb)
1571                         return -ENOMEM;
1572 
1573                 /*
1574                  *  Reserve space for MUX and LAP header
1575                  */
1576                 skb_reserve(tx_skb, LMP_MAX_HEADER);
1577 
1578                 userdata = tx_skb;
1579         }
1580         ret = irlmp_disconnect_request(self->lsap, userdata);
1581 
1582         /* The disconnect is no longer pending */
1583         clear_bit(0, &self->disconnect_pend);   /* FALSE */
1584 
1585         return ret;
1586 }
1587 EXPORT_SYMBOL(irttp_disconnect_request);
1588 
1589 /*
1590  * Function irttp_disconnect_indication (self, reason)
1591  *
1592  *    Disconnect indication, TSAP disconnected by peer?
1593  *
1594  */
1595 static void irttp_disconnect_indication(void *instance, void *sap,
1596                 LM_REASON reason, struct sk_buff *skb)
1597 {
1598         struct tsap_cb *self;
1599 
1600         IRDA_DEBUG(4, "%s()\n", __func__);
1601 
1602         self = instance;
1603 
1604         IRDA_ASSERT(self != NULL, return;);
1605         IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
1606 
1607         /* Prevent higher layer to send more data */
1608         self->connected = FALSE;
1609 
1610         /* Check if client has already tried to close the TSAP */
1611         if (self->close_pend) {
1612                 /* In this case, the higher layer is probably gone. Don't
1613                  * bother it and clean up the remains - Jean II */
1614                 if (skb)
1615                         dev_kfree_skb(skb);
1616                 irttp_close_tsap(self);
1617                 return;
1618         }
1619 
1620         /* If we are here, we assume that is the higher layer is still
1621          * waiting for the disconnect notification and able to process it,
1622          * even if he tried to disconnect. Otherwise, it would have already
1623          * attempted to close the tsap and self->close_pend would be TRUE.
1624          * Jean II */
1625 
1626         /* No need to notify the client if has already tried to disconnect */
1627         if (self->notify.disconnect_indication)
1628                 self->notify.disconnect_indication(self->notify.instance, self,
1629                                                    reason, skb);
1630         else
1631                 if (skb)
1632                         dev_kfree_skb(skb);
1633 }
1634 
1635 /*
1636  * Function irttp_do_data_indication (self, skb)
1637  *
1638  *    Try to deliver reassembled skb to layer above, and requeue it if that
1639  *    for some reason should fail. We mark rx sdu as busy to apply back
1640  *    pressure is necessary.
1641  */
1642 static void irttp_do_data_indication(struct tsap_cb *self, struct sk_buff *skb)
1643 {
1644         int err;
1645 
1646         /* Check if client has already closed the TSAP and gone away */
1647         if (self->close_pend) {
1648                 dev_kfree_skb(skb);
1649                 return;
1650         }
1651 
1652         err = self->notify.data_indication(self->notify.instance, self, skb);
1653 
1654         /* Usually the layer above will notify that it's input queue is
1655          * starting to get filled by using the flow request, but this may
1656          * be difficult, so it can instead just refuse to eat it and just
1657          * give an error back
1658          */
1659         if (err) {
1660                 IRDA_DEBUG(0, "%s() requeueing skb!\n", __func__);
1661 
1662                 /* Make sure we take a break */
1663                 self->rx_sdu_busy = TRUE;
1664 
1665                 /* Need to push the header in again */
1666                 skb_push(skb, TTP_HEADER);
1667                 skb->data[0] = 0x00; /* Make sure MORE bit is cleared */
1668 
1669                 /* Put skb back on queue */
1670                 skb_queue_head(&self->rx_queue, skb);
1671         }
1672 }
1673 
1674 /*
1675  * Function irttp_run_rx_queue (self)
1676  *
1677  *     Check if we have any frames to be transmitted, or if we have any
1678  *     available credit to give away.
1679  */
1680 static void irttp_run_rx_queue(struct tsap_cb *self)
1681 {
1682         struct sk_buff *skb;
1683         int more = 0;
1684 
1685         IRDA_DEBUG(2, "%s() send=%d,avail=%d,remote=%d\n", __func__,
1686                    self->send_credit, self->avail_credit, self->remote_credit);
1687 
1688         /* Get exclusive access to the rx queue, otherwise don't touch it */
1689         if (irda_lock(&self->rx_queue_lock) == FALSE)
1690                 return;
1691 
1692         /*
1693          *  Reassemble all frames in receive queue and deliver them
1694          */
1695         while (!self->rx_sdu_busy && (skb = skb_dequeue(&self->rx_queue))) {
1696                 /* This bit will tell us if it's the last fragment or not */
1697                 more = skb->data[0] & 0x80;
1698 
1699                 /* Remove TTP header */
1700                 skb_pull(skb, TTP_HEADER);
1701 
1702                 /* Add the length of the remaining data */
1703                 self->rx_sdu_size += skb->len;
1704 
1705                 /*
1706                  * If SAR is disabled, or user has requested no reassembly
1707                  * of received fragments then we just deliver them
1708                  * immediately. This can be requested by clients that
1709                  * implements byte streams without any message boundaries
1710                  */
1711                 if (self->rx_max_sdu_size == TTP_SAR_DISABLE) {
1712                         irttp_do_data_indication(self, skb);
1713                         self->rx_sdu_size = 0;
1714 
1715                         continue;
1716                 }
1717 
1718                 /* Check if this is a fragment, and not the last fragment */
1719                 if (more) {
1720                         /*
1721                          *  Queue the fragment if we still are within the
1722                          *  limits of the maximum size of the rx_sdu
1723                          */
1724                         if (self->rx_sdu_size <= self->rx_max_sdu_size) {
1725                                 IRDA_DEBUG(4, "%s(), queueing frag\n",
1726                                            __func__);
1727                                 skb_queue_tail(&self->rx_fragments, skb);
1728                         } else {
1729                                 /* Free the part of the SDU that is too big */
1730                                 dev_kfree_skb(skb);
1731                         }
1732                         continue;
1733                 }
1734                 /*
1735                  *  This is the last fragment, so time to reassemble!
1736                  */
1737                 if ((self->rx_sdu_size <= self->rx_max_sdu_size) ||
1738                     (self->rx_max_sdu_size == TTP_SAR_UNBOUND)) {
1739                         /*
1740                          * A little optimizing. Only queue the fragment if
1741                          * there are other fragments. Since if this is the
1742                          * last and only fragment, there is no need to
1743                          * reassemble :-)
1744                          */
1745                         if (!skb_queue_empty(&self->rx_fragments)) {
1746                                 skb_queue_tail(&self->rx_fragments,
1747                                                skb);
1748 
1749                                 skb = irttp_reassemble_skb(self);
1750                         }
1751 
1752                         /* Now we can deliver the reassembled skb */
1753                         irttp_do_data_indication(self, skb);
1754                 } else {
1755                         IRDA_DEBUG(1, "%s(), Truncated frame\n", __func__);
1756 
1757                         /* Free the part of the SDU that is too big */
1758                         dev_kfree_skb(skb);
1759 
1760                         /* Deliver only the valid but truncated part of SDU */
1761                         skb = irttp_reassemble_skb(self);
1762 
1763                         irttp_do_data_indication(self, skb);
1764                 }
1765                 self->rx_sdu_size = 0;
1766         }
1767 
1768         /*
1769          * It's not trivial to keep track of how many credits are available
1770          * by incrementing at each packet, because delivery may fail
1771          * (irttp_do_data_indication() may requeue the frame) and because
1772          * we need to take care of fragmentation.
1773          * We want the other side to send up to initial_credit packets.
1774          * We have some frames in our queues, and we have already allowed it
1775          * to send remote_credit.
1776          * No need to spinlock, write is atomic and self correcting...
1777          * Jean II
1778          */
1779         self->avail_credit = (self->initial_credit -
1780                               (self->remote_credit +
1781                                skb_queue_len(&self->rx_queue) +
1782                                skb_queue_len(&self->rx_fragments)));
1783 
1784         /* Do we have too much credits to send to peer ? */
1785         if ((self->remote_credit <= TTP_RX_MIN_CREDIT) &&
1786             (self->avail_credit > 0)) {
1787                 /* Send explicit credit frame */
1788                 irttp_give_credit(self);
1789                 /* Note : do *NOT* check if tx_queue is non-empty, that
1790                  * will produce deadlocks. I repeat : send a credit frame
1791                  * even if we have something to send in our Tx queue.
1792                  * If we have credits, it means that our Tx queue is blocked.
1793                  *
1794                  * Let's suppose the peer can't keep up with our Tx. He will
1795                  * flow control us by not sending us any credits, and we
1796                  * will stop Tx and start accumulating credits here.
1797                  * Up to the point where the peer will stop its Tx queue,
1798                  * for lack of credits.
1799                  * Let's assume the peer application is single threaded.
1800                  * It will block on Tx and never consume any Rx buffer.
1801                  * Deadlock. Guaranteed. - Jean II
1802                  */
1803         }
1804 
1805         /* Reset lock */
1806         self->rx_queue_lock = 0;
1807 }
1808 
1809 #ifdef CONFIG_PROC_FS
1810 struct irttp_iter_state {
1811         int id;
1812 };
1813 
1814 static void *irttp_seq_start(struct seq_file *seq, loff_t *pos)
1815 {
1816         struct irttp_iter_state *iter = seq->private;
1817         struct tsap_cb *self;
1818 
1819         /* Protect our access to the tsap list */
1820         spin_lock_irq(&irttp->tsaps->hb_spinlock);
1821         iter->id = 0;
1822 
1823         for (self = (struct tsap_cb *) hashbin_get_first(irttp->tsaps);
1824              self != NULL;
1825              self = (struct tsap_cb *) hashbin_get_next(irttp->tsaps)) {
1826                 if (iter->id == *pos)
1827                         break;
1828                 ++iter->id;
1829         }
1830 
1831         return self;
1832 }
1833 
1834 static void *irttp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1835 {
1836         struct irttp_iter_state *iter = seq->private;
1837 
1838         ++*pos;
1839         ++iter->id;
1840         return (void *) hashbin_get_next(irttp->tsaps);
1841 }
1842 
1843 static void irttp_seq_stop(struct seq_file *seq, void *v)
1844 {
1845         spin_unlock_irq(&irttp->tsaps->hb_spinlock);
1846 }
1847 
1848 static int irttp_seq_show(struct seq_file *seq, void *v)
1849 {
1850         const struct irttp_iter_state *iter = seq->private;
1851         const struct tsap_cb *self = v;
1852 
1853         seq_printf(seq, "TSAP %d, ", iter->id);
1854         seq_printf(seq, "stsap_sel: %02x, ",
1855                    self->stsap_sel);
1856         seq_printf(seq, "dtsap_sel: %02x\n",
1857                    self->dtsap_sel);
1858         seq_printf(seq, "  connected: %s, ",
1859                    self->connected ? "TRUE" : "FALSE");
1860         seq_printf(seq, "avail credit: %d, ",
1861                    self->avail_credit);
1862         seq_printf(seq, "remote credit: %d, ",
1863                    self->remote_credit);
1864         seq_printf(seq, "send credit: %d\n",
1865                    self->send_credit);
1866         seq_printf(seq, "  tx packets: %lu, ",
1867                    self->stats.tx_packets);
1868         seq_printf(seq, "rx packets: %lu, ",
1869                    self->stats.rx_packets);
1870         seq_printf(seq, "tx_queue len: %u ",
1871                    skb_queue_len(&self->tx_queue));
1872         seq_printf(seq, "rx_queue len: %u\n",
1873                    skb_queue_len(&self->rx_queue));
1874         seq_printf(seq, "  tx_sdu_busy: %s, ",
1875                    self->tx_sdu_busy ? "TRUE" : "FALSE");
1876         seq_printf(seq, "rx_sdu_busy: %s\n",
1877                    self->rx_sdu_busy ? "TRUE" : "FALSE");
1878         seq_printf(seq, "  max_seg_size: %u, ",
1879                    self->max_seg_size);
1880         seq_printf(seq, "tx_max_sdu_size: %u, ",
1881                    self->tx_max_sdu_size);
1882         seq_printf(seq, "rx_max_sdu_size: %u\n",
1883                    self->rx_max_sdu_size);
1884 
1885         seq_printf(seq, "  Used by (%s)\n\n",
1886                    self->notify.name);
1887         return 0;
1888 }
1889 
1890 static const struct seq_operations irttp_seq_ops = {
1891         .start  = irttp_seq_start,
1892         .next   = irttp_seq_next,
1893         .stop   = irttp_seq_stop,
1894         .show   = irttp_seq_show,
1895 };
1896 
1897 static int irttp_seq_open(struct inode *inode, struct file *file)
1898 {
1899         return seq_open_private(file, &irttp_seq_ops,
1900                         sizeof(struct irttp_iter_state));
1901 }
1902 
1903 const struct file_operations irttp_seq_fops = {
1904         .owner          = THIS_MODULE,
1905         .open           = irttp_seq_open,
1906         .read           = seq_read,
1907         .llseek         = seq_lseek,
1908         .release        = seq_release_private,
1909 };
1910 
1911 #endif /* PROC_FS */
1912 

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