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

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