-
Notifications
You must be signed in to change notification settings - Fork 314
/
Copy pathxmit.c
1506 lines (1207 loc) · 40.2 KB
/
xmit.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
//
// This file is part of Dire Wolf, an amateur radio packet TNC.
//
// Copyright (C) 2011, 2013, 2014, 2015, 2016, 2017 John Langner, WB2OSZ
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
/*------------------------------------------------------------------
*
* Module: xmit.c
*
* Purpose: Transmit queued up packets when channel is clear.
*
* Description: Producers of packets to be transmitted call tq_append and then
* go merrily on their way, unconcerned about when the packet might
* actually get transmitted.
*
* This thread waits until the channel is clear and then removes
* packets from the queue and transmits them.
*
*
* Usage: (1) The main application calls xmit_init.
*
* This will initialize the transmit packet queue
* and create a thread to empty the queue when
* the channel is clear.
*
* (2) The application queues up packets by calling tq_append.
*
* Packets that are being digipeated should go in the
* high priority queue so they will go out first.
*
* Other packets should go into the lower priority queue.
*
* (3) xmit_thread removes packets from the queue and transmits
* them when other signals are not being heard.
*
*---------------------------------------------------------------*/
#include "direwolf.h"
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <math.h>
#include <errno.h>
#include <stddef.h>
#include "direwolf.h"
#include "ax25_pad.h"
#include "textcolor.h"
#include "audio.h"
#include "tq.h"
#include "xmit.h"
#include "hdlc_send.h"
#include "hdlc_rec.h"
#include "ptt.h"
#include "dtime_now.h"
#include "morse.h"
#include "dtmf.h"
#include "xid.h"
#include "dlq.h"
#include "server.h"
/*
* Parameters for transmission.
* Each channel can have different timing values.
*
* These are initialized once at application startup time
* and some can be changed later by commands from connected applications.
*/
static int xmit_slottime[MAX_CHANS]; /* Slot time in 10 mS units for persistence algorithm. */
static int xmit_persist[MAX_CHANS]; /* Sets probability for transmitting after each */
/* slot time delay. Transmit if a random number */
/* in range of 0 - 255 <= persist value. */
/* Otherwise wait another slot time and try again. */
static int xmit_txdelay[MAX_CHANS]; /* After turning on the transmitter, */
/* send "flags" for txdelay * 10 mS. */
static int xmit_txtail[MAX_CHANS]; /* Amount of time to keep transmitting after we */
/* are done sending the data. This is to avoid */
/* dropping PTT too soon and chopping off the end */
/* of the frame. Again 10 mS units. */
static int xmit_fulldup[MAX_CHANS]; /* Full duplex if non-zero. */
static int xmit_bits_per_sec[MAX_CHANS]; /* Data transmission rate. */
/* Often called baud rate which is equivalent for */
/* 1200 & 9600 cases but could be different with other */
/* modulation techniques. */
static int g_debug_xmit_packet; /* print packet in hexadecimal form for debugging. */
// TODO: When this was first written, bits/sec was same as baud.
// Need to revisit this for PSK modes where they are not the same.
#if 0 // Added during 1.5 beta test
static int BITS_TO_MS (int b, int ch) {
int bits_per_symbol;
switch (save_audio_config_p->achan[ch].modem_type) {
case MODEM_QPSK: bits_per_symbol = 2; break;
case MODEM_8PSK: bits_per_symbol = 3; break;
case default: bits_per_symbol = 1; break;
}
return ( (b * 1000) / (xmit_bits_per_sec[(ch)] * bits_per_symbol) );
}
static int MS_TO_BITS (int ms, int ch) {
int bits_per_symbol;
switch (save_audio_config_p->achan[ch].modem_type) {
case MODEM_QPSK: bits_per_symbol = 2; break;
case MODEM_8PSK: bits_per_symbol = 3; break;
case default: bits_per_symbol = 1; break;
}
return ( (ms * xmit_bits_per_sec[(ch)] * bits_per_symbol) / 1000 ); TODO...
}
#else // OK for 1200, 9600 but wrong for PSK
#define BITS_TO_MS(b,ch) (((b)*1000)/xmit_bits_per_sec[(ch)])
#define MS_TO_BITS(ms,ch) (((ms)*xmit_bits_per_sec[(ch)])/1000)
#endif
#define MAXX(a,b) (((a)>(b)) ? (a) : (b))
#if __WIN32__
static unsigned __stdcall xmit_thread (void *arg);
#else
static void * xmit_thread (void *arg);
#endif
/*
* When an audio device is in stereo mode, we can have two
* different channels that want to transmit at the same time.
* We are not clever enough to multiplex them so use this
* so only one is activte at the same time.
*/
static dw_mutex_t audio_out_dev_mutex[MAX_ADEVS];
static int wait_for_clear_channel (int channel, int slotttime, int persist, int fulldup);
static void xmit_ax25_frames (int c, int p, packet_t pp, int max_bundle);
static int send_one_frame (int c, int p, packet_t pp);
static void xmit_speech (int c, packet_t pp);
static void xmit_morse (int c, packet_t pp, int wpm);
static void xmit_dtmf (int c, packet_t pp, int speed);
/*-------------------------------------------------------------------
*
* Name: xmit_init
*
* Purpose: Initialize the transmit process.
*
* Inputs: modem - Structure with modem and timing parameters.
*
*
* Outputs: Remember required information for future use.
*
* Description: Initialize the queue to be empty and set up other
* mechanisms for sharing it between different threads.
*
* Start up xmit_thread(s) to actually send the packets
* at the appropriate time.
*
* Version 1.2: We now allow multiple audio devices with one or two channels each.
* Each audio channel has its own thread.
*
*--------------------------------------------------------------------*/
static struct audio_s *save_audio_config_p;
void xmit_init (struct audio_s *p_modem, int debug_xmit_packet)
{
int j;
int ad;
#if __WIN32__
HANDLE xmit_th[MAX_CHANS];
#else
//pthread_attr_t attr;
//struct sched_param sp;
pthread_t xmit_tid[MAX_CHANS];
#endif
//int e;
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_init ( ... )\n");
#endif
save_audio_config_p = p_modem;
g_debug_xmit_packet = debug_xmit_packet;
/*
* Push to Talk (PTT) control.
*/
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_init: about to call ptt_init \n");
#endif
ptt_init (p_modem);
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_init: back from ptt_init \n");
#endif
/*
* Save parameters for later use.
* TODO1.2: Any reason to use global config rather than making a copy?
*/
for (j=0; j<MAX_CHANS; j++) {
xmit_bits_per_sec[j] = p_modem->achan[j].baud;
xmit_slottime[j] = p_modem->achan[j].slottime;
xmit_persist[j] = p_modem->achan[j].persist;
xmit_txdelay[j] = p_modem->achan[j].txdelay;
xmit_txtail[j] = p_modem->achan[j].txtail;
xmit_fulldup[j] = p_modem->achan[j].fulldup;
}
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_init: about to call tq_init \n");
#endif
tq_init (p_modem);
for (ad = 0; ad < MAX_ADEVS; ad++) {
dw_mutex_init (&(audio_out_dev_mutex[ad]));
}
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_init: about to create threads \n");
#endif
//TODO: xmit thread should be higher priority to avoid
// underrun on the audio output device.
for (j=0; j<MAX_CHANS; j++) {
if (p_modem->chan_medium[j] == MEDIUM_RADIO) {
#if __WIN32__
xmit_th[j] = (HANDLE)_beginthreadex (NULL, 0, xmit_thread, (void*)(ptrdiff_t)j, 0, NULL);
if (xmit_th[j] == NULL) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Could not create xmit thread %d\n", j);
return;
}
#else
int e;
#if 0
//TODO: not this simple. probably need FIFO policy.
pthread_attr_init (&attr);
e = pthread_attr_getschedparam (&attr, &sp);
if (e != 0) {
text_color_set(DW_COLOR_ERROR);
perror("pthread_attr_getschedparam");
}
text_color_set(DW_COLOR_ERROR);
dw_printf ("Default scheduling priority = %d, min=%d, max=%d\n",
sp.sched_priority,
sched_get_priority_min(SCHED_OTHER),
sched_get_priority_max(SCHED_OTHER));
sp.sched_priority--;
e = pthread_attr_setschedparam (&attr, &sp);
if (e != 0) {
text_color_set(DW_COLOR_ERROR);
perror("pthread_attr_setschedparam");
}
e = pthread_create (&(xmit_tid[j]), &attr, xmit_thread, (void *)(ptrdiff_t)j);
pthread_attr_destroy (&attr);
#else
e = pthread_create (&(xmit_tid[j]), NULL, xmit_thread, (void *)(ptrdiff_t)j);
#endif
if (e != 0) {
text_color_set(DW_COLOR_ERROR);
perror("Could not create xmit thread for audio device");
return;
}
#endif
}
}
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_init: finished \n");
#endif
} /* end tq_init */
/*-------------------------------------------------------------------
*
* Name: xmit_set_txdelay
* xmit_set_persist
* xmit_set_slottime
* xmit_set_txtail
* xmit_set_fulldup
*
*
* Purpose: The KISS protocol, and maybe others, can specify
* transmit timing parameters. If the application
* specifies these, they will override what was read
* from the configuration file.
*
* Inputs: channel - should be 0 or 1.
*
* value - time values are in 10 mSec units.
*
*
* Outputs: Remember required information for future use.
*
* Question: Should we have an option to enable or disable the
* application changing these values?
*
* Bugs: No validity checking other than array subscript out of bounds.
*
*--------------------------------------------------------------------*/
void xmit_set_txdelay (int channel, int value)
{
if (channel >= 0 && channel < MAX_CHANS) {
xmit_txdelay[channel] = value;
}
}
void xmit_set_persist (int channel, int value)
{
if (channel >= 0 && channel < MAX_CHANS) {
xmit_persist[channel] = value;
}
}
void xmit_set_slottime (int channel, int value)
{
if (channel >= 0 && channel < MAX_CHANS) {
xmit_slottime[channel] = value;
}
}
void xmit_set_txtail (int channel, int value)
{
if (channel >= 0 && channel < MAX_CHANS) {
xmit_txtail[channel] = value;
}
}
void xmit_set_fulldup (int channel, int value)
{
if (channel >= 0 && channel < MAX_CHANS) {
xmit_fulldup[channel] = value;
}
}
/*-------------------------------------------------------------------
*
* Name: frame_flavor
*
* Purpose: Separate frames into different flavors so we can decide
* which can be bundled into a single transmission and which should
* be sent separately.
*
* Inputs: pp - Packet object.
*
* Returns: Flavor, one of:
*
* FLAVOR_SPEECH - Destination address is SPEECH.
* FLAVOR_MORSE - Destination address is MORSE.
* FLAVOR_DTMF - Destination address is DTMF.
* FLAVOR_APRS_NEW - APRS original, i.e. not digipeating.
* FLAVOR_APRS_DIGI - APRS digipeating.
* FLAVOR_OTHER - Anything left over, i.e. connected mode.
*
*--------------------------------------------------------------------*/
typedef enum flavor_e { FLAVOR_APRS_NEW, FLAVOR_APRS_DIGI, FLAVOR_SPEECH, FLAVOR_MORSE, FLAVOR_DTMF, FLAVOR_OTHER } flavor_t;
static flavor_t frame_flavor (packet_t pp)
{
if (ax25_is_aprs (pp)) { // UI frame, PID 0xF0.
// It's unfortunate APRS did not use its own special PID.
char dest[AX25_MAX_ADDR_LEN];
ax25_get_addr_no_ssid(pp, AX25_DESTINATION, dest);
if (strcmp(dest, "SPEECH") == 0) {
return (FLAVOR_SPEECH);
}
if (strcmp(dest, "MORSE") == 0) {
return (FLAVOR_MORSE);
}
if (strcmp(dest, "DTMF") == 0) {
return (FLAVOR_DTMF);
}
/* Is there at least one digipeater AND has first one been used? */
/* I could be the first in the list or later. Doesn't matter. */
if (ax25_get_num_repeaters(pp) >= 1 && ax25_get_h(pp,AX25_REPEATER_1)) {
return (FLAVOR_APRS_DIGI);
}
return (FLAVOR_APRS_NEW);
}
return (FLAVOR_OTHER);
} /* end frame_flavor */
/*-------------------------------------------------------------------
*
* Name: xmit_thread
*
* Purpose: Process transmit queue for one channel.
*
* Inputs: transmit packet queue.
*
* Outputs:
*
* Description: We have different timing rules for different types of
* packets so they are put into different queues.
*
* High Priority -
*
* Packets which are being digipeated go out first.
* Latest recommendations are to retransmit these
* immdediately (after no one else is heard, of course)
* rather than waiting random times to avoid collisions.
* The KPC-3 configuration option for this is "UIDWAIT OFF". (?)
*
* AX.25 connected mode also has a couple cases
* where "expedited" frames are sent.
*
* Low Priority -
*
* Other packets are sent after a random wait time
* (determined by PERSIST & SLOTTIME) to help avoid
* collisions.
*
* If more than one audio channel is being used, a separate
* pair of transmit queues is used for each channel.
*
*
*
* Version 1.2: Allow more than one audio device.
* each channel has its own thread.
* Add speech capability.
*
* Version 1.4: Rearranged logic for bundling multiple frames into a single transmission.
*
* The rule is that Speech, Morse Code, DTMF, and APRS digipeated frames
* are all sent separately. The rest can be bundled.
*
*--------------------------------------------------------------------*/
#if __WIN32__
static unsigned __stdcall xmit_thread (void *arg)
#else
static void * xmit_thread (void *arg)
#endif
{
int chan = (int)(ptrdiff_t)arg; // channel number.
packet_t pp;
int prio;
int ok;
while (1) {
tq_wait_while_empty (chan);
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_thread, channel %d: woke up\n", chan);
#endif
// Does this extra loop offer any benefit?
while (tq_peek(chan, TQ_PRIO_0_HI) != NULL || tq_peek(chan, TQ_PRIO_1_LO) != NULL) {
/*
* Wait for the channel to be clear.
* If there is something in the high priority queue, begin transmitting immediately.
* Otherwise, wait a random amount of time, in hopes of minimizing collisions.
*/
ok = wait_for_clear_channel (chan, xmit_slottime[chan], xmit_persist[chan], xmit_fulldup[chan]);
prio = TQ_PRIO_1_LO;
pp = tq_remove (chan, TQ_PRIO_0_HI);
if (pp != NULL) {
prio = TQ_PRIO_0_HI;
}
else {
pp = tq_remove (chan, TQ_PRIO_1_LO);
}
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_thread: tq_remove(chan=%d, prio=%d) returned %p\n", chan, prio, pp);
#endif
// Shouldn't have NULL here but be careful.
if (pp != NULL) {
if (ok) {
/*
* Channel is clear and we have lock on output device.
*
* If destination is "SPEECH" send info part to speech synthesizer.
* If destination is "MORSE" send as morse code.
* If destination is "DTMF" send as Touch Tones.
*/
int ssid, wpm, speed;
switch (frame_flavor(pp)) {
case FLAVOR_SPEECH:
xmit_speech (chan, pp);
break;
case FLAVOR_MORSE:
ssid = ax25_get_ssid(pp, AX25_DESTINATION);
wpm = (ssid > 0) ? (ssid * 2) : MORSE_DEFAULT_WPM;
// This is a bit of a hack so we don't respond too quickly for APRStt.
// It will be sent in high priority queue while a beacon wouldn't.
// Add a little delay so user has time release PTT after sending #.
// This and default txdelay would give us a second.
if (prio == TQ_PRIO_0_HI) {
//text_color_set(DW_COLOR_DEBUG);
//dw_printf ("APRStt morse xmit delay hack...\n");
SLEEP_MS (700);
}
xmit_morse (chan, pp, wpm);
break;
case FLAVOR_DTMF:
speed = ax25_get_ssid(pp, AX25_DESTINATION);
if (speed == 0) speed = 5; // default half of maximum
if (speed > 10) speed = 10;
xmit_dtmf (chan, pp, speed);
break;
case FLAVOR_APRS_DIGI:
xmit_ax25_frames (chan, prio, pp, 1); /* 1 means don't bundle */
// I don't know if this in some official specification
// somewhere, but it is generally agreed that APRS digipeaters
// should send only one frame at a time rather than
// bundling multiple frames into a single transmission.
// Discussion here: http://lists.tapr.org/pipermail/aprssig_lists.tapr.org/2021-September/049034.html
break;
case FLAVOR_APRS_NEW:
case FLAVOR_OTHER:
default:
xmit_ax25_frames (chan, prio, pp, 256);
break;
}
// Corresponding lock is in wait_for_clear_channel.
dw_mutex_unlock (&(audio_out_dev_mutex[ACHAN2ADEV(chan)]));
}
else {
/*
* Timeout waiting for clear channel.
* Discard the packet.
* Display with ERROR color rather than XMIT color.
*/
char stemp[1024]; /* max size needed? */
int info_len;
unsigned char *pinfo;
text_color_set(DW_COLOR_ERROR);
dw_printf ("Waited too long for clear channel. Discarding packet below.\n");
ax25_format_addrs (pp, stemp);
info_len = ax25_get_info (pp, &pinfo);
text_color_set(DW_COLOR_INFO);
dw_printf ("[%d%c] ", chan, (prio==TQ_PRIO_0_HI) ? 'H' : 'L');
dw_printf ("%s", stemp); /* stations followed by : */
ax25_safe_print ((char *)pinfo, info_len, ! ax25_is_aprs(pp));
dw_printf ("\n");
ax25_delete (pp);
} /* wait for clear channel error. */
} /* Have pp */
} /* while queue not empty */
} /* while 1 */
return 0; /* unreachable but quiet the warning. */
} /* end xmit_thread */
/*-------------------------------------------------------------------
*
* Name: xmit_ax25_frames
*
* Purpose: After we have a clear channel, and possibly waited a random time,
* we transmit one or more frames.
*
* Inputs: chan - Channel number.
*
* prio - Priority of the first frame.
* Subsequent frames could be different.
*
* pp - Packet object pointer.
* It will be deleted so caller should not try
* to reference it after this.
*
* max_bundle - Max number of frames to bundle into one transmission.
*
* Description: Turn on transmitter.
* Send flags for TXDELAY time.
* Send the first packet, given by pp.
* Possibly send more packets from either queue.
* Send flags for TXTAIL time.
* Turn off transmitter.
*
*
* How many frames in one transmission? (for APRS)
*
* Should we send multiple frames in one transmission if we
* have more than one sitting in the queue? At first I was thinking
* this would help reduce channel congestion. I don't recall seeing
* anything in the APRS specifications allowing or disallowing multiple
* frames in one transmission. I can think of some scenarios
* where it might help. I can think of some where it would
* definitely be counter productive.
*
* What to others have to say about this topic?
*
* "For what it is worth, the original APRSdos used a several second random
* generator each time any kind of packet was generated... This is to avoid
* bundling. Because bundling, though good for connected packet, is not good
* on APRS. Sometimes the digi begins digipeating the first packet in the
* bundle and steps all over the remainder of them. So best to make sure each
* packet is isolated in time from others..."
*
* Bob, WB4APR
*
*
* Version 0.9: Earlier versions always sent one frame per transmission.
* This was fine for APRS but more and more people are now
* using this as a KISS TNC for connected protocols.
* Rather than having a configuration file item,
* we try setting the maximum number automatically.
* 1 for digipeated frames, 7 for others.
*
* Version 1.4: Lift the limit. We could theoretically have a window size up to 127.
* If another section pumps out that many quickly we shouldn't
* break it up here. Empty out both queues with some exceptions.
*
* Digipeated APRS, Speech, and Morse code should have
* their own separate transmissions.
* Everything else can be bundled together.
* Different priorities can share a single transmission.
* Once we have control of the channel, we might as well keep going.
* [High] Priority frames will always go to head of the line,
*
* Version 1.5: Add full duplex option.
*
*--------------------------------------------------------------------*/
static void xmit_ax25_frames (int chan, int prio, packet_t pp, int max_bundle)
{
int pre_flags, post_flags;
int num_bits; /* Total number of bits in transmission */
/* including all flags and bit stuffing. */
int duration; /* Transmission time in milliseconds. */
int already;
int wait_more;
int numframe = 0; /* Number of frames sent during this transmission. */
/*
* These are for timing of a transmission.
* All are in usual unix time (seconds since 1/1/1970) but higher resolution
*/
double time_ptt; /* Time when PTT is turned on. */
double time_now; /* Current time. */
int nb;
/*
* Turn on transmitter.
* Start sending leading flag bytes.
*/
time_ptt = dtime_now ();
// TODO: This was written assuming bits/sec = baud.
// Does it is need to be scaled differently for PSK?
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_thread: t=%.3f, Turn on PTT now for channel %d. speed = %d\n", dtime_now()-time_ptt, chan, xmit_bits_per_sec[chan]);
#endif
ptt_set (OCTYPE_PTT, chan, 1);
// Inform data link state machine that we are now transmitting.
dlq_seize_confirm (chan); // C4.2. "This primitive indicates, to the Data-link State
// machine, that the transmission opportunity has arrived."
pre_flags = MS_TO_BITS(xmit_txdelay[chan] * 10, chan) / 8;
num_bits = layer2_preamble_postamble (chan, pre_flags, 0, save_audio_config_p);
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_thread: t=%.3f, txdelay=%d [*10], pre_flags=%d, num_bits=%d\n", dtime_now()-time_ptt, xmit_txdelay[chan], pre_flags, num_bits);
double presleep = dtime_now();
#endif
SLEEP_MS (10); // Give data link state machine a chance to
// to stuff more frames into the transmit queue,
// in response to dlq_seize_confirm, so
// we don't run off the end too soon.
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
// How long did sleep last?
dw_printf ("xmit_thread: t=%.3f, Should be 0.010 second after the above.\n", dtime_now()-time_ptt);
double naptime = dtime_now() - presleep;
if (naptime > 0.015) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Sleep for 10 ms actually took %.3f second!\n", naptime);
}
#endif
/*
* Transmit the frame.
*/
nb = send_one_frame (chan, prio, pp);
num_bits += nb;
if (nb > 0) numframe++;
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_thread: t=%.3f, nb=%d, num_bits=%d, numframe=%d\n", dtime_now()-time_ptt, nb, num_bits, numframe);
#endif
ax25_delete (pp);
/*
* See if we can bundle additional frames into this transmission.
*/
int done = 0;
while (numframe < max_bundle && ! done) {
/*
* Peek at what is available.
* Don't remove from queue yet because it might not be eligible.
*/
prio = TQ_PRIO_1_LO;
pp = tq_peek (chan, TQ_PRIO_0_HI);
if (pp != NULL) {
prio = TQ_PRIO_0_HI;
}
else {
pp = tq_peek (chan, TQ_PRIO_1_LO);
}
if (pp != NULL) {
switch (frame_flavor(pp)) {
case FLAVOR_SPEECH:
case FLAVOR_MORSE:
case FLAVOR_DTMF:
case FLAVOR_APRS_DIGI:
default:
done = 1; // not eligible for bundling.
break;
case FLAVOR_APRS_NEW:
case FLAVOR_OTHER:
pp = tq_remove (chan, prio);
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_thread: t=%.3f, tq_remove(chan=%d, prio=%d) returned %p\n", dtime_now()-time_ptt, chan, prio, pp);
#endif
nb = send_one_frame (chan, prio, pp);
num_bits += nb;
if (nb > 0) numframe++;
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_thread: t=%.3f, nb=%d, num_bits=%d, numframe=%d\n", dtime_now()-time_ptt, nb, num_bits, numframe);
#endif
ax25_delete (pp);
break;
}
}
else {
done = 1;
}
}
/*
* Need TXTAIL because we don't know exactly when the sound is done.
*/
post_flags = MS_TO_BITS(xmit_txtail[chan] * 10, chan) / 8;
nb = layer2_preamble_postamble (chan, post_flags, 1, save_audio_config_p);
num_bits += nb;
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_thread: t=%.3f, txtail=%d [*10], post_flags=%d, nb=%d, num_bits=%d\n", dtime_now()-time_ptt, xmit_txtail[chan], post_flags, nb, num_bits);
#endif
/*
* While demodulating is CPU intensive, generating the tones is not.
* Example: on the RPi model 1, with 50% of the CPU taken with two receive
* channels, a transmission of more than a second is generated in
* about 40 mS of elapsed real time.
*/
audio_wait(ACHAN2ADEV(chan));
/*
* Ideally we should be here just about the time when the audio is ending.
* However, the innards of "audio_wait" are not satisfactory in all cases.
*
* Calculate how long the frame(s) should take in milliseconds.
*/
duration = BITS_TO_MS(num_bits, chan);
/*
* See how long it has been since PTT was turned on.
* Wait additional time if necessary.
*/
time_now = dtime_now();
already = (int) ((time_now - time_ptt) * 1000.);
wait_more = duration - already;
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("xmit_thread: t=%.3f, xmit duration=%d, %d already elapsed since PTT, wait %d more\n", dtime_now()-time_ptt, duration, already, wait_more );
#endif
if (wait_more > 0) {
SLEEP_MS(wait_more);
}
else if (wait_more < -100) {
/* If we run over by 10 mSec or so, it's nothing to worry about. */
/* However, if PTT is still on about 1/10 sec after audio */
/* should be done, something is wrong. */
/* Looks like a bug with the RPi audio system. Never an issue with Ubuntu. */
/* This runs over randomly sometimes. TODO: investigate more fully sometime. */
#ifndef __arm__
text_color_set(DW_COLOR_ERROR);
dw_printf ("Transmit timing error: PTT is on %d mSec too long.\n", -wait_more);
#endif
}
/*
* Turn off transmitter.
*/
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
time_now = dtime_now();
dw_printf ("xmit_thread: t=%.3f, Turn off PTT now. Actual time on was %d mS, vs. %d desired\n", dtime_now()-time_ptt, (int) ((time_now - time_ptt) * 1000.), duration);
#endif
ptt_set (OCTYPE_PTT, chan, 0);
} /* end xmit_ax25_frames */
/*-------------------------------------------------------------------
*
* Name: send_one_frame
*
* Purpose: Send one AX.25 frame.
*
* Inputs: c - Channel number.
*
* p - Priority.
*
* pp - Packet object pointer. Caller will delete it.
*
* Returns: Number of bits transmitted.
*
* Description: Caller is responsible for activiating PTT, TXDELAY,
* deciding how many frames can be in one transmission,
* deactivating PTT.
*
*--------------------------------------------------------------------*/
static int send_one_frame (int c, int p, packet_t pp)
{
char stemp[1024]; /* max size needed? */
int info_len;
unsigned char *pinfo;
int nb;
if (ax25_is_null_frame(pp)) {
// Issue 132 - We could end up in a situation where:
// Transmitter is already on.
// Application wants to send a frame.
// dl_seize_request turns into this null frame.
// It was being ignored here so the data got stuck in the queue.
// I think the solution is to send back a seize confirm here.
// It shouldn't hurt if we send it redundantly.
// Added for 1.5 beta test 4.
dlq_seize_confirm (c); // C4.2. "This primitive indicates, to the Data-link State
// machine, that the transmission opportunity has arrived."
SLEEP_MS (10); // Give data link state machine a chance to
// to stuff more frames into the transmit queue,
// in response to dlq_seize_confirm, so
// we don't run off the end too soon.
return(0);
}
char ts[100]; // optional time stamp.
if (strlen(save_audio_config_p->timestamp_format) > 0) {
char tstmp[100];
timestamp_user_format (tstmp, sizeof(tstmp), save_audio_config_p->timestamp_format);
strlcpy (ts, " ", sizeof(ts)); // space after channel.
strlcat (ts, tstmp, sizeof(ts));
}