Free Electrons

Embedded Linux Experts

   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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
/*
 *	IrNET protocol module : Synchronous PPP over an IrDA socket.
 *
 *		Jean II - HPL `00 - <jt@hpl.hp.com>
 *
 * This file implement the PPP interface and /dev/irnet character device.
 * The PPP interface hook to the ppp_generic module, handle all our
 *	relationship to the PPP code in the kernel (and by extension to pppd),
 *	and exchange PPP frames with this module (send/receive).
 * The /dev/irnet device is used primarily for 2 functions :
 *	1) as a stub for pppd (the ppp daemon), so that we can appropriately
 *	generate PPP sessions (we pretend we are a tty).
 *	2) as a control channel (write commands, read events)
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include "irnet_ppp.h"		/* Private header */
/* Please put other headers in irnet.h - Thanks */

/* Generic PPP callbacks (to call us) */
static const struct ppp_channel_ops irnet_ppp_ops = {
	.start_xmit = ppp_irnet_send,
	.ioctl = ppp_irnet_ioctl
};

/************************* CONTROL CHANNEL *************************/
/*
 * When a pppd instance is not active on /dev/irnet, it acts as a control
 * channel.
 * Writing allow to set up the IrDA destination of the IrNET channel,
 * and any application may be read events happening in IrNET...
 */

/*------------------------------------------------------------------*/
/*
 * Write is used to send a command to configure a IrNET channel
 * before it is open by pppd. The syntax is : "command argument"
 * Currently there is only two defined commands :
 *	o name : set the requested IrDA nickname of the IrNET peer.
 *	o addr : set the requested IrDA address of the IrNET peer.
 * Note : the code is crude, but effective...
 */
static inline ssize_t
irnet_ctrl_write(irnet_socket *	ap,
		 const char __user *buf,
		 size_t		count)
{
  char		command[IRNET_MAX_COMMAND];
  char *	start;		/* Current command being processed */
  char *	next;		/* Next command to process */
  int		length;		/* Length of current command */

  DENTER(CTRL_TRACE, "(ap=0x%p, count=%Zd)\n", ap, count);

  /* Check for overflow... */
  DABORT(count >= IRNET_MAX_COMMAND, -ENOMEM,
	 CTRL_ERROR, "Too much data !!!\n");

  /* Get the data in the driver */
  if(copy_from_user(command, buf, count))
    {
      DERROR(CTRL_ERROR, "Invalid user space pointer.\n");
      return -EFAULT;
    }

  /* Safe terminate the string */
  command[count] = '\0';
  DEBUG(CTRL_INFO, "Command line received is ``%s'' (%Zd).\n",
	command, count);

  /* Check every commands in the command line */
  next = command;
  while(next != NULL)
    {
      /* Look at the next command */
      start = next;

	/* Scrap whitespaces before the command */
	start = skip_spaces(start);

      /* ',' is our command separator */
      next = strchr(start, ',');
      if(next)
	{
	  *next = '\0';			/* Terminate command */
	  length = next - start;	/* Length */
	  next++;			/* Skip the '\0' */
	}
      else
	length = strlen(start);

      DEBUG(CTRL_INFO, "Found command ``%s'' (%d).\n", start, length);

      /* Check if we recognised one of the known command
       * We can't use "switch" with strings, so hack with "continue" */

      /* First command : name -> Requested IrDA nickname */
      if(!strncmp(start, "name", 4))
	{
	  /* Copy the name only if is included and not "any" */
	  if((length > 5) && (strcmp(start + 5, "any")))
	    {
	      /* Strip out trailing whitespaces */
	      while(isspace(start[length - 1]))
		length--;

	      DABORT(length < 5 || length > NICKNAME_MAX_LEN + 5,
		     -EINVAL, CTRL_ERROR, "Invalid nickname.\n");

	      /* Copy the name for later reuse */
	      memcpy(ap->rname, start + 5, length - 5);
	      ap->rname[length - 5] = '\0';
	    }
	  else
	    ap->rname[0] = '\0';
	  DEBUG(CTRL_INFO, "Got rname = ``%s''\n", ap->rname);

	  /* Restart the loop */
	  continue;
	}

      /* Second command : addr, daddr -> Requested IrDA destination address
       * Also process : saddr -> Requested IrDA source address */
      if((!strncmp(start, "addr", 4)) ||
	 (!strncmp(start, "daddr", 5)) ||
	 (!strncmp(start, "saddr", 5)))
	{
	  __u32		addr = DEV_ADDR_ANY;

	  /* Copy the address only if is included and not "any" */
	  if((length > 5) && (strcmp(start + 5, "any")))
	    {
	      char *	begp = start + 5;
	      char *	endp;

	      /* Scrap whitespaces before the command */
	      begp = skip_spaces(begp);

	      /* Convert argument to a number (last arg is the base) */
	      addr = simple_strtoul(begp, &endp, 16);
	      /* Has it worked  ? (endp should be start + length) */
	      DABORT(endp <= (start + 5), -EINVAL,
		     CTRL_ERROR, "Invalid address.\n");
	    }
	  /* Which type of address ? */
	  if(start[0] == 's')
	    {
	      /* Save it */
	      ap->rsaddr = addr;
	      DEBUG(CTRL_INFO, "Got rsaddr = %08x\n", ap->rsaddr);
	    }
	  else
	    {
	      /* Save it */
	      ap->rdaddr = addr;
	      DEBUG(CTRL_INFO, "Got rdaddr = %08x\n", ap->rdaddr);
	    }

	  /* Restart the loop */
	  continue;
	}

      /* Other possible command : connect N (number of retries) */

      /* No command matched -> Failed... */
      DABORT(1, -EINVAL, CTRL_ERROR, "Not a recognised IrNET command.\n");
    }

  /* Success : we have parsed all commands successfully */
  return count;
}

#ifdef INITIAL_DISCOVERY
/*------------------------------------------------------------------*/
/*
 * Function irnet_get_discovery_log (self)
 *
 *    Query the content on the discovery log if not done
 *
 * This function query the current content of the discovery log
 * at the startup of the event channel and save it in the internal struct.
 */
static void
irnet_get_discovery_log(irnet_socket *	ap)
{
  __u16		mask = irlmp_service_to_hint(S_LAN);

  /* Ask IrLMP for the current discovery log */
  ap->discoveries = irlmp_get_discoveries(&ap->disco_number, mask,
					  DISCOVERY_DEFAULT_SLOTS);

  /* Check if the we got some results */
  if(ap->discoveries == NULL)
    ap->disco_number = -1;

  DEBUG(CTRL_INFO, "Got the log (0x%p), size is %d\n",
	ap->discoveries, ap->disco_number);
}

/*------------------------------------------------------------------*/
/*
 * Function irnet_read_discovery_log (self, event)
 *
 *    Read the content on the discovery log
 *
 * This function dump the current content of the discovery log
 * at the startup of the event channel.
 * Return 1 if wrote an event on the control channel...
 *
 * State of the ap->disco_XXX variables :
 * Socket creation :  discoveries = NULL ; disco_index = 0 ; disco_number = 0
 * While reading :    discoveries = ptr  ; disco_index = X ; disco_number = Y
 * After reading :    discoveries = NULL ; disco_index = Y ; disco_number = -1
 */
static inline int
irnet_read_discovery_log(irnet_socket *	ap,
			 char *		event)
{
  int		done_event = 0;

  DENTER(CTRL_TRACE, "(ap=0x%p, event=0x%p)\n",
	 ap, event);

  /* Test if we have some work to do or we have already finished */
  if(ap->disco_number == -1)
    {
      DEBUG(CTRL_INFO, "Already done\n");
      return 0;
    }

  /* Test if it's the first time and therefore we need to get the log */
  if(ap->discoveries == NULL)
    irnet_get_discovery_log(ap);

  /* Check if we have more item to dump */
  if(ap->disco_index < ap->disco_number)
    {
      /* Write an event */
      sprintf(event, "Found %08x (%s) behind %08x {hints %02X-%02X}\n",
	      ap->discoveries[ap->disco_index].daddr,
	      ap->discoveries[ap->disco_index].info,
	      ap->discoveries[ap->disco_index].saddr,
	      ap->discoveries[ap->disco_index].hints[0],
	      ap->discoveries[ap->disco_index].hints[1]);
      DEBUG(CTRL_INFO, "Writing discovery %d : %s\n",
	    ap->disco_index, ap->discoveries[ap->disco_index].info);

      /* We have an event */
      done_event = 1;
      /* Next discovery */
      ap->disco_index++;
    }

  /* Check if we have done the last item */
  if(ap->disco_index >= ap->disco_number)
    {
      /* No more items : remove the log and signal termination */
      DEBUG(CTRL_INFO, "Cleaning up log (0x%p)\n",
	    ap->discoveries);
      if(ap->discoveries != NULL)
	{
	  /* Cleanup our copy of the discovery log */
	  kfree(ap->discoveries);
	  ap->discoveries = NULL;
	}
      ap->disco_number = -1;
    }

  return done_event;
}
#endif /* INITIAL_DISCOVERY */

/*------------------------------------------------------------------*/
/*
 * Read is used to get IrNET events
 */
static inline ssize_t
irnet_ctrl_read(irnet_socket *	ap,
		struct file *	file,
		char __user *	buf,
		size_t		count)
{
  DECLARE_WAITQUEUE(wait, current);
  char		event[64];	/* Max event is 61 char */
  ssize_t	ret = 0;

  DENTER(CTRL_TRACE, "(ap=0x%p, count=%Zd)\n", ap, count);

  /* Check if we can write an event out in one go */
  DABORT(count < sizeof(event), -EOVERFLOW, CTRL_ERROR, "Buffer to small.\n");

#ifdef INITIAL_DISCOVERY
  /* Check if we have read the log */
  if(irnet_read_discovery_log(ap, event))
    {
      /* We have an event !!! Copy it to the user */
      if(copy_to_user(buf, event, strlen(event)))
	{
	  DERROR(CTRL_ERROR, "Invalid user space pointer.\n");
	  return -EFAULT;
	}

      DEXIT(CTRL_TRACE, "\n");
      return strlen(event);
    }
#endif /* INITIAL_DISCOVERY */

  /* Put ourselves on the wait queue to be woken up */
  add_wait_queue(&irnet_events.rwait, &wait);
  current->state = TASK_INTERRUPTIBLE;
  for(;;)
    {
      /* If there is unread events */
      ret = 0;
      if(ap->event_index != irnet_events.index)
	break;
      ret = -EAGAIN;
      if(file->f_flags & O_NONBLOCK)
	break;
      ret = -ERESTARTSYS;
      if(signal_pending(current))
	break;
      /* Yield and wait to be woken up */
      schedule();
    }
  current->state = TASK_RUNNING;
  remove_wait_queue(&irnet_events.rwait, &wait);

  /* Did we got it ? */
  if(ret != 0)
    {
      /* No, return the error code */
      DEXIT(CTRL_TRACE, " - ret %Zd\n", ret);
      return ret;
    }

  /* Which event is it ? */
  switch(irnet_events.log[ap->event_index].event)
    {
    case IRNET_DISCOVER:
      sprintf(event, "Discovered %08x (%s) behind %08x {hints %02X-%02X}\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].saddr,
	      irnet_events.log[ap->event_index].hints.byte[0],
	      irnet_events.log[ap->event_index].hints.byte[1]);
      break;
    case IRNET_EXPIRE:
      sprintf(event, "Expired %08x (%s) behind %08x {hints %02X-%02X}\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].saddr,
	      irnet_events.log[ap->event_index].hints.byte[0],
	      irnet_events.log[ap->event_index].hints.byte[1]);
      break;
    case IRNET_CONNECT_TO:
      sprintf(event, "Connected to %08x (%s) on ppp%d\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].unit);
      break;
    case IRNET_CONNECT_FROM:
      sprintf(event, "Connection from %08x (%s) on ppp%d\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].unit);
      break;
    case IRNET_REQUEST_FROM:
      sprintf(event, "Request from %08x (%s) behind %08x\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].saddr);
      break;
    case IRNET_NOANSWER_FROM:
      sprintf(event, "No-answer from %08x (%s) on ppp%d\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].unit);
      break;
    case IRNET_BLOCKED_LINK:
      sprintf(event, "Blocked link with %08x (%s) on ppp%d\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].unit);
      break;
    case IRNET_DISCONNECT_FROM:
      sprintf(event, "Disconnection from %08x (%s) on ppp%d\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name,
	      irnet_events.log[ap->event_index].unit);
      break;
    case IRNET_DISCONNECT_TO:
      sprintf(event, "Disconnected to %08x (%s)\n",
	      irnet_events.log[ap->event_index].daddr,
	      irnet_events.log[ap->event_index].name);
      break;
    default:
      sprintf(event, "Bug\n");
    }
  /* Increment our event index */
  ap->event_index = (ap->event_index + 1) % IRNET_MAX_EVENTS;

  DEBUG(CTRL_INFO, "Event is :%s", event);

  /* Copy it to the user */
  if(copy_to_user(buf, event, strlen(event)))
    {
      DERROR(CTRL_ERROR, "Invalid user space pointer.\n");
      return -EFAULT;
    }

  DEXIT(CTRL_TRACE, "\n");
  return strlen(event);
}

/*------------------------------------------------------------------*/
/*
 * Poll : called when someone do a select on /dev/irnet.
 * Just check if there are new events...
 */
static inline unsigned int
irnet_ctrl_poll(irnet_socket *	ap,
		struct file *	file,
		poll_table *	wait)
{
  unsigned int mask;

  DENTER(CTRL_TRACE, "(ap=0x%p)\n", ap);

  poll_wait(file, &irnet_events.rwait, wait);
  mask = POLLOUT | POLLWRNORM;
  /* If there is unread events */
  if(ap->event_index != irnet_events.index)
    mask |= POLLIN | POLLRDNORM;
#ifdef INITIAL_DISCOVERY
  if(ap->disco_number != -1)
    {
      /* Test if it's the first time and therefore we need to get the log */
      if(ap->discoveries == NULL)
	irnet_get_discovery_log(ap);
      /* Recheck */
      if(ap->disco_number != -1)
	mask |= POLLIN | POLLRDNORM;
    }
#endif /* INITIAL_DISCOVERY */

  DEXIT(CTRL_TRACE, " - mask=0x%X\n", mask);
  return mask;
}


/*********************** FILESYSTEM CALLBACKS ***********************/
/*
 * Implement the usual open, read, write functions that will be called
 * by the file system when some action is performed on /dev/irnet.
 * Most of those actions will in fact be performed by "pppd" or
 * the control channel, we just act as a redirector...
 */

/*------------------------------------------------------------------*/
/*
 * Open : when somebody open /dev/irnet
 * We basically create a new instance of irnet and initialise it.
 */
static int
dev_irnet_open(struct inode *	inode,
	       struct file *	file)
{
  struct irnet_socket *	ap;
  int			err;

  DENTER(FS_TRACE, "(file=0x%p)\n", file);

#ifdef SECURE_DEVIRNET
  /* This could (should?) be enforced by the permissions on /dev/irnet. */
  if(!capable(CAP_NET_ADMIN))
    return -EPERM;
#endif /* SECURE_DEVIRNET */

  /* Allocate a private structure for this IrNET instance */
  ap = kzalloc(sizeof(*ap), GFP_KERNEL);
  DABORT(ap == NULL, -ENOMEM, FS_ERROR, "Can't allocate struct irnet...\n");

  /* initialize the irnet structure */
  ap->file = file;

  /* PPP channel setup */
  ap->ppp_open = 0;
  ap->chan.private = ap;
  ap->chan.ops = &irnet_ppp_ops;
  ap->chan.mtu = (2048 - TTP_MAX_HEADER - 2 - PPP_HDRLEN);
  ap->chan.hdrlen = 2 + TTP_MAX_HEADER;		/* for A/C + Max IrDA hdr */
  /* PPP parameters */
  ap->mru = (2048 - TTP_MAX_HEADER - 2 - PPP_HDRLEN);
  ap->xaccm[0] = ~0U;
  ap->xaccm[3] = 0x60000000U;
  ap->raccm = ~0U;

  /* Setup the IrDA part... */
  err = irda_irnet_create(ap);
  if(err)
    {
      DERROR(FS_ERROR, "Can't setup IrDA link...\n");
      kfree(ap);

      return err;
    }

  /* For the control channel */
  ap->event_index = irnet_events.index;	/* Cancel all past events */

  mutex_init(&ap->lock);

  /* Put our stuff where we will be able to find it later */
  file->private_data = ap;

  DEXIT(FS_TRACE, " - ap=0x%p\n", ap);

  return 0;
}


/*------------------------------------------------------------------*/
/*
 * Close : when somebody close /dev/irnet
 * Destroy the instance of /dev/irnet
 */
static int
dev_irnet_close(struct inode *	inode,
		struct file *	file)
{
  irnet_socket *	ap = file->private_data;

  DENTER(FS_TRACE, "(file=0x%p, ap=0x%p)\n",
	 file, ap);
  DABORT(ap == NULL, 0, FS_ERROR, "ap is NULL !!!\n");

  /* Detach ourselves */
  file->private_data = NULL;

  /* Close IrDA stuff */
  irda_irnet_destroy(ap);

  /* Disconnect from the generic PPP layer if not already done */
  if(ap->ppp_open)
    {
      DERROR(FS_ERROR, "Channel still registered - deregistering !\n");
      ap->ppp_open = 0;
      ppp_unregister_channel(&ap->chan);
    }

  kfree(ap);

  DEXIT(FS_TRACE, "\n");
  return 0;
}

/*------------------------------------------------------------------*/
/*
 * Write does nothing.
 * (we receive packet from ppp_generic through ppp_irnet_send())
 */
static ssize_t
dev_irnet_write(struct file *	file,
		const char __user *buf,
		size_t		count,
		loff_t *	ppos)
{
  irnet_socket *	ap = file->private_data;

  DPASS(FS_TRACE, "(file=0x%p, ap=0x%p, count=%Zd)\n",
	file, ap, count);
  DABORT(ap == NULL, -ENXIO, FS_ERROR, "ap is NULL !!!\n");

  /* If we are connected to ppp_generic, let it handle the job */
  if(ap->ppp_open)
    return -EAGAIN;
  else
    return irnet_ctrl_write(ap, buf, count);
}

/*------------------------------------------------------------------*/
/*
 * Read doesn't do much either.
 * (pppd poll us, but ultimately reads through /dev/ppp)
 */
static ssize_t
dev_irnet_read(struct file *	file,
	       char __user *	buf,
	       size_t		count,
	       loff_t *		ppos)
{
  irnet_socket *	ap = file->private_data;

  DPASS(FS_TRACE, "(file=0x%p, ap=0x%p, count=%Zd)\n",
	file, ap, count);
  DABORT(ap == NULL, -ENXIO, FS_ERROR, "ap is NULL !!!\n");

  /* If we are connected to ppp_generic, let it handle the job */
  if(ap->ppp_open)
    return -EAGAIN;
  else
    return irnet_ctrl_read(ap, file, buf, count);
}

/*------------------------------------------------------------------*/
/*
 * Poll : called when someone do a select on /dev/irnet
 */
static unsigned int
dev_irnet_poll(struct file *	file,
	       poll_table *	wait)
{
  irnet_socket *	ap = file->private_data;
  unsigned int		mask;

  DENTER(FS_TRACE, "(file=0x%p, ap=0x%p)\n",
	 file, ap);

  mask = POLLOUT | POLLWRNORM;
  DABORT(ap == NULL, mask, FS_ERROR, "ap is NULL !!!\n");

  /* If we are connected to ppp_generic, let it handle the job */
  if(!ap->ppp_open)
    mask |= irnet_ctrl_poll(ap, file, wait);

  DEXIT(FS_TRACE, " - mask=0x%X\n", mask);
  return mask;
}

/*------------------------------------------------------------------*/
/*
 * IOCtl : Called when someone does some ioctls on /dev/irnet
 * This is the way pppd configure us and control us while the PPP
 * instance is active.
 */
static long
dev_irnet_ioctl(
		struct file *	file,
		unsigned int	cmd,
		unsigned long	arg)
{
  irnet_socket *	ap = file->private_data;
  int			err;
  int			val;
  void __user *argp = (void __user *)arg;

  DENTER(FS_TRACE, "(file=0x%p, ap=0x%p, cmd=0x%X)\n",
	 file, ap, cmd);

  /* Basic checks... */
  DASSERT(ap != NULL, -ENXIO, PPP_ERROR, "ap is NULL...\n");
#ifdef SECURE_DEVIRNET
  if(!capable(CAP_NET_ADMIN))
    return -EPERM;
#endif /* SECURE_DEVIRNET */

  err = -EFAULT;
  switch(cmd)
    {
      /* Set discipline (should be N_SYNC_PPP or N_TTY) */
    case TIOCSETD:
      if(get_user(val, (int __user *)argp))
	break;
      if((val == N_SYNC_PPP) || (val == N_PPP))
	{
	  DEBUG(FS_INFO, "Entering PPP discipline.\n");
	  /* PPP channel setup (ap->chan in configured in dev_irnet_open())*/
	  if (mutex_lock_interruptible(&ap->lock))
		  return -EINTR;

	  err = ppp_register_channel(&ap->chan);
	  if(err == 0)
	    {
	      /* Our ppp side is active */
	      ap->ppp_open = 1;

	      DEBUG(FS_INFO, "Trying to establish a connection.\n");
	      /* Setup the IrDA link now - may fail... */
	      irda_irnet_connect(ap);
	    }
	  else
	    DERROR(FS_ERROR, "Can't setup PPP channel...\n");

          mutex_unlock(&ap->lock);
	}
      else
	{
	  /* In theory, should be N_TTY */
	  DEBUG(FS_INFO, "Exiting PPP discipline.\n");
	  /* Disconnect from the generic PPP layer */
	  if (mutex_lock_interruptible(&ap->lock))
		  return -EINTR;

	  if(ap->ppp_open)
	    {
	      ap->ppp_open = 0;
	      ppp_unregister_channel(&ap->chan);
	    }
	  else
	    DERROR(FS_ERROR, "Channel not registered !\n");
	  err = 0;

	  mutex_unlock(&ap->lock);
	}
      break;

      /* Query PPP channel and unit number */
    case PPPIOCGCHAN:
      if (mutex_lock_interruptible(&ap->lock))
	      return -EINTR;

      if(ap->ppp_open && !put_user(ppp_channel_index(&ap->chan),
						(int __user *)argp))
	err = 0;

      mutex_unlock(&ap->lock);
      break;
    case PPPIOCGUNIT:
      if (mutex_lock_interruptible(&ap->lock))
	      return -EINTR;

      if(ap->ppp_open && !put_user(ppp_unit_number(&ap->chan),
						(int __user *)argp))
        err = 0;

      mutex_unlock(&ap->lock);
      break;

      /* All these ioctls can be passed both directly and from ppp_generic,
       * so we just deal with them in one place...
       */
    case PPPIOCGFLAGS:
    case PPPIOCSFLAGS:
    case PPPIOCGASYNCMAP:
    case PPPIOCSASYNCMAP:
    case PPPIOCGRASYNCMAP:
    case PPPIOCSRASYNCMAP:
    case PPPIOCGXASYNCMAP:
    case PPPIOCSXASYNCMAP:
    case PPPIOCGMRU:
    case PPPIOCSMRU:
      DEBUG(FS_INFO, "Standard PPP ioctl.\n");
      if(!capable(CAP_NET_ADMIN))
	err = -EPERM;
      else {
	if (mutex_lock_interruptible(&ap->lock))
	      return -EINTR;

	err = ppp_irnet_ioctl(&ap->chan, cmd, arg);

	mutex_unlock(&ap->lock);
      }
      break;

      /* TTY IOCTLs : Pretend that we are a tty, to keep pppd happy */
      /* Get termios */
    case TCGETS:
      DEBUG(FS_INFO, "Get termios.\n");
      if (mutex_lock_interruptible(&ap->lock))
	      return -EINTR;

#ifndef TCGETS2
      if(!kernel_termios_to_user_termios((struct termios __user *)argp, &ap->termios))
	err = 0;
#else
      if(kernel_termios_to_user_termios_1((struct termios __user *)argp, &ap->termios))
	err = 0;
#endif

      mutex_unlock(&ap->lock);
      break;
      /* Set termios */
    case TCSETSF:
      DEBUG(FS_INFO, "Set termios.\n");
      if (mutex_lock_interruptible(&ap->lock))
	      return -EINTR;

#ifndef TCGETS2
      if(!user_termios_to_kernel_termios(&ap->termios, (struct termios __user *)argp))
	err = 0;
#else
      if(!user_termios_to_kernel_termios_1(&ap->termios, (struct termios __user *)argp))
	err = 0;
#endif

      mutex_unlock(&ap->lock);
      break;

      /* Set DTR/RTS */
    case TIOCMBIS:
    case TIOCMBIC:
      /* Set exclusive/non-exclusive mode */
    case TIOCEXCL:
    case TIOCNXCL:
      DEBUG(FS_INFO, "TTY compatibility.\n");
      err = 0;
      break;

    case TCGETA:
      DEBUG(FS_INFO, "TCGETA\n");
      break;

    case TCFLSH:
      DEBUG(FS_INFO, "TCFLSH\n");
      /* Note : this will flush buffers in PPP, so it *must* be done
       * We should also worry that we don't accept junk here and that
       * we get rid of our own buffers */
#ifdef FLUSH_TO_PPP
      if (mutex_lock_interruptible(&ap->lock))
	      return -EINTR;
      ppp_output_wakeup(&ap->chan);
      mutex_unlock(&ap->lock);
#endif /* FLUSH_TO_PPP */
      err = 0;
      break;

    case FIONREAD:
      DEBUG(FS_INFO, "FIONREAD\n");
      val = 0;
      if(put_user(val, (int __user *)argp))
	break;
      err = 0;
      break;

    default:
      DERROR(FS_ERROR, "Unsupported ioctl (0x%X)\n", cmd);
      err = -ENOTTY;
    }

  DEXIT(FS_TRACE, " - err = 0x%X\n", err);
  return err;
}

/************************** PPP CALLBACKS **************************/
/*
 * This are the functions that the generic PPP driver in the kernel
 * will call to communicate to us.
 */

/*------------------------------------------------------------------*/
/*
 * Prepare the ppp frame for transmission over the IrDA socket.
 * We make sure that the header space is enough, and we change ppp header
 * according to flags passed by pppd.
 * This is not a callback, but just a helper function used in ppp_irnet_send()
 */
static inline struct sk_buff *
irnet_prepare_skb(irnet_socket *	ap,
		  struct sk_buff *	skb)
{
  unsigned char *	data;
  int			proto;		/* PPP protocol */
  int			islcp;		/* Protocol == LCP */
  int			needaddr;	/* Need PPP address */

  DENTER(PPP_TRACE, "(ap=0x%p, skb=0x%p)\n",
	 ap, skb);

  /* Extract PPP protocol from the frame */
  data  = skb->data;
  proto = (data[0] << 8) + data[1];

  /* LCP packets with codes between 1 (configure-request)
   * and 7 (code-reject) must be sent as though no options
   * have been negotiated. */
  islcp = (proto == PPP_LCP) && (1 <= data[2]) && (data[2] <= 7);

  /* compress protocol field if option enabled */
  if((data[0] == 0) && (ap->flags & SC_COMP_PROT) && (!islcp))
    skb_pull(skb,1);

  /* Check if we need address/control fields */
  needaddr = 2*((ap->flags & SC_COMP_AC) == 0 || islcp);

  /* Is the skb headroom large enough to contain all IrDA-headers? */
  if((skb_headroom(skb) < (ap->max_header_size + needaddr)) ||
      (skb_shared(skb)))
    {
      struct sk_buff *	new_skb;

      DEBUG(PPP_INFO, "Reallocating skb\n");

      /* Create a new skb */
      new_skb = skb_realloc_headroom(skb, ap->max_header_size + needaddr);

      /* We have to free the original skb anyway */
      dev_kfree_skb(skb);

      /* Did the realloc succeed ? */
      DABORT(new_skb == NULL, NULL, PPP_ERROR, "Could not realloc skb\n");

      /* Use the new skb instead */
      skb = new_skb;
    }

  /* prepend address/control fields if necessary */
  if(needaddr)
    {
      skb_push(skb, 2);
      skb->data[0] = PPP_ALLSTATIONS;
      skb->data[1] = PPP_UI;
    }

  DEXIT(PPP_TRACE, "\n");

  return skb;
}

/*------------------------------------------------------------------*/
/*
 * Send a packet to the peer over the IrTTP connection.
 * Returns 1 iff the packet was accepted.
 * Returns 0 iff packet was not consumed.
 * If the packet was not accepted, we will call ppp_output_wakeup
 * at some later time to reactivate flow control in ppp_generic.
 */
static int
ppp_irnet_send(struct ppp_channel *	chan,
	       struct sk_buff *		skb)
{
  irnet_socket *	self = (struct irnet_socket *) chan->private;
  int			ret;

  DENTER(PPP_TRACE, "(channel=0x%p, ap/self=0x%p)\n",
	 chan, self);

  /* Check if things are somewhat valid... */
  DASSERT(self != NULL, 0, PPP_ERROR, "Self is NULL !!!\n");

  /* Check if we are connected */
  if(!(test_bit(0, &self->ttp_open)))
    {
#ifdef CONNECT_IN_SEND
      /* Let's try to connect one more time... */
      /* Note : we won't be connected after this call, but we should be
       * ready for next packet... */
      /* If we are already connecting, this will fail */
      irda_irnet_connect(self);
#endif /* CONNECT_IN_SEND */

      DEBUG(PPP_INFO, "IrTTP not ready ! (%ld-%ld)\n",
	    self->ttp_open, self->ttp_connect);

      /* Note : we can either drop the packet or block the packet.
       *
       * Blocking the packet allow us a better connection time,
       * because by calling ppp_output_wakeup() we can have
       * ppp_generic resending the LCP request immediately to us,
       * rather than waiting for one of pppd periodic transmission of
       * LCP request.
       *
       * On the other hand, if we block all packet, all those periodic
       * transmissions of pppd accumulate in ppp_generic, creating a
       * backlog of LCP request. When we eventually connect later on,
       * we have to transmit all this backlog before we can connect
       * proper (if we don't timeout before).
       *
       * The current strategy is as follow :
       * While we are attempting to connect, we block packets to get
       * a better connection time.
       * If we fail to connect, we drain the queue and start dropping packets
       */
#ifdef BLOCK_WHEN_CONNECT
      /* If we are attempting to connect */
      if(test_bit(0, &self->ttp_connect))
	{
	  /* Blocking packet, ppp_generic will retry later */
	  return 0;
	}
#endif /* BLOCK_WHEN_CONNECT */

      /* Dropping packet, pppd will retry later */
      dev_kfree_skb(skb);
      return 1;
    }

  /* Check if the queue can accept any packet, otherwise block */
  if(self->tx_flow != FLOW_START)
    DRETURN(0, PPP_INFO, "IrTTP queue full (%d skbs)...\n",
	    skb_queue_len(&self->tsap->tx_queue));

  /* Prepare ppp frame for transmission */
  skb = irnet_prepare_skb(self, skb);
  DABORT(skb == NULL, 1, PPP_ERROR, "Prepare skb for Tx failed.\n");

  /* Send the packet to IrTTP */
  ret = irttp_data_request(self->tsap, skb);
  if(ret < 0)
    {
      /*
       * > IrTTPs tx queue is full, so we just have to
       * > drop the frame! You might think that we should
       * > just return -1 and don't deallocate the frame,
       * > but that is dangerous since it's possible that
       * > we have replaced the original skb with a new
       * > one with larger headroom, and that would really
       * > confuse do_dev_queue_xmit() in dev.c! I have
       * > tried :-) DB
       * Correction : we verify the flow control above (self->tx_flow),
       * so we come here only if IrTTP doesn't like the packet (empty,
       * too large, IrTTP not connected). In those rare cases, it's ok
       * to drop it, we don't want to see it here again...
       * Jean II
       */
      DERROR(PPP_ERROR, "IrTTP doesn't like this packet !!! (0x%X)\n", ret);
      /* irttp_data_request already free the packet */
    }

  DEXIT(PPP_TRACE, "\n");
  return 1;	/* Packet has been consumed */
}

/*------------------------------------------------------------------*/
/*
 * Take care of the ioctls that ppp_generic doesn't want to deal with...
 * Note : we are also called from dev_irnet_ioctl().
 */
static int
ppp_irnet_ioctl(struct ppp_channel *	chan,
		unsigned int		cmd,
		unsigned long		arg)
{
  irnet_socket *	ap = (struct irnet_socket *) chan->private;
  int			err;
  int			val;
  u32			accm[8];
  void __user *argp = (void __user *)arg;

  DENTER(PPP_TRACE, "(channel=0x%p, ap=0x%p, cmd=0x%X)\n",
	 chan, ap, cmd);

  /* Basic checks... */
  DASSERT(ap != NULL, -ENXIO, PPP_ERROR, "ap is NULL...\n");

  err = -EFAULT;
  switch(cmd)
    {
      /* PPP flags */
    case PPPIOCGFLAGS:
      val = ap->flags | ap->rbits;
      if(put_user(val, (int __user *) argp))
	break;
      err = 0;
      break;
    case PPPIOCSFLAGS:
      if(get_user(val, (int __user *) argp))
	break;
      ap->flags = val & ~SC_RCV_BITS;
      ap->rbits = val & SC_RCV_BITS;
      err = 0;
      break;

      /* Async map stuff - all dummy to please pppd */
    case PPPIOCGASYNCMAP:
      if(put_user(ap->xaccm[0], (u32 __user *) argp))
	break;
      err = 0;
      break;
    case PPPIOCSASYNCMAP:
      if(get_user(ap->xaccm[0], (u32 __user *) argp))
	break;
      err = 0;
      break;
    case PPPIOCGRASYNCMAP:
      if(put_user(ap->raccm, (u32 __user *) argp))
	break;
      err = 0;
      break;
    case PPPIOCSRASYNCMAP:
      if(get_user(ap->raccm, (u32 __user *) argp))
	break;
      err = 0;
      break;
    case PPPIOCGXASYNCMAP:
      if(copy_to_user(argp, ap->xaccm, sizeof(ap->xaccm)))
	break;
      err = 0;
      break;
    case PPPIOCSXASYNCMAP:
      if(copy_from_user(accm, argp, sizeof(accm)))
	break;
      accm[2] &= ~0x40000000U;		/* can't escape 0x5e */
      accm[3] |= 0x60000000U;		/* must escape 0x7d, 0x7e */
      memcpy(ap->xaccm, accm, sizeof(ap->xaccm));
      err = 0;
      break;

      /* Max PPP frame size */
    case PPPIOCGMRU:
      if(put_user(ap->mru, (int __user *) argp))
	break;
      err = 0;
      break;
    case PPPIOCSMRU:
      if(get_user(val, (int __user *) argp))
	break;
      if(val < PPP_MRU)
	val = PPP_MRU;
      ap->mru = val;
      err = 0;
      break;

    default:
      DEBUG(PPP_INFO, "Unsupported ioctl (0x%X)\n", cmd);
      err = -ENOIOCTLCMD;
    }

  DEXIT(PPP_TRACE, " - err = 0x%X\n", err);
  return err;
}

/************************** INITIALISATION **************************/
/*
 * Module initialisation and all that jazz...
 */

/*------------------------------------------------------------------*/
/*
 * Hook our device callbacks in the filesystem, to connect our code
 * to /dev/irnet
 */
static inline int __init
ppp_irnet_init(void)
{
  int err = 0;

  DENTER(MODULE_TRACE, "()\n");

  /* Allocate ourselves as a minor in the misc range */
  err = misc_register(&irnet_misc_device);

  DEXIT(MODULE_TRACE, "\n");
  return err;
}

/*------------------------------------------------------------------*/
/*
 * Cleanup at exit...
 */
static inline void __exit
ppp_irnet_cleanup(void)
{
  DENTER(MODULE_TRACE, "()\n");

  /* De-allocate /dev/irnet minor in misc range */
  misc_deregister(&irnet_misc_device);

  DEXIT(MODULE_TRACE, "\n");
}

/*------------------------------------------------------------------*/
/*
 * Module main entry point
 */
static int __init
irnet_init(void)
{
  int err;

  /* Initialise both parts... */
  err = irda_irnet_init();
  if(!err)
    err = ppp_irnet_init();
  return err;
}

/*------------------------------------------------------------------*/
/*
 * Module exit
 */
static void __exit
irnet_cleanup(void)
{
  irda_irnet_cleanup();
  ppp_irnet_cleanup();
}

/*------------------------------------------------------------------*/
/*
 * Module magic
 */
module_init(irnet_init);
module_exit(irnet_cleanup);
MODULE_AUTHOR("Jean Tourrilhes <jt@hpl.hp.com>");
MODULE_DESCRIPTION("IrNET : Synchronous PPP over IrDA");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV(10, 187);