net/lapb/lapb_in.c

   1 /*
   2  *      LAPB release 002
   3  *
   4  *      This code REQUIRES 2.1.15 or higher/ NET3.038
   5  *
   6  *      This module:
   7  *              This module is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              as published by the Free Software Foundation; either version
  10  *              2 of the License, or (at your option) any later version.
  11  *
  12  *      History
  13  *      LAPB 001        Jonathan Naulor Started Coding
  14  *      LAPB 002        Jonathan Naylor New timer architecture.
  15  *      2000-10-29      Henner Eisen    lapb_data_indication() return status.
  16  */
  17
  18 #include <linux/errno.h>
  19 #include <linux/types.h>
  20 #include <linux/socket.h>
  21 #include <linux/in.h>
  22 #include <linux/kernel.h>
  23 #include <linux/timer.h>
  24 #include <linux/string.h>
  25 #include <linux/sockios.h>
  26 #include <linux/net.h>
  27 #include <linux/inet.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/skbuff.h>
  30 #include <net/sock.h>
  31 #include <asm/uaccess.h>
  32 #include <asm/system.h>
  33 #include <linux/fcntl.h>
  34 #include <linux/mm.h>
  35 #include <linux/interrupt.h>
  36 #include <net/lapb.h>
  37
  38 /*
  39  *      State machine for state 0, Disconnected State.
  40  *      The handling of the timer(s) is in file lapb_timer.c.
  41  */
  42 static void lapb_state0_machine(struct lapb_cb *lapb, struct sk_buff *skb,
  43                                 struct lapb_frame *frame)
  44 {
  45         switch (frame->type) {
  46                 case LAPB_SABM:
  47 #if LAPB_DEBUG > 1
  48                         printk(KERN_DEBUG "lapb: (%p) S0 RX SABM(%d)\n",
  49                                lapb->dev, frame->pf);
  50 #endif
  51                         if (lapb->mode & LAPB_EXTENDED) {
  52 #if LAPB_DEBUG > 1
  53                                 printk(KERN_DEBUG "lapb: (%p) S0 TX DM(%d)\n",
  54                                        lapb->dev, frame->pf);
  55 #endif
  56                                 lapb_send_control(lapb, LAPB_DM, frame->pf,
  57                                                   LAPB_RESPONSE);
  58                         } else {
  59 #if LAPB_DEBUG > 1
  60                                 printk(KERN_DEBUG "lapb: (%p) S0 TX UA(%d)\n",
  61                                        lapb->dev, frame->pf);
  62 #endif
  63 #if LAPB_DEBUG > 0
  64                                 printk(KERN_DEBUG "lapb: (%p) S0 -> S3\n",
  65                                        lapb->dev);
  66 #endif
  67                                 lapb_send_control(lapb, LAPB_UA, frame->pf,
  68                                                   LAPB_RESPONSE);
  69                                 lapb_stop_t1timer(lapb);
  70                                 lapb_stop_t2timer(lapb);
  71                                 lapb->state     = LAPB_STATE_3;
  72                                 lapb->condition = 0x00;
  73                                 lapb->n2count   = 0;
  74                                 lapb->vs        = 0;
  75                                 lapb->vr        = 0;
  76                                 lapb->va        = 0;
  77                                 lapb_connect_indication(lapb, LAPB_OK);
  78                         }
  79                         break;
  80
  81                 case LAPB_SABME:
  82 #if LAPB_DEBUG > 1
  83                         printk(KERN_DEBUG "lapb: (%p) S0 RX SABME(%d)\n",
  84                                lapb->dev, frame->pf);
  85 #endif
  86                         if (lapb->mode & LAPB_EXTENDED) {
  87 #if LAPB_DEBUG > 1
  88                                 printk(KERN_DEBUG "lapb: (%p) S0 TX UA(%d)\n",
  89                                        lapb->dev, frame->pf);
  90 #endif
  91 #if LAPB_DEBUG > 0
  92                                 printk(KERN_DEBUG "lapb: (%p) S0 -> S3\n",
  93                                        lapb->dev);
  94 #endif
  95                                 lapb_send_control(lapb, LAPB_UA, frame->pf,
  96                                                   LAPB_RESPONSE);
  97                                 lapb_stop_t1timer(lapb);
  98                                 lapb_stop_t2timer(lapb);
  99                                 lapb->state     = LAPB_STATE_3;
 100                                 lapb->condition = 0x00;
 101                                 lapb->n2count   = 0;
 102                                 lapb->vs        = 0;
 103                                 lapb->vr        = 0;
 104                                 lapb->va        = 0;
 105                                 lapb_connect_indication(lapb, LAPB_OK);
 106                         } else {
 107 #if LAPB_DEBUG > 1
 108                                 printk(KERN_DEBUG "lapb: (%p) S0 TX DM(%d)\n",
 109                                        lapb->dev, frame->pf);
 110 #endif
 111                                 lapb_send_control(lapb, LAPB_DM, frame->pf,
 112                                                   LAPB_RESPONSE);
 113                         }
 114                         break;
 115
 116                 case LAPB_DISC:
 117 #if LAPB_DEBUG > 1
 118                         printk(KERN_DEBUG "lapb: (%p) S0 RX DISC(%d)\n",
 119                                lapb->dev, frame->pf);
 120                         printk(KERN_DEBUG "lapb: (%p) S0 TX UA(%d)\n",
 121                                lapb->dev, frame->pf);
 122 #endif
 123                         lapb_send_control(lapb, LAPB_UA, frame->pf,
 124                                           LAPB_RESPONSE);
 125                         break;
 126
 127                 default:
 128                         break;
 129         }
 130
 131         kfree_skb(skb);
 132 }
 133
 134 /*
 135  *      State machine for state 1, Awaiting Connection State.
 136  *      The handling of the timer(s) is in file lapb_timer.c.
 137  */
 138 static void lapb_state1_machine(struct lapb_cb *lapb, struct sk_buff *skb,
 139                                 struct lapb_frame *frame)
 140 {
 141         switch (frame->type) {
 142                 case LAPB_SABM:
 143 #if LAPB_DEBUG > 1
 144                         printk(KERN_DEBUG "lapb: (%p) S1 RX SABM(%d)\n",
 145                                lapb->dev, frame->pf);
 146 #endif
 147                         if (lapb->mode & LAPB_EXTENDED) {
 148 #if LAPB_DEBUG > 1
 149                                 printk(KERN_DEBUG "lapb: (%p) S1 TX DM(%d)\n",
 150                                        lapb->dev, frame->pf);
 151 #endif
 152                                 lapb_send_control(lapb, LAPB_DM, frame->pf,
 153                                                   LAPB_RESPONSE);
 154                         } else {
 155 #if LAPB_DEBUG > 1
 156                                 printk(KERN_DEBUG "lapb: (%p) S1 TX UA(%d)\n",
 157                                        lapb->dev, frame->pf);
 158 #endif
 159                                 lapb_send_control(lapb, LAPB_UA, frame->pf,
 160                                                   LAPB_RESPONSE);
 161                         }
 162                         break;
 163
 164                 case LAPB_SABME:
 165 #if LAPB_DEBUG > 1
 166                         printk(KERN_DEBUG "lapb: (%p) S1 RX SABME(%d)\n",
 167                                lapb->dev, frame->pf);
 168 #endif
 169                         if (lapb->mode & LAPB_EXTENDED) {
 170 #if LAPB_DEBUG > 1
 171                                 printk(KERN_DEBUG "lapb: (%p) S1 TX UA(%d)\n",
 172                                        lapb->dev, frame->pf);
 173 #endif
 174                                 lapb_send_control(lapb, LAPB_UA, frame->pf,
 175                                                   LAPB_RESPONSE);
 176                         } else {
 177 #if LAPB_DEBUG > 1
 178                                 printk(KERN_DEBUG "lapb: (%p) S1 TX DM(%d)\n",
 179                                        lapb->dev, frame->pf);
 180 #endif
 181                                 lapb_send_control(lapb, LAPB_DM, frame->pf,
 182                                                   LAPB_RESPONSE);
 183                         }
 184                         break;
 185
 186                 case LAPB_DISC:
 187 #if LAPB_DEBUG > 1
 188                         printk(KERN_DEBUG "lapb: (%p) S1 RX DISC(%d)\n",
 189                                lapb->dev, frame->pf);
 190                         printk(KERN_DEBUG "lapb: (%p) S1 TX DM(%d)\n",
 191                                lapb->dev, frame->pf);
 192 #endif
 193                         lapb_send_control(lapb, LAPB_DM, frame->pf,
 194                                           LAPB_RESPONSE);
 195                         break;
 196
 197                 case LAPB_UA:
 198 #if LAPB_DEBUG > 1
 199                         printk(KERN_DEBUG "lapb: (%p) S1 RX UA(%d)\n",
 200                                lapb->dev, frame->pf);
 201 #endif
 202                         if (frame->pf) {
 203 #if LAPB_DEBUG > 0
 204                                 printk(KERN_DEBUG "lapb: (%p) S1 -> S3\n",
 205                                        lapb->dev);
 206 #endif
 207                                 lapb_stop_t1timer(lapb);
 208                                 lapb_stop_t2timer(lapb);
 209                                 lapb->state     = LAPB_STATE_3;
 210                                 lapb->condition = 0x00;
 211                                 lapb->n2count   = 0;
 212                                 lapb->vs        = 0;
 213                                 lapb->vr        = 0;
 214                                 lapb->va        = 0;
 215                                 lapb_connect_confirmation(lapb, LAPB_OK);
 216                         }
 217                         break;
 218
 219                 case LAPB_DM:
 220 #if LAPB_DEBUG > 1
 221                         printk(KERN_DEBUG "lapb: (%p) S1 RX DM(%d)\n",
 222                                lapb->dev, frame->pf);
 223 #endif
 224                         if (frame->pf) {
 225 #if LAPB_DEBUG > 0
 226                                 printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n",
 227                                        lapb->dev);
 228 #endif
 229                                 lapb_clear_queues(lapb);
 230                                 lapb->state = LAPB_STATE_0;
 231                                 lapb_start_t1timer(lapb);
 232                                 lapb_stop_t2timer(lapb);
 233                                 lapb_disconnect_indication(lapb, LAPB_REFUSED);
 234                         }
 235                         break;
 236         }
 237
 238         kfree_skb(skb);
 239 }
 240
 241 /*
 242  *      State machine for state 2, Awaiting Release State.
 243  *      The handling of the timer(s) is in file lapb_timer.c
 244  */
 245 static void lapb_state2_machine(struct lapb_cb *lapb, struct sk_buff *skb,
 246                                 struct lapb_frame *frame)
 247 {
 248         switch (frame->type) {
 249                 case LAPB_SABM:
 250                 case LAPB_SABME:
 251 #if LAPB_DEBUG > 1
 252                         printk(KERN_DEBUG "lapb: (%p) S2 RX {SABM,SABME}(%d)\n",
 253                                lapb->dev, frame->pf);
 254                         printk(KERN_DEBUG "lapb: (%p) S2 TX DM(%d)\n",
 255                                lapb->dev, frame->pf);
 256 #endif
 257                         lapb_send_control(lapb, LAPB_DM, frame->pf,
 258                                           LAPB_RESPONSE);
 259                         break;
 260
 261                 case LAPB_DISC:
 262 #if LAPB_DEBUG > 1
 263                         printk(KERN_DEBUG "lapb: (%p) S2 RX DISC(%d)\n",
 264                                lapb->dev, frame->pf);
 265                         printk(KERN_DEBUG "lapb: (%p) S2 TX UA(%d)\n",
 266                                lapb->dev, frame->pf);
 267 #endif
 268                         lapb_send_control(lapb, LAPB_UA, frame->pf,
 269                                           LAPB_RESPONSE);
 270                         break;
 271
 272                 case LAPB_UA:
 273 #if LAPB_DEBUG > 1
 274                         printk(KERN_DEBUG "lapb: (%p) S2 RX UA(%d)\n",
 275                                lapb->dev, frame->pf);
 276 #endif
 277                         if (frame->pf) {
 278 #if LAPB_DEBUG > 0
 279                                 printk(KERN_DEBUG "lapb: (%p) S2 -> S0\n",
 280                                        lapb->dev);
 281 #endif
 282                                 lapb->state = LAPB_STATE_0;
 283                                 lapb_start_t1timer(lapb);
 284                                 lapb_stop_t2timer(lapb);
 285                                 lapb_disconnect_confirmation(lapb, LAPB_OK);
 286                         }
 287                         break;
 288
 289                 case LAPB_DM:
 290 #if LAPB_DEBUG > 1
 291                         printk(KERN_DEBUG "lapb: (%p) S2 RX DM(%d)\n",
 292                                lapb->dev, frame->pf);
 293 #endif
 294                         if (frame->pf) {
 295 #if LAPB_DEBUG > 0
 296                                 printk(KERN_DEBUG "lapb: (%p) S2 -> S0\n",
 297                                        lapb->dev);
 298 #endif
 299                                 lapb->state = LAPB_STATE_0;
 300                                 lapb_start_t1timer(lapb);
 301                                 lapb_stop_t2timer(lapb);
 302                                 lapb_disconnect_confirmation(lapb,
 303                                                              LAPB_NOTCONNECTED);
 304                         }
 305                         break;
 306
 307                 case LAPB_I:
 308                 case LAPB_REJ:
 309                 case LAPB_RNR:
 310                 case LAPB_RR:
 311 #if LAPB_DEBUG > 1
 312                         printk(KERN_DEBUG "lapb: (%p) S2 RX {I,REJ,RNR,RR}"
 313                                "(%d)\n", lapb->dev, frame->pf);
 314                         printk(KERN_DEBUG "lapb: (%p) S2 RX DM(%d)\n",
 315                                lapb->dev, frame->pf);
 316 #endif
 317                         if (frame->pf)
 318                                 lapb_send_control(lapb, LAPB_DM, frame->pf,
 319                                                   LAPB_RESPONSE);
 320                         break;
 321         }
 322
 323         kfree_skb(skb);
 324 }
 325
 326 /*
 327  *      State machine for state 3, Connected State.
 328  *      The handling of the timer(s) is in file lapb_timer.c
 329  */
 330 static void lapb_state3_machine(struct lapb_cb *lapb, struct sk_buff *skb,
 331                                 struct lapb_frame *frame)
 332 {
 333         int queued = 0;
 334         int modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS :
 335                                                      LAPB_SMODULUS;
 336
 337         switch (frame->type) {
 338                 case LAPB_SABM:
 339 #if LAPB_DEBUG > 1
 340                         printk(KERN_DEBUG "lapb: (%p) S3 RX SABM(%d)\n",
 341                                lapb->dev, frame->pf);
 342 #endif
 343                         if (lapb->mode & LAPB_EXTENDED) {
 344 #if LAPB_DEBUG > 1
 345                                 printk(KERN_DEBUG "lapb: (%p) S3 TX DM(%d)\n",
 346                                        lapb->dev, frame->pf);
 347 #endif
 348                                 lapb_send_control(lapb, LAPB_DM, frame->pf,
 349                                                   LAPB_RESPONSE);
 350                         } else {
 351 #if LAPB_DEBUG > 1
 352                                 printk(KERN_DEBUG "lapb: (%p) S3 TX UA(%d)\n",
 353                                        lapb->dev, frame->pf);
 354 #endif
 355                                 lapb_send_control(lapb, LAPB_UA, frame->pf,
 356                                                   LAPB_RESPONSE);
 357                                 lapb_stop_t1timer(lapb);
 358                                 lapb_stop_t2timer(lapb);
 359                                 lapb->condition = 0x00;
 360                                 lapb->n2count   = 0;
 361                                 lapb->vs        = 0;
 362                                 lapb->vr        = 0;
 363                                 lapb->va        = 0;
 364                                 lapb_requeue_frames(lapb);
 365                         }
 366                         break;
 367
 368                 case LAPB_SABME:
 369 #if LAPB_DEBUG > 1
 370                         printk(KERN_DEBUG "lapb: (%p) S3 RX SABME(%d)\n",
 371                                lapb->dev, frame->pf);
 372 #endif
 373                         if (lapb->mode & LAPB_EXTENDED) {
 374 #if LAPB_DEBUG > 1
 375                                 printk(KERN_DEBUG "lapb: (%p) S3 TX UA(%d)\n",
 376                                        lapb->dev, frame->pf);
 377 #endif
 378                                 lapb_send_control(lapb, LAPB_UA, frame->pf,
 379                                                   LAPB_RESPONSE);
 380                                 lapb_stop_t1timer(lapb);
 381                                 lapb_stop_t2timer(lapb);
 382                                 lapb->condition = 0x00;
 383                                 lapb->n2count   = 0;
 384                                 lapb->vs        = 0;
 385                                 lapb->vr        = 0;
 386                                 lapb->va        = 0;
 387                                 lapb_requeue_frames(lapb);
 388                         } else {
 389 #if LAPB_DEBUG > 1
 390                                 printk(KERN_DEBUG "lapb: (%p) S3 TX DM(%d)\n",
 391                                        lapb->dev, frame->pf);
 392 #endif
 393                                 lapb_send_control(lapb, LAPB_DM, frame->pf,
 394                                                   LAPB_RESPONSE);
 395                         }
 396                         break;
 397
 398                 case LAPB_DISC:
 399 #if LAPB_DEBUG > 1
 400                         printk(KERN_DEBUG "lapb: (%p) S3 RX DISC(%d)\n",
 401                                lapb->dev, frame->pf);
 402 #endif
 403 #if LAPB_DEBUG > 0
 404                         printk(KERN_DEBUG "lapb: (%p) S3 -> S0\n",
 405                                lapb->dev);
 406 #endif
 407                         lapb_clear_queues(lapb);
 408                         lapb_send_control(lapb, LAPB_UA, frame->pf,
 409                                           LAPB_RESPONSE);
 410                         lapb_start_t1timer(lapb);
 411                         lapb_stop_t2timer(lapb);
 412                         lapb->state = LAPB_STATE_0;
 413                         lapb_disconnect_indication(lapb, LAPB_OK);
 414                         break;
 415
 416                 case LAPB_DM:
 417 #if LAPB_DEBUG > 1
 418                         printk(KERN_DEBUG "lapb: (%p) S3 RX DM(%d)\n",
 419                                lapb->dev, frame->pf);
 420 #endif
 421 #if LAPB_DEBUG > 0
 422                         printk(KERN_DEBUG "lapb: (%p) S3 -> S0\n",
 423                                lapb->dev);
 424 #endif
 425                         lapb_clear_queues(lapb);
 426                         lapb->state = LAPB_STATE_0;
 427                         lapb_start_t1timer(lapb);
 428                         lapb_stop_t2timer(lapb);
 429                         lapb_disconnect_indication(lapb, LAPB_NOTCONNECTED);
 430                         break;
 431
 432                 case LAPB_RNR:
 433 #if LAPB_DEBUG > 1
 434                         printk(KERN_DEBUG "lapb: (%p) S3 RX RNR(%d) R%d\n",
 435                                lapb->dev, frame->pf, frame->nr);
 436 #endif
 437                         lapb->condition |= LAPB_PEER_RX_BUSY_CONDITION;
 438                         lapb_check_need_response(lapb, frame->cr, frame->pf);
 439                         if (lapb_validate_nr(lapb, frame->nr)) {
 440                                 lapb_check_iframes_acked(lapb, frame->nr);
 441                         } else {
 442                                 lapb->frmr_data = *frame;
 443                                 lapb->frmr_type = LAPB_FRMR_Z;
 444                                 lapb_transmit_frmr(lapb);
 445 #if LAPB_DEBUG > 0
 446                                 printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n",
 447                                        lapb->dev);
 448 #endif
 449                                 lapb_start_t1timer(lapb);
 450                                 lapb_stop_t2timer(lapb);
 451                                 lapb->state   = LAPB_STATE_4;
 452                                 lapb->n2count = 0;
 453                         }
 454                         break;
 455
 456                 case LAPB_RR:
 457 #if LAPB_DEBUG > 1
 458                         printk(KERN_DEBUG "lapb: (%p) S3 RX RR(%d) R%d\n",
 459                                lapb->dev, frame->pf, frame->nr);
 460 #endif
 461                         lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
 462                         lapb_check_need_response(lapb, frame->cr, frame->pf);
 463                         if (lapb_validate_nr(lapb, frame->nr)) {
 464                                 lapb_check_iframes_acked(lapb, frame->nr);
 465                         } else {
 466                                 lapb->frmr_data = *frame;
 467                                 lapb->frmr_type = LAPB_FRMR_Z;
 468                                 lapb_transmit_frmr(lapb);
 469 #if LAPB_DEBUG > 0
 470                                 printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n",
 471                                        lapb->dev);
 472 #endif
 473                                 lapb_start_t1timer(lapb);
 474                                 lapb_stop_t2timer(lapb);
 475                                 lapb->state   = LAPB_STATE_4;
 476                                 lapb->n2count = 0;
 477                         }
 478                         break;
 479
 480                 case LAPB_REJ:
 481 #if LAPB_DEBUG > 1
 482                         printk(KERN_DEBUG "lapb: (%p) S3 RX REJ(%d) R%d\n",
 483                                lapb->dev, frame->pf, frame->nr);
 484 #endif
 485                         lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
 486                         lapb_check_need_response(lapb, frame->cr, frame->pf);
 487                         if (lapb_validate_nr(lapb, frame->nr)) {
 488                                 lapb_frames_acked(lapb, frame->nr);
 489                                 lapb_stop_t1timer(lapb);
 490                                 lapb->n2count = 0;
 491                                 lapb_requeue_frames(lapb);
 492                         } else {
 493                                 lapb->frmr_data = *frame;
 494                                 lapb->frmr_type = LAPB_FRMR_Z;
 495                                 lapb_transmit_frmr(lapb);
 496 #if LAPB_DEBUG > 0
 497                                 printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n",
 498                                        lapb->dev);
 499 #endif
 500                                 lapb_start_t1timer(lapb);
 501                                 lapb_stop_t2timer(lapb);
 502                                 lapb->state   = LAPB_STATE_4;
 503                                 lapb->n2count = 0;
 504                         }
 505                         break;
 506
 507                 case LAPB_I:
 508 #if LAPB_DEBUG > 1
 509                         printk(KERN_DEBUG "lapb: (%p) S3 RX I(%d) S%d R%d\n",
 510                                lapb->dev, frame->pf, frame->ns, frame->nr);
 511 #endif
 512                         if (!lapb_validate_nr(lapb, frame->nr)) {
 513                                 lapb->frmr_data = *frame;
 514                                 lapb->frmr_type = LAPB_FRMR_Z;
 515                                 lapb_transmit_frmr(lapb);
 516 #if LAPB_DEBUG > 0
 517                                 printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n",
 518                                        lapb->dev);
 519 #endif
 520                                 lapb_start_t1timer(lapb);
 521                                 lapb_stop_t2timer(lapb);
 522                                 lapb->state   = LAPB_STATE_4;
 523                                 lapb->n2count = 0;
 524                                 break;
 525                         }
 526                         if (lapb->condition & LAPB_PEER_RX_BUSY_CONDITION)
 527                                 lapb_frames_acked(lapb, frame->nr);
 528                         else
 529                                 lapb_check_iframes_acked(lapb, frame->nr);
 530
 531                         if (frame->ns == lapb->vr) {
 532                                 int cn;
 533                                 cn = lapb_data_indication(lapb, skb);
 534                                 queued = 1;
 535                                 /*
 536                                  * If upper layer has dropped the frame, we
 537                                  * basically ignore any further protocol
 538                                  * processing. This will cause the peer
 539                                  * to re-transmit the frame later like
 540                                  * a frame lost on the wire.
 541                                  */
 542                                 if (cn == NET_RX_DROP) {
 543                                         printk(KERN_DEBUG
 544                                                "LAPB: rx congestion\n");
 545                                         break;
 546                                 }
 547                                 lapb->vr = (lapb->vr + 1) % modulus;
 548                                 lapb->condition &= ~LAPB_REJECT_CONDITION;
 549                                 if (frame->pf)
 550                                         lapb_enquiry_response(lapb);
 551                                 else {
 552                                         if (!(lapb->condition &
 553                                               LAPB_ACK_PENDING_CONDITION)) {
 554                                                 lapb->condition |= LAPB_ACK_PENDING_CONDITION;
 555                                                 lapb_start_t2timer(lapb);
 556                                         }
 557                                 }
 558                         } else {
 559                                 if (lapb->condition & LAPB_REJECT_CONDITION) {
 560                                         if (frame->pf)
 561                                                 lapb_enquiry_response(lapb);
 562                                 } else {
 563 #if LAPB_DEBUG > 1
 564                                         printk(KERN_DEBUG
 565                                                "lapb: (%p) S3 TX REJ(%d) R%d\n",
 566                                                lapb->dev, frame->pf, lapb->vr);
 567 #endif
 568                                         lapb->condition |= LAPB_REJECT_CONDITION;
 569                                         lapb_send_control(lapb, LAPB_REJ,
 570                                                           frame->pf,
 571                                                           LAPB_RESPONSE);
 572                                         lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
 573                                 }
 574                         }
 575                         break;
 576
 577                 case LAPB_FRMR:
 578 #if LAPB_DEBUG > 1
 579                         printk(KERN_DEBUG "lapb: (%p) S3 RX FRMR(%d) %02X "
 580                                "%02X %02X %02X %02X\n", lapb->dev, frame->pf,
 581                                skb->data[0], skb->data[1], skb->data[2],
 582                                skb->data[3], skb->data[4]);
 583 #endif
 584                         lapb_establish_data_link(lapb);
 585 #if LAPB_DEBUG > 0
 586                         printk(KERN_DEBUG "lapb: (%p) S3 -> S1\n",
 587                                lapb->dev);
 588 #endif
 589                         lapb_requeue_frames(lapb);
 590                         lapb->state = LAPB_STATE_1;
 591                         break;
 592
 593                 case LAPB_ILLEGAL:
 594 #if LAPB_DEBUG > 1
 595                         printk(KERN_DEBUG "lapb: (%p) S3 RX ILLEGAL(%d)\n",
 596                                lapb->dev, frame->pf);
 597 #endif
 598                         lapb->frmr_data = *frame;
 599                         lapb->frmr_type = LAPB_FRMR_W;
 600                         lapb_transmit_frmr(lapb);
 601 #if LAPB_DEBUG > 0
 602                         printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n", lapb->dev);
 603 #endif
 604                         lapb_start_t1timer(lapb);
 605                         lapb_stop_t2timer(lapb);
 606                         lapb->state   = LAPB_STATE_4;
 607                         lapb->n2count = 0;
 608                         break;
 609         }
 610
 611         if (!queued)
 612                 kfree_skb(skb);
 613 }
 614
 615 /*
 616  *      State machine for state 4, Frame Reject State.
 617  *      The handling of the timer(s) is in file lapb_timer.c.
 618  */
 619 static void lapb_state4_machine(struct lapb_cb *lapb, struct sk_buff *skb,
 620                                 struct lapb_frame *frame)
 621 {
 622         switch (frame->type) {
 623                 case LAPB_SABM:
 624 #if LAPB_DEBUG > 1
 625                         printk(KERN_DEBUG "lapb: (%p) S4 RX SABM(%d)\n",
 626                                lapb->dev, frame->pf);
 627 #endif
 628                         if (lapb->mode & LAPB_EXTENDED) {
 629 #if LAPB_DEBUG > 1
 630                                 printk(KERN_DEBUG "lapb: (%p) S4 TX DM(%d)\n",
 631                                        lapb->dev, frame->pf);
 632 #endif
 633                                 lapb_send_control(lapb, LAPB_DM, frame->pf,
 634                                                   LAPB_RESPONSE);
 635                         } else {
 636 #if LAPB_DEBUG > 1
 637                                 printk(KERN_DEBUG "lapb: (%p) S4 TX UA(%d)\n",
 638                                        lapb->dev, frame->pf);
 639 #endif
 640 #if LAPB_DEBUG > 0
 641                                 printk(KERN_DEBUG "lapb: (%p) S4 -> S3\n",
 642                                        lapb->dev);
 643 #endif
 644                                 lapb_send_control(lapb, LAPB_UA, frame->pf,
 645                                                   LAPB_RESPONSE);
 646                                 lapb_stop_t1timer(lapb);
 647                                 lapb_stop_t2timer(lapb);
 648                                 lapb->state     = LAPB_STATE_3;
 649                                 lapb->condition = 0x00;
 650                                 lapb->n2count   = 0;
 651                                 lapb->vs        = 0;
 652                                 lapb->vr        = 0;
 653                                 lapb->va        = 0;
 654                                 lapb_connect_indication(lapb, LAPB_OK);
 655                         }
 656                         break;
 657
 658                 case LAPB_SABME:
 659 #if LAPB_DEBUG > 1
 660                         printk(KERN_DEBUG "lapb: (%p) S4 RX SABME(%d)\n",
 661                                lapb->dev, frame->pf);
 662 #endif
 663                         if (lapb->mode & LAPB_EXTENDED) {
 664 #if LAPB_DEBUG > 1
 665                                 printk(KERN_DEBUG "lapb: (%p) S4 TX UA(%d)\n",
 666                                        lapb->dev, frame->pf);
 667 #endif
 668 #if LAPB_DEBUG > 0
 669                                 printk(KERN_DEBUG "lapb: (%p) S4 -> S3\n",
 670                                        lapb->dev);
 671 #endif
 672                                 lapb_send_control(lapb, LAPB_UA, frame->pf,
 673                                                   LAPB_RESPONSE);
 674                                 lapb_stop_t1timer(lapb);
 675                                 lapb_stop_t2timer(lapb);
 676                                 lapb->state     = LAPB_STATE_3;
 677                                 lapb->condition = 0x00;
 678                                 lapb->n2count   = 0;
 679                                 lapb->vs        = 0;
 680                                 lapb->vr        = 0;
 681                                 lapb->va        = 0;
 682                                 lapb_connect_indication(lapb, LAPB_OK);
 683                         } else {
 684 #if LAPB_DEBUG > 1
 685                                 printk(KERN_DEBUG "lapb: (%p) S4 TX DM(%d)\n",
 686                                        lapb->dev, frame->pf);
 687 #endif
 688                                 lapb_send_control(lapb, LAPB_DM, frame->pf,
 689                                                   LAPB_RESPONSE);
 690                         }
 691                         break;
 692         }
 693
 694         kfree_skb(skb);
 695 }
 696
 697 /*
 698  *      Process an incoming LAPB frame
 699  */
 700 void lapb_data_input(struct lapb_cb *lapb, struct sk_buff *skb)
 701 {
 702         struct lapb_frame frame;
 703
 704         if (lapb_decode(lapb, skb, &frame) < 0) {
 705                 kfree_skb(skb);
 706                 return;
 707         }
 708
 709         switch (lapb->state) {
 710         case LAPB_STATE_0:
 711                 lapb_state0_machine(lapb, skb, &frame); break;
 712         case LAPB_STATE_1:
 713                 lapb_state1_machine(lapb, skb, &frame); break;
 714         case LAPB_STATE_2:
 715                 lapb_state2_machine(lapb, skb, &frame); break;
 716         case LAPB_STATE_3:
 717                 lapb_state3_machine(lapb, skb, &frame); break;
 718         case LAPB_STATE_4:
 719                 lapb_state4_machine(lapb, skb, &frame); break;
 720         }
 721
 722         lapb_kick(lapb);
 723 }