net/irda/irlap_frame.c

   1 /*********************************************************************
   2  *
   3  * Filename:      irlap_frame.c
   4  * Version:       1.0
   5  * Description:   Build and transmit IrLAP frames
   6  * Status:        Stable
   7  * Author:        Dag Brattli <dagb@cs.uit.no>
   8  * Created at:    Tue Aug 19 10:27:26 1997
   9  * Modified at:   Wed Jan  5 08:59:04 2000
  10  * Modified by:   Dag Brattli <dagb@cs.uit.no>
  11  *
  12  *     Copyright (c) 1998-2000 Dag Brattli <dagb@cs.uit.no>,
  13  *     All Rights Reserved.
  14  *     Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
  15  *
  16  *     This program is free software; you can redistribute it and/or
  17  *     modify it under the terms of the GNU General Public License as
  18  *     published by the Free Software Foundation; either version 2 of
  19  *     the License, or (at your option) any later version.
  20  *
  21  *     Neither Dag Brattli nor University of Tromsø admit liability nor
  22  *     provide warranty for any of this software. This material is
  23  *     provided "AS-IS" and at no charge.
  24  *
  25  ********************************************************************/
  26
  27 #include <linux/skbuff.h>
  28 #include <linux/if.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/irda.h>
  32 #include <linux/slab.h>
  33
  34 #include <net/pkt_sched.h>
  35 #include <net/sock.h>
  36
  37 #include <asm/byteorder.h>
  38
  39 #include <net/irda/irda.h>
  40 #include <net/irda/irda_device.h>
  41 #include <net/irda/irlap.h>
  42 #include <net/irda/wrapper.h>
  43 #include <net/irda/timer.h>
  44 #include <net/irda/irlap_frame.h>
  45 #include <net/irda/qos.h>
  46
  47 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
  48                                int command);
  49
  50 /*
  51  * Function irlap_insert_info (self, skb)
  52  *
  53  *    Insert minimum turnaround time and speed information into the skb. We
  54  *    need to do this since it's per packet relevant information. Safe to
  55  *    have this function inlined since it's only called from one place
  56  */
  57 static inline void irlap_insert_info(struct irlap_cb *self,
  58                                      struct sk_buff *skb)
  59 {
  60         struct irda_skb_cb *cb = (struct irda_skb_cb *) skb->cb;
  61
  62         /*
  63          * Insert MTT (min. turn time) and speed into skb, so that the
  64          * device driver knows which settings to use
  65          */
  66         cb->magic = LAP_MAGIC;
  67         cb->mtt = self->mtt_required;
  68         cb->next_speed = self->speed;
  69
  70         /* Reset */
  71         self->mtt_required = 0;
  72
  73         /*
  74          * Delay equals negotiated BOFs count, plus the number of BOFs to
  75          * force the negotiated minimum turnaround time
  76          */
  77         cb->xbofs = self->bofs_count;
  78         cb->next_xbofs = self->next_bofs;
  79         cb->xbofs_delay = self->xbofs_delay;
  80
  81         /* Reset XBOF's delay (used only for getting min turn time) */
  82         self->xbofs_delay = 0;
  83         /* Put the correct xbofs value for the next packet */
  84         self->bofs_count = self->next_bofs;
  85 }
  86
  87 /*
  88  * Function irlap_queue_xmit (self, skb)
  89  *
  90  *    A little wrapper for dev_queue_xmit, so we can insert some common
  91  *    code into it.
  92  */
  93 void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb)
  94 {
  95         /* Some common init stuff */
  96         skb->dev = self->netdev;
  97         skb_reset_mac_header(skb);
  98         skb_reset_network_header(skb);
  99         skb_reset_transport_header(skb);
 100         skb->protocol = htons(ETH_P_IRDA);
 101         skb->priority = TC_PRIO_BESTEFFORT;
 102
 103         irlap_insert_info(self, skb);
 104
 105         if (unlikely(self->mode & IRDA_MODE_MONITOR)) {
 106                 IRDA_DEBUG(3, "%s(): %s is in monitor mode\n", __func__,
 107                            self->netdev->name);
 108                 dev_kfree_skb(skb);
 109                 return;
 110         }
 111
 112         dev_queue_xmit(skb);
 113 }
 114
 115 /*
 116  * Function irlap_send_snrm_cmd (void)
 117  *
 118  *    Transmits a connect SNRM command frame
 119  */
 120 void irlap_send_snrm_frame(struct irlap_cb *self, struct qos_info *qos)
 121 {
 122         struct sk_buff *tx_skb;
 123         struct snrm_frame *frame;
 124         int ret;
 125
 126         IRDA_ASSERT(self != NULL, return;);
 127         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 128
 129         /* Allocate frame */
 130         tx_skb = alloc_skb(sizeof(struct snrm_frame) +
 131                            IRLAP_NEGOCIATION_PARAMS_LEN,
 132                            GFP_ATOMIC);
 133         if (!tx_skb)
 134                 return;
 135
 136         frame = (struct snrm_frame *) skb_put(tx_skb, 2);
 137
 138         /* Insert connection address field */
 139         if (qos)
 140                 frame->caddr = CMD_FRAME | CBROADCAST;
 141         else
 142                 frame->caddr = CMD_FRAME | self->caddr;
 143
 144         /* Insert control field */
 145         frame->control = SNRM_CMD | PF_BIT;
 146
 147         /*
 148          *  If we are establishing a connection then insert QoS parameters
 149          */
 150         if (qos) {
 151                 skb_put(tx_skb, 9); /* 25 left */
 152                 frame->saddr = cpu_to_le32(self->saddr);
 153                 frame->daddr = cpu_to_le32(self->daddr);
 154
 155                 frame->ncaddr = self->caddr;
 156
 157                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 158                 if (ret < 0) {
 159                         dev_kfree_skb(tx_skb);
 160                         return;
 161                 }
 162         }
 163         irlap_queue_xmit(self, tx_skb);
 164 }
 165
 166 /*
 167  * Function irlap_recv_snrm_cmd (skb, info)
 168  *
 169  *    Received SNRM (Set Normal Response Mode) command frame
 170  *
 171  */
 172 static void irlap_recv_snrm_cmd(struct irlap_cb *self, struct sk_buff *skb,
 173                                 struct irlap_info *info)
 174 {
 175         struct snrm_frame *frame;
 176
 177         if (pskb_may_pull(skb,sizeof(struct snrm_frame))) {
 178                 frame = (struct snrm_frame *) skb->data;
 179
 180                 /* Copy the new connection address ignoring the C/R bit */
 181                 info->caddr = frame->ncaddr & 0xFE;
 182
 183                 /* Check if the new connection address is valid */
 184                 if ((info->caddr == 0x00) || (info->caddr == 0xfe)) {
 185                         IRDA_DEBUG(3, "%s(), invalid connection address!\n",
 186                                    __func__);
 187                         return;
 188                 }
 189
 190                 /* Copy peer device address */
 191                 info->daddr = le32_to_cpu(frame->saddr);
 192                 info->saddr = le32_to_cpu(frame->daddr);
 193
 194                 /* Only accept if addressed directly to us */
 195                 if (info->saddr != self->saddr) {
 196                         IRDA_DEBUG(2, "%s(), not addressed to us!\n",
 197                                    __func__);
 198                         return;
 199                 }
 200                 irlap_do_event(self, RECV_SNRM_CMD, skb, info);
 201         } else {
 202                 /* Signal that this SNRM frame does not contain and I-field */
 203                 irlap_do_event(self, RECV_SNRM_CMD, skb, NULL);
 204         }
 205 }
 206
 207 /*
 208  * Function irlap_send_ua_response_frame (qos)
 209  *
 210  *    Send UA (Unnumbered Acknowledgement) frame
 211  *
 212  */
 213 void irlap_send_ua_response_frame(struct irlap_cb *self, struct qos_info *qos)
 214 {
 215         struct sk_buff *tx_skb;
 216         struct ua_frame *frame;
 217         int ret;
 218
 219         IRDA_DEBUG(2, "%s() <%ld>\n", __func__, jiffies);
 220
 221         IRDA_ASSERT(self != NULL, return;);
 222         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 223
 224         /* Allocate frame */
 225         tx_skb = alloc_skb(sizeof(struct ua_frame) +
 226                            IRLAP_NEGOCIATION_PARAMS_LEN,
 227                            GFP_ATOMIC);
 228         if (!tx_skb)
 229                 return;
 230
 231         frame = (struct ua_frame *) skb_put(tx_skb, 10);
 232
 233         /* Build UA response */
 234         frame->caddr = self->caddr;
 235         frame->control = UA_RSP | PF_BIT;
 236
 237         frame->saddr = cpu_to_le32(self->saddr);
 238         frame->daddr = cpu_to_le32(self->daddr);
 239
 240         /* Should we send QoS negotiation parameters? */
 241         if (qos) {
 242                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 243                 if (ret < 0) {
 244                         dev_kfree_skb(tx_skb);
 245                         return;
 246                 }
 247         }
 248
 249         irlap_queue_xmit(self, tx_skb);
 250 }
 251
 252
 253 /*
 254  * Function irlap_send_dm_frame (void)
 255  *
 256  *    Send disconnected mode (DM) frame
 257  *
 258  */
 259 void irlap_send_dm_frame( struct irlap_cb *self)
 260 {
 261         struct sk_buff *tx_skb = NULL;
 262         struct dm_frame *frame;
 263
 264         IRDA_ASSERT(self != NULL, return;);
 265         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 266
 267         tx_skb = alloc_skb(sizeof(struct dm_frame), GFP_ATOMIC);
 268         if (!tx_skb)
 269                 return;
 270
 271         frame = (struct dm_frame *)skb_put(tx_skb, 2);
 272
 273         if (self->state == LAP_NDM)
 274                 frame->caddr = CBROADCAST;
 275         else
 276                 frame->caddr = self->caddr;
 277
 278         frame->control = DM_RSP | PF_BIT;
 279
 280         irlap_queue_xmit(self, tx_skb);
 281 }
 282
 283 /*
 284  * Function irlap_send_disc_frame (void)
 285  *
 286  *    Send disconnect (DISC) frame
 287  *
 288  */
 289 void irlap_send_disc_frame(struct irlap_cb *self)
 290 {
 291         struct sk_buff *tx_skb = NULL;
 292         struct disc_frame *frame;
 293
 294         IRDA_DEBUG(3, "%s()\n", __func__);
 295
 296         IRDA_ASSERT(self != NULL, return;);
 297         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 298
 299         tx_skb = alloc_skb(sizeof(struct disc_frame), GFP_ATOMIC);
 300         if (!tx_skb)
 301                 return;
 302
 303         frame = (struct disc_frame *)skb_put(tx_skb, 2);
 304
 305         frame->caddr = self->caddr | CMD_FRAME;
 306         frame->control = DISC_CMD | PF_BIT;
 307
 308         irlap_queue_xmit(self, tx_skb);
 309 }
 310
 311 /*
 312  * Function irlap_send_discovery_xid_frame (S, s, command)
 313  *
 314  *    Build and transmit a XID (eXchange station IDentifier) discovery
 315  *    frame.
 316  */
 317 void irlap_send_discovery_xid_frame(struct irlap_cb *self, int S, __u8 s,
 318                                     __u8 command, discovery_t *discovery)
 319 {
 320         struct sk_buff *tx_skb = NULL;
 321         struct xid_frame *frame;
 322         __u32 bcast = BROADCAST;
 323         __u8 *info;
 324
 325         IRDA_DEBUG(4, "%s(), s=%d, S=%d, command=%d\n", __func__,
 326                    s, S, command);
 327
 328         IRDA_ASSERT(self != NULL, return;);
 329         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 330         IRDA_ASSERT(discovery != NULL, return;);
 331
 332         tx_skb = alloc_skb(sizeof(struct xid_frame) + IRLAP_DISCOVERY_INFO_LEN,
 333                            GFP_ATOMIC);
 334         if (!tx_skb)
 335                 return;
 336
 337         skb_put(tx_skb, 14);
 338         frame = (struct xid_frame *) tx_skb->data;
 339
 340         if (command) {
 341                 frame->caddr = CBROADCAST | CMD_FRAME;
 342                 frame->control =  XID_CMD | PF_BIT;
 343         } else {
 344                 frame->caddr = CBROADCAST;
 345                 frame->control =  XID_RSP | PF_BIT;
 346         }
 347         frame->ident = XID_FORMAT;
 348
 349         frame->saddr = cpu_to_le32(self->saddr);
 350
 351         if (command)
 352                 frame->daddr = cpu_to_le32(bcast);
 353         else
 354                 frame->daddr = cpu_to_le32(discovery->data.daddr);
 355
 356         switch (S) {
 357         case 1:
 358                 frame->flags = 0x00;
 359                 break;
 360         case 6:
 361                 frame->flags = 0x01;
 362                 break;
 363         case 8:
 364                 frame->flags = 0x02;
 365                 break;
 366         case 16:
 367                 frame->flags = 0x03;
 368                 break;
 369         default:
 370                 frame->flags = 0x02;
 371                 break;
 372         }
 373
 374         frame->slotnr = s;
 375         frame->version = 0x00;
 376
 377         /*
 378          *  Provide info for final slot only in commands, and for all
 379          *  responses. Send the second byte of the hint only if the
 380          *  EXTENSION bit is set in the first byte.
 381          */
 382         if (!command || (frame->slotnr == 0xff)) {
 383                 int len;
 384
 385                 if (discovery->data.hints[0] & HINT_EXTENSION) {
 386                         info = skb_put(tx_skb, 2);
 387                         info[0] = discovery->data.hints[0];
 388                         info[1] = discovery->data.hints[1];
 389                 } else {
 390                         info = skb_put(tx_skb, 1);
 391                         info[0] = discovery->data.hints[0];
 392                 }
 393                 info = skb_put(tx_skb, 1);
 394                 info[0] = discovery->data.charset;
 395
 396                 len = IRDA_MIN(discovery->name_len, skb_tailroom(tx_skb));
 397                 info = skb_put(tx_skb, len);
 398                 memcpy(info, discovery->data.info, len);
 399         }
 400         irlap_queue_xmit(self, tx_skb);
 401 }
 402
 403 /*
 404  * Function irlap_recv_discovery_xid_rsp (skb, info)
 405  *
 406  *    Received a XID discovery response
 407  *
 408  */
 409 static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
 410                                          struct sk_buff *skb,
 411                                          struct irlap_info *info)
 412 {
 413         struct xid_frame *xid;
 414         discovery_t *discovery = NULL;
 415         __u8 *discovery_info;
 416         char *text;
 417
 418         IRDA_DEBUG(4, "%s()\n", __func__);
 419
 420         IRDA_ASSERT(self != NULL, return;);
 421         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 422
 423         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 424                 IRDA_ERROR("%s: frame too short!\n", __func__);
 425                 return;
 426         }
 427
 428         xid = (struct xid_frame *) skb->data;
 429
 430         info->daddr = le32_to_cpu(xid->saddr);
 431         info->saddr = le32_to_cpu(xid->daddr);
 432
 433         /* Make sure frame is addressed to us */
 434         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 435                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 436                            __func__);
 437                 return;
 438         }
 439
 440         if ((discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {
 441                 IRDA_WARNING("%s: kmalloc failed!\n", __func__);
 442                 return;
 443         }
 444
 445         discovery->data.daddr = info->daddr;
 446         discovery->data.saddr = self->saddr;
 447         discovery->timestamp = jiffies;
 448
 449         IRDA_DEBUG(4, "%s(), daddr=%08x\n", __func__,
 450                    discovery->data.daddr);
 451
 452         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 453
 454         /* Get info returned from peer */
 455         discovery->data.hints[0] = discovery_info[0];
 456         if (discovery_info[0] & HINT_EXTENSION) {
 457                 IRDA_DEBUG(4, "EXTENSION\n");
 458                 discovery->data.hints[1] = discovery_info[1];
 459                 discovery->data.charset = discovery_info[2];
 460                 text = (char *) &discovery_info[3];
 461         } else {
 462                 discovery->data.hints[1] = 0;
 463                 discovery->data.charset = discovery_info[1];
 464                 text = (char *) &discovery_info[2];
 465         }
 466         /*
 467          *  Terminate info string, should be safe since this is where the
 468          *  FCS bytes resides.
 469          */
 470         skb->data[skb->len] = '\0';
 471         strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 472         discovery->name_len = strlen(discovery->data.info);
 473
 474         info->discovery = discovery;
 475
 476         irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
 477 }
 478
 479 /*
 480  * Function irlap_recv_discovery_xid_cmd (skb, info)
 481  *
 482  *    Received a XID discovery command
 483  *
 484  */
 485 static void irlap_recv_discovery_xid_cmd(struct irlap_cb *self,
 486                                          struct sk_buff *skb,
 487                                          struct irlap_info *info)
 488 {
 489         struct xid_frame *xid;
 490         discovery_t *discovery = NULL;
 491         __u8 *discovery_info;
 492         char *text;
 493
 494         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 495                 IRDA_ERROR("%s: frame too short!\n", __func__);
 496                 return;
 497         }
 498
 499         xid = (struct xid_frame *) skb->data;
 500
 501         info->daddr = le32_to_cpu(xid->saddr);
 502         info->saddr = le32_to_cpu(xid->daddr);
 503
 504         /* Make sure frame is addressed to us */
 505         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 506                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 507                            __func__);
 508                 return;
 509         }
 510
 511         switch (xid->flags & 0x03) {
 512         case 0x00:
 513                 info->S = 1;
 514                 break;
 515         case 0x01:
 516                 info->S = 6;
 517                 break;
 518         case 0x02:
 519                 info->S = 8;
 520                 break;
 521         case 0x03:
 522                 info->S = 16;
 523                 break;
 524         default:
 525                 /* Error!! */
 526                 return;
 527         }
 528         info->s = xid->slotnr;
 529
 530         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 531
 532         /*
 533          *  Check if last frame
 534          */
 535         if (info->s == 0xff) {
 536                 /* Check if things are sane at this point... */
 537                 if((discovery_info == NULL) ||
 538                    !pskb_may_pull(skb, 3)) {
 539                         IRDA_ERROR("%s: discovery frame too short!\n",
 540                                    __func__);
 541                         return;
 542                 }
 543
 544                 /*
 545                  *  We now have some discovery info to deliver!
 546                  */
 547                 discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC);
 548                 if (!discovery) {
 549                         IRDA_WARNING("%s: unable to malloc!\n", __func__);
 550                         return;
 551                 }
 552
 553                 discovery->data.daddr = info->daddr;
 554                 discovery->data.saddr = self->saddr;
 555                 discovery->timestamp = jiffies;
 556
 557                 discovery->data.hints[0] = discovery_info[0];
 558                 if (discovery_info[0] & HINT_EXTENSION) {
 559                         discovery->data.hints[1] = discovery_info[1];
 560                         discovery->data.charset = discovery_info[2];
 561                         text = (char *) &discovery_info[3];
 562                 } else {
 563                         discovery->data.hints[1] = 0;
 564                         discovery->data.charset = discovery_info[1];
 565                         text = (char *) &discovery_info[2];
 566                 }
 567                 /*
 568                  *  Terminate string, should be safe since this is where the
 569                  *  FCS bytes resides.
 570                  */
 571                 skb->data[skb->len] = '\0';
 572                 strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 573                 discovery->name_len = strlen(discovery->data.info);
 574
 575                 info->discovery = discovery;
 576         } else
 577                 info->discovery = NULL;
 578
 579         irlap_do_event(self, RECV_DISCOVERY_XID_CMD, skb, info);
 580 }
 581
 582 /*
 583  * Function irlap_send_rr_frame (self, command)
 584  *
 585  *    Build and transmit RR (Receive Ready) frame. Notice that it is currently
 586  *    only possible to send RR frames with the poll bit set.
 587  */
 588 void irlap_send_rr_frame(struct irlap_cb *self, int command)
 589 {
 590         struct sk_buff *tx_skb;
 591         struct rr_frame *frame;
 592
 593         tx_skb = alloc_skb(sizeof(struct rr_frame), GFP_ATOMIC);
 594         if (!tx_skb)
 595                 return;
 596
 597         frame = (struct rr_frame *)skb_put(tx_skb, 2);
 598
 599         frame->caddr = self->caddr;
 600         frame->caddr |= (command) ? CMD_FRAME : 0;
 601
 602         frame->control = RR | PF_BIT | (self->vr << 5);
 603
 604         irlap_queue_xmit(self, tx_skb);
 605 }
 606
 607 /*
 608  * Function irlap_send_rd_frame (self)
 609  *
 610  *    Request disconnect. Used by a secondary station to request the
 611  *    disconnection of the link.
 612  */
 613 void irlap_send_rd_frame(struct irlap_cb *self)
 614 {
 615         struct sk_buff *tx_skb;
 616         struct rd_frame *frame;
 617
 618         tx_skb = alloc_skb(sizeof(struct rd_frame), GFP_ATOMIC);
 619         if (!tx_skb)
 620                 return;
 621
 622         frame = (struct rd_frame *)skb_put(tx_skb, 2);
 623
 624         frame->caddr = self->caddr;
 625         frame->caddr = RD_RSP | PF_BIT;
 626
 627         irlap_queue_xmit(self, tx_skb);
 628 }
 629
 630 /*
 631  * Function irlap_recv_rr_frame (skb, info)
 632  *
 633  *    Received RR (Receive Ready) frame from peer station, no harm in
 634  *    making it inline since its called only from one single place
 635  *    (irlap_driver_rcv).
 636  */
 637 static inline void irlap_recv_rr_frame(struct irlap_cb *self,
 638                                        struct sk_buff *skb,
 639                                        struct irlap_info *info, int command)
 640 {
 641         info->nr = skb->data[1] >> 5;
 642
 643         /* Check if this is a command or a response frame */
 644         if (command)
 645                 irlap_do_event(self, RECV_RR_CMD, skb, info);
 646         else
 647                 irlap_do_event(self, RECV_RR_RSP, skb, info);
 648 }
 649
 650 /*
 651  * Function irlap_recv_rnr_frame (self, skb, info)
 652  *
 653  *    Received RNR (Receive Not Ready) frame from peer station
 654  *
 655  */
 656 static void irlap_recv_rnr_frame(struct irlap_cb *self, struct sk_buff *skb,
 657                                  struct irlap_info *info, int command)
 658 {
 659         info->nr = skb->data[1] >> 5;
 660
 661         IRDA_DEBUG(4, "%s(), nr=%d, %ld\n", __func__, info->nr, jiffies);
 662
 663         if (command)
 664                 irlap_do_event(self, RECV_RNR_CMD, skb, info);
 665         else
 666                 irlap_do_event(self, RECV_RNR_RSP, skb, info);
 667 }
 668
 669 static void irlap_recv_rej_frame(struct irlap_cb *self, struct sk_buff *skb,
 670                                  struct irlap_info *info, int command)
 671 {
 672         IRDA_DEBUG(0, "%s()\n", __func__);
 673
 674         info->nr = skb->data[1] >> 5;
 675
 676         /* Check if this is a command or a response frame */
 677         if (command)
 678                 irlap_do_event(self, RECV_REJ_CMD, skb, info);
 679         else
 680                 irlap_do_event(self, RECV_REJ_RSP, skb, info);
 681 }
 682
 683 static void irlap_recv_srej_frame(struct irlap_cb *self, struct sk_buff *skb,
 684                                   struct irlap_info *info, int command)
 685 {
 686         IRDA_DEBUG(0, "%s()\n", __func__);
 687
 688         info->nr = skb->data[1] >> 5;
 689
 690         /* Check if this is a command or a response frame */
 691         if (command)
 692                 irlap_do_event(self, RECV_SREJ_CMD, skb, info);
 693         else
 694                 irlap_do_event(self, RECV_SREJ_RSP, skb, info);
 695 }
 696
 697 static void irlap_recv_disc_frame(struct irlap_cb *self, struct sk_buff *skb,
 698                                   struct irlap_info *info, int command)
 699 {
 700         IRDA_DEBUG(2, "%s()\n", __func__);
 701
 702         /* Check if this is a command or a response frame */
 703         if (command)
 704                 irlap_do_event(self, RECV_DISC_CMD, skb, info);
 705         else
 706                 irlap_do_event(self, RECV_RD_RSP, skb, info);
 707 }
 708
 709 /*
 710  * Function irlap_recv_ua_frame (skb, frame)
 711  *
 712  *    Received UA (Unnumbered Acknowledgement) frame
 713  *
 714  */
 715 static inline void irlap_recv_ua_frame(struct irlap_cb *self,
 716                                        struct sk_buff *skb,
 717                                        struct irlap_info *info)
 718 {
 719         irlap_do_event(self, RECV_UA_RSP, skb, info);
 720 }
 721
 722 /*
 723  * Function irlap_send_data_primary(self, skb)
 724  *
 725  *    Send I-frames as the primary station but without the poll bit set
 726  *
 727  */
 728 void irlap_send_data_primary(struct irlap_cb *self, struct sk_buff *skb)
 729 {
 730         struct sk_buff *tx_skb;
 731
 732         if (skb->data[1] == I_FRAME) {
 733
 734                 /*
 735                  *  Insert frame sequence number (Vs) in control field before
 736                  *  inserting into transmit window queue.
 737                  */
 738                 skb->data[1] = I_FRAME | (self->vs << 1);
 739
 740                 /*
 741                  *  Insert frame in store, in case of retransmissions
 742                  *  Increase skb reference count, see irlap_do_event()
 743                  */
 744                 skb_get(skb);
 745                 skb_queue_tail(&self->wx_list, skb);
 746
 747                 /* Copy buffer */
 748                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 749                 if (tx_skb == NULL) {
 750                         return;
 751                 }
 752
 753                 self->vs = (self->vs + 1) % 8;
 754                 self->ack_required = FALSE;
 755                 self->window -= 1;
 756
 757                 irlap_send_i_frame( self, tx_skb, CMD_FRAME);
 758         } else {
 759                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __func__);
 760                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 761                 self->window -= 1;
 762         }
 763 }
 764 /*
 765  * Function irlap_send_data_primary_poll (self, skb)
 766  *
 767  *    Send I(nformation) frame as primary with poll bit set
 768  */
 769 void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
 770 {
 771         struct sk_buff *tx_skb;
 772         int transmission_time;
 773
 774         /* Stop P timer */
 775         del_timer(&self->poll_timer);
 776
 777         /* Is this reliable or unreliable data? */
 778         if (skb->data[1] == I_FRAME) {
 779
 780                 /*
 781                  *  Insert frame sequence number (Vs) in control field before
 782                  *  inserting into transmit window queue.
 783                  */
 784                 skb->data[1] = I_FRAME | (self->vs << 1);
 785
 786                 /*
 787                  *  Insert frame in store, in case of retransmissions
 788                  *  Increase skb reference count, see irlap_do_event()
 789                  */
 790                 skb_get(skb);
 791                 skb_queue_tail(&self->wx_list, skb);
 792
 793                 /* Copy buffer */
 794                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 795                 if (tx_skb == NULL) {
 796                         return;
 797                 }
 798
 799                 /*
 800                  *  Set poll bit if necessary. We do this to the copied
 801                  *  skb, since retransmitted need to set or clear the poll
 802                  *  bit depending on when they are sent.
 803                  */
 804                 tx_skb->data[1] |= PF_BIT;
 805
 806                 self->vs = (self->vs + 1) % 8;
 807                 self->ack_required = FALSE;
 808
 809                 irlap_next_state(self, LAP_NRM_P);
 810                 irlap_send_i_frame(self, tx_skb, CMD_FRAME);
 811         } else {
 812                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __func__);
 813
 814                 if (self->ack_required) {
 815                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 816                         irlap_next_state(self, LAP_NRM_P);
 817                         irlap_send_rr_frame(self, CMD_FRAME);
 818                         self->ack_required = FALSE;
 819                 } else {
 820                         skb->data[1] |= PF_BIT;
 821                         irlap_next_state(self, LAP_NRM_P);
 822                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 823                 }
 824         }
 825
 826         /* How much time we took for transmission of all frames.
 827          * We don't know, so let assume we used the full window. Jean II */
 828         transmission_time = self->final_timeout;
 829
 830         /* Reset parameter so that we can fill next window */
 831         self->window = self->window_size;
 832
 833 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 834         /* Remove what we have not used. Just do a prorata of the
 835          * bytes left in window to window capacity.
 836          * See max_line_capacities[][] in qos.c for details. Jean II */
 837         transmission_time -= (self->final_timeout * self->bytes_left
 838                               / self->line_capacity);
 839         IRDA_DEBUG(4, "%s() adjusting transmission_time : ft=%d, bl=%d, lc=%d -> tt=%d\n", __func__, self->final_timeout, self->bytes_left, self->line_capacity, transmission_time);
 840
 841         /* We are allowed to transmit a maximum number of bytes again. */
 842         self->bytes_left = self->line_capacity;
 843 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 844
 845         /*
 846          * The network layer has a intermediate buffer between IrLAP
 847          * and the IrDA driver which can contain 8 frames. So, even
 848          * though IrLAP is currently sending the *last* frame of the
 849          * tx-window, the driver most likely has only just started
 850          * sending the *first* frame of the same tx-window.
 851          * I.e. we are always at the very beginning of or Tx window.
 852          * Now, we are supposed to set the final timer from the end
 853          * of our tx-window to let the other peer reply. So, we need
 854          * to add extra time to compensate for the fact that we
 855          * are really at the start of tx-window, otherwise the final timer
 856          * might expire before he can answer...
 857          * Jean II
 858          */
 859         irlap_start_final_timer(self, self->final_timeout + transmission_time);
 860
 861         /*
 862          * The clever amongst you might ask why we do this adjustement
 863          * only here, and not in all the other cases in irlap_event.c.
 864          * In all those other case, we only send a very short management
 865          * frame (few bytes), so the adjustement would be lost in the
 866          * noise...
 867          * The exception of course is irlap_resend_rejected_frame().
 868          * Jean II */
 869 }
 870
 871 /*
 872  * Function irlap_send_data_secondary_final (self, skb)
 873  *
 874  *    Send I(nformation) frame as secondary with final bit set
 875  *
 876  */
 877 void irlap_send_data_secondary_final(struct irlap_cb *self,
 878                                      struct sk_buff *skb)
 879 {
 880         struct sk_buff *tx_skb = NULL;
 881
 882         IRDA_ASSERT(self != NULL, return;);
 883         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 884         IRDA_ASSERT(skb != NULL, return;);
 885
 886         /* Is this reliable or unreliable data? */
 887         if (skb->data[1] == I_FRAME) {
 888
 889                 /*
 890                  *  Insert frame sequence number (Vs) in control field before
 891                  *  inserting into transmit window queue.
 892                  */
 893                 skb->data[1] = I_FRAME | (self->vs << 1);
 894
 895                 /*
 896                  *  Insert frame in store, in case of retransmissions
 897                  *  Increase skb reference count, see irlap_do_event()
 898                  */
 899                 skb_get(skb);
 900                 skb_queue_tail(&self->wx_list, skb);
 901
 902                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 903                 if (tx_skb == NULL) {
 904                         return;
 905                 }
 906
 907                 tx_skb->data[1] |= PF_BIT;
 908
 909                 self->vs = (self->vs + 1) % 8;
 910                 self->ack_required = FALSE;
 911
 912                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 913         } else {
 914                 if (self->ack_required) {
 915                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 916                         irlap_send_rr_frame(self, RSP_FRAME);
 917                         self->ack_required = FALSE;
 918                 } else {
 919                         skb->data[1] |= PF_BIT;
 920                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 921                 }
 922         }
 923
 924         self->window = self->window_size;
 925 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 926         /* We are allowed to transmit a maximum number of bytes again. */
 927         self->bytes_left = self->line_capacity;
 928 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 929
 930         irlap_start_wd_timer(self, self->wd_timeout);
 931 }
 932
 933 /*
 934  * Function irlap_send_data_secondary (self, skb)
 935  *
 936  *    Send I(nformation) frame as secondary without final bit set
 937  *
 938  */
 939 void irlap_send_data_secondary(struct irlap_cb *self, struct sk_buff *skb)
 940 {
 941         struct sk_buff *tx_skb = NULL;
 942
 943         /* Is this reliable or unreliable data? */
 944         if (skb->data[1] == I_FRAME) {
 945
 946                 /*
 947                  *  Insert frame sequence number (Vs) in control field before
 948                  *  inserting into transmit window queue.
 949                  */
 950                 skb->data[1] = I_FRAME | (self->vs << 1);
 951
 952                 /*
 953                  *  Insert frame in store, in case of retransmissions
 954                  *  Increase skb reference count, see irlap_do_event()
 955                  */
 956                 skb_get(skb);
 957                 skb_queue_tail(&self->wx_list, skb);
 958
 959                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 960                 if (tx_skb == NULL) {
 961                         return;
 962                 }
 963
 964                 self->vs = (self->vs + 1) % 8;
 965                 self->ack_required = FALSE;
 966                 self->window -= 1;
 967
 968                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 969         } else {
 970                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 971                 self->window -= 1;
 972         }
 973 }
 974
 975 /*
 976  * Function irlap_resend_rejected_frames (nr)
 977  *
 978  *    Resend frames which has not been acknowledged. Should be safe to
 979  *    traverse the list without locking it since this function will only be
 980  *    called from interrupt context (BH)
 981  */
 982 void irlap_resend_rejected_frames(struct irlap_cb *self, int command)
 983 {
 984         struct sk_buff *tx_skb;
 985         struct sk_buff *skb;
 986
 987         IRDA_ASSERT(self != NULL, return;);
 988         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 989
 990         /*  Resend unacknowledged frame(s) */
 991         skb_queue_walk(&self->wx_list, skb) {
 992                 irlap_wait_min_turn_around(self, &self->qos_tx);
 993
 994                 /* We copy the skb to be retransmitted since we will have to
 995                  * modify it. Cloning will confuse packet sniffers
 996                  */
 997                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
 998                 tx_skb = skb_copy(skb, GFP_ATOMIC);
 999                 if (!tx_skb) {
1000                         IRDA_DEBUG(0, "%s(), unable to copy\n", __func__);
1001                         return;
1002                 }
1003
1004                 /* Clear old Nr field + poll bit */
1005                 tx_skb->data[1] &= 0x0f;
1006
1007                 /*
1008                  *  Set poll bit on the last frame retransmitted
1009                  */
1010                 if (skb_queue_is_last(&self->wx_list, skb))
1011                         tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1012                 else
1013                         tx_skb->data[1] &= ~PF_BIT; /* Clear p/f bit */
1014
1015                 irlap_send_i_frame(self, tx_skb, command);
1016         }
1017 #if 0 /* Not yet */
1018         /*
1019          *  We can now fill the window with additional data frames
1020          */
1021         while (!skb_queue_empty(&self->txq)) {
1022
1023                 IRDA_DEBUG(0, "%s(), sending additional frames!\n", __func__);
1024                 if (self->window > 0) {
1025                         skb = skb_dequeue( &self->txq);
1026                         IRDA_ASSERT(skb != NULL, return;);
1027
1028                         /*
1029                          *  If send window > 1 then send frame with pf
1030                          *  bit cleared
1031                          */
1032                         if ((self->window > 1) &&
1033                             !skb_queue_empty(&self->txq)) {
1034                                 irlap_send_data_primary(self, skb);
1035                         } else {
1036                                 irlap_send_data_primary_poll(self, skb);
1037                         }
1038                         kfree_skb(skb);
1039                 }
1040         }
1041 #endif
1042 }
1043
1044 void irlap_resend_rejected_frame(struct irlap_cb *self, int command)
1045 {
1046         struct sk_buff *tx_skb;
1047         struct sk_buff *skb;
1048
1049         IRDA_ASSERT(self != NULL, return;);
1050         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1051
1052         /*  Resend unacknowledged frame(s) */
1053         skb = skb_peek(&self->wx_list);
1054         if (skb != NULL) {
1055                 irlap_wait_min_turn_around(self, &self->qos_tx);
1056
1057                 /* We copy the skb to be retransmitted since we will have to
1058                  * modify it. Cloning will confuse packet sniffers
1059                  */
1060                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1061                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1062                 if (!tx_skb) {
1063                         IRDA_DEBUG(0, "%s(), unable to copy\n", __func__);
1064                         return;
1065                 }
1066
1067                 /* Clear old Nr field + poll bit */
1068                 tx_skb->data[1] &= 0x0f;
1069
1070                 /*  Set poll/final bit */
1071                 tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1072
1073                 irlap_send_i_frame(self, tx_skb, command);
1074         }
1075 }
1076
1077 /*
1078  * Function irlap_send_ui_frame (self, skb, command)
1079  *
1080  *    Contruct and transmit an Unnumbered Information (UI) frame
1081  *
1082  */
1083 void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1084                          __u8 caddr, int command)
1085 {
1086         IRDA_DEBUG(4, "%s()\n", __func__);
1087
1088         IRDA_ASSERT(self != NULL, return;);
1089         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1090         IRDA_ASSERT(skb != NULL, return;);
1091
1092         /* Insert connection address */
1093         skb->data[0] = caddr | ((command) ? CMD_FRAME : 0);
1094
1095         irlap_queue_xmit(self, skb);
1096 }
1097
1098 /*
1099  * Function irlap_send_i_frame (skb)
1100  *
1101  *    Contruct and transmit Information (I) frame
1102  */
1103 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
1104                                int command)
1105 {
1106         /* Insert connection address */
1107         skb->data[0] = self->caddr;
1108         skb->data[0] |= (command) ? CMD_FRAME : 0;
1109
1110         /* Insert next to receive (Vr) */
1111         skb->data[1] |= (self->vr << 5);  /* insert nr */
1112
1113         irlap_queue_xmit(self, skb);
1114 }
1115
1116 /*
1117  * Function irlap_recv_i_frame (skb, frame)
1118  *
1119  *    Receive and parse an I (Information) frame, no harm in making it inline
1120  *    since it's called only from one single place (irlap_driver_rcv).
1121  */
1122 static inline void irlap_recv_i_frame(struct irlap_cb *self,
1123                                       struct sk_buff *skb,
1124                                       struct irlap_info *info, int command)
1125 {
1126         info->nr = skb->data[1] >> 5;          /* Next to receive */
1127         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1128         info->ns = (skb->data[1] >> 1) & 0x07; /* Next to send */
1129
1130         /* Check if this is a command or a response frame */
1131         if (command)
1132                 irlap_do_event(self, RECV_I_CMD, skb, info);
1133         else
1134                 irlap_do_event(self, RECV_I_RSP, skb, info);
1135 }
1136
1137 /*
1138  * Function irlap_recv_ui_frame (self, skb, info)
1139  *
1140  *    Receive and parse an Unnumbered Information (UI) frame
1141  *
1142  */
1143 static void irlap_recv_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1144                                 struct irlap_info *info)
1145 {
1146         IRDA_DEBUG( 4, "%s()\n", __func__);
1147
1148         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1149
1150         irlap_do_event(self, RECV_UI_FRAME, skb, info);
1151 }
1152
1153 /*
1154  * Function irlap_recv_frmr_frame (skb, frame)
1155  *
1156  *    Received Frame Reject response.
1157  *
1158  */
1159 static void irlap_recv_frmr_frame(struct irlap_cb *self, struct sk_buff *skb,
1160                                   struct irlap_info *info)
1161 {
1162         __u8 *frame;
1163         int w, x, y, z;
1164
1165         IRDA_DEBUG(0, "%s()\n", __func__);
1166
1167         IRDA_ASSERT(self != NULL, return;);
1168         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1169         IRDA_ASSERT(skb != NULL, return;);
1170         IRDA_ASSERT(info != NULL, return;);
1171
1172         if (!pskb_may_pull(skb, 4)) {
1173                 IRDA_ERROR("%s: frame too short!\n", __func__);
1174                 return;
1175         }
1176
1177         frame = skb->data;
1178
1179         info->nr = frame[2] >> 5;          /* Next to receive */
1180         info->pf = frame[2] & PF_BIT;      /* Final bit */
1181         info->ns = (frame[2] >> 1) & 0x07; /* Next to send */
1182
1183         w = frame[3] & 0x01;
1184         x = frame[3] & 0x02;
1185         y = frame[3] & 0x04;
1186         z = frame[3] & 0x08;
1187
1188         if (w) {
1189                 IRDA_DEBUG(0, "Rejected control field is undefined or not "
1190                       "implemented.\n");
1191         }
1192         if (x) {
1193                 IRDA_DEBUG(0, "Rejected control field was invalid because it "
1194                       "contained a non permitted I field.\n");
1195         }
1196         if (y) {
1197                 IRDA_DEBUG(0, "Received I field exceeded the maximum negotiated "
1198                       "for the existing connection or exceeded the maximum "
1199                       "this station supports if no connection exists.\n");
1200         }
1201         if (z) {
1202                 IRDA_DEBUG(0, "Rejected control field control field contained an "
1203                       "invalid Nr count.\n");
1204         }
1205         irlap_do_event(self, RECV_FRMR_RSP, skb, info);
1206 }
1207
1208 /*
1209  * Function irlap_send_test_frame (self, daddr)
1210  *
1211  *    Send a test frame response
1212  *
1213  */
1214 void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr,
1215                            struct sk_buff *cmd)
1216 {
1217         struct sk_buff *tx_skb;
1218         struct test_frame *frame;
1219         __u8 *info;
1220
1221         tx_skb = alloc_skb(cmd->len + sizeof(struct test_frame), GFP_ATOMIC);
1222         if (!tx_skb)
1223                 return;
1224
1225         /* Broadcast frames must include saddr and daddr fields */
1226         if (caddr == CBROADCAST) {
1227                 frame = (struct test_frame *)
1228                         skb_put(tx_skb, sizeof(struct test_frame));
1229
1230                 /* Insert the swapped addresses */
1231                 frame->saddr = cpu_to_le32(self->saddr);
1232                 frame->daddr = cpu_to_le32(daddr);
1233         } else
1234                 frame = (struct test_frame *) skb_put(tx_skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);
1235
1236         frame->caddr = caddr;
1237         frame->control = TEST_RSP | PF_BIT;
1238
1239         /* Copy info */
1240         info = skb_put(tx_skb, cmd->len);
1241         memcpy(info, cmd->data, cmd->len);
1242
1243         /* Return to sender */
1244         irlap_wait_min_turn_around(self, &self->qos_tx);
1245         irlap_queue_xmit(self, tx_skb);
1246 }
1247
1248 /*
1249  * Function irlap_recv_test_frame (self, skb)
1250  *
1251  *    Receive a test frame
1252  *
1253  */
1254 static void irlap_recv_test_frame(struct irlap_cb *self, struct sk_buff *skb,
1255                                   struct irlap_info *info, int command)
1256 {
1257         struct test_frame *frame;
1258
1259         IRDA_DEBUG(2, "%s()\n", __func__);
1260
1261         if (!pskb_may_pull(skb, sizeof(*frame))) {
1262                 IRDA_ERROR("%s: frame too short!\n", __func__);
1263                 return;
1264         }
1265         frame = (struct test_frame *) skb->data;
1266
1267         /* Broadcast frames must carry saddr and daddr fields */
1268         if (info->caddr == CBROADCAST) {
1269                 if (skb->len < sizeof(struct test_frame)) {
1270                         IRDA_DEBUG(0, "%s() test frame too short!\n",
1271                                    __func__);
1272                         return;
1273                 }
1274
1275                 /* Read and swap addresses */
1276                 info->daddr = le32_to_cpu(frame->saddr);
1277                 info->saddr = le32_to_cpu(frame->daddr);
1278
1279                 /* Make sure frame is addressed to us */
1280                 if ((info->saddr != self->saddr) &&
1281                     (info->saddr != BROADCAST)) {
1282                         return;
1283                 }
1284         }
1285
1286         if (command)
1287                 irlap_do_event(self, RECV_TEST_CMD, skb, info);
1288         else
1289                 irlap_do_event(self, RECV_TEST_RSP, skb, info);
1290 }
1291
1292 /*
1293  * Function irlap_driver_rcv (skb, netdev, ptype)
1294  *
1295  *    Called when a frame is received. Dispatches the right receive function
1296  *    for processing of the frame.
1297  *
1298  * Note on skb management :
1299  * After calling the higher layers of the IrDA stack, we always
1300  * kfree() the skb, which drop the reference count (and potentially
1301  * destroy it).
1302  * If a higher layer of the stack want to keep the skb around (to put
1303  * in a queue or pass it to the higher layer), it will need to use
1304  * skb_get() to keep a reference on it. This is usually done at the
1305  * LMP level in irlmp.c.
1306  * Jean II
1307  */
1308 int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,
1309                      struct packet_type *ptype, struct net_device *orig_dev)
1310 {
1311         struct irlap_info info;
1312         struct irlap_cb *self;
1313         int command;
1314         __u8 control;
1315         int ret = -1;
1316
1317         if (!net_eq(dev_net(dev), &init_net))
1318                 goto out;
1319
1320         /* FIXME: should we get our own field? */
1321         self = (struct irlap_cb *) dev->atalk_ptr;
1322
1323         /* If the net device is down, then IrLAP is gone! */
1324         if (!self || self->magic != LAP_MAGIC)
1325                 goto err;
1326
1327         /* We are no longer an "old" protocol, so we need to handle
1328          * share and non linear skbs. This should never happen, so
1329          * we don't need to be clever about it. Jean II */
1330         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
1331                 IRDA_ERROR("%s: can't clone shared skb!\n", __func__);
1332                 goto err;
1333         }
1334
1335         /* Check if frame is large enough for parsing */
1336         if (!pskb_may_pull(skb, 2)) {
1337                 IRDA_ERROR("%s: frame too short!\n", __func__);
1338                 goto err;
1339         }
1340
1341         command    = skb->data[0] & CMD_FRAME;
1342         info.caddr = skb->data[0] & CBROADCAST;
1343
1344         info.pf      = skb->data[1] &  PF_BIT;
1345         info.control = skb->data[1] & ~PF_BIT; /* Mask away poll/final bit */
1346
1347         control = info.control;
1348
1349         /*  First we check if this frame has a valid connection address */
1350         if ((info.caddr != self->caddr) && (info.caddr != CBROADCAST)) {
1351                 IRDA_DEBUG(0, "%s(), wrong connection address!\n",
1352                            __func__);
1353                 goto out;
1354         }
1355         /*
1356          *  Optimize for the common case and check if the frame is an
1357          *  I(nformation) frame. Only I-frames have bit 0 set to 0
1358          */
1359         if (~control & 0x01) {
1360                 irlap_recv_i_frame(self, skb, &info, command);
1361                 goto out;
1362         }
1363         /*
1364          *  We now check is the frame is an S(upervisory) frame. Only
1365          *  S-frames have bit 0 set to 1 and bit 1 set to 0
1366          */
1367         if (~control & 0x02) {
1368                 /*
1369                  *  Received S(upervisory) frame, check which frame type it is
1370                  *  only the first nibble is of interest
1371                  */
1372                 switch (control & 0x0f) {
1373                 case RR:
1374                         irlap_recv_rr_frame(self, skb, &info, command);
1375                         break;
1376                 case RNR:
1377                         irlap_recv_rnr_frame(self, skb, &info, command);
1378                         break;
1379                 case REJ:
1380                         irlap_recv_rej_frame(self, skb, &info, command);
1381                         break;
1382                 case SREJ:
1383                         irlap_recv_srej_frame(self, skb, &info, command);
1384                         break;
1385                 default:
1386                         IRDA_WARNING("%s: Unknown S-frame %02x received!\n",
1387                                 __func__, info.control);
1388                         break;
1389                 }
1390                 goto out;
1391         }
1392         /*
1393          *  This must be a C(ontrol) frame
1394          */
1395         switch (control) {
1396         case XID_RSP:
1397                 irlap_recv_discovery_xid_rsp(self, skb, &info);
1398                 break;
1399         case XID_CMD:
1400                 irlap_recv_discovery_xid_cmd(self, skb, &info);
1401                 break;
1402         case SNRM_CMD:
1403                 irlap_recv_snrm_cmd(self, skb, &info);
1404                 break;
1405         case DM_RSP:
1406                 irlap_do_event(self, RECV_DM_RSP, skb, &info);
1407                 break;
1408         case DISC_CMD: /* And RD_RSP since they have the same value */
1409                 irlap_recv_disc_frame(self, skb, &info, command);
1410                 break;
1411         case TEST_CMD:
1412                 irlap_recv_test_frame(self, skb, &info, command);
1413                 break;
1414         case UA_RSP:
1415                 irlap_recv_ua_frame(self, skb, &info);
1416                 break;
1417         case FRMR_RSP:
1418                 irlap_recv_frmr_frame(self, skb, &info);
1419                 break;
1420         case UI_FRAME:
1421                 irlap_recv_ui_frame(self, skb, &info);
1422                 break;
1423         default:
1424                 IRDA_WARNING("%s: Unknown frame %02x received!\n",
1425                                 __func__, info.control);
1426                 break;
1427         }
1428 out:
1429         ret = 0;
1430 err:
1431         /* Always drop our reference on the skb */
1432         dev_kfree_skb(skb);
1433         return ret;
1434 }