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
  33 #include <net/pkt_sched.h>
  34 #include <net/sock.h>
  35
  36 #include <asm/byteorder.h>
  37
  38 #include <net/irda/irda.h>
  39 #include <net/irda/irda_device.h>
  40 #include <net/irda/irlap.h>
  41 #include <net/irda/wrapper.h>
  42 #include <net/irda/timer.h>
  43 #include <net/irda/irlap_frame.h>
  44 #include <net/irda/qos.h>
  45
  46 /*
  47  * Function irlap_insert_info (self, skb)
  48  *
  49  *    Insert minimum turnaround time and speed information into the skb. We
  50  *    need to do this since it's per packet relevant information. Safe to
  51  *    have this function inlined since it's only called from one place
  52  */
  53 static inline void irlap_insert_info(struct irlap_cb *self,
  54                                      struct sk_buff *skb)
  55 {
  56         struct irda_skb_cb *cb = (struct irda_skb_cb *) skb->cb;
  57
  58         /*
  59          * Insert MTT (min. turn time) and speed into skb, so that the
  60          * device driver knows which settings to use
  61          */
  62         cb->magic = LAP_MAGIC;
  63         cb->mtt = self->mtt_required;
  64         cb->next_speed = self->speed;
  65
  66         /* Reset */
  67         self->mtt_required = 0;
  68
  69         /*
  70          * Delay equals negotiated BOFs count, plus the number of BOFs to
  71          * force the negotiated minimum turnaround time
  72          */
  73         cb->xbofs = self->bofs_count;
  74         cb->next_xbofs = self->next_bofs;
  75         cb->xbofs_delay = self->xbofs_delay;
  76
  77         /* Reset XBOF's delay (used only for getting min turn time) */
  78         self->xbofs_delay = 0;
  79         /* Put the correct xbofs value for the next packet */
  80         self->bofs_count = self->next_bofs;
  81 }
  82
  83 /*
  84  * Function irlap_queue_xmit (self, skb)
  85  *
  86  *    A little wrapper for dev_queue_xmit, so we can insert some common
  87  *    code into it.
  88  */
  89 void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb)
  90 {
  91         /* Some common init stuff */
  92         skb->dev = self->netdev;
  93         skb->h.raw = skb->nh.raw = skb->mac.raw = skb->data;
  94         skb->protocol = htons(ETH_P_IRDA);
  95         skb->priority = TC_PRIO_BESTEFFORT;
  96
  97         irlap_insert_info(self, skb);
  98
  99         dev_queue_xmit(skb);
 100 }
 101
 102 /*
 103  * Function irlap_send_snrm_cmd (void)
 104  *
 105  *    Transmits a connect SNRM command frame
 106  */
 107 void irlap_send_snrm_frame(struct irlap_cb *self, struct qos_info *qos)
 108 {
 109         struct sk_buff *tx_skb;
 110         struct snrm_frame *frame;
 111         int ret;
 112
 113         ASSERT(self != NULL, return;);
 114         ASSERT(self->magic == LAP_MAGIC, return;);
 115
 116         /* Allocate frame */
 117         tx_skb = dev_alloc_skb(64);
 118         if (!tx_skb)
 119                 return;
 120
 121         frame = (struct snrm_frame *) skb_put(tx_skb, 2);
 122
 123         /* Insert connection address field */
 124         if (qos)
 125                 frame->caddr = CMD_FRAME | CBROADCAST;
 126         else
 127                 frame->caddr = CMD_FRAME | self->caddr;
 128
 129         /* Insert control field */
 130         frame->control = SNRM_CMD | PF_BIT;
 131
 132         /*
 133          *  If we are establishing a connection then insert QoS paramerters
 134          */
 135         if (qos) {
 136                 skb_put(tx_skb, 9); /* 21 left */
 137                 frame->saddr = cpu_to_le32(self->saddr);
 138                 frame->daddr = cpu_to_le32(self->daddr);
 139
 140                 frame->ncaddr = self->caddr;
 141
 142                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 143                 if (ret < 0) {
 144                         dev_kfree_skb(tx_skb);
 145                         return;
 146                 }
 147         }
 148         irlap_queue_xmit(self, tx_skb);
 149 }
 150
 151 /*
 152  * Function irlap_recv_snrm_cmd (skb, info)
 153  *
 154  *    Received SNRM (Set Normal Response Mode) command frame
 155  *
 156  */
 157 static void irlap_recv_snrm_cmd(struct irlap_cb *self, struct sk_buff *skb,
 158                                 struct irlap_info *info)
 159 {
 160         struct snrm_frame *frame;
 161
 162         if (pskb_may_pull(skb,sizeof(struct snrm_frame))) {
 163                 frame = (struct snrm_frame *) skb->data;
 164
 165                 /* Copy the new connection address ignoring the C/R bit */
 166                 info->caddr = frame->ncaddr & 0xFE;
 167
 168                 /* Check if the new connection address is valid */
 169                 if ((info->caddr == 0x00) || (info->caddr == 0xfe)) {
 170                         IRDA_DEBUG(3, "%s(), invalid connection address!\n",
 171                                    __FUNCTION__);
 172                         return;
 173                 }
 174
 175                 /* Copy peer device address */
 176                 info->daddr = le32_to_cpu(frame->saddr);
 177                 info->saddr = le32_to_cpu(frame->daddr);
 178
 179                 /* Only accept if addressed directly to us */
 180                 if (info->saddr != self->saddr) {
 181                         IRDA_DEBUG(2, "%s(), not addressed to us!\n",
 182                                    __FUNCTION__);
 183                         return;
 184                 }
 185                 irlap_do_event(self, RECV_SNRM_CMD, skb, info);
 186         } else {
 187                 /* Signal that this SNRM frame does not contain and I-field */
 188                 irlap_do_event(self, RECV_SNRM_CMD, skb, NULL);
 189         }
 190 }
 191
 192 /*
 193  * Function irlap_send_ua_response_frame (qos)
 194  *
 195  *    Send UA (Unnumbered Acknowledgement) frame
 196  *
 197  */
 198 void irlap_send_ua_response_frame(struct irlap_cb *self, struct qos_info *qos)
 199 {
 200         struct sk_buff *tx_skb;
 201         struct ua_frame *frame;
 202         int ret;
 203
 204         IRDA_DEBUG(2, "%s() <%ld>\n", __FUNCTION__, jiffies);
 205
 206         ASSERT(self != NULL, return;);
 207         ASSERT(self->magic == LAP_MAGIC, return;);
 208
 209         /* Allocate frame */
 210         tx_skb = dev_alloc_skb(64);
 211         if (!tx_skb)
 212                 return;
 213
 214         frame = (struct ua_frame *) skb_put(tx_skb, 10);
 215
 216         /* Build UA response */
 217         frame->caddr = self->caddr;
 218         frame->control = UA_RSP | PF_BIT;
 219
 220         frame->saddr = cpu_to_le32(self->saddr);
 221         frame->daddr = cpu_to_le32(self->daddr);
 222
 223         /* Should we send QoS negotiation parameters? */
 224         if (qos) {
 225                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 226                 if (ret < 0) {
 227                         dev_kfree_skb(tx_skb);
 228                         return;
 229                 }
 230         }
 231
 232         irlap_queue_xmit(self, tx_skb);
 233 }
 234
 235
 236 /*
 237  * Function irlap_send_dm_frame (void)
 238  *
 239  *    Send disconnected mode (DM) frame
 240  *
 241  */
 242 void irlap_send_dm_frame( struct irlap_cb *self)
 243 {
 244         struct sk_buff *tx_skb = NULL;
 245         __u8 *frame;
 246
 247         ASSERT(self != NULL, return;);
 248         ASSERT(self->magic == LAP_MAGIC, return;);
 249
 250         tx_skb = dev_alloc_skb(32);
 251         if (!tx_skb)
 252                 return;
 253
 254         frame = skb_put(tx_skb, 2);
 255
 256         if (self->state == LAP_NDM)
 257                 frame[0] = CBROADCAST;
 258         else
 259                 frame[0] = self->caddr;
 260
 261         frame[1] = DM_RSP | PF_BIT;
 262
 263         irlap_queue_xmit(self, tx_skb);
 264 }
 265
 266 /*
 267  * Function irlap_send_disc_frame (void)
 268  *
 269  *    Send disconnect (DISC) frame
 270  *
 271  */
 272 void irlap_send_disc_frame(struct irlap_cb *self)
 273 {
 274         struct sk_buff *tx_skb = NULL;
 275         __u8 *frame;
 276
 277         IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
 278
 279         ASSERT(self != NULL, return;);
 280         ASSERT(self->magic == LAP_MAGIC, return;);
 281
 282         tx_skb = dev_alloc_skb(16);
 283         if (!tx_skb)
 284                 return;
 285
 286         frame = skb_put(tx_skb, 2);
 287
 288         frame[0] = self->caddr | CMD_FRAME;
 289         frame[1] = DISC_CMD | PF_BIT;
 290
 291         irlap_queue_xmit(self, tx_skb);
 292 }
 293
 294 /*
 295  * Function irlap_send_discovery_xid_frame (S, s, command)
 296  *
 297  *    Build and transmit a XID (eXchange station IDentifier) discovery
 298  *    frame.
 299  */
 300 void irlap_send_discovery_xid_frame(struct irlap_cb *self, int S, __u8 s,
 301                                     __u8 command, discovery_t *discovery)
 302 {
 303         struct sk_buff *tx_skb = NULL;
 304         struct xid_frame *frame;
 305         __u32 bcast = BROADCAST;
 306         __u8 *info;
 307
 308         IRDA_DEBUG(4, "%s(), s=%d, S=%d, command=%d\n", __FUNCTION__,
 309                    s, S, command);
 310
 311         ASSERT(self != NULL, return;);
 312         ASSERT(self->magic == LAP_MAGIC, return;);
 313         ASSERT(discovery != NULL, return;);
 314
 315         tx_skb = dev_alloc_skb(64);
 316         if (!tx_skb)
 317                 return;
 318
 319         skb_put(tx_skb, 14);
 320         frame = (struct xid_frame *) tx_skb->data;
 321
 322         if (command) {
 323                 frame->caddr = CBROADCAST | CMD_FRAME;
 324                 frame->control =  XID_CMD | PF_BIT;
 325         } else {
 326                 frame->caddr = CBROADCAST;
 327                 frame->control =  XID_RSP | PF_BIT;
 328         }
 329         frame->ident = XID_FORMAT;
 330
 331         frame->saddr = cpu_to_le32(self->saddr);
 332
 333         if (command)
 334                 frame->daddr = cpu_to_le32(bcast);
 335         else
 336                 frame->daddr = cpu_to_le32(discovery->data.daddr);
 337
 338         switch (S) {
 339         case 1:
 340                 frame->flags = 0x00;
 341                 break;
 342         case 6:
 343                 frame->flags = 0x01;
 344                 break;
 345         case 8:
 346                 frame->flags = 0x02;
 347                 break;
 348         case 16:
 349                 frame->flags = 0x03;
 350                 break;
 351         default:
 352                 frame->flags = 0x02;
 353                 break;
 354         }
 355
 356         frame->slotnr = s;
 357         frame->version = 0x00;
 358
 359         /*
 360          *  Provide info for final slot only in commands, and for all
 361          *  responses. Send the second byte of the hint only if the
 362          *  EXTENSION bit is set in the first byte.
 363          */
 364         if (!command || (frame->slotnr == 0xff)) {
 365                 int len;
 366
 367                 if (discovery->data.hints[0] & HINT_EXTENSION) {
 368                         info = skb_put(tx_skb, 2);
 369                         info[0] = discovery->data.hints[0];
 370                         info[1] = discovery->data.hints[1];
 371                 } else {
 372                         info = skb_put(tx_skb, 1);
 373                         info[0] = discovery->data.hints[0];
 374                 }
 375                 info = skb_put(tx_skb, 1);
 376                 info[0] = discovery->data.charset;
 377
 378                 len = IRDA_MIN(discovery->name_len, skb_tailroom(tx_skb));
 379                 info = skb_put(tx_skb, len);
 380                 memcpy(info, discovery->data.info, len);
 381         }
 382         irlap_queue_xmit(self, tx_skb);
 383 }
 384
 385 /*
 386  * Function irlap_recv_discovery_xid_rsp (skb, info)
 387  *
 388  *    Received a XID discovery response
 389  *
 390  */
 391 static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
 392                                          struct sk_buff *skb,
 393                                          struct irlap_info *info)
 394 {
 395         struct xid_frame *xid;
 396         discovery_t *discovery = NULL;
 397         __u8 *discovery_info;
 398         char *text;
 399
 400         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 401
 402         ASSERT(self != NULL, return;);
 403         ASSERT(self->magic == LAP_MAGIC, return;);
 404
 405         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 406                 ERROR("%s: frame to short!\n", __FUNCTION__);
 407                 return;
 408         }
 409
 410         xid = (struct xid_frame *) skb->data;
 411
 412         info->daddr = le32_to_cpu(xid->saddr);
 413         info->saddr = le32_to_cpu(xid->daddr);
 414
 415         /* Make sure frame is addressed to us */
 416         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 417                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 418                            __FUNCTION__);
 419                 return;
 420         }
 421
 422         if ((discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {
 423                 WARNING("%s: kmalloc failed!\n", __FUNCTION__);
 424                 return;
 425         }
 426         memset(discovery, 0, sizeof(discovery_t));
 427
 428         discovery->data.daddr = info->daddr;
 429         discovery->data.saddr = self->saddr;
 430         discovery->timestamp = jiffies;
 431
 432         IRDA_DEBUG(4, "%s(), daddr=%08x\n", __FUNCTION__,
 433                    discovery->data.daddr);
 434
 435         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 436
 437         /* Get info returned from peer */
 438         discovery->data.hints[0] = discovery_info[0];
 439         if (discovery_info[0] & HINT_EXTENSION) {
 440                 IRDA_DEBUG(4, "EXTENSION\n");
 441                 discovery->data.hints[1] = discovery_info[1];
 442                 discovery->data.charset = discovery_info[2];
 443                 text = (char *) &discovery_info[3];
 444         } else {
 445                 discovery->data.hints[1] = 0;
 446                 discovery->data.charset = discovery_info[1];
 447                 text = (char *) &discovery_info[2];
 448         }
 449         /*
 450          *  Terminate info string, should be safe since this is where the
 451          *  FCS bytes resides.
 452          */
 453         skb->data[skb->len] = '\0';
 454         strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 455         discovery->name_len = strlen(discovery->data.info);
 456
 457         info->discovery = discovery;
 458
 459         irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
 460 }
 461
 462 /*
 463  * Function irlap_recv_discovery_xid_cmd (skb, info)
 464  *
 465  *    Received a XID discovery command
 466  *
 467  */
 468 static void irlap_recv_discovery_xid_cmd(struct irlap_cb *self,
 469                                          struct sk_buff *skb,
 470                                          struct irlap_info *info)
 471 {
 472         struct xid_frame *xid;
 473         discovery_t *discovery = NULL;
 474         __u8 *discovery_info;
 475         char *text;
 476
 477         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 478                 ERROR("%s: frame to short!\n", __FUNCTION__);
 479                 return;
 480         }
 481
 482         xid = (struct xid_frame *) skb->data;
 483
 484         info->daddr = le32_to_cpu(xid->saddr);
 485         info->saddr = le32_to_cpu(xid->daddr);
 486
 487         /* Make sure frame is addressed to us */
 488         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 489                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 490                            __FUNCTION__);
 491                 return;
 492         }
 493
 494         switch (xid->flags & 0x03) {
 495         case 0x00:
 496                 info->S = 1;
 497                 break;
 498         case 0x01:
 499                 info->S = 6;
 500                 break;
 501         case 0x02:
 502                 info->S = 8;
 503                 break;
 504         case 0x03:
 505                 info->S = 16;
 506                 break;
 507         default:
 508                 /* Error!! */
 509                 return;
 510         }
 511         info->s = xid->slotnr;
 512
 513         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 514
 515         /*
 516          *  Check if last frame
 517          */
 518         if (info->s == 0xff) {
 519                 /* Check if things are sane at this point... */
 520                 if((discovery_info == NULL) ||
 521                    !pskb_may_pull(skb, 3)) {
 522                         ERROR("%s: discovery frame to short!\n", __FUNCTION__);
 523                         return;
 524                 }
 525
 526                 /*
 527                  *  We now have some discovery info to deliver!
 528                  */
 529                 discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC);
 530                 if (!discovery) {
 531                         WARNING("%s: unable to malloc!\n", __FUNCTION__);
 532                         return;
 533                 }
 534
 535                 discovery->data.daddr = info->daddr;
 536                 discovery->data.saddr = self->saddr;
 537                 discovery->timestamp = jiffies;
 538
 539                 discovery->data.hints[0] = discovery_info[0];
 540                 if (discovery_info[0] & HINT_EXTENSION) {
 541                         discovery->data.hints[1] = discovery_info[1];
 542                         discovery->data.charset = discovery_info[2];
 543                         text = (char *) &discovery_info[3];
 544                 } else {
 545                         discovery->data.hints[1] = 0;
 546                         discovery->data.charset = discovery_info[1];
 547                         text = (char *) &discovery_info[2];
 548                 }
 549                 /*
 550                  *  Terminate string, should be safe since this is where the
 551                  *  FCS bytes resides.
 552                  */
 553                 skb->data[skb->len] = '\0';
 554                 strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 555                 discovery->name_len = strlen(discovery->data.info);
 556
 557                 info->discovery = discovery;
 558         } else
 559                 info->discovery = NULL;
 560
 561         irlap_do_event(self, RECV_DISCOVERY_XID_CMD, skb, info);
 562 }
 563
 564 /*
 565  * Function irlap_send_rr_frame (self, command)
 566  *
 567  *    Build and transmit RR (Receive Ready) frame. Notice that it is currently
 568  *    only possible to send RR frames with the poll bit set.
 569  */
 570 void irlap_send_rr_frame(struct irlap_cb *self, int command)
 571 {
 572         struct sk_buff *tx_skb;
 573         __u8 *frame;
 574
 575         tx_skb = dev_alloc_skb(16);
 576         if (!tx_skb)
 577                 return;
 578
 579         frame = skb_put(tx_skb, 2);
 580
 581         frame[0] = self->caddr;
 582         frame[0] |= (command) ? CMD_FRAME : 0;
 583
 584         frame[1] = RR | PF_BIT | (self->vr << 5);
 585
 586         irlap_queue_xmit(self, tx_skb);
 587 }
 588
 589 /*
 590  * Function irlap_send_rd_frame (self)
 591  *
 592  *    Request disconnect. Used by a secondary station to request the
 593  *    disconnection of the link.
 594  */
 595 void irlap_send_rd_frame(struct irlap_cb *self)
 596 {
 597         struct sk_buff *tx_skb;
 598         __u8 *frame;
 599
 600         tx_skb = dev_alloc_skb(16);
 601         if (!tx_skb)
 602                 return;
 603
 604         frame = skb_put(tx_skb, 2);
 605
 606         frame[0] = self->caddr;
 607         frame[1] = RD_RSP | PF_BIT;
 608
 609         irlap_queue_xmit(self, tx_skb);
 610 }
 611
 612 /*
 613  * Function irlap_recv_rr_frame (skb, info)
 614  *
 615  *    Received RR (Receive Ready) frame from peer station, no harm in
 616  *    making it inline since its called only from one single place
 617  *    (irlap_driver_rcv).
 618  */
 619 static inline void irlap_recv_rr_frame(struct irlap_cb *self,
 620                                        struct sk_buff *skb,
 621                                        struct irlap_info *info, int command)
 622 {
 623         info->nr = skb->data[1] >> 5;
 624
 625         /* Check if this is a command or a response frame */
 626         if (command)
 627                 irlap_do_event(self, RECV_RR_CMD, skb, info);
 628         else
 629                 irlap_do_event(self, RECV_RR_RSP, skb, info);
 630 }
 631
 632 void irlap_send_frmr_frame( struct irlap_cb *self, int command)
 633 {
 634         struct sk_buff *tx_skb = NULL;
 635         __u8 *frame;
 636
 637         ASSERT( self != NULL, return;);
 638         ASSERT( self->magic == LAP_MAGIC, return;);
 639
 640         tx_skb = dev_alloc_skb( 32);
 641         if (!tx_skb)
 642                 return;
 643
 644         frame = skb_put(tx_skb, 2);
 645
 646         frame[0] = self->caddr;
 647         frame[0] |= (command) ? CMD_FRAME : 0;
 648
 649         frame[1]  = (self->vs << 1);
 650         frame[1] |= PF_BIT;
 651         frame[1] |= (self->vr << 5);
 652
 653         frame[2] = 0;
 654
 655         IRDA_DEBUG(4, "%s(), vr=%d, %ld\n", __FUNCTION__, self->vr, jiffies);
 656
 657         irlap_queue_xmit(self, tx_skb);
 658 }
 659
 660 /*
 661  * Function irlap_recv_rnr_frame (self, skb, info)
 662  *
 663  *    Received RNR (Receive Not Ready) frame from peer station
 664  *
 665  */
 666 static void irlap_recv_rnr_frame(struct irlap_cb *self, struct sk_buff *skb,
 667                                  struct irlap_info *info, int command)
 668 {
 669         info->nr = skb->data[1] >> 5;
 670
 671         IRDA_DEBUG(4, "%s(), nr=%d, %ld\n", __FUNCTION__, info->nr, jiffies);
 672
 673         if (command)
 674                 irlap_do_event(self, RECV_RNR_CMD, skb, info);
 675         else
 676                 irlap_do_event(self, RECV_RNR_RSP, skb, info);
 677 }
 678
 679 static void irlap_recv_rej_frame(struct irlap_cb *self, struct sk_buff *skb,
 680                                  struct irlap_info *info, int command)
 681 {
 682         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 683
 684         info->nr = skb->data[1] >> 5;
 685
 686         /* Check if this is a command or a response frame */
 687         if (command)
 688                 irlap_do_event(self, RECV_REJ_CMD, skb, info);
 689         else
 690                 irlap_do_event(self, RECV_REJ_RSP, skb, info);
 691 }
 692
 693 static void irlap_recv_srej_frame(struct irlap_cb *self, struct sk_buff *skb,
 694                                   struct irlap_info *info, int command)
 695 {
 696         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 697
 698         info->nr = skb->data[1] >> 5;
 699
 700         /* Check if this is a command or a response frame */
 701         if (command)
 702                 irlap_do_event(self, RECV_SREJ_CMD, skb, info);
 703         else
 704                 irlap_do_event(self, RECV_SREJ_RSP, skb, info);
 705 }
 706
 707 static void irlap_recv_disc_frame(struct irlap_cb *self, struct sk_buff *skb,
 708                                   struct irlap_info *info, int command)
 709 {
 710         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 711
 712         /* Check if this is a command or a response frame */
 713         if (command)
 714                 irlap_do_event(self, RECV_DISC_CMD, skb, info);
 715         else
 716                 irlap_do_event(self, RECV_RD_RSP, skb, info);
 717 }
 718
 719 /*
 720  * Function irlap_recv_ua_frame (skb, frame)
 721  *
 722  *    Received UA (Unnumbered Acknowledgement) frame
 723  *
 724  */
 725 static inline void irlap_recv_ua_frame(struct irlap_cb *self,
 726                                        struct sk_buff *skb,
 727                                        struct irlap_info *info)
 728 {
 729         irlap_do_event(self, RECV_UA_RSP, skb, info);
 730 }
 731
 732 /*
 733  * Function irlap_send_data_primary(self, skb)
 734  *
 735  *    Send I-frames as the primary station but without the poll bit set
 736  *
 737  */
 738 void irlap_send_data_primary(struct irlap_cb *self, struct sk_buff *skb)
 739 {
 740         struct sk_buff *tx_skb;
 741
 742         if (skb->data[1] == I_FRAME) {
 743
 744                 /*
 745                  *  Insert frame sequence number (Vs) in control field before
 746                  *  inserting into transmit window queue.
 747                  */
 748                 skb->data[1] = I_FRAME | (self->vs << 1);
 749
 750                 /*
 751                  *  Insert frame in store, in case of retransmissions
 752                  *  Increase skb reference count, see irlap_do_event()
 753                  */
 754                 skb_get(skb);
 755                 skb_queue_tail(&self->wx_list, skb);
 756
 757                 /* Copy buffer */
 758                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 759                 if (tx_skb == NULL) {
 760                         return;
 761                 }
 762
 763                 self->vs = (self->vs + 1) % 8;
 764                 self->ack_required = FALSE;
 765                 self->window -= 1;
 766
 767                 irlap_send_i_frame( self, tx_skb, CMD_FRAME);
 768         } else {
 769                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 770                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 771                 self->window -= 1;
 772         }
 773 }
 774 /*
 775  * Function irlap_send_data_primary_poll (self, skb)
 776  *
 777  *    Send I(nformation) frame as primary with poll bit set
 778  */
 779 void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
 780 {
 781         struct sk_buff *tx_skb;
 782         int transmission_time;
 783
 784         /* Stop P timer */
 785         del_timer(&self->poll_timer);
 786
 787         /* Is this reliable or unreliable data? */
 788         if (skb->data[1] == I_FRAME) {
 789
 790                 /*
 791                  *  Insert frame sequence number (Vs) in control field before
 792                  *  inserting into transmit window queue.
 793                  */
 794                 skb->data[1] = I_FRAME | (self->vs << 1);
 795
 796                 /*
 797                  *  Insert frame in store, in case of retransmissions
 798                  *  Increase skb reference count, see irlap_do_event()
 799                  */
 800                 skb_get(skb);
 801                 skb_queue_tail(&self->wx_list, skb);
 802
 803                 /* Copy buffer */
 804                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 805                 if (tx_skb == NULL) {
 806                         return;
 807                 }
 808
 809                 /*
 810                  *  Set poll bit if necessary. We do this to the copied
 811                  *  skb, since retransmitted need to set or clear the poll
 812                  *  bit depending on when they are sent.
 813                  */
 814                 tx_skb->data[1] |= PF_BIT;
 815
 816                 self->vs = (self->vs + 1) % 8;
 817                 self->ack_required = FALSE;
 818
 819                 irlap_send_i_frame(self, tx_skb, CMD_FRAME);
 820         } else {
 821                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 822
 823                 if (self->ack_required) {
 824                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 825                         irlap_send_rr_frame(self, CMD_FRAME);
 826                         self->ack_required = FALSE;
 827                 } else {
 828                         skb->data[1] |= PF_BIT;
 829                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 830                 }
 831         }
 832
 833         /* How much time we took for transmission of all frames.
 834          * We don't know, so let assume we used the full window. Jean II */
 835         transmission_time = self->final_timeout;
 836
 837         /* Reset parameter so that we can fill next window */
 838         self->window = self->window_size;
 839
 840 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 841         /* Remove what we have not used. Just do a prorata of the
 842          * bytes left in window to window capacity.
 843          * See max_line_capacities[][] in qos.c for details. Jean II */
 844         transmission_time -= (self->final_timeout * self->bytes_left
 845                               / self->line_capacity);
 846         IRDA_DEBUG(4, "%s() adjusting transmission_time : ft=%d, bl=%d, lc=%d -> tt=%d\n", __FUNCTION__, self->final_timeout, self->bytes_left, self->line_capacity, transmission_time);
 847
 848         /* We are allowed to transmit a maximum number of bytes again. */
 849         self->bytes_left = self->line_capacity;
 850 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 851
 852         /*
 853          * The network layer has a intermediate buffer between IrLAP
 854          * and the IrDA driver which can contain 8 frames. So, even
 855          * though IrLAP is currently sending the *last* frame of the
 856          * tx-window, the driver most likely has only just started
 857          * sending the *first* frame of the same tx-window.
 858          * I.e. we are always at the very begining of or Tx window.
 859          * Now, we are supposed to set the final timer from the end
 860          * of our tx-window to let the other peer reply. So, we need
 861          * to add extra time to compensate for the fact that we
 862          * are really at the start of tx-window, otherwise the final timer
 863          * might expire before he can answer...
 864          * Jean II
 865          */
 866         irlap_start_final_timer(self, self->final_timeout + transmission_time);
 867
 868         /*
 869          * The clever amongst you might ask why we do this adjustement
 870          * only here, and not in all the other cases in irlap_event.c.
 871          * In all those other case, we only send a very short management
 872          * frame (few bytes), so the adjustement would be lost in the
 873          * noise...
 874          * The exception of course is irlap_resend_rejected_frame().
 875          * Jean II */
 876 }
 877
 878 /*
 879  * Function irlap_send_data_secondary_final (self, skb)
 880  *
 881  *    Send I(nformation) frame as secondary with final bit set
 882  *
 883  */
 884 void irlap_send_data_secondary_final(struct irlap_cb *self,
 885                                      struct sk_buff *skb)
 886 {
 887         struct sk_buff *tx_skb = NULL;
 888
 889         ASSERT(self != NULL, return;);
 890         ASSERT(self->magic == LAP_MAGIC, return;);
 891         ASSERT(skb != NULL, return;);
 892
 893         /* Is this reliable or unreliable data? */
 894         if (skb->data[1] == I_FRAME) {
 895
 896                 /*
 897                  *  Insert frame sequence number (Vs) in control field before
 898                  *  inserting into transmit window queue.
 899                  */
 900                 skb->data[1] = I_FRAME | (self->vs << 1);
 901
 902                 /*
 903                  *  Insert frame in store, in case of retransmissions
 904                  *  Increase skb reference count, see irlap_do_event()
 905                  */
 906                 skb_get(skb);
 907                 skb_queue_tail(&self->wx_list, skb);
 908
 909                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 910                 if (tx_skb == NULL) {
 911                         return;
 912                 }
 913
 914                 tx_skb->data[1] |= PF_BIT;
 915
 916                 self->vs = (self->vs + 1) % 8;
 917                 self->ack_required = FALSE;
 918
 919                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 920         } else {
 921                 if (self->ack_required) {
 922                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 923                         irlap_send_rr_frame(self, RSP_FRAME);
 924                         self->ack_required = FALSE;
 925                 } else {
 926                         skb->data[1] |= PF_BIT;
 927                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 928                 }
 929         }
 930
 931         self->window = self->window_size;
 932 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 933         /* We are allowed to transmit a maximum number of bytes again. */
 934         self->bytes_left = self->line_capacity;
 935 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 936
 937         irlap_start_wd_timer(self, self->wd_timeout);
 938 }
 939
 940 /*
 941  * Function irlap_send_data_secondary (self, skb)
 942  *
 943  *    Send I(nformation) frame as secondary without final bit set
 944  *
 945  */
 946 void irlap_send_data_secondary(struct irlap_cb *self, struct sk_buff *skb)
 947 {
 948         struct sk_buff *tx_skb = NULL;
 949
 950         /* Is this reliable or unreliable data? */
 951         if (skb->data[1] == I_FRAME) {
 952
 953                 /*
 954                  *  Insert frame sequence number (Vs) in control field before
 955                  *  inserting into transmit window queue.
 956                  */
 957                 skb->data[1] = I_FRAME | (self->vs << 1);
 958
 959                 /*
 960                  *  Insert frame in store, in case of retransmissions
 961                  *  Increase skb reference count, see irlap_do_event()
 962                  */
 963                 skb_get(skb);
 964                 skb_queue_tail(&self->wx_list, skb);
 965
 966                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 967                 if (tx_skb == NULL) {
 968                         return;
 969                 }
 970
 971                 self->vs = (self->vs + 1) % 8;
 972                 self->ack_required = FALSE;
 973                 self->window -= 1;
 974
 975                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 976         } else {
 977                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 978                 self->window -= 1;
 979         }
 980 }
 981
 982 /*
 983  * Function irlap_resend_rejected_frames (nr)
 984  *
 985  *    Resend frames which has not been acknowledged. Should be safe to
 986  *    traverse the list without locking it since this function will only be
 987  *    called from interrupt context (BH)
 988  */
 989 void irlap_resend_rejected_frames(struct irlap_cb *self, int command)
 990 {
 991         struct sk_buff *tx_skb;
 992         struct sk_buff *skb;
 993         int count;
 994
 995         ASSERT(self != NULL, return;);
 996         ASSERT(self->magic == LAP_MAGIC, return;);
 997
 998         /* Initialize variables */
 999         count = skb_queue_len(&self->wx_list);
1000
1001         /*  Resend unacknowledged frame(s) */
1002         skb = skb_peek(&self->wx_list);
1003         while (skb != NULL) {
1004                 irlap_wait_min_turn_around(self, &self->qos_tx);
1005
1006                 /* We copy the skb to be retransmitted since we will have to
1007                  * modify it. Cloning will confuse packet sniffers
1008                  */
1009                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1010                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1011                 if (!tx_skb) {
1012                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
1013                         return;
1014                 }
1015                 /* Unlink tx_skb from list */
1016                 tx_skb->next = tx_skb->prev = NULL;
1017                 tx_skb->list = NULL;
1018
1019                 /* Clear old Nr field + poll bit */
1020                 tx_skb->data[1] &= 0x0f;
1021
1022                 /*
1023                  *  Set poll bit on the last frame retransmitted
1024                  */
1025                 if (count-- == 1)
1026                         tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1027                 else
1028                         tx_skb->data[1] &= ~PF_BIT; /* Clear p/f bit */
1029
1030                 irlap_send_i_frame(self, tx_skb, command);
1031
1032                 /*
1033                  *  If our skb is the last buffer in the list, then
1034                  *  we are finished, if not, move to the next sk-buffer
1035                  */
1036                 if (skb == skb_peek_tail(&self->wx_list))
1037                         skb = NULL;
1038                 else
1039                         skb = skb->next;
1040         }
1041 #if 0 /* Not yet */
1042         /*
1043          *  We can now fill the window with additional data frames
1044          */
1045         while (skb_queue_len( &self->txq) > 0) {
1046
1047                 IRDA_DEBUG(0, "%s(), sending additional frames!\n", __FUNCTION__);
1048                 if ((skb_queue_len( &self->txq) > 0) &&
1049                     (self->window > 0)) {
1050                         skb = skb_dequeue( &self->txq);
1051                         ASSERT(skb != NULL, return;);
1052
1053                         /*
1054                          *  If send window > 1 then send frame with pf
1055                          *  bit cleared
1056                          */
1057                         if ((self->window > 1) &&
1058                             skb_queue_len(&self->txq) > 0)
1059                         {
1060                                 irlap_send_data_primary(self, skb);
1061                         } else {
1062                                 irlap_send_data_primary_poll(self, skb);
1063                         }
1064                         kfree_skb(skb);
1065                 }
1066         }
1067 #endif
1068 }
1069
1070 void irlap_resend_rejected_frame(struct irlap_cb *self, int command)
1071 {
1072         struct sk_buff *tx_skb;
1073         struct sk_buff *skb;
1074
1075         ASSERT(self != NULL, return;);
1076         ASSERT(self->magic == LAP_MAGIC, return;);
1077
1078         /*  Resend unacknowledged frame(s) */
1079         skb = skb_peek(&self->wx_list);
1080         if (skb != NULL) {
1081                 irlap_wait_min_turn_around(self, &self->qos_tx);
1082
1083                 /* We copy the skb to be retransmitted since we will have to
1084                  * modify it. Cloning will confuse packet sniffers
1085                  */
1086                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1087                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1088                 if (!tx_skb) {
1089                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
1090                         return;
1091                 }
1092                 /* Unlink tx_skb from list */
1093                 tx_skb->next = tx_skb->prev = NULL;
1094                 tx_skb->list = NULL;
1095
1096                 /* Clear old Nr field + poll bit */
1097                 tx_skb->data[1] &= 0x0f;
1098
1099                 /*  Set poll/final bit */
1100                 tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1101
1102                 irlap_send_i_frame(self, tx_skb, command);
1103         }
1104 }
1105
1106 /*
1107  * Function irlap_send_ui_frame (self, skb, command)
1108  *
1109  *    Contruct and transmit an Unnumbered Information (UI) frame
1110  *
1111  */
1112 void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1113                          __u8 caddr, int command)
1114 {
1115         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
1116
1117         ASSERT(self != NULL, return;);
1118         ASSERT(self->magic == LAP_MAGIC, return;);
1119         ASSERT(skb != NULL, return;);
1120
1121         /* Insert connection address */
1122         skb->data[0] = caddr | ((command) ? CMD_FRAME : 0);
1123
1124         irlap_queue_xmit(self, skb);
1125 }
1126
1127 /*
1128  * Function irlap_send_i_frame (skb)
1129  *
1130  *    Contruct and transmit Information (I) frame
1131  */
1132 void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
1133                         int command)
1134 {
1135         /* Insert connection address */
1136         skb->data[0] = self->caddr;
1137         skb->data[0] |= (command) ? CMD_FRAME : 0;
1138
1139         /* Insert next to receive (Vr) */
1140         skb->data[1] |= (self->vr << 5);  /* insert nr */
1141
1142         irlap_queue_xmit(self, skb);
1143 }
1144
1145 /*
1146  * Function irlap_recv_i_frame (skb, frame)
1147  *
1148  *    Receive and parse an I (Information) frame, no harm in making it inline
1149  *    since it's called only from one single place (irlap_driver_rcv).
1150  */
1151 static inline void irlap_recv_i_frame(struct irlap_cb *self,
1152                                       struct sk_buff *skb,
1153                                       struct irlap_info *info, int command)
1154 {
1155         info->nr = skb->data[1] >> 5;          /* Next to receive */
1156         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1157         info->ns = (skb->data[1] >> 1) & 0x07; /* Next to send */
1158
1159         /* Check if this is a command or a response frame */
1160         if (command)
1161                 irlap_do_event(self, RECV_I_CMD, skb, info);
1162         else
1163                 irlap_do_event(self, RECV_I_RSP, skb, info);
1164 }
1165
1166 /*
1167  * Function irlap_recv_ui_frame (self, skb, info)
1168  *
1169  *    Receive and parse an Unnumbered Information (UI) frame
1170  *
1171  */
1172 static void irlap_recv_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1173                                 struct irlap_info *info)
1174 {
1175         IRDA_DEBUG( 4, "%s()\n", __FUNCTION__);
1176
1177         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1178
1179         irlap_do_event(self, RECV_UI_FRAME, skb, info);
1180 }
1181
1182 /*
1183  * Function irlap_recv_frmr_frame (skb, frame)
1184  *
1185  *    Received Frame Reject response.
1186  *
1187  */
1188 static void irlap_recv_frmr_frame(struct irlap_cb *self, struct sk_buff *skb,
1189                                   struct irlap_info *info)
1190 {
1191         __u8 *frame;
1192         int w, x, y, z;
1193
1194         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
1195
1196         ASSERT(self != NULL, return;);
1197         ASSERT(self->magic == LAP_MAGIC, return;);
1198         ASSERT(skb != NULL, return;);
1199         ASSERT(info != NULL, return;);
1200
1201         if (!pskb_may_pull(skb, 4)) {
1202                 ERROR("%s: frame to short!\n", __FUNCTION__);
1203                 return;
1204         }
1205
1206         frame = skb->data;
1207
1208         info->nr = frame[2] >> 5;          /* Next to receive */
1209         info->pf = frame[2] & PF_BIT;      /* Final bit */
1210         info->ns = (frame[2] >> 1) & 0x07; /* Next to send */
1211
1212         w = frame[3] & 0x01;
1213         x = frame[3] & 0x02;
1214         y = frame[3] & 0x04;
1215         z = frame[3] & 0x08;
1216
1217         if (w) {
1218                 IRDA_DEBUG(0, "Rejected control field is undefined or not "
1219                       "implemented.\n");
1220         }
1221         if (x) {
1222                 IRDA_DEBUG(0, "Rejected control field was invalid because it "
1223                       "contained a non permitted I field.\n");
1224         }
1225         if (y) {
1226                 IRDA_DEBUG(0, "Received I field exceeded the maximum negotiated "
1227                       "for the existing connection or exceeded the maximum "
1228                       "this station supports if no connection exists.\n");
1229         }
1230         if (z) {
1231                 IRDA_DEBUG(0, "Rejected control field control field contained an "
1232                       "invalid Nr count.\n");
1233         }
1234         irlap_do_event(self, RECV_FRMR_RSP, skb, info);
1235 }
1236
1237 /*
1238  * Function irlap_send_test_frame (self, daddr)
1239  *
1240  *    Send a test frame response
1241  *
1242  */
1243 void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr,
1244                            struct sk_buff *cmd)
1245 {
1246         struct sk_buff *tx_skb;
1247         struct test_frame *frame;
1248         __u8 *info;
1249
1250         tx_skb = dev_alloc_skb(cmd->len+sizeof(struct test_frame));
1251         if (!tx_skb)
1252                 return;
1253
1254         /* Broadcast frames must include saddr and daddr fields */
1255         if (caddr == CBROADCAST) {
1256                 frame = (struct test_frame *)
1257                         skb_put(tx_skb, sizeof(struct test_frame));
1258
1259                 /* Insert the swapped addresses */
1260                 frame->saddr = cpu_to_le32(self->saddr);
1261                 frame->daddr = cpu_to_le32(daddr);
1262         } else
1263                 frame = (struct test_frame *) skb_put(tx_skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);
1264
1265         frame->caddr = caddr;
1266         frame->control = TEST_RSP | PF_BIT;
1267
1268         /* Copy info */
1269         info = skb_put(tx_skb, cmd->len);
1270         memcpy(info, cmd->data, cmd->len);
1271
1272         /* Return to sender */
1273         irlap_wait_min_turn_around(self, &self->qos_tx);
1274         irlap_queue_xmit(self, tx_skb);
1275 }
1276
1277 /*
1278  * Function irlap_recv_test_frame (self, skb)
1279  *
1280  *    Receive a test frame
1281  *
1282  */
1283 static void irlap_recv_test_frame(struct irlap_cb *self, struct sk_buff *skb,
1284                                   struct irlap_info *info, int command)
1285 {
1286         struct test_frame *frame;
1287
1288         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
1289
1290         if (!pskb_may_pull(skb, sizeof(*frame))) {
1291                 ERROR("%s: frame to short!\n", __FUNCTION__);
1292                 return;
1293         }
1294         frame = (struct test_frame *) skb->data;
1295
1296         /* Broadcast frames must carry saddr and daddr fields */
1297         if (info->caddr == CBROADCAST) {
1298                 if (skb->len < sizeof(struct test_frame)) {
1299                         IRDA_DEBUG(0, "%s() test frame to short!\n",
1300                                    __FUNCTION__);
1301                         return;
1302                 }
1303
1304                 /* Read and swap addresses */
1305                 info->daddr = le32_to_cpu(frame->saddr);
1306                 info->saddr = le32_to_cpu(frame->daddr);
1307
1308                 /* Make sure frame is addressed to us */
1309                 if ((info->saddr != self->saddr) &&
1310                     (info->saddr != BROADCAST)) {
1311                         return;
1312                 }
1313         }
1314
1315         if (command)
1316                 irlap_do_event(self, RECV_TEST_CMD, skb, info);
1317         else
1318                 irlap_do_event(self, RECV_TEST_RSP, skb, info);
1319 }
1320
1321 /*
1322  * Function irlap_driver_rcv (skb, netdev, ptype)
1323  *
1324  *    Called when a frame is received. Dispatches the right receive function
1325  *    for processing of the frame.
1326  *
1327  * Note on skb management :
1328  * After calling the higher layers of the IrDA stack, we always
1329  * kfree() the skb, which drop the reference count (and potentially
1330  * destroy it).
1331  * If a higher layer of the stack want to keep the skb around (to put
1332  * in a queue or pass it to the higher layer), it will need to use
1333  * skb_get() to keep a reference on it. This is usually done at the
1334  * LMP level in irlmp.c.
1335  * Jean II
1336  */
1337 int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,
1338                      struct packet_type *ptype)
1339 {
1340         struct irlap_info info;
1341         struct irlap_cb *self;
1342         int command;
1343         __u8 control;
1344
1345         /* FIXME: should we get our own field? */
1346         self = (struct irlap_cb *) dev->atalk_ptr;
1347
1348         /* If the net device is down, then IrLAP is gone! */
1349         if (!self || self->magic != LAP_MAGIC) {
1350                 dev_kfree_skb(skb);
1351                 return -1;
1352         }
1353
1354         /* We are no longer an "old" protocol, so we need to handle
1355          * share and non linear skbs. This should never happen, so
1356          * we don't need to be clever about it. Jean II */
1357         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
1358                 ERROR("%s: can't clone shared skb!\n", __FUNCTION__);
1359                 dev_kfree_skb(skb);
1360                 return -1;
1361         }
1362
1363         /* Check if frame is large enough for parsing */
1364         if (!pskb_may_pull(skb, 2)) {
1365                 ERROR("%s: frame to short!\n", __FUNCTION__);
1366                 dev_kfree_skb(skb);
1367                 return -1;
1368         }
1369
1370         command    = skb->data[0] & CMD_FRAME;
1371         info.caddr = skb->data[0] & CBROADCAST;
1372
1373         info.pf      = skb->data[1] &  PF_BIT;
1374         info.control = skb->data[1] & ~PF_BIT; /* Mask away poll/final bit */
1375
1376         control = info.control;
1377
1378         /*  First we check if this frame has a valid connection address */
1379         if ((info.caddr != self->caddr) && (info.caddr != CBROADCAST)) {
1380                 IRDA_DEBUG(0, "%s(), wrong connection address!\n",
1381                            __FUNCTION__);
1382                 goto out;
1383         }
1384         /*
1385          *  Optimize for the common case and check if the frame is an
1386          *  I(nformation) frame. Only I-frames have bit 0 set to 0
1387          */
1388         if (~control & 0x01) {
1389                 irlap_recv_i_frame(self, skb, &info, command);
1390                 goto out;
1391         }
1392         /*
1393          *  We now check is the frame is an S(upervisory) frame. Only
1394          *  S-frames have bit 0 set to 1 and bit 1 set to 0
1395          */
1396         if (~control & 0x02) {
1397                 /*
1398                  *  Received S(upervisory) frame, check which frame type it is
1399                  *  only the first nibble is of interest
1400                  */
1401                 switch (control & 0x0f) {
1402                 case RR:
1403                         irlap_recv_rr_frame(self, skb, &info, command);
1404                         break;
1405                 case RNR:
1406                         irlap_recv_rnr_frame(self, skb, &info, command);
1407                         break;
1408                 case REJ:
1409                         irlap_recv_rej_frame(self, skb, &info, command);
1410                         break;
1411                 case SREJ:
1412                         irlap_recv_srej_frame(self, skb, &info, command);
1413                         break;
1414                 default:
1415                         WARNING("%s: Unknown S-frame %02x received!\n",
1416                                 __FUNCTION__, info.control);
1417                         break;
1418                 }
1419                 goto out;
1420         }
1421         /*
1422          *  This must be a C(ontrol) frame
1423          */
1424         switch (control) {
1425         case XID_RSP:
1426                 irlap_recv_discovery_xid_rsp(self, skb, &info);
1427                 break;
1428         case XID_CMD:
1429                 irlap_recv_discovery_xid_cmd(self, skb, &info);
1430                 break;
1431         case SNRM_CMD:
1432                 irlap_recv_snrm_cmd(self, skb, &info);
1433                 break;
1434         case DM_RSP:
1435                 irlap_do_event(self, RECV_DM_RSP, skb, &info);
1436                 break;
1437         case DISC_CMD: /* And RD_RSP since they have the same value */
1438                 irlap_recv_disc_frame(self, skb, &info, command);
1439                 break;
1440         case TEST_CMD:
1441                 irlap_recv_test_frame(self, skb, &info, command);
1442                 break;
1443         case UA_RSP:
1444                 irlap_recv_ua_frame(self, skb, &info);
1445                 break;
1446         case FRMR_RSP:
1447                 irlap_recv_frmr_frame(self, skb, &info);
1448                 break;
1449         case UI_FRAME:
1450                 irlap_recv_ui_frame(self, skb, &info);
1451                 break;
1452         default:
1453                 WARNING("%s: Unknown frame %02x received!\n",
1454                                 __FUNCTION__, info.control);
1455                 break;
1456         }
1457 out:
1458         /* Always drop our reference on the skb */
1459         dev_kfree_skb(skb);
1460         return 0;
1461 }