SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
  47                                int command);
  48
  49 /*
  50  * Function irlap_insert_info (self, skb)
  51  *
  52  *    Insert minimum turnaround time and speed information into the skb. We
  53  *    need to do this since it's per packet relevant information. Safe to
  54  *    have this function inlined since it's only called from one place
  55  */
  56 static inline void irlap_insert_info(struct irlap_cb *self,
  57                                      struct sk_buff *skb)
  58 {
  59         struct irda_skb_cb *cb = (struct irda_skb_cb *) skb->cb;
  60
  61         /*
  62          * Insert MTT (min. turn time) and speed into skb, so that the
  63          * device driver knows which settings to use
  64          */
  65         cb->magic = LAP_MAGIC;
  66         cb->mtt = self->mtt_required;
  67         cb->next_speed = self->speed;
  68
  69         /* Reset */
  70         self->mtt_required = 0;
  71
  72         /*
  73          * Delay equals negotiated BOFs count, plus the number of BOFs to
  74          * force the negotiated minimum turnaround time
  75          */
  76         cb->xbofs = self->bofs_count;
  77         cb->next_xbofs = self->next_bofs;
  78         cb->xbofs_delay = self->xbofs_delay;
  79
  80         /* Reset XBOF's delay (used only for getting min turn time) */
  81         self->xbofs_delay = 0;
  82         /* Put the correct xbofs value for the next packet */
  83         self->bofs_count = self->next_bofs;
  84 }
  85
  86 /*
  87  * Function irlap_queue_xmit (self, skb)
  88  *
  89  *    A little wrapper for dev_queue_xmit, so we can insert some common
  90  *    code into it.
  91  */
  92 void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb)
  93 {
  94         /* Some common init stuff */
  95         skb->dev = self->netdev;
  96         skb_reset_mac_header(skb);
  97         skb_reset_network_header(skb);
  98         skb_reset_transport_header(skb);
  99         skb->protocol = htons(ETH_P_IRDA);
 100         skb->priority = TC_PRIO_BESTEFFORT;
 101
 102         irlap_insert_info(self, skb);
 103
 104         dev_queue_xmit(skb);
 105 }
 106
 107 /*
 108  * Function irlap_send_snrm_cmd (void)
 109  *
 110  *    Transmits a connect SNRM command frame
 111  */
 112 void irlap_send_snrm_frame(struct irlap_cb *self, struct qos_info *qos)
 113 {
 114         struct sk_buff *tx_skb;
 115         struct snrm_frame *frame;
 116         int ret;
 117
 118         IRDA_ASSERT(self != NULL, return;);
 119         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 120
 121         /* Allocate frame */
 122         tx_skb = alloc_skb(sizeof(struct snrm_frame) +
 123                            IRLAP_NEGOCIATION_PARAMS_LEN,
 124                            GFP_ATOMIC);
 125         if (!tx_skb)
 126                 return;
 127
 128         frame = (struct snrm_frame *) skb_put(tx_skb, 2);
 129
 130         /* Insert connection address field */
 131         if (qos)
 132                 frame->caddr = CMD_FRAME | CBROADCAST;
 133         else
 134                 frame->caddr = CMD_FRAME | self->caddr;
 135
 136         /* Insert control field */
 137         frame->control = SNRM_CMD | PF_BIT;
 138
 139         /*
 140          *  If we are establishing a connection then insert QoS paramerters
 141          */
 142         if (qos) {
 143                 skb_put(tx_skb, 9); /* 25 left */
 144                 frame->saddr = cpu_to_le32(self->saddr);
 145                 frame->daddr = cpu_to_le32(self->daddr);
 146
 147                 frame->ncaddr = self->caddr;
 148
 149                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 150                 if (ret < 0) {
 151                         dev_kfree_skb(tx_skb);
 152                         return;
 153                 }
 154         }
 155         irlap_queue_xmit(self, tx_skb);
 156 }
 157
 158 /*
 159  * Function irlap_recv_snrm_cmd (skb, info)
 160  *
 161  *    Received SNRM (Set Normal Response Mode) command frame
 162  *
 163  */
 164 static void irlap_recv_snrm_cmd(struct irlap_cb *self, struct sk_buff *skb,
 165                                 struct irlap_info *info)
 166 {
 167         struct snrm_frame *frame;
 168
 169         if (pskb_may_pull(skb,sizeof(struct snrm_frame))) {
 170                 frame = (struct snrm_frame *) skb->data;
 171
 172                 /* Copy the new connection address ignoring the C/R bit */
 173                 info->caddr = frame->ncaddr & 0xFE;
 174
 175                 /* Check if the new connection address is valid */
 176                 if ((info->caddr == 0x00) || (info->caddr == 0xfe)) {
 177                         IRDA_DEBUG(3, "%s(), invalid connection address!\n",
 178                                    __FUNCTION__);
 179                         return;
 180                 }
 181
 182                 /* Copy peer device address */
 183                 info->daddr = le32_to_cpu(frame->saddr);
 184                 info->saddr = le32_to_cpu(frame->daddr);
 185
 186                 /* Only accept if addressed directly to us */
 187                 if (info->saddr != self->saddr) {
 188                         IRDA_DEBUG(2, "%s(), not addressed to us!\n",
 189                                    __FUNCTION__);
 190                         return;
 191                 }
 192                 irlap_do_event(self, RECV_SNRM_CMD, skb, info);
 193         } else {
 194                 /* Signal that this SNRM frame does not contain and I-field */
 195                 irlap_do_event(self, RECV_SNRM_CMD, skb, NULL);
 196         }
 197 }
 198
 199 /*
 200  * Function irlap_send_ua_response_frame (qos)
 201  *
 202  *    Send UA (Unnumbered Acknowledgement) frame
 203  *
 204  */
 205 void irlap_send_ua_response_frame(struct irlap_cb *self, struct qos_info *qos)
 206 {
 207         struct sk_buff *tx_skb;
 208         struct ua_frame *frame;
 209         int ret;
 210
 211         IRDA_DEBUG(2, "%s() <%ld>\n", __FUNCTION__, jiffies);
 212
 213         IRDA_ASSERT(self != NULL, return;);
 214         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 215
 216         /* Allocate frame */
 217         tx_skb = alloc_skb(sizeof(struct ua_frame) +
 218                            IRLAP_NEGOCIATION_PARAMS_LEN,
 219                            GFP_ATOMIC);
 220         if (!tx_skb)
 221                 return;
 222
 223         frame = (struct ua_frame *) skb_put(tx_skb, 10);
 224
 225         /* Build UA response */
 226         frame->caddr = self->caddr;
 227         frame->control = UA_RSP | PF_BIT;
 228
 229         frame->saddr = cpu_to_le32(self->saddr);
 230         frame->daddr = cpu_to_le32(self->daddr);
 231
 232         /* Should we send QoS negotiation parameters? */
 233         if (qos) {
 234                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 235                 if (ret < 0) {
 236                         dev_kfree_skb(tx_skb);
 237                         return;
 238                 }
 239         }
 240
 241         irlap_queue_xmit(self, tx_skb);
 242 }
 243
 244
 245 /*
 246  * Function irlap_send_dm_frame (void)
 247  *
 248  *    Send disconnected mode (DM) frame
 249  *
 250  */
 251 void irlap_send_dm_frame( struct irlap_cb *self)
 252 {
 253         struct sk_buff *tx_skb = NULL;
 254         struct dm_frame *frame;
 255
 256         IRDA_ASSERT(self != NULL, return;);
 257         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 258
 259         tx_skb = alloc_skb(sizeof(struct dm_frame), GFP_ATOMIC);
 260         if (!tx_skb)
 261                 return;
 262
 263         frame = (struct dm_frame *)skb_put(tx_skb, 2);
 264
 265         if (self->state == LAP_NDM)
 266                 frame->caddr = CBROADCAST;
 267         else
 268                 frame->caddr = self->caddr;
 269
 270         frame->control = DM_RSP | PF_BIT;
 271
 272         irlap_queue_xmit(self, tx_skb);
 273 }
 274
 275 /*
 276  * Function irlap_send_disc_frame (void)
 277  *
 278  *    Send disconnect (DISC) frame
 279  *
 280  */
 281 void irlap_send_disc_frame(struct irlap_cb *self)
 282 {
 283         struct sk_buff *tx_skb = NULL;
 284         struct disc_frame *frame;
 285
 286         IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
 287
 288         IRDA_ASSERT(self != NULL, return;);
 289         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 290
 291         tx_skb = alloc_skb(sizeof(struct disc_frame), GFP_ATOMIC);
 292         if (!tx_skb)
 293                 return;
 294
 295         frame = (struct disc_frame *)skb_put(tx_skb, 2);
 296
 297         frame->caddr = self->caddr | CMD_FRAME;
 298         frame->control = DISC_CMD | PF_BIT;
 299
 300         irlap_queue_xmit(self, tx_skb);
 301 }
 302
 303 /*
 304  * Function irlap_send_discovery_xid_frame (S, s, command)
 305  *
 306  *    Build and transmit a XID (eXchange station IDentifier) discovery
 307  *    frame.
 308  */
 309 void irlap_send_discovery_xid_frame(struct irlap_cb *self, int S, __u8 s,
 310                                     __u8 command, discovery_t *discovery)
 311 {
 312         struct sk_buff *tx_skb = NULL;
 313         struct xid_frame *frame;
 314         __u32 bcast = BROADCAST;
 315         __u8 *info;
 316
 317         IRDA_DEBUG(4, "%s(), s=%d, S=%d, command=%d\n", __FUNCTION__,
 318                    s, S, command);
 319
 320         IRDA_ASSERT(self != NULL, return;);
 321         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 322         IRDA_ASSERT(discovery != NULL, return;);
 323
 324         tx_skb = alloc_skb(sizeof(struct xid_frame) + IRLAP_DISCOVERY_INFO_LEN,
 325                            GFP_ATOMIC);
 326         if (!tx_skb)
 327                 return;
 328
 329         skb_put(tx_skb, 14);
 330         frame = (struct xid_frame *) tx_skb->data;
 331
 332         if (command) {
 333                 frame->caddr = CBROADCAST | CMD_FRAME;
 334                 frame->control =  XID_CMD | PF_BIT;
 335         } else {
 336                 frame->caddr = CBROADCAST;
 337                 frame->control =  XID_RSP | PF_BIT;
 338         }
 339         frame->ident = XID_FORMAT;
 340
 341         frame->saddr = cpu_to_le32(self->saddr);
 342
 343         if (command)
 344                 frame->daddr = cpu_to_le32(bcast);
 345         else
 346                 frame->daddr = cpu_to_le32(discovery->data.daddr);
 347
 348         switch (S) {
 349         case 1:
 350                 frame->flags = 0x00;
 351                 break;
 352         case 6:
 353                 frame->flags = 0x01;
 354                 break;
 355         case 8:
 356                 frame->flags = 0x02;
 357                 break;
 358         case 16:
 359                 frame->flags = 0x03;
 360                 break;
 361         default:
 362                 frame->flags = 0x02;
 363                 break;
 364         }
 365
 366         frame->slotnr = s;
 367         frame->version = 0x00;
 368
 369         /*
 370          *  Provide info for final slot only in commands, and for all
 371          *  responses. Send the second byte of the hint only if the
 372          *  EXTENSION bit is set in the first byte.
 373          */
 374         if (!command || (frame->slotnr == 0xff)) {
 375                 int len;
 376
 377                 if (discovery->data.hints[0] & HINT_EXTENSION) {
 378                         info = skb_put(tx_skb, 2);
 379                         info[0] = discovery->data.hints[0];
 380                         info[1] = discovery->data.hints[1];
 381                 } else {
 382                         info = skb_put(tx_skb, 1);
 383                         info[0] = discovery->data.hints[0];
 384                 }
 385                 info = skb_put(tx_skb, 1);
 386                 info[0] = discovery->data.charset;
 387
 388                 len = IRDA_MIN(discovery->name_len, skb_tailroom(tx_skb));
 389                 info = skb_put(tx_skb, len);
 390                 memcpy(info, discovery->data.info, len);
 391         }
 392         irlap_queue_xmit(self, tx_skb);
 393 }
 394
 395 /*
 396  * Function irlap_recv_discovery_xid_rsp (skb, info)
 397  *
 398  *    Received a XID discovery response
 399  *
 400  */
 401 static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
 402                                          struct sk_buff *skb,
 403                                          struct irlap_info *info)
 404 {
 405         struct xid_frame *xid;
 406         discovery_t *discovery = NULL;
 407         __u8 *discovery_info;
 408         char *text;
 409
 410         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 411
 412         IRDA_ASSERT(self != NULL, return;);
 413         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 414
 415         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 416                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
 417                 return;
 418         }
 419
 420         xid = (struct xid_frame *) skb->data;
 421
 422         info->daddr = le32_to_cpu(xid->saddr);
 423         info->saddr = le32_to_cpu(xid->daddr);
 424
 425         /* Make sure frame is addressed to us */
 426         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 427                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 428                            __FUNCTION__);
 429                 return;
 430         }
 431
 432         if ((discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {
 433                 IRDA_WARNING("%s: kmalloc failed!\n", __FUNCTION__);
 434                 return;
 435         }
 436
 437         discovery->data.daddr = info->daddr;
 438         discovery->data.saddr = self->saddr;
 439         discovery->timestamp = jiffies;
 440
 441         IRDA_DEBUG(4, "%s(), daddr=%08x\n", __FUNCTION__,
 442                    discovery->data.daddr);
 443
 444         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 445
 446         /* Get info returned from peer */
 447         discovery->data.hints[0] = discovery_info[0];
 448         if (discovery_info[0] & HINT_EXTENSION) {
 449                 IRDA_DEBUG(4, "EXTENSION\n");
 450                 discovery->data.hints[1] = discovery_info[1];
 451                 discovery->data.charset = discovery_info[2];
 452                 text = (char *) &discovery_info[3];
 453         } else {
 454                 discovery->data.hints[1] = 0;
 455                 discovery->data.charset = discovery_info[1];
 456                 text = (char *) &discovery_info[2];
 457         }
 458         /*
 459          *  Terminate info string, should be safe since this is where the
 460          *  FCS bytes resides.
 461          */
 462         skb->data[skb->len] = '\0';
 463         strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 464         discovery->name_len = strlen(discovery->data.info);
 465
 466         info->discovery = discovery;
 467
 468         irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
 469 }
 470
 471 /*
 472  * Function irlap_recv_discovery_xid_cmd (skb, info)
 473  *
 474  *    Received a XID discovery command
 475  *
 476  */
 477 static void irlap_recv_discovery_xid_cmd(struct irlap_cb *self,
 478                                          struct sk_buff *skb,
 479                                          struct irlap_info *info)
 480 {
 481         struct xid_frame *xid;
 482         discovery_t *discovery = NULL;
 483         __u8 *discovery_info;
 484         char *text;
 485
 486         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 487                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
 488                 return;
 489         }
 490
 491         xid = (struct xid_frame *) skb->data;
 492
 493         info->daddr = le32_to_cpu(xid->saddr);
 494         info->saddr = le32_to_cpu(xid->daddr);
 495
 496         /* Make sure frame is addressed to us */
 497         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 498                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 499                            __FUNCTION__);
 500                 return;
 501         }
 502
 503         switch (xid->flags & 0x03) {
 504         case 0x00:
 505                 info->S = 1;
 506                 break;
 507         case 0x01:
 508                 info->S = 6;
 509                 break;
 510         case 0x02:
 511                 info->S = 8;
 512                 break;
 513         case 0x03:
 514                 info->S = 16;
 515                 break;
 516         default:
 517                 /* Error!! */
 518                 return;
 519         }
 520         info->s = xid->slotnr;
 521
 522         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 523
 524         /*
 525          *  Check if last frame
 526          */
 527         if (info->s == 0xff) {
 528                 /* Check if things are sane at this point... */
 529                 if((discovery_info == NULL) ||
 530                    !pskb_may_pull(skb, 3)) {
 531                         IRDA_ERROR("%s: discovery frame too short!\n",
 532                                    __FUNCTION__);
 533                         return;
 534                 }
 535
 536                 /*
 537                  *  We now have some discovery info to deliver!
 538                  */
 539                 discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC);
 540                 if (!discovery) {
 541                         IRDA_WARNING("%s: unable to malloc!\n", __FUNCTION__);
 542                         return;
 543                 }
 544
 545                 discovery->data.daddr = info->daddr;
 546                 discovery->data.saddr = self->saddr;
 547                 discovery->timestamp = jiffies;
 548
 549                 discovery->data.hints[0] = discovery_info[0];
 550                 if (discovery_info[0] & HINT_EXTENSION) {
 551                         discovery->data.hints[1] = discovery_info[1];
 552                         discovery->data.charset = discovery_info[2];
 553                         text = (char *) &discovery_info[3];
 554                 } else {
 555                         discovery->data.hints[1] = 0;
 556                         discovery->data.charset = discovery_info[1];
 557                         text = (char *) &discovery_info[2];
 558                 }
 559                 /*
 560                  *  Terminate string, should be safe since this is where the
 561                  *  FCS bytes resides.
 562                  */
 563                 skb->data[skb->len] = '\0';
 564                 strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 565                 discovery->name_len = strlen(discovery->data.info);
 566
 567                 info->discovery = discovery;
 568         } else
 569                 info->discovery = NULL;
 570
 571         irlap_do_event(self, RECV_DISCOVERY_XID_CMD, skb, info);
 572 }
 573
 574 /*
 575  * Function irlap_send_rr_frame (self, command)
 576  *
 577  *    Build and transmit RR (Receive Ready) frame. Notice that it is currently
 578  *    only possible to send RR frames with the poll bit set.
 579  */
 580 void irlap_send_rr_frame(struct irlap_cb *self, int command)
 581 {
 582         struct sk_buff *tx_skb;
 583         struct rr_frame *frame;
 584
 585         tx_skb = alloc_skb(sizeof(struct rr_frame), GFP_ATOMIC);
 586         if (!tx_skb)
 587                 return;
 588
 589         frame = (struct rr_frame *)skb_put(tx_skb, 2);
 590
 591         frame->caddr = self->caddr;
 592         frame->caddr |= (command) ? CMD_FRAME : 0;
 593
 594         frame->control = RR | PF_BIT | (self->vr << 5);
 595
 596         irlap_queue_xmit(self, tx_skb);
 597 }
 598
 599 /*
 600  * Function irlap_send_rd_frame (self)
 601  *
 602  *    Request disconnect. Used by a secondary station to request the
 603  *    disconnection of the link.
 604  */
 605 void irlap_send_rd_frame(struct irlap_cb *self)
 606 {
 607         struct sk_buff *tx_skb;
 608         struct rd_frame *frame;
 609
 610         tx_skb = alloc_skb(sizeof(struct rd_frame), GFP_ATOMIC);
 611         if (!tx_skb)
 612                 return;
 613
 614         frame = (struct rd_frame *)skb_put(tx_skb, 2);
 615
 616         frame->caddr = self->caddr;
 617         frame->caddr = RD_RSP | PF_BIT;
 618
 619         irlap_queue_xmit(self, tx_skb);
 620 }
 621
 622 /*
 623  * Function irlap_recv_rr_frame (skb, info)
 624  *
 625  *    Received RR (Receive Ready) frame from peer station, no harm in
 626  *    making it inline since its called only from one single place
 627  *    (irlap_driver_rcv).
 628  */
 629 static inline void irlap_recv_rr_frame(struct irlap_cb *self,
 630                                        struct sk_buff *skb,
 631                                        struct irlap_info *info, int command)
 632 {
 633         info->nr = skb->data[1] >> 5;
 634
 635         /* Check if this is a command or a response frame */
 636         if (command)
 637                 irlap_do_event(self, RECV_RR_CMD, skb, info);
 638         else
 639                 irlap_do_event(self, RECV_RR_RSP, skb, info);
 640 }
 641
 642 /*
 643  * Function irlap_recv_rnr_frame (self, skb, info)
 644  *
 645  *    Received RNR (Receive Not Ready) frame from peer station
 646  *
 647  */
 648 static void irlap_recv_rnr_frame(struct irlap_cb *self, struct sk_buff *skb,
 649                                  struct irlap_info *info, int command)
 650 {
 651         info->nr = skb->data[1] >> 5;
 652
 653         IRDA_DEBUG(4, "%s(), nr=%d, %ld\n", __FUNCTION__, info->nr, jiffies);
 654
 655         if (command)
 656                 irlap_do_event(self, RECV_RNR_CMD, skb, info);
 657         else
 658                 irlap_do_event(self, RECV_RNR_RSP, skb, info);
 659 }
 660
 661 static void irlap_recv_rej_frame(struct irlap_cb *self, struct sk_buff *skb,
 662                                  struct irlap_info *info, int command)
 663 {
 664         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 665
 666         info->nr = skb->data[1] >> 5;
 667
 668         /* Check if this is a command or a response frame */
 669         if (command)
 670                 irlap_do_event(self, RECV_REJ_CMD, skb, info);
 671         else
 672                 irlap_do_event(self, RECV_REJ_RSP, skb, info);
 673 }
 674
 675 static void irlap_recv_srej_frame(struct irlap_cb *self, struct sk_buff *skb,
 676                                   struct irlap_info *info, int command)
 677 {
 678         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 679
 680         info->nr = skb->data[1] >> 5;
 681
 682         /* Check if this is a command or a response frame */
 683         if (command)
 684                 irlap_do_event(self, RECV_SREJ_CMD, skb, info);
 685         else
 686                 irlap_do_event(self, RECV_SREJ_RSP, skb, info);
 687 }
 688
 689 static void irlap_recv_disc_frame(struct irlap_cb *self, struct sk_buff *skb,
 690                                   struct irlap_info *info, int command)
 691 {
 692         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 693
 694         /* Check if this is a command or a response frame */
 695         if (command)
 696                 irlap_do_event(self, RECV_DISC_CMD, skb, info);
 697         else
 698                 irlap_do_event(self, RECV_RD_RSP, skb, info);
 699 }
 700
 701 /*
 702  * Function irlap_recv_ua_frame (skb, frame)
 703  *
 704  *    Received UA (Unnumbered Acknowledgement) frame
 705  *
 706  */
 707 static inline void irlap_recv_ua_frame(struct irlap_cb *self,
 708                                        struct sk_buff *skb,
 709                                        struct irlap_info *info)
 710 {
 711         irlap_do_event(self, RECV_UA_RSP, skb, info);
 712 }
 713
 714 /*
 715  * Function irlap_send_data_primary(self, skb)
 716  *
 717  *    Send I-frames as the primary station but without the poll bit set
 718  *
 719  */
 720 void irlap_send_data_primary(struct irlap_cb *self, struct sk_buff *skb)
 721 {
 722         struct sk_buff *tx_skb;
 723
 724         if (skb->data[1] == I_FRAME) {
 725
 726                 /*
 727                  *  Insert frame sequence number (Vs) in control field before
 728                  *  inserting into transmit window queue.
 729                  */
 730                 skb->data[1] = I_FRAME | (self->vs << 1);
 731
 732                 /*
 733                  *  Insert frame in store, in case of retransmissions
 734                  *  Increase skb reference count, see irlap_do_event()
 735                  */
 736                 skb_get(skb);
 737                 skb_queue_tail(&self->wx_list, skb);
 738
 739                 /* Copy buffer */
 740                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 741                 if (tx_skb == NULL) {
 742                         return;
 743                 }
 744
 745                 self->vs = (self->vs + 1) % 8;
 746                 self->ack_required = FALSE;
 747                 self->window -= 1;
 748
 749                 irlap_send_i_frame( self, tx_skb, CMD_FRAME);
 750         } else {
 751                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 752                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 753                 self->window -= 1;
 754         }
 755 }
 756 /*
 757  * Function irlap_send_data_primary_poll (self, skb)
 758  *
 759  *    Send I(nformation) frame as primary with poll bit set
 760  */
 761 void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
 762 {
 763         struct sk_buff *tx_skb;
 764         int transmission_time;
 765
 766         /* Stop P timer */
 767         del_timer(&self->poll_timer);
 768
 769         /* Is this reliable or unreliable data? */
 770         if (skb->data[1] == I_FRAME) {
 771
 772                 /*
 773                  *  Insert frame sequence number (Vs) in control field before
 774                  *  inserting into transmit window queue.
 775                  */
 776                 skb->data[1] = I_FRAME | (self->vs << 1);
 777
 778                 /*
 779                  *  Insert frame in store, in case of retransmissions
 780                  *  Increase skb reference count, see irlap_do_event()
 781                  */
 782                 skb_get(skb);
 783                 skb_queue_tail(&self->wx_list, skb);
 784
 785                 /* Copy buffer */
 786                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 787                 if (tx_skb == NULL) {
 788                         return;
 789                 }
 790
 791                 /*
 792                  *  Set poll bit if necessary. We do this to the copied
 793                  *  skb, since retransmitted need to set or clear the poll
 794                  *  bit depending on when they are sent.
 795                  */
 796                 tx_skb->data[1] |= PF_BIT;
 797
 798                 self->vs = (self->vs + 1) % 8;
 799                 self->ack_required = FALSE;
 800
 801                 irlap_next_state(self, LAP_NRM_P);
 802                 irlap_send_i_frame(self, tx_skb, CMD_FRAME);
 803         } else {
 804                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 805
 806                 if (self->ack_required) {
 807                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 808                         irlap_next_state(self, LAP_NRM_P);
 809                         irlap_send_rr_frame(self, CMD_FRAME);
 810                         self->ack_required = FALSE;
 811                 } else {
 812                         skb->data[1] |= PF_BIT;
 813                         irlap_next_state(self, LAP_NRM_P);
 814                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 815                 }
 816         }
 817
 818         /* How much time we took for transmission of all frames.
 819          * We don't know, so let assume we used the full window. Jean II */
 820         transmission_time = self->final_timeout;
 821
 822         /* Reset parameter so that we can fill next window */
 823         self->window = self->window_size;
 824
 825 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 826         /* Remove what we have not used. Just do a prorata of the
 827          * bytes left in window to window capacity.
 828          * See max_line_capacities[][] in qos.c for details. Jean II */
 829         transmission_time -= (self->final_timeout * self->bytes_left
 830                               / self->line_capacity);
 831         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);
 832
 833         /* We are allowed to transmit a maximum number of bytes again. */
 834         self->bytes_left = self->line_capacity;
 835 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 836
 837         /*
 838          * The network layer has a intermediate buffer between IrLAP
 839          * and the IrDA driver which can contain 8 frames. So, even
 840          * though IrLAP is currently sending the *last* frame of the
 841          * tx-window, the driver most likely has only just started
 842          * sending the *first* frame of the same tx-window.
 843          * I.e. we are always at the very begining of or Tx window.
 844          * Now, we are supposed to set the final timer from the end
 845          * of our tx-window to let the other peer reply. So, we need
 846          * to add extra time to compensate for the fact that we
 847          * are really at the start of tx-window, otherwise the final timer
 848          * might expire before he can answer...
 849          * Jean II
 850          */
 851         irlap_start_final_timer(self, self->final_timeout + transmission_time);
 852
 853         /*
 854          * The clever amongst you might ask why we do this adjustement
 855          * only here, and not in all the other cases in irlap_event.c.
 856          * In all those other case, we only send a very short management
 857          * frame (few bytes), so the adjustement would be lost in the
 858          * noise...
 859          * The exception of course is irlap_resend_rejected_frame().
 860          * Jean II */
 861 }
 862
 863 /*
 864  * Function irlap_send_data_secondary_final (self, skb)
 865  *
 866  *    Send I(nformation) frame as secondary with final bit set
 867  *
 868  */
 869 void irlap_send_data_secondary_final(struct irlap_cb *self,
 870                                      struct sk_buff *skb)
 871 {
 872         struct sk_buff *tx_skb = NULL;
 873
 874         IRDA_ASSERT(self != NULL, return;);
 875         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 876         IRDA_ASSERT(skb != NULL, return;);
 877
 878         /* Is this reliable or unreliable data? */
 879         if (skb->data[1] == I_FRAME) {
 880
 881                 /*
 882                  *  Insert frame sequence number (Vs) in control field before
 883                  *  inserting into transmit window queue.
 884                  */
 885                 skb->data[1] = I_FRAME | (self->vs << 1);
 886
 887                 /*
 888                  *  Insert frame in store, in case of retransmissions
 889                  *  Increase skb reference count, see irlap_do_event()
 890                  */
 891                 skb_get(skb);
 892                 skb_queue_tail(&self->wx_list, skb);
 893
 894                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 895                 if (tx_skb == NULL) {
 896                         return;
 897                 }
 898
 899                 tx_skb->data[1] |= PF_BIT;
 900
 901                 self->vs = (self->vs + 1) % 8;
 902                 self->ack_required = FALSE;
 903
 904                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 905         } else {
 906                 if (self->ack_required) {
 907                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 908                         irlap_send_rr_frame(self, RSP_FRAME);
 909                         self->ack_required = FALSE;
 910                 } else {
 911                         skb->data[1] |= PF_BIT;
 912                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 913                 }
 914         }
 915
 916         self->window = self->window_size;
 917 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 918         /* We are allowed to transmit a maximum number of bytes again. */
 919         self->bytes_left = self->line_capacity;
 920 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 921
 922         irlap_start_wd_timer(self, self->wd_timeout);
 923 }
 924
 925 /*
 926  * Function irlap_send_data_secondary (self, skb)
 927  *
 928  *    Send I(nformation) frame as secondary without final bit set
 929  *
 930  */
 931 void irlap_send_data_secondary(struct irlap_cb *self, struct sk_buff *skb)
 932 {
 933         struct sk_buff *tx_skb = NULL;
 934
 935         /* Is this reliable or unreliable data? */
 936         if (skb->data[1] == I_FRAME) {
 937
 938                 /*
 939                  *  Insert frame sequence number (Vs) in control field before
 940                  *  inserting into transmit window queue.
 941                  */
 942                 skb->data[1] = I_FRAME | (self->vs << 1);
 943
 944                 /*
 945                  *  Insert frame in store, in case of retransmissions
 946                  *  Increase skb reference count, see irlap_do_event()
 947                  */
 948                 skb_get(skb);
 949                 skb_queue_tail(&self->wx_list, skb);
 950
 951                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 952                 if (tx_skb == NULL) {
 953                         return;
 954                 }
 955
 956                 self->vs = (self->vs + 1) % 8;
 957                 self->ack_required = FALSE;
 958                 self->window -= 1;
 959
 960                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 961         } else {
 962                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 963                 self->window -= 1;
 964         }
 965 }
 966
 967 /*
 968  * Function irlap_resend_rejected_frames (nr)
 969  *
 970  *    Resend frames which has not been acknowledged. Should be safe to
 971  *    traverse the list without locking it since this function will only be
 972  *    called from interrupt context (BH)
 973  */
 974 void irlap_resend_rejected_frames(struct irlap_cb *self, int command)
 975 {
 976         struct sk_buff *tx_skb;
 977         struct sk_buff *skb;
 978         int count;
 979
 980         IRDA_ASSERT(self != NULL, return;);
 981         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 982
 983         /* Initialize variables */
 984         count = skb_queue_len(&self->wx_list);
 985
 986         /*  Resend unacknowledged frame(s) */
 987         skb = skb_peek(&self->wx_list);
 988         while (skb != NULL) {
 989                 irlap_wait_min_turn_around(self, &self->qos_tx);
 990
 991                 /* We copy the skb to be retransmitted since we will have to
 992                  * modify it. Cloning will confuse packet sniffers
 993                  */
 994                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
 995                 tx_skb = skb_copy(skb, GFP_ATOMIC);
 996                 if (!tx_skb) {
 997                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
 998                         return;
 999                 }
1000
1001                 /* Clear old Nr field + poll bit */
1002                 tx_skb->data[1] &= 0x0f;
1003
1004                 /*
1005                  *  Set poll bit on the last frame retransmitted
1006                  */
1007                 if (count-- == 1)
1008                         tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1009                 else
1010                         tx_skb->data[1] &= ~PF_BIT; /* Clear p/f bit */
1011
1012                 irlap_send_i_frame(self, tx_skb, command);
1013
1014                 /*
1015                  *  If our skb is the last buffer in the list, then
1016                  *  we are finished, if not, move to the next sk-buffer
1017                  */
1018                 if (skb == skb_peek_tail(&self->wx_list))
1019                         skb = NULL;
1020                 else
1021                         skb = skb->next;
1022         }
1023 #if 0 /* Not yet */
1024         /*
1025          *  We can now fill the window with additional data frames
1026          */
1027         while (!skb_queue_empty(&self->txq)) {
1028
1029                 IRDA_DEBUG(0, "%s(), sending additional frames!\n", __FUNCTION__);
1030                 if (self->window > 0) {
1031                         skb = skb_dequeue( &self->txq);
1032                         IRDA_ASSERT(skb != NULL, return;);
1033
1034                         /*
1035                          *  If send window > 1 then send frame with pf
1036                          *  bit cleared
1037                          */
1038                         if ((self->window > 1) &&
1039                             !skb_queue_empty(&self->txq)) {
1040                                 irlap_send_data_primary(self, skb);
1041                         } else {
1042                                 irlap_send_data_primary_poll(self, skb);
1043                         }
1044                         kfree_skb(skb);
1045                 }
1046         }
1047 #endif
1048 }
1049
1050 void irlap_resend_rejected_frame(struct irlap_cb *self, int command)
1051 {
1052         struct sk_buff *tx_skb;
1053         struct sk_buff *skb;
1054
1055         IRDA_ASSERT(self != NULL, return;);
1056         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1057
1058         /*  Resend unacknowledged frame(s) */
1059         skb = skb_peek(&self->wx_list);
1060         if (skb != NULL) {
1061                 irlap_wait_min_turn_around(self, &self->qos_tx);
1062
1063                 /* We copy the skb to be retransmitted since we will have to
1064                  * modify it. Cloning will confuse packet sniffers
1065                  */
1066                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1067                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1068                 if (!tx_skb) {
1069                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
1070                         return;
1071                 }
1072
1073                 /* Clear old Nr field + poll bit */
1074                 tx_skb->data[1] &= 0x0f;
1075
1076                 /*  Set poll/final bit */
1077                 tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1078
1079                 irlap_send_i_frame(self, tx_skb, command);
1080         }
1081 }
1082
1083 /*
1084  * Function irlap_send_ui_frame (self, skb, command)
1085  *
1086  *    Contruct and transmit an Unnumbered Information (UI) frame
1087  *
1088  */
1089 void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1090                          __u8 caddr, int command)
1091 {
1092         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
1093
1094         IRDA_ASSERT(self != NULL, return;);
1095         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1096         IRDA_ASSERT(skb != NULL, return;);
1097
1098         /* Insert connection address */
1099         skb->data[0] = caddr | ((command) ? CMD_FRAME : 0);
1100
1101         irlap_queue_xmit(self, skb);
1102 }
1103
1104 /*
1105  * Function irlap_send_i_frame (skb)
1106  *
1107  *    Contruct and transmit Information (I) frame
1108  */
1109 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
1110                                int command)
1111 {
1112         /* Insert connection address */
1113         skb->data[0] = self->caddr;
1114         skb->data[0] |= (command) ? CMD_FRAME : 0;
1115
1116         /* Insert next to receive (Vr) */
1117         skb->data[1] |= (self->vr << 5);  /* insert nr */
1118
1119         irlap_queue_xmit(self, skb);
1120 }
1121
1122 /*
1123  * Function irlap_recv_i_frame (skb, frame)
1124  *
1125  *    Receive and parse an I (Information) frame, no harm in making it inline
1126  *    since it's called only from one single place (irlap_driver_rcv).
1127  */
1128 static inline void irlap_recv_i_frame(struct irlap_cb *self,
1129                                       struct sk_buff *skb,
1130                                       struct irlap_info *info, int command)
1131 {
1132         info->nr = skb->data[1] >> 5;          /* Next to receive */
1133         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1134         info->ns = (skb->data[1] >> 1) & 0x07; /* Next to send */
1135
1136         /* Check if this is a command or a response frame */
1137         if (command)
1138                 irlap_do_event(self, RECV_I_CMD, skb, info);
1139         else
1140                 irlap_do_event(self, RECV_I_RSP, skb, info);
1141 }
1142
1143 /*
1144  * Function irlap_recv_ui_frame (self, skb, info)
1145  *
1146  *    Receive and parse an Unnumbered Information (UI) frame
1147  *
1148  */
1149 static void irlap_recv_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1150                                 struct irlap_info *info)
1151 {
1152         IRDA_DEBUG( 4, "%s()\n", __FUNCTION__);
1153
1154         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1155
1156         irlap_do_event(self, RECV_UI_FRAME, skb, info);
1157 }
1158
1159 /*
1160  * Function irlap_recv_frmr_frame (skb, frame)
1161  *
1162  *    Received Frame Reject response.
1163  *
1164  */
1165 static void irlap_recv_frmr_frame(struct irlap_cb *self, struct sk_buff *skb,
1166                                   struct irlap_info *info)
1167 {
1168         __u8 *frame;
1169         int w, x, y, z;
1170
1171         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
1172
1173         IRDA_ASSERT(self != NULL, return;);
1174         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1175         IRDA_ASSERT(skb != NULL, return;);
1176         IRDA_ASSERT(info != NULL, return;);
1177
1178         if (!pskb_may_pull(skb, 4)) {
1179                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
1180                 return;
1181         }
1182
1183         frame = skb->data;
1184
1185         info->nr = frame[2] >> 5;          /* Next to receive */
1186         info->pf = frame[2] & PF_BIT;      /* Final bit */
1187         info->ns = (frame[2] >> 1) & 0x07; /* Next to send */
1188
1189         w = frame[3] & 0x01;
1190         x = frame[3] & 0x02;
1191         y = frame[3] & 0x04;
1192         z = frame[3] & 0x08;
1193
1194         if (w) {
1195                 IRDA_DEBUG(0, "Rejected control field is undefined or not "
1196                       "implemented.\n");
1197         }
1198         if (x) {
1199                 IRDA_DEBUG(0, "Rejected control field was invalid because it "
1200                       "contained a non permitted I field.\n");
1201         }
1202         if (y) {
1203                 IRDA_DEBUG(0, "Received I field exceeded the maximum negotiated "
1204                       "for the existing connection or exceeded the maximum "
1205                       "this station supports if no connection exists.\n");
1206         }
1207         if (z) {
1208                 IRDA_DEBUG(0, "Rejected control field control field contained an "
1209                       "invalid Nr count.\n");
1210         }
1211         irlap_do_event(self, RECV_FRMR_RSP, skb, info);
1212 }
1213
1214 /*
1215  * Function irlap_send_test_frame (self, daddr)
1216  *
1217  *    Send a test frame response
1218  *
1219  */
1220 void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr,
1221                            struct sk_buff *cmd)
1222 {
1223         struct sk_buff *tx_skb;
1224         struct test_frame *frame;
1225         __u8 *info;
1226
1227         tx_skb = alloc_skb(cmd->len + sizeof(struct test_frame), GFP_ATOMIC);
1228         if (!tx_skb)
1229                 return;
1230
1231         /* Broadcast frames must include saddr and daddr fields */
1232         if (caddr == CBROADCAST) {
1233                 frame = (struct test_frame *)
1234                         skb_put(tx_skb, sizeof(struct test_frame));
1235
1236                 /* Insert the swapped addresses */
1237                 frame->saddr = cpu_to_le32(self->saddr);
1238                 frame->daddr = cpu_to_le32(daddr);
1239         } else
1240                 frame = (struct test_frame *) skb_put(tx_skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);
1241
1242         frame->caddr = caddr;
1243         frame->control = TEST_RSP | PF_BIT;
1244
1245         /* Copy info */
1246         info = skb_put(tx_skb, cmd->len);
1247         memcpy(info, cmd->data, cmd->len);
1248
1249         /* Return to sender */
1250         irlap_wait_min_turn_around(self, &self->qos_tx);
1251         irlap_queue_xmit(self, tx_skb);
1252 }
1253
1254 /*
1255  * Function irlap_recv_test_frame (self, skb)
1256  *
1257  *    Receive a test frame
1258  *
1259  */
1260 static void irlap_recv_test_frame(struct irlap_cb *self, struct sk_buff *skb,
1261                                   struct irlap_info *info, int command)
1262 {
1263         struct test_frame *frame;
1264
1265         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
1266
1267         if (!pskb_may_pull(skb, sizeof(*frame))) {
1268                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
1269                 return;
1270         }
1271         frame = (struct test_frame *) skb->data;
1272
1273         /* Broadcast frames must carry saddr and daddr fields */
1274         if (info->caddr == CBROADCAST) {
1275                 if (skb->len < sizeof(struct test_frame)) {
1276                         IRDA_DEBUG(0, "%s() test frame too short!\n",
1277                                    __FUNCTION__);
1278                         return;
1279                 }
1280
1281                 /* Read and swap addresses */
1282                 info->daddr = le32_to_cpu(frame->saddr);
1283                 info->saddr = le32_to_cpu(frame->daddr);
1284
1285                 /* Make sure frame is addressed to us */
1286                 if ((info->saddr != self->saddr) &&
1287                     (info->saddr != BROADCAST)) {
1288                         return;
1289                 }
1290         }
1291
1292         if (command)
1293                 irlap_do_event(self, RECV_TEST_CMD, skb, info);
1294         else
1295                 irlap_do_event(self, RECV_TEST_RSP, skb, info);
1296 }
1297
1298 /*
1299  * Function irlap_driver_rcv (skb, netdev, ptype)
1300  *
1301  *    Called when a frame is received. Dispatches the right receive function
1302  *    for processing of the frame.
1303  *
1304  * Note on skb management :
1305  * After calling the higher layers of the IrDA stack, we always
1306  * kfree() the skb, which drop the reference count (and potentially
1307  * destroy it).
1308  * If a higher layer of the stack want to keep the skb around (to put
1309  * in a queue or pass it to the higher layer), it will need to use
1310  * skb_get() to keep a reference on it. This is usually done at the
1311  * LMP level in irlmp.c.
1312  * Jean II
1313  */
1314 int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,
1315                      struct packet_type *ptype, struct net_device *orig_dev)
1316 {
1317         struct irlap_info info;
1318         struct irlap_cb *self;
1319         int command;
1320         __u8 control;
1321
1322         /* FIXME: should we get our own field? */
1323         self = (struct irlap_cb *) dev->atalk_ptr;
1324
1325         /* If the net device is down, then IrLAP is gone! */
1326         if (!self || self->magic != LAP_MAGIC) {
1327                 dev_kfree_skb(skb);
1328                 return -1;
1329         }
1330
1331         /* We are no longer an "old" protocol, so we need to handle
1332          * share and non linear skbs. This should never happen, so
1333          * we don't need to be clever about it. Jean II */
1334         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
1335                 IRDA_ERROR("%s: can't clone shared skb!\n", __FUNCTION__);
1336                 dev_kfree_skb(skb);
1337                 return -1;
1338         }
1339
1340         /* Check if frame is large enough for parsing */
1341         if (!pskb_may_pull(skb, 2)) {
1342                 IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
1343                 dev_kfree_skb(skb);
1344                 return -1;
1345         }
1346
1347         command    = skb->data[0] & CMD_FRAME;
1348         info.caddr = skb->data[0] & CBROADCAST;
1349
1350         info.pf      = skb->data[1] &  PF_BIT;
1351         info.control = skb->data[1] & ~PF_BIT; /* Mask away poll/final bit */
1352
1353         control = info.control;
1354
1355         /*  First we check if this frame has a valid connection address */
1356         if ((info.caddr != self->caddr) && (info.caddr != CBROADCAST)) {
1357                 IRDA_DEBUG(0, "%s(), wrong connection address!\n",
1358                            __FUNCTION__);
1359                 goto out;
1360         }
1361         /*
1362          *  Optimize for the common case and check if the frame is an
1363          *  I(nformation) frame. Only I-frames have bit 0 set to 0
1364          */
1365         if (~control & 0x01) {
1366                 irlap_recv_i_frame(self, skb, &info, command);
1367                 goto out;
1368         }
1369         /*
1370          *  We now check is the frame is an S(upervisory) frame. Only
1371          *  S-frames have bit 0 set to 1 and bit 1 set to 0
1372          */
1373         if (~control & 0x02) {
1374                 /*
1375                  *  Received S(upervisory) frame, check which frame type it is
1376                  *  only the first nibble is of interest
1377                  */
1378                 switch (control & 0x0f) {
1379                 case RR:
1380                         irlap_recv_rr_frame(self, skb, &info, command);
1381                         break;
1382                 case RNR:
1383                         irlap_recv_rnr_frame(self, skb, &info, command);
1384                         break;
1385                 case REJ:
1386                         irlap_recv_rej_frame(self, skb, &info, command);
1387                         break;
1388                 case SREJ:
1389                         irlap_recv_srej_frame(self, skb, &info, command);
1390                         break;
1391                 default:
1392                         IRDA_WARNING("%s: Unknown S-frame %02x received!\n",
1393                                 __FUNCTION__, info.control);
1394                         break;
1395                 }
1396                 goto out;
1397         }
1398         /*
1399          *  This must be a C(ontrol) frame
1400          */
1401         switch (control) {
1402         case XID_RSP:
1403                 irlap_recv_discovery_xid_rsp(self, skb, &info);
1404                 break;
1405         case XID_CMD:
1406                 irlap_recv_discovery_xid_cmd(self, skb, &info);
1407                 break;
1408         case SNRM_CMD:
1409                 irlap_recv_snrm_cmd(self, skb, &info);
1410                 break;
1411         case DM_RSP:
1412                 irlap_do_event(self, RECV_DM_RSP, skb, &info);
1413                 break;
1414         case DISC_CMD: /* And RD_RSP since they have the same value */
1415                 irlap_recv_disc_frame(self, skb, &info, command);
1416                 break;
1417         case TEST_CMD:
1418                 irlap_recv_test_frame(self, skb, &info, command);
1419                 break;
1420         case UA_RSP:
1421                 irlap_recv_ua_frame(self, skb, &info);
1422                 break;
1423         case FRMR_RSP:
1424                 irlap_recv_frmr_frame(self, skb, &info);
1425                 break;
1426         case UI_FRAME:
1427                 irlap_recv_ui_frame(self, skb, &info);
1428                 break;
1429         default:
1430                 IRDA_WARNING("%s: Unknown frame %02x received!\n",
1431                                 __FUNCTION__, info.control);
1432                 break;
1433         }
1434 out:
1435         /* Always drop our reference on the skb */
1436         dev_kfree_skb(skb);
1437         return 0;
1438 }